1 //===--- SemaInit.cpp - Semantic Analysis for Initializers ----------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements semantic analysis for initializers.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "clang/AST/ASTContext.h"
14 #include "clang/AST/DeclObjC.h"
15 #include "clang/AST/ExprCXX.h"
16 #include "clang/AST/ExprObjC.h"
17 #include "clang/AST/ExprOpenMP.h"
18 #include "clang/AST/TypeLoc.h"
19 #include "clang/Basic/CharInfo.h"
20 #include "clang/Basic/TargetInfo.h"
21 #include "clang/Sema/Designator.h"
22 #include "clang/Sema/Initialization.h"
23 #include "clang/Sema/Lookup.h"
24 #include "clang/Sema/SemaInternal.h"
25 #include "llvm/ADT/APInt.h"
26 #include "llvm/ADT/SmallString.h"
27 #include "llvm/Support/ErrorHandling.h"
28 #include "llvm/Support/raw_ostream.h"
29
30 using namespace clang;
31
32 //===----------------------------------------------------------------------===//
33 // Sema Initialization Checking
34 //===----------------------------------------------------------------------===//
35
36 /// Check whether T is compatible with a wide character type (wchar_t,
37 /// char16_t or char32_t).
IsWideCharCompatible(QualType T,ASTContext & Context)38 static bool IsWideCharCompatible(QualType T, ASTContext &Context) {
39 if (Context.typesAreCompatible(Context.getWideCharType(), T))
40 return true;
41 if (Context.getLangOpts().CPlusPlus || Context.getLangOpts().C11) {
42 return Context.typesAreCompatible(Context.Char16Ty, T) ||
43 Context.typesAreCompatible(Context.Char32Ty, T);
44 }
45 return false;
46 }
47
48 enum StringInitFailureKind {
49 SIF_None,
50 SIF_NarrowStringIntoWideChar,
51 SIF_WideStringIntoChar,
52 SIF_IncompatWideStringIntoWideChar,
53 SIF_UTF8StringIntoPlainChar,
54 SIF_PlainStringIntoUTF8Char,
55 SIF_Other
56 };
57
58 /// Check whether the array of type AT can be initialized by the Init
59 /// expression by means of string initialization. Returns SIF_None if so,
60 /// otherwise returns a StringInitFailureKind that describes why the
61 /// initialization would not work.
IsStringInit(Expr * Init,const ArrayType * AT,ASTContext & Context)62 static StringInitFailureKind IsStringInit(Expr *Init, const ArrayType *AT,
63 ASTContext &Context) {
64 if (!isa<ConstantArrayType>(AT) && !isa<IncompleteArrayType>(AT))
65 return SIF_Other;
66
67 // See if this is a string literal or @encode.
68 Init = Init->IgnoreParens();
69
70 // Handle @encode, which is a narrow string.
71 if (isa<ObjCEncodeExpr>(Init) && AT->getElementType()->isCharType())
72 return SIF_None;
73
74 // Otherwise we can only handle string literals.
75 StringLiteral *SL = dyn_cast<StringLiteral>(Init);
76 if (!SL)
77 return SIF_Other;
78
79 const QualType ElemTy =
80 Context.getCanonicalType(AT->getElementType()).getUnqualifiedType();
81
82 switch (SL->getKind()) {
83 case StringLiteral::UTF8:
84 // char8_t array can be initialized with a UTF-8 string.
85 if (ElemTy->isChar8Type())
86 return SIF_None;
87 LLVM_FALLTHROUGH;
88 case StringLiteral::Ascii:
89 // char array can be initialized with a narrow string.
90 // Only allow char x[] = "foo"; not char x[] = L"foo";
91 if (ElemTy->isCharType())
92 return (SL->getKind() == StringLiteral::UTF8 &&
93 Context.getLangOpts().Char8)
94 ? SIF_UTF8StringIntoPlainChar
95 : SIF_None;
96 if (ElemTy->isChar8Type())
97 return SIF_PlainStringIntoUTF8Char;
98 if (IsWideCharCompatible(ElemTy, Context))
99 return SIF_NarrowStringIntoWideChar;
100 return SIF_Other;
101 // C99 6.7.8p15 (with correction from DR343), or C11 6.7.9p15:
102 // "An array with element type compatible with a qualified or unqualified
103 // version of wchar_t, char16_t, or char32_t may be initialized by a wide
104 // string literal with the corresponding encoding prefix (L, u, or U,
105 // respectively), optionally enclosed in braces.
106 case StringLiteral::UTF16:
107 if (Context.typesAreCompatible(Context.Char16Ty, ElemTy))
108 return SIF_None;
109 if (ElemTy->isCharType() || ElemTy->isChar8Type())
110 return SIF_WideStringIntoChar;
111 if (IsWideCharCompatible(ElemTy, Context))
112 return SIF_IncompatWideStringIntoWideChar;
113 return SIF_Other;
114 case StringLiteral::UTF32:
115 if (Context.typesAreCompatible(Context.Char32Ty, ElemTy))
116 return SIF_None;
117 if (ElemTy->isCharType() || ElemTy->isChar8Type())
118 return SIF_WideStringIntoChar;
119 if (IsWideCharCompatible(ElemTy, Context))
120 return SIF_IncompatWideStringIntoWideChar;
121 return SIF_Other;
122 case StringLiteral::Wide:
123 if (Context.typesAreCompatible(Context.getWideCharType(), ElemTy))
124 return SIF_None;
125 if (ElemTy->isCharType() || ElemTy->isChar8Type())
126 return SIF_WideStringIntoChar;
127 if (IsWideCharCompatible(ElemTy, Context))
128 return SIF_IncompatWideStringIntoWideChar;
129 return SIF_Other;
130 }
131
132 llvm_unreachable("missed a StringLiteral kind?");
133 }
134
IsStringInit(Expr * init,QualType declType,ASTContext & Context)135 static StringInitFailureKind IsStringInit(Expr *init, QualType declType,
136 ASTContext &Context) {
137 const ArrayType *arrayType = Context.getAsArrayType(declType);
138 if (!arrayType)
139 return SIF_Other;
140 return IsStringInit(init, arrayType, Context);
141 }
142
143 /// Update the type of a string literal, including any surrounding parentheses,
144 /// to match the type of the object which it is initializing.
updateStringLiteralType(Expr * E,QualType Ty)145 static void updateStringLiteralType(Expr *E, QualType Ty) {
146 while (true) {
147 E->setType(Ty);
148 E->setValueKind(VK_RValue);
149 if (isa<StringLiteral>(E) || isa<ObjCEncodeExpr>(E)) {
150 break;
151 } else if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
152 E = PE->getSubExpr();
153 } else if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
154 assert(UO->getOpcode() == UO_Extension);
155 E = UO->getSubExpr();
156 } else if (GenericSelectionExpr *GSE = dyn_cast<GenericSelectionExpr>(E)) {
157 E = GSE->getResultExpr();
158 } else if (ChooseExpr *CE = dyn_cast<ChooseExpr>(E)) {
159 E = CE->getChosenSubExpr();
160 } else {
161 llvm_unreachable("unexpected expr in string literal init");
162 }
163 }
164 }
165
166 /// Fix a compound literal initializing an array so it's correctly marked
167 /// as an rvalue.
updateGNUCompoundLiteralRValue(Expr * E)168 static void updateGNUCompoundLiteralRValue(Expr *E) {
169 while (true) {
170 E->setValueKind(VK_RValue);
171 if (isa<CompoundLiteralExpr>(E)) {
172 break;
173 } else if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
174 E = PE->getSubExpr();
175 } else if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
176 assert(UO->getOpcode() == UO_Extension);
177 E = UO->getSubExpr();
178 } else if (GenericSelectionExpr *GSE = dyn_cast<GenericSelectionExpr>(E)) {
179 E = GSE->getResultExpr();
180 } else if (ChooseExpr *CE = dyn_cast<ChooseExpr>(E)) {
181 E = CE->getChosenSubExpr();
182 } else {
183 llvm_unreachable("unexpected expr in array compound literal init");
184 }
185 }
186 }
187
CheckStringInit(Expr * Str,QualType & DeclT,const ArrayType * AT,Sema & S)188 static void CheckStringInit(Expr *Str, QualType &DeclT, const ArrayType *AT,
189 Sema &S) {
190 // Get the length of the string as parsed.
191 auto *ConstantArrayTy =
192 cast<ConstantArrayType>(Str->getType()->getAsArrayTypeUnsafe());
193 uint64_t StrLength = ConstantArrayTy->getSize().getZExtValue();
194
195 if (const IncompleteArrayType *IAT = dyn_cast<IncompleteArrayType>(AT)) {
196 // C99 6.7.8p14. We have an array of character type with unknown size
197 // being initialized to a string literal.
198 llvm::APInt ConstVal(32, StrLength);
199 // Return a new array type (C99 6.7.8p22).
200 DeclT = S.Context.getConstantArrayType(IAT->getElementType(),
201 ConstVal, nullptr,
202 ArrayType::Normal, 0);
203 updateStringLiteralType(Str, DeclT);
204 return;
205 }
206
207 const ConstantArrayType *CAT = cast<ConstantArrayType>(AT);
208
209 // We have an array of character type with known size. However,
210 // the size may be smaller or larger than the string we are initializing.
211 // FIXME: Avoid truncation for 64-bit length strings.
212 if (S.getLangOpts().CPlusPlus) {
213 if (StringLiteral *SL = dyn_cast<StringLiteral>(Str->IgnoreParens())) {
214 // For Pascal strings it's OK to strip off the terminating null character,
215 // so the example below is valid:
216 //
217 // unsigned char a[2] = "\pa";
218 if (SL->isPascal())
219 StrLength--;
220 }
221
222 // [dcl.init.string]p2
223 if (StrLength > CAT->getSize().getZExtValue())
224 S.Diag(Str->getBeginLoc(),
225 diag::err_initializer_string_for_char_array_too_long)
226 << Str->getSourceRange();
227 } else {
228 // C99 6.7.8p14.
229 if (StrLength-1 > CAT->getSize().getZExtValue())
230 S.Diag(Str->getBeginLoc(),
231 diag::ext_initializer_string_for_char_array_too_long)
232 << Str->getSourceRange();
233 }
234
235 // Set the type to the actual size that we are initializing. If we have
236 // something like:
237 // char x[1] = "foo";
238 // then this will set the string literal's type to char[1].
239 updateStringLiteralType(Str, DeclT);
240 }
241
242 //===----------------------------------------------------------------------===//
243 // Semantic checking for initializer lists.
244 //===----------------------------------------------------------------------===//
245
246 namespace {
247
248 /// Semantic checking for initializer lists.
249 ///
250 /// The InitListChecker class contains a set of routines that each
251 /// handle the initialization of a certain kind of entity, e.g.,
252 /// arrays, vectors, struct/union types, scalars, etc. The
253 /// InitListChecker itself performs a recursive walk of the subobject
254 /// structure of the type to be initialized, while stepping through
255 /// the initializer list one element at a time. The IList and Index
256 /// parameters to each of the Check* routines contain the active
257 /// (syntactic) initializer list and the index into that initializer
258 /// list that represents the current initializer. Each routine is
259 /// responsible for moving that Index forward as it consumes elements.
260 ///
261 /// Each Check* routine also has a StructuredList/StructuredIndex
262 /// arguments, which contains the current "structured" (semantic)
263 /// initializer list and the index into that initializer list where we
264 /// are copying initializers as we map them over to the semantic
265 /// list. Once we have completed our recursive walk of the subobject
266 /// structure, we will have constructed a full semantic initializer
267 /// list.
268 ///
269 /// C99 designators cause changes in the initializer list traversal,
270 /// because they make the initialization "jump" into a specific
271 /// subobject and then continue the initialization from that
272 /// point. CheckDesignatedInitializer() recursively steps into the
273 /// designated subobject and manages backing out the recursion to
274 /// initialize the subobjects after the one designated.
275 ///
276 /// If an initializer list contains any designators, we build a placeholder
277 /// structured list even in 'verify only' mode, so that we can track which
278 /// elements need 'empty' initializtion.
279 class InitListChecker {
280 Sema &SemaRef;
281 bool hadError = false;
282 bool VerifyOnly; // No diagnostics.
283 bool TreatUnavailableAsInvalid; // Used only in VerifyOnly mode.
284 bool InOverloadResolution;
285 InitListExpr *FullyStructuredList = nullptr;
286 NoInitExpr *DummyExpr = nullptr;
287
getDummyInit()288 NoInitExpr *getDummyInit() {
289 if (!DummyExpr)
290 DummyExpr = new (SemaRef.Context) NoInitExpr(SemaRef.Context.VoidTy);
291 return DummyExpr;
292 }
293
294 void CheckImplicitInitList(const InitializedEntity &Entity,
295 InitListExpr *ParentIList, QualType T,
296 unsigned &Index, InitListExpr *StructuredList,
297 unsigned &StructuredIndex);
298 void CheckExplicitInitList(const InitializedEntity &Entity,
299 InitListExpr *IList, QualType &T,
300 InitListExpr *StructuredList,
301 bool TopLevelObject = false);
302 void CheckListElementTypes(const InitializedEntity &Entity,
303 InitListExpr *IList, QualType &DeclType,
304 bool SubobjectIsDesignatorContext,
305 unsigned &Index,
306 InitListExpr *StructuredList,
307 unsigned &StructuredIndex,
308 bool TopLevelObject = false);
309 void CheckSubElementType(const InitializedEntity &Entity,
310 InitListExpr *IList, QualType ElemType,
311 unsigned &Index,
312 InitListExpr *StructuredList,
313 unsigned &StructuredIndex);
314 void CheckComplexType(const InitializedEntity &Entity,
315 InitListExpr *IList, QualType DeclType,
316 unsigned &Index,
317 InitListExpr *StructuredList,
318 unsigned &StructuredIndex);
319 void CheckScalarType(const InitializedEntity &Entity,
320 InitListExpr *IList, QualType DeclType,
321 unsigned &Index,
322 InitListExpr *StructuredList,
323 unsigned &StructuredIndex);
324 void CheckReferenceType(const InitializedEntity &Entity,
325 InitListExpr *IList, QualType DeclType,
326 unsigned &Index,
327 InitListExpr *StructuredList,
328 unsigned &StructuredIndex);
329 void CheckVectorType(const InitializedEntity &Entity,
330 InitListExpr *IList, QualType DeclType, unsigned &Index,
331 InitListExpr *StructuredList,
332 unsigned &StructuredIndex);
333 void CheckStructUnionTypes(const InitializedEntity &Entity,
334 InitListExpr *IList, QualType DeclType,
335 CXXRecordDecl::base_class_range Bases,
336 RecordDecl::field_iterator Field,
337 bool SubobjectIsDesignatorContext, unsigned &Index,
338 InitListExpr *StructuredList,
339 unsigned &StructuredIndex,
340 bool TopLevelObject = false);
341 void CheckArrayType(const InitializedEntity &Entity,
342 InitListExpr *IList, QualType &DeclType,
343 llvm::APSInt elementIndex,
344 bool SubobjectIsDesignatorContext, unsigned &Index,
345 InitListExpr *StructuredList,
346 unsigned &StructuredIndex);
347 bool CheckDesignatedInitializer(const InitializedEntity &Entity,
348 InitListExpr *IList, DesignatedInitExpr *DIE,
349 unsigned DesigIdx,
350 QualType &CurrentObjectType,
351 RecordDecl::field_iterator *NextField,
352 llvm::APSInt *NextElementIndex,
353 unsigned &Index,
354 InitListExpr *StructuredList,
355 unsigned &StructuredIndex,
356 bool FinishSubobjectInit,
357 bool TopLevelObject);
358 InitListExpr *getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
359 QualType CurrentObjectType,
360 InitListExpr *StructuredList,
361 unsigned StructuredIndex,
362 SourceRange InitRange,
363 bool IsFullyOverwritten = false);
364 void UpdateStructuredListElement(InitListExpr *StructuredList,
365 unsigned &StructuredIndex,
366 Expr *expr);
367 InitListExpr *createInitListExpr(QualType CurrentObjectType,
368 SourceRange InitRange,
369 unsigned ExpectedNumInits);
370 int numArrayElements(QualType DeclType);
371 int numStructUnionElements(QualType DeclType);
372
373 ExprResult PerformEmptyInit(SourceLocation Loc,
374 const InitializedEntity &Entity);
375
376 /// Diagnose that OldInit (or part thereof) has been overridden by NewInit.
diagnoseInitOverride(Expr * OldInit,SourceRange NewInitRange,bool FullyOverwritten=true)377 void diagnoseInitOverride(Expr *OldInit, SourceRange NewInitRange,
378 bool FullyOverwritten = true) {
379 // Overriding an initializer via a designator is valid with C99 designated
380 // initializers, but ill-formed with C++20 designated initializers.
381 unsigned DiagID = SemaRef.getLangOpts().CPlusPlus
382 ? diag::ext_initializer_overrides
383 : diag::warn_initializer_overrides;
384
385 if (InOverloadResolution && SemaRef.getLangOpts().CPlusPlus) {
386 // In overload resolution, we have to strictly enforce the rules, and so
387 // don't allow any overriding of prior initializers. This matters for a
388 // case such as:
389 //
390 // union U { int a, b; };
391 // struct S { int a, b; };
392 // void f(U), f(S);
393 //
394 // Here, f({.a = 1, .b = 2}) is required to call the struct overload. For
395 // consistency, we disallow all overriding of prior initializers in
396 // overload resolution, not only overriding of union members.
397 hadError = true;
398 } else if (OldInit->getType().isDestructedType() && !FullyOverwritten) {
399 // If we'll be keeping around the old initializer but overwriting part of
400 // the object it initialized, and that object is not trivially
401 // destructible, this can leak. Don't allow that, not even as an
402 // extension.
403 //
404 // FIXME: It might be reasonable to allow this in cases where the part of
405 // the initializer that we're overriding has trivial destruction.
406 DiagID = diag::err_initializer_overrides_destructed;
407 } else if (!OldInit->getSourceRange().isValid()) {
408 // We need to check on source range validity because the previous
409 // initializer does not have to be an explicit initializer. e.g.,
410 //
411 // struct P { int a, b; };
412 // struct PP { struct P p } l = { { .a = 2 }, .p.b = 3 };
413 //
414 // There is an overwrite taking place because the first braced initializer
415 // list "{ .a = 2 }" already provides value for .p.b (which is zero).
416 //
417 // Such overwrites are harmless, so we don't diagnose them. (Note that in
418 // C++, this cannot be reached unless we've already seen and diagnosed a
419 // different conformance issue, such as a mixture of designated and
420 // non-designated initializers or a multi-level designator.)
421 return;
422 }
423
424 if (!VerifyOnly) {
425 SemaRef.Diag(NewInitRange.getBegin(), DiagID)
426 << NewInitRange << FullyOverwritten << OldInit->getType();
427 SemaRef.Diag(OldInit->getBeginLoc(), diag::note_previous_initializer)
428 << (OldInit->HasSideEffects(SemaRef.Context) && FullyOverwritten)
429 << OldInit->getSourceRange();
430 }
431 }
432
433 // Explanation on the "FillWithNoInit" mode:
434 //
435 // Assume we have the following definitions (Case#1):
436 // struct P { char x[6][6]; } xp = { .x[1] = "bar" };
437 // struct PP { struct P lp; } l = { .lp = xp, .lp.x[1][2] = 'f' };
438 //
439 // l.lp.x[1][0..1] should not be filled with implicit initializers because the
440 // "base" initializer "xp" will provide values for them; l.lp.x[1] will be "baf".
441 //
442 // But if we have (Case#2):
443 // struct PP l = { .lp = xp, .lp.x[1] = { [2] = 'f' } };
444 //
445 // l.lp.x[1][0..1] are implicitly initialized and do not use values from the
446 // "base" initializer; l.lp.x[1] will be "\0\0f\0\0\0".
447 //
448 // To distinguish Case#1 from Case#2, and also to avoid leaving many "holes"
449 // in the InitListExpr, the "holes" in Case#1 are filled not with empty
450 // initializers but with special "NoInitExpr" place holders, which tells the
451 // CodeGen not to generate any initializers for these parts.
452 void FillInEmptyInitForBase(unsigned Init, const CXXBaseSpecifier &Base,
453 const InitializedEntity &ParentEntity,
454 InitListExpr *ILE, bool &RequiresSecondPass,
455 bool FillWithNoInit);
456 void FillInEmptyInitForField(unsigned Init, FieldDecl *Field,
457 const InitializedEntity &ParentEntity,
458 InitListExpr *ILE, bool &RequiresSecondPass,
459 bool FillWithNoInit = false);
460 void FillInEmptyInitializations(const InitializedEntity &Entity,
461 InitListExpr *ILE, bool &RequiresSecondPass,
462 InitListExpr *OuterILE, unsigned OuterIndex,
463 bool FillWithNoInit = false);
464 bool CheckFlexibleArrayInit(const InitializedEntity &Entity,
465 Expr *InitExpr, FieldDecl *Field,
466 bool TopLevelObject);
467 void CheckEmptyInitializable(const InitializedEntity &Entity,
468 SourceLocation Loc);
469
470 public:
471 InitListChecker(Sema &S, const InitializedEntity &Entity, InitListExpr *IL,
472 QualType &T, bool VerifyOnly, bool TreatUnavailableAsInvalid,
473 bool InOverloadResolution = false);
HadError()474 bool HadError() { return hadError; }
475
476 // Retrieves the fully-structured initializer list used for
477 // semantic analysis and code generation.
getFullyStructuredList() const478 InitListExpr *getFullyStructuredList() const { return FullyStructuredList; }
479 };
480
481 } // end anonymous namespace
482
PerformEmptyInit(SourceLocation Loc,const InitializedEntity & Entity)483 ExprResult InitListChecker::PerformEmptyInit(SourceLocation Loc,
484 const InitializedEntity &Entity) {
485 InitializationKind Kind = InitializationKind::CreateValue(Loc, Loc, Loc,
486 true);
487 MultiExprArg SubInit;
488 Expr *InitExpr;
489 InitListExpr DummyInitList(SemaRef.Context, Loc, None, Loc);
490
491 // C++ [dcl.init.aggr]p7:
492 // If there are fewer initializer-clauses in the list than there are
493 // members in the aggregate, then each member not explicitly initialized
494 // ...
495 bool EmptyInitList = SemaRef.getLangOpts().CPlusPlus11 &&
496 Entity.getType()->getBaseElementTypeUnsafe()->isRecordType();
497 if (EmptyInitList) {
498 // C++1y / DR1070:
499 // shall be initialized [...] from an empty initializer list.
500 //
501 // We apply the resolution of this DR to C++11 but not C++98, since C++98
502 // does not have useful semantics for initialization from an init list.
503 // We treat this as copy-initialization, because aggregate initialization
504 // always performs copy-initialization on its elements.
505 //
506 // Only do this if we're initializing a class type, to avoid filling in
507 // the initializer list where possible.
508 InitExpr = VerifyOnly ? &DummyInitList : new (SemaRef.Context)
509 InitListExpr(SemaRef.Context, Loc, None, Loc);
510 InitExpr->setType(SemaRef.Context.VoidTy);
511 SubInit = InitExpr;
512 Kind = InitializationKind::CreateCopy(Loc, Loc);
513 } else {
514 // C++03:
515 // shall be value-initialized.
516 }
517
518 InitializationSequence InitSeq(SemaRef, Entity, Kind, SubInit);
519 // libstdc++4.6 marks the vector default constructor as explicit in
520 // _GLIBCXX_DEBUG mode, so recover using the C++03 logic in that case.
521 // stlport does so too. Look for std::__debug for libstdc++, and for
522 // std:: for stlport. This is effectively a compiler-side implementation of
523 // LWG2193.
524 if (!InitSeq && EmptyInitList && InitSeq.getFailureKind() ==
525 InitializationSequence::FK_ExplicitConstructor) {
526 OverloadCandidateSet::iterator Best;
527 OverloadingResult O =
528 InitSeq.getFailedCandidateSet()
529 .BestViableFunction(SemaRef, Kind.getLocation(), Best);
530 (void)O;
531 assert(O == OR_Success && "Inconsistent overload resolution");
532 CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
533 CXXRecordDecl *R = CtorDecl->getParent();
534
535 if (CtorDecl->getMinRequiredArguments() == 0 &&
536 CtorDecl->isExplicit() && R->getDeclName() &&
537 SemaRef.SourceMgr.isInSystemHeader(CtorDecl->getLocation())) {
538 bool IsInStd = false;
539 for (NamespaceDecl *ND = dyn_cast<NamespaceDecl>(R->getDeclContext());
540 ND && !IsInStd; ND = dyn_cast<NamespaceDecl>(ND->getParent())) {
541 if (SemaRef.getStdNamespace()->InEnclosingNamespaceSetOf(ND))
542 IsInStd = true;
543 }
544
545 if (IsInStd && llvm::StringSwitch<bool>(R->getName())
546 .Cases("basic_string", "deque", "forward_list", true)
547 .Cases("list", "map", "multimap", "multiset", true)
548 .Cases("priority_queue", "queue", "set", "stack", true)
549 .Cases("unordered_map", "unordered_set", "vector", true)
550 .Default(false)) {
551 InitSeq.InitializeFrom(
552 SemaRef, Entity,
553 InitializationKind::CreateValue(Loc, Loc, Loc, true),
554 MultiExprArg(), /*TopLevelOfInitList=*/false,
555 TreatUnavailableAsInvalid);
556 // Emit a warning for this. System header warnings aren't shown
557 // by default, but people working on system headers should see it.
558 if (!VerifyOnly) {
559 SemaRef.Diag(CtorDecl->getLocation(),
560 diag::warn_invalid_initializer_from_system_header);
561 if (Entity.getKind() == InitializedEntity::EK_Member)
562 SemaRef.Diag(Entity.getDecl()->getLocation(),
563 diag::note_used_in_initialization_here);
564 else if (Entity.getKind() == InitializedEntity::EK_ArrayElement)
565 SemaRef.Diag(Loc, diag::note_used_in_initialization_here);
566 }
567 }
568 }
569 }
570 if (!InitSeq) {
571 if (!VerifyOnly) {
572 InitSeq.Diagnose(SemaRef, Entity, Kind, SubInit);
573 if (Entity.getKind() == InitializedEntity::EK_Member)
574 SemaRef.Diag(Entity.getDecl()->getLocation(),
575 diag::note_in_omitted_aggregate_initializer)
576 << /*field*/1 << Entity.getDecl();
577 else if (Entity.getKind() == InitializedEntity::EK_ArrayElement) {
578 bool IsTrailingArrayNewMember =
579 Entity.getParent() &&
580 Entity.getParent()->isVariableLengthArrayNew();
581 SemaRef.Diag(Loc, diag::note_in_omitted_aggregate_initializer)
582 << (IsTrailingArrayNewMember ? 2 : /*array element*/0)
583 << Entity.getElementIndex();
584 }
585 }
586 hadError = true;
587 return ExprError();
588 }
589
590 return VerifyOnly ? ExprResult()
591 : InitSeq.Perform(SemaRef, Entity, Kind, SubInit);
592 }
593
CheckEmptyInitializable(const InitializedEntity & Entity,SourceLocation Loc)594 void InitListChecker::CheckEmptyInitializable(const InitializedEntity &Entity,
595 SourceLocation Loc) {
596 // If we're building a fully-structured list, we'll check this at the end
597 // once we know which elements are actually initialized. Otherwise, we know
598 // that there are no designators so we can just check now.
599 if (FullyStructuredList)
600 return;
601 PerformEmptyInit(Loc, Entity);
602 }
603
FillInEmptyInitForBase(unsigned Init,const CXXBaseSpecifier & Base,const InitializedEntity & ParentEntity,InitListExpr * ILE,bool & RequiresSecondPass,bool FillWithNoInit)604 void InitListChecker::FillInEmptyInitForBase(
605 unsigned Init, const CXXBaseSpecifier &Base,
606 const InitializedEntity &ParentEntity, InitListExpr *ILE,
607 bool &RequiresSecondPass, bool FillWithNoInit) {
608 InitializedEntity BaseEntity = InitializedEntity::InitializeBase(
609 SemaRef.Context, &Base, false, &ParentEntity);
610
611 if (Init >= ILE->getNumInits() || !ILE->getInit(Init)) {
612 ExprResult BaseInit = FillWithNoInit
613 ? new (SemaRef.Context) NoInitExpr(Base.getType())
614 : PerformEmptyInit(ILE->getEndLoc(), BaseEntity);
615 if (BaseInit.isInvalid()) {
616 hadError = true;
617 return;
618 }
619
620 if (!VerifyOnly) {
621 assert(Init < ILE->getNumInits() && "should have been expanded");
622 ILE->setInit(Init, BaseInit.getAs<Expr>());
623 }
624 } else if (InitListExpr *InnerILE =
625 dyn_cast<InitListExpr>(ILE->getInit(Init))) {
626 FillInEmptyInitializations(BaseEntity, InnerILE, RequiresSecondPass,
627 ILE, Init, FillWithNoInit);
628 } else if (DesignatedInitUpdateExpr *InnerDIUE =
629 dyn_cast<DesignatedInitUpdateExpr>(ILE->getInit(Init))) {
630 FillInEmptyInitializations(BaseEntity, InnerDIUE->getUpdater(),
631 RequiresSecondPass, ILE, Init,
632 /*FillWithNoInit =*/true);
633 }
634 }
635
FillInEmptyInitForField(unsigned Init,FieldDecl * Field,const InitializedEntity & ParentEntity,InitListExpr * ILE,bool & RequiresSecondPass,bool FillWithNoInit)636 void InitListChecker::FillInEmptyInitForField(unsigned Init, FieldDecl *Field,
637 const InitializedEntity &ParentEntity,
638 InitListExpr *ILE,
639 bool &RequiresSecondPass,
640 bool FillWithNoInit) {
641 SourceLocation Loc = ILE->getEndLoc();
642 unsigned NumInits = ILE->getNumInits();
643 InitializedEntity MemberEntity
644 = InitializedEntity::InitializeMember(Field, &ParentEntity);
645
646 if (Init >= NumInits || !ILE->getInit(Init)) {
647 if (const RecordType *RType = ILE->getType()->getAs<RecordType>())
648 if (!RType->getDecl()->isUnion())
649 assert((Init < NumInits || VerifyOnly) &&
650 "This ILE should have been expanded");
651
652 if (FillWithNoInit) {
653 assert(!VerifyOnly && "should not fill with no-init in verify-only mode");
654 Expr *Filler = new (SemaRef.Context) NoInitExpr(Field->getType());
655 if (Init < NumInits)
656 ILE->setInit(Init, Filler);
657 else
658 ILE->updateInit(SemaRef.Context, Init, Filler);
659 return;
660 }
661 // C++1y [dcl.init.aggr]p7:
662 // If there are fewer initializer-clauses in the list than there are
663 // members in the aggregate, then each member not explicitly initialized
664 // shall be initialized from its brace-or-equal-initializer [...]
665 if (Field->hasInClassInitializer()) {
666 if (VerifyOnly)
667 return;
668
669 ExprResult DIE = SemaRef.BuildCXXDefaultInitExpr(Loc, Field);
670 if (DIE.isInvalid()) {
671 hadError = true;
672 return;
673 }
674 SemaRef.checkInitializerLifetime(MemberEntity, DIE.get());
675 if (Init < NumInits)
676 ILE->setInit(Init, DIE.get());
677 else {
678 ILE->updateInit(SemaRef.Context, Init, DIE.get());
679 RequiresSecondPass = true;
680 }
681 return;
682 }
683
684 if (Field->getType()->isReferenceType()) {
685 if (!VerifyOnly) {
686 // C++ [dcl.init.aggr]p9:
687 // If an incomplete or empty initializer-list leaves a
688 // member of reference type uninitialized, the program is
689 // ill-formed.
690 SemaRef.Diag(Loc, diag::err_init_reference_member_uninitialized)
691 << Field->getType()
692 << ILE->getSyntacticForm()->getSourceRange();
693 SemaRef.Diag(Field->getLocation(),
694 diag::note_uninit_reference_member);
695 }
696 hadError = true;
697 return;
698 }
699
700 ExprResult MemberInit = PerformEmptyInit(Loc, MemberEntity);
701 if (MemberInit.isInvalid()) {
702 hadError = true;
703 return;
704 }
705
706 if (hadError || VerifyOnly) {
707 // Do nothing
708 } else if (Init < NumInits) {
709 ILE->setInit(Init, MemberInit.getAs<Expr>());
710 } else if (!isa<ImplicitValueInitExpr>(MemberInit.get())) {
711 // Empty initialization requires a constructor call, so
712 // extend the initializer list to include the constructor
713 // call and make a note that we'll need to take another pass
714 // through the initializer list.
715 ILE->updateInit(SemaRef.Context, Init, MemberInit.getAs<Expr>());
716 RequiresSecondPass = true;
717 }
718 } else if (InitListExpr *InnerILE
719 = dyn_cast<InitListExpr>(ILE->getInit(Init))) {
720 FillInEmptyInitializations(MemberEntity, InnerILE,
721 RequiresSecondPass, ILE, Init, FillWithNoInit);
722 } else if (DesignatedInitUpdateExpr *InnerDIUE =
723 dyn_cast<DesignatedInitUpdateExpr>(ILE->getInit(Init))) {
724 FillInEmptyInitializations(MemberEntity, InnerDIUE->getUpdater(),
725 RequiresSecondPass, ILE, Init,
726 /*FillWithNoInit =*/true);
727 }
728 }
729
730 /// Recursively replaces NULL values within the given initializer list
731 /// with expressions that perform value-initialization of the
732 /// appropriate type, and finish off the InitListExpr formation.
733 void
FillInEmptyInitializations(const InitializedEntity & Entity,InitListExpr * ILE,bool & RequiresSecondPass,InitListExpr * OuterILE,unsigned OuterIndex,bool FillWithNoInit)734 InitListChecker::FillInEmptyInitializations(const InitializedEntity &Entity,
735 InitListExpr *ILE,
736 bool &RequiresSecondPass,
737 InitListExpr *OuterILE,
738 unsigned OuterIndex,
739 bool FillWithNoInit) {
740 assert((ILE->getType() != SemaRef.Context.VoidTy) &&
741 "Should not have void type");
742
743 // We don't need to do any checks when just filling NoInitExprs; that can't
744 // fail.
745 if (FillWithNoInit && VerifyOnly)
746 return;
747
748 // If this is a nested initializer list, we might have changed its contents
749 // (and therefore some of its properties, such as instantiation-dependence)
750 // while filling it in. Inform the outer initializer list so that its state
751 // can be updated to match.
752 // FIXME: We should fully build the inner initializers before constructing
753 // the outer InitListExpr instead of mutating AST nodes after they have
754 // been used as subexpressions of other nodes.
755 struct UpdateOuterILEWithUpdatedInit {
756 InitListExpr *Outer;
757 unsigned OuterIndex;
758 ~UpdateOuterILEWithUpdatedInit() {
759 if (Outer)
760 Outer->setInit(OuterIndex, Outer->getInit(OuterIndex));
761 }
762 } UpdateOuterRAII = {OuterILE, OuterIndex};
763
764 // A transparent ILE is not performing aggregate initialization and should
765 // not be filled in.
766 if (ILE->isTransparent())
767 return;
768
769 if (const RecordType *RType = ILE->getType()->getAs<RecordType>()) {
770 const RecordDecl *RDecl = RType->getDecl();
771 if (RDecl->isUnion() && ILE->getInitializedFieldInUnion())
772 FillInEmptyInitForField(0, ILE->getInitializedFieldInUnion(),
773 Entity, ILE, RequiresSecondPass, FillWithNoInit);
774 else if (RDecl->isUnion() && isa<CXXRecordDecl>(RDecl) &&
775 cast<CXXRecordDecl>(RDecl)->hasInClassInitializer()) {
776 for (auto *Field : RDecl->fields()) {
777 if (Field->hasInClassInitializer()) {
778 FillInEmptyInitForField(0, Field, Entity, ILE, RequiresSecondPass,
779 FillWithNoInit);
780 break;
781 }
782 }
783 } else {
784 // The fields beyond ILE->getNumInits() are default initialized, so in
785 // order to leave them uninitialized, the ILE is expanded and the extra
786 // fields are then filled with NoInitExpr.
787 unsigned NumElems = numStructUnionElements(ILE->getType());
788 if (RDecl->hasFlexibleArrayMember())
789 ++NumElems;
790 if (!VerifyOnly && ILE->getNumInits() < NumElems)
791 ILE->resizeInits(SemaRef.Context, NumElems);
792
793 unsigned Init = 0;
794
795 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RDecl)) {
796 for (auto &Base : CXXRD->bases()) {
797 if (hadError)
798 return;
799
800 FillInEmptyInitForBase(Init, Base, Entity, ILE, RequiresSecondPass,
801 FillWithNoInit);
802 ++Init;
803 }
804 }
805
806 for (auto *Field : RDecl->fields()) {
807 if (Field->isUnnamedBitfield())
808 continue;
809
810 if (hadError)
811 return;
812
813 FillInEmptyInitForField(Init, Field, Entity, ILE, RequiresSecondPass,
814 FillWithNoInit);
815 if (hadError)
816 return;
817
818 ++Init;
819
820 // Only look at the first initialization of a union.
821 if (RDecl->isUnion())
822 break;
823 }
824 }
825
826 return;
827 }
828
829 QualType ElementType;
830
831 InitializedEntity ElementEntity = Entity;
832 unsigned NumInits = ILE->getNumInits();
833 unsigned NumElements = NumInits;
834 if (const ArrayType *AType = SemaRef.Context.getAsArrayType(ILE->getType())) {
835 ElementType = AType->getElementType();
836 if (const auto *CAType = dyn_cast<ConstantArrayType>(AType))
837 NumElements = CAType->getSize().getZExtValue();
838 // For an array new with an unknown bound, ask for one additional element
839 // in order to populate the array filler.
840 if (Entity.isVariableLengthArrayNew())
841 ++NumElements;
842 ElementEntity = InitializedEntity::InitializeElement(SemaRef.Context,
843 0, Entity);
844 } else if (const VectorType *VType = ILE->getType()->getAs<VectorType>()) {
845 ElementType = VType->getElementType();
846 NumElements = VType->getNumElements();
847 ElementEntity = InitializedEntity::InitializeElement(SemaRef.Context,
848 0, Entity);
849 } else
850 ElementType = ILE->getType();
851
852 bool SkipEmptyInitChecks = false;
853 for (unsigned Init = 0; Init != NumElements; ++Init) {
854 if (hadError)
855 return;
856
857 if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement ||
858 ElementEntity.getKind() == InitializedEntity::EK_VectorElement)
859 ElementEntity.setElementIndex(Init);
860
861 if (Init >= NumInits && (ILE->hasArrayFiller() || SkipEmptyInitChecks))
862 return;
863
864 Expr *InitExpr = (Init < NumInits ? ILE->getInit(Init) : nullptr);
865 if (!InitExpr && Init < NumInits && ILE->hasArrayFiller())
866 ILE->setInit(Init, ILE->getArrayFiller());
867 else if (!InitExpr && !ILE->hasArrayFiller()) {
868 // In VerifyOnly mode, there's no point performing empty initialization
869 // more than once.
870 if (SkipEmptyInitChecks)
871 continue;
872
873 Expr *Filler = nullptr;
874
875 if (FillWithNoInit)
876 Filler = new (SemaRef.Context) NoInitExpr(ElementType);
877 else {
878 ExprResult ElementInit =
879 PerformEmptyInit(ILE->getEndLoc(), ElementEntity);
880 if (ElementInit.isInvalid()) {
881 hadError = true;
882 return;
883 }
884
885 Filler = ElementInit.getAs<Expr>();
886 }
887
888 if (hadError) {
889 // Do nothing
890 } else if (VerifyOnly) {
891 SkipEmptyInitChecks = true;
892 } else if (Init < NumInits) {
893 // For arrays, just set the expression used for value-initialization
894 // of the "holes" in the array.
895 if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement)
896 ILE->setArrayFiller(Filler);
897 else
898 ILE->setInit(Init, Filler);
899 } else {
900 // For arrays, just set the expression used for value-initialization
901 // of the rest of elements and exit.
902 if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement) {
903 ILE->setArrayFiller(Filler);
904 return;
905 }
906
907 if (!isa<ImplicitValueInitExpr>(Filler) && !isa<NoInitExpr>(Filler)) {
908 // Empty initialization requires a constructor call, so
909 // extend the initializer list to include the constructor
910 // call and make a note that we'll need to take another pass
911 // through the initializer list.
912 ILE->updateInit(SemaRef.Context, Init, Filler);
913 RequiresSecondPass = true;
914 }
915 }
916 } else if (InitListExpr *InnerILE
917 = dyn_cast_or_null<InitListExpr>(InitExpr)) {
918 FillInEmptyInitializations(ElementEntity, InnerILE, RequiresSecondPass,
919 ILE, Init, FillWithNoInit);
920 } else if (DesignatedInitUpdateExpr *InnerDIUE =
921 dyn_cast_or_null<DesignatedInitUpdateExpr>(InitExpr)) {
922 FillInEmptyInitializations(ElementEntity, InnerDIUE->getUpdater(),
923 RequiresSecondPass, ILE, Init,
924 /*FillWithNoInit =*/true);
925 }
926 }
927 }
928
hasAnyDesignatedInits(const InitListExpr * IL)929 static bool hasAnyDesignatedInits(const InitListExpr *IL) {
930 for (const Stmt *Init : *IL)
931 if (Init && isa<DesignatedInitExpr>(Init))
932 return true;
933 return false;
934 }
935
InitListChecker(Sema & S,const InitializedEntity & Entity,InitListExpr * IL,QualType & T,bool VerifyOnly,bool TreatUnavailableAsInvalid,bool InOverloadResolution)936 InitListChecker::InitListChecker(Sema &S, const InitializedEntity &Entity,
937 InitListExpr *IL, QualType &T, bool VerifyOnly,
938 bool TreatUnavailableAsInvalid,
939 bool InOverloadResolution)
940 : SemaRef(S), VerifyOnly(VerifyOnly),
941 TreatUnavailableAsInvalid(TreatUnavailableAsInvalid),
942 InOverloadResolution(InOverloadResolution) {
943 if (!VerifyOnly || hasAnyDesignatedInits(IL)) {
944 FullyStructuredList =
945 createInitListExpr(T, IL->getSourceRange(), IL->getNumInits());
946
947 // FIXME: Check that IL isn't already the semantic form of some other
948 // InitListExpr. If it is, we'd create a broken AST.
949 if (!VerifyOnly)
950 FullyStructuredList->setSyntacticForm(IL);
951 }
952
953 CheckExplicitInitList(Entity, IL, T, FullyStructuredList,
954 /*TopLevelObject=*/true);
955
956 if (!hadError && FullyStructuredList) {
957 bool RequiresSecondPass = false;
958 FillInEmptyInitializations(Entity, FullyStructuredList, RequiresSecondPass,
959 /*OuterILE=*/nullptr, /*OuterIndex=*/0);
960 if (RequiresSecondPass && !hadError)
961 FillInEmptyInitializations(Entity, FullyStructuredList,
962 RequiresSecondPass, nullptr, 0);
963 }
964 }
965
numArrayElements(QualType DeclType)966 int InitListChecker::numArrayElements(QualType DeclType) {
967 // FIXME: use a proper constant
968 int maxElements = 0x7FFFFFFF;
969 if (const ConstantArrayType *CAT =
970 SemaRef.Context.getAsConstantArrayType(DeclType)) {
971 maxElements = static_cast<int>(CAT->getSize().getZExtValue());
972 }
973 return maxElements;
974 }
975
numStructUnionElements(QualType DeclType)976 int InitListChecker::numStructUnionElements(QualType DeclType) {
977 RecordDecl *structDecl = DeclType->castAs<RecordType>()->getDecl();
978 int InitializableMembers = 0;
979 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(structDecl))
980 InitializableMembers += CXXRD->getNumBases();
981 for (const auto *Field : structDecl->fields())
982 if (!Field->isUnnamedBitfield())
983 ++InitializableMembers;
984
985 if (structDecl->isUnion())
986 return std::min(InitializableMembers, 1);
987 return InitializableMembers - structDecl->hasFlexibleArrayMember();
988 }
989
990 /// Determine whether Entity is an entity for which it is idiomatic to elide
991 /// the braces in aggregate initialization.
isIdiomaticBraceElisionEntity(const InitializedEntity & Entity)992 static bool isIdiomaticBraceElisionEntity(const InitializedEntity &Entity) {
993 // Recursive initialization of the one and only field within an aggregate
994 // class is considered idiomatic. This case arises in particular for
995 // initialization of std::array, where the C++ standard suggests the idiom of
996 //
997 // std::array<T, N> arr = {1, 2, 3};
998 //
999 // (where std::array is an aggregate struct containing a single array field.
1000
1001 // FIXME: Should aggregate initialization of a struct with a single
1002 // base class and no members also suppress the warning?
1003 if (Entity.getKind() != InitializedEntity::EK_Member || !Entity.getParent())
1004 return false;
1005
1006 auto *ParentRD =
1007 Entity.getParent()->getType()->castAs<RecordType>()->getDecl();
1008 if (CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(ParentRD))
1009 if (CXXRD->getNumBases())
1010 return false;
1011
1012 auto FieldIt = ParentRD->field_begin();
1013 assert(FieldIt != ParentRD->field_end() &&
1014 "no fields but have initializer for member?");
1015 return ++FieldIt == ParentRD->field_end();
1016 }
1017
1018 /// Check whether the range of the initializer \p ParentIList from element
1019 /// \p Index onwards can be used to initialize an object of type \p T. Update
1020 /// \p Index to indicate how many elements of the list were consumed.
1021 ///
1022 /// This also fills in \p StructuredList, from element \p StructuredIndex
1023 /// onwards, with the fully-braced, desugared form of the initialization.
CheckImplicitInitList(const InitializedEntity & Entity,InitListExpr * ParentIList,QualType T,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1024 void InitListChecker::CheckImplicitInitList(const InitializedEntity &Entity,
1025 InitListExpr *ParentIList,
1026 QualType T, unsigned &Index,
1027 InitListExpr *StructuredList,
1028 unsigned &StructuredIndex) {
1029 int maxElements = 0;
1030
1031 if (T->isArrayType())
1032 maxElements = numArrayElements(T);
1033 else if (T->isRecordType())
1034 maxElements = numStructUnionElements(T);
1035 else if (T->isVectorType())
1036 maxElements = T->castAs<VectorType>()->getNumElements();
1037 else
1038 llvm_unreachable("CheckImplicitInitList(): Illegal type");
1039
1040 if (maxElements == 0) {
1041 if (!VerifyOnly)
1042 SemaRef.Diag(ParentIList->getInit(Index)->getBeginLoc(),
1043 diag::err_implicit_empty_initializer);
1044 ++Index;
1045 hadError = true;
1046 return;
1047 }
1048
1049 // Build a structured initializer list corresponding to this subobject.
1050 InitListExpr *StructuredSubobjectInitList = getStructuredSubobjectInit(
1051 ParentIList, Index, T, StructuredList, StructuredIndex,
1052 SourceRange(ParentIList->getInit(Index)->getBeginLoc(),
1053 ParentIList->getSourceRange().getEnd()));
1054 unsigned StructuredSubobjectInitIndex = 0;
1055
1056 // Check the element types and build the structural subobject.
1057 unsigned StartIndex = Index;
1058 CheckListElementTypes(Entity, ParentIList, T,
1059 /*SubobjectIsDesignatorContext=*/false, Index,
1060 StructuredSubobjectInitList,
1061 StructuredSubobjectInitIndex);
1062
1063 if (StructuredSubobjectInitList) {
1064 StructuredSubobjectInitList->setType(T);
1065
1066 unsigned EndIndex = (Index == StartIndex? StartIndex : Index - 1);
1067 // Update the structured sub-object initializer so that it's ending
1068 // range corresponds with the end of the last initializer it used.
1069 if (EndIndex < ParentIList->getNumInits() &&
1070 ParentIList->getInit(EndIndex)) {
1071 SourceLocation EndLoc
1072 = ParentIList->getInit(EndIndex)->getSourceRange().getEnd();
1073 StructuredSubobjectInitList->setRBraceLoc(EndLoc);
1074 }
1075
1076 // Complain about missing braces.
1077 if (!VerifyOnly && (T->isArrayType() || T->isRecordType()) &&
1078 !ParentIList->isIdiomaticZeroInitializer(SemaRef.getLangOpts()) &&
1079 !isIdiomaticBraceElisionEntity(Entity)) {
1080 SemaRef.Diag(StructuredSubobjectInitList->getBeginLoc(),
1081 diag::warn_missing_braces)
1082 << StructuredSubobjectInitList->getSourceRange()
1083 << FixItHint::CreateInsertion(
1084 StructuredSubobjectInitList->getBeginLoc(), "{")
1085 << FixItHint::CreateInsertion(
1086 SemaRef.getLocForEndOfToken(
1087 StructuredSubobjectInitList->getEndLoc()),
1088 "}");
1089 }
1090
1091 // Warn if this type won't be an aggregate in future versions of C++.
1092 auto *CXXRD = T->getAsCXXRecordDecl();
1093 if (!VerifyOnly && CXXRD && CXXRD->hasUserDeclaredConstructor()) {
1094 SemaRef.Diag(StructuredSubobjectInitList->getBeginLoc(),
1095 diag::warn_cxx2a_compat_aggregate_init_with_ctors)
1096 << StructuredSubobjectInitList->getSourceRange() << T;
1097 }
1098 }
1099 }
1100
1101 /// Warn that \p Entity was of scalar type and was initialized by a
1102 /// single-element braced initializer list.
warnBracedScalarInit(Sema & S,const InitializedEntity & Entity,SourceRange Braces)1103 static void warnBracedScalarInit(Sema &S, const InitializedEntity &Entity,
1104 SourceRange Braces) {
1105 // Don't warn during template instantiation. If the initialization was
1106 // non-dependent, we warned during the initial parse; otherwise, the
1107 // type might not be scalar in some uses of the template.
1108 if (S.inTemplateInstantiation())
1109 return;
1110
1111 unsigned DiagID = 0;
1112
1113 switch (Entity.getKind()) {
1114 case InitializedEntity::EK_VectorElement:
1115 case InitializedEntity::EK_ComplexElement:
1116 case InitializedEntity::EK_ArrayElement:
1117 case InitializedEntity::EK_Parameter:
1118 case InitializedEntity::EK_Parameter_CF_Audited:
1119 case InitializedEntity::EK_Result:
1120 // Extra braces here are suspicious.
1121 DiagID = diag::warn_braces_around_scalar_init;
1122 break;
1123
1124 case InitializedEntity::EK_Member:
1125 // Warn on aggregate initialization but not on ctor init list or
1126 // default member initializer.
1127 if (Entity.getParent())
1128 DiagID = diag::warn_braces_around_scalar_init;
1129 break;
1130
1131 case InitializedEntity::EK_Variable:
1132 case InitializedEntity::EK_LambdaCapture:
1133 // No warning, might be direct-list-initialization.
1134 // FIXME: Should we warn for copy-list-initialization in these cases?
1135 break;
1136
1137 case InitializedEntity::EK_New:
1138 case InitializedEntity::EK_Temporary:
1139 case InitializedEntity::EK_CompoundLiteralInit:
1140 // No warning, braces are part of the syntax of the underlying construct.
1141 break;
1142
1143 case InitializedEntity::EK_RelatedResult:
1144 // No warning, we already warned when initializing the result.
1145 break;
1146
1147 case InitializedEntity::EK_Exception:
1148 case InitializedEntity::EK_Base:
1149 case InitializedEntity::EK_Delegating:
1150 case InitializedEntity::EK_BlockElement:
1151 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
1152 case InitializedEntity::EK_Binding:
1153 case InitializedEntity::EK_StmtExprResult:
1154 llvm_unreachable("unexpected braced scalar init");
1155 }
1156
1157 if (DiagID) {
1158 S.Diag(Braces.getBegin(), DiagID)
1159 << Braces
1160 << FixItHint::CreateRemoval(Braces.getBegin())
1161 << FixItHint::CreateRemoval(Braces.getEnd());
1162 }
1163 }
1164
1165 /// Check whether the initializer \p IList (that was written with explicit
1166 /// braces) can be used to initialize an object of type \p T.
1167 ///
1168 /// This also fills in \p StructuredList with the fully-braced, desugared
1169 /// form of the initialization.
CheckExplicitInitList(const InitializedEntity & Entity,InitListExpr * IList,QualType & T,InitListExpr * StructuredList,bool TopLevelObject)1170 void InitListChecker::CheckExplicitInitList(const InitializedEntity &Entity,
1171 InitListExpr *IList, QualType &T,
1172 InitListExpr *StructuredList,
1173 bool TopLevelObject) {
1174 unsigned Index = 0, StructuredIndex = 0;
1175 CheckListElementTypes(Entity, IList, T, /*SubobjectIsDesignatorContext=*/true,
1176 Index, StructuredList, StructuredIndex, TopLevelObject);
1177 if (StructuredList) {
1178 QualType ExprTy = T;
1179 if (!ExprTy->isArrayType())
1180 ExprTy = ExprTy.getNonLValueExprType(SemaRef.Context);
1181 if (!VerifyOnly)
1182 IList->setType(ExprTy);
1183 StructuredList->setType(ExprTy);
1184 }
1185 if (hadError)
1186 return;
1187
1188 // Don't complain for incomplete types, since we'll get an error elsewhere.
1189 if (Index < IList->getNumInits() && !T->isIncompleteType()) {
1190 // We have leftover initializers
1191 bool ExtraInitsIsError = SemaRef.getLangOpts().CPlusPlus ||
1192 (SemaRef.getLangOpts().OpenCL && T->isVectorType());
1193 hadError = ExtraInitsIsError;
1194 if (VerifyOnly) {
1195 return;
1196 } else if (StructuredIndex == 1 &&
1197 IsStringInit(StructuredList->getInit(0), T, SemaRef.Context) ==
1198 SIF_None) {
1199 unsigned DK =
1200 ExtraInitsIsError
1201 ? diag::err_excess_initializers_in_char_array_initializer
1202 : diag::ext_excess_initializers_in_char_array_initializer;
1203 SemaRef.Diag(IList->getInit(Index)->getBeginLoc(), DK)
1204 << IList->getInit(Index)->getSourceRange();
1205 } else {
1206 int initKind = T->isArrayType() ? 0 :
1207 T->isVectorType() ? 1 :
1208 T->isScalarType() ? 2 :
1209 T->isUnionType() ? 3 :
1210 4;
1211
1212 unsigned DK = ExtraInitsIsError ? diag::err_excess_initializers
1213 : diag::ext_excess_initializers;
1214 SemaRef.Diag(IList->getInit(Index)->getBeginLoc(), DK)
1215 << initKind << IList->getInit(Index)->getSourceRange();
1216 }
1217 }
1218
1219 if (!VerifyOnly) {
1220 if (T->isScalarType() && IList->getNumInits() == 1 &&
1221 !isa<InitListExpr>(IList->getInit(0)))
1222 warnBracedScalarInit(SemaRef, Entity, IList->getSourceRange());
1223
1224 // Warn if this is a class type that won't be an aggregate in future
1225 // versions of C++.
1226 auto *CXXRD = T->getAsCXXRecordDecl();
1227 if (CXXRD && CXXRD->hasUserDeclaredConstructor()) {
1228 // Don't warn if there's an equivalent default constructor that would be
1229 // used instead.
1230 bool HasEquivCtor = false;
1231 if (IList->getNumInits() == 0) {
1232 auto *CD = SemaRef.LookupDefaultConstructor(CXXRD);
1233 HasEquivCtor = CD && !CD->isDeleted();
1234 }
1235
1236 if (!HasEquivCtor) {
1237 SemaRef.Diag(IList->getBeginLoc(),
1238 diag::warn_cxx2a_compat_aggregate_init_with_ctors)
1239 << IList->getSourceRange() << T;
1240 }
1241 }
1242 }
1243 }
1244
CheckListElementTypes(const InitializedEntity & Entity,InitListExpr * IList,QualType & DeclType,bool SubobjectIsDesignatorContext,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex,bool TopLevelObject)1245 void InitListChecker::CheckListElementTypes(const InitializedEntity &Entity,
1246 InitListExpr *IList,
1247 QualType &DeclType,
1248 bool SubobjectIsDesignatorContext,
1249 unsigned &Index,
1250 InitListExpr *StructuredList,
1251 unsigned &StructuredIndex,
1252 bool TopLevelObject) {
1253 if (DeclType->isAnyComplexType() && SubobjectIsDesignatorContext) {
1254 // Explicitly braced initializer for complex type can be real+imaginary
1255 // parts.
1256 CheckComplexType(Entity, IList, DeclType, Index,
1257 StructuredList, StructuredIndex);
1258 } else if (DeclType->isScalarType()) {
1259 CheckScalarType(Entity, IList, DeclType, Index,
1260 StructuredList, StructuredIndex);
1261 } else if (DeclType->isVectorType()) {
1262 CheckVectorType(Entity, IList, DeclType, Index,
1263 StructuredList, StructuredIndex);
1264 } else if (DeclType->isRecordType()) {
1265 assert(DeclType->isAggregateType() &&
1266 "non-aggregate records should be handed in CheckSubElementType");
1267 RecordDecl *RD = DeclType->castAs<RecordType>()->getDecl();
1268 auto Bases =
1269 CXXRecordDecl::base_class_range(CXXRecordDecl::base_class_iterator(),
1270 CXXRecordDecl::base_class_iterator());
1271 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
1272 Bases = CXXRD->bases();
1273 CheckStructUnionTypes(Entity, IList, DeclType, Bases, RD->field_begin(),
1274 SubobjectIsDesignatorContext, Index, StructuredList,
1275 StructuredIndex, TopLevelObject);
1276 } else if (DeclType->isArrayType()) {
1277 llvm::APSInt Zero(
1278 SemaRef.Context.getTypeSize(SemaRef.Context.getSizeType()),
1279 false);
1280 CheckArrayType(Entity, IList, DeclType, Zero,
1281 SubobjectIsDesignatorContext, Index,
1282 StructuredList, StructuredIndex);
1283 } else if (DeclType->isVoidType() || DeclType->isFunctionType()) {
1284 // This type is invalid, issue a diagnostic.
1285 ++Index;
1286 if (!VerifyOnly)
1287 SemaRef.Diag(IList->getBeginLoc(), diag::err_illegal_initializer_type)
1288 << DeclType;
1289 hadError = true;
1290 } else if (DeclType->isReferenceType()) {
1291 CheckReferenceType(Entity, IList, DeclType, Index,
1292 StructuredList, StructuredIndex);
1293 } else if (DeclType->isObjCObjectType()) {
1294 if (!VerifyOnly)
1295 SemaRef.Diag(IList->getBeginLoc(), diag::err_init_objc_class) << DeclType;
1296 hadError = true;
1297 } else if (DeclType->isOCLIntelSubgroupAVCType()) {
1298 // Checks for scalar type are sufficient for these types too.
1299 CheckScalarType(Entity, IList, DeclType, Index, StructuredList,
1300 StructuredIndex);
1301 } else {
1302 if (!VerifyOnly)
1303 SemaRef.Diag(IList->getBeginLoc(), diag::err_illegal_initializer_type)
1304 << DeclType;
1305 hadError = true;
1306 }
1307 }
1308
CheckSubElementType(const InitializedEntity & Entity,InitListExpr * IList,QualType ElemType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1309 void InitListChecker::CheckSubElementType(const InitializedEntity &Entity,
1310 InitListExpr *IList,
1311 QualType ElemType,
1312 unsigned &Index,
1313 InitListExpr *StructuredList,
1314 unsigned &StructuredIndex) {
1315 Expr *expr = IList->getInit(Index);
1316
1317 if (ElemType->isReferenceType())
1318 return CheckReferenceType(Entity, IList, ElemType, Index,
1319 StructuredList, StructuredIndex);
1320
1321 if (InitListExpr *SubInitList = dyn_cast<InitListExpr>(expr)) {
1322 if (SubInitList->getNumInits() == 1 &&
1323 IsStringInit(SubInitList->getInit(0), ElemType, SemaRef.Context) ==
1324 SIF_None) {
1325 // FIXME: It would be more faithful and no less correct to include an
1326 // InitListExpr in the semantic form of the initializer list in this case.
1327 expr = SubInitList->getInit(0);
1328 }
1329 // Nested aggregate initialization and C++ initialization are handled later.
1330 } else if (isa<ImplicitValueInitExpr>(expr)) {
1331 // This happens during template instantiation when we see an InitListExpr
1332 // that we've already checked once.
1333 assert(SemaRef.Context.hasSameType(expr->getType(), ElemType) &&
1334 "found implicit initialization for the wrong type");
1335 UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
1336 ++Index;
1337 return;
1338 }
1339
1340 if (SemaRef.getLangOpts().CPlusPlus || isa<InitListExpr>(expr)) {
1341 // C++ [dcl.init.aggr]p2:
1342 // Each member is copy-initialized from the corresponding
1343 // initializer-clause.
1344
1345 // FIXME: Better EqualLoc?
1346 InitializationKind Kind =
1347 InitializationKind::CreateCopy(expr->getBeginLoc(), SourceLocation());
1348
1349 // Vector elements can be initialized from other vectors in which case
1350 // we need initialization entity with a type of a vector (and not a vector
1351 // element!) initializing multiple vector elements.
1352 auto TmpEntity =
1353 (ElemType->isExtVectorType() && !Entity.getType()->isExtVectorType())
1354 ? InitializedEntity::InitializeTemporary(ElemType)
1355 : Entity;
1356
1357 InitializationSequence Seq(SemaRef, TmpEntity, Kind, expr,
1358 /*TopLevelOfInitList*/ true);
1359
1360 // C++14 [dcl.init.aggr]p13:
1361 // If the assignment-expression can initialize a member, the member is
1362 // initialized. Otherwise [...] brace elision is assumed
1363 //
1364 // Brace elision is never performed if the element is not an
1365 // assignment-expression.
1366 if (Seq || isa<InitListExpr>(expr)) {
1367 if (!VerifyOnly) {
1368 ExprResult Result = Seq.Perform(SemaRef, TmpEntity, Kind, expr);
1369 if (Result.isInvalid())
1370 hadError = true;
1371
1372 UpdateStructuredListElement(StructuredList, StructuredIndex,
1373 Result.getAs<Expr>());
1374 } else if (!Seq) {
1375 hadError = true;
1376 } else if (StructuredList) {
1377 UpdateStructuredListElement(StructuredList, StructuredIndex,
1378 getDummyInit());
1379 }
1380 ++Index;
1381 return;
1382 }
1383
1384 // Fall through for subaggregate initialization
1385 } else if (ElemType->isScalarType() || ElemType->isAtomicType()) {
1386 // FIXME: Need to handle atomic aggregate types with implicit init lists.
1387 return CheckScalarType(Entity, IList, ElemType, Index,
1388 StructuredList, StructuredIndex);
1389 } else if (const ArrayType *arrayType =
1390 SemaRef.Context.getAsArrayType(ElemType)) {
1391 // arrayType can be incomplete if we're initializing a flexible
1392 // array member. There's nothing we can do with the completed
1393 // type here, though.
1394
1395 if (IsStringInit(expr, arrayType, SemaRef.Context) == SIF_None) {
1396 // FIXME: Should we do this checking in verify-only mode?
1397 if (!VerifyOnly)
1398 CheckStringInit(expr, ElemType, arrayType, SemaRef);
1399 if (StructuredList)
1400 UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
1401 ++Index;
1402 return;
1403 }
1404
1405 // Fall through for subaggregate initialization.
1406
1407 } else {
1408 assert((ElemType->isRecordType() || ElemType->isVectorType() ||
1409 ElemType->isOpenCLSpecificType()) && "Unexpected type");
1410
1411 // C99 6.7.8p13:
1412 //
1413 // The initializer for a structure or union object that has
1414 // automatic storage duration shall be either an initializer
1415 // list as described below, or a single expression that has
1416 // compatible structure or union type. In the latter case, the
1417 // initial value of the object, including unnamed members, is
1418 // that of the expression.
1419 ExprResult ExprRes = expr;
1420 if (SemaRef.CheckSingleAssignmentConstraints(
1421 ElemType, ExprRes, !VerifyOnly) != Sema::Incompatible) {
1422 if (ExprRes.isInvalid())
1423 hadError = true;
1424 else {
1425 ExprRes = SemaRef.DefaultFunctionArrayLvalueConversion(ExprRes.get());
1426 if (ExprRes.isInvalid())
1427 hadError = true;
1428 }
1429 UpdateStructuredListElement(StructuredList, StructuredIndex,
1430 ExprRes.getAs<Expr>());
1431 ++Index;
1432 return;
1433 }
1434 ExprRes.get();
1435 // Fall through for subaggregate initialization
1436 }
1437
1438 // C++ [dcl.init.aggr]p12:
1439 //
1440 // [...] Otherwise, if the member is itself a non-empty
1441 // subaggregate, brace elision is assumed and the initializer is
1442 // considered for the initialization of the first member of
1443 // the subaggregate.
1444 // OpenCL vector initializer is handled elsewhere.
1445 if ((!SemaRef.getLangOpts().OpenCL && ElemType->isVectorType()) ||
1446 ElemType->isAggregateType()) {
1447 CheckImplicitInitList(Entity, IList, ElemType, Index, StructuredList,
1448 StructuredIndex);
1449 ++StructuredIndex;
1450 } else {
1451 if (!VerifyOnly) {
1452 // We cannot initialize this element, so let PerformCopyInitialization
1453 // produce the appropriate diagnostic. We already checked that this
1454 // initialization will fail.
1455 ExprResult Copy =
1456 SemaRef.PerformCopyInitialization(Entity, SourceLocation(), expr,
1457 /*TopLevelOfInitList=*/true);
1458 (void)Copy;
1459 assert(Copy.isInvalid() &&
1460 "expected non-aggregate initialization to fail");
1461 }
1462 hadError = true;
1463 ++Index;
1464 ++StructuredIndex;
1465 }
1466 }
1467
CheckComplexType(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1468 void InitListChecker::CheckComplexType(const InitializedEntity &Entity,
1469 InitListExpr *IList, QualType DeclType,
1470 unsigned &Index,
1471 InitListExpr *StructuredList,
1472 unsigned &StructuredIndex) {
1473 assert(Index == 0 && "Index in explicit init list must be zero");
1474
1475 // As an extension, clang supports complex initializers, which initialize
1476 // a complex number component-wise. When an explicit initializer list for
1477 // a complex number contains two two initializers, this extension kicks in:
1478 // it exepcts the initializer list to contain two elements convertible to
1479 // the element type of the complex type. The first element initializes
1480 // the real part, and the second element intitializes the imaginary part.
1481
1482 if (IList->getNumInits() != 2)
1483 return CheckScalarType(Entity, IList, DeclType, Index, StructuredList,
1484 StructuredIndex);
1485
1486 // This is an extension in C. (The builtin _Complex type does not exist
1487 // in the C++ standard.)
1488 if (!SemaRef.getLangOpts().CPlusPlus && !VerifyOnly)
1489 SemaRef.Diag(IList->getBeginLoc(), diag::ext_complex_component_init)
1490 << IList->getSourceRange();
1491
1492 // Initialize the complex number.
1493 QualType elementType = DeclType->castAs<ComplexType>()->getElementType();
1494 InitializedEntity ElementEntity =
1495 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
1496
1497 for (unsigned i = 0; i < 2; ++i) {
1498 ElementEntity.setElementIndex(Index);
1499 CheckSubElementType(ElementEntity, IList, elementType, Index,
1500 StructuredList, StructuredIndex);
1501 }
1502 }
1503
CheckScalarType(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1504 void InitListChecker::CheckScalarType(const InitializedEntity &Entity,
1505 InitListExpr *IList, QualType DeclType,
1506 unsigned &Index,
1507 InitListExpr *StructuredList,
1508 unsigned &StructuredIndex) {
1509 if (Index >= IList->getNumInits()) {
1510 if (!VerifyOnly)
1511 SemaRef.Diag(IList->getBeginLoc(),
1512 SemaRef.getLangOpts().CPlusPlus11
1513 ? diag::warn_cxx98_compat_empty_scalar_initializer
1514 : diag::err_empty_scalar_initializer)
1515 << IList->getSourceRange();
1516 hadError = !SemaRef.getLangOpts().CPlusPlus11;
1517 ++Index;
1518 ++StructuredIndex;
1519 return;
1520 }
1521
1522 Expr *expr = IList->getInit(Index);
1523 if (InitListExpr *SubIList = dyn_cast<InitListExpr>(expr)) {
1524 // FIXME: This is invalid, and accepting it causes overload resolution
1525 // to pick the wrong overload in some corner cases.
1526 if (!VerifyOnly)
1527 SemaRef.Diag(SubIList->getBeginLoc(),
1528 diag::ext_many_braces_around_scalar_init)
1529 << SubIList->getSourceRange();
1530
1531 CheckScalarType(Entity, SubIList, DeclType, Index, StructuredList,
1532 StructuredIndex);
1533 return;
1534 } else if (isa<DesignatedInitExpr>(expr)) {
1535 if (!VerifyOnly)
1536 SemaRef.Diag(expr->getBeginLoc(), diag::err_designator_for_scalar_init)
1537 << DeclType << expr->getSourceRange();
1538 hadError = true;
1539 ++Index;
1540 ++StructuredIndex;
1541 return;
1542 }
1543
1544 ExprResult Result;
1545 if (VerifyOnly) {
1546 if (SemaRef.CanPerformCopyInitialization(Entity, expr))
1547 Result = getDummyInit();
1548 else
1549 Result = ExprError();
1550 } else {
1551 Result =
1552 SemaRef.PerformCopyInitialization(Entity, expr->getBeginLoc(), expr,
1553 /*TopLevelOfInitList=*/true);
1554 }
1555
1556 Expr *ResultExpr = nullptr;
1557
1558 if (Result.isInvalid())
1559 hadError = true; // types weren't compatible.
1560 else {
1561 ResultExpr = Result.getAs<Expr>();
1562
1563 if (ResultExpr != expr && !VerifyOnly) {
1564 // The type was promoted, update initializer list.
1565 // FIXME: Why are we updating the syntactic init list?
1566 IList->setInit(Index, ResultExpr);
1567 }
1568 }
1569 if (hadError)
1570 ++StructuredIndex;
1571 else
1572 UpdateStructuredListElement(StructuredList, StructuredIndex, ResultExpr);
1573 ++Index;
1574 }
1575
CheckReferenceType(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1576 void InitListChecker::CheckReferenceType(const InitializedEntity &Entity,
1577 InitListExpr *IList, QualType DeclType,
1578 unsigned &Index,
1579 InitListExpr *StructuredList,
1580 unsigned &StructuredIndex) {
1581 if (Index >= IList->getNumInits()) {
1582 // FIXME: It would be wonderful if we could point at the actual member. In
1583 // general, it would be useful to pass location information down the stack,
1584 // so that we know the location (or decl) of the "current object" being
1585 // initialized.
1586 if (!VerifyOnly)
1587 SemaRef.Diag(IList->getBeginLoc(),
1588 diag::err_init_reference_member_uninitialized)
1589 << DeclType << IList->getSourceRange();
1590 hadError = true;
1591 ++Index;
1592 ++StructuredIndex;
1593 return;
1594 }
1595
1596 Expr *expr = IList->getInit(Index);
1597 if (isa<InitListExpr>(expr) && !SemaRef.getLangOpts().CPlusPlus11) {
1598 if (!VerifyOnly)
1599 SemaRef.Diag(IList->getBeginLoc(), diag::err_init_non_aggr_init_list)
1600 << DeclType << IList->getSourceRange();
1601 hadError = true;
1602 ++Index;
1603 ++StructuredIndex;
1604 return;
1605 }
1606
1607 ExprResult Result;
1608 if (VerifyOnly) {
1609 if (SemaRef.CanPerformCopyInitialization(Entity,expr))
1610 Result = getDummyInit();
1611 else
1612 Result = ExprError();
1613 } else {
1614 Result =
1615 SemaRef.PerformCopyInitialization(Entity, expr->getBeginLoc(), expr,
1616 /*TopLevelOfInitList=*/true);
1617 }
1618
1619 if (Result.isInvalid())
1620 hadError = true;
1621
1622 expr = Result.getAs<Expr>();
1623 // FIXME: Why are we updating the syntactic init list?
1624 if (!VerifyOnly)
1625 IList->setInit(Index, expr);
1626
1627 if (hadError)
1628 ++StructuredIndex;
1629 else
1630 UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
1631 ++Index;
1632 }
1633
CheckVectorType(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1634 void InitListChecker::CheckVectorType(const InitializedEntity &Entity,
1635 InitListExpr *IList, QualType DeclType,
1636 unsigned &Index,
1637 InitListExpr *StructuredList,
1638 unsigned &StructuredIndex) {
1639 const VectorType *VT = DeclType->castAs<VectorType>();
1640 unsigned maxElements = VT->getNumElements();
1641 unsigned numEltsInit = 0;
1642 QualType elementType = VT->getElementType();
1643
1644 if (Index >= IList->getNumInits()) {
1645 // Make sure the element type can be value-initialized.
1646 CheckEmptyInitializable(
1647 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity),
1648 IList->getEndLoc());
1649 return;
1650 }
1651
1652 if (!SemaRef.getLangOpts().OpenCL) {
1653 // If the initializing element is a vector, try to copy-initialize
1654 // instead of breaking it apart (which is doomed to failure anyway).
1655 Expr *Init = IList->getInit(Index);
1656 if (!isa<InitListExpr>(Init) && Init->getType()->isVectorType()) {
1657 ExprResult Result;
1658 if (VerifyOnly) {
1659 if (SemaRef.CanPerformCopyInitialization(Entity, Init))
1660 Result = getDummyInit();
1661 else
1662 Result = ExprError();
1663 } else {
1664 Result =
1665 SemaRef.PerformCopyInitialization(Entity, Init->getBeginLoc(), Init,
1666 /*TopLevelOfInitList=*/true);
1667 }
1668
1669 Expr *ResultExpr = nullptr;
1670 if (Result.isInvalid())
1671 hadError = true; // types weren't compatible.
1672 else {
1673 ResultExpr = Result.getAs<Expr>();
1674
1675 if (ResultExpr != Init && !VerifyOnly) {
1676 // The type was promoted, update initializer list.
1677 // FIXME: Why are we updating the syntactic init list?
1678 IList->setInit(Index, ResultExpr);
1679 }
1680 }
1681 if (hadError)
1682 ++StructuredIndex;
1683 else
1684 UpdateStructuredListElement(StructuredList, StructuredIndex,
1685 ResultExpr);
1686 ++Index;
1687 return;
1688 }
1689
1690 InitializedEntity ElementEntity =
1691 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
1692
1693 for (unsigned i = 0; i < maxElements; ++i, ++numEltsInit) {
1694 // Don't attempt to go past the end of the init list
1695 if (Index >= IList->getNumInits()) {
1696 CheckEmptyInitializable(ElementEntity, IList->getEndLoc());
1697 break;
1698 }
1699
1700 ElementEntity.setElementIndex(Index);
1701 CheckSubElementType(ElementEntity, IList, elementType, Index,
1702 StructuredList, StructuredIndex);
1703 }
1704
1705 if (VerifyOnly)
1706 return;
1707
1708 bool isBigEndian = SemaRef.Context.getTargetInfo().isBigEndian();
1709 const VectorType *T = Entity.getType()->castAs<VectorType>();
1710 if (isBigEndian && (T->getVectorKind() == VectorType::NeonVector ||
1711 T->getVectorKind() == VectorType::NeonPolyVector)) {
1712 // The ability to use vector initializer lists is a GNU vector extension
1713 // and is unrelated to the NEON intrinsics in arm_neon.h. On little
1714 // endian machines it works fine, however on big endian machines it
1715 // exhibits surprising behaviour:
1716 //
1717 // uint32x2_t x = {42, 64};
1718 // return vget_lane_u32(x, 0); // Will return 64.
1719 //
1720 // Because of this, explicitly call out that it is non-portable.
1721 //
1722 SemaRef.Diag(IList->getBeginLoc(),
1723 diag::warn_neon_vector_initializer_non_portable);
1724
1725 const char *typeCode;
1726 unsigned typeSize = SemaRef.Context.getTypeSize(elementType);
1727
1728 if (elementType->isFloatingType())
1729 typeCode = "f";
1730 else if (elementType->isSignedIntegerType())
1731 typeCode = "s";
1732 else if (elementType->isUnsignedIntegerType())
1733 typeCode = "u";
1734 else
1735 llvm_unreachable("Invalid element type!");
1736
1737 SemaRef.Diag(IList->getBeginLoc(),
1738 SemaRef.Context.getTypeSize(VT) > 64
1739 ? diag::note_neon_vector_initializer_non_portable_q
1740 : diag::note_neon_vector_initializer_non_portable)
1741 << typeCode << typeSize;
1742 }
1743
1744 return;
1745 }
1746
1747 InitializedEntity ElementEntity =
1748 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
1749
1750 // OpenCL initializers allows vectors to be constructed from vectors.
1751 for (unsigned i = 0; i < maxElements; ++i) {
1752 // Don't attempt to go past the end of the init list
1753 if (Index >= IList->getNumInits())
1754 break;
1755
1756 ElementEntity.setElementIndex(Index);
1757
1758 QualType IType = IList->getInit(Index)->getType();
1759 if (!IType->isVectorType()) {
1760 CheckSubElementType(ElementEntity, IList, elementType, Index,
1761 StructuredList, StructuredIndex);
1762 ++numEltsInit;
1763 } else {
1764 QualType VecType;
1765 const VectorType *IVT = IType->castAs<VectorType>();
1766 unsigned numIElts = IVT->getNumElements();
1767
1768 if (IType->isExtVectorType())
1769 VecType = SemaRef.Context.getExtVectorType(elementType, numIElts);
1770 else
1771 VecType = SemaRef.Context.getVectorType(elementType, numIElts,
1772 IVT->getVectorKind());
1773 CheckSubElementType(ElementEntity, IList, VecType, Index,
1774 StructuredList, StructuredIndex);
1775 numEltsInit += numIElts;
1776 }
1777 }
1778
1779 // OpenCL requires all elements to be initialized.
1780 if (numEltsInit != maxElements) {
1781 if (!VerifyOnly)
1782 SemaRef.Diag(IList->getBeginLoc(),
1783 diag::err_vector_incorrect_num_initializers)
1784 << (numEltsInit < maxElements) << maxElements << numEltsInit;
1785 hadError = true;
1786 }
1787 }
1788
1789 /// Check if the type of a class element has an accessible destructor, and marks
1790 /// it referenced. Returns true if we shouldn't form a reference to the
1791 /// destructor.
1792 ///
1793 /// Aggregate initialization requires a class element's destructor be
1794 /// accessible per 11.6.1 [dcl.init.aggr]:
1795 ///
1796 /// The destructor for each element of class type is potentially invoked
1797 /// (15.4 [class.dtor]) from the context where the aggregate initialization
1798 /// occurs.
checkDestructorReference(QualType ElementType,SourceLocation Loc,Sema & SemaRef)1799 static bool checkDestructorReference(QualType ElementType, SourceLocation Loc,
1800 Sema &SemaRef) {
1801 auto *CXXRD = ElementType->getAsCXXRecordDecl();
1802 if (!CXXRD)
1803 return false;
1804
1805 CXXDestructorDecl *Destructor = SemaRef.LookupDestructor(CXXRD);
1806 SemaRef.CheckDestructorAccess(Loc, Destructor,
1807 SemaRef.PDiag(diag::err_access_dtor_temp)
1808 << ElementType);
1809 SemaRef.MarkFunctionReferenced(Loc, Destructor);
1810 return SemaRef.DiagnoseUseOfDecl(Destructor, Loc);
1811 }
1812
CheckArrayType(const InitializedEntity & Entity,InitListExpr * IList,QualType & DeclType,llvm::APSInt elementIndex,bool SubobjectIsDesignatorContext,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1813 void InitListChecker::CheckArrayType(const InitializedEntity &Entity,
1814 InitListExpr *IList, QualType &DeclType,
1815 llvm::APSInt elementIndex,
1816 bool SubobjectIsDesignatorContext,
1817 unsigned &Index,
1818 InitListExpr *StructuredList,
1819 unsigned &StructuredIndex) {
1820 const ArrayType *arrayType = SemaRef.Context.getAsArrayType(DeclType);
1821
1822 if (!VerifyOnly) {
1823 if (checkDestructorReference(arrayType->getElementType(),
1824 IList->getEndLoc(), SemaRef)) {
1825 hadError = true;
1826 return;
1827 }
1828 }
1829
1830 // Check for the special-case of initializing an array with a string.
1831 if (Index < IList->getNumInits()) {
1832 if (IsStringInit(IList->getInit(Index), arrayType, SemaRef.Context) ==
1833 SIF_None) {
1834 // We place the string literal directly into the resulting
1835 // initializer list. This is the only place where the structure
1836 // of the structured initializer list doesn't match exactly,
1837 // because doing so would involve allocating one character
1838 // constant for each string.
1839 // FIXME: Should we do these checks in verify-only mode too?
1840 if (!VerifyOnly)
1841 CheckStringInit(IList->getInit(Index), DeclType, arrayType, SemaRef);
1842 if (StructuredList) {
1843 UpdateStructuredListElement(StructuredList, StructuredIndex,
1844 IList->getInit(Index));
1845 StructuredList->resizeInits(SemaRef.Context, StructuredIndex);
1846 }
1847 ++Index;
1848 return;
1849 }
1850 }
1851 if (const VariableArrayType *VAT = dyn_cast<VariableArrayType>(arrayType)) {
1852 // Check for VLAs; in standard C it would be possible to check this
1853 // earlier, but I don't know where clang accepts VLAs (gcc accepts
1854 // them in all sorts of strange places).
1855 if (!VerifyOnly)
1856 SemaRef.Diag(VAT->getSizeExpr()->getBeginLoc(),
1857 diag::err_variable_object_no_init)
1858 << VAT->getSizeExpr()->getSourceRange();
1859 hadError = true;
1860 ++Index;
1861 ++StructuredIndex;
1862 return;
1863 }
1864
1865 // We might know the maximum number of elements in advance.
1866 llvm::APSInt maxElements(elementIndex.getBitWidth(),
1867 elementIndex.isUnsigned());
1868 bool maxElementsKnown = false;
1869 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(arrayType)) {
1870 maxElements = CAT->getSize();
1871 elementIndex = elementIndex.extOrTrunc(maxElements.getBitWidth());
1872 elementIndex.setIsUnsigned(maxElements.isUnsigned());
1873 maxElementsKnown = true;
1874 }
1875
1876 QualType elementType = arrayType->getElementType();
1877 while (Index < IList->getNumInits()) {
1878 Expr *Init = IList->getInit(Index);
1879 if (DesignatedInitExpr *DIE = dyn_cast<DesignatedInitExpr>(Init)) {
1880 // If we're not the subobject that matches up with the '{' for
1881 // the designator, we shouldn't be handling the
1882 // designator. Return immediately.
1883 if (!SubobjectIsDesignatorContext)
1884 return;
1885
1886 // Handle this designated initializer. elementIndex will be
1887 // updated to be the next array element we'll initialize.
1888 if (CheckDesignatedInitializer(Entity, IList, DIE, 0,
1889 DeclType, nullptr, &elementIndex, Index,
1890 StructuredList, StructuredIndex, true,
1891 false)) {
1892 hadError = true;
1893 continue;
1894 }
1895
1896 if (elementIndex.getBitWidth() > maxElements.getBitWidth())
1897 maxElements = maxElements.extend(elementIndex.getBitWidth());
1898 else if (elementIndex.getBitWidth() < maxElements.getBitWidth())
1899 elementIndex = elementIndex.extend(maxElements.getBitWidth());
1900 elementIndex.setIsUnsigned(maxElements.isUnsigned());
1901
1902 // If the array is of incomplete type, keep track of the number of
1903 // elements in the initializer.
1904 if (!maxElementsKnown && elementIndex > maxElements)
1905 maxElements = elementIndex;
1906
1907 continue;
1908 }
1909
1910 // If we know the maximum number of elements, and we've already
1911 // hit it, stop consuming elements in the initializer list.
1912 if (maxElementsKnown && elementIndex == maxElements)
1913 break;
1914
1915 InitializedEntity ElementEntity =
1916 InitializedEntity::InitializeElement(SemaRef.Context, StructuredIndex,
1917 Entity);
1918 // Check this element.
1919 CheckSubElementType(ElementEntity, IList, elementType, Index,
1920 StructuredList, StructuredIndex);
1921 ++elementIndex;
1922
1923 // If the array is of incomplete type, keep track of the number of
1924 // elements in the initializer.
1925 if (!maxElementsKnown && elementIndex > maxElements)
1926 maxElements = elementIndex;
1927 }
1928 if (!hadError && DeclType->isIncompleteArrayType() && !VerifyOnly) {
1929 // If this is an incomplete array type, the actual type needs to
1930 // be calculated here.
1931 llvm::APSInt Zero(maxElements.getBitWidth(), maxElements.isUnsigned());
1932 if (maxElements == Zero && !Entity.isVariableLengthArrayNew()) {
1933 // Sizing an array implicitly to zero is not allowed by ISO C,
1934 // but is supported by GNU.
1935 SemaRef.Diag(IList->getBeginLoc(), diag::ext_typecheck_zero_array_size);
1936 }
1937
1938 DeclType = SemaRef.Context.getConstantArrayType(
1939 elementType, maxElements, nullptr, ArrayType::Normal, 0);
1940 }
1941 if (!hadError) {
1942 // If there are any members of the array that get value-initialized, check
1943 // that is possible. That happens if we know the bound and don't have
1944 // enough elements, or if we're performing an array new with an unknown
1945 // bound.
1946 if ((maxElementsKnown && elementIndex < maxElements) ||
1947 Entity.isVariableLengthArrayNew())
1948 CheckEmptyInitializable(
1949 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity),
1950 IList->getEndLoc());
1951 }
1952 }
1953
CheckFlexibleArrayInit(const InitializedEntity & Entity,Expr * InitExpr,FieldDecl * Field,bool TopLevelObject)1954 bool InitListChecker::CheckFlexibleArrayInit(const InitializedEntity &Entity,
1955 Expr *InitExpr,
1956 FieldDecl *Field,
1957 bool TopLevelObject) {
1958 // Handle GNU flexible array initializers.
1959 unsigned FlexArrayDiag;
1960 if (isa<InitListExpr>(InitExpr) &&
1961 cast<InitListExpr>(InitExpr)->getNumInits() == 0) {
1962 // Empty flexible array init always allowed as an extension
1963 FlexArrayDiag = diag::ext_flexible_array_init;
1964 } else if (SemaRef.getLangOpts().CPlusPlus) {
1965 // Disallow flexible array init in C++; it is not required for gcc
1966 // compatibility, and it needs work to IRGen correctly in general.
1967 FlexArrayDiag = diag::err_flexible_array_init;
1968 } else if (!TopLevelObject) {
1969 // Disallow flexible array init on non-top-level object
1970 FlexArrayDiag = diag::err_flexible_array_init;
1971 } else if (Entity.getKind() != InitializedEntity::EK_Variable) {
1972 // Disallow flexible array init on anything which is not a variable.
1973 FlexArrayDiag = diag::err_flexible_array_init;
1974 } else if (cast<VarDecl>(Entity.getDecl())->hasLocalStorage()) {
1975 // Disallow flexible array init on local variables.
1976 FlexArrayDiag = diag::err_flexible_array_init;
1977 } else {
1978 // Allow other cases.
1979 FlexArrayDiag = diag::ext_flexible_array_init;
1980 }
1981
1982 if (!VerifyOnly) {
1983 SemaRef.Diag(InitExpr->getBeginLoc(), FlexArrayDiag)
1984 << InitExpr->getBeginLoc();
1985 SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
1986 << Field;
1987 }
1988
1989 return FlexArrayDiag != diag::ext_flexible_array_init;
1990 }
1991
CheckStructUnionTypes(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,CXXRecordDecl::base_class_range Bases,RecordDecl::field_iterator Field,bool SubobjectIsDesignatorContext,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex,bool TopLevelObject)1992 void InitListChecker::CheckStructUnionTypes(
1993 const InitializedEntity &Entity, InitListExpr *IList, QualType DeclType,
1994 CXXRecordDecl::base_class_range Bases, RecordDecl::field_iterator Field,
1995 bool SubobjectIsDesignatorContext, unsigned &Index,
1996 InitListExpr *StructuredList, unsigned &StructuredIndex,
1997 bool TopLevelObject) {
1998 RecordDecl *structDecl = DeclType->castAs<RecordType>()->getDecl();
1999
2000 // If the record is invalid, some of it's members are invalid. To avoid
2001 // confusion, we forgo checking the intializer for the entire record.
2002 if (structDecl->isInvalidDecl()) {
2003 // Assume it was supposed to consume a single initializer.
2004 ++Index;
2005 hadError = true;
2006 return;
2007 }
2008
2009 if (DeclType->isUnionType() && IList->getNumInits() == 0) {
2010 RecordDecl *RD = DeclType->castAs<RecordType>()->getDecl();
2011
2012 if (!VerifyOnly)
2013 for (FieldDecl *FD : RD->fields()) {
2014 QualType ET = SemaRef.Context.getBaseElementType(FD->getType());
2015 if (checkDestructorReference(ET, IList->getEndLoc(), SemaRef)) {
2016 hadError = true;
2017 return;
2018 }
2019 }
2020
2021 // If there's a default initializer, use it.
2022 if (isa<CXXRecordDecl>(RD) &&
2023 cast<CXXRecordDecl>(RD)->hasInClassInitializer()) {
2024 if (!StructuredList)
2025 return;
2026 for (RecordDecl::field_iterator FieldEnd = RD->field_end();
2027 Field != FieldEnd; ++Field) {
2028 if (Field->hasInClassInitializer()) {
2029 StructuredList->setInitializedFieldInUnion(*Field);
2030 // FIXME: Actually build a CXXDefaultInitExpr?
2031 return;
2032 }
2033 }
2034 }
2035
2036 // Value-initialize the first member of the union that isn't an unnamed
2037 // bitfield.
2038 for (RecordDecl::field_iterator FieldEnd = RD->field_end();
2039 Field != FieldEnd; ++Field) {
2040 if (!Field->isUnnamedBitfield()) {
2041 CheckEmptyInitializable(
2042 InitializedEntity::InitializeMember(*Field, &Entity),
2043 IList->getEndLoc());
2044 if (StructuredList)
2045 StructuredList->setInitializedFieldInUnion(*Field);
2046 break;
2047 }
2048 }
2049 return;
2050 }
2051
2052 bool InitializedSomething = false;
2053
2054 // If we have any base classes, they are initialized prior to the fields.
2055 for (auto &Base : Bases) {
2056 Expr *Init = Index < IList->getNumInits() ? IList->getInit(Index) : nullptr;
2057
2058 // Designated inits always initialize fields, so if we see one, all
2059 // remaining base classes have no explicit initializer.
2060 if (Init && isa<DesignatedInitExpr>(Init))
2061 Init = nullptr;
2062
2063 SourceLocation InitLoc = Init ? Init->getBeginLoc() : IList->getEndLoc();
2064 InitializedEntity BaseEntity = InitializedEntity::InitializeBase(
2065 SemaRef.Context, &Base, false, &Entity);
2066 if (Init) {
2067 CheckSubElementType(BaseEntity, IList, Base.getType(), Index,
2068 StructuredList, StructuredIndex);
2069 InitializedSomething = true;
2070 } else {
2071 CheckEmptyInitializable(BaseEntity, InitLoc);
2072 }
2073
2074 if (!VerifyOnly)
2075 if (checkDestructorReference(Base.getType(), InitLoc, SemaRef)) {
2076 hadError = true;
2077 return;
2078 }
2079 }
2080
2081 // If structDecl is a forward declaration, this loop won't do
2082 // anything except look at designated initializers; That's okay,
2083 // because an error should get printed out elsewhere. It might be
2084 // worthwhile to skip over the rest of the initializer, though.
2085 RecordDecl *RD = DeclType->castAs<RecordType>()->getDecl();
2086 RecordDecl::field_iterator FieldEnd = RD->field_end();
2087 bool CheckForMissingFields =
2088 !IList->isIdiomaticZeroInitializer(SemaRef.getLangOpts());
2089 bool HasDesignatedInit = false;
2090
2091 while (Index < IList->getNumInits()) {
2092 Expr *Init = IList->getInit(Index);
2093 SourceLocation InitLoc = Init->getBeginLoc();
2094
2095 if (DesignatedInitExpr *DIE = dyn_cast<DesignatedInitExpr>(Init)) {
2096 // If we're not the subobject that matches up with the '{' for
2097 // the designator, we shouldn't be handling the
2098 // designator. Return immediately.
2099 if (!SubobjectIsDesignatorContext)
2100 return;
2101
2102 HasDesignatedInit = true;
2103
2104 // Handle this designated initializer. Field will be updated to
2105 // the next field that we'll be initializing.
2106 if (CheckDesignatedInitializer(Entity, IList, DIE, 0,
2107 DeclType, &Field, nullptr, Index,
2108 StructuredList, StructuredIndex,
2109 true, TopLevelObject))
2110 hadError = true;
2111 else if (!VerifyOnly) {
2112 // Find the field named by the designated initializer.
2113 RecordDecl::field_iterator F = RD->field_begin();
2114 while (std::next(F) != Field)
2115 ++F;
2116 QualType ET = SemaRef.Context.getBaseElementType(F->getType());
2117 if (checkDestructorReference(ET, InitLoc, SemaRef)) {
2118 hadError = true;
2119 return;
2120 }
2121 }
2122
2123 InitializedSomething = true;
2124
2125 // Disable check for missing fields when designators are used.
2126 // This matches gcc behaviour.
2127 CheckForMissingFields = false;
2128 continue;
2129 }
2130
2131 if (Field == FieldEnd) {
2132 // We've run out of fields. We're done.
2133 break;
2134 }
2135
2136 // We've already initialized a member of a union. We're done.
2137 if (InitializedSomething && DeclType->isUnionType())
2138 break;
2139
2140 // If we've hit the flexible array member at the end, we're done.
2141 if (Field->getType()->isIncompleteArrayType())
2142 break;
2143
2144 if (Field->isUnnamedBitfield()) {
2145 // Don't initialize unnamed bitfields, e.g. "int : 20;"
2146 ++Field;
2147 continue;
2148 }
2149
2150 // Make sure we can use this declaration.
2151 bool InvalidUse;
2152 if (VerifyOnly)
2153 InvalidUse = !SemaRef.CanUseDecl(*Field, TreatUnavailableAsInvalid);
2154 else
2155 InvalidUse = SemaRef.DiagnoseUseOfDecl(
2156 *Field, IList->getInit(Index)->getBeginLoc());
2157 if (InvalidUse) {
2158 ++Index;
2159 ++Field;
2160 hadError = true;
2161 continue;
2162 }
2163
2164 if (!VerifyOnly) {
2165 QualType ET = SemaRef.Context.getBaseElementType(Field->getType());
2166 if (checkDestructorReference(ET, InitLoc, SemaRef)) {
2167 hadError = true;
2168 return;
2169 }
2170 }
2171
2172 InitializedEntity MemberEntity =
2173 InitializedEntity::InitializeMember(*Field, &Entity);
2174 CheckSubElementType(MemberEntity, IList, Field->getType(), Index,
2175 StructuredList, StructuredIndex);
2176 InitializedSomething = true;
2177
2178 if (DeclType->isUnionType() && StructuredList) {
2179 // Initialize the first field within the union.
2180 StructuredList->setInitializedFieldInUnion(*Field);
2181 }
2182
2183 ++Field;
2184 }
2185
2186 // Emit warnings for missing struct field initializers.
2187 if (!VerifyOnly && InitializedSomething && CheckForMissingFields &&
2188 Field != FieldEnd && !Field->getType()->isIncompleteArrayType() &&
2189 !DeclType->isUnionType()) {
2190 // It is possible we have one or more unnamed bitfields remaining.
2191 // Find first (if any) named field and emit warning.
2192 for (RecordDecl::field_iterator it = Field, end = RD->field_end();
2193 it != end; ++it) {
2194 if (!it->isUnnamedBitfield() && !it->hasInClassInitializer()) {
2195 SemaRef.Diag(IList->getSourceRange().getEnd(),
2196 diag::warn_missing_field_initializers) << *it;
2197 break;
2198 }
2199 }
2200 }
2201
2202 // Check that any remaining fields can be value-initialized if we're not
2203 // building a structured list. (If we are, we'll check this later.)
2204 if (!StructuredList && Field != FieldEnd && !DeclType->isUnionType() &&
2205 !Field->getType()->isIncompleteArrayType()) {
2206 for (; Field != FieldEnd && !hadError; ++Field) {
2207 if (!Field->isUnnamedBitfield() && !Field->hasInClassInitializer())
2208 CheckEmptyInitializable(
2209 InitializedEntity::InitializeMember(*Field, &Entity),
2210 IList->getEndLoc());
2211 }
2212 }
2213
2214 // Check that the types of the remaining fields have accessible destructors.
2215 if (!VerifyOnly) {
2216 // If the initializer expression has a designated initializer, check the
2217 // elements for which a designated initializer is not provided too.
2218 RecordDecl::field_iterator I = HasDesignatedInit ? RD->field_begin()
2219 : Field;
2220 for (RecordDecl::field_iterator E = RD->field_end(); I != E; ++I) {
2221 QualType ET = SemaRef.Context.getBaseElementType(I->getType());
2222 if (checkDestructorReference(ET, IList->getEndLoc(), SemaRef)) {
2223 hadError = true;
2224 return;
2225 }
2226 }
2227 }
2228
2229 if (Field == FieldEnd || !Field->getType()->isIncompleteArrayType() ||
2230 Index >= IList->getNumInits())
2231 return;
2232
2233 if (CheckFlexibleArrayInit(Entity, IList->getInit(Index), *Field,
2234 TopLevelObject)) {
2235 hadError = true;
2236 ++Index;
2237 return;
2238 }
2239
2240 InitializedEntity MemberEntity =
2241 InitializedEntity::InitializeMember(*Field, &Entity);
2242
2243 if (isa<InitListExpr>(IList->getInit(Index)))
2244 CheckSubElementType(MemberEntity, IList, Field->getType(), Index,
2245 StructuredList, StructuredIndex);
2246 else
2247 CheckImplicitInitList(MemberEntity, IList, Field->getType(), Index,
2248 StructuredList, StructuredIndex);
2249 }
2250
2251 /// Expand a field designator that refers to a member of an
2252 /// anonymous struct or union into a series of field designators that
2253 /// refers to the field within the appropriate subobject.
2254 ///
ExpandAnonymousFieldDesignator(Sema & SemaRef,DesignatedInitExpr * DIE,unsigned DesigIdx,IndirectFieldDecl * IndirectField)2255 static void ExpandAnonymousFieldDesignator(Sema &SemaRef,
2256 DesignatedInitExpr *DIE,
2257 unsigned DesigIdx,
2258 IndirectFieldDecl *IndirectField) {
2259 typedef DesignatedInitExpr::Designator Designator;
2260
2261 // Build the replacement designators.
2262 SmallVector<Designator, 4> Replacements;
2263 for (IndirectFieldDecl::chain_iterator PI = IndirectField->chain_begin(),
2264 PE = IndirectField->chain_end(); PI != PE; ++PI) {
2265 if (PI + 1 == PE)
2266 Replacements.push_back(Designator((IdentifierInfo *)nullptr,
2267 DIE->getDesignator(DesigIdx)->getDotLoc(),
2268 DIE->getDesignator(DesigIdx)->getFieldLoc()));
2269 else
2270 Replacements.push_back(Designator((IdentifierInfo *)nullptr,
2271 SourceLocation(), SourceLocation()));
2272 assert(isa<FieldDecl>(*PI));
2273 Replacements.back().setField(cast<FieldDecl>(*PI));
2274 }
2275
2276 // Expand the current designator into the set of replacement
2277 // designators, so we have a full subobject path down to where the
2278 // member of the anonymous struct/union is actually stored.
2279 DIE->ExpandDesignator(SemaRef.Context, DesigIdx, &Replacements[0],
2280 &Replacements[0] + Replacements.size());
2281 }
2282
CloneDesignatedInitExpr(Sema & SemaRef,DesignatedInitExpr * DIE)2283 static DesignatedInitExpr *CloneDesignatedInitExpr(Sema &SemaRef,
2284 DesignatedInitExpr *DIE) {
2285 unsigned NumIndexExprs = DIE->getNumSubExprs() - 1;
2286 SmallVector<Expr*, 4> IndexExprs(NumIndexExprs);
2287 for (unsigned I = 0; I < NumIndexExprs; ++I)
2288 IndexExprs[I] = DIE->getSubExpr(I + 1);
2289 return DesignatedInitExpr::Create(SemaRef.Context, DIE->designators(),
2290 IndexExprs,
2291 DIE->getEqualOrColonLoc(),
2292 DIE->usesGNUSyntax(), DIE->getInit());
2293 }
2294
2295 namespace {
2296
2297 // Callback to only accept typo corrections that are for field members of
2298 // the given struct or union.
2299 class FieldInitializerValidatorCCC final : public CorrectionCandidateCallback {
2300 public:
FieldInitializerValidatorCCC(RecordDecl * RD)2301 explicit FieldInitializerValidatorCCC(RecordDecl *RD)
2302 : Record(RD) {}
2303
ValidateCandidate(const TypoCorrection & candidate)2304 bool ValidateCandidate(const TypoCorrection &candidate) override {
2305 FieldDecl *FD = candidate.getCorrectionDeclAs<FieldDecl>();
2306 return FD && FD->getDeclContext()->getRedeclContext()->Equals(Record);
2307 }
2308
clone()2309 std::unique_ptr<CorrectionCandidateCallback> clone() override {
2310 return std::make_unique<FieldInitializerValidatorCCC>(*this);
2311 }
2312
2313 private:
2314 RecordDecl *Record;
2315 };
2316
2317 } // end anonymous namespace
2318
2319 /// Check the well-formedness of a C99 designated initializer.
2320 ///
2321 /// Determines whether the designated initializer @p DIE, which
2322 /// resides at the given @p Index within the initializer list @p
2323 /// IList, is well-formed for a current object of type @p DeclType
2324 /// (C99 6.7.8). The actual subobject that this designator refers to
2325 /// within the current subobject is returned in either
2326 /// @p NextField or @p NextElementIndex (whichever is appropriate).
2327 ///
2328 /// @param IList The initializer list in which this designated
2329 /// initializer occurs.
2330 ///
2331 /// @param DIE The designated initializer expression.
2332 ///
2333 /// @param DesigIdx The index of the current designator.
2334 ///
2335 /// @param CurrentObjectType The type of the "current object" (C99 6.7.8p17),
2336 /// into which the designation in @p DIE should refer.
2337 ///
2338 /// @param NextField If non-NULL and the first designator in @p DIE is
2339 /// a field, this will be set to the field declaration corresponding
2340 /// to the field named by the designator. On input, this is expected to be
2341 /// the next field that would be initialized in the absence of designation,
2342 /// if the complete object being initialized is a struct.
2343 ///
2344 /// @param NextElementIndex If non-NULL and the first designator in @p
2345 /// DIE is an array designator or GNU array-range designator, this
2346 /// will be set to the last index initialized by this designator.
2347 ///
2348 /// @param Index Index into @p IList where the designated initializer
2349 /// @p DIE occurs.
2350 ///
2351 /// @param StructuredList The initializer list expression that
2352 /// describes all of the subobject initializers in the order they'll
2353 /// actually be initialized.
2354 ///
2355 /// @returns true if there was an error, false otherwise.
2356 bool
CheckDesignatedInitializer(const InitializedEntity & Entity,InitListExpr * IList,DesignatedInitExpr * DIE,unsigned DesigIdx,QualType & CurrentObjectType,RecordDecl::field_iterator * NextField,llvm::APSInt * NextElementIndex,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex,bool FinishSubobjectInit,bool TopLevelObject)2357 InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity,
2358 InitListExpr *IList,
2359 DesignatedInitExpr *DIE,
2360 unsigned DesigIdx,
2361 QualType &CurrentObjectType,
2362 RecordDecl::field_iterator *NextField,
2363 llvm::APSInt *NextElementIndex,
2364 unsigned &Index,
2365 InitListExpr *StructuredList,
2366 unsigned &StructuredIndex,
2367 bool FinishSubobjectInit,
2368 bool TopLevelObject) {
2369 if (DesigIdx == DIE->size()) {
2370 // C++20 designated initialization can result in direct-list-initialization
2371 // of the designated subobject. This is the only way that we can end up
2372 // performing direct initialization as part of aggregate initialization, so
2373 // it needs special handling.
2374 if (DIE->isDirectInit()) {
2375 Expr *Init = DIE->getInit();
2376 assert(isa<InitListExpr>(Init) &&
2377 "designator result in direct non-list initialization?");
2378 InitializationKind Kind = InitializationKind::CreateDirectList(
2379 DIE->getBeginLoc(), Init->getBeginLoc(), Init->getEndLoc());
2380 InitializationSequence Seq(SemaRef, Entity, Kind, Init,
2381 /*TopLevelOfInitList*/ true);
2382 if (StructuredList) {
2383 ExprResult Result = VerifyOnly
2384 ? getDummyInit()
2385 : Seq.Perform(SemaRef, Entity, Kind, Init);
2386 UpdateStructuredListElement(StructuredList, StructuredIndex,
2387 Result.get());
2388 }
2389 ++Index;
2390 return !Seq;
2391 }
2392
2393 // Check the actual initialization for the designated object type.
2394 bool prevHadError = hadError;
2395
2396 // Temporarily remove the designator expression from the
2397 // initializer list that the child calls see, so that we don't try
2398 // to re-process the designator.
2399 unsigned OldIndex = Index;
2400 IList->setInit(OldIndex, DIE->getInit());
2401
2402 CheckSubElementType(Entity, IList, CurrentObjectType, Index,
2403 StructuredList, StructuredIndex);
2404
2405 // Restore the designated initializer expression in the syntactic
2406 // form of the initializer list.
2407 if (IList->getInit(OldIndex) != DIE->getInit())
2408 DIE->setInit(IList->getInit(OldIndex));
2409 IList->setInit(OldIndex, DIE);
2410
2411 return hadError && !prevHadError;
2412 }
2413
2414 DesignatedInitExpr::Designator *D = DIE->getDesignator(DesigIdx);
2415 bool IsFirstDesignator = (DesigIdx == 0);
2416 if (IsFirstDesignator ? FullyStructuredList : StructuredList) {
2417 // Determine the structural initializer list that corresponds to the
2418 // current subobject.
2419 if (IsFirstDesignator)
2420 StructuredList = FullyStructuredList;
2421 else {
2422 Expr *ExistingInit = StructuredIndex < StructuredList->getNumInits() ?
2423 StructuredList->getInit(StructuredIndex) : nullptr;
2424 if (!ExistingInit && StructuredList->hasArrayFiller())
2425 ExistingInit = StructuredList->getArrayFiller();
2426
2427 if (!ExistingInit)
2428 StructuredList = getStructuredSubobjectInit(
2429 IList, Index, CurrentObjectType, StructuredList, StructuredIndex,
2430 SourceRange(D->getBeginLoc(), DIE->getEndLoc()));
2431 else if (InitListExpr *Result = dyn_cast<InitListExpr>(ExistingInit))
2432 StructuredList = Result;
2433 else {
2434 // We are creating an initializer list that initializes the
2435 // subobjects of the current object, but there was already an
2436 // initialization that completely initialized the current
2437 // subobject, e.g., by a compound literal:
2438 //
2439 // struct X { int a, b; };
2440 // struct X xs[] = { [0] = (struct X) { 1, 2 }, [0].b = 3 };
2441 //
2442 // Here, xs[0].a == 1 and xs[0].b == 3, since the second,
2443 // designated initializer re-initializes only its current object
2444 // subobject [0].b.
2445 diagnoseInitOverride(ExistingInit,
2446 SourceRange(D->getBeginLoc(), DIE->getEndLoc()),
2447 /*FullyOverwritten=*/false);
2448
2449 if (!VerifyOnly) {
2450 if (DesignatedInitUpdateExpr *E =
2451 dyn_cast<DesignatedInitUpdateExpr>(ExistingInit))
2452 StructuredList = E->getUpdater();
2453 else {
2454 DesignatedInitUpdateExpr *DIUE = new (SemaRef.Context)
2455 DesignatedInitUpdateExpr(SemaRef.Context, D->getBeginLoc(),
2456 ExistingInit, DIE->getEndLoc());
2457 StructuredList->updateInit(SemaRef.Context, StructuredIndex, DIUE);
2458 StructuredList = DIUE->getUpdater();
2459 }
2460 } else {
2461 // We don't need to track the structured representation of a
2462 // designated init update of an already-fully-initialized object in
2463 // verify-only mode. The only reason we would need the structure is
2464 // to determine where the uninitialized "holes" are, and in this
2465 // case, we know there aren't any and we can't introduce any.
2466 StructuredList = nullptr;
2467 }
2468 }
2469 }
2470 }
2471
2472 if (D->isFieldDesignator()) {
2473 // C99 6.7.8p7:
2474 //
2475 // If a designator has the form
2476 //
2477 // . identifier
2478 //
2479 // then the current object (defined below) shall have
2480 // structure or union type and the identifier shall be the
2481 // name of a member of that type.
2482 const RecordType *RT = CurrentObjectType->getAs<RecordType>();
2483 if (!RT) {
2484 SourceLocation Loc = D->getDotLoc();
2485 if (Loc.isInvalid())
2486 Loc = D->getFieldLoc();
2487 if (!VerifyOnly)
2488 SemaRef.Diag(Loc, diag::err_field_designator_non_aggr)
2489 << SemaRef.getLangOpts().CPlusPlus << CurrentObjectType;
2490 ++Index;
2491 return true;
2492 }
2493
2494 FieldDecl *KnownField = D->getField();
2495 if (!KnownField) {
2496 IdentifierInfo *FieldName = D->getFieldName();
2497 DeclContext::lookup_result Lookup = RT->getDecl()->lookup(FieldName);
2498 for (NamedDecl *ND : Lookup) {
2499 if (auto *FD = dyn_cast<FieldDecl>(ND)) {
2500 KnownField = FD;
2501 break;
2502 }
2503 if (auto *IFD = dyn_cast<IndirectFieldDecl>(ND)) {
2504 // In verify mode, don't modify the original.
2505 if (VerifyOnly)
2506 DIE = CloneDesignatedInitExpr(SemaRef, DIE);
2507 ExpandAnonymousFieldDesignator(SemaRef, DIE, DesigIdx, IFD);
2508 D = DIE->getDesignator(DesigIdx);
2509 KnownField = cast<FieldDecl>(*IFD->chain_begin());
2510 break;
2511 }
2512 }
2513 if (!KnownField) {
2514 if (VerifyOnly) {
2515 ++Index;
2516 return true; // No typo correction when just trying this out.
2517 }
2518
2519 // Name lookup found something, but it wasn't a field.
2520 if (!Lookup.empty()) {
2521 SemaRef.Diag(D->getFieldLoc(), diag::err_field_designator_nonfield)
2522 << FieldName;
2523 SemaRef.Diag(Lookup.front()->getLocation(),
2524 diag::note_field_designator_found);
2525 ++Index;
2526 return true;
2527 }
2528
2529 // Name lookup didn't find anything.
2530 // Determine whether this was a typo for another field name.
2531 FieldInitializerValidatorCCC CCC(RT->getDecl());
2532 if (TypoCorrection Corrected = SemaRef.CorrectTypo(
2533 DeclarationNameInfo(FieldName, D->getFieldLoc()),
2534 Sema::LookupMemberName, /*Scope=*/nullptr, /*SS=*/nullptr, CCC,
2535 Sema::CTK_ErrorRecovery, RT->getDecl())) {
2536 SemaRef.diagnoseTypo(
2537 Corrected,
2538 SemaRef.PDiag(diag::err_field_designator_unknown_suggest)
2539 << FieldName << CurrentObjectType);
2540 KnownField = Corrected.getCorrectionDeclAs<FieldDecl>();
2541 hadError = true;
2542 } else {
2543 // Typo correction didn't find anything.
2544 SemaRef.Diag(D->getFieldLoc(), diag::err_field_designator_unknown)
2545 << FieldName << CurrentObjectType;
2546 ++Index;
2547 return true;
2548 }
2549 }
2550 }
2551
2552 unsigned NumBases = 0;
2553 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RT->getDecl()))
2554 NumBases = CXXRD->getNumBases();
2555
2556 unsigned FieldIndex = NumBases;
2557
2558 for (auto *FI : RT->getDecl()->fields()) {
2559 if (FI->isUnnamedBitfield())
2560 continue;
2561 if (declaresSameEntity(KnownField, FI)) {
2562 KnownField = FI;
2563 break;
2564 }
2565 ++FieldIndex;
2566 }
2567
2568 RecordDecl::field_iterator Field =
2569 RecordDecl::field_iterator(DeclContext::decl_iterator(KnownField));
2570
2571 // All of the fields of a union are located at the same place in
2572 // the initializer list.
2573 if (RT->getDecl()->isUnion()) {
2574 FieldIndex = 0;
2575 if (StructuredList) {
2576 FieldDecl *CurrentField = StructuredList->getInitializedFieldInUnion();
2577 if (CurrentField && !declaresSameEntity(CurrentField, *Field)) {
2578 assert(StructuredList->getNumInits() == 1
2579 && "A union should never have more than one initializer!");
2580
2581 Expr *ExistingInit = StructuredList->getInit(0);
2582 if (ExistingInit) {
2583 // We're about to throw away an initializer, emit warning.
2584 diagnoseInitOverride(
2585 ExistingInit, SourceRange(D->getBeginLoc(), DIE->getEndLoc()));
2586 }
2587
2588 // remove existing initializer
2589 StructuredList->resizeInits(SemaRef.Context, 0);
2590 StructuredList->setInitializedFieldInUnion(nullptr);
2591 }
2592
2593 StructuredList->setInitializedFieldInUnion(*Field);
2594 }
2595 }
2596
2597 // Make sure we can use this declaration.
2598 bool InvalidUse;
2599 if (VerifyOnly)
2600 InvalidUse = !SemaRef.CanUseDecl(*Field, TreatUnavailableAsInvalid);
2601 else
2602 InvalidUse = SemaRef.DiagnoseUseOfDecl(*Field, D->getFieldLoc());
2603 if (InvalidUse) {
2604 ++Index;
2605 return true;
2606 }
2607
2608 // C++20 [dcl.init.list]p3:
2609 // The ordered identifiers in the designators of the designated-
2610 // initializer-list shall form a subsequence of the ordered identifiers
2611 // in the direct non-static data members of T.
2612 //
2613 // Note that this is not a condition on forming the aggregate
2614 // initialization, only on actually performing initialization,
2615 // so it is not checked in VerifyOnly mode.
2616 //
2617 // FIXME: This is the only reordering diagnostic we produce, and it only
2618 // catches cases where we have a top-level field designator that jumps
2619 // backwards. This is the only such case that is reachable in an
2620 // otherwise-valid C++20 program, so is the only case that's required for
2621 // conformance, but for consistency, we should diagnose all the other
2622 // cases where a designator takes us backwards too.
2623 if (IsFirstDesignator && !VerifyOnly && SemaRef.getLangOpts().CPlusPlus &&
2624 NextField &&
2625 (*NextField == RT->getDecl()->field_end() ||
2626 (*NextField)->getFieldIndex() > Field->getFieldIndex() + 1)) {
2627 // Find the field that we just initialized.
2628 FieldDecl *PrevField = nullptr;
2629 for (auto FI = RT->getDecl()->field_begin();
2630 FI != RT->getDecl()->field_end(); ++FI) {
2631 if (FI->isUnnamedBitfield())
2632 continue;
2633 if (*NextField != RT->getDecl()->field_end() &&
2634 declaresSameEntity(*FI, **NextField))
2635 break;
2636 PrevField = *FI;
2637 }
2638
2639 if (PrevField &&
2640 PrevField->getFieldIndex() > KnownField->getFieldIndex()) {
2641 SemaRef.Diag(DIE->getBeginLoc(), diag::ext_designated_init_reordered)
2642 << KnownField << PrevField << DIE->getSourceRange();
2643
2644 unsigned OldIndex = NumBases + PrevField->getFieldIndex();
2645 if (StructuredList && OldIndex <= StructuredList->getNumInits()) {
2646 if (Expr *PrevInit = StructuredList->getInit(OldIndex)) {
2647 SemaRef.Diag(PrevInit->getBeginLoc(),
2648 diag::note_previous_field_init)
2649 << PrevField << PrevInit->getSourceRange();
2650 }
2651 }
2652 }
2653 }
2654
2655
2656 // Update the designator with the field declaration.
2657 if (!VerifyOnly)
2658 D->setField(*Field);
2659
2660 // Make sure that our non-designated initializer list has space
2661 // for a subobject corresponding to this field.
2662 if (StructuredList && FieldIndex >= StructuredList->getNumInits())
2663 StructuredList->resizeInits(SemaRef.Context, FieldIndex + 1);
2664
2665 // This designator names a flexible array member.
2666 if (Field->getType()->isIncompleteArrayType()) {
2667 bool Invalid = false;
2668 if ((DesigIdx + 1) != DIE->size()) {
2669 // We can't designate an object within the flexible array
2670 // member (because GCC doesn't allow it).
2671 if (!VerifyOnly) {
2672 DesignatedInitExpr::Designator *NextD
2673 = DIE->getDesignator(DesigIdx + 1);
2674 SemaRef.Diag(NextD->getBeginLoc(),
2675 diag::err_designator_into_flexible_array_member)
2676 << SourceRange(NextD->getBeginLoc(), DIE->getEndLoc());
2677 SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
2678 << *Field;
2679 }
2680 Invalid = true;
2681 }
2682
2683 if (!hadError && !isa<InitListExpr>(DIE->getInit()) &&
2684 !isa<StringLiteral>(DIE->getInit())) {
2685 // The initializer is not an initializer list.
2686 if (!VerifyOnly) {
2687 SemaRef.Diag(DIE->getInit()->getBeginLoc(),
2688 diag::err_flexible_array_init_needs_braces)
2689 << DIE->getInit()->getSourceRange();
2690 SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
2691 << *Field;
2692 }
2693 Invalid = true;
2694 }
2695
2696 // Check GNU flexible array initializer.
2697 if (!Invalid && CheckFlexibleArrayInit(Entity, DIE->getInit(), *Field,
2698 TopLevelObject))
2699 Invalid = true;
2700
2701 if (Invalid) {
2702 ++Index;
2703 return true;
2704 }
2705
2706 // Initialize the array.
2707 bool prevHadError = hadError;
2708 unsigned newStructuredIndex = FieldIndex;
2709 unsigned OldIndex = Index;
2710 IList->setInit(Index, DIE->getInit());
2711
2712 InitializedEntity MemberEntity =
2713 InitializedEntity::InitializeMember(*Field, &Entity);
2714 CheckSubElementType(MemberEntity, IList, Field->getType(), Index,
2715 StructuredList, newStructuredIndex);
2716
2717 IList->setInit(OldIndex, DIE);
2718 if (hadError && !prevHadError) {
2719 ++Field;
2720 ++FieldIndex;
2721 if (NextField)
2722 *NextField = Field;
2723 StructuredIndex = FieldIndex;
2724 return true;
2725 }
2726 } else {
2727 // Recurse to check later designated subobjects.
2728 QualType FieldType = Field->getType();
2729 unsigned newStructuredIndex = FieldIndex;
2730
2731 InitializedEntity MemberEntity =
2732 InitializedEntity::InitializeMember(*Field, &Entity);
2733 if (CheckDesignatedInitializer(MemberEntity, IList, DIE, DesigIdx + 1,
2734 FieldType, nullptr, nullptr, Index,
2735 StructuredList, newStructuredIndex,
2736 FinishSubobjectInit, false))
2737 return true;
2738 }
2739
2740 // Find the position of the next field to be initialized in this
2741 // subobject.
2742 ++Field;
2743 ++FieldIndex;
2744
2745 // If this the first designator, our caller will continue checking
2746 // the rest of this struct/class/union subobject.
2747 if (IsFirstDesignator) {
2748 if (NextField)
2749 *NextField = Field;
2750 StructuredIndex = FieldIndex;
2751 return false;
2752 }
2753
2754 if (!FinishSubobjectInit)
2755 return false;
2756
2757 // We've already initialized something in the union; we're done.
2758 if (RT->getDecl()->isUnion())
2759 return hadError;
2760
2761 // Check the remaining fields within this class/struct/union subobject.
2762 bool prevHadError = hadError;
2763
2764 auto NoBases =
2765 CXXRecordDecl::base_class_range(CXXRecordDecl::base_class_iterator(),
2766 CXXRecordDecl::base_class_iterator());
2767 CheckStructUnionTypes(Entity, IList, CurrentObjectType, NoBases, Field,
2768 false, Index, StructuredList, FieldIndex);
2769 return hadError && !prevHadError;
2770 }
2771
2772 // C99 6.7.8p6:
2773 //
2774 // If a designator has the form
2775 //
2776 // [ constant-expression ]
2777 //
2778 // then the current object (defined below) shall have array
2779 // type and the expression shall be an integer constant
2780 // expression. If the array is of unknown size, any
2781 // nonnegative value is valid.
2782 //
2783 // Additionally, cope with the GNU extension that permits
2784 // designators of the form
2785 //
2786 // [ constant-expression ... constant-expression ]
2787 const ArrayType *AT = SemaRef.Context.getAsArrayType(CurrentObjectType);
2788 if (!AT) {
2789 if (!VerifyOnly)
2790 SemaRef.Diag(D->getLBracketLoc(), diag::err_array_designator_non_array)
2791 << CurrentObjectType;
2792 ++Index;
2793 return true;
2794 }
2795
2796 Expr *IndexExpr = nullptr;
2797 llvm::APSInt DesignatedStartIndex, DesignatedEndIndex;
2798 if (D->isArrayDesignator()) {
2799 IndexExpr = DIE->getArrayIndex(*D);
2800 DesignatedStartIndex = IndexExpr->EvaluateKnownConstInt(SemaRef.Context);
2801 DesignatedEndIndex = DesignatedStartIndex;
2802 } else {
2803 assert(D->isArrayRangeDesignator() && "Need array-range designator");
2804
2805 DesignatedStartIndex =
2806 DIE->getArrayRangeStart(*D)->EvaluateKnownConstInt(SemaRef.Context);
2807 DesignatedEndIndex =
2808 DIE->getArrayRangeEnd(*D)->EvaluateKnownConstInt(SemaRef.Context);
2809 IndexExpr = DIE->getArrayRangeEnd(*D);
2810
2811 // Codegen can't handle evaluating array range designators that have side
2812 // effects, because we replicate the AST value for each initialized element.
2813 // As such, set the sawArrayRangeDesignator() bit if we initialize multiple
2814 // elements with something that has a side effect, so codegen can emit an
2815 // "error unsupported" error instead of miscompiling the app.
2816 if (DesignatedStartIndex.getZExtValue()!=DesignatedEndIndex.getZExtValue()&&
2817 DIE->getInit()->HasSideEffects(SemaRef.Context) && !VerifyOnly)
2818 FullyStructuredList->sawArrayRangeDesignator();
2819 }
2820
2821 if (isa<ConstantArrayType>(AT)) {
2822 llvm::APSInt MaxElements(cast<ConstantArrayType>(AT)->getSize(), false);
2823 DesignatedStartIndex
2824 = DesignatedStartIndex.extOrTrunc(MaxElements.getBitWidth());
2825 DesignatedStartIndex.setIsUnsigned(MaxElements.isUnsigned());
2826 DesignatedEndIndex
2827 = DesignatedEndIndex.extOrTrunc(MaxElements.getBitWidth());
2828 DesignatedEndIndex.setIsUnsigned(MaxElements.isUnsigned());
2829 if (DesignatedEndIndex >= MaxElements) {
2830 if (!VerifyOnly)
2831 SemaRef.Diag(IndexExpr->getBeginLoc(),
2832 diag::err_array_designator_too_large)
2833 << DesignatedEndIndex.toString(10) << MaxElements.toString(10)
2834 << IndexExpr->getSourceRange();
2835 ++Index;
2836 return true;
2837 }
2838 } else {
2839 unsigned DesignatedIndexBitWidth =
2840 ConstantArrayType::getMaxSizeBits(SemaRef.Context);
2841 DesignatedStartIndex =
2842 DesignatedStartIndex.extOrTrunc(DesignatedIndexBitWidth);
2843 DesignatedEndIndex =
2844 DesignatedEndIndex.extOrTrunc(DesignatedIndexBitWidth);
2845 DesignatedStartIndex.setIsUnsigned(true);
2846 DesignatedEndIndex.setIsUnsigned(true);
2847 }
2848
2849 bool IsStringLiteralInitUpdate =
2850 StructuredList && StructuredList->isStringLiteralInit();
2851 if (IsStringLiteralInitUpdate && VerifyOnly) {
2852 // We're just verifying an update to a string literal init. We don't need
2853 // to split the string up into individual characters to do that.
2854 StructuredList = nullptr;
2855 } else if (IsStringLiteralInitUpdate) {
2856 // We're modifying a string literal init; we have to decompose the string
2857 // so we can modify the individual characters.
2858 ASTContext &Context = SemaRef.Context;
2859 Expr *SubExpr = StructuredList->getInit(0)->IgnoreParens();
2860
2861 // Compute the character type
2862 QualType CharTy = AT->getElementType();
2863
2864 // Compute the type of the integer literals.
2865 QualType PromotedCharTy = CharTy;
2866 if (CharTy->isPromotableIntegerType())
2867 PromotedCharTy = Context.getPromotedIntegerType(CharTy);
2868 unsigned PromotedCharTyWidth = Context.getTypeSize(PromotedCharTy);
2869
2870 if (StringLiteral *SL = dyn_cast<StringLiteral>(SubExpr)) {
2871 // Get the length of the string.
2872 uint64_t StrLen = SL->getLength();
2873 if (cast<ConstantArrayType>(AT)->getSize().ult(StrLen))
2874 StrLen = cast<ConstantArrayType>(AT)->getSize().getZExtValue();
2875 StructuredList->resizeInits(Context, StrLen);
2876
2877 // Build a literal for each character in the string, and put them into
2878 // the init list.
2879 for (unsigned i = 0, e = StrLen; i != e; ++i) {
2880 llvm::APInt CodeUnit(PromotedCharTyWidth, SL->getCodeUnit(i));
2881 Expr *Init = new (Context) IntegerLiteral(
2882 Context, CodeUnit, PromotedCharTy, SubExpr->getExprLoc());
2883 if (CharTy != PromotedCharTy)
2884 Init = ImplicitCastExpr::Create(Context, CharTy, CK_IntegralCast,
2885 Init, nullptr, VK_RValue);
2886 StructuredList->updateInit(Context, i, Init);
2887 }
2888 } else {
2889 ObjCEncodeExpr *E = cast<ObjCEncodeExpr>(SubExpr);
2890 std::string Str;
2891 Context.getObjCEncodingForType(E->getEncodedType(), Str);
2892
2893 // Get the length of the string.
2894 uint64_t StrLen = Str.size();
2895 if (cast<ConstantArrayType>(AT)->getSize().ult(StrLen))
2896 StrLen = cast<ConstantArrayType>(AT)->getSize().getZExtValue();
2897 StructuredList->resizeInits(Context, StrLen);
2898
2899 // Build a literal for each character in the string, and put them into
2900 // the init list.
2901 for (unsigned i = 0, e = StrLen; i != e; ++i) {
2902 llvm::APInt CodeUnit(PromotedCharTyWidth, Str[i]);
2903 Expr *Init = new (Context) IntegerLiteral(
2904 Context, CodeUnit, PromotedCharTy, SubExpr->getExprLoc());
2905 if (CharTy != PromotedCharTy)
2906 Init = ImplicitCastExpr::Create(Context, CharTy, CK_IntegralCast,
2907 Init, nullptr, VK_RValue);
2908 StructuredList->updateInit(Context, i, Init);
2909 }
2910 }
2911 }
2912
2913 // Make sure that our non-designated initializer list has space
2914 // for a subobject corresponding to this array element.
2915 if (StructuredList &&
2916 DesignatedEndIndex.getZExtValue() >= StructuredList->getNumInits())
2917 StructuredList->resizeInits(SemaRef.Context,
2918 DesignatedEndIndex.getZExtValue() + 1);
2919
2920 // Repeatedly perform subobject initializations in the range
2921 // [DesignatedStartIndex, DesignatedEndIndex].
2922
2923 // Move to the next designator
2924 unsigned ElementIndex = DesignatedStartIndex.getZExtValue();
2925 unsigned OldIndex = Index;
2926
2927 InitializedEntity ElementEntity =
2928 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
2929
2930 while (DesignatedStartIndex <= DesignatedEndIndex) {
2931 // Recurse to check later designated subobjects.
2932 QualType ElementType = AT->getElementType();
2933 Index = OldIndex;
2934
2935 ElementEntity.setElementIndex(ElementIndex);
2936 if (CheckDesignatedInitializer(
2937 ElementEntity, IList, DIE, DesigIdx + 1, ElementType, nullptr,
2938 nullptr, Index, StructuredList, ElementIndex,
2939 FinishSubobjectInit && (DesignatedStartIndex == DesignatedEndIndex),
2940 false))
2941 return true;
2942
2943 // Move to the next index in the array that we'll be initializing.
2944 ++DesignatedStartIndex;
2945 ElementIndex = DesignatedStartIndex.getZExtValue();
2946 }
2947
2948 // If this the first designator, our caller will continue checking
2949 // the rest of this array subobject.
2950 if (IsFirstDesignator) {
2951 if (NextElementIndex)
2952 *NextElementIndex = DesignatedStartIndex;
2953 StructuredIndex = ElementIndex;
2954 return false;
2955 }
2956
2957 if (!FinishSubobjectInit)
2958 return false;
2959
2960 // Check the remaining elements within this array subobject.
2961 bool prevHadError = hadError;
2962 CheckArrayType(Entity, IList, CurrentObjectType, DesignatedStartIndex,
2963 /*SubobjectIsDesignatorContext=*/false, Index,
2964 StructuredList, ElementIndex);
2965 return hadError && !prevHadError;
2966 }
2967
2968 // Get the structured initializer list for a subobject of type
2969 // @p CurrentObjectType.
2970 InitListExpr *
getStructuredSubobjectInit(InitListExpr * IList,unsigned Index,QualType CurrentObjectType,InitListExpr * StructuredList,unsigned StructuredIndex,SourceRange InitRange,bool IsFullyOverwritten)2971 InitListChecker::getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
2972 QualType CurrentObjectType,
2973 InitListExpr *StructuredList,
2974 unsigned StructuredIndex,
2975 SourceRange InitRange,
2976 bool IsFullyOverwritten) {
2977 if (!StructuredList)
2978 return nullptr;
2979
2980 Expr *ExistingInit = nullptr;
2981 if (StructuredIndex < StructuredList->getNumInits())
2982 ExistingInit = StructuredList->getInit(StructuredIndex);
2983
2984 if (InitListExpr *Result = dyn_cast_or_null<InitListExpr>(ExistingInit))
2985 // There might have already been initializers for subobjects of the current
2986 // object, but a subsequent initializer list will overwrite the entirety
2987 // of the current object. (See DR 253 and C99 6.7.8p21). e.g.,
2988 //
2989 // struct P { char x[6]; };
2990 // struct P l = { .x[2] = 'x', .x = { [0] = 'f' } };
2991 //
2992 // The first designated initializer is ignored, and l.x is just "f".
2993 if (!IsFullyOverwritten)
2994 return Result;
2995
2996 if (ExistingInit) {
2997 // We are creating an initializer list that initializes the
2998 // subobjects of the current object, but there was already an
2999 // initialization that completely initialized the current
3000 // subobject:
3001 //
3002 // struct X { int a, b; };
3003 // struct X xs[] = { [0] = { 1, 2 }, [0].b = 3 };
3004 //
3005 // Here, xs[0].a == 1 and xs[0].b == 3, since the second,
3006 // designated initializer overwrites the [0].b initializer
3007 // from the prior initialization.
3008 //
3009 // When the existing initializer is an expression rather than an
3010 // initializer list, we cannot decompose and update it in this way.
3011 // For example:
3012 //
3013 // struct X xs[] = { [0] = (struct X) { 1, 2 }, [0].b = 3 };
3014 //
3015 // This case is handled by CheckDesignatedInitializer.
3016 diagnoseInitOverride(ExistingInit, InitRange);
3017 }
3018
3019 unsigned ExpectedNumInits = 0;
3020 if (Index < IList->getNumInits()) {
3021 if (auto *Init = dyn_cast_or_null<InitListExpr>(IList->getInit(Index)))
3022 ExpectedNumInits = Init->getNumInits();
3023 else
3024 ExpectedNumInits = IList->getNumInits() - Index;
3025 }
3026
3027 InitListExpr *Result =
3028 createInitListExpr(CurrentObjectType, InitRange, ExpectedNumInits);
3029
3030 // Link this new initializer list into the structured initializer
3031 // lists.
3032 StructuredList->updateInit(SemaRef.Context, StructuredIndex, Result);
3033 return Result;
3034 }
3035
3036 InitListExpr *
createInitListExpr(QualType CurrentObjectType,SourceRange InitRange,unsigned ExpectedNumInits)3037 InitListChecker::createInitListExpr(QualType CurrentObjectType,
3038 SourceRange InitRange,
3039 unsigned ExpectedNumInits) {
3040 InitListExpr *Result
3041 = new (SemaRef.Context) InitListExpr(SemaRef.Context,
3042 InitRange.getBegin(), None,
3043 InitRange.getEnd());
3044
3045 QualType ResultType = CurrentObjectType;
3046 if (!ResultType->isArrayType())
3047 ResultType = ResultType.getNonLValueExprType(SemaRef.Context);
3048 Result->setType(ResultType);
3049
3050 // Pre-allocate storage for the structured initializer list.
3051 unsigned NumElements = 0;
3052
3053 if (const ArrayType *AType
3054 = SemaRef.Context.getAsArrayType(CurrentObjectType)) {
3055 if (const ConstantArrayType *CAType = dyn_cast<ConstantArrayType>(AType)) {
3056 NumElements = CAType->getSize().getZExtValue();
3057 // Simple heuristic so that we don't allocate a very large
3058 // initializer with many empty entries at the end.
3059 if (NumElements > ExpectedNumInits)
3060 NumElements = 0;
3061 }
3062 } else if (const VectorType *VType = CurrentObjectType->getAs<VectorType>()) {
3063 NumElements = VType->getNumElements();
3064 } else if (CurrentObjectType->isRecordType()) {
3065 NumElements = numStructUnionElements(CurrentObjectType);
3066 }
3067
3068 Result->reserveInits(SemaRef.Context, NumElements);
3069
3070 return Result;
3071 }
3072
3073 /// Update the initializer at index @p StructuredIndex within the
3074 /// structured initializer list to the value @p expr.
UpdateStructuredListElement(InitListExpr * StructuredList,unsigned & StructuredIndex,Expr * expr)3075 void InitListChecker::UpdateStructuredListElement(InitListExpr *StructuredList,
3076 unsigned &StructuredIndex,
3077 Expr *expr) {
3078 // No structured initializer list to update
3079 if (!StructuredList)
3080 return;
3081
3082 if (Expr *PrevInit = StructuredList->updateInit(SemaRef.Context,
3083 StructuredIndex, expr)) {
3084 // This initializer overwrites a previous initializer. Warn.
3085 diagnoseInitOverride(PrevInit, expr->getSourceRange());
3086 }
3087
3088 ++StructuredIndex;
3089 }
3090
3091 /// Determine whether we can perform aggregate initialization for the purposes
3092 /// of overload resolution.
CanPerformAggregateInitializationForOverloadResolution(const InitializedEntity & Entity,InitListExpr * From)3093 bool Sema::CanPerformAggregateInitializationForOverloadResolution(
3094 const InitializedEntity &Entity, InitListExpr *From) {
3095 QualType Type = Entity.getType();
3096 InitListChecker Check(*this, Entity, From, Type, /*VerifyOnly=*/true,
3097 /*TreatUnavailableAsInvalid=*/false,
3098 /*InOverloadResolution=*/true);
3099 return !Check.HadError();
3100 }
3101
3102 /// Check that the given Index expression is a valid array designator
3103 /// value. This is essentially just a wrapper around
3104 /// VerifyIntegerConstantExpression that also checks for negative values
3105 /// and produces a reasonable diagnostic if there is a
3106 /// failure. Returns the index expression, possibly with an implicit cast
3107 /// added, on success. If everything went okay, Value will receive the
3108 /// value of the constant expression.
3109 static ExprResult
CheckArrayDesignatorExpr(Sema & S,Expr * Index,llvm::APSInt & Value)3110 CheckArrayDesignatorExpr(Sema &S, Expr *Index, llvm::APSInt &Value) {
3111 SourceLocation Loc = Index->getBeginLoc();
3112
3113 // Make sure this is an integer constant expression.
3114 ExprResult Result = S.VerifyIntegerConstantExpression(Index, &Value);
3115 if (Result.isInvalid())
3116 return Result;
3117
3118 if (Value.isSigned() && Value.isNegative())
3119 return S.Diag(Loc, diag::err_array_designator_negative)
3120 << Value.toString(10) << Index->getSourceRange();
3121
3122 Value.setIsUnsigned(true);
3123 return Result;
3124 }
3125
ActOnDesignatedInitializer(Designation & Desig,SourceLocation EqualOrColonLoc,bool GNUSyntax,ExprResult Init)3126 ExprResult Sema::ActOnDesignatedInitializer(Designation &Desig,
3127 SourceLocation EqualOrColonLoc,
3128 bool GNUSyntax,
3129 ExprResult Init) {
3130 typedef DesignatedInitExpr::Designator ASTDesignator;
3131
3132 bool Invalid = false;
3133 SmallVector<ASTDesignator, 32> Designators;
3134 SmallVector<Expr *, 32> InitExpressions;
3135
3136 // Build designators and check array designator expressions.
3137 for (unsigned Idx = 0; Idx < Desig.getNumDesignators(); ++Idx) {
3138 const Designator &D = Desig.getDesignator(Idx);
3139 switch (D.getKind()) {
3140 case Designator::FieldDesignator:
3141 Designators.push_back(ASTDesignator(D.getField(), D.getDotLoc(),
3142 D.getFieldLoc()));
3143 break;
3144
3145 case Designator::ArrayDesignator: {
3146 Expr *Index = static_cast<Expr *>(D.getArrayIndex());
3147 llvm::APSInt IndexValue;
3148 if (!Index->isTypeDependent() && !Index->isValueDependent())
3149 Index = CheckArrayDesignatorExpr(*this, Index, IndexValue).get();
3150 if (!Index)
3151 Invalid = true;
3152 else {
3153 Designators.push_back(ASTDesignator(InitExpressions.size(),
3154 D.getLBracketLoc(),
3155 D.getRBracketLoc()));
3156 InitExpressions.push_back(Index);
3157 }
3158 break;
3159 }
3160
3161 case Designator::ArrayRangeDesignator: {
3162 Expr *StartIndex = static_cast<Expr *>(D.getArrayRangeStart());
3163 Expr *EndIndex = static_cast<Expr *>(D.getArrayRangeEnd());
3164 llvm::APSInt StartValue;
3165 llvm::APSInt EndValue;
3166 bool StartDependent = StartIndex->isTypeDependent() ||
3167 StartIndex->isValueDependent();
3168 bool EndDependent = EndIndex->isTypeDependent() ||
3169 EndIndex->isValueDependent();
3170 if (!StartDependent)
3171 StartIndex =
3172 CheckArrayDesignatorExpr(*this, StartIndex, StartValue).get();
3173 if (!EndDependent)
3174 EndIndex = CheckArrayDesignatorExpr(*this, EndIndex, EndValue).get();
3175
3176 if (!StartIndex || !EndIndex)
3177 Invalid = true;
3178 else {
3179 // Make sure we're comparing values with the same bit width.
3180 if (StartDependent || EndDependent) {
3181 // Nothing to compute.
3182 } else if (StartValue.getBitWidth() > EndValue.getBitWidth())
3183 EndValue = EndValue.extend(StartValue.getBitWidth());
3184 else if (StartValue.getBitWidth() < EndValue.getBitWidth())
3185 StartValue = StartValue.extend(EndValue.getBitWidth());
3186
3187 if (!StartDependent && !EndDependent && EndValue < StartValue) {
3188 Diag(D.getEllipsisLoc(), diag::err_array_designator_empty_range)
3189 << StartValue.toString(10) << EndValue.toString(10)
3190 << StartIndex->getSourceRange() << EndIndex->getSourceRange();
3191 Invalid = true;
3192 } else {
3193 Designators.push_back(ASTDesignator(InitExpressions.size(),
3194 D.getLBracketLoc(),
3195 D.getEllipsisLoc(),
3196 D.getRBracketLoc()));
3197 InitExpressions.push_back(StartIndex);
3198 InitExpressions.push_back(EndIndex);
3199 }
3200 }
3201 break;
3202 }
3203 }
3204 }
3205
3206 if (Invalid || Init.isInvalid())
3207 return ExprError();
3208
3209 // Clear out the expressions within the designation.
3210 Desig.ClearExprs(*this);
3211
3212 return DesignatedInitExpr::Create(Context, Designators, InitExpressions,
3213 EqualOrColonLoc, GNUSyntax,
3214 Init.getAs<Expr>());
3215 }
3216
3217 //===----------------------------------------------------------------------===//
3218 // Initialization entity
3219 //===----------------------------------------------------------------------===//
3220
InitializedEntity(ASTContext & Context,unsigned Index,const InitializedEntity & Parent)3221 InitializedEntity::InitializedEntity(ASTContext &Context, unsigned Index,
3222 const InitializedEntity &Parent)
3223 : Parent(&Parent), Index(Index)
3224 {
3225 if (const ArrayType *AT = Context.getAsArrayType(Parent.getType())) {
3226 Kind = EK_ArrayElement;
3227 Type = AT->getElementType();
3228 } else if (const VectorType *VT = Parent.getType()->getAs<VectorType>()) {
3229 Kind = EK_VectorElement;
3230 Type = VT->getElementType();
3231 } else {
3232 const ComplexType *CT = Parent.getType()->getAs<ComplexType>();
3233 assert(CT && "Unexpected type");
3234 Kind = EK_ComplexElement;
3235 Type = CT->getElementType();
3236 }
3237 }
3238
3239 InitializedEntity
InitializeBase(ASTContext & Context,const CXXBaseSpecifier * Base,bool IsInheritedVirtualBase,const InitializedEntity * Parent)3240 InitializedEntity::InitializeBase(ASTContext &Context,
3241 const CXXBaseSpecifier *Base,
3242 bool IsInheritedVirtualBase,
3243 const InitializedEntity *Parent) {
3244 InitializedEntity Result;
3245 Result.Kind = EK_Base;
3246 Result.Parent = Parent;
3247 Result.Base = reinterpret_cast<uintptr_t>(Base);
3248 if (IsInheritedVirtualBase)
3249 Result.Base |= 0x01;
3250
3251 Result.Type = Base->getType();
3252 return Result;
3253 }
3254
getName() const3255 DeclarationName InitializedEntity::getName() const {
3256 switch (getKind()) {
3257 case EK_Parameter:
3258 case EK_Parameter_CF_Audited: {
3259 ParmVarDecl *D = reinterpret_cast<ParmVarDecl*>(Parameter & ~0x1);
3260 return (D ? D->getDeclName() : DeclarationName());
3261 }
3262
3263 case EK_Variable:
3264 case EK_Member:
3265 case EK_Binding:
3266 return Variable.VariableOrMember->getDeclName();
3267
3268 case EK_LambdaCapture:
3269 return DeclarationName(Capture.VarID);
3270
3271 case EK_Result:
3272 case EK_StmtExprResult:
3273 case EK_Exception:
3274 case EK_New:
3275 case EK_Temporary:
3276 case EK_Base:
3277 case EK_Delegating:
3278 case EK_ArrayElement:
3279 case EK_VectorElement:
3280 case EK_ComplexElement:
3281 case EK_BlockElement:
3282 case EK_LambdaToBlockConversionBlockElement:
3283 case EK_CompoundLiteralInit:
3284 case EK_RelatedResult:
3285 return DeclarationName();
3286 }
3287
3288 llvm_unreachable("Invalid EntityKind!");
3289 }
3290
getDecl() const3291 ValueDecl *InitializedEntity::getDecl() const {
3292 switch (getKind()) {
3293 case EK_Variable:
3294 case EK_Member:
3295 case EK_Binding:
3296 return Variable.VariableOrMember;
3297
3298 case EK_Parameter:
3299 case EK_Parameter_CF_Audited:
3300 return reinterpret_cast<ParmVarDecl*>(Parameter & ~0x1);
3301
3302 case EK_Result:
3303 case EK_StmtExprResult:
3304 case EK_Exception:
3305 case EK_New:
3306 case EK_Temporary:
3307 case EK_Base:
3308 case EK_Delegating:
3309 case EK_ArrayElement:
3310 case EK_VectorElement:
3311 case EK_ComplexElement:
3312 case EK_BlockElement:
3313 case EK_LambdaToBlockConversionBlockElement:
3314 case EK_LambdaCapture:
3315 case EK_CompoundLiteralInit:
3316 case EK_RelatedResult:
3317 return nullptr;
3318 }
3319
3320 llvm_unreachable("Invalid EntityKind!");
3321 }
3322
allowsNRVO() const3323 bool InitializedEntity::allowsNRVO() const {
3324 switch (getKind()) {
3325 case EK_Result:
3326 case EK_Exception:
3327 return LocAndNRVO.NRVO;
3328
3329 case EK_StmtExprResult:
3330 case EK_Variable:
3331 case EK_Parameter:
3332 case EK_Parameter_CF_Audited:
3333 case EK_Member:
3334 case EK_Binding:
3335 case EK_New:
3336 case EK_Temporary:
3337 case EK_CompoundLiteralInit:
3338 case EK_Base:
3339 case EK_Delegating:
3340 case EK_ArrayElement:
3341 case EK_VectorElement:
3342 case EK_ComplexElement:
3343 case EK_BlockElement:
3344 case EK_LambdaToBlockConversionBlockElement:
3345 case EK_LambdaCapture:
3346 case EK_RelatedResult:
3347 break;
3348 }
3349
3350 return false;
3351 }
3352
dumpImpl(raw_ostream & OS) const3353 unsigned InitializedEntity::dumpImpl(raw_ostream &OS) const {
3354 assert(getParent() != this);
3355 unsigned Depth = getParent() ? getParent()->dumpImpl(OS) : 0;
3356 for (unsigned I = 0; I != Depth; ++I)
3357 OS << "`-";
3358
3359 switch (getKind()) {
3360 case EK_Variable: OS << "Variable"; break;
3361 case EK_Parameter: OS << "Parameter"; break;
3362 case EK_Parameter_CF_Audited: OS << "CF audited function Parameter";
3363 break;
3364 case EK_Result: OS << "Result"; break;
3365 case EK_StmtExprResult: OS << "StmtExprResult"; break;
3366 case EK_Exception: OS << "Exception"; break;
3367 case EK_Member: OS << "Member"; break;
3368 case EK_Binding: OS << "Binding"; break;
3369 case EK_New: OS << "New"; break;
3370 case EK_Temporary: OS << "Temporary"; break;
3371 case EK_CompoundLiteralInit: OS << "CompoundLiteral";break;
3372 case EK_RelatedResult: OS << "RelatedResult"; break;
3373 case EK_Base: OS << "Base"; break;
3374 case EK_Delegating: OS << "Delegating"; break;
3375 case EK_ArrayElement: OS << "ArrayElement " << Index; break;
3376 case EK_VectorElement: OS << "VectorElement " << Index; break;
3377 case EK_ComplexElement: OS << "ComplexElement " << Index; break;
3378 case EK_BlockElement: OS << "Block"; break;
3379 case EK_LambdaToBlockConversionBlockElement:
3380 OS << "Block (lambda)";
3381 break;
3382 case EK_LambdaCapture:
3383 OS << "LambdaCapture ";
3384 OS << DeclarationName(Capture.VarID);
3385 break;
3386 }
3387
3388 if (auto *D = getDecl()) {
3389 OS << " ";
3390 D->printQualifiedName(OS);
3391 }
3392
3393 OS << " '" << getType().getAsString() << "'\n";
3394
3395 return Depth + 1;
3396 }
3397
dump() const3398 LLVM_DUMP_METHOD void InitializedEntity::dump() const {
3399 dumpImpl(llvm::errs());
3400 }
3401
3402 //===----------------------------------------------------------------------===//
3403 // Initialization sequence
3404 //===----------------------------------------------------------------------===//
3405
Destroy()3406 void InitializationSequence::Step::Destroy() {
3407 switch (Kind) {
3408 case SK_ResolveAddressOfOverloadedFunction:
3409 case SK_CastDerivedToBaseRValue:
3410 case SK_CastDerivedToBaseXValue:
3411 case SK_CastDerivedToBaseLValue:
3412 case SK_BindReference:
3413 case SK_BindReferenceToTemporary:
3414 case SK_FinalCopy:
3415 case SK_ExtraneousCopyToTemporary:
3416 case SK_UserConversion:
3417 case SK_QualificationConversionRValue:
3418 case SK_QualificationConversionXValue:
3419 case SK_QualificationConversionLValue:
3420 case SK_AtomicConversion:
3421 case SK_ListInitialization:
3422 case SK_UnwrapInitList:
3423 case SK_RewrapInitList:
3424 case SK_ConstructorInitialization:
3425 case SK_ConstructorInitializationFromList:
3426 case SK_ZeroInitialization:
3427 case SK_CAssignment:
3428 case SK_StringInit:
3429 case SK_ObjCObjectConversion:
3430 case SK_ArrayLoopIndex:
3431 case SK_ArrayLoopInit:
3432 case SK_ArrayInit:
3433 case SK_GNUArrayInit:
3434 case SK_ParenthesizedArrayInit:
3435 case SK_PassByIndirectCopyRestore:
3436 case SK_PassByIndirectRestore:
3437 case SK_ProduceObjCObject:
3438 case SK_StdInitializerList:
3439 case SK_StdInitializerListConstructorCall:
3440 case SK_OCLSamplerInit:
3441 case SK_OCLZeroOpaqueType:
3442 break;
3443
3444 case SK_ConversionSequence:
3445 case SK_ConversionSequenceNoNarrowing:
3446 delete ICS;
3447 }
3448 }
3449
isDirectReferenceBinding() const3450 bool InitializationSequence::isDirectReferenceBinding() const {
3451 // There can be some lvalue adjustments after the SK_BindReference step.
3452 for (auto I = Steps.rbegin(); I != Steps.rend(); ++I) {
3453 if (I->Kind == SK_BindReference)
3454 return true;
3455 if (I->Kind == SK_BindReferenceToTemporary)
3456 return false;
3457 }
3458 return false;
3459 }
3460
isAmbiguous() const3461 bool InitializationSequence::isAmbiguous() const {
3462 if (!Failed())
3463 return false;
3464
3465 switch (getFailureKind()) {
3466 case FK_TooManyInitsForReference:
3467 case FK_ParenthesizedListInitForReference:
3468 case FK_ArrayNeedsInitList:
3469 case FK_ArrayNeedsInitListOrStringLiteral:
3470 case FK_ArrayNeedsInitListOrWideStringLiteral:
3471 case FK_NarrowStringIntoWideCharArray:
3472 case FK_WideStringIntoCharArray:
3473 case FK_IncompatWideStringIntoWideChar:
3474 case FK_PlainStringIntoUTF8Char:
3475 case FK_UTF8StringIntoPlainChar:
3476 case FK_AddressOfOverloadFailed: // FIXME: Could do better
3477 case FK_NonConstLValueReferenceBindingToTemporary:
3478 case FK_NonConstLValueReferenceBindingToBitfield:
3479 case FK_NonConstLValueReferenceBindingToVectorElement:
3480 case FK_NonConstLValueReferenceBindingToUnrelated:
3481 case FK_RValueReferenceBindingToLValue:
3482 case FK_ReferenceAddrspaceMismatchTemporary:
3483 case FK_ReferenceInitDropsQualifiers:
3484 case FK_ReferenceInitFailed:
3485 case FK_ConversionFailed:
3486 case FK_ConversionFromPropertyFailed:
3487 case FK_TooManyInitsForScalar:
3488 case FK_ParenthesizedListInitForScalar:
3489 case FK_ReferenceBindingToInitList:
3490 case FK_InitListBadDestinationType:
3491 case FK_DefaultInitOfConst:
3492 case FK_Incomplete:
3493 case FK_ArrayTypeMismatch:
3494 case FK_NonConstantArrayInit:
3495 case FK_ListInitializationFailed:
3496 case FK_VariableLengthArrayHasInitializer:
3497 case FK_PlaceholderType:
3498 case FK_ExplicitConstructor:
3499 case FK_AddressOfUnaddressableFunction:
3500 return false;
3501
3502 case FK_ReferenceInitOverloadFailed:
3503 case FK_UserConversionOverloadFailed:
3504 case FK_ConstructorOverloadFailed:
3505 case FK_ListConstructorOverloadFailed:
3506 return FailedOverloadResult == OR_Ambiguous;
3507 }
3508
3509 llvm_unreachable("Invalid EntityKind!");
3510 }
3511
isConstructorInitialization() const3512 bool InitializationSequence::isConstructorInitialization() const {
3513 return !Steps.empty() && Steps.back().Kind == SK_ConstructorInitialization;
3514 }
3515
3516 void
3517 InitializationSequence
AddAddressOverloadResolutionStep(FunctionDecl * Function,DeclAccessPair Found,bool HadMultipleCandidates)3518 ::AddAddressOverloadResolutionStep(FunctionDecl *Function,
3519 DeclAccessPair Found,
3520 bool HadMultipleCandidates) {
3521 Step S;
3522 S.Kind = SK_ResolveAddressOfOverloadedFunction;
3523 S.Type = Function->getType();
3524 S.Function.HadMultipleCandidates = HadMultipleCandidates;
3525 S.Function.Function = Function;
3526 S.Function.FoundDecl = Found;
3527 Steps.push_back(S);
3528 }
3529
AddDerivedToBaseCastStep(QualType BaseType,ExprValueKind VK)3530 void InitializationSequence::AddDerivedToBaseCastStep(QualType BaseType,
3531 ExprValueKind VK) {
3532 Step S;
3533 switch (VK) {
3534 case VK_RValue: S.Kind = SK_CastDerivedToBaseRValue; break;
3535 case VK_XValue: S.Kind = SK_CastDerivedToBaseXValue; break;
3536 case VK_LValue: S.Kind = SK_CastDerivedToBaseLValue; break;
3537 }
3538 S.Type = BaseType;
3539 Steps.push_back(S);
3540 }
3541
AddReferenceBindingStep(QualType T,bool BindingTemporary)3542 void InitializationSequence::AddReferenceBindingStep(QualType T,
3543 bool BindingTemporary) {
3544 Step S;
3545 S.Kind = BindingTemporary? SK_BindReferenceToTemporary : SK_BindReference;
3546 S.Type = T;
3547 Steps.push_back(S);
3548 }
3549
AddFinalCopy(QualType T)3550 void InitializationSequence::AddFinalCopy(QualType T) {
3551 Step S;
3552 S.Kind = SK_FinalCopy;
3553 S.Type = T;
3554 Steps.push_back(S);
3555 }
3556
AddExtraneousCopyToTemporary(QualType T)3557 void InitializationSequence::AddExtraneousCopyToTemporary(QualType T) {
3558 Step S;
3559 S.Kind = SK_ExtraneousCopyToTemporary;
3560 S.Type = T;
3561 Steps.push_back(S);
3562 }
3563
3564 void
AddUserConversionStep(FunctionDecl * Function,DeclAccessPair FoundDecl,QualType T,bool HadMultipleCandidates)3565 InitializationSequence::AddUserConversionStep(FunctionDecl *Function,
3566 DeclAccessPair FoundDecl,
3567 QualType T,
3568 bool HadMultipleCandidates) {
3569 Step S;
3570 S.Kind = SK_UserConversion;
3571 S.Type = T;
3572 S.Function.HadMultipleCandidates = HadMultipleCandidates;
3573 S.Function.Function = Function;
3574 S.Function.FoundDecl = FoundDecl;
3575 Steps.push_back(S);
3576 }
3577
AddQualificationConversionStep(QualType Ty,ExprValueKind VK)3578 void InitializationSequence::AddQualificationConversionStep(QualType Ty,
3579 ExprValueKind VK) {
3580 Step S;
3581 S.Kind = SK_QualificationConversionRValue; // work around a gcc warning
3582 switch (VK) {
3583 case VK_RValue:
3584 S.Kind = SK_QualificationConversionRValue;
3585 break;
3586 case VK_XValue:
3587 S.Kind = SK_QualificationConversionXValue;
3588 break;
3589 case VK_LValue:
3590 S.Kind = SK_QualificationConversionLValue;
3591 break;
3592 }
3593 S.Type = Ty;
3594 Steps.push_back(S);
3595 }
3596
AddAtomicConversionStep(QualType Ty)3597 void InitializationSequence::AddAtomicConversionStep(QualType Ty) {
3598 Step S;
3599 S.Kind = SK_AtomicConversion;
3600 S.Type = Ty;
3601 Steps.push_back(S);
3602 }
3603
AddConversionSequenceStep(const ImplicitConversionSequence & ICS,QualType T,bool TopLevelOfInitList)3604 void InitializationSequence::AddConversionSequenceStep(
3605 const ImplicitConversionSequence &ICS, QualType T,
3606 bool TopLevelOfInitList) {
3607 Step S;
3608 S.Kind = TopLevelOfInitList ? SK_ConversionSequenceNoNarrowing
3609 : SK_ConversionSequence;
3610 S.Type = T;
3611 S.ICS = new ImplicitConversionSequence(ICS);
3612 Steps.push_back(S);
3613 }
3614
AddListInitializationStep(QualType T)3615 void InitializationSequence::AddListInitializationStep(QualType T) {
3616 Step S;
3617 S.Kind = SK_ListInitialization;
3618 S.Type = T;
3619 Steps.push_back(S);
3620 }
3621
AddConstructorInitializationStep(DeclAccessPair FoundDecl,CXXConstructorDecl * Constructor,QualType T,bool HadMultipleCandidates,bool FromInitList,bool AsInitList)3622 void InitializationSequence::AddConstructorInitializationStep(
3623 DeclAccessPair FoundDecl, CXXConstructorDecl *Constructor, QualType T,
3624 bool HadMultipleCandidates, bool FromInitList, bool AsInitList) {
3625 Step S;
3626 S.Kind = FromInitList ? AsInitList ? SK_StdInitializerListConstructorCall
3627 : SK_ConstructorInitializationFromList
3628 : SK_ConstructorInitialization;
3629 S.Type = T;
3630 S.Function.HadMultipleCandidates = HadMultipleCandidates;
3631 S.Function.Function = Constructor;
3632 S.Function.FoundDecl = FoundDecl;
3633 Steps.push_back(S);
3634 }
3635
AddZeroInitializationStep(QualType T)3636 void InitializationSequence::AddZeroInitializationStep(QualType T) {
3637 Step S;
3638 S.Kind = SK_ZeroInitialization;
3639 S.Type = T;
3640 Steps.push_back(S);
3641 }
3642
AddCAssignmentStep(QualType T)3643 void InitializationSequence::AddCAssignmentStep(QualType T) {
3644 Step S;
3645 S.Kind = SK_CAssignment;
3646 S.Type = T;
3647 Steps.push_back(S);
3648 }
3649
AddStringInitStep(QualType T)3650 void InitializationSequence::AddStringInitStep(QualType T) {
3651 Step S;
3652 S.Kind = SK_StringInit;
3653 S.Type = T;
3654 Steps.push_back(S);
3655 }
3656
AddObjCObjectConversionStep(QualType T)3657 void InitializationSequence::AddObjCObjectConversionStep(QualType T) {
3658 Step S;
3659 S.Kind = SK_ObjCObjectConversion;
3660 S.Type = T;
3661 Steps.push_back(S);
3662 }
3663
AddArrayInitStep(QualType T,bool IsGNUExtension)3664 void InitializationSequence::AddArrayInitStep(QualType T, bool IsGNUExtension) {
3665 Step S;
3666 S.Kind = IsGNUExtension ? SK_GNUArrayInit : SK_ArrayInit;
3667 S.Type = T;
3668 Steps.push_back(S);
3669 }
3670
AddArrayInitLoopStep(QualType T,QualType EltT)3671 void InitializationSequence::AddArrayInitLoopStep(QualType T, QualType EltT) {
3672 Step S;
3673 S.Kind = SK_ArrayLoopIndex;
3674 S.Type = EltT;
3675 Steps.insert(Steps.begin(), S);
3676
3677 S.Kind = SK_ArrayLoopInit;
3678 S.Type = T;
3679 Steps.push_back(S);
3680 }
3681
AddParenthesizedArrayInitStep(QualType T)3682 void InitializationSequence::AddParenthesizedArrayInitStep(QualType T) {
3683 Step S;
3684 S.Kind = SK_ParenthesizedArrayInit;
3685 S.Type = T;
3686 Steps.push_back(S);
3687 }
3688
AddPassByIndirectCopyRestoreStep(QualType type,bool shouldCopy)3689 void InitializationSequence::AddPassByIndirectCopyRestoreStep(QualType type,
3690 bool shouldCopy) {
3691 Step s;
3692 s.Kind = (shouldCopy ? SK_PassByIndirectCopyRestore
3693 : SK_PassByIndirectRestore);
3694 s.Type = type;
3695 Steps.push_back(s);
3696 }
3697
AddProduceObjCObjectStep(QualType T)3698 void InitializationSequence::AddProduceObjCObjectStep(QualType T) {
3699 Step S;
3700 S.Kind = SK_ProduceObjCObject;
3701 S.Type = T;
3702 Steps.push_back(S);
3703 }
3704
AddStdInitializerListConstructionStep(QualType T)3705 void InitializationSequence::AddStdInitializerListConstructionStep(QualType T) {
3706 Step S;
3707 S.Kind = SK_StdInitializerList;
3708 S.Type = T;
3709 Steps.push_back(S);
3710 }
3711
AddOCLSamplerInitStep(QualType T)3712 void InitializationSequence::AddOCLSamplerInitStep(QualType T) {
3713 Step S;
3714 S.Kind = SK_OCLSamplerInit;
3715 S.Type = T;
3716 Steps.push_back(S);
3717 }
3718
AddOCLZeroOpaqueTypeStep(QualType T)3719 void InitializationSequence::AddOCLZeroOpaqueTypeStep(QualType T) {
3720 Step S;
3721 S.Kind = SK_OCLZeroOpaqueType;
3722 S.Type = T;
3723 Steps.push_back(S);
3724 }
3725
RewrapReferenceInitList(QualType T,InitListExpr * Syntactic)3726 void InitializationSequence::RewrapReferenceInitList(QualType T,
3727 InitListExpr *Syntactic) {
3728 assert(Syntactic->getNumInits() == 1 &&
3729 "Can only rewrap trivial init lists.");
3730 Step S;
3731 S.Kind = SK_UnwrapInitList;
3732 S.Type = Syntactic->getInit(0)->getType();
3733 Steps.insert(Steps.begin(), S);
3734
3735 S.Kind = SK_RewrapInitList;
3736 S.Type = T;
3737 S.WrappingSyntacticList = Syntactic;
3738 Steps.push_back(S);
3739 }
3740
SetOverloadFailure(FailureKind Failure,OverloadingResult Result)3741 void InitializationSequence::SetOverloadFailure(FailureKind Failure,
3742 OverloadingResult Result) {
3743 setSequenceKind(FailedSequence);
3744 this->Failure = Failure;
3745 this->FailedOverloadResult = Result;
3746 }
3747
3748 //===----------------------------------------------------------------------===//
3749 // Attempt initialization
3750 //===----------------------------------------------------------------------===//
3751
3752 /// Tries to add a zero initializer. Returns true if that worked.
3753 static bool
maybeRecoverWithZeroInitialization(Sema & S,InitializationSequence & Sequence,const InitializedEntity & Entity)3754 maybeRecoverWithZeroInitialization(Sema &S, InitializationSequence &Sequence,
3755 const InitializedEntity &Entity) {
3756 if (Entity.getKind() != InitializedEntity::EK_Variable)
3757 return false;
3758
3759 VarDecl *VD = cast<VarDecl>(Entity.getDecl());
3760 if (VD->getInit() || VD->getEndLoc().isMacroID())
3761 return false;
3762
3763 QualType VariableTy = VD->getType().getCanonicalType();
3764 SourceLocation Loc = S.getLocForEndOfToken(VD->getEndLoc());
3765 std::string Init = S.getFixItZeroInitializerForType(VariableTy, Loc);
3766 if (!Init.empty()) {
3767 Sequence.AddZeroInitializationStep(Entity.getType());
3768 Sequence.SetZeroInitializationFixit(Init, Loc);
3769 return true;
3770 }
3771 return false;
3772 }
3773
MaybeProduceObjCObject(Sema & S,InitializationSequence & Sequence,const InitializedEntity & Entity)3774 static void MaybeProduceObjCObject(Sema &S,
3775 InitializationSequence &Sequence,
3776 const InitializedEntity &Entity) {
3777 if (!S.getLangOpts().ObjCAutoRefCount) return;
3778
3779 /// When initializing a parameter, produce the value if it's marked
3780 /// __attribute__((ns_consumed)).
3781 if (Entity.isParameterKind()) {
3782 if (!Entity.isParameterConsumed())
3783 return;
3784
3785 assert(Entity.getType()->isObjCRetainableType() &&
3786 "consuming an object of unretainable type?");
3787 Sequence.AddProduceObjCObjectStep(Entity.getType());
3788
3789 /// When initializing a return value, if the return type is a
3790 /// retainable type, then returns need to immediately retain the
3791 /// object. If an autorelease is required, it will be done at the
3792 /// last instant.
3793 } else if (Entity.getKind() == InitializedEntity::EK_Result ||
3794 Entity.getKind() == InitializedEntity::EK_StmtExprResult) {
3795 if (!Entity.getType()->isObjCRetainableType())
3796 return;
3797
3798 Sequence.AddProduceObjCObjectStep(Entity.getType());
3799 }
3800 }
3801
3802 static void TryListInitialization(Sema &S,
3803 const InitializedEntity &Entity,
3804 const InitializationKind &Kind,
3805 InitListExpr *InitList,
3806 InitializationSequence &Sequence,
3807 bool TreatUnavailableAsInvalid);
3808
3809 /// When initializing from init list via constructor, handle
3810 /// initialization of an object of type std::initializer_list<T>.
3811 ///
3812 /// \return true if we have handled initialization of an object of type
3813 /// std::initializer_list<T>, false otherwise.
TryInitializerListConstruction(Sema & S,InitListExpr * List,QualType DestType,InitializationSequence & Sequence,bool TreatUnavailableAsInvalid)3814 static bool TryInitializerListConstruction(Sema &S,
3815 InitListExpr *List,
3816 QualType DestType,
3817 InitializationSequence &Sequence,
3818 bool TreatUnavailableAsInvalid) {
3819 QualType E;
3820 if (!S.isStdInitializerList(DestType, &E))
3821 return false;
3822
3823 if (!S.isCompleteType(List->getExprLoc(), E)) {
3824 Sequence.setIncompleteTypeFailure(E);
3825 return true;
3826 }
3827
3828 // Try initializing a temporary array from the init list.
3829 QualType ArrayType = S.Context.getConstantArrayType(
3830 E.withConst(),
3831 llvm::APInt(S.Context.getTypeSize(S.Context.getSizeType()),
3832 List->getNumInits()),
3833 nullptr, clang::ArrayType::Normal, 0);
3834 InitializedEntity HiddenArray =
3835 InitializedEntity::InitializeTemporary(ArrayType);
3836 InitializationKind Kind = InitializationKind::CreateDirectList(
3837 List->getExprLoc(), List->getBeginLoc(), List->getEndLoc());
3838 TryListInitialization(S, HiddenArray, Kind, List, Sequence,
3839 TreatUnavailableAsInvalid);
3840 if (Sequence)
3841 Sequence.AddStdInitializerListConstructionStep(DestType);
3842 return true;
3843 }
3844
3845 /// Determine if the constructor has the signature of a copy or move
3846 /// constructor for the type T of the class in which it was found. That is,
3847 /// determine if its first parameter is of type T or reference to (possibly
3848 /// cv-qualified) T.
hasCopyOrMoveCtorParam(ASTContext & Ctx,const ConstructorInfo & Info)3849 static bool hasCopyOrMoveCtorParam(ASTContext &Ctx,
3850 const ConstructorInfo &Info) {
3851 if (Info.Constructor->getNumParams() == 0)
3852 return false;
3853
3854 QualType ParmT =
3855 Info.Constructor->getParamDecl(0)->getType().getNonReferenceType();
3856 QualType ClassT =
3857 Ctx.getRecordType(cast<CXXRecordDecl>(Info.FoundDecl->getDeclContext()));
3858
3859 return Ctx.hasSameUnqualifiedType(ParmT, ClassT);
3860 }
3861
3862 static OverloadingResult
ResolveConstructorOverload(Sema & S,SourceLocation DeclLoc,MultiExprArg Args,OverloadCandidateSet & CandidateSet,QualType DestType,DeclContext::lookup_result Ctors,OverloadCandidateSet::iterator & Best,bool CopyInitializing,bool AllowExplicit,bool OnlyListConstructors,bool IsListInit,bool SecondStepOfCopyInit=false)3863 ResolveConstructorOverload(Sema &S, SourceLocation DeclLoc,
3864 MultiExprArg Args,
3865 OverloadCandidateSet &CandidateSet,
3866 QualType DestType,
3867 DeclContext::lookup_result Ctors,
3868 OverloadCandidateSet::iterator &Best,
3869 bool CopyInitializing, bool AllowExplicit,
3870 bool OnlyListConstructors, bool IsListInit,
3871 bool SecondStepOfCopyInit = false) {
3872 CandidateSet.clear(OverloadCandidateSet::CSK_InitByConstructor);
3873 CandidateSet.setDestAS(DestType.getQualifiers().getAddressSpace());
3874
3875 for (NamedDecl *D : Ctors) {
3876 auto Info = getConstructorInfo(D);
3877 if (!Info.Constructor || Info.Constructor->isInvalidDecl())
3878 continue;
3879
3880 if (OnlyListConstructors && !S.isInitListConstructor(Info.Constructor))
3881 continue;
3882
3883 // C++11 [over.best.ics]p4:
3884 // ... and the constructor or user-defined conversion function is a
3885 // candidate by
3886 // - 13.3.1.3, when the argument is the temporary in the second step
3887 // of a class copy-initialization, or
3888 // - 13.3.1.4, 13.3.1.5, or 13.3.1.6 (in all cases), [not handled here]
3889 // - the second phase of 13.3.1.7 when the initializer list has exactly
3890 // one element that is itself an initializer list, and the target is
3891 // the first parameter of a constructor of class X, and the conversion
3892 // is to X or reference to (possibly cv-qualified X),
3893 // user-defined conversion sequences are not considered.
3894 bool SuppressUserConversions =
3895 SecondStepOfCopyInit ||
3896 (IsListInit && Args.size() == 1 && isa<InitListExpr>(Args[0]) &&
3897 hasCopyOrMoveCtorParam(S.Context, Info));
3898
3899 if (Info.ConstructorTmpl)
3900 S.AddTemplateOverloadCandidate(
3901 Info.ConstructorTmpl, Info.FoundDecl,
3902 /*ExplicitArgs*/ nullptr, Args, CandidateSet, SuppressUserConversions,
3903 /*PartialOverloading=*/false, AllowExplicit);
3904 else {
3905 // C++ [over.match.copy]p1:
3906 // - When initializing a temporary to be bound to the first parameter
3907 // of a constructor [for type T] that takes a reference to possibly
3908 // cv-qualified T as its first argument, called with a single
3909 // argument in the context of direct-initialization, explicit
3910 // conversion functions are also considered.
3911 // FIXME: What if a constructor template instantiates to such a signature?
3912 bool AllowExplicitConv = AllowExplicit && !CopyInitializing &&
3913 Args.size() == 1 &&
3914 hasCopyOrMoveCtorParam(S.Context, Info);
3915 S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, Args,
3916 CandidateSet, SuppressUserConversions,
3917 /*PartialOverloading=*/false, AllowExplicit,
3918 AllowExplicitConv);
3919 }
3920 }
3921
3922 // FIXME: Work around a bug in C++17 guaranteed copy elision.
3923 //
3924 // When initializing an object of class type T by constructor
3925 // ([over.match.ctor]) or by list-initialization ([over.match.list])
3926 // from a single expression of class type U, conversion functions of
3927 // U that convert to the non-reference type cv T are candidates.
3928 // Explicit conversion functions are only candidates during
3929 // direct-initialization.
3930 //
3931 // Note: SecondStepOfCopyInit is only ever true in this case when
3932 // evaluating whether to produce a C++98 compatibility warning.
3933 if (S.getLangOpts().CPlusPlus17 && Args.size() == 1 &&
3934 !SecondStepOfCopyInit) {
3935 Expr *Initializer = Args[0];
3936 auto *SourceRD = Initializer->getType()->getAsCXXRecordDecl();
3937 if (SourceRD && S.isCompleteType(DeclLoc, Initializer->getType())) {
3938 const auto &Conversions = SourceRD->getVisibleConversionFunctions();
3939 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
3940 NamedDecl *D = *I;
3941 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
3942 D = D->getUnderlyingDecl();
3943
3944 FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
3945 CXXConversionDecl *Conv;
3946 if (ConvTemplate)
3947 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
3948 else
3949 Conv = cast<CXXConversionDecl>(D);
3950
3951 if (ConvTemplate)
3952 S.AddTemplateConversionCandidate(
3953 ConvTemplate, I.getPair(), ActingDC, Initializer, DestType,
3954 CandidateSet, AllowExplicit, AllowExplicit,
3955 /*AllowResultConversion*/ false);
3956 else
3957 S.AddConversionCandidate(Conv, I.getPair(), ActingDC, Initializer,
3958 DestType, CandidateSet, AllowExplicit,
3959 AllowExplicit,
3960 /*AllowResultConversion*/ false);
3961 }
3962 }
3963 }
3964
3965 // Perform overload resolution and return the result.
3966 return CandidateSet.BestViableFunction(S, DeclLoc, Best);
3967 }
3968
3969 /// Attempt initialization by constructor (C++ [dcl.init]), which
3970 /// enumerates the constructors of the initialized entity and performs overload
3971 /// resolution to select the best.
3972 /// \param DestType The destination class type.
3973 /// \param DestArrayType The destination type, which is either DestType or
3974 /// a (possibly multidimensional) array of DestType.
3975 /// \param IsListInit Is this list-initialization?
3976 /// \param IsInitListCopy Is this non-list-initialization resulting from a
3977 /// list-initialization from {x} where x is the same
3978 /// type as the entity?
TryConstructorInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Args,QualType DestType,QualType DestArrayType,InitializationSequence & Sequence,bool IsListInit=false,bool IsInitListCopy=false)3979 static void TryConstructorInitialization(Sema &S,
3980 const InitializedEntity &Entity,
3981 const InitializationKind &Kind,
3982 MultiExprArg Args, QualType DestType,
3983 QualType DestArrayType,
3984 InitializationSequence &Sequence,
3985 bool IsListInit = false,
3986 bool IsInitListCopy = false) {
3987 assert(((!IsListInit && !IsInitListCopy) ||
3988 (Args.size() == 1 && isa<InitListExpr>(Args[0]))) &&
3989 "IsListInit/IsInitListCopy must come with a single initializer list "
3990 "argument.");
3991 InitListExpr *ILE =
3992 (IsListInit || IsInitListCopy) ? cast<InitListExpr>(Args[0]) : nullptr;
3993 MultiExprArg UnwrappedArgs =
3994 ILE ? MultiExprArg(ILE->getInits(), ILE->getNumInits()) : Args;
3995
3996 // The type we're constructing needs to be complete.
3997 if (!S.isCompleteType(Kind.getLocation(), DestType)) {
3998 Sequence.setIncompleteTypeFailure(DestType);
3999 return;
4000 }
4001
4002 // C++17 [dcl.init]p17:
4003 // - If the initializer expression is a prvalue and the cv-unqualified
4004 // version of the source type is the same class as the class of the
4005 // destination, the initializer expression is used to initialize the
4006 // destination object.
4007 // Per DR (no number yet), this does not apply when initializing a base
4008 // class or delegating to another constructor from a mem-initializer.
4009 // ObjC++: Lambda captured by the block in the lambda to block conversion
4010 // should avoid copy elision.
4011 if (S.getLangOpts().CPlusPlus17 &&
4012 Entity.getKind() != InitializedEntity::EK_Base &&
4013 Entity.getKind() != InitializedEntity::EK_Delegating &&
4014 Entity.getKind() !=
4015 InitializedEntity::EK_LambdaToBlockConversionBlockElement &&
4016 UnwrappedArgs.size() == 1 && UnwrappedArgs[0]->isRValue() &&
4017 S.Context.hasSameUnqualifiedType(UnwrappedArgs[0]->getType(), DestType)) {
4018 // Convert qualifications if necessary.
4019 Sequence.AddQualificationConversionStep(DestType, VK_RValue);
4020 if (ILE)
4021 Sequence.RewrapReferenceInitList(DestType, ILE);
4022 return;
4023 }
4024
4025 const RecordType *DestRecordType = DestType->getAs<RecordType>();
4026 assert(DestRecordType && "Constructor initialization requires record type");
4027 CXXRecordDecl *DestRecordDecl
4028 = cast<CXXRecordDecl>(DestRecordType->getDecl());
4029
4030 // Build the candidate set directly in the initialization sequence
4031 // structure, so that it will persist if we fail.
4032 OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
4033
4034 // Determine whether we are allowed to call explicit constructors or
4035 // explicit conversion operators.
4036 bool AllowExplicit = Kind.AllowExplicit() || IsListInit;
4037 bool CopyInitialization = Kind.getKind() == InitializationKind::IK_Copy;
4038
4039 // - Otherwise, if T is a class type, constructors are considered. The
4040 // applicable constructors are enumerated, and the best one is chosen
4041 // through overload resolution.
4042 DeclContext::lookup_result Ctors = S.LookupConstructors(DestRecordDecl);
4043
4044 OverloadingResult Result = OR_No_Viable_Function;
4045 OverloadCandidateSet::iterator Best;
4046 bool AsInitializerList = false;
4047
4048 // C++11 [over.match.list]p1, per DR1467:
4049 // When objects of non-aggregate type T are list-initialized, such that
4050 // 8.5.4 [dcl.init.list] specifies that overload resolution is performed
4051 // according to the rules in this section, overload resolution selects
4052 // the constructor in two phases:
4053 //
4054 // - Initially, the candidate functions are the initializer-list
4055 // constructors of the class T and the argument list consists of the
4056 // initializer list as a single argument.
4057 if (IsListInit) {
4058 AsInitializerList = true;
4059
4060 // If the initializer list has no elements and T has a default constructor,
4061 // the first phase is omitted.
4062 if (!(UnwrappedArgs.empty() && S.LookupDefaultConstructor(DestRecordDecl)))
4063 Result = ResolveConstructorOverload(S, Kind.getLocation(), Args,
4064 CandidateSet, DestType, Ctors, Best,
4065 CopyInitialization, AllowExplicit,
4066 /*OnlyListConstructors=*/true,
4067 IsListInit);
4068 }
4069
4070 // C++11 [over.match.list]p1:
4071 // - If no viable initializer-list constructor is found, overload resolution
4072 // is performed again, where the candidate functions are all the
4073 // constructors of the class T and the argument list consists of the
4074 // elements of the initializer list.
4075 if (Result == OR_No_Viable_Function) {
4076 AsInitializerList = false;
4077 Result = ResolveConstructorOverload(S, Kind.getLocation(), UnwrappedArgs,
4078 CandidateSet, DestType, Ctors, Best,
4079 CopyInitialization, AllowExplicit,
4080 /*OnlyListConstructors=*/false,
4081 IsListInit);
4082 }
4083 if (Result) {
4084 Sequence.SetOverloadFailure(IsListInit ?
4085 InitializationSequence::FK_ListConstructorOverloadFailed :
4086 InitializationSequence::FK_ConstructorOverloadFailed,
4087 Result);
4088 return;
4089 }
4090
4091 bool HadMultipleCandidates = (CandidateSet.size() > 1);
4092
4093 // In C++17, ResolveConstructorOverload can select a conversion function
4094 // instead of a constructor.
4095 if (auto *CD = dyn_cast<CXXConversionDecl>(Best->Function)) {
4096 // Add the user-defined conversion step that calls the conversion function.
4097 QualType ConvType = CD->getConversionType();
4098 assert(S.Context.hasSameUnqualifiedType(ConvType, DestType) &&
4099 "should not have selected this conversion function");
4100 Sequence.AddUserConversionStep(CD, Best->FoundDecl, ConvType,
4101 HadMultipleCandidates);
4102 if (!S.Context.hasSameType(ConvType, DestType))
4103 Sequence.AddQualificationConversionStep(DestType, VK_RValue);
4104 if (IsListInit)
4105 Sequence.RewrapReferenceInitList(Entity.getType(), ILE);
4106 return;
4107 }
4108
4109 // C++11 [dcl.init]p6:
4110 // If a program calls for the default initialization of an object
4111 // of a const-qualified type T, T shall be a class type with a
4112 // user-provided default constructor.
4113 // C++ core issue 253 proposal:
4114 // If the implicit default constructor initializes all subobjects, no
4115 // initializer should be required.
4116 // The 253 proposal is for example needed to process libstdc++ headers in 5.x.
4117 CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
4118 if (Kind.getKind() == InitializationKind::IK_Default &&
4119 Entity.getType().isConstQualified()) {
4120 if (!CtorDecl->getParent()->allowConstDefaultInit()) {
4121 if (!maybeRecoverWithZeroInitialization(S, Sequence, Entity))
4122 Sequence.SetFailed(InitializationSequence::FK_DefaultInitOfConst);
4123 return;
4124 }
4125 }
4126
4127 // C++11 [over.match.list]p1:
4128 // In copy-list-initialization, if an explicit constructor is chosen, the
4129 // initializer is ill-formed.
4130 if (IsListInit && !Kind.AllowExplicit() && CtorDecl->isExplicit()) {
4131 Sequence.SetFailed(InitializationSequence::FK_ExplicitConstructor);
4132 return;
4133 }
4134
4135 // Add the constructor initialization step. Any cv-qualification conversion is
4136 // subsumed by the initialization.
4137 Sequence.AddConstructorInitializationStep(
4138 Best->FoundDecl, CtorDecl, DestArrayType, HadMultipleCandidates,
4139 IsListInit | IsInitListCopy, AsInitializerList);
4140 }
4141
4142 static bool
ResolveOverloadedFunctionForReferenceBinding(Sema & S,Expr * Initializer,QualType & SourceType,QualType & UnqualifiedSourceType,QualType UnqualifiedTargetType,InitializationSequence & Sequence)4143 ResolveOverloadedFunctionForReferenceBinding(Sema &S,
4144 Expr *Initializer,
4145 QualType &SourceType,
4146 QualType &UnqualifiedSourceType,
4147 QualType UnqualifiedTargetType,
4148 InitializationSequence &Sequence) {
4149 if (S.Context.getCanonicalType(UnqualifiedSourceType) ==
4150 S.Context.OverloadTy) {
4151 DeclAccessPair Found;
4152 bool HadMultipleCandidates = false;
4153 if (FunctionDecl *Fn
4154 = S.ResolveAddressOfOverloadedFunction(Initializer,
4155 UnqualifiedTargetType,
4156 false, Found,
4157 &HadMultipleCandidates)) {
4158 Sequence.AddAddressOverloadResolutionStep(Fn, Found,
4159 HadMultipleCandidates);
4160 SourceType = Fn->getType();
4161 UnqualifiedSourceType = SourceType.getUnqualifiedType();
4162 } else if (!UnqualifiedTargetType->isRecordType()) {
4163 Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
4164 return true;
4165 }
4166 }
4167 return false;
4168 }
4169
4170 static void TryReferenceInitializationCore(Sema &S,
4171 const InitializedEntity &Entity,
4172 const InitializationKind &Kind,
4173 Expr *Initializer,
4174 QualType cv1T1, QualType T1,
4175 Qualifiers T1Quals,
4176 QualType cv2T2, QualType T2,
4177 Qualifiers T2Quals,
4178 InitializationSequence &Sequence);
4179
4180 static void TryValueInitialization(Sema &S,
4181 const InitializedEntity &Entity,
4182 const InitializationKind &Kind,
4183 InitializationSequence &Sequence,
4184 InitListExpr *InitList = nullptr);
4185
4186 /// Attempt list initialization of a reference.
TryReferenceListInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,InitListExpr * InitList,InitializationSequence & Sequence,bool TreatUnavailableAsInvalid)4187 static void TryReferenceListInitialization(Sema &S,
4188 const InitializedEntity &Entity,
4189 const InitializationKind &Kind,
4190 InitListExpr *InitList,
4191 InitializationSequence &Sequence,
4192 bool TreatUnavailableAsInvalid) {
4193 // First, catch C++03 where this isn't possible.
4194 if (!S.getLangOpts().CPlusPlus11) {
4195 Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
4196 return;
4197 }
4198 // Can't reference initialize a compound literal.
4199 if (Entity.getKind() == InitializedEntity::EK_CompoundLiteralInit) {
4200 Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
4201 return;
4202 }
4203
4204 QualType DestType = Entity.getType();
4205 QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
4206 Qualifiers T1Quals;
4207 QualType T1 = S.Context.getUnqualifiedArrayType(cv1T1, T1Quals);
4208
4209 // Reference initialization via an initializer list works thus:
4210 // If the initializer list consists of a single element that is
4211 // reference-related to the referenced type, bind directly to that element
4212 // (possibly creating temporaries).
4213 // Otherwise, initialize a temporary with the initializer list and
4214 // bind to that.
4215 if (InitList->getNumInits() == 1) {
4216 Expr *Initializer = InitList->getInit(0);
4217 QualType cv2T2 = Initializer->getType();
4218 Qualifiers T2Quals;
4219 QualType T2 = S.Context.getUnqualifiedArrayType(cv2T2, T2Quals);
4220
4221 // If this fails, creating a temporary wouldn't work either.
4222 if (ResolveOverloadedFunctionForReferenceBinding(S, Initializer, cv2T2, T2,
4223 T1, Sequence))
4224 return;
4225
4226 SourceLocation DeclLoc = Initializer->getBeginLoc();
4227 Sema::ReferenceCompareResult RefRelationship
4228 = S.CompareReferenceRelationship(DeclLoc, cv1T1, cv2T2);
4229 if (RefRelationship >= Sema::Ref_Related) {
4230 // Try to bind the reference here.
4231 TryReferenceInitializationCore(S, Entity, Kind, Initializer, cv1T1, T1,
4232 T1Quals, cv2T2, T2, T2Quals, Sequence);
4233 if (Sequence)
4234 Sequence.RewrapReferenceInitList(cv1T1, InitList);
4235 return;
4236 }
4237
4238 // Update the initializer if we've resolved an overloaded function.
4239 if (Sequence.step_begin() != Sequence.step_end())
4240 Sequence.RewrapReferenceInitList(cv1T1, InitList);
4241 }
4242
4243 // Not reference-related. Create a temporary and bind to that.
4244 InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(cv1T1);
4245
4246 TryListInitialization(S, TempEntity, Kind, InitList, Sequence,
4247 TreatUnavailableAsInvalid);
4248 if (Sequence) {
4249 if (DestType->isRValueReferenceType() ||
4250 (T1Quals.hasConst() && !T1Quals.hasVolatile()))
4251 Sequence.AddReferenceBindingStep(cv1T1, /*BindingTemporary=*/true);
4252 else
4253 Sequence.SetFailed(
4254 InitializationSequence::FK_NonConstLValueReferenceBindingToTemporary);
4255 }
4256 }
4257
4258 /// Attempt list initialization (C++0x [dcl.init.list])
TryListInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,InitListExpr * InitList,InitializationSequence & Sequence,bool TreatUnavailableAsInvalid)4259 static void TryListInitialization(Sema &S,
4260 const InitializedEntity &Entity,
4261 const InitializationKind &Kind,
4262 InitListExpr *InitList,
4263 InitializationSequence &Sequence,
4264 bool TreatUnavailableAsInvalid) {
4265 QualType DestType = Entity.getType();
4266
4267 // C++ doesn't allow scalar initialization with more than one argument.
4268 // But C99 complex numbers are scalars and it makes sense there.
4269 if (S.getLangOpts().CPlusPlus && DestType->isScalarType() &&
4270 !DestType->isAnyComplexType() && InitList->getNumInits() > 1) {
4271 Sequence.SetFailed(InitializationSequence::FK_TooManyInitsForScalar);
4272 return;
4273 }
4274 if (DestType->isReferenceType()) {
4275 TryReferenceListInitialization(S, Entity, Kind, InitList, Sequence,
4276 TreatUnavailableAsInvalid);
4277 return;
4278 }
4279
4280 if (DestType->isRecordType() &&
4281 !S.isCompleteType(InitList->getBeginLoc(), DestType)) {
4282 Sequence.setIncompleteTypeFailure(DestType);
4283 return;
4284 }
4285
4286 // C++11 [dcl.init.list]p3, per DR1467:
4287 // - If T is a class type and the initializer list has a single element of
4288 // type cv U, where U is T or a class derived from T, the object is
4289 // initialized from that element (by copy-initialization for
4290 // copy-list-initialization, or by direct-initialization for
4291 // direct-list-initialization).
4292 // - Otherwise, if T is a character array and the initializer list has a
4293 // single element that is an appropriately-typed string literal
4294 // (8.5.2 [dcl.init.string]), initialization is performed as described
4295 // in that section.
4296 // - Otherwise, if T is an aggregate, [...] (continue below).
4297 if (S.getLangOpts().CPlusPlus11 && InitList->getNumInits() == 1) {
4298 if (DestType->isRecordType()) {
4299 QualType InitType = InitList->getInit(0)->getType();
4300 if (S.Context.hasSameUnqualifiedType(InitType, DestType) ||
4301 S.IsDerivedFrom(InitList->getBeginLoc(), InitType, DestType)) {
4302 Expr *InitListAsExpr = InitList;
4303 TryConstructorInitialization(S, Entity, Kind, InitListAsExpr, DestType,
4304 DestType, Sequence,
4305 /*InitListSyntax*/false,
4306 /*IsInitListCopy*/true);
4307 return;
4308 }
4309 }
4310 if (const ArrayType *DestAT = S.Context.getAsArrayType(DestType)) {
4311 Expr *SubInit[1] = {InitList->getInit(0)};
4312 if (!isa<VariableArrayType>(DestAT) &&
4313 IsStringInit(SubInit[0], DestAT, S.Context) == SIF_None) {
4314 InitializationKind SubKind =
4315 Kind.getKind() == InitializationKind::IK_DirectList
4316 ? InitializationKind::CreateDirect(Kind.getLocation(),
4317 InitList->getLBraceLoc(),
4318 InitList->getRBraceLoc())
4319 : Kind;
4320 Sequence.InitializeFrom(S, Entity, SubKind, SubInit,
4321 /*TopLevelOfInitList*/ true,
4322 TreatUnavailableAsInvalid);
4323
4324 // TryStringLiteralInitialization() (in InitializeFrom()) will fail if
4325 // the element is not an appropriately-typed string literal, in which
4326 // case we should proceed as in C++11 (below).
4327 if (Sequence) {
4328 Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
4329 return;
4330 }
4331 }
4332 }
4333 }
4334
4335 // C++11 [dcl.init.list]p3:
4336 // - If T is an aggregate, aggregate initialization is performed.
4337 if ((DestType->isRecordType() && !DestType->isAggregateType()) ||
4338 (S.getLangOpts().CPlusPlus11 &&
4339 S.isStdInitializerList(DestType, nullptr))) {
4340 if (S.getLangOpts().CPlusPlus11) {
4341 // - Otherwise, if the initializer list has no elements and T is a
4342 // class type with a default constructor, the object is
4343 // value-initialized.
4344 if (InitList->getNumInits() == 0) {
4345 CXXRecordDecl *RD = DestType->getAsCXXRecordDecl();
4346 if (S.LookupDefaultConstructor(RD)) {
4347 TryValueInitialization(S, Entity, Kind, Sequence, InitList);
4348 return;
4349 }
4350 }
4351
4352 // - Otherwise, if T is a specialization of std::initializer_list<E>,
4353 // an initializer_list object constructed [...]
4354 if (TryInitializerListConstruction(S, InitList, DestType, Sequence,
4355 TreatUnavailableAsInvalid))
4356 return;
4357
4358 // - Otherwise, if T is a class type, constructors are considered.
4359 Expr *InitListAsExpr = InitList;
4360 TryConstructorInitialization(S, Entity, Kind, InitListAsExpr, DestType,
4361 DestType, Sequence, /*InitListSyntax*/true);
4362 } else
4363 Sequence.SetFailed(InitializationSequence::FK_InitListBadDestinationType);
4364 return;
4365 }
4366
4367 if (S.getLangOpts().CPlusPlus && !DestType->isAggregateType() &&
4368 InitList->getNumInits() == 1) {
4369 Expr *E = InitList->getInit(0);
4370
4371 // - Otherwise, if T is an enumeration with a fixed underlying type,
4372 // the initializer-list has a single element v, and the initialization
4373 // is direct-list-initialization, the object is initialized with the
4374 // value T(v); if a narrowing conversion is required to convert v to
4375 // the underlying type of T, the program is ill-formed.
4376 auto *ET = DestType->getAs<EnumType>();
4377 if (S.getLangOpts().CPlusPlus17 &&
4378 Kind.getKind() == InitializationKind::IK_DirectList &&
4379 ET && ET->getDecl()->isFixed() &&
4380 !S.Context.hasSameUnqualifiedType(E->getType(), DestType) &&
4381 (E->getType()->isIntegralOrEnumerationType() ||
4382 E->getType()->isFloatingType())) {
4383 // There are two ways that T(v) can work when T is an enumeration type.
4384 // If there is either an implicit conversion sequence from v to T or
4385 // a conversion function that can convert from v to T, then we use that.
4386 // Otherwise, if v is of integral, enumeration, or floating-point type,
4387 // it is converted to the enumeration type via its underlying type.
4388 // There is no overlap possible between these two cases (except when the
4389 // source value is already of the destination type), and the first
4390 // case is handled by the general case for single-element lists below.
4391 ImplicitConversionSequence ICS;
4392 ICS.setStandard();
4393 ICS.Standard.setAsIdentityConversion();
4394 if (!E->isRValue())
4395 ICS.Standard.First = ICK_Lvalue_To_Rvalue;
4396 // If E is of a floating-point type, then the conversion is ill-formed
4397 // due to narrowing, but go through the motions in order to produce the
4398 // right diagnostic.
4399 ICS.Standard.Second = E->getType()->isFloatingType()
4400 ? ICK_Floating_Integral
4401 : ICK_Integral_Conversion;
4402 ICS.Standard.setFromType(E->getType());
4403 ICS.Standard.setToType(0, E->getType());
4404 ICS.Standard.setToType(1, DestType);
4405 ICS.Standard.setToType(2, DestType);
4406 Sequence.AddConversionSequenceStep(ICS, ICS.Standard.getToType(2),
4407 /*TopLevelOfInitList*/true);
4408 Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
4409 return;
4410 }
4411
4412 // - Otherwise, if the initializer list has a single element of type E
4413 // [...references are handled above...], the object or reference is
4414 // initialized from that element (by copy-initialization for
4415 // copy-list-initialization, or by direct-initialization for
4416 // direct-list-initialization); if a narrowing conversion is required
4417 // to convert the element to T, the program is ill-formed.
4418 //
4419 // Per core-24034, this is direct-initialization if we were performing
4420 // direct-list-initialization and copy-initialization otherwise.
4421 // We can't use InitListChecker for this, because it always performs
4422 // copy-initialization. This only matters if we might use an 'explicit'
4423 // conversion operator, so we only need to handle the cases where the source
4424 // is of record type.
4425 if (InitList->getInit(0)->getType()->isRecordType()) {
4426 InitializationKind SubKind =
4427 Kind.getKind() == InitializationKind::IK_DirectList
4428 ? InitializationKind::CreateDirect(Kind.getLocation(),
4429 InitList->getLBraceLoc(),
4430 InitList->getRBraceLoc())
4431 : Kind;
4432 Expr *SubInit[1] = { InitList->getInit(0) };
4433 Sequence.InitializeFrom(S, Entity, SubKind, SubInit,
4434 /*TopLevelOfInitList*/true,
4435 TreatUnavailableAsInvalid);
4436 if (Sequence)
4437 Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
4438 return;
4439 }
4440 }
4441
4442 InitListChecker CheckInitList(S, Entity, InitList,
4443 DestType, /*VerifyOnly=*/true, TreatUnavailableAsInvalid);
4444 if (CheckInitList.HadError()) {
4445 Sequence.SetFailed(InitializationSequence::FK_ListInitializationFailed);
4446 return;
4447 }
4448
4449 // Add the list initialization step with the built init list.
4450 Sequence.AddListInitializationStep(DestType);
4451 }
4452
4453 /// Try a reference initialization that involves calling a conversion
4454 /// function.
TryRefInitWithConversionFunction(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,Expr * Initializer,bool AllowRValues,bool IsLValueRef,InitializationSequence & Sequence)4455 static OverloadingResult TryRefInitWithConversionFunction(
4456 Sema &S, const InitializedEntity &Entity, const InitializationKind &Kind,
4457 Expr *Initializer, bool AllowRValues, bool IsLValueRef,
4458 InitializationSequence &Sequence) {
4459 QualType DestType = Entity.getType();
4460 QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
4461 QualType T1 = cv1T1.getUnqualifiedType();
4462 QualType cv2T2 = Initializer->getType();
4463 QualType T2 = cv2T2.getUnqualifiedType();
4464
4465 assert(!S.CompareReferenceRelationship(Initializer->getBeginLoc(), T1, T2) &&
4466 "Must have incompatible references when binding via conversion");
4467
4468 // Build the candidate set directly in the initialization sequence
4469 // structure, so that it will persist if we fail.
4470 OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
4471 CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
4472
4473 // Determine whether we are allowed to call explicit conversion operators.
4474 // Note that none of [over.match.copy], [over.match.conv], nor
4475 // [over.match.ref] permit an explicit constructor to be chosen when
4476 // initializing a reference, not even for direct-initialization.
4477 bool AllowExplicitCtors = false;
4478 bool AllowExplicitConvs = Kind.allowExplicitConversionFunctionsInRefBinding();
4479
4480 const RecordType *T1RecordType = nullptr;
4481 if (AllowRValues && (T1RecordType = T1->getAs<RecordType>()) &&
4482 S.isCompleteType(Kind.getLocation(), T1)) {
4483 // The type we're converting to is a class type. Enumerate its constructors
4484 // to see if there is a suitable conversion.
4485 CXXRecordDecl *T1RecordDecl = cast<CXXRecordDecl>(T1RecordType->getDecl());
4486
4487 for (NamedDecl *D : S.LookupConstructors(T1RecordDecl)) {
4488 auto Info = getConstructorInfo(D);
4489 if (!Info.Constructor)
4490 continue;
4491
4492 if (!Info.Constructor->isInvalidDecl() &&
4493 Info.Constructor->isConvertingConstructor(/*AllowExplicit*/true)) {
4494 if (Info.ConstructorTmpl)
4495 S.AddTemplateOverloadCandidate(
4496 Info.ConstructorTmpl, Info.FoundDecl,
4497 /*ExplicitArgs*/ nullptr, Initializer, CandidateSet,
4498 /*SuppressUserConversions=*/true,
4499 /*PartialOverloading*/ false, AllowExplicitCtors);
4500 else
4501 S.AddOverloadCandidate(
4502 Info.Constructor, Info.FoundDecl, Initializer, CandidateSet,
4503 /*SuppressUserConversions=*/true,
4504 /*PartialOverloading*/ false, AllowExplicitCtors);
4505 }
4506 }
4507 }
4508 if (T1RecordType && T1RecordType->getDecl()->isInvalidDecl())
4509 return OR_No_Viable_Function;
4510
4511 const RecordType *T2RecordType = nullptr;
4512 if ((T2RecordType = T2->getAs<RecordType>()) &&
4513 S.isCompleteType(Kind.getLocation(), T2)) {
4514 // The type we're converting from is a class type, enumerate its conversion
4515 // functions.
4516 CXXRecordDecl *T2RecordDecl = cast<CXXRecordDecl>(T2RecordType->getDecl());
4517
4518 const auto &Conversions = T2RecordDecl->getVisibleConversionFunctions();
4519 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
4520 NamedDecl *D = *I;
4521 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
4522 if (isa<UsingShadowDecl>(D))
4523 D = cast<UsingShadowDecl>(D)->getTargetDecl();
4524
4525 FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
4526 CXXConversionDecl *Conv;
4527 if (ConvTemplate)
4528 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
4529 else
4530 Conv = cast<CXXConversionDecl>(D);
4531
4532 // If the conversion function doesn't return a reference type,
4533 // it can't be considered for this conversion unless we're allowed to
4534 // consider rvalues.
4535 // FIXME: Do we need to make sure that we only consider conversion
4536 // candidates with reference-compatible results? That might be needed to
4537 // break recursion.
4538 if ((AllowRValues ||
4539 Conv->getConversionType()->isLValueReferenceType())) {
4540 if (ConvTemplate)
4541 S.AddTemplateConversionCandidate(
4542 ConvTemplate, I.getPair(), ActingDC, Initializer, DestType,
4543 CandidateSet,
4544 /*AllowObjCConversionOnExplicit=*/false, AllowExplicitConvs);
4545 else
4546 S.AddConversionCandidate(
4547 Conv, I.getPair(), ActingDC, Initializer, DestType, CandidateSet,
4548 /*AllowObjCConversionOnExplicit=*/false, AllowExplicitConvs);
4549 }
4550 }
4551 }
4552 if (T2RecordType && T2RecordType->getDecl()->isInvalidDecl())
4553 return OR_No_Viable_Function;
4554
4555 SourceLocation DeclLoc = Initializer->getBeginLoc();
4556
4557 // Perform overload resolution. If it fails, return the failed result.
4558 OverloadCandidateSet::iterator Best;
4559 if (OverloadingResult Result
4560 = CandidateSet.BestViableFunction(S, DeclLoc, Best))
4561 return Result;
4562
4563 FunctionDecl *Function = Best->Function;
4564 // This is the overload that will be used for this initialization step if we
4565 // use this initialization. Mark it as referenced.
4566 Function->setReferenced();
4567
4568 // Compute the returned type and value kind of the conversion.
4569 QualType cv3T3;
4570 if (isa<CXXConversionDecl>(Function))
4571 cv3T3 = Function->getReturnType();
4572 else
4573 cv3T3 = T1;
4574
4575 ExprValueKind VK = VK_RValue;
4576 if (cv3T3->isLValueReferenceType())
4577 VK = VK_LValue;
4578 else if (const auto *RRef = cv3T3->getAs<RValueReferenceType>())
4579 VK = RRef->getPointeeType()->isFunctionType() ? VK_LValue : VK_XValue;
4580 cv3T3 = cv3T3.getNonLValueExprType(S.Context);
4581
4582 // Add the user-defined conversion step.
4583 bool HadMultipleCandidates = (CandidateSet.size() > 1);
4584 Sequence.AddUserConversionStep(Function, Best->FoundDecl, cv3T3,
4585 HadMultipleCandidates);
4586
4587 // Determine whether we'll need to perform derived-to-base adjustments or
4588 // other conversions.
4589 Sema::ReferenceConversions RefConv;
4590 Sema::ReferenceCompareResult NewRefRelationship =
4591 S.CompareReferenceRelationship(DeclLoc, T1, cv3T3, &RefConv);
4592
4593 // Add the final conversion sequence, if necessary.
4594 if (NewRefRelationship == Sema::Ref_Incompatible) {
4595 assert(!isa<CXXConstructorDecl>(Function) &&
4596 "should not have conversion after constructor");
4597
4598 ImplicitConversionSequence ICS;
4599 ICS.setStandard();
4600 ICS.Standard = Best->FinalConversion;
4601 Sequence.AddConversionSequenceStep(ICS, ICS.Standard.getToType(2));
4602
4603 // Every implicit conversion results in a prvalue, except for a glvalue
4604 // derived-to-base conversion, which we handle below.
4605 cv3T3 = ICS.Standard.getToType(2);
4606 VK = VK_RValue;
4607 }
4608
4609 // If the converted initializer is a prvalue, its type T4 is adjusted to
4610 // type "cv1 T4" and the temporary materialization conversion is applied.
4611 //
4612 // We adjust the cv-qualifications to match the reference regardless of
4613 // whether we have a prvalue so that the AST records the change. In this
4614 // case, T4 is "cv3 T3".
4615 QualType cv1T4 = S.Context.getQualifiedType(cv3T3, cv1T1.getQualifiers());
4616 if (cv1T4.getQualifiers() != cv3T3.getQualifiers())
4617 Sequence.AddQualificationConversionStep(cv1T4, VK);
4618 Sequence.AddReferenceBindingStep(cv1T4, VK == VK_RValue);
4619 VK = IsLValueRef ? VK_LValue : VK_XValue;
4620
4621 if (RefConv & Sema::ReferenceConversions::DerivedToBase)
4622 Sequence.AddDerivedToBaseCastStep(cv1T1, VK);
4623 else if (RefConv & Sema::ReferenceConversions::ObjC)
4624 Sequence.AddObjCObjectConversionStep(cv1T1);
4625 else if (RefConv & Sema::ReferenceConversions::Function)
4626 Sequence.AddQualificationConversionStep(cv1T1, VK);
4627 else if (RefConv & Sema::ReferenceConversions::Qualification) {
4628 if (!S.Context.hasSameType(cv1T4, cv1T1))
4629 Sequence.AddQualificationConversionStep(cv1T1, VK);
4630 }
4631
4632 return OR_Success;
4633 }
4634
4635 static void CheckCXX98CompatAccessibleCopy(Sema &S,
4636 const InitializedEntity &Entity,
4637 Expr *CurInitExpr);
4638
4639 /// Attempt reference initialization (C++0x [dcl.init.ref])
TryReferenceInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,Expr * Initializer,InitializationSequence & Sequence)4640 static void TryReferenceInitialization(Sema &S,
4641 const InitializedEntity &Entity,
4642 const InitializationKind &Kind,
4643 Expr *Initializer,
4644 InitializationSequence &Sequence) {
4645 QualType DestType = Entity.getType();
4646 QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
4647 Qualifiers T1Quals;
4648 QualType T1 = S.Context.getUnqualifiedArrayType(cv1T1, T1Quals);
4649 QualType cv2T2 = Initializer->getType();
4650 Qualifiers T2Quals;
4651 QualType T2 = S.Context.getUnqualifiedArrayType(cv2T2, T2Quals);
4652
4653 // If the initializer is the address of an overloaded function, try
4654 // to resolve the overloaded function. If all goes well, T2 is the
4655 // type of the resulting function.
4656 if (ResolveOverloadedFunctionForReferenceBinding(S, Initializer, cv2T2, T2,
4657 T1, Sequence))
4658 return;
4659
4660 // Delegate everything else to a subfunction.
4661 TryReferenceInitializationCore(S, Entity, Kind, Initializer, cv1T1, T1,
4662 T1Quals, cv2T2, T2, T2Quals, Sequence);
4663 }
4664
4665 /// Determine whether an expression is a non-referenceable glvalue (one to
4666 /// which a reference can never bind). Attempting to bind a reference to
4667 /// such a glvalue will always create a temporary.
isNonReferenceableGLValue(Expr * E)4668 static bool isNonReferenceableGLValue(Expr *E) {
4669 return E->refersToBitField() || E->refersToVectorElement();
4670 }
4671
4672 /// Reference initialization without resolving overloaded functions.
TryReferenceInitializationCore(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,Expr * Initializer,QualType cv1T1,QualType T1,Qualifiers T1Quals,QualType cv2T2,QualType T2,Qualifiers T2Quals,InitializationSequence & Sequence)4673 static void TryReferenceInitializationCore(Sema &S,
4674 const InitializedEntity &Entity,
4675 const InitializationKind &Kind,
4676 Expr *Initializer,
4677 QualType cv1T1, QualType T1,
4678 Qualifiers T1Quals,
4679 QualType cv2T2, QualType T2,
4680 Qualifiers T2Quals,
4681 InitializationSequence &Sequence) {
4682 QualType DestType = Entity.getType();
4683 SourceLocation DeclLoc = Initializer->getBeginLoc();
4684
4685 // Compute some basic properties of the types and the initializer.
4686 bool isLValueRef = DestType->isLValueReferenceType();
4687 bool isRValueRef = !isLValueRef;
4688 Expr::Classification InitCategory = Initializer->Classify(S.Context);
4689
4690 Sema::ReferenceConversions RefConv;
4691 Sema::ReferenceCompareResult RefRelationship =
4692 S.CompareReferenceRelationship(DeclLoc, cv1T1, cv2T2, &RefConv);
4693
4694 // C++0x [dcl.init.ref]p5:
4695 // A reference to type "cv1 T1" is initialized by an expression of type
4696 // "cv2 T2" as follows:
4697 //
4698 // - If the reference is an lvalue reference and the initializer
4699 // expression
4700 // Note the analogous bullet points for rvalue refs to functions. Because
4701 // there are no function rvalues in C++, rvalue refs to functions are treated
4702 // like lvalue refs.
4703 OverloadingResult ConvOvlResult = OR_Success;
4704 bool T1Function = T1->isFunctionType();
4705 if (isLValueRef || T1Function) {
4706 if (InitCategory.isLValue() && !isNonReferenceableGLValue(Initializer) &&
4707 (RefRelationship == Sema::Ref_Compatible ||
4708 (Kind.isCStyleOrFunctionalCast() &&
4709 RefRelationship == Sema::Ref_Related))) {
4710 // - is an lvalue (but is not a bit-field), and "cv1 T1" is
4711 // reference-compatible with "cv2 T2," or
4712 if (RefConv & (Sema::ReferenceConversions::DerivedToBase |
4713 Sema::ReferenceConversions::ObjC)) {
4714 // If we're converting the pointee, add any qualifiers first;
4715 // these qualifiers must all be top-level, so just convert to "cv1 T2".
4716 if (RefConv & (Sema::ReferenceConversions::Qualification))
4717 Sequence.AddQualificationConversionStep(
4718 S.Context.getQualifiedType(T2, T1Quals),
4719 Initializer->getValueKind());
4720 if (RefConv & Sema::ReferenceConversions::DerivedToBase)
4721 Sequence.AddDerivedToBaseCastStep(cv1T1, VK_LValue);
4722 else
4723 Sequence.AddObjCObjectConversionStep(cv1T1);
4724 } else if (RefConv & (Sema::ReferenceConversions::Qualification |
4725 Sema::ReferenceConversions::Function)) {
4726 // Perform a (possibly multi-level) qualification conversion.
4727 // FIXME: Should we use a different step kind for function conversions?
4728 Sequence.AddQualificationConversionStep(cv1T1,
4729 Initializer->getValueKind());
4730 }
4731
4732 // We only create a temporary here when binding a reference to a
4733 // bit-field or vector element. Those cases are't supposed to be
4734 // handled by this bullet, but the outcome is the same either way.
4735 Sequence.AddReferenceBindingStep(cv1T1, false);
4736 return;
4737 }
4738
4739 // - has a class type (i.e., T2 is a class type), where T1 is not
4740 // reference-related to T2, and can be implicitly converted to an
4741 // lvalue of type "cv3 T3," where "cv1 T1" is reference-compatible
4742 // with "cv3 T3" (this conversion is selected by enumerating the
4743 // applicable conversion functions (13.3.1.6) and choosing the best
4744 // one through overload resolution (13.3)),
4745 // If we have an rvalue ref to function type here, the rhs must be
4746 // an rvalue. DR1287 removed the "implicitly" here.
4747 if (RefRelationship == Sema::Ref_Incompatible && T2->isRecordType() &&
4748 (isLValueRef || InitCategory.isRValue())) {
4749 ConvOvlResult = TryRefInitWithConversionFunction(
4750 S, Entity, Kind, Initializer, /*AllowRValues*/ isRValueRef,
4751 /*IsLValueRef*/ isLValueRef, Sequence);
4752 if (ConvOvlResult == OR_Success)
4753 return;
4754 if (ConvOvlResult != OR_No_Viable_Function)
4755 Sequence.SetOverloadFailure(
4756 InitializationSequence::FK_ReferenceInitOverloadFailed,
4757 ConvOvlResult);
4758 }
4759 }
4760
4761 // - Otherwise, the reference shall be an lvalue reference to a
4762 // non-volatile const type (i.e., cv1 shall be const), or the reference
4763 // shall be an rvalue reference.
4764 // For address spaces, we interpret this to mean that an addr space
4765 // of a reference "cv1 T1" is a superset of addr space of "cv2 T2".
4766 if (isLValueRef && !(T1Quals.hasConst() && !T1Quals.hasVolatile() &&
4767 T1Quals.isAddressSpaceSupersetOf(T2Quals))) {
4768 if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy)
4769 Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
4770 else if (ConvOvlResult && !Sequence.getFailedCandidateSet().empty())
4771 Sequence.SetOverloadFailure(
4772 InitializationSequence::FK_ReferenceInitOverloadFailed,
4773 ConvOvlResult);
4774 else if (!InitCategory.isLValue())
4775 Sequence.SetFailed(
4776 T1Quals.isAddressSpaceSupersetOf(T2Quals)
4777 ? InitializationSequence::
4778 FK_NonConstLValueReferenceBindingToTemporary
4779 : InitializationSequence::FK_ReferenceInitDropsQualifiers);
4780 else {
4781 InitializationSequence::FailureKind FK;
4782 switch (RefRelationship) {
4783 case Sema::Ref_Compatible:
4784 if (Initializer->refersToBitField())
4785 FK = InitializationSequence::
4786 FK_NonConstLValueReferenceBindingToBitfield;
4787 else if (Initializer->refersToVectorElement())
4788 FK = InitializationSequence::
4789 FK_NonConstLValueReferenceBindingToVectorElement;
4790 else
4791 llvm_unreachable("unexpected kind of compatible initializer");
4792 break;
4793 case Sema::Ref_Related:
4794 FK = InitializationSequence::FK_ReferenceInitDropsQualifiers;
4795 break;
4796 case Sema::Ref_Incompatible:
4797 FK = InitializationSequence::
4798 FK_NonConstLValueReferenceBindingToUnrelated;
4799 break;
4800 }
4801 Sequence.SetFailed(FK);
4802 }
4803 return;
4804 }
4805
4806 // - If the initializer expression
4807 // - is an
4808 // [<=14] xvalue (but not a bit-field), class prvalue, array prvalue, or
4809 // [1z] rvalue (but not a bit-field) or
4810 // function lvalue and "cv1 T1" is reference-compatible with "cv2 T2"
4811 //
4812 // Note: functions are handled above and below rather than here...
4813 if (!T1Function &&
4814 (RefRelationship == Sema::Ref_Compatible ||
4815 (Kind.isCStyleOrFunctionalCast() &&
4816 RefRelationship == Sema::Ref_Related)) &&
4817 ((InitCategory.isXValue() && !isNonReferenceableGLValue(Initializer)) ||
4818 (InitCategory.isPRValue() &&
4819 (S.getLangOpts().CPlusPlus17 || T2->isRecordType() ||
4820 T2->isArrayType())))) {
4821 ExprValueKind ValueKind = InitCategory.isXValue() ? VK_XValue : VK_RValue;
4822 if (InitCategory.isPRValue() && T2->isRecordType()) {
4823 // The corresponding bullet in C++03 [dcl.init.ref]p5 gives the
4824 // compiler the freedom to perform a copy here or bind to the
4825 // object, while C++0x requires that we bind directly to the
4826 // object. Hence, we always bind to the object without making an
4827 // extra copy. However, in C++03 requires that we check for the
4828 // presence of a suitable copy constructor:
4829 //
4830 // The constructor that would be used to make the copy shall
4831 // be callable whether or not the copy is actually done.
4832 if (!S.getLangOpts().CPlusPlus11 && !S.getLangOpts().MicrosoftExt)
4833 Sequence.AddExtraneousCopyToTemporary(cv2T2);
4834 else if (S.getLangOpts().CPlusPlus11)
4835 CheckCXX98CompatAccessibleCopy(S, Entity, Initializer);
4836 }
4837
4838 // C++1z [dcl.init.ref]/5.2.1.2:
4839 // If the converted initializer is a prvalue, its type T4 is adjusted
4840 // to type "cv1 T4" and the temporary materialization conversion is
4841 // applied.
4842 // Postpone address space conversions to after the temporary materialization
4843 // conversion to allow creating temporaries in the alloca address space.
4844 auto T1QualsIgnoreAS = T1Quals;
4845 auto T2QualsIgnoreAS = T2Quals;
4846 if (T1Quals.getAddressSpace() != T2Quals.getAddressSpace()) {
4847 T1QualsIgnoreAS.removeAddressSpace();
4848 T2QualsIgnoreAS.removeAddressSpace();
4849 }
4850 QualType cv1T4 = S.Context.getQualifiedType(cv2T2, T1QualsIgnoreAS);
4851 if (T1QualsIgnoreAS != T2QualsIgnoreAS)
4852 Sequence.AddQualificationConversionStep(cv1T4, ValueKind);
4853 Sequence.AddReferenceBindingStep(cv1T4, ValueKind == VK_RValue);
4854 ValueKind = isLValueRef ? VK_LValue : VK_XValue;
4855 // Add addr space conversion if required.
4856 if (T1Quals.getAddressSpace() != T2Quals.getAddressSpace()) {
4857 auto T4Quals = cv1T4.getQualifiers();
4858 T4Quals.addAddressSpace(T1Quals.getAddressSpace());
4859 QualType cv1T4WithAS = S.Context.getQualifiedType(T2, T4Quals);
4860 Sequence.AddQualificationConversionStep(cv1T4WithAS, ValueKind);
4861 cv1T4 = cv1T4WithAS;
4862 }
4863
4864 // In any case, the reference is bound to the resulting glvalue (or to
4865 // an appropriate base class subobject).
4866 if (RefConv & Sema::ReferenceConversions::DerivedToBase)
4867 Sequence.AddDerivedToBaseCastStep(cv1T1, ValueKind);
4868 else if (RefConv & Sema::ReferenceConversions::ObjC)
4869 Sequence.AddObjCObjectConversionStep(cv1T1);
4870 else if (RefConv & Sema::ReferenceConversions::Qualification) {
4871 if (!S.Context.hasSameType(cv1T4, cv1T1))
4872 Sequence.AddQualificationConversionStep(cv1T1, ValueKind);
4873 }
4874 return;
4875 }
4876
4877 // - has a class type (i.e., T2 is a class type), where T1 is not
4878 // reference-related to T2, and can be implicitly converted to an
4879 // xvalue, class prvalue, or function lvalue of type "cv3 T3",
4880 // where "cv1 T1" is reference-compatible with "cv3 T3",
4881 //
4882 // DR1287 removes the "implicitly" here.
4883 if (T2->isRecordType()) {
4884 if (RefRelationship == Sema::Ref_Incompatible) {
4885 ConvOvlResult = TryRefInitWithConversionFunction(
4886 S, Entity, Kind, Initializer, /*AllowRValues*/ true,
4887 /*IsLValueRef*/ isLValueRef, Sequence);
4888 if (ConvOvlResult)
4889 Sequence.SetOverloadFailure(
4890 InitializationSequence::FK_ReferenceInitOverloadFailed,
4891 ConvOvlResult);
4892
4893 return;
4894 }
4895
4896 if (RefRelationship == Sema::Ref_Compatible &&
4897 isRValueRef && InitCategory.isLValue()) {
4898 Sequence.SetFailed(
4899 InitializationSequence::FK_RValueReferenceBindingToLValue);
4900 return;
4901 }
4902
4903 Sequence.SetFailed(InitializationSequence::FK_ReferenceInitDropsQualifiers);
4904 return;
4905 }
4906
4907 // - Otherwise, a temporary of type "cv1 T1" is created and initialized
4908 // from the initializer expression using the rules for a non-reference
4909 // copy-initialization (8.5). The reference is then bound to the
4910 // temporary. [...]
4911
4912 // Ignore address space of reference type at this point and perform address
4913 // space conversion after the reference binding step.
4914 QualType cv1T1IgnoreAS =
4915 T1Quals.hasAddressSpace()
4916 ? S.Context.getQualifiedType(T1, T1Quals.withoutAddressSpace())
4917 : cv1T1;
4918
4919 InitializedEntity TempEntity =
4920 InitializedEntity::InitializeTemporary(cv1T1IgnoreAS);
4921
4922 // FIXME: Why do we use an implicit conversion here rather than trying
4923 // copy-initialization?
4924 ImplicitConversionSequence ICS
4925 = S.TryImplicitConversion(Initializer, TempEntity.getType(),
4926 /*SuppressUserConversions=*/false,
4927 /*AllowExplicit=*/false,
4928 /*FIXME:InOverloadResolution=*/false,
4929 /*CStyle=*/Kind.isCStyleOrFunctionalCast(),
4930 /*AllowObjCWritebackConversion=*/false);
4931
4932 if (ICS.isBad()) {
4933 // FIXME: Use the conversion function set stored in ICS to turn
4934 // this into an overloading ambiguity diagnostic. However, we need
4935 // to keep that set as an OverloadCandidateSet rather than as some
4936 // other kind of set.
4937 if (ConvOvlResult && !Sequence.getFailedCandidateSet().empty())
4938 Sequence.SetOverloadFailure(
4939 InitializationSequence::FK_ReferenceInitOverloadFailed,
4940 ConvOvlResult);
4941 else if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy)
4942 Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
4943 else
4944 Sequence.SetFailed(InitializationSequence::FK_ReferenceInitFailed);
4945 return;
4946 } else {
4947 Sequence.AddConversionSequenceStep(ICS, TempEntity.getType());
4948 }
4949
4950 // [...] If T1 is reference-related to T2, cv1 must be the
4951 // same cv-qualification as, or greater cv-qualification
4952 // than, cv2; otherwise, the program is ill-formed.
4953 unsigned T1CVRQuals = T1Quals.getCVRQualifiers();
4954 unsigned T2CVRQuals = T2Quals.getCVRQualifiers();
4955 if ((RefRelationship == Sema::Ref_Related &&
4956 (T1CVRQuals | T2CVRQuals) != T1CVRQuals) ||
4957 !T1Quals.isAddressSpaceSupersetOf(T2Quals)) {
4958 Sequence.SetFailed(InitializationSequence::FK_ReferenceInitDropsQualifiers);
4959 return;
4960 }
4961
4962 // [...] If T1 is reference-related to T2 and the reference is an rvalue
4963 // reference, the initializer expression shall not be an lvalue.
4964 if (RefRelationship >= Sema::Ref_Related && !isLValueRef &&
4965 InitCategory.isLValue()) {
4966 Sequence.SetFailed(
4967 InitializationSequence::FK_RValueReferenceBindingToLValue);
4968 return;
4969 }
4970
4971 Sequence.AddReferenceBindingStep(cv1T1IgnoreAS, /*BindingTemporary=*/true);
4972
4973 if (T1Quals.hasAddressSpace()) {
4974 if (!Qualifiers::isAddressSpaceSupersetOf(T1Quals.getAddressSpace(),
4975 LangAS::Default)) {
4976 Sequence.SetFailed(
4977 InitializationSequence::FK_ReferenceAddrspaceMismatchTemporary);
4978 return;
4979 }
4980 Sequence.AddQualificationConversionStep(cv1T1, isLValueRef ? VK_LValue
4981 : VK_XValue);
4982 }
4983 }
4984
4985 /// Attempt character array initialization from a string literal
4986 /// (C++ [dcl.init.string], C99 6.7.8).
TryStringLiteralInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,Expr * Initializer,InitializationSequence & Sequence)4987 static void TryStringLiteralInitialization(Sema &S,
4988 const InitializedEntity &Entity,
4989 const InitializationKind &Kind,
4990 Expr *Initializer,
4991 InitializationSequence &Sequence) {
4992 Sequence.AddStringInitStep(Entity.getType());
4993 }
4994
4995 /// Attempt value initialization (C++ [dcl.init]p7).
TryValueInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,InitializationSequence & Sequence,InitListExpr * InitList)4996 static void TryValueInitialization(Sema &S,
4997 const InitializedEntity &Entity,
4998 const InitializationKind &Kind,
4999 InitializationSequence &Sequence,
5000 InitListExpr *InitList) {
5001 assert((!InitList || InitList->getNumInits() == 0) &&
5002 "Shouldn't use value-init for non-empty init lists");
5003
5004 // C++98 [dcl.init]p5, C++11 [dcl.init]p7:
5005 //
5006 // To value-initialize an object of type T means:
5007 QualType T = Entity.getType();
5008
5009 // -- if T is an array type, then each element is value-initialized;
5010 T = S.Context.getBaseElementType(T);
5011
5012 if (const RecordType *RT = T->getAs<RecordType>()) {
5013 if (CXXRecordDecl *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
5014 bool NeedZeroInitialization = true;
5015 // C++98:
5016 // -- if T is a class type (clause 9) with a user-declared constructor
5017 // (12.1), then the default constructor for T is called (and the
5018 // initialization is ill-formed if T has no accessible default
5019 // constructor);
5020 // C++11:
5021 // -- if T is a class type (clause 9) with either no default constructor
5022 // (12.1 [class.ctor]) or a default constructor that is user-provided
5023 // or deleted, then the object is default-initialized;
5024 //
5025 // Note that the C++11 rule is the same as the C++98 rule if there are no
5026 // defaulted or deleted constructors, so we just use it unconditionally.
5027 CXXConstructorDecl *CD = S.LookupDefaultConstructor(ClassDecl);
5028 if (!CD || !CD->getCanonicalDecl()->isDefaulted() || CD->isDeleted())
5029 NeedZeroInitialization = false;
5030
5031 // -- if T is a (possibly cv-qualified) non-union class type without a
5032 // user-provided or deleted default constructor, then the object is
5033 // zero-initialized and, if T has a non-trivial default constructor,
5034 // default-initialized;
5035 // The 'non-union' here was removed by DR1502. The 'non-trivial default
5036 // constructor' part was removed by DR1507.
5037 if (NeedZeroInitialization)
5038 Sequence.AddZeroInitializationStep(Entity.getType());
5039
5040 // C++03:
5041 // -- if T is a non-union class type without a user-declared constructor,
5042 // then every non-static data member and base class component of T is
5043 // value-initialized;
5044 // [...] A program that calls for [...] value-initialization of an
5045 // entity of reference type is ill-formed.
5046 //
5047 // C++11 doesn't need this handling, because value-initialization does not
5048 // occur recursively there, and the implicit default constructor is
5049 // defined as deleted in the problematic cases.
5050 if (!S.getLangOpts().CPlusPlus11 &&
5051 ClassDecl->hasUninitializedReferenceMember()) {
5052 Sequence.SetFailed(InitializationSequence::FK_TooManyInitsForReference);
5053 return;
5054 }
5055
5056 // If this is list-value-initialization, pass the empty init list on when
5057 // building the constructor call. This affects the semantics of a few
5058 // things (such as whether an explicit default constructor can be called).
5059 Expr *InitListAsExpr = InitList;
5060 MultiExprArg Args(&InitListAsExpr, InitList ? 1 : 0);
5061 bool InitListSyntax = InitList;
5062
5063 // FIXME: Instead of creating a CXXConstructExpr of array type here,
5064 // wrap a class-typed CXXConstructExpr in an ArrayInitLoopExpr.
5065 return TryConstructorInitialization(
5066 S, Entity, Kind, Args, T, Entity.getType(), Sequence, InitListSyntax);
5067 }
5068 }
5069
5070 Sequence.AddZeroInitializationStep(Entity.getType());
5071 }
5072
5073 /// Attempt default initialization (C++ [dcl.init]p6).
TryDefaultInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,InitializationSequence & Sequence)5074 static void TryDefaultInitialization(Sema &S,
5075 const InitializedEntity &Entity,
5076 const InitializationKind &Kind,
5077 InitializationSequence &Sequence) {
5078 assert(Kind.getKind() == InitializationKind::IK_Default);
5079
5080 // C++ [dcl.init]p6:
5081 // To default-initialize an object of type T means:
5082 // - if T is an array type, each element is default-initialized;
5083 QualType DestType = S.Context.getBaseElementType(Entity.getType());
5084
5085 // - if T is a (possibly cv-qualified) class type (Clause 9), the default
5086 // constructor for T is called (and the initialization is ill-formed if
5087 // T has no accessible default constructor);
5088 if (DestType->isRecordType() && S.getLangOpts().CPlusPlus) {
5089 TryConstructorInitialization(S, Entity, Kind, None, DestType,
5090 Entity.getType(), Sequence);
5091 return;
5092 }
5093
5094 // - otherwise, no initialization is performed.
5095
5096 // If a program calls for the default initialization of an object of
5097 // a const-qualified type T, T shall be a class type with a user-provided
5098 // default constructor.
5099 if (DestType.isConstQualified() && S.getLangOpts().CPlusPlus) {
5100 if (!maybeRecoverWithZeroInitialization(S, Sequence, Entity))
5101 Sequence.SetFailed(InitializationSequence::FK_DefaultInitOfConst);
5102 return;
5103 }
5104
5105 // If the destination type has a lifetime property, zero-initialize it.
5106 if (DestType.getQualifiers().hasObjCLifetime()) {
5107 Sequence.AddZeroInitializationStep(Entity.getType());
5108 return;
5109 }
5110 }
5111
5112 /// Attempt a user-defined conversion between two types (C++ [dcl.init]),
5113 /// which enumerates all conversion functions and performs overload resolution
5114 /// to select the best.
TryUserDefinedConversion(Sema & S,QualType DestType,const InitializationKind & Kind,Expr * Initializer,InitializationSequence & Sequence,bool TopLevelOfInitList)5115 static void TryUserDefinedConversion(Sema &S,
5116 QualType DestType,
5117 const InitializationKind &Kind,
5118 Expr *Initializer,
5119 InitializationSequence &Sequence,
5120 bool TopLevelOfInitList) {
5121 assert(!DestType->isReferenceType() && "References are handled elsewhere");
5122 QualType SourceType = Initializer->getType();
5123 assert((DestType->isRecordType() || SourceType->isRecordType()) &&
5124 "Must have a class type to perform a user-defined conversion");
5125
5126 // Build the candidate set directly in the initialization sequence
5127 // structure, so that it will persist if we fail.
5128 OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
5129 CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
5130 CandidateSet.setDestAS(DestType.getQualifiers().getAddressSpace());
5131
5132 // Determine whether we are allowed to call explicit constructors or
5133 // explicit conversion operators.
5134 bool AllowExplicit = Kind.AllowExplicit();
5135
5136 if (const RecordType *DestRecordType = DestType->getAs<RecordType>()) {
5137 // The type we're converting to is a class type. Enumerate its constructors
5138 // to see if there is a suitable conversion.
5139 CXXRecordDecl *DestRecordDecl
5140 = cast<CXXRecordDecl>(DestRecordType->getDecl());
5141
5142 // Try to complete the type we're converting to.
5143 if (S.isCompleteType(Kind.getLocation(), DestType)) {
5144 for (NamedDecl *D : S.LookupConstructors(DestRecordDecl)) {
5145 auto Info = getConstructorInfo(D);
5146 if (!Info.Constructor)
5147 continue;
5148
5149 if (!Info.Constructor->isInvalidDecl() &&
5150 Info.Constructor->isConvertingConstructor(/*AllowExplicit*/true)) {
5151 if (Info.ConstructorTmpl)
5152 S.AddTemplateOverloadCandidate(
5153 Info.ConstructorTmpl, Info.FoundDecl,
5154 /*ExplicitArgs*/ nullptr, Initializer, CandidateSet,
5155 /*SuppressUserConversions=*/true,
5156 /*PartialOverloading*/ false, AllowExplicit);
5157 else
5158 S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl,
5159 Initializer, CandidateSet,
5160 /*SuppressUserConversions=*/true,
5161 /*PartialOverloading*/ false, AllowExplicit);
5162 }
5163 }
5164 }
5165 }
5166
5167 SourceLocation DeclLoc = Initializer->getBeginLoc();
5168
5169 if (const RecordType *SourceRecordType = SourceType->getAs<RecordType>()) {
5170 // The type we're converting from is a class type, enumerate its conversion
5171 // functions.
5172
5173 // We can only enumerate the conversion functions for a complete type; if
5174 // the type isn't complete, simply skip this step.
5175 if (S.isCompleteType(DeclLoc, SourceType)) {
5176 CXXRecordDecl *SourceRecordDecl
5177 = cast<CXXRecordDecl>(SourceRecordType->getDecl());
5178
5179 const auto &Conversions =
5180 SourceRecordDecl->getVisibleConversionFunctions();
5181 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
5182 NamedDecl *D = *I;
5183 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
5184 if (isa<UsingShadowDecl>(D))
5185 D = cast<UsingShadowDecl>(D)->getTargetDecl();
5186
5187 FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
5188 CXXConversionDecl *Conv;
5189 if (ConvTemplate)
5190 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
5191 else
5192 Conv = cast<CXXConversionDecl>(D);
5193
5194 if (ConvTemplate)
5195 S.AddTemplateConversionCandidate(
5196 ConvTemplate, I.getPair(), ActingDC, Initializer, DestType,
5197 CandidateSet, AllowExplicit, AllowExplicit);
5198 else
5199 S.AddConversionCandidate(Conv, I.getPair(), ActingDC, Initializer,
5200 DestType, CandidateSet, AllowExplicit,
5201 AllowExplicit);
5202 }
5203 }
5204 }
5205
5206 // Perform overload resolution. If it fails, return the failed result.
5207 OverloadCandidateSet::iterator Best;
5208 if (OverloadingResult Result
5209 = CandidateSet.BestViableFunction(S, DeclLoc, Best)) {
5210 Sequence.SetOverloadFailure(
5211 InitializationSequence::FK_UserConversionOverloadFailed,
5212 Result);
5213 return;
5214 }
5215
5216 FunctionDecl *Function = Best->Function;
5217 Function->setReferenced();
5218 bool HadMultipleCandidates = (CandidateSet.size() > 1);
5219
5220 if (isa<CXXConstructorDecl>(Function)) {
5221 // Add the user-defined conversion step. Any cv-qualification conversion is
5222 // subsumed by the initialization. Per DR5, the created temporary is of the
5223 // cv-unqualified type of the destination.
5224 Sequence.AddUserConversionStep(Function, Best->FoundDecl,
5225 DestType.getUnqualifiedType(),
5226 HadMultipleCandidates);
5227
5228 // C++14 and before:
5229 // - if the function is a constructor, the call initializes a temporary
5230 // of the cv-unqualified version of the destination type. The [...]
5231 // temporary [...] is then used to direct-initialize, according to the
5232 // rules above, the object that is the destination of the
5233 // copy-initialization.
5234 // Note that this just performs a simple object copy from the temporary.
5235 //
5236 // C++17:
5237 // - if the function is a constructor, the call is a prvalue of the
5238 // cv-unqualified version of the destination type whose return object
5239 // is initialized by the constructor. The call is used to
5240 // direct-initialize, according to the rules above, the object that
5241 // is the destination of the copy-initialization.
5242 // Therefore we need to do nothing further.
5243 //
5244 // FIXME: Mark this copy as extraneous.
5245 if (!S.getLangOpts().CPlusPlus17)
5246 Sequence.AddFinalCopy(DestType);
5247 else if (DestType.hasQualifiers())
5248 Sequence.AddQualificationConversionStep(DestType, VK_RValue);
5249 return;
5250 }
5251
5252 // Add the user-defined conversion step that calls the conversion function.
5253 QualType ConvType = Function->getCallResultType();
5254 Sequence.AddUserConversionStep(Function, Best->FoundDecl, ConvType,
5255 HadMultipleCandidates);
5256
5257 if (ConvType->getAs<RecordType>()) {
5258 // The call is used to direct-initialize [...] the object that is the
5259 // destination of the copy-initialization.
5260 //
5261 // In C++17, this does not call a constructor if we enter /17.6.1:
5262 // - If the initializer expression is a prvalue and the cv-unqualified
5263 // version of the source type is the same as the class of the
5264 // destination [... do not make an extra copy]
5265 //
5266 // FIXME: Mark this copy as extraneous.
5267 if (!S.getLangOpts().CPlusPlus17 ||
5268 Function->getReturnType()->isReferenceType() ||
5269 !S.Context.hasSameUnqualifiedType(ConvType, DestType))
5270 Sequence.AddFinalCopy(DestType);
5271 else if (!S.Context.hasSameType(ConvType, DestType))
5272 Sequence.AddQualificationConversionStep(DestType, VK_RValue);
5273 return;
5274 }
5275
5276 // If the conversion following the call to the conversion function
5277 // is interesting, add it as a separate step.
5278 if (Best->FinalConversion.First || Best->FinalConversion.Second ||
5279 Best->FinalConversion.Third) {
5280 ImplicitConversionSequence ICS;
5281 ICS.setStandard();
5282 ICS.Standard = Best->FinalConversion;
5283 Sequence.AddConversionSequenceStep(ICS, DestType, TopLevelOfInitList);
5284 }
5285 }
5286
5287 /// An egregious hack for compatibility with libstdc++-4.2: in <tr1/hashtable>,
5288 /// a function with a pointer return type contains a 'return false;' statement.
5289 /// In C++11, 'false' is not a null pointer, so this breaks the build of any
5290 /// code using that header.
5291 ///
5292 /// Work around this by treating 'return false;' as zero-initializing the result
5293 /// if it's used in a pointer-returning function in a system header.
isLibstdcxxPointerReturnFalseHack(Sema & S,const InitializedEntity & Entity,const Expr * Init)5294 static bool isLibstdcxxPointerReturnFalseHack(Sema &S,
5295 const InitializedEntity &Entity,
5296 const Expr *Init) {
5297 return S.getLangOpts().CPlusPlus11 &&
5298 Entity.getKind() == InitializedEntity::EK_Result &&
5299 Entity.getType()->isPointerType() &&
5300 isa<CXXBoolLiteralExpr>(Init) &&
5301 !cast<CXXBoolLiteralExpr>(Init)->getValue() &&
5302 S.getSourceManager().isInSystemHeader(Init->getExprLoc());
5303 }
5304
5305 /// The non-zero enum values here are indexes into diagnostic alternatives.
5306 enum InvalidICRKind { IIK_okay, IIK_nonlocal, IIK_nonscalar };
5307
5308 /// Determines whether this expression is an acceptable ICR source.
isInvalidICRSource(ASTContext & C,Expr * e,bool isAddressOf,bool & isWeakAccess)5309 static InvalidICRKind isInvalidICRSource(ASTContext &C, Expr *e,
5310 bool isAddressOf, bool &isWeakAccess) {
5311 // Skip parens.
5312 e = e->IgnoreParens();
5313
5314 // Skip address-of nodes.
5315 if (UnaryOperator *op = dyn_cast<UnaryOperator>(e)) {
5316 if (op->getOpcode() == UO_AddrOf)
5317 return isInvalidICRSource(C, op->getSubExpr(), /*addressof*/ true,
5318 isWeakAccess);
5319
5320 // Skip certain casts.
5321 } else if (CastExpr *ce = dyn_cast<CastExpr>(e)) {
5322 switch (ce->getCastKind()) {
5323 case CK_Dependent:
5324 case CK_BitCast:
5325 case CK_LValueBitCast:
5326 case CK_NoOp:
5327 return isInvalidICRSource(C, ce->getSubExpr(), isAddressOf, isWeakAccess);
5328
5329 case CK_ArrayToPointerDecay:
5330 return IIK_nonscalar;
5331
5332 case CK_NullToPointer:
5333 return IIK_okay;
5334
5335 default:
5336 break;
5337 }
5338
5339 // If we have a declaration reference, it had better be a local variable.
5340 } else if (isa<DeclRefExpr>(e)) {
5341 // set isWeakAccess to true, to mean that there will be an implicit
5342 // load which requires a cleanup.
5343 if (e->getType().getObjCLifetime() == Qualifiers::OCL_Weak)
5344 isWeakAccess = true;
5345
5346 if (!isAddressOf) return IIK_nonlocal;
5347
5348 VarDecl *var = dyn_cast<VarDecl>(cast<DeclRefExpr>(e)->getDecl());
5349 if (!var) return IIK_nonlocal;
5350
5351 return (var->hasLocalStorage() ? IIK_okay : IIK_nonlocal);
5352
5353 // If we have a conditional operator, check both sides.
5354 } else if (ConditionalOperator *cond = dyn_cast<ConditionalOperator>(e)) {
5355 if (InvalidICRKind iik = isInvalidICRSource(C, cond->getLHS(), isAddressOf,
5356 isWeakAccess))
5357 return iik;
5358
5359 return isInvalidICRSource(C, cond->getRHS(), isAddressOf, isWeakAccess);
5360
5361 // These are never scalar.
5362 } else if (isa<ArraySubscriptExpr>(e)) {
5363 return IIK_nonscalar;
5364
5365 // Otherwise, it needs to be a null pointer constant.
5366 } else {
5367 return (e->isNullPointerConstant(C, Expr::NPC_ValueDependentIsNull)
5368 ? IIK_okay : IIK_nonlocal);
5369 }
5370
5371 return IIK_nonlocal;
5372 }
5373
5374 /// Check whether the given expression is a valid operand for an
5375 /// indirect copy/restore.
checkIndirectCopyRestoreSource(Sema & S,Expr * src)5376 static void checkIndirectCopyRestoreSource(Sema &S, Expr *src) {
5377 assert(src->isRValue());
5378 bool isWeakAccess = false;
5379 InvalidICRKind iik = isInvalidICRSource(S.Context, src, false, isWeakAccess);
5380 // If isWeakAccess to true, there will be an implicit
5381 // load which requires a cleanup.
5382 if (S.getLangOpts().ObjCAutoRefCount && isWeakAccess)
5383 S.Cleanup.setExprNeedsCleanups(true);
5384
5385 if (iik == IIK_okay) return;
5386
5387 S.Diag(src->getExprLoc(), diag::err_arc_nonlocal_writeback)
5388 << ((unsigned) iik - 1) // shift index into diagnostic explanations
5389 << src->getSourceRange();
5390 }
5391
5392 /// Determine whether we have compatible array types for the
5393 /// purposes of GNU by-copy array initialization.
hasCompatibleArrayTypes(ASTContext & Context,const ArrayType * Dest,const ArrayType * Source)5394 static bool hasCompatibleArrayTypes(ASTContext &Context, const ArrayType *Dest,
5395 const ArrayType *Source) {
5396 // If the source and destination array types are equivalent, we're
5397 // done.
5398 if (Context.hasSameType(QualType(Dest, 0), QualType(Source, 0)))
5399 return true;
5400
5401 // Make sure that the element types are the same.
5402 if (!Context.hasSameType(Dest->getElementType(), Source->getElementType()))
5403 return false;
5404
5405 // The only mismatch we allow is when the destination is an
5406 // incomplete array type and the source is a constant array type.
5407 return Source->isConstantArrayType() && Dest->isIncompleteArrayType();
5408 }
5409
tryObjCWritebackConversion(Sema & S,InitializationSequence & Sequence,const InitializedEntity & Entity,Expr * Initializer)5410 static bool tryObjCWritebackConversion(Sema &S,
5411 InitializationSequence &Sequence,
5412 const InitializedEntity &Entity,
5413 Expr *Initializer) {
5414 bool ArrayDecay = false;
5415 QualType ArgType = Initializer->getType();
5416 QualType ArgPointee;
5417 if (const ArrayType *ArgArrayType = S.Context.getAsArrayType(ArgType)) {
5418 ArrayDecay = true;
5419 ArgPointee = ArgArrayType->getElementType();
5420 ArgType = S.Context.getPointerType(ArgPointee);
5421 }
5422
5423 // Handle write-back conversion.
5424 QualType ConvertedArgType;
5425 if (!S.isObjCWritebackConversion(ArgType, Entity.getType(),
5426 ConvertedArgType))
5427 return false;
5428
5429 // We should copy unless we're passing to an argument explicitly
5430 // marked 'out'.
5431 bool ShouldCopy = true;
5432 if (ParmVarDecl *param = cast_or_null<ParmVarDecl>(Entity.getDecl()))
5433 ShouldCopy = (param->getObjCDeclQualifier() != ParmVarDecl::OBJC_TQ_Out);
5434
5435 // Do we need an lvalue conversion?
5436 if (ArrayDecay || Initializer->isGLValue()) {
5437 ImplicitConversionSequence ICS;
5438 ICS.setStandard();
5439 ICS.Standard.setAsIdentityConversion();
5440
5441 QualType ResultType;
5442 if (ArrayDecay) {
5443 ICS.Standard.First = ICK_Array_To_Pointer;
5444 ResultType = S.Context.getPointerType(ArgPointee);
5445 } else {
5446 ICS.Standard.First = ICK_Lvalue_To_Rvalue;
5447 ResultType = Initializer->getType().getNonLValueExprType(S.Context);
5448 }
5449
5450 Sequence.AddConversionSequenceStep(ICS, ResultType);
5451 }
5452
5453 Sequence.AddPassByIndirectCopyRestoreStep(Entity.getType(), ShouldCopy);
5454 return true;
5455 }
5456
TryOCLSamplerInitialization(Sema & S,InitializationSequence & Sequence,QualType DestType,Expr * Initializer)5457 static bool TryOCLSamplerInitialization(Sema &S,
5458 InitializationSequence &Sequence,
5459 QualType DestType,
5460 Expr *Initializer) {
5461 if (!S.getLangOpts().OpenCL || !DestType->isSamplerT() ||
5462 (!Initializer->isIntegerConstantExpr(S.Context) &&
5463 !Initializer->getType()->isSamplerT()))
5464 return false;
5465
5466 Sequence.AddOCLSamplerInitStep(DestType);
5467 return true;
5468 }
5469
IsZeroInitializer(Expr * Initializer,Sema & S)5470 static bool IsZeroInitializer(Expr *Initializer, Sema &S) {
5471 return Initializer->isIntegerConstantExpr(S.getASTContext()) &&
5472 (Initializer->EvaluateKnownConstInt(S.getASTContext()) == 0);
5473 }
5474
TryOCLZeroOpaqueTypeInitialization(Sema & S,InitializationSequence & Sequence,QualType DestType,Expr * Initializer)5475 static bool TryOCLZeroOpaqueTypeInitialization(Sema &S,
5476 InitializationSequence &Sequence,
5477 QualType DestType,
5478 Expr *Initializer) {
5479 if (!S.getLangOpts().OpenCL)
5480 return false;
5481
5482 //
5483 // OpenCL 1.2 spec, s6.12.10
5484 //
5485 // The event argument can also be used to associate the
5486 // async_work_group_copy with a previous async copy allowing
5487 // an event to be shared by multiple async copies; otherwise
5488 // event should be zero.
5489 //
5490 if (DestType->isEventT() || DestType->isQueueT()) {
5491 if (!IsZeroInitializer(Initializer, S))
5492 return false;
5493
5494 Sequence.AddOCLZeroOpaqueTypeStep(DestType);
5495 return true;
5496 }
5497
5498 // We should allow zero initialization for all types defined in the
5499 // cl_intel_device_side_avc_motion_estimation extension, except
5500 // intel_sub_group_avc_mce_payload_t and intel_sub_group_avc_mce_result_t.
5501 if (S.getOpenCLOptions().isEnabled(
5502 "cl_intel_device_side_avc_motion_estimation") &&
5503 DestType->isOCLIntelSubgroupAVCType()) {
5504 if (DestType->isOCLIntelSubgroupAVCMcePayloadType() ||
5505 DestType->isOCLIntelSubgroupAVCMceResultType())
5506 return false;
5507 if (!IsZeroInitializer(Initializer, S))
5508 return false;
5509
5510 Sequence.AddOCLZeroOpaqueTypeStep(DestType);
5511 return true;
5512 }
5513
5514 return false;
5515 }
5516
InitializationSequence(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Args,bool TopLevelOfInitList,bool TreatUnavailableAsInvalid)5517 InitializationSequence::InitializationSequence(Sema &S,
5518 const InitializedEntity &Entity,
5519 const InitializationKind &Kind,
5520 MultiExprArg Args,
5521 bool TopLevelOfInitList,
5522 bool TreatUnavailableAsInvalid)
5523 : FailedCandidateSet(Kind.getLocation(), OverloadCandidateSet::CSK_Normal) {
5524 InitializeFrom(S, Entity, Kind, Args, TopLevelOfInitList,
5525 TreatUnavailableAsInvalid);
5526 }
5527
5528 /// Tries to get a FunctionDecl out of `E`. If it succeeds and we can take the
5529 /// address of that function, this returns true. Otherwise, it returns false.
isExprAnUnaddressableFunction(Sema & S,const Expr * E)5530 static bool isExprAnUnaddressableFunction(Sema &S, const Expr *E) {
5531 auto *DRE = dyn_cast<DeclRefExpr>(E);
5532 if (!DRE || !isa<FunctionDecl>(DRE->getDecl()))
5533 return false;
5534
5535 return !S.checkAddressOfFunctionIsAvailable(
5536 cast<FunctionDecl>(DRE->getDecl()));
5537 }
5538
5539 /// Determine whether we can perform an elementwise array copy for this kind
5540 /// of entity.
canPerformArrayCopy(const InitializedEntity & Entity)5541 static bool canPerformArrayCopy(const InitializedEntity &Entity) {
5542 switch (Entity.getKind()) {
5543 case InitializedEntity::EK_LambdaCapture:
5544 // C++ [expr.prim.lambda]p24:
5545 // For array members, the array elements are direct-initialized in
5546 // increasing subscript order.
5547 return true;
5548
5549 case InitializedEntity::EK_Variable:
5550 // C++ [dcl.decomp]p1:
5551 // [...] each element is copy-initialized or direct-initialized from the
5552 // corresponding element of the assignment-expression [...]
5553 return isa<DecompositionDecl>(Entity.getDecl());
5554
5555 case InitializedEntity::EK_Member:
5556 // C++ [class.copy.ctor]p14:
5557 // - if the member is an array, each element is direct-initialized with
5558 // the corresponding subobject of x
5559 return Entity.isImplicitMemberInitializer();
5560
5561 case InitializedEntity::EK_ArrayElement:
5562 // All the above cases are intended to apply recursively, even though none
5563 // of them actually say that.
5564 if (auto *E = Entity.getParent())
5565 return canPerformArrayCopy(*E);
5566 break;
5567
5568 default:
5569 break;
5570 }
5571
5572 return false;
5573 }
5574
InitializeFrom(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Args,bool TopLevelOfInitList,bool TreatUnavailableAsInvalid)5575 void InitializationSequence::InitializeFrom(Sema &S,
5576 const InitializedEntity &Entity,
5577 const InitializationKind &Kind,
5578 MultiExprArg Args,
5579 bool TopLevelOfInitList,
5580 bool TreatUnavailableAsInvalid) {
5581 ASTContext &Context = S.Context;
5582
5583 // Eliminate non-overload placeholder types in the arguments. We
5584 // need to do this before checking whether types are dependent
5585 // because lowering a pseudo-object expression might well give us
5586 // something of dependent type.
5587 for (unsigned I = 0, E = Args.size(); I != E; ++I)
5588 if (Args[I]->getType()->isNonOverloadPlaceholderType()) {
5589 // FIXME: should we be doing this here?
5590 ExprResult result = S.CheckPlaceholderExpr(Args[I]);
5591 if (result.isInvalid()) {
5592 SetFailed(FK_PlaceholderType);
5593 return;
5594 }
5595 Args[I] = result.get();
5596 }
5597
5598 // C++0x [dcl.init]p16:
5599 // The semantics of initializers are as follows. The destination type is
5600 // the type of the object or reference being initialized and the source
5601 // type is the type of the initializer expression. The source type is not
5602 // defined when the initializer is a braced-init-list or when it is a
5603 // parenthesized list of expressions.
5604 QualType DestType = Entity.getType();
5605
5606 if (DestType->isDependentType() ||
5607 Expr::hasAnyTypeDependentArguments(Args)) {
5608 SequenceKind = DependentSequence;
5609 return;
5610 }
5611
5612 // Almost everything is a normal sequence.
5613 setSequenceKind(NormalSequence);
5614
5615 QualType SourceType;
5616 Expr *Initializer = nullptr;
5617 if (Args.size() == 1) {
5618 Initializer = Args[0];
5619 if (S.getLangOpts().ObjC) {
5620 if (S.CheckObjCBridgeRelatedConversions(Initializer->getBeginLoc(),
5621 DestType, Initializer->getType(),
5622 Initializer) ||
5623 S.ConversionToObjCStringLiteralCheck(DestType, Initializer))
5624 Args[0] = Initializer;
5625 }
5626 if (!isa<InitListExpr>(Initializer))
5627 SourceType = Initializer->getType();
5628 }
5629
5630 // - If the initializer is a (non-parenthesized) braced-init-list, the
5631 // object is list-initialized (8.5.4).
5632 if (Kind.getKind() != InitializationKind::IK_Direct) {
5633 if (InitListExpr *InitList = dyn_cast_or_null<InitListExpr>(Initializer)) {
5634 TryListInitialization(S, Entity, Kind, InitList, *this,
5635 TreatUnavailableAsInvalid);
5636 return;
5637 }
5638 }
5639
5640 // - If the destination type is a reference type, see 8.5.3.
5641 if (DestType->isReferenceType()) {
5642 // C++0x [dcl.init.ref]p1:
5643 // A variable declared to be a T& or T&&, that is, "reference to type T"
5644 // (8.3.2), shall be initialized by an object, or function, of type T or
5645 // by an object that can be converted into a T.
5646 // (Therefore, multiple arguments are not permitted.)
5647 if (Args.size() != 1)
5648 SetFailed(FK_TooManyInitsForReference);
5649 // C++17 [dcl.init.ref]p5:
5650 // A reference [...] is initialized by an expression [...] as follows:
5651 // If the initializer is not an expression, presumably we should reject,
5652 // but the standard fails to actually say so.
5653 else if (isa<InitListExpr>(Args[0]))
5654 SetFailed(FK_ParenthesizedListInitForReference);
5655 else
5656 TryReferenceInitialization(S, Entity, Kind, Args[0], *this);
5657 return;
5658 }
5659
5660 // - If the initializer is (), the object is value-initialized.
5661 if (Kind.getKind() == InitializationKind::IK_Value ||
5662 (Kind.getKind() == InitializationKind::IK_Direct && Args.empty())) {
5663 TryValueInitialization(S, Entity, Kind, *this);
5664 return;
5665 }
5666
5667 // Handle default initialization.
5668 if (Kind.getKind() == InitializationKind::IK_Default) {
5669 TryDefaultInitialization(S, Entity, Kind, *this);
5670 return;
5671 }
5672
5673 // - If the destination type is an array of characters, an array of
5674 // char16_t, an array of char32_t, or an array of wchar_t, and the
5675 // initializer is a string literal, see 8.5.2.
5676 // - Otherwise, if the destination type is an array, the program is
5677 // ill-formed.
5678 if (const ArrayType *DestAT = Context.getAsArrayType(DestType)) {
5679 if (Initializer && isa<VariableArrayType>(DestAT)) {
5680 SetFailed(FK_VariableLengthArrayHasInitializer);
5681 return;
5682 }
5683
5684 if (Initializer) {
5685 switch (IsStringInit(Initializer, DestAT, Context)) {
5686 case SIF_None:
5687 TryStringLiteralInitialization(S, Entity, Kind, Initializer, *this);
5688 return;
5689 case SIF_NarrowStringIntoWideChar:
5690 SetFailed(FK_NarrowStringIntoWideCharArray);
5691 return;
5692 case SIF_WideStringIntoChar:
5693 SetFailed(FK_WideStringIntoCharArray);
5694 return;
5695 case SIF_IncompatWideStringIntoWideChar:
5696 SetFailed(FK_IncompatWideStringIntoWideChar);
5697 return;
5698 case SIF_PlainStringIntoUTF8Char:
5699 SetFailed(FK_PlainStringIntoUTF8Char);
5700 return;
5701 case SIF_UTF8StringIntoPlainChar:
5702 SetFailed(FK_UTF8StringIntoPlainChar);
5703 return;
5704 case SIF_Other:
5705 break;
5706 }
5707 }
5708
5709 // Some kinds of initialization permit an array to be initialized from
5710 // another array of the same type, and perform elementwise initialization.
5711 if (Initializer && isa<ConstantArrayType>(DestAT) &&
5712 S.Context.hasSameUnqualifiedType(Initializer->getType(),
5713 Entity.getType()) &&
5714 canPerformArrayCopy(Entity)) {
5715 // If source is a prvalue, use it directly.
5716 if (Initializer->getValueKind() == VK_RValue) {
5717 AddArrayInitStep(DestType, /*IsGNUExtension*/false);
5718 return;
5719 }
5720
5721 // Emit element-at-a-time copy loop.
5722 InitializedEntity Element =
5723 InitializedEntity::InitializeElement(S.Context, 0, Entity);
5724 QualType InitEltT =
5725 Context.getAsArrayType(Initializer->getType())->getElementType();
5726 OpaqueValueExpr OVE(Initializer->getExprLoc(), InitEltT,
5727 Initializer->getValueKind(),
5728 Initializer->getObjectKind());
5729 Expr *OVEAsExpr = &OVE;
5730 InitializeFrom(S, Element, Kind, OVEAsExpr, TopLevelOfInitList,
5731 TreatUnavailableAsInvalid);
5732 if (!Failed())
5733 AddArrayInitLoopStep(Entity.getType(), InitEltT);
5734 return;
5735 }
5736
5737 // Note: as an GNU C extension, we allow initialization of an
5738 // array from a compound literal that creates an array of the same
5739 // type, so long as the initializer has no side effects.
5740 if (!S.getLangOpts().CPlusPlus && Initializer &&
5741 isa<CompoundLiteralExpr>(Initializer->IgnoreParens()) &&
5742 Initializer->getType()->isArrayType()) {
5743 const ArrayType *SourceAT
5744 = Context.getAsArrayType(Initializer->getType());
5745 if (!hasCompatibleArrayTypes(S.Context, DestAT, SourceAT))
5746 SetFailed(FK_ArrayTypeMismatch);
5747 else if (Initializer->HasSideEffects(S.Context))
5748 SetFailed(FK_NonConstantArrayInit);
5749 else {
5750 AddArrayInitStep(DestType, /*IsGNUExtension*/true);
5751 }
5752 }
5753 // Note: as a GNU C++ extension, we allow list-initialization of a
5754 // class member of array type from a parenthesized initializer list.
5755 else if (S.getLangOpts().CPlusPlus &&
5756 Entity.getKind() == InitializedEntity::EK_Member &&
5757 Initializer && isa<InitListExpr>(Initializer)) {
5758 TryListInitialization(S, Entity, Kind, cast<InitListExpr>(Initializer),
5759 *this, TreatUnavailableAsInvalid);
5760 AddParenthesizedArrayInitStep(DestType);
5761 } else if (DestAT->getElementType()->isCharType())
5762 SetFailed(FK_ArrayNeedsInitListOrStringLiteral);
5763 else if (IsWideCharCompatible(DestAT->getElementType(), Context))
5764 SetFailed(FK_ArrayNeedsInitListOrWideStringLiteral);
5765 else
5766 SetFailed(FK_ArrayNeedsInitList);
5767
5768 return;
5769 }
5770
5771 // Determine whether we should consider writeback conversions for
5772 // Objective-C ARC.
5773 bool allowObjCWritebackConversion = S.getLangOpts().ObjCAutoRefCount &&
5774 Entity.isParameterKind();
5775
5776 if (TryOCLSamplerInitialization(S, *this, DestType, Initializer))
5777 return;
5778
5779 // We're at the end of the line for C: it's either a write-back conversion
5780 // or it's a C assignment. There's no need to check anything else.
5781 if (!S.getLangOpts().CPlusPlus) {
5782 // If allowed, check whether this is an Objective-C writeback conversion.
5783 if (allowObjCWritebackConversion &&
5784 tryObjCWritebackConversion(S, *this, Entity, Initializer)) {
5785 return;
5786 }
5787
5788 if (TryOCLZeroOpaqueTypeInitialization(S, *this, DestType, Initializer))
5789 return;
5790
5791 // Handle initialization in C
5792 AddCAssignmentStep(DestType);
5793 MaybeProduceObjCObject(S, *this, Entity);
5794 return;
5795 }
5796
5797 assert(S.getLangOpts().CPlusPlus);
5798
5799 // - If the destination type is a (possibly cv-qualified) class type:
5800 if (DestType->isRecordType()) {
5801 // - If the initialization is direct-initialization, or if it is
5802 // copy-initialization where the cv-unqualified version of the
5803 // source type is the same class as, or a derived class of, the
5804 // class of the destination, constructors are considered. [...]
5805 if (Kind.getKind() == InitializationKind::IK_Direct ||
5806 (Kind.getKind() == InitializationKind::IK_Copy &&
5807 (Context.hasSameUnqualifiedType(SourceType, DestType) ||
5808 S.IsDerivedFrom(Initializer->getBeginLoc(), SourceType, DestType))))
5809 TryConstructorInitialization(S, Entity, Kind, Args,
5810 DestType, DestType, *this);
5811 // - Otherwise (i.e., for the remaining copy-initialization cases),
5812 // user-defined conversion sequences that can convert from the source
5813 // type to the destination type or (when a conversion function is
5814 // used) to a derived class thereof are enumerated as described in
5815 // 13.3.1.4, and the best one is chosen through overload resolution
5816 // (13.3).
5817 else
5818 TryUserDefinedConversion(S, DestType, Kind, Initializer, *this,
5819 TopLevelOfInitList);
5820 return;
5821 }
5822
5823 assert(Args.size() >= 1 && "Zero-argument case handled above");
5824
5825 // The remaining cases all need a source type.
5826 if (Args.size() > 1) {
5827 SetFailed(FK_TooManyInitsForScalar);
5828 return;
5829 } else if (isa<InitListExpr>(Args[0])) {
5830 SetFailed(FK_ParenthesizedListInitForScalar);
5831 return;
5832 }
5833
5834 // - Otherwise, if the source type is a (possibly cv-qualified) class
5835 // type, conversion functions are considered.
5836 if (!SourceType.isNull() && SourceType->isRecordType()) {
5837 // For a conversion to _Atomic(T) from either T or a class type derived
5838 // from T, initialize the T object then convert to _Atomic type.
5839 bool NeedAtomicConversion = false;
5840 if (const AtomicType *Atomic = DestType->getAs<AtomicType>()) {
5841 if (Context.hasSameUnqualifiedType(SourceType, Atomic->getValueType()) ||
5842 S.IsDerivedFrom(Initializer->getBeginLoc(), SourceType,
5843 Atomic->getValueType())) {
5844 DestType = Atomic->getValueType();
5845 NeedAtomicConversion = true;
5846 }
5847 }
5848
5849 TryUserDefinedConversion(S, DestType, Kind, Initializer, *this,
5850 TopLevelOfInitList);
5851 MaybeProduceObjCObject(S, *this, Entity);
5852 if (!Failed() && NeedAtomicConversion)
5853 AddAtomicConversionStep(Entity.getType());
5854 return;
5855 }
5856
5857 // - Otherwise, the initial value of the object being initialized is the
5858 // (possibly converted) value of the initializer expression. Standard
5859 // conversions (Clause 4) will be used, if necessary, to convert the
5860 // initializer expression to the cv-unqualified version of the
5861 // destination type; no user-defined conversions are considered.
5862
5863 ImplicitConversionSequence ICS
5864 = S.TryImplicitConversion(Initializer, DestType,
5865 /*SuppressUserConversions*/true,
5866 /*AllowExplicitConversions*/ false,
5867 /*InOverloadResolution*/ false,
5868 /*CStyle=*/Kind.isCStyleOrFunctionalCast(),
5869 allowObjCWritebackConversion);
5870
5871 if (ICS.isStandard() &&
5872 ICS.Standard.Second == ICK_Writeback_Conversion) {
5873 // Objective-C ARC writeback conversion.
5874
5875 // We should copy unless we're passing to an argument explicitly
5876 // marked 'out'.
5877 bool ShouldCopy = true;
5878 if (ParmVarDecl *Param = cast_or_null<ParmVarDecl>(Entity.getDecl()))
5879 ShouldCopy = (Param->getObjCDeclQualifier() != ParmVarDecl::OBJC_TQ_Out);
5880
5881 // If there was an lvalue adjustment, add it as a separate conversion.
5882 if (ICS.Standard.First == ICK_Array_To_Pointer ||
5883 ICS.Standard.First == ICK_Lvalue_To_Rvalue) {
5884 ImplicitConversionSequence LvalueICS;
5885 LvalueICS.setStandard();
5886 LvalueICS.Standard.setAsIdentityConversion();
5887 LvalueICS.Standard.setAllToTypes(ICS.Standard.getToType(0));
5888 LvalueICS.Standard.First = ICS.Standard.First;
5889 AddConversionSequenceStep(LvalueICS, ICS.Standard.getToType(0));
5890 }
5891
5892 AddPassByIndirectCopyRestoreStep(DestType, ShouldCopy);
5893 } else if (ICS.isBad()) {
5894 DeclAccessPair dap;
5895 if (isLibstdcxxPointerReturnFalseHack(S, Entity, Initializer)) {
5896 AddZeroInitializationStep(Entity.getType());
5897 } else if (Initializer->getType() == Context.OverloadTy &&
5898 !S.ResolveAddressOfOverloadedFunction(Initializer, DestType,
5899 false, dap))
5900 SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
5901 else if (Initializer->getType()->isFunctionType() &&
5902 isExprAnUnaddressableFunction(S, Initializer))
5903 SetFailed(InitializationSequence::FK_AddressOfUnaddressableFunction);
5904 else
5905 SetFailed(InitializationSequence::FK_ConversionFailed);
5906 } else {
5907 AddConversionSequenceStep(ICS, DestType, TopLevelOfInitList);
5908
5909 MaybeProduceObjCObject(S, *this, Entity);
5910 }
5911 }
5912
~InitializationSequence()5913 InitializationSequence::~InitializationSequence() {
5914 for (auto &S : Steps)
5915 S.Destroy();
5916 }
5917
5918 //===----------------------------------------------------------------------===//
5919 // Perform initialization
5920 //===----------------------------------------------------------------------===//
5921 static Sema::AssignmentAction
getAssignmentAction(const InitializedEntity & Entity,bool Diagnose=false)5922 getAssignmentAction(const InitializedEntity &Entity, bool Diagnose = false) {
5923 switch(Entity.getKind()) {
5924 case InitializedEntity::EK_Variable:
5925 case InitializedEntity::EK_New:
5926 case InitializedEntity::EK_Exception:
5927 case InitializedEntity::EK_Base:
5928 case InitializedEntity::EK_Delegating:
5929 return Sema::AA_Initializing;
5930
5931 case InitializedEntity::EK_Parameter:
5932 if (Entity.getDecl() &&
5933 isa<ObjCMethodDecl>(Entity.getDecl()->getDeclContext()))
5934 return Sema::AA_Sending;
5935
5936 return Sema::AA_Passing;
5937
5938 case InitializedEntity::EK_Parameter_CF_Audited:
5939 if (Entity.getDecl() &&
5940 isa<ObjCMethodDecl>(Entity.getDecl()->getDeclContext()))
5941 return Sema::AA_Sending;
5942
5943 return !Diagnose ? Sema::AA_Passing : Sema::AA_Passing_CFAudited;
5944
5945 case InitializedEntity::EK_Result:
5946 case InitializedEntity::EK_StmtExprResult: // FIXME: Not quite right.
5947 return Sema::AA_Returning;
5948
5949 case InitializedEntity::EK_Temporary:
5950 case InitializedEntity::EK_RelatedResult:
5951 // FIXME: Can we tell apart casting vs. converting?
5952 return Sema::AA_Casting;
5953
5954 case InitializedEntity::EK_Member:
5955 case InitializedEntity::EK_Binding:
5956 case InitializedEntity::EK_ArrayElement:
5957 case InitializedEntity::EK_VectorElement:
5958 case InitializedEntity::EK_ComplexElement:
5959 case InitializedEntity::EK_BlockElement:
5960 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
5961 case InitializedEntity::EK_LambdaCapture:
5962 case InitializedEntity::EK_CompoundLiteralInit:
5963 return Sema::AA_Initializing;
5964 }
5965
5966 llvm_unreachable("Invalid EntityKind!");
5967 }
5968
5969 /// Whether we should bind a created object as a temporary when
5970 /// initializing the given entity.
shouldBindAsTemporary(const InitializedEntity & Entity)5971 static bool shouldBindAsTemporary(const InitializedEntity &Entity) {
5972 switch (Entity.getKind()) {
5973 case InitializedEntity::EK_ArrayElement:
5974 case InitializedEntity::EK_Member:
5975 case InitializedEntity::EK_Result:
5976 case InitializedEntity::EK_StmtExprResult:
5977 case InitializedEntity::EK_New:
5978 case InitializedEntity::EK_Variable:
5979 case InitializedEntity::EK_Base:
5980 case InitializedEntity::EK_Delegating:
5981 case InitializedEntity::EK_VectorElement:
5982 case InitializedEntity::EK_ComplexElement:
5983 case InitializedEntity::EK_Exception:
5984 case InitializedEntity::EK_BlockElement:
5985 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
5986 case InitializedEntity::EK_LambdaCapture:
5987 case InitializedEntity::EK_CompoundLiteralInit:
5988 return false;
5989
5990 case InitializedEntity::EK_Parameter:
5991 case InitializedEntity::EK_Parameter_CF_Audited:
5992 case InitializedEntity::EK_Temporary:
5993 case InitializedEntity::EK_RelatedResult:
5994 case InitializedEntity::EK_Binding:
5995 return true;
5996 }
5997
5998 llvm_unreachable("missed an InitializedEntity kind?");
5999 }
6000
6001 /// Whether the given entity, when initialized with an object
6002 /// created for that initialization, requires destruction.
shouldDestroyEntity(const InitializedEntity & Entity)6003 static bool shouldDestroyEntity(const InitializedEntity &Entity) {
6004 switch (Entity.getKind()) {
6005 case InitializedEntity::EK_Result:
6006 case InitializedEntity::EK_StmtExprResult:
6007 case InitializedEntity::EK_New:
6008 case InitializedEntity::EK_Base:
6009 case InitializedEntity::EK_Delegating:
6010 case InitializedEntity::EK_VectorElement:
6011 case InitializedEntity::EK_ComplexElement:
6012 case InitializedEntity::EK_BlockElement:
6013 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6014 case InitializedEntity::EK_LambdaCapture:
6015 return false;
6016
6017 case InitializedEntity::EK_Member:
6018 case InitializedEntity::EK_Binding:
6019 case InitializedEntity::EK_Variable:
6020 case InitializedEntity::EK_Parameter:
6021 case InitializedEntity::EK_Parameter_CF_Audited:
6022 case InitializedEntity::EK_Temporary:
6023 case InitializedEntity::EK_ArrayElement:
6024 case InitializedEntity::EK_Exception:
6025 case InitializedEntity::EK_CompoundLiteralInit:
6026 case InitializedEntity::EK_RelatedResult:
6027 return true;
6028 }
6029
6030 llvm_unreachable("missed an InitializedEntity kind?");
6031 }
6032
6033 /// Get the location at which initialization diagnostics should appear.
getInitializationLoc(const InitializedEntity & Entity,Expr * Initializer)6034 static SourceLocation getInitializationLoc(const InitializedEntity &Entity,
6035 Expr *Initializer) {
6036 switch (Entity.getKind()) {
6037 case InitializedEntity::EK_Result:
6038 case InitializedEntity::EK_StmtExprResult:
6039 return Entity.getReturnLoc();
6040
6041 case InitializedEntity::EK_Exception:
6042 return Entity.getThrowLoc();
6043
6044 case InitializedEntity::EK_Variable:
6045 case InitializedEntity::EK_Binding:
6046 return Entity.getDecl()->getLocation();
6047
6048 case InitializedEntity::EK_LambdaCapture:
6049 return Entity.getCaptureLoc();
6050
6051 case InitializedEntity::EK_ArrayElement:
6052 case InitializedEntity::EK_Member:
6053 case InitializedEntity::EK_Parameter:
6054 case InitializedEntity::EK_Parameter_CF_Audited:
6055 case InitializedEntity::EK_Temporary:
6056 case InitializedEntity::EK_New:
6057 case InitializedEntity::EK_Base:
6058 case InitializedEntity::EK_Delegating:
6059 case InitializedEntity::EK_VectorElement:
6060 case InitializedEntity::EK_ComplexElement:
6061 case InitializedEntity::EK_BlockElement:
6062 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6063 case InitializedEntity::EK_CompoundLiteralInit:
6064 case InitializedEntity::EK_RelatedResult:
6065 return Initializer->getBeginLoc();
6066 }
6067 llvm_unreachable("missed an InitializedEntity kind?");
6068 }
6069
6070 /// Make a (potentially elidable) temporary copy of the object
6071 /// provided by the given initializer by calling the appropriate copy
6072 /// constructor.
6073 ///
6074 /// \param S The Sema object used for type-checking.
6075 ///
6076 /// \param T The type of the temporary object, which must either be
6077 /// the type of the initializer expression or a superclass thereof.
6078 ///
6079 /// \param Entity The entity being initialized.
6080 ///
6081 /// \param CurInit The initializer expression.
6082 ///
6083 /// \param IsExtraneousCopy Whether this is an "extraneous" copy that
6084 /// is permitted in C++03 (but not C++0x) when binding a reference to
6085 /// an rvalue.
6086 ///
6087 /// \returns An expression that copies the initializer expression into
6088 /// a temporary object, or an error expression if a copy could not be
6089 /// created.
CopyObject(Sema & S,QualType T,const InitializedEntity & Entity,ExprResult CurInit,bool IsExtraneousCopy)6090 static ExprResult CopyObject(Sema &S,
6091 QualType T,
6092 const InitializedEntity &Entity,
6093 ExprResult CurInit,
6094 bool IsExtraneousCopy) {
6095 if (CurInit.isInvalid())
6096 return CurInit;
6097 // Determine which class type we're copying to.
6098 Expr *CurInitExpr = (Expr *)CurInit.get();
6099 CXXRecordDecl *Class = nullptr;
6100 if (const RecordType *Record = T->getAs<RecordType>())
6101 Class = cast<CXXRecordDecl>(Record->getDecl());
6102 if (!Class)
6103 return CurInit;
6104
6105 SourceLocation Loc = getInitializationLoc(Entity, CurInit.get());
6106
6107 // Make sure that the type we are copying is complete.
6108 if (S.RequireCompleteType(Loc, T, diag::err_temp_copy_incomplete))
6109 return CurInit;
6110
6111 // Perform overload resolution using the class's constructors. Per
6112 // C++11 [dcl.init]p16, second bullet for class types, this initialization
6113 // is direct-initialization.
6114 OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
6115 DeclContext::lookup_result Ctors = S.LookupConstructors(Class);
6116
6117 OverloadCandidateSet::iterator Best;
6118 switch (ResolveConstructorOverload(
6119 S, Loc, CurInitExpr, CandidateSet, T, Ctors, Best,
6120 /*CopyInitializing=*/false, /*AllowExplicit=*/true,
6121 /*OnlyListConstructors=*/false, /*IsListInit=*/false,
6122 /*SecondStepOfCopyInit=*/true)) {
6123 case OR_Success:
6124 break;
6125
6126 case OR_No_Viable_Function:
6127 CandidateSet.NoteCandidates(
6128 PartialDiagnosticAt(
6129 Loc, S.PDiag(IsExtraneousCopy && !S.isSFINAEContext()
6130 ? diag::ext_rvalue_to_reference_temp_copy_no_viable
6131 : diag::err_temp_copy_no_viable)
6132 << (int)Entity.getKind() << CurInitExpr->getType()
6133 << CurInitExpr->getSourceRange()),
6134 S, OCD_AllCandidates, CurInitExpr);
6135 if (!IsExtraneousCopy || S.isSFINAEContext())
6136 return ExprError();
6137 return CurInit;
6138
6139 case OR_Ambiguous:
6140 CandidateSet.NoteCandidates(
6141 PartialDiagnosticAt(Loc, S.PDiag(diag::err_temp_copy_ambiguous)
6142 << (int)Entity.getKind()
6143 << CurInitExpr->getType()
6144 << CurInitExpr->getSourceRange()),
6145 S, OCD_AmbiguousCandidates, CurInitExpr);
6146 return ExprError();
6147
6148 case OR_Deleted:
6149 S.Diag(Loc, diag::err_temp_copy_deleted)
6150 << (int)Entity.getKind() << CurInitExpr->getType()
6151 << CurInitExpr->getSourceRange();
6152 S.NoteDeletedFunction(Best->Function);
6153 return ExprError();
6154 }
6155
6156 bool HadMultipleCandidates = CandidateSet.size() > 1;
6157
6158 CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Best->Function);
6159 SmallVector<Expr*, 8> ConstructorArgs;
6160 CurInit.get(); // Ownership transferred into MultiExprArg, below.
6161
6162 S.CheckConstructorAccess(Loc, Constructor, Best->FoundDecl, Entity,
6163 IsExtraneousCopy);
6164
6165 if (IsExtraneousCopy) {
6166 // If this is a totally extraneous copy for C++03 reference
6167 // binding purposes, just return the original initialization
6168 // expression. We don't generate an (elided) copy operation here
6169 // because doing so would require us to pass down a flag to avoid
6170 // infinite recursion, where each step adds another extraneous,
6171 // elidable copy.
6172
6173 // Instantiate the default arguments of any extra parameters in
6174 // the selected copy constructor, as if we were going to create a
6175 // proper call to the copy constructor.
6176 for (unsigned I = 1, N = Constructor->getNumParams(); I != N; ++I) {
6177 ParmVarDecl *Parm = Constructor->getParamDecl(I);
6178 if (S.RequireCompleteType(Loc, Parm->getType(),
6179 diag::err_call_incomplete_argument))
6180 break;
6181
6182 // Build the default argument expression; we don't actually care
6183 // if this succeeds or not, because this routine will complain
6184 // if there was a problem.
6185 S.BuildCXXDefaultArgExpr(Loc, Constructor, Parm);
6186 }
6187
6188 return CurInitExpr;
6189 }
6190
6191 // Determine the arguments required to actually perform the
6192 // constructor call (we might have derived-to-base conversions, or
6193 // the copy constructor may have default arguments).
6194 if (S.CompleteConstructorCall(Constructor, CurInitExpr, Loc, ConstructorArgs))
6195 return ExprError();
6196
6197 // C++0x [class.copy]p32:
6198 // When certain criteria are met, an implementation is allowed to
6199 // omit the copy/move construction of a class object, even if the
6200 // copy/move constructor and/or destructor for the object have
6201 // side effects. [...]
6202 // - when a temporary class object that has not been bound to a
6203 // reference (12.2) would be copied/moved to a class object
6204 // with the same cv-unqualified type, the copy/move operation
6205 // can be omitted by constructing the temporary object
6206 // directly into the target of the omitted copy/move
6207 //
6208 // Note that the other three bullets are handled elsewhere. Copy
6209 // elision for return statements and throw expressions are handled as part
6210 // of constructor initialization, while copy elision for exception handlers
6211 // is handled by the run-time.
6212 //
6213 // FIXME: If the function parameter is not the same type as the temporary, we
6214 // should still be able to elide the copy, but we don't have a way to
6215 // represent in the AST how much should be elided in this case.
6216 bool Elidable =
6217 CurInitExpr->isTemporaryObject(S.Context, Class) &&
6218 S.Context.hasSameUnqualifiedType(
6219 Best->Function->getParamDecl(0)->getType().getNonReferenceType(),
6220 CurInitExpr->getType());
6221
6222 // Actually perform the constructor call.
6223 CurInit = S.BuildCXXConstructExpr(Loc, T, Best->FoundDecl, Constructor,
6224 Elidable,
6225 ConstructorArgs,
6226 HadMultipleCandidates,
6227 /*ListInit*/ false,
6228 /*StdInitListInit*/ false,
6229 /*ZeroInit*/ false,
6230 CXXConstructExpr::CK_Complete,
6231 SourceRange());
6232
6233 // If we're supposed to bind temporaries, do so.
6234 if (!CurInit.isInvalid() && shouldBindAsTemporary(Entity))
6235 CurInit = S.MaybeBindToTemporary(CurInit.getAs<Expr>());
6236 return CurInit;
6237 }
6238
6239 /// Check whether elidable copy construction for binding a reference to
6240 /// a temporary would have succeeded if we were building in C++98 mode, for
6241 /// -Wc++98-compat.
CheckCXX98CompatAccessibleCopy(Sema & S,const InitializedEntity & Entity,Expr * CurInitExpr)6242 static void CheckCXX98CompatAccessibleCopy(Sema &S,
6243 const InitializedEntity &Entity,
6244 Expr *CurInitExpr) {
6245 assert(S.getLangOpts().CPlusPlus11);
6246
6247 const RecordType *Record = CurInitExpr->getType()->getAs<RecordType>();
6248 if (!Record)
6249 return;
6250
6251 SourceLocation Loc = getInitializationLoc(Entity, CurInitExpr);
6252 if (S.Diags.isIgnored(diag::warn_cxx98_compat_temp_copy, Loc))
6253 return;
6254
6255 // Find constructors which would have been considered.
6256 OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
6257 DeclContext::lookup_result Ctors =
6258 S.LookupConstructors(cast<CXXRecordDecl>(Record->getDecl()));
6259
6260 // Perform overload resolution.
6261 OverloadCandidateSet::iterator Best;
6262 OverloadingResult OR = ResolveConstructorOverload(
6263 S, Loc, CurInitExpr, CandidateSet, CurInitExpr->getType(), Ctors, Best,
6264 /*CopyInitializing=*/false, /*AllowExplicit=*/true,
6265 /*OnlyListConstructors=*/false, /*IsListInit=*/false,
6266 /*SecondStepOfCopyInit=*/true);
6267
6268 PartialDiagnostic Diag = S.PDiag(diag::warn_cxx98_compat_temp_copy)
6269 << OR << (int)Entity.getKind() << CurInitExpr->getType()
6270 << CurInitExpr->getSourceRange();
6271
6272 switch (OR) {
6273 case OR_Success:
6274 S.CheckConstructorAccess(Loc, cast<CXXConstructorDecl>(Best->Function),
6275 Best->FoundDecl, Entity, Diag);
6276 // FIXME: Check default arguments as far as that's possible.
6277 break;
6278
6279 case OR_No_Viable_Function:
6280 CandidateSet.NoteCandidates(PartialDiagnosticAt(Loc, Diag), S,
6281 OCD_AllCandidates, CurInitExpr);
6282 break;
6283
6284 case OR_Ambiguous:
6285 CandidateSet.NoteCandidates(PartialDiagnosticAt(Loc, Diag), S,
6286 OCD_AmbiguousCandidates, CurInitExpr);
6287 break;
6288
6289 case OR_Deleted:
6290 S.Diag(Loc, Diag);
6291 S.NoteDeletedFunction(Best->Function);
6292 break;
6293 }
6294 }
6295
PrintInitLocationNote(Sema & S,const InitializedEntity & Entity)6296 void InitializationSequence::PrintInitLocationNote(Sema &S,
6297 const InitializedEntity &Entity) {
6298 if (Entity.isParameterKind() && Entity.getDecl()) {
6299 if (Entity.getDecl()->getLocation().isInvalid())
6300 return;
6301
6302 if (Entity.getDecl()->getDeclName())
6303 S.Diag(Entity.getDecl()->getLocation(), diag::note_parameter_named_here)
6304 << Entity.getDecl()->getDeclName();
6305 else
6306 S.Diag(Entity.getDecl()->getLocation(), diag::note_parameter_here);
6307 }
6308 else if (Entity.getKind() == InitializedEntity::EK_RelatedResult &&
6309 Entity.getMethodDecl())
6310 S.Diag(Entity.getMethodDecl()->getLocation(),
6311 diag::note_method_return_type_change)
6312 << Entity.getMethodDecl()->getDeclName();
6313 }
6314
6315 /// Returns true if the parameters describe a constructor initialization of
6316 /// an explicit temporary object, e.g. "Point(x, y)".
isExplicitTemporary(const InitializedEntity & Entity,const InitializationKind & Kind,unsigned NumArgs)6317 static bool isExplicitTemporary(const InitializedEntity &Entity,
6318 const InitializationKind &Kind,
6319 unsigned NumArgs) {
6320 switch (Entity.getKind()) {
6321 case InitializedEntity::EK_Temporary:
6322 case InitializedEntity::EK_CompoundLiteralInit:
6323 case InitializedEntity::EK_RelatedResult:
6324 break;
6325 default:
6326 return false;
6327 }
6328
6329 switch (Kind.getKind()) {
6330 case InitializationKind::IK_DirectList:
6331 return true;
6332 // FIXME: Hack to work around cast weirdness.
6333 case InitializationKind::IK_Direct:
6334 case InitializationKind::IK_Value:
6335 return NumArgs != 1;
6336 default:
6337 return false;
6338 }
6339 }
6340
6341 static ExprResult
PerformConstructorInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Args,const InitializationSequence::Step & Step,bool & ConstructorInitRequiresZeroInit,bool IsListInitialization,bool IsStdInitListInitialization,SourceLocation LBraceLoc,SourceLocation RBraceLoc)6342 PerformConstructorInitialization(Sema &S,
6343 const InitializedEntity &Entity,
6344 const InitializationKind &Kind,
6345 MultiExprArg Args,
6346 const InitializationSequence::Step& Step,
6347 bool &ConstructorInitRequiresZeroInit,
6348 bool IsListInitialization,
6349 bool IsStdInitListInitialization,
6350 SourceLocation LBraceLoc,
6351 SourceLocation RBraceLoc) {
6352 unsigned NumArgs = Args.size();
6353 CXXConstructorDecl *Constructor
6354 = cast<CXXConstructorDecl>(Step.Function.Function);
6355 bool HadMultipleCandidates = Step.Function.HadMultipleCandidates;
6356
6357 // Build a call to the selected constructor.
6358 SmallVector<Expr*, 8> ConstructorArgs;
6359 SourceLocation Loc = (Kind.isCopyInit() && Kind.getEqualLoc().isValid())
6360 ? Kind.getEqualLoc()
6361 : Kind.getLocation();
6362
6363 if (Kind.getKind() == InitializationKind::IK_Default) {
6364 // Force even a trivial, implicit default constructor to be
6365 // semantically checked. We do this explicitly because we don't build
6366 // the definition for completely trivial constructors.
6367 assert(Constructor->getParent() && "No parent class for constructor.");
6368 if (Constructor->isDefaulted() && Constructor->isDefaultConstructor() &&
6369 Constructor->isTrivial() && !Constructor->isUsed(false)) {
6370 S.runWithSufficientStackSpace(Loc, [&] {
6371 S.DefineImplicitDefaultConstructor(Loc, Constructor);
6372 });
6373 }
6374 }
6375
6376 ExprResult CurInit((Expr *)nullptr);
6377
6378 // C++ [over.match.copy]p1:
6379 // - When initializing a temporary to be bound to the first parameter
6380 // of a constructor that takes a reference to possibly cv-qualified
6381 // T as its first argument, called with a single argument in the
6382 // context of direct-initialization, explicit conversion functions
6383 // are also considered.
6384 bool AllowExplicitConv =
6385 Kind.AllowExplicit() && !Kind.isCopyInit() && Args.size() == 1 &&
6386 hasCopyOrMoveCtorParam(S.Context,
6387 getConstructorInfo(Step.Function.FoundDecl));
6388
6389 // Determine the arguments required to actually perform the constructor
6390 // call.
6391 if (S.CompleteConstructorCall(Constructor, Args,
6392 Loc, ConstructorArgs,
6393 AllowExplicitConv,
6394 IsListInitialization))
6395 return ExprError();
6396
6397
6398 if (isExplicitTemporary(Entity, Kind, NumArgs)) {
6399 // An explicitly-constructed temporary, e.g., X(1, 2).
6400 if (S.DiagnoseUseOfDecl(Constructor, Loc))
6401 return ExprError();
6402
6403 TypeSourceInfo *TSInfo = Entity.getTypeSourceInfo();
6404 if (!TSInfo)
6405 TSInfo = S.Context.getTrivialTypeSourceInfo(Entity.getType(), Loc);
6406 SourceRange ParenOrBraceRange =
6407 (Kind.getKind() == InitializationKind::IK_DirectList)
6408 ? SourceRange(LBraceLoc, RBraceLoc)
6409 : Kind.getParenOrBraceRange();
6410
6411 if (auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(
6412 Step.Function.FoundDecl.getDecl())) {
6413 Constructor = S.findInheritingConstructor(Loc, Constructor, Shadow);
6414 if (S.DiagnoseUseOfDecl(Constructor, Loc))
6415 return ExprError();
6416 }
6417 S.MarkFunctionReferenced(Loc, Constructor);
6418
6419 CurInit = CXXTemporaryObjectExpr::Create(
6420 S.Context, Constructor,
6421 Entity.getType().getNonLValueExprType(S.Context), TSInfo,
6422 ConstructorArgs, ParenOrBraceRange, HadMultipleCandidates,
6423 IsListInitialization, IsStdInitListInitialization,
6424 ConstructorInitRequiresZeroInit);
6425 } else {
6426 CXXConstructExpr::ConstructionKind ConstructKind =
6427 CXXConstructExpr::CK_Complete;
6428
6429 if (Entity.getKind() == InitializedEntity::EK_Base) {
6430 ConstructKind = Entity.getBaseSpecifier()->isVirtual() ?
6431 CXXConstructExpr::CK_VirtualBase :
6432 CXXConstructExpr::CK_NonVirtualBase;
6433 } else if (Entity.getKind() == InitializedEntity::EK_Delegating) {
6434 ConstructKind = CXXConstructExpr::CK_Delegating;
6435 }
6436
6437 // Only get the parenthesis or brace range if it is a list initialization or
6438 // direct construction.
6439 SourceRange ParenOrBraceRange;
6440 if (IsListInitialization)
6441 ParenOrBraceRange = SourceRange(LBraceLoc, RBraceLoc);
6442 else if (Kind.getKind() == InitializationKind::IK_Direct)
6443 ParenOrBraceRange = Kind.getParenOrBraceRange();
6444
6445 // If the entity allows NRVO, mark the construction as elidable
6446 // unconditionally.
6447 if (Entity.allowsNRVO())
6448 CurInit = S.BuildCXXConstructExpr(Loc, Step.Type,
6449 Step.Function.FoundDecl,
6450 Constructor, /*Elidable=*/true,
6451 ConstructorArgs,
6452 HadMultipleCandidates,
6453 IsListInitialization,
6454 IsStdInitListInitialization,
6455 ConstructorInitRequiresZeroInit,
6456 ConstructKind,
6457 ParenOrBraceRange);
6458 else
6459 CurInit = S.BuildCXXConstructExpr(Loc, Step.Type,
6460 Step.Function.FoundDecl,
6461 Constructor,
6462 ConstructorArgs,
6463 HadMultipleCandidates,
6464 IsListInitialization,
6465 IsStdInitListInitialization,
6466 ConstructorInitRequiresZeroInit,
6467 ConstructKind,
6468 ParenOrBraceRange);
6469 }
6470 if (CurInit.isInvalid())
6471 return ExprError();
6472
6473 // Only check access if all of that succeeded.
6474 S.CheckConstructorAccess(Loc, Constructor, Step.Function.FoundDecl, Entity);
6475 if (S.DiagnoseUseOfDecl(Step.Function.FoundDecl, Loc))
6476 return ExprError();
6477
6478 if (const ArrayType *AT = S.Context.getAsArrayType(Entity.getType()))
6479 if (checkDestructorReference(S.Context.getBaseElementType(AT), Loc, S))
6480 return ExprError();
6481
6482 if (shouldBindAsTemporary(Entity))
6483 CurInit = S.MaybeBindToTemporary(CurInit.get());
6484
6485 return CurInit;
6486 }
6487
6488 namespace {
6489 enum LifetimeKind {
6490 /// The lifetime of a temporary bound to this entity ends at the end of the
6491 /// full-expression, and that's (probably) fine.
6492 LK_FullExpression,
6493
6494 /// The lifetime of a temporary bound to this entity is extended to the
6495 /// lifeitme of the entity itself.
6496 LK_Extended,
6497
6498 /// The lifetime of a temporary bound to this entity probably ends too soon,
6499 /// because the entity is allocated in a new-expression.
6500 LK_New,
6501
6502 /// The lifetime of a temporary bound to this entity ends too soon, because
6503 /// the entity is a return object.
6504 LK_Return,
6505
6506 /// The lifetime of a temporary bound to this entity ends too soon, because
6507 /// the entity is the result of a statement expression.
6508 LK_StmtExprResult,
6509
6510 /// This is a mem-initializer: if it would extend a temporary (other than via
6511 /// a default member initializer), the program is ill-formed.
6512 LK_MemInitializer,
6513 };
6514 using LifetimeResult =
6515 llvm::PointerIntPair<const InitializedEntity *, 3, LifetimeKind>;
6516 }
6517
6518 /// Determine the declaration which an initialized entity ultimately refers to,
6519 /// for the purpose of lifetime-extending a temporary bound to a reference in
6520 /// the initialization of \p Entity.
getEntityLifetime(const InitializedEntity * Entity,const InitializedEntity * InitField=nullptr)6521 static LifetimeResult getEntityLifetime(
6522 const InitializedEntity *Entity,
6523 const InitializedEntity *InitField = nullptr) {
6524 // C++11 [class.temporary]p5:
6525 switch (Entity->getKind()) {
6526 case InitializedEntity::EK_Variable:
6527 // The temporary [...] persists for the lifetime of the reference
6528 return {Entity, LK_Extended};
6529
6530 case InitializedEntity::EK_Member:
6531 // For subobjects, we look at the complete object.
6532 if (Entity->getParent())
6533 return getEntityLifetime(Entity->getParent(), Entity);
6534
6535 // except:
6536 // C++17 [class.base.init]p8:
6537 // A temporary expression bound to a reference member in a
6538 // mem-initializer is ill-formed.
6539 // C++17 [class.base.init]p11:
6540 // A temporary expression bound to a reference member from a
6541 // default member initializer is ill-formed.
6542 //
6543 // The context of p11 and its example suggest that it's only the use of a
6544 // default member initializer from a constructor that makes the program
6545 // ill-formed, not its mere existence, and that it can even be used by
6546 // aggregate initialization.
6547 return {Entity, Entity->isDefaultMemberInitializer() ? LK_Extended
6548 : LK_MemInitializer};
6549
6550 case InitializedEntity::EK_Binding:
6551 // Per [dcl.decomp]p3, the binding is treated as a variable of reference
6552 // type.
6553 return {Entity, LK_Extended};
6554
6555 case InitializedEntity::EK_Parameter:
6556 case InitializedEntity::EK_Parameter_CF_Audited:
6557 // -- A temporary bound to a reference parameter in a function call
6558 // persists until the completion of the full-expression containing
6559 // the call.
6560 return {nullptr, LK_FullExpression};
6561
6562 case InitializedEntity::EK_Result:
6563 // -- The lifetime of a temporary bound to the returned value in a
6564 // function return statement is not extended; the temporary is
6565 // destroyed at the end of the full-expression in the return statement.
6566 return {nullptr, LK_Return};
6567
6568 case InitializedEntity::EK_StmtExprResult:
6569 // FIXME: Should we lifetime-extend through the result of a statement
6570 // expression?
6571 return {nullptr, LK_StmtExprResult};
6572
6573 case InitializedEntity::EK_New:
6574 // -- A temporary bound to a reference in a new-initializer persists
6575 // until the completion of the full-expression containing the
6576 // new-initializer.
6577 return {nullptr, LK_New};
6578
6579 case InitializedEntity::EK_Temporary:
6580 case InitializedEntity::EK_CompoundLiteralInit:
6581 case InitializedEntity::EK_RelatedResult:
6582 // We don't yet know the storage duration of the surrounding temporary.
6583 // Assume it's got full-expression duration for now, it will patch up our
6584 // storage duration if that's not correct.
6585 return {nullptr, LK_FullExpression};
6586
6587 case InitializedEntity::EK_ArrayElement:
6588 // For subobjects, we look at the complete object.
6589 return getEntityLifetime(Entity->getParent(), InitField);
6590
6591 case InitializedEntity::EK_Base:
6592 // For subobjects, we look at the complete object.
6593 if (Entity->getParent())
6594 return getEntityLifetime(Entity->getParent(), InitField);
6595 return {InitField, LK_MemInitializer};
6596
6597 case InitializedEntity::EK_Delegating:
6598 // We can reach this case for aggregate initialization in a constructor:
6599 // struct A { int &&r; };
6600 // struct B : A { B() : A{0} {} };
6601 // In this case, use the outermost field decl as the context.
6602 return {InitField, LK_MemInitializer};
6603
6604 case InitializedEntity::EK_BlockElement:
6605 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6606 case InitializedEntity::EK_LambdaCapture:
6607 case InitializedEntity::EK_VectorElement:
6608 case InitializedEntity::EK_ComplexElement:
6609 return {nullptr, LK_FullExpression};
6610
6611 case InitializedEntity::EK_Exception:
6612 // FIXME: Can we diagnose lifetime problems with exceptions?
6613 return {nullptr, LK_FullExpression};
6614 }
6615 llvm_unreachable("unknown entity kind");
6616 }
6617
6618 namespace {
6619 enum ReferenceKind {
6620 /// Lifetime would be extended by a reference binding to a temporary.
6621 RK_ReferenceBinding,
6622 /// Lifetime would be extended by a std::initializer_list object binding to
6623 /// its backing array.
6624 RK_StdInitializerList,
6625 };
6626
6627 /// A temporary or local variable. This will be one of:
6628 /// * A MaterializeTemporaryExpr.
6629 /// * A DeclRefExpr whose declaration is a local.
6630 /// * An AddrLabelExpr.
6631 /// * A BlockExpr for a block with captures.
6632 using Local = Expr*;
6633
6634 /// Expressions we stepped over when looking for the local state. Any steps
6635 /// that would inhibit lifetime extension or take us out of subexpressions of
6636 /// the initializer are included.
6637 struct IndirectLocalPathEntry {
6638 enum EntryKind {
6639 DefaultInit,
6640 AddressOf,
6641 VarInit,
6642 LValToRVal,
6643 LifetimeBoundCall,
6644 GslReferenceInit,
6645 GslPointerInit
6646 } Kind;
6647 Expr *E;
6648 const Decl *D = nullptr;
IndirectLocalPathEntry__anona5eb8e390511::IndirectLocalPathEntry6649 IndirectLocalPathEntry() {}
IndirectLocalPathEntry__anona5eb8e390511::IndirectLocalPathEntry6650 IndirectLocalPathEntry(EntryKind K, Expr *E) : Kind(K), E(E) {}
IndirectLocalPathEntry__anona5eb8e390511::IndirectLocalPathEntry6651 IndirectLocalPathEntry(EntryKind K, Expr *E, const Decl *D)
6652 : Kind(K), E(E), D(D) {}
6653 };
6654
6655 using IndirectLocalPath = llvm::SmallVectorImpl<IndirectLocalPathEntry>;
6656
6657 struct RevertToOldSizeRAII {
6658 IndirectLocalPath &Path;
6659 unsigned OldSize = Path.size();
RevertToOldSizeRAII__anona5eb8e390511::RevertToOldSizeRAII6660 RevertToOldSizeRAII(IndirectLocalPath &Path) : Path(Path) {}
~RevertToOldSizeRAII__anona5eb8e390511::RevertToOldSizeRAII6661 ~RevertToOldSizeRAII() { Path.resize(OldSize); }
6662 };
6663
6664 using LocalVisitor = llvm::function_ref<bool(IndirectLocalPath &Path, Local L,
6665 ReferenceKind RK)>;
6666 }
6667
isVarOnPath(IndirectLocalPath & Path,VarDecl * VD)6668 static bool isVarOnPath(IndirectLocalPath &Path, VarDecl *VD) {
6669 for (auto E : Path)
6670 if (E.Kind == IndirectLocalPathEntry::VarInit && E.D == VD)
6671 return true;
6672 return false;
6673 }
6674
pathContainsInit(IndirectLocalPath & Path)6675 static bool pathContainsInit(IndirectLocalPath &Path) {
6676 return llvm::any_of(Path, [=](IndirectLocalPathEntry E) {
6677 return E.Kind == IndirectLocalPathEntry::DefaultInit ||
6678 E.Kind == IndirectLocalPathEntry::VarInit;
6679 });
6680 }
6681
6682 static void visitLocalsRetainedByInitializer(IndirectLocalPath &Path,
6683 Expr *Init, LocalVisitor Visit,
6684 bool RevisitSubinits,
6685 bool EnableLifetimeWarnings);
6686
6687 static void visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
6688 Expr *Init, ReferenceKind RK,
6689 LocalVisitor Visit,
6690 bool EnableLifetimeWarnings);
6691
isRecordWithAttr(QualType Type)6692 template <typename T> static bool isRecordWithAttr(QualType Type) {
6693 if (auto *RD = Type->getAsCXXRecordDecl())
6694 return RD->hasAttr<T>();
6695 return false;
6696 }
6697
6698 // Decl::isInStdNamespace will return false for iterators in some STL
6699 // implementations due to them being defined in a namespace outside of the std
6700 // namespace.
isInStlNamespace(const Decl * D)6701 static bool isInStlNamespace(const Decl *D) {
6702 const DeclContext *DC = D->getDeclContext();
6703 if (!DC)
6704 return false;
6705 if (const auto *ND = dyn_cast<NamespaceDecl>(DC))
6706 if (const IdentifierInfo *II = ND->getIdentifier()) {
6707 StringRef Name = II->getName();
6708 if (Name.size() >= 2 && Name.front() == '_' &&
6709 (Name[1] == '_' || isUppercase(Name[1])))
6710 return true;
6711 }
6712
6713 return DC->isStdNamespace();
6714 }
6715
shouldTrackImplicitObjectArg(const CXXMethodDecl * Callee)6716 static bool shouldTrackImplicitObjectArg(const CXXMethodDecl *Callee) {
6717 if (auto *Conv = dyn_cast_or_null<CXXConversionDecl>(Callee))
6718 if (isRecordWithAttr<PointerAttr>(Conv->getConversionType()))
6719 return true;
6720 if (!isInStlNamespace(Callee->getParent()))
6721 return false;
6722 if (!isRecordWithAttr<PointerAttr>(Callee->getThisObjectType()) &&
6723 !isRecordWithAttr<OwnerAttr>(Callee->getThisObjectType()))
6724 return false;
6725 if (Callee->getReturnType()->isPointerType() ||
6726 isRecordWithAttr<PointerAttr>(Callee->getReturnType())) {
6727 if (!Callee->getIdentifier())
6728 return false;
6729 return llvm::StringSwitch<bool>(Callee->getName())
6730 .Cases("begin", "rbegin", "cbegin", "crbegin", true)
6731 .Cases("end", "rend", "cend", "crend", true)
6732 .Cases("c_str", "data", "get", true)
6733 // Map and set types.
6734 .Cases("find", "equal_range", "lower_bound", "upper_bound", true)
6735 .Default(false);
6736 } else if (Callee->getReturnType()->isReferenceType()) {
6737 if (!Callee->getIdentifier()) {
6738 auto OO = Callee->getOverloadedOperator();
6739 return OO == OverloadedOperatorKind::OO_Subscript ||
6740 OO == OverloadedOperatorKind::OO_Star;
6741 }
6742 return llvm::StringSwitch<bool>(Callee->getName())
6743 .Cases("front", "back", "at", "top", "value", true)
6744 .Default(false);
6745 }
6746 return false;
6747 }
6748
shouldTrackFirstArgument(const FunctionDecl * FD)6749 static bool shouldTrackFirstArgument(const FunctionDecl *FD) {
6750 if (!FD->getIdentifier() || FD->getNumParams() != 1)
6751 return false;
6752 const auto *RD = FD->getParamDecl(0)->getType()->getPointeeCXXRecordDecl();
6753 if (!FD->isInStdNamespace() || !RD || !RD->isInStdNamespace())
6754 return false;
6755 if (!isRecordWithAttr<PointerAttr>(QualType(RD->getTypeForDecl(), 0)) &&
6756 !isRecordWithAttr<OwnerAttr>(QualType(RD->getTypeForDecl(), 0)))
6757 return false;
6758 if (FD->getReturnType()->isPointerType() ||
6759 isRecordWithAttr<PointerAttr>(FD->getReturnType())) {
6760 return llvm::StringSwitch<bool>(FD->getName())
6761 .Cases("begin", "rbegin", "cbegin", "crbegin", true)
6762 .Cases("end", "rend", "cend", "crend", true)
6763 .Case("data", true)
6764 .Default(false);
6765 } else if (FD->getReturnType()->isReferenceType()) {
6766 return llvm::StringSwitch<bool>(FD->getName())
6767 .Cases("get", "any_cast", true)
6768 .Default(false);
6769 }
6770 return false;
6771 }
6772
handleGslAnnotatedTypes(IndirectLocalPath & Path,Expr * Call,LocalVisitor Visit)6773 static void handleGslAnnotatedTypes(IndirectLocalPath &Path, Expr *Call,
6774 LocalVisitor Visit) {
6775 auto VisitPointerArg = [&](const Decl *D, Expr *Arg, bool Value) {
6776 // We are not interested in the temporary base objects of gsl Pointers:
6777 // Temp().ptr; // Here ptr might not dangle.
6778 if (isa<MemberExpr>(Arg->IgnoreImpCasts()))
6779 return;
6780 // Once we initialized a value with a reference, it can no longer dangle.
6781 if (!Value) {
6782 for (auto It = Path.rbegin(), End = Path.rend(); It != End; ++It) {
6783 if (It->Kind == IndirectLocalPathEntry::GslReferenceInit)
6784 continue;
6785 if (It->Kind == IndirectLocalPathEntry::GslPointerInit)
6786 return;
6787 break;
6788 }
6789 }
6790 Path.push_back({Value ? IndirectLocalPathEntry::GslPointerInit
6791 : IndirectLocalPathEntry::GslReferenceInit,
6792 Arg, D});
6793 if (Arg->isGLValue())
6794 visitLocalsRetainedByReferenceBinding(Path, Arg, RK_ReferenceBinding,
6795 Visit,
6796 /*EnableLifetimeWarnings=*/true);
6797 else
6798 visitLocalsRetainedByInitializer(Path, Arg, Visit, true,
6799 /*EnableLifetimeWarnings=*/true);
6800 Path.pop_back();
6801 };
6802
6803 if (auto *MCE = dyn_cast<CXXMemberCallExpr>(Call)) {
6804 const auto *MD = cast_or_null<CXXMethodDecl>(MCE->getDirectCallee());
6805 if (MD && shouldTrackImplicitObjectArg(MD))
6806 VisitPointerArg(MD, MCE->getImplicitObjectArgument(),
6807 !MD->getReturnType()->isReferenceType());
6808 return;
6809 } else if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(Call)) {
6810 FunctionDecl *Callee = OCE->getDirectCallee();
6811 if (Callee && Callee->isCXXInstanceMember() &&
6812 shouldTrackImplicitObjectArg(cast<CXXMethodDecl>(Callee)))
6813 VisitPointerArg(Callee, OCE->getArg(0),
6814 !Callee->getReturnType()->isReferenceType());
6815 return;
6816 } else if (auto *CE = dyn_cast<CallExpr>(Call)) {
6817 FunctionDecl *Callee = CE->getDirectCallee();
6818 if (Callee && shouldTrackFirstArgument(Callee))
6819 VisitPointerArg(Callee, CE->getArg(0),
6820 !Callee->getReturnType()->isReferenceType());
6821 return;
6822 }
6823
6824 if (auto *CCE = dyn_cast<CXXConstructExpr>(Call)) {
6825 const auto *Ctor = CCE->getConstructor();
6826 const CXXRecordDecl *RD = Ctor->getParent();
6827 if (CCE->getNumArgs() > 0 && RD->hasAttr<PointerAttr>())
6828 VisitPointerArg(Ctor->getParamDecl(0), CCE->getArgs()[0], true);
6829 }
6830 }
6831
implicitObjectParamIsLifetimeBound(const FunctionDecl * FD)6832 static bool implicitObjectParamIsLifetimeBound(const FunctionDecl *FD) {
6833 const TypeSourceInfo *TSI = FD->getTypeSourceInfo();
6834 if (!TSI)
6835 return false;
6836 // Don't declare this variable in the second operand of the for-statement;
6837 // GCC miscompiles that by ending its lifetime before evaluating the
6838 // third operand. See gcc.gnu.org/PR86769.
6839 AttributedTypeLoc ATL;
6840 for (TypeLoc TL = TSI->getTypeLoc();
6841 (ATL = TL.getAsAdjusted<AttributedTypeLoc>());
6842 TL = ATL.getModifiedLoc()) {
6843 if (ATL.getAttrAs<LifetimeBoundAttr>())
6844 return true;
6845 }
6846 return false;
6847 }
6848
visitLifetimeBoundArguments(IndirectLocalPath & Path,Expr * Call,LocalVisitor Visit)6849 static void visitLifetimeBoundArguments(IndirectLocalPath &Path, Expr *Call,
6850 LocalVisitor Visit) {
6851 const FunctionDecl *Callee;
6852 ArrayRef<Expr*> Args;
6853
6854 if (auto *CE = dyn_cast<CallExpr>(Call)) {
6855 Callee = CE->getDirectCallee();
6856 Args = llvm::makeArrayRef(CE->getArgs(), CE->getNumArgs());
6857 } else {
6858 auto *CCE = cast<CXXConstructExpr>(Call);
6859 Callee = CCE->getConstructor();
6860 Args = llvm::makeArrayRef(CCE->getArgs(), CCE->getNumArgs());
6861 }
6862 if (!Callee)
6863 return;
6864
6865 Expr *ObjectArg = nullptr;
6866 if (isa<CXXOperatorCallExpr>(Call) && Callee->isCXXInstanceMember()) {
6867 ObjectArg = Args[0];
6868 Args = Args.slice(1);
6869 } else if (auto *MCE = dyn_cast<CXXMemberCallExpr>(Call)) {
6870 ObjectArg = MCE->getImplicitObjectArgument();
6871 }
6872
6873 auto VisitLifetimeBoundArg = [&](const Decl *D, Expr *Arg) {
6874 Path.push_back({IndirectLocalPathEntry::LifetimeBoundCall, Arg, D});
6875 if (Arg->isGLValue())
6876 visitLocalsRetainedByReferenceBinding(Path, Arg, RK_ReferenceBinding,
6877 Visit,
6878 /*EnableLifetimeWarnings=*/false);
6879 else
6880 visitLocalsRetainedByInitializer(Path, Arg, Visit, true,
6881 /*EnableLifetimeWarnings=*/false);
6882 Path.pop_back();
6883 };
6884
6885 if (ObjectArg && implicitObjectParamIsLifetimeBound(Callee))
6886 VisitLifetimeBoundArg(Callee, ObjectArg);
6887
6888 for (unsigned I = 0,
6889 N = std::min<unsigned>(Callee->getNumParams(), Args.size());
6890 I != N; ++I) {
6891 if (Callee->getParamDecl(I)->hasAttr<LifetimeBoundAttr>())
6892 VisitLifetimeBoundArg(Callee->getParamDecl(I), Args[I]);
6893 }
6894 }
6895
6896 /// Visit the locals that would be reachable through a reference bound to the
6897 /// glvalue expression \c Init.
visitLocalsRetainedByReferenceBinding(IndirectLocalPath & Path,Expr * Init,ReferenceKind RK,LocalVisitor Visit,bool EnableLifetimeWarnings)6898 static void visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
6899 Expr *Init, ReferenceKind RK,
6900 LocalVisitor Visit,
6901 bool EnableLifetimeWarnings) {
6902 RevertToOldSizeRAII RAII(Path);
6903
6904 // Walk past any constructs which we can lifetime-extend across.
6905 Expr *Old;
6906 do {
6907 Old = Init;
6908
6909 if (auto *FE = dyn_cast<FullExpr>(Init))
6910 Init = FE->getSubExpr();
6911
6912 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
6913 // If this is just redundant braces around an initializer, step over it.
6914 if (ILE->isTransparent())
6915 Init = ILE->getInit(0);
6916 }
6917
6918 // Step over any subobject adjustments; we may have a materialized
6919 // temporary inside them.
6920 Init = const_cast<Expr *>(Init->skipRValueSubobjectAdjustments());
6921
6922 // Per current approach for DR1376, look through casts to reference type
6923 // when performing lifetime extension.
6924 if (CastExpr *CE = dyn_cast<CastExpr>(Init))
6925 if (CE->getSubExpr()->isGLValue())
6926 Init = CE->getSubExpr();
6927
6928 // Per the current approach for DR1299, look through array element access
6929 // on array glvalues when performing lifetime extension.
6930 if (auto *ASE = dyn_cast<ArraySubscriptExpr>(Init)) {
6931 Init = ASE->getBase();
6932 auto *ICE = dyn_cast<ImplicitCastExpr>(Init);
6933 if (ICE && ICE->getCastKind() == CK_ArrayToPointerDecay)
6934 Init = ICE->getSubExpr();
6935 else
6936 // We can't lifetime extend through this but we might still find some
6937 // retained temporaries.
6938 return visitLocalsRetainedByInitializer(Path, Init, Visit, true,
6939 EnableLifetimeWarnings);
6940 }
6941
6942 // Step into CXXDefaultInitExprs so we can diagnose cases where a
6943 // constructor inherits one as an implicit mem-initializer.
6944 if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Init)) {
6945 Path.push_back(
6946 {IndirectLocalPathEntry::DefaultInit, DIE, DIE->getField()});
6947 Init = DIE->getExpr();
6948 }
6949 } while (Init != Old);
6950
6951 if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(Init)) {
6952 if (Visit(Path, Local(MTE), RK))
6953 visitLocalsRetainedByInitializer(Path, MTE->getSubExpr(), Visit, true,
6954 EnableLifetimeWarnings);
6955 }
6956
6957 if (isa<CallExpr>(Init)) {
6958 if (EnableLifetimeWarnings)
6959 handleGslAnnotatedTypes(Path, Init, Visit);
6960 return visitLifetimeBoundArguments(Path, Init, Visit);
6961 }
6962
6963 switch (Init->getStmtClass()) {
6964 case Stmt::DeclRefExprClass: {
6965 // If we find the name of a local non-reference parameter, we could have a
6966 // lifetime problem.
6967 auto *DRE = cast<DeclRefExpr>(Init);
6968 auto *VD = dyn_cast<VarDecl>(DRE->getDecl());
6969 if (VD && VD->hasLocalStorage() &&
6970 !DRE->refersToEnclosingVariableOrCapture()) {
6971 if (!VD->getType()->isReferenceType()) {
6972 Visit(Path, Local(DRE), RK);
6973 } else if (isa<ParmVarDecl>(DRE->getDecl())) {
6974 // The lifetime of a reference parameter is unknown; assume it's OK
6975 // for now.
6976 break;
6977 } else if (VD->getInit() && !isVarOnPath(Path, VD)) {
6978 Path.push_back({IndirectLocalPathEntry::VarInit, DRE, VD});
6979 visitLocalsRetainedByReferenceBinding(Path, VD->getInit(),
6980 RK_ReferenceBinding, Visit,
6981 EnableLifetimeWarnings);
6982 }
6983 }
6984 break;
6985 }
6986
6987 case Stmt::UnaryOperatorClass: {
6988 // The only unary operator that make sense to handle here
6989 // is Deref. All others don't resolve to a "name." This includes
6990 // handling all sorts of rvalues passed to a unary operator.
6991 const UnaryOperator *U = cast<UnaryOperator>(Init);
6992 if (U->getOpcode() == UO_Deref)
6993 visitLocalsRetainedByInitializer(Path, U->getSubExpr(), Visit, true,
6994 EnableLifetimeWarnings);
6995 break;
6996 }
6997
6998 case Stmt::OMPArraySectionExprClass: {
6999 visitLocalsRetainedByInitializer(Path,
7000 cast<OMPArraySectionExpr>(Init)->getBase(),
7001 Visit, true, EnableLifetimeWarnings);
7002 break;
7003 }
7004
7005 case Stmt::ConditionalOperatorClass:
7006 case Stmt::BinaryConditionalOperatorClass: {
7007 auto *C = cast<AbstractConditionalOperator>(Init);
7008 if (!C->getTrueExpr()->getType()->isVoidType())
7009 visitLocalsRetainedByReferenceBinding(Path, C->getTrueExpr(), RK, Visit,
7010 EnableLifetimeWarnings);
7011 if (!C->getFalseExpr()->getType()->isVoidType())
7012 visitLocalsRetainedByReferenceBinding(Path, C->getFalseExpr(), RK, Visit,
7013 EnableLifetimeWarnings);
7014 break;
7015 }
7016
7017 // FIXME: Visit the left-hand side of an -> or ->*.
7018
7019 default:
7020 break;
7021 }
7022 }
7023
7024 /// Visit the locals that would be reachable through an object initialized by
7025 /// the prvalue expression \c Init.
visitLocalsRetainedByInitializer(IndirectLocalPath & Path,Expr * Init,LocalVisitor Visit,bool RevisitSubinits,bool EnableLifetimeWarnings)7026 static void visitLocalsRetainedByInitializer(IndirectLocalPath &Path,
7027 Expr *Init, LocalVisitor Visit,
7028 bool RevisitSubinits,
7029 bool EnableLifetimeWarnings) {
7030 RevertToOldSizeRAII RAII(Path);
7031
7032 Expr *Old;
7033 do {
7034 Old = Init;
7035
7036 // Step into CXXDefaultInitExprs so we can diagnose cases where a
7037 // constructor inherits one as an implicit mem-initializer.
7038 if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Init)) {
7039 Path.push_back({IndirectLocalPathEntry::DefaultInit, DIE, DIE->getField()});
7040 Init = DIE->getExpr();
7041 }
7042
7043 if (auto *FE = dyn_cast<FullExpr>(Init))
7044 Init = FE->getSubExpr();
7045
7046 // Dig out the expression which constructs the extended temporary.
7047 Init = const_cast<Expr *>(Init->skipRValueSubobjectAdjustments());
7048
7049 if (CXXBindTemporaryExpr *BTE = dyn_cast<CXXBindTemporaryExpr>(Init))
7050 Init = BTE->getSubExpr();
7051
7052 Init = Init->IgnoreParens();
7053
7054 // Step over value-preserving rvalue casts.
7055 if (auto *CE = dyn_cast<CastExpr>(Init)) {
7056 switch (CE->getCastKind()) {
7057 case CK_LValueToRValue:
7058 // If we can match the lvalue to a const object, we can look at its
7059 // initializer.
7060 Path.push_back({IndirectLocalPathEntry::LValToRVal, CE});
7061 return visitLocalsRetainedByReferenceBinding(
7062 Path, Init, RK_ReferenceBinding,
7063 [&](IndirectLocalPath &Path, Local L, ReferenceKind RK) -> bool {
7064 if (auto *DRE = dyn_cast<DeclRefExpr>(L)) {
7065 auto *VD = dyn_cast<VarDecl>(DRE->getDecl());
7066 if (VD && VD->getType().isConstQualified() && VD->getInit() &&
7067 !isVarOnPath(Path, VD)) {
7068 Path.push_back({IndirectLocalPathEntry::VarInit, DRE, VD});
7069 visitLocalsRetainedByInitializer(Path, VD->getInit(), Visit, true,
7070 EnableLifetimeWarnings);
7071 }
7072 } else if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(L)) {
7073 if (MTE->getType().isConstQualified())
7074 visitLocalsRetainedByInitializer(Path, MTE->getSubExpr(), Visit,
7075 true, EnableLifetimeWarnings);
7076 }
7077 return false;
7078 }, EnableLifetimeWarnings);
7079
7080 // We assume that objects can be retained by pointers cast to integers,
7081 // but not if the integer is cast to floating-point type or to _Complex.
7082 // We assume that casts to 'bool' do not preserve enough information to
7083 // retain a local object.
7084 case CK_NoOp:
7085 case CK_BitCast:
7086 case CK_BaseToDerived:
7087 case CK_DerivedToBase:
7088 case CK_UncheckedDerivedToBase:
7089 case CK_Dynamic:
7090 case CK_ToUnion:
7091 case CK_UserDefinedConversion:
7092 case CK_ConstructorConversion:
7093 case CK_IntegralToPointer:
7094 case CK_PointerToIntegral:
7095 case CK_VectorSplat:
7096 case CK_IntegralCast:
7097 case CK_CPointerToObjCPointerCast:
7098 case CK_BlockPointerToObjCPointerCast:
7099 case CK_AnyPointerToBlockPointerCast:
7100 case CK_AddressSpaceConversion:
7101 break;
7102
7103 case CK_ArrayToPointerDecay:
7104 // Model array-to-pointer decay as taking the address of the array
7105 // lvalue.
7106 Path.push_back({IndirectLocalPathEntry::AddressOf, CE});
7107 return visitLocalsRetainedByReferenceBinding(Path, CE->getSubExpr(),
7108 RK_ReferenceBinding, Visit,
7109 EnableLifetimeWarnings);
7110
7111 default:
7112 return;
7113 }
7114
7115 Init = CE->getSubExpr();
7116 }
7117 } while (Old != Init);
7118
7119 // C++17 [dcl.init.list]p6:
7120 // initializing an initializer_list object from the array extends the
7121 // lifetime of the array exactly like binding a reference to a temporary.
7122 if (auto *ILE = dyn_cast<CXXStdInitializerListExpr>(Init))
7123 return visitLocalsRetainedByReferenceBinding(Path, ILE->getSubExpr(),
7124 RK_StdInitializerList, Visit,
7125 EnableLifetimeWarnings);
7126
7127 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
7128 // We already visited the elements of this initializer list while
7129 // performing the initialization. Don't visit them again unless we've
7130 // changed the lifetime of the initialized entity.
7131 if (!RevisitSubinits)
7132 return;
7133
7134 if (ILE->isTransparent())
7135 return visitLocalsRetainedByInitializer(Path, ILE->getInit(0), Visit,
7136 RevisitSubinits,
7137 EnableLifetimeWarnings);
7138
7139 if (ILE->getType()->isArrayType()) {
7140 for (unsigned I = 0, N = ILE->getNumInits(); I != N; ++I)
7141 visitLocalsRetainedByInitializer(Path, ILE->getInit(I), Visit,
7142 RevisitSubinits,
7143 EnableLifetimeWarnings);
7144 return;
7145 }
7146
7147 if (CXXRecordDecl *RD = ILE->getType()->getAsCXXRecordDecl()) {
7148 assert(RD->isAggregate() && "aggregate init on non-aggregate");
7149
7150 // If we lifetime-extend a braced initializer which is initializing an
7151 // aggregate, and that aggregate contains reference members which are
7152 // bound to temporaries, those temporaries are also lifetime-extended.
7153 if (RD->isUnion() && ILE->getInitializedFieldInUnion() &&
7154 ILE->getInitializedFieldInUnion()->getType()->isReferenceType())
7155 visitLocalsRetainedByReferenceBinding(Path, ILE->getInit(0),
7156 RK_ReferenceBinding, Visit,
7157 EnableLifetimeWarnings);
7158 else {
7159 unsigned Index = 0;
7160 for (; Index < RD->getNumBases() && Index < ILE->getNumInits(); ++Index)
7161 visitLocalsRetainedByInitializer(Path, ILE->getInit(Index), Visit,
7162 RevisitSubinits,
7163 EnableLifetimeWarnings);
7164 for (const auto *I : RD->fields()) {
7165 if (Index >= ILE->getNumInits())
7166 break;
7167 if (I->isUnnamedBitfield())
7168 continue;
7169 Expr *SubInit = ILE->getInit(Index);
7170 if (I->getType()->isReferenceType())
7171 visitLocalsRetainedByReferenceBinding(Path, SubInit,
7172 RK_ReferenceBinding, Visit,
7173 EnableLifetimeWarnings);
7174 else
7175 // This might be either aggregate-initialization of a member or
7176 // initialization of a std::initializer_list object. Regardless,
7177 // we should recursively lifetime-extend that initializer.
7178 visitLocalsRetainedByInitializer(Path, SubInit, Visit,
7179 RevisitSubinits,
7180 EnableLifetimeWarnings);
7181 ++Index;
7182 }
7183 }
7184 }
7185 return;
7186 }
7187
7188 // The lifetime of an init-capture is that of the closure object constructed
7189 // by a lambda-expression.
7190 if (auto *LE = dyn_cast<LambdaExpr>(Init)) {
7191 for (Expr *E : LE->capture_inits()) {
7192 if (!E)
7193 continue;
7194 if (E->isGLValue())
7195 visitLocalsRetainedByReferenceBinding(Path, E, RK_ReferenceBinding,
7196 Visit, EnableLifetimeWarnings);
7197 else
7198 visitLocalsRetainedByInitializer(Path, E, Visit, true,
7199 EnableLifetimeWarnings);
7200 }
7201 }
7202
7203 if (isa<CallExpr>(Init) || isa<CXXConstructExpr>(Init)) {
7204 if (EnableLifetimeWarnings)
7205 handleGslAnnotatedTypes(Path, Init, Visit);
7206 return visitLifetimeBoundArguments(Path, Init, Visit);
7207 }
7208
7209 switch (Init->getStmtClass()) {
7210 case Stmt::UnaryOperatorClass: {
7211 auto *UO = cast<UnaryOperator>(Init);
7212 // If the initializer is the address of a local, we could have a lifetime
7213 // problem.
7214 if (UO->getOpcode() == UO_AddrOf) {
7215 // If this is &rvalue, then it's ill-formed and we have already diagnosed
7216 // it. Don't produce a redundant warning about the lifetime of the
7217 // temporary.
7218 if (isa<MaterializeTemporaryExpr>(UO->getSubExpr()))
7219 return;
7220
7221 Path.push_back({IndirectLocalPathEntry::AddressOf, UO});
7222 visitLocalsRetainedByReferenceBinding(Path, UO->getSubExpr(),
7223 RK_ReferenceBinding, Visit,
7224 EnableLifetimeWarnings);
7225 }
7226 break;
7227 }
7228
7229 case Stmt::BinaryOperatorClass: {
7230 // Handle pointer arithmetic.
7231 auto *BO = cast<BinaryOperator>(Init);
7232 BinaryOperatorKind BOK = BO->getOpcode();
7233 if (!BO->getType()->isPointerType() || (BOK != BO_Add && BOK != BO_Sub))
7234 break;
7235
7236 if (BO->getLHS()->getType()->isPointerType())
7237 visitLocalsRetainedByInitializer(Path, BO->getLHS(), Visit, true,
7238 EnableLifetimeWarnings);
7239 else if (BO->getRHS()->getType()->isPointerType())
7240 visitLocalsRetainedByInitializer(Path, BO->getRHS(), Visit, true,
7241 EnableLifetimeWarnings);
7242 break;
7243 }
7244
7245 case Stmt::ConditionalOperatorClass:
7246 case Stmt::BinaryConditionalOperatorClass: {
7247 auto *C = cast<AbstractConditionalOperator>(Init);
7248 // In C++, we can have a throw-expression operand, which has 'void' type
7249 // and isn't interesting from a lifetime perspective.
7250 if (!C->getTrueExpr()->getType()->isVoidType())
7251 visitLocalsRetainedByInitializer(Path, C->getTrueExpr(), Visit, true,
7252 EnableLifetimeWarnings);
7253 if (!C->getFalseExpr()->getType()->isVoidType())
7254 visitLocalsRetainedByInitializer(Path, C->getFalseExpr(), Visit, true,
7255 EnableLifetimeWarnings);
7256 break;
7257 }
7258
7259 case Stmt::BlockExprClass:
7260 if (cast<BlockExpr>(Init)->getBlockDecl()->hasCaptures()) {
7261 // This is a local block, whose lifetime is that of the function.
7262 Visit(Path, Local(cast<BlockExpr>(Init)), RK_ReferenceBinding);
7263 }
7264 break;
7265
7266 case Stmt::AddrLabelExprClass:
7267 // We want to warn if the address of a label would escape the function.
7268 Visit(Path, Local(cast<AddrLabelExpr>(Init)), RK_ReferenceBinding);
7269 break;
7270
7271 default:
7272 break;
7273 }
7274 }
7275
7276 /// Determine whether this is an indirect path to a temporary that we are
7277 /// supposed to lifetime-extend along (but don't).
shouldLifetimeExtendThroughPath(const IndirectLocalPath & Path)7278 static bool shouldLifetimeExtendThroughPath(const IndirectLocalPath &Path) {
7279 for (auto Elem : Path) {
7280 if (Elem.Kind != IndirectLocalPathEntry::DefaultInit)
7281 return false;
7282 }
7283 return true;
7284 }
7285
7286 /// Find the range for the first interesting entry in the path at or after I.
nextPathEntryRange(const IndirectLocalPath & Path,unsigned I,Expr * E)7287 static SourceRange nextPathEntryRange(const IndirectLocalPath &Path, unsigned I,
7288 Expr *E) {
7289 for (unsigned N = Path.size(); I != N; ++I) {
7290 switch (Path[I].Kind) {
7291 case IndirectLocalPathEntry::AddressOf:
7292 case IndirectLocalPathEntry::LValToRVal:
7293 case IndirectLocalPathEntry::LifetimeBoundCall:
7294 case IndirectLocalPathEntry::GslReferenceInit:
7295 case IndirectLocalPathEntry::GslPointerInit:
7296 // These exist primarily to mark the path as not permitting or
7297 // supporting lifetime extension.
7298 break;
7299
7300 case IndirectLocalPathEntry::VarInit:
7301 if (cast<VarDecl>(Path[I].D)->isImplicit())
7302 return SourceRange();
7303 LLVM_FALLTHROUGH;
7304 case IndirectLocalPathEntry::DefaultInit:
7305 return Path[I].E->getSourceRange();
7306 }
7307 }
7308 return E->getSourceRange();
7309 }
7310
pathOnlyInitializesGslPointer(IndirectLocalPath & Path)7311 static bool pathOnlyInitializesGslPointer(IndirectLocalPath &Path) {
7312 for (auto It = Path.rbegin(), End = Path.rend(); It != End; ++It) {
7313 if (It->Kind == IndirectLocalPathEntry::VarInit)
7314 continue;
7315 if (It->Kind == IndirectLocalPathEntry::AddressOf)
7316 continue;
7317 return It->Kind == IndirectLocalPathEntry::GslPointerInit ||
7318 It->Kind == IndirectLocalPathEntry::GslReferenceInit;
7319 }
7320 return false;
7321 }
7322
checkInitializerLifetime(const InitializedEntity & Entity,Expr * Init)7323 void Sema::checkInitializerLifetime(const InitializedEntity &Entity,
7324 Expr *Init) {
7325 LifetimeResult LR = getEntityLifetime(&Entity);
7326 LifetimeKind LK = LR.getInt();
7327 const InitializedEntity *ExtendingEntity = LR.getPointer();
7328
7329 // If this entity doesn't have an interesting lifetime, don't bother looking
7330 // for temporaries within its initializer.
7331 if (LK == LK_FullExpression)
7332 return;
7333
7334 auto TemporaryVisitor = [&](IndirectLocalPath &Path, Local L,
7335 ReferenceKind RK) -> bool {
7336 SourceRange DiagRange = nextPathEntryRange(Path, 0, L);
7337 SourceLocation DiagLoc = DiagRange.getBegin();
7338
7339 auto *MTE = dyn_cast<MaterializeTemporaryExpr>(L);
7340
7341 bool IsGslPtrInitWithGslTempOwner = false;
7342 bool IsLocalGslOwner = false;
7343 if (pathOnlyInitializesGslPointer(Path)) {
7344 if (isa<DeclRefExpr>(L)) {
7345 // We do not want to follow the references when returning a pointer originating
7346 // from a local owner to avoid the following false positive:
7347 // int &p = *localUniquePtr;
7348 // someContainer.add(std::move(localUniquePtr));
7349 // return p;
7350 IsLocalGslOwner = isRecordWithAttr<OwnerAttr>(L->getType());
7351 if (pathContainsInit(Path) || !IsLocalGslOwner)
7352 return false;
7353 } else {
7354 IsGslPtrInitWithGslTempOwner = MTE && !MTE->getExtendingDecl() &&
7355 isRecordWithAttr<OwnerAttr>(MTE->getType());
7356 // Skipping a chain of initializing gsl::Pointer annotated objects.
7357 // We are looking only for the final source to find out if it was
7358 // a local or temporary owner or the address of a local variable/param.
7359 if (!IsGslPtrInitWithGslTempOwner)
7360 return true;
7361 }
7362 }
7363
7364 switch (LK) {
7365 case LK_FullExpression:
7366 llvm_unreachable("already handled this");
7367
7368 case LK_Extended: {
7369 if (!MTE) {
7370 // The initialized entity has lifetime beyond the full-expression,
7371 // and the local entity does too, so don't warn.
7372 //
7373 // FIXME: We should consider warning if a static / thread storage
7374 // duration variable retains an automatic storage duration local.
7375 return false;
7376 }
7377
7378 if (IsGslPtrInitWithGslTempOwner && DiagLoc.isValid()) {
7379 Diag(DiagLoc, diag::warn_dangling_lifetime_pointer) << DiagRange;
7380 return false;
7381 }
7382
7383 // Lifetime-extend the temporary.
7384 if (Path.empty()) {
7385 // Update the storage duration of the materialized temporary.
7386 // FIXME: Rebuild the expression instead of mutating it.
7387 MTE->setExtendingDecl(ExtendingEntity->getDecl(),
7388 ExtendingEntity->allocateManglingNumber());
7389 // Also visit the temporaries lifetime-extended by this initializer.
7390 return true;
7391 }
7392
7393 if (shouldLifetimeExtendThroughPath(Path)) {
7394 // We're supposed to lifetime-extend the temporary along this path (per
7395 // the resolution of DR1815), but we don't support that yet.
7396 //
7397 // FIXME: Properly handle this situation. Perhaps the easiest approach
7398 // would be to clone the initializer expression on each use that would
7399 // lifetime extend its temporaries.
7400 Diag(DiagLoc, diag::warn_unsupported_lifetime_extension)
7401 << RK << DiagRange;
7402 } else {
7403 // If the path goes through the initialization of a variable or field,
7404 // it can't possibly reach a temporary created in this full-expression.
7405 // We will have already diagnosed any problems with the initializer.
7406 if (pathContainsInit(Path))
7407 return false;
7408
7409 Diag(DiagLoc, diag::warn_dangling_variable)
7410 << RK << !Entity.getParent()
7411 << ExtendingEntity->getDecl()->isImplicit()
7412 << ExtendingEntity->getDecl() << Init->isGLValue() << DiagRange;
7413 }
7414 break;
7415 }
7416
7417 case LK_MemInitializer: {
7418 if (isa<MaterializeTemporaryExpr>(L)) {
7419 // Under C++ DR1696, if a mem-initializer (or a default member
7420 // initializer used by the absence of one) would lifetime-extend a
7421 // temporary, the program is ill-formed.
7422 if (auto *ExtendingDecl =
7423 ExtendingEntity ? ExtendingEntity->getDecl() : nullptr) {
7424 if (IsGslPtrInitWithGslTempOwner) {
7425 Diag(DiagLoc, diag::warn_dangling_lifetime_pointer_member)
7426 << ExtendingDecl << DiagRange;
7427 Diag(ExtendingDecl->getLocation(),
7428 diag::note_ref_or_ptr_member_declared_here)
7429 << true;
7430 return false;
7431 }
7432 bool IsSubobjectMember = ExtendingEntity != &Entity;
7433 Diag(DiagLoc, shouldLifetimeExtendThroughPath(Path)
7434 ? diag::err_dangling_member
7435 : diag::warn_dangling_member)
7436 << ExtendingDecl << IsSubobjectMember << RK << DiagRange;
7437 // Don't bother adding a note pointing to the field if we're inside
7438 // its default member initializer; our primary diagnostic points to
7439 // the same place in that case.
7440 if (Path.empty() ||
7441 Path.back().Kind != IndirectLocalPathEntry::DefaultInit) {
7442 Diag(ExtendingDecl->getLocation(),
7443 diag::note_lifetime_extending_member_declared_here)
7444 << RK << IsSubobjectMember;
7445 }
7446 } else {
7447 // We have a mem-initializer but no particular field within it; this
7448 // is either a base class or a delegating initializer directly
7449 // initializing the base-class from something that doesn't live long
7450 // enough.
7451 //
7452 // FIXME: Warn on this.
7453 return false;
7454 }
7455 } else {
7456 // Paths via a default initializer can only occur during error recovery
7457 // (there's no other way that a default initializer can refer to a
7458 // local). Don't produce a bogus warning on those cases.
7459 if (pathContainsInit(Path))
7460 return false;
7461
7462 // Suppress false positives for code like the one below:
7463 // Ctor(unique_ptr<T> up) : member(*up), member2(move(up)) {}
7464 if (IsLocalGslOwner && pathOnlyInitializesGslPointer(Path))
7465 return false;
7466
7467 auto *DRE = dyn_cast<DeclRefExpr>(L);
7468 auto *VD = DRE ? dyn_cast<VarDecl>(DRE->getDecl()) : nullptr;
7469 if (!VD) {
7470 // A member was initialized to a local block.
7471 // FIXME: Warn on this.
7472 return false;
7473 }
7474
7475 if (auto *Member =
7476 ExtendingEntity ? ExtendingEntity->getDecl() : nullptr) {
7477 bool IsPointer = !Member->getType()->isReferenceType();
7478 Diag(DiagLoc, IsPointer ? diag::warn_init_ptr_member_to_parameter_addr
7479 : diag::warn_bind_ref_member_to_parameter)
7480 << Member << VD << isa<ParmVarDecl>(VD) << DiagRange;
7481 Diag(Member->getLocation(),
7482 diag::note_ref_or_ptr_member_declared_here)
7483 << (unsigned)IsPointer;
7484 }
7485 }
7486 break;
7487 }
7488
7489 case LK_New:
7490 if (isa<MaterializeTemporaryExpr>(L)) {
7491 if (IsGslPtrInitWithGslTempOwner)
7492 Diag(DiagLoc, diag::warn_dangling_lifetime_pointer) << DiagRange;
7493 else
7494 Diag(DiagLoc, RK == RK_ReferenceBinding
7495 ? diag::warn_new_dangling_reference
7496 : diag::warn_new_dangling_initializer_list)
7497 << !Entity.getParent() << DiagRange;
7498 } else {
7499 // We can't determine if the allocation outlives the local declaration.
7500 return false;
7501 }
7502 break;
7503
7504 case LK_Return:
7505 case LK_StmtExprResult:
7506 if (auto *DRE = dyn_cast<DeclRefExpr>(L)) {
7507 // We can't determine if the local variable outlives the statement
7508 // expression.
7509 if (LK == LK_StmtExprResult)
7510 return false;
7511 Diag(DiagLoc, diag::warn_ret_stack_addr_ref)
7512 << Entity.getType()->isReferenceType() << DRE->getDecl()
7513 << isa<ParmVarDecl>(DRE->getDecl()) << DiagRange;
7514 } else if (isa<BlockExpr>(L)) {
7515 Diag(DiagLoc, diag::err_ret_local_block) << DiagRange;
7516 } else if (isa<AddrLabelExpr>(L)) {
7517 // Don't warn when returning a label from a statement expression.
7518 // Leaving the scope doesn't end its lifetime.
7519 if (LK == LK_StmtExprResult)
7520 return false;
7521 Diag(DiagLoc, diag::warn_ret_addr_label) << DiagRange;
7522 } else {
7523 Diag(DiagLoc, diag::warn_ret_local_temp_addr_ref)
7524 << Entity.getType()->isReferenceType() << DiagRange;
7525 }
7526 break;
7527 }
7528
7529 for (unsigned I = 0; I != Path.size(); ++I) {
7530 auto Elem = Path[I];
7531
7532 switch (Elem.Kind) {
7533 case IndirectLocalPathEntry::AddressOf:
7534 case IndirectLocalPathEntry::LValToRVal:
7535 // These exist primarily to mark the path as not permitting or
7536 // supporting lifetime extension.
7537 break;
7538
7539 case IndirectLocalPathEntry::LifetimeBoundCall:
7540 case IndirectLocalPathEntry::GslPointerInit:
7541 case IndirectLocalPathEntry::GslReferenceInit:
7542 // FIXME: Consider adding a note for these.
7543 break;
7544
7545 case IndirectLocalPathEntry::DefaultInit: {
7546 auto *FD = cast<FieldDecl>(Elem.D);
7547 Diag(FD->getLocation(), diag::note_init_with_default_member_initalizer)
7548 << FD << nextPathEntryRange(Path, I + 1, L);
7549 break;
7550 }
7551
7552 case IndirectLocalPathEntry::VarInit:
7553 const VarDecl *VD = cast<VarDecl>(Elem.D);
7554 Diag(VD->getLocation(), diag::note_local_var_initializer)
7555 << VD->getType()->isReferenceType()
7556 << VD->isImplicit() << VD->getDeclName()
7557 << nextPathEntryRange(Path, I + 1, L);
7558 break;
7559 }
7560 }
7561
7562 // We didn't lifetime-extend, so don't go any further; we don't need more
7563 // warnings or errors on inner temporaries within this one's initializer.
7564 return false;
7565 };
7566
7567 bool EnableLifetimeWarnings = !getDiagnostics().isIgnored(
7568 diag::warn_dangling_lifetime_pointer, SourceLocation());
7569 llvm::SmallVector<IndirectLocalPathEntry, 8> Path;
7570 if (Init->isGLValue())
7571 visitLocalsRetainedByReferenceBinding(Path, Init, RK_ReferenceBinding,
7572 TemporaryVisitor,
7573 EnableLifetimeWarnings);
7574 else
7575 visitLocalsRetainedByInitializer(Path, Init, TemporaryVisitor, false,
7576 EnableLifetimeWarnings);
7577 }
7578
7579 static void DiagnoseNarrowingInInitList(Sema &S,
7580 const ImplicitConversionSequence &ICS,
7581 QualType PreNarrowingType,
7582 QualType EntityType,
7583 const Expr *PostInit);
7584
7585 /// Provide warnings when std::move is used on construction.
CheckMoveOnConstruction(Sema & S,const Expr * InitExpr,bool IsReturnStmt)7586 static void CheckMoveOnConstruction(Sema &S, const Expr *InitExpr,
7587 bool IsReturnStmt) {
7588 if (!InitExpr)
7589 return;
7590
7591 if (S.inTemplateInstantiation())
7592 return;
7593
7594 QualType DestType = InitExpr->getType();
7595 if (!DestType->isRecordType())
7596 return;
7597
7598 unsigned DiagID = 0;
7599 if (IsReturnStmt) {
7600 const CXXConstructExpr *CCE =
7601 dyn_cast<CXXConstructExpr>(InitExpr->IgnoreParens());
7602 if (!CCE || CCE->getNumArgs() != 1)
7603 return;
7604
7605 if (!CCE->getConstructor()->isCopyOrMoveConstructor())
7606 return;
7607
7608 InitExpr = CCE->getArg(0)->IgnoreImpCasts();
7609 }
7610
7611 // Find the std::move call and get the argument.
7612 const CallExpr *CE = dyn_cast<CallExpr>(InitExpr->IgnoreParens());
7613 if (!CE || !CE->isCallToStdMove())
7614 return;
7615
7616 const Expr *Arg = CE->getArg(0)->IgnoreImplicit();
7617
7618 if (IsReturnStmt) {
7619 const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg->IgnoreParenImpCasts());
7620 if (!DRE || DRE->refersToEnclosingVariableOrCapture())
7621 return;
7622
7623 const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl());
7624 if (!VD || !VD->hasLocalStorage())
7625 return;
7626
7627 // __block variables are not moved implicitly.
7628 if (VD->hasAttr<BlocksAttr>())
7629 return;
7630
7631 QualType SourceType = VD->getType();
7632 if (!SourceType->isRecordType())
7633 return;
7634
7635 if (!S.Context.hasSameUnqualifiedType(DestType, SourceType)) {
7636 return;
7637 }
7638
7639 // If we're returning a function parameter, copy elision
7640 // is not possible.
7641 if (isa<ParmVarDecl>(VD))
7642 DiagID = diag::warn_redundant_move_on_return;
7643 else
7644 DiagID = diag::warn_pessimizing_move_on_return;
7645 } else {
7646 DiagID = diag::warn_pessimizing_move_on_initialization;
7647 const Expr *ArgStripped = Arg->IgnoreImplicit()->IgnoreParens();
7648 if (!ArgStripped->isRValue() || !ArgStripped->getType()->isRecordType())
7649 return;
7650 }
7651
7652 S.Diag(CE->getBeginLoc(), DiagID);
7653
7654 // Get all the locations for a fix-it. Don't emit the fix-it if any location
7655 // is within a macro.
7656 SourceLocation CallBegin = CE->getCallee()->getBeginLoc();
7657 if (CallBegin.isMacroID())
7658 return;
7659 SourceLocation RParen = CE->getRParenLoc();
7660 if (RParen.isMacroID())
7661 return;
7662 SourceLocation LParen;
7663 SourceLocation ArgLoc = Arg->getBeginLoc();
7664
7665 // Special testing for the argument location. Since the fix-it needs the
7666 // location right before the argument, the argument location can be in a
7667 // macro only if it is at the beginning of the macro.
7668 while (ArgLoc.isMacroID() &&
7669 S.getSourceManager().isAtStartOfImmediateMacroExpansion(ArgLoc)) {
7670 ArgLoc = S.getSourceManager().getImmediateExpansionRange(ArgLoc).getBegin();
7671 }
7672
7673 if (LParen.isMacroID())
7674 return;
7675
7676 LParen = ArgLoc.getLocWithOffset(-1);
7677
7678 S.Diag(CE->getBeginLoc(), diag::note_remove_move)
7679 << FixItHint::CreateRemoval(SourceRange(CallBegin, LParen))
7680 << FixItHint::CreateRemoval(SourceRange(RParen, RParen));
7681 }
7682
CheckForNullPointerDereference(Sema & S,const Expr * E)7683 static void CheckForNullPointerDereference(Sema &S, const Expr *E) {
7684 // Check to see if we are dereferencing a null pointer. If so, this is
7685 // undefined behavior, so warn about it. This only handles the pattern
7686 // "*null", which is a very syntactic check.
7687 if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E->IgnoreParenCasts()))
7688 if (UO->getOpcode() == UO_Deref &&
7689 UO->getSubExpr()->IgnoreParenCasts()->
7690 isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull)) {
7691 S.DiagRuntimeBehavior(UO->getOperatorLoc(), UO,
7692 S.PDiag(diag::warn_binding_null_to_reference)
7693 << UO->getSubExpr()->getSourceRange());
7694 }
7695 }
7696
7697 MaterializeTemporaryExpr *
CreateMaterializeTemporaryExpr(QualType T,Expr * Temporary,bool BoundToLvalueReference)7698 Sema::CreateMaterializeTemporaryExpr(QualType T, Expr *Temporary,
7699 bool BoundToLvalueReference) {
7700 auto MTE = new (Context)
7701 MaterializeTemporaryExpr(T, Temporary, BoundToLvalueReference);
7702
7703 // Order an ExprWithCleanups for lifetime marks.
7704 //
7705 // TODO: It'll be good to have a single place to check the access of the
7706 // destructor and generate ExprWithCleanups for various uses. Currently these
7707 // are done in both CreateMaterializeTemporaryExpr and MaybeBindToTemporary,
7708 // but there may be a chance to merge them.
7709 Cleanup.setExprNeedsCleanups(false);
7710 return MTE;
7711 }
7712
TemporaryMaterializationConversion(Expr * E)7713 ExprResult Sema::TemporaryMaterializationConversion(Expr *E) {
7714 // In C++98, we don't want to implicitly create an xvalue.
7715 // FIXME: This means that AST consumers need to deal with "prvalues" that
7716 // denote materialized temporaries. Maybe we should add another ValueKind
7717 // for "xvalue pretending to be a prvalue" for C++98 support.
7718 if (!E->isRValue() || !getLangOpts().CPlusPlus11)
7719 return E;
7720
7721 // C++1z [conv.rval]/1: T shall be a complete type.
7722 // FIXME: Does this ever matter (can we form a prvalue of incomplete type)?
7723 // If so, we should check for a non-abstract class type here too.
7724 QualType T = E->getType();
7725 if (RequireCompleteType(E->getExprLoc(), T, diag::err_incomplete_type))
7726 return ExprError();
7727
7728 return CreateMaterializeTemporaryExpr(E->getType(), E, false);
7729 }
7730
PerformQualificationConversion(Expr * E,QualType Ty,ExprValueKind VK,CheckedConversionKind CCK)7731 ExprResult Sema::PerformQualificationConversion(Expr *E, QualType Ty,
7732 ExprValueKind VK,
7733 CheckedConversionKind CCK) {
7734
7735 CastKind CK = CK_NoOp;
7736
7737 if (VK == VK_RValue) {
7738 auto PointeeTy = Ty->getPointeeType();
7739 auto ExprPointeeTy = E->getType()->getPointeeType();
7740 if (!PointeeTy.isNull() &&
7741 PointeeTy.getAddressSpace() != ExprPointeeTy.getAddressSpace())
7742 CK = CK_AddressSpaceConversion;
7743 } else if (Ty.getAddressSpace() != E->getType().getAddressSpace()) {
7744 CK = CK_AddressSpaceConversion;
7745 }
7746
7747 return ImpCastExprToType(E, Ty, CK, VK, /*BasePath=*/nullptr, CCK);
7748 }
7749
Perform(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Args,QualType * ResultType)7750 ExprResult InitializationSequence::Perform(Sema &S,
7751 const InitializedEntity &Entity,
7752 const InitializationKind &Kind,
7753 MultiExprArg Args,
7754 QualType *ResultType) {
7755 if (Failed()) {
7756 Diagnose(S, Entity, Kind, Args);
7757 return ExprError();
7758 }
7759 if (!ZeroInitializationFixit.empty()) {
7760 unsigned DiagID = diag::err_default_init_const;
7761 if (Decl *D = Entity.getDecl())
7762 if (S.getLangOpts().MSVCCompat && D->hasAttr<SelectAnyAttr>())
7763 DiagID = diag::ext_default_init_const;
7764
7765 // The initialization would have succeeded with this fixit. Since the fixit
7766 // is on the error, we need to build a valid AST in this case, so this isn't
7767 // handled in the Failed() branch above.
7768 QualType DestType = Entity.getType();
7769 S.Diag(Kind.getLocation(), DiagID)
7770 << DestType << (bool)DestType->getAs<RecordType>()
7771 << FixItHint::CreateInsertion(ZeroInitializationFixitLoc,
7772 ZeroInitializationFixit);
7773 }
7774
7775 if (getKind() == DependentSequence) {
7776 // If the declaration is a non-dependent, incomplete array type
7777 // that has an initializer, then its type will be completed once
7778 // the initializer is instantiated.
7779 if (ResultType && !Entity.getType()->isDependentType() &&
7780 Args.size() == 1) {
7781 QualType DeclType = Entity.getType();
7782 if (const IncompleteArrayType *ArrayT
7783 = S.Context.getAsIncompleteArrayType(DeclType)) {
7784 // FIXME: We don't currently have the ability to accurately
7785 // compute the length of an initializer list without
7786 // performing full type-checking of the initializer list
7787 // (since we have to determine where braces are implicitly
7788 // introduced and such). So, we fall back to making the array
7789 // type a dependently-sized array type with no specified
7790 // bound.
7791 if (isa<InitListExpr>((Expr *)Args[0])) {
7792 SourceRange Brackets;
7793
7794 // Scavange the location of the brackets from the entity, if we can.
7795 if (auto *DD = dyn_cast_or_null<DeclaratorDecl>(Entity.getDecl())) {
7796 if (TypeSourceInfo *TInfo = DD->getTypeSourceInfo()) {
7797 TypeLoc TL = TInfo->getTypeLoc();
7798 if (IncompleteArrayTypeLoc ArrayLoc =
7799 TL.getAs<IncompleteArrayTypeLoc>())
7800 Brackets = ArrayLoc.getBracketsRange();
7801 }
7802 }
7803
7804 *ResultType
7805 = S.Context.getDependentSizedArrayType(ArrayT->getElementType(),
7806 /*NumElts=*/nullptr,
7807 ArrayT->getSizeModifier(),
7808 ArrayT->getIndexTypeCVRQualifiers(),
7809 Brackets);
7810 }
7811
7812 }
7813 }
7814 if (Kind.getKind() == InitializationKind::IK_Direct &&
7815 !Kind.isExplicitCast()) {
7816 // Rebuild the ParenListExpr.
7817 SourceRange ParenRange = Kind.getParenOrBraceRange();
7818 return S.ActOnParenListExpr(ParenRange.getBegin(), ParenRange.getEnd(),
7819 Args);
7820 }
7821 assert(Kind.getKind() == InitializationKind::IK_Copy ||
7822 Kind.isExplicitCast() ||
7823 Kind.getKind() == InitializationKind::IK_DirectList);
7824 return ExprResult(Args[0]);
7825 }
7826
7827 // No steps means no initialization.
7828 if (Steps.empty())
7829 return ExprResult((Expr *)nullptr);
7830
7831 if (S.getLangOpts().CPlusPlus11 && Entity.getType()->isReferenceType() &&
7832 Args.size() == 1 && isa<InitListExpr>(Args[0]) &&
7833 !Entity.isParameterKind()) {
7834 // Produce a C++98 compatibility warning if we are initializing a reference
7835 // from an initializer list. For parameters, we produce a better warning
7836 // elsewhere.
7837 Expr *Init = Args[0];
7838 S.Diag(Init->getBeginLoc(), diag::warn_cxx98_compat_reference_list_init)
7839 << Init->getSourceRange();
7840 }
7841
7842 // OpenCL v2.0 s6.13.11.1. atomic variables can be initialized in global scope
7843 QualType ETy = Entity.getType();
7844 bool HasGlobalAS = ETy.hasAddressSpace() &&
7845 ETy.getAddressSpace() == LangAS::opencl_global;
7846
7847 if (S.getLangOpts().OpenCLVersion >= 200 &&
7848 ETy->isAtomicType() && !HasGlobalAS &&
7849 Entity.getKind() == InitializedEntity::EK_Variable && Args.size() > 0) {
7850 S.Diag(Args[0]->getBeginLoc(), diag::err_opencl_atomic_init)
7851 << 1
7852 << SourceRange(Entity.getDecl()->getBeginLoc(), Args[0]->getEndLoc());
7853 return ExprError();
7854 }
7855
7856 QualType DestType = Entity.getType().getNonReferenceType();
7857 // FIXME: Ugly hack around the fact that Entity.getType() is not
7858 // the same as Entity.getDecl()->getType() in cases involving type merging,
7859 // and we want latter when it makes sense.
7860 if (ResultType)
7861 *ResultType = Entity.getDecl() ? Entity.getDecl()->getType() :
7862 Entity.getType();
7863
7864 ExprResult CurInit((Expr *)nullptr);
7865 SmallVector<Expr*, 4> ArrayLoopCommonExprs;
7866
7867 // For initialization steps that start with a single initializer,
7868 // grab the only argument out the Args and place it into the "current"
7869 // initializer.
7870 switch (Steps.front().Kind) {
7871 case SK_ResolveAddressOfOverloadedFunction:
7872 case SK_CastDerivedToBaseRValue:
7873 case SK_CastDerivedToBaseXValue:
7874 case SK_CastDerivedToBaseLValue:
7875 case SK_BindReference:
7876 case SK_BindReferenceToTemporary:
7877 case SK_FinalCopy:
7878 case SK_ExtraneousCopyToTemporary:
7879 case SK_UserConversion:
7880 case SK_QualificationConversionLValue:
7881 case SK_QualificationConversionXValue:
7882 case SK_QualificationConversionRValue:
7883 case SK_AtomicConversion:
7884 case SK_ConversionSequence:
7885 case SK_ConversionSequenceNoNarrowing:
7886 case SK_ListInitialization:
7887 case SK_UnwrapInitList:
7888 case SK_RewrapInitList:
7889 case SK_CAssignment:
7890 case SK_StringInit:
7891 case SK_ObjCObjectConversion:
7892 case SK_ArrayLoopIndex:
7893 case SK_ArrayLoopInit:
7894 case SK_ArrayInit:
7895 case SK_GNUArrayInit:
7896 case SK_ParenthesizedArrayInit:
7897 case SK_PassByIndirectCopyRestore:
7898 case SK_PassByIndirectRestore:
7899 case SK_ProduceObjCObject:
7900 case SK_StdInitializerList:
7901 case SK_OCLSamplerInit:
7902 case SK_OCLZeroOpaqueType: {
7903 assert(Args.size() == 1);
7904 CurInit = Args[0];
7905 if (!CurInit.get()) return ExprError();
7906 break;
7907 }
7908
7909 case SK_ConstructorInitialization:
7910 case SK_ConstructorInitializationFromList:
7911 case SK_StdInitializerListConstructorCall:
7912 case SK_ZeroInitialization:
7913 break;
7914 }
7915
7916 // Promote from an unevaluated context to an unevaluated list context in
7917 // C++11 list-initialization; we need to instantiate entities usable in
7918 // constant expressions here in order to perform narrowing checks =(
7919 EnterExpressionEvaluationContext Evaluated(
7920 S, EnterExpressionEvaluationContext::InitList,
7921 CurInit.get() && isa<InitListExpr>(CurInit.get()));
7922
7923 // C++ [class.abstract]p2:
7924 // no objects of an abstract class can be created except as subobjects
7925 // of a class derived from it
7926 auto checkAbstractType = [&](QualType T) -> bool {
7927 if (Entity.getKind() == InitializedEntity::EK_Base ||
7928 Entity.getKind() == InitializedEntity::EK_Delegating)
7929 return false;
7930 return S.RequireNonAbstractType(Kind.getLocation(), T,
7931 diag::err_allocation_of_abstract_type);
7932 };
7933
7934 // Walk through the computed steps for the initialization sequence,
7935 // performing the specified conversions along the way.
7936 bool ConstructorInitRequiresZeroInit = false;
7937 for (step_iterator Step = step_begin(), StepEnd = step_end();
7938 Step != StepEnd; ++Step) {
7939 if (CurInit.isInvalid())
7940 return ExprError();
7941
7942 QualType SourceType = CurInit.get() ? CurInit.get()->getType() : QualType();
7943
7944 switch (Step->Kind) {
7945 case SK_ResolveAddressOfOverloadedFunction:
7946 // Overload resolution determined which function invoke; update the
7947 // initializer to reflect that choice.
7948 S.CheckAddressOfMemberAccess(CurInit.get(), Step->Function.FoundDecl);
7949 if (S.DiagnoseUseOfDecl(Step->Function.FoundDecl, Kind.getLocation()))
7950 return ExprError();
7951 CurInit = S.FixOverloadedFunctionReference(CurInit,
7952 Step->Function.FoundDecl,
7953 Step->Function.Function);
7954 break;
7955
7956 case SK_CastDerivedToBaseRValue:
7957 case SK_CastDerivedToBaseXValue:
7958 case SK_CastDerivedToBaseLValue: {
7959 // We have a derived-to-base cast that produces either an rvalue or an
7960 // lvalue. Perform that cast.
7961
7962 CXXCastPath BasePath;
7963
7964 // Casts to inaccessible base classes are allowed with C-style casts.
7965 bool IgnoreBaseAccess = Kind.isCStyleOrFunctionalCast();
7966 if (S.CheckDerivedToBaseConversion(
7967 SourceType, Step->Type, CurInit.get()->getBeginLoc(),
7968 CurInit.get()->getSourceRange(), &BasePath, IgnoreBaseAccess))
7969 return ExprError();
7970
7971 ExprValueKind VK =
7972 Step->Kind == SK_CastDerivedToBaseLValue ?
7973 VK_LValue :
7974 (Step->Kind == SK_CastDerivedToBaseXValue ?
7975 VK_XValue :
7976 VK_RValue);
7977 CurInit =
7978 ImplicitCastExpr::Create(S.Context, Step->Type, CK_DerivedToBase,
7979 CurInit.get(), &BasePath, VK);
7980 break;
7981 }
7982
7983 case SK_BindReference:
7984 // Reference binding does not have any corresponding ASTs.
7985
7986 // Check exception specifications
7987 if (S.CheckExceptionSpecCompatibility(CurInit.get(), DestType))
7988 return ExprError();
7989
7990 // We don't check for e.g. function pointers here, since address
7991 // availability checks should only occur when the function first decays
7992 // into a pointer or reference.
7993 if (CurInit.get()->getType()->isFunctionProtoType()) {
7994 if (auto *DRE = dyn_cast<DeclRefExpr>(CurInit.get()->IgnoreParens())) {
7995 if (auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl())) {
7996 if (!S.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true,
7997 DRE->getBeginLoc()))
7998 return ExprError();
7999 }
8000 }
8001 }
8002
8003 CheckForNullPointerDereference(S, CurInit.get());
8004 break;
8005
8006 case SK_BindReferenceToTemporary: {
8007 // Make sure the "temporary" is actually an rvalue.
8008 assert(CurInit.get()->isRValue() && "not a temporary");
8009
8010 // Check exception specifications
8011 if (S.CheckExceptionSpecCompatibility(CurInit.get(), DestType))
8012 return ExprError();
8013
8014 // Materialize the temporary into memory.
8015 MaterializeTemporaryExpr *MTE = S.CreateMaterializeTemporaryExpr(
8016 Step->Type, CurInit.get(), Entity.getType()->isLValueReferenceType());
8017 CurInit = MTE;
8018
8019 // If we're extending this temporary to automatic storage duration -- we
8020 // need to register its cleanup during the full-expression's cleanups.
8021 if (MTE->getStorageDuration() == SD_Automatic &&
8022 MTE->getType().isDestructedType())
8023 S.Cleanup.setExprNeedsCleanups(true);
8024 break;
8025 }
8026
8027 case SK_FinalCopy:
8028 if (checkAbstractType(Step->Type))
8029 return ExprError();
8030
8031 // If the overall initialization is initializing a temporary, we already
8032 // bound our argument if it was necessary to do so. If not (if we're
8033 // ultimately initializing a non-temporary), our argument needs to be
8034 // bound since it's initializing a function parameter.
8035 // FIXME: This is a mess. Rationalize temporary destruction.
8036 if (!shouldBindAsTemporary(Entity))
8037 CurInit = S.MaybeBindToTemporary(CurInit.get());
8038 CurInit = CopyObject(S, Step->Type, Entity, CurInit,
8039 /*IsExtraneousCopy=*/false);
8040 break;
8041
8042 case SK_ExtraneousCopyToTemporary:
8043 CurInit = CopyObject(S, Step->Type, Entity, CurInit,
8044 /*IsExtraneousCopy=*/true);
8045 break;
8046
8047 case SK_UserConversion: {
8048 // We have a user-defined conversion that invokes either a constructor
8049 // or a conversion function.
8050 CastKind CastKind;
8051 FunctionDecl *Fn = Step->Function.Function;
8052 DeclAccessPair FoundFn = Step->Function.FoundDecl;
8053 bool HadMultipleCandidates = Step->Function.HadMultipleCandidates;
8054 bool CreatedObject = false;
8055 if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Fn)) {
8056 // Build a call to the selected constructor.
8057 SmallVector<Expr*, 8> ConstructorArgs;
8058 SourceLocation Loc = CurInit.get()->getBeginLoc();
8059
8060 // Determine the arguments required to actually perform the constructor
8061 // call.
8062 Expr *Arg = CurInit.get();
8063 if (S.CompleteConstructorCall(Constructor,
8064 MultiExprArg(&Arg, 1),
8065 Loc, ConstructorArgs))
8066 return ExprError();
8067
8068 // Build an expression that constructs a temporary.
8069 CurInit = S.BuildCXXConstructExpr(Loc, Step->Type,
8070 FoundFn, Constructor,
8071 ConstructorArgs,
8072 HadMultipleCandidates,
8073 /*ListInit*/ false,
8074 /*StdInitListInit*/ false,
8075 /*ZeroInit*/ false,
8076 CXXConstructExpr::CK_Complete,
8077 SourceRange());
8078 if (CurInit.isInvalid())
8079 return ExprError();
8080
8081 S.CheckConstructorAccess(Kind.getLocation(), Constructor, FoundFn,
8082 Entity);
8083 if (S.DiagnoseUseOfDecl(FoundFn, Kind.getLocation()))
8084 return ExprError();
8085
8086 CastKind = CK_ConstructorConversion;
8087 CreatedObject = true;
8088 } else {
8089 // Build a call to the conversion function.
8090 CXXConversionDecl *Conversion = cast<CXXConversionDecl>(Fn);
8091 S.CheckMemberOperatorAccess(Kind.getLocation(), CurInit.get(), nullptr,
8092 FoundFn);
8093 if (S.DiagnoseUseOfDecl(FoundFn, Kind.getLocation()))
8094 return ExprError();
8095
8096 CurInit = S.BuildCXXMemberCallExpr(CurInit.get(), FoundFn, Conversion,
8097 HadMultipleCandidates);
8098 if (CurInit.isInvalid())
8099 return ExprError();
8100
8101 CastKind = CK_UserDefinedConversion;
8102 CreatedObject = Conversion->getReturnType()->isRecordType();
8103 }
8104
8105 if (CreatedObject && checkAbstractType(CurInit.get()->getType()))
8106 return ExprError();
8107
8108 CurInit = ImplicitCastExpr::Create(S.Context, CurInit.get()->getType(),
8109 CastKind, CurInit.get(), nullptr,
8110 CurInit.get()->getValueKind());
8111
8112 if (shouldBindAsTemporary(Entity))
8113 // The overall entity is temporary, so this expression should be
8114 // destroyed at the end of its full-expression.
8115 CurInit = S.MaybeBindToTemporary(CurInit.getAs<Expr>());
8116 else if (CreatedObject && shouldDestroyEntity(Entity)) {
8117 // The object outlasts the full-expression, but we need to prepare for
8118 // a destructor being run on it.
8119 // FIXME: It makes no sense to do this here. This should happen
8120 // regardless of how we initialized the entity.
8121 QualType T = CurInit.get()->getType();
8122 if (const RecordType *Record = T->getAs<RecordType>()) {
8123 CXXDestructorDecl *Destructor
8124 = S.LookupDestructor(cast<CXXRecordDecl>(Record->getDecl()));
8125 S.CheckDestructorAccess(CurInit.get()->getBeginLoc(), Destructor,
8126 S.PDiag(diag::err_access_dtor_temp) << T);
8127 S.MarkFunctionReferenced(CurInit.get()->getBeginLoc(), Destructor);
8128 if (S.DiagnoseUseOfDecl(Destructor, CurInit.get()->getBeginLoc()))
8129 return ExprError();
8130 }
8131 }
8132 break;
8133 }
8134
8135 case SK_QualificationConversionLValue:
8136 case SK_QualificationConversionXValue:
8137 case SK_QualificationConversionRValue: {
8138 // Perform a qualification conversion; these can never go wrong.
8139 ExprValueKind VK =
8140 Step->Kind == SK_QualificationConversionLValue
8141 ? VK_LValue
8142 : (Step->Kind == SK_QualificationConversionXValue ? VK_XValue
8143 : VK_RValue);
8144 CurInit = S.PerformQualificationConversion(CurInit.get(), Step->Type, VK);
8145 break;
8146 }
8147
8148 case SK_AtomicConversion: {
8149 assert(CurInit.get()->isRValue() && "cannot convert glvalue to atomic");
8150 CurInit = S.ImpCastExprToType(CurInit.get(), Step->Type,
8151 CK_NonAtomicToAtomic, VK_RValue);
8152 break;
8153 }
8154
8155 case SK_ConversionSequence:
8156 case SK_ConversionSequenceNoNarrowing: {
8157 if (const auto *FromPtrType =
8158 CurInit.get()->getType()->getAs<PointerType>()) {
8159 if (const auto *ToPtrType = Step->Type->getAs<PointerType>()) {
8160 if (FromPtrType->getPointeeType()->hasAttr(attr::NoDeref) &&
8161 !ToPtrType->getPointeeType()->hasAttr(attr::NoDeref)) {
8162 S.Diag(CurInit.get()->getExprLoc(),
8163 diag::warn_noderef_to_dereferenceable_pointer)
8164 << CurInit.get()->getSourceRange();
8165 }
8166 }
8167 }
8168
8169 Sema::CheckedConversionKind CCK
8170 = Kind.isCStyleCast()? Sema::CCK_CStyleCast
8171 : Kind.isFunctionalCast()? Sema::CCK_FunctionalCast
8172 : Kind.isExplicitCast()? Sema::CCK_OtherCast
8173 : Sema::CCK_ImplicitConversion;
8174 ExprResult CurInitExprRes =
8175 S.PerformImplicitConversion(CurInit.get(), Step->Type, *Step->ICS,
8176 getAssignmentAction(Entity), CCK);
8177 if (CurInitExprRes.isInvalid())
8178 return ExprError();
8179
8180 S.DiscardMisalignedMemberAddress(Step->Type.getTypePtr(), CurInit.get());
8181
8182 CurInit = CurInitExprRes;
8183
8184 if (Step->Kind == SK_ConversionSequenceNoNarrowing &&
8185 S.getLangOpts().CPlusPlus)
8186 DiagnoseNarrowingInInitList(S, *Step->ICS, SourceType, Entity.getType(),
8187 CurInit.get());
8188
8189 break;
8190 }
8191
8192 case SK_ListInitialization: {
8193 if (checkAbstractType(Step->Type))
8194 return ExprError();
8195
8196 InitListExpr *InitList = cast<InitListExpr>(CurInit.get());
8197 // If we're not initializing the top-level entity, we need to create an
8198 // InitializeTemporary entity for our target type.
8199 QualType Ty = Step->Type;
8200 bool IsTemporary = !S.Context.hasSameType(Entity.getType(), Ty);
8201 InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(Ty);
8202 InitializedEntity InitEntity = IsTemporary ? TempEntity : Entity;
8203 InitListChecker PerformInitList(S, InitEntity,
8204 InitList, Ty, /*VerifyOnly=*/false,
8205 /*TreatUnavailableAsInvalid=*/false);
8206 if (PerformInitList.HadError())
8207 return ExprError();
8208
8209 // Hack: We must update *ResultType if available in order to set the
8210 // bounds of arrays, e.g. in 'int ar[] = {1, 2, 3};'.
8211 // Worst case: 'const int (&arref)[] = {1, 2, 3};'.
8212 if (ResultType &&
8213 ResultType->getNonReferenceType()->isIncompleteArrayType()) {
8214 if ((*ResultType)->isRValueReferenceType())
8215 Ty = S.Context.getRValueReferenceType(Ty);
8216 else if ((*ResultType)->isLValueReferenceType())
8217 Ty = S.Context.getLValueReferenceType(Ty,
8218 (*ResultType)->castAs<LValueReferenceType>()->isSpelledAsLValue());
8219 *ResultType = Ty;
8220 }
8221
8222 InitListExpr *StructuredInitList =
8223 PerformInitList.getFullyStructuredList();
8224 CurInit.get();
8225 CurInit = shouldBindAsTemporary(InitEntity)
8226 ? S.MaybeBindToTemporary(StructuredInitList)
8227 : StructuredInitList;
8228 break;
8229 }
8230
8231 case SK_ConstructorInitializationFromList: {
8232 if (checkAbstractType(Step->Type))
8233 return ExprError();
8234
8235 // When an initializer list is passed for a parameter of type "reference
8236 // to object", we don't get an EK_Temporary entity, but instead an
8237 // EK_Parameter entity with reference type.
8238 // FIXME: This is a hack. What we really should do is create a user
8239 // conversion step for this case, but this makes it considerably more
8240 // complicated. For now, this will do.
8241 InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(
8242 Entity.getType().getNonReferenceType());
8243 bool UseTemporary = Entity.getType()->isReferenceType();
8244 assert(Args.size() == 1 && "expected a single argument for list init");
8245 InitListExpr *InitList = cast<InitListExpr>(Args[0]);
8246 S.Diag(InitList->getExprLoc(), diag::warn_cxx98_compat_ctor_list_init)
8247 << InitList->getSourceRange();
8248 MultiExprArg Arg(InitList->getInits(), InitList->getNumInits());
8249 CurInit = PerformConstructorInitialization(S, UseTemporary ? TempEntity :
8250 Entity,
8251 Kind, Arg, *Step,
8252 ConstructorInitRequiresZeroInit,
8253 /*IsListInitialization*/true,
8254 /*IsStdInitListInit*/false,
8255 InitList->getLBraceLoc(),
8256 InitList->getRBraceLoc());
8257 break;
8258 }
8259
8260 case SK_UnwrapInitList:
8261 CurInit = cast<InitListExpr>(CurInit.get())->getInit(0);
8262 break;
8263
8264 case SK_RewrapInitList: {
8265 Expr *E = CurInit.get();
8266 InitListExpr *Syntactic = Step->WrappingSyntacticList;
8267 InitListExpr *ILE = new (S.Context) InitListExpr(S.Context,
8268 Syntactic->getLBraceLoc(), E, Syntactic->getRBraceLoc());
8269 ILE->setSyntacticForm(Syntactic);
8270 ILE->setType(E->getType());
8271 ILE->setValueKind(E->getValueKind());
8272 CurInit = ILE;
8273 break;
8274 }
8275
8276 case SK_ConstructorInitialization:
8277 case SK_StdInitializerListConstructorCall: {
8278 if (checkAbstractType(Step->Type))
8279 return ExprError();
8280
8281 // When an initializer list is passed for a parameter of type "reference
8282 // to object", we don't get an EK_Temporary entity, but instead an
8283 // EK_Parameter entity with reference type.
8284 // FIXME: This is a hack. What we really should do is create a user
8285 // conversion step for this case, but this makes it considerably more
8286 // complicated. For now, this will do.
8287 InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(
8288 Entity.getType().getNonReferenceType());
8289 bool UseTemporary = Entity.getType()->isReferenceType();
8290 bool IsStdInitListInit =
8291 Step->Kind == SK_StdInitializerListConstructorCall;
8292 Expr *Source = CurInit.get();
8293 SourceRange Range = Kind.hasParenOrBraceRange()
8294 ? Kind.getParenOrBraceRange()
8295 : SourceRange();
8296 CurInit = PerformConstructorInitialization(
8297 S, UseTemporary ? TempEntity : Entity, Kind,
8298 Source ? MultiExprArg(Source) : Args, *Step,
8299 ConstructorInitRequiresZeroInit,
8300 /*IsListInitialization*/ IsStdInitListInit,
8301 /*IsStdInitListInitialization*/ IsStdInitListInit,
8302 /*LBraceLoc*/ Range.getBegin(),
8303 /*RBraceLoc*/ Range.getEnd());
8304 break;
8305 }
8306
8307 case SK_ZeroInitialization: {
8308 step_iterator NextStep = Step;
8309 ++NextStep;
8310 if (NextStep != StepEnd &&
8311 (NextStep->Kind == SK_ConstructorInitialization ||
8312 NextStep->Kind == SK_ConstructorInitializationFromList)) {
8313 // The need for zero-initialization is recorded directly into
8314 // the call to the object's constructor within the next step.
8315 ConstructorInitRequiresZeroInit = true;
8316 } else if (Kind.getKind() == InitializationKind::IK_Value &&
8317 S.getLangOpts().CPlusPlus &&
8318 !Kind.isImplicitValueInit()) {
8319 TypeSourceInfo *TSInfo = Entity.getTypeSourceInfo();
8320 if (!TSInfo)
8321 TSInfo = S.Context.getTrivialTypeSourceInfo(Step->Type,
8322 Kind.getRange().getBegin());
8323
8324 CurInit = new (S.Context) CXXScalarValueInitExpr(
8325 Entity.getType().getNonLValueExprType(S.Context), TSInfo,
8326 Kind.getRange().getEnd());
8327 } else {
8328 CurInit = new (S.Context) ImplicitValueInitExpr(Step->Type);
8329 }
8330 break;
8331 }
8332
8333 case SK_CAssignment: {
8334 QualType SourceType = CurInit.get()->getType();
8335
8336 // Save off the initial CurInit in case we need to emit a diagnostic
8337 ExprResult InitialCurInit = CurInit;
8338 ExprResult Result = CurInit;
8339 Sema::AssignConvertType ConvTy =
8340 S.CheckSingleAssignmentConstraints(Step->Type, Result, true,
8341 Entity.getKind() == InitializedEntity::EK_Parameter_CF_Audited);
8342 if (Result.isInvalid())
8343 return ExprError();
8344 CurInit = Result;
8345
8346 // If this is a call, allow conversion to a transparent union.
8347 ExprResult CurInitExprRes = CurInit;
8348 if (ConvTy != Sema::Compatible &&
8349 Entity.isParameterKind() &&
8350 S.CheckTransparentUnionArgumentConstraints(Step->Type, CurInitExprRes)
8351 == Sema::Compatible)
8352 ConvTy = Sema::Compatible;
8353 if (CurInitExprRes.isInvalid())
8354 return ExprError();
8355 CurInit = CurInitExprRes;
8356
8357 bool Complained;
8358 if (S.DiagnoseAssignmentResult(ConvTy, Kind.getLocation(),
8359 Step->Type, SourceType,
8360 InitialCurInit.get(),
8361 getAssignmentAction(Entity, true),
8362 &Complained)) {
8363 PrintInitLocationNote(S, Entity);
8364 return ExprError();
8365 } else if (Complained)
8366 PrintInitLocationNote(S, Entity);
8367 break;
8368 }
8369
8370 case SK_StringInit: {
8371 QualType Ty = Step->Type;
8372 CheckStringInit(CurInit.get(), ResultType ? *ResultType : Ty,
8373 S.Context.getAsArrayType(Ty), S);
8374 break;
8375 }
8376
8377 case SK_ObjCObjectConversion:
8378 CurInit = S.ImpCastExprToType(CurInit.get(), Step->Type,
8379 CK_ObjCObjectLValueCast,
8380 CurInit.get()->getValueKind());
8381 break;
8382
8383 case SK_ArrayLoopIndex: {
8384 Expr *Cur = CurInit.get();
8385 Expr *BaseExpr = new (S.Context)
8386 OpaqueValueExpr(Cur->getExprLoc(), Cur->getType(),
8387 Cur->getValueKind(), Cur->getObjectKind(), Cur);
8388 Expr *IndexExpr =
8389 new (S.Context) ArrayInitIndexExpr(S.Context.getSizeType());
8390 CurInit = S.CreateBuiltinArraySubscriptExpr(
8391 BaseExpr, Kind.getLocation(), IndexExpr, Kind.getLocation());
8392 ArrayLoopCommonExprs.push_back(BaseExpr);
8393 break;
8394 }
8395
8396 case SK_ArrayLoopInit: {
8397 assert(!ArrayLoopCommonExprs.empty() &&
8398 "mismatched SK_ArrayLoopIndex and SK_ArrayLoopInit");
8399 Expr *Common = ArrayLoopCommonExprs.pop_back_val();
8400 CurInit = new (S.Context) ArrayInitLoopExpr(Step->Type, Common,
8401 CurInit.get());
8402 break;
8403 }
8404
8405 case SK_GNUArrayInit:
8406 // Okay: we checked everything before creating this step. Note that
8407 // this is a GNU extension.
8408 S.Diag(Kind.getLocation(), diag::ext_array_init_copy)
8409 << Step->Type << CurInit.get()->getType()
8410 << CurInit.get()->getSourceRange();
8411 updateGNUCompoundLiteralRValue(CurInit.get());
8412 LLVM_FALLTHROUGH;
8413 case SK_ArrayInit:
8414 // If the destination type is an incomplete array type, update the
8415 // type accordingly.
8416 if (ResultType) {
8417 if (const IncompleteArrayType *IncompleteDest
8418 = S.Context.getAsIncompleteArrayType(Step->Type)) {
8419 if (const ConstantArrayType *ConstantSource
8420 = S.Context.getAsConstantArrayType(CurInit.get()->getType())) {
8421 *ResultType = S.Context.getConstantArrayType(
8422 IncompleteDest->getElementType(),
8423 ConstantSource->getSize(),
8424 ConstantSource->getSizeExpr(),
8425 ArrayType::Normal, 0);
8426 }
8427 }
8428 }
8429 break;
8430
8431 case SK_ParenthesizedArrayInit:
8432 // Okay: we checked everything before creating this step. Note that
8433 // this is a GNU extension.
8434 S.Diag(Kind.getLocation(), diag::ext_array_init_parens)
8435 << CurInit.get()->getSourceRange();
8436 break;
8437
8438 case SK_PassByIndirectCopyRestore:
8439 case SK_PassByIndirectRestore:
8440 checkIndirectCopyRestoreSource(S, CurInit.get());
8441 CurInit = new (S.Context) ObjCIndirectCopyRestoreExpr(
8442 CurInit.get(), Step->Type,
8443 Step->Kind == SK_PassByIndirectCopyRestore);
8444 break;
8445
8446 case SK_ProduceObjCObject:
8447 CurInit =
8448 ImplicitCastExpr::Create(S.Context, Step->Type, CK_ARCProduceObject,
8449 CurInit.get(), nullptr, VK_RValue);
8450 break;
8451
8452 case SK_StdInitializerList: {
8453 S.Diag(CurInit.get()->getExprLoc(),
8454 diag::warn_cxx98_compat_initializer_list_init)
8455 << CurInit.get()->getSourceRange();
8456
8457 // Materialize the temporary into memory.
8458 MaterializeTemporaryExpr *MTE = S.CreateMaterializeTemporaryExpr(
8459 CurInit.get()->getType(), CurInit.get(),
8460 /*BoundToLvalueReference=*/false);
8461
8462 // Wrap it in a construction of a std::initializer_list<T>.
8463 CurInit = new (S.Context) CXXStdInitializerListExpr(Step->Type, MTE);
8464
8465 // Bind the result, in case the library has given initializer_list a
8466 // non-trivial destructor.
8467 if (shouldBindAsTemporary(Entity))
8468 CurInit = S.MaybeBindToTemporary(CurInit.get());
8469 break;
8470 }
8471
8472 case SK_OCLSamplerInit: {
8473 // Sampler initialization have 5 cases:
8474 // 1. function argument passing
8475 // 1a. argument is a file-scope variable
8476 // 1b. argument is a function-scope variable
8477 // 1c. argument is one of caller function's parameters
8478 // 2. variable initialization
8479 // 2a. initializing a file-scope variable
8480 // 2b. initializing a function-scope variable
8481 //
8482 // For file-scope variables, since they cannot be initialized by function
8483 // call of __translate_sampler_initializer in LLVM IR, their references
8484 // need to be replaced by a cast from their literal initializers to
8485 // sampler type. Since sampler variables can only be used in function
8486 // calls as arguments, we only need to replace them when handling the
8487 // argument passing.
8488 assert(Step->Type->isSamplerT() &&
8489 "Sampler initialization on non-sampler type.");
8490 Expr *Init = CurInit.get()->IgnoreParens();
8491 QualType SourceType = Init->getType();
8492 // Case 1
8493 if (Entity.isParameterKind()) {
8494 if (!SourceType->isSamplerT() && !SourceType->isIntegerType()) {
8495 S.Diag(Kind.getLocation(), diag::err_sampler_argument_required)
8496 << SourceType;
8497 break;
8498 } else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Init)) {
8499 auto Var = cast<VarDecl>(DRE->getDecl());
8500 // Case 1b and 1c
8501 // No cast from integer to sampler is needed.
8502 if (!Var->hasGlobalStorage()) {
8503 CurInit = ImplicitCastExpr::Create(S.Context, Step->Type,
8504 CK_LValueToRValue, Init,
8505 /*BasePath=*/nullptr, VK_RValue);
8506 break;
8507 }
8508 // Case 1a
8509 // For function call with a file-scope sampler variable as argument,
8510 // get the integer literal.
8511 // Do not diagnose if the file-scope variable does not have initializer
8512 // since this has already been diagnosed when parsing the variable
8513 // declaration.
8514 if (!Var->getInit() || !isa<ImplicitCastExpr>(Var->getInit()))
8515 break;
8516 Init = cast<ImplicitCastExpr>(const_cast<Expr*>(
8517 Var->getInit()))->getSubExpr();
8518 SourceType = Init->getType();
8519 }
8520 } else {
8521 // Case 2
8522 // Check initializer is 32 bit integer constant.
8523 // If the initializer is taken from global variable, do not diagnose since
8524 // this has already been done when parsing the variable declaration.
8525 if (!Init->isConstantInitializer(S.Context, false))
8526 break;
8527
8528 if (!SourceType->isIntegerType() ||
8529 32 != S.Context.getIntWidth(SourceType)) {
8530 S.Diag(Kind.getLocation(), diag::err_sampler_initializer_not_integer)
8531 << SourceType;
8532 break;
8533 }
8534
8535 Expr::EvalResult EVResult;
8536 Init->EvaluateAsInt(EVResult, S.Context);
8537 llvm::APSInt Result = EVResult.Val.getInt();
8538 const uint64_t SamplerValue = Result.getLimitedValue();
8539 // 32-bit value of sampler's initializer is interpreted as
8540 // bit-field with the following structure:
8541 // |unspecified|Filter|Addressing Mode| Normalized Coords|
8542 // |31 6|5 4|3 1| 0|
8543 // This structure corresponds to enum values of sampler properties
8544 // defined in SPIR spec v1.2 and also opencl-c.h
8545 unsigned AddressingMode = (0x0E & SamplerValue) >> 1;
8546 unsigned FilterMode = (0x30 & SamplerValue) >> 4;
8547 if (FilterMode != 1 && FilterMode != 2 &&
8548 !S.getOpenCLOptions().isEnabled(
8549 "cl_intel_device_side_avc_motion_estimation"))
8550 S.Diag(Kind.getLocation(),
8551 diag::warn_sampler_initializer_invalid_bits)
8552 << "Filter Mode";
8553 if (AddressingMode > 4)
8554 S.Diag(Kind.getLocation(),
8555 diag::warn_sampler_initializer_invalid_bits)
8556 << "Addressing Mode";
8557 }
8558
8559 // Cases 1a, 2a and 2b
8560 // Insert cast from integer to sampler.
8561 CurInit = S.ImpCastExprToType(Init, S.Context.OCLSamplerTy,
8562 CK_IntToOCLSampler);
8563 break;
8564 }
8565 case SK_OCLZeroOpaqueType: {
8566 assert((Step->Type->isEventT() || Step->Type->isQueueT() ||
8567 Step->Type->isOCLIntelSubgroupAVCType()) &&
8568 "Wrong type for initialization of OpenCL opaque type.");
8569
8570 CurInit = S.ImpCastExprToType(CurInit.get(), Step->Type,
8571 CK_ZeroToOCLOpaqueType,
8572 CurInit.get()->getValueKind());
8573 break;
8574 }
8575 }
8576 }
8577
8578 // Check whether the initializer has a shorter lifetime than the initialized
8579 // entity, and if not, either lifetime-extend or warn as appropriate.
8580 if (auto *Init = CurInit.get())
8581 S.checkInitializerLifetime(Entity, Init);
8582
8583 // Diagnose non-fatal problems with the completed initialization.
8584 if (Entity.getKind() == InitializedEntity::EK_Member &&
8585 cast<FieldDecl>(Entity.getDecl())->isBitField())
8586 S.CheckBitFieldInitialization(Kind.getLocation(),
8587 cast<FieldDecl>(Entity.getDecl()),
8588 CurInit.get());
8589
8590 // Check for std::move on construction.
8591 if (const Expr *E = CurInit.get()) {
8592 CheckMoveOnConstruction(S, E,
8593 Entity.getKind() == InitializedEntity::EK_Result);
8594 }
8595
8596 return CurInit;
8597 }
8598
8599 /// Somewhere within T there is an uninitialized reference subobject.
8600 /// Dig it out and diagnose it.
DiagnoseUninitializedReference(Sema & S,SourceLocation Loc,QualType T)8601 static bool DiagnoseUninitializedReference(Sema &S, SourceLocation Loc,
8602 QualType T) {
8603 if (T->isReferenceType()) {
8604 S.Diag(Loc, diag::err_reference_without_init)
8605 << T.getNonReferenceType();
8606 return true;
8607 }
8608
8609 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
8610 if (!RD || !RD->hasUninitializedReferenceMember())
8611 return false;
8612
8613 for (const auto *FI : RD->fields()) {
8614 if (FI->isUnnamedBitfield())
8615 continue;
8616
8617 if (DiagnoseUninitializedReference(S, FI->getLocation(), FI->getType())) {
8618 S.Diag(Loc, diag::note_value_initialization_here) << RD;
8619 return true;
8620 }
8621 }
8622
8623 for (const auto &BI : RD->bases()) {
8624 if (DiagnoseUninitializedReference(S, BI.getBeginLoc(), BI.getType())) {
8625 S.Diag(Loc, diag::note_value_initialization_here) << RD;
8626 return true;
8627 }
8628 }
8629
8630 return false;
8631 }
8632
8633
8634 //===----------------------------------------------------------------------===//
8635 // Diagnose initialization failures
8636 //===----------------------------------------------------------------------===//
8637
8638 /// Emit notes associated with an initialization that failed due to a
8639 /// "simple" conversion failure.
emitBadConversionNotes(Sema & S,const InitializedEntity & entity,Expr * op)8640 static void emitBadConversionNotes(Sema &S, const InitializedEntity &entity,
8641 Expr *op) {
8642 QualType destType = entity.getType();
8643 if (destType.getNonReferenceType()->isObjCObjectPointerType() &&
8644 op->getType()->isObjCObjectPointerType()) {
8645
8646 // Emit a possible note about the conversion failing because the
8647 // operand is a message send with a related result type.
8648 S.EmitRelatedResultTypeNote(op);
8649
8650 // Emit a possible note about a return failing because we're
8651 // expecting a related result type.
8652 if (entity.getKind() == InitializedEntity::EK_Result)
8653 S.EmitRelatedResultTypeNoteForReturn(destType);
8654 }
8655 }
8656
diagnoseListInit(Sema & S,const InitializedEntity & Entity,InitListExpr * InitList)8657 static void diagnoseListInit(Sema &S, const InitializedEntity &Entity,
8658 InitListExpr *InitList) {
8659 QualType DestType = Entity.getType();
8660
8661 QualType E;
8662 if (S.getLangOpts().CPlusPlus11 && S.isStdInitializerList(DestType, &E)) {
8663 QualType ArrayType = S.Context.getConstantArrayType(
8664 E.withConst(),
8665 llvm::APInt(S.Context.getTypeSize(S.Context.getSizeType()),
8666 InitList->getNumInits()),
8667 nullptr, clang::ArrayType::Normal, 0);
8668 InitializedEntity HiddenArray =
8669 InitializedEntity::InitializeTemporary(ArrayType);
8670 return diagnoseListInit(S, HiddenArray, InitList);
8671 }
8672
8673 if (DestType->isReferenceType()) {
8674 // A list-initialization failure for a reference means that we tried to
8675 // create a temporary of the inner type (per [dcl.init.list]p3.6) and the
8676 // inner initialization failed.
8677 QualType T = DestType->castAs<ReferenceType>()->getPointeeType();
8678 diagnoseListInit(S, InitializedEntity::InitializeTemporary(T), InitList);
8679 SourceLocation Loc = InitList->getBeginLoc();
8680 if (auto *D = Entity.getDecl())
8681 Loc = D->getLocation();
8682 S.Diag(Loc, diag::note_in_reference_temporary_list_initializer) << T;
8683 return;
8684 }
8685
8686 InitListChecker DiagnoseInitList(S, Entity, InitList, DestType,
8687 /*VerifyOnly=*/false,
8688 /*TreatUnavailableAsInvalid=*/false);
8689 assert(DiagnoseInitList.HadError() &&
8690 "Inconsistent init list check result.");
8691 }
8692
Diagnose(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,ArrayRef<Expr * > Args)8693 bool InitializationSequence::Diagnose(Sema &S,
8694 const InitializedEntity &Entity,
8695 const InitializationKind &Kind,
8696 ArrayRef<Expr *> Args) {
8697 if (!Failed())
8698 return false;
8699
8700 // When we want to diagnose only one element of a braced-init-list,
8701 // we need to factor it out.
8702 Expr *OnlyArg;
8703 if (Args.size() == 1) {
8704 auto *List = dyn_cast<InitListExpr>(Args[0]);
8705 if (List && List->getNumInits() == 1)
8706 OnlyArg = List->getInit(0);
8707 else
8708 OnlyArg = Args[0];
8709 }
8710 else
8711 OnlyArg = nullptr;
8712
8713 QualType DestType = Entity.getType();
8714 switch (Failure) {
8715 case FK_TooManyInitsForReference:
8716 // FIXME: Customize for the initialized entity?
8717 if (Args.empty()) {
8718 // Dig out the reference subobject which is uninitialized and diagnose it.
8719 // If this is value-initialization, this could be nested some way within
8720 // the target type.
8721 assert(Kind.getKind() == InitializationKind::IK_Value ||
8722 DestType->isReferenceType());
8723 bool Diagnosed =
8724 DiagnoseUninitializedReference(S, Kind.getLocation(), DestType);
8725 assert(Diagnosed && "couldn't find uninitialized reference to diagnose");
8726 (void)Diagnosed;
8727 } else // FIXME: diagnostic below could be better!
8728 S.Diag(Kind.getLocation(), diag::err_reference_has_multiple_inits)
8729 << SourceRange(Args.front()->getBeginLoc(), Args.back()->getEndLoc());
8730 break;
8731 case FK_ParenthesizedListInitForReference:
8732 S.Diag(Kind.getLocation(), diag::err_list_init_in_parens)
8733 << 1 << Entity.getType() << Args[0]->getSourceRange();
8734 break;
8735
8736 case FK_ArrayNeedsInitList:
8737 S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 0;
8738 break;
8739 case FK_ArrayNeedsInitListOrStringLiteral:
8740 S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 1;
8741 break;
8742 case FK_ArrayNeedsInitListOrWideStringLiteral:
8743 S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 2;
8744 break;
8745 case FK_NarrowStringIntoWideCharArray:
8746 S.Diag(Kind.getLocation(), diag::err_array_init_narrow_string_into_wchar);
8747 break;
8748 case FK_WideStringIntoCharArray:
8749 S.Diag(Kind.getLocation(), diag::err_array_init_wide_string_into_char);
8750 break;
8751 case FK_IncompatWideStringIntoWideChar:
8752 S.Diag(Kind.getLocation(),
8753 diag::err_array_init_incompat_wide_string_into_wchar);
8754 break;
8755 case FK_PlainStringIntoUTF8Char:
8756 S.Diag(Kind.getLocation(),
8757 diag::err_array_init_plain_string_into_char8_t);
8758 S.Diag(Args.front()->getBeginLoc(),
8759 diag::note_array_init_plain_string_into_char8_t)
8760 << FixItHint::CreateInsertion(Args.front()->getBeginLoc(), "u8");
8761 break;
8762 case FK_UTF8StringIntoPlainChar:
8763 S.Diag(Kind.getLocation(),
8764 diag::err_array_init_utf8_string_into_char)
8765 << S.getLangOpts().CPlusPlus2a;
8766 break;
8767 case FK_ArrayTypeMismatch:
8768 case FK_NonConstantArrayInit:
8769 S.Diag(Kind.getLocation(),
8770 (Failure == FK_ArrayTypeMismatch
8771 ? diag::err_array_init_different_type
8772 : diag::err_array_init_non_constant_array))
8773 << DestType.getNonReferenceType()
8774 << OnlyArg->getType()
8775 << Args[0]->getSourceRange();
8776 break;
8777
8778 case FK_VariableLengthArrayHasInitializer:
8779 S.Diag(Kind.getLocation(), diag::err_variable_object_no_init)
8780 << Args[0]->getSourceRange();
8781 break;
8782
8783 case FK_AddressOfOverloadFailed: {
8784 DeclAccessPair Found;
8785 S.ResolveAddressOfOverloadedFunction(OnlyArg,
8786 DestType.getNonReferenceType(),
8787 true,
8788 Found);
8789 break;
8790 }
8791
8792 case FK_AddressOfUnaddressableFunction: {
8793 auto *FD = cast<FunctionDecl>(cast<DeclRefExpr>(OnlyArg)->getDecl());
8794 S.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true,
8795 OnlyArg->getBeginLoc());
8796 break;
8797 }
8798
8799 case FK_ReferenceInitOverloadFailed:
8800 case FK_UserConversionOverloadFailed:
8801 switch (FailedOverloadResult) {
8802 case OR_Ambiguous:
8803
8804 FailedCandidateSet.NoteCandidates(
8805 PartialDiagnosticAt(
8806 Kind.getLocation(),
8807 Failure == FK_UserConversionOverloadFailed
8808 ? (S.PDiag(diag::err_typecheck_ambiguous_condition)
8809 << OnlyArg->getType() << DestType
8810 << Args[0]->getSourceRange())
8811 : (S.PDiag(diag::err_ref_init_ambiguous)
8812 << DestType << OnlyArg->getType()
8813 << Args[0]->getSourceRange())),
8814 S, OCD_AmbiguousCandidates, Args);
8815 break;
8816
8817 case OR_No_Viable_Function: {
8818 auto Cands = FailedCandidateSet.CompleteCandidates(S, OCD_AllCandidates, Args);
8819 if (!S.RequireCompleteType(Kind.getLocation(),
8820 DestType.getNonReferenceType(),
8821 diag::err_typecheck_nonviable_condition_incomplete,
8822 OnlyArg->getType(), Args[0]->getSourceRange()))
8823 S.Diag(Kind.getLocation(), diag::err_typecheck_nonviable_condition)
8824 << (Entity.getKind() == InitializedEntity::EK_Result)
8825 << OnlyArg->getType() << Args[0]->getSourceRange()
8826 << DestType.getNonReferenceType();
8827
8828 FailedCandidateSet.NoteCandidates(S, Args, Cands);
8829 break;
8830 }
8831 case OR_Deleted: {
8832 S.Diag(Kind.getLocation(), diag::err_typecheck_deleted_function)
8833 << OnlyArg->getType() << DestType.getNonReferenceType()
8834 << Args[0]->getSourceRange();
8835 OverloadCandidateSet::iterator Best;
8836 OverloadingResult Ovl
8837 = FailedCandidateSet.BestViableFunction(S, Kind.getLocation(), Best);
8838 if (Ovl == OR_Deleted) {
8839 S.NoteDeletedFunction(Best->Function);
8840 } else {
8841 llvm_unreachable("Inconsistent overload resolution?");
8842 }
8843 break;
8844 }
8845
8846 case OR_Success:
8847 llvm_unreachable("Conversion did not fail!");
8848 }
8849 break;
8850
8851 case FK_NonConstLValueReferenceBindingToTemporary:
8852 if (isa<InitListExpr>(Args[0])) {
8853 S.Diag(Kind.getLocation(),
8854 diag::err_lvalue_reference_bind_to_initlist)
8855 << DestType.getNonReferenceType().isVolatileQualified()
8856 << DestType.getNonReferenceType()
8857 << Args[0]->getSourceRange();
8858 break;
8859 }
8860 LLVM_FALLTHROUGH;
8861
8862 case FK_NonConstLValueReferenceBindingToUnrelated:
8863 S.Diag(Kind.getLocation(),
8864 Failure == FK_NonConstLValueReferenceBindingToTemporary
8865 ? diag::err_lvalue_reference_bind_to_temporary
8866 : diag::err_lvalue_reference_bind_to_unrelated)
8867 << DestType.getNonReferenceType().isVolatileQualified()
8868 << DestType.getNonReferenceType()
8869 << OnlyArg->getType()
8870 << Args[0]->getSourceRange();
8871 break;
8872
8873 case FK_NonConstLValueReferenceBindingToBitfield: {
8874 // We don't necessarily have an unambiguous source bit-field.
8875 FieldDecl *BitField = Args[0]->getSourceBitField();
8876 S.Diag(Kind.getLocation(), diag::err_reference_bind_to_bitfield)
8877 << DestType.isVolatileQualified()
8878 << (BitField ? BitField->getDeclName() : DeclarationName())
8879 << (BitField != nullptr)
8880 << Args[0]->getSourceRange();
8881 if (BitField)
8882 S.Diag(BitField->getLocation(), diag::note_bitfield_decl);
8883 break;
8884 }
8885
8886 case FK_NonConstLValueReferenceBindingToVectorElement:
8887 S.Diag(Kind.getLocation(), diag::err_reference_bind_to_vector_element)
8888 << DestType.isVolatileQualified()
8889 << Args[0]->getSourceRange();
8890 break;
8891
8892 case FK_RValueReferenceBindingToLValue:
8893 S.Diag(Kind.getLocation(), diag::err_lvalue_to_rvalue_ref)
8894 << DestType.getNonReferenceType() << OnlyArg->getType()
8895 << Args[0]->getSourceRange();
8896 break;
8897
8898 case FK_ReferenceAddrspaceMismatchTemporary:
8899 S.Diag(Kind.getLocation(), diag::err_reference_bind_temporary_addrspace)
8900 << DestType << Args[0]->getSourceRange();
8901 break;
8902
8903 case FK_ReferenceInitDropsQualifiers: {
8904 QualType SourceType = OnlyArg->getType();
8905 QualType NonRefType = DestType.getNonReferenceType();
8906 Qualifiers DroppedQualifiers =
8907 SourceType.getQualifiers() - NonRefType.getQualifiers();
8908
8909 if (!NonRefType.getQualifiers().isAddressSpaceSupersetOf(
8910 SourceType.getQualifiers()))
8911 S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
8912 << NonRefType << SourceType << 1 /*addr space*/
8913 << Args[0]->getSourceRange();
8914 else if (DroppedQualifiers.hasQualifiers())
8915 S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
8916 << NonRefType << SourceType << 0 /*cv quals*/
8917 << Qualifiers::fromCVRMask(DroppedQualifiers.getCVRQualifiers())
8918 << DroppedQualifiers.getCVRQualifiers() << Args[0]->getSourceRange();
8919 else
8920 // FIXME: Consider decomposing the type and explaining which qualifiers
8921 // were dropped where, or on which level a 'const' is missing, etc.
8922 S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
8923 << NonRefType << SourceType << 2 /*incompatible quals*/
8924 << Args[0]->getSourceRange();
8925 break;
8926 }
8927
8928 case FK_ReferenceInitFailed:
8929 S.Diag(Kind.getLocation(), diag::err_reference_bind_failed)
8930 << DestType.getNonReferenceType()
8931 << DestType.getNonReferenceType()->isIncompleteType()
8932 << OnlyArg->isLValue()
8933 << OnlyArg->getType()
8934 << Args[0]->getSourceRange();
8935 emitBadConversionNotes(S, Entity, Args[0]);
8936 break;
8937
8938 case FK_ConversionFailed: {
8939 QualType FromType = OnlyArg->getType();
8940 PartialDiagnostic PDiag = S.PDiag(diag::err_init_conversion_failed)
8941 << (int)Entity.getKind()
8942 << DestType
8943 << OnlyArg->isLValue()
8944 << FromType
8945 << Args[0]->getSourceRange();
8946 S.HandleFunctionTypeMismatch(PDiag, FromType, DestType);
8947 S.Diag(Kind.getLocation(), PDiag);
8948 emitBadConversionNotes(S, Entity, Args[0]);
8949 break;
8950 }
8951
8952 case FK_ConversionFromPropertyFailed:
8953 // No-op. This error has already been reported.
8954 break;
8955
8956 case FK_TooManyInitsForScalar: {
8957 SourceRange R;
8958
8959 auto *InitList = dyn_cast<InitListExpr>(Args[0]);
8960 if (InitList && InitList->getNumInits() >= 1) {
8961 R = SourceRange(InitList->getInit(0)->getEndLoc(), InitList->getEndLoc());
8962 } else {
8963 assert(Args.size() > 1 && "Expected multiple initializers!");
8964 R = SourceRange(Args.front()->getEndLoc(), Args.back()->getEndLoc());
8965 }
8966
8967 R.setBegin(S.getLocForEndOfToken(R.getBegin()));
8968 if (Kind.isCStyleOrFunctionalCast())
8969 S.Diag(Kind.getLocation(), diag::err_builtin_func_cast_more_than_one_arg)
8970 << R;
8971 else
8972 S.Diag(Kind.getLocation(), diag::err_excess_initializers)
8973 << /*scalar=*/2 << R;
8974 break;
8975 }
8976
8977 case FK_ParenthesizedListInitForScalar:
8978 S.Diag(Kind.getLocation(), diag::err_list_init_in_parens)
8979 << 0 << Entity.getType() << Args[0]->getSourceRange();
8980 break;
8981
8982 case FK_ReferenceBindingToInitList:
8983 S.Diag(Kind.getLocation(), diag::err_reference_bind_init_list)
8984 << DestType.getNonReferenceType() << Args[0]->getSourceRange();
8985 break;
8986
8987 case FK_InitListBadDestinationType:
8988 S.Diag(Kind.getLocation(), diag::err_init_list_bad_dest_type)
8989 << (DestType->isRecordType()) << DestType << Args[0]->getSourceRange();
8990 break;
8991
8992 case FK_ListConstructorOverloadFailed:
8993 case FK_ConstructorOverloadFailed: {
8994 SourceRange ArgsRange;
8995 if (Args.size())
8996 ArgsRange =
8997 SourceRange(Args.front()->getBeginLoc(), Args.back()->getEndLoc());
8998
8999 if (Failure == FK_ListConstructorOverloadFailed) {
9000 assert(Args.size() == 1 &&
9001 "List construction from other than 1 argument.");
9002 InitListExpr *InitList = cast<InitListExpr>(Args[0]);
9003 Args = MultiExprArg(InitList->getInits(), InitList->getNumInits());
9004 }
9005
9006 // FIXME: Using "DestType" for the entity we're printing is probably
9007 // bad.
9008 switch (FailedOverloadResult) {
9009 case OR_Ambiguous:
9010 FailedCandidateSet.NoteCandidates(
9011 PartialDiagnosticAt(Kind.getLocation(),
9012 S.PDiag(diag::err_ovl_ambiguous_init)
9013 << DestType << ArgsRange),
9014 S, OCD_AmbiguousCandidates, Args);
9015 break;
9016
9017 case OR_No_Viable_Function:
9018 if (Kind.getKind() == InitializationKind::IK_Default &&
9019 (Entity.getKind() == InitializedEntity::EK_Base ||
9020 Entity.getKind() == InitializedEntity::EK_Member) &&
9021 isa<CXXConstructorDecl>(S.CurContext)) {
9022 // This is implicit default initialization of a member or
9023 // base within a constructor. If no viable function was
9024 // found, notify the user that they need to explicitly
9025 // initialize this base/member.
9026 CXXConstructorDecl *Constructor
9027 = cast<CXXConstructorDecl>(S.CurContext);
9028 const CXXRecordDecl *InheritedFrom = nullptr;
9029 if (auto Inherited = Constructor->getInheritedConstructor())
9030 InheritedFrom = Inherited.getShadowDecl()->getNominatedBaseClass();
9031 if (Entity.getKind() == InitializedEntity::EK_Base) {
9032 S.Diag(Kind.getLocation(), diag::err_missing_default_ctor)
9033 << (InheritedFrom ? 2 : Constructor->isImplicit() ? 1 : 0)
9034 << S.Context.getTypeDeclType(Constructor->getParent())
9035 << /*base=*/0
9036 << Entity.getType()
9037 << InheritedFrom;
9038
9039 RecordDecl *BaseDecl
9040 = Entity.getBaseSpecifier()->getType()->castAs<RecordType>()
9041 ->getDecl();
9042 S.Diag(BaseDecl->getLocation(), diag::note_previous_decl)
9043 << S.Context.getTagDeclType(BaseDecl);
9044 } else {
9045 S.Diag(Kind.getLocation(), diag::err_missing_default_ctor)
9046 << (InheritedFrom ? 2 : Constructor->isImplicit() ? 1 : 0)
9047 << S.Context.getTypeDeclType(Constructor->getParent())
9048 << /*member=*/1
9049 << Entity.getName()
9050 << InheritedFrom;
9051 S.Diag(Entity.getDecl()->getLocation(),
9052 diag::note_member_declared_at);
9053
9054 if (const RecordType *Record
9055 = Entity.getType()->getAs<RecordType>())
9056 S.Diag(Record->getDecl()->getLocation(),
9057 diag::note_previous_decl)
9058 << S.Context.getTagDeclType(Record->getDecl());
9059 }
9060 break;
9061 }
9062
9063 FailedCandidateSet.NoteCandidates(
9064 PartialDiagnosticAt(
9065 Kind.getLocation(),
9066 S.PDiag(diag::err_ovl_no_viable_function_in_init)
9067 << DestType << ArgsRange),
9068 S, OCD_AllCandidates, Args);
9069 break;
9070
9071 case OR_Deleted: {
9072 OverloadCandidateSet::iterator Best;
9073 OverloadingResult Ovl
9074 = FailedCandidateSet.BestViableFunction(S, Kind.getLocation(), Best);
9075 if (Ovl != OR_Deleted) {
9076 S.Diag(Kind.getLocation(), diag::err_ovl_deleted_init)
9077 << DestType << ArgsRange;
9078 llvm_unreachable("Inconsistent overload resolution?");
9079 break;
9080 }
9081
9082 // If this is a defaulted or implicitly-declared function, then
9083 // it was implicitly deleted. Make it clear that the deletion was
9084 // implicit.
9085 if (S.isImplicitlyDeleted(Best->Function))
9086 S.Diag(Kind.getLocation(), diag::err_ovl_deleted_special_init)
9087 << S.getSpecialMember(cast<CXXMethodDecl>(Best->Function))
9088 << DestType << ArgsRange;
9089 else
9090 S.Diag(Kind.getLocation(), diag::err_ovl_deleted_init)
9091 << DestType << ArgsRange;
9092
9093 S.NoteDeletedFunction(Best->Function);
9094 break;
9095 }
9096
9097 case OR_Success:
9098 llvm_unreachable("Conversion did not fail!");
9099 }
9100 }
9101 break;
9102
9103 case FK_DefaultInitOfConst:
9104 if (Entity.getKind() == InitializedEntity::EK_Member &&
9105 isa<CXXConstructorDecl>(S.CurContext)) {
9106 // This is implicit default-initialization of a const member in
9107 // a constructor. Complain that it needs to be explicitly
9108 // initialized.
9109 CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(S.CurContext);
9110 S.Diag(Kind.getLocation(), diag::err_uninitialized_member_in_ctor)
9111 << (Constructor->getInheritedConstructor() ? 2 :
9112 Constructor->isImplicit() ? 1 : 0)
9113 << S.Context.getTypeDeclType(Constructor->getParent())
9114 << /*const=*/1
9115 << Entity.getName();
9116 S.Diag(Entity.getDecl()->getLocation(), diag::note_previous_decl)
9117 << Entity.getName();
9118 } else {
9119 S.Diag(Kind.getLocation(), diag::err_default_init_const)
9120 << DestType << (bool)DestType->getAs<RecordType>();
9121 }
9122 break;
9123
9124 case FK_Incomplete:
9125 S.RequireCompleteType(Kind.getLocation(), FailedIncompleteType,
9126 diag::err_init_incomplete_type);
9127 break;
9128
9129 case FK_ListInitializationFailed: {
9130 // Run the init list checker again to emit diagnostics.
9131 InitListExpr *InitList = cast<InitListExpr>(Args[0]);
9132 diagnoseListInit(S, Entity, InitList);
9133 break;
9134 }
9135
9136 case FK_PlaceholderType: {
9137 // FIXME: Already diagnosed!
9138 break;
9139 }
9140
9141 case FK_ExplicitConstructor: {
9142 S.Diag(Kind.getLocation(), diag::err_selected_explicit_constructor)
9143 << Args[0]->getSourceRange();
9144 OverloadCandidateSet::iterator Best;
9145 OverloadingResult Ovl
9146 = FailedCandidateSet.BestViableFunction(S, Kind.getLocation(), Best);
9147 (void)Ovl;
9148 assert(Ovl == OR_Success && "Inconsistent overload resolution");
9149 CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
9150 S.Diag(CtorDecl->getLocation(),
9151 diag::note_explicit_ctor_deduction_guide_here) << false;
9152 break;
9153 }
9154 }
9155
9156 PrintInitLocationNote(S, Entity);
9157 return true;
9158 }
9159
dump(raw_ostream & OS) const9160 void InitializationSequence::dump(raw_ostream &OS) const {
9161 switch (SequenceKind) {
9162 case FailedSequence: {
9163 OS << "Failed sequence: ";
9164 switch (Failure) {
9165 case FK_TooManyInitsForReference:
9166 OS << "too many initializers for reference";
9167 break;
9168
9169 case FK_ParenthesizedListInitForReference:
9170 OS << "parenthesized list init for reference";
9171 break;
9172
9173 case FK_ArrayNeedsInitList:
9174 OS << "array requires initializer list";
9175 break;
9176
9177 case FK_AddressOfUnaddressableFunction:
9178 OS << "address of unaddressable function was taken";
9179 break;
9180
9181 case FK_ArrayNeedsInitListOrStringLiteral:
9182 OS << "array requires initializer list or string literal";
9183 break;
9184
9185 case FK_ArrayNeedsInitListOrWideStringLiteral:
9186 OS << "array requires initializer list or wide string literal";
9187 break;
9188
9189 case FK_NarrowStringIntoWideCharArray:
9190 OS << "narrow string into wide char array";
9191 break;
9192
9193 case FK_WideStringIntoCharArray:
9194 OS << "wide string into char array";
9195 break;
9196
9197 case FK_IncompatWideStringIntoWideChar:
9198 OS << "incompatible wide string into wide char array";
9199 break;
9200
9201 case FK_PlainStringIntoUTF8Char:
9202 OS << "plain string literal into char8_t array";
9203 break;
9204
9205 case FK_UTF8StringIntoPlainChar:
9206 OS << "u8 string literal into char array";
9207 break;
9208
9209 case FK_ArrayTypeMismatch:
9210 OS << "array type mismatch";
9211 break;
9212
9213 case FK_NonConstantArrayInit:
9214 OS << "non-constant array initializer";
9215 break;
9216
9217 case FK_AddressOfOverloadFailed:
9218 OS << "address of overloaded function failed";
9219 break;
9220
9221 case FK_ReferenceInitOverloadFailed:
9222 OS << "overload resolution for reference initialization failed";
9223 break;
9224
9225 case FK_NonConstLValueReferenceBindingToTemporary:
9226 OS << "non-const lvalue reference bound to temporary";
9227 break;
9228
9229 case FK_NonConstLValueReferenceBindingToBitfield:
9230 OS << "non-const lvalue reference bound to bit-field";
9231 break;
9232
9233 case FK_NonConstLValueReferenceBindingToVectorElement:
9234 OS << "non-const lvalue reference bound to vector element";
9235 break;
9236
9237 case FK_NonConstLValueReferenceBindingToUnrelated:
9238 OS << "non-const lvalue reference bound to unrelated type";
9239 break;
9240
9241 case FK_RValueReferenceBindingToLValue:
9242 OS << "rvalue reference bound to an lvalue";
9243 break;
9244
9245 case FK_ReferenceInitDropsQualifiers:
9246 OS << "reference initialization drops qualifiers";
9247 break;
9248
9249 case FK_ReferenceAddrspaceMismatchTemporary:
9250 OS << "reference with mismatching address space bound to temporary";
9251 break;
9252
9253 case FK_ReferenceInitFailed:
9254 OS << "reference initialization failed";
9255 break;
9256
9257 case FK_ConversionFailed:
9258 OS << "conversion failed";
9259 break;
9260
9261 case FK_ConversionFromPropertyFailed:
9262 OS << "conversion from property failed";
9263 break;
9264
9265 case FK_TooManyInitsForScalar:
9266 OS << "too many initializers for scalar";
9267 break;
9268
9269 case FK_ParenthesizedListInitForScalar:
9270 OS << "parenthesized list init for reference";
9271 break;
9272
9273 case FK_ReferenceBindingToInitList:
9274 OS << "referencing binding to initializer list";
9275 break;
9276
9277 case FK_InitListBadDestinationType:
9278 OS << "initializer list for non-aggregate, non-scalar type";
9279 break;
9280
9281 case FK_UserConversionOverloadFailed:
9282 OS << "overloading failed for user-defined conversion";
9283 break;
9284
9285 case FK_ConstructorOverloadFailed:
9286 OS << "constructor overloading failed";
9287 break;
9288
9289 case FK_DefaultInitOfConst:
9290 OS << "default initialization of a const variable";
9291 break;
9292
9293 case FK_Incomplete:
9294 OS << "initialization of incomplete type";
9295 break;
9296
9297 case FK_ListInitializationFailed:
9298 OS << "list initialization checker failure";
9299 break;
9300
9301 case FK_VariableLengthArrayHasInitializer:
9302 OS << "variable length array has an initializer";
9303 break;
9304
9305 case FK_PlaceholderType:
9306 OS << "initializer expression isn't contextually valid";
9307 break;
9308
9309 case FK_ListConstructorOverloadFailed:
9310 OS << "list constructor overloading failed";
9311 break;
9312
9313 case FK_ExplicitConstructor:
9314 OS << "list copy initialization chose explicit constructor";
9315 break;
9316 }
9317 OS << '\n';
9318 return;
9319 }
9320
9321 case DependentSequence:
9322 OS << "Dependent sequence\n";
9323 return;
9324
9325 case NormalSequence:
9326 OS << "Normal sequence: ";
9327 break;
9328 }
9329
9330 for (step_iterator S = step_begin(), SEnd = step_end(); S != SEnd; ++S) {
9331 if (S != step_begin()) {
9332 OS << " -> ";
9333 }
9334
9335 switch (S->Kind) {
9336 case SK_ResolveAddressOfOverloadedFunction:
9337 OS << "resolve address of overloaded function";
9338 break;
9339
9340 case SK_CastDerivedToBaseRValue:
9341 OS << "derived-to-base (rvalue)";
9342 break;
9343
9344 case SK_CastDerivedToBaseXValue:
9345 OS << "derived-to-base (xvalue)";
9346 break;
9347
9348 case SK_CastDerivedToBaseLValue:
9349 OS << "derived-to-base (lvalue)";
9350 break;
9351
9352 case SK_BindReference:
9353 OS << "bind reference to lvalue";
9354 break;
9355
9356 case SK_BindReferenceToTemporary:
9357 OS << "bind reference to a temporary";
9358 break;
9359
9360 case SK_FinalCopy:
9361 OS << "final copy in class direct-initialization";
9362 break;
9363
9364 case SK_ExtraneousCopyToTemporary:
9365 OS << "extraneous C++03 copy to temporary";
9366 break;
9367
9368 case SK_UserConversion:
9369 OS << "user-defined conversion via " << *S->Function.Function;
9370 break;
9371
9372 case SK_QualificationConversionRValue:
9373 OS << "qualification conversion (rvalue)";
9374 break;
9375
9376 case SK_QualificationConversionXValue:
9377 OS << "qualification conversion (xvalue)";
9378 break;
9379
9380 case SK_QualificationConversionLValue:
9381 OS << "qualification conversion (lvalue)";
9382 break;
9383
9384 case SK_AtomicConversion:
9385 OS << "non-atomic-to-atomic conversion";
9386 break;
9387
9388 case SK_ConversionSequence:
9389 OS << "implicit conversion sequence (";
9390 S->ICS->dump(); // FIXME: use OS
9391 OS << ")";
9392 break;
9393
9394 case SK_ConversionSequenceNoNarrowing:
9395 OS << "implicit conversion sequence with narrowing prohibited (";
9396 S->ICS->dump(); // FIXME: use OS
9397 OS << ")";
9398 break;
9399
9400 case SK_ListInitialization:
9401 OS << "list aggregate initialization";
9402 break;
9403
9404 case SK_UnwrapInitList:
9405 OS << "unwrap reference initializer list";
9406 break;
9407
9408 case SK_RewrapInitList:
9409 OS << "rewrap reference initializer list";
9410 break;
9411
9412 case SK_ConstructorInitialization:
9413 OS << "constructor initialization";
9414 break;
9415
9416 case SK_ConstructorInitializationFromList:
9417 OS << "list initialization via constructor";
9418 break;
9419
9420 case SK_ZeroInitialization:
9421 OS << "zero initialization";
9422 break;
9423
9424 case SK_CAssignment:
9425 OS << "C assignment";
9426 break;
9427
9428 case SK_StringInit:
9429 OS << "string initialization";
9430 break;
9431
9432 case SK_ObjCObjectConversion:
9433 OS << "Objective-C object conversion";
9434 break;
9435
9436 case SK_ArrayLoopIndex:
9437 OS << "indexing for array initialization loop";
9438 break;
9439
9440 case SK_ArrayLoopInit:
9441 OS << "array initialization loop";
9442 break;
9443
9444 case SK_ArrayInit:
9445 OS << "array initialization";
9446 break;
9447
9448 case SK_GNUArrayInit:
9449 OS << "array initialization (GNU extension)";
9450 break;
9451
9452 case SK_ParenthesizedArrayInit:
9453 OS << "parenthesized array initialization";
9454 break;
9455
9456 case SK_PassByIndirectCopyRestore:
9457 OS << "pass by indirect copy and restore";
9458 break;
9459
9460 case SK_PassByIndirectRestore:
9461 OS << "pass by indirect restore";
9462 break;
9463
9464 case SK_ProduceObjCObject:
9465 OS << "Objective-C object retension";
9466 break;
9467
9468 case SK_StdInitializerList:
9469 OS << "std::initializer_list from initializer list";
9470 break;
9471
9472 case SK_StdInitializerListConstructorCall:
9473 OS << "list initialization from std::initializer_list";
9474 break;
9475
9476 case SK_OCLSamplerInit:
9477 OS << "OpenCL sampler_t from integer constant";
9478 break;
9479
9480 case SK_OCLZeroOpaqueType:
9481 OS << "OpenCL opaque type from zero";
9482 break;
9483 }
9484
9485 OS << " [" << S->Type.getAsString() << ']';
9486 }
9487
9488 OS << '\n';
9489 }
9490
dump() const9491 void InitializationSequence::dump() const {
9492 dump(llvm::errs());
9493 }
9494
NarrowingErrs(const LangOptions & L)9495 static bool NarrowingErrs(const LangOptions &L) {
9496 return L.CPlusPlus11 &&
9497 (!L.MicrosoftExt || L.isCompatibleWithMSVC(LangOptions::MSVC2015));
9498 }
9499
DiagnoseNarrowingInInitList(Sema & S,const ImplicitConversionSequence & ICS,QualType PreNarrowingType,QualType EntityType,const Expr * PostInit)9500 static void DiagnoseNarrowingInInitList(Sema &S,
9501 const ImplicitConversionSequence &ICS,
9502 QualType PreNarrowingType,
9503 QualType EntityType,
9504 const Expr *PostInit) {
9505 const StandardConversionSequence *SCS = nullptr;
9506 switch (ICS.getKind()) {
9507 case ImplicitConversionSequence::StandardConversion:
9508 SCS = &ICS.Standard;
9509 break;
9510 case ImplicitConversionSequence::UserDefinedConversion:
9511 SCS = &ICS.UserDefined.After;
9512 break;
9513 case ImplicitConversionSequence::AmbiguousConversion:
9514 case ImplicitConversionSequence::EllipsisConversion:
9515 case ImplicitConversionSequence::BadConversion:
9516 return;
9517 }
9518
9519 // C++11 [dcl.init.list]p7: Check whether this is a narrowing conversion.
9520 APValue ConstantValue;
9521 QualType ConstantType;
9522 switch (SCS->getNarrowingKind(S.Context, PostInit, ConstantValue,
9523 ConstantType)) {
9524 case NK_Not_Narrowing:
9525 case NK_Dependent_Narrowing:
9526 // No narrowing occurred.
9527 return;
9528
9529 case NK_Type_Narrowing:
9530 // This was a floating-to-integer conversion, which is always considered a
9531 // narrowing conversion even if the value is a constant and can be
9532 // represented exactly as an integer.
9533 S.Diag(PostInit->getBeginLoc(), NarrowingErrs(S.getLangOpts())
9534 ? diag::ext_init_list_type_narrowing
9535 : diag::warn_init_list_type_narrowing)
9536 << PostInit->getSourceRange()
9537 << PreNarrowingType.getLocalUnqualifiedType()
9538 << EntityType.getLocalUnqualifiedType();
9539 break;
9540
9541 case NK_Constant_Narrowing:
9542 // A constant value was narrowed.
9543 S.Diag(PostInit->getBeginLoc(),
9544 NarrowingErrs(S.getLangOpts())
9545 ? diag::ext_init_list_constant_narrowing
9546 : diag::warn_init_list_constant_narrowing)
9547 << PostInit->getSourceRange()
9548 << ConstantValue.getAsString(S.getASTContext(), ConstantType)
9549 << EntityType.getLocalUnqualifiedType();
9550 break;
9551
9552 case NK_Variable_Narrowing:
9553 // A variable's value may have been narrowed.
9554 S.Diag(PostInit->getBeginLoc(),
9555 NarrowingErrs(S.getLangOpts())
9556 ? diag::ext_init_list_variable_narrowing
9557 : diag::warn_init_list_variable_narrowing)
9558 << PostInit->getSourceRange()
9559 << PreNarrowingType.getLocalUnqualifiedType()
9560 << EntityType.getLocalUnqualifiedType();
9561 break;
9562 }
9563
9564 SmallString<128> StaticCast;
9565 llvm::raw_svector_ostream OS(StaticCast);
9566 OS << "static_cast<";
9567 if (const TypedefType *TT = EntityType->getAs<TypedefType>()) {
9568 // It's important to use the typedef's name if there is one so that the
9569 // fixit doesn't break code using types like int64_t.
9570 //
9571 // FIXME: This will break if the typedef requires qualification. But
9572 // getQualifiedNameAsString() includes non-machine-parsable components.
9573 OS << *TT->getDecl();
9574 } else if (const BuiltinType *BT = EntityType->getAs<BuiltinType>())
9575 OS << BT->getName(S.getLangOpts());
9576 else {
9577 // Oops, we didn't find the actual type of the variable. Don't emit a fixit
9578 // with a broken cast.
9579 return;
9580 }
9581 OS << ">(";
9582 S.Diag(PostInit->getBeginLoc(), diag::note_init_list_narrowing_silence)
9583 << PostInit->getSourceRange()
9584 << FixItHint::CreateInsertion(PostInit->getBeginLoc(), OS.str())
9585 << FixItHint::CreateInsertion(
9586 S.getLocForEndOfToken(PostInit->getEndLoc()), ")");
9587 }
9588
9589 //===----------------------------------------------------------------------===//
9590 // Initialization helper functions
9591 //===----------------------------------------------------------------------===//
9592 bool
CanPerformCopyInitialization(const InitializedEntity & Entity,ExprResult Init)9593 Sema::CanPerformCopyInitialization(const InitializedEntity &Entity,
9594 ExprResult Init) {
9595 if (Init.isInvalid())
9596 return false;
9597
9598 Expr *InitE = Init.get();
9599 assert(InitE && "No initialization expression");
9600
9601 InitializationKind Kind =
9602 InitializationKind::CreateCopy(InitE->getBeginLoc(), SourceLocation());
9603 InitializationSequence Seq(*this, Entity, Kind, InitE);
9604 return !Seq.Failed();
9605 }
9606
9607 ExprResult
PerformCopyInitialization(const InitializedEntity & Entity,SourceLocation EqualLoc,ExprResult Init,bool TopLevelOfInitList,bool AllowExplicit)9608 Sema::PerformCopyInitialization(const InitializedEntity &Entity,
9609 SourceLocation EqualLoc,
9610 ExprResult Init,
9611 bool TopLevelOfInitList,
9612 bool AllowExplicit) {
9613 if (Init.isInvalid())
9614 return ExprError();
9615
9616 Expr *InitE = Init.get();
9617 assert(InitE && "No initialization expression?");
9618
9619 if (EqualLoc.isInvalid())
9620 EqualLoc = InitE->getBeginLoc();
9621
9622 InitializationKind Kind = InitializationKind::CreateCopy(
9623 InitE->getBeginLoc(), EqualLoc, AllowExplicit);
9624 InitializationSequence Seq(*this, Entity, Kind, InitE, TopLevelOfInitList);
9625
9626 // Prevent infinite recursion when performing parameter copy-initialization.
9627 const bool ShouldTrackCopy =
9628 Entity.isParameterKind() && Seq.isConstructorInitialization();
9629 if (ShouldTrackCopy) {
9630 if (llvm::find(CurrentParameterCopyTypes, Entity.getType()) !=
9631 CurrentParameterCopyTypes.end()) {
9632 Seq.SetOverloadFailure(
9633 InitializationSequence::FK_ConstructorOverloadFailed,
9634 OR_No_Viable_Function);
9635
9636 // Try to give a meaningful diagnostic note for the problematic
9637 // constructor.
9638 const auto LastStep = Seq.step_end() - 1;
9639 assert(LastStep->Kind ==
9640 InitializationSequence::SK_ConstructorInitialization);
9641 const FunctionDecl *Function = LastStep->Function.Function;
9642 auto Candidate =
9643 llvm::find_if(Seq.getFailedCandidateSet(),
9644 [Function](const OverloadCandidate &Candidate) -> bool {
9645 return Candidate.Viable &&
9646 Candidate.Function == Function &&
9647 Candidate.Conversions.size() > 0;
9648 });
9649 if (Candidate != Seq.getFailedCandidateSet().end() &&
9650 Function->getNumParams() > 0) {
9651 Candidate->Viable = false;
9652 Candidate->FailureKind = ovl_fail_bad_conversion;
9653 Candidate->Conversions[0].setBad(BadConversionSequence::no_conversion,
9654 InitE,
9655 Function->getParamDecl(0)->getType());
9656 }
9657 }
9658 CurrentParameterCopyTypes.push_back(Entity.getType());
9659 }
9660
9661 ExprResult Result = Seq.Perform(*this, Entity, Kind, InitE);
9662
9663 if (ShouldTrackCopy)
9664 CurrentParameterCopyTypes.pop_back();
9665
9666 return Result;
9667 }
9668
9669 /// Determine whether RD is, or is derived from, a specialization of CTD.
isOrIsDerivedFromSpecializationOf(CXXRecordDecl * RD,ClassTemplateDecl * CTD)9670 static bool isOrIsDerivedFromSpecializationOf(CXXRecordDecl *RD,
9671 ClassTemplateDecl *CTD) {
9672 auto NotSpecialization = [&] (const CXXRecordDecl *Candidate) {
9673 auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(Candidate);
9674 return !CTSD || !declaresSameEntity(CTSD->getSpecializedTemplate(), CTD);
9675 };
9676 return !(NotSpecialization(RD) && RD->forallBases(NotSpecialization));
9677 }
9678
DeduceTemplateSpecializationFromInitializer(TypeSourceInfo * TSInfo,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Inits)9679 QualType Sema::DeduceTemplateSpecializationFromInitializer(
9680 TypeSourceInfo *TSInfo, const InitializedEntity &Entity,
9681 const InitializationKind &Kind, MultiExprArg Inits) {
9682 auto *DeducedTST = dyn_cast<DeducedTemplateSpecializationType>(
9683 TSInfo->getType()->getContainedDeducedType());
9684 assert(DeducedTST && "not a deduced template specialization type");
9685
9686 auto TemplateName = DeducedTST->getTemplateName();
9687 if (TemplateName.isDependent())
9688 return Context.DependentTy;
9689
9690 // We can only perform deduction for class templates.
9691 auto *Template =
9692 dyn_cast_or_null<ClassTemplateDecl>(TemplateName.getAsTemplateDecl());
9693 if (!Template) {
9694 Diag(Kind.getLocation(),
9695 diag::err_deduced_non_class_template_specialization_type)
9696 << (int)getTemplateNameKindForDiagnostics(TemplateName) << TemplateName;
9697 if (auto *TD = TemplateName.getAsTemplateDecl())
9698 Diag(TD->getLocation(), diag::note_template_decl_here);
9699 return QualType();
9700 }
9701
9702 // Can't deduce from dependent arguments.
9703 if (Expr::hasAnyTypeDependentArguments(Inits)) {
9704 Diag(TSInfo->getTypeLoc().getBeginLoc(),
9705 diag::warn_cxx14_compat_class_template_argument_deduction)
9706 << TSInfo->getTypeLoc().getSourceRange() << 0;
9707 return Context.DependentTy;
9708 }
9709
9710 // FIXME: Perform "exact type" matching first, per CWG discussion?
9711 // Or implement this via an implied 'T(T) -> T' deduction guide?
9712
9713 // FIXME: Do we need/want a std::initializer_list<T> special case?
9714
9715 // Look up deduction guides, including those synthesized from constructors.
9716 //
9717 // C++1z [over.match.class.deduct]p1:
9718 // A set of functions and function templates is formed comprising:
9719 // - For each constructor of the class template designated by the
9720 // template-name, a function template [...]
9721 // - For each deduction-guide, a function or function template [...]
9722 DeclarationNameInfo NameInfo(
9723 Context.DeclarationNames.getCXXDeductionGuideName(Template),
9724 TSInfo->getTypeLoc().getEndLoc());
9725 LookupResult Guides(*this, NameInfo, LookupOrdinaryName);
9726 LookupQualifiedName(Guides, Template->getDeclContext());
9727
9728 // FIXME: Do not diagnose inaccessible deduction guides. The standard isn't
9729 // clear on this, but they're not found by name so access does not apply.
9730 Guides.suppressDiagnostics();
9731
9732 // Figure out if this is list-initialization.
9733 InitListExpr *ListInit =
9734 (Inits.size() == 1 && Kind.getKind() != InitializationKind::IK_Direct)
9735 ? dyn_cast<InitListExpr>(Inits[0])
9736 : nullptr;
9737
9738 // C++1z [over.match.class.deduct]p1:
9739 // Initialization and overload resolution are performed as described in
9740 // [dcl.init] and [over.match.ctor], [over.match.copy], or [over.match.list]
9741 // (as appropriate for the type of initialization performed) for an object
9742 // of a hypothetical class type, where the selected functions and function
9743 // templates are considered to be the constructors of that class type
9744 //
9745 // Since we know we're initializing a class type of a type unrelated to that
9746 // of the initializer, this reduces to something fairly reasonable.
9747 OverloadCandidateSet Candidates(Kind.getLocation(),
9748 OverloadCandidateSet::CSK_Normal);
9749 OverloadCandidateSet::iterator Best;
9750
9751 bool HasAnyDeductionGuide = false;
9752 bool AllowExplicit = !Kind.isCopyInit() || ListInit;
9753
9754 auto tryToResolveOverload =
9755 [&](bool OnlyListConstructors) -> OverloadingResult {
9756 Candidates.clear(OverloadCandidateSet::CSK_Normal);
9757 HasAnyDeductionGuide = false;
9758
9759 for (auto I = Guides.begin(), E = Guides.end(); I != E; ++I) {
9760 NamedDecl *D = (*I)->getUnderlyingDecl();
9761 if (D->isInvalidDecl())
9762 continue;
9763
9764 auto *TD = dyn_cast<FunctionTemplateDecl>(D);
9765 auto *GD = dyn_cast_or_null<CXXDeductionGuideDecl>(
9766 TD ? TD->getTemplatedDecl() : dyn_cast<FunctionDecl>(D));
9767 if (!GD)
9768 continue;
9769
9770 if (!GD->isImplicit())
9771 HasAnyDeductionGuide = true;
9772
9773 // C++ [over.match.ctor]p1: (non-list copy-initialization from non-class)
9774 // For copy-initialization, the candidate functions are all the
9775 // converting constructors (12.3.1) of that class.
9776 // C++ [over.match.copy]p1: (non-list copy-initialization from class)
9777 // The converting constructors of T are candidate functions.
9778 if (!AllowExplicit) {
9779 // Overload resolution checks whether the deduction guide is declared
9780 // explicit for us.
9781
9782 // When looking for a converting constructor, deduction guides that
9783 // could never be called with one argument are not interesting to
9784 // check or note.
9785 if (GD->getMinRequiredArguments() > 1 ||
9786 (GD->getNumParams() == 0 && !GD->isVariadic()))
9787 continue;
9788 }
9789
9790 // C++ [over.match.list]p1.1: (first phase list initialization)
9791 // Initially, the candidate functions are the initializer-list
9792 // constructors of the class T
9793 if (OnlyListConstructors && !isInitListConstructor(GD))
9794 continue;
9795
9796 // C++ [over.match.list]p1.2: (second phase list initialization)
9797 // the candidate functions are all the constructors of the class T
9798 // C++ [over.match.ctor]p1: (all other cases)
9799 // the candidate functions are all the constructors of the class of
9800 // the object being initialized
9801
9802 // C++ [over.best.ics]p4:
9803 // When [...] the constructor [...] is a candidate by
9804 // - [over.match.copy] (in all cases)
9805 // FIXME: The "second phase of [over.match.list] case can also
9806 // theoretically happen here, but it's not clear whether we can
9807 // ever have a parameter of the right type.
9808 bool SuppressUserConversions = Kind.isCopyInit();
9809
9810 if (TD)
9811 AddTemplateOverloadCandidate(TD, I.getPair(), /*ExplicitArgs*/ nullptr,
9812 Inits, Candidates, SuppressUserConversions,
9813 /*PartialOverloading*/ false,
9814 AllowExplicit);
9815 else
9816 AddOverloadCandidate(GD, I.getPair(), Inits, Candidates,
9817 SuppressUserConversions,
9818 /*PartialOverloading*/ false, AllowExplicit);
9819 }
9820 return Candidates.BestViableFunction(*this, Kind.getLocation(), Best);
9821 };
9822
9823 OverloadingResult Result = OR_No_Viable_Function;
9824
9825 // C++11 [over.match.list]p1, per DR1467: for list-initialization, first
9826 // try initializer-list constructors.
9827 if (ListInit) {
9828 bool TryListConstructors = true;
9829
9830 // Try list constructors unless the list is empty and the class has one or
9831 // more default constructors, in which case those constructors win.
9832 if (!ListInit->getNumInits()) {
9833 for (NamedDecl *D : Guides) {
9834 auto *FD = dyn_cast<FunctionDecl>(D->getUnderlyingDecl());
9835 if (FD && FD->getMinRequiredArguments() == 0) {
9836 TryListConstructors = false;
9837 break;
9838 }
9839 }
9840 } else if (ListInit->getNumInits() == 1) {
9841 // C++ [over.match.class.deduct]:
9842 // As an exception, the first phase in [over.match.list] (considering
9843 // initializer-list constructors) is omitted if the initializer list
9844 // consists of a single expression of type cv U, where U is a
9845 // specialization of C or a class derived from a specialization of C.
9846 Expr *E = ListInit->getInit(0);
9847 auto *RD = E->getType()->getAsCXXRecordDecl();
9848 if (!isa<InitListExpr>(E) && RD &&
9849 isCompleteType(Kind.getLocation(), E->getType()) &&
9850 isOrIsDerivedFromSpecializationOf(RD, Template))
9851 TryListConstructors = false;
9852 }
9853
9854 if (TryListConstructors)
9855 Result = tryToResolveOverload(/*OnlyListConstructor*/true);
9856 // Then unwrap the initializer list and try again considering all
9857 // constructors.
9858 Inits = MultiExprArg(ListInit->getInits(), ListInit->getNumInits());
9859 }
9860
9861 // If list-initialization fails, or if we're doing any other kind of
9862 // initialization, we (eventually) consider constructors.
9863 if (Result == OR_No_Viable_Function)
9864 Result = tryToResolveOverload(/*OnlyListConstructor*/false);
9865
9866 switch (Result) {
9867 case OR_Ambiguous:
9868 // FIXME: For list-initialization candidates, it'd usually be better to
9869 // list why they were not viable when given the initializer list itself as
9870 // an argument.
9871 Candidates.NoteCandidates(
9872 PartialDiagnosticAt(
9873 Kind.getLocation(),
9874 PDiag(diag::err_deduced_class_template_ctor_ambiguous)
9875 << TemplateName),
9876 *this, OCD_AmbiguousCandidates, Inits);
9877 return QualType();
9878
9879 case OR_No_Viable_Function: {
9880 CXXRecordDecl *Primary =
9881 cast<ClassTemplateDecl>(Template)->getTemplatedDecl();
9882 bool Complete =
9883 isCompleteType(Kind.getLocation(), Context.getTypeDeclType(Primary));
9884 Candidates.NoteCandidates(
9885 PartialDiagnosticAt(
9886 Kind.getLocation(),
9887 PDiag(Complete ? diag::err_deduced_class_template_ctor_no_viable
9888 : diag::err_deduced_class_template_incomplete)
9889 << TemplateName << !Guides.empty()),
9890 *this, OCD_AllCandidates, Inits);
9891 return QualType();
9892 }
9893
9894 case OR_Deleted: {
9895 Diag(Kind.getLocation(), diag::err_deduced_class_template_deleted)
9896 << TemplateName;
9897 NoteDeletedFunction(Best->Function);
9898 return QualType();
9899 }
9900
9901 case OR_Success:
9902 // C++ [over.match.list]p1:
9903 // In copy-list-initialization, if an explicit constructor is chosen, the
9904 // initialization is ill-formed.
9905 if (Kind.isCopyInit() && ListInit &&
9906 cast<CXXDeductionGuideDecl>(Best->Function)->isExplicit()) {
9907 bool IsDeductionGuide = !Best->Function->isImplicit();
9908 Diag(Kind.getLocation(), diag::err_deduced_class_template_explicit)
9909 << TemplateName << IsDeductionGuide;
9910 Diag(Best->Function->getLocation(),
9911 diag::note_explicit_ctor_deduction_guide_here)
9912 << IsDeductionGuide;
9913 return QualType();
9914 }
9915
9916 // Make sure we didn't select an unusable deduction guide, and mark it
9917 // as referenced.
9918 DiagnoseUseOfDecl(Best->Function, Kind.getLocation());
9919 MarkFunctionReferenced(Kind.getLocation(), Best->Function);
9920 break;
9921 }
9922
9923 // C++ [dcl.type.class.deduct]p1:
9924 // The placeholder is replaced by the return type of the function selected
9925 // by overload resolution for class template deduction.
9926 QualType DeducedType =
9927 SubstAutoType(TSInfo->getType(), Best->Function->getReturnType());
9928 Diag(TSInfo->getTypeLoc().getBeginLoc(),
9929 diag::warn_cxx14_compat_class_template_argument_deduction)
9930 << TSInfo->getTypeLoc().getSourceRange() << 1 << DeducedType;
9931
9932 // Warn if CTAD was used on a type that does not have any user-defined
9933 // deduction guides.
9934 if (!HasAnyDeductionGuide) {
9935 Diag(TSInfo->getTypeLoc().getBeginLoc(),
9936 diag::warn_ctad_maybe_unsupported)
9937 << TemplateName;
9938 Diag(Template->getLocation(), diag::note_suppress_ctad_maybe_unsupported);
9939 }
9940
9941 return DeducedType;
9942 }
9943