1 //===--- SemaInit.cpp - Semantic Analysis for Initializers ----------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements semantic analysis for initializers.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "clang/AST/ASTContext.h"
14 #include "clang/AST/DeclObjC.h"
15 #include "clang/AST/ExprCXX.h"
16 #include "clang/AST/ExprObjC.h"
17 #include "clang/AST/ExprOpenMP.h"
18 #include "clang/AST/TypeLoc.h"
19 #include "clang/Basic/CharInfo.h"
20 #include "clang/Basic/SourceManager.h"
21 #include "clang/Basic/TargetInfo.h"
22 #include "clang/Sema/Designator.h"
23 #include "clang/Sema/Initialization.h"
24 #include "clang/Sema/Lookup.h"
25 #include "clang/Sema/SemaInternal.h"
26 #include "llvm/ADT/APInt.h"
27 #include "llvm/ADT/SmallString.h"
28 #include "llvm/Support/ErrorHandling.h"
29 #include "llvm/Support/raw_ostream.h"
30
31 using namespace clang;
32
33 //===----------------------------------------------------------------------===//
34 // Sema Initialization Checking
35 //===----------------------------------------------------------------------===//
36
37 /// Check whether T is compatible with a wide character type (wchar_t,
38 /// char16_t or char32_t).
IsWideCharCompatible(QualType T,ASTContext & Context)39 static bool IsWideCharCompatible(QualType T, ASTContext &Context) {
40 if (Context.typesAreCompatible(Context.getWideCharType(), T))
41 return true;
42 if (Context.getLangOpts().CPlusPlus || Context.getLangOpts().C11) {
43 return Context.typesAreCompatible(Context.Char16Ty, T) ||
44 Context.typesAreCompatible(Context.Char32Ty, T);
45 }
46 return false;
47 }
48
49 enum StringInitFailureKind {
50 SIF_None,
51 SIF_NarrowStringIntoWideChar,
52 SIF_WideStringIntoChar,
53 SIF_IncompatWideStringIntoWideChar,
54 SIF_UTF8StringIntoPlainChar,
55 SIF_PlainStringIntoUTF8Char,
56 SIF_Other
57 };
58
59 /// Check whether the array of type AT can be initialized by the Init
60 /// expression by means of string initialization. Returns SIF_None if so,
61 /// otherwise returns a StringInitFailureKind that describes why the
62 /// initialization would not work.
IsStringInit(Expr * Init,const ArrayType * AT,ASTContext & Context)63 static StringInitFailureKind IsStringInit(Expr *Init, const ArrayType *AT,
64 ASTContext &Context) {
65 if (!isa<ConstantArrayType>(AT) && !isa<IncompleteArrayType>(AT))
66 return SIF_Other;
67
68 // See if this is a string literal or @encode.
69 Init = Init->IgnoreParens();
70
71 // Handle @encode, which is a narrow string.
72 if (isa<ObjCEncodeExpr>(Init) && AT->getElementType()->isCharType())
73 return SIF_None;
74
75 // Otherwise we can only handle string literals.
76 StringLiteral *SL = dyn_cast<StringLiteral>(Init);
77 if (!SL)
78 return SIF_Other;
79
80 const QualType ElemTy =
81 Context.getCanonicalType(AT->getElementType()).getUnqualifiedType();
82
83 switch (SL->getKind()) {
84 case StringLiteral::UTF8:
85 // char8_t array can be initialized with a UTF-8 string.
86 if (ElemTy->isChar8Type())
87 return SIF_None;
88 LLVM_FALLTHROUGH;
89 case StringLiteral::Ascii:
90 // char array can be initialized with a narrow string.
91 // Only allow char x[] = "foo"; not char x[] = L"foo";
92 if (ElemTy->isCharType())
93 return (SL->getKind() == StringLiteral::UTF8 &&
94 Context.getLangOpts().Char8)
95 ? SIF_UTF8StringIntoPlainChar
96 : SIF_None;
97 if (ElemTy->isChar8Type())
98 return SIF_PlainStringIntoUTF8Char;
99 if (IsWideCharCompatible(ElemTy, Context))
100 return SIF_NarrowStringIntoWideChar;
101 return SIF_Other;
102 // C99 6.7.8p15 (with correction from DR343), or C11 6.7.9p15:
103 // "An array with element type compatible with a qualified or unqualified
104 // version of wchar_t, char16_t, or char32_t may be initialized by a wide
105 // string literal with the corresponding encoding prefix (L, u, or U,
106 // respectively), optionally enclosed in braces.
107 case StringLiteral::UTF16:
108 if (Context.typesAreCompatible(Context.Char16Ty, ElemTy))
109 return SIF_None;
110 if (ElemTy->isCharType() || ElemTy->isChar8Type())
111 return SIF_WideStringIntoChar;
112 if (IsWideCharCompatible(ElemTy, Context))
113 return SIF_IncompatWideStringIntoWideChar;
114 return SIF_Other;
115 case StringLiteral::UTF32:
116 if (Context.typesAreCompatible(Context.Char32Ty, ElemTy))
117 return SIF_None;
118 if (ElemTy->isCharType() || ElemTy->isChar8Type())
119 return SIF_WideStringIntoChar;
120 if (IsWideCharCompatible(ElemTy, Context))
121 return SIF_IncompatWideStringIntoWideChar;
122 return SIF_Other;
123 case StringLiteral::Wide:
124 if (Context.typesAreCompatible(Context.getWideCharType(), ElemTy))
125 return SIF_None;
126 if (ElemTy->isCharType() || ElemTy->isChar8Type())
127 return SIF_WideStringIntoChar;
128 if (IsWideCharCompatible(ElemTy, Context))
129 return SIF_IncompatWideStringIntoWideChar;
130 return SIF_Other;
131 }
132
133 llvm_unreachable("missed a StringLiteral kind?");
134 }
135
IsStringInit(Expr * init,QualType declType,ASTContext & Context)136 static StringInitFailureKind IsStringInit(Expr *init, QualType declType,
137 ASTContext &Context) {
138 const ArrayType *arrayType = Context.getAsArrayType(declType);
139 if (!arrayType)
140 return SIF_Other;
141 return IsStringInit(init, arrayType, Context);
142 }
143
IsStringInit(Expr * Init,const ArrayType * AT)144 bool Sema::IsStringInit(Expr *Init, const ArrayType *AT) {
145 return ::IsStringInit(Init, AT, Context) == SIF_None;
146 }
147
148 /// Update the type of a string literal, including any surrounding parentheses,
149 /// to match the type of the object which it is initializing.
updateStringLiteralType(Expr * E,QualType Ty)150 static void updateStringLiteralType(Expr *E, QualType Ty) {
151 while (true) {
152 E->setType(Ty);
153 E->setValueKind(VK_RValue);
154 if (isa<StringLiteral>(E) || isa<ObjCEncodeExpr>(E)) {
155 break;
156 } else if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
157 E = PE->getSubExpr();
158 } else if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
159 assert(UO->getOpcode() == UO_Extension);
160 E = UO->getSubExpr();
161 } else if (GenericSelectionExpr *GSE = dyn_cast<GenericSelectionExpr>(E)) {
162 E = GSE->getResultExpr();
163 } else if (ChooseExpr *CE = dyn_cast<ChooseExpr>(E)) {
164 E = CE->getChosenSubExpr();
165 } else {
166 llvm_unreachable("unexpected expr in string literal init");
167 }
168 }
169 }
170
171 /// Fix a compound literal initializing an array so it's correctly marked
172 /// as an rvalue.
updateGNUCompoundLiteralRValue(Expr * E)173 static void updateGNUCompoundLiteralRValue(Expr *E) {
174 while (true) {
175 E->setValueKind(VK_RValue);
176 if (isa<CompoundLiteralExpr>(E)) {
177 break;
178 } else if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
179 E = PE->getSubExpr();
180 } else if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
181 assert(UO->getOpcode() == UO_Extension);
182 E = UO->getSubExpr();
183 } else if (GenericSelectionExpr *GSE = dyn_cast<GenericSelectionExpr>(E)) {
184 E = GSE->getResultExpr();
185 } else if (ChooseExpr *CE = dyn_cast<ChooseExpr>(E)) {
186 E = CE->getChosenSubExpr();
187 } else {
188 llvm_unreachable("unexpected expr in array compound literal init");
189 }
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(IAT->getElementType(),
206 ConstVal, nullptr,
207 ArrayType::Normal, 0);
208 updateStringLiteralType(Str, DeclT);
209 return;
210 }
211
212 const ConstantArrayType *CAT = cast<ConstantArrayType>(AT);
213
214 // We have an array of character type with known size. However,
215 // the size may be smaller or larger than the string we are initializing.
216 // FIXME: Avoid truncation for 64-bit length strings.
217 if (S.getLangOpts().CPlusPlus) {
218 if (StringLiteral *SL = dyn_cast<StringLiteral>(Str->IgnoreParens())) {
219 // For Pascal strings it's OK to strip off the terminating null character,
220 // so the example below is valid:
221 //
222 // unsigned char a[2] = "\pa";
223 if (SL->isPascal())
224 StrLength--;
225 }
226
227 // [dcl.init.string]p2
228 if (StrLength > CAT->getSize().getZExtValue())
229 S.Diag(Str->getBeginLoc(),
230 diag::err_initializer_string_for_char_array_too_long)
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
getDummyInit()293 NoInitExpr *getDummyInit() {
294 if (!DummyExpr)
295 DummyExpr = new (SemaRef.Context) NoInitExpr(SemaRef.Context.VoidTy);
296 return DummyExpr;
297 }
298
299 void CheckImplicitInitList(const InitializedEntity &Entity,
300 InitListExpr *ParentIList, QualType T,
301 unsigned &Index, InitListExpr *StructuredList,
302 unsigned &StructuredIndex);
303 void CheckExplicitInitList(const InitializedEntity &Entity,
304 InitListExpr *IList, QualType &T,
305 InitListExpr *StructuredList,
306 bool TopLevelObject = false);
307 void CheckListElementTypes(const InitializedEntity &Entity,
308 InitListExpr *IList, QualType &DeclType,
309 bool SubobjectIsDesignatorContext,
310 unsigned &Index,
311 InitListExpr *StructuredList,
312 unsigned &StructuredIndex,
313 bool TopLevelObject = false);
314 void CheckSubElementType(const InitializedEntity &Entity,
315 InitListExpr *IList, QualType ElemType,
316 unsigned &Index,
317 InitListExpr *StructuredList,
318 unsigned &StructuredIndex);
319 void CheckComplexType(const InitializedEntity &Entity,
320 InitListExpr *IList, QualType DeclType,
321 unsigned &Index,
322 InitListExpr *StructuredList,
323 unsigned &StructuredIndex);
324 void CheckScalarType(const InitializedEntity &Entity,
325 InitListExpr *IList, QualType DeclType,
326 unsigned &Index,
327 InitListExpr *StructuredList,
328 unsigned &StructuredIndex);
329 void CheckReferenceType(const InitializedEntity &Entity,
330 InitListExpr *IList, QualType DeclType,
331 unsigned &Index,
332 InitListExpr *StructuredList,
333 unsigned &StructuredIndex);
334 void CheckVectorType(const InitializedEntity &Entity,
335 InitListExpr *IList, QualType DeclType, unsigned &Index,
336 InitListExpr *StructuredList,
337 unsigned &StructuredIndex);
338 void CheckStructUnionTypes(const InitializedEntity &Entity,
339 InitListExpr *IList, QualType DeclType,
340 CXXRecordDecl::base_class_range Bases,
341 RecordDecl::field_iterator Field,
342 bool SubobjectIsDesignatorContext, unsigned &Index,
343 InitListExpr *StructuredList,
344 unsigned &StructuredIndex,
345 bool TopLevelObject = false);
346 void CheckArrayType(const InitializedEntity &Entity,
347 InitListExpr *IList, QualType &DeclType,
348 llvm::APSInt elementIndex,
349 bool SubobjectIsDesignatorContext, unsigned &Index,
350 InitListExpr *StructuredList,
351 unsigned &StructuredIndex);
352 bool CheckDesignatedInitializer(const InitializedEntity &Entity,
353 InitListExpr *IList, DesignatedInitExpr *DIE,
354 unsigned DesigIdx,
355 QualType &CurrentObjectType,
356 RecordDecl::field_iterator *NextField,
357 llvm::APSInt *NextElementIndex,
358 unsigned &Index,
359 InitListExpr *StructuredList,
360 unsigned &StructuredIndex,
361 bool FinishSubobjectInit,
362 bool TopLevelObject);
363 InitListExpr *getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
364 QualType CurrentObjectType,
365 InitListExpr *StructuredList,
366 unsigned StructuredIndex,
367 SourceRange InitRange,
368 bool IsFullyOverwritten = false);
369 void UpdateStructuredListElement(InitListExpr *StructuredList,
370 unsigned &StructuredIndex,
371 Expr *expr);
372 InitListExpr *createInitListExpr(QualType CurrentObjectType,
373 SourceRange InitRange,
374 unsigned ExpectedNumInits);
375 int numArrayElements(QualType DeclType);
376 int numStructUnionElements(QualType DeclType);
377
378 ExprResult PerformEmptyInit(SourceLocation Loc,
379 const InitializedEntity &Entity);
380
381 /// Diagnose that OldInit (or part thereof) has been overridden by NewInit.
diagnoseInitOverride(Expr * OldInit,SourceRange NewInitRange,bool FullyOverwritten=true)382 void diagnoseInitOverride(Expr *OldInit, SourceRange NewInitRange,
383 bool FullyOverwritten = true) {
384 // Overriding an initializer via a designator is valid with C99 designated
385 // initializers, but ill-formed with C++20 designated initializers.
386 unsigned DiagID = SemaRef.getLangOpts().CPlusPlus
387 ? diag::ext_initializer_overrides
388 : diag::warn_initializer_overrides;
389
390 if (InOverloadResolution && SemaRef.getLangOpts().CPlusPlus) {
391 // In overload resolution, we have to strictly enforce the rules, and so
392 // don't allow any overriding of prior initializers. This matters for a
393 // case such as:
394 //
395 // union U { int a, b; };
396 // struct S { int a, b; };
397 // void f(U), f(S);
398 //
399 // Here, f({.a = 1, .b = 2}) is required to call the struct overload. For
400 // consistency, we disallow all overriding of prior initializers in
401 // overload resolution, not only overriding of union members.
402 hadError = true;
403 } else if (OldInit->getType().isDestructedType() && !FullyOverwritten) {
404 // If we'll be keeping around the old initializer but overwriting part of
405 // the object it initialized, and that object is not trivially
406 // destructible, this can leak. Don't allow that, not even as an
407 // extension.
408 //
409 // FIXME: It might be reasonable to allow this in cases where the part of
410 // the initializer that we're overriding has trivial destruction.
411 DiagID = diag::err_initializer_overrides_destructed;
412 } else if (!OldInit->getSourceRange().isValid()) {
413 // We need to check on source range validity because the previous
414 // initializer does not have to be an explicit initializer. e.g.,
415 //
416 // struct P { int a, b; };
417 // struct PP { struct P p } l = { { .a = 2 }, .p.b = 3 };
418 //
419 // There is an overwrite taking place because the first braced initializer
420 // list "{ .a = 2 }" already provides value for .p.b (which is zero).
421 //
422 // Such overwrites are harmless, so we don't diagnose them. (Note that in
423 // C++, this cannot be reached unless we've already seen and diagnosed a
424 // different conformance issue, such as a mixture of designated and
425 // non-designated initializers or a multi-level designator.)
426 return;
427 }
428
429 if (!VerifyOnly) {
430 SemaRef.Diag(NewInitRange.getBegin(), DiagID)
431 << NewInitRange << FullyOverwritten << OldInit->getType();
432 SemaRef.Diag(OldInit->getBeginLoc(), diag::note_previous_initializer)
433 << (OldInit->HasSideEffects(SemaRef.Context) && FullyOverwritten)
434 << OldInit->getSourceRange();
435 }
436 }
437
438 // Explanation on the "FillWithNoInit" mode:
439 //
440 // Assume we have the following definitions (Case#1):
441 // struct P { char x[6][6]; } xp = { .x[1] = "bar" };
442 // struct PP { struct P lp; } l = { .lp = xp, .lp.x[1][2] = 'f' };
443 //
444 // l.lp.x[1][0..1] should not be filled with implicit initializers because the
445 // "base" initializer "xp" will provide values for them; l.lp.x[1] will be "baf".
446 //
447 // But if we have (Case#2):
448 // struct PP l = { .lp = xp, .lp.x[1] = { [2] = 'f' } };
449 //
450 // l.lp.x[1][0..1] are implicitly initialized and do not use values from the
451 // "base" initializer; l.lp.x[1] will be "\0\0f\0\0\0".
452 //
453 // To distinguish Case#1 from Case#2, and also to avoid leaving many "holes"
454 // in the InitListExpr, the "holes" in Case#1 are filled not with empty
455 // initializers but with special "NoInitExpr" place holders, which tells the
456 // CodeGen not to generate any initializers for these parts.
457 void FillInEmptyInitForBase(unsigned Init, const CXXBaseSpecifier &Base,
458 const InitializedEntity &ParentEntity,
459 InitListExpr *ILE, bool &RequiresSecondPass,
460 bool FillWithNoInit);
461 void FillInEmptyInitForField(unsigned Init, FieldDecl *Field,
462 const InitializedEntity &ParentEntity,
463 InitListExpr *ILE, bool &RequiresSecondPass,
464 bool FillWithNoInit = false);
465 void FillInEmptyInitializations(const InitializedEntity &Entity,
466 InitListExpr *ILE, bool &RequiresSecondPass,
467 InitListExpr *OuterILE, unsigned OuterIndex,
468 bool FillWithNoInit = false);
469 bool CheckFlexibleArrayInit(const InitializedEntity &Entity,
470 Expr *InitExpr, FieldDecl *Field,
471 bool TopLevelObject);
472 void CheckEmptyInitializable(const InitializedEntity &Entity,
473 SourceLocation Loc);
474
475 public:
476 InitListChecker(Sema &S, const InitializedEntity &Entity, InitListExpr *IL,
477 QualType &T, bool VerifyOnly, bool TreatUnavailableAsInvalid,
478 bool InOverloadResolution = false);
HadError()479 bool HadError() { return hadError; }
480
481 // Retrieves the fully-structured initializer list used for
482 // semantic analysis and code generation.
getFullyStructuredList() const483 InitListExpr *getFullyStructuredList() const { return FullyStructuredList; }
484 };
485
486 } // end anonymous namespace
487
PerformEmptyInit(SourceLocation Loc,const InitializedEntity & Entity)488 ExprResult InitListChecker::PerformEmptyInit(SourceLocation Loc,
489 const InitializedEntity &Entity) {
490 InitializationKind Kind = InitializationKind::CreateValue(Loc, Loc, Loc,
491 true);
492 MultiExprArg SubInit;
493 Expr *InitExpr;
494 InitListExpr DummyInitList(SemaRef.Context, Loc, None, Loc);
495
496 // C++ [dcl.init.aggr]p7:
497 // If there are fewer initializer-clauses in the list than there are
498 // members in the aggregate, then each member not explicitly initialized
499 // ...
500 bool EmptyInitList = SemaRef.getLangOpts().CPlusPlus11 &&
501 Entity.getType()->getBaseElementTypeUnsafe()->isRecordType();
502 if (EmptyInitList) {
503 // C++1y / DR1070:
504 // shall be initialized [...] from an empty initializer list.
505 //
506 // We apply the resolution of this DR to C++11 but not C++98, since C++98
507 // does not have useful semantics for initialization from an init list.
508 // We treat this as copy-initialization, because aggregate initialization
509 // always performs copy-initialization on its elements.
510 //
511 // Only do this if we're initializing a class type, to avoid filling in
512 // the initializer list where possible.
513 InitExpr = VerifyOnly ? &DummyInitList : new (SemaRef.Context)
514 InitListExpr(SemaRef.Context, Loc, None, Loc);
515 InitExpr->setType(SemaRef.Context.VoidTy);
516 SubInit = InitExpr;
517 Kind = InitializationKind::CreateCopy(Loc, Loc);
518 } else {
519 // C++03:
520 // shall be value-initialized.
521 }
522
523 InitializationSequence InitSeq(SemaRef, Entity, Kind, SubInit);
524 // libstdc++4.6 marks the vector default constructor as explicit in
525 // _GLIBCXX_DEBUG mode, so recover using the C++03 logic in that case.
526 // stlport does so too. Look for std::__debug for libstdc++, and for
527 // std:: for stlport. This is effectively a compiler-side implementation of
528 // LWG2193.
529 if (!InitSeq && EmptyInitList && InitSeq.getFailureKind() ==
530 InitializationSequence::FK_ExplicitConstructor) {
531 OverloadCandidateSet::iterator Best;
532 OverloadingResult O =
533 InitSeq.getFailedCandidateSet()
534 .BestViableFunction(SemaRef, Kind.getLocation(), Best);
535 (void)O;
536 assert(O == OR_Success && "Inconsistent overload resolution");
537 CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
538 CXXRecordDecl *R = CtorDecl->getParent();
539
540 if (CtorDecl->getMinRequiredArguments() == 0 &&
541 CtorDecl->isExplicit() && R->getDeclName() &&
542 SemaRef.SourceMgr.isInSystemHeader(CtorDecl->getLocation())) {
543 bool IsInStd = false;
544 for (NamespaceDecl *ND = dyn_cast<NamespaceDecl>(R->getDeclContext());
545 ND && !IsInStd; ND = dyn_cast<NamespaceDecl>(ND->getParent())) {
546 if (SemaRef.getStdNamespace()->InEnclosingNamespaceSetOf(ND))
547 IsInStd = true;
548 }
549
550 if (IsInStd && llvm::StringSwitch<bool>(R->getName())
551 .Cases("basic_string", "deque", "forward_list", true)
552 .Cases("list", "map", "multimap", "multiset", true)
553 .Cases("priority_queue", "queue", "set", "stack", true)
554 .Cases("unordered_map", "unordered_set", "vector", true)
555 .Default(false)) {
556 InitSeq.InitializeFrom(
557 SemaRef, Entity,
558 InitializationKind::CreateValue(Loc, Loc, Loc, true),
559 MultiExprArg(), /*TopLevelOfInitList=*/false,
560 TreatUnavailableAsInvalid);
561 // Emit a warning for this. System header warnings aren't shown
562 // by default, but people working on system headers should see it.
563 if (!VerifyOnly) {
564 SemaRef.Diag(CtorDecl->getLocation(),
565 diag::warn_invalid_initializer_from_system_header);
566 if (Entity.getKind() == InitializedEntity::EK_Member)
567 SemaRef.Diag(Entity.getDecl()->getLocation(),
568 diag::note_used_in_initialization_here);
569 else if (Entity.getKind() == InitializedEntity::EK_ArrayElement)
570 SemaRef.Diag(Loc, diag::note_used_in_initialization_here);
571 }
572 }
573 }
574 }
575 if (!InitSeq) {
576 if (!VerifyOnly) {
577 InitSeq.Diagnose(SemaRef, Entity, Kind, SubInit);
578 if (Entity.getKind() == InitializedEntity::EK_Member)
579 SemaRef.Diag(Entity.getDecl()->getLocation(),
580 diag::note_in_omitted_aggregate_initializer)
581 << /*field*/1 << Entity.getDecl();
582 else if (Entity.getKind() == InitializedEntity::EK_ArrayElement) {
583 bool IsTrailingArrayNewMember =
584 Entity.getParent() &&
585 Entity.getParent()->isVariableLengthArrayNew();
586 SemaRef.Diag(Loc, diag::note_in_omitted_aggregate_initializer)
587 << (IsTrailingArrayNewMember ? 2 : /*array element*/0)
588 << Entity.getElementIndex();
589 }
590 }
591 hadError = true;
592 return ExprError();
593 }
594
595 return VerifyOnly ? ExprResult()
596 : InitSeq.Perform(SemaRef, Entity, Kind, SubInit);
597 }
598
CheckEmptyInitializable(const InitializedEntity & Entity,SourceLocation Loc)599 void InitListChecker::CheckEmptyInitializable(const InitializedEntity &Entity,
600 SourceLocation Loc) {
601 // If we're building a fully-structured list, we'll check this at the end
602 // once we know which elements are actually initialized. Otherwise, we know
603 // that there are no designators so we can just check now.
604 if (FullyStructuredList)
605 return;
606 PerformEmptyInit(Loc, Entity);
607 }
608
FillInEmptyInitForBase(unsigned Init,const CXXBaseSpecifier & Base,const InitializedEntity & ParentEntity,InitListExpr * ILE,bool & RequiresSecondPass,bool FillWithNoInit)609 void InitListChecker::FillInEmptyInitForBase(
610 unsigned Init, const CXXBaseSpecifier &Base,
611 const InitializedEntity &ParentEntity, InitListExpr *ILE,
612 bool &RequiresSecondPass, bool FillWithNoInit) {
613 InitializedEntity BaseEntity = InitializedEntity::InitializeBase(
614 SemaRef.Context, &Base, false, &ParentEntity);
615
616 if (Init >= ILE->getNumInits() || !ILE->getInit(Init)) {
617 ExprResult BaseInit = FillWithNoInit
618 ? new (SemaRef.Context) NoInitExpr(Base.getType())
619 : PerformEmptyInit(ILE->getEndLoc(), BaseEntity);
620 if (BaseInit.isInvalid()) {
621 hadError = true;
622 return;
623 }
624
625 if (!VerifyOnly) {
626 assert(Init < ILE->getNumInits() && "should have been expanded");
627 ILE->setInit(Init, BaseInit.getAs<Expr>());
628 }
629 } else if (InitListExpr *InnerILE =
630 dyn_cast<InitListExpr>(ILE->getInit(Init))) {
631 FillInEmptyInitializations(BaseEntity, InnerILE, RequiresSecondPass,
632 ILE, Init, FillWithNoInit);
633 } else if (DesignatedInitUpdateExpr *InnerDIUE =
634 dyn_cast<DesignatedInitUpdateExpr>(ILE->getInit(Init))) {
635 FillInEmptyInitializations(BaseEntity, InnerDIUE->getUpdater(),
636 RequiresSecondPass, ILE, Init,
637 /*FillWithNoInit =*/true);
638 }
639 }
640
FillInEmptyInitForField(unsigned Init,FieldDecl * Field,const InitializedEntity & ParentEntity,InitListExpr * ILE,bool & RequiresSecondPass,bool FillWithNoInit)641 void InitListChecker::FillInEmptyInitForField(unsigned Init, FieldDecl *Field,
642 const InitializedEntity &ParentEntity,
643 InitListExpr *ILE,
644 bool &RequiresSecondPass,
645 bool FillWithNoInit) {
646 SourceLocation Loc = ILE->getEndLoc();
647 unsigned NumInits = ILE->getNumInits();
648 InitializedEntity MemberEntity
649 = InitializedEntity::InitializeMember(Field, &ParentEntity);
650
651 if (Init >= NumInits || !ILE->getInit(Init)) {
652 if (const RecordType *RType = ILE->getType()->getAs<RecordType>())
653 if (!RType->getDecl()->isUnion())
654 assert((Init < NumInits || VerifyOnly) &&
655 "This ILE should have been expanded");
656
657 if (FillWithNoInit) {
658 assert(!VerifyOnly && "should not fill with no-init in verify-only mode");
659 Expr *Filler = new (SemaRef.Context) NoInitExpr(Field->getType());
660 if (Init < NumInits)
661 ILE->setInit(Init, Filler);
662 else
663 ILE->updateInit(SemaRef.Context, Init, Filler);
664 return;
665 }
666 // C++1y [dcl.init.aggr]p7:
667 // If there are fewer initializer-clauses in the list than there are
668 // members in the aggregate, then each member not explicitly initialized
669 // shall be initialized from its brace-or-equal-initializer [...]
670 if (Field->hasInClassInitializer()) {
671 if (VerifyOnly)
672 return;
673
674 ExprResult DIE = SemaRef.BuildCXXDefaultInitExpr(Loc, Field);
675 if (DIE.isInvalid()) {
676 hadError = true;
677 return;
678 }
679 SemaRef.checkInitializerLifetime(MemberEntity, DIE.get());
680 if (Init < NumInits)
681 ILE->setInit(Init, DIE.get());
682 else {
683 ILE->updateInit(SemaRef.Context, Init, DIE.get());
684 RequiresSecondPass = true;
685 }
686 return;
687 }
688
689 if (Field->getType()->isReferenceType()) {
690 if (!VerifyOnly) {
691 // C++ [dcl.init.aggr]p9:
692 // If an incomplete or empty initializer-list leaves a
693 // member of reference type uninitialized, the program is
694 // ill-formed.
695 SemaRef.Diag(Loc, diag::err_init_reference_member_uninitialized)
696 << Field->getType()
697 << ILE->getSyntacticForm()->getSourceRange();
698 SemaRef.Diag(Field->getLocation(),
699 diag::note_uninit_reference_member);
700 }
701 hadError = true;
702 return;
703 }
704
705 ExprResult MemberInit = PerformEmptyInit(Loc, MemberEntity);
706 if (MemberInit.isInvalid()) {
707 hadError = true;
708 return;
709 }
710
711 if (hadError || VerifyOnly) {
712 // Do nothing
713 } else if (Init < NumInits) {
714 ILE->setInit(Init, MemberInit.getAs<Expr>());
715 } else if (!isa<ImplicitValueInitExpr>(MemberInit.get())) {
716 // Empty initialization requires a constructor call, so
717 // extend the initializer list to include the constructor
718 // call and make a note that we'll need to take another pass
719 // through the initializer list.
720 ILE->updateInit(SemaRef.Context, Init, MemberInit.getAs<Expr>());
721 RequiresSecondPass = true;
722 }
723 } else if (InitListExpr *InnerILE
724 = dyn_cast<InitListExpr>(ILE->getInit(Init))) {
725 FillInEmptyInitializations(MemberEntity, InnerILE,
726 RequiresSecondPass, ILE, Init, FillWithNoInit);
727 } else if (DesignatedInitUpdateExpr *InnerDIUE =
728 dyn_cast<DesignatedInitUpdateExpr>(ILE->getInit(Init))) {
729 FillInEmptyInitializations(MemberEntity, InnerDIUE->getUpdater(),
730 RequiresSecondPass, ILE, Init,
731 /*FillWithNoInit =*/true);
732 }
733 }
734
735 /// Recursively replaces NULL values within the given initializer list
736 /// with expressions that perform value-initialization of the
737 /// appropriate type, and finish off the InitListExpr formation.
738 void
FillInEmptyInitializations(const InitializedEntity & Entity,InitListExpr * ILE,bool & RequiresSecondPass,InitListExpr * OuterILE,unsigned OuterIndex,bool FillWithNoInit)739 InitListChecker::FillInEmptyInitializations(const InitializedEntity &Entity,
740 InitListExpr *ILE,
741 bool &RequiresSecondPass,
742 InitListExpr *OuterILE,
743 unsigned OuterIndex,
744 bool FillWithNoInit) {
745 assert((ILE->getType() != SemaRef.Context.VoidTy) &&
746 "Should not have void type");
747
748 // We don't need to do any checks when just filling NoInitExprs; that can't
749 // fail.
750 if (FillWithNoInit && VerifyOnly)
751 return;
752
753 // If this is a nested initializer list, we might have changed its contents
754 // (and therefore some of its properties, such as instantiation-dependence)
755 // while filling it in. Inform the outer initializer list so that its state
756 // can be updated to match.
757 // FIXME: We should fully build the inner initializers before constructing
758 // the outer InitListExpr instead of mutating AST nodes after they have
759 // been used as subexpressions of other nodes.
760 struct UpdateOuterILEWithUpdatedInit {
761 InitListExpr *Outer;
762 unsigned OuterIndex;
763 ~UpdateOuterILEWithUpdatedInit() {
764 if (Outer)
765 Outer->setInit(OuterIndex, Outer->getInit(OuterIndex));
766 }
767 } UpdateOuterRAII = {OuterILE, OuterIndex};
768
769 // A transparent ILE is not performing aggregate initialization and should
770 // not be filled in.
771 if (ILE->isTransparent())
772 return;
773
774 if (const RecordType *RType = ILE->getType()->getAs<RecordType>()) {
775 const RecordDecl *RDecl = RType->getDecl();
776 if (RDecl->isUnion() && ILE->getInitializedFieldInUnion())
777 FillInEmptyInitForField(0, ILE->getInitializedFieldInUnion(),
778 Entity, ILE, RequiresSecondPass, FillWithNoInit);
779 else if (RDecl->isUnion() && isa<CXXRecordDecl>(RDecl) &&
780 cast<CXXRecordDecl>(RDecl)->hasInClassInitializer()) {
781 for (auto *Field : RDecl->fields()) {
782 if (Field->hasInClassInitializer()) {
783 FillInEmptyInitForField(0, Field, Entity, ILE, RequiresSecondPass,
784 FillWithNoInit);
785 break;
786 }
787 }
788 } else {
789 // The fields beyond ILE->getNumInits() are default initialized, so in
790 // order to leave them uninitialized, the ILE is expanded and the extra
791 // fields are then filled with NoInitExpr.
792 unsigned NumElems = numStructUnionElements(ILE->getType());
793 if (RDecl->hasFlexibleArrayMember())
794 ++NumElems;
795 if (!VerifyOnly && ILE->getNumInits() < NumElems)
796 ILE->resizeInits(SemaRef.Context, NumElems);
797
798 unsigned Init = 0;
799
800 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RDecl)) {
801 for (auto &Base : CXXRD->bases()) {
802 if (hadError)
803 return;
804
805 FillInEmptyInitForBase(Init, Base, Entity, ILE, RequiresSecondPass,
806 FillWithNoInit);
807 ++Init;
808 }
809 }
810
811 for (auto *Field : RDecl->fields()) {
812 if (Field->isUnnamedBitfield())
813 continue;
814
815 if (hadError)
816 return;
817
818 FillInEmptyInitForField(Init, Field, Entity, ILE, RequiresSecondPass,
819 FillWithNoInit);
820 if (hadError)
821 return;
822
823 ++Init;
824
825 // Only look at the first initialization of a union.
826 if (RDecl->isUnion())
827 break;
828 }
829 }
830
831 return;
832 }
833
834 QualType ElementType;
835
836 InitializedEntity ElementEntity = Entity;
837 unsigned NumInits = ILE->getNumInits();
838 unsigned NumElements = NumInits;
839 if (const ArrayType *AType = SemaRef.Context.getAsArrayType(ILE->getType())) {
840 ElementType = AType->getElementType();
841 if (const auto *CAType = dyn_cast<ConstantArrayType>(AType))
842 NumElements = CAType->getSize().getZExtValue();
843 // For an array new with an unknown bound, ask for one additional element
844 // in order to populate the array filler.
845 if (Entity.isVariableLengthArrayNew())
846 ++NumElements;
847 ElementEntity = InitializedEntity::InitializeElement(SemaRef.Context,
848 0, Entity);
849 } else if (const VectorType *VType = ILE->getType()->getAs<VectorType>()) {
850 ElementType = VType->getElementType();
851 NumElements = VType->getNumElements();
852 ElementEntity = InitializedEntity::InitializeElement(SemaRef.Context,
853 0, Entity);
854 } else
855 ElementType = ILE->getType();
856
857 bool SkipEmptyInitChecks = false;
858 for (unsigned Init = 0; Init != NumElements; ++Init) {
859 if (hadError)
860 return;
861
862 if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement ||
863 ElementEntity.getKind() == InitializedEntity::EK_VectorElement)
864 ElementEntity.setElementIndex(Init);
865
866 if (Init >= NumInits && (ILE->hasArrayFiller() || SkipEmptyInitChecks))
867 return;
868
869 Expr *InitExpr = (Init < NumInits ? ILE->getInit(Init) : nullptr);
870 if (!InitExpr && Init < NumInits && ILE->hasArrayFiller())
871 ILE->setInit(Init, ILE->getArrayFiller());
872 else if (!InitExpr && !ILE->hasArrayFiller()) {
873 // In VerifyOnly mode, there's no point performing empty initialization
874 // more than once.
875 if (SkipEmptyInitChecks)
876 continue;
877
878 Expr *Filler = nullptr;
879
880 if (FillWithNoInit)
881 Filler = new (SemaRef.Context) NoInitExpr(ElementType);
882 else {
883 ExprResult ElementInit =
884 PerformEmptyInit(ILE->getEndLoc(), ElementEntity);
885 if (ElementInit.isInvalid()) {
886 hadError = true;
887 return;
888 }
889
890 Filler = ElementInit.getAs<Expr>();
891 }
892
893 if (hadError) {
894 // Do nothing
895 } else if (VerifyOnly) {
896 SkipEmptyInitChecks = true;
897 } else if (Init < NumInits) {
898 // For arrays, just set the expression used for value-initialization
899 // of the "holes" in the array.
900 if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement)
901 ILE->setArrayFiller(Filler);
902 else
903 ILE->setInit(Init, Filler);
904 } else {
905 // For arrays, just set the expression used for value-initialization
906 // of the rest of elements and exit.
907 if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement) {
908 ILE->setArrayFiller(Filler);
909 return;
910 }
911
912 if (!isa<ImplicitValueInitExpr>(Filler) && !isa<NoInitExpr>(Filler)) {
913 // Empty initialization requires a constructor call, so
914 // extend the initializer list to include the constructor
915 // call and make a note that we'll need to take another pass
916 // through the initializer list.
917 ILE->updateInit(SemaRef.Context, Init, Filler);
918 RequiresSecondPass = true;
919 }
920 }
921 } else if (InitListExpr *InnerILE
922 = dyn_cast_or_null<InitListExpr>(InitExpr)) {
923 FillInEmptyInitializations(ElementEntity, InnerILE, RequiresSecondPass,
924 ILE, Init, FillWithNoInit);
925 } else if (DesignatedInitUpdateExpr *InnerDIUE =
926 dyn_cast_or_null<DesignatedInitUpdateExpr>(InitExpr)) {
927 FillInEmptyInitializations(ElementEntity, InnerDIUE->getUpdater(),
928 RequiresSecondPass, ILE, Init,
929 /*FillWithNoInit =*/true);
930 }
931 }
932 }
933
hasAnyDesignatedInits(const InitListExpr * IL)934 static bool hasAnyDesignatedInits(const InitListExpr *IL) {
935 for (const Stmt *Init : *IL)
936 if (Init && isa<DesignatedInitExpr>(Init))
937 return true;
938 return false;
939 }
940
InitListChecker(Sema & S,const InitializedEntity & Entity,InitListExpr * IL,QualType & T,bool VerifyOnly,bool TreatUnavailableAsInvalid,bool InOverloadResolution)941 InitListChecker::InitListChecker(Sema &S, const InitializedEntity &Entity,
942 InitListExpr *IL, QualType &T, bool VerifyOnly,
943 bool TreatUnavailableAsInvalid,
944 bool InOverloadResolution)
945 : SemaRef(S), VerifyOnly(VerifyOnly),
946 TreatUnavailableAsInvalid(TreatUnavailableAsInvalid),
947 InOverloadResolution(InOverloadResolution) {
948 if (!VerifyOnly || hasAnyDesignatedInits(IL)) {
949 FullyStructuredList =
950 createInitListExpr(T, IL->getSourceRange(), IL->getNumInits());
951
952 // FIXME: Check that IL isn't already the semantic form of some other
953 // InitListExpr. If it is, we'd create a broken AST.
954 if (!VerifyOnly)
955 FullyStructuredList->setSyntacticForm(IL);
956 }
957
958 CheckExplicitInitList(Entity, IL, T, FullyStructuredList,
959 /*TopLevelObject=*/true);
960
961 if (!hadError && FullyStructuredList) {
962 bool RequiresSecondPass = false;
963 FillInEmptyInitializations(Entity, FullyStructuredList, RequiresSecondPass,
964 /*OuterILE=*/nullptr, /*OuterIndex=*/0);
965 if (RequiresSecondPass && !hadError)
966 FillInEmptyInitializations(Entity, FullyStructuredList,
967 RequiresSecondPass, nullptr, 0);
968 }
969 if (hadError && FullyStructuredList)
970 FullyStructuredList->markError();
971 }
972
numArrayElements(QualType DeclType)973 int InitListChecker::numArrayElements(QualType DeclType) {
974 // FIXME: use a proper constant
975 int maxElements = 0x7FFFFFFF;
976 if (const ConstantArrayType *CAT =
977 SemaRef.Context.getAsConstantArrayType(DeclType)) {
978 maxElements = static_cast<int>(CAT->getSize().getZExtValue());
979 }
980 return maxElements;
981 }
982
numStructUnionElements(QualType DeclType)983 int InitListChecker::numStructUnionElements(QualType DeclType) {
984 RecordDecl *structDecl = DeclType->castAs<RecordType>()->getDecl();
985 int InitializableMembers = 0;
986 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(structDecl))
987 InitializableMembers += CXXRD->getNumBases();
988 for (const auto *Field : structDecl->fields())
989 if (!Field->isUnnamedBitfield())
990 ++InitializableMembers;
991
992 if (structDecl->isUnion())
993 return std::min(InitializableMembers, 1);
994 return InitializableMembers - structDecl->hasFlexibleArrayMember();
995 }
996
997 /// Determine whether Entity is an entity for which it is idiomatic to elide
998 /// the braces in aggregate initialization.
isIdiomaticBraceElisionEntity(const InitializedEntity & Entity)999 static bool isIdiomaticBraceElisionEntity(const InitializedEntity &Entity) {
1000 // Recursive initialization of the one and only field within an aggregate
1001 // class is considered idiomatic. This case arises in particular for
1002 // initialization of std::array, where the C++ standard suggests the idiom of
1003 //
1004 // std::array<T, N> arr = {1, 2, 3};
1005 //
1006 // (where std::array is an aggregate struct containing a single array field.
1007
1008 // FIXME: Should aggregate initialization of a struct with a single
1009 // base class and no members also suppress the warning?
1010 if (Entity.getKind() != InitializedEntity::EK_Member || !Entity.getParent())
1011 return false;
1012
1013 auto *ParentRD =
1014 Entity.getParent()->getType()->castAs<RecordType>()->getDecl();
1015 if (CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(ParentRD))
1016 if (CXXRD->getNumBases())
1017 return false;
1018
1019 auto FieldIt = ParentRD->field_begin();
1020 assert(FieldIt != ParentRD->field_end() &&
1021 "no fields but have initializer for member?");
1022 return ++FieldIt == ParentRD->field_end();
1023 }
1024
1025 /// Check whether the range of the initializer \p ParentIList from element
1026 /// \p Index onwards can be used to initialize an object of type \p T. Update
1027 /// \p Index to indicate how many elements of the list were consumed.
1028 ///
1029 /// This also fills in \p StructuredList, from element \p StructuredIndex
1030 /// onwards, with the fully-braced, desugared form of the initialization.
CheckImplicitInitList(const InitializedEntity & Entity,InitListExpr * ParentIList,QualType T,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1031 void InitListChecker::CheckImplicitInitList(const InitializedEntity &Entity,
1032 InitListExpr *ParentIList,
1033 QualType T, unsigned &Index,
1034 InitListExpr *StructuredList,
1035 unsigned &StructuredIndex) {
1036 int maxElements = 0;
1037
1038 if (T->isArrayType())
1039 maxElements = numArrayElements(T);
1040 else if (T->isRecordType())
1041 maxElements = numStructUnionElements(T);
1042 else if (T->isVectorType())
1043 maxElements = T->castAs<VectorType>()->getNumElements();
1044 else
1045 llvm_unreachable("CheckImplicitInitList(): Illegal type");
1046
1047 if (maxElements == 0) {
1048 if (!VerifyOnly)
1049 SemaRef.Diag(ParentIList->getInit(Index)->getBeginLoc(),
1050 diag::err_implicit_empty_initializer);
1051 ++Index;
1052 hadError = true;
1053 return;
1054 }
1055
1056 // Build a structured initializer list corresponding to this subobject.
1057 InitListExpr *StructuredSubobjectInitList = getStructuredSubobjectInit(
1058 ParentIList, Index, T, StructuredList, StructuredIndex,
1059 SourceRange(ParentIList->getInit(Index)->getBeginLoc(),
1060 ParentIList->getSourceRange().getEnd()));
1061 unsigned StructuredSubobjectInitIndex = 0;
1062
1063 // Check the element types and build the structural subobject.
1064 unsigned StartIndex = Index;
1065 CheckListElementTypes(Entity, ParentIList, T,
1066 /*SubobjectIsDesignatorContext=*/false, Index,
1067 StructuredSubobjectInitList,
1068 StructuredSubobjectInitIndex);
1069
1070 if (StructuredSubobjectInitList) {
1071 StructuredSubobjectInitList->setType(T);
1072
1073 unsigned EndIndex = (Index == StartIndex? StartIndex : Index - 1);
1074 // Update the structured sub-object initializer so that it's ending
1075 // range corresponds with the end of the last initializer it used.
1076 if (EndIndex < ParentIList->getNumInits() &&
1077 ParentIList->getInit(EndIndex)) {
1078 SourceLocation EndLoc
1079 = ParentIList->getInit(EndIndex)->getSourceRange().getEnd();
1080 StructuredSubobjectInitList->setRBraceLoc(EndLoc);
1081 }
1082
1083 // Complain about missing braces.
1084 if (!VerifyOnly && (T->isArrayType() || T->isRecordType()) &&
1085 !ParentIList->isIdiomaticZeroInitializer(SemaRef.getLangOpts()) &&
1086 !isIdiomaticBraceElisionEntity(Entity)) {
1087 SemaRef.Diag(StructuredSubobjectInitList->getBeginLoc(),
1088 diag::warn_missing_braces)
1089 << StructuredSubobjectInitList->getSourceRange()
1090 << FixItHint::CreateInsertion(
1091 StructuredSubobjectInitList->getBeginLoc(), "{")
1092 << FixItHint::CreateInsertion(
1093 SemaRef.getLocForEndOfToken(
1094 StructuredSubobjectInitList->getEndLoc()),
1095 "}");
1096 }
1097
1098 // Warn if this type won't be an aggregate in future versions of C++.
1099 auto *CXXRD = T->getAsCXXRecordDecl();
1100 if (!VerifyOnly && CXXRD && CXXRD->hasUserDeclaredConstructor()) {
1101 SemaRef.Diag(StructuredSubobjectInitList->getBeginLoc(),
1102 diag::warn_cxx20_compat_aggregate_init_with_ctors)
1103 << StructuredSubobjectInitList->getSourceRange() << T;
1104 }
1105 }
1106 }
1107
1108 /// Warn that \p Entity was of scalar type and was initialized by a
1109 /// single-element braced initializer list.
warnBracedScalarInit(Sema & S,const InitializedEntity & Entity,SourceRange Braces)1110 static void warnBracedScalarInit(Sema &S, const InitializedEntity &Entity,
1111 SourceRange Braces) {
1112 // Don't warn during template instantiation. If the initialization was
1113 // non-dependent, we warned during the initial parse; otherwise, the
1114 // type might not be scalar in some uses of the template.
1115 if (S.inTemplateInstantiation())
1116 return;
1117
1118 unsigned DiagID = 0;
1119
1120 switch (Entity.getKind()) {
1121 case InitializedEntity::EK_VectorElement:
1122 case InitializedEntity::EK_ComplexElement:
1123 case InitializedEntity::EK_ArrayElement:
1124 case InitializedEntity::EK_Parameter:
1125 case InitializedEntity::EK_Parameter_CF_Audited:
1126 case InitializedEntity::EK_TemplateParameter:
1127 case InitializedEntity::EK_Result:
1128 // Extra braces here are suspicious.
1129 DiagID = diag::warn_braces_around_init;
1130 break;
1131
1132 case InitializedEntity::EK_Member:
1133 // Warn on aggregate initialization but not on ctor init list or
1134 // default member initializer.
1135 if (Entity.getParent())
1136 DiagID = diag::warn_braces_around_init;
1137 break;
1138
1139 case InitializedEntity::EK_Variable:
1140 case InitializedEntity::EK_LambdaCapture:
1141 // No warning, might be direct-list-initialization.
1142 // FIXME: Should we warn for copy-list-initialization in these cases?
1143 break;
1144
1145 case InitializedEntity::EK_New:
1146 case InitializedEntity::EK_Temporary:
1147 case InitializedEntity::EK_CompoundLiteralInit:
1148 // No warning, braces are part of the syntax of the underlying construct.
1149 break;
1150
1151 case InitializedEntity::EK_RelatedResult:
1152 // No warning, we already warned when initializing the result.
1153 break;
1154
1155 case InitializedEntity::EK_Exception:
1156 case InitializedEntity::EK_Base:
1157 case InitializedEntity::EK_Delegating:
1158 case InitializedEntity::EK_BlockElement:
1159 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
1160 case InitializedEntity::EK_Binding:
1161 case InitializedEntity::EK_StmtExprResult:
1162 llvm_unreachable("unexpected braced scalar init");
1163 }
1164
1165 if (DiagID) {
1166 S.Diag(Braces.getBegin(), DiagID)
1167 << Entity.getType()->isSizelessBuiltinType() << Braces
1168 << FixItHint::CreateRemoval(Braces.getBegin())
1169 << FixItHint::CreateRemoval(Braces.getEnd());
1170 }
1171 }
1172
1173 /// Check whether the initializer \p IList (that was written with explicit
1174 /// braces) can be used to initialize an object of type \p T.
1175 ///
1176 /// This also fills in \p StructuredList with the fully-braced, desugared
1177 /// form of the initialization.
CheckExplicitInitList(const InitializedEntity & Entity,InitListExpr * IList,QualType & T,InitListExpr * StructuredList,bool TopLevelObject)1178 void InitListChecker::CheckExplicitInitList(const InitializedEntity &Entity,
1179 InitListExpr *IList, QualType &T,
1180 InitListExpr *StructuredList,
1181 bool TopLevelObject) {
1182 unsigned Index = 0, StructuredIndex = 0;
1183 CheckListElementTypes(Entity, IList, T, /*SubobjectIsDesignatorContext=*/true,
1184 Index, StructuredList, StructuredIndex, TopLevelObject);
1185 if (StructuredList) {
1186 QualType ExprTy = T;
1187 if (!ExprTy->isArrayType())
1188 ExprTy = ExprTy.getNonLValueExprType(SemaRef.Context);
1189 if (!VerifyOnly)
1190 IList->setType(ExprTy);
1191 StructuredList->setType(ExprTy);
1192 }
1193 if (hadError)
1194 return;
1195
1196 // Don't complain for incomplete types, since we'll get an error elsewhere.
1197 if (Index < IList->getNumInits() && !T->isIncompleteType()) {
1198 // We have leftover initializers
1199 bool ExtraInitsIsError = SemaRef.getLangOpts().CPlusPlus ||
1200 (SemaRef.getLangOpts().OpenCL && T->isVectorType());
1201 hadError = ExtraInitsIsError;
1202 if (VerifyOnly) {
1203 return;
1204 } else if (StructuredIndex == 1 &&
1205 IsStringInit(StructuredList->getInit(0), T, SemaRef.Context) ==
1206 SIF_None) {
1207 unsigned DK =
1208 ExtraInitsIsError
1209 ? diag::err_excess_initializers_in_char_array_initializer
1210 : diag::ext_excess_initializers_in_char_array_initializer;
1211 SemaRef.Diag(IList->getInit(Index)->getBeginLoc(), DK)
1212 << IList->getInit(Index)->getSourceRange();
1213 } else if (T->isSizelessBuiltinType()) {
1214 unsigned DK = ExtraInitsIsError
1215 ? diag::err_excess_initializers_for_sizeless_type
1216 : diag::ext_excess_initializers_for_sizeless_type;
1217 SemaRef.Diag(IList->getInit(Index)->getBeginLoc(), DK)
1218 << T << IList->getInit(Index)->getSourceRange();
1219 } else {
1220 int initKind = T->isArrayType() ? 0 :
1221 T->isVectorType() ? 1 :
1222 T->isScalarType() ? 2 :
1223 T->isUnionType() ? 3 :
1224 4;
1225
1226 unsigned DK = ExtraInitsIsError ? diag::err_excess_initializers
1227 : diag::ext_excess_initializers;
1228 SemaRef.Diag(IList->getInit(Index)->getBeginLoc(), DK)
1229 << initKind << IList->getInit(Index)->getSourceRange();
1230 }
1231 }
1232
1233 if (!VerifyOnly) {
1234 if (T->isScalarType() && IList->getNumInits() == 1 &&
1235 !isa<InitListExpr>(IList->getInit(0)))
1236 warnBracedScalarInit(SemaRef, Entity, IList->getSourceRange());
1237
1238 // Warn if this is a class type that won't be an aggregate in future
1239 // versions of C++.
1240 auto *CXXRD = T->getAsCXXRecordDecl();
1241 if (CXXRD && CXXRD->hasUserDeclaredConstructor()) {
1242 // Don't warn if there's an equivalent default constructor that would be
1243 // used instead.
1244 bool HasEquivCtor = false;
1245 if (IList->getNumInits() == 0) {
1246 auto *CD = SemaRef.LookupDefaultConstructor(CXXRD);
1247 HasEquivCtor = CD && !CD->isDeleted();
1248 }
1249
1250 if (!HasEquivCtor) {
1251 SemaRef.Diag(IList->getBeginLoc(),
1252 diag::warn_cxx20_compat_aggregate_init_with_ctors)
1253 << IList->getSourceRange() << T;
1254 }
1255 }
1256 }
1257 }
1258
CheckListElementTypes(const InitializedEntity & Entity,InitListExpr * IList,QualType & DeclType,bool SubobjectIsDesignatorContext,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex,bool TopLevelObject)1259 void InitListChecker::CheckListElementTypes(const InitializedEntity &Entity,
1260 InitListExpr *IList,
1261 QualType &DeclType,
1262 bool SubobjectIsDesignatorContext,
1263 unsigned &Index,
1264 InitListExpr *StructuredList,
1265 unsigned &StructuredIndex,
1266 bool TopLevelObject) {
1267 if (DeclType->isAnyComplexType() && SubobjectIsDesignatorContext) {
1268 // Explicitly braced initializer for complex type can be real+imaginary
1269 // parts.
1270 CheckComplexType(Entity, IList, DeclType, Index,
1271 StructuredList, StructuredIndex);
1272 } else if (DeclType->isScalarType()) {
1273 CheckScalarType(Entity, IList, DeclType, Index,
1274 StructuredList, StructuredIndex);
1275 } else if (DeclType->isVectorType()) {
1276 CheckVectorType(Entity, IList, DeclType, Index,
1277 StructuredList, StructuredIndex);
1278 } else if (DeclType->isRecordType()) {
1279 assert(DeclType->isAggregateType() &&
1280 "non-aggregate records should be handed in CheckSubElementType");
1281 RecordDecl *RD = DeclType->castAs<RecordType>()->getDecl();
1282 auto Bases =
1283 CXXRecordDecl::base_class_range(CXXRecordDecl::base_class_iterator(),
1284 CXXRecordDecl::base_class_iterator());
1285 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
1286 Bases = CXXRD->bases();
1287 CheckStructUnionTypes(Entity, IList, DeclType, Bases, RD->field_begin(),
1288 SubobjectIsDesignatorContext, Index, StructuredList,
1289 StructuredIndex, TopLevelObject);
1290 } else if (DeclType->isArrayType()) {
1291 llvm::APSInt Zero(
1292 SemaRef.Context.getTypeSize(SemaRef.Context.getSizeType()),
1293 false);
1294 CheckArrayType(Entity, IList, DeclType, Zero,
1295 SubobjectIsDesignatorContext, Index,
1296 StructuredList, StructuredIndex);
1297 } else if (DeclType->isVoidType() || DeclType->isFunctionType()) {
1298 // This type is invalid, issue a diagnostic.
1299 ++Index;
1300 if (!VerifyOnly)
1301 SemaRef.Diag(IList->getBeginLoc(), diag::err_illegal_initializer_type)
1302 << DeclType;
1303 hadError = true;
1304 } else if (DeclType->isReferenceType()) {
1305 CheckReferenceType(Entity, IList, DeclType, Index,
1306 StructuredList, StructuredIndex);
1307 } else if (DeclType->isObjCObjectType()) {
1308 if (!VerifyOnly)
1309 SemaRef.Diag(IList->getBeginLoc(), diag::err_init_objc_class) << DeclType;
1310 hadError = true;
1311 } else if (DeclType->isOCLIntelSubgroupAVCType() ||
1312 DeclType->isSizelessBuiltinType()) {
1313 // Checks for scalar type are sufficient for these types too.
1314 CheckScalarType(Entity, IList, DeclType, Index, StructuredList,
1315 StructuredIndex);
1316 } else {
1317 if (!VerifyOnly)
1318 SemaRef.Diag(IList->getBeginLoc(), diag::err_illegal_initializer_type)
1319 << DeclType;
1320 hadError = true;
1321 }
1322 }
1323
CheckSubElementType(const InitializedEntity & Entity,InitListExpr * IList,QualType ElemType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1324 void InitListChecker::CheckSubElementType(const InitializedEntity &Entity,
1325 InitListExpr *IList,
1326 QualType ElemType,
1327 unsigned &Index,
1328 InitListExpr *StructuredList,
1329 unsigned &StructuredIndex) {
1330 Expr *expr = IList->getInit(Index);
1331
1332 if (ElemType->isReferenceType())
1333 return CheckReferenceType(Entity, IList, ElemType, Index,
1334 StructuredList, StructuredIndex);
1335
1336 if (InitListExpr *SubInitList = dyn_cast<InitListExpr>(expr)) {
1337 if (SubInitList->getNumInits() == 1 &&
1338 IsStringInit(SubInitList->getInit(0), ElemType, SemaRef.Context) ==
1339 SIF_None) {
1340 // FIXME: It would be more faithful and no less correct to include an
1341 // InitListExpr in the semantic form of the initializer list in this case.
1342 expr = SubInitList->getInit(0);
1343 }
1344 // Nested aggregate initialization and C++ initialization are handled later.
1345 } else if (isa<ImplicitValueInitExpr>(expr)) {
1346 // This happens during template instantiation when we see an InitListExpr
1347 // that we've already checked once.
1348 assert(SemaRef.Context.hasSameType(expr->getType(), ElemType) &&
1349 "found implicit initialization for the wrong type");
1350 UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
1351 ++Index;
1352 return;
1353 }
1354
1355 if (SemaRef.getLangOpts().CPlusPlus || isa<InitListExpr>(expr)) {
1356 // C++ [dcl.init.aggr]p2:
1357 // Each member is copy-initialized from the corresponding
1358 // initializer-clause.
1359
1360 // FIXME: Better EqualLoc?
1361 InitializationKind Kind =
1362 InitializationKind::CreateCopy(expr->getBeginLoc(), SourceLocation());
1363
1364 // Vector elements can be initialized from other vectors in which case
1365 // we need initialization entity with a type of a vector (and not a vector
1366 // element!) initializing multiple vector elements.
1367 auto TmpEntity =
1368 (ElemType->isExtVectorType() && !Entity.getType()->isExtVectorType())
1369 ? InitializedEntity::InitializeTemporary(ElemType)
1370 : Entity;
1371
1372 InitializationSequence Seq(SemaRef, TmpEntity, Kind, expr,
1373 /*TopLevelOfInitList*/ true);
1374
1375 // C++14 [dcl.init.aggr]p13:
1376 // If the assignment-expression can initialize a member, the member is
1377 // initialized. Otherwise [...] brace elision is assumed
1378 //
1379 // Brace elision is never performed if the element is not an
1380 // assignment-expression.
1381 if (Seq || isa<InitListExpr>(expr)) {
1382 if (!VerifyOnly) {
1383 ExprResult Result = Seq.Perform(SemaRef, TmpEntity, Kind, expr);
1384 if (Result.isInvalid())
1385 hadError = true;
1386
1387 UpdateStructuredListElement(StructuredList, StructuredIndex,
1388 Result.getAs<Expr>());
1389 } else if (!Seq) {
1390 hadError = true;
1391 } else if (StructuredList) {
1392 UpdateStructuredListElement(StructuredList, StructuredIndex,
1393 getDummyInit());
1394 }
1395 ++Index;
1396 return;
1397 }
1398
1399 // Fall through for subaggregate initialization
1400 } else if (ElemType->isScalarType() || ElemType->isAtomicType()) {
1401 // FIXME: Need to handle atomic aggregate types with implicit init lists.
1402 return CheckScalarType(Entity, IList, ElemType, Index,
1403 StructuredList, StructuredIndex);
1404 } else if (const ArrayType *arrayType =
1405 SemaRef.Context.getAsArrayType(ElemType)) {
1406 // arrayType can be incomplete if we're initializing a flexible
1407 // array member. There's nothing we can do with the completed
1408 // type here, though.
1409
1410 if (IsStringInit(expr, arrayType, SemaRef.Context) == SIF_None) {
1411 // FIXME: Should we do this checking in verify-only mode?
1412 if (!VerifyOnly)
1413 CheckStringInit(expr, ElemType, arrayType, SemaRef);
1414 if (StructuredList)
1415 UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
1416 ++Index;
1417 return;
1418 }
1419
1420 // Fall through for subaggregate initialization.
1421
1422 } else {
1423 assert((ElemType->isRecordType() || ElemType->isVectorType() ||
1424 ElemType->isOpenCLSpecificType()) && "Unexpected type");
1425
1426 // C99 6.7.8p13:
1427 //
1428 // The initializer for a structure or union object that has
1429 // automatic storage duration shall be either an initializer
1430 // list as described below, or a single expression that has
1431 // compatible structure or union type. In the latter case, the
1432 // initial value of the object, including unnamed members, is
1433 // that of the expression.
1434 ExprResult ExprRes = expr;
1435 if (SemaRef.CheckSingleAssignmentConstraints(
1436 ElemType, ExprRes, !VerifyOnly) != Sema::Incompatible) {
1437 if (ExprRes.isInvalid())
1438 hadError = true;
1439 else {
1440 ExprRes = SemaRef.DefaultFunctionArrayLvalueConversion(ExprRes.get());
1441 if (ExprRes.isInvalid())
1442 hadError = true;
1443 }
1444 UpdateStructuredListElement(StructuredList, StructuredIndex,
1445 ExprRes.getAs<Expr>());
1446 ++Index;
1447 return;
1448 }
1449 ExprRes.get();
1450 // Fall through for subaggregate initialization
1451 }
1452
1453 // C++ [dcl.init.aggr]p12:
1454 //
1455 // [...] Otherwise, if the member is itself a non-empty
1456 // subaggregate, brace elision is assumed and the initializer is
1457 // considered for the initialization of the first member of
1458 // the subaggregate.
1459 // OpenCL vector initializer is handled elsewhere.
1460 if ((!SemaRef.getLangOpts().OpenCL && ElemType->isVectorType()) ||
1461 ElemType->isAggregateType()) {
1462 CheckImplicitInitList(Entity, IList, ElemType, Index, StructuredList,
1463 StructuredIndex);
1464 ++StructuredIndex;
1465 } else {
1466 if (!VerifyOnly) {
1467 // We cannot initialize this element, so let PerformCopyInitialization
1468 // produce the appropriate diagnostic. We already checked that this
1469 // initialization will fail.
1470 ExprResult Copy =
1471 SemaRef.PerformCopyInitialization(Entity, SourceLocation(), expr,
1472 /*TopLevelOfInitList=*/true);
1473 (void)Copy;
1474 assert(Copy.isInvalid() &&
1475 "expected non-aggregate initialization to fail");
1476 }
1477 hadError = true;
1478 ++Index;
1479 ++StructuredIndex;
1480 }
1481 }
1482
CheckComplexType(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1483 void InitListChecker::CheckComplexType(const InitializedEntity &Entity,
1484 InitListExpr *IList, QualType DeclType,
1485 unsigned &Index,
1486 InitListExpr *StructuredList,
1487 unsigned &StructuredIndex) {
1488 assert(Index == 0 && "Index in explicit init list must be zero");
1489
1490 // As an extension, clang supports complex initializers, which initialize
1491 // a complex number component-wise. When an explicit initializer list for
1492 // a complex number contains two two initializers, this extension kicks in:
1493 // it exepcts the initializer list to contain two elements convertible to
1494 // the element type of the complex type. The first element initializes
1495 // the real part, and the second element intitializes the imaginary part.
1496
1497 if (IList->getNumInits() != 2)
1498 return CheckScalarType(Entity, IList, DeclType, Index, StructuredList,
1499 StructuredIndex);
1500
1501 // This is an extension in C. (The builtin _Complex type does not exist
1502 // in the C++ standard.)
1503 if (!SemaRef.getLangOpts().CPlusPlus && !VerifyOnly)
1504 SemaRef.Diag(IList->getBeginLoc(), diag::ext_complex_component_init)
1505 << IList->getSourceRange();
1506
1507 // Initialize the complex number.
1508 QualType elementType = DeclType->castAs<ComplexType>()->getElementType();
1509 InitializedEntity ElementEntity =
1510 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
1511
1512 for (unsigned i = 0; i < 2; ++i) {
1513 ElementEntity.setElementIndex(Index);
1514 CheckSubElementType(ElementEntity, IList, elementType, Index,
1515 StructuredList, StructuredIndex);
1516 }
1517 }
1518
CheckScalarType(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1519 void InitListChecker::CheckScalarType(const InitializedEntity &Entity,
1520 InitListExpr *IList, QualType DeclType,
1521 unsigned &Index,
1522 InitListExpr *StructuredList,
1523 unsigned &StructuredIndex) {
1524 if (Index >= IList->getNumInits()) {
1525 if (!VerifyOnly) {
1526 if (DeclType->isSizelessBuiltinType())
1527 SemaRef.Diag(IList->getBeginLoc(),
1528 SemaRef.getLangOpts().CPlusPlus11
1529 ? diag::warn_cxx98_compat_empty_sizeless_initializer
1530 : diag::err_empty_sizeless_initializer)
1531 << DeclType << IList->getSourceRange();
1532 else
1533 SemaRef.Diag(IList->getBeginLoc(),
1534 SemaRef.getLangOpts().CPlusPlus11
1535 ? diag::warn_cxx98_compat_empty_scalar_initializer
1536 : diag::err_empty_scalar_initializer)
1537 << IList->getSourceRange();
1538 }
1539 hadError = !SemaRef.getLangOpts().CPlusPlus11;
1540 ++Index;
1541 ++StructuredIndex;
1542 return;
1543 }
1544
1545 Expr *expr = IList->getInit(Index);
1546 if (InitListExpr *SubIList = dyn_cast<InitListExpr>(expr)) {
1547 // FIXME: This is invalid, and accepting it causes overload resolution
1548 // to pick the wrong overload in some corner cases.
1549 if (!VerifyOnly)
1550 SemaRef.Diag(SubIList->getBeginLoc(), diag::ext_many_braces_around_init)
1551 << DeclType->isSizelessBuiltinType() << SubIList->getSourceRange();
1552
1553 CheckScalarType(Entity, SubIList, DeclType, Index, StructuredList,
1554 StructuredIndex);
1555 return;
1556 } else if (isa<DesignatedInitExpr>(expr)) {
1557 if (!VerifyOnly)
1558 SemaRef.Diag(expr->getBeginLoc(),
1559 diag::err_designator_for_scalar_or_sizeless_init)
1560 << DeclType->isSizelessBuiltinType() << DeclType
1561 << expr->getSourceRange();
1562 hadError = true;
1563 ++Index;
1564 ++StructuredIndex;
1565 return;
1566 }
1567
1568 ExprResult Result;
1569 if (VerifyOnly) {
1570 if (SemaRef.CanPerformCopyInitialization(Entity, expr))
1571 Result = getDummyInit();
1572 else
1573 Result = ExprError();
1574 } else {
1575 Result =
1576 SemaRef.PerformCopyInitialization(Entity, expr->getBeginLoc(), expr,
1577 /*TopLevelOfInitList=*/true);
1578 }
1579
1580 Expr *ResultExpr = nullptr;
1581
1582 if (Result.isInvalid())
1583 hadError = true; // types weren't compatible.
1584 else {
1585 ResultExpr = Result.getAs<Expr>();
1586
1587 if (ResultExpr != expr && !VerifyOnly) {
1588 // The type was promoted, update initializer list.
1589 // FIXME: Why are we updating the syntactic init list?
1590 IList->setInit(Index, ResultExpr);
1591 }
1592 }
1593 UpdateStructuredListElement(StructuredList, StructuredIndex, ResultExpr);
1594 ++Index;
1595 }
1596
CheckReferenceType(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1597 void InitListChecker::CheckReferenceType(const InitializedEntity &Entity,
1598 InitListExpr *IList, QualType DeclType,
1599 unsigned &Index,
1600 InitListExpr *StructuredList,
1601 unsigned &StructuredIndex) {
1602 if (Index >= IList->getNumInits()) {
1603 // FIXME: It would be wonderful if we could point at the actual member. In
1604 // general, it would be useful to pass location information down the stack,
1605 // so that we know the location (or decl) of the "current object" being
1606 // initialized.
1607 if (!VerifyOnly)
1608 SemaRef.Diag(IList->getBeginLoc(),
1609 diag::err_init_reference_member_uninitialized)
1610 << DeclType << IList->getSourceRange();
1611 hadError = true;
1612 ++Index;
1613 ++StructuredIndex;
1614 return;
1615 }
1616
1617 Expr *expr = IList->getInit(Index);
1618 if (isa<InitListExpr>(expr) && !SemaRef.getLangOpts().CPlusPlus11) {
1619 if (!VerifyOnly)
1620 SemaRef.Diag(IList->getBeginLoc(), diag::err_init_non_aggr_init_list)
1621 << DeclType << IList->getSourceRange();
1622 hadError = true;
1623 ++Index;
1624 ++StructuredIndex;
1625 return;
1626 }
1627
1628 ExprResult Result;
1629 if (VerifyOnly) {
1630 if (SemaRef.CanPerformCopyInitialization(Entity,expr))
1631 Result = getDummyInit();
1632 else
1633 Result = ExprError();
1634 } else {
1635 Result =
1636 SemaRef.PerformCopyInitialization(Entity, expr->getBeginLoc(), expr,
1637 /*TopLevelOfInitList=*/true);
1638 }
1639
1640 if (Result.isInvalid())
1641 hadError = true;
1642
1643 expr = Result.getAs<Expr>();
1644 // FIXME: Why are we updating the syntactic init list?
1645 if (!VerifyOnly && expr)
1646 IList->setInit(Index, expr);
1647
1648 UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
1649 ++Index;
1650 }
1651
CheckVectorType(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1652 void InitListChecker::CheckVectorType(const InitializedEntity &Entity,
1653 InitListExpr *IList, QualType DeclType,
1654 unsigned &Index,
1655 InitListExpr *StructuredList,
1656 unsigned &StructuredIndex) {
1657 const VectorType *VT = DeclType->castAs<VectorType>();
1658 unsigned maxElements = VT->getNumElements();
1659 unsigned numEltsInit = 0;
1660 QualType elementType = VT->getElementType();
1661
1662 if (Index >= IList->getNumInits()) {
1663 // Make sure the element type can be value-initialized.
1664 CheckEmptyInitializable(
1665 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity),
1666 IList->getEndLoc());
1667 return;
1668 }
1669
1670 if (!SemaRef.getLangOpts().OpenCL) {
1671 // If the initializing element is a vector, try to copy-initialize
1672 // instead of breaking it apart (which is doomed to failure anyway).
1673 Expr *Init = IList->getInit(Index);
1674 if (!isa<InitListExpr>(Init) && Init->getType()->isVectorType()) {
1675 ExprResult Result;
1676 if (VerifyOnly) {
1677 if (SemaRef.CanPerformCopyInitialization(Entity, Init))
1678 Result = getDummyInit();
1679 else
1680 Result = ExprError();
1681 } else {
1682 Result =
1683 SemaRef.PerformCopyInitialization(Entity, Init->getBeginLoc(), Init,
1684 /*TopLevelOfInitList=*/true);
1685 }
1686
1687 Expr *ResultExpr = nullptr;
1688 if (Result.isInvalid())
1689 hadError = true; // types weren't compatible.
1690 else {
1691 ResultExpr = Result.getAs<Expr>();
1692
1693 if (ResultExpr != Init && !VerifyOnly) {
1694 // The type was promoted, update initializer list.
1695 // FIXME: Why are we updating the syntactic init list?
1696 IList->setInit(Index, ResultExpr);
1697 }
1698 }
1699 UpdateStructuredListElement(StructuredList, StructuredIndex, ResultExpr);
1700 ++Index;
1701 return;
1702 }
1703
1704 InitializedEntity ElementEntity =
1705 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
1706
1707 for (unsigned i = 0; i < maxElements; ++i, ++numEltsInit) {
1708 // Don't attempt to go past the end of the init list
1709 if (Index >= IList->getNumInits()) {
1710 CheckEmptyInitializable(ElementEntity, IList->getEndLoc());
1711 break;
1712 }
1713
1714 ElementEntity.setElementIndex(Index);
1715 CheckSubElementType(ElementEntity, IList, elementType, Index,
1716 StructuredList, StructuredIndex);
1717 }
1718
1719 if (VerifyOnly)
1720 return;
1721
1722 bool isBigEndian = SemaRef.Context.getTargetInfo().isBigEndian();
1723 const VectorType *T = Entity.getType()->castAs<VectorType>();
1724 if (isBigEndian && (T->getVectorKind() == VectorType::NeonVector ||
1725 T->getVectorKind() == VectorType::NeonPolyVector)) {
1726 // The ability to use vector initializer lists is a GNU vector extension
1727 // and is unrelated to the NEON intrinsics in arm_neon.h. On little
1728 // endian machines it works fine, however on big endian machines it
1729 // exhibits surprising behaviour:
1730 //
1731 // uint32x2_t x = {42, 64};
1732 // return vget_lane_u32(x, 0); // Will return 64.
1733 //
1734 // Because of this, explicitly call out that it is non-portable.
1735 //
1736 SemaRef.Diag(IList->getBeginLoc(),
1737 diag::warn_neon_vector_initializer_non_portable);
1738
1739 const char *typeCode;
1740 unsigned typeSize = SemaRef.Context.getTypeSize(elementType);
1741
1742 if (elementType->isFloatingType())
1743 typeCode = "f";
1744 else if (elementType->isSignedIntegerType())
1745 typeCode = "s";
1746 else if (elementType->isUnsignedIntegerType())
1747 typeCode = "u";
1748 else
1749 llvm_unreachable("Invalid element type!");
1750
1751 SemaRef.Diag(IList->getBeginLoc(),
1752 SemaRef.Context.getTypeSize(VT) > 64
1753 ? diag::note_neon_vector_initializer_non_portable_q
1754 : diag::note_neon_vector_initializer_non_portable)
1755 << typeCode << typeSize;
1756 }
1757
1758 return;
1759 }
1760
1761 InitializedEntity ElementEntity =
1762 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
1763
1764 // OpenCL initializers allows vectors to be constructed from vectors.
1765 for (unsigned i = 0; i < maxElements; ++i) {
1766 // Don't attempt to go past the end of the init list
1767 if (Index >= IList->getNumInits())
1768 break;
1769
1770 ElementEntity.setElementIndex(Index);
1771
1772 QualType IType = IList->getInit(Index)->getType();
1773 if (!IType->isVectorType()) {
1774 CheckSubElementType(ElementEntity, IList, elementType, Index,
1775 StructuredList, StructuredIndex);
1776 ++numEltsInit;
1777 } else {
1778 QualType VecType;
1779 const VectorType *IVT = IType->castAs<VectorType>();
1780 unsigned numIElts = IVT->getNumElements();
1781
1782 if (IType->isExtVectorType())
1783 VecType = SemaRef.Context.getExtVectorType(elementType, numIElts);
1784 else
1785 VecType = SemaRef.Context.getVectorType(elementType, numIElts,
1786 IVT->getVectorKind());
1787 CheckSubElementType(ElementEntity, IList, VecType, Index,
1788 StructuredList, StructuredIndex);
1789 numEltsInit += numIElts;
1790 }
1791 }
1792
1793 // OpenCL requires all elements to be initialized.
1794 if (numEltsInit != maxElements) {
1795 if (!VerifyOnly)
1796 SemaRef.Diag(IList->getBeginLoc(),
1797 diag::err_vector_incorrect_num_initializers)
1798 << (numEltsInit < maxElements) << maxElements << numEltsInit;
1799 hadError = true;
1800 }
1801 }
1802
1803 /// Check if the type of a class element has an accessible destructor, and marks
1804 /// it referenced. Returns true if we shouldn't form a reference to the
1805 /// destructor.
1806 ///
1807 /// Aggregate initialization requires a class element's destructor be
1808 /// accessible per 11.6.1 [dcl.init.aggr]:
1809 ///
1810 /// The destructor for each element of class type is potentially invoked
1811 /// (15.4 [class.dtor]) from the context where the aggregate initialization
1812 /// occurs.
checkDestructorReference(QualType ElementType,SourceLocation Loc,Sema & SemaRef)1813 static bool checkDestructorReference(QualType ElementType, SourceLocation Loc,
1814 Sema &SemaRef) {
1815 auto *CXXRD = ElementType->getAsCXXRecordDecl();
1816 if (!CXXRD)
1817 return false;
1818
1819 CXXDestructorDecl *Destructor = SemaRef.LookupDestructor(CXXRD);
1820 SemaRef.CheckDestructorAccess(Loc, Destructor,
1821 SemaRef.PDiag(diag::err_access_dtor_temp)
1822 << ElementType);
1823 SemaRef.MarkFunctionReferenced(Loc, Destructor);
1824 return SemaRef.DiagnoseUseOfDecl(Destructor, Loc);
1825 }
1826
CheckArrayType(const InitializedEntity & Entity,InitListExpr * IList,QualType & DeclType,llvm::APSInt elementIndex,bool SubobjectIsDesignatorContext,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex)1827 void InitListChecker::CheckArrayType(const InitializedEntity &Entity,
1828 InitListExpr *IList, QualType &DeclType,
1829 llvm::APSInt elementIndex,
1830 bool SubobjectIsDesignatorContext,
1831 unsigned &Index,
1832 InitListExpr *StructuredList,
1833 unsigned &StructuredIndex) {
1834 const ArrayType *arrayType = SemaRef.Context.getAsArrayType(DeclType);
1835
1836 if (!VerifyOnly) {
1837 if (checkDestructorReference(arrayType->getElementType(),
1838 IList->getEndLoc(), SemaRef)) {
1839 hadError = true;
1840 return;
1841 }
1842 }
1843
1844 // Check for the special-case of initializing an array with a string.
1845 if (Index < IList->getNumInits()) {
1846 if (IsStringInit(IList->getInit(Index), arrayType, SemaRef.Context) ==
1847 SIF_None) {
1848 // We place the string literal directly into the resulting
1849 // initializer list. This is the only place where the structure
1850 // of the structured initializer list doesn't match exactly,
1851 // because doing so would involve allocating one character
1852 // constant for each string.
1853 // FIXME: Should we do these checks in verify-only mode too?
1854 if (!VerifyOnly)
1855 CheckStringInit(IList->getInit(Index), DeclType, arrayType, SemaRef);
1856 if (StructuredList) {
1857 UpdateStructuredListElement(StructuredList, StructuredIndex,
1858 IList->getInit(Index));
1859 StructuredList->resizeInits(SemaRef.Context, StructuredIndex);
1860 }
1861 ++Index;
1862 return;
1863 }
1864 }
1865 if (const VariableArrayType *VAT = dyn_cast<VariableArrayType>(arrayType)) {
1866 // Check for VLAs; in standard C it would be possible to check this
1867 // earlier, but I don't know where clang accepts VLAs (gcc accepts
1868 // them in all sorts of strange places).
1869 if (!VerifyOnly)
1870 SemaRef.Diag(VAT->getSizeExpr()->getBeginLoc(),
1871 diag::err_variable_object_no_init)
1872 << VAT->getSizeExpr()->getSourceRange();
1873 hadError = true;
1874 ++Index;
1875 ++StructuredIndex;
1876 return;
1877 }
1878
1879 // We might know the maximum number of elements in advance.
1880 llvm::APSInt maxElements(elementIndex.getBitWidth(),
1881 elementIndex.isUnsigned());
1882 bool maxElementsKnown = false;
1883 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(arrayType)) {
1884 maxElements = CAT->getSize();
1885 elementIndex = elementIndex.extOrTrunc(maxElements.getBitWidth());
1886 elementIndex.setIsUnsigned(maxElements.isUnsigned());
1887 maxElementsKnown = true;
1888 }
1889
1890 QualType elementType = arrayType->getElementType();
1891 while (Index < IList->getNumInits()) {
1892 Expr *Init = IList->getInit(Index);
1893 if (DesignatedInitExpr *DIE = dyn_cast<DesignatedInitExpr>(Init)) {
1894 // If we're not the subobject that matches up with the '{' for
1895 // the designator, we shouldn't be handling the
1896 // designator. Return immediately.
1897 if (!SubobjectIsDesignatorContext)
1898 return;
1899
1900 // Handle this designated initializer. elementIndex will be
1901 // updated to be the next array element we'll initialize.
1902 if (CheckDesignatedInitializer(Entity, IList, DIE, 0,
1903 DeclType, nullptr, &elementIndex, Index,
1904 StructuredList, StructuredIndex, true,
1905 false)) {
1906 hadError = true;
1907 continue;
1908 }
1909
1910 if (elementIndex.getBitWidth() > maxElements.getBitWidth())
1911 maxElements = maxElements.extend(elementIndex.getBitWidth());
1912 else if (elementIndex.getBitWidth() < maxElements.getBitWidth())
1913 elementIndex = elementIndex.extend(maxElements.getBitWidth());
1914 elementIndex.setIsUnsigned(maxElements.isUnsigned());
1915
1916 // If the array is of incomplete type, keep track of the number of
1917 // elements in the initializer.
1918 if (!maxElementsKnown && elementIndex > maxElements)
1919 maxElements = elementIndex;
1920
1921 continue;
1922 }
1923
1924 // If we know the maximum number of elements, and we've already
1925 // hit it, stop consuming elements in the initializer list.
1926 if (maxElementsKnown && elementIndex == maxElements)
1927 break;
1928
1929 InitializedEntity ElementEntity =
1930 InitializedEntity::InitializeElement(SemaRef.Context, StructuredIndex,
1931 Entity);
1932 // Check this element.
1933 CheckSubElementType(ElementEntity, IList, elementType, Index,
1934 StructuredList, StructuredIndex);
1935 ++elementIndex;
1936
1937 // If the array is of incomplete type, keep track of the number of
1938 // elements in the initializer.
1939 if (!maxElementsKnown && elementIndex > maxElements)
1940 maxElements = elementIndex;
1941 }
1942 if (!hadError && DeclType->isIncompleteArrayType() && !VerifyOnly) {
1943 // If this is an incomplete array type, the actual type needs to
1944 // be calculated here.
1945 llvm::APSInt Zero(maxElements.getBitWidth(), maxElements.isUnsigned());
1946 if (maxElements == Zero && !Entity.isVariableLengthArrayNew()) {
1947 // Sizing an array implicitly to zero is not allowed by ISO C,
1948 // but is supported by GNU.
1949 SemaRef.Diag(IList->getBeginLoc(), diag::ext_typecheck_zero_array_size);
1950 }
1951
1952 DeclType = SemaRef.Context.getConstantArrayType(
1953 elementType, maxElements, nullptr, ArrayType::Normal, 0);
1954 }
1955 if (!hadError) {
1956 // If there are any members of the array that get value-initialized, check
1957 // that is possible. That happens if we know the bound and don't have
1958 // enough elements, or if we're performing an array new with an unknown
1959 // bound.
1960 if ((maxElementsKnown && elementIndex < maxElements) ||
1961 Entity.isVariableLengthArrayNew())
1962 CheckEmptyInitializable(
1963 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity),
1964 IList->getEndLoc());
1965 }
1966 }
1967
CheckFlexibleArrayInit(const InitializedEntity & Entity,Expr * InitExpr,FieldDecl * Field,bool TopLevelObject)1968 bool InitListChecker::CheckFlexibleArrayInit(const InitializedEntity &Entity,
1969 Expr *InitExpr,
1970 FieldDecl *Field,
1971 bool TopLevelObject) {
1972 // Handle GNU flexible array initializers.
1973 unsigned FlexArrayDiag;
1974 if (isa<InitListExpr>(InitExpr) &&
1975 cast<InitListExpr>(InitExpr)->getNumInits() == 0) {
1976 // Empty flexible array init always allowed as an extension
1977 FlexArrayDiag = diag::ext_flexible_array_init;
1978 } else if (SemaRef.getLangOpts().CPlusPlus) {
1979 // Disallow flexible array init in C++; it is not required for gcc
1980 // compatibility, and it needs work to IRGen correctly in general.
1981 FlexArrayDiag = diag::err_flexible_array_init;
1982 } else if (!TopLevelObject) {
1983 // Disallow flexible array init on non-top-level object
1984 FlexArrayDiag = diag::err_flexible_array_init;
1985 } else if (Entity.getKind() != InitializedEntity::EK_Variable) {
1986 // Disallow flexible array init on anything which is not a variable.
1987 FlexArrayDiag = diag::err_flexible_array_init;
1988 } else if (cast<VarDecl>(Entity.getDecl())->hasLocalStorage()) {
1989 // Disallow flexible array init on local variables.
1990 FlexArrayDiag = diag::err_flexible_array_init;
1991 } else {
1992 // Allow other cases.
1993 FlexArrayDiag = diag::ext_flexible_array_init;
1994 }
1995
1996 if (!VerifyOnly) {
1997 SemaRef.Diag(InitExpr->getBeginLoc(), FlexArrayDiag)
1998 << InitExpr->getBeginLoc();
1999 SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
2000 << Field;
2001 }
2002
2003 return FlexArrayDiag != diag::ext_flexible_array_init;
2004 }
2005
CheckStructUnionTypes(const InitializedEntity & Entity,InitListExpr * IList,QualType DeclType,CXXRecordDecl::base_class_range Bases,RecordDecl::field_iterator Field,bool SubobjectIsDesignatorContext,unsigned & Index,InitListExpr * StructuredList,unsigned & StructuredIndex,bool TopLevelObject)2006 void InitListChecker::CheckStructUnionTypes(
2007 const InitializedEntity &Entity, InitListExpr *IList, QualType DeclType,
2008 CXXRecordDecl::base_class_range Bases, RecordDecl::field_iterator Field,
2009 bool SubobjectIsDesignatorContext, unsigned &Index,
2010 InitListExpr *StructuredList, unsigned &StructuredIndex,
2011 bool TopLevelObject) {
2012 RecordDecl *structDecl = DeclType->castAs<RecordType>()->getDecl();
2013
2014 // If the record is invalid, some of it's members are invalid. To avoid
2015 // confusion, we forgo checking the intializer for the entire record.
2016 if (structDecl->isInvalidDecl()) {
2017 // Assume it was supposed to consume a single initializer.
2018 ++Index;
2019 hadError = true;
2020 return;
2021 }
2022
2023 if (DeclType->isUnionType() && IList->getNumInits() == 0) {
2024 RecordDecl *RD = DeclType->castAs<RecordType>()->getDecl();
2025
2026 if (!VerifyOnly)
2027 for (FieldDecl *FD : RD->fields()) {
2028 QualType ET = SemaRef.Context.getBaseElementType(FD->getType());
2029 if (checkDestructorReference(ET, IList->getEndLoc(), SemaRef)) {
2030 hadError = true;
2031 return;
2032 }
2033 }
2034
2035 // If there's a default initializer, use it.
2036 if (isa<CXXRecordDecl>(RD) &&
2037 cast<CXXRecordDecl>(RD)->hasInClassInitializer()) {
2038 if (!StructuredList)
2039 return;
2040 for (RecordDecl::field_iterator FieldEnd = RD->field_end();
2041 Field != FieldEnd; ++Field) {
2042 if (Field->hasInClassInitializer()) {
2043 StructuredList->setInitializedFieldInUnion(*Field);
2044 // FIXME: Actually build a CXXDefaultInitExpr?
2045 return;
2046 }
2047 }
2048 }
2049
2050 // Value-initialize the first member of the union that isn't an unnamed
2051 // bitfield.
2052 for (RecordDecl::field_iterator FieldEnd = RD->field_end();
2053 Field != FieldEnd; ++Field) {
2054 if (!Field->isUnnamedBitfield()) {
2055 CheckEmptyInitializable(
2056 InitializedEntity::InitializeMember(*Field, &Entity),
2057 IList->getEndLoc());
2058 if (StructuredList)
2059 StructuredList->setInitializedFieldInUnion(*Field);
2060 break;
2061 }
2062 }
2063 return;
2064 }
2065
2066 bool InitializedSomething = false;
2067
2068 // If we have any base classes, they are initialized prior to the fields.
2069 for (auto &Base : Bases) {
2070 Expr *Init = Index < IList->getNumInits() ? IList->getInit(Index) : nullptr;
2071
2072 // Designated inits always initialize fields, so if we see one, all
2073 // remaining base classes have no explicit initializer.
2074 if (Init && isa<DesignatedInitExpr>(Init))
2075 Init = nullptr;
2076
2077 SourceLocation InitLoc = Init ? Init->getBeginLoc() : IList->getEndLoc();
2078 InitializedEntity BaseEntity = InitializedEntity::InitializeBase(
2079 SemaRef.Context, &Base, false, &Entity);
2080 if (Init) {
2081 CheckSubElementType(BaseEntity, IList, Base.getType(), Index,
2082 StructuredList, StructuredIndex);
2083 InitializedSomething = true;
2084 } else {
2085 CheckEmptyInitializable(BaseEntity, InitLoc);
2086 }
2087
2088 if (!VerifyOnly)
2089 if (checkDestructorReference(Base.getType(), InitLoc, SemaRef)) {
2090 hadError = true;
2091 return;
2092 }
2093 }
2094
2095 // If structDecl is a forward declaration, this loop won't do
2096 // anything except look at designated initializers; That's okay,
2097 // because an error should get printed out elsewhere. It might be
2098 // worthwhile to skip over the rest of the initializer, though.
2099 RecordDecl *RD = DeclType->castAs<RecordType>()->getDecl();
2100 RecordDecl::field_iterator FieldEnd = RD->field_end();
2101 bool CheckForMissingFields =
2102 !IList->isIdiomaticZeroInitializer(SemaRef.getLangOpts());
2103 bool HasDesignatedInit = false;
2104
2105 while (Index < IList->getNumInits()) {
2106 Expr *Init = IList->getInit(Index);
2107 SourceLocation InitLoc = Init->getBeginLoc();
2108
2109 if (DesignatedInitExpr *DIE = dyn_cast<DesignatedInitExpr>(Init)) {
2110 // If we're not the subobject that matches up with the '{' for
2111 // the designator, we shouldn't be handling the
2112 // designator. Return immediately.
2113 if (!SubobjectIsDesignatorContext)
2114 return;
2115
2116 HasDesignatedInit = true;
2117
2118 // Handle this designated initializer. Field will be updated to
2119 // the next field that we'll be initializing.
2120 if (CheckDesignatedInitializer(Entity, IList, DIE, 0,
2121 DeclType, &Field, nullptr, Index,
2122 StructuredList, StructuredIndex,
2123 true, TopLevelObject))
2124 hadError = true;
2125 else if (!VerifyOnly) {
2126 // Find the field named by the designated initializer.
2127 RecordDecl::field_iterator F = RD->field_begin();
2128 while (std::next(F) != Field)
2129 ++F;
2130 QualType ET = SemaRef.Context.getBaseElementType(F->getType());
2131 if (checkDestructorReference(ET, InitLoc, SemaRef)) {
2132 hadError = true;
2133 return;
2134 }
2135 }
2136
2137 InitializedSomething = true;
2138
2139 // Disable check for missing fields when designators are used.
2140 // This matches gcc behaviour.
2141 CheckForMissingFields = false;
2142 continue;
2143 }
2144
2145 if (Field == FieldEnd) {
2146 // We've run out of fields. We're done.
2147 break;
2148 }
2149
2150 // We've already initialized a member of a union. We're done.
2151 if (InitializedSomething && DeclType->isUnionType())
2152 break;
2153
2154 // If we've hit the flexible array member at the end, we're done.
2155 if (Field->getType()->isIncompleteArrayType())
2156 break;
2157
2158 if (Field->isUnnamedBitfield()) {
2159 // Don't initialize unnamed bitfields, e.g. "int : 20;"
2160 ++Field;
2161 continue;
2162 }
2163
2164 // Make sure we can use this declaration.
2165 bool InvalidUse;
2166 if (VerifyOnly)
2167 InvalidUse = !SemaRef.CanUseDecl(*Field, TreatUnavailableAsInvalid);
2168 else
2169 InvalidUse = SemaRef.DiagnoseUseOfDecl(
2170 *Field, IList->getInit(Index)->getBeginLoc());
2171 if (InvalidUse) {
2172 ++Index;
2173 ++Field;
2174 hadError = true;
2175 continue;
2176 }
2177
2178 if (!VerifyOnly) {
2179 QualType ET = SemaRef.Context.getBaseElementType(Field->getType());
2180 if (checkDestructorReference(ET, InitLoc, SemaRef)) {
2181 hadError = true;
2182 return;
2183 }
2184 }
2185
2186 InitializedEntity MemberEntity =
2187 InitializedEntity::InitializeMember(*Field, &Entity);
2188 CheckSubElementType(MemberEntity, IList, Field->getType(), Index,
2189 StructuredList, StructuredIndex);
2190 InitializedSomething = true;
2191
2192 if (DeclType->isUnionType() && StructuredList) {
2193 // Initialize the first field within the union.
2194 StructuredList->setInitializedFieldInUnion(*Field);
2195 }
2196
2197 ++Field;
2198 }
2199
2200 // Emit warnings for missing struct field initializers.
2201 if (!VerifyOnly && InitializedSomething && CheckForMissingFields &&
2202 Field != FieldEnd && !Field->getType()->isIncompleteArrayType() &&
2203 !DeclType->isUnionType()) {
2204 // It is possible we have one or more unnamed bitfields remaining.
2205 // Find first (if any) named field and emit warning.
2206 for (RecordDecl::field_iterator it = Field, end = RD->field_end();
2207 it != end; ++it) {
2208 if (!it->isUnnamedBitfield() && !it->hasInClassInitializer()) {
2209 SemaRef.Diag(IList->getSourceRange().getEnd(),
2210 diag::warn_missing_field_initializers) << *it;
2211 break;
2212 }
2213 }
2214 }
2215
2216 // Check that any remaining fields can be value-initialized if we're not
2217 // building a structured list. (If we are, we'll check this later.)
2218 if (!StructuredList && Field != FieldEnd && !DeclType->isUnionType() &&
2219 !Field->getType()->isIncompleteArrayType()) {
2220 for (; Field != FieldEnd && !hadError; ++Field) {
2221 if (!Field->isUnnamedBitfield() && !Field->hasInClassInitializer())
2222 CheckEmptyInitializable(
2223 InitializedEntity::InitializeMember(*Field, &Entity),
2224 IList->getEndLoc());
2225 }
2226 }
2227
2228 // Check that the types of the remaining fields have accessible destructors.
2229 if (!VerifyOnly) {
2230 // If the initializer expression has a designated initializer, check the
2231 // elements for which a designated initializer is not provided too.
2232 RecordDecl::field_iterator I = HasDesignatedInit ? RD->field_begin()
2233 : Field;
2234 for (RecordDecl::field_iterator E = RD->field_end(); I != E; ++I) {
2235 QualType ET = SemaRef.Context.getBaseElementType(I->getType());
2236 if (checkDestructorReference(ET, IList->getEndLoc(), SemaRef)) {
2237 hadError = true;
2238 return;
2239 }
2240 }
2241 }
2242
2243 if (Field == FieldEnd || !Field->getType()->isIncompleteArrayType() ||
2244 Index >= IList->getNumInits())
2245 return;
2246
2247 if (CheckFlexibleArrayInit(Entity, IList->getInit(Index), *Field,
2248 TopLevelObject)) {
2249 hadError = true;
2250 ++Index;
2251 return;
2252 }
2253
2254 InitializedEntity MemberEntity =
2255 InitializedEntity::InitializeMember(*Field, &Entity);
2256
2257 if (isa<InitListExpr>(IList->getInit(Index)))
2258 CheckSubElementType(MemberEntity, IList, Field->getType(), Index,
2259 StructuredList, StructuredIndex);
2260 else
2261 CheckImplicitInitList(MemberEntity, IList, Field->getType(), Index,
2262 StructuredList, StructuredIndex);
2263 }
2264
2265 /// Expand a field designator that refers to a member of an
2266 /// anonymous struct or union into a series of field designators that
2267 /// refers to the field within the appropriate subobject.
2268 ///
ExpandAnonymousFieldDesignator(Sema & SemaRef,DesignatedInitExpr * DIE,unsigned DesigIdx,IndirectFieldDecl * IndirectField)2269 static void ExpandAnonymousFieldDesignator(Sema &SemaRef,
2270 DesignatedInitExpr *DIE,
2271 unsigned DesigIdx,
2272 IndirectFieldDecl *IndirectField) {
2273 typedef DesignatedInitExpr::Designator Designator;
2274
2275 // Build the replacement designators.
2276 SmallVector<Designator, 4> Replacements;
2277 for (IndirectFieldDecl::chain_iterator PI = IndirectField->chain_begin(),
2278 PE = IndirectField->chain_end(); PI != PE; ++PI) {
2279 if (PI + 1 == PE)
2280 Replacements.push_back(Designator((IdentifierInfo *)nullptr,
2281 DIE->getDesignator(DesigIdx)->getDotLoc(),
2282 DIE->getDesignator(DesigIdx)->getFieldLoc()));
2283 else
2284 Replacements.push_back(Designator((IdentifierInfo *)nullptr,
2285 SourceLocation(), SourceLocation()));
2286 assert(isa<FieldDecl>(*PI));
2287 Replacements.back().setField(cast<FieldDecl>(*PI));
2288 }
2289
2290 // Expand the current designator into the set of replacement
2291 // designators, so we have a full subobject path down to where the
2292 // member of the anonymous struct/union is actually stored.
2293 DIE->ExpandDesignator(SemaRef.Context, DesigIdx, &Replacements[0],
2294 &Replacements[0] + Replacements.size());
2295 }
2296
CloneDesignatedInitExpr(Sema & SemaRef,DesignatedInitExpr * DIE)2297 static DesignatedInitExpr *CloneDesignatedInitExpr(Sema &SemaRef,
2298 DesignatedInitExpr *DIE) {
2299 unsigned NumIndexExprs = DIE->getNumSubExprs() - 1;
2300 SmallVector<Expr*, 4> IndexExprs(NumIndexExprs);
2301 for (unsigned I = 0; I < NumIndexExprs; ++I)
2302 IndexExprs[I] = DIE->getSubExpr(I + 1);
2303 return DesignatedInitExpr::Create(SemaRef.Context, DIE->designators(),
2304 IndexExprs,
2305 DIE->getEqualOrColonLoc(),
2306 DIE->usesGNUSyntax(), DIE->getInit());
2307 }
2308
2309 namespace {
2310
2311 // Callback to only accept typo corrections that are for field members of
2312 // the given struct or union.
2313 class FieldInitializerValidatorCCC final : public CorrectionCandidateCallback {
2314 public:
FieldInitializerValidatorCCC(RecordDecl * RD)2315 explicit FieldInitializerValidatorCCC(RecordDecl *RD)
2316 : Record(RD) {}
2317
ValidateCandidate(const TypoCorrection & candidate)2318 bool ValidateCandidate(const TypoCorrection &candidate) override {
2319 FieldDecl *FD = candidate.getCorrectionDeclAs<FieldDecl>();
2320 return FD && FD->getDeclContext()->getRedeclContext()->Equals(Record);
2321 }
2322
clone()2323 std::unique_ptr<CorrectionCandidateCallback> clone() override {
2324 return std::make_unique<FieldInitializerValidatorCCC>(*this);
2325 }
2326
2327 private:
2328 RecordDecl *Record;
2329 };
2330
2331 } // end anonymous namespace
2332
2333 /// Check the well-formedness of a C99 designated initializer.
2334 ///
2335 /// Determines whether the designated initializer @p DIE, which
2336 /// resides at the given @p Index within the initializer list @p
2337 /// IList, is well-formed for a current object of type @p DeclType
2338 /// (C99 6.7.8). The actual subobject that this designator refers to
2339 /// within the current subobject is returned in either
2340 /// @p NextField or @p NextElementIndex (whichever is appropriate).
2341 ///
2342 /// @param IList The initializer list in which this designated
2343 /// initializer occurs.
2344 ///
2345 /// @param DIE The designated initializer expression.
2346 ///
2347 /// @param DesigIdx The index of the current designator.
2348 ///
2349 /// @param CurrentObjectType The type of the "current object" (C99 6.7.8p17),
2350 /// into which the designation in @p DIE should refer.
2351 ///
2352 /// @param NextField If non-NULL and the first designator in @p DIE is
2353 /// a field, this will be set to the field declaration corresponding
2354 /// to the field named by the designator. On input, this is expected to be
2355 /// the next field that would be initialized in the absence of designation,
2356 /// if the complete object being initialized is a struct.
2357 ///
2358 /// @param NextElementIndex If non-NULL and the first designator in @p
2359 /// DIE is an array designator or GNU array-range designator, this
2360 /// will be set to the last index initialized by this designator.
2361 ///
2362 /// @param Index Index into @p IList where the designated initializer
2363 /// @p DIE occurs.
2364 ///
2365 /// @param StructuredList The initializer list expression that
2366 /// describes all of the subobject initializers in the order they'll
2367 /// actually be initialized.
2368 ///
2369 /// @returns true if there was an error, false otherwise.
2370 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)2371 InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity,
2372 InitListExpr *IList,
2373 DesignatedInitExpr *DIE,
2374 unsigned DesigIdx,
2375 QualType &CurrentObjectType,
2376 RecordDecl::field_iterator *NextField,
2377 llvm::APSInt *NextElementIndex,
2378 unsigned &Index,
2379 InitListExpr *StructuredList,
2380 unsigned &StructuredIndex,
2381 bool FinishSubobjectInit,
2382 bool TopLevelObject) {
2383 if (DesigIdx == DIE->size()) {
2384 // C++20 designated initialization can result in direct-list-initialization
2385 // of the designated subobject. This is the only way that we can end up
2386 // performing direct initialization as part of aggregate initialization, so
2387 // it needs special handling.
2388 if (DIE->isDirectInit()) {
2389 Expr *Init = DIE->getInit();
2390 assert(isa<InitListExpr>(Init) &&
2391 "designator result in direct non-list initialization?");
2392 InitializationKind Kind = InitializationKind::CreateDirectList(
2393 DIE->getBeginLoc(), Init->getBeginLoc(), Init->getEndLoc());
2394 InitializationSequence Seq(SemaRef, Entity, Kind, Init,
2395 /*TopLevelOfInitList*/ true);
2396 if (StructuredList) {
2397 ExprResult Result = VerifyOnly
2398 ? getDummyInit()
2399 : Seq.Perform(SemaRef, Entity, Kind, Init);
2400 UpdateStructuredListElement(StructuredList, StructuredIndex,
2401 Result.get());
2402 }
2403 ++Index;
2404 return !Seq;
2405 }
2406
2407 // Check the actual initialization for the designated object type.
2408 bool prevHadError = hadError;
2409
2410 // Temporarily remove the designator expression from the
2411 // initializer list that the child calls see, so that we don't try
2412 // to re-process the designator.
2413 unsigned OldIndex = Index;
2414 IList->setInit(OldIndex, DIE->getInit());
2415
2416 CheckSubElementType(Entity, IList, CurrentObjectType, Index,
2417 StructuredList, StructuredIndex);
2418
2419 // Restore the designated initializer expression in the syntactic
2420 // form of the initializer list.
2421 if (IList->getInit(OldIndex) != DIE->getInit())
2422 DIE->setInit(IList->getInit(OldIndex));
2423 IList->setInit(OldIndex, DIE);
2424
2425 return hadError && !prevHadError;
2426 }
2427
2428 DesignatedInitExpr::Designator *D = DIE->getDesignator(DesigIdx);
2429 bool IsFirstDesignator = (DesigIdx == 0);
2430 if (IsFirstDesignator ? FullyStructuredList : StructuredList) {
2431 // Determine the structural initializer list that corresponds to the
2432 // current subobject.
2433 if (IsFirstDesignator)
2434 StructuredList = FullyStructuredList;
2435 else {
2436 Expr *ExistingInit = StructuredIndex < StructuredList->getNumInits() ?
2437 StructuredList->getInit(StructuredIndex) : nullptr;
2438 if (!ExistingInit && StructuredList->hasArrayFiller())
2439 ExistingInit = StructuredList->getArrayFiller();
2440
2441 if (!ExistingInit)
2442 StructuredList = getStructuredSubobjectInit(
2443 IList, Index, CurrentObjectType, StructuredList, StructuredIndex,
2444 SourceRange(D->getBeginLoc(), DIE->getEndLoc()));
2445 else if (InitListExpr *Result = dyn_cast<InitListExpr>(ExistingInit))
2446 StructuredList = Result;
2447 else {
2448 // We are creating an initializer list that initializes the
2449 // subobjects of the current object, but there was already an
2450 // initialization that completely initialized the current
2451 // subobject, e.g., by a compound literal:
2452 //
2453 // struct X { int a, b; };
2454 // struct X xs[] = { [0] = (struct X) { 1, 2 }, [0].b = 3 };
2455 //
2456 // Here, xs[0].a == 1 and xs[0].b == 3, since the second,
2457 // designated initializer re-initializes only its current object
2458 // subobject [0].b.
2459 diagnoseInitOverride(ExistingInit,
2460 SourceRange(D->getBeginLoc(), DIE->getEndLoc()),
2461 /*FullyOverwritten=*/false);
2462
2463 if (!VerifyOnly) {
2464 if (DesignatedInitUpdateExpr *E =
2465 dyn_cast<DesignatedInitUpdateExpr>(ExistingInit))
2466 StructuredList = E->getUpdater();
2467 else {
2468 DesignatedInitUpdateExpr *DIUE = new (SemaRef.Context)
2469 DesignatedInitUpdateExpr(SemaRef.Context, D->getBeginLoc(),
2470 ExistingInit, DIE->getEndLoc());
2471 StructuredList->updateInit(SemaRef.Context, StructuredIndex, DIUE);
2472 StructuredList = DIUE->getUpdater();
2473 }
2474 } else {
2475 // We don't need to track the structured representation of a
2476 // designated init update of an already-fully-initialized object in
2477 // verify-only mode. The only reason we would need the structure is
2478 // to determine where the uninitialized "holes" are, and in this
2479 // case, we know there aren't any and we can't introduce any.
2480 StructuredList = nullptr;
2481 }
2482 }
2483 }
2484 }
2485
2486 if (D->isFieldDesignator()) {
2487 // C99 6.7.8p7:
2488 //
2489 // If a designator has the form
2490 //
2491 // . identifier
2492 //
2493 // then the current object (defined below) shall have
2494 // structure or union type and the identifier shall be the
2495 // name of a member of that type.
2496 const RecordType *RT = CurrentObjectType->getAs<RecordType>();
2497 if (!RT) {
2498 SourceLocation Loc = D->getDotLoc();
2499 if (Loc.isInvalid())
2500 Loc = D->getFieldLoc();
2501 if (!VerifyOnly)
2502 SemaRef.Diag(Loc, diag::err_field_designator_non_aggr)
2503 << SemaRef.getLangOpts().CPlusPlus << CurrentObjectType;
2504 ++Index;
2505 return true;
2506 }
2507
2508 FieldDecl *KnownField = D->getField();
2509 if (!KnownField) {
2510 IdentifierInfo *FieldName = D->getFieldName();
2511 DeclContext::lookup_result Lookup = RT->getDecl()->lookup(FieldName);
2512 for (NamedDecl *ND : Lookup) {
2513 if (auto *FD = dyn_cast<FieldDecl>(ND)) {
2514 KnownField = FD;
2515 break;
2516 }
2517 if (auto *IFD = dyn_cast<IndirectFieldDecl>(ND)) {
2518 // In verify mode, don't modify the original.
2519 if (VerifyOnly)
2520 DIE = CloneDesignatedInitExpr(SemaRef, DIE);
2521 ExpandAnonymousFieldDesignator(SemaRef, DIE, DesigIdx, IFD);
2522 D = DIE->getDesignator(DesigIdx);
2523 KnownField = cast<FieldDecl>(*IFD->chain_begin());
2524 break;
2525 }
2526 }
2527 if (!KnownField) {
2528 if (VerifyOnly) {
2529 ++Index;
2530 return true; // No typo correction when just trying this out.
2531 }
2532
2533 // Name lookup found something, but it wasn't a field.
2534 if (!Lookup.empty()) {
2535 SemaRef.Diag(D->getFieldLoc(), diag::err_field_designator_nonfield)
2536 << FieldName;
2537 SemaRef.Diag(Lookup.front()->getLocation(),
2538 diag::note_field_designator_found);
2539 ++Index;
2540 return true;
2541 }
2542
2543 // Name lookup didn't find anything.
2544 // Determine whether this was a typo for another field name.
2545 FieldInitializerValidatorCCC CCC(RT->getDecl());
2546 if (TypoCorrection Corrected = SemaRef.CorrectTypo(
2547 DeclarationNameInfo(FieldName, D->getFieldLoc()),
2548 Sema::LookupMemberName, /*Scope=*/nullptr, /*SS=*/nullptr, CCC,
2549 Sema::CTK_ErrorRecovery, RT->getDecl())) {
2550 SemaRef.diagnoseTypo(
2551 Corrected,
2552 SemaRef.PDiag(diag::err_field_designator_unknown_suggest)
2553 << FieldName << CurrentObjectType);
2554 KnownField = Corrected.getCorrectionDeclAs<FieldDecl>();
2555 hadError = true;
2556 } else {
2557 // Typo correction didn't find anything.
2558 SemaRef.Diag(D->getFieldLoc(), diag::err_field_designator_unknown)
2559 << FieldName << CurrentObjectType;
2560 ++Index;
2561 return true;
2562 }
2563 }
2564 }
2565
2566 unsigned NumBases = 0;
2567 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RT->getDecl()))
2568 NumBases = CXXRD->getNumBases();
2569
2570 unsigned FieldIndex = NumBases;
2571
2572 for (auto *FI : RT->getDecl()->fields()) {
2573 if (FI->isUnnamedBitfield())
2574 continue;
2575 if (declaresSameEntity(KnownField, FI)) {
2576 KnownField = FI;
2577 break;
2578 }
2579 ++FieldIndex;
2580 }
2581
2582 RecordDecl::field_iterator Field =
2583 RecordDecl::field_iterator(DeclContext::decl_iterator(KnownField));
2584
2585 // All of the fields of a union are located at the same place in
2586 // the initializer list.
2587 if (RT->getDecl()->isUnion()) {
2588 FieldIndex = 0;
2589 if (StructuredList) {
2590 FieldDecl *CurrentField = StructuredList->getInitializedFieldInUnion();
2591 if (CurrentField && !declaresSameEntity(CurrentField, *Field)) {
2592 assert(StructuredList->getNumInits() == 1
2593 && "A union should never have more than one initializer!");
2594
2595 Expr *ExistingInit = StructuredList->getInit(0);
2596 if (ExistingInit) {
2597 // We're about to throw away an initializer, emit warning.
2598 diagnoseInitOverride(
2599 ExistingInit, SourceRange(D->getBeginLoc(), DIE->getEndLoc()));
2600 }
2601
2602 // remove existing initializer
2603 StructuredList->resizeInits(SemaRef.Context, 0);
2604 StructuredList->setInitializedFieldInUnion(nullptr);
2605 }
2606
2607 StructuredList->setInitializedFieldInUnion(*Field);
2608 }
2609 }
2610
2611 // Make sure we can use this declaration.
2612 bool InvalidUse;
2613 if (VerifyOnly)
2614 InvalidUse = !SemaRef.CanUseDecl(*Field, TreatUnavailableAsInvalid);
2615 else
2616 InvalidUse = SemaRef.DiagnoseUseOfDecl(*Field, D->getFieldLoc());
2617 if (InvalidUse) {
2618 ++Index;
2619 return true;
2620 }
2621
2622 // C++20 [dcl.init.list]p3:
2623 // The ordered identifiers in the designators of the designated-
2624 // initializer-list shall form a subsequence of the ordered identifiers
2625 // in the direct non-static data members of T.
2626 //
2627 // Note that this is not a condition on forming the aggregate
2628 // initialization, only on actually performing initialization,
2629 // so it is not checked in VerifyOnly mode.
2630 //
2631 // FIXME: This is the only reordering diagnostic we produce, and it only
2632 // catches cases where we have a top-level field designator that jumps
2633 // backwards. This is the only such case that is reachable in an
2634 // otherwise-valid C++20 program, so is the only case that's required for
2635 // conformance, but for consistency, we should diagnose all the other
2636 // cases where a designator takes us backwards too.
2637 if (IsFirstDesignator && !VerifyOnly && SemaRef.getLangOpts().CPlusPlus &&
2638 NextField &&
2639 (*NextField == RT->getDecl()->field_end() ||
2640 (*NextField)->getFieldIndex() > Field->getFieldIndex() + 1)) {
2641 // Find the field that we just initialized.
2642 FieldDecl *PrevField = nullptr;
2643 for (auto FI = RT->getDecl()->field_begin();
2644 FI != RT->getDecl()->field_end(); ++FI) {
2645 if (FI->isUnnamedBitfield())
2646 continue;
2647 if (*NextField != RT->getDecl()->field_end() &&
2648 declaresSameEntity(*FI, **NextField))
2649 break;
2650 PrevField = *FI;
2651 }
2652
2653 if (PrevField &&
2654 PrevField->getFieldIndex() > KnownField->getFieldIndex()) {
2655 SemaRef.Diag(DIE->getBeginLoc(), diag::ext_designated_init_reordered)
2656 << KnownField << PrevField << DIE->getSourceRange();
2657
2658 unsigned OldIndex = NumBases + PrevField->getFieldIndex();
2659 if (StructuredList && OldIndex <= StructuredList->getNumInits()) {
2660 if (Expr *PrevInit = StructuredList->getInit(OldIndex)) {
2661 SemaRef.Diag(PrevInit->getBeginLoc(),
2662 diag::note_previous_field_init)
2663 << PrevField << PrevInit->getSourceRange();
2664 }
2665 }
2666 }
2667 }
2668
2669
2670 // Update the designator with the field declaration.
2671 if (!VerifyOnly)
2672 D->setField(*Field);
2673
2674 // Make sure that our non-designated initializer list has space
2675 // for a subobject corresponding to this field.
2676 if (StructuredList && FieldIndex >= StructuredList->getNumInits())
2677 StructuredList->resizeInits(SemaRef.Context, FieldIndex + 1);
2678
2679 // This designator names a flexible array member.
2680 if (Field->getType()->isIncompleteArrayType()) {
2681 bool Invalid = false;
2682 if ((DesigIdx + 1) != DIE->size()) {
2683 // We can't designate an object within the flexible array
2684 // member (because GCC doesn't allow it).
2685 if (!VerifyOnly) {
2686 DesignatedInitExpr::Designator *NextD
2687 = DIE->getDesignator(DesigIdx + 1);
2688 SemaRef.Diag(NextD->getBeginLoc(),
2689 diag::err_designator_into_flexible_array_member)
2690 << SourceRange(NextD->getBeginLoc(), DIE->getEndLoc());
2691 SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
2692 << *Field;
2693 }
2694 Invalid = true;
2695 }
2696
2697 if (!hadError && !isa<InitListExpr>(DIE->getInit()) &&
2698 !isa<StringLiteral>(DIE->getInit())) {
2699 // The initializer is not an initializer list.
2700 if (!VerifyOnly) {
2701 SemaRef.Diag(DIE->getInit()->getBeginLoc(),
2702 diag::err_flexible_array_init_needs_braces)
2703 << DIE->getInit()->getSourceRange();
2704 SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
2705 << *Field;
2706 }
2707 Invalid = true;
2708 }
2709
2710 // Check GNU flexible array initializer.
2711 if (!Invalid && CheckFlexibleArrayInit(Entity, DIE->getInit(), *Field,
2712 TopLevelObject))
2713 Invalid = true;
2714
2715 if (Invalid) {
2716 ++Index;
2717 return true;
2718 }
2719
2720 // Initialize the array.
2721 bool prevHadError = hadError;
2722 unsigned newStructuredIndex = FieldIndex;
2723 unsigned OldIndex = Index;
2724 IList->setInit(Index, DIE->getInit());
2725
2726 InitializedEntity MemberEntity =
2727 InitializedEntity::InitializeMember(*Field, &Entity);
2728 CheckSubElementType(MemberEntity, IList, Field->getType(), Index,
2729 StructuredList, newStructuredIndex);
2730
2731 IList->setInit(OldIndex, DIE);
2732 if (hadError && !prevHadError) {
2733 ++Field;
2734 ++FieldIndex;
2735 if (NextField)
2736 *NextField = Field;
2737 StructuredIndex = FieldIndex;
2738 return true;
2739 }
2740 } else {
2741 // Recurse to check later designated subobjects.
2742 QualType FieldType = Field->getType();
2743 unsigned newStructuredIndex = FieldIndex;
2744
2745 InitializedEntity MemberEntity =
2746 InitializedEntity::InitializeMember(*Field, &Entity);
2747 if (CheckDesignatedInitializer(MemberEntity, IList, DIE, DesigIdx + 1,
2748 FieldType, nullptr, nullptr, Index,
2749 StructuredList, newStructuredIndex,
2750 FinishSubobjectInit, false))
2751 return true;
2752 }
2753
2754 // Find the position of the next field to be initialized in this
2755 // subobject.
2756 ++Field;
2757 ++FieldIndex;
2758
2759 // If this the first designator, our caller will continue checking
2760 // the rest of this struct/class/union subobject.
2761 if (IsFirstDesignator) {
2762 if (NextField)
2763 *NextField = Field;
2764 StructuredIndex = FieldIndex;
2765 return false;
2766 }
2767
2768 if (!FinishSubobjectInit)
2769 return false;
2770
2771 // We've already initialized something in the union; we're done.
2772 if (RT->getDecl()->isUnion())
2773 return hadError;
2774
2775 // Check the remaining fields within this class/struct/union subobject.
2776 bool prevHadError = hadError;
2777
2778 auto NoBases =
2779 CXXRecordDecl::base_class_range(CXXRecordDecl::base_class_iterator(),
2780 CXXRecordDecl::base_class_iterator());
2781 CheckStructUnionTypes(Entity, IList, CurrentObjectType, NoBases, Field,
2782 false, Index, StructuredList, FieldIndex);
2783 return hadError && !prevHadError;
2784 }
2785
2786 // C99 6.7.8p6:
2787 //
2788 // If a designator has the form
2789 //
2790 // [ constant-expression ]
2791 //
2792 // then the current object (defined below) shall have array
2793 // type and the expression shall be an integer constant
2794 // expression. If the array is of unknown size, any
2795 // nonnegative value is valid.
2796 //
2797 // Additionally, cope with the GNU extension that permits
2798 // designators of the form
2799 //
2800 // [ constant-expression ... constant-expression ]
2801 const ArrayType *AT = SemaRef.Context.getAsArrayType(CurrentObjectType);
2802 if (!AT) {
2803 if (!VerifyOnly)
2804 SemaRef.Diag(D->getLBracketLoc(), diag::err_array_designator_non_array)
2805 << CurrentObjectType;
2806 ++Index;
2807 return true;
2808 }
2809
2810 Expr *IndexExpr = nullptr;
2811 llvm::APSInt DesignatedStartIndex, DesignatedEndIndex;
2812 if (D->isArrayDesignator()) {
2813 IndexExpr = DIE->getArrayIndex(*D);
2814 DesignatedStartIndex = IndexExpr->EvaluateKnownConstInt(SemaRef.Context);
2815 DesignatedEndIndex = DesignatedStartIndex;
2816 } else {
2817 assert(D->isArrayRangeDesignator() && "Need array-range designator");
2818
2819 DesignatedStartIndex =
2820 DIE->getArrayRangeStart(*D)->EvaluateKnownConstInt(SemaRef.Context);
2821 DesignatedEndIndex =
2822 DIE->getArrayRangeEnd(*D)->EvaluateKnownConstInt(SemaRef.Context);
2823 IndexExpr = DIE->getArrayRangeEnd(*D);
2824
2825 // Codegen can't handle evaluating array range designators that have side
2826 // effects, because we replicate the AST value for each initialized element.
2827 // As such, set the sawArrayRangeDesignator() bit if we initialize multiple
2828 // elements with something that has a side effect, so codegen can emit an
2829 // "error unsupported" error instead of miscompiling the app.
2830 if (DesignatedStartIndex.getZExtValue()!=DesignatedEndIndex.getZExtValue()&&
2831 DIE->getInit()->HasSideEffects(SemaRef.Context) && !VerifyOnly)
2832 FullyStructuredList->sawArrayRangeDesignator();
2833 }
2834
2835 if (isa<ConstantArrayType>(AT)) {
2836 llvm::APSInt MaxElements(cast<ConstantArrayType>(AT)->getSize(), false);
2837 DesignatedStartIndex
2838 = DesignatedStartIndex.extOrTrunc(MaxElements.getBitWidth());
2839 DesignatedStartIndex.setIsUnsigned(MaxElements.isUnsigned());
2840 DesignatedEndIndex
2841 = DesignatedEndIndex.extOrTrunc(MaxElements.getBitWidth());
2842 DesignatedEndIndex.setIsUnsigned(MaxElements.isUnsigned());
2843 if (DesignatedEndIndex >= MaxElements) {
2844 if (!VerifyOnly)
2845 SemaRef.Diag(IndexExpr->getBeginLoc(),
2846 diag::err_array_designator_too_large)
2847 << DesignatedEndIndex.toString(10) << MaxElements.toString(10)
2848 << IndexExpr->getSourceRange();
2849 ++Index;
2850 return true;
2851 }
2852 } else {
2853 unsigned DesignatedIndexBitWidth =
2854 ConstantArrayType::getMaxSizeBits(SemaRef.Context);
2855 DesignatedStartIndex =
2856 DesignatedStartIndex.extOrTrunc(DesignatedIndexBitWidth);
2857 DesignatedEndIndex =
2858 DesignatedEndIndex.extOrTrunc(DesignatedIndexBitWidth);
2859 DesignatedStartIndex.setIsUnsigned(true);
2860 DesignatedEndIndex.setIsUnsigned(true);
2861 }
2862
2863 bool IsStringLiteralInitUpdate =
2864 StructuredList && StructuredList->isStringLiteralInit();
2865 if (IsStringLiteralInitUpdate && VerifyOnly) {
2866 // We're just verifying an update to a string literal init. We don't need
2867 // to split the string up into individual characters to do that.
2868 StructuredList = nullptr;
2869 } else if (IsStringLiteralInitUpdate) {
2870 // We're modifying a string literal init; we have to decompose the string
2871 // so we can modify the individual characters.
2872 ASTContext &Context = SemaRef.Context;
2873 Expr *SubExpr = StructuredList->getInit(0)->IgnoreParens();
2874
2875 // Compute the character type
2876 QualType CharTy = AT->getElementType();
2877
2878 // Compute the type of the integer literals.
2879 QualType PromotedCharTy = CharTy;
2880 if (CharTy->isPromotableIntegerType())
2881 PromotedCharTy = Context.getPromotedIntegerType(CharTy);
2882 unsigned PromotedCharTyWidth = Context.getTypeSize(PromotedCharTy);
2883
2884 if (StringLiteral *SL = dyn_cast<StringLiteral>(SubExpr)) {
2885 // Get the length of the string.
2886 uint64_t StrLen = SL->getLength();
2887 if (cast<ConstantArrayType>(AT)->getSize().ult(StrLen))
2888 StrLen = cast<ConstantArrayType>(AT)->getSize().getZExtValue();
2889 StructuredList->resizeInits(Context, StrLen);
2890
2891 // Build a literal for each character in the string, and put them into
2892 // the init list.
2893 for (unsigned i = 0, e = StrLen; i != e; ++i) {
2894 llvm::APInt CodeUnit(PromotedCharTyWidth, SL->getCodeUnit(i));
2895 Expr *Init = new (Context) IntegerLiteral(
2896 Context, CodeUnit, PromotedCharTy, SubExpr->getExprLoc());
2897 if (CharTy != PromotedCharTy)
2898 Init =
2899 ImplicitCastExpr::Create(Context, CharTy, CK_IntegralCast, Init,
2900 nullptr, VK_RValue, FPOptionsOverride());
2901 StructuredList->updateInit(Context, i, Init);
2902 }
2903 } else {
2904 ObjCEncodeExpr *E = cast<ObjCEncodeExpr>(SubExpr);
2905 std::string Str;
2906 Context.getObjCEncodingForType(E->getEncodedType(), Str);
2907
2908 // Get the length of the string.
2909 uint64_t StrLen = Str.size();
2910 if (cast<ConstantArrayType>(AT)->getSize().ult(StrLen))
2911 StrLen = cast<ConstantArrayType>(AT)->getSize().getZExtValue();
2912 StructuredList->resizeInits(Context, StrLen);
2913
2914 // Build a literal for each character in the string, and put them into
2915 // the init list.
2916 for (unsigned i = 0, e = StrLen; i != e; ++i) {
2917 llvm::APInt CodeUnit(PromotedCharTyWidth, Str[i]);
2918 Expr *Init = new (Context) IntegerLiteral(
2919 Context, CodeUnit, PromotedCharTy, SubExpr->getExprLoc());
2920 if (CharTy != PromotedCharTy)
2921 Init =
2922 ImplicitCastExpr::Create(Context, CharTy, CK_IntegralCast, Init,
2923 nullptr, VK_RValue, FPOptionsOverride());
2924 StructuredList->updateInit(Context, i, Init);
2925 }
2926 }
2927 }
2928
2929 // Make sure that our non-designated initializer list has space
2930 // for a subobject corresponding to this array element.
2931 if (StructuredList &&
2932 DesignatedEndIndex.getZExtValue() >= StructuredList->getNumInits())
2933 StructuredList->resizeInits(SemaRef.Context,
2934 DesignatedEndIndex.getZExtValue() + 1);
2935
2936 // Repeatedly perform subobject initializations in the range
2937 // [DesignatedStartIndex, DesignatedEndIndex].
2938
2939 // Move to the next designator
2940 unsigned ElementIndex = DesignatedStartIndex.getZExtValue();
2941 unsigned OldIndex = Index;
2942
2943 InitializedEntity ElementEntity =
2944 InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
2945
2946 while (DesignatedStartIndex <= DesignatedEndIndex) {
2947 // Recurse to check later designated subobjects.
2948 QualType ElementType = AT->getElementType();
2949 Index = OldIndex;
2950
2951 ElementEntity.setElementIndex(ElementIndex);
2952 if (CheckDesignatedInitializer(
2953 ElementEntity, IList, DIE, DesigIdx + 1, ElementType, nullptr,
2954 nullptr, Index, StructuredList, ElementIndex,
2955 FinishSubobjectInit && (DesignatedStartIndex == DesignatedEndIndex),
2956 false))
2957 return true;
2958
2959 // Move to the next index in the array that we'll be initializing.
2960 ++DesignatedStartIndex;
2961 ElementIndex = DesignatedStartIndex.getZExtValue();
2962 }
2963
2964 // If this the first designator, our caller will continue checking
2965 // the rest of this array subobject.
2966 if (IsFirstDesignator) {
2967 if (NextElementIndex)
2968 *NextElementIndex = DesignatedStartIndex;
2969 StructuredIndex = ElementIndex;
2970 return false;
2971 }
2972
2973 if (!FinishSubobjectInit)
2974 return false;
2975
2976 // Check the remaining elements within this array subobject.
2977 bool prevHadError = hadError;
2978 CheckArrayType(Entity, IList, CurrentObjectType, DesignatedStartIndex,
2979 /*SubobjectIsDesignatorContext=*/false, Index,
2980 StructuredList, ElementIndex);
2981 return hadError && !prevHadError;
2982 }
2983
2984 // Get the structured initializer list for a subobject of type
2985 // @p CurrentObjectType.
2986 InitListExpr *
getStructuredSubobjectInit(InitListExpr * IList,unsigned Index,QualType CurrentObjectType,InitListExpr * StructuredList,unsigned StructuredIndex,SourceRange InitRange,bool IsFullyOverwritten)2987 InitListChecker::getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
2988 QualType CurrentObjectType,
2989 InitListExpr *StructuredList,
2990 unsigned StructuredIndex,
2991 SourceRange InitRange,
2992 bool IsFullyOverwritten) {
2993 if (!StructuredList)
2994 return nullptr;
2995
2996 Expr *ExistingInit = nullptr;
2997 if (StructuredIndex < StructuredList->getNumInits())
2998 ExistingInit = StructuredList->getInit(StructuredIndex);
2999
3000 if (InitListExpr *Result = dyn_cast_or_null<InitListExpr>(ExistingInit))
3001 // There might have already been initializers for subobjects of the current
3002 // object, but a subsequent initializer list will overwrite the entirety
3003 // of the current object. (See DR 253 and C99 6.7.8p21). e.g.,
3004 //
3005 // struct P { char x[6]; };
3006 // struct P l = { .x[2] = 'x', .x = { [0] = 'f' } };
3007 //
3008 // The first designated initializer is ignored, and l.x is just "f".
3009 if (!IsFullyOverwritten)
3010 return Result;
3011
3012 if (ExistingInit) {
3013 // We are creating an initializer list that initializes the
3014 // subobjects of the current object, but there was already an
3015 // initialization that completely initialized the current
3016 // subobject:
3017 //
3018 // struct X { int a, b; };
3019 // struct X xs[] = { [0] = { 1, 2 }, [0].b = 3 };
3020 //
3021 // Here, xs[0].a == 1 and xs[0].b == 3, since the second,
3022 // designated initializer overwrites the [0].b initializer
3023 // from the prior initialization.
3024 //
3025 // When the existing initializer is an expression rather than an
3026 // initializer list, we cannot decompose and update it in this way.
3027 // For example:
3028 //
3029 // struct X xs[] = { [0] = (struct X) { 1, 2 }, [0].b = 3 };
3030 //
3031 // This case is handled by CheckDesignatedInitializer.
3032 diagnoseInitOverride(ExistingInit, InitRange);
3033 }
3034
3035 unsigned ExpectedNumInits = 0;
3036 if (Index < IList->getNumInits()) {
3037 if (auto *Init = dyn_cast_or_null<InitListExpr>(IList->getInit(Index)))
3038 ExpectedNumInits = Init->getNumInits();
3039 else
3040 ExpectedNumInits = IList->getNumInits() - Index;
3041 }
3042
3043 InitListExpr *Result =
3044 createInitListExpr(CurrentObjectType, InitRange, ExpectedNumInits);
3045
3046 // Link this new initializer list into the structured initializer
3047 // lists.
3048 StructuredList->updateInit(SemaRef.Context, StructuredIndex, Result);
3049 return Result;
3050 }
3051
3052 InitListExpr *
createInitListExpr(QualType CurrentObjectType,SourceRange InitRange,unsigned ExpectedNumInits)3053 InitListChecker::createInitListExpr(QualType CurrentObjectType,
3054 SourceRange InitRange,
3055 unsigned ExpectedNumInits) {
3056 InitListExpr *Result
3057 = new (SemaRef.Context) InitListExpr(SemaRef.Context,
3058 InitRange.getBegin(), None,
3059 InitRange.getEnd());
3060
3061 QualType ResultType = CurrentObjectType;
3062 if (!ResultType->isArrayType())
3063 ResultType = ResultType.getNonLValueExprType(SemaRef.Context);
3064 Result->setType(ResultType);
3065
3066 // Pre-allocate storage for the structured initializer list.
3067 unsigned NumElements = 0;
3068
3069 if (const ArrayType *AType
3070 = SemaRef.Context.getAsArrayType(CurrentObjectType)) {
3071 if (const ConstantArrayType *CAType = dyn_cast<ConstantArrayType>(AType)) {
3072 NumElements = CAType->getSize().getZExtValue();
3073 // Simple heuristic so that we don't allocate a very large
3074 // initializer with many empty entries at the end.
3075 if (NumElements > ExpectedNumInits)
3076 NumElements = 0;
3077 }
3078 } else if (const VectorType *VType = CurrentObjectType->getAs<VectorType>()) {
3079 NumElements = VType->getNumElements();
3080 } else if (CurrentObjectType->isRecordType()) {
3081 NumElements = numStructUnionElements(CurrentObjectType);
3082 }
3083
3084 Result->reserveInits(SemaRef.Context, NumElements);
3085
3086 return Result;
3087 }
3088
3089 /// Update the initializer at index @p StructuredIndex within the
3090 /// structured initializer list to the value @p expr.
UpdateStructuredListElement(InitListExpr * StructuredList,unsigned & StructuredIndex,Expr * expr)3091 void InitListChecker::UpdateStructuredListElement(InitListExpr *StructuredList,
3092 unsigned &StructuredIndex,
3093 Expr *expr) {
3094 // No structured initializer list to update
3095 if (!StructuredList)
3096 return;
3097
3098 if (Expr *PrevInit = StructuredList->updateInit(SemaRef.Context,
3099 StructuredIndex, expr)) {
3100 // This initializer overwrites a previous initializer.
3101 // No need to diagnose when `expr` is nullptr because a more relevant
3102 // diagnostic has already been issued and this diagnostic is potentially
3103 // noise.
3104 if (expr)
3105 diagnoseInitOverride(PrevInit, expr->getSourceRange());
3106 }
3107
3108 ++StructuredIndex;
3109 }
3110
3111 /// Determine whether we can perform aggregate initialization for the purposes
3112 /// of overload resolution.
CanPerformAggregateInitializationForOverloadResolution(const InitializedEntity & Entity,InitListExpr * From)3113 bool Sema::CanPerformAggregateInitializationForOverloadResolution(
3114 const InitializedEntity &Entity, InitListExpr *From) {
3115 QualType Type = Entity.getType();
3116 InitListChecker Check(*this, Entity, From, Type, /*VerifyOnly=*/true,
3117 /*TreatUnavailableAsInvalid=*/false,
3118 /*InOverloadResolution=*/true);
3119 return !Check.HadError();
3120 }
3121
3122 /// Check that the given Index expression is a valid array designator
3123 /// value. This is essentially just a wrapper around
3124 /// VerifyIntegerConstantExpression that also checks for negative values
3125 /// and produces a reasonable diagnostic if there is a
3126 /// failure. Returns the index expression, possibly with an implicit cast
3127 /// added, on success. If everything went okay, Value will receive the
3128 /// value of the constant expression.
3129 static ExprResult
CheckArrayDesignatorExpr(Sema & S,Expr * Index,llvm::APSInt & Value)3130 CheckArrayDesignatorExpr(Sema &S, Expr *Index, llvm::APSInt &Value) {
3131 SourceLocation Loc = Index->getBeginLoc();
3132
3133 // Make sure this is an integer constant expression.
3134 ExprResult Result =
3135 S.VerifyIntegerConstantExpression(Index, &Value, Sema::AllowFold);
3136 if (Result.isInvalid())
3137 return Result;
3138
3139 if (Value.isSigned() && Value.isNegative())
3140 return S.Diag(Loc, diag::err_array_designator_negative)
3141 << Value.toString(10) << Index->getSourceRange();
3142
3143 Value.setIsUnsigned(true);
3144 return Result;
3145 }
3146
ActOnDesignatedInitializer(Designation & Desig,SourceLocation EqualOrColonLoc,bool GNUSyntax,ExprResult Init)3147 ExprResult Sema::ActOnDesignatedInitializer(Designation &Desig,
3148 SourceLocation EqualOrColonLoc,
3149 bool GNUSyntax,
3150 ExprResult Init) {
3151 typedef DesignatedInitExpr::Designator ASTDesignator;
3152
3153 bool Invalid = false;
3154 SmallVector<ASTDesignator, 32> Designators;
3155 SmallVector<Expr *, 32> InitExpressions;
3156
3157 // Build designators and check array designator expressions.
3158 for (unsigned Idx = 0; Idx < Desig.getNumDesignators(); ++Idx) {
3159 const Designator &D = Desig.getDesignator(Idx);
3160 switch (D.getKind()) {
3161 case Designator::FieldDesignator:
3162 Designators.push_back(ASTDesignator(D.getField(), D.getDotLoc(),
3163 D.getFieldLoc()));
3164 break;
3165
3166 case Designator::ArrayDesignator: {
3167 Expr *Index = static_cast<Expr *>(D.getArrayIndex());
3168 llvm::APSInt IndexValue;
3169 if (!Index->isTypeDependent() && !Index->isValueDependent())
3170 Index = CheckArrayDesignatorExpr(*this, Index, IndexValue).get();
3171 if (!Index)
3172 Invalid = true;
3173 else {
3174 Designators.push_back(ASTDesignator(InitExpressions.size(),
3175 D.getLBracketLoc(),
3176 D.getRBracketLoc()));
3177 InitExpressions.push_back(Index);
3178 }
3179 break;
3180 }
3181
3182 case Designator::ArrayRangeDesignator: {
3183 Expr *StartIndex = static_cast<Expr *>(D.getArrayRangeStart());
3184 Expr *EndIndex = static_cast<Expr *>(D.getArrayRangeEnd());
3185 llvm::APSInt StartValue;
3186 llvm::APSInt EndValue;
3187 bool StartDependent = StartIndex->isTypeDependent() ||
3188 StartIndex->isValueDependent();
3189 bool EndDependent = EndIndex->isTypeDependent() ||
3190 EndIndex->isValueDependent();
3191 if (!StartDependent)
3192 StartIndex =
3193 CheckArrayDesignatorExpr(*this, StartIndex, StartValue).get();
3194 if (!EndDependent)
3195 EndIndex = CheckArrayDesignatorExpr(*this, EndIndex, EndValue).get();
3196
3197 if (!StartIndex || !EndIndex)
3198 Invalid = true;
3199 else {
3200 // Make sure we're comparing values with the same bit width.
3201 if (StartDependent || EndDependent) {
3202 // Nothing to compute.
3203 } else if (StartValue.getBitWidth() > EndValue.getBitWidth())
3204 EndValue = EndValue.extend(StartValue.getBitWidth());
3205 else if (StartValue.getBitWidth() < EndValue.getBitWidth())
3206 StartValue = StartValue.extend(EndValue.getBitWidth());
3207
3208 if (!StartDependent && !EndDependent && EndValue < StartValue) {
3209 Diag(D.getEllipsisLoc(), diag::err_array_designator_empty_range)
3210 << StartValue.toString(10) << EndValue.toString(10)
3211 << StartIndex->getSourceRange() << EndIndex->getSourceRange();
3212 Invalid = true;
3213 } else {
3214 Designators.push_back(ASTDesignator(InitExpressions.size(),
3215 D.getLBracketLoc(),
3216 D.getEllipsisLoc(),
3217 D.getRBracketLoc()));
3218 InitExpressions.push_back(StartIndex);
3219 InitExpressions.push_back(EndIndex);
3220 }
3221 }
3222 break;
3223 }
3224 }
3225 }
3226
3227 if (Invalid || Init.isInvalid())
3228 return ExprError();
3229
3230 // Clear out the expressions within the designation.
3231 Desig.ClearExprs(*this);
3232
3233 return DesignatedInitExpr::Create(Context, Designators, InitExpressions,
3234 EqualOrColonLoc, GNUSyntax,
3235 Init.getAs<Expr>());
3236 }
3237
3238 //===----------------------------------------------------------------------===//
3239 // Initialization entity
3240 //===----------------------------------------------------------------------===//
3241
InitializedEntity(ASTContext & Context,unsigned Index,const InitializedEntity & Parent)3242 InitializedEntity::InitializedEntity(ASTContext &Context, unsigned Index,
3243 const InitializedEntity &Parent)
3244 : Parent(&Parent), Index(Index)
3245 {
3246 if (const ArrayType *AT = Context.getAsArrayType(Parent.getType())) {
3247 Kind = EK_ArrayElement;
3248 Type = AT->getElementType();
3249 } else if (const VectorType *VT = Parent.getType()->getAs<VectorType>()) {
3250 Kind = EK_VectorElement;
3251 Type = VT->getElementType();
3252 } else {
3253 const ComplexType *CT = Parent.getType()->getAs<ComplexType>();
3254 assert(CT && "Unexpected type");
3255 Kind = EK_ComplexElement;
3256 Type = CT->getElementType();
3257 }
3258 }
3259
3260 InitializedEntity
InitializeBase(ASTContext & Context,const CXXBaseSpecifier * Base,bool IsInheritedVirtualBase,const InitializedEntity * Parent)3261 InitializedEntity::InitializeBase(ASTContext &Context,
3262 const CXXBaseSpecifier *Base,
3263 bool IsInheritedVirtualBase,
3264 const InitializedEntity *Parent) {
3265 InitializedEntity Result;
3266 Result.Kind = EK_Base;
3267 Result.Parent = Parent;
3268 Result.Base = reinterpret_cast<uintptr_t>(Base);
3269 if (IsInheritedVirtualBase)
3270 Result.Base |= 0x01;
3271
3272 Result.Type = Base->getType();
3273 return Result;
3274 }
3275
getName() const3276 DeclarationName InitializedEntity::getName() const {
3277 switch (getKind()) {
3278 case EK_Parameter:
3279 case EK_Parameter_CF_Audited: {
3280 ParmVarDecl *D = reinterpret_cast<ParmVarDecl*>(Parameter & ~0x1);
3281 return (D ? D->getDeclName() : DeclarationName());
3282 }
3283
3284 case EK_Variable:
3285 case EK_Member:
3286 case EK_Binding:
3287 case EK_TemplateParameter:
3288 return Variable.VariableOrMember->getDeclName();
3289
3290 case EK_LambdaCapture:
3291 return DeclarationName(Capture.VarID);
3292
3293 case EK_Result:
3294 case EK_StmtExprResult:
3295 case EK_Exception:
3296 case EK_New:
3297 case EK_Temporary:
3298 case EK_Base:
3299 case EK_Delegating:
3300 case EK_ArrayElement:
3301 case EK_VectorElement:
3302 case EK_ComplexElement:
3303 case EK_BlockElement:
3304 case EK_LambdaToBlockConversionBlockElement:
3305 case EK_CompoundLiteralInit:
3306 case EK_RelatedResult:
3307 return DeclarationName();
3308 }
3309
3310 llvm_unreachable("Invalid EntityKind!");
3311 }
3312
getDecl() const3313 ValueDecl *InitializedEntity::getDecl() const {
3314 switch (getKind()) {
3315 case EK_Variable:
3316 case EK_Member:
3317 case EK_Binding:
3318 case EK_TemplateParameter:
3319 return Variable.VariableOrMember;
3320
3321 case EK_Parameter:
3322 case EK_Parameter_CF_Audited:
3323 return reinterpret_cast<ParmVarDecl*>(Parameter & ~0x1);
3324
3325 case EK_Result:
3326 case EK_StmtExprResult:
3327 case EK_Exception:
3328 case EK_New:
3329 case EK_Temporary:
3330 case EK_Base:
3331 case EK_Delegating:
3332 case EK_ArrayElement:
3333 case EK_VectorElement:
3334 case EK_ComplexElement:
3335 case EK_BlockElement:
3336 case EK_LambdaToBlockConversionBlockElement:
3337 case EK_LambdaCapture:
3338 case EK_CompoundLiteralInit:
3339 case EK_RelatedResult:
3340 return nullptr;
3341 }
3342
3343 llvm_unreachable("Invalid EntityKind!");
3344 }
3345
allowsNRVO() const3346 bool InitializedEntity::allowsNRVO() const {
3347 switch (getKind()) {
3348 case EK_Result:
3349 case EK_Exception:
3350 return LocAndNRVO.NRVO;
3351
3352 case EK_StmtExprResult:
3353 case EK_Variable:
3354 case EK_Parameter:
3355 case EK_Parameter_CF_Audited:
3356 case EK_TemplateParameter:
3357 case EK_Member:
3358 case EK_Binding:
3359 case EK_New:
3360 case EK_Temporary:
3361 case EK_CompoundLiteralInit:
3362 case EK_Base:
3363 case EK_Delegating:
3364 case EK_ArrayElement:
3365 case EK_VectorElement:
3366 case EK_ComplexElement:
3367 case EK_BlockElement:
3368 case EK_LambdaToBlockConversionBlockElement:
3369 case EK_LambdaCapture:
3370 case EK_RelatedResult:
3371 break;
3372 }
3373
3374 return false;
3375 }
3376
dumpImpl(raw_ostream & OS) const3377 unsigned InitializedEntity::dumpImpl(raw_ostream &OS) const {
3378 assert(getParent() != this);
3379 unsigned Depth = getParent() ? getParent()->dumpImpl(OS) : 0;
3380 for (unsigned I = 0; I != Depth; ++I)
3381 OS << "`-";
3382
3383 switch (getKind()) {
3384 case EK_Variable: OS << "Variable"; break;
3385 case EK_Parameter: OS << "Parameter"; break;
3386 case EK_Parameter_CF_Audited: OS << "CF audited function Parameter";
3387 break;
3388 case EK_TemplateParameter: OS << "TemplateParameter"; break;
3389 case EK_Result: OS << "Result"; break;
3390 case EK_StmtExprResult: OS << "StmtExprResult"; break;
3391 case EK_Exception: OS << "Exception"; break;
3392 case EK_Member: OS << "Member"; break;
3393 case EK_Binding: OS << "Binding"; break;
3394 case EK_New: OS << "New"; break;
3395 case EK_Temporary: OS << "Temporary"; break;
3396 case EK_CompoundLiteralInit: OS << "CompoundLiteral";break;
3397 case EK_RelatedResult: OS << "RelatedResult"; break;
3398 case EK_Base: OS << "Base"; break;
3399 case EK_Delegating: OS << "Delegating"; break;
3400 case EK_ArrayElement: OS << "ArrayElement " << Index; break;
3401 case EK_VectorElement: OS << "VectorElement " << Index; break;
3402 case EK_ComplexElement: OS << "ComplexElement " << Index; break;
3403 case EK_BlockElement: OS << "Block"; break;
3404 case EK_LambdaToBlockConversionBlockElement:
3405 OS << "Block (lambda)";
3406 break;
3407 case EK_LambdaCapture:
3408 OS << "LambdaCapture ";
3409 OS << DeclarationName(Capture.VarID);
3410 break;
3411 }
3412
3413 if (auto *D = getDecl()) {
3414 OS << " ";
3415 D->printQualifiedName(OS);
3416 }
3417
3418 OS << " '" << getType().getAsString() << "'\n";
3419
3420 return Depth + 1;
3421 }
3422
dump() const3423 LLVM_DUMP_METHOD void InitializedEntity::dump() const {
3424 dumpImpl(llvm::errs());
3425 }
3426
3427 //===----------------------------------------------------------------------===//
3428 // Initialization sequence
3429 //===----------------------------------------------------------------------===//
3430
Destroy()3431 void InitializationSequence::Step::Destroy() {
3432 switch (Kind) {
3433 case SK_ResolveAddressOfOverloadedFunction:
3434 case SK_CastDerivedToBaseRValue:
3435 case SK_CastDerivedToBaseXValue:
3436 case SK_CastDerivedToBaseLValue:
3437 case SK_BindReference:
3438 case SK_BindReferenceToTemporary:
3439 case SK_FinalCopy:
3440 case SK_ExtraneousCopyToTemporary:
3441 case SK_UserConversion:
3442 case SK_QualificationConversionRValue:
3443 case SK_QualificationConversionXValue:
3444 case SK_QualificationConversionLValue:
3445 case SK_AtomicConversion:
3446 case SK_ListInitialization:
3447 case SK_UnwrapInitList:
3448 case SK_RewrapInitList:
3449 case SK_ConstructorInitialization:
3450 case SK_ConstructorInitializationFromList:
3451 case SK_ZeroInitialization:
3452 case SK_CAssignment:
3453 case SK_StringInit:
3454 case SK_ObjCObjectConversion:
3455 case SK_ArrayLoopIndex:
3456 case SK_ArrayLoopInit:
3457 case SK_ArrayInit:
3458 case SK_GNUArrayInit:
3459 case SK_ParenthesizedArrayInit:
3460 case SK_PassByIndirectCopyRestore:
3461 case SK_PassByIndirectRestore:
3462 case SK_ProduceObjCObject:
3463 case SK_StdInitializerList:
3464 case SK_StdInitializerListConstructorCall:
3465 case SK_OCLSamplerInit:
3466 case SK_OCLZeroOpaqueType:
3467 break;
3468
3469 case SK_ConversionSequence:
3470 case SK_ConversionSequenceNoNarrowing:
3471 delete ICS;
3472 }
3473 }
3474
isDirectReferenceBinding() const3475 bool InitializationSequence::isDirectReferenceBinding() const {
3476 // There can be some lvalue adjustments after the SK_BindReference step.
3477 for (auto I = Steps.rbegin(); I != Steps.rend(); ++I) {
3478 if (I->Kind == SK_BindReference)
3479 return true;
3480 if (I->Kind == SK_BindReferenceToTemporary)
3481 return false;
3482 }
3483 return false;
3484 }
3485
isAmbiguous() const3486 bool InitializationSequence::isAmbiguous() const {
3487 if (!Failed())
3488 return false;
3489
3490 switch (getFailureKind()) {
3491 case FK_TooManyInitsForReference:
3492 case FK_ParenthesizedListInitForReference:
3493 case FK_ArrayNeedsInitList:
3494 case FK_ArrayNeedsInitListOrStringLiteral:
3495 case FK_ArrayNeedsInitListOrWideStringLiteral:
3496 case FK_NarrowStringIntoWideCharArray:
3497 case FK_WideStringIntoCharArray:
3498 case FK_IncompatWideStringIntoWideChar:
3499 case FK_PlainStringIntoUTF8Char:
3500 case FK_UTF8StringIntoPlainChar:
3501 case FK_AddressOfOverloadFailed: // FIXME: Could do better
3502 case FK_NonConstLValueReferenceBindingToTemporary:
3503 case FK_NonConstLValueReferenceBindingToBitfield:
3504 case FK_NonConstLValueReferenceBindingToVectorElement:
3505 case FK_NonConstLValueReferenceBindingToMatrixElement:
3506 case FK_NonConstLValueReferenceBindingToUnrelated:
3507 case FK_RValueReferenceBindingToLValue:
3508 case FK_ReferenceAddrspaceMismatchTemporary:
3509 case FK_ReferenceInitDropsQualifiers:
3510 case FK_ReferenceInitFailed:
3511 case FK_ConversionFailed:
3512 case FK_ConversionFromPropertyFailed:
3513 case FK_TooManyInitsForScalar:
3514 case FK_ParenthesizedListInitForScalar:
3515 case FK_ReferenceBindingToInitList:
3516 case FK_InitListBadDestinationType:
3517 case FK_DefaultInitOfConst:
3518 case FK_Incomplete:
3519 case FK_ArrayTypeMismatch:
3520 case FK_NonConstantArrayInit:
3521 case FK_ListInitializationFailed:
3522 case FK_VariableLengthArrayHasInitializer:
3523 case FK_PlaceholderType:
3524 case FK_ExplicitConstructor:
3525 case FK_AddressOfUnaddressableFunction:
3526 return false;
3527
3528 case FK_ReferenceInitOverloadFailed:
3529 case FK_UserConversionOverloadFailed:
3530 case FK_ConstructorOverloadFailed:
3531 case FK_ListConstructorOverloadFailed:
3532 return FailedOverloadResult == OR_Ambiguous;
3533 }
3534
3535 llvm_unreachable("Invalid EntityKind!");
3536 }
3537
isConstructorInitialization() const3538 bool InitializationSequence::isConstructorInitialization() const {
3539 return !Steps.empty() && Steps.back().Kind == SK_ConstructorInitialization;
3540 }
3541
3542 void
3543 InitializationSequence
AddAddressOverloadResolutionStep(FunctionDecl * Function,DeclAccessPair Found,bool HadMultipleCandidates)3544 ::AddAddressOverloadResolutionStep(FunctionDecl *Function,
3545 DeclAccessPair Found,
3546 bool HadMultipleCandidates) {
3547 Step S;
3548 S.Kind = SK_ResolveAddressOfOverloadedFunction;
3549 S.Type = Function->getType();
3550 S.Function.HadMultipleCandidates = HadMultipleCandidates;
3551 S.Function.Function = Function;
3552 S.Function.FoundDecl = Found;
3553 Steps.push_back(S);
3554 }
3555
AddDerivedToBaseCastStep(QualType BaseType,ExprValueKind VK)3556 void InitializationSequence::AddDerivedToBaseCastStep(QualType BaseType,
3557 ExprValueKind VK) {
3558 Step S;
3559 switch (VK) {
3560 case VK_RValue: S.Kind = SK_CastDerivedToBaseRValue; break;
3561 case VK_XValue: S.Kind = SK_CastDerivedToBaseXValue; break;
3562 case VK_LValue: S.Kind = SK_CastDerivedToBaseLValue; break;
3563 }
3564 S.Type = BaseType;
3565 Steps.push_back(S);
3566 }
3567
AddReferenceBindingStep(QualType T,bool BindingTemporary)3568 void InitializationSequence::AddReferenceBindingStep(QualType T,
3569 bool BindingTemporary) {
3570 Step S;
3571 S.Kind = BindingTemporary? SK_BindReferenceToTemporary : SK_BindReference;
3572 S.Type = T;
3573 Steps.push_back(S);
3574 }
3575
AddFinalCopy(QualType T)3576 void InitializationSequence::AddFinalCopy(QualType T) {
3577 Step S;
3578 S.Kind = SK_FinalCopy;
3579 S.Type = T;
3580 Steps.push_back(S);
3581 }
3582
AddExtraneousCopyToTemporary(QualType T)3583 void InitializationSequence::AddExtraneousCopyToTemporary(QualType T) {
3584 Step S;
3585 S.Kind = SK_ExtraneousCopyToTemporary;
3586 S.Type = T;
3587 Steps.push_back(S);
3588 }
3589
3590 void
AddUserConversionStep(FunctionDecl * Function,DeclAccessPair FoundDecl,QualType T,bool HadMultipleCandidates)3591 InitializationSequence::AddUserConversionStep(FunctionDecl *Function,
3592 DeclAccessPair FoundDecl,
3593 QualType T,
3594 bool HadMultipleCandidates) {
3595 Step S;
3596 S.Kind = SK_UserConversion;
3597 S.Type = T;
3598 S.Function.HadMultipleCandidates = HadMultipleCandidates;
3599 S.Function.Function = Function;
3600 S.Function.FoundDecl = FoundDecl;
3601 Steps.push_back(S);
3602 }
3603
AddQualificationConversionStep(QualType Ty,ExprValueKind VK)3604 void InitializationSequence::AddQualificationConversionStep(QualType Ty,
3605 ExprValueKind VK) {
3606 Step S;
3607 S.Kind = SK_QualificationConversionRValue; // work around a gcc warning
3608 switch (VK) {
3609 case VK_RValue:
3610 S.Kind = SK_QualificationConversionRValue;
3611 break;
3612 case VK_XValue:
3613 S.Kind = SK_QualificationConversionXValue;
3614 break;
3615 case VK_LValue:
3616 S.Kind = SK_QualificationConversionLValue;
3617 break;
3618 }
3619 S.Type = Ty;
3620 Steps.push_back(S);
3621 }
3622
AddAtomicConversionStep(QualType Ty)3623 void InitializationSequence::AddAtomicConversionStep(QualType Ty) {
3624 Step S;
3625 S.Kind = SK_AtomicConversion;
3626 S.Type = Ty;
3627 Steps.push_back(S);
3628 }
3629
AddConversionSequenceStep(const ImplicitConversionSequence & ICS,QualType T,bool TopLevelOfInitList)3630 void InitializationSequence::AddConversionSequenceStep(
3631 const ImplicitConversionSequence &ICS, QualType T,
3632 bool TopLevelOfInitList) {
3633 Step S;
3634 S.Kind = TopLevelOfInitList ? SK_ConversionSequenceNoNarrowing
3635 : SK_ConversionSequence;
3636 S.Type = T;
3637 S.ICS = new ImplicitConversionSequence(ICS);
3638 Steps.push_back(S);
3639 }
3640
AddListInitializationStep(QualType T)3641 void InitializationSequence::AddListInitializationStep(QualType T) {
3642 Step S;
3643 S.Kind = SK_ListInitialization;
3644 S.Type = T;
3645 Steps.push_back(S);
3646 }
3647
AddConstructorInitializationStep(DeclAccessPair FoundDecl,CXXConstructorDecl * Constructor,QualType T,bool HadMultipleCandidates,bool FromInitList,bool AsInitList)3648 void InitializationSequence::AddConstructorInitializationStep(
3649 DeclAccessPair FoundDecl, CXXConstructorDecl *Constructor, QualType T,
3650 bool HadMultipleCandidates, bool FromInitList, bool AsInitList) {
3651 Step S;
3652 S.Kind = FromInitList ? AsInitList ? SK_StdInitializerListConstructorCall
3653 : SK_ConstructorInitializationFromList
3654 : SK_ConstructorInitialization;
3655 S.Type = T;
3656 S.Function.HadMultipleCandidates = HadMultipleCandidates;
3657 S.Function.Function = Constructor;
3658 S.Function.FoundDecl = FoundDecl;
3659 Steps.push_back(S);
3660 }
3661
AddZeroInitializationStep(QualType T)3662 void InitializationSequence::AddZeroInitializationStep(QualType T) {
3663 Step S;
3664 S.Kind = SK_ZeroInitialization;
3665 S.Type = T;
3666 Steps.push_back(S);
3667 }
3668
AddCAssignmentStep(QualType T)3669 void InitializationSequence::AddCAssignmentStep(QualType T) {
3670 Step S;
3671 S.Kind = SK_CAssignment;
3672 S.Type = T;
3673 Steps.push_back(S);
3674 }
3675
AddStringInitStep(QualType T)3676 void InitializationSequence::AddStringInitStep(QualType T) {
3677 Step S;
3678 S.Kind = SK_StringInit;
3679 S.Type = T;
3680 Steps.push_back(S);
3681 }
3682
AddObjCObjectConversionStep(QualType T)3683 void InitializationSequence::AddObjCObjectConversionStep(QualType T) {
3684 Step S;
3685 S.Kind = SK_ObjCObjectConversion;
3686 S.Type = T;
3687 Steps.push_back(S);
3688 }
3689
AddArrayInitStep(QualType T,bool IsGNUExtension)3690 void InitializationSequence::AddArrayInitStep(QualType T, bool IsGNUExtension) {
3691 Step S;
3692 S.Kind = IsGNUExtension ? SK_GNUArrayInit : SK_ArrayInit;
3693 S.Type = T;
3694 Steps.push_back(S);
3695 }
3696
AddArrayInitLoopStep(QualType T,QualType EltT)3697 void InitializationSequence::AddArrayInitLoopStep(QualType T, QualType EltT) {
3698 Step S;
3699 S.Kind = SK_ArrayLoopIndex;
3700 S.Type = EltT;
3701 Steps.insert(Steps.begin(), S);
3702
3703 S.Kind = SK_ArrayLoopInit;
3704 S.Type = T;
3705 Steps.push_back(S);
3706 }
3707
AddParenthesizedArrayInitStep(QualType T)3708 void InitializationSequence::AddParenthesizedArrayInitStep(QualType T) {
3709 Step S;
3710 S.Kind = SK_ParenthesizedArrayInit;
3711 S.Type = T;
3712 Steps.push_back(S);
3713 }
3714
AddPassByIndirectCopyRestoreStep(QualType type,bool shouldCopy)3715 void InitializationSequence::AddPassByIndirectCopyRestoreStep(QualType type,
3716 bool shouldCopy) {
3717 Step s;
3718 s.Kind = (shouldCopy ? SK_PassByIndirectCopyRestore
3719 : SK_PassByIndirectRestore);
3720 s.Type = type;
3721 Steps.push_back(s);
3722 }
3723
AddProduceObjCObjectStep(QualType T)3724 void InitializationSequence::AddProduceObjCObjectStep(QualType T) {
3725 Step S;
3726 S.Kind = SK_ProduceObjCObject;
3727 S.Type = T;
3728 Steps.push_back(S);
3729 }
3730
AddStdInitializerListConstructionStep(QualType T)3731 void InitializationSequence::AddStdInitializerListConstructionStep(QualType T) {
3732 Step S;
3733 S.Kind = SK_StdInitializerList;
3734 S.Type = T;
3735 Steps.push_back(S);
3736 }
3737
AddOCLSamplerInitStep(QualType T)3738 void InitializationSequence::AddOCLSamplerInitStep(QualType T) {
3739 Step S;
3740 S.Kind = SK_OCLSamplerInit;
3741 S.Type = T;
3742 Steps.push_back(S);
3743 }
3744
AddOCLZeroOpaqueTypeStep(QualType T)3745 void InitializationSequence::AddOCLZeroOpaqueTypeStep(QualType T) {
3746 Step S;
3747 S.Kind = SK_OCLZeroOpaqueType;
3748 S.Type = T;
3749 Steps.push_back(S);
3750 }
3751
RewrapReferenceInitList(QualType T,InitListExpr * Syntactic)3752 void InitializationSequence::RewrapReferenceInitList(QualType T,
3753 InitListExpr *Syntactic) {
3754 assert(Syntactic->getNumInits() == 1 &&
3755 "Can only rewrap trivial init lists.");
3756 Step S;
3757 S.Kind = SK_UnwrapInitList;
3758 S.Type = Syntactic->getInit(0)->getType();
3759 Steps.insert(Steps.begin(), S);
3760
3761 S.Kind = SK_RewrapInitList;
3762 S.Type = T;
3763 S.WrappingSyntacticList = Syntactic;
3764 Steps.push_back(S);
3765 }
3766
SetOverloadFailure(FailureKind Failure,OverloadingResult Result)3767 void InitializationSequence::SetOverloadFailure(FailureKind Failure,
3768 OverloadingResult Result) {
3769 setSequenceKind(FailedSequence);
3770 this->Failure = Failure;
3771 this->FailedOverloadResult = Result;
3772 }
3773
3774 //===----------------------------------------------------------------------===//
3775 // Attempt initialization
3776 //===----------------------------------------------------------------------===//
3777
3778 /// Tries to add a zero initializer. Returns true if that worked.
3779 static bool
maybeRecoverWithZeroInitialization(Sema & S,InitializationSequence & Sequence,const InitializedEntity & Entity)3780 maybeRecoverWithZeroInitialization(Sema &S, InitializationSequence &Sequence,
3781 const InitializedEntity &Entity) {
3782 if (Entity.getKind() != InitializedEntity::EK_Variable)
3783 return false;
3784
3785 VarDecl *VD = cast<VarDecl>(Entity.getDecl());
3786 if (VD->getInit() || VD->getEndLoc().isMacroID())
3787 return false;
3788
3789 QualType VariableTy = VD->getType().getCanonicalType();
3790 SourceLocation Loc = S.getLocForEndOfToken(VD->getEndLoc());
3791 std::string Init = S.getFixItZeroInitializerForType(VariableTy, Loc);
3792 if (!Init.empty()) {
3793 Sequence.AddZeroInitializationStep(Entity.getType());
3794 Sequence.SetZeroInitializationFixit(Init, Loc);
3795 return true;
3796 }
3797 return false;
3798 }
3799
MaybeProduceObjCObject(Sema & S,InitializationSequence & Sequence,const InitializedEntity & Entity)3800 static void MaybeProduceObjCObject(Sema &S,
3801 InitializationSequence &Sequence,
3802 const InitializedEntity &Entity) {
3803 if (!S.getLangOpts().ObjCAutoRefCount) return;
3804
3805 /// When initializing a parameter, produce the value if it's marked
3806 /// __attribute__((ns_consumed)).
3807 if (Entity.isParameterKind()) {
3808 if (!Entity.isParameterConsumed())
3809 return;
3810
3811 assert(Entity.getType()->isObjCRetainableType() &&
3812 "consuming an object of unretainable type?");
3813 Sequence.AddProduceObjCObjectStep(Entity.getType());
3814
3815 /// When initializing a return value, if the return type is a
3816 /// retainable type, then returns need to immediately retain the
3817 /// object. If an autorelease is required, it will be done at the
3818 /// last instant.
3819 } else if (Entity.getKind() == InitializedEntity::EK_Result ||
3820 Entity.getKind() == InitializedEntity::EK_StmtExprResult) {
3821 if (!Entity.getType()->isObjCRetainableType())
3822 return;
3823
3824 Sequence.AddProduceObjCObjectStep(Entity.getType());
3825 }
3826 }
3827
3828 static void TryListInitialization(Sema &S,
3829 const InitializedEntity &Entity,
3830 const InitializationKind &Kind,
3831 InitListExpr *InitList,
3832 InitializationSequence &Sequence,
3833 bool TreatUnavailableAsInvalid);
3834
3835 /// When initializing from init list via constructor, handle
3836 /// initialization of an object of type std::initializer_list<T>.
3837 ///
3838 /// \return true if we have handled initialization of an object of type
3839 /// std::initializer_list<T>, false otherwise.
TryInitializerListConstruction(Sema & S,InitListExpr * List,QualType DestType,InitializationSequence & Sequence,bool TreatUnavailableAsInvalid)3840 static bool TryInitializerListConstruction(Sema &S,
3841 InitListExpr *List,
3842 QualType DestType,
3843 InitializationSequence &Sequence,
3844 bool TreatUnavailableAsInvalid) {
3845 QualType E;
3846 if (!S.isStdInitializerList(DestType, &E))
3847 return false;
3848
3849 if (!S.isCompleteType(List->getExprLoc(), E)) {
3850 Sequence.setIncompleteTypeFailure(E);
3851 return true;
3852 }
3853
3854 // Try initializing a temporary array from the init list.
3855 QualType ArrayType = S.Context.getConstantArrayType(
3856 E.withConst(),
3857 llvm::APInt(S.Context.getTypeSize(S.Context.getSizeType()),
3858 List->getNumInits()),
3859 nullptr, clang::ArrayType::Normal, 0);
3860 InitializedEntity HiddenArray =
3861 InitializedEntity::InitializeTemporary(ArrayType);
3862 InitializationKind Kind = InitializationKind::CreateDirectList(
3863 List->getExprLoc(), List->getBeginLoc(), List->getEndLoc());
3864 TryListInitialization(S, HiddenArray, Kind, List, Sequence,
3865 TreatUnavailableAsInvalid);
3866 if (Sequence)
3867 Sequence.AddStdInitializerListConstructionStep(DestType);
3868 return true;
3869 }
3870
3871 /// Determine if the constructor has the signature of a copy or move
3872 /// constructor for the type T of the class in which it was found. That is,
3873 /// determine if its first parameter is of type T or reference to (possibly
3874 /// cv-qualified) T.
hasCopyOrMoveCtorParam(ASTContext & Ctx,const ConstructorInfo & Info)3875 static bool hasCopyOrMoveCtorParam(ASTContext &Ctx,
3876 const ConstructorInfo &Info) {
3877 if (Info.Constructor->getNumParams() == 0)
3878 return false;
3879
3880 QualType ParmT =
3881 Info.Constructor->getParamDecl(0)->getType().getNonReferenceType();
3882 QualType ClassT =
3883 Ctx.getRecordType(cast<CXXRecordDecl>(Info.FoundDecl->getDeclContext()));
3884
3885 return Ctx.hasSameUnqualifiedType(ParmT, ClassT);
3886 }
3887
3888 static OverloadingResult
ResolveConstructorOverload(Sema & S,SourceLocation DeclLoc,MultiExprArg Args,OverloadCandidateSet & CandidateSet,QualType DestType,DeclContext::lookup_result Ctors,OverloadCandidateSet::iterator & Best,bool CopyInitializing,bool AllowExplicit,bool OnlyListConstructors,bool IsListInit,bool SecondStepOfCopyInit=false)3889 ResolveConstructorOverload(Sema &S, SourceLocation DeclLoc,
3890 MultiExprArg Args,
3891 OverloadCandidateSet &CandidateSet,
3892 QualType DestType,
3893 DeclContext::lookup_result Ctors,
3894 OverloadCandidateSet::iterator &Best,
3895 bool CopyInitializing, bool AllowExplicit,
3896 bool OnlyListConstructors, bool IsListInit,
3897 bool SecondStepOfCopyInit = false) {
3898 CandidateSet.clear(OverloadCandidateSet::CSK_InitByConstructor);
3899 CandidateSet.setDestAS(DestType.getQualifiers().getAddressSpace());
3900
3901 for (NamedDecl *D : Ctors) {
3902 auto Info = getConstructorInfo(D);
3903 if (!Info.Constructor || Info.Constructor->isInvalidDecl())
3904 continue;
3905
3906 if (OnlyListConstructors && !S.isInitListConstructor(Info.Constructor))
3907 continue;
3908
3909 // C++11 [over.best.ics]p4:
3910 // ... and the constructor or user-defined conversion function is a
3911 // candidate by
3912 // - 13.3.1.3, when the argument is the temporary in the second step
3913 // of a class copy-initialization, or
3914 // - 13.3.1.4, 13.3.1.5, or 13.3.1.6 (in all cases), [not handled here]
3915 // - the second phase of 13.3.1.7 when the initializer list has exactly
3916 // one element that is itself an initializer list, and the target is
3917 // the first parameter of a constructor of class X, and the conversion
3918 // is to X or reference to (possibly cv-qualified X),
3919 // user-defined conversion sequences are not considered.
3920 bool SuppressUserConversions =
3921 SecondStepOfCopyInit ||
3922 (IsListInit && Args.size() == 1 && isa<InitListExpr>(Args[0]) &&
3923 hasCopyOrMoveCtorParam(S.Context, Info));
3924
3925 if (Info.ConstructorTmpl)
3926 S.AddTemplateOverloadCandidate(
3927 Info.ConstructorTmpl, Info.FoundDecl,
3928 /*ExplicitArgs*/ nullptr, Args, CandidateSet, SuppressUserConversions,
3929 /*PartialOverloading=*/false, AllowExplicit);
3930 else {
3931 // C++ [over.match.copy]p1:
3932 // - When initializing a temporary to be bound to the first parameter
3933 // of a constructor [for type T] that takes a reference to possibly
3934 // cv-qualified T as its first argument, called with a single
3935 // argument in the context of direct-initialization, explicit
3936 // conversion functions are also considered.
3937 // FIXME: What if a constructor template instantiates to such a signature?
3938 bool AllowExplicitConv = AllowExplicit && !CopyInitializing &&
3939 Args.size() == 1 &&
3940 hasCopyOrMoveCtorParam(S.Context, Info);
3941 S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, Args,
3942 CandidateSet, SuppressUserConversions,
3943 /*PartialOverloading=*/false, AllowExplicit,
3944 AllowExplicitConv);
3945 }
3946 }
3947
3948 // FIXME: Work around a bug in C++17 guaranteed copy elision.
3949 //
3950 // When initializing an object of class type T by constructor
3951 // ([over.match.ctor]) or by list-initialization ([over.match.list])
3952 // from a single expression of class type U, conversion functions of
3953 // U that convert to the non-reference type cv T are candidates.
3954 // Explicit conversion functions are only candidates during
3955 // direct-initialization.
3956 //
3957 // Note: SecondStepOfCopyInit is only ever true in this case when
3958 // evaluating whether to produce a C++98 compatibility warning.
3959 if (S.getLangOpts().CPlusPlus17 && Args.size() == 1 &&
3960 !SecondStepOfCopyInit) {
3961 Expr *Initializer = Args[0];
3962 auto *SourceRD = Initializer->getType()->getAsCXXRecordDecl();
3963 if (SourceRD && S.isCompleteType(DeclLoc, Initializer->getType())) {
3964 const auto &Conversions = SourceRD->getVisibleConversionFunctions();
3965 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
3966 NamedDecl *D = *I;
3967 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
3968 D = D->getUnderlyingDecl();
3969
3970 FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
3971 CXXConversionDecl *Conv;
3972 if (ConvTemplate)
3973 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
3974 else
3975 Conv = cast<CXXConversionDecl>(D);
3976
3977 if (ConvTemplate)
3978 S.AddTemplateConversionCandidate(
3979 ConvTemplate, I.getPair(), ActingDC, Initializer, DestType,
3980 CandidateSet, AllowExplicit, AllowExplicit,
3981 /*AllowResultConversion*/ false);
3982 else
3983 S.AddConversionCandidate(Conv, I.getPair(), ActingDC, Initializer,
3984 DestType, CandidateSet, AllowExplicit,
3985 AllowExplicit,
3986 /*AllowResultConversion*/ false);
3987 }
3988 }
3989 }
3990
3991 // Perform overload resolution and return the result.
3992 return CandidateSet.BestViableFunction(S, DeclLoc, Best);
3993 }
3994
3995 /// Attempt initialization by constructor (C++ [dcl.init]), which
3996 /// enumerates the constructors of the initialized entity and performs overload
3997 /// resolution to select the best.
3998 /// \param DestType The destination class type.
3999 /// \param DestArrayType The destination type, which is either DestType or
4000 /// a (possibly multidimensional) array of DestType.
4001 /// \param IsListInit Is this list-initialization?
4002 /// \param IsInitListCopy Is this non-list-initialization resulting from a
4003 /// list-initialization from {x} where x is the same
4004 /// 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)4005 static void TryConstructorInitialization(Sema &S,
4006 const InitializedEntity &Entity,
4007 const InitializationKind &Kind,
4008 MultiExprArg Args, QualType DestType,
4009 QualType DestArrayType,
4010 InitializationSequence &Sequence,
4011 bool IsListInit = false,
4012 bool IsInitListCopy = false) {
4013 assert(((!IsListInit && !IsInitListCopy) ||
4014 (Args.size() == 1 && isa<InitListExpr>(Args[0]))) &&
4015 "IsListInit/IsInitListCopy must come with a single initializer list "
4016 "argument.");
4017 InitListExpr *ILE =
4018 (IsListInit || IsInitListCopy) ? cast<InitListExpr>(Args[0]) : nullptr;
4019 MultiExprArg UnwrappedArgs =
4020 ILE ? MultiExprArg(ILE->getInits(), ILE->getNumInits()) : Args;
4021
4022 // The type we're constructing needs to be complete.
4023 if (!S.isCompleteType(Kind.getLocation(), DestType)) {
4024 Sequence.setIncompleteTypeFailure(DestType);
4025 return;
4026 }
4027
4028 // C++17 [dcl.init]p17:
4029 // - If the initializer expression is a prvalue and the cv-unqualified
4030 // version of the source type is the same class as the class of the
4031 // destination, the initializer expression is used to initialize the
4032 // destination object.
4033 // Per DR (no number yet), this does not apply when initializing a base
4034 // class or delegating to another constructor from a mem-initializer.
4035 // ObjC++: Lambda captured by the block in the lambda to block conversion
4036 // should avoid copy elision.
4037 if (S.getLangOpts().CPlusPlus17 &&
4038 Entity.getKind() != InitializedEntity::EK_Base &&
4039 Entity.getKind() != InitializedEntity::EK_Delegating &&
4040 Entity.getKind() !=
4041 InitializedEntity::EK_LambdaToBlockConversionBlockElement &&
4042 UnwrappedArgs.size() == 1 && UnwrappedArgs[0]->isRValue() &&
4043 S.Context.hasSameUnqualifiedType(UnwrappedArgs[0]->getType(), DestType)) {
4044 // Convert qualifications if necessary.
4045 Sequence.AddQualificationConversionStep(DestType, VK_RValue);
4046 if (ILE)
4047 Sequence.RewrapReferenceInitList(DestType, ILE);
4048 return;
4049 }
4050
4051 const RecordType *DestRecordType = DestType->getAs<RecordType>();
4052 assert(DestRecordType && "Constructor initialization requires record type");
4053 CXXRecordDecl *DestRecordDecl
4054 = cast<CXXRecordDecl>(DestRecordType->getDecl());
4055
4056 // Build the candidate set directly in the initialization sequence
4057 // structure, so that it will persist if we fail.
4058 OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
4059
4060 // Determine whether we are allowed to call explicit constructors or
4061 // explicit conversion operators.
4062 bool AllowExplicit = Kind.AllowExplicit() || IsListInit;
4063 bool CopyInitialization = Kind.getKind() == InitializationKind::IK_Copy;
4064
4065 // - Otherwise, if T is a class type, constructors are considered. The
4066 // applicable constructors are enumerated, and the best one is chosen
4067 // through overload resolution.
4068 DeclContext::lookup_result Ctors = S.LookupConstructors(DestRecordDecl);
4069
4070 OverloadingResult Result = OR_No_Viable_Function;
4071 OverloadCandidateSet::iterator Best;
4072 bool AsInitializerList = false;
4073
4074 // C++11 [over.match.list]p1, per DR1467:
4075 // When objects of non-aggregate type T are list-initialized, such that
4076 // 8.5.4 [dcl.init.list] specifies that overload resolution is performed
4077 // according to the rules in this section, overload resolution selects
4078 // the constructor in two phases:
4079 //
4080 // - Initially, the candidate functions are the initializer-list
4081 // constructors of the class T and the argument list consists of the
4082 // initializer list as a single argument.
4083 if (IsListInit) {
4084 AsInitializerList = true;
4085
4086 // If the initializer list has no elements and T has a default constructor,
4087 // the first phase is omitted.
4088 if (!(UnwrappedArgs.empty() && S.LookupDefaultConstructor(DestRecordDecl)))
4089 Result = ResolveConstructorOverload(S, Kind.getLocation(), Args,
4090 CandidateSet, DestType, Ctors, Best,
4091 CopyInitialization, AllowExplicit,
4092 /*OnlyListConstructors=*/true,
4093 IsListInit);
4094 }
4095
4096 // C++11 [over.match.list]p1:
4097 // - If no viable initializer-list constructor is found, overload resolution
4098 // is performed again, where the candidate functions are all the
4099 // constructors of the class T and the argument list consists of the
4100 // elements of the initializer list.
4101 if (Result == OR_No_Viable_Function) {
4102 AsInitializerList = false;
4103 Result = ResolveConstructorOverload(S, Kind.getLocation(), UnwrappedArgs,
4104 CandidateSet, DestType, Ctors, Best,
4105 CopyInitialization, AllowExplicit,
4106 /*OnlyListConstructors=*/false,
4107 IsListInit);
4108 }
4109 if (Result) {
4110 Sequence.SetOverloadFailure(IsListInit ?
4111 InitializationSequence::FK_ListConstructorOverloadFailed :
4112 InitializationSequence::FK_ConstructorOverloadFailed,
4113 Result);
4114 return;
4115 }
4116
4117 bool HadMultipleCandidates = (CandidateSet.size() > 1);
4118
4119 // In C++17, ResolveConstructorOverload can select a conversion function
4120 // instead of a constructor.
4121 if (auto *CD = dyn_cast<CXXConversionDecl>(Best->Function)) {
4122 // Add the user-defined conversion step that calls the conversion function.
4123 QualType ConvType = CD->getConversionType();
4124 assert(S.Context.hasSameUnqualifiedType(ConvType, DestType) &&
4125 "should not have selected this conversion function");
4126 Sequence.AddUserConversionStep(CD, Best->FoundDecl, ConvType,
4127 HadMultipleCandidates);
4128 if (!S.Context.hasSameType(ConvType, DestType))
4129 Sequence.AddQualificationConversionStep(DestType, VK_RValue);
4130 if (IsListInit)
4131 Sequence.RewrapReferenceInitList(Entity.getType(), ILE);
4132 return;
4133 }
4134
4135 // C++11 [dcl.init]p6:
4136 // If a program calls for the default initialization of an object
4137 // of a const-qualified type T, T shall be a class type with a
4138 // user-provided default constructor.
4139 // C++ core issue 253 proposal:
4140 // If the implicit default constructor initializes all subobjects, no
4141 // initializer should be required.
4142 // The 253 proposal is for example needed to process libstdc++ headers in 5.x.
4143 CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
4144 if (Kind.getKind() == InitializationKind::IK_Default &&
4145 Entity.getType().isConstQualified()) {
4146 if (!CtorDecl->getParent()->allowConstDefaultInit()) {
4147 if (!maybeRecoverWithZeroInitialization(S, Sequence, Entity))
4148 Sequence.SetFailed(InitializationSequence::FK_DefaultInitOfConst);
4149 return;
4150 }
4151 }
4152
4153 // C++11 [over.match.list]p1:
4154 // In copy-list-initialization, if an explicit constructor is chosen, the
4155 // initializer is ill-formed.
4156 if (IsListInit && !Kind.AllowExplicit() && CtorDecl->isExplicit()) {
4157 Sequence.SetFailed(InitializationSequence::FK_ExplicitConstructor);
4158 return;
4159 }
4160
4161 // Add the constructor initialization step. Any cv-qualification conversion is
4162 // subsumed by the initialization.
4163 Sequence.AddConstructorInitializationStep(
4164 Best->FoundDecl, CtorDecl, DestArrayType, HadMultipleCandidates,
4165 IsListInit | IsInitListCopy, AsInitializerList);
4166 }
4167
4168 static bool
ResolveOverloadedFunctionForReferenceBinding(Sema & S,Expr * Initializer,QualType & SourceType,QualType & UnqualifiedSourceType,QualType UnqualifiedTargetType,InitializationSequence & Sequence)4169 ResolveOverloadedFunctionForReferenceBinding(Sema &S,
4170 Expr *Initializer,
4171 QualType &SourceType,
4172 QualType &UnqualifiedSourceType,
4173 QualType UnqualifiedTargetType,
4174 InitializationSequence &Sequence) {
4175 if (S.Context.getCanonicalType(UnqualifiedSourceType) ==
4176 S.Context.OverloadTy) {
4177 DeclAccessPair Found;
4178 bool HadMultipleCandidates = false;
4179 if (FunctionDecl *Fn
4180 = S.ResolveAddressOfOverloadedFunction(Initializer,
4181 UnqualifiedTargetType,
4182 false, Found,
4183 &HadMultipleCandidates)) {
4184 Sequence.AddAddressOverloadResolutionStep(Fn, Found,
4185 HadMultipleCandidates);
4186 SourceType = Fn->getType();
4187 UnqualifiedSourceType = SourceType.getUnqualifiedType();
4188 } else if (!UnqualifiedTargetType->isRecordType()) {
4189 Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
4190 return true;
4191 }
4192 }
4193 return false;
4194 }
4195
4196 static void TryReferenceInitializationCore(Sema &S,
4197 const InitializedEntity &Entity,
4198 const InitializationKind &Kind,
4199 Expr *Initializer,
4200 QualType cv1T1, QualType T1,
4201 Qualifiers T1Quals,
4202 QualType cv2T2, QualType T2,
4203 Qualifiers T2Quals,
4204 InitializationSequence &Sequence);
4205
4206 static void TryValueInitialization(Sema &S,
4207 const InitializedEntity &Entity,
4208 const InitializationKind &Kind,
4209 InitializationSequence &Sequence,
4210 InitListExpr *InitList = nullptr);
4211
4212 /// Attempt list initialization of a reference.
TryReferenceListInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,InitListExpr * InitList,InitializationSequence & Sequence,bool TreatUnavailableAsInvalid)4213 static void TryReferenceListInitialization(Sema &S,
4214 const InitializedEntity &Entity,
4215 const InitializationKind &Kind,
4216 InitListExpr *InitList,
4217 InitializationSequence &Sequence,
4218 bool TreatUnavailableAsInvalid) {
4219 // First, catch C++03 where this isn't possible.
4220 if (!S.getLangOpts().CPlusPlus11) {
4221 Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
4222 return;
4223 }
4224 // Can't reference initialize a compound literal.
4225 if (Entity.getKind() == InitializedEntity::EK_CompoundLiteralInit) {
4226 Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
4227 return;
4228 }
4229
4230 QualType DestType = Entity.getType();
4231 QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
4232 Qualifiers T1Quals;
4233 QualType T1 = S.Context.getUnqualifiedArrayType(cv1T1, T1Quals);
4234
4235 // Reference initialization via an initializer list works thus:
4236 // If the initializer list consists of a single element that is
4237 // reference-related to the referenced type, bind directly to that element
4238 // (possibly creating temporaries).
4239 // Otherwise, initialize a temporary with the initializer list and
4240 // bind to that.
4241 if (InitList->getNumInits() == 1) {
4242 Expr *Initializer = InitList->getInit(0);
4243 QualType cv2T2 = Initializer->getType();
4244 Qualifiers T2Quals;
4245 QualType T2 = S.Context.getUnqualifiedArrayType(cv2T2, T2Quals);
4246
4247 // If this fails, creating a temporary wouldn't work either.
4248 if (ResolveOverloadedFunctionForReferenceBinding(S, Initializer, cv2T2, T2,
4249 T1, Sequence))
4250 return;
4251
4252 SourceLocation DeclLoc = Initializer->getBeginLoc();
4253 Sema::ReferenceCompareResult RefRelationship
4254 = S.CompareReferenceRelationship(DeclLoc, cv1T1, cv2T2);
4255 if (RefRelationship >= Sema::Ref_Related) {
4256 // Try to bind the reference here.
4257 TryReferenceInitializationCore(S, Entity, Kind, Initializer, cv1T1, T1,
4258 T1Quals, cv2T2, T2, T2Quals, Sequence);
4259 if (Sequence)
4260 Sequence.RewrapReferenceInitList(cv1T1, InitList);
4261 return;
4262 }
4263
4264 // Update the initializer if we've resolved an overloaded function.
4265 if (Sequence.step_begin() != Sequence.step_end())
4266 Sequence.RewrapReferenceInitList(cv1T1, InitList);
4267 }
4268
4269 // Not reference-related. Create a temporary and bind to that.
4270 InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(cv1T1);
4271
4272 TryListInitialization(S, TempEntity, Kind, InitList, Sequence,
4273 TreatUnavailableAsInvalid);
4274 if (Sequence) {
4275 if (DestType->isRValueReferenceType() ||
4276 (T1Quals.hasConst() && !T1Quals.hasVolatile()))
4277 Sequence.AddReferenceBindingStep(cv1T1, /*BindingTemporary=*/true);
4278 else
4279 Sequence.SetFailed(
4280 InitializationSequence::FK_NonConstLValueReferenceBindingToTemporary);
4281 }
4282 }
4283
4284 /// Attempt list initialization (C++0x [dcl.init.list])
TryListInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,InitListExpr * InitList,InitializationSequence & Sequence,bool TreatUnavailableAsInvalid)4285 static void TryListInitialization(Sema &S,
4286 const InitializedEntity &Entity,
4287 const InitializationKind &Kind,
4288 InitListExpr *InitList,
4289 InitializationSequence &Sequence,
4290 bool TreatUnavailableAsInvalid) {
4291 QualType DestType = Entity.getType();
4292
4293 // C++ doesn't allow scalar initialization with more than one argument.
4294 // But C99 complex numbers are scalars and it makes sense there.
4295 if (S.getLangOpts().CPlusPlus && DestType->isScalarType() &&
4296 !DestType->isAnyComplexType() && InitList->getNumInits() > 1) {
4297 Sequence.SetFailed(InitializationSequence::FK_TooManyInitsForScalar);
4298 return;
4299 }
4300 if (DestType->isReferenceType()) {
4301 TryReferenceListInitialization(S, Entity, Kind, InitList, Sequence,
4302 TreatUnavailableAsInvalid);
4303 return;
4304 }
4305
4306 if (DestType->isRecordType() &&
4307 !S.isCompleteType(InitList->getBeginLoc(), DestType)) {
4308 Sequence.setIncompleteTypeFailure(DestType);
4309 return;
4310 }
4311
4312 // C++11 [dcl.init.list]p3, per DR1467:
4313 // - If T is a class type and the initializer list has a single element of
4314 // type cv U, where U is T or a class derived from T, the object is
4315 // initialized from that element (by copy-initialization for
4316 // copy-list-initialization, or by direct-initialization for
4317 // direct-list-initialization).
4318 // - Otherwise, if T is a character array and the initializer list has a
4319 // single element that is an appropriately-typed string literal
4320 // (8.5.2 [dcl.init.string]), initialization is performed as described
4321 // in that section.
4322 // - Otherwise, if T is an aggregate, [...] (continue below).
4323 if (S.getLangOpts().CPlusPlus11 && InitList->getNumInits() == 1) {
4324 if (DestType->isRecordType()) {
4325 QualType InitType = InitList->getInit(0)->getType();
4326 if (S.Context.hasSameUnqualifiedType(InitType, DestType) ||
4327 S.IsDerivedFrom(InitList->getBeginLoc(), InitType, DestType)) {
4328 Expr *InitListAsExpr = InitList;
4329 TryConstructorInitialization(S, Entity, Kind, InitListAsExpr, DestType,
4330 DestType, Sequence,
4331 /*InitListSyntax*/false,
4332 /*IsInitListCopy*/true);
4333 return;
4334 }
4335 }
4336 if (const ArrayType *DestAT = S.Context.getAsArrayType(DestType)) {
4337 Expr *SubInit[1] = {InitList->getInit(0)};
4338 if (!isa<VariableArrayType>(DestAT) &&
4339 IsStringInit(SubInit[0], DestAT, S.Context) == SIF_None) {
4340 InitializationKind SubKind =
4341 Kind.getKind() == InitializationKind::IK_DirectList
4342 ? InitializationKind::CreateDirect(Kind.getLocation(),
4343 InitList->getLBraceLoc(),
4344 InitList->getRBraceLoc())
4345 : Kind;
4346 Sequence.InitializeFrom(S, Entity, SubKind, SubInit,
4347 /*TopLevelOfInitList*/ true,
4348 TreatUnavailableAsInvalid);
4349
4350 // TryStringLiteralInitialization() (in InitializeFrom()) will fail if
4351 // the element is not an appropriately-typed string literal, in which
4352 // case we should proceed as in C++11 (below).
4353 if (Sequence) {
4354 Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
4355 return;
4356 }
4357 }
4358 }
4359 }
4360
4361 // C++11 [dcl.init.list]p3:
4362 // - If T is an aggregate, aggregate initialization is performed.
4363 if ((DestType->isRecordType() && !DestType->isAggregateType()) ||
4364 (S.getLangOpts().CPlusPlus11 &&
4365 S.isStdInitializerList(DestType, nullptr))) {
4366 if (S.getLangOpts().CPlusPlus11) {
4367 // - Otherwise, if the initializer list has no elements and T is a
4368 // class type with a default constructor, the object is
4369 // value-initialized.
4370 if (InitList->getNumInits() == 0) {
4371 CXXRecordDecl *RD = DestType->getAsCXXRecordDecl();
4372 if (S.LookupDefaultConstructor(RD)) {
4373 TryValueInitialization(S, Entity, Kind, Sequence, InitList);
4374 return;
4375 }
4376 }
4377
4378 // - Otherwise, if T is a specialization of std::initializer_list<E>,
4379 // an initializer_list object constructed [...]
4380 if (TryInitializerListConstruction(S, InitList, DestType, Sequence,
4381 TreatUnavailableAsInvalid))
4382 return;
4383
4384 // - Otherwise, if T is a class type, constructors are considered.
4385 Expr *InitListAsExpr = InitList;
4386 TryConstructorInitialization(S, Entity, Kind, InitListAsExpr, DestType,
4387 DestType, Sequence, /*InitListSyntax*/true);
4388 } else
4389 Sequence.SetFailed(InitializationSequence::FK_InitListBadDestinationType);
4390 return;
4391 }
4392
4393 if (S.getLangOpts().CPlusPlus && !DestType->isAggregateType() &&
4394 InitList->getNumInits() == 1) {
4395 Expr *E = InitList->getInit(0);
4396
4397 // - Otherwise, if T is an enumeration with a fixed underlying type,
4398 // the initializer-list has a single element v, and the initialization
4399 // is direct-list-initialization, the object is initialized with the
4400 // value T(v); if a narrowing conversion is required to convert v to
4401 // the underlying type of T, the program is ill-formed.
4402 auto *ET = DestType->getAs<EnumType>();
4403 if (S.getLangOpts().CPlusPlus17 &&
4404 Kind.getKind() == InitializationKind::IK_DirectList &&
4405 ET && ET->getDecl()->isFixed() &&
4406 !S.Context.hasSameUnqualifiedType(E->getType(), DestType) &&
4407 (E->getType()->isIntegralOrEnumerationType() ||
4408 E->getType()->isFloatingType())) {
4409 // There are two ways that T(v) can work when T is an enumeration type.
4410 // If there is either an implicit conversion sequence from v to T or
4411 // a conversion function that can convert from v to T, then we use that.
4412 // Otherwise, if v is of integral, enumeration, or floating-point type,
4413 // it is converted to the enumeration type via its underlying type.
4414 // There is no overlap possible between these two cases (except when the
4415 // source value is already of the destination type), and the first
4416 // case is handled by the general case for single-element lists below.
4417 ImplicitConversionSequence ICS;
4418 ICS.setStandard();
4419 ICS.Standard.setAsIdentityConversion();
4420 if (!E->isRValue())
4421 ICS.Standard.First = ICK_Lvalue_To_Rvalue;
4422 // If E is of a floating-point type, then the conversion is ill-formed
4423 // due to narrowing, but go through the motions in order to produce the
4424 // right diagnostic.
4425 ICS.Standard.Second = E->getType()->isFloatingType()
4426 ? ICK_Floating_Integral
4427 : ICK_Integral_Conversion;
4428 ICS.Standard.setFromType(E->getType());
4429 ICS.Standard.setToType(0, E->getType());
4430 ICS.Standard.setToType(1, DestType);
4431 ICS.Standard.setToType(2, DestType);
4432 Sequence.AddConversionSequenceStep(ICS, ICS.Standard.getToType(2),
4433 /*TopLevelOfInitList*/true);
4434 Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
4435 return;
4436 }
4437
4438 // - Otherwise, if the initializer list has a single element of type E
4439 // [...references are handled above...], the object or reference is
4440 // initialized from that element (by copy-initialization for
4441 // copy-list-initialization, or by direct-initialization for
4442 // direct-list-initialization); if a narrowing conversion is required
4443 // to convert the element to T, the program is ill-formed.
4444 //
4445 // Per core-24034, this is direct-initialization if we were performing
4446 // direct-list-initialization and copy-initialization otherwise.
4447 // We can't use InitListChecker for this, because it always performs
4448 // copy-initialization. This only matters if we might use an 'explicit'
4449 // conversion operator, or for the special case conversion of nullptr_t to
4450 // bool, so we only need to handle those cases.
4451 //
4452 // FIXME: Why not do this in all cases?
4453 Expr *Init = InitList->getInit(0);
4454 if (Init->getType()->isRecordType() ||
4455 (Init->getType()->isNullPtrType() && DestType->isBooleanType())) {
4456 InitializationKind SubKind =
4457 Kind.getKind() == InitializationKind::IK_DirectList
4458 ? InitializationKind::CreateDirect(Kind.getLocation(),
4459 InitList->getLBraceLoc(),
4460 InitList->getRBraceLoc())
4461 : Kind;
4462 Expr *SubInit[1] = { Init };
4463 Sequence.InitializeFrom(S, Entity, SubKind, SubInit,
4464 /*TopLevelOfInitList*/true,
4465 TreatUnavailableAsInvalid);
4466 if (Sequence)
4467 Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
4468 return;
4469 }
4470 }
4471
4472 InitListChecker CheckInitList(S, Entity, InitList,
4473 DestType, /*VerifyOnly=*/true, TreatUnavailableAsInvalid);
4474 if (CheckInitList.HadError()) {
4475 Sequence.SetFailed(InitializationSequence::FK_ListInitializationFailed);
4476 return;
4477 }
4478
4479 // Add the list initialization step with the built init list.
4480 Sequence.AddListInitializationStep(DestType);
4481 }
4482
4483 /// Try a reference initialization that involves calling a conversion
4484 /// function.
TryRefInitWithConversionFunction(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,Expr * Initializer,bool AllowRValues,bool IsLValueRef,InitializationSequence & Sequence)4485 static OverloadingResult TryRefInitWithConversionFunction(
4486 Sema &S, const InitializedEntity &Entity, const InitializationKind &Kind,
4487 Expr *Initializer, bool AllowRValues, bool IsLValueRef,
4488 InitializationSequence &Sequence) {
4489 QualType DestType = Entity.getType();
4490 QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
4491 QualType T1 = cv1T1.getUnqualifiedType();
4492 QualType cv2T2 = Initializer->getType();
4493 QualType T2 = cv2T2.getUnqualifiedType();
4494
4495 assert(!S.CompareReferenceRelationship(Initializer->getBeginLoc(), T1, T2) &&
4496 "Must have incompatible references when binding via conversion");
4497
4498 // Build the candidate set directly in the initialization sequence
4499 // structure, so that it will persist if we fail.
4500 OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
4501 CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
4502
4503 // Determine whether we are allowed to call explicit conversion operators.
4504 // Note that none of [over.match.copy], [over.match.conv], nor
4505 // [over.match.ref] permit an explicit constructor to be chosen when
4506 // initializing a reference, not even for direct-initialization.
4507 bool AllowExplicitCtors = false;
4508 bool AllowExplicitConvs = Kind.allowExplicitConversionFunctionsInRefBinding();
4509
4510 const RecordType *T1RecordType = nullptr;
4511 if (AllowRValues && (T1RecordType = T1->getAs<RecordType>()) &&
4512 S.isCompleteType(Kind.getLocation(), T1)) {
4513 // The type we're converting to is a class type. Enumerate its constructors
4514 // to see if there is a suitable conversion.
4515 CXXRecordDecl *T1RecordDecl = cast<CXXRecordDecl>(T1RecordType->getDecl());
4516
4517 for (NamedDecl *D : S.LookupConstructors(T1RecordDecl)) {
4518 auto Info = getConstructorInfo(D);
4519 if (!Info.Constructor)
4520 continue;
4521
4522 if (!Info.Constructor->isInvalidDecl() &&
4523 Info.Constructor->isConvertingConstructor(/*AllowExplicit*/true)) {
4524 if (Info.ConstructorTmpl)
4525 S.AddTemplateOverloadCandidate(
4526 Info.ConstructorTmpl, Info.FoundDecl,
4527 /*ExplicitArgs*/ nullptr, Initializer, CandidateSet,
4528 /*SuppressUserConversions=*/true,
4529 /*PartialOverloading*/ false, AllowExplicitCtors);
4530 else
4531 S.AddOverloadCandidate(
4532 Info.Constructor, Info.FoundDecl, Initializer, CandidateSet,
4533 /*SuppressUserConversions=*/true,
4534 /*PartialOverloading*/ false, AllowExplicitCtors);
4535 }
4536 }
4537 }
4538 if (T1RecordType && T1RecordType->getDecl()->isInvalidDecl())
4539 return OR_No_Viable_Function;
4540
4541 const RecordType *T2RecordType = nullptr;
4542 if ((T2RecordType = T2->getAs<RecordType>()) &&
4543 S.isCompleteType(Kind.getLocation(), T2)) {
4544 // The type we're converting from is a class type, enumerate its conversion
4545 // functions.
4546 CXXRecordDecl *T2RecordDecl = cast<CXXRecordDecl>(T2RecordType->getDecl());
4547
4548 const auto &Conversions = T2RecordDecl->getVisibleConversionFunctions();
4549 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
4550 NamedDecl *D = *I;
4551 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
4552 if (isa<UsingShadowDecl>(D))
4553 D = cast<UsingShadowDecl>(D)->getTargetDecl();
4554
4555 FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
4556 CXXConversionDecl *Conv;
4557 if (ConvTemplate)
4558 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
4559 else
4560 Conv = cast<CXXConversionDecl>(D);
4561
4562 // If the conversion function doesn't return a reference type,
4563 // it can't be considered for this conversion unless we're allowed to
4564 // consider rvalues.
4565 // FIXME: Do we need to make sure that we only consider conversion
4566 // candidates with reference-compatible results? That might be needed to
4567 // break recursion.
4568 if ((AllowRValues ||
4569 Conv->getConversionType()->isLValueReferenceType())) {
4570 if (ConvTemplate)
4571 S.AddTemplateConversionCandidate(
4572 ConvTemplate, I.getPair(), ActingDC, Initializer, DestType,
4573 CandidateSet,
4574 /*AllowObjCConversionOnExplicit=*/false, AllowExplicitConvs);
4575 else
4576 S.AddConversionCandidate(
4577 Conv, I.getPair(), ActingDC, Initializer, DestType, CandidateSet,
4578 /*AllowObjCConversionOnExplicit=*/false, AllowExplicitConvs);
4579 }
4580 }
4581 }
4582 if (T2RecordType && T2RecordType->getDecl()->isInvalidDecl())
4583 return OR_No_Viable_Function;
4584
4585 SourceLocation DeclLoc = Initializer->getBeginLoc();
4586
4587 // Perform overload resolution. If it fails, return the failed result.
4588 OverloadCandidateSet::iterator Best;
4589 if (OverloadingResult Result
4590 = CandidateSet.BestViableFunction(S, DeclLoc, Best))
4591 return Result;
4592
4593 FunctionDecl *Function = Best->Function;
4594 // This is the overload that will be used for this initialization step if we
4595 // use this initialization. Mark it as referenced.
4596 Function->setReferenced();
4597
4598 // Compute the returned type and value kind of the conversion.
4599 QualType cv3T3;
4600 if (isa<CXXConversionDecl>(Function))
4601 cv3T3 = Function->getReturnType();
4602 else
4603 cv3T3 = T1;
4604
4605 ExprValueKind VK = VK_RValue;
4606 if (cv3T3->isLValueReferenceType())
4607 VK = VK_LValue;
4608 else if (const auto *RRef = cv3T3->getAs<RValueReferenceType>())
4609 VK = RRef->getPointeeType()->isFunctionType() ? VK_LValue : VK_XValue;
4610 cv3T3 = cv3T3.getNonLValueExprType(S.Context);
4611
4612 // Add the user-defined conversion step.
4613 bool HadMultipleCandidates = (CandidateSet.size() > 1);
4614 Sequence.AddUserConversionStep(Function, Best->FoundDecl, cv3T3,
4615 HadMultipleCandidates);
4616
4617 // Determine whether we'll need to perform derived-to-base adjustments or
4618 // other conversions.
4619 Sema::ReferenceConversions RefConv;
4620 Sema::ReferenceCompareResult NewRefRelationship =
4621 S.CompareReferenceRelationship(DeclLoc, T1, cv3T3, &RefConv);
4622
4623 // Add the final conversion sequence, if necessary.
4624 if (NewRefRelationship == Sema::Ref_Incompatible) {
4625 assert(!isa<CXXConstructorDecl>(Function) &&
4626 "should not have conversion after constructor");
4627
4628 ImplicitConversionSequence ICS;
4629 ICS.setStandard();
4630 ICS.Standard = Best->FinalConversion;
4631 Sequence.AddConversionSequenceStep(ICS, ICS.Standard.getToType(2));
4632
4633 // Every implicit conversion results in a prvalue, except for a glvalue
4634 // derived-to-base conversion, which we handle below.
4635 cv3T3 = ICS.Standard.getToType(2);
4636 VK = VK_RValue;
4637 }
4638
4639 // If the converted initializer is a prvalue, its type T4 is adjusted to
4640 // type "cv1 T4" and the temporary materialization conversion is applied.
4641 //
4642 // We adjust the cv-qualifications to match the reference regardless of
4643 // whether we have a prvalue so that the AST records the change. In this
4644 // case, T4 is "cv3 T3".
4645 QualType cv1T4 = S.Context.getQualifiedType(cv3T3, cv1T1.getQualifiers());
4646 if (cv1T4.getQualifiers() != cv3T3.getQualifiers())
4647 Sequence.AddQualificationConversionStep(cv1T4, VK);
4648 Sequence.AddReferenceBindingStep(cv1T4, VK == VK_RValue);
4649 VK = IsLValueRef ? VK_LValue : VK_XValue;
4650
4651 if (RefConv & Sema::ReferenceConversions::DerivedToBase)
4652 Sequence.AddDerivedToBaseCastStep(cv1T1, VK);
4653 else if (RefConv & Sema::ReferenceConversions::ObjC)
4654 Sequence.AddObjCObjectConversionStep(cv1T1);
4655 else if (RefConv & Sema::ReferenceConversions::Function)
4656 Sequence.AddQualificationConversionStep(cv1T1, VK);
4657 else if (RefConv & Sema::ReferenceConversions::Qualification) {
4658 if (!S.Context.hasSameType(cv1T4, cv1T1))
4659 Sequence.AddQualificationConversionStep(cv1T1, VK);
4660 }
4661
4662 return OR_Success;
4663 }
4664
4665 static void CheckCXX98CompatAccessibleCopy(Sema &S,
4666 const InitializedEntity &Entity,
4667 Expr *CurInitExpr);
4668
4669 /// Attempt reference initialization (C++0x [dcl.init.ref])
TryReferenceInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,Expr * Initializer,InitializationSequence & Sequence)4670 static void TryReferenceInitialization(Sema &S,
4671 const InitializedEntity &Entity,
4672 const InitializationKind &Kind,
4673 Expr *Initializer,
4674 InitializationSequence &Sequence) {
4675 QualType DestType = Entity.getType();
4676 QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
4677 Qualifiers T1Quals;
4678 QualType T1 = S.Context.getUnqualifiedArrayType(cv1T1, T1Quals);
4679 QualType cv2T2 = Initializer->getType();
4680 Qualifiers T2Quals;
4681 QualType T2 = S.Context.getUnqualifiedArrayType(cv2T2, T2Quals);
4682
4683 // If the initializer is the address of an overloaded function, try
4684 // to resolve the overloaded function. If all goes well, T2 is the
4685 // type of the resulting function.
4686 if (ResolveOverloadedFunctionForReferenceBinding(S, Initializer, cv2T2, T2,
4687 T1, Sequence))
4688 return;
4689
4690 // Delegate everything else to a subfunction.
4691 TryReferenceInitializationCore(S, Entity, Kind, Initializer, cv1T1, T1,
4692 T1Quals, cv2T2, T2, T2Quals, Sequence);
4693 }
4694
4695 /// Determine whether an expression is a non-referenceable glvalue (one to
4696 /// which a reference can never bind). Attempting to bind a reference to
4697 /// such a glvalue will always create a temporary.
isNonReferenceableGLValue(Expr * E)4698 static bool isNonReferenceableGLValue(Expr *E) {
4699 return E->refersToBitField() || E->refersToVectorElement() ||
4700 E->refersToMatrixElement();
4701 }
4702
4703 /// Reference initialization without resolving overloaded functions.
4704 ///
4705 /// We also can get here in C if we call a builtin which is declared as
4706 /// 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)4707 static void TryReferenceInitializationCore(Sema &S,
4708 const InitializedEntity &Entity,
4709 const InitializationKind &Kind,
4710 Expr *Initializer,
4711 QualType cv1T1, QualType T1,
4712 Qualifiers T1Quals,
4713 QualType cv2T2, QualType T2,
4714 Qualifiers T2Quals,
4715 InitializationSequence &Sequence) {
4716 QualType DestType = Entity.getType();
4717 SourceLocation DeclLoc = Initializer->getBeginLoc();
4718
4719 // Compute some basic properties of the types and the initializer.
4720 bool isLValueRef = DestType->isLValueReferenceType();
4721 bool isRValueRef = !isLValueRef;
4722 Expr::Classification InitCategory = Initializer->Classify(S.Context);
4723
4724 Sema::ReferenceConversions RefConv;
4725 Sema::ReferenceCompareResult RefRelationship =
4726 S.CompareReferenceRelationship(DeclLoc, cv1T1, cv2T2, &RefConv);
4727
4728 // C++0x [dcl.init.ref]p5:
4729 // A reference to type "cv1 T1" is initialized by an expression of type
4730 // "cv2 T2" as follows:
4731 //
4732 // - If the reference is an lvalue reference and the initializer
4733 // expression
4734 // Note the analogous bullet points for rvalue refs to functions. Because
4735 // there are no function rvalues in C++, rvalue refs to functions are treated
4736 // like lvalue refs.
4737 OverloadingResult ConvOvlResult = OR_Success;
4738 bool T1Function = T1->isFunctionType();
4739 if (isLValueRef || T1Function) {
4740 if (InitCategory.isLValue() && !isNonReferenceableGLValue(Initializer) &&
4741 (RefRelationship == Sema::Ref_Compatible ||
4742 (Kind.isCStyleOrFunctionalCast() &&
4743 RefRelationship == Sema::Ref_Related))) {
4744 // - is an lvalue (but is not a bit-field), and "cv1 T1" is
4745 // reference-compatible with "cv2 T2," or
4746 if (RefConv & (Sema::ReferenceConversions::DerivedToBase |
4747 Sema::ReferenceConversions::ObjC)) {
4748 // If we're converting the pointee, add any qualifiers first;
4749 // these qualifiers must all be top-level, so just convert to "cv1 T2".
4750 if (RefConv & (Sema::ReferenceConversions::Qualification))
4751 Sequence.AddQualificationConversionStep(
4752 S.Context.getQualifiedType(T2, T1Quals),
4753 Initializer->getValueKind());
4754 if (RefConv & Sema::ReferenceConversions::DerivedToBase)
4755 Sequence.AddDerivedToBaseCastStep(cv1T1, VK_LValue);
4756 else
4757 Sequence.AddObjCObjectConversionStep(cv1T1);
4758 } else if (RefConv & (Sema::ReferenceConversions::Qualification |
4759 Sema::ReferenceConversions::Function)) {
4760 // Perform a (possibly multi-level) qualification conversion.
4761 // FIXME: Should we use a different step kind for function conversions?
4762 Sequence.AddQualificationConversionStep(cv1T1,
4763 Initializer->getValueKind());
4764 }
4765
4766 // We only create a temporary here when binding a reference to a
4767 // bit-field or vector element. Those cases are't supposed to be
4768 // handled by this bullet, but the outcome is the same either way.
4769 Sequence.AddReferenceBindingStep(cv1T1, false);
4770 return;
4771 }
4772
4773 // - has a class type (i.e., T2 is a class type), where T1 is not
4774 // reference-related to T2, and can be implicitly converted to an
4775 // lvalue of type "cv3 T3," where "cv1 T1" is reference-compatible
4776 // with "cv3 T3" (this conversion is selected by enumerating the
4777 // applicable conversion functions (13.3.1.6) and choosing the best
4778 // one through overload resolution (13.3)),
4779 // If we have an rvalue ref to function type here, the rhs must be
4780 // an rvalue. DR1287 removed the "implicitly" here.
4781 if (RefRelationship == Sema::Ref_Incompatible && T2->isRecordType() &&
4782 (isLValueRef || InitCategory.isRValue())) {
4783 if (S.getLangOpts().CPlusPlus) {
4784 // Try conversion functions only for C++.
4785 ConvOvlResult = TryRefInitWithConversionFunction(
4786 S, Entity, Kind, Initializer, /*AllowRValues*/ isRValueRef,
4787 /*IsLValueRef*/ isLValueRef, Sequence);
4788 if (ConvOvlResult == OR_Success)
4789 return;
4790 if (ConvOvlResult != OR_No_Viable_Function)
4791 Sequence.SetOverloadFailure(
4792 InitializationSequence::FK_ReferenceInitOverloadFailed,
4793 ConvOvlResult);
4794 } else {
4795 ConvOvlResult = OR_No_Viable_Function;
4796 }
4797 }
4798 }
4799
4800 // - Otherwise, the reference shall be an lvalue reference to a
4801 // non-volatile const type (i.e., cv1 shall be const), or the reference
4802 // shall be an rvalue reference.
4803 // For address spaces, we interpret this to mean that an addr space
4804 // of a reference "cv1 T1" is a superset of addr space of "cv2 T2".
4805 if (isLValueRef && !(T1Quals.hasConst() && !T1Quals.hasVolatile() &&
4806 T1Quals.isAddressSpaceSupersetOf(T2Quals))) {
4807 if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy)
4808 Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
4809 else if (ConvOvlResult && !Sequence.getFailedCandidateSet().empty())
4810 Sequence.SetOverloadFailure(
4811 InitializationSequence::FK_ReferenceInitOverloadFailed,
4812 ConvOvlResult);
4813 else if (!InitCategory.isLValue())
4814 Sequence.SetFailed(
4815 T1Quals.isAddressSpaceSupersetOf(T2Quals)
4816 ? InitializationSequence::
4817 FK_NonConstLValueReferenceBindingToTemporary
4818 : InitializationSequence::FK_ReferenceInitDropsQualifiers);
4819 else {
4820 InitializationSequence::FailureKind FK;
4821 switch (RefRelationship) {
4822 case Sema::Ref_Compatible:
4823 if (Initializer->refersToBitField())
4824 FK = InitializationSequence::
4825 FK_NonConstLValueReferenceBindingToBitfield;
4826 else if (Initializer->refersToVectorElement())
4827 FK = InitializationSequence::
4828 FK_NonConstLValueReferenceBindingToVectorElement;
4829 else if (Initializer->refersToMatrixElement())
4830 FK = InitializationSequence::
4831 FK_NonConstLValueReferenceBindingToMatrixElement;
4832 else
4833 llvm_unreachable("unexpected kind of compatible initializer");
4834 break;
4835 case Sema::Ref_Related:
4836 FK = InitializationSequence::FK_ReferenceInitDropsQualifiers;
4837 break;
4838 case Sema::Ref_Incompatible:
4839 FK = InitializationSequence::
4840 FK_NonConstLValueReferenceBindingToUnrelated;
4841 break;
4842 }
4843 Sequence.SetFailed(FK);
4844 }
4845 return;
4846 }
4847
4848 // - If the initializer expression
4849 // - is an
4850 // [<=14] xvalue (but not a bit-field), class prvalue, array prvalue, or
4851 // [1z] rvalue (but not a bit-field) or
4852 // function lvalue and "cv1 T1" is reference-compatible with "cv2 T2"
4853 //
4854 // Note: functions are handled above and below rather than here...
4855 if (!T1Function &&
4856 (RefRelationship == Sema::Ref_Compatible ||
4857 (Kind.isCStyleOrFunctionalCast() &&
4858 RefRelationship == Sema::Ref_Related)) &&
4859 ((InitCategory.isXValue() && !isNonReferenceableGLValue(Initializer)) ||
4860 (InitCategory.isPRValue() &&
4861 (S.getLangOpts().CPlusPlus17 || T2->isRecordType() ||
4862 T2->isArrayType())))) {
4863 ExprValueKind ValueKind = InitCategory.isXValue() ? VK_XValue : VK_RValue;
4864 if (InitCategory.isPRValue() && T2->isRecordType()) {
4865 // The corresponding bullet in C++03 [dcl.init.ref]p5 gives the
4866 // compiler the freedom to perform a copy here or bind to the
4867 // object, while C++0x requires that we bind directly to the
4868 // object. Hence, we always bind to the object without making an
4869 // extra copy. However, in C++03 requires that we check for the
4870 // presence of a suitable copy constructor:
4871 //
4872 // The constructor that would be used to make the copy shall
4873 // be callable whether or not the copy is actually done.
4874 if (!S.getLangOpts().CPlusPlus11 && !S.getLangOpts().MicrosoftExt)
4875 Sequence.AddExtraneousCopyToTemporary(cv2T2);
4876 else if (S.getLangOpts().CPlusPlus11)
4877 CheckCXX98CompatAccessibleCopy(S, Entity, Initializer);
4878 }
4879
4880 // C++1z [dcl.init.ref]/5.2.1.2:
4881 // If the converted initializer is a prvalue, its type T4 is adjusted
4882 // to type "cv1 T4" and the temporary materialization conversion is
4883 // applied.
4884 // Postpone address space conversions to after the temporary materialization
4885 // conversion to allow creating temporaries in the alloca address space.
4886 auto T1QualsIgnoreAS = T1Quals;
4887 auto T2QualsIgnoreAS = T2Quals;
4888 if (T1Quals.getAddressSpace() != T2Quals.getAddressSpace()) {
4889 T1QualsIgnoreAS.removeAddressSpace();
4890 T2QualsIgnoreAS.removeAddressSpace();
4891 }
4892 QualType cv1T4 = S.Context.getQualifiedType(cv2T2, T1QualsIgnoreAS);
4893 if (T1QualsIgnoreAS != T2QualsIgnoreAS)
4894 Sequence.AddQualificationConversionStep(cv1T4, ValueKind);
4895 Sequence.AddReferenceBindingStep(cv1T4, ValueKind == VK_RValue);
4896 ValueKind = isLValueRef ? VK_LValue : VK_XValue;
4897 // Add addr space conversion if required.
4898 if (T1Quals.getAddressSpace() != T2Quals.getAddressSpace()) {
4899 auto T4Quals = cv1T4.getQualifiers();
4900 T4Quals.addAddressSpace(T1Quals.getAddressSpace());
4901 QualType cv1T4WithAS = S.Context.getQualifiedType(T2, T4Quals);
4902 Sequence.AddQualificationConversionStep(cv1T4WithAS, ValueKind);
4903 cv1T4 = cv1T4WithAS;
4904 }
4905
4906 // In any case, the reference is bound to the resulting glvalue (or to
4907 // an appropriate base class subobject).
4908 if (RefConv & Sema::ReferenceConversions::DerivedToBase)
4909 Sequence.AddDerivedToBaseCastStep(cv1T1, ValueKind);
4910 else if (RefConv & Sema::ReferenceConversions::ObjC)
4911 Sequence.AddObjCObjectConversionStep(cv1T1);
4912 else if (RefConv & Sema::ReferenceConversions::Qualification) {
4913 if (!S.Context.hasSameType(cv1T4, cv1T1))
4914 Sequence.AddQualificationConversionStep(cv1T1, ValueKind);
4915 }
4916 return;
4917 }
4918
4919 // - has a class type (i.e., T2 is a class type), where T1 is not
4920 // reference-related to T2, and can be implicitly converted to an
4921 // xvalue, class prvalue, or function lvalue of type "cv3 T3",
4922 // where "cv1 T1" is reference-compatible with "cv3 T3",
4923 //
4924 // DR1287 removes the "implicitly" here.
4925 if (T2->isRecordType()) {
4926 if (RefRelationship == Sema::Ref_Incompatible) {
4927 ConvOvlResult = TryRefInitWithConversionFunction(
4928 S, Entity, Kind, Initializer, /*AllowRValues*/ true,
4929 /*IsLValueRef*/ isLValueRef, Sequence);
4930 if (ConvOvlResult)
4931 Sequence.SetOverloadFailure(
4932 InitializationSequence::FK_ReferenceInitOverloadFailed,
4933 ConvOvlResult);
4934
4935 return;
4936 }
4937
4938 if (RefRelationship == Sema::Ref_Compatible &&
4939 isRValueRef && InitCategory.isLValue()) {
4940 Sequence.SetFailed(
4941 InitializationSequence::FK_RValueReferenceBindingToLValue);
4942 return;
4943 }
4944
4945 Sequence.SetFailed(InitializationSequence::FK_ReferenceInitDropsQualifiers);
4946 return;
4947 }
4948
4949 // - Otherwise, a temporary of type "cv1 T1" is created and initialized
4950 // from the initializer expression using the rules for a non-reference
4951 // copy-initialization (8.5). The reference is then bound to the
4952 // temporary. [...]
4953
4954 // Ignore address space of reference type at this point and perform address
4955 // space conversion after the reference binding step.
4956 QualType cv1T1IgnoreAS =
4957 T1Quals.hasAddressSpace()
4958 ? S.Context.getQualifiedType(T1, T1Quals.withoutAddressSpace())
4959 : cv1T1;
4960
4961 InitializedEntity TempEntity =
4962 InitializedEntity::InitializeTemporary(cv1T1IgnoreAS);
4963
4964 // FIXME: Why do we use an implicit conversion here rather than trying
4965 // copy-initialization?
4966 ImplicitConversionSequence ICS
4967 = S.TryImplicitConversion(Initializer, TempEntity.getType(),
4968 /*SuppressUserConversions=*/false,
4969 Sema::AllowedExplicit::None,
4970 /*FIXME:InOverloadResolution=*/false,
4971 /*CStyle=*/Kind.isCStyleOrFunctionalCast(),
4972 /*AllowObjCWritebackConversion=*/false);
4973
4974 if (ICS.isBad()) {
4975 // FIXME: Use the conversion function set stored in ICS to turn
4976 // this into an overloading ambiguity diagnostic. However, we need
4977 // to keep that set as an OverloadCandidateSet rather than as some
4978 // other kind of set.
4979 if (ConvOvlResult && !Sequence.getFailedCandidateSet().empty())
4980 Sequence.SetOverloadFailure(
4981 InitializationSequence::FK_ReferenceInitOverloadFailed,
4982 ConvOvlResult);
4983 else if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy)
4984 Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
4985 else
4986 Sequence.SetFailed(InitializationSequence::FK_ReferenceInitFailed);
4987 return;
4988 } else {
4989 Sequence.AddConversionSequenceStep(ICS, TempEntity.getType());
4990 }
4991
4992 // [...] If T1 is reference-related to T2, cv1 must be the
4993 // same cv-qualification as, or greater cv-qualification
4994 // than, cv2; otherwise, the program is ill-formed.
4995 unsigned T1CVRQuals = T1Quals.getCVRQualifiers();
4996 unsigned T2CVRQuals = T2Quals.getCVRQualifiers();
4997 if ((RefRelationship == Sema::Ref_Related &&
4998 (T1CVRQuals | T2CVRQuals) != T1CVRQuals) ||
4999 !T1Quals.isAddressSpaceSupersetOf(T2Quals)) {
5000 Sequence.SetFailed(InitializationSequence::FK_ReferenceInitDropsQualifiers);
5001 return;
5002 }
5003
5004 // [...] If T1 is reference-related to T2 and the reference is an rvalue
5005 // reference, the initializer expression shall not be an lvalue.
5006 if (RefRelationship >= Sema::Ref_Related && !isLValueRef &&
5007 InitCategory.isLValue()) {
5008 Sequence.SetFailed(
5009 InitializationSequence::FK_RValueReferenceBindingToLValue);
5010 return;
5011 }
5012
5013 Sequence.AddReferenceBindingStep(cv1T1IgnoreAS, /*BindingTemporary=*/true);
5014
5015 if (T1Quals.hasAddressSpace()) {
5016 if (!Qualifiers::isAddressSpaceSupersetOf(T1Quals.getAddressSpace(),
5017 LangAS::Default)) {
5018 Sequence.SetFailed(
5019 InitializationSequence::FK_ReferenceAddrspaceMismatchTemporary);
5020 return;
5021 }
5022 Sequence.AddQualificationConversionStep(cv1T1, isLValueRef ? VK_LValue
5023 : VK_XValue);
5024 }
5025 }
5026
5027 /// Attempt character array initialization from a string literal
5028 /// (C++ [dcl.init.string], C99 6.7.8).
TryStringLiteralInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,Expr * Initializer,InitializationSequence & Sequence)5029 static void TryStringLiteralInitialization(Sema &S,
5030 const InitializedEntity &Entity,
5031 const InitializationKind &Kind,
5032 Expr *Initializer,
5033 InitializationSequence &Sequence) {
5034 Sequence.AddStringInitStep(Entity.getType());
5035 }
5036
5037 /// Attempt value initialization (C++ [dcl.init]p7).
TryValueInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,InitializationSequence & Sequence,InitListExpr * InitList)5038 static void TryValueInitialization(Sema &S,
5039 const InitializedEntity &Entity,
5040 const InitializationKind &Kind,
5041 InitializationSequence &Sequence,
5042 InitListExpr *InitList) {
5043 assert((!InitList || InitList->getNumInits() == 0) &&
5044 "Shouldn't use value-init for non-empty init lists");
5045
5046 // C++98 [dcl.init]p5, C++11 [dcl.init]p7:
5047 //
5048 // To value-initialize an object of type T means:
5049 QualType T = Entity.getType();
5050
5051 // -- if T is an array type, then each element is value-initialized;
5052 T = S.Context.getBaseElementType(T);
5053
5054 if (const RecordType *RT = T->getAs<RecordType>()) {
5055 if (CXXRecordDecl *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
5056 bool NeedZeroInitialization = true;
5057 // C++98:
5058 // -- if T is a class type (clause 9) with a user-declared constructor
5059 // (12.1), then the default constructor for T is called (and the
5060 // initialization is ill-formed if T has no accessible default
5061 // constructor);
5062 // C++11:
5063 // -- if T is a class type (clause 9) with either no default constructor
5064 // (12.1 [class.ctor]) or a default constructor that is user-provided
5065 // or deleted, then the object is default-initialized;
5066 //
5067 // Note that the C++11 rule is the same as the C++98 rule if there are no
5068 // defaulted or deleted constructors, so we just use it unconditionally.
5069 CXXConstructorDecl *CD = S.LookupDefaultConstructor(ClassDecl);
5070 if (!CD || !CD->getCanonicalDecl()->isDefaulted() || CD->isDeleted())
5071 NeedZeroInitialization = false;
5072
5073 // -- if T is a (possibly cv-qualified) non-union class type without a
5074 // user-provided or deleted default constructor, then the object is
5075 // zero-initialized and, if T has a non-trivial default constructor,
5076 // default-initialized;
5077 // The 'non-union' here was removed by DR1502. The 'non-trivial default
5078 // constructor' part was removed by DR1507.
5079 if (NeedZeroInitialization)
5080 Sequence.AddZeroInitializationStep(Entity.getType());
5081
5082 // C++03:
5083 // -- if T is a non-union class type without a user-declared constructor,
5084 // then every non-static data member and base class component of T is
5085 // value-initialized;
5086 // [...] A program that calls for [...] value-initialization of an
5087 // entity of reference type is ill-formed.
5088 //
5089 // C++11 doesn't need this handling, because value-initialization does not
5090 // occur recursively there, and the implicit default constructor is
5091 // defined as deleted in the problematic cases.
5092 if (!S.getLangOpts().CPlusPlus11 &&
5093 ClassDecl->hasUninitializedReferenceMember()) {
5094 Sequence.SetFailed(InitializationSequence::FK_TooManyInitsForReference);
5095 return;
5096 }
5097
5098 // If this is list-value-initialization, pass the empty init list on when
5099 // building the constructor call. This affects the semantics of a few
5100 // things (such as whether an explicit default constructor can be called).
5101 Expr *InitListAsExpr = InitList;
5102 MultiExprArg Args(&InitListAsExpr, InitList ? 1 : 0);
5103 bool InitListSyntax = InitList;
5104
5105 // FIXME: Instead of creating a CXXConstructExpr of array type here,
5106 // wrap a class-typed CXXConstructExpr in an ArrayInitLoopExpr.
5107 return TryConstructorInitialization(
5108 S, Entity, Kind, Args, T, Entity.getType(), Sequence, InitListSyntax);
5109 }
5110 }
5111
5112 Sequence.AddZeroInitializationStep(Entity.getType());
5113 }
5114
5115 /// Attempt default initialization (C++ [dcl.init]p6).
TryDefaultInitialization(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,InitializationSequence & Sequence)5116 static void TryDefaultInitialization(Sema &S,
5117 const InitializedEntity &Entity,
5118 const InitializationKind &Kind,
5119 InitializationSequence &Sequence) {
5120 assert(Kind.getKind() == InitializationKind::IK_Default);
5121
5122 // C++ [dcl.init]p6:
5123 // To default-initialize an object of type T means:
5124 // - if T is an array type, each element is default-initialized;
5125 QualType DestType = S.Context.getBaseElementType(Entity.getType());
5126
5127 // - if T is a (possibly cv-qualified) class type (Clause 9), the default
5128 // constructor for T is called (and the initialization is ill-formed if
5129 // T has no accessible default constructor);
5130 if (DestType->isRecordType() && S.getLangOpts().CPlusPlus) {
5131 TryConstructorInitialization(S, Entity, Kind, None, DestType,
5132 Entity.getType(), Sequence);
5133 return;
5134 }
5135
5136 // - otherwise, no initialization is performed.
5137
5138 // If a program calls for the default initialization of an object of
5139 // a const-qualified type T, T shall be a class type with a user-provided
5140 // default constructor.
5141 if (DestType.isConstQualified() && S.getLangOpts().CPlusPlus) {
5142 if (!maybeRecoverWithZeroInitialization(S, Sequence, Entity))
5143 Sequence.SetFailed(InitializationSequence::FK_DefaultInitOfConst);
5144 return;
5145 }
5146
5147 // If the destination type has a lifetime property, zero-initialize it.
5148 if (DestType.getQualifiers().hasObjCLifetime()) {
5149 Sequence.AddZeroInitializationStep(Entity.getType());
5150 return;
5151 }
5152 }
5153
5154 /// Attempt a user-defined conversion between two types (C++ [dcl.init]),
5155 /// which enumerates all conversion functions and performs overload resolution
5156 /// to select the best.
TryUserDefinedConversion(Sema & S,QualType DestType,const InitializationKind & Kind,Expr * Initializer,InitializationSequence & Sequence,bool TopLevelOfInitList)5157 static void TryUserDefinedConversion(Sema &S,
5158 QualType DestType,
5159 const InitializationKind &Kind,
5160 Expr *Initializer,
5161 InitializationSequence &Sequence,
5162 bool TopLevelOfInitList) {
5163 assert(!DestType->isReferenceType() && "References are handled elsewhere");
5164 QualType SourceType = Initializer->getType();
5165 assert((DestType->isRecordType() || SourceType->isRecordType()) &&
5166 "Must have a class type to perform a user-defined conversion");
5167
5168 // Build the candidate set directly in the initialization sequence
5169 // structure, so that it will persist if we fail.
5170 OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
5171 CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
5172 CandidateSet.setDestAS(DestType.getQualifiers().getAddressSpace());
5173
5174 // Determine whether we are allowed to call explicit constructors or
5175 // explicit conversion operators.
5176 bool AllowExplicit = Kind.AllowExplicit();
5177
5178 if (const RecordType *DestRecordType = DestType->getAs<RecordType>()) {
5179 // The type we're converting to is a class type. Enumerate its constructors
5180 // to see if there is a suitable conversion.
5181 CXXRecordDecl *DestRecordDecl
5182 = cast<CXXRecordDecl>(DestRecordType->getDecl());
5183
5184 // Try to complete the type we're converting to.
5185 if (S.isCompleteType(Kind.getLocation(), DestType)) {
5186 for (NamedDecl *D : S.LookupConstructors(DestRecordDecl)) {
5187 auto Info = getConstructorInfo(D);
5188 if (!Info.Constructor)
5189 continue;
5190
5191 if (!Info.Constructor->isInvalidDecl() &&
5192 Info.Constructor->isConvertingConstructor(/*AllowExplicit*/true)) {
5193 if (Info.ConstructorTmpl)
5194 S.AddTemplateOverloadCandidate(
5195 Info.ConstructorTmpl, Info.FoundDecl,
5196 /*ExplicitArgs*/ nullptr, Initializer, CandidateSet,
5197 /*SuppressUserConversions=*/true,
5198 /*PartialOverloading*/ false, AllowExplicit);
5199 else
5200 S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl,
5201 Initializer, CandidateSet,
5202 /*SuppressUserConversions=*/true,
5203 /*PartialOverloading*/ false, AllowExplicit);
5204 }
5205 }
5206 }
5207 }
5208
5209 SourceLocation DeclLoc = Initializer->getBeginLoc();
5210
5211 if (const RecordType *SourceRecordType = SourceType->getAs<RecordType>()) {
5212 // The type we're converting from is a class type, enumerate its conversion
5213 // functions.
5214
5215 // We can only enumerate the conversion functions for a complete type; if
5216 // the type isn't complete, simply skip this step.
5217 if (S.isCompleteType(DeclLoc, SourceType)) {
5218 CXXRecordDecl *SourceRecordDecl
5219 = cast<CXXRecordDecl>(SourceRecordType->getDecl());
5220
5221 const auto &Conversions =
5222 SourceRecordDecl->getVisibleConversionFunctions();
5223 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
5224 NamedDecl *D = *I;
5225 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
5226 if (isa<UsingShadowDecl>(D))
5227 D = cast<UsingShadowDecl>(D)->getTargetDecl();
5228
5229 FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
5230 CXXConversionDecl *Conv;
5231 if (ConvTemplate)
5232 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
5233 else
5234 Conv = cast<CXXConversionDecl>(D);
5235
5236 if (ConvTemplate)
5237 S.AddTemplateConversionCandidate(
5238 ConvTemplate, I.getPair(), ActingDC, Initializer, DestType,
5239 CandidateSet, AllowExplicit, AllowExplicit);
5240 else
5241 S.AddConversionCandidate(Conv, I.getPair(), ActingDC, Initializer,
5242 DestType, CandidateSet, AllowExplicit,
5243 AllowExplicit);
5244 }
5245 }
5246 }
5247
5248 // Perform overload resolution. If it fails, return the failed result.
5249 OverloadCandidateSet::iterator Best;
5250 if (OverloadingResult Result
5251 = CandidateSet.BestViableFunction(S, DeclLoc, Best)) {
5252 Sequence.SetOverloadFailure(
5253 InitializationSequence::FK_UserConversionOverloadFailed,
5254 Result);
5255 return;
5256 }
5257
5258 FunctionDecl *Function = Best->Function;
5259 Function->setReferenced();
5260 bool HadMultipleCandidates = (CandidateSet.size() > 1);
5261
5262 if (isa<CXXConstructorDecl>(Function)) {
5263 // Add the user-defined conversion step. Any cv-qualification conversion is
5264 // subsumed by the initialization. Per DR5, the created temporary is of the
5265 // cv-unqualified type of the destination.
5266 Sequence.AddUserConversionStep(Function, Best->FoundDecl,
5267 DestType.getUnqualifiedType(),
5268 HadMultipleCandidates);
5269
5270 // C++14 and before:
5271 // - if the function is a constructor, the call initializes a temporary
5272 // of the cv-unqualified version of the destination type. The [...]
5273 // temporary [...] is then used to direct-initialize, according to the
5274 // rules above, the object that is the destination of the
5275 // copy-initialization.
5276 // Note that this just performs a simple object copy from the temporary.
5277 //
5278 // C++17:
5279 // - if the function is a constructor, the call is a prvalue of the
5280 // cv-unqualified version of the destination type whose return object
5281 // is initialized by the constructor. The call is used to
5282 // direct-initialize, according to the rules above, the object that
5283 // is the destination of the copy-initialization.
5284 // Therefore we need to do nothing further.
5285 //
5286 // FIXME: Mark this copy as extraneous.
5287 if (!S.getLangOpts().CPlusPlus17)
5288 Sequence.AddFinalCopy(DestType);
5289 else if (DestType.hasQualifiers())
5290 Sequence.AddQualificationConversionStep(DestType, VK_RValue);
5291 return;
5292 }
5293
5294 // Add the user-defined conversion step that calls the conversion function.
5295 QualType ConvType = Function->getCallResultType();
5296 Sequence.AddUserConversionStep(Function, Best->FoundDecl, ConvType,
5297 HadMultipleCandidates);
5298
5299 if (ConvType->getAs<RecordType>()) {
5300 // The call is used to direct-initialize [...] the object that is the
5301 // destination of the copy-initialization.
5302 //
5303 // In C++17, this does not call a constructor if we enter /17.6.1:
5304 // - If the initializer expression is a prvalue and the cv-unqualified
5305 // version of the source type is the same as the class of the
5306 // destination [... do not make an extra copy]
5307 //
5308 // FIXME: Mark this copy as extraneous.
5309 if (!S.getLangOpts().CPlusPlus17 ||
5310 Function->getReturnType()->isReferenceType() ||
5311 !S.Context.hasSameUnqualifiedType(ConvType, DestType))
5312 Sequence.AddFinalCopy(DestType);
5313 else if (!S.Context.hasSameType(ConvType, DestType))
5314 Sequence.AddQualificationConversionStep(DestType, VK_RValue);
5315 return;
5316 }
5317
5318 // If the conversion following the call to the conversion function
5319 // is interesting, add it as a separate step.
5320 if (Best->FinalConversion.First || Best->FinalConversion.Second ||
5321 Best->FinalConversion.Third) {
5322 ImplicitConversionSequence ICS;
5323 ICS.setStandard();
5324 ICS.Standard = Best->FinalConversion;
5325 Sequence.AddConversionSequenceStep(ICS, DestType, TopLevelOfInitList);
5326 }
5327 }
5328
5329 /// An egregious hack for compatibility with libstdc++-4.2: in <tr1/hashtable>,
5330 /// a function with a pointer return type contains a 'return false;' statement.
5331 /// In C++11, 'false' is not a null pointer, so this breaks the build of any
5332 /// code using that header.
5333 ///
5334 /// Work around this by treating 'return false;' as zero-initializing the result
5335 /// if it's used in a pointer-returning function in a system header.
isLibstdcxxPointerReturnFalseHack(Sema & S,const InitializedEntity & Entity,const Expr * Init)5336 static bool isLibstdcxxPointerReturnFalseHack(Sema &S,
5337 const InitializedEntity &Entity,
5338 const Expr *Init) {
5339 return S.getLangOpts().CPlusPlus11 &&
5340 Entity.getKind() == InitializedEntity::EK_Result &&
5341 Entity.getType()->isPointerType() &&
5342 isa<CXXBoolLiteralExpr>(Init) &&
5343 !cast<CXXBoolLiteralExpr>(Init)->getValue() &&
5344 S.getSourceManager().isInSystemHeader(Init->getExprLoc());
5345 }
5346
5347 /// The non-zero enum values here are indexes into diagnostic alternatives.
5348 enum InvalidICRKind { IIK_okay, IIK_nonlocal, IIK_nonscalar };
5349
5350 /// Determines whether this expression is an acceptable ICR source.
isInvalidICRSource(ASTContext & C,Expr * e,bool isAddressOf,bool & isWeakAccess)5351 static InvalidICRKind isInvalidICRSource(ASTContext &C, Expr *e,
5352 bool isAddressOf, bool &isWeakAccess) {
5353 // Skip parens.
5354 e = e->IgnoreParens();
5355
5356 // Skip address-of nodes.
5357 if (UnaryOperator *op = dyn_cast<UnaryOperator>(e)) {
5358 if (op->getOpcode() == UO_AddrOf)
5359 return isInvalidICRSource(C, op->getSubExpr(), /*addressof*/ true,
5360 isWeakAccess);
5361
5362 // Skip certain casts.
5363 } else if (CastExpr *ce = dyn_cast<CastExpr>(e)) {
5364 switch (ce->getCastKind()) {
5365 case CK_Dependent:
5366 case CK_BitCast:
5367 case CK_LValueBitCast:
5368 case CK_NoOp:
5369 return isInvalidICRSource(C, ce->getSubExpr(), isAddressOf, isWeakAccess);
5370
5371 case CK_ArrayToPointerDecay:
5372 return IIK_nonscalar;
5373
5374 case CK_NullToPointer:
5375 return IIK_okay;
5376
5377 default:
5378 break;
5379 }
5380
5381 // If we have a declaration reference, it had better be a local variable.
5382 } else if (isa<DeclRefExpr>(e)) {
5383 // set isWeakAccess to true, to mean that there will be an implicit
5384 // load which requires a cleanup.
5385 if (e->getType().getObjCLifetime() == Qualifiers::OCL_Weak)
5386 isWeakAccess = true;
5387
5388 if (!isAddressOf) return IIK_nonlocal;
5389
5390 VarDecl *var = dyn_cast<VarDecl>(cast<DeclRefExpr>(e)->getDecl());
5391 if (!var) return IIK_nonlocal;
5392
5393 return (var->hasLocalStorage() ? IIK_okay : IIK_nonlocal);
5394
5395 // If we have a conditional operator, check both sides.
5396 } else if (ConditionalOperator *cond = dyn_cast<ConditionalOperator>(e)) {
5397 if (InvalidICRKind iik = isInvalidICRSource(C, cond->getLHS(), isAddressOf,
5398 isWeakAccess))
5399 return iik;
5400
5401 return isInvalidICRSource(C, cond->getRHS(), isAddressOf, isWeakAccess);
5402
5403 // These are never scalar.
5404 } else if (isa<ArraySubscriptExpr>(e)) {
5405 return IIK_nonscalar;
5406
5407 // Otherwise, it needs to be a null pointer constant.
5408 } else {
5409 return (e->isNullPointerConstant(C, Expr::NPC_ValueDependentIsNull)
5410 ? IIK_okay : IIK_nonlocal);
5411 }
5412
5413 return IIK_nonlocal;
5414 }
5415
5416 /// Check whether the given expression is a valid operand for an
5417 /// indirect copy/restore.
checkIndirectCopyRestoreSource(Sema & S,Expr * src)5418 static void checkIndirectCopyRestoreSource(Sema &S, Expr *src) {
5419 assert(src->isRValue());
5420 bool isWeakAccess = false;
5421 InvalidICRKind iik = isInvalidICRSource(S.Context, src, false, isWeakAccess);
5422 // If isWeakAccess to true, there will be an implicit
5423 // load which requires a cleanup.
5424 if (S.getLangOpts().ObjCAutoRefCount && isWeakAccess)
5425 S.Cleanup.setExprNeedsCleanups(true);
5426
5427 if (iik == IIK_okay) return;
5428
5429 S.Diag(src->getExprLoc(), diag::err_arc_nonlocal_writeback)
5430 << ((unsigned) iik - 1) // shift index into diagnostic explanations
5431 << src->getSourceRange();
5432 }
5433
5434 /// Determine whether we have compatible array types for the
5435 /// purposes of GNU by-copy array initialization.
hasCompatibleArrayTypes(ASTContext & Context,const ArrayType * Dest,const ArrayType * Source)5436 static bool hasCompatibleArrayTypes(ASTContext &Context, const ArrayType *Dest,
5437 const ArrayType *Source) {
5438 // If the source and destination array types are equivalent, we're
5439 // done.
5440 if (Context.hasSameType(QualType(Dest, 0), QualType(Source, 0)))
5441 return true;
5442
5443 // Make sure that the element types are the same.
5444 if (!Context.hasSameType(Dest->getElementType(), Source->getElementType()))
5445 return false;
5446
5447 // The only mismatch we allow is when the destination is an
5448 // incomplete array type and the source is a constant array type.
5449 return Source->isConstantArrayType() && Dest->isIncompleteArrayType();
5450 }
5451
tryObjCWritebackConversion(Sema & S,InitializationSequence & Sequence,const InitializedEntity & Entity,Expr * Initializer)5452 static bool tryObjCWritebackConversion(Sema &S,
5453 InitializationSequence &Sequence,
5454 const InitializedEntity &Entity,
5455 Expr *Initializer) {
5456 bool ArrayDecay = false;
5457 QualType ArgType = Initializer->getType();
5458 QualType ArgPointee;
5459 if (const ArrayType *ArgArrayType = S.Context.getAsArrayType(ArgType)) {
5460 ArrayDecay = true;
5461 ArgPointee = ArgArrayType->getElementType();
5462 ArgType = S.Context.getPointerType(ArgPointee);
5463 }
5464
5465 // Handle write-back conversion.
5466 QualType ConvertedArgType;
5467 if (!S.isObjCWritebackConversion(ArgType, Entity.getType(),
5468 ConvertedArgType))
5469 return false;
5470
5471 // We should copy unless we're passing to an argument explicitly
5472 // marked 'out'.
5473 bool ShouldCopy = true;
5474 if (ParmVarDecl *param = cast_or_null<ParmVarDecl>(Entity.getDecl()))
5475 ShouldCopy = (param->getObjCDeclQualifier() != ParmVarDecl::OBJC_TQ_Out);
5476
5477 // Do we need an lvalue conversion?
5478 if (ArrayDecay || Initializer->isGLValue()) {
5479 ImplicitConversionSequence ICS;
5480 ICS.setStandard();
5481 ICS.Standard.setAsIdentityConversion();
5482
5483 QualType ResultType;
5484 if (ArrayDecay) {
5485 ICS.Standard.First = ICK_Array_To_Pointer;
5486 ResultType = S.Context.getPointerType(ArgPointee);
5487 } else {
5488 ICS.Standard.First = ICK_Lvalue_To_Rvalue;
5489 ResultType = Initializer->getType().getNonLValueExprType(S.Context);
5490 }
5491
5492 Sequence.AddConversionSequenceStep(ICS, ResultType);
5493 }
5494
5495 Sequence.AddPassByIndirectCopyRestoreStep(Entity.getType(), ShouldCopy);
5496 return true;
5497 }
5498
TryOCLSamplerInitialization(Sema & S,InitializationSequence & Sequence,QualType DestType,Expr * Initializer)5499 static bool TryOCLSamplerInitialization(Sema &S,
5500 InitializationSequence &Sequence,
5501 QualType DestType,
5502 Expr *Initializer) {
5503 if (!S.getLangOpts().OpenCL || !DestType->isSamplerT() ||
5504 (!Initializer->isIntegerConstantExpr(S.Context) &&
5505 !Initializer->getType()->isSamplerT()))
5506 return false;
5507
5508 Sequence.AddOCLSamplerInitStep(DestType);
5509 return true;
5510 }
5511
IsZeroInitializer(Expr * Initializer,Sema & S)5512 static bool IsZeroInitializer(Expr *Initializer, Sema &S) {
5513 return Initializer->isIntegerConstantExpr(S.getASTContext()) &&
5514 (Initializer->EvaluateKnownConstInt(S.getASTContext()) == 0);
5515 }
5516
TryOCLZeroOpaqueTypeInitialization(Sema & S,InitializationSequence & Sequence,QualType DestType,Expr * Initializer)5517 static bool TryOCLZeroOpaqueTypeInitialization(Sema &S,
5518 InitializationSequence &Sequence,
5519 QualType DestType,
5520 Expr *Initializer) {
5521 if (!S.getLangOpts().OpenCL)
5522 return false;
5523
5524 //
5525 // OpenCL 1.2 spec, s6.12.10
5526 //
5527 // The event argument can also be used to associate the
5528 // async_work_group_copy with a previous async copy allowing
5529 // an event to be shared by multiple async copies; otherwise
5530 // event should be zero.
5531 //
5532 if (DestType->isEventT() || DestType->isQueueT()) {
5533 if (!IsZeroInitializer(Initializer, S))
5534 return false;
5535
5536 Sequence.AddOCLZeroOpaqueTypeStep(DestType);
5537 return true;
5538 }
5539
5540 // We should allow zero initialization for all types defined in the
5541 // cl_intel_device_side_avc_motion_estimation extension, except
5542 // intel_sub_group_avc_mce_payload_t and intel_sub_group_avc_mce_result_t.
5543 if (S.getOpenCLOptions().isEnabled(
5544 "cl_intel_device_side_avc_motion_estimation") &&
5545 DestType->isOCLIntelSubgroupAVCType()) {
5546 if (DestType->isOCLIntelSubgroupAVCMcePayloadType() ||
5547 DestType->isOCLIntelSubgroupAVCMceResultType())
5548 return false;
5549 if (!IsZeroInitializer(Initializer, S))
5550 return false;
5551
5552 Sequence.AddOCLZeroOpaqueTypeStep(DestType);
5553 return true;
5554 }
5555
5556 return false;
5557 }
5558
InitializationSequence(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Args,bool TopLevelOfInitList,bool TreatUnavailableAsInvalid)5559 InitializationSequence::InitializationSequence(Sema &S,
5560 const InitializedEntity &Entity,
5561 const InitializationKind &Kind,
5562 MultiExprArg Args,
5563 bool TopLevelOfInitList,
5564 bool TreatUnavailableAsInvalid)
5565 : FailedCandidateSet(Kind.getLocation(), OverloadCandidateSet::CSK_Normal) {
5566 InitializeFrom(S, Entity, Kind, Args, TopLevelOfInitList,
5567 TreatUnavailableAsInvalid);
5568 }
5569
5570 /// Tries to get a FunctionDecl out of `E`. If it succeeds and we can take the
5571 /// address of that function, this returns true. Otherwise, it returns false.
isExprAnUnaddressableFunction(Sema & S,const Expr * E)5572 static bool isExprAnUnaddressableFunction(Sema &S, const Expr *E) {
5573 auto *DRE = dyn_cast<DeclRefExpr>(E);
5574 if (!DRE || !isa<FunctionDecl>(DRE->getDecl()))
5575 return false;
5576
5577 return !S.checkAddressOfFunctionIsAvailable(
5578 cast<FunctionDecl>(DRE->getDecl()));
5579 }
5580
5581 /// Determine whether we can perform an elementwise array copy for this kind
5582 /// of entity.
canPerformArrayCopy(const InitializedEntity & Entity)5583 static bool canPerformArrayCopy(const InitializedEntity &Entity) {
5584 switch (Entity.getKind()) {
5585 case InitializedEntity::EK_LambdaCapture:
5586 // C++ [expr.prim.lambda]p24:
5587 // For array members, the array elements are direct-initialized in
5588 // increasing subscript order.
5589 return true;
5590
5591 case InitializedEntity::EK_Variable:
5592 // C++ [dcl.decomp]p1:
5593 // [...] each element is copy-initialized or direct-initialized from the
5594 // corresponding element of the assignment-expression [...]
5595 return isa<DecompositionDecl>(Entity.getDecl());
5596
5597 case InitializedEntity::EK_Member:
5598 // C++ [class.copy.ctor]p14:
5599 // - if the member is an array, each element is direct-initialized with
5600 // the corresponding subobject of x
5601 return Entity.isImplicitMemberInitializer();
5602
5603 case InitializedEntity::EK_ArrayElement:
5604 // All the above cases are intended to apply recursively, even though none
5605 // of them actually say that.
5606 if (auto *E = Entity.getParent())
5607 return canPerformArrayCopy(*E);
5608 break;
5609
5610 default:
5611 break;
5612 }
5613
5614 return false;
5615 }
5616
InitializeFrom(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Args,bool TopLevelOfInitList,bool TreatUnavailableAsInvalid)5617 void InitializationSequence::InitializeFrom(Sema &S,
5618 const InitializedEntity &Entity,
5619 const InitializationKind &Kind,
5620 MultiExprArg Args,
5621 bool TopLevelOfInitList,
5622 bool TreatUnavailableAsInvalid) {
5623 ASTContext &Context = S.Context;
5624
5625 // Eliminate non-overload placeholder types in the arguments. We
5626 // need to do this before checking whether types are dependent
5627 // because lowering a pseudo-object expression might well give us
5628 // something of dependent type.
5629 for (unsigned I = 0, E = Args.size(); I != E; ++I)
5630 if (Args[I]->getType()->isNonOverloadPlaceholderType()) {
5631 // FIXME: should we be doing this here?
5632 ExprResult result = S.CheckPlaceholderExpr(Args[I]);
5633 if (result.isInvalid()) {
5634 SetFailed(FK_PlaceholderType);
5635 return;
5636 }
5637 Args[I] = result.get();
5638 }
5639
5640 // C++0x [dcl.init]p16:
5641 // The semantics of initializers are as follows. The destination type is
5642 // the type of the object or reference being initialized and the source
5643 // type is the type of the initializer expression. The source type is not
5644 // defined when the initializer is a braced-init-list or when it is a
5645 // parenthesized list of expressions.
5646 QualType DestType = Entity.getType();
5647
5648 if (DestType->isDependentType() ||
5649 Expr::hasAnyTypeDependentArguments(Args)) {
5650 SequenceKind = DependentSequence;
5651 return;
5652 }
5653
5654 // Almost everything is a normal sequence.
5655 setSequenceKind(NormalSequence);
5656
5657 QualType SourceType;
5658 Expr *Initializer = nullptr;
5659 if (Args.size() == 1) {
5660 Initializer = Args[0];
5661 if (S.getLangOpts().ObjC) {
5662 if (S.CheckObjCBridgeRelatedConversions(Initializer->getBeginLoc(),
5663 DestType, Initializer->getType(),
5664 Initializer) ||
5665 S.CheckConversionToObjCLiteral(DestType, Initializer))
5666 Args[0] = Initializer;
5667 }
5668 if (!isa<InitListExpr>(Initializer))
5669 SourceType = Initializer->getType();
5670 }
5671
5672 // - If the initializer is a (non-parenthesized) braced-init-list, the
5673 // object is list-initialized (8.5.4).
5674 if (Kind.getKind() != InitializationKind::IK_Direct) {
5675 if (InitListExpr *InitList = dyn_cast_or_null<InitListExpr>(Initializer)) {
5676 TryListInitialization(S, Entity, Kind, InitList, *this,
5677 TreatUnavailableAsInvalid);
5678 return;
5679 }
5680 }
5681
5682 // - If the destination type is a reference type, see 8.5.3.
5683 if (DestType->isReferenceType()) {
5684 // C++0x [dcl.init.ref]p1:
5685 // A variable declared to be a T& or T&&, that is, "reference to type T"
5686 // (8.3.2), shall be initialized by an object, or function, of type T or
5687 // by an object that can be converted into a T.
5688 // (Therefore, multiple arguments are not permitted.)
5689 if (Args.size() != 1)
5690 SetFailed(FK_TooManyInitsForReference);
5691 // C++17 [dcl.init.ref]p5:
5692 // A reference [...] is initialized by an expression [...] as follows:
5693 // If the initializer is not an expression, presumably we should reject,
5694 // but the standard fails to actually say so.
5695 else if (isa<InitListExpr>(Args[0]))
5696 SetFailed(FK_ParenthesizedListInitForReference);
5697 else
5698 TryReferenceInitialization(S, Entity, Kind, Args[0], *this);
5699 return;
5700 }
5701
5702 // - If the initializer is (), the object is value-initialized.
5703 if (Kind.getKind() == InitializationKind::IK_Value ||
5704 (Kind.getKind() == InitializationKind::IK_Direct && Args.empty())) {
5705 TryValueInitialization(S, Entity, Kind, *this);
5706 return;
5707 }
5708
5709 // Handle default initialization.
5710 if (Kind.getKind() == InitializationKind::IK_Default) {
5711 TryDefaultInitialization(S, Entity, Kind, *this);
5712 return;
5713 }
5714
5715 // - If the destination type is an array of characters, an array of
5716 // char16_t, an array of char32_t, or an array of wchar_t, and the
5717 // initializer is a string literal, see 8.5.2.
5718 // - Otherwise, if the destination type is an array, the program is
5719 // ill-formed.
5720 if (const ArrayType *DestAT = Context.getAsArrayType(DestType)) {
5721 if (Initializer && isa<VariableArrayType>(DestAT)) {
5722 SetFailed(FK_VariableLengthArrayHasInitializer);
5723 return;
5724 }
5725
5726 if (Initializer) {
5727 switch (IsStringInit(Initializer, DestAT, Context)) {
5728 case SIF_None:
5729 TryStringLiteralInitialization(S, Entity, Kind, Initializer, *this);
5730 return;
5731 case SIF_NarrowStringIntoWideChar:
5732 SetFailed(FK_NarrowStringIntoWideCharArray);
5733 return;
5734 case SIF_WideStringIntoChar:
5735 SetFailed(FK_WideStringIntoCharArray);
5736 return;
5737 case SIF_IncompatWideStringIntoWideChar:
5738 SetFailed(FK_IncompatWideStringIntoWideChar);
5739 return;
5740 case SIF_PlainStringIntoUTF8Char:
5741 SetFailed(FK_PlainStringIntoUTF8Char);
5742 return;
5743 case SIF_UTF8StringIntoPlainChar:
5744 SetFailed(FK_UTF8StringIntoPlainChar);
5745 return;
5746 case SIF_Other:
5747 break;
5748 }
5749 }
5750
5751 // Some kinds of initialization permit an array to be initialized from
5752 // another array of the same type, and perform elementwise initialization.
5753 if (Initializer && isa<ConstantArrayType>(DestAT) &&
5754 S.Context.hasSameUnqualifiedType(Initializer->getType(),
5755 Entity.getType()) &&
5756 canPerformArrayCopy(Entity)) {
5757 // If source is a prvalue, use it directly.
5758 if (Initializer->getValueKind() == VK_RValue) {
5759 AddArrayInitStep(DestType, /*IsGNUExtension*/false);
5760 return;
5761 }
5762
5763 // Emit element-at-a-time copy loop.
5764 InitializedEntity Element =
5765 InitializedEntity::InitializeElement(S.Context, 0, Entity);
5766 QualType InitEltT =
5767 Context.getAsArrayType(Initializer->getType())->getElementType();
5768 OpaqueValueExpr OVE(Initializer->getExprLoc(), InitEltT,
5769 Initializer->getValueKind(),
5770 Initializer->getObjectKind());
5771 Expr *OVEAsExpr = &OVE;
5772 InitializeFrom(S, Element, Kind, OVEAsExpr, TopLevelOfInitList,
5773 TreatUnavailableAsInvalid);
5774 if (!Failed())
5775 AddArrayInitLoopStep(Entity.getType(), InitEltT);
5776 return;
5777 }
5778
5779 // Note: as an GNU C extension, we allow initialization of an
5780 // array from a compound literal that creates an array of the same
5781 // type, so long as the initializer has no side effects.
5782 if (!S.getLangOpts().CPlusPlus && Initializer &&
5783 isa<CompoundLiteralExpr>(Initializer->IgnoreParens()) &&
5784 Initializer->getType()->isArrayType()) {
5785 const ArrayType *SourceAT
5786 = Context.getAsArrayType(Initializer->getType());
5787 if (!hasCompatibleArrayTypes(S.Context, DestAT, SourceAT))
5788 SetFailed(FK_ArrayTypeMismatch);
5789 else if (Initializer->HasSideEffects(S.Context))
5790 SetFailed(FK_NonConstantArrayInit);
5791 else {
5792 AddArrayInitStep(DestType, /*IsGNUExtension*/true);
5793 }
5794 }
5795 // Note: as a GNU C++ extension, we allow list-initialization of a
5796 // class member of array type from a parenthesized initializer list.
5797 else if (S.getLangOpts().CPlusPlus &&
5798 Entity.getKind() == InitializedEntity::EK_Member &&
5799 Initializer && isa<InitListExpr>(Initializer)) {
5800 TryListInitialization(S, Entity, Kind, cast<InitListExpr>(Initializer),
5801 *this, TreatUnavailableAsInvalid);
5802 AddParenthesizedArrayInitStep(DestType);
5803 } else if (DestAT->getElementType()->isCharType())
5804 SetFailed(FK_ArrayNeedsInitListOrStringLiteral);
5805 else if (IsWideCharCompatible(DestAT->getElementType(), Context))
5806 SetFailed(FK_ArrayNeedsInitListOrWideStringLiteral);
5807 else
5808 SetFailed(FK_ArrayNeedsInitList);
5809
5810 return;
5811 }
5812
5813 // Determine whether we should consider writeback conversions for
5814 // Objective-C ARC.
5815 bool allowObjCWritebackConversion = S.getLangOpts().ObjCAutoRefCount &&
5816 Entity.isParameterKind();
5817
5818 if (TryOCLSamplerInitialization(S, *this, DestType, Initializer))
5819 return;
5820
5821 // We're at the end of the line for C: it's either a write-back conversion
5822 // or it's a C assignment. There's no need to check anything else.
5823 if (!S.getLangOpts().CPlusPlus) {
5824 // If allowed, check whether this is an Objective-C writeback conversion.
5825 if (allowObjCWritebackConversion &&
5826 tryObjCWritebackConversion(S, *this, Entity, Initializer)) {
5827 return;
5828 }
5829
5830 if (TryOCLZeroOpaqueTypeInitialization(S, *this, DestType, Initializer))
5831 return;
5832
5833 // Handle initialization in C
5834 AddCAssignmentStep(DestType);
5835 MaybeProduceObjCObject(S, *this, Entity);
5836 return;
5837 }
5838
5839 assert(S.getLangOpts().CPlusPlus);
5840
5841 // - If the destination type is a (possibly cv-qualified) class type:
5842 if (DestType->isRecordType()) {
5843 // - If the initialization is direct-initialization, or if it is
5844 // copy-initialization where the cv-unqualified version of the
5845 // source type is the same class as, or a derived class of, the
5846 // class of the destination, constructors are considered. [...]
5847 if (Kind.getKind() == InitializationKind::IK_Direct ||
5848 (Kind.getKind() == InitializationKind::IK_Copy &&
5849 (Context.hasSameUnqualifiedType(SourceType, DestType) ||
5850 S.IsDerivedFrom(Initializer->getBeginLoc(), SourceType, DestType))))
5851 TryConstructorInitialization(S, Entity, Kind, Args,
5852 DestType, DestType, *this);
5853 // - Otherwise (i.e., for the remaining copy-initialization cases),
5854 // user-defined conversion sequences that can convert from the source
5855 // type to the destination type or (when a conversion function is
5856 // used) to a derived class thereof are enumerated as described in
5857 // 13.3.1.4, and the best one is chosen through overload resolution
5858 // (13.3).
5859 else
5860 TryUserDefinedConversion(S, DestType, Kind, Initializer, *this,
5861 TopLevelOfInitList);
5862 return;
5863 }
5864
5865 assert(Args.size() >= 1 && "Zero-argument case handled above");
5866
5867 // The remaining cases all need a source type.
5868 if (Args.size() > 1) {
5869 SetFailed(FK_TooManyInitsForScalar);
5870 return;
5871 } else if (isa<InitListExpr>(Args[0])) {
5872 SetFailed(FK_ParenthesizedListInitForScalar);
5873 return;
5874 }
5875
5876 // - Otherwise, if the source type is a (possibly cv-qualified) class
5877 // type, conversion functions are considered.
5878 if (!SourceType.isNull() && SourceType->isRecordType()) {
5879 // For a conversion to _Atomic(T) from either T or a class type derived
5880 // from T, initialize the T object then convert to _Atomic type.
5881 bool NeedAtomicConversion = false;
5882 if (const AtomicType *Atomic = DestType->getAs<AtomicType>()) {
5883 if (Context.hasSameUnqualifiedType(SourceType, Atomic->getValueType()) ||
5884 S.IsDerivedFrom(Initializer->getBeginLoc(), SourceType,
5885 Atomic->getValueType())) {
5886 DestType = Atomic->getValueType();
5887 NeedAtomicConversion = true;
5888 }
5889 }
5890
5891 TryUserDefinedConversion(S, DestType, Kind, Initializer, *this,
5892 TopLevelOfInitList);
5893 MaybeProduceObjCObject(S, *this, Entity);
5894 if (!Failed() && NeedAtomicConversion)
5895 AddAtomicConversionStep(Entity.getType());
5896 return;
5897 }
5898
5899 // - Otherwise, if the initialization is direct-initialization, the source
5900 // type is std::nullptr_t, and the destination type is bool, the initial
5901 // value of the object being initialized is false.
5902 if (!SourceType.isNull() && SourceType->isNullPtrType() &&
5903 DestType->isBooleanType() &&
5904 Kind.getKind() == InitializationKind::IK_Direct) {
5905 AddConversionSequenceStep(
5906 ImplicitConversionSequence::getNullptrToBool(SourceType, DestType,
5907 Initializer->isGLValue()),
5908 DestType);
5909 return;
5910 }
5911
5912 // - Otherwise, the initial value of the object being initialized is the
5913 // (possibly converted) value of the initializer expression. Standard
5914 // conversions (Clause 4) will be used, if necessary, to convert the
5915 // initializer expression to the cv-unqualified version of the
5916 // destination type; no user-defined conversions are considered.
5917
5918 ImplicitConversionSequence ICS
5919 = S.TryImplicitConversion(Initializer, DestType,
5920 /*SuppressUserConversions*/true,
5921 Sema::AllowedExplicit::None,
5922 /*InOverloadResolution*/ false,
5923 /*CStyle=*/Kind.isCStyleOrFunctionalCast(),
5924 allowObjCWritebackConversion);
5925
5926 if (ICS.isStandard() &&
5927 ICS.Standard.Second == ICK_Writeback_Conversion) {
5928 // Objective-C ARC writeback conversion.
5929
5930 // We should copy unless we're passing to an argument explicitly
5931 // marked 'out'.
5932 bool ShouldCopy = true;
5933 if (ParmVarDecl *Param = cast_or_null<ParmVarDecl>(Entity.getDecl()))
5934 ShouldCopy = (Param->getObjCDeclQualifier() != ParmVarDecl::OBJC_TQ_Out);
5935
5936 // If there was an lvalue adjustment, add it as a separate conversion.
5937 if (ICS.Standard.First == ICK_Array_To_Pointer ||
5938 ICS.Standard.First == ICK_Lvalue_To_Rvalue) {
5939 ImplicitConversionSequence LvalueICS;
5940 LvalueICS.setStandard();
5941 LvalueICS.Standard.setAsIdentityConversion();
5942 LvalueICS.Standard.setAllToTypes(ICS.Standard.getToType(0));
5943 LvalueICS.Standard.First = ICS.Standard.First;
5944 AddConversionSequenceStep(LvalueICS, ICS.Standard.getToType(0));
5945 }
5946
5947 AddPassByIndirectCopyRestoreStep(DestType, ShouldCopy);
5948 } else if (ICS.isBad()) {
5949 DeclAccessPair dap;
5950 if (isLibstdcxxPointerReturnFalseHack(S, Entity, Initializer)) {
5951 AddZeroInitializationStep(Entity.getType());
5952 } else if (Initializer->getType() == Context.OverloadTy &&
5953 !S.ResolveAddressOfOverloadedFunction(Initializer, DestType,
5954 false, dap))
5955 SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
5956 else if (Initializer->getType()->isFunctionType() &&
5957 isExprAnUnaddressableFunction(S, Initializer))
5958 SetFailed(InitializationSequence::FK_AddressOfUnaddressableFunction);
5959 else
5960 SetFailed(InitializationSequence::FK_ConversionFailed);
5961 } else {
5962 AddConversionSequenceStep(ICS, DestType, TopLevelOfInitList);
5963
5964 MaybeProduceObjCObject(S, *this, Entity);
5965 }
5966 }
5967
~InitializationSequence()5968 InitializationSequence::~InitializationSequence() {
5969 for (auto &S : Steps)
5970 S.Destroy();
5971 }
5972
5973 //===----------------------------------------------------------------------===//
5974 // Perform initialization
5975 //===----------------------------------------------------------------------===//
5976 static Sema::AssignmentAction
getAssignmentAction(const InitializedEntity & Entity,bool Diagnose=false)5977 getAssignmentAction(const InitializedEntity &Entity, bool Diagnose = false) {
5978 switch(Entity.getKind()) {
5979 case InitializedEntity::EK_Variable:
5980 case InitializedEntity::EK_New:
5981 case InitializedEntity::EK_Exception:
5982 case InitializedEntity::EK_Base:
5983 case InitializedEntity::EK_Delegating:
5984 return Sema::AA_Initializing;
5985
5986 case InitializedEntity::EK_Parameter:
5987 if (Entity.getDecl() &&
5988 isa<ObjCMethodDecl>(Entity.getDecl()->getDeclContext()))
5989 return Sema::AA_Sending;
5990
5991 return Sema::AA_Passing;
5992
5993 case InitializedEntity::EK_Parameter_CF_Audited:
5994 if (Entity.getDecl() &&
5995 isa<ObjCMethodDecl>(Entity.getDecl()->getDeclContext()))
5996 return Sema::AA_Sending;
5997
5998 return !Diagnose ? Sema::AA_Passing : Sema::AA_Passing_CFAudited;
5999
6000 case InitializedEntity::EK_Result:
6001 case InitializedEntity::EK_StmtExprResult: // FIXME: Not quite right.
6002 return Sema::AA_Returning;
6003
6004 case InitializedEntity::EK_Temporary:
6005 case InitializedEntity::EK_RelatedResult:
6006 // FIXME: Can we tell apart casting vs. converting?
6007 return Sema::AA_Casting;
6008
6009 case InitializedEntity::EK_TemplateParameter:
6010 // This is really initialization, but refer to it as conversion for
6011 // consistency with CheckConvertedConstantExpression.
6012 return Sema::AA_Converting;
6013
6014 case InitializedEntity::EK_Member:
6015 case InitializedEntity::EK_Binding:
6016 case InitializedEntity::EK_ArrayElement:
6017 case InitializedEntity::EK_VectorElement:
6018 case InitializedEntity::EK_ComplexElement:
6019 case InitializedEntity::EK_BlockElement:
6020 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6021 case InitializedEntity::EK_LambdaCapture:
6022 case InitializedEntity::EK_CompoundLiteralInit:
6023 return Sema::AA_Initializing;
6024 }
6025
6026 llvm_unreachable("Invalid EntityKind!");
6027 }
6028
6029 /// Whether we should bind a created object as a temporary when
6030 /// initializing the given entity.
shouldBindAsTemporary(const InitializedEntity & Entity)6031 static bool shouldBindAsTemporary(const InitializedEntity &Entity) {
6032 switch (Entity.getKind()) {
6033 case InitializedEntity::EK_ArrayElement:
6034 case InitializedEntity::EK_Member:
6035 case InitializedEntity::EK_Result:
6036 case InitializedEntity::EK_StmtExprResult:
6037 case InitializedEntity::EK_New:
6038 case InitializedEntity::EK_Variable:
6039 case InitializedEntity::EK_Base:
6040 case InitializedEntity::EK_Delegating:
6041 case InitializedEntity::EK_VectorElement:
6042 case InitializedEntity::EK_ComplexElement:
6043 case InitializedEntity::EK_Exception:
6044 case InitializedEntity::EK_BlockElement:
6045 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6046 case InitializedEntity::EK_LambdaCapture:
6047 case InitializedEntity::EK_CompoundLiteralInit:
6048 case InitializedEntity::EK_TemplateParameter:
6049 return false;
6050
6051 case InitializedEntity::EK_Parameter:
6052 case InitializedEntity::EK_Parameter_CF_Audited:
6053 case InitializedEntity::EK_Temporary:
6054 case InitializedEntity::EK_RelatedResult:
6055 case InitializedEntity::EK_Binding:
6056 return true;
6057 }
6058
6059 llvm_unreachable("missed an InitializedEntity kind?");
6060 }
6061
6062 /// Whether the given entity, when initialized with an object
6063 /// created for that initialization, requires destruction.
shouldDestroyEntity(const InitializedEntity & Entity)6064 static bool shouldDestroyEntity(const InitializedEntity &Entity) {
6065 switch (Entity.getKind()) {
6066 case InitializedEntity::EK_Result:
6067 case InitializedEntity::EK_StmtExprResult:
6068 case InitializedEntity::EK_New:
6069 case InitializedEntity::EK_Base:
6070 case InitializedEntity::EK_Delegating:
6071 case InitializedEntity::EK_VectorElement:
6072 case InitializedEntity::EK_ComplexElement:
6073 case InitializedEntity::EK_BlockElement:
6074 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6075 case InitializedEntity::EK_LambdaCapture:
6076 return false;
6077
6078 case InitializedEntity::EK_Member:
6079 case InitializedEntity::EK_Binding:
6080 case InitializedEntity::EK_Variable:
6081 case InitializedEntity::EK_Parameter:
6082 case InitializedEntity::EK_Parameter_CF_Audited:
6083 case InitializedEntity::EK_TemplateParameter:
6084 case InitializedEntity::EK_Temporary:
6085 case InitializedEntity::EK_ArrayElement:
6086 case InitializedEntity::EK_Exception:
6087 case InitializedEntity::EK_CompoundLiteralInit:
6088 case InitializedEntity::EK_RelatedResult:
6089 return true;
6090 }
6091
6092 llvm_unreachable("missed an InitializedEntity kind?");
6093 }
6094
6095 /// Get the location at which initialization diagnostics should appear.
getInitializationLoc(const InitializedEntity & Entity,Expr * Initializer)6096 static SourceLocation getInitializationLoc(const InitializedEntity &Entity,
6097 Expr *Initializer) {
6098 switch (Entity.getKind()) {
6099 case InitializedEntity::EK_Result:
6100 case InitializedEntity::EK_StmtExprResult:
6101 return Entity.getReturnLoc();
6102
6103 case InitializedEntity::EK_Exception:
6104 return Entity.getThrowLoc();
6105
6106 case InitializedEntity::EK_Variable:
6107 case InitializedEntity::EK_Binding:
6108 return Entity.getDecl()->getLocation();
6109
6110 case InitializedEntity::EK_LambdaCapture:
6111 return Entity.getCaptureLoc();
6112
6113 case InitializedEntity::EK_ArrayElement:
6114 case InitializedEntity::EK_Member:
6115 case InitializedEntity::EK_Parameter:
6116 case InitializedEntity::EK_Parameter_CF_Audited:
6117 case InitializedEntity::EK_TemplateParameter:
6118 case InitializedEntity::EK_Temporary:
6119 case InitializedEntity::EK_New:
6120 case InitializedEntity::EK_Base:
6121 case InitializedEntity::EK_Delegating:
6122 case InitializedEntity::EK_VectorElement:
6123 case InitializedEntity::EK_ComplexElement:
6124 case InitializedEntity::EK_BlockElement:
6125 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6126 case InitializedEntity::EK_CompoundLiteralInit:
6127 case InitializedEntity::EK_RelatedResult:
6128 return Initializer->getBeginLoc();
6129 }
6130 llvm_unreachable("missed an InitializedEntity kind?");
6131 }
6132
6133 /// Make a (potentially elidable) temporary copy of the object
6134 /// provided by the given initializer by calling the appropriate copy
6135 /// constructor.
6136 ///
6137 /// \param S The Sema object used for type-checking.
6138 ///
6139 /// \param T The type of the temporary object, which must either be
6140 /// the type of the initializer expression or a superclass thereof.
6141 ///
6142 /// \param Entity The entity being initialized.
6143 ///
6144 /// \param CurInit The initializer expression.
6145 ///
6146 /// \param IsExtraneousCopy Whether this is an "extraneous" copy that
6147 /// is permitted in C++03 (but not C++0x) when binding a reference to
6148 /// an rvalue.
6149 ///
6150 /// \returns An expression that copies the initializer expression into
6151 /// a temporary object, or an error expression if a copy could not be
6152 /// created.
CopyObject(Sema & S,QualType T,const InitializedEntity & Entity,ExprResult CurInit,bool IsExtraneousCopy)6153 static ExprResult CopyObject(Sema &S,
6154 QualType T,
6155 const InitializedEntity &Entity,
6156 ExprResult CurInit,
6157 bool IsExtraneousCopy) {
6158 if (CurInit.isInvalid())
6159 return CurInit;
6160 // Determine which class type we're copying to.
6161 Expr *CurInitExpr = (Expr *)CurInit.get();
6162 CXXRecordDecl *Class = nullptr;
6163 if (const RecordType *Record = T->getAs<RecordType>())
6164 Class = cast<CXXRecordDecl>(Record->getDecl());
6165 if (!Class)
6166 return CurInit;
6167
6168 SourceLocation Loc = getInitializationLoc(Entity, CurInit.get());
6169
6170 // Make sure that the type we are copying is complete.
6171 if (S.RequireCompleteType(Loc, T, diag::err_temp_copy_incomplete))
6172 return CurInit;
6173
6174 // Perform overload resolution using the class's constructors. Per
6175 // C++11 [dcl.init]p16, second bullet for class types, this initialization
6176 // is direct-initialization.
6177 OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
6178 DeclContext::lookup_result Ctors = S.LookupConstructors(Class);
6179
6180 OverloadCandidateSet::iterator Best;
6181 switch (ResolveConstructorOverload(
6182 S, Loc, CurInitExpr, CandidateSet, T, Ctors, Best,
6183 /*CopyInitializing=*/false, /*AllowExplicit=*/true,
6184 /*OnlyListConstructors=*/false, /*IsListInit=*/false,
6185 /*SecondStepOfCopyInit=*/true)) {
6186 case OR_Success:
6187 break;
6188
6189 case OR_No_Viable_Function:
6190 CandidateSet.NoteCandidates(
6191 PartialDiagnosticAt(
6192 Loc, S.PDiag(IsExtraneousCopy && !S.isSFINAEContext()
6193 ? diag::ext_rvalue_to_reference_temp_copy_no_viable
6194 : diag::err_temp_copy_no_viable)
6195 << (int)Entity.getKind() << CurInitExpr->getType()
6196 << CurInitExpr->getSourceRange()),
6197 S, OCD_AllCandidates, CurInitExpr);
6198 if (!IsExtraneousCopy || S.isSFINAEContext())
6199 return ExprError();
6200 return CurInit;
6201
6202 case OR_Ambiguous:
6203 CandidateSet.NoteCandidates(
6204 PartialDiagnosticAt(Loc, S.PDiag(diag::err_temp_copy_ambiguous)
6205 << (int)Entity.getKind()
6206 << CurInitExpr->getType()
6207 << CurInitExpr->getSourceRange()),
6208 S, OCD_AmbiguousCandidates, CurInitExpr);
6209 return ExprError();
6210
6211 case OR_Deleted:
6212 S.Diag(Loc, diag::err_temp_copy_deleted)
6213 << (int)Entity.getKind() << CurInitExpr->getType()
6214 << CurInitExpr->getSourceRange();
6215 S.NoteDeletedFunction(Best->Function);
6216 return ExprError();
6217 }
6218
6219 bool HadMultipleCandidates = CandidateSet.size() > 1;
6220
6221 CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Best->Function);
6222 SmallVector<Expr*, 8> ConstructorArgs;
6223 CurInit.get(); // Ownership transferred into MultiExprArg, below.
6224
6225 S.CheckConstructorAccess(Loc, Constructor, Best->FoundDecl, Entity,
6226 IsExtraneousCopy);
6227
6228 if (IsExtraneousCopy) {
6229 // If this is a totally extraneous copy for C++03 reference
6230 // binding purposes, just return the original initialization
6231 // expression. We don't generate an (elided) copy operation here
6232 // because doing so would require us to pass down a flag to avoid
6233 // infinite recursion, where each step adds another extraneous,
6234 // elidable copy.
6235
6236 // Instantiate the default arguments of any extra parameters in
6237 // the selected copy constructor, as if we were going to create a
6238 // proper call to the copy constructor.
6239 for (unsigned I = 1, N = Constructor->getNumParams(); I != N; ++I) {
6240 ParmVarDecl *Parm = Constructor->getParamDecl(I);
6241 if (S.RequireCompleteType(Loc, Parm->getType(),
6242 diag::err_call_incomplete_argument))
6243 break;
6244
6245 // Build the default argument expression; we don't actually care
6246 // if this succeeds or not, because this routine will complain
6247 // if there was a problem.
6248 S.BuildCXXDefaultArgExpr(Loc, Constructor, Parm);
6249 }
6250
6251 return CurInitExpr;
6252 }
6253
6254 // Determine the arguments required to actually perform the
6255 // constructor call (we might have derived-to-base conversions, or
6256 // the copy constructor may have default arguments).
6257 if (S.CompleteConstructorCall(Constructor, CurInitExpr, Loc, ConstructorArgs))
6258 return ExprError();
6259
6260 // C++0x [class.copy]p32:
6261 // When certain criteria are met, an implementation is allowed to
6262 // omit the copy/move construction of a class object, even if the
6263 // copy/move constructor and/or destructor for the object have
6264 // side effects. [...]
6265 // - when a temporary class object that has not been bound to a
6266 // reference (12.2) would be copied/moved to a class object
6267 // with the same cv-unqualified type, the copy/move operation
6268 // can be omitted by constructing the temporary object
6269 // directly into the target of the omitted copy/move
6270 //
6271 // Note that the other three bullets are handled elsewhere. Copy
6272 // elision for return statements and throw expressions are handled as part
6273 // of constructor initialization, while copy elision for exception handlers
6274 // is handled by the run-time.
6275 //
6276 // FIXME: If the function parameter is not the same type as the temporary, we
6277 // should still be able to elide the copy, but we don't have a way to
6278 // represent in the AST how much should be elided in this case.
6279 bool Elidable =
6280 CurInitExpr->isTemporaryObject(S.Context, Class) &&
6281 S.Context.hasSameUnqualifiedType(
6282 Best->Function->getParamDecl(0)->getType().getNonReferenceType(),
6283 CurInitExpr->getType());
6284
6285 // Actually perform the constructor call.
6286 CurInit = S.BuildCXXConstructExpr(Loc, T, Best->FoundDecl, Constructor,
6287 Elidable,
6288 ConstructorArgs,
6289 HadMultipleCandidates,
6290 /*ListInit*/ false,
6291 /*StdInitListInit*/ false,
6292 /*ZeroInit*/ false,
6293 CXXConstructExpr::CK_Complete,
6294 SourceRange());
6295
6296 // If we're supposed to bind temporaries, do so.
6297 if (!CurInit.isInvalid() && shouldBindAsTemporary(Entity))
6298 CurInit = S.MaybeBindToTemporary(CurInit.getAs<Expr>());
6299 return CurInit;
6300 }
6301
6302 /// Check whether elidable copy construction for binding a reference to
6303 /// a temporary would have succeeded if we were building in C++98 mode, for
6304 /// -Wc++98-compat.
CheckCXX98CompatAccessibleCopy(Sema & S,const InitializedEntity & Entity,Expr * CurInitExpr)6305 static void CheckCXX98CompatAccessibleCopy(Sema &S,
6306 const InitializedEntity &Entity,
6307 Expr *CurInitExpr) {
6308 assert(S.getLangOpts().CPlusPlus11);
6309
6310 const RecordType *Record = CurInitExpr->getType()->getAs<RecordType>();
6311 if (!Record)
6312 return;
6313
6314 SourceLocation Loc = getInitializationLoc(Entity, CurInitExpr);
6315 if (S.Diags.isIgnored(diag::warn_cxx98_compat_temp_copy, Loc))
6316 return;
6317
6318 // Find constructors which would have been considered.
6319 OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
6320 DeclContext::lookup_result Ctors =
6321 S.LookupConstructors(cast<CXXRecordDecl>(Record->getDecl()));
6322
6323 // Perform overload resolution.
6324 OverloadCandidateSet::iterator Best;
6325 OverloadingResult OR = ResolveConstructorOverload(
6326 S, Loc, CurInitExpr, CandidateSet, CurInitExpr->getType(), Ctors, Best,
6327 /*CopyInitializing=*/false, /*AllowExplicit=*/true,
6328 /*OnlyListConstructors=*/false, /*IsListInit=*/false,
6329 /*SecondStepOfCopyInit=*/true);
6330
6331 PartialDiagnostic Diag = S.PDiag(diag::warn_cxx98_compat_temp_copy)
6332 << OR << (int)Entity.getKind() << CurInitExpr->getType()
6333 << CurInitExpr->getSourceRange();
6334
6335 switch (OR) {
6336 case OR_Success:
6337 S.CheckConstructorAccess(Loc, cast<CXXConstructorDecl>(Best->Function),
6338 Best->FoundDecl, Entity, Diag);
6339 // FIXME: Check default arguments as far as that's possible.
6340 break;
6341
6342 case OR_No_Viable_Function:
6343 CandidateSet.NoteCandidates(PartialDiagnosticAt(Loc, Diag), S,
6344 OCD_AllCandidates, CurInitExpr);
6345 break;
6346
6347 case OR_Ambiguous:
6348 CandidateSet.NoteCandidates(PartialDiagnosticAt(Loc, Diag), S,
6349 OCD_AmbiguousCandidates, CurInitExpr);
6350 break;
6351
6352 case OR_Deleted:
6353 S.Diag(Loc, Diag);
6354 S.NoteDeletedFunction(Best->Function);
6355 break;
6356 }
6357 }
6358
PrintInitLocationNote(Sema & S,const InitializedEntity & Entity)6359 void InitializationSequence::PrintInitLocationNote(Sema &S,
6360 const InitializedEntity &Entity) {
6361 if (Entity.isParamOrTemplateParamKind() && Entity.getDecl()) {
6362 if (Entity.getDecl()->getLocation().isInvalid())
6363 return;
6364
6365 if (Entity.getDecl()->getDeclName())
6366 S.Diag(Entity.getDecl()->getLocation(), diag::note_parameter_named_here)
6367 << Entity.getDecl()->getDeclName();
6368 else
6369 S.Diag(Entity.getDecl()->getLocation(), diag::note_parameter_here);
6370 }
6371 else if (Entity.getKind() == InitializedEntity::EK_RelatedResult &&
6372 Entity.getMethodDecl())
6373 S.Diag(Entity.getMethodDecl()->getLocation(),
6374 diag::note_method_return_type_change)
6375 << Entity.getMethodDecl()->getDeclName();
6376 }
6377
6378 /// Returns true if the parameters describe a constructor initialization of
6379 /// an explicit temporary object, e.g. "Point(x, y)".
isExplicitTemporary(const InitializedEntity & Entity,const InitializationKind & Kind,unsigned NumArgs)6380 static bool isExplicitTemporary(const InitializedEntity &Entity,
6381 const InitializationKind &Kind,
6382 unsigned NumArgs) {
6383 switch (Entity.getKind()) {
6384 case InitializedEntity::EK_Temporary:
6385 case InitializedEntity::EK_CompoundLiteralInit:
6386 case InitializedEntity::EK_RelatedResult:
6387 break;
6388 default:
6389 return false;
6390 }
6391
6392 switch (Kind.getKind()) {
6393 case InitializationKind::IK_DirectList:
6394 return true;
6395 // FIXME: Hack to work around cast weirdness.
6396 case InitializationKind::IK_Direct:
6397 case InitializationKind::IK_Value:
6398 return NumArgs != 1;
6399 default:
6400 return false;
6401 }
6402 }
6403
6404 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)6405 PerformConstructorInitialization(Sema &S,
6406 const InitializedEntity &Entity,
6407 const InitializationKind &Kind,
6408 MultiExprArg Args,
6409 const InitializationSequence::Step& Step,
6410 bool &ConstructorInitRequiresZeroInit,
6411 bool IsListInitialization,
6412 bool IsStdInitListInitialization,
6413 SourceLocation LBraceLoc,
6414 SourceLocation RBraceLoc) {
6415 unsigned NumArgs = Args.size();
6416 CXXConstructorDecl *Constructor
6417 = cast<CXXConstructorDecl>(Step.Function.Function);
6418 bool HadMultipleCandidates = Step.Function.HadMultipleCandidates;
6419
6420 // Build a call to the selected constructor.
6421 SmallVector<Expr*, 8> ConstructorArgs;
6422 SourceLocation Loc = (Kind.isCopyInit() && Kind.getEqualLoc().isValid())
6423 ? Kind.getEqualLoc()
6424 : Kind.getLocation();
6425
6426 if (Kind.getKind() == InitializationKind::IK_Default) {
6427 // Force even a trivial, implicit default constructor to be
6428 // semantically checked. We do this explicitly because we don't build
6429 // the definition for completely trivial constructors.
6430 assert(Constructor->getParent() && "No parent class for constructor.");
6431 if (Constructor->isDefaulted() && Constructor->isDefaultConstructor() &&
6432 Constructor->isTrivial() && !Constructor->isUsed(false)) {
6433 S.runWithSufficientStackSpace(Loc, [&] {
6434 S.DefineImplicitDefaultConstructor(Loc, Constructor);
6435 });
6436 }
6437 }
6438
6439 ExprResult CurInit((Expr *)nullptr);
6440
6441 // C++ [over.match.copy]p1:
6442 // - When initializing a temporary to be bound to the first parameter
6443 // of a constructor that takes a reference to possibly cv-qualified
6444 // T as its first argument, called with a single argument in the
6445 // context of direct-initialization, explicit conversion functions
6446 // are also considered.
6447 bool AllowExplicitConv =
6448 Kind.AllowExplicit() && !Kind.isCopyInit() && Args.size() == 1 &&
6449 hasCopyOrMoveCtorParam(S.Context,
6450 getConstructorInfo(Step.Function.FoundDecl));
6451
6452 // Determine the arguments required to actually perform the constructor
6453 // call.
6454 if (S.CompleteConstructorCall(Constructor, Args,
6455 Loc, ConstructorArgs,
6456 AllowExplicitConv,
6457 IsListInitialization))
6458 return ExprError();
6459
6460
6461 if (isExplicitTemporary(Entity, Kind, NumArgs)) {
6462 // An explicitly-constructed temporary, e.g., X(1, 2).
6463 if (S.DiagnoseUseOfDecl(Constructor, Loc))
6464 return ExprError();
6465
6466 TypeSourceInfo *TSInfo = Entity.getTypeSourceInfo();
6467 if (!TSInfo)
6468 TSInfo = S.Context.getTrivialTypeSourceInfo(Entity.getType(), Loc);
6469 SourceRange ParenOrBraceRange =
6470 (Kind.getKind() == InitializationKind::IK_DirectList)
6471 ? SourceRange(LBraceLoc, RBraceLoc)
6472 : Kind.getParenOrBraceRange();
6473
6474 if (auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(
6475 Step.Function.FoundDecl.getDecl())) {
6476 Constructor = S.findInheritingConstructor(Loc, Constructor, Shadow);
6477 if (S.DiagnoseUseOfDecl(Constructor, Loc))
6478 return ExprError();
6479 }
6480 S.MarkFunctionReferenced(Loc, Constructor);
6481
6482 CurInit = S.CheckForImmediateInvocation(
6483 CXXTemporaryObjectExpr::Create(
6484 S.Context, Constructor,
6485 Entity.getType().getNonLValueExprType(S.Context), TSInfo,
6486 ConstructorArgs, ParenOrBraceRange, HadMultipleCandidates,
6487 IsListInitialization, IsStdInitListInitialization,
6488 ConstructorInitRequiresZeroInit),
6489 Constructor);
6490 } else {
6491 CXXConstructExpr::ConstructionKind ConstructKind =
6492 CXXConstructExpr::CK_Complete;
6493
6494 if (Entity.getKind() == InitializedEntity::EK_Base) {
6495 ConstructKind = Entity.getBaseSpecifier()->isVirtual() ?
6496 CXXConstructExpr::CK_VirtualBase :
6497 CXXConstructExpr::CK_NonVirtualBase;
6498 } else if (Entity.getKind() == InitializedEntity::EK_Delegating) {
6499 ConstructKind = CXXConstructExpr::CK_Delegating;
6500 }
6501
6502 // Only get the parenthesis or brace range if it is a list initialization or
6503 // direct construction.
6504 SourceRange ParenOrBraceRange;
6505 if (IsListInitialization)
6506 ParenOrBraceRange = SourceRange(LBraceLoc, RBraceLoc);
6507 else if (Kind.getKind() == InitializationKind::IK_Direct)
6508 ParenOrBraceRange = Kind.getParenOrBraceRange();
6509
6510 // If the entity allows NRVO, mark the construction as elidable
6511 // unconditionally.
6512 if (Entity.allowsNRVO())
6513 CurInit = S.BuildCXXConstructExpr(Loc, Step.Type,
6514 Step.Function.FoundDecl,
6515 Constructor, /*Elidable=*/true,
6516 ConstructorArgs,
6517 HadMultipleCandidates,
6518 IsListInitialization,
6519 IsStdInitListInitialization,
6520 ConstructorInitRequiresZeroInit,
6521 ConstructKind,
6522 ParenOrBraceRange);
6523 else
6524 CurInit = S.BuildCXXConstructExpr(Loc, Step.Type,
6525 Step.Function.FoundDecl,
6526 Constructor,
6527 ConstructorArgs,
6528 HadMultipleCandidates,
6529 IsListInitialization,
6530 IsStdInitListInitialization,
6531 ConstructorInitRequiresZeroInit,
6532 ConstructKind,
6533 ParenOrBraceRange);
6534 }
6535 if (CurInit.isInvalid())
6536 return ExprError();
6537
6538 // Only check access if all of that succeeded.
6539 S.CheckConstructorAccess(Loc, Constructor, Step.Function.FoundDecl, Entity);
6540 if (S.DiagnoseUseOfDecl(Step.Function.FoundDecl, Loc))
6541 return ExprError();
6542
6543 if (const ArrayType *AT = S.Context.getAsArrayType(Entity.getType()))
6544 if (checkDestructorReference(S.Context.getBaseElementType(AT), Loc, S))
6545 return ExprError();
6546
6547 if (shouldBindAsTemporary(Entity))
6548 CurInit = S.MaybeBindToTemporary(CurInit.get());
6549
6550 return CurInit;
6551 }
6552
6553 namespace {
6554 enum LifetimeKind {
6555 /// The lifetime of a temporary bound to this entity ends at the end of the
6556 /// full-expression, and that's (probably) fine.
6557 LK_FullExpression,
6558
6559 /// The lifetime of a temporary bound to this entity is extended to the
6560 /// lifeitme of the entity itself.
6561 LK_Extended,
6562
6563 /// The lifetime of a temporary bound to this entity probably ends too soon,
6564 /// because the entity is allocated in a new-expression.
6565 LK_New,
6566
6567 /// The lifetime of a temporary bound to this entity ends too soon, because
6568 /// the entity is a return object.
6569 LK_Return,
6570
6571 /// The lifetime of a temporary bound to this entity ends too soon, because
6572 /// the entity is the result of a statement expression.
6573 LK_StmtExprResult,
6574
6575 /// This is a mem-initializer: if it would extend a temporary (other than via
6576 /// a default member initializer), the program is ill-formed.
6577 LK_MemInitializer,
6578 };
6579 using LifetimeResult =
6580 llvm::PointerIntPair<const InitializedEntity *, 3, LifetimeKind>;
6581 }
6582
6583 /// Determine the declaration which an initialized entity ultimately refers to,
6584 /// for the purpose of lifetime-extending a temporary bound to a reference in
6585 /// the initialization of \p Entity.
getEntityLifetime(const InitializedEntity * Entity,const InitializedEntity * InitField=nullptr)6586 static LifetimeResult getEntityLifetime(
6587 const InitializedEntity *Entity,
6588 const InitializedEntity *InitField = nullptr) {
6589 // C++11 [class.temporary]p5:
6590 switch (Entity->getKind()) {
6591 case InitializedEntity::EK_Variable:
6592 // The temporary [...] persists for the lifetime of the reference
6593 return {Entity, LK_Extended};
6594
6595 case InitializedEntity::EK_Member:
6596 // For subobjects, we look at the complete object.
6597 if (Entity->getParent())
6598 return getEntityLifetime(Entity->getParent(), Entity);
6599
6600 // except:
6601 // C++17 [class.base.init]p8:
6602 // A temporary expression bound to a reference member in a
6603 // mem-initializer is ill-formed.
6604 // C++17 [class.base.init]p11:
6605 // A temporary expression bound to a reference member from a
6606 // default member initializer is ill-formed.
6607 //
6608 // The context of p11 and its example suggest that it's only the use of a
6609 // default member initializer from a constructor that makes the program
6610 // ill-formed, not its mere existence, and that it can even be used by
6611 // aggregate initialization.
6612 return {Entity, Entity->isDefaultMemberInitializer() ? LK_Extended
6613 : LK_MemInitializer};
6614
6615 case InitializedEntity::EK_Binding:
6616 // Per [dcl.decomp]p3, the binding is treated as a variable of reference
6617 // type.
6618 return {Entity, LK_Extended};
6619
6620 case InitializedEntity::EK_Parameter:
6621 case InitializedEntity::EK_Parameter_CF_Audited:
6622 // -- A temporary bound to a reference parameter in a function call
6623 // persists until the completion of the full-expression containing
6624 // the call.
6625 return {nullptr, LK_FullExpression};
6626
6627 case InitializedEntity::EK_TemplateParameter:
6628 // FIXME: This will always be ill-formed; should we eagerly diagnose it here?
6629 return {nullptr, LK_FullExpression};
6630
6631 case InitializedEntity::EK_Result:
6632 // -- The lifetime of a temporary bound to the returned value in a
6633 // function return statement is not extended; the temporary is
6634 // destroyed at the end of the full-expression in the return statement.
6635 return {nullptr, LK_Return};
6636
6637 case InitializedEntity::EK_StmtExprResult:
6638 // FIXME: Should we lifetime-extend through the result of a statement
6639 // expression?
6640 return {nullptr, LK_StmtExprResult};
6641
6642 case InitializedEntity::EK_New:
6643 // -- A temporary bound to a reference in a new-initializer persists
6644 // until the completion of the full-expression containing the
6645 // new-initializer.
6646 return {nullptr, LK_New};
6647
6648 case InitializedEntity::EK_Temporary:
6649 case InitializedEntity::EK_CompoundLiteralInit:
6650 case InitializedEntity::EK_RelatedResult:
6651 // We don't yet know the storage duration of the surrounding temporary.
6652 // Assume it's got full-expression duration for now, it will patch up our
6653 // storage duration if that's not correct.
6654 return {nullptr, LK_FullExpression};
6655
6656 case InitializedEntity::EK_ArrayElement:
6657 // For subobjects, we look at the complete object.
6658 return getEntityLifetime(Entity->getParent(), InitField);
6659
6660 case InitializedEntity::EK_Base:
6661 // For subobjects, we look at the complete object.
6662 if (Entity->getParent())
6663 return getEntityLifetime(Entity->getParent(), InitField);
6664 return {InitField, LK_MemInitializer};
6665
6666 case InitializedEntity::EK_Delegating:
6667 // We can reach this case for aggregate initialization in a constructor:
6668 // struct A { int &&r; };
6669 // struct B : A { B() : A{0} {} };
6670 // In this case, use the outermost field decl as the context.
6671 return {InitField, LK_MemInitializer};
6672
6673 case InitializedEntity::EK_BlockElement:
6674 case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6675 case InitializedEntity::EK_LambdaCapture:
6676 case InitializedEntity::EK_VectorElement:
6677 case InitializedEntity::EK_ComplexElement:
6678 return {nullptr, LK_FullExpression};
6679
6680 case InitializedEntity::EK_Exception:
6681 // FIXME: Can we diagnose lifetime problems with exceptions?
6682 return {nullptr, LK_FullExpression};
6683 }
6684 llvm_unreachable("unknown entity kind");
6685 }
6686
6687 namespace {
6688 enum ReferenceKind {
6689 /// Lifetime would be extended by a reference binding to a temporary.
6690 RK_ReferenceBinding,
6691 /// Lifetime would be extended by a std::initializer_list object binding to
6692 /// its backing array.
6693 RK_StdInitializerList,
6694 };
6695
6696 /// A temporary or local variable. This will be one of:
6697 /// * A MaterializeTemporaryExpr.
6698 /// * A DeclRefExpr whose declaration is a local.
6699 /// * An AddrLabelExpr.
6700 /// * A BlockExpr for a block with captures.
6701 using Local = Expr*;
6702
6703 /// Expressions we stepped over when looking for the local state. Any steps
6704 /// that would inhibit lifetime extension or take us out of subexpressions of
6705 /// the initializer are included.
6706 struct IndirectLocalPathEntry {
6707 enum EntryKind {
6708 DefaultInit,
6709 AddressOf,
6710 VarInit,
6711 LValToRVal,
6712 LifetimeBoundCall,
6713 TemporaryCopy,
6714 LambdaCaptureInit,
6715 GslReferenceInit,
6716 GslPointerInit
6717 } Kind;
6718 Expr *E;
6719 union {
6720 const Decl *D = nullptr;
6721 const LambdaCapture *Capture;
6722 };
IndirectLocalPathEntry__anona4629a220511::IndirectLocalPathEntry6723 IndirectLocalPathEntry() {}
IndirectLocalPathEntry__anona4629a220511::IndirectLocalPathEntry6724 IndirectLocalPathEntry(EntryKind K, Expr *E) : Kind(K), E(E) {}
IndirectLocalPathEntry__anona4629a220511::IndirectLocalPathEntry6725 IndirectLocalPathEntry(EntryKind K, Expr *E, const Decl *D)
6726 : Kind(K), E(E), D(D) {}
IndirectLocalPathEntry__anona4629a220511::IndirectLocalPathEntry6727 IndirectLocalPathEntry(EntryKind K, Expr *E, const LambdaCapture *Capture)
6728 : Kind(K), E(E), Capture(Capture) {}
6729 };
6730
6731 using IndirectLocalPath = llvm::SmallVectorImpl<IndirectLocalPathEntry>;
6732
6733 struct RevertToOldSizeRAII {
6734 IndirectLocalPath &Path;
6735 unsigned OldSize = Path.size();
RevertToOldSizeRAII__anona4629a220511::RevertToOldSizeRAII6736 RevertToOldSizeRAII(IndirectLocalPath &Path) : Path(Path) {}
~RevertToOldSizeRAII__anona4629a220511::RevertToOldSizeRAII6737 ~RevertToOldSizeRAII() { Path.resize(OldSize); }
6738 };
6739
6740 using LocalVisitor = llvm::function_ref<bool(IndirectLocalPath &Path, Local L,
6741 ReferenceKind RK)>;
6742 }
6743
isVarOnPath(IndirectLocalPath & Path,VarDecl * VD)6744 static bool isVarOnPath(IndirectLocalPath &Path, VarDecl *VD) {
6745 for (auto E : Path)
6746 if (E.Kind == IndirectLocalPathEntry::VarInit && E.D == VD)
6747 return true;
6748 return false;
6749 }
6750
pathContainsInit(IndirectLocalPath & Path)6751 static bool pathContainsInit(IndirectLocalPath &Path) {
6752 return llvm::any_of(Path, [=](IndirectLocalPathEntry E) {
6753 return E.Kind == IndirectLocalPathEntry::DefaultInit ||
6754 E.Kind == IndirectLocalPathEntry::VarInit;
6755 });
6756 }
6757
6758 static void visitLocalsRetainedByInitializer(IndirectLocalPath &Path,
6759 Expr *Init, LocalVisitor Visit,
6760 bool RevisitSubinits,
6761 bool EnableLifetimeWarnings);
6762
6763 static void visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
6764 Expr *Init, ReferenceKind RK,
6765 LocalVisitor Visit,
6766 bool EnableLifetimeWarnings);
6767
isRecordWithAttr(QualType Type)6768 template <typename T> static bool isRecordWithAttr(QualType Type) {
6769 if (auto *RD = Type->getAsCXXRecordDecl())
6770 return RD->hasAttr<T>();
6771 return false;
6772 }
6773
6774 // Decl::isInStdNamespace will return false for iterators in some STL
6775 // implementations due to them being defined in a namespace outside of the std
6776 // namespace.
isInStlNamespace(const Decl * D)6777 static bool isInStlNamespace(const Decl *D) {
6778 const DeclContext *DC = D->getDeclContext();
6779 if (!DC)
6780 return false;
6781 if (const auto *ND = dyn_cast<NamespaceDecl>(DC))
6782 if (const IdentifierInfo *II = ND->getIdentifier()) {
6783 StringRef Name = II->getName();
6784 if (Name.size() >= 2 && Name.front() == '_' &&
6785 (Name[1] == '_' || isUppercase(Name[1])))
6786 return true;
6787 }
6788
6789 return DC->isStdNamespace();
6790 }
6791
shouldTrackImplicitObjectArg(const CXXMethodDecl * Callee)6792 static bool shouldTrackImplicitObjectArg(const CXXMethodDecl *Callee) {
6793 if (auto *Conv = dyn_cast_or_null<CXXConversionDecl>(Callee))
6794 if (isRecordWithAttr<PointerAttr>(Conv->getConversionType()))
6795 return true;
6796 if (!isInStlNamespace(Callee->getParent()))
6797 return false;
6798 if (!isRecordWithAttr<PointerAttr>(Callee->getThisObjectType()) &&
6799 !isRecordWithAttr<OwnerAttr>(Callee->getThisObjectType()))
6800 return false;
6801 if (Callee->getReturnType()->isPointerType() ||
6802 isRecordWithAttr<PointerAttr>(Callee->getReturnType())) {
6803 if (!Callee->getIdentifier())
6804 return false;
6805 return llvm::StringSwitch<bool>(Callee->getName())
6806 .Cases("begin", "rbegin", "cbegin", "crbegin", true)
6807 .Cases("end", "rend", "cend", "crend", true)
6808 .Cases("c_str", "data", "get", true)
6809 // Map and set types.
6810 .Cases("find", "equal_range", "lower_bound", "upper_bound", true)
6811 .Default(false);
6812 } else if (Callee->getReturnType()->isReferenceType()) {
6813 if (!Callee->getIdentifier()) {
6814 auto OO = Callee->getOverloadedOperator();
6815 return OO == OverloadedOperatorKind::OO_Subscript ||
6816 OO == OverloadedOperatorKind::OO_Star;
6817 }
6818 return llvm::StringSwitch<bool>(Callee->getName())
6819 .Cases("front", "back", "at", "top", "value", true)
6820 .Default(false);
6821 }
6822 return false;
6823 }
6824
shouldTrackFirstArgument(const FunctionDecl * FD)6825 static bool shouldTrackFirstArgument(const FunctionDecl *FD) {
6826 if (!FD->getIdentifier() || FD->getNumParams() != 1)
6827 return false;
6828 const auto *RD = FD->getParamDecl(0)->getType()->getPointeeCXXRecordDecl();
6829 if (!FD->isInStdNamespace() || !RD || !RD->isInStdNamespace())
6830 return false;
6831 if (!isRecordWithAttr<PointerAttr>(QualType(RD->getTypeForDecl(), 0)) &&
6832 !isRecordWithAttr<OwnerAttr>(QualType(RD->getTypeForDecl(), 0)))
6833 return false;
6834 if (FD->getReturnType()->isPointerType() ||
6835 isRecordWithAttr<PointerAttr>(FD->getReturnType())) {
6836 return llvm::StringSwitch<bool>(FD->getName())
6837 .Cases("begin", "rbegin", "cbegin", "crbegin", true)
6838 .Cases("end", "rend", "cend", "crend", true)
6839 .Case("data", true)
6840 .Default(false);
6841 } else if (FD->getReturnType()->isReferenceType()) {
6842 return llvm::StringSwitch<bool>(FD->getName())
6843 .Cases("get", "any_cast", true)
6844 .Default(false);
6845 }
6846 return false;
6847 }
6848
handleGslAnnotatedTypes(IndirectLocalPath & Path,Expr * Call,LocalVisitor Visit)6849 static void handleGslAnnotatedTypes(IndirectLocalPath &Path, Expr *Call,
6850 LocalVisitor Visit) {
6851 auto VisitPointerArg = [&](const Decl *D, Expr *Arg, bool Value) {
6852 // We are not interested in the temporary base objects of gsl Pointers:
6853 // Temp().ptr; // Here ptr might not dangle.
6854 if (isa<MemberExpr>(Arg->IgnoreImpCasts()))
6855 return;
6856 // Once we initialized a value with a reference, it can no longer dangle.
6857 if (!Value) {
6858 for (auto It = Path.rbegin(), End = Path.rend(); It != End; ++It) {
6859 if (It->Kind == IndirectLocalPathEntry::GslReferenceInit)
6860 continue;
6861 if (It->Kind == IndirectLocalPathEntry::GslPointerInit)
6862 return;
6863 break;
6864 }
6865 }
6866 Path.push_back({Value ? IndirectLocalPathEntry::GslPointerInit
6867 : IndirectLocalPathEntry::GslReferenceInit,
6868 Arg, D});
6869 if (Arg->isGLValue())
6870 visitLocalsRetainedByReferenceBinding(Path, Arg, RK_ReferenceBinding,
6871 Visit,
6872 /*EnableLifetimeWarnings=*/true);
6873 else
6874 visitLocalsRetainedByInitializer(Path, Arg, Visit, true,
6875 /*EnableLifetimeWarnings=*/true);
6876 Path.pop_back();
6877 };
6878
6879 if (auto *MCE = dyn_cast<CXXMemberCallExpr>(Call)) {
6880 const auto *MD = cast_or_null<CXXMethodDecl>(MCE->getDirectCallee());
6881 if (MD && shouldTrackImplicitObjectArg(MD))
6882 VisitPointerArg(MD, MCE->getImplicitObjectArgument(),
6883 !MD->getReturnType()->isReferenceType());
6884 return;
6885 } else if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(Call)) {
6886 FunctionDecl *Callee = OCE->getDirectCallee();
6887 if (Callee && Callee->isCXXInstanceMember() &&
6888 shouldTrackImplicitObjectArg(cast<CXXMethodDecl>(Callee)))
6889 VisitPointerArg(Callee, OCE->getArg(0),
6890 !Callee->getReturnType()->isReferenceType());
6891 return;
6892 } else if (auto *CE = dyn_cast<CallExpr>(Call)) {
6893 FunctionDecl *Callee = CE->getDirectCallee();
6894 if (Callee && shouldTrackFirstArgument(Callee))
6895 VisitPointerArg(Callee, CE->getArg(0),
6896 !Callee->getReturnType()->isReferenceType());
6897 return;
6898 }
6899
6900 if (auto *CCE = dyn_cast<CXXConstructExpr>(Call)) {
6901 const auto *Ctor = CCE->getConstructor();
6902 const CXXRecordDecl *RD = Ctor->getParent();
6903 if (CCE->getNumArgs() > 0 && RD->hasAttr<PointerAttr>())
6904 VisitPointerArg(Ctor->getParamDecl(0), CCE->getArgs()[0], true);
6905 }
6906 }
6907
implicitObjectParamIsLifetimeBound(const FunctionDecl * FD)6908 static bool implicitObjectParamIsLifetimeBound(const FunctionDecl *FD) {
6909 const TypeSourceInfo *TSI = FD->getTypeSourceInfo();
6910 if (!TSI)
6911 return false;
6912 // Don't declare this variable in the second operand of the for-statement;
6913 // GCC miscompiles that by ending its lifetime before evaluating the
6914 // third operand. See gcc.gnu.org/PR86769.
6915 AttributedTypeLoc ATL;
6916 for (TypeLoc TL = TSI->getTypeLoc();
6917 (ATL = TL.getAsAdjusted<AttributedTypeLoc>());
6918 TL = ATL.getModifiedLoc()) {
6919 if (ATL.getAttrAs<LifetimeBoundAttr>())
6920 return true;
6921 }
6922
6923 // Assume that all assignment operators with a "normal" return type return
6924 // *this, that is, an lvalue reference that is the same type as the implicit
6925 // object parameter (or the LHS for a non-member operator$=).
6926 OverloadedOperatorKind OO = FD->getDeclName().getCXXOverloadedOperator();
6927 if (OO == OO_Equal || isCompoundAssignmentOperator(OO)) {
6928 QualType RetT = FD->getReturnType();
6929 if (RetT->isLValueReferenceType()) {
6930 ASTContext &Ctx = FD->getASTContext();
6931 QualType LHST;
6932 auto *MD = dyn_cast<CXXMethodDecl>(FD);
6933 if (MD && MD->isCXXInstanceMember())
6934 LHST = Ctx.getLValueReferenceType(MD->getThisObjectType());
6935 else
6936 LHST = MD->getParamDecl(0)->getType();
6937 if (Ctx.hasSameType(RetT, LHST))
6938 return true;
6939 }
6940 }
6941
6942 return false;
6943 }
6944
visitLifetimeBoundArguments(IndirectLocalPath & Path,Expr * Call,LocalVisitor Visit)6945 static void visitLifetimeBoundArguments(IndirectLocalPath &Path, Expr *Call,
6946 LocalVisitor Visit) {
6947 const FunctionDecl *Callee;
6948 ArrayRef<Expr*> Args;
6949
6950 if (auto *CE = dyn_cast<CallExpr>(Call)) {
6951 Callee = CE->getDirectCallee();
6952 Args = llvm::makeArrayRef(CE->getArgs(), CE->getNumArgs());
6953 } else {
6954 auto *CCE = cast<CXXConstructExpr>(Call);
6955 Callee = CCE->getConstructor();
6956 Args = llvm::makeArrayRef(CCE->getArgs(), CCE->getNumArgs());
6957 }
6958 if (!Callee)
6959 return;
6960
6961 Expr *ObjectArg = nullptr;
6962 if (isa<CXXOperatorCallExpr>(Call) && Callee->isCXXInstanceMember()) {
6963 ObjectArg = Args[0];
6964 Args = Args.slice(1);
6965 } else if (auto *MCE = dyn_cast<CXXMemberCallExpr>(Call)) {
6966 ObjectArg = MCE->getImplicitObjectArgument();
6967 }
6968
6969 auto VisitLifetimeBoundArg = [&](const Decl *D, Expr *Arg) {
6970 Path.push_back({IndirectLocalPathEntry::LifetimeBoundCall, Arg, D});
6971 if (Arg->isGLValue())
6972 visitLocalsRetainedByReferenceBinding(Path, Arg, RK_ReferenceBinding,
6973 Visit,
6974 /*EnableLifetimeWarnings=*/false);
6975 else
6976 visitLocalsRetainedByInitializer(Path, Arg, Visit, true,
6977 /*EnableLifetimeWarnings=*/false);
6978 Path.pop_back();
6979 };
6980
6981 if (ObjectArg && implicitObjectParamIsLifetimeBound(Callee))
6982 VisitLifetimeBoundArg(Callee, ObjectArg);
6983
6984 for (unsigned I = 0,
6985 N = std::min<unsigned>(Callee->getNumParams(), Args.size());
6986 I != N; ++I) {
6987 if (Callee->getParamDecl(I)->hasAttr<LifetimeBoundAttr>())
6988 VisitLifetimeBoundArg(Callee->getParamDecl(I), Args[I]);
6989 }
6990 }
6991
6992 /// Visit the locals that would be reachable through a reference bound to the
6993 /// glvalue expression \c Init.
visitLocalsRetainedByReferenceBinding(IndirectLocalPath & Path,Expr * Init,ReferenceKind RK,LocalVisitor Visit,bool EnableLifetimeWarnings)6994 static void visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
6995 Expr *Init, ReferenceKind RK,
6996 LocalVisitor Visit,
6997 bool EnableLifetimeWarnings) {
6998 RevertToOldSizeRAII RAII(Path);
6999
7000 // Walk past any constructs which we can lifetime-extend across.
7001 Expr *Old;
7002 do {
7003 Old = Init;
7004
7005 if (auto *FE = dyn_cast<FullExpr>(Init))
7006 Init = FE->getSubExpr();
7007
7008 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
7009 // If this is just redundant braces around an initializer, step over it.
7010 if (ILE->isTransparent())
7011 Init = ILE->getInit(0);
7012 }
7013
7014 // Step over any subobject adjustments; we may have a materialized
7015 // temporary inside them.
7016 Init = const_cast<Expr *>(Init->skipRValueSubobjectAdjustments());
7017
7018 // Per current approach for DR1376, look through casts to reference type
7019 // when performing lifetime extension.
7020 if (CastExpr *CE = dyn_cast<CastExpr>(Init))
7021 if (CE->getSubExpr()->isGLValue())
7022 Init = CE->getSubExpr();
7023
7024 // Per the current approach for DR1299, look through array element access
7025 // on array glvalues when performing lifetime extension.
7026 if (auto *ASE = dyn_cast<ArraySubscriptExpr>(Init)) {
7027 Init = ASE->getBase();
7028 auto *ICE = dyn_cast<ImplicitCastExpr>(Init);
7029 if (ICE && ICE->getCastKind() == CK_ArrayToPointerDecay)
7030 Init = ICE->getSubExpr();
7031 else
7032 // We can't lifetime extend through this but we might still find some
7033 // retained temporaries.
7034 return visitLocalsRetainedByInitializer(Path, Init, Visit, true,
7035 EnableLifetimeWarnings);
7036 }
7037
7038 // Step into CXXDefaultInitExprs so we can diagnose cases where a
7039 // constructor inherits one as an implicit mem-initializer.
7040 if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Init)) {
7041 Path.push_back(
7042 {IndirectLocalPathEntry::DefaultInit, DIE, DIE->getField()});
7043 Init = DIE->getExpr();
7044 }
7045 } while (Init != Old);
7046
7047 if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(Init)) {
7048 if (Visit(Path, Local(MTE), RK))
7049 visitLocalsRetainedByInitializer(Path, MTE->getSubExpr(), Visit, true,
7050 EnableLifetimeWarnings);
7051 }
7052
7053 if (isa<CallExpr>(Init)) {
7054 if (EnableLifetimeWarnings)
7055 handleGslAnnotatedTypes(Path, Init, Visit);
7056 return visitLifetimeBoundArguments(Path, Init, Visit);
7057 }
7058
7059 switch (Init->getStmtClass()) {
7060 case Stmt::DeclRefExprClass: {
7061 // If we find the name of a local non-reference parameter, we could have a
7062 // lifetime problem.
7063 auto *DRE = cast<DeclRefExpr>(Init);
7064 auto *VD = dyn_cast<VarDecl>(DRE->getDecl());
7065 if (VD && VD->hasLocalStorage() &&
7066 !DRE->refersToEnclosingVariableOrCapture()) {
7067 if (!VD->getType()->isReferenceType()) {
7068 Visit(Path, Local(DRE), RK);
7069 } else if (isa<ParmVarDecl>(DRE->getDecl())) {
7070 // The lifetime of a reference parameter is unknown; assume it's OK
7071 // for now.
7072 break;
7073 } else if (VD->getInit() && !isVarOnPath(Path, VD)) {
7074 Path.push_back({IndirectLocalPathEntry::VarInit, DRE, VD});
7075 visitLocalsRetainedByReferenceBinding(Path, VD->getInit(),
7076 RK_ReferenceBinding, Visit,
7077 EnableLifetimeWarnings);
7078 }
7079 }
7080 break;
7081 }
7082
7083 case Stmt::UnaryOperatorClass: {
7084 // The only unary operator that make sense to handle here
7085 // is Deref. All others don't resolve to a "name." This includes
7086 // handling all sorts of rvalues passed to a unary operator.
7087 const UnaryOperator *U = cast<UnaryOperator>(Init);
7088 if (U->getOpcode() == UO_Deref)
7089 visitLocalsRetainedByInitializer(Path, U->getSubExpr(), Visit, true,
7090 EnableLifetimeWarnings);
7091 break;
7092 }
7093
7094 case Stmt::OMPArraySectionExprClass: {
7095 visitLocalsRetainedByInitializer(Path,
7096 cast<OMPArraySectionExpr>(Init)->getBase(),
7097 Visit, true, EnableLifetimeWarnings);
7098 break;
7099 }
7100
7101 case Stmt::ConditionalOperatorClass:
7102 case Stmt::BinaryConditionalOperatorClass: {
7103 auto *C = cast<AbstractConditionalOperator>(Init);
7104 if (!C->getTrueExpr()->getType()->isVoidType())
7105 visitLocalsRetainedByReferenceBinding(Path, C->getTrueExpr(), RK, Visit,
7106 EnableLifetimeWarnings);
7107 if (!C->getFalseExpr()->getType()->isVoidType())
7108 visitLocalsRetainedByReferenceBinding(Path, C->getFalseExpr(), RK, Visit,
7109 EnableLifetimeWarnings);
7110 break;
7111 }
7112
7113 // FIXME: Visit the left-hand side of an -> or ->*.
7114
7115 default:
7116 break;
7117 }
7118 }
7119
7120 /// Visit the locals that would be reachable through an object initialized by
7121 /// the prvalue expression \c Init.
visitLocalsRetainedByInitializer(IndirectLocalPath & Path,Expr * Init,LocalVisitor Visit,bool RevisitSubinits,bool EnableLifetimeWarnings)7122 static void visitLocalsRetainedByInitializer(IndirectLocalPath &Path,
7123 Expr *Init, LocalVisitor Visit,
7124 bool RevisitSubinits,
7125 bool EnableLifetimeWarnings) {
7126 RevertToOldSizeRAII RAII(Path);
7127
7128 Expr *Old;
7129 do {
7130 Old = Init;
7131
7132 // Step into CXXDefaultInitExprs so we can diagnose cases where a
7133 // constructor inherits one as an implicit mem-initializer.
7134 if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Init)) {
7135 Path.push_back({IndirectLocalPathEntry::DefaultInit, DIE, DIE->getField()});
7136 Init = DIE->getExpr();
7137 }
7138
7139 if (auto *FE = dyn_cast<FullExpr>(Init))
7140 Init = FE->getSubExpr();
7141
7142 // Dig out the expression which constructs the extended temporary.
7143 Init = const_cast<Expr *>(Init->skipRValueSubobjectAdjustments());
7144
7145 if (CXXBindTemporaryExpr *BTE = dyn_cast<CXXBindTemporaryExpr>(Init))
7146 Init = BTE->getSubExpr();
7147
7148 Init = Init->IgnoreParens();
7149
7150 // Step over value-preserving rvalue casts.
7151 if (auto *CE = dyn_cast<CastExpr>(Init)) {
7152 switch (CE->getCastKind()) {
7153 case CK_LValueToRValue:
7154 // If we can match the lvalue to a const object, we can look at its
7155 // initializer.
7156 Path.push_back({IndirectLocalPathEntry::LValToRVal, CE});
7157 return visitLocalsRetainedByReferenceBinding(
7158 Path, Init, RK_ReferenceBinding,
7159 [&](IndirectLocalPath &Path, Local L, ReferenceKind RK) -> bool {
7160 if (auto *DRE = dyn_cast<DeclRefExpr>(L)) {
7161 auto *VD = dyn_cast<VarDecl>(DRE->getDecl());
7162 if (VD && VD->getType().isConstQualified() && VD->getInit() &&
7163 !isVarOnPath(Path, VD)) {
7164 Path.push_back({IndirectLocalPathEntry::VarInit, DRE, VD});
7165 visitLocalsRetainedByInitializer(Path, VD->getInit(), Visit, true,
7166 EnableLifetimeWarnings);
7167 }
7168 } else if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(L)) {
7169 if (MTE->getType().isConstQualified())
7170 visitLocalsRetainedByInitializer(Path, MTE->getSubExpr(), Visit,
7171 true, EnableLifetimeWarnings);
7172 }
7173 return false;
7174 }, EnableLifetimeWarnings);
7175
7176 // We assume that objects can be retained by pointers cast to integers,
7177 // but not if the integer is cast to floating-point type or to _Complex.
7178 // We assume that casts to 'bool' do not preserve enough information to
7179 // retain a local object.
7180 case CK_NoOp:
7181 case CK_BitCast:
7182 case CK_BaseToDerived:
7183 case CK_DerivedToBase:
7184 case CK_UncheckedDerivedToBase:
7185 case CK_Dynamic:
7186 case CK_ToUnion:
7187 case CK_UserDefinedConversion:
7188 case CK_ConstructorConversion:
7189 case CK_IntegralToPointer:
7190 case CK_PointerToIntegral:
7191 case CK_VectorSplat:
7192 case CK_IntegralCast:
7193 case CK_CPointerToObjCPointerCast:
7194 case CK_BlockPointerToObjCPointerCast:
7195 case CK_AnyPointerToBlockPointerCast:
7196 case CK_AddressSpaceConversion:
7197 break;
7198
7199 case CK_ArrayToPointerDecay:
7200 // Model array-to-pointer decay as taking the address of the array
7201 // lvalue.
7202 Path.push_back({IndirectLocalPathEntry::AddressOf, CE});
7203 return visitLocalsRetainedByReferenceBinding(Path, CE->getSubExpr(),
7204 RK_ReferenceBinding, Visit,
7205 EnableLifetimeWarnings);
7206
7207 default:
7208 return;
7209 }
7210
7211 Init = CE->getSubExpr();
7212 }
7213 } while (Old != Init);
7214
7215 // C++17 [dcl.init.list]p6:
7216 // initializing an initializer_list object from the array extends the
7217 // lifetime of the array exactly like binding a reference to a temporary.
7218 if (auto *ILE = dyn_cast<CXXStdInitializerListExpr>(Init))
7219 return visitLocalsRetainedByReferenceBinding(Path, ILE->getSubExpr(),
7220 RK_StdInitializerList, Visit,
7221 EnableLifetimeWarnings);
7222
7223 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
7224 // We already visited the elements of this initializer list while
7225 // performing the initialization. Don't visit them again unless we've
7226 // changed the lifetime of the initialized entity.
7227 if (!RevisitSubinits)
7228 return;
7229
7230 if (ILE->isTransparent())
7231 return visitLocalsRetainedByInitializer(Path, ILE->getInit(0), Visit,
7232 RevisitSubinits,
7233 EnableLifetimeWarnings);
7234
7235 if (ILE->getType()->isArrayType()) {
7236 for (unsigned I = 0, N = ILE->getNumInits(); I != N; ++I)
7237 visitLocalsRetainedByInitializer(Path, ILE->getInit(I), Visit,
7238 RevisitSubinits,
7239 EnableLifetimeWarnings);
7240 return;
7241 }
7242
7243 if (CXXRecordDecl *RD = ILE->getType()->getAsCXXRecordDecl()) {
7244 assert(RD->isAggregate() && "aggregate init on non-aggregate");
7245
7246 // If we lifetime-extend a braced initializer which is initializing an
7247 // aggregate, and that aggregate contains reference members which are
7248 // bound to temporaries, those temporaries are also lifetime-extended.
7249 if (RD->isUnion() && ILE->getInitializedFieldInUnion() &&
7250 ILE->getInitializedFieldInUnion()->getType()->isReferenceType())
7251 visitLocalsRetainedByReferenceBinding(Path, ILE->getInit(0),
7252 RK_ReferenceBinding, Visit,
7253 EnableLifetimeWarnings);
7254 else {
7255 unsigned Index = 0;
7256 for (; Index < RD->getNumBases() && Index < ILE->getNumInits(); ++Index)
7257 visitLocalsRetainedByInitializer(Path, ILE->getInit(Index), Visit,
7258 RevisitSubinits,
7259 EnableLifetimeWarnings);
7260 for (const auto *I : RD->fields()) {
7261 if (Index >= ILE->getNumInits())
7262 break;
7263 if (I->isUnnamedBitfield())
7264 continue;
7265 Expr *SubInit = ILE->getInit(Index);
7266 if (I->getType()->isReferenceType())
7267 visitLocalsRetainedByReferenceBinding(Path, SubInit,
7268 RK_ReferenceBinding, Visit,
7269 EnableLifetimeWarnings);
7270 else
7271 // This might be either aggregate-initialization of a member or
7272 // initialization of a std::initializer_list object. Regardless,
7273 // we should recursively lifetime-extend that initializer.
7274 visitLocalsRetainedByInitializer(Path, SubInit, Visit,
7275 RevisitSubinits,
7276 EnableLifetimeWarnings);
7277 ++Index;
7278 }
7279 }
7280 }
7281 return;
7282 }
7283
7284 // The lifetime of an init-capture is that of the closure object constructed
7285 // by a lambda-expression.
7286 if (auto *LE = dyn_cast<LambdaExpr>(Init)) {
7287 LambdaExpr::capture_iterator CapI = LE->capture_begin();
7288 for (Expr *E : LE->capture_inits()) {
7289 assert(CapI != LE->capture_end());
7290 const LambdaCapture &Cap = *CapI++;
7291 if (!E)
7292 continue;
7293 if (Cap.capturesVariable())
7294 Path.push_back({IndirectLocalPathEntry::LambdaCaptureInit, E, &Cap});
7295 if (E->isGLValue())
7296 visitLocalsRetainedByReferenceBinding(Path, E, RK_ReferenceBinding,
7297 Visit, EnableLifetimeWarnings);
7298 else
7299 visitLocalsRetainedByInitializer(Path, E, Visit, true,
7300 EnableLifetimeWarnings);
7301 if (Cap.capturesVariable())
7302 Path.pop_back();
7303 }
7304 }
7305
7306 // Assume that a copy or move from a temporary references the same objects
7307 // that the temporary does.
7308 if (auto *CCE = dyn_cast<CXXConstructExpr>(Init)) {
7309 if (CCE->getConstructor()->isCopyOrMoveConstructor()) {
7310 if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(CCE->getArg(0))) {
7311 Expr *Arg = MTE->getSubExpr();
7312 Path.push_back({IndirectLocalPathEntry::TemporaryCopy, Arg,
7313 CCE->getConstructor()});
7314 visitLocalsRetainedByInitializer(Path, Arg, Visit, true,
7315 /*EnableLifetimeWarnings*/false);
7316 Path.pop_back();
7317 }
7318 }
7319 }
7320
7321 if (isa<CallExpr>(Init) || isa<CXXConstructExpr>(Init)) {
7322 if (EnableLifetimeWarnings)
7323 handleGslAnnotatedTypes(Path, Init, Visit);
7324 return visitLifetimeBoundArguments(Path, Init, Visit);
7325 }
7326
7327 switch (Init->getStmtClass()) {
7328 case Stmt::UnaryOperatorClass: {
7329 auto *UO = cast<UnaryOperator>(Init);
7330 // If the initializer is the address of a local, we could have a lifetime
7331 // problem.
7332 if (UO->getOpcode() == UO_AddrOf) {
7333 // If this is &rvalue, then it's ill-formed and we have already diagnosed
7334 // it. Don't produce a redundant warning about the lifetime of the
7335 // temporary.
7336 if (isa<MaterializeTemporaryExpr>(UO->getSubExpr()))
7337 return;
7338
7339 Path.push_back({IndirectLocalPathEntry::AddressOf, UO});
7340 visitLocalsRetainedByReferenceBinding(Path, UO->getSubExpr(),
7341 RK_ReferenceBinding, Visit,
7342 EnableLifetimeWarnings);
7343 }
7344 break;
7345 }
7346
7347 case Stmt::BinaryOperatorClass: {
7348 // Handle pointer arithmetic.
7349 auto *BO = cast<BinaryOperator>(Init);
7350 BinaryOperatorKind BOK = BO->getOpcode();
7351 if (!BO->getType()->isPointerType() || (BOK != BO_Add && BOK != BO_Sub))
7352 break;
7353
7354 if (BO->getLHS()->getType()->isPointerType())
7355 visitLocalsRetainedByInitializer(Path, BO->getLHS(), Visit, true,
7356 EnableLifetimeWarnings);
7357 else if (BO->getRHS()->getType()->isPointerType())
7358 visitLocalsRetainedByInitializer(Path, BO->getRHS(), Visit, true,
7359 EnableLifetimeWarnings);
7360 break;
7361 }
7362
7363 case Stmt::ConditionalOperatorClass:
7364 case Stmt::BinaryConditionalOperatorClass: {
7365 auto *C = cast<AbstractConditionalOperator>(Init);
7366 // In C++, we can have a throw-expression operand, which has 'void' type
7367 // and isn't interesting from a lifetime perspective.
7368 if (!C->getTrueExpr()->getType()->isVoidType())
7369 visitLocalsRetainedByInitializer(Path, C->getTrueExpr(), Visit, true,
7370 EnableLifetimeWarnings);
7371 if (!C->getFalseExpr()->getType()->isVoidType())
7372 visitLocalsRetainedByInitializer(Path, C->getFalseExpr(), Visit, true,
7373 EnableLifetimeWarnings);
7374 break;
7375 }
7376
7377 case Stmt::BlockExprClass:
7378 if (cast<BlockExpr>(Init)->getBlockDecl()->hasCaptures()) {
7379 // This is a local block, whose lifetime is that of the function.
7380 Visit(Path, Local(cast<BlockExpr>(Init)), RK_ReferenceBinding);
7381 }
7382 break;
7383
7384 case Stmt::AddrLabelExprClass:
7385 // We want to warn if the address of a label would escape the function.
7386 Visit(Path, Local(cast<AddrLabelExpr>(Init)), RK_ReferenceBinding);
7387 break;
7388
7389 default:
7390 break;
7391 }
7392 }
7393
7394 /// Whether a path to an object supports lifetime extension.
7395 enum PathLifetimeKind {
7396 /// Lifetime-extend along this path.
7397 Extend,
7398 /// We should lifetime-extend, but we don't because (due to technical
7399 /// limitations) we can't. This happens for default member initializers,
7400 /// which we don't clone for every use, so we don't have a unique
7401 /// MaterializeTemporaryExpr to update.
7402 ShouldExtend,
7403 /// Do not lifetime extend along this path.
7404 NoExtend
7405 };
7406
7407 /// Determine whether this is an indirect path to a temporary that we are
7408 /// supposed to lifetime-extend along.
7409 static PathLifetimeKind
shouldLifetimeExtendThroughPath(const IndirectLocalPath & Path)7410 shouldLifetimeExtendThroughPath(const IndirectLocalPath &Path) {
7411 PathLifetimeKind Kind = PathLifetimeKind::Extend;
7412 for (auto Elem : Path) {
7413 if (Elem.Kind == IndirectLocalPathEntry::DefaultInit)
7414 Kind = PathLifetimeKind::ShouldExtend;
7415 else if (Elem.Kind != IndirectLocalPathEntry::LambdaCaptureInit)
7416 return PathLifetimeKind::NoExtend;
7417 }
7418 return Kind;
7419 }
7420
7421 /// Find the range for the first interesting entry in the path at or after I.
nextPathEntryRange(const IndirectLocalPath & Path,unsigned I,Expr * E)7422 static SourceRange nextPathEntryRange(const IndirectLocalPath &Path, unsigned I,
7423 Expr *E) {
7424 for (unsigned N = Path.size(); I != N; ++I) {
7425 switch (Path[I].Kind) {
7426 case IndirectLocalPathEntry::AddressOf:
7427 case IndirectLocalPathEntry::LValToRVal:
7428 case IndirectLocalPathEntry::LifetimeBoundCall:
7429 case IndirectLocalPathEntry::TemporaryCopy:
7430 case IndirectLocalPathEntry::GslReferenceInit:
7431 case IndirectLocalPathEntry::GslPointerInit:
7432 // These exist primarily to mark the path as not permitting or
7433 // supporting lifetime extension.
7434 break;
7435
7436 case IndirectLocalPathEntry::VarInit:
7437 if (cast<VarDecl>(Path[I].D)->isImplicit())
7438 return SourceRange();
7439 LLVM_FALLTHROUGH;
7440 case IndirectLocalPathEntry::DefaultInit:
7441 return Path[I].E->getSourceRange();
7442
7443 case IndirectLocalPathEntry::LambdaCaptureInit:
7444 if (!Path[I].Capture->capturesVariable())
7445 continue;
7446 return Path[I].E->getSourceRange();
7447 }
7448 }
7449 return E->getSourceRange();
7450 }
7451
pathOnlyInitializesGslPointer(IndirectLocalPath & Path)7452 static bool pathOnlyInitializesGslPointer(IndirectLocalPath &Path) {
7453 for (auto It = Path.rbegin(), End = Path.rend(); It != End; ++It) {
7454 if (It->Kind == IndirectLocalPathEntry::VarInit)
7455 continue;
7456 if (It->Kind == IndirectLocalPathEntry::AddressOf)
7457 continue;
7458 return It->Kind == IndirectLocalPathEntry::GslPointerInit ||
7459 It->Kind == IndirectLocalPathEntry::GslReferenceInit;
7460 }
7461 return false;
7462 }
7463
checkInitializerLifetime(const InitializedEntity & Entity,Expr * Init)7464 void Sema::checkInitializerLifetime(const InitializedEntity &Entity,
7465 Expr *Init) {
7466 LifetimeResult LR = getEntityLifetime(&Entity);
7467 LifetimeKind LK = LR.getInt();
7468 const InitializedEntity *ExtendingEntity = LR.getPointer();
7469
7470 // If this entity doesn't have an interesting lifetime, don't bother looking
7471 // for temporaries within its initializer.
7472 if (LK == LK_FullExpression)
7473 return;
7474
7475 auto TemporaryVisitor = [&](IndirectLocalPath &Path, Local L,
7476 ReferenceKind RK) -> bool {
7477 SourceRange DiagRange = nextPathEntryRange(Path, 0, L);
7478 SourceLocation DiagLoc = DiagRange.getBegin();
7479
7480 auto *MTE = dyn_cast<MaterializeTemporaryExpr>(L);
7481
7482 bool IsGslPtrInitWithGslTempOwner = false;
7483 bool IsLocalGslOwner = false;
7484 if (pathOnlyInitializesGslPointer(Path)) {
7485 if (isa<DeclRefExpr>(L)) {
7486 // We do not want to follow the references when returning a pointer originating
7487 // from a local owner to avoid the following false positive:
7488 // int &p = *localUniquePtr;
7489 // someContainer.add(std::move(localUniquePtr));
7490 // return p;
7491 IsLocalGslOwner = isRecordWithAttr<OwnerAttr>(L->getType());
7492 if (pathContainsInit(Path) || !IsLocalGslOwner)
7493 return false;
7494 } else {
7495 IsGslPtrInitWithGslTempOwner = MTE && !MTE->getExtendingDecl() &&
7496 isRecordWithAttr<OwnerAttr>(MTE->getType());
7497 // Skipping a chain of initializing gsl::Pointer annotated objects.
7498 // We are looking only for the final source to find out if it was
7499 // a local or temporary owner or the address of a local variable/param.
7500 if (!IsGslPtrInitWithGslTempOwner)
7501 return true;
7502 }
7503 }
7504
7505 switch (LK) {
7506 case LK_FullExpression:
7507 llvm_unreachable("already handled this");
7508
7509 case LK_Extended: {
7510 if (!MTE) {
7511 // The initialized entity has lifetime beyond the full-expression,
7512 // and the local entity does too, so don't warn.
7513 //
7514 // FIXME: We should consider warning if a static / thread storage
7515 // duration variable retains an automatic storage duration local.
7516 return false;
7517 }
7518
7519 if (IsGslPtrInitWithGslTempOwner && DiagLoc.isValid()) {
7520 Diag(DiagLoc, diag::warn_dangling_lifetime_pointer) << DiagRange;
7521 return false;
7522 }
7523
7524 switch (shouldLifetimeExtendThroughPath(Path)) {
7525 case PathLifetimeKind::Extend:
7526 // Update the storage duration of the materialized temporary.
7527 // FIXME: Rebuild the expression instead of mutating it.
7528 MTE->setExtendingDecl(ExtendingEntity->getDecl(),
7529 ExtendingEntity->allocateManglingNumber());
7530 // Also visit the temporaries lifetime-extended by this initializer.
7531 return true;
7532
7533 case PathLifetimeKind::ShouldExtend:
7534 // We're supposed to lifetime-extend the temporary along this path (per
7535 // the resolution of DR1815), but we don't support that yet.
7536 //
7537 // FIXME: Properly handle this situation. Perhaps the easiest approach
7538 // would be to clone the initializer expression on each use that would
7539 // lifetime extend its temporaries.
7540 Diag(DiagLoc, diag::warn_unsupported_lifetime_extension)
7541 << RK << DiagRange;
7542 break;
7543
7544 case PathLifetimeKind::NoExtend:
7545 // If the path goes through the initialization of a variable or field,
7546 // it can't possibly reach a temporary created in this full-expression.
7547 // We will have already diagnosed any problems with the initializer.
7548 if (pathContainsInit(Path))
7549 return false;
7550
7551 Diag(DiagLoc, diag::warn_dangling_variable)
7552 << RK << !Entity.getParent()
7553 << ExtendingEntity->getDecl()->isImplicit()
7554 << ExtendingEntity->getDecl() << Init->isGLValue() << DiagRange;
7555 break;
7556 }
7557 break;
7558 }
7559
7560 case LK_MemInitializer: {
7561 if (isa<MaterializeTemporaryExpr>(L)) {
7562 // Under C++ DR1696, if a mem-initializer (or a default member
7563 // initializer used by the absence of one) would lifetime-extend a
7564 // temporary, the program is ill-formed.
7565 if (auto *ExtendingDecl =
7566 ExtendingEntity ? ExtendingEntity->getDecl() : nullptr) {
7567 if (IsGslPtrInitWithGslTempOwner) {
7568 Diag(DiagLoc, diag::warn_dangling_lifetime_pointer_member)
7569 << ExtendingDecl << DiagRange;
7570 Diag(ExtendingDecl->getLocation(),
7571 diag::note_ref_or_ptr_member_declared_here)
7572 << true;
7573 return false;
7574 }
7575 bool IsSubobjectMember = ExtendingEntity != &Entity;
7576 Diag(DiagLoc, shouldLifetimeExtendThroughPath(Path) !=
7577 PathLifetimeKind::NoExtend
7578 ? diag::err_dangling_member
7579 : diag::warn_dangling_member)
7580 << ExtendingDecl << IsSubobjectMember << RK << DiagRange;
7581 // Don't bother adding a note pointing to the field if we're inside
7582 // its default member initializer; our primary diagnostic points to
7583 // the same place in that case.
7584 if (Path.empty() ||
7585 Path.back().Kind != IndirectLocalPathEntry::DefaultInit) {
7586 Diag(ExtendingDecl->getLocation(),
7587 diag::note_lifetime_extending_member_declared_here)
7588 << RK << IsSubobjectMember;
7589 }
7590 } else {
7591 // We have a mem-initializer but no particular field within it; this
7592 // is either a base class or a delegating initializer directly
7593 // initializing the base-class from something that doesn't live long
7594 // enough.
7595 //
7596 // FIXME: Warn on this.
7597 return false;
7598 }
7599 } else {
7600 // Paths via a default initializer can only occur during error recovery
7601 // (there's no other way that a default initializer can refer to a
7602 // local). Don't produce a bogus warning on those cases.
7603 if (pathContainsInit(Path))
7604 return false;
7605
7606 // Suppress false positives for code like the one below:
7607 // Ctor(unique_ptr<T> up) : member(*up), member2(move(up)) {}
7608 if (IsLocalGslOwner && pathOnlyInitializesGslPointer(Path))
7609 return false;
7610
7611 auto *DRE = dyn_cast<DeclRefExpr>(L);
7612 auto *VD = DRE ? dyn_cast<VarDecl>(DRE->getDecl()) : nullptr;
7613 if (!VD) {
7614 // A member was initialized to a local block.
7615 // FIXME: Warn on this.
7616 return false;
7617 }
7618
7619 if (auto *Member =
7620 ExtendingEntity ? ExtendingEntity->getDecl() : nullptr) {
7621 bool IsPointer = !Member->getType()->isReferenceType();
7622 Diag(DiagLoc, IsPointer ? diag::warn_init_ptr_member_to_parameter_addr
7623 : diag::warn_bind_ref_member_to_parameter)
7624 << Member << VD << isa<ParmVarDecl>(VD) << DiagRange;
7625 Diag(Member->getLocation(),
7626 diag::note_ref_or_ptr_member_declared_here)
7627 << (unsigned)IsPointer;
7628 }
7629 }
7630 break;
7631 }
7632
7633 case LK_New:
7634 if (isa<MaterializeTemporaryExpr>(L)) {
7635 if (IsGslPtrInitWithGslTempOwner)
7636 Diag(DiagLoc, diag::warn_dangling_lifetime_pointer) << DiagRange;
7637 else
7638 Diag(DiagLoc, RK == RK_ReferenceBinding
7639 ? diag::warn_new_dangling_reference
7640 : diag::warn_new_dangling_initializer_list)
7641 << !Entity.getParent() << DiagRange;
7642 } else {
7643 // We can't determine if the allocation outlives the local declaration.
7644 return false;
7645 }
7646 break;
7647
7648 case LK_Return:
7649 case LK_StmtExprResult:
7650 if (auto *DRE = dyn_cast<DeclRefExpr>(L)) {
7651 // We can't determine if the local variable outlives the statement
7652 // expression.
7653 if (LK == LK_StmtExprResult)
7654 return false;
7655 Diag(DiagLoc, diag::warn_ret_stack_addr_ref)
7656 << Entity.getType()->isReferenceType() << DRE->getDecl()
7657 << isa<ParmVarDecl>(DRE->getDecl()) << DiagRange;
7658 } else if (isa<BlockExpr>(L)) {
7659 Diag(DiagLoc, diag::err_ret_local_block) << DiagRange;
7660 } else if (isa<AddrLabelExpr>(L)) {
7661 // Don't warn when returning a label from a statement expression.
7662 // Leaving the scope doesn't end its lifetime.
7663 if (LK == LK_StmtExprResult)
7664 return false;
7665 Diag(DiagLoc, diag::warn_ret_addr_label) << DiagRange;
7666 } else {
7667 Diag(DiagLoc, diag::warn_ret_local_temp_addr_ref)
7668 << Entity.getType()->isReferenceType() << DiagRange;
7669 }
7670 break;
7671 }
7672
7673 for (unsigned I = 0; I != Path.size(); ++I) {
7674 auto Elem = Path[I];
7675
7676 switch (Elem.Kind) {
7677 case IndirectLocalPathEntry::AddressOf:
7678 case IndirectLocalPathEntry::LValToRVal:
7679 // These exist primarily to mark the path as not permitting or
7680 // supporting lifetime extension.
7681 break;
7682
7683 case IndirectLocalPathEntry::LifetimeBoundCall:
7684 case IndirectLocalPathEntry::TemporaryCopy:
7685 case IndirectLocalPathEntry::GslPointerInit:
7686 case IndirectLocalPathEntry::GslReferenceInit:
7687 // FIXME: Consider adding a note for these.
7688 break;
7689
7690 case IndirectLocalPathEntry::DefaultInit: {
7691 auto *FD = cast<FieldDecl>(Elem.D);
7692 Diag(FD->getLocation(), diag::note_init_with_default_member_initalizer)
7693 << FD << nextPathEntryRange(Path, I + 1, L);
7694 break;
7695 }
7696
7697 case IndirectLocalPathEntry::VarInit: {
7698 const VarDecl *VD = cast<VarDecl>(Elem.D);
7699 Diag(VD->getLocation(), diag::note_local_var_initializer)
7700 << VD->getType()->isReferenceType()
7701 << VD->isImplicit() << VD->getDeclName()
7702 << nextPathEntryRange(Path, I + 1, L);
7703 break;
7704 }
7705
7706 case IndirectLocalPathEntry::LambdaCaptureInit:
7707 if (!Elem.Capture->capturesVariable())
7708 break;
7709 // FIXME: We can't easily tell apart an init-capture from a nested
7710 // capture of an init-capture.
7711 const VarDecl *VD = Elem.Capture->getCapturedVar();
7712 Diag(Elem.Capture->getLocation(), diag::note_lambda_capture_initializer)
7713 << VD << VD->isInitCapture() << Elem.Capture->isExplicit()
7714 << (Elem.Capture->getCaptureKind() == LCK_ByRef) << VD
7715 << nextPathEntryRange(Path, I + 1, L);
7716 break;
7717 }
7718 }
7719
7720 // We didn't lifetime-extend, so don't go any further; we don't need more
7721 // warnings or errors on inner temporaries within this one's initializer.
7722 return false;
7723 };
7724
7725 bool EnableLifetimeWarnings = !getDiagnostics().isIgnored(
7726 diag::warn_dangling_lifetime_pointer, SourceLocation());
7727 llvm::SmallVector<IndirectLocalPathEntry, 8> Path;
7728 if (Init->isGLValue())
7729 visitLocalsRetainedByReferenceBinding(Path, Init, RK_ReferenceBinding,
7730 TemporaryVisitor,
7731 EnableLifetimeWarnings);
7732 else
7733 visitLocalsRetainedByInitializer(Path, Init, TemporaryVisitor, false,
7734 EnableLifetimeWarnings);
7735 }
7736
7737 static void DiagnoseNarrowingInInitList(Sema &S,
7738 const ImplicitConversionSequence &ICS,
7739 QualType PreNarrowingType,
7740 QualType EntityType,
7741 const Expr *PostInit);
7742
7743 /// Provide warnings when std::move is used on construction.
CheckMoveOnConstruction(Sema & S,const Expr * InitExpr,bool IsReturnStmt)7744 static void CheckMoveOnConstruction(Sema &S, const Expr *InitExpr,
7745 bool IsReturnStmt) {
7746 if (!InitExpr)
7747 return;
7748
7749 if (S.inTemplateInstantiation())
7750 return;
7751
7752 QualType DestType = InitExpr->getType();
7753 if (!DestType->isRecordType())
7754 return;
7755
7756 unsigned DiagID = 0;
7757 if (IsReturnStmt) {
7758 const CXXConstructExpr *CCE =
7759 dyn_cast<CXXConstructExpr>(InitExpr->IgnoreParens());
7760 if (!CCE || CCE->getNumArgs() != 1)
7761 return;
7762
7763 if (!CCE->getConstructor()->isCopyOrMoveConstructor())
7764 return;
7765
7766 InitExpr = CCE->getArg(0)->IgnoreImpCasts();
7767 }
7768
7769 // Find the std::move call and get the argument.
7770 const CallExpr *CE = dyn_cast<CallExpr>(InitExpr->IgnoreParens());
7771 if (!CE || !CE->isCallToStdMove())
7772 return;
7773
7774 const Expr *Arg = CE->getArg(0)->IgnoreImplicit();
7775
7776 if (IsReturnStmt) {
7777 const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg->IgnoreParenImpCasts());
7778 if (!DRE || DRE->refersToEnclosingVariableOrCapture())
7779 return;
7780
7781 const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl());
7782 if (!VD || !VD->hasLocalStorage())
7783 return;
7784
7785 // __block variables are not moved implicitly.
7786 if (VD->hasAttr<BlocksAttr>())
7787 return;
7788
7789 QualType SourceType = VD->getType();
7790 if (!SourceType->isRecordType())
7791 return;
7792
7793 if (!S.Context.hasSameUnqualifiedType(DestType, SourceType)) {
7794 return;
7795 }
7796
7797 // If we're returning a function parameter, copy elision
7798 // is not possible.
7799 if (isa<ParmVarDecl>(VD))
7800 DiagID = diag::warn_redundant_move_on_return;
7801 else
7802 DiagID = diag::warn_pessimizing_move_on_return;
7803 } else {
7804 DiagID = diag::warn_pessimizing_move_on_initialization;
7805 const Expr *ArgStripped = Arg->IgnoreImplicit()->IgnoreParens();
7806 if (!ArgStripped->isRValue() || !ArgStripped->getType()->isRecordType())
7807 return;
7808 }
7809
7810 S.Diag(CE->getBeginLoc(), DiagID);
7811
7812 // Get all the locations for a fix-it. Don't emit the fix-it if any location
7813 // is within a macro.
7814 SourceLocation CallBegin = CE->getCallee()->getBeginLoc();
7815 if (CallBegin.isMacroID())
7816 return;
7817 SourceLocation RParen = CE->getRParenLoc();
7818 if (RParen.isMacroID())
7819 return;
7820 SourceLocation LParen;
7821 SourceLocation ArgLoc = Arg->getBeginLoc();
7822
7823 // Special testing for the argument location. Since the fix-it needs the
7824 // location right before the argument, the argument location can be in a
7825 // macro only if it is at the beginning of the macro.
7826 while (ArgLoc.isMacroID() &&
7827 S.getSourceManager().isAtStartOfImmediateMacroExpansion(ArgLoc)) {
7828 ArgLoc = S.getSourceManager().getImmediateExpansionRange(ArgLoc).getBegin();
7829 }
7830
7831 if (LParen.isMacroID())
7832 return;
7833
7834 LParen = ArgLoc.getLocWithOffset(-1);
7835
7836 S.Diag(CE->getBeginLoc(), diag::note_remove_move)
7837 << FixItHint::CreateRemoval(SourceRange(CallBegin, LParen))
7838 << FixItHint::CreateRemoval(SourceRange(RParen, RParen));
7839 }
7840
CheckForNullPointerDereference(Sema & S,const Expr * E)7841 static void CheckForNullPointerDereference(Sema &S, const Expr *E) {
7842 // Check to see if we are dereferencing a null pointer. If so, this is
7843 // undefined behavior, so warn about it. This only handles the pattern
7844 // "*null", which is a very syntactic check.
7845 if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E->IgnoreParenCasts()))
7846 if (UO->getOpcode() == UO_Deref &&
7847 UO->getSubExpr()->IgnoreParenCasts()->
7848 isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull)) {
7849 S.DiagRuntimeBehavior(UO->getOperatorLoc(), UO,
7850 S.PDiag(diag::warn_binding_null_to_reference)
7851 << UO->getSubExpr()->getSourceRange());
7852 }
7853 }
7854
7855 MaterializeTemporaryExpr *
CreateMaterializeTemporaryExpr(QualType T,Expr * Temporary,bool BoundToLvalueReference)7856 Sema::CreateMaterializeTemporaryExpr(QualType T, Expr *Temporary,
7857 bool BoundToLvalueReference) {
7858 auto MTE = new (Context)
7859 MaterializeTemporaryExpr(T, Temporary, BoundToLvalueReference);
7860
7861 // Order an ExprWithCleanups for lifetime marks.
7862 //
7863 // TODO: It'll be good to have a single place to check the access of the
7864 // destructor and generate ExprWithCleanups for various uses. Currently these
7865 // are done in both CreateMaterializeTemporaryExpr and MaybeBindToTemporary,
7866 // but there may be a chance to merge them.
7867 Cleanup.setExprNeedsCleanups(false);
7868 return MTE;
7869 }
7870
TemporaryMaterializationConversion(Expr * E)7871 ExprResult Sema::TemporaryMaterializationConversion(Expr *E) {
7872 // In C++98, we don't want to implicitly create an xvalue.
7873 // FIXME: This means that AST consumers need to deal with "prvalues" that
7874 // denote materialized temporaries. Maybe we should add another ValueKind
7875 // for "xvalue pretending to be a prvalue" for C++98 support.
7876 if (!E->isRValue() || !getLangOpts().CPlusPlus11)
7877 return E;
7878
7879 // C++1z [conv.rval]/1: T shall be a complete type.
7880 // FIXME: Does this ever matter (can we form a prvalue of incomplete type)?
7881 // If so, we should check for a non-abstract class type here too.
7882 QualType T = E->getType();
7883 if (RequireCompleteType(E->getExprLoc(), T, diag::err_incomplete_type))
7884 return ExprError();
7885
7886 return CreateMaterializeTemporaryExpr(E->getType(), E, false);
7887 }
7888
PerformQualificationConversion(Expr * E,QualType Ty,ExprValueKind VK,CheckedConversionKind CCK)7889 ExprResult Sema::PerformQualificationConversion(Expr *E, QualType Ty,
7890 ExprValueKind VK,
7891 CheckedConversionKind CCK) {
7892
7893 CastKind CK = CK_NoOp;
7894
7895 if (VK == VK_RValue) {
7896 auto PointeeTy = Ty->getPointeeType();
7897 auto ExprPointeeTy = E->getType()->getPointeeType();
7898 if (!PointeeTy.isNull() &&
7899 PointeeTy.getAddressSpace() != ExprPointeeTy.getAddressSpace())
7900 CK = CK_AddressSpaceConversion;
7901 } else if (Ty.getAddressSpace() != E->getType().getAddressSpace()) {
7902 CK = CK_AddressSpaceConversion;
7903 }
7904
7905 return ImpCastExprToType(E, Ty, CK, VK, /*BasePath=*/nullptr, CCK);
7906 }
7907
Perform(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Args,QualType * ResultType)7908 ExprResult InitializationSequence::Perform(Sema &S,
7909 const InitializedEntity &Entity,
7910 const InitializationKind &Kind,
7911 MultiExprArg Args,
7912 QualType *ResultType) {
7913 if (Failed()) {
7914 Diagnose(S, Entity, Kind, Args);
7915 return ExprError();
7916 }
7917 if (!ZeroInitializationFixit.empty()) {
7918 unsigned DiagID = diag::err_default_init_const;
7919 if (Decl *D = Entity.getDecl())
7920 if (S.getLangOpts().MSVCCompat && D->hasAttr<SelectAnyAttr>())
7921 DiagID = diag::ext_default_init_const;
7922
7923 // The initialization would have succeeded with this fixit. Since the fixit
7924 // is on the error, we need to build a valid AST in this case, so this isn't
7925 // handled in the Failed() branch above.
7926 QualType DestType = Entity.getType();
7927 S.Diag(Kind.getLocation(), DiagID)
7928 << DestType << (bool)DestType->getAs<RecordType>()
7929 << FixItHint::CreateInsertion(ZeroInitializationFixitLoc,
7930 ZeroInitializationFixit);
7931 }
7932
7933 if (getKind() == DependentSequence) {
7934 // If the declaration is a non-dependent, incomplete array type
7935 // that has an initializer, then its type will be completed once
7936 // the initializer is instantiated.
7937 if (ResultType && !Entity.getType()->isDependentType() &&
7938 Args.size() == 1) {
7939 QualType DeclType = Entity.getType();
7940 if (const IncompleteArrayType *ArrayT
7941 = S.Context.getAsIncompleteArrayType(DeclType)) {
7942 // FIXME: We don't currently have the ability to accurately
7943 // compute the length of an initializer list without
7944 // performing full type-checking of the initializer list
7945 // (since we have to determine where braces are implicitly
7946 // introduced and such). So, we fall back to making the array
7947 // type a dependently-sized array type with no specified
7948 // bound.
7949 if (isa<InitListExpr>((Expr *)Args[0])) {
7950 SourceRange Brackets;
7951
7952 // Scavange the location of the brackets from the entity, if we can.
7953 if (auto *DD = dyn_cast_or_null<DeclaratorDecl>(Entity.getDecl())) {
7954 if (TypeSourceInfo *TInfo = DD->getTypeSourceInfo()) {
7955 TypeLoc TL = TInfo->getTypeLoc();
7956 if (IncompleteArrayTypeLoc ArrayLoc =
7957 TL.getAs<IncompleteArrayTypeLoc>())
7958 Brackets = ArrayLoc.getBracketsRange();
7959 }
7960 }
7961
7962 *ResultType
7963 = S.Context.getDependentSizedArrayType(ArrayT->getElementType(),
7964 /*NumElts=*/nullptr,
7965 ArrayT->getSizeModifier(),
7966 ArrayT->getIndexTypeCVRQualifiers(),
7967 Brackets);
7968 }
7969
7970 }
7971 }
7972 if (Kind.getKind() == InitializationKind::IK_Direct &&
7973 !Kind.isExplicitCast()) {
7974 // Rebuild the ParenListExpr.
7975 SourceRange ParenRange = Kind.getParenOrBraceRange();
7976 return S.ActOnParenListExpr(ParenRange.getBegin(), ParenRange.getEnd(),
7977 Args);
7978 }
7979 assert(Kind.getKind() == InitializationKind::IK_Copy ||
7980 Kind.isExplicitCast() ||
7981 Kind.getKind() == InitializationKind::IK_DirectList);
7982 return ExprResult(Args[0]);
7983 }
7984
7985 // No steps means no initialization.
7986 if (Steps.empty())
7987 return ExprResult((Expr *)nullptr);
7988
7989 if (S.getLangOpts().CPlusPlus11 && Entity.getType()->isReferenceType() &&
7990 Args.size() == 1 && isa<InitListExpr>(Args[0]) &&
7991 !Entity.isParamOrTemplateParamKind()) {
7992 // Produce a C++98 compatibility warning if we are initializing a reference
7993 // from an initializer list. For parameters, we produce a better warning
7994 // elsewhere.
7995 Expr *Init = Args[0];
7996 S.Diag(Init->getBeginLoc(), diag::warn_cxx98_compat_reference_list_init)
7997 << Init->getSourceRange();
7998 }
7999
8000 // OpenCL v2.0 s6.13.11.1. atomic variables can be initialized in global scope
8001 QualType ETy = Entity.getType();
8002 bool HasGlobalAS = ETy.hasAddressSpace() &&
8003 ETy.getAddressSpace() == LangAS::opencl_global;
8004
8005 if (S.getLangOpts().OpenCLVersion >= 200 &&
8006 ETy->isAtomicType() && !HasGlobalAS &&
8007 Entity.getKind() == InitializedEntity::EK_Variable && Args.size() > 0) {
8008 S.Diag(Args[0]->getBeginLoc(), diag::err_opencl_atomic_init)
8009 << 1
8010 << SourceRange(Entity.getDecl()->getBeginLoc(), Args[0]->getEndLoc());
8011 return ExprError();
8012 }
8013
8014 QualType DestType = Entity.getType().getNonReferenceType();
8015 // FIXME: Ugly hack around the fact that Entity.getType() is not
8016 // the same as Entity.getDecl()->getType() in cases involving type merging,
8017 // and we want latter when it makes sense.
8018 if (ResultType)
8019 *ResultType = Entity.getDecl() ? Entity.getDecl()->getType() :
8020 Entity.getType();
8021
8022 ExprResult CurInit((Expr *)nullptr);
8023 SmallVector<Expr*, 4> ArrayLoopCommonExprs;
8024
8025 // For initialization steps that start with a single initializer,
8026 // grab the only argument out the Args and place it into the "current"
8027 // initializer.
8028 switch (Steps.front().Kind) {
8029 case SK_ResolveAddressOfOverloadedFunction:
8030 case SK_CastDerivedToBaseRValue:
8031 case SK_CastDerivedToBaseXValue:
8032 case SK_CastDerivedToBaseLValue:
8033 case SK_BindReference:
8034 case SK_BindReferenceToTemporary:
8035 case SK_FinalCopy:
8036 case SK_ExtraneousCopyToTemporary:
8037 case SK_UserConversion:
8038 case SK_QualificationConversionLValue:
8039 case SK_QualificationConversionXValue:
8040 case SK_QualificationConversionRValue:
8041 case SK_AtomicConversion:
8042 case SK_ConversionSequence:
8043 case SK_ConversionSequenceNoNarrowing:
8044 case SK_ListInitialization:
8045 case SK_UnwrapInitList:
8046 case SK_RewrapInitList:
8047 case SK_CAssignment:
8048 case SK_StringInit:
8049 case SK_ObjCObjectConversion:
8050 case SK_ArrayLoopIndex:
8051 case SK_ArrayLoopInit:
8052 case SK_ArrayInit:
8053 case SK_GNUArrayInit:
8054 case SK_ParenthesizedArrayInit:
8055 case SK_PassByIndirectCopyRestore:
8056 case SK_PassByIndirectRestore:
8057 case SK_ProduceObjCObject:
8058 case SK_StdInitializerList:
8059 case SK_OCLSamplerInit:
8060 case SK_OCLZeroOpaqueType: {
8061 assert(Args.size() == 1);
8062 CurInit = Args[0];
8063 if (!CurInit.get()) return ExprError();
8064 break;
8065 }
8066
8067 case SK_ConstructorInitialization:
8068 case SK_ConstructorInitializationFromList:
8069 case SK_StdInitializerListConstructorCall:
8070 case SK_ZeroInitialization:
8071 break;
8072 }
8073
8074 // Promote from an unevaluated context to an unevaluated list context in
8075 // C++11 list-initialization; we need to instantiate entities usable in
8076 // constant expressions here in order to perform narrowing checks =(
8077 EnterExpressionEvaluationContext Evaluated(
8078 S, EnterExpressionEvaluationContext::InitList,
8079 CurInit.get() && isa<InitListExpr>(CurInit.get()));
8080
8081 // C++ [class.abstract]p2:
8082 // no objects of an abstract class can be created except as subobjects
8083 // of a class derived from it
8084 auto checkAbstractType = [&](QualType T) -> bool {
8085 if (Entity.getKind() == InitializedEntity::EK_Base ||
8086 Entity.getKind() == InitializedEntity::EK_Delegating)
8087 return false;
8088 return S.RequireNonAbstractType(Kind.getLocation(), T,
8089 diag::err_allocation_of_abstract_type);
8090 };
8091
8092 // Walk through the computed steps for the initialization sequence,
8093 // performing the specified conversions along the way.
8094 bool ConstructorInitRequiresZeroInit = false;
8095 for (step_iterator Step = step_begin(), StepEnd = step_end();
8096 Step != StepEnd; ++Step) {
8097 if (CurInit.isInvalid())
8098 return ExprError();
8099
8100 QualType SourceType = CurInit.get() ? CurInit.get()->getType() : QualType();
8101
8102 switch (Step->Kind) {
8103 case SK_ResolveAddressOfOverloadedFunction:
8104 // Overload resolution determined which function invoke; update the
8105 // initializer to reflect that choice.
8106 S.CheckAddressOfMemberAccess(CurInit.get(), Step->Function.FoundDecl);
8107 if (S.DiagnoseUseOfDecl(Step->Function.FoundDecl, Kind.getLocation()))
8108 return ExprError();
8109 CurInit = S.FixOverloadedFunctionReference(CurInit,
8110 Step->Function.FoundDecl,
8111 Step->Function.Function);
8112 break;
8113
8114 case SK_CastDerivedToBaseRValue:
8115 case SK_CastDerivedToBaseXValue:
8116 case SK_CastDerivedToBaseLValue: {
8117 // We have a derived-to-base cast that produces either an rvalue or an
8118 // lvalue. Perform that cast.
8119
8120 CXXCastPath BasePath;
8121
8122 // Casts to inaccessible base classes are allowed with C-style casts.
8123 bool IgnoreBaseAccess = Kind.isCStyleOrFunctionalCast();
8124 if (S.CheckDerivedToBaseConversion(
8125 SourceType, Step->Type, CurInit.get()->getBeginLoc(),
8126 CurInit.get()->getSourceRange(), &BasePath, IgnoreBaseAccess))
8127 return ExprError();
8128
8129 ExprValueKind VK =
8130 Step->Kind == SK_CastDerivedToBaseLValue ?
8131 VK_LValue :
8132 (Step->Kind == SK_CastDerivedToBaseXValue ?
8133 VK_XValue :
8134 VK_RValue);
8135 CurInit = ImplicitCastExpr::Create(S.Context, Step->Type,
8136 CK_DerivedToBase, CurInit.get(),
8137 &BasePath, VK, FPOptionsOverride());
8138 break;
8139 }
8140
8141 case SK_BindReference:
8142 // Reference binding does not have any corresponding ASTs.
8143
8144 // Check exception specifications
8145 if (S.CheckExceptionSpecCompatibility(CurInit.get(), DestType))
8146 return ExprError();
8147
8148 // We don't check for e.g. function pointers here, since address
8149 // availability checks should only occur when the function first decays
8150 // into a pointer or reference.
8151 if (CurInit.get()->getType()->isFunctionProtoType()) {
8152 if (auto *DRE = dyn_cast<DeclRefExpr>(CurInit.get()->IgnoreParens())) {
8153 if (auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl())) {
8154 if (!S.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true,
8155 DRE->getBeginLoc()))
8156 return ExprError();
8157 }
8158 }
8159 }
8160
8161 CheckForNullPointerDereference(S, CurInit.get());
8162 break;
8163
8164 case SK_BindReferenceToTemporary: {
8165 // Make sure the "temporary" is actually an rvalue.
8166 assert(CurInit.get()->isRValue() && "not a temporary");
8167
8168 // Check exception specifications
8169 if (S.CheckExceptionSpecCompatibility(CurInit.get(), DestType))
8170 return ExprError();
8171
8172 // Materialize the temporary into memory.
8173 MaterializeTemporaryExpr *MTE = S.CreateMaterializeTemporaryExpr(
8174 Step->Type, CurInit.get(), Entity.getType()->isLValueReferenceType());
8175 CurInit = MTE;
8176
8177 // If we're extending this temporary to automatic storage duration -- we
8178 // need to register its cleanup during the full-expression's cleanups.
8179 if (MTE->getStorageDuration() == SD_Automatic &&
8180 MTE->getType().isDestructedType())
8181 S.Cleanup.setExprNeedsCleanups(true);
8182 break;
8183 }
8184
8185 case SK_FinalCopy:
8186 if (checkAbstractType(Step->Type))
8187 return ExprError();
8188
8189 // If the overall initialization is initializing a temporary, we already
8190 // bound our argument if it was necessary to do so. If not (if we're
8191 // ultimately initializing a non-temporary), our argument needs to be
8192 // bound since it's initializing a function parameter.
8193 // FIXME: This is a mess. Rationalize temporary destruction.
8194 if (!shouldBindAsTemporary(Entity))
8195 CurInit = S.MaybeBindToTemporary(CurInit.get());
8196 CurInit = CopyObject(S, Step->Type, Entity, CurInit,
8197 /*IsExtraneousCopy=*/false);
8198 break;
8199
8200 case SK_ExtraneousCopyToTemporary:
8201 CurInit = CopyObject(S, Step->Type, Entity, CurInit,
8202 /*IsExtraneousCopy=*/true);
8203 break;
8204
8205 case SK_UserConversion: {
8206 // We have a user-defined conversion that invokes either a constructor
8207 // or a conversion function.
8208 CastKind CastKind;
8209 FunctionDecl *Fn = Step->Function.Function;
8210 DeclAccessPair FoundFn = Step->Function.FoundDecl;
8211 bool HadMultipleCandidates = Step->Function.HadMultipleCandidates;
8212 bool CreatedObject = false;
8213 if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Fn)) {
8214 // Build a call to the selected constructor.
8215 SmallVector<Expr*, 8> ConstructorArgs;
8216 SourceLocation Loc = CurInit.get()->getBeginLoc();
8217
8218 // Determine the arguments required to actually perform the constructor
8219 // call.
8220 Expr *Arg = CurInit.get();
8221 if (S.CompleteConstructorCall(Constructor,
8222 MultiExprArg(&Arg, 1),
8223 Loc, ConstructorArgs))
8224 return ExprError();
8225
8226 // Build an expression that constructs a temporary.
8227 CurInit = S.BuildCXXConstructExpr(Loc, Step->Type,
8228 FoundFn, Constructor,
8229 ConstructorArgs,
8230 HadMultipleCandidates,
8231 /*ListInit*/ false,
8232 /*StdInitListInit*/ false,
8233 /*ZeroInit*/ false,
8234 CXXConstructExpr::CK_Complete,
8235 SourceRange());
8236 if (CurInit.isInvalid())
8237 return ExprError();
8238
8239 S.CheckConstructorAccess(Kind.getLocation(), Constructor, FoundFn,
8240 Entity);
8241 if (S.DiagnoseUseOfDecl(FoundFn, Kind.getLocation()))
8242 return ExprError();
8243
8244 CastKind = CK_ConstructorConversion;
8245 CreatedObject = true;
8246 } else {
8247 // Build a call to the conversion function.
8248 CXXConversionDecl *Conversion = cast<CXXConversionDecl>(Fn);
8249 S.CheckMemberOperatorAccess(Kind.getLocation(), CurInit.get(), nullptr,
8250 FoundFn);
8251 if (S.DiagnoseUseOfDecl(FoundFn, Kind.getLocation()))
8252 return ExprError();
8253
8254 CurInit = S.BuildCXXMemberCallExpr(CurInit.get(), FoundFn, Conversion,
8255 HadMultipleCandidates);
8256 if (CurInit.isInvalid())
8257 return ExprError();
8258
8259 CastKind = CK_UserDefinedConversion;
8260 CreatedObject = Conversion->getReturnType()->isRecordType();
8261 }
8262
8263 if (CreatedObject && checkAbstractType(CurInit.get()->getType()))
8264 return ExprError();
8265
8266 CurInit = ImplicitCastExpr::Create(
8267 S.Context, CurInit.get()->getType(), CastKind, CurInit.get(), nullptr,
8268 CurInit.get()->getValueKind(), S.CurFPFeatureOverrides());
8269
8270 if (shouldBindAsTemporary(Entity))
8271 // The overall entity is temporary, so this expression should be
8272 // destroyed at the end of its full-expression.
8273 CurInit = S.MaybeBindToTemporary(CurInit.getAs<Expr>());
8274 else if (CreatedObject && shouldDestroyEntity(Entity)) {
8275 // The object outlasts the full-expression, but we need to prepare for
8276 // a destructor being run on it.
8277 // FIXME: It makes no sense to do this here. This should happen
8278 // regardless of how we initialized the entity.
8279 QualType T = CurInit.get()->getType();
8280 if (const RecordType *Record = T->getAs<RecordType>()) {
8281 CXXDestructorDecl *Destructor
8282 = S.LookupDestructor(cast<CXXRecordDecl>(Record->getDecl()));
8283 S.CheckDestructorAccess(CurInit.get()->getBeginLoc(), Destructor,
8284 S.PDiag(diag::err_access_dtor_temp) << T);
8285 S.MarkFunctionReferenced(CurInit.get()->getBeginLoc(), Destructor);
8286 if (S.DiagnoseUseOfDecl(Destructor, CurInit.get()->getBeginLoc()))
8287 return ExprError();
8288 }
8289 }
8290 break;
8291 }
8292
8293 case SK_QualificationConversionLValue:
8294 case SK_QualificationConversionXValue:
8295 case SK_QualificationConversionRValue: {
8296 // Perform a qualification conversion; these can never go wrong.
8297 ExprValueKind VK =
8298 Step->Kind == SK_QualificationConversionLValue
8299 ? VK_LValue
8300 : (Step->Kind == SK_QualificationConversionXValue ? VK_XValue
8301 : VK_RValue);
8302 CurInit = S.PerformQualificationConversion(CurInit.get(), Step->Type, VK);
8303 break;
8304 }
8305
8306 case SK_AtomicConversion: {
8307 assert(CurInit.get()->isRValue() && "cannot convert glvalue to atomic");
8308 CurInit = S.ImpCastExprToType(CurInit.get(), Step->Type,
8309 CK_NonAtomicToAtomic, VK_RValue);
8310 break;
8311 }
8312
8313 case SK_ConversionSequence:
8314 case SK_ConversionSequenceNoNarrowing: {
8315 if (const auto *FromPtrType =
8316 CurInit.get()->getType()->getAs<PointerType>()) {
8317 if (const auto *ToPtrType = Step->Type->getAs<PointerType>()) {
8318 if (FromPtrType->getPointeeType()->hasAttr(attr::NoDeref) &&
8319 !ToPtrType->getPointeeType()->hasAttr(attr::NoDeref)) {
8320 // Do not check static casts here because they are checked earlier
8321 // in Sema::ActOnCXXNamedCast()
8322 if (!Kind.isStaticCast()) {
8323 S.Diag(CurInit.get()->getExprLoc(),
8324 diag::warn_noderef_to_dereferenceable_pointer)
8325 << CurInit.get()->getSourceRange();
8326 }
8327 }
8328 }
8329 }
8330
8331 Sema::CheckedConversionKind CCK
8332 = Kind.isCStyleCast()? Sema::CCK_CStyleCast
8333 : Kind.isFunctionalCast()? Sema::CCK_FunctionalCast
8334 : Kind.isExplicitCast()? Sema::CCK_OtherCast
8335 : Sema::CCK_ImplicitConversion;
8336 ExprResult CurInitExprRes =
8337 S.PerformImplicitConversion(CurInit.get(), Step->Type, *Step->ICS,
8338 getAssignmentAction(Entity), CCK);
8339 if (CurInitExprRes.isInvalid())
8340 return ExprError();
8341
8342 S.DiscardMisalignedMemberAddress(Step->Type.getTypePtr(), CurInit.get());
8343
8344 CurInit = CurInitExprRes;
8345
8346 if (Step->Kind == SK_ConversionSequenceNoNarrowing &&
8347 S.getLangOpts().CPlusPlus)
8348 DiagnoseNarrowingInInitList(S, *Step->ICS, SourceType, Entity.getType(),
8349 CurInit.get());
8350
8351 break;
8352 }
8353
8354 case SK_ListInitialization: {
8355 if (checkAbstractType(Step->Type))
8356 return ExprError();
8357
8358 InitListExpr *InitList = cast<InitListExpr>(CurInit.get());
8359 // If we're not initializing the top-level entity, we need to create an
8360 // InitializeTemporary entity for our target type.
8361 QualType Ty = Step->Type;
8362 bool IsTemporary = !S.Context.hasSameType(Entity.getType(), Ty);
8363 InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(Ty);
8364 InitializedEntity InitEntity = IsTemporary ? TempEntity : Entity;
8365 InitListChecker PerformInitList(S, InitEntity,
8366 InitList, Ty, /*VerifyOnly=*/false,
8367 /*TreatUnavailableAsInvalid=*/false);
8368 if (PerformInitList.HadError())
8369 return ExprError();
8370
8371 // Hack: We must update *ResultType if available in order to set the
8372 // bounds of arrays, e.g. in 'int ar[] = {1, 2, 3};'.
8373 // Worst case: 'const int (&arref)[] = {1, 2, 3};'.
8374 if (ResultType &&
8375 ResultType->getNonReferenceType()->isIncompleteArrayType()) {
8376 if ((*ResultType)->isRValueReferenceType())
8377 Ty = S.Context.getRValueReferenceType(Ty);
8378 else if ((*ResultType)->isLValueReferenceType())
8379 Ty = S.Context.getLValueReferenceType(Ty,
8380 (*ResultType)->castAs<LValueReferenceType>()->isSpelledAsLValue());
8381 *ResultType = Ty;
8382 }
8383
8384 InitListExpr *StructuredInitList =
8385 PerformInitList.getFullyStructuredList();
8386 CurInit.get();
8387 CurInit = shouldBindAsTemporary(InitEntity)
8388 ? S.MaybeBindToTemporary(StructuredInitList)
8389 : StructuredInitList;
8390 break;
8391 }
8392
8393 case SK_ConstructorInitializationFromList: {
8394 if (checkAbstractType(Step->Type))
8395 return ExprError();
8396
8397 // When an initializer list is passed for a parameter of type "reference
8398 // to object", we don't get an EK_Temporary entity, but instead an
8399 // EK_Parameter entity with reference type.
8400 // FIXME: This is a hack. What we really should do is create a user
8401 // conversion step for this case, but this makes it considerably more
8402 // complicated. For now, this will do.
8403 InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(
8404 Entity.getType().getNonReferenceType());
8405 bool UseTemporary = Entity.getType()->isReferenceType();
8406 assert(Args.size() == 1 && "expected a single argument for list init");
8407 InitListExpr *InitList = cast<InitListExpr>(Args[0]);
8408 S.Diag(InitList->getExprLoc(), diag::warn_cxx98_compat_ctor_list_init)
8409 << InitList->getSourceRange();
8410 MultiExprArg Arg(InitList->getInits(), InitList->getNumInits());
8411 CurInit = PerformConstructorInitialization(S, UseTemporary ? TempEntity :
8412 Entity,
8413 Kind, Arg, *Step,
8414 ConstructorInitRequiresZeroInit,
8415 /*IsListInitialization*/true,
8416 /*IsStdInitListInit*/false,
8417 InitList->getLBraceLoc(),
8418 InitList->getRBraceLoc());
8419 break;
8420 }
8421
8422 case SK_UnwrapInitList:
8423 CurInit = cast<InitListExpr>(CurInit.get())->getInit(0);
8424 break;
8425
8426 case SK_RewrapInitList: {
8427 Expr *E = CurInit.get();
8428 InitListExpr *Syntactic = Step->WrappingSyntacticList;
8429 InitListExpr *ILE = new (S.Context) InitListExpr(S.Context,
8430 Syntactic->getLBraceLoc(), E, Syntactic->getRBraceLoc());
8431 ILE->setSyntacticForm(Syntactic);
8432 ILE->setType(E->getType());
8433 ILE->setValueKind(E->getValueKind());
8434 CurInit = ILE;
8435 break;
8436 }
8437
8438 case SK_ConstructorInitialization:
8439 case SK_StdInitializerListConstructorCall: {
8440 if (checkAbstractType(Step->Type))
8441 return ExprError();
8442
8443 // When an initializer list is passed for a parameter of type "reference
8444 // to object", we don't get an EK_Temporary entity, but instead an
8445 // EK_Parameter entity with reference type.
8446 // FIXME: This is a hack. What we really should do is create a user
8447 // conversion step for this case, but this makes it considerably more
8448 // complicated. For now, this will do.
8449 InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(
8450 Entity.getType().getNonReferenceType());
8451 bool UseTemporary = Entity.getType()->isReferenceType();
8452 bool IsStdInitListInit =
8453 Step->Kind == SK_StdInitializerListConstructorCall;
8454 Expr *Source = CurInit.get();
8455 SourceRange Range = Kind.hasParenOrBraceRange()
8456 ? Kind.getParenOrBraceRange()
8457 : SourceRange();
8458 CurInit = PerformConstructorInitialization(
8459 S, UseTemporary ? TempEntity : Entity, Kind,
8460 Source ? MultiExprArg(Source) : Args, *Step,
8461 ConstructorInitRequiresZeroInit,
8462 /*IsListInitialization*/ IsStdInitListInit,
8463 /*IsStdInitListInitialization*/ IsStdInitListInit,
8464 /*LBraceLoc*/ Range.getBegin(),
8465 /*RBraceLoc*/ Range.getEnd());
8466 break;
8467 }
8468
8469 case SK_ZeroInitialization: {
8470 step_iterator NextStep = Step;
8471 ++NextStep;
8472 if (NextStep != StepEnd &&
8473 (NextStep->Kind == SK_ConstructorInitialization ||
8474 NextStep->Kind == SK_ConstructorInitializationFromList)) {
8475 // The need for zero-initialization is recorded directly into
8476 // the call to the object's constructor within the next step.
8477 ConstructorInitRequiresZeroInit = true;
8478 } else if (Kind.getKind() == InitializationKind::IK_Value &&
8479 S.getLangOpts().CPlusPlus &&
8480 !Kind.isImplicitValueInit()) {
8481 TypeSourceInfo *TSInfo = Entity.getTypeSourceInfo();
8482 if (!TSInfo)
8483 TSInfo = S.Context.getTrivialTypeSourceInfo(Step->Type,
8484 Kind.getRange().getBegin());
8485
8486 CurInit = new (S.Context) CXXScalarValueInitExpr(
8487 Entity.getType().getNonLValueExprType(S.Context), TSInfo,
8488 Kind.getRange().getEnd());
8489 } else {
8490 CurInit = new (S.Context) ImplicitValueInitExpr(Step->Type);
8491 }
8492 break;
8493 }
8494
8495 case SK_CAssignment: {
8496 QualType SourceType = CurInit.get()->getType();
8497
8498 // Save off the initial CurInit in case we need to emit a diagnostic
8499 ExprResult InitialCurInit = CurInit;
8500 ExprResult Result = CurInit;
8501 Sema::AssignConvertType ConvTy =
8502 S.CheckSingleAssignmentConstraints(Step->Type, Result, true,
8503 Entity.getKind() == InitializedEntity::EK_Parameter_CF_Audited);
8504 if (Result.isInvalid())
8505 return ExprError();
8506 CurInit = Result;
8507
8508 // If this is a call, allow conversion to a transparent union.
8509 ExprResult CurInitExprRes = CurInit;
8510 if (ConvTy != Sema::Compatible &&
8511 Entity.isParameterKind() &&
8512 S.CheckTransparentUnionArgumentConstraints(Step->Type, CurInitExprRes)
8513 == Sema::Compatible)
8514 ConvTy = Sema::Compatible;
8515 if (CurInitExprRes.isInvalid())
8516 return ExprError();
8517 CurInit = CurInitExprRes;
8518
8519 bool Complained;
8520 if (S.DiagnoseAssignmentResult(ConvTy, Kind.getLocation(),
8521 Step->Type, SourceType,
8522 InitialCurInit.get(),
8523 getAssignmentAction(Entity, true),
8524 &Complained)) {
8525 PrintInitLocationNote(S, Entity);
8526 return ExprError();
8527 } else if (Complained)
8528 PrintInitLocationNote(S, Entity);
8529 break;
8530 }
8531
8532 case SK_StringInit: {
8533 QualType Ty = Step->Type;
8534 bool UpdateType = ResultType && Entity.getType()->isIncompleteArrayType();
8535 CheckStringInit(CurInit.get(), UpdateType ? *ResultType : Ty,
8536 S.Context.getAsArrayType(Ty), S);
8537 break;
8538 }
8539
8540 case SK_ObjCObjectConversion:
8541 CurInit = S.ImpCastExprToType(CurInit.get(), Step->Type,
8542 CK_ObjCObjectLValueCast,
8543 CurInit.get()->getValueKind());
8544 break;
8545
8546 case SK_ArrayLoopIndex: {
8547 Expr *Cur = CurInit.get();
8548 Expr *BaseExpr = new (S.Context)
8549 OpaqueValueExpr(Cur->getExprLoc(), Cur->getType(),
8550 Cur->getValueKind(), Cur->getObjectKind(), Cur);
8551 Expr *IndexExpr =
8552 new (S.Context) ArrayInitIndexExpr(S.Context.getSizeType());
8553 CurInit = S.CreateBuiltinArraySubscriptExpr(
8554 BaseExpr, Kind.getLocation(), IndexExpr, Kind.getLocation());
8555 ArrayLoopCommonExprs.push_back(BaseExpr);
8556 break;
8557 }
8558
8559 case SK_ArrayLoopInit: {
8560 assert(!ArrayLoopCommonExprs.empty() &&
8561 "mismatched SK_ArrayLoopIndex and SK_ArrayLoopInit");
8562 Expr *Common = ArrayLoopCommonExprs.pop_back_val();
8563 CurInit = new (S.Context) ArrayInitLoopExpr(Step->Type, Common,
8564 CurInit.get());
8565 break;
8566 }
8567
8568 case SK_GNUArrayInit:
8569 // Okay: we checked everything before creating this step. Note that
8570 // this is a GNU extension.
8571 S.Diag(Kind.getLocation(), diag::ext_array_init_copy)
8572 << Step->Type << CurInit.get()->getType()
8573 << CurInit.get()->getSourceRange();
8574 updateGNUCompoundLiteralRValue(CurInit.get());
8575 LLVM_FALLTHROUGH;
8576 case SK_ArrayInit:
8577 // If the destination type is an incomplete array type, update the
8578 // type accordingly.
8579 if (ResultType) {
8580 if (const IncompleteArrayType *IncompleteDest
8581 = S.Context.getAsIncompleteArrayType(Step->Type)) {
8582 if (const ConstantArrayType *ConstantSource
8583 = S.Context.getAsConstantArrayType(CurInit.get()->getType())) {
8584 *ResultType = S.Context.getConstantArrayType(
8585 IncompleteDest->getElementType(),
8586 ConstantSource->getSize(),
8587 ConstantSource->getSizeExpr(),
8588 ArrayType::Normal, 0);
8589 }
8590 }
8591 }
8592 break;
8593
8594 case SK_ParenthesizedArrayInit:
8595 // Okay: we checked everything before creating this step. Note that
8596 // this is a GNU extension.
8597 S.Diag(Kind.getLocation(), diag::ext_array_init_parens)
8598 << CurInit.get()->getSourceRange();
8599 break;
8600
8601 case SK_PassByIndirectCopyRestore:
8602 case SK_PassByIndirectRestore:
8603 checkIndirectCopyRestoreSource(S, CurInit.get());
8604 CurInit = new (S.Context) ObjCIndirectCopyRestoreExpr(
8605 CurInit.get(), Step->Type,
8606 Step->Kind == SK_PassByIndirectCopyRestore);
8607 break;
8608
8609 case SK_ProduceObjCObject:
8610 CurInit = ImplicitCastExpr::Create(
8611 S.Context, Step->Type, CK_ARCProduceObject, CurInit.get(), nullptr,
8612 VK_RValue, FPOptionsOverride());
8613 break;
8614
8615 case SK_StdInitializerList: {
8616 S.Diag(CurInit.get()->getExprLoc(),
8617 diag::warn_cxx98_compat_initializer_list_init)
8618 << CurInit.get()->getSourceRange();
8619
8620 // Materialize the temporary into memory.
8621 MaterializeTemporaryExpr *MTE = S.CreateMaterializeTemporaryExpr(
8622 CurInit.get()->getType(), CurInit.get(),
8623 /*BoundToLvalueReference=*/false);
8624
8625 // Wrap it in a construction of a std::initializer_list<T>.
8626 CurInit = new (S.Context) CXXStdInitializerListExpr(Step->Type, MTE);
8627
8628 // Bind the result, in case the library has given initializer_list a
8629 // non-trivial destructor.
8630 if (shouldBindAsTemporary(Entity))
8631 CurInit = S.MaybeBindToTemporary(CurInit.get());
8632 break;
8633 }
8634
8635 case SK_OCLSamplerInit: {
8636 // Sampler initialization have 5 cases:
8637 // 1. function argument passing
8638 // 1a. argument is a file-scope variable
8639 // 1b. argument is a function-scope variable
8640 // 1c. argument is one of caller function's parameters
8641 // 2. variable initialization
8642 // 2a. initializing a file-scope variable
8643 // 2b. initializing a function-scope variable
8644 //
8645 // For file-scope variables, since they cannot be initialized by function
8646 // call of __translate_sampler_initializer in LLVM IR, their references
8647 // need to be replaced by a cast from their literal initializers to
8648 // sampler type. Since sampler variables can only be used in function
8649 // calls as arguments, we only need to replace them when handling the
8650 // argument passing.
8651 assert(Step->Type->isSamplerT() &&
8652 "Sampler initialization on non-sampler type.");
8653 Expr *Init = CurInit.get()->IgnoreParens();
8654 QualType SourceType = Init->getType();
8655 // Case 1
8656 if (Entity.isParameterKind()) {
8657 if (!SourceType->isSamplerT() && !SourceType->isIntegerType()) {
8658 S.Diag(Kind.getLocation(), diag::err_sampler_argument_required)
8659 << SourceType;
8660 break;
8661 } else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Init)) {
8662 auto Var = cast<VarDecl>(DRE->getDecl());
8663 // Case 1b and 1c
8664 // No cast from integer to sampler is needed.
8665 if (!Var->hasGlobalStorage()) {
8666 CurInit = ImplicitCastExpr::Create(
8667 S.Context, Step->Type, CK_LValueToRValue, Init,
8668 /*BasePath=*/nullptr, VK_RValue, FPOptionsOverride());
8669 break;
8670 }
8671 // Case 1a
8672 // For function call with a file-scope sampler variable as argument,
8673 // get the integer literal.
8674 // Do not diagnose if the file-scope variable does not have initializer
8675 // since this has already been diagnosed when parsing the variable
8676 // declaration.
8677 if (!Var->getInit() || !isa<ImplicitCastExpr>(Var->getInit()))
8678 break;
8679 Init = cast<ImplicitCastExpr>(const_cast<Expr*>(
8680 Var->getInit()))->getSubExpr();
8681 SourceType = Init->getType();
8682 }
8683 } else {
8684 // Case 2
8685 // Check initializer is 32 bit integer constant.
8686 // If the initializer is taken from global variable, do not diagnose since
8687 // this has already been done when parsing the variable declaration.
8688 if (!Init->isConstantInitializer(S.Context, false))
8689 break;
8690
8691 if (!SourceType->isIntegerType() ||
8692 32 != S.Context.getIntWidth(SourceType)) {
8693 S.Diag(Kind.getLocation(), diag::err_sampler_initializer_not_integer)
8694 << SourceType;
8695 break;
8696 }
8697
8698 Expr::EvalResult EVResult;
8699 Init->EvaluateAsInt(EVResult, S.Context);
8700 llvm::APSInt Result = EVResult.Val.getInt();
8701 const uint64_t SamplerValue = Result.getLimitedValue();
8702 // 32-bit value of sampler's initializer is interpreted as
8703 // bit-field with the following structure:
8704 // |unspecified|Filter|Addressing Mode| Normalized Coords|
8705 // |31 6|5 4|3 1| 0|
8706 // This structure corresponds to enum values of sampler properties
8707 // defined in SPIR spec v1.2 and also opencl-c.h
8708 unsigned AddressingMode = (0x0E & SamplerValue) >> 1;
8709 unsigned FilterMode = (0x30 & SamplerValue) >> 4;
8710 if (FilterMode != 1 && FilterMode != 2 &&
8711 !S.getOpenCLOptions().isEnabled(
8712 "cl_intel_device_side_avc_motion_estimation"))
8713 S.Diag(Kind.getLocation(),
8714 diag::warn_sampler_initializer_invalid_bits)
8715 << "Filter Mode";
8716 if (AddressingMode > 4)
8717 S.Diag(Kind.getLocation(),
8718 diag::warn_sampler_initializer_invalid_bits)
8719 << "Addressing Mode";
8720 }
8721
8722 // Cases 1a, 2a and 2b
8723 // Insert cast from integer to sampler.
8724 CurInit = S.ImpCastExprToType(Init, S.Context.OCLSamplerTy,
8725 CK_IntToOCLSampler);
8726 break;
8727 }
8728 case SK_OCLZeroOpaqueType: {
8729 assert((Step->Type->isEventT() || Step->Type->isQueueT() ||
8730 Step->Type->isOCLIntelSubgroupAVCType()) &&
8731 "Wrong type for initialization of OpenCL opaque type.");
8732
8733 CurInit = S.ImpCastExprToType(CurInit.get(), Step->Type,
8734 CK_ZeroToOCLOpaqueType,
8735 CurInit.get()->getValueKind());
8736 break;
8737 }
8738 }
8739 }
8740
8741 // Check whether the initializer has a shorter lifetime than the initialized
8742 // entity, and if not, either lifetime-extend or warn as appropriate.
8743 if (auto *Init = CurInit.get())
8744 S.checkInitializerLifetime(Entity, Init);
8745
8746 // Diagnose non-fatal problems with the completed initialization.
8747 if (Entity.getKind() == InitializedEntity::EK_Member &&
8748 cast<FieldDecl>(Entity.getDecl())->isBitField())
8749 S.CheckBitFieldInitialization(Kind.getLocation(),
8750 cast<FieldDecl>(Entity.getDecl()),
8751 CurInit.get());
8752
8753 // Check for std::move on construction.
8754 if (const Expr *E = CurInit.get()) {
8755 CheckMoveOnConstruction(S, E,
8756 Entity.getKind() == InitializedEntity::EK_Result);
8757 }
8758
8759 return CurInit;
8760 }
8761
8762 /// Somewhere within T there is an uninitialized reference subobject.
8763 /// Dig it out and diagnose it.
DiagnoseUninitializedReference(Sema & S,SourceLocation Loc,QualType T)8764 static bool DiagnoseUninitializedReference(Sema &S, SourceLocation Loc,
8765 QualType T) {
8766 if (T->isReferenceType()) {
8767 S.Diag(Loc, diag::err_reference_without_init)
8768 << T.getNonReferenceType();
8769 return true;
8770 }
8771
8772 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
8773 if (!RD || !RD->hasUninitializedReferenceMember())
8774 return false;
8775
8776 for (const auto *FI : RD->fields()) {
8777 if (FI->isUnnamedBitfield())
8778 continue;
8779
8780 if (DiagnoseUninitializedReference(S, FI->getLocation(), FI->getType())) {
8781 S.Diag(Loc, diag::note_value_initialization_here) << RD;
8782 return true;
8783 }
8784 }
8785
8786 for (const auto &BI : RD->bases()) {
8787 if (DiagnoseUninitializedReference(S, BI.getBeginLoc(), BI.getType())) {
8788 S.Diag(Loc, diag::note_value_initialization_here) << RD;
8789 return true;
8790 }
8791 }
8792
8793 return false;
8794 }
8795
8796
8797 //===----------------------------------------------------------------------===//
8798 // Diagnose initialization failures
8799 //===----------------------------------------------------------------------===//
8800
8801 /// Emit notes associated with an initialization that failed due to a
8802 /// "simple" conversion failure.
emitBadConversionNotes(Sema & S,const InitializedEntity & entity,Expr * op)8803 static void emitBadConversionNotes(Sema &S, const InitializedEntity &entity,
8804 Expr *op) {
8805 QualType destType = entity.getType();
8806 if (destType.getNonReferenceType()->isObjCObjectPointerType() &&
8807 op->getType()->isObjCObjectPointerType()) {
8808
8809 // Emit a possible note about the conversion failing because the
8810 // operand is a message send with a related result type.
8811 S.EmitRelatedResultTypeNote(op);
8812
8813 // Emit a possible note about a return failing because we're
8814 // expecting a related result type.
8815 if (entity.getKind() == InitializedEntity::EK_Result)
8816 S.EmitRelatedResultTypeNoteForReturn(destType);
8817 }
8818 QualType fromType = op->getType();
8819 auto *fromDecl = fromType.getTypePtr()->getPointeeCXXRecordDecl();
8820 auto *destDecl = destType.getTypePtr()->getPointeeCXXRecordDecl();
8821 if (fromDecl && destDecl && fromDecl->getDeclKind() == Decl::CXXRecord &&
8822 destDecl->getDeclKind() == Decl::CXXRecord &&
8823 !fromDecl->isInvalidDecl() && !destDecl->isInvalidDecl() &&
8824 !fromDecl->hasDefinition())
8825 S.Diag(fromDecl->getLocation(), diag::note_forward_class_conversion)
8826 << S.getASTContext().getTagDeclType(fromDecl)
8827 << S.getASTContext().getTagDeclType(destDecl);
8828 }
8829
diagnoseListInit(Sema & S,const InitializedEntity & Entity,InitListExpr * InitList)8830 static void diagnoseListInit(Sema &S, const InitializedEntity &Entity,
8831 InitListExpr *InitList) {
8832 QualType DestType = Entity.getType();
8833
8834 QualType E;
8835 if (S.getLangOpts().CPlusPlus11 && S.isStdInitializerList(DestType, &E)) {
8836 QualType ArrayType = S.Context.getConstantArrayType(
8837 E.withConst(),
8838 llvm::APInt(S.Context.getTypeSize(S.Context.getSizeType()),
8839 InitList->getNumInits()),
8840 nullptr, clang::ArrayType::Normal, 0);
8841 InitializedEntity HiddenArray =
8842 InitializedEntity::InitializeTemporary(ArrayType);
8843 return diagnoseListInit(S, HiddenArray, InitList);
8844 }
8845
8846 if (DestType->isReferenceType()) {
8847 // A list-initialization failure for a reference means that we tried to
8848 // create a temporary of the inner type (per [dcl.init.list]p3.6) and the
8849 // inner initialization failed.
8850 QualType T = DestType->castAs<ReferenceType>()->getPointeeType();
8851 diagnoseListInit(S, InitializedEntity::InitializeTemporary(T), InitList);
8852 SourceLocation Loc = InitList->getBeginLoc();
8853 if (auto *D = Entity.getDecl())
8854 Loc = D->getLocation();
8855 S.Diag(Loc, diag::note_in_reference_temporary_list_initializer) << T;
8856 return;
8857 }
8858
8859 InitListChecker DiagnoseInitList(S, Entity, InitList, DestType,
8860 /*VerifyOnly=*/false,
8861 /*TreatUnavailableAsInvalid=*/false);
8862 assert(DiagnoseInitList.HadError() &&
8863 "Inconsistent init list check result.");
8864 }
8865
Diagnose(Sema & S,const InitializedEntity & Entity,const InitializationKind & Kind,ArrayRef<Expr * > Args)8866 bool InitializationSequence::Diagnose(Sema &S,
8867 const InitializedEntity &Entity,
8868 const InitializationKind &Kind,
8869 ArrayRef<Expr *> Args) {
8870 if (!Failed())
8871 return false;
8872
8873 // When we want to diagnose only one element of a braced-init-list,
8874 // we need to factor it out.
8875 Expr *OnlyArg;
8876 if (Args.size() == 1) {
8877 auto *List = dyn_cast<InitListExpr>(Args[0]);
8878 if (List && List->getNumInits() == 1)
8879 OnlyArg = List->getInit(0);
8880 else
8881 OnlyArg = Args[0];
8882 }
8883 else
8884 OnlyArg = nullptr;
8885
8886 QualType DestType = Entity.getType();
8887 switch (Failure) {
8888 case FK_TooManyInitsForReference:
8889 // FIXME: Customize for the initialized entity?
8890 if (Args.empty()) {
8891 // Dig out the reference subobject which is uninitialized and diagnose it.
8892 // If this is value-initialization, this could be nested some way within
8893 // the target type.
8894 assert(Kind.getKind() == InitializationKind::IK_Value ||
8895 DestType->isReferenceType());
8896 bool Diagnosed =
8897 DiagnoseUninitializedReference(S, Kind.getLocation(), DestType);
8898 assert(Diagnosed && "couldn't find uninitialized reference to diagnose");
8899 (void)Diagnosed;
8900 } else // FIXME: diagnostic below could be better!
8901 S.Diag(Kind.getLocation(), diag::err_reference_has_multiple_inits)
8902 << SourceRange(Args.front()->getBeginLoc(), Args.back()->getEndLoc());
8903 break;
8904 case FK_ParenthesizedListInitForReference:
8905 S.Diag(Kind.getLocation(), diag::err_list_init_in_parens)
8906 << 1 << Entity.getType() << Args[0]->getSourceRange();
8907 break;
8908
8909 case FK_ArrayNeedsInitList:
8910 S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 0;
8911 break;
8912 case FK_ArrayNeedsInitListOrStringLiteral:
8913 S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 1;
8914 break;
8915 case FK_ArrayNeedsInitListOrWideStringLiteral:
8916 S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 2;
8917 break;
8918 case FK_NarrowStringIntoWideCharArray:
8919 S.Diag(Kind.getLocation(), diag::err_array_init_narrow_string_into_wchar);
8920 break;
8921 case FK_WideStringIntoCharArray:
8922 S.Diag(Kind.getLocation(), diag::err_array_init_wide_string_into_char);
8923 break;
8924 case FK_IncompatWideStringIntoWideChar:
8925 S.Diag(Kind.getLocation(),
8926 diag::err_array_init_incompat_wide_string_into_wchar);
8927 break;
8928 case FK_PlainStringIntoUTF8Char:
8929 S.Diag(Kind.getLocation(),
8930 diag::err_array_init_plain_string_into_char8_t);
8931 S.Diag(Args.front()->getBeginLoc(),
8932 diag::note_array_init_plain_string_into_char8_t)
8933 << FixItHint::CreateInsertion(Args.front()->getBeginLoc(), "u8");
8934 break;
8935 case FK_UTF8StringIntoPlainChar:
8936 S.Diag(Kind.getLocation(),
8937 diag::err_array_init_utf8_string_into_char)
8938 << S.getLangOpts().CPlusPlus20;
8939 break;
8940 case FK_ArrayTypeMismatch:
8941 case FK_NonConstantArrayInit:
8942 S.Diag(Kind.getLocation(),
8943 (Failure == FK_ArrayTypeMismatch
8944 ? diag::err_array_init_different_type
8945 : diag::err_array_init_non_constant_array))
8946 << DestType.getNonReferenceType()
8947 << OnlyArg->getType()
8948 << Args[0]->getSourceRange();
8949 break;
8950
8951 case FK_VariableLengthArrayHasInitializer:
8952 S.Diag(Kind.getLocation(), diag::err_variable_object_no_init)
8953 << Args[0]->getSourceRange();
8954 break;
8955
8956 case FK_AddressOfOverloadFailed: {
8957 DeclAccessPair Found;
8958 S.ResolveAddressOfOverloadedFunction(OnlyArg,
8959 DestType.getNonReferenceType(),
8960 true,
8961 Found);
8962 break;
8963 }
8964
8965 case FK_AddressOfUnaddressableFunction: {
8966 auto *FD = cast<FunctionDecl>(cast<DeclRefExpr>(OnlyArg)->getDecl());
8967 S.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true,
8968 OnlyArg->getBeginLoc());
8969 break;
8970 }
8971
8972 case FK_ReferenceInitOverloadFailed:
8973 case FK_UserConversionOverloadFailed:
8974 switch (FailedOverloadResult) {
8975 case OR_Ambiguous:
8976
8977 FailedCandidateSet.NoteCandidates(
8978 PartialDiagnosticAt(
8979 Kind.getLocation(),
8980 Failure == FK_UserConversionOverloadFailed
8981 ? (S.PDiag(diag::err_typecheck_ambiguous_condition)
8982 << OnlyArg->getType() << DestType
8983 << Args[0]->getSourceRange())
8984 : (S.PDiag(diag::err_ref_init_ambiguous)
8985 << DestType << OnlyArg->getType()
8986 << Args[0]->getSourceRange())),
8987 S, OCD_AmbiguousCandidates, Args);
8988 break;
8989
8990 case OR_No_Viable_Function: {
8991 auto Cands = FailedCandidateSet.CompleteCandidates(S, OCD_AllCandidates, Args);
8992 if (!S.RequireCompleteType(Kind.getLocation(),
8993 DestType.getNonReferenceType(),
8994 diag::err_typecheck_nonviable_condition_incomplete,
8995 OnlyArg->getType(), Args[0]->getSourceRange()))
8996 S.Diag(Kind.getLocation(), diag::err_typecheck_nonviable_condition)
8997 << (Entity.getKind() == InitializedEntity::EK_Result)
8998 << OnlyArg->getType() << Args[0]->getSourceRange()
8999 << DestType.getNonReferenceType();
9000
9001 FailedCandidateSet.NoteCandidates(S, Args, Cands);
9002 break;
9003 }
9004 case OR_Deleted: {
9005 S.Diag(Kind.getLocation(), diag::err_typecheck_deleted_function)
9006 << OnlyArg->getType() << DestType.getNonReferenceType()
9007 << Args[0]->getSourceRange();
9008 OverloadCandidateSet::iterator Best;
9009 OverloadingResult Ovl
9010 = FailedCandidateSet.BestViableFunction(S, Kind.getLocation(), Best);
9011 if (Ovl == OR_Deleted) {
9012 S.NoteDeletedFunction(Best->Function);
9013 } else {
9014 llvm_unreachable("Inconsistent overload resolution?");
9015 }
9016 break;
9017 }
9018
9019 case OR_Success:
9020 llvm_unreachable("Conversion did not fail!");
9021 }
9022 break;
9023
9024 case FK_NonConstLValueReferenceBindingToTemporary:
9025 if (isa<InitListExpr>(Args[0])) {
9026 S.Diag(Kind.getLocation(),
9027 diag::err_lvalue_reference_bind_to_initlist)
9028 << DestType.getNonReferenceType().isVolatileQualified()
9029 << DestType.getNonReferenceType()
9030 << Args[0]->getSourceRange();
9031 break;
9032 }
9033 LLVM_FALLTHROUGH;
9034
9035 case FK_NonConstLValueReferenceBindingToUnrelated:
9036 S.Diag(Kind.getLocation(),
9037 Failure == FK_NonConstLValueReferenceBindingToTemporary
9038 ? diag::err_lvalue_reference_bind_to_temporary
9039 : diag::err_lvalue_reference_bind_to_unrelated)
9040 << DestType.getNonReferenceType().isVolatileQualified()
9041 << DestType.getNonReferenceType()
9042 << OnlyArg->getType()
9043 << Args[0]->getSourceRange();
9044 break;
9045
9046 case FK_NonConstLValueReferenceBindingToBitfield: {
9047 // We don't necessarily have an unambiguous source bit-field.
9048 FieldDecl *BitField = Args[0]->getSourceBitField();
9049 S.Diag(Kind.getLocation(), diag::err_reference_bind_to_bitfield)
9050 << DestType.isVolatileQualified()
9051 << (BitField ? BitField->getDeclName() : DeclarationName())
9052 << (BitField != nullptr)
9053 << Args[0]->getSourceRange();
9054 if (BitField)
9055 S.Diag(BitField->getLocation(), diag::note_bitfield_decl);
9056 break;
9057 }
9058
9059 case FK_NonConstLValueReferenceBindingToVectorElement:
9060 S.Diag(Kind.getLocation(), diag::err_reference_bind_to_vector_element)
9061 << DestType.isVolatileQualified()
9062 << Args[0]->getSourceRange();
9063 break;
9064
9065 case FK_NonConstLValueReferenceBindingToMatrixElement:
9066 S.Diag(Kind.getLocation(), diag::err_reference_bind_to_matrix_element)
9067 << DestType.isVolatileQualified() << Args[0]->getSourceRange();
9068 break;
9069
9070 case FK_RValueReferenceBindingToLValue:
9071 S.Diag(Kind.getLocation(), diag::err_lvalue_to_rvalue_ref)
9072 << DestType.getNonReferenceType() << OnlyArg->getType()
9073 << Args[0]->getSourceRange();
9074 break;
9075
9076 case FK_ReferenceAddrspaceMismatchTemporary:
9077 S.Diag(Kind.getLocation(), diag::err_reference_bind_temporary_addrspace)
9078 << DestType << Args[0]->getSourceRange();
9079 break;
9080
9081 case FK_ReferenceInitDropsQualifiers: {
9082 QualType SourceType = OnlyArg->getType();
9083 QualType NonRefType = DestType.getNonReferenceType();
9084 Qualifiers DroppedQualifiers =
9085 SourceType.getQualifiers() - NonRefType.getQualifiers();
9086
9087 if (!NonRefType.getQualifiers().isAddressSpaceSupersetOf(
9088 SourceType.getQualifiers()))
9089 S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
9090 << NonRefType << SourceType << 1 /*addr space*/
9091 << Args[0]->getSourceRange();
9092 else if (DroppedQualifiers.hasQualifiers())
9093 S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
9094 << NonRefType << SourceType << 0 /*cv quals*/
9095 << Qualifiers::fromCVRMask(DroppedQualifiers.getCVRQualifiers())
9096 << DroppedQualifiers.getCVRQualifiers() << Args[0]->getSourceRange();
9097 else
9098 // FIXME: Consider decomposing the type and explaining which qualifiers
9099 // were dropped where, or on which level a 'const' is missing, etc.
9100 S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
9101 << NonRefType << SourceType << 2 /*incompatible quals*/
9102 << Args[0]->getSourceRange();
9103 break;
9104 }
9105
9106 case FK_ReferenceInitFailed:
9107 S.Diag(Kind.getLocation(), diag::err_reference_bind_failed)
9108 << DestType.getNonReferenceType()
9109 << DestType.getNonReferenceType()->isIncompleteType()
9110 << OnlyArg->isLValue()
9111 << OnlyArg->getType()
9112 << Args[0]->getSourceRange();
9113 emitBadConversionNotes(S, Entity, Args[0]);
9114 break;
9115
9116 case FK_ConversionFailed: {
9117 QualType FromType = OnlyArg->getType();
9118 PartialDiagnostic PDiag = S.PDiag(diag::err_init_conversion_failed)
9119 << (int)Entity.getKind()
9120 << DestType
9121 << OnlyArg->isLValue()
9122 << FromType
9123 << Args[0]->getSourceRange();
9124 S.HandleFunctionTypeMismatch(PDiag, FromType, DestType);
9125 S.Diag(Kind.getLocation(), PDiag);
9126 emitBadConversionNotes(S, Entity, Args[0]);
9127 break;
9128 }
9129
9130 case FK_ConversionFromPropertyFailed:
9131 // No-op. This error has already been reported.
9132 break;
9133
9134 case FK_TooManyInitsForScalar: {
9135 SourceRange R;
9136
9137 auto *InitList = dyn_cast<InitListExpr>(Args[0]);
9138 if (InitList && InitList->getNumInits() >= 1) {
9139 R = SourceRange(InitList->getInit(0)->getEndLoc(), InitList->getEndLoc());
9140 } else {
9141 assert(Args.size() > 1 && "Expected multiple initializers!");
9142 R = SourceRange(Args.front()->getEndLoc(), Args.back()->getEndLoc());
9143 }
9144
9145 R.setBegin(S.getLocForEndOfToken(R.getBegin()));
9146 if (Kind.isCStyleOrFunctionalCast())
9147 S.Diag(Kind.getLocation(), diag::err_builtin_func_cast_more_than_one_arg)
9148 << R;
9149 else
9150 S.Diag(Kind.getLocation(), diag::err_excess_initializers)
9151 << /*scalar=*/2 << R;
9152 break;
9153 }
9154
9155 case FK_ParenthesizedListInitForScalar:
9156 S.Diag(Kind.getLocation(), diag::err_list_init_in_parens)
9157 << 0 << Entity.getType() << Args[0]->getSourceRange();
9158 break;
9159
9160 case FK_ReferenceBindingToInitList:
9161 S.Diag(Kind.getLocation(), diag::err_reference_bind_init_list)
9162 << DestType.getNonReferenceType() << Args[0]->getSourceRange();
9163 break;
9164
9165 case FK_InitListBadDestinationType:
9166 S.Diag(Kind.getLocation(), diag::err_init_list_bad_dest_type)
9167 << (DestType->isRecordType()) << DestType << Args[0]->getSourceRange();
9168 break;
9169
9170 case FK_ListConstructorOverloadFailed:
9171 case FK_ConstructorOverloadFailed: {
9172 SourceRange ArgsRange;
9173 if (Args.size())
9174 ArgsRange =
9175 SourceRange(Args.front()->getBeginLoc(), Args.back()->getEndLoc());
9176
9177 if (Failure == FK_ListConstructorOverloadFailed) {
9178 assert(Args.size() == 1 &&
9179 "List construction from other than 1 argument.");
9180 InitListExpr *InitList = cast<InitListExpr>(Args[0]);
9181 Args = MultiExprArg(InitList->getInits(), InitList->getNumInits());
9182 }
9183
9184 // FIXME: Using "DestType" for the entity we're printing is probably
9185 // bad.
9186 switch (FailedOverloadResult) {
9187 case OR_Ambiguous:
9188 FailedCandidateSet.NoteCandidates(
9189 PartialDiagnosticAt(Kind.getLocation(),
9190 S.PDiag(diag::err_ovl_ambiguous_init)
9191 << DestType << ArgsRange),
9192 S, OCD_AmbiguousCandidates, Args);
9193 break;
9194
9195 case OR_No_Viable_Function:
9196 if (Kind.getKind() == InitializationKind::IK_Default &&
9197 (Entity.getKind() == InitializedEntity::EK_Base ||
9198 Entity.getKind() == InitializedEntity::EK_Member) &&
9199 isa<CXXConstructorDecl>(S.CurContext)) {
9200 // This is implicit default initialization of a member or
9201 // base within a constructor. If no viable function was
9202 // found, notify the user that they need to explicitly
9203 // initialize this base/member.
9204 CXXConstructorDecl *Constructor
9205 = cast<CXXConstructorDecl>(S.CurContext);
9206 const CXXRecordDecl *InheritedFrom = nullptr;
9207 if (auto Inherited = Constructor->getInheritedConstructor())
9208 InheritedFrom = Inherited.getShadowDecl()->getNominatedBaseClass();
9209 if (Entity.getKind() == InitializedEntity::EK_Base) {
9210 S.Diag(Kind.getLocation(), diag::err_missing_default_ctor)
9211 << (InheritedFrom ? 2 : Constructor->isImplicit() ? 1 : 0)
9212 << S.Context.getTypeDeclType(Constructor->getParent())
9213 << /*base=*/0
9214 << Entity.getType()
9215 << InheritedFrom;
9216
9217 RecordDecl *BaseDecl
9218 = Entity.getBaseSpecifier()->getType()->castAs<RecordType>()
9219 ->getDecl();
9220 S.Diag(BaseDecl->getLocation(), diag::note_previous_decl)
9221 << S.Context.getTagDeclType(BaseDecl);
9222 } else {
9223 S.Diag(Kind.getLocation(), diag::err_missing_default_ctor)
9224 << (InheritedFrom ? 2 : Constructor->isImplicit() ? 1 : 0)
9225 << S.Context.getTypeDeclType(Constructor->getParent())
9226 << /*member=*/1
9227 << Entity.getName()
9228 << InheritedFrom;
9229 S.Diag(Entity.getDecl()->getLocation(),
9230 diag::note_member_declared_at);
9231
9232 if (const RecordType *Record
9233 = Entity.getType()->getAs<RecordType>())
9234 S.Diag(Record->getDecl()->getLocation(),
9235 diag::note_previous_decl)
9236 << S.Context.getTagDeclType(Record->getDecl());
9237 }
9238 break;
9239 }
9240
9241 FailedCandidateSet.NoteCandidates(
9242 PartialDiagnosticAt(
9243 Kind.getLocation(),
9244 S.PDiag(diag::err_ovl_no_viable_function_in_init)
9245 << DestType << ArgsRange),
9246 S, OCD_AllCandidates, Args);
9247 break;
9248
9249 case OR_Deleted: {
9250 OverloadCandidateSet::iterator Best;
9251 OverloadingResult Ovl
9252 = FailedCandidateSet.BestViableFunction(S, Kind.getLocation(), Best);
9253 if (Ovl != OR_Deleted) {
9254 S.Diag(Kind.getLocation(), diag::err_ovl_deleted_init)
9255 << DestType << ArgsRange;
9256 llvm_unreachable("Inconsistent overload resolution?");
9257 break;
9258 }
9259
9260 // If this is a defaulted or implicitly-declared function, then
9261 // it was implicitly deleted. Make it clear that the deletion was
9262 // implicit.
9263 if (S.isImplicitlyDeleted(Best->Function))
9264 S.Diag(Kind.getLocation(), diag::err_ovl_deleted_special_init)
9265 << S.getSpecialMember(cast<CXXMethodDecl>(Best->Function))
9266 << DestType << ArgsRange;
9267 else
9268 S.Diag(Kind.getLocation(), diag::err_ovl_deleted_init)
9269 << DestType << ArgsRange;
9270
9271 S.NoteDeletedFunction(Best->Function);
9272 break;
9273 }
9274
9275 case OR_Success:
9276 llvm_unreachable("Conversion did not fail!");
9277 }
9278 }
9279 break;
9280
9281 case FK_DefaultInitOfConst:
9282 if (Entity.getKind() == InitializedEntity::EK_Member &&
9283 isa<CXXConstructorDecl>(S.CurContext)) {
9284 // This is implicit default-initialization of a const member in
9285 // a constructor. Complain that it needs to be explicitly
9286 // initialized.
9287 CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(S.CurContext);
9288 S.Diag(Kind.getLocation(), diag::err_uninitialized_member_in_ctor)
9289 << (Constructor->getInheritedConstructor() ? 2 :
9290 Constructor->isImplicit() ? 1 : 0)
9291 << S.Context.getTypeDeclType(Constructor->getParent())
9292 << /*const=*/1
9293 << Entity.getName();
9294 S.Diag(Entity.getDecl()->getLocation(), diag::note_previous_decl)
9295 << Entity.getName();
9296 } else {
9297 S.Diag(Kind.getLocation(), diag::err_default_init_const)
9298 << DestType << (bool)DestType->getAs<RecordType>();
9299 }
9300 break;
9301
9302 case FK_Incomplete:
9303 S.RequireCompleteType(Kind.getLocation(), FailedIncompleteType,
9304 diag::err_init_incomplete_type);
9305 break;
9306
9307 case FK_ListInitializationFailed: {
9308 // Run the init list checker again to emit diagnostics.
9309 InitListExpr *InitList = cast<InitListExpr>(Args[0]);
9310 diagnoseListInit(S, Entity, InitList);
9311 break;
9312 }
9313
9314 case FK_PlaceholderType: {
9315 // FIXME: Already diagnosed!
9316 break;
9317 }
9318
9319 case FK_ExplicitConstructor: {
9320 S.Diag(Kind.getLocation(), diag::err_selected_explicit_constructor)
9321 << Args[0]->getSourceRange();
9322 OverloadCandidateSet::iterator Best;
9323 OverloadingResult Ovl
9324 = FailedCandidateSet.BestViableFunction(S, Kind.getLocation(), Best);
9325 (void)Ovl;
9326 assert(Ovl == OR_Success && "Inconsistent overload resolution");
9327 CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
9328 S.Diag(CtorDecl->getLocation(),
9329 diag::note_explicit_ctor_deduction_guide_here) << false;
9330 break;
9331 }
9332 }
9333
9334 PrintInitLocationNote(S, Entity);
9335 return true;
9336 }
9337
dump(raw_ostream & OS) const9338 void InitializationSequence::dump(raw_ostream &OS) const {
9339 switch (SequenceKind) {
9340 case FailedSequence: {
9341 OS << "Failed sequence: ";
9342 switch (Failure) {
9343 case FK_TooManyInitsForReference:
9344 OS << "too many initializers for reference";
9345 break;
9346
9347 case FK_ParenthesizedListInitForReference:
9348 OS << "parenthesized list init for reference";
9349 break;
9350
9351 case FK_ArrayNeedsInitList:
9352 OS << "array requires initializer list";
9353 break;
9354
9355 case FK_AddressOfUnaddressableFunction:
9356 OS << "address of unaddressable function was taken";
9357 break;
9358
9359 case FK_ArrayNeedsInitListOrStringLiteral:
9360 OS << "array requires initializer list or string literal";
9361 break;
9362
9363 case FK_ArrayNeedsInitListOrWideStringLiteral:
9364 OS << "array requires initializer list or wide string literal";
9365 break;
9366
9367 case FK_NarrowStringIntoWideCharArray:
9368 OS << "narrow string into wide char array";
9369 break;
9370
9371 case FK_WideStringIntoCharArray:
9372 OS << "wide string into char array";
9373 break;
9374
9375 case FK_IncompatWideStringIntoWideChar:
9376 OS << "incompatible wide string into wide char array";
9377 break;
9378
9379 case FK_PlainStringIntoUTF8Char:
9380 OS << "plain string literal into char8_t array";
9381 break;
9382
9383 case FK_UTF8StringIntoPlainChar:
9384 OS << "u8 string literal into char array";
9385 break;
9386
9387 case FK_ArrayTypeMismatch:
9388 OS << "array type mismatch";
9389 break;
9390
9391 case FK_NonConstantArrayInit:
9392 OS << "non-constant array initializer";
9393 break;
9394
9395 case FK_AddressOfOverloadFailed:
9396 OS << "address of overloaded function failed";
9397 break;
9398
9399 case FK_ReferenceInitOverloadFailed:
9400 OS << "overload resolution for reference initialization failed";
9401 break;
9402
9403 case FK_NonConstLValueReferenceBindingToTemporary:
9404 OS << "non-const lvalue reference bound to temporary";
9405 break;
9406
9407 case FK_NonConstLValueReferenceBindingToBitfield:
9408 OS << "non-const lvalue reference bound to bit-field";
9409 break;
9410
9411 case FK_NonConstLValueReferenceBindingToVectorElement:
9412 OS << "non-const lvalue reference bound to vector element";
9413 break;
9414
9415 case FK_NonConstLValueReferenceBindingToMatrixElement:
9416 OS << "non-const lvalue reference bound to matrix element";
9417 break;
9418
9419 case FK_NonConstLValueReferenceBindingToUnrelated:
9420 OS << "non-const lvalue reference bound to unrelated type";
9421 break;
9422
9423 case FK_RValueReferenceBindingToLValue:
9424 OS << "rvalue reference bound to an lvalue";
9425 break;
9426
9427 case FK_ReferenceInitDropsQualifiers:
9428 OS << "reference initialization drops qualifiers";
9429 break;
9430
9431 case FK_ReferenceAddrspaceMismatchTemporary:
9432 OS << "reference with mismatching address space bound to temporary";
9433 break;
9434
9435 case FK_ReferenceInitFailed:
9436 OS << "reference initialization failed";
9437 break;
9438
9439 case FK_ConversionFailed:
9440 OS << "conversion failed";
9441 break;
9442
9443 case FK_ConversionFromPropertyFailed:
9444 OS << "conversion from property failed";
9445 break;
9446
9447 case FK_TooManyInitsForScalar:
9448 OS << "too many initializers for scalar";
9449 break;
9450
9451 case FK_ParenthesizedListInitForScalar:
9452 OS << "parenthesized list init for reference";
9453 break;
9454
9455 case FK_ReferenceBindingToInitList:
9456 OS << "referencing binding to initializer list";
9457 break;
9458
9459 case FK_InitListBadDestinationType:
9460 OS << "initializer list for non-aggregate, non-scalar type";
9461 break;
9462
9463 case FK_UserConversionOverloadFailed:
9464 OS << "overloading failed for user-defined conversion";
9465 break;
9466
9467 case FK_ConstructorOverloadFailed:
9468 OS << "constructor overloading failed";
9469 break;
9470
9471 case FK_DefaultInitOfConst:
9472 OS << "default initialization of a const variable";
9473 break;
9474
9475 case FK_Incomplete:
9476 OS << "initialization of incomplete type";
9477 break;
9478
9479 case FK_ListInitializationFailed:
9480 OS << "list initialization checker failure";
9481 break;
9482
9483 case FK_VariableLengthArrayHasInitializer:
9484 OS << "variable length array has an initializer";
9485 break;
9486
9487 case FK_PlaceholderType:
9488 OS << "initializer expression isn't contextually valid";
9489 break;
9490
9491 case FK_ListConstructorOverloadFailed:
9492 OS << "list constructor overloading failed";
9493 break;
9494
9495 case FK_ExplicitConstructor:
9496 OS << "list copy initialization chose explicit constructor";
9497 break;
9498 }
9499 OS << '\n';
9500 return;
9501 }
9502
9503 case DependentSequence:
9504 OS << "Dependent sequence\n";
9505 return;
9506
9507 case NormalSequence:
9508 OS << "Normal sequence: ";
9509 break;
9510 }
9511
9512 for (step_iterator S = step_begin(), SEnd = step_end(); S != SEnd; ++S) {
9513 if (S != step_begin()) {
9514 OS << " -> ";
9515 }
9516
9517 switch (S->Kind) {
9518 case SK_ResolveAddressOfOverloadedFunction:
9519 OS << "resolve address of overloaded function";
9520 break;
9521
9522 case SK_CastDerivedToBaseRValue:
9523 OS << "derived-to-base (rvalue)";
9524 break;
9525
9526 case SK_CastDerivedToBaseXValue:
9527 OS << "derived-to-base (xvalue)";
9528 break;
9529
9530 case SK_CastDerivedToBaseLValue:
9531 OS << "derived-to-base (lvalue)";
9532 break;
9533
9534 case SK_BindReference:
9535 OS << "bind reference to lvalue";
9536 break;
9537
9538 case SK_BindReferenceToTemporary:
9539 OS << "bind reference to a temporary";
9540 break;
9541
9542 case SK_FinalCopy:
9543 OS << "final copy in class direct-initialization";
9544 break;
9545
9546 case SK_ExtraneousCopyToTemporary:
9547 OS << "extraneous C++03 copy to temporary";
9548 break;
9549
9550 case SK_UserConversion:
9551 OS << "user-defined conversion via " << *S->Function.Function;
9552 break;
9553
9554 case SK_QualificationConversionRValue:
9555 OS << "qualification conversion (rvalue)";
9556 break;
9557
9558 case SK_QualificationConversionXValue:
9559 OS << "qualification conversion (xvalue)";
9560 break;
9561
9562 case SK_QualificationConversionLValue:
9563 OS << "qualification conversion (lvalue)";
9564 break;
9565
9566 case SK_AtomicConversion:
9567 OS << "non-atomic-to-atomic conversion";
9568 break;
9569
9570 case SK_ConversionSequence:
9571 OS << "implicit conversion sequence (";
9572 S->ICS->dump(); // FIXME: use OS
9573 OS << ")";
9574 break;
9575
9576 case SK_ConversionSequenceNoNarrowing:
9577 OS << "implicit conversion sequence with narrowing prohibited (";
9578 S->ICS->dump(); // FIXME: use OS
9579 OS << ")";
9580 break;
9581
9582 case SK_ListInitialization:
9583 OS << "list aggregate initialization";
9584 break;
9585
9586 case SK_UnwrapInitList:
9587 OS << "unwrap reference initializer list";
9588 break;
9589
9590 case SK_RewrapInitList:
9591 OS << "rewrap reference initializer list";
9592 break;
9593
9594 case SK_ConstructorInitialization:
9595 OS << "constructor initialization";
9596 break;
9597
9598 case SK_ConstructorInitializationFromList:
9599 OS << "list initialization via constructor";
9600 break;
9601
9602 case SK_ZeroInitialization:
9603 OS << "zero initialization";
9604 break;
9605
9606 case SK_CAssignment:
9607 OS << "C assignment";
9608 break;
9609
9610 case SK_StringInit:
9611 OS << "string initialization";
9612 break;
9613
9614 case SK_ObjCObjectConversion:
9615 OS << "Objective-C object conversion";
9616 break;
9617
9618 case SK_ArrayLoopIndex:
9619 OS << "indexing for array initialization loop";
9620 break;
9621
9622 case SK_ArrayLoopInit:
9623 OS << "array initialization loop";
9624 break;
9625
9626 case SK_ArrayInit:
9627 OS << "array initialization";
9628 break;
9629
9630 case SK_GNUArrayInit:
9631 OS << "array initialization (GNU extension)";
9632 break;
9633
9634 case SK_ParenthesizedArrayInit:
9635 OS << "parenthesized array initialization";
9636 break;
9637
9638 case SK_PassByIndirectCopyRestore:
9639 OS << "pass by indirect copy and restore";
9640 break;
9641
9642 case SK_PassByIndirectRestore:
9643 OS << "pass by indirect restore";
9644 break;
9645
9646 case SK_ProduceObjCObject:
9647 OS << "Objective-C object retension";
9648 break;
9649
9650 case SK_StdInitializerList:
9651 OS << "std::initializer_list from initializer list";
9652 break;
9653
9654 case SK_StdInitializerListConstructorCall:
9655 OS << "list initialization from std::initializer_list";
9656 break;
9657
9658 case SK_OCLSamplerInit:
9659 OS << "OpenCL sampler_t from integer constant";
9660 break;
9661
9662 case SK_OCLZeroOpaqueType:
9663 OS << "OpenCL opaque type from zero";
9664 break;
9665 }
9666
9667 OS << " [" << S->Type.getAsString() << ']';
9668 }
9669
9670 OS << '\n';
9671 }
9672
dump() const9673 void InitializationSequence::dump() const {
9674 dump(llvm::errs());
9675 }
9676
NarrowingErrs(const LangOptions & L)9677 static bool NarrowingErrs(const LangOptions &L) {
9678 return L.CPlusPlus11 &&
9679 (!L.MicrosoftExt || L.isCompatibleWithMSVC(LangOptions::MSVC2015));
9680 }
9681
DiagnoseNarrowingInInitList(Sema & S,const ImplicitConversionSequence & ICS,QualType PreNarrowingType,QualType EntityType,const Expr * PostInit)9682 static void DiagnoseNarrowingInInitList(Sema &S,
9683 const ImplicitConversionSequence &ICS,
9684 QualType PreNarrowingType,
9685 QualType EntityType,
9686 const Expr *PostInit) {
9687 const StandardConversionSequence *SCS = nullptr;
9688 switch (ICS.getKind()) {
9689 case ImplicitConversionSequence::StandardConversion:
9690 SCS = &ICS.Standard;
9691 break;
9692 case ImplicitConversionSequence::UserDefinedConversion:
9693 SCS = &ICS.UserDefined.After;
9694 break;
9695 case ImplicitConversionSequence::AmbiguousConversion:
9696 case ImplicitConversionSequence::EllipsisConversion:
9697 case ImplicitConversionSequence::BadConversion:
9698 return;
9699 }
9700
9701 // C++11 [dcl.init.list]p7: Check whether this is a narrowing conversion.
9702 APValue ConstantValue;
9703 QualType ConstantType;
9704 switch (SCS->getNarrowingKind(S.Context, PostInit, ConstantValue,
9705 ConstantType)) {
9706 case NK_Not_Narrowing:
9707 case NK_Dependent_Narrowing:
9708 // No narrowing occurred.
9709 return;
9710
9711 case NK_Type_Narrowing:
9712 // This was a floating-to-integer conversion, which is always considered a
9713 // narrowing conversion even if the value is a constant and can be
9714 // represented exactly as an integer.
9715 S.Diag(PostInit->getBeginLoc(), NarrowingErrs(S.getLangOpts())
9716 ? diag::ext_init_list_type_narrowing
9717 : diag::warn_init_list_type_narrowing)
9718 << PostInit->getSourceRange()
9719 << PreNarrowingType.getLocalUnqualifiedType()
9720 << EntityType.getLocalUnqualifiedType();
9721 break;
9722
9723 case NK_Constant_Narrowing:
9724 // A constant value was narrowed.
9725 S.Diag(PostInit->getBeginLoc(),
9726 NarrowingErrs(S.getLangOpts())
9727 ? diag::ext_init_list_constant_narrowing
9728 : diag::warn_init_list_constant_narrowing)
9729 << PostInit->getSourceRange()
9730 << ConstantValue.getAsString(S.getASTContext(), ConstantType)
9731 << EntityType.getLocalUnqualifiedType();
9732 break;
9733
9734 case NK_Variable_Narrowing:
9735 // A variable's value may have been narrowed.
9736 S.Diag(PostInit->getBeginLoc(),
9737 NarrowingErrs(S.getLangOpts())
9738 ? diag::ext_init_list_variable_narrowing
9739 : diag::warn_init_list_variable_narrowing)
9740 << PostInit->getSourceRange()
9741 << PreNarrowingType.getLocalUnqualifiedType()
9742 << EntityType.getLocalUnqualifiedType();
9743 break;
9744 }
9745
9746 SmallString<128> StaticCast;
9747 llvm::raw_svector_ostream OS(StaticCast);
9748 OS << "static_cast<";
9749 if (const TypedefType *TT = EntityType->getAs<TypedefType>()) {
9750 // It's important to use the typedef's name if there is one so that the
9751 // fixit doesn't break code using types like int64_t.
9752 //
9753 // FIXME: This will break if the typedef requires qualification. But
9754 // getQualifiedNameAsString() includes non-machine-parsable components.
9755 OS << *TT->getDecl();
9756 } else if (const BuiltinType *BT = EntityType->getAs<BuiltinType>())
9757 OS << BT->getName(S.getLangOpts());
9758 else {
9759 // Oops, we didn't find the actual type of the variable. Don't emit a fixit
9760 // with a broken cast.
9761 return;
9762 }
9763 OS << ">(";
9764 S.Diag(PostInit->getBeginLoc(), diag::note_init_list_narrowing_silence)
9765 << PostInit->getSourceRange()
9766 << FixItHint::CreateInsertion(PostInit->getBeginLoc(), OS.str())
9767 << FixItHint::CreateInsertion(
9768 S.getLocForEndOfToken(PostInit->getEndLoc()), ")");
9769 }
9770
9771 //===----------------------------------------------------------------------===//
9772 // Initialization helper functions
9773 //===----------------------------------------------------------------------===//
9774 bool
CanPerformCopyInitialization(const InitializedEntity & Entity,ExprResult Init)9775 Sema::CanPerformCopyInitialization(const InitializedEntity &Entity,
9776 ExprResult Init) {
9777 if (Init.isInvalid())
9778 return false;
9779
9780 Expr *InitE = Init.get();
9781 assert(InitE && "No initialization expression");
9782
9783 InitializationKind Kind =
9784 InitializationKind::CreateCopy(InitE->getBeginLoc(), SourceLocation());
9785 InitializationSequence Seq(*this, Entity, Kind, InitE);
9786 return !Seq.Failed();
9787 }
9788
9789 ExprResult
PerformCopyInitialization(const InitializedEntity & Entity,SourceLocation EqualLoc,ExprResult Init,bool TopLevelOfInitList,bool AllowExplicit)9790 Sema::PerformCopyInitialization(const InitializedEntity &Entity,
9791 SourceLocation EqualLoc,
9792 ExprResult Init,
9793 bool TopLevelOfInitList,
9794 bool AllowExplicit) {
9795 if (Init.isInvalid())
9796 return ExprError();
9797
9798 Expr *InitE = Init.get();
9799 assert(InitE && "No initialization expression?");
9800
9801 if (EqualLoc.isInvalid())
9802 EqualLoc = InitE->getBeginLoc();
9803
9804 InitializationKind Kind = InitializationKind::CreateCopy(
9805 InitE->getBeginLoc(), EqualLoc, AllowExplicit);
9806 InitializationSequence Seq(*this, Entity, Kind, InitE, TopLevelOfInitList);
9807
9808 // Prevent infinite recursion when performing parameter copy-initialization.
9809 const bool ShouldTrackCopy =
9810 Entity.isParameterKind() && Seq.isConstructorInitialization();
9811 if (ShouldTrackCopy) {
9812 if (llvm::find(CurrentParameterCopyTypes, Entity.getType()) !=
9813 CurrentParameterCopyTypes.end()) {
9814 Seq.SetOverloadFailure(
9815 InitializationSequence::FK_ConstructorOverloadFailed,
9816 OR_No_Viable_Function);
9817
9818 // Try to give a meaningful diagnostic note for the problematic
9819 // constructor.
9820 const auto LastStep = Seq.step_end() - 1;
9821 assert(LastStep->Kind ==
9822 InitializationSequence::SK_ConstructorInitialization);
9823 const FunctionDecl *Function = LastStep->Function.Function;
9824 auto Candidate =
9825 llvm::find_if(Seq.getFailedCandidateSet(),
9826 [Function](const OverloadCandidate &Candidate) -> bool {
9827 return Candidate.Viable &&
9828 Candidate.Function == Function &&
9829 Candidate.Conversions.size() > 0;
9830 });
9831 if (Candidate != Seq.getFailedCandidateSet().end() &&
9832 Function->getNumParams() > 0) {
9833 Candidate->Viable = false;
9834 Candidate->FailureKind = ovl_fail_bad_conversion;
9835 Candidate->Conversions[0].setBad(BadConversionSequence::no_conversion,
9836 InitE,
9837 Function->getParamDecl(0)->getType());
9838 }
9839 }
9840 CurrentParameterCopyTypes.push_back(Entity.getType());
9841 }
9842
9843 ExprResult Result = Seq.Perform(*this, Entity, Kind, InitE);
9844
9845 if (ShouldTrackCopy)
9846 CurrentParameterCopyTypes.pop_back();
9847
9848 return Result;
9849 }
9850
9851 /// Determine whether RD is, or is derived from, a specialization of CTD.
isOrIsDerivedFromSpecializationOf(CXXRecordDecl * RD,ClassTemplateDecl * CTD)9852 static bool isOrIsDerivedFromSpecializationOf(CXXRecordDecl *RD,
9853 ClassTemplateDecl *CTD) {
9854 auto NotSpecialization = [&] (const CXXRecordDecl *Candidate) {
9855 auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(Candidate);
9856 return !CTSD || !declaresSameEntity(CTSD->getSpecializedTemplate(), CTD);
9857 };
9858 return !(NotSpecialization(RD) && RD->forallBases(NotSpecialization));
9859 }
9860
DeduceTemplateSpecializationFromInitializer(TypeSourceInfo * TSInfo,const InitializedEntity & Entity,const InitializationKind & Kind,MultiExprArg Inits)9861 QualType Sema::DeduceTemplateSpecializationFromInitializer(
9862 TypeSourceInfo *TSInfo, const InitializedEntity &Entity,
9863 const InitializationKind &Kind, MultiExprArg Inits) {
9864 auto *DeducedTST = dyn_cast<DeducedTemplateSpecializationType>(
9865 TSInfo->getType()->getContainedDeducedType());
9866 assert(DeducedTST && "not a deduced template specialization type");
9867
9868 auto TemplateName = DeducedTST->getTemplateName();
9869 if (TemplateName.isDependent())
9870 return SubstAutoType(TSInfo->getType(), Context.DependentTy);
9871
9872 // We can only perform deduction for class templates.
9873 auto *Template =
9874 dyn_cast_or_null<ClassTemplateDecl>(TemplateName.getAsTemplateDecl());
9875 if (!Template) {
9876 Diag(Kind.getLocation(),
9877 diag::err_deduced_non_class_template_specialization_type)
9878 << (int)getTemplateNameKindForDiagnostics(TemplateName) << TemplateName;
9879 if (auto *TD = TemplateName.getAsTemplateDecl())
9880 Diag(TD->getLocation(), diag::note_template_decl_here);
9881 return QualType();
9882 }
9883
9884 // Can't deduce from dependent arguments.
9885 if (Expr::hasAnyTypeDependentArguments(Inits)) {
9886 Diag(TSInfo->getTypeLoc().getBeginLoc(),
9887 diag::warn_cxx14_compat_class_template_argument_deduction)
9888 << TSInfo->getTypeLoc().getSourceRange() << 0;
9889 return SubstAutoType(TSInfo->getType(), Context.DependentTy);
9890 }
9891
9892 // FIXME: Perform "exact type" matching first, per CWG discussion?
9893 // Or implement this via an implied 'T(T) -> T' deduction guide?
9894
9895 // FIXME: Do we need/want a std::initializer_list<T> special case?
9896
9897 // Look up deduction guides, including those synthesized from constructors.
9898 //
9899 // C++1z [over.match.class.deduct]p1:
9900 // A set of functions and function templates is formed comprising:
9901 // - For each constructor of the class template designated by the
9902 // template-name, a function template [...]
9903 // - For each deduction-guide, a function or function template [...]
9904 DeclarationNameInfo NameInfo(
9905 Context.DeclarationNames.getCXXDeductionGuideName(Template),
9906 TSInfo->getTypeLoc().getEndLoc());
9907 LookupResult Guides(*this, NameInfo, LookupOrdinaryName);
9908 LookupQualifiedName(Guides, Template->getDeclContext());
9909
9910 // FIXME: Do not diagnose inaccessible deduction guides. The standard isn't
9911 // clear on this, but they're not found by name so access does not apply.
9912 Guides.suppressDiagnostics();
9913
9914 // Figure out if this is list-initialization.
9915 InitListExpr *ListInit =
9916 (Inits.size() == 1 && Kind.getKind() != InitializationKind::IK_Direct)
9917 ? dyn_cast<InitListExpr>(Inits[0])
9918 : nullptr;
9919
9920 // C++1z [over.match.class.deduct]p1:
9921 // Initialization and overload resolution are performed as described in
9922 // [dcl.init] and [over.match.ctor], [over.match.copy], or [over.match.list]
9923 // (as appropriate for the type of initialization performed) for an object
9924 // of a hypothetical class type, where the selected functions and function
9925 // templates are considered to be the constructors of that class type
9926 //
9927 // Since we know we're initializing a class type of a type unrelated to that
9928 // of the initializer, this reduces to something fairly reasonable.
9929 OverloadCandidateSet Candidates(Kind.getLocation(),
9930 OverloadCandidateSet::CSK_Normal);
9931 OverloadCandidateSet::iterator Best;
9932
9933 bool HasAnyDeductionGuide = false;
9934 bool AllowExplicit = !Kind.isCopyInit() || ListInit;
9935
9936 auto tryToResolveOverload =
9937 [&](bool OnlyListConstructors) -> OverloadingResult {
9938 Candidates.clear(OverloadCandidateSet::CSK_Normal);
9939 HasAnyDeductionGuide = false;
9940
9941 for (auto I = Guides.begin(), E = Guides.end(); I != E; ++I) {
9942 NamedDecl *D = (*I)->getUnderlyingDecl();
9943 if (D->isInvalidDecl())
9944 continue;
9945
9946 auto *TD = dyn_cast<FunctionTemplateDecl>(D);
9947 auto *GD = dyn_cast_or_null<CXXDeductionGuideDecl>(
9948 TD ? TD->getTemplatedDecl() : dyn_cast<FunctionDecl>(D));
9949 if (!GD)
9950 continue;
9951
9952 if (!GD->isImplicit())
9953 HasAnyDeductionGuide = true;
9954
9955 // C++ [over.match.ctor]p1: (non-list copy-initialization from non-class)
9956 // For copy-initialization, the candidate functions are all the
9957 // converting constructors (12.3.1) of that class.
9958 // C++ [over.match.copy]p1: (non-list copy-initialization from class)
9959 // The converting constructors of T are candidate functions.
9960 if (!AllowExplicit) {
9961 // Overload resolution checks whether the deduction guide is declared
9962 // explicit for us.
9963
9964 // When looking for a converting constructor, deduction guides that
9965 // could never be called with one argument are not interesting to
9966 // check or note.
9967 if (GD->getMinRequiredArguments() > 1 ||
9968 (GD->getNumParams() == 0 && !GD->isVariadic()))
9969 continue;
9970 }
9971
9972 // C++ [over.match.list]p1.1: (first phase list initialization)
9973 // Initially, the candidate functions are the initializer-list
9974 // constructors of the class T
9975 if (OnlyListConstructors && !isInitListConstructor(GD))
9976 continue;
9977
9978 // C++ [over.match.list]p1.2: (second phase list initialization)
9979 // the candidate functions are all the constructors of the class T
9980 // C++ [over.match.ctor]p1: (all other cases)
9981 // the candidate functions are all the constructors of the class of
9982 // the object being initialized
9983
9984 // C++ [over.best.ics]p4:
9985 // When [...] the constructor [...] is a candidate by
9986 // - [over.match.copy] (in all cases)
9987 // FIXME: The "second phase of [over.match.list] case can also
9988 // theoretically happen here, but it's not clear whether we can
9989 // ever have a parameter of the right type.
9990 bool SuppressUserConversions = Kind.isCopyInit();
9991
9992 if (TD)
9993 AddTemplateOverloadCandidate(TD, I.getPair(), /*ExplicitArgs*/ nullptr,
9994 Inits, Candidates, SuppressUserConversions,
9995 /*PartialOverloading*/ false,
9996 AllowExplicit);
9997 else
9998 AddOverloadCandidate(GD, I.getPair(), Inits, Candidates,
9999 SuppressUserConversions,
10000 /*PartialOverloading*/ false, AllowExplicit);
10001 }
10002 return Candidates.BestViableFunction(*this, Kind.getLocation(), Best);
10003 };
10004
10005 OverloadingResult Result = OR_No_Viable_Function;
10006
10007 // C++11 [over.match.list]p1, per DR1467: for list-initialization, first
10008 // try initializer-list constructors.
10009 if (ListInit) {
10010 bool TryListConstructors = true;
10011
10012 // Try list constructors unless the list is empty and the class has one or
10013 // more default constructors, in which case those constructors win.
10014 if (!ListInit->getNumInits()) {
10015 for (NamedDecl *D : Guides) {
10016 auto *FD = dyn_cast<FunctionDecl>(D->getUnderlyingDecl());
10017 if (FD && FD->getMinRequiredArguments() == 0) {
10018 TryListConstructors = false;
10019 break;
10020 }
10021 }
10022 } else if (ListInit->getNumInits() == 1) {
10023 // C++ [over.match.class.deduct]:
10024 // As an exception, the first phase in [over.match.list] (considering
10025 // initializer-list constructors) is omitted if the initializer list
10026 // consists of a single expression of type cv U, where U is a
10027 // specialization of C or a class derived from a specialization of C.
10028 Expr *E = ListInit->getInit(0);
10029 auto *RD = E->getType()->getAsCXXRecordDecl();
10030 if (!isa<InitListExpr>(E) && RD &&
10031 isCompleteType(Kind.getLocation(), E->getType()) &&
10032 isOrIsDerivedFromSpecializationOf(RD, Template))
10033 TryListConstructors = false;
10034 }
10035
10036 if (TryListConstructors)
10037 Result = tryToResolveOverload(/*OnlyListConstructor*/true);
10038 // Then unwrap the initializer list and try again considering all
10039 // constructors.
10040 Inits = MultiExprArg(ListInit->getInits(), ListInit->getNumInits());
10041 }
10042
10043 // If list-initialization fails, or if we're doing any other kind of
10044 // initialization, we (eventually) consider constructors.
10045 if (Result == OR_No_Viable_Function)
10046 Result = tryToResolveOverload(/*OnlyListConstructor*/false);
10047
10048 switch (Result) {
10049 case OR_Ambiguous:
10050 // FIXME: For list-initialization candidates, it'd usually be better to
10051 // list why they were not viable when given the initializer list itself as
10052 // an argument.
10053 Candidates.NoteCandidates(
10054 PartialDiagnosticAt(
10055 Kind.getLocation(),
10056 PDiag(diag::err_deduced_class_template_ctor_ambiguous)
10057 << TemplateName),
10058 *this, OCD_AmbiguousCandidates, Inits);
10059 return QualType();
10060
10061 case OR_No_Viable_Function: {
10062 CXXRecordDecl *Primary =
10063 cast<ClassTemplateDecl>(Template)->getTemplatedDecl();
10064 bool Complete =
10065 isCompleteType(Kind.getLocation(), Context.getTypeDeclType(Primary));
10066 Candidates.NoteCandidates(
10067 PartialDiagnosticAt(
10068 Kind.getLocation(),
10069 PDiag(Complete ? diag::err_deduced_class_template_ctor_no_viable
10070 : diag::err_deduced_class_template_incomplete)
10071 << TemplateName << !Guides.empty()),
10072 *this, OCD_AllCandidates, Inits);
10073 return QualType();
10074 }
10075
10076 case OR_Deleted: {
10077 Diag(Kind.getLocation(), diag::err_deduced_class_template_deleted)
10078 << TemplateName;
10079 NoteDeletedFunction(Best->Function);
10080 return QualType();
10081 }
10082
10083 case OR_Success:
10084 // C++ [over.match.list]p1:
10085 // In copy-list-initialization, if an explicit constructor is chosen, the
10086 // initialization is ill-formed.
10087 if (Kind.isCopyInit() && ListInit &&
10088 cast<CXXDeductionGuideDecl>(Best->Function)->isExplicit()) {
10089 bool IsDeductionGuide = !Best->Function->isImplicit();
10090 Diag(Kind.getLocation(), diag::err_deduced_class_template_explicit)
10091 << TemplateName << IsDeductionGuide;
10092 Diag(Best->Function->getLocation(),
10093 diag::note_explicit_ctor_deduction_guide_here)
10094 << IsDeductionGuide;
10095 return QualType();
10096 }
10097
10098 // Make sure we didn't select an unusable deduction guide, and mark it
10099 // as referenced.
10100 DiagnoseUseOfDecl(Best->Function, Kind.getLocation());
10101 MarkFunctionReferenced(Kind.getLocation(), Best->Function);
10102 break;
10103 }
10104
10105 // C++ [dcl.type.class.deduct]p1:
10106 // The placeholder is replaced by the return type of the function selected
10107 // by overload resolution for class template deduction.
10108 QualType DeducedType =
10109 SubstAutoType(TSInfo->getType(), Best->Function->getReturnType());
10110 Diag(TSInfo->getTypeLoc().getBeginLoc(),
10111 diag::warn_cxx14_compat_class_template_argument_deduction)
10112 << TSInfo->getTypeLoc().getSourceRange() << 1 << DeducedType;
10113
10114 // Warn if CTAD was used on a type that does not have any user-defined
10115 // deduction guides.
10116 if (!HasAnyDeductionGuide) {
10117 Diag(TSInfo->getTypeLoc().getBeginLoc(),
10118 diag::warn_ctad_maybe_unsupported)
10119 << TemplateName;
10120 Diag(Template->getLocation(), diag::note_suppress_ctad_maybe_unsupported);
10121 }
10122
10123 return DeducedType;
10124 }
10125