1 //===--- SemaExpr.cpp - Semantic Analysis for Expressions -----------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //  This file implements semantic analysis for expressions.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Sema/SemaInternal.h"
15 #include "TreeTransform.h"
16 #include "clang/AST/ASTConsumer.h"
17 #include "clang/AST/ASTContext.h"
18 #include "clang/AST/ASTLambda.h"
19 #include "clang/AST/ASTMutationListener.h"
20 #include "clang/AST/CXXInheritance.h"
21 #include "clang/AST/DeclObjC.h"
22 #include "clang/AST/DeclTemplate.h"
23 #include "clang/AST/EvaluatedExprVisitor.h"
24 #include "clang/AST/Expr.h"
25 #include "clang/AST/ExprCXX.h"
26 #include "clang/AST/ExprObjC.h"
27 #include "clang/AST/RecursiveASTVisitor.h"
28 #include "clang/AST/TypeLoc.h"
29 #include "clang/Basic/PartialDiagnostic.h"
30 #include "clang/Basic/SourceManager.h"
31 #include "clang/Basic/TargetInfo.h"
32 #include "clang/Lex/LiteralSupport.h"
33 #include "clang/Lex/Preprocessor.h"
34 #include "clang/Sema/AnalysisBasedWarnings.h"
35 #include "clang/Sema/DeclSpec.h"
36 #include "clang/Sema/DelayedDiagnostic.h"
37 #include "clang/Sema/Designator.h"
38 #include "clang/Sema/Initialization.h"
39 #include "clang/Sema/Lookup.h"
40 #include "clang/Sema/ParsedTemplate.h"
41 #include "clang/Sema/Scope.h"
42 #include "clang/Sema/ScopeInfo.h"
43 #include "clang/Sema/SemaFixItUtils.h"
44 #include "clang/Sema/Template.h"
45 #include "llvm/Support/ConvertUTF.h"
46 using namespace clang;
47 using namespace sema;
48 
49 /// \brief Determine whether the use of this declaration is valid, without
50 /// emitting diagnostics.
CanUseDecl(NamedDecl * D)51 bool Sema::CanUseDecl(NamedDecl *D) {
52   // See if this is an auto-typed variable whose initializer we are parsing.
53   if (ParsingInitForAutoVars.count(D))
54     return false;
55 
56   // See if this is a deleted function.
57   if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
58     if (FD->isDeleted())
59       return false;
60 
61     // If the function has a deduced return type, and we can't deduce it,
62     // then we can't use it either.
63     if (getLangOpts().CPlusPlus14 && FD->getReturnType()->isUndeducedType() &&
64         DeduceReturnType(FD, SourceLocation(), /*Diagnose*/ false))
65       return false;
66   }
67 
68   // See if this function is unavailable.
69   if (D->getAvailability() == AR_Unavailable &&
70       cast<Decl>(CurContext)->getAvailability() != AR_Unavailable)
71     return false;
72 
73   return true;
74 }
75 
DiagnoseUnusedOfDecl(Sema & S,NamedDecl * D,SourceLocation Loc)76 static void DiagnoseUnusedOfDecl(Sema &S, NamedDecl *D, SourceLocation Loc) {
77   // Warn if this is used but marked unused.
78   if (D->hasAttr<UnusedAttr>()) {
79     const Decl *DC = cast<Decl>(S.getCurObjCLexicalContext());
80     if (!DC->hasAttr<UnusedAttr>())
81       S.Diag(Loc, diag::warn_used_but_marked_unused) << D->getDeclName();
82   }
83 }
84 
DiagnoseAvailabilityOfDecl(Sema & S,NamedDecl * D,SourceLocation Loc,const ObjCInterfaceDecl * UnknownObjCClass,bool ObjCPropertyAccess)85 static AvailabilityResult DiagnoseAvailabilityOfDecl(Sema &S,
86                               NamedDecl *D, SourceLocation Loc,
87                               const ObjCInterfaceDecl *UnknownObjCClass,
88                               bool ObjCPropertyAccess) {
89   // See if this declaration is unavailable or deprecated.
90   std::string Message;
91 
92   // Forward class declarations get their attributes from their definition.
93   if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(D)) {
94     if (IDecl->getDefinition())
95       D = IDecl->getDefinition();
96   }
97   AvailabilityResult Result = D->getAvailability(&Message);
98   if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D))
99     if (Result == AR_Available) {
100       const DeclContext *DC = ECD->getDeclContext();
101       if (const EnumDecl *TheEnumDecl = dyn_cast<EnumDecl>(DC))
102         Result = TheEnumDecl->getAvailability(&Message);
103     }
104 
105   const ObjCPropertyDecl *ObjCPDecl = nullptr;
106   if (Result == AR_Deprecated || Result == AR_Unavailable) {
107     if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
108       if (const ObjCPropertyDecl *PD = MD->findPropertyDecl()) {
109         AvailabilityResult PDeclResult = PD->getAvailability(nullptr);
110         if (PDeclResult == Result)
111           ObjCPDecl = PD;
112       }
113     }
114   }
115 
116   switch (Result) {
117     case AR_Available:
118     case AR_NotYetIntroduced:
119       break;
120 
121     case AR_Deprecated:
122       if (S.getCurContextAvailability() != AR_Deprecated)
123         S.EmitAvailabilityWarning(Sema::AD_Deprecation,
124                                   D, Message, Loc, UnknownObjCClass, ObjCPDecl,
125                                   ObjCPropertyAccess);
126       break;
127 
128     case AR_Unavailable:
129       if (S.getCurContextAvailability() != AR_Unavailable)
130         S.EmitAvailabilityWarning(Sema::AD_Unavailable,
131                                   D, Message, Loc, UnknownObjCClass, ObjCPDecl,
132                                   ObjCPropertyAccess);
133       break;
134 
135     }
136     return Result;
137 }
138 
139 /// \brief Emit a note explaining that this function is deleted.
NoteDeletedFunction(FunctionDecl * Decl)140 void Sema::NoteDeletedFunction(FunctionDecl *Decl) {
141   assert(Decl->isDeleted());
142 
143   CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Decl);
144 
145   if (Method && Method->isDeleted() && Method->isDefaulted()) {
146     // If the method was explicitly defaulted, point at that declaration.
147     if (!Method->isImplicit())
148       Diag(Decl->getLocation(), diag::note_implicitly_deleted);
149 
150     // Try to diagnose why this special member function was implicitly
151     // deleted. This might fail, if that reason no longer applies.
152     CXXSpecialMember CSM = getSpecialMember(Method);
153     if (CSM != CXXInvalid)
154       ShouldDeleteSpecialMember(Method, CSM, /*Diagnose=*/true);
155 
156     return;
157   }
158 
159   if (CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(Decl)) {
160     if (CXXConstructorDecl *BaseCD =
161             const_cast<CXXConstructorDecl*>(CD->getInheritedConstructor())) {
162       Diag(Decl->getLocation(), diag::note_inherited_deleted_here);
163       if (BaseCD->isDeleted()) {
164         NoteDeletedFunction(BaseCD);
165       } else {
166         // FIXME: An explanation of why exactly it can't be inherited
167         // would be nice.
168         Diag(BaseCD->getLocation(), diag::note_cannot_inherit);
169       }
170       return;
171     }
172   }
173 
174   Diag(Decl->getLocation(), diag::note_availability_specified_here)
175     << Decl << true;
176 }
177 
178 /// \brief Determine whether a FunctionDecl was ever declared with an
179 /// explicit storage class.
hasAnyExplicitStorageClass(const FunctionDecl * D)180 static bool hasAnyExplicitStorageClass(const FunctionDecl *D) {
181   for (auto I : D->redecls()) {
182     if (I->getStorageClass() != SC_None)
183       return true;
184   }
185   return false;
186 }
187 
188 /// \brief Check whether we're in an extern inline function and referring to a
189 /// variable or function with internal linkage (C11 6.7.4p3).
190 ///
191 /// This is only a warning because we used to silently accept this code, but
192 /// in many cases it will not behave correctly. This is not enabled in C++ mode
193 /// because the restriction language is a bit weaker (C++11 [basic.def.odr]p6)
194 /// and so while there may still be user mistakes, most of the time we can't
195 /// prove that there are errors.
diagnoseUseOfInternalDeclInInlineFunction(Sema & S,const NamedDecl * D,SourceLocation Loc)196 static void diagnoseUseOfInternalDeclInInlineFunction(Sema &S,
197                                                       const NamedDecl *D,
198                                                       SourceLocation Loc) {
199   // This is disabled under C++; there are too many ways for this to fire in
200   // contexts where the warning is a false positive, or where it is technically
201   // correct but benign.
202   if (S.getLangOpts().CPlusPlus)
203     return;
204 
205   // Check if this is an inlined function or method.
206   FunctionDecl *Current = S.getCurFunctionDecl();
207   if (!Current)
208     return;
209   if (!Current->isInlined())
210     return;
211   if (!Current->isExternallyVisible())
212     return;
213 
214   // Check if the decl has internal linkage.
215   if (D->getFormalLinkage() != InternalLinkage)
216     return;
217 
218   // Downgrade from ExtWarn to Extension if
219   //  (1) the supposedly external inline function is in the main file,
220   //      and probably won't be included anywhere else.
221   //  (2) the thing we're referencing is a pure function.
222   //  (3) the thing we're referencing is another inline function.
223   // This last can give us false negatives, but it's better than warning on
224   // wrappers for simple C library functions.
225   const FunctionDecl *UsedFn = dyn_cast<FunctionDecl>(D);
226   bool DowngradeWarning = S.getSourceManager().isInMainFile(Loc);
227   if (!DowngradeWarning && UsedFn)
228     DowngradeWarning = UsedFn->isInlined() || UsedFn->hasAttr<ConstAttr>();
229 
230   S.Diag(Loc, DowngradeWarning ? diag::ext_internal_in_extern_inline_quiet
231                                : diag::ext_internal_in_extern_inline)
232     << /*IsVar=*/!UsedFn << D;
233 
234   S.MaybeSuggestAddingStaticToDecl(Current);
235 
236   S.Diag(D->getCanonicalDecl()->getLocation(), diag::note_entity_declared_at)
237       << D;
238 }
239 
MaybeSuggestAddingStaticToDecl(const FunctionDecl * Cur)240 void Sema::MaybeSuggestAddingStaticToDecl(const FunctionDecl *Cur) {
241   const FunctionDecl *First = Cur->getFirstDecl();
242 
243   // Suggest "static" on the function, if possible.
244   if (!hasAnyExplicitStorageClass(First)) {
245     SourceLocation DeclBegin = First->getSourceRange().getBegin();
246     Diag(DeclBegin, diag::note_convert_inline_to_static)
247       << Cur << FixItHint::CreateInsertion(DeclBegin, "static ");
248   }
249 }
250 
251 /// \brief Determine whether the use of this declaration is valid, and
252 /// emit any corresponding diagnostics.
253 ///
254 /// This routine diagnoses various problems with referencing
255 /// declarations that can occur when using a declaration. For example,
256 /// it might warn if a deprecated or unavailable declaration is being
257 /// used, or produce an error (and return true) if a C++0x deleted
258 /// function is being used.
259 ///
260 /// \returns true if there was an error (this declaration cannot be
261 /// referenced), false otherwise.
262 ///
DiagnoseUseOfDecl(NamedDecl * D,SourceLocation Loc,const ObjCInterfaceDecl * UnknownObjCClass,bool ObjCPropertyAccess)263 bool Sema::DiagnoseUseOfDecl(NamedDecl *D, SourceLocation Loc,
264                              const ObjCInterfaceDecl *UnknownObjCClass,
265                              bool ObjCPropertyAccess) {
266   if (getLangOpts().CPlusPlus && isa<FunctionDecl>(D)) {
267     // If there were any diagnostics suppressed by template argument deduction,
268     // emit them now.
269     SuppressedDiagnosticsMap::iterator
270       Pos = SuppressedDiagnostics.find(D->getCanonicalDecl());
271     if (Pos != SuppressedDiagnostics.end()) {
272       SmallVectorImpl<PartialDiagnosticAt> &Suppressed = Pos->second;
273       for (unsigned I = 0, N = Suppressed.size(); I != N; ++I)
274         Diag(Suppressed[I].first, Suppressed[I].second);
275 
276       // Clear out the list of suppressed diagnostics, so that we don't emit
277       // them again for this specialization. However, we don't obsolete this
278       // entry from the table, because we want to avoid ever emitting these
279       // diagnostics again.
280       Suppressed.clear();
281     }
282 
283     // C++ [basic.start.main]p3:
284     //   The function 'main' shall not be used within a program.
285     if (cast<FunctionDecl>(D)->isMain())
286       Diag(Loc, diag::ext_main_used);
287   }
288 
289   // See if this is an auto-typed variable whose initializer we are parsing.
290   if (ParsingInitForAutoVars.count(D)) {
291     Diag(Loc, diag::err_auto_variable_cannot_appear_in_own_initializer)
292       << D->getDeclName();
293     return true;
294   }
295 
296   // See if this is a deleted function.
297   if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
298     if (FD->isDeleted()) {
299       Diag(Loc, diag::err_deleted_function_use);
300       NoteDeletedFunction(FD);
301       return true;
302     }
303 
304     // If the function has a deduced return type, and we can't deduce it,
305     // then we can't use it either.
306     if (getLangOpts().CPlusPlus14 && FD->getReturnType()->isUndeducedType() &&
307         DeduceReturnType(FD, Loc))
308       return true;
309   }
310   DiagnoseAvailabilityOfDecl(*this, D, Loc, UnknownObjCClass, ObjCPropertyAccess);
311 
312   DiagnoseUnusedOfDecl(*this, D, Loc);
313 
314   diagnoseUseOfInternalDeclInInlineFunction(*this, D, Loc);
315 
316   return false;
317 }
318 
319 /// \brief Retrieve the message suffix that should be added to a
320 /// diagnostic complaining about the given function being deleted or
321 /// unavailable.
getDeletedOrUnavailableSuffix(const FunctionDecl * FD)322 std::string Sema::getDeletedOrUnavailableSuffix(const FunctionDecl *FD) {
323   std::string Message;
324   if (FD->getAvailability(&Message))
325     return ": " + Message;
326 
327   return std::string();
328 }
329 
330 /// DiagnoseSentinelCalls - This routine checks whether a call or
331 /// message-send is to a declaration with the sentinel attribute, and
332 /// if so, it checks that the requirements of the sentinel are
333 /// satisfied.
DiagnoseSentinelCalls(NamedDecl * D,SourceLocation Loc,ArrayRef<Expr * > Args)334 void Sema::DiagnoseSentinelCalls(NamedDecl *D, SourceLocation Loc,
335                                  ArrayRef<Expr *> Args) {
336   const SentinelAttr *attr = D->getAttr<SentinelAttr>();
337   if (!attr)
338     return;
339 
340   // The number of formal parameters of the declaration.
341   unsigned numFormalParams;
342 
343   // The kind of declaration.  This is also an index into a %select in
344   // the diagnostic.
345   enum CalleeType { CT_Function, CT_Method, CT_Block } calleeType;
346 
347   if (ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
348     numFormalParams = MD->param_size();
349     calleeType = CT_Method;
350   } else if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
351     numFormalParams = FD->param_size();
352     calleeType = CT_Function;
353   } else if (isa<VarDecl>(D)) {
354     QualType type = cast<ValueDecl>(D)->getType();
355     const FunctionType *fn = nullptr;
356     if (const PointerType *ptr = type->getAs<PointerType>()) {
357       fn = ptr->getPointeeType()->getAs<FunctionType>();
358       if (!fn) return;
359       calleeType = CT_Function;
360     } else if (const BlockPointerType *ptr = type->getAs<BlockPointerType>()) {
361       fn = ptr->getPointeeType()->castAs<FunctionType>();
362       calleeType = CT_Block;
363     } else {
364       return;
365     }
366 
367     if (const FunctionProtoType *proto = dyn_cast<FunctionProtoType>(fn)) {
368       numFormalParams = proto->getNumParams();
369     } else {
370       numFormalParams = 0;
371     }
372   } else {
373     return;
374   }
375 
376   // "nullPos" is the number of formal parameters at the end which
377   // effectively count as part of the variadic arguments.  This is
378   // useful if you would prefer to not have *any* formal parameters,
379   // but the language forces you to have at least one.
380   unsigned nullPos = attr->getNullPos();
381   assert((nullPos == 0 || nullPos == 1) && "invalid null position on sentinel");
382   numFormalParams = (nullPos > numFormalParams ? 0 : numFormalParams - nullPos);
383 
384   // The number of arguments which should follow the sentinel.
385   unsigned numArgsAfterSentinel = attr->getSentinel();
386 
387   // If there aren't enough arguments for all the formal parameters,
388   // the sentinel, and the args after the sentinel, complain.
389   if (Args.size() < numFormalParams + numArgsAfterSentinel + 1) {
390     Diag(Loc, diag::warn_not_enough_argument) << D->getDeclName();
391     Diag(D->getLocation(), diag::note_sentinel_here) << int(calleeType);
392     return;
393   }
394 
395   // Otherwise, find the sentinel expression.
396   Expr *sentinelExpr = Args[Args.size() - numArgsAfterSentinel - 1];
397   if (!sentinelExpr) return;
398   if (sentinelExpr->isValueDependent()) return;
399   if (Context.isSentinelNullExpr(sentinelExpr)) return;
400 
401   // Pick a reasonable string to insert.  Optimistically use 'nil', 'nullptr',
402   // or 'NULL' if those are actually defined in the context.  Only use
403   // 'nil' for ObjC methods, where it's much more likely that the
404   // variadic arguments form a list of object pointers.
405   SourceLocation MissingNilLoc
406     = PP.getLocForEndOfToken(sentinelExpr->getLocEnd());
407   std::string NullValue;
408   if (calleeType == CT_Method &&
409       PP.getIdentifierInfo("nil")->hasMacroDefinition())
410     NullValue = "nil";
411   else if (getLangOpts().CPlusPlus11)
412     NullValue = "nullptr";
413   else if (PP.getIdentifierInfo("NULL")->hasMacroDefinition())
414     NullValue = "NULL";
415   else
416     NullValue = "(void*) 0";
417 
418   if (MissingNilLoc.isInvalid())
419     Diag(Loc, diag::warn_missing_sentinel) << int(calleeType);
420   else
421     Diag(MissingNilLoc, diag::warn_missing_sentinel)
422       << int(calleeType)
423       << FixItHint::CreateInsertion(MissingNilLoc, ", " + NullValue);
424   Diag(D->getLocation(), diag::note_sentinel_here) << int(calleeType);
425 }
426 
getExprRange(Expr * E) const427 SourceRange Sema::getExprRange(Expr *E) const {
428   return E ? E->getSourceRange() : SourceRange();
429 }
430 
431 //===----------------------------------------------------------------------===//
432 //  Standard Promotions and Conversions
433 //===----------------------------------------------------------------------===//
434 
435 /// DefaultFunctionArrayConversion (C99 6.3.2.1p3, C99 6.3.2.1p4).
DefaultFunctionArrayConversion(Expr * E)436 ExprResult Sema::DefaultFunctionArrayConversion(Expr *E) {
437   // Handle any placeholder expressions which made it here.
438   if (E->getType()->isPlaceholderType()) {
439     ExprResult result = CheckPlaceholderExpr(E);
440     if (result.isInvalid()) return ExprError();
441     E = result.get();
442   }
443 
444   QualType Ty = E->getType();
445   assert(!Ty.isNull() && "DefaultFunctionArrayConversion - missing type");
446 
447   if (Ty->isFunctionType()) {
448     // If we are here, we are not calling a function but taking
449     // its address (which is not allowed in OpenCL v1.0 s6.8.a.3).
450     if (getLangOpts().OpenCL) {
451       Diag(E->getExprLoc(), diag::err_opencl_taking_function_address);
452       return ExprError();
453     }
454     E = ImpCastExprToType(E, Context.getPointerType(Ty),
455                           CK_FunctionToPointerDecay).get();
456   } else if (Ty->isArrayType()) {
457     // In C90 mode, arrays only promote to pointers if the array expression is
458     // an lvalue.  The relevant legalese is C90 6.2.2.1p3: "an lvalue that has
459     // type 'array of type' is converted to an expression that has type 'pointer
460     // to type'...".  In C99 this was changed to: C99 6.3.2.1p3: "an expression
461     // that has type 'array of type' ...".  The relevant change is "an lvalue"
462     // (C90) to "an expression" (C99).
463     //
464     // C++ 4.2p1:
465     // An lvalue or rvalue of type "array of N T" or "array of unknown bound of
466     // T" can be converted to an rvalue of type "pointer to T".
467     //
468     if (getLangOpts().C99 || getLangOpts().CPlusPlus || E->isLValue())
469       E = ImpCastExprToType(E, Context.getArrayDecayedType(Ty),
470                             CK_ArrayToPointerDecay).get();
471   }
472   return E;
473 }
474 
CheckForNullPointerDereference(Sema & S,Expr * E)475 static void CheckForNullPointerDereference(Sema &S, Expr *E) {
476   // Check to see if we are dereferencing a null pointer.  If so,
477   // and if not volatile-qualified, this is undefined behavior that the
478   // optimizer will delete, so warn about it.  People sometimes try to use this
479   // to get a deterministic trap and are surprised by clang's behavior.  This
480   // only handles the pattern "*null", which is a very syntactic check.
481   if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E->IgnoreParenCasts()))
482     if (UO->getOpcode() == UO_Deref &&
483         UO->getSubExpr()->IgnoreParenCasts()->
484           isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull) &&
485         !UO->getType().isVolatileQualified()) {
486     S.DiagRuntimeBehavior(UO->getOperatorLoc(), UO,
487                           S.PDiag(diag::warn_indirection_through_null)
488                             << UO->getSubExpr()->getSourceRange());
489     S.DiagRuntimeBehavior(UO->getOperatorLoc(), UO,
490                         S.PDiag(diag::note_indirection_through_null));
491   }
492 }
493 
DiagnoseDirectIsaAccess(Sema & S,const ObjCIvarRefExpr * OIRE,SourceLocation AssignLoc,const Expr * RHS)494 static void DiagnoseDirectIsaAccess(Sema &S, const ObjCIvarRefExpr *OIRE,
495                                     SourceLocation AssignLoc,
496                                     const Expr* RHS) {
497   const ObjCIvarDecl *IV = OIRE->getDecl();
498   if (!IV)
499     return;
500 
501   DeclarationName MemberName = IV->getDeclName();
502   IdentifierInfo *Member = MemberName.getAsIdentifierInfo();
503   if (!Member || !Member->isStr("isa"))
504     return;
505 
506   const Expr *Base = OIRE->getBase();
507   QualType BaseType = Base->getType();
508   if (OIRE->isArrow())
509     BaseType = BaseType->getPointeeType();
510   if (const ObjCObjectType *OTy = BaseType->getAs<ObjCObjectType>())
511     if (ObjCInterfaceDecl *IDecl = OTy->getInterface()) {
512       ObjCInterfaceDecl *ClassDeclared = nullptr;
513       ObjCIvarDecl *IV = IDecl->lookupInstanceVariable(Member, ClassDeclared);
514       if (!ClassDeclared->getSuperClass()
515           && (*ClassDeclared->ivar_begin()) == IV) {
516         if (RHS) {
517           NamedDecl *ObjectSetClass =
518             S.LookupSingleName(S.TUScope,
519                                &S.Context.Idents.get("object_setClass"),
520                                SourceLocation(), S.LookupOrdinaryName);
521           if (ObjectSetClass) {
522             SourceLocation RHSLocEnd = S.PP.getLocForEndOfToken(RHS->getLocEnd());
523             S.Diag(OIRE->getExprLoc(), diag::warn_objc_isa_assign) <<
524             FixItHint::CreateInsertion(OIRE->getLocStart(), "object_setClass(") <<
525             FixItHint::CreateReplacement(SourceRange(OIRE->getOpLoc(),
526                                                      AssignLoc), ",") <<
527             FixItHint::CreateInsertion(RHSLocEnd, ")");
528           }
529           else
530             S.Diag(OIRE->getLocation(), diag::warn_objc_isa_assign);
531         } else {
532           NamedDecl *ObjectGetClass =
533             S.LookupSingleName(S.TUScope,
534                                &S.Context.Idents.get("object_getClass"),
535                                SourceLocation(), S.LookupOrdinaryName);
536           if (ObjectGetClass)
537             S.Diag(OIRE->getExprLoc(), diag::warn_objc_isa_use) <<
538             FixItHint::CreateInsertion(OIRE->getLocStart(), "object_getClass(") <<
539             FixItHint::CreateReplacement(
540                                          SourceRange(OIRE->getOpLoc(),
541                                                      OIRE->getLocEnd()), ")");
542           else
543             S.Diag(OIRE->getLocation(), diag::warn_objc_isa_use);
544         }
545         S.Diag(IV->getLocation(), diag::note_ivar_decl);
546       }
547     }
548 }
549 
DefaultLvalueConversion(Expr * E)550 ExprResult Sema::DefaultLvalueConversion(Expr *E) {
551   // Handle any placeholder expressions which made it here.
552   if (E->getType()->isPlaceholderType()) {
553     ExprResult result = CheckPlaceholderExpr(E);
554     if (result.isInvalid()) return ExprError();
555     E = result.get();
556   }
557 
558   // C++ [conv.lval]p1:
559   //   A glvalue of a non-function, non-array type T can be
560   //   converted to a prvalue.
561   if (!E->isGLValue()) return E;
562 
563   QualType T = E->getType();
564   assert(!T.isNull() && "r-value conversion on typeless expression?");
565 
566   // We don't want to throw lvalue-to-rvalue casts on top of
567   // expressions of certain types in C++.
568   if (getLangOpts().CPlusPlus &&
569       (E->getType() == Context.OverloadTy ||
570        T->isDependentType() ||
571        T->isRecordType()))
572     return E;
573 
574   // The C standard is actually really unclear on this point, and
575   // DR106 tells us what the result should be but not why.  It's
576   // generally best to say that void types just doesn't undergo
577   // lvalue-to-rvalue at all.  Note that expressions of unqualified
578   // 'void' type are never l-values, but qualified void can be.
579   if (T->isVoidType())
580     return E;
581 
582   // OpenCL usually rejects direct accesses to values of 'half' type.
583   if (getLangOpts().OpenCL && !getOpenCLOptions().cl_khr_fp16 &&
584       T->isHalfType()) {
585     Diag(E->getExprLoc(), diag::err_opencl_half_load_store)
586       << 0 << T;
587     return ExprError();
588   }
589 
590   CheckForNullPointerDereference(*this, E);
591   if (const ObjCIsaExpr *OISA = dyn_cast<ObjCIsaExpr>(E->IgnoreParenCasts())) {
592     NamedDecl *ObjectGetClass = LookupSingleName(TUScope,
593                                      &Context.Idents.get("object_getClass"),
594                                      SourceLocation(), LookupOrdinaryName);
595     if (ObjectGetClass)
596       Diag(E->getExprLoc(), diag::warn_objc_isa_use) <<
597         FixItHint::CreateInsertion(OISA->getLocStart(), "object_getClass(") <<
598         FixItHint::CreateReplacement(
599                     SourceRange(OISA->getOpLoc(), OISA->getIsaMemberLoc()), ")");
600     else
601       Diag(E->getExprLoc(), diag::warn_objc_isa_use);
602   }
603   else if (const ObjCIvarRefExpr *OIRE =
604             dyn_cast<ObjCIvarRefExpr>(E->IgnoreParenCasts()))
605     DiagnoseDirectIsaAccess(*this, OIRE, SourceLocation(), /* Expr*/nullptr);
606 
607   // C++ [conv.lval]p1:
608   //   [...] If T is a non-class type, the type of the prvalue is the
609   //   cv-unqualified version of T. Otherwise, the type of the
610   //   rvalue is T.
611   //
612   // C99 6.3.2.1p2:
613   //   If the lvalue has qualified type, the value has the unqualified
614   //   version of the type of the lvalue; otherwise, the value has the
615   //   type of the lvalue.
616   if (T.hasQualifiers())
617     T = T.getUnqualifiedType();
618 
619   UpdateMarkingForLValueToRValue(E);
620 
621   // Loading a __weak object implicitly retains the value, so we need a cleanup to
622   // balance that.
623   if (getLangOpts().ObjCAutoRefCount &&
624       E->getType().getObjCLifetime() == Qualifiers::OCL_Weak)
625     ExprNeedsCleanups = true;
626 
627   ExprResult Res = ImplicitCastExpr::Create(Context, T, CK_LValueToRValue, E,
628                                             nullptr, VK_RValue);
629 
630   // C11 6.3.2.1p2:
631   //   ... if the lvalue has atomic type, the value has the non-atomic version
632   //   of the type of the lvalue ...
633   if (const AtomicType *Atomic = T->getAs<AtomicType>()) {
634     T = Atomic->getValueType().getUnqualifiedType();
635     Res = ImplicitCastExpr::Create(Context, T, CK_AtomicToNonAtomic, Res.get(),
636                                    nullptr, VK_RValue);
637   }
638 
639   return Res;
640 }
641 
DefaultFunctionArrayLvalueConversion(Expr * E)642 ExprResult Sema::DefaultFunctionArrayLvalueConversion(Expr *E) {
643   ExprResult Res = DefaultFunctionArrayConversion(E);
644   if (Res.isInvalid())
645     return ExprError();
646   Res = DefaultLvalueConversion(Res.get());
647   if (Res.isInvalid())
648     return ExprError();
649   return Res;
650 }
651 
652 /// CallExprUnaryConversions - a special case of an unary conversion
653 /// performed on a function designator of a call expression.
CallExprUnaryConversions(Expr * E)654 ExprResult Sema::CallExprUnaryConversions(Expr *E) {
655   QualType Ty = E->getType();
656   ExprResult Res = E;
657   // Only do implicit cast for a function type, but not for a pointer
658   // to function type.
659   if (Ty->isFunctionType()) {
660     Res = ImpCastExprToType(E, Context.getPointerType(Ty),
661                             CK_FunctionToPointerDecay).get();
662     if (Res.isInvalid())
663       return ExprError();
664   }
665   Res = DefaultLvalueConversion(Res.get());
666   if (Res.isInvalid())
667     return ExprError();
668   return Res.get();
669 }
670 
671 /// UsualUnaryConversions - Performs various conversions that are common to most
672 /// operators (C99 6.3). The conversions of array and function types are
673 /// sometimes suppressed. For example, the array->pointer conversion doesn't
674 /// apply if the array is an argument to the sizeof or address (&) operators.
675 /// In these instances, this routine should *not* be called.
UsualUnaryConversions(Expr * E)676 ExprResult Sema::UsualUnaryConversions(Expr *E) {
677   // First, convert to an r-value.
678   ExprResult Res = DefaultFunctionArrayLvalueConversion(E);
679   if (Res.isInvalid())
680     return ExprError();
681   E = Res.get();
682 
683   QualType Ty = E->getType();
684   assert(!Ty.isNull() && "UsualUnaryConversions - missing type");
685 
686   // Half FP have to be promoted to float unless it is natively supported
687   if (Ty->isHalfType() && !getLangOpts().NativeHalfType)
688     return ImpCastExprToType(Res.get(), Context.FloatTy, CK_FloatingCast);
689 
690   // Try to perform integral promotions if the object has a theoretically
691   // promotable type.
692   if (Ty->isIntegralOrUnscopedEnumerationType()) {
693     // C99 6.3.1.1p2:
694     //
695     //   The following may be used in an expression wherever an int or
696     //   unsigned int may be used:
697     //     - an object or expression with an integer type whose integer
698     //       conversion rank is less than or equal to the rank of int
699     //       and unsigned int.
700     //     - A bit-field of type _Bool, int, signed int, or unsigned int.
701     //
702     //   If an int can represent all values of the original type, the
703     //   value is converted to an int; otherwise, it is converted to an
704     //   unsigned int. These are called the integer promotions. All
705     //   other types are unchanged by the integer promotions.
706 
707     QualType PTy = Context.isPromotableBitField(E);
708     if (!PTy.isNull()) {
709       E = ImpCastExprToType(E, PTy, CK_IntegralCast).get();
710       return E;
711     }
712     if (Ty->isPromotableIntegerType()) {
713       QualType PT = Context.getPromotedIntegerType(Ty);
714       E = ImpCastExprToType(E, PT, CK_IntegralCast).get();
715       return E;
716     }
717   }
718   return E;
719 }
720 
721 /// DefaultArgumentPromotion (C99 6.5.2.2p6). Used for function calls that
722 /// do not have a prototype. Arguments that have type float or __fp16
723 /// are promoted to double. All other argument types are converted by
724 /// UsualUnaryConversions().
DefaultArgumentPromotion(Expr * E)725 ExprResult Sema::DefaultArgumentPromotion(Expr *E) {
726   QualType Ty = E->getType();
727   assert(!Ty.isNull() && "DefaultArgumentPromotion - missing type");
728 
729   ExprResult Res = UsualUnaryConversions(E);
730   if (Res.isInvalid())
731     return ExprError();
732   E = Res.get();
733 
734   // If this is a 'float' or '__fp16' (CVR qualified or typedef) promote to
735   // double.
736   const BuiltinType *BTy = Ty->getAs<BuiltinType>();
737   if (BTy && (BTy->getKind() == BuiltinType::Half ||
738               BTy->getKind() == BuiltinType::Float))
739     E = ImpCastExprToType(E, Context.DoubleTy, CK_FloatingCast).get();
740 
741   // C++ performs lvalue-to-rvalue conversion as a default argument
742   // promotion, even on class types, but note:
743   //   C++11 [conv.lval]p2:
744   //     When an lvalue-to-rvalue conversion occurs in an unevaluated
745   //     operand or a subexpression thereof the value contained in the
746   //     referenced object is not accessed. Otherwise, if the glvalue
747   //     has a class type, the conversion copy-initializes a temporary
748   //     of type T from the glvalue and the result of the conversion
749   //     is a prvalue for the temporary.
750   // FIXME: add some way to gate this entire thing for correctness in
751   // potentially potentially evaluated contexts.
752   if (getLangOpts().CPlusPlus && E->isGLValue() && !isUnevaluatedContext()) {
753     ExprResult Temp = PerformCopyInitialization(
754                        InitializedEntity::InitializeTemporary(E->getType()),
755                                                 E->getExprLoc(), E);
756     if (Temp.isInvalid())
757       return ExprError();
758     E = Temp.get();
759   }
760 
761   return E;
762 }
763 
764 /// Determine the degree of POD-ness for an expression.
765 /// Incomplete types are considered POD, since this check can be performed
766 /// when we're in an unevaluated context.
isValidVarArgType(const QualType & Ty)767 Sema::VarArgKind Sema::isValidVarArgType(const QualType &Ty) {
768   if (Ty->isIncompleteType()) {
769     // C++11 [expr.call]p7:
770     //   After these conversions, if the argument does not have arithmetic,
771     //   enumeration, pointer, pointer to member, or class type, the program
772     //   is ill-formed.
773     //
774     // Since we've already performed array-to-pointer and function-to-pointer
775     // decay, the only such type in C++ is cv void. This also handles
776     // initializer lists as variadic arguments.
777     if (Ty->isVoidType())
778       return VAK_Invalid;
779 
780     if (Ty->isObjCObjectType())
781       return VAK_Invalid;
782     return VAK_Valid;
783   }
784 
785   if (Ty.isCXX98PODType(Context))
786     return VAK_Valid;
787 
788   // C++11 [expr.call]p7:
789   //   Passing a potentially-evaluated argument of class type (Clause 9)
790   //   having a non-trivial copy constructor, a non-trivial move constructor,
791   //   or a non-trivial destructor, with no corresponding parameter,
792   //   is conditionally-supported with implementation-defined semantics.
793   if (getLangOpts().CPlusPlus11 && !Ty->isDependentType())
794     if (CXXRecordDecl *Record = Ty->getAsCXXRecordDecl())
795       if (!Record->hasNonTrivialCopyConstructor() &&
796           !Record->hasNonTrivialMoveConstructor() &&
797           !Record->hasNonTrivialDestructor())
798         return VAK_ValidInCXX11;
799 
800   if (getLangOpts().ObjCAutoRefCount && Ty->isObjCLifetimeType())
801     return VAK_Valid;
802 
803   if (Ty->isObjCObjectType())
804     return VAK_Invalid;
805 
806   if (getLangOpts().MSVCCompat)
807     return VAK_MSVCUndefined;
808 
809   // FIXME: In C++11, these cases are conditionally-supported, meaning we're
810   // permitted to reject them. We should consider doing so.
811   return VAK_Undefined;
812 }
813 
checkVariadicArgument(const Expr * E,VariadicCallType CT)814 void Sema::checkVariadicArgument(const Expr *E, VariadicCallType CT) {
815   // Don't allow one to pass an Objective-C interface to a vararg.
816   const QualType &Ty = E->getType();
817   VarArgKind VAK = isValidVarArgType(Ty);
818 
819   // Complain about passing non-POD types through varargs.
820   switch (VAK) {
821   case VAK_ValidInCXX11:
822     DiagRuntimeBehavior(
823         E->getLocStart(), nullptr,
824         PDiag(diag::warn_cxx98_compat_pass_non_pod_arg_to_vararg)
825           << Ty << CT);
826     // Fall through.
827   case VAK_Valid:
828     if (Ty->isRecordType()) {
829       // This is unlikely to be what the user intended. If the class has a
830       // 'c_str' member function, the user probably meant to call that.
831       DiagRuntimeBehavior(E->getLocStart(), nullptr,
832                           PDiag(diag::warn_pass_class_arg_to_vararg)
833                             << Ty << CT << hasCStrMethod(E) << ".c_str()");
834     }
835     break;
836 
837   case VAK_Undefined:
838   case VAK_MSVCUndefined:
839     DiagRuntimeBehavior(
840         E->getLocStart(), nullptr,
841         PDiag(diag::warn_cannot_pass_non_pod_arg_to_vararg)
842           << getLangOpts().CPlusPlus11 << Ty << CT);
843     break;
844 
845   case VAK_Invalid:
846     if (Ty->isObjCObjectType())
847       DiagRuntimeBehavior(
848           E->getLocStart(), nullptr,
849           PDiag(diag::err_cannot_pass_objc_interface_to_vararg)
850             << Ty << CT);
851     else
852       Diag(E->getLocStart(), diag::err_cannot_pass_to_vararg)
853         << isa<InitListExpr>(E) << Ty << CT;
854     break;
855   }
856 }
857 
858 /// DefaultVariadicArgumentPromotion - Like DefaultArgumentPromotion, but
859 /// will create a trap if the resulting type is not a POD type.
DefaultVariadicArgumentPromotion(Expr * E,VariadicCallType CT,FunctionDecl * FDecl)860 ExprResult Sema::DefaultVariadicArgumentPromotion(Expr *E, VariadicCallType CT,
861                                                   FunctionDecl *FDecl) {
862   if (const BuiltinType *PlaceholderTy = E->getType()->getAsPlaceholderType()) {
863     // Strip the unbridged-cast placeholder expression off, if applicable.
864     if (PlaceholderTy->getKind() == BuiltinType::ARCUnbridgedCast &&
865         (CT == VariadicMethod ||
866          (FDecl && FDecl->hasAttr<CFAuditedTransferAttr>()))) {
867       E = stripARCUnbridgedCast(E);
868 
869     // Otherwise, do normal placeholder checking.
870     } else {
871       ExprResult ExprRes = CheckPlaceholderExpr(E);
872       if (ExprRes.isInvalid())
873         return ExprError();
874       E = ExprRes.get();
875     }
876   }
877 
878   ExprResult ExprRes = DefaultArgumentPromotion(E);
879   if (ExprRes.isInvalid())
880     return ExprError();
881   E = ExprRes.get();
882 
883   // Diagnostics regarding non-POD argument types are
884   // emitted along with format string checking in Sema::CheckFunctionCall().
885   if (isValidVarArgType(E->getType()) == VAK_Undefined) {
886     // Turn this into a trap.
887     CXXScopeSpec SS;
888     SourceLocation TemplateKWLoc;
889     UnqualifiedId Name;
890     Name.setIdentifier(PP.getIdentifierInfo("__builtin_trap"),
891                        E->getLocStart());
892     ExprResult TrapFn = ActOnIdExpression(TUScope, SS, TemplateKWLoc,
893                                           Name, true, false);
894     if (TrapFn.isInvalid())
895       return ExprError();
896 
897     ExprResult Call = ActOnCallExpr(TUScope, TrapFn.get(),
898                                     E->getLocStart(), None,
899                                     E->getLocEnd());
900     if (Call.isInvalid())
901       return ExprError();
902 
903     ExprResult Comma = ActOnBinOp(TUScope, E->getLocStart(), tok::comma,
904                                   Call.get(), E);
905     if (Comma.isInvalid())
906       return ExprError();
907     return Comma.get();
908   }
909 
910   if (!getLangOpts().CPlusPlus &&
911       RequireCompleteType(E->getExprLoc(), E->getType(),
912                           diag::err_call_incomplete_argument))
913     return ExprError();
914 
915   return E;
916 }
917 
918 /// \brief Converts an integer to complex float type.  Helper function of
919 /// UsualArithmeticConversions()
920 ///
921 /// \return false if the integer expression is an integer type and is
922 /// successfully converted to the complex type.
handleIntegerToComplexFloatConversion(Sema & S,ExprResult & IntExpr,ExprResult & ComplexExpr,QualType IntTy,QualType ComplexTy,bool SkipCast)923 static bool handleIntegerToComplexFloatConversion(Sema &S, ExprResult &IntExpr,
924                                                   ExprResult &ComplexExpr,
925                                                   QualType IntTy,
926                                                   QualType ComplexTy,
927                                                   bool SkipCast) {
928   if (IntTy->isComplexType() || IntTy->isRealFloatingType()) return true;
929   if (SkipCast) return false;
930   if (IntTy->isIntegerType()) {
931     QualType fpTy = cast<ComplexType>(ComplexTy)->getElementType();
932     IntExpr = S.ImpCastExprToType(IntExpr.get(), fpTy, CK_IntegralToFloating);
933     IntExpr = S.ImpCastExprToType(IntExpr.get(), ComplexTy,
934                                   CK_FloatingRealToComplex);
935   } else {
936     assert(IntTy->isComplexIntegerType());
937     IntExpr = S.ImpCastExprToType(IntExpr.get(), ComplexTy,
938                                   CK_IntegralComplexToFloatingComplex);
939   }
940   return false;
941 }
942 
943 /// \brief Handle arithmetic conversion with complex types.  Helper function of
944 /// UsualArithmeticConversions()
handleComplexFloatConversion(Sema & S,ExprResult & LHS,ExprResult & RHS,QualType LHSType,QualType RHSType,bool IsCompAssign)945 static QualType handleComplexFloatConversion(Sema &S, ExprResult &LHS,
946                                              ExprResult &RHS, QualType LHSType,
947                                              QualType RHSType,
948                                              bool IsCompAssign) {
949   // if we have an integer operand, the result is the complex type.
950   if (!handleIntegerToComplexFloatConversion(S, RHS, LHS, RHSType, LHSType,
951                                              /*skipCast*/false))
952     return LHSType;
953   if (!handleIntegerToComplexFloatConversion(S, LHS, RHS, LHSType, RHSType,
954                                              /*skipCast*/IsCompAssign))
955     return RHSType;
956 
957   // This handles complex/complex, complex/float, or float/complex.
958   // When both operands are complex, the shorter operand is converted to the
959   // type of the longer, and that is the type of the result. This corresponds
960   // to what is done when combining two real floating-point operands.
961   // The fun begins when size promotion occur across type domains.
962   // From H&S 6.3.4: When one operand is complex and the other is a real
963   // floating-point type, the less precise type is converted, within it's
964   // real or complex domain, to the precision of the other type. For example,
965   // when combining a "long double" with a "double _Complex", the
966   // "double _Complex" is promoted to "long double _Complex".
967 
968   // Compute the rank of the two types, regardless of whether they are complex.
969   int Order = S.Context.getFloatingTypeOrder(LHSType, RHSType);
970 
971   auto *LHSComplexType = dyn_cast<ComplexType>(LHSType);
972   auto *RHSComplexType = dyn_cast<ComplexType>(RHSType);
973   QualType LHSElementType =
974       LHSComplexType ? LHSComplexType->getElementType() : LHSType;
975   QualType RHSElementType =
976       RHSComplexType ? RHSComplexType->getElementType() : RHSType;
977 
978   QualType ResultType = S.Context.getComplexType(LHSElementType);
979   if (Order < 0) {
980     // Promote the precision of the LHS if not an assignment.
981     ResultType = S.Context.getComplexType(RHSElementType);
982     if (!IsCompAssign) {
983       if (LHSComplexType)
984         LHS =
985             S.ImpCastExprToType(LHS.get(), ResultType, CK_FloatingComplexCast);
986       else
987         LHS = S.ImpCastExprToType(LHS.get(), RHSElementType, CK_FloatingCast);
988     }
989   } else if (Order > 0) {
990     // Promote the precision of the RHS.
991     if (RHSComplexType)
992       RHS = S.ImpCastExprToType(RHS.get(), ResultType, CK_FloatingComplexCast);
993     else
994       RHS = S.ImpCastExprToType(RHS.get(), LHSElementType, CK_FloatingCast);
995   }
996   return ResultType;
997 }
998 
999 /// \brief Hande arithmetic conversion from integer to float.  Helper function
1000 /// of UsualArithmeticConversions()
handleIntToFloatConversion(Sema & S,ExprResult & FloatExpr,ExprResult & IntExpr,QualType FloatTy,QualType IntTy,bool ConvertFloat,bool ConvertInt)1001 static QualType handleIntToFloatConversion(Sema &S, ExprResult &FloatExpr,
1002                                            ExprResult &IntExpr,
1003                                            QualType FloatTy, QualType IntTy,
1004                                            bool ConvertFloat, bool ConvertInt) {
1005   if (IntTy->isIntegerType()) {
1006     if (ConvertInt)
1007       // Convert intExpr to the lhs floating point type.
1008       IntExpr = S.ImpCastExprToType(IntExpr.get(), FloatTy,
1009                                     CK_IntegralToFloating);
1010     return FloatTy;
1011   }
1012 
1013   // Convert both sides to the appropriate complex float.
1014   assert(IntTy->isComplexIntegerType());
1015   QualType result = S.Context.getComplexType(FloatTy);
1016 
1017   // _Complex int -> _Complex float
1018   if (ConvertInt)
1019     IntExpr = S.ImpCastExprToType(IntExpr.get(), result,
1020                                   CK_IntegralComplexToFloatingComplex);
1021 
1022   // float -> _Complex float
1023   if (ConvertFloat)
1024     FloatExpr = S.ImpCastExprToType(FloatExpr.get(), result,
1025                                     CK_FloatingRealToComplex);
1026 
1027   return result;
1028 }
1029 
1030 /// \brief Handle arithmethic conversion with floating point types.  Helper
1031 /// function of UsualArithmeticConversions()
handleFloatConversion(Sema & S,ExprResult & LHS,ExprResult & RHS,QualType LHSType,QualType RHSType,bool IsCompAssign)1032 static QualType handleFloatConversion(Sema &S, ExprResult &LHS,
1033                                       ExprResult &RHS, QualType LHSType,
1034                                       QualType RHSType, bool IsCompAssign) {
1035   bool LHSFloat = LHSType->isRealFloatingType();
1036   bool RHSFloat = RHSType->isRealFloatingType();
1037 
1038   // If we have two real floating types, convert the smaller operand
1039   // to the bigger result.
1040   if (LHSFloat && RHSFloat) {
1041     int order = S.Context.getFloatingTypeOrder(LHSType, RHSType);
1042     if (order > 0) {
1043       RHS = S.ImpCastExprToType(RHS.get(), LHSType, CK_FloatingCast);
1044       return LHSType;
1045     }
1046 
1047     assert(order < 0 && "illegal float comparison");
1048     if (!IsCompAssign)
1049       LHS = S.ImpCastExprToType(LHS.get(), RHSType, CK_FloatingCast);
1050     return RHSType;
1051   }
1052 
1053   if (LHSFloat)
1054     return handleIntToFloatConversion(S, LHS, RHS, LHSType, RHSType,
1055                                       /*convertFloat=*/!IsCompAssign,
1056                                       /*convertInt=*/ true);
1057   assert(RHSFloat);
1058   return handleIntToFloatConversion(S, RHS, LHS, RHSType, LHSType,
1059                                     /*convertInt=*/ true,
1060                                     /*convertFloat=*/!IsCompAssign);
1061 }
1062 
1063 typedef ExprResult PerformCastFn(Sema &S, Expr *operand, QualType toType);
1064 
1065 namespace {
1066 /// These helper callbacks are placed in an anonymous namespace to
1067 /// permit their use as function template parameters.
doIntegralCast(Sema & S,Expr * op,QualType toType)1068 ExprResult doIntegralCast(Sema &S, Expr *op, QualType toType) {
1069   return S.ImpCastExprToType(op, toType, CK_IntegralCast);
1070 }
1071 
doComplexIntegralCast(Sema & S,Expr * op,QualType toType)1072 ExprResult doComplexIntegralCast(Sema &S, Expr *op, QualType toType) {
1073   return S.ImpCastExprToType(op, S.Context.getComplexType(toType),
1074                              CK_IntegralComplexCast);
1075 }
1076 }
1077 
1078 /// \brief Handle integer arithmetic conversions.  Helper function of
1079 /// UsualArithmeticConversions()
1080 template <PerformCastFn doLHSCast, PerformCastFn doRHSCast>
handleIntegerConversion(Sema & S,ExprResult & LHS,ExprResult & RHS,QualType LHSType,QualType RHSType,bool IsCompAssign)1081 static QualType handleIntegerConversion(Sema &S, ExprResult &LHS,
1082                                         ExprResult &RHS, QualType LHSType,
1083                                         QualType RHSType, bool IsCompAssign) {
1084   // The rules for this case are in C99 6.3.1.8
1085   int order = S.Context.getIntegerTypeOrder(LHSType, RHSType);
1086   bool LHSSigned = LHSType->hasSignedIntegerRepresentation();
1087   bool RHSSigned = RHSType->hasSignedIntegerRepresentation();
1088   if (LHSSigned == RHSSigned) {
1089     // Same signedness; use the higher-ranked type
1090     if (order >= 0) {
1091       RHS = (*doRHSCast)(S, RHS.get(), LHSType);
1092       return LHSType;
1093     } else if (!IsCompAssign)
1094       LHS = (*doLHSCast)(S, LHS.get(), RHSType);
1095     return RHSType;
1096   } else if (order != (LHSSigned ? 1 : -1)) {
1097     // The unsigned type has greater than or equal rank to the
1098     // signed type, so use the unsigned type
1099     if (RHSSigned) {
1100       RHS = (*doRHSCast)(S, RHS.get(), LHSType);
1101       return LHSType;
1102     } else if (!IsCompAssign)
1103       LHS = (*doLHSCast)(S, LHS.get(), RHSType);
1104     return RHSType;
1105   } else if (S.Context.getIntWidth(LHSType) != S.Context.getIntWidth(RHSType)) {
1106     // The two types are different widths; if we are here, that
1107     // means the signed type is larger than the unsigned type, so
1108     // use the signed type.
1109     if (LHSSigned) {
1110       RHS = (*doRHSCast)(S, RHS.get(), LHSType);
1111       return LHSType;
1112     } else if (!IsCompAssign)
1113       LHS = (*doLHSCast)(S, LHS.get(), RHSType);
1114     return RHSType;
1115   } else {
1116     // The signed type is higher-ranked than the unsigned type,
1117     // but isn't actually any bigger (like unsigned int and long
1118     // on most 32-bit systems).  Use the unsigned type corresponding
1119     // to the signed type.
1120     QualType result =
1121       S.Context.getCorrespondingUnsignedType(LHSSigned ? LHSType : RHSType);
1122     RHS = (*doRHSCast)(S, RHS.get(), result);
1123     if (!IsCompAssign)
1124       LHS = (*doLHSCast)(S, LHS.get(), result);
1125     return result;
1126   }
1127 }
1128 
1129 /// \brief Handle conversions with GCC complex int extension.  Helper function
1130 /// of UsualArithmeticConversions()
handleComplexIntConversion(Sema & S,ExprResult & LHS,ExprResult & RHS,QualType LHSType,QualType RHSType,bool IsCompAssign)1131 static QualType handleComplexIntConversion(Sema &S, ExprResult &LHS,
1132                                            ExprResult &RHS, QualType LHSType,
1133                                            QualType RHSType,
1134                                            bool IsCompAssign) {
1135   const ComplexType *LHSComplexInt = LHSType->getAsComplexIntegerType();
1136   const ComplexType *RHSComplexInt = RHSType->getAsComplexIntegerType();
1137 
1138   if (LHSComplexInt && RHSComplexInt) {
1139     QualType LHSEltType = LHSComplexInt->getElementType();
1140     QualType RHSEltType = RHSComplexInt->getElementType();
1141     QualType ScalarType =
1142       handleIntegerConversion<doComplexIntegralCast, doComplexIntegralCast>
1143         (S, LHS, RHS, LHSEltType, RHSEltType, IsCompAssign);
1144 
1145     return S.Context.getComplexType(ScalarType);
1146   }
1147 
1148   if (LHSComplexInt) {
1149     QualType LHSEltType = LHSComplexInt->getElementType();
1150     QualType ScalarType =
1151       handleIntegerConversion<doComplexIntegralCast, doIntegralCast>
1152         (S, LHS, RHS, LHSEltType, RHSType, IsCompAssign);
1153     QualType ComplexType = S.Context.getComplexType(ScalarType);
1154     RHS = S.ImpCastExprToType(RHS.get(), ComplexType,
1155                               CK_IntegralRealToComplex);
1156 
1157     return ComplexType;
1158   }
1159 
1160   assert(RHSComplexInt);
1161 
1162   QualType RHSEltType = RHSComplexInt->getElementType();
1163   QualType ScalarType =
1164     handleIntegerConversion<doIntegralCast, doComplexIntegralCast>
1165       (S, LHS, RHS, LHSType, RHSEltType, IsCompAssign);
1166   QualType ComplexType = S.Context.getComplexType(ScalarType);
1167 
1168   if (!IsCompAssign)
1169     LHS = S.ImpCastExprToType(LHS.get(), ComplexType,
1170                               CK_IntegralRealToComplex);
1171   return ComplexType;
1172 }
1173 
1174 /// UsualArithmeticConversions - Performs various conversions that are common to
1175 /// binary operators (C99 6.3.1.8). If both operands aren't arithmetic, this
1176 /// routine returns the first non-arithmetic type found. The client is
1177 /// responsible for emitting appropriate error diagnostics.
UsualArithmeticConversions(ExprResult & LHS,ExprResult & RHS,bool IsCompAssign)1178 QualType Sema::UsualArithmeticConversions(ExprResult &LHS, ExprResult &RHS,
1179                                           bool IsCompAssign) {
1180   if (!IsCompAssign) {
1181     LHS = UsualUnaryConversions(LHS.get());
1182     if (LHS.isInvalid())
1183       return QualType();
1184   }
1185 
1186   RHS = UsualUnaryConversions(RHS.get());
1187   if (RHS.isInvalid())
1188     return QualType();
1189 
1190   // For conversion purposes, we ignore any qualifiers.
1191   // For example, "const float" and "float" are equivalent.
1192   QualType LHSType =
1193     Context.getCanonicalType(LHS.get()->getType()).getUnqualifiedType();
1194   QualType RHSType =
1195     Context.getCanonicalType(RHS.get()->getType()).getUnqualifiedType();
1196 
1197   // For conversion purposes, we ignore any atomic qualifier on the LHS.
1198   if (const AtomicType *AtomicLHS = LHSType->getAs<AtomicType>())
1199     LHSType = AtomicLHS->getValueType();
1200 
1201   // If both types are identical, no conversion is needed.
1202   if (LHSType == RHSType)
1203     return LHSType;
1204 
1205   // If either side is a non-arithmetic type (e.g. a pointer), we are done.
1206   // The caller can deal with this (e.g. pointer + int).
1207   if (!LHSType->isArithmeticType() || !RHSType->isArithmeticType())
1208     return QualType();
1209 
1210   // Apply unary and bitfield promotions to the LHS's type.
1211   QualType LHSUnpromotedType = LHSType;
1212   if (LHSType->isPromotableIntegerType())
1213     LHSType = Context.getPromotedIntegerType(LHSType);
1214   QualType LHSBitfieldPromoteTy = Context.isPromotableBitField(LHS.get());
1215   if (!LHSBitfieldPromoteTy.isNull())
1216     LHSType = LHSBitfieldPromoteTy;
1217   if (LHSType != LHSUnpromotedType && !IsCompAssign)
1218     LHS = ImpCastExprToType(LHS.get(), LHSType, CK_IntegralCast);
1219 
1220   // If both types are identical, no conversion is needed.
1221   if (LHSType == RHSType)
1222     return LHSType;
1223 
1224   // At this point, we have two different arithmetic types.
1225 
1226   // Handle complex types first (C99 6.3.1.8p1).
1227   if (LHSType->isComplexType() || RHSType->isComplexType())
1228     return handleComplexFloatConversion(*this, LHS, RHS, LHSType, RHSType,
1229                                         IsCompAssign);
1230 
1231   // Now handle "real" floating types (i.e. float, double, long double).
1232   if (LHSType->isRealFloatingType() || RHSType->isRealFloatingType())
1233     return handleFloatConversion(*this, LHS, RHS, LHSType, RHSType,
1234                                  IsCompAssign);
1235 
1236   // Handle GCC complex int extension.
1237   if (LHSType->isComplexIntegerType() || RHSType->isComplexIntegerType())
1238     return handleComplexIntConversion(*this, LHS, RHS, LHSType, RHSType,
1239                                       IsCompAssign);
1240 
1241   // Finally, we have two differing integer types.
1242   return handleIntegerConversion<doIntegralCast, doIntegralCast>
1243            (*this, LHS, RHS, LHSType, RHSType, IsCompAssign);
1244 }
1245 
1246 
1247 //===----------------------------------------------------------------------===//
1248 //  Semantic Analysis for various Expression Types
1249 //===----------------------------------------------------------------------===//
1250 
1251 
1252 ExprResult
ActOnGenericSelectionExpr(SourceLocation KeyLoc,SourceLocation DefaultLoc,SourceLocation RParenLoc,Expr * ControllingExpr,ArrayRef<ParsedType> ArgTypes,ArrayRef<Expr * > ArgExprs)1253 Sema::ActOnGenericSelectionExpr(SourceLocation KeyLoc,
1254                                 SourceLocation DefaultLoc,
1255                                 SourceLocation RParenLoc,
1256                                 Expr *ControllingExpr,
1257                                 ArrayRef<ParsedType> ArgTypes,
1258                                 ArrayRef<Expr *> ArgExprs) {
1259   unsigned NumAssocs = ArgTypes.size();
1260   assert(NumAssocs == ArgExprs.size());
1261 
1262   TypeSourceInfo **Types = new TypeSourceInfo*[NumAssocs];
1263   for (unsigned i = 0; i < NumAssocs; ++i) {
1264     if (ArgTypes[i])
1265       (void) GetTypeFromParser(ArgTypes[i], &Types[i]);
1266     else
1267       Types[i] = nullptr;
1268   }
1269 
1270   ExprResult ER = CreateGenericSelectionExpr(KeyLoc, DefaultLoc, RParenLoc,
1271                                              ControllingExpr,
1272                                              llvm::makeArrayRef(Types, NumAssocs),
1273                                              ArgExprs);
1274   delete [] Types;
1275   return ER;
1276 }
1277 
1278 ExprResult
CreateGenericSelectionExpr(SourceLocation KeyLoc,SourceLocation DefaultLoc,SourceLocation RParenLoc,Expr * ControllingExpr,ArrayRef<TypeSourceInfo * > Types,ArrayRef<Expr * > Exprs)1279 Sema::CreateGenericSelectionExpr(SourceLocation KeyLoc,
1280                                  SourceLocation DefaultLoc,
1281                                  SourceLocation RParenLoc,
1282                                  Expr *ControllingExpr,
1283                                  ArrayRef<TypeSourceInfo *> Types,
1284                                  ArrayRef<Expr *> Exprs) {
1285   unsigned NumAssocs = Types.size();
1286   assert(NumAssocs == Exprs.size());
1287   if (ControllingExpr->getType()->isPlaceholderType()) {
1288     ExprResult result = CheckPlaceholderExpr(ControllingExpr);
1289     if (result.isInvalid()) return ExprError();
1290     ControllingExpr = result.get();
1291   }
1292 
1293   // The controlling expression is an unevaluated operand, so side effects are
1294   // likely unintended.
1295   if (ActiveTemplateInstantiations.empty() &&
1296       ControllingExpr->HasSideEffects(Context, false))
1297     Diag(ControllingExpr->getExprLoc(),
1298          diag::warn_side_effects_unevaluated_context);
1299 
1300   bool TypeErrorFound = false,
1301        IsResultDependent = ControllingExpr->isTypeDependent(),
1302        ContainsUnexpandedParameterPack
1303          = ControllingExpr->containsUnexpandedParameterPack();
1304 
1305   for (unsigned i = 0; i < NumAssocs; ++i) {
1306     if (Exprs[i]->containsUnexpandedParameterPack())
1307       ContainsUnexpandedParameterPack = true;
1308 
1309     if (Types[i]) {
1310       if (Types[i]->getType()->containsUnexpandedParameterPack())
1311         ContainsUnexpandedParameterPack = true;
1312 
1313       if (Types[i]->getType()->isDependentType()) {
1314         IsResultDependent = true;
1315       } else {
1316         // C11 6.5.1.1p2 "The type name in a generic association shall specify a
1317         // complete object type other than a variably modified type."
1318         unsigned D = 0;
1319         if (Types[i]->getType()->isIncompleteType())
1320           D = diag::err_assoc_type_incomplete;
1321         else if (!Types[i]->getType()->isObjectType())
1322           D = diag::err_assoc_type_nonobject;
1323         else if (Types[i]->getType()->isVariablyModifiedType())
1324           D = diag::err_assoc_type_variably_modified;
1325 
1326         if (D != 0) {
1327           Diag(Types[i]->getTypeLoc().getBeginLoc(), D)
1328             << Types[i]->getTypeLoc().getSourceRange()
1329             << Types[i]->getType();
1330           TypeErrorFound = true;
1331         }
1332 
1333         // C11 6.5.1.1p2 "No two generic associations in the same generic
1334         // selection shall specify compatible types."
1335         for (unsigned j = i+1; j < NumAssocs; ++j)
1336           if (Types[j] && !Types[j]->getType()->isDependentType() &&
1337               Context.typesAreCompatible(Types[i]->getType(),
1338                                          Types[j]->getType())) {
1339             Diag(Types[j]->getTypeLoc().getBeginLoc(),
1340                  diag::err_assoc_compatible_types)
1341               << Types[j]->getTypeLoc().getSourceRange()
1342               << Types[j]->getType()
1343               << Types[i]->getType();
1344             Diag(Types[i]->getTypeLoc().getBeginLoc(),
1345                  diag::note_compat_assoc)
1346               << Types[i]->getTypeLoc().getSourceRange()
1347               << Types[i]->getType();
1348             TypeErrorFound = true;
1349           }
1350       }
1351     }
1352   }
1353   if (TypeErrorFound)
1354     return ExprError();
1355 
1356   // If we determined that the generic selection is result-dependent, don't
1357   // try to compute the result expression.
1358   if (IsResultDependent)
1359     return new (Context) GenericSelectionExpr(
1360         Context, KeyLoc, ControllingExpr, Types, Exprs, DefaultLoc, RParenLoc,
1361         ContainsUnexpandedParameterPack);
1362 
1363   SmallVector<unsigned, 1> CompatIndices;
1364   unsigned DefaultIndex = -1U;
1365   for (unsigned i = 0; i < NumAssocs; ++i) {
1366     if (!Types[i])
1367       DefaultIndex = i;
1368     else if (Context.typesAreCompatible(ControllingExpr->getType(),
1369                                         Types[i]->getType()))
1370       CompatIndices.push_back(i);
1371   }
1372 
1373   // C11 6.5.1.1p2 "The controlling expression of a generic selection shall have
1374   // type compatible with at most one of the types named in its generic
1375   // association list."
1376   if (CompatIndices.size() > 1) {
1377     // We strip parens here because the controlling expression is typically
1378     // parenthesized in macro definitions.
1379     ControllingExpr = ControllingExpr->IgnoreParens();
1380     Diag(ControllingExpr->getLocStart(), diag::err_generic_sel_multi_match)
1381       << ControllingExpr->getSourceRange() << ControllingExpr->getType()
1382       << (unsigned) CompatIndices.size();
1383     for (SmallVectorImpl<unsigned>::iterator I = CompatIndices.begin(),
1384          E = CompatIndices.end(); I != E; ++I) {
1385       Diag(Types[*I]->getTypeLoc().getBeginLoc(),
1386            diag::note_compat_assoc)
1387         << Types[*I]->getTypeLoc().getSourceRange()
1388         << Types[*I]->getType();
1389     }
1390     return ExprError();
1391   }
1392 
1393   // C11 6.5.1.1p2 "If a generic selection has no default generic association,
1394   // its controlling expression shall have type compatible with exactly one of
1395   // the types named in its generic association list."
1396   if (DefaultIndex == -1U && CompatIndices.size() == 0) {
1397     // We strip parens here because the controlling expression is typically
1398     // parenthesized in macro definitions.
1399     ControllingExpr = ControllingExpr->IgnoreParens();
1400     Diag(ControllingExpr->getLocStart(), diag::err_generic_sel_no_match)
1401       << ControllingExpr->getSourceRange() << ControllingExpr->getType();
1402     return ExprError();
1403   }
1404 
1405   // C11 6.5.1.1p3 "If a generic selection has a generic association with a
1406   // type name that is compatible with the type of the controlling expression,
1407   // then the result expression of the generic selection is the expression
1408   // in that generic association. Otherwise, the result expression of the
1409   // generic selection is the expression in the default generic association."
1410   unsigned ResultIndex =
1411     CompatIndices.size() ? CompatIndices[0] : DefaultIndex;
1412 
1413   return new (Context) GenericSelectionExpr(
1414       Context, KeyLoc, ControllingExpr, Types, Exprs, DefaultLoc, RParenLoc,
1415       ContainsUnexpandedParameterPack, ResultIndex);
1416 }
1417 
1418 /// getUDSuffixLoc - Create a SourceLocation for a ud-suffix, given the
1419 /// location of the token and the offset of the ud-suffix within it.
getUDSuffixLoc(Sema & S,SourceLocation TokLoc,unsigned Offset)1420 static SourceLocation getUDSuffixLoc(Sema &S, SourceLocation TokLoc,
1421                                      unsigned Offset) {
1422   return Lexer::AdvanceToTokenCharacter(TokLoc, Offset, S.getSourceManager(),
1423                                         S.getLangOpts());
1424 }
1425 
1426 /// BuildCookedLiteralOperatorCall - A user-defined literal was found. Look up
1427 /// the corresponding cooked (non-raw) literal operator, and build a call to it.
BuildCookedLiteralOperatorCall(Sema & S,Scope * Scope,IdentifierInfo * UDSuffix,SourceLocation UDSuffixLoc,ArrayRef<Expr * > Args,SourceLocation LitEndLoc)1428 static ExprResult BuildCookedLiteralOperatorCall(Sema &S, Scope *Scope,
1429                                                  IdentifierInfo *UDSuffix,
1430                                                  SourceLocation UDSuffixLoc,
1431                                                  ArrayRef<Expr*> Args,
1432                                                  SourceLocation LitEndLoc) {
1433   assert(Args.size() <= 2 && "too many arguments for literal operator");
1434 
1435   QualType ArgTy[2];
1436   for (unsigned ArgIdx = 0; ArgIdx != Args.size(); ++ArgIdx) {
1437     ArgTy[ArgIdx] = Args[ArgIdx]->getType();
1438     if (ArgTy[ArgIdx]->isArrayType())
1439       ArgTy[ArgIdx] = S.Context.getArrayDecayedType(ArgTy[ArgIdx]);
1440   }
1441 
1442   DeclarationName OpName =
1443     S.Context.DeclarationNames.getCXXLiteralOperatorName(UDSuffix);
1444   DeclarationNameInfo OpNameInfo(OpName, UDSuffixLoc);
1445   OpNameInfo.setCXXLiteralOperatorNameLoc(UDSuffixLoc);
1446 
1447   LookupResult R(S, OpName, UDSuffixLoc, Sema::LookupOrdinaryName);
1448   if (S.LookupLiteralOperator(Scope, R, llvm::makeArrayRef(ArgTy, Args.size()),
1449                               /*AllowRaw*/false, /*AllowTemplate*/false,
1450                               /*AllowStringTemplate*/false) == Sema::LOLR_Error)
1451     return ExprError();
1452 
1453   return S.BuildLiteralOperatorCall(R, OpNameInfo, Args, LitEndLoc);
1454 }
1455 
1456 /// ActOnStringLiteral - The specified tokens were lexed as pasted string
1457 /// fragments (e.g. "foo" "bar" L"baz").  The result string has to handle string
1458 /// concatenation ([C99 5.1.1.2, translation phase #6]), so it may come from
1459 /// multiple tokens.  However, the common case is that StringToks points to one
1460 /// string.
1461 ///
1462 ExprResult
ActOnStringLiteral(ArrayRef<Token> StringToks,Scope * UDLScope)1463 Sema::ActOnStringLiteral(ArrayRef<Token> StringToks, Scope *UDLScope) {
1464   assert(!StringToks.empty() && "Must have at least one string!");
1465 
1466   StringLiteralParser Literal(StringToks, PP);
1467   if (Literal.hadError)
1468     return ExprError();
1469 
1470   SmallVector<SourceLocation, 4> StringTokLocs;
1471   for (unsigned i = 0; i != StringToks.size(); ++i)
1472     StringTokLocs.push_back(StringToks[i].getLocation());
1473 
1474   QualType CharTy = Context.CharTy;
1475   StringLiteral::StringKind Kind = StringLiteral::Ascii;
1476   if (Literal.isWide()) {
1477     CharTy = Context.getWideCharType();
1478     Kind = StringLiteral::Wide;
1479   } else if (Literal.isUTF8()) {
1480     Kind = StringLiteral::UTF8;
1481   } else if (Literal.isUTF16()) {
1482     CharTy = Context.Char16Ty;
1483     Kind = StringLiteral::UTF16;
1484   } else if (Literal.isUTF32()) {
1485     CharTy = Context.Char32Ty;
1486     Kind = StringLiteral::UTF32;
1487   } else if (Literal.isPascal()) {
1488     CharTy = Context.UnsignedCharTy;
1489   }
1490 
1491   QualType CharTyConst = CharTy;
1492   // A C++ string literal has a const-qualified element type (C++ 2.13.4p1).
1493   if (getLangOpts().CPlusPlus || getLangOpts().ConstStrings)
1494     CharTyConst.addConst();
1495 
1496   // Get an array type for the string, according to C99 6.4.5.  This includes
1497   // the nul terminator character as well as the string length for pascal
1498   // strings.
1499   QualType StrTy = Context.getConstantArrayType(CharTyConst,
1500                                  llvm::APInt(32, Literal.GetNumStringChars()+1),
1501                                  ArrayType::Normal, 0);
1502 
1503   // OpenCL v1.1 s6.5.3: a string literal is in the constant address space.
1504   if (getLangOpts().OpenCL) {
1505     StrTy = Context.getAddrSpaceQualType(StrTy, LangAS::opencl_constant);
1506   }
1507 
1508   // Pass &StringTokLocs[0], StringTokLocs.size() to factory!
1509   StringLiteral *Lit = StringLiteral::Create(Context, Literal.GetString(),
1510                                              Kind, Literal.Pascal, StrTy,
1511                                              &StringTokLocs[0],
1512                                              StringTokLocs.size());
1513   if (Literal.getUDSuffix().empty())
1514     return Lit;
1515 
1516   // We're building a user-defined literal.
1517   IdentifierInfo *UDSuffix = &Context.Idents.get(Literal.getUDSuffix());
1518   SourceLocation UDSuffixLoc =
1519     getUDSuffixLoc(*this, StringTokLocs[Literal.getUDSuffixToken()],
1520                    Literal.getUDSuffixOffset());
1521 
1522   // Make sure we're allowed user-defined literals here.
1523   if (!UDLScope)
1524     return ExprError(Diag(UDSuffixLoc, diag::err_invalid_string_udl));
1525 
1526   // C++11 [lex.ext]p5: The literal L is treated as a call of the form
1527   //   operator "" X (str, len)
1528   QualType SizeType = Context.getSizeType();
1529 
1530   DeclarationName OpName =
1531     Context.DeclarationNames.getCXXLiteralOperatorName(UDSuffix);
1532   DeclarationNameInfo OpNameInfo(OpName, UDSuffixLoc);
1533   OpNameInfo.setCXXLiteralOperatorNameLoc(UDSuffixLoc);
1534 
1535   QualType ArgTy[] = {
1536     Context.getArrayDecayedType(StrTy), SizeType
1537   };
1538 
1539   LookupResult R(*this, OpName, UDSuffixLoc, LookupOrdinaryName);
1540   switch (LookupLiteralOperator(UDLScope, R, ArgTy,
1541                                 /*AllowRaw*/false, /*AllowTemplate*/false,
1542                                 /*AllowStringTemplate*/true)) {
1543 
1544   case LOLR_Cooked: {
1545     llvm::APInt Len(Context.getIntWidth(SizeType), Literal.GetNumStringChars());
1546     IntegerLiteral *LenArg = IntegerLiteral::Create(Context, Len, SizeType,
1547                                                     StringTokLocs[0]);
1548     Expr *Args[] = { Lit, LenArg };
1549 
1550     return BuildLiteralOperatorCall(R, OpNameInfo, Args, StringTokLocs.back());
1551   }
1552 
1553   case LOLR_StringTemplate: {
1554     TemplateArgumentListInfo ExplicitArgs;
1555 
1556     unsigned CharBits = Context.getIntWidth(CharTy);
1557     bool CharIsUnsigned = CharTy->isUnsignedIntegerType();
1558     llvm::APSInt Value(CharBits, CharIsUnsigned);
1559 
1560     TemplateArgument TypeArg(CharTy);
1561     TemplateArgumentLocInfo TypeArgInfo(Context.getTrivialTypeSourceInfo(CharTy));
1562     ExplicitArgs.addArgument(TemplateArgumentLoc(TypeArg, TypeArgInfo));
1563 
1564     for (unsigned I = 0, N = Lit->getLength(); I != N; ++I) {
1565       Value = Lit->getCodeUnit(I);
1566       TemplateArgument Arg(Context, Value, CharTy);
1567       TemplateArgumentLocInfo ArgInfo;
1568       ExplicitArgs.addArgument(TemplateArgumentLoc(Arg, ArgInfo));
1569     }
1570     return BuildLiteralOperatorCall(R, OpNameInfo, None, StringTokLocs.back(),
1571                                     &ExplicitArgs);
1572   }
1573   case LOLR_Raw:
1574   case LOLR_Template:
1575     llvm_unreachable("unexpected literal operator lookup result");
1576   case LOLR_Error:
1577     return ExprError();
1578   }
1579   llvm_unreachable("unexpected literal operator lookup result");
1580 }
1581 
1582 ExprResult
BuildDeclRefExpr(ValueDecl * D,QualType Ty,ExprValueKind VK,SourceLocation Loc,const CXXScopeSpec * SS)1583 Sema::BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
1584                        SourceLocation Loc,
1585                        const CXXScopeSpec *SS) {
1586   DeclarationNameInfo NameInfo(D->getDeclName(), Loc);
1587   return BuildDeclRefExpr(D, Ty, VK, NameInfo, SS);
1588 }
1589 
1590 /// BuildDeclRefExpr - Build an expression that references a
1591 /// declaration that does not require a closure capture.
1592 ExprResult
BuildDeclRefExpr(ValueDecl * D,QualType Ty,ExprValueKind VK,const DeclarationNameInfo & NameInfo,const CXXScopeSpec * SS,NamedDecl * FoundD,const TemplateArgumentListInfo * TemplateArgs)1593 Sema::BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
1594                        const DeclarationNameInfo &NameInfo,
1595                        const CXXScopeSpec *SS, NamedDecl *FoundD,
1596                        const TemplateArgumentListInfo *TemplateArgs) {
1597   if (getLangOpts().CUDA)
1598     if (const FunctionDecl *Caller = dyn_cast<FunctionDecl>(CurContext))
1599       if (const FunctionDecl *Callee = dyn_cast<FunctionDecl>(D)) {
1600         if (CheckCUDATarget(Caller, Callee)) {
1601           Diag(NameInfo.getLoc(), diag::err_ref_bad_target)
1602             << IdentifyCUDATarget(Callee) << D->getIdentifier()
1603             << IdentifyCUDATarget(Caller);
1604           Diag(D->getLocation(), diag::note_previous_decl)
1605             << D->getIdentifier();
1606           return ExprError();
1607         }
1608       }
1609 
1610   bool RefersToCapturedVariable =
1611       isa<VarDecl>(D) &&
1612       NeedToCaptureVariable(cast<VarDecl>(D), NameInfo.getLoc());
1613 
1614   DeclRefExpr *E;
1615   if (isa<VarTemplateSpecializationDecl>(D)) {
1616     VarTemplateSpecializationDecl *VarSpec =
1617         cast<VarTemplateSpecializationDecl>(D);
1618 
1619     E = DeclRefExpr::Create(Context, SS ? SS->getWithLocInContext(Context)
1620                                         : NestedNameSpecifierLoc(),
1621                             VarSpec->getTemplateKeywordLoc(), D,
1622                             RefersToCapturedVariable, NameInfo.getLoc(), Ty, VK,
1623                             FoundD, TemplateArgs);
1624   } else {
1625     assert(!TemplateArgs && "No template arguments for non-variable"
1626                             " template specialization references");
1627     E = DeclRefExpr::Create(Context, SS ? SS->getWithLocInContext(Context)
1628                                         : NestedNameSpecifierLoc(),
1629                             SourceLocation(), D, RefersToCapturedVariable,
1630                             NameInfo, Ty, VK, FoundD);
1631   }
1632 
1633   MarkDeclRefReferenced(E);
1634 
1635   if (getLangOpts().ObjCARCWeak && isa<VarDecl>(D) &&
1636       Ty.getObjCLifetime() == Qualifiers::OCL_Weak &&
1637       !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, E->getLocStart()))
1638       recordUseOfEvaluatedWeak(E);
1639 
1640   // Just in case we're building an illegal pointer-to-member.
1641   FieldDecl *FD = dyn_cast<FieldDecl>(D);
1642   if (FD && FD->isBitField())
1643     E->setObjectKind(OK_BitField);
1644 
1645   return E;
1646 }
1647 
1648 /// Decomposes the given name into a DeclarationNameInfo, its location, and
1649 /// possibly a list of template arguments.
1650 ///
1651 /// If this produces template arguments, it is permitted to call
1652 /// DecomposeTemplateName.
1653 ///
1654 /// This actually loses a lot of source location information for
1655 /// non-standard name kinds; we should consider preserving that in
1656 /// some way.
1657 void
DecomposeUnqualifiedId(const UnqualifiedId & Id,TemplateArgumentListInfo & Buffer,DeclarationNameInfo & NameInfo,const TemplateArgumentListInfo * & TemplateArgs)1658 Sema::DecomposeUnqualifiedId(const UnqualifiedId &Id,
1659                              TemplateArgumentListInfo &Buffer,
1660                              DeclarationNameInfo &NameInfo,
1661                              const TemplateArgumentListInfo *&TemplateArgs) {
1662   if (Id.getKind() == UnqualifiedId::IK_TemplateId) {
1663     Buffer.setLAngleLoc(Id.TemplateId->LAngleLoc);
1664     Buffer.setRAngleLoc(Id.TemplateId->RAngleLoc);
1665 
1666     ASTTemplateArgsPtr TemplateArgsPtr(Id.TemplateId->getTemplateArgs(),
1667                                        Id.TemplateId->NumArgs);
1668     translateTemplateArguments(TemplateArgsPtr, Buffer);
1669 
1670     TemplateName TName = Id.TemplateId->Template.get();
1671     SourceLocation TNameLoc = Id.TemplateId->TemplateNameLoc;
1672     NameInfo = Context.getNameForTemplate(TName, TNameLoc);
1673     TemplateArgs = &Buffer;
1674   } else {
1675     NameInfo = GetNameFromUnqualifiedId(Id);
1676     TemplateArgs = nullptr;
1677   }
1678 }
1679 
emitEmptyLookupTypoDiagnostic(const TypoCorrection & TC,Sema & SemaRef,const CXXScopeSpec & SS,DeclarationName Typo,SourceLocation TypoLoc,ArrayRef<Expr * > Args,unsigned DiagnosticID,unsigned DiagnosticSuggestID)1680 static void emitEmptyLookupTypoDiagnostic(
1681     const TypoCorrection &TC, Sema &SemaRef, const CXXScopeSpec &SS,
1682     DeclarationName Typo, SourceLocation TypoLoc, ArrayRef<Expr *> Args,
1683     unsigned DiagnosticID, unsigned DiagnosticSuggestID) {
1684   DeclContext *Ctx =
1685       SS.isEmpty() ? nullptr : SemaRef.computeDeclContext(SS, false);
1686   if (!TC) {
1687     // Emit a special diagnostic for failed member lookups.
1688     // FIXME: computing the declaration context might fail here (?)
1689     if (Ctx)
1690       SemaRef.Diag(TypoLoc, diag::err_no_member) << Typo << Ctx
1691                                                  << SS.getRange();
1692     else
1693       SemaRef.Diag(TypoLoc, DiagnosticID) << Typo;
1694     return;
1695   }
1696 
1697   std::string CorrectedStr = TC.getAsString(SemaRef.getLangOpts());
1698   bool DroppedSpecifier =
1699       TC.WillReplaceSpecifier() && Typo.getAsString() == CorrectedStr;
1700   unsigned NoteID =
1701       (TC.getCorrectionDecl() && isa<ImplicitParamDecl>(TC.getCorrectionDecl()))
1702           ? diag::note_implicit_param_decl
1703           : diag::note_previous_decl;
1704   if (!Ctx)
1705     SemaRef.diagnoseTypo(TC, SemaRef.PDiag(DiagnosticSuggestID) << Typo,
1706                          SemaRef.PDiag(NoteID));
1707   else
1708     SemaRef.diagnoseTypo(TC, SemaRef.PDiag(diag::err_no_member_suggest)
1709                                  << Typo << Ctx << DroppedSpecifier
1710                                  << SS.getRange(),
1711                          SemaRef.PDiag(NoteID));
1712 }
1713 
1714 /// Diagnose an empty lookup.
1715 ///
1716 /// \return false if new lookup candidates were found
1717 bool
DiagnoseEmptyLookup(Scope * S,CXXScopeSpec & SS,LookupResult & R,std::unique_ptr<CorrectionCandidateCallback> CCC,TemplateArgumentListInfo * ExplicitTemplateArgs,ArrayRef<Expr * > Args,TypoExpr ** Out)1718 Sema::DiagnoseEmptyLookup(Scope *S, CXXScopeSpec &SS, LookupResult &R,
1719                           std::unique_ptr<CorrectionCandidateCallback> CCC,
1720                           TemplateArgumentListInfo *ExplicitTemplateArgs,
1721                           ArrayRef<Expr *> Args, TypoExpr **Out) {
1722   DeclarationName Name = R.getLookupName();
1723 
1724   unsigned diagnostic = diag::err_undeclared_var_use;
1725   unsigned diagnostic_suggest = diag::err_undeclared_var_use_suggest;
1726   if (Name.getNameKind() == DeclarationName::CXXOperatorName ||
1727       Name.getNameKind() == DeclarationName::CXXLiteralOperatorName ||
1728       Name.getNameKind() == DeclarationName::CXXConversionFunctionName) {
1729     diagnostic = diag::err_undeclared_use;
1730     diagnostic_suggest = diag::err_undeclared_use_suggest;
1731   }
1732 
1733   // If the original lookup was an unqualified lookup, fake an
1734   // unqualified lookup.  This is useful when (for example) the
1735   // original lookup would not have found something because it was a
1736   // dependent name.
1737   DeclContext *DC = (SS.isEmpty() && !CallsUndergoingInstantiation.empty())
1738     ? CurContext : nullptr;
1739   while (DC) {
1740     if (isa<CXXRecordDecl>(DC)) {
1741       LookupQualifiedName(R, DC);
1742 
1743       if (!R.empty()) {
1744         // Don't give errors about ambiguities in this lookup.
1745         R.suppressDiagnostics();
1746 
1747         // During a default argument instantiation the CurContext points
1748         // to a CXXMethodDecl; but we can't apply a this-> fixit inside a
1749         // function parameter list, hence add an explicit check.
1750         bool isDefaultArgument = !ActiveTemplateInstantiations.empty() &&
1751                               ActiveTemplateInstantiations.back().Kind ==
1752             ActiveTemplateInstantiation::DefaultFunctionArgumentInstantiation;
1753         CXXMethodDecl *CurMethod = dyn_cast<CXXMethodDecl>(CurContext);
1754         bool isInstance = CurMethod &&
1755                           CurMethod->isInstance() &&
1756                           DC == CurMethod->getParent() && !isDefaultArgument;
1757 
1758 
1759         // Give a code modification hint to insert 'this->'.
1760         // TODO: fixit for inserting 'Base<T>::' in the other cases.
1761         // Actually quite difficult!
1762         if (getLangOpts().MSVCCompat)
1763           diagnostic = diag::ext_found_via_dependent_bases_lookup;
1764         if (isInstance) {
1765           Diag(R.getNameLoc(), diagnostic) << Name
1766             << FixItHint::CreateInsertion(R.getNameLoc(), "this->");
1767           UnresolvedLookupExpr *ULE = cast<UnresolvedLookupExpr>(
1768               CallsUndergoingInstantiation.back()->getCallee());
1769 
1770           CXXMethodDecl *DepMethod;
1771           if (CurMethod->isDependentContext())
1772             DepMethod = CurMethod;
1773           else if (CurMethod->getTemplatedKind() ==
1774               FunctionDecl::TK_FunctionTemplateSpecialization)
1775             DepMethod = cast<CXXMethodDecl>(CurMethod->getPrimaryTemplate()->
1776                 getInstantiatedFromMemberTemplate()->getTemplatedDecl());
1777           else
1778             DepMethod = cast<CXXMethodDecl>(
1779                 CurMethod->getInstantiatedFromMemberFunction());
1780           assert(DepMethod && "No template pattern found");
1781 
1782           QualType DepThisType = DepMethod->getThisType(Context);
1783           CheckCXXThisCapture(R.getNameLoc());
1784           CXXThisExpr *DepThis = new (Context) CXXThisExpr(
1785                                      R.getNameLoc(), DepThisType, false);
1786           TemplateArgumentListInfo TList;
1787           if (ULE->hasExplicitTemplateArgs())
1788             ULE->copyTemplateArgumentsInto(TList);
1789 
1790           CXXScopeSpec SS;
1791           SS.Adopt(ULE->getQualifierLoc());
1792           CXXDependentScopeMemberExpr *DepExpr =
1793               CXXDependentScopeMemberExpr::Create(
1794                   Context, DepThis, DepThisType, true, SourceLocation(),
1795                   SS.getWithLocInContext(Context),
1796                   ULE->getTemplateKeywordLoc(), nullptr,
1797                   R.getLookupNameInfo(),
1798                   ULE->hasExplicitTemplateArgs() ? &TList : nullptr);
1799           CallsUndergoingInstantiation.back()->setCallee(DepExpr);
1800         } else {
1801           Diag(R.getNameLoc(), diagnostic) << Name;
1802         }
1803 
1804         // Do we really want to note all of these?
1805         for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I)
1806           Diag((*I)->getLocation(), diag::note_dependent_var_use);
1807 
1808         // Return true if we are inside a default argument instantiation
1809         // and the found name refers to an instance member function, otherwise
1810         // the function calling DiagnoseEmptyLookup will try to create an
1811         // implicit member call and this is wrong for default argument.
1812         if (isDefaultArgument && ((*R.begin())->isCXXInstanceMember())) {
1813           Diag(R.getNameLoc(), diag::err_member_call_without_object);
1814           return true;
1815         }
1816 
1817         // Tell the callee to try to recover.
1818         return false;
1819       }
1820 
1821       R.clear();
1822     }
1823 
1824     // In Microsoft mode, if we are performing lookup from within a friend
1825     // function definition declared at class scope then we must set
1826     // DC to the lexical parent to be able to search into the parent
1827     // class.
1828     if (getLangOpts().MSVCCompat && isa<FunctionDecl>(DC) &&
1829         cast<FunctionDecl>(DC)->getFriendObjectKind() &&
1830         DC->getLexicalParent()->isRecord())
1831       DC = DC->getLexicalParent();
1832     else
1833       DC = DC->getParent();
1834   }
1835 
1836   // We didn't find anything, so try to correct for a typo.
1837   TypoCorrection Corrected;
1838   if (S && Out) {
1839     SourceLocation TypoLoc = R.getNameLoc();
1840     assert(!ExplicitTemplateArgs &&
1841            "Diagnosing an empty lookup with explicit template args!");
1842     *Out = CorrectTypoDelayed(
1843         R.getLookupNameInfo(), R.getLookupKind(), S, &SS, std::move(CCC),
1844         [=](const TypoCorrection &TC) {
1845           emitEmptyLookupTypoDiagnostic(TC, *this, SS, Name, TypoLoc, Args,
1846                                         diagnostic, diagnostic_suggest);
1847         },
1848         nullptr, CTK_ErrorRecovery);
1849     if (*Out)
1850       return true;
1851   } else if (S && (Corrected =
1852                        CorrectTypo(R.getLookupNameInfo(), R.getLookupKind(), S,
1853                                    &SS, std::move(CCC), CTK_ErrorRecovery))) {
1854     std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
1855     bool DroppedSpecifier =
1856         Corrected.WillReplaceSpecifier() && Name.getAsString() == CorrectedStr;
1857     R.setLookupName(Corrected.getCorrection());
1858 
1859     bool AcceptableWithRecovery = false;
1860     bool AcceptableWithoutRecovery = false;
1861     NamedDecl *ND = Corrected.getCorrectionDecl();
1862     if (ND) {
1863       if (Corrected.isOverloaded()) {
1864         OverloadCandidateSet OCS(R.getNameLoc(),
1865                                  OverloadCandidateSet::CSK_Normal);
1866         OverloadCandidateSet::iterator Best;
1867         for (TypoCorrection::decl_iterator CD = Corrected.begin(),
1868                                         CDEnd = Corrected.end();
1869              CD != CDEnd; ++CD) {
1870           if (FunctionTemplateDecl *FTD =
1871                    dyn_cast<FunctionTemplateDecl>(*CD))
1872             AddTemplateOverloadCandidate(
1873                 FTD, DeclAccessPair::make(FTD, AS_none), ExplicitTemplateArgs,
1874                 Args, OCS);
1875           else if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*CD))
1876             if (!ExplicitTemplateArgs || ExplicitTemplateArgs->size() == 0)
1877               AddOverloadCandidate(FD, DeclAccessPair::make(FD, AS_none),
1878                                    Args, OCS);
1879         }
1880         switch (OCS.BestViableFunction(*this, R.getNameLoc(), Best)) {
1881         case OR_Success:
1882           ND = Best->Function;
1883           Corrected.setCorrectionDecl(ND);
1884           break;
1885         default:
1886           // FIXME: Arbitrarily pick the first declaration for the note.
1887           Corrected.setCorrectionDecl(ND);
1888           break;
1889         }
1890       }
1891       R.addDecl(ND);
1892       if (getLangOpts().CPlusPlus && ND->isCXXClassMember()) {
1893         CXXRecordDecl *Record = nullptr;
1894         if (Corrected.getCorrectionSpecifier()) {
1895           const Type *Ty = Corrected.getCorrectionSpecifier()->getAsType();
1896           Record = Ty->getAsCXXRecordDecl();
1897         }
1898         if (!Record)
1899           Record = cast<CXXRecordDecl>(
1900               ND->getDeclContext()->getRedeclContext());
1901         R.setNamingClass(Record);
1902       }
1903 
1904       AcceptableWithRecovery =
1905           isa<ValueDecl>(ND) || isa<FunctionTemplateDecl>(ND);
1906       // FIXME: If we ended up with a typo for a type name or
1907       // Objective-C class name, we're in trouble because the parser
1908       // is in the wrong place to recover. Suggest the typo
1909       // correction, but don't make it a fix-it since we're not going
1910       // to recover well anyway.
1911       AcceptableWithoutRecovery =
1912           isa<TypeDecl>(ND) || isa<ObjCInterfaceDecl>(ND);
1913     } else {
1914       // FIXME: We found a keyword. Suggest it, but don't provide a fix-it
1915       // because we aren't able to recover.
1916       AcceptableWithoutRecovery = true;
1917     }
1918 
1919     if (AcceptableWithRecovery || AcceptableWithoutRecovery) {
1920       unsigned NoteID = (Corrected.getCorrectionDecl() &&
1921                          isa<ImplicitParamDecl>(Corrected.getCorrectionDecl()))
1922                             ? diag::note_implicit_param_decl
1923                             : diag::note_previous_decl;
1924       if (SS.isEmpty())
1925         diagnoseTypo(Corrected, PDiag(diagnostic_suggest) << Name,
1926                      PDiag(NoteID), AcceptableWithRecovery);
1927       else
1928         diagnoseTypo(Corrected, PDiag(diag::err_no_member_suggest)
1929                                   << Name << computeDeclContext(SS, false)
1930                                   << DroppedSpecifier << SS.getRange(),
1931                      PDiag(NoteID), AcceptableWithRecovery);
1932 
1933       // Tell the callee whether to try to recover.
1934       return !AcceptableWithRecovery;
1935     }
1936   }
1937   R.clear();
1938 
1939   // Emit a special diagnostic for failed member lookups.
1940   // FIXME: computing the declaration context might fail here (?)
1941   if (!SS.isEmpty()) {
1942     Diag(R.getNameLoc(), diag::err_no_member)
1943       << Name << computeDeclContext(SS, false)
1944       << SS.getRange();
1945     return true;
1946   }
1947 
1948   // Give up, we can't recover.
1949   Diag(R.getNameLoc(), diagnostic) << Name;
1950   return true;
1951 }
1952 
1953 /// In Microsoft mode, if we are inside a template class whose parent class has
1954 /// dependent base classes, and we can't resolve an unqualified identifier, then
1955 /// assume the identifier is a member of a dependent base class.  We can only
1956 /// recover successfully in static methods, instance methods, and other contexts
1957 /// where 'this' is available.  This doesn't precisely match MSVC's
1958 /// instantiation model, but it's close enough.
1959 static Expr *
recoverFromMSUnqualifiedLookup(Sema & S,ASTContext & Context,DeclarationNameInfo & NameInfo,SourceLocation TemplateKWLoc,const TemplateArgumentListInfo * TemplateArgs)1960 recoverFromMSUnqualifiedLookup(Sema &S, ASTContext &Context,
1961                                DeclarationNameInfo &NameInfo,
1962                                SourceLocation TemplateKWLoc,
1963                                const TemplateArgumentListInfo *TemplateArgs) {
1964   // Only try to recover from lookup into dependent bases in static methods or
1965   // contexts where 'this' is available.
1966   QualType ThisType = S.getCurrentThisType();
1967   const CXXRecordDecl *RD = nullptr;
1968   if (!ThisType.isNull())
1969     RD = ThisType->getPointeeType()->getAsCXXRecordDecl();
1970   else if (auto *MD = dyn_cast<CXXMethodDecl>(S.CurContext))
1971     RD = MD->getParent();
1972   if (!RD || !RD->hasAnyDependentBases())
1973     return nullptr;
1974 
1975   // Diagnose this as unqualified lookup into a dependent base class.  If 'this'
1976   // is available, suggest inserting 'this->' as a fixit.
1977   SourceLocation Loc = NameInfo.getLoc();
1978   auto DB = S.Diag(Loc, diag::ext_undeclared_unqual_id_with_dependent_base);
1979   DB << NameInfo.getName() << RD;
1980 
1981   if (!ThisType.isNull()) {
1982     DB << FixItHint::CreateInsertion(Loc, "this->");
1983     return CXXDependentScopeMemberExpr::Create(
1984         Context, /*This=*/nullptr, ThisType, /*IsArrow=*/true,
1985         /*Op=*/SourceLocation(), NestedNameSpecifierLoc(), TemplateKWLoc,
1986         /*FirstQualifierInScope=*/nullptr, NameInfo, TemplateArgs);
1987   }
1988 
1989   // Synthesize a fake NNS that points to the derived class.  This will
1990   // perform name lookup during template instantiation.
1991   CXXScopeSpec SS;
1992   auto *NNS =
1993       NestedNameSpecifier::Create(Context, nullptr, true, RD->getTypeForDecl());
1994   SS.MakeTrivial(Context, NNS, SourceRange(Loc, Loc));
1995   return DependentScopeDeclRefExpr::Create(
1996       Context, SS.getWithLocInContext(Context), TemplateKWLoc, NameInfo,
1997       TemplateArgs);
1998 }
1999 
2000 ExprResult
ActOnIdExpression(Scope * S,CXXScopeSpec & SS,SourceLocation TemplateKWLoc,UnqualifiedId & Id,bool HasTrailingLParen,bool IsAddressOfOperand,std::unique_ptr<CorrectionCandidateCallback> CCC,bool IsInlineAsmIdentifier,Token * KeywordReplacement)2001 Sema::ActOnIdExpression(Scope *S, CXXScopeSpec &SS,
2002                         SourceLocation TemplateKWLoc, UnqualifiedId &Id,
2003                         bool HasTrailingLParen, bool IsAddressOfOperand,
2004                         std::unique_ptr<CorrectionCandidateCallback> CCC,
2005                         bool IsInlineAsmIdentifier, Token *KeywordReplacement) {
2006   assert(!(IsAddressOfOperand && HasTrailingLParen) &&
2007          "cannot be direct & operand and have a trailing lparen");
2008   if (SS.isInvalid())
2009     return ExprError();
2010 
2011   TemplateArgumentListInfo TemplateArgsBuffer;
2012 
2013   // Decompose the UnqualifiedId into the following data.
2014   DeclarationNameInfo NameInfo;
2015   const TemplateArgumentListInfo *TemplateArgs;
2016   DecomposeUnqualifiedId(Id, TemplateArgsBuffer, NameInfo, TemplateArgs);
2017 
2018   DeclarationName Name = NameInfo.getName();
2019   IdentifierInfo *II = Name.getAsIdentifierInfo();
2020   SourceLocation NameLoc = NameInfo.getLoc();
2021 
2022   // C++ [temp.dep.expr]p3:
2023   //   An id-expression is type-dependent if it contains:
2024   //     -- an identifier that was declared with a dependent type,
2025   //        (note: handled after lookup)
2026   //     -- a template-id that is dependent,
2027   //        (note: handled in BuildTemplateIdExpr)
2028   //     -- a conversion-function-id that specifies a dependent type,
2029   //     -- a nested-name-specifier that contains a class-name that
2030   //        names a dependent type.
2031   // Determine whether this is a member of an unknown specialization;
2032   // we need to handle these differently.
2033   bool DependentID = false;
2034   if (Name.getNameKind() == DeclarationName::CXXConversionFunctionName &&
2035       Name.getCXXNameType()->isDependentType()) {
2036     DependentID = true;
2037   } else if (SS.isSet()) {
2038     if (DeclContext *DC = computeDeclContext(SS, false)) {
2039       if (RequireCompleteDeclContext(SS, DC))
2040         return ExprError();
2041     } else {
2042       DependentID = true;
2043     }
2044   }
2045 
2046   if (DependentID)
2047     return ActOnDependentIdExpression(SS, TemplateKWLoc, NameInfo,
2048                                       IsAddressOfOperand, TemplateArgs);
2049 
2050   // Perform the required lookup.
2051   LookupResult R(*this, NameInfo,
2052                  (Id.getKind() == UnqualifiedId::IK_ImplicitSelfParam)
2053                   ? LookupObjCImplicitSelfParam : LookupOrdinaryName);
2054   if (TemplateArgs) {
2055     // Lookup the template name again to correctly establish the context in
2056     // which it was found. This is really unfortunate as we already did the
2057     // lookup to determine that it was a template name in the first place. If
2058     // this becomes a performance hit, we can work harder to preserve those
2059     // results until we get here but it's likely not worth it.
2060     bool MemberOfUnknownSpecialization;
2061     LookupTemplateName(R, S, SS, QualType(), /*EnteringContext=*/false,
2062                        MemberOfUnknownSpecialization);
2063 
2064     if (MemberOfUnknownSpecialization ||
2065         (R.getResultKind() == LookupResult::NotFoundInCurrentInstantiation))
2066       return ActOnDependentIdExpression(SS, TemplateKWLoc, NameInfo,
2067                                         IsAddressOfOperand, TemplateArgs);
2068   } else {
2069     bool IvarLookupFollowUp = II && !SS.isSet() && getCurMethodDecl();
2070     LookupParsedName(R, S, &SS, !IvarLookupFollowUp);
2071 
2072     // If the result might be in a dependent base class, this is a dependent
2073     // id-expression.
2074     if (R.getResultKind() == LookupResult::NotFoundInCurrentInstantiation)
2075       return ActOnDependentIdExpression(SS, TemplateKWLoc, NameInfo,
2076                                         IsAddressOfOperand, TemplateArgs);
2077 
2078     // If this reference is in an Objective-C method, then we need to do
2079     // some special Objective-C lookup, too.
2080     if (IvarLookupFollowUp) {
2081       ExprResult E(LookupInObjCMethod(R, S, II, true));
2082       if (E.isInvalid())
2083         return ExprError();
2084 
2085       if (Expr *Ex = E.getAs<Expr>())
2086         return Ex;
2087     }
2088   }
2089 
2090   if (R.isAmbiguous())
2091     return ExprError();
2092 
2093   // This could be an implicitly declared function reference (legal in C90,
2094   // extension in C99, forbidden in C++).
2095   if (R.empty() && HasTrailingLParen && II && !getLangOpts().CPlusPlus) {
2096     NamedDecl *D = ImplicitlyDefineFunction(NameLoc, *II, S);
2097     if (D) R.addDecl(D);
2098   }
2099 
2100   // Determine whether this name might be a candidate for
2101   // argument-dependent lookup.
2102   bool ADL = UseArgumentDependentLookup(SS, R, HasTrailingLParen);
2103 
2104   if (R.empty() && !ADL) {
2105     if (SS.isEmpty() && getLangOpts().MSVCCompat) {
2106       if (Expr *E = recoverFromMSUnqualifiedLookup(*this, Context, NameInfo,
2107                                                    TemplateKWLoc, TemplateArgs))
2108         return E;
2109     }
2110 
2111     // Don't diagnose an empty lookup for inline assembly.
2112     if (IsInlineAsmIdentifier)
2113       return ExprError();
2114 
2115     // If this name wasn't predeclared and if this is not a function
2116     // call, diagnose the problem.
2117     TypoExpr *TE = nullptr;
2118     auto DefaultValidator = llvm::make_unique<CorrectionCandidateCallback>(
2119         II, SS.isValid() ? SS.getScopeRep() : nullptr);
2120     DefaultValidator->IsAddressOfOperand = IsAddressOfOperand;
2121     assert((!CCC || CCC->IsAddressOfOperand == IsAddressOfOperand) &&
2122            "Typo correction callback misconfigured");
2123     if (CCC) {
2124       // Make sure the callback knows what the typo being diagnosed is.
2125       CCC->setTypoName(II);
2126       if (SS.isValid())
2127         CCC->setTypoNNS(SS.getScopeRep());
2128     }
2129     if (DiagnoseEmptyLookup(S, SS, R,
2130                             CCC ? std::move(CCC) : std::move(DefaultValidator),
2131                             nullptr, None, &TE)) {
2132       if (TE && KeywordReplacement) {
2133         auto &State = getTypoExprState(TE);
2134         auto BestTC = State.Consumer->getNextCorrection();
2135         if (BestTC.isKeyword()) {
2136           auto *II = BestTC.getCorrectionAsIdentifierInfo();
2137           if (State.DiagHandler)
2138             State.DiagHandler(BestTC);
2139           KeywordReplacement->startToken();
2140           KeywordReplacement->setKind(II->getTokenID());
2141           KeywordReplacement->setIdentifierInfo(II);
2142           KeywordReplacement->setLocation(BestTC.getCorrectionRange().getBegin());
2143           // Clean up the state associated with the TypoExpr, since it has
2144           // now been diagnosed (without a call to CorrectDelayedTyposInExpr).
2145           clearDelayedTypo(TE);
2146           // Signal that a correction to a keyword was performed by returning a
2147           // valid-but-null ExprResult.
2148           return (Expr*)nullptr;
2149         }
2150         State.Consumer->resetCorrectionStream();
2151       }
2152       return TE ? TE : ExprError();
2153     }
2154 
2155     assert(!R.empty() &&
2156            "DiagnoseEmptyLookup returned false but added no results");
2157 
2158     // If we found an Objective-C instance variable, let
2159     // LookupInObjCMethod build the appropriate expression to
2160     // reference the ivar.
2161     if (ObjCIvarDecl *Ivar = R.getAsSingle<ObjCIvarDecl>()) {
2162       R.clear();
2163       ExprResult E(LookupInObjCMethod(R, S, Ivar->getIdentifier()));
2164       // In a hopelessly buggy code, Objective-C instance variable
2165       // lookup fails and no expression will be built to reference it.
2166       if (!E.isInvalid() && !E.get())
2167         return ExprError();
2168       return E;
2169     }
2170   }
2171 
2172   // This is guaranteed from this point on.
2173   assert(!R.empty() || ADL);
2174 
2175   // Check whether this might be a C++ implicit instance member access.
2176   // C++ [class.mfct.non-static]p3:
2177   //   When an id-expression that is not part of a class member access
2178   //   syntax and not used to form a pointer to member is used in the
2179   //   body of a non-static member function of class X, if name lookup
2180   //   resolves the name in the id-expression to a non-static non-type
2181   //   member of some class C, the id-expression is transformed into a
2182   //   class member access expression using (*this) as the
2183   //   postfix-expression to the left of the . operator.
2184   //
2185   // But we don't actually need to do this for '&' operands if R
2186   // resolved to a function or overloaded function set, because the
2187   // expression is ill-formed if it actually works out to be a
2188   // non-static member function:
2189   //
2190   // C++ [expr.ref]p4:
2191   //   Otherwise, if E1.E2 refers to a non-static member function. . .
2192   //   [t]he expression can be used only as the left-hand operand of a
2193   //   member function call.
2194   //
2195   // There are other safeguards against such uses, but it's important
2196   // to get this right here so that we don't end up making a
2197   // spuriously dependent expression if we're inside a dependent
2198   // instance method.
2199   if (!R.empty() && (*R.begin())->isCXXClassMember()) {
2200     bool MightBeImplicitMember;
2201     if (!IsAddressOfOperand)
2202       MightBeImplicitMember = true;
2203     else if (!SS.isEmpty())
2204       MightBeImplicitMember = false;
2205     else if (R.isOverloadedResult())
2206       MightBeImplicitMember = false;
2207     else if (R.isUnresolvableResult())
2208       MightBeImplicitMember = true;
2209     else
2210       MightBeImplicitMember = isa<FieldDecl>(R.getFoundDecl()) ||
2211                               isa<IndirectFieldDecl>(R.getFoundDecl()) ||
2212                               isa<MSPropertyDecl>(R.getFoundDecl());
2213 
2214     if (MightBeImplicitMember)
2215       return BuildPossibleImplicitMemberExpr(SS, TemplateKWLoc,
2216                                              R, TemplateArgs);
2217   }
2218 
2219   if (TemplateArgs || TemplateKWLoc.isValid()) {
2220 
2221     // In C++1y, if this is a variable template id, then check it
2222     // in BuildTemplateIdExpr().
2223     // The single lookup result must be a variable template declaration.
2224     if (Id.getKind() == UnqualifiedId::IK_TemplateId && Id.TemplateId &&
2225         Id.TemplateId->Kind == TNK_Var_template) {
2226       assert(R.getAsSingle<VarTemplateDecl>() &&
2227              "There should only be one declaration found.");
2228     }
2229 
2230     return BuildTemplateIdExpr(SS, TemplateKWLoc, R, ADL, TemplateArgs);
2231   }
2232 
2233   return BuildDeclarationNameExpr(SS, R, ADL);
2234 }
2235 
2236 /// BuildQualifiedDeclarationNameExpr - Build a C++ qualified
2237 /// declaration name, generally during template instantiation.
2238 /// There's a large number of things which don't need to be done along
2239 /// this path.
2240 ExprResult
BuildQualifiedDeclarationNameExpr(CXXScopeSpec & SS,const DeclarationNameInfo & NameInfo,bool IsAddressOfOperand,TypeSourceInfo ** RecoveryTSI)2241 Sema::BuildQualifiedDeclarationNameExpr(CXXScopeSpec &SS,
2242                                         const DeclarationNameInfo &NameInfo,
2243                                         bool IsAddressOfOperand,
2244                                         TypeSourceInfo **RecoveryTSI) {
2245   DeclContext *DC = computeDeclContext(SS, false);
2246   if (!DC)
2247     return BuildDependentDeclRefExpr(SS, /*TemplateKWLoc=*/SourceLocation(),
2248                                      NameInfo, /*TemplateArgs=*/nullptr);
2249 
2250   if (RequireCompleteDeclContext(SS, DC))
2251     return ExprError();
2252 
2253   LookupResult R(*this, NameInfo, LookupOrdinaryName);
2254   LookupQualifiedName(R, DC);
2255 
2256   if (R.isAmbiguous())
2257     return ExprError();
2258 
2259   if (R.getResultKind() == LookupResult::NotFoundInCurrentInstantiation)
2260     return BuildDependentDeclRefExpr(SS, /*TemplateKWLoc=*/SourceLocation(),
2261                                      NameInfo, /*TemplateArgs=*/nullptr);
2262 
2263   if (R.empty()) {
2264     Diag(NameInfo.getLoc(), diag::err_no_member)
2265       << NameInfo.getName() << DC << SS.getRange();
2266     return ExprError();
2267   }
2268 
2269   if (const TypeDecl *TD = R.getAsSingle<TypeDecl>()) {
2270     // Diagnose a missing typename if this resolved unambiguously to a type in
2271     // a dependent context.  If we can recover with a type, downgrade this to
2272     // a warning in Microsoft compatibility mode.
2273     unsigned DiagID = diag::err_typename_missing;
2274     if (RecoveryTSI && getLangOpts().MSVCCompat)
2275       DiagID = diag::ext_typename_missing;
2276     SourceLocation Loc = SS.getBeginLoc();
2277     auto D = Diag(Loc, DiagID);
2278     D << SS.getScopeRep() << NameInfo.getName().getAsString()
2279       << SourceRange(Loc, NameInfo.getEndLoc());
2280 
2281     // Don't recover if the caller isn't expecting us to or if we're in a SFINAE
2282     // context.
2283     if (!RecoveryTSI)
2284       return ExprError();
2285 
2286     // Only issue the fixit if we're prepared to recover.
2287     D << FixItHint::CreateInsertion(Loc, "typename ");
2288 
2289     // Recover by pretending this was an elaborated type.
2290     QualType Ty = Context.getTypeDeclType(TD);
2291     TypeLocBuilder TLB;
2292     TLB.pushTypeSpec(Ty).setNameLoc(NameInfo.getLoc());
2293 
2294     QualType ET = getElaboratedType(ETK_None, SS, Ty);
2295     ElaboratedTypeLoc QTL = TLB.push<ElaboratedTypeLoc>(ET);
2296     QTL.setElaboratedKeywordLoc(SourceLocation());
2297     QTL.setQualifierLoc(SS.getWithLocInContext(Context));
2298 
2299     *RecoveryTSI = TLB.getTypeSourceInfo(Context, ET);
2300 
2301     return ExprEmpty();
2302   }
2303 
2304   // Defend against this resolving to an implicit member access. We usually
2305   // won't get here if this might be a legitimate a class member (we end up in
2306   // BuildMemberReferenceExpr instead), but this can be valid if we're forming
2307   // a pointer-to-member or in an unevaluated context in C++11.
2308   if (!R.empty() && (*R.begin())->isCXXClassMember() && !IsAddressOfOperand)
2309     return BuildPossibleImplicitMemberExpr(SS,
2310                                            /*TemplateKWLoc=*/SourceLocation(),
2311                                            R, /*TemplateArgs=*/nullptr);
2312 
2313   return BuildDeclarationNameExpr(SS, R, /* ADL */ false);
2314 }
2315 
2316 /// LookupInObjCMethod - The parser has read a name in, and Sema has
2317 /// detected that we're currently inside an ObjC method.  Perform some
2318 /// additional lookup.
2319 ///
2320 /// Ideally, most of this would be done by lookup, but there's
2321 /// actually quite a lot of extra work involved.
2322 ///
2323 /// Returns a null sentinel to indicate trivial success.
2324 ExprResult
LookupInObjCMethod(LookupResult & Lookup,Scope * S,IdentifierInfo * II,bool AllowBuiltinCreation)2325 Sema::LookupInObjCMethod(LookupResult &Lookup, Scope *S,
2326                          IdentifierInfo *II, bool AllowBuiltinCreation) {
2327   SourceLocation Loc = Lookup.getNameLoc();
2328   ObjCMethodDecl *CurMethod = getCurMethodDecl();
2329 
2330   // Check for error condition which is already reported.
2331   if (!CurMethod)
2332     return ExprError();
2333 
2334   // There are two cases to handle here.  1) scoped lookup could have failed,
2335   // in which case we should look for an ivar.  2) scoped lookup could have
2336   // found a decl, but that decl is outside the current instance method (i.e.
2337   // a global variable).  In these two cases, we do a lookup for an ivar with
2338   // this name, if the lookup sucedes, we replace it our current decl.
2339 
2340   // If we're in a class method, we don't normally want to look for
2341   // ivars.  But if we don't find anything else, and there's an
2342   // ivar, that's an error.
2343   bool IsClassMethod = CurMethod->isClassMethod();
2344 
2345   bool LookForIvars;
2346   if (Lookup.empty())
2347     LookForIvars = true;
2348   else if (IsClassMethod)
2349     LookForIvars = false;
2350   else
2351     LookForIvars = (Lookup.isSingleResult() &&
2352                     Lookup.getFoundDecl()->isDefinedOutsideFunctionOrMethod());
2353   ObjCInterfaceDecl *IFace = nullptr;
2354   if (LookForIvars) {
2355     IFace = CurMethod->getClassInterface();
2356     ObjCInterfaceDecl *ClassDeclared;
2357     ObjCIvarDecl *IV = nullptr;
2358     if (IFace && (IV = IFace->lookupInstanceVariable(II, ClassDeclared))) {
2359       // Diagnose using an ivar in a class method.
2360       if (IsClassMethod)
2361         return ExprError(Diag(Loc, diag::error_ivar_use_in_class_method)
2362                          << IV->getDeclName());
2363 
2364       // If we're referencing an invalid decl, just return this as a silent
2365       // error node.  The error diagnostic was already emitted on the decl.
2366       if (IV->isInvalidDecl())
2367         return ExprError();
2368 
2369       // Check if referencing a field with __attribute__((deprecated)).
2370       if (DiagnoseUseOfDecl(IV, Loc))
2371         return ExprError();
2372 
2373       // Diagnose the use of an ivar outside of the declaring class.
2374       if (IV->getAccessControl() == ObjCIvarDecl::Private &&
2375           !declaresSameEntity(ClassDeclared, IFace) &&
2376           !getLangOpts().DebuggerSupport)
2377         Diag(Loc, diag::error_private_ivar_access) << IV->getDeclName();
2378 
2379       // FIXME: This should use a new expr for a direct reference, don't
2380       // turn this into Self->ivar, just return a BareIVarExpr or something.
2381       IdentifierInfo &II = Context.Idents.get("self");
2382       UnqualifiedId SelfName;
2383       SelfName.setIdentifier(&II, SourceLocation());
2384       SelfName.setKind(UnqualifiedId::IK_ImplicitSelfParam);
2385       CXXScopeSpec SelfScopeSpec;
2386       SourceLocation TemplateKWLoc;
2387       ExprResult SelfExpr = ActOnIdExpression(S, SelfScopeSpec, TemplateKWLoc,
2388                                               SelfName, false, false);
2389       if (SelfExpr.isInvalid())
2390         return ExprError();
2391 
2392       SelfExpr = DefaultLvalueConversion(SelfExpr.get());
2393       if (SelfExpr.isInvalid())
2394         return ExprError();
2395 
2396       MarkAnyDeclReferenced(Loc, IV, true);
2397 
2398       ObjCMethodFamily MF = CurMethod->getMethodFamily();
2399       if (MF != OMF_init && MF != OMF_dealloc && MF != OMF_finalize &&
2400           !IvarBacksCurrentMethodAccessor(IFace, CurMethod, IV))
2401         Diag(Loc, diag::warn_direct_ivar_access) << IV->getDeclName();
2402 
2403       ObjCIvarRefExpr *Result = new (Context)
2404           ObjCIvarRefExpr(IV, IV->getType(), Loc, IV->getLocation(),
2405                           SelfExpr.get(), true, true);
2406 
2407       if (getLangOpts().ObjCAutoRefCount) {
2408         if (IV->getType().getObjCLifetime() == Qualifiers::OCL_Weak) {
2409           if (!Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, Loc))
2410             recordUseOfEvaluatedWeak(Result);
2411         }
2412         if (CurContext->isClosure())
2413           Diag(Loc, diag::warn_implicitly_retains_self)
2414             << FixItHint::CreateInsertion(Loc, "self->");
2415       }
2416 
2417       return Result;
2418     }
2419   } else if (CurMethod->isInstanceMethod()) {
2420     // We should warn if a local variable hides an ivar.
2421     if (ObjCInterfaceDecl *IFace = CurMethod->getClassInterface()) {
2422       ObjCInterfaceDecl *ClassDeclared;
2423       if (ObjCIvarDecl *IV = IFace->lookupInstanceVariable(II, ClassDeclared)) {
2424         if (IV->getAccessControl() != ObjCIvarDecl::Private ||
2425             declaresSameEntity(IFace, ClassDeclared))
2426           Diag(Loc, diag::warn_ivar_use_hidden) << IV->getDeclName();
2427       }
2428     }
2429   } else if (Lookup.isSingleResult() &&
2430              Lookup.getFoundDecl()->isDefinedOutsideFunctionOrMethod()) {
2431     // If accessing a stand-alone ivar in a class method, this is an error.
2432     if (const ObjCIvarDecl *IV = dyn_cast<ObjCIvarDecl>(Lookup.getFoundDecl()))
2433       return ExprError(Diag(Loc, diag::error_ivar_use_in_class_method)
2434                        << IV->getDeclName());
2435   }
2436 
2437   if (Lookup.empty() && II && AllowBuiltinCreation) {
2438     // FIXME. Consolidate this with similar code in LookupName.
2439     if (unsigned BuiltinID = II->getBuiltinID()) {
2440       if (!(getLangOpts().CPlusPlus &&
2441             Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID))) {
2442         NamedDecl *D = LazilyCreateBuiltin((IdentifierInfo *)II, BuiltinID,
2443                                            S, Lookup.isForRedeclaration(),
2444                                            Lookup.getNameLoc());
2445         if (D) Lookup.addDecl(D);
2446       }
2447     }
2448   }
2449   // Sentinel value saying that we didn't do anything special.
2450   return ExprResult((Expr *)nullptr);
2451 }
2452 
2453 /// \brief Cast a base object to a member's actual type.
2454 ///
2455 /// Logically this happens in three phases:
2456 ///
2457 /// * First we cast from the base type to the naming class.
2458 ///   The naming class is the class into which we were looking
2459 ///   when we found the member;  it's the qualifier type if a
2460 ///   qualifier was provided, and otherwise it's the base type.
2461 ///
2462 /// * Next we cast from the naming class to the declaring class.
2463 ///   If the member we found was brought into a class's scope by
2464 ///   a using declaration, this is that class;  otherwise it's
2465 ///   the class declaring the member.
2466 ///
2467 /// * Finally we cast from the declaring class to the "true"
2468 ///   declaring class of the member.  This conversion does not
2469 ///   obey access control.
2470 ExprResult
PerformObjectMemberConversion(Expr * From,NestedNameSpecifier * Qualifier,NamedDecl * FoundDecl,NamedDecl * Member)2471 Sema::PerformObjectMemberConversion(Expr *From,
2472                                     NestedNameSpecifier *Qualifier,
2473                                     NamedDecl *FoundDecl,
2474                                     NamedDecl *Member) {
2475   CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Member->getDeclContext());
2476   if (!RD)
2477     return From;
2478 
2479   QualType DestRecordType;
2480   QualType DestType;
2481   QualType FromRecordType;
2482   QualType FromType = From->getType();
2483   bool PointerConversions = false;
2484   if (isa<FieldDecl>(Member)) {
2485     DestRecordType = Context.getCanonicalType(Context.getTypeDeclType(RD));
2486 
2487     if (FromType->getAs<PointerType>()) {
2488       DestType = Context.getPointerType(DestRecordType);
2489       FromRecordType = FromType->getPointeeType();
2490       PointerConversions = true;
2491     } else {
2492       DestType = DestRecordType;
2493       FromRecordType = FromType;
2494     }
2495   } else if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Member)) {
2496     if (Method->isStatic())
2497       return From;
2498 
2499     DestType = Method->getThisType(Context);
2500     DestRecordType = DestType->getPointeeType();
2501 
2502     if (FromType->getAs<PointerType>()) {
2503       FromRecordType = FromType->getPointeeType();
2504       PointerConversions = true;
2505     } else {
2506       FromRecordType = FromType;
2507       DestType = DestRecordType;
2508     }
2509   } else {
2510     // No conversion necessary.
2511     return From;
2512   }
2513 
2514   if (DestType->isDependentType() || FromType->isDependentType())
2515     return From;
2516 
2517   // If the unqualified types are the same, no conversion is necessary.
2518   if (Context.hasSameUnqualifiedType(FromRecordType, DestRecordType))
2519     return From;
2520 
2521   SourceRange FromRange = From->getSourceRange();
2522   SourceLocation FromLoc = FromRange.getBegin();
2523 
2524   ExprValueKind VK = From->getValueKind();
2525 
2526   // C++ [class.member.lookup]p8:
2527   //   [...] Ambiguities can often be resolved by qualifying a name with its
2528   //   class name.
2529   //
2530   // If the member was a qualified name and the qualified referred to a
2531   // specific base subobject type, we'll cast to that intermediate type
2532   // first and then to the object in which the member is declared. That allows
2533   // one to resolve ambiguities in, e.g., a diamond-shaped hierarchy such as:
2534   //
2535   //   class Base { public: int x; };
2536   //   class Derived1 : public Base { };
2537   //   class Derived2 : public Base { };
2538   //   class VeryDerived : public Derived1, public Derived2 { void f(); };
2539   //
2540   //   void VeryDerived::f() {
2541   //     x = 17; // error: ambiguous base subobjects
2542   //     Derived1::x = 17; // okay, pick the Base subobject of Derived1
2543   //   }
2544   if (Qualifier && Qualifier->getAsType()) {
2545     QualType QType = QualType(Qualifier->getAsType(), 0);
2546     assert(QType->isRecordType() && "lookup done with non-record type");
2547 
2548     QualType QRecordType = QualType(QType->getAs<RecordType>(), 0);
2549 
2550     // In C++98, the qualifier type doesn't actually have to be a base
2551     // type of the object type, in which case we just ignore it.
2552     // Otherwise build the appropriate casts.
2553     if (IsDerivedFrom(FromRecordType, QRecordType)) {
2554       CXXCastPath BasePath;
2555       if (CheckDerivedToBaseConversion(FromRecordType, QRecordType,
2556                                        FromLoc, FromRange, &BasePath))
2557         return ExprError();
2558 
2559       if (PointerConversions)
2560         QType = Context.getPointerType(QType);
2561       From = ImpCastExprToType(From, QType, CK_UncheckedDerivedToBase,
2562                                VK, &BasePath).get();
2563 
2564       FromType = QType;
2565       FromRecordType = QRecordType;
2566 
2567       // If the qualifier type was the same as the destination type,
2568       // we're done.
2569       if (Context.hasSameUnqualifiedType(FromRecordType, DestRecordType))
2570         return From;
2571     }
2572   }
2573 
2574   bool IgnoreAccess = false;
2575 
2576   // If we actually found the member through a using declaration, cast
2577   // down to the using declaration's type.
2578   //
2579   // Pointer equality is fine here because only one declaration of a
2580   // class ever has member declarations.
2581   if (FoundDecl->getDeclContext() != Member->getDeclContext()) {
2582     assert(isa<UsingShadowDecl>(FoundDecl));
2583     QualType URecordType = Context.getTypeDeclType(
2584                            cast<CXXRecordDecl>(FoundDecl->getDeclContext()));
2585 
2586     // We only need to do this if the naming-class to declaring-class
2587     // conversion is non-trivial.
2588     if (!Context.hasSameUnqualifiedType(FromRecordType, URecordType)) {
2589       assert(IsDerivedFrom(FromRecordType, URecordType));
2590       CXXCastPath BasePath;
2591       if (CheckDerivedToBaseConversion(FromRecordType, URecordType,
2592                                        FromLoc, FromRange, &BasePath))
2593         return ExprError();
2594 
2595       QualType UType = URecordType;
2596       if (PointerConversions)
2597         UType = Context.getPointerType(UType);
2598       From = ImpCastExprToType(From, UType, CK_UncheckedDerivedToBase,
2599                                VK, &BasePath).get();
2600       FromType = UType;
2601       FromRecordType = URecordType;
2602     }
2603 
2604     // We don't do access control for the conversion from the
2605     // declaring class to the true declaring class.
2606     IgnoreAccess = true;
2607   }
2608 
2609   CXXCastPath BasePath;
2610   if (CheckDerivedToBaseConversion(FromRecordType, DestRecordType,
2611                                    FromLoc, FromRange, &BasePath,
2612                                    IgnoreAccess))
2613     return ExprError();
2614 
2615   return ImpCastExprToType(From, DestType, CK_UncheckedDerivedToBase,
2616                            VK, &BasePath);
2617 }
2618 
UseArgumentDependentLookup(const CXXScopeSpec & SS,const LookupResult & R,bool HasTrailingLParen)2619 bool Sema::UseArgumentDependentLookup(const CXXScopeSpec &SS,
2620                                       const LookupResult &R,
2621                                       bool HasTrailingLParen) {
2622   // Only when used directly as the postfix-expression of a call.
2623   if (!HasTrailingLParen)
2624     return false;
2625 
2626   // Never if a scope specifier was provided.
2627   if (SS.isSet())
2628     return false;
2629 
2630   // Only in C++ or ObjC++.
2631   if (!getLangOpts().CPlusPlus)
2632     return false;
2633 
2634   // Turn off ADL when we find certain kinds of declarations during
2635   // normal lookup:
2636   for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) {
2637     NamedDecl *D = *I;
2638 
2639     // C++0x [basic.lookup.argdep]p3:
2640     //     -- a declaration of a class member
2641     // Since using decls preserve this property, we check this on the
2642     // original decl.
2643     if (D->isCXXClassMember())
2644       return false;
2645 
2646     // C++0x [basic.lookup.argdep]p3:
2647     //     -- a block-scope function declaration that is not a
2648     //        using-declaration
2649     // NOTE: we also trigger this for function templates (in fact, we
2650     // don't check the decl type at all, since all other decl types
2651     // turn off ADL anyway).
2652     if (isa<UsingShadowDecl>(D))
2653       D = cast<UsingShadowDecl>(D)->getTargetDecl();
2654     else if (D->getLexicalDeclContext()->isFunctionOrMethod())
2655       return false;
2656 
2657     // C++0x [basic.lookup.argdep]p3:
2658     //     -- a declaration that is neither a function or a function
2659     //        template
2660     // And also for builtin functions.
2661     if (isa<FunctionDecl>(D)) {
2662       FunctionDecl *FDecl = cast<FunctionDecl>(D);
2663 
2664       // But also builtin functions.
2665       if (FDecl->getBuiltinID() && FDecl->isImplicit())
2666         return false;
2667     } else if (!isa<FunctionTemplateDecl>(D))
2668       return false;
2669   }
2670 
2671   return true;
2672 }
2673 
2674 
2675 /// Diagnoses obvious problems with the use of the given declaration
2676 /// as an expression.  This is only actually called for lookups that
2677 /// were not overloaded, and it doesn't promise that the declaration
2678 /// will in fact be used.
CheckDeclInExpr(Sema & S,SourceLocation Loc,NamedDecl * D)2679 static bool CheckDeclInExpr(Sema &S, SourceLocation Loc, NamedDecl *D) {
2680   if (isa<TypedefNameDecl>(D)) {
2681     S.Diag(Loc, diag::err_unexpected_typedef) << D->getDeclName();
2682     return true;
2683   }
2684 
2685   if (isa<ObjCInterfaceDecl>(D)) {
2686     S.Diag(Loc, diag::err_unexpected_interface) << D->getDeclName();
2687     return true;
2688   }
2689 
2690   if (isa<NamespaceDecl>(D)) {
2691     S.Diag(Loc, diag::err_unexpected_namespace) << D->getDeclName();
2692     return true;
2693   }
2694 
2695   return false;
2696 }
2697 
BuildDeclarationNameExpr(const CXXScopeSpec & SS,LookupResult & R,bool NeedsADL,bool AcceptInvalidDecl)2698 ExprResult Sema::BuildDeclarationNameExpr(const CXXScopeSpec &SS,
2699                                           LookupResult &R, bool NeedsADL,
2700                                           bool AcceptInvalidDecl) {
2701   // If this is a single, fully-resolved result and we don't need ADL,
2702   // just build an ordinary singleton decl ref.
2703   if (!NeedsADL && R.isSingleResult() && !R.getAsSingle<FunctionTemplateDecl>())
2704     return BuildDeclarationNameExpr(SS, R.getLookupNameInfo(), R.getFoundDecl(),
2705                                     R.getRepresentativeDecl(), nullptr,
2706                                     AcceptInvalidDecl);
2707 
2708   // We only need to check the declaration if there's exactly one
2709   // result, because in the overloaded case the results can only be
2710   // functions and function templates.
2711   if (R.isSingleResult() &&
2712       CheckDeclInExpr(*this, R.getNameLoc(), R.getFoundDecl()))
2713     return ExprError();
2714 
2715   // Otherwise, just build an unresolved lookup expression.  Suppress
2716   // any lookup-related diagnostics; we'll hash these out later, when
2717   // we've picked a target.
2718   R.suppressDiagnostics();
2719 
2720   UnresolvedLookupExpr *ULE
2721     = UnresolvedLookupExpr::Create(Context, R.getNamingClass(),
2722                                    SS.getWithLocInContext(Context),
2723                                    R.getLookupNameInfo(),
2724                                    NeedsADL, R.isOverloadedResult(),
2725                                    R.begin(), R.end());
2726 
2727   return ULE;
2728 }
2729 
2730 /// \brief Complete semantic analysis for a reference to the given declaration.
BuildDeclarationNameExpr(const CXXScopeSpec & SS,const DeclarationNameInfo & NameInfo,NamedDecl * D,NamedDecl * FoundD,const TemplateArgumentListInfo * TemplateArgs,bool AcceptInvalidDecl)2731 ExprResult Sema::BuildDeclarationNameExpr(
2732     const CXXScopeSpec &SS, const DeclarationNameInfo &NameInfo, NamedDecl *D,
2733     NamedDecl *FoundD, const TemplateArgumentListInfo *TemplateArgs,
2734     bool AcceptInvalidDecl) {
2735   assert(D && "Cannot refer to a NULL declaration");
2736   assert(!isa<FunctionTemplateDecl>(D) &&
2737          "Cannot refer unambiguously to a function template");
2738 
2739   SourceLocation Loc = NameInfo.getLoc();
2740   if (CheckDeclInExpr(*this, Loc, D))
2741     return ExprError();
2742 
2743   if (TemplateDecl *Template = dyn_cast<TemplateDecl>(D)) {
2744     // Specifically diagnose references to class templates that are missing
2745     // a template argument list.
2746     Diag(Loc, diag::err_template_decl_ref) << (isa<VarTemplateDecl>(D) ? 1 : 0)
2747                                            << Template << SS.getRange();
2748     Diag(Template->getLocation(), diag::note_template_decl_here);
2749     return ExprError();
2750   }
2751 
2752   // Make sure that we're referring to a value.
2753   ValueDecl *VD = dyn_cast<ValueDecl>(D);
2754   if (!VD) {
2755     Diag(Loc, diag::err_ref_non_value)
2756       << D << SS.getRange();
2757     Diag(D->getLocation(), diag::note_declared_at);
2758     return ExprError();
2759   }
2760 
2761   // Check whether this declaration can be used. Note that we suppress
2762   // this check when we're going to perform argument-dependent lookup
2763   // on this function name, because this might not be the function
2764   // that overload resolution actually selects.
2765   if (DiagnoseUseOfDecl(VD, Loc))
2766     return ExprError();
2767 
2768   // Only create DeclRefExpr's for valid Decl's.
2769   if (VD->isInvalidDecl() && !AcceptInvalidDecl)
2770     return ExprError();
2771 
2772   // Handle members of anonymous structs and unions.  If we got here,
2773   // and the reference is to a class member indirect field, then this
2774   // must be the subject of a pointer-to-member expression.
2775   if (IndirectFieldDecl *indirectField = dyn_cast<IndirectFieldDecl>(VD))
2776     if (!indirectField->isCXXClassMember())
2777       return BuildAnonymousStructUnionMemberReference(SS, NameInfo.getLoc(),
2778                                                       indirectField);
2779 
2780   {
2781     QualType type = VD->getType();
2782     ExprValueKind valueKind = VK_RValue;
2783 
2784     switch (D->getKind()) {
2785     // Ignore all the non-ValueDecl kinds.
2786 #define ABSTRACT_DECL(kind)
2787 #define VALUE(type, base)
2788 #define DECL(type, base) \
2789     case Decl::type:
2790 #include "clang/AST/DeclNodes.inc"
2791       llvm_unreachable("invalid value decl kind");
2792 
2793     // These shouldn't make it here.
2794     case Decl::ObjCAtDefsField:
2795     case Decl::ObjCIvar:
2796       llvm_unreachable("forming non-member reference to ivar?");
2797 
2798     // Enum constants are always r-values and never references.
2799     // Unresolved using declarations are dependent.
2800     case Decl::EnumConstant:
2801     case Decl::UnresolvedUsingValue:
2802       valueKind = VK_RValue;
2803       break;
2804 
2805     // Fields and indirect fields that got here must be for
2806     // pointer-to-member expressions; we just call them l-values for
2807     // internal consistency, because this subexpression doesn't really
2808     // exist in the high-level semantics.
2809     case Decl::Field:
2810     case Decl::IndirectField:
2811       assert(getLangOpts().CPlusPlus &&
2812              "building reference to field in C?");
2813 
2814       // These can't have reference type in well-formed programs, but
2815       // for internal consistency we do this anyway.
2816       type = type.getNonReferenceType();
2817       valueKind = VK_LValue;
2818       break;
2819 
2820     // Non-type template parameters are either l-values or r-values
2821     // depending on the type.
2822     case Decl::NonTypeTemplateParm: {
2823       if (const ReferenceType *reftype = type->getAs<ReferenceType>()) {
2824         type = reftype->getPointeeType();
2825         valueKind = VK_LValue; // even if the parameter is an r-value reference
2826         break;
2827       }
2828 
2829       // For non-references, we need to strip qualifiers just in case
2830       // the template parameter was declared as 'const int' or whatever.
2831       valueKind = VK_RValue;
2832       type = type.getUnqualifiedType();
2833       break;
2834     }
2835 
2836     case Decl::Var:
2837     case Decl::VarTemplateSpecialization:
2838     case Decl::VarTemplatePartialSpecialization:
2839       // In C, "extern void blah;" is valid and is an r-value.
2840       if (!getLangOpts().CPlusPlus &&
2841           !type.hasQualifiers() &&
2842           type->isVoidType()) {
2843         valueKind = VK_RValue;
2844         break;
2845       }
2846       // fallthrough
2847 
2848     case Decl::ImplicitParam:
2849     case Decl::ParmVar: {
2850       // These are always l-values.
2851       valueKind = VK_LValue;
2852       type = type.getNonReferenceType();
2853 
2854       // FIXME: Does the addition of const really only apply in
2855       // potentially-evaluated contexts? Since the variable isn't actually
2856       // captured in an unevaluated context, it seems that the answer is no.
2857       if (!isUnevaluatedContext()) {
2858         QualType CapturedType = getCapturedDeclRefType(cast<VarDecl>(VD), Loc);
2859         if (!CapturedType.isNull())
2860           type = CapturedType;
2861       }
2862 
2863       break;
2864     }
2865 
2866     case Decl::Function: {
2867       if (unsigned BID = cast<FunctionDecl>(VD)->getBuiltinID()) {
2868         if (!Context.BuiltinInfo.isPredefinedLibFunction(BID)) {
2869           type = Context.BuiltinFnTy;
2870           valueKind = VK_RValue;
2871           break;
2872         }
2873       }
2874 
2875       const FunctionType *fty = type->castAs<FunctionType>();
2876 
2877       // If we're referring to a function with an __unknown_anytype
2878       // result type, make the entire expression __unknown_anytype.
2879       if (fty->getReturnType() == Context.UnknownAnyTy) {
2880         type = Context.UnknownAnyTy;
2881         valueKind = VK_RValue;
2882         break;
2883       }
2884 
2885       // Functions are l-values in C++.
2886       if (getLangOpts().CPlusPlus) {
2887         valueKind = VK_LValue;
2888         break;
2889       }
2890 
2891       // C99 DR 316 says that, if a function type comes from a
2892       // function definition (without a prototype), that type is only
2893       // used for checking compatibility. Therefore, when referencing
2894       // the function, we pretend that we don't have the full function
2895       // type.
2896       if (!cast<FunctionDecl>(VD)->hasPrototype() &&
2897           isa<FunctionProtoType>(fty))
2898         type = Context.getFunctionNoProtoType(fty->getReturnType(),
2899                                               fty->getExtInfo());
2900 
2901       // Functions are r-values in C.
2902       valueKind = VK_RValue;
2903       break;
2904     }
2905 
2906     case Decl::MSProperty:
2907       valueKind = VK_LValue;
2908       break;
2909 
2910     case Decl::CXXMethod:
2911       // If we're referring to a method with an __unknown_anytype
2912       // result type, make the entire expression __unknown_anytype.
2913       // This should only be possible with a type written directly.
2914       if (const FunctionProtoType *proto
2915             = dyn_cast<FunctionProtoType>(VD->getType()))
2916         if (proto->getReturnType() == Context.UnknownAnyTy) {
2917           type = Context.UnknownAnyTy;
2918           valueKind = VK_RValue;
2919           break;
2920         }
2921 
2922       // C++ methods are l-values if static, r-values if non-static.
2923       if (cast<CXXMethodDecl>(VD)->isStatic()) {
2924         valueKind = VK_LValue;
2925         break;
2926       }
2927       // fallthrough
2928 
2929     case Decl::CXXConversion:
2930     case Decl::CXXDestructor:
2931     case Decl::CXXConstructor:
2932       valueKind = VK_RValue;
2933       break;
2934     }
2935 
2936     return BuildDeclRefExpr(VD, type, valueKind, NameInfo, &SS, FoundD,
2937                             TemplateArgs);
2938   }
2939 }
2940 
ConvertUTF8ToWideString(unsigned CharByteWidth,StringRef Source,SmallString<32> & Target)2941 static void ConvertUTF8ToWideString(unsigned CharByteWidth, StringRef Source,
2942                                     SmallString<32> &Target) {
2943   Target.resize(CharByteWidth * (Source.size() + 1));
2944   char *ResultPtr = &Target[0];
2945   const UTF8 *ErrorPtr;
2946   bool success = ConvertUTF8toWide(CharByteWidth, Source, ResultPtr, ErrorPtr);
2947   (void)success;
2948   assert(success);
2949   Target.resize(ResultPtr - &Target[0]);
2950 }
2951 
BuildPredefinedExpr(SourceLocation Loc,PredefinedExpr::IdentType IT)2952 ExprResult Sema::BuildPredefinedExpr(SourceLocation Loc,
2953                                      PredefinedExpr::IdentType IT) {
2954   // Pick the current block, lambda, captured statement or function.
2955   Decl *currentDecl = nullptr;
2956   if (const BlockScopeInfo *BSI = getCurBlock())
2957     currentDecl = BSI->TheDecl;
2958   else if (const LambdaScopeInfo *LSI = getCurLambda())
2959     currentDecl = LSI->CallOperator;
2960   else if (const CapturedRegionScopeInfo *CSI = getCurCapturedRegion())
2961     currentDecl = CSI->TheCapturedDecl;
2962   else
2963     currentDecl = getCurFunctionOrMethodDecl();
2964 
2965   if (!currentDecl) {
2966     Diag(Loc, diag::ext_predef_outside_function);
2967     currentDecl = Context.getTranslationUnitDecl();
2968   }
2969 
2970   QualType ResTy;
2971   StringLiteral *SL = nullptr;
2972   if (cast<DeclContext>(currentDecl)->isDependentContext())
2973     ResTy = Context.DependentTy;
2974   else {
2975     // Pre-defined identifiers are of type char[x], where x is the length of
2976     // the string.
2977     auto Str = PredefinedExpr::ComputeName(IT, currentDecl);
2978     unsigned Length = Str.length();
2979 
2980     llvm::APInt LengthI(32, Length + 1);
2981     if (IT == PredefinedExpr::LFunction) {
2982       ResTy = Context.WideCharTy.withConst();
2983       SmallString<32> RawChars;
2984       ConvertUTF8ToWideString(Context.getTypeSizeInChars(ResTy).getQuantity(),
2985                               Str, RawChars);
2986       ResTy = Context.getConstantArrayType(ResTy, LengthI, ArrayType::Normal,
2987                                            /*IndexTypeQuals*/ 0);
2988       SL = StringLiteral::Create(Context, RawChars, StringLiteral::Wide,
2989                                  /*Pascal*/ false, ResTy, Loc);
2990     } else {
2991       ResTy = Context.CharTy.withConst();
2992       ResTy = Context.getConstantArrayType(ResTy, LengthI, ArrayType::Normal,
2993                                            /*IndexTypeQuals*/ 0);
2994       SL = StringLiteral::Create(Context, Str, StringLiteral::Ascii,
2995                                  /*Pascal*/ false, ResTy, Loc);
2996     }
2997   }
2998 
2999   return new (Context) PredefinedExpr(Loc, ResTy, IT, SL);
3000 }
3001 
ActOnPredefinedExpr(SourceLocation Loc,tok::TokenKind Kind)3002 ExprResult Sema::ActOnPredefinedExpr(SourceLocation Loc, tok::TokenKind Kind) {
3003   PredefinedExpr::IdentType IT;
3004 
3005   switch (Kind) {
3006   default: llvm_unreachable("Unknown simple primary expr!");
3007   case tok::kw___func__: IT = PredefinedExpr::Func; break; // [C99 6.4.2.2]
3008   case tok::kw___FUNCTION__: IT = PredefinedExpr::Function; break;
3009   case tok::kw___FUNCDNAME__: IT = PredefinedExpr::FuncDName; break; // [MS]
3010   case tok::kw___FUNCSIG__: IT = PredefinedExpr::FuncSig; break; // [MS]
3011   case tok::kw_L__FUNCTION__: IT = PredefinedExpr::LFunction; break;
3012   case tok::kw___PRETTY_FUNCTION__: IT = PredefinedExpr::PrettyFunction; break;
3013   }
3014 
3015   return BuildPredefinedExpr(Loc, IT);
3016 }
3017 
ActOnCharacterConstant(const Token & Tok,Scope * UDLScope)3018 ExprResult Sema::ActOnCharacterConstant(const Token &Tok, Scope *UDLScope) {
3019   SmallString<16> CharBuffer;
3020   bool Invalid = false;
3021   StringRef ThisTok = PP.getSpelling(Tok, CharBuffer, &Invalid);
3022   if (Invalid)
3023     return ExprError();
3024 
3025   CharLiteralParser Literal(ThisTok.begin(), ThisTok.end(), Tok.getLocation(),
3026                             PP, Tok.getKind());
3027   if (Literal.hadError())
3028     return ExprError();
3029 
3030   QualType Ty;
3031   if (Literal.isWide())
3032     Ty = Context.WideCharTy; // L'x' -> wchar_t in C and C++.
3033   else if (Literal.isUTF16())
3034     Ty = Context.Char16Ty; // u'x' -> char16_t in C11 and C++11.
3035   else if (Literal.isUTF32())
3036     Ty = Context.Char32Ty; // U'x' -> char32_t in C11 and C++11.
3037   else if (!getLangOpts().CPlusPlus || Literal.isMultiChar())
3038     Ty = Context.IntTy;   // 'x' -> int in C, 'wxyz' -> int in C++.
3039   else
3040     Ty = Context.CharTy;  // 'x' -> char in C++
3041 
3042   CharacterLiteral::CharacterKind Kind = CharacterLiteral::Ascii;
3043   if (Literal.isWide())
3044     Kind = CharacterLiteral::Wide;
3045   else if (Literal.isUTF16())
3046     Kind = CharacterLiteral::UTF16;
3047   else if (Literal.isUTF32())
3048     Kind = CharacterLiteral::UTF32;
3049 
3050   Expr *Lit = new (Context) CharacterLiteral(Literal.getValue(), Kind, Ty,
3051                                              Tok.getLocation());
3052 
3053   if (Literal.getUDSuffix().empty())
3054     return Lit;
3055 
3056   // We're building a user-defined literal.
3057   IdentifierInfo *UDSuffix = &Context.Idents.get(Literal.getUDSuffix());
3058   SourceLocation UDSuffixLoc =
3059     getUDSuffixLoc(*this, Tok.getLocation(), Literal.getUDSuffixOffset());
3060 
3061   // Make sure we're allowed user-defined literals here.
3062   if (!UDLScope)
3063     return ExprError(Diag(UDSuffixLoc, diag::err_invalid_character_udl));
3064 
3065   // C++11 [lex.ext]p6: The literal L is treated as a call of the form
3066   //   operator "" X (ch)
3067   return BuildCookedLiteralOperatorCall(*this, UDLScope, UDSuffix, UDSuffixLoc,
3068                                         Lit, Tok.getLocation());
3069 }
3070 
ActOnIntegerConstant(SourceLocation Loc,uint64_t Val)3071 ExprResult Sema::ActOnIntegerConstant(SourceLocation Loc, uint64_t Val) {
3072   unsigned IntSize = Context.getTargetInfo().getIntWidth();
3073   return IntegerLiteral::Create(Context, llvm::APInt(IntSize, Val),
3074                                 Context.IntTy, Loc);
3075 }
3076 
BuildFloatingLiteral(Sema & S,NumericLiteralParser & Literal,QualType Ty,SourceLocation Loc)3077 static Expr *BuildFloatingLiteral(Sema &S, NumericLiteralParser &Literal,
3078                                   QualType Ty, SourceLocation Loc) {
3079   const llvm::fltSemantics &Format = S.Context.getFloatTypeSemantics(Ty);
3080 
3081   using llvm::APFloat;
3082   APFloat Val(Format);
3083 
3084   APFloat::opStatus result = Literal.GetFloatValue(Val);
3085 
3086   // Overflow is always an error, but underflow is only an error if
3087   // we underflowed to zero (APFloat reports denormals as underflow).
3088   if ((result & APFloat::opOverflow) ||
3089       ((result & APFloat::opUnderflow) && Val.isZero())) {
3090     unsigned diagnostic;
3091     SmallString<20> buffer;
3092     if (result & APFloat::opOverflow) {
3093       diagnostic = diag::warn_float_overflow;
3094       APFloat::getLargest(Format).toString(buffer);
3095     } else {
3096       diagnostic = diag::warn_float_underflow;
3097       APFloat::getSmallest(Format).toString(buffer);
3098     }
3099 
3100     S.Diag(Loc, diagnostic)
3101       << Ty
3102       << StringRef(buffer.data(), buffer.size());
3103   }
3104 
3105   bool isExact = (result == APFloat::opOK);
3106   return FloatingLiteral::Create(S.Context, Val, isExact, Ty, Loc);
3107 }
3108 
CheckLoopHintExpr(Expr * E,SourceLocation Loc)3109 bool Sema::CheckLoopHintExpr(Expr *E, SourceLocation Loc) {
3110   assert(E && "Invalid expression");
3111 
3112   if (E->isValueDependent())
3113     return false;
3114 
3115   QualType QT = E->getType();
3116   if (!QT->isIntegerType() || QT->isBooleanType() || QT->isCharType()) {
3117     Diag(E->getExprLoc(), diag::err_pragma_loop_invalid_argument_type) << QT;
3118     return true;
3119   }
3120 
3121   llvm::APSInt ValueAPS;
3122   ExprResult R = VerifyIntegerConstantExpression(E, &ValueAPS);
3123 
3124   if (R.isInvalid())
3125     return true;
3126 
3127   bool ValueIsPositive = ValueAPS.isStrictlyPositive();
3128   if (!ValueIsPositive || ValueAPS.getActiveBits() > 31) {
3129     Diag(E->getExprLoc(), diag::err_pragma_loop_invalid_argument_value)
3130         << ValueAPS.toString(10) << ValueIsPositive;
3131     return true;
3132   }
3133 
3134   return false;
3135 }
3136 
ActOnNumericConstant(const Token & Tok,Scope * UDLScope)3137 ExprResult Sema::ActOnNumericConstant(const Token &Tok, Scope *UDLScope) {
3138   // Fast path for a single digit (which is quite common).  A single digit
3139   // cannot have a trigraph, escaped newline, radix prefix, or suffix.
3140   if (Tok.getLength() == 1) {
3141     const char Val = PP.getSpellingOfSingleCharacterNumericConstant(Tok);
3142     return ActOnIntegerConstant(Tok.getLocation(), Val-'0');
3143   }
3144 
3145   SmallString<128> SpellingBuffer;
3146   // NumericLiteralParser wants to overread by one character.  Add padding to
3147   // the buffer in case the token is copied to the buffer.  If getSpelling()
3148   // returns a StringRef to the memory buffer, it should have a null char at
3149   // the EOF, so it is also safe.
3150   SpellingBuffer.resize(Tok.getLength() + 1);
3151 
3152   // Get the spelling of the token, which eliminates trigraphs, etc.
3153   bool Invalid = false;
3154   StringRef TokSpelling = PP.getSpelling(Tok, SpellingBuffer, &Invalid);
3155   if (Invalid)
3156     return ExprError();
3157 
3158   NumericLiteralParser Literal(TokSpelling, Tok.getLocation(), PP);
3159   if (Literal.hadError)
3160     return ExprError();
3161 
3162   if (Literal.hasUDSuffix()) {
3163     // We're building a user-defined literal.
3164     IdentifierInfo *UDSuffix = &Context.Idents.get(Literal.getUDSuffix());
3165     SourceLocation UDSuffixLoc =
3166       getUDSuffixLoc(*this, Tok.getLocation(), Literal.getUDSuffixOffset());
3167 
3168     // Make sure we're allowed user-defined literals here.
3169     if (!UDLScope)
3170       return ExprError(Diag(UDSuffixLoc, diag::err_invalid_numeric_udl));
3171 
3172     QualType CookedTy;
3173     if (Literal.isFloatingLiteral()) {
3174       // C++11 [lex.ext]p4: If S contains a literal operator with parameter type
3175       // long double, the literal is treated as a call of the form
3176       //   operator "" X (f L)
3177       CookedTy = Context.LongDoubleTy;
3178     } else {
3179       // C++11 [lex.ext]p3: If S contains a literal operator with parameter type
3180       // unsigned long long, the literal is treated as a call of the form
3181       //   operator "" X (n ULL)
3182       CookedTy = Context.UnsignedLongLongTy;
3183     }
3184 
3185     DeclarationName OpName =
3186       Context.DeclarationNames.getCXXLiteralOperatorName(UDSuffix);
3187     DeclarationNameInfo OpNameInfo(OpName, UDSuffixLoc);
3188     OpNameInfo.setCXXLiteralOperatorNameLoc(UDSuffixLoc);
3189 
3190     SourceLocation TokLoc = Tok.getLocation();
3191 
3192     // Perform literal operator lookup to determine if we're building a raw
3193     // literal or a cooked one.
3194     LookupResult R(*this, OpName, UDSuffixLoc, LookupOrdinaryName);
3195     switch (LookupLiteralOperator(UDLScope, R, CookedTy,
3196                                   /*AllowRaw*/true, /*AllowTemplate*/true,
3197                                   /*AllowStringTemplate*/false)) {
3198     case LOLR_Error:
3199       return ExprError();
3200 
3201     case LOLR_Cooked: {
3202       Expr *Lit;
3203       if (Literal.isFloatingLiteral()) {
3204         Lit = BuildFloatingLiteral(*this, Literal, CookedTy, Tok.getLocation());
3205       } else {
3206         llvm::APInt ResultVal(Context.getTargetInfo().getLongLongWidth(), 0);
3207         if (Literal.GetIntegerValue(ResultVal))
3208           Diag(Tok.getLocation(), diag::err_integer_literal_too_large)
3209               << /* Unsigned */ 1;
3210         Lit = IntegerLiteral::Create(Context, ResultVal, CookedTy,
3211                                      Tok.getLocation());
3212       }
3213       return BuildLiteralOperatorCall(R, OpNameInfo, Lit, TokLoc);
3214     }
3215 
3216     case LOLR_Raw: {
3217       // C++11 [lit.ext]p3, p4: If S contains a raw literal operator, the
3218       // literal is treated as a call of the form
3219       //   operator "" X ("n")
3220       unsigned Length = Literal.getUDSuffixOffset();
3221       QualType StrTy = Context.getConstantArrayType(
3222           Context.CharTy.withConst(), llvm::APInt(32, Length + 1),
3223           ArrayType::Normal, 0);
3224       Expr *Lit = StringLiteral::Create(
3225           Context, StringRef(TokSpelling.data(), Length), StringLiteral::Ascii,
3226           /*Pascal*/false, StrTy, &TokLoc, 1);
3227       return BuildLiteralOperatorCall(R, OpNameInfo, Lit, TokLoc);
3228     }
3229 
3230     case LOLR_Template: {
3231       // C++11 [lit.ext]p3, p4: Otherwise (S contains a literal operator
3232       // template), L is treated as a call fo the form
3233       //   operator "" X <'c1', 'c2', ... 'ck'>()
3234       // where n is the source character sequence c1 c2 ... ck.
3235       TemplateArgumentListInfo ExplicitArgs;
3236       unsigned CharBits = Context.getIntWidth(Context.CharTy);
3237       bool CharIsUnsigned = Context.CharTy->isUnsignedIntegerType();
3238       llvm::APSInt Value(CharBits, CharIsUnsigned);
3239       for (unsigned I = 0, N = Literal.getUDSuffixOffset(); I != N; ++I) {
3240         Value = TokSpelling[I];
3241         TemplateArgument Arg(Context, Value, Context.CharTy);
3242         TemplateArgumentLocInfo ArgInfo;
3243         ExplicitArgs.addArgument(TemplateArgumentLoc(Arg, ArgInfo));
3244       }
3245       return BuildLiteralOperatorCall(R, OpNameInfo, None, TokLoc,
3246                                       &ExplicitArgs);
3247     }
3248     case LOLR_StringTemplate:
3249       llvm_unreachable("unexpected literal operator lookup result");
3250     }
3251   }
3252 
3253   Expr *Res;
3254 
3255   if (Literal.isFloatingLiteral()) {
3256     QualType Ty;
3257     if (Literal.isFloat)
3258       Ty = Context.FloatTy;
3259     else if (!Literal.isLong)
3260       Ty = Context.DoubleTy;
3261     else
3262       Ty = Context.LongDoubleTy;
3263 
3264     Res = BuildFloatingLiteral(*this, Literal, Ty, Tok.getLocation());
3265 
3266     if (Ty == Context.DoubleTy) {
3267       if (getLangOpts().SinglePrecisionConstants) {
3268         Res = ImpCastExprToType(Res, Context.FloatTy, CK_FloatingCast).get();
3269       } else if (getLangOpts().OpenCL && !getOpenCLOptions().cl_khr_fp64) {
3270         Diag(Tok.getLocation(), diag::warn_double_const_requires_fp64);
3271         Res = ImpCastExprToType(Res, Context.FloatTy, CK_FloatingCast).get();
3272       }
3273     }
3274   } else if (!Literal.isIntegerLiteral()) {
3275     return ExprError();
3276   } else {
3277     QualType Ty;
3278 
3279     // 'long long' is a C99 or C++11 feature.
3280     if (!getLangOpts().C99 && Literal.isLongLong) {
3281       if (getLangOpts().CPlusPlus)
3282         Diag(Tok.getLocation(),
3283              getLangOpts().CPlusPlus11 ?
3284              diag::warn_cxx98_compat_longlong : diag::ext_cxx11_longlong);
3285       else
3286         Diag(Tok.getLocation(), diag::ext_c99_longlong);
3287     }
3288 
3289     // Get the value in the widest-possible width.
3290     unsigned MaxWidth = Context.getTargetInfo().getIntMaxTWidth();
3291     // The microsoft literal suffix extensions support 128-bit literals, which
3292     // may be wider than [u]intmax_t.
3293     // FIXME: Actually, they don't. We seem to have accidentally invented the
3294     //        i128 suffix.
3295     if (Literal.MicrosoftInteger == 128 && MaxWidth < 128 &&
3296         Context.getTargetInfo().hasInt128Type())
3297       MaxWidth = 128;
3298     llvm::APInt ResultVal(MaxWidth, 0);
3299 
3300     if (Literal.GetIntegerValue(ResultVal)) {
3301       // If this value didn't fit into uintmax_t, error and force to ull.
3302       Diag(Tok.getLocation(), diag::err_integer_literal_too_large)
3303           << /* Unsigned */ 1;
3304       Ty = Context.UnsignedLongLongTy;
3305       assert(Context.getTypeSize(Ty) == ResultVal.getBitWidth() &&
3306              "long long is not intmax_t?");
3307     } else {
3308       // If this value fits into a ULL, try to figure out what else it fits into
3309       // according to the rules of C99 6.4.4.1p5.
3310 
3311       // Octal, Hexadecimal, and integers with a U suffix are allowed to
3312       // be an unsigned int.
3313       bool AllowUnsigned = Literal.isUnsigned || Literal.getRadix() != 10;
3314 
3315       // Check from smallest to largest, picking the smallest type we can.
3316       unsigned Width = 0;
3317 
3318       // Microsoft specific integer suffixes are explicitly sized.
3319       if (Literal.MicrosoftInteger) {
3320         if (Literal.MicrosoftInteger > MaxWidth) {
3321           // If this target doesn't support __int128, error and force to ull.
3322           Diag(Tok.getLocation(), diag::err_int128_unsupported);
3323           Width = MaxWidth;
3324           Ty = Context.getIntMaxType();
3325         } else {
3326           Width = Literal.MicrosoftInteger;
3327           Ty = Context.getIntTypeForBitwidth(Width,
3328                                              /*Signed=*/!Literal.isUnsigned);
3329         }
3330       }
3331 
3332       if (Ty.isNull() && !Literal.isLong && !Literal.isLongLong) {
3333         // Are int/unsigned possibilities?
3334         unsigned IntSize = Context.getTargetInfo().getIntWidth();
3335 
3336         // Does it fit in a unsigned int?
3337         if (ResultVal.isIntN(IntSize)) {
3338           // Does it fit in a signed int?
3339           if (!Literal.isUnsigned && ResultVal[IntSize-1] == 0)
3340             Ty = Context.IntTy;
3341           else if (AllowUnsigned)
3342             Ty = Context.UnsignedIntTy;
3343           Width = IntSize;
3344         }
3345       }
3346 
3347       // Are long/unsigned long possibilities?
3348       if (Ty.isNull() && !Literal.isLongLong) {
3349         unsigned LongSize = Context.getTargetInfo().getLongWidth();
3350 
3351         // Does it fit in a unsigned long?
3352         if (ResultVal.isIntN(LongSize)) {
3353           // Does it fit in a signed long?
3354           if (!Literal.isUnsigned && ResultVal[LongSize-1] == 0)
3355             Ty = Context.LongTy;
3356           else if (AllowUnsigned)
3357             Ty = Context.UnsignedLongTy;
3358           Width = LongSize;
3359         }
3360       }
3361 
3362       // Check long long if needed.
3363       if (Ty.isNull()) {
3364         unsigned LongLongSize = Context.getTargetInfo().getLongLongWidth();
3365 
3366         // Does it fit in a unsigned long long?
3367         if (ResultVal.isIntN(LongLongSize)) {
3368           // Does it fit in a signed long long?
3369           // To be compatible with MSVC, hex integer literals ending with the
3370           // LL or i64 suffix are always signed in Microsoft mode.
3371           if (!Literal.isUnsigned && (ResultVal[LongLongSize-1] == 0 ||
3372               (getLangOpts().MicrosoftExt && Literal.isLongLong)))
3373             Ty = Context.LongLongTy;
3374           else if (AllowUnsigned)
3375             Ty = Context.UnsignedLongLongTy;
3376           Width = LongLongSize;
3377         }
3378       }
3379 
3380       // If we still couldn't decide a type, we probably have something that
3381       // does not fit in a signed long long, but has no U suffix.
3382       if (Ty.isNull()) {
3383         Diag(Tok.getLocation(), diag::ext_integer_literal_too_large_for_signed);
3384         Ty = Context.UnsignedLongLongTy;
3385         Width = Context.getTargetInfo().getLongLongWidth();
3386       }
3387 
3388       if (ResultVal.getBitWidth() != Width)
3389         ResultVal = ResultVal.trunc(Width);
3390     }
3391     Res = IntegerLiteral::Create(Context, ResultVal, Ty, Tok.getLocation());
3392   }
3393 
3394   // If this is an imaginary literal, create the ImaginaryLiteral wrapper.
3395   if (Literal.isImaginary)
3396     Res = new (Context) ImaginaryLiteral(Res,
3397                                         Context.getComplexType(Res->getType()));
3398 
3399   return Res;
3400 }
3401 
ActOnParenExpr(SourceLocation L,SourceLocation R,Expr * E)3402 ExprResult Sema::ActOnParenExpr(SourceLocation L, SourceLocation R, Expr *E) {
3403   assert(E && "ActOnParenExpr() missing expr");
3404   return new (Context) ParenExpr(L, R, E);
3405 }
3406 
CheckVecStepTraitOperandType(Sema & S,QualType T,SourceLocation Loc,SourceRange ArgRange)3407 static bool CheckVecStepTraitOperandType(Sema &S, QualType T,
3408                                          SourceLocation Loc,
3409                                          SourceRange ArgRange) {
3410   // [OpenCL 1.1 6.11.12] "The vec_step built-in function takes a built-in
3411   // scalar or vector data type argument..."
3412   // Every built-in scalar type (OpenCL 1.1 6.1.1) is either an arithmetic
3413   // type (C99 6.2.5p18) or void.
3414   if (!(T->isArithmeticType() || T->isVoidType() || T->isVectorType())) {
3415     S.Diag(Loc, diag::err_vecstep_non_scalar_vector_type)
3416       << T << ArgRange;
3417     return true;
3418   }
3419 
3420   assert((T->isVoidType() || !T->isIncompleteType()) &&
3421          "Scalar types should always be complete");
3422   return false;
3423 }
3424 
CheckExtensionTraitOperandType(Sema & S,QualType T,SourceLocation Loc,SourceRange ArgRange,UnaryExprOrTypeTrait TraitKind)3425 static bool CheckExtensionTraitOperandType(Sema &S, QualType T,
3426                                            SourceLocation Loc,
3427                                            SourceRange ArgRange,
3428                                            UnaryExprOrTypeTrait TraitKind) {
3429   // Invalid types must be hard errors for SFINAE in C++.
3430   if (S.LangOpts.CPlusPlus)
3431     return true;
3432 
3433   // C99 6.5.3.4p1:
3434   if (T->isFunctionType() &&
3435       (TraitKind == UETT_SizeOf || TraitKind == UETT_AlignOf)) {
3436     // sizeof(function)/alignof(function) is allowed as an extension.
3437     S.Diag(Loc, diag::ext_sizeof_alignof_function_type)
3438       << TraitKind << ArgRange;
3439     return false;
3440   }
3441 
3442   // Allow sizeof(void)/alignof(void) as an extension, unless in OpenCL where
3443   // this is an error (OpenCL v1.1 s6.3.k)
3444   if (T->isVoidType()) {
3445     unsigned DiagID = S.LangOpts.OpenCL ? diag::err_opencl_sizeof_alignof_type
3446                                         : diag::ext_sizeof_alignof_void_type;
3447     S.Diag(Loc, DiagID) << TraitKind << ArgRange;
3448     return false;
3449   }
3450 
3451   return true;
3452 }
3453 
CheckObjCTraitOperandConstraints(Sema & S,QualType T,SourceLocation Loc,SourceRange ArgRange,UnaryExprOrTypeTrait TraitKind)3454 static bool CheckObjCTraitOperandConstraints(Sema &S, QualType T,
3455                                              SourceLocation Loc,
3456                                              SourceRange ArgRange,
3457                                              UnaryExprOrTypeTrait TraitKind) {
3458   // Reject sizeof(interface) and sizeof(interface<proto>) if the
3459   // runtime doesn't allow it.
3460   if (!S.LangOpts.ObjCRuntime.allowsSizeofAlignof() && T->isObjCObjectType()) {
3461     S.Diag(Loc, diag::err_sizeof_nonfragile_interface)
3462       << T << (TraitKind == UETT_SizeOf)
3463       << ArgRange;
3464     return true;
3465   }
3466 
3467   return false;
3468 }
3469 
3470 /// \brief Check whether E is a pointer from a decayed array type (the decayed
3471 /// pointer type is equal to T) and emit a warning if it is.
warnOnSizeofOnArrayDecay(Sema & S,SourceLocation Loc,QualType T,Expr * E)3472 static void warnOnSizeofOnArrayDecay(Sema &S, SourceLocation Loc, QualType T,
3473                                      Expr *E) {
3474   // Don't warn if the operation changed the type.
3475   if (T != E->getType())
3476     return;
3477 
3478   // Now look for array decays.
3479   ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E);
3480   if (!ICE || ICE->getCastKind() != CK_ArrayToPointerDecay)
3481     return;
3482 
3483   S.Diag(Loc, diag::warn_sizeof_array_decay) << ICE->getSourceRange()
3484                                              << ICE->getType()
3485                                              << ICE->getSubExpr()->getType();
3486 }
3487 
3488 /// \brief Check the constraints on expression operands to unary type expression
3489 /// and type traits.
3490 ///
3491 /// Completes any types necessary and validates the constraints on the operand
3492 /// expression. The logic mostly mirrors the type-based overload, but may modify
3493 /// the expression as it completes the type for that expression through template
3494 /// instantiation, etc.
CheckUnaryExprOrTypeTraitOperand(Expr * E,UnaryExprOrTypeTrait ExprKind)3495 bool Sema::CheckUnaryExprOrTypeTraitOperand(Expr *E,
3496                                             UnaryExprOrTypeTrait ExprKind) {
3497   QualType ExprTy = E->getType();
3498   assert(!ExprTy->isReferenceType());
3499 
3500   if (ExprKind == UETT_VecStep)
3501     return CheckVecStepTraitOperandType(*this, ExprTy, E->getExprLoc(),
3502                                         E->getSourceRange());
3503 
3504   // Whitelist some types as extensions
3505   if (!CheckExtensionTraitOperandType(*this, ExprTy, E->getExprLoc(),
3506                                       E->getSourceRange(), ExprKind))
3507     return false;
3508 
3509   // 'alignof' applied to an expression only requires the base element type of
3510   // the expression to be complete. 'sizeof' requires the expression's type to
3511   // be complete (and will attempt to complete it if it's an array of unknown
3512   // bound).
3513   if (ExprKind == UETT_AlignOf) {
3514     if (RequireCompleteType(E->getExprLoc(),
3515                             Context.getBaseElementType(E->getType()),
3516                             diag::err_sizeof_alignof_incomplete_type, ExprKind,
3517                             E->getSourceRange()))
3518       return true;
3519   } else {
3520     if (RequireCompleteExprType(E, diag::err_sizeof_alignof_incomplete_type,
3521                                 ExprKind, E->getSourceRange()))
3522       return true;
3523   }
3524 
3525   // Completing the expression's type may have changed it.
3526   ExprTy = E->getType();
3527   assert(!ExprTy->isReferenceType());
3528 
3529   if (ExprTy->isFunctionType()) {
3530     Diag(E->getExprLoc(), diag::err_sizeof_alignof_function_type)
3531       << ExprKind << E->getSourceRange();
3532     return true;
3533   }
3534 
3535   // The operand for sizeof and alignof is in an unevaluated expression context,
3536   // so side effects could result in unintended consequences.
3537   if ((ExprKind == UETT_SizeOf || ExprKind == UETT_AlignOf) &&
3538       ActiveTemplateInstantiations.empty() && E->HasSideEffects(Context, false))
3539     Diag(E->getExprLoc(), diag::warn_side_effects_unevaluated_context);
3540 
3541   if (CheckObjCTraitOperandConstraints(*this, ExprTy, E->getExprLoc(),
3542                                        E->getSourceRange(), ExprKind))
3543     return true;
3544 
3545   if (ExprKind == UETT_SizeOf) {
3546     if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(E->IgnoreParens())) {
3547       if (ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(DeclRef->getFoundDecl())) {
3548         QualType OType = PVD->getOriginalType();
3549         QualType Type = PVD->getType();
3550         if (Type->isPointerType() && OType->isArrayType()) {
3551           Diag(E->getExprLoc(), diag::warn_sizeof_array_param)
3552             << Type << OType;
3553           Diag(PVD->getLocation(), diag::note_declared_at);
3554         }
3555       }
3556     }
3557 
3558     // Warn on "sizeof(array op x)" and "sizeof(x op array)", where the array
3559     // decays into a pointer and returns an unintended result. This is most
3560     // likely a typo for "sizeof(array) op x".
3561     if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E->IgnoreParens())) {
3562       warnOnSizeofOnArrayDecay(*this, BO->getOperatorLoc(), BO->getType(),
3563                                BO->getLHS());
3564       warnOnSizeofOnArrayDecay(*this, BO->getOperatorLoc(), BO->getType(),
3565                                BO->getRHS());
3566     }
3567   }
3568 
3569   return false;
3570 }
3571 
3572 /// \brief Check the constraints on operands to unary expression and type
3573 /// traits.
3574 ///
3575 /// This will complete any types necessary, and validate the various constraints
3576 /// on those operands.
3577 ///
3578 /// The UsualUnaryConversions() function is *not* called by this routine.
3579 /// C99 6.3.2.1p[2-4] all state:
3580 ///   Except when it is the operand of the sizeof operator ...
3581 ///
3582 /// C++ [expr.sizeof]p4
3583 ///   The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
3584 ///   standard conversions are not applied to the operand of sizeof.
3585 ///
3586 /// This policy is followed for all of the unary trait expressions.
CheckUnaryExprOrTypeTraitOperand(QualType ExprType,SourceLocation OpLoc,SourceRange ExprRange,UnaryExprOrTypeTrait ExprKind)3587 bool Sema::CheckUnaryExprOrTypeTraitOperand(QualType ExprType,
3588                                             SourceLocation OpLoc,
3589                                             SourceRange ExprRange,
3590                                             UnaryExprOrTypeTrait ExprKind) {
3591   if (ExprType->isDependentType())
3592     return false;
3593 
3594   // C++ [expr.sizeof]p2:
3595   //     When applied to a reference or a reference type, the result
3596   //     is the size of the referenced type.
3597   // C++11 [expr.alignof]p3:
3598   //     When alignof is applied to a reference type, the result
3599   //     shall be the alignment of the referenced type.
3600   if (const ReferenceType *Ref = ExprType->getAs<ReferenceType>())
3601     ExprType = Ref->getPointeeType();
3602 
3603   // C11 6.5.3.4/3, C++11 [expr.alignof]p3:
3604   //   When alignof or _Alignof is applied to an array type, the result
3605   //   is the alignment of the element type.
3606   if (ExprKind == UETT_AlignOf)
3607     ExprType = Context.getBaseElementType(ExprType);
3608 
3609   if (ExprKind == UETT_VecStep)
3610     return CheckVecStepTraitOperandType(*this, ExprType, OpLoc, ExprRange);
3611 
3612   // Whitelist some types as extensions
3613   if (!CheckExtensionTraitOperandType(*this, ExprType, OpLoc, ExprRange,
3614                                       ExprKind))
3615     return false;
3616 
3617   if (RequireCompleteType(OpLoc, ExprType,
3618                           diag::err_sizeof_alignof_incomplete_type,
3619                           ExprKind, ExprRange))
3620     return true;
3621 
3622   if (ExprType->isFunctionType()) {
3623     Diag(OpLoc, diag::err_sizeof_alignof_function_type)
3624       << ExprKind << ExprRange;
3625     return true;
3626   }
3627 
3628   if (CheckObjCTraitOperandConstraints(*this, ExprType, OpLoc, ExprRange,
3629                                        ExprKind))
3630     return true;
3631 
3632   return false;
3633 }
3634 
CheckAlignOfExpr(Sema & S,Expr * E)3635 static bool CheckAlignOfExpr(Sema &S, Expr *E) {
3636   E = E->IgnoreParens();
3637 
3638   // Cannot know anything else if the expression is dependent.
3639   if (E->isTypeDependent())
3640     return false;
3641 
3642   if (E->getObjectKind() == OK_BitField) {
3643     S.Diag(E->getExprLoc(), diag::err_sizeof_alignof_bitfield)
3644        << 1 << E->getSourceRange();
3645     return true;
3646   }
3647 
3648   ValueDecl *D = nullptr;
3649   if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
3650     D = DRE->getDecl();
3651   } else if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
3652     D = ME->getMemberDecl();
3653   }
3654 
3655   // If it's a field, require the containing struct to have a
3656   // complete definition so that we can compute the layout.
3657   //
3658   // This can happen in C++11 onwards, either by naming the member
3659   // in a way that is not transformed into a member access expression
3660   // (in an unevaluated operand, for instance), or by naming the member
3661   // in a trailing-return-type.
3662   //
3663   // For the record, since __alignof__ on expressions is a GCC
3664   // extension, GCC seems to permit this but always gives the
3665   // nonsensical answer 0.
3666   //
3667   // We don't really need the layout here --- we could instead just
3668   // directly check for all the appropriate alignment-lowing
3669   // attributes --- but that would require duplicating a lot of
3670   // logic that just isn't worth duplicating for such a marginal
3671   // use-case.
3672   if (FieldDecl *FD = dyn_cast_or_null<FieldDecl>(D)) {
3673     // Fast path this check, since we at least know the record has a
3674     // definition if we can find a member of it.
3675     if (!FD->getParent()->isCompleteDefinition()) {
3676       S.Diag(E->getExprLoc(), diag::err_alignof_member_of_incomplete_type)
3677         << E->getSourceRange();
3678       return true;
3679     }
3680 
3681     // Otherwise, if it's a field, and the field doesn't have
3682     // reference type, then it must have a complete type (or be a
3683     // flexible array member, which we explicitly want to
3684     // white-list anyway), which makes the following checks trivial.
3685     if (!FD->getType()->isReferenceType())
3686       return false;
3687   }
3688 
3689   return S.CheckUnaryExprOrTypeTraitOperand(E, UETT_AlignOf);
3690 }
3691 
CheckVecStepExpr(Expr * E)3692 bool Sema::CheckVecStepExpr(Expr *E) {
3693   E = E->IgnoreParens();
3694 
3695   // Cannot know anything else if the expression is dependent.
3696   if (E->isTypeDependent())
3697     return false;
3698 
3699   return CheckUnaryExprOrTypeTraitOperand(E, UETT_VecStep);
3700 }
3701 
3702 /// \brief Build a sizeof or alignof expression given a type operand.
3703 ExprResult
CreateUnaryExprOrTypeTraitExpr(TypeSourceInfo * TInfo,SourceLocation OpLoc,UnaryExprOrTypeTrait ExprKind,SourceRange R)3704 Sema::CreateUnaryExprOrTypeTraitExpr(TypeSourceInfo *TInfo,
3705                                      SourceLocation OpLoc,
3706                                      UnaryExprOrTypeTrait ExprKind,
3707                                      SourceRange R) {
3708   if (!TInfo)
3709     return ExprError();
3710 
3711   QualType T = TInfo->getType();
3712 
3713   if (!T->isDependentType() &&
3714       CheckUnaryExprOrTypeTraitOperand(T, OpLoc, R, ExprKind))
3715     return ExprError();
3716 
3717   // C99 6.5.3.4p4: the type (an unsigned integer type) is size_t.
3718   return new (Context) UnaryExprOrTypeTraitExpr(
3719       ExprKind, TInfo, Context.getSizeType(), OpLoc, R.getEnd());
3720 }
3721 
3722 /// \brief Build a sizeof or alignof expression given an expression
3723 /// operand.
3724 ExprResult
CreateUnaryExprOrTypeTraitExpr(Expr * E,SourceLocation OpLoc,UnaryExprOrTypeTrait ExprKind)3725 Sema::CreateUnaryExprOrTypeTraitExpr(Expr *E, SourceLocation OpLoc,
3726                                      UnaryExprOrTypeTrait ExprKind) {
3727   ExprResult PE = CheckPlaceholderExpr(E);
3728   if (PE.isInvalid())
3729     return ExprError();
3730 
3731   E = PE.get();
3732 
3733   // Verify that the operand is valid.
3734   bool isInvalid = false;
3735   if (E->isTypeDependent()) {
3736     // Delay type-checking for type-dependent expressions.
3737   } else if (ExprKind == UETT_AlignOf) {
3738     isInvalid = CheckAlignOfExpr(*this, E);
3739   } else if (ExprKind == UETT_VecStep) {
3740     isInvalid = CheckVecStepExpr(E);
3741   } else if (E->refersToBitField()) {  // C99 6.5.3.4p1.
3742     Diag(E->getExprLoc(), diag::err_sizeof_alignof_bitfield) << 0;
3743     isInvalid = true;
3744   } else {
3745     isInvalid = CheckUnaryExprOrTypeTraitOperand(E, UETT_SizeOf);
3746   }
3747 
3748   if (isInvalid)
3749     return ExprError();
3750 
3751   if (ExprKind == UETT_SizeOf && E->getType()->isVariableArrayType()) {
3752     PE = TransformToPotentiallyEvaluated(E);
3753     if (PE.isInvalid()) return ExprError();
3754     E = PE.get();
3755   }
3756 
3757   // C99 6.5.3.4p4: the type (an unsigned integer type) is size_t.
3758   return new (Context) UnaryExprOrTypeTraitExpr(
3759       ExprKind, E, Context.getSizeType(), OpLoc, E->getSourceRange().getEnd());
3760 }
3761 
3762 /// ActOnUnaryExprOrTypeTraitExpr - Handle @c sizeof(type) and @c sizeof @c
3763 /// expr and the same for @c alignof and @c __alignof
3764 /// Note that the ArgRange is invalid if isType is false.
3765 ExprResult
ActOnUnaryExprOrTypeTraitExpr(SourceLocation OpLoc,UnaryExprOrTypeTrait ExprKind,bool IsType,void * TyOrEx,const SourceRange & ArgRange)3766 Sema::ActOnUnaryExprOrTypeTraitExpr(SourceLocation OpLoc,
3767                                     UnaryExprOrTypeTrait ExprKind, bool IsType,
3768                                     void *TyOrEx, const SourceRange &ArgRange) {
3769   // If error parsing type, ignore.
3770   if (!TyOrEx) return ExprError();
3771 
3772   if (IsType) {
3773     TypeSourceInfo *TInfo;
3774     (void) GetTypeFromParser(ParsedType::getFromOpaquePtr(TyOrEx), &TInfo);
3775     return CreateUnaryExprOrTypeTraitExpr(TInfo, OpLoc, ExprKind, ArgRange);
3776   }
3777 
3778   Expr *ArgEx = (Expr *)TyOrEx;
3779   ExprResult Result = CreateUnaryExprOrTypeTraitExpr(ArgEx, OpLoc, ExprKind);
3780   return Result;
3781 }
3782 
CheckRealImagOperand(Sema & S,ExprResult & V,SourceLocation Loc,bool IsReal)3783 static QualType CheckRealImagOperand(Sema &S, ExprResult &V, SourceLocation Loc,
3784                                      bool IsReal) {
3785   if (V.get()->isTypeDependent())
3786     return S.Context.DependentTy;
3787 
3788   // _Real and _Imag are only l-values for normal l-values.
3789   if (V.get()->getObjectKind() != OK_Ordinary) {
3790     V = S.DefaultLvalueConversion(V.get());
3791     if (V.isInvalid())
3792       return QualType();
3793   }
3794 
3795   // These operators return the element type of a complex type.
3796   if (const ComplexType *CT = V.get()->getType()->getAs<ComplexType>())
3797     return CT->getElementType();
3798 
3799   // Otherwise they pass through real integer and floating point types here.
3800   if (V.get()->getType()->isArithmeticType())
3801     return V.get()->getType();
3802 
3803   // Test for placeholders.
3804   ExprResult PR = S.CheckPlaceholderExpr(V.get());
3805   if (PR.isInvalid()) return QualType();
3806   if (PR.get() != V.get()) {
3807     V = PR;
3808     return CheckRealImagOperand(S, V, Loc, IsReal);
3809   }
3810 
3811   // Reject anything else.
3812   S.Diag(Loc, diag::err_realimag_invalid_type) << V.get()->getType()
3813     << (IsReal ? "__real" : "__imag");
3814   return QualType();
3815 }
3816 
3817 
3818 
3819 ExprResult
ActOnPostfixUnaryOp(Scope * S,SourceLocation OpLoc,tok::TokenKind Kind,Expr * Input)3820 Sema::ActOnPostfixUnaryOp(Scope *S, SourceLocation OpLoc,
3821                           tok::TokenKind Kind, Expr *Input) {
3822   UnaryOperatorKind Opc;
3823   switch (Kind) {
3824   default: llvm_unreachable("Unknown unary op!");
3825   case tok::plusplus:   Opc = UO_PostInc; break;
3826   case tok::minusminus: Opc = UO_PostDec; break;
3827   }
3828 
3829   // Since this might is a postfix expression, get rid of ParenListExprs.
3830   ExprResult Result = MaybeConvertParenListExprToParenExpr(S, Input);
3831   if (Result.isInvalid()) return ExprError();
3832   Input = Result.get();
3833 
3834   return BuildUnaryOp(S, OpLoc, Opc, Input);
3835 }
3836 
3837 /// \brief Diagnose if arithmetic on the given ObjC pointer is illegal.
3838 ///
3839 /// \return true on error
checkArithmeticOnObjCPointer(Sema & S,SourceLocation opLoc,Expr * op)3840 static bool checkArithmeticOnObjCPointer(Sema &S,
3841                                          SourceLocation opLoc,
3842                                          Expr *op) {
3843   assert(op->getType()->isObjCObjectPointerType());
3844   if (S.LangOpts.ObjCRuntime.allowsPointerArithmetic() &&
3845       !S.LangOpts.ObjCSubscriptingLegacyRuntime)
3846     return false;
3847 
3848   S.Diag(opLoc, diag::err_arithmetic_nonfragile_interface)
3849     << op->getType()->castAs<ObjCObjectPointerType>()->getPointeeType()
3850     << op->getSourceRange();
3851   return true;
3852 }
3853 
3854 ExprResult
ActOnArraySubscriptExpr(Scope * S,Expr * base,SourceLocation lbLoc,Expr * idx,SourceLocation rbLoc)3855 Sema::ActOnArraySubscriptExpr(Scope *S, Expr *base, SourceLocation lbLoc,
3856                               Expr *idx, SourceLocation rbLoc) {
3857   // Since this might be a postfix expression, get rid of ParenListExprs.
3858   if (isa<ParenListExpr>(base)) {
3859     ExprResult result = MaybeConvertParenListExprToParenExpr(S, base);
3860     if (result.isInvalid()) return ExprError();
3861     base = result.get();
3862   }
3863 
3864   // Handle any non-overload placeholder types in the base and index
3865   // expressions.  We can't handle overloads here because the other
3866   // operand might be an overloadable type, in which case the overload
3867   // resolution for the operator overload should get the first crack
3868   // at the overload.
3869   if (base->getType()->isNonOverloadPlaceholderType()) {
3870     ExprResult result = CheckPlaceholderExpr(base);
3871     if (result.isInvalid()) return ExprError();
3872     base = result.get();
3873   }
3874   if (idx->getType()->isNonOverloadPlaceholderType()) {
3875     ExprResult result = CheckPlaceholderExpr(idx);
3876     if (result.isInvalid()) return ExprError();
3877     idx = result.get();
3878   }
3879 
3880   // Build an unanalyzed expression if either operand is type-dependent.
3881   if (getLangOpts().CPlusPlus &&
3882       (base->isTypeDependent() || idx->isTypeDependent())) {
3883     return new (Context) ArraySubscriptExpr(base, idx, Context.DependentTy,
3884                                             VK_LValue, OK_Ordinary, rbLoc);
3885   }
3886 
3887   // Use C++ overloaded-operator rules if either operand has record
3888   // type.  The spec says to do this if either type is *overloadable*,
3889   // but enum types can't declare subscript operators or conversion
3890   // operators, so there's nothing interesting for overload resolution
3891   // to do if there aren't any record types involved.
3892   //
3893   // ObjC pointers have their own subscripting logic that is not tied
3894   // to overload resolution and so should not take this path.
3895   if (getLangOpts().CPlusPlus &&
3896       (base->getType()->isRecordType() ||
3897        (!base->getType()->isObjCObjectPointerType() &&
3898         idx->getType()->isRecordType()))) {
3899     return CreateOverloadedArraySubscriptExpr(lbLoc, rbLoc, base, idx);
3900   }
3901 
3902   return CreateBuiltinArraySubscriptExpr(base, lbLoc, idx, rbLoc);
3903 }
3904 
3905 ExprResult
CreateBuiltinArraySubscriptExpr(Expr * Base,SourceLocation LLoc,Expr * Idx,SourceLocation RLoc)3906 Sema::CreateBuiltinArraySubscriptExpr(Expr *Base, SourceLocation LLoc,
3907                                       Expr *Idx, SourceLocation RLoc) {
3908   Expr *LHSExp = Base;
3909   Expr *RHSExp = Idx;
3910 
3911   // Perform default conversions.
3912   if (!LHSExp->getType()->getAs<VectorType>()) {
3913     ExprResult Result = DefaultFunctionArrayLvalueConversion(LHSExp);
3914     if (Result.isInvalid())
3915       return ExprError();
3916     LHSExp = Result.get();
3917   }
3918   ExprResult Result = DefaultFunctionArrayLvalueConversion(RHSExp);
3919   if (Result.isInvalid())
3920     return ExprError();
3921   RHSExp = Result.get();
3922 
3923   QualType LHSTy = LHSExp->getType(), RHSTy = RHSExp->getType();
3924   ExprValueKind VK = VK_LValue;
3925   ExprObjectKind OK = OK_Ordinary;
3926 
3927   // C99 6.5.2.1p2: the expression e1[e2] is by definition precisely equivalent
3928   // to the expression *((e1)+(e2)). This means the array "Base" may actually be
3929   // in the subscript position. As a result, we need to derive the array base
3930   // and index from the expression types.
3931   Expr *BaseExpr, *IndexExpr;
3932   QualType ResultType;
3933   if (LHSTy->isDependentType() || RHSTy->isDependentType()) {
3934     BaseExpr = LHSExp;
3935     IndexExpr = RHSExp;
3936     ResultType = Context.DependentTy;
3937   } else if (const PointerType *PTy = LHSTy->getAs<PointerType>()) {
3938     BaseExpr = LHSExp;
3939     IndexExpr = RHSExp;
3940     ResultType = PTy->getPointeeType();
3941   } else if (const ObjCObjectPointerType *PTy =
3942                LHSTy->getAs<ObjCObjectPointerType>()) {
3943     BaseExpr = LHSExp;
3944     IndexExpr = RHSExp;
3945 
3946     // Use custom logic if this should be the pseudo-object subscript
3947     // expression.
3948     if (!LangOpts.isSubscriptPointerArithmetic())
3949       return BuildObjCSubscriptExpression(RLoc, BaseExpr, IndexExpr, nullptr,
3950                                           nullptr);
3951 
3952     ResultType = PTy->getPointeeType();
3953   } else if (const PointerType *PTy = RHSTy->getAs<PointerType>()) {
3954      // Handle the uncommon case of "123[Ptr]".
3955     BaseExpr = RHSExp;
3956     IndexExpr = LHSExp;
3957     ResultType = PTy->getPointeeType();
3958   } else if (const ObjCObjectPointerType *PTy =
3959                RHSTy->getAs<ObjCObjectPointerType>()) {
3960      // Handle the uncommon case of "123[Ptr]".
3961     BaseExpr = RHSExp;
3962     IndexExpr = LHSExp;
3963     ResultType = PTy->getPointeeType();
3964     if (!LangOpts.isSubscriptPointerArithmetic()) {
3965       Diag(LLoc, diag::err_subscript_nonfragile_interface)
3966         << ResultType << BaseExpr->getSourceRange();
3967       return ExprError();
3968     }
3969   } else if (const VectorType *VTy = LHSTy->getAs<VectorType>()) {
3970     BaseExpr = LHSExp;    // vectors: V[123]
3971     IndexExpr = RHSExp;
3972     VK = LHSExp->getValueKind();
3973     if (VK != VK_RValue)
3974       OK = OK_VectorComponent;
3975 
3976     // FIXME: need to deal with const...
3977     ResultType = VTy->getElementType();
3978   } else if (LHSTy->isArrayType()) {
3979     // If we see an array that wasn't promoted by
3980     // DefaultFunctionArrayLvalueConversion, it must be an array that
3981     // wasn't promoted because of the C90 rule that doesn't
3982     // allow promoting non-lvalue arrays.  Warn, then
3983     // force the promotion here.
3984     Diag(LHSExp->getLocStart(), diag::ext_subscript_non_lvalue) <<
3985         LHSExp->getSourceRange();
3986     LHSExp = ImpCastExprToType(LHSExp, Context.getArrayDecayedType(LHSTy),
3987                                CK_ArrayToPointerDecay).get();
3988     LHSTy = LHSExp->getType();
3989 
3990     BaseExpr = LHSExp;
3991     IndexExpr = RHSExp;
3992     ResultType = LHSTy->getAs<PointerType>()->getPointeeType();
3993   } else if (RHSTy->isArrayType()) {
3994     // Same as previous, except for 123[f().a] case
3995     Diag(RHSExp->getLocStart(), diag::ext_subscript_non_lvalue) <<
3996         RHSExp->getSourceRange();
3997     RHSExp = ImpCastExprToType(RHSExp, Context.getArrayDecayedType(RHSTy),
3998                                CK_ArrayToPointerDecay).get();
3999     RHSTy = RHSExp->getType();
4000 
4001     BaseExpr = RHSExp;
4002     IndexExpr = LHSExp;
4003     ResultType = RHSTy->getAs<PointerType>()->getPointeeType();
4004   } else {
4005     return ExprError(Diag(LLoc, diag::err_typecheck_subscript_value)
4006        << LHSExp->getSourceRange() << RHSExp->getSourceRange());
4007   }
4008   // C99 6.5.2.1p1
4009   if (!IndexExpr->getType()->isIntegerType() && !IndexExpr->isTypeDependent())
4010     return ExprError(Diag(LLoc, diag::err_typecheck_subscript_not_integer)
4011                      << IndexExpr->getSourceRange());
4012 
4013   if ((IndexExpr->getType()->isSpecificBuiltinType(BuiltinType::Char_S) ||
4014        IndexExpr->getType()->isSpecificBuiltinType(BuiltinType::Char_U))
4015          && !IndexExpr->isTypeDependent())
4016     Diag(LLoc, diag::warn_subscript_is_char) << IndexExpr->getSourceRange();
4017 
4018   // C99 6.5.2.1p1: "shall have type "pointer to *object* type". Similarly,
4019   // C++ [expr.sub]p1: The type "T" shall be a completely-defined object
4020   // type. Note that Functions are not objects, and that (in C99 parlance)
4021   // incomplete types are not object types.
4022   if (ResultType->isFunctionType()) {
4023     Diag(BaseExpr->getLocStart(), diag::err_subscript_function_type)
4024       << ResultType << BaseExpr->getSourceRange();
4025     return ExprError();
4026   }
4027 
4028   if (ResultType->isVoidType() && !getLangOpts().CPlusPlus) {
4029     // GNU extension: subscripting on pointer to void
4030     Diag(LLoc, diag::ext_gnu_subscript_void_type)
4031       << BaseExpr->getSourceRange();
4032 
4033     // C forbids expressions of unqualified void type from being l-values.
4034     // See IsCForbiddenLValueType.
4035     if (!ResultType.hasQualifiers()) VK = VK_RValue;
4036   } else if (!ResultType->isDependentType() &&
4037       RequireCompleteType(LLoc, ResultType,
4038                           diag::err_subscript_incomplete_type, BaseExpr))
4039     return ExprError();
4040 
4041   assert(VK == VK_RValue || LangOpts.CPlusPlus ||
4042          !ResultType.isCForbiddenLValueType());
4043 
4044   return new (Context)
4045       ArraySubscriptExpr(LHSExp, RHSExp, ResultType, VK, OK, RLoc);
4046 }
4047 
BuildCXXDefaultArgExpr(SourceLocation CallLoc,FunctionDecl * FD,ParmVarDecl * Param)4048 ExprResult Sema::BuildCXXDefaultArgExpr(SourceLocation CallLoc,
4049                                         FunctionDecl *FD,
4050                                         ParmVarDecl *Param) {
4051   if (Param->hasUnparsedDefaultArg()) {
4052     Diag(CallLoc,
4053          diag::err_use_of_default_argument_to_function_declared_later) <<
4054       FD << cast<CXXRecordDecl>(FD->getDeclContext())->getDeclName();
4055     Diag(UnparsedDefaultArgLocs[Param],
4056          diag::note_default_argument_declared_here);
4057     return ExprError();
4058   }
4059 
4060   if (Param->hasUninstantiatedDefaultArg()) {
4061     Expr *UninstExpr = Param->getUninstantiatedDefaultArg();
4062 
4063     EnterExpressionEvaluationContext EvalContext(*this, PotentiallyEvaluated,
4064                                                  Param);
4065 
4066     // Instantiate the expression.
4067     MultiLevelTemplateArgumentList MutiLevelArgList
4068       = getTemplateInstantiationArgs(FD, nullptr, /*RelativeToPrimary=*/true);
4069 
4070     InstantiatingTemplate Inst(*this, CallLoc, Param,
4071                                MutiLevelArgList.getInnermost());
4072     if (Inst.isInvalid())
4073       return ExprError();
4074 
4075     ExprResult Result;
4076     {
4077       // C++ [dcl.fct.default]p5:
4078       //   The names in the [default argument] expression are bound, and
4079       //   the semantic constraints are checked, at the point where the
4080       //   default argument expression appears.
4081       ContextRAII SavedContext(*this, FD);
4082       LocalInstantiationScope Local(*this);
4083       Result = SubstExpr(UninstExpr, MutiLevelArgList);
4084     }
4085     if (Result.isInvalid())
4086       return ExprError();
4087 
4088     // Check the expression as an initializer for the parameter.
4089     InitializedEntity Entity
4090       = InitializedEntity::InitializeParameter(Context, Param);
4091     InitializationKind Kind
4092       = InitializationKind::CreateCopy(Param->getLocation(),
4093              /*FIXME:EqualLoc*/UninstExpr->getLocStart());
4094     Expr *ResultE = Result.getAs<Expr>();
4095 
4096     InitializationSequence InitSeq(*this, Entity, Kind, ResultE);
4097     Result = InitSeq.Perform(*this, Entity, Kind, ResultE);
4098     if (Result.isInvalid())
4099       return ExprError();
4100 
4101     Expr *Arg = Result.getAs<Expr>();
4102     CheckCompletedExpr(Arg, Param->getOuterLocStart());
4103     // Build the default argument expression.
4104     return CXXDefaultArgExpr::Create(Context, CallLoc, Param, Arg);
4105   }
4106 
4107   // If the default expression creates temporaries, we need to
4108   // push them to the current stack of expression temporaries so they'll
4109   // be properly destroyed.
4110   // FIXME: We should really be rebuilding the default argument with new
4111   // bound temporaries; see the comment in PR5810.
4112   // We don't need to do that with block decls, though, because
4113   // blocks in default argument expression can never capture anything.
4114   if (isa<ExprWithCleanups>(Param->getInit())) {
4115     // Set the "needs cleanups" bit regardless of whether there are
4116     // any explicit objects.
4117     ExprNeedsCleanups = true;
4118 
4119     // Append all the objects to the cleanup list.  Right now, this
4120     // should always be a no-op, because blocks in default argument
4121     // expressions should never be able to capture anything.
4122     assert(!cast<ExprWithCleanups>(Param->getInit())->getNumObjects() &&
4123            "default argument expression has capturing blocks?");
4124   }
4125 
4126   // We already type-checked the argument, so we know it works.
4127   // Just mark all of the declarations in this potentially-evaluated expression
4128   // as being "referenced".
4129   MarkDeclarationsReferencedInExpr(Param->getDefaultArg(),
4130                                    /*SkipLocalVariables=*/true);
4131   return CXXDefaultArgExpr::Create(Context, CallLoc, Param);
4132 }
4133 
4134 
4135 Sema::VariadicCallType
getVariadicCallType(FunctionDecl * FDecl,const FunctionProtoType * Proto,Expr * Fn)4136 Sema::getVariadicCallType(FunctionDecl *FDecl, const FunctionProtoType *Proto,
4137                           Expr *Fn) {
4138   if (Proto && Proto->isVariadic()) {
4139     if (dyn_cast_or_null<CXXConstructorDecl>(FDecl))
4140       return VariadicConstructor;
4141     else if (Fn && Fn->getType()->isBlockPointerType())
4142       return VariadicBlock;
4143     else if (FDecl) {
4144       if (CXXMethodDecl *Method = dyn_cast_or_null<CXXMethodDecl>(FDecl))
4145         if (Method->isInstance())
4146           return VariadicMethod;
4147     } else if (Fn && Fn->getType() == Context.BoundMemberTy)
4148       return VariadicMethod;
4149     return VariadicFunction;
4150   }
4151   return VariadicDoesNotApply;
4152 }
4153 
4154 namespace {
4155 class FunctionCallCCC : public FunctionCallFilterCCC {
4156 public:
FunctionCallCCC(Sema & SemaRef,const IdentifierInfo * FuncName,unsigned NumArgs,MemberExpr * ME)4157   FunctionCallCCC(Sema &SemaRef, const IdentifierInfo *FuncName,
4158                   unsigned NumArgs, MemberExpr *ME)
4159       : FunctionCallFilterCCC(SemaRef, NumArgs, false, ME),
4160         FunctionName(FuncName) {}
4161 
ValidateCandidate(const TypoCorrection & candidate)4162   bool ValidateCandidate(const TypoCorrection &candidate) override {
4163     if (!candidate.getCorrectionSpecifier() ||
4164         candidate.getCorrectionAsIdentifierInfo() != FunctionName) {
4165       return false;
4166     }
4167 
4168     return FunctionCallFilterCCC::ValidateCandidate(candidate);
4169   }
4170 
4171 private:
4172   const IdentifierInfo *const FunctionName;
4173 };
4174 }
4175 
TryTypoCorrectionForCall(Sema & S,Expr * Fn,FunctionDecl * FDecl,ArrayRef<Expr * > Args)4176 static TypoCorrection TryTypoCorrectionForCall(Sema &S, Expr *Fn,
4177                                                FunctionDecl *FDecl,
4178                                                ArrayRef<Expr *> Args) {
4179   MemberExpr *ME = dyn_cast<MemberExpr>(Fn);
4180   DeclarationName FuncName = FDecl->getDeclName();
4181   SourceLocation NameLoc = ME ? ME->getMemberLoc() : Fn->getLocStart();
4182 
4183   if (TypoCorrection Corrected = S.CorrectTypo(
4184           DeclarationNameInfo(FuncName, NameLoc), Sema::LookupOrdinaryName,
4185           S.getScopeForContext(S.CurContext), nullptr,
4186           llvm::make_unique<FunctionCallCCC>(S, FuncName.getAsIdentifierInfo(),
4187                                              Args.size(), ME),
4188           Sema::CTK_ErrorRecovery)) {
4189     if (NamedDecl *ND = Corrected.getCorrectionDecl()) {
4190       if (Corrected.isOverloaded()) {
4191         OverloadCandidateSet OCS(NameLoc, OverloadCandidateSet::CSK_Normal);
4192         OverloadCandidateSet::iterator Best;
4193         for (TypoCorrection::decl_iterator CD = Corrected.begin(),
4194                                            CDEnd = Corrected.end();
4195              CD != CDEnd; ++CD) {
4196           if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*CD))
4197             S.AddOverloadCandidate(FD, DeclAccessPair::make(FD, AS_none), Args,
4198                                    OCS);
4199         }
4200         switch (OCS.BestViableFunction(S, NameLoc, Best)) {
4201         case OR_Success:
4202           ND = Best->Function;
4203           Corrected.setCorrectionDecl(ND);
4204           break;
4205         default:
4206           break;
4207         }
4208       }
4209       if (isa<ValueDecl>(ND) || isa<FunctionTemplateDecl>(ND)) {
4210         return Corrected;
4211       }
4212     }
4213   }
4214   return TypoCorrection();
4215 }
4216 
4217 /// ConvertArgumentsForCall - Converts the arguments specified in
4218 /// Args/NumArgs to the parameter types of the function FDecl with
4219 /// function prototype Proto. Call is the call expression itself, and
4220 /// Fn is the function expression. For a C++ member function, this
4221 /// routine does not attempt to convert the object argument. Returns
4222 /// true if the call is ill-formed.
4223 bool
ConvertArgumentsForCall(CallExpr * Call,Expr * Fn,FunctionDecl * FDecl,const FunctionProtoType * Proto,ArrayRef<Expr * > Args,SourceLocation RParenLoc,bool IsExecConfig)4224 Sema::ConvertArgumentsForCall(CallExpr *Call, Expr *Fn,
4225                               FunctionDecl *FDecl,
4226                               const FunctionProtoType *Proto,
4227                               ArrayRef<Expr *> Args,
4228                               SourceLocation RParenLoc,
4229                               bool IsExecConfig) {
4230   // Bail out early if calling a builtin with custom typechecking.
4231   // We don't need to do this in the
4232   if (FDecl)
4233     if (unsigned ID = FDecl->getBuiltinID())
4234       if (Context.BuiltinInfo.hasCustomTypechecking(ID))
4235         return false;
4236 
4237   // C99 6.5.2.2p7 - the arguments are implicitly converted, as if by
4238   // assignment, to the types of the corresponding parameter, ...
4239   unsigned NumParams = Proto->getNumParams();
4240   bool Invalid = false;
4241   unsigned MinArgs = FDecl ? FDecl->getMinRequiredArguments() : NumParams;
4242   unsigned FnKind = Fn->getType()->isBlockPointerType()
4243                        ? 1 /* block */
4244                        : (IsExecConfig ? 3 /* kernel function (exec config) */
4245                                        : 0 /* function */);
4246 
4247   // If too few arguments are available (and we don't have default
4248   // arguments for the remaining parameters), don't make the call.
4249   if (Args.size() < NumParams) {
4250     if (Args.size() < MinArgs) {
4251       TypoCorrection TC;
4252       if (FDecl && (TC = TryTypoCorrectionForCall(*this, Fn, FDecl, Args))) {
4253         unsigned diag_id =
4254             MinArgs == NumParams && !Proto->isVariadic()
4255                 ? diag::err_typecheck_call_too_few_args_suggest
4256                 : diag::err_typecheck_call_too_few_args_at_least_suggest;
4257         diagnoseTypo(TC, PDiag(diag_id) << FnKind << MinArgs
4258                                         << static_cast<unsigned>(Args.size())
4259                                         << TC.getCorrectionRange());
4260       } else if (MinArgs == 1 && FDecl && FDecl->getParamDecl(0)->getDeclName())
4261         Diag(RParenLoc,
4262              MinArgs == NumParams && !Proto->isVariadic()
4263                  ? diag::err_typecheck_call_too_few_args_one
4264                  : diag::err_typecheck_call_too_few_args_at_least_one)
4265             << FnKind << FDecl->getParamDecl(0) << Fn->getSourceRange();
4266       else
4267         Diag(RParenLoc, MinArgs == NumParams && !Proto->isVariadic()
4268                             ? diag::err_typecheck_call_too_few_args
4269                             : diag::err_typecheck_call_too_few_args_at_least)
4270             << FnKind << MinArgs << static_cast<unsigned>(Args.size())
4271             << Fn->getSourceRange();
4272 
4273       // Emit the location of the prototype.
4274       if (!TC && FDecl && !FDecl->getBuiltinID() && !IsExecConfig)
4275         Diag(FDecl->getLocStart(), diag::note_callee_decl)
4276           << FDecl;
4277 
4278       return true;
4279     }
4280     Call->setNumArgs(Context, NumParams);
4281   }
4282 
4283   // If too many are passed and not variadic, error on the extras and drop
4284   // them.
4285   if (Args.size() > NumParams) {
4286     if (!Proto->isVariadic()) {
4287       TypoCorrection TC;
4288       if (FDecl && (TC = TryTypoCorrectionForCall(*this, Fn, FDecl, Args))) {
4289         unsigned diag_id =
4290             MinArgs == NumParams && !Proto->isVariadic()
4291                 ? diag::err_typecheck_call_too_many_args_suggest
4292                 : diag::err_typecheck_call_too_many_args_at_most_suggest;
4293         diagnoseTypo(TC, PDiag(diag_id) << FnKind << NumParams
4294                                         << static_cast<unsigned>(Args.size())
4295                                         << TC.getCorrectionRange());
4296       } else if (NumParams == 1 && FDecl &&
4297                  FDecl->getParamDecl(0)->getDeclName())
4298         Diag(Args[NumParams]->getLocStart(),
4299              MinArgs == NumParams
4300                  ? diag::err_typecheck_call_too_many_args_one
4301                  : diag::err_typecheck_call_too_many_args_at_most_one)
4302             << FnKind << FDecl->getParamDecl(0)
4303             << static_cast<unsigned>(Args.size()) << Fn->getSourceRange()
4304             << SourceRange(Args[NumParams]->getLocStart(),
4305                            Args.back()->getLocEnd());
4306       else
4307         Diag(Args[NumParams]->getLocStart(),
4308              MinArgs == NumParams
4309                  ? diag::err_typecheck_call_too_many_args
4310                  : diag::err_typecheck_call_too_many_args_at_most)
4311             << FnKind << NumParams << static_cast<unsigned>(Args.size())
4312             << Fn->getSourceRange()
4313             << SourceRange(Args[NumParams]->getLocStart(),
4314                            Args.back()->getLocEnd());
4315 
4316       // Emit the location of the prototype.
4317       if (!TC && FDecl && !FDecl->getBuiltinID() && !IsExecConfig)
4318         Diag(FDecl->getLocStart(), diag::note_callee_decl)
4319           << FDecl;
4320 
4321       // This deletes the extra arguments.
4322       Call->setNumArgs(Context, NumParams);
4323       return true;
4324     }
4325   }
4326   SmallVector<Expr *, 8> AllArgs;
4327   VariadicCallType CallType = getVariadicCallType(FDecl, Proto, Fn);
4328 
4329   Invalid = GatherArgumentsForCall(Call->getLocStart(), FDecl,
4330                                    Proto, 0, Args, AllArgs, CallType);
4331   if (Invalid)
4332     return true;
4333   unsigned TotalNumArgs = AllArgs.size();
4334   for (unsigned i = 0; i < TotalNumArgs; ++i)
4335     Call->setArg(i, AllArgs[i]);
4336 
4337   return false;
4338 }
4339 
GatherArgumentsForCall(SourceLocation CallLoc,FunctionDecl * FDecl,const FunctionProtoType * Proto,unsigned FirstParam,ArrayRef<Expr * > Args,SmallVectorImpl<Expr * > & AllArgs,VariadicCallType CallType,bool AllowExplicit,bool IsListInitialization)4340 bool Sema::GatherArgumentsForCall(SourceLocation CallLoc, FunctionDecl *FDecl,
4341                                   const FunctionProtoType *Proto,
4342                                   unsigned FirstParam, ArrayRef<Expr *> Args,
4343                                   SmallVectorImpl<Expr *> &AllArgs,
4344                                   VariadicCallType CallType, bool AllowExplicit,
4345                                   bool IsListInitialization) {
4346   unsigned NumParams = Proto->getNumParams();
4347   bool Invalid = false;
4348   unsigned ArgIx = 0;
4349   // Continue to check argument types (even if we have too few/many args).
4350   for (unsigned i = FirstParam; i < NumParams; i++) {
4351     QualType ProtoArgType = Proto->getParamType(i);
4352 
4353     Expr *Arg;
4354     ParmVarDecl *Param = FDecl ? FDecl->getParamDecl(i) : nullptr;
4355     if (ArgIx < Args.size()) {
4356       Arg = Args[ArgIx++];
4357 
4358       if (RequireCompleteType(Arg->getLocStart(),
4359                               ProtoArgType,
4360                               diag::err_call_incomplete_argument, Arg))
4361         return true;
4362 
4363       // Strip the unbridged-cast placeholder expression off, if applicable.
4364       bool CFAudited = false;
4365       if (Arg->getType() == Context.ARCUnbridgedCastTy &&
4366           FDecl && FDecl->hasAttr<CFAuditedTransferAttr>() &&
4367           (!Param || !Param->hasAttr<CFConsumedAttr>()))
4368         Arg = stripARCUnbridgedCast(Arg);
4369       else if (getLangOpts().ObjCAutoRefCount &&
4370                FDecl && FDecl->hasAttr<CFAuditedTransferAttr>() &&
4371                (!Param || !Param->hasAttr<CFConsumedAttr>()))
4372         CFAudited = true;
4373 
4374       InitializedEntity Entity =
4375           Param ? InitializedEntity::InitializeParameter(Context, Param,
4376                                                          ProtoArgType)
4377                 : InitializedEntity::InitializeParameter(
4378                       Context, ProtoArgType, Proto->isParamConsumed(i));
4379 
4380       // Remember that parameter belongs to a CF audited API.
4381       if (CFAudited)
4382         Entity.setParameterCFAudited();
4383 
4384       ExprResult ArgE = PerformCopyInitialization(
4385           Entity, SourceLocation(), Arg, IsListInitialization, AllowExplicit);
4386       if (ArgE.isInvalid())
4387         return true;
4388 
4389       Arg = ArgE.getAs<Expr>();
4390     } else {
4391       assert(Param && "can't use default arguments without a known callee");
4392 
4393       ExprResult ArgExpr =
4394         BuildCXXDefaultArgExpr(CallLoc, FDecl, Param);
4395       if (ArgExpr.isInvalid())
4396         return true;
4397 
4398       Arg = ArgExpr.getAs<Expr>();
4399     }
4400 
4401     // Check for array bounds violations for each argument to the call. This
4402     // check only triggers warnings when the argument isn't a more complex Expr
4403     // with its own checking, such as a BinaryOperator.
4404     CheckArrayAccess(Arg);
4405 
4406     // Check for violations of C99 static array rules (C99 6.7.5.3p7).
4407     CheckStaticArrayArgument(CallLoc, Param, Arg);
4408 
4409     AllArgs.push_back(Arg);
4410   }
4411 
4412   // If this is a variadic call, handle args passed through "...".
4413   if (CallType != VariadicDoesNotApply) {
4414     // Assume that extern "C" functions with variadic arguments that
4415     // return __unknown_anytype aren't *really* variadic.
4416     if (Proto->getReturnType() == Context.UnknownAnyTy && FDecl &&
4417         FDecl->isExternC()) {
4418       for (unsigned i = ArgIx, e = Args.size(); i != e; ++i) {
4419         QualType paramType; // ignored
4420         ExprResult arg = checkUnknownAnyArg(CallLoc, Args[i], paramType);
4421         Invalid |= arg.isInvalid();
4422         AllArgs.push_back(arg.get());
4423       }
4424 
4425     // Otherwise do argument promotion, (C99 6.5.2.2p7).
4426     } else {
4427       for (unsigned i = ArgIx, e = Args.size(); i != e; ++i) {
4428         ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], CallType,
4429                                                           FDecl);
4430         Invalid |= Arg.isInvalid();
4431         AllArgs.push_back(Arg.get());
4432       }
4433     }
4434 
4435     // Check for array bounds violations.
4436     for (unsigned i = ArgIx, e = Args.size(); i != e; ++i)
4437       CheckArrayAccess(Args[i]);
4438   }
4439   return Invalid;
4440 }
4441 
DiagnoseCalleeStaticArrayParam(Sema & S,ParmVarDecl * PVD)4442 static void DiagnoseCalleeStaticArrayParam(Sema &S, ParmVarDecl *PVD) {
4443   TypeLoc TL = PVD->getTypeSourceInfo()->getTypeLoc();
4444   if (DecayedTypeLoc DTL = TL.getAs<DecayedTypeLoc>())
4445     TL = DTL.getOriginalLoc();
4446   if (ArrayTypeLoc ATL = TL.getAs<ArrayTypeLoc>())
4447     S.Diag(PVD->getLocation(), diag::note_callee_static_array)
4448       << ATL.getLocalSourceRange();
4449 }
4450 
4451 /// CheckStaticArrayArgument - If the given argument corresponds to a static
4452 /// array parameter, check that it is non-null, and that if it is formed by
4453 /// array-to-pointer decay, the underlying array is sufficiently large.
4454 ///
4455 /// C99 6.7.5.3p7: If the keyword static also appears within the [ and ] of the
4456 /// array type derivation, then for each call to the function, the value of the
4457 /// corresponding actual argument shall provide access to the first element of
4458 /// an array with at least as many elements as specified by the size expression.
4459 void
CheckStaticArrayArgument(SourceLocation CallLoc,ParmVarDecl * Param,const Expr * ArgExpr)4460 Sema::CheckStaticArrayArgument(SourceLocation CallLoc,
4461                                ParmVarDecl *Param,
4462                                const Expr *ArgExpr) {
4463   // Static array parameters are not supported in C++.
4464   if (!Param || getLangOpts().CPlusPlus)
4465     return;
4466 
4467   QualType OrigTy = Param->getOriginalType();
4468 
4469   const ArrayType *AT = Context.getAsArrayType(OrigTy);
4470   if (!AT || AT->getSizeModifier() != ArrayType::Static)
4471     return;
4472 
4473   if (ArgExpr->isNullPointerConstant(Context,
4474                                      Expr::NPC_NeverValueDependent)) {
4475     Diag(CallLoc, diag::warn_null_arg) << ArgExpr->getSourceRange();
4476     DiagnoseCalleeStaticArrayParam(*this, Param);
4477     return;
4478   }
4479 
4480   const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(AT);
4481   if (!CAT)
4482     return;
4483 
4484   const ConstantArrayType *ArgCAT =
4485     Context.getAsConstantArrayType(ArgExpr->IgnoreParenImpCasts()->getType());
4486   if (!ArgCAT)
4487     return;
4488 
4489   if (ArgCAT->getSize().ult(CAT->getSize())) {
4490     Diag(CallLoc, diag::warn_static_array_too_small)
4491       << ArgExpr->getSourceRange()
4492       << (unsigned) ArgCAT->getSize().getZExtValue()
4493       << (unsigned) CAT->getSize().getZExtValue();
4494     DiagnoseCalleeStaticArrayParam(*this, Param);
4495   }
4496 }
4497 
4498 /// Given a function expression of unknown-any type, try to rebuild it
4499 /// to have a function type.
4500 static ExprResult rebuildUnknownAnyFunction(Sema &S, Expr *fn);
4501 
4502 /// Is the given type a placeholder that we need to lower out
4503 /// immediately during argument processing?
isPlaceholderToRemoveAsArg(QualType type)4504 static bool isPlaceholderToRemoveAsArg(QualType type) {
4505   // Placeholders are never sugared.
4506   const BuiltinType *placeholder = dyn_cast<BuiltinType>(type);
4507   if (!placeholder) return false;
4508 
4509   switch (placeholder->getKind()) {
4510   // Ignore all the non-placeholder types.
4511 #define PLACEHOLDER_TYPE(ID, SINGLETON_ID)
4512 #define BUILTIN_TYPE(ID, SINGLETON_ID) case BuiltinType::ID:
4513 #include "clang/AST/BuiltinTypes.def"
4514     return false;
4515 
4516   // We cannot lower out overload sets; they might validly be resolved
4517   // by the call machinery.
4518   case BuiltinType::Overload:
4519     return false;
4520 
4521   // Unbridged casts in ARC can be handled in some call positions and
4522   // should be left in place.
4523   case BuiltinType::ARCUnbridgedCast:
4524     return false;
4525 
4526   // Pseudo-objects should be converted as soon as possible.
4527   case BuiltinType::PseudoObject:
4528     return true;
4529 
4530   // The debugger mode could theoretically but currently does not try
4531   // to resolve unknown-typed arguments based on known parameter types.
4532   case BuiltinType::UnknownAny:
4533     return true;
4534 
4535   // These are always invalid as call arguments and should be reported.
4536   case BuiltinType::BoundMember:
4537   case BuiltinType::BuiltinFn:
4538     return true;
4539   }
4540   llvm_unreachable("bad builtin type kind");
4541 }
4542 
4543 /// Check an argument list for placeholders that we won't try to
4544 /// handle later.
checkArgsForPlaceholders(Sema & S,MultiExprArg args)4545 static bool checkArgsForPlaceholders(Sema &S, MultiExprArg args) {
4546   // Apply this processing to all the arguments at once instead of
4547   // dying at the first failure.
4548   bool hasInvalid = false;
4549   for (size_t i = 0, e = args.size(); i != e; i++) {
4550     if (isPlaceholderToRemoveAsArg(args[i]->getType())) {
4551       ExprResult result = S.CheckPlaceholderExpr(args[i]);
4552       if (result.isInvalid()) hasInvalid = true;
4553       else args[i] = result.get();
4554     } else if (hasInvalid) {
4555       (void)S.CorrectDelayedTyposInExpr(args[i]);
4556     }
4557   }
4558   return hasInvalid;
4559 }
4560 
4561 /// ActOnCallExpr - Handle a call to Fn with the specified array of arguments.
4562 /// This provides the location of the left/right parens and a list of comma
4563 /// locations.
4564 ExprResult
ActOnCallExpr(Scope * S,Expr * Fn,SourceLocation LParenLoc,MultiExprArg ArgExprs,SourceLocation RParenLoc,Expr * ExecConfig,bool IsExecConfig)4565 Sema::ActOnCallExpr(Scope *S, Expr *Fn, SourceLocation LParenLoc,
4566                     MultiExprArg ArgExprs, SourceLocation RParenLoc,
4567                     Expr *ExecConfig, bool IsExecConfig) {
4568   // Since this might be a postfix expression, get rid of ParenListExprs.
4569   ExprResult Result = MaybeConvertParenListExprToParenExpr(S, Fn);
4570   if (Result.isInvalid()) return ExprError();
4571   Fn = Result.get();
4572 
4573   if (checkArgsForPlaceholders(*this, ArgExprs))
4574     return ExprError();
4575 
4576   if (getLangOpts().CPlusPlus) {
4577     // If this is a pseudo-destructor expression, build the call immediately.
4578     if (isa<CXXPseudoDestructorExpr>(Fn)) {
4579       if (!ArgExprs.empty()) {
4580         // Pseudo-destructor calls should not have any arguments.
4581         Diag(Fn->getLocStart(), diag::err_pseudo_dtor_call_with_args)
4582           << FixItHint::CreateRemoval(
4583                                     SourceRange(ArgExprs[0]->getLocStart(),
4584                                                 ArgExprs.back()->getLocEnd()));
4585       }
4586 
4587       return new (Context)
4588           CallExpr(Context, Fn, None, Context.VoidTy, VK_RValue, RParenLoc);
4589     }
4590     if (Fn->getType() == Context.PseudoObjectTy) {
4591       ExprResult result = CheckPlaceholderExpr(Fn);
4592       if (result.isInvalid()) return ExprError();
4593       Fn = result.get();
4594     }
4595 
4596     // Determine whether this is a dependent call inside a C++ template,
4597     // in which case we won't do any semantic analysis now.
4598     // FIXME: Will need to cache the results of name lookup (including ADL) in
4599     // Fn.
4600     bool Dependent = false;
4601     if (Fn->isTypeDependent())
4602       Dependent = true;
4603     else if (Expr::hasAnyTypeDependentArguments(ArgExprs))
4604       Dependent = true;
4605 
4606     if (Dependent) {
4607       if (ExecConfig) {
4608         return new (Context) CUDAKernelCallExpr(
4609             Context, Fn, cast<CallExpr>(ExecConfig), ArgExprs,
4610             Context.DependentTy, VK_RValue, RParenLoc);
4611       } else {
4612         return new (Context) CallExpr(
4613             Context, Fn, ArgExprs, Context.DependentTy, VK_RValue, RParenLoc);
4614       }
4615     }
4616 
4617     // Determine whether this is a call to an object (C++ [over.call.object]).
4618     if (Fn->getType()->isRecordType())
4619       return BuildCallToObjectOfClassType(S, Fn, LParenLoc, ArgExprs,
4620                                           RParenLoc);
4621 
4622     if (Fn->getType() == Context.UnknownAnyTy) {
4623       ExprResult result = rebuildUnknownAnyFunction(*this, Fn);
4624       if (result.isInvalid()) return ExprError();
4625       Fn = result.get();
4626     }
4627 
4628     if (Fn->getType() == Context.BoundMemberTy) {
4629       return BuildCallToMemberFunction(S, Fn, LParenLoc, ArgExprs, RParenLoc);
4630     }
4631   }
4632 
4633   // Check for overloaded calls.  This can happen even in C due to extensions.
4634   if (Fn->getType() == Context.OverloadTy) {
4635     OverloadExpr::FindResult find = OverloadExpr::find(Fn);
4636 
4637     // We aren't supposed to apply this logic for if there's an '&' involved.
4638     if (!find.HasFormOfMemberPointer) {
4639       OverloadExpr *ovl = find.Expression;
4640       if (isa<UnresolvedLookupExpr>(ovl)) {
4641         UnresolvedLookupExpr *ULE = cast<UnresolvedLookupExpr>(ovl);
4642         return BuildOverloadedCallExpr(S, Fn, ULE, LParenLoc, ArgExprs,
4643                                        RParenLoc, ExecConfig);
4644       } else {
4645         return BuildCallToMemberFunction(S, Fn, LParenLoc, ArgExprs,
4646                                          RParenLoc);
4647       }
4648     }
4649   }
4650 
4651   // If we're directly calling a function, get the appropriate declaration.
4652   if (Fn->getType() == Context.UnknownAnyTy) {
4653     ExprResult result = rebuildUnknownAnyFunction(*this, Fn);
4654     if (result.isInvalid()) return ExprError();
4655     Fn = result.get();
4656   }
4657 
4658   Expr *NakedFn = Fn->IgnoreParens();
4659 
4660   NamedDecl *NDecl = nullptr;
4661   if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(NakedFn))
4662     if (UnOp->getOpcode() == UO_AddrOf)
4663       NakedFn = UnOp->getSubExpr()->IgnoreParens();
4664 
4665   if (isa<DeclRefExpr>(NakedFn))
4666     NDecl = cast<DeclRefExpr>(NakedFn)->getDecl();
4667   else if (isa<MemberExpr>(NakedFn))
4668     NDecl = cast<MemberExpr>(NakedFn)->getMemberDecl();
4669 
4670   if (FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(NDecl)) {
4671     if (FD->hasAttr<EnableIfAttr>()) {
4672       if (const EnableIfAttr *Attr = CheckEnableIf(FD, ArgExprs, true)) {
4673         Diag(Fn->getLocStart(),
4674              isa<CXXMethodDecl>(FD) ?
4675                  diag::err_ovl_no_viable_member_function_in_call :
4676                  diag::err_ovl_no_viable_function_in_call)
4677           << FD << FD->getSourceRange();
4678         Diag(FD->getLocation(),
4679              diag::note_ovl_candidate_disabled_by_enable_if_attr)
4680             << Attr->getCond()->getSourceRange() << Attr->getMessage();
4681       }
4682     }
4683   }
4684 
4685   return BuildResolvedCallExpr(Fn, NDecl, LParenLoc, ArgExprs, RParenLoc,
4686                                ExecConfig, IsExecConfig);
4687 }
4688 
4689 /// ActOnAsTypeExpr - create a new asType (bitcast) from the arguments.
4690 ///
4691 /// __builtin_astype( value, dst type )
4692 ///
ActOnAsTypeExpr(Expr * E,ParsedType ParsedDestTy,SourceLocation BuiltinLoc,SourceLocation RParenLoc)4693 ExprResult Sema::ActOnAsTypeExpr(Expr *E, ParsedType ParsedDestTy,
4694                                  SourceLocation BuiltinLoc,
4695                                  SourceLocation RParenLoc) {
4696   ExprValueKind VK = VK_RValue;
4697   ExprObjectKind OK = OK_Ordinary;
4698   QualType DstTy = GetTypeFromParser(ParsedDestTy);
4699   QualType SrcTy = E->getType();
4700   if (Context.getTypeSize(DstTy) != Context.getTypeSize(SrcTy))
4701     return ExprError(Diag(BuiltinLoc,
4702                           diag::err_invalid_astype_of_different_size)
4703                      << DstTy
4704                      << SrcTy
4705                      << E->getSourceRange());
4706   return new (Context) AsTypeExpr(E, DstTy, VK, OK, BuiltinLoc, RParenLoc);
4707 }
4708 
4709 /// ActOnConvertVectorExpr - create a new convert-vector expression from the
4710 /// provided arguments.
4711 ///
4712 /// __builtin_convertvector( value, dst type )
4713 ///
ActOnConvertVectorExpr(Expr * E,ParsedType ParsedDestTy,SourceLocation BuiltinLoc,SourceLocation RParenLoc)4714 ExprResult Sema::ActOnConvertVectorExpr(Expr *E, ParsedType ParsedDestTy,
4715                                         SourceLocation BuiltinLoc,
4716                                         SourceLocation RParenLoc) {
4717   TypeSourceInfo *TInfo;
4718   GetTypeFromParser(ParsedDestTy, &TInfo);
4719   return SemaConvertVectorExpr(E, TInfo, BuiltinLoc, RParenLoc);
4720 }
4721 
4722 /// BuildResolvedCallExpr - Build a call to a resolved expression,
4723 /// i.e. an expression not of \p OverloadTy.  The expression should
4724 /// unary-convert to an expression of function-pointer or
4725 /// block-pointer type.
4726 ///
4727 /// \param NDecl the declaration being called, if available
4728 ExprResult
BuildResolvedCallExpr(Expr * Fn,NamedDecl * NDecl,SourceLocation LParenLoc,ArrayRef<Expr * > Args,SourceLocation RParenLoc,Expr * Config,bool IsExecConfig)4729 Sema::BuildResolvedCallExpr(Expr *Fn, NamedDecl *NDecl,
4730                             SourceLocation LParenLoc,
4731                             ArrayRef<Expr *> Args,
4732                             SourceLocation RParenLoc,
4733                             Expr *Config, bool IsExecConfig) {
4734   FunctionDecl *FDecl = dyn_cast_or_null<FunctionDecl>(NDecl);
4735   unsigned BuiltinID = (FDecl ? FDecl->getBuiltinID() : 0);
4736 
4737   // Promote the function operand.
4738   // We special-case function promotion here because we only allow promoting
4739   // builtin functions to function pointers in the callee of a call.
4740   ExprResult Result;
4741   if (BuiltinID &&
4742       Fn->getType()->isSpecificBuiltinType(BuiltinType::BuiltinFn)) {
4743     Result = ImpCastExprToType(Fn, Context.getPointerType(FDecl->getType()),
4744                                CK_BuiltinFnToFnPtr).get();
4745   } else {
4746     Result = CallExprUnaryConversions(Fn);
4747   }
4748   if (Result.isInvalid())
4749     return ExprError();
4750   Fn = Result.get();
4751 
4752   // Make the call expr early, before semantic checks.  This guarantees cleanup
4753   // of arguments and function on error.
4754   CallExpr *TheCall;
4755   if (Config)
4756     TheCall = new (Context) CUDAKernelCallExpr(Context, Fn,
4757                                                cast<CallExpr>(Config), Args,
4758                                                Context.BoolTy, VK_RValue,
4759                                                RParenLoc);
4760   else
4761     TheCall = new (Context) CallExpr(Context, Fn, Args, Context.BoolTy,
4762                                      VK_RValue, RParenLoc);
4763 
4764   // Bail out early if calling a builtin with custom typechecking.
4765   if (BuiltinID && Context.BuiltinInfo.hasCustomTypechecking(BuiltinID))
4766     return CheckBuiltinFunctionCall(FDecl, BuiltinID, TheCall);
4767 
4768  retry:
4769   const FunctionType *FuncT;
4770   if (const PointerType *PT = Fn->getType()->getAs<PointerType>()) {
4771     // C99 6.5.2.2p1 - "The expression that denotes the called function shall
4772     // have type pointer to function".
4773     FuncT = PT->getPointeeType()->getAs<FunctionType>();
4774     if (!FuncT)
4775       return ExprError(Diag(LParenLoc, diag::err_typecheck_call_not_function)
4776                          << Fn->getType() << Fn->getSourceRange());
4777   } else if (const BlockPointerType *BPT =
4778                Fn->getType()->getAs<BlockPointerType>()) {
4779     FuncT = BPT->getPointeeType()->castAs<FunctionType>();
4780   } else {
4781     // Handle calls to expressions of unknown-any type.
4782     if (Fn->getType() == Context.UnknownAnyTy) {
4783       ExprResult rewrite = rebuildUnknownAnyFunction(*this, Fn);
4784       if (rewrite.isInvalid()) return ExprError();
4785       Fn = rewrite.get();
4786       TheCall->setCallee(Fn);
4787       goto retry;
4788     }
4789 
4790     return ExprError(Diag(LParenLoc, diag::err_typecheck_call_not_function)
4791       << Fn->getType() << Fn->getSourceRange());
4792   }
4793 
4794   if (getLangOpts().CUDA) {
4795     if (Config) {
4796       // CUDA: Kernel calls must be to global functions
4797       if (FDecl && !FDecl->hasAttr<CUDAGlobalAttr>())
4798         return ExprError(Diag(LParenLoc,diag::err_kern_call_not_global_function)
4799             << FDecl->getName() << Fn->getSourceRange());
4800 
4801       // CUDA: Kernel function must have 'void' return type
4802       if (!FuncT->getReturnType()->isVoidType())
4803         return ExprError(Diag(LParenLoc, diag::err_kern_type_not_void_return)
4804             << Fn->getType() << Fn->getSourceRange());
4805     } else {
4806       // CUDA: Calls to global functions must be configured
4807       if (FDecl && FDecl->hasAttr<CUDAGlobalAttr>())
4808         return ExprError(Diag(LParenLoc, diag::err_global_call_not_config)
4809             << FDecl->getName() << Fn->getSourceRange());
4810     }
4811   }
4812 
4813   // Check for a valid return type
4814   if (CheckCallReturnType(FuncT->getReturnType(), Fn->getLocStart(), TheCall,
4815                           FDecl))
4816     return ExprError();
4817 
4818   // We know the result type of the call, set it.
4819   TheCall->setType(FuncT->getCallResultType(Context));
4820   TheCall->setValueKind(Expr::getValueKindForType(FuncT->getReturnType()));
4821 
4822   const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FuncT);
4823   if (Proto) {
4824     if (ConvertArgumentsForCall(TheCall, Fn, FDecl, Proto, Args, RParenLoc,
4825                                 IsExecConfig))
4826       return ExprError();
4827   } else {
4828     assert(isa<FunctionNoProtoType>(FuncT) && "Unknown FunctionType!");
4829 
4830     if (FDecl) {
4831       // Check if we have too few/too many template arguments, based
4832       // on our knowledge of the function definition.
4833       const FunctionDecl *Def = nullptr;
4834       if (FDecl->hasBody(Def) && Args.size() != Def->param_size()) {
4835         Proto = Def->getType()->getAs<FunctionProtoType>();
4836        if (!Proto || !(Proto->isVariadic() && Args.size() >= Def->param_size()))
4837           Diag(RParenLoc, diag::warn_call_wrong_number_of_arguments)
4838           << (Args.size() > Def->param_size()) << FDecl << Fn->getSourceRange();
4839       }
4840 
4841       // If the function we're calling isn't a function prototype, but we have
4842       // a function prototype from a prior declaratiom, use that prototype.
4843       if (!FDecl->hasPrototype())
4844         Proto = FDecl->getType()->getAs<FunctionProtoType>();
4845     }
4846 
4847     // Promote the arguments (C99 6.5.2.2p6).
4848     for (unsigned i = 0, e = Args.size(); i != e; i++) {
4849       Expr *Arg = Args[i];
4850 
4851       if (Proto && i < Proto->getNumParams()) {
4852         InitializedEntity Entity = InitializedEntity::InitializeParameter(
4853             Context, Proto->getParamType(i), Proto->isParamConsumed(i));
4854         ExprResult ArgE =
4855             PerformCopyInitialization(Entity, SourceLocation(), Arg);
4856         if (ArgE.isInvalid())
4857           return true;
4858 
4859         Arg = ArgE.getAs<Expr>();
4860 
4861       } else {
4862         ExprResult ArgE = DefaultArgumentPromotion(Arg);
4863 
4864         if (ArgE.isInvalid())
4865           return true;
4866 
4867         Arg = ArgE.getAs<Expr>();
4868       }
4869 
4870       if (RequireCompleteType(Arg->getLocStart(),
4871                               Arg->getType(),
4872                               diag::err_call_incomplete_argument, Arg))
4873         return ExprError();
4874 
4875       TheCall->setArg(i, Arg);
4876     }
4877   }
4878 
4879   if (CXXMethodDecl *Method = dyn_cast_or_null<CXXMethodDecl>(FDecl))
4880     if (!Method->isStatic())
4881       return ExprError(Diag(LParenLoc, diag::err_member_call_without_object)
4882         << Fn->getSourceRange());
4883 
4884   // Check for sentinels
4885   if (NDecl)
4886     DiagnoseSentinelCalls(NDecl, LParenLoc, Args);
4887 
4888   // Do special checking on direct calls to functions.
4889   if (FDecl) {
4890     if (CheckFunctionCall(FDecl, TheCall, Proto))
4891       return ExprError();
4892 
4893     if (BuiltinID)
4894       return CheckBuiltinFunctionCall(FDecl, BuiltinID, TheCall);
4895   } else if (NDecl) {
4896     if (CheckPointerCall(NDecl, TheCall, Proto))
4897       return ExprError();
4898   } else {
4899     if (CheckOtherCall(TheCall, Proto))
4900       return ExprError();
4901   }
4902 
4903   return MaybeBindToTemporary(TheCall);
4904 }
4905 
4906 ExprResult
ActOnCompoundLiteral(SourceLocation LParenLoc,ParsedType Ty,SourceLocation RParenLoc,Expr * InitExpr)4907 Sema::ActOnCompoundLiteral(SourceLocation LParenLoc, ParsedType Ty,
4908                            SourceLocation RParenLoc, Expr *InitExpr) {
4909   assert(Ty && "ActOnCompoundLiteral(): missing type");
4910   // FIXME: put back this assert when initializers are worked out.
4911   //assert((InitExpr != 0) && "ActOnCompoundLiteral(): missing expression");
4912 
4913   TypeSourceInfo *TInfo;
4914   QualType literalType = GetTypeFromParser(Ty, &TInfo);
4915   if (!TInfo)
4916     TInfo = Context.getTrivialTypeSourceInfo(literalType);
4917 
4918   return BuildCompoundLiteralExpr(LParenLoc, TInfo, RParenLoc, InitExpr);
4919 }
4920 
4921 ExprResult
BuildCompoundLiteralExpr(SourceLocation LParenLoc,TypeSourceInfo * TInfo,SourceLocation RParenLoc,Expr * LiteralExpr)4922 Sema::BuildCompoundLiteralExpr(SourceLocation LParenLoc, TypeSourceInfo *TInfo,
4923                                SourceLocation RParenLoc, Expr *LiteralExpr) {
4924   QualType literalType = TInfo->getType();
4925 
4926   if (literalType->isArrayType()) {
4927     if (RequireCompleteType(LParenLoc, Context.getBaseElementType(literalType),
4928           diag::err_illegal_decl_array_incomplete_type,
4929           SourceRange(LParenLoc,
4930                       LiteralExpr->getSourceRange().getEnd())))
4931       return ExprError();
4932     if (literalType->isVariableArrayType())
4933       return ExprError(Diag(LParenLoc, diag::err_variable_object_no_init)
4934         << SourceRange(LParenLoc, LiteralExpr->getSourceRange().getEnd()));
4935   } else if (!literalType->isDependentType() &&
4936              RequireCompleteType(LParenLoc, literalType,
4937                diag::err_typecheck_decl_incomplete_type,
4938                SourceRange(LParenLoc, LiteralExpr->getSourceRange().getEnd())))
4939     return ExprError();
4940 
4941   InitializedEntity Entity
4942     = InitializedEntity::InitializeCompoundLiteralInit(TInfo);
4943   InitializationKind Kind
4944     = InitializationKind::CreateCStyleCast(LParenLoc,
4945                                            SourceRange(LParenLoc, RParenLoc),
4946                                            /*InitList=*/true);
4947   InitializationSequence InitSeq(*this, Entity, Kind, LiteralExpr);
4948   ExprResult Result = InitSeq.Perform(*this, Entity, Kind, LiteralExpr,
4949                                       &literalType);
4950   if (Result.isInvalid())
4951     return ExprError();
4952   LiteralExpr = Result.get();
4953 
4954   bool isFileScope = getCurFunctionOrMethodDecl() == nullptr;
4955   if (isFileScope &&
4956       !LiteralExpr->isTypeDependent() &&
4957       !LiteralExpr->isValueDependent() &&
4958       !literalType->isDependentType()) { // 6.5.2.5p3
4959     if (CheckForConstantInitializer(LiteralExpr, literalType))
4960       return ExprError();
4961   }
4962 
4963   // In C, compound literals are l-values for some reason.
4964   ExprValueKind VK = getLangOpts().CPlusPlus ? VK_RValue : VK_LValue;
4965 
4966   return MaybeBindToTemporary(
4967            new (Context) CompoundLiteralExpr(LParenLoc, TInfo, literalType,
4968                                              VK, LiteralExpr, isFileScope));
4969 }
4970 
4971 ExprResult
ActOnInitList(SourceLocation LBraceLoc,MultiExprArg InitArgList,SourceLocation RBraceLoc)4972 Sema::ActOnInitList(SourceLocation LBraceLoc, MultiExprArg InitArgList,
4973                     SourceLocation RBraceLoc) {
4974   // Immediately handle non-overload placeholders.  Overloads can be
4975   // resolved contextually, but everything else here can't.
4976   for (unsigned I = 0, E = InitArgList.size(); I != E; ++I) {
4977     if (InitArgList[I]->getType()->isNonOverloadPlaceholderType()) {
4978       ExprResult result = CheckPlaceholderExpr(InitArgList[I]);
4979 
4980       // Ignore failures; dropping the entire initializer list because
4981       // of one failure would be terrible for indexing/etc.
4982       if (result.isInvalid()) continue;
4983 
4984       InitArgList[I] = result.get();
4985     }
4986   }
4987 
4988   // Semantic analysis for initializers is done by ActOnDeclarator() and
4989   // CheckInitializer() - it requires knowledge of the object being intialized.
4990 
4991   InitListExpr *E = new (Context) InitListExpr(Context, LBraceLoc, InitArgList,
4992                                                RBraceLoc);
4993   E->setType(Context.VoidTy); // FIXME: just a place holder for now.
4994   return E;
4995 }
4996 
4997 /// Do an explicit extend of the given block pointer if we're in ARC.
maybeExtendBlockObject(Sema & S,ExprResult & E)4998 static void maybeExtendBlockObject(Sema &S, ExprResult &E) {
4999   assert(E.get()->getType()->isBlockPointerType());
5000   assert(E.get()->isRValue());
5001 
5002   // Only do this in an r-value context.
5003   if (!S.getLangOpts().ObjCAutoRefCount) return;
5004 
5005   E = ImplicitCastExpr::Create(S.Context, E.get()->getType(),
5006                                CK_ARCExtendBlockObject, E.get(),
5007                                /*base path*/ nullptr, VK_RValue);
5008   S.ExprNeedsCleanups = true;
5009 }
5010 
5011 /// Prepare a conversion of the given expression to an ObjC object
5012 /// pointer type.
PrepareCastToObjCObjectPointer(ExprResult & E)5013 CastKind Sema::PrepareCastToObjCObjectPointer(ExprResult &E) {
5014   QualType type = E.get()->getType();
5015   if (type->isObjCObjectPointerType()) {
5016     return CK_BitCast;
5017   } else if (type->isBlockPointerType()) {
5018     maybeExtendBlockObject(*this, E);
5019     return CK_BlockPointerToObjCPointerCast;
5020   } else {
5021     assert(type->isPointerType());
5022     return CK_CPointerToObjCPointerCast;
5023   }
5024 }
5025 
5026 /// Prepares for a scalar cast, performing all the necessary stages
5027 /// except the final cast and returning the kind required.
PrepareScalarCast(ExprResult & Src,QualType DestTy)5028 CastKind Sema::PrepareScalarCast(ExprResult &Src, QualType DestTy) {
5029   // Both Src and Dest are scalar types, i.e. arithmetic or pointer.
5030   // Also, callers should have filtered out the invalid cases with
5031   // pointers.  Everything else should be possible.
5032 
5033   QualType SrcTy = Src.get()->getType();
5034   if (Context.hasSameUnqualifiedType(SrcTy, DestTy))
5035     return CK_NoOp;
5036 
5037   switch (Type::ScalarTypeKind SrcKind = SrcTy->getScalarTypeKind()) {
5038   case Type::STK_MemberPointer:
5039     llvm_unreachable("member pointer type in C");
5040 
5041   case Type::STK_CPointer:
5042   case Type::STK_BlockPointer:
5043   case Type::STK_ObjCObjectPointer:
5044     switch (DestTy->getScalarTypeKind()) {
5045     case Type::STK_CPointer: {
5046       unsigned SrcAS = SrcTy->getPointeeType().getAddressSpace();
5047       unsigned DestAS = DestTy->getPointeeType().getAddressSpace();
5048       if (SrcAS != DestAS)
5049         return CK_AddressSpaceConversion;
5050       return CK_BitCast;
5051     }
5052     case Type::STK_BlockPointer:
5053       return (SrcKind == Type::STK_BlockPointer
5054                 ? CK_BitCast : CK_AnyPointerToBlockPointerCast);
5055     case Type::STK_ObjCObjectPointer:
5056       if (SrcKind == Type::STK_ObjCObjectPointer)
5057         return CK_BitCast;
5058       if (SrcKind == Type::STK_CPointer)
5059         return CK_CPointerToObjCPointerCast;
5060       maybeExtendBlockObject(*this, Src);
5061       return CK_BlockPointerToObjCPointerCast;
5062     case Type::STK_Bool:
5063       return CK_PointerToBoolean;
5064     case Type::STK_Integral:
5065       return CK_PointerToIntegral;
5066     case Type::STK_Floating:
5067     case Type::STK_FloatingComplex:
5068     case Type::STK_IntegralComplex:
5069     case Type::STK_MemberPointer:
5070       llvm_unreachable("illegal cast from pointer");
5071     }
5072     llvm_unreachable("Should have returned before this");
5073 
5074   case Type::STK_Bool: // casting from bool is like casting from an integer
5075   case Type::STK_Integral:
5076     switch (DestTy->getScalarTypeKind()) {
5077     case Type::STK_CPointer:
5078     case Type::STK_ObjCObjectPointer:
5079     case Type::STK_BlockPointer:
5080       if (Src.get()->isNullPointerConstant(Context,
5081                                            Expr::NPC_ValueDependentIsNull))
5082         return CK_NullToPointer;
5083       return CK_IntegralToPointer;
5084     case Type::STK_Bool:
5085       return CK_IntegralToBoolean;
5086     case Type::STK_Integral:
5087       return CK_IntegralCast;
5088     case Type::STK_Floating:
5089       return CK_IntegralToFloating;
5090     case Type::STK_IntegralComplex:
5091       Src = ImpCastExprToType(Src.get(),
5092                               DestTy->castAs<ComplexType>()->getElementType(),
5093                               CK_IntegralCast);
5094       return CK_IntegralRealToComplex;
5095     case Type::STK_FloatingComplex:
5096       Src = ImpCastExprToType(Src.get(),
5097                               DestTy->castAs<ComplexType>()->getElementType(),
5098                               CK_IntegralToFloating);
5099       return CK_FloatingRealToComplex;
5100     case Type::STK_MemberPointer:
5101       llvm_unreachable("member pointer type in C");
5102     }
5103     llvm_unreachable("Should have returned before this");
5104 
5105   case Type::STK_Floating:
5106     switch (DestTy->getScalarTypeKind()) {
5107     case Type::STK_Floating:
5108       return CK_FloatingCast;
5109     case Type::STK_Bool:
5110       return CK_FloatingToBoolean;
5111     case Type::STK_Integral:
5112       return CK_FloatingToIntegral;
5113     case Type::STK_FloatingComplex:
5114       Src = ImpCastExprToType(Src.get(),
5115                               DestTy->castAs<ComplexType>()->getElementType(),
5116                               CK_FloatingCast);
5117       return CK_FloatingRealToComplex;
5118     case Type::STK_IntegralComplex:
5119       Src = ImpCastExprToType(Src.get(),
5120                               DestTy->castAs<ComplexType>()->getElementType(),
5121                               CK_FloatingToIntegral);
5122       return CK_IntegralRealToComplex;
5123     case Type::STK_CPointer:
5124     case Type::STK_ObjCObjectPointer:
5125     case Type::STK_BlockPointer:
5126       llvm_unreachable("valid float->pointer cast?");
5127     case Type::STK_MemberPointer:
5128       llvm_unreachable("member pointer type in C");
5129     }
5130     llvm_unreachable("Should have returned before this");
5131 
5132   case Type::STK_FloatingComplex:
5133     switch (DestTy->getScalarTypeKind()) {
5134     case Type::STK_FloatingComplex:
5135       return CK_FloatingComplexCast;
5136     case Type::STK_IntegralComplex:
5137       return CK_FloatingComplexToIntegralComplex;
5138     case Type::STK_Floating: {
5139       QualType ET = SrcTy->castAs<ComplexType>()->getElementType();
5140       if (Context.hasSameType(ET, DestTy))
5141         return CK_FloatingComplexToReal;
5142       Src = ImpCastExprToType(Src.get(), ET, CK_FloatingComplexToReal);
5143       return CK_FloatingCast;
5144     }
5145     case Type::STK_Bool:
5146       return CK_FloatingComplexToBoolean;
5147     case Type::STK_Integral:
5148       Src = ImpCastExprToType(Src.get(),
5149                               SrcTy->castAs<ComplexType>()->getElementType(),
5150                               CK_FloatingComplexToReal);
5151       return CK_FloatingToIntegral;
5152     case Type::STK_CPointer:
5153     case Type::STK_ObjCObjectPointer:
5154     case Type::STK_BlockPointer:
5155       llvm_unreachable("valid complex float->pointer cast?");
5156     case Type::STK_MemberPointer:
5157       llvm_unreachable("member pointer type in C");
5158     }
5159     llvm_unreachable("Should have returned before this");
5160 
5161   case Type::STK_IntegralComplex:
5162     switch (DestTy->getScalarTypeKind()) {
5163     case Type::STK_FloatingComplex:
5164       return CK_IntegralComplexToFloatingComplex;
5165     case Type::STK_IntegralComplex:
5166       return CK_IntegralComplexCast;
5167     case Type::STK_Integral: {
5168       QualType ET = SrcTy->castAs<ComplexType>()->getElementType();
5169       if (Context.hasSameType(ET, DestTy))
5170         return CK_IntegralComplexToReal;
5171       Src = ImpCastExprToType(Src.get(), ET, CK_IntegralComplexToReal);
5172       return CK_IntegralCast;
5173     }
5174     case Type::STK_Bool:
5175       return CK_IntegralComplexToBoolean;
5176     case Type::STK_Floating:
5177       Src = ImpCastExprToType(Src.get(),
5178                               SrcTy->castAs<ComplexType>()->getElementType(),
5179                               CK_IntegralComplexToReal);
5180       return CK_IntegralToFloating;
5181     case Type::STK_CPointer:
5182     case Type::STK_ObjCObjectPointer:
5183     case Type::STK_BlockPointer:
5184       llvm_unreachable("valid complex int->pointer cast?");
5185     case Type::STK_MemberPointer:
5186       llvm_unreachable("member pointer type in C");
5187     }
5188     llvm_unreachable("Should have returned before this");
5189   }
5190 
5191   llvm_unreachable("Unhandled scalar cast");
5192 }
5193 
breakDownVectorType(QualType type,uint64_t & len,QualType & eltType)5194 static bool breakDownVectorType(QualType type, uint64_t &len,
5195                                 QualType &eltType) {
5196   // Vectors are simple.
5197   if (const VectorType *vecType = type->getAs<VectorType>()) {
5198     len = vecType->getNumElements();
5199     eltType = vecType->getElementType();
5200     assert(eltType->isScalarType());
5201     return true;
5202   }
5203 
5204   // We allow lax conversion to and from non-vector types, but only if
5205   // they're real types (i.e. non-complex, non-pointer scalar types).
5206   if (!type->isRealType()) return false;
5207 
5208   len = 1;
5209   eltType = type;
5210   return true;
5211 }
5212 
VectorTypesMatch(Sema & S,QualType srcTy,QualType destTy)5213 static bool VectorTypesMatch(Sema &S, QualType srcTy, QualType destTy) {
5214   uint64_t srcLen, destLen;
5215   QualType srcElt, destElt;
5216   if (!breakDownVectorType(srcTy, srcLen, srcElt)) return false;
5217   if (!breakDownVectorType(destTy, destLen, destElt)) return false;
5218 
5219   // ASTContext::getTypeSize will return the size rounded up to a
5220   // power of 2, so instead of using that, we need to use the raw
5221   // element size multiplied by the element count.
5222   uint64_t srcEltSize = S.Context.getTypeSize(srcElt);
5223   uint64_t destEltSize = S.Context.getTypeSize(destElt);
5224 
5225   return (srcLen * srcEltSize == destLen * destEltSize);
5226 }
5227 
5228 /// Is this a legal conversion between two known vector types?
isLaxVectorConversion(QualType srcTy,QualType destTy)5229 bool Sema::isLaxVectorConversion(QualType srcTy, QualType destTy) {
5230   assert(destTy->isVectorType() || srcTy->isVectorType());
5231 
5232   if (!Context.getLangOpts().LaxVectorConversions)
5233     return false;
5234   return VectorTypesMatch(*this, srcTy, destTy);
5235 }
5236 
CheckVectorCast(SourceRange R,QualType VectorTy,QualType Ty,CastKind & Kind)5237 bool Sema::CheckVectorCast(SourceRange R, QualType VectorTy, QualType Ty,
5238                            CastKind &Kind) {
5239   assert(VectorTy->isVectorType() && "Not a vector type!");
5240 
5241   if (Ty->isVectorType() || Ty->isIntegerType()) {
5242     if (!VectorTypesMatch(*this, Ty, VectorTy))
5243       return Diag(R.getBegin(),
5244                   Ty->isVectorType() ?
5245                   diag::err_invalid_conversion_between_vectors :
5246                   diag::err_invalid_conversion_between_vector_and_integer)
5247         << VectorTy << Ty << R;
5248   } else
5249     return Diag(R.getBegin(),
5250                 diag::err_invalid_conversion_between_vector_and_scalar)
5251       << VectorTy << Ty << R;
5252 
5253   Kind = CK_BitCast;
5254   return false;
5255 }
5256 
CheckExtVectorCast(SourceRange R,QualType DestTy,Expr * CastExpr,CastKind & Kind)5257 ExprResult Sema::CheckExtVectorCast(SourceRange R, QualType DestTy,
5258                                     Expr *CastExpr, CastKind &Kind) {
5259   assert(DestTy->isExtVectorType() && "Not an extended vector type!");
5260 
5261   QualType SrcTy = CastExpr->getType();
5262 
5263   // If SrcTy is a VectorType, the total size must match to explicitly cast to
5264   // an ExtVectorType.
5265   // In OpenCL, casts between vectors of different types are not allowed.
5266   // (See OpenCL 6.2).
5267   if (SrcTy->isVectorType()) {
5268     if (!VectorTypesMatch(*this, SrcTy, DestTy)
5269         || (getLangOpts().OpenCL &&
5270             (DestTy.getCanonicalType() != SrcTy.getCanonicalType()))) {
5271       Diag(R.getBegin(),diag::err_invalid_conversion_between_ext_vectors)
5272         << DestTy << SrcTy << R;
5273       return ExprError();
5274     }
5275     Kind = CK_BitCast;
5276     return CastExpr;
5277   }
5278 
5279   // All non-pointer scalars can be cast to ExtVector type.  The appropriate
5280   // conversion will take place first from scalar to elt type, and then
5281   // splat from elt type to vector.
5282   if (SrcTy->isPointerType())
5283     return Diag(R.getBegin(),
5284                 diag::err_invalid_conversion_between_vector_and_scalar)
5285       << DestTy << SrcTy << R;
5286 
5287   QualType DestElemTy = DestTy->getAs<ExtVectorType>()->getElementType();
5288   ExprResult CastExprRes = CastExpr;
5289   CastKind CK = PrepareScalarCast(CastExprRes, DestElemTy);
5290   if (CastExprRes.isInvalid())
5291     return ExprError();
5292   CastExpr = ImpCastExprToType(CastExprRes.get(), DestElemTy, CK).get();
5293 
5294   Kind = CK_VectorSplat;
5295   return CastExpr;
5296 }
5297 
5298 ExprResult
ActOnCastExpr(Scope * S,SourceLocation LParenLoc,Declarator & D,ParsedType & Ty,SourceLocation RParenLoc,Expr * CastExpr)5299 Sema::ActOnCastExpr(Scope *S, SourceLocation LParenLoc,
5300                     Declarator &D, ParsedType &Ty,
5301                     SourceLocation RParenLoc, Expr *CastExpr) {
5302   assert(!D.isInvalidType() && (CastExpr != nullptr) &&
5303          "ActOnCastExpr(): missing type or expr");
5304 
5305   TypeSourceInfo *castTInfo = GetTypeForDeclaratorCast(D, CastExpr->getType());
5306   if (D.isInvalidType())
5307     return ExprError();
5308 
5309   if (getLangOpts().CPlusPlus) {
5310     // Check that there are no default arguments (C++ only).
5311     CheckExtraCXXDefaultArguments(D);
5312   } else {
5313     // Make sure any TypoExprs have been dealt with.
5314     ExprResult Res = CorrectDelayedTyposInExpr(CastExpr);
5315     if (!Res.isUsable())
5316       return ExprError();
5317     CastExpr = Res.get();
5318   }
5319 
5320   checkUnusedDeclAttributes(D);
5321 
5322   QualType castType = castTInfo->getType();
5323   Ty = CreateParsedType(castType, castTInfo);
5324 
5325   bool isVectorLiteral = false;
5326 
5327   // Check for an altivec or OpenCL literal,
5328   // i.e. all the elements are integer constants.
5329   ParenExpr *PE = dyn_cast<ParenExpr>(CastExpr);
5330   ParenListExpr *PLE = dyn_cast<ParenListExpr>(CastExpr);
5331   if ((getLangOpts().AltiVec || getLangOpts().OpenCL)
5332        && castType->isVectorType() && (PE || PLE)) {
5333     if (PLE && PLE->getNumExprs() == 0) {
5334       Diag(PLE->getExprLoc(), diag::err_altivec_empty_initializer);
5335       return ExprError();
5336     }
5337     if (PE || PLE->getNumExprs() == 1) {
5338       Expr *E = (PE ? PE->getSubExpr() : PLE->getExpr(0));
5339       if (!E->getType()->isVectorType())
5340         isVectorLiteral = true;
5341     }
5342     else
5343       isVectorLiteral = true;
5344   }
5345 
5346   // If this is a vector initializer, '(' type ')' '(' init, ..., init ')'
5347   // then handle it as such.
5348   if (isVectorLiteral)
5349     return BuildVectorLiteral(LParenLoc, RParenLoc, CastExpr, castTInfo);
5350 
5351   // If the Expr being casted is a ParenListExpr, handle it specially.
5352   // This is not an AltiVec-style cast, so turn the ParenListExpr into a
5353   // sequence of BinOp comma operators.
5354   if (isa<ParenListExpr>(CastExpr)) {
5355     ExprResult Result = MaybeConvertParenListExprToParenExpr(S, CastExpr);
5356     if (Result.isInvalid()) return ExprError();
5357     CastExpr = Result.get();
5358   }
5359 
5360   if (getLangOpts().CPlusPlus && !castType->isVoidType() &&
5361       !getSourceManager().isInSystemMacro(LParenLoc))
5362     Diag(LParenLoc, diag::warn_old_style_cast) << CastExpr->getSourceRange();
5363 
5364   CheckTollFreeBridgeCast(castType, CastExpr);
5365 
5366   CheckObjCBridgeRelatedCast(castType, CastExpr);
5367 
5368   return BuildCStyleCastExpr(LParenLoc, castTInfo, RParenLoc, CastExpr);
5369 }
5370 
BuildVectorLiteral(SourceLocation LParenLoc,SourceLocation RParenLoc,Expr * E,TypeSourceInfo * TInfo)5371 ExprResult Sema::BuildVectorLiteral(SourceLocation LParenLoc,
5372                                     SourceLocation RParenLoc, Expr *E,
5373                                     TypeSourceInfo *TInfo) {
5374   assert((isa<ParenListExpr>(E) || isa<ParenExpr>(E)) &&
5375          "Expected paren or paren list expression");
5376 
5377   Expr **exprs;
5378   unsigned numExprs;
5379   Expr *subExpr;
5380   SourceLocation LiteralLParenLoc, LiteralRParenLoc;
5381   if (ParenListExpr *PE = dyn_cast<ParenListExpr>(E)) {
5382     LiteralLParenLoc = PE->getLParenLoc();
5383     LiteralRParenLoc = PE->getRParenLoc();
5384     exprs = PE->getExprs();
5385     numExprs = PE->getNumExprs();
5386   } else { // isa<ParenExpr> by assertion at function entrance
5387     LiteralLParenLoc = cast<ParenExpr>(E)->getLParen();
5388     LiteralRParenLoc = cast<ParenExpr>(E)->getRParen();
5389     subExpr = cast<ParenExpr>(E)->getSubExpr();
5390     exprs = &subExpr;
5391     numExprs = 1;
5392   }
5393 
5394   QualType Ty = TInfo->getType();
5395   assert(Ty->isVectorType() && "Expected vector type");
5396 
5397   SmallVector<Expr *, 8> initExprs;
5398   const VectorType *VTy = Ty->getAs<VectorType>();
5399   unsigned numElems = Ty->getAs<VectorType>()->getNumElements();
5400 
5401   // '(...)' form of vector initialization in AltiVec: the number of
5402   // initializers must be one or must match the size of the vector.
5403   // If a single value is specified in the initializer then it will be
5404   // replicated to all the components of the vector
5405   if (VTy->getVectorKind() == VectorType::AltiVecVector) {
5406     // The number of initializers must be one or must match the size of the
5407     // vector. If a single value is specified in the initializer then it will
5408     // be replicated to all the components of the vector
5409     if (numExprs == 1) {
5410       QualType ElemTy = Ty->getAs<VectorType>()->getElementType();
5411       ExprResult Literal = DefaultLvalueConversion(exprs[0]);
5412       if (Literal.isInvalid())
5413         return ExprError();
5414       Literal = ImpCastExprToType(Literal.get(), ElemTy,
5415                                   PrepareScalarCast(Literal, ElemTy));
5416       return BuildCStyleCastExpr(LParenLoc, TInfo, RParenLoc, Literal.get());
5417     }
5418     else if (numExprs < numElems) {
5419       Diag(E->getExprLoc(),
5420            diag::err_incorrect_number_of_vector_initializers);
5421       return ExprError();
5422     }
5423     else
5424       initExprs.append(exprs, exprs + numExprs);
5425   }
5426   else {
5427     // For OpenCL, when the number of initializers is a single value,
5428     // it will be replicated to all components of the vector.
5429     if (getLangOpts().OpenCL &&
5430         VTy->getVectorKind() == VectorType::GenericVector &&
5431         numExprs == 1) {
5432         QualType ElemTy = Ty->getAs<VectorType>()->getElementType();
5433         ExprResult Literal = DefaultLvalueConversion(exprs[0]);
5434         if (Literal.isInvalid())
5435           return ExprError();
5436         Literal = ImpCastExprToType(Literal.get(), ElemTy,
5437                                     PrepareScalarCast(Literal, ElemTy));
5438         return BuildCStyleCastExpr(LParenLoc, TInfo, RParenLoc, Literal.get());
5439     }
5440 
5441     initExprs.append(exprs, exprs + numExprs);
5442   }
5443   // FIXME: This means that pretty-printing the final AST will produce curly
5444   // braces instead of the original commas.
5445   InitListExpr *initE = new (Context) InitListExpr(Context, LiteralLParenLoc,
5446                                                    initExprs, LiteralRParenLoc);
5447   initE->setType(Ty);
5448   return BuildCompoundLiteralExpr(LParenLoc, TInfo, RParenLoc, initE);
5449 }
5450 
5451 /// This is not an AltiVec-style cast or or C++ direct-initialization, so turn
5452 /// the ParenListExpr into a sequence of comma binary operators.
5453 ExprResult
MaybeConvertParenListExprToParenExpr(Scope * S,Expr * OrigExpr)5454 Sema::MaybeConvertParenListExprToParenExpr(Scope *S, Expr *OrigExpr) {
5455   ParenListExpr *E = dyn_cast<ParenListExpr>(OrigExpr);
5456   if (!E)
5457     return OrigExpr;
5458 
5459   ExprResult Result(E->getExpr(0));
5460 
5461   for (unsigned i = 1, e = E->getNumExprs(); i != e && !Result.isInvalid(); ++i)
5462     Result = ActOnBinOp(S, E->getExprLoc(), tok::comma, Result.get(),
5463                         E->getExpr(i));
5464 
5465   if (Result.isInvalid()) return ExprError();
5466 
5467   return ActOnParenExpr(E->getLParenLoc(), E->getRParenLoc(), Result.get());
5468 }
5469 
ActOnParenListExpr(SourceLocation L,SourceLocation R,MultiExprArg Val)5470 ExprResult Sema::ActOnParenListExpr(SourceLocation L,
5471                                     SourceLocation R,
5472                                     MultiExprArg Val) {
5473   Expr *expr = new (Context) ParenListExpr(Context, L, Val, R);
5474   return expr;
5475 }
5476 
5477 /// \brief Emit a specialized diagnostic when one expression is a null pointer
5478 /// constant and the other is not a pointer.  Returns true if a diagnostic is
5479 /// emitted.
DiagnoseConditionalForNull(Expr * LHSExpr,Expr * RHSExpr,SourceLocation QuestionLoc)5480 bool Sema::DiagnoseConditionalForNull(Expr *LHSExpr, Expr *RHSExpr,
5481                                       SourceLocation QuestionLoc) {
5482   Expr *NullExpr = LHSExpr;
5483   Expr *NonPointerExpr = RHSExpr;
5484   Expr::NullPointerConstantKind NullKind =
5485       NullExpr->isNullPointerConstant(Context,
5486                                       Expr::NPC_ValueDependentIsNotNull);
5487 
5488   if (NullKind == Expr::NPCK_NotNull) {
5489     NullExpr = RHSExpr;
5490     NonPointerExpr = LHSExpr;
5491     NullKind =
5492         NullExpr->isNullPointerConstant(Context,
5493                                         Expr::NPC_ValueDependentIsNotNull);
5494   }
5495 
5496   if (NullKind == Expr::NPCK_NotNull)
5497     return false;
5498 
5499   if (NullKind == Expr::NPCK_ZeroExpression)
5500     return false;
5501 
5502   if (NullKind == Expr::NPCK_ZeroLiteral) {
5503     // In this case, check to make sure that we got here from a "NULL"
5504     // string in the source code.
5505     NullExpr = NullExpr->IgnoreParenImpCasts();
5506     SourceLocation loc = NullExpr->getExprLoc();
5507     if (!findMacroSpelling(loc, "NULL"))
5508       return false;
5509   }
5510 
5511   int DiagType = (NullKind == Expr::NPCK_CXX11_nullptr);
5512   Diag(QuestionLoc, diag::err_typecheck_cond_incompatible_operands_null)
5513       << NonPointerExpr->getType() << DiagType
5514       << NonPointerExpr->getSourceRange();
5515   return true;
5516 }
5517 
5518 /// \brief Return false if the condition expression is valid, true otherwise.
checkCondition(Sema & S,Expr * Cond)5519 static bool checkCondition(Sema &S, Expr *Cond) {
5520   QualType CondTy = Cond->getType();
5521 
5522   // C99 6.5.15p2
5523   if (CondTy->isScalarType()) return false;
5524 
5525   // OpenCL v1.1 s6.3.i says the condition is allowed to be a vector or scalar.
5526   if (S.getLangOpts().OpenCL && CondTy->isVectorType())
5527     return false;
5528 
5529   // Emit the proper error message.
5530   S.Diag(Cond->getLocStart(), S.getLangOpts().OpenCL ?
5531                               diag::err_typecheck_cond_expect_scalar :
5532                               diag::err_typecheck_cond_expect_scalar_or_vector)
5533     << CondTy;
5534   return true;
5535 }
5536 
5537 /// \brief Return false if the two expressions can be converted to a vector,
5538 /// true otherwise
checkConditionalConvertScalarsToVectors(Sema & S,ExprResult & LHS,ExprResult & RHS,QualType CondTy)5539 static bool checkConditionalConvertScalarsToVectors(Sema &S, ExprResult &LHS,
5540                                                     ExprResult &RHS,
5541                                                     QualType CondTy) {
5542   // Both operands should be of scalar type.
5543   if (!LHS.get()->getType()->isScalarType()) {
5544     S.Diag(LHS.get()->getLocStart(), diag::err_typecheck_cond_expect_scalar)
5545       << CondTy;
5546     return true;
5547   }
5548   if (!RHS.get()->getType()->isScalarType()) {
5549     S.Diag(RHS.get()->getLocStart(), diag::err_typecheck_cond_expect_scalar)
5550       << CondTy;
5551     return true;
5552   }
5553 
5554   // Implicity convert these scalars to the type of the condition.
5555   LHS = S.ImpCastExprToType(LHS.get(), CondTy, CK_IntegralCast);
5556   RHS = S.ImpCastExprToType(RHS.get(), CondTy, CK_IntegralCast);
5557   return false;
5558 }
5559 
5560 /// \brief Handle when one or both operands are void type.
checkConditionalVoidType(Sema & S,ExprResult & LHS,ExprResult & RHS)5561 static QualType checkConditionalVoidType(Sema &S, ExprResult &LHS,
5562                                          ExprResult &RHS) {
5563     Expr *LHSExpr = LHS.get();
5564     Expr *RHSExpr = RHS.get();
5565 
5566     if (!LHSExpr->getType()->isVoidType())
5567       S.Diag(RHSExpr->getLocStart(), diag::ext_typecheck_cond_one_void)
5568         << RHSExpr->getSourceRange();
5569     if (!RHSExpr->getType()->isVoidType())
5570       S.Diag(LHSExpr->getLocStart(), diag::ext_typecheck_cond_one_void)
5571         << LHSExpr->getSourceRange();
5572     LHS = S.ImpCastExprToType(LHS.get(), S.Context.VoidTy, CK_ToVoid);
5573     RHS = S.ImpCastExprToType(RHS.get(), S.Context.VoidTy, CK_ToVoid);
5574     return S.Context.VoidTy;
5575 }
5576 
5577 /// \brief Return false if the NullExpr can be promoted to PointerTy,
5578 /// true otherwise.
checkConditionalNullPointer(Sema & S,ExprResult & NullExpr,QualType PointerTy)5579 static bool checkConditionalNullPointer(Sema &S, ExprResult &NullExpr,
5580                                         QualType PointerTy) {
5581   if ((!PointerTy->isAnyPointerType() && !PointerTy->isBlockPointerType()) ||
5582       !NullExpr.get()->isNullPointerConstant(S.Context,
5583                                             Expr::NPC_ValueDependentIsNull))
5584     return true;
5585 
5586   NullExpr = S.ImpCastExprToType(NullExpr.get(), PointerTy, CK_NullToPointer);
5587   return false;
5588 }
5589 
5590 /// \brief Checks compatibility between two pointers and return the resulting
5591 /// type.
checkConditionalPointerCompatibility(Sema & S,ExprResult & LHS,ExprResult & RHS,SourceLocation Loc)5592 static QualType checkConditionalPointerCompatibility(Sema &S, ExprResult &LHS,
5593                                                      ExprResult &RHS,
5594                                                      SourceLocation Loc) {
5595   QualType LHSTy = LHS.get()->getType();
5596   QualType RHSTy = RHS.get()->getType();
5597 
5598   if (S.Context.hasSameType(LHSTy, RHSTy)) {
5599     // Two identical pointers types are always compatible.
5600     return LHSTy;
5601   }
5602 
5603   QualType lhptee, rhptee;
5604 
5605   // Get the pointee types.
5606   bool IsBlockPointer = false;
5607   if (const BlockPointerType *LHSBTy = LHSTy->getAs<BlockPointerType>()) {
5608     lhptee = LHSBTy->getPointeeType();
5609     rhptee = RHSTy->castAs<BlockPointerType>()->getPointeeType();
5610     IsBlockPointer = true;
5611   } else {
5612     lhptee = LHSTy->castAs<PointerType>()->getPointeeType();
5613     rhptee = RHSTy->castAs<PointerType>()->getPointeeType();
5614   }
5615 
5616   // C99 6.5.15p6: If both operands are pointers to compatible types or to
5617   // differently qualified versions of compatible types, the result type is
5618   // a pointer to an appropriately qualified version of the composite
5619   // type.
5620 
5621   // Only CVR-qualifiers exist in the standard, and the differently-qualified
5622   // clause doesn't make sense for our extensions. E.g. address space 2 should
5623   // be incompatible with address space 3: they may live on different devices or
5624   // anything.
5625   Qualifiers lhQual = lhptee.getQualifiers();
5626   Qualifiers rhQual = rhptee.getQualifiers();
5627 
5628   unsigned MergedCVRQual = lhQual.getCVRQualifiers() | rhQual.getCVRQualifiers();
5629   lhQual.removeCVRQualifiers();
5630   rhQual.removeCVRQualifiers();
5631 
5632   lhptee = S.Context.getQualifiedType(lhptee.getUnqualifiedType(), lhQual);
5633   rhptee = S.Context.getQualifiedType(rhptee.getUnqualifiedType(), rhQual);
5634 
5635   QualType CompositeTy = S.Context.mergeTypes(lhptee, rhptee);
5636 
5637   if (CompositeTy.isNull()) {
5638     S.Diag(Loc, diag::ext_typecheck_cond_incompatible_pointers)
5639       << LHSTy << RHSTy << LHS.get()->getSourceRange()
5640       << RHS.get()->getSourceRange();
5641     // In this situation, we assume void* type. No especially good
5642     // reason, but this is what gcc does, and we do have to pick
5643     // to get a consistent AST.
5644     QualType incompatTy = S.Context.getPointerType(S.Context.VoidTy);
5645     LHS = S.ImpCastExprToType(LHS.get(), incompatTy, CK_BitCast);
5646     RHS = S.ImpCastExprToType(RHS.get(), incompatTy, CK_BitCast);
5647     return incompatTy;
5648   }
5649 
5650   // The pointer types are compatible.
5651   QualType ResultTy = CompositeTy.withCVRQualifiers(MergedCVRQual);
5652   if (IsBlockPointer)
5653     ResultTy = S.Context.getBlockPointerType(ResultTy);
5654   else
5655     ResultTy = S.Context.getPointerType(ResultTy);
5656 
5657   LHS = S.ImpCastExprToType(LHS.get(), ResultTy, CK_BitCast);
5658   RHS = S.ImpCastExprToType(RHS.get(), ResultTy, CK_BitCast);
5659   return ResultTy;
5660 }
5661 
5662 /// \brief Returns true if QT is quelified-id and implements 'NSObject' and/or
5663 /// 'NSCopying' protocols (and nothing else); or QT is an NSObject and optionally
5664 /// implements 'NSObject' and/or NSCopying' protocols (and nothing else).
isObjCPtrBlockCompatible(Sema & S,ASTContext & C,QualType QT)5665 static bool isObjCPtrBlockCompatible(Sema &S, ASTContext &C, QualType QT) {
5666   if (QT->isObjCIdType())
5667     return true;
5668 
5669   const ObjCObjectPointerType *OPT = QT->getAs<ObjCObjectPointerType>();
5670   if (!OPT)
5671     return false;
5672 
5673   if (ObjCInterfaceDecl *ID = OPT->getInterfaceDecl())
5674     if (ID->getIdentifier() != &C.Idents.get("NSObject"))
5675       return false;
5676 
5677   ObjCProtocolDecl* PNSCopying =
5678     S.LookupProtocol(&C.Idents.get("NSCopying"), SourceLocation());
5679   ObjCProtocolDecl* PNSObject =
5680     S.LookupProtocol(&C.Idents.get("NSObject"), SourceLocation());
5681 
5682   for (auto *Proto : OPT->quals()) {
5683     if ((PNSCopying && declaresSameEntity(Proto, PNSCopying)) ||
5684         (PNSObject && declaresSameEntity(Proto, PNSObject)))
5685       ;
5686     else
5687       return false;
5688   }
5689   return true;
5690 }
5691 
5692 /// \brief Return the resulting type when the operands are both block pointers.
checkConditionalBlockPointerCompatibility(Sema & S,ExprResult & LHS,ExprResult & RHS,SourceLocation Loc)5693 static QualType checkConditionalBlockPointerCompatibility(Sema &S,
5694                                                           ExprResult &LHS,
5695                                                           ExprResult &RHS,
5696                                                           SourceLocation Loc) {
5697   QualType LHSTy = LHS.get()->getType();
5698   QualType RHSTy = RHS.get()->getType();
5699 
5700   if (!LHSTy->isBlockPointerType() || !RHSTy->isBlockPointerType()) {
5701     if (LHSTy->isVoidPointerType() || RHSTy->isVoidPointerType()) {
5702       QualType destType = S.Context.getPointerType(S.Context.VoidTy);
5703       LHS = S.ImpCastExprToType(LHS.get(), destType, CK_BitCast);
5704       RHS = S.ImpCastExprToType(RHS.get(), destType, CK_BitCast);
5705       return destType;
5706     }
5707     S.Diag(Loc, diag::err_typecheck_cond_incompatible_operands)
5708       << LHSTy << RHSTy << LHS.get()->getSourceRange()
5709       << RHS.get()->getSourceRange();
5710     return QualType();
5711   }
5712 
5713   // We have 2 block pointer types.
5714   return checkConditionalPointerCompatibility(S, LHS, RHS, Loc);
5715 }
5716 
5717 /// \brief Return the resulting type when the operands are both pointers.
5718 static QualType
checkConditionalObjectPointersCompatibility(Sema & S,ExprResult & LHS,ExprResult & RHS,SourceLocation Loc)5719 checkConditionalObjectPointersCompatibility(Sema &S, ExprResult &LHS,
5720                                             ExprResult &RHS,
5721                                             SourceLocation Loc) {
5722   // get the pointer types
5723   QualType LHSTy = LHS.get()->getType();
5724   QualType RHSTy = RHS.get()->getType();
5725 
5726   // get the "pointed to" types
5727   QualType lhptee = LHSTy->getAs<PointerType>()->getPointeeType();
5728   QualType rhptee = RHSTy->getAs<PointerType>()->getPointeeType();
5729 
5730   // ignore qualifiers on void (C99 6.5.15p3, clause 6)
5731   if (lhptee->isVoidType() && rhptee->isIncompleteOrObjectType()) {
5732     // Figure out necessary qualifiers (C99 6.5.15p6)
5733     QualType destPointee
5734       = S.Context.getQualifiedType(lhptee, rhptee.getQualifiers());
5735     QualType destType = S.Context.getPointerType(destPointee);
5736     // Add qualifiers if necessary.
5737     LHS = S.ImpCastExprToType(LHS.get(), destType, CK_NoOp);
5738     // Promote to void*.
5739     RHS = S.ImpCastExprToType(RHS.get(), destType, CK_BitCast);
5740     return destType;
5741   }
5742   if (rhptee->isVoidType() && lhptee->isIncompleteOrObjectType()) {
5743     QualType destPointee
5744       = S.Context.getQualifiedType(rhptee, lhptee.getQualifiers());
5745     QualType destType = S.Context.getPointerType(destPointee);
5746     // Add qualifiers if necessary.
5747     RHS = S.ImpCastExprToType(RHS.get(), destType, CK_NoOp);
5748     // Promote to void*.
5749     LHS = S.ImpCastExprToType(LHS.get(), destType, CK_BitCast);
5750     return destType;
5751   }
5752 
5753   return checkConditionalPointerCompatibility(S, LHS, RHS, Loc);
5754 }
5755 
5756 /// \brief Return false if the first expression is not an integer and the second
5757 /// expression is not a pointer, true otherwise.
checkPointerIntegerMismatch(Sema & S,ExprResult & Int,Expr * PointerExpr,SourceLocation Loc,bool IsIntFirstExpr)5758 static bool checkPointerIntegerMismatch(Sema &S, ExprResult &Int,
5759                                         Expr* PointerExpr, SourceLocation Loc,
5760                                         bool IsIntFirstExpr) {
5761   if (!PointerExpr->getType()->isPointerType() ||
5762       !Int.get()->getType()->isIntegerType())
5763     return false;
5764 
5765   Expr *Expr1 = IsIntFirstExpr ? Int.get() : PointerExpr;
5766   Expr *Expr2 = IsIntFirstExpr ? PointerExpr : Int.get();
5767 
5768   S.Diag(Loc, diag::ext_typecheck_cond_pointer_integer_mismatch)
5769     << Expr1->getType() << Expr2->getType()
5770     << Expr1->getSourceRange() << Expr2->getSourceRange();
5771   Int = S.ImpCastExprToType(Int.get(), PointerExpr->getType(),
5772                             CK_IntegralToPointer);
5773   return true;
5774 }
5775 
5776 /// Note that LHS is not null here, even if this is the gnu "x ?: y" extension.
5777 /// In that case, LHS = cond.
5778 /// C99 6.5.15
CheckConditionalOperands(ExprResult & Cond,ExprResult & LHS,ExprResult & RHS,ExprValueKind & VK,ExprObjectKind & OK,SourceLocation QuestionLoc)5779 QualType Sema::CheckConditionalOperands(ExprResult &Cond, ExprResult &LHS,
5780                                         ExprResult &RHS, ExprValueKind &VK,
5781                                         ExprObjectKind &OK,
5782                                         SourceLocation QuestionLoc) {
5783 
5784   ExprResult LHSResult = CheckPlaceholderExpr(LHS.get());
5785   if (!LHSResult.isUsable()) return QualType();
5786   LHS = LHSResult;
5787 
5788   ExprResult RHSResult = CheckPlaceholderExpr(RHS.get());
5789   if (!RHSResult.isUsable()) return QualType();
5790   RHS = RHSResult;
5791 
5792   // C++ is sufficiently different to merit its own checker.
5793   if (getLangOpts().CPlusPlus)
5794     return CXXCheckConditionalOperands(Cond, LHS, RHS, VK, OK, QuestionLoc);
5795 
5796   VK = VK_RValue;
5797   OK = OK_Ordinary;
5798 
5799   // First, check the condition.
5800   Cond = UsualUnaryConversions(Cond.get());
5801   if (Cond.isInvalid())
5802     return QualType();
5803   if (checkCondition(*this, Cond.get()))
5804     return QualType();
5805 
5806   // Now check the two expressions.
5807   if (LHS.get()->getType()->isVectorType() ||
5808       RHS.get()->getType()->isVectorType())
5809     return CheckVectorOperands(LHS, RHS, QuestionLoc, /*isCompAssign*/false);
5810 
5811   QualType ResTy = UsualArithmeticConversions(LHS, RHS);
5812   if (LHS.isInvalid() || RHS.isInvalid())
5813     return QualType();
5814 
5815   QualType CondTy = Cond.get()->getType();
5816   QualType LHSTy = LHS.get()->getType();
5817   QualType RHSTy = RHS.get()->getType();
5818 
5819   // If the condition is a vector, and both operands are scalar,
5820   // attempt to implicity convert them to the vector type to act like the
5821   // built in select. (OpenCL v1.1 s6.3.i)
5822   if (getLangOpts().OpenCL && CondTy->isVectorType())
5823     if (checkConditionalConvertScalarsToVectors(*this, LHS, RHS, CondTy))
5824       return QualType();
5825 
5826   // If both operands have arithmetic type, do the usual arithmetic conversions
5827   // to find a common type: C99 6.5.15p3,5.
5828   if (LHSTy->isArithmeticType() && RHSTy->isArithmeticType()) {
5829     LHS = ImpCastExprToType(LHS.get(), ResTy, PrepareScalarCast(LHS, ResTy));
5830     RHS = ImpCastExprToType(RHS.get(), ResTy, PrepareScalarCast(RHS, ResTy));
5831 
5832     return ResTy;
5833   }
5834 
5835   // If both operands are the same structure or union type, the result is that
5836   // type.
5837   if (const RecordType *LHSRT = LHSTy->getAs<RecordType>()) {    // C99 6.5.15p3
5838     if (const RecordType *RHSRT = RHSTy->getAs<RecordType>())
5839       if (LHSRT->getDecl() == RHSRT->getDecl())
5840         // "If both the operands have structure or union type, the result has
5841         // that type."  This implies that CV qualifiers are dropped.
5842         return LHSTy.getUnqualifiedType();
5843     // FIXME: Type of conditional expression must be complete in C mode.
5844   }
5845 
5846   // C99 6.5.15p5: "If both operands have void type, the result has void type."
5847   // The following || allows only one side to be void (a GCC-ism).
5848   if (LHSTy->isVoidType() || RHSTy->isVoidType()) {
5849     return checkConditionalVoidType(*this, LHS, RHS);
5850   }
5851 
5852   // C99 6.5.15p6 - "if one operand is a null pointer constant, the result has
5853   // the type of the other operand."
5854   if (!checkConditionalNullPointer(*this, RHS, LHSTy)) return LHSTy;
5855   if (!checkConditionalNullPointer(*this, LHS, RHSTy)) return RHSTy;
5856 
5857   // All objective-c pointer type analysis is done here.
5858   QualType compositeType = FindCompositeObjCPointerType(LHS, RHS,
5859                                                         QuestionLoc);
5860   if (LHS.isInvalid() || RHS.isInvalid())
5861     return QualType();
5862   if (!compositeType.isNull())
5863     return compositeType;
5864 
5865 
5866   // Handle block pointer types.
5867   if (LHSTy->isBlockPointerType() || RHSTy->isBlockPointerType())
5868     return checkConditionalBlockPointerCompatibility(*this, LHS, RHS,
5869                                                      QuestionLoc);
5870 
5871   // Check constraints for C object pointers types (C99 6.5.15p3,6).
5872   if (LHSTy->isPointerType() && RHSTy->isPointerType())
5873     return checkConditionalObjectPointersCompatibility(*this, LHS, RHS,
5874                                                        QuestionLoc);
5875 
5876   // GCC compatibility: soften pointer/integer mismatch.  Note that
5877   // null pointers have been filtered out by this point.
5878   if (checkPointerIntegerMismatch(*this, LHS, RHS.get(), QuestionLoc,
5879       /*isIntFirstExpr=*/true))
5880     return RHSTy;
5881   if (checkPointerIntegerMismatch(*this, RHS, LHS.get(), QuestionLoc,
5882       /*isIntFirstExpr=*/false))
5883     return LHSTy;
5884 
5885   // Emit a better diagnostic if one of the expressions is a null pointer
5886   // constant and the other is not a pointer type. In this case, the user most
5887   // likely forgot to take the address of the other expression.
5888   if (DiagnoseConditionalForNull(LHS.get(), RHS.get(), QuestionLoc))
5889     return QualType();
5890 
5891   // Otherwise, the operands are not compatible.
5892   Diag(QuestionLoc, diag::err_typecheck_cond_incompatible_operands)
5893     << LHSTy << RHSTy << LHS.get()->getSourceRange()
5894     << RHS.get()->getSourceRange();
5895   return QualType();
5896 }
5897 
5898 /// FindCompositeObjCPointerType - Helper method to find composite type of
5899 /// two objective-c pointer types of the two input expressions.
FindCompositeObjCPointerType(ExprResult & LHS,ExprResult & RHS,SourceLocation QuestionLoc)5900 QualType Sema::FindCompositeObjCPointerType(ExprResult &LHS, ExprResult &RHS,
5901                                             SourceLocation QuestionLoc) {
5902   QualType LHSTy = LHS.get()->getType();
5903   QualType RHSTy = RHS.get()->getType();
5904 
5905   // Handle things like Class and struct objc_class*.  Here we case the result
5906   // to the pseudo-builtin, because that will be implicitly cast back to the
5907   // redefinition type if an attempt is made to access its fields.
5908   if (LHSTy->isObjCClassType() &&
5909       (Context.hasSameType(RHSTy, Context.getObjCClassRedefinitionType()))) {
5910     RHS = ImpCastExprToType(RHS.get(), LHSTy, CK_CPointerToObjCPointerCast);
5911     return LHSTy;
5912   }
5913   if (RHSTy->isObjCClassType() &&
5914       (Context.hasSameType(LHSTy, Context.getObjCClassRedefinitionType()))) {
5915     LHS = ImpCastExprToType(LHS.get(), RHSTy, CK_CPointerToObjCPointerCast);
5916     return RHSTy;
5917   }
5918   // And the same for struct objc_object* / id
5919   if (LHSTy->isObjCIdType() &&
5920       (Context.hasSameType(RHSTy, Context.getObjCIdRedefinitionType()))) {
5921     RHS = ImpCastExprToType(RHS.get(), LHSTy, CK_CPointerToObjCPointerCast);
5922     return LHSTy;
5923   }
5924   if (RHSTy->isObjCIdType() &&
5925       (Context.hasSameType(LHSTy, Context.getObjCIdRedefinitionType()))) {
5926     LHS = ImpCastExprToType(LHS.get(), RHSTy, CK_CPointerToObjCPointerCast);
5927     return RHSTy;
5928   }
5929   // And the same for struct objc_selector* / SEL
5930   if (Context.isObjCSelType(LHSTy) &&
5931       (Context.hasSameType(RHSTy, Context.getObjCSelRedefinitionType()))) {
5932     RHS = ImpCastExprToType(RHS.get(), LHSTy, CK_BitCast);
5933     return LHSTy;
5934   }
5935   if (Context.isObjCSelType(RHSTy) &&
5936       (Context.hasSameType(LHSTy, Context.getObjCSelRedefinitionType()))) {
5937     LHS = ImpCastExprToType(LHS.get(), RHSTy, CK_BitCast);
5938     return RHSTy;
5939   }
5940   // Check constraints for Objective-C object pointers types.
5941   if (LHSTy->isObjCObjectPointerType() && RHSTy->isObjCObjectPointerType()) {
5942 
5943     if (Context.getCanonicalType(LHSTy) == Context.getCanonicalType(RHSTy)) {
5944       // Two identical object pointer types are always compatible.
5945       return LHSTy;
5946     }
5947     const ObjCObjectPointerType *LHSOPT = LHSTy->castAs<ObjCObjectPointerType>();
5948     const ObjCObjectPointerType *RHSOPT = RHSTy->castAs<ObjCObjectPointerType>();
5949     QualType compositeType = LHSTy;
5950 
5951     // If both operands are interfaces and either operand can be
5952     // assigned to the other, use that type as the composite
5953     // type. This allows
5954     //   xxx ? (A*) a : (B*) b
5955     // where B is a subclass of A.
5956     //
5957     // Additionally, as for assignment, if either type is 'id'
5958     // allow silent coercion. Finally, if the types are
5959     // incompatible then make sure to use 'id' as the composite
5960     // type so the result is acceptable for sending messages to.
5961 
5962     // FIXME: Consider unifying with 'areComparableObjCPointerTypes'.
5963     // It could return the composite type.
5964     if (Context.canAssignObjCInterfaces(LHSOPT, RHSOPT)) {
5965       compositeType = RHSOPT->isObjCBuiltinType() ? RHSTy : LHSTy;
5966     } else if (Context.canAssignObjCInterfaces(RHSOPT, LHSOPT)) {
5967       compositeType = LHSOPT->isObjCBuiltinType() ? LHSTy : RHSTy;
5968     } else if ((LHSTy->isObjCQualifiedIdType() ||
5969                 RHSTy->isObjCQualifiedIdType()) &&
5970                Context.ObjCQualifiedIdTypesAreCompatible(LHSTy, RHSTy, true)) {
5971       // Need to handle "id<xx>" explicitly.
5972       // GCC allows qualified id and any Objective-C type to devolve to
5973       // id. Currently localizing to here until clear this should be
5974       // part of ObjCQualifiedIdTypesAreCompatible.
5975       compositeType = Context.getObjCIdType();
5976     } else if (LHSTy->isObjCIdType() || RHSTy->isObjCIdType()) {
5977       compositeType = Context.getObjCIdType();
5978     } else if (!(compositeType =
5979                  Context.areCommonBaseCompatible(LHSOPT, RHSOPT)).isNull())
5980       ;
5981     else {
5982       Diag(QuestionLoc, diag::ext_typecheck_cond_incompatible_operands)
5983       << LHSTy << RHSTy
5984       << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
5985       QualType incompatTy = Context.getObjCIdType();
5986       LHS = ImpCastExprToType(LHS.get(), incompatTy, CK_BitCast);
5987       RHS = ImpCastExprToType(RHS.get(), incompatTy, CK_BitCast);
5988       return incompatTy;
5989     }
5990     // The object pointer types are compatible.
5991     LHS = ImpCastExprToType(LHS.get(), compositeType, CK_BitCast);
5992     RHS = ImpCastExprToType(RHS.get(), compositeType, CK_BitCast);
5993     return compositeType;
5994   }
5995   // Check Objective-C object pointer types and 'void *'
5996   if (LHSTy->isVoidPointerType() && RHSTy->isObjCObjectPointerType()) {
5997     if (getLangOpts().ObjCAutoRefCount) {
5998       // ARC forbids the implicit conversion of object pointers to 'void *',
5999       // so these types are not compatible.
6000       Diag(QuestionLoc, diag::err_cond_voidptr_arc) << LHSTy << RHSTy
6001           << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
6002       LHS = RHS = true;
6003       return QualType();
6004     }
6005     QualType lhptee = LHSTy->getAs<PointerType>()->getPointeeType();
6006     QualType rhptee = RHSTy->getAs<ObjCObjectPointerType>()->getPointeeType();
6007     QualType destPointee
6008     = Context.getQualifiedType(lhptee, rhptee.getQualifiers());
6009     QualType destType = Context.getPointerType(destPointee);
6010     // Add qualifiers if necessary.
6011     LHS = ImpCastExprToType(LHS.get(), destType, CK_NoOp);
6012     // Promote to void*.
6013     RHS = ImpCastExprToType(RHS.get(), destType, CK_BitCast);
6014     return destType;
6015   }
6016   if (LHSTy->isObjCObjectPointerType() && RHSTy->isVoidPointerType()) {
6017     if (getLangOpts().ObjCAutoRefCount) {
6018       // ARC forbids the implicit conversion of object pointers to 'void *',
6019       // so these types are not compatible.
6020       Diag(QuestionLoc, diag::err_cond_voidptr_arc) << LHSTy << RHSTy
6021           << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
6022       LHS = RHS = true;
6023       return QualType();
6024     }
6025     QualType lhptee = LHSTy->getAs<ObjCObjectPointerType>()->getPointeeType();
6026     QualType rhptee = RHSTy->getAs<PointerType>()->getPointeeType();
6027     QualType destPointee
6028     = Context.getQualifiedType(rhptee, lhptee.getQualifiers());
6029     QualType destType = Context.getPointerType(destPointee);
6030     // Add qualifiers if necessary.
6031     RHS = ImpCastExprToType(RHS.get(), destType, CK_NoOp);
6032     // Promote to void*.
6033     LHS = ImpCastExprToType(LHS.get(), destType, CK_BitCast);
6034     return destType;
6035   }
6036   return QualType();
6037 }
6038 
6039 /// SuggestParentheses - Emit a note with a fixit hint that wraps
6040 /// ParenRange in parentheses.
SuggestParentheses(Sema & Self,SourceLocation Loc,const PartialDiagnostic & Note,SourceRange ParenRange)6041 static void SuggestParentheses(Sema &Self, SourceLocation Loc,
6042                                const PartialDiagnostic &Note,
6043                                SourceRange ParenRange) {
6044   SourceLocation EndLoc = Self.PP.getLocForEndOfToken(ParenRange.getEnd());
6045   if (ParenRange.getBegin().isFileID() && ParenRange.getEnd().isFileID() &&
6046       EndLoc.isValid()) {
6047     Self.Diag(Loc, Note)
6048       << FixItHint::CreateInsertion(ParenRange.getBegin(), "(")
6049       << FixItHint::CreateInsertion(EndLoc, ")");
6050   } else {
6051     // We can't display the parentheses, so just show the bare note.
6052     Self.Diag(Loc, Note) << ParenRange;
6053   }
6054 }
6055 
IsArithmeticOp(BinaryOperatorKind Opc)6056 static bool IsArithmeticOp(BinaryOperatorKind Opc) {
6057   return Opc >= BO_Mul && Opc <= BO_Shr;
6058 }
6059 
6060 /// IsArithmeticBinaryExpr - Returns true if E is an arithmetic binary
6061 /// expression, either using a built-in or overloaded operator,
6062 /// and sets *OpCode to the opcode and *RHSExprs to the right-hand side
6063 /// expression.
IsArithmeticBinaryExpr(Expr * E,BinaryOperatorKind * Opcode,Expr ** RHSExprs)6064 static bool IsArithmeticBinaryExpr(Expr *E, BinaryOperatorKind *Opcode,
6065                                    Expr **RHSExprs) {
6066   // Don't strip parenthesis: we should not warn if E is in parenthesis.
6067   E = E->IgnoreImpCasts();
6068   E = E->IgnoreConversionOperator();
6069   E = E->IgnoreImpCasts();
6070 
6071   // Built-in binary operator.
6072   if (BinaryOperator *OP = dyn_cast<BinaryOperator>(E)) {
6073     if (IsArithmeticOp(OP->getOpcode())) {
6074       *Opcode = OP->getOpcode();
6075       *RHSExprs = OP->getRHS();
6076       return true;
6077     }
6078   }
6079 
6080   // Overloaded operator.
6081   if (CXXOperatorCallExpr *Call = dyn_cast<CXXOperatorCallExpr>(E)) {
6082     if (Call->getNumArgs() != 2)
6083       return false;
6084 
6085     // Make sure this is really a binary operator that is safe to pass into
6086     // BinaryOperator::getOverloadedOpcode(), e.g. it's not a subscript op.
6087     OverloadedOperatorKind OO = Call->getOperator();
6088     if (OO < OO_Plus || OO > OO_Arrow ||
6089         OO == OO_PlusPlus || OO == OO_MinusMinus)
6090       return false;
6091 
6092     BinaryOperatorKind OpKind = BinaryOperator::getOverloadedOpcode(OO);
6093     if (IsArithmeticOp(OpKind)) {
6094       *Opcode = OpKind;
6095       *RHSExprs = Call->getArg(1);
6096       return true;
6097     }
6098   }
6099 
6100   return false;
6101 }
6102 
IsLogicOp(BinaryOperatorKind Opc)6103 static bool IsLogicOp(BinaryOperatorKind Opc) {
6104   return (Opc >= BO_LT && Opc <= BO_NE) || (Opc >= BO_LAnd && Opc <= BO_LOr);
6105 }
6106 
6107 /// ExprLooksBoolean - Returns true if E looks boolean, i.e. it has boolean type
6108 /// or is a logical expression such as (x==y) which has int type, but is
6109 /// commonly interpreted as boolean.
ExprLooksBoolean(Expr * E)6110 static bool ExprLooksBoolean(Expr *E) {
6111   E = E->IgnoreParenImpCasts();
6112 
6113   if (E->getType()->isBooleanType())
6114     return true;
6115   if (BinaryOperator *OP = dyn_cast<BinaryOperator>(E))
6116     return IsLogicOp(OP->getOpcode());
6117   if (UnaryOperator *OP = dyn_cast<UnaryOperator>(E))
6118     return OP->getOpcode() == UO_LNot;
6119 
6120   return false;
6121 }
6122 
6123 /// DiagnoseConditionalPrecedence - Emit a warning when a conditional operator
6124 /// and binary operator are mixed in a way that suggests the programmer assumed
6125 /// the conditional operator has higher precedence, for example:
6126 /// "int x = a + someBinaryCondition ? 1 : 2".
DiagnoseConditionalPrecedence(Sema & Self,SourceLocation OpLoc,Expr * Condition,Expr * LHSExpr,Expr * RHSExpr)6127 static void DiagnoseConditionalPrecedence(Sema &Self,
6128                                           SourceLocation OpLoc,
6129                                           Expr *Condition,
6130                                           Expr *LHSExpr,
6131                                           Expr *RHSExpr) {
6132   BinaryOperatorKind CondOpcode;
6133   Expr *CondRHS;
6134 
6135   if (!IsArithmeticBinaryExpr(Condition, &CondOpcode, &CondRHS))
6136     return;
6137   if (!ExprLooksBoolean(CondRHS))
6138     return;
6139 
6140   // The condition is an arithmetic binary expression, with a right-
6141   // hand side that looks boolean, so warn.
6142 
6143   Self.Diag(OpLoc, diag::warn_precedence_conditional)
6144       << Condition->getSourceRange()
6145       << BinaryOperator::getOpcodeStr(CondOpcode);
6146 
6147   SuggestParentheses(Self, OpLoc,
6148     Self.PDiag(diag::note_precedence_silence)
6149       << BinaryOperator::getOpcodeStr(CondOpcode),
6150     SourceRange(Condition->getLocStart(), Condition->getLocEnd()));
6151 
6152   SuggestParentheses(Self, OpLoc,
6153     Self.PDiag(diag::note_precedence_conditional_first),
6154     SourceRange(CondRHS->getLocStart(), RHSExpr->getLocEnd()));
6155 }
6156 
6157 /// ActOnConditionalOp - Parse a ?: operation.  Note that 'LHS' may be null
6158 /// in the case of a the GNU conditional expr extension.
ActOnConditionalOp(SourceLocation QuestionLoc,SourceLocation ColonLoc,Expr * CondExpr,Expr * LHSExpr,Expr * RHSExpr)6159 ExprResult Sema::ActOnConditionalOp(SourceLocation QuestionLoc,
6160                                     SourceLocation ColonLoc,
6161                                     Expr *CondExpr, Expr *LHSExpr,
6162                                     Expr *RHSExpr) {
6163   if (!getLangOpts().CPlusPlus) {
6164     // C cannot handle TypoExpr nodes in the condition because it
6165     // doesn't handle dependent types properly, so make sure any TypoExprs have
6166     // been dealt with before checking the operands.
6167     ExprResult CondResult = CorrectDelayedTyposInExpr(CondExpr);
6168     if (!CondResult.isUsable()) return ExprError();
6169     CondExpr = CondResult.get();
6170   }
6171 
6172   // If this is the gnu "x ?: y" extension, analyze the types as though the LHS
6173   // was the condition.
6174   OpaqueValueExpr *opaqueValue = nullptr;
6175   Expr *commonExpr = nullptr;
6176   if (!LHSExpr) {
6177     commonExpr = CondExpr;
6178     // Lower out placeholder types first.  This is important so that we don't
6179     // try to capture a placeholder. This happens in few cases in C++; such
6180     // as Objective-C++'s dictionary subscripting syntax.
6181     if (commonExpr->hasPlaceholderType()) {
6182       ExprResult result = CheckPlaceholderExpr(commonExpr);
6183       if (!result.isUsable()) return ExprError();
6184       commonExpr = result.get();
6185     }
6186     // We usually want to apply unary conversions *before* saving, except
6187     // in the special case of a C++ l-value conditional.
6188     if (!(getLangOpts().CPlusPlus
6189           && !commonExpr->isTypeDependent()
6190           && commonExpr->getValueKind() == RHSExpr->getValueKind()
6191           && commonExpr->isGLValue()
6192           && commonExpr->isOrdinaryOrBitFieldObject()
6193           && RHSExpr->isOrdinaryOrBitFieldObject()
6194           && Context.hasSameType(commonExpr->getType(), RHSExpr->getType()))) {
6195       ExprResult commonRes = UsualUnaryConversions(commonExpr);
6196       if (commonRes.isInvalid())
6197         return ExprError();
6198       commonExpr = commonRes.get();
6199     }
6200 
6201     opaqueValue = new (Context) OpaqueValueExpr(commonExpr->getExprLoc(),
6202                                                 commonExpr->getType(),
6203                                                 commonExpr->getValueKind(),
6204                                                 commonExpr->getObjectKind(),
6205                                                 commonExpr);
6206     LHSExpr = CondExpr = opaqueValue;
6207   }
6208 
6209   ExprValueKind VK = VK_RValue;
6210   ExprObjectKind OK = OK_Ordinary;
6211   ExprResult Cond = CondExpr, LHS = LHSExpr, RHS = RHSExpr;
6212   QualType result = CheckConditionalOperands(Cond, LHS, RHS,
6213                                              VK, OK, QuestionLoc);
6214   if (result.isNull() || Cond.isInvalid() || LHS.isInvalid() ||
6215       RHS.isInvalid())
6216     return ExprError();
6217 
6218   DiagnoseConditionalPrecedence(*this, QuestionLoc, Cond.get(), LHS.get(),
6219                                 RHS.get());
6220 
6221   if (!commonExpr)
6222     return new (Context)
6223         ConditionalOperator(Cond.get(), QuestionLoc, LHS.get(), ColonLoc,
6224                             RHS.get(), result, VK, OK);
6225 
6226   return new (Context) BinaryConditionalOperator(
6227       commonExpr, opaqueValue, Cond.get(), LHS.get(), RHS.get(), QuestionLoc,
6228       ColonLoc, result, VK, OK);
6229 }
6230 
6231 // checkPointerTypesForAssignment - This is a very tricky routine (despite
6232 // being closely modeled after the C99 spec:-). The odd characteristic of this
6233 // routine is it effectively iqnores the qualifiers on the top level pointee.
6234 // This circumvents the usual type rules specified in 6.2.7p1 & 6.7.5.[1-3].
6235 // FIXME: add a couple examples in this comment.
6236 static Sema::AssignConvertType
checkPointerTypesForAssignment(Sema & S,QualType LHSType,QualType RHSType)6237 checkPointerTypesForAssignment(Sema &S, QualType LHSType, QualType RHSType) {
6238   assert(LHSType.isCanonical() && "LHS not canonicalized!");
6239   assert(RHSType.isCanonical() && "RHS not canonicalized!");
6240 
6241   // get the "pointed to" type (ignoring qualifiers at the top level)
6242   const Type *lhptee, *rhptee;
6243   Qualifiers lhq, rhq;
6244   std::tie(lhptee, lhq) =
6245       cast<PointerType>(LHSType)->getPointeeType().split().asPair();
6246   std::tie(rhptee, rhq) =
6247       cast<PointerType>(RHSType)->getPointeeType().split().asPair();
6248 
6249   Sema::AssignConvertType ConvTy = Sema::Compatible;
6250 
6251   // C99 6.5.16.1p1: This following citation is common to constraints
6252   // 3 & 4 (below). ...and the type *pointed to* by the left has all the
6253   // qualifiers of the type *pointed to* by the right;
6254 
6255   // As a special case, 'non-__weak A *' -> 'non-__weak const *' is okay.
6256   if (lhq.getObjCLifetime() != rhq.getObjCLifetime() &&
6257       lhq.compatiblyIncludesObjCLifetime(rhq)) {
6258     // Ignore lifetime for further calculation.
6259     lhq.removeObjCLifetime();
6260     rhq.removeObjCLifetime();
6261   }
6262 
6263   if (!lhq.compatiblyIncludes(rhq)) {
6264     // Treat address-space mismatches as fatal.  TODO: address subspaces
6265     if (!lhq.isAddressSpaceSupersetOf(rhq))
6266       ConvTy = Sema::IncompatiblePointerDiscardsQualifiers;
6267 
6268     // It's okay to add or remove GC or lifetime qualifiers when converting to
6269     // and from void*.
6270     else if (lhq.withoutObjCGCAttr().withoutObjCLifetime()
6271                         .compatiblyIncludes(
6272                                 rhq.withoutObjCGCAttr().withoutObjCLifetime())
6273              && (lhptee->isVoidType() || rhptee->isVoidType()))
6274       ; // keep old
6275 
6276     // Treat lifetime mismatches as fatal.
6277     else if (lhq.getObjCLifetime() != rhq.getObjCLifetime())
6278       ConvTy = Sema::IncompatiblePointerDiscardsQualifiers;
6279 
6280     // For GCC compatibility, other qualifier mismatches are treated
6281     // as still compatible in C.
6282     else ConvTy = Sema::CompatiblePointerDiscardsQualifiers;
6283   }
6284 
6285   // C99 6.5.16.1p1 (constraint 4): If one operand is a pointer to an object or
6286   // incomplete type and the other is a pointer to a qualified or unqualified
6287   // version of void...
6288   if (lhptee->isVoidType()) {
6289     if (rhptee->isIncompleteOrObjectType())
6290       return ConvTy;
6291 
6292     // As an extension, we allow cast to/from void* to function pointer.
6293     assert(rhptee->isFunctionType());
6294     return Sema::FunctionVoidPointer;
6295   }
6296 
6297   if (rhptee->isVoidType()) {
6298     if (lhptee->isIncompleteOrObjectType())
6299       return ConvTy;
6300 
6301     // As an extension, we allow cast to/from void* to function pointer.
6302     assert(lhptee->isFunctionType());
6303     return Sema::FunctionVoidPointer;
6304   }
6305 
6306   // C99 6.5.16.1p1 (constraint 3): both operands are pointers to qualified or
6307   // unqualified versions of compatible types, ...
6308   QualType ltrans = QualType(lhptee, 0), rtrans = QualType(rhptee, 0);
6309   if (!S.Context.typesAreCompatible(ltrans, rtrans)) {
6310     // Check if the pointee types are compatible ignoring the sign.
6311     // We explicitly check for char so that we catch "char" vs
6312     // "unsigned char" on systems where "char" is unsigned.
6313     if (lhptee->isCharType())
6314       ltrans = S.Context.UnsignedCharTy;
6315     else if (lhptee->hasSignedIntegerRepresentation())
6316       ltrans = S.Context.getCorrespondingUnsignedType(ltrans);
6317 
6318     if (rhptee->isCharType())
6319       rtrans = S.Context.UnsignedCharTy;
6320     else if (rhptee->hasSignedIntegerRepresentation())
6321       rtrans = S.Context.getCorrespondingUnsignedType(rtrans);
6322 
6323     if (ltrans == rtrans) {
6324       // Types are compatible ignoring the sign. Qualifier incompatibility
6325       // takes priority over sign incompatibility because the sign
6326       // warning can be disabled.
6327       if (ConvTy != Sema::Compatible)
6328         return ConvTy;
6329 
6330       return Sema::IncompatiblePointerSign;
6331     }
6332 
6333     // If we are a multi-level pointer, it's possible that our issue is simply
6334     // one of qualification - e.g. char ** -> const char ** is not allowed. If
6335     // the eventual target type is the same and the pointers have the same
6336     // level of indirection, this must be the issue.
6337     if (isa<PointerType>(lhptee) && isa<PointerType>(rhptee)) {
6338       do {
6339         lhptee = cast<PointerType>(lhptee)->getPointeeType().getTypePtr();
6340         rhptee = cast<PointerType>(rhptee)->getPointeeType().getTypePtr();
6341       } while (isa<PointerType>(lhptee) && isa<PointerType>(rhptee));
6342 
6343       if (lhptee == rhptee)
6344         return Sema::IncompatibleNestedPointerQualifiers;
6345     }
6346 
6347     // General pointer incompatibility takes priority over qualifiers.
6348     return Sema::IncompatiblePointer;
6349   }
6350   if (!S.getLangOpts().CPlusPlus &&
6351       S.IsNoReturnConversion(ltrans, rtrans, ltrans))
6352     return Sema::IncompatiblePointer;
6353   return ConvTy;
6354 }
6355 
6356 /// checkBlockPointerTypesForAssignment - This routine determines whether two
6357 /// block pointer types are compatible or whether a block and normal pointer
6358 /// are compatible. It is more restrict than comparing two function pointer
6359 // types.
6360 static Sema::AssignConvertType
checkBlockPointerTypesForAssignment(Sema & S,QualType LHSType,QualType RHSType)6361 checkBlockPointerTypesForAssignment(Sema &S, QualType LHSType,
6362                                     QualType RHSType) {
6363   assert(LHSType.isCanonical() && "LHS not canonicalized!");
6364   assert(RHSType.isCanonical() && "RHS not canonicalized!");
6365 
6366   QualType lhptee, rhptee;
6367 
6368   // get the "pointed to" type (ignoring qualifiers at the top level)
6369   lhptee = cast<BlockPointerType>(LHSType)->getPointeeType();
6370   rhptee = cast<BlockPointerType>(RHSType)->getPointeeType();
6371 
6372   // In C++, the types have to match exactly.
6373   if (S.getLangOpts().CPlusPlus)
6374     return Sema::IncompatibleBlockPointer;
6375 
6376   Sema::AssignConvertType ConvTy = Sema::Compatible;
6377 
6378   // For blocks we enforce that qualifiers are identical.
6379   if (lhptee.getLocalQualifiers() != rhptee.getLocalQualifiers())
6380     ConvTy = Sema::CompatiblePointerDiscardsQualifiers;
6381 
6382   if (!S.Context.typesAreBlockPointerCompatible(LHSType, RHSType))
6383     return Sema::IncompatibleBlockPointer;
6384 
6385   return ConvTy;
6386 }
6387 
6388 /// checkObjCPointerTypesForAssignment - Compares two objective-c pointer types
6389 /// for assignment compatibility.
6390 static Sema::AssignConvertType
checkObjCPointerTypesForAssignment(Sema & S,QualType LHSType,QualType RHSType)6391 checkObjCPointerTypesForAssignment(Sema &S, QualType LHSType,
6392                                    QualType RHSType) {
6393   assert(LHSType.isCanonical() && "LHS was not canonicalized!");
6394   assert(RHSType.isCanonical() && "RHS was not canonicalized!");
6395 
6396   if (LHSType->isObjCBuiltinType()) {
6397     // Class is not compatible with ObjC object pointers.
6398     if (LHSType->isObjCClassType() && !RHSType->isObjCBuiltinType() &&
6399         !RHSType->isObjCQualifiedClassType())
6400       return Sema::IncompatiblePointer;
6401     return Sema::Compatible;
6402   }
6403   if (RHSType->isObjCBuiltinType()) {
6404     if (RHSType->isObjCClassType() && !LHSType->isObjCBuiltinType() &&
6405         !LHSType->isObjCQualifiedClassType())
6406       return Sema::IncompatiblePointer;
6407     return Sema::Compatible;
6408   }
6409   QualType lhptee = LHSType->getAs<ObjCObjectPointerType>()->getPointeeType();
6410   QualType rhptee = RHSType->getAs<ObjCObjectPointerType>()->getPointeeType();
6411 
6412   if (!lhptee.isAtLeastAsQualifiedAs(rhptee) &&
6413       // make an exception for id<P>
6414       !LHSType->isObjCQualifiedIdType())
6415     return Sema::CompatiblePointerDiscardsQualifiers;
6416 
6417   if (S.Context.typesAreCompatible(LHSType, RHSType))
6418     return Sema::Compatible;
6419   if (LHSType->isObjCQualifiedIdType() || RHSType->isObjCQualifiedIdType())
6420     return Sema::IncompatibleObjCQualifiedId;
6421   return Sema::IncompatiblePointer;
6422 }
6423 
6424 Sema::AssignConvertType
CheckAssignmentConstraints(SourceLocation Loc,QualType LHSType,QualType RHSType)6425 Sema::CheckAssignmentConstraints(SourceLocation Loc,
6426                                  QualType LHSType, QualType RHSType) {
6427   // Fake up an opaque expression.  We don't actually care about what
6428   // cast operations are required, so if CheckAssignmentConstraints
6429   // adds casts to this they'll be wasted, but fortunately that doesn't
6430   // usually happen on valid code.
6431   OpaqueValueExpr RHSExpr(Loc, RHSType, VK_RValue);
6432   ExprResult RHSPtr = &RHSExpr;
6433   CastKind K = CK_Invalid;
6434 
6435   return CheckAssignmentConstraints(LHSType, RHSPtr, K);
6436 }
6437 
6438 /// CheckAssignmentConstraints (C99 6.5.16) - This routine currently
6439 /// has code to accommodate several GCC extensions when type checking
6440 /// pointers. Here are some objectionable examples that GCC considers warnings:
6441 ///
6442 ///  int a, *pint;
6443 ///  short *pshort;
6444 ///  struct foo *pfoo;
6445 ///
6446 ///  pint = pshort; // warning: assignment from incompatible pointer type
6447 ///  a = pint; // warning: assignment makes integer from pointer without a cast
6448 ///  pint = a; // warning: assignment makes pointer from integer without a cast
6449 ///  pint = pfoo; // warning: assignment from incompatible pointer type
6450 ///
6451 /// As a result, the code for dealing with pointers is more complex than the
6452 /// C99 spec dictates.
6453 ///
6454 /// Sets 'Kind' for any result kind except Incompatible.
6455 Sema::AssignConvertType
CheckAssignmentConstraints(QualType LHSType,ExprResult & RHS,CastKind & Kind)6456 Sema::CheckAssignmentConstraints(QualType LHSType, ExprResult &RHS,
6457                                  CastKind &Kind) {
6458   QualType RHSType = RHS.get()->getType();
6459   QualType OrigLHSType = LHSType;
6460 
6461   // Get canonical types.  We're not formatting these types, just comparing
6462   // them.
6463   LHSType = Context.getCanonicalType(LHSType).getUnqualifiedType();
6464   RHSType = Context.getCanonicalType(RHSType).getUnqualifiedType();
6465 
6466   // Common case: no conversion required.
6467   if (LHSType == RHSType) {
6468     Kind = CK_NoOp;
6469     return Compatible;
6470   }
6471 
6472   // If we have an atomic type, try a non-atomic assignment, then just add an
6473   // atomic qualification step.
6474   if (const AtomicType *AtomicTy = dyn_cast<AtomicType>(LHSType)) {
6475     Sema::AssignConvertType result =
6476       CheckAssignmentConstraints(AtomicTy->getValueType(), RHS, Kind);
6477     if (result != Compatible)
6478       return result;
6479     if (Kind != CK_NoOp)
6480       RHS = ImpCastExprToType(RHS.get(), AtomicTy->getValueType(), Kind);
6481     Kind = CK_NonAtomicToAtomic;
6482     return Compatible;
6483   }
6484 
6485   // If the left-hand side is a reference type, then we are in a
6486   // (rare!) case where we've allowed the use of references in C,
6487   // e.g., as a parameter type in a built-in function. In this case,
6488   // just make sure that the type referenced is compatible with the
6489   // right-hand side type. The caller is responsible for adjusting
6490   // LHSType so that the resulting expression does not have reference
6491   // type.
6492   if (const ReferenceType *LHSTypeRef = LHSType->getAs<ReferenceType>()) {
6493     if (Context.typesAreCompatible(LHSTypeRef->getPointeeType(), RHSType)) {
6494       Kind = CK_LValueBitCast;
6495       return Compatible;
6496     }
6497     return Incompatible;
6498   }
6499 
6500   // Allow scalar to ExtVector assignments, and assignments of an ExtVector type
6501   // to the same ExtVector type.
6502   if (LHSType->isExtVectorType()) {
6503     if (RHSType->isExtVectorType())
6504       return Incompatible;
6505     if (RHSType->isArithmeticType()) {
6506       // CK_VectorSplat does T -> vector T, so first cast to the
6507       // element type.
6508       QualType elType = cast<ExtVectorType>(LHSType)->getElementType();
6509       if (elType != RHSType) {
6510         Kind = PrepareScalarCast(RHS, elType);
6511         RHS = ImpCastExprToType(RHS.get(), elType, Kind);
6512       }
6513       Kind = CK_VectorSplat;
6514       return Compatible;
6515     }
6516   }
6517 
6518   // Conversions to or from vector type.
6519   if (LHSType->isVectorType() || RHSType->isVectorType()) {
6520     if (LHSType->isVectorType() && RHSType->isVectorType()) {
6521       // Allow assignments of an AltiVec vector type to an equivalent GCC
6522       // vector type and vice versa
6523       if (Context.areCompatibleVectorTypes(LHSType, RHSType)) {
6524         Kind = CK_BitCast;
6525         return Compatible;
6526       }
6527 
6528       // If we are allowing lax vector conversions, and LHS and RHS are both
6529       // vectors, the total size only needs to be the same. This is a bitcast;
6530       // no bits are changed but the result type is different.
6531       if (isLaxVectorConversion(RHSType, LHSType)) {
6532         Kind = CK_BitCast;
6533         return IncompatibleVectors;
6534       }
6535     }
6536     return Incompatible;
6537   }
6538 
6539   // Arithmetic conversions.
6540   if (LHSType->isArithmeticType() && RHSType->isArithmeticType() &&
6541       !(getLangOpts().CPlusPlus && LHSType->isEnumeralType())) {
6542     Kind = PrepareScalarCast(RHS, LHSType);
6543     return Compatible;
6544   }
6545 
6546   // Conversions to normal pointers.
6547   if (const PointerType *LHSPointer = dyn_cast<PointerType>(LHSType)) {
6548     // U* -> T*
6549     if (isa<PointerType>(RHSType)) {
6550       unsigned AddrSpaceL = LHSPointer->getPointeeType().getAddressSpace();
6551       unsigned AddrSpaceR = RHSType->getPointeeType().getAddressSpace();
6552       Kind = AddrSpaceL != AddrSpaceR ? CK_AddressSpaceConversion : CK_BitCast;
6553       return checkPointerTypesForAssignment(*this, LHSType, RHSType);
6554     }
6555 
6556     // int -> T*
6557     if (RHSType->isIntegerType()) {
6558       Kind = CK_IntegralToPointer; // FIXME: null?
6559       return IntToPointer;
6560     }
6561 
6562     // C pointers are not compatible with ObjC object pointers,
6563     // with two exceptions:
6564     if (isa<ObjCObjectPointerType>(RHSType)) {
6565       //  - conversions to void*
6566       if (LHSPointer->getPointeeType()->isVoidType()) {
6567         Kind = CK_BitCast;
6568         return Compatible;
6569       }
6570 
6571       //  - conversions from 'Class' to the redefinition type
6572       if (RHSType->isObjCClassType() &&
6573           Context.hasSameType(LHSType,
6574                               Context.getObjCClassRedefinitionType())) {
6575         Kind = CK_BitCast;
6576         return Compatible;
6577       }
6578 
6579       Kind = CK_BitCast;
6580       return IncompatiblePointer;
6581     }
6582 
6583     // U^ -> void*
6584     if (RHSType->getAs<BlockPointerType>()) {
6585       if (LHSPointer->getPointeeType()->isVoidType()) {
6586         Kind = CK_BitCast;
6587         return Compatible;
6588       }
6589     }
6590 
6591     return Incompatible;
6592   }
6593 
6594   // Conversions to block pointers.
6595   if (isa<BlockPointerType>(LHSType)) {
6596     // U^ -> T^
6597     if (RHSType->isBlockPointerType()) {
6598       Kind = CK_BitCast;
6599       return checkBlockPointerTypesForAssignment(*this, LHSType, RHSType);
6600     }
6601 
6602     // int or null -> T^
6603     if (RHSType->isIntegerType()) {
6604       Kind = CK_IntegralToPointer; // FIXME: null
6605       return IntToBlockPointer;
6606     }
6607 
6608     // id -> T^
6609     if (getLangOpts().ObjC1 && RHSType->isObjCIdType()) {
6610       Kind = CK_AnyPointerToBlockPointerCast;
6611       return Compatible;
6612     }
6613 
6614     // void* -> T^
6615     if (const PointerType *RHSPT = RHSType->getAs<PointerType>())
6616       if (RHSPT->getPointeeType()->isVoidType()) {
6617         Kind = CK_AnyPointerToBlockPointerCast;
6618         return Compatible;
6619       }
6620 
6621     return Incompatible;
6622   }
6623 
6624   // Conversions to Objective-C pointers.
6625   if (isa<ObjCObjectPointerType>(LHSType)) {
6626     // A* -> B*
6627     if (RHSType->isObjCObjectPointerType()) {
6628       Kind = CK_BitCast;
6629       Sema::AssignConvertType result =
6630         checkObjCPointerTypesForAssignment(*this, LHSType, RHSType);
6631       if (getLangOpts().ObjCAutoRefCount &&
6632           result == Compatible &&
6633           !CheckObjCARCUnavailableWeakConversion(OrigLHSType, RHSType))
6634         result = IncompatibleObjCWeakRef;
6635       return result;
6636     }
6637 
6638     // int or null -> A*
6639     if (RHSType->isIntegerType()) {
6640       Kind = CK_IntegralToPointer; // FIXME: null
6641       return IntToPointer;
6642     }
6643 
6644     // In general, C pointers are not compatible with ObjC object pointers,
6645     // with two exceptions:
6646     if (isa<PointerType>(RHSType)) {
6647       Kind = CK_CPointerToObjCPointerCast;
6648 
6649       //  - conversions from 'void*'
6650       if (RHSType->isVoidPointerType()) {
6651         return Compatible;
6652       }
6653 
6654       //  - conversions to 'Class' from its redefinition type
6655       if (LHSType->isObjCClassType() &&
6656           Context.hasSameType(RHSType,
6657                               Context.getObjCClassRedefinitionType())) {
6658         return Compatible;
6659       }
6660 
6661       return IncompatiblePointer;
6662     }
6663 
6664     // Only under strict condition T^ is compatible with an Objective-C pointer.
6665     if (RHSType->isBlockPointerType() &&
6666         isObjCPtrBlockCompatible(*this, Context, LHSType)) {
6667       maybeExtendBlockObject(*this, RHS);
6668       Kind = CK_BlockPointerToObjCPointerCast;
6669       return Compatible;
6670     }
6671 
6672     return Incompatible;
6673   }
6674 
6675   // Conversions from pointers that are not covered by the above.
6676   if (isa<PointerType>(RHSType)) {
6677     // T* -> _Bool
6678     if (LHSType == Context.BoolTy) {
6679       Kind = CK_PointerToBoolean;
6680       return Compatible;
6681     }
6682 
6683     // T* -> int
6684     if (LHSType->isIntegerType()) {
6685       Kind = CK_PointerToIntegral;
6686       return PointerToInt;
6687     }
6688 
6689     return Incompatible;
6690   }
6691 
6692   // Conversions from Objective-C pointers that are not covered by the above.
6693   if (isa<ObjCObjectPointerType>(RHSType)) {
6694     // T* -> _Bool
6695     if (LHSType == Context.BoolTy) {
6696       Kind = CK_PointerToBoolean;
6697       return Compatible;
6698     }
6699 
6700     // T* -> int
6701     if (LHSType->isIntegerType()) {
6702       Kind = CK_PointerToIntegral;
6703       return PointerToInt;
6704     }
6705 
6706     return Incompatible;
6707   }
6708 
6709   // struct A -> struct B
6710   if (isa<TagType>(LHSType) && isa<TagType>(RHSType)) {
6711     if (Context.typesAreCompatible(LHSType, RHSType)) {
6712       Kind = CK_NoOp;
6713       return Compatible;
6714     }
6715   }
6716 
6717   return Incompatible;
6718 }
6719 
6720 /// \brief Constructs a transparent union from an expression that is
6721 /// used to initialize the transparent union.
ConstructTransparentUnion(Sema & S,ASTContext & C,ExprResult & EResult,QualType UnionType,FieldDecl * Field)6722 static void ConstructTransparentUnion(Sema &S, ASTContext &C,
6723                                       ExprResult &EResult, QualType UnionType,
6724                                       FieldDecl *Field) {
6725   // Build an initializer list that designates the appropriate member
6726   // of the transparent union.
6727   Expr *E = EResult.get();
6728   InitListExpr *Initializer = new (C) InitListExpr(C, SourceLocation(),
6729                                                    E, SourceLocation());
6730   Initializer->setType(UnionType);
6731   Initializer->setInitializedFieldInUnion(Field);
6732 
6733   // Build a compound literal constructing a value of the transparent
6734   // union type from this initializer list.
6735   TypeSourceInfo *unionTInfo = C.getTrivialTypeSourceInfo(UnionType);
6736   EResult = new (C) CompoundLiteralExpr(SourceLocation(), unionTInfo, UnionType,
6737                                         VK_RValue, Initializer, false);
6738 }
6739 
6740 Sema::AssignConvertType
CheckTransparentUnionArgumentConstraints(QualType ArgType,ExprResult & RHS)6741 Sema::CheckTransparentUnionArgumentConstraints(QualType ArgType,
6742                                                ExprResult &RHS) {
6743   QualType RHSType = RHS.get()->getType();
6744 
6745   // If the ArgType is a Union type, we want to handle a potential
6746   // transparent_union GCC extension.
6747   const RecordType *UT = ArgType->getAsUnionType();
6748   if (!UT || !UT->getDecl()->hasAttr<TransparentUnionAttr>())
6749     return Incompatible;
6750 
6751   // The field to initialize within the transparent union.
6752   RecordDecl *UD = UT->getDecl();
6753   FieldDecl *InitField = nullptr;
6754   // It's compatible if the expression matches any of the fields.
6755   for (auto *it : UD->fields()) {
6756     if (it->getType()->isPointerType()) {
6757       // If the transparent union contains a pointer type, we allow:
6758       // 1) void pointer
6759       // 2) null pointer constant
6760       if (RHSType->isPointerType())
6761         if (RHSType->castAs<PointerType>()->getPointeeType()->isVoidType()) {
6762           RHS = ImpCastExprToType(RHS.get(), it->getType(), CK_BitCast);
6763           InitField = it;
6764           break;
6765         }
6766 
6767       if (RHS.get()->isNullPointerConstant(Context,
6768                                            Expr::NPC_ValueDependentIsNull)) {
6769         RHS = ImpCastExprToType(RHS.get(), it->getType(),
6770                                 CK_NullToPointer);
6771         InitField = it;
6772         break;
6773       }
6774     }
6775 
6776     CastKind Kind = CK_Invalid;
6777     if (CheckAssignmentConstraints(it->getType(), RHS, Kind)
6778           == Compatible) {
6779       RHS = ImpCastExprToType(RHS.get(), it->getType(), Kind);
6780       InitField = it;
6781       break;
6782     }
6783   }
6784 
6785   if (!InitField)
6786     return Incompatible;
6787 
6788   ConstructTransparentUnion(*this, Context, RHS, ArgType, InitField);
6789   return Compatible;
6790 }
6791 
6792 Sema::AssignConvertType
CheckSingleAssignmentConstraints(QualType LHSType,ExprResult & RHS,bool Diagnose,bool DiagnoseCFAudited)6793 Sema::CheckSingleAssignmentConstraints(QualType LHSType, ExprResult &RHS,
6794                                        bool Diagnose,
6795                                        bool DiagnoseCFAudited) {
6796   if (getLangOpts().CPlusPlus) {
6797     if (!LHSType->isRecordType() && !LHSType->isAtomicType()) {
6798       // C++ 5.17p3: If the left operand is not of class type, the
6799       // expression is implicitly converted (C++ 4) to the
6800       // cv-unqualified type of the left operand.
6801       ExprResult Res;
6802       if (Diagnose) {
6803         Res = PerformImplicitConversion(RHS.get(), LHSType.getUnqualifiedType(),
6804                                         AA_Assigning);
6805       } else {
6806         ImplicitConversionSequence ICS =
6807             TryImplicitConversion(RHS.get(), LHSType.getUnqualifiedType(),
6808                                   /*SuppressUserConversions=*/false,
6809                                   /*AllowExplicit=*/false,
6810                                   /*InOverloadResolution=*/false,
6811                                   /*CStyle=*/false,
6812                                   /*AllowObjCWritebackConversion=*/false);
6813         if (ICS.isFailure())
6814           return Incompatible;
6815         Res = PerformImplicitConversion(RHS.get(), LHSType.getUnqualifiedType(),
6816                                         ICS, AA_Assigning);
6817       }
6818       if (Res.isInvalid())
6819         return Incompatible;
6820       Sema::AssignConvertType result = Compatible;
6821       if (getLangOpts().ObjCAutoRefCount &&
6822           !CheckObjCARCUnavailableWeakConversion(LHSType,
6823                                                  RHS.get()->getType()))
6824         result = IncompatibleObjCWeakRef;
6825       RHS = Res;
6826       return result;
6827     }
6828 
6829     // FIXME: Currently, we fall through and treat C++ classes like C
6830     // structures.
6831     // FIXME: We also fall through for atomics; not sure what should
6832     // happen there, though.
6833   }
6834 
6835   // C99 6.5.16.1p1: the left operand is a pointer and the right is
6836   // a null pointer constant.
6837   if ((LHSType->isPointerType() || LHSType->isObjCObjectPointerType() ||
6838        LHSType->isBlockPointerType()) &&
6839       RHS.get()->isNullPointerConstant(Context,
6840                                        Expr::NPC_ValueDependentIsNull)) {
6841     CastKind Kind;
6842     CXXCastPath Path;
6843     CheckPointerConversion(RHS.get(), LHSType, Kind, Path, false);
6844     RHS = ImpCastExprToType(RHS.get(), LHSType, Kind, VK_RValue, &Path);
6845     return Compatible;
6846   }
6847 
6848   // This check seems unnatural, however it is necessary to ensure the proper
6849   // conversion of functions/arrays. If the conversion were done for all
6850   // DeclExpr's (created by ActOnIdExpression), it would mess up the unary
6851   // expressions that suppress this implicit conversion (&, sizeof).
6852   //
6853   // Suppress this for references: C++ 8.5.3p5.
6854   if (!LHSType->isReferenceType()) {
6855     RHS = DefaultFunctionArrayLvalueConversion(RHS.get());
6856     if (RHS.isInvalid())
6857       return Incompatible;
6858   }
6859 
6860   Expr *PRE = RHS.get()->IgnoreParenCasts();
6861   if (ObjCProtocolExpr *OPE = dyn_cast<ObjCProtocolExpr>(PRE)) {
6862     ObjCProtocolDecl *PDecl = OPE->getProtocol();
6863     if (PDecl && !PDecl->hasDefinition()) {
6864       Diag(PRE->getExprLoc(), diag::warn_atprotocol_protocol) << PDecl->getName();
6865       Diag(PDecl->getLocation(), diag::note_entity_declared_at) << PDecl;
6866     }
6867   }
6868 
6869   CastKind Kind = CK_Invalid;
6870   Sema::AssignConvertType result =
6871     CheckAssignmentConstraints(LHSType, RHS, Kind);
6872 
6873   // C99 6.5.16.1p2: The value of the right operand is converted to the
6874   // type of the assignment expression.
6875   // CheckAssignmentConstraints allows the left-hand side to be a reference,
6876   // so that we can use references in built-in functions even in C.
6877   // The getNonReferenceType() call makes sure that the resulting expression
6878   // does not have reference type.
6879   if (result != Incompatible && RHS.get()->getType() != LHSType) {
6880     QualType Ty = LHSType.getNonLValueExprType(Context);
6881     Expr *E = RHS.get();
6882     if (getLangOpts().ObjCAutoRefCount)
6883       CheckObjCARCConversion(SourceRange(), Ty, E, CCK_ImplicitConversion,
6884                              DiagnoseCFAudited);
6885     if (getLangOpts().ObjC1 &&
6886         (CheckObjCBridgeRelatedConversions(E->getLocStart(),
6887                                           LHSType, E->getType(), E) ||
6888          ConversionToObjCStringLiteralCheck(LHSType, E))) {
6889       RHS = E;
6890       return Compatible;
6891     }
6892 
6893     RHS = ImpCastExprToType(E, Ty, Kind);
6894   }
6895   return result;
6896 }
6897 
InvalidOperands(SourceLocation Loc,ExprResult & LHS,ExprResult & RHS)6898 QualType Sema::InvalidOperands(SourceLocation Loc, ExprResult &LHS,
6899                                ExprResult &RHS) {
6900   Diag(Loc, diag::err_typecheck_invalid_operands)
6901     << LHS.get()->getType() << RHS.get()->getType()
6902     << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
6903   return QualType();
6904 }
6905 
6906 /// Try to convert a value of non-vector type to a vector type by converting
6907 /// the type to the element type of the vector and then performing a splat.
6908 /// If the language is OpenCL, we only use conversions that promote scalar
6909 /// rank; for C, Obj-C, and C++ we allow any real scalar conversion except
6910 /// for float->int.
6911 ///
6912 /// \param scalar - if non-null, actually perform the conversions
6913 /// \return true if the operation fails (but without diagnosing the failure)
tryVectorConvertAndSplat(Sema & S,ExprResult * scalar,QualType scalarTy,QualType vectorEltTy,QualType vectorTy)6914 static bool tryVectorConvertAndSplat(Sema &S, ExprResult *scalar,
6915                                      QualType scalarTy,
6916                                      QualType vectorEltTy,
6917                                      QualType vectorTy) {
6918   // The conversion to apply to the scalar before splatting it,
6919   // if necessary.
6920   CastKind scalarCast = CK_Invalid;
6921 
6922   if (vectorEltTy->isIntegralType(S.Context)) {
6923     if (!scalarTy->isIntegralType(S.Context))
6924       return true;
6925     if (S.getLangOpts().OpenCL &&
6926         S.Context.getIntegerTypeOrder(vectorEltTy, scalarTy) < 0)
6927       return true;
6928     scalarCast = CK_IntegralCast;
6929   } else if (vectorEltTy->isRealFloatingType()) {
6930     if (scalarTy->isRealFloatingType()) {
6931       if (S.getLangOpts().OpenCL &&
6932           S.Context.getFloatingTypeOrder(vectorEltTy, scalarTy) < 0)
6933         return true;
6934       scalarCast = CK_FloatingCast;
6935     }
6936     else if (scalarTy->isIntegralType(S.Context))
6937       scalarCast = CK_IntegralToFloating;
6938     else
6939       return true;
6940   } else {
6941     return true;
6942   }
6943 
6944   // Adjust scalar if desired.
6945   if (scalar) {
6946     if (scalarCast != CK_Invalid)
6947       *scalar = S.ImpCastExprToType(scalar->get(), vectorEltTy, scalarCast);
6948     *scalar = S.ImpCastExprToType(scalar->get(), vectorTy, CK_VectorSplat);
6949   }
6950   return false;
6951 }
6952 
CheckVectorOperands(ExprResult & LHS,ExprResult & RHS,SourceLocation Loc,bool IsCompAssign)6953 QualType Sema::CheckVectorOperands(ExprResult &LHS, ExprResult &RHS,
6954                                    SourceLocation Loc, bool IsCompAssign) {
6955   if (!IsCompAssign) {
6956     LHS = DefaultFunctionArrayLvalueConversion(LHS.get());
6957     if (LHS.isInvalid())
6958       return QualType();
6959   }
6960   RHS = DefaultFunctionArrayLvalueConversion(RHS.get());
6961   if (RHS.isInvalid())
6962     return QualType();
6963 
6964   // For conversion purposes, we ignore any qualifiers.
6965   // For example, "const float" and "float" are equivalent.
6966   QualType LHSType = LHS.get()->getType().getUnqualifiedType();
6967   QualType RHSType = RHS.get()->getType().getUnqualifiedType();
6968 
6969   // If the vector types are identical, return.
6970   if (Context.hasSameType(LHSType, RHSType))
6971     return LHSType;
6972 
6973   const VectorType *LHSVecType = LHSType->getAs<VectorType>();
6974   const VectorType *RHSVecType = RHSType->getAs<VectorType>();
6975   assert(LHSVecType || RHSVecType);
6976 
6977   // If we have compatible AltiVec and GCC vector types, use the AltiVec type.
6978   if (LHSVecType && RHSVecType &&
6979       Context.areCompatibleVectorTypes(LHSType, RHSType)) {
6980     if (isa<ExtVectorType>(LHSVecType)) {
6981       RHS = ImpCastExprToType(RHS.get(), LHSType, CK_BitCast);
6982       return LHSType;
6983     }
6984 
6985     if (!IsCompAssign)
6986       LHS = ImpCastExprToType(LHS.get(), RHSType, CK_BitCast);
6987     return RHSType;
6988   }
6989 
6990   // If there's an ext-vector type and a scalar, try to convert the scalar to
6991   // the vector element type and splat.
6992   if (!RHSVecType && isa<ExtVectorType>(LHSVecType)) {
6993     if (!tryVectorConvertAndSplat(*this, &RHS, RHSType,
6994                                   LHSVecType->getElementType(), LHSType))
6995       return LHSType;
6996   }
6997   if (!LHSVecType && isa<ExtVectorType>(RHSVecType)) {
6998     if (!tryVectorConvertAndSplat(*this, (IsCompAssign ? nullptr : &LHS),
6999                                   LHSType, RHSVecType->getElementType(),
7000                                   RHSType))
7001       return RHSType;
7002   }
7003 
7004   // If we're allowing lax vector conversions, only the total (data) size
7005   // needs to be the same.
7006   // FIXME: Should we really be allowing this?
7007   // FIXME: We really just pick the LHS type arbitrarily?
7008   if (isLaxVectorConversion(RHSType, LHSType)) {
7009     QualType resultType = LHSType;
7010     RHS = ImpCastExprToType(RHS.get(), resultType, CK_BitCast);
7011     return resultType;
7012   }
7013 
7014   // Okay, the expression is invalid.
7015 
7016   // If there's a non-vector, non-real operand, diagnose that.
7017   if ((!RHSVecType && !RHSType->isRealType()) ||
7018       (!LHSVecType && !LHSType->isRealType())) {
7019     Diag(Loc, diag::err_typecheck_vector_not_convertable_non_scalar)
7020       << LHSType << RHSType
7021       << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
7022     return QualType();
7023   }
7024 
7025   // Otherwise, use the generic diagnostic.
7026   Diag(Loc, diag::err_typecheck_vector_not_convertable)
7027     << LHSType << RHSType
7028     << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
7029   return QualType();
7030 }
7031 
7032 // checkArithmeticNull - Detect when a NULL constant is used improperly in an
7033 // expression.  These are mainly cases where the null pointer is used as an
7034 // integer instead of a pointer.
checkArithmeticNull(Sema & S,ExprResult & LHS,ExprResult & RHS,SourceLocation Loc,bool IsCompare)7035 static void checkArithmeticNull(Sema &S, ExprResult &LHS, ExprResult &RHS,
7036                                 SourceLocation Loc, bool IsCompare) {
7037   // The canonical way to check for a GNU null is with isNullPointerConstant,
7038   // but we use a bit of a hack here for speed; this is a relatively
7039   // hot path, and isNullPointerConstant is slow.
7040   bool LHSNull = isa<GNUNullExpr>(LHS.get()->IgnoreParenImpCasts());
7041   bool RHSNull = isa<GNUNullExpr>(RHS.get()->IgnoreParenImpCasts());
7042 
7043   QualType NonNullType = LHSNull ? RHS.get()->getType() : LHS.get()->getType();
7044 
7045   // Avoid analyzing cases where the result will either be invalid (and
7046   // diagnosed as such) or entirely valid and not something to warn about.
7047   if ((!LHSNull && !RHSNull) || NonNullType->isBlockPointerType() ||
7048       NonNullType->isMemberPointerType() || NonNullType->isFunctionType())
7049     return;
7050 
7051   // Comparison operations would not make sense with a null pointer no matter
7052   // what the other expression is.
7053   if (!IsCompare) {
7054     S.Diag(Loc, diag::warn_null_in_arithmetic_operation)
7055         << (LHSNull ? LHS.get()->getSourceRange() : SourceRange())
7056         << (RHSNull ? RHS.get()->getSourceRange() : SourceRange());
7057     return;
7058   }
7059 
7060   // The rest of the operations only make sense with a null pointer
7061   // if the other expression is a pointer.
7062   if (LHSNull == RHSNull || NonNullType->isAnyPointerType() ||
7063       NonNullType->canDecayToPointerType())
7064     return;
7065 
7066   S.Diag(Loc, diag::warn_null_in_comparison_operation)
7067       << LHSNull /* LHS is NULL */ << NonNullType
7068       << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
7069 }
7070 
CheckMultiplyDivideOperands(ExprResult & LHS,ExprResult & RHS,SourceLocation Loc,bool IsCompAssign,bool IsDiv)7071 QualType Sema::CheckMultiplyDivideOperands(ExprResult &LHS, ExprResult &RHS,
7072                                            SourceLocation Loc,
7073                                            bool IsCompAssign, bool IsDiv) {
7074   checkArithmeticNull(*this, LHS, RHS, Loc, /*isCompare=*/false);
7075 
7076   if (LHS.get()->getType()->isVectorType() ||
7077       RHS.get()->getType()->isVectorType())
7078     return CheckVectorOperands(LHS, RHS, Loc, IsCompAssign);
7079 
7080   QualType compType = UsualArithmeticConversions(LHS, RHS, IsCompAssign);
7081   if (LHS.isInvalid() || RHS.isInvalid())
7082     return QualType();
7083 
7084 
7085   if (compType.isNull() || !compType->isArithmeticType())
7086     return InvalidOperands(Loc, LHS, RHS);
7087 
7088   // Check for division by zero.
7089   llvm::APSInt RHSValue;
7090   if (IsDiv && !RHS.get()->isValueDependent() &&
7091       RHS.get()->EvaluateAsInt(RHSValue, Context) && RHSValue == 0)
7092     DiagRuntimeBehavior(Loc, RHS.get(),
7093                         PDiag(diag::warn_division_by_zero)
7094                           << RHS.get()->getSourceRange());
7095 
7096   return compType;
7097 }
7098 
CheckRemainderOperands(ExprResult & LHS,ExprResult & RHS,SourceLocation Loc,bool IsCompAssign)7099 QualType Sema::CheckRemainderOperands(
7100   ExprResult &LHS, ExprResult &RHS, SourceLocation Loc, bool IsCompAssign) {
7101   checkArithmeticNull(*this, LHS, RHS, Loc, /*isCompare=*/false);
7102 
7103   if (LHS.get()->getType()->isVectorType() ||
7104       RHS.get()->getType()->isVectorType()) {
7105     if (LHS.get()->getType()->hasIntegerRepresentation() &&
7106         RHS.get()->getType()->hasIntegerRepresentation())
7107       return CheckVectorOperands(LHS, RHS, Loc, IsCompAssign);
7108     return InvalidOperands(Loc, LHS, RHS);
7109   }
7110 
7111   QualType compType = UsualArithmeticConversions(LHS, RHS, IsCompAssign);
7112   if (LHS.isInvalid() || RHS.isInvalid())
7113     return QualType();
7114 
7115   if (compType.isNull() || !compType->isIntegerType())
7116     return InvalidOperands(Loc, LHS, RHS);
7117 
7118   // Check for remainder by zero.
7119   llvm::APSInt RHSValue;
7120   if (!RHS.get()->isValueDependent() &&
7121       RHS.get()->EvaluateAsInt(RHSValue, Context) && RHSValue == 0)
7122     DiagRuntimeBehavior(Loc, RHS.get(),
7123                         PDiag(diag::warn_remainder_by_zero)
7124                           << RHS.get()->getSourceRange());
7125 
7126   return compType;
7127 }
7128 
7129 /// \brief Diagnose invalid arithmetic on two void pointers.
diagnoseArithmeticOnTwoVoidPointers(Sema & S,SourceLocation Loc,Expr * LHSExpr,Expr * RHSExpr)7130 static void diagnoseArithmeticOnTwoVoidPointers(Sema &S, SourceLocation Loc,
7131                                                 Expr *LHSExpr, Expr *RHSExpr) {
7132   S.Diag(Loc, S.getLangOpts().CPlusPlus
7133                 ? diag::err_typecheck_pointer_arith_void_type
7134                 : diag::ext_gnu_void_ptr)
7135     << 1 /* two pointers */ << LHSExpr->getSourceRange()
7136                             << RHSExpr->getSourceRange();
7137 }
7138 
7139 /// \brief Diagnose invalid arithmetic on a void pointer.
diagnoseArithmeticOnVoidPointer(Sema & S,SourceLocation Loc,Expr * Pointer)7140 static void diagnoseArithmeticOnVoidPointer(Sema &S, SourceLocation Loc,
7141                                             Expr *Pointer) {
7142   S.Diag(Loc, S.getLangOpts().CPlusPlus
7143                 ? diag::err_typecheck_pointer_arith_void_type
7144                 : diag::ext_gnu_void_ptr)
7145     << 0 /* one pointer */ << Pointer->getSourceRange();
7146 }
7147 
7148 /// \brief Diagnose invalid arithmetic on two function pointers.
diagnoseArithmeticOnTwoFunctionPointers(Sema & S,SourceLocation Loc,Expr * LHS,Expr * RHS)7149 static void diagnoseArithmeticOnTwoFunctionPointers(Sema &S, SourceLocation Loc,
7150                                                     Expr *LHS, Expr *RHS) {
7151   assert(LHS->getType()->isAnyPointerType());
7152   assert(RHS->getType()->isAnyPointerType());
7153   S.Diag(Loc, S.getLangOpts().CPlusPlus
7154                 ? diag::err_typecheck_pointer_arith_function_type
7155                 : diag::ext_gnu_ptr_func_arith)
7156     << 1 /* two pointers */ << LHS->getType()->getPointeeType()
7157     // We only show the second type if it differs from the first.
7158     << (unsigned)!S.Context.hasSameUnqualifiedType(LHS->getType(),
7159                                                    RHS->getType())
7160     << RHS->getType()->getPointeeType()
7161     << LHS->getSourceRange() << RHS->getSourceRange();
7162 }
7163 
7164 /// \brief Diagnose invalid arithmetic on a function pointer.
diagnoseArithmeticOnFunctionPointer(Sema & S,SourceLocation Loc,Expr * Pointer)7165 static void diagnoseArithmeticOnFunctionPointer(Sema &S, SourceLocation Loc,
7166                                                 Expr *Pointer) {
7167   assert(Pointer->getType()->isAnyPointerType());
7168   S.Diag(Loc, S.getLangOpts().CPlusPlus
7169                 ? diag::err_typecheck_pointer_arith_function_type
7170                 : diag::ext_gnu_ptr_func_arith)
7171     << 0 /* one pointer */ << Pointer->getType()->getPointeeType()
7172     << 0 /* one pointer, so only one type */
7173     << Pointer->getSourceRange();
7174 }
7175 
7176 /// \brief Emit error if Operand is incomplete pointer type
7177 ///
7178 /// \returns True if pointer has incomplete type
checkArithmeticIncompletePointerType(Sema & S,SourceLocation Loc,Expr * Operand)7179 static bool checkArithmeticIncompletePointerType(Sema &S, SourceLocation Loc,
7180                                                  Expr *Operand) {
7181   assert(Operand->getType()->isAnyPointerType() &&
7182          !Operand->getType()->isDependentType());
7183   QualType PointeeTy = Operand->getType()->getPointeeType();
7184   return S.RequireCompleteType(Loc, PointeeTy,
7185                                diag::err_typecheck_arithmetic_incomplete_type,
7186                                PointeeTy, Operand->getSourceRange());
7187 }
7188 
7189 /// \brief Check the validity of an arithmetic pointer operand.
7190 ///
7191 /// If the operand has pointer type, this code will check for pointer types
7192 /// which are invalid in arithmetic operations. These will be diagnosed
7193 /// appropriately, including whether or not the use is supported as an
7194 /// extension.
7195 ///
7196 /// \returns True when the operand is valid to use (even if as an extension).
checkArithmeticOpPointerOperand(Sema & S,SourceLocation Loc,Expr * Operand)7197 static bool checkArithmeticOpPointerOperand(Sema &S, SourceLocation Loc,
7198                                             Expr *Operand) {
7199   if (!Operand->getType()->isAnyPointerType()) return true;
7200 
7201   QualType PointeeTy = Operand->getType()->getPointeeType();
7202   if (PointeeTy->isVoidType()) {
7203     diagnoseArithmeticOnVoidPointer(S, Loc, Operand);
7204     return !S.getLangOpts().CPlusPlus;
7205   }
7206   if (PointeeTy->isFunctionType()) {
7207     diagnoseArithmeticOnFunctionPointer(S, Loc, Operand);
7208     return !S.getLangOpts().CPlusPlus;
7209   }
7210 
7211   if (checkArithmeticIncompletePointerType(S, Loc, Operand)) return false;
7212 
7213   return true;
7214 }
7215 
7216 /// \brief Check the validity of a binary arithmetic operation w.r.t. pointer
7217 /// operands.
7218 ///
7219 /// This routine will diagnose any invalid arithmetic on pointer operands much
7220 /// like \see checkArithmeticOpPointerOperand. However, it has special logic
7221 /// for emitting a single diagnostic even for operations where both LHS and RHS
7222 /// are (potentially problematic) pointers.
7223 ///
7224 /// \returns True when the operand is valid to use (even if as an extension).
checkArithmeticBinOpPointerOperands(Sema & S,SourceLocation Loc,Expr * LHSExpr,Expr * RHSExpr)7225 static bool checkArithmeticBinOpPointerOperands(Sema &S, SourceLocation Loc,
7226                                                 Expr *LHSExpr, Expr *RHSExpr) {
7227   bool isLHSPointer = LHSExpr->getType()->isAnyPointerType();
7228   bool isRHSPointer = RHSExpr->getType()->isAnyPointerType();
7229   if (!isLHSPointer && !isRHSPointer) return true;
7230 
7231   QualType LHSPointeeTy, RHSPointeeTy;
7232   if (isLHSPointer) LHSPointeeTy = LHSExpr->getType()->getPointeeType();
7233   if (isRHSPointer) RHSPointeeTy = RHSExpr->getType()->getPointeeType();
7234 
7235   // if both are pointers check if operation is valid wrt address spaces
7236   if (isLHSPointer && isRHSPointer) {
7237     const PointerType *lhsPtr = LHSExpr->getType()->getAs<PointerType>();
7238     const PointerType *rhsPtr = RHSExpr->getType()->getAs<PointerType>();
7239     if (!lhsPtr->isAddressSpaceOverlapping(*rhsPtr)) {
7240       S.Diag(Loc,
7241              diag::err_typecheck_op_on_nonoverlapping_address_space_pointers)
7242           << LHSExpr->getType() << RHSExpr->getType() << 1 /*arithmetic op*/
7243           << LHSExpr->getSourceRange() << RHSExpr->getSourceRange();
7244       return false;
7245     }
7246   }
7247 
7248   // Check for arithmetic on pointers to incomplete types.
7249   bool isLHSVoidPtr = isLHSPointer && LHSPointeeTy->isVoidType();
7250   bool isRHSVoidPtr = isRHSPointer && RHSPointeeTy->isVoidType();
7251   if (isLHSVoidPtr || isRHSVoidPtr) {
7252     if (!isRHSVoidPtr) diagnoseArithmeticOnVoidPointer(S, Loc, LHSExpr);
7253     else if (!isLHSVoidPtr) diagnoseArithmeticOnVoidPointer(S, Loc, RHSExpr);
7254     else diagnoseArithmeticOnTwoVoidPointers(S, Loc, LHSExpr, RHSExpr);
7255 
7256     return !S.getLangOpts().CPlusPlus;
7257   }
7258 
7259   bool isLHSFuncPtr = isLHSPointer && LHSPointeeTy->isFunctionType();
7260   bool isRHSFuncPtr = isRHSPointer && RHSPointeeTy->isFunctionType();
7261   if (isLHSFuncPtr || isRHSFuncPtr) {
7262     if (!isRHSFuncPtr) diagnoseArithmeticOnFunctionPointer(S, Loc, LHSExpr);
7263     else if (!isLHSFuncPtr) diagnoseArithmeticOnFunctionPointer(S, Loc,
7264                                                                 RHSExpr);
7265     else diagnoseArithmeticOnTwoFunctionPointers(S, Loc, LHSExpr, RHSExpr);
7266 
7267     return !S.getLangOpts().CPlusPlus;
7268   }
7269 
7270   if (isLHSPointer && checkArithmeticIncompletePointerType(S, Loc, LHSExpr))
7271     return false;
7272   if (isRHSPointer && checkArithmeticIncompletePointerType(S, Loc, RHSExpr))
7273     return false;
7274 
7275   return true;
7276 }
7277 
7278 /// diagnoseStringPlusInt - Emit a warning when adding an integer to a string
7279 /// literal.
diagnoseStringPlusInt(Sema & Self,SourceLocation OpLoc,Expr * LHSExpr,Expr * RHSExpr)7280 static void diagnoseStringPlusInt(Sema &Self, SourceLocation OpLoc,
7281                                   Expr *LHSExpr, Expr *RHSExpr) {
7282   StringLiteral* StrExpr = dyn_cast<StringLiteral>(LHSExpr->IgnoreImpCasts());
7283   Expr* IndexExpr = RHSExpr;
7284   if (!StrExpr) {
7285     StrExpr = dyn_cast<StringLiteral>(RHSExpr->IgnoreImpCasts());
7286     IndexExpr = LHSExpr;
7287   }
7288 
7289   bool IsStringPlusInt = StrExpr &&
7290       IndexExpr->getType()->isIntegralOrUnscopedEnumerationType();
7291   if (!IsStringPlusInt || IndexExpr->isValueDependent())
7292     return;
7293 
7294   llvm::APSInt index;
7295   if (IndexExpr->EvaluateAsInt(index, Self.getASTContext())) {
7296     unsigned StrLenWithNull = StrExpr->getLength() + 1;
7297     if (index.isNonNegative() &&
7298         index <= llvm::APSInt(llvm::APInt(index.getBitWidth(), StrLenWithNull),
7299                               index.isUnsigned()))
7300       return;
7301   }
7302 
7303   SourceRange DiagRange(LHSExpr->getLocStart(), RHSExpr->getLocEnd());
7304   Self.Diag(OpLoc, diag::warn_string_plus_int)
7305       << DiagRange << IndexExpr->IgnoreImpCasts()->getType();
7306 
7307   // Only print a fixit for "str" + int, not for int + "str".
7308   if (IndexExpr == RHSExpr) {
7309     SourceLocation EndLoc = Self.PP.getLocForEndOfToken(RHSExpr->getLocEnd());
7310     Self.Diag(OpLoc, diag::note_string_plus_scalar_silence)
7311         << FixItHint::CreateInsertion(LHSExpr->getLocStart(), "&")
7312         << FixItHint::CreateReplacement(SourceRange(OpLoc), "[")
7313         << FixItHint::CreateInsertion(EndLoc, "]");
7314   } else
7315     Self.Diag(OpLoc, diag::note_string_plus_scalar_silence);
7316 }
7317 
7318 /// \brief Emit a warning when adding a char literal to a string.
diagnoseStringPlusChar(Sema & Self,SourceLocation OpLoc,Expr * LHSExpr,Expr * RHSExpr)7319 static void diagnoseStringPlusChar(Sema &Self, SourceLocation OpLoc,
7320                                    Expr *LHSExpr, Expr *RHSExpr) {
7321   const Expr *StringRefExpr = LHSExpr;
7322   const CharacterLiteral *CharExpr =
7323       dyn_cast<CharacterLiteral>(RHSExpr->IgnoreImpCasts());
7324 
7325   if (!CharExpr) {
7326     CharExpr = dyn_cast<CharacterLiteral>(LHSExpr->IgnoreImpCasts());
7327     StringRefExpr = RHSExpr;
7328   }
7329 
7330   if (!CharExpr || !StringRefExpr)
7331     return;
7332 
7333   const QualType StringType = StringRefExpr->getType();
7334 
7335   // Return if not a PointerType.
7336   if (!StringType->isAnyPointerType())
7337     return;
7338 
7339   // Return if not a CharacterType.
7340   if (!StringType->getPointeeType()->isAnyCharacterType())
7341     return;
7342 
7343   ASTContext &Ctx = Self.getASTContext();
7344   SourceRange DiagRange(LHSExpr->getLocStart(), RHSExpr->getLocEnd());
7345 
7346   const QualType CharType = CharExpr->getType();
7347   if (!CharType->isAnyCharacterType() &&
7348       CharType->isIntegerType() &&
7349       llvm::isUIntN(Ctx.getCharWidth(), CharExpr->getValue())) {
7350     Self.Diag(OpLoc, diag::warn_string_plus_char)
7351         << DiagRange << Ctx.CharTy;
7352   } else {
7353     Self.Diag(OpLoc, diag::warn_string_plus_char)
7354         << DiagRange << CharExpr->getType();
7355   }
7356 
7357   // Only print a fixit for str + char, not for char + str.
7358   if (isa<CharacterLiteral>(RHSExpr->IgnoreImpCasts())) {
7359     SourceLocation EndLoc = Self.PP.getLocForEndOfToken(RHSExpr->getLocEnd());
7360     Self.Diag(OpLoc, diag::note_string_plus_scalar_silence)
7361         << FixItHint::CreateInsertion(LHSExpr->getLocStart(), "&")
7362         << FixItHint::CreateReplacement(SourceRange(OpLoc), "[")
7363         << FixItHint::CreateInsertion(EndLoc, "]");
7364   } else {
7365     Self.Diag(OpLoc, diag::note_string_plus_scalar_silence);
7366   }
7367 }
7368 
7369 /// \brief Emit error when two pointers are incompatible.
diagnosePointerIncompatibility(Sema & S,SourceLocation Loc,Expr * LHSExpr,Expr * RHSExpr)7370 static void diagnosePointerIncompatibility(Sema &S, SourceLocation Loc,
7371                                            Expr *LHSExpr, Expr *RHSExpr) {
7372   assert(LHSExpr->getType()->isAnyPointerType());
7373   assert(RHSExpr->getType()->isAnyPointerType());
7374   S.Diag(Loc, diag::err_typecheck_sub_ptr_compatible)
7375     << LHSExpr->getType() << RHSExpr->getType() << LHSExpr->getSourceRange()
7376     << RHSExpr->getSourceRange();
7377 }
7378 
CheckAdditionOperands(ExprResult & LHS,ExprResult & RHS,SourceLocation Loc,unsigned Opc,QualType * CompLHSTy)7379 QualType Sema::CheckAdditionOperands( // C99 6.5.6
7380     ExprResult &LHS, ExprResult &RHS, SourceLocation Loc, unsigned Opc,
7381     QualType* CompLHSTy) {
7382   checkArithmeticNull(*this, LHS, RHS, Loc, /*isCompare=*/false);
7383 
7384   if (LHS.get()->getType()->isVectorType() ||
7385       RHS.get()->getType()->isVectorType()) {
7386     QualType compType = CheckVectorOperands(LHS, RHS, Loc, CompLHSTy);
7387     if (CompLHSTy) *CompLHSTy = compType;
7388     return compType;
7389   }
7390 
7391   QualType compType = UsualArithmeticConversions(LHS, RHS, CompLHSTy);
7392   if (LHS.isInvalid() || RHS.isInvalid())
7393     return QualType();
7394 
7395   // Diagnose "string literal" '+' int and string '+' "char literal".
7396   if (Opc == BO_Add) {
7397     diagnoseStringPlusInt(*this, Loc, LHS.get(), RHS.get());
7398     diagnoseStringPlusChar(*this, Loc, LHS.get(), RHS.get());
7399   }
7400 
7401   // handle the common case first (both operands are arithmetic).
7402   if (!compType.isNull() && compType->isArithmeticType()) {
7403     if (CompLHSTy) *CompLHSTy = compType;
7404     return compType;
7405   }
7406 
7407   // Type-checking.  Ultimately the pointer's going to be in PExp;
7408   // note that we bias towards the LHS being the pointer.
7409   Expr *PExp = LHS.get(), *IExp = RHS.get();
7410 
7411   bool isObjCPointer;
7412   if (PExp->getType()->isPointerType()) {
7413     isObjCPointer = false;
7414   } else if (PExp->getType()->isObjCObjectPointerType()) {
7415     isObjCPointer = true;
7416   } else {
7417     std::swap(PExp, IExp);
7418     if (PExp->getType()->isPointerType()) {
7419       isObjCPointer = false;
7420     } else if (PExp->getType()->isObjCObjectPointerType()) {
7421       isObjCPointer = true;
7422     } else {
7423       return InvalidOperands(Loc, LHS, RHS);
7424     }
7425   }
7426   assert(PExp->getType()->isAnyPointerType());
7427 
7428   if (!IExp->getType()->isIntegerType())
7429     return InvalidOperands(Loc, LHS, RHS);
7430 
7431   if (!checkArithmeticOpPointerOperand(*this, Loc, PExp))
7432     return QualType();
7433 
7434   if (isObjCPointer && checkArithmeticOnObjCPointer(*this, Loc, PExp))
7435     return QualType();
7436 
7437   // Check array bounds for pointer arithemtic
7438   CheckArrayAccess(PExp, IExp);
7439 
7440   if (CompLHSTy) {
7441     QualType LHSTy = Context.isPromotableBitField(LHS.get());
7442     if (LHSTy.isNull()) {
7443       LHSTy = LHS.get()->getType();
7444       if (LHSTy->isPromotableIntegerType())
7445         LHSTy = Context.getPromotedIntegerType(LHSTy);
7446     }
7447     *CompLHSTy = LHSTy;
7448   }
7449 
7450   return PExp->getType();
7451 }
7452 
7453 // C99 6.5.6
CheckSubtractionOperands(ExprResult & LHS,ExprResult & RHS,SourceLocation Loc,QualType * CompLHSTy)7454 QualType Sema::CheckSubtractionOperands(ExprResult &LHS, ExprResult &RHS,
7455                                         SourceLocation Loc,
7456                                         QualType* CompLHSTy) {
7457   checkArithmeticNull(*this, LHS, RHS, Loc, /*isCompare=*/false);
7458 
7459   if (LHS.get()->getType()->isVectorType() ||
7460       RHS.get()->getType()->isVectorType()) {
7461     QualType compType = CheckVectorOperands(LHS, RHS, Loc, CompLHSTy);
7462     if (CompLHSTy) *CompLHSTy = compType;
7463     return compType;
7464   }
7465 
7466   QualType compType = UsualArithmeticConversions(LHS, RHS, CompLHSTy);
7467   if (LHS.isInvalid() || RHS.isInvalid())
7468     return QualType();
7469 
7470   // Enforce type constraints: C99 6.5.6p3.
7471 
7472   // Handle the common case first (both operands are arithmetic).
7473   if (!compType.isNull() && compType->isArithmeticType()) {
7474     if (CompLHSTy) *CompLHSTy = compType;
7475     return compType;
7476   }
7477 
7478   // Either ptr - int   or   ptr - ptr.
7479   if (LHS.get()->getType()->isAnyPointerType()) {
7480     QualType lpointee = LHS.get()->getType()->getPointeeType();
7481 
7482     // Diagnose bad cases where we step over interface counts.
7483     if (LHS.get()->getType()->isObjCObjectPointerType() &&
7484         checkArithmeticOnObjCPointer(*this, Loc, LHS.get()))
7485       return QualType();
7486 
7487     // The result type of a pointer-int computation is the pointer type.
7488     if (RHS.get()->getType()->isIntegerType()) {
7489       if (!checkArithmeticOpPointerOperand(*this, Loc, LHS.get()))
7490         return QualType();
7491 
7492       // Check array bounds for pointer arithemtic
7493       CheckArrayAccess(LHS.get(), RHS.get(), /*ArraySubscriptExpr*/nullptr,
7494                        /*AllowOnePastEnd*/true, /*IndexNegated*/true);
7495 
7496       if (CompLHSTy) *CompLHSTy = LHS.get()->getType();
7497       return LHS.get()->getType();
7498     }
7499 
7500     // Handle pointer-pointer subtractions.
7501     if (const PointerType *RHSPTy
7502           = RHS.get()->getType()->getAs<PointerType>()) {
7503       QualType rpointee = RHSPTy->getPointeeType();
7504 
7505       if (getLangOpts().CPlusPlus) {
7506         // Pointee types must be the same: C++ [expr.add]
7507         if (!Context.hasSameUnqualifiedType(lpointee, rpointee)) {
7508           diagnosePointerIncompatibility(*this, Loc, LHS.get(), RHS.get());
7509         }
7510       } else {
7511         // Pointee types must be compatible C99 6.5.6p3
7512         if (!Context.typesAreCompatible(
7513                 Context.getCanonicalType(lpointee).getUnqualifiedType(),
7514                 Context.getCanonicalType(rpointee).getUnqualifiedType())) {
7515           diagnosePointerIncompatibility(*this, Loc, LHS.get(), RHS.get());
7516           return QualType();
7517         }
7518       }
7519 
7520       if (!checkArithmeticBinOpPointerOperands(*this, Loc,
7521                                                LHS.get(), RHS.get()))
7522         return QualType();
7523 
7524       // The pointee type may have zero size.  As an extension, a structure or
7525       // union may have zero size or an array may have zero length.  In this
7526       // case subtraction does not make sense.
7527       if (!rpointee->isVoidType() && !rpointee->isFunctionType()) {
7528         CharUnits ElementSize = Context.getTypeSizeInChars(rpointee);
7529         if (ElementSize.isZero()) {
7530           Diag(Loc,diag::warn_sub_ptr_zero_size_types)
7531             << rpointee.getUnqualifiedType()
7532             << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
7533         }
7534       }
7535 
7536       if (CompLHSTy) *CompLHSTy = LHS.get()->getType();
7537       return Context.getPointerDiffType();
7538     }
7539   }
7540 
7541   return InvalidOperands(Loc, LHS, RHS);
7542 }
7543 
isScopedEnumerationType(QualType T)7544 static bool isScopedEnumerationType(QualType T) {
7545   if (const EnumType *ET = T->getAs<EnumType>())
7546     return ET->getDecl()->isScoped();
7547   return false;
7548 }
7549 
DiagnoseBadShiftValues(Sema & S,ExprResult & LHS,ExprResult & RHS,SourceLocation Loc,unsigned Opc,QualType LHSType)7550 static void DiagnoseBadShiftValues(Sema& S, ExprResult &LHS, ExprResult &RHS,
7551                                    SourceLocation Loc, unsigned Opc,
7552                                    QualType LHSType) {
7553   // OpenCL 6.3j: shift values are effectively % word size of LHS (more defined),
7554   // so skip remaining warnings as we don't want to modify values within Sema.
7555   if (S.getLangOpts().OpenCL)
7556     return;
7557 
7558   llvm::APSInt Right;
7559   // Check right/shifter operand
7560   if (RHS.get()->isValueDependent() ||
7561       !RHS.get()->isIntegerConstantExpr(Right, S.Context))
7562     return;
7563 
7564   if (Right.isNegative()) {
7565     S.DiagRuntimeBehavior(Loc, RHS.get(),
7566                           S.PDiag(diag::warn_shift_negative)
7567                             << RHS.get()->getSourceRange());
7568     return;
7569   }
7570   llvm::APInt LeftBits(Right.getBitWidth(),
7571                        S.Context.getTypeSize(LHS.get()->getType()));
7572   if (Right.uge(LeftBits)) {
7573     S.DiagRuntimeBehavior(Loc, RHS.get(),
7574                           S.PDiag(diag::warn_shift_gt_typewidth)
7575                             << RHS.get()->getSourceRange());
7576     return;
7577   }
7578   if (Opc != BO_Shl)
7579     return;
7580 
7581   // When left shifting an ICE which is signed, we can check for overflow which
7582   // according to C++ has undefined behavior ([expr.shift] 5.8/2). Unsigned
7583   // integers have defined behavior modulo one more than the maximum value
7584   // representable in the result type, so never warn for those.
7585   llvm::APSInt Left;
7586   if (LHS.get()->isValueDependent() ||
7587       !LHS.get()->isIntegerConstantExpr(Left, S.Context) ||
7588       LHSType->hasUnsignedIntegerRepresentation())
7589     return;
7590   llvm::APInt ResultBits =
7591       static_cast<llvm::APInt&>(Right) + Left.getMinSignedBits();
7592   if (LeftBits.uge(ResultBits))
7593     return;
7594   llvm::APSInt Result = Left.extend(ResultBits.getLimitedValue());
7595   Result = Result.shl(Right);
7596 
7597   // Print the bit representation of the signed integer as an unsigned
7598   // hexadecimal number.
7599   SmallString<40> HexResult;
7600   Result.toString(HexResult, 16, /*Signed =*/false, /*Literal =*/true);
7601 
7602   // If we are only missing a sign bit, this is less likely to result in actual
7603   // bugs -- if the result is cast back to an unsigned type, it will have the
7604   // expected value. Thus we place this behind a different warning that can be
7605   // turned off separately if needed.
7606   if (LeftBits == ResultBits - 1) {
7607     S.Diag(Loc, diag::warn_shift_result_sets_sign_bit)
7608         << HexResult.str() << LHSType
7609         << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
7610     return;
7611   }
7612 
7613   S.Diag(Loc, diag::warn_shift_result_gt_typewidth)
7614     << HexResult.str() << Result.getMinSignedBits() << LHSType
7615     << Left.getBitWidth() << LHS.get()->getSourceRange()
7616     << RHS.get()->getSourceRange();
7617 }
7618 
7619 // C99 6.5.7
CheckShiftOperands(ExprResult & LHS,ExprResult & RHS,SourceLocation Loc,unsigned Opc,bool IsCompAssign)7620 QualType Sema::CheckShiftOperands(ExprResult &LHS, ExprResult &RHS,
7621                                   SourceLocation Loc, unsigned Opc,
7622                                   bool IsCompAssign) {
7623   checkArithmeticNull(*this, LHS, RHS, Loc, /*isCompare=*/false);
7624 
7625   // Vector shifts promote their scalar inputs to vector type.
7626   if (LHS.get()->getType()->isVectorType() ||
7627       RHS.get()->getType()->isVectorType())
7628     return CheckVectorOperands(LHS, RHS, Loc, IsCompAssign);
7629 
7630   // Shifts don't perform usual arithmetic conversions, they just do integer
7631   // promotions on each operand. C99 6.5.7p3
7632 
7633   // For the LHS, do usual unary conversions, but then reset them away
7634   // if this is a compound assignment.
7635   ExprResult OldLHS = LHS;
7636   LHS = UsualUnaryConversions(LHS.get());
7637   if (LHS.isInvalid())
7638     return QualType();
7639   QualType LHSType = LHS.get()->getType();
7640   if (IsCompAssign) LHS = OldLHS;
7641 
7642   // The RHS is simpler.
7643   RHS = UsualUnaryConversions(RHS.get());
7644   if (RHS.isInvalid())
7645     return QualType();
7646   QualType RHSType = RHS.get()->getType();
7647 
7648   // C99 6.5.7p2: Each of the operands shall have integer type.
7649   if (!LHSType->hasIntegerRepresentation() ||
7650       !RHSType->hasIntegerRepresentation())
7651     return InvalidOperands(Loc, LHS, RHS);
7652 
7653   // C++0x: Don't allow scoped enums. FIXME: Use something better than
7654   // hasIntegerRepresentation() above instead of this.
7655   if (isScopedEnumerationType(LHSType) ||
7656       isScopedEnumerationType(RHSType)) {
7657     return InvalidOperands(Loc, LHS, RHS);
7658   }
7659   // Sanity-check shift operands
7660   DiagnoseBadShiftValues(*this, LHS, RHS, Loc, Opc, LHSType);
7661 
7662   // "The type of the result is that of the promoted left operand."
7663   return LHSType;
7664 }
7665 
IsWithinTemplateSpecialization(Decl * D)7666 static bool IsWithinTemplateSpecialization(Decl *D) {
7667   if (DeclContext *DC = D->getDeclContext()) {
7668     if (isa<ClassTemplateSpecializationDecl>(DC))
7669       return true;
7670     if (FunctionDecl *FD = dyn_cast<FunctionDecl>(DC))
7671       return FD->isFunctionTemplateSpecialization();
7672   }
7673   return false;
7674 }
7675 
7676 /// If two different enums are compared, raise a warning.
checkEnumComparison(Sema & S,SourceLocation Loc,Expr * LHS,Expr * RHS)7677 static void checkEnumComparison(Sema &S, SourceLocation Loc, Expr *LHS,
7678                                 Expr *RHS) {
7679   QualType LHSStrippedType = LHS->IgnoreParenImpCasts()->getType();
7680   QualType RHSStrippedType = RHS->IgnoreParenImpCasts()->getType();
7681 
7682   const EnumType *LHSEnumType = LHSStrippedType->getAs<EnumType>();
7683   if (!LHSEnumType)
7684     return;
7685   const EnumType *RHSEnumType = RHSStrippedType->getAs<EnumType>();
7686   if (!RHSEnumType)
7687     return;
7688 
7689   // Ignore anonymous enums.
7690   if (!LHSEnumType->getDecl()->getIdentifier())
7691     return;
7692   if (!RHSEnumType->getDecl()->getIdentifier())
7693     return;
7694 
7695   if (S.Context.hasSameUnqualifiedType(LHSStrippedType, RHSStrippedType))
7696     return;
7697 
7698   S.Diag(Loc, diag::warn_comparison_of_mixed_enum_types)
7699       << LHSStrippedType << RHSStrippedType
7700       << LHS->getSourceRange() << RHS->getSourceRange();
7701 }
7702 
7703 /// \brief Diagnose bad pointer comparisons.
diagnoseDistinctPointerComparison(Sema & S,SourceLocation Loc,ExprResult & LHS,ExprResult & RHS,bool IsError)7704 static void diagnoseDistinctPointerComparison(Sema &S, SourceLocation Loc,
7705                                               ExprResult &LHS, ExprResult &RHS,
7706                                               bool IsError) {
7707   S.Diag(Loc, IsError ? diag::err_typecheck_comparison_of_distinct_pointers
7708                       : diag::ext_typecheck_comparison_of_distinct_pointers)
7709     << LHS.get()->getType() << RHS.get()->getType()
7710     << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
7711 }
7712 
7713 /// \brief Returns false if the pointers are converted to a composite type,
7714 /// true otherwise.
convertPointersToCompositeType(Sema & S,SourceLocation Loc,ExprResult & LHS,ExprResult & RHS)7715 static bool convertPointersToCompositeType(Sema &S, SourceLocation Loc,
7716                                            ExprResult &LHS, ExprResult &RHS) {
7717   // C++ [expr.rel]p2:
7718   //   [...] Pointer conversions (4.10) and qualification
7719   //   conversions (4.4) are performed on pointer operands (or on
7720   //   a pointer operand and a null pointer constant) to bring
7721   //   them to their composite pointer type. [...]
7722   //
7723   // C++ [expr.eq]p1 uses the same notion for (in)equality
7724   // comparisons of pointers.
7725 
7726   // C++ [expr.eq]p2:
7727   //   In addition, pointers to members can be compared, or a pointer to
7728   //   member and a null pointer constant. Pointer to member conversions
7729   //   (4.11) and qualification conversions (4.4) are performed to bring
7730   //   them to a common type. If one operand is a null pointer constant,
7731   //   the common type is the type of the other operand. Otherwise, the
7732   //   common type is a pointer to member type similar (4.4) to the type
7733   //   of one of the operands, with a cv-qualification signature (4.4)
7734   //   that is the union of the cv-qualification signatures of the operand
7735   //   types.
7736 
7737   QualType LHSType = LHS.get()->getType();
7738   QualType RHSType = RHS.get()->getType();
7739   assert((LHSType->isPointerType() && RHSType->isPointerType()) ||
7740          (LHSType->isMemberPointerType() && RHSType->isMemberPointerType()));
7741 
7742   bool NonStandardCompositeType = false;
7743   bool *BoolPtr = S.isSFINAEContext() ? nullptr : &NonStandardCompositeType;
7744   QualType T = S.FindCompositePointerType(Loc, LHS, RHS, BoolPtr);
7745   if (T.isNull()) {
7746     diagnoseDistinctPointerComparison(S, Loc, LHS, RHS, /*isError*/true);
7747     return true;
7748   }
7749 
7750   if (NonStandardCompositeType)
7751     S.Diag(Loc, diag::ext_typecheck_comparison_of_distinct_pointers_nonstandard)
7752       << LHSType << RHSType << T << LHS.get()->getSourceRange()
7753       << RHS.get()->getSourceRange();
7754 
7755   LHS = S.ImpCastExprToType(LHS.get(), T, CK_BitCast);
7756   RHS = S.ImpCastExprToType(RHS.get(), T, CK_BitCast);
7757   return false;
7758 }
7759 
diagnoseFunctionPointerToVoidComparison(Sema & S,SourceLocation Loc,ExprResult & LHS,ExprResult & RHS,bool IsError)7760 static void diagnoseFunctionPointerToVoidComparison(Sema &S, SourceLocation Loc,
7761                                                     ExprResult &LHS,
7762                                                     ExprResult &RHS,
7763                                                     bool IsError) {
7764   S.Diag(Loc, IsError ? diag::err_typecheck_comparison_of_fptr_to_void
7765                       : diag::ext_typecheck_comparison_of_fptr_to_void)
7766     << LHS.get()->getType() << RHS.get()->getType()
7767     << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
7768 }
7769 
isObjCObjectLiteral(ExprResult & E)7770 static bool isObjCObjectLiteral(ExprResult &E) {
7771   switch (E.get()->IgnoreParenImpCasts()->getStmtClass()) {
7772   case Stmt::ObjCArrayLiteralClass:
7773   case Stmt::ObjCDictionaryLiteralClass:
7774   case Stmt::ObjCStringLiteralClass:
7775   case Stmt::ObjCBoxedExprClass:
7776     return true;
7777   default:
7778     // Note that ObjCBoolLiteral is NOT an object literal!
7779     return false;
7780   }
7781 }
7782 
hasIsEqualMethod(Sema & S,const Expr * LHS,const Expr * RHS)7783 static bool hasIsEqualMethod(Sema &S, const Expr *LHS, const Expr *RHS) {
7784   const ObjCObjectPointerType *Type =
7785     LHS->getType()->getAs<ObjCObjectPointerType>();
7786 
7787   // If this is not actually an Objective-C object, bail out.
7788   if (!Type)
7789     return false;
7790 
7791   // Get the LHS object's interface type.
7792   QualType InterfaceType = Type->getPointeeType();
7793   if (const ObjCObjectType *iQFaceTy =
7794       InterfaceType->getAsObjCQualifiedInterfaceType())
7795     InterfaceType = iQFaceTy->getBaseType();
7796 
7797   // If the RHS isn't an Objective-C object, bail out.
7798   if (!RHS->getType()->isObjCObjectPointerType())
7799     return false;
7800 
7801   // Try to find the -isEqual: method.
7802   Selector IsEqualSel = S.NSAPIObj->getIsEqualSelector();
7803   ObjCMethodDecl *Method = S.LookupMethodInObjectType(IsEqualSel,
7804                                                       InterfaceType,
7805                                                       /*instance=*/true);
7806   if (!Method) {
7807     if (Type->isObjCIdType()) {
7808       // For 'id', just check the global pool.
7809       Method = S.LookupInstanceMethodInGlobalPool(IsEqualSel, SourceRange(),
7810                                                   /*receiverId=*/true,
7811                                                   /*warn=*/false);
7812     } else {
7813       // Check protocols.
7814       Method = S.LookupMethodInQualifiedType(IsEqualSel, Type,
7815                                              /*instance=*/true);
7816     }
7817   }
7818 
7819   if (!Method)
7820     return false;
7821 
7822   QualType T = Method->parameters()[0]->getType();
7823   if (!T->isObjCObjectPointerType())
7824     return false;
7825 
7826   QualType R = Method->getReturnType();
7827   if (!R->isScalarType())
7828     return false;
7829 
7830   return true;
7831 }
7832 
CheckLiteralKind(Expr * FromE)7833 Sema::ObjCLiteralKind Sema::CheckLiteralKind(Expr *FromE) {
7834   FromE = FromE->IgnoreParenImpCasts();
7835   switch (FromE->getStmtClass()) {
7836     default:
7837       break;
7838     case Stmt::ObjCStringLiteralClass:
7839       // "string literal"
7840       return LK_String;
7841     case Stmt::ObjCArrayLiteralClass:
7842       // "array literal"
7843       return LK_Array;
7844     case Stmt::ObjCDictionaryLiteralClass:
7845       // "dictionary literal"
7846       return LK_Dictionary;
7847     case Stmt::BlockExprClass:
7848       return LK_Block;
7849     case Stmt::ObjCBoxedExprClass: {
7850       Expr *Inner = cast<ObjCBoxedExpr>(FromE)->getSubExpr()->IgnoreParens();
7851       switch (Inner->getStmtClass()) {
7852         case Stmt::IntegerLiteralClass:
7853         case Stmt::FloatingLiteralClass:
7854         case Stmt::CharacterLiteralClass:
7855         case Stmt::ObjCBoolLiteralExprClass:
7856         case Stmt::CXXBoolLiteralExprClass:
7857           // "numeric literal"
7858           return LK_Numeric;
7859         case Stmt::ImplicitCastExprClass: {
7860           CastKind CK = cast<CastExpr>(Inner)->getCastKind();
7861           // Boolean literals can be represented by implicit casts.
7862           if (CK == CK_IntegralToBoolean || CK == CK_IntegralCast)
7863             return LK_Numeric;
7864           break;
7865         }
7866         default:
7867           break;
7868       }
7869       return LK_Boxed;
7870     }
7871   }
7872   return LK_None;
7873 }
7874 
diagnoseObjCLiteralComparison(Sema & S,SourceLocation Loc,ExprResult & LHS,ExprResult & RHS,BinaryOperator::Opcode Opc)7875 static void diagnoseObjCLiteralComparison(Sema &S, SourceLocation Loc,
7876                                           ExprResult &LHS, ExprResult &RHS,
7877                                           BinaryOperator::Opcode Opc){
7878   Expr *Literal;
7879   Expr *Other;
7880   if (isObjCObjectLiteral(LHS)) {
7881     Literal = LHS.get();
7882     Other = RHS.get();
7883   } else {
7884     Literal = RHS.get();
7885     Other = LHS.get();
7886   }
7887 
7888   // Don't warn on comparisons against nil.
7889   Other = Other->IgnoreParenCasts();
7890   if (Other->isNullPointerConstant(S.getASTContext(),
7891                                    Expr::NPC_ValueDependentIsNotNull))
7892     return;
7893 
7894   // This should be kept in sync with warn_objc_literal_comparison.
7895   // LK_String should always be after the other literals, since it has its own
7896   // warning flag.
7897   Sema::ObjCLiteralKind LiteralKind = S.CheckLiteralKind(Literal);
7898   assert(LiteralKind != Sema::LK_Block);
7899   if (LiteralKind == Sema::LK_None) {
7900     llvm_unreachable("Unknown Objective-C object literal kind");
7901   }
7902 
7903   if (LiteralKind == Sema::LK_String)
7904     S.Diag(Loc, diag::warn_objc_string_literal_comparison)
7905       << Literal->getSourceRange();
7906   else
7907     S.Diag(Loc, diag::warn_objc_literal_comparison)
7908       << LiteralKind << Literal->getSourceRange();
7909 
7910   if (BinaryOperator::isEqualityOp(Opc) &&
7911       hasIsEqualMethod(S, LHS.get(), RHS.get())) {
7912     SourceLocation Start = LHS.get()->getLocStart();
7913     SourceLocation End = S.PP.getLocForEndOfToken(RHS.get()->getLocEnd());
7914     CharSourceRange OpRange =
7915       CharSourceRange::getCharRange(Loc, S.PP.getLocForEndOfToken(Loc));
7916 
7917     S.Diag(Loc, diag::note_objc_literal_comparison_isequal)
7918       << FixItHint::CreateInsertion(Start, Opc == BO_EQ ? "[" : "![")
7919       << FixItHint::CreateReplacement(OpRange, " isEqual:")
7920       << FixItHint::CreateInsertion(End, "]");
7921   }
7922 }
7923 
diagnoseLogicalNotOnLHSofComparison(Sema & S,ExprResult & LHS,ExprResult & RHS,SourceLocation Loc,unsigned OpaqueOpc)7924 static void diagnoseLogicalNotOnLHSofComparison(Sema &S, ExprResult &LHS,
7925                                                 ExprResult &RHS,
7926                                                 SourceLocation Loc,
7927                                                 unsigned OpaqueOpc) {
7928   // This checking requires bools.
7929   if (!S.getLangOpts().Bool) return;
7930 
7931   // Check that left hand side is !something.
7932   UnaryOperator *UO = dyn_cast<UnaryOperator>(LHS.get()->IgnoreImpCasts());
7933   if (!UO || UO->getOpcode() != UO_LNot) return;
7934 
7935   // Only check if the right hand side is non-bool arithmetic type.
7936   if (RHS.get()->getType()->isBooleanType()) return;
7937 
7938   // Make sure that the something in !something is not bool.
7939   Expr *SubExpr = UO->getSubExpr()->IgnoreImpCasts();
7940   if (SubExpr->getType()->isBooleanType()) return;
7941 
7942   // Emit warning.
7943   S.Diag(UO->getOperatorLoc(), diag::warn_logical_not_on_lhs_of_comparison)
7944       << Loc;
7945 
7946   // First note suggest !(x < y)
7947   SourceLocation FirstOpen = SubExpr->getLocStart();
7948   SourceLocation FirstClose = RHS.get()->getLocEnd();
7949   FirstClose = S.getPreprocessor().getLocForEndOfToken(FirstClose);
7950   if (FirstClose.isInvalid())
7951     FirstOpen = SourceLocation();
7952   S.Diag(UO->getOperatorLoc(), diag::note_logical_not_fix)
7953       << FixItHint::CreateInsertion(FirstOpen, "(")
7954       << FixItHint::CreateInsertion(FirstClose, ")");
7955 
7956   // Second note suggests (!x) < y
7957   SourceLocation SecondOpen = LHS.get()->getLocStart();
7958   SourceLocation SecondClose = LHS.get()->getLocEnd();
7959   SecondClose = S.getPreprocessor().getLocForEndOfToken(SecondClose);
7960   if (SecondClose.isInvalid())
7961     SecondOpen = SourceLocation();
7962   S.Diag(UO->getOperatorLoc(), diag::note_logical_not_silence_with_parens)
7963       << FixItHint::CreateInsertion(SecondOpen, "(")
7964       << FixItHint::CreateInsertion(SecondClose, ")");
7965 }
7966 
7967 // Get the decl for a simple expression: a reference to a variable,
7968 // an implicit C++ field reference, or an implicit ObjC ivar reference.
getCompareDecl(Expr * E)7969 static ValueDecl *getCompareDecl(Expr *E) {
7970   if (DeclRefExpr* DR = dyn_cast<DeclRefExpr>(E))
7971     return DR->getDecl();
7972   if (ObjCIvarRefExpr* Ivar = dyn_cast<ObjCIvarRefExpr>(E)) {
7973     if (Ivar->isFreeIvar())
7974       return Ivar->getDecl();
7975   }
7976   if (MemberExpr* Mem = dyn_cast<MemberExpr>(E)) {
7977     if (Mem->isImplicitAccess())
7978       return Mem->getMemberDecl();
7979   }
7980   return nullptr;
7981 }
7982 
7983 // C99 6.5.8, C++ [expr.rel]
CheckCompareOperands(ExprResult & LHS,ExprResult & RHS,SourceLocation Loc,unsigned OpaqueOpc,bool IsRelational)7984 QualType Sema::CheckCompareOperands(ExprResult &LHS, ExprResult &RHS,
7985                                     SourceLocation Loc, unsigned OpaqueOpc,
7986                                     bool IsRelational) {
7987   checkArithmeticNull(*this, LHS, RHS, Loc, /*isCompare=*/true);
7988 
7989   BinaryOperatorKind Opc = (BinaryOperatorKind) OpaqueOpc;
7990 
7991   // Handle vector comparisons separately.
7992   if (LHS.get()->getType()->isVectorType() ||
7993       RHS.get()->getType()->isVectorType())
7994     return CheckVectorCompareOperands(LHS, RHS, Loc, IsRelational);
7995 
7996   QualType LHSType = LHS.get()->getType();
7997   QualType RHSType = RHS.get()->getType();
7998 
7999   Expr *LHSStripped = LHS.get()->IgnoreParenImpCasts();
8000   Expr *RHSStripped = RHS.get()->IgnoreParenImpCasts();
8001 
8002   checkEnumComparison(*this, Loc, LHS.get(), RHS.get());
8003   diagnoseLogicalNotOnLHSofComparison(*this, LHS, RHS, Loc, OpaqueOpc);
8004 
8005   if (!LHSType->hasFloatingRepresentation() &&
8006       !(LHSType->isBlockPointerType() && IsRelational) &&
8007       !LHS.get()->getLocStart().isMacroID() &&
8008       !RHS.get()->getLocStart().isMacroID() &&
8009       ActiveTemplateInstantiations.empty()) {
8010     // For non-floating point types, check for self-comparisons of the form
8011     // x == x, x != x, x < x, etc.  These always evaluate to a constant, and
8012     // often indicate logic errors in the program.
8013     //
8014     // NOTE: Don't warn about comparison expressions resulting from macro
8015     // expansion. Also don't warn about comparisons which are only self
8016     // comparisons within a template specialization. The warnings should catch
8017     // obvious cases in the definition of the template anyways. The idea is to
8018     // warn when the typed comparison operator will always evaluate to the same
8019     // result.
8020     ValueDecl *DL = getCompareDecl(LHSStripped);
8021     ValueDecl *DR = getCompareDecl(RHSStripped);
8022     if (DL && DR && DL == DR && !IsWithinTemplateSpecialization(DL)) {
8023       DiagRuntimeBehavior(Loc, nullptr, PDiag(diag::warn_comparison_always)
8024                           << 0 // self-
8025                           << (Opc == BO_EQ
8026                               || Opc == BO_LE
8027                               || Opc == BO_GE));
8028     } else if (DL && DR && LHSType->isArrayType() && RHSType->isArrayType() &&
8029                !DL->getType()->isReferenceType() &&
8030                !DR->getType()->isReferenceType()) {
8031         // what is it always going to eval to?
8032         char always_evals_to;
8033         switch(Opc) {
8034         case BO_EQ: // e.g. array1 == array2
8035           always_evals_to = 0; // false
8036           break;
8037         case BO_NE: // e.g. array1 != array2
8038           always_evals_to = 1; // true
8039           break;
8040         default:
8041           // best we can say is 'a constant'
8042           always_evals_to = 2; // e.g. array1 <= array2
8043           break;
8044         }
8045         DiagRuntimeBehavior(Loc, nullptr, PDiag(diag::warn_comparison_always)
8046                             << 1 // array
8047                             << always_evals_to);
8048     }
8049 
8050     if (isa<CastExpr>(LHSStripped))
8051       LHSStripped = LHSStripped->IgnoreParenCasts();
8052     if (isa<CastExpr>(RHSStripped))
8053       RHSStripped = RHSStripped->IgnoreParenCasts();
8054 
8055     // Warn about comparisons against a string constant (unless the other
8056     // operand is null), the user probably wants strcmp.
8057     Expr *literalString = nullptr;
8058     Expr *literalStringStripped = nullptr;
8059     if ((isa<StringLiteral>(LHSStripped) || isa<ObjCEncodeExpr>(LHSStripped)) &&
8060         !RHSStripped->isNullPointerConstant(Context,
8061                                             Expr::NPC_ValueDependentIsNull)) {
8062       literalString = LHS.get();
8063       literalStringStripped = LHSStripped;
8064     } else if ((isa<StringLiteral>(RHSStripped) ||
8065                 isa<ObjCEncodeExpr>(RHSStripped)) &&
8066                !LHSStripped->isNullPointerConstant(Context,
8067                                             Expr::NPC_ValueDependentIsNull)) {
8068       literalString = RHS.get();
8069       literalStringStripped = RHSStripped;
8070     }
8071 
8072     if (literalString) {
8073       DiagRuntimeBehavior(Loc, nullptr,
8074         PDiag(diag::warn_stringcompare)
8075           << isa<ObjCEncodeExpr>(literalStringStripped)
8076           << literalString->getSourceRange());
8077     }
8078   }
8079 
8080   // C99 6.5.8p3 / C99 6.5.9p4
8081   UsualArithmeticConversions(LHS, RHS);
8082   if (LHS.isInvalid() || RHS.isInvalid())
8083     return QualType();
8084 
8085   LHSType = LHS.get()->getType();
8086   RHSType = RHS.get()->getType();
8087 
8088   // The result of comparisons is 'bool' in C++, 'int' in C.
8089   QualType ResultTy = Context.getLogicalOperationType();
8090 
8091   if (IsRelational) {
8092     if (LHSType->isRealType() && RHSType->isRealType())
8093       return ResultTy;
8094   } else {
8095     // Check for comparisons of floating point operands using != and ==.
8096     if (LHSType->hasFloatingRepresentation())
8097       CheckFloatComparison(Loc, LHS.get(), RHS.get());
8098 
8099     if (LHSType->isArithmeticType() && RHSType->isArithmeticType())
8100       return ResultTy;
8101   }
8102 
8103   const Expr::NullPointerConstantKind LHSNullKind =
8104       LHS.get()->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull);
8105   const Expr::NullPointerConstantKind RHSNullKind =
8106       RHS.get()->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull);
8107   bool LHSIsNull = LHSNullKind != Expr::NPCK_NotNull;
8108   bool RHSIsNull = RHSNullKind != Expr::NPCK_NotNull;
8109 
8110   if (!IsRelational && LHSIsNull != RHSIsNull) {
8111     bool IsEquality = Opc == BO_EQ;
8112     if (RHSIsNull)
8113       DiagnoseAlwaysNonNullPointer(LHS.get(), RHSNullKind, IsEquality,
8114                                    RHS.get()->getSourceRange());
8115     else
8116       DiagnoseAlwaysNonNullPointer(RHS.get(), LHSNullKind, IsEquality,
8117                                    LHS.get()->getSourceRange());
8118   }
8119 
8120   // All of the following pointer-related warnings are GCC extensions, except
8121   // when handling null pointer constants.
8122   if (LHSType->isPointerType() && RHSType->isPointerType()) { // C99 6.5.8p2
8123     QualType LCanPointeeTy =
8124       LHSType->castAs<PointerType>()->getPointeeType().getCanonicalType();
8125     QualType RCanPointeeTy =
8126       RHSType->castAs<PointerType>()->getPointeeType().getCanonicalType();
8127 
8128     if (getLangOpts().CPlusPlus) {
8129       if (LCanPointeeTy == RCanPointeeTy)
8130         return ResultTy;
8131       if (!IsRelational &&
8132           (LCanPointeeTy->isVoidType() || RCanPointeeTy->isVoidType())) {
8133         // Valid unless comparison between non-null pointer and function pointer
8134         // This is a gcc extension compatibility comparison.
8135         // In a SFINAE context, we treat this as a hard error to maintain
8136         // conformance with the C++ standard.
8137         if ((LCanPointeeTy->isFunctionType() || RCanPointeeTy->isFunctionType())
8138             && !LHSIsNull && !RHSIsNull) {
8139           diagnoseFunctionPointerToVoidComparison(
8140               *this, Loc, LHS, RHS, /*isError*/ (bool)isSFINAEContext());
8141 
8142           if (isSFINAEContext())
8143             return QualType();
8144 
8145           RHS = ImpCastExprToType(RHS.get(), LHSType, CK_BitCast);
8146           return ResultTy;
8147         }
8148       }
8149 
8150       if (convertPointersToCompositeType(*this, Loc, LHS, RHS))
8151         return QualType();
8152       else
8153         return ResultTy;
8154     }
8155     // C99 6.5.9p2 and C99 6.5.8p2
8156     if (Context.typesAreCompatible(LCanPointeeTy.getUnqualifiedType(),
8157                                    RCanPointeeTy.getUnqualifiedType())) {
8158       // Valid unless a relational comparison of function pointers
8159       if (IsRelational && LCanPointeeTy->isFunctionType()) {
8160         Diag(Loc, diag::ext_typecheck_ordered_comparison_of_function_pointers)
8161           << LHSType << RHSType << LHS.get()->getSourceRange()
8162           << RHS.get()->getSourceRange();
8163       }
8164     } else if (!IsRelational &&
8165                (LCanPointeeTy->isVoidType() || RCanPointeeTy->isVoidType())) {
8166       // Valid unless comparison between non-null pointer and function pointer
8167       if ((LCanPointeeTy->isFunctionType() || RCanPointeeTy->isFunctionType())
8168           && !LHSIsNull && !RHSIsNull)
8169         diagnoseFunctionPointerToVoidComparison(*this, Loc, LHS, RHS,
8170                                                 /*isError*/false);
8171     } else {
8172       // Invalid
8173       diagnoseDistinctPointerComparison(*this, Loc, LHS, RHS, /*isError*/false);
8174     }
8175     if (LCanPointeeTy != RCanPointeeTy) {
8176       const PointerType *lhsPtr = LHSType->getAs<PointerType>();
8177       if (!lhsPtr->isAddressSpaceOverlapping(*RHSType->getAs<PointerType>())) {
8178         Diag(Loc,
8179              diag::err_typecheck_op_on_nonoverlapping_address_space_pointers)
8180             << LHSType << RHSType << 0 /* comparison */
8181             << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
8182       }
8183       unsigned AddrSpaceL = LCanPointeeTy.getAddressSpace();
8184       unsigned AddrSpaceR = RCanPointeeTy.getAddressSpace();
8185       CastKind Kind = AddrSpaceL != AddrSpaceR ? CK_AddressSpaceConversion
8186                                                : CK_BitCast;
8187       if (LHSIsNull && !RHSIsNull)
8188         LHS = ImpCastExprToType(LHS.get(), RHSType, Kind);
8189       else
8190         RHS = ImpCastExprToType(RHS.get(), LHSType, Kind);
8191     }
8192     return ResultTy;
8193   }
8194 
8195   if (getLangOpts().CPlusPlus) {
8196     // Comparison of nullptr_t with itself.
8197     if (LHSType->isNullPtrType() && RHSType->isNullPtrType())
8198       return ResultTy;
8199 
8200     // Comparison of pointers with null pointer constants and equality
8201     // comparisons of member pointers to null pointer constants.
8202     if (RHSIsNull &&
8203         ((LHSType->isAnyPointerType() || LHSType->isNullPtrType()) ||
8204          (!IsRelational &&
8205           (LHSType->isMemberPointerType() || LHSType->isBlockPointerType())))) {
8206       RHS = ImpCastExprToType(RHS.get(), LHSType,
8207                         LHSType->isMemberPointerType()
8208                           ? CK_NullToMemberPointer
8209                           : CK_NullToPointer);
8210       return ResultTy;
8211     }
8212     if (LHSIsNull &&
8213         ((RHSType->isAnyPointerType() || RHSType->isNullPtrType()) ||
8214          (!IsRelational &&
8215           (RHSType->isMemberPointerType() || RHSType->isBlockPointerType())))) {
8216       LHS = ImpCastExprToType(LHS.get(), RHSType,
8217                         RHSType->isMemberPointerType()
8218                           ? CK_NullToMemberPointer
8219                           : CK_NullToPointer);
8220       return ResultTy;
8221     }
8222 
8223     // Comparison of member pointers.
8224     if (!IsRelational &&
8225         LHSType->isMemberPointerType() && RHSType->isMemberPointerType()) {
8226       if (convertPointersToCompositeType(*this, Loc, LHS, RHS))
8227         return QualType();
8228       else
8229         return ResultTy;
8230     }
8231 
8232     // Handle scoped enumeration types specifically, since they don't promote
8233     // to integers.
8234     if (LHS.get()->getType()->isEnumeralType() &&
8235         Context.hasSameUnqualifiedType(LHS.get()->getType(),
8236                                        RHS.get()->getType()))
8237       return ResultTy;
8238   }
8239 
8240   // Handle block pointer types.
8241   if (!IsRelational && LHSType->isBlockPointerType() &&
8242       RHSType->isBlockPointerType()) {
8243     QualType lpointee = LHSType->castAs<BlockPointerType>()->getPointeeType();
8244     QualType rpointee = RHSType->castAs<BlockPointerType>()->getPointeeType();
8245 
8246     if (!LHSIsNull && !RHSIsNull &&
8247         !Context.typesAreCompatible(lpointee, rpointee)) {
8248       Diag(Loc, diag::err_typecheck_comparison_of_distinct_blocks)
8249         << LHSType << RHSType << LHS.get()->getSourceRange()
8250         << RHS.get()->getSourceRange();
8251     }
8252     RHS = ImpCastExprToType(RHS.get(), LHSType, CK_BitCast);
8253     return ResultTy;
8254   }
8255 
8256   // Allow block pointers to be compared with null pointer constants.
8257   if (!IsRelational
8258       && ((LHSType->isBlockPointerType() && RHSType->isPointerType())
8259           || (LHSType->isPointerType() && RHSType->isBlockPointerType()))) {
8260     if (!LHSIsNull && !RHSIsNull) {
8261       if (!((RHSType->isPointerType() && RHSType->castAs<PointerType>()
8262              ->getPointeeType()->isVoidType())
8263             || (LHSType->isPointerType() && LHSType->castAs<PointerType>()
8264                 ->getPointeeType()->isVoidType())))
8265         Diag(Loc, diag::err_typecheck_comparison_of_distinct_blocks)
8266           << LHSType << RHSType << LHS.get()->getSourceRange()
8267           << RHS.get()->getSourceRange();
8268     }
8269     if (LHSIsNull && !RHSIsNull)
8270       LHS = ImpCastExprToType(LHS.get(), RHSType,
8271                               RHSType->isPointerType() ? CK_BitCast
8272                                 : CK_AnyPointerToBlockPointerCast);
8273     else
8274       RHS = ImpCastExprToType(RHS.get(), LHSType,
8275                               LHSType->isPointerType() ? CK_BitCast
8276                                 : CK_AnyPointerToBlockPointerCast);
8277     return ResultTy;
8278   }
8279 
8280   if (LHSType->isObjCObjectPointerType() ||
8281       RHSType->isObjCObjectPointerType()) {
8282     const PointerType *LPT = LHSType->getAs<PointerType>();
8283     const PointerType *RPT = RHSType->getAs<PointerType>();
8284     if (LPT || RPT) {
8285       bool LPtrToVoid = LPT ? LPT->getPointeeType()->isVoidType() : false;
8286       bool RPtrToVoid = RPT ? RPT->getPointeeType()->isVoidType() : false;
8287 
8288       if (!LPtrToVoid && !RPtrToVoid &&
8289           !Context.typesAreCompatible(LHSType, RHSType)) {
8290         diagnoseDistinctPointerComparison(*this, Loc, LHS, RHS,
8291                                           /*isError*/false);
8292       }
8293       if (LHSIsNull && !RHSIsNull) {
8294         Expr *E = LHS.get();
8295         if (getLangOpts().ObjCAutoRefCount)
8296           CheckObjCARCConversion(SourceRange(), RHSType, E, CCK_ImplicitConversion);
8297         LHS = ImpCastExprToType(E, RHSType,
8298                                 RPT ? CK_BitCast :CK_CPointerToObjCPointerCast);
8299       }
8300       else {
8301         Expr *E = RHS.get();
8302         if (getLangOpts().ObjCAutoRefCount)
8303           CheckObjCARCConversion(SourceRange(), LHSType, E, CCK_ImplicitConversion, false,
8304                                  Opc);
8305         RHS = ImpCastExprToType(E, LHSType,
8306                                 LPT ? CK_BitCast :CK_CPointerToObjCPointerCast);
8307       }
8308       return ResultTy;
8309     }
8310     if (LHSType->isObjCObjectPointerType() &&
8311         RHSType->isObjCObjectPointerType()) {
8312       if (!Context.areComparableObjCPointerTypes(LHSType, RHSType))
8313         diagnoseDistinctPointerComparison(*this, Loc, LHS, RHS,
8314                                           /*isError*/false);
8315       if (isObjCObjectLiteral(LHS) || isObjCObjectLiteral(RHS))
8316         diagnoseObjCLiteralComparison(*this, Loc, LHS, RHS, Opc);
8317 
8318       if (LHSIsNull && !RHSIsNull)
8319         LHS = ImpCastExprToType(LHS.get(), RHSType, CK_BitCast);
8320       else
8321         RHS = ImpCastExprToType(RHS.get(), LHSType, CK_BitCast);
8322       return ResultTy;
8323     }
8324   }
8325   if ((LHSType->isAnyPointerType() && RHSType->isIntegerType()) ||
8326       (LHSType->isIntegerType() && RHSType->isAnyPointerType())) {
8327     unsigned DiagID = 0;
8328     bool isError = false;
8329     if (LangOpts.DebuggerSupport) {
8330       // Under a debugger, allow the comparison of pointers to integers,
8331       // since users tend to want to compare addresses.
8332     } else if ((LHSIsNull && LHSType->isIntegerType()) ||
8333         (RHSIsNull && RHSType->isIntegerType())) {
8334       if (IsRelational && !getLangOpts().CPlusPlus)
8335         DiagID = diag::ext_typecheck_ordered_comparison_of_pointer_and_zero;
8336     } else if (IsRelational && !getLangOpts().CPlusPlus)
8337       DiagID = diag::ext_typecheck_ordered_comparison_of_pointer_integer;
8338     else if (getLangOpts().CPlusPlus) {
8339       DiagID = diag::err_typecheck_comparison_of_pointer_integer;
8340       isError = true;
8341     } else
8342       DiagID = diag::ext_typecheck_comparison_of_pointer_integer;
8343 
8344     if (DiagID) {
8345       Diag(Loc, DiagID)
8346         << LHSType << RHSType << LHS.get()->getSourceRange()
8347         << RHS.get()->getSourceRange();
8348       if (isError)
8349         return QualType();
8350     }
8351 
8352     if (LHSType->isIntegerType())
8353       LHS = ImpCastExprToType(LHS.get(), RHSType,
8354                         LHSIsNull ? CK_NullToPointer : CK_IntegralToPointer);
8355     else
8356       RHS = ImpCastExprToType(RHS.get(), LHSType,
8357                         RHSIsNull ? CK_NullToPointer : CK_IntegralToPointer);
8358     return ResultTy;
8359   }
8360 
8361   // Handle block pointers.
8362   if (!IsRelational && RHSIsNull
8363       && LHSType->isBlockPointerType() && RHSType->isIntegerType()) {
8364     RHS = ImpCastExprToType(RHS.get(), LHSType, CK_NullToPointer);
8365     return ResultTy;
8366   }
8367   if (!IsRelational && LHSIsNull
8368       && LHSType->isIntegerType() && RHSType->isBlockPointerType()) {
8369     LHS = ImpCastExprToType(LHS.get(), RHSType, CK_NullToPointer);
8370     return ResultTy;
8371   }
8372 
8373   return InvalidOperands(Loc, LHS, RHS);
8374 }
8375 
8376 
8377 // Return a signed type that is of identical size and number of elements.
8378 // For floating point vectors, return an integer type of identical size
8379 // and number of elements.
GetSignedVectorType(QualType V)8380 QualType Sema::GetSignedVectorType(QualType V) {
8381   const VectorType *VTy = V->getAs<VectorType>();
8382   unsigned TypeSize = Context.getTypeSize(VTy->getElementType());
8383   if (TypeSize == Context.getTypeSize(Context.CharTy))
8384     return Context.getExtVectorType(Context.CharTy, VTy->getNumElements());
8385   else if (TypeSize == Context.getTypeSize(Context.ShortTy))
8386     return Context.getExtVectorType(Context.ShortTy, VTy->getNumElements());
8387   else if (TypeSize == Context.getTypeSize(Context.IntTy))
8388     return Context.getExtVectorType(Context.IntTy, VTy->getNumElements());
8389   else if (TypeSize == Context.getTypeSize(Context.LongTy))
8390     return Context.getExtVectorType(Context.LongTy, VTy->getNumElements());
8391   assert(TypeSize == Context.getTypeSize(Context.LongLongTy) &&
8392          "Unhandled vector element size in vector compare");
8393   return Context.getExtVectorType(Context.LongLongTy, VTy->getNumElements());
8394 }
8395 
8396 /// CheckVectorCompareOperands - vector comparisons are a clang extension that
8397 /// operates on extended vector types.  Instead of producing an IntTy result,
8398 /// like a scalar comparison, a vector comparison produces a vector of integer
8399 /// types.
CheckVectorCompareOperands(ExprResult & LHS,ExprResult & RHS,SourceLocation Loc,bool IsRelational)8400 QualType Sema::CheckVectorCompareOperands(ExprResult &LHS, ExprResult &RHS,
8401                                           SourceLocation Loc,
8402                                           bool IsRelational) {
8403   // Check to make sure we're operating on vectors of the same type and width,
8404   // Allowing one side to be a scalar of element type.
8405   QualType vType = CheckVectorOperands(LHS, RHS, Loc, /*isCompAssign*/false);
8406   if (vType.isNull())
8407     return vType;
8408 
8409   QualType LHSType = LHS.get()->getType();
8410 
8411   // If AltiVec, the comparison results in a numeric type, i.e.
8412   // bool for C++, int for C
8413   if (vType->getAs<VectorType>()->getVectorKind() == VectorType::AltiVecVector)
8414     return Context.getLogicalOperationType();
8415 
8416   // For non-floating point types, check for self-comparisons of the form
8417   // x == x, x != x, x < x, etc.  These always evaluate to a constant, and
8418   // often indicate logic errors in the program.
8419   if (!LHSType->hasFloatingRepresentation() &&
8420       ActiveTemplateInstantiations.empty()) {
8421     if (DeclRefExpr* DRL
8422           = dyn_cast<DeclRefExpr>(LHS.get()->IgnoreParenImpCasts()))
8423       if (DeclRefExpr* DRR
8424             = dyn_cast<DeclRefExpr>(RHS.get()->IgnoreParenImpCasts()))
8425         if (DRL->getDecl() == DRR->getDecl())
8426           DiagRuntimeBehavior(Loc, nullptr,
8427                               PDiag(diag::warn_comparison_always)
8428                                 << 0 // self-
8429                                 << 2 // "a constant"
8430                               );
8431   }
8432 
8433   // Check for comparisons of floating point operands using != and ==.
8434   if (!IsRelational && LHSType->hasFloatingRepresentation()) {
8435     assert (RHS.get()->getType()->hasFloatingRepresentation());
8436     CheckFloatComparison(Loc, LHS.get(), RHS.get());
8437   }
8438 
8439   // Return a signed type for the vector.
8440   return GetSignedVectorType(LHSType);
8441 }
8442 
CheckVectorLogicalOperands(ExprResult & LHS,ExprResult & RHS,SourceLocation Loc)8443 QualType Sema::CheckVectorLogicalOperands(ExprResult &LHS, ExprResult &RHS,
8444                                           SourceLocation Loc) {
8445   // Ensure that either both operands are of the same vector type, or
8446   // one operand is of a vector type and the other is of its element type.
8447   QualType vType = CheckVectorOperands(LHS, RHS, Loc, false);
8448   if (vType.isNull())
8449     return InvalidOperands(Loc, LHS, RHS);
8450   if (getLangOpts().OpenCL && getLangOpts().OpenCLVersion < 120 &&
8451       vType->hasFloatingRepresentation())
8452     return InvalidOperands(Loc, LHS, RHS);
8453 
8454   return GetSignedVectorType(LHS.get()->getType());
8455 }
8456 
CheckBitwiseOperands(ExprResult & LHS,ExprResult & RHS,SourceLocation Loc,bool IsCompAssign)8457 inline QualType Sema::CheckBitwiseOperands(
8458   ExprResult &LHS, ExprResult &RHS, SourceLocation Loc, bool IsCompAssign) {
8459   checkArithmeticNull(*this, LHS, RHS, Loc, /*isCompare=*/false);
8460 
8461   if (LHS.get()->getType()->isVectorType() ||
8462       RHS.get()->getType()->isVectorType()) {
8463     if (LHS.get()->getType()->hasIntegerRepresentation() &&
8464         RHS.get()->getType()->hasIntegerRepresentation())
8465       return CheckVectorOperands(LHS, RHS, Loc, IsCompAssign);
8466 
8467     return InvalidOperands(Loc, LHS, RHS);
8468   }
8469 
8470   ExprResult LHSResult = LHS, RHSResult = RHS;
8471   QualType compType = UsualArithmeticConversions(LHSResult, RHSResult,
8472                                                  IsCompAssign);
8473   if (LHSResult.isInvalid() || RHSResult.isInvalid())
8474     return QualType();
8475   LHS = LHSResult.get();
8476   RHS = RHSResult.get();
8477 
8478   if (!compType.isNull() && compType->isIntegralOrUnscopedEnumerationType())
8479     return compType;
8480   return InvalidOperands(Loc, LHS, RHS);
8481 }
8482 
CheckLogicalOperands(ExprResult & LHS,ExprResult & RHS,SourceLocation Loc,unsigned Opc)8483 inline QualType Sema::CheckLogicalOperands( // C99 6.5.[13,14]
8484   ExprResult &LHS, ExprResult &RHS, SourceLocation Loc, unsigned Opc) {
8485 
8486   // Check vector operands differently.
8487   if (LHS.get()->getType()->isVectorType() || RHS.get()->getType()->isVectorType())
8488     return CheckVectorLogicalOperands(LHS, RHS, Loc);
8489 
8490   // Diagnose cases where the user write a logical and/or but probably meant a
8491   // bitwise one.  We do this when the LHS is a non-bool integer and the RHS
8492   // is a constant.
8493   if (LHS.get()->getType()->isIntegerType() &&
8494       !LHS.get()->getType()->isBooleanType() &&
8495       RHS.get()->getType()->isIntegerType() && !RHS.get()->isValueDependent() &&
8496       // Don't warn in macros or template instantiations.
8497       !Loc.isMacroID() && ActiveTemplateInstantiations.empty()) {
8498     // If the RHS can be constant folded, and if it constant folds to something
8499     // that isn't 0 or 1 (which indicate a potential logical operation that
8500     // happened to fold to true/false) then warn.
8501     // Parens on the RHS are ignored.
8502     llvm::APSInt Result;
8503     if (RHS.get()->EvaluateAsInt(Result, Context))
8504       if ((getLangOpts().Bool && !RHS.get()->getType()->isBooleanType() &&
8505            !RHS.get()->getExprLoc().isMacroID()) ||
8506           (Result != 0 && Result != 1)) {
8507         Diag(Loc, diag::warn_logical_instead_of_bitwise)
8508           << RHS.get()->getSourceRange()
8509           << (Opc == BO_LAnd ? "&&" : "||");
8510         // Suggest replacing the logical operator with the bitwise version
8511         Diag(Loc, diag::note_logical_instead_of_bitwise_change_operator)
8512             << (Opc == BO_LAnd ? "&" : "|")
8513             << FixItHint::CreateReplacement(SourceRange(
8514                 Loc, Lexer::getLocForEndOfToken(Loc, 0, getSourceManager(),
8515                                                 getLangOpts())),
8516                                             Opc == BO_LAnd ? "&" : "|");
8517         if (Opc == BO_LAnd)
8518           // Suggest replacing "Foo() && kNonZero" with "Foo()"
8519           Diag(Loc, diag::note_logical_instead_of_bitwise_remove_constant)
8520               << FixItHint::CreateRemoval(
8521                   SourceRange(
8522                       Lexer::getLocForEndOfToken(LHS.get()->getLocEnd(),
8523                                                  0, getSourceManager(),
8524                                                  getLangOpts()),
8525                       RHS.get()->getLocEnd()));
8526       }
8527   }
8528 
8529   if (!Context.getLangOpts().CPlusPlus) {
8530     // OpenCL v1.1 s6.3.g: The logical operators and (&&), or (||) do
8531     // not operate on the built-in scalar and vector float types.
8532     if (Context.getLangOpts().OpenCL &&
8533         Context.getLangOpts().OpenCLVersion < 120) {
8534       if (LHS.get()->getType()->isFloatingType() ||
8535           RHS.get()->getType()->isFloatingType())
8536         return InvalidOperands(Loc, LHS, RHS);
8537     }
8538 
8539     LHS = UsualUnaryConversions(LHS.get());
8540     if (LHS.isInvalid())
8541       return QualType();
8542 
8543     RHS = UsualUnaryConversions(RHS.get());
8544     if (RHS.isInvalid())
8545       return QualType();
8546 
8547     if (!LHS.get()->getType()->isScalarType() ||
8548         !RHS.get()->getType()->isScalarType())
8549       return InvalidOperands(Loc, LHS, RHS);
8550 
8551     return Context.IntTy;
8552   }
8553 
8554   // The following is safe because we only use this method for
8555   // non-overloadable operands.
8556 
8557   // C++ [expr.log.and]p1
8558   // C++ [expr.log.or]p1
8559   // The operands are both contextually converted to type bool.
8560   ExprResult LHSRes = PerformContextuallyConvertToBool(LHS.get());
8561   if (LHSRes.isInvalid())
8562     return InvalidOperands(Loc, LHS, RHS);
8563   LHS = LHSRes;
8564 
8565   ExprResult RHSRes = PerformContextuallyConvertToBool(RHS.get());
8566   if (RHSRes.isInvalid())
8567     return InvalidOperands(Loc, LHS, RHS);
8568   RHS = RHSRes;
8569 
8570   // C++ [expr.log.and]p2
8571   // C++ [expr.log.or]p2
8572   // The result is a bool.
8573   return Context.BoolTy;
8574 }
8575 
IsReadonlyMessage(Expr * E,Sema & S)8576 static bool IsReadonlyMessage(Expr *E, Sema &S) {
8577   const MemberExpr *ME = dyn_cast<MemberExpr>(E);
8578   if (!ME) return false;
8579   if (!isa<FieldDecl>(ME->getMemberDecl())) return false;
8580   ObjCMessageExpr *Base =
8581     dyn_cast<ObjCMessageExpr>(ME->getBase()->IgnoreParenImpCasts());
8582   if (!Base) return false;
8583   return Base->getMethodDecl() != nullptr;
8584 }
8585 
8586 /// Is the given expression (which must be 'const') a reference to a
8587 /// variable which was originally non-const, but which has become
8588 /// 'const' due to being captured within a block?
8589 enum NonConstCaptureKind { NCCK_None, NCCK_Block, NCCK_Lambda };
isReferenceToNonConstCapture(Sema & S,Expr * E)8590 static NonConstCaptureKind isReferenceToNonConstCapture(Sema &S, Expr *E) {
8591   assert(E->isLValue() && E->getType().isConstQualified());
8592   E = E->IgnoreParens();
8593 
8594   // Must be a reference to a declaration from an enclosing scope.
8595   DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E);
8596   if (!DRE) return NCCK_None;
8597   if (!DRE->refersToEnclosingVariableOrCapture()) return NCCK_None;
8598 
8599   // The declaration must be a variable which is not declared 'const'.
8600   VarDecl *var = dyn_cast<VarDecl>(DRE->getDecl());
8601   if (!var) return NCCK_None;
8602   if (var->getType().isConstQualified()) return NCCK_None;
8603   assert(var->hasLocalStorage() && "capture added 'const' to non-local?");
8604 
8605   // Decide whether the first capture was for a block or a lambda.
8606   DeclContext *DC = S.CurContext, *Prev = nullptr;
8607   while (DC != var->getDeclContext()) {
8608     Prev = DC;
8609     DC = DC->getParent();
8610   }
8611   // Unless we have an init-capture, we've gone one step too far.
8612   if (!var->isInitCapture())
8613     DC = Prev;
8614   return (isa<BlockDecl>(DC) ? NCCK_Block : NCCK_Lambda);
8615 }
8616 
8617 /// CheckForModifiableLvalue - Verify that E is a modifiable lvalue.  If not,
8618 /// emit an error and return true.  If so, return false.
CheckForModifiableLvalue(Expr * E,SourceLocation Loc,Sema & S)8619 static bool CheckForModifiableLvalue(Expr *E, SourceLocation Loc, Sema &S) {
8620   assert(!E->hasPlaceholderType(BuiltinType::PseudoObject));
8621   SourceLocation OrigLoc = Loc;
8622   Expr::isModifiableLvalueResult IsLV = E->isModifiableLvalue(S.Context,
8623                                                               &Loc);
8624   if (IsLV == Expr::MLV_ClassTemporary && IsReadonlyMessage(E, S))
8625     IsLV = Expr::MLV_InvalidMessageExpression;
8626   if (IsLV == Expr::MLV_Valid)
8627     return false;
8628 
8629   unsigned DiagID = 0;
8630   bool NeedType = false;
8631   switch (IsLV) { // C99 6.5.16p2
8632   case Expr::MLV_ConstQualified:
8633     DiagID = diag::err_typecheck_assign_const;
8634 
8635     // Use a specialized diagnostic when we're assigning to an object
8636     // from an enclosing function or block.
8637     if (NonConstCaptureKind NCCK = isReferenceToNonConstCapture(S, E)) {
8638       if (NCCK == NCCK_Block)
8639         DiagID = diag::err_block_decl_ref_not_modifiable_lvalue;
8640       else
8641         DiagID = diag::err_lambda_decl_ref_not_modifiable_lvalue;
8642       break;
8643     }
8644 
8645     // In ARC, use some specialized diagnostics for occasions where we
8646     // infer 'const'.  These are always pseudo-strong variables.
8647     if (S.getLangOpts().ObjCAutoRefCount) {
8648       DeclRefExpr *declRef = dyn_cast<DeclRefExpr>(E->IgnoreParenCasts());
8649       if (declRef && isa<VarDecl>(declRef->getDecl())) {
8650         VarDecl *var = cast<VarDecl>(declRef->getDecl());
8651 
8652         // Use the normal diagnostic if it's pseudo-__strong but the
8653         // user actually wrote 'const'.
8654         if (var->isARCPseudoStrong() &&
8655             (!var->getTypeSourceInfo() ||
8656              !var->getTypeSourceInfo()->getType().isConstQualified())) {
8657           // There are two pseudo-strong cases:
8658           //  - self
8659           ObjCMethodDecl *method = S.getCurMethodDecl();
8660           if (method && var == method->getSelfDecl())
8661             DiagID = method->isClassMethod()
8662               ? diag::err_typecheck_arc_assign_self_class_method
8663               : diag::err_typecheck_arc_assign_self;
8664 
8665           //  - fast enumeration variables
8666           else
8667             DiagID = diag::err_typecheck_arr_assign_enumeration;
8668 
8669           SourceRange Assign;
8670           if (Loc != OrigLoc)
8671             Assign = SourceRange(OrigLoc, OrigLoc);
8672           S.Diag(Loc, DiagID) << E->getSourceRange() << Assign;
8673           // We need to preserve the AST regardless, so migration tool
8674           // can do its job.
8675           return false;
8676         }
8677       }
8678     }
8679 
8680     break;
8681   case Expr::MLV_ArrayType:
8682   case Expr::MLV_ArrayTemporary:
8683     DiagID = diag::err_typecheck_array_not_modifiable_lvalue;
8684     NeedType = true;
8685     break;
8686   case Expr::MLV_NotObjectType:
8687     DiagID = diag::err_typecheck_non_object_not_modifiable_lvalue;
8688     NeedType = true;
8689     break;
8690   case Expr::MLV_LValueCast:
8691     DiagID = diag::err_typecheck_lvalue_casts_not_supported;
8692     break;
8693   case Expr::MLV_Valid:
8694     llvm_unreachable("did not take early return for MLV_Valid");
8695   case Expr::MLV_InvalidExpression:
8696   case Expr::MLV_MemberFunction:
8697   case Expr::MLV_ClassTemporary:
8698     DiagID = diag::err_typecheck_expression_not_modifiable_lvalue;
8699     break;
8700   case Expr::MLV_IncompleteType:
8701   case Expr::MLV_IncompleteVoidType:
8702     return S.RequireCompleteType(Loc, E->getType(),
8703              diag::err_typecheck_incomplete_type_not_modifiable_lvalue, E);
8704   case Expr::MLV_DuplicateVectorComponents:
8705     DiagID = diag::err_typecheck_duplicate_vector_components_not_mlvalue;
8706     break;
8707   case Expr::MLV_NoSetterProperty:
8708     llvm_unreachable("readonly properties should be processed differently");
8709   case Expr::MLV_InvalidMessageExpression:
8710     DiagID = diag::error_readonly_message_assignment;
8711     break;
8712   case Expr::MLV_SubObjCPropertySetting:
8713     DiagID = diag::error_no_subobject_property_setting;
8714     break;
8715   }
8716 
8717   SourceRange Assign;
8718   if (Loc != OrigLoc)
8719     Assign = SourceRange(OrigLoc, OrigLoc);
8720   if (NeedType)
8721     S.Diag(Loc, DiagID) << E->getType() << E->getSourceRange() << Assign;
8722   else
8723     S.Diag(Loc, DiagID) << E->getSourceRange() << Assign;
8724   return true;
8725 }
8726 
CheckIdentityFieldAssignment(Expr * LHSExpr,Expr * RHSExpr,SourceLocation Loc,Sema & Sema)8727 static void CheckIdentityFieldAssignment(Expr *LHSExpr, Expr *RHSExpr,
8728                                          SourceLocation Loc,
8729                                          Sema &Sema) {
8730   // C / C++ fields
8731   MemberExpr *ML = dyn_cast<MemberExpr>(LHSExpr);
8732   MemberExpr *MR = dyn_cast<MemberExpr>(RHSExpr);
8733   if (ML && MR && ML->getMemberDecl() == MR->getMemberDecl()) {
8734     if (isa<CXXThisExpr>(ML->getBase()) && isa<CXXThisExpr>(MR->getBase()))
8735       Sema.Diag(Loc, diag::warn_identity_field_assign) << 0;
8736   }
8737 
8738   // Objective-C instance variables
8739   ObjCIvarRefExpr *OL = dyn_cast<ObjCIvarRefExpr>(LHSExpr);
8740   ObjCIvarRefExpr *OR = dyn_cast<ObjCIvarRefExpr>(RHSExpr);
8741   if (OL && OR && OL->getDecl() == OR->getDecl()) {
8742     DeclRefExpr *RL = dyn_cast<DeclRefExpr>(OL->getBase()->IgnoreImpCasts());
8743     DeclRefExpr *RR = dyn_cast<DeclRefExpr>(OR->getBase()->IgnoreImpCasts());
8744     if (RL && RR && RL->getDecl() == RR->getDecl())
8745       Sema.Diag(Loc, diag::warn_identity_field_assign) << 1;
8746   }
8747 }
8748 
8749 // C99 6.5.16.1
CheckAssignmentOperands(Expr * LHSExpr,ExprResult & RHS,SourceLocation Loc,QualType CompoundType)8750 QualType Sema::CheckAssignmentOperands(Expr *LHSExpr, ExprResult &RHS,
8751                                        SourceLocation Loc,
8752                                        QualType CompoundType) {
8753   assert(!LHSExpr->hasPlaceholderType(BuiltinType::PseudoObject));
8754 
8755   // Verify that LHS is a modifiable lvalue, and emit error if not.
8756   if (CheckForModifiableLvalue(LHSExpr, Loc, *this))
8757     return QualType();
8758 
8759   QualType LHSType = LHSExpr->getType();
8760   QualType RHSType = CompoundType.isNull() ? RHS.get()->getType() :
8761                                              CompoundType;
8762   AssignConvertType ConvTy;
8763   if (CompoundType.isNull()) {
8764     Expr *RHSCheck = RHS.get();
8765 
8766     CheckIdentityFieldAssignment(LHSExpr, RHSCheck, Loc, *this);
8767 
8768     QualType LHSTy(LHSType);
8769     ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS);
8770     if (RHS.isInvalid())
8771       return QualType();
8772     // Special case of NSObject attributes on c-style pointer types.
8773     if (ConvTy == IncompatiblePointer &&
8774         ((Context.isObjCNSObjectType(LHSType) &&
8775           RHSType->isObjCObjectPointerType()) ||
8776          (Context.isObjCNSObjectType(RHSType) &&
8777           LHSType->isObjCObjectPointerType())))
8778       ConvTy = Compatible;
8779 
8780     if (ConvTy == Compatible &&
8781         LHSType->isObjCObjectType())
8782         Diag(Loc, diag::err_objc_object_assignment)
8783           << LHSType;
8784 
8785     // If the RHS is a unary plus or minus, check to see if they = and + are
8786     // right next to each other.  If so, the user may have typo'd "x =+ 4"
8787     // instead of "x += 4".
8788     if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(RHSCheck))
8789       RHSCheck = ICE->getSubExpr();
8790     if (UnaryOperator *UO = dyn_cast<UnaryOperator>(RHSCheck)) {
8791       if ((UO->getOpcode() == UO_Plus ||
8792            UO->getOpcode() == UO_Minus) &&
8793           Loc.isFileID() && UO->getOperatorLoc().isFileID() &&
8794           // Only if the two operators are exactly adjacent.
8795           Loc.getLocWithOffset(1) == UO->getOperatorLoc() &&
8796           // And there is a space or other character before the subexpr of the
8797           // unary +/-.  We don't want to warn on "x=-1".
8798           Loc.getLocWithOffset(2) != UO->getSubExpr()->getLocStart() &&
8799           UO->getSubExpr()->getLocStart().isFileID()) {
8800         Diag(Loc, diag::warn_not_compound_assign)
8801           << (UO->getOpcode() == UO_Plus ? "+" : "-")
8802           << SourceRange(UO->getOperatorLoc(), UO->getOperatorLoc());
8803       }
8804     }
8805 
8806     if (ConvTy == Compatible) {
8807       if (LHSType.getObjCLifetime() == Qualifiers::OCL_Strong) {
8808         // Warn about retain cycles where a block captures the LHS, but
8809         // not if the LHS is a simple variable into which the block is
8810         // being stored...unless that variable can be captured by reference!
8811         const Expr *InnerLHS = LHSExpr->IgnoreParenCasts();
8812         const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(InnerLHS);
8813         if (!DRE || DRE->getDecl()->hasAttr<BlocksAttr>())
8814           checkRetainCycles(LHSExpr, RHS.get());
8815 
8816         // It is safe to assign a weak reference into a strong variable.
8817         // Although this code can still have problems:
8818         //   id x = self.weakProp;
8819         //   id y = self.weakProp;
8820         // we do not warn to warn spuriously when 'x' and 'y' are on separate
8821         // paths through the function. This should be revisited if
8822         // -Wrepeated-use-of-weak is made flow-sensitive.
8823         if (!Diags.isIgnored(diag::warn_arc_repeated_use_of_weak,
8824                              RHS.get()->getLocStart()))
8825           getCurFunction()->markSafeWeakUse(RHS.get());
8826 
8827       } else if (getLangOpts().ObjCAutoRefCount) {
8828         checkUnsafeExprAssigns(Loc, LHSExpr, RHS.get());
8829       }
8830     }
8831   } else {
8832     // Compound assignment "x += y"
8833     ConvTy = CheckAssignmentConstraints(Loc, LHSType, RHSType);
8834   }
8835 
8836   if (DiagnoseAssignmentResult(ConvTy, Loc, LHSType, RHSType,
8837                                RHS.get(), AA_Assigning))
8838     return QualType();
8839 
8840   CheckForNullPointerDereference(*this, LHSExpr);
8841 
8842   // C99 6.5.16p3: The type of an assignment expression is the type of the
8843   // left operand unless the left operand has qualified type, in which case
8844   // it is the unqualified version of the type of the left operand.
8845   // C99 6.5.16.1p2: In simple assignment, the value of the right operand
8846   // is converted to the type of the assignment expression (above).
8847   // C++ 5.17p1: the type of the assignment expression is that of its left
8848   // operand.
8849   return (getLangOpts().CPlusPlus
8850           ? LHSType : LHSType.getUnqualifiedType());
8851 }
8852 
8853 // C99 6.5.17
CheckCommaOperands(Sema & S,ExprResult & LHS,ExprResult & RHS,SourceLocation Loc)8854 static QualType CheckCommaOperands(Sema &S, ExprResult &LHS, ExprResult &RHS,
8855                                    SourceLocation Loc) {
8856   LHS = S.CheckPlaceholderExpr(LHS.get());
8857   RHS = S.CheckPlaceholderExpr(RHS.get());
8858   if (LHS.isInvalid() || RHS.isInvalid())
8859     return QualType();
8860 
8861   // C's comma performs lvalue conversion (C99 6.3.2.1) on both its
8862   // operands, but not unary promotions.
8863   // C++'s comma does not do any conversions at all (C++ [expr.comma]p1).
8864 
8865   // So we treat the LHS as a ignored value, and in C++ we allow the
8866   // containing site to determine what should be done with the RHS.
8867   LHS = S.IgnoredValueConversions(LHS.get());
8868   if (LHS.isInvalid())
8869     return QualType();
8870 
8871   S.DiagnoseUnusedExprResult(LHS.get());
8872 
8873   if (!S.getLangOpts().CPlusPlus) {
8874     RHS = S.DefaultFunctionArrayLvalueConversion(RHS.get());
8875     if (RHS.isInvalid())
8876       return QualType();
8877     if (!RHS.get()->getType()->isVoidType())
8878       S.RequireCompleteType(Loc, RHS.get()->getType(),
8879                             diag::err_incomplete_type);
8880   }
8881 
8882   return RHS.get()->getType();
8883 }
8884 
8885 /// CheckIncrementDecrementOperand - unlike most "Check" methods, this routine
8886 /// doesn't need to call UsualUnaryConversions or UsualArithmeticConversions.
CheckIncrementDecrementOperand(Sema & S,Expr * Op,ExprValueKind & VK,ExprObjectKind & OK,SourceLocation OpLoc,bool IsInc,bool IsPrefix)8887 static QualType CheckIncrementDecrementOperand(Sema &S, Expr *Op,
8888                                                ExprValueKind &VK,
8889                                                ExprObjectKind &OK,
8890                                                SourceLocation OpLoc,
8891                                                bool IsInc, bool IsPrefix) {
8892   if (Op->isTypeDependent())
8893     return S.Context.DependentTy;
8894 
8895   QualType ResType = Op->getType();
8896   // Atomic types can be used for increment / decrement where the non-atomic
8897   // versions can, so ignore the _Atomic() specifier for the purpose of
8898   // checking.
8899   if (const AtomicType *ResAtomicType = ResType->getAs<AtomicType>())
8900     ResType = ResAtomicType->getValueType();
8901 
8902   assert(!ResType.isNull() && "no type for increment/decrement expression");
8903 
8904   if (S.getLangOpts().CPlusPlus && ResType->isBooleanType()) {
8905     // Decrement of bool is not allowed.
8906     if (!IsInc) {
8907       S.Diag(OpLoc, diag::err_decrement_bool) << Op->getSourceRange();
8908       return QualType();
8909     }
8910     // Increment of bool sets it to true, but is deprecated.
8911     S.Diag(OpLoc, diag::warn_increment_bool) << Op->getSourceRange();
8912   } else if (S.getLangOpts().CPlusPlus && ResType->isEnumeralType()) {
8913     // Error on enum increments and decrements in C++ mode
8914     S.Diag(OpLoc, diag::err_increment_decrement_enum) << IsInc << ResType;
8915     return QualType();
8916   } else if (ResType->isRealType()) {
8917     // OK!
8918   } else if (ResType->isPointerType()) {
8919     // C99 6.5.2.4p2, 6.5.6p2
8920     if (!checkArithmeticOpPointerOperand(S, OpLoc, Op))
8921       return QualType();
8922   } else if (ResType->isObjCObjectPointerType()) {
8923     // On modern runtimes, ObjC pointer arithmetic is forbidden.
8924     // Otherwise, we just need a complete type.
8925     if (checkArithmeticIncompletePointerType(S, OpLoc, Op) ||
8926         checkArithmeticOnObjCPointer(S, OpLoc, Op))
8927       return QualType();
8928   } else if (ResType->isAnyComplexType()) {
8929     // C99 does not support ++/-- on complex types, we allow as an extension.
8930     S.Diag(OpLoc, diag::ext_integer_increment_complex)
8931       << ResType << Op->getSourceRange();
8932   } else if (ResType->isPlaceholderType()) {
8933     ExprResult PR = S.CheckPlaceholderExpr(Op);
8934     if (PR.isInvalid()) return QualType();
8935     return CheckIncrementDecrementOperand(S, PR.get(), VK, OK, OpLoc,
8936                                           IsInc, IsPrefix);
8937   } else if (S.getLangOpts().AltiVec && ResType->isVectorType()) {
8938     // OK! ( C/C++ Language Extensions for CBEA(Version 2.6) 10.3 )
8939   } else if(S.getLangOpts().OpenCL && ResType->isVectorType() &&
8940             ResType->getAs<VectorType>()->getElementType()->isIntegerType()) {
8941     // OpenCL V1.2 6.3 says dec/inc ops operate on integer vector types.
8942   } else {
8943     S.Diag(OpLoc, diag::err_typecheck_illegal_increment_decrement)
8944       << ResType << int(IsInc) << Op->getSourceRange();
8945     return QualType();
8946   }
8947   // At this point, we know we have a real, complex or pointer type.
8948   // Now make sure the operand is a modifiable lvalue.
8949   if (CheckForModifiableLvalue(Op, OpLoc, S))
8950     return QualType();
8951   // In C++, a prefix increment is the same type as the operand. Otherwise
8952   // (in C or with postfix), the increment is the unqualified type of the
8953   // operand.
8954   if (IsPrefix && S.getLangOpts().CPlusPlus) {
8955     VK = VK_LValue;
8956     OK = Op->getObjectKind();
8957     return ResType;
8958   } else {
8959     VK = VK_RValue;
8960     return ResType.getUnqualifiedType();
8961   }
8962 }
8963 
8964 
8965 /// getPrimaryDecl - Helper function for CheckAddressOfOperand().
8966 /// This routine allows us to typecheck complex/recursive expressions
8967 /// where the declaration is needed for type checking. We only need to
8968 /// handle cases when the expression references a function designator
8969 /// or is an lvalue. Here are some examples:
8970 ///  - &(x) => x
8971 ///  - &*****f => f for f a function designator.
8972 ///  - &s.xx => s
8973 ///  - &s.zz[1].yy -> s, if zz is an array
8974 ///  - *(x + 1) -> x, if x is an array
8975 ///  - &"123"[2] -> 0
8976 ///  - & __real__ x -> x
getPrimaryDecl(Expr * E)8977 static ValueDecl *getPrimaryDecl(Expr *E) {
8978   switch (E->getStmtClass()) {
8979   case Stmt::DeclRefExprClass:
8980     return cast<DeclRefExpr>(E)->getDecl();
8981   case Stmt::MemberExprClass:
8982     // If this is an arrow operator, the address is an offset from
8983     // the base's value, so the object the base refers to is
8984     // irrelevant.
8985     if (cast<MemberExpr>(E)->isArrow())
8986       return nullptr;
8987     // Otherwise, the expression refers to a part of the base
8988     return getPrimaryDecl(cast<MemberExpr>(E)->getBase());
8989   case Stmt::ArraySubscriptExprClass: {
8990     // FIXME: This code shouldn't be necessary!  We should catch the implicit
8991     // promotion of register arrays earlier.
8992     Expr* Base = cast<ArraySubscriptExpr>(E)->getBase();
8993     if (ImplicitCastExpr* ICE = dyn_cast<ImplicitCastExpr>(Base)) {
8994       if (ICE->getSubExpr()->getType()->isArrayType())
8995         return getPrimaryDecl(ICE->getSubExpr());
8996     }
8997     return nullptr;
8998   }
8999   case Stmt::UnaryOperatorClass: {
9000     UnaryOperator *UO = cast<UnaryOperator>(E);
9001 
9002     switch(UO->getOpcode()) {
9003     case UO_Real:
9004     case UO_Imag:
9005     case UO_Extension:
9006       return getPrimaryDecl(UO->getSubExpr());
9007     default:
9008       return nullptr;
9009     }
9010   }
9011   case Stmt::ParenExprClass:
9012     return getPrimaryDecl(cast<ParenExpr>(E)->getSubExpr());
9013   case Stmt::ImplicitCastExprClass:
9014     // If the result of an implicit cast is an l-value, we care about
9015     // the sub-expression; otherwise, the result here doesn't matter.
9016     return getPrimaryDecl(cast<ImplicitCastExpr>(E)->getSubExpr());
9017   default:
9018     return nullptr;
9019   }
9020 }
9021 
9022 namespace {
9023   enum {
9024     AO_Bit_Field = 0,
9025     AO_Vector_Element = 1,
9026     AO_Property_Expansion = 2,
9027     AO_Register_Variable = 3,
9028     AO_No_Error = 4
9029   };
9030 }
9031 /// \brief Diagnose invalid operand for address of operations.
9032 ///
9033 /// \param Type The type of operand which cannot have its address taken.
diagnoseAddressOfInvalidType(Sema & S,SourceLocation Loc,Expr * E,unsigned Type)9034 static void diagnoseAddressOfInvalidType(Sema &S, SourceLocation Loc,
9035                                          Expr *E, unsigned Type) {
9036   S.Diag(Loc, diag::err_typecheck_address_of) << Type << E->getSourceRange();
9037 }
9038 
9039 /// CheckAddressOfOperand - The operand of & must be either a function
9040 /// designator or an lvalue designating an object. If it is an lvalue, the
9041 /// object cannot be declared with storage class register or be a bit field.
9042 /// Note: The usual conversions are *not* applied to the operand of the &
9043 /// operator (C99 6.3.2.1p[2-4]), and its result is never an lvalue.
9044 /// In C++, the operand might be an overloaded function name, in which case
9045 /// we allow the '&' but retain the overloaded-function type.
CheckAddressOfOperand(ExprResult & OrigOp,SourceLocation OpLoc)9046 QualType Sema::CheckAddressOfOperand(ExprResult &OrigOp, SourceLocation OpLoc) {
9047   if (const BuiltinType *PTy = OrigOp.get()->getType()->getAsPlaceholderType()){
9048     if (PTy->getKind() == BuiltinType::Overload) {
9049       Expr *E = OrigOp.get()->IgnoreParens();
9050       if (!isa<OverloadExpr>(E)) {
9051         assert(cast<UnaryOperator>(E)->getOpcode() == UO_AddrOf);
9052         Diag(OpLoc, diag::err_typecheck_invalid_lvalue_addrof_addrof_function)
9053           << OrigOp.get()->getSourceRange();
9054         return QualType();
9055       }
9056 
9057       OverloadExpr *Ovl = cast<OverloadExpr>(E);
9058       if (isa<UnresolvedMemberExpr>(Ovl))
9059         if (!ResolveSingleFunctionTemplateSpecialization(Ovl)) {
9060           Diag(OpLoc, diag::err_invalid_form_pointer_member_function)
9061             << OrigOp.get()->getSourceRange();
9062           return QualType();
9063         }
9064 
9065       return Context.OverloadTy;
9066     }
9067 
9068     if (PTy->getKind() == BuiltinType::UnknownAny)
9069       return Context.UnknownAnyTy;
9070 
9071     if (PTy->getKind() == BuiltinType::BoundMember) {
9072       Diag(OpLoc, diag::err_invalid_form_pointer_member_function)
9073         << OrigOp.get()->getSourceRange();
9074       return QualType();
9075     }
9076 
9077     OrigOp = CheckPlaceholderExpr(OrigOp.get());
9078     if (OrigOp.isInvalid()) return QualType();
9079   }
9080 
9081   if (OrigOp.get()->isTypeDependent())
9082     return Context.DependentTy;
9083 
9084   assert(!OrigOp.get()->getType()->isPlaceholderType());
9085 
9086   // Make sure to ignore parentheses in subsequent checks
9087   Expr *op = OrigOp.get()->IgnoreParens();
9088 
9089   // OpenCL v1.0 s6.8.a.3: Pointers to functions are not allowed.
9090   if (LangOpts.OpenCL && op->getType()->isFunctionType()) {
9091     Diag(op->getExprLoc(), diag::err_opencl_taking_function_address);
9092     return QualType();
9093   }
9094 
9095   if (getLangOpts().C99) {
9096     // Implement C99-only parts of addressof rules.
9097     if (UnaryOperator* uOp = dyn_cast<UnaryOperator>(op)) {
9098       if (uOp->getOpcode() == UO_Deref)
9099         // Per C99 6.5.3.2, the address of a deref always returns a valid result
9100         // (assuming the deref expression is valid).
9101         return uOp->getSubExpr()->getType();
9102     }
9103     // Technically, there should be a check for array subscript
9104     // expressions here, but the result of one is always an lvalue anyway.
9105   }
9106   ValueDecl *dcl = getPrimaryDecl(op);
9107   Expr::LValueClassification lval = op->ClassifyLValue(Context);
9108   unsigned AddressOfError = AO_No_Error;
9109 
9110   if (lval == Expr::LV_ClassTemporary || lval == Expr::LV_ArrayTemporary) {
9111     bool sfinae = (bool)isSFINAEContext();
9112     Diag(OpLoc, isSFINAEContext() ? diag::err_typecheck_addrof_temporary
9113                                   : diag::ext_typecheck_addrof_temporary)
9114       << op->getType() << op->getSourceRange();
9115     if (sfinae)
9116       return QualType();
9117     // Materialize the temporary as an lvalue so that we can take its address.
9118     OrigOp = op = new (Context)
9119         MaterializeTemporaryExpr(op->getType(), OrigOp.get(), true);
9120   } else if (isa<ObjCSelectorExpr>(op)) {
9121     return Context.getPointerType(op->getType());
9122   } else if (lval == Expr::LV_MemberFunction) {
9123     // If it's an instance method, make a member pointer.
9124     // The expression must have exactly the form &A::foo.
9125 
9126     // If the underlying expression isn't a decl ref, give up.
9127     if (!isa<DeclRefExpr>(op)) {
9128       Diag(OpLoc, diag::err_invalid_form_pointer_member_function)
9129         << OrigOp.get()->getSourceRange();
9130       return QualType();
9131     }
9132     DeclRefExpr *DRE = cast<DeclRefExpr>(op);
9133     CXXMethodDecl *MD = cast<CXXMethodDecl>(DRE->getDecl());
9134 
9135     // The id-expression was parenthesized.
9136     if (OrigOp.get() != DRE) {
9137       Diag(OpLoc, diag::err_parens_pointer_member_function)
9138         << OrigOp.get()->getSourceRange();
9139 
9140     // The method was named without a qualifier.
9141     } else if (!DRE->getQualifier()) {
9142       if (MD->getParent()->getName().empty())
9143         Diag(OpLoc, diag::err_unqualified_pointer_member_function)
9144           << op->getSourceRange();
9145       else {
9146         SmallString<32> Str;
9147         StringRef Qual = (MD->getParent()->getName() + "::").toStringRef(Str);
9148         Diag(OpLoc, diag::err_unqualified_pointer_member_function)
9149           << op->getSourceRange()
9150           << FixItHint::CreateInsertion(op->getSourceRange().getBegin(), Qual);
9151       }
9152     }
9153 
9154     // Taking the address of a dtor is illegal per C++ [class.dtor]p2.
9155     if (isa<CXXDestructorDecl>(MD))
9156       Diag(OpLoc, diag::err_typecheck_addrof_dtor) << op->getSourceRange();
9157 
9158     QualType MPTy = Context.getMemberPointerType(
9159         op->getType(), Context.getTypeDeclType(MD->getParent()).getTypePtr());
9160     if (Context.getTargetInfo().getCXXABI().isMicrosoft())
9161       RequireCompleteType(OpLoc, MPTy, 0);
9162     return MPTy;
9163   } else if (lval != Expr::LV_Valid && lval != Expr::LV_IncompleteVoidType) {
9164     // C99 6.5.3.2p1
9165     // The operand must be either an l-value or a function designator
9166     if (!op->getType()->isFunctionType()) {
9167       // Use a special diagnostic for loads from property references.
9168       if (isa<PseudoObjectExpr>(op)) {
9169         AddressOfError = AO_Property_Expansion;
9170       } else {
9171         Diag(OpLoc, diag::err_typecheck_invalid_lvalue_addrof)
9172           << op->getType() << op->getSourceRange();
9173         return QualType();
9174       }
9175     }
9176   } else if (op->getObjectKind() == OK_BitField) { // C99 6.5.3.2p1
9177     // The operand cannot be a bit-field
9178     AddressOfError = AO_Bit_Field;
9179   } else if (op->getObjectKind() == OK_VectorComponent) {
9180     // The operand cannot be an element of a vector
9181     AddressOfError = AO_Vector_Element;
9182   } else if (dcl) { // C99 6.5.3.2p1
9183     // We have an lvalue with a decl. Make sure the decl is not declared
9184     // with the register storage-class specifier.
9185     if (const VarDecl *vd = dyn_cast<VarDecl>(dcl)) {
9186       // in C++ it is not error to take address of a register
9187       // variable (c++03 7.1.1P3)
9188       if (vd->getStorageClass() == SC_Register &&
9189           !getLangOpts().CPlusPlus) {
9190         AddressOfError = AO_Register_Variable;
9191       }
9192     } else if (isa<FunctionTemplateDecl>(dcl)) {
9193       return Context.OverloadTy;
9194     } else if (isa<FieldDecl>(dcl) || isa<IndirectFieldDecl>(dcl)) {
9195       // Okay: we can take the address of a field.
9196       // Could be a pointer to member, though, if there is an explicit
9197       // scope qualifier for the class.
9198       if (isa<DeclRefExpr>(op) && cast<DeclRefExpr>(op)->getQualifier()) {
9199         DeclContext *Ctx = dcl->getDeclContext();
9200         if (Ctx && Ctx->isRecord()) {
9201           if (dcl->getType()->isReferenceType()) {
9202             Diag(OpLoc,
9203                  diag::err_cannot_form_pointer_to_member_of_reference_type)
9204               << dcl->getDeclName() << dcl->getType();
9205             return QualType();
9206           }
9207 
9208           while (cast<RecordDecl>(Ctx)->isAnonymousStructOrUnion())
9209             Ctx = Ctx->getParent();
9210 
9211           QualType MPTy = Context.getMemberPointerType(
9212               op->getType(),
9213               Context.getTypeDeclType(cast<RecordDecl>(Ctx)).getTypePtr());
9214           if (Context.getTargetInfo().getCXXABI().isMicrosoft())
9215             RequireCompleteType(OpLoc, MPTy, 0);
9216           return MPTy;
9217         }
9218       }
9219     } else if (!isa<FunctionDecl>(dcl) && !isa<NonTypeTemplateParmDecl>(dcl))
9220       llvm_unreachable("Unknown/unexpected decl type");
9221   }
9222 
9223   if (AddressOfError != AO_No_Error) {
9224     diagnoseAddressOfInvalidType(*this, OpLoc, op, AddressOfError);
9225     return QualType();
9226   }
9227 
9228   if (lval == Expr::LV_IncompleteVoidType) {
9229     // Taking the address of a void variable is technically illegal, but we
9230     // allow it in cases which are otherwise valid.
9231     // Example: "extern void x; void* y = &x;".
9232     Diag(OpLoc, diag::ext_typecheck_addrof_void) << op->getSourceRange();
9233   }
9234 
9235   // If the operand has type "type", the result has type "pointer to type".
9236   if (op->getType()->isObjCObjectType())
9237     return Context.getObjCObjectPointerType(op->getType());
9238   return Context.getPointerType(op->getType());
9239 }
9240 
RecordModifiableNonNullParam(Sema & S,const Expr * Exp)9241 static void RecordModifiableNonNullParam(Sema &S, const Expr *Exp) {
9242   const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Exp);
9243   if (!DRE)
9244     return;
9245   const Decl *D = DRE->getDecl();
9246   if (!D)
9247     return;
9248   const ParmVarDecl *Param = dyn_cast<ParmVarDecl>(D);
9249   if (!Param)
9250     return;
9251   if (const FunctionDecl* FD = dyn_cast<FunctionDecl>(Param->getDeclContext()))
9252     if (!FD->hasAttr<NonNullAttr>() && !Param->hasAttr<NonNullAttr>())
9253       return;
9254   if (FunctionScopeInfo *FD = S.getCurFunction())
9255     if (!FD->ModifiedNonNullParams.count(Param))
9256       FD->ModifiedNonNullParams.insert(Param);
9257 }
9258 
9259 /// CheckIndirectionOperand - Type check unary indirection (prefix '*').
CheckIndirectionOperand(Sema & S,Expr * Op,ExprValueKind & VK,SourceLocation OpLoc)9260 static QualType CheckIndirectionOperand(Sema &S, Expr *Op, ExprValueKind &VK,
9261                                         SourceLocation OpLoc) {
9262   if (Op->isTypeDependent())
9263     return S.Context.DependentTy;
9264 
9265   ExprResult ConvResult = S.UsualUnaryConversions(Op);
9266   if (ConvResult.isInvalid())
9267     return QualType();
9268   Op = ConvResult.get();
9269   QualType OpTy = Op->getType();
9270   QualType Result;
9271 
9272   if (isa<CXXReinterpretCastExpr>(Op)) {
9273     QualType OpOrigType = Op->IgnoreParenCasts()->getType();
9274     S.CheckCompatibleReinterpretCast(OpOrigType, OpTy, /*IsDereference*/true,
9275                                      Op->getSourceRange());
9276   }
9277 
9278   if (const PointerType *PT = OpTy->getAs<PointerType>())
9279     Result = PT->getPointeeType();
9280   else if (const ObjCObjectPointerType *OPT =
9281              OpTy->getAs<ObjCObjectPointerType>())
9282     Result = OPT->getPointeeType();
9283   else {
9284     ExprResult PR = S.CheckPlaceholderExpr(Op);
9285     if (PR.isInvalid()) return QualType();
9286     if (PR.get() != Op)
9287       return CheckIndirectionOperand(S, PR.get(), VK, OpLoc);
9288   }
9289 
9290   if (Result.isNull()) {
9291     S.Diag(OpLoc, diag::err_typecheck_indirection_requires_pointer)
9292       << OpTy << Op->getSourceRange();
9293     return QualType();
9294   }
9295 
9296   // Note that per both C89 and C99, indirection is always legal, even if Result
9297   // is an incomplete type or void.  It would be possible to warn about
9298   // dereferencing a void pointer, but it's completely well-defined, and such a
9299   // warning is unlikely to catch any mistakes. In C++, indirection is not valid
9300   // for pointers to 'void' but is fine for any other pointer type:
9301   //
9302   // C++ [expr.unary.op]p1:
9303   //   [...] the expression to which [the unary * operator] is applied shall
9304   //   be a pointer to an object type, or a pointer to a function type
9305   if (S.getLangOpts().CPlusPlus && Result->isVoidType())
9306     S.Diag(OpLoc, diag::ext_typecheck_indirection_through_void_pointer)
9307       << OpTy << Op->getSourceRange();
9308 
9309   // Dereferences are usually l-values...
9310   VK = VK_LValue;
9311 
9312   // ...except that certain expressions are never l-values in C.
9313   if (!S.getLangOpts().CPlusPlus && Result.isCForbiddenLValueType())
9314     VK = VK_RValue;
9315 
9316   return Result;
9317 }
9318 
ConvertTokenKindToBinaryOpcode(tok::TokenKind Kind)9319 BinaryOperatorKind Sema::ConvertTokenKindToBinaryOpcode(tok::TokenKind Kind) {
9320   BinaryOperatorKind Opc;
9321   switch (Kind) {
9322   default: llvm_unreachable("Unknown binop!");
9323   case tok::periodstar:           Opc = BO_PtrMemD; break;
9324   case tok::arrowstar:            Opc = BO_PtrMemI; break;
9325   case tok::star:                 Opc = BO_Mul; break;
9326   case tok::slash:                Opc = BO_Div; break;
9327   case tok::percent:              Opc = BO_Rem; break;
9328   case tok::plus:                 Opc = BO_Add; break;
9329   case tok::minus:                Opc = BO_Sub; break;
9330   case tok::lessless:             Opc = BO_Shl; break;
9331   case tok::greatergreater:       Opc = BO_Shr; break;
9332   case tok::lessequal:            Opc = BO_LE; break;
9333   case tok::less:                 Opc = BO_LT; break;
9334   case tok::greaterequal:         Opc = BO_GE; break;
9335   case tok::greater:              Opc = BO_GT; break;
9336   case tok::exclaimequal:         Opc = BO_NE; break;
9337   case tok::equalequal:           Opc = BO_EQ; break;
9338   case tok::amp:                  Opc = BO_And; break;
9339   case tok::caret:                Opc = BO_Xor; break;
9340   case tok::pipe:                 Opc = BO_Or; break;
9341   case tok::ampamp:               Opc = BO_LAnd; break;
9342   case tok::pipepipe:             Opc = BO_LOr; break;
9343   case tok::equal:                Opc = BO_Assign; break;
9344   case tok::starequal:            Opc = BO_MulAssign; break;
9345   case tok::slashequal:           Opc = BO_DivAssign; break;
9346   case tok::percentequal:         Opc = BO_RemAssign; break;
9347   case tok::plusequal:            Opc = BO_AddAssign; break;
9348   case tok::minusequal:           Opc = BO_SubAssign; break;
9349   case tok::lesslessequal:        Opc = BO_ShlAssign; break;
9350   case tok::greatergreaterequal:  Opc = BO_ShrAssign; break;
9351   case tok::ampequal:             Opc = BO_AndAssign; break;
9352   case tok::caretequal:           Opc = BO_XorAssign; break;
9353   case tok::pipeequal:            Opc = BO_OrAssign; break;
9354   case tok::comma:                Opc = BO_Comma; break;
9355   }
9356   return Opc;
9357 }
9358 
ConvertTokenKindToUnaryOpcode(tok::TokenKind Kind)9359 static inline UnaryOperatorKind ConvertTokenKindToUnaryOpcode(
9360   tok::TokenKind Kind) {
9361   UnaryOperatorKind Opc;
9362   switch (Kind) {
9363   default: llvm_unreachable("Unknown unary op!");
9364   case tok::plusplus:     Opc = UO_PreInc; break;
9365   case tok::minusminus:   Opc = UO_PreDec; break;
9366   case tok::amp:          Opc = UO_AddrOf; break;
9367   case tok::star:         Opc = UO_Deref; break;
9368   case tok::plus:         Opc = UO_Plus; break;
9369   case tok::minus:        Opc = UO_Minus; break;
9370   case tok::tilde:        Opc = UO_Not; break;
9371   case tok::exclaim:      Opc = UO_LNot; break;
9372   case tok::kw___real:    Opc = UO_Real; break;
9373   case tok::kw___imag:    Opc = UO_Imag; break;
9374   case tok::kw___extension__: Opc = UO_Extension; break;
9375   }
9376   return Opc;
9377 }
9378 
9379 /// DiagnoseSelfAssignment - Emits a warning if a value is assigned to itself.
9380 /// This warning is only emitted for builtin assignment operations. It is also
9381 /// suppressed in the event of macro expansions.
DiagnoseSelfAssignment(Sema & S,Expr * LHSExpr,Expr * RHSExpr,SourceLocation OpLoc)9382 static void DiagnoseSelfAssignment(Sema &S, Expr *LHSExpr, Expr *RHSExpr,
9383                                    SourceLocation OpLoc) {
9384   if (!S.ActiveTemplateInstantiations.empty())
9385     return;
9386   if (OpLoc.isInvalid() || OpLoc.isMacroID())
9387     return;
9388   LHSExpr = LHSExpr->IgnoreParenImpCasts();
9389   RHSExpr = RHSExpr->IgnoreParenImpCasts();
9390   const DeclRefExpr *LHSDeclRef = dyn_cast<DeclRefExpr>(LHSExpr);
9391   const DeclRefExpr *RHSDeclRef = dyn_cast<DeclRefExpr>(RHSExpr);
9392   if (!LHSDeclRef || !RHSDeclRef ||
9393       LHSDeclRef->getLocation().isMacroID() ||
9394       RHSDeclRef->getLocation().isMacroID())
9395     return;
9396   const ValueDecl *LHSDecl =
9397     cast<ValueDecl>(LHSDeclRef->getDecl()->getCanonicalDecl());
9398   const ValueDecl *RHSDecl =
9399     cast<ValueDecl>(RHSDeclRef->getDecl()->getCanonicalDecl());
9400   if (LHSDecl != RHSDecl)
9401     return;
9402   if (LHSDecl->getType().isVolatileQualified())
9403     return;
9404   if (const ReferenceType *RefTy = LHSDecl->getType()->getAs<ReferenceType>())
9405     if (RefTy->getPointeeType().isVolatileQualified())
9406       return;
9407 
9408   S.Diag(OpLoc, diag::warn_self_assignment)
9409       << LHSDeclRef->getType()
9410       << LHSExpr->getSourceRange() << RHSExpr->getSourceRange();
9411 }
9412 
9413 /// Check if a bitwise-& is performed on an Objective-C pointer.  This
9414 /// is usually indicative of introspection within the Objective-C pointer.
checkObjCPointerIntrospection(Sema & S,ExprResult & L,ExprResult & R,SourceLocation OpLoc)9415 static void checkObjCPointerIntrospection(Sema &S, ExprResult &L, ExprResult &R,
9416                                           SourceLocation OpLoc) {
9417   if (!S.getLangOpts().ObjC1)
9418     return;
9419 
9420   const Expr *ObjCPointerExpr = nullptr, *OtherExpr = nullptr;
9421   const Expr *LHS = L.get();
9422   const Expr *RHS = R.get();
9423 
9424   if (LHS->IgnoreParenCasts()->getType()->isObjCObjectPointerType()) {
9425     ObjCPointerExpr = LHS;
9426     OtherExpr = RHS;
9427   }
9428   else if (RHS->IgnoreParenCasts()->getType()->isObjCObjectPointerType()) {
9429     ObjCPointerExpr = RHS;
9430     OtherExpr = LHS;
9431   }
9432 
9433   // This warning is deliberately made very specific to reduce false
9434   // positives with logic that uses '&' for hashing.  This logic mainly
9435   // looks for code trying to introspect into tagged pointers, which
9436   // code should generally never do.
9437   if (ObjCPointerExpr && isa<IntegerLiteral>(OtherExpr->IgnoreParenCasts())) {
9438     unsigned Diag = diag::warn_objc_pointer_masking;
9439     // Determine if we are introspecting the result of performSelectorXXX.
9440     const Expr *Ex = ObjCPointerExpr->IgnoreParenCasts();
9441     // Special case messages to -performSelector and friends, which
9442     // can return non-pointer values boxed in a pointer value.
9443     // Some clients may wish to silence warnings in this subcase.
9444     if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(Ex)) {
9445       Selector S = ME->getSelector();
9446       StringRef SelArg0 = S.getNameForSlot(0);
9447       if (SelArg0.startswith("performSelector"))
9448         Diag = diag::warn_objc_pointer_masking_performSelector;
9449     }
9450 
9451     S.Diag(OpLoc, Diag)
9452       << ObjCPointerExpr->getSourceRange();
9453   }
9454 }
9455 
getDeclFromExpr(Expr * E)9456 static NamedDecl *getDeclFromExpr(Expr *E) {
9457   if (!E)
9458     return nullptr;
9459   if (auto *DRE = dyn_cast<DeclRefExpr>(E))
9460     return DRE->getDecl();
9461   if (auto *ME = dyn_cast<MemberExpr>(E))
9462     return ME->getMemberDecl();
9463   if (auto *IRE = dyn_cast<ObjCIvarRefExpr>(E))
9464     return IRE->getDecl();
9465   return nullptr;
9466 }
9467 
9468 /// CreateBuiltinBinOp - Creates a new built-in binary operation with
9469 /// operator @p Opc at location @c TokLoc. This routine only supports
9470 /// built-in operations; ActOnBinOp handles overloaded operators.
CreateBuiltinBinOp(SourceLocation OpLoc,BinaryOperatorKind Opc,Expr * LHSExpr,Expr * RHSExpr)9471 ExprResult Sema::CreateBuiltinBinOp(SourceLocation OpLoc,
9472                                     BinaryOperatorKind Opc,
9473                                     Expr *LHSExpr, Expr *RHSExpr) {
9474   if (getLangOpts().CPlusPlus11 && isa<InitListExpr>(RHSExpr)) {
9475     // The syntax only allows initializer lists on the RHS of assignment,
9476     // so we don't need to worry about accepting invalid code for
9477     // non-assignment operators.
9478     // C++11 5.17p9:
9479     //   The meaning of x = {v} [...] is that of x = T(v) [...]. The meaning
9480     //   of x = {} is x = T().
9481     InitializationKind Kind =
9482         InitializationKind::CreateDirectList(RHSExpr->getLocStart());
9483     InitializedEntity Entity =
9484         InitializedEntity::InitializeTemporary(LHSExpr->getType());
9485     InitializationSequence InitSeq(*this, Entity, Kind, RHSExpr);
9486     ExprResult Init = InitSeq.Perform(*this, Entity, Kind, RHSExpr);
9487     if (Init.isInvalid())
9488       return Init;
9489     RHSExpr = Init.get();
9490   }
9491 
9492   ExprResult LHS = LHSExpr, RHS = RHSExpr;
9493   QualType ResultTy;     // Result type of the binary operator.
9494   // The following two variables are used for compound assignment operators
9495   QualType CompLHSTy;    // Type of LHS after promotions for computation
9496   QualType CompResultTy; // Type of computation result
9497   ExprValueKind VK = VK_RValue;
9498   ExprObjectKind OK = OK_Ordinary;
9499 
9500   if (!getLangOpts().CPlusPlus) {
9501     // C cannot handle TypoExpr nodes on either side of a binop because it
9502     // doesn't handle dependent types properly, so make sure any TypoExprs have
9503     // been dealt with before checking the operands.
9504     LHS = CorrectDelayedTyposInExpr(LHSExpr);
9505     RHS = CorrectDelayedTyposInExpr(RHSExpr, [Opc, LHS](Expr *E) {
9506       if (Opc != BO_Assign)
9507         return ExprResult(E);
9508       // Avoid correcting the RHS to the same Expr as the LHS.
9509       Decl *D = getDeclFromExpr(E);
9510       return (D && D == getDeclFromExpr(LHS.get())) ? ExprError() : E;
9511     });
9512     if (!LHS.isUsable() || !RHS.isUsable())
9513       return ExprError();
9514   }
9515 
9516   switch (Opc) {
9517   case BO_Assign:
9518     ResultTy = CheckAssignmentOperands(LHS.get(), RHS, OpLoc, QualType());
9519     if (getLangOpts().CPlusPlus &&
9520         LHS.get()->getObjectKind() != OK_ObjCProperty) {
9521       VK = LHS.get()->getValueKind();
9522       OK = LHS.get()->getObjectKind();
9523     }
9524     if (!ResultTy.isNull()) {
9525       DiagnoseSelfAssignment(*this, LHS.get(), RHS.get(), OpLoc);
9526       DiagnoseSelfMove(LHS.get(), RHS.get(), OpLoc);
9527     }
9528     RecordModifiableNonNullParam(*this, LHS.get());
9529     break;
9530   case BO_PtrMemD:
9531   case BO_PtrMemI:
9532     ResultTy = CheckPointerToMemberOperands(LHS, RHS, VK, OpLoc,
9533                                             Opc == BO_PtrMemI);
9534     break;
9535   case BO_Mul:
9536   case BO_Div:
9537     ResultTy = CheckMultiplyDivideOperands(LHS, RHS, OpLoc, false,
9538                                            Opc == BO_Div);
9539     break;
9540   case BO_Rem:
9541     ResultTy = CheckRemainderOperands(LHS, RHS, OpLoc);
9542     break;
9543   case BO_Add:
9544     ResultTy = CheckAdditionOperands(LHS, RHS, OpLoc, Opc);
9545     break;
9546   case BO_Sub:
9547     ResultTy = CheckSubtractionOperands(LHS, RHS, OpLoc);
9548     break;
9549   case BO_Shl:
9550   case BO_Shr:
9551     ResultTy = CheckShiftOperands(LHS, RHS, OpLoc, Opc);
9552     break;
9553   case BO_LE:
9554   case BO_LT:
9555   case BO_GE:
9556   case BO_GT:
9557     ResultTy = CheckCompareOperands(LHS, RHS, OpLoc, Opc, true);
9558     break;
9559   case BO_EQ:
9560   case BO_NE:
9561     ResultTy = CheckCompareOperands(LHS, RHS, OpLoc, Opc, false);
9562     break;
9563   case BO_And:
9564     checkObjCPointerIntrospection(*this, LHS, RHS, OpLoc);
9565   case BO_Xor:
9566   case BO_Or:
9567     ResultTy = CheckBitwiseOperands(LHS, RHS, OpLoc);
9568     break;
9569   case BO_LAnd:
9570   case BO_LOr:
9571     ResultTy = CheckLogicalOperands(LHS, RHS, OpLoc, Opc);
9572     break;
9573   case BO_MulAssign:
9574   case BO_DivAssign:
9575     CompResultTy = CheckMultiplyDivideOperands(LHS, RHS, OpLoc, true,
9576                                                Opc == BO_DivAssign);
9577     CompLHSTy = CompResultTy;
9578     if (!CompResultTy.isNull() && !LHS.isInvalid() && !RHS.isInvalid())
9579       ResultTy = CheckAssignmentOperands(LHS.get(), RHS, OpLoc, CompResultTy);
9580     break;
9581   case BO_RemAssign:
9582     CompResultTy = CheckRemainderOperands(LHS, RHS, OpLoc, true);
9583     CompLHSTy = CompResultTy;
9584     if (!CompResultTy.isNull() && !LHS.isInvalid() && !RHS.isInvalid())
9585       ResultTy = CheckAssignmentOperands(LHS.get(), RHS, OpLoc, CompResultTy);
9586     break;
9587   case BO_AddAssign:
9588     CompResultTy = CheckAdditionOperands(LHS, RHS, OpLoc, Opc, &CompLHSTy);
9589     if (!CompResultTy.isNull() && !LHS.isInvalid() && !RHS.isInvalid())
9590       ResultTy = CheckAssignmentOperands(LHS.get(), RHS, OpLoc, CompResultTy);
9591     break;
9592   case BO_SubAssign:
9593     CompResultTy = CheckSubtractionOperands(LHS, RHS, OpLoc, &CompLHSTy);
9594     if (!CompResultTy.isNull() && !LHS.isInvalid() && !RHS.isInvalid())
9595       ResultTy = CheckAssignmentOperands(LHS.get(), RHS, OpLoc, CompResultTy);
9596     break;
9597   case BO_ShlAssign:
9598   case BO_ShrAssign:
9599     CompResultTy = CheckShiftOperands(LHS, RHS, OpLoc, Opc, true);
9600     CompLHSTy = CompResultTy;
9601     if (!CompResultTy.isNull() && !LHS.isInvalid() && !RHS.isInvalid())
9602       ResultTy = CheckAssignmentOperands(LHS.get(), RHS, OpLoc, CompResultTy);
9603     break;
9604   case BO_AndAssign:
9605   case BO_OrAssign: // fallthrough
9606 	  DiagnoseSelfAssignment(*this, LHS.get(), RHS.get(), OpLoc);
9607   case BO_XorAssign:
9608     CompResultTy = CheckBitwiseOperands(LHS, RHS, OpLoc, true);
9609     CompLHSTy = CompResultTy;
9610     if (!CompResultTy.isNull() && !LHS.isInvalid() && !RHS.isInvalid())
9611       ResultTy = CheckAssignmentOperands(LHS.get(), RHS, OpLoc, CompResultTy);
9612     break;
9613   case BO_Comma:
9614     ResultTy = CheckCommaOperands(*this, LHS, RHS, OpLoc);
9615     if (getLangOpts().CPlusPlus && !RHS.isInvalid()) {
9616       VK = RHS.get()->getValueKind();
9617       OK = RHS.get()->getObjectKind();
9618     }
9619     break;
9620   }
9621   if (ResultTy.isNull() || LHS.isInvalid() || RHS.isInvalid())
9622     return ExprError();
9623 
9624   // Check for array bounds violations for both sides of the BinaryOperator
9625   CheckArrayAccess(LHS.get());
9626   CheckArrayAccess(RHS.get());
9627 
9628   if (const ObjCIsaExpr *OISA = dyn_cast<ObjCIsaExpr>(LHS.get()->IgnoreParenCasts())) {
9629     NamedDecl *ObjectSetClass = LookupSingleName(TUScope,
9630                                                  &Context.Idents.get("object_setClass"),
9631                                                  SourceLocation(), LookupOrdinaryName);
9632     if (ObjectSetClass && isa<ObjCIsaExpr>(LHS.get())) {
9633       SourceLocation RHSLocEnd = PP.getLocForEndOfToken(RHS.get()->getLocEnd());
9634       Diag(LHS.get()->getExprLoc(), diag::warn_objc_isa_assign) <<
9635       FixItHint::CreateInsertion(LHS.get()->getLocStart(), "object_setClass(") <<
9636       FixItHint::CreateReplacement(SourceRange(OISA->getOpLoc(), OpLoc), ",") <<
9637       FixItHint::CreateInsertion(RHSLocEnd, ")");
9638     }
9639     else
9640       Diag(LHS.get()->getExprLoc(), diag::warn_objc_isa_assign);
9641   }
9642   else if (const ObjCIvarRefExpr *OIRE =
9643            dyn_cast<ObjCIvarRefExpr>(LHS.get()->IgnoreParenCasts()))
9644     DiagnoseDirectIsaAccess(*this, OIRE, OpLoc, RHS.get());
9645 
9646   if (CompResultTy.isNull())
9647     return new (Context) BinaryOperator(LHS.get(), RHS.get(), Opc, ResultTy, VK,
9648                                         OK, OpLoc, FPFeatures.fp_contract);
9649   if (getLangOpts().CPlusPlus && LHS.get()->getObjectKind() !=
9650       OK_ObjCProperty) {
9651     VK = VK_LValue;
9652     OK = LHS.get()->getObjectKind();
9653   }
9654   return new (Context) CompoundAssignOperator(
9655       LHS.get(), RHS.get(), Opc, ResultTy, VK, OK, CompLHSTy, CompResultTy,
9656       OpLoc, FPFeatures.fp_contract);
9657 }
9658 
9659 /// DiagnoseBitwisePrecedence - Emit a warning when bitwise and comparison
9660 /// operators are mixed in a way that suggests that the programmer forgot that
9661 /// comparison operators have higher precedence. The most typical example of
9662 /// such code is "flags & 0x0020 != 0", which is equivalent to "flags & 1".
DiagnoseBitwisePrecedence(Sema & Self,BinaryOperatorKind Opc,SourceLocation OpLoc,Expr * LHSExpr,Expr * RHSExpr)9663 static void DiagnoseBitwisePrecedence(Sema &Self, BinaryOperatorKind Opc,
9664                                       SourceLocation OpLoc, Expr *LHSExpr,
9665                                       Expr *RHSExpr) {
9666   BinaryOperator *LHSBO = dyn_cast<BinaryOperator>(LHSExpr);
9667   BinaryOperator *RHSBO = dyn_cast<BinaryOperator>(RHSExpr);
9668 
9669   // Check that one of the sides is a comparison operator.
9670   bool isLeftComp = LHSBO && LHSBO->isComparisonOp();
9671   bool isRightComp = RHSBO && RHSBO->isComparisonOp();
9672   if (!isLeftComp && !isRightComp)
9673     return;
9674 
9675   // Bitwise operations are sometimes used as eager logical ops.
9676   // Don't diagnose this.
9677   bool isLeftBitwise = LHSBO && LHSBO->isBitwiseOp();
9678   bool isRightBitwise = RHSBO && RHSBO->isBitwiseOp();
9679   if ((isLeftComp || isLeftBitwise) && (isRightComp || isRightBitwise))
9680     return;
9681 
9682   SourceRange DiagRange = isLeftComp ? SourceRange(LHSExpr->getLocStart(),
9683                                                    OpLoc)
9684                                      : SourceRange(OpLoc, RHSExpr->getLocEnd());
9685   StringRef OpStr = isLeftComp ? LHSBO->getOpcodeStr() : RHSBO->getOpcodeStr();
9686   SourceRange ParensRange = isLeftComp ?
9687       SourceRange(LHSBO->getRHS()->getLocStart(), RHSExpr->getLocEnd())
9688     : SourceRange(LHSExpr->getLocStart(), RHSBO->getLHS()->getLocEnd());
9689 
9690   Self.Diag(OpLoc, diag::warn_precedence_bitwise_rel)
9691     << DiagRange << BinaryOperator::getOpcodeStr(Opc) << OpStr;
9692   SuggestParentheses(Self, OpLoc,
9693     Self.PDiag(diag::note_precedence_silence) << OpStr,
9694     (isLeftComp ? LHSExpr : RHSExpr)->getSourceRange());
9695   SuggestParentheses(Self, OpLoc,
9696     Self.PDiag(diag::note_precedence_bitwise_first)
9697       << BinaryOperator::getOpcodeStr(Opc),
9698     ParensRange);
9699 }
9700 
9701 /// \brief It accepts a '&' expr that is inside a '|' one.
9702 /// Emit a diagnostic together with a fixit hint that wraps the '&' expression
9703 /// in parentheses.
9704 static void
EmitDiagnosticForBitwiseAndInBitwiseOr(Sema & Self,SourceLocation OpLoc,BinaryOperator * Bop)9705 EmitDiagnosticForBitwiseAndInBitwiseOr(Sema &Self, SourceLocation OpLoc,
9706                                        BinaryOperator *Bop) {
9707   assert(Bop->getOpcode() == BO_And);
9708   Self.Diag(Bop->getOperatorLoc(), diag::warn_bitwise_and_in_bitwise_or)
9709       << Bop->getSourceRange() << OpLoc;
9710   SuggestParentheses(Self, Bop->getOperatorLoc(),
9711     Self.PDiag(diag::note_precedence_silence)
9712       << Bop->getOpcodeStr(),
9713     Bop->getSourceRange());
9714 }
9715 
9716 /// \brief It accepts a '&&' expr that is inside a '||' one.
9717 /// Emit a diagnostic together with a fixit hint that wraps the '&&' expression
9718 /// in parentheses.
9719 static void
EmitDiagnosticForLogicalAndInLogicalOr(Sema & Self,SourceLocation OpLoc,BinaryOperator * Bop)9720 EmitDiagnosticForLogicalAndInLogicalOr(Sema &Self, SourceLocation OpLoc,
9721                                        BinaryOperator *Bop) {
9722   assert(Bop->getOpcode() == BO_LAnd);
9723   Self.Diag(Bop->getOperatorLoc(), diag::warn_logical_and_in_logical_or)
9724       << Bop->getSourceRange() << OpLoc;
9725   SuggestParentheses(Self, Bop->getOperatorLoc(),
9726     Self.PDiag(diag::note_precedence_silence)
9727       << Bop->getOpcodeStr(),
9728     Bop->getSourceRange());
9729 }
9730 
9731 /// \brief Returns true if the given expression can be evaluated as a constant
9732 /// 'true'.
EvaluatesAsTrue(Sema & S,Expr * E)9733 static bool EvaluatesAsTrue(Sema &S, Expr *E) {
9734   bool Res;
9735   return !E->isValueDependent() &&
9736          E->EvaluateAsBooleanCondition(Res, S.getASTContext()) && Res;
9737 }
9738 
9739 /// \brief Returns true if the given expression can be evaluated as a constant
9740 /// 'false'.
EvaluatesAsFalse(Sema & S,Expr * E)9741 static bool EvaluatesAsFalse(Sema &S, Expr *E) {
9742   bool Res;
9743   return !E->isValueDependent() &&
9744          E->EvaluateAsBooleanCondition(Res, S.getASTContext()) && !Res;
9745 }
9746 
9747 /// \brief Look for '&&' in the left hand of a '||' expr.
DiagnoseLogicalAndInLogicalOrLHS(Sema & S,SourceLocation OpLoc,Expr * LHSExpr,Expr * RHSExpr)9748 static void DiagnoseLogicalAndInLogicalOrLHS(Sema &S, SourceLocation OpLoc,
9749                                              Expr *LHSExpr, Expr *RHSExpr) {
9750   if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(LHSExpr)) {
9751     if (Bop->getOpcode() == BO_LAnd) {
9752       // If it's "a && b || 0" don't warn since the precedence doesn't matter.
9753       if (EvaluatesAsFalse(S, RHSExpr))
9754         return;
9755       // If it's "1 && a || b" don't warn since the precedence doesn't matter.
9756       if (!EvaluatesAsTrue(S, Bop->getLHS()))
9757         return EmitDiagnosticForLogicalAndInLogicalOr(S, OpLoc, Bop);
9758     } else if (Bop->getOpcode() == BO_LOr) {
9759       if (BinaryOperator *RBop = dyn_cast<BinaryOperator>(Bop->getRHS())) {
9760         // If it's "a || b && 1 || c" we didn't warn earlier for
9761         // "a || b && 1", but warn now.
9762         if (RBop->getOpcode() == BO_LAnd && EvaluatesAsTrue(S, RBop->getRHS()))
9763           return EmitDiagnosticForLogicalAndInLogicalOr(S, OpLoc, RBop);
9764       }
9765     }
9766   }
9767 }
9768 
9769 /// \brief Look for '&&' in the right hand of a '||' expr.
DiagnoseLogicalAndInLogicalOrRHS(Sema & S,SourceLocation OpLoc,Expr * LHSExpr,Expr * RHSExpr)9770 static void DiagnoseLogicalAndInLogicalOrRHS(Sema &S, SourceLocation OpLoc,
9771                                              Expr *LHSExpr, Expr *RHSExpr) {
9772   if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(RHSExpr)) {
9773     if (Bop->getOpcode() == BO_LAnd) {
9774       // If it's "0 || a && b" don't warn since the precedence doesn't matter.
9775       if (EvaluatesAsFalse(S, LHSExpr))
9776         return;
9777       // If it's "a || b && 1" don't warn since the precedence doesn't matter.
9778       if (!EvaluatesAsTrue(S, Bop->getRHS()))
9779         return EmitDiagnosticForLogicalAndInLogicalOr(S, OpLoc, Bop);
9780     }
9781   }
9782 }
9783 
9784 /// \brief Look for '&' in the left or right hand of a '|' expr.
DiagnoseBitwiseAndInBitwiseOr(Sema & S,SourceLocation OpLoc,Expr * OrArg)9785 static void DiagnoseBitwiseAndInBitwiseOr(Sema &S, SourceLocation OpLoc,
9786                                              Expr *OrArg) {
9787   if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(OrArg)) {
9788     if (Bop->getOpcode() == BO_And)
9789       return EmitDiagnosticForBitwiseAndInBitwiseOr(S, OpLoc, Bop);
9790   }
9791 }
9792 
DiagnoseAdditionInShift(Sema & S,SourceLocation OpLoc,Expr * SubExpr,StringRef Shift)9793 static void DiagnoseAdditionInShift(Sema &S, SourceLocation OpLoc,
9794                                     Expr *SubExpr, StringRef Shift) {
9795   if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(SubExpr)) {
9796     if (Bop->getOpcode() == BO_Add || Bop->getOpcode() == BO_Sub) {
9797       StringRef Op = Bop->getOpcodeStr();
9798       S.Diag(Bop->getOperatorLoc(), diag::warn_addition_in_bitshift)
9799           << Bop->getSourceRange() << OpLoc << Shift << Op;
9800       SuggestParentheses(S, Bop->getOperatorLoc(),
9801           S.PDiag(diag::note_precedence_silence) << Op,
9802           Bop->getSourceRange());
9803     }
9804   }
9805 }
9806 
DiagnoseShiftCompare(Sema & S,SourceLocation OpLoc,Expr * LHSExpr,Expr * RHSExpr)9807 static void DiagnoseShiftCompare(Sema &S, SourceLocation OpLoc,
9808                                  Expr *LHSExpr, Expr *RHSExpr) {
9809   CXXOperatorCallExpr *OCE = dyn_cast<CXXOperatorCallExpr>(LHSExpr);
9810   if (!OCE)
9811     return;
9812 
9813   FunctionDecl *FD = OCE->getDirectCallee();
9814   if (!FD || !FD->isOverloadedOperator())
9815     return;
9816 
9817   OverloadedOperatorKind Kind = FD->getOverloadedOperator();
9818   if (Kind != OO_LessLess && Kind != OO_GreaterGreater)
9819     return;
9820 
9821   S.Diag(OpLoc, diag::warn_overloaded_shift_in_comparison)
9822       << LHSExpr->getSourceRange() << RHSExpr->getSourceRange()
9823       << (Kind == OO_LessLess);
9824   SuggestParentheses(S, OCE->getOperatorLoc(),
9825                      S.PDiag(diag::note_precedence_silence)
9826                          << (Kind == OO_LessLess ? "<<" : ">>"),
9827                      OCE->getSourceRange());
9828   SuggestParentheses(S, OpLoc,
9829                      S.PDiag(diag::note_evaluate_comparison_first),
9830                      SourceRange(OCE->getArg(1)->getLocStart(),
9831                                  RHSExpr->getLocEnd()));
9832 }
9833 
9834 /// DiagnoseBinOpPrecedence - Emit warnings for expressions with tricky
9835 /// precedence.
DiagnoseBinOpPrecedence(Sema & Self,BinaryOperatorKind Opc,SourceLocation OpLoc,Expr * LHSExpr,Expr * RHSExpr)9836 static void DiagnoseBinOpPrecedence(Sema &Self, BinaryOperatorKind Opc,
9837                                     SourceLocation OpLoc, Expr *LHSExpr,
9838                                     Expr *RHSExpr){
9839   // Diagnose "arg1 'bitwise' arg2 'eq' arg3".
9840   if (BinaryOperator::isBitwiseOp(Opc))
9841     DiagnoseBitwisePrecedence(Self, Opc, OpLoc, LHSExpr, RHSExpr);
9842 
9843   // Diagnose "arg1 & arg2 | arg3"
9844   if (Opc == BO_Or && !OpLoc.isMacroID()/* Don't warn in macros. */) {
9845     DiagnoseBitwiseAndInBitwiseOr(Self, OpLoc, LHSExpr);
9846     DiagnoseBitwiseAndInBitwiseOr(Self, OpLoc, RHSExpr);
9847   }
9848 
9849   // Warn about arg1 || arg2 && arg3, as GCC 4.3+ does.
9850   // We don't warn for 'assert(a || b && "bad")' since this is safe.
9851   if (Opc == BO_LOr && !OpLoc.isMacroID()/* Don't warn in macros. */) {
9852     DiagnoseLogicalAndInLogicalOrLHS(Self, OpLoc, LHSExpr, RHSExpr);
9853     DiagnoseLogicalAndInLogicalOrRHS(Self, OpLoc, LHSExpr, RHSExpr);
9854   }
9855 
9856   if ((Opc == BO_Shl && LHSExpr->getType()->isIntegralType(Self.getASTContext()))
9857       || Opc == BO_Shr) {
9858     StringRef Shift = BinaryOperator::getOpcodeStr(Opc);
9859     DiagnoseAdditionInShift(Self, OpLoc, LHSExpr, Shift);
9860     DiagnoseAdditionInShift(Self, OpLoc, RHSExpr, Shift);
9861   }
9862 
9863   // Warn on overloaded shift operators and comparisons, such as:
9864   // cout << 5 == 4;
9865   if (BinaryOperator::isComparisonOp(Opc))
9866     DiagnoseShiftCompare(Self, OpLoc, LHSExpr, RHSExpr);
9867 }
9868 
9869 // Binary Operators.  'Tok' is the token for the operator.
ActOnBinOp(Scope * S,SourceLocation TokLoc,tok::TokenKind Kind,Expr * LHSExpr,Expr * RHSExpr)9870 ExprResult Sema::ActOnBinOp(Scope *S, SourceLocation TokLoc,
9871                             tok::TokenKind Kind,
9872                             Expr *LHSExpr, Expr *RHSExpr) {
9873   BinaryOperatorKind Opc = ConvertTokenKindToBinaryOpcode(Kind);
9874   assert(LHSExpr && "ActOnBinOp(): missing left expression");
9875   assert(RHSExpr && "ActOnBinOp(): missing right expression");
9876 
9877   // Emit warnings for tricky precedence issues, e.g. "bitfield & 0x4 == 0"
9878   DiagnoseBinOpPrecedence(*this, Opc, TokLoc, LHSExpr, RHSExpr);
9879 
9880   return BuildBinOp(S, TokLoc, Opc, LHSExpr, RHSExpr);
9881 }
9882 
9883 /// Build an overloaded binary operator expression in the given scope.
BuildOverloadedBinOp(Sema & S,Scope * Sc,SourceLocation OpLoc,BinaryOperatorKind Opc,Expr * LHS,Expr * RHS)9884 static ExprResult BuildOverloadedBinOp(Sema &S, Scope *Sc, SourceLocation OpLoc,
9885                                        BinaryOperatorKind Opc,
9886                                        Expr *LHS, Expr *RHS) {
9887   // Find all of the overloaded operators visible from this
9888   // point. We perform both an operator-name lookup from the local
9889   // scope and an argument-dependent lookup based on the types of
9890   // the arguments.
9891   UnresolvedSet<16> Functions;
9892   OverloadedOperatorKind OverOp
9893     = BinaryOperator::getOverloadedOperator(Opc);
9894   if (Sc && OverOp != OO_None && OverOp != OO_Equal)
9895     S.LookupOverloadedOperatorName(OverOp, Sc, LHS->getType(),
9896                                    RHS->getType(), Functions);
9897 
9898   // Build the (potentially-overloaded, potentially-dependent)
9899   // binary operation.
9900   return S.CreateOverloadedBinOp(OpLoc, Opc, Functions, LHS, RHS);
9901 }
9902 
BuildBinOp(Scope * S,SourceLocation OpLoc,BinaryOperatorKind Opc,Expr * LHSExpr,Expr * RHSExpr)9903 ExprResult Sema::BuildBinOp(Scope *S, SourceLocation OpLoc,
9904                             BinaryOperatorKind Opc,
9905                             Expr *LHSExpr, Expr *RHSExpr) {
9906   // We want to end up calling one of checkPseudoObjectAssignment
9907   // (if the LHS is a pseudo-object), BuildOverloadedBinOp (if
9908   // both expressions are overloadable or either is type-dependent),
9909   // or CreateBuiltinBinOp (in any other case).  We also want to get
9910   // any placeholder types out of the way.
9911 
9912   // Handle pseudo-objects in the LHS.
9913   if (const BuiltinType *pty = LHSExpr->getType()->getAsPlaceholderType()) {
9914     // Assignments with a pseudo-object l-value need special analysis.
9915     if (pty->getKind() == BuiltinType::PseudoObject &&
9916         BinaryOperator::isAssignmentOp(Opc))
9917       return checkPseudoObjectAssignment(S, OpLoc, Opc, LHSExpr, RHSExpr);
9918 
9919     // Don't resolve overloads if the other type is overloadable.
9920     if (pty->getKind() == BuiltinType::Overload) {
9921       // We can't actually test that if we still have a placeholder,
9922       // though.  Fortunately, none of the exceptions we see in that
9923       // code below are valid when the LHS is an overload set.  Note
9924       // that an overload set can be dependently-typed, but it never
9925       // instantiates to having an overloadable type.
9926       ExprResult resolvedRHS = CheckPlaceholderExpr(RHSExpr);
9927       if (resolvedRHS.isInvalid()) return ExprError();
9928       RHSExpr = resolvedRHS.get();
9929 
9930       if (RHSExpr->isTypeDependent() ||
9931           RHSExpr->getType()->isOverloadableType())
9932         return BuildOverloadedBinOp(*this, S, OpLoc, Opc, LHSExpr, RHSExpr);
9933     }
9934 
9935     ExprResult LHS = CheckPlaceholderExpr(LHSExpr);
9936     if (LHS.isInvalid()) return ExprError();
9937     LHSExpr = LHS.get();
9938   }
9939 
9940   // Handle pseudo-objects in the RHS.
9941   if (const BuiltinType *pty = RHSExpr->getType()->getAsPlaceholderType()) {
9942     // An overload in the RHS can potentially be resolved by the type
9943     // being assigned to.
9944     if (Opc == BO_Assign && pty->getKind() == BuiltinType::Overload) {
9945       if (LHSExpr->isTypeDependent() || RHSExpr->isTypeDependent())
9946         return BuildOverloadedBinOp(*this, S, OpLoc, Opc, LHSExpr, RHSExpr);
9947 
9948       if (LHSExpr->getType()->isOverloadableType())
9949         return BuildOverloadedBinOp(*this, S, OpLoc, Opc, LHSExpr, RHSExpr);
9950 
9951       return CreateBuiltinBinOp(OpLoc, Opc, LHSExpr, RHSExpr);
9952     }
9953 
9954     // Don't resolve overloads if the other type is overloadable.
9955     if (pty->getKind() == BuiltinType::Overload &&
9956         LHSExpr->getType()->isOverloadableType())
9957       return BuildOverloadedBinOp(*this, S, OpLoc, Opc, LHSExpr, RHSExpr);
9958 
9959     ExprResult resolvedRHS = CheckPlaceholderExpr(RHSExpr);
9960     if (!resolvedRHS.isUsable()) return ExprError();
9961     RHSExpr = resolvedRHS.get();
9962   }
9963 
9964   if (getLangOpts().CPlusPlus) {
9965     // If either expression is type-dependent, always build an
9966     // overloaded op.
9967     if (LHSExpr->isTypeDependent() || RHSExpr->isTypeDependent())
9968       return BuildOverloadedBinOp(*this, S, OpLoc, Opc, LHSExpr, RHSExpr);
9969 
9970     // Otherwise, build an overloaded op if either expression has an
9971     // overloadable type.
9972     if (LHSExpr->getType()->isOverloadableType() ||
9973         RHSExpr->getType()->isOverloadableType())
9974       return BuildOverloadedBinOp(*this, S, OpLoc, Opc, LHSExpr, RHSExpr);
9975   }
9976 
9977   // Build a built-in binary operation.
9978   return CreateBuiltinBinOp(OpLoc, Opc, LHSExpr, RHSExpr);
9979 }
9980 
CreateBuiltinUnaryOp(SourceLocation OpLoc,UnaryOperatorKind Opc,Expr * InputExpr)9981 ExprResult Sema::CreateBuiltinUnaryOp(SourceLocation OpLoc,
9982                                       UnaryOperatorKind Opc,
9983                                       Expr *InputExpr) {
9984   ExprResult Input = InputExpr;
9985   ExprValueKind VK = VK_RValue;
9986   ExprObjectKind OK = OK_Ordinary;
9987   QualType resultType;
9988   switch (Opc) {
9989   case UO_PreInc:
9990   case UO_PreDec:
9991   case UO_PostInc:
9992   case UO_PostDec:
9993     resultType = CheckIncrementDecrementOperand(*this, Input.get(), VK, OK,
9994                                                 OpLoc,
9995                                                 Opc == UO_PreInc ||
9996                                                 Opc == UO_PostInc,
9997                                                 Opc == UO_PreInc ||
9998                                                 Opc == UO_PreDec);
9999     break;
10000   case UO_AddrOf:
10001     resultType = CheckAddressOfOperand(Input, OpLoc);
10002     RecordModifiableNonNullParam(*this, InputExpr);
10003     break;
10004   case UO_Deref: {
10005     Input = DefaultFunctionArrayLvalueConversion(Input.get());
10006     if (Input.isInvalid()) return ExprError();
10007     resultType = CheckIndirectionOperand(*this, Input.get(), VK, OpLoc);
10008     break;
10009   }
10010   case UO_Plus:
10011   case UO_Minus:
10012     Input = UsualUnaryConversions(Input.get());
10013     if (Input.isInvalid()) return ExprError();
10014     resultType = Input.get()->getType();
10015     if (resultType->isDependentType())
10016       break;
10017     if (resultType->isArithmeticType() || // C99 6.5.3.3p1
10018         resultType->isVectorType())
10019       break;
10020     else if (getLangOpts().CPlusPlus && // C++ [expr.unary.op]p6
10021              Opc == UO_Plus &&
10022              resultType->isPointerType())
10023       break;
10024 
10025     return ExprError(Diag(OpLoc, diag::err_typecheck_unary_expr)
10026       << resultType << Input.get()->getSourceRange());
10027 
10028   case UO_Not: // bitwise complement
10029     Input = UsualUnaryConversions(Input.get());
10030     if (Input.isInvalid())
10031       return ExprError();
10032     resultType = Input.get()->getType();
10033     if (resultType->isDependentType())
10034       break;
10035     // C99 6.5.3.3p1. We allow complex int and float as a GCC extension.
10036     if (resultType->isComplexType() || resultType->isComplexIntegerType())
10037       // C99 does not support '~' for complex conjugation.
10038       Diag(OpLoc, diag::ext_integer_complement_complex)
10039           << resultType << Input.get()->getSourceRange();
10040     else if (resultType->hasIntegerRepresentation())
10041       break;
10042     else if (resultType->isExtVectorType()) {
10043       if (Context.getLangOpts().OpenCL) {
10044         // OpenCL v1.1 s6.3.f: The bitwise operator not (~) does not operate
10045         // on vector float types.
10046         QualType T = resultType->getAs<ExtVectorType>()->getElementType();
10047         if (!T->isIntegerType())
10048           return ExprError(Diag(OpLoc, diag::err_typecheck_unary_expr)
10049                            << resultType << Input.get()->getSourceRange());
10050       }
10051       break;
10052     } else {
10053       return ExprError(Diag(OpLoc, diag::err_typecheck_unary_expr)
10054                        << resultType << Input.get()->getSourceRange());
10055     }
10056     break;
10057 
10058   case UO_LNot: // logical negation
10059     // Unlike +/-/~, integer promotions aren't done here (C99 6.5.3.3p5).
10060     Input = DefaultFunctionArrayLvalueConversion(Input.get());
10061     if (Input.isInvalid()) return ExprError();
10062     resultType = Input.get()->getType();
10063 
10064     // Though we still have to promote half FP to float...
10065     if (resultType->isHalfType() && !Context.getLangOpts().NativeHalfType) {
10066       Input = ImpCastExprToType(Input.get(), Context.FloatTy, CK_FloatingCast).get();
10067       resultType = Context.FloatTy;
10068     }
10069 
10070     if (resultType->isDependentType())
10071       break;
10072     if (resultType->isScalarType() && !isScopedEnumerationType(resultType)) {
10073       // C99 6.5.3.3p1: ok, fallthrough;
10074       if (Context.getLangOpts().CPlusPlus) {
10075         // C++03 [expr.unary.op]p8, C++0x [expr.unary.op]p9:
10076         // operand contextually converted to bool.
10077         Input = ImpCastExprToType(Input.get(), Context.BoolTy,
10078                                   ScalarTypeToBooleanCastKind(resultType));
10079       } else if (Context.getLangOpts().OpenCL &&
10080                  Context.getLangOpts().OpenCLVersion < 120) {
10081         // OpenCL v1.1 6.3.h: The logical operator not (!) does not
10082         // operate on scalar float types.
10083         if (!resultType->isIntegerType())
10084           return ExprError(Diag(OpLoc, diag::err_typecheck_unary_expr)
10085                            << resultType << Input.get()->getSourceRange());
10086       }
10087     } else if (resultType->isExtVectorType()) {
10088       if (Context.getLangOpts().OpenCL &&
10089           Context.getLangOpts().OpenCLVersion < 120) {
10090         // OpenCL v1.1 6.3.h: The logical operator not (!) does not
10091         // operate on vector float types.
10092         QualType T = resultType->getAs<ExtVectorType>()->getElementType();
10093         if (!T->isIntegerType())
10094           return ExprError(Diag(OpLoc, diag::err_typecheck_unary_expr)
10095                            << resultType << Input.get()->getSourceRange());
10096       }
10097       // Vector logical not returns the signed variant of the operand type.
10098       resultType = GetSignedVectorType(resultType);
10099       break;
10100     } else {
10101       return ExprError(Diag(OpLoc, diag::err_typecheck_unary_expr)
10102         << resultType << Input.get()->getSourceRange());
10103     }
10104 
10105     // LNot always has type int. C99 6.5.3.3p5.
10106     // In C++, it's bool. C++ 5.3.1p8
10107     resultType = Context.getLogicalOperationType();
10108     break;
10109   case UO_Real:
10110   case UO_Imag:
10111     resultType = CheckRealImagOperand(*this, Input, OpLoc, Opc == UO_Real);
10112     // _Real maps ordinary l-values into ordinary l-values. _Imag maps ordinary
10113     // complex l-values to ordinary l-values and all other values to r-values.
10114     if (Input.isInvalid()) return ExprError();
10115     if (Opc == UO_Real || Input.get()->getType()->isAnyComplexType()) {
10116       if (Input.get()->getValueKind() != VK_RValue &&
10117           Input.get()->getObjectKind() == OK_Ordinary)
10118         VK = Input.get()->getValueKind();
10119     } else if (!getLangOpts().CPlusPlus) {
10120       // In C, a volatile scalar is read by __imag. In C++, it is not.
10121       Input = DefaultLvalueConversion(Input.get());
10122     }
10123     break;
10124   case UO_Extension:
10125     resultType = Input.get()->getType();
10126     VK = Input.get()->getValueKind();
10127     OK = Input.get()->getObjectKind();
10128     break;
10129   }
10130   if (resultType.isNull() || Input.isInvalid())
10131     return ExprError();
10132 
10133   // Check for array bounds violations in the operand of the UnaryOperator,
10134   // except for the '*' and '&' operators that have to be handled specially
10135   // by CheckArrayAccess (as there are special cases like &array[arraysize]
10136   // that are explicitly defined as valid by the standard).
10137   if (Opc != UO_AddrOf && Opc != UO_Deref)
10138     CheckArrayAccess(Input.get());
10139 
10140   return new (Context)
10141       UnaryOperator(Input.get(), Opc, resultType, VK, OK, OpLoc);
10142 }
10143 
10144 /// \brief Determine whether the given expression is a qualified member
10145 /// access expression, of a form that could be turned into a pointer to member
10146 /// with the address-of operator.
isQualifiedMemberAccess(Expr * E)10147 static bool isQualifiedMemberAccess(Expr *E) {
10148   if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
10149     if (!DRE->getQualifier())
10150       return false;
10151 
10152     ValueDecl *VD = DRE->getDecl();
10153     if (!VD->isCXXClassMember())
10154       return false;
10155 
10156     if (isa<FieldDecl>(VD) || isa<IndirectFieldDecl>(VD))
10157       return true;
10158     if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(VD))
10159       return Method->isInstance();
10160 
10161     return false;
10162   }
10163 
10164   if (UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(E)) {
10165     if (!ULE->getQualifier())
10166       return false;
10167 
10168     for (UnresolvedLookupExpr::decls_iterator D = ULE->decls_begin(),
10169                                            DEnd = ULE->decls_end();
10170          D != DEnd; ++D) {
10171       if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(*D)) {
10172         if (Method->isInstance())
10173           return true;
10174       } else {
10175         // Overload set does not contain methods.
10176         break;
10177       }
10178     }
10179 
10180     return false;
10181   }
10182 
10183   return false;
10184 }
10185 
BuildUnaryOp(Scope * S,SourceLocation OpLoc,UnaryOperatorKind Opc,Expr * Input)10186 ExprResult Sema::BuildUnaryOp(Scope *S, SourceLocation OpLoc,
10187                               UnaryOperatorKind Opc, Expr *Input) {
10188   // First things first: handle placeholders so that the
10189   // overloaded-operator check considers the right type.
10190   if (const BuiltinType *pty = Input->getType()->getAsPlaceholderType()) {
10191     // Increment and decrement of pseudo-object references.
10192     if (pty->getKind() == BuiltinType::PseudoObject &&
10193         UnaryOperator::isIncrementDecrementOp(Opc))
10194       return checkPseudoObjectIncDec(S, OpLoc, Opc, Input);
10195 
10196     // extension is always a builtin operator.
10197     if (Opc == UO_Extension)
10198       return CreateBuiltinUnaryOp(OpLoc, Opc, Input);
10199 
10200     // & gets special logic for several kinds of placeholder.
10201     // The builtin code knows what to do.
10202     if (Opc == UO_AddrOf &&
10203         (pty->getKind() == BuiltinType::Overload ||
10204          pty->getKind() == BuiltinType::UnknownAny ||
10205          pty->getKind() == BuiltinType::BoundMember))
10206       return CreateBuiltinUnaryOp(OpLoc, Opc, Input);
10207 
10208     // Anything else needs to be handled now.
10209     ExprResult Result = CheckPlaceholderExpr(Input);
10210     if (Result.isInvalid()) return ExprError();
10211     Input = Result.get();
10212   }
10213 
10214   if (getLangOpts().CPlusPlus && Input->getType()->isOverloadableType() &&
10215       UnaryOperator::getOverloadedOperator(Opc) != OO_None &&
10216       !(Opc == UO_AddrOf && isQualifiedMemberAccess(Input))) {
10217     // Find all of the overloaded operators visible from this
10218     // point. We perform both an operator-name lookup from the local
10219     // scope and an argument-dependent lookup based on the types of
10220     // the arguments.
10221     UnresolvedSet<16> Functions;
10222     OverloadedOperatorKind OverOp = UnaryOperator::getOverloadedOperator(Opc);
10223     if (S && OverOp != OO_None)
10224       LookupOverloadedOperatorName(OverOp, S, Input->getType(), QualType(),
10225                                    Functions);
10226 
10227     return CreateOverloadedUnaryOp(OpLoc, Opc, Functions, Input);
10228   }
10229 
10230   return CreateBuiltinUnaryOp(OpLoc, Opc, Input);
10231 }
10232 
10233 // Unary Operators.  'Tok' is the token for the operator.
ActOnUnaryOp(Scope * S,SourceLocation OpLoc,tok::TokenKind Op,Expr * Input)10234 ExprResult Sema::ActOnUnaryOp(Scope *S, SourceLocation OpLoc,
10235                               tok::TokenKind Op, Expr *Input) {
10236   return BuildUnaryOp(S, OpLoc, ConvertTokenKindToUnaryOpcode(Op), Input);
10237 }
10238 
10239 /// ActOnAddrLabel - Parse the GNU address of label extension: "&&foo".
ActOnAddrLabel(SourceLocation OpLoc,SourceLocation LabLoc,LabelDecl * TheDecl)10240 ExprResult Sema::ActOnAddrLabel(SourceLocation OpLoc, SourceLocation LabLoc,
10241                                 LabelDecl *TheDecl) {
10242   TheDecl->markUsed(Context);
10243   // Create the AST node.  The address of a label always has type 'void*'.
10244   return new (Context) AddrLabelExpr(OpLoc, LabLoc, TheDecl,
10245                                      Context.getPointerType(Context.VoidTy));
10246 }
10247 
10248 /// Given the last statement in a statement-expression, check whether
10249 /// the result is a producing expression (like a call to an
10250 /// ns_returns_retained function) and, if so, rebuild it to hoist the
10251 /// release out of the full-expression.  Otherwise, return null.
10252 /// Cannot fail.
maybeRebuildARCConsumingStmt(Stmt * Statement)10253 static Expr *maybeRebuildARCConsumingStmt(Stmt *Statement) {
10254   // Should always be wrapped with one of these.
10255   ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(Statement);
10256   if (!cleanups) return nullptr;
10257 
10258   ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(cleanups->getSubExpr());
10259   if (!cast || cast->getCastKind() != CK_ARCConsumeObject)
10260     return nullptr;
10261 
10262   // Splice out the cast.  This shouldn't modify any interesting
10263   // features of the statement.
10264   Expr *producer = cast->getSubExpr();
10265   assert(producer->getType() == cast->getType());
10266   assert(producer->getValueKind() == cast->getValueKind());
10267   cleanups->setSubExpr(producer);
10268   return cleanups;
10269 }
10270 
ActOnStartStmtExpr()10271 void Sema::ActOnStartStmtExpr() {
10272   PushExpressionEvaluationContext(ExprEvalContexts.back().Context);
10273 }
10274 
ActOnStmtExprError()10275 void Sema::ActOnStmtExprError() {
10276   // Note that function is also called by TreeTransform when leaving a
10277   // StmtExpr scope without rebuilding anything.
10278 
10279   DiscardCleanupsInEvaluationContext();
10280   PopExpressionEvaluationContext();
10281 }
10282 
10283 ExprResult
ActOnStmtExpr(SourceLocation LPLoc,Stmt * SubStmt,SourceLocation RPLoc)10284 Sema::ActOnStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,
10285                     SourceLocation RPLoc) { // "({..})"
10286   assert(SubStmt && isa<CompoundStmt>(SubStmt) && "Invalid action invocation!");
10287   CompoundStmt *Compound = cast<CompoundStmt>(SubStmt);
10288 
10289   if (hasAnyUnrecoverableErrorsInThisFunction())
10290     DiscardCleanupsInEvaluationContext();
10291   assert(!ExprNeedsCleanups && "cleanups within StmtExpr not correctly bound!");
10292   PopExpressionEvaluationContext();
10293 
10294   // FIXME: there are a variety of strange constraints to enforce here, for
10295   // example, it is not possible to goto into a stmt expression apparently.
10296   // More semantic analysis is needed.
10297 
10298   // If there are sub-stmts in the compound stmt, take the type of the last one
10299   // as the type of the stmtexpr.
10300   QualType Ty = Context.VoidTy;
10301   bool StmtExprMayBindToTemp = false;
10302   if (!Compound->body_empty()) {
10303     Stmt *LastStmt = Compound->body_back();
10304     LabelStmt *LastLabelStmt = nullptr;
10305     // If LastStmt is a label, skip down through into the body.
10306     while (LabelStmt *Label = dyn_cast<LabelStmt>(LastStmt)) {
10307       LastLabelStmt = Label;
10308       LastStmt = Label->getSubStmt();
10309     }
10310 
10311     if (Expr *LastE = dyn_cast<Expr>(LastStmt)) {
10312       // Do function/array conversion on the last expression, but not
10313       // lvalue-to-rvalue.  However, initialize an unqualified type.
10314       ExprResult LastExpr = DefaultFunctionArrayConversion(LastE);
10315       if (LastExpr.isInvalid())
10316         return ExprError();
10317       Ty = LastExpr.get()->getType().getUnqualifiedType();
10318 
10319       if (!Ty->isDependentType() && !LastExpr.get()->isTypeDependent()) {
10320         // In ARC, if the final expression ends in a consume, splice
10321         // the consume out and bind it later.  In the alternate case
10322         // (when dealing with a retainable type), the result
10323         // initialization will create a produce.  In both cases the
10324         // result will be +1, and we'll need to balance that out with
10325         // a bind.
10326         if (Expr *rebuiltLastStmt
10327               = maybeRebuildARCConsumingStmt(LastExpr.get())) {
10328           LastExpr = rebuiltLastStmt;
10329         } else {
10330           LastExpr = PerformCopyInitialization(
10331                             InitializedEntity::InitializeResult(LPLoc,
10332                                                                 Ty,
10333                                                                 false),
10334                                                    SourceLocation(),
10335                                                LastExpr);
10336         }
10337 
10338         if (LastExpr.isInvalid())
10339           return ExprError();
10340         if (LastExpr.get() != nullptr) {
10341           if (!LastLabelStmt)
10342             Compound->setLastStmt(LastExpr.get());
10343           else
10344             LastLabelStmt->setSubStmt(LastExpr.get());
10345           StmtExprMayBindToTemp = true;
10346         }
10347       }
10348     }
10349   }
10350 
10351   // FIXME: Check that expression type is complete/non-abstract; statement
10352   // expressions are not lvalues.
10353   Expr *ResStmtExpr = new (Context) StmtExpr(Compound, Ty, LPLoc, RPLoc);
10354   if (StmtExprMayBindToTemp)
10355     return MaybeBindToTemporary(ResStmtExpr);
10356   return ResStmtExpr;
10357 }
10358 
BuildBuiltinOffsetOf(SourceLocation BuiltinLoc,TypeSourceInfo * TInfo,OffsetOfComponent * CompPtr,unsigned NumComponents,SourceLocation RParenLoc)10359 ExprResult Sema::BuildBuiltinOffsetOf(SourceLocation BuiltinLoc,
10360                                       TypeSourceInfo *TInfo,
10361                                       OffsetOfComponent *CompPtr,
10362                                       unsigned NumComponents,
10363                                       SourceLocation RParenLoc) {
10364   QualType ArgTy = TInfo->getType();
10365   bool Dependent = ArgTy->isDependentType();
10366   SourceRange TypeRange = TInfo->getTypeLoc().getLocalSourceRange();
10367 
10368   // We must have at least one component that refers to the type, and the first
10369   // one is known to be a field designator.  Verify that the ArgTy represents
10370   // a struct/union/class.
10371   if (!Dependent && !ArgTy->isRecordType())
10372     return ExprError(Diag(BuiltinLoc, diag::err_offsetof_record_type)
10373                        << ArgTy << TypeRange);
10374 
10375   // Type must be complete per C99 7.17p3 because a declaring a variable
10376   // with an incomplete type would be ill-formed.
10377   if (!Dependent
10378       && RequireCompleteType(BuiltinLoc, ArgTy,
10379                              diag::err_offsetof_incomplete_type, TypeRange))
10380     return ExprError();
10381 
10382   // offsetof with non-identifier designators (e.g. "offsetof(x, a.b[c])") are a
10383   // GCC extension, diagnose them.
10384   // FIXME: This diagnostic isn't actually visible because the location is in
10385   // a system header!
10386   if (NumComponents != 1)
10387     Diag(BuiltinLoc, diag::ext_offsetof_extended_field_designator)
10388       << SourceRange(CompPtr[1].LocStart, CompPtr[NumComponents-1].LocEnd);
10389 
10390   bool DidWarnAboutNonPOD = false;
10391   QualType CurrentType = ArgTy;
10392   typedef OffsetOfExpr::OffsetOfNode OffsetOfNode;
10393   SmallVector<OffsetOfNode, 4> Comps;
10394   SmallVector<Expr*, 4> Exprs;
10395   for (unsigned i = 0; i != NumComponents; ++i) {
10396     const OffsetOfComponent &OC = CompPtr[i];
10397     if (OC.isBrackets) {
10398       // Offset of an array sub-field.  TODO: Should we allow vector elements?
10399       if (!CurrentType->isDependentType()) {
10400         const ArrayType *AT = Context.getAsArrayType(CurrentType);
10401         if(!AT)
10402           return ExprError(Diag(OC.LocEnd, diag::err_offsetof_array_type)
10403                            << CurrentType);
10404         CurrentType = AT->getElementType();
10405       } else
10406         CurrentType = Context.DependentTy;
10407 
10408       ExprResult IdxRval = DefaultLvalueConversion(static_cast<Expr*>(OC.U.E));
10409       if (IdxRval.isInvalid())
10410         return ExprError();
10411       Expr *Idx = IdxRval.get();
10412 
10413       // The expression must be an integral expression.
10414       // FIXME: An integral constant expression?
10415       if (!Idx->isTypeDependent() && !Idx->isValueDependent() &&
10416           !Idx->getType()->isIntegerType())
10417         return ExprError(Diag(Idx->getLocStart(),
10418                               diag::err_typecheck_subscript_not_integer)
10419                          << Idx->getSourceRange());
10420 
10421       // Record this array index.
10422       Comps.push_back(OffsetOfNode(OC.LocStart, Exprs.size(), OC.LocEnd));
10423       Exprs.push_back(Idx);
10424       continue;
10425     }
10426 
10427     // Offset of a field.
10428     if (CurrentType->isDependentType()) {
10429       // We have the offset of a field, but we can't look into the dependent
10430       // type. Just record the identifier of the field.
10431       Comps.push_back(OffsetOfNode(OC.LocStart, OC.U.IdentInfo, OC.LocEnd));
10432       CurrentType = Context.DependentTy;
10433       continue;
10434     }
10435 
10436     // We need to have a complete type to look into.
10437     if (RequireCompleteType(OC.LocStart, CurrentType,
10438                             diag::err_offsetof_incomplete_type))
10439       return ExprError();
10440 
10441     // Look for the designated field.
10442     const RecordType *RC = CurrentType->getAs<RecordType>();
10443     if (!RC)
10444       return ExprError(Diag(OC.LocEnd, diag::err_offsetof_record_type)
10445                        << CurrentType);
10446     RecordDecl *RD = RC->getDecl();
10447 
10448     // C++ [lib.support.types]p5:
10449     //   The macro offsetof accepts a restricted set of type arguments in this
10450     //   International Standard. type shall be a POD structure or a POD union
10451     //   (clause 9).
10452     // C++11 [support.types]p4:
10453     //   If type is not a standard-layout class (Clause 9), the results are
10454     //   undefined.
10455     if (CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
10456       bool IsSafe = LangOpts.CPlusPlus11? CRD->isStandardLayout() : CRD->isPOD();
10457       unsigned DiagID =
10458         LangOpts.CPlusPlus11? diag::ext_offsetof_non_standardlayout_type
10459                             : diag::ext_offsetof_non_pod_type;
10460 
10461       if (!IsSafe && !DidWarnAboutNonPOD &&
10462           DiagRuntimeBehavior(BuiltinLoc, nullptr,
10463                               PDiag(DiagID)
10464                               << SourceRange(CompPtr[0].LocStart, OC.LocEnd)
10465                               << CurrentType))
10466         DidWarnAboutNonPOD = true;
10467     }
10468 
10469     // Look for the field.
10470     LookupResult R(*this, OC.U.IdentInfo, OC.LocStart, LookupMemberName);
10471     LookupQualifiedName(R, RD);
10472     FieldDecl *MemberDecl = R.getAsSingle<FieldDecl>();
10473     IndirectFieldDecl *IndirectMemberDecl = nullptr;
10474     if (!MemberDecl) {
10475       if ((IndirectMemberDecl = R.getAsSingle<IndirectFieldDecl>()))
10476         MemberDecl = IndirectMemberDecl->getAnonField();
10477     }
10478 
10479     if (!MemberDecl)
10480       return ExprError(Diag(BuiltinLoc, diag::err_no_member)
10481                        << OC.U.IdentInfo << RD << SourceRange(OC.LocStart,
10482                                                               OC.LocEnd));
10483 
10484     // C99 7.17p3:
10485     //   (If the specified member is a bit-field, the behavior is undefined.)
10486     //
10487     // We diagnose this as an error.
10488     if (MemberDecl->isBitField()) {
10489       Diag(OC.LocEnd, diag::err_offsetof_bitfield)
10490         << MemberDecl->getDeclName()
10491         << SourceRange(BuiltinLoc, RParenLoc);
10492       Diag(MemberDecl->getLocation(), diag::note_bitfield_decl);
10493       return ExprError();
10494     }
10495 
10496     RecordDecl *Parent = MemberDecl->getParent();
10497     if (IndirectMemberDecl)
10498       Parent = cast<RecordDecl>(IndirectMemberDecl->getDeclContext());
10499 
10500     // If the member was found in a base class, introduce OffsetOfNodes for
10501     // the base class indirections.
10502     CXXBasePaths Paths;
10503     if (IsDerivedFrom(CurrentType, Context.getTypeDeclType(Parent), Paths)) {
10504       if (Paths.getDetectedVirtual()) {
10505         Diag(OC.LocEnd, diag::err_offsetof_field_of_virtual_base)
10506           << MemberDecl->getDeclName()
10507           << SourceRange(BuiltinLoc, RParenLoc);
10508         return ExprError();
10509       }
10510 
10511       CXXBasePath &Path = Paths.front();
10512       for (CXXBasePath::iterator B = Path.begin(), BEnd = Path.end();
10513            B != BEnd; ++B)
10514         Comps.push_back(OffsetOfNode(B->Base));
10515     }
10516 
10517     if (IndirectMemberDecl) {
10518       for (auto *FI : IndirectMemberDecl->chain()) {
10519         assert(isa<FieldDecl>(FI));
10520         Comps.push_back(OffsetOfNode(OC.LocStart,
10521                                      cast<FieldDecl>(FI), OC.LocEnd));
10522       }
10523     } else
10524       Comps.push_back(OffsetOfNode(OC.LocStart, MemberDecl, OC.LocEnd));
10525 
10526     CurrentType = MemberDecl->getType().getNonReferenceType();
10527   }
10528 
10529   return OffsetOfExpr::Create(Context, Context.getSizeType(), BuiltinLoc, TInfo,
10530                               Comps, Exprs, RParenLoc);
10531 }
10532 
ActOnBuiltinOffsetOf(Scope * S,SourceLocation BuiltinLoc,SourceLocation TypeLoc,ParsedType ParsedArgTy,OffsetOfComponent * CompPtr,unsigned NumComponents,SourceLocation RParenLoc)10533 ExprResult Sema::ActOnBuiltinOffsetOf(Scope *S,
10534                                       SourceLocation BuiltinLoc,
10535                                       SourceLocation TypeLoc,
10536                                       ParsedType ParsedArgTy,
10537                                       OffsetOfComponent *CompPtr,
10538                                       unsigned NumComponents,
10539                                       SourceLocation RParenLoc) {
10540 
10541   TypeSourceInfo *ArgTInfo;
10542   QualType ArgTy = GetTypeFromParser(ParsedArgTy, &ArgTInfo);
10543   if (ArgTy.isNull())
10544     return ExprError();
10545 
10546   if (!ArgTInfo)
10547     ArgTInfo = Context.getTrivialTypeSourceInfo(ArgTy, TypeLoc);
10548 
10549   return BuildBuiltinOffsetOf(BuiltinLoc, ArgTInfo, CompPtr, NumComponents,
10550                               RParenLoc);
10551 }
10552 
10553 
ActOnChooseExpr(SourceLocation BuiltinLoc,Expr * CondExpr,Expr * LHSExpr,Expr * RHSExpr,SourceLocation RPLoc)10554 ExprResult Sema::ActOnChooseExpr(SourceLocation BuiltinLoc,
10555                                  Expr *CondExpr,
10556                                  Expr *LHSExpr, Expr *RHSExpr,
10557                                  SourceLocation RPLoc) {
10558   assert((CondExpr && LHSExpr && RHSExpr) && "Missing type argument(s)");
10559 
10560   ExprValueKind VK = VK_RValue;
10561   ExprObjectKind OK = OK_Ordinary;
10562   QualType resType;
10563   bool ValueDependent = false;
10564   bool CondIsTrue = false;
10565   if (CondExpr->isTypeDependent() || CondExpr->isValueDependent()) {
10566     resType = Context.DependentTy;
10567     ValueDependent = true;
10568   } else {
10569     // The conditional expression is required to be a constant expression.
10570     llvm::APSInt condEval(32);
10571     ExprResult CondICE
10572       = VerifyIntegerConstantExpression(CondExpr, &condEval,
10573           diag::err_typecheck_choose_expr_requires_constant, false);
10574     if (CondICE.isInvalid())
10575       return ExprError();
10576     CondExpr = CondICE.get();
10577     CondIsTrue = condEval.getZExtValue();
10578 
10579     // If the condition is > zero, then the AST type is the same as the LSHExpr.
10580     Expr *ActiveExpr = CondIsTrue ? LHSExpr : RHSExpr;
10581 
10582     resType = ActiveExpr->getType();
10583     ValueDependent = ActiveExpr->isValueDependent();
10584     VK = ActiveExpr->getValueKind();
10585     OK = ActiveExpr->getObjectKind();
10586   }
10587 
10588   return new (Context)
10589       ChooseExpr(BuiltinLoc, CondExpr, LHSExpr, RHSExpr, resType, VK, OK, RPLoc,
10590                  CondIsTrue, resType->isDependentType(), ValueDependent);
10591 }
10592 
10593 //===----------------------------------------------------------------------===//
10594 // Clang Extensions.
10595 //===----------------------------------------------------------------------===//
10596 
10597 /// ActOnBlockStart - This callback is invoked when a block literal is started.
ActOnBlockStart(SourceLocation CaretLoc,Scope * CurScope)10598 void Sema::ActOnBlockStart(SourceLocation CaretLoc, Scope *CurScope) {
10599   BlockDecl *Block = BlockDecl::Create(Context, CurContext, CaretLoc);
10600 
10601   if (LangOpts.CPlusPlus) {
10602     Decl *ManglingContextDecl;
10603     if (MangleNumberingContext *MCtx =
10604             getCurrentMangleNumberContext(Block->getDeclContext(),
10605                                           ManglingContextDecl)) {
10606       unsigned ManglingNumber = MCtx->getManglingNumber(Block);
10607       Block->setBlockMangling(ManglingNumber, ManglingContextDecl);
10608     }
10609   }
10610 
10611   PushBlockScope(CurScope, Block);
10612   CurContext->addDecl(Block);
10613   if (CurScope)
10614     PushDeclContext(CurScope, Block);
10615   else
10616     CurContext = Block;
10617 
10618   getCurBlock()->HasImplicitReturnType = true;
10619 
10620   // Enter a new evaluation context to insulate the block from any
10621   // cleanups from the enclosing full-expression.
10622   PushExpressionEvaluationContext(PotentiallyEvaluated);
10623 }
10624 
ActOnBlockArguments(SourceLocation CaretLoc,Declarator & ParamInfo,Scope * CurScope)10625 void Sema::ActOnBlockArguments(SourceLocation CaretLoc, Declarator &ParamInfo,
10626                                Scope *CurScope) {
10627   assert(ParamInfo.getIdentifier() == nullptr &&
10628          "block-id should have no identifier!");
10629   assert(ParamInfo.getContext() == Declarator::BlockLiteralContext);
10630   BlockScopeInfo *CurBlock = getCurBlock();
10631 
10632   TypeSourceInfo *Sig = GetTypeForDeclarator(ParamInfo, CurScope);
10633   QualType T = Sig->getType();
10634 
10635   // FIXME: We should allow unexpanded parameter packs here, but that would,
10636   // in turn, make the block expression contain unexpanded parameter packs.
10637   if (DiagnoseUnexpandedParameterPack(CaretLoc, Sig, UPPC_Block)) {
10638     // Drop the parameters.
10639     FunctionProtoType::ExtProtoInfo EPI;
10640     EPI.HasTrailingReturn = false;
10641     EPI.TypeQuals |= DeclSpec::TQ_const;
10642     T = Context.getFunctionType(Context.DependentTy, None, EPI);
10643     Sig = Context.getTrivialTypeSourceInfo(T);
10644   }
10645 
10646   // GetTypeForDeclarator always produces a function type for a block
10647   // literal signature.  Furthermore, it is always a FunctionProtoType
10648   // unless the function was written with a typedef.
10649   assert(T->isFunctionType() &&
10650          "GetTypeForDeclarator made a non-function block signature");
10651 
10652   // Look for an explicit signature in that function type.
10653   FunctionProtoTypeLoc ExplicitSignature;
10654 
10655   TypeLoc tmp = Sig->getTypeLoc().IgnoreParens();
10656   if ((ExplicitSignature = tmp.getAs<FunctionProtoTypeLoc>())) {
10657 
10658     // Check whether that explicit signature was synthesized by
10659     // GetTypeForDeclarator.  If so, don't save that as part of the
10660     // written signature.
10661     if (ExplicitSignature.getLocalRangeBegin() ==
10662         ExplicitSignature.getLocalRangeEnd()) {
10663       // This would be much cheaper if we stored TypeLocs instead of
10664       // TypeSourceInfos.
10665       TypeLoc Result = ExplicitSignature.getReturnLoc();
10666       unsigned Size = Result.getFullDataSize();
10667       Sig = Context.CreateTypeSourceInfo(Result.getType(), Size);
10668       Sig->getTypeLoc().initializeFullCopy(Result, Size);
10669 
10670       ExplicitSignature = FunctionProtoTypeLoc();
10671     }
10672   }
10673 
10674   CurBlock->TheDecl->setSignatureAsWritten(Sig);
10675   CurBlock->FunctionType = T;
10676 
10677   const FunctionType *Fn = T->getAs<FunctionType>();
10678   QualType RetTy = Fn->getReturnType();
10679   bool isVariadic =
10680     (isa<FunctionProtoType>(Fn) && cast<FunctionProtoType>(Fn)->isVariadic());
10681 
10682   CurBlock->TheDecl->setIsVariadic(isVariadic);
10683 
10684   // Context.DependentTy is used as a placeholder for a missing block
10685   // return type.  TODO:  what should we do with declarators like:
10686   //   ^ * { ... }
10687   // If the answer is "apply template argument deduction"....
10688   if (RetTy != Context.DependentTy) {
10689     CurBlock->ReturnType = RetTy;
10690     CurBlock->TheDecl->setBlockMissingReturnType(false);
10691     CurBlock->HasImplicitReturnType = false;
10692   }
10693 
10694   // Push block parameters from the declarator if we had them.
10695   SmallVector<ParmVarDecl*, 8> Params;
10696   if (ExplicitSignature) {
10697     for (unsigned I = 0, E = ExplicitSignature.getNumParams(); I != E; ++I) {
10698       ParmVarDecl *Param = ExplicitSignature.getParam(I);
10699       if (Param->getIdentifier() == nullptr &&
10700           !Param->isImplicit() &&
10701           !Param->isInvalidDecl() &&
10702           !getLangOpts().CPlusPlus)
10703         Diag(Param->getLocation(), diag::err_parameter_name_omitted);
10704       Params.push_back(Param);
10705     }
10706 
10707   // Fake up parameter variables if we have a typedef, like
10708   //   ^ fntype { ... }
10709   } else if (const FunctionProtoType *Fn = T->getAs<FunctionProtoType>()) {
10710     for (const auto &I : Fn->param_types()) {
10711       ParmVarDecl *Param = BuildParmVarDeclForTypedef(
10712           CurBlock->TheDecl, ParamInfo.getLocStart(), I);
10713       Params.push_back(Param);
10714     }
10715   }
10716 
10717   // Set the parameters on the block decl.
10718   if (!Params.empty()) {
10719     CurBlock->TheDecl->setParams(Params);
10720     CheckParmsForFunctionDef(CurBlock->TheDecl->param_begin(),
10721                              CurBlock->TheDecl->param_end(),
10722                              /*CheckParameterNames=*/false);
10723   }
10724 
10725   // Finally we can process decl attributes.
10726   ProcessDeclAttributes(CurScope, CurBlock->TheDecl, ParamInfo);
10727 
10728   // Put the parameter variables in scope.
10729   for (auto AI : CurBlock->TheDecl->params()) {
10730     AI->setOwningFunction(CurBlock->TheDecl);
10731 
10732     // If this has an identifier, add it to the scope stack.
10733     if (AI->getIdentifier()) {
10734       CheckShadow(CurBlock->TheScope, AI);
10735 
10736       PushOnScopeChains(AI, CurBlock->TheScope);
10737     }
10738   }
10739 }
10740 
10741 /// ActOnBlockError - If there is an error parsing a block, this callback
10742 /// is invoked to pop the information about the block from the action impl.
ActOnBlockError(SourceLocation CaretLoc,Scope * CurScope)10743 void Sema::ActOnBlockError(SourceLocation CaretLoc, Scope *CurScope) {
10744   // Leave the expression-evaluation context.
10745   DiscardCleanupsInEvaluationContext();
10746   PopExpressionEvaluationContext();
10747 
10748   // Pop off CurBlock, handle nested blocks.
10749   PopDeclContext();
10750   PopFunctionScopeInfo();
10751 }
10752 
10753 /// ActOnBlockStmtExpr - This is called when the body of a block statement
10754 /// literal was successfully completed.  ^(int x){...}
ActOnBlockStmtExpr(SourceLocation CaretLoc,Stmt * Body,Scope * CurScope)10755 ExprResult Sema::ActOnBlockStmtExpr(SourceLocation CaretLoc,
10756                                     Stmt *Body, Scope *CurScope) {
10757   // If blocks are disabled, emit an error.
10758   if (!LangOpts.Blocks)
10759     Diag(CaretLoc, diag::err_blocks_disable);
10760 
10761   // Leave the expression-evaluation context.
10762   if (hasAnyUnrecoverableErrorsInThisFunction())
10763     DiscardCleanupsInEvaluationContext();
10764   assert(!ExprNeedsCleanups && "cleanups within block not correctly bound!");
10765   PopExpressionEvaluationContext();
10766 
10767   BlockScopeInfo *BSI = cast<BlockScopeInfo>(FunctionScopes.back());
10768 
10769   if (BSI->HasImplicitReturnType)
10770     deduceClosureReturnType(*BSI);
10771 
10772   PopDeclContext();
10773 
10774   QualType RetTy = Context.VoidTy;
10775   if (!BSI->ReturnType.isNull())
10776     RetTy = BSI->ReturnType;
10777 
10778   bool NoReturn = BSI->TheDecl->hasAttr<NoReturnAttr>();
10779   QualType BlockTy;
10780 
10781   // Set the captured variables on the block.
10782   // FIXME: Share capture structure between BlockDecl and CapturingScopeInfo!
10783   SmallVector<BlockDecl::Capture, 4> Captures;
10784   for (unsigned i = 0, e = BSI->Captures.size(); i != e; i++) {
10785     CapturingScopeInfo::Capture &Cap = BSI->Captures[i];
10786     if (Cap.isThisCapture())
10787       continue;
10788     BlockDecl::Capture NewCap(Cap.getVariable(), Cap.isBlockCapture(),
10789                               Cap.isNested(), Cap.getInitExpr());
10790     Captures.push_back(NewCap);
10791   }
10792   BSI->TheDecl->setCaptures(Context, Captures.begin(), Captures.end(),
10793                             BSI->CXXThisCaptureIndex != 0);
10794 
10795   // If the user wrote a function type in some form, try to use that.
10796   if (!BSI->FunctionType.isNull()) {
10797     const FunctionType *FTy = BSI->FunctionType->getAs<FunctionType>();
10798 
10799     FunctionType::ExtInfo Ext = FTy->getExtInfo();
10800     if (NoReturn && !Ext.getNoReturn()) Ext = Ext.withNoReturn(true);
10801 
10802     // Turn protoless block types into nullary block types.
10803     if (isa<FunctionNoProtoType>(FTy)) {
10804       FunctionProtoType::ExtProtoInfo EPI;
10805       EPI.ExtInfo = Ext;
10806       BlockTy = Context.getFunctionType(RetTy, None, EPI);
10807 
10808     // Otherwise, if we don't need to change anything about the function type,
10809     // preserve its sugar structure.
10810     } else if (FTy->getReturnType() == RetTy &&
10811                (!NoReturn || FTy->getNoReturnAttr())) {
10812       BlockTy = BSI->FunctionType;
10813 
10814     // Otherwise, make the minimal modifications to the function type.
10815     } else {
10816       const FunctionProtoType *FPT = cast<FunctionProtoType>(FTy);
10817       FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
10818       EPI.TypeQuals = 0; // FIXME: silently?
10819       EPI.ExtInfo = Ext;
10820       BlockTy = Context.getFunctionType(RetTy, FPT->getParamTypes(), EPI);
10821     }
10822 
10823   // If we don't have a function type, just build one from nothing.
10824   } else {
10825     FunctionProtoType::ExtProtoInfo EPI;
10826     EPI.ExtInfo = FunctionType::ExtInfo().withNoReturn(NoReturn);
10827     BlockTy = Context.getFunctionType(RetTy, None, EPI);
10828   }
10829 
10830   DiagnoseUnusedParameters(BSI->TheDecl->param_begin(),
10831                            BSI->TheDecl->param_end());
10832   BlockTy = Context.getBlockPointerType(BlockTy);
10833 
10834   // If needed, diagnose invalid gotos and switches in the block.
10835   if (getCurFunction()->NeedsScopeChecking() &&
10836       !PP.isCodeCompletionEnabled())
10837     DiagnoseInvalidJumps(cast<CompoundStmt>(Body));
10838 
10839   BSI->TheDecl->setBody(cast<CompoundStmt>(Body));
10840 
10841   // Try to apply the named return value optimization. We have to check again
10842   // if we can do this, though, because blocks keep return statements around
10843   // to deduce an implicit return type.
10844   if (getLangOpts().CPlusPlus && RetTy->isRecordType() &&
10845       !BSI->TheDecl->isDependentContext())
10846     computeNRVO(Body, BSI);
10847 
10848   BlockExpr *Result = new (Context) BlockExpr(BSI->TheDecl, BlockTy);
10849   AnalysisBasedWarnings::Policy WP = AnalysisWarnings.getDefaultPolicy();
10850   PopFunctionScopeInfo(&WP, Result->getBlockDecl(), Result);
10851 
10852   // If the block isn't obviously global, i.e. it captures anything at
10853   // all, then we need to do a few things in the surrounding context:
10854   if (Result->getBlockDecl()->hasCaptures()) {
10855     // First, this expression has a new cleanup object.
10856     ExprCleanupObjects.push_back(Result->getBlockDecl());
10857     ExprNeedsCleanups = true;
10858 
10859     // It also gets a branch-protected scope if any of the captured
10860     // variables needs destruction.
10861     for (const auto &CI : Result->getBlockDecl()->captures()) {
10862       const VarDecl *var = CI.getVariable();
10863       if (var->getType().isDestructedType() != QualType::DK_none) {
10864         getCurFunction()->setHasBranchProtectedScope();
10865         break;
10866       }
10867     }
10868   }
10869 
10870   return Result;
10871 }
10872 
ActOnVAArg(SourceLocation BuiltinLoc,Expr * E,ParsedType Ty,SourceLocation RPLoc)10873 ExprResult Sema::ActOnVAArg(SourceLocation BuiltinLoc,
10874                                         Expr *E, ParsedType Ty,
10875                                         SourceLocation RPLoc) {
10876   TypeSourceInfo *TInfo;
10877   GetTypeFromParser(Ty, &TInfo);
10878   return BuildVAArgExpr(BuiltinLoc, E, TInfo, RPLoc);
10879 }
10880 
BuildVAArgExpr(SourceLocation BuiltinLoc,Expr * E,TypeSourceInfo * TInfo,SourceLocation RPLoc)10881 ExprResult Sema::BuildVAArgExpr(SourceLocation BuiltinLoc,
10882                                 Expr *E, TypeSourceInfo *TInfo,
10883                                 SourceLocation RPLoc) {
10884   Expr *OrigExpr = E;
10885 
10886   // Get the va_list type
10887   QualType VaListType = Context.getBuiltinVaListType();
10888   if (VaListType->isArrayType()) {
10889     // Deal with implicit array decay; for example, on x86-64,
10890     // va_list is an array, but it's supposed to decay to
10891     // a pointer for va_arg.
10892     VaListType = Context.getArrayDecayedType(VaListType);
10893     // Make sure the input expression also decays appropriately.
10894     ExprResult Result = UsualUnaryConversions(E);
10895     if (Result.isInvalid())
10896       return ExprError();
10897     E = Result.get();
10898   } else if (VaListType->isRecordType() && getLangOpts().CPlusPlus) {
10899     // If va_list is a record type and we are compiling in C++ mode,
10900     // check the argument using reference binding.
10901     InitializedEntity Entity
10902       = InitializedEntity::InitializeParameter(Context,
10903           Context.getLValueReferenceType(VaListType), false);
10904     ExprResult Init = PerformCopyInitialization(Entity, SourceLocation(), E);
10905     if (Init.isInvalid())
10906       return ExprError();
10907     E = Init.getAs<Expr>();
10908   } else {
10909     // Otherwise, the va_list argument must be an l-value because
10910     // it is modified by va_arg.
10911     if (!E->isTypeDependent() &&
10912         CheckForModifiableLvalue(E, BuiltinLoc, *this))
10913       return ExprError();
10914   }
10915 
10916   if (!E->isTypeDependent() &&
10917       !Context.hasSameType(VaListType, E->getType())) {
10918     return ExprError(Diag(E->getLocStart(),
10919                          diag::err_first_argument_to_va_arg_not_of_type_va_list)
10920       << OrigExpr->getType() << E->getSourceRange());
10921   }
10922 
10923   if (!TInfo->getType()->isDependentType()) {
10924     if (RequireCompleteType(TInfo->getTypeLoc().getBeginLoc(), TInfo->getType(),
10925                             diag::err_second_parameter_to_va_arg_incomplete,
10926                             TInfo->getTypeLoc()))
10927       return ExprError();
10928 
10929     if (RequireNonAbstractType(TInfo->getTypeLoc().getBeginLoc(),
10930                                TInfo->getType(),
10931                                diag::err_second_parameter_to_va_arg_abstract,
10932                                TInfo->getTypeLoc()))
10933       return ExprError();
10934 
10935     if (!TInfo->getType().isPODType(Context)) {
10936       Diag(TInfo->getTypeLoc().getBeginLoc(),
10937            TInfo->getType()->isObjCLifetimeType()
10938              ? diag::warn_second_parameter_to_va_arg_ownership_qualified
10939              : diag::warn_second_parameter_to_va_arg_not_pod)
10940         << TInfo->getType()
10941         << TInfo->getTypeLoc().getSourceRange();
10942     }
10943 
10944     // Check for va_arg where arguments of the given type will be promoted
10945     // (i.e. this va_arg is guaranteed to have undefined behavior).
10946     QualType PromoteType;
10947     if (TInfo->getType()->isPromotableIntegerType()) {
10948       PromoteType = Context.getPromotedIntegerType(TInfo->getType());
10949       if (Context.typesAreCompatible(PromoteType, TInfo->getType()))
10950         PromoteType = QualType();
10951     }
10952     if (TInfo->getType()->isSpecificBuiltinType(BuiltinType::Float))
10953       PromoteType = Context.DoubleTy;
10954     if (!PromoteType.isNull())
10955       DiagRuntimeBehavior(TInfo->getTypeLoc().getBeginLoc(), E,
10956                   PDiag(diag::warn_second_parameter_to_va_arg_never_compatible)
10957                           << TInfo->getType()
10958                           << PromoteType
10959                           << TInfo->getTypeLoc().getSourceRange());
10960   }
10961 
10962   QualType T = TInfo->getType().getNonLValueExprType(Context);
10963   return new (Context) VAArgExpr(BuiltinLoc, E, TInfo, RPLoc, T);
10964 }
10965 
ActOnGNUNullExpr(SourceLocation TokenLoc)10966 ExprResult Sema::ActOnGNUNullExpr(SourceLocation TokenLoc) {
10967   // The type of __null will be int or long, depending on the size of
10968   // pointers on the target.
10969   QualType Ty;
10970   unsigned pw = Context.getTargetInfo().getPointerWidth(0);
10971   if (pw == Context.getTargetInfo().getIntWidth())
10972     Ty = Context.IntTy;
10973   else if (pw == Context.getTargetInfo().getLongWidth())
10974     Ty = Context.LongTy;
10975   else if (pw == Context.getTargetInfo().getLongLongWidth())
10976     Ty = Context.LongLongTy;
10977   else {
10978     llvm_unreachable("I don't know size of pointer!");
10979   }
10980 
10981   return new (Context) GNUNullExpr(Ty, TokenLoc);
10982 }
10983 
10984 bool
ConversionToObjCStringLiteralCheck(QualType DstType,Expr * & Exp)10985 Sema::ConversionToObjCStringLiteralCheck(QualType DstType, Expr *&Exp) {
10986   if (!getLangOpts().ObjC1)
10987     return false;
10988 
10989   const ObjCObjectPointerType *PT = DstType->getAs<ObjCObjectPointerType>();
10990   if (!PT)
10991     return false;
10992 
10993   if (!PT->isObjCIdType()) {
10994     // Check if the destination is the 'NSString' interface.
10995     const ObjCInterfaceDecl *ID = PT->getInterfaceDecl();
10996     if (!ID || !ID->getIdentifier()->isStr("NSString"))
10997       return false;
10998   }
10999 
11000   // Ignore any parens, implicit casts (should only be
11001   // array-to-pointer decays), and not-so-opaque values.  The last is
11002   // important for making this trigger for property assignments.
11003   Expr *SrcExpr = Exp->IgnoreParenImpCasts();
11004   if (OpaqueValueExpr *OV = dyn_cast<OpaqueValueExpr>(SrcExpr))
11005     if (OV->getSourceExpr())
11006       SrcExpr = OV->getSourceExpr()->IgnoreParenImpCasts();
11007 
11008   StringLiteral *SL = dyn_cast<StringLiteral>(SrcExpr);
11009   if (!SL || !SL->isAscii())
11010     return false;
11011   Diag(SL->getLocStart(), diag::err_missing_atsign_prefix)
11012     << FixItHint::CreateInsertion(SL->getLocStart(), "@");
11013   Exp = BuildObjCStringLiteral(SL->getLocStart(), SL).get();
11014   return true;
11015 }
11016 
DiagnoseAssignmentResult(AssignConvertType ConvTy,SourceLocation Loc,QualType DstType,QualType SrcType,Expr * SrcExpr,AssignmentAction Action,bool * Complained)11017 bool Sema::DiagnoseAssignmentResult(AssignConvertType ConvTy,
11018                                     SourceLocation Loc,
11019                                     QualType DstType, QualType SrcType,
11020                                     Expr *SrcExpr, AssignmentAction Action,
11021                                     bool *Complained) {
11022   if (Complained)
11023     *Complained = false;
11024 
11025   // Decode the result (notice that AST's are still created for extensions).
11026   bool CheckInferredResultType = false;
11027   bool isInvalid = false;
11028   unsigned DiagKind = 0;
11029   FixItHint Hint;
11030   ConversionFixItGenerator ConvHints;
11031   bool MayHaveConvFixit = false;
11032   bool MayHaveFunctionDiff = false;
11033   const ObjCInterfaceDecl *IFace = nullptr;
11034   const ObjCProtocolDecl *PDecl = nullptr;
11035 
11036   switch (ConvTy) {
11037   case Compatible:
11038       DiagnoseAssignmentEnum(DstType, SrcType, SrcExpr);
11039       return false;
11040 
11041   case PointerToInt:
11042     DiagKind = diag::ext_typecheck_convert_pointer_int;
11043     ConvHints.tryToFixConversion(SrcExpr, SrcType, DstType, *this);
11044     MayHaveConvFixit = true;
11045     break;
11046   case IntToPointer:
11047     DiagKind = diag::ext_typecheck_convert_int_pointer;
11048     ConvHints.tryToFixConversion(SrcExpr, SrcType, DstType, *this);
11049     MayHaveConvFixit = true;
11050     break;
11051   case IncompatiblePointer:
11052       DiagKind =
11053         (Action == AA_Passing_CFAudited ?
11054           diag::err_arc_typecheck_convert_incompatible_pointer :
11055           diag::ext_typecheck_convert_incompatible_pointer);
11056     CheckInferredResultType = DstType->isObjCObjectPointerType() &&
11057       SrcType->isObjCObjectPointerType();
11058     if (Hint.isNull() && !CheckInferredResultType) {
11059       ConvHints.tryToFixConversion(SrcExpr, SrcType, DstType, *this);
11060     }
11061     else if (CheckInferredResultType) {
11062       SrcType = SrcType.getUnqualifiedType();
11063       DstType = DstType.getUnqualifiedType();
11064     }
11065     MayHaveConvFixit = true;
11066     break;
11067   case IncompatiblePointerSign:
11068     DiagKind = diag::ext_typecheck_convert_incompatible_pointer_sign;
11069     break;
11070   case FunctionVoidPointer:
11071     DiagKind = diag::ext_typecheck_convert_pointer_void_func;
11072     break;
11073   case IncompatiblePointerDiscardsQualifiers: {
11074     // Perform array-to-pointer decay if necessary.
11075     if (SrcType->isArrayType()) SrcType = Context.getArrayDecayedType(SrcType);
11076 
11077     Qualifiers lhq = SrcType->getPointeeType().getQualifiers();
11078     Qualifiers rhq = DstType->getPointeeType().getQualifiers();
11079     if (lhq.getAddressSpace() != rhq.getAddressSpace()) {
11080       DiagKind = diag::err_typecheck_incompatible_address_space;
11081       break;
11082 
11083 
11084     } else if (lhq.getObjCLifetime() != rhq.getObjCLifetime()) {
11085       DiagKind = diag::err_typecheck_incompatible_ownership;
11086       break;
11087     }
11088 
11089     llvm_unreachable("unknown error case for discarding qualifiers!");
11090     // fallthrough
11091   }
11092   case CompatiblePointerDiscardsQualifiers:
11093     // If the qualifiers lost were because we were applying the
11094     // (deprecated) C++ conversion from a string literal to a char*
11095     // (or wchar_t*), then there was no error (C++ 4.2p2).  FIXME:
11096     // Ideally, this check would be performed in
11097     // checkPointerTypesForAssignment. However, that would require a
11098     // bit of refactoring (so that the second argument is an
11099     // expression, rather than a type), which should be done as part
11100     // of a larger effort to fix checkPointerTypesForAssignment for
11101     // C++ semantics.
11102     if (getLangOpts().CPlusPlus &&
11103         IsStringLiteralToNonConstPointerConversion(SrcExpr, DstType))
11104       return false;
11105     DiagKind = diag::ext_typecheck_convert_discards_qualifiers;
11106     break;
11107   case IncompatibleNestedPointerQualifiers:
11108     DiagKind = diag::ext_nested_pointer_qualifier_mismatch;
11109     break;
11110   case IntToBlockPointer:
11111     DiagKind = diag::err_int_to_block_pointer;
11112     break;
11113   case IncompatibleBlockPointer:
11114     DiagKind = diag::err_typecheck_convert_incompatible_block_pointer;
11115     break;
11116   case IncompatibleObjCQualifiedId: {
11117     if (SrcType->isObjCQualifiedIdType()) {
11118       const ObjCObjectPointerType *srcOPT =
11119                 SrcType->getAs<ObjCObjectPointerType>();
11120       for (auto *srcProto : srcOPT->quals()) {
11121         PDecl = srcProto;
11122         break;
11123       }
11124       if (const ObjCInterfaceType *IFaceT =
11125             DstType->getAs<ObjCObjectPointerType>()->getInterfaceType())
11126         IFace = IFaceT->getDecl();
11127     }
11128     else if (DstType->isObjCQualifiedIdType()) {
11129       const ObjCObjectPointerType *dstOPT =
11130         DstType->getAs<ObjCObjectPointerType>();
11131       for (auto *dstProto : dstOPT->quals()) {
11132         PDecl = dstProto;
11133         break;
11134       }
11135       if (const ObjCInterfaceType *IFaceT =
11136             SrcType->getAs<ObjCObjectPointerType>()->getInterfaceType())
11137         IFace = IFaceT->getDecl();
11138     }
11139     DiagKind = diag::warn_incompatible_qualified_id;
11140     break;
11141   }
11142   case IncompatibleVectors:
11143     DiagKind = diag::warn_incompatible_vectors;
11144     break;
11145   case IncompatibleObjCWeakRef:
11146     DiagKind = diag::err_arc_weak_unavailable_assign;
11147     break;
11148   case Incompatible:
11149     DiagKind = diag::err_typecheck_convert_incompatible;
11150     ConvHints.tryToFixConversion(SrcExpr, SrcType, DstType, *this);
11151     MayHaveConvFixit = true;
11152     isInvalid = true;
11153     MayHaveFunctionDiff = true;
11154     break;
11155   }
11156 
11157   QualType FirstType, SecondType;
11158   switch (Action) {
11159   case AA_Assigning:
11160   case AA_Initializing:
11161     // The destination type comes first.
11162     FirstType = DstType;
11163     SecondType = SrcType;
11164     break;
11165 
11166   case AA_Returning:
11167   case AA_Passing:
11168   case AA_Passing_CFAudited:
11169   case AA_Converting:
11170   case AA_Sending:
11171   case AA_Casting:
11172     // The source type comes first.
11173     FirstType = SrcType;
11174     SecondType = DstType;
11175     break;
11176   }
11177 
11178   PartialDiagnostic FDiag = PDiag(DiagKind);
11179   if (Action == AA_Passing_CFAudited)
11180     FDiag << FirstType << SecondType << AA_Passing << SrcExpr->getSourceRange();
11181   else
11182     FDiag << FirstType << SecondType << Action << SrcExpr->getSourceRange();
11183 
11184   // If we can fix the conversion, suggest the FixIts.
11185   assert(ConvHints.isNull() || Hint.isNull());
11186   if (!ConvHints.isNull()) {
11187     for (std::vector<FixItHint>::iterator HI = ConvHints.Hints.begin(),
11188          HE = ConvHints.Hints.end(); HI != HE; ++HI)
11189       FDiag << *HI;
11190   } else {
11191     FDiag << Hint;
11192   }
11193   if (MayHaveConvFixit) { FDiag << (unsigned) (ConvHints.Kind); }
11194 
11195   if (MayHaveFunctionDiff)
11196     HandleFunctionTypeMismatch(FDiag, SecondType, FirstType);
11197 
11198   Diag(Loc, FDiag);
11199   if (DiagKind == diag::warn_incompatible_qualified_id &&
11200       PDecl && IFace && !IFace->hasDefinition())
11201       Diag(IFace->getLocation(), diag::not_incomplete_class_and_qualified_id)
11202         << IFace->getName() << PDecl->getName();
11203 
11204   if (SecondType == Context.OverloadTy)
11205     NoteAllOverloadCandidates(OverloadExpr::find(SrcExpr).Expression,
11206                               FirstType);
11207 
11208   if (CheckInferredResultType)
11209     EmitRelatedResultTypeNote(SrcExpr);
11210 
11211   if (Action == AA_Returning && ConvTy == IncompatiblePointer)
11212     EmitRelatedResultTypeNoteForReturn(DstType);
11213 
11214   if (Complained)
11215     *Complained = true;
11216   return isInvalid;
11217 }
11218 
VerifyIntegerConstantExpression(Expr * E,llvm::APSInt * Result)11219 ExprResult Sema::VerifyIntegerConstantExpression(Expr *E,
11220                                                  llvm::APSInt *Result) {
11221   class SimpleICEDiagnoser : public VerifyICEDiagnoser {
11222   public:
11223     void diagnoseNotICE(Sema &S, SourceLocation Loc, SourceRange SR) override {
11224       S.Diag(Loc, diag::err_expr_not_ice) << S.LangOpts.CPlusPlus << SR;
11225     }
11226   } Diagnoser;
11227 
11228   return VerifyIntegerConstantExpression(E, Result, Diagnoser);
11229 }
11230 
VerifyIntegerConstantExpression(Expr * E,llvm::APSInt * Result,unsigned DiagID,bool AllowFold)11231 ExprResult Sema::VerifyIntegerConstantExpression(Expr *E,
11232                                                  llvm::APSInt *Result,
11233                                                  unsigned DiagID,
11234                                                  bool AllowFold) {
11235   class IDDiagnoser : public VerifyICEDiagnoser {
11236     unsigned DiagID;
11237 
11238   public:
11239     IDDiagnoser(unsigned DiagID)
11240       : VerifyICEDiagnoser(DiagID == 0), DiagID(DiagID) { }
11241 
11242     void diagnoseNotICE(Sema &S, SourceLocation Loc, SourceRange SR) override {
11243       S.Diag(Loc, DiagID) << SR;
11244     }
11245   } Diagnoser(DiagID);
11246 
11247   return VerifyIntegerConstantExpression(E, Result, Diagnoser, AllowFold);
11248 }
11249 
diagnoseFold(Sema & S,SourceLocation Loc,SourceRange SR)11250 void Sema::VerifyICEDiagnoser::diagnoseFold(Sema &S, SourceLocation Loc,
11251                                             SourceRange SR) {
11252   S.Diag(Loc, diag::ext_expr_not_ice) << SR << S.LangOpts.CPlusPlus;
11253 }
11254 
11255 ExprResult
VerifyIntegerConstantExpression(Expr * E,llvm::APSInt * Result,VerifyICEDiagnoser & Diagnoser,bool AllowFold)11256 Sema::VerifyIntegerConstantExpression(Expr *E, llvm::APSInt *Result,
11257                                       VerifyICEDiagnoser &Diagnoser,
11258                                       bool AllowFold) {
11259   SourceLocation DiagLoc = E->getLocStart();
11260 
11261   if (getLangOpts().CPlusPlus11) {
11262     // C++11 [expr.const]p5:
11263     //   If an expression of literal class type is used in a context where an
11264     //   integral constant expression is required, then that class type shall
11265     //   have a single non-explicit conversion function to an integral or
11266     //   unscoped enumeration type
11267     ExprResult Converted;
11268     class CXX11ConvertDiagnoser : public ICEConvertDiagnoser {
11269     public:
11270       CXX11ConvertDiagnoser(bool Silent)
11271           : ICEConvertDiagnoser(/*AllowScopedEnumerations*/false,
11272                                 Silent, true) {}
11273 
11274       SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
11275                                            QualType T) override {
11276         return S.Diag(Loc, diag::err_ice_not_integral) << T;
11277       }
11278 
11279       SemaDiagnosticBuilder diagnoseIncomplete(
11280           Sema &S, SourceLocation Loc, QualType T) override {
11281         return S.Diag(Loc, diag::err_ice_incomplete_type) << T;
11282       }
11283 
11284       SemaDiagnosticBuilder diagnoseExplicitConv(
11285           Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
11286         return S.Diag(Loc, diag::err_ice_explicit_conversion) << T << ConvTy;
11287       }
11288 
11289       SemaDiagnosticBuilder noteExplicitConv(
11290           Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
11291         return S.Diag(Conv->getLocation(), diag::note_ice_conversion_here)
11292                  << ConvTy->isEnumeralType() << ConvTy;
11293       }
11294 
11295       SemaDiagnosticBuilder diagnoseAmbiguous(
11296           Sema &S, SourceLocation Loc, QualType T) override {
11297         return S.Diag(Loc, diag::err_ice_ambiguous_conversion) << T;
11298       }
11299 
11300       SemaDiagnosticBuilder noteAmbiguous(
11301           Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
11302         return S.Diag(Conv->getLocation(), diag::note_ice_conversion_here)
11303                  << ConvTy->isEnumeralType() << ConvTy;
11304       }
11305 
11306       SemaDiagnosticBuilder diagnoseConversion(
11307           Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
11308         llvm_unreachable("conversion functions are permitted");
11309       }
11310     } ConvertDiagnoser(Diagnoser.Suppress);
11311 
11312     Converted = PerformContextualImplicitConversion(DiagLoc, E,
11313                                                     ConvertDiagnoser);
11314     if (Converted.isInvalid())
11315       return Converted;
11316     E = Converted.get();
11317     if (!E->getType()->isIntegralOrUnscopedEnumerationType())
11318       return ExprError();
11319   } else if (!E->getType()->isIntegralOrUnscopedEnumerationType()) {
11320     // An ICE must be of integral or unscoped enumeration type.
11321     if (!Diagnoser.Suppress)
11322       Diagnoser.diagnoseNotICE(*this, DiagLoc, E->getSourceRange());
11323     return ExprError();
11324   }
11325 
11326   // Circumvent ICE checking in C++11 to avoid evaluating the expression twice
11327   // in the non-ICE case.
11328   if (!getLangOpts().CPlusPlus11 && E->isIntegerConstantExpr(Context)) {
11329     if (Result)
11330       *Result = E->EvaluateKnownConstInt(Context);
11331     return E;
11332   }
11333 
11334   Expr::EvalResult EvalResult;
11335   SmallVector<PartialDiagnosticAt, 8> Notes;
11336   EvalResult.Diag = &Notes;
11337 
11338   // Try to evaluate the expression, and produce diagnostics explaining why it's
11339   // not a constant expression as a side-effect.
11340   bool Folded = E->EvaluateAsRValue(EvalResult, Context) &&
11341                 EvalResult.Val.isInt() && !EvalResult.HasSideEffects;
11342 
11343   // In C++11, we can rely on diagnostics being produced for any expression
11344   // which is not a constant expression. If no diagnostics were produced, then
11345   // this is a constant expression.
11346   if (Folded && getLangOpts().CPlusPlus11 && Notes.empty()) {
11347     if (Result)
11348       *Result = EvalResult.Val.getInt();
11349     return E;
11350   }
11351 
11352   // If our only note is the usual "invalid subexpression" note, just point
11353   // the caret at its location rather than producing an essentially
11354   // redundant note.
11355   if (Notes.size() == 1 && Notes[0].second.getDiagID() ==
11356         diag::note_invalid_subexpr_in_const_expr) {
11357     DiagLoc = Notes[0].first;
11358     Notes.clear();
11359   }
11360 
11361   if (!Folded || !AllowFold) {
11362     if (!Diagnoser.Suppress) {
11363       Diagnoser.diagnoseNotICE(*this, DiagLoc, E->getSourceRange());
11364       for (unsigned I = 0, N = Notes.size(); I != N; ++I)
11365         Diag(Notes[I].first, Notes[I].second);
11366     }
11367 
11368     return ExprError();
11369   }
11370 
11371   Diagnoser.diagnoseFold(*this, DiagLoc, E->getSourceRange());
11372   for (unsigned I = 0, N = Notes.size(); I != N; ++I)
11373     Diag(Notes[I].first, Notes[I].second);
11374 
11375   if (Result)
11376     *Result = EvalResult.Val.getInt();
11377   return E;
11378 }
11379 
11380 namespace {
11381   // Handle the case where we conclude a expression which we speculatively
11382   // considered to be unevaluated is actually evaluated.
11383   class TransformToPE : public TreeTransform<TransformToPE> {
11384     typedef TreeTransform<TransformToPE> BaseTransform;
11385 
11386   public:
TransformToPE(Sema & SemaRef)11387     TransformToPE(Sema &SemaRef) : BaseTransform(SemaRef) { }
11388 
11389     // Make sure we redo semantic analysis
AlwaysRebuild()11390     bool AlwaysRebuild() { return true; }
11391 
11392     // Make sure we handle LabelStmts correctly.
11393     // FIXME: This does the right thing, but maybe we need a more general
11394     // fix to TreeTransform?
TransformLabelStmt(LabelStmt * S)11395     StmtResult TransformLabelStmt(LabelStmt *S) {
11396       S->getDecl()->setStmt(nullptr);
11397       return BaseTransform::TransformLabelStmt(S);
11398     }
11399 
11400     // We need to special-case DeclRefExprs referring to FieldDecls which
11401     // are not part of a member pointer formation; normal TreeTransforming
11402     // doesn't catch this case because of the way we represent them in the AST.
11403     // FIXME: This is a bit ugly; is it really the best way to handle this
11404     // case?
11405     //
11406     // Error on DeclRefExprs referring to FieldDecls.
TransformDeclRefExpr(DeclRefExpr * E)11407     ExprResult TransformDeclRefExpr(DeclRefExpr *E) {
11408       if (isa<FieldDecl>(E->getDecl()) &&
11409           !SemaRef.isUnevaluatedContext())
11410         return SemaRef.Diag(E->getLocation(),
11411                             diag::err_invalid_non_static_member_use)
11412             << E->getDecl() << E->getSourceRange();
11413 
11414       return BaseTransform::TransformDeclRefExpr(E);
11415     }
11416 
11417     // Exception: filter out member pointer formation
TransformUnaryOperator(UnaryOperator * E)11418     ExprResult TransformUnaryOperator(UnaryOperator *E) {
11419       if (E->getOpcode() == UO_AddrOf && E->getType()->isMemberPointerType())
11420         return E;
11421 
11422       return BaseTransform::TransformUnaryOperator(E);
11423     }
11424 
TransformLambdaExpr(LambdaExpr * E)11425     ExprResult TransformLambdaExpr(LambdaExpr *E) {
11426       // Lambdas never need to be transformed.
11427       return E;
11428     }
11429   };
11430 }
11431 
TransformToPotentiallyEvaluated(Expr * E)11432 ExprResult Sema::TransformToPotentiallyEvaluated(Expr *E) {
11433   assert(isUnevaluatedContext() &&
11434          "Should only transform unevaluated expressions");
11435   ExprEvalContexts.back().Context =
11436       ExprEvalContexts[ExprEvalContexts.size()-2].Context;
11437   if (isUnevaluatedContext())
11438     return E;
11439   return TransformToPE(*this).TransformExpr(E);
11440 }
11441 
11442 void
PushExpressionEvaluationContext(ExpressionEvaluationContext NewContext,Decl * LambdaContextDecl,bool IsDecltype)11443 Sema::PushExpressionEvaluationContext(ExpressionEvaluationContext NewContext,
11444                                       Decl *LambdaContextDecl,
11445                                       bool IsDecltype) {
11446   ExprEvalContexts.push_back(
11447              ExpressionEvaluationContextRecord(NewContext,
11448                                                ExprCleanupObjects.size(),
11449                                                ExprNeedsCleanups,
11450                                                LambdaContextDecl,
11451                                                IsDecltype));
11452   ExprNeedsCleanups = false;
11453   if (!MaybeODRUseExprs.empty())
11454     std::swap(MaybeODRUseExprs, ExprEvalContexts.back().SavedMaybeODRUseExprs);
11455 }
11456 
11457 void
PushExpressionEvaluationContext(ExpressionEvaluationContext NewContext,ReuseLambdaContextDecl_t,bool IsDecltype)11458 Sema::PushExpressionEvaluationContext(ExpressionEvaluationContext NewContext,
11459                                       ReuseLambdaContextDecl_t,
11460                                       bool IsDecltype) {
11461   Decl *ClosureContextDecl = ExprEvalContexts.back().ManglingContextDecl;
11462   PushExpressionEvaluationContext(NewContext, ClosureContextDecl, IsDecltype);
11463 }
11464 
PopExpressionEvaluationContext()11465 void Sema::PopExpressionEvaluationContext() {
11466   ExpressionEvaluationContextRecord& Rec = ExprEvalContexts.back();
11467   unsigned NumTypos = Rec.NumTypos;
11468 
11469   if (!Rec.Lambdas.empty()) {
11470     if (Rec.isUnevaluated() || Rec.Context == ConstantEvaluated) {
11471       unsigned D;
11472       if (Rec.isUnevaluated()) {
11473         // C++11 [expr.prim.lambda]p2:
11474         //   A lambda-expression shall not appear in an unevaluated operand
11475         //   (Clause 5).
11476         D = diag::err_lambda_unevaluated_operand;
11477       } else {
11478         // C++1y [expr.const]p2:
11479         //   A conditional-expression e is a core constant expression unless the
11480         //   evaluation of e, following the rules of the abstract machine, would
11481         //   evaluate [...] a lambda-expression.
11482         D = diag::err_lambda_in_constant_expression;
11483       }
11484       for (const auto *L : Rec.Lambdas)
11485         Diag(L->getLocStart(), D);
11486     } else {
11487       // Mark the capture expressions odr-used. This was deferred
11488       // during lambda expression creation.
11489       for (auto *Lambda : Rec.Lambdas) {
11490         for (auto *C : Lambda->capture_inits())
11491           MarkDeclarationsReferencedInExpr(C);
11492       }
11493     }
11494   }
11495 
11496   // When are coming out of an unevaluated context, clear out any
11497   // temporaries that we may have created as part of the evaluation of
11498   // the expression in that context: they aren't relevant because they
11499   // will never be constructed.
11500   if (Rec.isUnevaluated() || Rec.Context == ConstantEvaluated) {
11501     ExprCleanupObjects.erase(ExprCleanupObjects.begin() + Rec.NumCleanupObjects,
11502                              ExprCleanupObjects.end());
11503     ExprNeedsCleanups = Rec.ParentNeedsCleanups;
11504     CleanupVarDeclMarking();
11505     std::swap(MaybeODRUseExprs, Rec.SavedMaybeODRUseExprs);
11506   // Otherwise, merge the contexts together.
11507   } else {
11508     ExprNeedsCleanups |= Rec.ParentNeedsCleanups;
11509     MaybeODRUseExprs.insert(Rec.SavedMaybeODRUseExprs.begin(),
11510                             Rec.SavedMaybeODRUseExprs.end());
11511   }
11512 
11513   // Pop the current expression evaluation context off the stack.
11514   ExprEvalContexts.pop_back();
11515 
11516   if (!ExprEvalContexts.empty())
11517     ExprEvalContexts.back().NumTypos += NumTypos;
11518   else
11519     assert(NumTypos == 0 && "There are outstanding typos after popping the "
11520                             "last ExpressionEvaluationContextRecord");
11521 }
11522 
DiscardCleanupsInEvaluationContext()11523 void Sema::DiscardCleanupsInEvaluationContext() {
11524   ExprCleanupObjects.erase(
11525          ExprCleanupObjects.begin() + ExprEvalContexts.back().NumCleanupObjects,
11526          ExprCleanupObjects.end());
11527   ExprNeedsCleanups = false;
11528   MaybeODRUseExprs.clear();
11529 }
11530 
HandleExprEvaluationContextForTypeof(Expr * E)11531 ExprResult Sema::HandleExprEvaluationContextForTypeof(Expr *E) {
11532   if (!E->getType()->isVariablyModifiedType())
11533     return E;
11534   return TransformToPotentiallyEvaluated(E);
11535 }
11536 
IsPotentiallyEvaluatedContext(Sema & SemaRef)11537 static bool IsPotentiallyEvaluatedContext(Sema &SemaRef) {
11538   // Do not mark anything as "used" within a dependent context; wait for
11539   // an instantiation.
11540   if (SemaRef.CurContext->isDependentContext())
11541     return false;
11542 
11543   switch (SemaRef.ExprEvalContexts.back().Context) {
11544     case Sema::Unevaluated:
11545     case Sema::UnevaluatedAbstract:
11546       // We are in an expression that is not potentially evaluated; do nothing.
11547       // (Depending on how you read the standard, we actually do need to do
11548       // something here for null pointer constants, but the standard's
11549       // definition of a null pointer constant is completely crazy.)
11550       return false;
11551 
11552     case Sema::ConstantEvaluated:
11553     case Sema::PotentiallyEvaluated:
11554       // We are in a potentially evaluated expression (or a constant-expression
11555       // in C++03); we need to do implicit template instantiation, implicitly
11556       // define class members, and mark most declarations as used.
11557       return true;
11558 
11559     case Sema::PotentiallyEvaluatedIfUsed:
11560       // Referenced declarations will only be used if the construct in the
11561       // containing expression is used.
11562       return false;
11563   }
11564   llvm_unreachable("Invalid context");
11565 }
11566 
11567 /// \brief Mark a function referenced, and check whether it is odr-used
11568 /// (C++ [basic.def.odr]p2, C99 6.9p3)
MarkFunctionReferenced(SourceLocation Loc,FunctionDecl * Func,bool OdrUse)11569 void Sema::MarkFunctionReferenced(SourceLocation Loc, FunctionDecl *Func,
11570                                   bool OdrUse) {
11571   assert(Func && "No function?");
11572 
11573   Func->setReferenced();
11574 
11575   // C++11 [basic.def.odr]p3:
11576   //   A function whose name appears as a potentially-evaluated expression is
11577   //   odr-used if it is the unique lookup result or the selected member of a
11578   //   set of overloaded functions [...].
11579   //
11580   // We (incorrectly) mark overload resolution as an unevaluated context, so we
11581   // can just check that here. Skip the rest of this function if we've already
11582   // marked the function as used.
11583   if (Func->isUsed(false) || !IsPotentiallyEvaluatedContext(*this)) {
11584     // C++11 [temp.inst]p3:
11585     //   Unless a function template specialization has been explicitly
11586     //   instantiated or explicitly specialized, the function template
11587     //   specialization is implicitly instantiated when the specialization is
11588     //   referenced in a context that requires a function definition to exist.
11589     //
11590     // We consider constexpr function templates to be referenced in a context
11591     // that requires a definition to exist whenever they are referenced.
11592     //
11593     // FIXME: This instantiates constexpr functions too frequently. If this is
11594     // really an unevaluated context (and we're not just in the definition of a
11595     // function template or overload resolution or other cases which we
11596     // incorrectly consider to be unevaluated contexts), and we're not in a
11597     // subexpression which we actually need to evaluate (for instance, a
11598     // template argument, array bound or an expression in a braced-init-list),
11599     // we are not permitted to instantiate this constexpr function definition.
11600     //
11601     // FIXME: This also implicitly defines special members too frequently. They
11602     // are only supposed to be implicitly defined if they are odr-used, but they
11603     // are not odr-used from constant expressions in unevaluated contexts.
11604     // However, they cannot be referenced if they are deleted, and they are
11605     // deleted whenever the implicit definition of the special member would
11606     // fail.
11607     if (!Func->isConstexpr() || Func->getBody())
11608       return;
11609     CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Func);
11610     if (!Func->isImplicitlyInstantiable() && (!MD || MD->isUserProvided()))
11611       return;
11612   }
11613 
11614   // Note that this declaration has been used.
11615   if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Func)) {
11616     Constructor = cast<CXXConstructorDecl>(Constructor->getFirstDecl());
11617     if (Constructor->isDefaulted() && !Constructor->isDeleted()) {
11618       if (Constructor->isDefaultConstructor()) {
11619         if (Constructor->isTrivial() && !Constructor->hasAttr<DLLExportAttr>())
11620           return;
11621         DefineImplicitDefaultConstructor(Loc, Constructor);
11622       } else if (Constructor->isCopyConstructor()) {
11623         DefineImplicitCopyConstructor(Loc, Constructor);
11624       } else if (Constructor->isMoveConstructor()) {
11625         DefineImplicitMoveConstructor(Loc, Constructor);
11626       }
11627     } else if (Constructor->getInheritedConstructor()) {
11628       DefineInheritingConstructor(Loc, Constructor);
11629     }
11630   } else if (CXXDestructorDecl *Destructor =
11631                  dyn_cast<CXXDestructorDecl>(Func)) {
11632     Destructor = cast<CXXDestructorDecl>(Destructor->getFirstDecl());
11633     if (Destructor->isDefaulted() && !Destructor->isDeleted()) {
11634       if (Destructor->isTrivial() && !Destructor->hasAttr<DLLExportAttr>())
11635         return;
11636       DefineImplicitDestructor(Loc, Destructor);
11637     }
11638     if (Destructor->isVirtual())
11639       MarkVTableUsed(Loc, Destructor->getParent());
11640   } else if (CXXMethodDecl *MethodDecl = dyn_cast<CXXMethodDecl>(Func)) {
11641     if (MethodDecl->isOverloadedOperator() &&
11642         MethodDecl->getOverloadedOperator() == OO_Equal) {
11643       MethodDecl = cast<CXXMethodDecl>(MethodDecl->getFirstDecl());
11644       if (MethodDecl->isDefaulted() && !MethodDecl->isDeleted()) {
11645         if (MethodDecl->isCopyAssignmentOperator())
11646           DefineImplicitCopyAssignment(Loc, MethodDecl);
11647         else
11648           DefineImplicitMoveAssignment(Loc, MethodDecl);
11649       }
11650     } else if (isa<CXXConversionDecl>(MethodDecl) &&
11651                MethodDecl->getParent()->isLambda()) {
11652       CXXConversionDecl *Conversion =
11653           cast<CXXConversionDecl>(MethodDecl->getFirstDecl());
11654       if (Conversion->isLambdaToBlockPointerConversion())
11655         DefineImplicitLambdaToBlockPointerConversion(Loc, Conversion);
11656       else
11657         DefineImplicitLambdaToFunctionPointerConversion(Loc, Conversion);
11658     } else if (MethodDecl->isVirtual())
11659       MarkVTableUsed(Loc, MethodDecl->getParent());
11660   }
11661 
11662   // Recursive functions should be marked when used from another function.
11663   // FIXME: Is this really right?
11664   if (CurContext == Func) return;
11665 
11666   // Resolve the exception specification for any function which is
11667   // used: CodeGen will need it.
11668   const FunctionProtoType *FPT = Func->getType()->getAs<FunctionProtoType>();
11669   if (FPT && isUnresolvedExceptionSpec(FPT->getExceptionSpecType()))
11670     ResolveExceptionSpec(Loc, FPT);
11671 
11672   if (!OdrUse) return;
11673 
11674   // Implicit instantiation of function templates and member functions of
11675   // class templates.
11676   if (Func->isImplicitlyInstantiable()) {
11677     bool AlreadyInstantiated = false;
11678     SourceLocation PointOfInstantiation = Loc;
11679     if (FunctionTemplateSpecializationInfo *SpecInfo
11680                               = Func->getTemplateSpecializationInfo()) {
11681       if (SpecInfo->getPointOfInstantiation().isInvalid())
11682         SpecInfo->setPointOfInstantiation(Loc);
11683       else if (SpecInfo->getTemplateSpecializationKind()
11684                  == TSK_ImplicitInstantiation) {
11685         AlreadyInstantiated = true;
11686         PointOfInstantiation = SpecInfo->getPointOfInstantiation();
11687       }
11688     } else if (MemberSpecializationInfo *MSInfo
11689                                 = Func->getMemberSpecializationInfo()) {
11690       if (MSInfo->getPointOfInstantiation().isInvalid())
11691         MSInfo->setPointOfInstantiation(Loc);
11692       else if (MSInfo->getTemplateSpecializationKind()
11693                  == TSK_ImplicitInstantiation) {
11694         AlreadyInstantiated = true;
11695         PointOfInstantiation = MSInfo->getPointOfInstantiation();
11696       }
11697     }
11698 
11699     if (!AlreadyInstantiated || Func->isConstexpr()) {
11700       if (isa<CXXRecordDecl>(Func->getDeclContext()) &&
11701           cast<CXXRecordDecl>(Func->getDeclContext())->isLocalClass() &&
11702           ActiveTemplateInstantiations.size())
11703         PendingLocalImplicitInstantiations.push_back(
11704             std::make_pair(Func, PointOfInstantiation));
11705       else if (Func->isConstexpr())
11706         // Do not defer instantiations of constexpr functions, to avoid the
11707         // expression evaluator needing to call back into Sema if it sees a
11708         // call to such a function.
11709         InstantiateFunctionDefinition(PointOfInstantiation, Func);
11710       else {
11711         PendingInstantiations.push_back(std::make_pair(Func,
11712                                                        PointOfInstantiation));
11713         // Notify the consumer that a function was implicitly instantiated.
11714         Consumer.HandleCXXImplicitFunctionInstantiation(Func);
11715       }
11716     }
11717   } else {
11718     // Walk redefinitions, as some of them may be instantiable.
11719     for (auto i : Func->redecls()) {
11720       if (!i->isUsed(false) && i->isImplicitlyInstantiable())
11721         MarkFunctionReferenced(Loc, i);
11722     }
11723   }
11724 
11725   // Keep track of used but undefined functions.
11726   if (!Func->isDefined()) {
11727     if (mightHaveNonExternalLinkage(Func))
11728       UndefinedButUsed.insert(std::make_pair(Func->getCanonicalDecl(), Loc));
11729     else if (Func->getMostRecentDecl()->isInlined() &&
11730              (LangOpts.CPlusPlus || !LangOpts.GNUInline) &&
11731              !Func->getMostRecentDecl()->hasAttr<GNUInlineAttr>())
11732       UndefinedButUsed.insert(std::make_pair(Func->getCanonicalDecl(), Loc));
11733   }
11734 
11735   // Normally the most current decl is marked used while processing the use and
11736   // any subsequent decls are marked used by decl merging. This fails with
11737   // template instantiation since marking can happen at the end of the file
11738   // and, because of the two phase lookup, this function is called with at
11739   // decl in the middle of a decl chain. We loop to maintain the invariant
11740   // that once a decl is used, all decls after it are also used.
11741   for (FunctionDecl *F = Func->getMostRecentDecl();; F = F->getPreviousDecl()) {
11742     F->markUsed(Context);
11743     if (F == Func)
11744       break;
11745   }
11746 }
11747 
11748 static void
diagnoseUncapturableValueReference(Sema & S,SourceLocation loc,VarDecl * var,DeclContext * DC)11749 diagnoseUncapturableValueReference(Sema &S, SourceLocation loc,
11750                                    VarDecl *var, DeclContext *DC) {
11751   DeclContext *VarDC = var->getDeclContext();
11752 
11753   //  If the parameter still belongs to the translation unit, then
11754   //  we're actually just using one parameter in the declaration of
11755   //  the next.
11756   if (isa<ParmVarDecl>(var) &&
11757       isa<TranslationUnitDecl>(VarDC))
11758     return;
11759 
11760   // For C code, don't diagnose about capture if we're not actually in code
11761   // right now; it's impossible to write a non-constant expression outside of
11762   // function context, so we'll get other (more useful) diagnostics later.
11763   //
11764   // For C++, things get a bit more nasty... it would be nice to suppress this
11765   // diagnostic for certain cases like using a local variable in an array bound
11766   // for a member of a local class, but the correct predicate is not obvious.
11767   if (!S.getLangOpts().CPlusPlus && !S.CurContext->isFunctionOrMethod())
11768     return;
11769 
11770   if (isa<CXXMethodDecl>(VarDC) &&
11771       cast<CXXRecordDecl>(VarDC->getParent())->isLambda()) {
11772     S.Diag(loc, diag::err_reference_to_local_var_in_enclosing_lambda)
11773       << var->getIdentifier();
11774   } else if (FunctionDecl *fn = dyn_cast<FunctionDecl>(VarDC)) {
11775     S.Diag(loc, diag::err_reference_to_local_var_in_enclosing_function)
11776       << var->getIdentifier() << fn->getDeclName();
11777   } else if (isa<BlockDecl>(VarDC)) {
11778     S.Diag(loc, diag::err_reference_to_local_var_in_enclosing_block)
11779       << var->getIdentifier();
11780   } else {
11781     // FIXME: Is there any other context where a local variable can be
11782     // declared?
11783     S.Diag(loc, diag::err_reference_to_local_var_in_enclosing_context)
11784       << var->getIdentifier();
11785   }
11786 
11787   S.Diag(var->getLocation(), diag::note_entity_declared_at)
11788       << var->getIdentifier();
11789 
11790   // FIXME: Add additional diagnostic info about class etc. which prevents
11791   // capture.
11792 }
11793 
11794 
isVariableAlreadyCapturedInScopeInfo(CapturingScopeInfo * CSI,VarDecl * Var,bool & SubCapturesAreNested,QualType & CaptureType,QualType & DeclRefType)11795 static bool isVariableAlreadyCapturedInScopeInfo(CapturingScopeInfo *CSI, VarDecl *Var,
11796                                       bool &SubCapturesAreNested,
11797                                       QualType &CaptureType,
11798                                       QualType &DeclRefType) {
11799    // Check whether we've already captured it.
11800   if (CSI->CaptureMap.count(Var)) {
11801     // If we found a capture, any subcaptures are nested.
11802     SubCapturesAreNested = true;
11803 
11804     // Retrieve the capture type for this variable.
11805     CaptureType = CSI->getCapture(Var).getCaptureType();
11806 
11807     // Compute the type of an expression that refers to this variable.
11808     DeclRefType = CaptureType.getNonReferenceType();
11809 
11810     const CapturingScopeInfo::Capture &Cap = CSI->getCapture(Var);
11811     if (Cap.isCopyCapture() &&
11812         !(isa<LambdaScopeInfo>(CSI) && cast<LambdaScopeInfo>(CSI)->Mutable))
11813       DeclRefType.addConst();
11814     return true;
11815   }
11816   return false;
11817 }
11818 
11819 // Only block literals, captured statements, and lambda expressions can
11820 // capture; other scopes don't work.
getParentOfCapturingContextOrNull(DeclContext * DC,VarDecl * Var,SourceLocation Loc,const bool Diagnose,Sema & S)11821 static DeclContext *getParentOfCapturingContextOrNull(DeclContext *DC, VarDecl *Var,
11822                                  SourceLocation Loc,
11823                                  const bool Diagnose, Sema &S) {
11824   if (isa<BlockDecl>(DC) || isa<CapturedDecl>(DC) || isLambdaCallOperator(DC))
11825     return getLambdaAwareParentOfDeclContext(DC);
11826   else if (Var->hasLocalStorage()) {
11827     if (Diagnose)
11828        diagnoseUncapturableValueReference(S, Loc, Var, DC);
11829   }
11830   return nullptr;
11831 }
11832 
11833 // Certain capturing entities (lambdas, blocks etc.) are not allowed to capture
11834 // certain types of variables (unnamed, variably modified types etc.)
11835 // so check for eligibility.
isVariableCapturable(CapturingScopeInfo * CSI,VarDecl * Var,SourceLocation Loc,const bool Diagnose,Sema & S)11836 static bool isVariableCapturable(CapturingScopeInfo *CSI, VarDecl *Var,
11837                                  SourceLocation Loc,
11838                                  const bool Diagnose, Sema &S) {
11839 
11840   bool IsBlock = isa<BlockScopeInfo>(CSI);
11841   bool IsLambda = isa<LambdaScopeInfo>(CSI);
11842 
11843   // Lambdas are not allowed to capture unnamed variables
11844   // (e.g. anonymous unions).
11845   // FIXME: The C++11 rule don't actually state this explicitly, but I'm
11846   // assuming that's the intent.
11847   if (IsLambda && !Var->getDeclName()) {
11848     if (Diagnose) {
11849       S.Diag(Loc, diag::err_lambda_capture_anonymous_var);
11850       S.Diag(Var->getLocation(), diag::note_declared_at);
11851     }
11852     return false;
11853   }
11854 
11855   // Prohibit variably-modified types in blocks; they're difficult to deal with.
11856   if (Var->getType()->isVariablyModifiedType() && IsBlock) {
11857     if (Diagnose) {
11858       S.Diag(Loc, diag::err_ref_vm_type);
11859       S.Diag(Var->getLocation(), diag::note_previous_decl)
11860         << Var->getDeclName();
11861     }
11862     return false;
11863   }
11864   // Prohibit structs with flexible array members too.
11865   // We cannot capture what is in the tail end of the struct.
11866   if (const RecordType *VTTy = Var->getType()->getAs<RecordType>()) {
11867     if (VTTy->getDecl()->hasFlexibleArrayMember()) {
11868       if (Diagnose) {
11869         if (IsBlock)
11870           S.Diag(Loc, diag::err_ref_flexarray_type);
11871         else
11872           S.Diag(Loc, diag::err_lambda_capture_flexarray_type)
11873             << Var->getDeclName();
11874         S.Diag(Var->getLocation(), diag::note_previous_decl)
11875           << Var->getDeclName();
11876       }
11877       return false;
11878     }
11879   }
11880   const bool HasBlocksAttr = Var->hasAttr<BlocksAttr>();
11881   // Lambdas and captured statements are not allowed to capture __block
11882   // variables; they don't support the expected semantics.
11883   if (HasBlocksAttr && (IsLambda || isa<CapturedRegionScopeInfo>(CSI))) {
11884     if (Diagnose) {
11885       S.Diag(Loc, diag::err_capture_block_variable)
11886         << Var->getDeclName() << !IsLambda;
11887       S.Diag(Var->getLocation(), diag::note_previous_decl)
11888         << Var->getDeclName();
11889     }
11890     return false;
11891   }
11892 
11893   return true;
11894 }
11895 
11896 // Returns true if the capture by block was successful.
captureInBlock(BlockScopeInfo * BSI,VarDecl * Var,SourceLocation Loc,const bool BuildAndDiagnose,QualType & CaptureType,QualType & DeclRefType,const bool Nested,Sema & S)11897 static bool captureInBlock(BlockScopeInfo *BSI, VarDecl *Var,
11898                                  SourceLocation Loc,
11899                                  const bool BuildAndDiagnose,
11900                                  QualType &CaptureType,
11901                                  QualType &DeclRefType,
11902                                  const bool Nested,
11903                                  Sema &S) {
11904   Expr *CopyExpr = nullptr;
11905   bool ByRef = false;
11906 
11907   // Blocks are not allowed to capture arrays.
11908   if (CaptureType->isArrayType()) {
11909     if (BuildAndDiagnose) {
11910       S.Diag(Loc, diag::err_ref_array_type);
11911       S.Diag(Var->getLocation(), diag::note_previous_decl)
11912       << Var->getDeclName();
11913     }
11914     return false;
11915   }
11916 
11917   // Forbid the block-capture of autoreleasing variables.
11918   if (CaptureType.getObjCLifetime() == Qualifiers::OCL_Autoreleasing) {
11919     if (BuildAndDiagnose) {
11920       S.Diag(Loc, diag::err_arc_autoreleasing_capture)
11921         << /*block*/ 0;
11922       S.Diag(Var->getLocation(), diag::note_previous_decl)
11923         << Var->getDeclName();
11924     }
11925     return false;
11926   }
11927   const bool HasBlocksAttr = Var->hasAttr<BlocksAttr>();
11928   if (HasBlocksAttr || CaptureType->isReferenceType()) {
11929     // Block capture by reference does not change the capture or
11930     // declaration reference types.
11931     ByRef = true;
11932   } else {
11933     // Block capture by copy introduces 'const'.
11934     CaptureType = CaptureType.getNonReferenceType().withConst();
11935     DeclRefType = CaptureType;
11936 
11937     if (S.getLangOpts().CPlusPlus && BuildAndDiagnose) {
11938       if (const RecordType *Record = DeclRefType->getAs<RecordType>()) {
11939         // The capture logic needs the destructor, so make sure we mark it.
11940         // Usually this is unnecessary because most local variables have
11941         // their destructors marked at declaration time, but parameters are
11942         // an exception because it's technically only the call site that
11943         // actually requires the destructor.
11944         if (isa<ParmVarDecl>(Var))
11945           S.FinalizeVarWithDestructor(Var, Record);
11946 
11947         // Enter a new evaluation context to insulate the copy
11948         // full-expression.
11949         EnterExpressionEvaluationContext scope(S, S.PotentiallyEvaluated);
11950 
11951         // According to the blocks spec, the capture of a variable from
11952         // the stack requires a const copy constructor.  This is not true
11953         // of the copy/move done to move a __block variable to the heap.
11954         Expr *DeclRef = new (S.Context) DeclRefExpr(Var, Nested,
11955                                                   DeclRefType.withConst(),
11956                                                   VK_LValue, Loc);
11957 
11958         ExprResult Result
11959           = S.PerformCopyInitialization(
11960               InitializedEntity::InitializeBlock(Var->getLocation(),
11961                                                   CaptureType, false),
11962               Loc, DeclRef);
11963 
11964         // Build a full-expression copy expression if initialization
11965         // succeeded and used a non-trivial constructor.  Recover from
11966         // errors by pretending that the copy isn't necessary.
11967         if (!Result.isInvalid() &&
11968             !cast<CXXConstructExpr>(Result.get())->getConstructor()
11969                 ->isTrivial()) {
11970           Result = S.MaybeCreateExprWithCleanups(Result);
11971           CopyExpr = Result.get();
11972         }
11973       }
11974     }
11975   }
11976 
11977   // Actually capture the variable.
11978   if (BuildAndDiagnose)
11979     BSI->addCapture(Var, HasBlocksAttr, ByRef, Nested, Loc,
11980                     SourceLocation(), CaptureType, CopyExpr);
11981 
11982   return true;
11983 
11984 }
11985 
11986 
11987 /// \brief Capture the given variable in the captured region.
captureInCapturedRegion(CapturedRegionScopeInfo * RSI,VarDecl * Var,SourceLocation Loc,const bool BuildAndDiagnose,QualType & CaptureType,QualType & DeclRefType,const bool RefersToCapturedVariable,Sema & S)11988 static bool captureInCapturedRegion(CapturedRegionScopeInfo *RSI,
11989                                     VarDecl *Var,
11990                                     SourceLocation Loc,
11991                                     const bool BuildAndDiagnose,
11992                                     QualType &CaptureType,
11993                                     QualType &DeclRefType,
11994                                     const bool RefersToCapturedVariable,
11995                                     Sema &S) {
11996 
11997   // By default, capture variables by reference.
11998   bool ByRef = true;
11999   // Using an LValue reference type is consistent with Lambdas (see below).
12000   CaptureType = S.Context.getLValueReferenceType(DeclRefType);
12001   Expr *CopyExpr = nullptr;
12002   if (BuildAndDiagnose) {
12003     // The current implementation assumes that all variables are captured
12004     // by references. Since there is no capture by copy, no expression
12005     // evaluation will be needed.
12006     RecordDecl *RD = RSI->TheRecordDecl;
12007 
12008     FieldDecl *Field
12009       = FieldDecl::Create(S.Context, RD, Loc, Loc, nullptr, CaptureType,
12010                           S.Context.getTrivialTypeSourceInfo(CaptureType, Loc),
12011                           nullptr, false, ICIS_NoInit);
12012     Field->setImplicit(true);
12013     Field->setAccess(AS_private);
12014     RD->addDecl(Field);
12015 
12016     CopyExpr = new (S.Context) DeclRefExpr(Var, RefersToCapturedVariable,
12017                                             DeclRefType, VK_LValue, Loc);
12018     Var->setReferenced(true);
12019     Var->markUsed(S.Context);
12020   }
12021 
12022   // Actually capture the variable.
12023   if (BuildAndDiagnose)
12024     RSI->addCapture(Var, /*isBlock*/false, ByRef, RefersToCapturedVariable, Loc,
12025                     SourceLocation(), CaptureType, CopyExpr);
12026 
12027 
12028   return true;
12029 }
12030 
12031 /// \brief Create a field within the lambda class for the variable
12032 ///  being captured.  Handle Array captures.
addAsFieldToClosureType(Sema & S,LambdaScopeInfo * LSI,VarDecl * Var,QualType FieldType,QualType DeclRefType,SourceLocation Loc,bool RefersToCapturedVariable)12033 static ExprResult addAsFieldToClosureType(Sema &S,
12034                                  LambdaScopeInfo *LSI,
12035                                   VarDecl *Var, QualType FieldType,
12036                                   QualType DeclRefType,
12037                                   SourceLocation Loc,
12038                                   bool RefersToCapturedVariable) {
12039   CXXRecordDecl *Lambda = LSI->Lambda;
12040 
12041   // Build the non-static data member.
12042   FieldDecl *Field
12043     = FieldDecl::Create(S.Context, Lambda, Loc, Loc, nullptr, FieldType,
12044                         S.Context.getTrivialTypeSourceInfo(FieldType, Loc),
12045                         nullptr, false, ICIS_NoInit);
12046   Field->setImplicit(true);
12047   Field->setAccess(AS_private);
12048   Lambda->addDecl(Field);
12049 
12050   // C++11 [expr.prim.lambda]p21:
12051   //   When the lambda-expression is evaluated, the entities that
12052   //   are captured by copy are used to direct-initialize each
12053   //   corresponding non-static data member of the resulting closure
12054   //   object. (For array members, the array elements are
12055   //   direct-initialized in increasing subscript order.) These
12056   //   initializations are performed in the (unspecified) order in
12057   //   which the non-static data members are declared.
12058 
12059   // Introduce a new evaluation context for the initialization, so
12060   // that temporaries introduced as part of the capture are retained
12061   // to be re-"exported" from the lambda expression itself.
12062   EnterExpressionEvaluationContext scope(S, Sema::PotentiallyEvaluated);
12063 
12064   // C++ [expr.prim.labda]p12:
12065   //   An entity captured by a lambda-expression is odr-used (3.2) in
12066   //   the scope containing the lambda-expression.
12067   Expr *Ref = new (S.Context) DeclRefExpr(Var, RefersToCapturedVariable,
12068                                           DeclRefType, VK_LValue, Loc);
12069   Var->setReferenced(true);
12070   Var->markUsed(S.Context);
12071 
12072   // When the field has array type, create index variables for each
12073   // dimension of the array. We use these index variables to subscript
12074   // the source array, and other clients (e.g., CodeGen) will perform
12075   // the necessary iteration with these index variables.
12076   SmallVector<VarDecl *, 4> IndexVariables;
12077   QualType BaseType = FieldType;
12078   QualType SizeType = S.Context.getSizeType();
12079   LSI->ArrayIndexStarts.push_back(LSI->ArrayIndexVars.size());
12080   while (const ConstantArrayType *Array
12081                         = S.Context.getAsConstantArrayType(BaseType)) {
12082     // Create the iteration variable for this array index.
12083     IdentifierInfo *IterationVarName = nullptr;
12084     {
12085       SmallString<8> Str;
12086       llvm::raw_svector_ostream OS(Str);
12087       OS << "__i" << IndexVariables.size();
12088       IterationVarName = &S.Context.Idents.get(OS.str());
12089     }
12090     VarDecl *IterationVar
12091       = VarDecl::Create(S.Context, S.CurContext, Loc, Loc,
12092                         IterationVarName, SizeType,
12093                         S.Context.getTrivialTypeSourceInfo(SizeType, Loc),
12094                         SC_None);
12095     IndexVariables.push_back(IterationVar);
12096     LSI->ArrayIndexVars.push_back(IterationVar);
12097 
12098     // Create a reference to the iteration variable.
12099     ExprResult IterationVarRef
12100       = S.BuildDeclRefExpr(IterationVar, SizeType, VK_LValue, Loc);
12101     assert(!IterationVarRef.isInvalid() &&
12102            "Reference to invented variable cannot fail!");
12103     IterationVarRef = S.DefaultLvalueConversion(IterationVarRef.get());
12104     assert(!IterationVarRef.isInvalid() &&
12105            "Conversion of invented variable cannot fail!");
12106 
12107     // Subscript the array with this iteration variable.
12108     ExprResult Subscript = S.CreateBuiltinArraySubscriptExpr(
12109                              Ref, Loc, IterationVarRef.get(), Loc);
12110     if (Subscript.isInvalid()) {
12111       S.CleanupVarDeclMarking();
12112       S.DiscardCleanupsInEvaluationContext();
12113       return ExprError();
12114     }
12115 
12116     Ref = Subscript.get();
12117     BaseType = Array->getElementType();
12118   }
12119 
12120   // Construct the entity that we will be initializing. For an array, this
12121   // will be first element in the array, which may require several levels
12122   // of array-subscript entities.
12123   SmallVector<InitializedEntity, 4> Entities;
12124   Entities.reserve(1 + IndexVariables.size());
12125   Entities.push_back(
12126     InitializedEntity::InitializeLambdaCapture(Var->getIdentifier(),
12127         Field->getType(), Loc));
12128   for (unsigned I = 0, N = IndexVariables.size(); I != N; ++I)
12129     Entities.push_back(InitializedEntity::InitializeElement(S.Context,
12130                                                             0,
12131                                                             Entities.back()));
12132 
12133   InitializationKind InitKind
12134     = InitializationKind::CreateDirect(Loc, Loc, Loc);
12135   InitializationSequence Init(S, Entities.back(), InitKind, Ref);
12136   ExprResult Result(true);
12137   if (!Init.Diagnose(S, Entities.back(), InitKind, Ref))
12138     Result = Init.Perform(S, Entities.back(), InitKind, Ref);
12139 
12140   // If this initialization requires any cleanups (e.g., due to a
12141   // default argument to a copy constructor), note that for the
12142   // lambda.
12143   if (S.ExprNeedsCleanups)
12144     LSI->ExprNeedsCleanups = true;
12145 
12146   // Exit the expression evaluation context used for the capture.
12147   S.CleanupVarDeclMarking();
12148   S.DiscardCleanupsInEvaluationContext();
12149   return Result;
12150 }
12151 
12152 
12153 
12154 /// \brief Capture the given variable in the lambda.
captureInLambda(LambdaScopeInfo * LSI,VarDecl * Var,SourceLocation Loc,const bool BuildAndDiagnose,QualType & CaptureType,QualType & DeclRefType,const bool RefersToCapturedVariable,const Sema::TryCaptureKind Kind,SourceLocation EllipsisLoc,const bool IsTopScope,Sema & S)12155 static bool captureInLambda(LambdaScopeInfo *LSI,
12156                             VarDecl *Var,
12157                             SourceLocation Loc,
12158                             const bool BuildAndDiagnose,
12159                             QualType &CaptureType,
12160                             QualType &DeclRefType,
12161                             const bool RefersToCapturedVariable,
12162                             const Sema::TryCaptureKind Kind,
12163                             SourceLocation EllipsisLoc,
12164                             const bool IsTopScope,
12165                             Sema &S) {
12166 
12167   // Determine whether we are capturing by reference or by value.
12168   bool ByRef = false;
12169   if (IsTopScope && Kind != Sema::TryCapture_Implicit) {
12170     ByRef = (Kind == Sema::TryCapture_ExplicitByRef);
12171   } else {
12172     ByRef = (LSI->ImpCaptureStyle == LambdaScopeInfo::ImpCap_LambdaByref);
12173   }
12174 
12175   // Compute the type of the field that will capture this variable.
12176   if (ByRef) {
12177     // C++11 [expr.prim.lambda]p15:
12178     //   An entity is captured by reference if it is implicitly or
12179     //   explicitly captured but not captured by copy. It is
12180     //   unspecified whether additional unnamed non-static data
12181     //   members are declared in the closure type for entities
12182     //   captured by reference.
12183     //
12184     // FIXME: It is not clear whether we want to build an lvalue reference
12185     // to the DeclRefType or to CaptureType.getNonReferenceType(). GCC appears
12186     // to do the former, while EDG does the latter. Core issue 1249 will
12187     // clarify, but for now we follow GCC because it's a more permissive and
12188     // easily defensible position.
12189     CaptureType = S.Context.getLValueReferenceType(DeclRefType);
12190   } else {
12191     // C++11 [expr.prim.lambda]p14:
12192     //   For each entity captured by copy, an unnamed non-static
12193     //   data member is declared in the closure type. The
12194     //   declaration order of these members is unspecified. The type
12195     //   of such a data member is the type of the corresponding
12196     //   captured entity if the entity is not a reference to an
12197     //   object, or the referenced type otherwise. [Note: If the
12198     //   captured entity is a reference to a function, the
12199     //   corresponding data member is also a reference to a
12200     //   function. - end note ]
12201     if (const ReferenceType *RefType = CaptureType->getAs<ReferenceType>()){
12202       if (!RefType->getPointeeType()->isFunctionType())
12203         CaptureType = RefType->getPointeeType();
12204     }
12205 
12206     // Forbid the lambda copy-capture of autoreleasing variables.
12207     if (CaptureType.getObjCLifetime() == Qualifiers::OCL_Autoreleasing) {
12208       if (BuildAndDiagnose) {
12209         S.Diag(Loc, diag::err_arc_autoreleasing_capture) << /*lambda*/ 1;
12210         S.Diag(Var->getLocation(), diag::note_previous_decl)
12211           << Var->getDeclName();
12212       }
12213       return false;
12214     }
12215 
12216     // Make sure that by-copy captures are of a complete and non-abstract type.
12217     if (BuildAndDiagnose) {
12218       if (!CaptureType->isDependentType() &&
12219           S.RequireCompleteType(Loc, CaptureType,
12220                                 diag::err_capture_of_incomplete_type,
12221                                 Var->getDeclName()))
12222         return false;
12223 
12224       if (S.RequireNonAbstractType(Loc, CaptureType,
12225                                    diag::err_capture_of_abstract_type))
12226         return false;
12227     }
12228   }
12229 
12230   // Capture this variable in the lambda.
12231   Expr *CopyExpr = nullptr;
12232   if (BuildAndDiagnose) {
12233     ExprResult Result = addAsFieldToClosureType(S, LSI, Var,
12234                                         CaptureType, DeclRefType, Loc,
12235                                         RefersToCapturedVariable);
12236     if (!Result.isInvalid())
12237       CopyExpr = Result.get();
12238   }
12239 
12240   // Compute the type of a reference to this captured variable.
12241   if (ByRef)
12242     DeclRefType = CaptureType.getNonReferenceType();
12243   else {
12244     // C++ [expr.prim.lambda]p5:
12245     //   The closure type for a lambda-expression has a public inline
12246     //   function call operator [...]. This function call operator is
12247     //   declared const (9.3.1) if and only if the lambda-expression’s
12248     //   parameter-declaration-clause is not followed by mutable.
12249     DeclRefType = CaptureType.getNonReferenceType();
12250     if (!LSI->Mutable && !CaptureType->isReferenceType())
12251       DeclRefType.addConst();
12252   }
12253 
12254   // Add the capture.
12255   if (BuildAndDiagnose)
12256     LSI->addCapture(Var, /*IsBlock=*/false, ByRef, RefersToCapturedVariable,
12257                     Loc, EllipsisLoc, CaptureType, CopyExpr);
12258 
12259   return true;
12260 }
12261 
tryCaptureVariable(VarDecl * Var,SourceLocation ExprLoc,TryCaptureKind Kind,SourceLocation EllipsisLoc,bool BuildAndDiagnose,QualType & CaptureType,QualType & DeclRefType,const unsigned * const FunctionScopeIndexToStopAt)12262 bool Sema::tryCaptureVariable(VarDecl *Var, SourceLocation ExprLoc,
12263                               TryCaptureKind Kind, SourceLocation EllipsisLoc,
12264                               bool BuildAndDiagnose,
12265                               QualType &CaptureType,
12266                               QualType &DeclRefType,
12267 						                const unsigned *const FunctionScopeIndexToStopAt) {
12268   bool Nested = Var->isInitCapture();
12269 
12270   DeclContext *DC = CurContext;
12271   const unsigned MaxFunctionScopesIndex = FunctionScopeIndexToStopAt
12272       ? *FunctionScopeIndexToStopAt : FunctionScopes.size() - 1;
12273   // We need to sync up the Declaration Context with the
12274   // FunctionScopeIndexToStopAt
12275   if (FunctionScopeIndexToStopAt) {
12276     unsigned FSIndex = FunctionScopes.size() - 1;
12277     while (FSIndex != MaxFunctionScopesIndex) {
12278       DC = getLambdaAwareParentOfDeclContext(DC);
12279       --FSIndex;
12280     }
12281   }
12282 
12283 
12284   // If the variable is declared in the current context (and is not an
12285   // init-capture), there is no need to capture it.
12286   if (!Nested && Var->getDeclContext() == DC) return true;
12287 
12288   // Capture global variables if it is required to use private copy of this
12289   // variable.
12290   bool IsGlobal = !Var->hasLocalStorage();
12291   if (IsGlobal && !(LangOpts.OpenMP && IsOpenMPCapturedVar(Var)))
12292     return true;
12293 
12294   // Walk up the stack to determine whether we can capture the variable,
12295   // performing the "simple" checks that don't depend on type. We stop when
12296   // we've either hit the declared scope of the variable or find an existing
12297   // capture of that variable.  We start from the innermost capturing-entity
12298   // (the DC) and ensure that all intervening capturing-entities
12299   // (blocks/lambdas etc.) between the innermost capturer and the variable`s
12300   // declcontext can either capture the variable or have already captured
12301   // the variable.
12302   CaptureType = Var->getType();
12303   DeclRefType = CaptureType.getNonReferenceType();
12304   bool Explicit = (Kind != TryCapture_Implicit);
12305   unsigned FunctionScopesIndex = MaxFunctionScopesIndex;
12306   do {
12307     // Only block literals, captured statements, and lambda expressions can
12308     // capture; other scopes don't work.
12309     DeclContext *ParentDC = getParentOfCapturingContextOrNull(DC, Var,
12310                                                               ExprLoc,
12311                                                               BuildAndDiagnose,
12312                                                               *this);
12313     // We need to check for the parent *first* because, if we *have*
12314     // private-captured a global variable, we need to recursively capture it in
12315     // intermediate blocks, lambdas, etc.
12316     if (!ParentDC) {
12317       if (IsGlobal) {
12318         FunctionScopesIndex = MaxFunctionScopesIndex - 1;
12319         break;
12320       }
12321       return true;
12322     }
12323 
12324     FunctionScopeInfo  *FSI = FunctionScopes[FunctionScopesIndex];
12325     CapturingScopeInfo *CSI = cast<CapturingScopeInfo>(FSI);
12326 
12327 
12328     // Check whether we've already captured it.
12329     if (isVariableAlreadyCapturedInScopeInfo(CSI, Var, Nested, CaptureType,
12330                                              DeclRefType))
12331       break;
12332     // If we are instantiating a generic lambda call operator body,
12333     // we do not want to capture new variables.  What was captured
12334     // during either a lambdas transformation or initial parsing
12335     // should be used.
12336     if (isGenericLambdaCallOperatorSpecialization(DC)) {
12337       if (BuildAndDiagnose) {
12338         LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(CSI);
12339         if (LSI->ImpCaptureStyle == CapturingScopeInfo::ImpCap_None) {
12340           Diag(ExprLoc, diag::err_lambda_impcap) << Var->getDeclName();
12341           Diag(Var->getLocation(), diag::note_previous_decl)
12342              << Var->getDeclName();
12343           Diag(LSI->Lambda->getLocStart(), diag::note_lambda_decl);
12344         } else
12345           diagnoseUncapturableValueReference(*this, ExprLoc, Var, DC);
12346       }
12347       return true;
12348     }
12349     // Certain capturing entities (lambdas, blocks etc.) are not allowed to capture
12350     // certain types of variables (unnamed, variably modified types etc.)
12351     // so check for eligibility.
12352     if (!isVariableCapturable(CSI, Var, ExprLoc, BuildAndDiagnose, *this))
12353        return true;
12354 
12355     // Try to capture variable-length arrays types.
12356     if (Var->getType()->isVariablyModifiedType()) {
12357       // We're going to walk down into the type and look for VLA
12358       // expressions.
12359       QualType QTy = Var->getType();
12360       if (ParmVarDecl *PVD = dyn_cast_or_null<ParmVarDecl>(Var))
12361         QTy = PVD->getOriginalType();
12362       do {
12363         const Type *Ty = QTy.getTypePtr();
12364         switch (Ty->getTypeClass()) {
12365 #define TYPE(Class, Base)
12366 #define ABSTRACT_TYPE(Class, Base)
12367 #define NON_CANONICAL_TYPE(Class, Base)
12368 #define DEPENDENT_TYPE(Class, Base) case Type::Class:
12369 #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base)
12370 #include "clang/AST/TypeNodes.def"
12371           QTy = QualType();
12372           break;
12373         // These types are never variably-modified.
12374         case Type::Builtin:
12375         case Type::Complex:
12376         case Type::Vector:
12377         case Type::ExtVector:
12378         case Type::Record:
12379         case Type::Enum:
12380         case Type::Elaborated:
12381         case Type::TemplateSpecialization:
12382         case Type::ObjCObject:
12383         case Type::ObjCInterface:
12384         case Type::ObjCObjectPointer:
12385           llvm_unreachable("type class is never variably-modified!");
12386         case Type::Adjusted:
12387           QTy = cast<AdjustedType>(Ty)->getOriginalType();
12388           break;
12389         case Type::Decayed:
12390           QTy = cast<DecayedType>(Ty)->getPointeeType();
12391           break;
12392         case Type::Pointer:
12393           QTy = cast<PointerType>(Ty)->getPointeeType();
12394           break;
12395         case Type::BlockPointer:
12396           QTy = cast<BlockPointerType>(Ty)->getPointeeType();
12397           break;
12398         case Type::LValueReference:
12399         case Type::RValueReference:
12400           QTy = cast<ReferenceType>(Ty)->getPointeeType();
12401           break;
12402         case Type::MemberPointer:
12403           QTy = cast<MemberPointerType>(Ty)->getPointeeType();
12404           break;
12405         case Type::ConstantArray:
12406         case Type::IncompleteArray:
12407           // Losing element qualification here is fine.
12408           QTy = cast<ArrayType>(Ty)->getElementType();
12409           break;
12410         case Type::VariableArray: {
12411           // Losing element qualification here is fine.
12412           const VariableArrayType *VAT = cast<VariableArrayType>(Ty);
12413 
12414           // Unknown size indication requires no size computation.
12415           // Otherwise, evaluate and record it.
12416           if (auto Size = VAT->getSizeExpr()) {
12417             if (!CSI->isVLATypeCaptured(VAT)) {
12418               RecordDecl *CapRecord = nullptr;
12419               if (auto LSI = dyn_cast<LambdaScopeInfo>(CSI)) {
12420                 CapRecord = LSI->Lambda;
12421               } else if (auto CRSI = dyn_cast<CapturedRegionScopeInfo>(CSI)) {
12422                 CapRecord = CRSI->TheRecordDecl;
12423               }
12424               if (CapRecord) {
12425                 auto ExprLoc = Size->getExprLoc();
12426                 auto SizeType = Context.getSizeType();
12427                 // Build the non-static data member.
12428                 auto Field = FieldDecl::Create(
12429                     Context, CapRecord, ExprLoc, ExprLoc,
12430                     /*Id*/ nullptr, SizeType, /*TInfo*/ nullptr,
12431                     /*BW*/ nullptr, /*Mutable*/ false,
12432                     /*InitStyle*/ ICIS_NoInit);
12433                 Field->setImplicit(true);
12434                 Field->setAccess(AS_private);
12435                 Field->setCapturedVLAType(VAT);
12436                 CapRecord->addDecl(Field);
12437 
12438                 CSI->addVLATypeCapture(ExprLoc, SizeType);
12439               }
12440             }
12441           }
12442           QTy = VAT->getElementType();
12443           break;
12444         }
12445         case Type::FunctionProto:
12446         case Type::FunctionNoProto:
12447           QTy = cast<FunctionType>(Ty)->getReturnType();
12448           break;
12449         case Type::Paren:
12450         case Type::TypeOf:
12451         case Type::UnaryTransform:
12452         case Type::Attributed:
12453         case Type::SubstTemplateTypeParm:
12454         case Type::PackExpansion:
12455           // Keep walking after single level desugaring.
12456           QTy = QTy.getSingleStepDesugaredType(getASTContext());
12457           break;
12458         case Type::Typedef:
12459           QTy = cast<TypedefType>(Ty)->desugar();
12460           break;
12461         case Type::Decltype:
12462           QTy = cast<DecltypeType>(Ty)->desugar();
12463           break;
12464         case Type::Auto:
12465           QTy = cast<AutoType>(Ty)->getDeducedType();
12466           break;
12467         case Type::TypeOfExpr:
12468           QTy = cast<TypeOfExprType>(Ty)->getUnderlyingExpr()->getType();
12469           break;
12470         case Type::Atomic:
12471           QTy = cast<AtomicType>(Ty)->getValueType();
12472           break;
12473         }
12474       } while (!QTy.isNull() && QTy->isVariablyModifiedType());
12475     }
12476 
12477     if (CSI->ImpCaptureStyle == CapturingScopeInfo::ImpCap_None && !Explicit) {
12478       // No capture-default, and this is not an explicit capture
12479       // so cannot capture this variable.
12480       if (BuildAndDiagnose) {
12481         Diag(ExprLoc, diag::err_lambda_impcap) << Var->getDeclName();
12482         Diag(Var->getLocation(), diag::note_previous_decl)
12483           << Var->getDeclName();
12484         Diag(cast<LambdaScopeInfo>(CSI)->Lambda->getLocStart(),
12485              diag::note_lambda_decl);
12486         // FIXME: If we error out because an outer lambda can not implicitly
12487         // capture a variable that an inner lambda explicitly captures, we
12488         // should have the inner lambda do the explicit capture - because
12489         // it makes for cleaner diagnostics later.  This would purely be done
12490         // so that the diagnostic does not misleadingly claim that a variable
12491         // can not be captured by a lambda implicitly even though it is captured
12492         // explicitly.  Suggestion:
12493         //  - create const bool VariableCaptureWasInitiallyExplicit = Explicit
12494         //    at the function head
12495         //  - cache the StartingDeclContext - this must be a lambda
12496         //  - captureInLambda in the innermost lambda the variable.
12497       }
12498       return true;
12499     }
12500 
12501     FunctionScopesIndex--;
12502     DC = ParentDC;
12503     Explicit = false;
12504   } while (!Var->getDeclContext()->Equals(DC));
12505 
12506   // Walk back down the scope stack, (e.g. from outer lambda to inner lambda)
12507   // computing the type of the capture at each step, checking type-specific
12508   // requirements, and adding captures if requested.
12509   // If the variable had already been captured previously, we start capturing
12510   // at the lambda nested within that one.
12511   for (unsigned I = ++FunctionScopesIndex, N = MaxFunctionScopesIndex + 1; I != N;
12512        ++I) {
12513     CapturingScopeInfo *CSI = cast<CapturingScopeInfo>(FunctionScopes[I]);
12514 
12515     if (BlockScopeInfo *BSI = dyn_cast<BlockScopeInfo>(CSI)) {
12516       if (!captureInBlock(BSI, Var, ExprLoc,
12517                           BuildAndDiagnose, CaptureType,
12518                           DeclRefType, Nested, *this))
12519         return true;
12520       Nested = true;
12521     } else if (CapturedRegionScopeInfo *RSI = dyn_cast<CapturedRegionScopeInfo>(CSI)) {
12522       if (!captureInCapturedRegion(RSI, Var, ExprLoc,
12523                                    BuildAndDiagnose, CaptureType,
12524                                    DeclRefType, Nested, *this))
12525         return true;
12526       Nested = true;
12527     } else {
12528       LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(CSI);
12529       if (!captureInLambda(LSI, Var, ExprLoc,
12530                            BuildAndDiagnose, CaptureType,
12531                            DeclRefType, Nested, Kind, EllipsisLoc,
12532                             /*IsTopScope*/I == N - 1, *this))
12533         return true;
12534       Nested = true;
12535     }
12536   }
12537   return false;
12538 }
12539 
tryCaptureVariable(VarDecl * Var,SourceLocation Loc,TryCaptureKind Kind,SourceLocation EllipsisLoc)12540 bool Sema::tryCaptureVariable(VarDecl *Var, SourceLocation Loc,
12541                               TryCaptureKind Kind, SourceLocation EllipsisLoc) {
12542   QualType CaptureType;
12543   QualType DeclRefType;
12544   return tryCaptureVariable(Var, Loc, Kind, EllipsisLoc,
12545                             /*BuildAndDiagnose=*/true, CaptureType,
12546                             DeclRefType, nullptr);
12547 }
12548 
NeedToCaptureVariable(VarDecl * Var,SourceLocation Loc)12549 bool Sema::NeedToCaptureVariable(VarDecl *Var, SourceLocation Loc) {
12550   QualType CaptureType;
12551   QualType DeclRefType;
12552   return !tryCaptureVariable(Var, Loc, TryCapture_Implicit, SourceLocation(),
12553                              /*BuildAndDiagnose=*/false, CaptureType,
12554                              DeclRefType, nullptr);
12555 }
12556 
getCapturedDeclRefType(VarDecl * Var,SourceLocation Loc)12557 QualType Sema::getCapturedDeclRefType(VarDecl *Var, SourceLocation Loc) {
12558   QualType CaptureType;
12559   QualType DeclRefType;
12560 
12561   // Determine whether we can capture this variable.
12562   if (tryCaptureVariable(Var, Loc, TryCapture_Implicit, SourceLocation(),
12563                          /*BuildAndDiagnose=*/false, CaptureType,
12564                          DeclRefType, nullptr))
12565     return QualType();
12566 
12567   return DeclRefType;
12568 }
12569 
12570 
12571 
12572 // If either the type of the variable or the initializer is dependent,
12573 // return false. Otherwise, determine whether the variable is a constant
12574 // expression. Use this if you need to know if a variable that might or
12575 // might not be dependent is truly a constant expression.
IsVariableNonDependentAndAConstantExpression(VarDecl * Var,ASTContext & Context)12576 static inline bool IsVariableNonDependentAndAConstantExpression(VarDecl *Var,
12577     ASTContext &Context) {
12578 
12579   if (Var->getType()->isDependentType())
12580     return false;
12581   const VarDecl *DefVD = nullptr;
12582   Var->getAnyInitializer(DefVD);
12583   if (!DefVD)
12584     return false;
12585   EvaluatedStmt *Eval = DefVD->ensureEvaluatedStmt();
12586   Expr *Init = cast<Expr>(Eval->Value);
12587   if (Init->isValueDependent())
12588     return false;
12589   return IsVariableAConstantExpression(Var, Context);
12590 }
12591 
12592 
UpdateMarkingForLValueToRValue(Expr * E)12593 void Sema::UpdateMarkingForLValueToRValue(Expr *E) {
12594   // Per C++11 [basic.def.odr], a variable is odr-used "unless it is
12595   // an object that satisfies the requirements for appearing in a
12596   // constant expression (5.19) and the lvalue-to-rvalue conversion (4.1)
12597   // is immediately applied."  This function handles the lvalue-to-rvalue
12598   // conversion part.
12599   MaybeODRUseExprs.erase(E->IgnoreParens());
12600 
12601   // If we are in a lambda, check if this DeclRefExpr or MemberExpr refers
12602   // to a variable that is a constant expression, and if so, identify it as
12603   // a reference to a variable that does not involve an odr-use of that
12604   // variable.
12605   if (LambdaScopeInfo *LSI = getCurLambda()) {
12606     Expr *SansParensExpr = E->IgnoreParens();
12607     VarDecl *Var = nullptr;
12608     if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(SansParensExpr))
12609       Var = dyn_cast<VarDecl>(DRE->getFoundDecl());
12610     else if (MemberExpr *ME = dyn_cast<MemberExpr>(SansParensExpr))
12611       Var = dyn_cast<VarDecl>(ME->getMemberDecl());
12612 
12613     if (Var && IsVariableNonDependentAndAConstantExpression(Var, Context))
12614       LSI->markVariableExprAsNonODRUsed(SansParensExpr);
12615   }
12616 }
12617 
ActOnConstantExpression(ExprResult Res)12618 ExprResult Sema::ActOnConstantExpression(ExprResult Res) {
12619   Res = CorrectDelayedTyposInExpr(Res);
12620 
12621   if (!Res.isUsable())
12622     return Res;
12623 
12624   // If a constant-expression is a reference to a variable where we delay
12625   // deciding whether it is an odr-use, just assume we will apply the
12626   // lvalue-to-rvalue conversion.  In the one case where this doesn't happen
12627   // (a non-type template argument), we have special handling anyway.
12628   UpdateMarkingForLValueToRValue(Res.get());
12629   return Res;
12630 }
12631 
CleanupVarDeclMarking()12632 void Sema::CleanupVarDeclMarking() {
12633   for (llvm::SmallPtrSetIterator<Expr*> i = MaybeODRUseExprs.begin(),
12634                                         e = MaybeODRUseExprs.end();
12635        i != e; ++i) {
12636     VarDecl *Var;
12637     SourceLocation Loc;
12638     if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(*i)) {
12639       Var = cast<VarDecl>(DRE->getDecl());
12640       Loc = DRE->getLocation();
12641     } else if (MemberExpr *ME = dyn_cast<MemberExpr>(*i)) {
12642       Var = cast<VarDecl>(ME->getMemberDecl());
12643       Loc = ME->getMemberLoc();
12644     } else {
12645       llvm_unreachable("Unexpected expression");
12646     }
12647 
12648     MarkVarDeclODRUsed(Var, Loc, *this,
12649                        /*MaxFunctionScopeIndex Pointer*/ nullptr);
12650   }
12651 
12652   MaybeODRUseExprs.clear();
12653 }
12654 
12655 
DoMarkVarDeclReferenced(Sema & SemaRef,SourceLocation Loc,VarDecl * Var,Expr * E)12656 static void DoMarkVarDeclReferenced(Sema &SemaRef, SourceLocation Loc,
12657                                     VarDecl *Var, Expr *E) {
12658   assert((!E || isa<DeclRefExpr>(E) || isa<MemberExpr>(E)) &&
12659          "Invalid Expr argument to DoMarkVarDeclReferenced");
12660   Var->setReferenced();
12661 
12662   TemplateSpecializationKind TSK = Var->getTemplateSpecializationKind();
12663   bool MarkODRUsed = true;
12664 
12665   // If the context is not potentially evaluated, this is not an odr-use and
12666   // does not trigger instantiation.
12667   if (!IsPotentiallyEvaluatedContext(SemaRef)) {
12668     if (SemaRef.isUnevaluatedContext())
12669       return;
12670 
12671     // If we don't yet know whether this context is going to end up being an
12672     // evaluated context, and we're referencing a variable from an enclosing
12673     // scope, add a potential capture.
12674     //
12675     // FIXME: Is this necessary? These contexts are only used for default
12676     // arguments, where local variables can't be used.
12677     const bool RefersToEnclosingScope =
12678         (SemaRef.CurContext != Var->getDeclContext() &&
12679          Var->getDeclContext()->isFunctionOrMethod() && Var->hasLocalStorage());
12680     if (RefersToEnclosingScope) {
12681       if (LambdaScopeInfo *const LSI = SemaRef.getCurLambda()) {
12682         // If a variable could potentially be odr-used, defer marking it so
12683         // until we finish analyzing the full expression for any
12684         // lvalue-to-rvalue
12685         // or discarded value conversions that would obviate odr-use.
12686         // Add it to the list of potential captures that will be analyzed
12687         // later (ActOnFinishFullExpr) for eventual capture and odr-use marking
12688         // unless the variable is a reference that was initialized by a constant
12689         // expression (this will never need to be captured or odr-used).
12690         assert(E && "Capture variable should be used in an expression.");
12691         if (!Var->getType()->isReferenceType() ||
12692             !IsVariableNonDependentAndAConstantExpression(Var, SemaRef.Context))
12693           LSI->addPotentialCapture(E->IgnoreParens());
12694       }
12695     }
12696 
12697     if (!isTemplateInstantiation(TSK))
12698     	return;
12699 
12700     // Instantiate, but do not mark as odr-used, variable templates.
12701     MarkODRUsed = false;
12702   }
12703 
12704   VarTemplateSpecializationDecl *VarSpec =
12705       dyn_cast<VarTemplateSpecializationDecl>(Var);
12706   assert(!isa<VarTemplatePartialSpecializationDecl>(Var) &&
12707          "Can't instantiate a partial template specialization.");
12708 
12709   // Perform implicit instantiation of static data members, static data member
12710   // templates of class templates, and variable template specializations. Delay
12711   // instantiations of variable templates, except for those that could be used
12712   // in a constant expression.
12713   if (isTemplateInstantiation(TSK)) {
12714     bool TryInstantiating = TSK == TSK_ImplicitInstantiation;
12715 
12716     if (TryInstantiating && !isa<VarTemplateSpecializationDecl>(Var)) {
12717       if (Var->getPointOfInstantiation().isInvalid()) {
12718         // This is a modification of an existing AST node. Notify listeners.
12719         if (ASTMutationListener *L = SemaRef.getASTMutationListener())
12720           L->StaticDataMemberInstantiated(Var);
12721       } else if (!Var->isUsableInConstantExpressions(SemaRef.Context))
12722         // Don't bother trying to instantiate it again, unless we might need
12723         // its initializer before we get to the end of the TU.
12724         TryInstantiating = false;
12725     }
12726 
12727     if (Var->getPointOfInstantiation().isInvalid())
12728       Var->setTemplateSpecializationKind(TSK, Loc);
12729 
12730     if (TryInstantiating) {
12731       SourceLocation PointOfInstantiation = Var->getPointOfInstantiation();
12732       bool InstantiationDependent = false;
12733       bool IsNonDependent =
12734           VarSpec ? !TemplateSpecializationType::anyDependentTemplateArguments(
12735                         VarSpec->getTemplateArgsInfo(), InstantiationDependent)
12736                   : true;
12737 
12738       // Do not instantiate specializations that are still type-dependent.
12739       if (IsNonDependent) {
12740         if (Var->isUsableInConstantExpressions(SemaRef.Context)) {
12741           // Do not defer instantiations of variables which could be used in a
12742           // constant expression.
12743           SemaRef.InstantiateVariableDefinition(PointOfInstantiation, Var);
12744         } else {
12745           SemaRef.PendingInstantiations
12746               .push_back(std::make_pair(Var, PointOfInstantiation));
12747         }
12748       }
12749     }
12750   }
12751 
12752   if(!MarkODRUsed) return;
12753 
12754   // Per C++11 [basic.def.odr], a variable is odr-used "unless it satisfies
12755   // the requirements for appearing in a constant expression (5.19) and, if
12756   // it is an object, the lvalue-to-rvalue conversion (4.1)
12757   // is immediately applied."  We check the first part here, and
12758   // Sema::UpdateMarkingForLValueToRValue deals with the second part.
12759   // Note that we use the C++11 definition everywhere because nothing in
12760   // C++03 depends on whether we get the C++03 version correct. The second
12761   // part does not apply to references, since they are not objects.
12762   if (E && IsVariableAConstantExpression(Var, SemaRef.Context)) {
12763     // A reference initialized by a constant expression can never be
12764     // odr-used, so simply ignore it.
12765     if (!Var->getType()->isReferenceType())
12766       SemaRef.MaybeODRUseExprs.insert(E);
12767   } else
12768     MarkVarDeclODRUsed(Var, Loc, SemaRef,
12769                        /*MaxFunctionScopeIndex ptr*/ nullptr);
12770 }
12771 
12772 /// \brief Mark a variable referenced, and check whether it is odr-used
12773 /// (C++ [basic.def.odr]p2, C99 6.9p3).  Note that this should not be
12774 /// used directly for normal expressions referring to VarDecl.
MarkVariableReferenced(SourceLocation Loc,VarDecl * Var)12775 void Sema::MarkVariableReferenced(SourceLocation Loc, VarDecl *Var) {
12776   DoMarkVarDeclReferenced(*this, Loc, Var, nullptr);
12777 }
12778 
MarkExprReferenced(Sema & SemaRef,SourceLocation Loc,Decl * D,Expr * E,bool OdrUse)12779 static void MarkExprReferenced(Sema &SemaRef, SourceLocation Loc,
12780                                Decl *D, Expr *E, bool OdrUse) {
12781   if (VarDecl *Var = dyn_cast<VarDecl>(D)) {
12782     DoMarkVarDeclReferenced(SemaRef, Loc, Var, E);
12783     return;
12784   }
12785 
12786   SemaRef.MarkAnyDeclReferenced(Loc, D, OdrUse);
12787 
12788   // If this is a call to a method via a cast, also mark the method in the
12789   // derived class used in case codegen can devirtualize the call.
12790   const MemberExpr *ME = dyn_cast<MemberExpr>(E);
12791   if (!ME)
12792     return;
12793   CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ME->getMemberDecl());
12794   if (!MD)
12795     return;
12796   // Only attempt to devirtualize if this is truly a virtual call.
12797   bool IsVirtualCall = MD->isVirtual() && !ME->hasQualifier();
12798   if (!IsVirtualCall)
12799     return;
12800   const Expr *Base = ME->getBase();
12801   const CXXRecordDecl *MostDerivedClassDecl = Base->getBestDynamicClassType();
12802   if (!MostDerivedClassDecl)
12803     return;
12804   CXXMethodDecl *DM = MD->getCorrespondingMethodInClass(MostDerivedClassDecl);
12805   if (!DM || DM->isPure())
12806     return;
12807   SemaRef.MarkAnyDeclReferenced(Loc, DM, OdrUse);
12808 }
12809 
12810 /// \brief Perform reference-marking and odr-use handling for a DeclRefExpr.
MarkDeclRefReferenced(DeclRefExpr * E)12811 void Sema::MarkDeclRefReferenced(DeclRefExpr *E) {
12812   // TODO: update this with DR# once a defect report is filed.
12813   // C++11 defect. The address of a pure member should not be an ODR use, even
12814   // if it's a qualified reference.
12815   bool OdrUse = true;
12816   if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(E->getDecl()))
12817     if (Method->isVirtual())
12818       OdrUse = false;
12819   MarkExprReferenced(*this, E->getLocation(), E->getDecl(), E, OdrUse);
12820 }
12821 
12822 /// \brief Perform reference-marking and odr-use handling for a MemberExpr.
MarkMemberReferenced(MemberExpr * E)12823 void Sema::MarkMemberReferenced(MemberExpr *E) {
12824   // C++11 [basic.def.odr]p2:
12825   //   A non-overloaded function whose name appears as a potentially-evaluated
12826   //   expression or a member of a set of candidate functions, if selected by
12827   //   overload resolution when referred to from a potentially-evaluated
12828   //   expression, is odr-used, unless it is a pure virtual function and its
12829   //   name is not explicitly qualified.
12830   bool OdrUse = true;
12831   if (!E->hasQualifier()) {
12832     if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(E->getMemberDecl()))
12833       if (Method->isPure())
12834         OdrUse = false;
12835   }
12836   SourceLocation Loc = E->getMemberLoc().isValid() ?
12837                             E->getMemberLoc() : E->getLocStart();
12838   MarkExprReferenced(*this, Loc, E->getMemberDecl(), E, OdrUse);
12839 }
12840 
12841 /// \brief Perform marking for a reference to an arbitrary declaration.  It
12842 /// marks the declaration referenced, and performs odr-use checking for
12843 /// functions and variables. This method should not be used when building a
12844 /// normal expression which refers to a variable.
MarkAnyDeclReferenced(SourceLocation Loc,Decl * D,bool OdrUse)12845 void Sema::MarkAnyDeclReferenced(SourceLocation Loc, Decl *D, bool OdrUse) {
12846   if (OdrUse) {
12847     if (auto *VD = dyn_cast<VarDecl>(D)) {
12848       MarkVariableReferenced(Loc, VD);
12849       return;
12850     }
12851   }
12852   if (auto *FD = dyn_cast<FunctionDecl>(D)) {
12853     MarkFunctionReferenced(Loc, FD, OdrUse);
12854     return;
12855   }
12856   D->setReferenced();
12857 }
12858 
12859 namespace {
12860   // Mark all of the declarations referenced
12861   // FIXME: Not fully implemented yet! We need to have a better understanding
12862   // of when we're entering
12863   class MarkReferencedDecls : public RecursiveASTVisitor<MarkReferencedDecls> {
12864     Sema &S;
12865     SourceLocation Loc;
12866 
12867   public:
12868     typedef RecursiveASTVisitor<MarkReferencedDecls> Inherited;
12869 
MarkReferencedDecls(Sema & S,SourceLocation Loc)12870     MarkReferencedDecls(Sema &S, SourceLocation Loc) : S(S), Loc(Loc) { }
12871 
12872     bool TraverseTemplateArgument(const TemplateArgument &Arg);
12873     bool TraverseRecordType(RecordType *T);
12874   };
12875 }
12876 
TraverseTemplateArgument(const TemplateArgument & Arg)12877 bool MarkReferencedDecls::TraverseTemplateArgument(
12878     const TemplateArgument &Arg) {
12879   if (Arg.getKind() == TemplateArgument::Declaration) {
12880     if (Decl *D = Arg.getAsDecl())
12881       S.MarkAnyDeclReferenced(Loc, D, true);
12882   }
12883 
12884   return Inherited::TraverseTemplateArgument(Arg);
12885 }
12886 
TraverseRecordType(RecordType * T)12887 bool MarkReferencedDecls::TraverseRecordType(RecordType *T) {
12888   if (ClassTemplateSpecializationDecl *Spec
12889                   = dyn_cast<ClassTemplateSpecializationDecl>(T->getDecl())) {
12890     const TemplateArgumentList &Args = Spec->getTemplateArgs();
12891     return TraverseTemplateArguments(Args.data(), Args.size());
12892   }
12893 
12894   return true;
12895 }
12896 
MarkDeclarationsReferencedInType(SourceLocation Loc,QualType T)12897 void Sema::MarkDeclarationsReferencedInType(SourceLocation Loc, QualType T) {
12898   MarkReferencedDecls Marker(*this, Loc);
12899   Marker.TraverseType(Context.getCanonicalType(T));
12900 }
12901 
12902 namespace {
12903   /// \brief Helper class that marks all of the declarations referenced by
12904   /// potentially-evaluated subexpressions as "referenced".
12905   class EvaluatedExprMarker : public EvaluatedExprVisitor<EvaluatedExprMarker> {
12906     Sema &S;
12907     bool SkipLocalVariables;
12908 
12909   public:
12910     typedef EvaluatedExprVisitor<EvaluatedExprMarker> Inherited;
12911 
EvaluatedExprMarker(Sema & S,bool SkipLocalVariables)12912     EvaluatedExprMarker(Sema &S, bool SkipLocalVariables)
12913       : Inherited(S.Context), S(S), SkipLocalVariables(SkipLocalVariables) { }
12914 
VisitDeclRefExpr(DeclRefExpr * E)12915     void VisitDeclRefExpr(DeclRefExpr *E) {
12916       // If we were asked not to visit local variables, don't.
12917       if (SkipLocalVariables) {
12918         if (VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()))
12919           if (VD->hasLocalStorage())
12920             return;
12921       }
12922 
12923       S.MarkDeclRefReferenced(E);
12924     }
12925 
VisitMemberExpr(MemberExpr * E)12926     void VisitMemberExpr(MemberExpr *E) {
12927       S.MarkMemberReferenced(E);
12928       Inherited::VisitMemberExpr(E);
12929     }
12930 
VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr * E)12931     void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
12932       S.MarkFunctionReferenced(E->getLocStart(),
12933             const_cast<CXXDestructorDecl*>(E->getTemporary()->getDestructor()));
12934       Visit(E->getSubExpr());
12935     }
12936 
VisitCXXNewExpr(CXXNewExpr * E)12937     void VisitCXXNewExpr(CXXNewExpr *E) {
12938       if (E->getOperatorNew())
12939         S.MarkFunctionReferenced(E->getLocStart(), E->getOperatorNew());
12940       if (E->getOperatorDelete())
12941         S.MarkFunctionReferenced(E->getLocStart(), E->getOperatorDelete());
12942       Inherited::VisitCXXNewExpr(E);
12943     }
12944 
VisitCXXDeleteExpr(CXXDeleteExpr * E)12945     void VisitCXXDeleteExpr(CXXDeleteExpr *E) {
12946       if (E->getOperatorDelete())
12947         S.MarkFunctionReferenced(E->getLocStart(), E->getOperatorDelete());
12948       QualType Destroyed = S.Context.getBaseElementType(E->getDestroyedType());
12949       if (const RecordType *DestroyedRec = Destroyed->getAs<RecordType>()) {
12950         CXXRecordDecl *Record = cast<CXXRecordDecl>(DestroyedRec->getDecl());
12951         S.MarkFunctionReferenced(E->getLocStart(),
12952                                     S.LookupDestructor(Record));
12953       }
12954 
12955       Inherited::VisitCXXDeleteExpr(E);
12956     }
12957 
VisitCXXConstructExpr(CXXConstructExpr * E)12958     void VisitCXXConstructExpr(CXXConstructExpr *E) {
12959       S.MarkFunctionReferenced(E->getLocStart(), E->getConstructor());
12960       Inherited::VisitCXXConstructExpr(E);
12961     }
12962 
VisitCXXDefaultArgExpr(CXXDefaultArgExpr * E)12963     void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *E) {
12964       Visit(E->getExpr());
12965     }
12966 
VisitImplicitCastExpr(ImplicitCastExpr * E)12967     void VisitImplicitCastExpr(ImplicitCastExpr *E) {
12968       Inherited::VisitImplicitCastExpr(E);
12969 
12970       if (E->getCastKind() == CK_LValueToRValue)
12971         S.UpdateMarkingForLValueToRValue(E->getSubExpr());
12972     }
12973   };
12974 }
12975 
12976 /// \brief Mark any declarations that appear within this expression or any
12977 /// potentially-evaluated subexpressions as "referenced".
12978 ///
12979 /// \param SkipLocalVariables If true, don't mark local variables as
12980 /// 'referenced'.
MarkDeclarationsReferencedInExpr(Expr * E,bool SkipLocalVariables)12981 void Sema::MarkDeclarationsReferencedInExpr(Expr *E,
12982                                             bool SkipLocalVariables) {
12983   EvaluatedExprMarker(*this, SkipLocalVariables).Visit(E);
12984 }
12985 
12986 /// \brief Emit a diagnostic that describes an effect on the run-time behavior
12987 /// of the program being compiled.
12988 ///
12989 /// This routine emits the given diagnostic when the code currently being
12990 /// type-checked is "potentially evaluated", meaning that there is a
12991 /// possibility that the code will actually be executable. Code in sizeof()
12992 /// expressions, code used only during overload resolution, etc., are not
12993 /// potentially evaluated. This routine will suppress such diagnostics or,
12994 /// in the absolutely nutty case of potentially potentially evaluated
12995 /// expressions (C++ typeid), queue the diagnostic to potentially emit it
12996 /// later.
12997 ///
12998 /// This routine should be used for all diagnostics that describe the run-time
12999 /// behavior of a program, such as passing a non-POD value through an ellipsis.
13000 /// Failure to do so will likely result in spurious diagnostics or failures
13001 /// during overload resolution or within sizeof/alignof/typeof/typeid.
DiagRuntimeBehavior(SourceLocation Loc,const Stmt * Statement,const PartialDiagnostic & PD)13002 bool Sema::DiagRuntimeBehavior(SourceLocation Loc, const Stmt *Statement,
13003                                const PartialDiagnostic &PD) {
13004   switch (ExprEvalContexts.back().Context) {
13005   case Unevaluated:
13006   case UnevaluatedAbstract:
13007     // The argument will never be evaluated, so don't complain.
13008     break;
13009 
13010   case ConstantEvaluated:
13011     // Relevant diagnostics should be produced by constant evaluation.
13012     break;
13013 
13014   case PotentiallyEvaluated:
13015   case PotentiallyEvaluatedIfUsed:
13016     if (Statement && getCurFunctionOrMethodDecl()) {
13017       FunctionScopes.back()->PossiblyUnreachableDiags.
13018         push_back(sema::PossiblyUnreachableDiag(PD, Loc, Statement));
13019     }
13020     else
13021       Diag(Loc, PD);
13022 
13023     return true;
13024   }
13025 
13026   return false;
13027 }
13028 
CheckCallReturnType(QualType ReturnType,SourceLocation Loc,CallExpr * CE,FunctionDecl * FD)13029 bool Sema::CheckCallReturnType(QualType ReturnType, SourceLocation Loc,
13030                                CallExpr *CE, FunctionDecl *FD) {
13031   if (ReturnType->isVoidType() || !ReturnType->isIncompleteType())
13032     return false;
13033 
13034   // If we're inside a decltype's expression, don't check for a valid return
13035   // type or construct temporaries until we know whether this is the last call.
13036   if (ExprEvalContexts.back().IsDecltype) {
13037     ExprEvalContexts.back().DelayedDecltypeCalls.push_back(CE);
13038     return false;
13039   }
13040 
13041   class CallReturnIncompleteDiagnoser : public TypeDiagnoser {
13042     FunctionDecl *FD;
13043     CallExpr *CE;
13044 
13045   public:
13046     CallReturnIncompleteDiagnoser(FunctionDecl *FD, CallExpr *CE)
13047       : FD(FD), CE(CE) { }
13048 
13049     void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
13050       if (!FD) {
13051         S.Diag(Loc, diag::err_call_incomplete_return)
13052           << T << CE->getSourceRange();
13053         return;
13054       }
13055 
13056       S.Diag(Loc, diag::err_call_function_incomplete_return)
13057         << CE->getSourceRange() << FD->getDeclName() << T;
13058       S.Diag(FD->getLocation(), diag::note_entity_declared_at)
13059           << FD->getDeclName();
13060     }
13061   } Diagnoser(FD, CE);
13062 
13063   if (RequireCompleteType(Loc, ReturnType, Diagnoser))
13064     return true;
13065 
13066   return false;
13067 }
13068 
13069 // Diagnose the s/=/==/ and s/\|=/!=/ typos. Note that adding parentheses
13070 // will prevent this condition from triggering, which is what we want.
DiagnoseAssignmentAsCondition(Expr * E)13071 void Sema::DiagnoseAssignmentAsCondition(Expr *E) {
13072   SourceLocation Loc;
13073 
13074   unsigned diagnostic = diag::warn_condition_is_assignment;
13075   bool IsOrAssign = false;
13076 
13077   if (BinaryOperator *Op = dyn_cast<BinaryOperator>(E)) {
13078     if (Op->getOpcode() != BO_Assign && Op->getOpcode() != BO_OrAssign)
13079       return;
13080 
13081     IsOrAssign = Op->getOpcode() == BO_OrAssign;
13082 
13083     // Greylist some idioms by putting them into a warning subcategory.
13084     if (ObjCMessageExpr *ME
13085           = dyn_cast<ObjCMessageExpr>(Op->getRHS()->IgnoreParenCasts())) {
13086       Selector Sel = ME->getSelector();
13087 
13088       // self = [<foo> init...]
13089       if (isSelfExpr(Op->getLHS()) && ME->getMethodFamily() == OMF_init)
13090         diagnostic = diag::warn_condition_is_idiomatic_assignment;
13091 
13092       // <foo> = [<bar> nextObject]
13093       else if (Sel.isUnarySelector() && Sel.getNameForSlot(0) == "nextObject")
13094         diagnostic = diag::warn_condition_is_idiomatic_assignment;
13095     }
13096 
13097     Loc = Op->getOperatorLoc();
13098   } else if (CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(E)) {
13099     if (Op->getOperator() != OO_Equal && Op->getOperator() != OO_PipeEqual)
13100       return;
13101 
13102     IsOrAssign = Op->getOperator() == OO_PipeEqual;
13103     Loc = Op->getOperatorLoc();
13104   } else if (PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E))
13105     return DiagnoseAssignmentAsCondition(POE->getSyntacticForm());
13106   else {
13107     // Not an assignment.
13108     return;
13109   }
13110 
13111   Diag(Loc, diagnostic) << E->getSourceRange();
13112 
13113   SourceLocation Open = E->getLocStart();
13114   SourceLocation Close = PP.getLocForEndOfToken(E->getSourceRange().getEnd());
13115   Diag(Loc, diag::note_condition_assign_silence)
13116         << FixItHint::CreateInsertion(Open, "(")
13117         << FixItHint::CreateInsertion(Close, ")");
13118 
13119   if (IsOrAssign)
13120     Diag(Loc, diag::note_condition_or_assign_to_comparison)
13121       << FixItHint::CreateReplacement(Loc, "!=");
13122   else
13123     Diag(Loc, diag::note_condition_assign_to_comparison)
13124       << FixItHint::CreateReplacement(Loc, "==");
13125 }
13126 
13127 /// \brief Redundant parentheses over an equality comparison can indicate
13128 /// that the user intended an assignment used as condition.
DiagnoseEqualityWithExtraParens(ParenExpr * ParenE)13129 void Sema::DiagnoseEqualityWithExtraParens(ParenExpr *ParenE) {
13130   // Don't warn if the parens came from a macro.
13131   SourceLocation parenLoc = ParenE->getLocStart();
13132   if (parenLoc.isInvalid() || parenLoc.isMacroID())
13133     return;
13134   // Don't warn for dependent expressions.
13135   if (ParenE->isTypeDependent())
13136     return;
13137 
13138   Expr *E = ParenE->IgnoreParens();
13139 
13140   if (BinaryOperator *opE = dyn_cast<BinaryOperator>(E))
13141     if (opE->getOpcode() == BO_EQ &&
13142         opE->getLHS()->IgnoreParenImpCasts()->isModifiableLvalue(Context)
13143                                                            == Expr::MLV_Valid) {
13144       SourceLocation Loc = opE->getOperatorLoc();
13145 
13146       Diag(Loc, diag::warn_equality_with_extra_parens) << E->getSourceRange();
13147       SourceRange ParenERange = ParenE->getSourceRange();
13148       Diag(Loc, diag::note_equality_comparison_silence)
13149         << FixItHint::CreateRemoval(ParenERange.getBegin())
13150         << FixItHint::CreateRemoval(ParenERange.getEnd());
13151       Diag(Loc, diag::note_equality_comparison_to_assign)
13152         << FixItHint::CreateReplacement(Loc, "=");
13153     }
13154 }
13155 
CheckBooleanCondition(Expr * E,SourceLocation Loc)13156 ExprResult Sema::CheckBooleanCondition(Expr *E, SourceLocation Loc) {
13157   DiagnoseAssignmentAsCondition(E);
13158   if (ParenExpr *parenE = dyn_cast<ParenExpr>(E))
13159     DiagnoseEqualityWithExtraParens(parenE);
13160 
13161   ExprResult result = CheckPlaceholderExpr(E);
13162   if (result.isInvalid()) return ExprError();
13163   E = result.get();
13164 
13165   if (!E->isTypeDependent()) {
13166     if (getLangOpts().CPlusPlus)
13167       return CheckCXXBooleanCondition(E); // C++ 6.4p4
13168 
13169     ExprResult ERes = DefaultFunctionArrayLvalueConversion(E);
13170     if (ERes.isInvalid())
13171       return ExprError();
13172     E = ERes.get();
13173 
13174     QualType T = E->getType();
13175     if (!T->isScalarType()) { // C99 6.8.4.1p1
13176       Diag(Loc, diag::err_typecheck_statement_requires_scalar)
13177         << T << E->getSourceRange();
13178       return ExprError();
13179     }
13180     CheckBoolLikeConversion(E, Loc);
13181   }
13182 
13183   return E;
13184 }
13185 
ActOnBooleanCondition(Scope * S,SourceLocation Loc,Expr * SubExpr)13186 ExprResult Sema::ActOnBooleanCondition(Scope *S, SourceLocation Loc,
13187                                        Expr *SubExpr) {
13188   if (!SubExpr)
13189     return ExprError();
13190 
13191   return CheckBooleanCondition(SubExpr, Loc);
13192 }
13193 
13194 namespace {
13195   /// A visitor for rebuilding a call to an __unknown_any expression
13196   /// to have an appropriate type.
13197   struct RebuildUnknownAnyFunction
13198     : StmtVisitor<RebuildUnknownAnyFunction, ExprResult> {
13199 
13200     Sema &S;
13201 
RebuildUnknownAnyFunction__anon57bc949f0a11::RebuildUnknownAnyFunction13202     RebuildUnknownAnyFunction(Sema &S) : S(S) {}
13203 
VisitStmt__anon57bc949f0a11::RebuildUnknownAnyFunction13204     ExprResult VisitStmt(Stmt *S) {
13205       llvm_unreachable("unexpected statement!");
13206     }
13207 
VisitExpr__anon57bc949f0a11::RebuildUnknownAnyFunction13208     ExprResult VisitExpr(Expr *E) {
13209       S.Diag(E->getExprLoc(), diag::err_unsupported_unknown_any_call)
13210         << E->getSourceRange();
13211       return ExprError();
13212     }
13213 
13214     /// Rebuild an expression which simply semantically wraps another
13215     /// expression which it shares the type and value kind of.
rebuildSugarExpr__anon57bc949f0a11::RebuildUnknownAnyFunction13216     template <class T> ExprResult rebuildSugarExpr(T *E) {
13217       ExprResult SubResult = Visit(E->getSubExpr());
13218       if (SubResult.isInvalid()) return ExprError();
13219 
13220       Expr *SubExpr = SubResult.get();
13221       E->setSubExpr(SubExpr);
13222       E->setType(SubExpr->getType());
13223       E->setValueKind(SubExpr->getValueKind());
13224       assert(E->getObjectKind() == OK_Ordinary);
13225       return E;
13226     }
13227 
VisitParenExpr__anon57bc949f0a11::RebuildUnknownAnyFunction13228     ExprResult VisitParenExpr(ParenExpr *E) {
13229       return rebuildSugarExpr(E);
13230     }
13231 
VisitUnaryExtension__anon57bc949f0a11::RebuildUnknownAnyFunction13232     ExprResult VisitUnaryExtension(UnaryOperator *E) {
13233       return rebuildSugarExpr(E);
13234     }
13235 
VisitUnaryAddrOf__anon57bc949f0a11::RebuildUnknownAnyFunction13236     ExprResult VisitUnaryAddrOf(UnaryOperator *E) {
13237       ExprResult SubResult = Visit(E->getSubExpr());
13238       if (SubResult.isInvalid()) return ExprError();
13239 
13240       Expr *SubExpr = SubResult.get();
13241       E->setSubExpr(SubExpr);
13242       E->setType(S.Context.getPointerType(SubExpr->getType()));
13243       assert(E->getValueKind() == VK_RValue);
13244       assert(E->getObjectKind() == OK_Ordinary);
13245       return E;
13246     }
13247 
resolveDecl__anon57bc949f0a11::RebuildUnknownAnyFunction13248     ExprResult resolveDecl(Expr *E, ValueDecl *VD) {
13249       if (!isa<FunctionDecl>(VD)) return VisitExpr(E);
13250 
13251       E->setType(VD->getType());
13252 
13253       assert(E->getValueKind() == VK_RValue);
13254       if (S.getLangOpts().CPlusPlus &&
13255           !(isa<CXXMethodDecl>(VD) &&
13256             cast<CXXMethodDecl>(VD)->isInstance()))
13257         E->setValueKind(VK_LValue);
13258 
13259       return E;
13260     }
13261 
VisitMemberExpr__anon57bc949f0a11::RebuildUnknownAnyFunction13262     ExprResult VisitMemberExpr(MemberExpr *E) {
13263       return resolveDecl(E, E->getMemberDecl());
13264     }
13265 
VisitDeclRefExpr__anon57bc949f0a11::RebuildUnknownAnyFunction13266     ExprResult VisitDeclRefExpr(DeclRefExpr *E) {
13267       return resolveDecl(E, E->getDecl());
13268     }
13269   };
13270 }
13271 
13272 /// Given a function expression of unknown-any type, try to rebuild it
13273 /// to have a function type.
rebuildUnknownAnyFunction(Sema & S,Expr * FunctionExpr)13274 static ExprResult rebuildUnknownAnyFunction(Sema &S, Expr *FunctionExpr) {
13275   ExprResult Result = RebuildUnknownAnyFunction(S).Visit(FunctionExpr);
13276   if (Result.isInvalid()) return ExprError();
13277   return S.DefaultFunctionArrayConversion(Result.get());
13278 }
13279 
13280 namespace {
13281   /// A visitor for rebuilding an expression of type __unknown_anytype
13282   /// into one which resolves the type directly on the referring
13283   /// expression.  Strict preservation of the original source
13284   /// structure is not a goal.
13285   struct RebuildUnknownAnyExpr
13286     : StmtVisitor<RebuildUnknownAnyExpr, ExprResult> {
13287 
13288     Sema &S;
13289 
13290     /// The current destination type.
13291     QualType DestType;
13292 
RebuildUnknownAnyExpr__anon57bc949f0b11::RebuildUnknownAnyExpr13293     RebuildUnknownAnyExpr(Sema &S, QualType CastType)
13294       : S(S), DestType(CastType) {}
13295 
VisitStmt__anon57bc949f0b11::RebuildUnknownAnyExpr13296     ExprResult VisitStmt(Stmt *S) {
13297       llvm_unreachable("unexpected statement!");
13298     }
13299 
VisitExpr__anon57bc949f0b11::RebuildUnknownAnyExpr13300     ExprResult VisitExpr(Expr *E) {
13301       S.Diag(E->getExprLoc(), diag::err_unsupported_unknown_any_expr)
13302         << E->getSourceRange();
13303       return ExprError();
13304     }
13305 
13306     ExprResult VisitCallExpr(CallExpr *E);
13307     ExprResult VisitObjCMessageExpr(ObjCMessageExpr *E);
13308 
13309     /// Rebuild an expression which simply semantically wraps another
13310     /// expression which it shares the type and value kind of.
rebuildSugarExpr__anon57bc949f0b11::RebuildUnknownAnyExpr13311     template <class T> ExprResult rebuildSugarExpr(T *E) {
13312       ExprResult SubResult = Visit(E->getSubExpr());
13313       if (SubResult.isInvalid()) return ExprError();
13314       Expr *SubExpr = SubResult.get();
13315       E->setSubExpr(SubExpr);
13316       E->setType(SubExpr->getType());
13317       E->setValueKind(SubExpr->getValueKind());
13318       assert(E->getObjectKind() == OK_Ordinary);
13319       return E;
13320     }
13321 
VisitParenExpr__anon57bc949f0b11::RebuildUnknownAnyExpr13322     ExprResult VisitParenExpr(ParenExpr *E) {
13323       return rebuildSugarExpr(E);
13324     }
13325 
VisitUnaryExtension__anon57bc949f0b11::RebuildUnknownAnyExpr13326     ExprResult VisitUnaryExtension(UnaryOperator *E) {
13327       return rebuildSugarExpr(E);
13328     }
13329 
VisitUnaryAddrOf__anon57bc949f0b11::RebuildUnknownAnyExpr13330     ExprResult VisitUnaryAddrOf(UnaryOperator *E) {
13331       const PointerType *Ptr = DestType->getAs<PointerType>();
13332       if (!Ptr) {
13333         S.Diag(E->getOperatorLoc(), diag::err_unknown_any_addrof)
13334           << E->getSourceRange();
13335         return ExprError();
13336       }
13337       assert(E->getValueKind() == VK_RValue);
13338       assert(E->getObjectKind() == OK_Ordinary);
13339       E->setType(DestType);
13340 
13341       // Build the sub-expression as if it were an object of the pointee type.
13342       DestType = Ptr->getPointeeType();
13343       ExprResult SubResult = Visit(E->getSubExpr());
13344       if (SubResult.isInvalid()) return ExprError();
13345       E->setSubExpr(SubResult.get());
13346       return E;
13347     }
13348 
13349     ExprResult VisitImplicitCastExpr(ImplicitCastExpr *E);
13350 
13351     ExprResult resolveDecl(Expr *E, ValueDecl *VD);
13352 
VisitMemberExpr__anon57bc949f0b11::RebuildUnknownAnyExpr13353     ExprResult VisitMemberExpr(MemberExpr *E) {
13354       return resolveDecl(E, E->getMemberDecl());
13355     }
13356 
VisitDeclRefExpr__anon57bc949f0b11::RebuildUnknownAnyExpr13357     ExprResult VisitDeclRefExpr(DeclRefExpr *E) {
13358       return resolveDecl(E, E->getDecl());
13359     }
13360   };
13361 }
13362 
13363 /// Rebuilds a call expression which yielded __unknown_anytype.
VisitCallExpr(CallExpr * E)13364 ExprResult RebuildUnknownAnyExpr::VisitCallExpr(CallExpr *E) {
13365   Expr *CalleeExpr = E->getCallee();
13366 
13367   enum FnKind {
13368     FK_MemberFunction,
13369     FK_FunctionPointer,
13370     FK_BlockPointer
13371   };
13372 
13373   FnKind Kind;
13374   QualType CalleeType = CalleeExpr->getType();
13375   if (CalleeType == S.Context.BoundMemberTy) {
13376     assert(isa<CXXMemberCallExpr>(E) || isa<CXXOperatorCallExpr>(E));
13377     Kind = FK_MemberFunction;
13378     CalleeType = Expr::findBoundMemberType(CalleeExpr);
13379   } else if (const PointerType *Ptr = CalleeType->getAs<PointerType>()) {
13380     CalleeType = Ptr->getPointeeType();
13381     Kind = FK_FunctionPointer;
13382   } else {
13383     CalleeType = CalleeType->castAs<BlockPointerType>()->getPointeeType();
13384     Kind = FK_BlockPointer;
13385   }
13386   const FunctionType *FnType = CalleeType->castAs<FunctionType>();
13387 
13388   // Verify that this is a legal result type of a function.
13389   if (DestType->isArrayType() || DestType->isFunctionType()) {
13390     unsigned diagID = diag::err_func_returning_array_function;
13391     if (Kind == FK_BlockPointer)
13392       diagID = diag::err_block_returning_array_function;
13393 
13394     S.Diag(E->getExprLoc(), diagID)
13395       << DestType->isFunctionType() << DestType;
13396     return ExprError();
13397   }
13398 
13399   // Otherwise, go ahead and set DestType as the call's result.
13400   E->setType(DestType.getNonLValueExprType(S.Context));
13401   E->setValueKind(Expr::getValueKindForType(DestType));
13402   assert(E->getObjectKind() == OK_Ordinary);
13403 
13404   // Rebuild the function type, replacing the result type with DestType.
13405   const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FnType);
13406   if (Proto) {
13407     // __unknown_anytype(...) is a special case used by the debugger when
13408     // it has no idea what a function's signature is.
13409     //
13410     // We want to build this call essentially under the K&R
13411     // unprototyped rules, but making a FunctionNoProtoType in C++
13412     // would foul up all sorts of assumptions.  However, we cannot
13413     // simply pass all arguments as variadic arguments, nor can we
13414     // portably just call the function under a non-variadic type; see
13415     // the comment on IR-gen's TargetInfo::isNoProtoCallVariadic.
13416     // However, it turns out that in practice it is generally safe to
13417     // call a function declared as "A foo(B,C,D);" under the prototype
13418     // "A foo(B,C,D,...);".  The only known exception is with the
13419     // Windows ABI, where any variadic function is implicitly cdecl
13420     // regardless of its normal CC.  Therefore we change the parameter
13421     // types to match the types of the arguments.
13422     //
13423     // This is a hack, but it is far superior to moving the
13424     // corresponding target-specific code from IR-gen to Sema/AST.
13425 
13426     ArrayRef<QualType> ParamTypes = Proto->getParamTypes();
13427     SmallVector<QualType, 8> ArgTypes;
13428     if (ParamTypes.empty() && Proto->isVariadic()) { // the special case
13429       ArgTypes.reserve(E->getNumArgs());
13430       for (unsigned i = 0, e = E->getNumArgs(); i != e; ++i) {
13431         Expr *Arg = E->getArg(i);
13432         QualType ArgType = Arg->getType();
13433         if (E->isLValue()) {
13434           ArgType = S.Context.getLValueReferenceType(ArgType);
13435         } else if (E->isXValue()) {
13436           ArgType = S.Context.getRValueReferenceType(ArgType);
13437         }
13438         ArgTypes.push_back(ArgType);
13439       }
13440       ParamTypes = ArgTypes;
13441     }
13442     DestType = S.Context.getFunctionType(DestType, ParamTypes,
13443                                          Proto->getExtProtoInfo());
13444   } else {
13445     DestType = S.Context.getFunctionNoProtoType(DestType,
13446                                                 FnType->getExtInfo());
13447   }
13448 
13449   // Rebuild the appropriate pointer-to-function type.
13450   switch (Kind) {
13451   case FK_MemberFunction:
13452     // Nothing to do.
13453     break;
13454 
13455   case FK_FunctionPointer:
13456     DestType = S.Context.getPointerType(DestType);
13457     break;
13458 
13459   case FK_BlockPointer:
13460     DestType = S.Context.getBlockPointerType(DestType);
13461     break;
13462   }
13463 
13464   // Finally, we can recurse.
13465   ExprResult CalleeResult = Visit(CalleeExpr);
13466   if (!CalleeResult.isUsable()) return ExprError();
13467   E->setCallee(CalleeResult.get());
13468 
13469   // Bind a temporary if necessary.
13470   return S.MaybeBindToTemporary(E);
13471 }
13472 
VisitObjCMessageExpr(ObjCMessageExpr * E)13473 ExprResult RebuildUnknownAnyExpr::VisitObjCMessageExpr(ObjCMessageExpr *E) {
13474   // Verify that this is a legal result type of a call.
13475   if (DestType->isArrayType() || DestType->isFunctionType()) {
13476     S.Diag(E->getExprLoc(), diag::err_func_returning_array_function)
13477       << DestType->isFunctionType() << DestType;
13478     return ExprError();
13479   }
13480 
13481   // Rewrite the method result type if available.
13482   if (ObjCMethodDecl *Method = E->getMethodDecl()) {
13483     assert(Method->getReturnType() == S.Context.UnknownAnyTy);
13484     Method->setReturnType(DestType);
13485   }
13486 
13487   // Change the type of the message.
13488   E->setType(DestType.getNonReferenceType());
13489   E->setValueKind(Expr::getValueKindForType(DestType));
13490 
13491   return S.MaybeBindToTemporary(E);
13492 }
13493 
VisitImplicitCastExpr(ImplicitCastExpr * E)13494 ExprResult RebuildUnknownAnyExpr::VisitImplicitCastExpr(ImplicitCastExpr *E) {
13495   // The only case we should ever see here is a function-to-pointer decay.
13496   if (E->getCastKind() == CK_FunctionToPointerDecay) {
13497     assert(E->getValueKind() == VK_RValue);
13498     assert(E->getObjectKind() == OK_Ordinary);
13499 
13500     E->setType(DestType);
13501 
13502     // Rebuild the sub-expression as the pointee (function) type.
13503     DestType = DestType->castAs<PointerType>()->getPointeeType();
13504 
13505     ExprResult Result = Visit(E->getSubExpr());
13506     if (!Result.isUsable()) return ExprError();
13507 
13508     E->setSubExpr(Result.get());
13509     return E;
13510   } else if (E->getCastKind() == CK_LValueToRValue) {
13511     assert(E->getValueKind() == VK_RValue);
13512     assert(E->getObjectKind() == OK_Ordinary);
13513 
13514     assert(isa<BlockPointerType>(E->getType()));
13515 
13516     E->setType(DestType);
13517 
13518     // The sub-expression has to be a lvalue reference, so rebuild it as such.
13519     DestType = S.Context.getLValueReferenceType(DestType);
13520 
13521     ExprResult Result = Visit(E->getSubExpr());
13522     if (!Result.isUsable()) return ExprError();
13523 
13524     E->setSubExpr(Result.get());
13525     return E;
13526   } else {
13527     llvm_unreachable("Unhandled cast type!");
13528   }
13529 }
13530 
resolveDecl(Expr * E,ValueDecl * VD)13531 ExprResult RebuildUnknownAnyExpr::resolveDecl(Expr *E, ValueDecl *VD) {
13532   ExprValueKind ValueKind = VK_LValue;
13533   QualType Type = DestType;
13534 
13535   // We know how to make this work for certain kinds of decls:
13536 
13537   //  - functions
13538   if (FunctionDecl *FD = dyn_cast<FunctionDecl>(VD)) {
13539     if (const PointerType *Ptr = Type->getAs<PointerType>()) {
13540       DestType = Ptr->getPointeeType();
13541       ExprResult Result = resolveDecl(E, VD);
13542       if (Result.isInvalid()) return ExprError();
13543       return S.ImpCastExprToType(Result.get(), Type,
13544                                  CK_FunctionToPointerDecay, VK_RValue);
13545     }
13546 
13547     if (!Type->isFunctionType()) {
13548       S.Diag(E->getExprLoc(), diag::err_unknown_any_function)
13549         << VD << E->getSourceRange();
13550       return ExprError();
13551     }
13552     if (const FunctionProtoType *FT = Type->getAs<FunctionProtoType>()) {
13553       // We must match the FunctionDecl's type to the hack introduced in
13554       // RebuildUnknownAnyExpr::VisitCallExpr to vararg functions of unknown
13555       // type. See the lengthy commentary in that routine.
13556       QualType FDT = FD->getType();
13557       const FunctionType *FnType = FDT->castAs<FunctionType>();
13558       const FunctionProtoType *Proto = dyn_cast_or_null<FunctionProtoType>(FnType);
13559       DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E);
13560       if (DRE && Proto && Proto->getParamTypes().empty() && Proto->isVariadic()) {
13561         SourceLocation Loc = FD->getLocation();
13562         FunctionDecl *NewFD = FunctionDecl::Create(FD->getASTContext(),
13563                                       FD->getDeclContext(),
13564                                       Loc, Loc, FD->getNameInfo().getName(),
13565                                       DestType, FD->getTypeSourceInfo(),
13566                                       SC_None, false/*isInlineSpecified*/,
13567                                       FD->hasPrototype(),
13568                                       false/*isConstexprSpecified*/);
13569 
13570         if (FD->getQualifier())
13571           NewFD->setQualifierInfo(FD->getQualifierLoc());
13572 
13573         SmallVector<ParmVarDecl*, 16> Params;
13574         for (const auto &AI : FT->param_types()) {
13575           ParmVarDecl *Param =
13576             S.BuildParmVarDeclForTypedef(FD, Loc, AI);
13577           Param->setScopeInfo(0, Params.size());
13578           Params.push_back(Param);
13579         }
13580         NewFD->setParams(Params);
13581         DRE->setDecl(NewFD);
13582         VD = DRE->getDecl();
13583       }
13584     }
13585 
13586     if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD))
13587       if (MD->isInstance()) {
13588         ValueKind = VK_RValue;
13589         Type = S.Context.BoundMemberTy;
13590       }
13591 
13592     // Function references aren't l-values in C.
13593     if (!S.getLangOpts().CPlusPlus)
13594       ValueKind = VK_RValue;
13595 
13596   //  - variables
13597   } else if (isa<VarDecl>(VD)) {
13598     if (const ReferenceType *RefTy = Type->getAs<ReferenceType>()) {
13599       Type = RefTy->getPointeeType();
13600     } else if (Type->isFunctionType()) {
13601       S.Diag(E->getExprLoc(), diag::err_unknown_any_var_function_type)
13602         << VD << E->getSourceRange();
13603       return ExprError();
13604     }
13605 
13606   //  - nothing else
13607   } else {
13608     S.Diag(E->getExprLoc(), diag::err_unsupported_unknown_any_decl)
13609       << VD << E->getSourceRange();
13610     return ExprError();
13611   }
13612 
13613   // Modifying the declaration like this is friendly to IR-gen but
13614   // also really dangerous.
13615   VD->setType(DestType);
13616   E->setType(Type);
13617   E->setValueKind(ValueKind);
13618   return E;
13619 }
13620 
13621 /// Check a cast of an unknown-any type.  We intentionally only
13622 /// trigger this for C-style casts.
checkUnknownAnyCast(SourceRange TypeRange,QualType CastType,Expr * CastExpr,CastKind & CastKind,ExprValueKind & VK,CXXCastPath & Path)13623 ExprResult Sema::checkUnknownAnyCast(SourceRange TypeRange, QualType CastType,
13624                                      Expr *CastExpr, CastKind &CastKind,
13625                                      ExprValueKind &VK, CXXCastPath &Path) {
13626   // Rewrite the casted expression from scratch.
13627   ExprResult result = RebuildUnknownAnyExpr(*this, CastType).Visit(CastExpr);
13628   if (!result.isUsable()) return ExprError();
13629 
13630   CastExpr = result.get();
13631   VK = CastExpr->getValueKind();
13632   CastKind = CK_NoOp;
13633 
13634   return CastExpr;
13635 }
13636 
forceUnknownAnyToType(Expr * E,QualType ToType)13637 ExprResult Sema::forceUnknownAnyToType(Expr *E, QualType ToType) {
13638   return RebuildUnknownAnyExpr(*this, ToType).Visit(E);
13639 }
13640 
checkUnknownAnyArg(SourceLocation callLoc,Expr * arg,QualType & paramType)13641 ExprResult Sema::checkUnknownAnyArg(SourceLocation callLoc,
13642                                     Expr *arg, QualType &paramType) {
13643   // If the syntactic form of the argument is not an explicit cast of
13644   // any sort, just do default argument promotion.
13645   ExplicitCastExpr *castArg = dyn_cast<ExplicitCastExpr>(arg->IgnoreParens());
13646   if (!castArg) {
13647     ExprResult result = DefaultArgumentPromotion(arg);
13648     if (result.isInvalid()) return ExprError();
13649     paramType = result.get()->getType();
13650     return result;
13651   }
13652 
13653   // Otherwise, use the type that was written in the explicit cast.
13654   assert(!arg->hasPlaceholderType());
13655   paramType = castArg->getTypeAsWritten();
13656 
13657   // Copy-initialize a parameter of that type.
13658   InitializedEntity entity =
13659     InitializedEntity::InitializeParameter(Context, paramType,
13660                                            /*consumed*/ false);
13661   return PerformCopyInitialization(entity, callLoc, arg);
13662 }
13663 
diagnoseUnknownAnyExpr(Sema & S,Expr * E)13664 static ExprResult diagnoseUnknownAnyExpr(Sema &S, Expr *E) {
13665   Expr *orig = E;
13666   unsigned diagID = diag::err_uncasted_use_of_unknown_any;
13667   while (true) {
13668     E = E->IgnoreParenImpCasts();
13669     if (CallExpr *call = dyn_cast<CallExpr>(E)) {
13670       E = call->getCallee();
13671       diagID = diag::err_uncasted_call_of_unknown_any;
13672     } else {
13673       break;
13674     }
13675   }
13676 
13677   SourceLocation loc;
13678   NamedDecl *d;
13679   if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(E)) {
13680     loc = ref->getLocation();
13681     d = ref->getDecl();
13682   } else if (MemberExpr *mem = dyn_cast<MemberExpr>(E)) {
13683     loc = mem->getMemberLoc();
13684     d = mem->getMemberDecl();
13685   } else if (ObjCMessageExpr *msg = dyn_cast<ObjCMessageExpr>(E)) {
13686     diagID = diag::err_uncasted_call_of_unknown_any;
13687     loc = msg->getSelectorStartLoc();
13688     d = msg->getMethodDecl();
13689     if (!d) {
13690       S.Diag(loc, diag::err_uncasted_send_to_unknown_any_method)
13691         << static_cast<unsigned>(msg->isClassMessage()) << msg->getSelector()
13692         << orig->getSourceRange();
13693       return ExprError();
13694     }
13695   } else {
13696     S.Diag(E->getExprLoc(), diag::err_unsupported_unknown_any_expr)
13697       << E->getSourceRange();
13698     return ExprError();
13699   }
13700 
13701   S.Diag(loc, diagID) << d << orig->getSourceRange();
13702 
13703   // Never recoverable.
13704   return ExprError();
13705 }
13706 
13707 /// Check for operands with placeholder types and complain if found.
13708 /// Returns true if there was an error and no recovery was possible.
CheckPlaceholderExpr(Expr * E)13709 ExprResult Sema::CheckPlaceholderExpr(Expr *E) {
13710   if (!getLangOpts().CPlusPlus) {
13711     // C cannot handle TypoExpr nodes on either side of a binop because it
13712     // doesn't handle dependent types properly, so make sure any TypoExprs have
13713     // been dealt with before checking the operands.
13714     ExprResult Result = CorrectDelayedTyposInExpr(E);
13715     if (!Result.isUsable()) return ExprError();
13716     E = Result.get();
13717   }
13718 
13719   const BuiltinType *placeholderType = E->getType()->getAsPlaceholderType();
13720   if (!placeholderType) return E;
13721 
13722   switch (placeholderType->getKind()) {
13723 
13724   // Overloaded expressions.
13725   case BuiltinType::Overload: {
13726     // Try to resolve a single function template specialization.
13727     // This is obligatory.
13728     ExprResult result = E;
13729     if (ResolveAndFixSingleFunctionTemplateSpecialization(result, false)) {
13730       return result;
13731 
13732     // If that failed, try to recover with a call.
13733     } else {
13734       tryToRecoverWithCall(result, PDiag(diag::err_ovl_unresolvable),
13735                            /*complain*/ true);
13736       return result;
13737     }
13738   }
13739 
13740   // Bound member functions.
13741   case BuiltinType::BoundMember: {
13742     ExprResult result = E;
13743     tryToRecoverWithCall(result, PDiag(diag::err_bound_member_function),
13744                          /*complain*/ true);
13745     return result;
13746   }
13747 
13748   // ARC unbridged casts.
13749   case BuiltinType::ARCUnbridgedCast: {
13750     Expr *realCast = stripARCUnbridgedCast(E);
13751     diagnoseARCUnbridgedCast(realCast);
13752     return realCast;
13753   }
13754 
13755   // Expressions of unknown type.
13756   case BuiltinType::UnknownAny:
13757     return diagnoseUnknownAnyExpr(*this, E);
13758 
13759   // Pseudo-objects.
13760   case BuiltinType::PseudoObject:
13761     return checkPseudoObjectRValue(E);
13762 
13763   case BuiltinType::BuiltinFn: {
13764     // Accept __noop without parens by implicitly converting it to a call expr.
13765     auto *DRE = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts());
13766     if (DRE) {
13767       auto *FD = cast<FunctionDecl>(DRE->getDecl());
13768       if (FD->getBuiltinID() == Builtin::BI__noop) {
13769         E = ImpCastExprToType(E, Context.getPointerType(FD->getType()),
13770                               CK_BuiltinFnToFnPtr).get();
13771         return new (Context) CallExpr(Context, E, None, Context.IntTy,
13772                                       VK_RValue, SourceLocation());
13773       }
13774     }
13775 
13776     Diag(E->getLocStart(), diag::err_builtin_fn_use);
13777     return ExprError();
13778   }
13779 
13780   // Everything else should be impossible.
13781 #define BUILTIN_TYPE(Id, SingletonId) \
13782   case BuiltinType::Id:
13783 #define PLACEHOLDER_TYPE(Id, SingletonId)
13784 #include "clang/AST/BuiltinTypes.def"
13785     break;
13786   }
13787 
13788   llvm_unreachable("invalid placeholder type!");
13789 }
13790 
CheckCaseExpression(Expr * E)13791 bool Sema::CheckCaseExpression(Expr *E) {
13792   if (E->isTypeDependent())
13793     return true;
13794   if (E->isValueDependent() || E->isIntegerConstantExpr(Context))
13795     return E->getType()->isIntegralOrEnumerationType();
13796   return false;
13797 }
13798 
13799 /// ActOnObjCBoolLiteral - Parse {__objc_yes,__objc_no} literals.
13800 ExprResult
ActOnObjCBoolLiteral(SourceLocation OpLoc,tok::TokenKind Kind)13801 Sema::ActOnObjCBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind) {
13802   assert((Kind == tok::kw___objc_yes || Kind == tok::kw___objc_no) &&
13803          "Unknown Objective-C Boolean value!");
13804   QualType BoolT = Context.ObjCBuiltinBoolTy;
13805   if (!Context.getBOOLDecl()) {
13806     LookupResult Result(*this, &Context.Idents.get("BOOL"), OpLoc,
13807                         Sema::LookupOrdinaryName);
13808     if (LookupName(Result, getCurScope()) && Result.isSingleResult()) {
13809       NamedDecl *ND = Result.getFoundDecl();
13810       if (TypedefDecl *TD = dyn_cast<TypedefDecl>(ND))
13811         Context.setBOOLDecl(TD);
13812     }
13813   }
13814   if (Context.getBOOLDecl())
13815     BoolT = Context.getBOOLType();
13816   return new (Context)
13817       ObjCBoolLiteralExpr(Kind == tok::kw___objc_yes, BoolT, OpLoc);
13818 }
13819