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/SourceManager.h"
21 #include "clang/Basic/TargetInfo.h"
22 #include "clang/Sema/Designator.h"
23 #include "clang/Sema/Initialization.h"
24 #include "clang/Sema/Lookup.h"
25 #include "clang/Sema/SemaInternal.h"
26 #include "llvm/ADT/APInt.h"
27 #include "llvm/ADT/SmallString.h"
28 #include "llvm/Support/ErrorHandling.h"
29 #include "llvm/Support/raw_ostream.h"
30
31 using namespace clang;
32
33 //===----------------------------------------------------------------------===//
34 // Sema Initialization Checking
35 //===----------------------------------------------------------------------===//
36
37 /// Check whether T is compatible with a wide character type (wchar_t,
38 /// char16_t or char32_t).
IsWideCharCompatible(QualType T,ASTContext & Context)39 static bool IsWideCharCompatible(QualType T, ASTContext &Context) {
40 if (Context.typesAreCompatible(Context.getWideCharType(), T))
41 return true;
42 if (Context.getLangOpts().CPlusPlus || Context.getLangOpts().C11) {
43 return Context.typesAreCompatible(Context.Char16Ty, T) ||
44 Context.typesAreCompatible(Context.Char32Ty, T);
45 }
46 return false;
47 }
48
49 enum StringInitFailureKind {
50 SIF_None,
51 SIF_NarrowStringIntoWideChar,
52 SIF_WideStringIntoChar,
53 SIF_IncompatWideStringIntoWideChar,
54 SIF_UTF8StringIntoPlainChar,
55 SIF_PlainStringIntoUTF8Char,
56 SIF_Other
57 };
58
59 /// Check whether the array of type AT can be initialized by the Init
60 /// expression by means of string initialization. Returns SIF_None if so,
61 /// otherwise returns a StringInitFailureKind that describes why the
62 /// initialization would not work.
IsStringInit(Expr * Init,const ArrayType * AT,ASTContext & Context)63 static StringInitFailureKind IsStringInit(Expr *Init, const ArrayType *AT,
64 ASTContext &Context) {
65 if (!isa<ConstantArrayType>(AT) && !isa<IncompleteArrayType>(AT))
66 return SIF_Other;
67
68 // See if this is a string literal or @encode.
69 Init = Init->IgnoreParens();
70
71 // Handle @encode, which is a narrow string.
72 if (isa<ObjCEncodeExpr>(Init) && AT->getElementType()->isCharType())
73 return SIF_None;
74
75 // Otherwise we can only handle string literals.
76 StringLiteral *SL = dyn_cast<StringLiteral>(Init);
77 if (!SL)
78 return SIF_Other;
79
80 const QualType ElemTy =
81 Context.getCanonicalType(AT->getElementType()).getUnqualifiedType();
82
83 switch (SL->getKind()) {
84 case StringLiteral::UTF8:
85 // char8_t array can be initialized with a UTF-8 string.
86 if (ElemTy->isChar8Type())
87 return SIF_None;
88 LLVM_FALLTHROUGH;
89 case StringLiteral::Ascii:
90 // char array can be initialized with a narrow string.
91 // Only allow char x[] = "foo"; not char x[] = L"foo";
92 if (ElemTy->isCharType())
93 return (SL->getKind() == StringLiteral::UTF8 &&
94 Context.getLangOpts().Char8)
95 ? SIF_UTF8StringIntoPlainChar
96 : SIF_None;
97 if (ElemTy->isChar8Type())
98 return SIF_PlainStringIntoUTF8Char;
99 if (IsWideCharCompatible(ElemTy, Context))
100 return SIF_NarrowStringIntoWideChar;
101 return SIF_Other;
102 // C99 6.7.8p15 (with correction from DR343), or C11 6.7.9p15:
103 // "An array with element type compatible with a qualified or unqualified
104 // version of wchar_t, char16_t, or char32_t may be initialized by a wide
105 // string literal with the corresponding encoding prefix (L, u, or U,
106 // respectively), optionally enclosed in braces.
107 case StringLiteral::UTF16:
108 if (Context.typesAreCompatible(Context.Char16Ty, ElemTy))
109 return SIF_None;
110 if (ElemTy->isCharType() || ElemTy->isChar8Type())
111 return SIF_WideStringIntoChar;
112 if (IsWideCharCompatible(ElemTy, Context))
113 return SIF_IncompatWideStringIntoWideChar;
114 return SIF_Other;
115 case StringLiteral::UTF32:
116 if (Context.typesAreCompatible(Context.Char32Ty, ElemTy))
117 return SIF_None;
118 if (ElemTy->isCharType() || ElemTy->isChar8Type())
119 return SIF_WideStringIntoChar;
120 if (IsWideCharCompatible(ElemTy, Context))
121 return SIF_IncompatWideStringIntoWideChar;
122 return SIF_Other;
123 case StringLiteral::Wide:
124 if (Context.typesAreCompatible(Context.getWideCharType(), ElemTy))
125 return SIF_None;
126 if (ElemTy->isCharType() || ElemTy->isChar8Type())
127 return SIF_WideStringIntoChar;
128 if (IsWideCharCompatible(ElemTy, Context))
129 return SIF_IncompatWideStringIntoWideChar;
130 return SIF_Other;
131 }
132
133 llvm_unreachable("missed a StringLiteral kind?");
134 }
135
IsStringInit(Expr * init,QualType declType,ASTContext & Context)136 static StringInitFailureKind IsStringInit(Expr *init, QualType declType,
137 ASTContext &Context) {
138 const ArrayType *arrayType = Context.getAsArrayType(declType);
139 if (!arrayType)
140 return SIF_Other;
141 return IsStringInit(init, arrayType, Context);
142 }
143
144 /// Update the type of a string literal, including any surrounding parentheses,
145 /// to match the type of the object which it is initializing.
updateStringLiteralType(Expr * E,QualType Ty)146 static void updateStringLiteralType(Expr *E, QualType Ty) {
147 while (true) {
148 E->setType(Ty);
149 E->setValueKind(VK_RValue);
150 if (isa<StringLiteral>(E) || isa<ObjCEncodeExpr>(E)) {
151 break;
152 } else if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
153 E = PE->getSubExpr();
154 } else if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
155 assert(UO->getOpcode() == UO_Extension);
156 E = UO->getSubExpr();
157 } else if (GenericSelectionExpr *GSE = dyn_cast<GenericSelectionExpr>(E)) {
158 E = GSE->getResultExpr();
159 } else if (ChooseExpr *CE = dyn_cast<ChooseExpr>(E)) {
160 E = CE->getChosenSubExpr();
161 } else {
162 llvm_unreachable("unexpected expr in string literal init");
163 }
164 }
165 }
166
167 /// Fix a compound literal initializing an array so it's correctly marked
168 /// as an rvalue.
updateGNUCompoundLiteralRValue(Expr * E)169 static void updateGNUCompoundLiteralRValue(Expr *E) {
170 while (true) {
171 E->setValueKind(VK_RValue);
172 if (isa<CompoundLiteralExpr>(E)) {
173 break;
174 } else if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
175 E = PE->getSubExpr();
176 } else if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
177 assert(UO->getOpcode() == UO_Extension);
178 E = UO->getSubExpr();
179 } else if (GenericSelectionExpr *GSE = dyn_cast<GenericSelectionExpr>(E)) {
180 E = GSE->getResultExpr();
181 } else if (ChooseExpr *CE = dyn_cast<ChooseExpr>(E)) {
182 E = CE->getChosenSubExpr();
183 } else {
184 llvm_unreachable("unexpected expr in array compound literal init");
185 }
186 }
187 }
188
CheckStringInit(Expr * Str,QualType & DeclT,const ArrayType * AT,Sema & S)189 static void CheckStringInit(Expr *Str, QualType &DeclT, const ArrayType *AT,
190 Sema &S) {
191 // Get the length of the string as parsed.
192 auto *ConstantArrayTy =
193 cast<ConstantArrayType>(Str->getType()->getAsArrayTypeUnsafe());
194 uint64_t StrLength = ConstantArrayTy->getSize().getZExtValue();
195
196 if (const IncompleteArrayType *IAT = dyn_cast<IncompleteArrayType>(AT)) {
197 // C99 6.7.8p14. We have an array of character type with unknown size
198 // being initialized to a string literal.
199 llvm::APInt ConstVal(32, StrLength);
200 // Return a new array type (C99 6.7.8p22).
201 DeclT = S.Context.getConstantArrayType(IAT->getElementType(),
202 ConstVal, nullptr,
203 ArrayType::Normal, 0);
204 updateStringLiteralType(Str, DeclT);
205 return;
206 }
207
208 const ConstantArrayType *CAT = cast<ConstantArrayType>(AT);
209
210 // We have an array of character type with known size. However,
211 // the size may be smaller or larger than the string we are initializing.
212 // FIXME: Avoid truncation for 64-bit length strings.
213 if (S.getLangOpts().CPlusPlus) {
214 if (StringLiteral *SL = dyn_cast<StringLiteral>(Str->IgnoreParens())) {
215 // For Pascal strings it's OK to strip off the terminating null character,
216 // so the example below is valid:
217 //
218 // unsigned char a[2] = "\pa";
219 if (SL->isPascal())
220 StrLength--;
221 }
222
223 // [dcl.init.string]p2
224 if (StrLength > CAT->getSize().getZExtValue())
225 S.Diag(Str->getBeginLoc(),
226 diag::err_initializer_string_for_char_array_too_long)
227 << Str->getSourceRange();
228 } else {
229 // C99 6.7.8p14.
230 if (StrLength-1 > CAT->getSize().getZExtValue())
231 S.Diag(Str->getBeginLoc(),
232 diag::ext_initializer_string_for_char_array_too_long)
233 << Str->getSourceRange();
234 }
235
236 // Set the type to the actual size that we are initializing. If we have
237 // something like:
238 // char x[1] = "foo";
239 // then this will set the string literal's type to char[1].
240 updateStringLiteralType(Str, DeclT);
241 }
242
243 //===----------------------------------------------------------------------===//
244 // Semantic checking for initializer lists.
245 //===----------------------------------------------------------------------===//
246
247 namespace {
248
249 /// Semantic checking for initializer lists.
250 ///
251 /// The InitListChecker class contains a set of routines that each
252 /// handle the initialization of a certain kind of entity, e.g.,
253 /// arrays, vectors, struct/union types, scalars, etc. The
254 /// InitListChecker itself performs a recursive walk of the subobject
255 /// structure of the type to be initialized, while stepping through
256 /// the initializer list one element at a time. The IList and Index
257 /// parameters to each of the Check* routines contain the active
258 /// (syntactic) initializer list and the index into that initializer
259 /// list that represents the current initializer. Each routine is
260 /// responsible for moving that Index forward as it consumes elements.
261 ///
262 /// Each Check* routine also has a StructuredList/StructuredIndex
263 /// arguments, which contains the current "structured" (semantic)
264 /// initializer list and the index into that initializer list where we
265 /// are copying initializers as we map them over to the semantic
266 /// list. Once we have completed our recursive walk of the subobject
267 /// structure, we will have constructed a full semantic initializer
268 /// list.
269 ///
270 /// C99 designators cause changes in the initializer list traversal,
271 /// because they make the initialization "jump" into a specific
272 /// subobject and then continue the initialization from that
273 /// point. CheckDesignatedInitializer() recursively steps into the
274 /// designated subobject and manages backing out the recursion to
275 /// initialize the subobjects after the one designated.
276 ///
277 /// If an initializer list contains any designators, we build a placeholder
278 /// structured list even in 'verify only' mode, so that we can track which
279 /// elements need 'empty' initializtion.
280 class InitListChecker {
281 Sema &SemaRef;
282 bool hadError = false;
283 bool VerifyOnly; // No diagnostics.
284 bool TreatUnavailableAsInvalid; // Used only in VerifyOnly mode.
285 bool InOverloadResolution;
286 InitListExpr *FullyStructuredList = nullptr;
287 NoInitExpr *DummyExpr = nullptr;
288
getDummyInit()289 NoInitExpr *getDummyInit() {
290 if (!DummyExpr)
291 DummyExpr = new (SemaRef.Context) NoInitExpr(SemaRef.Context.VoidTy);
292 return DummyExpr;
293 }
294
295 void CheckImplicitInitList(const InitializedEntity &Entity,
296 InitListExpr *ParentIList, QualType T,
297 unsigned &Index, InitListExpr *StructuredList,
298 unsigned &StructuredIndex);
299 void CheckExplicitInitList(const InitializedEntity &Entity,
300 InitListExpr *IList, QualType &T,
301 InitListExpr *StructuredList,
302 bool TopLevelObject = false);
303 void CheckListElementTypes(const InitializedEntity &Entity,
304 InitListExpr *IList, QualType &DeclType,
305 bool SubobjectIsDesignatorContext,
306 unsigned &Index,
307 InitListExpr *StructuredList,
308 unsigned &StructuredIndex,
309 bool TopLevelObject = false);
310 void CheckSubElementType(const InitializedEntity &Entity,
311 InitListExpr *IList, QualType ElemType,
312 unsigned &Index,
313 InitListExpr *StructuredList,
314 unsigned &StructuredIndex);
315 void CheckComplexType(const InitializedEntity &Entity,
316 InitListExpr *IList, QualType DeclType,
317 unsigned &Index,
318 InitListExpr *StructuredList,
319 unsigned &StructuredIndex);
320 void CheckScalarType(const InitializedEntity &Entity,
321 InitListExpr *IList, QualType DeclType,
322 unsigned &Index,
323 InitListExpr *StructuredList,
324 unsigned &StructuredIndex);
325 void CheckReferenceType(const InitializedEntity &Entity,
326 InitListExpr *IList, QualType DeclType,
327 unsigned &Index,
328 InitListExpr *StructuredList,
329 unsigned &StructuredIndex);
330 void CheckVectorType(const InitializedEntity &Entity,
331 InitListExpr *IList, QualType DeclType, unsigned &Index,
332 InitListExpr *StructuredList,
333 unsigned &StructuredIndex);
334 void CheckStructUnionTypes(const InitializedEntity &Entity,
335 InitListExpr *IList, QualType DeclType,
336 CXXRecordDecl::base_class_range Bases,
337 RecordDecl::field_iterator Field,
338 bool SubobjectIsDesignatorContext, unsigned &Index,
339 InitListExpr *StructuredList,
340 unsigned &StructuredIndex,
341 bool TopLevelObject = false);
342 void CheckArrayType(const InitializedEntity &Entity,
343 InitListExpr *IList, QualType &DeclType,
344 llvm::APSInt elementIndex,
345 bool SubobjectIsDesignatorContext, unsigned &Index,
346 InitListExpr *StructuredList,
347 unsigned &StructuredIndex);
348 bool CheckDesignatedInitializer(const InitializedEntity &Entity,
349 InitListExpr *IList, DesignatedInitExpr *DIE,
350 unsigned DesigIdx,
351 QualType &CurrentObjectType,
352 RecordDecl::field_iterator *NextField,
353 llvm::APSInt *NextElementIndex,
354 unsigned &Index,
355 InitListExpr *StructuredList,
356 unsigned &StructuredIndex,
357 bool FinishSubobjectInit,
358 bool TopLevelObject);
359 InitListExpr *getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
360 QualType CurrentObjectType,
361 InitListExpr *StructuredList,
362 unsigned StructuredIndex,
363 SourceRange InitRange,
364 bool IsFullyOverwritten = false);
365 void UpdateStructuredListElement(InitListExpr *StructuredList,
366 unsigned &StructuredIndex,
367 Expr *expr);
368 InitListExpr *createInitListExpr(QualType CurrentObjectType,
369 SourceRange InitRange,
370 unsigned ExpectedNumInits);
371 int numArrayElements(QualType DeclType);
372 int numStructUnionElements(QualType DeclType);
373
374 ExprResult PerformEmptyInit(SourceLocation Loc,
375 const InitializedEntity &Entity);
376
377 /// Diagnose that OldInit (or part thereof) has been overridden by NewInit.
diagnoseInitOverride(Expr * OldInit,SourceRange NewInitRange,bool FullyOverwritten=true)378 void diagnoseInitOverride(Expr *OldInit, SourceRange NewInitRange,
379 bool FullyOverwritten = true) {
380 // Overriding an initializer via a designator is valid with C99 designated
381 // initializers, but ill-formed with C++20 designated initializers.
382 unsigned DiagID = SemaRef.getLangOpts().CPlusPlus
383 ? diag::ext_initializer_overrides
384 : diag::warn_initializer_overrides;
385
386 if (InOverloadResolution && SemaRef.getLangOpts().CPlusPlus) {
387 // In overload resolution, we have to strictly enforce the rules, and so
388 // don't allow any overriding of prior initializers. This matters for a
389 // case such as:
390 //
391 // union U { int a, b; };
392 // struct S { int a, b; };
393 // void f(U), f(S);
394 //
395 // Here, f({.a = 1, .b = 2}) is required to call the struct overload. For
396 // consistency, we disallow all overriding of prior initializers in
397 // overload resolution, not only overriding of union members.
398 hadError = true;
399 } else if (OldInit->getType().isDestructedType() && !FullyOverwritten) {
400 // If we'll be keeping around the old initializer but overwriting part of
401 // the object it initialized, and that object is not trivially
402 // destructible, this can leak. Don't allow that, not even as an
403 // extension.
404 //
405 // FIXME: It might be reasonable to allow this in cases where the part of
406 // the initializer that we're overriding has trivial destruction.
407 DiagID = diag::err_initializer_overrides_destructed;
408 } else if (!OldInit->getSourceRange().isValid()) {
409 // We need to check on source range validity because the previous
410 // initializer does not have to be an explicit initializer. e.g.,
411 //
412 // struct P { int a, b; };
413 // struct PP { struct P p } l = { { .a = 2 }, .p.b = 3 };
414 //
415 // There is an overwrite taking place because the first braced initializer
416 // list "{ .a = 2 }" already provides value for .p.b (which is zero).
417 //
418 // Such overwrites are harmless, so we don't diagnose them. (Note that in
419 // C++, this cannot be reached unless we've already seen and diagnosed a
420 // different conformance issue, such as a mixture of designated and
421 // non-designated initializers or a multi-level designator.)
422 return;
423 }
424
425 if (!VerifyOnly) {
426 SemaRef.Diag(NewInitRange.getBegin(), DiagID)
427 << NewInitRange << FullyOverwritten << OldInit->getType();
428 SemaRef.Diag(OldInit->getBeginLoc(), diag::note_previous_initializer)
429 << (OldInit->HasSideEffects(SemaRef.Context) && FullyOverwritten)
430 << OldInit->getSourceRange();
431 }
432 }
433
434 // Explanation on the "FillWithNoInit" mode:
435 //
436 // Assume we have the following definitions (Case#1):
437 // struct P { char x[6][6]; } xp = { .x[1] = "bar" };
438 // struct PP { struct P lp; } l = { .lp = xp, .lp.x[1][2] = 'f' };
439 //
440 // l.lp.x[1][0..1] should not be filled with implicit initializers because the
441 // "base" initializer "xp" will provide values for them; l.lp.x[1] will be "baf".
442 //
443 // But if we have (Case#2):
444 // struct PP l = { .lp = xp, .lp.x[1] = { [2] = 'f' } };
445 //
446 // l.lp.x[1][0..1] are implicitly initialized and do not use values from the
447 // "base" initializer; l.lp.x[1] will be "\0\0f\0\0\0".
448 //
449 // To distinguish Case#1 from Case#2, and also to avoid leaving many "holes"
450 // in the InitListExpr, the "holes" in Case#1 are filled not with empty
451 // initializers but with special "NoInitExpr" place holders, which tells the
452 // CodeGen not to generate any initializers for these parts.
453 void FillInEmptyInitForBase(unsigned Init, const CXXBaseSpecifier &Base,
454 const InitializedEntity &ParentEntity,
455 InitListExpr *ILE, bool &RequiresSecondPass,
456 bool FillWithNoInit);
457 void FillInEmptyInitForField(unsigned Init, FieldDecl *Field,
458 const InitializedEntity &ParentEntity,
459 InitListExpr *ILE, bool &RequiresSecondPass,
460 bool FillWithNoInit = false);
461 void FillInEmptyInitializations(const InitializedEntity &Entity,
462 InitListExpr *ILE, bool &RequiresSecondPass,
463 InitListExpr *OuterILE, unsigned OuterIndex,
464 bool FillWithNoInit = false);
465 bool CheckFlexibleArrayInit(const InitializedEntity &Entity,
466 Expr *InitExpr, FieldDecl *Field,
467 bool TopLevelObject);
468 void CheckEmptyInitializable(const InitializedEntity &Entity,
469 SourceLocation Loc);
470
471 public:
472 InitListChecker(Sema &S, const InitializedEntity &Entity, InitListExpr *IL,
473 QualType &T, bool VerifyOnly, bool TreatUnavailableAsInvalid,
474 bool InOverloadResolution = false);
HadError()475 bool HadError() { return hadError; }
476
477 // Retrieves the fully-structured initializer list used for
478 // semantic analysis and code generation.
getFullyStructuredList() const479 InitListExpr *getFullyStructuredList() const { return FullyStructuredList; }
480 };
481
482 } // end anonymous namespace
483
PerformEmptyInit(SourceLocation Loc,const InitializedEntity & Entity)484 ExprResult InitListChecker::PerformEmptyInit(SourceLocation Loc,
485 const InitializedEntity &Entity) {
486 InitializationKind Kind = InitializationKind::CreateValue(Loc, Loc, Loc,
487 true);
488 MultiExprArg SubInit;
489 Expr *InitExpr;
490 InitListExpr DummyInitList(SemaRef.Context, Loc, None, Loc);
491
492 // C++ [dcl.init.aggr]p7:
493 // If there are fewer initializer-clauses in the list than there are
494 // members in the aggregate, then each member not explicitly initialized
495 // ...
496 bool EmptyInitList = SemaRef.getLangOpts().CPlusPlus11 &&
497 Entity.getType()->getBaseElementTypeUnsafe()->isRecordType();
498 if (EmptyInitList) {
499 // C++1y / DR1070:
500 // shall be initialized [...] from an empty initializer list.
501 //
502 // We apply the resolution of this DR to C++11 but not C++98, since C++98
503 // does not have useful semantics for initialization from an init list.
504 // We treat this as copy-initialization, because aggregate initialization
505 // always performs copy-initialization on its elements.
506 //
507 // Only do this if we're initializing a class type, to avoid filling in
508 // the initializer list where possible.
509 InitExpr = VerifyOnly ? &DummyInitList : new (SemaRef.Context)
510 InitListExpr(SemaRef.Context, Loc, None, Loc);
511 InitExpr->setType(SemaRef.Context.VoidTy);
512 SubInit = InitExpr;
513 Kind = InitializationKind::CreateCopy(Loc, Loc);
514 } else {
515 // C++03:
516 // shall be value-initialized.
517 }
518
519 InitializationSequence InitSeq(SemaRef, Entity, Kind, SubInit);
520 // libstdc++4.6 marks the vector default constructor as explicit in
521 // _GLIBCXX_DEBUG mode, so recover using the C++03 logic in that case.
522 // stlport does so too. Look for std::__debug for libstdc++, and for
523 // std:: for stlport. This is effectively a compiler-side implementation of
524 // LWG2193.
525 if (!InitSeq && EmptyInitList && InitSeq.getFailureKind() ==
526 InitializationSequence::FK_ExplicitConstructor) {
527 OverloadCandidateSet::iterator Best;
528 OverloadingResult O =
529 InitSeq.getFailedCandidateSet()
530 .BestViableFunction(SemaRef, Kind.getLocation(), Best);
531 (void)O;
532 assert(O == OR_Success && "Inconsistent overload resolution");
533 CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
534 CXXRecordDecl *R = CtorDecl->getParent();
535
536 if (CtorDecl->getMinRequiredArguments() == 0 &&
537 CtorDecl->isExplicit() && R->getDeclName() &&
538 SemaRef.SourceMgr.isInSystemHeader(CtorDecl->getLocation())) {
539 bool IsInStd = false;
540 for (NamespaceDecl *ND = dyn_cast<NamespaceDecl>(R->getDeclContext());
541 ND && !IsInStd; ND = dyn_cast<NamespaceDecl>(ND->getParent())) {
542 if (SemaRef.getStdNamespace()->InEnclosingNamespaceSetOf(ND))
543 IsInStd = true;
544 }
545
546 if (IsInStd && llvm::StringSwitch<bool>(R->getName())
547 .Cases("basic_string", "deque", "forward_list", true)
548 .Cases("list", "map", "multimap", "multiset", true)
549 .Cases("priority_queue", "queue", "set", "stack", true)
550 .Cases("unordered_map", "unordered_set", "vector", true)
551 .Default(false)) {
552 InitSeq.InitializeFrom(
553 SemaRef, Entity,
554 InitializationKind::CreateValue(Loc, Loc, Loc, true),
555 MultiExprArg(), /*TopLevelOfInitList=*/false,
556 TreatUnavailableAsInvalid);
557 // Emit a warning for this. System header warnings aren't shown
558 // by default, but people working on system headers should see it.
559 if (!VerifyOnly) {
560 SemaRef.Diag(CtorDecl->getLocation(),
561 diag::warn_invalid_initializer_from_system_header);
562 if (Entity.getKind() == InitializedEntity::EK_Member)
563 SemaRef.Diag(Entity.getDecl()->getLocation(),
564 diag::note_used_in_initialization_here);
565 else if (Entity.getKind() == InitializedEntity::EK_ArrayElement)
566 SemaRef.Diag(Loc, diag::note_used_in_initialization_here);
567 }
568 }
569 }
570 }
571 if (!InitSeq) {
572 if (!VerifyOnly) {
573 InitSeq.Diagnose(SemaRef, Entity, Kind, SubInit);
574 if (Entity.getKind() == InitializedEntity::EK_Member)
575 SemaRef.Diag(Entity.getDecl()->getLocation(),
576 diag::note_in_omitted_aggregate_initializer)
577 << /*field*/1 << Entity.getDecl();
578 else if (Entity.getKind() == InitializedEntity::EK_ArrayElement) {
579 bool IsTrailingArrayNewMember =
580 Entity.getParent() &&
581 Entity.getParent()->isVariableLengthArrayNew();
582 SemaRef.Diag(Loc, diag::note_in_omitted_aggregate_initializer)
583 << (IsTrailingArrayNewMember ? 2 : /*array element*/0)
584 << Entity.getElementIndex();
585 }
586 }
587 hadError = true;
588 return ExprError();
589 }
590
591 return VerifyOnly ? ExprResult()
592 : InitSeq.Perform(SemaRef, Entity, Kind, SubInit);
593 }
594
CheckEmptyInitializable(const InitializedEntity & Entity,SourceLocation Loc)595 void InitListChecker::CheckEmptyInitializable(const InitializedEntity &Entity,
596 SourceLocation Loc) {
597 // If we're building a fully-structured list, we'll check this at the end
598 // once we know which elements are actually initialized. Otherwise, we know
599 // that there are no designators so we can just check now.
600 if (FullyStructuredList)
601 return;
602 PerformEmptyInit(Loc, Entity);
603 }
604
FillInEmptyInitForBase(unsigned Init,const CXXBaseSpecifier & Base,const InitializedEntity & ParentEntity,InitListExpr * ILE,bool & RequiresSecondPass,bool FillWithNoInit)605 void InitListChecker::FillInEmptyInitForBase(
606 unsigned Init, const CXXBaseSpecifier &Base,
607 const InitializedEntity &ParentEntity, InitListExpr *ILE,
608 bool &RequiresSecondPass, bool FillWithNoInit) {
609 InitializedEntity BaseEntity = InitializedEntity::InitializeBase(
610 SemaRef.Context, &Base, false, &ParentEntity);
611
612 if (Init >= ILE->getNumInits() || !ILE->getInit(Init)) {
613 ExprResult BaseInit = FillWithNoInit
614 ? new (SemaRef.Context) NoInitExpr(Base.getType())
615 : PerformEmptyInit(ILE->getEndLoc(), BaseEntity);
616 if (BaseInit.isInvalid()) {
617 hadError = true;
618 return;
619 }
620
621 if (!VerifyOnly) {
622 assert(Init < ILE->getNumInits() && "should have been expanded");
623 ILE->setInit(Init, BaseInit.getAs<Expr>());
624 }
625 } else if (InitListExpr *InnerILE =
626 dyn_cast<InitListExpr>(ILE->getInit(Init))) {
627 FillInEmptyInitializations(BaseEntity, InnerILE, RequiresSecondPass,
628 ILE, Init, FillWithNoInit);
629 } else if (DesignatedInitUpdateExpr *InnerDIUE =
630 dyn_cast<DesignatedInitUpdateExpr>(ILE->getInit(Init))) {
631 FillInEmptyInitializations(BaseEntity, InnerDIUE->getUpdater(),
632 RequiresSecondPass, ILE, Init,
633 /*FillWithNoInit =*/true);
634 }
635 }
636
FillInEmptyInitForField(unsigned Init,FieldDecl * Field,const InitializedEntity & ParentEntity,InitListExpr * ILE,bool & RequiresSecondPass,bool FillWithNoInit)637 void InitListChecker::FillInEmptyInitForField(unsigned Init, FieldDecl *Field,
638 const InitializedEntity &ParentEntity,
639 InitListExpr *ILE,
640 bool &RequiresSecondPass,
641 bool FillWithNoInit) {
642 SourceLocation Loc = ILE->getEndLoc();
643 unsigned NumInits = ILE->getNumInits();
644 InitializedEntity MemberEntity
645 = InitializedEntity::InitializeMember(Field, &ParentEntity);
646
647 if (Init >= NumInits || !ILE->getInit(Init)) {
648 if (const RecordType *RType = ILE->getType()->getAs<RecordType>())
649 if (!RType->getDecl()->isUnion())
650 assert((Init < NumInits || VerifyOnly) &&
651 "This ILE should have been expanded");
652
653 if (FillWithNoInit) {
654 assert(!VerifyOnly && "should not fill with no-init in verify-only mode");
655 Expr *Filler = new (SemaRef.Context) NoInitExpr(Field->getType());
656 if (Init < NumInits)
657 ILE->setInit(Init, Filler);
658 else
659 ILE->updateInit(SemaRef.Context, Init, Filler);
660 return;
661 }
662 // C++1y [dcl.init.aggr]p7:
663 // If there are fewer initializer-clauses in the list than there are
664 // members in the aggregate, then each member not explicitly initialized
665 // shall be initialized from its brace-or-equal-initializer [...]
666 if (Field->hasInClassInitializer()) {
667 if (VerifyOnly)
668 return;
669
670 ExprResult DIE = SemaRef.BuildCXXDefaultInitExpr(Loc, Field);
671 if (DIE.isInvalid()) {
672 hadError = true;
673 return;
674 }
675 SemaRef.checkInitializerLifetime(MemberEntity, DIE.get());
676 if (Init < NumInits)
677 ILE->setInit(Init, DIE.get());
678 else {
679 ILE->updateInit(SemaRef.Context, Init, DIE.get());
680 RequiresSecondPass = true;
681 }
682 return;
683 }
684
685 if (Field->getType()->isReferenceType()) {
686 if (!VerifyOnly) {
687 // C++ [dcl.init.aggr]p9:
688 // If an incomplete or empty initializer-list leaves a
689 // member of reference type uninitialized, the program is
690 // ill-formed.
691 SemaRef.Diag(Loc, diag::err_init_reference_member_uninitialized)
692 << Field->getType()
693 << ILE->getSyntacticForm()->getSourceRange();
694 SemaRef.Diag(Field->getLocation(),
695 diag::note_uninit_reference_member);
696 }
697 hadError = true;
698 return;
699 }
700
701 ExprResult MemberInit = PerformEmptyInit(Loc, MemberEntity);
702 if (MemberInit.isInvalid()) {
703 hadError = true;
704 return;
705 }
706
707 if (hadError || VerifyOnly) {
708 // Do nothing
709 } else if (Init < NumInits) {
710 ILE->setInit(Init, MemberInit.getAs<Expr>());
711 } else if (!isa<ImplicitValueInitExpr>(MemberInit.get())) {
712 // Empty initialization requires a constructor call, so
713 // extend the initializer list to include the constructor
714 // call and make a note that we'll need to take another pass
715 // through the initializer list.
716 ILE->updateInit(SemaRef.Context, Init, MemberInit.getAs<Expr>());
717 RequiresSecondPass = true;
718 }
719 } else if (InitListExpr *InnerILE
720 = dyn_cast<InitListExpr>(ILE->getInit(Init))) {
721 FillInEmptyInitializations(MemberEntity, InnerILE,
722 RequiresSecondPass, ILE, Init, FillWithNoInit);
723 } else if (DesignatedInitUpdateExpr *InnerDIUE =
724 dyn_cast<DesignatedInitUpdateExpr>(ILE->getInit(Init))) {
725 FillInEmptyInitializations(MemberEntity, InnerDIUE->getUpdater(),
726 RequiresSecondPass, ILE, Init,
727 /*FillWithNoInit =*/true);
728 }
729 }
730
731 /// Recursively replaces NULL values within the given initializer list
732 /// with expressions that perform value-initialization of the
733 /// appropriate type, and finish off the InitListExpr formation.
734 void
FillInEmptyInitializations(const InitializedEntity & Entity,InitListExpr * ILE,bool & RequiresSecondPass,InitListExpr * OuterILE,unsigned OuterIndex,bool FillWithNoInit)735 InitListChecker::FillInEmptyInitializations(const InitializedEntity &Entity,
736 InitListExpr *ILE,
737 bool &RequiresSecondPass,
738 InitListExpr *OuterILE,
739 unsigned OuterIndex,
740 bool FillWithNoInit) {
741 assert((ILE->getType() != SemaRef.Context.VoidTy) &&
742 "Should not have void type");
743
744 // We don't need to do any checks when just filling NoInitExprs; that can't
745 // fail.
746 if (FillWithNoInit && VerifyOnly)
747 return;
748
749 // If this is a nested initializer list, we might have changed its contents
750 // (and therefore some of its properties, such as instantiation-dependence)
751 // while filling it in. Inform the outer initializer list so that its state
752 // can be updated to match.
753 // FIXME: We should fully build the inner initializers before constructing
754 // the outer InitListExpr instead of mutating AST nodes after they have
755 // been used as subexpressions of other nodes.
756 struct UpdateOuterILEWithUpdatedInit {
757 InitListExpr *Outer;
758 unsigned OuterIndex;
759 ~UpdateOuterILEWithUpdatedInit() {
760 if (Outer)
761 Outer->setInit(OuterIndex, Outer->getInit(OuterIndex));
762 }
763 } UpdateOuterRAII = {OuterILE, OuterIndex};
764
765 // A transparent ILE is not performing aggregate initialization and should
766 // not be filled in.
767 if (ILE->isTransparent())
768 return;
769
770 if (const RecordType *RType = ILE->getType()->getAs<RecordType>()) {
771 const RecordDecl *RDecl = RType->getDecl();
772 if (RDecl->isUnion() && ILE->getInitializedFieldInUnion())
773 FillInEmptyInitForField(0, ILE->getInitializedFieldInUnion(),
774 Entity, ILE, RequiresSecondPass, FillWithNoInit);
775 else if (RDecl->isUnion() && isa<CXXRecordDecl>(RDecl) &&
776 cast<CXXRecordDecl>(RDecl)->hasInClassInitializer()) {
777 for (auto *Field : RDecl->fields()) {
778 if (Field->hasInClassInitializer()) {
779 FillInEmptyInitForField(0, Field, Entity, ILE, RequiresSecondPass,
780 FillWithNoInit);
781 break;
782 }
783 }
784 } else {
785 // The fields beyond ILE->getNumInits() are default initialized, so in
786 // order to leave them uninitialized, the ILE is expanded and the extra
787 // fields are then filled with NoInitExpr.
788 unsigned NumElems = numStructUnionElements(ILE->getType());
789 if (RDecl->hasFlexibleArrayMember())
790 ++NumElems;
791 if (!VerifyOnly && ILE->getNumInits() < NumElems)
792 ILE->resizeInits(SemaRef.Context, NumElems);
793
794 unsigned Init = 0;
795
796 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RDecl)) {
797 for (auto &Base : CXXRD->bases()) {
798 if (hadError)
799 return;
800
801 FillInEmptyInitForBase(Init, Base, Entity, ILE, RequiresSecondPass,
802 FillWithNoInit);
803 ++Init;
804 }
805 }
806
807 for (auto *Field : RDecl->fields()) {
808 if (Field->isUnnamedBitfield())
809 continue;
810
811 if (hadError)
812 return;
813
814 FillInEmptyInitForField(Init, Field, Entity, ILE, RequiresSecondPass,
815 FillWithNoInit);
816 if (hadError)
817 return;
818
819 ++Init;
820
821 // Only look at the first initialization of a union.
822 if (RDecl->isUnion())
823 break;
824 }
825 }
826
827 return;
828 }
829
830 QualType ElementType;
831
832 InitializedEntity ElementEntity = Entity;
833 unsigned NumInits = ILE->getNumInits();
834 unsigned NumElements = NumInits;
835 if (const ArrayType *AType = SemaRef.Context.getAsArrayType(ILE->getType())) {
836 ElementType = AType->getElementType();
837 if (const auto *CAType = dyn_cast<ConstantArrayType>(AType))
838 NumElements = CAType->getSize().getZExtValue();
839 // For an array new with an unknown bound, ask for one additional element
840 // in order to populate the array filler.
841 if (Entity.isVariableLengthArrayNew())
842 ++NumElements;
843 ElementEntity = InitializedEntity::InitializeElement(SemaRef.Context,
844 0, Entity);
845 } else if (const VectorType *VType = ILE->getType()->getAs<VectorType>()) {
846 ElementType = VType->getElementType();
847 NumElements = VType->getNumElements();
848 ElementEntity = InitializedEntity::InitializeElement(SemaRef.Context,
849 0, Entity);
850 } else
851 ElementType = ILE->getType();
852
853 bool SkipEmptyInitChecks = false;
854 for (unsigned Init = 0; Init != NumElements; ++Init) {
855 if (hadError)
856 return;
857
858 if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement ||
859 ElementEntity.getKind() == InitializedEntity::EK_VectorElement)
860 ElementEntity.setElementIndex(Init);
861
862 if (Init >= NumInits && (ILE->hasArrayFiller() || SkipEmptyInitChecks))
863 return;
864
865 Expr *InitExpr = (Init < NumInits ? ILE->getInit(Init) : nullptr);
866 if (!InitExpr && Init < NumInits && ILE->hasArrayFiller())
867 ILE->setInit(Init, ILE->getArrayFiller());
868 else if (!InitExpr && !ILE->hasArrayFiller()) {
869 // In VerifyOnly mode, there's no point performing empty initialization
870 // more than once.
871 if (SkipEmptyInitChecks)
872 continue;
873
874 Expr *Filler = nullptr;
875
876 if (FillWithNoInit)
877 Filler = new (SemaRef.Context) NoInitExpr(ElementType);
878 else {
879 ExprResult ElementInit =
880 PerformEmptyInit(ILE->getEndLoc(), ElementEntity);
881 if (ElementInit.isInvalid()) {
882 hadError = true;
883 return;
884 }
885
886 Filler = ElementInit.getAs<Expr>();
887 }
888
889 if (hadError) {
890 // Do nothing
891 } else if (VerifyOnly) {
892 SkipEmptyInitChecks = true;
893 } else if (Init < NumInits) {
894 // For arrays, just set the expression used for value-initialization
895 // of the "holes" in the array.
896 if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement)
897 ILE->setArrayFiller(Filler);
898 else
899 ILE->setInit(Init, Filler);
900 } else {
901 // For arrays, just set the expression used for value-initialization
902 // of the rest of elements and exit.
903 if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement) {
904 ILE->setArrayFiller(Filler);
905 return;
906 }
907
908 if (!isa<ImplicitValueInitExpr>(Filler) && !isa<NoInitExpr>(Filler)) {
909 // Empty initialization requires a constructor call, so
910 // extend the initializer list to include the constructor
911 // call and make a note that we'll need to take another pass
912 // through the initializer list.
913 ILE->updateInit(SemaRef.Context, Init, Filler);
914 RequiresSecondPass = true;
915 }
916 }
917 } else if (InitListExpr *InnerILE
918 = dyn_cast_or_null<InitListExpr>(InitExpr)) {
919 FillInEmptyInitializations(ElementEntity, InnerILE, RequiresSecondPass,
920 ILE, Init, FillWithNoInit);
921 } else if (DesignatedInitUpdateExpr *InnerDIUE =
922 dyn_cast_or_null<DesignatedInitUpdateExpr>(InitExpr)) {
923 FillInEmptyInitializations(ElementEntity, InnerDIUE->getUpdater(),
924 RequiresSecondPass, ILE, Init,
925 /*FillWithNoInit =*/true);
926 }
927 }
928 }
929
hasAnyDesignatedInits(const InitListExpr * IL)930 static bool hasAnyDesignatedInits(const InitListExpr *IL) {
931 for (const Stmt *Init : *IL)
932 if (Init && isa<DesignatedInitExpr>(Init))
933 return true;
934 return false;
935 }
936
InitListChecker(Sema & S,const InitializedEntity & Entity,InitListExpr * IL,QualType & T,bool VerifyOnly,bool TreatUnavailableAsInvalid,bool InOverloadResolution)937 InitListChecker::InitListChecker(Sema &S, const InitializedEntity &Entity,
938 InitListExpr *IL, QualType &T, bool VerifyOnly,
939 bool TreatUnavailableAsInvalid,
940 bool InOverloadResolution)
941 : SemaRef(S), VerifyOnly(VerifyOnly),
942 TreatUnavailableAsInvalid(TreatUnavailableAsInvalid),
943 InOverloadResolution(InOverloadResolution) {
944 if (!VerifyOnly || hasAnyDesignatedInits(IL)) {
945 FullyStructuredList =
946 createInitListExpr(T, IL->getSourceRange(), IL->getNumInits());
947
948 // FIXME: Check that IL isn't already the semantic form of some other
949 // InitListExpr. If it is, we'd create a broken AST.
950 if (!VerifyOnly)
951 FullyStructuredList->setSyntacticForm(IL);
952 }
953
954 CheckExplicitInitList(Entity, IL, T, FullyStructuredList,
955 /*TopLevelObject=*/true);
956
957 if (!hadError && FullyStructuredList) {
958 bool RequiresSecondPass = false;
959 FillInEmptyInitializations(Entity, FullyStructuredList, RequiresSecondPass,
960 /*OuterILE=*/nullptr, /*OuterIndex=*/0);
961 if (RequiresSecondPass && !hadError)
962 FillInEmptyInitializations(Entity, FullyStructuredList,
963 RequiresSecondPass, nullptr, 0);
964 }
965 }
966
numArrayElements(QualType DeclType)967 int InitListChecker::numArrayElements(QualType DeclType) {
968 // FIXME: use a proper constant
969 int maxElements = 0x7FFFFFFF;
970 if (const ConstantArrayType *CAT =
971 SemaRef.Context.getAsConstantArrayType(DeclType)) {
972 maxElements = static_cast<int>(CAT->getSize().getZExtValue());
973 }
974 return maxElements;
975 }
976
numStructUnionElements(QualType DeclType)977 int InitListChecker::numStructUnionElements(QualType DeclType) {
978 RecordDecl *structDecl = DeclType->castAs<RecordType>()->getDecl();
979 int InitializableMembers = 0;
980 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(structDecl))
981 InitializableMembers += CXXRD->getNumBases();
982 for (const auto *Field : structDecl->fields())
983 if (!Field->isUnnamedBitfield())
984 ++InitializableMembers;
985
986 if (structDecl->isUnion())
987 return std::min(InitializableMembers, 1);
988 return InitializableMembers - structDecl->hasFlexibleArrayMember();
989 }
990
991 /// Determine whether Entity is an entity for which it is idiomatic to elide
992 /// the braces in aggregate initialization.
isIdiomaticBraceElisionEntity(const InitializedEntity & Entity)993 static bool isIdiomaticBraceElisionEntity(const InitializedEntity &Entity) {
994 // Recursive initialization of the one and only field within an aggregate
995 // class is considered idiomatic. This case arises in particular for
996 // initialization of std::array, where the C++ standard suggests the idiom of
997 //
998 // std::array<T, N> arr = {1, 2, 3};
999 //
1000 // (where std::array is an aggregate struct containing a single array field.
1001
1002 // FIXME: Should aggregate initialization of a struct with a single
1003 // base class and no members also suppress the warning?
1004 if (Entity.getKind() != InitializedEntity::EK_Member || !Entity.getParent())
1005 return false;
1006
1007 auto *ParentRD =
1008 Entity.getParent()->getType()->castAs<RecordType>()->getDecl();
1009 if (CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(ParentRD))
1010 if (CXXRD->getNumBases())
1011 return false;
1012
1013 auto FieldIt = ParentRD->field_begin();
1014 assert(FieldIt != ParentRD->field_end() &&
1015 "no fields but have initializer for member?");
1016 return ++FieldIt == ParentRD->field_end();
1017 }
1018
1019 /// Check whether the range of the initializer \p ParentIList from element
1020 /// \p Index onwards can be used to initialize an object of type \p T. Update
1021 /// \p Index to indicate how many elements of the list were consumed.
1022 ///
1023 /// This also fills in \p StructuredList, from element \p StructuredIndex
1024 /// onwards, with the fully-braced, desugared form of the initialization.
CheckImplicitInitList(const InitializedEntity & Entity,InitListExpr * ParentIList,QualType T,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1025 void InitListChecker::CheckImplicitInitList(const InitializedEntity &Entity,
1026 InitListExpr *ParentIList,
1027 QualType T, unsigned &Index,
1028 InitListExpr *StructuredList,
1029 unsigned &StructuredIndex) {
1030 int maxElements = 0;
1031
1032 if (T->isArrayType())
1033 maxElements = numArrayElements(T);
1034 else if (T->isRecordType())
1035 maxElements = numStructUnionElements(T);
1036 else if (T->isVectorType())
1037 maxElements = T->castAs<VectorType>()->getNumElements();
1038 else
1039 llvm_unreachable("CheckImplicitInitList(): Illegal type");
1040
1041 if (maxElements == 0) {
1042 if (!VerifyOnly)
1043 SemaRef.Diag(ParentIList->getInit(Index)->getBeginLoc(),
1044 diag::err_implicit_empty_initializer);
1045 ++Index;
1046 hadError = true;
1047 return;
1048 }
1049
1050 // Build a structured initializer list corresponding to this subobject.
1051 InitListExpr *StructuredSubobjectInitList = getStructuredSubobjectInit(
1052 ParentIList, Index, T, StructuredList, StructuredIndex,
1053 SourceRange(ParentIList->getInit(Index)->getBeginLoc(),
1054 ParentIList->getSourceRange().getEnd()));
1055 unsigned StructuredSubobjectInitIndex = 0;
1056
1057 // Check the element types and build the structural subobject.
1058 unsigned StartIndex = Index;
1059 CheckListElementTypes(Entity, ParentIList, T,
1060 /*SubobjectIsDesignatorContext=*/false, Index,
1061 StructuredSubobjectInitList,
1062 StructuredSubobjectInitIndex);
1063
1064 if (StructuredSubobjectInitList) {
1065 StructuredSubobjectInitList->setType(T);
1066
1067 unsigned EndIndex = (Index == StartIndex? StartIndex : Index - 1);
1068 // Update the structured sub-object initializer so that it's ending
1069 // range corresponds with the end of the last initializer it used.
1070 if (EndIndex < ParentIList->getNumInits() &&
1071 ParentIList->getInit(EndIndex)) {
1072 SourceLocation EndLoc
1073 = ParentIList->getInit(EndIndex)->getSourceRange().getEnd();
1074 StructuredSubobjectInitList->setRBraceLoc(EndLoc);
1075 }
1076
1077 // Complain about missing braces.
1078 if (!VerifyOnly && (T->isArrayType() || T->isRecordType()) &&
1079 !ParentIList->isIdiomaticZeroInitializer(SemaRef.getLangOpts()) &&
1080 !isIdiomaticBraceElisionEntity(Entity)) {
1081 SemaRef.Diag(StructuredSubobjectInitList->getBeginLoc(),
1082 diag::warn_missing_braces)
1083 << StructuredSubobjectInitList->getSourceRange()
1084 << FixItHint::CreateInsertion(
1085 StructuredSubobjectInitList->getBeginLoc(), "{")
1086 << FixItHint::CreateInsertion(
1087 SemaRef.getLocForEndOfToken(
1088 StructuredSubobjectInitList->getEndLoc()),
1089 "}");
1090 }
1091
1092 // Warn if this type won't be an aggregate in future versions of C++.
1093 auto *CXXRD = T->getAsCXXRecordDecl();
1094 if (!VerifyOnly && CXXRD && CXXRD->hasUserDeclaredConstructor()) {
1095 SemaRef.Diag(StructuredSubobjectInitList->getBeginLoc(),
1096 diag::warn_cxx20_compat_aggregate_init_with_ctors)
1097 << StructuredSubobjectInitList->getSourceRange() << T;
1098 }
1099 }
1100 }
1101
1102 /// Warn that \p Entity was of scalar type and was initialized by a
1103 /// single-element braced initializer list.
warnBracedScalarInit(Sema & S,const InitializedEntity & Entity,SourceRange Braces)1104 static void warnBracedScalarInit(Sema &S, const InitializedEntity &Entity,
1105 SourceRange Braces) {
1106 // Don't warn during template instantiation. If the initialization was
1107 // non-dependent, we warned during the initial parse; otherwise, the
1108 // type might not be scalar in some uses of the template.
1109 if (S.inTemplateInstantiation())
1110 return;
1111
1112 unsigned DiagID = 0;
1113
1114 switch (Entity.getKind()) {
1115 case InitializedEntity::EK_VectorElement:
1116 case InitializedEntity::EK_ComplexElement:
1117 case InitializedEntity::EK_ArrayElement:
1118 case InitializedEntity::EK_Parameter:
1119 case InitializedEntity::EK_Parameter_CF_Audited:
1120 case InitializedEntity::EK_Result:
1121 // Extra braces here are suspicious.
1122 DiagID = diag::warn_braces_around_init;
1123 break;
1124
1125 case InitializedEntity::EK_Member:
1126 // Warn on aggregate initialization but not on ctor init list or
1127 // default member initializer.
1128 if (Entity.getParent())
1129 DiagID = diag::warn_braces_around_init;
1130 break;
1131
1132 case InitializedEntity::EK_Variable:
1133 case InitializedEntity::EK_LambdaCapture:
1134 // No warning, might be direct-list-initialization.
1135 // FIXME: Should we warn for copy-list-initialization in these cases?
1136 break;
1137
1138 case InitializedEntity::EK_New:
1139 case InitializedEntity::EK_Temporary:
1140 case InitializedEntity::EK_CompoundLiteralInit:
1141 // No warning, braces are part of the syntax of the underlying construct.
1142 break;
1143
1144 case InitializedEntity::EK_RelatedResult:
1145 // No warning, we already warned when initializing the result.
1146 break;
1147
1148 case InitializedEntity::EK_Exception:
1149 case InitializedEntity::EK_Base:
1150 case InitializedEntity::EK_Delegating:
1151 case InitializedEntity::EK_BlockElement:
1152 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
1153 case InitializedEntity::EK_Binding:
1154 case InitializedEntity::EK_StmtExprResult:
1155 llvm_unreachable("unexpected braced scalar init");
1156 }
1157
1158 if (DiagID) {
1159 S.Diag(Braces.getBegin(), DiagID)
1160 << Entity.getType()->isSizelessBuiltinType() << Braces
1161 << FixItHint::CreateRemoval(Braces.getBegin())
1162 << FixItHint::CreateRemoval(Braces.getEnd());
1163 }
1164 }
1165
1166 /// Check whether the initializer \p IList (that was written with explicit
1167 /// braces) can be used to initialize an object of type \p T.
1168 ///
1169 /// This also fills in \p StructuredList with the fully-braced, desugared
1170 /// form of the initialization.
CheckExplicitInitList(const InitializedEntity & Entity,InitListExpr * IList,QualType & T,InitListExpr * StructuredList,bool TopLevelObject)1171 void InitListChecker::CheckExplicitInitList(const InitializedEntity &Entity,
1172 InitListExpr *IList, QualType &T,
1173 InitListExpr *StructuredList,
1174 bool TopLevelObject) {
1175 unsigned Index = 0, StructuredIndex = 0;
1176 CheckListElementTypes(Entity, IList, T, /*SubobjectIsDesignatorContext=*/true,
1177 Index, StructuredList, StructuredIndex, TopLevelObject);
1178 if (StructuredList) {
1179 QualType ExprTy = T;
1180 if (!ExprTy->isArrayType())
1181 ExprTy = ExprTy.getNonLValueExprType(SemaRef.Context);
1182 if (!VerifyOnly)
1183 IList->setType(ExprTy);
1184 StructuredList->setType(ExprTy);
1185 }
1186 if (hadError)
1187 return;
1188
1189 // Don't complain for incomplete types, since we'll get an error elsewhere.
1190 if (Index < IList->getNumInits() && !T->isIncompleteType()) {
1191 // We have leftover initializers
1192 bool ExtraInitsIsError = SemaRef.getLangOpts().CPlusPlus ||
1193 (SemaRef.getLangOpts().OpenCL && T->isVectorType());
1194 hadError = ExtraInitsIsError;
1195 if (VerifyOnly) {
1196 return;
1197 } else if (StructuredIndex == 1 &&
1198 IsStringInit(StructuredList->getInit(0), T, SemaRef.Context) ==
1199 SIF_None) {
1200 unsigned DK =
1201 ExtraInitsIsError
1202 ? diag::err_excess_initializers_in_char_array_initializer
1203 : diag::ext_excess_initializers_in_char_array_initializer;
1204 SemaRef.Diag(IList->getInit(Index)->getBeginLoc(), DK)
1205 << IList->getInit(Index)->getSourceRange();
1206 } else if (T->isSizelessBuiltinType()) {
1207 unsigned DK = ExtraInitsIsError
1208 ? diag::err_excess_initializers_for_sizeless_type
1209 : diag::ext_excess_initializers_for_sizeless_type;
1210 SemaRef.Diag(IList->getInit(Index)->getBeginLoc(), DK)
1211 << T << IList->getInit(Index)->getSourceRange();
1212 } else {
1213 int initKind = T->isArrayType() ? 0 :
1214 T->isVectorType() ? 1 :
1215 T->isScalarType() ? 2 :
1216 T->isUnionType() ? 3 :
1217 4;
1218
1219 unsigned DK = ExtraInitsIsError ? diag::err_excess_initializers
1220 : diag::ext_excess_initializers;
1221 SemaRef.Diag(IList->getInit(Index)->getBeginLoc(), DK)
1222 << initKind << IList->getInit(Index)->getSourceRange();
1223 }
1224 }
1225
1226 if (!VerifyOnly) {
1227 if (T->isScalarType() && IList->getNumInits() == 1 &&
1228 !isa<InitListExpr>(IList->getInit(0)))
1229 warnBracedScalarInit(SemaRef, Entity, IList->getSourceRange());
1230
1231 // Warn if this is a class type that won't be an aggregate in future
1232 // versions of C++.
1233 auto *CXXRD = T->getAsCXXRecordDecl();
1234 if (CXXRD && CXXRD->hasUserDeclaredConstructor()) {
1235 // Don't warn if there's an equivalent default constructor that would be
1236 // used instead.
1237 bool HasEquivCtor = false;
1238 if (IList->getNumInits() == 0) {
1239 auto *CD = SemaRef.LookupDefaultConstructor(CXXRD);
1240 HasEquivCtor = CD && !CD->isDeleted();
1241 }
1242
1243 if (!HasEquivCtor) {
1244 SemaRef.Diag(IList->getBeginLoc(),
1245 diag::warn_cxx20_compat_aggregate_init_with_ctors)
1246 << IList->getSourceRange() << T;
1247 }
1248 }
1249 }
1250 }
1251
CheckListElementTypes(const InitializedEntity & Entity,InitListExpr * IList,QualType & DeclType,bool SubobjectIsDesignatorContext,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex,bool TopLevelObject)1252 void InitListChecker::CheckListElementTypes(const InitializedEntity &Entity,
1253 InitListExpr *IList,
1254 QualType &DeclType,
1255 bool SubobjectIsDesignatorContext,
1256 unsigned &Index,
1257 InitListExpr *StructuredList,
1258 unsigned &StructuredIndex,
1259 bool TopLevelObject) {
1260 if (DeclType->isAnyComplexType() && SubobjectIsDesignatorContext) {
1261 // Explicitly braced initializer for complex type can be real+imaginary
1262 // parts.
1263 CheckComplexType(Entity, IList, DeclType, Index,
1264 StructuredList, StructuredIndex);
1265 } else if (DeclType->isScalarType()) {
1266 CheckScalarType(Entity, IList, DeclType, Index,
1267 StructuredList, StructuredIndex);
1268 } else if (DeclType->isVectorType()) {
1269 CheckVectorType(Entity, IList, DeclType, Index,
1270 StructuredList, StructuredIndex);
1271 } else if (DeclType->isRecordType()) {
1272 assert(DeclType->isAggregateType() &&
1273 "non-aggregate records should be handed in CheckSubElementType");
1274 RecordDecl *RD = DeclType->castAs<RecordType>()->getDecl();
1275 auto Bases =
1276 CXXRecordDecl::base_class_range(CXXRecordDecl::base_class_iterator(),
1277 CXXRecordDecl::base_class_iterator());
1278 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
1279 Bases = CXXRD->bases();
1280 CheckStructUnionTypes(Entity, IList, DeclType, Bases, RD->field_begin(),
1281 SubobjectIsDesignatorContext, Index, StructuredList,
1282 StructuredIndex, TopLevelObject);
1283 } else if (DeclType->isArrayType()) {
1284 llvm::APSInt Zero(
1285 SemaRef.Context.getTypeSize(SemaRef.Context.getSizeType()),
1286 false);
1287 CheckArrayType(Entity, IList, DeclType, Zero,
1288 SubobjectIsDesignatorContext, Index,
1289 StructuredList, StructuredIndex);
1290 } else if (DeclType->isVoidType() || DeclType->isFunctionType()) {
1291 // This type is invalid, issue a diagnostic.
1292 ++Index;
1293 if (!VerifyOnly)
1294 SemaRef.Diag(IList->getBeginLoc(), diag::err_illegal_initializer_type)
1295 << DeclType;
1296 hadError = true;
1297 } else if (DeclType->isReferenceType()) {
1298 CheckReferenceType(Entity, IList, DeclType, Index,
1299 StructuredList, StructuredIndex);
1300 } else if (DeclType->isObjCObjectType()) {
1301 if (!VerifyOnly)
1302 SemaRef.Diag(IList->getBeginLoc(), diag::err_init_objc_class) << DeclType;
1303 hadError = true;
1304 } else if (DeclType->isOCLIntelSubgroupAVCType() ||
1305 DeclType->isSizelessBuiltinType()) {
1306 // Checks for scalar type are sufficient for these types too.
1307 CheckScalarType(Entity, IList, DeclType, Index, StructuredList,
1308 StructuredIndex);
1309 } else {
1310 if (!VerifyOnly)
1311 SemaRef.Diag(IList->getBeginLoc(), diag::err_illegal_initializer_type)
1312 << DeclType;
1313 hadError = true;
1314 }
1315 }
1316
CheckSubElementType(const InitializedEntity & Entity,InitListExpr * IList,QualType ElemType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1317 void InitListChecker::CheckSubElementType(const InitializedEntity &Entity,
1318 InitListExpr *IList,
1319 QualType ElemType,
1320 unsigned &Index,
1321 InitListExpr *StructuredList,
1322 unsigned &StructuredIndex) {
1323 Expr *expr = IList->getInit(Index);
1324
1325 if (ElemType->isReferenceType())
1326 return CheckReferenceType(Entity, IList, ElemType, Index,
1327 StructuredList, StructuredIndex);
1328
1329 if (InitListExpr *SubInitList = dyn_cast<InitListExpr>(expr)) {
1330 if (SubInitList->getNumInits() == 1 &&
1331 IsStringInit(SubInitList->getInit(0), ElemType, SemaRef.Context) ==
1332 SIF_None) {
1333 // FIXME: It would be more faithful and no less correct to include an
1334 // InitListExpr in the semantic form of the initializer list in this case.
1335 expr = SubInitList->getInit(0);
1336 }
1337 // Nested aggregate initialization and C++ initialization are handled later.
1338 } else if (isa<ImplicitValueInitExpr>(expr)) {
1339 // This happens during template instantiation when we see an InitListExpr
1340 // that we've already checked once.
1341 assert(SemaRef.Context.hasSameType(expr->getType(), ElemType) &&
1342 "found implicit initialization for the wrong type");
1343 UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
1344 ++Index;
1345 return;
1346 }
1347
1348 if (SemaRef.getLangOpts().CPlusPlus || isa<InitListExpr>(expr)) {
1349 // C++ [dcl.init.aggr]p2:
1350 // Each member is copy-initialized from the corresponding
1351 // initializer-clause.
1352
1353 // FIXME: Better EqualLoc?
1354 InitializationKind Kind =
1355 InitializationKind::CreateCopy(expr->getBeginLoc(), SourceLocation());
1356
1357 // Vector elements can be initialized from other vectors in which case
1358 // we need initialization entity with a type of a vector (and not a vector
1359 // element!) initializing multiple vector elements.
1360 auto TmpEntity =
1361 (ElemType->isExtVectorType() && !Entity.getType()->isExtVectorType())
1362 ? InitializedEntity::InitializeTemporary(ElemType)
1363 : Entity;
1364
1365 InitializationSequence Seq(SemaRef, TmpEntity, Kind, expr,
1366 /*TopLevelOfInitList*/ true);
1367
1368 // C++14 [dcl.init.aggr]p13:
1369 // If the assignment-expression can initialize a member, the member is
1370 // initialized. Otherwise [...] brace elision is assumed
1371 //
1372 // Brace elision is never performed if the element is not an
1373 // assignment-expression.
1374 if (Seq || isa<InitListExpr>(expr)) {
1375 if (!VerifyOnly) {
1376 ExprResult Result = Seq.Perform(SemaRef, TmpEntity, Kind, expr);
1377 if (Result.isInvalid())
1378 hadError = true;
1379
1380 UpdateStructuredListElement(StructuredList, StructuredIndex,
1381 Result.getAs<Expr>());
1382 } else if (!Seq) {
1383 hadError = true;
1384 } else if (StructuredList) {
1385 UpdateStructuredListElement(StructuredList, StructuredIndex,
1386 getDummyInit());
1387 }
1388 ++Index;
1389 return;
1390 }
1391
1392 // Fall through for subaggregate initialization
1393 } else if (ElemType->isScalarType() || ElemType->isAtomicType()) {
1394 // FIXME: Need to handle atomic aggregate types with implicit init lists.
1395 return CheckScalarType(Entity, IList, ElemType, Index,
1396 StructuredList, StructuredIndex);
1397 } else if (const ArrayType *arrayType =
1398 SemaRef.Context.getAsArrayType(ElemType)) {
1399 // arrayType can be incomplete if we're initializing a flexible
1400 // array member. There's nothing we can do with the completed
1401 // type here, though.
1402
1403 if (IsStringInit(expr, arrayType, SemaRef.Context) == SIF_None) {
1404 // FIXME: Should we do this checking in verify-only mode?
1405 if (!VerifyOnly)
1406 CheckStringInit(expr, ElemType, arrayType, SemaRef);
1407 if (StructuredList)
1408 UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
1409 ++Index;
1410 return;
1411 }
1412
1413 // Fall through for subaggregate initialization.
1414
1415 } else {
1416 assert((ElemType->isRecordType() || ElemType->isVectorType() ||
1417 ElemType->isOpenCLSpecificType()) && "Unexpected type");
1418
1419 // C99 6.7.8p13:
1420 //
1421 // The initializer for a structure or union object that has
1422 // automatic storage duration shall be either an initializer
1423 // list as described below, or a single expression that has
1424 // compatible structure or union type. In the latter case, the
1425 // initial value of the object, including unnamed members, is
1426 // that of the expression.
1427 ExprResult ExprRes = expr;
1428 if (SemaRef.CheckSingleAssignmentConstraints(
1429 ElemType, ExprRes, !VerifyOnly) != Sema::Incompatible) {
1430 if (ExprRes.isInvalid())
1431 hadError = true;
1432 else {
1433 ExprRes = SemaRef.DefaultFunctionArrayLvalueConversion(ExprRes.get());
1434 if (ExprRes.isInvalid())
1435 hadError = true;
1436 }
1437 UpdateStructuredListElement(StructuredList, StructuredIndex,
1438 ExprRes.getAs<Expr>());
1439 ++Index;
1440 return;
1441 }
1442 ExprRes.get();
1443 // Fall through for subaggregate initialization
1444 }
1445
1446 // C++ [dcl.init.aggr]p12:
1447 //
1448 // [...] Otherwise, if the member is itself a non-empty
1449 // subaggregate, brace elision is assumed and the initializer is
1450 // considered for the initialization of the first member of
1451 // the subaggregate.
1452 // OpenCL vector initializer is handled elsewhere.
1453 if ((!SemaRef.getLangOpts().OpenCL && ElemType->isVectorType()) ||
1454 ElemType->isAggregateType()) {
1455 CheckImplicitInitList(Entity, IList, ElemType, Index, StructuredList,
1456 StructuredIndex);
1457 ++StructuredIndex;
1458 } else {
1459 if (!VerifyOnly) {
1460 // We cannot initialize this element, so let PerformCopyInitialization
1461 // produce the appropriate diagnostic. We already checked that this
1462 // initialization will fail.
1463 ExprResult Copy =
1464 SemaRef.PerformCopyInitialization(Entity, SourceLocation(), expr,
1465 /*TopLevelOfInitList=*/true);
1466 (void)Copy;
1467 assert(Copy.isInvalid() &&
1468 "expected non-aggregate initialization to fail");
1469 }
1470 hadError = true;
1471 ++Index;
1472 ++StructuredIndex;
1473 }
1474 }
1475
CheckComplexType(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1476 void InitListChecker::CheckComplexType(const InitializedEntity &Entity,
1477 InitListExpr *IList, QualType DeclType,
1478 unsigned &Index,
1479 InitListExpr *StructuredList,
1480 unsigned &StructuredIndex) {
1481 assert(Index == 0 && "Index in explicit init list must be zero");
1482
1483 // As an extension, clang supports complex initializers, which initialize
1484 // a complex number component-wise. When an explicit initializer list for
1485 // a complex number contains two two initializers, this extension kicks in:
1486 // it exepcts the initializer list to contain two elements convertible to
1487 // the element type of the complex type. The first element initializes
1488 // the real part, and the second element intitializes the imaginary part.
1489
1490 if (IList->getNumInits() != 2)
1491 return CheckScalarType(Entity, IList, DeclType, Index, StructuredList,
1492 StructuredIndex);
1493
1494 // This is an extension in C. (The builtin _Complex type does not exist
1495 // in the C++ standard.)
1496 if (!SemaRef.getLangOpts().CPlusPlus && !VerifyOnly)
1497 SemaRef.Diag(IList->getBeginLoc(), diag::ext_complex_component_init)
1498 << IList->getSourceRange();
1499
1500 // Initialize the complex number.
1501 QualType elementType = DeclType->castAs<ComplexType>()->getElementType();
1502 InitializedEntity ElementEntity =
1503 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
1504
1505 for (unsigned i = 0; i < 2; ++i) {
1506 ElementEntity.setElementIndex(Index);
1507 CheckSubElementType(ElementEntity, IList, elementType, Index,
1508 StructuredList, StructuredIndex);
1509 }
1510 }
1511
CheckScalarType(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1512 void InitListChecker::CheckScalarType(const InitializedEntity &Entity,
1513 InitListExpr *IList, QualType DeclType,
1514 unsigned &Index,
1515 InitListExpr *StructuredList,
1516 unsigned &StructuredIndex) {
1517 if (Index >= IList->getNumInits()) {
1518 if (!VerifyOnly) {
1519 if (DeclType->isSizelessBuiltinType())
1520 SemaRef.Diag(IList->getBeginLoc(),
1521 SemaRef.getLangOpts().CPlusPlus11
1522 ? diag::warn_cxx98_compat_empty_sizeless_initializer
1523 : diag::err_empty_sizeless_initializer)
1524 << DeclType << IList->getSourceRange();
1525 else
1526 SemaRef.Diag(IList->getBeginLoc(),
1527 SemaRef.getLangOpts().CPlusPlus11
1528 ? diag::warn_cxx98_compat_empty_scalar_initializer
1529 : diag::err_empty_scalar_initializer)
1530 << IList->getSourceRange();
1531 }
1532 hadError = !SemaRef.getLangOpts().CPlusPlus11;
1533 ++Index;
1534 ++StructuredIndex;
1535 return;
1536 }
1537
1538 Expr *expr = IList->getInit(Index);
1539 if (InitListExpr *SubIList = dyn_cast<InitListExpr>(expr)) {
1540 // FIXME: This is invalid, and accepting it causes overload resolution
1541 // to pick the wrong overload in some corner cases.
1542 if (!VerifyOnly)
1543 SemaRef.Diag(SubIList->getBeginLoc(), diag::ext_many_braces_around_init)
1544 << DeclType->isSizelessBuiltinType() << SubIList->getSourceRange();
1545
1546 CheckScalarType(Entity, SubIList, DeclType, Index, StructuredList,
1547 StructuredIndex);
1548 return;
1549 } else if (isa<DesignatedInitExpr>(expr)) {
1550 if (!VerifyOnly)
1551 SemaRef.Diag(expr->getBeginLoc(),
1552 diag::err_designator_for_scalar_or_sizeless_init)
1553 << DeclType->isSizelessBuiltinType() << DeclType
1554 << expr->getSourceRange();
1555 hadError = true;
1556 ++Index;
1557 ++StructuredIndex;
1558 return;
1559 }
1560
1561 ExprResult Result;
1562 if (VerifyOnly) {
1563 if (SemaRef.CanPerformCopyInitialization(Entity, expr))
1564 Result = getDummyInit();
1565 else
1566 Result = ExprError();
1567 } else {
1568 Result =
1569 SemaRef.PerformCopyInitialization(Entity, expr->getBeginLoc(), expr,
1570 /*TopLevelOfInitList=*/true);
1571 }
1572
1573 Expr *ResultExpr = nullptr;
1574
1575 if (Result.isInvalid())
1576 hadError = true; // types weren't compatible.
1577 else {
1578 ResultExpr = Result.getAs<Expr>();
1579
1580 if (ResultExpr != expr && !VerifyOnly) {
1581 // The type was promoted, update initializer list.
1582 // FIXME: Why are we updating the syntactic init list?
1583 IList->setInit(Index, ResultExpr);
1584 }
1585 }
1586 if (hadError)
1587 ++StructuredIndex;
1588 else
1589 UpdateStructuredListElement(StructuredList, StructuredIndex, ResultExpr);
1590 ++Index;
1591 }
1592
CheckReferenceType(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1593 void InitListChecker::CheckReferenceType(const InitializedEntity &Entity,
1594 InitListExpr *IList, QualType DeclType,
1595 unsigned &Index,
1596 InitListExpr *StructuredList,
1597 unsigned &StructuredIndex) {
1598 if (Index >= IList->getNumInits()) {
1599 // FIXME: It would be wonderful if we could point at the actual member. In
1600 // general, it would be useful to pass location information down the stack,
1601 // so that we know the location (or decl) of the "current object" being
1602 // initialized.
1603 if (!VerifyOnly)
1604 SemaRef.Diag(IList->getBeginLoc(),
1605 diag::err_init_reference_member_uninitialized)
1606 << DeclType << IList->getSourceRange();
1607 hadError = true;
1608 ++Index;
1609 ++StructuredIndex;
1610 return;
1611 }
1612
1613 Expr *expr = IList->getInit(Index);
1614 if (isa<InitListExpr>(expr) && !SemaRef.getLangOpts().CPlusPlus11) {
1615 if (!VerifyOnly)
1616 SemaRef.Diag(IList->getBeginLoc(), diag::err_init_non_aggr_init_list)
1617 << DeclType << IList->getSourceRange();
1618 hadError = true;
1619 ++Index;
1620 ++StructuredIndex;
1621 return;
1622 }
1623
1624 ExprResult Result;
1625 if (VerifyOnly) {
1626 if (SemaRef.CanPerformCopyInitialization(Entity,expr))
1627 Result = getDummyInit();
1628 else
1629 Result = ExprError();
1630 } else {
1631 Result =
1632 SemaRef.PerformCopyInitialization(Entity, expr->getBeginLoc(), expr,
1633 /*TopLevelOfInitList=*/true);
1634 }
1635
1636 if (Result.isInvalid())
1637 hadError = true;
1638
1639 expr = Result.getAs<Expr>();
1640 // FIXME: Why are we updating the syntactic init list?
1641 if (!VerifyOnly && expr)
1642 IList->setInit(Index, expr);
1643
1644 if (hadError)
1645 ++StructuredIndex;
1646 else
1647 UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
1648 ++Index;
1649 }
1650
CheckVectorType(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1651 void InitListChecker::CheckVectorType(const InitializedEntity &Entity,
1652 InitListExpr *IList, QualType DeclType,
1653 unsigned &Index,
1654 InitListExpr *StructuredList,
1655 unsigned &StructuredIndex) {
1656 const VectorType *VT = DeclType->castAs<VectorType>();
1657 unsigned maxElements = VT->getNumElements();
1658 unsigned numEltsInit = 0;
1659 QualType elementType = VT->getElementType();
1660
1661 if (Index >= IList->getNumInits()) {
1662 // Make sure the element type can be value-initialized.
1663 CheckEmptyInitializable(
1664 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity),
1665 IList->getEndLoc());
1666 return;
1667 }
1668
1669 if (!SemaRef.getLangOpts().OpenCL) {
1670 // If the initializing element is a vector, try to copy-initialize
1671 // instead of breaking it apart (which is doomed to failure anyway).
1672 Expr *Init = IList->getInit(Index);
1673 if (!isa<InitListExpr>(Init) && Init->getType()->isVectorType()) {
1674 ExprResult Result;
1675 if (VerifyOnly) {
1676 if (SemaRef.CanPerformCopyInitialization(Entity, Init))
1677 Result = getDummyInit();
1678 else
1679 Result = ExprError();
1680 } else {
1681 Result =
1682 SemaRef.PerformCopyInitialization(Entity, Init->getBeginLoc(), Init,
1683 /*TopLevelOfInitList=*/true);
1684 }
1685
1686 Expr *ResultExpr = nullptr;
1687 if (Result.isInvalid())
1688 hadError = true; // types weren't compatible.
1689 else {
1690 ResultExpr = Result.getAs<Expr>();
1691
1692 if (ResultExpr != Init && !VerifyOnly) {
1693 // The type was promoted, update initializer list.
1694 // FIXME: Why are we updating the syntactic init list?
1695 IList->setInit(Index, ResultExpr);
1696 }
1697 }
1698 if (hadError)
1699 ++StructuredIndex;
1700 else
1701 UpdateStructuredListElement(StructuredList, StructuredIndex,
1702 ResultExpr);
1703 ++Index;
1704 return;
1705 }
1706
1707 InitializedEntity ElementEntity =
1708 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
1709
1710 for (unsigned i = 0; i < maxElements; ++i, ++numEltsInit) {
1711 // Don't attempt to go past the end of the init list
1712 if (Index >= IList->getNumInits()) {
1713 CheckEmptyInitializable(ElementEntity, IList->getEndLoc());
1714 break;
1715 }
1716
1717 ElementEntity.setElementIndex(Index);
1718 CheckSubElementType(ElementEntity, IList, elementType, Index,
1719 StructuredList, StructuredIndex);
1720 }
1721
1722 if (VerifyOnly)
1723 return;
1724
1725 bool isBigEndian = SemaRef.Context.getTargetInfo().isBigEndian();
1726 const VectorType *T = Entity.getType()->castAs<VectorType>();
1727 if (isBigEndian && (T->getVectorKind() == VectorType::NeonVector ||
1728 T->getVectorKind() == VectorType::NeonPolyVector)) {
1729 // The ability to use vector initializer lists is a GNU vector extension
1730 // and is unrelated to the NEON intrinsics in arm_neon.h. On little
1731 // endian machines it works fine, however on big endian machines it
1732 // exhibits surprising behaviour:
1733 //
1734 // uint32x2_t x = {42, 64};
1735 // return vget_lane_u32(x, 0); // Will return 64.
1736 //
1737 // Because of this, explicitly call out that it is non-portable.
1738 //
1739 SemaRef.Diag(IList->getBeginLoc(),
1740 diag::warn_neon_vector_initializer_non_portable);
1741
1742 const char *typeCode;
1743 unsigned typeSize = SemaRef.Context.getTypeSize(elementType);
1744
1745 if (elementType->isFloatingType())
1746 typeCode = "f";
1747 else if (elementType->isSignedIntegerType())
1748 typeCode = "s";
1749 else if (elementType->isUnsignedIntegerType())
1750 typeCode = "u";
1751 else
1752 llvm_unreachable("Invalid element type!");
1753
1754 SemaRef.Diag(IList->getBeginLoc(),
1755 SemaRef.Context.getTypeSize(VT) > 64
1756 ? diag::note_neon_vector_initializer_non_portable_q
1757 : diag::note_neon_vector_initializer_non_portable)
1758 << typeCode << typeSize;
1759 }
1760
1761 return;
1762 }
1763
1764 InitializedEntity ElementEntity =
1765 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
1766
1767 // OpenCL initializers allows vectors to be constructed from vectors.
1768 for (unsigned i = 0; i < maxElements; ++i) {
1769 // Don't attempt to go past the end of the init list
1770 if (Index >= IList->getNumInits())
1771 break;
1772
1773 ElementEntity.setElementIndex(Index);
1774
1775 QualType IType = IList->getInit(Index)->getType();
1776 if (!IType->isVectorType()) {
1777 CheckSubElementType(ElementEntity, IList, elementType, Index,
1778 StructuredList, StructuredIndex);
1779 ++numEltsInit;
1780 } else {
1781 QualType VecType;
1782 const VectorType *IVT = IType->castAs<VectorType>();
1783 unsigned numIElts = IVT->getNumElements();
1784
1785 if (IType->isExtVectorType())
1786 VecType = SemaRef.Context.getExtVectorType(elementType, numIElts);
1787 else
1788 VecType = SemaRef.Context.getVectorType(elementType, numIElts,
1789 IVT->getVectorKind());
1790 CheckSubElementType(ElementEntity, IList, VecType, Index,
1791 StructuredList, StructuredIndex);
1792 numEltsInit += numIElts;
1793 }
1794 }
1795
1796 // OpenCL requires all elements to be initialized.
1797 if (numEltsInit != maxElements) {
1798 if (!VerifyOnly)
1799 SemaRef.Diag(IList->getBeginLoc(),
1800 diag::err_vector_incorrect_num_initializers)
1801 << (numEltsInit < maxElements) << maxElements << numEltsInit;
1802 hadError = true;
1803 }
1804 }
1805
1806 /// Check if the type of a class element has an accessible destructor, and marks
1807 /// it referenced. Returns true if we shouldn't form a reference to the
1808 /// destructor.
1809 ///
1810 /// Aggregate initialization requires a class element's destructor be
1811 /// accessible per 11.6.1 [dcl.init.aggr]:
1812 ///
1813 /// The destructor for each element of class type is potentially invoked
1814 /// (15.4 [class.dtor]) from the context where the aggregate initialization
1815 /// occurs.
checkDestructorReference(QualType ElementType,SourceLocation Loc,Sema & SemaRef)1816 static bool checkDestructorReference(QualType ElementType, SourceLocation Loc,
1817 Sema &SemaRef) {
1818 auto *CXXRD = ElementType->getAsCXXRecordDecl();
1819 if (!CXXRD)
1820 return false;
1821
1822 CXXDestructorDecl *Destructor = SemaRef.LookupDestructor(CXXRD);
1823 SemaRef.CheckDestructorAccess(Loc, Destructor,
1824 SemaRef.PDiag(diag::err_access_dtor_temp)
1825 << ElementType);
1826 SemaRef.MarkFunctionReferenced(Loc, Destructor);
1827 return SemaRef.DiagnoseUseOfDecl(Destructor, Loc);
1828 }
1829
CheckArrayType(const InitializedEntity & Entity,InitListExpr * IList,QualType & DeclType,llvm::APSInt elementIndex,bool SubobjectIsDesignatorContext,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1830 void InitListChecker::CheckArrayType(const InitializedEntity &Entity,
1831 InitListExpr *IList, QualType &DeclType,
1832 llvm::APSInt elementIndex,
1833 bool SubobjectIsDesignatorContext,
1834 unsigned &Index,
1835 InitListExpr *StructuredList,
1836 unsigned &StructuredIndex) {
1837 const ArrayType *arrayType = SemaRef.Context.getAsArrayType(DeclType);
1838
1839 if (!VerifyOnly) {
1840 if (checkDestructorReference(arrayType->getElementType(),
1841 IList->getEndLoc(), SemaRef)) {
1842 hadError = true;
1843 return;
1844 }
1845 }
1846
1847 // Check for the special-case of initializing an array with a string.
1848 if (Index < IList->getNumInits()) {
1849 if (IsStringInit(IList->getInit(Index), arrayType, SemaRef.Context) ==
1850 SIF_None) {
1851 // We place the string literal directly into the resulting
1852 // initializer list. This is the only place where the structure
1853 // of the structured initializer list doesn't match exactly,
1854 // because doing so would involve allocating one character
1855 // constant for each string.
1856 // FIXME: Should we do these checks in verify-only mode too?
1857 if (!VerifyOnly)
1858 CheckStringInit(IList->getInit(Index), DeclType, arrayType, SemaRef);
1859 if (StructuredList) {
1860 UpdateStructuredListElement(StructuredList, StructuredIndex,
1861 IList->getInit(Index));
1862 StructuredList->resizeInits(SemaRef.Context, StructuredIndex);
1863 }
1864 ++Index;
1865 return;
1866 }
1867 }
1868 if (const VariableArrayType *VAT = dyn_cast<VariableArrayType>(arrayType)) {
1869 // Check for VLAs; in standard C it would be possible to check this
1870 // earlier, but I don't know where clang accepts VLAs (gcc accepts
1871 // them in all sorts of strange places).
1872 if (!VerifyOnly)
1873 SemaRef.Diag(VAT->getSizeExpr()->getBeginLoc(),
1874 diag::err_variable_object_no_init)
1875 << VAT->getSizeExpr()->getSourceRange();
1876 hadError = true;
1877 ++Index;
1878 ++StructuredIndex;
1879 return;
1880 }
1881
1882 // We might know the maximum number of elements in advance.
1883 llvm::APSInt maxElements(elementIndex.getBitWidth(),
1884 elementIndex.isUnsigned());
1885 bool maxElementsKnown = false;
1886 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(arrayType)) {
1887 maxElements = CAT->getSize();
1888 elementIndex = elementIndex.extOrTrunc(maxElements.getBitWidth());
1889 elementIndex.setIsUnsigned(maxElements.isUnsigned());
1890 maxElementsKnown = true;
1891 }
1892
1893 QualType elementType = arrayType->getElementType();
1894 while (Index < IList->getNumInits()) {
1895 Expr *Init = IList->getInit(Index);
1896 if (DesignatedInitExpr *DIE = dyn_cast<DesignatedInitExpr>(Init)) {
1897 // If we're not the subobject that matches up with the '{' for
1898 // the designator, we shouldn't be handling the
1899 // designator. Return immediately.
1900 if (!SubobjectIsDesignatorContext)
1901 return;
1902
1903 // Handle this designated initializer. elementIndex will be
1904 // updated to be the next array element we'll initialize.
1905 if (CheckDesignatedInitializer(Entity, IList, DIE, 0,
1906 DeclType, nullptr, &elementIndex, Index,
1907 StructuredList, StructuredIndex, true,
1908 false)) {
1909 hadError = true;
1910 continue;
1911 }
1912
1913 if (elementIndex.getBitWidth() > maxElements.getBitWidth())
1914 maxElements = maxElements.extend(elementIndex.getBitWidth());
1915 else if (elementIndex.getBitWidth() < maxElements.getBitWidth())
1916 elementIndex = elementIndex.extend(maxElements.getBitWidth());
1917 elementIndex.setIsUnsigned(maxElements.isUnsigned());
1918
1919 // If the array is of incomplete type, keep track of the number of
1920 // elements in the initializer.
1921 if (!maxElementsKnown && elementIndex > maxElements)
1922 maxElements = elementIndex;
1923
1924 continue;
1925 }
1926
1927 // If we know the maximum number of elements, and we've already
1928 // hit it, stop consuming elements in the initializer list.
1929 if (maxElementsKnown && elementIndex == maxElements)
1930 break;
1931
1932 InitializedEntity ElementEntity =
1933 InitializedEntity::InitializeElement(SemaRef.Context, StructuredIndex,
1934 Entity);
1935 // Check this element.
1936 CheckSubElementType(ElementEntity, IList, elementType, Index,
1937 StructuredList, StructuredIndex);
1938 ++elementIndex;
1939
1940 // If the array is of incomplete type, keep track of the number of
1941 // elements in the initializer.
1942 if (!maxElementsKnown && elementIndex > maxElements)
1943 maxElements = elementIndex;
1944 }
1945 if (!hadError && DeclType->isIncompleteArrayType() && !VerifyOnly) {
1946 // If this is an incomplete array type, the actual type needs to
1947 // be calculated here.
1948 llvm::APSInt Zero(maxElements.getBitWidth(), maxElements.isUnsigned());
1949 if (maxElements == Zero && !Entity.isVariableLengthArrayNew()) {
1950 // Sizing an array implicitly to zero is not allowed by ISO C,
1951 // but is supported by GNU.
1952 SemaRef.Diag(IList->getBeginLoc(), diag::ext_typecheck_zero_array_size);
1953 }
1954
1955 DeclType = SemaRef.Context.getConstantArrayType(
1956 elementType, maxElements, nullptr, ArrayType::Normal, 0);
1957 }
1958 if (!hadError) {
1959 // If there are any members of the array that get value-initialized, check
1960 // that is possible. That happens if we know the bound and don't have
1961 // enough elements, or if we're performing an array new with an unknown
1962 // bound.
1963 if ((maxElementsKnown && elementIndex < maxElements) ||
1964 Entity.isVariableLengthArrayNew())
1965 CheckEmptyInitializable(
1966 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity),
1967 IList->getEndLoc());
1968 }
1969 }
1970
CheckFlexibleArrayInit(const InitializedEntity & Entity,Expr * InitExpr,FieldDecl * Field,bool TopLevelObject)1971 bool InitListChecker::CheckFlexibleArrayInit(const InitializedEntity &Entity,
1972 Expr *InitExpr,
1973 FieldDecl *Field,
1974 bool TopLevelObject) {
1975 // Handle GNU flexible array initializers.
1976 unsigned FlexArrayDiag;
1977 if (isa<InitListExpr>(InitExpr) &&
1978 cast<InitListExpr>(InitExpr)->getNumInits() == 0) {
1979 // Empty flexible array init always allowed as an extension
1980 FlexArrayDiag = diag::ext_flexible_array_init;
1981 } else if (SemaRef.getLangOpts().CPlusPlus) {
1982 // Disallow flexible array init in C++; it is not required for gcc
1983 // compatibility, and it needs work to IRGen correctly in general.
1984 FlexArrayDiag = diag::err_flexible_array_init;
1985 } else if (!TopLevelObject) {
1986 // Disallow flexible array init on non-top-level object
1987 FlexArrayDiag = diag::err_flexible_array_init;
1988 } else if (Entity.getKind() != InitializedEntity::EK_Variable) {
1989 // Disallow flexible array init on anything which is not a variable.
1990 FlexArrayDiag = diag::err_flexible_array_init;
1991 } else if (cast<VarDecl>(Entity.getDecl())->hasLocalStorage()) {
1992 // Disallow flexible array init on local variables.
1993 FlexArrayDiag = diag::err_flexible_array_init;
1994 } else {
1995 // Allow other cases.
1996 FlexArrayDiag = diag::ext_flexible_array_init;
1997 }
1998
1999 if (!VerifyOnly) {
2000 SemaRef.Diag(InitExpr->getBeginLoc(), FlexArrayDiag)
2001 << InitExpr->getBeginLoc();
2002 SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
2003 << Field;
2004 }
2005
2006 return FlexArrayDiag != diag::ext_flexible_array_init;
2007 }
2008
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)2009 void InitListChecker::CheckStructUnionTypes(
2010 const InitializedEntity &Entity, InitListExpr *IList, QualType DeclType,
2011 CXXRecordDecl::base_class_range Bases, RecordDecl::field_iterator Field,
2012 bool SubobjectIsDesignatorContext, unsigned &Index,
2013 InitListExpr *StructuredList, unsigned &StructuredIndex,
2014 bool TopLevelObject) {
2015 RecordDecl *structDecl = DeclType->castAs<RecordType>()->getDecl();
2016
2017 // If the record is invalid, some of it's members are invalid. To avoid
2018 // confusion, we forgo checking the intializer for the entire record.
2019 if (structDecl->isInvalidDecl()) {
2020 // Assume it was supposed to consume a single initializer.
2021 ++Index;
2022 hadError = true;
2023 return;
2024 }
2025
2026 if (DeclType->isUnionType() && IList->getNumInits() == 0) {
2027 RecordDecl *RD = DeclType->castAs<RecordType>()->getDecl();
2028
2029 if (!VerifyOnly)
2030 for (FieldDecl *FD : RD->fields()) {
2031 QualType ET = SemaRef.Context.getBaseElementType(FD->getType());
2032 if (checkDestructorReference(ET, IList->getEndLoc(), SemaRef)) {
2033 hadError = true;
2034 return;
2035 }
2036 }
2037
2038 // If there's a default initializer, use it.
2039 if (isa<CXXRecordDecl>(RD) &&
2040 cast<CXXRecordDecl>(RD)->hasInClassInitializer()) {
2041 if (!StructuredList)
2042 return;
2043 for (RecordDecl::field_iterator FieldEnd = RD->field_end();
2044 Field != FieldEnd; ++Field) {
2045 if (Field->hasInClassInitializer()) {
2046 StructuredList->setInitializedFieldInUnion(*Field);
2047 // FIXME: Actually build a CXXDefaultInitExpr?
2048 return;
2049 }
2050 }
2051 }
2052
2053 // Value-initialize the first member of the union that isn't an unnamed
2054 // bitfield.
2055 for (RecordDecl::field_iterator FieldEnd = RD->field_end();
2056 Field != FieldEnd; ++Field) {
2057 if (!Field->isUnnamedBitfield()) {
2058 CheckEmptyInitializable(
2059 InitializedEntity::InitializeMember(*Field, &Entity),
2060 IList->getEndLoc());
2061 if (StructuredList)
2062 StructuredList->setInitializedFieldInUnion(*Field);
2063 break;
2064 }
2065 }
2066 return;
2067 }
2068
2069 bool InitializedSomething = false;
2070
2071 // If we have any base classes, they are initialized prior to the fields.
2072 for (auto &Base : Bases) {
2073 Expr *Init = Index < IList->getNumInits() ? IList->getInit(Index) : nullptr;
2074
2075 // Designated inits always initialize fields, so if we see one, all
2076 // remaining base classes have no explicit initializer.
2077 if (Init && isa<DesignatedInitExpr>(Init))
2078 Init = nullptr;
2079
2080 SourceLocation InitLoc = Init ? Init->getBeginLoc() : IList->getEndLoc();
2081 InitializedEntity BaseEntity = InitializedEntity::InitializeBase(
2082 SemaRef.Context, &Base, false, &Entity);
2083 if (Init) {
2084 CheckSubElementType(BaseEntity, IList, Base.getType(), Index,
2085 StructuredList, StructuredIndex);
2086 InitializedSomething = true;
2087 } else {
2088 CheckEmptyInitializable(BaseEntity, InitLoc);
2089 }
2090
2091 if (!VerifyOnly)
2092 if (checkDestructorReference(Base.getType(), InitLoc, SemaRef)) {
2093 hadError = true;
2094 return;
2095 }
2096 }
2097
2098 // If structDecl is a forward declaration, this loop won't do
2099 // anything except look at designated initializers; That's okay,
2100 // because an error should get printed out elsewhere. It might be
2101 // worthwhile to skip over the rest of the initializer, though.
2102 RecordDecl *RD = DeclType->castAs<RecordType>()->getDecl();
2103 RecordDecl::field_iterator FieldEnd = RD->field_end();
2104 bool CheckForMissingFields =
2105 !IList->isIdiomaticZeroInitializer(SemaRef.getLangOpts());
2106 bool HasDesignatedInit = false;
2107
2108 while (Index < IList->getNumInits()) {
2109 Expr *Init = IList->getInit(Index);
2110 SourceLocation InitLoc = Init->getBeginLoc();
2111
2112 if (DesignatedInitExpr *DIE = dyn_cast<DesignatedInitExpr>(Init)) {
2113 // If we're not the subobject that matches up with the '{' for
2114 // the designator, we shouldn't be handling the
2115 // designator. Return immediately.
2116 if (!SubobjectIsDesignatorContext)
2117 return;
2118
2119 HasDesignatedInit = true;
2120
2121 // Handle this designated initializer. Field will be updated to
2122 // the next field that we'll be initializing.
2123 if (CheckDesignatedInitializer(Entity, IList, DIE, 0,
2124 DeclType, &Field, nullptr, Index,
2125 StructuredList, StructuredIndex,
2126 true, TopLevelObject))
2127 hadError = true;
2128 else if (!VerifyOnly) {
2129 // Find the field named by the designated initializer.
2130 RecordDecl::field_iterator F = RD->field_begin();
2131 while (std::next(F) != Field)
2132 ++F;
2133 QualType ET = SemaRef.Context.getBaseElementType(F->getType());
2134 if (checkDestructorReference(ET, InitLoc, SemaRef)) {
2135 hadError = true;
2136 return;
2137 }
2138 }
2139
2140 InitializedSomething = true;
2141
2142 // Disable check for missing fields when designators are used.
2143 // This matches gcc behaviour.
2144 CheckForMissingFields = false;
2145 continue;
2146 }
2147
2148 if (Field == FieldEnd) {
2149 // We've run out of fields. We're done.
2150 break;
2151 }
2152
2153 // We've already initialized a member of a union. We're done.
2154 if (InitializedSomething && DeclType->isUnionType())
2155 break;
2156
2157 // If we've hit the flexible array member at the end, we're done.
2158 if (Field->getType()->isIncompleteArrayType())
2159 break;
2160
2161 if (Field->isUnnamedBitfield()) {
2162 // Don't initialize unnamed bitfields, e.g. "int : 20;"
2163 ++Field;
2164 continue;
2165 }
2166
2167 // Make sure we can use this declaration.
2168 bool InvalidUse;
2169 if (VerifyOnly)
2170 InvalidUse = !SemaRef.CanUseDecl(*Field, TreatUnavailableAsInvalid);
2171 else
2172 InvalidUse = SemaRef.DiagnoseUseOfDecl(
2173 *Field, IList->getInit(Index)->getBeginLoc());
2174 if (InvalidUse) {
2175 ++Index;
2176 ++Field;
2177 hadError = true;
2178 continue;
2179 }
2180
2181 if (!VerifyOnly) {
2182 QualType ET = SemaRef.Context.getBaseElementType(Field->getType());
2183 if (checkDestructorReference(ET, InitLoc, SemaRef)) {
2184 hadError = true;
2185 return;
2186 }
2187 }
2188
2189 InitializedEntity MemberEntity =
2190 InitializedEntity::InitializeMember(*Field, &Entity);
2191 CheckSubElementType(MemberEntity, IList, Field->getType(), Index,
2192 StructuredList, StructuredIndex);
2193 InitializedSomething = true;
2194
2195 if (DeclType->isUnionType() && StructuredList) {
2196 // Initialize the first field within the union.
2197 StructuredList->setInitializedFieldInUnion(*Field);
2198 }
2199
2200 ++Field;
2201 }
2202
2203 // Emit warnings for missing struct field initializers.
2204 if (!VerifyOnly && InitializedSomething && CheckForMissingFields &&
2205 Field != FieldEnd && !Field->getType()->isIncompleteArrayType() &&
2206 !DeclType->isUnionType()) {
2207 // It is possible we have one or more unnamed bitfields remaining.
2208 // Find first (if any) named field and emit warning.
2209 for (RecordDecl::field_iterator it = Field, end = RD->field_end();
2210 it != end; ++it) {
2211 if (!it->isUnnamedBitfield() && !it->hasInClassInitializer()) {
2212 SemaRef.Diag(IList->getSourceRange().getEnd(),
2213 diag::warn_missing_field_initializers) << *it;
2214 break;
2215 }
2216 }
2217 }
2218
2219 // Check that any remaining fields can be value-initialized if we're not
2220 // building a structured list. (If we are, we'll check this later.)
2221 if (!StructuredList && Field != FieldEnd && !DeclType->isUnionType() &&
2222 !Field->getType()->isIncompleteArrayType()) {
2223 for (; Field != FieldEnd && !hadError; ++Field) {
2224 if (!Field->isUnnamedBitfield() && !Field->hasInClassInitializer())
2225 CheckEmptyInitializable(
2226 InitializedEntity::InitializeMember(*Field, &Entity),
2227 IList->getEndLoc());
2228 }
2229 }
2230
2231 // Check that the types of the remaining fields have accessible destructors.
2232 if (!VerifyOnly) {
2233 // If the initializer expression has a designated initializer, check the
2234 // elements for which a designated initializer is not provided too.
2235 RecordDecl::field_iterator I = HasDesignatedInit ? RD->field_begin()
2236 : Field;
2237 for (RecordDecl::field_iterator E = RD->field_end(); I != E; ++I) {
2238 QualType ET = SemaRef.Context.getBaseElementType(I->getType());
2239 if (checkDestructorReference(ET, IList->getEndLoc(), SemaRef)) {
2240 hadError = true;
2241 return;
2242 }
2243 }
2244 }
2245
2246 if (Field == FieldEnd || !Field->getType()->isIncompleteArrayType() ||
2247 Index >= IList->getNumInits())
2248 return;
2249
2250 if (CheckFlexibleArrayInit(Entity, IList->getInit(Index), *Field,
2251 TopLevelObject)) {
2252 hadError = true;
2253 ++Index;
2254 return;
2255 }
2256
2257 InitializedEntity MemberEntity =
2258 InitializedEntity::InitializeMember(*Field, &Entity);
2259
2260 if (isa<InitListExpr>(IList->getInit(Index)))
2261 CheckSubElementType(MemberEntity, IList, Field->getType(), Index,
2262 StructuredList, StructuredIndex);
2263 else
2264 CheckImplicitInitList(MemberEntity, IList, Field->getType(), Index,
2265 StructuredList, StructuredIndex);
2266 }
2267
2268 /// Expand a field designator that refers to a member of an
2269 /// anonymous struct or union into a series of field designators that
2270 /// refers to the field within the appropriate subobject.
2271 ///
ExpandAnonymousFieldDesignator(Sema & SemaRef,DesignatedInitExpr * DIE,unsigned DesigIdx,IndirectFieldDecl * IndirectField)2272 static void ExpandAnonymousFieldDesignator(Sema &SemaRef,
2273 DesignatedInitExpr *DIE,
2274 unsigned DesigIdx,
2275 IndirectFieldDecl *IndirectField) {
2276 typedef DesignatedInitExpr::Designator Designator;
2277
2278 // Build the replacement designators.
2279 SmallVector<Designator, 4> Replacements;
2280 for (IndirectFieldDecl::chain_iterator PI = IndirectField->chain_begin(),
2281 PE = IndirectField->chain_end(); PI != PE; ++PI) {
2282 if (PI + 1 == PE)
2283 Replacements.push_back(Designator((IdentifierInfo *)nullptr,
2284 DIE->getDesignator(DesigIdx)->getDotLoc(),
2285 DIE->getDesignator(DesigIdx)->getFieldLoc()));
2286 else
2287 Replacements.push_back(Designator((IdentifierInfo *)nullptr,
2288 SourceLocation(), SourceLocation()));
2289 assert(isa<FieldDecl>(*PI));
2290 Replacements.back().setField(cast<FieldDecl>(*PI));
2291 }
2292
2293 // Expand the current designator into the set of replacement
2294 // designators, so we have a full subobject path down to where the
2295 // member of the anonymous struct/union is actually stored.
2296 DIE->ExpandDesignator(SemaRef.Context, DesigIdx, &Replacements[0],
2297 &Replacements[0] + Replacements.size());
2298 }
2299
CloneDesignatedInitExpr(Sema & SemaRef,DesignatedInitExpr * DIE)2300 static DesignatedInitExpr *CloneDesignatedInitExpr(Sema &SemaRef,
2301 DesignatedInitExpr *DIE) {
2302 unsigned NumIndexExprs = DIE->getNumSubExprs() - 1;
2303 SmallVector<Expr*, 4> IndexExprs(NumIndexExprs);
2304 for (unsigned I = 0; I < NumIndexExprs; ++I)
2305 IndexExprs[I] = DIE->getSubExpr(I + 1);
2306 return DesignatedInitExpr::Create(SemaRef.Context, DIE->designators(),
2307 IndexExprs,
2308 DIE->getEqualOrColonLoc(),
2309 DIE->usesGNUSyntax(), DIE->getInit());
2310 }
2311
2312 namespace {
2313
2314 // Callback to only accept typo corrections that are for field members of
2315 // the given struct or union.
2316 class FieldInitializerValidatorCCC final : public CorrectionCandidateCallback {
2317 public:
FieldInitializerValidatorCCC(RecordDecl * RD)2318 explicit FieldInitializerValidatorCCC(RecordDecl *RD)
2319 : Record(RD) {}
2320
ValidateCandidate(const TypoCorrection & candidate)2321 bool ValidateCandidate(const TypoCorrection &candidate) override {
2322 FieldDecl *FD = candidate.getCorrectionDeclAs<FieldDecl>();
2323 return FD && FD->getDeclContext()->getRedeclContext()->Equals(Record);
2324 }
2325
clone()2326 std::unique_ptr<CorrectionCandidateCallback> clone() override {
2327 return std::make_unique<FieldInitializerValidatorCCC>(*this);
2328 }
2329
2330 private:
2331 RecordDecl *Record;
2332 };
2333
2334 } // end anonymous namespace
2335
2336 /// Check the well-formedness of a C99 designated initializer.
2337 ///
2338 /// Determines whether the designated initializer @p DIE, which
2339 /// resides at the given @p Index within the initializer list @p
2340 /// IList, is well-formed for a current object of type @p DeclType
2341 /// (C99 6.7.8). The actual subobject that this designator refers to
2342 /// within the current subobject is returned in either
2343 /// @p NextField or @p NextElementIndex (whichever is appropriate).
2344 ///
2345 /// @param IList The initializer list in which this designated
2346 /// initializer occurs.
2347 ///
2348 /// @param DIE The designated initializer expression.
2349 ///
2350 /// @param DesigIdx The index of the current designator.
2351 ///
2352 /// @param CurrentObjectType The type of the "current object" (C99 6.7.8p17),
2353 /// into which the designation in @p DIE should refer.
2354 ///
2355 /// @param NextField If non-NULL and the first designator in @p DIE is
2356 /// a field, this will be set to the field declaration corresponding
2357 /// to the field named by the designator. On input, this is expected to be
2358 /// the next field that would be initialized in the absence of designation,
2359 /// if the complete object being initialized is a struct.
2360 ///
2361 /// @param NextElementIndex If non-NULL and the first designator in @p
2362 /// DIE is an array designator or GNU array-range designator, this
2363 /// will be set to the last index initialized by this designator.
2364 ///
2365 /// @param Index Index into @p IList where the designated initializer
2366 /// @p DIE occurs.
2367 ///
2368 /// @param StructuredList The initializer list expression that
2369 /// describes all of the subobject initializers in the order they'll
2370 /// actually be initialized.
2371 ///
2372 /// @returns true if there was an error, false otherwise.
2373 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)2374 InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity,
2375 InitListExpr *IList,
2376 DesignatedInitExpr *DIE,
2377 unsigned DesigIdx,
2378 QualType &CurrentObjectType,
2379 RecordDecl::field_iterator *NextField,
2380 llvm::APSInt *NextElementIndex,
2381 unsigned &Index,
2382 InitListExpr *StructuredList,
2383 unsigned &StructuredIndex,
2384 bool FinishSubobjectInit,
2385 bool TopLevelObject) {
2386 if (DesigIdx == DIE->size()) {
2387 // C++20 designated initialization can result in direct-list-initialization
2388 // of the designated subobject. This is the only way that we can end up
2389 // performing direct initialization as part of aggregate initialization, so
2390 // it needs special handling.
2391 if (DIE->isDirectInit()) {
2392 Expr *Init = DIE->getInit();
2393 assert(isa<InitListExpr>(Init) &&
2394 "designator result in direct non-list initialization?");
2395 InitializationKind Kind = InitializationKind::CreateDirectList(
2396 DIE->getBeginLoc(), Init->getBeginLoc(), Init->getEndLoc());
2397 InitializationSequence Seq(SemaRef, Entity, Kind, Init,
2398 /*TopLevelOfInitList*/ true);
2399 if (StructuredList) {
2400 ExprResult Result = VerifyOnly
2401 ? getDummyInit()
2402 : Seq.Perform(SemaRef, Entity, Kind, Init);
2403 UpdateStructuredListElement(StructuredList, StructuredIndex,
2404 Result.get());
2405 }
2406 ++Index;
2407 return !Seq;
2408 }
2409
2410 // Check the actual initialization for the designated object type.
2411 bool prevHadError = hadError;
2412
2413 // Temporarily remove the designator expression from the
2414 // initializer list that the child calls see, so that we don't try
2415 // to re-process the designator.
2416 unsigned OldIndex = Index;
2417 IList->setInit(OldIndex, DIE->getInit());
2418
2419 CheckSubElementType(Entity, IList, CurrentObjectType, Index,
2420 StructuredList, StructuredIndex);
2421
2422 // Restore the designated initializer expression in the syntactic
2423 // form of the initializer list.
2424 if (IList->getInit(OldIndex) != DIE->getInit())
2425 DIE->setInit(IList->getInit(OldIndex));
2426 IList->setInit(OldIndex, DIE);
2427
2428 return hadError && !prevHadError;
2429 }
2430
2431 DesignatedInitExpr::Designator *D = DIE->getDesignator(DesigIdx);
2432 bool IsFirstDesignator = (DesigIdx == 0);
2433 if (IsFirstDesignator ? FullyStructuredList : StructuredList) {
2434 // Determine the structural initializer list that corresponds to the
2435 // current subobject.
2436 if (IsFirstDesignator)
2437 StructuredList = FullyStructuredList;
2438 else {
2439 Expr *ExistingInit = StructuredIndex < StructuredList->getNumInits() ?
2440 StructuredList->getInit(StructuredIndex) : nullptr;
2441 if (!ExistingInit && StructuredList->hasArrayFiller())
2442 ExistingInit = StructuredList->getArrayFiller();
2443
2444 if (!ExistingInit)
2445 StructuredList = getStructuredSubobjectInit(
2446 IList, Index, CurrentObjectType, StructuredList, StructuredIndex,
2447 SourceRange(D->getBeginLoc(), DIE->getEndLoc()));
2448 else if (InitListExpr *Result = dyn_cast<InitListExpr>(ExistingInit))
2449 StructuredList = Result;
2450 else {
2451 // We are creating an initializer list that initializes the
2452 // subobjects of the current object, but there was already an
2453 // initialization that completely initialized the current
2454 // subobject, e.g., by a compound literal:
2455 //
2456 // struct X { int a, b; };
2457 // struct X xs[] = { [0] = (struct X) { 1, 2 }, [0].b = 3 };
2458 //
2459 // Here, xs[0].a == 1 and xs[0].b == 3, since the second,
2460 // designated initializer re-initializes only its current object
2461 // subobject [0].b.
2462 diagnoseInitOverride(ExistingInit,
2463 SourceRange(D->getBeginLoc(), DIE->getEndLoc()),
2464 /*FullyOverwritten=*/false);
2465
2466 if (!VerifyOnly) {
2467 if (DesignatedInitUpdateExpr *E =
2468 dyn_cast<DesignatedInitUpdateExpr>(ExistingInit))
2469 StructuredList = E->getUpdater();
2470 else {
2471 DesignatedInitUpdateExpr *DIUE = new (SemaRef.Context)
2472 DesignatedInitUpdateExpr(SemaRef.Context, D->getBeginLoc(),
2473 ExistingInit, DIE->getEndLoc());
2474 StructuredList->updateInit(SemaRef.Context, StructuredIndex, DIUE);
2475 StructuredList = DIUE->getUpdater();
2476 }
2477 } else {
2478 // We don't need to track the structured representation of a
2479 // designated init update of an already-fully-initialized object in
2480 // verify-only mode. The only reason we would need the structure is
2481 // to determine where the uninitialized "holes" are, and in this
2482 // case, we know there aren't any and we can't introduce any.
2483 StructuredList = nullptr;
2484 }
2485 }
2486 }
2487 }
2488
2489 if (D->isFieldDesignator()) {
2490 // C99 6.7.8p7:
2491 //
2492 // If a designator has the form
2493 //
2494 // . identifier
2495 //
2496 // then the current object (defined below) shall have
2497 // structure or union type and the identifier shall be the
2498 // name of a member of that type.
2499 const RecordType *RT = CurrentObjectType->getAs<RecordType>();
2500 if (!RT) {
2501 SourceLocation Loc = D->getDotLoc();
2502 if (Loc.isInvalid())
2503 Loc = D->getFieldLoc();
2504 if (!VerifyOnly)
2505 SemaRef.Diag(Loc, diag::err_field_designator_non_aggr)
2506 << SemaRef.getLangOpts().CPlusPlus << CurrentObjectType;
2507 ++Index;
2508 return true;
2509 }
2510
2511 FieldDecl *KnownField = D->getField();
2512 if (!KnownField) {
2513 IdentifierInfo *FieldName = D->getFieldName();
2514 DeclContext::lookup_result Lookup = RT->getDecl()->lookup(FieldName);
2515 for (NamedDecl *ND : Lookup) {
2516 if (auto *FD = dyn_cast<FieldDecl>(ND)) {
2517 KnownField = FD;
2518 break;
2519 }
2520 if (auto *IFD = dyn_cast<IndirectFieldDecl>(ND)) {
2521 // In verify mode, don't modify the original.
2522 if (VerifyOnly)
2523 DIE = CloneDesignatedInitExpr(SemaRef, DIE);
2524 ExpandAnonymousFieldDesignator(SemaRef, DIE, DesigIdx, IFD);
2525 D = DIE->getDesignator(DesigIdx);
2526 KnownField = cast<FieldDecl>(*IFD->chain_begin());
2527 break;
2528 }
2529 }
2530 if (!KnownField) {
2531 if (VerifyOnly) {
2532 ++Index;
2533 return true; // No typo correction when just trying this out.
2534 }
2535
2536 // Name lookup found something, but it wasn't a field.
2537 if (!Lookup.empty()) {
2538 SemaRef.Diag(D->getFieldLoc(), diag::err_field_designator_nonfield)
2539 << FieldName;
2540 SemaRef.Diag(Lookup.front()->getLocation(),
2541 diag::note_field_designator_found);
2542 ++Index;
2543 return true;
2544 }
2545
2546 // Name lookup didn't find anything.
2547 // Determine whether this was a typo for another field name.
2548 FieldInitializerValidatorCCC CCC(RT->getDecl());
2549 if (TypoCorrection Corrected = SemaRef.CorrectTypo(
2550 DeclarationNameInfo(FieldName, D->getFieldLoc()),
2551 Sema::LookupMemberName, /*Scope=*/nullptr, /*SS=*/nullptr, CCC,
2552 Sema::CTK_ErrorRecovery, RT->getDecl())) {
2553 SemaRef.diagnoseTypo(
2554 Corrected,
2555 SemaRef.PDiag(diag::err_field_designator_unknown_suggest)
2556 << FieldName << CurrentObjectType);
2557 KnownField = Corrected.getCorrectionDeclAs<FieldDecl>();
2558 hadError = true;
2559 } else {
2560 // Typo correction didn't find anything.
2561 SemaRef.Diag(D->getFieldLoc(), diag::err_field_designator_unknown)
2562 << FieldName << CurrentObjectType;
2563 ++Index;
2564 return true;
2565 }
2566 }
2567 }
2568
2569 unsigned NumBases = 0;
2570 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RT->getDecl()))
2571 NumBases = CXXRD->getNumBases();
2572
2573 unsigned FieldIndex = NumBases;
2574
2575 for (auto *FI : RT->getDecl()->fields()) {
2576 if (FI->isUnnamedBitfield())
2577 continue;
2578 if (declaresSameEntity(KnownField, FI)) {
2579 KnownField = FI;
2580 break;
2581 }
2582 ++FieldIndex;
2583 }
2584
2585 RecordDecl::field_iterator Field =
2586 RecordDecl::field_iterator(DeclContext::decl_iterator(KnownField));
2587
2588 // All of the fields of a union are located at the same place in
2589 // the initializer list.
2590 if (RT->getDecl()->isUnion()) {
2591 FieldIndex = 0;
2592 if (StructuredList) {
2593 FieldDecl *CurrentField = StructuredList->getInitializedFieldInUnion();
2594 if (CurrentField && !declaresSameEntity(CurrentField, *Field)) {
2595 assert(StructuredList->getNumInits() == 1
2596 && "A union should never have more than one initializer!");
2597
2598 Expr *ExistingInit = StructuredList->getInit(0);
2599 if (ExistingInit) {
2600 // We're about to throw away an initializer, emit warning.
2601 diagnoseInitOverride(
2602 ExistingInit, SourceRange(D->getBeginLoc(), DIE->getEndLoc()));
2603 }
2604
2605 // remove existing initializer
2606 StructuredList->resizeInits(SemaRef.Context, 0);
2607 StructuredList->setInitializedFieldInUnion(nullptr);
2608 }
2609
2610 StructuredList->setInitializedFieldInUnion(*Field);
2611 }
2612 }
2613
2614 // Make sure we can use this declaration.
2615 bool InvalidUse;
2616 if (VerifyOnly)
2617 InvalidUse = !SemaRef.CanUseDecl(*Field, TreatUnavailableAsInvalid);
2618 else
2619 InvalidUse = SemaRef.DiagnoseUseOfDecl(*Field, D->getFieldLoc());
2620 if (InvalidUse) {
2621 ++Index;
2622 return true;
2623 }
2624
2625 // C++20 [dcl.init.list]p3:
2626 // The ordered identifiers in the designators of the designated-
2627 // initializer-list shall form a subsequence of the ordered identifiers
2628 // in the direct non-static data members of T.
2629 //
2630 // Note that this is not a condition on forming the aggregate
2631 // initialization, only on actually performing initialization,
2632 // so it is not checked in VerifyOnly mode.
2633 //
2634 // FIXME: This is the only reordering diagnostic we produce, and it only
2635 // catches cases where we have a top-level field designator that jumps
2636 // backwards. This is the only such case that is reachable in an
2637 // otherwise-valid C++20 program, so is the only case that's required for
2638 // conformance, but for consistency, we should diagnose all the other
2639 // cases where a designator takes us backwards too.
2640 if (IsFirstDesignator && !VerifyOnly && SemaRef.getLangOpts().CPlusPlus &&
2641 NextField &&
2642 (*NextField == RT->getDecl()->field_end() ||
2643 (*NextField)->getFieldIndex() > Field->getFieldIndex() + 1)) {
2644 // Find the field that we just initialized.
2645 FieldDecl *PrevField = nullptr;
2646 for (auto FI = RT->getDecl()->field_begin();
2647 FI != RT->getDecl()->field_end(); ++FI) {
2648 if (FI->isUnnamedBitfield())
2649 continue;
2650 if (*NextField != RT->getDecl()->field_end() &&
2651 declaresSameEntity(*FI, **NextField))
2652 break;
2653 PrevField = *FI;
2654 }
2655
2656 if (PrevField &&
2657 PrevField->getFieldIndex() > KnownField->getFieldIndex()) {
2658 SemaRef.Diag(DIE->getBeginLoc(), diag::ext_designated_init_reordered)
2659 << KnownField << PrevField << DIE->getSourceRange();
2660
2661 unsigned OldIndex = NumBases + PrevField->getFieldIndex();
2662 if (StructuredList && OldIndex <= StructuredList->getNumInits()) {
2663 if (Expr *PrevInit = StructuredList->getInit(OldIndex)) {
2664 SemaRef.Diag(PrevInit->getBeginLoc(),
2665 diag::note_previous_field_init)
2666 << PrevField << PrevInit->getSourceRange();
2667 }
2668 }
2669 }
2670 }
2671
2672
2673 // Update the designator with the field declaration.
2674 if (!VerifyOnly)
2675 D->setField(*Field);
2676
2677 // Make sure that our non-designated initializer list has space
2678 // for a subobject corresponding to this field.
2679 if (StructuredList && FieldIndex >= StructuredList->getNumInits())
2680 StructuredList->resizeInits(SemaRef.Context, FieldIndex + 1);
2681
2682 // This designator names a flexible array member.
2683 if (Field->getType()->isIncompleteArrayType()) {
2684 bool Invalid = false;
2685 if ((DesigIdx + 1) != DIE->size()) {
2686 // We can't designate an object within the flexible array
2687 // member (because GCC doesn't allow it).
2688 if (!VerifyOnly) {
2689 DesignatedInitExpr::Designator *NextD
2690 = DIE->getDesignator(DesigIdx + 1);
2691 SemaRef.Diag(NextD->getBeginLoc(),
2692 diag::err_designator_into_flexible_array_member)
2693 << SourceRange(NextD->getBeginLoc(), DIE->getEndLoc());
2694 SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
2695 << *Field;
2696 }
2697 Invalid = true;
2698 }
2699
2700 if (!hadError && !isa<InitListExpr>(DIE->getInit()) &&
2701 !isa<StringLiteral>(DIE->getInit())) {
2702 // The initializer is not an initializer list.
2703 if (!VerifyOnly) {
2704 SemaRef.Diag(DIE->getInit()->getBeginLoc(),
2705 diag::err_flexible_array_init_needs_braces)
2706 << DIE->getInit()->getSourceRange();
2707 SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
2708 << *Field;
2709 }
2710 Invalid = true;
2711 }
2712
2713 // Check GNU flexible array initializer.
2714 if (!Invalid && CheckFlexibleArrayInit(Entity, DIE->getInit(), *Field,
2715 TopLevelObject))
2716 Invalid = true;
2717
2718 if (Invalid) {
2719 ++Index;
2720 return true;
2721 }
2722
2723 // Initialize the array.
2724 bool prevHadError = hadError;
2725 unsigned newStructuredIndex = FieldIndex;
2726 unsigned OldIndex = Index;
2727 IList->setInit(Index, DIE->getInit());
2728
2729 InitializedEntity MemberEntity =
2730 InitializedEntity::InitializeMember(*Field, &Entity);
2731 CheckSubElementType(MemberEntity, IList, Field->getType(), Index,
2732 StructuredList, newStructuredIndex);
2733
2734 IList->setInit(OldIndex, DIE);
2735 if (hadError && !prevHadError) {
2736 ++Field;
2737 ++FieldIndex;
2738 if (NextField)
2739 *NextField = Field;
2740 StructuredIndex = FieldIndex;
2741 return true;
2742 }
2743 } else {
2744 // Recurse to check later designated subobjects.
2745 QualType FieldType = Field->getType();
2746 unsigned newStructuredIndex = FieldIndex;
2747
2748 InitializedEntity MemberEntity =
2749 InitializedEntity::InitializeMember(*Field, &Entity);
2750 if (CheckDesignatedInitializer(MemberEntity, IList, DIE, DesigIdx + 1,
2751 FieldType, nullptr, nullptr, Index,
2752 StructuredList, newStructuredIndex,
2753 FinishSubobjectInit, false))
2754 return true;
2755 }
2756
2757 // Find the position of the next field to be initialized in this
2758 // subobject.
2759 ++Field;
2760 ++FieldIndex;
2761
2762 // If this the first designator, our caller will continue checking
2763 // the rest of this struct/class/union subobject.
2764 if (IsFirstDesignator) {
2765 if (NextField)
2766 *NextField = Field;
2767 StructuredIndex = FieldIndex;
2768 return false;
2769 }
2770
2771 if (!FinishSubobjectInit)
2772 return false;
2773
2774 // We've already initialized something in the union; we're done.
2775 if (RT->getDecl()->isUnion())
2776 return hadError;
2777
2778 // Check the remaining fields within this class/struct/union subobject.
2779 bool prevHadError = hadError;
2780
2781 auto NoBases =
2782 CXXRecordDecl::base_class_range(CXXRecordDecl::base_class_iterator(),
2783 CXXRecordDecl::base_class_iterator());
2784 CheckStructUnionTypes(Entity, IList, CurrentObjectType, NoBases, Field,
2785 false, Index, StructuredList, FieldIndex);
2786 return hadError && !prevHadError;
2787 }
2788
2789 // C99 6.7.8p6:
2790 //
2791 // If a designator has the form
2792 //
2793 // [ constant-expression ]
2794 //
2795 // then the current object (defined below) shall have array
2796 // type and the expression shall be an integer constant
2797 // expression. If the array is of unknown size, any
2798 // nonnegative value is valid.
2799 //
2800 // Additionally, cope with the GNU extension that permits
2801 // designators of the form
2802 //
2803 // [ constant-expression ... constant-expression ]
2804 const ArrayType *AT = SemaRef.Context.getAsArrayType(CurrentObjectType);
2805 if (!AT) {
2806 if (!VerifyOnly)
2807 SemaRef.Diag(D->getLBracketLoc(), diag::err_array_designator_non_array)
2808 << CurrentObjectType;
2809 ++Index;
2810 return true;
2811 }
2812
2813 Expr *IndexExpr = nullptr;
2814 llvm::APSInt DesignatedStartIndex, DesignatedEndIndex;
2815 if (D->isArrayDesignator()) {
2816 IndexExpr = DIE->getArrayIndex(*D);
2817 DesignatedStartIndex = IndexExpr->EvaluateKnownConstInt(SemaRef.Context);
2818 DesignatedEndIndex = DesignatedStartIndex;
2819 } else {
2820 assert(D->isArrayRangeDesignator() && "Need array-range designator");
2821
2822 DesignatedStartIndex =
2823 DIE->getArrayRangeStart(*D)->EvaluateKnownConstInt(SemaRef.Context);
2824 DesignatedEndIndex =
2825 DIE->getArrayRangeEnd(*D)->EvaluateKnownConstInt(SemaRef.Context);
2826 IndexExpr = DIE->getArrayRangeEnd(*D);
2827
2828 // Codegen can't handle evaluating array range designators that have side
2829 // effects, because we replicate the AST value for each initialized element.
2830 // As such, set the sawArrayRangeDesignator() bit if we initialize multiple
2831 // elements with something that has a side effect, so codegen can emit an
2832 // "error unsupported" error instead of miscompiling the app.
2833 if (DesignatedStartIndex.getZExtValue()!=DesignatedEndIndex.getZExtValue()&&
2834 DIE->getInit()->HasSideEffects(SemaRef.Context) && !VerifyOnly)
2835 FullyStructuredList->sawArrayRangeDesignator();
2836 }
2837
2838 if (isa<ConstantArrayType>(AT)) {
2839 llvm::APSInt MaxElements(cast<ConstantArrayType>(AT)->getSize(), false);
2840 DesignatedStartIndex
2841 = DesignatedStartIndex.extOrTrunc(MaxElements.getBitWidth());
2842 DesignatedStartIndex.setIsUnsigned(MaxElements.isUnsigned());
2843 DesignatedEndIndex
2844 = DesignatedEndIndex.extOrTrunc(MaxElements.getBitWidth());
2845 DesignatedEndIndex.setIsUnsigned(MaxElements.isUnsigned());
2846 if (DesignatedEndIndex >= MaxElements) {
2847 if (!VerifyOnly)
2848 SemaRef.Diag(IndexExpr->getBeginLoc(),
2849 diag::err_array_designator_too_large)
2850 << DesignatedEndIndex.toString(10) << MaxElements.toString(10)
2851 << IndexExpr->getSourceRange();
2852 ++Index;
2853 return true;
2854 }
2855 } else {
2856 unsigned DesignatedIndexBitWidth =
2857 ConstantArrayType::getMaxSizeBits(SemaRef.Context);
2858 DesignatedStartIndex =
2859 DesignatedStartIndex.extOrTrunc(DesignatedIndexBitWidth);
2860 DesignatedEndIndex =
2861 DesignatedEndIndex.extOrTrunc(DesignatedIndexBitWidth);
2862 DesignatedStartIndex.setIsUnsigned(true);
2863 DesignatedEndIndex.setIsUnsigned(true);
2864 }
2865
2866 bool IsStringLiteralInitUpdate =
2867 StructuredList && StructuredList->isStringLiteralInit();
2868 if (IsStringLiteralInitUpdate && VerifyOnly) {
2869 // We're just verifying an update to a string literal init. We don't need
2870 // to split the string up into individual characters to do that.
2871 StructuredList = nullptr;
2872 } else if (IsStringLiteralInitUpdate) {
2873 // We're modifying a string literal init; we have to decompose the string
2874 // so we can modify the individual characters.
2875 ASTContext &Context = SemaRef.Context;
2876 Expr *SubExpr = StructuredList->getInit(0)->IgnoreParens();
2877
2878 // Compute the character type
2879 QualType CharTy = AT->getElementType();
2880
2881 // Compute the type of the integer literals.
2882 QualType PromotedCharTy = CharTy;
2883 if (CharTy->isPromotableIntegerType())
2884 PromotedCharTy = Context.getPromotedIntegerType(CharTy);
2885 unsigned PromotedCharTyWidth = Context.getTypeSize(PromotedCharTy);
2886
2887 if (StringLiteral *SL = dyn_cast<StringLiteral>(SubExpr)) {
2888 // Get the length of the string.
2889 uint64_t StrLen = SL->getLength();
2890 if (cast<ConstantArrayType>(AT)->getSize().ult(StrLen))
2891 StrLen = cast<ConstantArrayType>(AT)->getSize().getZExtValue();
2892 StructuredList->resizeInits(Context, StrLen);
2893
2894 // Build a literal for each character in the string, and put them into
2895 // the init list.
2896 for (unsigned i = 0, e = StrLen; i != e; ++i) {
2897 llvm::APInt CodeUnit(PromotedCharTyWidth, SL->getCodeUnit(i));
2898 Expr *Init = new (Context) IntegerLiteral(
2899 Context, CodeUnit, PromotedCharTy, SubExpr->getExprLoc());
2900 if (CharTy != PromotedCharTy)
2901 Init = ImplicitCastExpr::Create(Context, CharTy, CK_IntegralCast,
2902 Init, nullptr, VK_RValue);
2903 StructuredList->updateInit(Context, i, Init);
2904 }
2905 } else {
2906 ObjCEncodeExpr *E = cast<ObjCEncodeExpr>(SubExpr);
2907 std::string Str;
2908 Context.getObjCEncodingForType(E->getEncodedType(), Str);
2909
2910 // Get the length of the string.
2911 uint64_t StrLen = Str.size();
2912 if (cast<ConstantArrayType>(AT)->getSize().ult(StrLen))
2913 StrLen = cast<ConstantArrayType>(AT)->getSize().getZExtValue();
2914 StructuredList->resizeInits(Context, StrLen);
2915
2916 // Build a literal for each character in the string, and put them into
2917 // the init list.
2918 for (unsigned i = 0, e = StrLen; i != e; ++i) {
2919 llvm::APInt CodeUnit(PromotedCharTyWidth, Str[i]);
2920 Expr *Init = new (Context) IntegerLiteral(
2921 Context, CodeUnit, PromotedCharTy, SubExpr->getExprLoc());
2922 if (CharTy != PromotedCharTy)
2923 Init = ImplicitCastExpr::Create(Context, CharTy, CK_IntegralCast,
2924 Init, nullptr, VK_RValue);
2925 StructuredList->updateInit(Context, i, Init);
2926 }
2927 }
2928 }
2929
2930 // Make sure that our non-designated initializer list has space
2931 // for a subobject corresponding to this array element.
2932 if (StructuredList &&
2933 DesignatedEndIndex.getZExtValue() >= StructuredList->getNumInits())
2934 StructuredList->resizeInits(SemaRef.Context,
2935 DesignatedEndIndex.getZExtValue() + 1);
2936
2937 // Repeatedly perform subobject initializations in the range
2938 // [DesignatedStartIndex, DesignatedEndIndex].
2939
2940 // Move to the next designator
2941 unsigned ElementIndex = DesignatedStartIndex.getZExtValue();
2942 unsigned OldIndex = Index;
2943
2944 InitializedEntity ElementEntity =
2945 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
2946
2947 while (DesignatedStartIndex <= DesignatedEndIndex) {
2948 // Recurse to check later designated subobjects.
2949 QualType ElementType = AT->getElementType();
2950 Index = OldIndex;
2951
2952 ElementEntity.setElementIndex(ElementIndex);
2953 if (CheckDesignatedInitializer(
2954 ElementEntity, IList, DIE, DesigIdx + 1, ElementType, nullptr,
2955 nullptr, Index, StructuredList, ElementIndex,
2956 FinishSubobjectInit && (DesignatedStartIndex == DesignatedEndIndex),
2957 false))
2958 return true;
2959
2960 // Move to the next index in the array that we'll be initializing.
2961 ++DesignatedStartIndex;
2962 ElementIndex = DesignatedStartIndex.getZExtValue();
2963 }
2964
2965 // If this the first designator, our caller will continue checking
2966 // the rest of this array subobject.
2967 if (IsFirstDesignator) {
2968 if (NextElementIndex)
2969 *NextElementIndex = DesignatedStartIndex;
2970 StructuredIndex = ElementIndex;
2971 return false;
2972 }
2973
2974 if (!FinishSubobjectInit)
2975 return false;
2976
2977 // Check the remaining elements within this array subobject.
2978 bool prevHadError = hadError;
2979 CheckArrayType(Entity, IList, CurrentObjectType, DesignatedStartIndex,
2980 /*SubobjectIsDesignatorContext=*/false, Index,
2981 StructuredList, ElementIndex);
2982 return hadError && !prevHadError;
2983 }
2984
2985 // Get the structured initializer list for a subobject of type
2986 // @p CurrentObjectType.
2987 InitListExpr *
getStructuredSubobjectInit(InitListExpr * IList,unsigned Index,QualType CurrentObjectType,InitListExpr * StructuredList,unsigned StructuredIndex,SourceRange InitRange,bool IsFullyOverwritten)2988 InitListChecker::getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
2989 QualType CurrentObjectType,
2990 InitListExpr *StructuredList,
2991 unsigned StructuredIndex,
2992 SourceRange InitRange,
2993 bool IsFullyOverwritten) {
2994 if (!StructuredList)
2995 return nullptr;
2996
2997 Expr *ExistingInit = nullptr;
2998 if (StructuredIndex < StructuredList->getNumInits())
2999 ExistingInit = StructuredList->getInit(StructuredIndex);
3000
3001 if (InitListExpr *Result = dyn_cast_or_null<InitListExpr>(ExistingInit))
3002 // There might have already been initializers for subobjects of the current
3003 // object, but a subsequent initializer list will overwrite the entirety
3004 // of the current object. (See DR 253 and C99 6.7.8p21). e.g.,
3005 //
3006 // struct P { char x[6]; };
3007 // struct P l = { .x[2] = 'x', .x = { [0] = 'f' } };
3008 //
3009 // The first designated initializer is ignored, and l.x is just "f".
3010 if (!IsFullyOverwritten)
3011 return Result;
3012
3013 if (ExistingInit) {
3014 // We are creating an initializer list that initializes the
3015 // subobjects of the current object, but there was already an
3016 // initialization that completely initialized the current
3017 // subobject:
3018 //
3019 // struct X { int a, b; };
3020 // struct X xs[] = { [0] = { 1, 2 }, [0].b = 3 };
3021 //
3022 // Here, xs[0].a == 1 and xs[0].b == 3, since the second,
3023 // designated initializer overwrites the [0].b initializer
3024 // from the prior initialization.
3025 //
3026 // When the existing initializer is an expression rather than an
3027 // initializer list, we cannot decompose and update it in this way.
3028 // For example:
3029 //
3030 // struct X xs[] = { [0] = (struct X) { 1, 2 }, [0].b = 3 };
3031 //
3032 // This case is handled by CheckDesignatedInitializer.
3033 diagnoseInitOverride(ExistingInit, InitRange);
3034 }
3035
3036 unsigned ExpectedNumInits = 0;
3037 if (Index < IList->getNumInits()) {
3038 if (auto *Init = dyn_cast_or_null<InitListExpr>(IList->getInit(Index)))
3039 ExpectedNumInits = Init->getNumInits();
3040 else
3041 ExpectedNumInits = IList->getNumInits() - Index;
3042 }
3043
3044 InitListExpr *Result =
3045 createInitListExpr(CurrentObjectType, InitRange, ExpectedNumInits);
3046
3047 // Link this new initializer list into the structured initializer
3048 // lists.
3049 StructuredList->updateInit(SemaRef.Context, StructuredIndex, Result);
3050 return Result;
3051 }
3052
3053 InitListExpr *
createInitListExpr(QualType CurrentObjectType,SourceRange InitRange,unsigned ExpectedNumInits)3054 InitListChecker::createInitListExpr(QualType CurrentObjectType,
3055 SourceRange InitRange,
3056 unsigned ExpectedNumInits) {
3057 InitListExpr *Result
3058 = new (SemaRef.Context) InitListExpr(SemaRef.Context,
3059 InitRange.getBegin(), None,
3060 InitRange.getEnd());
3061
3062 QualType ResultType = CurrentObjectType;
3063 if (!ResultType->isArrayType())
3064 ResultType = ResultType.getNonLValueExprType(SemaRef.Context);
3065 Result->setType(ResultType);
3066
3067 // Pre-allocate storage for the structured initializer list.
3068 unsigned NumElements = 0;
3069
3070 if (const ArrayType *AType
3071 = SemaRef.Context.getAsArrayType(CurrentObjectType)) {
3072 if (const ConstantArrayType *CAType = dyn_cast<ConstantArrayType>(AType)) {
3073 NumElements = CAType->getSize().getZExtValue();
3074 // Simple heuristic so that we don't allocate a very large
3075 // initializer with many empty entries at the end.
3076 if (NumElements > ExpectedNumInits)
3077 NumElements = 0;
3078 }
3079 } else if (const VectorType *VType = CurrentObjectType->getAs<VectorType>()) {
3080 NumElements = VType->getNumElements();
3081 } else if (CurrentObjectType->isRecordType()) {
3082 NumElements = numStructUnionElements(CurrentObjectType);
3083 }
3084
3085 Result->reserveInits(SemaRef.Context, NumElements);
3086
3087 return Result;
3088 }
3089
3090 /// Update the initializer at index @p StructuredIndex within the
3091 /// structured initializer list to the value @p expr.
UpdateStructuredListElement(InitListExpr * StructuredList,unsigned & StructuredIndex,Expr * expr)3092 void InitListChecker::UpdateStructuredListElement(InitListExpr *StructuredList,
3093 unsigned &StructuredIndex,
3094 Expr *expr) {
3095 // No structured initializer list to update
3096 if (!StructuredList)
3097 return;
3098
3099 if (Expr *PrevInit = StructuredList->updateInit(SemaRef.Context,
3100 StructuredIndex, expr)) {
3101 // This initializer overwrites a previous initializer. Warn.
3102 diagnoseInitOverride(PrevInit, expr->getSourceRange());
3103 }
3104
3105 ++StructuredIndex;
3106 }
3107
3108 /// Determine whether we can perform aggregate initialization for the purposes
3109 /// of overload resolution.
CanPerformAggregateInitializationForOverloadResolution(const InitializedEntity & Entity,InitListExpr * From)3110 bool Sema::CanPerformAggregateInitializationForOverloadResolution(
3111 const InitializedEntity &Entity, InitListExpr *From) {
3112 QualType Type = Entity.getType();
3113 InitListChecker Check(*this, Entity, From, Type, /*VerifyOnly=*/true,
3114 /*TreatUnavailableAsInvalid=*/false,
3115 /*InOverloadResolution=*/true);
3116 return !Check.HadError();
3117 }
3118
3119 /// Check that the given Index expression is a valid array designator
3120 /// value. This is essentially just a wrapper around
3121 /// VerifyIntegerConstantExpression that also checks for negative values
3122 /// and produces a reasonable diagnostic if there is a
3123 /// failure. Returns the index expression, possibly with an implicit cast
3124 /// added, on success. If everything went okay, Value will receive the
3125 /// value of the constant expression.
3126 static ExprResult
CheckArrayDesignatorExpr(Sema & S,Expr * Index,llvm::APSInt & Value)3127 CheckArrayDesignatorExpr(Sema &S, Expr *Index, llvm::APSInt &Value) {
3128 SourceLocation Loc = Index->getBeginLoc();
3129
3130 // Make sure this is an integer constant expression.
3131 ExprResult Result = S.VerifyIntegerConstantExpression(Index, &Value);
3132 if (Result.isInvalid())
3133 return Result;
3134
3135 if (Value.isSigned() && Value.isNegative())
3136 return S.Diag(Loc, diag::err_array_designator_negative)
3137 << Value.toString(10) << Index->getSourceRange();
3138
3139 Value.setIsUnsigned(true);
3140 return Result;
3141 }
3142
ActOnDesignatedInitializer(Designation & Desig,SourceLocation EqualOrColonLoc,bool GNUSyntax,ExprResult Init)3143 ExprResult Sema::ActOnDesignatedInitializer(Designation &Desig,
3144 SourceLocation EqualOrColonLoc,
3145 bool GNUSyntax,
3146 ExprResult Init) {
3147 typedef DesignatedInitExpr::Designator ASTDesignator;
3148
3149 bool Invalid = false;
3150 SmallVector<ASTDesignator, 32> Designators;
3151 SmallVector<Expr *, 32> InitExpressions;
3152
3153 // Build designators and check array designator expressions.
3154 for (unsigned Idx = 0; Idx < Desig.getNumDesignators(); ++Idx) {
3155 const Designator &D = Desig.getDesignator(Idx);
3156 switch (D.getKind()) {
3157 case Designator::FieldDesignator:
3158 Designators.push_back(ASTDesignator(D.getField(), D.getDotLoc(),
3159 D.getFieldLoc()));
3160 break;
3161
3162 case Designator::ArrayDesignator: {
3163 Expr *Index = static_cast<Expr *>(D.getArrayIndex());
3164 llvm::APSInt IndexValue;
3165 if (!Index->isTypeDependent() && !Index->isValueDependent())
3166 Index = CheckArrayDesignatorExpr(*this, Index, IndexValue).get();
3167 if (!Index)
3168 Invalid = true;
3169 else {
3170 Designators.push_back(ASTDesignator(InitExpressions.size(),
3171 D.getLBracketLoc(),
3172 D.getRBracketLoc()));
3173 InitExpressions.push_back(Index);
3174 }
3175 break;
3176 }
3177
3178 case Designator::ArrayRangeDesignator: {
3179 Expr *StartIndex = static_cast<Expr *>(D.getArrayRangeStart());
3180 Expr *EndIndex = static_cast<Expr *>(D.getArrayRangeEnd());
3181 llvm::APSInt StartValue;
3182 llvm::APSInt EndValue;
3183 bool StartDependent = StartIndex->isTypeDependent() ||
3184 StartIndex->isValueDependent();
3185 bool EndDependent = EndIndex->isTypeDependent() ||
3186 EndIndex->isValueDependent();
3187 if (!StartDependent)
3188 StartIndex =
3189 CheckArrayDesignatorExpr(*this, StartIndex, StartValue).get();
3190 if (!EndDependent)
3191 EndIndex = CheckArrayDesignatorExpr(*this, EndIndex, EndValue).get();
3192
3193 if (!StartIndex || !EndIndex)
3194 Invalid = true;
3195 else {
3196 // Make sure we're comparing values with the same bit width.
3197 if (StartDependent || EndDependent) {
3198 // Nothing to compute.
3199 } else if (StartValue.getBitWidth() > EndValue.getBitWidth())
3200 EndValue = EndValue.extend(StartValue.getBitWidth());
3201 else if (StartValue.getBitWidth() < EndValue.getBitWidth())
3202 StartValue = StartValue.extend(EndValue.getBitWidth());
3203
3204 if (!StartDependent && !EndDependent && EndValue < StartValue) {
3205 Diag(D.getEllipsisLoc(), diag::err_array_designator_empty_range)
3206 << StartValue.toString(10) << EndValue.toString(10)
3207 << StartIndex->getSourceRange() << EndIndex->getSourceRange();
3208 Invalid = true;
3209 } else {
3210 Designators.push_back(ASTDesignator(InitExpressions.size(),
3211 D.getLBracketLoc(),
3212 D.getEllipsisLoc(),
3213 D.getRBracketLoc()));
3214 InitExpressions.push_back(StartIndex);
3215 InitExpressions.push_back(EndIndex);
3216 }
3217 }
3218 break;
3219 }
3220 }
3221 }
3222
3223 if (Invalid || Init.isInvalid())
3224 return ExprError();
3225
3226 // Clear out the expressions within the designation.
3227 Desig.ClearExprs(*this);
3228
3229 return DesignatedInitExpr::Create(Context, Designators, InitExpressions,
3230 EqualOrColonLoc, GNUSyntax,
3231 Init.getAs<Expr>());
3232 }
3233
3234 //===----------------------------------------------------------------------===//
3235 // Initialization entity
3236 //===----------------------------------------------------------------------===//
3237
InitializedEntity(ASTContext & Context,unsigned Index,const InitializedEntity & Parent)3238 InitializedEntity::InitializedEntity(ASTContext &Context, unsigned Index,
3239 const InitializedEntity &Parent)
3240 : Parent(&Parent), Index(Index)
3241 {
3242 if (const ArrayType *AT = Context.getAsArrayType(Parent.getType())) {
3243 Kind = EK_ArrayElement;
3244 Type = AT->getElementType();
3245 } else if (const VectorType *VT = Parent.getType()->getAs<VectorType>()) {
3246 Kind = EK_VectorElement;
3247 Type = VT->getElementType();
3248 } else {
3249 const ComplexType *CT = Parent.getType()->getAs<ComplexType>();
3250 assert(CT && "Unexpected type");
3251 Kind = EK_ComplexElement;
3252 Type = CT->getElementType();
3253 }
3254 }
3255
3256 InitializedEntity
InitializeBase(ASTContext & Context,const CXXBaseSpecifier * Base,bool IsInheritedVirtualBase,const InitializedEntity * Parent)3257 InitializedEntity::InitializeBase(ASTContext &Context,
3258 const CXXBaseSpecifier *Base,
3259 bool IsInheritedVirtualBase,
3260 const InitializedEntity *Parent) {
3261 InitializedEntity Result;
3262 Result.Kind = EK_Base;
3263 Result.Parent = Parent;
3264 Result.Base = reinterpret_cast<uintptr_t>(Base);
3265 if (IsInheritedVirtualBase)
3266 Result.Base |= 0x01;
3267
3268 Result.Type = Base->getType();
3269 return Result;
3270 }
3271
getName() const3272 DeclarationName InitializedEntity::getName() const {
3273 switch (getKind()) {
3274 case EK_Parameter:
3275 case EK_Parameter_CF_Audited: {
3276 ParmVarDecl *D = reinterpret_cast<ParmVarDecl*>(Parameter & ~0x1);
3277 return (D ? D->getDeclName() : DeclarationName());
3278 }
3279
3280 case EK_Variable:
3281 case EK_Member:
3282 case EK_Binding:
3283 return Variable.VariableOrMember->getDeclName();
3284
3285 case EK_LambdaCapture:
3286 return DeclarationName(Capture.VarID);
3287
3288 case EK_Result:
3289 case EK_StmtExprResult:
3290 case EK_Exception:
3291 case EK_New:
3292 case EK_Temporary:
3293 case EK_Base:
3294 case EK_Delegating:
3295 case EK_ArrayElement:
3296 case EK_VectorElement:
3297 case EK_ComplexElement:
3298 case EK_BlockElement:
3299 case EK_LambdaToBlockConversionBlockElement:
3300 case EK_CompoundLiteralInit:
3301 case EK_RelatedResult:
3302 return DeclarationName();
3303 }
3304
3305 llvm_unreachable("Invalid EntityKind!");
3306 }
3307
getDecl() const3308 ValueDecl *InitializedEntity::getDecl() const {
3309 switch (getKind()) {
3310 case EK_Variable:
3311 case EK_Member:
3312 case EK_Binding:
3313 return Variable.VariableOrMember;
3314
3315 case EK_Parameter:
3316 case EK_Parameter_CF_Audited:
3317 return reinterpret_cast<ParmVarDecl*>(Parameter & ~0x1);
3318
3319 case EK_Result:
3320 case EK_StmtExprResult:
3321 case EK_Exception:
3322 case EK_New:
3323 case EK_Temporary:
3324 case EK_Base:
3325 case EK_Delegating:
3326 case EK_ArrayElement:
3327 case EK_VectorElement:
3328 case EK_ComplexElement:
3329 case EK_BlockElement:
3330 case EK_LambdaToBlockConversionBlockElement:
3331 case EK_LambdaCapture:
3332 case EK_CompoundLiteralInit:
3333 case EK_RelatedResult:
3334 return nullptr;
3335 }
3336
3337 llvm_unreachable("Invalid EntityKind!");
3338 }
3339
allowsNRVO() const3340 bool InitializedEntity::allowsNRVO() const {
3341 switch (getKind()) {
3342 case EK_Result:
3343 case EK_Exception:
3344 return LocAndNRVO.NRVO;
3345
3346 case EK_StmtExprResult:
3347 case EK_Variable:
3348 case EK_Parameter:
3349 case EK_Parameter_CF_Audited:
3350 case EK_Member:
3351 case EK_Binding:
3352 case EK_New:
3353 case EK_Temporary:
3354 case EK_CompoundLiteralInit:
3355 case EK_Base:
3356 case EK_Delegating:
3357 case EK_ArrayElement:
3358 case EK_VectorElement:
3359 case EK_ComplexElement:
3360 case EK_BlockElement:
3361 case EK_LambdaToBlockConversionBlockElement:
3362 case EK_LambdaCapture:
3363 case EK_RelatedResult:
3364 break;
3365 }
3366
3367 return false;
3368 }
3369
dumpImpl(raw_ostream & OS) const3370 unsigned InitializedEntity::dumpImpl(raw_ostream &OS) const {
3371 assert(getParent() != this);
3372 unsigned Depth = getParent() ? getParent()->dumpImpl(OS) : 0;
3373 for (unsigned I = 0; I != Depth; ++I)
3374 OS << "`-";
3375
3376 switch (getKind()) {
3377 case EK_Variable: OS << "Variable"; break;
3378 case EK_Parameter: OS << "Parameter"; break;
3379 case EK_Parameter_CF_Audited: OS << "CF audited function Parameter";
3380 break;
3381 case EK_Result: OS << "Result"; break;
3382 case EK_StmtExprResult: OS << "StmtExprResult"; break;
3383 case EK_Exception: OS << "Exception"; break;
3384 case EK_Member: OS << "Member"; break;
3385 case EK_Binding: OS << "Binding"; break;
3386 case EK_New: OS << "New"; break;
3387 case EK_Temporary: OS << "Temporary"; break;
3388 case EK_CompoundLiteralInit: OS << "CompoundLiteral";break;
3389 case EK_RelatedResult: OS << "RelatedResult"; break;
3390 case EK_Base: OS << "Base"; break;
3391 case EK_Delegating: OS << "Delegating"; break;
3392 case EK_ArrayElement: OS << "ArrayElement " << Index; break;
3393 case EK_VectorElement: OS << "VectorElement " << Index; break;
3394 case EK_ComplexElement: OS << "ComplexElement " << Index; break;
3395 case EK_BlockElement: OS << "Block"; break;
3396 case EK_LambdaToBlockConversionBlockElement:
3397 OS << "Block (lambda)";
3398 break;
3399 case EK_LambdaCapture:
3400 OS << "LambdaCapture ";
3401 OS << DeclarationName(Capture.VarID);
3402 break;
3403 }
3404
3405 if (auto *D = getDecl()) {
3406 OS << " ";
3407 D->printQualifiedName(OS);
3408 }
3409
3410 OS << " '" << getType().getAsString() << "'\n";
3411
3412 return Depth + 1;
3413 }
3414
dump() const3415 LLVM_DUMP_METHOD void InitializedEntity::dump() const {
3416 dumpImpl(llvm::errs());
3417 }
3418
3419 //===----------------------------------------------------------------------===//
3420 // Initialization sequence
3421 //===----------------------------------------------------------------------===//
3422
Destroy()3423 void InitializationSequence::Step::Destroy() {
3424 switch (Kind) {
3425 case SK_ResolveAddressOfOverloadedFunction:
3426 case SK_CastDerivedToBaseRValue:
3427 case SK_CastDerivedToBaseXValue:
3428 case SK_CastDerivedToBaseLValue:
3429 case SK_BindReference:
3430 case SK_BindReferenceToTemporary:
3431 case SK_FinalCopy:
3432 case SK_ExtraneousCopyToTemporary:
3433 case SK_UserConversion:
3434 case SK_QualificationConversionRValue:
3435 case SK_QualificationConversionXValue:
3436 case SK_QualificationConversionLValue:
3437 case SK_AtomicConversion:
3438 case SK_ListInitialization:
3439 case SK_UnwrapInitList:
3440 case SK_RewrapInitList:
3441 case SK_ConstructorInitialization:
3442 case SK_ConstructorInitializationFromList:
3443 case SK_ZeroInitialization:
3444 case SK_CAssignment:
3445 case SK_StringInit:
3446 case SK_ObjCObjectConversion:
3447 case SK_ArrayLoopIndex:
3448 case SK_ArrayLoopInit:
3449 case SK_ArrayInit:
3450 case SK_GNUArrayInit:
3451 case SK_ParenthesizedArrayInit:
3452 case SK_PassByIndirectCopyRestore:
3453 case SK_PassByIndirectRestore:
3454 case SK_ProduceObjCObject:
3455 case SK_StdInitializerList:
3456 case SK_StdInitializerListConstructorCall:
3457 case SK_OCLSamplerInit:
3458 case SK_OCLZeroOpaqueType:
3459 break;
3460
3461 case SK_ConversionSequence:
3462 case SK_ConversionSequenceNoNarrowing:
3463 delete ICS;
3464 }
3465 }
3466
isDirectReferenceBinding() const3467 bool InitializationSequence::isDirectReferenceBinding() const {
3468 // There can be some lvalue adjustments after the SK_BindReference step.
3469 for (auto I = Steps.rbegin(); I != Steps.rend(); ++I) {
3470 if (I->Kind == SK_BindReference)
3471 return true;
3472 if (I->Kind == SK_BindReferenceToTemporary)
3473 return false;
3474 }
3475 return false;
3476 }
3477
isAmbiguous() const3478 bool InitializationSequence::isAmbiguous() const {
3479 if (!Failed())
3480 return false;
3481
3482 switch (getFailureKind()) {
3483 case FK_TooManyInitsForReference:
3484 case FK_ParenthesizedListInitForReference:
3485 case FK_ArrayNeedsInitList:
3486 case FK_ArrayNeedsInitListOrStringLiteral:
3487 case FK_ArrayNeedsInitListOrWideStringLiteral:
3488 case FK_NarrowStringIntoWideCharArray:
3489 case FK_WideStringIntoCharArray:
3490 case FK_IncompatWideStringIntoWideChar:
3491 case FK_PlainStringIntoUTF8Char:
3492 case FK_UTF8StringIntoPlainChar:
3493 case FK_AddressOfOverloadFailed: // FIXME: Could do better
3494 case FK_NonConstLValueReferenceBindingToTemporary:
3495 case FK_NonConstLValueReferenceBindingToBitfield:
3496 case FK_NonConstLValueReferenceBindingToVectorElement:
3497 case FK_NonConstLValueReferenceBindingToMatrixElement:
3498 case FK_NonConstLValueReferenceBindingToUnrelated:
3499 case FK_RValueReferenceBindingToLValue:
3500 case FK_ReferenceAddrspaceMismatchTemporary:
3501 case FK_ReferenceInitDropsQualifiers:
3502 case FK_ReferenceInitFailed:
3503 case FK_ConversionFailed:
3504 case FK_ConversionFromPropertyFailed:
3505 case FK_TooManyInitsForScalar:
3506 case FK_ParenthesizedListInitForScalar:
3507 case FK_ReferenceBindingToInitList:
3508 case FK_InitListBadDestinationType:
3509 case FK_DefaultInitOfConst:
3510 case FK_Incomplete:
3511 case FK_ArrayTypeMismatch:
3512 case FK_NonConstantArrayInit:
3513 case FK_ListInitializationFailed:
3514 case FK_VariableLengthArrayHasInitializer:
3515 case FK_PlaceholderType:
3516 case FK_ExplicitConstructor:
3517 case FK_AddressOfUnaddressableFunction:
3518 return false;
3519
3520 case FK_ReferenceInitOverloadFailed:
3521 case FK_UserConversionOverloadFailed:
3522 case FK_ConstructorOverloadFailed:
3523 case FK_ListConstructorOverloadFailed:
3524 return FailedOverloadResult == OR_Ambiguous;
3525 }
3526
3527 llvm_unreachable("Invalid EntityKind!");
3528 }
3529
isConstructorInitialization() const3530 bool InitializationSequence::isConstructorInitialization() const {
3531 return !Steps.empty() && Steps.back().Kind == SK_ConstructorInitialization;
3532 }
3533
3534 void
3535 InitializationSequence
AddAddressOverloadResolutionStep(FunctionDecl * Function,DeclAccessPair Found,bool HadMultipleCandidates)3536 ::AddAddressOverloadResolutionStep(FunctionDecl *Function,
3537 DeclAccessPair Found,
3538 bool HadMultipleCandidates) {
3539 Step S;
3540 S.Kind = SK_ResolveAddressOfOverloadedFunction;
3541 S.Type = Function->getType();
3542 S.Function.HadMultipleCandidates = HadMultipleCandidates;
3543 S.Function.Function = Function;
3544 S.Function.FoundDecl = Found;
3545 Steps.push_back(S);
3546 }
3547
AddDerivedToBaseCastStep(QualType BaseType,ExprValueKind VK)3548 void InitializationSequence::AddDerivedToBaseCastStep(QualType BaseType,
3549 ExprValueKind VK) {
3550 Step S;
3551 switch (VK) {
3552 case VK_RValue: S.Kind = SK_CastDerivedToBaseRValue; break;
3553 case VK_XValue: S.Kind = SK_CastDerivedToBaseXValue; break;
3554 case VK_LValue: S.Kind = SK_CastDerivedToBaseLValue; break;
3555 }
3556 S.Type = BaseType;
3557 Steps.push_back(S);
3558 }
3559
AddReferenceBindingStep(QualType T,bool BindingTemporary)3560 void InitializationSequence::AddReferenceBindingStep(QualType T,
3561 bool BindingTemporary) {
3562 Step S;
3563 S.Kind = BindingTemporary? SK_BindReferenceToTemporary : SK_BindReference;
3564 S.Type = T;
3565 Steps.push_back(S);
3566 }
3567
AddFinalCopy(QualType T)3568 void InitializationSequence::AddFinalCopy(QualType T) {
3569 Step S;
3570 S.Kind = SK_FinalCopy;
3571 S.Type = T;
3572 Steps.push_back(S);
3573 }
3574
AddExtraneousCopyToTemporary(QualType T)3575 void InitializationSequence::AddExtraneousCopyToTemporary(QualType T) {
3576 Step S;
3577 S.Kind = SK_ExtraneousCopyToTemporary;
3578 S.Type = T;
3579 Steps.push_back(S);
3580 }
3581
3582 void
AddUserConversionStep(FunctionDecl * Function,DeclAccessPair FoundDecl,QualType T,bool HadMultipleCandidates)3583 InitializationSequence::AddUserConversionStep(FunctionDecl *Function,
3584 DeclAccessPair FoundDecl,
3585 QualType T,
3586 bool HadMultipleCandidates) {
3587 Step S;
3588 S.Kind = SK_UserConversion;
3589 S.Type = T;
3590 S.Function.HadMultipleCandidates = HadMultipleCandidates;
3591 S.Function.Function = Function;
3592 S.Function.FoundDecl = FoundDecl;
3593 Steps.push_back(S);
3594 }
3595
AddQualificationConversionStep(QualType Ty,ExprValueKind VK)3596 void InitializationSequence::AddQualificationConversionStep(QualType Ty,
3597 ExprValueKind VK) {
3598 Step S;
3599 S.Kind = SK_QualificationConversionRValue; // work around a gcc warning
3600 switch (VK) {
3601 case VK_RValue:
3602 S.Kind = SK_QualificationConversionRValue;
3603 break;
3604 case VK_XValue:
3605 S.Kind = SK_QualificationConversionXValue;
3606 break;
3607 case VK_LValue:
3608 S.Kind = SK_QualificationConversionLValue;
3609 break;
3610 }
3611 S.Type = Ty;
3612 Steps.push_back(S);
3613 }
3614
AddAtomicConversionStep(QualType Ty)3615 void InitializationSequence::AddAtomicConversionStep(QualType Ty) {
3616 Step S;
3617 S.Kind = SK_AtomicConversion;
3618 S.Type = Ty;
3619 Steps.push_back(S);
3620 }
3621
AddConversionSequenceStep(const ImplicitConversionSequence & ICS,QualType T,bool TopLevelOfInitList)3622 void InitializationSequence::AddConversionSequenceStep(
3623 const ImplicitConversionSequence &ICS, QualType T,
3624 bool TopLevelOfInitList) {
3625 Step S;
3626 S.Kind = TopLevelOfInitList ? SK_ConversionSequenceNoNarrowing
3627 : SK_ConversionSequence;
3628 S.Type = T;
3629 S.ICS = new ImplicitConversionSequence(ICS);
3630 Steps.push_back(S);
3631 }
3632
AddListInitializationStep(QualType T)3633 void InitializationSequence::AddListInitializationStep(QualType T) {
3634 Step S;
3635 S.Kind = SK_ListInitialization;
3636 S.Type = T;
3637 Steps.push_back(S);
3638 }
3639
AddConstructorInitializationStep(DeclAccessPair FoundDecl,CXXConstructorDecl * Constructor,QualType T,bool HadMultipleCandidates,bool FromInitList,bool AsInitList)3640 void InitializationSequence::AddConstructorInitializationStep(
3641 DeclAccessPair FoundDecl, CXXConstructorDecl *Constructor, QualType T,
3642 bool HadMultipleCandidates, bool FromInitList, bool AsInitList) {
3643 Step S;
3644 S.Kind = FromInitList ? AsInitList ? SK_StdInitializerListConstructorCall
3645 : SK_ConstructorInitializationFromList
3646 : SK_ConstructorInitialization;
3647 S.Type = T;
3648 S.Function.HadMultipleCandidates = HadMultipleCandidates;
3649 S.Function.Function = Constructor;
3650 S.Function.FoundDecl = FoundDecl;
3651 Steps.push_back(S);
3652 }
3653
AddZeroInitializationStep(QualType T)3654 void InitializationSequence::AddZeroInitializationStep(QualType T) {
3655 Step S;
3656 S.Kind = SK_ZeroInitialization;
3657 S.Type = T;
3658 Steps.push_back(S);
3659 }
3660
AddCAssignmentStep(QualType T)3661 void InitializationSequence::AddCAssignmentStep(QualType T) {
3662 Step S;
3663 S.Kind = SK_CAssignment;
3664 S.Type = T;
3665 Steps.push_back(S);
3666 }
3667
AddStringInitStep(QualType T)3668 void InitializationSequence::AddStringInitStep(QualType T) {
3669 Step S;
3670 S.Kind = SK_StringInit;
3671 S.Type = T;
3672 Steps.push_back(S);
3673 }
3674
AddObjCObjectConversionStep(QualType T)3675 void InitializationSequence::AddObjCObjectConversionStep(QualType T) {
3676 Step S;
3677 S.Kind = SK_ObjCObjectConversion;
3678 S.Type = T;
3679 Steps.push_back(S);
3680 }
3681
AddArrayInitStep(QualType T,bool IsGNUExtension)3682 void InitializationSequence::AddArrayInitStep(QualType T, bool IsGNUExtension) {
3683 Step S;
3684 S.Kind = IsGNUExtension ? SK_GNUArrayInit : SK_ArrayInit;
3685 S.Type = T;
3686 Steps.push_back(S);
3687 }
3688
AddArrayInitLoopStep(QualType T,QualType EltT)3689 void InitializationSequence::AddArrayInitLoopStep(QualType T, QualType EltT) {
3690 Step S;
3691 S.Kind = SK_ArrayLoopIndex;
3692 S.Type = EltT;
3693 Steps.insert(Steps.begin(), S);
3694
3695 S.Kind = SK_ArrayLoopInit;
3696 S.Type = T;
3697 Steps.push_back(S);
3698 }
3699
AddParenthesizedArrayInitStep(QualType T)3700 void InitializationSequence::AddParenthesizedArrayInitStep(QualType T) {
3701 Step S;
3702 S.Kind = SK_ParenthesizedArrayInit;
3703 S.Type = T;
3704 Steps.push_back(S);
3705 }
3706
AddPassByIndirectCopyRestoreStep(QualType type,bool shouldCopy)3707 void InitializationSequence::AddPassByIndirectCopyRestoreStep(QualType type,
3708 bool shouldCopy) {
3709 Step s;
3710 s.Kind = (shouldCopy ? SK_PassByIndirectCopyRestore
3711 : SK_PassByIndirectRestore);
3712 s.Type = type;
3713 Steps.push_back(s);
3714 }
3715
AddProduceObjCObjectStep(QualType T)3716 void InitializationSequence::AddProduceObjCObjectStep(QualType T) {
3717 Step S;
3718 S.Kind = SK_ProduceObjCObject;
3719 S.Type = T;
3720 Steps.push_back(S);
3721 }
3722
AddStdInitializerListConstructionStep(QualType T)3723 void InitializationSequence::AddStdInitializerListConstructionStep(QualType T) {
3724 Step S;
3725 S.Kind = SK_StdInitializerList;
3726 S.Type = T;
3727 Steps.push_back(S);
3728 }
3729
AddOCLSamplerInitStep(QualType T)3730 void InitializationSequence::AddOCLSamplerInitStep(QualType T) {
3731 Step S;
3732 S.Kind = SK_OCLSamplerInit;
3733 S.Type = T;
3734 Steps.push_back(S);
3735 }
3736
AddOCLZeroOpaqueTypeStep(QualType T)3737 void InitializationSequence::AddOCLZeroOpaqueTypeStep(QualType T) {
3738 Step S;
3739 S.Kind = SK_OCLZeroOpaqueType;
3740 S.Type = T;
3741 Steps.push_back(S);
3742 }
3743
RewrapReferenceInitList(QualType T,InitListExpr * Syntactic)3744 void InitializationSequence::RewrapReferenceInitList(QualType T,
3745 InitListExpr *Syntactic) {
3746 assert(Syntactic->getNumInits() == 1 &&
3747 "Can only rewrap trivial init lists.");
3748 Step S;
3749 S.Kind = SK_UnwrapInitList;
3750 S.Type = Syntactic->getInit(0)->getType();
3751 Steps.insert(Steps.begin(), S);
3752
3753 S.Kind = SK_RewrapInitList;
3754 S.Type = T;
3755 S.WrappingSyntacticList = Syntactic;
3756 Steps.push_back(S);
3757 }
3758
SetOverloadFailure(FailureKind Failure,OverloadingResult Result)3759 void InitializationSequence::SetOverloadFailure(FailureKind Failure,
3760 OverloadingResult Result) {
3761 setSequenceKind(FailedSequence);
3762 this->Failure = Failure;
3763 this->FailedOverloadResult = Result;
3764 }
3765
3766 //===----------------------------------------------------------------------===//
3767 // Attempt initialization
3768 //===----------------------------------------------------------------------===//
3769
3770 /// Tries to add a zero initializer. Returns true if that worked.
3771 static bool
maybeRecoverWithZeroInitialization(Sema & S,InitializationSequence & Sequence,const InitializedEntity & Entity)3772 maybeRecoverWithZeroInitialization(Sema &S, InitializationSequence &Sequence,
3773 const InitializedEntity &Entity) {
3774 if (Entity.getKind() != InitializedEntity::EK_Variable)
3775 return false;
3776
3777 VarDecl *VD = cast<VarDecl>(Entity.getDecl());
3778 if (VD->getInit() || VD->getEndLoc().isMacroID())
3779 return false;
3780
3781 QualType VariableTy = VD->getType().getCanonicalType();
3782 SourceLocation Loc = S.getLocForEndOfToken(VD->getEndLoc());
3783 std::string Init = S.getFixItZeroInitializerForType(VariableTy, Loc);
3784 if (!Init.empty()) {
3785 Sequence.AddZeroInitializationStep(Entity.getType());
3786 Sequence.SetZeroInitializationFixit(Init, Loc);
3787 return true;
3788 }
3789 return false;
3790 }
3791
MaybeProduceObjCObject(Sema & S,InitializationSequence & Sequence,const InitializedEntity & Entity)3792 static void MaybeProduceObjCObject(Sema &S,
3793 InitializationSequence &Sequence,
3794 const InitializedEntity &Entity) {
3795 if (!S.getLangOpts().ObjCAutoRefCount) return;
3796
3797 /// When initializing a parameter, produce the value if it's marked
3798 /// __attribute__((ns_consumed)).
3799 if (Entity.isParameterKind()) {
3800 if (!Entity.isParameterConsumed())
3801 return;
3802
3803 assert(Entity.getType()->isObjCRetainableType() &&
3804 "consuming an object of unretainable type?");
3805 Sequence.AddProduceObjCObjectStep(Entity.getType());
3806
3807 /// When initializing a return value, if the return type is a
3808 /// retainable type, then returns need to immediately retain the
3809 /// object. If an autorelease is required, it will be done at the
3810 /// last instant.
3811 } else if (Entity.getKind() == InitializedEntity::EK_Result ||
3812 Entity.getKind() == InitializedEntity::EK_StmtExprResult) {
3813 if (!Entity.getType()->isObjCRetainableType())
3814 return;
3815
3816 Sequence.AddProduceObjCObjectStep(Entity.getType());
3817 }
3818 }
3819
3820 static void TryListInitialization(Sema &S,
3821 const InitializedEntity &Entity,
3822 const InitializationKind &Kind,
3823 InitListExpr *InitList,
3824 InitializationSequence &Sequence,
3825 bool TreatUnavailableAsInvalid);
3826
3827 /// When initializing from init list via constructor, handle
3828 /// initialization of an object of type std::initializer_list<T>.
3829 ///
3830 /// \return true if we have handled initialization of an object of type
3831 /// std::initializer_list<T>, false otherwise.
TryInitializerListConstruction(Sema & S,InitListExpr * List,QualType DestType,InitializationSequence & Sequence,bool TreatUnavailableAsInvalid)3832 static bool TryInitializerListConstruction(Sema &S,
3833 InitListExpr *List,
3834 QualType DestType,
3835 InitializationSequence &Sequence,
3836 bool TreatUnavailableAsInvalid) {
3837 QualType E;
3838 if (!S.isStdInitializerList(DestType, &E))
3839 return false;
3840
3841 if (!S.isCompleteType(List->getExprLoc(), E)) {
3842 Sequence.setIncompleteTypeFailure(E);
3843 return true;
3844 }
3845
3846 // Try initializing a temporary array from the init list.
3847 QualType ArrayType = S.Context.getConstantArrayType(
3848 E.withConst(),
3849 llvm::APInt(S.Context.getTypeSize(S.Context.getSizeType()),
3850 List->getNumInits()),
3851 nullptr, clang::ArrayType::Normal, 0);
3852 InitializedEntity HiddenArray =
3853 InitializedEntity::InitializeTemporary(ArrayType);
3854 InitializationKind Kind = InitializationKind::CreateDirectList(
3855 List->getExprLoc(), List->getBeginLoc(), List->getEndLoc());
3856 TryListInitialization(S, HiddenArray, Kind, List, Sequence,
3857 TreatUnavailableAsInvalid);
3858 if (Sequence)
3859 Sequence.AddStdInitializerListConstructionStep(DestType);
3860 return true;
3861 }
3862
3863 /// Determine if the constructor has the signature of a copy or move
3864 /// constructor for the type T of the class in which it was found. That is,
3865 /// determine if its first parameter is of type T or reference to (possibly
3866 /// cv-qualified) T.
hasCopyOrMoveCtorParam(ASTContext & Ctx,const ConstructorInfo & Info)3867 static bool hasCopyOrMoveCtorParam(ASTContext &Ctx,
3868 const ConstructorInfo &Info) {
3869 if (Info.Constructor->getNumParams() == 0)
3870 return false;
3871
3872 QualType ParmT =
3873 Info.Constructor->getParamDecl(0)->getType().getNonReferenceType();
3874 QualType ClassT =
3875 Ctx.getRecordType(cast<CXXRecordDecl>(Info.FoundDecl->getDeclContext()));
3876
3877 return Ctx.hasSameUnqualifiedType(ParmT, ClassT);
3878 }
3879
3880 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)3881 ResolveConstructorOverload(Sema &S, SourceLocation DeclLoc,
3882 MultiExprArg Args,
3883 OverloadCandidateSet &CandidateSet,
3884 QualType DestType,
3885 DeclContext::lookup_result Ctors,
3886 OverloadCandidateSet::iterator &Best,
3887 bool CopyInitializing, bool AllowExplicit,
3888 bool OnlyListConstructors, bool IsListInit,
3889 bool SecondStepOfCopyInit = false) {
3890 CandidateSet.clear(OverloadCandidateSet::CSK_InitByConstructor);
3891 CandidateSet.setDestAS(DestType.getQualifiers().getAddressSpace());
3892
3893 for (NamedDecl *D : Ctors) {
3894 auto Info = getConstructorInfo(D);
3895 if (!Info.Constructor || Info.Constructor->isInvalidDecl())
3896 continue;
3897
3898 if (OnlyListConstructors && !S.isInitListConstructor(Info.Constructor))
3899 continue;
3900
3901 // C++11 [over.best.ics]p4:
3902 // ... and the constructor or user-defined conversion function is a
3903 // candidate by
3904 // - 13.3.1.3, when the argument is the temporary in the second step
3905 // of a class copy-initialization, or
3906 // - 13.3.1.4, 13.3.1.5, or 13.3.1.6 (in all cases), [not handled here]
3907 // - the second phase of 13.3.1.7 when the initializer list has exactly
3908 // one element that is itself an initializer list, and the target is
3909 // the first parameter of a constructor of class X, and the conversion
3910 // is to X or reference to (possibly cv-qualified X),
3911 // user-defined conversion sequences are not considered.
3912 bool SuppressUserConversions =
3913 SecondStepOfCopyInit ||
3914 (IsListInit && Args.size() == 1 && isa<InitListExpr>(Args[0]) &&
3915 hasCopyOrMoveCtorParam(S.Context, Info));
3916
3917 if (Info.ConstructorTmpl)
3918 S.AddTemplateOverloadCandidate(
3919 Info.ConstructorTmpl, Info.FoundDecl,
3920 /*ExplicitArgs*/ nullptr, Args, CandidateSet, SuppressUserConversions,
3921 /*PartialOverloading=*/false, AllowExplicit);
3922 else {
3923 // C++ [over.match.copy]p1:
3924 // - When initializing a temporary to be bound to the first parameter
3925 // of a constructor [for type T] that takes a reference to possibly
3926 // cv-qualified T as its first argument, called with a single
3927 // argument in the context of direct-initialization, explicit
3928 // conversion functions are also considered.
3929 // FIXME: What if a constructor template instantiates to such a signature?
3930 bool AllowExplicitConv = AllowExplicit && !CopyInitializing &&
3931 Args.size() == 1 &&
3932 hasCopyOrMoveCtorParam(S.Context, Info);
3933 S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, Args,
3934 CandidateSet, SuppressUserConversions,
3935 /*PartialOverloading=*/false, AllowExplicit,
3936 AllowExplicitConv);
3937 }
3938 }
3939
3940 // FIXME: Work around a bug in C++17 guaranteed copy elision.
3941 //
3942 // When initializing an object of class type T by constructor
3943 // ([over.match.ctor]) or by list-initialization ([over.match.list])
3944 // from a single expression of class type U, conversion functions of
3945 // U that convert to the non-reference type cv T are candidates.
3946 // Explicit conversion functions are only candidates during
3947 // direct-initialization.
3948 //
3949 // Note: SecondStepOfCopyInit is only ever true in this case when
3950 // evaluating whether to produce a C++98 compatibility warning.
3951 if (S.getLangOpts().CPlusPlus17 && Args.size() == 1 &&
3952 !SecondStepOfCopyInit) {
3953 Expr *Initializer = Args[0];
3954 auto *SourceRD = Initializer->getType()->getAsCXXRecordDecl();
3955 if (SourceRD && S.isCompleteType(DeclLoc, Initializer->getType())) {
3956 const auto &Conversions = SourceRD->getVisibleConversionFunctions();
3957 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
3958 NamedDecl *D = *I;
3959 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
3960 D = D->getUnderlyingDecl();
3961
3962 FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
3963 CXXConversionDecl *Conv;
3964 if (ConvTemplate)
3965 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
3966 else
3967 Conv = cast<CXXConversionDecl>(D);
3968
3969 if (ConvTemplate)
3970 S.AddTemplateConversionCandidate(
3971 ConvTemplate, I.getPair(), ActingDC, Initializer, DestType,
3972 CandidateSet, AllowExplicit, AllowExplicit,
3973 /*AllowResultConversion*/ false);
3974 else
3975 S.AddConversionCandidate(Conv, I.getPair(), ActingDC, Initializer,
3976 DestType, CandidateSet, AllowExplicit,
3977 AllowExplicit,
3978 /*AllowResultConversion*/ false);
3979 }
3980 }
3981 }
3982
3983 // Perform overload resolution and return the result.
3984 return CandidateSet.BestViableFunction(S, DeclLoc, Best);
3985 }
3986
3987 /// Attempt initialization by constructor (C++ [dcl.init]), which
3988 /// enumerates the constructors of the initialized entity and performs overload
3989 /// resolution to select the best.
3990 /// \param DestType The destination class type.
3991 /// \param DestArrayType The destination type, which is either DestType or
3992 /// a (possibly multidimensional) array of DestType.
3993 /// \param IsListInit Is this list-initialization?
3994 /// \param IsInitListCopy Is this non-list-initialization resulting from a
3995 /// list-initialization from {x} where x is the same
3996 /// 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)3997 static void TryConstructorInitialization(Sema &S,
3998 const InitializedEntity &Entity,
3999 const InitializationKind &Kind,
4000 MultiExprArg Args, QualType DestType,
4001 QualType DestArrayType,
4002 InitializationSequence &Sequence,
4003 bool IsListInit = false,
4004 bool IsInitListCopy = false) {
4005 assert(((!IsListInit && !IsInitListCopy) ||
4006 (Args.size() == 1 && isa<InitListExpr>(Args[0]))) &&
4007 "IsListInit/IsInitListCopy must come with a single initializer list "
4008 "argument.");
4009 InitListExpr *ILE =
4010 (IsListInit || IsInitListCopy) ? cast<InitListExpr>(Args[0]) : nullptr;
4011 MultiExprArg UnwrappedArgs =
4012 ILE ? MultiExprArg(ILE->getInits(), ILE->getNumInits()) : Args;
4013
4014 // The type we're constructing needs to be complete.
4015 if (!S.isCompleteType(Kind.getLocation(), DestType)) {
4016 Sequence.setIncompleteTypeFailure(DestType);
4017 return;
4018 }
4019
4020 // C++17 [dcl.init]p17:
4021 // - If the initializer expression is a prvalue and the cv-unqualified
4022 // version of the source type is the same class as the class of the
4023 // destination, the initializer expression is used to initialize the
4024 // destination object.
4025 // Per DR (no number yet), this does not apply when initializing a base
4026 // class or delegating to another constructor from a mem-initializer.
4027 // ObjC++: Lambda captured by the block in the lambda to block conversion
4028 // should avoid copy elision.
4029 if (S.getLangOpts().CPlusPlus17 &&
4030 Entity.getKind() != InitializedEntity::EK_Base &&
4031 Entity.getKind() != InitializedEntity::EK_Delegating &&
4032 Entity.getKind() !=
4033 InitializedEntity::EK_LambdaToBlockConversionBlockElement &&
4034 UnwrappedArgs.size() == 1 && UnwrappedArgs[0]->isRValue() &&
4035 S.Context.hasSameUnqualifiedType(UnwrappedArgs[0]->getType(), DestType)) {
4036 // Convert qualifications if necessary.
4037 Sequence.AddQualificationConversionStep(DestType, VK_RValue);
4038 if (ILE)
4039 Sequence.RewrapReferenceInitList(DestType, ILE);
4040 return;
4041 }
4042
4043 const RecordType *DestRecordType = DestType->getAs<RecordType>();
4044 assert(DestRecordType && "Constructor initialization requires record type");
4045 CXXRecordDecl *DestRecordDecl
4046 = cast<CXXRecordDecl>(DestRecordType->getDecl());
4047
4048 // Build the candidate set directly in the initialization sequence
4049 // structure, so that it will persist if we fail.
4050 OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
4051
4052 // Determine whether we are allowed to call explicit constructors or
4053 // explicit conversion operators.
4054 bool AllowExplicit = Kind.AllowExplicit() || IsListInit;
4055 bool CopyInitialization = Kind.getKind() == InitializationKind::IK_Copy;
4056
4057 // - Otherwise, if T is a class type, constructors are considered. The
4058 // applicable constructors are enumerated, and the best one is chosen
4059 // through overload resolution.
4060 DeclContext::lookup_result Ctors = S.LookupConstructors(DestRecordDecl);
4061
4062 OverloadingResult Result = OR_No_Viable_Function;
4063 OverloadCandidateSet::iterator Best;
4064 bool AsInitializerList = false;
4065
4066 // C++11 [over.match.list]p1, per DR1467:
4067 // When objects of non-aggregate type T are list-initialized, such that
4068 // 8.5.4 [dcl.init.list] specifies that overload resolution is performed
4069 // according to the rules in this section, overload resolution selects
4070 // the constructor in two phases:
4071 //
4072 // - Initially, the candidate functions are the initializer-list
4073 // constructors of the class T and the argument list consists of the
4074 // initializer list as a single argument.
4075 if (IsListInit) {
4076 AsInitializerList = true;
4077
4078 // If the initializer list has no elements and T has a default constructor,
4079 // the first phase is omitted.
4080 if (!(UnwrappedArgs.empty() && S.LookupDefaultConstructor(DestRecordDecl)))
4081 Result = ResolveConstructorOverload(S, Kind.getLocation(), Args,
4082 CandidateSet, DestType, Ctors, Best,
4083 CopyInitialization, AllowExplicit,
4084 /*OnlyListConstructors=*/true,
4085 IsListInit);
4086 }
4087
4088 // C++11 [over.match.list]p1:
4089 // - If no viable initializer-list constructor is found, overload resolution
4090 // is performed again, where the candidate functions are all the
4091 // constructors of the class T and the argument list consists of the
4092 // elements of the initializer list.
4093 if (Result == OR_No_Viable_Function) {
4094 AsInitializerList = false;
4095 Result = ResolveConstructorOverload(S, Kind.getLocation(), UnwrappedArgs,
4096 CandidateSet, DestType, Ctors, Best,
4097 CopyInitialization, AllowExplicit,
4098 /*OnlyListConstructors=*/false,
4099 IsListInit);
4100 }
4101 if (Result) {
4102 Sequence.SetOverloadFailure(IsListInit ?
4103 InitializationSequence::FK_ListConstructorOverloadFailed :
4104 InitializationSequence::FK_ConstructorOverloadFailed,
4105 Result);
4106 return;
4107 }
4108
4109 bool HadMultipleCandidates = (CandidateSet.size() > 1);
4110
4111 // In C++17, ResolveConstructorOverload can select a conversion function
4112 // instead of a constructor.
4113 if (auto *CD = dyn_cast<CXXConversionDecl>(Best->Function)) {
4114 // Add the user-defined conversion step that calls the conversion function.
4115 QualType ConvType = CD->getConversionType();
4116 assert(S.Context.hasSameUnqualifiedType(ConvType, DestType) &&
4117 "should not have selected this conversion function");
4118 Sequence.AddUserConversionStep(CD, Best->FoundDecl, ConvType,
4119 HadMultipleCandidates);
4120 if (!S.Context.hasSameType(ConvType, DestType))
4121 Sequence.AddQualificationConversionStep(DestType, VK_RValue);
4122 if (IsListInit)
4123 Sequence.RewrapReferenceInitList(Entity.getType(), ILE);
4124 return;
4125 }
4126
4127 // C++11 [dcl.init]p6:
4128 // If a program calls for the default initialization of an object
4129 // of a const-qualified type T, T shall be a class type with a
4130 // user-provided default constructor.
4131 // C++ core issue 253 proposal:
4132 // If the implicit default constructor initializes all subobjects, no
4133 // initializer should be required.
4134 // The 253 proposal is for example needed to process libstdc++ headers in 5.x.
4135 CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
4136 if (Kind.getKind() == InitializationKind::IK_Default &&
4137 Entity.getType().isConstQualified()) {
4138 if (!CtorDecl->getParent()->allowConstDefaultInit()) {
4139 if (!maybeRecoverWithZeroInitialization(S, Sequence, Entity))
4140 Sequence.SetFailed(InitializationSequence::FK_DefaultInitOfConst);
4141 return;
4142 }
4143 }
4144
4145 // C++11 [over.match.list]p1:
4146 // In copy-list-initialization, if an explicit constructor is chosen, the
4147 // initializer is ill-formed.
4148 if (IsListInit && !Kind.AllowExplicit() && CtorDecl->isExplicit()) {
4149 Sequence.SetFailed(InitializationSequence::FK_ExplicitConstructor);
4150 return;
4151 }
4152
4153 // Add the constructor initialization step. Any cv-qualification conversion is
4154 // subsumed by the initialization.
4155 Sequence.AddConstructorInitializationStep(
4156 Best->FoundDecl, CtorDecl, DestArrayType, HadMultipleCandidates,
4157 IsListInit | IsInitListCopy, AsInitializerList);
4158 }
4159
4160 static bool
ResolveOverloadedFunctionForReferenceBinding(Sema & S,Expr * Initializer,QualType & SourceType,QualType & UnqualifiedSourceType,QualType UnqualifiedTargetType,InitializationSequence & Sequence)4161 ResolveOverloadedFunctionForReferenceBinding(Sema &S,
4162 Expr *Initializer,
4163 QualType &SourceType,
4164 QualType &UnqualifiedSourceType,
4165 QualType UnqualifiedTargetType,
4166 InitializationSequence &Sequence) {
4167 if (S.Context.getCanonicalType(UnqualifiedSourceType) ==
4168 S.Context.OverloadTy) {
4169 DeclAccessPair Found;
4170 bool HadMultipleCandidates = false;
4171 if (FunctionDecl *Fn
4172 = S.ResolveAddressOfOverloadedFunction(Initializer,
4173 UnqualifiedTargetType,
4174 false, Found,
4175 &HadMultipleCandidates)) {
4176 Sequence.AddAddressOverloadResolutionStep(Fn, Found,
4177 HadMultipleCandidates);
4178 SourceType = Fn->getType();
4179 UnqualifiedSourceType = SourceType.getUnqualifiedType();
4180 } else if (!UnqualifiedTargetType->isRecordType()) {
4181 Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
4182 return true;
4183 }
4184 }
4185 return false;
4186 }
4187
4188 static void TryReferenceInitializationCore(Sema &S,
4189 const InitializedEntity &Entity,
4190 const InitializationKind &Kind,
4191 Expr *Initializer,
4192 QualType cv1T1, QualType T1,
4193 Qualifiers T1Quals,
4194 QualType cv2T2, QualType T2,
4195 Qualifiers T2Quals,
4196 InitializationSequence &Sequence);
4197
4198 static void TryValueInitialization(Sema &S,
4199 const InitializedEntity &Entity,
4200 const InitializationKind &Kind,
4201 InitializationSequence &Sequence,
4202 InitListExpr *InitList = nullptr);
4203
4204 /// Attempt list initialization of a reference.
TryReferenceListInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,InitListExpr * InitList,InitializationSequence & Sequence,bool TreatUnavailableAsInvalid)4205 static void TryReferenceListInitialization(Sema &S,
4206 const InitializedEntity &Entity,
4207 const InitializationKind &Kind,
4208 InitListExpr *InitList,
4209 InitializationSequence &Sequence,
4210 bool TreatUnavailableAsInvalid) {
4211 // First, catch C++03 where this isn't possible.
4212 if (!S.getLangOpts().CPlusPlus11) {
4213 Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
4214 return;
4215 }
4216 // Can't reference initialize a compound literal.
4217 if (Entity.getKind() == InitializedEntity::EK_CompoundLiteralInit) {
4218 Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
4219 return;
4220 }
4221
4222 QualType DestType = Entity.getType();
4223 QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
4224 Qualifiers T1Quals;
4225 QualType T1 = S.Context.getUnqualifiedArrayType(cv1T1, T1Quals);
4226
4227 // Reference initialization via an initializer list works thus:
4228 // If the initializer list consists of a single element that is
4229 // reference-related to the referenced type, bind directly to that element
4230 // (possibly creating temporaries).
4231 // Otherwise, initialize a temporary with the initializer list and
4232 // bind to that.
4233 if (InitList->getNumInits() == 1) {
4234 Expr *Initializer = InitList->getInit(0);
4235 QualType cv2T2 = Initializer->getType();
4236 Qualifiers T2Quals;
4237 QualType T2 = S.Context.getUnqualifiedArrayType(cv2T2, T2Quals);
4238
4239 // If this fails, creating a temporary wouldn't work either.
4240 if (ResolveOverloadedFunctionForReferenceBinding(S, Initializer, cv2T2, T2,
4241 T1, Sequence))
4242 return;
4243
4244 SourceLocation DeclLoc = Initializer->getBeginLoc();
4245 Sema::ReferenceCompareResult RefRelationship
4246 = S.CompareReferenceRelationship(DeclLoc, cv1T1, cv2T2);
4247 if (RefRelationship >= Sema::Ref_Related) {
4248 // Try to bind the reference here.
4249 TryReferenceInitializationCore(S, Entity, Kind, Initializer, cv1T1, T1,
4250 T1Quals, cv2T2, T2, T2Quals, Sequence);
4251 if (Sequence)
4252 Sequence.RewrapReferenceInitList(cv1T1, InitList);
4253 return;
4254 }
4255
4256 // Update the initializer if we've resolved an overloaded function.
4257 if (Sequence.step_begin() != Sequence.step_end())
4258 Sequence.RewrapReferenceInitList(cv1T1, InitList);
4259 }
4260
4261 // Not reference-related. Create a temporary and bind to that.
4262 InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(cv1T1);
4263
4264 TryListInitialization(S, TempEntity, Kind, InitList, Sequence,
4265 TreatUnavailableAsInvalid);
4266 if (Sequence) {
4267 if (DestType->isRValueReferenceType() ||
4268 (T1Quals.hasConst() && !T1Quals.hasVolatile()))
4269 Sequence.AddReferenceBindingStep(cv1T1, /*BindingTemporary=*/true);
4270 else
4271 Sequence.SetFailed(
4272 InitializationSequence::FK_NonConstLValueReferenceBindingToTemporary);
4273 }
4274 }
4275
4276 /// Attempt list initialization (C++0x [dcl.init.list])
TryListInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,InitListExpr * InitList,InitializationSequence & Sequence,bool TreatUnavailableAsInvalid)4277 static void TryListInitialization(Sema &S,
4278 const InitializedEntity &Entity,
4279 const InitializationKind &Kind,
4280 InitListExpr *InitList,
4281 InitializationSequence &Sequence,
4282 bool TreatUnavailableAsInvalid) {
4283 QualType DestType = Entity.getType();
4284
4285 // C++ doesn't allow scalar initialization with more than one argument.
4286 // But C99 complex numbers are scalars and it makes sense there.
4287 if (S.getLangOpts().CPlusPlus && DestType->isScalarType() &&
4288 !DestType->isAnyComplexType() && InitList->getNumInits() > 1) {
4289 Sequence.SetFailed(InitializationSequence::FK_TooManyInitsForScalar);
4290 return;
4291 }
4292 if (DestType->isReferenceType()) {
4293 TryReferenceListInitialization(S, Entity, Kind, InitList, Sequence,
4294 TreatUnavailableAsInvalid);
4295 return;
4296 }
4297
4298 if (DestType->isRecordType() &&
4299 !S.isCompleteType(InitList->getBeginLoc(), DestType)) {
4300 Sequence.setIncompleteTypeFailure(DestType);
4301 return;
4302 }
4303
4304 // C++11 [dcl.init.list]p3, per DR1467:
4305 // - If T is a class type and the initializer list has a single element of
4306 // type cv U, where U is T or a class derived from T, the object is
4307 // initialized from that element (by copy-initialization for
4308 // copy-list-initialization, or by direct-initialization for
4309 // direct-list-initialization).
4310 // - Otherwise, if T is a character array and the initializer list has a
4311 // single element that is an appropriately-typed string literal
4312 // (8.5.2 [dcl.init.string]), initialization is performed as described
4313 // in that section.
4314 // - Otherwise, if T is an aggregate, [...] (continue below).
4315 if (S.getLangOpts().CPlusPlus11 && InitList->getNumInits() == 1) {
4316 if (DestType->isRecordType()) {
4317 QualType InitType = InitList->getInit(0)->getType();
4318 if (S.Context.hasSameUnqualifiedType(InitType, DestType) ||
4319 S.IsDerivedFrom(InitList->getBeginLoc(), InitType, DestType)) {
4320 Expr *InitListAsExpr = InitList;
4321 TryConstructorInitialization(S, Entity, Kind, InitListAsExpr, DestType,
4322 DestType, Sequence,
4323 /*InitListSyntax*/false,
4324 /*IsInitListCopy*/true);
4325 return;
4326 }
4327 }
4328 if (const ArrayType *DestAT = S.Context.getAsArrayType(DestType)) {
4329 Expr *SubInit[1] = {InitList->getInit(0)};
4330 if (!isa<VariableArrayType>(DestAT) &&
4331 IsStringInit(SubInit[0], DestAT, S.Context) == SIF_None) {
4332 InitializationKind SubKind =
4333 Kind.getKind() == InitializationKind::IK_DirectList
4334 ? InitializationKind::CreateDirect(Kind.getLocation(),
4335 InitList->getLBraceLoc(),
4336 InitList->getRBraceLoc())
4337 : Kind;
4338 Sequence.InitializeFrom(S, Entity, SubKind, SubInit,
4339 /*TopLevelOfInitList*/ true,
4340 TreatUnavailableAsInvalid);
4341
4342 // TryStringLiteralInitialization() (in InitializeFrom()) will fail if
4343 // the element is not an appropriately-typed string literal, in which
4344 // case we should proceed as in C++11 (below).
4345 if (Sequence) {
4346 Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
4347 return;
4348 }
4349 }
4350 }
4351 }
4352
4353 // C++11 [dcl.init.list]p3:
4354 // - If T is an aggregate, aggregate initialization is performed.
4355 if ((DestType->isRecordType() && !DestType->isAggregateType()) ||
4356 (S.getLangOpts().CPlusPlus11 &&
4357 S.isStdInitializerList(DestType, nullptr))) {
4358 if (S.getLangOpts().CPlusPlus11) {
4359 // - Otherwise, if the initializer list has no elements and T is a
4360 // class type with a default constructor, the object is
4361 // value-initialized.
4362 if (InitList->getNumInits() == 0) {
4363 CXXRecordDecl *RD = DestType->getAsCXXRecordDecl();
4364 if (S.LookupDefaultConstructor(RD)) {
4365 TryValueInitialization(S, Entity, Kind, Sequence, InitList);
4366 return;
4367 }
4368 }
4369
4370 // - Otherwise, if T is a specialization of std::initializer_list<E>,
4371 // an initializer_list object constructed [...]
4372 if (TryInitializerListConstruction(S, InitList, DestType, Sequence,
4373 TreatUnavailableAsInvalid))
4374 return;
4375
4376 // - Otherwise, if T is a class type, constructors are considered.
4377 Expr *InitListAsExpr = InitList;
4378 TryConstructorInitialization(S, Entity, Kind, InitListAsExpr, DestType,
4379 DestType, Sequence, /*InitListSyntax*/true);
4380 } else
4381 Sequence.SetFailed(InitializationSequence::FK_InitListBadDestinationType);
4382 return;
4383 }
4384
4385 if (S.getLangOpts().CPlusPlus && !DestType->isAggregateType() &&
4386 InitList->getNumInits() == 1) {
4387 Expr *E = InitList->getInit(0);
4388
4389 // - Otherwise, if T is an enumeration with a fixed underlying type,
4390 // the initializer-list has a single element v, and the initialization
4391 // is direct-list-initialization, the object is initialized with the
4392 // value T(v); if a narrowing conversion is required to convert v to
4393 // the underlying type of T, the program is ill-formed.
4394 auto *ET = DestType->getAs<EnumType>();
4395 if (S.getLangOpts().CPlusPlus17 &&
4396 Kind.getKind() == InitializationKind::IK_DirectList &&
4397 ET && ET->getDecl()->isFixed() &&
4398 !S.Context.hasSameUnqualifiedType(E->getType(), DestType) &&
4399 (E->getType()->isIntegralOrEnumerationType() ||
4400 E->getType()->isFloatingType())) {
4401 // There are two ways that T(v) can work when T is an enumeration type.
4402 // If there is either an implicit conversion sequence from v to T or
4403 // a conversion function that can convert from v to T, then we use that.
4404 // Otherwise, if v is of integral, enumeration, or floating-point type,
4405 // it is converted to the enumeration type via its underlying type.
4406 // There is no overlap possible between these two cases (except when the
4407 // source value is already of the destination type), and the first
4408 // case is handled by the general case for single-element lists below.
4409 ImplicitConversionSequence ICS;
4410 ICS.setStandard();
4411 ICS.Standard.setAsIdentityConversion();
4412 if (!E->isRValue())
4413 ICS.Standard.First = ICK_Lvalue_To_Rvalue;
4414 // If E is of a floating-point type, then the conversion is ill-formed
4415 // due to narrowing, but go through the motions in order to produce the
4416 // right diagnostic.
4417 ICS.Standard.Second = E->getType()->isFloatingType()
4418 ? ICK_Floating_Integral
4419 : ICK_Integral_Conversion;
4420 ICS.Standard.setFromType(E->getType());
4421 ICS.Standard.setToType(0, E->getType());
4422 ICS.Standard.setToType(1, DestType);
4423 ICS.Standard.setToType(2, DestType);
4424 Sequence.AddConversionSequenceStep(ICS, ICS.Standard.getToType(2),
4425 /*TopLevelOfInitList*/true);
4426 Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
4427 return;
4428 }
4429
4430 // - Otherwise, if the initializer list has a single element of type E
4431 // [...references are handled above...], the object or reference is
4432 // initialized from that element (by copy-initialization for
4433 // copy-list-initialization, or by direct-initialization for
4434 // direct-list-initialization); if a narrowing conversion is required
4435 // to convert the element to T, the program is ill-formed.
4436 //
4437 // Per core-24034, this is direct-initialization if we were performing
4438 // direct-list-initialization and copy-initialization otherwise.
4439 // We can't use InitListChecker for this, because it always performs
4440 // copy-initialization. This only matters if we might use an 'explicit'
4441 // conversion operator, or for the special case conversion of nullptr_t to
4442 // bool, so we only need to handle those cases.
4443 //
4444 // FIXME: Why not do this in all cases?
4445 Expr *Init = InitList->getInit(0);
4446 if (Init->getType()->isRecordType() ||
4447 (Init->getType()->isNullPtrType() && DestType->isBooleanType())) {
4448 InitializationKind SubKind =
4449 Kind.getKind() == InitializationKind::IK_DirectList
4450 ? InitializationKind::CreateDirect(Kind.getLocation(),
4451 InitList->getLBraceLoc(),
4452 InitList->getRBraceLoc())
4453 : Kind;
4454 Expr *SubInit[1] = { Init };
4455 Sequence.InitializeFrom(S, Entity, SubKind, SubInit,
4456 /*TopLevelOfInitList*/true,
4457 TreatUnavailableAsInvalid);
4458 if (Sequence)
4459 Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
4460 return;
4461 }
4462 }
4463
4464 InitListChecker CheckInitList(S, Entity, InitList,
4465 DestType, /*VerifyOnly=*/true, TreatUnavailableAsInvalid);
4466 if (CheckInitList.HadError()) {
4467 Sequence.SetFailed(InitializationSequence::FK_ListInitializationFailed);
4468 return;
4469 }
4470
4471 // Add the list initialization step with the built init list.
4472 Sequence.AddListInitializationStep(DestType);
4473 }
4474
4475 /// Try a reference initialization that involves calling a conversion
4476 /// function.
TryRefInitWithConversionFunction(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,Expr * Initializer,bool AllowRValues,bool IsLValueRef,InitializationSequence & Sequence)4477 static OverloadingResult TryRefInitWithConversionFunction(
4478 Sema &S, const InitializedEntity &Entity, const InitializationKind &Kind,
4479 Expr *Initializer, bool AllowRValues, bool IsLValueRef,
4480 InitializationSequence &Sequence) {
4481 QualType DestType = Entity.getType();
4482 QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
4483 QualType T1 = cv1T1.getUnqualifiedType();
4484 QualType cv2T2 = Initializer->getType();
4485 QualType T2 = cv2T2.getUnqualifiedType();
4486
4487 assert(!S.CompareReferenceRelationship(Initializer->getBeginLoc(), T1, T2) &&
4488 "Must have incompatible references when binding via conversion");
4489
4490 // Build the candidate set directly in the initialization sequence
4491 // structure, so that it will persist if we fail.
4492 OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
4493 CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
4494
4495 // Determine whether we are allowed to call explicit conversion operators.
4496 // Note that none of [over.match.copy], [over.match.conv], nor
4497 // [over.match.ref] permit an explicit constructor to be chosen when
4498 // initializing a reference, not even for direct-initialization.
4499 bool AllowExplicitCtors = false;
4500 bool AllowExplicitConvs = Kind.allowExplicitConversionFunctionsInRefBinding();
4501
4502 const RecordType *T1RecordType = nullptr;
4503 if (AllowRValues && (T1RecordType = T1->getAs<RecordType>()) &&
4504 S.isCompleteType(Kind.getLocation(), T1)) {
4505 // The type we're converting to is a class type. Enumerate its constructors
4506 // to see if there is a suitable conversion.
4507 CXXRecordDecl *T1RecordDecl = cast<CXXRecordDecl>(T1RecordType->getDecl());
4508
4509 for (NamedDecl *D : S.LookupConstructors(T1RecordDecl)) {
4510 auto Info = getConstructorInfo(D);
4511 if (!Info.Constructor)
4512 continue;
4513
4514 if (!Info.Constructor->isInvalidDecl() &&
4515 Info.Constructor->isConvertingConstructor(/*AllowExplicit*/true)) {
4516 if (Info.ConstructorTmpl)
4517 S.AddTemplateOverloadCandidate(
4518 Info.ConstructorTmpl, Info.FoundDecl,
4519 /*ExplicitArgs*/ nullptr, Initializer, CandidateSet,
4520 /*SuppressUserConversions=*/true,
4521 /*PartialOverloading*/ false, AllowExplicitCtors);
4522 else
4523 S.AddOverloadCandidate(
4524 Info.Constructor, Info.FoundDecl, Initializer, CandidateSet,
4525 /*SuppressUserConversions=*/true,
4526 /*PartialOverloading*/ false, AllowExplicitCtors);
4527 }
4528 }
4529 }
4530 if (T1RecordType && T1RecordType->getDecl()->isInvalidDecl())
4531 return OR_No_Viable_Function;
4532
4533 const RecordType *T2RecordType = nullptr;
4534 if ((T2RecordType = T2->getAs<RecordType>()) &&
4535 S.isCompleteType(Kind.getLocation(), T2)) {
4536 // The type we're converting from is a class type, enumerate its conversion
4537 // functions.
4538 CXXRecordDecl *T2RecordDecl = cast<CXXRecordDecl>(T2RecordType->getDecl());
4539
4540 const auto &Conversions = T2RecordDecl->getVisibleConversionFunctions();
4541 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
4542 NamedDecl *D = *I;
4543 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
4544 if (isa<UsingShadowDecl>(D))
4545 D = cast<UsingShadowDecl>(D)->getTargetDecl();
4546
4547 FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
4548 CXXConversionDecl *Conv;
4549 if (ConvTemplate)
4550 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
4551 else
4552 Conv = cast<CXXConversionDecl>(D);
4553
4554 // If the conversion function doesn't return a reference type,
4555 // it can't be considered for this conversion unless we're allowed to
4556 // consider rvalues.
4557 // FIXME: Do we need to make sure that we only consider conversion
4558 // candidates with reference-compatible results? That might be needed to
4559 // break recursion.
4560 if ((AllowRValues ||
4561 Conv->getConversionType()->isLValueReferenceType())) {
4562 if (ConvTemplate)
4563 S.AddTemplateConversionCandidate(
4564 ConvTemplate, I.getPair(), ActingDC, Initializer, DestType,
4565 CandidateSet,
4566 /*AllowObjCConversionOnExplicit=*/false, AllowExplicitConvs);
4567 else
4568 S.AddConversionCandidate(
4569 Conv, I.getPair(), ActingDC, Initializer, DestType, CandidateSet,
4570 /*AllowObjCConversionOnExplicit=*/false, AllowExplicitConvs);
4571 }
4572 }
4573 }
4574 if (T2RecordType && T2RecordType->getDecl()->isInvalidDecl())
4575 return OR_No_Viable_Function;
4576
4577 SourceLocation DeclLoc = Initializer->getBeginLoc();
4578
4579 // Perform overload resolution. If it fails, return the failed result.
4580 OverloadCandidateSet::iterator Best;
4581 if (OverloadingResult Result
4582 = CandidateSet.BestViableFunction(S, DeclLoc, Best))
4583 return Result;
4584
4585 FunctionDecl *Function = Best->Function;
4586 // This is the overload that will be used for this initialization step if we
4587 // use this initialization. Mark it as referenced.
4588 Function->setReferenced();
4589
4590 // Compute the returned type and value kind of the conversion.
4591 QualType cv3T3;
4592 if (isa<CXXConversionDecl>(Function))
4593 cv3T3 = Function->getReturnType();
4594 else
4595 cv3T3 = T1;
4596
4597 ExprValueKind VK = VK_RValue;
4598 if (cv3T3->isLValueReferenceType())
4599 VK = VK_LValue;
4600 else if (const auto *RRef = cv3T3->getAs<RValueReferenceType>())
4601 VK = RRef->getPointeeType()->isFunctionType() ? VK_LValue : VK_XValue;
4602 cv3T3 = cv3T3.getNonLValueExprType(S.Context);
4603
4604 // Add the user-defined conversion step.
4605 bool HadMultipleCandidates = (CandidateSet.size() > 1);
4606 Sequence.AddUserConversionStep(Function, Best->FoundDecl, cv3T3,
4607 HadMultipleCandidates);
4608
4609 // Determine whether we'll need to perform derived-to-base adjustments or
4610 // other conversions.
4611 Sema::ReferenceConversions RefConv;
4612 Sema::ReferenceCompareResult NewRefRelationship =
4613 S.CompareReferenceRelationship(DeclLoc, T1, cv3T3, &RefConv);
4614
4615 // Add the final conversion sequence, if necessary.
4616 if (NewRefRelationship == Sema::Ref_Incompatible) {
4617 assert(!isa<CXXConstructorDecl>(Function) &&
4618 "should not have conversion after constructor");
4619
4620 ImplicitConversionSequence ICS;
4621 ICS.setStandard();
4622 ICS.Standard = Best->FinalConversion;
4623 Sequence.AddConversionSequenceStep(ICS, ICS.Standard.getToType(2));
4624
4625 // Every implicit conversion results in a prvalue, except for a glvalue
4626 // derived-to-base conversion, which we handle below.
4627 cv3T3 = ICS.Standard.getToType(2);
4628 VK = VK_RValue;
4629 }
4630
4631 // If the converted initializer is a prvalue, its type T4 is adjusted to
4632 // type "cv1 T4" and the temporary materialization conversion is applied.
4633 //
4634 // We adjust the cv-qualifications to match the reference regardless of
4635 // whether we have a prvalue so that the AST records the change. In this
4636 // case, T4 is "cv3 T3".
4637 QualType cv1T4 = S.Context.getQualifiedType(cv3T3, cv1T1.getQualifiers());
4638 if (cv1T4.getQualifiers() != cv3T3.getQualifiers())
4639 Sequence.AddQualificationConversionStep(cv1T4, VK);
4640 Sequence.AddReferenceBindingStep(cv1T4, VK == VK_RValue);
4641 VK = IsLValueRef ? VK_LValue : VK_XValue;
4642
4643 if (RefConv & Sema::ReferenceConversions::DerivedToBase)
4644 Sequence.AddDerivedToBaseCastStep(cv1T1, VK);
4645 else if (RefConv & Sema::ReferenceConversions::ObjC)
4646 Sequence.AddObjCObjectConversionStep(cv1T1);
4647 else if (RefConv & Sema::ReferenceConversions::Function)
4648 Sequence.AddQualificationConversionStep(cv1T1, VK);
4649 else if (RefConv & Sema::ReferenceConversions::Qualification) {
4650 if (!S.Context.hasSameType(cv1T4, cv1T1))
4651 Sequence.AddQualificationConversionStep(cv1T1, VK);
4652 }
4653
4654 return OR_Success;
4655 }
4656
4657 static void CheckCXX98CompatAccessibleCopy(Sema &S,
4658 const InitializedEntity &Entity,
4659 Expr *CurInitExpr);
4660
4661 /// Attempt reference initialization (C++0x [dcl.init.ref])
TryReferenceInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,Expr * Initializer,InitializationSequence & Sequence)4662 static void TryReferenceInitialization(Sema &S,
4663 const InitializedEntity &Entity,
4664 const InitializationKind &Kind,
4665 Expr *Initializer,
4666 InitializationSequence &Sequence) {
4667 QualType DestType = Entity.getType();
4668 QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
4669 Qualifiers T1Quals;
4670 QualType T1 = S.Context.getUnqualifiedArrayType(cv1T1, T1Quals);
4671 QualType cv2T2 = Initializer->getType();
4672 Qualifiers T2Quals;
4673 QualType T2 = S.Context.getUnqualifiedArrayType(cv2T2, T2Quals);
4674
4675 // If the initializer is the address of an overloaded function, try
4676 // to resolve the overloaded function. If all goes well, T2 is the
4677 // type of the resulting function.
4678 if (ResolveOverloadedFunctionForReferenceBinding(S, Initializer, cv2T2, T2,
4679 T1, Sequence))
4680 return;
4681
4682 // Delegate everything else to a subfunction.
4683 TryReferenceInitializationCore(S, Entity, Kind, Initializer, cv1T1, T1,
4684 T1Quals, cv2T2, T2, T2Quals, Sequence);
4685 }
4686
4687 /// Determine whether an expression is a non-referenceable glvalue (one to
4688 /// which a reference can never bind). Attempting to bind a reference to
4689 /// such a glvalue will always create a temporary.
isNonReferenceableGLValue(Expr * E)4690 static bool isNonReferenceableGLValue(Expr *E) {
4691 return E->refersToBitField() || E->refersToVectorElement() ||
4692 E->refersToMatrixElement();
4693 }
4694
4695 /// Reference initialization without resolving overloaded functions.
4696 ///
4697 /// We also can get here in C if we call a builtin which is declared as
4698 /// a function with a parameter of reference type (such as __builtin_va_end()).
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)4699 static void TryReferenceInitializationCore(Sema &S,
4700 const InitializedEntity &Entity,
4701 const InitializationKind &Kind,
4702 Expr *Initializer,
4703 QualType cv1T1, QualType T1,
4704 Qualifiers T1Quals,
4705 QualType cv2T2, QualType T2,
4706 Qualifiers T2Quals,
4707 InitializationSequence &Sequence) {
4708 QualType DestType = Entity.getType();
4709 SourceLocation DeclLoc = Initializer->getBeginLoc();
4710
4711 // Compute some basic properties of the types and the initializer.
4712 bool isLValueRef = DestType->isLValueReferenceType();
4713 bool isRValueRef = !isLValueRef;
4714 Expr::Classification InitCategory = Initializer->Classify(S.Context);
4715
4716 Sema::ReferenceConversions RefConv;
4717 Sema::ReferenceCompareResult RefRelationship =
4718 S.CompareReferenceRelationship(DeclLoc, cv1T1, cv2T2, &RefConv);
4719
4720 // C++0x [dcl.init.ref]p5:
4721 // A reference to type "cv1 T1" is initialized by an expression of type
4722 // "cv2 T2" as follows:
4723 //
4724 // - If the reference is an lvalue reference and the initializer
4725 // expression
4726 // Note the analogous bullet points for rvalue refs to functions. Because
4727 // there are no function rvalues in C++, rvalue refs to functions are treated
4728 // like lvalue refs.
4729 OverloadingResult ConvOvlResult = OR_Success;
4730 bool T1Function = T1->isFunctionType();
4731 if (isLValueRef || T1Function) {
4732 if (InitCategory.isLValue() && !isNonReferenceableGLValue(Initializer) &&
4733 (RefRelationship == Sema::Ref_Compatible ||
4734 (Kind.isCStyleOrFunctionalCast() &&
4735 RefRelationship == Sema::Ref_Related))) {
4736 // - is an lvalue (but is not a bit-field), and "cv1 T1" is
4737 // reference-compatible with "cv2 T2," or
4738 if (RefConv & (Sema::ReferenceConversions::DerivedToBase |
4739 Sema::ReferenceConversions::ObjC)) {
4740 // If we're converting the pointee, add any qualifiers first;
4741 // these qualifiers must all be top-level, so just convert to "cv1 T2".
4742 if (RefConv & (Sema::ReferenceConversions::Qualification))
4743 Sequence.AddQualificationConversionStep(
4744 S.Context.getQualifiedType(T2, T1Quals),
4745 Initializer->getValueKind());
4746 if (RefConv & Sema::ReferenceConversions::DerivedToBase)
4747 Sequence.AddDerivedToBaseCastStep(cv1T1, VK_LValue);
4748 else
4749 Sequence.AddObjCObjectConversionStep(cv1T1);
4750 } else if (RefConv & (Sema::ReferenceConversions::Qualification |
4751 Sema::ReferenceConversions::Function)) {
4752 // Perform a (possibly multi-level) qualification conversion.
4753 // FIXME: Should we use a different step kind for function conversions?
4754 Sequence.AddQualificationConversionStep(cv1T1,
4755 Initializer->getValueKind());
4756 }
4757
4758 // We only create a temporary here when binding a reference to a
4759 // bit-field or vector element. Those cases are't supposed to be
4760 // handled by this bullet, but the outcome is the same either way.
4761 Sequence.AddReferenceBindingStep(cv1T1, false);
4762 return;
4763 }
4764
4765 // - has a class type (i.e., T2 is a class type), where T1 is not
4766 // reference-related to T2, and can be implicitly converted to an
4767 // lvalue of type "cv3 T3," where "cv1 T1" is reference-compatible
4768 // with "cv3 T3" (this conversion is selected by enumerating the
4769 // applicable conversion functions (13.3.1.6) and choosing the best
4770 // one through overload resolution (13.3)),
4771 // If we have an rvalue ref to function type here, the rhs must be
4772 // an rvalue. DR1287 removed the "implicitly" here.
4773 if (RefRelationship == Sema::Ref_Incompatible && T2->isRecordType() &&
4774 (isLValueRef || InitCategory.isRValue())) {
4775 if (S.getLangOpts().CPlusPlus) {
4776 // Try conversion functions only for C++.
4777 ConvOvlResult = TryRefInitWithConversionFunction(
4778 S, Entity, Kind, Initializer, /*AllowRValues*/ isRValueRef,
4779 /*IsLValueRef*/ isLValueRef, Sequence);
4780 if (ConvOvlResult == OR_Success)
4781 return;
4782 if (ConvOvlResult != OR_No_Viable_Function)
4783 Sequence.SetOverloadFailure(
4784 InitializationSequence::FK_ReferenceInitOverloadFailed,
4785 ConvOvlResult);
4786 } else {
4787 ConvOvlResult = OR_No_Viable_Function;
4788 }
4789 }
4790 }
4791
4792 // - Otherwise, the reference shall be an lvalue reference to a
4793 // non-volatile const type (i.e., cv1 shall be const), or the reference
4794 // shall be an rvalue reference.
4795 // For address spaces, we interpret this to mean that an addr space
4796 // of a reference "cv1 T1" is a superset of addr space of "cv2 T2".
4797 if (isLValueRef && !(T1Quals.hasConst() && !T1Quals.hasVolatile() &&
4798 T1Quals.isAddressSpaceSupersetOf(T2Quals))) {
4799 if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy)
4800 Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
4801 else if (ConvOvlResult && !Sequence.getFailedCandidateSet().empty())
4802 Sequence.SetOverloadFailure(
4803 InitializationSequence::FK_ReferenceInitOverloadFailed,
4804 ConvOvlResult);
4805 else if (!InitCategory.isLValue())
4806 Sequence.SetFailed(
4807 T1Quals.isAddressSpaceSupersetOf(T2Quals)
4808 ? InitializationSequence::
4809 FK_NonConstLValueReferenceBindingToTemporary
4810 : InitializationSequence::FK_ReferenceInitDropsQualifiers);
4811 else {
4812 InitializationSequence::FailureKind FK;
4813 switch (RefRelationship) {
4814 case Sema::Ref_Compatible:
4815 if (Initializer->refersToBitField())
4816 FK = InitializationSequence::
4817 FK_NonConstLValueReferenceBindingToBitfield;
4818 else if (Initializer->refersToVectorElement())
4819 FK = InitializationSequence::
4820 FK_NonConstLValueReferenceBindingToVectorElement;
4821 else if (Initializer->refersToMatrixElement())
4822 FK = InitializationSequence::
4823 FK_NonConstLValueReferenceBindingToMatrixElement;
4824 else
4825 llvm_unreachable("unexpected kind of compatible initializer");
4826 break;
4827 case Sema::Ref_Related:
4828 FK = InitializationSequence::FK_ReferenceInitDropsQualifiers;
4829 break;
4830 case Sema::Ref_Incompatible:
4831 FK = InitializationSequence::
4832 FK_NonConstLValueReferenceBindingToUnrelated;
4833 break;
4834 }
4835 Sequence.SetFailed(FK);
4836 }
4837 return;
4838 }
4839
4840 // - If the initializer expression
4841 // - is an
4842 // [<=14] xvalue (but not a bit-field), class prvalue, array prvalue, or
4843 // [1z] rvalue (but not a bit-field) or
4844 // function lvalue and "cv1 T1" is reference-compatible with "cv2 T2"
4845 //
4846 // Note: functions are handled above and below rather than here...
4847 if (!T1Function &&
4848 (RefRelationship == Sema::Ref_Compatible ||
4849 (Kind.isCStyleOrFunctionalCast() &&
4850 RefRelationship == Sema::Ref_Related)) &&
4851 ((InitCategory.isXValue() && !isNonReferenceableGLValue(Initializer)) ||
4852 (InitCategory.isPRValue() &&
4853 (S.getLangOpts().CPlusPlus17 || T2->isRecordType() ||
4854 T2->isArrayType())))) {
4855 ExprValueKind ValueKind = InitCategory.isXValue() ? VK_XValue : VK_RValue;
4856 if (InitCategory.isPRValue() && T2->isRecordType()) {
4857 // The corresponding bullet in C++03 [dcl.init.ref]p5 gives the
4858 // compiler the freedom to perform a copy here or bind to the
4859 // object, while C++0x requires that we bind directly to the
4860 // object. Hence, we always bind to the object without making an
4861 // extra copy. However, in C++03 requires that we check for the
4862 // presence of a suitable copy constructor:
4863 //
4864 // The constructor that would be used to make the copy shall
4865 // be callable whether or not the copy is actually done.
4866 if (!S.getLangOpts().CPlusPlus11 && !S.getLangOpts().MicrosoftExt)
4867 Sequence.AddExtraneousCopyToTemporary(cv2T2);
4868 else if (S.getLangOpts().CPlusPlus11)
4869 CheckCXX98CompatAccessibleCopy(S, Entity, Initializer);
4870 }
4871
4872 // C++1z [dcl.init.ref]/5.2.1.2:
4873 // If the converted initializer is a prvalue, its type T4 is adjusted
4874 // to type "cv1 T4" and the temporary materialization conversion is
4875 // applied.
4876 // Postpone address space conversions to after the temporary materialization
4877 // conversion to allow creating temporaries in the alloca address space.
4878 auto T1QualsIgnoreAS = T1Quals;
4879 auto T2QualsIgnoreAS = T2Quals;
4880 if (T1Quals.getAddressSpace() != T2Quals.getAddressSpace()) {
4881 T1QualsIgnoreAS.removeAddressSpace();
4882 T2QualsIgnoreAS.removeAddressSpace();
4883 }
4884 QualType cv1T4 = S.Context.getQualifiedType(cv2T2, T1QualsIgnoreAS);
4885 if (T1QualsIgnoreAS != T2QualsIgnoreAS)
4886 Sequence.AddQualificationConversionStep(cv1T4, ValueKind);
4887 Sequence.AddReferenceBindingStep(cv1T4, ValueKind == VK_RValue);
4888 ValueKind = isLValueRef ? VK_LValue : VK_XValue;
4889 // Add addr space conversion if required.
4890 if (T1Quals.getAddressSpace() != T2Quals.getAddressSpace()) {
4891 auto T4Quals = cv1T4.getQualifiers();
4892 T4Quals.addAddressSpace(T1Quals.getAddressSpace());
4893 QualType cv1T4WithAS = S.Context.getQualifiedType(T2, T4Quals);
4894 Sequence.AddQualificationConversionStep(cv1T4WithAS, ValueKind);
4895 cv1T4 = cv1T4WithAS;
4896 }
4897
4898 // In any case, the reference is bound to the resulting glvalue (or to
4899 // an appropriate base class subobject).
4900 if (RefConv & Sema::ReferenceConversions::DerivedToBase)
4901 Sequence.AddDerivedToBaseCastStep(cv1T1, ValueKind);
4902 else if (RefConv & Sema::ReferenceConversions::ObjC)
4903 Sequence.AddObjCObjectConversionStep(cv1T1);
4904 else if (RefConv & Sema::ReferenceConversions::Qualification) {
4905 if (!S.Context.hasSameType(cv1T4, cv1T1))
4906 Sequence.AddQualificationConversionStep(cv1T1, ValueKind);
4907 }
4908 return;
4909 }
4910
4911 // - has a class type (i.e., T2 is a class type), where T1 is not
4912 // reference-related to T2, and can be implicitly converted to an
4913 // xvalue, class prvalue, or function lvalue of type "cv3 T3",
4914 // where "cv1 T1" is reference-compatible with "cv3 T3",
4915 //
4916 // DR1287 removes the "implicitly" here.
4917 if (T2->isRecordType()) {
4918 if (RefRelationship == Sema::Ref_Incompatible) {
4919 ConvOvlResult = TryRefInitWithConversionFunction(
4920 S, Entity, Kind, Initializer, /*AllowRValues*/ true,
4921 /*IsLValueRef*/ isLValueRef, Sequence);
4922 if (ConvOvlResult)
4923 Sequence.SetOverloadFailure(
4924 InitializationSequence::FK_ReferenceInitOverloadFailed,
4925 ConvOvlResult);
4926
4927 return;
4928 }
4929
4930 if (RefRelationship == Sema::Ref_Compatible &&
4931 isRValueRef && InitCategory.isLValue()) {
4932 Sequence.SetFailed(
4933 InitializationSequence::FK_RValueReferenceBindingToLValue);
4934 return;
4935 }
4936
4937 Sequence.SetFailed(InitializationSequence::FK_ReferenceInitDropsQualifiers);
4938 return;
4939 }
4940
4941 // - Otherwise, a temporary of type "cv1 T1" is created and initialized
4942 // from the initializer expression using the rules for a non-reference
4943 // copy-initialization (8.5). The reference is then bound to the
4944 // temporary. [...]
4945
4946 // Ignore address space of reference type at this point and perform address
4947 // space conversion after the reference binding step.
4948 QualType cv1T1IgnoreAS =
4949 T1Quals.hasAddressSpace()
4950 ? S.Context.getQualifiedType(T1, T1Quals.withoutAddressSpace())
4951 : cv1T1;
4952
4953 InitializedEntity TempEntity =
4954 InitializedEntity::InitializeTemporary(cv1T1IgnoreAS);
4955
4956 // FIXME: Why do we use an implicit conversion here rather than trying
4957 // copy-initialization?
4958 ImplicitConversionSequence ICS
4959 = S.TryImplicitConversion(Initializer, TempEntity.getType(),
4960 /*SuppressUserConversions=*/false,
4961 Sema::AllowedExplicit::None,
4962 /*FIXME:InOverloadResolution=*/false,
4963 /*CStyle=*/Kind.isCStyleOrFunctionalCast(),
4964 /*AllowObjCWritebackConversion=*/false);
4965
4966 if (ICS.isBad()) {
4967 // FIXME: Use the conversion function set stored in ICS to turn
4968 // this into an overloading ambiguity diagnostic. However, we need
4969 // to keep that set as an OverloadCandidateSet rather than as some
4970 // other kind of set.
4971 if (ConvOvlResult && !Sequence.getFailedCandidateSet().empty())
4972 Sequence.SetOverloadFailure(
4973 InitializationSequence::FK_ReferenceInitOverloadFailed,
4974 ConvOvlResult);
4975 else if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy)
4976 Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
4977 else
4978 Sequence.SetFailed(InitializationSequence::FK_ReferenceInitFailed);
4979 return;
4980 } else {
4981 Sequence.AddConversionSequenceStep(ICS, TempEntity.getType());
4982 }
4983
4984 // [...] If T1 is reference-related to T2, cv1 must be the
4985 // same cv-qualification as, or greater cv-qualification
4986 // than, cv2; otherwise, the program is ill-formed.
4987 unsigned T1CVRQuals = T1Quals.getCVRQualifiers();
4988 unsigned T2CVRQuals = T2Quals.getCVRQualifiers();
4989 if ((RefRelationship == Sema::Ref_Related &&
4990 (T1CVRQuals | T2CVRQuals) != T1CVRQuals) ||
4991 !T1Quals.isAddressSpaceSupersetOf(T2Quals)) {
4992 Sequence.SetFailed(InitializationSequence::FK_ReferenceInitDropsQualifiers);
4993 return;
4994 }
4995
4996 // [...] If T1 is reference-related to T2 and the reference is an rvalue
4997 // reference, the initializer expression shall not be an lvalue.
4998 if (RefRelationship >= Sema::Ref_Related && !isLValueRef &&
4999 InitCategory.isLValue()) {
5000 Sequence.SetFailed(
5001 InitializationSequence::FK_RValueReferenceBindingToLValue);
5002 return;
5003 }
5004
5005 Sequence.AddReferenceBindingStep(cv1T1IgnoreAS, /*BindingTemporary=*/true);
5006
5007 if (T1Quals.hasAddressSpace()) {
5008 if (!Qualifiers::isAddressSpaceSupersetOf(T1Quals.getAddressSpace(),
5009 LangAS::Default)) {
5010 Sequence.SetFailed(
5011 InitializationSequence::FK_ReferenceAddrspaceMismatchTemporary);
5012 return;
5013 }
5014 Sequence.AddQualificationConversionStep(cv1T1, isLValueRef ? VK_LValue
5015 : VK_XValue);
5016 }
5017 }
5018
5019 /// Attempt character array initialization from a string literal
5020 /// (C++ [dcl.init.string], C99 6.7.8).
TryStringLiteralInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,Expr * Initializer,InitializationSequence & Sequence)5021 static void TryStringLiteralInitialization(Sema &S,
5022 const InitializedEntity &Entity,
5023 const InitializationKind &Kind,
5024 Expr *Initializer,
5025 InitializationSequence &Sequence) {
5026 Sequence.AddStringInitStep(Entity.getType());
5027 }
5028
5029 /// Attempt value initialization (C++ [dcl.init]p7).
TryValueInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,InitializationSequence & Sequence,InitListExpr * InitList)5030 static void TryValueInitialization(Sema &S,
5031 const InitializedEntity &Entity,
5032 const InitializationKind &Kind,
5033 InitializationSequence &Sequence,
5034 InitListExpr *InitList) {
5035 assert((!InitList || InitList->getNumInits() == 0) &&
5036 "Shouldn't use value-init for non-empty init lists");
5037
5038 // C++98 [dcl.init]p5, C++11 [dcl.init]p7:
5039 //
5040 // To value-initialize an object of type T means:
5041 QualType T = Entity.getType();
5042
5043 // -- if T is an array type, then each element is value-initialized;
5044 T = S.Context.getBaseElementType(T);
5045
5046 if (const RecordType *RT = T->getAs<RecordType>()) {
5047 if (CXXRecordDecl *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
5048 bool NeedZeroInitialization = true;
5049 // C++98:
5050 // -- if T is a class type (clause 9) with a user-declared constructor
5051 // (12.1), then the default constructor for T is called (and the
5052 // initialization is ill-formed if T has no accessible default
5053 // constructor);
5054 // C++11:
5055 // -- if T is a class type (clause 9) with either no default constructor
5056 // (12.1 [class.ctor]) or a default constructor that is user-provided
5057 // or deleted, then the object is default-initialized;
5058 //
5059 // Note that the C++11 rule is the same as the C++98 rule if there are no
5060 // defaulted or deleted constructors, so we just use it unconditionally.
5061 CXXConstructorDecl *CD = S.LookupDefaultConstructor(ClassDecl);
5062 if (!CD || !CD->getCanonicalDecl()->isDefaulted() || CD->isDeleted())
5063 NeedZeroInitialization = false;
5064
5065 // -- if T is a (possibly cv-qualified) non-union class type without a
5066 // user-provided or deleted default constructor, then the object is
5067 // zero-initialized and, if T has a non-trivial default constructor,
5068 // default-initialized;
5069 // The 'non-union' here was removed by DR1502. The 'non-trivial default
5070 // constructor' part was removed by DR1507.
5071 if (NeedZeroInitialization)
5072 Sequence.AddZeroInitializationStep(Entity.getType());
5073
5074 // C++03:
5075 // -- if T is a non-union class type without a user-declared constructor,
5076 // then every non-static data member and base class component of T is
5077 // value-initialized;
5078 // [...] A program that calls for [...] value-initialization of an
5079 // entity of reference type is ill-formed.
5080 //
5081 // C++11 doesn't need this handling, because value-initialization does not
5082 // occur recursively there, and the implicit default constructor is
5083 // defined as deleted in the problematic cases.
5084 if (!S.getLangOpts().CPlusPlus11 &&
5085 ClassDecl->hasUninitializedReferenceMember()) {
5086 Sequence.SetFailed(InitializationSequence::FK_TooManyInitsForReference);
5087 return;
5088 }
5089
5090 // If this is list-value-initialization, pass the empty init list on when
5091 // building the constructor call. This affects the semantics of a few
5092 // things (such as whether an explicit default constructor can be called).
5093 Expr *InitListAsExpr = InitList;
5094 MultiExprArg Args(&InitListAsExpr, InitList ? 1 : 0);
5095 bool InitListSyntax = InitList;
5096
5097 // FIXME: Instead of creating a CXXConstructExpr of array type here,
5098 // wrap a class-typed CXXConstructExpr in an ArrayInitLoopExpr.
5099 return TryConstructorInitialization(
5100 S, Entity, Kind, Args, T, Entity.getType(), Sequence, InitListSyntax);
5101 }
5102 }
5103
5104 Sequence.AddZeroInitializationStep(Entity.getType());
5105 }
5106
5107 /// Attempt default initialization (C++ [dcl.init]p6).
TryDefaultInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,InitializationSequence & Sequence)5108 static void TryDefaultInitialization(Sema &S,
5109 const InitializedEntity &Entity,
5110 const InitializationKind &Kind,
5111 InitializationSequence &Sequence) {
5112 assert(Kind.getKind() == InitializationKind::IK_Default);
5113
5114 // C++ [dcl.init]p6:
5115 // To default-initialize an object of type T means:
5116 // - if T is an array type, each element is default-initialized;
5117 QualType DestType = S.Context.getBaseElementType(Entity.getType());
5118
5119 // - if T is a (possibly cv-qualified) class type (Clause 9), the default
5120 // constructor for T is called (and the initialization is ill-formed if
5121 // T has no accessible default constructor);
5122 if (DestType->isRecordType() && S.getLangOpts().CPlusPlus) {
5123 TryConstructorInitialization(S, Entity, Kind, None, DestType,
5124 Entity.getType(), Sequence);
5125 return;
5126 }
5127
5128 // - otherwise, no initialization is performed.
5129
5130 // If a program calls for the default initialization of an object of
5131 // a const-qualified type T, T shall be a class type with a user-provided
5132 // default constructor.
5133 if (DestType.isConstQualified() && S.getLangOpts().CPlusPlus) {
5134 if (!maybeRecoverWithZeroInitialization(S, Sequence, Entity))
5135 Sequence.SetFailed(InitializationSequence::FK_DefaultInitOfConst);
5136 return;
5137 }
5138
5139 // If the destination type has a lifetime property, zero-initialize it.
5140 if (DestType.getQualifiers().hasObjCLifetime()) {
5141 Sequence.AddZeroInitializationStep(Entity.getType());
5142 return;
5143 }
5144 }
5145
5146 /// Attempt a user-defined conversion between two types (C++ [dcl.init]),
5147 /// which enumerates all conversion functions and performs overload resolution
5148 /// to select the best.
TryUserDefinedConversion(Sema & S,QualType DestType,const InitializationKind & Kind,Expr * Initializer,InitializationSequence & Sequence,bool TopLevelOfInitList)5149 static void TryUserDefinedConversion(Sema &S,
5150 QualType DestType,
5151 const InitializationKind &Kind,
5152 Expr *Initializer,
5153 InitializationSequence &Sequence,
5154 bool TopLevelOfInitList) {
5155 assert(!DestType->isReferenceType() && "References are handled elsewhere");
5156 QualType SourceType = Initializer->getType();
5157 assert((DestType->isRecordType() || SourceType->isRecordType()) &&
5158 "Must have a class type to perform a user-defined conversion");
5159
5160 // Build the candidate set directly in the initialization sequence
5161 // structure, so that it will persist if we fail.
5162 OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
5163 CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
5164 CandidateSet.setDestAS(DestType.getQualifiers().getAddressSpace());
5165
5166 // Determine whether we are allowed to call explicit constructors or
5167 // explicit conversion operators.
5168 bool AllowExplicit = Kind.AllowExplicit();
5169
5170 if (const RecordType *DestRecordType = DestType->getAs<RecordType>()) {
5171 // The type we're converting to is a class type. Enumerate its constructors
5172 // to see if there is a suitable conversion.
5173 CXXRecordDecl *DestRecordDecl
5174 = cast<CXXRecordDecl>(DestRecordType->getDecl());
5175
5176 // Try to complete the type we're converting to.
5177 if (S.isCompleteType(Kind.getLocation(), DestType)) {
5178 for (NamedDecl *D : S.LookupConstructors(DestRecordDecl)) {
5179 auto Info = getConstructorInfo(D);
5180 if (!Info.Constructor)
5181 continue;
5182
5183 if (!Info.Constructor->isInvalidDecl() &&
5184 Info.Constructor->isConvertingConstructor(/*AllowExplicit*/true)) {
5185 if (Info.ConstructorTmpl)
5186 S.AddTemplateOverloadCandidate(
5187 Info.ConstructorTmpl, Info.FoundDecl,
5188 /*ExplicitArgs*/ nullptr, Initializer, CandidateSet,
5189 /*SuppressUserConversions=*/true,
5190 /*PartialOverloading*/ false, AllowExplicit);
5191 else
5192 S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl,
5193 Initializer, CandidateSet,
5194 /*SuppressUserConversions=*/true,
5195 /*PartialOverloading*/ false, AllowExplicit);
5196 }
5197 }
5198 }
5199 }
5200
5201 SourceLocation DeclLoc = Initializer->getBeginLoc();
5202
5203 if (const RecordType *SourceRecordType = SourceType->getAs<RecordType>()) {
5204 // The type we're converting from is a class type, enumerate its conversion
5205 // functions.
5206
5207 // We can only enumerate the conversion functions for a complete type; if
5208 // the type isn't complete, simply skip this step.
5209 if (S.isCompleteType(DeclLoc, SourceType)) {
5210 CXXRecordDecl *SourceRecordDecl
5211 = cast<CXXRecordDecl>(SourceRecordType->getDecl());
5212
5213 const auto &Conversions =
5214 SourceRecordDecl->getVisibleConversionFunctions();
5215 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
5216 NamedDecl *D = *I;
5217 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
5218 if (isa<UsingShadowDecl>(D))
5219 D = cast<UsingShadowDecl>(D)->getTargetDecl();
5220
5221 FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
5222 CXXConversionDecl *Conv;
5223 if (ConvTemplate)
5224 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
5225 else
5226 Conv = cast<CXXConversionDecl>(D);
5227
5228 if (ConvTemplate)
5229 S.AddTemplateConversionCandidate(
5230 ConvTemplate, I.getPair(), ActingDC, Initializer, DestType,
5231 CandidateSet, AllowExplicit, AllowExplicit);
5232 else
5233 S.AddConversionCandidate(Conv, I.getPair(), ActingDC, Initializer,
5234 DestType, CandidateSet, AllowExplicit,
5235 AllowExplicit);
5236 }
5237 }
5238 }
5239
5240 // Perform overload resolution. If it fails, return the failed result.
5241 OverloadCandidateSet::iterator Best;
5242 if (OverloadingResult Result
5243 = CandidateSet.BestViableFunction(S, DeclLoc, Best)) {
5244 Sequence.SetOverloadFailure(
5245 InitializationSequence::FK_UserConversionOverloadFailed,
5246 Result);
5247 return;
5248 }
5249
5250 FunctionDecl *Function = Best->Function;
5251 Function->setReferenced();
5252 bool HadMultipleCandidates = (CandidateSet.size() > 1);
5253
5254 if (isa<CXXConstructorDecl>(Function)) {
5255 // Add the user-defined conversion step. Any cv-qualification conversion is
5256 // subsumed by the initialization. Per DR5, the created temporary is of the
5257 // cv-unqualified type of the destination.
5258 Sequence.AddUserConversionStep(Function, Best->FoundDecl,
5259 DestType.getUnqualifiedType(),
5260 HadMultipleCandidates);
5261
5262 // C++14 and before:
5263 // - if the function is a constructor, the call initializes a temporary
5264 // of the cv-unqualified version of the destination type. The [...]
5265 // temporary [...] is then used to direct-initialize, according to the
5266 // rules above, the object that is the destination of the
5267 // copy-initialization.
5268 // Note that this just performs a simple object copy from the temporary.
5269 //
5270 // C++17:
5271 // - if the function is a constructor, the call is a prvalue of the
5272 // cv-unqualified version of the destination type whose return object
5273 // is initialized by the constructor. The call is used to
5274 // direct-initialize, according to the rules above, the object that
5275 // is the destination of the copy-initialization.
5276 // Therefore we need to do nothing further.
5277 //
5278 // FIXME: Mark this copy as extraneous.
5279 if (!S.getLangOpts().CPlusPlus17)
5280 Sequence.AddFinalCopy(DestType);
5281 else if (DestType.hasQualifiers())
5282 Sequence.AddQualificationConversionStep(DestType, VK_RValue);
5283 return;
5284 }
5285
5286 // Add the user-defined conversion step that calls the conversion function.
5287 QualType ConvType = Function->getCallResultType();
5288 Sequence.AddUserConversionStep(Function, Best->FoundDecl, ConvType,
5289 HadMultipleCandidates);
5290
5291 if (ConvType->getAs<RecordType>()) {
5292 // The call is used to direct-initialize [...] the object that is the
5293 // destination of the copy-initialization.
5294 //
5295 // In C++17, this does not call a constructor if we enter /17.6.1:
5296 // - If the initializer expression is a prvalue and the cv-unqualified
5297 // version of the source type is the same as the class of the
5298 // destination [... do not make an extra copy]
5299 //
5300 // FIXME: Mark this copy as extraneous.
5301 if (!S.getLangOpts().CPlusPlus17 ||
5302 Function->getReturnType()->isReferenceType() ||
5303 !S.Context.hasSameUnqualifiedType(ConvType, DestType))
5304 Sequence.AddFinalCopy(DestType);
5305 else if (!S.Context.hasSameType(ConvType, DestType))
5306 Sequence.AddQualificationConversionStep(DestType, VK_RValue);
5307 return;
5308 }
5309
5310 // If the conversion following the call to the conversion function
5311 // is interesting, add it as a separate step.
5312 if (Best->FinalConversion.First || Best->FinalConversion.Second ||
5313 Best->FinalConversion.Third) {
5314 ImplicitConversionSequence ICS;
5315 ICS.setStandard();
5316 ICS.Standard = Best->FinalConversion;
5317 Sequence.AddConversionSequenceStep(ICS, DestType, TopLevelOfInitList);
5318 }
5319 }
5320
5321 /// An egregious hack for compatibility with libstdc++-4.2: in <tr1/hashtable>,
5322 /// a function with a pointer return type contains a 'return false;' statement.
5323 /// In C++11, 'false' is not a null pointer, so this breaks the build of any
5324 /// code using that header.
5325 ///
5326 /// Work around this by treating 'return false;' as zero-initializing the result
5327 /// if it's used in a pointer-returning function in a system header.
isLibstdcxxPointerReturnFalseHack(Sema & S,const InitializedEntity & Entity,const Expr * Init)5328 static bool isLibstdcxxPointerReturnFalseHack(Sema &S,
5329 const InitializedEntity &Entity,
5330 const Expr *Init) {
5331 return S.getLangOpts().CPlusPlus11 &&
5332 Entity.getKind() == InitializedEntity::EK_Result &&
5333 Entity.getType()->isPointerType() &&
5334 isa<CXXBoolLiteralExpr>(Init) &&
5335 !cast<CXXBoolLiteralExpr>(Init)->getValue() &&
5336 S.getSourceManager().isInSystemHeader(Init->getExprLoc());
5337 }
5338
5339 /// The non-zero enum values here are indexes into diagnostic alternatives.
5340 enum InvalidICRKind { IIK_okay, IIK_nonlocal, IIK_nonscalar };
5341
5342 /// Determines whether this expression is an acceptable ICR source.
isInvalidICRSource(ASTContext & C,Expr * e,bool isAddressOf,bool & isWeakAccess)5343 static InvalidICRKind isInvalidICRSource(ASTContext &C, Expr *e,
5344 bool isAddressOf, bool &isWeakAccess) {
5345 // Skip parens.
5346 e = e->IgnoreParens();
5347
5348 // Skip address-of nodes.
5349 if (UnaryOperator *op = dyn_cast<UnaryOperator>(e)) {
5350 if (op->getOpcode() == UO_AddrOf)
5351 return isInvalidICRSource(C, op->getSubExpr(), /*addressof*/ true,
5352 isWeakAccess);
5353
5354 // Skip certain casts.
5355 } else if (CastExpr *ce = dyn_cast<CastExpr>(e)) {
5356 switch (ce->getCastKind()) {
5357 case CK_Dependent:
5358 case CK_BitCast:
5359 case CK_LValueBitCast:
5360 case CK_NoOp:
5361 return isInvalidICRSource(C, ce->getSubExpr(), isAddressOf, isWeakAccess);
5362
5363 case CK_ArrayToPointerDecay:
5364 return IIK_nonscalar;
5365
5366 case CK_NullToPointer:
5367 return IIK_okay;
5368
5369 default:
5370 break;
5371 }
5372
5373 // If we have a declaration reference, it had better be a local variable.
5374 } else if (isa<DeclRefExpr>(e)) {
5375 // set isWeakAccess to true, to mean that there will be an implicit
5376 // load which requires a cleanup.
5377 if (e->getType().getObjCLifetime() == Qualifiers::OCL_Weak)
5378 isWeakAccess = true;
5379
5380 if (!isAddressOf) return IIK_nonlocal;
5381
5382 VarDecl *var = dyn_cast<VarDecl>(cast<DeclRefExpr>(e)->getDecl());
5383 if (!var) return IIK_nonlocal;
5384
5385 return (var->hasLocalStorage() ? IIK_okay : IIK_nonlocal);
5386
5387 // If we have a conditional operator, check both sides.
5388 } else if (ConditionalOperator *cond = dyn_cast<ConditionalOperator>(e)) {
5389 if (InvalidICRKind iik = isInvalidICRSource(C, cond->getLHS(), isAddressOf,
5390 isWeakAccess))
5391 return iik;
5392
5393 return isInvalidICRSource(C, cond->getRHS(), isAddressOf, isWeakAccess);
5394
5395 // These are never scalar.
5396 } else if (isa<ArraySubscriptExpr>(e)) {
5397 return IIK_nonscalar;
5398
5399 // Otherwise, it needs to be a null pointer constant.
5400 } else {
5401 return (e->isNullPointerConstant(C, Expr::NPC_ValueDependentIsNull)
5402 ? IIK_okay : IIK_nonlocal);
5403 }
5404
5405 return IIK_nonlocal;
5406 }
5407
5408 /// Check whether the given expression is a valid operand for an
5409 /// indirect copy/restore.
checkIndirectCopyRestoreSource(Sema & S,Expr * src)5410 static void checkIndirectCopyRestoreSource(Sema &S, Expr *src) {
5411 assert(src->isRValue());
5412 bool isWeakAccess = false;
5413 InvalidICRKind iik = isInvalidICRSource(S.Context, src, false, isWeakAccess);
5414 // If isWeakAccess to true, there will be an implicit
5415 // load which requires a cleanup.
5416 if (S.getLangOpts().ObjCAutoRefCount && isWeakAccess)
5417 S.Cleanup.setExprNeedsCleanups(true);
5418
5419 if (iik == IIK_okay) return;
5420
5421 S.Diag(src->getExprLoc(), diag::err_arc_nonlocal_writeback)
5422 << ((unsigned) iik - 1) // shift index into diagnostic explanations
5423 << src->getSourceRange();
5424 }
5425
5426 /// Determine whether we have compatible array types for the
5427 /// purposes of GNU by-copy array initialization.
hasCompatibleArrayTypes(ASTContext & Context,const ArrayType * Dest,const ArrayType * Source)5428 static bool hasCompatibleArrayTypes(ASTContext &Context, const ArrayType *Dest,
5429 const ArrayType *Source) {
5430 // If the source and destination array types are equivalent, we're
5431 // done.
5432 if (Context.hasSameType(QualType(Dest, 0), QualType(Source, 0)))
5433 return true;
5434
5435 // Make sure that the element types are the same.
5436 if (!Context.hasSameType(Dest->getElementType(), Source->getElementType()))
5437 return false;
5438
5439 // The only mismatch we allow is when the destination is an
5440 // incomplete array type and the source is a constant array type.
5441 return Source->isConstantArrayType() && Dest->isIncompleteArrayType();
5442 }
5443
tryObjCWritebackConversion(Sema & S,InitializationSequence & Sequence,const InitializedEntity & Entity,Expr * Initializer)5444 static bool tryObjCWritebackConversion(Sema &S,
5445 InitializationSequence &Sequence,
5446 const InitializedEntity &Entity,
5447 Expr *Initializer) {
5448 bool ArrayDecay = false;
5449 QualType ArgType = Initializer->getType();
5450 QualType ArgPointee;
5451 if (const ArrayType *ArgArrayType = S.Context.getAsArrayType(ArgType)) {
5452 ArrayDecay = true;
5453 ArgPointee = ArgArrayType->getElementType();
5454 ArgType = S.Context.getPointerType(ArgPointee);
5455 }
5456
5457 // Handle write-back conversion.
5458 QualType ConvertedArgType;
5459 if (!S.isObjCWritebackConversion(ArgType, Entity.getType(),
5460 ConvertedArgType))
5461 return false;
5462
5463 // We should copy unless we're passing to an argument explicitly
5464 // marked 'out'.
5465 bool ShouldCopy = true;
5466 if (ParmVarDecl *param = cast_or_null<ParmVarDecl>(Entity.getDecl()))
5467 ShouldCopy = (param->getObjCDeclQualifier() != ParmVarDecl::OBJC_TQ_Out);
5468
5469 // Do we need an lvalue conversion?
5470 if (ArrayDecay || Initializer->isGLValue()) {
5471 ImplicitConversionSequence ICS;
5472 ICS.setStandard();
5473 ICS.Standard.setAsIdentityConversion();
5474
5475 QualType ResultType;
5476 if (ArrayDecay) {
5477 ICS.Standard.First = ICK_Array_To_Pointer;
5478 ResultType = S.Context.getPointerType(ArgPointee);
5479 } else {
5480 ICS.Standard.First = ICK_Lvalue_To_Rvalue;
5481 ResultType = Initializer->getType().getNonLValueExprType(S.Context);
5482 }
5483
5484 Sequence.AddConversionSequenceStep(ICS, ResultType);
5485 }
5486
5487 Sequence.AddPassByIndirectCopyRestoreStep(Entity.getType(), ShouldCopy);
5488 return true;
5489 }
5490
TryOCLSamplerInitialization(Sema & S,InitializationSequence & Sequence,QualType DestType,Expr * Initializer)5491 static bool TryOCLSamplerInitialization(Sema &S,
5492 InitializationSequence &Sequence,
5493 QualType DestType,
5494 Expr *Initializer) {
5495 if (!S.getLangOpts().OpenCL || !DestType->isSamplerT() ||
5496 (!Initializer->isIntegerConstantExpr(S.Context) &&
5497 !Initializer->getType()->isSamplerT()))
5498 return false;
5499
5500 Sequence.AddOCLSamplerInitStep(DestType);
5501 return true;
5502 }
5503
IsZeroInitializer(Expr * Initializer,Sema & S)5504 static bool IsZeroInitializer(Expr *Initializer, Sema &S) {
5505 return Initializer->isIntegerConstantExpr(S.getASTContext()) &&
5506 (Initializer->EvaluateKnownConstInt(S.getASTContext()) == 0);
5507 }
5508
TryOCLZeroOpaqueTypeInitialization(Sema & S,InitializationSequence & Sequence,QualType DestType,Expr * Initializer)5509 static bool TryOCLZeroOpaqueTypeInitialization(Sema &S,
5510 InitializationSequence &Sequence,
5511 QualType DestType,
5512 Expr *Initializer) {
5513 if (!S.getLangOpts().OpenCL)
5514 return false;
5515
5516 //
5517 // OpenCL 1.2 spec, s6.12.10
5518 //
5519 // The event argument can also be used to associate the
5520 // async_work_group_copy with a previous async copy allowing
5521 // an event to be shared by multiple async copies; otherwise
5522 // event should be zero.
5523 //
5524 if (DestType->isEventT() || DestType->isQueueT()) {
5525 if (!IsZeroInitializer(Initializer, S))
5526 return false;
5527
5528 Sequence.AddOCLZeroOpaqueTypeStep(DestType);
5529 return true;
5530 }
5531
5532 // We should allow zero initialization for all types defined in the
5533 // cl_intel_device_side_avc_motion_estimation extension, except
5534 // intel_sub_group_avc_mce_payload_t and intel_sub_group_avc_mce_result_t.
5535 if (S.getOpenCLOptions().isEnabled(
5536 "cl_intel_device_side_avc_motion_estimation") &&
5537 DestType->isOCLIntelSubgroupAVCType()) {
5538 if (DestType->isOCLIntelSubgroupAVCMcePayloadType() ||
5539 DestType->isOCLIntelSubgroupAVCMceResultType())
5540 return false;
5541 if (!IsZeroInitializer(Initializer, S))
5542 return false;
5543
5544 Sequence.AddOCLZeroOpaqueTypeStep(DestType);
5545 return true;
5546 }
5547
5548 return false;
5549 }
5550
InitializationSequence(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Args,bool TopLevelOfInitList,bool TreatUnavailableAsInvalid)5551 InitializationSequence::InitializationSequence(Sema &S,
5552 const InitializedEntity &Entity,
5553 const InitializationKind &Kind,
5554 MultiExprArg Args,
5555 bool TopLevelOfInitList,
5556 bool TreatUnavailableAsInvalid)
5557 : FailedCandidateSet(Kind.getLocation(), OverloadCandidateSet::CSK_Normal) {
5558 InitializeFrom(S, Entity, Kind, Args, TopLevelOfInitList,
5559 TreatUnavailableAsInvalid);
5560 }
5561
5562 /// Tries to get a FunctionDecl out of `E`. If it succeeds and we can take the
5563 /// address of that function, this returns true. Otherwise, it returns false.
isExprAnUnaddressableFunction(Sema & S,const Expr * E)5564 static bool isExprAnUnaddressableFunction(Sema &S, const Expr *E) {
5565 auto *DRE = dyn_cast<DeclRefExpr>(E);
5566 if (!DRE || !isa<FunctionDecl>(DRE->getDecl()))
5567 return false;
5568
5569 return !S.checkAddressOfFunctionIsAvailable(
5570 cast<FunctionDecl>(DRE->getDecl()));
5571 }
5572
5573 /// Determine whether we can perform an elementwise array copy for this kind
5574 /// of entity.
canPerformArrayCopy(const InitializedEntity & Entity)5575 static bool canPerformArrayCopy(const InitializedEntity &Entity) {
5576 switch (Entity.getKind()) {
5577 case InitializedEntity::EK_LambdaCapture:
5578 // C++ [expr.prim.lambda]p24:
5579 // For array members, the array elements are direct-initialized in
5580 // increasing subscript order.
5581 return true;
5582
5583 case InitializedEntity::EK_Variable:
5584 // C++ [dcl.decomp]p1:
5585 // [...] each element is copy-initialized or direct-initialized from the
5586 // corresponding element of the assignment-expression [...]
5587 return isa<DecompositionDecl>(Entity.getDecl());
5588
5589 case InitializedEntity::EK_Member:
5590 // C++ [class.copy.ctor]p14:
5591 // - if the member is an array, each element is direct-initialized with
5592 // the corresponding subobject of x
5593 return Entity.isImplicitMemberInitializer();
5594
5595 case InitializedEntity::EK_ArrayElement:
5596 // All the above cases are intended to apply recursively, even though none
5597 // of them actually say that.
5598 if (auto *E = Entity.getParent())
5599 return canPerformArrayCopy(*E);
5600 break;
5601
5602 default:
5603 break;
5604 }
5605
5606 return false;
5607 }
5608
InitializeFrom(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Args,bool TopLevelOfInitList,bool TreatUnavailableAsInvalid)5609 void InitializationSequence::InitializeFrom(Sema &S,
5610 const InitializedEntity &Entity,
5611 const InitializationKind &Kind,
5612 MultiExprArg Args,
5613 bool TopLevelOfInitList,
5614 bool TreatUnavailableAsInvalid) {
5615 ASTContext &Context = S.Context;
5616
5617 // Eliminate non-overload placeholder types in the arguments. We
5618 // need to do this before checking whether types are dependent
5619 // because lowering a pseudo-object expression might well give us
5620 // something of dependent type.
5621 for (unsigned I = 0, E = Args.size(); I != E; ++I)
5622 if (Args[I]->getType()->isNonOverloadPlaceholderType()) {
5623 // FIXME: should we be doing this here?
5624 ExprResult result = S.CheckPlaceholderExpr(Args[I]);
5625 if (result.isInvalid()) {
5626 SetFailed(FK_PlaceholderType);
5627 return;
5628 }
5629 Args[I] = result.get();
5630 }
5631
5632 // C++0x [dcl.init]p16:
5633 // The semantics of initializers are as follows. The destination type is
5634 // the type of the object or reference being initialized and the source
5635 // type is the type of the initializer expression. The source type is not
5636 // defined when the initializer is a braced-init-list or when it is a
5637 // parenthesized list of expressions.
5638 QualType DestType = Entity.getType();
5639
5640 if (DestType->isDependentType() ||
5641 Expr::hasAnyTypeDependentArguments(Args)) {
5642 SequenceKind = DependentSequence;
5643 return;
5644 }
5645
5646 // Almost everything is a normal sequence.
5647 setSequenceKind(NormalSequence);
5648
5649 QualType SourceType;
5650 Expr *Initializer = nullptr;
5651 if (Args.size() == 1) {
5652 Initializer = Args[0];
5653 if (S.getLangOpts().ObjC) {
5654 if (S.CheckObjCBridgeRelatedConversions(Initializer->getBeginLoc(),
5655 DestType, Initializer->getType(),
5656 Initializer) ||
5657 S.CheckConversionToObjCLiteral(DestType, Initializer))
5658 Args[0] = Initializer;
5659 }
5660 if (!isa<InitListExpr>(Initializer))
5661 SourceType = Initializer->getType();
5662 }
5663
5664 // - If the initializer is a (non-parenthesized) braced-init-list, the
5665 // object is list-initialized (8.5.4).
5666 if (Kind.getKind() != InitializationKind::IK_Direct) {
5667 if (InitListExpr *InitList = dyn_cast_or_null<InitListExpr>(Initializer)) {
5668 TryListInitialization(S, Entity, Kind, InitList, *this,
5669 TreatUnavailableAsInvalid);
5670 return;
5671 }
5672 }
5673
5674 // - If the destination type is a reference type, see 8.5.3.
5675 if (DestType->isReferenceType()) {
5676 // C++0x [dcl.init.ref]p1:
5677 // A variable declared to be a T& or T&&, that is, "reference to type T"
5678 // (8.3.2), shall be initialized by an object, or function, of type T or
5679 // by an object that can be converted into a T.
5680 // (Therefore, multiple arguments are not permitted.)
5681 if (Args.size() != 1)
5682 SetFailed(FK_TooManyInitsForReference);
5683 // C++17 [dcl.init.ref]p5:
5684 // A reference [...] is initialized by an expression [...] as follows:
5685 // If the initializer is not an expression, presumably we should reject,
5686 // but the standard fails to actually say so.
5687 else if (isa<InitListExpr>(Args[0]))
5688 SetFailed(FK_ParenthesizedListInitForReference);
5689 else
5690 TryReferenceInitialization(S, Entity, Kind, Args[0], *this);
5691 return;
5692 }
5693
5694 // - If the initializer is (), the object is value-initialized.
5695 if (Kind.getKind() == InitializationKind::IK_Value ||
5696 (Kind.getKind() == InitializationKind::IK_Direct && Args.empty())) {
5697 TryValueInitialization(S, Entity, Kind, *this);
5698 return;
5699 }
5700
5701 // Handle default initialization.
5702 if (Kind.getKind() == InitializationKind::IK_Default) {
5703 TryDefaultInitialization(S, Entity, Kind, *this);
5704 return;
5705 }
5706
5707 // - If the destination type is an array of characters, an array of
5708 // char16_t, an array of char32_t, or an array of wchar_t, and the
5709 // initializer is a string literal, see 8.5.2.
5710 // - Otherwise, if the destination type is an array, the program is
5711 // ill-formed.
5712 if (const ArrayType *DestAT = Context.getAsArrayType(DestType)) {
5713 if (Initializer && isa<VariableArrayType>(DestAT)) {
5714 SetFailed(FK_VariableLengthArrayHasInitializer);
5715 return;
5716 }
5717
5718 if (Initializer) {
5719 switch (IsStringInit(Initializer, DestAT, Context)) {
5720 case SIF_None:
5721 TryStringLiteralInitialization(S, Entity, Kind, Initializer, *this);
5722 return;
5723 case SIF_NarrowStringIntoWideChar:
5724 SetFailed(FK_NarrowStringIntoWideCharArray);
5725 return;
5726 case SIF_WideStringIntoChar:
5727 SetFailed(FK_WideStringIntoCharArray);
5728 return;
5729 case SIF_IncompatWideStringIntoWideChar:
5730 SetFailed(FK_IncompatWideStringIntoWideChar);
5731 return;
5732 case SIF_PlainStringIntoUTF8Char:
5733 SetFailed(FK_PlainStringIntoUTF8Char);
5734 return;
5735 case SIF_UTF8StringIntoPlainChar:
5736 SetFailed(FK_UTF8StringIntoPlainChar);
5737 return;
5738 case SIF_Other:
5739 break;
5740 }
5741 }
5742
5743 // Some kinds of initialization permit an array to be initialized from
5744 // another array of the same type, and perform elementwise initialization.
5745 if (Initializer && isa<ConstantArrayType>(DestAT) &&
5746 S.Context.hasSameUnqualifiedType(Initializer->getType(),
5747 Entity.getType()) &&
5748 canPerformArrayCopy(Entity)) {
5749 // If source is a prvalue, use it directly.
5750 if (Initializer->getValueKind() == VK_RValue) {
5751 AddArrayInitStep(DestType, /*IsGNUExtension*/false);
5752 return;
5753 }
5754
5755 // Emit element-at-a-time copy loop.
5756 InitializedEntity Element =
5757 InitializedEntity::InitializeElement(S.Context, 0, Entity);
5758 QualType InitEltT =
5759 Context.getAsArrayType(Initializer->getType())->getElementType();
5760 OpaqueValueExpr OVE(Initializer->getExprLoc(), InitEltT,
5761 Initializer->getValueKind(),
5762 Initializer->getObjectKind());
5763 Expr *OVEAsExpr = &OVE;
5764 InitializeFrom(S, Element, Kind, OVEAsExpr, TopLevelOfInitList,
5765 TreatUnavailableAsInvalid);
5766 if (!Failed())
5767 AddArrayInitLoopStep(Entity.getType(), InitEltT);
5768 return;
5769 }
5770
5771 // Note: as an GNU C extension, we allow initialization of an
5772 // array from a compound literal that creates an array of the same
5773 // type, so long as the initializer has no side effects.
5774 if (!S.getLangOpts().CPlusPlus && Initializer &&
5775 isa<CompoundLiteralExpr>(Initializer->IgnoreParens()) &&
5776 Initializer->getType()->isArrayType()) {
5777 const ArrayType *SourceAT
5778 = Context.getAsArrayType(Initializer->getType());
5779 if (!hasCompatibleArrayTypes(S.Context, DestAT, SourceAT))
5780 SetFailed(FK_ArrayTypeMismatch);
5781 else if (Initializer->HasSideEffects(S.Context))
5782 SetFailed(FK_NonConstantArrayInit);
5783 else {
5784 AddArrayInitStep(DestType, /*IsGNUExtension*/true);
5785 }
5786 }
5787 // Note: as a GNU C++ extension, we allow list-initialization of a
5788 // class member of array type from a parenthesized initializer list.
5789 else if (S.getLangOpts().CPlusPlus &&
5790 Entity.getKind() == InitializedEntity::EK_Member &&
5791 Initializer && isa<InitListExpr>(Initializer)) {
5792 TryListInitialization(S, Entity, Kind, cast<InitListExpr>(Initializer),
5793 *this, TreatUnavailableAsInvalid);
5794 AddParenthesizedArrayInitStep(DestType);
5795 } else if (DestAT->getElementType()->isCharType())
5796 SetFailed(FK_ArrayNeedsInitListOrStringLiteral);
5797 else if (IsWideCharCompatible(DestAT->getElementType(), Context))
5798 SetFailed(FK_ArrayNeedsInitListOrWideStringLiteral);
5799 else
5800 SetFailed(FK_ArrayNeedsInitList);
5801
5802 return;
5803 }
5804
5805 // Determine whether we should consider writeback conversions for
5806 // Objective-C ARC.
5807 bool allowObjCWritebackConversion = S.getLangOpts().ObjCAutoRefCount &&
5808 Entity.isParameterKind();
5809
5810 if (TryOCLSamplerInitialization(S, *this, DestType, Initializer))
5811 return;
5812
5813 // We're at the end of the line for C: it's either a write-back conversion
5814 // or it's a C assignment. There's no need to check anything else.
5815 if (!S.getLangOpts().CPlusPlus) {
5816 // If allowed, check whether this is an Objective-C writeback conversion.
5817 if (allowObjCWritebackConversion &&
5818 tryObjCWritebackConversion(S, *this, Entity, Initializer)) {
5819 return;
5820 }
5821
5822 if (TryOCLZeroOpaqueTypeInitialization(S, *this, DestType, Initializer))
5823 return;
5824
5825 // Handle initialization in C
5826 AddCAssignmentStep(DestType);
5827 MaybeProduceObjCObject(S, *this, Entity);
5828 return;
5829 }
5830
5831 assert(S.getLangOpts().CPlusPlus);
5832
5833 // - If the destination type is a (possibly cv-qualified) class type:
5834 if (DestType->isRecordType()) {
5835 // - If the initialization is direct-initialization, or if it is
5836 // copy-initialization where the cv-unqualified version of the
5837 // source type is the same class as, or a derived class of, the
5838 // class of the destination, constructors are considered. [...]
5839 if (Kind.getKind() == InitializationKind::IK_Direct ||
5840 (Kind.getKind() == InitializationKind::IK_Copy &&
5841 (Context.hasSameUnqualifiedType(SourceType, DestType) ||
5842 S.IsDerivedFrom(Initializer->getBeginLoc(), SourceType, DestType))))
5843 TryConstructorInitialization(S, Entity, Kind, Args,
5844 DestType, DestType, *this);
5845 // - Otherwise (i.e., for the remaining copy-initialization cases),
5846 // user-defined conversion sequences that can convert from the source
5847 // type to the destination type or (when a conversion function is
5848 // used) to a derived class thereof are enumerated as described in
5849 // 13.3.1.4, and the best one is chosen through overload resolution
5850 // (13.3).
5851 else
5852 TryUserDefinedConversion(S, DestType, Kind, Initializer, *this,
5853 TopLevelOfInitList);
5854 return;
5855 }
5856
5857 assert(Args.size() >= 1 && "Zero-argument case handled above");
5858
5859 // The remaining cases all need a source type.
5860 if (Args.size() > 1) {
5861 SetFailed(FK_TooManyInitsForScalar);
5862 return;
5863 } else if (isa<InitListExpr>(Args[0])) {
5864 SetFailed(FK_ParenthesizedListInitForScalar);
5865 return;
5866 }
5867
5868 // - Otherwise, if the source type is a (possibly cv-qualified) class
5869 // type, conversion functions are considered.
5870 if (!SourceType.isNull() && SourceType->isRecordType()) {
5871 // For a conversion to _Atomic(T) from either T or a class type derived
5872 // from T, initialize the T object then convert to _Atomic type.
5873 bool NeedAtomicConversion = false;
5874 if (const AtomicType *Atomic = DestType->getAs<AtomicType>()) {
5875 if (Context.hasSameUnqualifiedType(SourceType, Atomic->getValueType()) ||
5876 S.IsDerivedFrom(Initializer->getBeginLoc(), SourceType,
5877 Atomic->getValueType())) {
5878 DestType = Atomic->getValueType();
5879 NeedAtomicConversion = true;
5880 }
5881 }
5882
5883 TryUserDefinedConversion(S, DestType, Kind, Initializer, *this,
5884 TopLevelOfInitList);
5885 MaybeProduceObjCObject(S, *this, Entity);
5886 if (!Failed() && NeedAtomicConversion)
5887 AddAtomicConversionStep(Entity.getType());
5888 return;
5889 }
5890
5891 // - Otherwise, if the initialization is direct-initialization, the source
5892 // type is std::nullptr_t, and the destination type is bool, the initial
5893 // value of the object being initialized is false.
5894 if (!SourceType.isNull() && SourceType->isNullPtrType() &&
5895 DestType->isBooleanType() &&
5896 Kind.getKind() == InitializationKind::IK_Direct) {
5897 AddConversionSequenceStep(
5898 ImplicitConversionSequence::getNullptrToBool(SourceType, DestType,
5899 Initializer->isGLValue()),
5900 DestType);
5901 return;
5902 }
5903
5904 // - Otherwise, the initial value of the object being initialized is the
5905 // (possibly converted) value of the initializer expression. Standard
5906 // conversions (Clause 4) will be used, if necessary, to convert the
5907 // initializer expression to the cv-unqualified version of the
5908 // destination type; no user-defined conversions are considered.
5909
5910 ImplicitConversionSequence ICS
5911 = S.TryImplicitConversion(Initializer, DestType,
5912 /*SuppressUserConversions*/true,
5913 Sema::AllowedExplicit::None,
5914 /*InOverloadResolution*/ false,
5915 /*CStyle=*/Kind.isCStyleOrFunctionalCast(),
5916 allowObjCWritebackConversion);
5917
5918 if (ICS.isStandard() &&
5919 ICS.Standard.Second == ICK_Writeback_Conversion) {
5920 // Objective-C ARC writeback conversion.
5921
5922 // We should copy unless we're passing to an argument explicitly
5923 // marked 'out'.
5924 bool ShouldCopy = true;
5925 if (ParmVarDecl *Param = cast_or_null<ParmVarDecl>(Entity.getDecl()))
5926 ShouldCopy = (Param->getObjCDeclQualifier() != ParmVarDecl::OBJC_TQ_Out);
5927
5928 // If there was an lvalue adjustment, add it as a separate conversion.
5929 if (ICS.Standard.First == ICK_Array_To_Pointer ||
5930 ICS.Standard.First == ICK_Lvalue_To_Rvalue) {
5931 ImplicitConversionSequence LvalueICS;
5932 LvalueICS.setStandard();
5933 LvalueICS.Standard.setAsIdentityConversion();
5934 LvalueICS.Standard.setAllToTypes(ICS.Standard.getToType(0));
5935 LvalueICS.Standard.First = ICS.Standard.First;
5936 AddConversionSequenceStep(LvalueICS, ICS.Standard.getToType(0));
5937 }
5938
5939 AddPassByIndirectCopyRestoreStep(DestType, ShouldCopy);
5940 } else if (ICS.isBad()) {
5941 DeclAccessPair dap;
5942 if (isLibstdcxxPointerReturnFalseHack(S, Entity, Initializer)) {
5943 AddZeroInitializationStep(Entity.getType());
5944 } else if (Initializer->getType() == Context.OverloadTy &&
5945 !S.ResolveAddressOfOverloadedFunction(Initializer, DestType,
5946 false, dap))
5947 SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
5948 else if (Initializer->getType()->isFunctionType() &&
5949 isExprAnUnaddressableFunction(S, Initializer))
5950 SetFailed(InitializationSequence::FK_AddressOfUnaddressableFunction);
5951 else
5952 SetFailed(InitializationSequence::FK_ConversionFailed);
5953 } else {
5954 AddConversionSequenceStep(ICS, DestType, TopLevelOfInitList);
5955
5956 MaybeProduceObjCObject(S, *this, Entity);
5957 }
5958 }
5959
~InitializationSequence()5960 InitializationSequence::~InitializationSequence() {
5961 for (auto &S : Steps)
5962 S.Destroy();
5963 }
5964
5965 //===----------------------------------------------------------------------===//
5966 // Perform initialization
5967 //===----------------------------------------------------------------------===//
5968 static Sema::AssignmentAction
getAssignmentAction(const InitializedEntity & Entity,bool Diagnose=false)5969 getAssignmentAction(const InitializedEntity &Entity, bool Diagnose = false) {
5970 switch(Entity.getKind()) {
5971 case InitializedEntity::EK_Variable:
5972 case InitializedEntity::EK_New:
5973 case InitializedEntity::EK_Exception:
5974 case InitializedEntity::EK_Base:
5975 case InitializedEntity::EK_Delegating:
5976 return Sema::AA_Initializing;
5977
5978 case InitializedEntity::EK_Parameter:
5979 if (Entity.getDecl() &&
5980 isa<ObjCMethodDecl>(Entity.getDecl()->getDeclContext()))
5981 return Sema::AA_Sending;
5982
5983 return Sema::AA_Passing;
5984
5985 case InitializedEntity::EK_Parameter_CF_Audited:
5986 if (Entity.getDecl() &&
5987 isa<ObjCMethodDecl>(Entity.getDecl()->getDeclContext()))
5988 return Sema::AA_Sending;
5989
5990 return !Diagnose ? Sema::AA_Passing : Sema::AA_Passing_CFAudited;
5991
5992 case InitializedEntity::EK_Result:
5993 case InitializedEntity::EK_StmtExprResult: // FIXME: Not quite right.
5994 return Sema::AA_Returning;
5995
5996 case InitializedEntity::EK_Temporary:
5997 case InitializedEntity::EK_RelatedResult:
5998 // FIXME: Can we tell apart casting vs. converting?
5999 return Sema::AA_Casting;
6000
6001 case InitializedEntity::EK_Member:
6002 case InitializedEntity::EK_Binding:
6003 case InitializedEntity::EK_ArrayElement:
6004 case InitializedEntity::EK_VectorElement:
6005 case InitializedEntity::EK_ComplexElement:
6006 case InitializedEntity::EK_BlockElement:
6007 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6008 case InitializedEntity::EK_LambdaCapture:
6009 case InitializedEntity::EK_CompoundLiteralInit:
6010 return Sema::AA_Initializing;
6011 }
6012
6013 llvm_unreachable("Invalid EntityKind!");
6014 }
6015
6016 /// Whether we should bind a created object as a temporary when
6017 /// initializing the given entity.
shouldBindAsTemporary(const InitializedEntity & Entity)6018 static bool shouldBindAsTemporary(const InitializedEntity &Entity) {
6019 switch (Entity.getKind()) {
6020 case InitializedEntity::EK_ArrayElement:
6021 case InitializedEntity::EK_Member:
6022 case InitializedEntity::EK_Result:
6023 case InitializedEntity::EK_StmtExprResult:
6024 case InitializedEntity::EK_New:
6025 case InitializedEntity::EK_Variable:
6026 case InitializedEntity::EK_Base:
6027 case InitializedEntity::EK_Delegating:
6028 case InitializedEntity::EK_VectorElement:
6029 case InitializedEntity::EK_ComplexElement:
6030 case InitializedEntity::EK_Exception:
6031 case InitializedEntity::EK_BlockElement:
6032 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6033 case InitializedEntity::EK_LambdaCapture:
6034 case InitializedEntity::EK_CompoundLiteralInit:
6035 return false;
6036
6037 case InitializedEntity::EK_Parameter:
6038 case InitializedEntity::EK_Parameter_CF_Audited:
6039 case InitializedEntity::EK_Temporary:
6040 case InitializedEntity::EK_RelatedResult:
6041 case InitializedEntity::EK_Binding:
6042 return true;
6043 }
6044
6045 llvm_unreachable("missed an InitializedEntity kind?");
6046 }
6047
6048 /// Whether the given entity, when initialized with an object
6049 /// created for that initialization, requires destruction.
shouldDestroyEntity(const InitializedEntity & Entity)6050 static bool shouldDestroyEntity(const InitializedEntity &Entity) {
6051 switch (Entity.getKind()) {
6052 case InitializedEntity::EK_Result:
6053 case InitializedEntity::EK_StmtExprResult:
6054 case InitializedEntity::EK_New:
6055 case InitializedEntity::EK_Base:
6056 case InitializedEntity::EK_Delegating:
6057 case InitializedEntity::EK_VectorElement:
6058 case InitializedEntity::EK_ComplexElement:
6059 case InitializedEntity::EK_BlockElement:
6060 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6061 case InitializedEntity::EK_LambdaCapture:
6062 return false;
6063
6064 case InitializedEntity::EK_Member:
6065 case InitializedEntity::EK_Binding:
6066 case InitializedEntity::EK_Variable:
6067 case InitializedEntity::EK_Parameter:
6068 case InitializedEntity::EK_Parameter_CF_Audited:
6069 case InitializedEntity::EK_Temporary:
6070 case InitializedEntity::EK_ArrayElement:
6071 case InitializedEntity::EK_Exception:
6072 case InitializedEntity::EK_CompoundLiteralInit:
6073 case InitializedEntity::EK_RelatedResult:
6074 return true;
6075 }
6076
6077 llvm_unreachable("missed an InitializedEntity kind?");
6078 }
6079
6080 /// Get the location at which initialization diagnostics should appear.
getInitializationLoc(const InitializedEntity & Entity,Expr * Initializer)6081 static SourceLocation getInitializationLoc(const InitializedEntity &Entity,
6082 Expr *Initializer) {
6083 switch (Entity.getKind()) {
6084 case InitializedEntity::EK_Result:
6085 case InitializedEntity::EK_StmtExprResult:
6086 return Entity.getReturnLoc();
6087
6088 case InitializedEntity::EK_Exception:
6089 return Entity.getThrowLoc();
6090
6091 case InitializedEntity::EK_Variable:
6092 case InitializedEntity::EK_Binding:
6093 return Entity.getDecl()->getLocation();
6094
6095 case InitializedEntity::EK_LambdaCapture:
6096 return Entity.getCaptureLoc();
6097
6098 case InitializedEntity::EK_ArrayElement:
6099 case InitializedEntity::EK_Member:
6100 case InitializedEntity::EK_Parameter:
6101 case InitializedEntity::EK_Parameter_CF_Audited:
6102 case InitializedEntity::EK_Temporary:
6103 case InitializedEntity::EK_New:
6104 case InitializedEntity::EK_Base:
6105 case InitializedEntity::EK_Delegating:
6106 case InitializedEntity::EK_VectorElement:
6107 case InitializedEntity::EK_ComplexElement:
6108 case InitializedEntity::EK_BlockElement:
6109 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6110 case InitializedEntity::EK_CompoundLiteralInit:
6111 case InitializedEntity::EK_RelatedResult:
6112 return Initializer->getBeginLoc();
6113 }
6114 llvm_unreachable("missed an InitializedEntity kind?");
6115 }
6116
6117 /// Make a (potentially elidable) temporary copy of the object
6118 /// provided by the given initializer by calling the appropriate copy
6119 /// constructor.
6120 ///
6121 /// \param S The Sema object used for type-checking.
6122 ///
6123 /// \param T The type of the temporary object, which must either be
6124 /// the type of the initializer expression or a superclass thereof.
6125 ///
6126 /// \param Entity The entity being initialized.
6127 ///
6128 /// \param CurInit The initializer expression.
6129 ///
6130 /// \param IsExtraneousCopy Whether this is an "extraneous" copy that
6131 /// is permitted in C++03 (but not C++0x) when binding a reference to
6132 /// an rvalue.
6133 ///
6134 /// \returns An expression that copies the initializer expression into
6135 /// a temporary object, or an error expression if a copy could not be
6136 /// created.
CopyObject(Sema & S,QualType T,const InitializedEntity & Entity,ExprResult CurInit,bool IsExtraneousCopy)6137 static ExprResult CopyObject(Sema &S,
6138 QualType T,
6139 const InitializedEntity &Entity,
6140 ExprResult CurInit,
6141 bool IsExtraneousCopy) {
6142 if (CurInit.isInvalid())
6143 return CurInit;
6144 // Determine which class type we're copying to.
6145 Expr *CurInitExpr = (Expr *)CurInit.get();
6146 CXXRecordDecl *Class = nullptr;
6147 if (const RecordType *Record = T->getAs<RecordType>())
6148 Class = cast<CXXRecordDecl>(Record->getDecl());
6149 if (!Class)
6150 return CurInit;
6151
6152 SourceLocation Loc = getInitializationLoc(Entity, CurInit.get());
6153
6154 // Make sure that the type we are copying is complete.
6155 if (S.RequireCompleteType(Loc, T, diag::err_temp_copy_incomplete))
6156 return CurInit;
6157
6158 // Perform overload resolution using the class's constructors. Per
6159 // C++11 [dcl.init]p16, second bullet for class types, this initialization
6160 // is direct-initialization.
6161 OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
6162 DeclContext::lookup_result Ctors = S.LookupConstructors(Class);
6163
6164 OverloadCandidateSet::iterator Best;
6165 switch (ResolveConstructorOverload(
6166 S, Loc, CurInitExpr, CandidateSet, T, Ctors, Best,
6167 /*CopyInitializing=*/false, /*AllowExplicit=*/true,
6168 /*OnlyListConstructors=*/false, /*IsListInit=*/false,
6169 /*SecondStepOfCopyInit=*/true)) {
6170 case OR_Success:
6171 break;
6172
6173 case OR_No_Viable_Function:
6174 CandidateSet.NoteCandidates(
6175 PartialDiagnosticAt(
6176 Loc, S.PDiag(IsExtraneousCopy && !S.isSFINAEContext()
6177 ? diag::ext_rvalue_to_reference_temp_copy_no_viable
6178 : diag::err_temp_copy_no_viable)
6179 << (int)Entity.getKind() << CurInitExpr->getType()
6180 << CurInitExpr->getSourceRange()),
6181 S, OCD_AllCandidates, CurInitExpr);
6182 if (!IsExtraneousCopy || S.isSFINAEContext())
6183 return ExprError();
6184 return CurInit;
6185
6186 case OR_Ambiguous:
6187 CandidateSet.NoteCandidates(
6188 PartialDiagnosticAt(Loc, S.PDiag(diag::err_temp_copy_ambiguous)
6189 << (int)Entity.getKind()
6190 << CurInitExpr->getType()
6191 << CurInitExpr->getSourceRange()),
6192 S, OCD_AmbiguousCandidates, CurInitExpr);
6193 return ExprError();
6194
6195 case OR_Deleted:
6196 S.Diag(Loc, diag::err_temp_copy_deleted)
6197 << (int)Entity.getKind() << CurInitExpr->getType()
6198 << CurInitExpr->getSourceRange();
6199 S.NoteDeletedFunction(Best->Function);
6200 return ExprError();
6201 }
6202
6203 bool HadMultipleCandidates = CandidateSet.size() > 1;
6204
6205 CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Best->Function);
6206 SmallVector<Expr*, 8> ConstructorArgs;
6207 CurInit.get(); // Ownership transferred into MultiExprArg, below.
6208
6209 S.CheckConstructorAccess(Loc, Constructor, Best->FoundDecl, Entity,
6210 IsExtraneousCopy);
6211
6212 if (IsExtraneousCopy) {
6213 // If this is a totally extraneous copy for C++03 reference
6214 // binding purposes, just return the original initialization
6215 // expression. We don't generate an (elided) copy operation here
6216 // because doing so would require us to pass down a flag to avoid
6217 // infinite recursion, where each step adds another extraneous,
6218 // elidable copy.
6219
6220 // Instantiate the default arguments of any extra parameters in
6221 // the selected copy constructor, as if we were going to create a
6222 // proper call to the copy constructor.
6223 for (unsigned I = 1, N = Constructor->getNumParams(); I != N; ++I) {
6224 ParmVarDecl *Parm = Constructor->getParamDecl(I);
6225 if (S.RequireCompleteType(Loc, Parm->getType(),
6226 diag::err_call_incomplete_argument))
6227 break;
6228
6229 // Build the default argument expression; we don't actually care
6230 // if this succeeds or not, because this routine will complain
6231 // if there was a problem.
6232 S.BuildCXXDefaultArgExpr(Loc, Constructor, Parm);
6233 }
6234
6235 return CurInitExpr;
6236 }
6237
6238 // Determine the arguments required to actually perform the
6239 // constructor call (we might have derived-to-base conversions, or
6240 // the copy constructor may have default arguments).
6241 if (S.CompleteConstructorCall(Constructor, CurInitExpr, Loc, ConstructorArgs))
6242 return ExprError();
6243
6244 // C++0x [class.copy]p32:
6245 // When certain criteria are met, an implementation is allowed to
6246 // omit the copy/move construction of a class object, even if the
6247 // copy/move constructor and/or destructor for the object have
6248 // side effects. [...]
6249 // - when a temporary class object that has not been bound to a
6250 // reference (12.2) would be copied/moved to a class object
6251 // with the same cv-unqualified type, the copy/move operation
6252 // can be omitted by constructing the temporary object
6253 // directly into the target of the omitted copy/move
6254 //
6255 // Note that the other three bullets are handled elsewhere. Copy
6256 // elision for return statements and throw expressions are handled as part
6257 // of constructor initialization, while copy elision for exception handlers
6258 // is handled by the run-time.
6259 //
6260 // FIXME: If the function parameter is not the same type as the temporary, we
6261 // should still be able to elide the copy, but we don't have a way to
6262 // represent in the AST how much should be elided in this case.
6263 bool Elidable =
6264 CurInitExpr->isTemporaryObject(S.Context, Class) &&
6265 S.Context.hasSameUnqualifiedType(
6266 Best->Function->getParamDecl(0)->getType().getNonReferenceType(),
6267 CurInitExpr->getType());
6268
6269 // Actually perform the constructor call.
6270 CurInit = S.BuildCXXConstructExpr(Loc, T, Best->FoundDecl, Constructor,
6271 Elidable,
6272 ConstructorArgs,
6273 HadMultipleCandidates,
6274 /*ListInit*/ false,
6275 /*StdInitListInit*/ false,
6276 /*ZeroInit*/ false,
6277 CXXConstructExpr::CK_Complete,
6278 SourceRange());
6279
6280 // If we're supposed to bind temporaries, do so.
6281 if (!CurInit.isInvalid() && shouldBindAsTemporary(Entity))
6282 CurInit = S.MaybeBindToTemporary(CurInit.getAs<Expr>());
6283 return CurInit;
6284 }
6285
6286 /// Check whether elidable copy construction for binding a reference to
6287 /// a temporary would have succeeded if we were building in C++98 mode, for
6288 /// -Wc++98-compat.
CheckCXX98CompatAccessibleCopy(Sema & S,const InitializedEntity & Entity,Expr * CurInitExpr)6289 static void CheckCXX98CompatAccessibleCopy(Sema &S,
6290 const InitializedEntity &Entity,
6291 Expr *CurInitExpr) {
6292 assert(S.getLangOpts().CPlusPlus11);
6293
6294 const RecordType *Record = CurInitExpr->getType()->getAs<RecordType>();
6295 if (!Record)
6296 return;
6297
6298 SourceLocation Loc = getInitializationLoc(Entity, CurInitExpr);
6299 if (S.Diags.isIgnored(diag::warn_cxx98_compat_temp_copy, Loc))
6300 return;
6301
6302 // Find constructors which would have been considered.
6303 OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
6304 DeclContext::lookup_result Ctors =
6305 S.LookupConstructors(cast<CXXRecordDecl>(Record->getDecl()));
6306
6307 // Perform overload resolution.
6308 OverloadCandidateSet::iterator Best;
6309 OverloadingResult OR = ResolveConstructorOverload(
6310 S, Loc, CurInitExpr, CandidateSet, CurInitExpr->getType(), Ctors, Best,
6311 /*CopyInitializing=*/false, /*AllowExplicit=*/true,
6312 /*OnlyListConstructors=*/false, /*IsListInit=*/false,
6313 /*SecondStepOfCopyInit=*/true);
6314
6315 PartialDiagnostic Diag = S.PDiag(diag::warn_cxx98_compat_temp_copy)
6316 << OR << (int)Entity.getKind() << CurInitExpr->getType()
6317 << CurInitExpr->getSourceRange();
6318
6319 switch (OR) {
6320 case OR_Success:
6321 S.CheckConstructorAccess(Loc, cast<CXXConstructorDecl>(Best->Function),
6322 Best->FoundDecl, Entity, Diag);
6323 // FIXME: Check default arguments as far as that's possible.
6324 break;
6325
6326 case OR_No_Viable_Function:
6327 CandidateSet.NoteCandidates(PartialDiagnosticAt(Loc, Diag), S,
6328 OCD_AllCandidates, CurInitExpr);
6329 break;
6330
6331 case OR_Ambiguous:
6332 CandidateSet.NoteCandidates(PartialDiagnosticAt(Loc, Diag), S,
6333 OCD_AmbiguousCandidates, CurInitExpr);
6334 break;
6335
6336 case OR_Deleted:
6337 S.Diag(Loc, Diag);
6338 S.NoteDeletedFunction(Best->Function);
6339 break;
6340 }
6341 }
6342
PrintInitLocationNote(Sema & S,const InitializedEntity & Entity)6343 void InitializationSequence::PrintInitLocationNote(Sema &S,
6344 const InitializedEntity &Entity) {
6345 if (Entity.isParameterKind() && Entity.getDecl()) {
6346 if (Entity.getDecl()->getLocation().isInvalid())
6347 return;
6348
6349 if (Entity.getDecl()->getDeclName())
6350 S.Diag(Entity.getDecl()->getLocation(), diag::note_parameter_named_here)
6351 << Entity.getDecl()->getDeclName();
6352 else
6353 S.Diag(Entity.getDecl()->getLocation(), diag::note_parameter_here);
6354 }
6355 else if (Entity.getKind() == InitializedEntity::EK_RelatedResult &&
6356 Entity.getMethodDecl())
6357 S.Diag(Entity.getMethodDecl()->getLocation(),
6358 diag::note_method_return_type_change)
6359 << Entity.getMethodDecl()->getDeclName();
6360 }
6361
6362 /// Returns true if the parameters describe a constructor initialization of
6363 /// an explicit temporary object, e.g. "Point(x, y)".
isExplicitTemporary(const InitializedEntity & Entity,const InitializationKind & Kind,unsigned NumArgs)6364 static bool isExplicitTemporary(const InitializedEntity &Entity,
6365 const InitializationKind &Kind,
6366 unsigned NumArgs) {
6367 switch (Entity.getKind()) {
6368 case InitializedEntity::EK_Temporary:
6369 case InitializedEntity::EK_CompoundLiteralInit:
6370 case InitializedEntity::EK_RelatedResult:
6371 break;
6372 default:
6373 return false;
6374 }
6375
6376 switch (Kind.getKind()) {
6377 case InitializationKind::IK_DirectList:
6378 return true;
6379 // FIXME: Hack to work around cast weirdness.
6380 case InitializationKind::IK_Direct:
6381 case InitializationKind::IK_Value:
6382 return NumArgs != 1;
6383 default:
6384 return false;
6385 }
6386 }
6387
6388 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)6389 PerformConstructorInitialization(Sema &S,
6390 const InitializedEntity &Entity,
6391 const InitializationKind &Kind,
6392 MultiExprArg Args,
6393 const InitializationSequence::Step& Step,
6394 bool &ConstructorInitRequiresZeroInit,
6395 bool IsListInitialization,
6396 bool IsStdInitListInitialization,
6397 SourceLocation LBraceLoc,
6398 SourceLocation RBraceLoc) {
6399 unsigned NumArgs = Args.size();
6400 CXXConstructorDecl *Constructor
6401 = cast<CXXConstructorDecl>(Step.Function.Function);
6402 bool HadMultipleCandidates = Step.Function.HadMultipleCandidates;
6403
6404 // Build a call to the selected constructor.
6405 SmallVector<Expr*, 8> ConstructorArgs;
6406 SourceLocation Loc = (Kind.isCopyInit() && Kind.getEqualLoc().isValid())
6407 ? Kind.getEqualLoc()
6408 : Kind.getLocation();
6409
6410 if (Kind.getKind() == InitializationKind::IK_Default) {
6411 // Force even a trivial, implicit default constructor to be
6412 // semantically checked. We do this explicitly because we don't build
6413 // the definition for completely trivial constructors.
6414 assert(Constructor->getParent() && "No parent class for constructor.");
6415 if (Constructor->isDefaulted() && Constructor->isDefaultConstructor() &&
6416 Constructor->isTrivial() && !Constructor->isUsed(false)) {
6417 S.runWithSufficientStackSpace(Loc, [&] {
6418 S.DefineImplicitDefaultConstructor(Loc, Constructor);
6419 });
6420 }
6421 }
6422
6423 ExprResult CurInit((Expr *)nullptr);
6424
6425 // C++ [over.match.copy]p1:
6426 // - When initializing a temporary to be bound to the first parameter
6427 // of a constructor that takes a reference to possibly cv-qualified
6428 // T as its first argument, called with a single argument in the
6429 // context of direct-initialization, explicit conversion functions
6430 // are also considered.
6431 bool AllowExplicitConv =
6432 Kind.AllowExplicit() && !Kind.isCopyInit() && Args.size() == 1 &&
6433 hasCopyOrMoveCtorParam(S.Context,
6434 getConstructorInfo(Step.Function.FoundDecl));
6435
6436 // Determine the arguments required to actually perform the constructor
6437 // call.
6438 if (S.CompleteConstructorCall(Constructor, Args,
6439 Loc, ConstructorArgs,
6440 AllowExplicitConv,
6441 IsListInitialization))
6442 return ExprError();
6443
6444
6445 if (isExplicitTemporary(Entity, Kind, NumArgs)) {
6446 // An explicitly-constructed temporary, e.g., X(1, 2).
6447 if (S.DiagnoseUseOfDecl(Constructor, Loc))
6448 return ExprError();
6449
6450 TypeSourceInfo *TSInfo = Entity.getTypeSourceInfo();
6451 if (!TSInfo)
6452 TSInfo = S.Context.getTrivialTypeSourceInfo(Entity.getType(), Loc);
6453 SourceRange ParenOrBraceRange =
6454 (Kind.getKind() == InitializationKind::IK_DirectList)
6455 ? SourceRange(LBraceLoc, RBraceLoc)
6456 : Kind.getParenOrBraceRange();
6457
6458 if (auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(
6459 Step.Function.FoundDecl.getDecl())) {
6460 Constructor = S.findInheritingConstructor(Loc, Constructor, Shadow);
6461 if (S.DiagnoseUseOfDecl(Constructor, Loc))
6462 return ExprError();
6463 }
6464 S.MarkFunctionReferenced(Loc, Constructor);
6465
6466 CurInit = S.CheckForImmediateInvocation(
6467 CXXTemporaryObjectExpr::Create(
6468 S.Context, Constructor,
6469 Entity.getType().getNonLValueExprType(S.Context), TSInfo,
6470 ConstructorArgs, ParenOrBraceRange, HadMultipleCandidates,
6471 IsListInitialization, IsStdInitListInitialization,
6472 ConstructorInitRequiresZeroInit),
6473 Constructor);
6474 } else {
6475 CXXConstructExpr::ConstructionKind ConstructKind =
6476 CXXConstructExpr::CK_Complete;
6477
6478 if (Entity.getKind() == InitializedEntity::EK_Base) {
6479 ConstructKind = Entity.getBaseSpecifier()->isVirtual() ?
6480 CXXConstructExpr::CK_VirtualBase :
6481 CXXConstructExpr::CK_NonVirtualBase;
6482 } else if (Entity.getKind() == InitializedEntity::EK_Delegating) {
6483 ConstructKind = CXXConstructExpr::CK_Delegating;
6484 }
6485
6486 // Only get the parenthesis or brace range if it is a list initialization or
6487 // direct construction.
6488 SourceRange ParenOrBraceRange;
6489 if (IsListInitialization)
6490 ParenOrBraceRange = SourceRange(LBraceLoc, RBraceLoc);
6491 else if (Kind.getKind() == InitializationKind::IK_Direct)
6492 ParenOrBraceRange = Kind.getParenOrBraceRange();
6493
6494 // If the entity allows NRVO, mark the construction as elidable
6495 // unconditionally.
6496 if (Entity.allowsNRVO())
6497 CurInit = S.BuildCXXConstructExpr(Loc, Step.Type,
6498 Step.Function.FoundDecl,
6499 Constructor, /*Elidable=*/true,
6500 ConstructorArgs,
6501 HadMultipleCandidates,
6502 IsListInitialization,
6503 IsStdInitListInitialization,
6504 ConstructorInitRequiresZeroInit,
6505 ConstructKind,
6506 ParenOrBraceRange);
6507 else
6508 CurInit = S.BuildCXXConstructExpr(Loc, Step.Type,
6509 Step.Function.FoundDecl,
6510 Constructor,
6511 ConstructorArgs,
6512 HadMultipleCandidates,
6513 IsListInitialization,
6514 IsStdInitListInitialization,
6515 ConstructorInitRequiresZeroInit,
6516 ConstructKind,
6517 ParenOrBraceRange);
6518 }
6519 if (CurInit.isInvalid())
6520 return ExprError();
6521
6522 // Only check access if all of that succeeded.
6523 S.CheckConstructorAccess(Loc, Constructor, Step.Function.FoundDecl, Entity);
6524 if (S.DiagnoseUseOfDecl(Step.Function.FoundDecl, Loc))
6525 return ExprError();
6526
6527 if (const ArrayType *AT = S.Context.getAsArrayType(Entity.getType()))
6528 if (checkDestructorReference(S.Context.getBaseElementType(AT), Loc, S))
6529 return ExprError();
6530
6531 if (shouldBindAsTemporary(Entity))
6532 CurInit = S.MaybeBindToTemporary(CurInit.get());
6533
6534 return CurInit;
6535 }
6536
6537 namespace {
6538 enum LifetimeKind {
6539 /// The lifetime of a temporary bound to this entity ends at the end of the
6540 /// full-expression, and that's (probably) fine.
6541 LK_FullExpression,
6542
6543 /// The lifetime of a temporary bound to this entity is extended to the
6544 /// lifeitme of the entity itself.
6545 LK_Extended,
6546
6547 /// The lifetime of a temporary bound to this entity probably ends too soon,
6548 /// because the entity is allocated in a new-expression.
6549 LK_New,
6550
6551 /// The lifetime of a temporary bound to this entity ends too soon, because
6552 /// the entity is a return object.
6553 LK_Return,
6554
6555 /// The lifetime of a temporary bound to this entity ends too soon, because
6556 /// the entity is the result of a statement expression.
6557 LK_StmtExprResult,
6558
6559 /// This is a mem-initializer: if it would extend a temporary (other than via
6560 /// a default member initializer), the program is ill-formed.
6561 LK_MemInitializer,
6562 };
6563 using LifetimeResult =
6564 llvm::PointerIntPair<const InitializedEntity *, 3, LifetimeKind>;
6565 }
6566
6567 /// Determine the declaration which an initialized entity ultimately refers to,
6568 /// for the purpose of lifetime-extending a temporary bound to a reference in
6569 /// the initialization of \p Entity.
getEntityLifetime(const InitializedEntity * Entity,const InitializedEntity * InitField=nullptr)6570 static LifetimeResult getEntityLifetime(
6571 const InitializedEntity *Entity,
6572 const InitializedEntity *InitField = nullptr) {
6573 // C++11 [class.temporary]p5:
6574 switch (Entity->getKind()) {
6575 case InitializedEntity::EK_Variable:
6576 // The temporary [...] persists for the lifetime of the reference
6577 return {Entity, LK_Extended};
6578
6579 case InitializedEntity::EK_Member:
6580 // For subobjects, we look at the complete object.
6581 if (Entity->getParent())
6582 return getEntityLifetime(Entity->getParent(), Entity);
6583
6584 // except:
6585 // C++17 [class.base.init]p8:
6586 // A temporary expression bound to a reference member in a
6587 // mem-initializer is ill-formed.
6588 // C++17 [class.base.init]p11:
6589 // A temporary expression bound to a reference member from a
6590 // default member initializer is ill-formed.
6591 //
6592 // The context of p11 and its example suggest that it's only the use of a
6593 // default member initializer from a constructor that makes the program
6594 // ill-formed, not its mere existence, and that it can even be used by
6595 // aggregate initialization.
6596 return {Entity, Entity->isDefaultMemberInitializer() ? LK_Extended
6597 : LK_MemInitializer};
6598
6599 case InitializedEntity::EK_Binding:
6600 // Per [dcl.decomp]p3, the binding is treated as a variable of reference
6601 // type.
6602 return {Entity, LK_Extended};
6603
6604 case InitializedEntity::EK_Parameter:
6605 case InitializedEntity::EK_Parameter_CF_Audited:
6606 // -- A temporary bound to a reference parameter in a function call
6607 // persists until the completion of the full-expression containing
6608 // the call.
6609 return {nullptr, LK_FullExpression};
6610
6611 case InitializedEntity::EK_Result:
6612 // -- The lifetime of a temporary bound to the returned value in a
6613 // function return statement is not extended; the temporary is
6614 // destroyed at the end of the full-expression in the return statement.
6615 return {nullptr, LK_Return};
6616
6617 case InitializedEntity::EK_StmtExprResult:
6618 // FIXME: Should we lifetime-extend through the result of a statement
6619 // expression?
6620 return {nullptr, LK_StmtExprResult};
6621
6622 case InitializedEntity::EK_New:
6623 // -- A temporary bound to a reference in a new-initializer persists
6624 // until the completion of the full-expression containing the
6625 // new-initializer.
6626 return {nullptr, LK_New};
6627
6628 case InitializedEntity::EK_Temporary:
6629 case InitializedEntity::EK_CompoundLiteralInit:
6630 case InitializedEntity::EK_RelatedResult:
6631 // We don't yet know the storage duration of the surrounding temporary.
6632 // Assume it's got full-expression duration for now, it will patch up our
6633 // storage duration if that's not correct.
6634 return {nullptr, LK_FullExpression};
6635
6636 case InitializedEntity::EK_ArrayElement:
6637 // For subobjects, we look at the complete object.
6638 return getEntityLifetime(Entity->getParent(), InitField);
6639
6640 case InitializedEntity::EK_Base:
6641 // For subobjects, we look at the complete object.
6642 if (Entity->getParent())
6643 return getEntityLifetime(Entity->getParent(), InitField);
6644 return {InitField, LK_MemInitializer};
6645
6646 case InitializedEntity::EK_Delegating:
6647 // We can reach this case for aggregate initialization in a constructor:
6648 // struct A { int &&r; };
6649 // struct B : A { B() : A{0} {} };
6650 // In this case, use the outermost field decl as the context.
6651 return {InitField, LK_MemInitializer};
6652
6653 case InitializedEntity::EK_BlockElement:
6654 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6655 case InitializedEntity::EK_LambdaCapture:
6656 case InitializedEntity::EK_VectorElement:
6657 case InitializedEntity::EK_ComplexElement:
6658 return {nullptr, LK_FullExpression};
6659
6660 case InitializedEntity::EK_Exception:
6661 // FIXME: Can we diagnose lifetime problems with exceptions?
6662 return {nullptr, LK_FullExpression};
6663 }
6664 llvm_unreachable("unknown entity kind");
6665 }
6666
6667 namespace {
6668 enum ReferenceKind {
6669 /// Lifetime would be extended by a reference binding to a temporary.
6670 RK_ReferenceBinding,
6671 /// Lifetime would be extended by a std::initializer_list object binding to
6672 /// its backing array.
6673 RK_StdInitializerList,
6674 };
6675
6676 /// A temporary or local variable. This will be one of:
6677 /// * A MaterializeTemporaryExpr.
6678 /// * A DeclRefExpr whose declaration is a local.
6679 /// * An AddrLabelExpr.
6680 /// * A BlockExpr for a block with captures.
6681 using Local = Expr*;
6682
6683 /// Expressions we stepped over when looking for the local state. Any steps
6684 /// that would inhibit lifetime extension or take us out of subexpressions of
6685 /// the initializer are included.
6686 struct IndirectLocalPathEntry {
6687 enum EntryKind {
6688 DefaultInit,
6689 AddressOf,
6690 VarInit,
6691 LValToRVal,
6692 LifetimeBoundCall,
6693 GslReferenceInit,
6694 GslPointerInit
6695 } Kind;
6696 Expr *E;
6697 const Decl *D = nullptr;
IndirectLocalPathEntry__anon982031bb0511::IndirectLocalPathEntry6698 IndirectLocalPathEntry() {}
IndirectLocalPathEntry__anon982031bb0511::IndirectLocalPathEntry6699 IndirectLocalPathEntry(EntryKind K, Expr *E) : Kind(K), E(E) {}
IndirectLocalPathEntry__anon982031bb0511::IndirectLocalPathEntry6700 IndirectLocalPathEntry(EntryKind K, Expr *E, const Decl *D)
6701 : Kind(K), E(E), D(D) {}
6702 };
6703
6704 using IndirectLocalPath = llvm::SmallVectorImpl<IndirectLocalPathEntry>;
6705
6706 struct RevertToOldSizeRAII {
6707 IndirectLocalPath &Path;
6708 unsigned OldSize = Path.size();
RevertToOldSizeRAII__anon982031bb0511::RevertToOldSizeRAII6709 RevertToOldSizeRAII(IndirectLocalPath &Path) : Path(Path) {}
~RevertToOldSizeRAII__anon982031bb0511::RevertToOldSizeRAII6710 ~RevertToOldSizeRAII() { Path.resize(OldSize); }
6711 };
6712
6713 using LocalVisitor = llvm::function_ref<bool(IndirectLocalPath &Path, Local L,
6714 ReferenceKind RK)>;
6715 }
6716
isVarOnPath(IndirectLocalPath & Path,VarDecl * VD)6717 static bool isVarOnPath(IndirectLocalPath &Path, VarDecl *VD) {
6718 for (auto E : Path)
6719 if (E.Kind == IndirectLocalPathEntry::VarInit && E.D == VD)
6720 return true;
6721 return false;
6722 }
6723
pathContainsInit(IndirectLocalPath & Path)6724 static bool pathContainsInit(IndirectLocalPath &Path) {
6725 return llvm::any_of(Path, [=](IndirectLocalPathEntry E) {
6726 return E.Kind == IndirectLocalPathEntry::DefaultInit ||
6727 E.Kind == IndirectLocalPathEntry::VarInit;
6728 });
6729 }
6730
6731 static void visitLocalsRetainedByInitializer(IndirectLocalPath &Path,
6732 Expr *Init, LocalVisitor Visit,
6733 bool RevisitSubinits,
6734 bool EnableLifetimeWarnings);
6735
6736 static void visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
6737 Expr *Init, ReferenceKind RK,
6738 LocalVisitor Visit,
6739 bool EnableLifetimeWarnings);
6740
isRecordWithAttr(QualType Type)6741 template <typename T> static bool isRecordWithAttr(QualType Type) {
6742 if (auto *RD = Type->getAsCXXRecordDecl())
6743 return RD->hasAttr<T>();
6744 return false;
6745 }
6746
6747 // Decl::isInStdNamespace will return false for iterators in some STL
6748 // implementations due to them being defined in a namespace outside of the std
6749 // namespace.
isInStlNamespace(const Decl * D)6750 static bool isInStlNamespace(const Decl *D) {
6751 const DeclContext *DC = D->getDeclContext();
6752 if (!DC)
6753 return false;
6754 if (const auto *ND = dyn_cast<NamespaceDecl>(DC))
6755 if (const IdentifierInfo *II = ND->getIdentifier()) {
6756 StringRef Name = II->getName();
6757 if (Name.size() >= 2 && Name.front() == '_' &&
6758 (Name[1] == '_' || isUppercase(Name[1])))
6759 return true;
6760 }
6761
6762 return DC->isStdNamespace();
6763 }
6764
shouldTrackImplicitObjectArg(const CXXMethodDecl * Callee)6765 static bool shouldTrackImplicitObjectArg(const CXXMethodDecl *Callee) {
6766 if (auto *Conv = dyn_cast_or_null<CXXConversionDecl>(Callee))
6767 if (isRecordWithAttr<PointerAttr>(Conv->getConversionType()))
6768 return true;
6769 if (!isInStlNamespace(Callee->getParent()))
6770 return false;
6771 if (!isRecordWithAttr<PointerAttr>(Callee->getThisObjectType()) &&
6772 !isRecordWithAttr<OwnerAttr>(Callee->getThisObjectType()))
6773 return false;
6774 if (Callee->getReturnType()->isPointerType() ||
6775 isRecordWithAttr<PointerAttr>(Callee->getReturnType())) {
6776 if (!Callee->getIdentifier())
6777 return false;
6778 return llvm::StringSwitch<bool>(Callee->getName())
6779 .Cases("begin", "rbegin", "cbegin", "crbegin", true)
6780 .Cases("end", "rend", "cend", "crend", true)
6781 .Cases("c_str", "data", "get", true)
6782 // Map and set types.
6783 .Cases("find", "equal_range", "lower_bound", "upper_bound", true)
6784 .Default(false);
6785 } else if (Callee->getReturnType()->isReferenceType()) {
6786 if (!Callee->getIdentifier()) {
6787 auto OO = Callee->getOverloadedOperator();
6788 return OO == OverloadedOperatorKind::OO_Subscript ||
6789 OO == OverloadedOperatorKind::OO_Star;
6790 }
6791 return llvm::StringSwitch<bool>(Callee->getName())
6792 .Cases("front", "back", "at", "top", "value", true)
6793 .Default(false);
6794 }
6795 return false;
6796 }
6797
shouldTrackFirstArgument(const FunctionDecl * FD)6798 static bool shouldTrackFirstArgument(const FunctionDecl *FD) {
6799 if (!FD->getIdentifier() || FD->getNumParams() != 1)
6800 return false;
6801 const auto *RD = FD->getParamDecl(0)->getType()->getPointeeCXXRecordDecl();
6802 if (!FD->isInStdNamespace() || !RD || !RD->isInStdNamespace())
6803 return false;
6804 if (!isRecordWithAttr<PointerAttr>(QualType(RD->getTypeForDecl(), 0)) &&
6805 !isRecordWithAttr<OwnerAttr>(QualType(RD->getTypeForDecl(), 0)))
6806 return false;
6807 if (FD->getReturnType()->isPointerType() ||
6808 isRecordWithAttr<PointerAttr>(FD->getReturnType())) {
6809 return llvm::StringSwitch<bool>(FD->getName())
6810 .Cases("begin", "rbegin", "cbegin", "crbegin", true)
6811 .Cases("end", "rend", "cend", "crend", true)
6812 .Case("data", true)
6813 .Default(false);
6814 } else if (FD->getReturnType()->isReferenceType()) {
6815 return llvm::StringSwitch<bool>(FD->getName())
6816 .Cases("get", "any_cast", true)
6817 .Default(false);
6818 }
6819 return false;
6820 }
6821
handleGslAnnotatedTypes(IndirectLocalPath & Path,Expr * Call,LocalVisitor Visit)6822 static void handleGslAnnotatedTypes(IndirectLocalPath &Path, Expr *Call,
6823 LocalVisitor Visit) {
6824 auto VisitPointerArg = [&](const Decl *D, Expr *Arg, bool Value) {
6825 // We are not interested in the temporary base objects of gsl Pointers:
6826 // Temp().ptr; // Here ptr might not dangle.
6827 if (isa<MemberExpr>(Arg->IgnoreImpCasts()))
6828 return;
6829 // Once we initialized a value with a reference, it can no longer dangle.
6830 if (!Value) {
6831 for (auto It = Path.rbegin(), End = Path.rend(); It != End; ++It) {
6832 if (It->Kind == IndirectLocalPathEntry::GslReferenceInit)
6833 continue;
6834 if (It->Kind == IndirectLocalPathEntry::GslPointerInit)
6835 return;
6836 break;
6837 }
6838 }
6839 Path.push_back({Value ? IndirectLocalPathEntry::GslPointerInit
6840 : IndirectLocalPathEntry::GslReferenceInit,
6841 Arg, D});
6842 if (Arg->isGLValue())
6843 visitLocalsRetainedByReferenceBinding(Path, Arg, RK_ReferenceBinding,
6844 Visit,
6845 /*EnableLifetimeWarnings=*/true);
6846 else
6847 visitLocalsRetainedByInitializer(Path, Arg, Visit, true,
6848 /*EnableLifetimeWarnings=*/true);
6849 Path.pop_back();
6850 };
6851
6852 if (auto *MCE = dyn_cast<CXXMemberCallExpr>(Call)) {
6853 const auto *MD = cast_or_null<CXXMethodDecl>(MCE->getDirectCallee());
6854 if (MD && shouldTrackImplicitObjectArg(MD))
6855 VisitPointerArg(MD, MCE->getImplicitObjectArgument(),
6856 !MD->getReturnType()->isReferenceType());
6857 return;
6858 } else if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(Call)) {
6859 FunctionDecl *Callee = OCE->getDirectCallee();
6860 if (Callee && Callee->isCXXInstanceMember() &&
6861 shouldTrackImplicitObjectArg(cast<CXXMethodDecl>(Callee)))
6862 VisitPointerArg(Callee, OCE->getArg(0),
6863 !Callee->getReturnType()->isReferenceType());
6864 return;
6865 } else if (auto *CE = dyn_cast<CallExpr>(Call)) {
6866 FunctionDecl *Callee = CE->getDirectCallee();
6867 if (Callee && shouldTrackFirstArgument(Callee))
6868 VisitPointerArg(Callee, CE->getArg(0),
6869 !Callee->getReturnType()->isReferenceType());
6870 return;
6871 }
6872
6873 if (auto *CCE = dyn_cast<CXXConstructExpr>(Call)) {
6874 const auto *Ctor = CCE->getConstructor();
6875 const CXXRecordDecl *RD = Ctor->getParent();
6876 if (CCE->getNumArgs() > 0 && RD->hasAttr<PointerAttr>())
6877 VisitPointerArg(Ctor->getParamDecl(0), CCE->getArgs()[0], true);
6878 }
6879 }
6880
implicitObjectParamIsLifetimeBound(const FunctionDecl * FD)6881 static bool implicitObjectParamIsLifetimeBound(const FunctionDecl *FD) {
6882 const TypeSourceInfo *TSI = FD->getTypeSourceInfo();
6883 if (!TSI)
6884 return false;
6885 // Don't declare this variable in the second operand of the for-statement;
6886 // GCC miscompiles that by ending its lifetime before evaluating the
6887 // third operand. See gcc.gnu.org/PR86769.
6888 AttributedTypeLoc ATL;
6889 for (TypeLoc TL = TSI->getTypeLoc();
6890 (ATL = TL.getAsAdjusted<AttributedTypeLoc>());
6891 TL = ATL.getModifiedLoc()) {
6892 if (ATL.getAttrAs<LifetimeBoundAttr>())
6893 return true;
6894 }
6895 return false;
6896 }
6897
visitLifetimeBoundArguments(IndirectLocalPath & Path,Expr * Call,LocalVisitor Visit)6898 static void visitLifetimeBoundArguments(IndirectLocalPath &Path, Expr *Call,
6899 LocalVisitor Visit) {
6900 const FunctionDecl *Callee;
6901 ArrayRef<Expr*> Args;
6902
6903 if (auto *CE = dyn_cast<CallExpr>(Call)) {
6904 Callee = CE->getDirectCallee();
6905 Args = llvm::makeArrayRef(CE->getArgs(), CE->getNumArgs());
6906 } else {
6907 auto *CCE = cast<CXXConstructExpr>(Call);
6908 Callee = CCE->getConstructor();
6909 Args = llvm::makeArrayRef(CCE->getArgs(), CCE->getNumArgs());
6910 }
6911 if (!Callee)
6912 return;
6913
6914 Expr *ObjectArg = nullptr;
6915 if (isa<CXXOperatorCallExpr>(Call) && Callee->isCXXInstanceMember()) {
6916 ObjectArg = Args[0];
6917 Args = Args.slice(1);
6918 } else if (auto *MCE = dyn_cast<CXXMemberCallExpr>(Call)) {
6919 ObjectArg = MCE->getImplicitObjectArgument();
6920 }
6921
6922 auto VisitLifetimeBoundArg = [&](const Decl *D, Expr *Arg) {
6923 Path.push_back({IndirectLocalPathEntry::LifetimeBoundCall, Arg, D});
6924 if (Arg->isGLValue())
6925 visitLocalsRetainedByReferenceBinding(Path, Arg, RK_ReferenceBinding,
6926 Visit,
6927 /*EnableLifetimeWarnings=*/false);
6928 else
6929 visitLocalsRetainedByInitializer(Path, Arg, Visit, true,
6930 /*EnableLifetimeWarnings=*/false);
6931 Path.pop_back();
6932 };
6933
6934 if (ObjectArg && implicitObjectParamIsLifetimeBound(Callee))
6935 VisitLifetimeBoundArg(Callee, ObjectArg);
6936
6937 for (unsigned I = 0,
6938 N = std::min<unsigned>(Callee->getNumParams(), Args.size());
6939 I != N; ++I) {
6940 if (Callee->getParamDecl(I)->hasAttr<LifetimeBoundAttr>())
6941 VisitLifetimeBoundArg(Callee->getParamDecl(I), Args[I]);
6942 }
6943 }
6944
6945 /// Visit the locals that would be reachable through a reference bound to the
6946 /// glvalue expression \c Init.
visitLocalsRetainedByReferenceBinding(IndirectLocalPath & Path,Expr * Init,ReferenceKind RK,LocalVisitor Visit,bool EnableLifetimeWarnings)6947 static void visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
6948 Expr *Init, ReferenceKind RK,
6949 LocalVisitor Visit,
6950 bool EnableLifetimeWarnings) {
6951 RevertToOldSizeRAII RAII(Path);
6952
6953 // Walk past any constructs which we can lifetime-extend across.
6954 Expr *Old;
6955 do {
6956 Old = Init;
6957
6958 if (auto *FE = dyn_cast<FullExpr>(Init))
6959 Init = FE->getSubExpr();
6960
6961 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
6962 // If this is just redundant braces around an initializer, step over it.
6963 if (ILE->isTransparent())
6964 Init = ILE->getInit(0);
6965 }
6966
6967 // Step over any subobject adjustments; we may have a materialized
6968 // temporary inside them.
6969 Init = const_cast<Expr *>(Init->skipRValueSubobjectAdjustments());
6970
6971 // Per current approach for DR1376, look through casts to reference type
6972 // when performing lifetime extension.
6973 if (CastExpr *CE = dyn_cast<CastExpr>(Init))
6974 if (CE->getSubExpr()->isGLValue())
6975 Init = CE->getSubExpr();
6976
6977 // Per the current approach for DR1299, look through array element access
6978 // on array glvalues when performing lifetime extension.
6979 if (auto *ASE = dyn_cast<ArraySubscriptExpr>(Init)) {
6980 Init = ASE->getBase();
6981 auto *ICE = dyn_cast<ImplicitCastExpr>(Init);
6982 if (ICE && ICE->getCastKind() == CK_ArrayToPointerDecay)
6983 Init = ICE->getSubExpr();
6984 else
6985 // We can't lifetime extend through this but we might still find some
6986 // retained temporaries.
6987 return visitLocalsRetainedByInitializer(Path, Init, Visit, true,
6988 EnableLifetimeWarnings);
6989 }
6990
6991 // Step into CXXDefaultInitExprs so we can diagnose cases where a
6992 // constructor inherits one as an implicit mem-initializer.
6993 if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Init)) {
6994 Path.push_back(
6995 {IndirectLocalPathEntry::DefaultInit, DIE, DIE->getField()});
6996 Init = DIE->getExpr();
6997 }
6998 } while (Init != Old);
6999
7000 if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(Init)) {
7001 if (Visit(Path, Local(MTE), RK))
7002 visitLocalsRetainedByInitializer(Path, MTE->getSubExpr(), Visit, true,
7003 EnableLifetimeWarnings);
7004 }
7005
7006 if (isa<CallExpr>(Init)) {
7007 if (EnableLifetimeWarnings)
7008 handleGslAnnotatedTypes(Path, Init, Visit);
7009 return visitLifetimeBoundArguments(Path, Init, Visit);
7010 }
7011
7012 switch (Init->getStmtClass()) {
7013 case Stmt::DeclRefExprClass: {
7014 // If we find the name of a local non-reference parameter, we could have a
7015 // lifetime problem.
7016 auto *DRE = cast<DeclRefExpr>(Init);
7017 auto *VD = dyn_cast<VarDecl>(DRE->getDecl());
7018 if (VD && VD->hasLocalStorage() &&
7019 !DRE->refersToEnclosingVariableOrCapture()) {
7020 if (!VD->getType()->isReferenceType()) {
7021 Visit(Path, Local(DRE), RK);
7022 } else if (isa<ParmVarDecl>(DRE->getDecl())) {
7023 // The lifetime of a reference parameter is unknown; assume it's OK
7024 // for now.
7025 break;
7026 } else if (VD->getInit() && !isVarOnPath(Path, VD)) {
7027 Path.push_back({IndirectLocalPathEntry::VarInit, DRE, VD});
7028 visitLocalsRetainedByReferenceBinding(Path, VD->getInit(),
7029 RK_ReferenceBinding, Visit,
7030 EnableLifetimeWarnings);
7031 }
7032 }
7033 break;
7034 }
7035
7036 case Stmt::UnaryOperatorClass: {
7037 // The only unary operator that make sense to handle here
7038 // is Deref. All others don't resolve to a "name." This includes
7039 // handling all sorts of rvalues passed to a unary operator.
7040 const UnaryOperator *U = cast<UnaryOperator>(Init);
7041 if (U->getOpcode() == UO_Deref)
7042 visitLocalsRetainedByInitializer(Path, U->getSubExpr(), Visit, true,
7043 EnableLifetimeWarnings);
7044 break;
7045 }
7046
7047 case Stmt::OMPArraySectionExprClass: {
7048 visitLocalsRetainedByInitializer(Path,
7049 cast<OMPArraySectionExpr>(Init)->getBase(),
7050 Visit, true, EnableLifetimeWarnings);
7051 break;
7052 }
7053
7054 case Stmt::ConditionalOperatorClass:
7055 case Stmt::BinaryConditionalOperatorClass: {
7056 auto *C = cast<AbstractConditionalOperator>(Init);
7057 if (!C->getTrueExpr()->getType()->isVoidType())
7058 visitLocalsRetainedByReferenceBinding(Path, C->getTrueExpr(), RK, Visit,
7059 EnableLifetimeWarnings);
7060 if (!C->getFalseExpr()->getType()->isVoidType())
7061 visitLocalsRetainedByReferenceBinding(Path, C->getFalseExpr(), RK, Visit,
7062 EnableLifetimeWarnings);
7063 break;
7064 }
7065
7066 // FIXME: Visit the left-hand side of an -> or ->*.
7067
7068 default:
7069 break;
7070 }
7071 }
7072
7073 /// Visit the locals that would be reachable through an object initialized by
7074 /// the prvalue expression \c Init.
visitLocalsRetainedByInitializer(IndirectLocalPath & Path,Expr * Init,LocalVisitor Visit,bool RevisitSubinits,bool EnableLifetimeWarnings)7075 static void visitLocalsRetainedByInitializer(IndirectLocalPath &Path,
7076 Expr *Init, LocalVisitor Visit,
7077 bool RevisitSubinits,
7078 bool EnableLifetimeWarnings) {
7079 RevertToOldSizeRAII RAII(Path);
7080
7081 Expr *Old;
7082 do {
7083 Old = Init;
7084
7085 // Step into CXXDefaultInitExprs so we can diagnose cases where a
7086 // constructor inherits one as an implicit mem-initializer.
7087 if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Init)) {
7088 Path.push_back({IndirectLocalPathEntry::DefaultInit, DIE, DIE->getField()});
7089 Init = DIE->getExpr();
7090 }
7091
7092 if (auto *FE = dyn_cast<FullExpr>(Init))
7093 Init = FE->getSubExpr();
7094
7095 // Dig out the expression which constructs the extended temporary.
7096 Init = const_cast<Expr *>(Init->skipRValueSubobjectAdjustments());
7097
7098 if (CXXBindTemporaryExpr *BTE = dyn_cast<CXXBindTemporaryExpr>(Init))
7099 Init = BTE->getSubExpr();
7100
7101 Init = Init->IgnoreParens();
7102
7103 // Step over value-preserving rvalue casts.
7104 if (auto *CE = dyn_cast<CastExpr>(Init)) {
7105 switch (CE->getCastKind()) {
7106 case CK_LValueToRValue:
7107 // If we can match the lvalue to a const object, we can look at its
7108 // initializer.
7109 Path.push_back({IndirectLocalPathEntry::LValToRVal, CE});
7110 return visitLocalsRetainedByReferenceBinding(
7111 Path, Init, RK_ReferenceBinding,
7112 [&](IndirectLocalPath &Path, Local L, ReferenceKind RK) -> bool {
7113 if (auto *DRE = dyn_cast<DeclRefExpr>(L)) {
7114 auto *VD = dyn_cast<VarDecl>(DRE->getDecl());
7115 if (VD && VD->getType().isConstQualified() && VD->getInit() &&
7116 !isVarOnPath(Path, VD)) {
7117 Path.push_back({IndirectLocalPathEntry::VarInit, DRE, VD});
7118 visitLocalsRetainedByInitializer(Path, VD->getInit(), Visit, true,
7119 EnableLifetimeWarnings);
7120 }
7121 } else if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(L)) {
7122 if (MTE->getType().isConstQualified())
7123 visitLocalsRetainedByInitializer(Path, MTE->getSubExpr(), Visit,
7124 true, EnableLifetimeWarnings);
7125 }
7126 return false;
7127 }, EnableLifetimeWarnings);
7128
7129 // We assume that objects can be retained by pointers cast to integers,
7130 // but not if the integer is cast to floating-point type or to _Complex.
7131 // We assume that casts to 'bool' do not preserve enough information to
7132 // retain a local object.
7133 case CK_NoOp:
7134 case CK_BitCast:
7135 case CK_BaseToDerived:
7136 case CK_DerivedToBase:
7137 case CK_UncheckedDerivedToBase:
7138 case CK_Dynamic:
7139 case CK_ToUnion:
7140 case CK_UserDefinedConversion:
7141 case CK_ConstructorConversion:
7142 case CK_IntegralToPointer:
7143 case CK_PointerToIntegral:
7144 case CK_VectorSplat:
7145 case CK_IntegralCast:
7146 case CK_CPointerToObjCPointerCast:
7147 case CK_BlockPointerToObjCPointerCast:
7148 case CK_AnyPointerToBlockPointerCast:
7149 case CK_AddressSpaceConversion:
7150 break;
7151
7152 case CK_ArrayToPointerDecay:
7153 // Model array-to-pointer decay as taking the address of the array
7154 // lvalue.
7155 Path.push_back({IndirectLocalPathEntry::AddressOf, CE});
7156 return visitLocalsRetainedByReferenceBinding(Path, CE->getSubExpr(),
7157 RK_ReferenceBinding, Visit,
7158 EnableLifetimeWarnings);
7159
7160 default:
7161 return;
7162 }
7163
7164 Init = CE->getSubExpr();
7165 }
7166 } while (Old != Init);
7167
7168 // C++17 [dcl.init.list]p6:
7169 // initializing an initializer_list object from the array extends the
7170 // lifetime of the array exactly like binding a reference to a temporary.
7171 if (auto *ILE = dyn_cast<CXXStdInitializerListExpr>(Init))
7172 return visitLocalsRetainedByReferenceBinding(Path, ILE->getSubExpr(),
7173 RK_StdInitializerList, Visit,
7174 EnableLifetimeWarnings);
7175
7176 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
7177 // We already visited the elements of this initializer list while
7178 // performing the initialization. Don't visit them again unless we've
7179 // changed the lifetime of the initialized entity.
7180 if (!RevisitSubinits)
7181 return;
7182
7183 if (ILE->isTransparent())
7184 return visitLocalsRetainedByInitializer(Path, ILE->getInit(0), Visit,
7185 RevisitSubinits,
7186 EnableLifetimeWarnings);
7187
7188 if (ILE->getType()->isArrayType()) {
7189 for (unsigned I = 0, N = ILE->getNumInits(); I != N; ++I)
7190 visitLocalsRetainedByInitializer(Path, ILE->getInit(I), Visit,
7191 RevisitSubinits,
7192 EnableLifetimeWarnings);
7193 return;
7194 }
7195
7196 if (CXXRecordDecl *RD = ILE->getType()->getAsCXXRecordDecl()) {
7197 assert(RD->isAggregate() && "aggregate init on non-aggregate");
7198
7199 // If we lifetime-extend a braced initializer which is initializing an
7200 // aggregate, and that aggregate contains reference members which are
7201 // bound to temporaries, those temporaries are also lifetime-extended.
7202 if (RD->isUnion() && ILE->getInitializedFieldInUnion() &&
7203 ILE->getInitializedFieldInUnion()->getType()->isReferenceType())
7204 visitLocalsRetainedByReferenceBinding(Path, ILE->getInit(0),
7205 RK_ReferenceBinding, Visit,
7206 EnableLifetimeWarnings);
7207 else {
7208 unsigned Index = 0;
7209 for (; Index < RD->getNumBases() && Index < ILE->getNumInits(); ++Index)
7210 visitLocalsRetainedByInitializer(Path, ILE->getInit(Index), Visit,
7211 RevisitSubinits,
7212 EnableLifetimeWarnings);
7213 for (const auto *I : RD->fields()) {
7214 if (Index >= ILE->getNumInits())
7215 break;
7216 if (I->isUnnamedBitfield())
7217 continue;
7218 Expr *SubInit = ILE->getInit(Index);
7219 if (I->getType()->isReferenceType())
7220 visitLocalsRetainedByReferenceBinding(Path, SubInit,
7221 RK_ReferenceBinding, Visit,
7222 EnableLifetimeWarnings);
7223 else
7224 // This might be either aggregate-initialization of a member or
7225 // initialization of a std::initializer_list object. Regardless,
7226 // we should recursively lifetime-extend that initializer.
7227 visitLocalsRetainedByInitializer(Path, SubInit, Visit,
7228 RevisitSubinits,
7229 EnableLifetimeWarnings);
7230 ++Index;
7231 }
7232 }
7233 }
7234 return;
7235 }
7236
7237 // The lifetime of an init-capture is that of the closure object constructed
7238 // by a lambda-expression.
7239 if (auto *LE = dyn_cast<LambdaExpr>(Init)) {
7240 for (Expr *E : LE->capture_inits()) {
7241 if (!E)
7242 continue;
7243 if (E->isGLValue())
7244 visitLocalsRetainedByReferenceBinding(Path, E, RK_ReferenceBinding,
7245 Visit, EnableLifetimeWarnings);
7246 else
7247 visitLocalsRetainedByInitializer(Path, E, Visit, true,
7248 EnableLifetimeWarnings);
7249 }
7250 }
7251
7252 if (isa<CallExpr>(Init) || isa<CXXConstructExpr>(Init)) {
7253 if (EnableLifetimeWarnings)
7254 handleGslAnnotatedTypes(Path, Init, Visit);
7255 return visitLifetimeBoundArguments(Path, Init, Visit);
7256 }
7257
7258 switch (Init->getStmtClass()) {
7259 case Stmt::UnaryOperatorClass: {
7260 auto *UO = cast<UnaryOperator>(Init);
7261 // If the initializer is the address of a local, we could have a lifetime
7262 // problem.
7263 if (UO->getOpcode() == UO_AddrOf) {
7264 // If this is &rvalue, then it's ill-formed and we have already diagnosed
7265 // it. Don't produce a redundant warning about the lifetime of the
7266 // temporary.
7267 if (isa<MaterializeTemporaryExpr>(UO->getSubExpr()))
7268 return;
7269
7270 Path.push_back({IndirectLocalPathEntry::AddressOf, UO});
7271 visitLocalsRetainedByReferenceBinding(Path, UO->getSubExpr(),
7272 RK_ReferenceBinding, Visit,
7273 EnableLifetimeWarnings);
7274 }
7275 break;
7276 }
7277
7278 case Stmt::BinaryOperatorClass: {
7279 // Handle pointer arithmetic.
7280 auto *BO = cast<BinaryOperator>(Init);
7281 BinaryOperatorKind BOK = BO->getOpcode();
7282 if (!BO->getType()->isPointerType() || (BOK != BO_Add && BOK != BO_Sub))
7283 break;
7284
7285 if (BO->getLHS()->getType()->isPointerType())
7286 visitLocalsRetainedByInitializer(Path, BO->getLHS(), Visit, true,
7287 EnableLifetimeWarnings);
7288 else if (BO->getRHS()->getType()->isPointerType())
7289 visitLocalsRetainedByInitializer(Path, BO->getRHS(), Visit, true,
7290 EnableLifetimeWarnings);
7291 break;
7292 }
7293
7294 case Stmt::ConditionalOperatorClass:
7295 case Stmt::BinaryConditionalOperatorClass: {
7296 auto *C = cast<AbstractConditionalOperator>(Init);
7297 // In C++, we can have a throw-expression operand, which has 'void' type
7298 // and isn't interesting from a lifetime perspective.
7299 if (!C->getTrueExpr()->getType()->isVoidType())
7300 visitLocalsRetainedByInitializer(Path, C->getTrueExpr(), Visit, true,
7301 EnableLifetimeWarnings);
7302 if (!C->getFalseExpr()->getType()->isVoidType())
7303 visitLocalsRetainedByInitializer(Path, C->getFalseExpr(), Visit, true,
7304 EnableLifetimeWarnings);
7305 break;
7306 }
7307
7308 case Stmt::BlockExprClass:
7309 if (cast<BlockExpr>(Init)->getBlockDecl()->hasCaptures()) {
7310 // This is a local block, whose lifetime is that of the function.
7311 Visit(Path, Local(cast<BlockExpr>(Init)), RK_ReferenceBinding);
7312 }
7313 break;
7314
7315 case Stmt::AddrLabelExprClass:
7316 // We want to warn if the address of a label would escape the function.
7317 Visit(Path, Local(cast<AddrLabelExpr>(Init)), RK_ReferenceBinding);
7318 break;
7319
7320 default:
7321 break;
7322 }
7323 }
7324
7325 /// Determine whether this is an indirect path to a temporary that we are
7326 /// supposed to lifetime-extend along (but don't).
shouldLifetimeExtendThroughPath(const IndirectLocalPath & Path)7327 static bool shouldLifetimeExtendThroughPath(const IndirectLocalPath &Path) {
7328 for (auto Elem : Path) {
7329 if (Elem.Kind != IndirectLocalPathEntry::DefaultInit)
7330 return false;
7331 }
7332 return true;
7333 }
7334
7335 /// Find the range for the first interesting entry in the path at or after I.
nextPathEntryRange(const IndirectLocalPath & Path,unsigned I,Expr * E)7336 static SourceRange nextPathEntryRange(const IndirectLocalPath &Path, unsigned I,
7337 Expr *E) {
7338 for (unsigned N = Path.size(); I != N; ++I) {
7339 switch (Path[I].Kind) {
7340 case IndirectLocalPathEntry::AddressOf:
7341 case IndirectLocalPathEntry::LValToRVal:
7342 case IndirectLocalPathEntry::LifetimeBoundCall:
7343 case IndirectLocalPathEntry::GslReferenceInit:
7344 case IndirectLocalPathEntry::GslPointerInit:
7345 // These exist primarily to mark the path as not permitting or
7346 // supporting lifetime extension.
7347 break;
7348
7349 case IndirectLocalPathEntry::VarInit:
7350 if (cast<VarDecl>(Path[I].D)->isImplicit())
7351 return SourceRange();
7352 LLVM_FALLTHROUGH;
7353 case IndirectLocalPathEntry::DefaultInit:
7354 return Path[I].E->getSourceRange();
7355 }
7356 }
7357 return E->getSourceRange();
7358 }
7359
pathOnlyInitializesGslPointer(IndirectLocalPath & Path)7360 static bool pathOnlyInitializesGslPointer(IndirectLocalPath &Path) {
7361 for (auto It = Path.rbegin(), End = Path.rend(); It != End; ++It) {
7362 if (It->Kind == IndirectLocalPathEntry::VarInit)
7363 continue;
7364 if (It->Kind == IndirectLocalPathEntry::AddressOf)
7365 continue;
7366 return It->Kind == IndirectLocalPathEntry::GslPointerInit ||
7367 It->Kind == IndirectLocalPathEntry::GslReferenceInit;
7368 }
7369 return false;
7370 }
7371
checkInitializerLifetime(const InitializedEntity & Entity,Expr * Init)7372 void Sema::checkInitializerLifetime(const InitializedEntity &Entity,
7373 Expr *Init) {
7374 LifetimeResult LR = getEntityLifetime(&Entity);
7375 LifetimeKind LK = LR.getInt();
7376 const InitializedEntity *ExtendingEntity = LR.getPointer();
7377
7378 // If this entity doesn't have an interesting lifetime, don't bother looking
7379 // for temporaries within its initializer.
7380 if (LK == LK_FullExpression)
7381 return;
7382
7383 auto TemporaryVisitor = [&](IndirectLocalPath &Path, Local L,
7384 ReferenceKind RK) -> bool {
7385 SourceRange DiagRange = nextPathEntryRange(Path, 0, L);
7386 SourceLocation DiagLoc = DiagRange.getBegin();
7387
7388 auto *MTE = dyn_cast<MaterializeTemporaryExpr>(L);
7389
7390 bool IsGslPtrInitWithGslTempOwner = false;
7391 bool IsLocalGslOwner = false;
7392 if (pathOnlyInitializesGslPointer(Path)) {
7393 if (isa<DeclRefExpr>(L)) {
7394 // We do not want to follow the references when returning a pointer originating
7395 // from a local owner to avoid the following false positive:
7396 // int &p = *localUniquePtr;
7397 // someContainer.add(std::move(localUniquePtr));
7398 // return p;
7399 IsLocalGslOwner = isRecordWithAttr<OwnerAttr>(L->getType());
7400 if (pathContainsInit(Path) || !IsLocalGslOwner)
7401 return false;
7402 } else {
7403 IsGslPtrInitWithGslTempOwner = MTE && !MTE->getExtendingDecl() &&
7404 isRecordWithAttr<OwnerAttr>(MTE->getType());
7405 // Skipping a chain of initializing gsl::Pointer annotated objects.
7406 // We are looking only for the final source to find out if it was
7407 // a local or temporary owner or the address of a local variable/param.
7408 if (!IsGslPtrInitWithGslTempOwner)
7409 return true;
7410 }
7411 }
7412
7413 switch (LK) {
7414 case LK_FullExpression:
7415 llvm_unreachable("already handled this");
7416
7417 case LK_Extended: {
7418 if (!MTE) {
7419 // The initialized entity has lifetime beyond the full-expression,
7420 // and the local entity does too, so don't warn.
7421 //
7422 // FIXME: We should consider warning if a static / thread storage
7423 // duration variable retains an automatic storage duration local.
7424 return false;
7425 }
7426
7427 if (IsGslPtrInitWithGslTempOwner && DiagLoc.isValid()) {
7428 Diag(DiagLoc, diag::warn_dangling_lifetime_pointer) << DiagRange;
7429 return false;
7430 }
7431
7432 // Lifetime-extend the temporary.
7433 if (Path.empty()) {
7434 // Update the storage duration of the materialized temporary.
7435 // FIXME: Rebuild the expression instead of mutating it.
7436 MTE->setExtendingDecl(ExtendingEntity->getDecl(),
7437 ExtendingEntity->allocateManglingNumber());
7438 // Also visit the temporaries lifetime-extended by this initializer.
7439 return true;
7440 }
7441
7442 if (shouldLifetimeExtendThroughPath(Path)) {
7443 // We're supposed to lifetime-extend the temporary along this path (per
7444 // the resolution of DR1815), but we don't support that yet.
7445 //
7446 // FIXME: Properly handle this situation. Perhaps the easiest approach
7447 // would be to clone the initializer expression on each use that would
7448 // lifetime extend its temporaries.
7449 Diag(DiagLoc, diag::warn_unsupported_lifetime_extension)
7450 << RK << DiagRange;
7451 } else {
7452 // If the path goes through the initialization of a variable or field,
7453 // it can't possibly reach a temporary created in this full-expression.
7454 // We will have already diagnosed any problems with the initializer.
7455 if (pathContainsInit(Path))
7456 return false;
7457
7458 Diag(DiagLoc, diag::warn_dangling_variable)
7459 << RK << !Entity.getParent()
7460 << ExtendingEntity->getDecl()->isImplicit()
7461 << ExtendingEntity->getDecl() << Init->isGLValue() << DiagRange;
7462 }
7463 break;
7464 }
7465
7466 case LK_MemInitializer: {
7467 if (isa<MaterializeTemporaryExpr>(L)) {
7468 // Under C++ DR1696, if a mem-initializer (or a default member
7469 // initializer used by the absence of one) would lifetime-extend a
7470 // temporary, the program is ill-formed.
7471 if (auto *ExtendingDecl =
7472 ExtendingEntity ? ExtendingEntity->getDecl() : nullptr) {
7473 if (IsGslPtrInitWithGslTempOwner) {
7474 Diag(DiagLoc, diag::warn_dangling_lifetime_pointer_member)
7475 << ExtendingDecl << DiagRange;
7476 Diag(ExtendingDecl->getLocation(),
7477 diag::note_ref_or_ptr_member_declared_here)
7478 << true;
7479 return false;
7480 }
7481 bool IsSubobjectMember = ExtendingEntity != &Entity;
7482 Diag(DiagLoc, shouldLifetimeExtendThroughPath(Path)
7483 ? diag::err_dangling_member
7484 : diag::warn_dangling_member)
7485 << ExtendingDecl << IsSubobjectMember << RK << DiagRange;
7486 // Don't bother adding a note pointing to the field if we're inside
7487 // its default member initializer; our primary diagnostic points to
7488 // the same place in that case.
7489 if (Path.empty() ||
7490 Path.back().Kind != IndirectLocalPathEntry::DefaultInit) {
7491 Diag(ExtendingDecl->getLocation(),
7492 diag::note_lifetime_extending_member_declared_here)
7493 << RK << IsSubobjectMember;
7494 }
7495 } else {
7496 // We have a mem-initializer but no particular field within it; this
7497 // is either a base class or a delegating initializer directly
7498 // initializing the base-class from something that doesn't live long
7499 // enough.
7500 //
7501 // FIXME: Warn on this.
7502 return false;
7503 }
7504 } else {
7505 // Paths via a default initializer can only occur during error recovery
7506 // (there's no other way that a default initializer can refer to a
7507 // local). Don't produce a bogus warning on those cases.
7508 if (pathContainsInit(Path))
7509 return false;
7510
7511 // Suppress false positives for code like the one below:
7512 // Ctor(unique_ptr<T> up) : member(*up), member2(move(up)) {}
7513 if (IsLocalGslOwner && pathOnlyInitializesGslPointer(Path))
7514 return false;
7515
7516 auto *DRE = dyn_cast<DeclRefExpr>(L);
7517 auto *VD = DRE ? dyn_cast<VarDecl>(DRE->getDecl()) : nullptr;
7518 if (!VD) {
7519 // A member was initialized to a local block.
7520 // FIXME: Warn on this.
7521 return false;
7522 }
7523
7524 if (auto *Member =
7525 ExtendingEntity ? ExtendingEntity->getDecl() : nullptr) {
7526 bool IsPointer = !Member->getType()->isReferenceType();
7527 Diag(DiagLoc, IsPointer ? diag::warn_init_ptr_member_to_parameter_addr
7528 : diag::warn_bind_ref_member_to_parameter)
7529 << Member << VD << isa<ParmVarDecl>(VD) << DiagRange;
7530 Diag(Member->getLocation(),
7531 diag::note_ref_or_ptr_member_declared_here)
7532 << (unsigned)IsPointer;
7533 }
7534 }
7535 break;
7536 }
7537
7538 case LK_New:
7539 if (isa<MaterializeTemporaryExpr>(L)) {
7540 if (IsGslPtrInitWithGslTempOwner)
7541 Diag(DiagLoc, diag::warn_dangling_lifetime_pointer) << DiagRange;
7542 else
7543 Diag(DiagLoc, RK == RK_ReferenceBinding
7544 ? diag::warn_new_dangling_reference
7545 : diag::warn_new_dangling_initializer_list)
7546 << !Entity.getParent() << DiagRange;
7547 } else {
7548 // We can't determine if the allocation outlives the local declaration.
7549 return false;
7550 }
7551 break;
7552
7553 case LK_Return:
7554 case LK_StmtExprResult:
7555 if (auto *DRE = dyn_cast<DeclRefExpr>(L)) {
7556 // We can't determine if the local variable outlives the statement
7557 // expression.
7558 if (LK == LK_StmtExprResult)
7559 return false;
7560 Diag(DiagLoc, diag::warn_ret_stack_addr_ref)
7561 << Entity.getType()->isReferenceType() << DRE->getDecl()
7562 << isa<ParmVarDecl>(DRE->getDecl()) << DiagRange;
7563 } else if (isa<BlockExpr>(L)) {
7564 Diag(DiagLoc, diag::err_ret_local_block) << DiagRange;
7565 } else if (isa<AddrLabelExpr>(L)) {
7566 // Don't warn when returning a label from a statement expression.
7567 // Leaving the scope doesn't end its lifetime.
7568 if (LK == LK_StmtExprResult)
7569 return false;
7570 Diag(DiagLoc, diag::warn_ret_addr_label) << DiagRange;
7571 } else {
7572 Diag(DiagLoc, diag::warn_ret_local_temp_addr_ref)
7573 << Entity.getType()->isReferenceType() << DiagRange;
7574 }
7575 break;
7576 }
7577
7578 for (unsigned I = 0; I != Path.size(); ++I) {
7579 auto Elem = Path[I];
7580
7581 switch (Elem.Kind) {
7582 case IndirectLocalPathEntry::AddressOf:
7583 case IndirectLocalPathEntry::LValToRVal:
7584 // These exist primarily to mark the path as not permitting or
7585 // supporting lifetime extension.
7586 break;
7587
7588 case IndirectLocalPathEntry::LifetimeBoundCall:
7589 case IndirectLocalPathEntry::GslPointerInit:
7590 case IndirectLocalPathEntry::GslReferenceInit:
7591 // FIXME: Consider adding a note for these.
7592 break;
7593
7594 case IndirectLocalPathEntry::DefaultInit: {
7595 auto *FD = cast<FieldDecl>(Elem.D);
7596 Diag(FD->getLocation(), diag::note_init_with_default_member_initalizer)
7597 << FD << nextPathEntryRange(Path, I + 1, L);
7598 break;
7599 }
7600
7601 case IndirectLocalPathEntry::VarInit:
7602 const VarDecl *VD = cast<VarDecl>(Elem.D);
7603 Diag(VD->getLocation(), diag::note_local_var_initializer)
7604 << VD->getType()->isReferenceType()
7605 << VD->isImplicit() << VD->getDeclName()
7606 << nextPathEntryRange(Path, I + 1, L);
7607 break;
7608 }
7609 }
7610
7611 // We didn't lifetime-extend, so don't go any further; we don't need more
7612 // warnings or errors on inner temporaries within this one's initializer.
7613 return false;
7614 };
7615
7616 bool EnableLifetimeWarnings = !getDiagnostics().isIgnored(
7617 diag::warn_dangling_lifetime_pointer, SourceLocation());
7618 llvm::SmallVector<IndirectLocalPathEntry, 8> Path;
7619 if (Init->isGLValue())
7620 visitLocalsRetainedByReferenceBinding(Path, Init, RK_ReferenceBinding,
7621 TemporaryVisitor,
7622 EnableLifetimeWarnings);
7623 else
7624 visitLocalsRetainedByInitializer(Path, Init, TemporaryVisitor, false,
7625 EnableLifetimeWarnings);
7626 }
7627
7628 static void DiagnoseNarrowingInInitList(Sema &S,
7629 const ImplicitConversionSequence &ICS,
7630 QualType PreNarrowingType,
7631 QualType EntityType,
7632 const Expr *PostInit);
7633
7634 /// Provide warnings when std::move is used on construction.
CheckMoveOnConstruction(Sema & S,const Expr * InitExpr,bool IsReturnStmt)7635 static void CheckMoveOnConstruction(Sema &S, const Expr *InitExpr,
7636 bool IsReturnStmt) {
7637 if (!InitExpr)
7638 return;
7639
7640 if (S.inTemplateInstantiation())
7641 return;
7642
7643 QualType DestType = InitExpr->getType();
7644 if (!DestType->isRecordType())
7645 return;
7646
7647 unsigned DiagID = 0;
7648 if (IsReturnStmt) {
7649 const CXXConstructExpr *CCE =
7650 dyn_cast<CXXConstructExpr>(InitExpr->IgnoreParens());
7651 if (!CCE || CCE->getNumArgs() != 1)
7652 return;
7653
7654 if (!CCE->getConstructor()->isCopyOrMoveConstructor())
7655 return;
7656
7657 InitExpr = CCE->getArg(0)->IgnoreImpCasts();
7658 }
7659
7660 // Find the std::move call and get the argument.
7661 const CallExpr *CE = dyn_cast<CallExpr>(InitExpr->IgnoreParens());
7662 if (!CE || !CE->isCallToStdMove())
7663 return;
7664
7665 const Expr *Arg = CE->getArg(0)->IgnoreImplicit();
7666
7667 if (IsReturnStmt) {
7668 const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg->IgnoreParenImpCasts());
7669 if (!DRE || DRE->refersToEnclosingVariableOrCapture())
7670 return;
7671
7672 const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl());
7673 if (!VD || !VD->hasLocalStorage())
7674 return;
7675
7676 // __block variables are not moved implicitly.
7677 if (VD->hasAttr<BlocksAttr>())
7678 return;
7679
7680 QualType SourceType = VD->getType();
7681 if (!SourceType->isRecordType())
7682 return;
7683
7684 if (!S.Context.hasSameUnqualifiedType(DestType, SourceType)) {
7685 return;
7686 }
7687
7688 // If we're returning a function parameter, copy elision
7689 // is not possible.
7690 if (isa<ParmVarDecl>(VD))
7691 DiagID = diag::warn_redundant_move_on_return;
7692 else
7693 DiagID = diag::warn_pessimizing_move_on_return;
7694 } else {
7695 DiagID = diag::warn_pessimizing_move_on_initialization;
7696 const Expr *ArgStripped = Arg->IgnoreImplicit()->IgnoreParens();
7697 if (!ArgStripped->isRValue() || !ArgStripped->getType()->isRecordType())
7698 return;
7699 }
7700
7701 S.Diag(CE->getBeginLoc(), DiagID);
7702
7703 // Get all the locations for a fix-it. Don't emit the fix-it if any location
7704 // is within a macro.
7705 SourceLocation CallBegin = CE->getCallee()->getBeginLoc();
7706 if (CallBegin.isMacroID())
7707 return;
7708 SourceLocation RParen = CE->getRParenLoc();
7709 if (RParen.isMacroID())
7710 return;
7711 SourceLocation LParen;
7712 SourceLocation ArgLoc = Arg->getBeginLoc();
7713
7714 // Special testing for the argument location. Since the fix-it needs the
7715 // location right before the argument, the argument location can be in a
7716 // macro only if it is at the beginning of the macro.
7717 while (ArgLoc.isMacroID() &&
7718 S.getSourceManager().isAtStartOfImmediateMacroExpansion(ArgLoc)) {
7719 ArgLoc = S.getSourceManager().getImmediateExpansionRange(ArgLoc).getBegin();
7720 }
7721
7722 if (LParen.isMacroID())
7723 return;
7724
7725 LParen = ArgLoc.getLocWithOffset(-1);
7726
7727 S.Diag(CE->getBeginLoc(), diag::note_remove_move)
7728 << FixItHint::CreateRemoval(SourceRange(CallBegin, LParen))
7729 << FixItHint::CreateRemoval(SourceRange(RParen, RParen));
7730 }
7731
CheckForNullPointerDereference(Sema & S,const Expr * E)7732 static void CheckForNullPointerDereference(Sema &S, const Expr *E) {
7733 // Check to see if we are dereferencing a null pointer. If so, this is
7734 // undefined behavior, so warn about it. This only handles the pattern
7735 // "*null", which is a very syntactic check.
7736 if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E->IgnoreParenCasts()))
7737 if (UO->getOpcode() == UO_Deref &&
7738 UO->getSubExpr()->IgnoreParenCasts()->
7739 isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull)) {
7740 S.DiagRuntimeBehavior(UO->getOperatorLoc(), UO,
7741 S.PDiag(diag::warn_binding_null_to_reference)
7742 << UO->getSubExpr()->getSourceRange());
7743 }
7744 }
7745
7746 MaterializeTemporaryExpr *
CreateMaterializeTemporaryExpr(QualType T,Expr * Temporary,bool BoundToLvalueReference)7747 Sema::CreateMaterializeTemporaryExpr(QualType T, Expr *Temporary,
7748 bool BoundToLvalueReference) {
7749 auto MTE = new (Context)
7750 MaterializeTemporaryExpr(T, Temporary, BoundToLvalueReference);
7751
7752 // Order an ExprWithCleanups for lifetime marks.
7753 //
7754 // TODO: It'll be good to have a single place to check the access of the
7755 // destructor and generate ExprWithCleanups for various uses. Currently these
7756 // are done in both CreateMaterializeTemporaryExpr and MaybeBindToTemporary,
7757 // but there may be a chance to merge them.
7758 Cleanup.setExprNeedsCleanups(false);
7759 return MTE;
7760 }
7761
TemporaryMaterializationConversion(Expr * E)7762 ExprResult Sema::TemporaryMaterializationConversion(Expr *E) {
7763 // In C++98, we don't want to implicitly create an xvalue.
7764 // FIXME: This means that AST consumers need to deal with "prvalues" that
7765 // denote materialized temporaries. Maybe we should add another ValueKind
7766 // for "xvalue pretending to be a prvalue" for C++98 support.
7767 if (!E->isRValue() || !getLangOpts().CPlusPlus11)
7768 return E;
7769
7770 // C++1z [conv.rval]/1: T shall be a complete type.
7771 // FIXME: Does this ever matter (can we form a prvalue of incomplete type)?
7772 // If so, we should check for a non-abstract class type here too.
7773 QualType T = E->getType();
7774 if (RequireCompleteType(E->getExprLoc(), T, diag::err_incomplete_type))
7775 return ExprError();
7776
7777 return CreateMaterializeTemporaryExpr(E->getType(), E, false);
7778 }
7779
PerformQualificationConversion(Expr * E,QualType Ty,ExprValueKind VK,CheckedConversionKind CCK)7780 ExprResult Sema::PerformQualificationConversion(Expr *E, QualType Ty,
7781 ExprValueKind VK,
7782 CheckedConversionKind CCK) {
7783
7784 CastKind CK = CK_NoOp;
7785
7786 if (VK == VK_RValue) {
7787 auto PointeeTy = Ty->getPointeeType();
7788 auto ExprPointeeTy = E->getType()->getPointeeType();
7789 if (!PointeeTy.isNull() &&
7790 PointeeTy.getAddressSpace() != ExprPointeeTy.getAddressSpace())
7791 CK = CK_AddressSpaceConversion;
7792 } else if (Ty.getAddressSpace() != E->getType().getAddressSpace()) {
7793 CK = CK_AddressSpaceConversion;
7794 }
7795
7796 return ImpCastExprToType(E, Ty, CK, VK, /*BasePath=*/nullptr, CCK);
7797 }
7798
Perform(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Args,QualType * ResultType)7799 ExprResult InitializationSequence::Perform(Sema &S,
7800 const InitializedEntity &Entity,
7801 const InitializationKind &Kind,
7802 MultiExprArg Args,
7803 QualType *ResultType) {
7804 if (Failed()) {
7805 Diagnose(S, Entity, Kind, Args);
7806 return ExprError();
7807 }
7808 if (!ZeroInitializationFixit.empty()) {
7809 unsigned DiagID = diag::err_default_init_const;
7810 if (Decl *D = Entity.getDecl())
7811 if (S.getLangOpts().MSVCCompat && D->hasAttr<SelectAnyAttr>())
7812 DiagID = diag::ext_default_init_const;
7813
7814 // The initialization would have succeeded with this fixit. Since the fixit
7815 // is on the error, we need to build a valid AST in this case, so this isn't
7816 // handled in the Failed() branch above.
7817 QualType DestType = Entity.getType();
7818 S.Diag(Kind.getLocation(), DiagID)
7819 << DestType << (bool)DestType->getAs<RecordType>()
7820 << FixItHint::CreateInsertion(ZeroInitializationFixitLoc,
7821 ZeroInitializationFixit);
7822 }
7823
7824 if (getKind() == DependentSequence) {
7825 // If the declaration is a non-dependent, incomplete array type
7826 // that has an initializer, then its type will be completed once
7827 // the initializer is instantiated.
7828 if (ResultType && !Entity.getType()->isDependentType() &&
7829 Args.size() == 1) {
7830 QualType DeclType = Entity.getType();
7831 if (const IncompleteArrayType *ArrayT
7832 = S.Context.getAsIncompleteArrayType(DeclType)) {
7833 // FIXME: We don't currently have the ability to accurately
7834 // compute the length of an initializer list without
7835 // performing full type-checking of the initializer list
7836 // (since we have to determine where braces are implicitly
7837 // introduced and such). So, we fall back to making the array
7838 // type a dependently-sized array type with no specified
7839 // bound.
7840 if (isa<InitListExpr>((Expr *)Args[0])) {
7841 SourceRange Brackets;
7842
7843 // Scavange the location of the brackets from the entity, if we can.
7844 if (auto *DD = dyn_cast_or_null<DeclaratorDecl>(Entity.getDecl())) {
7845 if (TypeSourceInfo *TInfo = DD->getTypeSourceInfo()) {
7846 TypeLoc TL = TInfo->getTypeLoc();
7847 if (IncompleteArrayTypeLoc ArrayLoc =
7848 TL.getAs<IncompleteArrayTypeLoc>())
7849 Brackets = ArrayLoc.getBracketsRange();
7850 }
7851 }
7852
7853 *ResultType
7854 = S.Context.getDependentSizedArrayType(ArrayT->getElementType(),
7855 /*NumElts=*/nullptr,
7856 ArrayT->getSizeModifier(),
7857 ArrayT->getIndexTypeCVRQualifiers(),
7858 Brackets);
7859 }
7860
7861 }
7862 }
7863 if (Kind.getKind() == InitializationKind::IK_Direct &&
7864 !Kind.isExplicitCast()) {
7865 // Rebuild the ParenListExpr.
7866 SourceRange ParenRange = Kind.getParenOrBraceRange();
7867 return S.ActOnParenListExpr(ParenRange.getBegin(), ParenRange.getEnd(),
7868 Args);
7869 }
7870 assert(Kind.getKind() == InitializationKind::IK_Copy ||
7871 Kind.isExplicitCast() ||
7872 Kind.getKind() == InitializationKind::IK_DirectList);
7873 return ExprResult(Args[0]);
7874 }
7875
7876 // No steps means no initialization.
7877 if (Steps.empty())
7878 return ExprResult((Expr *)nullptr);
7879
7880 if (S.getLangOpts().CPlusPlus11 && Entity.getType()->isReferenceType() &&
7881 Args.size() == 1 && isa<InitListExpr>(Args[0]) &&
7882 !Entity.isParameterKind()) {
7883 // Produce a C++98 compatibility warning if we are initializing a reference
7884 // from an initializer list. For parameters, we produce a better warning
7885 // elsewhere.
7886 Expr *Init = Args[0];
7887 S.Diag(Init->getBeginLoc(), diag::warn_cxx98_compat_reference_list_init)
7888 << Init->getSourceRange();
7889 }
7890
7891 // OpenCL v2.0 s6.13.11.1. atomic variables can be initialized in global scope
7892 QualType ETy = Entity.getType();
7893 bool HasGlobalAS = ETy.hasAddressSpace() &&
7894 ETy.getAddressSpace() == LangAS::opencl_global;
7895
7896 if (S.getLangOpts().OpenCLVersion >= 200 &&
7897 ETy->isAtomicType() && !HasGlobalAS &&
7898 Entity.getKind() == InitializedEntity::EK_Variable && Args.size() > 0) {
7899 S.Diag(Args[0]->getBeginLoc(), diag::err_opencl_atomic_init)
7900 << 1
7901 << SourceRange(Entity.getDecl()->getBeginLoc(), Args[0]->getEndLoc());
7902 return ExprError();
7903 }
7904
7905 QualType DestType = Entity.getType().getNonReferenceType();
7906 // FIXME: Ugly hack around the fact that Entity.getType() is not
7907 // the same as Entity.getDecl()->getType() in cases involving type merging,
7908 // and we want latter when it makes sense.
7909 if (ResultType)
7910 *ResultType = Entity.getDecl() ? Entity.getDecl()->getType() :
7911 Entity.getType();
7912
7913 ExprResult CurInit((Expr *)nullptr);
7914 SmallVector<Expr*, 4> ArrayLoopCommonExprs;
7915
7916 // For initialization steps that start with a single initializer,
7917 // grab the only argument out the Args and place it into the "current"
7918 // initializer.
7919 switch (Steps.front().Kind) {
7920 case SK_ResolveAddressOfOverloadedFunction:
7921 case SK_CastDerivedToBaseRValue:
7922 case SK_CastDerivedToBaseXValue:
7923 case SK_CastDerivedToBaseLValue:
7924 case SK_BindReference:
7925 case SK_BindReferenceToTemporary:
7926 case SK_FinalCopy:
7927 case SK_ExtraneousCopyToTemporary:
7928 case SK_UserConversion:
7929 case SK_QualificationConversionLValue:
7930 case SK_QualificationConversionXValue:
7931 case SK_QualificationConversionRValue:
7932 case SK_AtomicConversion:
7933 case SK_ConversionSequence:
7934 case SK_ConversionSequenceNoNarrowing:
7935 case SK_ListInitialization:
7936 case SK_UnwrapInitList:
7937 case SK_RewrapInitList:
7938 case SK_CAssignment:
7939 case SK_StringInit:
7940 case SK_ObjCObjectConversion:
7941 case SK_ArrayLoopIndex:
7942 case SK_ArrayLoopInit:
7943 case SK_ArrayInit:
7944 case SK_GNUArrayInit:
7945 case SK_ParenthesizedArrayInit:
7946 case SK_PassByIndirectCopyRestore:
7947 case SK_PassByIndirectRestore:
7948 case SK_ProduceObjCObject:
7949 case SK_StdInitializerList:
7950 case SK_OCLSamplerInit:
7951 case SK_OCLZeroOpaqueType: {
7952 assert(Args.size() == 1);
7953 CurInit = Args[0];
7954 if (!CurInit.get()) return ExprError();
7955 break;
7956 }
7957
7958 case SK_ConstructorInitialization:
7959 case SK_ConstructorInitializationFromList:
7960 case SK_StdInitializerListConstructorCall:
7961 case SK_ZeroInitialization:
7962 break;
7963 }
7964
7965 // Promote from an unevaluated context to an unevaluated list context in
7966 // C++11 list-initialization; we need to instantiate entities usable in
7967 // constant expressions here in order to perform narrowing checks =(
7968 EnterExpressionEvaluationContext Evaluated(
7969 S, EnterExpressionEvaluationContext::InitList,
7970 CurInit.get() && isa<InitListExpr>(CurInit.get()));
7971
7972 // C++ [class.abstract]p2:
7973 // no objects of an abstract class can be created except as subobjects
7974 // of a class derived from it
7975 auto checkAbstractType = [&](QualType T) -> bool {
7976 if (Entity.getKind() == InitializedEntity::EK_Base ||
7977 Entity.getKind() == InitializedEntity::EK_Delegating)
7978 return false;
7979 return S.RequireNonAbstractType(Kind.getLocation(), T,
7980 diag::err_allocation_of_abstract_type);
7981 };
7982
7983 // Walk through the computed steps for the initialization sequence,
7984 // performing the specified conversions along the way.
7985 bool ConstructorInitRequiresZeroInit = false;
7986 for (step_iterator Step = step_begin(), StepEnd = step_end();
7987 Step != StepEnd; ++Step) {
7988 if (CurInit.isInvalid())
7989 return ExprError();
7990
7991 QualType SourceType = CurInit.get() ? CurInit.get()->getType() : QualType();
7992
7993 switch (Step->Kind) {
7994 case SK_ResolveAddressOfOverloadedFunction:
7995 // Overload resolution determined which function invoke; update the
7996 // initializer to reflect that choice.
7997 S.CheckAddressOfMemberAccess(CurInit.get(), Step->Function.FoundDecl);
7998 if (S.DiagnoseUseOfDecl(Step->Function.FoundDecl, Kind.getLocation()))
7999 return ExprError();
8000 CurInit = S.FixOverloadedFunctionReference(CurInit,
8001 Step->Function.FoundDecl,
8002 Step->Function.Function);
8003 break;
8004
8005 case SK_CastDerivedToBaseRValue:
8006 case SK_CastDerivedToBaseXValue:
8007 case SK_CastDerivedToBaseLValue: {
8008 // We have a derived-to-base cast that produces either an rvalue or an
8009 // lvalue. Perform that cast.
8010
8011 CXXCastPath BasePath;
8012
8013 // Casts to inaccessible base classes are allowed with C-style casts.
8014 bool IgnoreBaseAccess = Kind.isCStyleOrFunctionalCast();
8015 if (S.CheckDerivedToBaseConversion(
8016 SourceType, Step->Type, CurInit.get()->getBeginLoc(),
8017 CurInit.get()->getSourceRange(), &BasePath, IgnoreBaseAccess))
8018 return ExprError();
8019
8020 ExprValueKind VK =
8021 Step->Kind == SK_CastDerivedToBaseLValue ?
8022 VK_LValue :
8023 (Step->Kind == SK_CastDerivedToBaseXValue ?
8024 VK_XValue :
8025 VK_RValue);
8026 CurInit =
8027 ImplicitCastExpr::Create(S.Context, Step->Type, CK_DerivedToBase,
8028 CurInit.get(), &BasePath, VK);
8029 break;
8030 }
8031
8032 case SK_BindReference:
8033 // Reference binding does not have any corresponding ASTs.
8034
8035 // Check exception specifications
8036 if (S.CheckExceptionSpecCompatibility(CurInit.get(), DestType))
8037 return ExprError();
8038
8039 // We don't check for e.g. function pointers here, since address
8040 // availability checks should only occur when the function first decays
8041 // into a pointer or reference.
8042 if (CurInit.get()->getType()->isFunctionProtoType()) {
8043 if (auto *DRE = dyn_cast<DeclRefExpr>(CurInit.get()->IgnoreParens())) {
8044 if (auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl())) {
8045 if (!S.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true,
8046 DRE->getBeginLoc()))
8047 return ExprError();
8048 }
8049 }
8050 }
8051
8052 CheckForNullPointerDereference(S, CurInit.get());
8053 break;
8054
8055 case SK_BindReferenceToTemporary: {
8056 // Make sure the "temporary" is actually an rvalue.
8057 assert(CurInit.get()->isRValue() && "not a temporary");
8058
8059 // Check exception specifications
8060 if (S.CheckExceptionSpecCompatibility(CurInit.get(), DestType))
8061 return ExprError();
8062
8063 // Materialize the temporary into memory.
8064 MaterializeTemporaryExpr *MTE = S.CreateMaterializeTemporaryExpr(
8065 Step->Type, CurInit.get(), Entity.getType()->isLValueReferenceType());
8066 CurInit = MTE;
8067
8068 // If we're extending this temporary to automatic storage duration -- we
8069 // need to register its cleanup during the full-expression's cleanups.
8070 if (MTE->getStorageDuration() == SD_Automatic &&
8071 MTE->getType().isDestructedType())
8072 S.Cleanup.setExprNeedsCleanups(true);
8073 break;
8074 }
8075
8076 case SK_FinalCopy:
8077 if (checkAbstractType(Step->Type))
8078 return ExprError();
8079
8080 // If the overall initialization is initializing a temporary, we already
8081 // bound our argument if it was necessary to do so. If not (if we're
8082 // ultimately initializing a non-temporary), our argument needs to be
8083 // bound since it's initializing a function parameter.
8084 // FIXME: This is a mess. Rationalize temporary destruction.
8085 if (!shouldBindAsTemporary(Entity))
8086 CurInit = S.MaybeBindToTemporary(CurInit.get());
8087 CurInit = CopyObject(S, Step->Type, Entity, CurInit,
8088 /*IsExtraneousCopy=*/false);
8089 break;
8090
8091 case SK_ExtraneousCopyToTemporary:
8092 CurInit = CopyObject(S, Step->Type, Entity, CurInit,
8093 /*IsExtraneousCopy=*/true);
8094 break;
8095
8096 case SK_UserConversion: {
8097 // We have a user-defined conversion that invokes either a constructor
8098 // or a conversion function.
8099 CastKind CastKind;
8100 FunctionDecl *Fn = Step->Function.Function;
8101 DeclAccessPair FoundFn = Step->Function.FoundDecl;
8102 bool HadMultipleCandidates = Step->Function.HadMultipleCandidates;
8103 bool CreatedObject = false;
8104 if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Fn)) {
8105 // Build a call to the selected constructor.
8106 SmallVector<Expr*, 8> ConstructorArgs;
8107 SourceLocation Loc = CurInit.get()->getBeginLoc();
8108
8109 // Determine the arguments required to actually perform the constructor
8110 // call.
8111 Expr *Arg = CurInit.get();
8112 if (S.CompleteConstructorCall(Constructor,
8113 MultiExprArg(&Arg, 1),
8114 Loc, ConstructorArgs))
8115 return ExprError();
8116
8117 // Build an expression that constructs a temporary.
8118 CurInit = S.BuildCXXConstructExpr(Loc, Step->Type,
8119 FoundFn, Constructor,
8120 ConstructorArgs,
8121 HadMultipleCandidates,
8122 /*ListInit*/ false,
8123 /*StdInitListInit*/ false,
8124 /*ZeroInit*/ false,
8125 CXXConstructExpr::CK_Complete,
8126 SourceRange());
8127 if (CurInit.isInvalid())
8128 return ExprError();
8129
8130 S.CheckConstructorAccess(Kind.getLocation(), Constructor, FoundFn,
8131 Entity);
8132 if (S.DiagnoseUseOfDecl(FoundFn, Kind.getLocation()))
8133 return ExprError();
8134
8135 CastKind = CK_ConstructorConversion;
8136 CreatedObject = true;
8137 } else {
8138 // Build a call to the conversion function.
8139 CXXConversionDecl *Conversion = cast<CXXConversionDecl>(Fn);
8140 S.CheckMemberOperatorAccess(Kind.getLocation(), CurInit.get(), nullptr,
8141 FoundFn);
8142 if (S.DiagnoseUseOfDecl(FoundFn, Kind.getLocation()))
8143 return ExprError();
8144
8145 CurInit = S.BuildCXXMemberCallExpr(CurInit.get(), FoundFn, Conversion,
8146 HadMultipleCandidates);
8147 if (CurInit.isInvalid())
8148 return ExprError();
8149
8150 CastKind = CK_UserDefinedConversion;
8151 CreatedObject = Conversion->getReturnType()->isRecordType();
8152 }
8153
8154 if (CreatedObject && checkAbstractType(CurInit.get()->getType()))
8155 return ExprError();
8156
8157 CurInit = ImplicitCastExpr::Create(S.Context, CurInit.get()->getType(),
8158 CastKind, CurInit.get(), nullptr,
8159 CurInit.get()->getValueKind());
8160
8161 if (shouldBindAsTemporary(Entity))
8162 // The overall entity is temporary, so this expression should be
8163 // destroyed at the end of its full-expression.
8164 CurInit = S.MaybeBindToTemporary(CurInit.getAs<Expr>());
8165 else if (CreatedObject && shouldDestroyEntity(Entity)) {
8166 // The object outlasts the full-expression, but we need to prepare for
8167 // a destructor being run on it.
8168 // FIXME: It makes no sense to do this here. This should happen
8169 // regardless of how we initialized the entity.
8170 QualType T = CurInit.get()->getType();
8171 if (const RecordType *Record = T->getAs<RecordType>()) {
8172 CXXDestructorDecl *Destructor
8173 = S.LookupDestructor(cast<CXXRecordDecl>(Record->getDecl()));
8174 S.CheckDestructorAccess(CurInit.get()->getBeginLoc(), Destructor,
8175 S.PDiag(diag::err_access_dtor_temp) << T);
8176 S.MarkFunctionReferenced(CurInit.get()->getBeginLoc(), Destructor);
8177 if (S.DiagnoseUseOfDecl(Destructor, CurInit.get()->getBeginLoc()))
8178 return ExprError();
8179 }
8180 }
8181 break;
8182 }
8183
8184 case SK_QualificationConversionLValue:
8185 case SK_QualificationConversionXValue:
8186 case SK_QualificationConversionRValue: {
8187 // Perform a qualification conversion; these can never go wrong.
8188 ExprValueKind VK =
8189 Step->Kind == SK_QualificationConversionLValue
8190 ? VK_LValue
8191 : (Step->Kind == SK_QualificationConversionXValue ? VK_XValue
8192 : VK_RValue);
8193 CurInit = S.PerformQualificationConversion(CurInit.get(), Step->Type, VK);
8194 break;
8195 }
8196
8197 case SK_AtomicConversion: {
8198 assert(CurInit.get()->isRValue() && "cannot convert glvalue to atomic");
8199 CurInit = S.ImpCastExprToType(CurInit.get(), Step->Type,
8200 CK_NonAtomicToAtomic, VK_RValue);
8201 break;
8202 }
8203
8204 case SK_ConversionSequence:
8205 case SK_ConversionSequenceNoNarrowing: {
8206 if (const auto *FromPtrType =
8207 CurInit.get()->getType()->getAs<PointerType>()) {
8208 if (const auto *ToPtrType = Step->Type->getAs<PointerType>()) {
8209 if (FromPtrType->getPointeeType()->hasAttr(attr::NoDeref) &&
8210 !ToPtrType->getPointeeType()->hasAttr(attr::NoDeref)) {
8211 // Do not check static casts here because they are checked earlier
8212 // in Sema::ActOnCXXNamedCast()
8213 if (!Kind.isStaticCast()) {
8214 S.Diag(CurInit.get()->getExprLoc(),
8215 diag::warn_noderef_to_dereferenceable_pointer)
8216 << CurInit.get()->getSourceRange();
8217 }
8218 }
8219 }
8220 }
8221
8222 Sema::CheckedConversionKind CCK
8223 = Kind.isCStyleCast()? Sema::CCK_CStyleCast
8224 : Kind.isFunctionalCast()? Sema::CCK_FunctionalCast
8225 : Kind.isExplicitCast()? Sema::CCK_OtherCast
8226 : Sema::CCK_ImplicitConversion;
8227 ExprResult CurInitExprRes =
8228 S.PerformImplicitConversion(CurInit.get(), Step->Type, *Step->ICS,
8229 getAssignmentAction(Entity), CCK);
8230 if (CurInitExprRes.isInvalid())
8231 return ExprError();
8232
8233 S.DiscardMisalignedMemberAddress(Step->Type.getTypePtr(), CurInit.get());
8234
8235 CurInit = CurInitExprRes;
8236
8237 if (Step->Kind == SK_ConversionSequenceNoNarrowing &&
8238 S.getLangOpts().CPlusPlus)
8239 DiagnoseNarrowingInInitList(S, *Step->ICS, SourceType, Entity.getType(),
8240 CurInit.get());
8241
8242 break;
8243 }
8244
8245 case SK_ListInitialization: {
8246 if (checkAbstractType(Step->Type))
8247 return ExprError();
8248
8249 InitListExpr *InitList = cast<InitListExpr>(CurInit.get());
8250 // If we're not initializing the top-level entity, we need to create an
8251 // InitializeTemporary entity for our target type.
8252 QualType Ty = Step->Type;
8253 bool IsTemporary = !S.Context.hasSameType(Entity.getType(), Ty);
8254 InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(Ty);
8255 InitializedEntity InitEntity = IsTemporary ? TempEntity : Entity;
8256 InitListChecker PerformInitList(S, InitEntity,
8257 InitList, Ty, /*VerifyOnly=*/false,
8258 /*TreatUnavailableAsInvalid=*/false);
8259 if (PerformInitList.HadError())
8260 return ExprError();
8261
8262 // Hack: We must update *ResultType if available in order to set the
8263 // bounds of arrays, e.g. in 'int ar[] = {1, 2, 3};'.
8264 // Worst case: 'const int (&arref)[] = {1, 2, 3};'.
8265 if (ResultType &&
8266 ResultType->getNonReferenceType()->isIncompleteArrayType()) {
8267 if ((*ResultType)->isRValueReferenceType())
8268 Ty = S.Context.getRValueReferenceType(Ty);
8269 else if ((*ResultType)->isLValueReferenceType())
8270 Ty = S.Context.getLValueReferenceType(Ty,
8271 (*ResultType)->castAs<LValueReferenceType>()->isSpelledAsLValue());
8272 *ResultType = Ty;
8273 }
8274
8275 InitListExpr *StructuredInitList =
8276 PerformInitList.getFullyStructuredList();
8277 CurInit.get();
8278 CurInit = shouldBindAsTemporary(InitEntity)
8279 ? S.MaybeBindToTemporary(StructuredInitList)
8280 : StructuredInitList;
8281 break;
8282 }
8283
8284 case SK_ConstructorInitializationFromList: {
8285 if (checkAbstractType(Step->Type))
8286 return ExprError();
8287
8288 // When an initializer list is passed for a parameter of type "reference
8289 // to object", we don't get an EK_Temporary entity, but instead an
8290 // EK_Parameter entity with reference type.
8291 // FIXME: This is a hack. What we really should do is create a user
8292 // conversion step for this case, but this makes it considerably more
8293 // complicated. For now, this will do.
8294 InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(
8295 Entity.getType().getNonReferenceType());
8296 bool UseTemporary = Entity.getType()->isReferenceType();
8297 assert(Args.size() == 1 && "expected a single argument for list init");
8298 InitListExpr *InitList = cast<InitListExpr>(Args[0]);
8299 S.Diag(InitList->getExprLoc(), diag::warn_cxx98_compat_ctor_list_init)
8300 << InitList->getSourceRange();
8301 MultiExprArg Arg(InitList->getInits(), InitList->getNumInits());
8302 CurInit = PerformConstructorInitialization(S, UseTemporary ? TempEntity :
8303 Entity,
8304 Kind, Arg, *Step,
8305 ConstructorInitRequiresZeroInit,
8306 /*IsListInitialization*/true,
8307 /*IsStdInitListInit*/false,
8308 InitList->getLBraceLoc(),
8309 InitList->getRBraceLoc());
8310 break;
8311 }
8312
8313 case SK_UnwrapInitList:
8314 CurInit = cast<InitListExpr>(CurInit.get())->getInit(0);
8315 break;
8316
8317 case SK_RewrapInitList: {
8318 Expr *E = CurInit.get();
8319 InitListExpr *Syntactic = Step->WrappingSyntacticList;
8320 InitListExpr *ILE = new (S.Context) InitListExpr(S.Context,
8321 Syntactic->getLBraceLoc(), E, Syntactic->getRBraceLoc());
8322 ILE->setSyntacticForm(Syntactic);
8323 ILE->setType(E->getType());
8324 ILE->setValueKind(E->getValueKind());
8325 CurInit = ILE;
8326 break;
8327 }
8328
8329 case SK_ConstructorInitialization:
8330 case SK_StdInitializerListConstructorCall: {
8331 if (checkAbstractType(Step->Type))
8332 return ExprError();
8333
8334 // When an initializer list is passed for a parameter of type "reference
8335 // to object", we don't get an EK_Temporary entity, but instead an
8336 // EK_Parameter entity with reference type.
8337 // FIXME: This is a hack. What we really should do is create a user
8338 // conversion step for this case, but this makes it considerably more
8339 // complicated. For now, this will do.
8340 InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(
8341 Entity.getType().getNonReferenceType());
8342 bool UseTemporary = Entity.getType()->isReferenceType();
8343 bool IsStdInitListInit =
8344 Step->Kind == SK_StdInitializerListConstructorCall;
8345 Expr *Source = CurInit.get();
8346 SourceRange Range = Kind.hasParenOrBraceRange()
8347 ? Kind.getParenOrBraceRange()
8348 : SourceRange();
8349 CurInit = PerformConstructorInitialization(
8350 S, UseTemporary ? TempEntity : Entity, Kind,
8351 Source ? MultiExprArg(Source) : Args, *Step,
8352 ConstructorInitRequiresZeroInit,
8353 /*IsListInitialization*/ IsStdInitListInit,
8354 /*IsStdInitListInitialization*/ IsStdInitListInit,
8355 /*LBraceLoc*/ Range.getBegin(),
8356 /*RBraceLoc*/ Range.getEnd());
8357 break;
8358 }
8359
8360 case SK_ZeroInitialization: {
8361 step_iterator NextStep = Step;
8362 ++NextStep;
8363 if (NextStep != StepEnd &&
8364 (NextStep->Kind == SK_ConstructorInitialization ||
8365 NextStep->Kind == SK_ConstructorInitializationFromList)) {
8366 // The need for zero-initialization is recorded directly into
8367 // the call to the object's constructor within the next step.
8368 ConstructorInitRequiresZeroInit = true;
8369 } else if (Kind.getKind() == InitializationKind::IK_Value &&
8370 S.getLangOpts().CPlusPlus &&
8371 !Kind.isImplicitValueInit()) {
8372 TypeSourceInfo *TSInfo = Entity.getTypeSourceInfo();
8373 if (!TSInfo)
8374 TSInfo = S.Context.getTrivialTypeSourceInfo(Step->Type,
8375 Kind.getRange().getBegin());
8376
8377 CurInit = new (S.Context) CXXScalarValueInitExpr(
8378 Entity.getType().getNonLValueExprType(S.Context), TSInfo,
8379 Kind.getRange().getEnd());
8380 } else {
8381 CurInit = new (S.Context) ImplicitValueInitExpr(Step->Type);
8382 }
8383 break;
8384 }
8385
8386 case SK_CAssignment: {
8387 QualType SourceType = CurInit.get()->getType();
8388
8389 // Save off the initial CurInit in case we need to emit a diagnostic
8390 ExprResult InitialCurInit = CurInit;
8391 ExprResult Result = CurInit;
8392 Sema::AssignConvertType ConvTy =
8393 S.CheckSingleAssignmentConstraints(Step->Type, Result, true,
8394 Entity.getKind() == InitializedEntity::EK_Parameter_CF_Audited);
8395 if (Result.isInvalid())
8396 return ExprError();
8397 CurInit = Result;
8398
8399 // If this is a call, allow conversion to a transparent union.
8400 ExprResult CurInitExprRes = CurInit;
8401 if (ConvTy != Sema::Compatible &&
8402 Entity.isParameterKind() &&
8403 S.CheckTransparentUnionArgumentConstraints(Step->Type, CurInitExprRes)
8404 == Sema::Compatible)
8405 ConvTy = Sema::Compatible;
8406 if (CurInitExprRes.isInvalid())
8407 return ExprError();
8408 CurInit = CurInitExprRes;
8409
8410 bool Complained;
8411 if (S.DiagnoseAssignmentResult(ConvTy, Kind.getLocation(),
8412 Step->Type, SourceType,
8413 InitialCurInit.get(),
8414 getAssignmentAction(Entity, true),
8415 &Complained)) {
8416 PrintInitLocationNote(S, Entity);
8417 return ExprError();
8418 } else if (Complained)
8419 PrintInitLocationNote(S, Entity);
8420 break;
8421 }
8422
8423 case SK_StringInit: {
8424 QualType Ty = Step->Type;
8425 CheckStringInit(CurInit.get(), ResultType ? *ResultType : Ty,
8426 S.Context.getAsArrayType(Ty), S);
8427 break;
8428 }
8429
8430 case SK_ObjCObjectConversion:
8431 CurInit = S.ImpCastExprToType(CurInit.get(), Step->Type,
8432 CK_ObjCObjectLValueCast,
8433 CurInit.get()->getValueKind());
8434 break;
8435
8436 case SK_ArrayLoopIndex: {
8437 Expr *Cur = CurInit.get();
8438 Expr *BaseExpr = new (S.Context)
8439 OpaqueValueExpr(Cur->getExprLoc(), Cur->getType(),
8440 Cur->getValueKind(), Cur->getObjectKind(), Cur);
8441 Expr *IndexExpr =
8442 new (S.Context) ArrayInitIndexExpr(S.Context.getSizeType());
8443 CurInit = S.CreateBuiltinArraySubscriptExpr(
8444 BaseExpr, Kind.getLocation(), IndexExpr, Kind.getLocation());
8445 ArrayLoopCommonExprs.push_back(BaseExpr);
8446 break;
8447 }
8448
8449 case SK_ArrayLoopInit: {
8450 assert(!ArrayLoopCommonExprs.empty() &&
8451 "mismatched SK_ArrayLoopIndex and SK_ArrayLoopInit");
8452 Expr *Common = ArrayLoopCommonExprs.pop_back_val();
8453 CurInit = new (S.Context) ArrayInitLoopExpr(Step->Type, Common,
8454 CurInit.get());
8455 break;
8456 }
8457
8458 case SK_GNUArrayInit:
8459 // Okay: we checked everything before creating this step. Note that
8460 // this is a GNU extension.
8461 S.Diag(Kind.getLocation(), diag::ext_array_init_copy)
8462 << Step->Type << CurInit.get()->getType()
8463 << CurInit.get()->getSourceRange();
8464 updateGNUCompoundLiteralRValue(CurInit.get());
8465 LLVM_FALLTHROUGH;
8466 case SK_ArrayInit:
8467 // If the destination type is an incomplete array type, update the
8468 // type accordingly.
8469 if (ResultType) {
8470 if (const IncompleteArrayType *IncompleteDest
8471 = S.Context.getAsIncompleteArrayType(Step->Type)) {
8472 if (const ConstantArrayType *ConstantSource
8473 = S.Context.getAsConstantArrayType(CurInit.get()->getType())) {
8474 *ResultType = S.Context.getConstantArrayType(
8475 IncompleteDest->getElementType(),
8476 ConstantSource->getSize(),
8477 ConstantSource->getSizeExpr(),
8478 ArrayType::Normal, 0);
8479 }
8480 }
8481 }
8482 break;
8483
8484 case SK_ParenthesizedArrayInit:
8485 // Okay: we checked everything before creating this step. Note that
8486 // this is a GNU extension.
8487 S.Diag(Kind.getLocation(), diag::ext_array_init_parens)
8488 << CurInit.get()->getSourceRange();
8489 break;
8490
8491 case SK_PassByIndirectCopyRestore:
8492 case SK_PassByIndirectRestore:
8493 checkIndirectCopyRestoreSource(S, CurInit.get());
8494 CurInit = new (S.Context) ObjCIndirectCopyRestoreExpr(
8495 CurInit.get(), Step->Type,
8496 Step->Kind == SK_PassByIndirectCopyRestore);
8497 break;
8498
8499 case SK_ProduceObjCObject:
8500 CurInit =
8501 ImplicitCastExpr::Create(S.Context, Step->Type, CK_ARCProduceObject,
8502 CurInit.get(), nullptr, VK_RValue);
8503 break;
8504
8505 case SK_StdInitializerList: {
8506 S.Diag(CurInit.get()->getExprLoc(),
8507 diag::warn_cxx98_compat_initializer_list_init)
8508 << CurInit.get()->getSourceRange();
8509
8510 // Materialize the temporary into memory.
8511 MaterializeTemporaryExpr *MTE = S.CreateMaterializeTemporaryExpr(
8512 CurInit.get()->getType(), CurInit.get(),
8513 /*BoundToLvalueReference=*/false);
8514
8515 // Wrap it in a construction of a std::initializer_list<T>.
8516 CurInit = new (S.Context) CXXStdInitializerListExpr(Step->Type, MTE);
8517
8518 // Bind the result, in case the library has given initializer_list a
8519 // non-trivial destructor.
8520 if (shouldBindAsTemporary(Entity))
8521 CurInit = S.MaybeBindToTemporary(CurInit.get());
8522 break;
8523 }
8524
8525 case SK_OCLSamplerInit: {
8526 // Sampler initialization have 5 cases:
8527 // 1. function argument passing
8528 // 1a. argument is a file-scope variable
8529 // 1b. argument is a function-scope variable
8530 // 1c. argument is one of caller function's parameters
8531 // 2. variable initialization
8532 // 2a. initializing a file-scope variable
8533 // 2b. initializing a function-scope variable
8534 //
8535 // For file-scope variables, since they cannot be initialized by function
8536 // call of __translate_sampler_initializer in LLVM IR, their references
8537 // need to be replaced by a cast from their literal initializers to
8538 // sampler type. Since sampler variables can only be used in function
8539 // calls as arguments, we only need to replace them when handling the
8540 // argument passing.
8541 assert(Step->Type->isSamplerT() &&
8542 "Sampler initialization on non-sampler type.");
8543 Expr *Init = CurInit.get()->IgnoreParens();
8544 QualType SourceType = Init->getType();
8545 // Case 1
8546 if (Entity.isParameterKind()) {
8547 if (!SourceType->isSamplerT() && !SourceType->isIntegerType()) {
8548 S.Diag(Kind.getLocation(), diag::err_sampler_argument_required)
8549 << SourceType;
8550 break;
8551 } else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Init)) {
8552 auto Var = cast<VarDecl>(DRE->getDecl());
8553 // Case 1b and 1c
8554 // No cast from integer to sampler is needed.
8555 if (!Var->hasGlobalStorage()) {
8556 CurInit = ImplicitCastExpr::Create(S.Context, Step->Type,
8557 CK_LValueToRValue, Init,
8558 /*BasePath=*/nullptr, VK_RValue);
8559 break;
8560 }
8561 // Case 1a
8562 // For function call with a file-scope sampler variable as argument,
8563 // get the integer literal.
8564 // Do not diagnose if the file-scope variable does not have initializer
8565 // since this has already been diagnosed when parsing the variable
8566 // declaration.
8567 if (!Var->getInit() || !isa<ImplicitCastExpr>(Var->getInit()))
8568 break;
8569 Init = cast<ImplicitCastExpr>(const_cast<Expr*>(
8570 Var->getInit()))->getSubExpr();
8571 SourceType = Init->getType();
8572 }
8573 } else {
8574 // Case 2
8575 // Check initializer is 32 bit integer constant.
8576 // If the initializer is taken from global variable, do not diagnose since
8577 // this has already been done when parsing the variable declaration.
8578 if (!Init->isConstantInitializer(S.Context, false))
8579 break;
8580
8581 if (!SourceType->isIntegerType() ||
8582 32 != S.Context.getIntWidth(SourceType)) {
8583 S.Diag(Kind.getLocation(), diag::err_sampler_initializer_not_integer)
8584 << SourceType;
8585 break;
8586 }
8587
8588 Expr::EvalResult EVResult;
8589 Init->EvaluateAsInt(EVResult, S.Context);
8590 llvm::APSInt Result = EVResult.Val.getInt();
8591 const uint64_t SamplerValue = Result.getLimitedValue();
8592 // 32-bit value of sampler's initializer is interpreted as
8593 // bit-field with the following structure:
8594 // |unspecified|Filter|Addressing Mode| Normalized Coords|
8595 // |31 6|5 4|3 1| 0|
8596 // This structure corresponds to enum values of sampler properties
8597 // defined in SPIR spec v1.2 and also opencl-c.h
8598 unsigned AddressingMode = (0x0E & SamplerValue) >> 1;
8599 unsigned FilterMode = (0x30 & SamplerValue) >> 4;
8600 if (FilterMode != 1 && FilterMode != 2 &&
8601 !S.getOpenCLOptions().isEnabled(
8602 "cl_intel_device_side_avc_motion_estimation"))
8603 S.Diag(Kind.getLocation(),
8604 diag::warn_sampler_initializer_invalid_bits)
8605 << "Filter Mode";
8606 if (AddressingMode > 4)
8607 S.Diag(Kind.getLocation(),
8608 diag::warn_sampler_initializer_invalid_bits)
8609 << "Addressing Mode";
8610 }
8611
8612 // Cases 1a, 2a and 2b
8613 // Insert cast from integer to sampler.
8614 CurInit = S.ImpCastExprToType(Init, S.Context.OCLSamplerTy,
8615 CK_IntToOCLSampler);
8616 break;
8617 }
8618 case SK_OCLZeroOpaqueType: {
8619 assert((Step->Type->isEventT() || Step->Type->isQueueT() ||
8620 Step->Type->isOCLIntelSubgroupAVCType()) &&
8621 "Wrong type for initialization of OpenCL opaque type.");
8622
8623 CurInit = S.ImpCastExprToType(CurInit.get(), Step->Type,
8624 CK_ZeroToOCLOpaqueType,
8625 CurInit.get()->getValueKind());
8626 break;
8627 }
8628 }
8629 }
8630
8631 // Check whether the initializer has a shorter lifetime than the initialized
8632 // entity, and if not, either lifetime-extend or warn as appropriate.
8633 if (auto *Init = CurInit.get())
8634 S.checkInitializerLifetime(Entity, Init);
8635
8636 // Diagnose non-fatal problems with the completed initialization.
8637 if (Entity.getKind() == InitializedEntity::EK_Member &&
8638 cast<FieldDecl>(Entity.getDecl())->isBitField())
8639 S.CheckBitFieldInitialization(Kind.getLocation(),
8640 cast<FieldDecl>(Entity.getDecl()),
8641 CurInit.get());
8642
8643 // Check for std::move on construction.
8644 if (const Expr *E = CurInit.get()) {
8645 CheckMoveOnConstruction(S, E,
8646 Entity.getKind() == InitializedEntity::EK_Result);
8647 }
8648
8649 return CurInit;
8650 }
8651
8652 /// Somewhere within T there is an uninitialized reference subobject.
8653 /// Dig it out and diagnose it.
DiagnoseUninitializedReference(Sema & S,SourceLocation Loc,QualType T)8654 static bool DiagnoseUninitializedReference(Sema &S, SourceLocation Loc,
8655 QualType T) {
8656 if (T->isReferenceType()) {
8657 S.Diag(Loc, diag::err_reference_without_init)
8658 << T.getNonReferenceType();
8659 return true;
8660 }
8661
8662 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
8663 if (!RD || !RD->hasUninitializedReferenceMember())
8664 return false;
8665
8666 for (const auto *FI : RD->fields()) {
8667 if (FI->isUnnamedBitfield())
8668 continue;
8669
8670 if (DiagnoseUninitializedReference(S, FI->getLocation(), FI->getType())) {
8671 S.Diag(Loc, diag::note_value_initialization_here) << RD;
8672 return true;
8673 }
8674 }
8675
8676 for (const auto &BI : RD->bases()) {
8677 if (DiagnoseUninitializedReference(S, BI.getBeginLoc(), BI.getType())) {
8678 S.Diag(Loc, diag::note_value_initialization_here) << RD;
8679 return true;
8680 }
8681 }
8682
8683 return false;
8684 }
8685
8686
8687 //===----------------------------------------------------------------------===//
8688 // Diagnose initialization failures
8689 //===----------------------------------------------------------------------===//
8690
8691 /// Emit notes associated with an initialization that failed due to a
8692 /// "simple" conversion failure.
emitBadConversionNotes(Sema & S,const InitializedEntity & entity,Expr * op)8693 static void emitBadConversionNotes(Sema &S, const InitializedEntity &entity,
8694 Expr *op) {
8695 QualType destType = entity.getType();
8696 if (destType.getNonReferenceType()->isObjCObjectPointerType() &&
8697 op->getType()->isObjCObjectPointerType()) {
8698
8699 // Emit a possible note about the conversion failing because the
8700 // operand is a message send with a related result type.
8701 S.EmitRelatedResultTypeNote(op);
8702
8703 // Emit a possible note about a return failing because we're
8704 // expecting a related result type.
8705 if (entity.getKind() == InitializedEntity::EK_Result)
8706 S.EmitRelatedResultTypeNoteForReturn(destType);
8707 }
8708 }
8709
diagnoseListInit(Sema & S,const InitializedEntity & Entity,InitListExpr * InitList)8710 static void diagnoseListInit(Sema &S, const InitializedEntity &Entity,
8711 InitListExpr *InitList) {
8712 QualType DestType = Entity.getType();
8713
8714 QualType E;
8715 if (S.getLangOpts().CPlusPlus11 && S.isStdInitializerList(DestType, &E)) {
8716 QualType ArrayType = S.Context.getConstantArrayType(
8717 E.withConst(),
8718 llvm::APInt(S.Context.getTypeSize(S.Context.getSizeType()),
8719 InitList->getNumInits()),
8720 nullptr, clang::ArrayType::Normal, 0);
8721 InitializedEntity HiddenArray =
8722 InitializedEntity::InitializeTemporary(ArrayType);
8723 return diagnoseListInit(S, HiddenArray, InitList);
8724 }
8725
8726 if (DestType->isReferenceType()) {
8727 // A list-initialization failure for a reference means that we tried to
8728 // create a temporary of the inner type (per [dcl.init.list]p3.6) and the
8729 // inner initialization failed.
8730 QualType T = DestType->castAs<ReferenceType>()->getPointeeType();
8731 diagnoseListInit(S, InitializedEntity::InitializeTemporary(T), InitList);
8732 SourceLocation Loc = InitList->getBeginLoc();
8733 if (auto *D = Entity.getDecl())
8734 Loc = D->getLocation();
8735 S.Diag(Loc, diag::note_in_reference_temporary_list_initializer) << T;
8736 return;
8737 }
8738
8739 InitListChecker DiagnoseInitList(S, Entity, InitList, DestType,
8740 /*VerifyOnly=*/false,
8741 /*TreatUnavailableAsInvalid=*/false);
8742 assert(DiagnoseInitList.HadError() &&
8743 "Inconsistent init list check result.");
8744 }
8745
Diagnose(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,ArrayRef<Expr * > Args)8746 bool InitializationSequence::Diagnose(Sema &S,
8747 const InitializedEntity &Entity,
8748 const InitializationKind &Kind,
8749 ArrayRef<Expr *> Args) {
8750 if (!Failed())
8751 return false;
8752
8753 // When we want to diagnose only one element of a braced-init-list,
8754 // we need to factor it out.
8755 Expr *OnlyArg;
8756 if (Args.size() == 1) {
8757 auto *List = dyn_cast<InitListExpr>(Args[0]);
8758 if (List && List->getNumInits() == 1)
8759 OnlyArg = List->getInit(0);
8760 else
8761 OnlyArg = Args[0];
8762 }
8763 else
8764 OnlyArg = nullptr;
8765
8766 QualType DestType = Entity.getType();
8767 switch (Failure) {
8768 case FK_TooManyInitsForReference:
8769 // FIXME: Customize for the initialized entity?
8770 if (Args.empty()) {
8771 // Dig out the reference subobject which is uninitialized and diagnose it.
8772 // If this is value-initialization, this could be nested some way within
8773 // the target type.
8774 assert(Kind.getKind() == InitializationKind::IK_Value ||
8775 DestType->isReferenceType());
8776 bool Diagnosed =
8777 DiagnoseUninitializedReference(S, Kind.getLocation(), DestType);
8778 assert(Diagnosed && "couldn't find uninitialized reference to diagnose");
8779 (void)Diagnosed;
8780 } else // FIXME: diagnostic below could be better!
8781 S.Diag(Kind.getLocation(), diag::err_reference_has_multiple_inits)
8782 << SourceRange(Args.front()->getBeginLoc(), Args.back()->getEndLoc());
8783 break;
8784 case FK_ParenthesizedListInitForReference:
8785 S.Diag(Kind.getLocation(), diag::err_list_init_in_parens)
8786 << 1 << Entity.getType() << Args[0]->getSourceRange();
8787 break;
8788
8789 case FK_ArrayNeedsInitList:
8790 S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 0;
8791 break;
8792 case FK_ArrayNeedsInitListOrStringLiteral:
8793 S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 1;
8794 break;
8795 case FK_ArrayNeedsInitListOrWideStringLiteral:
8796 S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 2;
8797 break;
8798 case FK_NarrowStringIntoWideCharArray:
8799 S.Diag(Kind.getLocation(), diag::err_array_init_narrow_string_into_wchar);
8800 break;
8801 case FK_WideStringIntoCharArray:
8802 S.Diag(Kind.getLocation(), diag::err_array_init_wide_string_into_char);
8803 break;
8804 case FK_IncompatWideStringIntoWideChar:
8805 S.Diag(Kind.getLocation(),
8806 diag::err_array_init_incompat_wide_string_into_wchar);
8807 break;
8808 case FK_PlainStringIntoUTF8Char:
8809 S.Diag(Kind.getLocation(),
8810 diag::err_array_init_plain_string_into_char8_t);
8811 S.Diag(Args.front()->getBeginLoc(),
8812 diag::note_array_init_plain_string_into_char8_t)
8813 << FixItHint::CreateInsertion(Args.front()->getBeginLoc(), "u8");
8814 break;
8815 case FK_UTF8StringIntoPlainChar:
8816 S.Diag(Kind.getLocation(),
8817 diag::err_array_init_utf8_string_into_char)
8818 << S.getLangOpts().CPlusPlus20;
8819 break;
8820 case FK_ArrayTypeMismatch:
8821 case FK_NonConstantArrayInit:
8822 S.Diag(Kind.getLocation(),
8823 (Failure == FK_ArrayTypeMismatch
8824 ? diag::err_array_init_different_type
8825 : diag::err_array_init_non_constant_array))
8826 << DestType.getNonReferenceType()
8827 << OnlyArg->getType()
8828 << Args[0]->getSourceRange();
8829 break;
8830
8831 case FK_VariableLengthArrayHasInitializer:
8832 S.Diag(Kind.getLocation(), diag::err_variable_object_no_init)
8833 << Args[0]->getSourceRange();
8834 break;
8835
8836 case FK_AddressOfOverloadFailed: {
8837 DeclAccessPair Found;
8838 S.ResolveAddressOfOverloadedFunction(OnlyArg,
8839 DestType.getNonReferenceType(),
8840 true,
8841 Found);
8842 break;
8843 }
8844
8845 case FK_AddressOfUnaddressableFunction: {
8846 auto *FD = cast<FunctionDecl>(cast<DeclRefExpr>(OnlyArg)->getDecl());
8847 S.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true,
8848 OnlyArg->getBeginLoc());
8849 break;
8850 }
8851
8852 case FK_ReferenceInitOverloadFailed:
8853 case FK_UserConversionOverloadFailed:
8854 switch (FailedOverloadResult) {
8855 case OR_Ambiguous:
8856
8857 FailedCandidateSet.NoteCandidates(
8858 PartialDiagnosticAt(
8859 Kind.getLocation(),
8860 Failure == FK_UserConversionOverloadFailed
8861 ? (S.PDiag(diag::err_typecheck_ambiguous_condition)
8862 << OnlyArg->getType() << DestType
8863 << Args[0]->getSourceRange())
8864 : (S.PDiag(diag::err_ref_init_ambiguous)
8865 << DestType << OnlyArg->getType()
8866 << Args[0]->getSourceRange())),
8867 S, OCD_AmbiguousCandidates, Args);
8868 break;
8869
8870 case OR_No_Viable_Function: {
8871 auto Cands = FailedCandidateSet.CompleteCandidates(S, OCD_AllCandidates, Args);
8872 if (!S.RequireCompleteType(Kind.getLocation(),
8873 DestType.getNonReferenceType(),
8874 diag::err_typecheck_nonviable_condition_incomplete,
8875 OnlyArg->getType(), Args[0]->getSourceRange()))
8876 S.Diag(Kind.getLocation(), diag::err_typecheck_nonviable_condition)
8877 << (Entity.getKind() == InitializedEntity::EK_Result)
8878 << OnlyArg->getType() << Args[0]->getSourceRange()
8879 << DestType.getNonReferenceType();
8880
8881 FailedCandidateSet.NoteCandidates(S, Args, Cands);
8882 break;
8883 }
8884 case OR_Deleted: {
8885 S.Diag(Kind.getLocation(), diag::err_typecheck_deleted_function)
8886 << OnlyArg->getType() << DestType.getNonReferenceType()
8887 << Args[0]->getSourceRange();
8888 OverloadCandidateSet::iterator Best;
8889 OverloadingResult Ovl
8890 = FailedCandidateSet.BestViableFunction(S, Kind.getLocation(), Best);
8891 if (Ovl == OR_Deleted) {
8892 S.NoteDeletedFunction(Best->Function);
8893 } else {
8894 llvm_unreachable("Inconsistent overload resolution?");
8895 }
8896 break;
8897 }
8898
8899 case OR_Success:
8900 llvm_unreachable("Conversion did not fail!");
8901 }
8902 break;
8903
8904 case FK_NonConstLValueReferenceBindingToTemporary:
8905 if (isa<InitListExpr>(Args[0])) {
8906 S.Diag(Kind.getLocation(),
8907 diag::err_lvalue_reference_bind_to_initlist)
8908 << DestType.getNonReferenceType().isVolatileQualified()
8909 << DestType.getNonReferenceType()
8910 << Args[0]->getSourceRange();
8911 break;
8912 }
8913 LLVM_FALLTHROUGH;
8914
8915 case FK_NonConstLValueReferenceBindingToUnrelated:
8916 S.Diag(Kind.getLocation(),
8917 Failure == FK_NonConstLValueReferenceBindingToTemporary
8918 ? diag::err_lvalue_reference_bind_to_temporary
8919 : diag::err_lvalue_reference_bind_to_unrelated)
8920 << DestType.getNonReferenceType().isVolatileQualified()
8921 << DestType.getNonReferenceType()
8922 << OnlyArg->getType()
8923 << Args[0]->getSourceRange();
8924 break;
8925
8926 case FK_NonConstLValueReferenceBindingToBitfield: {
8927 // We don't necessarily have an unambiguous source bit-field.
8928 FieldDecl *BitField = Args[0]->getSourceBitField();
8929 S.Diag(Kind.getLocation(), diag::err_reference_bind_to_bitfield)
8930 << DestType.isVolatileQualified()
8931 << (BitField ? BitField->getDeclName() : DeclarationName())
8932 << (BitField != nullptr)
8933 << Args[0]->getSourceRange();
8934 if (BitField)
8935 S.Diag(BitField->getLocation(), diag::note_bitfield_decl);
8936 break;
8937 }
8938
8939 case FK_NonConstLValueReferenceBindingToVectorElement:
8940 S.Diag(Kind.getLocation(), diag::err_reference_bind_to_vector_element)
8941 << DestType.isVolatileQualified()
8942 << Args[0]->getSourceRange();
8943 break;
8944
8945 case FK_NonConstLValueReferenceBindingToMatrixElement:
8946 S.Diag(Kind.getLocation(), diag::err_reference_bind_to_matrix_element)
8947 << DestType.isVolatileQualified() << Args[0]->getSourceRange();
8948 break;
8949
8950 case FK_RValueReferenceBindingToLValue:
8951 S.Diag(Kind.getLocation(), diag::err_lvalue_to_rvalue_ref)
8952 << DestType.getNonReferenceType() << OnlyArg->getType()
8953 << Args[0]->getSourceRange();
8954 break;
8955
8956 case FK_ReferenceAddrspaceMismatchTemporary:
8957 S.Diag(Kind.getLocation(), diag::err_reference_bind_temporary_addrspace)
8958 << DestType << Args[0]->getSourceRange();
8959 break;
8960
8961 case FK_ReferenceInitDropsQualifiers: {
8962 QualType SourceType = OnlyArg->getType();
8963 QualType NonRefType = DestType.getNonReferenceType();
8964 Qualifiers DroppedQualifiers =
8965 SourceType.getQualifiers() - NonRefType.getQualifiers();
8966
8967 if (!NonRefType.getQualifiers().isAddressSpaceSupersetOf(
8968 SourceType.getQualifiers()))
8969 S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
8970 << NonRefType << SourceType << 1 /*addr space*/
8971 << Args[0]->getSourceRange();
8972 else if (DroppedQualifiers.hasQualifiers())
8973 S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
8974 << NonRefType << SourceType << 0 /*cv quals*/
8975 << Qualifiers::fromCVRMask(DroppedQualifiers.getCVRQualifiers())
8976 << DroppedQualifiers.getCVRQualifiers() << Args[0]->getSourceRange();
8977 else
8978 // FIXME: Consider decomposing the type and explaining which qualifiers
8979 // were dropped where, or on which level a 'const' is missing, etc.
8980 S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
8981 << NonRefType << SourceType << 2 /*incompatible quals*/
8982 << Args[0]->getSourceRange();
8983 break;
8984 }
8985
8986 case FK_ReferenceInitFailed:
8987 S.Diag(Kind.getLocation(), diag::err_reference_bind_failed)
8988 << DestType.getNonReferenceType()
8989 << DestType.getNonReferenceType()->isIncompleteType()
8990 << OnlyArg->isLValue()
8991 << OnlyArg->getType()
8992 << Args[0]->getSourceRange();
8993 emitBadConversionNotes(S, Entity, Args[0]);
8994 break;
8995
8996 case FK_ConversionFailed: {
8997 QualType FromType = OnlyArg->getType();
8998 PartialDiagnostic PDiag = S.PDiag(diag::err_init_conversion_failed)
8999 << (int)Entity.getKind()
9000 << DestType
9001 << OnlyArg->isLValue()
9002 << FromType
9003 << Args[0]->getSourceRange();
9004 S.HandleFunctionTypeMismatch(PDiag, FromType, DestType);
9005 S.Diag(Kind.getLocation(), PDiag);
9006 emitBadConversionNotes(S, Entity, Args[0]);
9007 break;
9008 }
9009
9010 case FK_ConversionFromPropertyFailed:
9011 // No-op. This error has already been reported.
9012 break;
9013
9014 case FK_TooManyInitsForScalar: {
9015 SourceRange R;
9016
9017 auto *InitList = dyn_cast<InitListExpr>(Args[0]);
9018 if (InitList && InitList->getNumInits() >= 1) {
9019 R = SourceRange(InitList->getInit(0)->getEndLoc(), InitList->getEndLoc());
9020 } else {
9021 assert(Args.size() > 1 && "Expected multiple initializers!");
9022 R = SourceRange(Args.front()->getEndLoc(), Args.back()->getEndLoc());
9023 }
9024
9025 R.setBegin(S.getLocForEndOfToken(R.getBegin()));
9026 if (Kind.isCStyleOrFunctionalCast())
9027 S.Diag(Kind.getLocation(), diag::err_builtin_func_cast_more_than_one_arg)
9028 << R;
9029 else
9030 S.Diag(Kind.getLocation(), diag::err_excess_initializers)
9031 << /*scalar=*/2 << R;
9032 break;
9033 }
9034
9035 case FK_ParenthesizedListInitForScalar:
9036 S.Diag(Kind.getLocation(), diag::err_list_init_in_parens)
9037 << 0 << Entity.getType() << Args[0]->getSourceRange();
9038 break;
9039
9040 case FK_ReferenceBindingToInitList:
9041 S.Diag(Kind.getLocation(), diag::err_reference_bind_init_list)
9042 << DestType.getNonReferenceType() << Args[0]->getSourceRange();
9043 break;
9044
9045 case FK_InitListBadDestinationType:
9046 S.Diag(Kind.getLocation(), diag::err_init_list_bad_dest_type)
9047 << (DestType->isRecordType()) << DestType << Args[0]->getSourceRange();
9048 break;
9049
9050 case FK_ListConstructorOverloadFailed:
9051 case FK_ConstructorOverloadFailed: {
9052 SourceRange ArgsRange;
9053 if (Args.size())
9054 ArgsRange =
9055 SourceRange(Args.front()->getBeginLoc(), Args.back()->getEndLoc());
9056
9057 if (Failure == FK_ListConstructorOverloadFailed) {
9058 assert(Args.size() == 1 &&
9059 "List construction from other than 1 argument.");
9060 InitListExpr *InitList = cast<InitListExpr>(Args[0]);
9061 Args = MultiExprArg(InitList->getInits(), InitList->getNumInits());
9062 }
9063
9064 // FIXME: Using "DestType" for the entity we're printing is probably
9065 // bad.
9066 switch (FailedOverloadResult) {
9067 case OR_Ambiguous:
9068 FailedCandidateSet.NoteCandidates(
9069 PartialDiagnosticAt(Kind.getLocation(),
9070 S.PDiag(diag::err_ovl_ambiguous_init)
9071 << DestType << ArgsRange),
9072 S, OCD_AmbiguousCandidates, Args);
9073 break;
9074
9075 case OR_No_Viable_Function:
9076 if (Kind.getKind() == InitializationKind::IK_Default &&
9077 (Entity.getKind() == InitializedEntity::EK_Base ||
9078 Entity.getKind() == InitializedEntity::EK_Member) &&
9079 isa<CXXConstructorDecl>(S.CurContext)) {
9080 // This is implicit default initialization of a member or
9081 // base within a constructor. If no viable function was
9082 // found, notify the user that they need to explicitly
9083 // initialize this base/member.
9084 CXXConstructorDecl *Constructor
9085 = cast<CXXConstructorDecl>(S.CurContext);
9086 const CXXRecordDecl *InheritedFrom = nullptr;
9087 if (auto Inherited = Constructor->getInheritedConstructor())
9088 InheritedFrom = Inherited.getShadowDecl()->getNominatedBaseClass();
9089 if (Entity.getKind() == InitializedEntity::EK_Base) {
9090 S.Diag(Kind.getLocation(), diag::err_missing_default_ctor)
9091 << (InheritedFrom ? 2 : Constructor->isImplicit() ? 1 : 0)
9092 << S.Context.getTypeDeclType(Constructor->getParent())
9093 << /*base=*/0
9094 << Entity.getType()
9095 << InheritedFrom;
9096
9097 RecordDecl *BaseDecl
9098 = Entity.getBaseSpecifier()->getType()->castAs<RecordType>()
9099 ->getDecl();
9100 S.Diag(BaseDecl->getLocation(), diag::note_previous_decl)
9101 << S.Context.getTagDeclType(BaseDecl);
9102 } else {
9103 S.Diag(Kind.getLocation(), diag::err_missing_default_ctor)
9104 << (InheritedFrom ? 2 : Constructor->isImplicit() ? 1 : 0)
9105 << S.Context.getTypeDeclType(Constructor->getParent())
9106 << /*member=*/1
9107 << Entity.getName()
9108 << InheritedFrom;
9109 S.Diag(Entity.getDecl()->getLocation(),
9110 diag::note_member_declared_at);
9111
9112 if (const RecordType *Record
9113 = Entity.getType()->getAs<RecordType>())
9114 S.Diag(Record->getDecl()->getLocation(),
9115 diag::note_previous_decl)
9116 << S.Context.getTagDeclType(Record->getDecl());
9117 }
9118 break;
9119 }
9120
9121 FailedCandidateSet.NoteCandidates(
9122 PartialDiagnosticAt(
9123 Kind.getLocation(),
9124 S.PDiag(diag::err_ovl_no_viable_function_in_init)
9125 << DestType << ArgsRange),
9126 S, OCD_AllCandidates, Args);
9127 break;
9128
9129 case OR_Deleted: {
9130 OverloadCandidateSet::iterator Best;
9131 OverloadingResult Ovl
9132 = FailedCandidateSet.BestViableFunction(S, Kind.getLocation(), Best);
9133 if (Ovl != OR_Deleted) {
9134 S.Diag(Kind.getLocation(), diag::err_ovl_deleted_init)
9135 << DestType << ArgsRange;
9136 llvm_unreachable("Inconsistent overload resolution?");
9137 break;
9138 }
9139
9140 // If this is a defaulted or implicitly-declared function, then
9141 // it was implicitly deleted. Make it clear that the deletion was
9142 // implicit.
9143 if (S.isImplicitlyDeleted(Best->Function))
9144 S.Diag(Kind.getLocation(), diag::err_ovl_deleted_special_init)
9145 << S.getSpecialMember(cast<CXXMethodDecl>(Best->Function))
9146 << DestType << ArgsRange;
9147 else
9148 S.Diag(Kind.getLocation(), diag::err_ovl_deleted_init)
9149 << DestType << ArgsRange;
9150
9151 S.NoteDeletedFunction(Best->Function);
9152 break;
9153 }
9154
9155 case OR_Success:
9156 llvm_unreachable("Conversion did not fail!");
9157 }
9158 }
9159 break;
9160
9161 case FK_DefaultInitOfConst:
9162 if (Entity.getKind() == InitializedEntity::EK_Member &&
9163 isa<CXXConstructorDecl>(S.CurContext)) {
9164 // This is implicit default-initialization of a const member in
9165 // a constructor. Complain that it needs to be explicitly
9166 // initialized.
9167 CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(S.CurContext);
9168 S.Diag(Kind.getLocation(), diag::err_uninitialized_member_in_ctor)
9169 << (Constructor->getInheritedConstructor() ? 2 :
9170 Constructor->isImplicit() ? 1 : 0)
9171 << S.Context.getTypeDeclType(Constructor->getParent())
9172 << /*const=*/1
9173 << Entity.getName();
9174 S.Diag(Entity.getDecl()->getLocation(), diag::note_previous_decl)
9175 << Entity.getName();
9176 } else {
9177 S.Diag(Kind.getLocation(), diag::err_default_init_const)
9178 << DestType << (bool)DestType->getAs<RecordType>();
9179 }
9180 break;
9181
9182 case FK_Incomplete:
9183 S.RequireCompleteType(Kind.getLocation(), FailedIncompleteType,
9184 diag::err_init_incomplete_type);
9185 break;
9186
9187 case FK_ListInitializationFailed: {
9188 // Run the init list checker again to emit diagnostics.
9189 InitListExpr *InitList = cast<InitListExpr>(Args[0]);
9190 diagnoseListInit(S, Entity, InitList);
9191 break;
9192 }
9193
9194 case FK_PlaceholderType: {
9195 // FIXME: Already diagnosed!
9196 break;
9197 }
9198
9199 case FK_ExplicitConstructor: {
9200 S.Diag(Kind.getLocation(), diag::err_selected_explicit_constructor)
9201 << Args[0]->getSourceRange();
9202 OverloadCandidateSet::iterator Best;
9203 OverloadingResult Ovl
9204 = FailedCandidateSet.BestViableFunction(S, Kind.getLocation(), Best);
9205 (void)Ovl;
9206 assert(Ovl == OR_Success && "Inconsistent overload resolution");
9207 CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
9208 S.Diag(CtorDecl->getLocation(),
9209 diag::note_explicit_ctor_deduction_guide_here) << false;
9210 break;
9211 }
9212 }
9213
9214 PrintInitLocationNote(S, Entity);
9215 return true;
9216 }
9217
dump(raw_ostream & OS) const9218 void InitializationSequence::dump(raw_ostream &OS) const {
9219 switch (SequenceKind) {
9220 case FailedSequence: {
9221 OS << "Failed sequence: ";
9222 switch (Failure) {
9223 case FK_TooManyInitsForReference:
9224 OS << "too many initializers for reference";
9225 break;
9226
9227 case FK_ParenthesizedListInitForReference:
9228 OS << "parenthesized list init for reference";
9229 break;
9230
9231 case FK_ArrayNeedsInitList:
9232 OS << "array requires initializer list";
9233 break;
9234
9235 case FK_AddressOfUnaddressableFunction:
9236 OS << "address of unaddressable function was taken";
9237 break;
9238
9239 case FK_ArrayNeedsInitListOrStringLiteral:
9240 OS << "array requires initializer list or string literal";
9241 break;
9242
9243 case FK_ArrayNeedsInitListOrWideStringLiteral:
9244 OS << "array requires initializer list or wide string literal";
9245 break;
9246
9247 case FK_NarrowStringIntoWideCharArray:
9248 OS << "narrow string into wide char array";
9249 break;
9250
9251 case FK_WideStringIntoCharArray:
9252 OS << "wide string into char array";
9253 break;
9254
9255 case FK_IncompatWideStringIntoWideChar:
9256 OS << "incompatible wide string into wide char array";
9257 break;
9258
9259 case FK_PlainStringIntoUTF8Char:
9260 OS << "plain string literal into char8_t array";
9261 break;
9262
9263 case FK_UTF8StringIntoPlainChar:
9264 OS << "u8 string literal into char array";
9265 break;
9266
9267 case FK_ArrayTypeMismatch:
9268 OS << "array type mismatch";
9269 break;
9270
9271 case FK_NonConstantArrayInit:
9272 OS << "non-constant array initializer";
9273 break;
9274
9275 case FK_AddressOfOverloadFailed:
9276 OS << "address of overloaded function failed";
9277 break;
9278
9279 case FK_ReferenceInitOverloadFailed:
9280 OS << "overload resolution for reference initialization failed";
9281 break;
9282
9283 case FK_NonConstLValueReferenceBindingToTemporary:
9284 OS << "non-const lvalue reference bound to temporary";
9285 break;
9286
9287 case FK_NonConstLValueReferenceBindingToBitfield:
9288 OS << "non-const lvalue reference bound to bit-field";
9289 break;
9290
9291 case FK_NonConstLValueReferenceBindingToVectorElement:
9292 OS << "non-const lvalue reference bound to vector element";
9293 break;
9294
9295 case FK_NonConstLValueReferenceBindingToMatrixElement:
9296 OS << "non-const lvalue reference bound to matrix element";
9297 break;
9298
9299 case FK_NonConstLValueReferenceBindingToUnrelated:
9300 OS << "non-const lvalue reference bound to unrelated type";
9301 break;
9302
9303 case FK_RValueReferenceBindingToLValue:
9304 OS << "rvalue reference bound to an lvalue";
9305 break;
9306
9307 case FK_ReferenceInitDropsQualifiers:
9308 OS << "reference initialization drops qualifiers";
9309 break;
9310
9311 case FK_ReferenceAddrspaceMismatchTemporary:
9312 OS << "reference with mismatching address space bound to temporary";
9313 break;
9314
9315 case FK_ReferenceInitFailed:
9316 OS << "reference initialization failed";
9317 break;
9318
9319 case FK_ConversionFailed:
9320 OS << "conversion failed";
9321 break;
9322
9323 case FK_ConversionFromPropertyFailed:
9324 OS << "conversion from property failed";
9325 break;
9326
9327 case FK_TooManyInitsForScalar:
9328 OS << "too many initializers for scalar";
9329 break;
9330
9331 case FK_ParenthesizedListInitForScalar:
9332 OS << "parenthesized list init for reference";
9333 break;
9334
9335 case FK_ReferenceBindingToInitList:
9336 OS << "referencing binding to initializer list";
9337 break;
9338
9339 case FK_InitListBadDestinationType:
9340 OS << "initializer list for non-aggregate, non-scalar type";
9341 break;
9342
9343 case FK_UserConversionOverloadFailed:
9344 OS << "overloading failed for user-defined conversion";
9345 break;
9346
9347 case FK_ConstructorOverloadFailed:
9348 OS << "constructor overloading failed";
9349 break;
9350
9351 case FK_DefaultInitOfConst:
9352 OS << "default initialization of a const variable";
9353 break;
9354
9355 case FK_Incomplete:
9356 OS << "initialization of incomplete type";
9357 break;
9358
9359 case FK_ListInitializationFailed:
9360 OS << "list initialization checker failure";
9361 break;
9362
9363 case FK_VariableLengthArrayHasInitializer:
9364 OS << "variable length array has an initializer";
9365 break;
9366
9367 case FK_PlaceholderType:
9368 OS << "initializer expression isn't contextually valid";
9369 break;
9370
9371 case FK_ListConstructorOverloadFailed:
9372 OS << "list constructor overloading failed";
9373 break;
9374
9375 case FK_ExplicitConstructor:
9376 OS << "list copy initialization chose explicit constructor";
9377 break;
9378 }
9379 OS << '\n';
9380 return;
9381 }
9382
9383 case DependentSequence:
9384 OS << "Dependent sequence\n";
9385 return;
9386
9387 case NormalSequence:
9388 OS << "Normal sequence: ";
9389 break;
9390 }
9391
9392 for (step_iterator S = step_begin(), SEnd = step_end(); S != SEnd; ++S) {
9393 if (S != step_begin()) {
9394 OS << " -> ";
9395 }
9396
9397 switch (S->Kind) {
9398 case SK_ResolveAddressOfOverloadedFunction:
9399 OS << "resolve address of overloaded function";
9400 break;
9401
9402 case SK_CastDerivedToBaseRValue:
9403 OS << "derived-to-base (rvalue)";
9404 break;
9405
9406 case SK_CastDerivedToBaseXValue:
9407 OS << "derived-to-base (xvalue)";
9408 break;
9409
9410 case SK_CastDerivedToBaseLValue:
9411 OS << "derived-to-base (lvalue)";
9412 break;
9413
9414 case SK_BindReference:
9415 OS << "bind reference to lvalue";
9416 break;
9417
9418 case SK_BindReferenceToTemporary:
9419 OS << "bind reference to a temporary";
9420 break;
9421
9422 case SK_FinalCopy:
9423 OS << "final copy in class direct-initialization";
9424 break;
9425
9426 case SK_ExtraneousCopyToTemporary:
9427 OS << "extraneous C++03 copy to temporary";
9428 break;
9429
9430 case SK_UserConversion:
9431 OS << "user-defined conversion via " << *S->Function.Function;
9432 break;
9433
9434 case SK_QualificationConversionRValue:
9435 OS << "qualification conversion (rvalue)";
9436 break;
9437
9438 case SK_QualificationConversionXValue:
9439 OS << "qualification conversion (xvalue)";
9440 break;
9441
9442 case SK_QualificationConversionLValue:
9443 OS << "qualification conversion (lvalue)";
9444 break;
9445
9446 case SK_AtomicConversion:
9447 OS << "non-atomic-to-atomic conversion";
9448 break;
9449
9450 case SK_ConversionSequence:
9451 OS << "implicit conversion sequence (";
9452 S->ICS->dump(); // FIXME: use OS
9453 OS << ")";
9454 break;
9455
9456 case SK_ConversionSequenceNoNarrowing:
9457 OS << "implicit conversion sequence with narrowing prohibited (";
9458 S->ICS->dump(); // FIXME: use OS
9459 OS << ")";
9460 break;
9461
9462 case SK_ListInitialization:
9463 OS << "list aggregate initialization";
9464 break;
9465
9466 case SK_UnwrapInitList:
9467 OS << "unwrap reference initializer list";
9468 break;
9469
9470 case SK_RewrapInitList:
9471 OS << "rewrap reference initializer list";
9472 break;
9473
9474 case SK_ConstructorInitialization:
9475 OS << "constructor initialization";
9476 break;
9477
9478 case SK_ConstructorInitializationFromList:
9479 OS << "list initialization via constructor";
9480 break;
9481
9482 case SK_ZeroInitialization:
9483 OS << "zero initialization";
9484 break;
9485
9486 case SK_CAssignment:
9487 OS << "C assignment";
9488 break;
9489
9490 case SK_StringInit:
9491 OS << "string initialization";
9492 break;
9493
9494 case SK_ObjCObjectConversion:
9495 OS << "Objective-C object conversion";
9496 break;
9497
9498 case SK_ArrayLoopIndex:
9499 OS << "indexing for array initialization loop";
9500 break;
9501
9502 case SK_ArrayLoopInit:
9503 OS << "array initialization loop";
9504 break;
9505
9506 case SK_ArrayInit:
9507 OS << "array initialization";
9508 break;
9509
9510 case SK_GNUArrayInit:
9511 OS << "array initialization (GNU extension)";
9512 break;
9513
9514 case SK_ParenthesizedArrayInit:
9515 OS << "parenthesized array initialization";
9516 break;
9517
9518 case SK_PassByIndirectCopyRestore:
9519 OS << "pass by indirect copy and restore";
9520 break;
9521
9522 case SK_PassByIndirectRestore:
9523 OS << "pass by indirect restore";
9524 break;
9525
9526 case SK_ProduceObjCObject:
9527 OS << "Objective-C object retension";
9528 break;
9529
9530 case SK_StdInitializerList:
9531 OS << "std::initializer_list from initializer list";
9532 break;
9533
9534 case SK_StdInitializerListConstructorCall:
9535 OS << "list initialization from std::initializer_list";
9536 break;
9537
9538 case SK_OCLSamplerInit:
9539 OS << "OpenCL sampler_t from integer constant";
9540 break;
9541
9542 case SK_OCLZeroOpaqueType:
9543 OS << "OpenCL opaque type from zero";
9544 break;
9545 }
9546
9547 OS << " [" << S->Type.getAsString() << ']';
9548 }
9549
9550 OS << '\n';
9551 }
9552
dump() const9553 void InitializationSequence::dump() const {
9554 dump(llvm::errs());
9555 }
9556
NarrowingErrs(const LangOptions & L)9557 static bool NarrowingErrs(const LangOptions &L) {
9558 return L.CPlusPlus11 &&
9559 (!L.MicrosoftExt || L.isCompatibleWithMSVC(LangOptions::MSVC2015));
9560 }
9561
DiagnoseNarrowingInInitList(Sema & S,const ImplicitConversionSequence & ICS,QualType PreNarrowingType,QualType EntityType,const Expr * PostInit)9562 static void DiagnoseNarrowingInInitList(Sema &S,
9563 const ImplicitConversionSequence &ICS,
9564 QualType PreNarrowingType,
9565 QualType EntityType,
9566 const Expr *PostInit) {
9567 const StandardConversionSequence *SCS = nullptr;
9568 switch (ICS.getKind()) {
9569 case ImplicitConversionSequence::StandardConversion:
9570 SCS = &ICS.Standard;
9571 break;
9572 case ImplicitConversionSequence::UserDefinedConversion:
9573 SCS = &ICS.UserDefined.After;
9574 break;
9575 case ImplicitConversionSequence::AmbiguousConversion:
9576 case ImplicitConversionSequence::EllipsisConversion:
9577 case ImplicitConversionSequence::BadConversion:
9578 return;
9579 }
9580
9581 // C++11 [dcl.init.list]p7: Check whether this is a narrowing conversion.
9582 APValue ConstantValue;
9583 QualType ConstantType;
9584 switch (SCS->getNarrowingKind(S.Context, PostInit, ConstantValue,
9585 ConstantType)) {
9586 case NK_Not_Narrowing:
9587 case NK_Dependent_Narrowing:
9588 // No narrowing occurred.
9589 return;
9590
9591 case NK_Type_Narrowing:
9592 // This was a floating-to-integer conversion, which is always considered a
9593 // narrowing conversion even if the value is a constant and can be
9594 // represented exactly as an integer.
9595 S.Diag(PostInit->getBeginLoc(), NarrowingErrs(S.getLangOpts())
9596 ? diag::ext_init_list_type_narrowing
9597 : diag::warn_init_list_type_narrowing)
9598 << PostInit->getSourceRange()
9599 << PreNarrowingType.getLocalUnqualifiedType()
9600 << EntityType.getLocalUnqualifiedType();
9601 break;
9602
9603 case NK_Constant_Narrowing:
9604 // A constant value was narrowed.
9605 S.Diag(PostInit->getBeginLoc(),
9606 NarrowingErrs(S.getLangOpts())
9607 ? diag::ext_init_list_constant_narrowing
9608 : diag::warn_init_list_constant_narrowing)
9609 << PostInit->getSourceRange()
9610 << ConstantValue.getAsString(S.getASTContext(), ConstantType)
9611 << EntityType.getLocalUnqualifiedType();
9612 break;
9613
9614 case NK_Variable_Narrowing:
9615 // A variable's value may have been narrowed.
9616 S.Diag(PostInit->getBeginLoc(),
9617 NarrowingErrs(S.getLangOpts())
9618 ? diag::ext_init_list_variable_narrowing
9619 : diag::warn_init_list_variable_narrowing)
9620 << PostInit->getSourceRange()
9621 << PreNarrowingType.getLocalUnqualifiedType()
9622 << EntityType.getLocalUnqualifiedType();
9623 break;
9624 }
9625
9626 SmallString<128> StaticCast;
9627 llvm::raw_svector_ostream OS(StaticCast);
9628 OS << "static_cast<";
9629 if (const TypedefType *TT = EntityType->getAs<TypedefType>()) {
9630 // It's important to use the typedef's name if there is one so that the
9631 // fixit doesn't break code using types like int64_t.
9632 //
9633 // FIXME: This will break if the typedef requires qualification. But
9634 // getQualifiedNameAsString() includes non-machine-parsable components.
9635 OS << *TT->getDecl();
9636 } else if (const BuiltinType *BT = EntityType->getAs<BuiltinType>())
9637 OS << BT->getName(S.getLangOpts());
9638 else {
9639 // Oops, we didn't find the actual type of the variable. Don't emit a fixit
9640 // with a broken cast.
9641 return;
9642 }
9643 OS << ">(";
9644 S.Diag(PostInit->getBeginLoc(), diag::note_init_list_narrowing_silence)
9645 << PostInit->getSourceRange()
9646 << FixItHint::CreateInsertion(PostInit->getBeginLoc(), OS.str())
9647 << FixItHint::CreateInsertion(
9648 S.getLocForEndOfToken(PostInit->getEndLoc()), ")");
9649 }
9650
9651 //===----------------------------------------------------------------------===//
9652 // Initialization helper functions
9653 //===----------------------------------------------------------------------===//
9654 bool
CanPerformCopyInitialization(const InitializedEntity & Entity,ExprResult Init)9655 Sema::CanPerformCopyInitialization(const InitializedEntity &Entity,
9656 ExprResult Init) {
9657 if (Init.isInvalid())
9658 return false;
9659
9660 Expr *InitE = Init.get();
9661 assert(InitE && "No initialization expression");
9662
9663 InitializationKind Kind =
9664 InitializationKind::CreateCopy(InitE->getBeginLoc(), SourceLocation());
9665 InitializationSequence Seq(*this, Entity, Kind, InitE);
9666 return !Seq.Failed();
9667 }
9668
9669 ExprResult
PerformCopyInitialization(const InitializedEntity & Entity,SourceLocation EqualLoc,ExprResult Init,bool TopLevelOfInitList,bool AllowExplicit)9670 Sema::PerformCopyInitialization(const InitializedEntity &Entity,
9671 SourceLocation EqualLoc,
9672 ExprResult Init,
9673 bool TopLevelOfInitList,
9674 bool AllowExplicit) {
9675 if (Init.isInvalid())
9676 return ExprError();
9677
9678 Expr *InitE = Init.get();
9679 assert(InitE && "No initialization expression?");
9680
9681 if (EqualLoc.isInvalid())
9682 EqualLoc = InitE->getBeginLoc();
9683
9684 InitializationKind Kind = InitializationKind::CreateCopy(
9685 InitE->getBeginLoc(), EqualLoc, AllowExplicit);
9686 InitializationSequence Seq(*this, Entity, Kind, InitE, TopLevelOfInitList);
9687
9688 // Prevent infinite recursion when performing parameter copy-initialization.
9689 const bool ShouldTrackCopy =
9690 Entity.isParameterKind() && Seq.isConstructorInitialization();
9691 if (ShouldTrackCopy) {
9692 if (llvm::find(CurrentParameterCopyTypes, Entity.getType()) !=
9693 CurrentParameterCopyTypes.end()) {
9694 Seq.SetOverloadFailure(
9695 InitializationSequence::FK_ConstructorOverloadFailed,
9696 OR_No_Viable_Function);
9697
9698 // Try to give a meaningful diagnostic note for the problematic
9699 // constructor.
9700 const auto LastStep = Seq.step_end() - 1;
9701 assert(LastStep->Kind ==
9702 InitializationSequence::SK_ConstructorInitialization);
9703 const FunctionDecl *Function = LastStep->Function.Function;
9704 auto Candidate =
9705 llvm::find_if(Seq.getFailedCandidateSet(),
9706 [Function](const OverloadCandidate &Candidate) -> bool {
9707 return Candidate.Viable &&
9708 Candidate.Function == Function &&
9709 Candidate.Conversions.size() > 0;
9710 });
9711 if (Candidate != Seq.getFailedCandidateSet().end() &&
9712 Function->getNumParams() > 0) {
9713 Candidate->Viable = false;
9714 Candidate->FailureKind = ovl_fail_bad_conversion;
9715 Candidate->Conversions[0].setBad(BadConversionSequence::no_conversion,
9716 InitE,
9717 Function->getParamDecl(0)->getType());
9718 }
9719 }
9720 CurrentParameterCopyTypes.push_back(Entity.getType());
9721 }
9722
9723 ExprResult Result = Seq.Perform(*this, Entity, Kind, InitE);
9724
9725 if (ShouldTrackCopy)
9726 CurrentParameterCopyTypes.pop_back();
9727
9728 return Result;
9729 }
9730
9731 /// Determine whether RD is, or is derived from, a specialization of CTD.
isOrIsDerivedFromSpecializationOf(CXXRecordDecl * RD,ClassTemplateDecl * CTD)9732 static bool isOrIsDerivedFromSpecializationOf(CXXRecordDecl *RD,
9733 ClassTemplateDecl *CTD) {
9734 auto NotSpecialization = [&] (const CXXRecordDecl *Candidate) {
9735 auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(Candidate);
9736 return !CTSD || !declaresSameEntity(CTSD->getSpecializedTemplate(), CTD);
9737 };
9738 return !(NotSpecialization(RD) && RD->forallBases(NotSpecialization));
9739 }
9740
DeduceTemplateSpecializationFromInitializer(TypeSourceInfo * TSInfo,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Inits)9741 QualType Sema::DeduceTemplateSpecializationFromInitializer(
9742 TypeSourceInfo *TSInfo, const InitializedEntity &Entity,
9743 const InitializationKind &Kind, MultiExprArg Inits) {
9744 auto *DeducedTST = dyn_cast<DeducedTemplateSpecializationType>(
9745 TSInfo->getType()->getContainedDeducedType());
9746 assert(DeducedTST && "not a deduced template specialization type");
9747
9748 auto TemplateName = DeducedTST->getTemplateName();
9749 if (TemplateName.isDependent())
9750 return Context.DependentTy;
9751
9752 // We can only perform deduction for class templates.
9753 auto *Template =
9754 dyn_cast_or_null<ClassTemplateDecl>(TemplateName.getAsTemplateDecl());
9755 if (!Template) {
9756 Diag(Kind.getLocation(),
9757 diag::err_deduced_non_class_template_specialization_type)
9758 << (int)getTemplateNameKindForDiagnostics(TemplateName) << TemplateName;
9759 if (auto *TD = TemplateName.getAsTemplateDecl())
9760 Diag(TD->getLocation(), diag::note_template_decl_here);
9761 return QualType();
9762 }
9763
9764 // Can't deduce from dependent arguments.
9765 if (Expr::hasAnyTypeDependentArguments(Inits)) {
9766 Diag(TSInfo->getTypeLoc().getBeginLoc(),
9767 diag::warn_cxx14_compat_class_template_argument_deduction)
9768 << TSInfo->getTypeLoc().getSourceRange() << 0;
9769 return Context.DependentTy;
9770 }
9771
9772 // FIXME: Perform "exact type" matching first, per CWG discussion?
9773 // Or implement this via an implied 'T(T) -> T' deduction guide?
9774
9775 // FIXME: Do we need/want a std::initializer_list<T> special case?
9776
9777 // Look up deduction guides, including those synthesized from constructors.
9778 //
9779 // C++1z [over.match.class.deduct]p1:
9780 // A set of functions and function templates is formed comprising:
9781 // - For each constructor of the class template designated by the
9782 // template-name, a function template [...]
9783 // - For each deduction-guide, a function or function template [...]
9784 DeclarationNameInfo NameInfo(
9785 Context.DeclarationNames.getCXXDeductionGuideName(Template),
9786 TSInfo->getTypeLoc().getEndLoc());
9787 LookupResult Guides(*this, NameInfo, LookupOrdinaryName);
9788 LookupQualifiedName(Guides, Template->getDeclContext());
9789
9790 // FIXME: Do not diagnose inaccessible deduction guides. The standard isn't
9791 // clear on this, but they're not found by name so access does not apply.
9792 Guides.suppressDiagnostics();
9793
9794 // Figure out if this is list-initialization.
9795 InitListExpr *ListInit =
9796 (Inits.size() == 1 && Kind.getKind() != InitializationKind::IK_Direct)
9797 ? dyn_cast<InitListExpr>(Inits[0])
9798 : nullptr;
9799
9800 // C++1z [over.match.class.deduct]p1:
9801 // Initialization and overload resolution are performed as described in
9802 // [dcl.init] and [over.match.ctor], [over.match.copy], or [over.match.list]
9803 // (as appropriate for the type of initialization performed) for an object
9804 // of a hypothetical class type, where the selected functions and function
9805 // templates are considered to be the constructors of that class type
9806 //
9807 // Since we know we're initializing a class type of a type unrelated to that
9808 // of the initializer, this reduces to something fairly reasonable.
9809 OverloadCandidateSet Candidates(Kind.getLocation(),
9810 OverloadCandidateSet::CSK_Normal);
9811 OverloadCandidateSet::iterator Best;
9812
9813 bool HasAnyDeductionGuide = false;
9814 bool AllowExplicit = !Kind.isCopyInit() || ListInit;
9815
9816 auto tryToResolveOverload =
9817 [&](bool OnlyListConstructors) -> OverloadingResult {
9818 Candidates.clear(OverloadCandidateSet::CSK_Normal);
9819 HasAnyDeductionGuide = false;
9820
9821 for (auto I = Guides.begin(), E = Guides.end(); I != E; ++I) {
9822 NamedDecl *D = (*I)->getUnderlyingDecl();
9823 if (D->isInvalidDecl())
9824 continue;
9825
9826 auto *TD = dyn_cast<FunctionTemplateDecl>(D);
9827 auto *GD = dyn_cast_or_null<CXXDeductionGuideDecl>(
9828 TD ? TD->getTemplatedDecl() : dyn_cast<FunctionDecl>(D));
9829 if (!GD)
9830 continue;
9831
9832 if (!GD->isImplicit())
9833 HasAnyDeductionGuide = true;
9834
9835 // C++ [over.match.ctor]p1: (non-list copy-initialization from non-class)
9836 // For copy-initialization, the candidate functions are all the
9837 // converting constructors (12.3.1) of that class.
9838 // C++ [over.match.copy]p1: (non-list copy-initialization from class)
9839 // The converting constructors of T are candidate functions.
9840 if (!AllowExplicit) {
9841 // Overload resolution checks whether the deduction guide is declared
9842 // explicit for us.
9843
9844 // When looking for a converting constructor, deduction guides that
9845 // could never be called with one argument are not interesting to
9846 // check or note.
9847 if (GD->getMinRequiredArguments() > 1 ||
9848 (GD->getNumParams() == 0 && !GD->isVariadic()))
9849 continue;
9850 }
9851
9852 // C++ [over.match.list]p1.1: (first phase list initialization)
9853 // Initially, the candidate functions are the initializer-list
9854 // constructors of the class T
9855 if (OnlyListConstructors && !isInitListConstructor(GD))
9856 continue;
9857
9858 // C++ [over.match.list]p1.2: (second phase list initialization)
9859 // the candidate functions are all the constructors of the class T
9860 // C++ [over.match.ctor]p1: (all other cases)
9861 // the candidate functions are all the constructors of the class of
9862 // the object being initialized
9863
9864 // C++ [over.best.ics]p4:
9865 // When [...] the constructor [...] is a candidate by
9866 // - [over.match.copy] (in all cases)
9867 // FIXME: The "second phase of [over.match.list] case can also
9868 // theoretically happen here, but it's not clear whether we can
9869 // ever have a parameter of the right type.
9870 bool SuppressUserConversions = Kind.isCopyInit();
9871
9872 if (TD)
9873 AddTemplateOverloadCandidate(TD, I.getPair(), /*ExplicitArgs*/ nullptr,
9874 Inits, Candidates, SuppressUserConversions,
9875 /*PartialOverloading*/ false,
9876 AllowExplicit);
9877 else
9878 AddOverloadCandidate(GD, I.getPair(), Inits, Candidates,
9879 SuppressUserConversions,
9880 /*PartialOverloading*/ false, AllowExplicit);
9881 }
9882 return Candidates.BestViableFunction(*this, Kind.getLocation(), Best);
9883 };
9884
9885 OverloadingResult Result = OR_No_Viable_Function;
9886
9887 // C++11 [over.match.list]p1, per DR1467: for list-initialization, first
9888 // try initializer-list constructors.
9889 if (ListInit) {
9890 bool TryListConstructors = true;
9891
9892 // Try list constructors unless the list is empty and the class has one or
9893 // more default constructors, in which case those constructors win.
9894 if (!ListInit->getNumInits()) {
9895 for (NamedDecl *D : Guides) {
9896 auto *FD = dyn_cast<FunctionDecl>(D->getUnderlyingDecl());
9897 if (FD && FD->getMinRequiredArguments() == 0) {
9898 TryListConstructors = false;
9899 break;
9900 }
9901 }
9902 } else if (ListInit->getNumInits() == 1) {
9903 // C++ [over.match.class.deduct]:
9904 // As an exception, the first phase in [over.match.list] (considering
9905 // initializer-list constructors) is omitted if the initializer list
9906 // consists of a single expression of type cv U, where U is a
9907 // specialization of C or a class derived from a specialization of C.
9908 Expr *E = ListInit->getInit(0);
9909 auto *RD = E->getType()->getAsCXXRecordDecl();
9910 if (!isa<InitListExpr>(E) && RD &&
9911 isCompleteType(Kind.getLocation(), E->getType()) &&
9912 isOrIsDerivedFromSpecializationOf(RD, Template))
9913 TryListConstructors = false;
9914 }
9915
9916 if (TryListConstructors)
9917 Result = tryToResolveOverload(/*OnlyListConstructor*/true);
9918 // Then unwrap the initializer list and try again considering all
9919 // constructors.
9920 Inits = MultiExprArg(ListInit->getInits(), ListInit->getNumInits());
9921 }
9922
9923 // If list-initialization fails, or if we're doing any other kind of
9924 // initialization, we (eventually) consider constructors.
9925 if (Result == OR_No_Viable_Function)
9926 Result = tryToResolveOverload(/*OnlyListConstructor*/false);
9927
9928 switch (Result) {
9929 case OR_Ambiguous:
9930 // FIXME: For list-initialization candidates, it'd usually be better to
9931 // list why they were not viable when given the initializer list itself as
9932 // an argument.
9933 Candidates.NoteCandidates(
9934 PartialDiagnosticAt(
9935 Kind.getLocation(),
9936 PDiag(diag::err_deduced_class_template_ctor_ambiguous)
9937 << TemplateName),
9938 *this, OCD_AmbiguousCandidates, Inits);
9939 return QualType();
9940
9941 case OR_No_Viable_Function: {
9942 CXXRecordDecl *Primary =
9943 cast<ClassTemplateDecl>(Template)->getTemplatedDecl();
9944 bool Complete =
9945 isCompleteType(Kind.getLocation(), Context.getTypeDeclType(Primary));
9946 Candidates.NoteCandidates(
9947 PartialDiagnosticAt(
9948 Kind.getLocation(),
9949 PDiag(Complete ? diag::err_deduced_class_template_ctor_no_viable
9950 : diag::err_deduced_class_template_incomplete)
9951 << TemplateName << !Guides.empty()),
9952 *this, OCD_AllCandidates, Inits);
9953 return QualType();
9954 }
9955
9956 case OR_Deleted: {
9957 Diag(Kind.getLocation(), diag::err_deduced_class_template_deleted)
9958 << TemplateName;
9959 NoteDeletedFunction(Best->Function);
9960 return QualType();
9961 }
9962
9963 case OR_Success:
9964 // C++ [over.match.list]p1:
9965 // In copy-list-initialization, if an explicit constructor is chosen, the
9966 // initialization is ill-formed.
9967 if (Kind.isCopyInit() && ListInit &&
9968 cast<CXXDeductionGuideDecl>(Best->Function)->isExplicit()) {
9969 bool IsDeductionGuide = !Best->Function->isImplicit();
9970 Diag(Kind.getLocation(), diag::err_deduced_class_template_explicit)
9971 << TemplateName << IsDeductionGuide;
9972 Diag(Best->Function->getLocation(),
9973 diag::note_explicit_ctor_deduction_guide_here)
9974 << IsDeductionGuide;
9975 return QualType();
9976 }
9977
9978 // Make sure we didn't select an unusable deduction guide, and mark it
9979 // as referenced.
9980 DiagnoseUseOfDecl(Best->Function, Kind.getLocation());
9981 MarkFunctionReferenced(Kind.getLocation(), Best->Function);
9982 break;
9983 }
9984
9985 // C++ [dcl.type.class.deduct]p1:
9986 // The placeholder is replaced by the return type of the function selected
9987 // by overload resolution for class template deduction.
9988 QualType DeducedType =
9989 SubstAutoType(TSInfo->getType(), Best->Function->getReturnType());
9990 Diag(TSInfo->getTypeLoc().getBeginLoc(),
9991 diag::warn_cxx14_compat_class_template_argument_deduction)
9992 << TSInfo->getTypeLoc().getSourceRange() << 1 << DeducedType;
9993
9994 // Warn if CTAD was used on a type that does not have any user-defined
9995 // deduction guides.
9996 if (!HasAnyDeductionGuide) {
9997 Diag(TSInfo->getTypeLoc().getBeginLoc(),
9998 diag::warn_ctad_maybe_unsupported)
9999 << TemplateName;
10000 Diag(Template->getLocation(), diag::note_suppress_ctad_maybe_unsupported);
10001 }
10002
10003 return DeducedType;
10004 }
10005