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/Expr.h"
16 #include "clang/AST/ExprCXX.h"
17 #include "clang/AST/ExprObjC.h"
18 #include "clang/AST/ExprOpenMP.h"
19 #include "clang/AST/IgnoreExpr.h"
20 #include "clang/AST/TypeLoc.h"
21 #include "clang/Basic/CharInfo.h"
22 #include "clang/Basic/SourceManager.h"
23 #include "clang/Basic/Specifiers.h"
24 #include "clang/Basic/TargetInfo.h"
25 #include "clang/Sema/Designator.h"
26 #include "clang/Sema/EnterExpressionEvaluationContext.h"
27 #include "clang/Sema/Initialization.h"
28 #include "clang/Sema/Lookup.h"
29 #include "clang/Sema/Ownership.h"
30 #include "clang/Sema/SemaInternal.h"
31 #include "llvm/ADT/APInt.h"
32 #include "llvm/ADT/FoldingSet.h"
33 #include "llvm/ADT/PointerIntPair.h"
34 #include "llvm/ADT/SmallString.h"
35 #include "llvm/ADT/SmallVector.h"
36 #include "llvm/ADT/StringExtras.h"
37 #include "llvm/Support/ErrorHandling.h"
38 #include "llvm/Support/raw_ostream.h"
39
40 using namespace clang;
41
42 //===----------------------------------------------------------------------===//
43 // Sema Initialization Checking
44 //===----------------------------------------------------------------------===//
45
46 /// Check whether T is compatible with a wide character type (wchar_t,
47 /// char16_t or char32_t).
IsWideCharCompatible(QualType T,ASTContext & Context)48 static bool IsWideCharCompatible(QualType T, ASTContext &Context) {
49 if (Context.typesAreCompatible(Context.getWideCharType(), T))
50 return true;
51 if (Context.getLangOpts().CPlusPlus || Context.getLangOpts().C11) {
52 return Context.typesAreCompatible(Context.Char16Ty, T) ||
53 Context.typesAreCompatible(Context.Char32Ty, T);
54 }
55 return false;
56 }
57
58 enum StringInitFailureKind {
59 SIF_None,
60 SIF_NarrowStringIntoWideChar,
61 SIF_WideStringIntoChar,
62 SIF_IncompatWideStringIntoWideChar,
63 SIF_UTF8StringIntoPlainChar,
64 SIF_PlainStringIntoUTF8Char,
65 SIF_Other
66 };
67
68 /// Check whether the array of type AT can be initialized by the Init
69 /// expression by means of string initialization. Returns SIF_None if so,
70 /// otherwise returns a StringInitFailureKind that describes why the
71 /// initialization would not work.
IsStringInit(Expr * Init,const ArrayType * AT,ASTContext & Context)72 static StringInitFailureKind IsStringInit(Expr *Init, const ArrayType *AT,
73 ASTContext &Context) {
74 if (!isa<ConstantArrayType>(AT) && !isa<IncompleteArrayType>(AT))
75 return SIF_Other;
76
77 // See if this is a string literal or @encode.
78 Init = Init->IgnoreParens();
79
80 // Handle @encode, which is a narrow string.
81 if (isa<ObjCEncodeExpr>(Init) && AT->getElementType()->isCharType())
82 return SIF_None;
83
84 // Otherwise we can only handle string literals.
85 StringLiteral *SL = dyn_cast<StringLiteral>(Init);
86 if (!SL)
87 return SIF_Other;
88
89 const QualType ElemTy =
90 Context.getCanonicalType(AT->getElementType()).getUnqualifiedType();
91
92 auto IsCharOrUnsignedChar = [](const QualType &T) {
93 const BuiltinType *BT = dyn_cast<BuiltinType>(T.getTypePtr());
94 return BT && BT->isCharType() && BT->getKind() != BuiltinType::SChar;
95 };
96
97 switch (SL->getKind()) {
98 case StringLiteralKind::UTF8:
99 // char8_t array can be initialized with a UTF-8 string.
100 // - C++20 [dcl.init.string] (DR)
101 // Additionally, an array of char or unsigned char may be initialized
102 // by a UTF-8 string literal.
103 if (ElemTy->isChar8Type() ||
104 (Context.getLangOpts().Char8 &&
105 IsCharOrUnsignedChar(ElemTy.getCanonicalType())))
106 return SIF_None;
107 [[fallthrough]];
108 case StringLiteralKind::Ordinary:
109 // char array can be initialized with a narrow string.
110 // Only allow char x[] = "foo"; not char x[] = L"foo";
111 if (ElemTy->isCharType())
112 return (SL->getKind() == StringLiteralKind::UTF8 &&
113 Context.getLangOpts().Char8)
114 ? SIF_UTF8StringIntoPlainChar
115 : SIF_None;
116 if (ElemTy->isChar8Type())
117 return SIF_PlainStringIntoUTF8Char;
118 if (IsWideCharCompatible(ElemTy, Context))
119 return SIF_NarrowStringIntoWideChar;
120 return SIF_Other;
121 // C99 6.7.8p15 (with correction from DR343), or C11 6.7.9p15:
122 // "An array with element type compatible with a qualified or unqualified
123 // version of wchar_t, char16_t, or char32_t may be initialized by a wide
124 // string literal with the corresponding encoding prefix (L, u, or U,
125 // respectively), optionally enclosed in braces.
126 case StringLiteralKind::UTF16:
127 if (Context.typesAreCompatible(Context.Char16Ty, ElemTy))
128 return SIF_None;
129 if (ElemTy->isCharType() || ElemTy->isChar8Type())
130 return SIF_WideStringIntoChar;
131 if (IsWideCharCompatible(ElemTy, Context))
132 return SIF_IncompatWideStringIntoWideChar;
133 return SIF_Other;
134 case StringLiteralKind::UTF32:
135 if (Context.typesAreCompatible(Context.Char32Ty, ElemTy))
136 return SIF_None;
137 if (ElemTy->isCharType() || ElemTy->isChar8Type())
138 return SIF_WideStringIntoChar;
139 if (IsWideCharCompatible(ElemTy, Context))
140 return SIF_IncompatWideStringIntoWideChar;
141 return SIF_Other;
142 case StringLiteralKind::Wide:
143 if (Context.typesAreCompatible(Context.getWideCharType(), ElemTy))
144 return SIF_None;
145 if (ElemTy->isCharType() || ElemTy->isChar8Type())
146 return SIF_WideStringIntoChar;
147 if (IsWideCharCompatible(ElemTy, Context))
148 return SIF_IncompatWideStringIntoWideChar;
149 return SIF_Other;
150 case StringLiteralKind::Unevaluated:
151 assert(false && "Unevaluated string literal in initialization");
152 break;
153 }
154
155 llvm_unreachable("missed a StringLiteral kind?");
156 }
157
IsStringInit(Expr * init,QualType declType,ASTContext & Context)158 static StringInitFailureKind IsStringInit(Expr *init, QualType declType,
159 ASTContext &Context) {
160 const ArrayType *arrayType = Context.getAsArrayType(declType);
161 if (!arrayType)
162 return SIF_Other;
163 return IsStringInit(init, arrayType, Context);
164 }
165
IsStringInit(Expr * Init,const ArrayType * AT)166 bool Sema::IsStringInit(Expr *Init, const ArrayType *AT) {
167 return ::IsStringInit(Init, AT, Context) == SIF_None;
168 }
169
170 /// Update the type of a string literal, including any surrounding parentheses,
171 /// to match the type of the object which it is initializing.
updateStringLiteralType(Expr * E,QualType Ty)172 static void updateStringLiteralType(Expr *E, QualType Ty) {
173 while (true) {
174 E->setType(Ty);
175 E->setValueKind(VK_PRValue);
176 if (isa<StringLiteral>(E) || isa<ObjCEncodeExpr>(E))
177 break;
178 E = IgnoreParensSingleStep(E);
179 }
180 }
181
182 /// Fix a compound literal initializing an array so it's correctly marked
183 /// as an rvalue.
updateGNUCompoundLiteralRValue(Expr * E)184 static void updateGNUCompoundLiteralRValue(Expr *E) {
185 while (true) {
186 E->setValueKind(VK_PRValue);
187 if (isa<CompoundLiteralExpr>(E))
188 break;
189 E = IgnoreParensSingleStep(E);
190 }
191 }
192
CheckStringInit(Expr * Str,QualType & DeclT,const ArrayType * AT,Sema & S)193 static void CheckStringInit(Expr *Str, QualType &DeclT, const ArrayType *AT,
194 Sema &S) {
195 // Get the length of the string as parsed.
196 auto *ConstantArrayTy =
197 cast<ConstantArrayType>(Str->getType()->getAsArrayTypeUnsafe());
198 uint64_t StrLength = ConstantArrayTy->getSize().getZExtValue();
199
200 if (const IncompleteArrayType *IAT = dyn_cast<IncompleteArrayType>(AT)) {
201 // C99 6.7.8p14. We have an array of character type with unknown size
202 // being initialized to a string literal.
203 llvm::APInt ConstVal(32, StrLength);
204 // Return a new array type (C99 6.7.8p22).
205 DeclT = S.Context.getConstantArrayType(
206 IAT->getElementType(), ConstVal, nullptr, ArraySizeModifier::Normal, 0);
207 updateStringLiteralType(Str, DeclT);
208 return;
209 }
210
211 const ConstantArrayType *CAT = cast<ConstantArrayType>(AT);
212
213 // We have an array of character type with known size. However,
214 // the size may be smaller or larger than the string we are initializing.
215 // FIXME: Avoid truncation for 64-bit length strings.
216 if (S.getLangOpts().CPlusPlus) {
217 if (StringLiteral *SL = dyn_cast<StringLiteral>(Str->IgnoreParens())) {
218 // For Pascal strings it's OK to strip off the terminating null character,
219 // so the example below is valid:
220 //
221 // unsigned char a[2] = "\pa";
222 if (SL->isPascal())
223 StrLength--;
224 }
225
226 // [dcl.init.string]p2
227 if (StrLength > CAT->getSize().getZExtValue())
228 S.Diag(Str->getBeginLoc(),
229 diag::err_initializer_string_for_char_array_too_long)
230 << CAT->getSize().getZExtValue() << StrLength
231 << Str->getSourceRange();
232 } else {
233 // C99 6.7.8p14.
234 if (StrLength-1 > CAT->getSize().getZExtValue())
235 S.Diag(Str->getBeginLoc(),
236 diag::ext_initializer_string_for_char_array_too_long)
237 << Str->getSourceRange();
238 }
239
240 // Set the type to the actual size that we are initializing. If we have
241 // something like:
242 // char x[1] = "foo";
243 // then this will set the string literal's type to char[1].
244 updateStringLiteralType(Str, DeclT);
245 }
246
247 //===----------------------------------------------------------------------===//
248 // Semantic checking for initializer lists.
249 //===----------------------------------------------------------------------===//
250
251 namespace {
252
253 /// Semantic checking for initializer lists.
254 ///
255 /// The InitListChecker class contains a set of routines that each
256 /// handle the initialization of a certain kind of entity, e.g.,
257 /// arrays, vectors, struct/union types, scalars, etc. The
258 /// InitListChecker itself performs a recursive walk of the subobject
259 /// structure of the type to be initialized, while stepping through
260 /// the initializer list one element at a time. The IList and Index
261 /// parameters to each of the Check* routines contain the active
262 /// (syntactic) initializer list and the index into that initializer
263 /// list that represents the current initializer. Each routine is
264 /// responsible for moving that Index forward as it consumes elements.
265 ///
266 /// Each Check* routine also has a StructuredList/StructuredIndex
267 /// arguments, which contains the current "structured" (semantic)
268 /// initializer list and the index into that initializer list where we
269 /// are copying initializers as we map them over to the semantic
270 /// list. Once we have completed our recursive walk of the subobject
271 /// structure, we will have constructed a full semantic initializer
272 /// list.
273 ///
274 /// C99 designators cause changes in the initializer list traversal,
275 /// because they make the initialization "jump" into a specific
276 /// subobject and then continue the initialization from that
277 /// point. CheckDesignatedInitializer() recursively steps into the
278 /// designated subobject and manages backing out the recursion to
279 /// initialize the subobjects after the one designated.
280 ///
281 /// If an initializer list contains any designators, we build a placeholder
282 /// structured list even in 'verify only' mode, so that we can track which
283 /// elements need 'empty' initializtion.
284 class InitListChecker {
285 Sema &SemaRef;
286 bool hadError = false;
287 bool VerifyOnly; // No diagnostics.
288 bool TreatUnavailableAsInvalid; // Used only in VerifyOnly mode.
289 bool InOverloadResolution;
290 InitListExpr *FullyStructuredList = nullptr;
291 NoInitExpr *DummyExpr = nullptr;
292 SmallVectorImpl<QualType> *AggrDeductionCandidateParamTypes = nullptr;
293
getDummyInit()294 NoInitExpr *getDummyInit() {
295 if (!DummyExpr)
296 DummyExpr = new (SemaRef.Context) NoInitExpr(SemaRef.Context.VoidTy);
297 return DummyExpr;
298 }
299
300 void CheckImplicitInitList(const InitializedEntity &Entity,
301 InitListExpr *ParentIList, QualType T,
302 unsigned &Index, InitListExpr *StructuredList,
303 unsigned &StructuredIndex);
304 void CheckExplicitInitList(const InitializedEntity &Entity,
305 InitListExpr *IList, QualType &T,
306 InitListExpr *StructuredList,
307 bool TopLevelObject = false);
308 void CheckListElementTypes(const InitializedEntity &Entity,
309 InitListExpr *IList, QualType &DeclType,
310 bool SubobjectIsDesignatorContext,
311 unsigned &Index,
312 InitListExpr *StructuredList,
313 unsigned &StructuredIndex,
314 bool TopLevelObject = false);
315 void CheckSubElementType(const InitializedEntity &Entity,
316 InitListExpr *IList, QualType ElemType,
317 unsigned &Index,
318 InitListExpr *StructuredList,
319 unsigned &StructuredIndex,
320 bool DirectlyDesignated = false);
321 void CheckComplexType(const InitializedEntity &Entity,
322 InitListExpr *IList, QualType DeclType,
323 unsigned &Index,
324 InitListExpr *StructuredList,
325 unsigned &StructuredIndex);
326 void CheckScalarType(const InitializedEntity &Entity,
327 InitListExpr *IList, QualType DeclType,
328 unsigned &Index,
329 InitListExpr *StructuredList,
330 unsigned &StructuredIndex);
331 void CheckReferenceType(const InitializedEntity &Entity,
332 InitListExpr *IList, QualType DeclType,
333 unsigned &Index,
334 InitListExpr *StructuredList,
335 unsigned &StructuredIndex);
336 void CheckVectorType(const InitializedEntity &Entity,
337 InitListExpr *IList, QualType DeclType, unsigned &Index,
338 InitListExpr *StructuredList,
339 unsigned &StructuredIndex);
340 void CheckStructUnionTypes(const InitializedEntity &Entity,
341 InitListExpr *IList, QualType DeclType,
342 CXXRecordDecl::base_class_const_range Bases,
343 RecordDecl::field_iterator Field,
344 bool SubobjectIsDesignatorContext, unsigned &Index,
345 InitListExpr *StructuredList,
346 unsigned &StructuredIndex,
347 bool TopLevelObject = false);
348 void CheckArrayType(const InitializedEntity &Entity,
349 InitListExpr *IList, QualType &DeclType,
350 llvm::APSInt elementIndex,
351 bool SubobjectIsDesignatorContext, unsigned &Index,
352 InitListExpr *StructuredList,
353 unsigned &StructuredIndex);
354 bool CheckDesignatedInitializer(const InitializedEntity &Entity,
355 InitListExpr *IList, DesignatedInitExpr *DIE,
356 unsigned DesigIdx,
357 QualType &CurrentObjectType,
358 RecordDecl::field_iterator *NextField,
359 llvm::APSInt *NextElementIndex,
360 unsigned &Index,
361 InitListExpr *StructuredList,
362 unsigned &StructuredIndex,
363 bool FinishSubobjectInit,
364 bool TopLevelObject);
365 InitListExpr *getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
366 QualType CurrentObjectType,
367 InitListExpr *StructuredList,
368 unsigned StructuredIndex,
369 SourceRange InitRange,
370 bool IsFullyOverwritten = false);
371 void UpdateStructuredListElement(InitListExpr *StructuredList,
372 unsigned &StructuredIndex,
373 Expr *expr);
374 InitListExpr *createInitListExpr(QualType CurrentObjectType,
375 SourceRange InitRange,
376 unsigned ExpectedNumInits);
377 int numArrayElements(QualType DeclType);
378 int numStructUnionElements(QualType DeclType);
379 static RecordDecl *getRecordDecl(QualType DeclType);
380
381 ExprResult PerformEmptyInit(SourceLocation Loc,
382 const InitializedEntity &Entity);
383
384 /// Diagnose that OldInit (or part thereof) has been overridden by NewInit.
diagnoseInitOverride(Expr * OldInit,SourceRange NewInitRange,bool UnionOverride=false,bool FullyOverwritten=true)385 void diagnoseInitOverride(Expr *OldInit, SourceRange NewInitRange,
386 bool UnionOverride = false,
387 bool FullyOverwritten = true) {
388 // Overriding an initializer via a designator is valid with C99 designated
389 // initializers, but ill-formed with C++20 designated initializers.
390 unsigned DiagID =
391 SemaRef.getLangOpts().CPlusPlus
392 ? (UnionOverride ? diag::ext_initializer_union_overrides
393 : diag::ext_initializer_overrides)
394 : diag::warn_initializer_overrides;
395
396 if (InOverloadResolution && SemaRef.getLangOpts().CPlusPlus) {
397 // In overload resolution, we have to strictly enforce the rules, and so
398 // don't allow any overriding of prior initializers. This matters for a
399 // case such as:
400 //
401 // union U { int a, b; };
402 // struct S { int a, b; };
403 // void f(U), f(S);
404 //
405 // Here, f({.a = 1, .b = 2}) is required to call the struct overload. For
406 // consistency, we disallow all overriding of prior initializers in
407 // overload resolution, not only overriding of union members.
408 hadError = true;
409 } else if (OldInit->getType().isDestructedType() && !FullyOverwritten) {
410 // If we'll be keeping around the old initializer but overwriting part of
411 // the object it initialized, and that object is not trivially
412 // destructible, this can leak. Don't allow that, not even as an
413 // extension.
414 //
415 // FIXME: It might be reasonable to allow this in cases where the part of
416 // the initializer that we're overriding has trivial destruction.
417 DiagID = diag::err_initializer_overrides_destructed;
418 } else if (!OldInit->getSourceRange().isValid()) {
419 // We need to check on source range validity because the previous
420 // initializer does not have to be an explicit initializer. e.g.,
421 //
422 // struct P { int a, b; };
423 // struct PP { struct P p } l = { { .a = 2 }, .p.b = 3 };
424 //
425 // There is an overwrite taking place because the first braced initializer
426 // list "{ .a = 2 }" already provides value for .p.b (which is zero).
427 //
428 // Such overwrites are harmless, so we don't diagnose them. (Note that in
429 // C++, this cannot be reached unless we've already seen and diagnosed a
430 // different conformance issue, such as a mixture of designated and
431 // non-designated initializers or a multi-level designator.)
432 return;
433 }
434
435 if (!VerifyOnly) {
436 SemaRef.Diag(NewInitRange.getBegin(), DiagID)
437 << NewInitRange << FullyOverwritten << OldInit->getType();
438 SemaRef.Diag(OldInit->getBeginLoc(), diag::note_previous_initializer)
439 << (OldInit->HasSideEffects(SemaRef.Context) && FullyOverwritten)
440 << OldInit->getSourceRange();
441 }
442 }
443
444 // Explanation on the "FillWithNoInit" mode:
445 //
446 // Assume we have the following definitions (Case#1):
447 // struct P { char x[6][6]; } xp = { .x[1] = "bar" };
448 // struct PP { struct P lp; } l = { .lp = xp, .lp.x[1][2] = 'f' };
449 //
450 // l.lp.x[1][0..1] should not be filled with implicit initializers because the
451 // "base" initializer "xp" will provide values for them; l.lp.x[1] will be "baf".
452 //
453 // But if we have (Case#2):
454 // struct PP l = { .lp = xp, .lp.x[1] = { [2] = 'f' } };
455 //
456 // l.lp.x[1][0..1] are implicitly initialized and do not use values from the
457 // "base" initializer; l.lp.x[1] will be "\0\0f\0\0\0".
458 //
459 // To distinguish Case#1 from Case#2, and also to avoid leaving many "holes"
460 // in the InitListExpr, the "holes" in Case#1 are filled not with empty
461 // initializers but with special "NoInitExpr" place holders, which tells the
462 // CodeGen not to generate any initializers for these parts.
463 void FillInEmptyInitForBase(unsigned Init, const CXXBaseSpecifier &Base,
464 const InitializedEntity &ParentEntity,
465 InitListExpr *ILE, bool &RequiresSecondPass,
466 bool FillWithNoInit);
467 void FillInEmptyInitForField(unsigned Init, FieldDecl *Field,
468 const InitializedEntity &ParentEntity,
469 InitListExpr *ILE, bool &RequiresSecondPass,
470 bool FillWithNoInit = false);
471 void FillInEmptyInitializations(const InitializedEntity &Entity,
472 InitListExpr *ILE, bool &RequiresSecondPass,
473 InitListExpr *OuterILE, unsigned OuterIndex,
474 bool FillWithNoInit = false);
475 bool CheckFlexibleArrayInit(const InitializedEntity &Entity,
476 Expr *InitExpr, FieldDecl *Field,
477 bool TopLevelObject);
478 void CheckEmptyInitializable(const InitializedEntity &Entity,
479 SourceLocation Loc);
480
481 public:
482 InitListChecker(
483 Sema &S, const InitializedEntity &Entity, InitListExpr *IL, QualType &T,
484 bool VerifyOnly, bool TreatUnavailableAsInvalid,
485 bool InOverloadResolution = false,
486 SmallVectorImpl<QualType> *AggrDeductionCandidateParamTypes = nullptr);
InitListChecker(Sema & S,const InitializedEntity & Entity,InitListExpr * IL,QualType & T,SmallVectorImpl<QualType> & AggrDeductionCandidateParamTypes)487 InitListChecker(Sema &S, const InitializedEntity &Entity, InitListExpr *IL,
488 QualType &T,
489 SmallVectorImpl<QualType> &AggrDeductionCandidateParamTypes)
490 : InitListChecker(S, Entity, IL, T, /*VerifyOnly=*/true,
491 /*TreatUnavailableAsInvalid=*/false,
492 /*InOverloadResolution=*/false,
493 &AggrDeductionCandidateParamTypes){};
494
HadError()495 bool HadError() { return hadError; }
496
497 // Retrieves the fully-structured initializer list used for
498 // semantic analysis and code generation.
getFullyStructuredList() const499 InitListExpr *getFullyStructuredList() const { return FullyStructuredList; }
500 };
501
502 } // end anonymous namespace
503
PerformEmptyInit(SourceLocation Loc,const InitializedEntity & Entity)504 ExprResult InitListChecker::PerformEmptyInit(SourceLocation Loc,
505 const InitializedEntity &Entity) {
506 InitializationKind Kind = InitializationKind::CreateValue(Loc, Loc, Loc,
507 true);
508 MultiExprArg SubInit;
509 Expr *InitExpr;
510 InitListExpr DummyInitList(SemaRef.Context, Loc, std::nullopt, Loc);
511
512 // C++ [dcl.init.aggr]p7:
513 // If there are fewer initializer-clauses in the list than there are
514 // members in the aggregate, then each member not explicitly initialized
515 // ...
516 bool EmptyInitList = SemaRef.getLangOpts().CPlusPlus11 &&
517 Entity.getType()->getBaseElementTypeUnsafe()->isRecordType();
518 if (EmptyInitList) {
519 // C++1y / DR1070:
520 // shall be initialized [...] from an empty initializer list.
521 //
522 // We apply the resolution of this DR to C++11 but not C++98, since C++98
523 // does not have useful semantics for initialization from an init list.
524 // We treat this as copy-initialization, because aggregate initialization
525 // always performs copy-initialization on its elements.
526 //
527 // Only do this if we're initializing a class type, to avoid filling in
528 // the initializer list where possible.
529 InitExpr = VerifyOnly
530 ? &DummyInitList
531 : new (SemaRef.Context)
532 InitListExpr(SemaRef.Context, Loc, std::nullopt, Loc);
533 InitExpr->setType(SemaRef.Context.VoidTy);
534 SubInit = InitExpr;
535 Kind = InitializationKind::CreateCopy(Loc, Loc);
536 } else {
537 // C++03:
538 // shall be value-initialized.
539 }
540
541 InitializationSequence InitSeq(SemaRef, Entity, Kind, SubInit);
542 // libstdc++4.6 marks the vector default constructor as explicit in
543 // _GLIBCXX_DEBUG mode, so recover using the C++03 logic in that case.
544 // stlport does so too. Look for std::__debug for libstdc++, and for
545 // std:: for stlport. This is effectively a compiler-side implementation of
546 // LWG2193.
547 if (!InitSeq && EmptyInitList && InitSeq.getFailureKind() ==
548 InitializationSequence::FK_ExplicitConstructor) {
549 OverloadCandidateSet::iterator Best;
550 OverloadingResult O =
551 InitSeq.getFailedCandidateSet()
552 .BestViableFunction(SemaRef, Kind.getLocation(), Best);
553 (void)O;
554 assert(O == OR_Success && "Inconsistent overload resolution");
555 CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
556 CXXRecordDecl *R = CtorDecl->getParent();
557
558 if (CtorDecl->getMinRequiredArguments() == 0 &&
559 CtorDecl->isExplicit() && R->getDeclName() &&
560 SemaRef.SourceMgr.isInSystemHeader(CtorDecl->getLocation())) {
561 bool IsInStd = false;
562 for (NamespaceDecl *ND = dyn_cast<NamespaceDecl>(R->getDeclContext());
563 ND && !IsInStd; ND = dyn_cast<NamespaceDecl>(ND->getParent())) {
564 if (SemaRef.getStdNamespace()->InEnclosingNamespaceSetOf(ND))
565 IsInStd = true;
566 }
567
568 if (IsInStd && llvm::StringSwitch<bool>(R->getName())
569 .Cases("basic_string", "deque", "forward_list", true)
570 .Cases("list", "map", "multimap", "multiset", true)
571 .Cases("priority_queue", "queue", "set", "stack", true)
572 .Cases("unordered_map", "unordered_set", "vector", true)
573 .Default(false)) {
574 InitSeq.InitializeFrom(
575 SemaRef, Entity,
576 InitializationKind::CreateValue(Loc, Loc, Loc, true),
577 MultiExprArg(), /*TopLevelOfInitList=*/false,
578 TreatUnavailableAsInvalid);
579 // Emit a warning for this. System header warnings aren't shown
580 // by default, but people working on system headers should see it.
581 if (!VerifyOnly) {
582 SemaRef.Diag(CtorDecl->getLocation(),
583 diag::warn_invalid_initializer_from_system_header);
584 if (Entity.getKind() == InitializedEntity::EK_Member)
585 SemaRef.Diag(Entity.getDecl()->getLocation(),
586 diag::note_used_in_initialization_here);
587 else if (Entity.getKind() == InitializedEntity::EK_ArrayElement)
588 SemaRef.Diag(Loc, diag::note_used_in_initialization_here);
589 }
590 }
591 }
592 }
593 if (!InitSeq) {
594 if (!VerifyOnly) {
595 InitSeq.Diagnose(SemaRef, Entity, Kind, SubInit);
596 if (Entity.getKind() == InitializedEntity::EK_Member)
597 SemaRef.Diag(Entity.getDecl()->getLocation(),
598 diag::note_in_omitted_aggregate_initializer)
599 << /*field*/1 << Entity.getDecl();
600 else if (Entity.getKind() == InitializedEntity::EK_ArrayElement) {
601 bool IsTrailingArrayNewMember =
602 Entity.getParent() &&
603 Entity.getParent()->isVariableLengthArrayNew();
604 SemaRef.Diag(Loc, diag::note_in_omitted_aggregate_initializer)
605 << (IsTrailingArrayNewMember ? 2 : /*array element*/0)
606 << Entity.getElementIndex();
607 }
608 }
609 hadError = true;
610 return ExprError();
611 }
612
613 return VerifyOnly ? ExprResult()
614 : InitSeq.Perform(SemaRef, Entity, Kind, SubInit);
615 }
616
CheckEmptyInitializable(const InitializedEntity & Entity,SourceLocation Loc)617 void InitListChecker::CheckEmptyInitializable(const InitializedEntity &Entity,
618 SourceLocation Loc) {
619 // If we're building a fully-structured list, we'll check this at the end
620 // once we know which elements are actually initialized. Otherwise, we know
621 // that there are no designators so we can just check now.
622 if (FullyStructuredList)
623 return;
624 PerformEmptyInit(Loc, Entity);
625 }
626
FillInEmptyInitForBase(unsigned Init,const CXXBaseSpecifier & Base,const InitializedEntity & ParentEntity,InitListExpr * ILE,bool & RequiresSecondPass,bool FillWithNoInit)627 void InitListChecker::FillInEmptyInitForBase(
628 unsigned Init, const CXXBaseSpecifier &Base,
629 const InitializedEntity &ParentEntity, InitListExpr *ILE,
630 bool &RequiresSecondPass, bool FillWithNoInit) {
631 InitializedEntity BaseEntity = InitializedEntity::InitializeBase(
632 SemaRef.Context, &Base, false, &ParentEntity);
633
634 if (Init >= ILE->getNumInits() || !ILE->getInit(Init)) {
635 ExprResult BaseInit = FillWithNoInit
636 ? new (SemaRef.Context) NoInitExpr(Base.getType())
637 : PerformEmptyInit(ILE->getEndLoc(), BaseEntity);
638 if (BaseInit.isInvalid()) {
639 hadError = true;
640 return;
641 }
642
643 if (!VerifyOnly) {
644 assert(Init < ILE->getNumInits() && "should have been expanded");
645 ILE->setInit(Init, BaseInit.getAs<Expr>());
646 }
647 } else if (InitListExpr *InnerILE =
648 dyn_cast<InitListExpr>(ILE->getInit(Init))) {
649 FillInEmptyInitializations(BaseEntity, InnerILE, RequiresSecondPass,
650 ILE, Init, FillWithNoInit);
651 } else if (DesignatedInitUpdateExpr *InnerDIUE =
652 dyn_cast<DesignatedInitUpdateExpr>(ILE->getInit(Init))) {
653 FillInEmptyInitializations(BaseEntity, InnerDIUE->getUpdater(),
654 RequiresSecondPass, ILE, Init,
655 /*FillWithNoInit =*/true);
656 }
657 }
658
FillInEmptyInitForField(unsigned Init,FieldDecl * Field,const InitializedEntity & ParentEntity,InitListExpr * ILE,bool & RequiresSecondPass,bool FillWithNoInit)659 void InitListChecker::FillInEmptyInitForField(unsigned Init, FieldDecl *Field,
660 const InitializedEntity &ParentEntity,
661 InitListExpr *ILE,
662 bool &RequiresSecondPass,
663 bool FillWithNoInit) {
664 SourceLocation Loc = ILE->getEndLoc();
665 unsigned NumInits = ILE->getNumInits();
666 InitializedEntity MemberEntity
667 = InitializedEntity::InitializeMember(Field, &ParentEntity);
668
669 if (Init >= NumInits || !ILE->getInit(Init)) {
670 if (const RecordType *RType = ILE->getType()->getAs<RecordType>())
671 if (!RType->getDecl()->isUnion())
672 assert((Init < NumInits || VerifyOnly) &&
673 "This ILE should have been expanded");
674
675 if (FillWithNoInit) {
676 assert(!VerifyOnly && "should not fill with no-init in verify-only mode");
677 Expr *Filler = new (SemaRef.Context) NoInitExpr(Field->getType());
678 if (Init < NumInits)
679 ILE->setInit(Init, Filler);
680 else
681 ILE->updateInit(SemaRef.Context, Init, Filler);
682 return;
683 }
684 // C++1y [dcl.init.aggr]p7:
685 // If there are fewer initializer-clauses in the list than there are
686 // members in the aggregate, then each member not explicitly initialized
687 // shall be initialized from its brace-or-equal-initializer [...]
688 if (Field->hasInClassInitializer()) {
689 if (VerifyOnly)
690 return;
691
692 ExprResult DIE = SemaRef.BuildCXXDefaultInitExpr(Loc, Field);
693 if (DIE.isInvalid()) {
694 hadError = true;
695 return;
696 }
697 SemaRef.checkInitializerLifetime(MemberEntity, DIE.get());
698 if (Init < NumInits)
699 ILE->setInit(Init, DIE.get());
700 else {
701 ILE->updateInit(SemaRef.Context, Init, DIE.get());
702 RequiresSecondPass = true;
703 }
704 return;
705 }
706
707 if (Field->getType()->isReferenceType()) {
708 if (!VerifyOnly) {
709 // C++ [dcl.init.aggr]p9:
710 // If an incomplete or empty initializer-list leaves a
711 // member of reference type uninitialized, the program is
712 // ill-formed.
713 SemaRef.Diag(Loc, diag::err_init_reference_member_uninitialized)
714 << Field->getType()
715 << (ILE->isSyntacticForm() ? ILE : ILE->getSyntacticForm())
716 ->getSourceRange();
717 SemaRef.Diag(Field->getLocation(), diag::note_uninit_reference_member);
718 }
719 hadError = true;
720 return;
721 }
722
723 ExprResult MemberInit = PerformEmptyInit(Loc, MemberEntity);
724 if (MemberInit.isInvalid()) {
725 hadError = true;
726 return;
727 }
728
729 if (hadError || VerifyOnly) {
730 // Do nothing
731 } else if (Init < NumInits) {
732 ILE->setInit(Init, MemberInit.getAs<Expr>());
733 } else if (!isa<ImplicitValueInitExpr>(MemberInit.get())) {
734 // Empty initialization requires a constructor call, so
735 // extend the initializer list to include the constructor
736 // call and make a note that we'll need to take another pass
737 // through the initializer list.
738 ILE->updateInit(SemaRef.Context, Init, MemberInit.getAs<Expr>());
739 RequiresSecondPass = true;
740 }
741 } else if (InitListExpr *InnerILE
742 = dyn_cast<InitListExpr>(ILE->getInit(Init))) {
743 FillInEmptyInitializations(MemberEntity, InnerILE,
744 RequiresSecondPass, ILE, Init, FillWithNoInit);
745 } else if (DesignatedInitUpdateExpr *InnerDIUE =
746 dyn_cast<DesignatedInitUpdateExpr>(ILE->getInit(Init))) {
747 FillInEmptyInitializations(MemberEntity, InnerDIUE->getUpdater(),
748 RequiresSecondPass, ILE, Init,
749 /*FillWithNoInit =*/true);
750 }
751 }
752
753 /// Recursively replaces NULL values within the given initializer list
754 /// with expressions that perform value-initialization of the
755 /// appropriate type, and finish off the InitListExpr formation.
756 void
FillInEmptyInitializations(const InitializedEntity & Entity,InitListExpr * ILE,bool & RequiresSecondPass,InitListExpr * OuterILE,unsigned OuterIndex,bool FillWithNoInit)757 InitListChecker::FillInEmptyInitializations(const InitializedEntity &Entity,
758 InitListExpr *ILE,
759 bool &RequiresSecondPass,
760 InitListExpr *OuterILE,
761 unsigned OuterIndex,
762 bool FillWithNoInit) {
763 assert((ILE->getType() != SemaRef.Context.VoidTy) &&
764 "Should not have void type");
765
766 // We don't need to do any checks when just filling NoInitExprs; that can't
767 // fail.
768 if (FillWithNoInit && VerifyOnly)
769 return;
770
771 // If this is a nested initializer list, we might have changed its contents
772 // (and therefore some of its properties, such as instantiation-dependence)
773 // while filling it in. Inform the outer initializer list so that its state
774 // can be updated to match.
775 // FIXME: We should fully build the inner initializers before constructing
776 // the outer InitListExpr instead of mutating AST nodes after they have
777 // been used as subexpressions of other nodes.
778 struct UpdateOuterILEWithUpdatedInit {
779 InitListExpr *Outer;
780 unsigned OuterIndex;
781 ~UpdateOuterILEWithUpdatedInit() {
782 if (Outer)
783 Outer->setInit(OuterIndex, Outer->getInit(OuterIndex));
784 }
785 } UpdateOuterRAII = {OuterILE, OuterIndex};
786
787 // A transparent ILE is not performing aggregate initialization and should
788 // not be filled in.
789 if (ILE->isTransparent())
790 return;
791
792 if (const RecordType *RType = ILE->getType()->getAs<RecordType>()) {
793 const RecordDecl *RDecl = RType->getDecl();
794 if (RDecl->isUnion() && ILE->getInitializedFieldInUnion())
795 FillInEmptyInitForField(0, ILE->getInitializedFieldInUnion(),
796 Entity, ILE, RequiresSecondPass, FillWithNoInit);
797 else if (RDecl->isUnion() && isa<CXXRecordDecl>(RDecl) &&
798 cast<CXXRecordDecl>(RDecl)->hasInClassInitializer()) {
799 for (auto *Field : RDecl->fields()) {
800 if (Field->hasInClassInitializer()) {
801 FillInEmptyInitForField(0, Field, Entity, ILE, RequiresSecondPass,
802 FillWithNoInit);
803 break;
804 }
805 }
806 } else {
807 // The fields beyond ILE->getNumInits() are default initialized, so in
808 // order to leave them uninitialized, the ILE is expanded and the extra
809 // fields are then filled with NoInitExpr.
810 unsigned NumElems = numStructUnionElements(ILE->getType());
811 if (!RDecl->isUnion() && RDecl->hasFlexibleArrayMember())
812 ++NumElems;
813 if (!VerifyOnly && ILE->getNumInits() < NumElems)
814 ILE->resizeInits(SemaRef.Context, NumElems);
815
816 unsigned Init = 0;
817
818 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RDecl)) {
819 for (auto &Base : CXXRD->bases()) {
820 if (hadError)
821 return;
822
823 FillInEmptyInitForBase(Init, Base, Entity, ILE, RequiresSecondPass,
824 FillWithNoInit);
825 ++Init;
826 }
827 }
828
829 for (auto *Field : RDecl->fields()) {
830 if (Field->isUnnamedBitfield())
831 continue;
832
833 if (hadError)
834 return;
835
836 FillInEmptyInitForField(Init, Field, Entity, ILE, RequiresSecondPass,
837 FillWithNoInit);
838 if (hadError)
839 return;
840
841 ++Init;
842
843 // Only look at the first initialization of a union.
844 if (RDecl->isUnion())
845 break;
846 }
847 }
848
849 return;
850 }
851
852 QualType ElementType;
853
854 InitializedEntity ElementEntity = Entity;
855 unsigned NumInits = ILE->getNumInits();
856 unsigned NumElements = NumInits;
857 if (const ArrayType *AType = SemaRef.Context.getAsArrayType(ILE->getType())) {
858 ElementType = AType->getElementType();
859 if (const auto *CAType = dyn_cast<ConstantArrayType>(AType))
860 NumElements = CAType->getSize().getZExtValue();
861 // For an array new with an unknown bound, ask for one additional element
862 // in order to populate the array filler.
863 if (Entity.isVariableLengthArrayNew())
864 ++NumElements;
865 ElementEntity = InitializedEntity::InitializeElement(SemaRef.Context,
866 0, Entity);
867 } else if (const VectorType *VType = ILE->getType()->getAs<VectorType>()) {
868 ElementType = VType->getElementType();
869 NumElements = VType->getNumElements();
870 ElementEntity = InitializedEntity::InitializeElement(SemaRef.Context,
871 0, Entity);
872 } else
873 ElementType = ILE->getType();
874
875 bool SkipEmptyInitChecks = false;
876 for (unsigned Init = 0; Init != NumElements; ++Init) {
877 if (hadError)
878 return;
879
880 if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement ||
881 ElementEntity.getKind() == InitializedEntity::EK_VectorElement)
882 ElementEntity.setElementIndex(Init);
883
884 if (Init >= NumInits && (ILE->hasArrayFiller() || SkipEmptyInitChecks))
885 return;
886
887 Expr *InitExpr = (Init < NumInits ? ILE->getInit(Init) : nullptr);
888 if (!InitExpr && Init < NumInits && ILE->hasArrayFiller())
889 ILE->setInit(Init, ILE->getArrayFiller());
890 else if (!InitExpr && !ILE->hasArrayFiller()) {
891 // In VerifyOnly mode, there's no point performing empty initialization
892 // more than once.
893 if (SkipEmptyInitChecks)
894 continue;
895
896 Expr *Filler = nullptr;
897
898 if (FillWithNoInit)
899 Filler = new (SemaRef.Context) NoInitExpr(ElementType);
900 else {
901 ExprResult ElementInit =
902 PerformEmptyInit(ILE->getEndLoc(), ElementEntity);
903 if (ElementInit.isInvalid()) {
904 hadError = true;
905 return;
906 }
907
908 Filler = ElementInit.getAs<Expr>();
909 }
910
911 if (hadError) {
912 // Do nothing
913 } else if (VerifyOnly) {
914 SkipEmptyInitChecks = true;
915 } else if (Init < NumInits) {
916 // For arrays, just set the expression used for value-initialization
917 // of the "holes" in the array.
918 if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement)
919 ILE->setArrayFiller(Filler);
920 else
921 ILE->setInit(Init, Filler);
922 } else {
923 // For arrays, just set the expression used for value-initialization
924 // of the rest of elements and exit.
925 if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement) {
926 ILE->setArrayFiller(Filler);
927 return;
928 }
929
930 if (!isa<ImplicitValueInitExpr>(Filler) && !isa<NoInitExpr>(Filler)) {
931 // Empty initialization requires a constructor call, so
932 // extend the initializer list to include the constructor
933 // call and make a note that we'll need to take another pass
934 // through the initializer list.
935 ILE->updateInit(SemaRef.Context, Init, Filler);
936 RequiresSecondPass = true;
937 }
938 }
939 } else if (InitListExpr *InnerILE
940 = dyn_cast_or_null<InitListExpr>(InitExpr)) {
941 FillInEmptyInitializations(ElementEntity, InnerILE, RequiresSecondPass,
942 ILE, Init, FillWithNoInit);
943 } else if (DesignatedInitUpdateExpr *InnerDIUE =
944 dyn_cast_or_null<DesignatedInitUpdateExpr>(InitExpr)) {
945 FillInEmptyInitializations(ElementEntity, InnerDIUE->getUpdater(),
946 RequiresSecondPass, ILE, Init,
947 /*FillWithNoInit =*/true);
948 }
949 }
950 }
951
hasAnyDesignatedInits(const InitListExpr * IL)952 static bool hasAnyDesignatedInits(const InitListExpr *IL) {
953 for (const Stmt *Init : *IL)
954 if (isa_and_nonnull<DesignatedInitExpr>(Init))
955 return true;
956 return false;
957 }
958
InitListChecker(Sema & S,const InitializedEntity & Entity,InitListExpr * IL,QualType & T,bool VerifyOnly,bool TreatUnavailableAsInvalid,bool InOverloadResolution,SmallVectorImpl<QualType> * AggrDeductionCandidateParamTypes)959 InitListChecker::InitListChecker(
960 Sema &S, const InitializedEntity &Entity, InitListExpr *IL, QualType &T,
961 bool VerifyOnly, bool TreatUnavailableAsInvalid, bool InOverloadResolution,
962 SmallVectorImpl<QualType> *AggrDeductionCandidateParamTypes)
963 : SemaRef(S), VerifyOnly(VerifyOnly),
964 TreatUnavailableAsInvalid(TreatUnavailableAsInvalid),
965 InOverloadResolution(InOverloadResolution),
966 AggrDeductionCandidateParamTypes(AggrDeductionCandidateParamTypes) {
967 if (!VerifyOnly || hasAnyDesignatedInits(IL)) {
968 FullyStructuredList =
969 createInitListExpr(T, IL->getSourceRange(), IL->getNumInits());
970
971 // FIXME: Check that IL isn't already the semantic form of some other
972 // InitListExpr. If it is, we'd create a broken AST.
973 if (!VerifyOnly)
974 FullyStructuredList->setSyntacticForm(IL);
975 }
976
977 CheckExplicitInitList(Entity, IL, T, FullyStructuredList,
978 /*TopLevelObject=*/true);
979
980 if (!hadError && !AggrDeductionCandidateParamTypes && FullyStructuredList) {
981 bool RequiresSecondPass = false;
982 FillInEmptyInitializations(Entity, FullyStructuredList, RequiresSecondPass,
983 /*OuterILE=*/nullptr, /*OuterIndex=*/0);
984 if (RequiresSecondPass && !hadError)
985 FillInEmptyInitializations(Entity, FullyStructuredList,
986 RequiresSecondPass, nullptr, 0);
987 }
988 if (hadError && FullyStructuredList)
989 FullyStructuredList->markError();
990 }
991
numArrayElements(QualType DeclType)992 int InitListChecker::numArrayElements(QualType DeclType) {
993 // FIXME: use a proper constant
994 int maxElements = 0x7FFFFFFF;
995 if (const ConstantArrayType *CAT =
996 SemaRef.Context.getAsConstantArrayType(DeclType)) {
997 maxElements = static_cast<int>(CAT->getSize().getZExtValue());
998 }
999 return maxElements;
1000 }
1001
numStructUnionElements(QualType DeclType)1002 int InitListChecker::numStructUnionElements(QualType DeclType) {
1003 RecordDecl *structDecl = DeclType->castAs<RecordType>()->getDecl();
1004 int InitializableMembers = 0;
1005 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(structDecl))
1006 InitializableMembers += CXXRD->getNumBases();
1007 for (const auto *Field : structDecl->fields())
1008 if (!Field->isUnnamedBitfield())
1009 ++InitializableMembers;
1010
1011 if (structDecl->isUnion())
1012 return std::min(InitializableMembers, 1);
1013 return InitializableMembers - structDecl->hasFlexibleArrayMember();
1014 }
1015
getRecordDecl(QualType DeclType)1016 RecordDecl *InitListChecker::getRecordDecl(QualType DeclType) {
1017 if (const auto *RT = DeclType->getAs<RecordType>())
1018 return RT->getDecl();
1019 if (const auto *Inject = DeclType->getAs<InjectedClassNameType>())
1020 return Inject->getDecl();
1021 return nullptr;
1022 }
1023
1024 /// Determine whether Entity is an entity for which it is idiomatic to elide
1025 /// the braces in aggregate initialization.
isIdiomaticBraceElisionEntity(const InitializedEntity & Entity)1026 static bool isIdiomaticBraceElisionEntity(const InitializedEntity &Entity) {
1027 // Recursive initialization of the one and only field within an aggregate
1028 // class is considered idiomatic. This case arises in particular for
1029 // initialization of std::array, where the C++ standard suggests the idiom of
1030 //
1031 // std::array<T, N> arr = {1, 2, 3};
1032 //
1033 // (where std::array is an aggregate struct containing a single array field.
1034
1035 if (!Entity.getParent())
1036 return false;
1037
1038 // Allows elide brace initialization for aggregates with empty base.
1039 if (Entity.getKind() == InitializedEntity::EK_Base) {
1040 auto *ParentRD =
1041 Entity.getParent()->getType()->castAs<RecordType>()->getDecl();
1042 CXXRecordDecl *CXXRD = cast<CXXRecordDecl>(ParentRD);
1043 return CXXRD->getNumBases() == 1 && CXXRD->field_empty();
1044 }
1045
1046 // Allow brace elision if the only subobject is a field.
1047 if (Entity.getKind() == InitializedEntity::EK_Member) {
1048 auto *ParentRD =
1049 Entity.getParent()->getType()->castAs<RecordType>()->getDecl();
1050 if (CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(ParentRD)) {
1051 if (CXXRD->getNumBases()) {
1052 return false;
1053 }
1054 }
1055 auto FieldIt = ParentRD->field_begin();
1056 assert(FieldIt != ParentRD->field_end() &&
1057 "no fields but have initializer for member?");
1058 return ++FieldIt == ParentRD->field_end();
1059 }
1060
1061 return false;
1062 }
1063
1064 /// Check whether the range of the initializer \p ParentIList from element
1065 /// \p Index onwards can be used to initialize an object of type \p T. Update
1066 /// \p Index to indicate how many elements of the list were consumed.
1067 ///
1068 /// This also fills in \p StructuredList, from element \p StructuredIndex
1069 /// onwards, with the fully-braced, desugared form of the initialization.
CheckImplicitInitList(const InitializedEntity & Entity,InitListExpr * ParentIList,QualType T,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1070 void InitListChecker::CheckImplicitInitList(const InitializedEntity &Entity,
1071 InitListExpr *ParentIList,
1072 QualType T, unsigned &Index,
1073 InitListExpr *StructuredList,
1074 unsigned &StructuredIndex) {
1075 int maxElements = 0;
1076
1077 if (T->isArrayType())
1078 maxElements = numArrayElements(T);
1079 else if (T->isRecordType())
1080 maxElements = numStructUnionElements(T);
1081 else if (T->isVectorType())
1082 maxElements = T->castAs<VectorType>()->getNumElements();
1083 else
1084 llvm_unreachable("CheckImplicitInitList(): Illegal type");
1085
1086 if (maxElements == 0) {
1087 if (!VerifyOnly)
1088 SemaRef.Diag(ParentIList->getInit(Index)->getBeginLoc(),
1089 diag::err_implicit_empty_initializer);
1090 ++Index;
1091 hadError = true;
1092 return;
1093 }
1094
1095 // Build a structured initializer list corresponding to this subobject.
1096 InitListExpr *StructuredSubobjectInitList = getStructuredSubobjectInit(
1097 ParentIList, Index, T, StructuredList, StructuredIndex,
1098 SourceRange(ParentIList->getInit(Index)->getBeginLoc(),
1099 ParentIList->getSourceRange().getEnd()));
1100 unsigned StructuredSubobjectInitIndex = 0;
1101
1102 // Check the element types and build the structural subobject.
1103 unsigned StartIndex = Index;
1104 CheckListElementTypes(Entity, ParentIList, T,
1105 /*SubobjectIsDesignatorContext=*/false, Index,
1106 StructuredSubobjectInitList,
1107 StructuredSubobjectInitIndex);
1108
1109 if (StructuredSubobjectInitList) {
1110 StructuredSubobjectInitList->setType(T);
1111
1112 unsigned EndIndex = (Index == StartIndex? StartIndex : Index - 1);
1113 // Update the structured sub-object initializer so that it's ending
1114 // range corresponds with the end of the last initializer it used.
1115 if (EndIndex < ParentIList->getNumInits() &&
1116 ParentIList->getInit(EndIndex)) {
1117 SourceLocation EndLoc
1118 = ParentIList->getInit(EndIndex)->getSourceRange().getEnd();
1119 StructuredSubobjectInitList->setRBraceLoc(EndLoc);
1120 }
1121
1122 // Complain about missing braces.
1123 if (!VerifyOnly && (T->isArrayType() || T->isRecordType()) &&
1124 !ParentIList->isIdiomaticZeroInitializer(SemaRef.getLangOpts()) &&
1125 !isIdiomaticBraceElisionEntity(Entity)) {
1126 SemaRef.Diag(StructuredSubobjectInitList->getBeginLoc(),
1127 diag::warn_missing_braces)
1128 << StructuredSubobjectInitList->getSourceRange()
1129 << FixItHint::CreateInsertion(
1130 StructuredSubobjectInitList->getBeginLoc(), "{")
1131 << FixItHint::CreateInsertion(
1132 SemaRef.getLocForEndOfToken(
1133 StructuredSubobjectInitList->getEndLoc()),
1134 "}");
1135 }
1136
1137 // Warn if this type won't be an aggregate in future versions of C++.
1138 auto *CXXRD = T->getAsCXXRecordDecl();
1139 if (!VerifyOnly && CXXRD && CXXRD->hasUserDeclaredConstructor()) {
1140 SemaRef.Diag(StructuredSubobjectInitList->getBeginLoc(),
1141 diag::warn_cxx20_compat_aggregate_init_with_ctors)
1142 << StructuredSubobjectInitList->getSourceRange() << T;
1143 }
1144 }
1145 }
1146
1147 /// Warn that \p Entity was of scalar type and was initialized by a
1148 /// single-element braced initializer list.
warnBracedScalarInit(Sema & S,const InitializedEntity & Entity,SourceRange Braces)1149 static void warnBracedScalarInit(Sema &S, const InitializedEntity &Entity,
1150 SourceRange Braces) {
1151 // Don't warn during template instantiation. If the initialization was
1152 // non-dependent, we warned during the initial parse; otherwise, the
1153 // type might not be scalar in some uses of the template.
1154 if (S.inTemplateInstantiation())
1155 return;
1156
1157 unsigned DiagID = 0;
1158
1159 switch (Entity.getKind()) {
1160 case InitializedEntity::EK_VectorElement:
1161 case InitializedEntity::EK_ComplexElement:
1162 case InitializedEntity::EK_ArrayElement:
1163 case InitializedEntity::EK_Parameter:
1164 case InitializedEntity::EK_Parameter_CF_Audited:
1165 case InitializedEntity::EK_TemplateParameter:
1166 case InitializedEntity::EK_Result:
1167 case InitializedEntity::EK_ParenAggInitMember:
1168 // Extra braces here are suspicious.
1169 DiagID = diag::warn_braces_around_init;
1170 break;
1171
1172 case InitializedEntity::EK_Member:
1173 // Warn on aggregate initialization but not on ctor init list or
1174 // default member initializer.
1175 if (Entity.getParent())
1176 DiagID = diag::warn_braces_around_init;
1177 break;
1178
1179 case InitializedEntity::EK_Variable:
1180 case InitializedEntity::EK_LambdaCapture:
1181 // No warning, might be direct-list-initialization.
1182 // FIXME: Should we warn for copy-list-initialization in these cases?
1183 break;
1184
1185 case InitializedEntity::EK_New:
1186 case InitializedEntity::EK_Temporary:
1187 case InitializedEntity::EK_CompoundLiteralInit:
1188 // No warning, braces are part of the syntax of the underlying construct.
1189 break;
1190
1191 case InitializedEntity::EK_RelatedResult:
1192 // No warning, we already warned when initializing the result.
1193 break;
1194
1195 case InitializedEntity::EK_Exception:
1196 case InitializedEntity::EK_Base:
1197 case InitializedEntity::EK_Delegating:
1198 case InitializedEntity::EK_BlockElement:
1199 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
1200 case InitializedEntity::EK_Binding:
1201 case InitializedEntity::EK_StmtExprResult:
1202 llvm_unreachable("unexpected braced scalar init");
1203 }
1204
1205 if (DiagID) {
1206 S.Diag(Braces.getBegin(), DiagID)
1207 << Entity.getType()->isSizelessBuiltinType() << Braces
1208 << FixItHint::CreateRemoval(Braces.getBegin())
1209 << FixItHint::CreateRemoval(Braces.getEnd());
1210 }
1211 }
1212
1213 /// Check whether the initializer \p IList (that was written with explicit
1214 /// braces) can be used to initialize an object of type \p T.
1215 ///
1216 /// This also fills in \p StructuredList with the fully-braced, desugared
1217 /// form of the initialization.
CheckExplicitInitList(const InitializedEntity & Entity,InitListExpr * IList,QualType & T,InitListExpr * StructuredList,bool TopLevelObject)1218 void InitListChecker::CheckExplicitInitList(const InitializedEntity &Entity,
1219 InitListExpr *IList, QualType &T,
1220 InitListExpr *StructuredList,
1221 bool TopLevelObject) {
1222 unsigned Index = 0, StructuredIndex = 0;
1223 CheckListElementTypes(Entity, IList, T, /*SubobjectIsDesignatorContext=*/true,
1224 Index, StructuredList, StructuredIndex, TopLevelObject);
1225 if (StructuredList) {
1226 QualType ExprTy = T;
1227 if (!ExprTy->isArrayType())
1228 ExprTy = ExprTy.getNonLValueExprType(SemaRef.Context);
1229 if (!VerifyOnly)
1230 IList->setType(ExprTy);
1231 StructuredList->setType(ExprTy);
1232 }
1233 if (hadError)
1234 return;
1235
1236 // Don't complain for incomplete types, since we'll get an error elsewhere.
1237 if (Index < IList->getNumInits() && !T->isIncompleteType()) {
1238 // We have leftover initializers
1239 bool ExtraInitsIsError = SemaRef.getLangOpts().CPlusPlus ||
1240 (SemaRef.getLangOpts().OpenCL && T->isVectorType());
1241 hadError = ExtraInitsIsError;
1242 if (VerifyOnly) {
1243 return;
1244 } else if (StructuredIndex == 1 &&
1245 IsStringInit(StructuredList->getInit(0), T, SemaRef.Context) ==
1246 SIF_None) {
1247 unsigned DK =
1248 ExtraInitsIsError
1249 ? diag::err_excess_initializers_in_char_array_initializer
1250 : diag::ext_excess_initializers_in_char_array_initializer;
1251 SemaRef.Diag(IList->getInit(Index)->getBeginLoc(), DK)
1252 << IList->getInit(Index)->getSourceRange();
1253 } else if (T->isSizelessBuiltinType()) {
1254 unsigned DK = ExtraInitsIsError
1255 ? diag::err_excess_initializers_for_sizeless_type
1256 : diag::ext_excess_initializers_for_sizeless_type;
1257 SemaRef.Diag(IList->getInit(Index)->getBeginLoc(), DK)
1258 << T << IList->getInit(Index)->getSourceRange();
1259 } else {
1260 int initKind = T->isArrayType() ? 0 :
1261 T->isVectorType() ? 1 :
1262 T->isScalarType() ? 2 :
1263 T->isUnionType() ? 3 :
1264 4;
1265
1266 unsigned DK = ExtraInitsIsError ? diag::err_excess_initializers
1267 : diag::ext_excess_initializers;
1268 SemaRef.Diag(IList->getInit(Index)->getBeginLoc(), DK)
1269 << initKind << IList->getInit(Index)->getSourceRange();
1270 }
1271 }
1272
1273 if (!VerifyOnly) {
1274 if (T->isScalarType() && IList->getNumInits() == 1 &&
1275 !isa<InitListExpr>(IList->getInit(0)))
1276 warnBracedScalarInit(SemaRef, Entity, IList->getSourceRange());
1277
1278 // Warn if this is a class type that won't be an aggregate in future
1279 // versions of C++.
1280 auto *CXXRD = T->getAsCXXRecordDecl();
1281 if (CXXRD && CXXRD->hasUserDeclaredConstructor()) {
1282 // Don't warn if there's an equivalent default constructor that would be
1283 // used instead.
1284 bool HasEquivCtor = false;
1285 if (IList->getNumInits() == 0) {
1286 auto *CD = SemaRef.LookupDefaultConstructor(CXXRD);
1287 HasEquivCtor = CD && !CD->isDeleted();
1288 }
1289
1290 if (!HasEquivCtor) {
1291 SemaRef.Diag(IList->getBeginLoc(),
1292 diag::warn_cxx20_compat_aggregate_init_with_ctors)
1293 << IList->getSourceRange() << T;
1294 }
1295 }
1296 }
1297 }
1298
CheckListElementTypes(const InitializedEntity & Entity,InitListExpr * IList,QualType & DeclType,bool SubobjectIsDesignatorContext,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex,bool TopLevelObject)1299 void InitListChecker::CheckListElementTypes(const InitializedEntity &Entity,
1300 InitListExpr *IList,
1301 QualType &DeclType,
1302 bool SubobjectIsDesignatorContext,
1303 unsigned &Index,
1304 InitListExpr *StructuredList,
1305 unsigned &StructuredIndex,
1306 bool TopLevelObject) {
1307 if (DeclType->isAnyComplexType() && SubobjectIsDesignatorContext) {
1308 // Explicitly braced initializer for complex type can be real+imaginary
1309 // parts.
1310 CheckComplexType(Entity, IList, DeclType, Index,
1311 StructuredList, StructuredIndex);
1312 } else if (DeclType->isScalarType()) {
1313 CheckScalarType(Entity, IList, DeclType, Index,
1314 StructuredList, StructuredIndex);
1315 } else if (DeclType->isVectorType()) {
1316 CheckVectorType(Entity, IList, DeclType, Index,
1317 StructuredList, StructuredIndex);
1318 } else if (const RecordDecl *RD = getRecordDecl(DeclType)) {
1319 auto Bases =
1320 CXXRecordDecl::base_class_const_range(CXXRecordDecl::base_class_const_iterator(),
1321 CXXRecordDecl::base_class_const_iterator());
1322 if (DeclType->isRecordType()) {
1323 assert(DeclType->isAggregateType() &&
1324 "non-aggregate records should be handed in CheckSubElementType");
1325 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
1326 Bases = CXXRD->bases();
1327 } else {
1328 Bases = cast<CXXRecordDecl>(RD)->bases();
1329 }
1330 CheckStructUnionTypes(Entity, IList, DeclType, Bases, RD->field_begin(),
1331 SubobjectIsDesignatorContext, Index, StructuredList,
1332 StructuredIndex, TopLevelObject);
1333 } else if (DeclType->isArrayType()) {
1334 llvm::APSInt Zero(
1335 SemaRef.Context.getTypeSize(SemaRef.Context.getSizeType()),
1336 false);
1337 CheckArrayType(Entity, IList, DeclType, Zero,
1338 SubobjectIsDesignatorContext, Index,
1339 StructuredList, StructuredIndex);
1340 } else if (DeclType->isVoidType() || DeclType->isFunctionType()) {
1341 // This type is invalid, issue a diagnostic.
1342 ++Index;
1343 if (!VerifyOnly)
1344 SemaRef.Diag(IList->getBeginLoc(), diag::err_illegal_initializer_type)
1345 << DeclType;
1346 hadError = true;
1347 } else if (DeclType->isReferenceType()) {
1348 CheckReferenceType(Entity, IList, DeclType, Index,
1349 StructuredList, StructuredIndex);
1350 } else if (DeclType->isObjCObjectType()) {
1351 if (!VerifyOnly)
1352 SemaRef.Diag(IList->getBeginLoc(), diag::err_init_objc_class) << DeclType;
1353 hadError = true;
1354 } else if (DeclType->isOCLIntelSubgroupAVCType() ||
1355 DeclType->isSizelessBuiltinType()) {
1356 // Checks for scalar type are sufficient for these types too.
1357 CheckScalarType(Entity, IList, DeclType, Index, StructuredList,
1358 StructuredIndex);
1359 } else if (DeclType->isDependentType()) {
1360 // C++ [over.match.class.deduct]p1.5:
1361 // brace elision is not considered for any aggregate element that has a
1362 // dependent non-array type or an array type with a value-dependent bound
1363 ++Index;
1364 assert(AggrDeductionCandidateParamTypes);
1365 AggrDeductionCandidateParamTypes->push_back(DeclType);
1366 } else {
1367 if (!VerifyOnly)
1368 SemaRef.Diag(IList->getBeginLoc(), diag::err_illegal_initializer_type)
1369 << DeclType;
1370 hadError = true;
1371 }
1372 }
1373
CheckSubElementType(const InitializedEntity & Entity,InitListExpr * IList,QualType ElemType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex,bool DirectlyDesignated)1374 void InitListChecker::CheckSubElementType(const InitializedEntity &Entity,
1375 InitListExpr *IList,
1376 QualType ElemType,
1377 unsigned &Index,
1378 InitListExpr *StructuredList,
1379 unsigned &StructuredIndex,
1380 bool DirectlyDesignated) {
1381 Expr *expr = IList->getInit(Index);
1382
1383 if (ElemType->isReferenceType())
1384 return CheckReferenceType(Entity, IList, ElemType, Index,
1385 StructuredList, StructuredIndex);
1386
1387 if (InitListExpr *SubInitList = dyn_cast<InitListExpr>(expr)) {
1388 if (SubInitList->getNumInits() == 1 &&
1389 IsStringInit(SubInitList->getInit(0), ElemType, SemaRef.Context) ==
1390 SIF_None) {
1391 // FIXME: It would be more faithful and no less correct to include an
1392 // InitListExpr in the semantic form of the initializer list in this case.
1393 expr = SubInitList->getInit(0);
1394 }
1395 // Nested aggregate initialization and C++ initialization are handled later.
1396 } else if (isa<ImplicitValueInitExpr>(expr)) {
1397 // This happens during template instantiation when we see an InitListExpr
1398 // that we've already checked once.
1399 assert(SemaRef.Context.hasSameType(expr->getType(), ElemType) &&
1400 "found implicit initialization for the wrong type");
1401 UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
1402 ++Index;
1403 return;
1404 }
1405
1406 if (SemaRef.getLangOpts().CPlusPlus || isa<InitListExpr>(expr)) {
1407 // C++ [dcl.init.aggr]p2:
1408 // Each member is copy-initialized from the corresponding
1409 // initializer-clause.
1410
1411 // FIXME: Better EqualLoc?
1412 InitializationKind Kind =
1413 InitializationKind::CreateCopy(expr->getBeginLoc(), SourceLocation());
1414
1415 // Vector elements can be initialized from other vectors in which case
1416 // we need initialization entity with a type of a vector (and not a vector
1417 // element!) initializing multiple vector elements.
1418 auto TmpEntity =
1419 (ElemType->isExtVectorType() && !Entity.getType()->isExtVectorType())
1420 ? InitializedEntity::InitializeTemporary(ElemType)
1421 : Entity;
1422
1423 if (TmpEntity.getType()->isDependentType()) {
1424 // C++ [over.match.class.deduct]p1.5:
1425 // brace elision is not considered for any aggregate element that has a
1426 // dependent non-array type or an array type with a value-dependent
1427 // bound
1428 assert(AggrDeductionCandidateParamTypes);
1429 if (!isa_and_nonnull<ConstantArrayType>(
1430 SemaRef.Context.getAsArrayType(ElemType))) {
1431 ++Index;
1432 AggrDeductionCandidateParamTypes->push_back(ElemType);
1433 return;
1434 }
1435 } else {
1436 InitializationSequence Seq(SemaRef, TmpEntity, Kind, expr,
1437 /*TopLevelOfInitList*/ true);
1438 // C++14 [dcl.init.aggr]p13:
1439 // If the assignment-expression can initialize a member, the member is
1440 // initialized. Otherwise [...] brace elision is assumed
1441 //
1442 // Brace elision is never performed if the element is not an
1443 // assignment-expression.
1444 if (Seq || isa<InitListExpr>(expr)) {
1445 if (!VerifyOnly) {
1446 ExprResult Result = Seq.Perform(SemaRef, TmpEntity, Kind, expr);
1447 if (Result.isInvalid())
1448 hadError = true;
1449
1450 UpdateStructuredListElement(StructuredList, StructuredIndex,
1451 Result.getAs<Expr>());
1452 } else if (!Seq) {
1453 hadError = true;
1454 } else if (StructuredList) {
1455 UpdateStructuredListElement(StructuredList, StructuredIndex,
1456 getDummyInit());
1457 }
1458 ++Index;
1459 if (AggrDeductionCandidateParamTypes)
1460 AggrDeductionCandidateParamTypes->push_back(ElemType);
1461 return;
1462 }
1463 }
1464
1465 // Fall through for subaggregate initialization
1466 } else if (ElemType->isScalarType() || ElemType->isAtomicType()) {
1467 // FIXME: Need to handle atomic aggregate types with implicit init lists.
1468 return CheckScalarType(Entity, IList, ElemType, Index,
1469 StructuredList, StructuredIndex);
1470 } else if (const ArrayType *arrayType =
1471 SemaRef.Context.getAsArrayType(ElemType)) {
1472 // arrayType can be incomplete if we're initializing a flexible
1473 // array member. There's nothing we can do with the completed
1474 // type here, though.
1475
1476 if (IsStringInit(expr, arrayType, SemaRef.Context) == SIF_None) {
1477 // FIXME: Should we do this checking in verify-only mode?
1478 if (!VerifyOnly)
1479 CheckStringInit(expr, ElemType, arrayType, SemaRef);
1480 if (StructuredList)
1481 UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
1482 ++Index;
1483 return;
1484 }
1485
1486 // Fall through for subaggregate initialization.
1487
1488 } else {
1489 assert((ElemType->isRecordType() || ElemType->isVectorType() ||
1490 ElemType->isOpenCLSpecificType()) && "Unexpected type");
1491
1492 // C99 6.7.8p13:
1493 //
1494 // The initializer for a structure or union object that has
1495 // automatic storage duration shall be either an initializer
1496 // list as described below, or a single expression that has
1497 // compatible structure or union type. In the latter case, the
1498 // initial value of the object, including unnamed members, is
1499 // that of the expression.
1500 ExprResult ExprRes = expr;
1501 if (SemaRef.CheckSingleAssignmentConstraints(
1502 ElemType, ExprRes, !VerifyOnly) != Sema::Incompatible) {
1503 if (ExprRes.isInvalid())
1504 hadError = true;
1505 else {
1506 ExprRes = SemaRef.DefaultFunctionArrayLvalueConversion(ExprRes.get());
1507 if (ExprRes.isInvalid())
1508 hadError = true;
1509 }
1510 UpdateStructuredListElement(StructuredList, StructuredIndex,
1511 ExprRes.getAs<Expr>());
1512 ++Index;
1513 return;
1514 }
1515 ExprRes.get();
1516 // Fall through for subaggregate initialization
1517 }
1518
1519 // C++ [dcl.init.aggr]p12:
1520 //
1521 // [...] Otherwise, if the member is itself a non-empty
1522 // subaggregate, brace elision is assumed and the initializer is
1523 // considered for the initialization of the first member of
1524 // the subaggregate.
1525 // OpenCL vector initializer is handled elsewhere.
1526 if ((!SemaRef.getLangOpts().OpenCL && ElemType->isVectorType()) ||
1527 ElemType->isAggregateType()) {
1528 CheckImplicitInitList(Entity, IList, ElemType, Index, StructuredList,
1529 StructuredIndex);
1530 ++StructuredIndex;
1531
1532 // In C++20, brace elision is not permitted for a designated initializer.
1533 if (DirectlyDesignated && SemaRef.getLangOpts().CPlusPlus && !hadError) {
1534 if (InOverloadResolution)
1535 hadError = true;
1536 if (!VerifyOnly) {
1537 SemaRef.Diag(expr->getBeginLoc(),
1538 diag::ext_designated_init_brace_elision)
1539 << expr->getSourceRange()
1540 << FixItHint::CreateInsertion(expr->getBeginLoc(), "{")
1541 << FixItHint::CreateInsertion(
1542 SemaRef.getLocForEndOfToken(expr->getEndLoc()), "}");
1543 }
1544 }
1545 } else {
1546 if (!VerifyOnly) {
1547 // We cannot initialize this element, so let PerformCopyInitialization
1548 // produce the appropriate diagnostic. We already checked that this
1549 // initialization will fail.
1550 ExprResult Copy =
1551 SemaRef.PerformCopyInitialization(Entity, SourceLocation(), expr,
1552 /*TopLevelOfInitList=*/true);
1553 (void)Copy;
1554 assert(Copy.isInvalid() &&
1555 "expected non-aggregate initialization to fail");
1556 }
1557 hadError = true;
1558 ++Index;
1559 ++StructuredIndex;
1560 }
1561 }
1562
CheckComplexType(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1563 void InitListChecker::CheckComplexType(const InitializedEntity &Entity,
1564 InitListExpr *IList, QualType DeclType,
1565 unsigned &Index,
1566 InitListExpr *StructuredList,
1567 unsigned &StructuredIndex) {
1568 assert(Index == 0 && "Index in explicit init list must be zero");
1569
1570 // As an extension, clang supports complex initializers, which initialize
1571 // a complex number component-wise. When an explicit initializer list for
1572 // a complex number contains two initializers, this extension kicks in:
1573 // it expects the initializer list to contain two elements convertible to
1574 // the element type of the complex type. The first element initializes
1575 // the real part, and the second element intitializes the imaginary part.
1576
1577 if (IList->getNumInits() < 2)
1578 return CheckScalarType(Entity, IList, DeclType, Index, StructuredList,
1579 StructuredIndex);
1580
1581 // This is an extension in C. (The builtin _Complex type does not exist
1582 // in the C++ standard.)
1583 if (!SemaRef.getLangOpts().CPlusPlus && !VerifyOnly)
1584 SemaRef.Diag(IList->getBeginLoc(), diag::ext_complex_component_init)
1585 << IList->getSourceRange();
1586
1587 // Initialize the complex number.
1588 QualType elementType = DeclType->castAs<ComplexType>()->getElementType();
1589 InitializedEntity ElementEntity =
1590 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
1591
1592 for (unsigned i = 0; i < 2; ++i) {
1593 ElementEntity.setElementIndex(Index);
1594 CheckSubElementType(ElementEntity, IList, elementType, Index,
1595 StructuredList, StructuredIndex);
1596 }
1597 }
1598
CheckScalarType(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1599 void InitListChecker::CheckScalarType(const InitializedEntity &Entity,
1600 InitListExpr *IList, QualType DeclType,
1601 unsigned &Index,
1602 InitListExpr *StructuredList,
1603 unsigned &StructuredIndex) {
1604 if (Index >= IList->getNumInits()) {
1605 if (!VerifyOnly) {
1606 if (SemaRef.getLangOpts().CPlusPlus) {
1607 if (DeclType->isSizelessBuiltinType())
1608 SemaRef.Diag(IList->getBeginLoc(),
1609 SemaRef.getLangOpts().CPlusPlus11
1610 ? diag::warn_cxx98_compat_empty_sizeless_initializer
1611 : diag::err_empty_sizeless_initializer)
1612 << DeclType << IList->getSourceRange();
1613 else
1614 SemaRef.Diag(IList->getBeginLoc(),
1615 SemaRef.getLangOpts().CPlusPlus11
1616 ? diag::warn_cxx98_compat_empty_scalar_initializer
1617 : diag::err_empty_scalar_initializer)
1618 << IList->getSourceRange();
1619 }
1620 }
1621 hadError =
1622 SemaRef.getLangOpts().CPlusPlus && !SemaRef.getLangOpts().CPlusPlus11;
1623 ++Index;
1624 ++StructuredIndex;
1625 return;
1626 }
1627
1628 Expr *expr = IList->getInit(Index);
1629 if (InitListExpr *SubIList = dyn_cast<InitListExpr>(expr)) {
1630 // FIXME: This is invalid, and accepting it causes overload resolution
1631 // to pick the wrong overload in some corner cases.
1632 if (!VerifyOnly)
1633 SemaRef.Diag(SubIList->getBeginLoc(), diag::ext_many_braces_around_init)
1634 << DeclType->isSizelessBuiltinType() << SubIList->getSourceRange();
1635
1636 CheckScalarType(Entity, SubIList, DeclType, Index, StructuredList,
1637 StructuredIndex);
1638 return;
1639 } else if (isa<DesignatedInitExpr>(expr)) {
1640 if (!VerifyOnly)
1641 SemaRef.Diag(expr->getBeginLoc(),
1642 diag::err_designator_for_scalar_or_sizeless_init)
1643 << DeclType->isSizelessBuiltinType() << DeclType
1644 << expr->getSourceRange();
1645 hadError = true;
1646 ++Index;
1647 ++StructuredIndex;
1648 return;
1649 }
1650
1651 ExprResult Result;
1652 if (VerifyOnly) {
1653 if (SemaRef.CanPerformCopyInitialization(Entity, expr))
1654 Result = getDummyInit();
1655 else
1656 Result = ExprError();
1657 } else {
1658 Result =
1659 SemaRef.PerformCopyInitialization(Entity, expr->getBeginLoc(), expr,
1660 /*TopLevelOfInitList=*/true);
1661 }
1662
1663 Expr *ResultExpr = nullptr;
1664
1665 if (Result.isInvalid())
1666 hadError = true; // types weren't compatible.
1667 else {
1668 ResultExpr = Result.getAs<Expr>();
1669
1670 if (ResultExpr != expr && !VerifyOnly) {
1671 // The type was promoted, update initializer list.
1672 // FIXME: Why are we updating the syntactic init list?
1673 IList->setInit(Index, ResultExpr);
1674 }
1675 }
1676 UpdateStructuredListElement(StructuredList, StructuredIndex, ResultExpr);
1677 ++Index;
1678 if (AggrDeductionCandidateParamTypes)
1679 AggrDeductionCandidateParamTypes->push_back(DeclType);
1680 }
1681
CheckReferenceType(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1682 void InitListChecker::CheckReferenceType(const InitializedEntity &Entity,
1683 InitListExpr *IList, QualType DeclType,
1684 unsigned &Index,
1685 InitListExpr *StructuredList,
1686 unsigned &StructuredIndex) {
1687 if (Index >= IList->getNumInits()) {
1688 // FIXME: It would be wonderful if we could point at the actual member. In
1689 // general, it would be useful to pass location information down the stack,
1690 // so that we know the location (or decl) of the "current object" being
1691 // initialized.
1692 if (!VerifyOnly)
1693 SemaRef.Diag(IList->getBeginLoc(),
1694 diag::err_init_reference_member_uninitialized)
1695 << DeclType << IList->getSourceRange();
1696 hadError = true;
1697 ++Index;
1698 ++StructuredIndex;
1699 return;
1700 }
1701
1702 Expr *expr = IList->getInit(Index);
1703 if (isa<InitListExpr>(expr) && !SemaRef.getLangOpts().CPlusPlus11) {
1704 if (!VerifyOnly)
1705 SemaRef.Diag(IList->getBeginLoc(), diag::err_init_non_aggr_init_list)
1706 << DeclType << IList->getSourceRange();
1707 hadError = true;
1708 ++Index;
1709 ++StructuredIndex;
1710 return;
1711 }
1712
1713 ExprResult Result;
1714 if (VerifyOnly) {
1715 if (SemaRef.CanPerformCopyInitialization(Entity,expr))
1716 Result = getDummyInit();
1717 else
1718 Result = ExprError();
1719 } else {
1720 Result =
1721 SemaRef.PerformCopyInitialization(Entity, expr->getBeginLoc(), expr,
1722 /*TopLevelOfInitList=*/true);
1723 }
1724
1725 if (Result.isInvalid())
1726 hadError = true;
1727
1728 expr = Result.getAs<Expr>();
1729 // FIXME: Why are we updating the syntactic init list?
1730 if (!VerifyOnly && expr)
1731 IList->setInit(Index, expr);
1732
1733 UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
1734 ++Index;
1735 if (AggrDeductionCandidateParamTypes)
1736 AggrDeductionCandidateParamTypes->push_back(DeclType);
1737 }
1738
CheckVectorType(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1739 void InitListChecker::CheckVectorType(const InitializedEntity &Entity,
1740 InitListExpr *IList, QualType DeclType,
1741 unsigned &Index,
1742 InitListExpr *StructuredList,
1743 unsigned &StructuredIndex) {
1744 const VectorType *VT = DeclType->castAs<VectorType>();
1745 unsigned maxElements = VT->getNumElements();
1746 unsigned numEltsInit = 0;
1747 QualType elementType = VT->getElementType();
1748
1749 if (Index >= IList->getNumInits()) {
1750 // Make sure the element type can be value-initialized.
1751 CheckEmptyInitializable(
1752 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity),
1753 IList->getEndLoc());
1754 return;
1755 }
1756
1757 if (!SemaRef.getLangOpts().OpenCL && !SemaRef.getLangOpts().HLSL ) {
1758 // If the initializing element is a vector, try to copy-initialize
1759 // instead of breaking it apart (which is doomed to failure anyway).
1760 Expr *Init = IList->getInit(Index);
1761 if (!isa<InitListExpr>(Init) && Init->getType()->isVectorType()) {
1762 ExprResult Result;
1763 if (VerifyOnly) {
1764 if (SemaRef.CanPerformCopyInitialization(Entity, Init))
1765 Result = getDummyInit();
1766 else
1767 Result = ExprError();
1768 } else {
1769 Result =
1770 SemaRef.PerformCopyInitialization(Entity, Init->getBeginLoc(), Init,
1771 /*TopLevelOfInitList=*/true);
1772 }
1773
1774 Expr *ResultExpr = nullptr;
1775 if (Result.isInvalid())
1776 hadError = true; // types weren't compatible.
1777 else {
1778 ResultExpr = Result.getAs<Expr>();
1779
1780 if (ResultExpr != Init && !VerifyOnly) {
1781 // The type was promoted, update initializer list.
1782 // FIXME: Why are we updating the syntactic init list?
1783 IList->setInit(Index, ResultExpr);
1784 }
1785 }
1786 UpdateStructuredListElement(StructuredList, StructuredIndex, ResultExpr);
1787 ++Index;
1788 if (AggrDeductionCandidateParamTypes)
1789 AggrDeductionCandidateParamTypes->push_back(elementType);
1790 return;
1791 }
1792
1793 InitializedEntity ElementEntity =
1794 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
1795
1796 for (unsigned i = 0; i < maxElements; ++i, ++numEltsInit) {
1797 // Don't attempt to go past the end of the init list
1798 if (Index >= IList->getNumInits()) {
1799 CheckEmptyInitializable(ElementEntity, IList->getEndLoc());
1800 break;
1801 }
1802
1803 ElementEntity.setElementIndex(Index);
1804 CheckSubElementType(ElementEntity, IList, elementType, Index,
1805 StructuredList, StructuredIndex);
1806 }
1807
1808 if (VerifyOnly)
1809 return;
1810
1811 bool isBigEndian = SemaRef.Context.getTargetInfo().isBigEndian();
1812 const VectorType *T = Entity.getType()->castAs<VectorType>();
1813 if (isBigEndian && (T->getVectorKind() == VectorKind::Neon ||
1814 T->getVectorKind() == VectorKind::NeonPoly)) {
1815 // The ability to use vector initializer lists is a GNU vector extension
1816 // and is unrelated to the NEON intrinsics in arm_neon.h. On little
1817 // endian machines it works fine, however on big endian machines it
1818 // exhibits surprising behaviour:
1819 //
1820 // uint32x2_t x = {42, 64};
1821 // return vget_lane_u32(x, 0); // Will return 64.
1822 //
1823 // Because of this, explicitly call out that it is non-portable.
1824 //
1825 SemaRef.Diag(IList->getBeginLoc(),
1826 diag::warn_neon_vector_initializer_non_portable);
1827
1828 const char *typeCode;
1829 unsigned typeSize = SemaRef.Context.getTypeSize(elementType);
1830
1831 if (elementType->isFloatingType())
1832 typeCode = "f";
1833 else if (elementType->isSignedIntegerType())
1834 typeCode = "s";
1835 else if (elementType->isUnsignedIntegerType())
1836 typeCode = "u";
1837 else
1838 llvm_unreachable("Invalid element type!");
1839
1840 SemaRef.Diag(IList->getBeginLoc(),
1841 SemaRef.Context.getTypeSize(VT) > 64
1842 ? diag::note_neon_vector_initializer_non_portable_q
1843 : diag::note_neon_vector_initializer_non_portable)
1844 << typeCode << typeSize;
1845 }
1846
1847 return;
1848 }
1849
1850 InitializedEntity ElementEntity =
1851 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
1852
1853 // OpenCL and HLSL initializers allow vectors to be constructed from vectors.
1854 for (unsigned i = 0; i < maxElements; ++i) {
1855 // Don't attempt to go past the end of the init list
1856 if (Index >= IList->getNumInits())
1857 break;
1858
1859 ElementEntity.setElementIndex(Index);
1860
1861 QualType IType = IList->getInit(Index)->getType();
1862 if (!IType->isVectorType()) {
1863 CheckSubElementType(ElementEntity, IList, elementType, Index,
1864 StructuredList, StructuredIndex);
1865 ++numEltsInit;
1866 } else {
1867 QualType VecType;
1868 const VectorType *IVT = IType->castAs<VectorType>();
1869 unsigned numIElts = IVT->getNumElements();
1870
1871 if (IType->isExtVectorType())
1872 VecType = SemaRef.Context.getExtVectorType(elementType, numIElts);
1873 else
1874 VecType = SemaRef.Context.getVectorType(elementType, numIElts,
1875 IVT->getVectorKind());
1876 CheckSubElementType(ElementEntity, IList, VecType, Index,
1877 StructuredList, StructuredIndex);
1878 numEltsInit += numIElts;
1879 }
1880 }
1881
1882 // OpenCL and HLSL require all elements to be initialized.
1883 if (numEltsInit != maxElements) {
1884 if (!VerifyOnly)
1885 SemaRef.Diag(IList->getBeginLoc(),
1886 diag::err_vector_incorrect_num_initializers)
1887 << (numEltsInit < maxElements) << maxElements << numEltsInit;
1888 hadError = true;
1889 }
1890 }
1891
1892 /// Check if the type of a class element has an accessible destructor, and marks
1893 /// it referenced. Returns true if we shouldn't form a reference to the
1894 /// destructor.
1895 ///
1896 /// Aggregate initialization requires a class element's destructor be
1897 /// accessible per 11.6.1 [dcl.init.aggr]:
1898 ///
1899 /// The destructor for each element of class type is potentially invoked
1900 /// (15.4 [class.dtor]) from the context where the aggregate initialization
1901 /// occurs.
checkDestructorReference(QualType ElementType,SourceLocation Loc,Sema & SemaRef)1902 static bool checkDestructorReference(QualType ElementType, SourceLocation Loc,
1903 Sema &SemaRef) {
1904 auto *CXXRD = ElementType->getAsCXXRecordDecl();
1905 if (!CXXRD)
1906 return false;
1907
1908 CXXDestructorDecl *Destructor = SemaRef.LookupDestructor(CXXRD);
1909 SemaRef.CheckDestructorAccess(Loc, Destructor,
1910 SemaRef.PDiag(diag::err_access_dtor_temp)
1911 << ElementType);
1912 SemaRef.MarkFunctionReferenced(Loc, Destructor);
1913 return SemaRef.DiagnoseUseOfDecl(Destructor, Loc);
1914 }
1915
CheckArrayType(const InitializedEntity & Entity,InitListExpr * IList,QualType & DeclType,llvm::APSInt elementIndex,bool SubobjectIsDesignatorContext,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1916 void InitListChecker::CheckArrayType(const InitializedEntity &Entity,
1917 InitListExpr *IList, QualType &DeclType,
1918 llvm::APSInt elementIndex,
1919 bool SubobjectIsDesignatorContext,
1920 unsigned &Index,
1921 InitListExpr *StructuredList,
1922 unsigned &StructuredIndex) {
1923 const ArrayType *arrayType = SemaRef.Context.getAsArrayType(DeclType);
1924
1925 if (!VerifyOnly) {
1926 if (checkDestructorReference(arrayType->getElementType(),
1927 IList->getEndLoc(), SemaRef)) {
1928 hadError = true;
1929 return;
1930 }
1931 }
1932
1933 // Check for the special-case of initializing an array with a string.
1934 if (Index < IList->getNumInits()) {
1935 if (IsStringInit(IList->getInit(Index), arrayType, SemaRef.Context) ==
1936 SIF_None) {
1937 // We place the string literal directly into the resulting
1938 // initializer list. This is the only place where the structure
1939 // of the structured initializer list doesn't match exactly,
1940 // because doing so would involve allocating one character
1941 // constant for each string.
1942 // FIXME: Should we do these checks in verify-only mode too?
1943 if (!VerifyOnly)
1944 CheckStringInit(IList->getInit(Index), DeclType, arrayType, SemaRef);
1945 if (StructuredList) {
1946 UpdateStructuredListElement(StructuredList, StructuredIndex,
1947 IList->getInit(Index));
1948 StructuredList->resizeInits(SemaRef.Context, StructuredIndex);
1949 }
1950 ++Index;
1951 if (AggrDeductionCandidateParamTypes)
1952 AggrDeductionCandidateParamTypes->push_back(DeclType);
1953 return;
1954 }
1955 }
1956 if (const VariableArrayType *VAT = dyn_cast<VariableArrayType>(arrayType)) {
1957 // Check for VLAs; in standard C it would be possible to check this
1958 // earlier, but I don't know where clang accepts VLAs (gcc accepts
1959 // them in all sorts of strange places).
1960 bool HasErr = IList->getNumInits() != 0 || SemaRef.getLangOpts().CPlusPlus;
1961 if (!VerifyOnly) {
1962 // C23 6.7.10p4: An entity of variable length array type shall not be
1963 // initialized except by an empty initializer.
1964 //
1965 // The C extension warnings are issued from ParseBraceInitializer() and
1966 // do not need to be issued here. However, we continue to issue an error
1967 // in the case there are initializers or we are compiling C++. We allow
1968 // use of VLAs in C++, but it's not clear we want to allow {} to zero
1969 // init a VLA in C++ in all cases (such as with non-trivial constructors).
1970 // FIXME: should we allow this construct in C++ when it makes sense to do
1971 // so?
1972 if (HasErr)
1973 SemaRef.Diag(VAT->getSizeExpr()->getBeginLoc(),
1974 diag::err_variable_object_no_init)
1975 << VAT->getSizeExpr()->getSourceRange();
1976 }
1977 hadError = HasErr;
1978 ++Index;
1979 ++StructuredIndex;
1980 return;
1981 }
1982
1983 // We might know the maximum number of elements in advance.
1984 llvm::APSInt maxElements(elementIndex.getBitWidth(),
1985 elementIndex.isUnsigned());
1986 bool maxElementsKnown = false;
1987 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(arrayType)) {
1988 maxElements = CAT->getSize();
1989 elementIndex = elementIndex.extOrTrunc(maxElements.getBitWidth());
1990 elementIndex.setIsUnsigned(maxElements.isUnsigned());
1991 maxElementsKnown = true;
1992 }
1993
1994 QualType elementType = arrayType->getElementType();
1995 while (Index < IList->getNumInits()) {
1996 Expr *Init = IList->getInit(Index);
1997 if (DesignatedInitExpr *DIE = dyn_cast<DesignatedInitExpr>(Init)) {
1998 // If we're not the subobject that matches up with the '{' for
1999 // the designator, we shouldn't be handling the
2000 // designator. Return immediately.
2001 if (!SubobjectIsDesignatorContext)
2002 return;
2003
2004 // Handle this designated initializer. elementIndex will be
2005 // updated to be the next array element we'll initialize.
2006 if (CheckDesignatedInitializer(Entity, IList, DIE, 0,
2007 DeclType, nullptr, &elementIndex, Index,
2008 StructuredList, StructuredIndex, true,
2009 false)) {
2010 hadError = true;
2011 continue;
2012 }
2013
2014 if (elementIndex.getBitWidth() > maxElements.getBitWidth())
2015 maxElements = maxElements.extend(elementIndex.getBitWidth());
2016 else if (elementIndex.getBitWidth() < maxElements.getBitWidth())
2017 elementIndex = elementIndex.extend(maxElements.getBitWidth());
2018 elementIndex.setIsUnsigned(maxElements.isUnsigned());
2019
2020 // If the array is of incomplete type, keep track of the number of
2021 // elements in the initializer.
2022 if (!maxElementsKnown && elementIndex > maxElements)
2023 maxElements = elementIndex;
2024
2025 continue;
2026 }
2027
2028 // If we know the maximum number of elements, and we've already
2029 // hit it, stop consuming elements in the initializer list.
2030 if (maxElementsKnown && elementIndex == maxElements)
2031 break;
2032
2033 InitializedEntity ElementEntity =
2034 InitializedEntity::InitializeElement(SemaRef.Context, StructuredIndex,
2035 Entity);
2036 // Check this element.
2037 CheckSubElementType(ElementEntity, IList, elementType, Index,
2038 StructuredList, StructuredIndex);
2039 ++elementIndex;
2040
2041 // If the array is of incomplete type, keep track of the number of
2042 // elements in the initializer.
2043 if (!maxElementsKnown && elementIndex > maxElements)
2044 maxElements = elementIndex;
2045 }
2046 if (!hadError && DeclType->isIncompleteArrayType() && !VerifyOnly) {
2047 // If this is an incomplete array type, the actual type needs to
2048 // be calculated here.
2049 llvm::APSInt Zero(maxElements.getBitWidth(), maxElements.isUnsigned());
2050 if (maxElements == Zero && !Entity.isVariableLengthArrayNew()) {
2051 // Sizing an array implicitly to zero is not allowed by ISO C,
2052 // but is supported by GNU.
2053 SemaRef.Diag(IList->getBeginLoc(), diag::ext_typecheck_zero_array_size);
2054 }
2055
2056 DeclType = SemaRef.Context.getConstantArrayType(
2057 elementType, maxElements, nullptr, ArraySizeModifier::Normal, 0);
2058 }
2059 if (!hadError) {
2060 // If there are any members of the array that get value-initialized, check
2061 // that is possible. That happens if we know the bound and don't have
2062 // enough elements, or if we're performing an array new with an unknown
2063 // bound.
2064 if ((maxElementsKnown && elementIndex < maxElements) ||
2065 Entity.isVariableLengthArrayNew())
2066 CheckEmptyInitializable(
2067 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity),
2068 IList->getEndLoc());
2069 }
2070 }
2071
CheckFlexibleArrayInit(const InitializedEntity & Entity,Expr * InitExpr,FieldDecl * Field,bool TopLevelObject)2072 bool InitListChecker::CheckFlexibleArrayInit(const InitializedEntity &Entity,
2073 Expr *InitExpr,
2074 FieldDecl *Field,
2075 bool TopLevelObject) {
2076 // Handle GNU flexible array initializers.
2077 unsigned FlexArrayDiag;
2078 if (isa<InitListExpr>(InitExpr) &&
2079 cast<InitListExpr>(InitExpr)->getNumInits() == 0) {
2080 // Empty flexible array init always allowed as an extension
2081 FlexArrayDiag = diag::ext_flexible_array_init;
2082 } else if (!TopLevelObject) {
2083 // Disallow flexible array init on non-top-level object
2084 FlexArrayDiag = diag::err_flexible_array_init;
2085 } else if (Entity.getKind() != InitializedEntity::EK_Variable) {
2086 // Disallow flexible array init on anything which is not a variable.
2087 FlexArrayDiag = diag::err_flexible_array_init;
2088 } else if (cast<VarDecl>(Entity.getDecl())->hasLocalStorage()) {
2089 // Disallow flexible array init on local variables.
2090 FlexArrayDiag = diag::err_flexible_array_init;
2091 } else {
2092 // Allow other cases.
2093 FlexArrayDiag = diag::ext_flexible_array_init;
2094 }
2095
2096 if (!VerifyOnly) {
2097 SemaRef.Diag(InitExpr->getBeginLoc(), FlexArrayDiag)
2098 << InitExpr->getBeginLoc();
2099 SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
2100 << Field;
2101 }
2102
2103 return FlexArrayDiag != diag::ext_flexible_array_init;
2104 }
2105
CheckStructUnionTypes(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,CXXRecordDecl::base_class_const_range Bases,RecordDecl::field_iterator Field,bool SubobjectIsDesignatorContext,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex,bool TopLevelObject)2106 void InitListChecker::CheckStructUnionTypes(
2107 const InitializedEntity &Entity, InitListExpr *IList, QualType DeclType,
2108 CXXRecordDecl::base_class_const_range Bases, RecordDecl::field_iterator Field,
2109 bool SubobjectIsDesignatorContext, unsigned &Index,
2110 InitListExpr *StructuredList, unsigned &StructuredIndex,
2111 bool TopLevelObject) {
2112 const RecordDecl *RD = getRecordDecl(DeclType);
2113
2114 // If the record is invalid, some of it's members are invalid. To avoid
2115 // confusion, we forgo checking the initializer for the entire record.
2116 if (RD->isInvalidDecl()) {
2117 // Assume it was supposed to consume a single initializer.
2118 ++Index;
2119 hadError = true;
2120 return;
2121 }
2122
2123 if (RD->isUnion() && IList->getNumInits() == 0) {
2124 if (!VerifyOnly)
2125 for (FieldDecl *FD : RD->fields()) {
2126 QualType ET = SemaRef.Context.getBaseElementType(FD->getType());
2127 if (checkDestructorReference(ET, IList->getEndLoc(), SemaRef)) {
2128 hadError = true;
2129 return;
2130 }
2131 }
2132
2133 // If there's a default initializer, use it.
2134 if (isa<CXXRecordDecl>(RD) &&
2135 cast<CXXRecordDecl>(RD)->hasInClassInitializer()) {
2136 if (!StructuredList)
2137 return;
2138 for (RecordDecl::field_iterator FieldEnd = RD->field_end();
2139 Field != FieldEnd; ++Field) {
2140 if (Field->hasInClassInitializer()) {
2141 StructuredList->setInitializedFieldInUnion(*Field);
2142 // FIXME: Actually build a CXXDefaultInitExpr?
2143 return;
2144 }
2145 }
2146 }
2147
2148 // Value-initialize the first member of the union that isn't an unnamed
2149 // bitfield.
2150 for (RecordDecl::field_iterator FieldEnd = RD->field_end();
2151 Field != FieldEnd; ++Field) {
2152 if (!Field->isUnnamedBitfield()) {
2153 CheckEmptyInitializable(
2154 InitializedEntity::InitializeMember(*Field, &Entity),
2155 IList->getEndLoc());
2156 if (StructuredList)
2157 StructuredList->setInitializedFieldInUnion(*Field);
2158 break;
2159 }
2160 }
2161 return;
2162 }
2163
2164 bool InitializedSomething = false;
2165
2166 // If we have any base classes, they are initialized prior to the fields.
2167 for (auto I = Bases.begin(), E = Bases.end(); I != E; ++I) {
2168 auto &Base = *I;
2169 Expr *Init = Index < IList->getNumInits() ? IList->getInit(Index) : nullptr;
2170
2171 // Designated inits always initialize fields, so if we see one, all
2172 // remaining base classes have no explicit initializer.
2173 if (Init && isa<DesignatedInitExpr>(Init))
2174 Init = nullptr;
2175
2176 // C++ [over.match.class.deduct]p1.6:
2177 // each non-trailing aggregate element that is a pack expansion is assumed
2178 // to correspond to no elements of the initializer list, and (1.7) a
2179 // trailing aggregate element that is a pack expansion is assumed to
2180 // correspond to all remaining elements of the initializer list (if any).
2181
2182 // C++ [over.match.class.deduct]p1.9:
2183 // ... except that additional parameter packs of the form P_j... are
2184 // inserted into the parameter list in their original aggregate element
2185 // position corresponding to each non-trailing aggregate element of
2186 // type P_j that was skipped because it was a parameter pack, and the
2187 // trailing sequence of parameters corresponding to a trailing
2188 // aggregate element that is a pack expansion (if any) is replaced
2189 // by a single parameter of the form T_n....
2190 if (AggrDeductionCandidateParamTypes && Base.isPackExpansion()) {
2191 AggrDeductionCandidateParamTypes->push_back(
2192 SemaRef.Context.getPackExpansionType(Base.getType(), std::nullopt));
2193
2194 // Trailing pack expansion
2195 if (I + 1 == E && RD->field_empty()) {
2196 if (Index < IList->getNumInits())
2197 Index = IList->getNumInits();
2198 return;
2199 }
2200
2201 continue;
2202 }
2203
2204 SourceLocation InitLoc = Init ? Init->getBeginLoc() : IList->getEndLoc();
2205 InitializedEntity BaseEntity = InitializedEntity::InitializeBase(
2206 SemaRef.Context, &Base, false, &Entity);
2207 if (Init) {
2208 CheckSubElementType(BaseEntity, IList, Base.getType(), Index,
2209 StructuredList, StructuredIndex);
2210 InitializedSomething = true;
2211 } else {
2212 CheckEmptyInitializable(BaseEntity, InitLoc);
2213 }
2214
2215 if (!VerifyOnly)
2216 if (checkDestructorReference(Base.getType(), InitLoc, SemaRef)) {
2217 hadError = true;
2218 return;
2219 }
2220 }
2221
2222 // If structDecl is a forward declaration, this loop won't do
2223 // anything except look at designated initializers; That's okay,
2224 // because an error should get printed out elsewhere. It might be
2225 // worthwhile to skip over the rest of the initializer, though.
2226 RecordDecl::field_iterator FieldEnd = RD->field_end();
2227 size_t NumRecordDecls = llvm::count_if(RD->decls(), [&](const Decl *D) {
2228 return isa<FieldDecl>(D) || isa<RecordDecl>(D);
2229 });
2230 bool CheckForMissingFields =
2231 !IList->isIdiomaticZeroInitializer(SemaRef.getLangOpts());
2232 bool HasDesignatedInit = false;
2233
2234 llvm::SmallPtrSet<FieldDecl *, 4> InitializedFields;
2235
2236 while (Index < IList->getNumInits()) {
2237 Expr *Init = IList->getInit(Index);
2238 SourceLocation InitLoc = Init->getBeginLoc();
2239
2240 if (DesignatedInitExpr *DIE = dyn_cast<DesignatedInitExpr>(Init)) {
2241 // If we're not the subobject that matches up with the '{' for
2242 // the designator, we shouldn't be handling the
2243 // designator. Return immediately.
2244 if (!SubobjectIsDesignatorContext)
2245 return;
2246
2247 HasDesignatedInit = true;
2248
2249 // Handle this designated initializer. Field will be updated to
2250 // the next field that we'll be initializing.
2251 bool DesignatedInitFailed = CheckDesignatedInitializer(
2252 Entity, IList, DIE, 0, DeclType, &Field, nullptr, Index,
2253 StructuredList, StructuredIndex, true, TopLevelObject);
2254 if (DesignatedInitFailed)
2255 hadError = true;
2256
2257 // Find the field named by the designated initializer.
2258 DesignatedInitExpr::Designator *D = DIE->getDesignator(0);
2259 if (!VerifyOnly && D->isFieldDesignator()) {
2260 FieldDecl *F = D->getFieldDecl();
2261 InitializedFields.insert(F);
2262 if (!DesignatedInitFailed) {
2263 QualType ET = SemaRef.Context.getBaseElementType(F->getType());
2264 if (checkDestructorReference(ET, InitLoc, SemaRef)) {
2265 hadError = true;
2266 return;
2267 }
2268 }
2269 }
2270
2271 InitializedSomething = true;
2272
2273 // Disable check for missing fields when designators are used.
2274 // This matches gcc behaviour.
2275 if (!SemaRef.getLangOpts().CPlusPlus)
2276 CheckForMissingFields = false;
2277 continue;
2278 }
2279
2280 // Check if this is an initializer of forms:
2281 //
2282 // struct foo f = {};
2283 // struct foo g = {0};
2284 //
2285 // These are okay for randomized structures. [C99 6.7.8p19]
2286 //
2287 // Also, if there is only one element in the structure, we allow something
2288 // like this, because it's really not randomized in the tranditional sense.
2289 //
2290 // struct foo h = {bar};
2291 auto IsZeroInitializer = [&](const Expr *I) {
2292 if (IList->getNumInits() == 1) {
2293 if (NumRecordDecls == 1)
2294 return true;
2295 if (const auto *IL = dyn_cast<IntegerLiteral>(I))
2296 return IL->getValue().isZero();
2297 }
2298 return false;
2299 };
2300
2301 // Don't allow non-designated initializers on randomized structures.
2302 if (RD->isRandomized() && !IsZeroInitializer(Init)) {
2303 if (!VerifyOnly)
2304 SemaRef.Diag(InitLoc, diag::err_non_designated_init_used);
2305 hadError = true;
2306 break;
2307 }
2308
2309 if (Field == FieldEnd) {
2310 // We've run out of fields. We're done.
2311 break;
2312 }
2313
2314 // We've already initialized a member of a union. We're done.
2315 if (InitializedSomething && RD->isUnion())
2316 break;
2317
2318 // If we've hit the flexible array member at the end, we're done.
2319 if (Field->getType()->isIncompleteArrayType())
2320 break;
2321
2322 if (Field->isUnnamedBitfield()) {
2323 // Don't initialize unnamed bitfields, e.g. "int : 20;"
2324 ++Field;
2325 continue;
2326 }
2327
2328 // Make sure we can use this declaration.
2329 bool InvalidUse;
2330 if (VerifyOnly)
2331 InvalidUse = !SemaRef.CanUseDecl(*Field, TreatUnavailableAsInvalid);
2332 else
2333 InvalidUse = SemaRef.DiagnoseUseOfDecl(
2334 *Field, IList->getInit(Index)->getBeginLoc());
2335 if (InvalidUse) {
2336 ++Index;
2337 ++Field;
2338 hadError = true;
2339 continue;
2340 }
2341
2342 if (!VerifyOnly) {
2343 QualType ET = SemaRef.Context.getBaseElementType(Field->getType());
2344 if (checkDestructorReference(ET, InitLoc, SemaRef)) {
2345 hadError = true;
2346 return;
2347 }
2348 }
2349
2350 InitializedEntity MemberEntity =
2351 InitializedEntity::InitializeMember(*Field, &Entity);
2352 CheckSubElementType(MemberEntity, IList, Field->getType(), Index,
2353 StructuredList, StructuredIndex);
2354 InitializedSomething = true;
2355 InitializedFields.insert(*Field);
2356
2357 if (RD->isUnion() && StructuredList) {
2358 // Initialize the first field within the union.
2359 StructuredList->setInitializedFieldInUnion(*Field);
2360 }
2361
2362 ++Field;
2363 }
2364
2365 // Emit warnings for missing struct field initializers.
2366 if (!VerifyOnly && InitializedSomething && CheckForMissingFields &&
2367 !RD->isUnion()) {
2368 // It is possible we have one or more unnamed bitfields remaining.
2369 // Find first (if any) named field and emit warning.
2370 for (RecordDecl::field_iterator it = HasDesignatedInit ? RD->field_begin()
2371 : Field,
2372 end = RD->field_end();
2373 it != end; ++it) {
2374 if (HasDesignatedInit && InitializedFields.count(*it))
2375 continue;
2376
2377 if (!it->isUnnamedBitfield() && !it->hasInClassInitializer() &&
2378 !it->getType()->isIncompleteArrayType()) {
2379 SemaRef.Diag(IList->getSourceRange().getEnd(),
2380 diag::warn_missing_field_initializers)
2381 << *it;
2382 break;
2383 }
2384 }
2385 }
2386
2387 // Check that any remaining fields can be value-initialized if we're not
2388 // building a structured list. (If we are, we'll check this later.)
2389 if (!StructuredList && Field != FieldEnd && !RD->isUnion() &&
2390 !Field->getType()->isIncompleteArrayType()) {
2391 for (; Field != FieldEnd && !hadError; ++Field) {
2392 if (!Field->isUnnamedBitfield() && !Field->hasInClassInitializer())
2393 CheckEmptyInitializable(
2394 InitializedEntity::InitializeMember(*Field, &Entity),
2395 IList->getEndLoc());
2396 }
2397 }
2398
2399 // Check that the types of the remaining fields have accessible destructors.
2400 if (!VerifyOnly) {
2401 // If the initializer expression has a designated initializer, check the
2402 // elements for which a designated initializer is not provided too.
2403 RecordDecl::field_iterator I = HasDesignatedInit ? RD->field_begin()
2404 : Field;
2405 for (RecordDecl::field_iterator E = RD->field_end(); I != E; ++I) {
2406 QualType ET = SemaRef.Context.getBaseElementType(I->getType());
2407 if (checkDestructorReference(ET, IList->getEndLoc(), SemaRef)) {
2408 hadError = true;
2409 return;
2410 }
2411 }
2412 }
2413
2414 if (Field == FieldEnd || !Field->getType()->isIncompleteArrayType() ||
2415 Index >= IList->getNumInits())
2416 return;
2417
2418 if (CheckFlexibleArrayInit(Entity, IList->getInit(Index), *Field,
2419 TopLevelObject)) {
2420 hadError = true;
2421 ++Index;
2422 return;
2423 }
2424
2425 InitializedEntity MemberEntity =
2426 InitializedEntity::InitializeMember(*Field, &Entity);
2427
2428 if (isa<InitListExpr>(IList->getInit(Index)) ||
2429 AggrDeductionCandidateParamTypes)
2430 CheckSubElementType(MemberEntity, IList, Field->getType(), Index,
2431 StructuredList, StructuredIndex);
2432 else
2433 CheckImplicitInitList(MemberEntity, IList, Field->getType(), Index,
2434 StructuredList, StructuredIndex);
2435 }
2436
2437 /// Expand a field designator that refers to a member of an
2438 /// anonymous struct or union into a series of field designators that
2439 /// refers to the field within the appropriate subobject.
2440 ///
ExpandAnonymousFieldDesignator(Sema & SemaRef,DesignatedInitExpr * DIE,unsigned DesigIdx,IndirectFieldDecl * IndirectField)2441 static void ExpandAnonymousFieldDesignator(Sema &SemaRef,
2442 DesignatedInitExpr *DIE,
2443 unsigned DesigIdx,
2444 IndirectFieldDecl *IndirectField) {
2445 typedef DesignatedInitExpr::Designator Designator;
2446
2447 // Build the replacement designators.
2448 SmallVector<Designator, 4> Replacements;
2449 for (IndirectFieldDecl::chain_iterator PI = IndirectField->chain_begin(),
2450 PE = IndirectField->chain_end(); PI != PE; ++PI) {
2451 if (PI + 1 == PE)
2452 Replacements.push_back(Designator::CreateFieldDesignator(
2453 (IdentifierInfo *)nullptr, DIE->getDesignator(DesigIdx)->getDotLoc(),
2454 DIE->getDesignator(DesigIdx)->getFieldLoc()));
2455 else
2456 Replacements.push_back(Designator::CreateFieldDesignator(
2457 (IdentifierInfo *)nullptr, SourceLocation(), SourceLocation()));
2458 assert(isa<FieldDecl>(*PI));
2459 Replacements.back().setFieldDecl(cast<FieldDecl>(*PI));
2460 }
2461
2462 // Expand the current designator into the set of replacement
2463 // designators, so we have a full subobject path down to where the
2464 // member of the anonymous struct/union is actually stored.
2465 DIE->ExpandDesignator(SemaRef.Context, DesigIdx, &Replacements[0],
2466 &Replacements[0] + Replacements.size());
2467 }
2468
CloneDesignatedInitExpr(Sema & SemaRef,DesignatedInitExpr * DIE)2469 static DesignatedInitExpr *CloneDesignatedInitExpr(Sema &SemaRef,
2470 DesignatedInitExpr *DIE) {
2471 unsigned NumIndexExprs = DIE->getNumSubExprs() - 1;
2472 SmallVector<Expr*, 4> IndexExprs(NumIndexExprs);
2473 for (unsigned I = 0; I < NumIndexExprs; ++I)
2474 IndexExprs[I] = DIE->getSubExpr(I + 1);
2475 return DesignatedInitExpr::Create(SemaRef.Context, DIE->designators(),
2476 IndexExprs,
2477 DIE->getEqualOrColonLoc(),
2478 DIE->usesGNUSyntax(), DIE->getInit());
2479 }
2480
2481 namespace {
2482
2483 // Callback to only accept typo corrections that are for field members of
2484 // the given struct or union.
2485 class FieldInitializerValidatorCCC final : public CorrectionCandidateCallback {
2486 public:
FieldInitializerValidatorCCC(const RecordDecl * RD)2487 explicit FieldInitializerValidatorCCC(const RecordDecl *RD)
2488 : Record(RD) {}
2489
ValidateCandidate(const TypoCorrection & candidate)2490 bool ValidateCandidate(const TypoCorrection &candidate) override {
2491 FieldDecl *FD = candidate.getCorrectionDeclAs<FieldDecl>();
2492 return FD && FD->getDeclContext()->getRedeclContext()->Equals(Record);
2493 }
2494
clone()2495 std::unique_ptr<CorrectionCandidateCallback> clone() override {
2496 return std::make_unique<FieldInitializerValidatorCCC>(*this);
2497 }
2498
2499 private:
2500 const RecordDecl *Record;
2501 };
2502
2503 } // end anonymous namespace
2504
2505 /// Check the well-formedness of a C99 designated initializer.
2506 ///
2507 /// Determines whether the designated initializer @p DIE, which
2508 /// resides at the given @p Index within the initializer list @p
2509 /// IList, is well-formed for a current object of type @p DeclType
2510 /// (C99 6.7.8). The actual subobject that this designator refers to
2511 /// within the current subobject is returned in either
2512 /// @p NextField or @p NextElementIndex (whichever is appropriate).
2513 ///
2514 /// @param IList The initializer list in which this designated
2515 /// initializer occurs.
2516 ///
2517 /// @param DIE The designated initializer expression.
2518 ///
2519 /// @param DesigIdx The index of the current designator.
2520 ///
2521 /// @param CurrentObjectType The type of the "current object" (C99 6.7.8p17),
2522 /// into which the designation in @p DIE should refer.
2523 ///
2524 /// @param NextField If non-NULL and the first designator in @p DIE is
2525 /// a field, this will be set to the field declaration corresponding
2526 /// to the field named by the designator. On input, this is expected to be
2527 /// the next field that would be initialized in the absence of designation,
2528 /// if the complete object being initialized is a struct.
2529 ///
2530 /// @param NextElementIndex If non-NULL and the first designator in @p
2531 /// DIE is an array designator or GNU array-range designator, this
2532 /// will be set to the last index initialized by this designator.
2533 ///
2534 /// @param Index Index into @p IList where the designated initializer
2535 /// @p DIE occurs.
2536 ///
2537 /// @param StructuredList The initializer list expression that
2538 /// describes all of the subobject initializers in the order they'll
2539 /// actually be initialized.
2540 ///
2541 /// @returns true if there was an error, false otherwise.
2542 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)2543 InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity,
2544 InitListExpr *IList,
2545 DesignatedInitExpr *DIE,
2546 unsigned DesigIdx,
2547 QualType &CurrentObjectType,
2548 RecordDecl::field_iterator *NextField,
2549 llvm::APSInt *NextElementIndex,
2550 unsigned &Index,
2551 InitListExpr *StructuredList,
2552 unsigned &StructuredIndex,
2553 bool FinishSubobjectInit,
2554 bool TopLevelObject) {
2555 if (DesigIdx == DIE->size()) {
2556 // C++20 designated initialization can result in direct-list-initialization
2557 // of the designated subobject. This is the only way that we can end up
2558 // performing direct initialization as part of aggregate initialization, so
2559 // it needs special handling.
2560 if (DIE->isDirectInit()) {
2561 Expr *Init = DIE->getInit();
2562 assert(isa<InitListExpr>(Init) &&
2563 "designator result in direct non-list initialization?");
2564 InitializationKind Kind = InitializationKind::CreateDirectList(
2565 DIE->getBeginLoc(), Init->getBeginLoc(), Init->getEndLoc());
2566 InitializationSequence Seq(SemaRef, Entity, Kind, Init,
2567 /*TopLevelOfInitList*/ true);
2568 if (StructuredList) {
2569 ExprResult Result = VerifyOnly
2570 ? getDummyInit()
2571 : Seq.Perform(SemaRef, Entity, Kind, Init);
2572 UpdateStructuredListElement(StructuredList, StructuredIndex,
2573 Result.get());
2574 }
2575 ++Index;
2576 if (AggrDeductionCandidateParamTypes)
2577 AggrDeductionCandidateParamTypes->push_back(CurrentObjectType);
2578 return !Seq;
2579 }
2580
2581 // Check the actual initialization for the designated object type.
2582 bool prevHadError = hadError;
2583
2584 // Temporarily remove the designator expression from the
2585 // initializer list that the child calls see, so that we don't try
2586 // to re-process the designator.
2587 unsigned OldIndex = Index;
2588 IList->setInit(OldIndex, DIE->getInit());
2589
2590 CheckSubElementType(Entity, IList, CurrentObjectType, Index, StructuredList,
2591 StructuredIndex, /*DirectlyDesignated=*/true);
2592
2593 // Restore the designated initializer expression in the syntactic
2594 // form of the initializer list.
2595 if (IList->getInit(OldIndex) != DIE->getInit())
2596 DIE->setInit(IList->getInit(OldIndex));
2597 IList->setInit(OldIndex, DIE);
2598
2599 return hadError && !prevHadError;
2600 }
2601
2602 DesignatedInitExpr::Designator *D = DIE->getDesignator(DesigIdx);
2603 bool IsFirstDesignator = (DesigIdx == 0);
2604 if (IsFirstDesignator ? FullyStructuredList : StructuredList) {
2605 // Determine the structural initializer list that corresponds to the
2606 // current subobject.
2607 if (IsFirstDesignator)
2608 StructuredList = FullyStructuredList;
2609 else {
2610 Expr *ExistingInit = StructuredIndex < StructuredList->getNumInits() ?
2611 StructuredList->getInit(StructuredIndex) : nullptr;
2612 if (!ExistingInit && StructuredList->hasArrayFiller())
2613 ExistingInit = StructuredList->getArrayFiller();
2614
2615 if (!ExistingInit)
2616 StructuredList = getStructuredSubobjectInit(
2617 IList, Index, CurrentObjectType, StructuredList, StructuredIndex,
2618 SourceRange(D->getBeginLoc(), DIE->getEndLoc()));
2619 else if (InitListExpr *Result = dyn_cast<InitListExpr>(ExistingInit))
2620 StructuredList = Result;
2621 else {
2622 // We are creating an initializer list that initializes the
2623 // subobjects of the current object, but there was already an
2624 // initialization that completely initialized the current
2625 // subobject, e.g., by a compound literal:
2626 //
2627 // struct X { int a, b; };
2628 // struct X xs[] = { [0] = (struct X) { 1, 2 }, [0].b = 3 };
2629 //
2630 // Here, xs[0].a == 1 and xs[0].b == 3, since the second,
2631 // designated initializer re-initializes only its current object
2632 // subobject [0].b.
2633 diagnoseInitOverride(ExistingInit,
2634 SourceRange(D->getBeginLoc(), DIE->getEndLoc()),
2635 /*UnionOverride=*/false,
2636 /*FullyOverwritten=*/false);
2637
2638 if (!VerifyOnly) {
2639 if (DesignatedInitUpdateExpr *E =
2640 dyn_cast<DesignatedInitUpdateExpr>(ExistingInit))
2641 StructuredList = E->getUpdater();
2642 else {
2643 DesignatedInitUpdateExpr *DIUE = new (SemaRef.Context)
2644 DesignatedInitUpdateExpr(SemaRef.Context, D->getBeginLoc(),
2645 ExistingInit, DIE->getEndLoc());
2646 StructuredList->updateInit(SemaRef.Context, StructuredIndex, DIUE);
2647 StructuredList = DIUE->getUpdater();
2648 }
2649 } else {
2650 // We don't need to track the structured representation of a
2651 // designated init update of an already-fully-initialized object in
2652 // verify-only mode. The only reason we would need the structure is
2653 // to determine where the uninitialized "holes" are, and in this
2654 // case, we know there aren't any and we can't introduce any.
2655 StructuredList = nullptr;
2656 }
2657 }
2658 }
2659 }
2660
2661 if (D->isFieldDesignator()) {
2662 // C99 6.7.8p7:
2663 //
2664 // If a designator has the form
2665 //
2666 // . identifier
2667 //
2668 // then the current object (defined below) shall have
2669 // structure or union type and the identifier shall be the
2670 // name of a member of that type.
2671 RecordDecl *RD = getRecordDecl(CurrentObjectType);
2672 if (!RD) {
2673 SourceLocation Loc = D->getDotLoc();
2674 if (Loc.isInvalid())
2675 Loc = D->getFieldLoc();
2676 if (!VerifyOnly)
2677 SemaRef.Diag(Loc, diag::err_field_designator_non_aggr)
2678 << SemaRef.getLangOpts().CPlusPlus << CurrentObjectType;
2679 ++Index;
2680 return true;
2681 }
2682
2683 FieldDecl *KnownField = D->getFieldDecl();
2684 if (!KnownField) {
2685 const IdentifierInfo *FieldName = D->getFieldName();
2686 ValueDecl *VD = SemaRef.tryLookupUnambiguousFieldDecl(RD, FieldName);
2687 if (auto *FD = dyn_cast_if_present<FieldDecl>(VD)) {
2688 KnownField = FD;
2689 } else if (auto *IFD = dyn_cast_if_present<IndirectFieldDecl>(VD)) {
2690 // In verify mode, don't modify the original.
2691 if (VerifyOnly)
2692 DIE = CloneDesignatedInitExpr(SemaRef, DIE);
2693 ExpandAnonymousFieldDesignator(SemaRef, DIE, DesigIdx, IFD);
2694 D = DIE->getDesignator(DesigIdx);
2695 KnownField = cast<FieldDecl>(*IFD->chain_begin());
2696 }
2697 if (!KnownField) {
2698 if (VerifyOnly) {
2699 ++Index;
2700 return true; // No typo correction when just trying this out.
2701 }
2702
2703 // We found a placeholder variable
2704 if (SemaRef.DiagRedefinedPlaceholderFieldDecl(DIE->getBeginLoc(), RD,
2705 FieldName)) {
2706 ++Index;
2707 return true;
2708 }
2709 // Name lookup found something, but it wasn't a field.
2710 if (DeclContextLookupResult Lookup = RD->lookup(FieldName);
2711 !Lookup.empty()) {
2712 SemaRef.Diag(D->getFieldLoc(), diag::err_field_designator_nonfield)
2713 << FieldName;
2714 SemaRef.Diag(Lookup.front()->getLocation(),
2715 diag::note_field_designator_found);
2716 ++Index;
2717 return true;
2718 }
2719
2720 // Name lookup didn't find anything.
2721 // Determine whether this was a typo for another field name.
2722 FieldInitializerValidatorCCC CCC(RD);
2723 if (TypoCorrection Corrected = SemaRef.CorrectTypo(
2724 DeclarationNameInfo(FieldName, D->getFieldLoc()),
2725 Sema::LookupMemberName, /*Scope=*/nullptr, /*SS=*/nullptr, CCC,
2726 Sema::CTK_ErrorRecovery, RD)) {
2727 SemaRef.diagnoseTypo(
2728 Corrected,
2729 SemaRef.PDiag(diag::err_field_designator_unknown_suggest)
2730 << FieldName << CurrentObjectType);
2731 KnownField = Corrected.getCorrectionDeclAs<FieldDecl>();
2732 hadError = true;
2733 } else {
2734 // Typo correction didn't find anything.
2735 SourceLocation Loc = D->getFieldLoc();
2736
2737 // The loc can be invalid with a "null" designator (i.e. an anonymous
2738 // union/struct). Do our best to approximate the location.
2739 if (Loc.isInvalid())
2740 Loc = IList->getBeginLoc();
2741
2742 SemaRef.Diag(Loc, diag::err_field_designator_unknown)
2743 << FieldName << CurrentObjectType << DIE->getSourceRange();
2744 ++Index;
2745 return true;
2746 }
2747 }
2748 }
2749
2750 unsigned NumBases = 0;
2751 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
2752 NumBases = CXXRD->getNumBases();
2753
2754 unsigned FieldIndex = NumBases;
2755
2756 for (auto *FI : RD->fields()) {
2757 if (FI->isUnnamedBitfield())
2758 continue;
2759 if (declaresSameEntity(KnownField, FI)) {
2760 KnownField = FI;
2761 break;
2762 }
2763 ++FieldIndex;
2764 }
2765
2766 RecordDecl::field_iterator Field =
2767 RecordDecl::field_iterator(DeclContext::decl_iterator(KnownField));
2768
2769 // All of the fields of a union are located at the same place in
2770 // the initializer list.
2771 if (RD->isUnion()) {
2772 FieldIndex = 0;
2773 if (StructuredList) {
2774 FieldDecl *CurrentField = StructuredList->getInitializedFieldInUnion();
2775 if (CurrentField && !declaresSameEntity(CurrentField, *Field)) {
2776 assert(StructuredList->getNumInits() == 1
2777 && "A union should never have more than one initializer!");
2778
2779 Expr *ExistingInit = StructuredList->getInit(0);
2780 if (ExistingInit) {
2781 // We're about to throw away an initializer, emit warning.
2782 diagnoseInitOverride(
2783 ExistingInit, SourceRange(D->getBeginLoc(), DIE->getEndLoc()),
2784 /*UnionOverride=*/true,
2785 /*FullyOverwritten=*/SemaRef.getLangOpts().CPlusPlus ? false
2786 : true);
2787 }
2788
2789 // remove existing initializer
2790 StructuredList->resizeInits(SemaRef.Context, 0);
2791 StructuredList->setInitializedFieldInUnion(nullptr);
2792 }
2793
2794 StructuredList->setInitializedFieldInUnion(*Field);
2795 }
2796 }
2797
2798 // Make sure we can use this declaration.
2799 bool InvalidUse;
2800 if (VerifyOnly)
2801 InvalidUse = !SemaRef.CanUseDecl(*Field, TreatUnavailableAsInvalid);
2802 else
2803 InvalidUse = SemaRef.DiagnoseUseOfDecl(*Field, D->getFieldLoc());
2804 if (InvalidUse) {
2805 ++Index;
2806 return true;
2807 }
2808
2809 // C++20 [dcl.init.list]p3:
2810 // The ordered identifiers in the designators of the designated-
2811 // initializer-list shall form a subsequence of the ordered identifiers
2812 // in the direct non-static data members of T.
2813 //
2814 // Note that this is not a condition on forming the aggregate
2815 // initialization, only on actually performing initialization,
2816 // so it is not checked in VerifyOnly mode.
2817 //
2818 // FIXME: This is the only reordering diagnostic we produce, and it only
2819 // catches cases where we have a top-level field designator that jumps
2820 // backwards. This is the only such case that is reachable in an
2821 // otherwise-valid C++20 program, so is the only case that's required for
2822 // conformance, but for consistency, we should diagnose all the other
2823 // cases where a designator takes us backwards too.
2824 if (IsFirstDesignator && !VerifyOnly && SemaRef.getLangOpts().CPlusPlus &&
2825 NextField &&
2826 (*NextField == RD->field_end() ||
2827 (*NextField)->getFieldIndex() > Field->getFieldIndex() + 1)) {
2828 // Find the field that we just initialized.
2829 FieldDecl *PrevField = nullptr;
2830 for (auto FI = RD->field_begin(); FI != RD->field_end(); ++FI) {
2831 if (FI->isUnnamedBitfield())
2832 continue;
2833 if (*NextField != RD->field_end() &&
2834 declaresSameEntity(*FI, **NextField))
2835 break;
2836 PrevField = *FI;
2837 }
2838
2839 if (PrevField &&
2840 PrevField->getFieldIndex() > KnownField->getFieldIndex()) {
2841 SemaRef.Diag(DIE->getInit()->getBeginLoc(),
2842 diag::ext_designated_init_reordered)
2843 << KnownField << PrevField << DIE->getSourceRange();
2844
2845 unsigned OldIndex = StructuredIndex - 1;
2846 if (StructuredList && OldIndex <= StructuredList->getNumInits()) {
2847 if (Expr *PrevInit = StructuredList->getInit(OldIndex)) {
2848 SemaRef.Diag(PrevInit->getBeginLoc(),
2849 diag::note_previous_field_init)
2850 << PrevField << PrevInit->getSourceRange();
2851 }
2852 }
2853 }
2854 }
2855
2856
2857 // Update the designator with the field declaration.
2858 if (!VerifyOnly)
2859 D->setFieldDecl(*Field);
2860
2861 // Make sure that our non-designated initializer list has space
2862 // for a subobject corresponding to this field.
2863 if (StructuredList && FieldIndex >= StructuredList->getNumInits())
2864 StructuredList->resizeInits(SemaRef.Context, FieldIndex + 1);
2865
2866 // This designator names a flexible array member.
2867 if (Field->getType()->isIncompleteArrayType()) {
2868 bool Invalid = false;
2869 if ((DesigIdx + 1) != DIE->size()) {
2870 // We can't designate an object within the flexible array
2871 // member (because GCC doesn't allow it).
2872 if (!VerifyOnly) {
2873 DesignatedInitExpr::Designator *NextD
2874 = DIE->getDesignator(DesigIdx + 1);
2875 SemaRef.Diag(NextD->getBeginLoc(),
2876 diag::err_designator_into_flexible_array_member)
2877 << SourceRange(NextD->getBeginLoc(), DIE->getEndLoc());
2878 SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
2879 << *Field;
2880 }
2881 Invalid = true;
2882 }
2883
2884 if (!hadError && !isa<InitListExpr>(DIE->getInit()) &&
2885 !isa<StringLiteral>(DIE->getInit())) {
2886 // The initializer is not an initializer list.
2887 if (!VerifyOnly) {
2888 SemaRef.Diag(DIE->getInit()->getBeginLoc(),
2889 diag::err_flexible_array_init_needs_braces)
2890 << DIE->getInit()->getSourceRange();
2891 SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
2892 << *Field;
2893 }
2894 Invalid = true;
2895 }
2896
2897 // Check GNU flexible array initializer.
2898 if (!Invalid && CheckFlexibleArrayInit(Entity, DIE->getInit(), *Field,
2899 TopLevelObject))
2900 Invalid = true;
2901
2902 if (Invalid) {
2903 ++Index;
2904 return true;
2905 }
2906
2907 // Initialize the array.
2908 bool prevHadError = hadError;
2909 unsigned newStructuredIndex = FieldIndex;
2910 unsigned OldIndex = Index;
2911 IList->setInit(Index, DIE->getInit());
2912
2913 InitializedEntity MemberEntity =
2914 InitializedEntity::InitializeMember(*Field, &Entity);
2915 CheckSubElementType(MemberEntity, IList, Field->getType(), Index,
2916 StructuredList, newStructuredIndex);
2917
2918 IList->setInit(OldIndex, DIE);
2919 if (hadError && !prevHadError) {
2920 ++Field;
2921 ++FieldIndex;
2922 if (NextField)
2923 *NextField = Field;
2924 StructuredIndex = FieldIndex;
2925 return true;
2926 }
2927 } else {
2928 // Recurse to check later designated subobjects.
2929 QualType FieldType = Field->getType();
2930 unsigned newStructuredIndex = FieldIndex;
2931
2932 InitializedEntity MemberEntity =
2933 InitializedEntity::InitializeMember(*Field, &Entity);
2934 if (CheckDesignatedInitializer(MemberEntity, IList, DIE, DesigIdx + 1,
2935 FieldType, nullptr, nullptr, Index,
2936 StructuredList, newStructuredIndex,
2937 FinishSubobjectInit, false))
2938 return true;
2939 }
2940
2941 // Find the position of the next field to be initialized in this
2942 // subobject.
2943 ++Field;
2944 ++FieldIndex;
2945
2946 // If this the first designator, our caller will continue checking
2947 // the rest of this struct/class/union subobject.
2948 if (IsFirstDesignator) {
2949 if (Field != RD->field_end() && Field->isUnnamedBitfield())
2950 ++Field;
2951
2952 if (NextField)
2953 *NextField = Field;
2954
2955 StructuredIndex = FieldIndex;
2956 return false;
2957 }
2958
2959 if (!FinishSubobjectInit)
2960 return false;
2961
2962 // We've already initialized something in the union; we're done.
2963 if (RD->isUnion())
2964 return hadError;
2965
2966 // Check the remaining fields within this class/struct/union subobject.
2967 bool prevHadError = hadError;
2968
2969 auto NoBases =
2970 CXXRecordDecl::base_class_range(CXXRecordDecl::base_class_iterator(),
2971 CXXRecordDecl::base_class_iterator());
2972 CheckStructUnionTypes(Entity, IList, CurrentObjectType, NoBases, Field,
2973 false, Index, StructuredList, FieldIndex);
2974 return hadError && !prevHadError;
2975 }
2976
2977 // C99 6.7.8p6:
2978 //
2979 // If a designator has the form
2980 //
2981 // [ constant-expression ]
2982 //
2983 // then the current object (defined below) shall have array
2984 // type and the expression shall be an integer constant
2985 // expression. If the array is of unknown size, any
2986 // nonnegative value is valid.
2987 //
2988 // Additionally, cope with the GNU extension that permits
2989 // designators of the form
2990 //
2991 // [ constant-expression ... constant-expression ]
2992 const ArrayType *AT = SemaRef.Context.getAsArrayType(CurrentObjectType);
2993 if (!AT) {
2994 if (!VerifyOnly)
2995 SemaRef.Diag(D->getLBracketLoc(), diag::err_array_designator_non_array)
2996 << CurrentObjectType;
2997 ++Index;
2998 return true;
2999 }
3000
3001 Expr *IndexExpr = nullptr;
3002 llvm::APSInt DesignatedStartIndex, DesignatedEndIndex;
3003 if (D->isArrayDesignator()) {
3004 IndexExpr = DIE->getArrayIndex(*D);
3005 DesignatedStartIndex = IndexExpr->EvaluateKnownConstInt(SemaRef.Context);
3006 DesignatedEndIndex = DesignatedStartIndex;
3007 } else {
3008 assert(D->isArrayRangeDesignator() && "Need array-range designator");
3009
3010 DesignatedStartIndex =
3011 DIE->getArrayRangeStart(*D)->EvaluateKnownConstInt(SemaRef.Context);
3012 DesignatedEndIndex =
3013 DIE->getArrayRangeEnd(*D)->EvaluateKnownConstInt(SemaRef.Context);
3014 IndexExpr = DIE->getArrayRangeEnd(*D);
3015
3016 // Codegen can't handle evaluating array range designators that have side
3017 // effects, because we replicate the AST value for each initialized element.
3018 // As such, set the sawArrayRangeDesignator() bit if we initialize multiple
3019 // elements with something that has a side effect, so codegen can emit an
3020 // "error unsupported" error instead of miscompiling the app.
3021 if (DesignatedStartIndex.getZExtValue()!=DesignatedEndIndex.getZExtValue()&&
3022 DIE->getInit()->HasSideEffects(SemaRef.Context) && !VerifyOnly)
3023 FullyStructuredList->sawArrayRangeDesignator();
3024 }
3025
3026 if (isa<ConstantArrayType>(AT)) {
3027 llvm::APSInt MaxElements(cast<ConstantArrayType>(AT)->getSize(), false);
3028 DesignatedStartIndex
3029 = DesignatedStartIndex.extOrTrunc(MaxElements.getBitWidth());
3030 DesignatedStartIndex.setIsUnsigned(MaxElements.isUnsigned());
3031 DesignatedEndIndex
3032 = DesignatedEndIndex.extOrTrunc(MaxElements.getBitWidth());
3033 DesignatedEndIndex.setIsUnsigned(MaxElements.isUnsigned());
3034 if (DesignatedEndIndex >= MaxElements) {
3035 if (!VerifyOnly)
3036 SemaRef.Diag(IndexExpr->getBeginLoc(),
3037 diag::err_array_designator_too_large)
3038 << toString(DesignatedEndIndex, 10) << toString(MaxElements, 10)
3039 << IndexExpr->getSourceRange();
3040 ++Index;
3041 return true;
3042 }
3043 } else {
3044 unsigned DesignatedIndexBitWidth =
3045 ConstantArrayType::getMaxSizeBits(SemaRef.Context);
3046 DesignatedStartIndex =
3047 DesignatedStartIndex.extOrTrunc(DesignatedIndexBitWidth);
3048 DesignatedEndIndex =
3049 DesignatedEndIndex.extOrTrunc(DesignatedIndexBitWidth);
3050 DesignatedStartIndex.setIsUnsigned(true);
3051 DesignatedEndIndex.setIsUnsigned(true);
3052 }
3053
3054 bool IsStringLiteralInitUpdate =
3055 StructuredList && StructuredList->isStringLiteralInit();
3056 if (IsStringLiteralInitUpdate && VerifyOnly) {
3057 // We're just verifying an update to a string literal init. We don't need
3058 // to split the string up into individual characters to do that.
3059 StructuredList = nullptr;
3060 } else if (IsStringLiteralInitUpdate) {
3061 // We're modifying a string literal init; we have to decompose the string
3062 // so we can modify the individual characters.
3063 ASTContext &Context = SemaRef.Context;
3064 Expr *SubExpr = StructuredList->getInit(0)->IgnoreParenImpCasts();
3065
3066 // Compute the character type
3067 QualType CharTy = AT->getElementType();
3068
3069 // Compute the type of the integer literals.
3070 QualType PromotedCharTy = CharTy;
3071 if (Context.isPromotableIntegerType(CharTy))
3072 PromotedCharTy = Context.getPromotedIntegerType(CharTy);
3073 unsigned PromotedCharTyWidth = Context.getTypeSize(PromotedCharTy);
3074
3075 if (StringLiteral *SL = dyn_cast<StringLiteral>(SubExpr)) {
3076 // Get the length of the string.
3077 uint64_t StrLen = SL->getLength();
3078 if (cast<ConstantArrayType>(AT)->getSize().ult(StrLen))
3079 StrLen = cast<ConstantArrayType>(AT)->getSize().getZExtValue();
3080 StructuredList->resizeInits(Context, StrLen);
3081
3082 // Build a literal for each character in the string, and put them into
3083 // the init list.
3084 for (unsigned i = 0, e = StrLen; i != e; ++i) {
3085 llvm::APInt CodeUnit(PromotedCharTyWidth, SL->getCodeUnit(i));
3086 Expr *Init = new (Context) IntegerLiteral(
3087 Context, CodeUnit, PromotedCharTy, SubExpr->getExprLoc());
3088 if (CharTy != PromotedCharTy)
3089 Init = ImplicitCastExpr::Create(Context, CharTy, CK_IntegralCast,
3090 Init, nullptr, VK_PRValue,
3091 FPOptionsOverride());
3092 StructuredList->updateInit(Context, i, Init);
3093 }
3094 } else {
3095 ObjCEncodeExpr *E = cast<ObjCEncodeExpr>(SubExpr);
3096 std::string Str;
3097 Context.getObjCEncodingForType(E->getEncodedType(), Str);
3098
3099 // Get the length of the string.
3100 uint64_t StrLen = Str.size();
3101 if (cast<ConstantArrayType>(AT)->getSize().ult(StrLen))
3102 StrLen = cast<ConstantArrayType>(AT)->getSize().getZExtValue();
3103 StructuredList->resizeInits(Context, StrLen);
3104
3105 // Build a literal for each character in the string, and put them into
3106 // the init list.
3107 for (unsigned i = 0, e = StrLen; i != e; ++i) {
3108 llvm::APInt CodeUnit(PromotedCharTyWidth, Str[i]);
3109 Expr *Init = new (Context) IntegerLiteral(
3110 Context, CodeUnit, PromotedCharTy, SubExpr->getExprLoc());
3111 if (CharTy != PromotedCharTy)
3112 Init = ImplicitCastExpr::Create(Context, CharTy, CK_IntegralCast,
3113 Init, nullptr, VK_PRValue,
3114 FPOptionsOverride());
3115 StructuredList->updateInit(Context, i, Init);
3116 }
3117 }
3118 }
3119
3120 // Make sure that our non-designated initializer list has space
3121 // for a subobject corresponding to this array element.
3122 if (StructuredList &&
3123 DesignatedEndIndex.getZExtValue() >= StructuredList->getNumInits())
3124 StructuredList->resizeInits(SemaRef.Context,
3125 DesignatedEndIndex.getZExtValue() + 1);
3126
3127 // Repeatedly perform subobject initializations in the range
3128 // [DesignatedStartIndex, DesignatedEndIndex].
3129
3130 // Move to the next designator
3131 unsigned ElementIndex = DesignatedStartIndex.getZExtValue();
3132 unsigned OldIndex = Index;
3133
3134 InitializedEntity ElementEntity =
3135 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
3136
3137 while (DesignatedStartIndex <= DesignatedEndIndex) {
3138 // Recurse to check later designated subobjects.
3139 QualType ElementType = AT->getElementType();
3140 Index = OldIndex;
3141
3142 ElementEntity.setElementIndex(ElementIndex);
3143 if (CheckDesignatedInitializer(
3144 ElementEntity, IList, DIE, DesigIdx + 1, ElementType, nullptr,
3145 nullptr, Index, StructuredList, ElementIndex,
3146 FinishSubobjectInit && (DesignatedStartIndex == DesignatedEndIndex),
3147 false))
3148 return true;
3149
3150 // Move to the next index in the array that we'll be initializing.
3151 ++DesignatedStartIndex;
3152 ElementIndex = DesignatedStartIndex.getZExtValue();
3153 }
3154
3155 // If this the first designator, our caller will continue checking
3156 // the rest of this array subobject.
3157 if (IsFirstDesignator) {
3158 if (NextElementIndex)
3159 *NextElementIndex = DesignatedStartIndex;
3160 StructuredIndex = ElementIndex;
3161 return false;
3162 }
3163
3164 if (!FinishSubobjectInit)
3165 return false;
3166
3167 // Check the remaining elements within this array subobject.
3168 bool prevHadError = hadError;
3169 CheckArrayType(Entity, IList, CurrentObjectType, DesignatedStartIndex,
3170 /*SubobjectIsDesignatorContext=*/false, Index,
3171 StructuredList, ElementIndex);
3172 return hadError && !prevHadError;
3173 }
3174
3175 // Get the structured initializer list for a subobject of type
3176 // @p CurrentObjectType.
3177 InitListExpr *
getStructuredSubobjectInit(InitListExpr * IList,unsigned Index,QualType CurrentObjectType,InitListExpr * StructuredList,unsigned StructuredIndex,SourceRange InitRange,bool IsFullyOverwritten)3178 InitListChecker::getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
3179 QualType CurrentObjectType,
3180 InitListExpr *StructuredList,
3181 unsigned StructuredIndex,
3182 SourceRange InitRange,
3183 bool IsFullyOverwritten) {
3184 if (!StructuredList)
3185 return nullptr;
3186
3187 Expr *ExistingInit = nullptr;
3188 if (StructuredIndex < StructuredList->getNumInits())
3189 ExistingInit = StructuredList->getInit(StructuredIndex);
3190
3191 if (InitListExpr *Result = dyn_cast_or_null<InitListExpr>(ExistingInit))
3192 // There might have already been initializers for subobjects of the current
3193 // object, but a subsequent initializer list will overwrite the entirety
3194 // of the current object. (See DR 253 and C99 6.7.8p21). e.g.,
3195 //
3196 // struct P { char x[6]; };
3197 // struct P l = { .x[2] = 'x', .x = { [0] = 'f' } };
3198 //
3199 // The first designated initializer is ignored, and l.x is just "f".
3200 if (!IsFullyOverwritten)
3201 return Result;
3202
3203 if (ExistingInit) {
3204 // We are creating an initializer list that initializes the
3205 // subobjects of the current object, but there was already an
3206 // initialization that completely initialized the current
3207 // subobject:
3208 //
3209 // struct X { int a, b; };
3210 // struct X xs[] = { [0] = { 1, 2 }, [0].b = 3 };
3211 //
3212 // Here, xs[0].a == 1 and xs[0].b == 3, since the second,
3213 // designated initializer overwrites the [0].b initializer
3214 // from the prior initialization.
3215 //
3216 // When the existing initializer is an expression rather than an
3217 // initializer list, we cannot decompose and update it in this way.
3218 // For example:
3219 //
3220 // struct X xs[] = { [0] = (struct X) { 1, 2 }, [0].b = 3 };
3221 //
3222 // This case is handled by CheckDesignatedInitializer.
3223 diagnoseInitOverride(ExistingInit, InitRange);
3224 }
3225
3226 unsigned ExpectedNumInits = 0;
3227 if (Index < IList->getNumInits()) {
3228 if (auto *Init = dyn_cast_or_null<InitListExpr>(IList->getInit(Index)))
3229 ExpectedNumInits = Init->getNumInits();
3230 else
3231 ExpectedNumInits = IList->getNumInits() - Index;
3232 }
3233
3234 InitListExpr *Result =
3235 createInitListExpr(CurrentObjectType, InitRange, ExpectedNumInits);
3236
3237 // Link this new initializer list into the structured initializer
3238 // lists.
3239 StructuredList->updateInit(SemaRef.Context, StructuredIndex, Result);
3240 return Result;
3241 }
3242
3243 InitListExpr *
createInitListExpr(QualType CurrentObjectType,SourceRange InitRange,unsigned ExpectedNumInits)3244 InitListChecker::createInitListExpr(QualType CurrentObjectType,
3245 SourceRange InitRange,
3246 unsigned ExpectedNumInits) {
3247 InitListExpr *Result = new (SemaRef.Context) InitListExpr(
3248 SemaRef.Context, InitRange.getBegin(), std::nullopt, InitRange.getEnd());
3249
3250 QualType ResultType = CurrentObjectType;
3251 if (!ResultType->isArrayType())
3252 ResultType = ResultType.getNonLValueExprType(SemaRef.Context);
3253 Result->setType(ResultType);
3254
3255 // Pre-allocate storage for the structured initializer list.
3256 unsigned NumElements = 0;
3257
3258 if (const ArrayType *AType
3259 = SemaRef.Context.getAsArrayType(CurrentObjectType)) {
3260 if (const ConstantArrayType *CAType = dyn_cast<ConstantArrayType>(AType)) {
3261 NumElements = CAType->getSize().getZExtValue();
3262 // Simple heuristic so that we don't allocate a very large
3263 // initializer with many empty entries at the end.
3264 if (NumElements > ExpectedNumInits)
3265 NumElements = 0;
3266 }
3267 } else if (const VectorType *VType = CurrentObjectType->getAs<VectorType>()) {
3268 NumElements = VType->getNumElements();
3269 } else if (CurrentObjectType->isRecordType()) {
3270 NumElements = numStructUnionElements(CurrentObjectType);
3271 } else if (CurrentObjectType->isDependentType()) {
3272 NumElements = 1;
3273 }
3274
3275 Result->reserveInits(SemaRef.Context, NumElements);
3276
3277 return Result;
3278 }
3279
3280 /// Update the initializer at index @p StructuredIndex within the
3281 /// structured initializer list to the value @p expr.
UpdateStructuredListElement(InitListExpr * StructuredList,unsigned & StructuredIndex,Expr * expr)3282 void InitListChecker::UpdateStructuredListElement(InitListExpr *StructuredList,
3283 unsigned &StructuredIndex,
3284 Expr *expr) {
3285 // No structured initializer list to update
3286 if (!StructuredList)
3287 return;
3288
3289 if (Expr *PrevInit = StructuredList->updateInit(SemaRef.Context,
3290 StructuredIndex, expr)) {
3291 // This initializer overwrites a previous initializer.
3292 // No need to diagnose when `expr` is nullptr because a more relevant
3293 // diagnostic has already been issued and this diagnostic is potentially
3294 // noise.
3295 if (expr)
3296 diagnoseInitOverride(PrevInit, expr->getSourceRange());
3297 }
3298
3299 ++StructuredIndex;
3300 }
3301
3302 /// Determine whether we can perform aggregate initialization for the purposes
3303 /// of overload resolution.
CanPerformAggregateInitializationForOverloadResolution(const InitializedEntity & Entity,InitListExpr * From)3304 bool Sema::CanPerformAggregateInitializationForOverloadResolution(
3305 const InitializedEntity &Entity, InitListExpr *From) {
3306 QualType Type = Entity.getType();
3307 InitListChecker Check(*this, Entity, From, Type, /*VerifyOnly=*/true,
3308 /*TreatUnavailableAsInvalid=*/false,
3309 /*InOverloadResolution=*/true);
3310 return !Check.HadError();
3311 }
3312
3313 /// Check that the given Index expression is a valid array designator
3314 /// value. This is essentially just a wrapper around
3315 /// VerifyIntegerConstantExpression that also checks for negative values
3316 /// and produces a reasonable diagnostic if there is a
3317 /// failure. Returns the index expression, possibly with an implicit cast
3318 /// added, on success. If everything went okay, Value will receive the
3319 /// value of the constant expression.
3320 static ExprResult
CheckArrayDesignatorExpr(Sema & S,Expr * Index,llvm::APSInt & Value)3321 CheckArrayDesignatorExpr(Sema &S, Expr *Index, llvm::APSInt &Value) {
3322 SourceLocation Loc = Index->getBeginLoc();
3323
3324 // Make sure this is an integer constant expression.
3325 ExprResult Result =
3326 S.VerifyIntegerConstantExpression(Index, &Value, Sema::AllowFold);
3327 if (Result.isInvalid())
3328 return Result;
3329
3330 if (Value.isSigned() && Value.isNegative())
3331 return S.Diag(Loc, diag::err_array_designator_negative)
3332 << toString(Value, 10) << Index->getSourceRange();
3333
3334 Value.setIsUnsigned(true);
3335 return Result;
3336 }
3337
ActOnDesignatedInitializer(Designation & Desig,SourceLocation EqualOrColonLoc,bool GNUSyntax,ExprResult Init)3338 ExprResult Sema::ActOnDesignatedInitializer(Designation &Desig,
3339 SourceLocation EqualOrColonLoc,
3340 bool GNUSyntax,
3341 ExprResult Init) {
3342 typedef DesignatedInitExpr::Designator ASTDesignator;
3343
3344 bool Invalid = false;
3345 SmallVector<ASTDesignator, 32> Designators;
3346 SmallVector<Expr *, 32> InitExpressions;
3347
3348 // Build designators and check array designator expressions.
3349 for (unsigned Idx = 0; Idx < Desig.getNumDesignators(); ++Idx) {
3350 const Designator &D = Desig.getDesignator(Idx);
3351
3352 if (D.isFieldDesignator()) {
3353 Designators.push_back(ASTDesignator::CreateFieldDesignator(
3354 D.getFieldDecl(), D.getDotLoc(), D.getFieldLoc()));
3355 } else if (D.isArrayDesignator()) {
3356 Expr *Index = static_cast<Expr *>(D.getArrayIndex());
3357 llvm::APSInt IndexValue;
3358 if (!Index->isTypeDependent() && !Index->isValueDependent())
3359 Index = CheckArrayDesignatorExpr(*this, Index, IndexValue).get();
3360 if (!Index)
3361 Invalid = true;
3362 else {
3363 Designators.push_back(ASTDesignator::CreateArrayDesignator(
3364 InitExpressions.size(), D.getLBracketLoc(), D.getRBracketLoc()));
3365 InitExpressions.push_back(Index);
3366 }
3367 } else if (D.isArrayRangeDesignator()) {
3368 Expr *StartIndex = static_cast<Expr *>(D.getArrayRangeStart());
3369 Expr *EndIndex = static_cast<Expr *>(D.getArrayRangeEnd());
3370 llvm::APSInt StartValue;
3371 llvm::APSInt EndValue;
3372 bool StartDependent = StartIndex->isTypeDependent() ||
3373 StartIndex->isValueDependent();
3374 bool EndDependent = EndIndex->isTypeDependent() ||
3375 EndIndex->isValueDependent();
3376 if (!StartDependent)
3377 StartIndex =
3378 CheckArrayDesignatorExpr(*this, StartIndex, StartValue).get();
3379 if (!EndDependent)
3380 EndIndex = CheckArrayDesignatorExpr(*this, EndIndex, EndValue).get();
3381
3382 if (!StartIndex || !EndIndex)
3383 Invalid = true;
3384 else {
3385 // Make sure we're comparing values with the same bit width.
3386 if (StartDependent || EndDependent) {
3387 // Nothing to compute.
3388 } else if (StartValue.getBitWidth() > EndValue.getBitWidth())
3389 EndValue = EndValue.extend(StartValue.getBitWidth());
3390 else if (StartValue.getBitWidth() < EndValue.getBitWidth())
3391 StartValue = StartValue.extend(EndValue.getBitWidth());
3392
3393 if (!StartDependent && !EndDependent && EndValue < StartValue) {
3394 Diag(D.getEllipsisLoc(), diag::err_array_designator_empty_range)
3395 << toString(StartValue, 10) << toString(EndValue, 10)
3396 << StartIndex->getSourceRange() << EndIndex->getSourceRange();
3397 Invalid = true;
3398 } else {
3399 Designators.push_back(ASTDesignator::CreateArrayRangeDesignator(
3400 InitExpressions.size(), D.getLBracketLoc(), D.getEllipsisLoc(),
3401 D.getRBracketLoc()));
3402 InitExpressions.push_back(StartIndex);
3403 InitExpressions.push_back(EndIndex);
3404 }
3405 }
3406 }
3407 }
3408
3409 if (Invalid || Init.isInvalid())
3410 return ExprError();
3411
3412 return DesignatedInitExpr::Create(Context, Designators, InitExpressions,
3413 EqualOrColonLoc, GNUSyntax,
3414 Init.getAs<Expr>());
3415 }
3416
3417 //===----------------------------------------------------------------------===//
3418 // Initialization entity
3419 //===----------------------------------------------------------------------===//
3420
InitializedEntity(ASTContext & Context,unsigned Index,const InitializedEntity & Parent)3421 InitializedEntity::InitializedEntity(ASTContext &Context, unsigned Index,
3422 const InitializedEntity &Parent)
3423 : Parent(&Parent), Index(Index)
3424 {
3425 if (const ArrayType *AT = Context.getAsArrayType(Parent.getType())) {
3426 Kind = EK_ArrayElement;
3427 Type = AT->getElementType();
3428 } else if (const VectorType *VT = Parent.getType()->getAs<VectorType>()) {
3429 Kind = EK_VectorElement;
3430 Type = VT->getElementType();
3431 } else {
3432 const ComplexType *CT = Parent.getType()->getAs<ComplexType>();
3433 assert(CT && "Unexpected type");
3434 Kind = EK_ComplexElement;
3435 Type = CT->getElementType();
3436 }
3437 }
3438
3439 InitializedEntity
InitializeBase(ASTContext & Context,const CXXBaseSpecifier * Base,bool IsInheritedVirtualBase,const InitializedEntity * Parent)3440 InitializedEntity::InitializeBase(ASTContext &Context,
3441 const CXXBaseSpecifier *Base,
3442 bool IsInheritedVirtualBase,
3443 const InitializedEntity *Parent) {
3444 InitializedEntity Result;
3445 Result.Kind = EK_Base;
3446 Result.Parent = Parent;
3447 Result.Base = {Base, IsInheritedVirtualBase};
3448 Result.Type = Base->getType();
3449 return Result;
3450 }
3451
getName() const3452 DeclarationName InitializedEntity::getName() const {
3453 switch (getKind()) {
3454 case EK_Parameter:
3455 case EK_Parameter_CF_Audited: {
3456 ParmVarDecl *D = Parameter.getPointer();
3457 return (D ? D->getDeclName() : DeclarationName());
3458 }
3459
3460 case EK_Variable:
3461 case EK_Member:
3462 case EK_ParenAggInitMember:
3463 case EK_Binding:
3464 case EK_TemplateParameter:
3465 return Variable.VariableOrMember->getDeclName();
3466
3467 case EK_LambdaCapture:
3468 return DeclarationName(Capture.VarID);
3469
3470 case EK_Result:
3471 case EK_StmtExprResult:
3472 case EK_Exception:
3473 case EK_New:
3474 case EK_Temporary:
3475 case EK_Base:
3476 case EK_Delegating:
3477 case EK_ArrayElement:
3478 case EK_VectorElement:
3479 case EK_ComplexElement:
3480 case EK_BlockElement:
3481 case EK_LambdaToBlockConversionBlockElement:
3482 case EK_CompoundLiteralInit:
3483 case EK_RelatedResult:
3484 return DeclarationName();
3485 }
3486
3487 llvm_unreachable("Invalid EntityKind!");
3488 }
3489
getDecl() const3490 ValueDecl *InitializedEntity::getDecl() const {
3491 switch (getKind()) {
3492 case EK_Variable:
3493 case EK_Member:
3494 case EK_ParenAggInitMember:
3495 case EK_Binding:
3496 case EK_TemplateParameter:
3497 return Variable.VariableOrMember;
3498
3499 case EK_Parameter:
3500 case EK_Parameter_CF_Audited:
3501 return Parameter.getPointer();
3502
3503 case EK_Result:
3504 case EK_StmtExprResult:
3505 case EK_Exception:
3506 case EK_New:
3507 case EK_Temporary:
3508 case EK_Base:
3509 case EK_Delegating:
3510 case EK_ArrayElement:
3511 case EK_VectorElement:
3512 case EK_ComplexElement:
3513 case EK_BlockElement:
3514 case EK_LambdaToBlockConversionBlockElement:
3515 case EK_LambdaCapture:
3516 case EK_CompoundLiteralInit:
3517 case EK_RelatedResult:
3518 return nullptr;
3519 }
3520
3521 llvm_unreachable("Invalid EntityKind!");
3522 }
3523
allowsNRVO() const3524 bool InitializedEntity::allowsNRVO() const {
3525 switch (getKind()) {
3526 case EK_Result:
3527 case EK_Exception:
3528 return LocAndNRVO.NRVO;
3529
3530 case EK_StmtExprResult:
3531 case EK_Variable:
3532 case EK_Parameter:
3533 case EK_Parameter_CF_Audited:
3534 case EK_TemplateParameter:
3535 case EK_Member:
3536 case EK_ParenAggInitMember:
3537 case EK_Binding:
3538 case EK_New:
3539 case EK_Temporary:
3540 case EK_CompoundLiteralInit:
3541 case EK_Base:
3542 case EK_Delegating:
3543 case EK_ArrayElement:
3544 case EK_VectorElement:
3545 case EK_ComplexElement:
3546 case EK_BlockElement:
3547 case EK_LambdaToBlockConversionBlockElement:
3548 case EK_LambdaCapture:
3549 case EK_RelatedResult:
3550 break;
3551 }
3552
3553 return false;
3554 }
3555
dumpImpl(raw_ostream & OS) const3556 unsigned InitializedEntity::dumpImpl(raw_ostream &OS) const {
3557 assert(getParent() != this);
3558 unsigned Depth = getParent() ? getParent()->dumpImpl(OS) : 0;
3559 for (unsigned I = 0; I != Depth; ++I)
3560 OS << "`-";
3561
3562 switch (getKind()) {
3563 case EK_Variable: OS << "Variable"; break;
3564 case EK_Parameter: OS << "Parameter"; break;
3565 case EK_Parameter_CF_Audited: OS << "CF audited function Parameter";
3566 break;
3567 case EK_TemplateParameter: OS << "TemplateParameter"; break;
3568 case EK_Result: OS << "Result"; break;
3569 case EK_StmtExprResult: OS << "StmtExprResult"; break;
3570 case EK_Exception: OS << "Exception"; break;
3571 case EK_Member:
3572 case EK_ParenAggInitMember:
3573 OS << "Member";
3574 break;
3575 case EK_Binding: OS << "Binding"; break;
3576 case EK_New: OS << "New"; break;
3577 case EK_Temporary: OS << "Temporary"; break;
3578 case EK_CompoundLiteralInit: OS << "CompoundLiteral";break;
3579 case EK_RelatedResult: OS << "RelatedResult"; break;
3580 case EK_Base: OS << "Base"; break;
3581 case EK_Delegating: OS << "Delegating"; break;
3582 case EK_ArrayElement: OS << "ArrayElement " << Index; break;
3583 case EK_VectorElement: OS << "VectorElement " << Index; break;
3584 case EK_ComplexElement: OS << "ComplexElement " << Index; break;
3585 case EK_BlockElement: OS << "Block"; break;
3586 case EK_LambdaToBlockConversionBlockElement:
3587 OS << "Block (lambda)";
3588 break;
3589 case EK_LambdaCapture:
3590 OS << "LambdaCapture ";
3591 OS << DeclarationName(Capture.VarID);
3592 break;
3593 }
3594
3595 if (auto *D = getDecl()) {
3596 OS << " ";
3597 D->printQualifiedName(OS);
3598 }
3599
3600 OS << " '" << getType() << "'\n";
3601
3602 return Depth + 1;
3603 }
3604
dump() const3605 LLVM_DUMP_METHOD void InitializedEntity::dump() const {
3606 dumpImpl(llvm::errs());
3607 }
3608
3609 //===----------------------------------------------------------------------===//
3610 // Initialization sequence
3611 //===----------------------------------------------------------------------===//
3612
Destroy()3613 void InitializationSequence::Step::Destroy() {
3614 switch (Kind) {
3615 case SK_ResolveAddressOfOverloadedFunction:
3616 case SK_CastDerivedToBasePRValue:
3617 case SK_CastDerivedToBaseXValue:
3618 case SK_CastDerivedToBaseLValue:
3619 case SK_BindReference:
3620 case SK_BindReferenceToTemporary:
3621 case SK_FinalCopy:
3622 case SK_ExtraneousCopyToTemporary:
3623 case SK_UserConversion:
3624 case SK_QualificationConversionPRValue:
3625 case SK_QualificationConversionXValue:
3626 case SK_QualificationConversionLValue:
3627 case SK_FunctionReferenceConversion:
3628 case SK_AtomicConversion:
3629 case SK_ListInitialization:
3630 case SK_UnwrapInitList:
3631 case SK_RewrapInitList:
3632 case SK_ConstructorInitialization:
3633 case SK_ConstructorInitializationFromList:
3634 case SK_ZeroInitialization:
3635 case SK_CAssignment:
3636 case SK_StringInit:
3637 case SK_ObjCObjectConversion:
3638 case SK_ArrayLoopIndex:
3639 case SK_ArrayLoopInit:
3640 case SK_ArrayInit:
3641 case SK_GNUArrayInit:
3642 case SK_ParenthesizedArrayInit:
3643 case SK_PassByIndirectCopyRestore:
3644 case SK_PassByIndirectRestore:
3645 case SK_ProduceObjCObject:
3646 case SK_StdInitializerList:
3647 case SK_StdInitializerListConstructorCall:
3648 case SK_OCLSamplerInit:
3649 case SK_OCLZeroOpaqueType:
3650 case SK_ParenthesizedListInit:
3651 break;
3652
3653 case SK_ConversionSequence:
3654 case SK_ConversionSequenceNoNarrowing:
3655 delete ICS;
3656 }
3657 }
3658
isDirectReferenceBinding() const3659 bool InitializationSequence::isDirectReferenceBinding() const {
3660 // There can be some lvalue adjustments after the SK_BindReference step.
3661 for (const Step &S : llvm::reverse(Steps)) {
3662 if (S.Kind == SK_BindReference)
3663 return true;
3664 if (S.Kind == SK_BindReferenceToTemporary)
3665 return false;
3666 }
3667 return false;
3668 }
3669
isAmbiguous() const3670 bool InitializationSequence::isAmbiguous() const {
3671 if (!Failed())
3672 return false;
3673
3674 switch (getFailureKind()) {
3675 case FK_TooManyInitsForReference:
3676 case FK_ParenthesizedListInitForReference:
3677 case FK_ArrayNeedsInitList:
3678 case FK_ArrayNeedsInitListOrStringLiteral:
3679 case FK_ArrayNeedsInitListOrWideStringLiteral:
3680 case FK_NarrowStringIntoWideCharArray:
3681 case FK_WideStringIntoCharArray:
3682 case FK_IncompatWideStringIntoWideChar:
3683 case FK_PlainStringIntoUTF8Char:
3684 case FK_UTF8StringIntoPlainChar:
3685 case FK_AddressOfOverloadFailed: // FIXME: Could do better
3686 case FK_NonConstLValueReferenceBindingToTemporary:
3687 case FK_NonConstLValueReferenceBindingToBitfield:
3688 case FK_NonConstLValueReferenceBindingToVectorElement:
3689 case FK_NonConstLValueReferenceBindingToMatrixElement:
3690 case FK_NonConstLValueReferenceBindingToUnrelated:
3691 case FK_RValueReferenceBindingToLValue:
3692 case FK_ReferenceAddrspaceMismatchTemporary:
3693 case FK_ReferenceInitDropsQualifiers:
3694 case FK_ReferenceInitFailed:
3695 case FK_ConversionFailed:
3696 case FK_ConversionFromPropertyFailed:
3697 case FK_TooManyInitsForScalar:
3698 case FK_ParenthesizedListInitForScalar:
3699 case FK_ReferenceBindingToInitList:
3700 case FK_InitListBadDestinationType:
3701 case FK_DefaultInitOfConst:
3702 case FK_Incomplete:
3703 case FK_ArrayTypeMismatch:
3704 case FK_NonConstantArrayInit:
3705 case FK_ListInitializationFailed:
3706 case FK_VariableLengthArrayHasInitializer:
3707 case FK_PlaceholderType:
3708 case FK_ExplicitConstructor:
3709 case FK_AddressOfUnaddressableFunction:
3710 case FK_ParenthesizedListInitFailed:
3711 case FK_DesignatedInitForNonAggregate:
3712 return false;
3713
3714 case FK_ReferenceInitOverloadFailed:
3715 case FK_UserConversionOverloadFailed:
3716 case FK_ConstructorOverloadFailed:
3717 case FK_ListConstructorOverloadFailed:
3718 return FailedOverloadResult == OR_Ambiguous;
3719 }
3720
3721 llvm_unreachable("Invalid EntityKind!");
3722 }
3723
isConstructorInitialization() const3724 bool InitializationSequence::isConstructorInitialization() const {
3725 return !Steps.empty() && Steps.back().Kind == SK_ConstructorInitialization;
3726 }
3727
3728 void
3729 InitializationSequence
AddAddressOverloadResolutionStep(FunctionDecl * Function,DeclAccessPair Found,bool HadMultipleCandidates)3730 ::AddAddressOverloadResolutionStep(FunctionDecl *Function,
3731 DeclAccessPair Found,
3732 bool HadMultipleCandidates) {
3733 Step S;
3734 S.Kind = SK_ResolveAddressOfOverloadedFunction;
3735 S.Type = Function->getType();
3736 S.Function.HadMultipleCandidates = HadMultipleCandidates;
3737 S.Function.Function = Function;
3738 S.Function.FoundDecl = Found;
3739 Steps.push_back(S);
3740 }
3741
AddDerivedToBaseCastStep(QualType BaseType,ExprValueKind VK)3742 void InitializationSequence::AddDerivedToBaseCastStep(QualType BaseType,
3743 ExprValueKind VK) {
3744 Step S;
3745 switch (VK) {
3746 case VK_PRValue:
3747 S.Kind = SK_CastDerivedToBasePRValue;
3748 break;
3749 case VK_XValue: S.Kind = SK_CastDerivedToBaseXValue; break;
3750 case VK_LValue: S.Kind = SK_CastDerivedToBaseLValue; break;
3751 }
3752 S.Type = BaseType;
3753 Steps.push_back(S);
3754 }
3755
AddReferenceBindingStep(QualType T,bool BindingTemporary)3756 void InitializationSequence::AddReferenceBindingStep(QualType T,
3757 bool BindingTemporary) {
3758 Step S;
3759 S.Kind = BindingTemporary? SK_BindReferenceToTemporary : SK_BindReference;
3760 S.Type = T;
3761 Steps.push_back(S);
3762 }
3763
AddFinalCopy(QualType T)3764 void InitializationSequence::AddFinalCopy(QualType T) {
3765 Step S;
3766 S.Kind = SK_FinalCopy;
3767 S.Type = T;
3768 Steps.push_back(S);
3769 }
3770
AddExtraneousCopyToTemporary(QualType T)3771 void InitializationSequence::AddExtraneousCopyToTemporary(QualType T) {
3772 Step S;
3773 S.Kind = SK_ExtraneousCopyToTemporary;
3774 S.Type = T;
3775 Steps.push_back(S);
3776 }
3777
3778 void
AddUserConversionStep(FunctionDecl * Function,DeclAccessPair FoundDecl,QualType T,bool HadMultipleCandidates)3779 InitializationSequence::AddUserConversionStep(FunctionDecl *Function,
3780 DeclAccessPair FoundDecl,
3781 QualType T,
3782 bool HadMultipleCandidates) {
3783 Step S;
3784 S.Kind = SK_UserConversion;
3785 S.Type = T;
3786 S.Function.HadMultipleCandidates = HadMultipleCandidates;
3787 S.Function.Function = Function;
3788 S.Function.FoundDecl = FoundDecl;
3789 Steps.push_back(S);
3790 }
3791
AddQualificationConversionStep(QualType Ty,ExprValueKind VK)3792 void InitializationSequence::AddQualificationConversionStep(QualType Ty,
3793 ExprValueKind VK) {
3794 Step S;
3795 S.Kind = SK_QualificationConversionPRValue; // work around a gcc warning
3796 switch (VK) {
3797 case VK_PRValue:
3798 S.Kind = SK_QualificationConversionPRValue;
3799 break;
3800 case VK_XValue:
3801 S.Kind = SK_QualificationConversionXValue;
3802 break;
3803 case VK_LValue:
3804 S.Kind = SK_QualificationConversionLValue;
3805 break;
3806 }
3807 S.Type = Ty;
3808 Steps.push_back(S);
3809 }
3810
AddFunctionReferenceConversionStep(QualType Ty)3811 void InitializationSequence::AddFunctionReferenceConversionStep(QualType Ty) {
3812 Step S;
3813 S.Kind = SK_FunctionReferenceConversion;
3814 S.Type = Ty;
3815 Steps.push_back(S);
3816 }
3817
AddAtomicConversionStep(QualType Ty)3818 void InitializationSequence::AddAtomicConversionStep(QualType Ty) {
3819 Step S;
3820 S.Kind = SK_AtomicConversion;
3821 S.Type = Ty;
3822 Steps.push_back(S);
3823 }
3824
AddConversionSequenceStep(const ImplicitConversionSequence & ICS,QualType T,bool TopLevelOfInitList)3825 void InitializationSequence::AddConversionSequenceStep(
3826 const ImplicitConversionSequence &ICS, QualType T,
3827 bool TopLevelOfInitList) {
3828 Step S;
3829 S.Kind = TopLevelOfInitList ? SK_ConversionSequenceNoNarrowing
3830 : SK_ConversionSequence;
3831 S.Type = T;
3832 S.ICS = new ImplicitConversionSequence(ICS);
3833 Steps.push_back(S);
3834 }
3835
AddListInitializationStep(QualType T)3836 void InitializationSequence::AddListInitializationStep(QualType T) {
3837 Step S;
3838 S.Kind = SK_ListInitialization;
3839 S.Type = T;
3840 Steps.push_back(S);
3841 }
3842
AddConstructorInitializationStep(DeclAccessPair FoundDecl,CXXConstructorDecl * Constructor,QualType T,bool HadMultipleCandidates,bool FromInitList,bool AsInitList)3843 void InitializationSequence::AddConstructorInitializationStep(
3844 DeclAccessPair FoundDecl, CXXConstructorDecl *Constructor, QualType T,
3845 bool HadMultipleCandidates, bool FromInitList, bool AsInitList) {
3846 Step S;
3847 S.Kind = FromInitList ? AsInitList ? SK_StdInitializerListConstructorCall
3848 : SK_ConstructorInitializationFromList
3849 : SK_ConstructorInitialization;
3850 S.Type = T;
3851 S.Function.HadMultipleCandidates = HadMultipleCandidates;
3852 S.Function.Function = Constructor;
3853 S.Function.FoundDecl = FoundDecl;
3854 Steps.push_back(S);
3855 }
3856
AddZeroInitializationStep(QualType T)3857 void InitializationSequence::AddZeroInitializationStep(QualType T) {
3858 Step S;
3859 S.Kind = SK_ZeroInitialization;
3860 S.Type = T;
3861 Steps.push_back(S);
3862 }
3863
AddCAssignmentStep(QualType T)3864 void InitializationSequence::AddCAssignmentStep(QualType T) {
3865 Step S;
3866 S.Kind = SK_CAssignment;
3867 S.Type = T;
3868 Steps.push_back(S);
3869 }
3870
AddStringInitStep(QualType T)3871 void InitializationSequence::AddStringInitStep(QualType T) {
3872 Step S;
3873 S.Kind = SK_StringInit;
3874 S.Type = T;
3875 Steps.push_back(S);
3876 }
3877
AddObjCObjectConversionStep(QualType T)3878 void InitializationSequence::AddObjCObjectConversionStep(QualType T) {
3879 Step S;
3880 S.Kind = SK_ObjCObjectConversion;
3881 S.Type = T;
3882 Steps.push_back(S);
3883 }
3884
AddArrayInitStep(QualType T,bool IsGNUExtension)3885 void InitializationSequence::AddArrayInitStep(QualType T, bool IsGNUExtension) {
3886 Step S;
3887 S.Kind = IsGNUExtension ? SK_GNUArrayInit : SK_ArrayInit;
3888 S.Type = T;
3889 Steps.push_back(S);
3890 }
3891
AddArrayInitLoopStep(QualType T,QualType EltT)3892 void InitializationSequence::AddArrayInitLoopStep(QualType T, QualType EltT) {
3893 Step S;
3894 S.Kind = SK_ArrayLoopIndex;
3895 S.Type = EltT;
3896 Steps.insert(Steps.begin(), S);
3897
3898 S.Kind = SK_ArrayLoopInit;
3899 S.Type = T;
3900 Steps.push_back(S);
3901 }
3902
AddParenthesizedArrayInitStep(QualType T)3903 void InitializationSequence::AddParenthesizedArrayInitStep(QualType T) {
3904 Step S;
3905 S.Kind = SK_ParenthesizedArrayInit;
3906 S.Type = T;
3907 Steps.push_back(S);
3908 }
3909
AddPassByIndirectCopyRestoreStep(QualType type,bool shouldCopy)3910 void InitializationSequence::AddPassByIndirectCopyRestoreStep(QualType type,
3911 bool shouldCopy) {
3912 Step s;
3913 s.Kind = (shouldCopy ? SK_PassByIndirectCopyRestore
3914 : SK_PassByIndirectRestore);
3915 s.Type = type;
3916 Steps.push_back(s);
3917 }
3918
AddProduceObjCObjectStep(QualType T)3919 void InitializationSequence::AddProduceObjCObjectStep(QualType T) {
3920 Step S;
3921 S.Kind = SK_ProduceObjCObject;
3922 S.Type = T;
3923 Steps.push_back(S);
3924 }
3925
AddStdInitializerListConstructionStep(QualType T)3926 void InitializationSequence::AddStdInitializerListConstructionStep(QualType T) {
3927 Step S;
3928 S.Kind = SK_StdInitializerList;
3929 S.Type = T;
3930 Steps.push_back(S);
3931 }
3932
AddOCLSamplerInitStep(QualType T)3933 void InitializationSequence::AddOCLSamplerInitStep(QualType T) {
3934 Step S;
3935 S.Kind = SK_OCLSamplerInit;
3936 S.Type = T;
3937 Steps.push_back(S);
3938 }
3939
AddOCLZeroOpaqueTypeStep(QualType T)3940 void InitializationSequence::AddOCLZeroOpaqueTypeStep(QualType T) {
3941 Step S;
3942 S.Kind = SK_OCLZeroOpaqueType;
3943 S.Type = T;
3944 Steps.push_back(S);
3945 }
3946
AddParenthesizedListInitStep(QualType T)3947 void InitializationSequence::AddParenthesizedListInitStep(QualType T) {
3948 Step S;
3949 S.Kind = SK_ParenthesizedListInit;
3950 S.Type = T;
3951 Steps.push_back(S);
3952 }
3953
RewrapReferenceInitList(QualType T,InitListExpr * Syntactic)3954 void InitializationSequence::RewrapReferenceInitList(QualType T,
3955 InitListExpr *Syntactic) {
3956 assert(Syntactic->getNumInits() == 1 &&
3957 "Can only rewrap trivial init lists.");
3958 Step S;
3959 S.Kind = SK_UnwrapInitList;
3960 S.Type = Syntactic->getInit(0)->getType();
3961 Steps.insert(Steps.begin(), S);
3962
3963 S.Kind = SK_RewrapInitList;
3964 S.Type = T;
3965 S.WrappingSyntacticList = Syntactic;
3966 Steps.push_back(S);
3967 }
3968
SetOverloadFailure(FailureKind Failure,OverloadingResult Result)3969 void InitializationSequence::SetOverloadFailure(FailureKind Failure,
3970 OverloadingResult Result) {
3971 setSequenceKind(FailedSequence);
3972 this->Failure = Failure;
3973 this->FailedOverloadResult = Result;
3974 }
3975
3976 //===----------------------------------------------------------------------===//
3977 // Attempt initialization
3978 //===----------------------------------------------------------------------===//
3979
3980 /// Tries to add a zero initializer. Returns true if that worked.
3981 static bool
maybeRecoverWithZeroInitialization(Sema & S,InitializationSequence & Sequence,const InitializedEntity & Entity)3982 maybeRecoverWithZeroInitialization(Sema &S, InitializationSequence &Sequence,
3983 const InitializedEntity &Entity) {
3984 if (Entity.getKind() != InitializedEntity::EK_Variable)
3985 return false;
3986
3987 VarDecl *VD = cast<VarDecl>(Entity.getDecl());
3988 if (VD->getInit() || VD->getEndLoc().isMacroID())
3989 return false;
3990
3991 QualType VariableTy = VD->getType().getCanonicalType();
3992 SourceLocation Loc = S.getLocForEndOfToken(VD->getEndLoc());
3993 std::string Init = S.getFixItZeroInitializerForType(VariableTy, Loc);
3994 if (!Init.empty()) {
3995 Sequence.AddZeroInitializationStep(Entity.getType());
3996 Sequence.SetZeroInitializationFixit(Init, Loc);
3997 return true;
3998 }
3999 return false;
4000 }
4001
MaybeProduceObjCObject(Sema & S,InitializationSequence & Sequence,const InitializedEntity & Entity)4002 static void MaybeProduceObjCObject(Sema &S,
4003 InitializationSequence &Sequence,
4004 const InitializedEntity &Entity) {
4005 if (!S.getLangOpts().ObjCAutoRefCount) return;
4006
4007 /// When initializing a parameter, produce the value if it's marked
4008 /// __attribute__((ns_consumed)).
4009 if (Entity.isParameterKind()) {
4010 if (!Entity.isParameterConsumed())
4011 return;
4012
4013 assert(Entity.getType()->isObjCRetainableType() &&
4014 "consuming an object of unretainable type?");
4015 Sequence.AddProduceObjCObjectStep(Entity.getType());
4016
4017 /// When initializing a return value, if the return type is a
4018 /// retainable type, then returns need to immediately retain the
4019 /// object. If an autorelease is required, it will be done at the
4020 /// last instant.
4021 } else if (Entity.getKind() == InitializedEntity::EK_Result ||
4022 Entity.getKind() == InitializedEntity::EK_StmtExprResult) {
4023 if (!Entity.getType()->isObjCRetainableType())
4024 return;
4025
4026 Sequence.AddProduceObjCObjectStep(Entity.getType());
4027 }
4028 }
4029
4030 static void TryListInitialization(Sema &S,
4031 const InitializedEntity &Entity,
4032 const InitializationKind &Kind,
4033 InitListExpr *InitList,
4034 InitializationSequence &Sequence,
4035 bool TreatUnavailableAsInvalid);
4036
4037 /// When initializing from init list via constructor, handle
4038 /// initialization of an object of type std::initializer_list<T>.
4039 ///
4040 /// \return true if we have handled initialization of an object of type
4041 /// std::initializer_list<T>, false otherwise.
TryInitializerListConstruction(Sema & S,InitListExpr * List,QualType DestType,InitializationSequence & Sequence,bool TreatUnavailableAsInvalid)4042 static bool TryInitializerListConstruction(Sema &S,
4043 InitListExpr *List,
4044 QualType DestType,
4045 InitializationSequence &Sequence,
4046 bool TreatUnavailableAsInvalid) {
4047 QualType E;
4048 if (!S.isStdInitializerList(DestType, &E))
4049 return false;
4050
4051 if (!S.isCompleteType(List->getExprLoc(), E)) {
4052 Sequence.setIncompleteTypeFailure(E);
4053 return true;
4054 }
4055
4056 // Try initializing a temporary array from the init list.
4057 QualType ArrayType = S.Context.getConstantArrayType(
4058 E.withConst(),
4059 llvm::APInt(S.Context.getTypeSize(S.Context.getSizeType()),
4060 List->getNumInits()),
4061 nullptr, clang::ArraySizeModifier::Normal, 0);
4062 InitializedEntity HiddenArray =
4063 InitializedEntity::InitializeTemporary(ArrayType);
4064 InitializationKind Kind = InitializationKind::CreateDirectList(
4065 List->getExprLoc(), List->getBeginLoc(), List->getEndLoc());
4066 TryListInitialization(S, HiddenArray, Kind, List, Sequence,
4067 TreatUnavailableAsInvalid);
4068 if (Sequence)
4069 Sequence.AddStdInitializerListConstructionStep(DestType);
4070 return true;
4071 }
4072
4073 /// Determine if the constructor has the signature of a copy or move
4074 /// constructor for the type T of the class in which it was found. That is,
4075 /// determine if its first parameter is of type T or reference to (possibly
4076 /// cv-qualified) T.
hasCopyOrMoveCtorParam(ASTContext & Ctx,const ConstructorInfo & Info)4077 static bool hasCopyOrMoveCtorParam(ASTContext &Ctx,
4078 const ConstructorInfo &Info) {
4079 if (Info.Constructor->getNumParams() == 0)
4080 return false;
4081
4082 QualType ParmT =
4083 Info.Constructor->getParamDecl(0)->getType().getNonReferenceType();
4084 QualType ClassT =
4085 Ctx.getRecordType(cast<CXXRecordDecl>(Info.FoundDecl->getDeclContext()));
4086
4087 return Ctx.hasSameUnqualifiedType(ParmT, ClassT);
4088 }
4089
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 RequireActualConstructor,bool SecondStepOfCopyInit=false)4090 static OverloadingResult ResolveConstructorOverload(
4091 Sema &S, SourceLocation DeclLoc, MultiExprArg Args,
4092 OverloadCandidateSet &CandidateSet, QualType DestType,
4093 DeclContext::lookup_result Ctors, OverloadCandidateSet::iterator &Best,
4094 bool CopyInitializing, bool AllowExplicit, bool OnlyListConstructors,
4095 bool IsListInit, bool RequireActualConstructor,
4096 bool SecondStepOfCopyInit = false) {
4097 CandidateSet.clear(OverloadCandidateSet::CSK_InitByConstructor);
4098 CandidateSet.setDestAS(DestType.getQualifiers().getAddressSpace());
4099
4100 for (NamedDecl *D : Ctors) {
4101 auto Info = getConstructorInfo(D);
4102 if (!Info.Constructor || Info.Constructor->isInvalidDecl())
4103 continue;
4104
4105 if (OnlyListConstructors && !S.isInitListConstructor(Info.Constructor))
4106 continue;
4107
4108 // C++11 [over.best.ics]p4:
4109 // ... and the constructor or user-defined conversion function is a
4110 // candidate by
4111 // - 13.3.1.3, when the argument is the temporary in the second step
4112 // of a class copy-initialization, or
4113 // - 13.3.1.4, 13.3.1.5, or 13.3.1.6 (in all cases), [not handled here]
4114 // - the second phase of 13.3.1.7 when the initializer list has exactly
4115 // one element that is itself an initializer list, and the target is
4116 // the first parameter of a constructor of class X, and the conversion
4117 // is to X or reference to (possibly cv-qualified X),
4118 // user-defined conversion sequences are not considered.
4119 bool SuppressUserConversions =
4120 SecondStepOfCopyInit ||
4121 (IsListInit && Args.size() == 1 && isa<InitListExpr>(Args[0]) &&
4122 hasCopyOrMoveCtorParam(S.Context, Info));
4123
4124 if (Info.ConstructorTmpl)
4125 S.AddTemplateOverloadCandidate(
4126 Info.ConstructorTmpl, Info.FoundDecl,
4127 /*ExplicitArgs*/ nullptr, Args, CandidateSet, SuppressUserConversions,
4128 /*PartialOverloading=*/false, AllowExplicit);
4129 else {
4130 // C++ [over.match.copy]p1:
4131 // - When initializing a temporary to be bound to the first parameter
4132 // of a constructor [for type T] that takes a reference to possibly
4133 // cv-qualified T as its first argument, called with a single
4134 // argument in the context of direct-initialization, explicit
4135 // conversion functions are also considered.
4136 // FIXME: What if a constructor template instantiates to such a signature?
4137 bool AllowExplicitConv = AllowExplicit && !CopyInitializing &&
4138 Args.size() == 1 &&
4139 hasCopyOrMoveCtorParam(S.Context, Info);
4140 S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, Args,
4141 CandidateSet, SuppressUserConversions,
4142 /*PartialOverloading=*/false, AllowExplicit,
4143 AllowExplicitConv);
4144 }
4145 }
4146
4147 // FIXME: Work around a bug in C++17 guaranteed copy elision.
4148 //
4149 // When initializing an object of class type T by constructor
4150 // ([over.match.ctor]) or by list-initialization ([over.match.list])
4151 // from a single expression of class type U, conversion functions of
4152 // U that convert to the non-reference type cv T are candidates.
4153 // Explicit conversion functions are only candidates during
4154 // direct-initialization.
4155 //
4156 // Note: SecondStepOfCopyInit is only ever true in this case when
4157 // evaluating whether to produce a C++98 compatibility warning.
4158 if (S.getLangOpts().CPlusPlus17 && Args.size() == 1 &&
4159 !RequireActualConstructor && !SecondStepOfCopyInit) {
4160 Expr *Initializer = Args[0];
4161 auto *SourceRD = Initializer->getType()->getAsCXXRecordDecl();
4162 if (SourceRD && S.isCompleteType(DeclLoc, Initializer->getType())) {
4163 const auto &Conversions = SourceRD->getVisibleConversionFunctions();
4164 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
4165 NamedDecl *D = *I;
4166 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
4167 D = D->getUnderlyingDecl();
4168
4169 FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
4170 CXXConversionDecl *Conv;
4171 if (ConvTemplate)
4172 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
4173 else
4174 Conv = cast<CXXConversionDecl>(D);
4175
4176 if (ConvTemplate)
4177 S.AddTemplateConversionCandidate(
4178 ConvTemplate, I.getPair(), ActingDC, Initializer, DestType,
4179 CandidateSet, AllowExplicit, AllowExplicit,
4180 /*AllowResultConversion*/ false);
4181 else
4182 S.AddConversionCandidate(Conv, I.getPair(), ActingDC, Initializer,
4183 DestType, CandidateSet, AllowExplicit,
4184 AllowExplicit,
4185 /*AllowResultConversion*/ false);
4186 }
4187 }
4188 }
4189
4190 // Perform overload resolution and return the result.
4191 return CandidateSet.BestViableFunction(S, DeclLoc, Best);
4192 }
4193
4194 /// Attempt initialization by constructor (C++ [dcl.init]), which
4195 /// enumerates the constructors of the initialized entity and performs overload
4196 /// resolution to select the best.
4197 /// \param DestType The destination class type.
4198 /// \param DestArrayType The destination type, which is either DestType or
4199 /// a (possibly multidimensional) array of DestType.
4200 /// \param IsListInit Is this list-initialization?
4201 /// \param IsInitListCopy Is this non-list-initialization resulting from a
4202 /// list-initialization from {x} where x is the same
4203 /// 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)4204 static void TryConstructorInitialization(Sema &S,
4205 const InitializedEntity &Entity,
4206 const InitializationKind &Kind,
4207 MultiExprArg Args, QualType DestType,
4208 QualType DestArrayType,
4209 InitializationSequence &Sequence,
4210 bool IsListInit = false,
4211 bool IsInitListCopy = false) {
4212 assert(((!IsListInit && !IsInitListCopy) ||
4213 (Args.size() == 1 && isa<InitListExpr>(Args[0]))) &&
4214 "IsListInit/IsInitListCopy must come with a single initializer list "
4215 "argument.");
4216 InitListExpr *ILE =
4217 (IsListInit || IsInitListCopy) ? cast<InitListExpr>(Args[0]) : nullptr;
4218 MultiExprArg UnwrappedArgs =
4219 ILE ? MultiExprArg(ILE->getInits(), ILE->getNumInits()) : Args;
4220
4221 // The type we're constructing needs to be complete.
4222 if (!S.isCompleteType(Kind.getLocation(), DestType)) {
4223 Sequence.setIncompleteTypeFailure(DestType);
4224 return;
4225 }
4226
4227 bool RequireActualConstructor =
4228 !(Entity.getKind() != InitializedEntity::EK_Base &&
4229 Entity.getKind() != InitializedEntity::EK_Delegating &&
4230 Entity.getKind() !=
4231 InitializedEntity::EK_LambdaToBlockConversionBlockElement);
4232
4233 // C++17 [dcl.init]p17:
4234 // - If the initializer expression is a prvalue and the cv-unqualified
4235 // version of the source type is the same class as the class of the
4236 // destination, the initializer expression is used to initialize the
4237 // destination object.
4238 // Per DR (no number yet), this does not apply when initializing a base
4239 // class or delegating to another constructor from a mem-initializer.
4240 // ObjC++: Lambda captured by the block in the lambda to block conversion
4241 // should avoid copy elision.
4242 if (S.getLangOpts().CPlusPlus17 && !RequireActualConstructor &&
4243 UnwrappedArgs.size() == 1 && UnwrappedArgs[0]->isPRValue() &&
4244 S.Context.hasSameUnqualifiedType(UnwrappedArgs[0]->getType(), DestType)) {
4245 // Convert qualifications if necessary.
4246 Sequence.AddQualificationConversionStep(DestType, VK_PRValue);
4247 if (ILE)
4248 Sequence.RewrapReferenceInitList(DestType, ILE);
4249 return;
4250 }
4251
4252 const RecordType *DestRecordType = DestType->getAs<RecordType>();
4253 assert(DestRecordType && "Constructor initialization requires record type");
4254 CXXRecordDecl *DestRecordDecl
4255 = cast<CXXRecordDecl>(DestRecordType->getDecl());
4256
4257 // Build the candidate set directly in the initialization sequence
4258 // structure, so that it will persist if we fail.
4259 OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
4260
4261 // Determine whether we are allowed to call explicit constructors or
4262 // explicit conversion operators.
4263 bool AllowExplicit = Kind.AllowExplicit() || IsListInit;
4264 bool CopyInitialization = Kind.getKind() == InitializationKind::IK_Copy;
4265
4266 // - Otherwise, if T is a class type, constructors are considered. The
4267 // applicable constructors are enumerated, and the best one is chosen
4268 // through overload resolution.
4269 DeclContext::lookup_result Ctors = S.LookupConstructors(DestRecordDecl);
4270
4271 OverloadingResult Result = OR_No_Viable_Function;
4272 OverloadCandidateSet::iterator Best;
4273 bool AsInitializerList = false;
4274
4275 // C++11 [over.match.list]p1, per DR1467:
4276 // When objects of non-aggregate type T are list-initialized, such that
4277 // 8.5.4 [dcl.init.list] specifies that overload resolution is performed
4278 // according to the rules in this section, overload resolution selects
4279 // the constructor in two phases:
4280 //
4281 // - Initially, the candidate functions are the initializer-list
4282 // constructors of the class T and the argument list consists of the
4283 // initializer list as a single argument.
4284 if (IsListInit) {
4285 AsInitializerList = true;
4286
4287 // If the initializer list has no elements and T has a default constructor,
4288 // the first phase is omitted.
4289 if (!(UnwrappedArgs.empty() && S.LookupDefaultConstructor(DestRecordDecl)))
4290 Result = ResolveConstructorOverload(
4291 S, Kind.getLocation(), Args, CandidateSet, DestType, Ctors, Best,
4292 CopyInitialization, AllowExplicit,
4293 /*OnlyListConstructors=*/true, IsListInit, RequireActualConstructor);
4294 }
4295
4296 // C++11 [over.match.list]p1:
4297 // - If no viable initializer-list constructor is found, overload resolution
4298 // is performed again, where the candidate functions are all the
4299 // constructors of the class T and the argument list consists of the
4300 // elements of the initializer list.
4301 if (Result == OR_No_Viable_Function) {
4302 AsInitializerList = false;
4303 Result = ResolveConstructorOverload(
4304 S, Kind.getLocation(), UnwrappedArgs, CandidateSet, DestType, Ctors,
4305 Best, CopyInitialization, AllowExplicit,
4306 /*OnlyListConstructors=*/false, IsListInit, RequireActualConstructor);
4307 }
4308 if (Result) {
4309 Sequence.SetOverloadFailure(
4310 IsListInit ? InitializationSequence::FK_ListConstructorOverloadFailed
4311 : InitializationSequence::FK_ConstructorOverloadFailed,
4312 Result);
4313
4314 if (Result != OR_Deleted)
4315 return;
4316 }
4317
4318 bool HadMultipleCandidates = (CandidateSet.size() > 1);
4319
4320 // In C++17, ResolveConstructorOverload can select a conversion function
4321 // instead of a constructor.
4322 if (auto *CD = dyn_cast<CXXConversionDecl>(Best->Function)) {
4323 // Add the user-defined conversion step that calls the conversion function.
4324 QualType ConvType = CD->getConversionType();
4325 assert(S.Context.hasSameUnqualifiedType(ConvType, DestType) &&
4326 "should not have selected this conversion function");
4327 Sequence.AddUserConversionStep(CD, Best->FoundDecl, ConvType,
4328 HadMultipleCandidates);
4329 if (!S.Context.hasSameType(ConvType, DestType))
4330 Sequence.AddQualificationConversionStep(DestType, VK_PRValue);
4331 if (IsListInit)
4332 Sequence.RewrapReferenceInitList(Entity.getType(), ILE);
4333 return;
4334 }
4335
4336 CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
4337 if (Result != OR_Deleted) {
4338 // C++11 [dcl.init]p6:
4339 // If a program calls for the default initialization of an object
4340 // of a const-qualified type T, T shall be a class type with a
4341 // user-provided default constructor.
4342 // C++ core issue 253 proposal:
4343 // If the implicit default constructor initializes all subobjects, no
4344 // initializer should be required.
4345 // The 253 proposal is for example needed to process libstdc++ headers
4346 // in 5.x.
4347 if (Kind.getKind() == InitializationKind::IK_Default &&
4348 Entity.getType().isConstQualified()) {
4349 if (!CtorDecl->getParent()->allowConstDefaultInit()) {
4350 if (!maybeRecoverWithZeroInitialization(S, Sequence, Entity))
4351 Sequence.SetFailed(InitializationSequence::FK_DefaultInitOfConst);
4352 return;
4353 }
4354 }
4355
4356 // C++11 [over.match.list]p1:
4357 // In copy-list-initialization, if an explicit constructor is chosen, the
4358 // initializer is ill-formed.
4359 if (IsListInit && !Kind.AllowExplicit() && CtorDecl->isExplicit()) {
4360 Sequence.SetFailed(InitializationSequence::FK_ExplicitConstructor);
4361 return;
4362 }
4363 }
4364
4365 // [class.copy.elision]p3:
4366 // In some copy-initialization contexts, a two-stage overload resolution
4367 // is performed.
4368 // If the first overload resolution selects a deleted function, we also
4369 // need the initialization sequence to decide whether to perform the second
4370 // overload resolution.
4371 // For deleted functions in other contexts, there is no need to get the
4372 // initialization sequence.
4373 if (Result == OR_Deleted && Kind.getKind() != InitializationKind::IK_Copy)
4374 return;
4375
4376 // Add the constructor initialization step. Any cv-qualification conversion is
4377 // subsumed by the initialization.
4378 Sequence.AddConstructorInitializationStep(
4379 Best->FoundDecl, CtorDecl, DestArrayType, HadMultipleCandidates,
4380 IsListInit | IsInitListCopy, AsInitializerList);
4381 }
4382
4383 static bool
ResolveOverloadedFunctionForReferenceBinding(Sema & S,Expr * Initializer,QualType & SourceType,QualType & UnqualifiedSourceType,QualType UnqualifiedTargetType,InitializationSequence & Sequence)4384 ResolveOverloadedFunctionForReferenceBinding(Sema &S,
4385 Expr *Initializer,
4386 QualType &SourceType,
4387 QualType &UnqualifiedSourceType,
4388 QualType UnqualifiedTargetType,
4389 InitializationSequence &Sequence) {
4390 if (S.Context.getCanonicalType(UnqualifiedSourceType) ==
4391 S.Context.OverloadTy) {
4392 DeclAccessPair Found;
4393 bool HadMultipleCandidates = false;
4394 if (FunctionDecl *Fn
4395 = S.ResolveAddressOfOverloadedFunction(Initializer,
4396 UnqualifiedTargetType,
4397 false, Found,
4398 &HadMultipleCandidates)) {
4399 Sequence.AddAddressOverloadResolutionStep(Fn, Found,
4400 HadMultipleCandidates);
4401 SourceType = Fn->getType();
4402 UnqualifiedSourceType = SourceType.getUnqualifiedType();
4403 } else if (!UnqualifiedTargetType->isRecordType()) {
4404 Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
4405 return true;
4406 }
4407 }
4408 return false;
4409 }
4410
4411 static void TryReferenceInitializationCore(Sema &S,
4412 const InitializedEntity &Entity,
4413 const InitializationKind &Kind,
4414 Expr *Initializer,
4415 QualType cv1T1, QualType T1,
4416 Qualifiers T1Quals,
4417 QualType cv2T2, QualType T2,
4418 Qualifiers T2Quals,
4419 InitializationSequence &Sequence,
4420 bool TopLevelOfInitList);
4421
4422 static void TryValueInitialization(Sema &S,
4423 const InitializedEntity &Entity,
4424 const InitializationKind &Kind,
4425 InitializationSequence &Sequence,
4426 InitListExpr *InitList = nullptr);
4427
4428 /// Attempt list initialization of a reference.
TryReferenceListInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,InitListExpr * InitList,InitializationSequence & Sequence,bool TreatUnavailableAsInvalid)4429 static void TryReferenceListInitialization(Sema &S,
4430 const InitializedEntity &Entity,
4431 const InitializationKind &Kind,
4432 InitListExpr *InitList,
4433 InitializationSequence &Sequence,
4434 bool TreatUnavailableAsInvalid) {
4435 // First, catch C++03 where this isn't possible.
4436 if (!S.getLangOpts().CPlusPlus11) {
4437 Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
4438 return;
4439 }
4440 // Can't reference initialize a compound literal.
4441 if (Entity.getKind() == InitializedEntity::EK_CompoundLiteralInit) {
4442 Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
4443 return;
4444 }
4445
4446 QualType DestType = Entity.getType();
4447 QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
4448 Qualifiers T1Quals;
4449 QualType T1 = S.Context.getUnqualifiedArrayType(cv1T1, T1Quals);
4450
4451 // Reference initialization via an initializer list works thus:
4452 // If the initializer list consists of a single element that is
4453 // reference-related to the referenced type, bind directly to that element
4454 // (possibly creating temporaries).
4455 // Otherwise, initialize a temporary with the initializer list and
4456 // bind to that.
4457 if (InitList->getNumInits() == 1) {
4458 Expr *Initializer = InitList->getInit(0);
4459 QualType cv2T2 = S.getCompletedType(Initializer);
4460 Qualifiers T2Quals;
4461 QualType T2 = S.Context.getUnqualifiedArrayType(cv2T2, T2Quals);
4462
4463 // If this fails, creating a temporary wouldn't work either.
4464 if (ResolveOverloadedFunctionForReferenceBinding(S, Initializer, cv2T2, T2,
4465 T1, Sequence))
4466 return;
4467
4468 SourceLocation DeclLoc = Initializer->getBeginLoc();
4469 Sema::ReferenceCompareResult RefRelationship
4470 = S.CompareReferenceRelationship(DeclLoc, cv1T1, cv2T2);
4471 if (RefRelationship >= Sema::Ref_Related) {
4472 // Try to bind the reference here.
4473 TryReferenceInitializationCore(S, Entity, Kind, Initializer, cv1T1, T1,
4474 T1Quals, cv2T2, T2, T2Quals, Sequence,
4475 /*TopLevelOfInitList=*/true);
4476 if (Sequence)
4477 Sequence.RewrapReferenceInitList(cv1T1, InitList);
4478 return;
4479 }
4480
4481 // Update the initializer if we've resolved an overloaded function.
4482 if (Sequence.step_begin() != Sequence.step_end())
4483 Sequence.RewrapReferenceInitList(cv1T1, InitList);
4484 }
4485 // Perform address space compatibility check.
4486 QualType cv1T1IgnoreAS = cv1T1;
4487 if (T1Quals.hasAddressSpace()) {
4488 Qualifiers T2Quals;
4489 (void)S.Context.getUnqualifiedArrayType(InitList->getType(), T2Quals);
4490 if (!T1Quals.isAddressSpaceSupersetOf(T2Quals)) {
4491 Sequence.SetFailed(
4492 InitializationSequence::FK_ReferenceInitDropsQualifiers);
4493 return;
4494 }
4495 // Ignore address space of reference type at this point and perform address
4496 // space conversion after the reference binding step.
4497 cv1T1IgnoreAS =
4498 S.Context.getQualifiedType(T1, T1Quals.withoutAddressSpace());
4499 }
4500 // Not reference-related. Create a temporary and bind to that.
4501 InitializedEntity TempEntity =
4502 InitializedEntity::InitializeTemporary(cv1T1IgnoreAS);
4503
4504 TryListInitialization(S, TempEntity, Kind, InitList, Sequence,
4505 TreatUnavailableAsInvalid);
4506 if (Sequence) {
4507 if (DestType->isRValueReferenceType() ||
4508 (T1Quals.hasConst() && !T1Quals.hasVolatile())) {
4509 if (S.getLangOpts().CPlusPlus20 &&
4510 isa<IncompleteArrayType>(T1->getUnqualifiedDesugaredType()) &&
4511 DestType->isRValueReferenceType()) {
4512 // C++20 [dcl.init.list]p3.10:
4513 // List-initialization of an object or reference of type T is defined as
4514 // follows:
4515 // ..., unless T is “reference to array of unknown bound of U”, in which
4516 // case the type of the prvalue is the type of x in the declaration U
4517 // x[] H, where H is the initializer list.
4518 Sequence.AddQualificationConversionStep(cv1T1, clang::VK_PRValue);
4519 }
4520 Sequence.AddReferenceBindingStep(cv1T1IgnoreAS,
4521 /*BindingTemporary=*/true);
4522 if (T1Quals.hasAddressSpace())
4523 Sequence.AddQualificationConversionStep(
4524 cv1T1, DestType->isRValueReferenceType() ? VK_XValue : VK_LValue);
4525 } else
4526 Sequence.SetFailed(
4527 InitializationSequence::FK_NonConstLValueReferenceBindingToTemporary);
4528 }
4529 }
4530
4531 /// Attempt list initialization (C++0x [dcl.init.list])
TryListInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,InitListExpr * InitList,InitializationSequence & Sequence,bool TreatUnavailableAsInvalid)4532 static void TryListInitialization(Sema &S,
4533 const InitializedEntity &Entity,
4534 const InitializationKind &Kind,
4535 InitListExpr *InitList,
4536 InitializationSequence &Sequence,
4537 bool TreatUnavailableAsInvalid) {
4538 QualType DestType = Entity.getType();
4539
4540 // C++ doesn't allow scalar initialization with more than one argument.
4541 // But C99 complex numbers are scalars and it makes sense there.
4542 if (S.getLangOpts().CPlusPlus && DestType->isScalarType() &&
4543 !DestType->isAnyComplexType() && InitList->getNumInits() > 1) {
4544 Sequence.SetFailed(InitializationSequence::FK_TooManyInitsForScalar);
4545 return;
4546 }
4547 if (DestType->isReferenceType()) {
4548 TryReferenceListInitialization(S, Entity, Kind, InitList, Sequence,
4549 TreatUnavailableAsInvalid);
4550 return;
4551 }
4552
4553 if (DestType->isRecordType() &&
4554 !S.isCompleteType(InitList->getBeginLoc(), DestType)) {
4555 Sequence.setIncompleteTypeFailure(DestType);
4556 return;
4557 }
4558
4559 // C++20 [dcl.init.list]p3:
4560 // - If the braced-init-list contains a designated-initializer-list, T shall
4561 // be an aggregate class. [...] Aggregate initialization is performed.
4562 //
4563 // We allow arrays here too in order to support array designators.
4564 //
4565 // FIXME: This check should precede the handling of reference initialization.
4566 // We follow other compilers in allowing things like 'Aggr &&a = {.x = 1};'
4567 // as a tentative DR resolution.
4568 bool IsDesignatedInit = InitList->hasDesignatedInit();
4569 if (!DestType->isAggregateType() && IsDesignatedInit) {
4570 Sequence.SetFailed(
4571 InitializationSequence::FK_DesignatedInitForNonAggregate);
4572 return;
4573 }
4574
4575 // C++11 [dcl.init.list]p3, per DR1467:
4576 // - If T is a class type and the initializer list has a single element of
4577 // type cv U, where U is T or a class derived from T, the object is
4578 // initialized from that element (by copy-initialization for
4579 // copy-list-initialization, or by direct-initialization for
4580 // direct-list-initialization).
4581 // - Otherwise, if T is a character array and the initializer list has a
4582 // single element that is an appropriately-typed string literal
4583 // (8.5.2 [dcl.init.string]), initialization is performed as described
4584 // in that section.
4585 // - Otherwise, if T is an aggregate, [...] (continue below).
4586 if (S.getLangOpts().CPlusPlus11 && InitList->getNumInits() == 1 &&
4587 !IsDesignatedInit) {
4588 if (DestType->isRecordType()) {
4589 QualType InitType = InitList->getInit(0)->getType();
4590 if (S.Context.hasSameUnqualifiedType(InitType, DestType) ||
4591 S.IsDerivedFrom(InitList->getBeginLoc(), InitType, DestType)) {
4592 Expr *InitListAsExpr = InitList;
4593 TryConstructorInitialization(S, Entity, Kind, InitListAsExpr, DestType,
4594 DestType, Sequence,
4595 /*InitListSyntax*/false,
4596 /*IsInitListCopy*/true);
4597 return;
4598 }
4599 }
4600 if (const ArrayType *DestAT = S.Context.getAsArrayType(DestType)) {
4601 Expr *SubInit[1] = {InitList->getInit(0)};
4602 if (!isa<VariableArrayType>(DestAT) &&
4603 IsStringInit(SubInit[0], DestAT, S.Context) == SIF_None) {
4604 InitializationKind SubKind =
4605 Kind.getKind() == InitializationKind::IK_DirectList
4606 ? InitializationKind::CreateDirect(Kind.getLocation(),
4607 InitList->getLBraceLoc(),
4608 InitList->getRBraceLoc())
4609 : Kind;
4610 Sequence.InitializeFrom(S, Entity, SubKind, SubInit,
4611 /*TopLevelOfInitList*/ true,
4612 TreatUnavailableAsInvalid);
4613
4614 // TryStringLiteralInitialization() (in InitializeFrom()) will fail if
4615 // the element is not an appropriately-typed string literal, in which
4616 // case we should proceed as in C++11 (below).
4617 if (Sequence) {
4618 Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
4619 return;
4620 }
4621 }
4622 }
4623 }
4624
4625 // C++11 [dcl.init.list]p3:
4626 // - If T is an aggregate, aggregate initialization is performed.
4627 if ((DestType->isRecordType() && !DestType->isAggregateType()) ||
4628 (S.getLangOpts().CPlusPlus11 &&
4629 S.isStdInitializerList(DestType, nullptr) && !IsDesignatedInit)) {
4630 if (S.getLangOpts().CPlusPlus11) {
4631 // - Otherwise, if the initializer list has no elements and T is a
4632 // class type with a default constructor, the object is
4633 // value-initialized.
4634 if (InitList->getNumInits() == 0) {
4635 CXXRecordDecl *RD = DestType->getAsCXXRecordDecl();
4636 if (S.LookupDefaultConstructor(RD)) {
4637 TryValueInitialization(S, Entity, Kind, Sequence, InitList);
4638 return;
4639 }
4640 }
4641
4642 // - Otherwise, if T is a specialization of std::initializer_list<E>,
4643 // an initializer_list object constructed [...]
4644 if (TryInitializerListConstruction(S, InitList, DestType, Sequence,
4645 TreatUnavailableAsInvalid))
4646 return;
4647
4648 // - Otherwise, if T is a class type, constructors are considered.
4649 Expr *InitListAsExpr = InitList;
4650 TryConstructorInitialization(S, Entity, Kind, InitListAsExpr, DestType,
4651 DestType, Sequence, /*InitListSyntax*/true);
4652 } else
4653 Sequence.SetFailed(InitializationSequence::FK_InitListBadDestinationType);
4654 return;
4655 }
4656
4657 if (S.getLangOpts().CPlusPlus && !DestType->isAggregateType() &&
4658 InitList->getNumInits() == 1) {
4659 Expr *E = InitList->getInit(0);
4660
4661 // - Otherwise, if T is an enumeration with a fixed underlying type,
4662 // the initializer-list has a single element v, and the initialization
4663 // is direct-list-initialization, the object is initialized with the
4664 // value T(v); if a narrowing conversion is required to convert v to
4665 // the underlying type of T, the program is ill-formed.
4666 auto *ET = DestType->getAs<EnumType>();
4667 if (S.getLangOpts().CPlusPlus17 &&
4668 Kind.getKind() == InitializationKind::IK_DirectList &&
4669 ET && ET->getDecl()->isFixed() &&
4670 !S.Context.hasSameUnqualifiedType(E->getType(), DestType) &&
4671 (E->getType()->isIntegralOrUnscopedEnumerationType() ||
4672 E->getType()->isFloatingType())) {
4673 // There are two ways that T(v) can work when T is an enumeration type.
4674 // If there is either an implicit conversion sequence from v to T or
4675 // a conversion function that can convert from v to T, then we use that.
4676 // Otherwise, if v is of integral, unscoped enumeration, or floating-point
4677 // type, it is converted to the enumeration type via its underlying type.
4678 // There is no overlap possible between these two cases (except when the
4679 // source value is already of the destination type), and the first
4680 // case is handled by the general case for single-element lists below.
4681 ImplicitConversionSequence ICS;
4682 ICS.setStandard();
4683 ICS.Standard.setAsIdentityConversion();
4684 if (!E->isPRValue())
4685 ICS.Standard.First = ICK_Lvalue_To_Rvalue;
4686 // If E is of a floating-point type, then the conversion is ill-formed
4687 // due to narrowing, but go through the motions in order to produce the
4688 // right diagnostic.
4689 ICS.Standard.Second = E->getType()->isFloatingType()
4690 ? ICK_Floating_Integral
4691 : ICK_Integral_Conversion;
4692 ICS.Standard.setFromType(E->getType());
4693 ICS.Standard.setToType(0, E->getType());
4694 ICS.Standard.setToType(1, DestType);
4695 ICS.Standard.setToType(2, DestType);
4696 Sequence.AddConversionSequenceStep(ICS, ICS.Standard.getToType(2),
4697 /*TopLevelOfInitList*/true);
4698 Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
4699 return;
4700 }
4701
4702 // - Otherwise, if the initializer list has a single element of type E
4703 // [...references are handled above...], the object or reference is
4704 // initialized from that element (by copy-initialization for
4705 // copy-list-initialization, or by direct-initialization for
4706 // direct-list-initialization); if a narrowing conversion is required
4707 // to convert the element to T, the program is ill-formed.
4708 //
4709 // Per core-24034, this is direct-initialization if we were performing
4710 // direct-list-initialization and copy-initialization otherwise.
4711 // We can't use InitListChecker for this, because it always performs
4712 // copy-initialization. This only matters if we might use an 'explicit'
4713 // conversion operator, or for the special case conversion of nullptr_t to
4714 // bool, so we only need to handle those cases.
4715 //
4716 // FIXME: Why not do this in all cases?
4717 Expr *Init = InitList->getInit(0);
4718 if (Init->getType()->isRecordType() ||
4719 (Init->getType()->isNullPtrType() && DestType->isBooleanType())) {
4720 InitializationKind SubKind =
4721 Kind.getKind() == InitializationKind::IK_DirectList
4722 ? InitializationKind::CreateDirect(Kind.getLocation(),
4723 InitList->getLBraceLoc(),
4724 InitList->getRBraceLoc())
4725 : Kind;
4726 Expr *SubInit[1] = { Init };
4727 Sequence.InitializeFrom(S, Entity, SubKind, SubInit,
4728 /*TopLevelOfInitList*/true,
4729 TreatUnavailableAsInvalid);
4730 if (Sequence)
4731 Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
4732 return;
4733 }
4734 }
4735
4736 InitListChecker CheckInitList(S, Entity, InitList,
4737 DestType, /*VerifyOnly=*/true, TreatUnavailableAsInvalid);
4738 if (CheckInitList.HadError()) {
4739 Sequence.SetFailed(InitializationSequence::FK_ListInitializationFailed);
4740 return;
4741 }
4742
4743 // Add the list initialization step with the built init list.
4744 Sequence.AddListInitializationStep(DestType);
4745 }
4746
4747 /// Try a reference initialization that involves calling a conversion
4748 /// function.
TryRefInitWithConversionFunction(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,Expr * Initializer,bool AllowRValues,bool IsLValueRef,InitializationSequence & Sequence)4749 static OverloadingResult TryRefInitWithConversionFunction(
4750 Sema &S, const InitializedEntity &Entity, const InitializationKind &Kind,
4751 Expr *Initializer, bool AllowRValues, bool IsLValueRef,
4752 InitializationSequence &Sequence) {
4753 QualType DestType = Entity.getType();
4754 QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
4755 QualType T1 = cv1T1.getUnqualifiedType();
4756 QualType cv2T2 = Initializer->getType();
4757 QualType T2 = cv2T2.getUnqualifiedType();
4758
4759 assert(!S.CompareReferenceRelationship(Initializer->getBeginLoc(), T1, T2) &&
4760 "Must have incompatible references when binding via conversion");
4761
4762 // Build the candidate set directly in the initialization sequence
4763 // structure, so that it will persist if we fail.
4764 OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
4765 CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
4766
4767 // Determine whether we are allowed to call explicit conversion operators.
4768 // Note that none of [over.match.copy], [over.match.conv], nor
4769 // [over.match.ref] permit an explicit constructor to be chosen when
4770 // initializing a reference, not even for direct-initialization.
4771 bool AllowExplicitCtors = false;
4772 bool AllowExplicitConvs = Kind.allowExplicitConversionFunctionsInRefBinding();
4773
4774 const RecordType *T1RecordType = nullptr;
4775 if (AllowRValues && (T1RecordType = T1->getAs<RecordType>()) &&
4776 S.isCompleteType(Kind.getLocation(), T1)) {
4777 // The type we're converting to is a class type. Enumerate its constructors
4778 // to see if there is a suitable conversion.
4779 CXXRecordDecl *T1RecordDecl = cast<CXXRecordDecl>(T1RecordType->getDecl());
4780
4781 for (NamedDecl *D : S.LookupConstructors(T1RecordDecl)) {
4782 auto Info = getConstructorInfo(D);
4783 if (!Info.Constructor)
4784 continue;
4785
4786 if (!Info.Constructor->isInvalidDecl() &&
4787 Info.Constructor->isConvertingConstructor(/*AllowExplicit*/true)) {
4788 if (Info.ConstructorTmpl)
4789 S.AddTemplateOverloadCandidate(
4790 Info.ConstructorTmpl, Info.FoundDecl,
4791 /*ExplicitArgs*/ nullptr, Initializer, CandidateSet,
4792 /*SuppressUserConversions=*/true,
4793 /*PartialOverloading*/ false, AllowExplicitCtors);
4794 else
4795 S.AddOverloadCandidate(
4796 Info.Constructor, Info.FoundDecl, Initializer, CandidateSet,
4797 /*SuppressUserConversions=*/true,
4798 /*PartialOverloading*/ false, AllowExplicitCtors);
4799 }
4800 }
4801 }
4802 if (T1RecordType && T1RecordType->getDecl()->isInvalidDecl())
4803 return OR_No_Viable_Function;
4804
4805 const RecordType *T2RecordType = nullptr;
4806 if ((T2RecordType = T2->getAs<RecordType>()) &&
4807 S.isCompleteType(Kind.getLocation(), T2)) {
4808 // The type we're converting from is a class type, enumerate its conversion
4809 // functions.
4810 CXXRecordDecl *T2RecordDecl = cast<CXXRecordDecl>(T2RecordType->getDecl());
4811
4812 const auto &Conversions = T2RecordDecl->getVisibleConversionFunctions();
4813 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
4814 NamedDecl *D = *I;
4815 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
4816 if (isa<UsingShadowDecl>(D))
4817 D = cast<UsingShadowDecl>(D)->getTargetDecl();
4818
4819 FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
4820 CXXConversionDecl *Conv;
4821 if (ConvTemplate)
4822 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
4823 else
4824 Conv = cast<CXXConversionDecl>(D);
4825
4826 // If the conversion function doesn't return a reference type,
4827 // it can't be considered for this conversion unless we're allowed to
4828 // consider rvalues.
4829 // FIXME: Do we need to make sure that we only consider conversion
4830 // candidates with reference-compatible results? That might be needed to
4831 // break recursion.
4832 if ((AllowRValues ||
4833 Conv->getConversionType()->isLValueReferenceType())) {
4834 if (ConvTemplate)
4835 S.AddTemplateConversionCandidate(
4836 ConvTemplate, I.getPair(), ActingDC, Initializer, DestType,
4837 CandidateSet,
4838 /*AllowObjCConversionOnExplicit=*/false, AllowExplicitConvs);
4839 else
4840 S.AddConversionCandidate(
4841 Conv, I.getPair(), ActingDC, Initializer, DestType, CandidateSet,
4842 /*AllowObjCConversionOnExplicit=*/false, AllowExplicitConvs);
4843 }
4844 }
4845 }
4846 if (T2RecordType && T2RecordType->getDecl()->isInvalidDecl())
4847 return OR_No_Viable_Function;
4848
4849 SourceLocation DeclLoc = Initializer->getBeginLoc();
4850
4851 // Perform overload resolution. If it fails, return the failed result.
4852 OverloadCandidateSet::iterator Best;
4853 if (OverloadingResult Result
4854 = CandidateSet.BestViableFunction(S, DeclLoc, Best))
4855 return Result;
4856
4857 FunctionDecl *Function = Best->Function;
4858 // This is the overload that will be used for this initialization step if we
4859 // use this initialization. Mark it as referenced.
4860 Function->setReferenced();
4861
4862 // Compute the returned type and value kind of the conversion.
4863 QualType cv3T3;
4864 if (isa<CXXConversionDecl>(Function))
4865 cv3T3 = Function->getReturnType();
4866 else
4867 cv3T3 = T1;
4868
4869 ExprValueKind VK = VK_PRValue;
4870 if (cv3T3->isLValueReferenceType())
4871 VK = VK_LValue;
4872 else if (const auto *RRef = cv3T3->getAs<RValueReferenceType>())
4873 VK = RRef->getPointeeType()->isFunctionType() ? VK_LValue : VK_XValue;
4874 cv3T3 = cv3T3.getNonLValueExprType(S.Context);
4875
4876 // Add the user-defined conversion step.
4877 bool HadMultipleCandidates = (CandidateSet.size() > 1);
4878 Sequence.AddUserConversionStep(Function, Best->FoundDecl, cv3T3,
4879 HadMultipleCandidates);
4880
4881 // Determine whether we'll need to perform derived-to-base adjustments or
4882 // other conversions.
4883 Sema::ReferenceConversions RefConv;
4884 Sema::ReferenceCompareResult NewRefRelationship =
4885 S.CompareReferenceRelationship(DeclLoc, T1, cv3T3, &RefConv);
4886
4887 // Add the final conversion sequence, if necessary.
4888 if (NewRefRelationship == Sema::Ref_Incompatible) {
4889 assert(!isa<CXXConstructorDecl>(Function) &&
4890 "should not have conversion after constructor");
4891
4892 ImplicitConversionSequence ICS;
4893 ICS.setStandard();
4894 ICS.Standard = Best->FinalConversion;
4895 Sequence.AddConversionSequenceStep(ICS, ICS.Standard.getToType(2));
4896
4897 // Every implicit conversion results in a prvalue, except for a glvalue
4898 // derived-to-base conversion, which we handle below.
4899 cv3T3 = ICS.Standard.getToType(2);
4900 VK = VK_PRValue;
4901 }
4902
4903 // If the converted initializer is a prvalue, its type T4 is adjusted to
4904 // type "cv1 T4" and the temporary materialization conversion is applied.
4905 //
4906 // We adjust the cv-qualifications to match the reference regardless of
4907 // whether we have a prvalue so that the AST records the change. In this
4908 // case, T4 is "cv3 T3".
4909 QualType cv1T4 = S.Context.getQualifiedType(cv3T3, cv1T1.getQualifiers());
4910 if (cv1T4.getQualifiers() != cv3T3.getQualifiers())
4911 Sequence.AddQualificationConversionStep(cv1T4, VK);
4912 Sequence.AddReferenceBindingStep(cv1T4, VK == VK_PRValue);
4913 VK = IsLValueRef ? VK_LValue : VK_XValue;
4914
4915 if (RefConv & Sema::ReferenceConversions::DerivedToBase)
4916 Sequence.AddDerivedToBaseCastStep(cv1T1, VK);
4917 else if (RefConv & Sema::ReferenceConversions::ObjC)
4918 Sequence.AddObjCObjectConversionStep(cv1T1);
4919 else if (RefConv & Sema::ReferenceConversions::Function)
4920 Sequence.AddFunctionReferenceConversionStep(cv1T1);
4921 else if (RefConv & Sema::ReferenceConversions::Qualification) {
4922 if (!S.Context.hasSameType(cv1T4, cv1T1))
4923 Sequence.AddQualificationConversionStep(cv1T1, VK);
4924 }
4925
4926 return OR_Success;
4927 }
4928
4929 static void CheckCXX98CompatAccessibleCopy(Sema &S,
4930 const InitializedEntity &Entity,
4931 Expr *CurInitExpr);
4932
4933 /// Attempt reference initialization (C++0x [dcl.init.ref])
TryReferenceInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,Expr * Initializer,InitializationSequence & Sequence,bool TopLevelOfInitList)4934 static void TryReferenceInitialization(Sema &S, const InitializedEntity &Entity,
4935 const InitializationKind &Kind,
4936 Expr *Initializer,
4937 InitializationSequence &Sequence,
4938 bool TopLevelOfInitList) {
4939 QualType DestType = Entity.getType();
4940 QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
4941 Qualifiers T1Quals;
4942 QualType T1 = S.Context.getUnqualifiedArrayType(cv1T1, T1Quals);
4943 QualType cv2T2 = S.getCompletedType(Initializer);
4944 Qualifiers T2Quals;
4945 QualType T2 = S.Context.getUnqualifiedArrayType(cv2T2, T2Quals);
4946
4947 // If the initializer is the address of an overloaded function, try
4948 // to resolve the overloaded function. If all goes well, T2 is the
4949 // type of the resulting function.
4950 if (ResolveOverloadedFunctionForReferenceBinding(S, Initializer, cv2T2, T2,
4951 T1, Sequence))
4952 return;
4953
4954 // Delegate everything else to a subfunction.
4955 TryReferenceInitializationCore(S, Entity, Kind, Initializer, cv1T1, T1,
4956 T1Quals, cv2T2, T2, T2Quals, Sequence,
4957 TopLevelOfInitList);
4958 }
4959
4960 /// Determine whether an expression is a non-referenceable glvalue (one to
4961 /// which a reference can never bind). Attempting to bind a reference to
4962 /// such a glvalue will always create a temporary.
isNonReferenceableGLValue(Expr * E)4963 static bool isNonReferenceableGLValue(Expr *E) {
4964 return E->refersToBitField() || E->refersToVectorElement() ||
4965 E->refersToMatrixElement();
4966 }
4967
4968 /// Reference initialization without resolving overloaded functions.
4969 ///
4970 /// We also can get here in C if we call a builtin which is declared as
4971 /// 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,bool TopLevelOfInitList)4972 static void TryReferenceInitializationCore(Sema &S,
4973 const InitializedEntity &Entity,
4974 const InitializationKind &Kind,
4975 Expr *Initializer,
4976 QualType cv1T1, QualType T1,
4977 Qualifiers T1Quals,
4978 QualType cv2T2, QualType T2,
4979 Qualifiers T2Quals,
4980 InitializationSequence &Sequence,
4981 bool TopLevelOfInitList) {
4982 QualType DestType = Entity.getType();
4983 SourceLocation DeclLoc = Initializer->getBeginLoc();
4984
4985 // Compute some basic properties of the types and the initializer.
4986 bool isLValueRef = DestType->isLValueReferenceType();
4987 bool isRValueRef = !isLValueRef;
4988 Expr::Classification InitCategory = Initializer->Classify(S.Context);
4989
4990 Sema::ReferenceConversions RefConv;
4991 Sema::ReferenceCompareResult RefRelationship =
4992 S.CompareReferenceRelationship(DeclLoc, cv1T1, cv2T2, &RefConv);
4993
4994 // C++0x [dcl.init.ref]p5:
4995 // A reference to type "cv1 T1" is initialized by an expression of type
4996 // "cv2 T2" as follows:
4997 //
4998 // - If the reference is an lvalue reference and the initializer
4999 // expression
5000 // Note the analogous bullet points for rvalue refs to functions. Because
5001 // there are no function rvalues in C++, rvalue refs to functions are treated
5002 // like lvalue refs.
5003 OverloadingResult ConvOvlResult = OR_Success;
5004 bool T1Function = T1->isFunctionType();
5005 if (isLValueRef || T1Function) {
5006 if (InitCategory.isLValue() && !isNonReferenceableGLValue(Initializer) &&
5007 (RefRelationship == Sema::Ref_Compatible ||
5008 (Kind.isCStyleOrFunctionalCast() &&
5009 RefRelationship == Sema::Ref_Related))) {
5010 // - is an lvalue (but is not a bit-field), and "cv1 T1" is
5011 // reference-compatible with "cv2 T2," or
5012 if (RefConv & (Sema::ReferenceConversions::DerivedToBase |
5013 Sema::ReferenceConversions::ObjC)) {
5014 // If we're converting the pointee, add any qualifiers first;
5015 // these qualifiers must all be top-level, so just convert to "cv1 T2".
5016 if (RefConv & (Sema::ReferenceConversions::Qualification))
5017 Sequence.AddQualificationConversionStep(
5018 S.Context.getQualifiedType(T2, T1Quals),
5019 Initializer->getValueKind());
5020 if (RefConv & Sema::ReferenceConversions::DerivedToBase)
5021 Sequence.AddDerivedToBaseCastStep(cv1T1, VK_LValue);
5022 else
5023 Sequence.AddObjCObjectConversionStep(cv1T1);
5024 } else if (RefConv & Sema::ReferenceConversions::Qualification) {
5025 // Perform a (possibly multi-level) qualification conversion.
5026 Sequence.AddQualificationConversionStep(cv1T1,
5027 Initializer->getValueKind());
5028 } else if (RefConv & Sema::ReferenceConversions::Function) {
5029 Sequence.AddFunctionReferenceConversionStep(cv1T1);
5030 }
5031
5032 // We only create a temporary here when binding a reference to a
5033 // bit-field or vector element. Those cases are't supposed to be
5034 // handled by this bullet, but the outcome is the same either way.
5035 Sequence.AddReferenceBindingStep(cv1T1, false);
5036 return;
5037 }
5038
5039 // - has a class type (i.e., T2 is a class type), where T1 is not
5040 // reference-related to T2, and can be implicitly converted to an
5041 // lvalue of type "cv3 T3," where "cv1 T1" is reference-compatible
5042 // with "cv3 T3" (this conversion is selected by enumerating the
5043 // applicable conversion functions (13.3.1.6) and choosing the best
5044 // one through overload resolution (13.3)),
5045 // If we have an rvalue ref to function type here, the rhs must be
5046 // an rvalue. DR1287 removed the "implicitly" here.
5047 if (RefRelationship == Sema::Ref_Incompatible && T2->isRecordType() &&
5048 (isLValueRef || InitCategory.isRValue())) {
5049 if (S.getLangOpts().CPlusPlus) {
5050 // Try conversion functions only for C++.
5051 ConvOvlResult = TryRefInitWithConversionFunction(
5052 S, Entity, Kind, Initializer, /*AllowRValues*/ isRValueRef,
5053 /*IsLValueRef*/ isLValueRef, Sequence);
5054 if (ConvOvlResult == OR_Success)
5055 return;
5056 if (ConvOvlResult != OR_No_Viable_Function)
5057 Sequence.SetOverloadFailure(
5058 InitializationSequence::FK_ReferenceInitOverloadFailed,
5059 ConvOvlResult);
5060 } else {
5061 ConvOvlResult = OR_No_Viable_Function;
5062 }
5063 }
5064 }
5065
5066 // - Otherwise, the reference shall be an lvalue reference to a
5067 // non-volatile const type (i.e., cv1 shall be const), or the reference
5068 // shall be an rvalue reference.
5069 // For address spaces, we interpret this to mean that an addr space
5070 // of a reference "cv1 T1" is a superset of addr space of "cv2 T2".
5071 if (isLValueRef && !(T1Quals.hasConst() && !T1Quals.hasVolatile() &&
5072 T1Quals.isAddressSpaceSupersetOf(T2Quals))) {
5073 if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy)
5074 Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
5075 else if (ConvOvlResult && !Sequence.getFailedCandidateSet().empty())
5076 Sequence.SetOverloadFailure(
5077 InitializationSequence::FK_ReferenceInitOverloadFailed,
5078 ConvOvlResult);
5079 else if (!InitCategory.isLValue())
5080 Sequence.SetFailed(
5081 T1Quals.isAddressSpaceSupersetOf(T2Quals)
5082 ? InitializationSequence::
5083 FK_NonConstLValueReferenceBindingToTemporary
5084 : InitializationSequence::FK_ReferenceInitDropsQualifiers);
5085 else {
5086 InitializationSequence::FailureKind FK;
5087 switch (RefRelationship) {
5088 case Sema::Ref_Compatible:
5089 if (Initializer->refersToBitField())
5090 FK = InitializationSequence::
5091 FK_NonConstLValueReferenceBindingToBitfield;
5092 else if (Initializer->refersToVectorElement())
5093 FK = InitializationSequence::
5094 FK_NonConstLValueReferenceBindingToVectorElement;
5095 else if (Initializer->refersToMatrixElement())
5096 FK = InitializationSequence::
5097 FK_NonConstLValueReferenceBindingToMatrixElement;
5098 else
5099 llvm_unreachable("unexpected kind of compatible initializer");
5100 break;
5101 case Sema::Ref_Related:
5102 FK = InitializationSequence::FK_ReferenceInitDropsQualifiers;
5103 break;
5104 case Sema::Ref_Incompatible:
5105 FK = InitializationSequence::
5106 FK_NonConstLValueReferenceBindingToUnrelated;
5107 break;
5108 }
5109 Sequence.SetFailed(FK);
5110 }
5111 return;
5112 }
5113
5114 // - If the initializer expression
5115 // - is an
5116 // [<=14] xvalue (but not a bit-field), class prvalue, array prvalue, or
5117 // [1z] rvalue (but not a bit-field) or
5118 // function lvalue and "cv1 T1" is reference-compatible with "cv2 T2"
5119 //
5120 // Note: functions are handled above and below rather than here...
5121 if (!T1Function &&
5122 (RefRelationship == Sema::Ref_Compatible ||
5123 (Kind.isCStyleOrFunctionalCast() &&
5124 RefRelationship == Sema::Ref_Related)) &&
5125 ((InitCategory.isXValue() && !isNonReferenceableGLValue(Initializer)) ||
5126 (InitCategory.isPRValue() &&
5127 (S.getLangOpts().CPlusPlus17 || T2->isRecordType() ||
5128 T2->isArrayType())))) {
5129 ExprValueKind ValueKind = InitCategory.isXValue() ? VK_XValue : VK_PRValue;
5130 if (InitCategory.isPRValue() && T2->isRecordType()) {
5131 // The corresponding bullet in C++03 [dcl.init.ref]p5 gives the
5132 // compiler the freedom to perform a copy here or bind to the
5133 // object, while C++0x requires that we bind directly to the
5134 // object. Hence, we always bind to the object without making an
5135 // extra copy. However, in C++03 requires that we check for the
5136 // presence of a suitable copy constructor:
5137 //
5138 // The constructor that would be used to make the copy shall
5139 // be callable whether or not the copy is actually done.
5140 if (!S.getLangOpts().CPlusPlus11 && !S.getLangOpts().MicrosoftExt)
5141 Sequence.AddExtraneousCopyToTemporary(cv2T2);
5142 else if (S.getLangOpts().CPlusPlus11)
5143 CheckCXX98CompatAccessibleCopy(S, Entity, Initializer);
5144 }
5145
5146 // C++1z [dcl.init.ref]/5.2.1.2:
5147 // If the converted initializer is a prvalue, its type T4 is adjusted
5148 // to type "cv1 T4" and the temporary materialization conversion is
5149 // applied.
5150 // Postpone address space conversions to after the temporary materialization
5151 // conversion to allow creating temporaries in the alloca address space.
5152 auto T1QualsIgnoreAS = T1Quals;
5153 auto T2QualsIgnoreAS = T2Quals;
5154 if (T1Quals.getAddressSpace() != T2Quals.getAddressSpace()) {
5155 T1QualsIgnoreAS.removeAddressSpace();
5156 T2QualsIgnoreAS.removeAddressSpace();
5157 }
5158 QualType cv1T4 = S.Context.getQualifiedType(cv2T2, T1QualsIgnoreAS);
5159 if (T1QualsIgnoreAS != T2QualsIgnoreAS)
5160 Sequence.AddQualificationConversionStep(cv1T4, ValueKind);
5161 Sequence.AddReferenceBindingStep(cv1T4, ValueKind == VK_PRValue);
5162 ValueKind = isLValueRef ? VK_LValue : VK_XValue;
5163 // Add addr space conversion if required.
5164 if (T1Quals.getAddressSpace() != T2Quals.getAddressSpace()) {
5165 auto T4Quals = cv1T4.getQualifiers();
5166 T4Quals.addAddressSpace(T1Quals.getAddressSpace());
5167 QualType cv1T4WithAS = S.Context.getQualifiedType(T2, T4Quals);
5168 Sequence.AddQualificationConversionStep(cv1T4WithAS, ValueKind);
5169 cv1T4 = cv1T4WithAS;
5170 }
5171
5172 // In any case, the reference is bound to the resulting glvalue (or to
5173 // an appropriate base class subobject).
5174 if (RefConv & Sema::ReferenceConversions::DerivedToBase)
5175 Sequence.AddDerivedToBaseCastStep(cv1T1, ValueKind);
5176 else if (RefConv & Sema::ReferenceConversions::ObjC)
5177 Sequence.AddObjCObjectConversionStep(cv1T1);
5178 else if (RefConv & Sema::ReferenceConversions::Qualification) {
5179 if (!S.Context.hasSameType(cv1T4, cv1T1))
5180 Sequence.AddQualificationConversionStep(cv1T1, ValueKind);
5181 }
5182 return;
5183 }
5184
5185 // - has a class type (i.e., T2 is a class type), where T1 is not
5186 // reference-related to T2, and can be implicitly converted to an
5187 // xvalue, class prvalue, or function lvalue of type "cv3 T3",
5188 // where "cv1 T1" is reference-compatible with "cv3 T3",
5189 //
5190 // DR1287 removes the "implicitly" here.
5191 if (T2->isRecordType()) {
5192 if (RefRelationship == Sema::Ref_Incompatible) {
5193 ConvOvlResult = TryRefInitWithConversionFunction(
5194 S, Entity, Kind, Initializer, /*AllowRValues*/ true,
5195 /*IsLValueRef*/ isLValueRef, Sequence);
5196 if (ConvOvlResult)
5197 Sequence.SetOverloadFailure(
5198 InitializationSequence::FK_ReferenceInitOverloadFailed,
5199 ConvOvlResult);
5200
5201 return;
5202 }
5203
5204 if (RefRelationship == Sema::Ref_Compatible &&
5205 isRValueRef && InitCategory.isLValue()) {
5206 Sequence.SetFailed(
5207 InitializationSequence::FK_RValueReferenceBindingToLValue);
5208 return;
5209 }
5210
5211 Sequence.SetFailed(InitializationSequence::FK_ReferenceInitDropsQualifiers);
5212 return;
5213 }
5214
5215 // - Otherwise, a temporary of type "cv1 T1" is created and initialized
5216 // from the initializer expression using the rules for a non-reference
5217 // copy-initialization (8.5). The reference is then bound to the
5218 // temporary. [...]
5219
5220 // Ignore address space of reference type at this point and perform address
5221 // space conversion after the reference binding step.
5222 QualType cv1T1IgnoreAS =
5223 T1Quals.hasAddressSpace()
5224 ? S.Context.getQualifiedType(T1, T1Quals.withoutAddressSpace())
5225 : cv1T1;
5226
5227 InitializedEntity TempEntity =
5228 InitializedEntity::InitializeTemporary(cv1T1IgnoreAS);
5229
5230 // FIXME: Why do we use an implicit conversion here rather than trying
5231 // copy-initialization?
5232 ImplicitConversionSequence ICS
5233 = S.TryImplicitConversion(Initializer, TempEntity.getType(),
5234 /*SuppressUserConversions=*/false,
5235 Sema::AllowedExplicit::None,
5236 /*FIXME:InOverloadResolution=*/false,
5237 /*CStyle=*/Kind.isCStyleOrFunctionalCast(),
5238 /*AllowObjCWritebackConversion=*/false);
5239
5240 if (ICS.isBad()) {
5241 // FIXME: Use the conversion function set stored in ICS to turn
5242 // this into an overloading ambiguity diagnostic. However, we need
5243 // to keep that set as an OverloadCandidateSet rather than as some
5244 // other kind of set.
5245 if (ConvOvlResult && !Sequence.getFailedCandidateSet().empty())
5246 Sequence.SetOverloadFailure(
5247 InitializationSequence::FK_ReferenceInitOverloadFailed,
5248 ConvOvlResult);
5249 else if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy)
5250 Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
5251 else
5252 Sequence.SetFailed(InitializationSequence::FK_ReferenceInitFailed);
5253 return;
5254 } else {
5255 Sequence.AddConversionSequenceStep(ICS, TempEntity.getType(),
5256 TopLevelOfInitList);
5257 }
5258
5259 // [...] If T1 is reference-related to T2, cv1 must be the
5260 // same cv-qualification as, or greater cv-qualification
5261 // than, cv2; otherwise, the program is ill-formed.
5262 unsigned T1CVRQuals = T1Quals.getCVRQualifiers();
5263 unsigned T2CVRQuals = T2Quals.getCVRQualifiers();
5264 if (RefRelationship == Sema::Ref_Related &&
5265 ((T1CVRQuals | T2CVRQuals) != T1CVRQuals ||
5266 !T1Quals.isAddressSpaceSupersetOf(T2Quals))) {
5267 Sequence.SetFailed(InitializationSequence::FK_ReferenceInitDropsQualifiers);
5268 return;
5269 }
5270
5271 // [...] If T1 is reference-related to T2 and the reference is an rvalue
5272 // reference, the initializer expression shall not be an lvalue.
5273 if (RefRelationship >= Sema::Ref_Related && !isLValueRef &&
5274 InitCategory.isLValue()) {
5275 Sequence.SetFailed(
5276 InitializationSequence::FK_RValueReferenceBindingToLValue);
5277 return;
5278 }
5279
5280 Sequence.AddReferenceBindingStep(cv1T1IgnoreAS, /*BindingTemporary=*/true);
5281
5282 if (T1Quals.hasAddressSpace()) {
5283 if (!Qualifiers::isAddressSpaceSupersetOf(T1Quals.getAddressSpace(),
5284 LangAS::Default)) {
5285 Sequence.SetFailed(
5286 InitializationSequence::FK_ReferenceAddrspaceMismatchTemporary);
5287 return;
5288 }
5289 Sequence.AddQualificationConversionStep(cv1T1, isLValueRef ? VK_LValue
5290 : VK_XValue);
5291 }
5292 }
5293
5294 /// Attempt character array initialization from a string literal
5295 /// (C++ [dcl.init.string], C99 6.7.8).
TryStringLiteralInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,Expr * Initializer,InitializationSequence & Sequence)5296 static void TryStringLiteralInitialization(Sema &S,
5297 const InitializedEntity &Entity,
5298 const InitializationKind &Kind,
5299 Expr *Initializer,
5300 InitializationSequence &Sequence) {
5301 Sequence.AddStringInitStep(Entity.getType());
5302 }
5303
5304 /// Attempt value initialization (C++ [dcl.init]p7).
TryValueInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,InitializationSequence & Sequence,InitListExpr * InitList)5305 static void TryValueInitialization(Sema &S,
5306 const InitializedEntity &Entity,
5307 const InitializationKind &Kind,
5308 InitializationSequence &Sequence,
5309 InitListExpr *InitList) {
5310 assert((!InitList || InitList->getNumInits() == 0) &&
5311 "Shouldn't use value-init for non-empty init lists");
5312
5313 // C++98 [dcl.init]p5, C++11 [dcl.init]p7:
5314 //
5315 // To value-initialize an object of type T means:
5316 QualType T = Entity.getType();
5317
5318 // -- if T is an array type, then each element is value-initialized;
5319 T = S.Context.getBaseElementType(T);
5320
5321 if (const RecordType *RT = T->getAs<RecordType>()) {
5322 if (CXXRecordDecl *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
5323 bool NeedZeroInitialization = true;
5324 // C++98:
5325 // -- if T is a class type (clause 9) with a user-declared constructor
5326 // (12.1), then the default constructor for T is called (and the
5327 // initialization is ill-formed if T has no accessible default
5328 // constructor);
5329 // C++11:
5330 // -- if T is a class type (clause 9) with either no default constructor
5331 // (12.1 [class.ctor]) or a default constructor that is user-provided
5332 // or deleted, then the object is default-initialized;
5333 //
5334 // Note that the C++11 rule is the same as the C++98 rule if there are no
5335 // defaulted or deleted constructors, so we just use it unconditionally.
5336 CXXConstructorDecl *CD = S.LookupDefaultConstructor(ClassDecl);
5337 if (!CD || !CD->getCanonicalDecl()->isDefaulted() || CD->isDeleted())
5338 NeedZeroInitialization = false;
5339
5340 // -- if T is a (possibly cv-qualified) non-union class type without a
5341 // user-provided or deleted default constructor, then the object is
5342 // zero-initialized and, if T has a non-trivial default constructor,
5343 // default-initialized;
5344 // The 'non-union' here was removed by DR1502. The 'non-trivial default
5345 // constructor' part was removed by DR1507.
5346 if (NeedZeroInitialization)
5347 Sequence.AddZeroInitializationStep(Entity.getType());
5348
5349 // C++03:
5350 // -- if T is a non-union class type without a user-declared constructor,
5351 // then every non-static data member and base class component of T is
5352 // value-initialized;
5353 // [...] A program that calls for [...] value-initialization of an
5354 // entity of reference type is ill-formed.
5355 //
5356 // C++11 doesn't need this handling, because value-initialization does not
5357 // occur recursively there, and the implicit default constructor is
5358 // defined as deleted in the problematic cases.
5359 if (!S.getLangOpts().CPlusPlus11 &&
5360 ClassDecl->hasUninitializedReferenceMember()) {
5361 Sequence.SetFailed(InitializationSequence::FK_TooManyInitsForReference);
5362 return;
5363 }
5364
5365 // If this is list-value-initialization, pass the empty init list on when
5366 // building the constructor call. This affects the semantics of a few
5367 // things (such as whether an explicit default constructor can be called).
5368 Expr *InitListAsExpr = InitList;
5369 MultiExprArg Args(&InitListAsExpr, InitList ? 1 : 0);
5370 bool InitListSyntax = InitList;
5371
5372 // FIXME: Instead of creating a CXXConstructExpr of array type here,
5373 // wrap a class-typed CXXConstructExpr in an ArrayInitLoopExpr.
5374 return TryConstructorInitialization(
5375 S, Entity, Kind, Args, T, Entity.getType(), Sequence, InitListSyntax);
5376 }
5377 }
5378
5379 Sequence.AddZeroInitializationStep(Entity.getType());
5380 }
5381
5382 /// Attempt default initialization (C++ [dcl.init]p6).
TryDefaultInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,InitializationSequence & Sequence)5383 static void TryDefaultInitialization(Sema &S,
5384 const InitializedEntity &Entity,
5385 const InitializationKind &Kind,
5386 InitializationSequence &Sequence) {
5387 assert(Kind.getKind() == InitializationKind::IK_Default);
5388
5389 // C++ [dcl.init]p6:
5390 // To default-initialize an object of type T means:
5391 // - if T is an array type, each element is default-initialized;
5392 QualType DestType = S.Context.getBaseElementType(Entity.getType());
5393
5394 // - if T is a (possibly cv-qualified) class type (Clause 9), the default
5395 // constructor for T is called (and the initialization is ill-formed if
5396 // T has no accessible default constructor);
5397 if (DestType->isRecordType() && S.getLangOpts().CPlusPlus) {
5398 TryConstructorInitialization(S, Entity, Kind, std::nullopt, DestType,
5399 Entity.getType(), Sequence);
5400 return;
5401 }
5402
5403 // - otherwise, no initialization is performed.
5404
5405 // If a program calls for the default initialization of an object of
5406 // a const-qualified type T, T shall be a class type with a user-provided
5407 // default constructor.
5408 if (DestType.isConstQualified() && S.getLangOpts().CPlusPlus) {
5409 if (!maybeRecoverWithZeroInitialization(S, Sequence, Entity))
5410 Sequence.SetFailed(InitializationSequence::FK_DefaultInitOfConst);
5411 return;
5412 }
5413
5414 // If the destination type has a lifetime property, zero-initialize it.
5415 if (DestType.getQualifiers().hasObjCLifetime()) {
5416 Sequence.AddZeroInitializationStep(Entity.getType());
5417 return;
5418 }
5419 }
5420
TryOrBuildParenListInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,ArrayRef<Expr * > Args,InitializationSequence & Sequence,bool VerifyOnly,ExprResult * Result=nullptr)5421 static void TryOrBuildParenListInitialization(
5422 Sema &S, const InitializedEntity &Entity, const InitializationKind &Kind,
5423 ArrayRef<Expr *> Args, InitializationSequence &Sequence, bool VerifyOnly,
5424 ExprResult *Result = nullptr) {
5425 unsigned EntityIndexToProcess = 0;
5426 SmallVector<Expr *, 4> InitExprs;
5427 QualType ResultType;
5428 Expr *ArrayFiller = nullptr;
5429 FieldDecl *InitializedFieldInUnion = nullptr;
5430
5431 auto HandleInitializedEntity = [&](const InitializedEntity &SubEntity,
5432 const InitializationKind &SubKind,
5433 Expr *Arg, Expr **InitExpr = nullptr) {
5434 InitializationSequence IS = InitializationSequence(
5435 S, SubEntity, SubKind, Arg ? MultiExprArg(Arg) : std::nullopt);
5436
5437 if (IS.Failed()) {
5438 if (!VerifyOnly) {
5439 IS.Diagnose(S, SubEntity, SubKind, Arg ? ArrayRef(Arg) : std::nullopt);
5440 } else {
5441 Sequence.SetFailed(
5442 InitializationSequence::FK_ParenthesizedListInitFailed);
5443 }
5444
5445 return false;
5446 }
5447 if (!VerifyOnly) {
5448 ExprResult ER;
5449 ER = IS.Perform(S, SubEntity, SubKind,
5450 Arg ? MultiExprArg(Arg) : std::nullopt);
5451 if (InitExpr)
5452 *InitExpr = ER.get();
5453 else
5454 InitExprs.push_back(ER.get());
5455 }
5456 return true;
5457 };
5458
5459 if (const ArrayType *AT =
5460 S.getASTContext().getAsArrayType(Entity.getType())) {
5461 SmallVector<InitializedEntity, 4> ElementEntities;
5462 uint64_t ArrayLength;
5463 // C++ [dcl.init]p16.5
5464 // if the destination type is an array, the object is initialized as
5465 // follows. Let x1, . . . , xk be the elements of the expression-list. If
5466 // the destination type is an array of unknown bound, it is defined as
5467 // having k elements.
5468 if (const ConstantArrayType *CAT =
5469 S.getASTContext().getAsConstantArrayType(Entity.getType())) {
5470 ArrayLength = CAT->getSize().getZExtValue();
5471 ResultType = Entity.getType();
5472 } else if (const VariableArrayType *VAT =
5473 S.getASTContext().getAsVariableArrayType(Entity.getType())) {
5474 // Braced-initialization of variable array types is not allowed, even if
5475 // the size is greater than or equal to the number of args, so we don't
5476 // allow them to be initialized via parenthesized aggregate initialization
5477 // either.
5478 const Expr *SE = VAT->getSizeExpr();
5479 S.Diag(SE->getBeginLoc(), diag::err_variable_object_no_init)
5480 << SE->getSourceRange();
5481 return;
5482 } else {
5483 assert(isa<IncompleteArrayType>(Entity.getType()));
5484 ArrayLength = Args.size();
5485 }
5486 EntityIndexToProcess = ArrayLength;
5487
5488 // ...the ith array element is copy-initialized with xi for each
5489 // 1 <= i <= k
5490 for (Expr *E : Args) {
5491 InitializedEntity SubEntity = InitializedEntity::InitializeElement(
5492 S.getASTContext(), EntityIndexToProcess, Entity);
5493 InitializationKind SubKind = InitializationKind::CreateForInit(
5494 E->getExprLoc(), /*isDirectInit=*/false, E);
5495 if (!HandleInitializedEntity(SubEntity, SubKind, E))
5496 return;
5497 }
5498 // ...and value-initialized for each k < i <= n;
5499 if (ArrayLength > Args.size() || Entity.isVariableLengthArrayNew()) {
5500 InitializedEntity SubEntity = InitializedEntity::InitializeElement(
5501 S.getASTContext(), Args.size(), Entity);
5502 InitializationKind SubKind = InitializationKind::CreateValue(
5503 Kind.getLocation(), Kind.getLocation(), Kind.getLocation(), true);
5504 if (!HandleInitializedEntity(SubEntity, SubKind, nullptr, &ArrayFiller))
5505 return;
5506 }
5507
5508 if (ResultType.isNull()) {
5509 ResultType = S.Context.getConstantArrayType(
5510 AT->getElementType(), llvm::APInt(/*numBits=*/32, ArrayLength),
5511 /*SizeExpr=*/nullptr, ArraySizeModifier::Normal, 0);
5512 }
5513 } else if (auto *RT = Entity.getType()->getAs<RecordType>()) {
5514 bool IsUnion = RT->isUnionType();
5515 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
5516 if (RD->isInvalidDecl()) {
5517 // Exit early to avoid confusion when processing members.
5518 // We do the same for braced list initialization in
5519 // `CheckStructUnionTypes`.
5520 Sequence.SetFailed(
5521 clang::InitializationSequence::FK_ParenthesizedListInitFailed);
5522 return;
5523 }
5524
5525 if (!IsUnion) {
5526 for (const CXXBaseSpecifier &Base : RD->bases()) {
5527 InitializedEntity SubEntity = InitializedEntity::InitializeBase(
5528 S.getASTContext(), &Base, false, &Entity);
5529 if (EntityIndexToProcess < Args.size()) {
5530 // C++ [dcl.init]p16.6.2.2.
5531 // ...the object is initialized is follows. Let e1, ..., en be the
5532 // elements of the aggregate([dcl.init.aggr]). Let x1, ..., xk be
5533 // the elements of the expression-list...The element ei is
5534 // copy-initialized with xi for 1 <= i <= k.
5535 Expr *E = Args[EntityIndexToProcess];
5536 InitializationKind SubKind = InitializationKind::CreateForInit(
5537 E->getExprLoc(), /*isDirectInit=*/false, E);
5538 if (!HandleInitializedEntity(SubEntity, SubKind, E))
5539 return;
5540 } else {
5541 // We've processed all of the args, but there are still base classes
5542 // that have to be initialized.
5543 // C++ [dcl.init]p17.6.2.2
5544 // The remaining elements...otherwise are value initialzed
5545 InitializationKind SubKind = InitializationKind::CreateValue(
5546 Kind.getLocation(), Kind.getLocation(), Kind.getLocation(),
5547 /*IsImplicit=*/true);
5548 if (!HandleInitializedEntity(SubEntity, SubKind, nullptr))
5549 return;
5550 }
5551 EntityIndexToProcess++;
5552 }
5553 }
5554
5555 for (FieldDecl *FD : RD->fields()) {
5556 // Unnamed bitfields should not be initialized at all, either with an arg
5557 // or by default.
5558 if (FD->isUnnamedBitfield())
5559 continue;
5560
5561 InitializedEntity SubEntity =
5562 InitializedEntity::InitializeMemberFromParenAggInit(FD);
5563
5564 if (EntityIndexToProcess < Args.size()) {
5565 // ...The element ei is copy-initialized with xi for 1 <= i <= k.
5566 Expr *E = Args[EntityIndexToProcess];
5567
5568 // Incomplete array types indicate flexible array members. Do not allow
5569 // paren list initializations of structs with these members, as GCC
5570 // doesn't either.
5571 if (FD->getType()->isIncompleteArrayType()) {
5572 if (!VerifyOnly) {
5573 S.Diag(E->getBeginLoc(), diag::err_flexible_array_init)
5574 << SourceRange(E->getBeginLoc(), E->getEndLoc());
5575 S.Diag(FD->getLocation(), diag::note_flexible_array_member) << FD;
5576 }
5577 Sequence.SetFailed(
5578 InitializationSequence::FK_ParenthesizedListInitFailed);
5579 return;
5580 }
5581
5582 InitializationKind SubKind = InitializationKind::CreateForInit(
5583 E->getExprLoc(), /*isDirectInit=*/false, E);
5584 if (!HandleInitializedEntity(SubEntity, SubKind, E))
5585 return;
5586
5587 // Unions should have only one initializer expression, so we bail out
5588 // after processing the first field. If there are more initializers then
5589 // it will be caught when we later check whether EntityIndexToProcess is
5590 // less than Args.size();
5591 if (IsUnion) {
5592 InitializedFieldInUnion = FD;
5593 EntityIndexToProcess = 1;
5594 break;
5595 }
5596 } else {
5597 // We've processed all of the args, but there are still members that
5598 // have to be initialized.
5599 if (FD->hasInClassInitializer()) {
5600 if (!VerifyOnly) {
5601 // C++ [dcl.init]p16.6.2.2
5602 // The remaining elements are initialized with their default
5603 // member initializers, if any
5604 ExprResult DIE = S.BuildCXXDefaultInitExpr(
5605 Kind.getParenOrBraceRange().getEnd(), FD);
5606 if (DIE.isInvalid())
5607 return;
5608 S.checkInitializerLifetime(SubEntity, DIE.get());
5609 InitExprs.push_back(DIE.get());
5610 }
5611 } else {
5612 // C++ [dcl.init]p17.6.2.2
5613 // The remaining elements...otherwise are value initialzed
5614 if (FD->getType()->isReferenceType()) {
5615 Sequence.SetFailed(
5616 InitializationSequence::FK_ParenthesizedListInitFailed);
5617 if (!VerifyOnly) {
5618 SourceRange SR = Kind.getParenOrBraceRange();
5619 S.Diag(SR.getEnd(), diag::err_init_reference_member_uninitialized)
5620 << FD->getType() << SR;
5621 S.Diag(FD->getLocation(), diag::note_uninit_reference_member);
5622 }
5623 return;
5624 }
5625 InitializationKind SubKind = InitializationKind::CreateValue(
5626 Kind.getLocation(), Kind.getLocation(), Kind.getLocation(), true);
5627 if (!HandleInitializedEntity(SubEntity, SubKind, nullptr))
5628 return;
5629 }
5630 }
5631 EntityIndexToProcess++;
5632 }
5633 ResultType = Entity.getType();
5634 }
5635
5636 // Not all of the args have been processed, so there must've been more args
5637 // than were required to initialize the element.
5638 if (EntityIndexToProcess < Args.size()) {
5639 Sequence.SetFailed(InitializationSequence::FK_ParenthesizedListInitFailed);
5640 if (!VerifyOnly) {
5641 QualType T = Entity.getType();
5642 int InitKind = T->isArrayType() ? 0 : T->isUnionType() ? 3 : 4;
5643 SourceRange ExcessInitSR(Args[EntityIndexToProcess]->getBeginLoc(),
5644 Args.back()->getEndLoc());
5645 S.Diag(Kind.getLocation(), diag::err_excess_initializers)
5646 << InitKind << ExcessInitSR;
5647 }
5648 return;
5649 }
5650
5651 if (VerifyOnly) {
5652 Sequence.setSequenceKind(InitializationSequence::NormalSequence);
5653 Sequence.AddParenthesizedListInitStep(Entity.getType());
5654 } else if (Result) {
5655 SourceRange SR = Kind.getParenOrBraceRange();
5656 auto *CPLIE = CXXParenListInitExpr::Create(
5657 S.getASTContext(), InitExprs, ResultType, Args.size(),
5658 Kind.getLocation(), SR.getBegin(), SR.getEnd());
5659 if (ArrayFiller)
5660 CPLIE->setArrayFiller(ArrayFiller);
5661 if (InitializedFieldInUnion)
5662 CPLIE->setInitializedFieldInUnion(InitializedFieldInUnion);
5663 *Result = CPLIE;
5664 S.Diag(Kind.getLocation(),
5665 diag::warn_cxx17_compat_aggregate_init_paren_list)
5666 << Kind.getLocation() << SR << ResultType;
5667 }
5668 }
5669
5670 /// Attempt a user-defined conversion between two types (C++ [dcl.init]),
5671 /// which enumerates all conversion functions and performs overload resolution
5672 /// to select the best.
TryUserDefinedConversion(Sema & S,QualType DestType,const InitializationKind & Kind,Expr * Initializer,InitializationSequence & Sequence,bool TopLevelOfInitList)5673 static void TryUserDefinedConversion(Sema &S,
5674 QualType DestType,
5675 const InitializationKind &Kind,
5676 Expr *Initializer,
5677 InitializationSequence &Sequence,
5678 bool TopLevelOfInitList) {
5679 assert(!DestType->isReferenceType() && "References are handled elsewhere");
5680 QualType SourceType = Initializer->getType();
5681 assert((DestType->isRecordType() || SourceType->isRecordType()) &&
5682 "Must have a class type to perform a user-defined conversion");
5683
5684 // Build the candidate set directly in the initialization sequence
5685 // structure, so that it will persist if we fail.
5686 OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
5687 CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
5688 CandidateSet.setDestAS(DestType.getQualifiers().getAddressSpace());
5689
5690 // Determine whether we are allowed to call explicit constructors or
5691 // explicit conversion operators.
5692 bool AllowExplicit = Kind.AllowExplicit();
5693
5694 if (const RecordType *DestRecordType = DestType->getAs<RecordType>()) {
5695 // The type we're converting to is a class type. Enumerate its constructors
5696 // to see if there is a suitable conversion.
5697 CXXRecordDecl *DestRecordDecl
5698 = cast<CXXRecordDecl>(DestRecordType->getDecl());
5699
5700 // Try to complete the type we're converting to.
5701 if (S.isCompleteType(Kind.getLocation(), DestType)) {
5702 for (NamedDecl *D : S.LookupConstructors(DestRecordDecl)) {
5703 auto Info = getConstructorInfo(D);
5704 if (!Info.Constructor)
5705 continue;
5706
5707 if (!Info.Constructor->isInvalidDecl() &&
5708 Info.Constructor->isConvertingConstructor(/*AllowExplicit*/true)) {
5709 if (Info.ConstructorTmpl)
5710 S.AddTemplateOverloadCandidate(
5711 Info.ConstructorTmpl, Info.FoundDecl,
5712 /*ExplicitArgs*/ nullptr, Initializer, CandidateSet,
5713 /*SuppressUserConversions=*/true,
5714 /*PartialOverloading*/ false, AllowExplicit);
5715 else
5716 S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl,
5717 Initializer, CandidateSet,
5718 /*SuppressUserConversions=*/true,
5719 /*PartialOverloading*/ false, AllowExplicit);
5720 }
5721 }
5722 }
5723 }
5724
5725 SourceLocation DeclLoc = Initializer->getBeginLoc();
5726
5727 if (const RecordType *SourceRecordType = SourceType->getAs<RecordType>()) {
5728 // The type we're converting from is a class type, enumerate its conversion
5729 // functions.
5730
5731 // We can only enumerate the conversion functions for a complete type; if
5732 // the type isn't complete, simply skip this step.
5733 if (S.isCompleteType(DeclLoc, SourceType)) {
5734 CXXRecordDecl *SourceRecordDecl
5735 = cast<CXXRecordDecl>(SourceRecordType->getDecl());
5736
5737 const auto &Conversions =
5738 SourceRecordDecl->getVisibleConversionFunctions();
5739 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
5740 NamedDecl *D = *I;
5741 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
5742 if (isa<UsingShadowDecl>(D))
5743 D = cast<UsingShadowDecl>(D)->getTargetDecl();
5744
5745 FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
5746 CXXConversionDecl *Conv;
5747 if (ConvTemplate)
5748 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
5749 else
5750 Conv = cast<CXXConversionDecl>(D);
5751
5752 if (ConvTemplate)
5753 S.AddTemplateConversionCandidate(
5754 ConvTemplate, I.getPair(), ActingDC, Initializer, DestType,
5755 CandidateSet, AllowExplicit, AllowExplicit);
5756 else
5757 S.AddConversionCandidate(Conv, I.getPair(), ActingDC, Initializer,
5758 DestType, CandidateSet, AllowExplicit,
5759 AllowExplicit);
5760 }
5761 }
5762 }
5763
5764 // Perform overload resolution. If it fails, return the failed result.
5765 OverloadCandidateSet::iterator Best;
5766 if (OverloadingResult Result
5767 = CandidateSet.BestViableFunction(S, DeclLoc, Best)) {
5768 Sequence.SetOverloadFailure(
5769 InitializationSequence::FK_UserConversionOverloadFailed, Result);
5770
5771 // [class.copy.elision]p3:
5772 // In some copy-initialization contexts, a two-stage overload resolution
5773 // is performed.
5774 // If the first overload resolution selects a deleted function, we also
5775 // need the initialization sequence to decide whether to perform the second
5776 // overload resolution.
5777 if (!(Result == OR_Deleted &&
5778 Kind.getKind() == InitializationKind::IK_Copy))
5779 return;
5780 }
5781
5782 FunctionDecl *Function = Best->Function;
5783 Function->setReferenced();
5784 bool HadMultipleCandidates = (CandidateSet.size() > 1);
5785
5786 if (isa<CXXConstructorDecl>(Function)) {
5787 // Add the user-defined conversion step. Any cv-qualification conversion is
5788 // subsumed by the initialization. Per DR5, the created temporary is of the
5789 // cv-unqualified type of the destination.
5790 Sequence.AddUserConversionStep(Function, Best->FoundDecl,
5791 DestType.getUnqualifiedType(),
5792 HadMultipleCandidates);
5793
5794 // C++14 and before:
5795 // - if the function is a constructor, the call initializes a temporary
5796 // of the cv-unqualified version of the destination type. The [...]
5797 // temporary [...] is then used to direct-initialize, according to the
5798 // rules above, the object that is the destination of the
5799 // copy-initialization.
5800 // Note that this just performs a simple object copy from the temporary.
5801 //
5802 // C++17:
5803 // - if the function is a constructor, the call is a prvalue of the
5804 // cv-unqualified version of the destination type whose return object
5805 // is initialized by the constructor. The call is used to
5806 // direct-initialize, according to the rules above, the object that
5807 // is the destination of the copy-initialization.
5808 // Therefore we need to do nothing further.
5809 //
5810 // FIXME: Mark this copy as extraneous.
5811 if (!S.getLangOpts().CPlusPlus17)
5812 Sequence.AddFinalCopy(DestType);
5813 else if (DestType.hasQualifiers())
5814 Sequence.AddQualificationConversionStep(DestType, VK_PRValue);
5815 return;
5816 }
5817
5818 // Add the user-defined conversion step that calls the conversion function.
5819 QualType ConvType = Function->getCallResultType();
5820 Sequence.AddUserConversionStep(Function, Best->FoundDecl, ConvType,
5821 HadMultipleCandidates);
5822
5823 if (ConvType->getAs<RecordType>()) {
5824 // The call is used to direct-initialize [...] the object that is the
5825 // destination of the copy-initialization.
5826 //
5827 // In C++17, this does not call a constructor if we enter /17.6.1:
5828 // - If the initializer expression is a prvalue and the cv-unqualified
5829 // version of the source type is the same as the class of the
5830 // destination [... do not make an extra copy]
5831 //
5832 // FIXME: Mark this copy as extraneous.
5833 if (!S.getLangOpts().CPlusPlus17 ||
5834 Function->getReturnType()->isReferenceType() ||
5835 !S.Context.hasSameUnqualifiedType(ConvType, DestType))
5836 Sequence.AddFinalCopy(DestType);
5837 else if (!S.Context.hasSameType(ConvType, DestType))
5838 Sequence.AddQualificationConversionStep(DestType, VK_PRValue);
5839 return;
5840 }
5841
5842 // If the conversion following the call to the conversion function
5843 // is interesting, add it as a separate step.
5844 if (Best->FinalConversion.First || Best->FinalConversion.Second ||
5845 Best->FinalConversion.Third) {
5846 ImplicitConversionSequence ICS;
5847 ICS.setStandard();
5848 ICS.Standard = Best->FinalConversion;
5849 Sequence.AddConversionSequenceStep(ICS, DestType, TopLevelOfInitList);
5850 }
5851 }
5852
5853 /// An egregious hack for compatibility with libstdc++-4.2: in <tr1/hashtable>,
5854 /// a function with a pointer return type contains a 'return false;' statement.
5855 /// In C++11, 'false' is not a null pointer, so this breaks the build of any
5856 /// code using that header.
5857 ///
5858 /// Work around this by treating 'return false;' as zero-initializing the result
5859 /// if it's used in a pointer-returning function in a system header.
isLibstdcxxPointerReturnFalseHack(Sema & S,const InitializedEntity & Entity,const Expr * Init)5860 static bool isLibstdcxxPointerReturnFalseHack(Sema &S,
5861 const InitializedEntity &Entity,
5862 const Expr *Init) {
5863 return S.getLangOpts().CPlusPlus11 &&
5864 Entity.getKind() == InitializedEntity::EK_Result &&
5865 Entity.getType()->isPointerType() &&
5866 isa<CXXBoolLiteralExpr>(Init) &&
5867 !cast<CXXBoolLiteralExpr>(Init)->getValue() &&
5868 S.getSourceManager().isInSystemHeader(Init->getExprLoc());
5869 }
5870
5871 /// The non-zero enum values here are indexes into diagnostic alternatives.
5872 enum InvalidICRKind { IIK_okay, IIK_nonlocal, IIK_nonscalar };
5873
5874 /// Determines whether this expression is an acceptable ICR source.
isInvalidICRSource(ASTContext & C,Expr * e,bool isAddressOf,bool & isWeakAccess)5875 static InvalidICRKind isInvalidICRSource(ASTContext &C, Expr *e,
5876 bool isAddressOf, bool &isWeakAccess) {
5877 // Skip parens.
5878 e = e->IgnoreParens();
5879
5880 // Skip address-of nodes.
5881 if (UnaryOperator *op = dyn_cast<UnaryOperator>(e)) {
5882 if (op->getOpcode() == UO_AddrOf)
5883 return isInvalidICRSource(C, op->getSubExpr(), /*addressof*/ true,
5884 isWeakAccess);
5885
5886 // Skip certain casts.
5887 } else if (CastExpr *ce = dyn_cast<CastExpr>(e)) {
5888 switch (ce->getCastKind()) {
5889 case CK_Dependent:
5890 case CK_BitCast:
5891 case CK_LValueBitCast:
5892 case CK_NoOp:
5893 return isInvalidICRSource(C, ce->getSubExpr(), isAddressOf, isWeakAccess);
5894
5895 case CK_ArrayToPointerDecay:
5896 return IIK_nonscalar;
5897
5898 case CK_NullToPointer:
5899 return IIK_okay;
5900
5901 default:
5902 break;
5903 }
5904
5905 // If we have a declaration reference, it had better be a local variable.
5906 } else if (isa<DeclRefExpr>(e)) {
5907 // set isWeakAccess to true, to mean that there will be an implicit
5908 // load which requires a cleanup.
5909 if (e->getType().getObjCLifetime() == Qualifiers::OCL_Weak)
5910 isWeakAccess = true;
5911
5912 if (!isAddressOf) return IIK_nonlocal;
5913
5914 VarDecl *var = dyn_cast<VarDecl>(cast<DeclRefExpr>(e)->getDecl());
5915 if (!var) return IIK_nonlocal;
5916
5917 return (var->hasLocalStorage() ? IIK_okay : IIK_nonlocal);
5918
5919 // If we have a conditional operator, check both sides.
5920 } else if (ConditionalOperator *cond = dyn_cast<ConditionalOperator>(e)) {
5921 if (InvalidICRKind iik = isInvalidICRSource(C, cond->getLHS(), isAddressOf,
5922 isWeakAccess))
5923 return iik;
5924
5925 return isInvalidICRSource(C, cond->getRHS(), isAddressOf, isWeakAccess);
5926
5927 // These are never scalar.
5928 } else if (isa<ArraySubscriptExpr>(e)) {
5929 return IIK_nonscalar;
5930
5931 // Otherwise, it needs to be a null pointer constant.
5932 } else {
5933 return (e->isNullPointerConstant(C, Expr::NPC_ValueDependentIsNull)
5934 ? IIK_okay : IIK_nonlocal);
5935 }
5936
5937 return IIK_nonlocal;
5938 }
5939
5940 /// Check whether the given expression is a valid operand for an
5941 /// indirect copy/restore.
checkIndirectCopyRestoreSource(Sema & S,Expr * src)5942 static void checkIndirectCopyRestoreSource(Sema &S, Expr *src) {
5943 assert(src->isPRValue());
5944 bool isWeakAccess = false;
5945 InvalidICRKind iik = isInvalidICRSource(S.Context, src, false, isWeakAccess);
5946 // If isWeakAccess to true, there will be an implicit
5947 // load which requires a cleanup.
5948 if (S.getLangOpts().ObjCAutoRefCount && isWeakAccess)
5949 S.Cleanup.setExprNeedsCleanups(true);
5950
5951 if (iik == IIK_okay) return;
5952
5953 S.Diag(src->getExprLoc(), diag::err_arc_nonlocal_writeback)
5954 << ((unsigned) iik - 1) // shift index into diagnostic explanations
5955 << src->getSourceRange();
5956 }
5957
5958 /// Determine whether we have compatible array types for the
5959 /// purposes of GNU by-copy array initialization.
hasCompatibleArrayTypes(ASTContext & Context,const ArrayType * Dest,const ArrayType * Source)5960 static bool hasCompatibleArrayTypes(ASTContext &Context, const ArrayType *Dest,
5961 const ArrayType *Source) {
5962 // If the source and destination array types are equivalent, we're
5963 // done.
5964 if (Context.hasSameType(QualType(Dest, 0), QualType(Source, 0)))
5965 return true;
5966
5967 // Make sure that the element types are the same.
5968 if (!Context.hasSameType(Dest->getElementType(), Source->getElementType()))
5969 return false;
5970
5971 // The only mismatch we allow is when the destination is an
5972 // incomplete array type and the source is a constant array type.
5973 return Source->isConstantArrayType() && Dest->isIncompleteArrayType();
5974 }
5975
tryObjCWritebackConversion(Sema & S,InitializationSequence & Sequence,const InitializedEntity & Entity,Expr * Initializer)5976 static bool tryObjCWritebackConversion(Sema &S,
5977 InitializationSequence &Sequence,
5978 const InitializedEntity &Entity,
5979 Expr *Initializer) {
5980 bool ArrayDecay = false;
5981 QualType ArgType = Initializer->getType();
5982 QualType ArgPointee;
5983 if (const ArrayType *ArgArrayType = S.Context.getAsArrayType(ArgType)) {
5984 ArrayDecay = true;
5985 ArgPointee = ArgArrayType->getElementType();
5986 ArgType = S.Context.getPointerType(ArgPointee);
5987 }
5988
5989 // Handle write-back conversion.
5990 QualType ConvertedArgType;
5991 if (!S.isObjCWritebackConversion(ArgType, Entity.getType(),
5992 ConvertedArgType))
5993 return false;
5994
5995 // We should copy unless we're passing to an argument explicitly
5996 // marked 'out'.
5997 bool ShouldCopy = true;
5998 if (ParmVarDecl *param = cast_or_null<ParmVarDecl>(Entity.getDecl()))
5999 ShouldCopy = (param->getObjCDeclQualifier() != ParmVarDecl::OBJC_TQ_Out);
6000
6001 // Do we need an lvalue conversion?
6002 if (ArrayDecay || Initializer->isGLValue()) {
6003 ImplicitConversionSequence ICS;
6004 ICS.setStandard();
6005 ICS.Standard.setAsIdentityConversion();
6006
6007 QualType ResultType;
6008 if (ArrayDecay) {
6009 ICS.Standard.First = ICK_Array_To_Pointer;
6010 ResultType = S.Context.getPointerType(ArgPointee);
6011 } else {
6012 ICS.Standard.First = ICK_Lvalue_To_Rvalue;
6013 ResultType = Initializer->getType().getNonLValueExprType(S.Context);
6014 }
6015
6016 Sequence.AddConversionSequenceStep(ICS, ResultType);
6017 }
6018
6019 Sequence.AddPassByIndirectCopyRestoreStep(Entity.getType(), ShouldCopy);
6020 return true;
6021 }
6022
TryOCLSamplerInitialization(Sema & S,InitializationSequence & Sequence,QualType DestType,Expr * Initializer)6023 static bool TryOCLSamplerInitialization(Sema &S,
6024 InitializationSequence &Sequence,
6025 QualType DestType,
6026 Expr *Initializer) {
6027 if (!S.getLangOpts().OpenCL || !DestType->isSamplerT() ||
6028 (!Initializer->isIntegerConstantExpr(S.Context) &&
6029 !Initializer->getType()->isSamplerT()))
6030 return false;
6031
6032 Sequence.AddOCLSamplerInitStep(DestType);
6033 return true;
6034 }
6035
IsZeroInitializer(Expr * Initializer,Sema & S)6036 static bool IsZeroInitializer(Expr *Initializer, Sema &S) {
6037 return Initializer->isIntegerConstantExpr(S.getASTContext()) &&
6038 (Initializer->EvaluateKnownConstInt(S.getASTContext()) == 0);
6039 }
6040
TryOCLZeroOpaqueTypeInitialization(Sema & S,InitializationSequence & Sequence,QualType DestType,Expr * Initializer)6041 static bool TryOCLZeroOpaqueTypeInitialization(Sema &S,
6042 InitializationSequence &Sequence,
6043 QualType DestType,
6044 Expr *Initializer) {
6045 if (!S.getLangOpts().OpenCL)
6046 return false;
6047
6048 //
6049 // OpenCL 1.2 spec, s6.12.10
6050 //
6051 // The event argument can also be used to associate the
6052 // async_work_group_copy with a previous async copy allowing
6053 // an event to be shared by multiple async copies; otherwise
6054 // event should be zero.
6055 //
6056 if (DestType->isEventT() || DestType->isQueueT()) {
6057 if (!IsZeroInitializer(Initializer, S))
6058 return false;
6059
6060 Sequence.AddOCLZeroOpaqueTypeStep(DestType);
6061 return true;
6062 }
6063
6064 // We should allow zero initialization for all types defined in the
6065 // cl_intel_device_side_avc_motion_estimation extension, except
6066 // intel_sub_group_avc_mce_payload_t and intel_sub_group_avc_mce_result_t.
6067 if (S.getOpenCLOptions().isAvailableOption(
6068 "cl_intel_device_side_avc_motion_estimation", S.getLangOpts()) &&
6069 DestType->isOCLIntelSubgroupAVCType()) {
6070 if (DestType->isOCLIntelSubgroupAVCMcePayloadType() ||
6071 DestType->isOCLIntelSubgroupAVCMceResultType())
6072 return false;
6073 if (!IsZeroInitializer(Initializer, S))
6074 return false;
6075
6076 Sequence.AddOCLZeroOpaqueTypeStep(DestType);
6077 return true;
6078 }
6079
6080 return false;
6081 }
6082
InitializationSequence(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Args,bool TopLevelOfInitList,bool TreatUnavailableAsInvalid)6083 InitializationSequence::InitializationSequence(
6084 Sema &S, const InitializedEntity &Entity, const InitializationKind &Kind,
6085 MultiExprArg Args, bool TopLevelOfInitList, bool TreatUnavailableAsInvalid)
6086 : FailedOverloadResult(OR_Success),
6087 FailedCandidateSet(Kind.getLocation(), OverloadCandidateSet::CSK_Normal) {
6088 InitializeFrom(S, Entity, Kind, Args, TopLevelOfInitList,
6089 TreatUnavailableAsInvalid);
6090 }
6091
6092 /// Tries to get a FunctionDecl out of `E`. If it succeeds and we can take the
6093 /// address of that function, this returns true. Otherwise, it returns false.
isExprAnUnaddressableFunction(Sema & S,const Expr * E)6094 static bool isExprAnUnaddressableFunction(Sema &S, const Expr *E) {
6095 auto *DRE = dyn_cast<DeclRefExpr>(E);
6096 if (!DRE || !isa<FunctionDecl>(DRE->getDecl()))
6097 return false;
6098
6099 return !S.checkAddressOfFunctionIsAvailable(
6100 cast<FunctionDecl>(DRE->getDecl()));
6101 }
6102
6103 /// Determine whether we can perform an elementwise array copy for this kind
6104 /// of entity.
canPerformArrayCopy(const InitializedEntity & Entity)6105 static bool canPerformArrayCopy(const InitializedEntity &Entity) {
6106 switch (Entity.getKind()) {
6107 case InitializedEntity::EK_LambdaCapture:
6108 // C++ [expr.prim.lambda]p24:
6109 // For array members, the array elements are direct-initialized in
6110 // increasing subscript order.
6111 return true;
6112
6113 case InitializedEntity::EK_Variable:
6114 // C++ [dcl.decomp]p1:
6115 // [...] each element is copy-initialized or direct-initialized from the
6116 // corresponding element of the assignment-expression [...]
6117 return isa<DecompositionDecl>(Entity.getDecl());
6118
6119 case InitializedEntity::EK_Member:
6120 // C++ [class.copy.ctor]p14:
6121 // - if the member is an array, each element is direct-initialized with
6122 // the corresponding subobject of x
6123 return Entity.isImplicitMemberInitializer();
6124
6125 case InitializedEntity::EK_ArrayElement:
6126 // All the above cases are intended to apply recursively, even though none
6127 // of them actually say that.
6128 if (auto *E = Entity.getParent())
6129 return canPerformArrayCopy(*E);
6130 break;
6131
6132 default:
6133 break;
6134 }
6135
6136 return false;
6137 }
6138
InitializeFrom(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Args,bool TopLevelOfInitList,bool TreatUnavailableAsInvalid)6139 void InitializationSequence::InitializeFrom(Sema &S,
6140 const InitializedEntity &Entity,
6141 const InitializationKind &Kind,
6142 MultiExprArg Args,
6143 bool TopLevelOfInitList,
6144 bool TreatUnavailableAsInvalid) {
6145 ASTContext &Context = S.Context;
6146
6147 // Eliminate non-overload placeholder types in the arguments. We
6148 // need to do this before checking whether types are dependent
6149 // because lowering a pseudo-object expression might well give us
6150 // something of dependent type.
6151 for (unsigned I = 0, E = Args.size(); I != E; ++I)
6152 if (Args[I]->getType()->isNonOverloadPlaceholderType()) {
6153 // FIXME: should we be doing this here?
6154 ExprResult result = S.CheckPlaceholderExpr(Args[I]);
6155 if (result.isInvalid()) {
6156 SetFailed(FK_PlaceholderType);
6157 return;
6158 }
6159 Args[I] = result.get();
6160 }
6161
6162 // C++0x [dcl.init]p16:
6163 // The semantics of initializers are as follows. The destination type is
6164 // the type of the object or reference being initialized and the source
6165 // type is the type of the initializer expression. The source type is not
6166 // defined when the initializer is a braced-init-list or when it is a
6167 // parenthesized list of expressions.
6168 QualType DestType = Entity.getType();
6169
6170 if (DestType->isDependentType() ||
6171 Expr::hasAnyTypeDependentArguments(Args)) {
6172 SequenceKind = DependentSequence;
6173 return;
6174 }
6175
6176 // Almost everything is a normal sequence.
6177 setSequenceKind(NormalSequence);
6178
6179 QualType SourceType;
6180 Expr *Initializer = nullptr;
6181 if (Args.size() == 1) {
6182 Initializer = Args[0];
6183 if (S.getLangOpts().ObjC) {
6184 if (S.CheckObjCBridgeRelatedConversions(Initializer->getBeginLoc(),
6185 DestType, Initializer->getType(),
6186 Initializer) ||
6187 S.CheckConversionToObjCLiteral(DestType, Initializer))
6188 Args[0] = Initializer;
6189 }
6190 if (!isa<InitListExpr>(Initializer))
6191 SourceType = Initializer->getType();
6192 }
6193
6194 // - If the initializer is a (non-parenthesized) braced-init-list, the
6195 // object is list-initialized (8.5.4).
6196 if (Kind.getKind() != InitializationKind::IK_Direct) {
6197 if (InitListExpr *InitList = dyn_cast_or_null<InitListExpr>(Initializer)) {
6198 TryListInitialization(S, Entity, Kind, InitList, *this,
6199 TreatUnavailableAsInvalid);
6200 return;
6201 }
6202 }
6203
6204 // - If the destination type is a reference type, see 8.5.3.
6205 if (DestType->isReferenceType()) {
6206 // C++0x [dcl.init.ref]p1:
6207 // A variable declared to be a T& or T&&, that is, "reference to type T"
6208 // (8.3.2), shall be initialized by an object, or function, of type T or
6209 // by an object that can be converted into a T.
6210 // (Therefore, multiple arguments are not permitted.)
6211 if (Args.size() != 1)
6212 SetFailed(FK_TooManyInitsForReference);
6213 // C++17 [dcl.init.ref]p5:
6214 // A reference [...] is initialized by an expression [...] as follows:
6215 // If the initializer is not an expression, presumably we should reject,
6216 // but the standard fails to actually say so.
6217 else if (isa<InitListExpr>(Args[0]))
6218 SetFailed(FK_ParenthesizedListInitForReference);
6219 else
6220 TryReferenceInitialization(S, Entity, Kind, Args[0], *this,
6221 TopLevelOfInitList);
6222 return;
6223 }
6224
6225 // - If the initializer is (), the object is value-initialized.
6226 if (Kind.getKind() == InitializationKind::IK_Value ||
6227 (Kind.getKind() == InitializationKind::IK_Direct && Args.empty())) {
6228 TryValueInitialization(S, Entity, Kind, *this);
6229 return;
6230 }
6231
6232 // Handle default initialization.
6233 if (Kind.getKind() == InitializationKind::IK_Default) {
6234 TryDefaultInitialization(S, Entity, Kind, *this);
6235 return;
6236 }
6237
6238 // - If the destination type is an array of characters, an array of
6239 // char16_t, an array of char32_t, or an array of wchar_t, and the
6240 // initializer is a string literal, see 8.5.2.
6241 // - Otherwise, if the destination type is an array, the program is
6242 // ill-formed.
6243 if (const ArrayType *DestAT = Context.getAsArrayType(DestType)) {
6244 if (Initializer && isa<VariableArrayType>(DestAT)) {
6245 SetFailed(FK_VariableLengthArrayHasInitializer);
6246 return;
6247 }
6248
6249 if (Initializer) {
6250 switch (IsStringInit(Initializer, DestAT, Context)) {
6251 case SIF_None:
6252 TryStringLiteralInitialization(S, Entity, Kind, Initializer, *this);
6253 return;
6254 case SIF_NarrowStringIntoWideChar:
6255 SetFailed(FK_NarrowStringIntoWideCharArray);
6256 return;
6257 case SIF_WideStringIntoChar:
6258 SetFailed(FK_WideStringIntoCharArray);
6259 return;
6260 case SIF_IncompatWideStringIntoWideChar:
6261 SetFailed(FK_IncompatWideStringIntoWideChar);
6262 return;
6263 case SIF_PlainStringIntoUTF8Char:
6264 SetFailed(FK_PlainStringIntoUTF8Char);
6265 return;
6266 case SIF_UTF8StringIntoPlainChar:
6267 SetFailed(FK_UTF8StringIntoPlainChar);
6268 return;
6269 case SIF_Other:
6270 break;
6271 }
6272 }
6273
6274 // Some kinds of initialization permit an array to be initialized from
6275 // another array of the same type, and perform elementwise initialization.
6276 if (Initializer && isa<ConstantArrayType>(DestAT) &&
6277 S.Context.hasSameUnqualifiedType(Initializer->getType(),
6278 Entity.getType()) &&
6279 canPerformArrayCopy(Entity)) {
6280 // If source is a prvalue, use it directly.
6281 if (Initializer->isPRValue()) {
6282 AddArrayInitStep(DestType, /*IsGNUExtension*/false);
6283 return;
6284 }
6285
6286 // Emit element-at-a-time copy loop.
6287 InitializedEntity Element =
6288 InitializedEntity::InitializeElement(S.Context, 0, Entity);
6289 QualType InitEltT =
6290 Context.getAsArrayType(Initializer->getType())->getElementType();
6291 OpaqueValueExpr OVE(Initializer->getExprLoc(), InitEltT,
6292 Initializer->getValueKind(),
6293 Initializer->getObjectKind());
6294 Expr *OVEAsExpr = &OVE;
6295 InitializeFrom(S, Element, Kind, OVEAsExpr, TopLevelOfInitList,
6296 TreatUnavailableAsInvalid);
6297 if (!Failed())
6298 AddArrayInitLoopStep(Entity.getType(), InitEltT);
6299 return;
6300 }
6301
6302 // Note: as an GNU C extension, we allow initialization of an
6303 // array from a compound literal that creates an array of the same
6304 // type, so long as the initializer has no side effects.
6305 if (!S.getLangOpts().CPlusPlus && Initializer &&
6306 isa<CompoundLiteralExpr>(Initializer->IgnoreParens()) &&
6307 Initializer->getType()->isArrayType()) {
6308 const ArrayType *SourceAT
6309 = Context.getAsArrayType(Initializer->getType());
6310 if (!hasCompatibleArrayTypes(S.Context, DestAT, SourceAT))
6311 SetFailed(FK_ArrayTypeMismatch);
6312 else if (Initializer->HasSideEffects(S.Context))
6313 SetFailed(FK_NonConstantArrayInit);
6314 else {
6315 AddArrayInitStep(DestType, /*IsGNUExtension*/true);
6316 }
6317 }
6318 // Note: as a GNU C++ extension, we allow list-initialization of a
6319 // class member of array type from a parenthesized initializer list.
6320 else if (S.getLangOpts().CPlusPlus &&
6321 Entity.getKind() == InitializedEntity::EK_Member &&
6322 Initializer && isa<InitListExpr>(Initializer)) {
6323 TryListInitialization(S, Entity, Kind, cast<InitListExpr>(Initializer),
6324 *this, TreatUnavailableAsInvalid);
6325 AddParenthesizedArrayInitStep(DestType);
6326 } else if (S.getLangOpts().CPlusPlus20 && !TopLevelOfInitList &&
6327 Kind.getKind() == InitializationKind::IK_Direct)
6328 TryOrBuildParenListInitialization(S, Entity, Kind, Args, *this,
6329 /*VerifyOnly=*/true);
6330 else if (DestAT->getElementType()->isCharType())
6331 SetFailed(FK_ArrayNeedsInitListOrStringLiteral);
6332 else if (IsWideCharCompatible(DestAT->getElementType(), Context))
6333 SetFailed(FK_ArrayNeedsInitListOrWideStringLiteral);
6334 else
6335 SetFailed(FK_ArrayNeedsInitList);
6336
6337 return;
6338 }
6339
6340 // Determine whether we should consider writeback conversions for
6341 // Objective-C ARC.
6342 bool allowObjCWritebackConversion = S.getLangOpts().ObjCAutoRefCount &&
6343 Entity.isParameterKind();
6344
6345 if (TryOCLSamplerInitialization(S, *this, DestType, Initializer))
6346 return;
6347
6348 // We're at the end of the line for C: it's either a write-back conversion
6349 // or it's a C assignment. There's no need to check anything else.
6350 if (!S.getLangOpts().CPlusPlus) {
6351 assert(Initializer && "Initializer must be non-null");
6352 // If allowed, check whether this is an Objective-C writeback conversion.
6353 if (allowObjCWritebackConversion &&
6354 tryObjCWritebackConversion(S, *this, Entity, Initializer)) {
6355 return;
6356 }
6357
6358 if (TryOCLZeroOpaqueTypeInitialization(S, *this, DestType, Initializer))
6359 return;
6360
6361 // Handle initialization in C
6362 AddCAssignmentStep(DestType);
6363 MaybeProduceObjCObject(S, *this, Entity);
6364 return;
6365 }
6366
6367 assert(S.getLangOpts().CPlusPlus);
6368
6369 // - If the destination type is a (possibly cv-qualified) class type:
6370 if (DestType->isRecordType()) {
6371 // - If the initialization is direct-initialization, or if it is
6372 // copy-initialization where the cv-unqualified version of the
6373 // source type is the same class as, or a derived class of, the
6374 // class of the destination, constructors are considered. [...]
6375 if (Kind.getKind() == InitializationKind::IK_Direct ||
6376 (Kind.getKind() == InitializationKind::IK_Copy &&
6377 (Context.hasSameUnqualifiedType(SourceType, DestType) ||
6378 (Initializer && S.IsDerivedFrom(Initializer->getBeginLoc(),
6379 SourceType, DestType))))) {
6380 TryConstructorInitialization(S, Entity, Kind, Args, DestType, DestType,
6381 *this);
6382
6383 // We fall back to the "no matching constructor" path if the
6384 // failed candidate set has functions other than the three default
6385 // constructors. For example, conversion function.
6386 if (const auto *RD =
6387 dyn_cast<CXXRecordDecl>(DestType->getAs<RecordType>()->getDecl());
6388 // In general, we should call isCompleteType for RD to check its
6389 // completeness, we don't call it here as it was already called in the
6390 // above TryConstructorInitialization.
6391 S.getLangOpts().CPlusPlus20 && RD && RD->hasDefinition() &&
6392 RD->isAggregate() && Failed() &&
6393 getFailureKind() == FK_ConstructorOverloadFailed) {
6394 // Do not attempt paren list initialization if overload resolution
6395 // resolves to a deleted function .
6396 //
6397 // We may reach this condition if we have a union wrapping a class with
6398 // a non-trivial copy or move constructor and we call one of those two
6399 // constructors. The union is an aggregate, but the matched constructor
6400 // is implicitly deleted, so we need to prevent aggregate initialization
6401 // (otherwise, it'll attempt aggregate initialization by initializing
6402 // the first element with a reference to the union).
6403 OverloadCandidateSet::iterator Best;
6404 OverloadingResult OR = getFailedCandidateSet().BestViableFunction(
6405 S, Kind.getLocation(), Best);
6406 if (OR != OverloadingResult::OR_Deleted) {
6407 // C++20 [dcl.init] 17.6.2.2:
6408 // - Otherwise, if no constructor is viable, the destination type is
6409 // an
6410 // aggregate class, and the initializer is a parenthesized
6411 // expression-list.
6412 TryOrBuildParenListInitialization(S, Entity, Kind, Args, *this,
6413 /*VerifyOnly=*/true);
6414 }
6415 }
6416 } else {
6417 // - Otherwise (i.e., for the remaining copy-initialization cases),
6418 // user-defined conversion sequences that can convert from the
6419 // source type to the destination type or (when a conversion
6420 // function is used) to a derived class thereof are enumerated as
6421 // described in 13.3.1.4, and the best one is chosen through
6422 // overload resolution (13.3).
6423 assert(Initializer && "Initializer must be non-null");
6424 TryUserDefinedConversion(S, DestType, Kind, Initializer, *this,
6425 TopLevelOfInitList);
6426 }
6427 return;
6428 }
6429
6430 assert(Args.size() >= 1 && "Zero-argument case handled above");
6431
6432 // For HLSL ext vector types we allow list initialization behavior for C++
6433 // constructor syntax. This is accomplished by converting initialization
6434 // arguments an InitListExpr late.
6435 if (S.getLangOpts().HLSL && DestType->isExtVectorType() &&
6436 (SourceType.isNull() ||
6437 !Context.hasSameUnqualifiedType(SourceType, DestType))) {
6438
6439 llvm::SmallVector<Expr *> InitArgs;
6440 for (auto *Arg : Args) {
6441 if (Arg->getType()->isExtVectorType()) {
6442 const auto *VTy = Arg->getType()->castAs<ExtVectorType>();
6443 unsigned Elm = VTy->getNumElements();
6444 for (unsigned Idx = 0; Idx < Elm; ++Idx) {
6445 InitArgs.emplace_back(new (Context) ArraySubscriptExpr(
6446 Arg,
6447 IntegerLiteral::Create(
6448 Context, llvm::APInt(Context.getIntWidth(Context.IntTy), Idx),
6449 Context.IntTy, SourceLocation()),
6450 VTy->getElementType(), Arg->getValueKind(), Arg->getObjectKind(),
6451 SourceLocation()));
6452 }
6453 } else
6454 InitArgs.emplace_back(Arg);
6455 }
6456 InitListExpr *ILE = new (Context) InitListExpr(
6457 S.getASTContext(), SourceLocation(), InitArgs, SourceLocation());
6458 Args[0] = ILE;
6459 AddListInitializationStep(DestType);
6460 return;
6461 }
6462
6463 // The remaining cases all need a source type.
6464 if (Args.size() > 1) {
6465 SetFailed(FK_TooManyInitsForScalar);
6466 return;
6467 } else if (isa<InitListExpr>(Args[0])) {
6468 SetFailed(FK_ParenthesizedListInitForScalar);
6469 return;
6470 }
6471
6472 // - Otherwise, if the source type is a (possibly cv-qualified) class
6473 // type, conversion functions are considered.
6474 if (!SourceType.isNull() && SourceType->isRecordType()) {
6475 assert(Initializer && "Initializer must be non-null");
6476 // For a conversion to _Atomic(T) from either T or a class type derived
6477 // from T, initialize the T object then convert to _Atomic type.
6478 bool NeedAtomicConversion = false;
6479 if (const AtomicType *Atomic = DestType->getAs<AtomicType>()) {
6480 if (Context.hasSameUnqualifiedType(SourceType, Atomic->getValueType()) ||
6481 S.IsDerivedFrom(Initializer->getBeginLoc(), SourceType,
6482 Atomic->getValueType())) {
6483 DestType = Atomic->getValueType();
6484 NeedAtomicConversion = true;
6485 }
6486 }
6487
6488 TryUserDefinedConversion(S, DestType, Kind, Initializer, *this,
6489 TopLevelOfInitList);
6490 MaybeProduceObjCObject(S, *this, Entity);
6491 if (!Failed() && NeedAtomicConversion)
6492 AddAtomicConversionStep(Entity.getType());
6493 return;
6494 }
6495
6496 // - Otherwise, if the initialization is direct-initialization, the source
6497 // type is std::nullptr_t, and the destination type is bool, the initial
6498 // value of the object being initialized is false.
6499 if (!SourceType.isNull() && SourceType->isNullPtrType() &&
6500 DestType->isBooleanType() &&
6501 Kind.getKind() == InitializationKind::IK_Direct) {
6502 AddConversionSequenceStep(
6503 ImplicitConversionSequence::getNullptrToBool(SourceType, DestType,
6504 Initializer->isGLValue()),
6505 DestType);
6506 return;
6507 }
6508
6509 // - Otherwise, the initial value of the object being initialized is the
6510 // (possibly converted) value of the initializer expression. Standard
6511 // conversions (Clause 4) will be used, if necessary, to convert the
6512 // initializer expression to the cv-unqualified version of the
6513 // destination type; no user-defined conversions are considered.
6514
6515 ImplicitConversionSequence ICS
6516 = S.TryImplicitConversion(Initializer, DestType,
6517 /*SuppressUserConversions*/true,
6518 Sema::AllowedExplicit::None,
6519 /*InOverloadResolution*/ false,
6520 /*CStyle=*/Kind.isCStyleOrFunctionalCast(),
6521 allowObjCWritebackConversion);
6522
6523 if (ICS.isStandard() &&
6524 ICS.Standard.Second == ICK_Writeback_Conversion) {
6525 // Objective-C ARC writeback conversion.
6526
6527 // We should copy unless we're passing to an argument explicitly
6528 // marked 'out'.
6529 bool ShouldCopy = true;
6530 if (ParmVarDecl *Param = cast_or_null<ParmVarDecl>(Entity.getDecl()))
6531 ShouldCopy = (Param->getObjCDeclQualifier() != ParmVarDecl::OBJC_TQ_Out);
6532
6533 // If there was an lvalue adjustment, add it as a separate conversion.
6534 if (ICS.Standard.First == ICK_Array_To_Pointer ||
6535 ICS.Standard.First == ICK_Lvalue_To_Rvalue) {
6536 ImplicitConversionSequence LvalueICS;
6537 LvalueICS.setStandard();
6538 LvalueICS.Standard.setAsIdentityConversion();
6539 LvalueICS.Standard.setAllToTypes(ICS.Standard.getToType(0));
6540 LvalueICS.Standard.First = ICS.Standard.First;
6541 AddConversionSequenceStep(LvalueICS, ICS.Standard.getToType(0));
6542 }
6543
6544 AddPassByIndirectCopyRestoreStep(DestType, ShouldCopy);
6545 } else if (ICS.isBad()) {
6546 DeclAccessPair dap;
6547 if (isLibstdcxxPointerReturnFalseHack(S, Entity, Initializer)) {
6548 AddZeroInitializationStep(Entity.getType());
6549 } else if (Initializer->getType() == Context.OverloadTy &&
6550 !S.ResolveAddressOfOverloadedFunction(Initializer, DestType,
6551 false, dap))
6552 SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
6553 else if (Initializer->getType()->isFunctionType() &&
6554 isExprAnUnaddressableFunction(S, Initializer))
6555 SetFailed(InitializationSequence::FK_AddressOfUnaddressableFunction);
6556 else
6557 SetFailed(InitializationSequence::FK_ConversionFailed);
6558 } else {
6559 AddConversionSequenceStep(ICS, DestType, TopLevelOfInitList);
6560
6561 MaybeProduceObjCObject(S, *this, Entity);
6562 }
6563 }
6564
~InitializationSequence()6565 InitializationSequence::~InitializationSequence() {
6566 for (auto &S : Steps)
6567 S.Destroy();
6568 }
6569
6570 //===----------------------------------------------------------------------===//
6571 // Perform initialization
6572 //===----------------------------------------------------------------------===//
6573 static Sema::AssignmentAction
getAssignmentAction(const InitializedEntity & Entity,bool Diagnose=false)6574 getAssignmentAction(const InitializedEntity &Entity, bool Diagnose = false) {
6575 switch(Entity.getKind()) {
6576 case InitializedEntity::EK_Variable:
6577 case InitializedEntity::EK_New:
6578 case InitializedEntity::EK_Exception:
6579 case InitializedEntity::EK_Base:
6580 case InitializedEntity::EK_Delegating:
6581 return Sema::AA_Initializing;
6582
6583 case InitializedEntity::EK_Parameter:
6584 if (Entity.getDecl() &&
6585 isa<ObjCMethodDecl>(Entity.getDecl()->getDeclContext()))
6586 return Sema::AA_Sending;
6587
6588 return Sema::AA_Passing;
6589
6590 case InitializedEntity::EK_Parameter_CF_Audited:
6591 if (Entity.getDecl() &&
6592 isa<ObjCMethodDecl>(Entity.getDecl()->getDeclContext()))
6593 return Sema::AA_Sending;
6594
6595 return !Diagnose ? Sema::AA_Passing : Sema::AA_Passing_CFAudited;
6596
6597 case InitializedEntity::EK_Result:
6598 case InitializedEntity::EK_StmtExprResult: // FIXME: Not quite right.
6599 return Sema::AA_Returning;
6600
6601 case InitializedEntity::EK_Temporary:
6602 case InitializedEntity::EK_RelatedResult:
6603 // FIXME: Can we tell apart casting vs. converting?
6604 return Sema::AA_Casting;
6605
6606 case InitializedEntity::EK_TemplateParameter:
6607 // This is really initialization, but refer to it as conversion for
6608 // consistency with CheckConvertedConstantExpression.
6609 return Sema::AA_Converting;
6610
6611 case InitializedEntity::EK_Member:
6612 case InitializedEntity::EK_ParenAggInitMember:
6613 case InitializedEntity::EK_Binding:
6614 case InitializedEntity::EK_ArrayElement:
6615 case InitializedEntity::EK_VectorElement:
6616 case InitializedEntity::EK_ComplexElement:
6617 case InitializedEntity::EK_BlockElement:
6618 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6619 case InitializedEntity::EK_LambdaCapture:
6620 case InitializedEntity::EK_CompoundLiteralInit:
6621 return Sema::AA_Initializing;
6622 }
6623
6624 llvm_unreachable("Invalid EntityKind!");
6625 }
6626
6627 /// Whether we should bind a created object as a temporary when
6628 /// initializing the given entity.
shouldBindAsTemporary(const InitializedEntity & Entity)6629 static bool shouldBindAsTemporary(const InitializedEntity &Entity) {
6630 switch (Entity.getKind()) {
6631 case InitializedEntity::EK_ArrayElement:
6632 case InitializedEntity::EK_Member:
6633 case InitializedEntity::EK_ParenAggInitMember:
6634 case InitializedEntity::EK_Result:
6635 case InitializedEntity::EK_StmtExprResult:
6636 case InitializedEntity::EK_New:
6637 case InitializedEntity::EK_Variable:
6638 case InitializedEntity::EK_Base:
6639 case InitializedEntity::EK_Delegating:
6640 case InitializedEntity::EK_VectorElement:
6641 case InitializedEntity::EK_ComplexElement:
6642 case InitializedEntity::EK_Exception:
6643 case InitializedEntity::EK_BlockElement:
6644 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6645 case InitializedEntity::EK_LambdaCapture:
6646 case InitializedEntity::EK_CompoundLiteralInit:
6647 case InitializedEntity::EK_TemplateParameter:
6648 return false;
6649
6650 case InitializedEntity::EK_Parameter:
6651 case InitializedEntity::EK_Parameter_CF_Audited:
6652 case InitializedEntity::EK_Temporary:
6653 case InitializedEntity::EK_RelatedResult:
6654 case InitializedEntity::EK_Binding:
6655 return true;
6656 }
6657
6658 llvm_unreachable("missed an InitializedEntity kind?");
6659 }
6660
6661 /// Whether the given entity, when initialized with an object
6662 /// created for that initialization, requires destruction.
shouldDestroyEntity(const InitializedEntity & Entity)6663 static bool shouldDestroyEntity(const InitializedEntity &Entity) {
6664 switch (Entity.getKind()) {
6665 case InitializedEntity::EK_Result:
6666 case InitializedEntity::EK_StmtExprResult:
6667 case InitializedEntity::EK_New:
6668 case InitializedEntity::EK_Base:
6669 case InitializedEntity::EK_Delegating:
6670 case InitializedEntity::EK_VectorElement:
6671 case InitializedEntity::EK_ComplexElement:
6672 case InitializedEntity::EK_BlockElement:
6673 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6674 case InitializedEntity::EK_LambdaCapture:
6675 return false;
6676
6677 case InitializedEntity::EK_Member:
6678 case InitializedEntity::EK_ParenAggInitMember:
6679 case InitializedEntity::EK_Binding:
6680 case InitializedEntity::EK_Variable:
6681 case InitializedEntity::EK_Parameter:
6682 case InitializedEntity::EK_Parameter_CF_Audited:
6683 case InitializedEntity::EK_TemplateParameter:
6684 case InitializedEntity::EK_Temporary:
6685 case InitializedEntity::EK_ArrayElement:
6686 case InitializedEntity::EK_Exception:
6687 case InitializedEntity::EK_CompoundLiteralInit:
6688 case InitializedEntity::EK_RelatedResult:
6689 return true;
6690 }
6691
6692 llvm_unreachable("missed an InitializedEntity kind?");
6693 }
6694
6695 /// Get the location at which initialization diagnostics should appear.
getInitializationLoc(const InitializedEntity & Entity,Expr * Initializer)6696 static SourceLocation getInitializationLoc(const InitializedEntity &Entity,
6697 Expr *Initializer) {
6698 switch (Entity.getKind()) {
6699 case InitializedEntity::EK_Result:
6700 case InitializedEntity::EK_StmtExprResult:
6701 return Entity.getReturnLoc();
6702
6703 case InitializedEntity::EK_Exception:
6704 return Entity.getThrowLoc();
6705
6706 case InitializedEntity::EK_Variable:
6707 case InitializedEntity::EK_Binding:
6708 return Entity.getDecl()->getLocation();
6709
6710 case InitializedEntity::EK_LambdaCapture:
6711 return Entity.getCaptureLoc();
6712
6713 case InitializedEntity::EK_ArrayElement:
6714 case InitializedEntity::EK_Member:
6715 case InitializedEntity::EK_ParenAggInitMember:
6716 case InitializedEntity::EK_Parameter:
6717 case InitializedEntity::EK_Parameter_CF_Audited:
6718 case InitializedEntity::EK_TemplateParameter:
6719 case InitializedEntity::EK_Temporary:
6720 case InitializedEntity::EK_New:
6721 case InitializedEntity::EK_Base:
6722 case InitializedEntity::EK_Delegating:
6723 case InitializedEntity::EK_VectorElement:
6724 case InitializedEntity::EK_ComplexElement:
6725 case InitializedEntity::EK_BlockElement:
6726 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6727 case InitializedEntity::EK_CompoundLiteralInit:
6728 case InitializedEntity::EK_RelatedResult:
6729 return Initializer->getBeginLoc();
6730 }
6731 llvm_unreachable("missed an InitializedEntity kind?");
6732 }
6733
6734 /// Make a (potentially elidable) temporary copy of the object
6735 /// provided by the given initializer by calling the appropriate copy
6736 /// constructor.
6737 ///
6738 /// \param S The Sema object used for type-checking.
6739 ///
6740 /// \param T The type of the temporary object, which must either be
6741 /// the type of the initializer expression or a superclass thereof.
6742 ///
6743 /// \param Entity The entity being initialized.
6744 ///
6745 /// \param CurInit The initializer expression.
6746 ///
6747 /// \param IsExtraneousCopy Whether this is an "extraneous" copy that
6748 /// is permitted in C++03 (but not C++0x) when binding a reference to
6749 /// an rvalue.
6750 ///
6751 /// \returns An expression that copies the initializer expression into
6752 /// a temporary object, or an error expression if a copy could not be
6753 /// created.
CopyObject(Sema & S,QualType T,const InitializedEntity & Entity,ExprResult CurInit,bool IsExtraneousCopy)6754 static ExprResult CopyObject(Sema &S,
6755 QualType T,
6756 const InitializedEntity &Entity,
6757 ExprResult CurInit,
6758 bool IsExtraneousCopy) {
6759 if (CurInit.isInvalid())
6760 return CurInit;
6761 // Determine which class type we're copying to.
6762 Expr *CurInitExpr = (Expr *)CurInit.get();
6763 CXXRecordDecl *Class = nullptr;
6764 if (const RecordType *Record = T->getAs<RecordType>())
6765 Class = cast<CXXRecordDecl>(Record->getDecl());
6766 if (!Class)
6767 return CurInit;
6768
6769 SourceLocation Loc = getInitializationLoc(Entity, CurInit.get());
6770
6771 // Make sure that the type we are copying is complete.
6772 if (S.RequireCompleteType(Loc, T, diag::err_temp_copy_incomplete))
6773 return CurInit;
6774
6775 // Perform overload resolution using the class's constructors. Per
6776 // C++11 [dcl.init]p16, second bullet for class types, this initialization
6777 // is direct-initialization.
6778 OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
6779 DeclContext::lookup_result Ctors = S.LookupConstructors(Class);
6780
6781 OverloadCandidateSet::iterator Best;
6782 switch (ResolveConstructorOverload(
6783 S, Loc, CurInitExpr, CandidateSet, T, Ctors, Best,
6784 /*CopyInitializing=*/false, /*AllowExplicit=*/true,
6785 /*OnlyListConstructors=*/false, /*IsListInit=*/false,
6786 /*RequireActualConstructor=*/false,
6787 /*SecondStepOfCopyInit=*/true)) {
6788 case OR_Success:
6789 break;
6790
6791 case OR_No_Viable_Function:
6792 CandidateSet.NoteCandidates(
6793 PartialDiagnosticAt(
6794 Loc, S.PDiag(IsExtraneousCopy && !S.isSFINAEContext()
6795 ? diag::ext_rvalue_to_reference_temp_copy_no_viable
6796 : diag::err_temp_copy_no_viable)
6797 << (int)Entity.getKind() << CurInitExpr->getType()
6798 << CurInitExpr->getSourceRange()),
6799 S, OCD_AllCandidates, CurInitExpr);
6800 if (!IsExtraneousCopy || S.isSFINAEContext())
6801 return ExprError();
6802 return CurInit;
6803
6804 case OR_Ambiguous:
6805 CandidateSet.NoteCandidates(
6806 PartialDiagnosticAt(Loc, S.PDiag(diag::err_temp_copy_ambiguous)
6807 << (int)Entity.getKind()
6808 << CurInitExpr->getType()
6809 << CurInitExpr->getSourceRange()),
6810 S, OCD_AmbiguousCandidates, CurInitExpr);
6811 return ExprError();
6812
6813 case OR_Deleted:
6814 S.Diag(Loc, diag::err_temp_copy_deleted)
6815 << (int)Entity.getKind() << CurInitExpr->getType()
6816 << CurInitExpr->getSourceRange();
6817 S.NoteDeletedFunction(Best->Function);
6818 return ExprError();
6819 }
6820
6821 bool HadMultipleCandidates = CandidateSet.size() > 1;
6822
6823 CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Best->Function);
6824 SmallVector<Expr*, 8> ConstructorArgs;
6825 CurInit.get(); // Ownership transferred into MultiExprArg, below.
6826
6827 S.CheckConstructorAccess(Loc, Constructor, Best->FoundDecl, Entity,
6828 IsExtraneousCopy);
6829
6830 if (IsExtraneousCopy) {
6831 // If this is a totally extraneous copy for C++03 reference
6832 // binding purposes, just return the original initialization
6833 // expression. We don't generate an (elided) copy operation here
6834 // because doing so would require us to pass down a flag to avoid
6835 // infinite recursion, where each step adds another extraneous,
6836 // elidable copy.
6837
6838 // Instantiate the default arguments of any extra parameters in
6839 // the selected copy constructor, as if we were going to create a
6840 // proper call to the copy constructor.
6841 for (unsigned I = 1, N = Constructor->getNumParams(); I != N; ++I) {
6842 ParmVarDecl *Parm = Constructor->getParamDecl(I);
6843 if (S.RequireCompleteType(Loc, Parm->getType(),
6844 diag::err_call_incomplete_argument))
6845 break;
6846
6847 // Build the default argument expression; we don't actually care
6848 // if this succeeds or not, because this routine will complain
6849 // if there was a problem.
6850 S.BuildCXXDefaultArgExpr(Loc, Constructor, Parm);
6851 }
6852
6853 return CurInitExpr;
6854 }
6855
6856 // Determine the arguments required to actually perform the
6857 // constructor call (we might have derived-to-base conversions, or
6858 // the copy constructor may have default arguments).
6859 if (S.CompleteConstructorCall(Constructor, T, CurInitExpr, Loc,
6860 ConstructorArgs))
6861 return ExprError();
6862
6863 // C++0x [class.copy]p32:
6864 // When certain criteria are met, an implementation is allowed to
6865 // omit the copy/move construction of a class object, even if the
6866 // copy/move constructor and/or destructor for the object have
6867 // side effects. [...]
6868 // - when a temporary class object that has not been bound to a
6869 // reference (12.2) would be copied/moved to a class object
6870 // with the same cv-unqualified type, the copy/move operation
6871 // can be omitted by constructing the temporary object
6872 // directly into the target of the omitted copy/move
6873 //
6874 // Note that the other three bullets are handled elsewhere. Copy
6875 // elision for return statements and throw expressions are handled as part
6876 // of constructor initialization, while copy elision for exception handlers
6877 // is handled by the run-time.
6878 //
6879 // FIXME: If the function parameter is not the same type as the temporary, we
6880 // should still be able to elide the copy, but we don't have a way to
6881 // represent in the AST how much should be elided in this case.
6882 bool Elidable =
6883 CurInitExpr->isTemporaryObject(S.Context, Class) &&
6884 S.Context.hasSameUnqualifiedType(
6885 Best->Function->getParamDecl(0)->getType().getNonReferenceType(),
6886 CurInitExpr->getType());
6887
6888 // Actually perform the constructor call.
6889 CurInit = S.BuildCXXConstructExpr(
6890 Loc, T, Best->FoundDecl, Constructor, Elidable, ConstructorArgs,
6891 HadMultipleCandidates,
6892 /*ListInit*/ false,
6893 /*StdInitListInit*/ false,
6894 /*ZeroInit*/ false, CXXConstructionKind::Complete, SourceRange());
6895
6896 // If we're supposed to bind temporaries, do so.
6897 if (!CurInit.isInvalid() && shouldBindAsTemporary(Entity))
6898 CurInit = S.MaybeBindToTemporary(CurInit.getAs<Expr>());
6899 return CurInit;
6900 }
6901
6902 /// Check whether elidable copy construction for binding a reference to
6903 /// a temporary would have succeeded if we were building in C++98 mode, for
6904 /// -Wc++98-compat.
CheckCXX98CompatAccessibleCopy(Sema & S,const InitializedEntity & Entity,Expr * CurInitExpr)6905 static void CheckCXX98CompatAccessibleCopy(Sema &S,
6906 const InitializedEntity &Entity,
6907 Expr *CurInitExpr) {
6908 assert(S.getLangOpts().CPlusPlus11);
6909
6910 const RecordType *Record = CurInitExpr->getType()->getAs<RecordType>();
6911 if (!Record)
6912 return;
6913
6914 SourceLocation Loc = getInitializationLoc(Entity, CurInitExpr);
6915 if (S.Diags.isIgnored(diag::warn_cxx98_compat_temp_copy, Loc))
6916 return;
6917
6918 // Find constructors which would have been considered.
6919 OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
6920 DeclContext::lookup_result Ctors =
6921 S.LookupConstructors(cast<CXXRecordDecl>(Record->getDecl()));
6922
6923 // Perform overload resolution.
6924 OverloadCandidateSet::iterator Best;
6925 OverloadingResult OR = ResolveConstructorOverload(
6926 S, Loc, CurInitExpr, CandidateSet, CurInitExpr->getType(), Ctors, Best,
6927 /*CopyInitializing=*/false, /*AllowExplicit=*/true,
6928 /*OnlyListConstructors=*/false, /*IsListInit=*/false,
6929 /*RequireActualConstructor=*/false,
6930 /*SecondStepOfCopyInit=*/true);
6931
6932 PartialDiagnostic Diag = S.PDiag(diag::warn_cxx98_compat_temp_copy)
6933 << OR << (int)Entity.getKind() << CurInitExpr->getType()
6934 << CurInitExpr->getSourceRange();
6935
6936 switch (OR) {
6937 case OR_Success:
6938 S.CheckConstructorAccess(Loc, cast<CXXConstructorDecl>(Best->Function),
6939 Best->FoundDecl, Entity, Diag);
6940 // FIXME: Check default arguments as far as that's possible.
6941 break;
6942
6943 case OR_No_Viable_Function:
6944 CandidateSet.NoteCandidates(PartialDiagnosticAt(Loc, Diag), S,
6945 OCD_AllCandidates, CurInitExpr);
6946 break;
6947
6948 case OR_Ambiguous:
6949 CandidateSet.NoteCandidates(PartialDiagnosticAt(Loc, Diag), S,
6950 OCD_AmbiguousCandidates, CurInitExpr);
6951 break;
6952
6953 case OR_Deleted:
6954 S.Diag(Loc, Diag);
6955 S.NoteDeletedFunction(Best->Function);
6956 break;
6957 }
6958 }
6959
PrintInitLocationNote(Sema & S,const InitializedEntity & Entity)6960 void InitializationSequence::PrintInitLocationNote(Sema &S,
6961 const InitializedEntity &Entity) {
6962 if (Entity.isParamOrTemplateParamKind() && Entity.getDecl()) {
6963 if (Entity.getDecl()->getLocation().isInvalid())
6964 return;
6965
6966 if (Entity.getDecl()->getDeclName())
6967 S.Diag(Entity.getDecl()->getLocation(), diag::note_parameter_named_here)
6968 << Entity.getDecl()->getDeclName();
6969 else
6970 S.Diag(Entity.getDecl()->getLocation(), diag::note_parameter_here);
6971 }
6972 else if (Entity.getKind() == InitializedEntity::EK_RelatedResult &&
6973 Entity.getMethodDecl())
6974 S.Diag(Entity.getMethodDecl()->getLocation(),
6975 diag::note_method_return_type_change)
6976 << Entity.getMethodDecl()->getDeclName();
6977 }
6978
6979 /// Returns true if the parameters describe a constructor initialization of
6980 /// an explicit temporary object, e.g. "Point(x, y)".
isExplicitTemporary(const InitializedEntity & Entity,const InitializationKind & Kind,unsigned NumArgs)6981 static bool isExplicitTemporary(const InitializedEntity &Entity,
6982 const InitializationKind &Kind,
6983 unsigned NumArgs) {
6984 switch (Entity.getKind()) {
6985 case InitializedEntity::EK_Temporary:
6986 case InitializedEntity::EK_CompoundLiteralInit:
6987 case InitializedEntity::EK_RelatedResult:
6988 break;
6989 default:
6990 return false;
6991 }
6992
6993 switch (Kind.getKind()) {
6994 case InitializationKind::IK_DirectList:
6995 return true;
6996 // FIXME: Hack to work around cast weirdness.
6997 case InitializationKind::IK_Direct:
6998 case InitializationKind::IK_Value:
6999 return NumArgs != 1;
7000 default:
7001 return false;
7002 }
7003 }
7004
7005 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)7006 PerformConstructorInitialization(Sema &S,
7007 const InitializedEntity &Entity,
7008 const InitializationKind &Kind,
7009 MultiExprArg Args,
7010 const InitializationSequence::Step& Step,
7011 bool &ConstructorInitRequiresZeroInit,
7012 bool IsListInitialization,
7013 bool IsStdInitListInitialization,
7014 SourceLocation LBraceLoc,
7015 SourceLocation RBraceLoc) {
7016 unsigned NumArgs = Args.size();
7017 CXXConstructorDecl *Constructor
7018 = cast<CXXConstructorDecl>(Step.Function.Function);
7019 bool HadMultipleCandidates = Step.Function.HadMultipleCandidates;
7020
7021 // Build a call to the selected constructor.
7022 SmallVector<Expr*, 8> ConstructorArgs;
7023 SourceLocation Loc = (Kind.isCopyInit() && Kind.getEqualLoc().isValid())
7024 ? Kind.getEqualLoc()
7025 : Kind.getLocation();
7026
7027 if (Kind.getKind() == InitializationKind::IK_Default) {
7028 // Force even a trivial, implicit default constructor to be
7029 // semantically checked. We do this explicitly because we don't build
7030 // the definition for completely trivial constructors.
7031 assert(Constructor->getParent() && "No parent class for constructor.");
7032 if (Constructor->isDefaulted() && Constructor->isDefaultConstructor() &&
7033 Constructor->isTrivial() && !Constructor->isUsed(false)) {
7034 S.runWithSufficientStackSpace(Loc, [&] {
7035 S.DefineImplicitDefaultConstructor(Loc, Constructor);
7036 });
7037 }
7038 }
7039
7040 ExprResult CurInit((Expr *)nullptr);
7041
7042 // C++ [over.match.copy]p1:
7043 // - When initializing a temporary to be bound to the first parameter
7044 // of a constructor that takes a reference to possibly cv-qualified
7045 // T as its first argument, called with a single argument in the
7046 // context of direct-initialization, explicit conversion functions
7047 // are also considered.
7048 bool AllowExplicitConv =
7049 Kind.AllowExplicit() && !Kind.isCopyInit() && Args.size() == 1 &&
7050 hasCopyOrMoveCtorParam(S.Context,
7051 getConstructorInfo(Step.Function.FoundDecl));
7052
7053 // Determine the arguments required to actually perform the constructor
7054 // call.
7055 if (S.CompleteConstructorCall(Constructor, Step.Type, Args, Loc,
7056 ConstructorArgs, AllowExplicitConv,
7057 IsListInitialization))
7058 return ExprError();
7059
7060 if (isExplicitTemporary(Entity, Kind, NumArgs)) {
7061 // An explicitly-constructed temporary, e.g., X(1, 2).
7062 if (S.DiagnoseUseOfDecl(Step.Function.FoundDecl, Loc))
7063 return ExprError();
7064
7065 TypeSourceInfo *TSInfo = Entity.getTypeSourceInfo();
7066 if (!TSInfo)
7067 TSInfo = S.Context.getTrivialTypeSourceInfo(Entity.getType(), Loc);
7068 SourceRange ParenOrBraceRange =
7069 (Kind.getKind() == InitializationKind::IK_DirectList)
7070 ? SourceRange(LBraceLoc, RBraceLoc)
7071 : Kind.getParenOrBraceRange();
7072
7073 CXXConstructorDecl *CalleeDecl = Constructor;
7074 if (auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(
7075 Step.Function.FoundDecl.getDecl())) {
7076 CalleeDecl = S.findInheritingConstructor(Loc, Constructor, Shadow);
7077 }
7078 S.MarkFunctionReferenced(Loc, CalleeDecl);
7079
7080 CurInit = S.CheckForImmediateInvocation(
7081 CXXTemporaryObjectExpr::Create(
7082 S.Context, CalleeDecl,
7083 Entity.getType().getNonLValueExprType(S.Context), TSInfo,
7084 ConstructorArgs, ParenOrBraceRange, HadMultipleCandidates,
7085 IsListInitialization, IsStdInitListInitialization,
7086 ConstructorInitRequiresZeroInit),
7087 CalleeDecl);
7088 } else {
7089 CXXConstructionKind ConstructKind = CXXConstructionKind::Complete;
7090
7091 if (Entity.getKind() == InitializedEntity::EK_Base) {
7092 ConstructKind = Entity.getBaseSpecifier()->isVirtual()
7093 ? CXXConstructionKind::VirtualBase
7094 : CXXConstructionKind::NonVirtualBase;
7095 } else if (Entity.getKind() == InitializedEntity::EK_Delegating) {
7096 ConstructKind = CXXConstructionKind::Delegating;
7097 }
7098
7099 // Only get the parenthesis or brace range if it is a list initialization or
7100 // direct construction.
7101 SourceRange ParenOrBraceRange;
7102 if (IsListInitialization)
7103 ParenOrBraceRange = SourceRange(LBraceLoc, RBraceLoc);
7104 else if (Kind.getKind() == InitializationKind::IK_Direct)
7105 ParenOrBraceRange = Kind.getParenOrBraceRange();
7106
7107 // If the entity allows NRVO, mark the construction as elidable
7108 // unconditionally.
7109 if (Entity.allowsNRVO())
7110 CurInit = S.BuildCXXConstructExpr(Loc, Step.Type,
7111 Step.Function.FoundDecl,
7112 Constructor, /*Elidable=*/true,
7113 ConstructorArgs,
7114 HadMultipleCandidates,
7115 IsListInitialization,
7116 IsStdInitListInitialization,
7117 ConstructorInitRequiresZeroInit,
7118 ConstructKind,
7119 ParenOrBraceRange);
7120 else
7121 CurInit = S.BuildCXXConstructExpr(Loc, Step.Type,
7122 Step.Function.FoundDecl,
7123 Constructor,
7124 ConstructorArgs,
7125 HadMultipleCandidates,
7126 IsListInitialization,
7127 IsStdInitListInitialization,
7128 ConstructorInitRequiresZeroInit,
7129 ConstructKind,
7130 ParenOrBraceRange);
7131 }
7132 if (CurInit.isInvalid())
7133 return ExprError();
7134
7135 // Only check access if all of that succeeded.
7136 S.CheckConstructorAccess(Loc, Constructor, Step.Function.FoundDecl, Entity);
7137 if (S.DiagnoseUseOfDecl(Step.Function.FoundDecl, Loc))
7138 return ExprError();
7139
7140 if (const ArrayType *AT = S.Context.getAsArrayType(Entity.getType()))
7141 if (checkDestructorReference(S.Context.getBaseElementType(AT), Loc, S))
7142 return ExprError();
7143
7144 if (shouldBindAsTemporary(Entity))
7145 CurInit = S.MaybeBindToTemporary(CurInit.get());
7146
7147 return CurInit;
7148 }
7149
7150 namespace {
7151 enum LifetimeKind {
7152 /// The lifetime of a temporary bound to this entity ends at the end of the
7153 /// full-expression, and that's (probably) fine.
7154 LK_FullExpression,
7155
7156 /// The lifetime of a temporary bound to this entity is extended to the
7157 /// lifeitme of the entity itself.
7158 LK_Extended,
7159
7160 /// The lifetime of a temporary bound to this entity probably ends too soon,
7161 /// because the entity is allocated in a new-expression.
7162 LK_New,
7163
7164 /// The lifetime of a temporary bound to this entity ends too soon, because
7165 /// the entity is a return object.
7166 LK_Return,
7167
7168 /// The lifetime of a temporary bound to this entity ends too soon, because
7169 /// the entity is the result of a statement expression.
7170 LK_StmtExprResult,
7171
7172 /// This is a mem-initializer: if it would extend a temporary (other than via
7173 /// a default member initializer), the program is ill-formed.
7174 LK_MemInitializer,
7175 };
7176 using LifetimeResult =
7177 llvm::PointerIntPair<const InitializedEntity *, 3, LifetimeKind>;
7178 }
7179
7180 /// Determine the declaration which an initialized entity ultimately refers to,
7181 /// for the purpose of lifetime-extending a temporary bound to a reference in
7182 /// the initialization of \p Entity.
getEntityLifetime(const InitializedEntity * Entity,const InitializedEntity * InitField=nullptr)7183 static LifetimeResult getEntityLifetime(
7184 const InitializedEntity *Entity,
7185 const InitializedEntity *InitField = nullptr) {
7186 // C++11 [class.temporary]p5:
7187 switch (Entity->getKind()) {
7188 case InitializedEntity::EK_Variable:
7189 // The temporary [...] persists for the lifetime of the reference
7190 return {Entity, LK_Extended};
7191
7192 case InitializedEntity::EK_Member:
7193 // For subobjects, we look at the complete object.
7194 if (Entity->getParent())
7195 return getEntityLifetime(Entity->getParent(), Entity);
7196
7197 // except:
7198 // C++17 [class.base.init]p8:
7199 // A temporary expression bound to a reference member in a
7200 // mem-initializer is ill-formed.
7201 // C++17 [class.base.init]p11:
7202 // A temporary expression bound to a reference member from a
7203 // default member initializer is ill-formed.
7204 //
7205 // The context of p11 and its example suggest that it's only the use of a
7206 // default member initializer from a constructor that makes the program
7207 // ill-formed, not its mere existence, and that it can even be used by
7208 // aggregate initialization.
7209 return {Entity, Entity->isDefaultMemberInitializer() ? LK_Extended
7210 : LK_MemInitializer};
7211
7212 case InitializedEntity::EK_Binding:
7213 // Per [dcl.decomp]p3, the binding is treated as a variable of reference
7214 // type.
7215 return {Entity, LK_Extended};
7216
7217 case InitializedEntity::EK_Parameter:
7218 case InitializedEntity::EK_Parameter_CF_Audited:
7219 // -- A temporary bound to a reference parameter in a function call
7220 // persists until the completion of the full-expression containing
7221 // the call.
7222 return {nullptr, LK_FullExpression};
7223
7224 case InitializedEntity::EK_TemplateParameter:
7225 // FIXME: This will always be ill-formed; should we eagerly diagnose it here?
7226 return {nullptr, LK_FullExpression};
7227
7228 case InitializedEntity::EK_Result:
7229 // -- The lifetime of a temporary bound to the returned value in a
7230 // function return statement is not extended; the temporary is
7231 // destroyed at the end of the full-expression in the return statement.
7232 return {nullptr, LK_Return};
7233
7234 case InitializedEntity::EK_StmtExprResult:
7235 // FIXME: Should we lifetime-extend through the result of a statement
7236 // expression?
7237 return {nullptr, LK_StmtExprResult};
7238
7239 case InitializedEntity::EK_New:
7240 // -- A temporary bound to a reference in a new-initializer persists
7241 // until the completion of the full-expression containing the
7242 // new-initializer.
7243 return {nullptr, LK_New};
7244
7245 case InitializedEntity::EK_Temporary:
7246 case InitializedEntity::EK_CompoundLiteralInit:
7247 case InitializedEntity::EK_RelatedResult:
7248 // We don't yet know the storage duration of the surrounding temporary.
7249 // Assume it's got full-expression duration for now, it will patch up our
7250 // storage duration if that's not correct.
7251 return {nullptr, LK_FullExpression};
7252
7253 case InitializedEntity::EK_ArrayElement:
7254 // For subobjects, we look at the complete object.
7255 return getEntityLifetime(Entity->getParent(), InitField);
7256
7257 case InitializedEntity::EK_Base:
7258 // For subobjects, we look at the complete object.
7259 if (Entity->getParent())
7260 return getEntityLifetime(Entity->getParent(), InitField);
7261 return {InitField, LK_MemInitializer};
7262
7263 case InitializedEntity::EK_Delegating:
7264 // We can reach this case for aggregate initialization in a constructor:
7265 // struct A { int &&r; };
7266 // struct B : A { B() : A{0} {} };
7267 // In this case, use the outermost field decl as the context.
7268 return {InitField, LK_MemInitializer};
7269
7270 case InitializedEntity::EK_BlockElement:
7271 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
7272 case InitializedEntity::EK_LambdaCapture:
7273 case InitializedEntity::EK_VectorElement:
7274 case InitializedEntity::EK_ComplexElement:
7275 return {nullptr, LK_FullExpression};
7276
7277 case InitializedEntity::EK_Exception:
7278 // FIXME: Can we diagnose lifetime problems with exceptions?
7279 return {nullptr, LK_FullExpression};
7280
7281 case InitializedEntity::EK_ParenAggInitMember:
7282 // -- A temporary object bound to a reference element of an aggregate of
7283 // class type initialized from a parenthesized expression-list
7284 // [dcl.init, 9.3] persists until the completion of the full-expression
7285 // containing the expression-list.
7286 return {nullptr, LK_FullExpression};
7287 }
7288
7289 llvm_unreachable("unknown entity kind");
7290 }
7291
7292 namespace {
7293 enum ReferenceKind {
7294 /// Lifetime would be extended by a reference binding to a temporary.
7295 RK_ReferenceBinding,
7296 /// Lifetime would be extended by a std::initializer_list object binding to
7297 /// its backing array.
7298 RK_StdInitializerList,
7299 };
7300
7301 /// A temporary or local variable. This will be one of:
7302 /// * A MaterializeTemporaryExpr.
7303 /// * A DeclRefExpr whose declaration is a local.
7304 /// * An AddrLabelExpr.
7305 /// * A BlockExpr for a block with captures.
7306 using Local = Expr*;
7307
7308 /// Expressions we stepped over when looking for the local state. Any steps
7309 /// that would inhibit lifetime extension or take us out of subexpressions of
7310 /// the initializer are included.
7311 struct IndirectLocalPathEntry {
7312 enum EntryKind {
7313 DefaultInit,
7314 AddressOf,
7315 VarInit,
7316 LValToRVal,
7317 LifetimeBoundCall,
7318 TemporaryCopy,
7319 LambdaCaptureInit,
7320 GslReferenceInit,
7321 GslPointerInit
7322 } Kind;
7323 Expr *E;
7324 union {
7325 const Decl *D = nullptr;
7326 const LambdaCapture *Capture;
7327 };
IndirectLocalPathEntry__anonfc6101910911::IndirectLocalPathEntry7328 IndirectLocalPathEntry() {}
IndirectLocalPathEntry__anonfc6101910911::IndirectLocalPathEntry7329 IndirectLocalPathEntry(EntryKind K, Expr *E) : Kind(K), E(E) {}
IndirectLocalPathEntry__anonfc6101910911::IndirectLocalPathEntry7330 IndirectLocalPathEntry(EntryKind K, Expr *E, const Decl *D)
7331 : Kind(K), E(E), D(D) {}
IndirectLocalPathEntry__anonfc6101910911::IndirectLocalPathEntry7332 IndirectLocalPathEntry(EntryKind K, Expr *E, const LambdaCapture *Capture)
7333 : Kind(K), E(E), Capture(Capture) {}
7334 };
7335
7336 using IndirectLocalPath = llvm::SmallVectorImpl<IndirectLocalPathEntry>;
7337
7338 struct RevertToOldSizeRAII {
7339 IndirectLocalPath &Path;
7340 unsigned OldSize = Path.size();
RevertToOldSizeRAII__anonfc6101910911::RevertToOldSizeRAII7341 RevertToOldSizeRAII(IndirectLocalPath &Path) : Path(Path) {}
~RevertToOldSizeRAII__anonfc6101910911::RevertToOldSizeRAII7342 ~RevertToOldSizeRAII() { Path.resize(OldSize); }
7343 };
7344
7345 using LocalVisitor = llvm::function_ref<bool(IndirectLocalPath &Path, Local L,
7346 ReferenceKind RK)>;
7347 }
7348
isVarOnPath(IndirectLocalPath & Path,VarDecl * VD)7349 static bool isVarOnPath(IndirectLocalPath &Path, VarDecl *VD) {
7350 for (auto E : Path)
7351 if (E.Kind == IndirectLocalPathEntry::VarInit && E.D == VD)
7352 return true;
7353 return false;
7354 }
7355
pathContainsInit(IndirectLocalPath & Path)7356 static bool pathContainsInit(IndirectLocalPath &Path) {
7357 return llvm::any_of(Path, [=](IndirectLocalPathEntry E) {
7358 return E.Kind == IndirectLocalPathEntry::DefaultInit ||
7359 E.Kind == IndirectLocalPathEntry::VarInit;
7360 });
7361 }
7362
7363 static void visitLocalsRetainedByInitializer(IndirectLocalPath &Path,
7364 Expr *Init, LocalVisitor Visit,
7365 bool RevisitSubinits,
7366 bool EnableLifetimeWarnings);
7367
7368 static void visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
7369 Expr *Init, ReferenceKind RK,
7370 LocalVisitor Visit,
7371 bool EnableLifetimeWarnings);
7372
isRecordWithAttr(QualType Type)7373 template <typename T> static bool isRecordWithAttr(QualType Type) {
7374 if (auto *RD = Type->getAsCXXRecordDecl())
7375 return RD->hasAttr<T>();
7376 return false;
7377 }
7378
7379 // Decl::isInStdNamespace will return false for iterators in some STL
7380 // implementations due to them being defined in a namespace outside of the std
7381 // namespace.
isInStlNamespace(const Decl * D)7382 static bool isInStlNamespace(const Decl *D) {
7383 const DeclContext *DC = D->getDeclContext();
7384 if (!DC)
7385 return false;
7386 if (const auto *ND = dyn_cast<NamespaceDecl>(DC))
7387 if (const IdentifierInfo *II = ND->getIdentifier()) {
7388 StringRef Name = II->getName();
7389 if (Name.size() >= 2 && Name.front() == '_' &&
7390 (Name[1] == '_' || isUppercase(Name[1])))
7391 return true;
7392 }
7393
7394 return DC->isStdNamespace();
7395 }
7396
shouldTrackImplicitObjectArg(const CXXMethodDecl * Callee)7397 static bool shouldTrackImplicitObjectArg(const CXXMethodDecl *Callee) {
7398 if (auto *Conv = dyn_cast_or_null<CXXConversionDecl>(Callee))
7399 if (isRecordWithAttr<PointerAttr>(Conv->getConversionType()))
7400 return true;
7401 if (!isInStlNamespace(Callee->getParent()))
7402 return false;
7403 if (!isRecordWithAttr<PointerAttr>(
7404 Callee->getFunctionObjectParameterType()) &&
7405 !isRecordWithAttr<OwnerAttr>(Callee->getFunctionObjectParameterType()))
7406 return false;
7407 if (Callee->getReturnType()->isPointerType() ||
7408 isRecordWithAttr<PointerAttr>(Callee->getReturnType())) {
7409 if (!Callee->getIdentifier())
7410 return false;
7411 return llvm::StringSwitch<bool>(Callee->getName())
7412 .Cases("begin", "rbegin", "cbegin", "crbegin", true)
7413 .Cases("end", "rend", "cend", "crend", true)
7414 .Cases("c_str", "data", "get", true)
7415 // Map and set types.
7416 .Cases("find", "equal_range", "lower_bound", "upper_bound", true)
7417 .Default(false);
7418 } else if (Callee->getReturnType()->isReferenceType()) {
7419 if (!Callee->getIdentifier()) {
7420 auto OO = Callee->getOverloadedOperator();
7421 return OO == OverloadedOperatorKind::OO_Subscript ||
7422 OO == OverloadedOperatorKind::OO_Star;
7423 }
7424 return llvm::StringSwitch<bool>(Callee->getName())
7425 .Cases("front", "back", "at", "top", "value", true)
7426 .Default(false);
7427 }
7428 return false;
7429 }
7430
shouldTrackFirstArgument(const FunctionDecl * FD)7431 static bool shouldTrackFirstArgument(const FunctionDecl *FD) {
7432 if (!FD->getIdentifier() || FD->getNumParams() != 1)
7433 return false;
7434 const auto *RD = FD->getParamDecl(0)->getType()->getPointeeCXXRecordDecl();
7435 if (!FD->isInStdNamespace() || !RD || !RD->isInStdNamespace())
7436 return false;
7437 if (!isRecordWithAttr<PointerAttr>(QualType(RD->getTypeForDecl(), 0)) &&
7438 !isRecordWithAttr<OwnerAttr>(QualType(RD->getTypeForDecl(), 0)))
7439 return false;
7440 if (FD->getReturnType()->isPointerType() ||
7441 isRecordWithAttr<PointerAttr>(FD->getReturnType())) {
7442 return llvm::StringSwitch<bool>(FD->getName())
7443 .Cases("begin", "rbegin", "cbegin", "crbegin", true)
7444 .Cases("end", "rend", "cend", "crend", true)
7445 .Case("data", true)
7446 .Default(false);
7447 } else if (FD->getReturnType()->isReferenceType()) {
7448 return llvm::StringSwitch<bool>(FD->getName())
7449 .Cases("get", "any_cast", true)
7450 .Default(false);
7451 }
7452 return false;
7453 }
7454
handleGslAnnotatedTypes(IndirectLocalPath & Path,Expr * Call,LocalVisitor Visit)7455 static void handleGslAnnotatedTypes(IndirectLocalPath &Path, Expr *Call,
7456 LocalVisitor Visit) {
7457 auto VisitPointerArg = [&](const Decl *D, Expr *Arg, bool Value) {
7458 // We are not interested in the temporary base objects of gsl Pointers:
7459 // Temp().ptr; // Here ptr might not dangle.
7460 if (isa<MemberExpr>(Arg->IgnoreImpCasts()))
7461 return;
7462 // Once we initialized a value with a reference, it can no longer dangle.
7463 if (!Value) {
7464 for (const IndirectLocalPathEntry &PE : llvm::reverse(Path)) {
7465 if (PE.Kind == IndirectLocalPathEntry::GslReferenceInit)
7466 continue;
7467 if (PE.Kind == IndirectLocalPathEntry::GslPointerInit)
7468 return;
7469 break;
7470 }
7471 }
7472 Path.push_back({Value ? IndirectLocalPathEntry::GslPointerInit
7473 : IndirectLocalPathEntry::GslReferenceInit,
7474 Arg, D});
7475 if (Arg->isGLValue())
7476 visitLocalsRetainedByReferenceBinding(Path, Arg, RK_ReferenceBinding,
7477 Visit,
7478 /*EnableLifetimeWarnings=*/true);
7479 else
7480 visitLocalsRetainedByInitializer(Path, Arg, Visit, true,
7481 /*EnableLifetimeWarnings=*/true);
7482 Path.pop_back();
7483 };
7484
7485 if (auto *MCE = dyn_cast<CXXMemberCallExpr>(Call)) {
7486 const auto *MD = cast_or_null<CXXMethodDecl>(MCE->getDirectCallee());
7487 if (MD && shouldTrackImplicitObjectArg(MD))
7488 VisitPointerArg(MD, MCE->getImplicitObjectArgument(),
7489 !MD->getReturnType()->isReferenceType());
7490 return;
7491 } else if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(Call)) {
7492 FunctionDecl *Callee = OCE->getDirectCallee();
7493 if (Callee && Callee->isCXXInstanceMember() &&
7494 shouldTrackImplicitObjectArg(cast<CXXMethodDecl>(Callee)))
7495 VisitPointerArg(Callee, OCE->getArg(0),
7496 !Callee->getReturnType()->isReferenceType());
7497 return;
7498 } else if (auto *CE = dyn_cast<CallExpr>(Call)) {
7499 FunctionDecl *Callee = CE->getDirectCallee();
7500 if (Callee && shouldTrackFirstArgument(Callee))
7501 VisitPointerArg(Callee, CE->getArg(0),
7502 !Callee->getReturnType()->isReferenceType());
7503 return;
7504 }
7505
7506 if (auto *CCE = dyn_cast<CXXConstructExpr>(Call)) {
7507 const auto *Ctor = CCE->getConstructor();
7508 const CXXRecordDecl *RD = Ctor->getParent();
7509 if (CCE->getNumArgs() > 0 && RD->hasAttr<PointerAttr>())
7510 VisitPointerArg(Ctor->getParamDecl(0), CCE->getArgs()[0], true);
7511 }
7512 }
7513
implicitObjectParamIsLifetimeBound(const FunctionDecl * FD)7514 static bool implicitObjectParamIsLifetimeBound(const FunctionDecl *FD) {
7515 const TypeSourceInfo *TSI = FD->getTypeSourceInfo();
7516 if (!TSI)
7517 return false;
7518 // Don't declare this variable in the second operand of the for-statement;
7519 // GCC miscompiles that by ending its lifetime before evaluating the
7520 // third operand. See gcc.gnu.org/PR86769.
7521 AttributedTypeLoc ATL;
7522 for (TypeLoc TL = TSI->getTypeLoc();
7523 (ATL = TL.getAsAdjusted<AttributedTypeLoc>());
7524 TL = ATL.getModifiedLoc()) {
7525 if (ATL.getAttrAs<LifetimeBoundAttr>())
7526 return true;
7527 }
7528
7529 // Assume that all assignment operators with a "normal" return type return
7530 // *this, that is, an lvalue reference that is the same type as the implicit
7531 // object parameter (or the LHS for a non-member operator$=).
7532 OverloadedOperatorKind OO = FD->getDeclName().getCXXOverloadedOperator();
7533 if (OO == OO_Equal || isCompoundAssignmentOperator(OO)) {
7534 QualType RetT = FD->getReturnType();
7535 if (RetT->isLValueReferenceType()) {
7536 ASTContext &Ctx = FD->getASTContext();
7537 QualType LHST;
7538 auto *MD = dyn_cast<CXXMethodDecl>(FD);
7539 if (MD && MD->isCXXInstanceMember())
7540 LHST = Ctx.getLValueReferenceType(MD->getFunctionObjectParameterType());
7541 else
7542 LHST = MD->getParamDecl(0)->getType();
7543 if (Ctx.hasSameType(RetT, LHST))
7544 return true;
7545 }
7546 }
7547
7548 return false;
7549 }
7550
visitLifetimeBoundArguments(IndirectLocalPath & Path,Expr * Call,LocalVisitor Visit)7551 static void visitLifetimeBoundArguments(IndirectLocalPath &Path, Expr *Call,
7552 LocalVisitor Visit) {
7553 const FunctionDecl *Callee;
7554 ArrayRef<Expr*> Args;
7555
7556 if (auto *CE = dyn_cast<CallExpr>(Call)) {
7557 Callee = CE->getDirectCallee();
7558 Args = llvm::ArrayRef(CE->getArgs(), CE->getNumArgs());
7559 } else {
7560 auto *CCE = cast<CXXConstructExpr>(Call);
7561 Callee = CCE->getConstructor();
7562 Args = llvm::ArrayRef(CCE->getArgs(), CCE->getNumArgs());
7563 }
7564 if (!Callee)
7565 return;
7566
7567 Expr *ObjectArg = nullptr;
7568 if (isa<CXXOperatorCallExpr>(Call) && Callee->isCXXInstanceMember()) {
7569 ObjectArg = Args[0];
7570 Args = Args.slice(1);
7571 } else if (auto *MCE = dyn_cast<CXXMemberCallExpr>(Call)) {
7572 ObjectArg = MCE->getImplicitObjectArgument();
7573 }
7574
7575 auto VisitLifetimeBoundArg = [&](const Decl *D, Expr *Arg) {
7576 Path.push_back({IndirectLocalPathEntry::LifetimeBoundCall, Arg, D});
7577 if (Arg->isGLValue())
7578 visitLocalsRetainedByReferenceBinding(Path, Arg, RK_ReferenceBinding,
7579 Visit,
7580 /*EnableLifetimeWarnings=*/false);
7581 else
7582 visitLocalsRetainedByInitializer(Path, Arg, Visit, true,
7583 /*EnableLifetimeWarnings=*/false);
7584 Path.pop_back();
7585 };
7586
7587 bool CheckCoroCall = false;
7588 if (const auto *RD = Callee->getReturnType()->getAsRecordDecl()) {
7589 CheckCoroCall = RD->hasAttr<CoroLifetimeBoundAttr>() &&
7590 RD->hasAttr<CoroReturnTypeAttr>() &&
7591 !Callee->hasAttr<CoroDisableLifetimeBoundAttr>();
7592 }
7593
7594 if (ObjectArg) {
7595 bool CheckCoroObjArg = CheckCoroCall;
7596 // Coroutine lambda objects with empty capture list are not lifetimebound.
7597 if (auto *LE = dyn_cast<LambdaExpr>(ObjectArg->IgnoreImplicit());
7598 LE && LE->captures().empty())
7599 CheckCoroObjArg = false;
7600 // Allow `get_return_object()` as the object param (__promise) is not
7601 // lifetimebound.
7602 if (Sema::CanBeGetReturnObject(Callee))
7603 CheckCoroObjArg = false;
7604 if (implicitObjectParamIsLifetimeBound(Callee) || CheckCoroObjArg)
7605 VisitLifetimeBoundArg(Callee, ObjectArg);
7606 }
7607
7608 for (unsigned I = 0,
7609 N = std::min<unsigned>(Callee->getNumParams(), Args.size());
7610 I != N; ++I) {
7611 if (CheckCoroCall || Callee->getParamDecl(I)->hasAttr<LifetimeBoundAttr>())
7612 VisitLifetimeBoundArg(Callee->getParamDecl(I), Args[I]);
7613 }
7614 }
7615
7616 /// Visit the locals that would be reachable through a reference bound to the
7617 /// glvalue expression \c Init.
visitLocalsRetainedByReferenceBinding(IndirectLocalPath & Path,Expr * Init,ReferenceKind RK,LocalVisitor Visit,bool EnableLifetimeWarnings)7618 static void visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
7619 Expr *Init, ReferenceKind RK,
7620 LocalVisitor Visit,
7621 bool EnableLifetimeWarnings) {
7622 RevertToOldSizeRAII RAII(Path);
7623
7624 // Walk past any constructs which we can lifetime-extend across.
7625 Expr *Old;
7626 do {
7627 Old = Init;
7628
7629 if (auto *FE = dyn_cast<FullExpr>(Init))
7630 Init = FE->getSubExpr();
7631
7632 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
7633 // If this is just redundant braces around an initializer, step over it.
7634 if (ILE->isTransparent())
7635 Init = ILE->getInit(0);
7636 }
7637
7638 // Step over any subobject adjustments; we may have a materialized
7639 // temporary inside them.
7640 Init = const_cast<Expr *>(Init->skipRValueSubobjectAdjustments());
7641
7642 // Per current approach for DR1376, look through casts to reference type
7643 // when performing lifetime extension.
7644 if (CastExpr *CE = dyn_cast<CastExpr>(Init))
7645 if (CE->getSubExpr()->isGLValue())
7646 Init = CE->getSubExpr();
7647
7648 // Per the current approach for DR1299, look through array element access
7649 // on array glvalues when performing lifetime extension.
7650 if (auto *ASE = dyn_cast<ArraySubscriptExpr>(Init)) {
7651 Init = ASE->getBase();
7652 auto *ICE = dyn_cast<ImplicitCastExpr>(Init);
7653 if (ICE && ICE->getCastKind() == CK_ArrayToPointerDecay)
7654 Init = ICE->getSubExpr();
7655 else
7656 // We can't lifetime extend through this but we might still find some
7657 // retained temporaries.
7658 return visitLocalsRetainedByInitializer(Path, Init, Visit, true,
7659 EnableLifetimeWarnings);
7660 }
7661
7662 // Step into CXXDefaultInitExprs so we can diagnose cases where a
7663 // constructor inherits one as an implicit mem-initializer.
7664 if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Init)) {
7665 Path.push_back(
7666 {IndirectLocalPathEntry::DefaultInit, DIE, DIE->getField()});
7667 Init = DIE->getExpr();
7668 }
7669 } while (Init != Old);
7670
7671 if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(Init)) {
7672 if (Visit(Path, Local(MTE), RK))
7673 visitLocalsRetainedByInitializer(Path, MTE->getSubExpr(), Visit, true,
7674 EnableLifetimeWarnings);
7675 }
7676
7677 if (isa<CallExpr>(Init)) {
7678 if (EnableLifetimeWarnings)
7679 handleGslAnnotatedTypes(Path, Init, Visit);
7680 return visitLifetimeBoundArguments(Path, Init, Visit);
7681 }
7682
7683 switch (Init->getStmtClass()) {
7684 case Stmt::DeclRefExprClass: {
7685 // If we find the name of a local non-reference parameter, we could have a
7686 // lifetime problem.
7687 auto *DRE = cast<DeclRefExpr>(Init);
7688 auto *VD = dyn_cast<VarDecl>(DRE->getDecl());
7689 if (VD && VD->hasLocalStorage() &&
7690 !DRE->refersToEnclosingVariableOrCapture()) {
7691 if (!VD->getType()->isReferenceType()) {
7692 Visit(Path, Local(DRE), RK);
7693 } else if (isa<ParmVarDecl>(DRE->getDecl())) {
7694 // The lifetime of a reference parameter is unknown; assume it's OK
7695 // for now.
7696 break;
7697 } else if (VD->getInit() && !isVarOnPath(Path, VD)) {
7698 Path.push_back({IndirectLocalPathEntry::VarInit, DRE, VD});
7699 visitLocalsRetainedByReferenceBinding(Path, VD->getInit(),
7700 RK_ReferenceBinding, Visit,
7701 EnableLifetimeWarnings);
7702 }
7703 }
7704 break;
7705 }
7706
7707 case Stmt::UnaryOperatorClass: {
7708 // The only unary operator that make sense to handle here
7709 // is Deref. All others don't resolve to a "name." This includes
7710 // handling all sorts of rvalues passed to a unary operator.
7711 const UnaryOperator *U = cast<UnaryOperator>(Init);
7712 if (U->getOpcode() == UO_Deref)
7713 visitLocalsRetainedByInitializer(Path, U->getSubExpr(), Visit, true,
7714 EnableLifetimeWarnings);
7715 break;
7716 }
7717
7718 case Stmt::OMPArraySectionExprClass: {
7719 visitLocalsRetainedByInitializer(Path,
7720 cast<OMPArraySectionExpr>(Init)->getBase(),
7721 Visit, true, EnableLifetimeWarnings);
7722 break;
7723 }
7724
7725 case Stmt::ConditionalOperatorClass:
7726 case Stmt::BinaryConditionalOperatorClass: {
7727 auto *C = cast<AbstractConditionalOperator>(Init);
7728 if (!C->getTrueExpr()->getType()->isVoidType())
7729 visitLocalsRetainedByReferenceBinding(Path, C->getTrueExpr(), RK, Visit,
7730 EnableLifetimeWarnings);
7731 if (!C->getFalseExpr()->getType()->isVoidType())
7732 visitLocalsRetainedByReferenceBinding(Path, C->getFalseExpr(), RK, Visit,
7733 EnableLifetimeWarnings);
7734 break;
7735 }
7736
7737 // FIXME: Visit the left-hand side of an -> or ->*.
7738
7739 default:
7740 break;
7741 }
7742 }
7743
7744 /// Visit the locals that would be reachable through an object initialized by
7745 /// the prvalue expression \c Init.
visitLocalsRetainedByInitializer(IndirectLocalPath & Path,Expr * Init,LocalVisitor Visit,bool RevisitSubinits,bool EnableLifetimeWarnings)7746 static void visitLocalsRetainedByInitializer(IndirectLocalPath &Path,
7747 Expr *Init, LocalVisitor Visit,
7748 bool RevisitSubinits,
7749 bool EnableLifetimeWarnings) {
7750 RevertToOldSizeRAII RAII(Path);
7751
7752 Expr *Old;
7753 do {
7754 Old = Init;
7755
7756 // Step into CXXDefaultInitExprs so we can diagnose cases where a
7757 // constructor inherits one as an implicit mem-initializer.
7758 if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Init)) {
7759 Path.push_back({IndirectLocalPathEntry::DefaultInit, DIE, DIE->getField()});
7760 Init = DIE->getExpr();
7761 }
7762
7763 if (auto *FE = dyn_cast<FullExpr>(Init))
7764 Init = FE->getSubExpr();
7765
7766 // Dig out the expression which constructs the extended temporary.
7767 Init = const_cast<Expr *>(Init->skipRValueSubobjectAdjustments());
7768
7769 if (CXXBindTemporaryExpr *BTE = dyn_cast<CXXBindTemporaryExpr>(Init))
7770 Init = BTE->getSubExpr();
7771
7772 Init = Init->IgnoreParens();
7773
7774 // Step over value-preserving rvalue casts.
7775 if (auto *CE = dyn_cast<CastExpr>(Init)) {
7776 switch (CE->getCastKind()) {
7777 case CK_LValueToRValue:
7778 // If we can match the lvalue to a const object, we can look at its
7779 // initializer.
7780 Path.push_back({IndirectLocalPathEntry::LValToRVal, CE});
7781 return visitLocalsRetainedByReferenceBinding(
7782 Path, Init, RK_ReferenceBinding,
7783 [&](IndirectLocalPath &Path, Local L, ReferenceKind RK) -> bool {
7784 if (auto *DRE = dyn_cast<DeclRefExpr>(L)) {
7785 auto *VD = dyn_cast<VarDecl>(DRE->getDecl());
7786 if (VD && VD->getType().isConstQualified() && VD->getInit() &&
7787 !isVarOnPath(Path, VD)) {
7788 Path.push_back({IndirectLocalPathEntry::VarInit, DRE, VD});
7789 visitLocalsRetainedByInitializer(Path, VD->getInit(), Visit, true,
7790 EnableLifetimeWarnings);
7791 }
7792 } else if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(L)) {
7793 if (MTE->getType().isConstQualified())
7794 visitLocalsRetainedByInitializer(Path, MTE->getSubExpr(), Visit,
7795 true, EnableLifetimeWarnings);
7796 }
7797 return false;
7798 }, EnableLifetimeWarnings);
7799
7800 // We assume that objects can be retained by pointers cast to integers,
7801 // but not if the integer is cast to floating-point type or to _Complex.
7802 // We assume that casts to 'bool' do not preserve enough information to
7803 // retain a local object.
7804 case CK_NoOp:
7805 case CK_BitCast:
7806 case CK_BaseToDerived:
7807 case CK_DerivedToBase:
7808 case CK_UncheckedDerivedToBase:
7809 case CK_Dynamic:
7810 case CK_ToUnion:
7811 case CK_UserDefinedConversion:
7812 case CK_ConstructorConversion:
7813 case CK_IntegralToPointer:
7814 case CK_PointerToIntegral:
7815 case CK_VectorSplat:
7816 case CK_IntegralCast:
7817 case CK_CPointerToObjCPointerCast:
7818 case CK_BlockPointerToObjCPointerCast:
7819 case CK_AnyPointerToBlockPointerCast:
7820 case CK_AddressSpaceConversion:
7821 break;
7822
7823 case CK_ArrayToPointerDecay:
7824 // Model array-to-pointer decay as taking the address of the array
7825 // lvalue.
7826 Path.push_back({IndirectLocalPathEntry::AddressOf, CE});
7827 return visitLocalsRetainedByReferenceBinding(Path, CE->getSubExpr(),
7828 RK_ReferenceBinding, Visit,
7829 EnableLifetimeWarnings);
7830
7831 default:
7832 return;
7833 }
7834
7835 Init = CE->getSubExpr();
7836 }
7837 } while (Old != Init);
7838
7839 // C++17 [dcl.init.list]p6:
7840 // initializing an initializer_list object from the array extends the
7841 // lifetime of the array exactly like binding a reference to a temporary.
7842 if (auto *ILE = dyn_cast<CXXStdInitializerListExpr>(Init))
7843 return visitLocalsRetainedByReferenceBinding(Path, ILE->getSubExpr(),
7844 RK_StdInitializerList, Visit,
7845 EnableLifetimeWarnings);
7846
7847 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
7848 // We already visited the elements of this initializer list while
7849 // performing the initialization. Don't visit them again unless we've
7850 // changed the lifetime of the initialized entity.
7851 if (!RevisitSubinits)
7852 return;
7853
7854 if (ILE->isTransparent())
7855 return visitLocalsRetainedByInitializer(Path, ILE->getInit(0), Visit,
7856 RevisitSubinits,
7857 EnableLifetimeWarnings);
7858
7859 if (ILE->getType()->isArrayType()) {
7860 for (unsigned I = 0, N = ILE->getNumInits(); I != N; ++I)
7861 visitLocalsRetainedByInitializer(Path, ILE->getInit(I), Visit,
7862 RevisitSubinits,
7863 EnableLifetimeWarnings);
7864 return;
7865 }
7866
7867 if (CXXRecordDecl *RD = ILE->getType()->getAsCXXRecordDecl()) {
7868 assert(RD->isAggregate() && "aggregate init on non-aggregate");
7869
7870 // If we lifetime-extend a braced initializer which is initializing an
7871 // aggregate, and that aggregate contains reference members which are
7872 // bound to temporaries, those temporaries are also lifetime-extended.
7873 if (RD->isUnion() && ILE->getInitializedFieldInUnion() &&
7874 ILE->getInitializedFieldInUnion()->getType()->isReferenceType())
7875 visitLocalsRetainedByReferenceBinding(Path, ILE->getInit(0),
7876 RK_ReferenceBinding, Visit,
7877 EnableLifetimeWarnings);
7878 else {
7879 unsigned Index = 0;
7880 for (; Index < RD->getNumBases() && Index < ILE->getNumInits(); ++Index)
7881 visitLocalsRetainedByInitializer(Path, ILE->getInit(Index), Visit,
7882 RevisitSubinits,
7883 EnableLifetimeWarnings);
7884 for (const auto *I : RD->fields()) {
7885 if (Index >= ILE->getNumInits())
7886 break;
7887 if (I->isUnnamedBitfield())
7888 continue;
7889 Expr *SubInit = ILE->getInit(Index);
7890 if (I->getType()->isReferenceType())
7891 visitLocalsRetainedByReferenceBinding(Path, SubInit,
7892 RK_ReferenceBinding, Visit,
7893 EnableLifetimeWarnings);
7894 else
7895 // This might be either aggregate-initialization of a member or
7896 // initialization of a std::initializer_list object. Regardless,
7897 // we should recursively lifetime-extend that initializer.
7898 visitLocalsRetainedByInitializer(Path, SubInit, Visit,
7899 RevisitSubinits,
7900 EnableLifetimeWarnings);
7901 ++Index;
7902 }
7903 }
7904 }
7905 return;
7906 }
7907
7908 // The lifetime of an init-capture is that of the closure object constructed
7909 // by a lambda-expression.
7910 if (auto *LE = dyn_cast<LambdaExpr>(Init)) {
7911 LambdaExpr::capture_iterator CapI = LE->capture_begin();
7912 for (Expr *E : LE->capture_inits()) {
7913 assert(CapI != LE->capture_end());
7914 const LambdaCapture &Cap = *CapI++;
7915 if (!E)
7916 continue;
7917 if (Cap.capturesVariable())
7918 Path.push_back({IndirectLocalPathEntry::LambdaCaptureInit, E, &Cap});
7919 if (E->isGLValue())
7920 visitLocalsRetainedByReferenceBinding(Path, E, RK_ReferenceBinding,
7921 Visit, EnableLifetimeWarnings);
7922 else
7923 visitLocalsRetainedByInitializer(Path, E, Visit, true,
7924 EnableLifetimeWarnings);
7925 if (Cap.capturesVariable())
7926 Path.pop_back();
7927 }
7928 }
7929
7930 // Assume that a copy or move from a temporary references the same objects
7931 // that the temporary does.
7932 if (auto *CCE = dyn_cast<CXXConstructExpr>(Init)) {
7933 if (CCE->getConstructor()->isCopyOrMoveConstructor()) {
7934 if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(CCE->getArg(0))) {
7935 Expr *Arg = MTE->getSubExpr();
7936 Path.push_back({IndirectLocalPathEntry::TemporaryCopy, Arg,
7937 CCE->getConstructor()});
7938 visitLocalsRetainedByInitializer(Path, Arg, Visit, true,
7939 /*EnableLifetimeWarnings*/false);
7940 Path.pop_back();
7941 }
7942 }
7943 }
7944
7945 if (isa<CallExpr>(Init) || isa<CXXConstructExpr>(Init)) {
7946 if (EnableLifetimeWarnings)
7947 handleGslAnnotatedTypes(Path, Init, Visit);
7948 return visitLifetimeBoundArguments(Path, Init, Visit);
7949 }
7950
7951 switch (Init->getStmtClass()) {
7952 case Stmt::UnaryOperatorClass: {
7953 auto *UO = cast<UnaryOperator>(Init);
7954 // If the initializer is the address of a local, we could have a lifetime
7955 // problem.
7956 if (UO->getOpcode() == UO_AddrOf) {
7957 // If this is &rvalue, then it's ill-formed and we have already diagnosed
7958 // it. Don't produce a redundant warning about the lifetime of the
7959 // temporary.
7960 if (isa<MaterializeTemporaryExpr>(UO->getSubExpr()))
7961 return;
7962
7963 Path.push_back({IndirectLocalPathEntry::AddressOf, UO});
7964 visitLocalsRetainedByReferenceBinding(Path, UO->getSubExpr(),
7965 RK_ReferenceBinding, Visit,
7966 EnableLifetimeWarnings);
7967 }
7968 break;
7969 }
7970
7971 case Stmt::BinaryOperatorClass: {
7972 // Handle pointer arithmetic.
7973 auto *BO = cast<BinaryOperator>(Init);
7974 BinaryOperatorKind BOK = BO->getOpcode();
7975 if (!BO->getType()->isPointerType() || (BOK != BO_Add && BOK != BO_Sub))
7976 break;
7977
7978 if (BO->getLHS()->getType()->isPointerType())
7979 visitLocalsRetainedByInitializer(Path, BO->getLHS(), Visit, true,
7980 EnableLifetimeWarnings);
7981 else if (BO->getRHS()->getType()->isPointerType())
7982 visitLocalsRetainedByInitializer(Path, BO->getRHS(), Visit, true,
7983 EnableLifetimeWarnings);
7984 break;
7985 }
7986
7987 case Stmt::ConditionalOperatorClass:
7988 case Stmt::BinaryConditionalOperatorClass: {
7989 auto *C = cast<AbstractConditionalOperator>(Init);
7990 // In C++, we can have a throw-expression operand, which has 'void' type
7991 // and isn't interesting from a lifetime perspective.
7992 if (!C->getTrueExpr()->getType()->isVoidType())
7993 visitLocalsRetainedByInitializer(Path, C->getTrueExpr(), Visit, true,
7994 EnableLifetimeWarnings);
7995 if (!C->getFalseExpr()->getType()->isVoidType())
7996 visitLocalsRetainedByInitializer(Path, C->getFalseExpr(), Visit, true,
7997 EnableLifetimeWarnings);
7998 break;
7999 }
8000
8001 case Stmt::BlockExprClass:
8002 if (cast<BlockExpr>(Init)->getBlockDecl()->hasCaptures()) {
8003 // This is a local block, whose lifetime is that of the function.
8004 Visit(Path, Local(cast<BlockExpr>(Init)), RK_ReferenceBinding);
8005 }
8006 break;
8007
8008 case Stmt::AddrLabelExprClass:
8009 // We want to warn if the address of a label would escape the function.
8010 Visit(Path, Local(cast<AddrLabelExpr>(Init)), RK_ReferenceBinding);
8011 break;
8012
8013 default:
8014 break;
8015 }
8016 }
8017
8018 /// Whether a path to an object supports lifetime extension.
8019 enum PathLifetimeKind {
8020 /// Lifetime-extend along this path.
8021 Extend,
8022 /// We should lifetime-extend, but we don't because (due to technical
8023 /// limitations) we can't. This happens for default member initializers,
8024 /// which we don't clone for every use, so we don't have a unique
8025 /// MaterializeTemporaryExpr to update.
8026 ShouldExtend,
8027 /// Do not lifetime extend along this path.
8028 NoExtend
8029 };
8030
8031 /// Determine whether this is an indirect path to a temporary that we are
8032 /// supposed to lifetime-extend along.
8033 static PathLifetimeKind
shouldLifetimeExtendThroughPath(const IndirectLocalPath & Path)8034 shouldLifetimeExtendThroughPath(const IndirectLocalPath &Path) {
8035 PathLifetimeKind Kind = PathLifetimeKind::Extend;
8036 for (auto Elem : Path) {
8037 if (Elem.Kind == IndirectLocalPathEntry::DefaultInit)
8038 Kind = PathLifetimeKind::ShouldExtend;
8039 else if (Elem.Kind != IndirectLocalPathEntry::LambdaCaptureInit)
8040 return PathLifetimeKind::NoExtend;
8041 }
8042 return Kind;
8043 }
8044
8045 /// Find the range for the first interesting entry in the path at or after I.
nextPathEntryRange(const IndirectLocalPath & Path,unsigned I,Expr * E)8046 static SourceRange nextPathEntryRange(const IndirectLocalPath &Path, unsigned I,
8047 Expr *E) {
8048 for (unsigned N = Path.size(); I != N; ++I) {
8049 switch (Path[I].Kind) {
8050 case IndirectLocalPathEntry::AddressOf:
8051 case IndirectLocalPathEntry::LValToRVal:
8052 case IndirectLocalPathEntry::LifetimeBoundCall:
8053 case IndirectLocalPathEntry::TemporaryCopy:
8054 case IndirectLocalPathEntry::GslReferenceInit:
8055 case IndirectLocalPathEntry::GslPointerInit:
8056 // These exist primarily to mark the path as not permitting or
8057 // supporting lifetime extension.
8058 break;
8059
8060 case IndirectLocalPathEntry::VarInit:
8061 if (cast<VarDecl>(Path[I].D)->isImplicit())
8062 return SourceRange();
8063 [[fallthrough]];
8064 case IndirectLocalPathEntry::DefaultInit:
8065 return Path[I].E->getSourceRange();
8066
8067 case IndirectLocalPathEntry::LambdaCaptureInit:
8068 if (!Path[I].Capture->capturesVariable())
8069 continue;
8070 return Path[I].E->getSourceRange();
8071 }
8072 }
8073 return E->getSourceRange();
8074 }
8075
pathOnlyInitializesGslPointer(IndirectLocalPath & Path)8076 static bool pathOnlyInitializesGslPointer(IndirectLocalPath &Path) {
8077 for (const auto &It : llvm::reverse(Path)) {
8078 if (It.Kind == IndirectLocalPathEntry::VarInit)
8079 continue;
8080 if (It.Kind == IndirectLocalPathEntry::AddressOf)
8081 continue;
8082 if (It.Kind == IndirectLocalPathEntry::LifetimeBoundCall)
8083 continue;
8084 return It.Kind == IndirectLocalPathEntry::GslPointerInit ||
8085 It.Kind == IndirectLocalPathEntry::GslReferenceInit;
8086 }
8087 return false;
8088 }
8089
checkInitializerLifetime(const InitializedEntity & Entity,Expr * Init)8090 void Sema::checkInitializerLifetime(const InitializedEntity &Entity,
8091 Expr *Init) {
8092 LifetimeResult LR = getEntityLifetime(&Entity);
8093 LifetimeKind LK = LR.getInt();
8094 const InitializedEntity *ExtendingEntity = LR.getPointer();
8095
8096 // If this entity doesn't have an interesting lifetime, don't bother looking
8097 // for temporaries within its initializer.
8098 if (LK == LK_FullExpression)
8099 return;
8100
8101 auto TemporaryVisitor = [&](IndirectLocalPath &Path, Local L,
8102 ReferenceKind RK) -> bool {
8103 SourceRange DiagRange = nextPathEntryRange(Path, 0, L);
8104 SourceLocation DiagLoc = DiagRange.getBegin();
8105
8106 auto *MTE = dyn_cast<MaterializeTemporaryExpr>(L);
8107
8108 bool IsGslPtrInitWithGslTempOwner = false;
8109 bool IsLocalGslOwner = false;
8110 if (pathOnlyInitializesGslPointer(Path)) {
8111 if (isa<DeclRefExpr>(L)) {
8112 // We do not want to follow the references when returning a pointer originating
8113 // from a local owner to avoid the following false positive:
8114 // int &p = *localUniquePtr;
8115 // someContainer.add(std::move(localUniquePtr));
8116 // return p;
8117 IsLocalGslOwner = isRecordWithAttr<OwnerAttr>(L->getType());
8118 if (pathContainsInit(Path) || !IsLocalGslOwner)
8119 return false;
8120 } else {
8121 IsGslPtrInitWithGslTempOwner = MTE && !MTE->getExtendingDecl() &&
8122 isRecordWithAttr<OwnerAttr>(MTE->getType());
8123 // Skipping a chain of initializing gsl::Pointer annotated objects.
8124 // We are looking only for the final source to find out if it was
8125 // a local or temporary owner or the address of a local variable/param.
8126 if (!IsGslPtrInitWithGslTempOwner)
8127 return true;
8128 }
8129 }
8130
8131 switch (LK) {
8132 case LK_FullExpression:
8133 llvm_unreachable("already handled this");
8134
8135 case LK_Extended: {
8136 if (!MTE) {
8137 // The initialized entity has lifetime beyond the full-expression,
8138 // and the local entity does too, so don't warn.
8139 //
8140 // FIXME: We should consider warning if a static / thread storage
8141 // duration variable retains an automatic storage duration local.
8142 return false;
8143 }
8144
8145 if (IsGslPtrInitWithGslTempOwner && DiagLoc.isValid()) {
8146 Diag(DiagLoc, diag::warn_dangling_lifetime_pointer) << DiagRange;
8147 return false;
8148 }
8149
8150 switch (shouldLifetimeExtendThroughPath(Path)) {
8151 case PathLifetimeKind::Extend:
8152 // Update the storage duration of the materialized temporary.
8153 // FIXME: Rebuild the expression instead of mutating it.
8154 MTE->setExtendingDecl(ExtendingEntity->getDecl(),
8155 ExtendingEntity->allocateManglingNumber());
8156 // Also visit the temporaries lifetime-extended by this initializer.
8157 return true;
8158
8159 case PathLifetimeKind::ShouldExtend:
8160 // We're supposed to lifetime-extend the temporary along this path (per
8161 // the resolution of DR1815), but we don't support that yet.
8162 //
8163 // FIXME: Properly handle this situation. Perhaps the easiest approach
8164 // would be to clone the initializer expression on each use that would
8165 // lifetime extend its temporaries.
8166 Diag(DiagLoc, diag::warn_unsupported_lifetime_extension)
8167 << RK << DiagRange;
8168 break;
8169
8170 case PathLifetimeKind::NoExtend:
8171 // If the path goes through the initialization of a variable or field,
8172 // it can't possibly reach a temporary created in this full-expression.
8173 // We will have already diagnosed any problems with the initializer.
8174 if (pathContainsInit(Path))
8175 return false;
8176
8177 Diag(DiagLoc, diag::warn_dangling_variable)
8178 << RK << !Entity.getParent()
8179 << ExtendingEntity->getDecl()->isImplicit()
8180 << ExtendingEntity->getDecl() << Init->isGLValue() << DiagRange;
8181 break;
8182 }
8183 break;
8184 }
8185
8186 case LK_MemInitializer: {
8187 if (isa<MaterializeTemporaryExpr>(L)) {
8188 // Under C++ DR1696, if a mem-initializer (or a default member
8189 // initializer used by the absence of one) would lifetime-extend a
8190 // temporary, the program is ill-formed.
8191 if (auto *ExtendingDecl =
8192 ExtendingEntity ? ExtendingEntity->getDecl() : nullptr) {
8193 if (IsGslPtrInitWithGslTempOwner) {
8194 Diag(DiagLoc, diag::warn_dangling_lifetime_pointer_member)
8195 << ExtendingDecl << DiagRange;
8196 Diag(ExtendingDecl->getLocation(),
8197 diag::note_ref_or_ptr_member_declared_here)
8198 << true;
8199 return false;
8200 }
8201 bool IsSubobjectMember = ExtendingEntity != &Entity;
8202 Diag(DiagLoc, shouldLifetimeExtendThroughPath(Path) !=
8203 PathLifetimeKind::NoExtend
8204 ? diag::err_dangling_member
8205 : diag::warn_dangling_member)
8206 << ExtendingDecl << IsSubobjectMember << RK << DiagRange;
8207 // Don't bother adding a note pointing to the field if we're inside
8208 // its default member initializer; our primary diagnostic points to
8209 // the same place in that case.
8210 if (Path.empty() ||
8211 Path.back().Kind != IndirectLocalPathEntry::DefaultInit) {
8212 Diag(ExtendingDecl->getLocation(),
8213 diag::note_lifetime_extending_member_declared_here)
8214 << RK << IsSubobjectMember;
8215 }
8216 } else {
8217 // We have a mem-initializer but no particular field within it; this
8218 // is either a base class or a delegating initializer directly
8219 // initializing the base-class from something that doesn't live long
8220 // enough.
8221 //
8222 // FIXME: Warn on this.
8223 return false;
8224 }
8225 } else {
8226 // Paths via a default initializer can only occur during error recovery
8227 // (there's no other way that a default initializer can refer to a
8228 // local). Don't produce a bogus warning on those cases.
8229 if (pathContainsInit(Path))
8230 return false;
8231
8232 // Suppress false positives for code like the one below:
8233 // Ctor(unique_ptr<T> up) : member(*up), member2(move(up)) {}
8234 if (IsLocalGslOwner && pathOnlyInitializesGslPointer(Path))
8235 return false;
8236
8237 auto *DRE = dyn_cast<DeclRefExpr>(L);
8238 auto *VD = DRE ? dyn_cast<VarDecl>(DRE->getDecl()) : nullptr;
8239 if (!VD) {
8240 // A member was initialized to a local block.
8241 // FIXME: Warn on this.
8242 return false;
8243 }
8244
8245 if (auto *Member =
8246 ExtendingEntity ? ExtendingEntity->getDecl() : nullptr) {
8247 bool IsPointer = !Member->getType()->isReferenceType();
8248 Diag(DiagLoc, IsPointer ? diag::warn_init_ptr_member_to_parameter_addr
8249 : diag::warn_bind_ref_member_to_parameter)
8250 << Member << VD << isa<ParmVarDecl>(VD) << DiagRange;
8251 Diag(Member->getLocation(),
8252 diag::note_ref_or_ptr_member_declared_here)
8253 << (unsigned)IsPointer;
8254 }
8255 }
8256 break;
8257 }
8258
8259 case LK_New:
8260 if (isa<MaterializeTemporaryExpr>(L)) {
8261 if (IsGslPtrInitWithGslTempOwner)
8262 Diag(DiagLoc, diag::warn_dangling_lifetime_pointer) << DiagRange;
8263 else
8264 Diag(DiagLoc, RK == RK_ReferenceBinding
8265 ? diag::warn_new_dangling_reference
8266 : diag::warn_new_dangling_initializer_list)
8267 << !Entity.getParent() << DiagRange;
8268 } else {
8269 // We can't determine if the allocation outlives the local declaration.
8270 return false;
8271 }
8272 break;
8273
8274 case LK_Return:
8275 case LK_StmtExprResult:
8276 if (auto *DRE = dyn_cast<DeclRefExpr>(L)) {
8277 // We can't determine if the local variable outlives the statement
8278 // expression.
8279 if (LK == LK_StmtExprResult)
8280 return false;
8281 Diag(DiagLoc, diag::warn_ret_stack_addr_ref)
8282 << Entity.getType()->isReferenceType() << DRE->getDecl()
8283 << isa<ParmVarDecl>(DRE->getDecl()) << DiagRange;
8284 } else if (isa<BlockExpr>(L)) {
8285 Diag(DiagLoc, diag::err_ret_local_block) << DiagRange;
8286 } else if (isa<AddrLabelExpr>(L)) {
8287 // Don't warn when returning a label from a statement expression.
8288 // Leaving the scope doesn't end its lifetime.
8289 if (LK == LK_StmtExprResult)
8290 return false;
8291 Diag(DiagLoc, diag::warn_ret_addr_label) << DiagRange;
8292 } else {
8293 Diag(DiagLoc, diag::warn_ret_local_temp_addr_ref)
8294 << Entity.getType()->isReferenceType() << DiagRange;
8295 }
8296 break;
8297 }
8298
8299 for (unsigned I = 0; I != Path.size(); ++I) {
8300 auto Elem = Path[I];
8301
8302 switch (Elem.Kind) {
8303 case IndirectLocalPathEntry::AddressOf:
8304 case IndirectLocalPathEntry::LValToRVal:
8305 // These exist primarily to mark the path as not permitting or
8306 // supporting lifetime extension.
8307 break;
8308
8309 case IndirectLocalPathEntry::LifetimeBoundCall:
8310 case IndirectLocalPathEntry::TemporaryCopy:
8311 case IndirectLocalPathEntry::GslPointerInit:
8312 case IndirectLocalPathEntry::GslReferenceInit:
8313 // FIXME: Consider adding a note for these.
8314 break;
8315
8316 case IndirectLocalPathEntry::DefaultInit: {
8317 auto *FD = cast<FieldDecl>(Elem.D);
8318 Diag(FD->getLocation(), diag::note_init_with_default_member_initializer)
8319 << FD << nextPathEntryRange(Path, I + 1, L);
8320 break;
8321 }
8322
8323 case IndirectLocalPathEntry::VarInit: {
8324 const VarDecl *VD = cast<VarDecl>(Elem.D);
8325 Diag(VD->getLocation(), diag::note_local_var_initializer)
8326 << VD->getType()->isReferenceType()
8327 << VD->isImplicit() << VD->getDeclName()
8328 << nextPathEntryRange(Path, I + 1, L);
8329 break;
8330 }
8331
8332 case IndirectLocalPathEntry::LambdaCaptureInit:
8333 if (!Elem.Capture->capturesVariable())
8334 break;
8335 // FIXME: We can't easily tell apart an init-capture from a nested
8336 // capture of an init-capture.
8337 const ValueDecl *VD = Elem.Capture->getCapturedVar();
8338 Diag(Elem.Capture->getLocation(), diag::note_lambda_capture_initializer)
8339 << VD << VD->isInitCapture() << Elem.Capture->isExplicit()
8340 << (Elem.Capture->getCaptureKind() == LCK_ByRef) << VD
8341 << nextPathEntryRange(Path, I + 1, L);
8342 break;
8343 }
8344 }
8345
8346 // We didn't lifetime-extend, so don't go any further; we don't need more
8347 // warnings or errors on inner temporaries within this one's initializer.
8348 return false;
8349 };
8350
8351 bool EnableLifetimeWarnings = !getDiagnostics().isIgnored(
8352 diag::warn_dangling_lifetime_pointer, SourceLocation());
8353 llvm::SmallVector<IndirectLocalPathEntry, 8> Path;
8354 if (Init->isGLValue())
8355 visitLocalsRetainedByReferenceBinding(Path, Init, RK_ReferenceBinding,
8356 TemporaryVisitor,
8357 EnableLifetimeWarnings);
8358 else
8359 visitLocalsRetainedByInitializer(Path, Init, TemporaryVisitor, false,
8360 EnableLifetimeWarnings);
8361 }
8362
8363 static void DiagnoseNarrowingInInitList(Sema &S,
8364 const ImplicitConversionSequence &ICS,
8365 QualType PreNarrowingType,
8366 QualType EntityType,
8367 const Expr *PostInit);
8368
8369 /// Provide warnings when std::move is used on construction.
CheckMoveOnConstruction(Sema & S,const Expr * InitExpr,bool IsReturnStmt)8370 static void CheckMoveOnConstruction(Sema &S, const Expr *InitExpr,
8371 bool IsReturnStmt) {
8372 if (!InitExpr)
8373 return;
8374
8375 if (S.inTemplateInstantiation())
8376 return;
8377
8378 QualType DestType = InitExpr->getType();
8379 if (!DestType->isRecordType())
8380 return;
8381
8382 unsigned DiagID = 0;
8383 if (IsReturnStmt) {
8384 const CXXConstructExpr *CCE =
8385 dyn_cast<CXXConstructExpr>(InitExpr->IgnoreParens());
8386 if (!CCE || CCE->getNumArgs() != 1)
8387 return;
8388
8389 if (!CCE->getConstructor()->isCopyOrMoveConstructor())
8390 return;
8391
8392 InitExpr = CCE->getArg(0)->IgnoreImpCasts();
8393 }
8394
8395 // Find the std::move call and get the argument.
8396 const CallExpr *CE = dyn_cast<CallExpr>(InitExpr->IgnoreParens());
8397 if (!CE || !CE->isCallToStdMove())
8398 return;
8399
8400 const Expr *Arg = CE->getArg(0)->IgnoreImplicit();
8401
8402 if (IsReturnStmt) {
8403 const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg->IgnoreParenImpCasts());
8404 if (!DRE || DRE->refersToEnclosingVariableOrCapture())
8405 return;
8406
8407 const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl());
8408 if (!VD || !VD->hasLocalStorage())
8409 return;
8410
8411 // __block variables are not moved implicitly.
8412 if (VD->hasAttr<BlocksAttr>())
8413 return;
8414
8415 QualType SourceType = VD->getType();
8416 if (!SourceType->isRecordType())
8417 return;
8418
8419 if (!S.Context.hasSameUnqualifiedType(DestType, SourceType)) {
8420 return;
8421 }
8422
8423 // If we're returning a function parameter, copy elision
8424 // is not possible.
8425 if (isa<ParmVarDecl>(VD))
8426 DiagID = diag::warn_redundant_move_on_return;
8427 else
8428 DiagID = diag::warn_pessimizing_move_on_return;
8429 } else {
8430 DiagID = diag::warn_pessimizing_move_on_initialization;
8431 const Expr *ArgStripped = Arg->IgnoreImplicit()->IgnoreParens();
8432 if (!ArgStripped->isPRValue() || !ArgStripped->getType()->isRecordType())
8433 return;
8434 }
8435
8436 S.Diag(CE->getBeginLoc(), DiagID);
8437
8438 // Get all the locations for a fix-it. Don't emit the fix-it if any location
8439 // is within a macro.
8440 SourceLocation CallBegin = CE->getCallee()->getBeginLoc();
8441 if (CallBegin.isMacroID())
8442 return;
8443 SourceLocation RParen = CE->getRParenLoc();
8444 if (RParen.isMacroID())
8445 return;
8446 SourceLocation LParen;
8447 SourceLocation ArgLoc = Arg->getBeginLoc();
8448
8449 // Special testing for the argument location. Since the fix-it needs the
8450 // location right before the argument, the argument location can be in a
8451 // macro only if it is at the beginning of the macro.
8452 while (ArgLoc.isMacroID() &&
8453 S.getSourceManager().isAtStartOfImmediateMacroExpansion(ArgLoc)) {
8454 ArgLoc = S.getSourceManager().getImmediateExpansionRange(ArgLoc).getBegin();
8455 }
8456
8457 if (LParen.isMacroID())
8458 return;
8459
8460 LParen = ArgLoc.getLocWithOffset(-1);
8461
8462 S.Diag(CE->getBeginLoc(), diag::note_remove_move)
8463 << FixItHint::CreateRemoval(SourceRange(CallBegin, LParen))
8464 << FixItHint::CreateRemoval(SourceRange(RParen, RParen));
8465 }
8466
CheckForNullPointerDereference(Sema & S,const Expr * E)8467 static void CheckForNullPointerDereference(Sema &S, const Expr *E) {
8468 // Check to see if we are dereferencing a null pointer. If so, this is
8469 // undefined behavior, so warn about it. This only handles the pattern
8470 // "*null", which is a very syntactic check.
8471 if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E->IgnoreParenCasts()))
8472 if (UO->getOpcode() == UO_Deref &&
8473 UO->getSubExpr()->IgnoreParenCasts()->
8474 isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull)) {
8475 S.DiagRuntimeBehavior(UO->getOperatorLoc(), UO,
8476 S.PDiag(diag::warn_binding_null_to_reference)
8477 << UO->getSubExpr()->getSourceRange());
8478 }
8479 }
8480
8481 MaterializeTemporaryExpr *
CreateMaterializeTemporaryExpr(QualType T,Expr * Temporary,bool BoundToLvalueReference)8482 Sema::CreateMaterializeTemporaryExpr(QualType T, Expr *Temporary,
8483 bool BoundToLvalueReference) {
8484 auto MTE = new (Context)
8485 MaterializeTemporaryExpr(T, Temporary, BoundToLvalueReference);
8486
8487 // Order an ExprWithCleanups for lifetime marks.
8488 //
8489 // TODO: It'll be good to have a single place to check the access of the
8490 // destructor and generate ExprWithCleanups for various uses. Currently these
8491 // are done in both CreateMaterializeTemporaryExpr and MaybeBindToTemporary,
8492 // but there may be a chance to merge them.
8493 Cleanup.setExprNeedsCleanups(false);
8494 return MTE;
8495 }
8496
TemporaryMaterializationConversion(Expr * E)8497 ExprResult Sema::TemporaryMaterializationConversion(Expr *E) {
8498 // In C++98, we don't want to implicitly create an xvalue.
8499 // FIXME: This means that AST consumers need to deal with "prvalues" that
8500 // denote materialized temporaries. Maybe we should add another ValueKind
8501 // for "xvalue pretending to be a prvalue" for C++98 support.
8502 if (!E->isPRValue() || !getLangOpts().CPlusPlus11)
8503 return E;
8504
8505 // C++1z [conv.rval]/1: T shall be a complete type.
8506 // FIXME: Does this ever matter (can we form a prvalue of incomplete type)?
8507 // If so, we should check for a non-abstract class type here too.
8508 QualType T = E->getType();
8509 if (RequireCompleteType(E->getExprLoc(), T, diag::err_incomplete_type))
8510 return ExprError();
8511
8512 return CreateMaterializeTemporaryExpr(E->getType(), E, false);
8513 }
8514
PerformQualificationConversion(Expr * E,QualType Ty,ExprValueKind VK,CheckedConversionKind CCK)8515 ExprResult Sema::PerformQualificationConversion(Expr *E, QualType Ty,
8516 ExprValueKind VK,
8517 CheckedConversionKind CCK) {
8518
8519 CastKind CK = CK_NoOp;
8520
8521 if (VK == VK_PRValue) {
8522 auto PointeeTy = Ty->getPointeeType();
8523 auto ExprPointeeTy = E->getType()->getPointeeType();
8524 if (!PointeeTy.isNull() &&
8525 PointeeTy.getAddressSpace() != ExprPointeeTy.getAddressSpace())
8526 CK = CK_AddressSpaceConversion;
8527 } else if (Ty.getAddressSpace() != E->getType().getAddressSpace()) {
8528 CK = CK_AddressSpaceConversion;
8529 }
8530
8531 return ImpCastExprToType(E, Ty, CK, VK, /*BasePath=*/nullptr, CCK);
8532 }
8533
Perform(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Args,QualType * ResultType)8534 ExprResult InitializationSequence::Perform(Sema &S,
8535 const InitializedEntity &Entity,
8536 const InitializationKind &Kind,
8537 MultiExprArg Args,
8538 QualType *ResultType) {
8539 if (Failed()) {
8540 Diagnose(S, Entity, Kind, Args);
8541 return ExprError();
8542 }
8543 if (!ZeroInitializationFixit.empty()) {
8544 const Decl *D = Entity.getDecl();
8545 const auto *VD = dyn_cast_or_null<VarDecl>(D);
8546 QualType DestType = Entity.getType();
8547
8548 // The initialization would have succeeded with this fixit. Since the fixit
8549 // is on the error, we need to build a valid AST in this case, so this isn't
8550 // handled in the Failed() branch above.
8551 if (!DestType->isRecordType() && VD && VD->isConstexpr()) {
8552 // Use a more useful diagnostic for constexpr variables.
8553 S.Diag(Kind.getLocation(), diag::err_constexpr_var_requires_const_init)
8554 << VD
8555 << FixItHint::CreateInsertion(ZeroInitializationFixitLoc,
8556 ZeroInitializationFixit);
8557 } else {
8558 unsigned DiagID = diag::err_default_init_const;
8559 if (S.getLangOpts().MSVCCompat && D && D->hasAttr<SelectAnyAttr>())
8560 DiagID = diag::ext_default_init_const;
8561
8562 S.Diag(Kind.getLocation(), DiagID)
8563 << DestType << (bool)DestType->getAs<RecordType>()
8564 << FixItHint::CreateInsertion(ZeroInitializationFixitLoc,
8565 ZeroInitializationFixit);
8566 }
8567 }
8568
8569 if (getKind() == DependentSequence) {
8570 // If the declaration is a non-dependent, incomplete array type
8571 // that has an initializer, then its type will be completed once
8572 // the initializer is instantiated.
8573 if (ResultType && !Entity.getType()->isDependentType() &&
8574 Args.size() == 1) {
8575 QualType DeclType = Entity.getType();
8576 if (const IncompleteArrayType *ArrayT
8577 = S.Context.getAsIncompleteArrayType(DeclType)) {
8578 // FIXME: We don't currently have the ability to accurately
8579 // compute the length of an initializer list without
8580 // performing full type-checking of the initializer list
8581 // (since we have to determine where braces are implicitly
8582 // introduced and such). So, we fall back to making the array
8583 // type a dependently-sized array type with no specified
8584 // bound.
8585 if (isa<InitListExpr>((Expr *)Args[0])) {
8586 SourceRange Brackets;
8587
8588 // Scavange the location of the brackets from the entity, if we can.
8589 if (auto *DD = dyn_cast_or_null<DeclaratorDecl>(Entity.getDecl())) {
8590 if (TypeSourceInfo *TInfo = DD->getTypeSourceInfo()) {
8591 TypeLoc TL = TInfo->getTypeLoc();
8592 if (IncompleteArrayTypeLoc ArrayLoc =
8593 TL.getAs<IncompleteArrayTypeLoc>())
8594 Brackets = ArrayLoc.getBracketsRange();
8595 }
8596 }
8597
8598 *ResultType
8599 = S.Context.getDependentSizedArrayType(ArrayT->getElementType(),
8600 /*NumElts=*/nullptr,
8601 ArrayT->getSizeModifier(),
8602 ArrayT->getIndexTypeCVRQualifiers(),
8603 Brackets);
8604 }
8605
8606 }
8607 }
8608 if (Kind.getKind() == InitializationKind::IK_Direct &&
8609 !Kind.isExplicitCast()) {
8610 // Rebuild the ParenListExpr.
8611 SourceRange ParenRange = Kind.getParenOrBraceRange();
8612 return S.ActOnParenListExpr(ParenRange.getBegin(), ParenRange.getEnd(),
8613 Args);
8614 }
8615 assert(Kind.getKind() == InitializationKind::IK_Copy ||
8616 Kind.isExplicitCast() ||
8617 Kind.getKind() == InitializationKind::IK_DirectList);
8618 return ExprResult(Args[0]);
8619 }
8620
8621 // No steps means no initialization.
8622 if (Steps.empty())
8623 return ExprResult((Expr *)nullptr);
8624
8625 if (S.getLangOpts().CPlusPlus11 && Entity.getType()->isReferenceType() &&
8626 Args.size() == 1 && isa<InitListExpr>(Args[0]) &&
8627 !Entity.isParamOrTemplateParamKind()) {
8628 // Produce a C++98 compatibility warning if we are initializing a reference
8629 // from an initializer list. For parameters, we produce a better warning
8630 // elsewhere.
8631 Expr *Init = Args[0];
8632 S.Diag(Init->getBeginLoc(), diag::warn_cxx98_compat_reference_list_init)
8633 << Init->getSourceRange();
8634 }
8635
8636 if (S.getLangOpts().MicrosoftExt && Args.size() == 1 &&
8637 isa<PredefinedExpr>(Args[0]) && Entity.getType()->isArrayType()) {
8638 // Produce a Microsoft compatibility warning when initializing from a
8639 // predefined expression since MSVC treats predefined expressions as string
8640 // literals.
8641 Expr *Init = Args[0];
8642 S.Diag(Init->getBeginLoc(), diag::ext_init_from_predefined) << Init;
8643 }
8644
8645 // OpenCL v2.0 s6.13.11.1. atomic variables can be initialized in global scope
8646 QualType ETy = Entity.getType();
8647 bool HasGlobalAS = ETy.hasAddressSpace() &&
8648 ETy.getAddressSpace() == LangAS::opencl_global;
8649
8650 if (S.getLangOpts().OpenCLVersion >= 200 &&
8651 ETy->isAtomicType() && !HasGlobalAS &&
8652 Entity.getKind() == InitializedEntity::EK_Variable && Args.size() > 0) {
8653 S.Diag(Args[0]->getBeginLoc(), diag::err_opencl_atomic_init)
8654 << 1
8655 << SourceRange(Entity.getDecl()->getBeginLoc(), Args[0]->getEndLoc());
8656 return ExprError();
8657 }
8658
8659 QualType DestType = Entity.getType().getNonReferenceType();
8660 // FIXME: Ugly hack around the fact that Entity.getType() is not
8661 // the same as Entity.getDecl()->getType() in cases involving type merging,
8662 // and we want latter when it makes sense.
8663 if (ResultType)
8664 *ResultType = Entity.getDecl() ? Entity.getDecl()->getType() :
8665 Entity.getType();
8666
8667 ExprResult CurInit((Expr *)nullptr);
8668 SmallVector<Expr*, 4> ArrayLoopCommonExprs;
8669
8670 // HLSL allows vector initialization to function like list initialization, but
8671 // use the syntax of a C++-like constructor.
8672 bool IsHLSLVectorInit = S.getLangOpts().HLSL && DestType->isExtVectorType() &&
8673 isa<InitListExpr>(Args[0]);
8674 (void)IsHLSLVectorInit;
8675
8676 // For initialization steps that start with a single initializer,
8677 // grab the only argument out the Args and place it into the "current"
8678 // initializer.
8679 switch (Steps.front().Kind) {
8680 case SK_ResolveAddressOfOverloadedFunction:
8681 case SK_CastDerivedToBasePRValue:
8682 case SK_CastDerivedToBaseXValue:
8683 case SK_CastDerivedToBaseLValue:
8684 case SK_BindReference:
8685 case SK_BindReferenceToTemporary:
8686 case SK_FinalCopy:
8687 case SK_ExtraneousCopyToTemporary:
8688 case SK_UserConversion:
8689 case SK_QualificationConversionLValue:
8690 case SK_QualificationConversionXValue:
8691 case SK_QualificationConversionPRValue:
8692 case SK_FunctionReferenceConversion:
8693 case SK_AtomicConversion:
8694 case SK_ConversionSequence:
8695 case SK_ConversionSequenceNoNarrowing:
8696 case SK_ListInitialization:
8697 case SK_UnwrapInitList:
8698 case SK_RewrapInitList:
8699 case SK_CAssignment:
8700 case SK_StringInit:
8701 case SK_ObjCObjectConversion:
8702 case SK_ArrayLoopIndex:
8703 case SK_ArrayLoopInit:
8704 case SK_ArrayInit:
8705 case SK_GNUArrayInit:
8706 case SK_ParenthesizedArrayInit:
8707 case SK_PassByIndirectCopyRestore:
8708 case SK_PassByIndirectRestore:
8709 case SK_ProduceObjCObject:
8710 case SK_StdInitializerList:
8711 case SK_OCLSamplerInit:
8712 case SK_OCLZeroOpaqueType: {
8713 assert(Args.size() == 1 || IsHLSLVectorInit);
8714 CurInit = Args[0];
8715 if (!CurInit.get()) return ExprError();
8716 break;
8717 }
8718
8719 case SK_ConstructorInitialization:
8720 case SK_ConstructorInitializationFromList:
8721 case SK_StdInitializerListConstructorCall:
8722 case SK_ZeroInitialization:
8723 case SK_ParenthesizedListInit:
8724 break;
8725 }
8726
8727 // Promote from an unevaluated context to an unevaluated list context in
8728 // C++11 list-initialization; we need to instantiate entities usable in
8729 // constant expressions here in order to perform narrowing checks =(
8730 EnterExpressionEvaluationContext Evaluated(
8731 S, EnterExpressionEvaluationContext::InitList,
8732 CurInit.get() && isa<InitListExpr>(CurInit.get()));
8733
8734 // C++ [class.abstract]p2:
8735 // no objects of an abstract class can be created except as subobjects
8736 // of a class derived from it
8737 auto checkAbstractType = [&](QualType T) -> bool {
8738 if (Entity.getKind() == InitializedEntity::EK_Base ||
8739 Entity.getKind() == InitializedEntity::EK_Delegating)
8740 return false;
8741 return S.RequireNonAbstractType(Kind.getLocation(), T,
8742 diag::err_allocation_of_abstract_type);
8743 };
8744
8745 // Walk through the computed steps for the initialization sequence,
8746 // performing the specified conversions along the way.
8747 bool ConstructorInitRequiresZeroInit = false;
8748 for (step_iterator Step = step_begin(), StepEnd = step_end();
8749 Step != StepEnd; ++Step) {
8750 if (CurInit.isInvalid())
8751 return ExprError();
8752
8753 QualType SourceType = CurInit.get() ? CurInit.get()->getType() : QualType();
8754
8755 switch (Step->Kind) {
8756 case SK_ResolveAddressOfOverloadedFunction:
8757 // Overload resolution determined which function invoke; update the
8758 // initializer to reflect that choice.
8759 S.CheckAddressOfMemberAccess(CurInit.get(), Step->Function.FoundDecl);
8760 if (S.DiagnoseUseOfDecl(Step->Function.FoundDecl, Kind.getLocation()))
8761 return ExprError();
8762 CurInit = S.FixOverloadedFunctionReference(CurInit,
8763 Step->Function.FoundDecl,
8764 Step->Function.Function);
8765 // We might get back another placeholder expression if we resolved to a
8766 // builtin.
8767 if (!CurInit.isInvalid())
8768 CurInit = S.CheckPlaceholderExpr(CurInit.get());
8769 break;
8770
8771 case SK_CastDerivedToBasePRValue:
8772 case SK_CastDerivedToBaseXValue:
8773 case SK_CastDerivedToBaseLValue: {
8774 // We have a derived-to-base cast that produces either an rvalue or an
8775 // lvalue. Perform that cast.
8776
8777 CXXCastPath BasePath;
8778
8779 // Casts to inaccessible base classes are allowed with C-style casts.
8780 bool IgnoreBaseAccess = Kind.isCStyleOrFunctionalCast();
8781 if (S.CheckDerivedToBaseConversion(
8782 SourceType, Step->Type, CurInit.get()->getBeginLoc(),
8783 CurInit.get()->getSourceRange(), &BasePath, IgnoreBaseAccess))
8784 return ExprError();
8785
8786 ExprValueKind VK =
8787 Step->Kind == SK_CastDerivedToBaseLValue
8788 ? VK_LValue
8789 : (Step->Kind == SK_CastDerivedToBaseXValue ? VK_XValue
8790 : VK_PRValue);
8791 CurInit = ImplicitCastExpr::Create(S.Context, Step->Type,
8792 CK_DerivedToBase, CurInit.get(),
8793 &BasePath, VK, FPOptionsOverride());
8794 break;
8795 }
8796
8797 case SK_BindReference:
8798 // Reference binding does not have any corresponding ASTs.
8799
8800 // Check exception specifications
8801 if (S.CheckExceptionSpecCompatibility(CurInit.get(), DestType))
8802 return ExprError();
8803
8804 // We don't check for e.g. function pointers here, since address
8805 // availability checks should only occur when the function first decays
8806 // into a pointer or reference.
8807 if (CurInit.get()->getType()->isFunctionProtoType()) {
8808 if (auto *DRE = dyn_cast<DeclRefExpr>(CurInit.get()->IgnoreParens())) {
8809 if (auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl())) {
8810 if (!S.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true,
8811 DRE->getBeginLoc()))
8812 return ExprError();
8813 }
8814 }
8815 }
8816
8817 CheckForNullPointerDereference(S, CurInit.get());
8818 break;
8819
8820 case SK_BindReferenceToTemporary: {
8821 // Make sure the "temporary" is actually an rvalue.
8822 assert(CurInit.get()->isPRValue() && "not a temporary");
8823
8824 // Check exception specifications
8825 if (S.CheckExceptionSpecCompatibility(CurInit.get(), DestType))
8826 return ExprError();
8827
8828 QualType MTETy = Step->Type;
8829
8830 // When this is an incomplete array type (such as when this is
8831 // initializing an array of unknown bounds from an init list), use THAT
8832 // type instead so that we propagate the array bounds.
8833 if (MTETy->isIncompleteArrayType() &&
8834 !CurInit.get()->getType()->isIncompleteArrayType() &&
8835 S.Context.hasSameType(
8836 MTETy->getPointeeOrArrayElementType(),
8837 CurInit.get()->getType()->getPointeeOrArrayElementType()))
8838 MTETy = CurInit.get()->getType();
8839
8840 // Materialize the temporary into memory.
8841 MaterializeTemporaryExpr *MTE = S.CreateMaterializeTemporaryExpr(
8842 MTETy, CurInit.get(), Entity.getType()->isLValueReferenceType());
8843 CurInit = MTE;
8844
8845 // If we're extending this temporary to automatic storage duration -- we
8846 // need to register its cleanup during the full-expression's cleanups.
8847 if (MTE->getStorageDuration() == SD_Automatic &&
8848 MTE->getType().isDestructedType())
8849 S.Cleanup.setExprNeedsCleanups(true);
8850 break;
8851 }
8852
8853 case SK_FinalCopy:
8854 if (checkAbstractType(Step->Type))
8855 return ExprError();
8856
8857 // If the overall initialization is initializing a temporary, we already
8858 // bound our argument if it was necessary to do so. If not (if we're
8859 // ultimately initializing a non-temporary), our argument needs to be
8860 // bound since it's initializing a function parameter.
8861 // FIXME: This is a mess. Rationalize temporary destruction.
8862 if (!shouldBindAsTemporary(Entity))
8863 CurInit = S.MaybeBindToTemporary(CurInit.get());
8864 CurInit = CopyObject(S, Step->Type, Entity, CurInit,
8865 /*IsExtraneousCopy=*/false);
8866 break;
8867
8868 case SK_ExtraneousCopyToTemporary:
8869 CurInit = CopyObject(S, Step->Type, Entity, CurInit,
8870 /*IsExtraneousCopy=*/true);
8871 break;
8872
8873 case SK_UserConversion: {
8874 // We have a user-defined conversion that invokes either a constructor
8875 // or a conversion function.
8876 CastKind CastKind;
8877 FunctionDecl *Fn = Step->Function.Function;
8878 DeclAccessPair FoundFn = Step->Function.FoundDecl;
8879 bool HadMultipleCandidates = Step->Function.HadMultipleCandidates;
8880 bool CreatedObject = false;
8881 if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Fn)) {
8882 // Build a call to the selected constructor.
8883 SmallVector<Expr*, 8> ConstructorArgs;
8884 SourceLocation Loc = CurInit.get()->getBeginLoc();
8885
8886 // Determine the arguments required to actually perform the constructor
8887 // call.
8888 Expr *Arg = CurInit.get();
8889 if (S.CompleteConstructorCall(Constructor, Step->Type,
8890 MultiExprArg(&Arg, 1), Loc,
8891 ConstructorArgs))
8892 return ExprError();
8893
8894 // Build an expression that constructs a temporary.
8895 CurInit = S.BuildCXXConstructExpr(
8896 Loc, Step->Type, FoundFn, Constructor, ConstructorArgs,
8897 HadMultipleCandidates,
8898 /*ListInit*/ false,
8899 /*StdInitListInit*/ false,
8900 /*ZeroInit*/ false, CXXConstructionKind::Complete, SourceRange());
8901 if (CurInit.isInvalid())
8902 return ExprError();
8903
8904 S.CheckConstructorAccess(Kind.getLocation(), Constructor, FoundFn,
8905 Entity);
8906 if (S.DiagnoseUseOfDecl(FoundFn, Kind.getLocation()))
8907 return ExprError();
8908
8909 CastKind = CK_ConstructorConversion;
8910 CreatedObject = true;
8911 } else {
8912 // Build a call to the conversion function.
8913 CXXConversionDecl *Conversion = cast<CXXConversionDecl>(Fn);
8914 S.CheckMemberOperatorAccess(Kind.getLocation(), CurInit.get(), nullptr,
8915 FoundFn);
8916 if (S.DiagnoseUseOfDecl(FoundFn, Kind.getLocation()))
8917 return ExprError();
8918
8919 CurInit = S.BuildCXXMemberCallExpr(CurInit.get(), FoundFn, Conversion,
8920 HadMultipleCandidates);
8921 if (CurInit.isInvalid())
8922 return ExprError();
8923
8924 CastKind = CK_UserDefinedConversion;
8925 CreatedObject = Conversion->getReturnType()->isRecordType();
8926 }
8927
8928 if (CreatedObject && checkAbstractType(CurInit.get()->getType()))
8929 return ExprError();
8930
8931 CurInit = ImplicitCastExpr::Create(
8932 S.Context, CurInit.get()->getType(), CastKind, CurInit.get(), nullptr,
8933 CurInit.get()->getValueKind(), S.CurFPFeatureOverrides());
8934
8935 if (shouldBindAsTemporary(Entity))
8936 // The overall entity is temporary, so this expression should be
8937 // destroyed at the end of its full-expression.
8938 CurInit = S.MaybeBindToTemporary(CurInit.getAs<Expr>());
8939 else if (CreatedObject && shouldDestroyEntity(Entity)) {
8940 // The object outlasts the full-expression, but we need to prepare for
8941 // a destructor being run on it.
8942 // FIXME: It makes no sense to do this here. This should happen
8943 // regardless of how we initialized the entity.
8944 QualType T = CurInit.get()->getType();
8945 if (const RecordType *Record = T->getAs<RecordType>()) {
8946 CXXDestructorDecl *Destructor
8947 = S.LookupDestructor(cast<CXXRecordDecl>(Record->getDecl()));
8948 S.CheckDestructorAccess(CurInit.get()->getBeginLoc(), Destructor,
8949 S.PDiag(diag::err_access_dtor_temp) << T);
8950 S.MarkFunctionReferenced(CurInit.get()->getBeginLoc(), Destructor);
8951 if (S.DiagnoseUseOfDecl(Destructor, CurInit.get()->getBeginLoc()))
8952 return ExprError();
8953 }
8954 }
8955 break;
8956 }
8957
8958 case SK_QualificationConversionLValue:
8959 case SK_QualificationConversionXValue:
8960 case SK_QualificationConversionPRValue: {
8961 // Perform a qualification conversion; these can never go wrong.
8962 ExprValueKind VK =
8963 Step->Kind == SK_QualificationConversionLValue
8964 ? VK_LValue
8965 : (Step->Kind == SK_QualificationConversionXValue ? VK_XValue
8966 : VK_PRValue);
8967 CurInit = S.PerformQualificationConversion(CurInit.get(), Step->Type, VK);
8968 break;
8969 }
8970
8971 case SK_FunctionReferenceConversion:
8972 assert(CurInit.get()->isLValue() &&
8973 "function reference should be lvalue");
8974 CurInit =
8975 S.ImpCastExprToType(CurInit.get(), Step->Type, CK_NoOp, VK_LValue);
8976 break;
8977
8978 case SK_AtomicConversion: {
8979 assert(CurInit.get()->isPRValue() && "cannot convert glvalue to atomic");
8980 CurInit = S.ImpCastExprToType(CurInit.get(), Step->Type,
8981 CK_NonAtomicToAtomic, VK_PRValue);
8982 break;
8983 }
8984
8985 case SK_ConversionSequence:
8986 case SK_ConversionSequenceNoNarrowing: {
8987 if (const auto *FromPtrType =
8988 CurInit.get()->getType()->getAs<PointerType>()) {
8989 if (const auto *ToPtrType = Step->Type->getAs<PointerType>()) {
8990 if (FromPtrType->getPointeeType()->hasAttr(attr::NoDeref) &&
8991 !ToPtrType->getPointeeType()->hasAttr(attr::NoDeref)) {
8992 // Do not check static casts here because they are checked earlier
8993 // in Sema::ActOnCXXNamedCast()
8994 if (!Kind.isStaticCast()) {
8995 S.Diag(CurInit.get()->getExprLoc(),
8996 diag::warn_noderef_to_dereferenceable_pointer)
8997 << CurInit.get()->getSourceRange();
8998 }
8999 }
9000 }
9001 }
9002
9003 Sema::CheckedConversionKind CCK
9004 = Kind.isCStyleCast()? Sema::CCK_CStyleCast
9005 : Kind.isFunctionalCast()? Sema::CCK_FunctionalCast
9006 : Kind.isExplicitCast()? Sema::CCK_OtherCast
9007 : Sema::CCK_ImplicitConversion;
9008 ExprResult CurInitExprRes =
9009 S.PerformImplicitConversion(CurInit.get(), Step->Type, *Step->ICS,
9010 getAssignmentAction(Entity), CCK);
9011 if (CurInitExprRes.isInvalid())
9012 return ExprError();
9013
9014 S.DiscardMisalignedMemberAddress(Step->Type.getTypePtr(), CurInit.get());
9015
9016 CurInit = CurInitExprRes;
9017
9018 if (Step->Kind == SK_ConversionSequenceNoNarrowing &&
9019 S.getLangOpts().CPlusPlus)
9020 DiagnoseNarrowingInInitList(S, *Step->ICS, SourceType, Entity.getType(),
9021 CurInit.get());
9022
9023 break;
9024 }
9025
9026 case SK_ListInitialization: {
9027 if (checkAbstractType(Step->Type))
9028 return ExprError();
9029
9030 InitListExpr *InitList = cast<InitListExpr>(CurInit.get());
9031 // If we're not initializing the top-level entity, we need to create an
9032 // InitializeTemporary entity for our target type.
9033 QualType Ty = Step->Type;
9034 bool IsTemporary = !S.Context.hasSameType(Entity.getType(), Ty);
9035 InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(Ty);
9036 InitializedEntity InitEntity = IsTemporary ? TempEntity : Entity;
9037 InitListChecker PerformInitList(S, InitEntity,
9038 InitList, Ty, /*VerifyOnly=*/false,
9039 /*TreatUnavailableAsInvalid=*/false);
9040 if (PerformInitList.HadError())
9041 return ExprError();
9042
9043 // Hack: We must update *ResultType if available in order to set the
9044 // bounds of arrays, e.g. in 'int ar[] = {1, 2, 3};'.
9045 // Worst case: 'const int (&arref)[] = {1, 2, 3};'.
9046 if (ResultType &&
9047 ResultType->getNonReferenceType()->isIncompleteArrayType()) {
9048 if ((*ResultType)->isRValueReferenceType())
9049 Ty = S.Context.getRValueReferenceType(Ty);
9050 else if ((*ResultType)->isLValueReferenceType())
9051 Ty = S.Context.getLValueReferenceType(Ty,
9052 (*ResultType)->castAs<LValueReferenceType>()->isSpelledAsLValue());
9053 *ResultType = Ty;
9054 }
9055
9056 InitListExpr *StructuredInitList =
9057 PerformInitList.getFullyStructuredList();
9058 CurInit.get();
9059 CurInit = shouldBindAsTemporary(InitEntity)
9060 ? S.MaybeBindToTemporary(StructuredInitList)
9061 : StructuredInitList;
9062 break;
9063 }
9064
9065 case SK_ConstructorInitializationFromList: {
9066 if (checkAbstractType(Step->Type))
9067 return ExprError();
9068
9069 // When an initializer list is passed for a parameter of type "reference
9070 // to object", we don't get an EK_Temporary entity, but instead an
9071 // EK_Parameter entity with reference type.
9072 // FIXME: This is a hack. What we really should do is create a user
9073 // conversion step for this case, but this makes it considerably more
9074 // complicated. For now, this will do.
9075 InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(
9076 Entity.getType().getNonReferenceType());
9077 bool UseTemporary = Entity.getType()->isReferenceType();
9078 assert(Args.size() == 1 && "expected a single argument for list init");
9079 InitListExpr *InitList = cast<InitListExpr>(Args[0]);
9080 S.Diag(InitList->getExprLoc(), diag::warn_cxx98_compat_ctor_list_init)
9081 << InitList->getSourceRange();
9082 MultiExprArg Arg(InitList->getInits(), InitList->getNumInits());
9083 CurInit = PerformConstructorInitialization(S, UseTemporary ? TempEntity :
9084 Entity,
9085 Kind, Arg, *Step,
9086 ConstructorInitRequiresZeroInit,
9087 /*IsListInitialization*/true,
9088 /*IsStdInitListInit*/false,
9089 InitList->getLBraceLoc(),
9090 InitList->getRBraceLoc());
9091 break;
9092 }
9093
9094 case SK_UnwrapInitList:
9095 CurInit = cast<InitListExpr>(CurInit.get())->getInit(0);
9096 break;
9097
9098 case SK_RewrapInitList: {
9099 Expr *E = CurInit.get();
9100 InitListExpr *Syntactic = Step->WrappingSyntacticList;
9101 InitListExpr *ILE = new (S.Context) InitListExpr(S.Context,
9102 Syntactic->getLBraceLoc(), E, Syntactic->getRBraceLoc());
9103 ILE->setSyntacticForm(Syntactic);
9104 ILE->setType(E->getType());
9105 ILE->setValueKind(E->getValueKind());
9106 CurInit = ILE;
9107 break;
9108 }
9109
9110 case SK_ConstructorInitialization:
9111 case SK_StdInitializerListConstructorCall: {
9112 if (checkAbstractType(Step->Type))
9113 return ExprError();
9114
9115 // When an initializer list is passed for a parameter of type "reference
9116 // to object", we don't get an EK_Temporary entity, but instead an
9117 // EK_Parameter entity with reference type.
9118 // FIXME: This is a hack. What we really should do is create a user
9119 // conversion step for this case, but this makes it considerably more
9120 // complicated. For now, this will do.
9121 InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(
9122 Entity.getType().getNonReferenceType());
9123 bool UseTemporary = Entity.getType()->isReferenceType();
9124 bool IsStdInitListInit =
9125 Step->Kind == SK_StdInitializerListConstructorCall;
9126 Expr *Source = CurInit.get();
9127 SourceRange Range = Kind.hasParenOrBraceRange()
9128 ? Kind.getParenOrBraceRange()
9129 : SourceRange();
9130 CurInit = PerformConstructorInitialization(
9131 S, UseTemporary ? TempEntity : Entity, Kind,
9132 Source ? MultiExprArg(Source) : Args, *Step,
9133 ConstructorInitRequiresZeroInit,
9134 /*IsListInitialization*/ IsStdInitListInit,
9135 /*IsStdInitListInitialization*/ IsStdInitListInit,
9136 /*LBraceLoc*/ Range.getBegin(),
9137 /*RBraceLoc*/ Range.getEnd());
9138 break;
9139 }
9140
9141 case SK_ZeroInitialization: {
9142 step_iterator NextStep = Step;
9143 ++NextStep;
9144 if (NextStep != StepEnd &&
9145 (NextStep->Kind == SK_ConstructorInitialization ||
9146 NextStep->Kind == SK_ConstructorInitializationFromList)) {
9147 // The need for zero-initialization is recorded directly into
9148 // the call to the object's constructor within the next step.
9149 ConstructorInitRequiresZeroInit = true;
9150 } else if (Kind.getKind() == InitializationKind::IK_Value &&
9151 S.getLangOpts().CPlusPlus &&
9152 !Kind.isImplicitValueInit()) {
9153 TypeSourceInfo *TSInfo = Entity.getTypeSourceInfo();
9154 if (!TSInfo)
9155 TSInfo = S.Context.getTrivialTypeSourceInfo(Step->Type,
9156 Kind.getRange().getBegin());
9157
9158 CurInit = new (S.Context) CXXScalarValueInitExpr(
9159 Entity.getType().getNonLValueExprType(S.Context), TSInfo,
9160 Kind.getRange().getEnd());
9161 } else {
9162 CurInit = new (S.Context) ImplicitValueInitExpr(Step->Type);
9163 }
9164 break;
9165 }
9166
9167 case SK_CAssignment: {
9168 QualType SourceType = CurInit.get()->getType();
9169
9170 // Save off the initial CurInit in case we need to emit a diagnostic
9171 ExprResult InitialCurInit = CurInit;
9172 ExprResult Result = CurInit;
9173 Sema::AssignConvertType ConvTy =
9174 S.CheckSingleAssignmentConstraints(Step->Type, Result, true,
9175 Entity.getKind() == InitializedEntity::EK_Parameter_CF_Audited);
9176 if (Result.isInvalid())
9177 return ExprError();
9178 CurInit = Result;
9179
9180 // If this is a call, allow conversion to a transparent union.
9181 ExprResult CurInitExprRes = CurInit;
9182 if (ConvTy != Sema::Compatible &&
9183 Entity.isParameterKind() &&
9184 S.CheckTransparentUnionArgumentConstraints(Step->Type, CurInitExprRes)
9185 == Sema::Compatible)
9186 ConvTy = Sema::Compatible;
9187 if (CurInitExprRes.isInvalid())
9188 return ExprError();
9189 CurInit = CurInitExprRes;
9190
9191 bool Complained;
9192 if (S.DiagnoseAssignmentResult(ConvTy, Kind.getLocation(),
9193 Step->Type, SourceType,
9194 InitialCurInit.get(),
9195 getAssignmentAction(Entity, true),
9196 &Complained)) {
9197 PrintInitLocationNote(S, Entity);
9198 return ExprError();
9199 } else if (Complained)
9200 PrintInitLocationNote(S, Entity);
9201 break;
9202 }
9203
9204 case SK_StringInit: {
9205 QualType Ty = Step->Type;
9206 bool UpdateType = ResultType && Entity.getType()->isIncompleteArrayType();
9207 CheckStringInit(CurInit.get(), UpdateType ? *ResultType : Ty,
9208 S.Context.getAsArrayType(Ty), S);
9209 break;
9210 }
9211
9212 case SK_ObjCObjectConversion:
9213 CurInit = S.ImpCastExprToType(CurInit.get(), Step->Type,
9214 CK_ObjCObjectLValueCast,
9215 CurInit.get()->getValueKind());
9216 break;
9217
9218 case SK_ArrayLoopIndex: {
9219 Expr *Cur = CurInit.get();
9220 Expr *BaseExpr = new (S.Context)
9221 OpaqueValueExpr(Cur->getExprLoc(), Cur->getType(),
9222 Cur->getValueKind(), Cur->getObjectKind(), Cur);
9223 Expr *IndexExpr =
9224 new (S.Context) ArrayInitIndexExpr(S.Context.getSizeType());
9225 CurInit = S.CreateBuiltinArraySubscriptExpr(
9226 BaseExpr, Kind.getLocation(), IndexExpr, Kind.getLocation());
9227 ArrayLoopCommonExprs.push_back(BaseExpr);
9228 break;
9229 }
9230
9231 case SK_ArrayLoopInit: {
9232 assert(!ArrayLoopCommonExprs.empty() &&
9233 "mismatched SK_ArrayLoopIndex and SK_ArrayLoopInit");
9234 Expr *Common = ArrayLoopCommonExprs.pop_back_val();
9235 CurInit = new (S.Context) ArrayInitLoopExpr(Step->Type, Common,
9236 CurInit.get());
9237 break;
9238 }
9239
9240 case SK_GNUArrayInit:
9241 // Okay: we checked everything before creating this step. Note that
9242 // this is a GNU extension.
9243 S.Diag(Kind.getLocation(), diag::ext_array_init_copy)
9244 << Step->Type << CurInit.get()->getType()
9245 << CurInit.get()->getSourceRange();
9246 updateGNUCompoundLiteralRValue(CurInit.get());
9247 [[fallthrough]];
9248 case SK_ArrayInit:
9249 // If the destination type is an incomplete array type, update the
9250 // type accordingly.
9251 if (ResultType) {
9252 if (const IncompleteArrayType *IncompleteDest
9253 = S.Context.getAsIncompleteArrayType(Step->Type)) {
9254 if (const ConstantArrayType *ConstantSource
9255 = S.Context.getAsConstantArrayType(CurInit.get()->getType())) {
9256 *ResultType = S.Context.getConstantArrayType(
9257 IncompleteDest->getElementType(), ConstantSource->getSize(),
9258 ConstantSource->getSizeExpr(), ArraySizeModifier::Normal, 0);
9259 }
9260 }
9261 }
9262 break;
9263
9264 case SK_ParenthesizedArrayInit:
9265 // Okay: we checked everything before creating this step. Note that
9266 // this is a GNU extension.
9267 S.Diag(Kind.getLocation(), diag::ext_array_init_parens)
9268 << CurInit.get()->getSourceRange();
9269 break;
9270
9271 case SK_PassByIndirectCopyRestore:
9272 case SK_PassByIndirectRestore:
9273 checkIndirectCopyRestoreSource(S, CurInit.get());
9274 CurInit = new (S.Context) ObjCIndirectCopyRestoreExpr(
9275 CurInit.get(), Step->Type,
9276 Step->Kind == SK_PassByIndirectCopyRestore);
9277 break;
9278
9279 case SK_ProduceObjCObject:
9280 CurInit = ImplicitCastExpr::Create(
9281 S.Context, Step->Type, CK_ARCProduceObject, CurInit.get(), nullptr,
9282 VK_PRValue, FPOptionsOverride());
9283 break;
9284
9285 case SK_StdInitializerList: {
9286 S.Diag(CurInit.get()->getExprLoc(),
9287 diag::warn_cxx98_compat_initializer_list_init)
9288 << CurInit.get()->getSourceRange();
9289
9290 // Materialize the temporary into memory.
9291 MaterializeTemporaryExpr *MTE = S.CreateMaterializeTemporaryExpr(
9292 CurInit.get()->getType(), CurInit.get(),
9293 /*BoundToLvalueReference=*/false);
9294
9295 // Wrap it in a construction of a std::initializer_list<T>.
9296 CurInit = new (S.Context) CXXStdInitializerListExpr(Step->Type, MTE);
9297
9298 // Bind the result, in case the library has given initializer_list a
9299 // non-trivial destructor.
9300 if (shouldBindAsTemporary(Entity))
9301 CurInit = S.MaybeBindToTemporary(CurInit.get());
9302 break;
9303 }
9304
9305 case SK_OCLSamplerInit: {
9306 // Sampler initialization have 5 cases:
9307 // 1. function argument passing
9308 // 1a. argument is a file-scope variable
9309 // 1b. argument is a function-scope variable
9310 // 1c. argument is one of caller function's parameters
9311 // 2. variable initialization
9312 // 2a. initializing a file-scope variable
9313 // 2b. initializing a function-scope variable
9314 //
9315 // For file-scope variables, since they cannot be initialized by function
9316 // call of __translate_sampler_initializer in LLVM IR, their references
9317 // need to be replaced by a cast from their literal initializers to
9318 // sampler type. Since sampler variables can only be used in function
9319 // calls as arguments, we only need to replace them when handling the
9320 // argument passing.
9321 assert(Step->Type->isSamplerT() &&
9322 "Sampler initialization on non-sampler type.");
9323 Expr *Init = CurInit.get()->IgnoreParens();
9324 QualType SourceType = Init->getType();
9325 // Case 1
9326 if (Entity.isParameterKind()) {
9327 if (!SourceType->isSamplerT() && !SourceType->isIntegerType()) {
9328 S.Diag(Kind.getLocation(), diag::err_sampler_argument_required)
9329 << SourceType;
9330 break;
9331 } else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Init)) {
9332 auto Var = cast<VarDecl>(DRE->getDecl());
9333 // Case 1b and 1c
9334 // No cast from integer to sampler is needed.
9335 if (!Var->hasGlobalStorage()) {
9336 CurInit = ImplicitCastExpr::Create(
9337 S.Context, Step->Type, CK_LValueToRValue, Init,
9338 /*BasePath=*/nullptr, VK_PRValue, FPOptionsOverride());
9339 break;
9340 }
9341 // Case 1a
9342 // For function call with a file-scope sampler variable as argument,
9343 // get the integer literal.
9344 // Do not diagnose if the file-scope variable does not have initializer
9345 // since this has already been diagnosed when parsing the variable
9346 // declaration.
9347 if (!Var->getInit() || !isa<ImplicitCastExpr>(Var->getInit()))
9348 break;
9349 Init = cast<ImplicitCastExpr>(const_cast<Expr*>(
9350 Var->getInit()))->getSubExpr();
9351 SourceType = Init->getType();
9352 }
9353 } else {
9354 // Case 2
9355 // Check initializer is 32 bit integer constant.
9356 // If the initializer is taken from global variable, do not diagnose since
9357 // this has already been done when parsing the variable declaration.
9358 if (!Init->isConstantInitializer(S.Context, false))
9359 break;
9360
9361 if (!SourceType->isIntegerType() ||
9362 32 != S.Context.getIntWidth(SourceType)) {
9363 S.Diag(Kind.getLocation(), diag::err_sampler_initializer_not_integer)
9364 << SourceType;
9365 break;
9366 }
9367
9368 Expr::EvalResult EVResult;
9369 Init->EvaluateAsInt(EVResult, S.Context);
9370 llvm::APSInt Result = EVResult.Val.getInt();
9371 const uint64_t SamplerValue = Result.getLimitedValue();
9372 // 32-bit value of sampler's initializer is interpreted as
9373 // bit-field with the following structure:
9374 // |unspecified|Filter|Addressing Mode| Normalized Coords|
9375 // |31 6|5 4|3 1| 0|
9376 // This structure corresponds to enum values of sampler properties
9377 // defined in SPIR spec v1.2 and also opencl-c.h
9378 unsigned AddressingMode = (0x0E & SamplerValue) >> 1;
9379 unsigned FilterMode = (0x30 & SamplerValue) >> 4;
9380 if (FilterMode != 1 && FilterMode != 2 &&
9381 !S.getOpenCLOptions().isAvailableOption(
9382 "cl_intel_device_side_avc_motion_estimation", S.getLangOpts()))
9383 S.Diag(Kind.getLocation(),
9384 diag::warn_sampler_initializer_invalid_bits)
9385 << "Filter Mode";
9386 if (AddressingMode > 4)
9387 S.Diag(Kind.getLocation(),
9388 diag::warn_sampler_initializer_invalid_bits)
9389 << "Addressing Mode";
9390 }
9391
9392 // Cases 1a, 2a and 2b
9393 // Insert cast from integer to sampler.
9394 CurInit = S.ImpCastExprToType(Init, S.Context.OCLSamplerTy,
9395 CK_IntToOCLSampler);
9396 break;
9397 }
9398 case SK_OCLZeroOpaqueType: {
9399 assert((Step->Type->isEventT() || Step->Type->isQueueT() ||
9400 Step->Type->isOCLIntelSubgroupAVCType()) &&
9401 "Wrong type for initialization of OpenCL opaque type.");
9402
9403 CurInit = S.ImpCastExprToType(CurInit.get(), Step->Type,
9404 CK_ZeroToOCLOpaqueType,
9405 CurInit.get()->getValueKind());
9406 break;
9407 }
9408 case SK_ParenthesizedListInit: {
9409 CurInit = nullptr;
9410 TryOrBuildParenListInitialization(S, Entity, Kind, Args, *this,
9411 /*VerifyOnly=*/false, &CurInit);
9412 if (CurInit.get() && ResultType)
9413 *ResultType = CurInit.get()->getType();
9414 if (shouldBindAsTemporary(Entity))
9415 CurInit = S.MaybeBindToTemporary(CurInit.get());
9416 break;
9417 }
9418 }
9419 }
9420
9421 Expr *Init = CurInit.get();
9422 if (!Init)
9423 return ExprError();
9424
9425 // Check whether the initializer has a shorter lifetime than the initialized
9426 // entity, and if not, either lifetime-extend or warn as appropriate.
9427 S.checkInitializerLifetime(Entity, Init);
9428
9429 // Diagnose non-fatal problems with the completed initialization.
9430 if (InitializedEntity::EntityKind EK = Entity.getKind();
9431 (EK == InitializedEntity::EK_Member ||
9432 EK == InitializedEntity::EK_ParenAggInitMember) &&
9433 cast<FieldDecl>(Entity.getDecl())->isBitField())
9434 S.CheckBitFieldInitialization(Kind.getLocation(),
9435 cast<FieldDecl>(Entity.getDecl()), Init);
9436
9437 // Check for std::move on construction.
9438 CheckMoveOnConstruction(S, Init,
9439 Entity.getKind() == InitializedEntity::EK_Result);
9440
9441 return Init;
9442 }
9443
9444 /// Somewhere within T there is an uninitialized reference subobject.
9445 /// Dig it out and diagnose it.
DiagnoseUninitializedReference(Sema & S,SourceLocation Loc,QualType T)9446 static bool DiagnoseUninitializedReference(Sema &S, SourceLocation Loc,
9447 QualType T) {
9448 if (T->isReferenceType()) {
9449 S.Diag(Loc, diag::err_reference_without_init)
9450 << T.getNonReferenceType();
9451 return true;
9452 }
9453
9454 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
9455 if (!RD || !RD->hasUninitializedReferenceMember())
9456 return false;
9457
9458 for (const auto *FI : RD->fields()) {
9459 if (FI->isUnnamedBitfield())
9460 continue;
9461
9462 if (DiagnoseUninitializedReference(S, FI->getLocation(), FI->getType())) {
9463 S.Diag(Loc, diag::note_value_initialization_here) << RD;
9464 return true;
9465 }
9466 }
9467
9468 for (const auto &BI : RD->bases()) {
9469 if (DiagnoseUninitializedReference(S, BI.getBeginLoc(), BI.getType())) {
9470 S.Diag(Loc, diag::note_value_initialization_here) << RD;
9471 return true;
9472 }
9473 }
9474
9475 return false;
9476 }
9477
9478
9479 //===----------------------------------------------------------------------===//
9480 // Diagnose initialization failures
9481 //===----------------------------------------------------------------------===//
9482
9483 /// Emit notes associated with an initialization that failed due to a
9484 /// "simple" conversion failure.
emitBadConversionNotes(Sema & S,const InitializedEntity & entity,Expr * op)9485 static void emitBadConversionNotes(Sema &S, const InitializedEntity &entity,
9486 Expr *op) {
9487 QualType destType = entity.getType();
9488 if (destType.getNonReferenceType()->isObjCObjectPointerType() &&
9489 op->getType()->isObjCObjectPointerType()) {
9490
9491 // Emit a possible note about the conversion failing because the
9492 // operand is a message send with a related result type.
9493 S.EmitRelatedResultTypeNote(op);
9494
9495 // Emit a possible note about a return failing because we're
9496 // expecting a related result type.
9497 if (entity.getKind() == InitializedEntity::EK_Result)
9498 S.EmitRelatedResultTypeNoteForReturn(destType);
9499 }
9500 QualType fromType = op->getType();
9501 QualType fromPointeeType = fromType.getCanonicalType()->getPointeeType();
9502 QualType destPointeeType = destType.getCanonicalType()->getPointeeType();
9503 auto *fromDecl = fromType->getPointeeCXXRecordDecl();
9504 auto *destDecl = destType->getPointeeCXXRecordDecl();
9505 if (fromDecl && destDecl && fromDecl->getDeclKind() == Decl::CXXRecord &&
9506 destDecl->getDeclKind() == Decl::CXXRecord &&
9507 !fromDecl->isInvalidDecl() && !destDecl->isInvalidDecl() &&
9508 !fromDecl->hasDefinition() &&
9509 destPointeeType.getQualifiers().compatiblyIncludes(
9510 fromPointeeType.getQualifiers()))
9511 S.Diag(fromDecl->getLocation(), diag::note_forward_class_conversion)
9512 << S.getASTContext().getTagDeclType(fromDecl)
9513 << S.getASTContext().getTagDeclType(destDecl);
9514 }
9515
diagnoseListInit(Sema & S,const InitializedEntity & Entity,InitListExpr * InitList)9516 static void diagnoseListInit(Sema &S, const InitializedEntity &Entity,
9517 InitListExpr *InitList) {
9518 QualType DestType = Entity.getType();
9519
9520 QualType E;
9521 if (S.getLangOpts().CPlusPlus11 && S.isStdInitializerList(DestType, &E)) {
9522 QualType ArrayType = S.Context.getConstantArrayType(
9523 E.withConst(),
9524 llvm::APInt(S.Context.getTypeSize(S.Context.getSizeType()),
9525 InitList->getNumInits()),
9526 nullptr, clang::ArraySizeModifier::Normal, 0);
9527 InitializedEntity HiddenArray =
9528 InitializedEntity::InitializeTemporary(ArrayType);
9529 return diagnoseListInit(S, HiddenArray, InitList);
9530 }
9531
9532 if (DestType->isReferenceType()) {
9533 // A list-initialization failure for a reference means that we tried to
9534 // create a temporary of the inner type (per [dcl.init.list]p3.6) and the
9535 // inner initialization failed.
9536 QualType T = DestType->castAs<ReferenceType>()->getPointeeType();
9537 diagnoseListInit(S, InitializedEntity::InitializeTemporary(T), InitList);
9538 SourceLocation Loc = InitList->getBeginLoc();
9539 if (auto *D = Entity.getDecl())
9540 Loc = D->getLocation();
9541 S.Diag(Loc, diag::note_in_reference_temporary_list_initializer) << T;
9542 return;
9543 }
9544
9545 InitListChecker DiagnoseInitList(S, Entity, InitList, DestType,
9546 /*VerifyOnly=*/false,
9547 /*TreatUnavailableAsInvalid=*/false);
9548 assert(DiagnoseInitList.HadError() &&
9549 "Inconsistent init list check result.");
9550 }
9551
Diagnose(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,ArrayRef<Expr * > Args)9552 bool InitializationSequence::Diagnose(Sema &S,
9553 const InitializedEntity &Entity,
9554 const InitializationKind &Kind,
9555 ArrayRef<Expr *> Args) {
9556 if (!Failed())
9557 return false;
9558
9559 // When we want to diagnose only one element of a braced-init-list,
9560 // we need to factor it out.
9561 Expr *OnlyArg;
9562 if (Args.size() == 1) {
9563 auto *List = dyn_cast<InitListExpr>(Args[0]);
9564 if (List && List->getNumInits() == 1)
9565 OnlyArg = List->getInit(0);
9566 else
9567 OnlyArg = Args[0];
9568 }
9569 else
9570 OnlyArg = nullptr;
9571
9572 QualType DestType = Entity.getType();
9573 switch (Failure) {
9574 case FK_TooManyInitsForReference:
9575 // FIXME: Customize for the initialized entity?
9576 if (Args.empty()) {
9577 // Dig out the reference subobject which is uninitialized and diagnose it.
9578 // If this is value-initialization, this could be nested some way within
9579 // the target type.
9580 assert(Kind.getKind() == InitializationKind::IK_Value ||
9581 DestType->isReferenceType());
9582 bool Diagnosed =
9583 DiagnoseUninitializedReference(S, Kind.getLocation(), DestType);
9584 assert(Diagnosed && "couldn't find uninitialized reference to diagnose");
9585 (void)Diagnosed;
9586 } else // FIXME: diagnostic below could be better!
9587 S.Diag(Kind.getLocation(), diag::err_reference_has_multiple_inits)
9588 << SourceRange(Args.front()->getBeginLoc(), Args.back()->getEndLoc());
9589 break;
9590 case FK_ParenthesizedListInitForReference:
9591 S.Diag(Kind.getLocation(), diag::err_list_init_in_parens)
9592 << 1 << Entity.getType() << Args[0]->getSourceRange();
9593 break;
9594
9595 case FK_ArrayNeedsInitList:
9596 S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 0;
9597 break;
9598 case FK_ArrayNeedsInitListOrStringLiteral:
9599 S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 1;
9600 break;
9601 case FK_ArrayNeedsInitListOrWideStringLiteral:
9602 S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 2;
9603 break;
9604 case FK_NarrowStringIntoWideCharArray:
9605 S.Diag(Kind.getLocation(), diag::err_array_init_narrow_string_into_wchar);
9606 break;
9607 case FK_WideStringIntoCharArray:
9608 S.Diag(Kind.getLocation(), diag::err_array_init_wide_string_into_char);
9609 break;
9610 case FK_IncompatWideStringIntoWideChar:
9611 S.Diag(Kind.getLocation(),
9612 diag::err_array_init_incompat_wide_string_into_wchar);
9613 break;
9614 case FK_PlainStringIntoUTF8Char:
9615 S.Diag(Kind.getLocation(),
9616 diag::err_array_init_plain_string_into_char8_t);
9617 S.Diag(Args.front()->getBeginLoc(),
9618 diag::note_array_init_plain_string_into_char8_t)
9619 << FixItHint::CreateInsertion(Args.front()->getBeginLoc(), "u8");
9620 break;
9621 case FK_UTF8StringIntoPlainChar:
9622 S.Diag(Kind.getLocation(), diag::err_array_init_utf8_string_into_char)
9623 << DestType->isSignedIntegerType() << S.getLangOpts().CPlusPlus20;
9624 break;
9625 case FK_ArrayTypeMismatch:
9626 case FK_NonConstantArrayInit:
9627 S.Diag(Kind.getLocation(),
9628 (Failure == FK_ArrayTypeMismatch
9629 ? diag::err_array_init_different_type
9630 : diag::err_array_init_non_constant_array))
9631 << DestType.getNonReferenceType()
9632 << OnlyArg->getType()
9633 << Args[0]->getSourceRange();
9634 break;
9635
9636 case FK_VariableLengthArrayHasInitializer:
9637 S.Diag(Kind.getLocation(), diag::err_variable_object_no_init)
9638 << Args[0]->getSourceRange();
9639 break;
9640
9641 case FK_AddressOfOverloadFailed: {
9642 DeclAccessPair Found;
9643 S.ResolveAddressOfOverloadedFunction(OnlyArg,
9644 DestType.getNonReferenceType(),
9645 true,
9646 Found);
9647 break;
9648 }
9649
9650 case FK_AddressOfUnaddressableFunction: {
9651 auto *FD = cast<FunctionDecl>(cast<DeclRefExpr>(OnlyArg)->getDecl());
9652 S.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true,
9653 OnlyArg->getBeginLoc());
9654 break;
9655 }
9656
9657 case FK_ReferenceInitOverloadFailed:
9658 case FK_UserConversionOverloadFailed:
9659 switch (FailedOverloadResult) {
9660 case OR_Ambiguous:
9661
9662 FailedCandidateSet.NoteCandidates(
9663 PartialDiagnosticAt(
9664 Kind.getLocation(),
9665 Failure == FK_UserConversionOverloadFailed
9666 ? (S.PDiag(diag::err_typecheck_ambiguous_condition)
9667 << OnlyArg->getType() << DestType
9668 << Args[0]->getSourceRange())
9669 : (S.PDiag(diag::err_ref_init_ambiguous)
9670 << DestType << OnlyArg->getType()
9671 << Args[0]->getSourceRange())),
9672 S, OCD_AmbiguousCandidates, Args);
9673 break;
9674
9675 case OR_No_Viable_Function: {
9676 auto Cands = FailedCandidateSet.CompleteCandidates(S, OCD_AllCandidates, Args);
9677 if (!S.RequireCompleteType(Kind.getLocation(),
9678 DestType.getNonReferenceType(),
9679 diag::err_typecheck_nonviable_condition_incomplete,
9680 OnlyArg->getType(), Args[0]->getSourceRange()))
9681 S.Diag(Kind.getLocation(), diag::err_typecheck_nonviable_condition)
9682 << (Entity.getKind() == InitializedEntity::EK_Result)
9683 << OnlyArg->getType() << Args[0]->getSourceRange()
9684 << DestType.getNonReferenceType();
9685
9686 FailedCandidateSet.NoteCandidates(S, Args, Cands);
9687 break;
9688 }
9689 case OR_Deleted: {
9690 S.Diag(Kind.getLocation(), diag::err_typecheck_deleted_function)
9691 << OnlyArg->getType() << DestType.getNonReferenceType()
9692 << Args[0]->getSourceRange();
9693 OverloadCandidateSet::iterator Best;
9694 OverloadingResult Ovl
9695 = FailedCandidateSet.BestViableFunction(S, Kind.getLocation(), Best);
9696 if (Ovl == OR_Deleted) {
9697 S.NoteDeletedFunction(Best->Function);
9698 } else {
9699 llvm_unreachable("Inconsistent overload resolution?");
9700 }
9701 break;
9702 }
9703
9704 case OR_Success:
9705 llvm_unreachable("Conversion did not fail!");
9706 }
9707 break;
9708
9709 case FK_NonConstLValueReferenceBindingToTemporary:
9710 if (isa<InitListExpr>(Args[0])) {
9711 S.Diag(Kind.getLocation(),
9712 diag::err_lvalue_reference_bind_to_initlist)
9713 << DestType.getNonReferenceType().isVolatileQualified()
9714 << DestType.getNonReferenceType()
9715 << Args[0]->getSourceRange();
9716 break;
9717 }
9718 [[fallthrough]];
9719
9720 case FK_NonConstLValueReferenceBindingToUnrelated:
9721 S.Diag(Kind.getLocation(),
9722 Failure == FK_NonConstLValueReferenceBindingToTemporary
9723 ? diag::err_lvalue_reference_bind_to_temporary
9724 : diag::err_lvalue_reference_bind_to_unrelated)
9725 << DestType.getNonReferenceType().isVolatileQualified()
9726 << DestType.getNonReferenceType()
9727 << OnlyArg->getType()
9728 << Args[0]->getSourceRange();
9729 break;
9730
9731 case FK_NonConstLValueReferenceBindingToBitfield: {
9732 // We don't necessarily have an unambiguous source bit-field.
9733 FieldDecl *BitField = Args[0]->getSourceBitField();
9734 S.Diag(Kind.getLocation(), diag::err_reference_bind_to_bitfield)
9735 << DestType.isVolatileQualified()
9736 << (BitField ? BitField->getDeclName() : DeclarationName())
9737 << (BitField != nullptr)
9738 << Args[0]->getSourceRange();
9739 if (BitField)
9740 S.Diag(BitField->getLocation(), diag::note_bitfield_decl);
9741 break;
9742 }
9743
9744 case FK_NonConstLValueReferenceBindingToVectorElement:
9745 S.Diag(Kind.getLocation(), diag::err_reference_bind_to_vector_element)
9746 << DestType.isVolatileQualified()
9747 << Args[0]->getSourceRange();
9748 break;
9749
9750 case FK_NonConstLValueReferenceBindingToMatrixElement:
9751 S.Diag(Kind.getLocation(), diag::err_reference_bind_to_matrix_element)
9752 << DestType.isVolatileQualified() << Args[0]->getSourceRange();
9753 break;
9754
9755 case FK_RValueReferenceBindingToLValue:
9756 S.Diag(Kind.getLocation(), diag::err_lvalue_to_rvalue_ref)
9757 << DestType.getNonReferenceType() << OnlyArg->getType()
9758 << Args[0]->getSourceRange();
9759 break;
9760
9761 case FK_ReferenceAddrspaceMismatchTemporary:
9762 S.Diag(Kind.getLocation(), diag::err_reference_bind_temporary_addrspace)
9763 << DestType << Args[0]->getSourceRange();
9764 break;
9765
9766 case FK_ReferenceInitDropsQualifiers: {
9767 QualType SourceType = OnlyArg->getType();
9768 QualType NonRefType = DestType.getNonReferenceType();
9769 Qualifiers DroppedQualifiers =
9770 SourceType.getQualifiers() - NonRefType.getQualifiers();
9771
9772 if (!NonRefType.getQualifiers().isAddressSpaceSupersetOf(
9773 SourceType.getQualifiers()))
9774 S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
9775 << NonRefType << SourceType << 1 /*addr space*/
9776 << Args[0]->getSourceRange();
9777 else if (DroppedQualifiers.hasQualifiers())
9778 S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
9779 << NonRefType << SourceType << 0 /*cv quals*/
9780 << Qualifiers::fromCVRMask(DroppedQualifiers.getCVRQualifiers())
9781 << DroppedQualifiers.getCVRQualifiers() << Args[0]->getSourceRange();
9782 else
9783 // FIXME: Consider decomposing the type and explaining which qualifiers
9784 // were dropped where, or on which level a 'const' is missing, etc.
9785 S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
9786 << NonRefType << SourceType << 2 /*incompatible quals*/
9787 << Args[0]->getSourceRange();
9788 break;
9789 }
9790
9791 case FK_ReferenceInitFailed:
9792 S.Diag(Kind.getLocation(), diag::err_reference_bind_failed)
9793 << DestType.getNonReferenceType()
9794 << DestType.getNonReferenceType()->isIncompleteType()
9795 << OnlyArg->isLValue()
9796 << OnlyArg->getType()
9797 << Args[0]->getSourceRange();
9798 emitBadConversionNotes(S, Entity, Args[0]);
9799 break;
9800
9801 case FK_ConversionFailed: {
9802 QualType FromType = OnlyArg->getType();
9803 PartialDiagnostic PDiag = S.PDiag(diag::err_init_conversion_failed)
9804 << (int)Entity.getKind()
9805 << DestType
9806 << OnlyArg->isLValue()
9807 << FromType
9808 << Args[0]->getSourceRange();
9809 S.HandleFunctionTypeMismatch(PDiag, FromType, DestType);
9810 S.Diag(Kind.getLocation(), PDiag);
9811 emitBadConversionNotes(S, Entity, Args[0]);
9812 break;
9813 }
9814
9815 case FK_ConversionFromPropertyFailed:
9816 // No-op. This error has already been reported.
9817 break;
9818
9819 case FK_TooManyInitsForScalar: {
9820 SourceRange R;
9821
9822 auto *InitList = dyn_cast<InitListExpr>(Args[0]);
9823 if (InitList && InitList->getNumInits() >= 1) {
9824 R = SourceRange(InitList->getInit(0)->getEndLoc(), InitList->getEndLoc());
9825 } else {
9826 assert(Args.size() > 1 && "Expected multiple initializers!");
9827 R = SourceRange(Args.front()->getEndLoc(), Args.back()->getEndLoc());
9828 }
9829
9830 R.setBegin(S.getLocForEndOfToken(R.getBegin()));
9831 if (Kind.isCStyleOrFunctionalCast())
9832 S.Diag(Kind.getLocation(), diag::err_builtin_func_cast_more_than_one_arg)
9833 << R;
9834 else
9835 S.Diag(Kind.getLocation(), diag::err_excess_initializers)
9836 << /*scalar=*/2 << R;
9837 break;
9838 }
9839
9840 case FK_ParenthesizedListInitForScalar:
9841 S.Diag(Kind.getLocation(), diag::err_list_init_in_parens)
9842 << 0 << Entity.getType() << Args[0]->getSourceRange();
9843 break;
9844
9845 case FK_ReferenceBindingToInitList:
9846 S.Diag(Kind.getLocation(), diag::err_reference_bind_init_list)
9847 << DestType.getNonReferenceType() << Args[0]->getSourceRange();
9848 break;
9849
9850 case FK_InitListBadDestinationType:
9851 S.Diag(Kind.getLocation(), diag::err_init_list_bad_dest_type)
9852 << (DestType->isRecordType()) << DestType << Args[0]->getSourceRange();
9853 break;
9854
9855 case FK_ListConstructorOverloadFailed:
9856 case FK_ConstructorOverloadFailed: {
9857 SourceRange ArgsRange;
9858 if (Args.size())
9859 ArgsRange =
9860 SourceRange(Args.front()->getBeginLoc(), Args.back()->getEndLoc());
9861
9862 if (Failure == FK_ListConstructorOverloadFailed) {
9863 assert(Args.size() == 1 &&
9864 "List construction from other than 1 argument.");
9865 InitListExpr *InitList = cast<InitListExpr>(Args[0]);
9866 Args = MultiExprArg(InitList->getInits(), InitList->getNumInits());
9867 }
9868
9869 // FIXME: Using "DestType" for the entity we're printing is probably
9870 // bad.
9871 switch (FailedOverloadResult) {
9872 case OR_Ambiguous:
9873 FailedCandidateSet.NoteCandidates(
9874 PartialDiagnosticAt(Kind.getLocation(),
9875 S.PDiag(diag::err_ovl_ambiguous_init)
9876 << DestType << ArgsRange),
9877 S, OCD_AmbiguousCandidates, Args);
9878 break;
9879
9880 case OR_No_Viable_Function:
9881 if (Kind.getKind() == InitializationKind::IK_Default &&
9882 (Entity.getKind() == InitializedEntity::EK_Base ||
9883 Entity.getKind() == InitializedEntity::EK_Member ||
9884 Entity.getKind() == InitializedEntity::EK_ParenAggInitMember) &&
9885 isa<CXXConstructorDecl>(S.CurContext)) {
9886 // This is implicit default initialization of a member or
9887 // base within a constructor. If no viable function was
9888 // found, notify the user that they need to explicitly
9889 // initialize this base/member.
9890 CXXConstructorDecl *Constructor
9891 = cast<CXXConstructorDecl>(S.CurContext);
9892 const CXXRecordDecl *InheritedFrom = nullptr;
9893 if (auto Inherited = Constructor->getInheritedConstructor())
9894 InheritedFrom = Inherited.getShadowDecl()->getNominatedBaseClass();
9895 if (Entity.getKind() == InitializedEntity::EK_Base) {
9896 S.Diag(Kind.getLocation(), diag::err_missing_default_ctor)
9897 << (InheritedFrom ? 2 : Constructor->isImplicit() ? 1 : 0)
9898 << S.Context.getTypeDeclType(Constructor->getParent())
9899 << /*base=*/0
9900 << Entity.getType()
9901 << InheritedFrom;
9902
9903 RecordDecl *BaseDecl
9904 = Entity.getBaseSpecifier()->getType()->castAs<RecordType>()
9905 ->getDecl();
9906 S.Diag(BaseDecl->getLocation(), diag::note_previous_decl)
9907 << S.Context.getTagDeclType(BaseDecl);
9908 } else {
9909 S.Diag(Kind.getLocation(), diag::err_missing_default_ctor)
9910 << (InheritedFrom ? 2 : Constructor->isImplicit() ? 1 : 0)
9911 << S.Context.getTypeDeclType(Constructor->getParent())
9912 << /*member=*/1
9913 << Entity.getName()
9914 << InheritedFrom;
9915 S.Diag(Entity.getDecl()->getLocation(),
9916 diag::note_member_declared_at);
9917
9918 if (const RecordType *Record
9919 = Entity.getType()->getAs<RecordType>())
9920 S.Diag(Record->getDecl()->getLocation(),
9921 diag::note_previous_decl)
9922 << S.Context.getTagDeclType(Record->getDecl());
9923 }
9924 break;
9925 }
9926
9927 FailedCandidateSet.NoteCandidates(
9928 PartialDiagnosticAt(
9929 Kind.getLocation(),
9930 S.PDiag(diag::err_ovl_no_viable_function_in_init)
9931 << DestType << ArgsRange),
9932 S, OCD_AllCandidates, Args);
9933 break;
9934
9935 case OR_Deleted: {
9936 OverloadCandidateSet::iterator Best;
9937 OverloadingResult Ovl
9938 = FailedCandidateSet.BestViableFunction(S, Kind.getLocation(), Best);
9939 if (Ovl != OR_Deleted) {
9940 S.Diag(Kind.getLocation(), diag::err_ovl_deleted_init)
9941 << DestType << ArgsRange;
9942 llvm_unreachable("Inconsistent overload resolution?");
9943 break;
9944 }
9945
9946 // If this is a defaulted or implicitly-declared function, then
9947 // it was implicitly deleted. Make it clear that the deletion was
9948 // implicit.
9949 if (S.isImplicitlyDeleted(Best->Function))
9950 S.Diag(Kind.getLocation(), diag::err_ovl_deleted_special_init)
9951 << S.getSpecialMember(cast<CXXMethodDecl>(Best->Function))
9952 << DestType << ArgsRange;
9953 else
9954 S.Diag(Kind.getLocation(), diag::err_ovl_deleted_init)
9955 << DestType << ArgsRange;
9956
9957 S.NoteDeletedFunction(Best->Function);
9958 break;
9959 }
9960
9961 case OR_Success:
9962 llvm_unreachable("Conversion did not fail!");
9963 }
9964 }
9965 break;
9966
9967 case FK_DefaultInitOfConst:
9968 if (Entity.getKind() == InitializedEntity::EK_Member &&
9969 isa<CXXConstructorDecl>(S.CurContext)) {
9970 // This is implicit default-initialization of a const member in
9971 // a constructor. Complain that it needs to be explicitly
9972 // initialized.
9973 CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(S.CurContext);
9974 S.Diag(Kind.getLocation(), diag::err_uninitialized_member_in_ctor)
9975 << (Constructor->getInheritedConstructor() ? 2 :
9976 Constructor->isImplicit() ? 1 : 0)
9977 << S.Context.getTypeDeclType(Constructor->getParent())
9978 << /*const=*/1
9979 << Entity.getName();
9980 S.Diag(Entity.getDecl()->getLocation(), diag::note_previous_decl)
9981 << Entity.getName();
9982 } else if (const auto *VD = dyn_cast_if_present<VarDecl>(Entity.getDecl());
9983 VD && VD->isConstexpr()) {
9984 S.Diag(Kind.getLocation(), diag::err_constexpr_var_requires_const_init)
9985 << VD;
9986 } else {
9987 S.Diag(Kind.getLocation(), diag::err_default_init_const)
9988 << DestType << (bool)DestType->getAs<RecordType>();
9989 }
9990 break;
9991
9992 case FK_Incomplete:
9993 S.RequireCompleteType(Kind.getLocation(), FailedIncompleteType,
9994 diag::err_init_incomplete_type);
9995 break;
9996
9997 case FK_ListInitializationFailed: {
9998 // Run the init list checker again to emit diagnostics.
9999 InitListExpr *InitList = cast<InitListExpr>(Args[0]);
10000 diagnoseListInit(S, Entity, InitList);
10001 break;
10002 }
10003
10004 case FK_PlaceholderType: {
10005 // FIXME: Already diagnosed!
10006 break;
10007 }
10008
10009 case FK_ExplicitConstructor: {
10010 S.Diag(Kind.getLocation(), diag::err_selected_explicit_constructor)
10011 << Args[0]->getSourceRange();
10012 OverloadCandidateSet::iterator Best;
10013 OverloadingResult Ovl
10014 = FailedCandidateSet.BestViableFunction(S, Kind.getLocation(), Best);
10015 (void)Ovl;
10016 assert(Ovl == OR_Success && "Inconsistent overload resolution");
10017 CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
10018 S.Diag(CtorDecl->getLocation(),
10019 diag::note_explicit_ctor_deduction_guide_here) << false;
10020 break;
10021 }
10022
10023 case FK_ParenthesizedListInitFailed:
10024 TryOrBuildParenListInitialization(S, Entity, Kind, Args, *this,
10025 /*VerifyOnly=*/false);
10026 break;
10027
10028 case FK_DesignatedInitForNonAggregate:
10029 InitListExpr *InitList = cast<InitListExpr>(Args[0]);
10030 S.Diag(Kind.getLocation(), diag::err_designated_init_for_non_aggregate)
10031 << Entity.getType() << InitList->getSourceRange();
10032 break;
10033 }
10034
10035 PrintInitLocationNote(S, Entity);
10036 return true;
10037 }
10038
dump(raw_ostream & OS) const10039 void InitializationSequence::dump(raw_ostream &OS) const {
10040 switch (SequenceKind) {
10041 case FailedSequence: {
10042 OS << "Failed sequence: ";
10043 switch (Failure) {
10044 case FK_TooManyInitsForReference:
10045 OS << "too many initializers for reference";
10046 break;
10047
10048 case FK_ParenthesizedListInitForReference:
10049 OS << "parenthesized list init for reference";
10050 break;
10051
10052 case FK_ArrayNeedsInitList:
10053 OS << "array requires initializer list";
10054 break;
10055
10056 case FK_AddressOfUnaddressableFunction:
10057 OS << "address of unaddressable function was taken";
10058 break;
10059
10060 case FK_ArrayNeedsInitListOrStringLiteral:
10061 OS << "array requires initializer list or string literal";
10062 break;
10063
10064 case FK_ArrayNeedsInitListOrWideStringLiteral:
10065 OS << "array requires initializer list or wide string literal";
10066 break;
10067
10068 case FK_NarrowStringIntoWideCharArray:
10069 OS << "narrow string into wide char array";
10070 break;
10071
10072 case FK_WideStringIntoCharArray:
10073 OS << "wide string into char array";
10074 break;
10075
10076 case FK_IncompatWideStringIntoWideChar:
10077 OS << "incompatible wide string into wide char array";
10078 break;
10079
10080 case FK_PlainStringIntoUTF8Char:
10081 OS << "plain string literal into char8_t array";
10082 break;
10083
10084 case FK_UTF8StringIntoPlainChar:
10085 OS << "u8 string literal into char array";
10086 break;
10087
10088 case FK_ArrayTypeMismatch:
10089 OS << "array type mismatch";
10090 break;
10091
10092 case FK_NonConstantArrayInit:
10093 OS << "non-constant array initializer";
10094 break;
10095
10096 case FK_AddressOfOverloadFailed:
10097 OS << "address of overloaded function failed";
10098 break;
10099
10100 case FK_ReferenceInitOverloadFailed:
10101 OS << "overload resolution for reference initialization failed";
10102 break;
10103
10104 case FK_NonConstLValueReferenceBindingToTemporary:
10105 OS << "non-const lvalue reference bound to temporary";
10106 break;
10107
10108 case FK_NonConstLValueReferenceBindingToBitfield:
10109 OS << "non-const lvalue reference bound to bit-field";
10110 break;
10111
10112 case FK_NonConstLValueReferenceBindingToVectorElement:
10113 OS << "non-const lvalue reference bound to vector element";
10114 break;
10115
10116 case FK_NonConstLValueReferenceBindingToMatrixElement:
10117 OS << "non-const lvalue reference bound to matrix element";
10118 break;
10119
10120 case FK_NonConstLValueReferenceBindingToUnrelated:
10121 OS << "non-const lvalue reference bound to unrelated type";
10122 break;
10123
10124 case FK_RValueReferenceBindingToLValue:
10125 OS << "rvalue reference bound to an lvalue";
10126 break;
10127
10128 case FK_ReferenceInitDropsQualifiers:
10129 OS << "reference initialization drops qualifiers";
10130 break;
10131
10132 case FK_ReferenceAddrspaceMismatchTemporary:
10133 OS << "reference with mismatching address space bound to temporary";
10134 break;
10135
10136 case FK_ReferenceInitFailed:
10137 OS << "reference initialization failed";
10138 break;
10139
10140 case FK_ConversionFailed:
10141 OS << "conversion failed";
10142 break;
10143
10144 case FK_ConversionFromPropertyFailed:
10145 OS << "conversion from property failed";
10146 break;
10147
10148 case FK_TooManyInitsForScalar:
10149 OS << "too many initializers for scalar";
10150 break;
10151
10152 case FK_ParenthesizedListInitForScalar:
10153 OS << "parenthesized list init for reference";
10154 break;
10155
10156 case FK_ReferenceBindingToInitList:
10157 OS << "referencing binding to initializer list";
10158 break;
10159
10160 case FK_InitListBadDestinationType:
10161 OS << "initializer list for non-aggregate, non-scalar type";
10162 break;
10163
10164 case FK_UserConversionOverloadFailed:
10165 OS << "overloading failed for user-defined conversion";
10166 break;
10167
10168 case FK_ConstructorOverloadFailed:
10169 OS << "constructor overloading failed";
10170 break;
10171
10172 case FK_DefaultInitOfConst:
10173 OS << "default initialization of a const variable";
10174 break;
10175
10176 case FK_Incomplete:
10177 OS << "initialization of incomplete type";
10178 break;
10179
10180 case FK_ListInitializationFailed:
10181 OS << "list initialization checker failure";
10182 break;
10183
10184 case FK_VariableLengthArrayHasInitializer:
10185 OS << "variable length array has an initializer";
10186 break;
10187
10188 case FK_PlaceholderType:
10189 OS << "initializer expression isn't contextually valid";
10190 break;
10191
10192 case FK_ListConstructorOverloadFailed:
10193 OS << "list constructor overloading failed";
10194 break;
10195
10196 case FK_ExplicitConstructor:
10197 OS << "list copy initialization chose explicit constructor";
10198 break;
10199
10200 case FK_ParenthesizedListInitFailed:
10201 OS << "parenthesized list initialization failed";
10202 break;
10203
10204 case FK_DesignatedInitForNonAggregate:
10205 OS << "designated initializer for non-aggregate type";
10206 break;
10207 }
10208 OS << '\n';
10209 return;
10210 }
10211
10212 case DependentSequence:
10213 OS << "Dependent sequence\n";
10214 return;
10215
10216 case NormalSequence:
10217 OS << "Normal sequence: ";
10218 break;
10219 }
10220
10221 for (step_iterator S = step_begin(), SEnd = step_end(); S != SEnd; ++S) {
10222 if (S != step_begin()) {
10223 OS << " -> ";
10224 }
10225
10226 switch (S->Kind) {
10227 case SK_ResolveAddressOfOverloadedFunction:
10228 OS << "resolve address of overloaded function";
10229 break;
10230
10231 case SK_CastDerivedToBasePRValue:
10232 OS << "derived-to-base (prvalue)";
10233 break;
10234
10235 case SK_CastDerivedToBaseXValue:
10236 OS << "derived-to-base (xvalue)";
10237 break;
10238
10239 case SK_CastDerivedToBaseLValue:
10240 OS << "derived-to-base (lvalue)";
10241 break;
10242
10243 case SK_BindReference:
10244 OS << "bind reference to lvalue";
10245 break;
10246
10247 case SK_BindReferenceToTemporary:
10248 OS << "bind reference to a temporary";
10249 break;
10250
10251 case SK_FinalCopy:
10252 OS << "final copy in class direct-initialization";
10253 break;
10254
10255 case SK_ExtraneousCopyToTemporary:
10256 OS << "extraneous C++03 copy to temporary";
10257 break;
10258
10259 case SK_UserConversion:
10260 OS << "user-defined conversion via " << *S->Function.Function;
10261 break;
10262
10263 case SK_QualificationConversionPRValue:
10264 OS << "qualification conversion (prvalue)";
10265 break;
10266
10267 case SK_QualificationConversionXValue:
10268 OS << "qualification conversion (xvalue)";
10269 break;
10270
10271 case SK_QualificationConversionLValue:
10272 OS << "qualification conversion (lvalue)";
10273 break;
10274
10275 case SK_FunctionReferenceConversion:
10276 OS << "function reference conversion";
10277 break;
10278
10279 case SK_AtomicConversion:
10280 OS << "non-atomic-to-atomic conversion";
10281 break;
10282
10283 case SK_ConversionSequence:
10284 OS << "implicit conversion sequence (";
10285 S->ICS->dump(); // FIXME: use OS
10286 OS << ")";
10287 break;
10288
10289 case SK_ConversionSequenceNoNarrowing:
10290 OS << "implicit conversion sequence with narrowing prohibited (";
10291 S->ICS->dump(); // FIXME: use OS
10292 OS << ")";
10293 break;
10294
10295 case SK_ListInitialization:
10296 OS << "list aggregate initialization";
10297 break;
10298
10299 case SK_UnwrapInitList:
10300 OS << "unwrap reference initializer list";
10301 break;
10302
10303 case SK_RewrapInitList:
10304 OS << "rewrap reference initializer list";
10305 break;
10306
10307 case SK_ConstructorInitialization:
10308 OS << "constructor initialization";
10309 break;
10310
10311 case SK_ConstructorInitializationFromList:
10312 OS << "list initialization via constructor";
10313 break;
10314
10315 case SK_ZeroInitialization:
10316 OS << "zero initialization";
10317 break;
10318
10319 case SK_CAssignment:
10320 OS << "C assignment";
10321 break;
10322
10323 case SK_StringInit:
10324 OS << "string initialization";
10325 break;
10326
10327 case SK_ObjCObjectConversion:
10328 OS << "Objective-C object conversion";
10329 break;
10330
10331 case SK_ArrayLoopIndex:
10332 OS << "indexing for array initialization loop";
10333 break;
10334
10335 case SK_ArrayLoopInit:
10336 OS << "array initialization loop";
10337 break;
10338
10339 case SK_ArrayInit:
10340 OS << "array initialization";
10341 break;
10342
10343 case SK_GNUArrayInit:
10344 OS << "array initialization (GNU extension)";
10345 break;
10346
10347 case SK_ParenthesizedArrayInit:
10348 OS << "parenthesized array initialization";
10349 break;
10350
10351 case SK_PassByIndirectCopyRestore:
10352 OS << "pass by indirect copy and restore";
10353 break;
10354
10355 case SK_PassByIndirectRestore:
10356 OS << "pass by indirect restore";
10357 break;
10358
10359 case SK_ProduceObjCObject:
10360 OS << "Objective-C object retension";
10361 break;
10362
10363 case SK_StdInitializerList:
10364 OS << "std::initializer_list from initializer list";
10365 break;
10366
10367 case SK_StdInitializerListConstructorCall:
10368 OS << "list initialization from std::initializer_list";
10369 break;
10370
10371 case SK_OCLSamplerInit:
10372 OS << "OpenCL sampler_t from integer constant";
10373 break;
10374
10375 case SK_OCLZeroOpaqueType:
10376 OS << "OpenCL opaque type from zero";
10377 break;
10378 case SK_ParenthesizedListInit:
10379 OS << "initialization from a parenthesized list of values";
10380 break;
10381 }
10382
10383 OS << " [" << S->Type << ']';
10384 }
10385
10386 OS << '\n';
10387 }
10388
dump() const10389 void InitializationSequence::dump() const {
10390 dump(llvm::errs());
10391 }
10392
DiagnoseNarrowingInInitList(Sema & S,const ImplicitConversionSequence & ICS,QualType PreNarrowingType,QualType EntityType,const Expr * PostInit)10393 static void DiagnoseNarrowingInInitList(Sema &S,
10394 const ImplicitConversionSequence &ICS,
10395 QualType PreNarrowingType,
10396 QualType EntityType,
10397 const Expr *PostInit) {
10398 const StandardConversionSequence *SCS = nullptr;
10399 switch (ICS.getKind()) {
10400 case ImplicitConversionSequence::StandardConversion:
10401 SCS = &ICS.Standard;
10402 break;
10403 case ImplicitConversionSequence::UserDefinedConversion:
10404 SCS = &ICS.UserDefined.After;
10405 break;
10406 case ImplicitConversionSequence::AmbiguousConversion:
10407 case ImplicitConversionSequence::StaticObjectArgumentConversion:
10408 case ImplicitConversionSequence::EllipsisConversion:
10409 case ImplicitConversionSequence::BadConversion:
10410 return;
10411 }
10412
10413 auto MakeDiag = [&](bool IsConstRef, unsigned DefaultDiagID,
10414 unsigned ConstRefDiagID, unsigned WarnDiagID) {
10415 unsigned DiagID;
10416 auto &L = S.getLangOpts();
10417 if (L.CPlusPlus11 &&
10418 (!L.MicrosoftExt || L.isCompatibleWithMSVC(LangOptions::MSVC2015)))
10419 DiagID = IsConstRef ? ConstRefDiagID : DefaultDiagID;
10420 else
10421 DiagID = WarnDiagID;
10422 return S.Diag(PostInit->getBeginLoc(), DiagID)
10423 << PostInit->getSourceRange();
10424 };
10425
10426 // C++11 [dcl.init.list]p7: Check whether this is a narrowing conversion.
10427 APValue ConstantValue;
10428 QualType ConstantType;
10429 switch (SCS->getNarrowingKind(S.Context, PostInit, ConstantValue,
10430 ConstantType)) {
10431 case NK_Not_Narrowing:
10432 case NK_Dependent_Narrowing:
10433 // No narrowing occurred.
10434 return;
10435
10436 case NK_Type_Narrowing: {
10437 // This was a floating-to-integer conversion, which is always considered a
10438 // narrowing conversion even if the value is a constant and can be
10439 // represented exactly as an integer.
10440 QualType T = EntityType.getNonReferenceType();
10441 MakeDiag(T != EntityType, diag::ext_init_list_type_narrowing,
10442 diag::ext_init_list_type_narrowing_const_reference,
10443 diag::warn_init_list_type_narrowing)
10444 << PreNarrowingType.getLocalUnqualifiedType()
10445 << T.getLocalUnqualifiedType();
10446 break;
10447 }
10448
10449 case NK_Constant_Narrowing: {
10450 // A constant value was narrowed.
10451 MakeDiag(EntityType.getNonReferenceType() != EntityType,
10452 diag::ext_init_list_constant_narrowing,
10453 diag::ext_init_list_constant_narrowing_const_reference,
10454 diag::warn_init_list_constant_narrowing)
10455 << ConstantValue.getAsString(S.getASTContext(), ConstantType)
10456 << EntityType.getNonReferenceType().getLocalUnqualifiedType();
10457 break;
10458 }
10459
10460 case NK_Variable_Narrowing: {
10461 // A variable's value may have been narrowed.
10462 MakeDiag(EntityType.getNonReferenceType() != EntityType,
10463 diag::ext_init_list_variable_narrowing,
10464 diag::ext_init_list_variable_narrowing_const_reference,
10465 diag::warn_init_list_variable_narrowing)
10466 << PreNarrowingType.getLocalUnqualifiedType()
10467 << EntityType.getNonReferenceType().getLocalUnqualifiedType();
10468 break;
10469 }
10470 }
10471
10472 SmallString<128> StaticCast;
10473 llvm::raw_svector_ostream OS(StaticCast);
10474 OS << "static_cast<";
10475 if (const TypedefType *TT = EntityType->getAs<TypedefType>()) {
10476 // It's important to use the typedef's name if there is one so that the
10477 // fixit doesn't break code using types like int64_t.
10478 //
10479 // FIXME: This will break if the typedef requires qualification. But
10480 // getQualifiedNameAsString() includes non-machine-parsable components.
10481 OS << *TT->getDecl();
10482 } else if (const BuiltinType *BT = EntityType->getAs<BuiltinType>())
10483 OS << BT->getName(S.getLangOpts());
10484 else {
10485 // Oops, we didn't find the actual type of the variable. Don't emit a fixit
10486 // with a broken cast.
10487 return;
10488 }
10489 OS << ">(";
10490 S.Diag(PostInit->getBeginLoc(), diag::note_init_list_narrowing_silence)
10491 << PostInit->getSourceRange()
10492 << FixItHint::CreateInsertion(PostInit->getBeginLoc(), OS.str())
10493 << FixItHint::CreateInsertion(
10494 S.getLocForEndOfToken(PostInit->getEndLoc()), ")");
10495 }
10496
10497 //===----------------------------------------------------------------------===//
10498 // Initialization helper functions
10499 //===----------------------------------------------------------------------===//
10500 bool
CanPerformCopyInitialization(const InitializedEntity & Entity,ExprResult Init)10501 Sema::CanPerformCopyInitialization(const InitializedEntity &Entity,
10502 ExprResult Init) {
10503 if (Init.isInvalid())
10504 return false;
10505
10506 Expr *InitE = Init.get();
10507 assert(InitE && "No initialization expression");
10508
10509 InitializationKind Kind =
10510 InitializationKind::CreateCopy(InitE->getBeginLoc(), SourceLocation());
10511 InitializationSequence Seq(*this, Entity, Kind, InitE);
10512 return !Seq.Failed();
10513 }
10514
10515 ExprResult
PerformCopyInitialization(const InitializedEntity & Entity,SourceLocation EqualLoc,ExprResult Init,bool TopLevelOfInitList,bool AllowExplicit)10516 Sema::PerformCopyInitialization(const InitializedEntity &Entity,
10517 SourceLocation EqualLoc,
10518 ExprResult Init,
10519 bool TopLevelOfInitList,
10520 bool AllowExplicit) {
10521 if (Init.isInvalid())
10522 return ExprError();
10523
10524 Expr *InitE = Init.get();
10525 assert(InitE && "No initialization expression?");
10526
10527 if (EqualLoc.isInvalid())
10528 EqualLoc = InitE->getBeginLoc();
10529
10530 InitializationKind Kind = InitializationKind::CreateCopy(
10531 InitE->getBeginLoc(), EqualLoc, AllowExplicit);
10532 InitializationSequence Seq(*this, Entity, Kind, InitE, TopLevelOfInitList);
10533
10534 // Prevent infinite recursion when performing parameter copy-initialization.
10535 const bool ShouldTrackCopy =
10536 Entity.isParameterKind() && Seq.isConstructorInitialization();
10537 if (ShouldTrackCopy) {
10538 if (llvm::is_contained(CurrentParameterCopyTypes, Entity.getType())) {
10539 Seq.SetOverloadFailure(
10540 InitializationSequence::FK_ConstructorOverloadFailed,
10541 OR_No_Viable_Function);
10542
10543 // Try to give a meaningful diagnostic note for the problematic
10544 // constructor.
10545 const auto LastStep = Seq.step_end() - 1;
10546 assert(LastStep->Kind ==
10547 InitializationSequence::SK_ConstructorInitialization);
10548 const FunctionDecl *Function = LastStep->Function.Function;
10549 auto Candidate =
10550 llvm::find_if(Seq.getFailedCandidateSet(),
10551 [Function](const OverloadCandidate &Candidate) -> bool {
10552 return Candidate.Viable &&
10553 Candidate.Function == Function &&
10554 Candidate.Conversions.size() > 0;
10555 });
10556 if (Candidate != Seq.getFailedCandidateSet().end() &&
10557 Function->getNumParams() > 0) {
10558 Candidate->Viable = false;
10559 Candidate->FailureKind = ovl_fail_bad_conversion;
10560 Candidate->Conversions[0].setBad(BadConversionSequence::no_conversion,
10561 InitE,
10562 Function->getParamDecl(0)->getType());
10563 }
10564 }
10565 CurrentParameterCopyTypes.push_back(Entity.getType());
10566 }
10567
10568 ExprResult Result = Seq.Perform(*this, Entity, Kind, InitE);
10569
10570 if (ShouldTrackCopy)
10571 CurrentParameterCopyTypes.pop_back();
10572
10573 return Result;
10574 }
10575
10576 /// Determine whether RD is, or is derived from, a specialization of CTD.
isOrIsDerivedFromSpecializationOf(CXXRecordDecl * RD,ClassTemplateDecl * CTD)10577 static bool isOrIsDerivedFromSpecializationOf(CXXRecordDecl *RD,
10578 ClassTemplateDecl *CTD) {
10579 auto NotSpecialization = [&] (const CXXRecordDecl *Candidate) {
10580 auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(Candidate);
10581 return !CTSD || !declaresSameEntity(CTSD->getSpecializedTemplate(), CTD);
10582 };
10583 return !(NotSpecialization(RD) && RD->forallBases(NotSpecialization));
10584 }
10585
DeduceTemplateSpecializationFromInitializer(TypeSourceInfo * TSInfo,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Inits)10586 QualType Sema::DeduceTemplateSpecializationFromInitializer(
10587 TypeSourceInfo *TSInfo, const InitializedEntity &Entity,
10588 const InitializationKind &Kind, MultiExprArg Inits) {
10589 auto *DeducedTST = dyn_cast<DeducedTemplateSpecializationType>(
10590 TSInfo->getType()->getContainedDeducedType());
10591 assert(DeducedTST && "not a deduced template specialization type");
10592
10593 auto TemplateName = DeducedTST->getTemplateName();
10594 if (TemplateName.isDependent())
10595 return SubstAutoTypeDependent(TSInfo->getType());
10596
10597 // We can only perform deduction for class templates.
10598 auto *Template =
10599 dyn_cast_or_null<ClassTemplateDecl>(TemplateName.getAsTemplateDecl());
10600 if (!Template) {
10601 Diag(Kind.getLocation(),
10602 diag::err_deduced_non_class_template_specialization_type)
10603 << (int)getTemplateNameKindForDiagnostics(TemplateName) << TemplateName;
10604 if (auto *TD = TemplateName.getAsTemplateDecl())
10605 NoteTemplateLocation(*TD);
10606 return QualType();
10607 }
10608
10609 // Can't deduce from dependent arguments.
10610 if (Expr::hasAnyTypeDependentArguments(Inits)) {
10611 Diag(TSInfo->getTypeLoc().getBeginLoc(),
10612 diag::warn_cxx14_compat_class_template_argument_deduction)
10613 << TSInfo->getTypeLoc().getSourceRange() << 0;
10614 return SubstAutoTypeDependent(TSInfo->getType());
10615 }
10616
10617 // FIXME: Perform "exact type" matching first, per CWG discussion?
10618 // Or implement this via an implied 'T(T) -> T' deduction guide?
10619
10620 // FIXME: Do we need/want a std::initializer_list<T> special case?
10621
10622 // Look up deduction guides, including those synthesized from constructors.
10623 //
10624 // C++1z [over.match.class.deduct]p1:
10625 // A set of functions and function templates is formed comprising:
10626 // - For each constructor of the class template designated by the
10627 // template-name, a function template [...]
10628 // - For each deduction-guide, a function or function template [...]
10629 DeclarationNameInfo NameInfo(
10630 Context.DeclarationNames.getCXXDeductionGuideName(Template),
10631 TSInfo->getTypeLoc().getEndLoc());
10632 LookupResult Guides(*this, NameInfo, LookupOrdinaryName);
10633 LookupQualifiedName(Guides, Template->getDeclContext());
10634
10635 // FIXME: Do not diagnose inaccessible deduction guides. The standard isn't
10636 // clear on this, but they're not found by name so access does not apply.
10637 Guides.suppressDiagnostics();
10638
10639 // Figure out if this is list-initialization.
10640 InitListExpr *ListInit =
10641 (Inits.size() == 1 && Kind.getKind() != InitializationKind::IK_Direct)
10642 ? dyn_cast<InitListExpr>(Inits[0])
10643 : nullptr;
10644
10645 // C++1z [over.match.class.deduct]p1:
10646 // Initialization and overload resolution are performed as described in
10647 // [dcl.init] and [over.match.ctor], [over.match.copy], or [over.match.list]
10648 // (as appropriate for the type of initialization performed) for an object
10649 // of a hypothetical class type, where the selected functions and function
10650 // templates are considered to be the constructors of that class type
10651 //
10652 // Since we know we're initializing a class type of a type unrelated to that
10653 // of the initializer, this reduces to something fairly reasonable.
10654 OverloadCandidateSet Candidates(Kind.getLocation(),
10655 OverloadCandidateSet::CSK_Normal);
10656 OverloadCandidateSet::iterator Best;
10657
10658 bool AllowExplicit = !Kind.isCopyInit() || ListInit;
10659
10660 // Return true if the candidate is added successfully, false otherwise.
10661 auto addDeductionCandidate = [&](FunctionTemplateDecl *TD,
10662 CXXDeductionGuideDecl *GD,
10663 DeclAccessPair FoundDecl,
10664 bool OnlyListConstructors,
10665 bool AllowAggregateDeductionCandidate) {
10666 // C++ [over.match.ctor]p1: (non-list copy-initialization from non-class)
10667 // For copy-initialization, the candidate functions are all the
10668 // converting constructors (12.3.1) of that class.
10669 // C++ [over.match.copy]p1: (non-list copy-initialization from class)
10670 // The converting constructors of T are candidate functions.
10671 if (!AllowExplicit) {
10672 // Overload resolution checks whether the deduction guide is declared
10673 // explicit for us.
10674
10675 // When looking for a converting constructor, deduction guides that
10676 // could never be called with one argument are not interesting to
10677 // check or note.
10678 if (GD->getMinRequiredArguments() > 1 ||
10679 (GD->getNumParams() == 0 && !GD->isVariadic()))
10680 return;
10681 }
10682
10683 // C++ [over.match.list]p1.1: (first phase list initialization)
10684 // Initially, the candidate functions are the initializer-list
10685 // constructors of the class T
10686 if (OnlyListConstructors && !isInitListConstructor(GD))
10687 return;
10688
10689 if (!AllowAggregateDeductionCandidate &&
10690 GD->getDeductionCandidateKind() == DeductionCandidate::Aggregate)
10691 return;
10692
10693 // C++ [over.match.list]p1.2: (second phase list initialization)
10694 // the candidate functions are all the constructors of the class T
10695 // C++ [over.match.ctor]p1: (all other cases)
10696 // the candidate functions are all the constructors of the class of
10697 // the object being initialized
10698
10699 // C++ [over.best.ics]p4:
10700 // When [...] the constructor [...] is a candidate by
10701 // - [over.match.copy] (in all cases)
10702 // FIXME: The "second phase of [over.match.list] case can also
10703 // theoretically happen here, but it's not clear whether we can
10704 // ever have a parameter of the right type.
10705 bool SuppressUserConversions = Kind.isCopyInit();
10706
10707 if (TD) {
10708 SmallVector<Expr *, 8> TmpInits;
10709 for (Expr *E : Inits)
10710 if (auto *DI = dyn_cast<DesignatedInitExpr>(E))
10711 TmpInits.push_back(DI->getInit());
10712 else
10713 TmpInits.push_back(E);
10714 AddTemplateOverloadCandidate(
10715 TD, FoundDecl, /*ExplicitArgs=*/nullptr, TmpInits, Candidates,
10716 SuppressUserConversions,
10717 /*PartialOverloading=*/false, AllowExplicit, ADLCallKind::NotADL,
10718 /*PO=*/{}, AllowAggregateDeductionCandidate);
10719 } else {
10720 AddOverloadCandidate(GD, FoundDecl, Inits, Candidates,
10721 SuppressUserConversions,
10722 /*PartialOverloading=*/false, AllowExplicit);
10723 }
10724 };
10725
10726 bool FoundDeductionGuide = false;
10727
10728 auto TryToResolveOverload =
10729 [&](bool OnlyListConstructors) -> OverloadingResult {
10730 Candidates.clear(OverloadCandidateSet::CSK_Normal);
10731 bool HasAnyDeductionGuide = false;
10732
10733 auto SynthesizeAggrGuide = [&](InitListExpr *ListInit) {
10734 auto *Pattern = Template;
10735 while (Pattern->getInstantiatedFromMemberTemplate()) {
10736 if (Pattern->isMemberSpecialization())
10737 break;
10738 Pattern = Pattern->getInstantiatedFromMemberTemplate();
10739 }
10740
10741 auto *RD = cast<CXXRecordDecl>(Pattern->getTemplatedDecl());
10742 if (!(RD->getDefinition() && RD->isAggregate()))
10743 return;
10744 QualType Ty = Context.getRecordType(RD);
10745 SmallVector<QualType, 8> ElementTypes;
10746
10747 InitListChecker CheckInitList(*this, Entity, ListInit, Ty, ElementTypes);
10748 if (!CheckInitList.HadError()) {
10749 // C++ [over.match.class.deduct]p1.8:
10750 // if e_i is of array type and x_i is a braced-init-list, T_i is an
10751 // rvalue reference to the declared type of e_i and
10752 // C++ [over.match.class.deduct]p1.9:
10753 // if e_i is of array type and x_i is a bstring-literal, T_i is an
10754 // lvalue reference to the const-qualified declared type of e_i and
10755 // C++ [over.match.class.deduct]p1.10:
10756 // otherwise, T_i is the declared type of e_i
10757 for (int I = 0, E = ListInit->getNumInits();
10758 I < E && !isa<PackExpansionType>(ElementTypes[I]); ++I)
10759 if (ElementTypes[I]->isArrayType()) {
10760 if (isa<InitListExpr>(ListInit->getInit(I)))
10761 ElementTypes[I] = Context.getRValueReferenceType(ElementTypes[I]);
10762 else if (isa<StringLiteral>(
10763 ListInit->getInit(I)->IgnoreParenImpCasts()))
10764 ElementTypes[I] =
10765 Context.getLValueReferenceType(ElementTypes[I].withConst());
10766 }
10767
10768 llvm::FoldingSetNodeID ID;
10769 ID.AddPointer(Template);
10770 for (auto &T : ElementTypes)
10771 T.getCanonicalType().Profile(ID);
10772 unsigned Hash = ID.ComputeHash();
10773 if (AggregateDeductionCandidates.count(Hash) == 0) {
10774 if (FunctionTemplateDecl *TD =
10775 DeclareImplicitDeductionGuideFromInitList(
10776 Template, ElementTypes,
10777 TSInfo->getTypeLoc().getEndLoc())) {
10778 auto *GD = cast<CXXDeductionGuideDecl>(TD->getTemplatedDecl());
10779 GD->setDeductionCandidateKind(DeductionCandidate::Aggregate);
10780 AggregateDeductionCandidates[Hash] = GD;
10781 addDeductionCandidate(TD, GD, DeclAccessPair::make(TD, AS_public),
10782 OnlyListConstructors,
10783 /*AllowAggregateDeductionCandidate=*/true);
10784 }
10785 } else {
10786 CXXDeductionGuideDecl *GD = AggregateDeductionCandidates[Hash];
10787 FunctionTemplateDecl *TD = GD->getDescribedFunctionTemplate();
10788 assert(TD && "aggregate deduction candidate is function template");
10789 addDeductionCandidate(TD, GD, DeclAccessPair::make(TD, AS_public),
10790 OnlyListConstructors,
10791 /*AllowAggregateDeductionCandidate=*/true);
10792 }
10793 HasAnyDeductionGuide = true;
10794 }
10795 };
10796
10797 for (auto I = Guides.begin(), E = Guides.end(); I != E; ++I) {
10798 NamedDecl *D = (*I)->getUnderlyingDecl();
10799 if (D->isInvalidDecl())
10800 continue;
10801
10802 auto *TD = dyn_cast<FunctionTemplateDecl>(D);
10803 auto *GD = dyn_cast_if_present<CXXDeductionGuideDecl>(
10804 TD ? TD->getTemplatedDecl() : dyn_cast<FunctionDecl>(D));
10805 if (!GD)
10806 continue;
10807
10808 if (!GD->isImplicit())
10809 HasAnyDeductionGuide = true;
10810
10811 addDeductionCandidate(TD, GD, I.getPair(), OnlyListConstructors,
10812 /*AllowAggregateDeductionCandidate=*/false);
10813 }
10814
10815 // C++ [over.match.class.deduct]p1.4:
10816 // if C is defined and its definition satisfies the conditions for an
10817 // aggregate class ([dcl.init.aggr]) with the assumption that any
10818 // dependent base class has no virtual functions and no virtual base
10819 // classes, and the initializer is a non-empty braced-init-list or
10820 // parenthesized expression-list, and there are no deduction-guides for
10821 // C, the set contains an additional function template, called the
10822 // aggregate deduction candidate, defined as follows.
10823 if (getLangOpts().CPlusPlus20 && !HasAnyDeductionGuide) {
10824 if (ListInit && ListInit->getNumInits()) {
10825 SynthesizeAggrGuide(ListInit);
10826 } else if (Inits.size()) { // parenthesized expression-list
10827 // Inits are expressions inside the parentheses. We don't have
10828 // the parentheses source locations, use the begin/end of Inits as the
10829 // best heuristic.
10830 InitListExpr TempListInit(getASTContext(), Inits.front()->getBeginLoc(),
10831 Inits, Inits.back()->getEndLoc());
10832 SynthesizeAggrGuide(&TempListInit);
10833 }
10834 }
10835
10836 FoundDeductionGuide = FoundDeductionGuide || HasAnyDeductionGuide;
10837
10838 return Candidates.BestViableFunction(*this, Kind.getLocation(), Best);
10839 };
10840
10841 OverloadingResult Result = OR_No_Viable_Function;
10842
10843 // C++11 [over.match.list]p1, per DR1467: for list-initialization, first
10844 // try initializer-list constructors.
10845 if (ListInit) {
10846 bool TryListConstructors = true;
10847
10848 // Try list constructors unless the list is empty and the class has one or
10849 // more default constructors, in which case those constructors win.
10850 if (!ListInit->getNumInits()) {
10851 for (NamedDecl *D : Guides) {
10852 auto *FD = dyn_cast<FunctionDecl>(D->getUnderlyingDecl());
10853 if (FD && FD->getMinRequiredArguments() == 0) {
10854 TryListConstructors = false;
10855 break;
10856 }
10857 }
10858 } else if (ListInit->getNumInits() == 1) {
10859 // C++ [over.match.class.deduct]:
10860 // As an exception, the first phase in [over.match.list] (considering
10861 // initializer-list constructors) is omitted if the initializer list
10862 // consists of a single expression of type cv U, where U is a
10863 // specialization of C or a class derived from a specialization of C.
10864 Expr *E = ListInit->getInit(0);
10865 auto *RD = E->getType()->getAsCXXRecordDecl();
10866 if (!isa<InitListExpr>(E) && RD &&
10867 isCompleteType(Kind.getLocation(), E->getType()) &&
10868 isOrIsDerivedFromSpecializationOf(RD, Template))
10869 TryListConstructors = false;
10870 }
10871
10872 if (TryListConstructors)
10873 Result = TryToResolveOverload(/*OnlyListConstructor*/true);
10874 // Then unwrap the initializer list and try again considering all
10875 // constructors.
10876 Inits = MultiExprArg(ListInit->getInits(), ListInit->getNumInits());
10877 }
10878
10879 // If list-initialization fails, or if we're doing any other kind of
10880 // initialization, we (eventually) consider constructors.
10881 if (Result == OR_No_Viable_Function)
10882 Result = TryToResolveOverload(/*OnlyListConstructor*/false);
10883
10884 switch (Result) {
10885 case OR_Ambiguous:
10886 // FIXME: For list-initialization candidates, it'd usually be better to
10887 // list why they were not viable when given the initializer list itself as
10888 // an argument.
10889 Candidates.NoteCandidates(
10890 PartialDiagnosticAt(
10891 Kind.getLocation(),
10892 PDiag(diag::err_deduced_class_template_ctor_ambiguous)
10893 << TemplateName),
10894 *this, OCD_AmbiguousCandidates, Inits);
10895 return QualType();
10896
10897 case OR_No_Viable_Function: {
10898 CXXRecordDecl *Primary =
10899 cast<ClassTemplateDecl>(Template)->getTemplatedDecl();
10900 bool Complete =
10901 isCompleteType(Kind.getLocation(), Context.getTypeDeclType(Primary));
10902 Candidates.NoteCandidates(
10903 PartialDiagnosticAt(
10904 Kind.getLocation(),
10905 PDiag(Complete ? diag::err_deduced_class_template_ctor_no_viable
10906 : diag::err_deduced_class_template_incomplete)
10907 << TemplateName << !Guides.empty()),
10908 *this, OCD_AllCandidates, Inits);
10909 return QualType();
10910 }
10911
10912 case OR_Deleted: {
10913 Diag(Kind.getLocation(), diag::err_deduced_class_template_deleted)
10914 << TemplateName;
10915 NoteDeletedFunction(Best->Function);
10916 return QualType();
10917 }
10918
10919 case OR_Success:
10920 // C++ [over.match.list]p1:
10921 // In copy-list-initialization, if an explicit constructor is chosen, the
10922 // initialization is ill-formed.
10923 if (Kind.isCopyInit() && ListInit &&
10924 cast<CXXDeductionGuideDecl>(Best->Function)->isExplicit()) {
10925 bool IsDeductionGuide = !Best->Function->isImplicit();
10926 Diag(Kind.getLocation(), diag::err_deduced_class_template_explicit)
10927 << TemplateName << IsDeductionGuide;
10928 Diag(Best->Function->getLocation(),
10929 diag::note_explicit_ctor_deduction_guide_here)
10930 << IsDeductionGuide;
10931 return QualType();
10932 }
10933
10934 // Make sure we didn't select an unusable deduction guide, and mark it
10935 // as referenced.
10936 DiagnoseUseOfDecl(Best->FoundDecl, Kind.getLocation());
10937 MarkFunctionReferenced(Kind.getLocation(), Best->Function);
10938 break;
10939 }
10940
10941 // C++ [dcl.type.class.deduct]p1:
10942 // The placeholder is replaced by the return type of the function selected
10943 // by overload resolution for class template deduction.
10944 QualType DeducedType =
10945 SubstAutoType(TSInfo->getType(), Best->Function->getReturnType());
10946 Diag(TSInfo->getTypeLoc().getBeginLoc(),
10947 diag::warn_cxx14_compat_class_template_argument_deduction)
10948 << TSInfo->getTypeLoc().getSourceRange() << 1 << DeducedType;
10949
10950 // Warn if CTAD was used on a type that does not have any user-defined
10951 // deduction guides.
10952 if (!FoundDeductionGuide) {
10953 Diag(TSInfo->getTypeLoc().getBeginLoc(),
10954 diag::warn_ctad_maybe_unsupported)
10955 << TemplateName;
10956 Diag(Template->getLocation(), diag::note_suppress_ctad_maybe_unsupported);
10957 }
10958
10959 return DeducedType;
10960 }
10961