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SemaExprCXX.cpp
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1 //===--- SemaExprCXX.cpp - Semantic Analysis for Expressions --------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 ///
10 /// \file
11 /// \brief Implements semantic analysis for C++ expressions.
12 ///
13 //===----------------------------------------------------------------------===//
14 
16 #include "TreeTransform.h"
17 #include "TypeLocBuilder.h"
18 #include "clang/AST/ASTContext.h"
19 #include "clang/AST/ASTLambda.h"
21 #include "clang/AST/CharUnits.h"
22 #include "clang/AST/DeclObjC.h"
23 #include "clang/AST/ExprCXX.h"
24 #include "clang/AST/ExprObjC.h"
26 #include "clang/AST/TypeLoc.h"
29 #include "clang/Basic/TargetInfo.h"
30 #include "clang/Lex/Preprocessor.h"
31 #include "clang/Sema/DeclSpec.h"
33 #include "clang/Sema/Lookup.h"
35 #include "clang/Sema/Scope.h"
36 #include "clang/Sema/ScopeInfo.h"
37 #include "clang/Sema/SemaLambda.h"
39 #include "llvm/ADT/APInt.h"
40 #include "llvm/ADT/STLExtras.h"
41 #include "llvm/Support/ErrorHandling.h"
42 using namespace clang;
43 using namespace sema;
44 
45 /// \brief Handle the result of the special case name lookup for inheriting
46 /// constructor declarations. 'NS::X::X' and 'NS::X<...>::X' are treated as
47 /// constructor names in member using declarations, even if 'X' is not the
48 /// name of the corresponding type.
50  SourceLocation NameLoc,
51  IdentifierInfo &Name) {
52  NestedNameSpecifier *NNS = SS.getScopeRep();
53 
54  // Convert the nested-name-specifier into a type.
55  QualType Type;
56  switch (NNS->getKind()) {
59  Type = QualType(NNS->getAsType(), 0);
60  break;
61 
63  // Strip off the last layer of the nested-name-specifier and build a
64  // typename type for it.
65  assert(NNS->getAsIdentifier() == &Name && "not a constructor name");
66  Type = Context.getDependentNameType(ETK_None, NNS->getPrefix(),
67  NNS->getAsIdentifier());
68  break;
69 
74  llvm_unreachable("Nested name specifier is not a type for inheriting ctor");
75  }
76 
77  // This reference to the type is located entirely at the location of the
78  // final identifier in the qualified-id.
79  return CreateParsedType(Type,
80  Context.getTrivialTypeSourceInfo(Type, NameLoc));
81 }
82 
84  IdentifierInfo &II,
85  SourceLocation NameLoc,
86  Scope *S, CXXScopeSpec &SS,
87  ParsedType ObjectTypePtr,
88  bool EnteringContext) {
89  // Determine where to perform name lookup.
90 
91  // FIXME: This area of the standard is very messy, and the current
92  // wording is rather unclear about which scopes we search for the
93  // destructor name; see core issues 399 and 555. Issue 399 in
94  // particular shows where the current description of destructor name
95  // lookup is completely out of line with existing practice, e.g.,
96  // this appears to be ill-formed:
97  //
98  // namespace N {
99  // template <typename T> struct S {
100  // ~S();
101  // };
102  // }
103  //
104  // void f(N::S<int>* s) {
105  // s->N::S<int>::~S();
106  // }
107  //
108  // See also PR6358 and PR6359.
109  // For this reason, we're currently only doing the C++03 version of this
110  // code; the C++0x version has to wait until we get a proper spec.
111  QualType SearchType;
112  DeclContext *LookupCtx = nullptr;
113  bool isDependent = false;
114  bool LookInScope = false;
115 
116  if (SS.isInvalid())
117  return nullptr;
118 
119  // If we have an object type, it's because we are in a
120  // pseudo-destructor-expression or a member access expression, and
121  // we know what type we're looking for.
122  if (ObjectTypePtr)
123  SearchType = GetTypeFromParser(ObjectTypePtr);
124 
125  if (SS.isSet()) {
126  NestedNameSpecifier *NNS = SS.getScopeRep();
127 
128  bool AlreadySearched = false;
129  bool LookAtPrefix = true;
130  // C++11 [basic.lookup.qual]p6:
131  // If a pseudo-destructor-name (5.2.4) contains a nested-name-specifier,
132  // the type-names are looked up as types in the scope designated by the
133  // nested-name-specifier. Similarly, in a qualified-id of the form:
134  //
135  // nested-name-specifier[opt] class-name :: ~ class-name
136  //
137  // the second class-name is looked up in the same scope as the first.
138  //
139  // Here, we determine whether the code below is permitted to look at the
140  // prefix of the nested-name-specifier.
141  DeclContext *DC = computeDeclContext(SS, EnteringContext);
142  if (DC && DC->isFileContext()) {
143  AlreadySearched = true;
144  LookupCtx = DC;
145  isDependent = false;
146  } else if (DC && isa<CXXRecordDecl>(DC)) {
147  LookAtPrefix = false;
148  LookInScope = true;
149  }
150 
151  // The second case from the C++03 rules quoted further above.
152  NestedNameSpecifier *Prefix = nullptr;
153  if (AlreadySearched) {
154  // Nothing left to do.
155  } else if (LookAtPrefix && (Prefix = NNS->getPrefix())) {
156  CXXScopeSpec PrefixSS;
157  PrefixSS.Adopt(NestedNameSpecifierLoc(Prefix, SS.location_data()));
158  LookupCtx = computeDeclContext(PrefixSS, EnteringContext);
159  isDependent = isDependentScopeSpecifier(PrefixSS);
160  } else if (ObjectTypePtr) {
161  LookupCtx = computeDeclContext(SearchType);
162  isDependent = SearchType->isDependentType();
163  } else {
164  LookupCtx = computeDeclContext(SS, EnteringContext);
165  isDependent = LookupCtx && LookupCtx->isDependentContext();
166  }
167  } else if (ObjectTypePtr) {
168  // C++ [basic.lookup.classref]p3:
169  // If the unqualified-id is ~type-name, the type-name is looked up
170  // in the context of the entire postfix-expression. If the type T
171  // of the object expression is of a class type C, the type-name is
172  // also looked up in the scope of class C. At least one of the
173  // lookups shall find a name that refers to (possibly
174  // cv-qualified) T.
175  LookupCtx = computeDeclContext(SearchType);
176  isDependent = SearchType->isDependentType();
177  assert((isDependent || !SearchType->isIncompleteType()) &&
178  "Caller should have completed object type");
179 
180  LookInScope = true;
181  } else {
182  // Perform lookup into the current scope (only).
183  LookInScope = true;
184  }
185 
186  TypeDecl *NonMatchingTypeDecl = nullptr;
187  LookupResult Found(*this, &II, NameLoc, LookupOrdinaryName);
188  for (unsigned Step = 0; Step != 2; ++Step) {
189  // Look for the name first in the computed lookup context (if we
190  // have one) and, if that fails to find a match, in the scope (if
191  // we're allowed to look there).
192  Found.clear();
193  if (Step == 0 && LookupCtx) {
194  if (RequireCompleteDeclContext(SS, LookupCtx))
195  return nullptr;
196  LookupQualifiedName(Found, LookupCtx);
197  } else if (Step == 1 && LookInScope && S) {
198  LookupName(Found, S);
199  } else {
200  continue;
201  }
202 
203  // FIXME: Should we be suppressing ambiguities here?
204  if (Found.isAmbiguous())
205  return nullptr;
206 
207  if (TypeDecl *Type = Found.getAsSingle<TypeDecl>()) {
208  QualType T = Context.getTypeDeclType(Type);
209  MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
210 
211  if (SearchType.isNull() || SearchType->isDependentType() ||
212  Context.hasSameUnqualifiedType(T, SearchType)) {
213  // We found our type!
214 
215  return CreateParsedType(T,
216  Context.getTrivialTypeSourceInfo(T, NameLoc));
217  }
218 
219  if (!SearchType.isNull())
220  NonMatchingTypeDecl = Type;
221  }
222 
223  // If the name that we found is a class template name, and it is
224  // the same name as the template name in the last part of the
225  // nested-name-specifier (if present) or the object type, then
226  // this is the destructor for that class.
227  // FIXME: This is a workaround until we get real drafting for core
228  // issue 399, for which there isn't even an obvious direction.
229  if (ClassTemplateDecl *Template = Found.getAsSingle<ClassTemplateDecl>()) {
230  QualType MemberOfType;
231  if (SS.isSet()) {
232  if (DeclContext *Ctx = computeDeclContext(SS, EnteringContext)) {
233  // Figure out the type of the context, if it has one.
234  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Ctx))
235  MemberOfType = Context.getTypeDeclType(Record);
236  }
237  }
238  if (MemberOfType.isNull())
239  MemberOfType = SearchType;
240 
241  if (MemberOfType.isNull())
242  continue;
243 
244  // We're referring into a class template specialization. If the
245  // class template we found is the same as the template being
246  // specialized, we found what we are looking for.
247  if (const RecordType *Record = MemberOfType->getAs<RecordType>()) {
249  = dyn_cast<ClassTemplateSpecializationDecl>(Record->getDecl())) {
250  if (Spec->getSpecializedTemplate()->getCanonicalDecl() ==
251  Template->getCanonicalDecl())
252  return CreateParsedType(
253  MemberOfType,
254  Context.getTrivialTypeSourceInfo(MemberOfType, NameLoc));
255  }
256 
257  continue;
258  }
259 
260  // We're referring to an unresolved class template
261  // specialization. Determine whether we class template we found
262  // is the same as the template being specialized or, if we don't
263  // know which template is being specialized, that it at least
264  // has the same name.
265  if (const TemplateSpecializationType *SpecType
266  = MemberOfType->getAs<TemplateSpecializationType>()) {
267  TemplateName SpecName = SpecType->getTemplateName();
268 
269  // The class template we found is the same template being
270  // specialized.
271  if (TemplateDecl *SpecTemplate = SpecName.getAsTemplateDecl()) {
272  if (SpecTemplate->getCanonicalDecl() == Template->getCanonicalDecl())
273  return CreateParsedType(
274  MemberOfType,
275  Context.getTrivialTypeSourceInfo(MemberOfType, NameLoc));
276 
277  continue;
278  }
279 
280  // The class template we found has the same name as the
281  // (dependent) template name being specialized.
282  if (DependentTemplateName *DepTemplate
283  = SpecName.getAsDependentTemplateName()) {
284  if (DepTemplate->isIdentifier() &&
285  DepTemplate->getIdentifier() == Template->getIdentifier())
286  return CreateParsedType(
287  MemberOfType,
288  Context.getTrivialTypeSourceInfo(MemberOfType, NameLoc));
289 
290  continue;
291  }
292  }
293  }
294  }
295 
296  if (isDependent) {
297  // We didn't find our type, but that's okay: it's dependent
298  // anyway.
299 
300  // FIXME: What if we have no nested-name-specifier?
301  QualType T = CheckTypenameType(ETK_None, SourceLocation(),
302  SS.getWithLocInContext(Context),
303  II, NameLoc);
304  return ParsedType::make(T);
305  }
306 
307  if (NonMatchingTypeDecl) {
308  QualType T = Context.getTypeDeclType(NonMatchingTypeDecl);
309  Diag(NameLoc, diag::err_destructor_expr_type_mismatch)
310  << T << SearchType;
311  Diag(NonMatchingTypeDecl->getLocation(), diag::note_destructor_type_here)
312  << T;
313  } else if (ObjectTypePtr)
314  Diag(NameLoc, diag::err_ident_in_dtor_not_a_type)
315  << &II;
316  else {
317  SemaDiagnosticBuilder DtorDiag = Diag(NameLoc,
318  diag::err_destructor_class_name);
319  if (S) {
320  const DeclContext *Ctx = S->getEntity();
321  if (const CXXRecordDecl *Class = dyn_cast_or_null<CXXRecordDecl>(Ctx))
322  DtorDiag << FixItHint::CreateReplacement(SourceRange(NameLoc),
323  Class->getNameAsString());
324  }
325  }
326 
327  return nullptr;
328 }
329 
331  ParsedType ObjectType) {
333  return nullptr;
334 
336  Diag(DS.getTypeSpecTypeLoc(), diag::err_decltype_auto_invalid);
337  return nullptr;
338  }
339 
340  assert(DS.getTypeSpecType() == DeclSpec::TST_decltype &&
341  "unexpected type in getDestructorType");
342  QualType T = BuildDecltypeType(DS.getRepAsExpr(), DS.getTypeSpecTypeLoc());
343 
344  // If we know the type of the object, check that the correct destructor
345  // type was named now; we can give better diagnostics this way.
346  QualType SearchType = GetTypeFromParser(ObjectType);
347  if (!SearchType.isNull() && !SearchType->isDependentType() &&
348  !Context.hasSameUnqualifiedType(T, SearchType)) {
349  Diag(DS.getTypeSpecTypeLoc(), diag::err_destructor_expr_type_mismatch)
350  << T << SearchType;
351  return nullptr;
352  }
353 
354  return ParsedType::make(T);
355 }
356 
358  const UnqualifiedId &Name) {
360 
361  if (!SS.isValid())
362  return false;
363 
364  switch (SS.getScopeRep()->getKind()) {
368  // Per C++11 [over.literal]p2, literal operators can only be declared at
369  // namespace scope. Therefore, this unqualified-id cannot name anything.
370  // Reject it early, because we have no AST representation for this in the
371  // case where the scope is dependent.
372  Diag(Name.getLocStart(), diag::err_literal_operator_id_outside_namespace)
373  << SS.getScopeRep();
374  return true;
375 
380  return false;
381  }
382 
383  llvm_unreachable("unknown nested name specifier kind");
384 }
385 
386 /// \brief Build a C++ typeid expression with a type operand.
388  SourceLocation TypeidLoc,
389  TypeSourceInfo *Operand,
390  SourceLocation RParenLoc) {
391  // C++ [expr.typeid]p4:
392  // The top-level cv-qualifiers of the lvalue expression or the type-id
393  // that is the operand of typeid are always ignored.
394  // If the type of the type-id is a class type or a reference to a class
395  // type, the class shall be completely-defined.
396  Qualifiers Quals;
397  QualType T
398  = Context.getUnqualifiedArrayType(Operand->getType().getNonReferenceType(),
399  Quals);
400  if (T->getAs<RecordType>() &&
401  RequireCompleteType(TypeidLoc, T, diag::err_incomplete_typeid))
402  return ExprError();
403 
404  if (T->isVariablyModifiedType())
405  return ExprError(Diag(TypeidLoc, diag::err_variably_modified_typeid) << T);
406 
407  return new (Context) CXXTypeidExpr(TypeInfoType.withConst(), Operand,
408  SourceRange(TypeidLoc, RParenLoc));
409 }
410 
411 /// \brief Build a C++ typeid expression with an expression operand.
413  SourceLocation TypeidLoc,
414  Expr *E,
415  SourceLocation RParenLoc) {
416  bool WasEvaluated = false;
417  if (E && !E->isTypeDependent()) {
418  if (E->getType()->isPlaceholderType()) {
419  ExprResult result = CheckPlaceholderExpr(E);
420  if (result.isInvalid()) return ExprError();
421  E = result.get();
422  }
423 
424  QualType T = E->getType();
425  if (const RecordType *RecordT = T->getAs<RecordType>()) {
426  CXXRecordDecl *RecordD = cast<CXXRecordDecl>(RecordT->getDecl());
427  // C++ [expr.typeid]p3:
428  // [...] If the type of the expression is a class type, the class
429  // shall be completely-defined.
430  if (RequireCompleteType(TypeidLoc, T, diag::err_incomplete_typeid))
431  return ExprError();
432 
433  // C++ [expr.typeid]p3:
434  // When typeid is applied to an expression other than an glvalue of a
435  // polymorphic class type [...] [the] expression is an unevaluated
436  // operand. [...]
437  if (RecordD->isPolymorphic() && E->isGLValue()) {
438  // The subexpression is potentially evaluated; switch the context
439  // and recheck the subexpression.
440  ExprResult Result = TransformToPotentiallyEvaluated(E);
441  if (Result.isInvalid()) return ExprError();
442  E = Result.get();
443 
444  // We require a vtable to query the type at run time.
445  MarkVTableUsed(TypeidLoc, RecordD);
446  WasEvaluated = true;
447  }
448  }
449 
450  // C++ [expr.typeid]p4:
451  // [...] If the type of the type-id is a reference to a possibly
452  // cv-qualified type, the result of the typeid expression refers to a
453  // std::type_info object representing the cv-unqualified referenced
454  // type.
455  Qualifiers Quals;
456  QualType UnqualT = Context.getUnqualifiedArrayType(T, Quals);
457  if (!Context.hasSameType(T, UnqualT)) {
458  T = UnqualT;
459  E = ImpCastExprToType(E, UnqualT, CK_NoOp, E->getValueKind()).get();
460  }
461  }
462 
463  if (E->getType()->isVariablyModifiedType())
464  return ExprError(Diag(TypeidLoc, diag::err_variably_modified_typeid)
465  << E->getType());
466  else if (!inTemplateInstantiation() &&
467  E->HasSideEffects(Context, WasEvaluated)) {
468  // The expression operand for typeid is in an unevaluated expression
469  // context, so side effects could result in unintended consequences.
470  Diag(E->getExprLoc(), WasEvaluated
471  ? diag::warn_side_effects_typeid
472  : diag::warn_side_effects_unevaluated_context);
473  }
474 
475  return new (Context) CXXTypeidExpr(TypeInfoType.withConst(), E,
476  SourceRange(TypeidLoc, RParenLoc));
477 }
478 
479 /// ActOnCXXTypeidOfType - Parse typeid( type-id ) or typeid (expression);
482  bool isType, void *TyOrExpr, SourceLocation RParenLoc) {
483  // Find the std::type_info type.
484  if (!getStdNamespace())
485  return ExprError(Diag(OpLoc, diag::err_need_header_before_typeid));
486 
487  if (!CXXTypeInfoDecl) {
488  IdentifierInfo *TypeInfoII = &PP.getIdentifierTable().get("type_info");
489  LookupResult R(*this, TypeInfoII, SourceLocation(), LookupTagName);
490  LookupQualifiedName(R, getStdNamespace());
491  CXXTypeInfoDecl = R.getAsSingle<RecordDecl>();
492  // Microsoft's typeinfo doesn't have type_info in std but in the global
493  // namespace if _HAS_EXCEPTIONS is defined to 0. See PR13153.
494  if (!CXXTypeInfoDecl && LangOpts.MSVCCompat) {
495  LookupQualifiedName(R, Context.getTranslationUnitDecl());
496  CXXTypeInfoDecl = R.getAsSingle<RecordDecl>();
497  }
498  if (!CXXTypeInfoDecl)
499  return ExprError(Diag(OpLoc, diag::err_need_header_before_typeid));
500  }
501 
502  if (!getLangOpts().RTTI) {
503  return ExprError(Diag(OpLoc, diag::err_no_typeid_with_fno_rtti));
504  }
505 
506  QualType TypeInfoType = Context.getTypeDeclType(CXXTypeInfoDecl);
507 
508  if (isType) {
509  // The operand is a type; handle it as such.
510  TypeSourceInfo *TInfo = nullptr;
511  QualType T = GetTypeFromParser(ParsedType::getFromOpaquePtr(TyOrExpr),
512  &TInfo);
513  if (T.isNull())
514  return ExprError();
515 
516  if (!TInfo)
517  TInfo = Context.getTrivialTypeSourceInfo(T, OpLoc);
518 
519  return BuildCXXTypeId(TypeInfoType, OpLoc, TInfo, RParenLoc);
520  }
521 
522  // The operand is an expression.
523  return BuildCXXTypeId(TypeInfoType, OpLoc, (Expr*)TyOrExpr, RParenLoc);
524 }
525 
526 /// Grabs __declspec(uuid()) off a type, or returns 0 if we cannot resolve to
527 /// a single GUID.
528 static void
531  // Optionally remove one level of pointer, reference or array indirection.
532  const Type *Ty = QT.getTypePtr();
533  if (QT->isPointerType() || QT->isReferenceType())
534  Ty = QT->getPointeeType().getTypePtr();
535  else if (QT->isArrayType())
536  Ty = Ty->getBaseElementTypeUnsafe();
537 
538  const auto *TD = Ty->getAsTagDecl();
539  if (!TD)
540  return;
541 
542  if (const auto *Uuid = TD->getMostRecentDecl()->getAttr<UuidAttr>()) {
543  UuidAttrs.insert(Uuid);
544  return;
545  }
546 
547  // __uuidof can grab UUIDs from template arguments.
548  if (const auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(TD)) {
549  const TemplateArgumentList &TAL = CTSD->getTemplateArgs();
550  for (const TemplateArgument &TA : TAL.asArray()) {
551  const UuidAttr *UuidForTA = nullptr;
552  if (TA.getKind() == TemplateArgument::Type)
553  getUuidAttrOfType(SemaRef, TA.getAsType(), UuidAttrs);
554  else if (TA.getKind() == TemplateArgument::Declaration)
555  getUuidAttrOfType(SemaRef, TA.getAsDecl()->getType(), UuidAttrs);
556 
557  if (UuidForTA)
558  UuidAttrs.insert(UuidForTA);
559  }
560  }
561 }
562 
563 /// \brief Build a Microsoft __uuidof expression with a type operand.
565  SourceLocation TypeidLoc,
566  TypeSourceInfo *Operand,
567  SourceLocation RParenLoc) {
568  StringRef UuidStr;
569  if (!Operand->getType()->isDependentType()) {
571  getUuidAttrOfType(*this, Operand->getType(), UuidAttrs);
572  if (UuidAttrs.empty())
573  return ExprError(Diag(TypeidLoc, diag::err_uuidof_without_guid));
574  if (UuidAttrs.size() > 1)
575  return ExprError(Diag(TypeidLoc, diag::err_uuidof_with_multiple_guids));
576  UuidStr = UuidAttrs.back()->getGuid();
577  }
578 
579  return new (Context) CXXUuidofExpr(TypeInfoType.withConst(), Operand, UuidStr,
580  SourceRange(TypeidLoc, RParenLoc));
581 }
582 
583 /// \brief Build a Microsoft __uuidof expression with an expression operand.
585  SourceLocation TypeidLoc,
586  Expr *E,
587  SourceLocation RParenLoc) {
588  StringRef UuidStr;
589  if (!E->getType()->isDependentType()) {
591  UuidStr = "00000000-0000-0000-0000-000000000000";
592  } else {
594  getUuidAttrOfType(*this, E->getType(), UuidAttrs);
595  if (UuidAttrs.empty())
596  return ExprError(Diag(TypeidLoc, diag::err_uuidof_without_guid));
597  if (UuidAttrs.size() > 1)
598  return ExprError(Diag(TypeidLoc, diag::err_uuidof_with_multiple_guids));
599  UuidStr = UuidAttrs.back()->getGuid();
600  }
601  }
602 
603  return new (Context) CXXUuidofExpr(TypeInfoType.withConst(), E, UuidStr,
604  SourceRange(TypeidLoc, RParenLoc));
605 }
606 
607 /// ActOnCXXUuidof - Parse __uuidof( type-id ) or __uuidof (expression);
610  bool isType, void *TyOrExpr, SourceLocation RParenLoc) {
611  // If MSVCGuidDecl has not been cached, do the lookup.
612  if (!MSVCGuidDecl) {
613  IdentifierInfo *GuidII = &PP.getIdentifierTable().get("_GUID");
614  LookupResult R(*this, GuidII, SourceLocation(), LookupTagName);
615  LookupQualifiedName(R, Context.getTranslationUnitDecl());
616  MSVCGuidDecl = R.getAsSingle<RecordDecl>();
617  if (!MSVCGuidDecl)
618  return ExprError(Diag(OpLoc, diag::err_need_header_before_ms_uuidof));
619  }
620 
621  QualType GuidType = Context.getTypeDeclType(MSVCGuidDecl);
622 
623  if (isType) {
624  // The operand is a type; handle it as such.
625  TypeSourceInfo *TInfo = nullptr;
626  QualType T = GetTypeFromParser(ParsedType::getFromOpaquePtr(TyOrExpr),
627  &TInfo);
628  if (T.isNull())
629  return ExprError();
630 
631  if (!TInfo)
632  TInfo = Context.getTrivialTypeSourceInfo(T, OpLoc);
633 
634  return BuildCXXUuidof(GuidType, OpLoc, TInfo, RParenLoc);
635  }
636 
637  // The operand is an expression.
638  return BuildCXXUuidof(GuidType, OpLoc, (Expr*)TyOrExpr, RParenLoc);
639 }
640 
641 /// ActOnCXXBoolLiteral - Parse {true,false} literals.
644  assert((Kind == tok::kw_true || Kind == tok::kw_false) &&
645  "Unknown C++ Boolean value!");
646  return new (Context)
647  CXXBoolLiteralExpr(Kind == tok::kw_true, Context.BoolTy, OpLoc);
648 }
649 
650 /// ActOnCXXNullPtrLiteral - Parse 'nullptr'.
653  return new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc);
654 }
655 
656 /// ActOnCXXThrow - Parse throw expressions.
659  bool IsThrownVarInScope = false;
660  if (Ex) {
661  // C++0x [class.copymove]p31:
662  // When certain criteria are met, an implementation is allowed to omit the
663  // copy/move construction of a class object [...]
664  //
665  // - in a throw-expression, when the operand is the name of a
666  // non-volatile automatic object (other than a function or catch-
667  // clause parameter) whose scope does not extend beyond the end of the
668  // innermost enclosing try-block (if there is one), the copy/move
669  // operation from the operand to the exception object (15.1) can be
670  // omitted by constructing the automatic object directly into the
671  // exception object
672  if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Ex->IgnoreParens()))
673  if (VarDecl *Var = dyn_cast<VarDecl>(DRE->getDecl())) {
674  if (Var->hasLocalStorage() && !Var->getType().isVolatileQualified()) {
675  for( ; S; S = S->getParent()) {
676  if (S->isDeclScope(Var)) {
677  IsThrownVarInScope = true;
678  break;
679  }
680 
681  if (S->getFlags() &
685  break;
686  }
687  }
688  }
689  }
690 
691  return BuildCXXThrow(OpLoc, Ex, IsThrownVarInScope);
692 }
693 
695  bool IsThrownVarInScope) {
696  // Don't report an error if 'throw' is used in system headers.
697  if (!getLangOpts().CXXExceptions &&
698  !getSourceManager().isInSystemHeader(OpLoc))
699  Diag(OpLoc, diag::err_exceptions_disabled) << "throw";
700 
701  // Exceptions aren't allowed in CUDA device code.
702  if (getLangOpts().CUDA)
703  CUDADiagIfDeviceCode(OpLoc, diag::err_cuda_device_exceptions)
704  << "throw" << CurrentCUDATarget();
705 
706  if (getCurScope() && getCurScope()->isOpenMPSimdDirectiveScope())
707  Diag(OpLoc, diag::err_omp_simd_region_cannot_use_stmt) << "throw";
708 
709  if (Ex && !Ex->isTypeDependent()) {
710  QualType ExceptionObjectTy = Context.getExceptionObjectType(Ex->getType());
711  if (CheckCXXThrowOperand(OpLoc, ExceptionObjectTy, Ex))
712  return ExprError();
713 
714  // Initialize the exception result. This implicitly weeds out
715  // abstract types or types with inaccessible copy constructors.
716 
717  // C++0x [class.copymove]p31:
718  // When certain criteria are met, an implementation is allowed to omit the
719  // copy/move construction of a class object [...]
720  //
721  // - in a throw-expression, when the operand is the name of a
722  // non-volatile automatic object (other than a function or
723  // catch-clause
724  // parameter) whose scope does not extend beyond the end of the
725  // innermost enclosing try-block (if there is one), the copy/move
726  // operation from the operand to the exception object (15.1) can be
727  // omitted by constructing the automatic object directly into the
728  // exception object
729  const VarDecl *NRVOVariable = nullptr;
730  if (IsThrownVarInScope)
731  NRVOVariable = getCopyElisionCandidate(QualType(), Ex, false);
732 
734  OpLoc, ExceptionObjectTy,
735  /*NRVO=*/NRVOVariable != nullptr);
736  ExprResult Res = PerformMoveOrCopyInitialization(
737  Entity, NRVOVariable, QualType(), Ex, IsThrownVarInScope);
738  if (Res.isInvalid())
739  return ExprError();
740  Ex = Res.get();
741  }
742 
743  return new (Context)
744  CXXThrowExpr(Ex, Context.VoidTy, OpLoc, IsThrownVarInScope);
745 }
746 
747 static void
749  llvm::DenseMap<CXXRecordDecl *, unsigned> &SubobjectsSeen,
750  llvm::SmallPtrSetImpl<CXXRecordDecl *> &VBases,
751  llvm::SetVector<CXXRecordDecl *> &PublicSubobjectsSeen,
752  bool ParentIsPublic) {
753  for (const CXXBaseSpecifier &BS : RD->bases()) {
754  CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
755  bool NewSubobject;
756  // Virtual bases constitute the same subobject. Non-virtual bases are
757  // always distinct subobjects.
758  if (BS.isVirtual())
759  NewSubobject = VBases.insert(BaseDecl).second;
760  else
761  NewSubobject = true;
762 
763  if (NewSubobject)
764  ++SubobjectsSeen[BaseDecl];
765 
766  // Only add subobjects which have public access throughout the entire chain.
767  bool PublicPath = ParentIsPublic && BS.getAccessSpecifier() == AS_public;
768  if (PublicPath)
769  PublicSubobjectsSeen.insert(BaseDecl);
770 
771  // Recurse on to each base subobject.
772  collectPublicBases(BaseDecl, SubobjectsSeen, VBases, PublicSubobjectsSeen,
773  PublicPath);
774  }
775 }
776 
779  llvm::DenseMap<CXXRecordDecl *, unsigned> SubobjectsSeen;
780  llvm::SmallSet<CXXRecordDecl *, 2> VBases;
781  llvm::SetVector<CXXRecordDecl *> PublicSubobjectsSeen;
782  SubobjectsSeen[RD] = 1;
783  PublicSubobjectsSeen.insert(RD);
784  collectPublicBases(RD, SubobjectsSeen, VBases, PublicSubobjectsSeen,
785  /*ParentIsPublic=*/true);
786 
787  for (CXXRecordDecl *PublicSubobject : PublicSubobjectsSeen) {
788  // Skip ambiguous objects.
789  if (SubobjectsSeen[PublicSubobject] > 1)
790  continue;
791 
792  Objects.push_back(PublicSubobject);
793  }
794 }
795 
796 /// CheckCXXThrowOperand - Validate the operand of a throw.
798  QualType ExceptionObjectTy, Expr *E) {
799  // If the type of the exception would be an incomplete type or a pointer
800  // to an incomplete type other than (cv) void the program is ill-formed.
801  QualType Ty = ExceptionObjectTy;
802  bool isPointer = false;
803  if (const PointerType* Ptr = Ty->getAs<PointerType>()) {
804  Ty = Ptr->getPointeeType();
805  isPointer = true;
806  }
807  if (!isPointer || !Ty->isVoidType()) {
808  if (RequireCompleteType(ThrowLoc, Ty,
809  isPointer ? diag::err_throw_incomplete_ptr
810  : diag::err_throw_incomplete,
811  E->getSourceRange()))
812  return true;
813 
814  if (RequireNonAbstractType(ThrowLoc, ExceptionObjectTy,
815  diag::err_throw_abstract_type, E))
816  return true;
817  }
818 
819  // If the exception has class type, we need additional handling.
820  CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
821  if (!RD)
822  return false;
823 
824  // If we are throwing a polymorphic class type or pointer thereof,
825  // exception handling will make use of the vtable.
826  MarkVTableUsed(ThrowLoc, RD);
827 
828  // If a pointer is thrown, the referenced object will not be destroyed.
829  if (isPointer)
830  return false;
831 
832  // If the class has a destructor, we must be able to call it.
833  if (!RD->hasIrrelevantDestructor()) {
834  if (CXXDestructorDecl *Destructor = LookupDestructor(RD)) {
835  MarkFunctionReferenced(E->getExprLoc(), Destructor);
836  CheckDestructorAccess(E->getExprLoc(), Destructor,
837  PDiag(diag::err_access_dtor_exception) << Ty);
838  if (DiagnoseUseOfDecl(Destructor, E->getExprLoc()))
839  return true;
840  }
841  }
842 
843  // The MSVC ABI creates a list of all types which can catch the exception
844  // object. This list also references the appropriate copy constructor to call
845  // if the object is caught by value and has a non-trivial copy constructor.
846  if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
847  // We are only interested in the public, unambiguous bases contained within
848  // the exception object. Bases which are ambiguous or otherwise
849  // inaccessible are not catchable types.
850  llvm::SmallVector<CXXRecordDecl *, 2> UnambiguousPublicSubobjects;
851  getUnambiguousPublicSubobjects(RD, UnambiguousPublicSubobjects);
852 
853  for (CXXRecordDecl *Subobject : UnambiguousPublicSubobjects) {
854  // Attempt to lookup the copy constructor. Various pieces of machinery
855  // will spring into action, like template instantiation, which means this
856  // cannot be a simple walk of the class's decls. Instead, we must perform
857  // lookup and overload resolution.
858  CXXConstructorDecl *CD = LookupCopyingConstructor(Subobject, 0);
859  if (!CD)
860  continue;
861 
862  // Mark the constructor referenced as it is used by this throw expression.
863  MarkFunctionReferenced(E->getExprLoc(), CD);
864 
865  // Skip this copy constructor if it is trivial, we don't need to record it
866  // in the catchable type data.
867  if (CD->isTrivial())
868  continue;
869 
870  // The copy constructor is non-trivial, create a mapping from this class
871  // type to this constructor.
872  // N.B. The selection of copy constructor is not sensitive to this
873  // particular throw-site. Lookup will be performed at the catch-site to
874  // ensure that the copy constructor is, in fact, accessible (via
875  // friendship or any other means).
876  Context.addCopyConstructorForExceptionObject(Subobject, CD);
877 
878  // We don't keep the instantiated default argument expressions around so
879  // we must rebuild them here.
880  for (unsigned I = 1, E = CD->getNumParams(); I != E; ++I) {
881  if (CheckCXXDefaultArgExpr(ThrowLoc, CD, CD->getParamDecl(I)))
882  return true;
883  }
884  }
885  }
886 
887  return false;
888 }
889 
891  ArrayRef<FunctionScopeInfo *> FunctionScopes, QualType ThisTy,
892  DeclContext *CurSemaContext, ASTContext &ASTCtx) {
893 
894  QualType ClassType = ThisTy->getPointeeType();
895  LambdaScopeInfo *CurLSI = nullptr;
896  DeclContext *CurDC = CurSemaContext;
897 
898  // Iterate through the stack of lambdas starting from the innermost lambda to
899  // the outermost lambda, checking if '*this' is ever captured by copy - since
900  // that could change the cv-qualifiers of the '*this' object.
901  // The object referred to by '*this' starts out with the cv-qualifiers of its
902  // member function. We then start with the innermost lambda and iterate
903  // outward checking to see if any lambda performs a by-copy capture of '*this'
904  // - and if so, any nested lambda must respect the 'constness' of that
905  // capturing lamdbda's call operator.
906  //
907 
908  // Since the FunctionScopeInfo stack is representative of the lexical
909  // nesting of the lambda expressions during initial parsing (and is the best
910  // place for querying information about captures about lambdas that are
911  // partially processed) and perhaps during instantiation of function templates
912  // that contain lambda expressions that need to be transformed BUT not
913  // necessarily during instantiation of a nested generic lambda's function call
914  // operator (which might even be instantiated at the end of the TU) - at which
915  // time the DeclContext tree is mature enough to query capture information
916  // reliably - we use a two pronged approach to walk through all the lexically
917  // enclosing lambda expressions:
918  //
919  // 1) Climb down the FunctionScopeInfo stack as long as each item represents
920  // a Lambda (i.e. LambdaScopeInfo) AND each LSI's 'closure-type' is lexically
921  // enclosed by the call-operator of the LSI below it on the stack (while
922  // tracking the enclosing DC for step 2 if needed). Note the topmost LSI on
923  // the stack represents the innermost lambda.
924  //
925  // 2) If we run out of enclosing LSI's, check if the enclosing DeclContext
926  // represents a lambda's call operator. If it does, we must be instantiating
927  // a generic lambda's call operator (represented by the Current LSI, and
928  // should be the only scenario where an inconsistency between the LSI and the
929  // DeclContext should occur), so climb out the DeclContexts if they
930  // represent lambdas, while querying the corresponding closure types
931  // regarding capture information.
932 
933  // 1) Climb down the function scope info stack.
934  for (int I = FunctionScopes.size();
935  I-- && isa<LambdaScopeInfo>(FunctionScopes[I]) &&
936  (!CurLSI || !CurLSI->Lambda || CurLSI->Lambda->getDeclContext() ==
937  cast<LambdaScopeInfo>(FunctionScopes[I])->CallOperator);
938  CurDC = getLambdaAwareParentOfDeclContext(CurDC)) {
939  CurLSI = cast<LambdaScopeInfo>(FunctionScopes[I]);
940 
941  if (!CurLSI->isCXXThisCaptured())
942  continue;
943 
944  auto C = CurLSI->getCXXThisCapture();
945 
946  if (C.isCopyCapture()) {
948  if (CurLSI->CallOperator->isConst())
949  ClassType.addConst();
950  return ASTCtx.getPointerType(ClassType);
951  }
952  }
953 
954  // 2) We've run out of ScopeInfos but check if CurDC is a lambda (which can
955  // happen during instantiation of its nested generic lambda call operator)
956  if (isLambdaCallOperator(CurDC)) {
957  assert(CurLSI && "While computing 'this' capture-type for a generic "
958  "lambda, we must have a corresponding LambdaScopeInfo");
960  "While computing 'this' capture-type for a generic lambda, when we "
961  "run out of enclosing LSI's, yet the enclosing DC is a "
962  "lambda-call-operator we must be (i.e. Current LSI) in a generic "
963  "lambda call oeprator");
964  assert(CurDC == getLambdaAwareParentOfDeclContext(CurLSI->CallOperator));
965 
966  auto IsThisCaptured =
967  [](CXXRecordDecl *Closure, bool &IsByCopy, bool &IsConst) {
968  IsConst = false;
969  IsByCopy = false;
970  for (auto &&C : Closure->captures()) {
971  if (C.capturesThis()) {
972  if (C.getCaptureKind() == LCK_StarThis)
973  IsByCopy = true;
974  if (Closure->getLambdaCallOperator()->isConst())
975  IsConst = true;
976  return true;
977  }
978  }
979  return false;
980  };
981 
982  bool IsByCopyCapture = false;
983  bool IsConstCapture = false;
984  CXXRecordDecl *Closure = cast<CXXRecordDecl>(CurDC->getParent());
985  while (Closure &&
986  IsThisCaptured(Closure, IsByCopyCapture, IsConstCapture)) {
987  if (IsByCopyCapture) {
989  if (IsConstCapture)
990  ClassType.addConst();
991  return ASTCtx.getPointerType(ClassType);
992  }
993  Closure = isLambdaCallOperator(Closure->getParent())
994  ? cast<CXXRecordDecl>(Closure->getParent()->getParent())
995  : nullptr;
996  }
997  }
998  return ASTCtx.getPointerType(ClassType);
999 }
1000 
1002  DeclContext *DC = getFunctionLevelDeclContext();
1003  QualType ThisTy = CXXThisTypeOverride;
1004 
1005  if (CXXMethodDecl *method = dyn_cast<CXXMethodDecl>(DC)) {
1006  if (method && method->isInstance())
1007  ThisTy = method->getThisType(Context);
1008  }
1009 
1010  if (ThisTy.isNull() && isLambdaCallOperator(CurContext) &&
1011  inTemplateInstantiation()) {
1012 
1013  assert(isa<CXXRecordDecl>(DC) &&
1014  "Trying to get 'this' type from static method?");
1015 
1016  // This is a lambda call operator that is being instantiated as a default
1017  // initializer. DC must point to the enclosing class type, so we can recover
1018  // the 'this' type from it.
1019 
1020  QualType ClassTy = Context.getTypeDeclType(cast<CXXRecordDecl>(DC));
1021  // There are no cv-qualifiers for 'this' within default initializers,
1022  // per [expr.prim.general]p4.
1023  ThisTy = Context.getPointerType(ClassTy);
1024  }
1025 
1026  // If we are within a lambda's call operator, the cv-qualifiers of 'this'
1027  // might need to be adjusted if the lambda or any of its enclosing lambda's
1028  // captures '*this' by copy.
1029  if (!ThisTy.isNull() && isLambdaCallOperator(CurContext))
1030  return adjustCVQualifiersForCXXThisWithinLambda(FunctionScopes, ThisTy,
1031  CurContext, Context);
1032  return ThisTy;
1033 }
1034 
1036  Decl *ContextDecl,
1037  unsigned CXXThisTypeQuals,
1038  bool Enabled)
1039  : S(S), OldCXXThisTypeOverride(S.CXXThisTypeOverride), Enabled(false)
1040 {
1041  if (!Enabled || !ContextDecl)
1042  return;
1043 
1044  CXXRecordDecl *Record = nullptr;
1045  if (ClassTemplateDecl *Template = dyn_cast<ClassTemplateDecl>(ContextDecl))
1046  Record = Template->getTemplatedDecl();
1047  else
1048  Record = cast<CXXRecordDecl>(ContextDecl);
1049 
1050  // We care only for CVR qualifiers here, so cut everything else.
1051  CXXThisTypeQuals &= Qualifiers::FastMask;
1053  = S.Context.getPointerType(
1054  S.Context.getRecordType(Record).withCVRQualifiers(CXXThisTypeQuals));
1055 
1056  this->Enabled = true;
1057 }
1058 
1059 
1061  if (Enabled) {
1062  S.CXXThisTypeOverride = OldCXXThisTypeOverride;
1063  }
1064 }
1065 
1067  QualType ThisTy, SourceLocation Loc,
1068  const bool ByCopy) {
1069 
1070  QualType AdjustedThisTy = ThisTy;
1071  // The type of the corresponding data member (not a 'this' pointer if 'by
1072  // copy').
1073  QualType CaptureThisFieldTy = ThisTy;
1074  if (ByCopy) {
1075  // If we are capturing the object referred to by '*this' by copy, ignore any
1076  // cv qualifiers inherited from the type of the member function for the type
1077  // of the closure-type's corresponding data member and any use of 'this'.
1078  CaptureThisFieldTy = ThisTy->getPointeeType();
1079  CaptureThisFieldTy.removeLocalCVRQualifiers(Qualifiers::CVRMask);
1080  AdjustedThisTy = Context.getPointerType(CaptureThisFieldTy);
1081  }
1082 
1083  FieldDecl *Field = FieldDecl::Create(
1084  Context, RD, Loc, Loc, nullptr, CaptureThisFieldTy,
1085  Context.getTrivialTypeSourceInfo(CaptureThisFieldTy, Loc), nullptr, false,
1086  ICIS_NoInit);
1087 
1088  Field->setImplicit(true);
1089  Field->setAccess(AS_private);
1090  RD->addDecl(Field);
1091  Expr *This =
1092  new (Context) CXXThisExpr(Loc, ThisTy, /*isImplicit*/ true);
1093  if (ByCopy) {
1094  Expr *StarThis = S.CreateBuiltinUnaryOp(Loc,
1095  UO_Deref,
1096  This).get();
1098  nullptr, CaptureThisFieldTy, Loc);
1099  InitializationKind InitKind = InitializationKind::CreateDirect(Loc, Loc, Loc);
1100  InitializationSequence Init(S, Entity, InitKind, StarThis);
1101  ExprResult ER = Init.Perform(S, Entity, InitKind, StarThis);
1102  if (ER.isInvalid()) return nullptr;
1103  return ER.get();
1104  }
1105  return This;
1106 }
1107 
1108 bool Sema::CheckCXXThisCapture(SourceLocation Loc, const bool Explicit,
1109  bool BuildAndDiagnose, const unsigned *const FunctionScopeIndexToStopAt,
1110  const bool ByCopy) {
1111  // We don't need to capture this in an unevaluated context.
1112  if (isUnevaluatedContext() && !Explicit)
1113  return true;
1114 
1115  assert((!ByCopy || Explicit) && "cannot implicitly capture *this by value");
1116 
1117  const unsigned MaxFunctionScopesIndex = FunctionScopeIndexToStopAt ?
1118  *FunctionScopeIndexToStopAt : FunctionScopes.size() - 1;
1119 
1120  // Check that we can capture the *enclosing object* (referred to by '*this')
1121  // by the capturing-entity/closure (lambda/block/etc) at
1122  // MaxFunctionScopesIndex-deep on the FunctionScopes stack.
1123 
1124  // Note: The *enclosing object* can only be captured by-value by a
1125  // closure that is a lambda, using the explicit notation:
1126  // [*this] { ... }.
1127  // Every other capture of the *enclosing object* results in its by-reference
1128  // capture.
1129 
1130  // For a closure 'L' (at MaxFunctionScopesIndex in the FunctionScopes
1131  // stack), we can capture the *enclosing object* only if:
1132  // - 'L' has an explicit byref or byval capture of the *enclosing object*
1133  // - or, 'L' has an implicit capture.
1134  // AND
1135  // -- there is no enclosing closure
1136  // -- or, there is some enclosing closure 'E' that has already captured the
1137  // *enclosing object*, and every intervening closure (if any) between 'E'
1138  // and 'L' can implicitly capture the *enclosing object*.
1139  // -- or, every enclosing closure can implicitly capture the
1140  // *enclosing object*
1141 
1142 
1143  unsigned NumCapturingClosures = 0;
1144  for (unsigned idx = MaxFunctionScopesIndex; idx != 0; idx--) {
1145  if (CapturingScopeInfo *CSI =
1146  dyn_cast<CapturingScopeInfo>(FunctionScopes[idx])) {
1147  if (CSI->CXXThisCaptureIndex != 0) {
1148  // 'this' is already being captured; there isn't anything more to do.
1149  CSI->Captures[CSI->CXXThisCaptureIndex - 1].markUsed(BuildAndDiagnose);
1150  break;
1151  }
1152  LambdaScopeInfo *LSI = dyn_cast<LambdaScopeInfo>(CSI);
1154  // This context can't implicitly capture 'this'; fail out.
1155  if (BuildAndDiagnose)
1156  Diag(Loc, diag::err_this_capture)
1157  << (Explicit && idx == MaxFunctionScopesIndex);
1158  return true;
1159  }
1160  if (CSI->ImpCaptureStyle == CapturingScopeInfo::ImpCap_LambdaByref ||
1161  CSI->ImpCaptureStyle == CapturingScopeInfo::ImpCap_LambdaByval ||
1162  CSI->ImpCaptureStyle == CapturingScopeInfo::ImpCap_Block ||
1163  CSI->ImpCaptureStyle == CapturingScopeInfo::ImpCap_CapturedRegion ||
1164  (Explicit && idx == MaxFunctionScopesIndex)) {
1165  // Regarding (Explicit && idx == MaxFunctionScopesIndex): only the first
1166  // iteration through can be an explicit capture, all enclosing closures,
1167  // if any, must perform implicit captures.
1168 
1169  // This closure can capture 'this'; continue looking upwards.
1170  NumCapturingClosures++;
1171  continue;
1172  }
1173  // This context can't implicitly capture 'this'; fail out.
1174  if (BuildAndDiagnose)
1175  Diag(Loc, diag::err_this_capture)
1176  << (Explicit && idx == MaxFunctionScopesIndex);
1177  return true;
1178  }
1179  break;
1180  }
1181  if (!BuildAndDiagnose) return false;
1182 
1183  // If we got here, then the closure at MaxFunctionScopesIndex on the
1184  // FunctionScopes stack, can capture the *enclosing object*, so capture it
1185  // (including implicit by-reference captures in any enclosing closures).
1186 
1187  // In the loop below, respect the ByCopy flag only for the closure requesting
1188  // the capture (i.e. first iteration through the loop below). Ignore it for
1189  // all enclosing closure's up to NumCapturingClosures (since they must be
1190  // implicitly capturing the *enclosing object* by reference (see loop
1191  // above)).
1192  assert((!ByCopy ||
1193  dyn_cast<LambdaScopeInfo>(FunctionScopes[MaxFunctionScopesIndex])) &&
1194  "Only a lambda can capture the enclosing object (referred to by "
1195  "*this) by copy");
1196  // FIXME: We need to delay this marking in PotentiallyPotentiallyEvaluated
1197  // contexts.
1198  QualType ThisTy = getCurrentThisType();
1199  for (unsigned idx = MaxFunctionScopesIndex; NumCapturingClosures;
1200  --idx, --NumCapturingClosures) {
1201  CapturingScopeInfo *CSI = cast<CapturingScopeInfo>(FunctionScopes[idx]);
1202  Expr *ThisExpr = nullptr;
1203 
1204  if (LambdaScopeInfo *LSI = dyn_cast<LambdaScopeInfo>(CSI)) {
1205  // For lambda expressions, build a field and an initializing expression,
1206  // and capture the *enclosing object* by copy only if this is the first
1207  // iteration.
1208  ThisExpr = captureThis(*this, Context, LSI->Lambda, ThisTy, Loc,
1209  ByCopy && idx == MaxFunctionScopesIndex);
1210 
1211  } else if (CapturedRegionScopeInfo *RSI
1212  = dyn_cast<CapturedRegionScopeInfo>(FunctionScopes[idx]))
1213  ThisExpr =
1214  captureThis(*this, Context, RSI->TheRecordDecl, ThisTy, Loc,
1215  false/*ByCopy*/);
1216 
1217  bool isNested = NumCapturingClosures > 1;
1218  CSI->addThisCapture(isNested, Loc, ThisExpr, ByCopy);
1219  }
1220  return false;
1221 }
1222 
1224  /// C++ 9.3.2: In the body of a non-static member function, the keyword this
1225  /// is a non-lvalue expression whose value is the address of the object for
1226  /// which the function is called.
1227 
1228  QualType ThisTy = getCurrentThisType();
1229  if (ThisTy.isNull()) return Diag(Loc, diag::err_invalid_this_use);
1230 
1231  CheckCXXThisCapture(Loc);
1232  return new (Context) CXXThisExpr(Loc, ThisTy, /*isImplicit=*/false);
1233 }
1234 
1236  // If we're outside the body of a member function, then we'll have a specified
1237  // type for 'this'.
1239  return false;
1240 
1241  // Determine whether we're looking into a class that's currently being
1242  // defined.
1243  CXXRecordDecl *Class = BaseType->getAsCXXRecordDecl();
1244  return Class && Class->isBeingDefined();
1245 }
1246 
1247 ExprResult
1249  SourceLocation LParenLoc,
1250  MultiExprArg exprs,
1251  SourceLocation RParenLoc) {
1252  if (!TypeRep)
1253  return ExprError();
1254 
1255  TypeSourceInfo *TInfo;
1256  QualType Ty = GetTypeFromParser(TypeRep, &TInfo);
1257  if (!TInfo)
1259 
1260  auto Result = BuildCXXTypeConstructExpr(TInfo, LParenLoc, exprs, RParenLoc);
1261  // Avoid creating a non-type-dependent expression that contains typos.
1262  // Non-type-dependent expressions are liable to be discarded without
1263  // checking for embedded typos.
1264  if (!Result.isInvalid() && Result.get()->isInstantiationDependent() &&
1265  !Result.get()->isTypeDependent())
1267  return Result;
1268 }
1269 
1270 /// ActOnCXXTypeConstructExpr - Parse construction of a specified type.
1271 /// Can be interpreted either as function-style casting ("int(x)")
1272 /// or class type construction ("ClassType(x,y,z)")
1273 /// or creation of a value-initialized type ("int()").
1274 ExprResult
1276  SourceLocation LParenLoc,
1277  MultiExprArg Exprs,
1278  SourceLocation RParenLoc) {
1279  QualType Ty = TInfo->getType();
1280  SourceLocation TyBeginLoc = TInfo->getTypeLoc().getBeginLoc();
1281 
1283  return CXXUnresolvedConstructExpr::Create(Context, TInfo, LParenLoc, Exprs,
1284  RParenLoc);
1285  }
1286 
1287  bool ListInitialization = LParenLoc.isInvalid();
1288  assert((!ListInitialization ||
1289  (Exprs.size() == 1 && isa<InitListExpr>(Exprs[0]))) &&
1290  "List initialization must have initializer list as expression.");
1291  SourceRange FullRange = SourceRange(TyBeginLoc,
1292  ListInitialization ? Exprs[0]->getSourceRange().getEnd() : RParenLoc);
1293 
1296  Exprs.size()
1297  ? ListInitialization
1299  : InitializationKind::CreateDirect(TyBeginLoc, LParenLoc,
1300  RParenLoc)
1301  : InitializationKind::CreateValue(TyBeginLoc, LParenLoc, RParenLoc);
1302 
1303  // C++1z [expr.type.conv]p1:
1304  // If the type is a placeholder for a deduced class type, [...perform class
1305  // template argument deduction...]
1306  DeducedType *Deduced = Ty->getContainedDeducedType();
1307  if (Deduced && isa<DeducedTemplateSpecializationType>(Deduced)) {
1309  Kind, Exprs);
1310  if (Ty.isNull())
1311  return ExprError();
1312  Entity = InitializedEntity::InitializeTemporary(TInfo, Ty);
1313  }
1314 
1315  // C++ [expr.type.conv]p1:
1316  // If the expression list is a parenthesized single expression, the type
1317  // conversion expression is equivalent (in definedness, and if defined in
1318  // meaning) to the corresponding cast expression.
1319  if (Exprs.size() == 1 && !ListInitialization &&
1320  !isa<InitListExpr>(Exprs[0])) {
1321  Expr *Arg = Exprs[0];
1322  return BuildCXXFunctionalCastExpr(TInfo, Ty, LParenLoc, Arg, RParenLoc);
1323  }
1324 
1325  // For an expression of the form T(), T shall not be an array type.
1326  QualType ElemTy = Ty;
1327  if (Ty->isArrayType()) {
1328  if (!ListInitialization)
1329  return ExprError(Diag(TyBeginLoc, diag::err_value_init_for_array_type)
1330  << FullRange);
1331  ElemTy = Context.getBaseElementType(Ty);
1332  }
1333 
1334  // There doesn't seem to be an explicit rule against this but sanity demands
1335  // we only construct objects with object types.
1336  if (Ty->isFunctionType())
1337  return ExprError(Diag(TyBeginLoc, diag::err_init_for_function_type)
1338  << Ty << FullRange);
1339 
1340  // C++17 [expr.type.conv]p2:
1341  // If the type is cv void and the initializer is (), the expression is a
1342  // prvalue of the specified type that performs no initialization.
1343  if (!Ty->isVoidType() &&
1344  RequireCompleteType(TyBeginLoc, ElemTy,
1345  diag::err_invalid_incomplete_type_use, FullRange))
1346  return ExprError();
1347 
1348  // Otherwise, the expression is a prvalue of the specified type whose
1349  // result object is direct-initialized (11.6) with the initializer.
1350  InitializationSequence InitSeq(*this, Entity, Kind, Exprs);
1351  ExprResult Result = InitSeq.Perform(*this, Entity, Kind, Exprs);
1352 
1353  if (Result.isInvalid())
1354  return Result;
1355 
1356  Expr *Inner = Result.get();
1357  if (CXXBindTemporaryExpr *BTE = dyn_cast_or_null<CXXBindTemporaryExpr>(Inner))
1358  Inner = BTE->getSubExpr();
1359  if (!isa<CXXTemporaryObjectExpr>(Inner) &&
1360  !isa<CXXScalarValueInitExpr>(Inner)) {
1361  // If we created a CXXTemporaryObjectExpr, that node also represents the
1362  // functional cast. Otherwise, create an explicit cast to represent
1363  // the syntactic form of a functional-style cast that was used here.
1364  //
1365  // FIXME: Creating a CXXFunctionalCastExpr around a CXXConstructExpr
1366  // would give a more consistent AST representation than using a
1367  // CXXTemporaryObjectExpr. It's also weird that the functional cast
1368  // is sometimes handled by initialization and sometimes not.
1369  QualType ResultType = Result.get()->getType();
1371  Context, ResultType, Expr::getValueKindForType(Ty), TInfo,
1372  CK_NoOp, Result.get(), /*Path=*/nullptr, LParenLoc, RParenLoc);
1373  }
1374 
1375  return Result;
1376 }
1377 
1378 /// \brief Determine whether the given function is a non-placement
1379 /// deallocation function.
1381  if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FD))
1382  return Method->isUsualDeallocationFunction();
1383 
1384  if (FD->getOverloadedOperator() != OO_Delete &&
1385  FD->getOverloadedOperator() != OO_Array_Delete)
1386  return false;
1387 
1388  unsigned UsualParams = 1;
1389 
1390  if (S.getLangOpts().SizedDeallocation && UsualParams < FD->getNumParams() &&
1392  FD->getParamDecl(UsualParams)->getType(),
1393  S.Context.getSizeType()))
1394  ++UsualParams;
1395 
1396  if (S.getLangOpts().AlignedAllocation && UsualParams < FD->getNumParams() &&
1398  FD->getParamDecl(UsualParams)->getType(),
1400  ++UsualParams;
1401 
1402  return UsualParams == FD->getNumParams();
1403 }
1404 
1405 namespace {
1406  struct UsualDeallocFnInfo {
1407  UsualDeallocFnInfo() : Found(), FD(nullptr) {}
1408  UsualDeallocFnInfo(Sema &S, DeclAccessPair Found)
1409  : Found(Found), FD(dyn_cast<FunctionDecl>(Found->getUnderlyingDecl())),
1410  Destroying(false), HasSizeT(false), HasAlignValT(false),
1411  CUDAPref(Sema::CFP_Native) {
1412  // A function template declaration is never a usual deallocation function.
1413  if (!FD)
1414  return;
1415  unsigned NumBaseParams = 1;
1416  if (FD->isDestroyingOperatorDelete()) {
1417  Destroying = true;
1418  ++NumBaseParams;
1419  }
1420  if (FD->getNumParams() == NumBaseParams + 2)
1421  HasAlignValT = HasSizeT = true;
1422  else if (FD->getNumParams() == NumBaseParams + 1) {
1423  HasSizeT = FD->getParamDecl(NumBaseParams)->getType()->isIntegerType();
1424  HasAlignValT = !HasSizeT;
1425  }
1426 
1427  // In CUDA, determine how much we'd like / dislike to call this.
1428  if (S.getLangOpts().CUDA)
1429  if (auto *Caller = dyn_cast<FunctionDecl>(S.CurContext))
1430  CUDAPref = S.IdentifyCUDAPreference(Caller, FD);
1431  }
1432 
1433  operator bool() const { return FD; }
1434 
1435  bool isBetterThan(const UsualDeallocFnInfo &Other, bool WantSize,
1436  bool WantAlign) const {
1437  // C++ P0722:
1438  // A destroying operator delete is preferred over a non-destroying
1439  // operator delete.
1440  if (Destroying != Other.Destroying)
1441  return Destroying;
1442 
1443  // C++17 [expr.delete]p10:
1444  // If the type has new-extended alignment, a function with a parameter
1445  // of type std::align_val_t is preferred; otherwise a function without
1446  // such a parameter is preferred
1447  if (HasAlignValT != Other.HasAlignValT)
1448  return HasAlignValT == WantAlign;
1449 
1450  if (HasSizeT != Other.HasSizeT)
1451  return HasSizeT == WantSize;
1452 
1453  // Use CUDA call preference as a tiebreaker.
1454  return CUDAPref > Other.CUDAPref;
1455  }
1456 
1457  DeclAccessPair Found;
1458  FunctionDecl *FD;
1459  bool Destroying, HasSizeT, HasAlignValT;
1461  };
1462 }
1463 
1464 /// Determine whether a type has new-extended alignment. This may be called when
1465 /// the type is incomplete (for a delete-expression with an incomplete pointee
1466 /// type), in which case it will conservatively return false if the alignment is
1467 /// not known.
1468 static bool hasNewExtendedAlignment(Sema &S, QualType AllocType) {
1469  return S.getLangOpts().AlignedAllocation &&
1470  S.getASTContext().getTypeAlignIfKnown(AllocType) >
1472 }
1473 
1474 /// Select the correct "usual" deallocation function to use from a selection of
1475 /// deallocation functions (either global or class-scope).
1476 static UsualDeallocFnInfo resolveDeallocationOverload(
1477  Sema &S, LookupResult &R, bool WantSize, bool WantAlign,
1478  llvm::SmallVectorImpl<UsualDeallocFnInfo> *BestFns = nullptr) {
1479  UsualDeallocFnInfo Best;
1480 
1481  for (auto I = R.begin(), E = R.end(); I != E; ++I) {
1482  UsualDeallocFnInfo Info(S, I.getPair());
1483  if (!Info || !isNonPlacementDeallocationFunction(S, Info.FD) ||
1484  Info.CUDAPref == Sema::CFP_Never)
1485  continue;
1486 
1487  if (!Best) {
1488  Best = Info;
1489  if (BestFns)
1490  BestFns->push_back(Info);
1491  continue;
1492  }
1493 
1494  if (Best.isBetterThan(Info, WantSize, WantAlign))
1495  continue;
1496 
1497  // If more than one preferred function is found, all non-preferred
1498  // functions are eliminated from further consideration.
1499  if (BestFns && Info.isBetterThan(Best, WantSize, WantAlign))
1500  BestFns->clear();
1501 
1502  Best = Info;
1503  if (BestFns)
1504  BestFns->push_back(Info);
1505  }
1506 
1507  return Best;
1508 }
1509 
1510 /// Determine whether a given type is a class for which 'delete[]' would call
1511 /// a member 'operator delete[]' with a 'size_t' parameter. This implies that
1512 /// we need to store the array size (even if the type is
1513 /// trivially-destructible).
1515  QualType allocType) {
1516  const RecordType *record =
1517  allocType->getBaseElementTypeUnsafe()->getAs<RecordType>();
1518  if (!record) return false;
1519 
1520  // Try to find an operator delete[] in class scope.
1521 
1522  DeclarationName deleteName =
1523  S.Context.DeclarationNames.getCXXOperatorName(OO_Array_Delete);
1524  LookupResult ops(S, deleteName, loc, Sema::LookupOrdinaryName);
1525  S.LookupQualifiedName(ops, record->getDecl());
1526 
1527  // We're just doing this for information.
1528  ops.suppressDiagnostics();
1529 
1530  // Very likely: there's no operator delete[].
1531  if (ops.empty()) return false;
1532 
1533  // If it's ambiguous, it should be illegal to call operator delete[]
1534  // on this thing, so it doesn't matter if we allocate extra space or not.
1535  if (ops.isAmbiguous()) return false;
1536 
1537  // C++17 [expr.delete]p10:
1538  // If the deallocation functions have class scope, the one without a
1539  // parameter of type std::size_t is selected.
1540  auto Best = resolveDeallocationOverload(
1541  S, ops, /*WantSize*/false,
1542  /*WantAlign*/hasNewExtendedAlignment(S, allocType));
1543  return Best && Best.HasSizeT;
1544 }
1545 
1546 /// \brief Parsed a C++ 'new' expression (C++ 5.3.4).
1547 ///
1548 /// E.g.:
1549 /// @code new (memory) int[size][4] @endcode
1550 /// or
1551 /// @code ::new Foo(23, "hello") @endcode
1552 ///
1553 /// \param StartLoc The first location of the expression.
1554 /// \param UseGlobal True if 'new' was prefixed with '::'.
1555 /// \param PlacementLParen Opening paren of the placement arguments.
1556 /// \param PlacementArgs Placement new arguments.
1557 /// \param PlacementRParen Closing paren of the placement arguments.
1558 /// \param TypeIdParens If the type is in parens, the source range.
1559 /// \param D The type to be allocated, as well as array dimensions.
1560 /// \param Initializer The initializing expression or initializer-list, or null
1561 /// if there is none.
1562 ExprResult
1563 Sema::ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal,
1564  SourceLocation PlacementLParen, MultiExprArg PlacementArgs,
1565  SourceLocation PlacementRParen, SourceRange TypeIdParens,
1566  Declarator &D, Expr *Initializer) {
1567  Expr *ArraySize = nullptr;
1568  // If the specified type is an array, unwrap it and save the expression.
1569  if (D.getNumTypeObjects() > 0 &&
1571  DeclaratorChunk &Chunk = D.getTypeObject(0);
1572  if (D.getDeclSpec().hasAutoTypeSpec())
1573  return ExprError(Diag(Chunk.Loc, diag::err_new_array_of_auto)
1574  << D.getSourceRange());
1575  if (Chunk.Arr.hasStatic)
1576  return ExprError(Diag(Chunk.Loc, diag::err_static_illegal_in_new)
1577  << D.getSourceRange());
1578  if (!Chunk.Arr.NumElts)
1579  return ExprError(Diag(Chunk.Loc, diag::err_array_new_needs_size)
1580  << D.getSourceRange());
1581 
1582  ArraySize = static_cast<Expr*>(Chunk.Arr.NumElts);
1583  D.DropFirstTypeObject();
1584  }
1585 
1586  // Every dimension shall be of constant size.
1587  if (ArraySize) {
1588  for (unsigned I = 0, N = D.getNumTypeObjects(); I < N; ++I) {
1590  break;
1591 
1593  if (Expr *NumElts = (Expr *)Array.NumElts) {
1594  if (!NumElts->isTypeDependent() && !NumElts->isValueDependent()) {
1595  if (getLangOpts().CPlusPlus14) {
1596  // C++1y [expr.new]p6: Every constant-expression in a noptr-new-declarator
1597  // shall be a converted constant expression (5.19) of type std::size_t
1598  // and shall evaluate to a strictly positive value.
1599  unsigned IntWidth = Context.getTargetInfo().getIntWidth();
1600  assert(IntWidth && "Builtin type of size 0?");
1601  llvm::APSInt Value(IntWidth);
1602  Array.NumElts
1604  CCEK_NewExpr)
1605  .get();
1606  } else {
1607  Array.NumElts
1608  = VerifyIntegerConstantExpression(NumElts, nullptr,
1609  diag::err_new_array_nonconst)
1610  .get();
1611  }
1612  if (!Array.NumElts)
1613  return ExprError();
1614  }
1615  }
1616  }
1617  }
1618 
1619  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, /*Scope=*/nullptr);
1620  QualType AllocType = TInfo->getType();
1621  if (D.isInvalidType())
1622  return ExprError();
1623 
1624  SourceRange DirectInitRange;
1625  if (ParenListExpr *List = dyn_cast_or_null<ParenListExpr>(Initializer))
1626  DirectInitRange = List->getSourceRange();
1627 
1628  return BuildCXXNew(SourceRange(StartLoc, D.getLocEnd()), UseGlobal,
1629  PlacementLParen,
1630  PlacementArgs,
1631  PlacementRParen,
1632  TypeIdParens,
1633  AllocType,
1634  TInfo,
1635  ArraySize,
1636  DirectInitRange,
1637  Initializer);
1638 }
1639 
1641  Expr *Init) {
1642  if (!Init)
1643  return true;
1644  if (ParenListExpr *PLE = dyn_cast<ParenListExpr>(Init))
1645  return PLE->getNumExprs() == 0;
1646  if (isa<ImplicitValueInitExpr>(Init))
1647  return true;
1648  else if (CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Init))
1649  return !CCE->isListInitialization() &&
1650  CCE->getConstructor()->isDefaultConstructor();
1651  else if (Style == CXXNewExpr::ListInit) {
1652  assert(isa<InitListExpr>(Init) &&
1653  "Shouldn't create list CXXConstructExprs for arrays.");
1654  return true;
1655  }
1656  return false;
1657 }
1658 
1659 // Emit a diagnostic if an aligned allocation/deallocation function that is not
1660 // implemented in the standard library is selected.
1662  SourceLocation Loc, bool IsDelete,
1663  Sema &S) {
1664  if (!S.getLangOpts().AlignedAllocationUnavailable)
1665  return;
1666 
1667  // Return if there is a definition.
1668  if (FD.isDefined())
1669  return;
1670 
1671  bool IsAligned = false;
1672  if (FD.isReplaceableGlobalAllocationFunction(&IsAligned) && IsAligned) {
1673  const llvm::Triple &T = S.getASTContext().getTargetInfo().getTriple();
1674  StringRef OSName = AvailabilityAttr::getPlatformNameSourceSpelling(
1676 
1677  S.Diag(Loc, diag::warn_aligned_allocation_unavailable)
1678  << IsDelete << FD.getType().getAsString() << OSName
1679  << alignedAllocMinVersion(T.getOS()).getAsString();
1680  S.Diag(Loc, diag::note_silence_unligned_allocation_unavailable);
1681  }
1682 }
1683 
1684 ExprResult
1685 Sema::BuildCXXNew(SourceRange Range, bool UseGlobal,
1686  SourceLocation PlacementLParen,
1687  MultiExprArg PlacementArgs,
1688  SourceLocation PlacementRParen,
1689  SourceRange TypeIdParens,
1690  QualType AllocType,
1691  TypeSourceInfo *AllocTypeInfo,
1692  Expr *ArraySize,
1693  SourceRange DirectInitRange,
1694  Expr *Initializer) {
1695  SourceRange TypeRange = AllocTypeInfo->getTypeLoc().getSourceRange();
1696  SourceLocation StartLoc = Range.getBegin();
1697 
1699  if (DirectInitRange.isValid()) {
1700  assert(Initializer && "Have parens but no initializer.");
1701  initStyle = CXXNewExpr::CallInit;
1702  } else if (Initializer && isa<InitListExpr>(Initializer))
1703  initStyle = CXXNewExpr::ListInit;
1704  else {
1705  assert((!Initializer || isa<ImplicitValueInitExpr>(Initializer) ||
1706  isa<CXXConstructExpr>(Initializer)) &&
1707  "Initializer expression that cannot have been implicitly created.");
1708  initStyle = CXXNewExpr::NoInit;
1709  }
1710 
1711  Expr **Inits = &Initializer;
1712  unsigned NumInits = Initializer ? 1 : 0;
1713  if (ParenListExpr *List = dyn_cast_or_null<ParenListExpr>(Initializer)) {
1714  assert(initStyle == CXXNewExpr::CallInit && "paren init for non-call init");
1715  Inits = List->getExprs();
1716  NumInits = List->getNumExprs();
1717  }
1718 
1719  // C++11 [expr.new]p15:
1720  // A new-expression that creates an object of type T initializes that
1721  // object as follows:
1723  // - If the new-initializer is omitted, the object is default-
1724  // initialized (8.5); if no initialization is performed,
1725  // the object has indeterminate value
1726  = initStyle == CXXNewExpr::NoInit
1728  // - Otherwise, the new-initializer is interpreted according to the
1729  // initialization rules of 8.5 for direct-initialization.
1730  : initStyle == CXXNewExpr::ListInit
1733  DirectInitRange.getBegin(),
1734  DirectInitRange.getEnd());
1735 
1736  // C++11 [dcl.spec.auto]p6. Deduce the type which 'auto' stands in for.
1737  auto *Deduced = AllocType->getContainedDeducedType();
1738  if (Deduced && isa<DeducedTemplateSpecializationType>(Deduced)) {
1739  if (ArraySize)
1740  return ExprError(Diag(ArraySize->getExprLoc(),
1741  diag::err_deduced_class_template_compound_type)
1742  << /*array*/ 2 << ArraySize->getSourceRange());
1743 
1744  InitializedEntity Entity
1745  = InitializedEntity::InitializeNew(StartLoc, AllocType);
1747  AllocTypeInfo, Entity, Kind, MultiExprArg(Inits, NumInits));
1748  if (AllocType.isNull())
1749  return ExprError();
1750  } else if (Deduced) {
1751  bool Braced = (initStyle == CXXNewExpr::ListInit);
1752  if (NumInits == 1) {
1753  if (auto p = dyn_cast_or_null<InitListExpr>(Inits[0])) {
1754  Inits = p->getInits();
1755  NumInits = p->getNumInits();
1756  Braced = true;
1757  }
1758  }
1759 
1760  if (initStyle == CXXNewExpr::NoInit || NumInits == 0)
1761  return ExprError(Diag(StartLoc, diag::err_auto_new_requires_ctor_arg)
1762  << AllocType << TypeRange);
1763  if (NumInits > 1) {
1764  Expr *FirstBad = Inits[1];
1765  return ExprError(Diag(FirstBad->getLocStart(),
1766  diag::err_auto_new_ctor_multiple_expressions)
1767  << AllocType << TypeRange);
1768  }
1769  if (Braced && !getLangOpts().CPlusPlus17)
1770  Diag(Initializer->getLocStart(), diag::ext_auto_new_list_init)
1771  << AllocType << TypeRange;
1772  Expr *Deduce = Inits[0];
1774  if (DeduceAutoType(AllocTypeInfo, Deduce, DeducedType) == DAR_Failed)
1775  return ExprError(Diag(StartLoc, diag::err_auto_new_deduction_failure)
1776  << AllocType << Deduce->getType()
1777  << TypeRange << Deduce->getSourceRange());
1778  if (DeducedType.isNull())
1779  return ExprError();
1780  AllocType = DeducedType;
1781  }
1782 
1783  // Per C++0x [expr.new]p5, the type being constructed may be a
1784  // typedef of an array type.
1785  if (!ArraySize) {
1786  if (const ConstantArrayType *Array
1787  = Context.getAsConstantArrayType(AllocType)) {
1788  ArraySize = IntegerLiteral::Create(Context, Array->getSize(),
1789  Context.getSizeType(),
1790  TypeRange.getEnd());
1791  AllocType = Array->getElementType();
1792  }
1793  }
1794 
1795  if (CheckAllocatedType(AllocType, TypeRange.getBegin(), TypeRange))
1796  return ExprError();
1797 
1798  if (initStyle == CXXNewExpr::ListInit &&
1799  isStdInitializerList(AllocType, nullptr)) {
1800  Diag(AllocTypeInfo->getTypeLoc().getBeginLoc(),
1801  diag::warn_dangling_std_initializer_list)
1802  << /*at end of FE*/0 << Inits[0]->getSourceRange();
1803  }
1804 
1805  // In ARC, infer 'retaining' for the allocated
1806  if (getLangOpts().ObjCAutoRefCount &&
1807  AllocType.getObjCLifetime() == Qualifiers::OCL_None &&
1808  AllocType->isObjCLifetimeType()) {
1809  AllocType = Context.getLifetimeQualifiedType(AllocType,
1810  AllocType->getObjCARCImplicitLifetime());
1811  }
1812 
1813  QualType ResultType = Context.getPointerType(AllocType);
1814 
1815  if (ArraySize && ArraySize->getType()->isNonOverloadPlaceholderType()) {
1816  ExprResult result = CheckPlaceholderExpr(ArraySize);
1817  if (result.isInvalid()) return ExprError();
1818  ArraySize = result.get();
1819  }
1820  // C++98 5.3.4p6: "The expression in a direct-new-declarator shall have
1821  // integral or enumeration type with a non-negative value."
1822  // C++11 [expr.new]p6: The expression [...] shall be of integral or unscoped
1823  // enumeration type, or a class type for which a single non-explicit
1824  // conversion function to integral or unscoped enumeration type exists.
1825  // C++1y [expr.new]p6: The expression [...] is implicitly converted to
1826  // std::size_t.
1827  llvm::Optional<uint64_t> KnownArraySize;
1828  if (ArraySize && !ArraySize->isTypeDependent()) {
1829  ExprResult ConvertedSize;
1830  if (getLangOpts().CPlusPlus14) {
1831  assert(Context.getTargetInfo().getIntWidth() && "Builtin type of size 0?");
1832 
1833  ConvertedSize = PerformImplicitConversion(ArraySize, Context.getSizeType(),
1834  AA_Converting);
1835 
1836  if (!ConvertedSize.isInvalid() &&
1837  ArraySize->getType()->getAs<RecordType>())
1838  // Diagnose the compatibility of this conversion.
1839  Diag(StartLoc, diag::warn_cxx98_compat_array_size_conversion)
1840  << ArraySize->getType() << 0 << "'size_t'";
1841  } else {
1842  class SizeConvertDiagnoser : public ICEConvertDiagnoser {
1843  protected:
1844  Expr *ArraySize;
1845 
1846  public:
1847  SizeConvertDiagnoser(Expr *ArraySize)
1848  : ICEConvertDiagnoser(/*AllowScopedEnumerations*/false, false, false),
1849  ArraySize(ArraySize) {}
1850 
1851  SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
1852  QualType T) override {
1853  return S.Diag(Loc, diag::err_array_size_not_integral)
1854  << S.getLangOpts().CPlusPlus11 << T;
1855  }
1856 
1857  SemaDiagnosticBuilder diagnoseIncomplete(
1858  Sema &S, SourceLocation Loc, QualType T) override {
1859  return S.Diag(Loc, diag::err_array_size_incomplete_type)
1860  << T << ArraySize->getSourceRange();
1861  }
1862 
1863  SemaDiagnosticBuilder diagnoseExplicitConv(
1864  Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
1865  return S.Diag(Loc, diag::err_array_size_explicit_conversion) << T << ConvTy;
1866  }
1867 
1868  SemaDiagnosticBuilder noteExplicitConv(
1869  Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
1870  return S.Diag(Conv->getLocation(), diag::note_array_size_conversion)
1871  << ConvTy->isEnumeralType() << ConvTy;
1872  }
1873 
1874  SemaDiagnosticBuilder diagnoseAmbiguous(
1875  Sema &S, SourceLocation Loc, QualType T) override {
1876  return S.Diag(Loc, diag::err_array_size_ambiguous_conversion) << T;
1877  }
1878 
1879  SemaDiagnosticBuilder noteAmbiguous(
1880  Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
1881  return S.Diag(Conv->getLocation(), diag::note_array_size_conversion)
1882  << ConvTy->isEnumeralType() << ConvTy;
1883  }
1884 
1885  SemaDiagnosticBuilder diagnoseConversion(Sema &S, SourceLocation Loc,
1886  QualType T,
1887  QualType ConvTy) override {
1888  return S.Diag(Loc,
1889  S.getLangOpts().CPlusPlus11
1890  ? diag::warn_cxx98_compat_array_size_conversion
1891  : diag::ext_array_size_conversion)
1892  << T << ConvTy->isEnumeralType() << ConvTy;
1893  }
1894  } SizeDiagnoser(ArraySize);
1895 
1896  ConvertedSize = PerformContextualImplicitConversion(StartLoc, ArraySize,
1897  SizeDiagnoser);
1898  }
1899  if (ConvertedSize.isInvalid())
1900  return ExprError();
1901 
1902  ArraySize = ConvertedSize.get();
1903  QualType SizeType = ArraySize->getType();
1904 
1905  if (!SizeType->isIntegralOrUnscopedEnumerationType())
1906  return ExprError();
1907 
1908  // C++98 [expr.new]p7:
1909  // The expression in a direct-new-declarator shall have integral type
1910  // with a non-negative value.
1911  //
1912  // Let's see if this is a constant < 0. If so, we reject it out of hand,
1913  // per CWG1464. Otherwise, if it's not a constant, we must have an
1914  // unparenthesized array type.
1915  if (!ArraySize->isValueDependent()) {
1916  llvm::APSInt Value;
1917  // We've already performed any required implicit conversion to integer or
1918  // unscoped enumeration type.
1919  // FIXME: Per CWG1464, we are required to check the value prior to
1920  // converting to size_t. This will never find a negative array size in
1921  // C++14 onwards, because Value is always unsigned here!
1922  if (ArraySize->isIntegerConstantExpr(Value, Context)) {
1923  if (Value.isSigned() && Value.isNegative()) {
1924  return ExprError(Diag(ArraySize->getLocStart(),
1925  diag::err_typecheck_negative_array_size)
1926  << ArraySize->getSourceRange());
1927  }
1928 
1929  if (!AllocType->isDependentType()) {
1930  unsigned ActiveSizeBits =
1932  if (ActiveSizeBits > ConstantArrayType::getMaxSizeBits(Context))
1933  return ExprError(Diag(ArraySize->getLocStart(),
1934  diag::err_array_too_large)
1935  << Value.toString(10)
1936  << ArraySize->getSourceRange());
1937  }
1938 
1939  KnownArraySize = Value.getZExtValue();
1940  } else if (TypeIdParens.isValid()) {
1941  // Can't have dynamic array size when the type-id is in parentheses.
1942  Diag(ArraySize->getLocStart(), diag::ext_new_paren_array_nonconst)
1943  << ArraySize->getSourceRange()
1944  << FixItHint::CreateRemoval(TypeIdParens.getBegin())
1945  << FixItHint::CreateRemoval(TypeIdParens.getEnd());
1946 
1947  TypeIdParens = SourceRange();
1948  }
1949  }
1950 
1951  // Note that we do *not* convert the argument in any way. It can
1952  // be signed, larger than size_t, whatever.
1953  }
1954 
1955  FunctionDecl *OperatorNew = nullptr;
1956  FunctionDecl *OperatorDelete = nullptr;
1957  unsigned Alignment =
1958  AllocType->isDependentType() ? 0 : Context.getTypeAlign(AllocType);
1959  unsigned NewAlignment = Context.getTargetInfo().getNewAlign();
1960  bool PassAlignment = getLangOpts().AlignedAllocation &&
1961  Alignment > NewAlignment;
1962 
1963  if (!AllocType->isDependentType() &&
1964  !Expr::hasAnyTypeDependentArguments(PlacementArgs) &&
1965  FindAllocationFunctions(StartLoc,
1966  SourceRange(PlacementLParen, PlacementRParen),
1967  UseGlobal, AllocType, ArraySize, PassAlignment,
1968  PlacementArgs, OperatorNew, OperatorDelete))
1969  return ExprError();
1970 
1971  // If this is an array allocation, compute whether the usual array
1972  // deallocation function for the type has a size_t parameter.
1973  bool UsualArrayDeleteWantsSize = false;
1974  if (ArraySize && !AllocType->isDependentType())
1975  UsualArrayDeleteWantsSize =
1976  doesUsualArrayDeleteWantSize(*this, StartLoc, AllocType);
1977 
1978  SmallVector<Expr *, 8> AllPlaceArgs;
1979  if (OperatorNew) {
1980  const FunctionProtoType *Proto =
1981  OperatorNew->getType()->getAs<FunctionProtoType>();
1982  VariadicCallType CallType = Proto->isVariadic() ? VariadicFunction
1984 
1985  // We've already converted the placement args, just fill in any default
1986  // arguments. Skip the first parameter because we don't have a corresponding
1987  // argument. Skip the second parameter too if we're passing in the
1988  // alignment; we've already filled it in.
1989  if (GatherArgumentsForCall(PlacementLParen, OperatorNew, Proto,
1990  PassAlignment ? 2 : 1, PlacementArgs,
1991  AllPlaceArgs, CallType))
1992  return ExprError();
1993 
1994  if (!AllPlaceArgs.empty())
1995  PlacementArgs = AllPlaceArgs;
1996 
1997  // FIXME: This is wrong: PlacementArgs misses out the first (size) argument.
1998  DiagnoseSentinelCalls(OperatorNew, PlacementLParen, PlacementArgs);
1999 
2000  // FIXME: Missing call to CheckFunctionCall or equivalent
2001 
2002  // Warn if the type is over-aligned and is being allocated by (unaligned)
2003  // global operator new.
2004  if (PlacementArgs.empty() && !PassAlignment &&
2005  (OperatorNew->isImplicit() ||
2006  (OperatorNew->getLocStart().isValid() &&
2007  getSourceManager().isInSystemHeader(OperatorNew->getLocStart())))) {
2008  if (Alignment > NewAlignment)
2009  Diag(StartLoc, diag::warn_overaligned_type)
2010  << AllocType
2011  << unsigned(Alignment / Context.getCharWidth())
2012  << unsigned(NewAlignment / Context.getCharWidth());
2013  }
2014  }
2015 
2016  // Array 'new' can't have any initializers except empty parentheses.
2017  // Initializer lists are also allowed, in C++11. Rely on the parser for the
2018  // dialect distinction.
2019  if (ArraySize && !isLegalArrayNewInitializer(initStyle, Initializer)) {
2020  SourceRange InitRange(Inits[0]->getLocStart(),
2021  Inits[NumInits - 1]->getLocEnd());
2022  Diag(StartLoc, diag::err_new_array_init_args) << InitRange;
2023  return ExprError();
2024  }
2025 
2026  // If we can perform the initialization, and we've not already done so,
2027  // do it now.
2028  if (!AllocType->isDependentType() &&
2030  llvm::makeArrayRef(Inits, NumInits))) {
2031  // The type we initialize is the complete type, including the array bound.
2032  QualType InitType;
2033  if (KnownArraySize)
2034  InitType = Context.getConstantArrayType(
2035  AllocType, llvm::APInt(Context.getTypeSize(Context.getSizeType()),
2036  *KnownArraySize),
2037  ArrayType::Normal, 0);
2038  else if (ArraySize)
2039  InitType =
2041  else
2042  InitType = AllocType;
2043 
2044  InitializedEntity Entity
2045  = InitializedEntity::InitializeNew(StartLoc, InitType);
2046  InitializationSequence InitSeq(*this, Entity, Kind,
2047  MultiExprArg(Inits, NumInits));
2048  ExprResult FullInit = InitSeq.Perform(*this, Entity, Kind,
2049  MultiExprArg(Inits, NumInits));
2050  if (FullInit.isInvalid())
2051  return ExprError();
2052 
2053  // FullInit is our initializer; strip off CXXBindTemporaryExprs, because
2054  // we don't want the initialized object to be destructed.
2055  // FIXME: We should not create these in the first place.
2056  if (CXXBindTemporaryExpr *Binder =
2057  dyn_cast_or_null<CXXBindTemporaryExpr>(FullInit.get()))
2058  FullInit = Binder->getSubExpr();
2059 
2060  Initializer = FullInit.get();
2061  }
2062 
2063  // Mark the new and delete operators as referenced.
2064  if (OperatorNew) {
2065  if (DiagnoseUseOfDecl(OperatorNew, StartLoc))
2066  return ExprError();
2067  MarkFunctionReferenced(StartLoc, OperatorNew);
2068  diagnoseUnavailableAlignedAllocation(*OperatorNew, StartLoc, false, *this);
2069  }
2070  if (OperatorDelete) {
2071  if (DiagnoseUseOfDecl(OperatorDelete, StartLoc))
2072  return ExprError();
2073  MarkFunctionReferenced(StartLoc, OperatorDelete);
2074  diagnoseUnavailableAlignedAllocation(*OperatorDelete, StartLoc, true, *this);
2075  }
2076 
2077  // C++0x [expr.new]p17:
2078  // If the new expression creates an array of objects of class type,
2079  // access and ambiguity control are done for the destructor.
2080  QualType BaseAllocType = Context.getBaseElementType(AllocType);
2081  if (ArraySize && !BaseAllocType->isDependentType()) {
2082  if (const RecordType *BaseRecordType = BaseAllocType->getAs<RecordType>()) {
2083  if (CXXDestructorDecl *dtor = LookupDestructor(
2084  cast<CXXRecordDecl>(BaseRecordType->getDecl()))) {
2085  MarkFunctionReferenced(StartLoc, dtor);
2086  CheckDestructorAccess(StartLoc, dtor,
2087  PDiag(diag::err_access_dtor)
2088  << BaseAllocType);
2089  if (DiagnoseUseOfDecl(dtor, StartLoc))
2090  return ExprError();
2091  }
2092  }
2093  }
2094 
2095  return new (Context)
2096  CXXNewExpr(Context, UseGlobal, OperatorNew, OperatorDelete, PassAlignment,
2097  UsualArrayDeleteWantsSize, PlacementArgs, TypeIdParens,
2098  ArraySize, initStyle, Initializer, ResultType, AllocTypeInfo,
2099  Range, DirectInitRange);
2100 }
2101 
2102 /// \brief Checks that a type is suitable as the allocated type
2103 /// in a new-expression.
2105  SourceRange R) {
2106  // C++ 5.3.4p1: "[The] type shall be a complete object type, but not an
2107  // abstract class type or array thereof.
2108  if (AllocType->isFunctionType())
2109  return Diag(Loc, diag::err_bad_new_type)
2110  << AllocType << 0 << R;
2111  else if (AllocType->isReferenceType())
2112  return Diag(Loc, diag::err_bad_new_type)
2113  << AllocType << 1 << R;
2114  else if (!AllocType->isDependentType() &&
2115  RequireCompleteType(Loc, AllocType, diag::err_new_incomplete_type,R))
2116  return true;
2117  else if (RequireNonAbstractType(Loc, AllocType,
2118  diag::err_allocation_of_abstract_type))
2119  return true;
2120  else if (AllocType->isVariablyModifiedType())
2121  return Diag(Loc, diag::err_variably_modified_new_type)
2122  << AllocType;
2123  else if (AllocType.getAddressSpace() != LangAS::Default)
2124  return Diag(Loc, diag::err_address_space_qualified_new)
2125  << AllocType.getUnqualifiedType()
2127  else if (getLangOpts().ObjCAutoRefCount) {
2128  if (const ArrayType *AT = Context.getAsArrayType(AllocType)) {
2129  QualType BaseAllocType = Context.getBaseElementType(AT);
2130  if (BaseAllocType.getObjCLifetime() == Qualifiers::OCL_None &&
2131  BaseAllocType->isObjCLifetimeType())
2132  return Diag(Loc, diag::err_arc_new_array_without_ownership)
2133  << BaseAllocType;
2134  }
2135  }
2136 
2137  return false;
2138 }
2139 
2140 static bool
2142  SmallVectorImpl<Expr *> &Args, bool &PassAlignment,
2143  FunctionDecl *&Operator,
2144  OverloadCandidateSet *AlignedCandidates = nullptr,
2145  Expr *AlignArg = nullptr) {
2146  OverloadCandidateSet Candidates(R.getNameLoc(),
2148  for (LookupResult::iterator Alloc = R.begin(), AllocEnd = R.end();
2149  Alloc != AllocEnd; ++Alloc) {
2150  // Even member operator new/delete are implicitly treated as
2151  // static, so don't use AddMemberCandidate.
2152  NamedDecl *D = (*Alloc)->getUnderlyingDecl();
2153 
2154  if (FunctionTemplateDecl *FnTemplate = dyn_cast<FunctionTemplateDecl>(D)) {
2155  S.AddTemplateOverloadCandidate(FnTemplate, Alloc.getPair(),
2156  /*ExplicitTemplateArgs=*/nullptr, Args,
2157  Candidates,
2158  /*SuppressUserConversions=*/false);
2159  continue;
2160  }
2161 
2162  FunctionDecl *Fn = cast<FunctionDecl>(D);
2163  S.AddOverloadCandidate(Fn, Alloc.getPair(), Args, Candidates,
2164  /*SuppressUserConversions=*/false);
2165  }
2166 
2167  // Do the resolution.
2169  switch (Candidates.BestViableFunction(S, R.getNameLoc(), Best)) {
2170  case OR_Success: {
2171  // Got one!
2172  FunctionDecl *FnDecl = Best->Function;
2173  if (S.CheckAllocationAccess(R.getNameLoc(), Range, R.getNamingClass(),
2174  Best->FoundDecl) == Sema::AR_inaccessible)
2175  return true;
2176 
2177  Operator = FnDecl;
2178  return false;
2179  }
2180 
2181  case OR_No_Viable_Function:
2182  // C++17 [expr.new]p13:
2183  // If no matching function is found and the allocated object type has
2184  // new-extended alignment, the alignment argument is removed from the
2185  // argument list, and overload resolution is performed again.
2186  if (PassAlignment) {
2187  PassAlignment = false;
2188  AlignArg = Args[1];
2189  Args.erase(Args.begin() + 1);
2190  return resolveAllocationOverload(S, R, Range, Args, PassAlignment,
2191  Operator, &Candidates, AlignArg);
2192  }
2193 
2194  // MSVC will fall back on trying to find a matching global operator new
2195  // if operator new[] cannot be found. Also, MSVC will leak by not
2196  // generating a call to operator delete or operator delete[], but we
2197  // will not replicate that bug.
2198  // FIXME: Find out how this interacts with the std::align_val_t fallback
2199  // once MSVC implements it.
2200  if (R.getLookupName().getCXXOverloadedOperator() == OO_Array_New &&
2201  S.Context.getLangOpts().MSVCCompat) {
2202  R.clear();
2205  // FIXME: This will give bad diagnostics pointing at the wrong functions.
2206  return resolveAllocationOverload(S, R, Range, Args, PassAlignment,
2207  Operator, nullptr);
2208  }
2209 
2210  S.Diag(R.getNameLoc(), diag::err_ovl_no_viable_function_in_call)
2211  << R.getLookupName() << Range;
2212 
2213  // If we have aligned candidates, only note the align_val_t candidates
2214  // from AlignedCandidates and the non-align_val_t candidates from
2215  // Candidates.
2216  if (AlignedCandidates) {
2217  auto IsAligned = [](OverloadCandidate &C) {
2218  return C.Function->getNumParams() > 1 &&
2219  C.Function->getParamDecl(1)->getType()->isAlignValT();
2220  };
2221  auto IsUnaligned = [&](OverloadCandidate &C) { return !IsAligned(C); };
2222 
2223  // This was an overaligned allocation, so list the aligned candidates
2224  // first.
2225  Args.insert(Args.begin() + 1, AlignArg);
2226  AlignedCandidates->NoteCandidates(S, OCD_AllCandidates, Args, "",
2227  R.getNameLoc(), IsAligned);
2228  Args.erase(Args.begin() + 1);
2229  Candidates.NoteCandidates(S, OCD_AllCandidates, Args, "", R.getNameLoc(),
2230  IsUnaligned);
2231  } else {
2232  Candidates.NoteCandidates(S, OCD_AllCandidates, Args);
2233  }
2234  return true;
2235 
2236  case OR_Ambiguous:
2237  S.Diag(R.getNameLoc(), diag::err_ovl_ambiguous_call)
2238  << R.getLookupName() << Range;
2239  Candidates.NoteCandidates(S, OCD_ViableCandidates, Args);
2240  return true;
2241 
2242  case OR_Deleted: {
2243  S.Diag(R.getNameLoc(), diag::err_ovl_deleted_call)
2244  << Best->Function->isDeleted()
2245  << R.getLookupName()
2246  << S.getDeletedOrUnavailableSuffix(Best->Function)
2247  << Range;
2248  Candidates.NoteCandidates(S, OCD_AllCandidates, Args);
2249  return true;
2250  }
2251  }
2252  llvm_unreachable("Unreachable, bad result from BestViableFunction");
2253 }
2254 
2255 
2256 /// FindAllocationFunctions - Finds the overloads of operator new and delete
2257 /// that are appropriate for the allocation.
2259  bool UseGlobal, QualType AllocType,
2260  bool IsArray, bool &PassAlignment,
2261  MultiExprArg PlaceArgs,
2262  FunctionDecl *&OperatorNew,
2263  FunctionDecl *&OperatorDelete) {
2264  // --- Choosing an allocation function ---
2265  // C++ 5.3.4p8 - 14 & 18
2266  // 1) If UseGlobal is true, only look in the global scope. Else, also look
2267  // in the scope of the allocated class.
2268  // 2) If an array size is given, look for operator new[], else look for
2269  // operator new.
2270  // 3) The first argument is always size_t. Append the arguments from the
2271  // placement form.
2272 
2273  SmallVector<Expr*, 8> AllocArgs;
2274  AllocArgs.reserve((PassAlignment ? 2 : 1) + PlaceArgs.size());
2275 
2276  // We don't care about the actual value of these arguments.
2277  // FIXME: Should the Sema create the expression and embed it in the syntax
2278  // tree? Or should the consumer just recalculate the value?
2279  // FIXME: Using a dummy value will interact poorly with attribute enable_if.
2280  IntegerLiteral Size(Context, llvm::APInt::getNullValue(
2282  Context.getSizeType(),
2283  SourceLocation());
2284  AllocArgs.push_back(&Size);
2285 
2286  QualType AlignValT = Context.VoidTy;
2287  if (PassAlignment) {
2289  AlignValT = Context.getTypeDeclType(getStdAlignValT());
2290  }
2291  CXXScalarValueInitExpr Align(AlignValT, nullptr, SourceLocation());
2292  if (PassAlignment)
2293  AllocArgs.push_back(&Align);
2294 
2295  AllocArgs.insert(AllocArgs.end(), PlaceArgs.begin(), PlaceArgs.end());
2296 
2297  // C++ [expr.new]p8:
2298  // If the allocated type is a non-array type, the allocation
2299  // function's name is operator new and the deallocation function's
2300  // name is operator delete. If the allocated type is an array
2301  // type, the allocation function's name is operator new[] and the
2302  // deallocation function's name is operator delete[].
2304  IsArray ? OO_Array_New : OO_New);
2305 
2306  QualType AllocElemType = Context.getBaseElementType(AllocType);
2307 
2308  // Find the allocation function.
2309  {
2310  LookupResult R(*this, NewName, StartLoc, LookupOrdinaryName);
2311 
2312  // C++1z [expr.new]p9:
2313  // If the new-expression begins with a unary :: operator, the allocation
2314  // function's name is looked up in the global scope. Otherwise, if the
2315  // allocated type is a class type T or array thereof, the allocation
2316  // function's name is looked up in the scope of T.
2317  if (AllocElemType->isRecordType() && !UseGlobal)
2318  LookupQualifiedName(R, AllocElemType->getAsCXXRecordDecl());
2319 
2320  // We can see ambiguity here if the allocation function is found in
2321  // multiple base classes.
2322  if (R.isAmbiguous())
2323  return true;
2324 
2325  // If this lookup fails to find the name, or if the allocated type is not
2326  // a class type, the allocation function's name is looked up in the
2327  // global scope.
2328  if (R.empty())
2330 
2331  assert(!R.empty() && "implicitly declared allocation functions not found");
2332  assert(!R.isAmbiguous() && "global allocation functions are ambiguous");
2333 
2334  // We do our own custom access checks below.
2335  R.suppressDiagnostics();
2336 
2337  if (resolveAllocationOverload(*this, R, Range, AllocArgs, PassAlignment,
2338  OperatorNew))
2339  return true;
2340  }
2341 
2342  // We don't need an operator delete if we're running under -fno-exceptions.
2343  if (!getLangOpts().Exceptions) {
2344  OperatorDelete = nullptr;
2345  return false;
2346  }
2347 
2348  // Note, the name of OperatorNew might have been changed from array to
2349  // non-array by resolveAllocationOverload.
2351  OperatorNew->getDeclName().getCXXOverloadedOperator() == OO_Array_New
2352  ? OO_Array_Delete
2353  : OO_Delete);
2354 
2355  // C++ [expr.new]p19:
2356  //
2357  // If the new-expression begins with a unary :: operator, the
2358  // deallocation function's name is looked up in the global
2359  // scope. Otherwise, if the allocated type is a class type T or an
2360  // array thereof, the deallocation function's name is looked up in
2361  // the scope of T. If this lookup fails to find the name, or if
2362  // the allocated type is not a class type or array thereof, the
2363  // deallocation function's name is looked up in the global scope.
2364  LookupResult FoundDelete(*this, DeleteName, StartLoc, LookupOrdinaryName);
2365  if (AllocElemType->isRecordType() && !UseGlobal) {
2366  CXXRecordDecl *RD
2367  = cast<CXXRecordDecl>(AllocElemType->getAs<RecordType>()->getDecl());
2368  LookupQualifiedName(FoundDelete, RD);
2369  }
2370  if (FoundDelete.isAmbiguous())
2371  return true; // FIXME: clean up expressions?
2372 
2373  bool FoundGlobalDelete = FoundDelete.empty();
2374  if (FoundDelete.empty()) {
2377  }
2378 
2379  FoundDelete.suppressDiagnostics();
2380 
2382 
2383  // Whether we're looking for a placement operator delete is dictated
2384  // by whether we selected a placement operator new, not by whether
2385  // we had explicit placement arguments. This matters for things like
2386  // struct A { void *operator new(size_t, int = 0); ... };
2387  // A *a = new A()
2388  //
2389  // We don't have any definition for what a "placement allocation function"
2390  // is, but we assume it's any allocation function whose
2391  // parameter-declaration-clause is anything other than (size_t).
2392  //
2393  // FIXME: Should (size_t, std::align_val_t) also be considered non-placement?
2394  // This affects whether an exception from the constructor of an overaligned
2395  // type uses the sized or non-sized form of aligned operator delete.
2396  bool isPlacementNew = !PlaceArgs.empty() || OperatorNew->param_size() != 1 ||
2397  OperatorNew->isVariadic();
2398 
2399  if (isPlacementNew) {
2400  // C++ [expr.new]p20:
2401  // A declaration of a placement deallocation function matches the
2402  // declaration of a placement allocation function if it has the
2403  // same number of parameters and, after parameter transformations
2404  // (8.3.5), all parameter types except the first are
2405  // identical. [...]
2406  //
2407  // To perform this comparison, we compute the function type that
2408  // the deallocation function should have, and use that type both
2409  // for template argument deduction and for comparison purposes.
2410  QualType ExpectedFunctionType;
2411  {
2412  const FunctionProtoType *Proto
2413  = OperatorNew->getType()->getAs<FunctionProtoType>();
2414 
2415  SmallVector<QualType, 4> ArgTypes;
2416  ArgTypes.push_back(Context.VoidPtrTy);
2417  for (unsigned I = 1, N = Proto->getNumParams(); I < N; ++I)
2418  ArgTypes.push_back(Proto->getParamType(I));
2419 
2421  // FIXME: This is not part of the standard's rule.
2422  EPI.Variadic = Proto->isVariadic();
2423 
2424  ExpectedFunctionType
2425  = Context.getFunctionType(Context.VoidTy, ArgTypes, EPI);
2426  }
2427 
2428  for (LookupResult::iterator D = FoundDelete.begin(),
2429  DEnd = FoundDelete.end();
2430  D != DEnd; ++D) {
2431  FunctionDecl *Fn = nullptr;
2432  if (FunctionTemplateDecl *FnTmpl =
2433  dyn_cast<FunctionTemplateDecl>((*D)->getUnderlyingDecl())) {
2434  // Perform template argument deduction to try to match the
2435  // expected function type.
2436  TemplateDeductionInfo Info(StartLoc);
2437  if (DeduceTemplateArguments(FnTmpl, nullptr, ExpectedFunctionType, Fn,
2438  Info))
2439  continue;
2440  } else
2441  Fn = cast<FunctionDecl>((*D)->getUnderlyingDecl());
2442 
2444  ExpectedFunctionType,
2445  /*AdjustExcpetionSpec*/true),
2446  ExpectedFunctionType))
2447  Matches.push_back(std::make_pair(D.getPair(), Fn));
2448  }
2449 
2450  if (getLangOpts().CUDA)
2451  EraseUnwantedCUDAMatches(dyn_cast<FunctionDecl>(CurContext), Matches);
2452  } else {
2453  // C++1y [expr.new]p22:
2454  // For a non-placement allocation function, the normal deallocation
2455  // function lookup is used
2456  //
2457  // Per [expr.delete]p10, this lookup prefers a member operator delete
2458  // without a size_t argument, but prefers a non-member operator delete
2459  // with a size_t where possible (which it always is in this case).
2461  UsualDeallocFnInfo Selected = resolveDeallocationOverload(
2462  *this, FoundDelete, /*WantSize*/ FoundGlobalDelete,
2463  /*WantAlign*/ hasNewExtendedAlignment(*this, AllocElemType),
2464  &BestDeallocFns);
2465  if (Selected)
2466  Matches.push_back(std::make_pair(Selected.Found, Selected.FD));
2467  else {
2468  // If we failed to select an operator, all remaining functions are viable
2469  // but ambiguous.
2470  for (auto Fn : BestDeallocFns)
2471  Matches.push_back(std::make_pair(Fn.Found, Fn.FD));
2472  }
2473  }
2474 
2475  // C++ [expr.new]p20:
2476  // [...] If the lookup finds a single matching deallocation
2477  // function, that function will be called; otherwise, no
2478  // deallocation function will be called.
2479  if (Matches.size() == 1) {
2480  OperatorDelete = Matches[0].second;
2481 
2482  // C++1z [expr.new]p23:
2483  // If the lookup finds a usual deallocation function (3.7.4.2)
2484  // with a parameter of type std::size_t and that function, considered
2485  // as a placement deallocation function, would have been
2486  // selected as a match for the allocation function, the program
2487  // is ill-formed.
2488  if (getLangOpts().CPlusPlus11 && isPlacementNew &&
2489  isNonPlacementDeallocationFunction(*this, OperatorDelete)) {
2490  UsualDeallocFnInfo Info(*this,
2491  DeclAccessPair::make(OperatorDelete, AS_public));
2492  // Core issue, per mail to core reflector, 2016-10-09:
2493  // If this is a member operator delete, and there is a corresponding
2494  // non-sized member operator delete, this isn't /really/ a sized
2495  // deallocation function, it just happens to have a size_t parameter.
2496  bool IsSizedDelete = Info.HasSizeT;
2497  if (IsSizedDelete && !FoundGlobalDelete) {
2498  auto NonSizedDelete =
2499  resolveDeallocationOverload(*this, FoundDelete, /*WantSize*/false,
2500  /*WantAlign*/Info.HasAlignValT);
2501  if (NonSizedDelete && !NonSizedDelete.HasSizeT &&
2502  NonSizedDelete.HasAlignValT == Info.HasAlignValT)
2503  IsSizedDelete = false;
2504  }
2505 
2506  if (IsSizedDelete) {
2507  SourceRange R = PlaceArgs.empty()
2508  ? SourceRange()
2509  : SourceRange(PlaceArgs.front()->getLocStart(),
2510  PlaceArgs.back()->getLocEnd());
2511  Diag(StartLoc, diag::err_placement_new_non_placement_delete) << R;
2512  if (!OperatorDelete->isImplicit())
2513  Diag(OperatorDelete->getLocation(), diag::note_previous_decl)
2514  << DeleteName;
2515  }
2516  }
2517 
2518  CheckAllocationAccess(StartLoc, Range, FoundDelete.getNamingClass(),
2519  Matches[0].first);
2520  } else if (!Matches.empty()) {
2521  // We found multiple suitable operators. Per [expr.new]p20, that means we
2522  // call no 'operator delete' function, but we should at least warn the user.
2523  // FIXME: Suppress this warning if the construction cannot throw.
2524  Diag(StartLoc, diag::warn_ambiguous_suitable_delete_function_found)
2525  << DeleteName << AllocElemType;
2526 
2527  for (auto &Match : Matches)
2528  Diag(Match.second->getLocation(),
2529  diag::note_member_declared_here) << DeleteName;
2530  }
2531 
2532  return false;
2533 }
2534 
2535 /// DeclareGlobalNewDelete - Declare the global forms of operator new and
2536 /// delete. These are:
2537 /// @code
2538 /// // C++03:
2539 /// void* operator new(std::size_t) throw(std::bad_alloc);
2540 /// void* operator new[](std::size_t) throw(std::bad_alloc);
2541 /// void operator delete(void *) throw();
2542 /// void operator delete[](void *) throw();
2543 /// // C++11:
2544 /// void* operator new(std::size_t);
2545 /// void* operator new[](std::size_t);
2546 /// void operator delete(void *) noexcept;
2547 /// void operator delete[](void *) noexcept;
2548 /// // C++1y:
2549 /// void* operator new(std::size_t);
2550 /// void* operator new[](std::size_t);
2551 /// void operator delete(void *) noexcept;
2552 /// void operator delete[](void *) noexcept;
2553 /// void operator delete(void *, std::size_t) noexcept;
2554 /// void operator delete[](void *, std::size_t) noexcept;
2555 /// @endcode
2556 /// Note that the placement and nothrow forms of new are *not* implicitly
2557 /// declared. Their use requires including <new>.
2560  return;
2561 
2562  // C++ [basic.std.dynamic]p2:
2563  // [...] The following allocation and deallocation functions (18.4) are
2564  // implicitly declared in global scope in each translation unit of a
2565  // program
2566  //
2567  // C++03:
2568  // void* operator new(std::size_t) throw(std::bad_alloc);
2569  // void* operator new[](std::size_t) throw(std::bad_alloc);
2570  // void operator delete(void*) throw();
2571  // void operator delete[](void*) throw();
2572  // C++11:
2573  // void* operator new(std::size_t);
2574  // void* operator new[](std::size_t);
2575  // void operator delete(void*) noexcept;
2576  // void operator delete[](void*) noexcept;
2577  // C++1y:
2578  // void* operator new(std::size_t);
2579  // void* operator new[](std::size_t);
2580  // void operator delete(void*) noexcept;
2581  // void operator delete[](void*) noexcept;
2582  // void operator delete(void*, std::size_t) noexcept;
2583  // void operator delete[](void*, std::size_t) noexcept;
2584  //
2585  // These implicit declarations introduce only the function names operator
2586  // new, operator new[], operator delete, operator delete[].
2587  //
2588  // Here, we need to refer to std::bad_alloc, so we will implicitly declare
2589  // "std" or "bad_alloc" as necessary to form the exception specification.
2590  // However, we do not make these implicit declarations visible to name
2591  // lookup.
2592  if (!StdBadAlloc && !getLangOpts().CPlusPlus11) {
2593  // The "std::bad_alloc" class has not yet been declared, so build it
2594  // implicitly.
2598  &PP.getIdentifierTable().get("bad_alloc"),
2599  nullptr);
2600  getStdBadAlloc()->setImplicit(true);
2601  }
2602  if (!StdAlignValT && getLangOpts().AlignedAllocation) {
2603  // The "std::align_val_t" enum class has not yet been declared, so build it
2604  // implicitly.
2605  auto *AlignValT = EnumDecl::Create(
2607  &PP.getIdentifierTable().get("align_val_t"), nullptr, true, true, true);
2608  AlignValT->setIntegerType(Context.getSizeType());
2609  AlignValT->setPromotionType(Context.getSizeType());
2610  AlignValT->setImplicit(true);
2611  StdAlignValT = AlignValT;
2612  }
2613 
2614  GlobalNewDeleteDeclared = true;
2615 
2617  QualType SizeT = Context.getSizeType();
2618 
2619  auto DeclareGlobalAllocationFunctions = [&](OverloadedOperatorKind Kind,
2620  QualType Return, QualType Param) {
2622  Params.push_back(Param);
2623 
2624  // Create up to four variants of the function (sized/aligned).
2625  bool HasSizedVariant = getLangOpts().SizedDeallocation &&
2626  (Kind == OO_Delete || Kind == OO_Array_Delete);
2627  bool HasAlignedVariant = getLangOpts().AlignedAllocation;
2628 
2629  int NumSizeVariants = (HasSizedVariant ? 2 : 1);
2630  int NumAlignVariants = (HasAlignedVariant ? 2 : 1);
2631  for (int Sized = 0; Sized < NumSizeVariants; ++Sized) {
2632  if (Sized)
2633  Params.push_back(SizeT);
2634 
2635  for (int Aligned = 0; Aligned < NumAlignVariants; ++Aligned) {
2636  if (Aligned)
2637  Params.push_back(Context.getTypeDeclType(getStdAlignValT()));
2638 
2640  Context.DeclarationNames.getCXXOperatorName(Kind), Return, Params);
2641 
2642  if (Aligned)
2643  Params.pop_back();
2644  }
2645  }
2646  };
2647 
2648  DeclareGlobalAllocationFunctions(OO_New, VoidPtr, SizeT);
2649  DeclareGlobalAllocationFunctions(OO_Array_New, VoidPtr, SizeT);
2650  DeclareGlobalAllocationFunctions(OO_Delete, Context.VoidTy, VoidPtr);
2651  DeclareGlobalAllocationFunctions(OO_Array_Delete, Context.VoidTy, VoidPtr);
2652 }
2653 
2654 /// DeclareGlobalAllocationFunction - Declares a single implicit global
2655 /// allocation function if it doesn't already exist.
2657  QualType Return,
2658  ArrayRef<QualType> Params) {
2660 
2661  // Check if this function is already declared.
2662  DeclContext::lookup_result R = GlobalCtx->lookup(Name);
2663  for (DeclContext::lookup_iterator Alloc = R.begin(), AllocEnd = R.end();
2664  Alloc != AllocEnd; ++Alloc) {
2665  // Only look at non-template functions, as it is the predefined,
2666  // non-templated allocation function we are trying to declare here.
2667  if (FunctionDecl *Func = dyn_cast<FunctionDecl>(*Alloc)) {
2668  if (Func->getNumParams() == Params.size()) {
2669  llvm::SmallVector<QualType, 3> FuncParams;
2670  for (auto *P : Func->parameters())
2671  FuncParams.push_back(
2672  Context.getCanonicalType(P->getType().getUnqualifiedType()));
2673  if (llvm::makeArrayRef(FuncParams) == Params) {
2674  // Make the function visible to name lookup, even if we found it in
2675  // an unimported module. It either is an implicitly-declared global
2676  // allocation function, or is suppressing that function.
2677  Func->setVisibleDespiteOwningModule();
2678  return;
2679  }
2680  }
2681  }
2682  }
2683 
2685 
2686  QualType BadAllocType;
2687  bool HasBadAllocExceptionSpec
2688  = (Name.getCXXOverloadedOperator() == OO_New ||
2689  Name.getCXXOverloadedOperator() == OO_Array_New);
2690  if (HasBadAllocExceptionSpec) {
2691  if (!getLangOpts().CPlusPlus11) {
2692  BadAllocType = Context.getTypeDeclType(getStdBadAlloc());
2693  assert(StdBadAlloc && "Must have std::bad_alloc declared");
2695  EPI.ExceptionSpec.Exceptions = llvm::makeArrayRef(BadAllocType);
2696  }
2697  } else {
2698  EPI.ExceptionSpec =
2699  getLangOpts().CPlusPlus11 ? EST_BasicNoexcept : EST_DynamicNone;
2700  }
2701 
2702  auto CreateAllocationFunctionDecl = [&](Attr *ExtraAttr) {
2703  QualType FnType = Context.getFunctionType(Return, Params, EPI);
2705  Context, GlobalCtx, SourceLocation(), SourceLocation(), Name,
2706  FnType, /*TInfo=*/nullptr, SC_None, false, true);
2707  Alloc->setImplicit();
2708  // Global allocation functions should always be visible.
2710 
2711  // Implicit sized deallocation functions always have default visibility.
2712  Alloc->addAttr(
2713  VisibilityAttr::CreateImplicit(Context, VisibilityAttr::Default));
2714 
2716  for (QualType T : Params) {
2717  ParamDecls.push_back(ParmVarDecl::Create(
2718  Context, Alloc, SourceLocation(), SourceLocation(), nullptr, T,
2719  /*TInfo=*/nullptr, SC_None, nullptr));
2720  ParamDecls.back()->setImplicit();
2721  }
2722  Alloc->setParams(ParamDecls);
2723  if (ExtraAttr)
2724  Alloc->addAttr(ExtraAttr);
2726  IdResolver.tryAddTopLevelDecl(Alloc, Name);
2727  };
2728 
2729  if (!LangOpts.CUDA)
2730  CreateAllocationFunctionDecl(nullptr);
2731  else {
2732  // Host and device get their own declaration so each can be
2733  // defined or re-declared independently.
2734  CreateAllocationFunctionDecl(CUDAHostAttr::CreateImplicit(Context));
2735  CreateAllocationFunctionDecl(CUDADeviceAttr::CreateImplicit(Context));
2736  }
2737 }
2738 
2740  bool CanProvideSize,
2741  bool Overaligned,
2742  DeclarationName Name) {
2744 
2745  LookupResult FoundDelete(*this, Name, StartLoc, LookupOrdinaryName);
2747 
2748  // FIXME: It's possible for this to result in ambiguity, through a
2749  // user-declared variadic operator delete or the enable_if attribute. We
2750  // should probably not consider those cases to be usual deallocation
2751  // functions. But for now we just make an arbitrary choice in that case.
2752  auto Result = resolveDeallocationOverload(*this, FoundDelete, CanProvideSize,
2753  Overaligned);
2754  assert(Result.FD && "operator delete missing from global scope?");
2755  return Result.FD;
2756 }
2757 
2759  CXXRecordDecl *RD) {
2761 
2762  FunctionDecl *OperatorDelete = nullptr;
2763  if (FindDeallocationFunction(Loc, RD, Name, OperatorDelete))
2764  return nullptr;
2765  if (OperatorDelete)
2766  return OperatorDelete;
2767 
2768  // If there's no class-specific operator delete, look up the global
2769  // non-array delete.
2771  Loc, true, hasNewExtendedAlignment(*this, Context.getRecordType(RD)),
2772  Name);
2773 }
2774 
2776  DeclarationName Name,
2777  FunctionDecl *&Operator, bool Diagnose) {
2778  LookupResult Found(*this, Name, StartLoc, LookupOrdinaryName);
2779  // Try to find operator delete/operator delete[] in class scope.
2780  LookupQualifiedName(Found, RD);
2781 
2782  if (Found.isAmbiguous())
2783  return true;
2784 
2785  Found.suppressDiagnostics();
2786 
2787  bool Overaligned = hasNewExtendedAlignment(*this, Context.getRecordType(RD));
2788 
2789  // C++17 [expr.delete]p10:
2790  // If the deallocation functions have class scope, the one without a
2791  // parameter of type std::size_t is selected.
2793  resolveDeallocationOverload(*this, Found, /*WantSize*/ false,
2794  /*WantAlign*/ Overaligned, &Matches);
2795 
2796  // If we could find an overload, use it.
2797  if (Matches.size() == 1) {
2798  Operator = cast<CXXMethodDecl>(Matches[0].FD);
2799 
2800  // FIXME: DiagnoseUseOfDecl?
2801  if (Operator->isDeleted()) {
2802  if (Diagnose) {
2803  Diag(StartLoc, diag::err_deleted_function_use);
2804  NoteDeletedFunction(Operator);
2805  }
2806  return true;
2807  }
2808 
2809  if (CheckAllocationAccess(StartLoc, SourceRange(), Found.getNamingClass(),
2810  Matches[0].Found, Diagnose) == AR_inaccessible)
2811  return true;
2812 
2813  return false;
2814  }
2815 
2816  // We found multiple suitable operators; complain about the ambiguity.
2817  // FIXME: The standard doesn't say to do this; it appears that the intent
2818  // is that this should never happen.
2819  if (!Matches.empty()) {
2820  if (Diagnose) {
2821  Diag(StartLoc, diag::err_ambiguous_suitable_delete_member_function_found)
2822  << Name << RD;
2823  for (auto &Match : Matches)
2824  Diag(Match.FD->getLocation(), diag::note_member_declared_here) << Name;
2825  }
2826  return true;
2827  }
2828 
2829  // We did find operator delete/operator delete[] declarations, but
2830  // none of them were suitable.
2831  if (!Found.empty()) {
2832  if (Diagnose) {
2833  Diag(StartLoc, diag::err_no_suitable_delete_member_function_found)
2834  << Name << RD;
2835 
2836  for (NamedDecl *D : Found)
2837  Diag(D->getUnderlyingDecl()->getLocation(),
2838  diag::note_member_declared_here) << Name;
2839  }
2840  return true;
2841  }
2842 
2843  Operator = nullptr;
2844  return false;
2845 }
2846 
2847 namespace {
2848 /// \brief Checks whether delete-expression, and new-expression used for
2849 /// initializing deletee have the same array form.
2850 class MismatchingNewDeleteDetector {
2851 public:
2852  enum MismatchResult {
2853  /// Indicates that there is no mismatch or a mismatch cannot be proven.
2854  NoMismatch,
2855  /// Indicates that variable is initialized with mismatching form of \a new.
2856  VarInitMismatches,
2857  /// Indicates that member is initialized with mismatching form of \a new.
2858  MemberInitMismatches,
2859  /// Indicates that 1 or more constructors' definitions could not been
2860  /// analyzed, and they will be checked again at the end of translation unit.
2861  AnalyzeLater
2862  };
2863 
2864  /// \param EndOfTU True, if this is the final analysis at the end of
2865  /// translation unit. False, if this is the initial analysis at the point
2866  /// delete-expression was encountered.
2867  explicit MismatchingNewDeleteDetector(bool EndOfTU)
2868  : Field(nullptr), IsArrayForm(false), EndOfTU(EndOfTU),
2869  HasUndefinedConstructors(false) {}
2870 
2871  /// \brief Checks whether pointee of a delete-expression is initialized with
2872  /// matching form of new-expression.
2873  ///
2874  /// If return value is \c VarInitMismatches or \c MemberInitMismatches at the
2875  /// point where delete-expression is encountered, then a warning will be
2876  /// issued immediately. If return value is \c AnalyzeLater at the point where
2877  /// delete-expression is seen, then member will be analyzed at the end of
2878  /// translation unit. \c AnalyzeLater is returned iff at least one constructor
2879  /// couldn't be analyzed. If at least one constructor initializes the member
2880  /// with matching type of new, the return value is \c NoMismatch.
2881  MismatchResult analyzeDeleteExpr(const CXXDeleteExpr *DE);
2882  /// \brief Analyzes a class member.
2883  /// \param Field Class member to analyze.
2884  /// \param DeleteWasArrayForm Array form-ness of the delete-expression used
2885  /// for deleting the \p Field.
2886  MismatchResult analyzeField(FieldDecl *Field, bool DeleteWasArrayForm);
2887  FieldDecl *Field;
2888  /// List of mismatching new-expressions used for initialization of the pointee
2890  /// Indicates whether delete-expression was in array form.
2891  bool IsArrayForm;
2892 
2893 private:
2894  const bool EndOfTU;
2895  /// \brief Indicates that there is at least one constructor without body.
2896  bool HasUndefinedConstructors;
2897  /// \brief Returns \c CXXNewExpr from given initialization expression.
2898  /// \param E Expression used for initializing pointee in delete-expression.
2899  /// E can be a single-element \c InitListExpr consisting of new-expression.
2900  const CXXNewExpr *getNewExprFromInitListOrExpr(const Expr *E);
2901  /// \brief Returns whether member is initialized with mismatching form of
2902  /// \c new either by the member initializer or in-class initialization.
2903  ///
2904  /// If bodies of all constructors are not visible at the end of translation
2905  /// unit or at least one constructor initializes member with the matching
2906  /// form of \c new, mismatch cannot be proven, and this function will return
2907  /// \c NoMismatch.
2908  MismatchResult analyzeMemberExpr(const MemberExpr *ME);
2909  /// \brief Returns whether variable is initialized with mismatching form of
2910  /// \c new.
2911  ///
2912  /// If variable is initialized with matching form of \c new or variable is not
2913  /// initialized with a \c new expression, this function will return true.
2914  /// If variable is initialized with mismatching form of \c new, returns false.
2915  /// \param D Variable to analyze.
2916  bool hasMatchingVarInit(const DeclRefExpr *D);
2917  /// \brief Checks whether the constructor initializes pointee with mismatching
2918  /// form of \c new.
2919  ///
2920  /// Returns true, if member is initialized with matching form of \c new in
2921  /// member initializer list. Returns false, if member is initialized with the
2922  /// matching form of \c new in this constructor's initializer or given
2923  /// constructor isn't defined at the point where delete-expression is seen, or
2924  /// member isn't initialized by the constructor.
2925  bool hasMatchingNewInCtor(const CXXConstructorDecl *CD);
2926  /// \brief Checks whether member is initialized with matching form of
2927  /// \c new in member initializer list.
2928  bool hasMatchingNewInCtorInit(const CXXCtorInitializer *CI);
2929  /// Checks whether member is initialized with mismatching form of \c new by
2930  /// in-class initializer.
2931  MismatchResult analyzeInClassInitializer();
2932 };
2933 }
2934 
2935 MismatchingNewDeleteDetector::MismatchResult
2936 MismatchingNewDeleteDetector::analyzeDeleteExpr(const CXXDeleteExpr *DE) {
2937  NewExprs.clear();
2938  assert(DE && "Expected delete-expression");
2939  IsArrayForm = DE->isArrayForm();
2940  const Expr *E = DE->getArgument()->IgnoreParenImpCasts();
2941  if (const MemberExpr *ME = dyn_cast<const MemberExpr>(E)) {
2942  return analyzeMemberExpr(ME);
2943  } else if (const DeclRefExpr *D = dyn_cast<const DeclRefExpr>(E)) {
2944  if (!hasMatchingVarInit(D))
2945  return VarInitMismatches;
2946  }
2947  return NoMismatch;
2948 }
2949 
2950 const CXXNewExpr *
2951 MismatchingNewDeleteDetector::getNewExprFromInitListOrExpr(const Expr *E) {
2952  assert(E != nullptr && "Expected a valid initializer expression");
2953  E = E->IgnoreParenImpCasts();
2954  if (const InitListExpr *ILE = dyn_cast<const InitListExpr>(E)) {
2955  if (ILE->getNumInits() == 1)
2956  E = dyn_cast<const CXXNewExpr>(ILE->getInit(0)->IgnoreParenImpCasts());
2957  }
2958 
2959  return dyn_cast_or_null<const CXXNewExpr>(E);
2960 }
2961 
2962 bool MismatchingNewDeleteDetector::hasMatchingNewInCtorInit(
2963  const CXXCtorInitializer *CI) {
2964  const CXXNewExpr *NE = nullptr;
2965  if (Field == CI->getMember() &&
2966  (NE = getNewExprFromInitListOrExpr(CI->getInit()))) {
2967  if (NE->isArray() == IsArrayForm)
2968  return true;
2969  else
2970  NewExprs.push_back(NE);
2971  }
2972  return false;
2973 }
2974 
2975 bool MismatchingNewDeleteDetector::hasMatchingNewInCtor(
2976  const CXXConstructorDecl *CD) {
2977  if (CD->isImplicit())
2978  return false;
2979  const FunctionDecl *Definition = CD;
2980  if (!CD->isThisDeclarationADefinition() && !CD->isDefined(Definition)) {
2981  HasUndefinedConstructors = true;
2982  return EndOfTU;
2983  }
2984  for (const auto *CI : cast<const CXXConstructorDecl>(Definition)->inits()) {
2985  if (hasMatchingNewInCtorInit(CI))
2986  return true;
2987  }
2988  return false;
2989 }
2990 
2991 MismatchingNewDeleteDetector::MismatchResult
2992 MismatchingNewDeleteDetector::analyzeInClassInitializer() {
2993  assert(Field != nullptr && "This should be called only for members");
2994  const Expr *InitExpr = Field->getInClassInitializer();
2995  if (!InitExpr)
2996  return EndOfTU ? NoMismatch : AnalyzeLater;
2997  if (const CXXNewExpr *NE = getNewExprFromInitListOrExpr(InitExpr)) {
2998  if (NE->isArray() != IsArrayForm) {
2999  NewExprs.push_back(NE);
3000  return MemberInitMismatches;
3001  }
3002  }
3003  return NoMismatch;
3004 }
3005 
3006 MismatchingNewDeleteDetector::MismatchResult
3007 MismatchingNewDeleteDetector::analyzeField(FieldDecl *Field,
3008  bool DeleteWasArrayForm) {
3009  assert(Field != nullptr && "Analysis requires a valid class member.");
3010  this->Field = Field;
3011  IsArrayForm = DeleteWasArrayForm;
3012  const CXXRecordDecl *RD = cast<const CXXRecordDecl>(Field->getParent());
3013  for (const auto *CD : RD->ctors()) {
3014  if (hasMatchingNewInCtor(CD))
3015  return NoMismatch;
3016  }
3017  if (HasUndefinedConstructors)
3018  return EndOfTU ? NoMismatch : AnalyzeLater;
3019  if (!NewExprs.empty())
3020  return MemberInitMismatches;
3021  return Field->hasInClassInitializer() ? analyzeInClassInitializer()
3022  : NoMismatch;
3023 }
3024 
3025 MismatchingNewDeleteDetector::MismatchResult
3026 MismatchingNewDeleteDetector::analyzeMemberExpr(const MemberExpr *ME) {
3027  assert(ME != nullptr && "Expected a member expression");
3028  if (FieldDecl *F = dyn_cast<FieldDecl>(ME->getMemberDecl()))
3029  return analyzeField(F, IsArrayForm);
3030  return NoMismatch;
3031 }
3032 
3033 bool MismatchingNewDeleteDetector::hasMatchingVarInit(const DeclRefExpr *D) {
3034  const CXXNewExpr *NE = nullptr;
3035  if (const VarDecl *VD = dyn_cast<const VarDecl>(D->getDecl())) {
3036  if (VD->hasInit() && (NE = getNewExprFromInitListOrExpr(VD->getInit())) &&
3037  NE->isArray() != IsArrayForm) {
3038  NewExprs.push_back(NE);
3039  }
3040  }
3041  return NewExprs.empty();
3042 }
3043 
3044 static void
3046  const MismatchingNewDeleteDetector &Detector) {
3047  SourceLocation EndOfDelete = SemaRef.getLocForEndOfToken(DeleteLoc);
3048  FixItHint H;
3049  if (!Detector.IsArrayForm)
3050  H = FixItHint::CreateInsertion(EndOfDelete, "[]");
3051  else {
3053  DeleteLoc, tok::l_square, SemaRef.getSourceManager(),
3054  SemaRef.getLangOpts(), true);
3055  if (RSquare.isValid())
3056  H = FixItHint::CreateRemoval(SourceRange(EndOfDelete, RSquare));
3057  }
3058  SemaRef.Diag(DeleteLoc, diag::warn_mismatched_delete_new)
3059  << Detector.IsArrayForm << H;
3060 
3061  for (const auto *NE : Detector.NewExprs)
3062  SemaRef.Diag(NE->getExprLoc(), diag::note_allocated_here)
3063  << Detector.IsArrayForm;
3064 }
3065 
3066 void Sema::AnalyzeDeleteExprMismatch(const CXXDeleteExpr *DE) {
3067  if (Diags.isIgnored(diag::warn_mismatched_delete_new, SourceLocation()))
3068  return;
3069  MismatchingNewDeleteDetector Detector(/*EndOfTU=*/false);
3070  switch (Detector.analyzeDeleteExpr(DE)) {
3071  case MismatchingNewDeleteDetector::VarInitMismatches:
3072  case MismatchingNewDeleteDetector::MemberInitMismatches: {
3073  DiagnoseMismatchedNewDelete(*this, DE->getLocStart(), Detector);
3074  break;
3075  }
3076  case MismatchingNewDeleteDetector::AnalyzeLater: {
3077  DeleteExprs[Detector.Field].push_back(
3078  std::make_pair(DE->getLocStart(), DE->isArrayForm()));
3079  break;
3080  }
3081  case MismatchingNewDeleteDetector::NoMismatch:
3082  break;
3083  }
3084 }
3085 
3086 void Sema::AnalyzeDeleteExprMismatch(FieldDecl *Field, SourceLocation DeleteLoc,
3087  bool DeleteWasArrayForm) {
3088  MismatchingNewDeleteDetector Detector(/*EndOfTU=*/true);
3089  switch (Detector.analyzeField(Field, DeleteWasArrayForm)) {
3090  case MismatchingNewDeleteDetector::VarInitMismatches:
3091  llvm_unreachable("This analysis should have been done for class members.");
3092  case MismatchingNewDeleteDetector::AnalyzeLater:
3093  llvm_unreachable("Analysis cannot be postponed any point beyond end of "
3094  "translation unit.");
3095  case MismatchingNewDeleteDetector::MemberInitMismatches:
3096  DiagnoseMismatchedNewDelete(*this, DeleteLoc, Detector);
3097  break;
3098  case MismatchingNewDeleteDetector::NoMismatch:
3099  break;
3100  }
3101 }
3102 
3103 /// ActOnCXXDelete - Parsed a C++ 'delete' expression (C++ 5.3.5), as in:
3104 /// @code ::delete ptr; @endcode
3105 /// or
3106 /// @code delete [] ptr; @endcode
3107 ExprResult
3108 Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
3109  bool ArrayForm, Expr *ExE) {
3110  // C++ [expr.delete]p1:
3111  // The operand shall have a pointer type, or a class type having a single
3112  // non-explicit conversion function to a pointer type. The result has type
3113  // void.
3114  //
3115  // DR599 amends "pointer type" to "pointer to object type" in both cases.
3116 
3117  ExprResult Ex = ExE;
3118  FunctionDecl *OperatorDelete = nullptr;
3119  bool ArrayFormAsWritten = ArrayForm;
3120  bool UsualArrayDeleteWantsSize = false;
3121 
3122  if (!Ex.get()->isTypeDependent()) {
3123  // Perform lvalue-to-rvalue cast, if needed.
3124  Ex = DefaultLvalueConversion(Ex.get());
3125  if (Ex.isInvalid())
3126  return ExprError();
3127 
3128  QualType Type = Ex.get()->getType();
3129 
3130  class DeleteConverter : public ContextualImplicitConverter {
3131  public:
3132  DeleteConverter() : ContextualImplicitConverter(false, true) {}
3133 
3134  bool match(QualType ConvType) override {
3135  // FIXME: If we have an operator T* and an operator void*, we must pick
3136  // the operator T*.
3137  if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>())
3138  if (ConvPtrType->getPointeeType()->isIncompleteOrObjectType())
3139  return true;
3140  return false;
3141  }
3142 
3143  SemaDiagnosticBuilder diagnoseNoMatch(Sema &S, SourceLocation Loc,
3144  QualType T) override {
3145  return S.Diag(Loc, diag::err_delete_operand) << T;
3146  }
3147 
3148  SemaDiagnosticBuilder diagnoseIncomplete(Sema &S, SourceLocation Loc,
3149  QualType T) override {
3150  return S.Diag(Loc, diag::err_delete_incomplete_class_type) << T;
3151  }
3152 
3153  SemaDiagnosticBuilder diagnoseExplicitConv(Sema &S, SourceLocation Loc,
3154  QualType T,
3155  QualType ConvTy) override {
3156  return S.Diag(Loc, diag::err_delete_explicit_conversion) << T << ConvTy;
3157  }
3158 
3159  SemaDiagnosticBuilder noteExplicitConv(Sema &S, CXXConversionDecl *Conv,
3160  QualType ConvTy) override {
3161  return S.Diag(Conv->getLocation(), diag::note_delete_conversion)
3162  << ConvTy;
3163  }
3164 
3165  SemaDiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
3166  QualType T) override {
3167  return S.Diag(Loc, diag::err_ambiguous_delete_operand) << T;
3168  }
3169 
3170  SemaDiagnosticBuilder noteAmbiguous(Sema &S, CXXConversionDecl *Conv,
3171  QualType ConvTy) override {
3172  return S.Diag(Conv->getLocation(), diag::note_delete_conversion)
3173  << ConvTy;
3174  }
3175 
3176  SemaDiagnosticBuilder diagnoseConversion(Sema &S, SourceLocation Loc,
3177  QualType T,
3178  QualType ConvTy) override {
3179  llvm_unreachable("conversion functions are permitted");
3180  }
3181  } Converter;
3182 
3183  Ex = PerformContextualImplicitConversion(StartLoc, Ex.get(), Converter);
3184  if (Ex.isInvalid())
3185  return ExprError();
3186  Type = Ex.get()->getType();
3187  if (!Converter.match(Type))
3188  // FIXME: PerformContextualImplicitConversion should return ExprError
3189  // itself in this case.
3190  return ExprError();
3191 
3192  QualType Pointee = Type->getAs<PointerType>()->getPointeeType();
3193  QualType PointeeElem = Context.getBaseElementType(Pointee);
3194 
3195  if (Pointee.getAddressSpace() != LangAS::Default)
3196  return Diag(Ex.get()->getLocStart(),
3197  diag::err_address_space_qualified_delete)
3198  << Pointee.getUnqualifiedType()
3200 
3201  CXXRecordDecl *PointeeRD = nullptr;
3202  if (Pointee->isVoidType() && !isSFINAEContext()) {
3203  // The C++ standard bans deleting a pointer to a non-object type, which
3204  // effectively bans deletion of "void*". However, most compilers support
3205  // this, so we treat it as a warning unless we're in a SFINAE context.
3206  Diag(StartLoc, diag::ext_delete_void_ptr_operand)
3207  << Type << Ex.get()->getSourceRange();
3208  } else if (Pointee->isFunctionType() || Pointee->isVoidType()) {
3209  return ExprError(Diag(StartLoc, diag::err_delete_operand)
3210  << Type << Ex.get()->getSourceRange());
3211  } else if (!Pointee->isDependentType()) {
3212  // FIXME: This can result in errors if the definition was imported from a
3213  // module but is hidden.
3214  if (!RequireCompleteType(StartLoc, Pointee,
3215  diag::warn_delete_incomplete, Ex.get())) {
3216  if (const RecordType *RT = PointeeElem->getAs<RecordType>())
3217  PointeeRD = cast<CXXRecordDecl>(RT->getDecl());
3218  }
3219  }
3220 
3221  if (Pointee->isArrayType() && !ArrayForm) {
3222  Diag(StartLoc, diag::warn_delete_array_type)
3223  << Type << Ex.get()->getSourceRange()
3224  << FixItHint::CreateInsertion(getLocForEndOfToken(StartLoc), "[]");
3225  ArrayForm = true;
3226  }
3227 
3229  ArrayForm ? OO_Array_Delete : OO_Delete);
3230 
3231  if (PointeeRD) {
3232  if (!UseGlobal &&
3233  FindDeallocationFunction(StartLoc, PointeeRD, DeleteName,
3234  OperatorDelete))
3235  return ExprError();
3236 
3237  // If we're allocating an array of records, check whether the
3238  // usual operator delete[] has a size_t parameter.
3239  if (ArrayForm) {
3240  // If the user specifically asked to use the global allocator,
3241  // we'll need to do the lookup into the class.
3242  if (UseGlobal)
3243  UsualArrayDeleteWantsSize =
3244  doesUsualArrayDeleteWantSize(*this, StartLoc, PointeeElem);
3245 
3246  // Otherwise, the usual operator delete[] should be the
3247  // function we just found.
3248  else if (OperatorDelete && isa<CXXMethodDecl>(OperatorDelete))
3249  UsualArrayDeleteWantsSize =
3250  UsualDeallocFnInfo(*this,
3251  DeclAccessPair::make(OperatorDelete, AS_public))
3252  .HasSizeT;
3253  }
3254 
3255  if (!PointeeRD->hasIrrelevantDestructor())
3256  if (CXXDestructorDecl *Dtor = LookupDestructor(PointeeRD)) {
3257  MarkFunctionReferenced(StartLoc,
3258  const_cast<CXXDestructorDecl*>(Dtor));
3259  if (DiagnoseUseOfDecl(Dtor, StartLoc))
3260  return ExprError();
3261  }
3262 
3263  CheckVirtualDtorCall(PointeeRD->getDestructor(), StartLoc,
3264  /*IsDelete=*/true, /*CallCanBeVirtual=*/true,
3265  /*WarnOnNonAbstractTypes=*/!ArrayForm,
3266  SourceLocation());
3267  }
3268 
3269  if (!OperatorDelete) {
3270  bool IsComplete = isCompleteType(StartLoc, Pointee);
3271  bool CanProvideSize =
3272  IsComplete && (!ArrayForm || UsualArrayDeleteWantsSize ||
3273  Pointee.isDestructedType());
3274  bool Overaligned = hasNewExtendedAlignment(*this, Pointee);
3275 
3276  // Look for a global declaration.
3277  OperatorDelete = FindUsualDeallocationFunction(StartLoc, CanProvideSize,
3278  Overaligned, DeleteName);
3279  }
3280 
3281  MarkFunctionReferenced(StartLoc, OperatorDelete);
3282 
3283  // Check access and ambiguity of destructor if we're going to call it.
3284  // Note that this is required even for a virtual delete.
3285  bool IsVirtualDelete = false;
3286  if (PointeeRD) {
3287  if (CXXDestructorDecl *Dtor = LookupDestructor(PointeeRD)) {
3288  CheckDestructorAccess(Ex.get()->getExprLoc(), Dtor,
3289  PDiag(diag::err_access_dtor) << PointeeElem);
3290  IsVirtualDelete = Dtor->isVirtual();
3291  }
3292  }
3293 
3294  diagnoseUnavailableAlignedAllocation(*OperatorDelete, StartLoc, true,
3295  *this);
3296 
3297  // Convert the operand to the type of the first parameter of operator
3298  // delete. This is only necessary if we selected a destroying operator
3299  // delete that we are going to call (non-virtually); converting to void*
3300  // is trivial and left to AST consumers to handle.
3301  QualType ParamType = OperatorDelete->getParamDecl(0)->getType();
3302  if (!IsVirtualDelete && !ParamType->getPointeeType()->isVoidType()) {
3303  Qualifiers Qs = Pointee.getQualifiers();
3304  if (Qs.hasCVRQualifiers()) {
3305  // Qualifiers are irrelevant to this conversion; we're only looking
3306  // for access and ambiguity.
3307  Qs.removeCVRQualifiers();
3308  QualType Unqual = Context.getPointerType(
3310  Ex = ImpCastExprToType(Ex.get(), Unqual, CK_NoOp);
3311  }
3312  Ex = PerformImplicitConversion(Ex.get(), ParamType, AA_Passing);
3313  if (Ex.isInvalid())
3314  return ExprError();
3315  }
3316  }
3317 
3319  Context.VoidTy, UseGlobal, ArrayForm, ArrayFormAsWritten,
3320  UsualArrayDeleteWantsSize, OperatorDelete, Ex.get(), StartLoc);
3321  AnalyzeDeleteExprMismatch(Result);
3322  return Result;
3323 }
3324 
3326  bool IsDelete, bool CallCanBeVirtual,
3327  bool WarnOnNonAbstractTypes,
3328  SourceLocation DtorLoc) {
3329  if (!dtor || dtor->isVirtual() || !CallCanBeVirtual || isUnevaluatedContext())
3330  return;
3331 
3332  // C++ [expr.delete]p3:
3333  // In the first alternative (delete object), if the static type of the
3334  // object to be deleted is different from its dynamic type, the static
3335  // type shall be a base class of the dynamic type of the object to be
3336  // deleted and the static type shall have a virtual destructor or the
3337  // behavior is undefined.
3338  //
3339  const CXXRecordDecl *PointeeRD = dtor->getParent();
3340  // Note: a final class cannot be derived from, no issue there
3341  if (!PointeeRD->isPolymorphic() || PointeeRD->hasAttr<FinalAttr>())
3342  return;
3343 
3344  // If the superclass is in a system header, there's nothing that can be done.
3345  // The `delete` (where we emit the warning) can be in a system header,
3346  // what matters for this warning is where the deleted type is defined.
3347  if (getSourceManager().isInSystemHeader(PointeeRD->getLocation()))
3348  return;
3349 
3350  QualType ClassType = dtor->getThisType(Context)->getPointeeType();
3351  if (PointeeRD->isAbstract()) {
3352  // If the class is abstract, we warn by default, because we're
3353  // sure the code has undefined behavior.
3354  Diag(Loc, diag::warn_delete_abstract_non_virtual_dtor) << (IsDelete ? 0 : 1)
3355  << ClassType;
3356  } else if (WarnOnNonAbstractTypes) {
3357  // Otherwise, if this is not an array delete, it's a bit suspect,
3358  // but not necessarily wrong.
3359  Diag(Loc, diag::warn_delete_non_virtual_dtor) << (IsDelete ? 0 : 1)
3360  << ClassType;
3361  }
3362  if (!IsDelete) {
3363  std::string TypeStr;
3364  ClassType.getAsStringInternal(TypeStr, getPrintingPolicy());
3365  Diag(DtorLoc, diag::note_delete_non_virtual)
3366  << FixItHint::CreateInsertion(DtorLoc, TypeStr + "::");
3367  }
3368 }
3369 
3371  SourceLocation StmtLoc,
3372  ConditionKind CK) {
3373  ExprResult E =
3374  CheckConditionVariable(cast<VarDecl>(ConditionVar), StmtLoc, CK);
3375  if (E.isInvalid())
3376  return ConditionError();
3377  return ConditionResult(*this, ConditionVar, MakeFullExpr(E.get(), StmtLoc),
3379 }
3380 
3381 /// \brief Check the use of the given variable as a C++ condition in an if,
3382 /// while, do-while, or switch statement.
3384  SourceLocation StmtLoc,
3385  ConditionKind CK) {
3386  if (ConditionVar->isInvalidDecl())
3387  return ExprError();
3388 
3389  QualType T = ConditionVar->getType();
3390 
3391  // C++ [stmt.select]p2:
3392  // The declarator shall not specify a function or an array.
3393  if (T->isFunctionType())
3394  return ExprError(Diag(ConditionVar->getLocation(),
3395  diag::err_invalid_use_of_function_type)
3396  << ConditionVar->getSourceRange());
3397  else if (T->isArrayType())
3398  return ExprError(Diag(ConditionVar->getLocation(),
3399  diag::err_invalid_use_of_array_type)
3400  << ConditionVar->getSourceRange());
3401 
3402  ExprResult Condition = DeclRefExpr::Create(
3403  Context, NestedNameSpecifierLoc(), SourceLocation(), ConditionVar,
3404  /*enclosing*/ false, ConditionVar->getLocation(),
3405  ConditionVar->getType().getNonReferenceType(), VK_LValue);
3406 
3407  MarkDeclRefReferenced(cast<DeclRefExpr>(Condition.get()));
3408 
3409  switch (CK) {
3411  return CheckBooleanCondition(StmtLoc, Condition.get());
3412 
3414  return CheckBooleanCondition(StmtLoc, Condition.get(), true);
3415 
3416  case ConditionKind::Switch:
3417  return CheckSwitchCondition(StmtLoc, Condition.get());
3418  }
3419 
3420  llvm_unreachable("unexpected condition kind");
3421 }
3422 
3423 /// CheckCXXBooleanCondition - Returns true if a conversion to bool is invalid.
3424 ExprResult Sema::CheckCXXBooleanCondition(Expr *CondExpr, bool IsConstexpr) {
3425  // C++ 6.4p4:
3426  // The value of a condition that is an initialized declaration in a statement
3427  // other than a switch statement is the value of the declared variable
3428  // implicitly converted to type bool. If that conversion is ill-formed, the
3429  // program is ill-formed.
3430  // The value of a condition that is an expression is the value of the
3431  // expression, implicitly converted to bool.
3432  //
3433  // FIXME: Return this value to the caller so they don't need to recompute it.
3434  llvm::APSInt Value(/*BitWidth*/1);
3435  return (IsConstexpr && !CondExpr->isValueDependent())
3436  ? CheckConvertedConstantExpression(CondExpr, Context.BoolTy, Value,
3439 }
3440 
3441 /// Helper function to determine whether this is the (deprecated) C++
3442 /// conversion from a string literal to a pointer to non-const char or
3443 /// non-const wchar_t (for narrow and wide string literals,
3444 /// respectively).
3445 bool
3447  // Look inside the implicit cast, if it exists.
3448  if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(From))
3449  From = Cast->getSubExpr();
3450 
3451  // A string literal (2.13.4) that is not a wide string literal can
3452  // be converted to an rvalue of type "pointer to char"; a wide
3453  // string literal can be converted to an rvalue of type "pointer
3454  // to wchar_t" (C++ 4.2p2).
3455  if (StringLiteral *StrLit = dyn_cast<StringLiteral>(From->IgnoreParens()))
3456  if (const PointerType *ToPtrType = ToType->getAs<PointerType>())
3457  if (const BuiltinType *ToPointeeType
3458  = ToPtrType->getPointeeType()->getAs<BuiltinType>()) {
3459  // This conversion is considered only when there is an
3460  // explicit appropriate pointer target type (C++ 4.2p2).
3461  if (!ToPtrType->getPointeeType().hasQualifiers()) {
3462  switch (StrLit->getKind()) {
3463  case StringLiteral::UTF8:
3464  case StringLiteral::UTF16:
3465  case StringLiteral::UTF32:
3466  // We don't allow UTF literals to be implicitly converted
3467  break;
3468  case StringLiteral::Ascii:
3469  return (ToPointeeType->getKind() == BuiltinType::Char_U ||
3470  ToPointeeType->getKind() == BuiltinType::Char_S);
3471  case StringLiteral::Wide:
3473  QualType(ToPointeeType, 0));
3474  }
3475  }
3476  }
3477 
3478  return false;
3479 }
3480 
3482  SourceLocation CastLoc,
3483  QualType Ty,
3484  CastKind Kind,
3485  CXXMethodDecl *Method,
3486  DeclAccessPair FoundDecl,
3487  bool HadMultipleCandidates,
3488  Expr *From) {
3489  switch (Kind) {
3490  default: llvm_unreachable("Unhandled cast kind!");
3491  case CK_ConstructorConversion: {
3492  CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Method);
3493  SmallVector<Expr*, 8> ConstructorArgs;
3494 
3495  if (S.RequireNonAbstractType(CastLoc, Ty,
3496  diag::err_allocation_of_abstract_type))
3497  return ExprError();
3498 
3499  if (S.CompleteConstructorCall(Constructor, From, CastLoc, ConstructorArgs))
3500  return ExprError();
3501 
3502  S.CheckConstructorAccess(CastLoc, Constructor, FoundDecl,
3504  if (S.DiagnoseUseOfDecl(Method, CastLoc))
3505  return ExprError();
3506 
3508  CastLoc, Ty, FoundDecl, cast<CXXConstructorDecl>(Method),
3509  ConstructorArgs, HadMultipleCandidates,
3510  /*ListInit*/ false, /*StdInitListInit*/ false, /*ZeroInit*/ false,
3512  if (Result.isInvalid())
3513  return ExprError();
3514 
3515  return S.MaybeBindToTemporary(Result.getAs<Expr>());
3516  }
3517 
3518  case CK_UserDefinedConversion: {
3519  assert(!From->getType()->isPointerType() && "Arg can't have pointer type!");
3520 
3521  S.CheckMemberOperatorAccess(CastLoc, From, /*arg*/ nullptr, FoundDecl);
3522  if (S.DiagnoseUseOfDecl(Method, CastLoc))
3523  return ExprError();
3524 
3525  // Create an implicit call expr that calls it.
3526  CXXConversionDecl *Conv = cast<CXXConversionDecl>(Method);
3527  ExprResult Result = S.BuildCXXMemberCallExpr(From, FoundDecl, Conv,
3528  HadMultipleCandidates);
3529  if (Result.isInvalid())
3530  return ExprError();
3531  // Record usage of conversion in an implicit cast.
3532  Result = ImplicitCastExpr::Create(S.Context, Result.get()->getType(),
3533  CK_UserDefinedConversion, Result.get(),
3534  nullptr, Result.get()->getValueKind());
3535 
3536  return S.MaybeBindToTemporary(Result.get());
3537  }
3538  }
3539 }
3540 
3541 /// PerformImplicitConversion - Perform an implicit conversion of the
3542 /// expression From to the type ToType using the pre-computed implicit
3543 /// conversion sequence ICS. Returns the converted
3544 /// expression. Action is the kind of conversion we're performing,
3545 /// used in the error message.
3546 ExprResult
3548  const ImplicitConversionSequence &ICS,
3549  AssignmentAction Action,
3550  CheckedConversionKind CCK) {
3551  switch (ICS.getKind()) {
3553  ExprResult Res = PerformImplicitConversion(From, ToType, ICS.Standard,
3554  Action, CCK);
3555  if (Res.isInvalid())
3556  return ExprError();
3557  From = Res.get();
3558  break;
3559  }
3560 
3562 
3565  QualType BeforeToType;
3566  assert(FD && "no conversion function for user-defined conversion seq");
3567  if (const CXXConversionDecl *Conv = dyn_cast<CXXConversionDecl>(FD)) {
3568  CastKind = CK_UserDefinedConversion;
3569 
3570  // If the user-defined conversion is specified by a conversion function,
3571  // the initial standard conversion sequence converts the source type to
3572  // the implicit object parameter of the conversion function.
3573  BeforeToType = Context.getTagDeclType(Conv->getParent());
3574  } else {
3575  const CXXConstructorDecl *Ctor = cast<CXXConstructorDecl>(FD);
3576  CastKind = CK_ConstructorConversion;
3577  // Do no conversion if dealing with ... for the first conversion.
3578  if (!ICS.UserDefined.EllipsisConversion) {
3579  // If the user-defined conversion is specified by a constructor, the
3580  // initial standard conversion sequence converts the source type to
3581  // the type required by the argument of the constructor
3582  BeforeToType = Ctor->getParamDecl(0)->getType().getNonReferenceType();
3583  }
3584  }
3585  // Watch out for ellipsis conversion.
3586  if (!ICS.UserDefined.EllipsisConversion) {
3587  ExprResult Res =
3588  PerformImplicitConversion(From, BeforeToType,
3590  CCK);
3591  if (Res.isInvalid())
3592  return ExprError();
3593  From = Res.get();
3594  }
3595 
3596  ExprResult CastArg
3597  = BuildCXXCastArgument(*this,
3598  From->getLocStart(),
3599  ToType.getNonReferenceType(),
3600  CastKind, cast<CXXMethodDecl>(FD),
3603  From);
3604 
3605  if (CastArg.isInvalid())
3606  return ExprError();
3607 
3608  From = CastArg.get();
3609 
3610  return PerformImplicitConversion(From, ToType, ICS.UserDefined.After,
3611  AA_Converting, CCK);
3612  }
3613 
3615  ICS.DiagnoseAmbiguousConversion(*this, From->getExprLoc(),
3616  PDiag(diag::err_typecheck_ambiguous_condition)
3617  << From->getSourceRange());
3618  return ExprError();
3619 
3621  llvm_unreachable("Cannot perform an ellipsis conversion");
3622 
3624  bool Diagnosed =
3626  From->getType(), From, Action);
3627  assert(Diagnosed && "failed to diagnose bad conversion"); (void)Diagnosed;
3628  return ExprError();
3629  }
3630 
3631  // Everything went well.
3632  return From;
3633 }
3634 
3635 /// PerformImplicitConversion - Perform an implicit conversion of the
3636 /// expression From to the type ToType by following the standard
3637 /// conversion sequence SCS. Returns the converted
3638 /// expression. Flavor is the context in which we're performing this
3639 /// conversion, for use in error messages.
3640 ExprResult
3642  const StandardConversionSequence& SCS,
3643  AssignmentAction Action,
3644  CheckedConversionKind CCK) {
3645  bool CStyle = (CCK == CCK_CStyleCast || CCK == CCK_FunctionalCast);
3646 
3647  // Overall FIXME: we are recomputing too many types here and doing far too
3648  // much extra work. What this means is that we need to keep track of more
3649  // information that is computed when we try the implicit conversion initially,
3650  // so that we don't need to recompute anything here.
3651  QualType FromType = From->getType();
3652 
3653  if (SCS.CopyConstructor) {
3654  // FIXME: When can ToType be a reference type?
3655  assert(!ToType->isReferenceType());
3656  if (SCS.Second == ICK_Derived_To_Base) {
3657  SmallVector<Expr*, 8> ConstructorArgs;
3658  if (CompleteConstructorCall(cast<CXXConstructorDecl>(SCS.CopyConstructor),
3659  From, /*FIXME:ConstructLoc*/SourceLocation(),
3660  ConstructorArgs))
3661  return ExprError();
3662  return BuildCXXConstructExpr(
3663  /*FIXME:ConstructLoc*/ SourceLocation(), ToType,
3665  ConstructorArgs, /*HadMultipleCandidates*/ false,
3666  /*ListInit*/ false, /*StdInitListInit*/ false, /*ZeroInit*/ false,
3668  }
3669  return BuildCXXConstructExpr(
3670  /*FIXME:ConstructLoc*/ SourceLocation(), ToType,
3672  From, /*HadMultipleCandidates*/ false,
3673  /*ListInit*/ false, /*StdInitListInit*/ false, /*ZeroInit*/ false,
3675  }
3676 
3677  // Resolve overloaded function references.
3678  if (Context.hasSameType(FromType, Context.OverloadTy)) {
3679  DeclAccessPair Found;
3681  true, Found);
3682  if (!Fn)
3683  return ExprError();
3684 
3685  if (DiagnoseUseOfDecl(Fn, From->getLocStart()))
3686  return ExprError();
3687 
3688  From = FixOverloadedFunctionReference(From, Found, Fn);
3689  FromType = From->getType();
3690  }
3691 
3692  // If we're converting to an atomic type, first convert to the corresponding
3693  // non-atomic type.
3694  QualType ToAtomicType;
3695  if (const AtomicType *ToAtomic = ToType->getAs<AtomicType>()) {
3696  ToAtomicType = ToType;
3697  ToType = ToAtomic->getValueType();
3698  }
3699 
3700  QualType InitialFromType = FromType;
3701  // Perform the first implicit conversion.
3702  switch (SCS.First) {
3703  case ICK_Identity:
3704  if (const AtomicType *FromAtomic = FromType->getAs<AtomicType>()) {
3705  FromType = FromAtomic->getValueType().getUnqualifiedType();
3706  From = ImplicitCastExpr::Create(Context, FromType, CK_AtomicToNonAtomic,
3707  From, /*BasePath=*/nullptr, VK_RValue);
3708  }
3709  break;
3710 
3711  case ICK_Lvalue_To_Rvalue: {
3712  assert(From->getObjectKind() != OK_ObjCProperty);
3713  ExprResult FromRes = DefaultLvalueConversion(From);
3714  assert(!FromRes.isInvalid() && "Can't perform deduced conversion?!");
3715  From = FromRes.get();
3716  FromType = From->getType();
3717  break;
3718  }
3719 
3720  case ICK_Array_To_Pointer:
3721  FromType = Context.getArrayDecayedType(FromType);
3722  From = ImpCastExprToType(From, FromType, CK_ArrayToPointerDecay,
3723  VK_RValue, /*BasePath=*/nullptr, CCK).get();
3724  break;
3725 
3727  FromType = Context.getPointerType(FromType);
3728  From = ImpCastExprToType(From, FromType, CK_FunctionToPointerDecay,
3729  VK_RValue, /*BasePath=*/nullptr, CCK).get();
3730  break;
3731 
3732  default:
3733  llvm_unreachable("Improper first standard conversion");
3734  }
3735 
3736  // Perform the second implicit conversion
3737  switch (SCS.Second) {
3738  case ICK_Identity:
3739  // C++ [except.spec]p5:
3740  // [For] assignment to and initialization of pointers to functions,
3741  // pointers to member functions, and references to functions: the
3742  // target entity shall allow at least the exceptions allowed by the
3743  // source value in the assignment or initialization.
3744  switch (Action) {
3745  case AA_Assigning:
3746  case AA_Initializing:
3747  // Note, function argument passing and returning are initialization.
3748  case AA_Passing:
3749  case AA_Returning:
3750  case AA_Sending:
3751  case AA_Passing_CFAudited:
3752  if (CheckExceptionSpecCompatibility(From, ToType))
3753  return ExprError();
3754  break;
3755 
3756  case AA_Casting:
3757  case AA_Converting:
3758  // Casts and implicit conversions are not initialization, so are not
3759  // checked for exception specification mismatches.
3760  break;
3761  }
3762  // Nothing else to do.
3763  break;
3764 
3767  if (ToType->isBooleanType()) {
3768  assert(FromType->castAs<EnumType>()->getDecl()->isFixed() &&
3769  SCS.Second == ICK_Integral_Promotion &&
3770  "only enums with fixed underlying type can promote to bool");
3771  From = ImpCastExprToType(From, ToType, CK_IntegralToBoolean,
3772  VK_RValue, /*BasePath=*/nullptr, CCK).get();
3773  } else {
3774  From = ImpCastExprToType(From, ToType, CK_IntegralCast,
3775  VK_RValue, /*BasePath=*/nullptr, CCK).get();
3776  }
3777  break;
3778 
3781  From = ImpCastExprToType(From, ToType, CK_FloatingCast,
3782  VK_RValue, /*BasePath=*/nullptr, CCK).get();
3783  break;
3784 
3785  case ICK_Complex_Promotion:
3786  case ICK_Complex_Conversion: {
3787  QualType FromEl = From->getType()->getAs<ComplexType>()->getElementType();
3788  QualType ToEl = ToType->getAs<ComplexType>()->getElementType();
3789  CastKind CK;
3790  if (FromEl->isRealFloatingType()) {
3791  if (ToEl->isRealFloatingType())
3792  CK = CK_FloatingComplexCast;
3793  else
3794  CK = CK_FloatingComplexToIntegralComplex;
3795  } else if (ToEl->isRealFloatingType()) {
3796  CK = CK_IntegralComplexToFloatingComplex;
3797  } else {
3798  CK = CK_IntegralComplexCast;
3799  }
3800  From = ImpCastExprToType(From, ToType, CK,
3801  VK_RValue, /*BasePath=*/nullptr, CCK).get();
3802  break;
3803  }
3804 
3805  case ICK_Floating_Integral:
3806  if (ToType->isRealFloatingType())
3807  From = ImpCastExprToType(From, ToType, CK_IntegralToFloating,
3808  VK_RValue, /*BasePath=*/nullptr, CCK).get();
3809  else
3810  From = ImpCastExprToType(From, ToType, CK_FloatingToIntegral,
3811  VK_RValue, /*BasePath=*/nullptr, CCK).get();
3812  break;
3813 
3815  From = ImpCastExprToType(From, ToType, CK_NoOp,
3816  VK_RValue, /*BasePath=*/nullptr, CCK).get();
3817  break;
3818 
3820  case ICK_Pointer_Conversion: {
3821  if (SCS.IncompatibleObjC && Action != AA_Casting) {
3822  // Diagnose incompatible Objective-C conversions
3823  if (Action == AA_Initializing || Action == AA_Assigning)
3824  Diag(From->getLocStart(),
3825  diag::ext_typecheck_convert_incompatible_pointer)
3826  << ToType << From->getType() << Action
3827  << From->getSourceRange() << 0;
3828  else
3829  Diag(From->getLocStart(),
3830  diag::ext_typecheck_convert_incompatible_pointer)
3831  << From->getType() << ToType << Action
3832  << From->getSourceRange() << 0;
3833 
3834  if (From->getType()->isObjCObjectPointerType() &&
3835  ToType->isObjCObjectPointerType())
3839  From->getType())) {
3840  if (Action == AA_Initializing)
3841  Diag(From->getLocStart(),
3842  diag::err_arc_weak_unavailable_assign);
3843  else
3844  Diag(From->getLocStart(),
3845  diag::err_arc_convesion_of_weak_unavailable)
3846  << (Action == AA_Casting) << From->getType() << ToType
3847  << From->getSourceRange();
3848  }
3849 
3850  CastKind Kind;
3851  CXXCastPath BasePath;
3852  if (CheckPointerConversion(From, ToType, Kind, BasePath, CStyle))
3853  return ExprError();
3854 
3855  // Make sure we extend blocks if necessary.
3856  // FIXME: doing this here is really ugly.
3857  if (Kind == CK_BlockPointerToObjCPointerCast) {
3858  ExprResult E = From;
3860  From = E.get();
3861  }
3862  if (getLangOpts().allowsNonTrivialObjCLifetimeQualifiers())
3863  CheckObjCConversion(SourceRange(), ToType, From, CCK);
3864  From = ImpCastExprToType(From, ToType, Kind, VK_RValue, &BasePath, CCK)
3865  .get();
3866  break;
3867  }
3868 
3869  case ICK_Pointer_Member: {
3870  CastKind Kind;
3871  CXXCastPath BasePath;
3872  if (CheckMemberPointerConversion(From, ToType, Kind, BasePath, CStyle))
3873  return ExprError();
3874  if (CheckExceptionSpecCompatibility(From, ToType))
3875  return ExprError();
3876 
3877  // We may not have been able to figure out what this member pointer resolved
3878  // to up until this exact point. Attempt to lock-in it's inheritance model.
3880  (void)isCompleteType(From->getExprLoc(), From->getType());
3881  (void)isCompleteType(From->getExprLoc(), ToType);
3882  }
3883 
3884  From = ImpCastExprToType(From, ToType, Kind, VK_RValue, &BasePath, CCK)
3885  .get();
3886  break;
3887  }
3888 
3890  // Perform half-to-boolean conversion via float.
3891  if (From->getType()->isHalfType()) {
3892  From = ImpCastExprToType(From, Context.FloatTy, CK_FloatingCast).get();
3893  FromType = Context.FloatTy;
3894  }
3895 
3896  From = ImpCastExprToType(From, Context.BoolTy,
3897  ScalarTypeToBooleanCastKind(FromType),
3898  VK_RValue, /*BasePath=*/nullptr, CCK).get();
3899  break;
3900 
3901  case ICK_Derived_To_Base: {
3902  CXXCastPath BasePath;
3904  ToType.getNonReferenceType(),
3905  From->getLocStart(),
3906  From->getSourceRange(),
3907  &BasePath,
3908  CStyle))
3909  return ExprError();
3910 
3911  From = ImpCastExprToType(From, ToType.getNonReferenceType(),
3912  CK_DerivedToBase, From->getValueKind(),
3913  &BasePath, CCK).get();
3914  break;
3915  }
3916 
3917  case ICK_Vector_Conversion:
3918  From = ImpCastExprToType(From, ToType, CK_BitCast,
3919  VK_RValue, /*BasePath=*/nullptr, CCK).get();
3920  break;
3921 
3922  case ICK_Vector_Splat: {
3923  // Vector splat from any arithmetic type to a vector.
3924  Expr *Elem = prepareVectorSplat(ToType, From).get();
3925  From = ImpCastExprToType(Elem, ToType, CK_VectorSplat, VK_RValue,
3926  /*BasePath=*/nullptr, CCK).get();
3927  break;
3928  }
3929 
3930  case ICK_Complex_Real:
3931  // Case 1. x -> _Complex y
3932  if (const ComplexType *ToComplex = ToType->getAs<ComplexType>()) {
3933  QualType ElType = ToComplex->getElementType();
3934  bool isFloatingComplex = ElType->isRealFloatingType();
3935 
3936  // x -> y
3937  if (Context.hasSameUnqualifiedType(ElType, From->getType())) {
3938  // do nothing
3939  } else if (From->getType()->isRealFloatingType()) {
3940  From = ImpCastExprToType(From, ElType,
3941  isFloatingComplex ? CK_FloatingCast : CK_FloatingToIntegral).get();
3942  } else {
3943  assert(From->getType()->isIntegerType());
3944  From = ImpCastExprToType(From, ElType,
3945  isFloatingComplex ? CK_IntegralToFloating : CK_IntegralCast).get();
3946  }
3947  // y -> _Complex y
3948  From = ImpCastExprToType(From, ToType,
3949  isFloatingComplex ? CK_FloatingRealToComplex
3950  : CK_IntegralRealToComplex).get();
3951 
3952  // Case 2. _Complex x -> y
3953  } else {
3954  const ComplexType *FromComplex = From->getType()->getAs<ComplexType>();
3955  assert(FromComplex);
3956 
3957  QualType ElType = FromComplex->getElementType();
3958  bool isFloatingComplex = ElType->isRealFloatingType();
3959 
3960  // _Complex x -> x
3961  From = ImpCastExprToType(From, ElType,
3962  isFloatingComplex ? CK_FloatingComplexToReal
3963  : CK_IntegralComplexToReal,
3964  VK_RValue, /*BasePath=*/nullptr, CCK).get();
3965 
3966  // x -> y
3967  if (Context.hasSameUnqualifiedType(ElType, ToType)) {
3968  // do nothing
3969  } else if (ToType->isRealFloatingType()) {
3970  From = ImpCastExprToType(From, ToType,
3971  isFloatingComplex ? CK_FloatingCast : CK_IntegralToFloating,
3972  VK_RValue, /*BasePath=*/nullptr, CCK).get();
3973  } else {
3974  assert(ToType->isIntegerType());
3975  From = ImpCastExprToType(From, ToType,
3976  isFloatingComplex ? CK_FloatingToIntegral : CK_IntegralCast,
3977  VK_RValue, /*BasePath=*/nullptr, CCK).get();
3978  }
3979  }
3980  break;
3981 
3983  From = ImpCastExprToType(From, ToType.getUnqualifiedType(), CK_BitCast,
3984  VK_RValue, /*BasePath=*/nullptr, CCK).get();
3985  break;
3986  }
3987 
3989  ExprResult FromRes = From;
3990  Sema::AssignConvertType ConvTy =
3992  if (FromRes.isInvalid())
3993  return ExprError();
3994  From = FromRes.get();
3995  assert ((ConvTy == Sema::Compatible) &&
3996  "Improper transparent union conversion");
3997  (void)ConvTy;
3998  break;
3999  }
4000 
4002  From = ImpCastExprToType(From, ToType,
4003  CK_ZeroToOCLEvent,
4004  From->getValueKind()).get();
4005  break;
4006 
4008  From = ImpCastExprToType(From, ToType,
4009  CK_ZeroToOCLQueue,
4010  From->getValueKind()).get();
4011  break;
4012 
4013  case ICK_Lvalue_To_Rvalue:
4014  case ICK_Array_To_Pointer:
4017  case ICK_Qualification:
4019  case ICK_C_Only_Conversion:
4021  llvm_unreachable("Improper second standard conversion");
4022  }
4023 
4024  switch (SCS.Third) {
4025  case ICK_Identity:
4026  // Nothing to do.
4027  break;
4028 
4030  // If both sides are functions (or pointers/references to them), there could
4031  // be incompatible exception declarations.
4032  if (CheckExceptionSpecCompatibility(From, ToType))
4033  return ExprError();
4034 
4035  From = ImpCastExprToType(From, ToType, CK_NoOp,
4036  VK_RValue, /*BasePath=*/nullptr, CCK).get();
4037  break;
4038 
4039  case ICK_Qualification: {
4040  // The qualification keeps the category of the inner expression, unless the
4041  // target type isn't a reference.
4042  ExprValueKind VK = ToType->isReferenceType() ?
4043  From->getValueKind() : VK_RValue;
4044  From = ImpCastExprToType(From, ToType.getNonLValueExprType(Context),
4045  CK_NoOp, VK, /*BasePath=*/nullptr, CCK).get();
4046 
4048  !getLangOpts().WritableStrings) {
4049  Diag(From->getLocStart(), getLangOpts().CPlusPlus11
4050  ? diag::ext_deprecated_string_literal_conversion
4051  : diag::warn_deprecated_string_literal_conversion)
4052  << ToType.getNonReferenceType();
4053  }
4054 
4055  break;
4056  }
4057 
4058  default:
4059  llvm_unreachable("Improper third standard conversion");
4060  }
4061 
4062  // If this conversion sequence involved a scalar -> atomic conversion, perform
4063  // that conversion now.
4064  if (!ToAtomicType.isNull()) {
4065  assert(Context.hasSameType(
4066  ToAtomicType->castAs<AtomicType>()->getValueType(), From->getType()));
4067  From = ImpCastExprToType(From, ToAtomicType, CK_NonAtomicToAtomic,
4068  VK_RValue, nullptr, CCK).get();
4069  }
4070 
4071  // If this conversion sequence succeeded and involved implicitly converting a
4072  // _Nullable type to a _Nonnull one, complain.
4073  if (CCK == CCK_ImplicitConversion)
4074  diagnoseNullableToNonnullConversion(ToType, InitialFromType,
4075  From->getLocStart());
4076 
4077  return From;
4078 }
4079 
4080 /// \brief Check the completeness of a type in a unary type trait.
4081 ///
4082 /// If the particular type trait requires a complete type, tries to complete
4083 /// it. If completing the type fails, a diagnostic is emitted and false
4084 /// returned. If completing the type succeeds or no completion was required,
4085 /// returns true.
4087  SourceLocation Loc,
4088  QualType ArgTy) {
4089  // C++0x [meta.unary.prop]p3:
4090  // For all of the class templates X declared in this Clause, instantiating
4091  // that template with a template argument that is a class template
4092  // specialization may result in the implicit instantiation of the template
4093  // argument if and only if the semantics of X require that the argument
4094  // must be a complete type.
4095  // We apply this rule to all the type trait expressions used to implement
4096  // these class templates. We also try to follow any GCC documented behavior
4097  // in these expressions to ensure portability of standard libraries.
4098  switch (UTT) {
4099  default: llvm_unreachable("not a UTT");
4100  // is_complete_type somewhat obviously cannot require a complete type.
4101  case UTT_IsCompleteType:
4102  // Fall-through
4103 
4104  // These traits are modeled on the type predicates in C++0x
4105  // [meta.unary.cat] and [meta.unary.comp]. They are not specified as
4106  // requiring a complete type, as whether or not they return true cannot be
4107  // impacted by the completeness of the type.
4108  case UTT_IsVoid:
4109  case UTT_IsIntegral:
4110  case UTT_IsFloatingPoint:
4111  case UTT_IsArray:
4112  case UTT_IsPointer:
4113  case UTT_IsLvalueReference:
4114  case UTT_IsRvalueReference:
4117  case UTT_IsEnum:
4118  case UTT_IsUnion:
4119  case UTT_IsClass:
4120  case UTT_IsFunction:
4121  case UTT_IsReference:
4122  case UTT_IsArithmetic:
4123  case UTT_IsFundamental:
4124  case UTT_IsObject:
4125  case UTT_IsScalar:
4126  case UTT_IsCompound:
4127  case UTT_IsMemberPointer:
4128  // Fall-through
4129 
4130  // These traits are modeled on type predicates in C++0x [meta.unary.prop]
4131  // which requires some of its traits to have the complete type. However,
4132  // the completeness of the type cannot impact these traits' semantics, and
4133  // so they don't require it. This matches the comments on these traits in
4134  // Table 49.
4135  case UTT_IsConst:
4136  case UTT_IsVolatile:
4137  case UTT_IsSigned:
4138  case UTT_IsUnsigned:
4139 
4140  // This type trait always returns false, checking the type is moot.
4141  case UTT_IsInterfaceClass:
4142  return true;
4143 
4144  // C++14 [meta.unary.prop]:
4145  // If T is a non-union class type, T shall be a complete type.
4146  case UTT_IsEmpty:
4147  case UTT_IsPolymorphic:
4148  case UTT_IsAbstract:
4149  if (const auto *RD = ArgTy->getAsCXXRecordDecl())
4150  if (!RD->isUnion())
4151  return !S.RequireCompleteType(
4152  Loc, ArgTy, diag::err_incomplete_type_used_in_type_trait_expr);
4153  return true;
4154 
4155  // C++14 [meta.unary.prop]:
4156  // If T is a class type, T shall be a complete type.
4157  case UTT_IsFinal:
4158  case UTT_IsSealed:
4159  if (ArgTy->getAsCXXRecordDecl())
4160  return !S.RequireCompleteType(
4161  Loc, ArgTy, diag::err_incomplete_type_used_in_type_trait_expr);
4162  return true;
4163 
4164  // C++1z [meta.unary.prop]:
4165  // remove_all_extents_t<T> shall be a complete type or cv void.
4166  case UTT_IsAggregate:
4167  case UTT_IsTrivial:
4169  case UTT_IsStandardLayout:
4170  case UTT_IsPOD:
4171  case UTT_IsLiteral:
4172  // Per the GCC type traits documentation, T shall be a complete type, cv void,
4173  // or an array of unknown bound. But GCC actually imposes the same constraints
4174  // as above.
4175  case UTT_HasNothrowAssign:
4178  case UTT_HasNothrowCopy:
4179  case UTT_HasTrivialAssign:
4183  case UTT_HasTrivialCopy:
4186  ArgTy = QualType(ArgTy->getBaseElementTypeUnsafe(), 0);
4187  LLVM_FALLTHROUGH;
4188 
4189  // C++1z [meta.unary.prop]:
4190  // T shall be a complete type, cv void, or an array of unknown bound.
4191  case UTT_IsDestructible:
4195  if (ArgTy->isIncompleteArrayType() || ArgTy->isVoidType())
4196  return true;
4197 
4198  return !S.RequireCompleteType(
4199  Loc, ArgTy, diag::err_incomplete_type_used_in_type_trait_expr);
4200  }
4201 }
4202 
4204  Sema &Self, SourceLocation KeyLoc, ASTContext &C,
4205  bool (CXXRecordDecl::*HasTrivial)() const,
4206  bool (CXXRecordDecl::*HasNonTrivial)() const,
4207  bool (CXXMethodDecl::*IsDesiredOp)() const)
4208 {
4209  CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
4210  if ((RD->*HasTrivial)() && !(RD->*HasNonTrivial)())
4211  return true;
4212 
4214  DeclarationNameInfo NameInfo(Name, KeyLoc);
4215  LookupResult Res(Self, NameInfo, Sema::LookupOrdinaryName);
4216  if (Self.LookupQualifiedName(Res, RD)) {
4217  bool FoundOperator = false;
4218  Res.suppressDiagnostics();
4219  for (LookupResult::iterator Op = Res.begin(), OpEnd = Res.end();
4220  Op != OpEnd; ++Op) {
4221  if (isa<FunctionTemplateDecl>(*Op))
4222  continue;
4223 
4224  CXXMethodDecl *Operator = cast<CXXMethodDecl>(*Op);
4225  if((Operator->*IsDesiredOp)()) {
4226  FoundOperator = true;
4227  const FunctionProtoType *CPT =
4228  Operator->getType()->getAs<FunctionProtoType>();
4229  CPT = Self.ResolveExceptionSpec(KeyLoc, CPT);
4230  if (!CPT || !CPT->isNothrow(C))
4231  return false;
4232  }
4233  }
4234  return FoundOperator;
4235  }
4236  return false;
4237 }
4238 
4239 static bool EvaluateUnaryTypeTrait(Sema &Self, TypeTrait UTT,
4240  SourceLocation KeyLoc, QualType T) {
4241  assert(!T->isDependentType() && "Cannot evaluate traits of dependent type");
4242 
4243  ASTContext &C = Self.Context;
4244  switch(UTT) {
4245  default: llvm_unreachable("not a UTT");
4246  // Type trait expressions corresponding to the primary type category
4247  // predicates in C++0x [meta.unary.cat].
4248  case UTT_IsVoid:
4249  return T->isVoidType();
4250  case UTT_IsIntegral:
4251  return T->isIntegralType(C);
4252  case UTT_IsFloatingPoint:
4253  return T->isFloatingType();
4254  case UTT_IsArray:
4255  return T->isArrayType();
4256  case UTT_IsPointer:
4257  return T->isPointerType();
4258  case UTT_IsLvalueReference:
4259  return T->isLValueReferenceType();
4260  case UTT_IsRvalueReference:
4261  return T->isRValueReferenceType();
4263  return T->isMemberFunctionPointerType();
4265  return T->isMemberDataPointerType();
4266  case UTT_IsEnum:
4267  return T->isEnumeralType();
4268  case UTT_IsUnion:
4269  return T->isUnionType();
4270  case UTT_IsClass:
4271  return T->isClassType() || T->isStructureType() || T->isInterfaceType();
4272  case UTT_IsFunction:
4273  return T->isFunctionType();
4274 
4275  // Type trait expressions which correspond to the convenient composition
4276  // predicates in C++0x [meta.unary.comp].
4277  case UTT_IsReference:
4278  return T->isReferenceType();
4279  case UTT_IsArithmetic:
4280  return T->isArithmeticType() && !T->isEnumeralType();
4281  case UTT_IsFundamental:
4282  return T->isFundamentalType();
4283  case UTT_IsObject:
4284  return T->isObjectType();
4285  case UTT_IsScalar:
4286  // Note: semantic analysis depends on Objective-C lifetime types to be
4287  // considered scalar types. However, such types do not actually behave
4288  // like scalar types at run time (since they may require retain/release
4289  // operations), so we report them as non-scalar.
4290  if (T->isObjCLifetimeType()) {
4291  switch (T.getObjCLifetime()) {
4292  case Qualifiers::OCL_None:
4294  return true;
4295 
4297  case Qualifiers::OCL_Weak:
4299  return false;
4300  }
4301  }
4302 
4303  return T->isScalarType();
4304  case UTT_IsCompound:
4305  return T->isCompoundType();
4306  case UTT_IsMemberPointer:
4307  return T->isMemberPointerType();
4308 
4309  // Type trait expressions which correspond to the type property predicates
4310  // in C++0x [meta.unary.prop].
4311  case UTT_IsConst:
4312  return T.isConstQualified();
4313  case UTT_IsVolatile:
4314  return T.isVolatileQualified();
4315  case UTT_IsTrivial:
4316  return T.isTrivialType(C);
4318  return T.isTriviallyCopyableType(C);
4319  case UTT_IsStandardLayout:
4320  return T->isStandardLayoutType();
4321  case UTT_IsPOD:
4322  return T.isPODType(C);
4323  case UTT_IsLiteral:
4324  return T->isLiteralType(C);
4325  case UTT_IsEmpty:
4326  if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
4327  return !RD->isUnion() && RD->isEmpty();
4328  return false;
4329  case UTT_IsPolymorphic:
4330  if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
4331  return !RD->isUnion() && RD->isPolymorphic();
4332  return false;
4333  case UTT_IsAbstract:
4334  if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
4335  return !RD->isUnion() && RD->isAbstract();
4336  return false;
4337  case UTT_IsAggregate:
4338  // Report vector extensions and complex types as aggregates because they
4339  // support aggregate initialization. GCC mirrors this behavior for vectors
4340  // but not _Complex.
4341  return T->isAggregateType() || T->isVectorType() || T->isExtVectorType() ||
4342  T->isAnyComplexType();
4343  // __is_interface_class only returns true when CL is invoked in /CLR mode and
4344  // even then only when it is used with the 'interface struct ...' syntax
4345  // Clang doesn't support /CLR which makes this type trait moot.
4346  case UTT_IsInterfaceClass:
4347  return false;
4348  case UTT_IsFinal:
4349  case UTT_IsSealed:
4350  if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
4351  return RD->hasAttr<FinalAttr>();
4352  return false;
4353  case UTT_IsSigned:
4354  return T->isSignedIntegerType();
4355  case UTT_IsUnsigned:
4356  return T->isUnsignedIntegerType();
4357 
4358  // Type trait expressions which query classes regarding their construction,
4359  // destruction, and copying. Rather than being based directly on the
4360  // related type predicates in the standard, they are specified by both
4361  // GCC[1] and the Embarcadero C++ compiler[2], and Clang implements those
4362  // specifications.
4363  //
4364  // 1: http://gcc.gnu/.org/onlinedocs/gcc/Type-Traits.html
4365  // 2: http://docwiki.embarcadero.com/RADStudio/XE/en/Type_Trait_Functions_(C%2B%2B0x)_Index
4366  //
4367  // Note that these builtins do not behave as documented in g++: if a class
4368  // has both a trivial and a non-trivial special member of a particular kind,
4369  // they return false! For now, we emulate this behavior.
4370  // FIXME: This appears to be a g++ bug: more complex cases reveal that it
4371  // does not correctly compute triviality in the presence of multiple special
4372  // members of the same kind. Revisit this once the g++ bug is fixed.
4374  // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
4375  // If __is_pod (type) is true then the trait is true, else if type is
4376  // a cv class or union type (or array thereof) with a trivial default
4377  // constructor ([class.ctor]) then the trait is true, else it is false.
4378  if (T.isPODType(C))
4379  return true;
4380  if (CXXRecordDecl *RD = C.getBaseElementType(T)->getAsCXXRecordDecl())
4381  return RD->hasTrivialDefaultConstructor() &&
4382  !RD->hasNonTrivialDefaultConstructor();
4383  return false;
4385  // This trait is implemented by MSVC 2012 and needed to parse the
4386  // standard library headers. Specifically this is used as the logic
4387  // behind std::is_trivially_move_constructible (20.9.4.3).
4388  if (T.isPODType(C))
4389  return true;
4390  if (CXXRecordDecl *RD = C.getBaseElementType(T)->getAsCXXRecordDecl())
4391  return RD->hasTrivialMoveConstructor() && !RD->hasNonTrivialMoveConstructor();
4392  return false;
4393  case UTT_HasTrivialCopy:
4394  // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
4395  // If __is_pod (type) is true or type is a reference type then
4396  // the trait is true, else if type is a cv class or union type
4397  // with a trivial copy constructor ([class.copy]) then the trait
4398  // is true, else it is false.
4399  if (T.isPODType(C) || T->isReferenceType())
4400  return true;
4401  if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
4402  return RD->hasTrivialCopyConstructor() &&
4403  !RD->hasNonTrivialCopyConstructor();
4404  return false;
4406  // This trait is implemented by MSVC 2012 and needed to parse the
4407  // standard library headers. Specifically it is used as the logic
4408  // behind std::is_trivially_move_assignable (20.9.4.3)
4409  if (T.isPODType(C))
4410  return true;
4411  if (CXXRecordDecl *RD = C.getBaseElementType(T)->getAsCXXRecordDecl())
4412  return RD->hasTrivialMoveAssignment() && !RD->hasNonTrivialMoveAssignment();
4413  return false;
4414  case UTT_HasTrivialAssign:
4415  // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
4416  // If type is const qualified or is a reference type then the
4417  // trait is false. Otherwise if __is_pod (type) is true then the
4418  // trait is true, else if type is a cv class or union type with
4419  // a trivial copy assignment ([class.copy]) then the trait is
4420  // true, else it is false.
4421  // Note: the const and reference restrictions are interesting,
4422  // given that const and reference members don't prevent a class
4423  // from having a trivial copy assignment operator (but do cause
4424  // errors if the copy assignment operator is actually used, q.v.
4425  // [class.copy]p12).
4426 
4427  if (T.isConstQualified())
4428  return false;
4429  if (T.isPODType(C))
4430  return true;
4431  if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
4432  return RD->hasTrivialCopyAssignment() &&
4433  !RD->hasNonTrivialCopyAssignment();
4434  return false;
4435  case UTT_IsDestructible:
4438  // C++14 [meta.unary.prop]:
4439  // For reference types, is_destructible<T>::value is true.
4440  if (T->isReferenceType())
4441  return true;
4442 
4443  // Objective-C++ ARC: autorelease types don't require destruction.
4444  if (T->isObjCLifetimeType() &&
4446  return true;
4447 
4448  // C++14 [meta.unary.prop]:
4449  // For incomplete types and function types, is_destructible<T>::value is
4450  // false.
4451  if (T->isIncompleteType() || T->isFunctionType())
4452  return false;
4453 
4454  // A type that requires destruction (via a non-trivial destructor or ARC
4455  // lifetime semantics) is not trivially-destructible.
4457  return false;
4458 
4459  // C++14 [meta.unary.prop]:
4460  // For object types and given U equal to remove_all_extents_t<T>, if the
4461  // expression std::declval<U&>().~U() is well-formed when treated as an
4462  // unevaluated operand (Clause 5), then is_destructible<T>::value is true
4463  if (auto *RD = C.getBaseElementType(T)->getAsCXXRecordDecl()) {
4464  CXXDestructorDecl *Destructor = Self.LookupDestructor(RD);
4465  if (!Destructor)
4466  return false;
4467  // C++14 [dcl.fct.def.delete]p2:
4468  // A program that refers to a deleted function implicitly or
4469  // explicitly, other than to declare it, is ill-formed.
4470  if (Destructor->isDeleted())
4471  return false;
4472  if (C.getLangOpts().AccessControl && Destructor->getAccess() != AS_public)
4473  return false;
4474  if (UTT == UTT_IsNothrowDestructible) {
4475  const FunctionProtoType *CPT =
4476  Destructor->getType()->getAs<FunctionProtoType>();
4477  CPT = Self.ResolveExceptionSpec(KeyLoc, CPT);
4478  if (!CPT || !CPT->isNothrow(C))
4479  return false;
4480  }
4481  }
4482  return true;
4483 
4485  // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html
4486  // If __is_pod (type) is true or type is a reference type
4487  // then the trait is true, else if type is a cv class or union
4488  // type (or array thereof) with a trivial destructor
4489  // ([class.dtor]) then the trait is true, else it is
4490  // false.
4491  if (T.isPODType(C) || T->isReferenceType())
4492  return true;
4493 
4494  // Objective-C++ ARC: autorelease types don't require destruction.
4495  if (T->isObjCLifetimeType() &&
4497  return true;
4498 
4499  if (CXXRecordDecl *RD = C.getBaseElementType(T)->getAsCXXRecordDecl())
4500  return RD->hasTrivialDestructor();
4501  return false;
4502  // TODO: Propagate nothrowness for implicitly declared special members.
4503  case UTT_HasNothrowAssign:
4504  // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
4505  // If type is const qualified or is a reference type then the
4506  // trait is false. Otherwise if __has_trivial_assign (type)
4507  // is true then the trait is true, else if type is a cv class
4508  // or union type with copy assignment operators that are known
4509  // not to throw an exception then the trait is true, else it is
4510  // false.
4511  if (C.getBaseElementType(T).isConstQualified())
4512  return false;
4513  if (T->isReferenceType())
4514  return false;
4515  if (T.isPODType(C) || T->isObjCLifetimeType())
4516  return true;
4517 
4518  if (const RecordType *RT = T->getAs<RecordType>())
4519  return HasNoThrowOperator(RT, OO_Equal, Self, KeyLoc, C,
4523  return false;
4525  // This trait is implemented by MSVC 2012 and needed to parse the
4526  // standard library headers. Specifically this is used as the logic
4527  // behind std::is_nothrow_move_assignable (20.9.4.3).
4528  if (T.isPODType(C))
4529  return true;
4530 
4531  if (const RecordType *RT = C.getBaseElementType(T)->getAs<RecordType>())
4532  return HasNoThrowOperator(RT, OO_Equal, Self, KeyLoc, C,
4536  return false;
4537  case UTT_HasNothrowCopy:
4538  // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
4539  // If __has_trivial_copy (type) is true then the trait is true, else
4540  // if type is a cv class or union type with copy constructors that are
4541  // known not to throw an exception then the trait is true, else it is
4542  // false.
4543  if (T.isPODType(C) || T->isReferenceType() || T->isObjCLifetimeType())
4544  return true;
4545  if (CXXRecordDecl *RD = T->getAsCXXRecordDecl()) {
4546  if (RD->hasTrivialCopyConstructor() &&
4547  !RD->hasNonTrivialCopyConstructor())
4548  return true;
4549 
4550  bool FoundConstructor = false;
4551  unsigned FoundTQs;
4552  for (const auto *ND : Self.LookupConstructors(RD)) {
4553  // A template constructor is never a copy constructor.
4554  // FIXME: However, it may actually be selected at the actual overload
4555  // resolution point.
4556  if (isa<FunctionTemplateDecl>(ND->getUnderlyingDecl()))
4557  continue;
4558  // UsingDecl itself is not a constructor
4559  if (isa<UsingDecl>(ND))
4560  continue;
4561  auto *Constructor = cast<CXXConstructorDecl>(ND->getUnderlyingDecl());
4562  if (Constructor->isCopyConstructor(FoundTQs)) {
4563  FoundConstructor = true;
4564  const FunctionProtoType *CPT
4565  = Constructor->getType()->getAs<FunctionProtoType>();
4566  CPT = Self.ResolveExceptionSpec(KeyLoc, CPT);
4567  if (!CPT)
4568  return false;
4569  // TODO: check whether evaluating default arguments can throw.
4570  // For now, we'll be conservative and assume that they can throw.
4571  if (!CPT->isNothrow(C) || CPT->getNumParams() > 1)
4572  return false;
4573  }
4574  }
4575 
4576  return FoundConstructor;
4577  }
4578  return false;
4580  // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html
4581  // If __has_trivial_constructor (type) is true then the trait is
4582  // true, else if type is a cv class or union type (or array
4583  // thereof) with a default constructor that is known not to
4584  // throw an exception then the trait is true, else it is false.
4585  if (T.isPODType(C) || T->isObjCLifetimeType())
4586  return true;
4587  if (CXXRecordDecl *RD = C.getBaseElementType(T)->getAsCXXRecordDecl()) {
4588  if (RD->hasTrivialDefaultConstructor() &&
4589  !RD->hasNonTrivialDefaultConstructor())
4590  return true;
4591 
4592  bool FoundConstructor = false;
4593  for (const auto *ND : Self.LookupConstructors(RD)) {
4594  // FIXME: In C++0x, a constructor template can be a default constructor.
4595  if (isa<FunctionTemplateDecl>(ND->getUnderlyingDecl()))
4596  continue;
4597  // UsingDecl itself is not a constructor
4598  if (isa<UsingDecl>(ND))
4599  continue;
4600  auto *Constructor = cast<CXXConstructorDecl>(ND->getUnderlyingDecl());
4601  if (Constructor->isDefaultConstructor()) {
4602  FoundConstructor = true;
4603  const FunctionProtoType *CPT
4604  = Constructor->getType()->getAs<FunctionProtoType>();
4605  CPT = Self.ResolveExceptionSpec(KeyLoc, CPT);
4606  if (!CPT)
4607  return false;
4608  // FIXME: check whether evaluating default arguments can throw.
4609  // For now, we'll be conservative and assume that they can throw.
4610  if (!CPT->isNothrow(C) || CPT->getNumParams() > 0)
4611  return false;
4612  }
4613  }
4614  return FoundConstructor;
4615  }
4616  return false;
4618  // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
4619  // If type is a class type with a virtual destructor ([class.dtor])
4620  // then the trait is true, else it is false.
4621  if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
4622  if (CXXDestructorDecl *Destructor = Self.LookupDestructor(RD))
4623  return Destructor->isVirtual();
4624  return false;
4625 
4626  // These type trait expressions are modeled on the specifications for the
4627  // Embarcadero C++0x type trait functions:
4628  // http://docwiki.embarcadero.com/RADStudio/XE/en/Type_Trait_Functions_(C%2B%2B0x)_Index
4629  case UTT_IsCompleteType:
4630  // http://docwiki.embarcadero.com/RADStudio/XE/en/Is_complete_type_(typename_T_):
4631  // Returns True if and only if T is a complete type at the point of the
4632  // function call.
4633  return !T->isIncompleteType();
4635  return C.hasUniqueObjectRepresentations(T);
4636  }
4637 }
4638 
4639 static bool EvaluateBinaryTypeTrait(Sema &Self, TypeTrait BTT, QualType LhsT,
4640  QualType RhsT, SourceLocation KeyLoc);
4641 
4644  SourceLocation RParenLoc) {
4645  if (Kind <= UTT_Last)
4646  return EvaluateUnaryTypeTrait(S, Kind, KWLoc, Args[0]->getType());
4647 
4648  if (Kind <= BTT_Last)
4649  return EvaluateBinaryTypeTrait(S, Kind, Args[0]->getType(),
4650  Args[1]->getType(), RParenLoc);
4651 
4652  switch (Kind) {
4656  // C++11 [meta.unary.prop]:
4657  // is_trivially_constructible is defined as:
4658  //
4659  // is_constructible<T, Args...>::value is true and the variable
4660  // definition for is_constructible, as defined below, is known to call
4661  // no operation that is not trivial.
4662  //
4663  // The predicate condition for a template specialization
4664  // is_constructible<T, Args...> shall be satisfied if and only if the
4665  // following variable definition would be well-formed for some invented
4666  // variable t:
4667  //
4668  // T t(create<Args>()...);
4669  assert(!Args.empty());
4670 
4671  // Precondition: T and all types in the parameter pack Args shall be
4672  // complete types, (possibly cv-qualified) void, or arrays of
4673  // unknown bound.
4674  for (const auto *TSI : Args) {
4675  QualType ArgTy = TSI->getType();
4676  if (ArgTy->isVoidType() || ArgTy->isIncompleteArrayType())
4677  continue;
4678 
4679  if (S.RequireCompleteType(KWLoc, ArgTy,
4680  diag::err_incomplete_type_used_in_type_trait_expr))
4681  return false;
4682  }
4683 
4684  // Make sure the first argument is not incomplete nor a function type.
4685  QualType T = Args[0]->getType();
4686  if (T->isIncompleteType() || T->isFunctionType())
4687  return false;
4688 
4689  // Make sure the first argument is not an abstract type.
4690  CXXRecordDecl *RD = T->getAsCXXRecordDecl();
4691  if (RD && RD->isAbstract())
4692  return false;
4693 
4694  SmallVector<OpaqueValueExpr, 2> OpaqueArgExprs;
4695  SmallVector<Expr *, 2> ArgExprs;
4696  ArgExprs.reserve(Args.size() - 1);
4697  for (unsigned I = 1, N = Args.size(); I != N; ++I) {
4698  QualType ArgTy = Args[I]->getType();
4699  if (ArgTy->isObjectType() || ArgTy->isFunctionType())
4700  ArgTy = S.Context.getRValueReferenceType(ArgTy);
4701  OpaqueArgExprs.push_back(
4702  OpaqueValueExpr(Args[I]->getTypeLoc().getLocStart(),
4703  ArgTy.getNonLValueExprType(S.Context),
4704  Expr::getValueKindForType(ArgTy)));
4705  }
4706  for (Expr &E : OpaqueArgExprs)
4707  ArgExprs.push_back(&E);
4708 
4709  // Perform the initialization in an unevaluated context within a SFINAE
4710  // trap at translation unit scope.
4713  Sema::SFINAETrap SFINAE(S, /*AccessCheckingSFINAE=*/true);
4717  RParenLoc));
4718  InitializationSequence Init(S, To, InitKind, ArgExprs);
4719  if (Init.Failed())
4720  return false;
4721 
4722  ExprResult Result = Init.Perform(S, To, InitKind, ArgExprs);
4723  if (Result.isInvalid() || SFINAE.hasErrorOccurred())
4724  return false;
4725 
4726  if (Kind == clang::TT_IsConstructible)
4727  return true;
4728 
4730  return S.canThrow(Result.get()) == CT_Cannot;
4731 
4732  if (Kind == clang::TT_IsTriviallyConstructible) {
4733  // Under Objective-C ARC and Weak, if the destination has non-trivial
4734  // Objective-C lifetime, this is a non-trivial construction.
4736  return false;
4737 
4738  // The initialization succeeded; now make sure there are no non-trivial
4739  // calls.
4740  return !Result.get()->hasNonTrivialCall(S.Context);
4741  }
4742 
4743  llvm_unreachable("unhandled type trait");
4744  return false;
4745  }
4746  default: llvm_unreachable("not a TT");
4747  }
4748 
4749  return false;
4750 }
4751 
4754  SourceLocation RParenLoc) {
4755  QualType ResultType = Context.getLogicalOperationType();
4756 
4758  *this, Kind, KWLoc, Args[0]->getType()))
4759  return ExprError();
4760 
4761  bool Dependent = false;
4762  for (unsigned I = 0, N = Args.size(); I != N; ++I) {
4763  if (Args[I]->getType()->isDependentType()) {
4764  Dependent = true;
4765  break;
4766  }
4767  }
4768 
4769  bool Result = false;
4770  if (!Dependent)
4771  Result = evaluateTypeTrait(*this, Kind, KWLoc, Args, RParenLoc);
4772 
4773  return TypeTraitExpr::Create(Context, ResultType, KWLoc, Kind, Args,
4774  RParenLoc, Result);
4775 }
4776 
4778  ArrayRef<ParsedType> Args,
4779  SourceLocation RParenLoc) {
4780  SmallVector<TypeSourceInfo *, 4> ConvertedArgs;
4781  ConvertedArgs.reserve(Args.size());
4782 
4783  for (unsigned I = 0, N = Args.size(); I != N; ++I) {
4784  TypeSourceInfo *TInfo;
4785  QualType T = GetTypeFromParser(Args[I], &TInfo);
4786  if (!TInfo)
4787  TInfo = Context.getTrivialTypeSourceInfo(T, KWLoc);
4788 
4789  ConvertedArgs.push_back(TInfo);
4790  }
4791 
4792  return BuildTypeTrait(Kind, KWLoc, ConvertedArgs, RParenLoc);
4793 }
4794 
4795 static bool EvaluateBinaryTypeTrait(Sema &Self, TypeTrait BTT, QualType LhsT,
4796  QualType RhsT, SourceLocation KeyLoc) {
4797  assert(!LhsT->isDependentType() && !RhsT->isDependentType() &&
4798  "Cannot evaluate traits of dependent types");
4799 
4800  switch(BTT) {
4801  case BTT_IsBaseOf: {
4802  // C++0x [meta.rel]p2
4803  // Base is a base class of Derived without regard to cv-qualifiers or
4804  // Base and Derived are not unions and name the same class type without
4805  // regard to cv-qualifiers.
4806 
4807  const RecordType *lhsRecord = LhsT->getAs<RecordType>();
4808  const RecordType *rhsRecord = RhsT->getAs<RecordType>();
4809  if (!rhsRecord || !lhsRecord) {
4810  const ObjCObjectType *LHSObjTy = LhsT->getAs<ObjCObjectType>();
4811  const ObjCObjectType *RHSObjTy = RhsT->getAs<ObjCObjectType>();
4812  if (!LHSObjTy || !RHSObjTy)
4813  return false;
4814 
4815  ObjCInterfaceDecl *BaseInterface = LHSObjTy->getInterface();
4816  ObjCInterfaceDecl *DerivedInterface = RHSObjTy->getInterface();
4817  if (!BaseInterface || !DerivedInterface)
4818  return false;
4819 
4820  if (Self.RequireCompleteType(
4821  KeyLoc, RhsT, diag::err_incomplete_type_used_in_type_trait_expr))
4822  return false;
4823 
4824  return BaseInterface->isSuperClassOf(DerivedInterface);
4825  }
4826 
4827  assert(Self.Context.hasSameUnqualifiedType(LhsT, RhsT)
4828  == (lhsRecord == rhsRecord));
4829 
4830  if (lhsRecord == rhsRecord)
4831  return !lhsRecord->getDecl()->isUnion();
4832 
4833  // C++0x [meta.rel]p2:
4834  // If Base and Derived are class types and are different types
4835  // (ignoring possible cv-qualifiers) then Derived shall be a
4836  // complete type.
4837  if (Self.RequireCompleteType(KeyLoc, RhsT,
4838  diag::err_incomplete_type_used_in_type_trait_expr))
4839  return false;
4840 
4841  return cast<CXXRecordDecl>(rhsRecord->getDecl())
4842  ->isDerivedFrom(cast<CXXRecordDecl>(lhsRecord->getDecl()));
4843  }
4844  case BTT_IsSame:
4845  return Self.Context.hasSameType(LhsT, RhsT);
4846  case BTT_TypeCompatible: {
4847  // GCC ignores cv-qualifiers on arrays for this builtin.
4848  Qualifiers LhsQuals, RhsQuals;
4849  QualType Lhs = Self.getASTContext().getUnqualifiedArrayType(LhsT, LhsQuals);
4850  QualType Rhs = Self.getASTContext().getUnqualifiedArrayType(RhsT, RhsQuals);
4851  return Self.Context.typesAreCompatible(Lhs, Rhs);
4852  }
4853  case BTT_IsConvertible:
4854  case BTT_IsConvertibleTo: {
4855  // C++0x [meta.rel]p4:
4856  // Given the following function prototype:
4857  //
4858  // template <class T>
4859  // typename add_rvalue_reference<T>::type create();
4860  //
4861  // the predicate condition for a template specialization
4862  // is_convertible<From, To> shall be satisfied if and only if
4863  // the return expression in the following code would be
4864  // well-formed, including any implicit conversions to the return
4865  // type of the function:
4866  //
4867  // To test() {
4868  // return create<From>();
4869  // }
4870  //
4871  // Access checking is performed as if in a context unrelated to To and
4872  // From. Only the validity of the immediate context of the expression
4873  // of the return-statement (including conversions to the return type)
4874  // is considered.
4875  //
4876  // We model the initialization as a copy-initialization of a temporary
4877  // of the appropriate type, which for this expression is identical to the
4878  // return statement (since NRVO doesn't apply).
4879 
4880  // Functions aren't allowed to return function or array types.
4881  if (RhsT->isFunctionType() || RhsT->isArrayType())
4882  return false;
4883 
4884  // A return statement in a void function must have void type.
4885  if (RhsT->isVoidType())
4886  return LhsT->isVoidType();
4887 
4888  // A function definition requires a complete, non-abstract return type.
4889  if (!Self.isCompleteType(KeyLoc, RhsT) || Self.isAbstractType(KeyLoc, RhsT))
4890  return false;
4891 
4892  // Compute the result of add_rvalue_reference.
4893  if (LhsT->isObjectType() || LhsT->isFunctionType())
4894  LhsT = Self.Context.getRValueReferenceType(LhsT);
4895 
4896  // Build a fake source and destination for initialization.
4898  OpaqueValueExpr From(KeyLoc, LhsT.getNonLValueExprType(Self.Context),
4900  Expr *FromPtr = &From;
4902  SourceLocation()));
4903 
4904  // Perform the initialization in an unevaluated context within a SFINAE
4905  // trap at translation unit scope.
4908  Sema::SFINAETrap SFINAE(Self, /*AccessCheckingSFINAE=*/true);
4909  Sema::ContextRAII TUContext(Self, Self.Context.getTranslationUnitDecl());
4910  InitializationSequence Init(Self, To, Kind, FromPtr);
4911  if (Init.Failed())
4912  return false;
4913 
4914  ExprResult Result = Init.Perform(Self, To, Kind, FromPtr);
4915  return !Result.isInvalid() && !SFINAE.hasErrorOccurred();
4916  }
4917 
4918  case BTT_IsAssignable:
4921  // C++11 [meta.unary.prop]p3:
4922  // is_trivially_assignable is defined as:
4923  // is_assignable<T, U>::value is true and the assignment, as defined by
4924  // is_assignable, is known to call no operation that is not trivial
4925  //
4926  // is_assignable is defined as:
4927  // The expression declval<T>() = declval<U>() is well-formed when
4928  // treated as an unevaluated operand (Clause 5).
4929  //
4930  // For both, T and U shall be complete types, (possibly cv-qualified)
4931  // void, or arrays of unknown bound.
4932  if (!LhsT->isVoidType() && !LhsT->isIncompleteArrayType() &&
4933  Self.RequireCompleteType(KeyLoc, LhsT,
4934  diag::err_incomplete_type_used_in_type_trait_expr))
4935  return false;
4936  if (!RhsT->isVoidType() && !RhsT->isIncompleteArrayType() &&
4937  Self.RequireCompleteType(KeyLoc, RhsT,
4938  diag::err_incomplete_type_used_in_type_trait_expr))
4939  return false;
4940 
4941  // cv void is never assignable.
4942  if (LhsT->isVoidType() || RhsT->isVoidType())
4943  return false;
4944 
4945  // Build expressions that emulate the effect of declval<T>() and
4946  // declval<U>().
4947  if (LhsT->isObjectType() || LhsT->isFunctionType())
4948  LhsT = Self.Context.getRValueReferenceType(LhsT);
4949  if (RhsT->isObjectType() || RhsT->isFunctionType())
4950  RhsT = Self.Context.getRValueReferenceType(RhsT);
4951  OpaqueValueExpr Lhs(KeyLoc, LhsT.getNonLValueExprType(Self.Context),
4953  OpaqueValueExpr Rhs(KeyLoc, RhsT.getNonLValueExprType(Self.Context),
4955 
4956  // Attempt the assignment in an unevaluated context within a SFINAE
4957  // trap at translation unit scope.
4960  Sema::SFINAETrap SFINAE(Self, /*AccessCheckingSFINAE=*/true);
4961  Sema::ContextRAII TUContext(Self, Self.Context.getTranslationUnitDecl());
4962  ExprResult Result = Self.BuildBinOp(/*S=*/nullptr, KeyLoc, BO_Assign, &Lhs,
4963  &Rhs);
4964  if (Result.isInvalid() || SFINAE.hasErrorOccurred())
4965  return false;
4966 
4967  if (BTT == BTT_IsAssignable)
4968  return true;
4969 
4970  if (BTT == BTT_IsNothrowAssignable)
4971  return Self.canThrow(Result.get()) == CT_Cannot;
4972 
4973  if (BTT == BTT_IsTriviallyAssignable) {
4974  // Under Objective-C ARC and Weak, if the destination has non-trivial
4975  // Objective-C lifetime, this is a non-trivial assignment.
4977  return false;
4978 
4979  return !Result.get()->hasNonTrivialCall(Self.Context);
4980  }
4981 
4982  llvm_unreachable("unhandled type trait");
4983  return false;
4984  }
4985  default: llvm_unreachable("not a BTT");
4986  }
4987  llvm_unreachable("Unknown type trait or not implemented");
4988 }
4989 
4991  SourceLocation KWLoc,
4992  ParsedType Ty,
4993  Expr* DimExpr,
4994  SourceLocation RParen) {
4995  TypeSourceInfo *TSInfo;
4996  QualType T = GetTypeFromParser(Ty, &TSInfo);
4997  if (!TSInfo)
4998  TSInfo = Context.getTrivialTypeSourceInfo(T);
4999 
5000  return BuildArrayTypeTrait(ATT, KWLoc, TSInfo, DimExpr, RParen);
5001 }
5002 
5003 static uint64_t EvaluateArrayTypeTrait(Sema &Self, ArrayTypeTrait ATT,
5004  QualType T, Expr *DimExpr,
5005  SourceLocation KeyLoc) {
5006  assert(!T->isDependentType() && "Cannot evaluate traits of dependent type");
5007 
5008  switch(ATT) {
5009  case ATT_ArrayRank:
5010  if (T->isArrayType()) {
5011  unsigned Dim = 0;
5012  while (const ArrayType *AT = Self.Context.getAsArrayType(T)) {
5013  ++Dim;
5014  T = AT->getElementType();
5015  }
5016  return Dim;
5017  }
5018  return 0;
5019 
5020  case ATT_ArrayExtent: {
5021  llvm::APSInt Value;
5022  uint64_t Dim;
5023  if (Self.VerifyIntegerConstantExpression(DimExpr, &Value,
5024  diag::err_dimension_expr_not_constant_integer,
5025  false).isInvalid())
5026  return 0;
5027  if (Value.isSigned() && Value.isNegative()) {
5028  Self.Diag(KeyLoc, diag::err_dimension_expr_not_constant_integer)
5029  << DimExpr->getSourceRange();
5030  return 0;
5031  }
5032  Dim = Value.getLimitedValue();
5033 
5034  if (T->isArrayType()) {
5035  unsigned D = 0;
5036  bool Matched = false;
5037  while (const ArrayType *AT = Self.Context.getAsArrayType(T)) {
5038  if (Dim == D) {
5039  Matched = true;
5040  break;
5041  }
5042  ++D;
5043  T = AT->getElementType();
5044  }
5045 
5046  if (Matched && T->isArrayType()) {
5047  if (const ConstantArrayType *CAT = Self.Context.getAsConstantArrayType(T))
5048  return CAT->getSize().getLimitedValue();
5049  }
5050  }
5051  return 0;
5052  }
5053  }
5054  llvm_unreachable("Unknown type trait or not implemented");
5055 }
5056 
5058  SourceLocation KWLoc,
5059  TypeSourceInfo *TSInfo,
5060  Expr* DimExpr,
5061  SourceLocation RParen) {
5062  QualType T = TSInfo->getType();
5063 
5064  // FIXME: This should likely be tracked as an APInt to remove any host
5065  // assumptions about the width of size_t on the target.
5066  uint64_t Value = 0;
5067  if (!T->isDependentType())
5068  Value = EvaluateArrayTypeTrait(*this, ATT, T, DimExpr, KWLoc);
5069 
5070  // While the specification for these traits from the Embarcadero C++
5071  // compiler's documentation says the return type is 'unsigned int', Clang
5072  // returns 'size_t'. On Windows, the primary platform for the Embarcadero
5073  // compiler, there is no difference. On several other platforms this is an
5074  // important distinction.
5075  return new (Context) ArrayTypeTraitExpr(KWLoc, ATT, TSInfo, Value, DimExpr,
5076  RParen, Context.getSizeType());
5077 }
5078 
5080  SourceLocation KWLoc,
5081  Expr *Queried,
5082  SourceLocation RParen) {
5083  // If error parsing the expression, ignore.
5084  if (!Queried)
5085  return ExprError();
5086 
5087  ExprResult Result = BuildExpressionTrait(ET, KWLoc, Queried, RParen);
5088 
5089  return Result;
5090 }
5091 
5093  switch (ET) {
5094  case ET_IsLValueExpr: return E->isLValue();
5095  case ET_IsRValueExpr: return E->isRValue();
5096  }
5097  llvm_unreachable("Expression trait not covered by switch");
5098 }
5099 
5101  SourceLocation KWLoc,
5102  Expr *Queried,
5103  SourceLocation RParen) {
5104  if (Queried->isTypeDependent()) {
5105  // Delay type-checking for type-dependent expressions.
5106  } else if (Queried->getType()->isPlaceholderType()) {
5107  ExprResult PE = CheckPlaceholderExpr(Queried);
5108  if (PE.isInvalid()) return ExprError();
5109  return BuildExpressionTrait(ET, KWLoc, PE.get(), RParen);
5110  }
5111 
5112  bool Value = EvaluateExpressionTrait(ET, Queried);
5113 
5114  return new (Context)
5115  ExpressionTraitExpr(KWLoc, ET, Queried, Value, RParen, Context.BoolTy);
5116 }
5117 
5119  ExprValueKind &VK,
5120  SourceLocation Loc,
5121  bool isIndirect) {
5122  assert(!LHS.get()->getType()->isPlaceholderType() &&
5123  !RHS.get()->getType()->isPlaceholderType() &&
5124  "placeholders should have been weeded out by now");
5125 
5126  // The LHS undergoes lvalue conversions if this is ->*, and undergoes the
5127  // temporary materialization conversion otherwise.
5128  if (isIndirect)
5129  LHS = DefaultLvalueConversion(LHS.get());
5130  else if (LHS.get()->isRValue())
5132  if (LHS.isInvalid())
5133  return QualType();
5134 
5135  // The RHS always undergoes lvalue conversions.
5136  RHS = DefaultLvalueConversion(RHS.get());
5137  if (RHS.isInvalid()) return QualType();
5138 
5139  const char *OpSpelling = isIndirect ? "->*" : ".*";
5140  // C++ 5.5p2
5141  // The binary operator .* [p3: ->*] binds its second operand, which shall
5142  // be of type "pointer to member of T" (where T is a completely-defined
5143  // class type) [...]
5144  QualType RHSType = RHS.get()->getType();
5145  const MemberPointerType *MemPtr = RHSType->getAs<MemberPointerType>();
5146  if (!MemPtr) {
5147  Diag(Loc, diag::err_bad_memptr_rhs)
5148  << OpSpelling << RHSType << RHS.get()->getSourceRange();
5149  return QualType();
5150  }
5151 
5152  QualType Class(MemPtr->getClass(), 0);
5153 
5154  // Note: C++ [expr.mptr.oper]p2-3 says that the class type into which the
5155  // member pointer points must be completely-defined. However, there is no
5156  // reason for this semantic distinction, and the rule is not enforced by
5157  // other compilers. Therefore, we do not check this property, as it is
5158  // likely to be considered a defect.
5159 
5160  // C++ 5.5p2
5161  // [...] to its first operand, which shall be of class T or of a class of
5162  // which T is an unambiguous and accessible base class. [p3: a pointer to
5163  // such a class]
5164  QualType LHSType = LHS.get()->getType();
5165  if (isIndirect) {
5166  if (const PointerType *Ptr = LHSType->getAs<PointerType>())
5167  LHSType = Ptr->getPointeeType();
5168  else {
5169  Diag(Loc, diag::err_bad_memptr_lhs)
5170  << OpSpelling << 1 << LHSType
5172  return QualType();
5173  }
5174  }
5175 
5176  if (!Context.hasSameUnqualifiedType(Class, LHSType)) {
5177  // If we want to check the hierarchy, we need a complete type.
5178  if (RequireCompleteType(Loc, LHSType, diag::err_bad_memptr_lhs,
5179  OpSpelling, (int)isIndirect)) {
5180  return QualType();
5181  }
5182 
5183  if (!IsDerivedFrom(Loc, LHSType, Class)) {
5184  Diag(Loc, diag::err_bad_memptr_lhs) << OpSpelling
5185  << (int)isIndirect << LHS.get()->getType();
5186  return QualType();
5187  }
5188 
5189  CXXCastPath BasePath;
5190  if (CheckDerivedToBaseConversion(LHSType, Class, Loc,
5191  SourceRange(LHS.get()->getLocStart(),
5192  RHS.get()->getLocEnd()),
5193  &BasePath))
5194  return QualType();
5195 
5196  // Cast LHS to type of use.
5197  QualType UseType = Context.getQualifiedType(Class, LHSType.getQualifiers());
5198  if (isIndirect)
5199  UseType = Context.getPointerType(UseType);
5200  ExprValueKind VK = isIndirect ? VK_RValue : LHS.get()->getValueKind();
5201  LHS = ImpCastExprToType(LHS.get(), UseType, CK_DerivedToBase, VK,
5202  &BasePath);
5203  }
5204 
5205  if (isa<CXXScalarValueInitExpr>(RHS.get()->IgnoreParens())) {
5206  // Diagnose use of pointer-to-member type which when used as
5207  // the functional cast in a pointer-to-member expression.
5208  Diag(Loc, diag::err_pointer_to_member_type) << isIndirect;
5209  return QualType();
5210  }
5211 
5212  // C++ 5.5p2
5213  // The result is an object or a function of the type specified by the
5214  // second operand.
5215  // The cv qualifiers are the union of those in the pointer and the left side,
5216  // in accordance with 5.5p5 and 5.2.5.
5217  QualType Result = MemPtr->getPointeeType();
5218  Result = Context.getCVRQualifiedType(Result, LHSType.getCVRQualifiers());
5219 
5220  // C++0x [expr.mptr.oper]p6:
5221  // In a .* expression whose object expression is an rvalue, the program is
5222  // ill-formed if the second operand is a pointer to member function with
5223  // ref-qualifier &. In a ->* expression or in a .* expression whose object
5224  // expression is an lvalue, the program is ill-formed if the second operand
5225  // is a pointer to member function with ref-qualifier &&.
5226  if (const FunctionProtoType *Proto = Result->getAs<FunctionProtoType>()) {
5227  switch (Proto->getRefQualifier()) {
5228  case RQ_None:
5229  // Do nothing
5230  break;
5231 
5232  case RQ_LValue:
5233  if (!isIndirect && !LHS.get()->Classify(Context).isLValue()) {
5234  // C++2a allows functions with ref-qualifier & if they are also 'const'.
5235  if (Proto->isConst())
5236  Diag(Loc, getLangOpts().CPlusPlus2a
5237  ? diag::warn_cxx17_compat_pointer_to_const_ref_member_on_rvalue
5238  : diag::ext_pointer_to_const_ref_member_on_rvalue);
5239  else
5240  Diag(Loc, diag::err_pointer_to_member_oper_value_classify)
5241  << RHSType << 1 << LHS.get()->getSourceRange();
5242  }
5243  break;
5244 
5245  case RQ_RValue:
5246  if (isIndirect || !LHS.get()->Classify(Context).isRValue())
5247  Diag(Loc, diag::err_pointer_to_member_oper_value_classify)
5248  << RHSType << 0 << LHS.get()->getSourceRange();
5249  break;
5250  }
5251  }
5252 
5253  // C++ [expr.mptr.oper]p6:
5254  // The result of a .* expression whose second operand is a pointer
5255  // to a data member is of the same value category as its
5256  // first operand. The result of a .* expression whose second
5257  // operand is a pointer to a member function is a prvalue. The
5258  // result of an ->* expression is an lvalue if its second operand
5259  // is a pointer to data member and a prvalue otherwise.
5260  if (Result->isFunctionType()) {
5261  VK = VK_RValue;
5262  return Context.BoundMemberTy;
5263  } else if (isIndirect) {
5264  VK = VK_LValue;
5265  } else {
5266  VK = LHS.get()->getValueKind();
5267  }
5268 
5269  return Result;
5270 }
5271 
5272 /// \brief Try to convert a type to another according to C++11 5.16p3.
5273 ///
5274 /// This is part of the parameter validation for the ? operator. If either
5275 /// value operand is a class type, the two operands are attempted to be
5276 /// converted to each other. This function does the conversion in one direction.
5277 /// It returns true if the program is ill-formed and has already been diagnosed
5278 /// as such.
5279 static bool TryClassUnification(Sema &Self, Expr *From, Expr *To,
5280  SourceLocation QuestionLoc,
5281  bool &HaveConversion,
5282  QualType &ToType) {
5283  HaveConversion = false;
5284  ToType = To->getType();
5285 
5287  SourceLocation());
5288  // C++11 5.16p3
5289  // The process for determining whether an operand expression E1 of type T1
5290  // can be converted to match an operand expression E2 of type T2 is defined
5291  // as follows:
5292  // -- If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
5293  // implicitly converted to type "lvalue reference to T2", subject to the
5294  // constraint that in the conversion the reference must bind directly to
5295  // an lvalue.
5296  // -- If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
5297  // implicitly conveted to the type "rvalue reference to R2", subject to
5298  // the constraint that the reference must bind directly.
5299  if (To->isLValue() || To->isXValue()) {
5300  QualType T = To->isLValue() ? Self.Context.getLValueReferenceType(ToType)
5301  : Self.Context.getRValueReferenceType(ToType);
5302 
5304 
5305  InitializationSequence InitSeq(Self, Entity, Kind, From);
5306  if (InitSeq.isDirectReferenceBinding()) {
5307  ToType = T;
5308  HaveConversion = true;
5309  return false;
5310  }
5311 
5312  if (InitSeq.isAmbiguous())
5313  return InitSeq.Diagnose(Self, Entity, Kind, From);
5314  }
5315 
5316  // -- If E2 is an rvalue, or if the conversion above cannot be done:
5317  // -- if E1 and E2 have class type, and the underlying class types are
5318  // the same or one is a base class of the other:
5319  QualType FTy = From->getType();
5320  QualType TTy = To->getType();
5321  const RecordType *FRec = FTy->getAs<RecordType>();
5322  const RecordType *TRec = TTy->getAs<RecordType>();
5323  bool FDerivedFromT = FRec && TRec && FRec != TRec &&
5324  Self.IsDerivedFrom(QuestionLoc, FTy, TTy);
5325  if (FRec && TRec && (FRec == TRec || FDerivedFromT ||
5326  Self.IsDerivedFrom(QuestionLoc, TTy, FTy))) {
5327  // E1 can be converted to match E2 if the class of T2 is the
5328  // same type as, or a base class of, the class of T1, and
5329  // [cv2 > cv1].
5330  if (FRec == TRec || FDerivedFromT) {
5331  if (TTy.isAtLeastAsQualifiedAs(FTy)) {
5333  InitializationSequence InitSeq(Self, Entity, Kind, From);
5334  if (InitSeq) {
5335  HaveConversion = true;
5336  return false;
5337  }
5338 
5339  if (InitSeq.isAmbiguous())
5340  return InitSeq.Diagnose(Self, Entity, Kind, From);
5341  }
5342  }
5343 
5344  return false;
5345  }
5346 
5347  // -- Otherwise: E1 can be converted to match E2 if E1 can be
5348  // implicitly converted to the type that expression E2 would have
5349  // if E2 were converted to an rvalue (or the type it has, if E2 is
5350  // an rvalue).
5351  //
5352  // This actually refers very narrowly to the lvalue-to-rvalue conversion, not
5353  // to the array-to-pointer or function-to-pointer conversions.
5354  TTy = TTy.getNonLValueExprType(Self.