clang  6.0.0svn
SemaDecl.cpp
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1 //===--- SemaDecl.cpp - Semantic Analysis for Declarations ----------------===//
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 // This file implements semantic analysis for declarations.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "TypeLocBuilder.h"
15 #include "clang/AST/ASTConsumer.h"
16 #include "clang/AST/ASTContext.h"
17 #include "clang/AST/ASTLambda.h"
19 #include "clang/AST/CharUnits.h"
21 #include "clang/AST/DeclCXX.h"
22 #include "clang/AST/DeclObjC.h"
23 #include "clang/AST/DeclTemplate.h"
25 #include "clang/AST/ExprCXX.h"
26 #include "clang/AST/StmtCXX.h"
27 #include "clang/Basic/Builtins.h"
30 #include "clang/Basic/TargetInfo.h"
31 #include "clang/Lex/HeaderSearch.h" // TODO: Sema shouldn't depend on Lex
32 #include "clang/Lex/Lexer.h" // TODO: Extract static functions to fix layering.
33 #include "clang/Lex/ModuleLoader.h" // TODO: Sema shouldn't depend on Lex
34 #include "clang/Lex/Preprocessor.h" // Included for isCodeCompletionEnabled()
36 #include "clang/Sema/DeclSpec.h"
39 #include "clang/Sema/Lookup.h"
41 #include "clang/Sema/Scope.h"
42 #include "clang/Sema/ScopeInfo.h"
44 #include "clang/Sema/Template.h"
45 #include "llvm/ADT/SmallString.h"
46 #include "llvm/ADT/Triple.h"
47 #include <algorithm>
48 #include <cstring>
49 #include <functional>
50 
51 using namespace clang;
52 using namespace sema;
53 
55  if (OwnedType) {
56  Decl *Group[2] = { OwnedType, Ptr };
57  return DeclGroupPtrTy::make(DeclGroupRef::Create(Context, Group, 2));
58  }
59 
60  return DeclGroupPtrTy::make(DeclGroupRef(Ptr));
61 }
62 
63 namespace {
64 
65 class TypeNameValidatorCCC : public CorrectionCandidateCallback {
66  public:
67  TypeNameValidatorCCC(bool AllowInvalid, bool WantClass = false,
68  bool AllowTemplates = false,
69  bool AllowNonTemplates = true)
70  : AllowInvalidDecl(AllowInvalid), WantClassName(WantClass),
71  AllowTemplates(AllowTemplates), AllowNonTemplates(AllowNonTemplates) {
72  WantExpressionKeywords = false;
73  WantCXXNamedCasts = false;
74  WantRemainingKeywords = false;
75  }
76 
77  bool ValidateCandidate(const TypoCorrection &candidate) override {
78  if (NamedDecl *ND = candidate.getCorrectionDecl()) {
79  if (!AllowInvalidDecl && ND->isInvalidDecl())
80  return false;
81 
82  if (getAsTypeTemplateDecl(ND))
83  return AllowTemplates;
84 
85  bool IsType = isa<TypeDecl>(ND) || isa<ObjCInterfaceDecl>(ND);
86  if (!IsType)
87  return false;
88 
89  if (AllowNonTemplates)
90  return true;
91 
92  // An injected-class-name of a class template (specialization) is valid
93  // as a template or as a non-template.
94  if (AllowTemplates) {
95  auto *RD = dyn_cast<CXXRecordDecl>(ND);
96  if (!RD || !RD->isInjectedClassName())
97  return false;
98  RD = cast<CXXRecordDecl>(RD->getDeclContext());
99  return RD->getDescribedClassTemplate() ||
100  isa<ClassTemplateSpecializationDecl>(RD);
101  }
102 
103  return false;
104  }
105 
106  return !WantClassName && candidate.isKeyword();
107  }
108 
109  private:
110  bool AllowInvalidDecl;
111  bool WantClassName;
112  bool AllowTemplates;
113  bool AllowNonTemplates;
114 };
115 
116 } // end anonymous namespace
117 
118 /// \brief Determine whether the token kind starts a simple-type-specifier.
120  switch (Kind) {
121  // FIXME: Take into account the current language when deciding whether a
122  // token kind is a valid type specifier
123  case tok::kw_short:
124  case tok::kw_long:
125  case tok::kw___int64:
126  case tok::kw___int128:
127  case tok::kw_signed:
128  case tok::kw_unsigned:
129  case tok::kw_void:
130  case tok::kw_char:
131  case tok::kw_int:
132  case tok::kw_half:
133  case tok::kw_float:
134  case tok::kw_double:
135  case tok::kw__Float16:
136  case tok::kw___float128:
137  case tok::kw_wchar_t:
138  case tok::kw_bool:
139  case tok::kw___underlying_type:
140  case tok::kw___auto_type:
141  return true;
142 
143  case tok::annot_typename:
144  case tok::kw_char16_t:
145  case tok::kw_char32_t:
146  case tok::kw_typeof:
147  case tok::annot_decltype:
148  case tok::kw_decltype:
149  return getLangOpts().CPlusPlus;
150 
151  default:
152  break;
153  }
154 
155  return false;
156 }
157 
158 namespace {
160  NotFound,
161  FoundNonType,
162  FoundType
163 };
164 } // end anonymous namespace
165 
166 /// \brief Tries to perform unqualified lookup of the type decls in bases for
167 /// dependent class.
168 /// \return \a NotFound if no any decls is found, \a FoundNotType if found not a
169 /// type decl, \a FoundType if only type decls are found.
172  SourceLocation NameLoc,
173  const CXXRecordDecl *RD) {
174  if (!RD->hasDefinition())
175  return UnqualifiedTypeNameLookupResult::NotFound;
176  // Look for type decls in base classes.
177  UnqualifiedTypeNameLookupResult FoundTypeDecl =
178  UnqualifiedTypeNameLookupResult::NotFound;
179  for (const auto &Base : RD->bases()) {
180  const CXXRecordDecl *BaseRD = nullptr;
181  if (auto *BaseTT = Base.getType()->getAs<TagType>())
182  BaseRD = BaseTT->getAsCXXRecordDecl();
183  else if (auto *TST = Base.getType()->getAs<TemplateSpecializationType>()) {
184  // Look for type decls in dependent base classes that have known primary
185  // templates.
186  if (!TST || !TST->isDependentType())
187  continue;
188  auto *TD = TST->getTemplateName().getAsTemplateDecl();
189  if (!TD)
190  continue;
191  if (auto *BasePrimaryTemplate =
192  dyn_cast_or_null<CXXRecordDecl>(TD->getTemplatedDecl())) {
193  if (BasePrimaryTemplate->getCanonicalDecl() != RD->getCanonicalDecl())
194  BaseRD = BasePrimaryTemplate;
195  else if (auto *CTD = dyn_cast<ClassTemplateDecl>(TD)) {
197  CTD->findPartialSpecialization(Base.getType()))
198  if (PS->getCanonicalDecl() != RD->getCanonicalDecl())
199  BaseRD = PS;
200  }
201  }
202  }
203  if (BaseRD) {
204  for (NamedDecl *ND : BaseRD->lookup(&II)) {
205  if (!isa<TypeDecl>(ND))
206  return UnqualifiedTypeNameLookupResult::FoundNonType;
207  FoundTypeDecl = UnqualifiedTypeNameLookupResult::FoundType;
208  }
209  if (FoundTypeDecl == UnqualifiedTypeNameLookupResult::NotFound) {
210  switch (lookupUnqualifiedTypeNameInBase(S, II, NameLoc, BaseRD)) {
211  case UnqualifiedTypeNameLookupResult::FoundNonType:
212  return UnqualifiedTypeNameLookupResult::FoundNonType;
213  case UnqualifiedTypeNameLookupResult::FoundType:
214  FoundTypeDecl = UnqualifiedTypeNameLookupResult::FoundType;
215  break;
216  case UnqualifiedTypeNameLookupResult::NotFound:
217  break;
218  }
219  }
220  }
221  }
222 
223  return FoundTypeDecl;
224 }
225 
227  const IdentifierInfo &II,
228  SourceLocation NameLoc) {
229  // Lookup in the parent class template context, if any.
230  const CXXRecordDecl *RD = nullptr;
231  UnqualifiedTypeNameLookupResult FoundTypeDecl =
232  UnqualifiedTypeNameLookupResult::NotFound;
233  for (DeclContext *DC = S.CurContext;
234  DC && FoundTypeDecl == UnqualifiedTypeNameLookupResult::NotFound;
235  DC = DC->getParent()) {
236  // Look for type decls in dependent base classes that have known primary
237  // templates.
238  RD = dyn_cast<CXXRecordDecl>(DC);
239  if (RD && RD->getDescribedClassTemplate())
240  FoundTypeDecl = lookupUnqualifiedTypeNameInBase(S, II, NameLoc, RD);
241  }
242  if (FoundTypeDecl != UnqualifiedTypeNameLookupResult::FoundType)
243  return nullptr;
244 
245  // We found some types in dependent base classes. Recover as if the user
246  // wrote 'typename MyClass::II' instead of 'II'. We'll fully resolve the
247  // lookup during template instantiation.
248  S.Diag(NameLoc, diag::ext_found_via_dependent_bases_lookup) << &II;
249 
250  ASTContext &Context = S.Context;
251  auto *NNS = NestedNameSpecifier::Create(Context, nullptr, false,
252  cast<Type>(Context.getRecordType(RD)));
253  QualType T = Context.getDependentNameType(ETK_Typename, NNS, &II);
254 
255  CXXScopeSpec SS;
256  SS.MakeTrivial(Context, NNS, SourceRange(NameLoc));
257 
258  TypeLocBuilder Builder;
260  DepTL.setNameLoc(NameLoc);
262  DepTL.setQualifierLoc(SS.getWithLocInContext(Context));
263  return S.CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
264 }
265 
266 /// \brief If the identifier refers to a type name within this scope,
267 /// return the declaration of that type.
268 ///
269 /// This routine performs ordinary name lookup of the identifier II
270 /// within the given scope, with optional C++ scope specifier SS, to
271 /// determine whether the name refers to a type. If so, returns an
272 /// opaque pointer (actually a QualType) corresponding to that
273 /// type. Otherwise, returns NULL.
275  Scope *S, CXXScopeSpec *SS,
276  bool isClassName, bool HasTrailingDot,
277  ParsedType ObjectTypePtr,
278  bool IsCtorOrDtorName,
279  bool WantNontrivialTypeSourceInfo,
280  bool IsClassTemplateDeductionContext,
281  IdentifierInfo **CorrectedII) {
282  // FIXME: Consider allowing this outside C++1z mode as an extension.
283  bool AllowDeducedTemplate = IsClassTemplateDeductionContext &&
284  getLangOpts().CPlusPlus1z && !IsCtorOrDtorName &&
285  !isClassName && !HasTrailingDot;
286 
287  // Determine where we will perform name lookup.
288  DeclContext *LookupCtx = nullptr;
289  if (ObjectTypePtr) {
290  QualType ObjectType = ObjectTypePtr.get();
291  if (ObjectType->isRecordType())
292  LookupCtx = computeDeclContext(ObjectType);
293  } else if (SS && SS->isNotEmpty()) {
294  LookupCtx = computeDeclContext(*SS, false);
295 
296  if (!LookupCtx) {
297  if (isDependentScopeSpecifier(*SS)) {
298  // C++ [temp.res]p3:
299  // A qualified-id that refers to a type and in which the
300  // nested-name-specifier depends on a template-parameter (14.6.2)
301  // shall be prefixed by the keyword typename to indicate that the
302  // qualified-id denotes a type, forming an
303  // elaborated-type-specifier (7.1.5.3).
304  //
305  // We therefore do not perform any name lookup if the result would
306  // refer to a member of an unknown specialization.
307  if (!isClassName && !IsCtorOrDtorName)
308  return nullptr;
309 
310  // We know from the grammar that this name refers to a type,
311  // so build a dependent node to describe the type.
312  if (WantNontrivialTypeSourceInfo)
313  return ActOnTypenameType(S, SourceLocation(), *SS, II, NameLoc).get();
314 
315  NestedNameSpecifierLoc QualifierLoc = SS->getWithLocInContext(Context);
316  QualType T = CheckTypenameType(ETK_None, SourceLocation(), QualifierLoc,
317  II, NameLoc);
318  return ParsedType::make(T);
319  }
320 
321  return nullptr;
322  }
323 
324  if (!LookupCtx->isDependentContext() &&
325  RequireCompleteDeclContext(*SS, LookupCtx))
326  return nullptr;
327  }
328 
329  // FIXME: LookupNestedNameSpecifierName isn't the right kind of
330  // lookup for class-names.
331  LookupNameKind Kind = isClassName ? LookupNestedNameSpecifierName :
332  LookupOrdinaryName;
333  LookupResult Result(*this, &II, NameLoc, Kind);
334  if (LookupCtx) {
335  // Perform "qualified" name lookup into the declaration context we
336  // computed, which is either the type of the base of a member access
337  // expression or the declaration context associated with a prior
338  // nested-name-specifier.
339  LookupQualifiedName(Result, LookupCtx);
340 
341  if (ObjectTypePtr && Result.empty()) {
342  // C++ [basic.lookup.classref]p3:
343  // If the unqualified-id is ~type-name, the type-name is looked up
344  // in the context of the entire postfix-expression. If the type T of
345  // the object expression is of a class type C, the type-name is also
346  // looked up in the scope of class C. At least one of the lookups shall
347  // find a name that refers to (possibly cv-qualified) T.
348  LookupName(Result, S);
349  }
350  } else {
351  // Perform unqualified name lookup.
352  LookupName(Result, S);
353 
354  // For unqualified lookup in a class template in MSVC mode, look into
355  // dependent base classes where the primary class template is known.
356  if (Result.empty() && getLangOpts().MSVCCompat && (!SS || SS->isEmpty())) {
357  if (ParsedType TypeInBase =
358  recoverFromTypeInKnownDependentBase(*this, II, NameLoc))
359  return TypeInBase;
360  }
361  }
362 
363  NamedDecl *IIDecl = nullptr;
364  switch (Result.getResultKind()) {
367  if (CorrectedII) {
368  TypoCorrection Correction =
369  CorrectTypo(Result.getLookupNameInfo(), Kind, S, SS,
370  llvm::make_unique<TypeNameValidatorCCC>(
371  true, isClassName, AllowDeducedTemplate),
372  CTK_ErrorRecovery);
373  IdentifierInfo *NewII = Correction.getCorrectionAsIdentifierInfo();
374  TemplateTy Template;
375  bool MemberOfUnknownSpecialization;
377  TemplateName.setIdentifier(NewII, NameLoc);
378  NestedNameSpecifier *NNS = Correction.getCorrectionSpecifier();
379  CXXScopeSpec NewSS, *NewSSPtr = SS;
380  if (SS && NNS) {
381  NewSS.MakeTrivial(Context, NNS, SourceRange(NameLoc));
382  NewSSPtr = &NewSS;
383  }
384  if (Correction && (NNS || NewII != &II) &&
385  // Ignore a correction to a template type as the to-be-corrected
386  // identifier is not a template (typo correction for template names
387  // is handled elsewhere).
388  !(getLangOpts().CPlusPlus && NewSSPtr &&
389  isTemplateName(S, *NewSSPtr, false, TemplateName, nullptr, false,
390  Template, MemberOfUnknownSpecialization))) {
391  ParsedType Ty = getTypeName(*NewII, NameLoc, S, NewSSPtr,
392  isClassName, HasTrailingDot, ObjectTypePtr,
393  IsCtorOrDtorName,
394  WantNontrivialTypeSourceInfo,
395  IsClassTemplateDeductionContext);
396  if (Ty) {
397  diagnoseTypo(Correction,
398  PDiag(diag::err_unknown_type_or_class_name_suggest)
399  << Result.getLookupName() << isClassName);
400  if (SS && NNS)
401  SS->MakeTrivial(Context, NNS, SourceRange(NameLoc));
402  *CorrectedII = NewII;
403  return Ty;
404  }
405  }
406  }
407  // If typo correction failed or was not performed, fall through
408  LLVM_FALLTHROUGH;
411  Result.suppressDiagnostics();
412  return nullptr;
413 
415  // Recover from type-hiding ambiguities by hiding the type. We'll
416  // do the lookup again when looking for an object, and we can
417  // diagnose the error then. If we don't do this, then the error
418  // about hiding the type will be immediately followed by an error
419  // that only makes sense if the identifier was treated like a type.
421  Result.suppressDiagnostics();
422  return nullptr;
423  }
424 
425  // Look to see if we have a type anywhere in the list of results.
426  for (LookupResult::iterator Res = Result.begin(), ResEnd = Result.end();
427  Res != ResEnd; ++Res) {
428  if (isa<TypeDecl>(*Res) || isa<ObjCInterfaceDecl>(*Res) ||
429  (AllowDeducedTemplate && getAsTypeTemplateDecl(*Res))) {
430  if (!IIDecl ||
431  (*Res)->getLocation().getRawEncoding() <
432  IIDecl->getLocation().getRawEncoding())
433  IIDecl = *Res;
434  }
435  }
436 
437  if (!IIDecl) {
438  // None of the entities we found is a type, so there is no way
439  // to even assume that the result is a type. In this case, don't
440  // complain about the ambiguity. The parser will either try to
441  // perform this lookup again (e.g., as an object name), which
442  // will produce the ambiguity, or will complain that it expected
443  // a type name.
444  Result.suppressDiagnostics();
445  return nullptr;
446  }
447 
448  // We found a type within the ambiguous lookup; diagnose the
449  // ambiguity and then return that type. This might be the right
450  // answer, or it might not be, but it suppresses any attempt to
451  // perform the name lookup again.
452  break;
453 
454  case LookupResult::Found:
455  IIDecl = Result.getFoundDecl();
456  break;
457  }
458 
459  assert(IIDecl && "Didn't find decl");
460 
461  QualType T;
462  if (TypeDecl *TD = dyn_cast<TypeDecl>(IIDecl)) {
463  // C++ [class.qual]p2: A lookup that would find the injected-class-name
464  // instead names the constructors of the class, except when naming a class.
465  // This is ill-formed when we're not actually forming a ctor or dtor name.
466  auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
467  auto *FoundRD = dyn_cast<CXXRecordDecl>(TD);
468  if (!isClassName && !IsCtorOrDtorName && LookupRD && FoundRD &&
469  FoundRD->isInjectedClassName() &&
470  declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent())))
471  Diag(NameLoc, diag::err_out_of_line_qualified_id_type_names_constructor)
472  << &II << /*Type*/1;
473 
474  DiagnoseUseOfDecl(IIDecl, NameLoc);
475 
476  T = Context.getTypeDeclType(TD);
477  MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
478  } else if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(IIDecl)) {
479  (void)DiagnoseUseOfDecl(IDecl, NameLoc);
480  if (!HasTrailingDot)
481  T = Context.getObjCInterfaceType(IDecl);
482  } else if (AllowDeducedTemplate) {
483  if (auto *TD = getAsTypeTemplateDecl(IIDecl))
485  QualType(), false);
486  }
487 
488  if (T.isNull()) {
489  // If it's not plausibly a type, suppress diagnostics.
490  Result.suppressDiagnostics();
491  return nullptr;
492  }
493 
494  // NOTE: avoid constructing an ElaboratedType(Loc) if this is a
495  // constructor or destructor name (in such a case, the scope specifier
496  // will be attached to the enclosing Expr or Decl node).
497  if (SS && SS->isNotEmpty() && !IsCtorOrDtorName &&
498  !isa<ObjCInterfaceDecl>(IIDecl)) {
499  if (WantNontrivialTypeSourceInfo) {
500  // Construct a type with type-source information.
501  TypeLocBuilder Builder;
502  Builder.pushTypeSpec(T).setNameLoc(NameLoc);
503 
504  T = getElaboratedType(ETK_None, *SS, T);
505  ElaboratedTypeLoc ElabTL = Builder.push<ElaboratedTypeLoc>(T);
507  ElabTL.setQualifierLoc(SS->getWithLocInContext(Context));
508  return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
509  } else {
510  T = getElaboratedType(ETK_None, *SS, T);
511  }
512  }
513 
514  return ParsedType::make(T);
515 }
516 
517 // Builds a fake NNS for the given decl context.
518 static NestedNameSpecifier *
520  for (;; DC = DC->getLookupParent()) {
521  DC = DC->getPrimaryContext();
522  auto *ND = dyn_cast<NamespaceDecl>(DC);
523  if (ND && !ND->isInline() && !ND->isAnonymousNamespace())
524  return NestedNameSpecifier::Create(Context, nullptr, ND);
525  else if (auto *RD = dyn_cast<CXXRecordDecl>(DC))
526  return NestedNameSpecifier::Create(Context, nullptr, RD->isTemplateDecl(),
527  RD->getTypeForDecl());
528  else if (isa<TranslationUnitDecl>(DC))
529  return NestedNameSpecifier::GlobalSpecifier(Context);
530  }
531  llvm_unreachable("something isn't in TU scope?");
532 }
533 
534 /// Find the parent class with dependent bases of the innermost enclosing method
535 /// context. Do not look for enclosing CXXRecordDecls directly, or we will end
536 /// up allowing unqualified dependent type names at class-level, which MSVC
537 /// correctly rejects.
538 static const CXXRecordDecl *
540  for (; DC && DC->isDependentContext(); DC = DC->getLookupParent()) {
541  DC = DC->getPrimaryContext();
542  if (const auto *MD = dyn_cast<CXXMethodDecl>(DC))
543  if (MD->getParent()->hasAnyDependentBases())
544  return MD->getParent();
545  }
546  return nullptr;
547 }
548 
550  SourceLocation NameLoc,
551  bool IsTemplateTypeArg) {
552  assert(getLangOpts().MSVCCompat && "shouldn't be called in non-MSVC mode");
553 
554  NestedNameSpecifier *NNS = nullptr;
555  if (IsTemplateTypeArg && getCurScope()->isTemplateParamScope()) {
556  // If we weren't able to parse a default template argument, delay lookup
557  // until instantiation time by making a non-dependent DependentTypeName. We
558  // pretend we saw a NestedNameSpecifier referring to the current scope, and
559  // lookup is retried.
560  // FIXME: This hurts our diagnostic quality, since we get errors like "no
561  // type named 'Foo' in 'current_namespace'" when the user didn't write any
562  // name specifiers.
563  NNS = synthesizeCurrentNestedNameSpecifier(Context, CurContext);
564  Diag(NameLoc, diag::ext_ms_delayed_template_argument) << &II;
565  } else if (const CXXRecordDecl *RD =
567  // Build a DependentNameType that will perform lookup into RD at
568  // instantiation time.
569  NNS = NestedNameSpecifier::Create(Context, nullptr, RD->isTemplateDecl(),
570  RD->getTypeForDecl());
571 
572  // Diagnose that this identifier was undeclared, and retry the lookup during
573  // template instantiation.
574  Diag(NameLoc, diag::ext_undeclared_unqual_id_with_dependent_base) << &II
575  << RD;
576  } else {
577  // This is not a situation that we should recover from.
578  return ParsedType();
579  }
580 
581  QualType T = Context.getDependentNameType(ETK_None, NNS, &II);
582 
583  // Build type location information. We synthesized the qualifier, so we have
584  // to build a fake NestedNameSpecifierLoc.
585  NestedNameSpecifierLocBuilder NNSLocBuilder;
586  NNSLocBuilder.MakeTrivial(Context, NNS, SourceRange(NameLoc));
587  NestedNameSpecifierLoc QualifierLoc = NNSLocBuilder.getWithLocInContext(Context);
588 
589  TypeLocBuilder Builder;
591  DepTL.setNameLoc(NameLoc);
593  DepTL.setQualifierLoc(QualifierLoc);
594  return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
595 }
596 
597 /// isTagName() - This method is called *for error recovery purposes only*
598 /// to determine if the specified name is a valid tag name ("struct foo"). If
599 /// so, this returns the TST for the tag corresponding to it (TST_enum,
600 /// TST_union, TST_struct, TST_interface, TST_class). This is used to diagnose
601 /// cases in C where the user forgot to specify the tag.
603  // Do a tag name lookup in this scope.
604  LookupResult R(*this, &II, SourceLocation(), LookupTagName);
605  LookupName(R, S, false);
608  if (const TagDecl *TD = R.getAsSingle<TagDecl>()) {
609  switch (TD->getTagKind()) {
610  case TTK_Struct: return DeclSpec::TST_struct;
612  case TTK_Union: return DeclSpec::TST_union;
613  case TTK_Class: return DeclSpec::TST_class;
614  case TTK_Enum: return DeclSpec::TST_enum;
615  }
616  }
617 
619 }
620 
621 /// isMicrosoftMissingTypename - In Microsoft mode, within class scope,
622 /// if a CXXScopeSpec's type is equal to the type of one of the base classes
623 /// then downgrade the missing typename error to a warning.
624 /// This is needed for MSVC compatibility; Example:
625 /// @code
626 /// template<class T> class A {
627 /// public:
628 /// typedef int TYPE;
629 /// };
630 /// template<class T> class B : public A<T> {
631 /// public:
632 /// A<T>::TYPE a; // no typename required because A<T> is a base class.
633 /// };
634 /// @endcode
636  if (CurContext->isRecord()) {
638  return true;
639 
640  const Type *Ty = SS->getScopeRep()->getAsType();
641 
642  CXXRecordDecl *RD = cast<CXXRecordDecl>(CurContext);
643  for (const auto &Base : RD->bases())
644  if (Ty && Context.hasSameUnqualifiedType(QualType(Ty, 1), Base.getType()))
645  return true;
646  return S->isFunctionPrototypeScope();
647  }
648  return CurContext->isFunctionOrMethod() || S->isFunctionPrototypeScope();
649 }
650 
652  SourceLocation IILoc,
653  Scope *S,
654  CXXScopeSpec *SS,
655  ParsedType &SuggestedType,
656  bool IsTemplateName) {
657  // Don't report typename errors for editor placeholders.
658  if (II->isEditorPlaceholder())
659  return;
660  // We don't have anything to suggest (yet).
661  SuggestedType = nullptr;
662 
663  // There may have been a typo in the name of the type. Look up typo
664  // results, in case we have something that we can suggest.
665  if (TypoCorrection Corrected =
666  CorrectTypo(DeclarationNameInfo(II, IILoc), LookupOrdinaryName, S, SS,
667  llvm::make_unique<TypeNameValidatorCCC>(
668  false, false, IsTemplateName, !IsTemplateName),
669  CTK_ErrorRecovery)) {
670  // FIXME: Support error recovery for the template-name case.
671  bool CanRecover = !IsTemplateName;
672  if (Corrected.isKeyword()) {
673  // We corrected to a keyword.
674  diagnoseTypo(Corrected,
675  PDiag(IsTemplateName ? diag::err_no_template_suggest
676  : diag::err_unknown_typename_suggest)
677  << II);
678  II = Corrected.getCorrectionAsIdentifierInfo();
679  } else {
680  // We found a similarly-named type or interface; suggest that.
681  if (!SS || !SS->isSet()) {
682  diagnoseTypo(Corrected,
683  PDiag(IsTemplateName ? diag::err_no_template_suggest
684  : diag::err_unknown_typename_suggest)
685  << II, CanRecover);
686  } else if (DeclContext *DC = computeDeclContext(*SS, false)) {
687  std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
688  bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
689  II->getName().equals(CorrectedStr);
690  diagnoseTypo(Corrected,
691  PDiag(IsTemplateName
692  ? diag::err_no_member_template_suggest
693  : diag::err_unknown_nested_typename_suggest)
694  << II << DC << DroppedSpecifier << SS->getRange(),
695  CanRecover);
696  } else {
697  llvm_unreachable("could not have corrected a typo here");
698  }
699 
700  if (!CanRecover)
701  return;
702 
703  CXXScopeSpec tmpSS;
704  if (Corrected.getCorrectionSpecifier())
705  tmpSS.MakeTrivial(Context, Corrected.getCorrectionSpecifier(),
706  SourceRange(IILoc));
707  // FIXME: Support class template argument deduction here.
708  SuggestedType =
709  getTypeName(*Corrected.getCorrectionAsIdentifierInfo(), IILoc, S,
710  tmpSS.isSet() ? &tmpSS : SS, false, false, nullptr,
711  /*IsCtorOrDtorName=*/false,
712  /*NonTrivialTypeSourceInfo=*/true);
713  }
714  return;
715  }
716 
717  if (getLangOpts().CPlusPlus && !IsTemplateName) {
718  // See if II is a class template that the user forgot to pass arguments to.
719  UnqualifiedId Name;
720  Name.setIdentifier(II, IILoc);
721  CXXScopeSpec EmptySS;
722  TemplateTy TemplateResult;
723  bool MemberOfUnknownSpecialization;
724  if (isTemplateName(S, SS ? *SS : EmptySS, /*hasTemplateKeyword=*/false,
725  Name, nullptr, true, TemplateResult,
726  MemberOfUnknownSpecialization) == TNK_Type_template) {
727  TemplateName TplName = TemplateResult.get();
728  Diag(IILoc, diag::err_template_missing_args)
729  << (int)getTemplateNameKindForDiagnostics(TplName) << TplName;
730  if (TemplateDecl *TplDecl = TplName.getAsTemplateDecl()) {
731  Diag(TplDecl->getLocation(), diag::note_template_decl_here)
732  << TplDecl->getTemplateParameters()->getSourceRange();
733  }
734  return;
735  }
736  }
737 
738  // FIXME: Should we move the logic that tries to recover from a missing tag
739  // (struct, union, enum) from Parser::ParseImplicitInt here, instead?
740 
741  if (!SS || (!SS->isSet() && !SS->isInvalid()))
742  Diag(IILoc, IsTemplateName ? diag::err_no_template
743  : diag::err_unknown_typename)
744  << II;
745  else if (DeclContext *DC = computeDeclContext(*SS, false))
746  Diag(IILoc, IsTemplateName ? diag::err_no_member_template
747  : diag::err_typename_nested_not_found)
748  << II << DC << SS->getRange();
749  else if (isDependentScopeSpecifier(*SS)) {
750  unsigned DiagID = diag::err_typename_missing;
751  if (getLangOpts().MSVCCompat && isMicrosoftMissingTypename(SS, S))
752  DiagID = diag::ext_typename_missing;
753 
754  Diag(SS->getRange().getBegin(), DiagID)
755  << SS->getScopeRep() << II->getName()
756  << SourceRange(SS->getRange().getBegin(), IILoc)
757  << FixItHint::CreateInsertion(SS->getRange().getBegin(), "typename ");
758  SuggestedType = ActOnTypenameType(S, SourceLocation(),
759  *SS, *II, IILoc).get();
760  } else {
761  assert(SS && SS->isInvalid() &&
762  "Invalid scope specifier has already been diagnosed");
763  }
764 }
765 
766 /// \brief Determine whether the given result set contains either a type name
767 /// or
768 static bool isResultTypeOrTemplate(LookupResult &R, const Token &NextToken) {
769  bool CheckTemplate = R.getSema().getLangOpts().CPlusPlus &&
770  NextToken.is(tok::less);
771 
772  for (LookupResult::iterator I = R.begin(), IEnd = R.end(); I != IEnd; ++I) {
773  if (isa<TypeDecl>(*I) || isa<ObjCInterfaceDecl>(*I))
774  return true;
775 
776  if (CheckTemplate && isa<TemplateDecl>(*I))
777  return true;
778  }
779 
780  return false;
781 }
782 
783 static bool isTagTypeWithMissingTag(Sema &SemaRef, LookupResult &Result,
784  Scope *S, CXXScopeSpec &SS,
785  IdentifierInfo *&Name,
786  SourceLocation NameLoc) {
787  LookupResult R(SemaRef, Name, NameLoc, Sema::LookupTagName);
788  SemaRef.LookupParsedName(R, S, &SS);
789  if (TagDecl *Tag = R.getAsSingle<TagDecl>()) {
790  StringRef FixItTagName;
791  switch (Tag->getTagKind()) {
792  case TTK_Class:
793  FixItTagName = "class ";
794  break;
795 
796  case TTK_Enum:
797  FixItTagName = "enum ";
798  break;
799 
800  case TTK_Struct:
801  FixItTagName = "struct ";
802  break;
803 
804  case TTK_Interface:
805  FixItTagName = "__interface ";
806  break;
807 
808  case TTK_Union:
809  FixItTagName = "union ";
810  break;
811  }
812 
813  StringRef TagName = FixItTagName.drop_back();
814  SemaRef.Diag(NameLoc, diag::err_use_of_tag_name_without_tag)
815  << Name << TagName << SemaRef.getLangOpts().CPlusPlus
816  << FixItHint::CreateInsertion(NameLoc, FixItTagName);
817 
818  for (LookupResult::iterator I = Result.begin(), IEnd = Result.end();
819  I != IEnd; ++I)
820  SemaRef.Diag((*I)->getLocation(), diag::note_decl_hiding_tag_type)
821  << Name << TagName;
822 
823  // Replace lookup results with just the tag decl.
824  Result.clear(Sema::LookupTagName);
825  SemaRef.LookupParsedName(Result, S, &SS);
826  return true;
827  }
828 
829  return false;
830 }
831 
832 /// Build a ParsedType for a simple-type-specifier with a nested-name-specifier.
834  QualType T, SourceLocation NameLoc) {
835  ASTContext &Context = S.Context;
836 
837  TypeLocBuilder Builder;
838  Builder.pushTypeSpec(T).setNameLoc(NameLoc);
839 
840  T = S.getElaboratedType(ETK_None, SS, T);
841  ElaboratedTypeLoc ElabTL = Builder.push<ElaboratedTypeLoc>(T);
843  ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
844  return S.CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
845 }
846 
849  SourceLocation NameLoc, const Token &NextToken,
850  bool IsAddressOfOperand,
851  std::unique_ptr<CorrectionCandidateCallback> CCC) {
852  DeclarationNameInfo NameInfo(Name, NameLoc);
853  ObjCMethodDecl *CurMethod = getCurMethodDecl();
854 
855  if (NextToken.is(tok::coloncolon)) {
856  NestedNameSpecInfo IdInfo(Name, NameLoc, NextToken.getLocation());
857  BuildCXXNestedNameSpecifier(S, IdInfo, false, SS, nullptr, false);
858  } else if (getLangOpts().CPlusPlus && SS.isSet() &&
859  isCurrentClassName(*Name, S, &SS)) {
860  // Per [class.qual]p2, this names the constructors of SS, not the
861  // injected-class-name. We don't have a classification for that.
862  // There's not much point caching this result, since the parser
863  // will reject it later.
865  }
866 
867  LookupResult Result(*this, Name, NameLoc, LookupOrdinaryName);
868  LookupParsedName(Result, S, &SS, !CurMethod);
869 
870  // For unqualified lookup in a class template in MSVC mode, look into
871  // dependent base classes where the primary class template is known.
872  if (Result.empty() && SS.isEmpty() && getLangOpts().MSVCCompat) {
873  if (ParsedType TypeInBase =
874  recoverFromTypeInKnownDependentBase(*this, *Name, NameLoc))
875  return TypeInBase;
876  }
877 
878  // Perform lookup for Objective-C instance variables (including automatically
879  // synthesized instance variables), if we're in an Objective-C method.
880  // FIXME: This lookup really, really needs to be folded in to the normal
881  // unqualified lookup mechanism.
882  if (!SS.isSet() && CurMethod && !isResultTypeOrTemplate(Result, NextToken)) {
883  ExprResult E = LookupInObjCMethod(Result, S, Name, true);
884  if (E.get() || E.isInvalid())
885  return E;
886  }
887 
888  bool SecondTry = false;
889  bool IsFilteredTemplateName = false;
890 
891 Corrected:
892  switch (Result.getResultKind()) {
894  // If an unqualified-id is followed by a '(', then we have a function
895  // call.
896  if (!SS.isSet() && NextToken.is(tok::l_paren)) {
897  // In C++, this is an ADL-only call.
898  // FIXME: Reference?
899  if (getLangOpts().CPlusPlus)
900  return BuildDeclarationNameExpr(SS, Result, /*ADL=*/true);
901 
902  // C90 6.3.2.2:
903  // If the expression that precedes the parenthesized argument list in a
904  // function call consists solely of an identifier, and if no
905  // declaration is visible for this identifier, the identifier is
906  // implicitly declared exactly as if, in the innermost block containing
907  // the function call, the declaration
908  //
909  // extern int identifier ();
910  //
911  // appeared.
912  //
913  // We also allow this in C99 as an extension.
914  if (NamedDecl *D = ImplicitlyDefineFunction(NameLoc, *Name, S)) {
915  Result.addDecl(D);
916  Result.resolveKind();
917  return BuildDeclarationNameExpr(SS, Result, /*ADL=*/false);
918  }
919  }
920 
921  // In C, we first see whether there is a tag type by the same name, in
922  // which case it's likely that the user just forgot to write "enum",
923  // "struct", or "union".
924  if (!getLangOpts().CPlusPlus && !SecondTry &&
925  isTagTypeWithMissingTag(*this, Result, S, SS, Name, NameLoc)) {
926  break;
927  }
928 
929  // Perform typo correction to determine if there is another name that is
930  // close to this name.
931  if (!SecondTry && CCC) {
932  SecondTry = true;
933  if (TypoCorrection Corrected = CorrectTypo(Result.getLookupNameInfo(),
934  Result.getLookupKind(), S,
935  &SS, std::move(CCC),
936  CTK_ErrorRecovery)) {
937  unsigned UnqualifiedDiag = diag::err_undeclared_var_use_suggest;
938  unsigned QualifiedDiag = diag::err_no_member_suggest;
939 
940  NamedDecl *FirstDecl = Corrected.getFoundDecl();
941  NamedDecl *UnderlyingFirstDecl = Corrected.getCorrectionDecl();
942  if (getLangOpts().CPlusPlus && NextToken.is(tok::less) &&
943  UnderlyingFirstDecl && isa<TemplateDecl>(UnderlyingFirstDecl)) {
944  UnqualifiedDiag = diag::err_no_template_suggest;
945  QualifiedDiag = diag::err_no_member_template_suggest;
946  } else if (UnderlyingFirstDecl &&
947  (isa<TypeDecl>(UnderlyingFirstDecl) ||
948  isa<ObjCInterfaceDecl>(UnderlyingFirstDecl) ||
949  isa<ObjCCompatibleAliasDecl>(UnderlyingFirstDecl))) {
950  UnqualifiedDiag = diag::err_unknown_typename_suggest;
951  QualifiedDiag = diag::err_unknown_nested_typename_suggest;
952  }
953 
954  if (SS.isEmpty()) {
955  diagnoseTypo(Corrected, PDiag(UnqualifiedDiag) << Name);
956  } else {// FIXME: is this even reachable? Test it.
957  std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
958  bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
959  Name->getName().equals(CorrectedStr);
960  diagnoseTypo(Corrected, PDiag(QualifiedDiag)
961  << Name << computeDeclContext(SS, false)
962  << DroppedSpecifier << SS.getRange());
963  }
964 
965  // Update the name, so that the caller has the new name.
966  Name = Corrected.getCorrectionAsIdentifierInfo();
967 
968  // Typo correction corrected to a keyword.
969  if (Corrected.isKeyword())
970  return Name;
971 
972  // Also update the LookupResult...
973  // FIXME: This should probably go away at some point
974  Result.clear();
975  Result.setLookupName(Corrected.getCorrection());
976  if (FirstDecl)
977  Result.addDecl(FirstDecl);
978 
979  // If we found an Objective-C instance variable, let
980  // LookupInObjCMethod build the appropriate expression to
981  // reference the ivar.
982  // FIXME: This is a gross hack.
983  if (ObjCIvarDecl *Ivar = Result.getAsSingle<ObjCIvarDecl>()) {
984  Result.clear();
985  ExprResult E(LookupInObjCMethod(Result, S, Ivar->getIdentifier()));
986  return E;
987  }
988 
989  goto Corrected;
990  }
991  }
992 
993  // We failed to correct; just fall through and let the parser deal with it.
994  Result.suppressDiagnostics();
996 
998  // We performed name lookup into the current instantiation, and there were
999  // dependent bases, so we treat this result the same way as any other
1000  // dependent nested-name-specifier.
1001 
1002  // C++ [temp.res]p2:
1003  // A name used in a template declaration or definition and that is
1004  // dependent on a template-parameter is assumed not to name a type
1005  // unless the applicable name lookup finds a type name or the name is
1006  // qualified by the keyword typename.
1007  //
1008  // FIXME: If the next token is '<', we might want to ask the parser to
1009  // perform some heroics to see if we actually have a
1010  // template-argument-list, which would indicate a missing 'template'
1011  // keyword here.
1012  return ActOnDependentIdExpression(SS, /*TemplateKWLoc=*/SourceLocation(),
1013  NameInfo, IsAddressOfOperand,
1014  /*TemplateArgs=*/nullptr);
1015  }
1016 
1017  case LookupResult::Found:
1020  break;
1021 
1023  if (getLangOpts().CPlusPlus && NextToken.is(tok::less) &&
1024  hasAnyAcceptableTemplateNames(Result)) {
1025  // C++ [temp.local]p3:
1026  // A lookup that finds an injected-class-name (10.2) can result in an
1027  // ambiguity in certain cases (for example, if it is found in more than
1028  // one base class). If all of the injected-class-names that are found
1029  // refer to specializations of the same class template, and if the name
1030  // is followed by a template-argument-list, the reference refers to the
1031  // class template itself and not a specialization thereof, and is not
1032  // ambiguous.
1033  //
1034  // This filtering can make an ambiguous result into an unambiguous one,
1035  // so try again after filtering out template names.
1036  FilterAcceptableTemplateNames(Result);
1037  if (!Result.isAmbiguous()) {
1038  IsFilteredTemplateName = true;
1039  break;
1040  }
1041  }
1042 
1043  // Diagnose the ambiguity and return an error.
1044  return NameClassification::Error();
1045  }
1046 
1047  if (getLangOpts().CPlusPlus && NextToken.is(tok::less) &&
1048  (IsFilteredTemplateName || hasAnyAcceptableTemplateNames(Result))) {
1049  // C++ [temp.names]p3:
1050  // After name lookup (3.4) finds that a name is a template-name or that
1051  // an operator-function-id or a literal- operator-id refers to a set of
1052  // overloaded functions any member of which is a function template if
1053  // this is followed by a <, the < is always taken as the delimiter of a
1054  // template-argument-list and never as the less-than operator.
1055  if (!IsFilteredTemplateName)
1056  FilterAcceptableTemplateNames(Result);
1057 
1058  if (!Result.empty()) {
1059  bool IsFunctionTemplate;
1060  bool IsVarTemplate;
1061  TemplateName Template;
1062  if (Result.end() - Result.begin() > 1) {
1063  IsFunctionTemplate = true;
1064  Template = Context.getOverloadedTemplateName(Result.begin(),
1065  Result.end());
1066  } else {
1067  TemplateDecl *TD
1068  = cast<TemplateDecl>((*Result.begin())->getUnderlyingDecl());
1069  IsFunctionTemplate = isa<FunctionTemplateDecl>(TD);
1070  IsVarTemplate = isa<VarTemplateDecl>(TD);
1071 
1072  if (SS.isSet() && !SS.isInvalid())
1073  Template = Context.getQualifiedTemplateName(SS.getScopeRep(),
1074  /*TemplateKeyword=*/false,
1075  TD);
1076  else
1077  Template = TemplateName(TD);
1078  }
1079 
1080  if (IsFunctionTemplate) {
1081  // Function templates always go through overload resolution, at which
1082  // point we'll perform the various checks (e.g., accessibility) we need
1083  // to based on which function we selected.
1084  Result.suppressDiagnostics();
1085 
1086  return NameClassification::FunctionTemplate(Template);
1087  }
1088 
1089  return IsVarTemplate ? NameClassification::VarTemplate(Template)
1090  : NameClassification::TypeTemplate(Template);
1091  }
1092  }
1093 
1094  NamedDecl *FirstDecl = (*Result.begin())->getUnderlyingDecl();
1095  if (TypeDecl *Type = dyn_cast<TypeDecl>(FirstDecl)) {
1096  DiagnoseUseOfDecl(Type, NameLoc);
1097  MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
1098  QualType T = Context.getTypeDeclType(Type);
1099  if (SS.isNotEmpty())
1100  return buildNestedType(*this, SS, T, NameLoc);
1101  return ParsedType::make(T);
1102  }
1103 
1104  ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(FirstDecl);
1105  if (!Class) {
1106  // FIXME: It's unfortunate that we don't have a Type node for handling this.
1107  if (ObjCCompatibleAliasDecl *Alias =
1108  dyn_cast<ObjCCompatibleAliasDecl>(FirstDecl))
1109  Class = Alias->getClassInterface();
1110  }
1111 
1112  if (Class) {
1113  DiagnoseUseOfDecl(Class, NameLoc);
1114 
1115  if (NextToken.is(tok::period)) {
1116  // Interface. <something> is parsed as a property reference expression.
1117  // Just return "unknown" as a fall-through for now.
1118  Result.suppressDiagnostics();
1119  return NameClassification::Unknown();
1120  }
1121 
1122  QualType T = Context.getObjCInterfaceType(Class);
1123  return ParsedType::make(T);
1124  }
1125 
1126  // We can have a type template here if we're classifying a template argument.
1127  if (isa<TemplateDecl>(FirstDecl) && !isa<FunctionTemplateDecl>(FirstDecl) &&
1128  !isa<VarTemplateDecl>(FirstDecl))
1129  return NameClassification::TypeTemplate(
1130  TemplateName(cast<TemplateDecl>(FirstDecl)));
1131 
1132  // Check for a tag type hidden by a non-type decl in a few cases where it
1133  // seems likely a type is wanted instead of the non-type that was found.
1134  bool NextIsOp = NextToken.isOneOf(tok::amp, tok::star);
1135  if ((NextToken.is(tok::identifier) ||
1136  (NextIsOp &&
1137  FirstDecl->getUnderlyingDecl()->isFunctionOrFunctionTemplate())) &&
1138  isTagTypeWithMissingTag(*this, Result, S, SS, Name, NameLoc)) {
1139  TypeDecl *Type = Result.getAsSingle<TypeDecl>();
1140  DiagnoseUseOfDecl(Type, NameLoc);
1141  QualType T = Context.getTypeDeclType(Type);
1142  if (SS.isNotEmpty())
1143  return buildNestedType(*this, SS, T, NameLoc);
1144  return ParsedType::make(T);
1145  }
1146 
1147  if (FirstDecl->isCXXClassMember())
1148  return BuildPossibleImplicitMemberExpr(SS, SourceLocation(), Result,
1149  nullptr, S);
1150 
1151  bool ADL = UseArgumentDependentLookup(SS, Result, NextToken.is(tok::l_paren));
1152  return BuildDeclarationNameExpr(SS, Result, ADL);
1153 }
1154 
1157  auto *TD = Name.getAsTemplateDecl();
1158  if (!TD)
1159  return TemplateNameKindForDiagnostics::DependentTemplate;
1160  if (isa<ClassTemplateDecl>(TD))
1161  return TemplateNameKindForDiagnostics::ClassTemplate;
1162  if (isa<FunctionTemplateDecl>(TD))
1163  return TemplateNameKindForDiagnostics::FunctionTemplate;
1164  if (isa<VarTemplateDecl>(TD))
1165  return TemplateNameKindForDiagnostics::VarTemplate;
1166  if (isa<TypeAliasTemplateDecl>(TD))
1167  return TemplateNameKindForDiagnostics::AliasTemplate;
1168  if (isa<TemplateTemplateParmDecl>(TD))
1169  return TemplateNameKindForDiagnostics::TemplateTemplateParam;
1170  return TemplateNameKindForDiagnostics::DependentTemplate;
1171 }
1172 
1173 // Determines the context to return to after temporarily entering a
1174 // context. This depends in an unnecessarily complicated way on the
1175 // exact ordering of callbacks from the parser.
1177 
1178  // Functions defined inline within classes aren't parsed until we've
1179  // finished parsing the top-level class, so the top-level class is
1180  // the context we'll need to return to.
1181  // A Lambda call operator whose parent is a class must not be treated
1182  // as an inline member function. A Lambda can be used legally
1183  // either as an in-class member initializer or a default argument. These
1184  // are parsed once the class has been marked complete and so the containing
1185  // context would be the nested class (when the lambda is defined in one);
1186  // If the class is not complete, then the lambda is being used in an
1187  // ill-formed fashion (such as to specify the width of a bit-field, or
1188  // in an array-bound) - in which case we still want to return the
1189  // lexically containing DC (which could be a nested class).
1190  if (isa<FunctionDecl>(DC) && !isLambdaCallOperator(DC)) {
1191  DC = DC->getLexicalParent();
1192 
1193  // A function not defined within a class will always return to its
1194  // lexical context.
1195  if (!isa<CXXRecordDecl>(DC))
1196  return DC;
1197 
1198  // A C++ inline method/friend is parsed *after* the topmost class
1199  // it was declared in is fully parsed ("complete"); the topmost
1200  // class is the context we need to return to.
1201  while (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(DC->getLexicalParent()))
1202  DC = RD;
1203 
1204  // Return the declaration context of the topmost class the inline method is
1205  // declared in.
1206  return DC;
1207  }
1208 
1209  return DC->getLexicalParent();
1210 }
1211 
1213  assert(getContainingDC(DC) == CurContext &&
1214  "The next DeclContext should be lexically contained in the current one.");
1215  CurContext = DC;
1216  S->setEntity(DC);
1217 }
1218 
1220  assert(CurContext && "DeclContext imbalance!");
1221 
1222  CurContext = getContainingDC(CurContext);
1223  assert(CurContext && "Popped translation unit!");
1224 }
1225 
1227  Decl *D) {
1228  // Unlike PushDeclContext, the context to which we return is not necessarily
1229  // the containing DC of TD, because the new context will be some pre-existing
1230  // TagDecl definition instead of a fresh one.
1231  auto Result = static_cast<SkippedDefinitionContext>(CurContext);
1232  CurContext = cast<TagDecl>(D)->getDefinition();
1233  assert(CurContext && "skipping definition of undefined tag");
1234  // Start lookups from the parent of the current context; we don't want to look
1235  // into the pre-existing complete definition.
1236  S->setEntity(CurContext->getLookupParent());
1237  return Result;
1238 }
1239 
1241  CurContext = static_cast<decltype(CurContext)>(Context);
1242 }
1243 
1244 /// EnterDeclaratorContext - Used when we must lookup names in the context
1245 /// of a declarator's nested name specifier.
1246 ///
1248  // C++0x [basic.lookup.unqual]p13:
1249  // A name used in the definition of a static data member of class
1250  // X (after the qualified-id of the static member) is looked up as
1251  // if the name was used in a member function of X.
1252  // C++0x [basic.lookup.unqual]p14:
1253  // If a variable member of a namespace is defined outside of the
1254  // scope of its namespace then any name used in the definition of
1255  // the variable member (after the declarator-id) is looked up as
1256  // if the definition of the variable member occurred in its
1257  // namespace.
1258  // Both of these imply that we should push a scope whose context
1259  // is the semantic context of the declaration. We can't use
1260  // PushDeclContext here because that context is not necessarily
1261  // lexically contained in the current context. Fortunately,
1262  // the containing scope should have the appropriate information.
1263 
1264  assert(!S->getEntity() && "scope already has entity");
1265 
1266 #ifndef NDEBUG
1267  Scope *Ancestor = S->getParent();
1268  while (!Ancestor->getEntity()) Ancestor = Ancestor->getParent();
1269  assert(Ancestor->getEntity() == CurContext && "ancestor context mismatch");
1270 #endif
1271 
1272  CurContext = DC;
1273  S->setEntity(DC);
1274 }
1275 
1277  assert(S->getEntity() == CurContext && "Context imbalance!");
1278 
1279  // Switch back to the lexical context. The safety of this is
1280  // enforced by an assert in EnterDeclaratorContext.
1281  Scope *Ancestor = S->getParent();
1282  while (!Ancestor->getEntity()) Ancestor = Ancestor->getParent();
1283  CurContext = Ancestor->getEntity();
1284 
1285  // We don't need to do anything with the scope, which is going to
1286  // disappear.
1287 }
1288 
1290  // We assume that the caller has already called
1291  // ActOnReenterTemplateScope so getTemplatedDecl() works.
1292  FunctionDecl *FD = D->getAsFunction();
1293  if (!FD)
1294  return;
1295 
1296  // Same implementation as PushDeclContext, but enters the context
1297  // from the lexical parent, rather than the top-level class.
1298  assert(CurContext == FD->getLexicalParent() &&
1299  "The next DeclContext should be lexically contained in the current one.");
1300  CurContext = FD;
1301  S->setEntity(CurContext);
1302 
1303  for (unsigned P = 0, NumParams = FD->getNumParams(); P < NumParams; ++P) {
1304  ParmVarDecl *Param = FD->getParamDecl(P);
1305  // If the parameter has an identifier, then add it to the scope
1306  if (Param->getIdentifier()) {
1307  S->AddDecl(Param);
1308  IdResolver.AddDecl(Param);
1309  }
1310  }
1311 }
1312 
1314  // Same implementation as PopDeclContext, but returns to the lexical parent,
1315  // rather than the top-level class.
1316  assert(CurContext && "DeclContext imbalance!");
1317  CurContext = CurContext->getLexicalParent();
1318  assert(CurContext && "Popped translation unit!");
1319 }
1320 
1321 /// \brief Determine whether we allow overloading of the function
1322 /// PrevDecl with another declaration.
1323 ///
1324 /// This routine determines whether overloading is possible, not
1325 /// whether some new function is actually an overload. It will return
1326 /// true in C++ (where we can always provide overloads) or, as an
1327 /// extension, in C when the previous function is already an
1328 /// overloaded function declaration or has the "overloadable"
1329 /// attribute.
1331  ASTContext &Context,
1332  const FunctionDecl *New) {
1333  if (Context.getLangOpts().CPlusPlus)
1334  return true;
1335 
1336  if (Previous.getResultKind() == LookupResult::FoundOverloaded)
1337  return true;
1338 
1339  return Previous.getResultKind() == LookupResult::Found &&
1340  (Previous.getFoundDecl()->hasAttr<OverloadableAttr>() ||
1341  New->hasAttr<OverloadableAttr>());
1342 }
1343 
1344 /// Add this decl to the scope shadowed decl chains.
1345 void Sema::PushOnScopeChains(NamedDecl *D, Scope *S, bool AddToContext) {
1346  // Move up the scope chain until we find the nearest enclosing
1347  // non-transparent context. The declaration will be introduced into this
1348  // scope.
1349  while (S->getEntity() && S->getEntity()->isTransparentContext())
1350  S = S->getParent();
1351 
1352  // Add scoped declarations into their context, so that they can be
1353  // found later. Declarations without a context won't be inserted
1354  // into any context.
1355  if (AddToContext)
1356  CurContext->addDecl(D);
1357 
1358  // Out-of-line definitions shouldn't be pushed into scope in C++, unless they
1359  // are function-local declarations.
1360  if (getLangOpts().CPlusPlus && D->isOutOfLine() &&
1364  return;
1365 
1366  // Template instantiations should also not be pushed into scope.
1367  if (isa<FunctionDecl>(D) &&
1368  cast<FunctionDecl>(D)->isFunctionTemplateSpecialization())
1369  return;
1370 
1371  // If this replaces anything in the current scope,
1372  IdentifierResolver::iterator I = IdResolver.begin(D->getDeclName()),
1373  IEnd = IdResolver.end();
1374  for (; I != IEnd; ++I) {
1375  if (S->isDeclScope(*I) && D->declarationReplaces(*I)) {
1376  S->RemoveDecl(*I);
1377  IdResolver.RemoveDecl(*I);
1378 
1379  // Should only need to replace one decl.
1380  break;
1381  }
1382  }
1383 
1384  S->AddDecl(D);
1385 
1386  if (isa<LabelDecl>(D) && !cast<LabelDecl>(D)->isGnuLocal()) {
1387  // Implicitly-generated labels may end up getting generated in an order that
1388  // isn't strictly lexical, which breaks name lookup. Be careful to insert
1389  // the label at the appropriate place in the identifier chain.
1390  for (I = IdResolver.begin(D->getDeclName()); I != IEnd; ++I) {
1391  DeclContext *IDC = (*I)->getLexicalDeclContext()->getRedeclContext();
1392  if (IDC == CurContext) {
1393  if (!S->isDeclScope(*I))
1394  continue;
1395  } else if (IDC->Encloses(CurContext))
1396  break;
1397  }
1398 
1399  IdResolver.InsertDeclAfter(I, D);
1400  } else {
1401  IdResolver.AddDecl(D);
1402  }
1403 }
1404 
1406  if (IdResolver.tryAddTopLevelDecl(D, Name) && TUScope)
1407  TUScope->AddDecl(D);
1408 }
1409 
1411  bool AllowInlineNamespace) {
1412  return IdResolver.isDeclInScope(D, Ctx, S, AllowInlineNamespace);
1413 }
1414 
1416  DeclContext *TargetDC = DC->getPrimaryContext();
1417  do {
1418  if (DeclContext *ScopeDC = S->getEntity())
1419  if (ScopeDC->getPrimaryContext() == TargetDC)
1420  return S;
1421  } while ((S = S->getParent()));
1422 
1423  return nullptr;
1424 }
1425 
1427  DeclContext*,
1428  ASTContext&);
1429 
1430 /// Filters out lookup results that don't fall within the given scope
1431 /// as determined by isDeclInScope.
1433  bool ConsiderLinkage,
1434  bool AllowInlineNamespace) {
1436  while (F.hasNext()) {
1437  NamedDecl *D = F.next();
1438 
1439  if (isDeclInScope(D, Ctx, S, AllowInlineNamespace))
1440  continue;
1441 
1442  if (ConsiderLinkage && isOutOfScopePreviousDeclaration(D, Ctx, Context))
1443  continue;
1444 
1445  F.erase();
1446  }
1447 
1448  F.done();
1449 }
1450 
1451 /// We've determined that \p New is a redeclaration of \p Old. Check that they
1452 /// have compatible owning modules.
1454  // FIXME: The Modules TS is not clear about how friend declarations are
1455  // to be treated. It's not meaningful to have different owning modules for
1456  // linkage in redeclarations of the same entity, so for now allow the
1457  // redeclaration and change the owning modules to match.
1458  if (New->getFriendObjectKind() &&
1461  makeMergedDefinitionVisible(New);
1462  return false;
1463  }
1464 
1465  Module *NewM = New->getOwningModule();
1466  Module *OldM = Old->getOwningModule();
1467  if (NewM == OldM)
1468  return false;
1469 
1470  // FIXME: Check proclaimed-ownership-declarations here too.
1471  bool NewIsModuleInterface = NewM && NewM->Kind == Module::ModuleInterfaceUnit;
1472  bool OldIsModuleInterface = OldM && OldM->Kind == Module::ModuleInterfaceUnit;
1473  if (NewIsModuleInterface || OldIsModuleInterface) {
1474  // C++ Modules TS [basic.def.odr] 6.2/6.7 [sic]:
1475  // if a declaration of D [...] appears in the purview of a module, all
1476  // other such declarations shall appear in the purview of the same module
1477  Diag(New->getLocation(), diag::err_mismatched_owning_module)
1478  << New
1479  << NewIsModuleInterface
1480  << (NewIsModuleInterface ? NewM->getFullModuleName() : "")
1481  << OldIsModuleInterface
1482  << (OldIsModuleInterface ? OldM->getFullModuleName() : "");
1483  Diag(Old->getLocation(), diag::note_previous_declaration);
1484  New->setInvalidDecl();
1485  return true;
1486  }
1487 
1488  return false;
1489 }
1490 
1491 static bool isUsingDecl(NamedDecl *D) {
1492  return isa<UsingShadowDecl>(D) ||
1493  isa<UnresolvedUsingTypenameDecl>(D) ||
1494  isa<UnresolvedUsingValueDecl>(D);
1495 }
1496 
1497 /// Removes using shadow declarations from the lookup results.
1500  while (F.hasNext())
1501  if (isUsingDecl(F.next()))
1502  F.erase();
1503 
1504  F.done();
1505 }
1506 
1507 /// \brief Check for this common pattern:
1508 /// @code
1509 /// class S {
1510 /// S(const S&); // DO NOT IMPLEMENT
1511 /// void operator=(const S&); // DO NOT IMPLEMENT
1512 /// };
1513 /// @endcode
1515  // FIXME: Should check for private access too but access is set after we get
1516  // the decl here.
1518  return false;
1519 
1520  if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(D))
1521  return CD->isCopyConstructor();
1522  if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D))
1523  return Method->isCopyAssignmentOperator();
1524  return false;
1525 }
1526 
1527 // We need this to handle
1528 //
1529 // typedef struct {
1530 // void *foo() { return 0; }
1531 // } A;
1532 //
1533 // When we see foo we don't know if after the typedef we will get 'A' or '*A'
1534 // for example. If 'A', foo will have external linkage. If we have '*A',
1535 // foo will have no linkage. Since we can't know until we get to the end
1536 // of the typedef, this function finds out if D might have non-external linkage.
1537 // Callers should verify at the end of the TU if it D has external linkage or
1538 // not.
1539 bool Sema::mightHaveNonExternalLinkage(const DeclaratorDecl *D) {
1540  const DeclContext *DC = D->getDeclContext();
1541  while (!DC->isTranslationUnit()) {
1542  if (const RecordDecl *RD = dyn_cast<RecordDecl>(DC)){
1543  if (!RD->hasNameForLinkage())
1544  return true;
1545  }
1546  DC = DC->getParent();
1547  }
1548 
1549  return !D->isExternallyVisible();
1550 }
1551 
1552 // FIXME: This needs to be refactored; some other isInMainFile users want
1553 // these semantics.
1554 static bool isMainFileLoc(const Sema &S, SourceLocation Loc) {
1555  if (S.TUKind != TU_Complete)
1556  return false;
1557  return S.SourceMgr.isInMainFile(Loc);
1558 }
1559 
1561  assert(D);
1562 
1563  if (D->isInvalidDecl() || D->isUsed() || D->hasAttr<UnusedAttr>())
1564  return false;
1565 
1566  // Ignore all entities declared within templates, and out-of-line definitions
1567  // of members of class templates.
1568  if (D->getDeclContext()->isDependentContext() ||
1570  return false;
1571 
1572  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
1573  if (FD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
1574  return false;
1575  // A non-out-of-line declaration of a member specialization was implicitly
1576  // instantiated; it's the out-of-line declaration that we're interested in.
1577  if (FD->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&
1578  FD->getMemberSpecializationInfo() && !FD->isOutOfLine())
1579  return false;
1580 
1581  if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
1582  if (MD->isVirtual() || IsDisallowedCopyOrAssign(MD))
1583  return false;
1584  } else {
1585  // 'static inline' functions are defined in headers; don't warn.
1586  if (FD->isInlined() && !isMainFileLoc(*this, FD->getLocation()))
1587  return false;
1588  }
1589 
1590  if (FD->doesThisDeclarationHaveABody() &&
1591  Context.DeclMustBeEmitted(FD))
1592  return false;
1593  } else if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
1594  // Constants and utility variables are defined in headers with internal
1595  // linkage; don't warn. (Unlike functions, there isn't a convenient marker
1596  // like "inline".)
1597  if (!isMainFileLoc(*this, VD->getLocation()))
1598  return false;
1599 
1600  if (Context.DeclMustBeEmitted(VD))
1601  return false;
1602 
1603  if (VD->isStaticDataMember() &&
1604  VD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
1605  return false;
1606  if (VD->isStaticDataMember() &&
1607  VD->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&
1608  VD->getMemberSpecializationInfo() && !VD->isOutOfLine())
1609  return false;
1610 
1611  if (VD->isInline() && !isMainFileLoc(*this, VD->getLocation()))
1612  return false;
1613  } else {
1614  return false;
1615  }
1616 
1617  // Only warn for unused decls internal to the translation unit.
1618  // FIXME: This seems like a bogus check; it suppresses -Wunused-function
1619  // for inline functions defined in the main source file, for instance.
1620  return mightHaveNonExternalLinkage(D);
1621 }
1622 
1624  if (!D)
1625  return;
1626 
1627  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
1628  const FunctionDecl *First = FD->getFirstDecl();
1629  if (FD != First && ShouldWarnIfUnusedFileScopedDecl(First))
1630  return; // First should already be in the vector.
1631  }
1632 
1633  if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
1634  const VarDecl *First = VD->getFirstDecl();
1635  if (VD != First && ShouldWarnIfUnusedFileScopedDecl(First))
1636  return; // First should already be in the vector.
1637  }
1638 
1639  if (ShouldWarnIfUnusedFileScopedDecl(D))
1640  UnusedFileScopedDecls.push_back(D);
1641 }
1642 
1643 static bool ShouldDiagnoseUnusedDecl(const NamedDecl *D) {
1644  if (D->isInvalidDecl())
1645  return false;
1646 
1647  bool Referenced = false;
1648  if (auto *DD = dyn_cast<DecompositionDecl>(D)) {
1649  // For a decomposition declaration, warn if none of the bindings are
1650  // referenced, instead of if the variable itself is referenced (which
1651  // it is, by the bindings' expressions).
1652  for (auto *BD : DD->bindings()) {
1653  if (BD->isReferenced()) {
1654  Referenced = true;
1655  break;
1656  }
1657  }
1658  } else if (!D->getDeclName()) {
1659  return false;
1660  } else if (D->isReferenced() || D->isUsed()) {
1661  Referenced = true;
1662  }
1663 
1664  if (Referenced || D->hasAttr<UnusedAttr>() ||
1665  D->hasAttr<ObjCPreciseLifetimeAttr>())
1666  return false;
1667 
1668  if (isa<LabelDecl>(D))
1669  return true;
1670 
1671  // Except for labels, we only care about unused decls that are local to
1672  // functions.
1673  bool WithinFunction = D->getDeclContext()->isFunctionOrMethod();
1674  if (const auto *R = dyn_cast<CXXRecordDecl>(D->getDeclContext()))
1675  // For dependent types, the diagnostic is deferred.
1676  WithinFunction =
1677  WithinFunction || (R->isLocalClass() && !R->isDependentType());
1678  if (!WithinFunction)
1679  return false;
1680 
1681  if (isa<TypedefNameDecl>(D))
1682  return true;
1683 
1684  // White-list anything that isn't a local variable.
1685  if (!isa<VarDecl>(D) || isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D))
1686  return false;
1687 
1688  // Types of valid local variables should be complete, so this should succeed.
1689  if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
1690 
1691  // White-list anything with an __attribute__((unused)) type.
1692  const auto *Ty = VD->getType().getTypePtr();
1693 
1694  // Only look at the outermost level of typedef.
1695  if (const TypedefType *TT = Ty->getAs<TypedefType>()) {
1696  if (TT->getDecl()->hasAttr<UnusedAttr>())
1697  return false;
1698  }
1699 
1700  // If we failed to complete the type for some reason, or if the type is
1701  // dependent, don't diagnose the variable.
1702  if (Ty->isIncompleteType() || Ty->isDependentType())
1703  return false;
1704 
1705  // Look at the element type to ensure that the warning behaviour is
1706  // consistent for both scalars and arrays.
1707  Ty = Ty->getBaseElementTypeUnsafe();
1708 
1709  if (const TagType *TT = Ty->getAs<TagType>()) {
1710  const TagDecl *Tag = TT->getDecl();
1711  if (Tag->hasAttr<UnusedAttr>())
1712  return false;
1713 
1714  if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Tag)) {
1715  if (!RD->hasTrivialDestructor() && !RD->hasAttr<WarnUnusedAttr>())
1716  return false;
1717 
1718  if (const Expr *Init = VD->getInit()) {
1719  if (const ExprWithCleanups *Cleanups =
1720  dyn_cast<ExprWithCleanups>(Init))
1721  Init = Cleanups->getSubExpr();
1722  const CXXConstructExpr *Construct =
1723  dyn_cast<CXXConstructExpr>(Init);
1724  if (Construct && !Construct->isElidable()) {
1725  CXXConstructorDecl *CD = Construct->getConstructor();
1726  if (!CD->isTrivial() && !RD->hasAttr<WarnUnusedAttr>() &&
1727  (VD->getInit()->isValueDependent() || !VD->evaluateValue()))
1728  return false;
1729  }
1730  }
1731  }
1732  }
1733 
1734  // TODO: __attribute__((unused)) templates?
1735  }
1736 
1737  return true;
1738 }
1739 
1740 static void GenerateFixForUnusedDecl(const NamedDecl *D, ASTContext &Ctx,
1741  FixItHint &Hint) {
1742  if (isa<LabelDecl>(D)) {
1744  tok::colon, Ctx.getSourceManager(), Ctx.getLangOpts(), true);
1745  if (AfterColon.isInvalid())
1746  return;
1748  getCharRange(D->getLocStart(), AfterColon));
1749  }
1750 }
1751 
1753  if (D->getTypeForDecl()->isDependentType())
1754  return;
1755 
1756  for (auto *TmpD : D->decls()) {
1757  if (const auto *T = dyn_cast<TypedefNameDecl>(TmpD))
1758  DiagnoseUnusedDecl(T);
1759  else if(const auto *R = dyn_cast<RecordDecl>(TmpD))
1760  DiagnoseUnusedNestedTypedefs(R);
1761  }
1762 }
1763 
1764 /// DiagnoseUnusedDecl - Emit warnings about declarations that are not used
1765 /// unless they are marked attr(unused).
1767  if (!ShouldDiagnoseUnusedDecl(D))
1768  return;
1769 
1770  if (auto *TD = dyn_cast<TypedefNameDecl>(D)) {
1771  // typedefs can be referenced later on, so the diagnostics are emitted
1772  // at end-of-translation-unit.
1773  UnusedLocalTypedefNameCandidates.insert(TD);
1774  return;
1775  }
1776 
1777  FixItHint Hint;
1778  GenerateFixForUnusedDecl(D, Context, Hint);
1779 
1780  unsigned DiagID;
1781  if (isa<VarDecl>(D) && cast<VarDecl>(D)->isExceptionVariable())
1782  DiagID = diag::warn_unused_exception_param;
1783  else if (isa<LabelDecl>(D))
1784  DiagID = diag::warn_unused_label;
1785  else
1786  DiagID = diag::warn_unused_variable;
1787 
1788  Diag(D->getLocation(), DiagID) << D << Hint;
1789 }
1790 
1791 static void CheckPoppedLabel(LabelDecl *L, Sema &S) {
1792  // Verify that we have no forward references left. If so, there was a goto
1793  // or address of a label taken, but no definition of it. Label fwd
1794  // definitions are indicated with a null substmt which is also not a resolved
1795  // MS inline assembly label name.
1796  bool Diagnose = false;
1797  if (L->isMSAsmLabel())
1798  Diagnose = !L->isResolvedMSAsmLabel();
1799  else
1800  Diagnose = L->getStmt() == nullptr;
1801  if (Diagnose)
1802  S.Diag(L->getLocation(), diag::err_undeclared_label_use) <<L->getDeclName();
1803 }
1804 
1806  S->mergeNRVOIntoParent();
1807 
1808  if (S->decl_empty()) return;
1809  assert((S->getFlags() & (Scope::DeclScope | Scope::TemplateParamScope)) &&
1810  "Scope shouldn't contain decls!");
1811 
1812  for (auto *TmpD : S->decls()) {
1813  assert(TmpD && "This decl didn't get pushed??");
1814 
1815  assert(isa<NamedDecl>(TmpD) && "Decl isn't NamedDecl?");
1816  NamedDecl *D = cast<NamedDecl>(TmpD);
1817 
1818  // Diagnose unused variables in this scope.
1819  if (!S->hasUnrecoverableErrorOccurred()) {
1820  DiagnoseUnusedDecl(D);
1821  if (const auto *RD = dyn_cast<RecordDecl>(D))
1822  DiagnoseUnusedNestedTypedefs(RD);
1823  }
1824 
1825  if (!D->getDeclName()) continue;
1826 
1827  // If this was a forward reference to a label, verify it was defined.
1828  if (LabelDecl *LD = dyn_cast<LabelDecl>(D))
1829  CheckPoppedLabel(LD, *this);
1830 
1831  // Remove this name from our lexical scope, and warn on it if we haven't
1832  // already.
1833  IdResolver.RemoveDecl(D);
1834  auto ShadowI = ShadowingDecls.find(D);
1835  if (ShadowI != ShadowingDecls.end()) {
1836  if (const auto *FD = dyn_cast<FieldDecl>(ShadowI->second)) {
1837  Diag(D->getLocation(), diag::warn_ctor_parm_shadows_field)
1838  << D << FD << FD->getParent();
1839  Diag(FD->getLocation(), diag::note_previous_declaration);
1840  }
1841  ShadowingDecls.erase(ShadowI);
1842  }
1843  }
1844 }
1845 
1846 /// \brief Look for an Objective-C class in the translation unit.
1847 ///
1848 /// \param Id The name of the Objective-C class we're looking for. If
1849 /// typo-correction fixes this name, the Id will be updated
1850 /// to the fixed name.
1851 ///
1852 /// \param IdLoc The location of the name in the translation unit.
1853 ///
1854 /// \param DoTypoCorrection If true, this routine will attempt typo correction
1855 /// if there is no class with the given name.
1856 ///
1857 /// \returns The declaration of the named Objective-C class, or NULL if the
1858 /// class could not be found.
1860  SourceLocation IdLoc,
1861  bool DoTypoCorrection) {
1862  // The third "scope" argument is 0 since we aren't enabling lazy built-in
1863  // creation from this context.
1864  NamedDecl *IDecl = LookupSingleName(TUScope, Id, IdLoc, LookupOrdinaryName);
1865 
1866  if (!IDecl && DoTypoCorrection) {
1867  // Perform typo correction at the given location, but only if we
1868  // find an Objective-C class name.
1869  if (TypoCorrection C = CorrectTypo(
1870  DeclarationNameInfo(Id, IdLoc), LookupOrdinaryName, TUScope, nullptr,
1871  llvm::make_unique<DeclFilterCCC<ObjCInterfaceDecl>>(),
1872  CTK_ErrorRecovery)) {
1873  diagnoseTypo(C, PDiag(diag::err_undef_interface_suggest) << Id);
1874  IDecl = C.getCorrectionDeclAs<ObjCInterfaceDecl>();
1875  Id = IDecl->getIdentifier();
1876  }
1877  }
1878  ObjCInterfaceDecl *Def = dyn_cast_or_null<ObjCInterfaceDecl>(IDecl);
1879  // This routine must always return a class definition, if any.
1880  if (Def && Def->getDefinition())
1881  Def = Def->getDefinition();
1882  return Def;
1883 }
1884 
1885 /// getNonFieldDeclScope - Retrieves the innermost scope, starting
1886 /// from S, where a non-field would be declared. This routine copes
1887 /// with the difference between C and C++ scoping rules in structs and
1888 /// unions. For example, the following code is well-formed in C but
1889 /// ill-formed in C++:
1890 /// @code
1891 /// struct S6 {
1892 /// enum { BAR } e;
1893 /// };
1894 ///
1895 /// void test_S6() {
1896 /// struct S6 a;
1897 /// a.e = BAR;
1898 /// }
1899 /// @endcode
1900 /// For the declaration of BAR, this routine will return a different
1901 /// scope. The scope S will be the scope of the unnamed enumeration
1902 /// within S6. In C++, this routine will return the scope associated
1903 /// with S6, because the enumeration's scope is a transparent
1904 /// context but structures can contain non-field names. In C, this
1905 /// routine will return the translation unit scope, since the
1906 /// enumeration's scope is a transparent context and structures cannot
1907 /// contain non-field names.
1909  while (((S->getFlags() & Scope::DeclScope) == 0) ||
1910  (S->getEntity() && S->getEntity()->isTransparentContext()) ||
1911  (S->isClassScope() && !getLangOpts().CPlusPlus))
1912  S = S->getParent();
1913  return S;
1914 }
1915 
1916 /// \brief Looks up the declaration of "struct objc_super" and
1917 /// saves it for later use in building builtin declaration of
1918 /// objc_msgSendSuper and objc_msgSendSuper_stret. If no such
1919 /// pre-existing declaration exists no action takes place.
1920 static void LookupPredefedObjCSuperType(Sema &ThisSema, Scope *S,
1921  IdentifierInfo *II) {
1922  if (!II->isStr("objc_msgSendSuper"))
1923  return;
1924  ASTContext &Context = ThisSema.Context;
1925 
1926  LookupResult Result(ThisSema, &Context.Idents.get("objc_super"),
1928  ThisSema.LookupName(Result, S);
1929  if (Result.getResultKind() == LookupResult::Found)
1930  if (const TagDecl *TD = Result.getAsSingle<TagDecl>())
1931  Context.setObjCSuperType(Context.getTagDeclType(TD));
1932 }
1933 
1935  switch (Error) {
1936  case ASTContext::GE_None:
1937  return "";
1939  return "stdio.h";
1941  return "setjmp.h";
1943  return "ucontext.h";
1944  }
1945  llvm_unreachable("unhandled error kind");
1946 }
1947 
1948 /// LazilyCreateBuiltin - The specified Builtin-ID was first used at
1949 /// file scope. lazily create a decl for it. ForRedeclaration is true
1950 /// if we're creating this built-in in anticipation of redeclaring the
1951 /// built-in.
1953  Scope *S, bool ForRedeclaration,
1954  SourceLocation Loc) {
1955  LookupPredefedObjCSuperType(*this, S, II);
1956 
1958  QualType R = Context.GetBuiltinType(ID, Error);
1959  if (Error) {
1960  if (ForRedeclaration)
1961  Diag(Loc, diag::warn_implicit_decl_requires_sysheader)
1962  << getHeaderName(Error) << Context.BuiltinInfo.getName(ID);
1963  return nullptr;
1964  }
1965 
1966  if (!ForRedeclaration &&
1967  (Context.BuiltinInfo.isPredefinedLibFunction(ID) ||
1968  Context.BuiltinInfo.isHeaderDependentFunction(ID))) {
1969  Diag(Loc, diag::ext_implicit_lib_function_decl)
1970  << Context.BuiltinInfo.getName(ID) << R;
1971  if (Context.BuiltinInfo.getHeaderName(ID) &&
1972  !Diags.isIgnored(diag::ext_implicit_lib_function_decl, Loc))
1973  Diag(Loc, diag::note_include_header_or_declare)
1974  << Context.BuiltinInfo.getHeaderName(ID)
1975  << Context.BuiltinInfo.getName(ID);
1976  }
1977 
1978  if (R.isNull())
1979  return nullptr;
1980 
1982  if (getLangOpts().CPlusPlus) {
1983  LinkageSpecDecl *CLinkageDecl =
1984  LinkageSpecDecl::Create(Context, Parent, Loc, Loc,
1985  LinkageSpecDecl::lang_c, false);
1986  CLinkageDecl->setImplicit();
1987  Parent->addDecl(CLinkageDecl);
1988  Parent = CLinkageDecl;
1989  }
1990 
1991  FunctionDecl *New = FunctionDecl::Create(Context,
1992  Parent,
1993  Loc, Loc, II, R, /*TInfo=*/nullptr,
1994  SC_Extern,
1995  false,
1996  R->isFunctionProtoType());
1997  New->setImplicit();
1998 
1999  // Create Decl objects for each parameter, adding them to the
2000  // FunctionDecl.
2001  if (const FunctionProtoType *FT = dyn_cast<FunctionProtoType>(R)) {
2003  for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) {
2004  ParmVarDecl *parm =
2006  nullptr, FT->getParamType(i), /*TInfo=*/nullptr,
2007  SC_None, nullptr);
2008  parm->setScopeInfo(0, i);
2009  Params.push_back(parm);
2010  }
2011  New->setParams(Params);
2012  }
2013 
2014  AddKnownFunctionAttributes(New);
2015  RegisterLocallyScopedExternCDecl(New, S);
2016 
2017  // TUScope is the translation-unit scope to insert this function into.
2018  // FIXME: This is hideous. We need to teach PushOnScopeChains to
2019  // relate Scopes to DeclContexts, and probably eliminate CurContext
2020  // entirely, but we're not there yet.
2021  DeclContext *SavedContext = CurContext;
2022  CurContext = Parent;
2023  PushOnScopeChains(New, TUScope);
2024  CurContext = SavedContext;
2025  return New;
2026 }
2027 
2028 /// Typedef declarations don't have linkage, but they still denote the same
2029 /// entity if their types are the same.
2030 /// FIXME: This is notionally doing the same thing as ASTReaderDecl's
2031 /// isSameEntity.
2035  // This is only interesting when modules are enabled.
2036  if (!S.getLangOpts().Modules && !S.getLangOpts().ModulesLocalVisibility)
2037  return;
2038 
2039  // Empty sets are uninteresting.
2040  if (Previous.empty())
2041  return;
2042 
2043  LookupResult::Filter Filter = Previous.makeFilter();
2044  while (Filter.hasNext()) {
2045  NamedDecl *Old = Filter.next();
2046 
2047  // Non-hidden declarations are never ignored.
2048  if (S.isVisible(Old))
2049  continue;
2050 
2051  // Declarations of the same entity are not ignored, even if they have
2052  // different linkages.
2053  if (auto *OldTD = dyn_cast<TypedefNameDecl>(Old)) {
2054  if (S.Context.hasSameType(OldTD->getUnderlyingType(),
2055  Decl->getUnderlyingType()))
2056  continue;
2057 
2058  // If both declarations give a tag declaration a typedef name for linkage
2059  // purposes, then they declare the same entity.
2060  if (OldTD->getAnonDeclWithTypedefName(/*AnyRedecl*/true) &&
2062  continue;
2063  }
2064 
2065  Filter.erase();
2066  }
2067 
2068  Filter.done();
2069 }
2070 
2072  QualType OldType;
2073  if (TypedefNameDecl *OldTypedef = dyn_cast<TypedefNameDecl>(Old))
2074  OldType = OldTypedef->getUnderlyingType();
2075  else
2076  OldType = Context.getTypeDeclType(Old);
2077  QualType NewType = New->getUnderlyingType();
2078 
2079  if (NewType->isVariablyModifiedType()) {
2080  // Must not redefine a typedef with a variably-modified type.
2081  int Kind = isa<TypeAliasDecl>(Old) ? 1 : 0;
2082  Diag(New->getLocation(), diag::err_redefinition_variably_modified_typedef)
2083  << Kind << NewType;
2084  if (Old->getLocation().isValid())
2085  notePreviousDefinition(Old, New->getLocation());
2086  New->setInvalidDecl();
2087  return true;
2088  }
2089 
2090  if (OldType != NewType &&
2091  !OldType->isDependentType() &&
2092  !NewType->isDependentType() &&
2093  !Context.hasSameType(OldType, NewType)) {
2094  int Kind = isa<TypeAliasDecl>(Old) ? 1 : 0;
2095  Diag(New->getLocation(), diag::err_redefinition_different_typedef)
2096  << Kind << NewType << OldType;
2097  if (Old->getLocation().isValid())
2098  notePreviousDefinition(Old, New->getLocation());
2099  New->setInvalidDecl();
2100  return true;
2101  }
2102  return false;
2103 }
2104 
2105 /// MergeTypedefNameDecl - We just parsed a typedef 'New' which has the
2106 /// same name and scope as a previous declaration 'Old'. Figure out
2107 /// how to resolve this situation, merging decls or emitting
2108 /// diagnostics as appropriate. If there was an error, set New to be invalid.
2109 ///
2111  LookupResult &OldDecls) {
2112  // If the new decl is known invalid already, don't bother doing any
2113  // merging checks.
2114  if (New->isInvalidDecl()) return;
2115 
2116  // Allow multiple definitions for ObjC built-in typedefs.
2117  // FIXME: Verify the underlying types are equivalent!
2118  if (getLangOpts().ObjC1) {
2119  const IdentifierInfo *TypeID = New->getIdentifier();
2120  switch (TypeID->getLength()) {
2121  default: break;
2122  case 2:
2123  {
2124  if (!TypeID->isStr("id"))
2125  break;
2126  QualType T = New->getUnderlyingType();
2127  if (!T->isPointerType())
2128  break;
2129  if (!T->isVoidPointerType()) {
2130  QualType PT = T->getAs<PointerType>()->getPointeeType();
2131  if (!PT->isStructureType())
2132  break;
2133  }
2134  Context.setObjCIdRedefinitionType(T);
2135  // Install the built-in type for 'id', ignoring the current definition.
2136  New->setTypeForDecl(Context.getObjCIdType().getTypePtr());
2137  return;
2138  }
2139  case 5:
2140  if (!TypeID->isStr("Class"))
2141  break;
2143  // Install the built-in type for 'Class', ignoring the current definition.
2144  New->setTypeForDecl(Context.getObjCClassType().getTypePtr());
2145  return;
2146  case 3:
2147  if (!TypeID->isStr("SEL"))
2148  break;
2150  // Install the built-in type for 'SEL', ignoring the current definition.
2151  New->setTypeForDecl(Context.getObjCSelType().getTypePtr());
2152  return;
2153  }
2154  // Fall through - the typedef name was not a builtin type.
2155  }
2156 
2157  // Verify the old decl was also a type.
2158  TypeDecl *Old = OldDecls.getAsSingle<TypeDecl>();
2159  if (!Old) {
2160  Diag(New->getLocation(), diag::err_redefinition_different_kind)
2161  << New->getDeclName();
2162 
2163  NamedDecl *OldD = OldDecls.getRepresentativeDecl();
2164  if (OldD->getLocation().isValid())
2165  notePreviousDefinition(OldD, New->getLocation());
2166 
2167  return New->setInvalidDecl();
2168  }
2169 
2170  // If the old declaration is invalid, just give up here.
2171  if (Old->isInvalidDecl())
2172  return New->setInvalidDecl();
2173 
2174  if (auto *OldTD = dyn_cast<TypedefNameDecl>(Old)) {
2175  auto *OldTag = OldTD->getAnonDeclWithTypedefName(/*AnyRedecl*/true);
2176  auto *NewTag = New->getAnonDeclWithTypedefName();
2177  NamedDecl *Hidden = nullptr;
2178  if (OldTag && NewTag &&
2179  OldTag->getCanonicalDecl() != NewTag->getCanonicalDecl() &&
2180  !hasVisibleDefinition(OldTag, &Hidden)) {
2181  // There is a definition of this tag, but it is not visible. Use it
2182  // instead of our tag.
2183  New->setTypeForDecl(OldTD->getTypeForDecl());
2184  if (OldTD->isModed())
2185  New->setModedTypeSourceInfo(OldTD->getTypeSourceInfo(),
2186  OldTD->getUnderlyingType());
2187  else
2188  New->setTypeSourceInfo(OldTD->getTypeSourceInfo());
2189 
2190  // Make the old tag definition visible.
2191  makeMergedDefinitionVisible(Hidden);
2192 
2193  // If this was an unscoped enumeration, yank all of its enumerators
2194  // out of the scope.
2195  if (isa<EnumDecl>(NewTag)) {
2196  Scope *EnumScope = getNonFieldDeclScope(S);
2197  for (auto *D : NewTag->decls()) {
2198  auto *ED = cast<EnumConstantDecl>(D);
2199  assert(EnumScope->isDeclScope(ED));
2200  EnumScope->RemoveDecl(ED);
2201  IdResolver.RemoveDecl(ED);
2202  ED->getLexicalDeclContext()->removeDecl(ED);
2203  }
2204  }
2205  }
2206  }
2207 
2208  // If the typedef types are not identical, reject them in all languages and
2209  // with any extensions enabled.
2210  if (isIncompatibleTypedef(Old, New))
2211  return;
2212 
2213  // The types match. Link up the redeclaration chain and merge attributes if
2214  // the old declaration was a typedef.
2215  if (TypedefNameDecl *Typedef = dyn_cast<TypedefNameDecl>(Old)) {
2216  New->setPreviousDecl(Typedef);
2217  mergeDeclAttributes(New, Old);
2218  }
2219 
2220  if (getLangOpts().MicrosoftExt)
2221  return;
2222 
2223  if (getLangOpts().CPlusPlus) {
2224  // C++ [dcl.typedef]p2:
2225  // In a given non-class scope, a typedef specifier can be used to
2226  // redefine the name of any type declared in that scope to refer
2227  // to the type to which it already refers.
2228  if (!isa<CXXRecordDecl>(CurContext))
2229  return;
2230 
2231  // C++0x [dcl.typedef]p4:
2232  // In a given class scope, a typedef specifier can be used to redefine
2233  // any class-name declared in that scope that is not also a typedef-name
2234  // to refer to the type to which it already refers.
2235  //
2236  // This wording came in via DR424, which was a correction to the
2237  // wording in DR56, which accidentally banned code like:
2238  //
2239  // struct S {
2240  // typedef struct A { } A;
2241  // };
2242  //
2243  // in the C++03 standard. We implement the C++0x semantics, which
2244  // allow the above but disallow
2245  //
2246  // struct S {
2247  // typedef int I;
2248  // typedef int I;
2249  // };
2250  //
2251  // since that was the intent of DR56.
2252  if (!isa<TypedefNameDecl>(Old))
2253  return;
2254 
2255  Diag(New->getLocation(), diag::err_redefinition)
2256  << New->getDeclName();
2257  notePreviousDefinition(Old, New->getLocation());
2258  return New->setInvalidDecl();
2259  }
2260 
2261  // Modules always permit redefinition of typedefs, as does C11.
2262  if (getLangOpts().Modules || getLangOpts().C11)
2263  return;
2264 
2265  // If we have a redefinition of a typedef in C, emit a warning. This warning
2266  // is normally mapped to an error, but can be controlled with
2267  // -Wtypedef-redefinition. If either the original or the redefinition is
2268  // in a system header, don't emit this for compatibility with GCC.
2269  if (getDiagnostics().getSuppressSystemWarnings() &&
2270  // Some standard types are defined implicitly in Clang (e.g. OpenCL).
2271  (Old->isImplicit() ||
2272  Context.getSourceManager().isInSystemHeader(Old->getLocation()) ||
2273  Context.getSourceManager().isInSystemHeader(New->getLocation())))
2274  return;
2275 
2276  Diag(New->getLocation(), diag::ext_redefinition_of_typedef)
2277  << New->getDeclName();
2278  notePreviousDefinition(Old, New->getLocation());
2279 }
2280 
2281 /// DeclhasAttr - returns true if decl Declaration already has the target
2282 /// attribute.
2283 static bool DeclHasAttr(const Decl *D, const Attr *A) {
2284  const OwnershipAttr *OA = dyn_cast<OwnershipAttr>(A);
2285  const AnnotateAttr *Ann = dyn_cast<AnnotateAttr>(A);
2286  for (const auto *i : D->attrs())
2287  if (i->getKind() == A->getKind()) {
2288  if (Ann) {
2289  if (Ann->getAnnotation() == cast<AnnotateAttr>(i)->getAnnotation())
2290  return true;
2291  continue;
2292  }
2293  // FIXME: Don't hardcode this check
2294  if (OA && isa<OwnershipAttr>(i))
2295  return OA->getOwnKind() == cast<OwnershipAttr>(i)->getOwnKind();
2296  return true;
2297  }
2298 
2299  return false;
2300 }
2301 
2303  if (VarDecl *VD = dyn_cast<VarDecl>(D))
2304  return VD->isThisDeclarationADefinition();
2305  if (TagDecl *TD = dyn_cast<TagDecl>(D))
2306  return TD->isCompleteDefinition() || TD->isBeingDefined();
2307  return true;
2308 }
2309 
2310 /// Merge alignment attributes from \p Old to \p New, taking into account the
2311 /// special semantics of C11's _Alignas specifier and C++11's alignas attribute.
2312 ///
2313 /// \return \c true if any attributes were added to \p New.
2314 static bool mergeAlignedAttrs(Sema &S, NamedDecl *New, Decl *Old) {
2315  // Look for alignas attributes on Old, and pick out whichever attribute
2316  // specifies the strictest alignment requirement.
2317  AlignedAttr *OldAlignasAttr = nullptr;
2318  AlignedAttr *OldStrictestAlignAttr = nullptr;
2319  unsigned OldAlign = 0;
2320  for (auto *I : Old->specific_attrs<AlignedAttr>()) {
2321  // FIXME: We have no way of representing inherited dependent alignments
2322  // in a case like:
2323  // template<int A, int B> struct alignas(A) X;
2324  // template<int A, int B> struct alignas(B) X {};
2325  // For now, we just ignore any alignas attributes which are not on the
2326  // definition in such a case.
2327  if (I->isAlignmentDependent())
2328  return false;
2329 
2330  if (I->isAlignas())
2331  OldAlignasAttr = I;
2332 
2333  unsigned Align = I->getAlignment(S.Context);
2334  if (Align > OldAlign) {
2335  OldAlign = Align;
2336  OldStrictestAlignAttr = I;
2337  }
2338  }
2339 
2340  // Look for alignas attributes on New.
2341  AlignedAttr *NewAlignasAttr = nullptr;
2342  unsigned NewAlign = 0;
2343  for (auto *I : New->specific_attrs<AlignedAttr>()) {
2344  if (I->isAlignmentDependent())
2345  return false;
2346 
2347  if (I->isAlignas())
2348  NewAlignasAttr = I;
2349 
2350  unsigned Align = I->getAlignment(S.Context);
2351  if (Align > NewAlign)
2352  NewAlign = Align;
2353  }
2354 
2355  if (OldAlignasAttr && NewAlignasAttr && OldAlign != NewAlign) {
2356  // Both declarations have 'alignas' attributes. We require them to match.
2357  // C++11 [dcl.align]p6 and C11 6.7.5/7 both come close to saying this, but
2358  // fall short. (If two declarations both have alignas, they must both match
2359  // every definition, and so must match each other if there is a definition.)
2360 
2361  // If either declaration only contains 'alignas(0)' specifiers, then it
2362  // specifies the natural alignment for the type.
2363  if (OldAlign == 0 || NewAlign == 0) {
2364  QualType Ty;
2365  if (ValueDecl *VD = dyn_cast<ValueDecl>(New))
2366  Ty = VD->getType();
2367  else
2368  Ty = S.Context.getTagDeclType(cast<TagDecl>(New));
2369 
2370  if (OldAlign == 0)
2371  OldAlign = S.Context.getTypeAlign(Ty);
2372  if (NewAlign == 0)
2373  NewAlign = S.Context.getTypeAlign(Ty);
2374  }
2375 
2376  if (OldAlign != NewAlign) {
2377  S.Diag(NewAlignasAttr->getLocation(), diag::err_alignas_mismatch)
2378  << (unsigned)S.Context.toCharUnitsFromBits(OldAlign).getQuantity()
2379  << (unsigned)S.Context.toCharUnitsFromBits(NewAlign).getQuantity();
2380  S.Diag(OldAlignasAttr->getLocation(), diag::note_previous_declaration);
2381  }
2382  }
2383 
2384  if (OldAlignasAttr && !NewAlignasAttr && isAttributeTargetADefinition(New)) {
2385  // C++11 [dcl.align]p6:
2386  // if any declaration of an entity has an alignment-specifier,
2387  // every defining declaration of that entity shall specify an
2388  // equivalent alignment.
2389  // C11 6.7.5/7:
2390  // If the definition of an object does not have an alignment
2391  // specifier, any other declaration of that object shall also
2392  // have no alignment specifier.
2393  S.Diag(New->getLocation(), diag::err_alignas_missing_on_definition)
2394  << OldAlignasAttr;
2395  S.Diag(OldAlignasAttr->getLocation(), diag::note_alignas_on_declaration)
2396  << OldAlignasAttr;
2397  }
2398 
2399  bool AnyAdded = false;
2400 
2401  // Ensure we have an attribute representing the strictest alignment.
2402  if (OldAlign > NewAlign) {
2403  AlignedAttr *Clone = OldStrictestAlignAttr->clone(S.Context);
2404  Clone->setInherited(true);
2405  New->addAttr(Clone);
2406  AnyAdded = true;
2407  }
2408 
2409  // Ensure we have an alignas attribute if the old declaration had one.
2410  if (OldAlignasAttr && !NewAlignasAttr &&
2411  !(AnyAdded && OldStrictestAlignAttr->isAlignas())) {
2412  AlignedAttr *Clone = OldAlignasAttr->clone(S.Context);
2413  Clone->setInherited(true);
2414  New->addAttr(Clone);
2415  AnyAdded = true;
2416  }
2417 
2418  return AnyAdded;
2419 }
2420 
2421 static bool mergeDeclAttribute(Sema &S, NamedDecl *D,
2422  const InheritableAttr *Attr,
2424  // This function copies an attribute Attr from a previous declaration to the
2425  // new declaration D if the new declaration doesn't itself have that attribute
2426  // yet or if that attribute allows duplicates.
2427  // If you're adding a new attribute that requires logic different from
2428  // "use explicit attribute on decl if present, else use attribute from
2429  // previous decl", for example if the attribute needs to be consistent
2430  // between redeclarations, you need to call a custom merge function here.
2431  InheritableAttr *NewAttr = nullptr;
2432  unsigned AttrSpellingListIndex = Attr->getSpellingListIndex();
2433  if (const auto *AA = dyn_cast<AvailabilityAttr>(Attr))
2434  NewAttr = S.mergeAvailabilityAttr(D, AA->getRange(), AA->getPlatform(),
2435  AA->isImplicit(), AA->getIntroduced(),
2436  AA->getDeprecated(),
2437  AA->getObsoleted(), AA->getUnavailable(),
2438  AA->getMessage(), AA->getStrict(),
2439  AA->getReplacement(), AMK,
2440  AttrSpellingListIndex);
2441  else if (const auto *VA = dyn_cast<VisibilityAttr>(Attr))
2442  NewAttr = S.mergeVisibilityAttr(D, VA->getRange(), VA->getVisibility(),
2443  AttrSpellingListIndex);
2444  else if (const auto *VA = dyn_cast<TypeVisibilityAttr>(Attr))
2445  NewAttr = S.mergeTypeVisibilityAttr(D, VA->getRange(), VA->getVisibility(),
2446  AttrSpellingListIndex);
2447  else if (const auto *ImportA = dyn_cast<DLLImportAttr>(Attr))
2448  NewAttr = S.mergeDLLImportAttr(D, ImportA->getRange(),
2449  AttrSpellingListIndex);
2450  else if (const auto *ExportA = dyn_cast<DLLExportAttr>(Attr))
2451  NewAttr = S.mergeDLLExportAttr(D, ExportA->getRange(),
2452  AttrSpellingListIndex);
2453  else if (const auto *FA = dyn_cast<FormatAttr>(Attr))
2454  NewAttr = S.mergeFormatAttr(D, FA->getRange(), FA->getType(),
2455  FA->getFormatIdx(), FA->getFirstArg(),
2456  AttrSpellingListIndex);
2457  else if (const auto *SA = dyn_cast<SectionAttr>(Attr))
2458  NewAttr = S.mergeSectionAttr(D, SA->getRange(), SA->getName(),
2459  AttrSpellingListIndex);
2460  else if (const auto *IA = dyn_cast<MSInheritanceAttr>(Attr))
2461  NewAttr = S.mergeMSInheritanceAttr(D, IA->getRange(), IA->getBestCase(),
2462  AttrSpellingListIndex,
2463  IA->getSemanticSpelling());
2464  else if (const auto *AA = dyn_cast<AlwaysInlineAttr>(Attr))
2465  NewAttr = S.mergeAlwaysInlineAttr(D, AA->getRange(),
2466  &S.Context.Idents.get(AA->getSpelling()),
2467  AttrSpellingListIndex);
2468  else if (S.getLangOpts().CUDA && isa<FunctionDecl>(D) &&
2469  (isa<CUDAHostAttr>(Attr) || isa<CUDADeviceAttr>(Attr) ||
2470  isa<CUDAGlobalAttr>(Attr))) {
2471  // CUDA target attributes are part of function signature for
2472  // overloading purposes and must not be merged.
2473  return false;
2474  } else if (const auto *MA = dyn_cast<MinSizeAttr>(Attr))
2475  NewAttr = S.mergeMinSizeAttr(D, MA->getRange(), AttrSpellingListIndex);
2476  else if (const auto *OA = dyn_cast<OptimizeNoneAttr>(Attr))
2477  NewAttr = S.mergeOptimizeNoneAttr(D, OA->getRange(), AttrSpellingListIndex);
2478  else if (const auto *InternalLinkageA = dyn_cast<InternalLinkageAttr>(Attr))
2479  NewAttr = S.mergeInternalLinkageAttr(
2480  D, InternalLinkageA->getRange(),
2481  &S.Context.Idents.get(InternalLinkageA->getSpelling()),
2482  AttrSpellingListIndex);
2483  else if (const auto *CommonA = dyn_cast<CommonAttr>(Attr))
2484  NewAttr = S.mergeCommonAttr(D, CommonA->getRange(),
2485  &S.Context.Idents.get(CommonA->getSpelling()),
2486  AttrSpellingListIndex);
2487  else if (isa<AlignedAttr>(Attr))
2488  // AlignedAttrs are handled separately, because we need to handle all
2489  // such attributes on a declaration at the same time.
2490  NewAttr = nullptr;
2491  else if ((isa<DeprecatedAttr>(Attr) || isa<UnavailableAttr>(Attr)) &&
2492  (AMK == Sema::AMK_Override ||
2494  NewAttr = nullptr;
2495  else if (const auto *UA = dyn_cast<UuidAttr>(Attr))
2496  NewAttr = S.mergeUuidAttr(D, UA->getRange(), AttrSpellingListIndex,
2497  UA->getGuid());
2498  else if (Attr->duplicatesAllowed() || !DeclHasAttr(D, Attr))
2499  NewAttr = cast<InheritableAttr>(Attr->clone(S.Context));
2500 
2501  if (NewAttr) {
2502  NewAttr->setInherited(true);
2503  D->addAttr(NewAttr);
2504  if (isa<MSInheritanceAttr>(NewAttr))
2505  S.Consumer.AssignInheritanceModel(cast<CXXRecordDecl>(D));
2506  return true;
2507  }
2508 
2509  return false;
2510 }
2511 
2512 static const NamedDecl *getDefinition(const Decl *D) {
2513  if (const TagDecl *TD = dyn_cast<TagDecl>(D))
2514  return TD->getDefinition();
2515  if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
2516  const VarDecl *Def = VD->getDefinition();
2517  if (Def)
2518  return Def;
2519  return VD->getActingDefinition();
2520  }
2521  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
2522  return FD->getDefinition();
2523  return nullptr;
2524 }
2525 
2526 static bool hasAttribute(const Decl *D, attr::Kind Kind) {
2527  for (const auto *Attribute : D->attrs())
2528  if (Attribute->getKind() == Kind)
2529  return true;
2530  return false;
2531 }
2532 
2533 /// checkNewAttributesAfterDef - If we already have a definition, check that
2534 /// there are no new attributes in this declaration.
2535 static void checkNewAttributesAfterDef(Sema &S, Decl *New, const Decl *Old) {
2536  if (!New->hasAttrs())
2537  return;
2538 
2539  const NamedDecl *Def = getDefinition(Old);
2540  if (!Def || Def == New)
2541  return;
2542 
2543  AttrVec &NewAttributes = New->getAttrs();
2544  for (unsigned I = 0, E = NewAttributes.size(); I != E;) {
2545  const Attr *NewAttribute = NewAttributes[I];
2546 
2547  if (isa<AliasAttr>(NewAttribute) || isa<IFuncAttr>(NewAttribute)) {
2548  if (FunctionDecl *FD = dyn_cast<FunctionDecl>(New)) {
2549  Sema::SkipBodyInfo SkipBody;
2550  S.CheckForFunctionRedefinition(FD, cast<FunctionDecl>(Def), &SkipBody);
2551 
2552  // If we're skipping this definition, drop the "alias" attribute.
2553  if (SkipBody.ShouldSkip) {
2554  NewAttributes.erase(NewAttributes.begin() + I);
2555  --E;
2556  continue;
2557  }
2558  } else {
2559  VarDecl *VD = cast<VarDecl>(New);
2560  unsigned Diag = cast<VarDecl>(Def)->isThisDeclarationADefinition() ==
2562  ? diag::err_alias_after_tentative
2563  : diag::err_redefinition;
2564  S.Diag(VD->getLocation(), Diag) << VD->getDeclName();
2565  if (Diag == diag::err_redefinition)
2566  S.notePreviousDefinition(Def, VD->getLocation());
2567  else
2568  S.Diag(Def->getLocation(), diag::note_previous_definition);
2569  VD->setInvalidDecl();
2570  }
2571  ++I;
2572  continue;
2573  }
2574 
2575  if (const VarDecl *VD = dyn_cast<VarDecl>(Def)) {
2576  // Tentative definitions are only interesting for the alias check above.
2577  if (VD->isThisDeclarationADefinition() != VarDecl::Definition) {
2578  ++I;
2579  continue;
2580  }
2581  }
2582 
2583  if (hasAttribute(Def, NewAttribute->getKind())) {
2584  ++I;
2585  continue; // regular attr merging will take care of validating this.
2586  }
2587 
2588  if (isa<C11NoReturnAttr>(NewAttribute)) {
2589  // C's _Noreturn is allowed to be added to a function after it is defined.
2590  ++I;
2591  continue;
2592  } else if (const AlignedAttr *AA = dyn_cast<AlignedAttr>(NewAttribute)) {
2593  if (AA->isAlignas()) {
2594  // C++11 [dcl.align]p6:
2595  // if any declaration of an entity has an alignment-specifier,
2596  // every defining declaration of that entity shall specify an
2597  // equivalent alignment.
2598  // C11 6.7.5/7:
2599  // If the definition of an object does not have an alignment
2600  // specifier, any other declaration of that object shall also
2601  // have no alignment specifier.
2602  S.Diag(Def->getLocation(), diag::err_alignas_missing_on_definition)
2603  << AA;
2604  S.Diag(NewAttribute->getLocation(), diag::note_alignas_on_declaration)
2605  << AA;
2606  NewAttributes.erase(NewAttributes.begin() + I);
2607  --E;
2608  continue;
2609  }
2610  }
2611 
2612  S.Diag(NewAttribute->getLocation(),
2613  diag::warn_attribute_precede_definition);
2614  S.Diag(Def->getLocation(), diag::note_previous_definition);
2615  NewAttributes.erase(NewAttributes.begin() + I);
2616  --E;
2617  }
2618 }
2619 
2620 /// mergeDeclAttributes - Copy attributes from the Old decl to the New one.
2622  AvailabilityMergeKind AMK) {
2623  if (UsedAttr *OldAttr = Old->getMostRecentDecl()->getAttr<UsedAttr>()) {
2624  UsedAttr *NewAttr = OldAttr->clone(Context);
2625  NewAttr->setInherited(true);
2626  New->addAttr(NewAttr);
2627  }
2628 
2629  if (!Old->hasAttrs() && !New->hasAttrs())
2630  return;
2631 
2632  // Attributes declared post-definition are currently ignored.
2633  checkNewAttributesAfterDef(*this, New, Old);
2634 
2635  if (AsmLabelAttr *NewA = New->getAttr<AsmLabelAttr>()) {
2636  if (AsmLabelAttr *OldA = Old->getAttr<AsmLabelAttr>()) {
2637  if (OldA->getLabel() != NewA->getLabel()) {
2638  // This redeclaration changes __asm__ label.
2639  Diag(New->getLocation(), diag::err_different_asm_label);
2640  Diag(OldA->getLocation(), diag::note_previous_declaration);
2641  }
2642  } else if (Old->isUsed()) {
2643  // This redeclaration adds an __asm__ label to a declaration that has
2644  // already been ODR-used.
2645  Diag(New->getLocation(), diag::err_late_asm_label_name)
2646  << isa<FunctionDecl>(Old) << New->getAttr<AsmLabelAttr>()->getRange();
2647  }
2648  }
2649 
2650  // Re-declaration cannot add abi_tag's.
2651  if (const auto *NewAbiTagAttr = New->getAttr<AbiTagAttr>()) {
2652  if (const auto *OldAbiTagAttr = Old->getAttr<AbiTagAttr>()) {
2653  for (const auto &NewTag : NewAbiTagAttr->tags()) {
2654  if (std::find(OldAbiTagAttr->tags_begin(), OldAbiTagAttr->tags_end(),
2655  NewTag) == OldAbiTagAttr->tags_end()) {
2656  Diag(NewAbiTagAttr->getLocation(),
2657  diag::err_new_abi_tag_on_redeclaration)
2658  << NewTag;
2659  Diag(OldAbiTagAttr->getLocation(), diag::note_previous_declaration);
2660  }
2661  }
2662  } else {
2663  Diag(NewAbiTagAttr->getLocation(), diag::err_abi_tag_on_redeclaration);
2664  Diag(Old->getLocation(), diag::note_previous_declaration);
2665  }
2666  }
2667 
2668  // This redeclaration adds a section attribute.
2669  if (New->hasAttr<SectionAttr>() && !Old->hasAttr<SectionAttr>()) {
2670  if (auto *VD = dyn_cast<VarDecl>(New)) {
2671  if (VD->isThisDeclarationADefinition() == VarDecl::DeclarationOnly) {
2672  Diag(New->getLocation(), diag::warn_attribute_section_on_redeclaration);
2673  Diag(Old->getLocation(), diag::note_previous_declaration);
2674  }
2675  }
2676  }
2677 
2678  if (!Old->hasAttrs())
2679  return;
2680 
2681  bool foundAny = New->hasAttrs();
2682 
2683  // Ensure that any moving of objects within the allocated map is done before
2684  // we process them.
2685  if (!foundAny) New->setAttrs(AttrVec());
2686 
2687  for (auto *I : Old->specific_attrs<InheritableAttr>()) {
2688  // Ignore deprecated/unavailable/availability attributes if requested.
2689  AvailabilityMergeKind LocalAMK = AMK_None;
2690  if (isa<DeprecatedAttr>(I) ||
2691  isa<UnavailableAttr>(I) ||
2692  isa<AvailabilityAttr>(I)) {
2693  switch (AMK) {
2694  case AMK_None:
2695  continue;
2696 
2697  case AMK_Redeclaration:
2698  case AMK_Override:
2699  case AMK_ProtocolImplementation:
2700  LocalAMK = AMK;
2701  break;
2702  }
2703  }
2704 
2705  // Already handled.
2706  if (isa<UsedAttr>(I))
2707  continue;
2708 
2709  if (mergeDeclAttribute(*this, New, I, LocalAMK))
2710  foundAny = true;
2711  }
2712 
2713  if (mergeAlignedAttrs(*this, New, Old))
2714  foundAny = true;
2715 
2716  if (!foundAny) New->dropAttrs();
2717 }
2718 
2719 /// mergeParamDeclAttributes - Copy attributes from the old parameter
2720 /// to the new one.
2722  const ParmVarDecl *oldDecl,
2723  Sema &S) {
2724  // C++11 [dcl.attr.depend]p2:
2725  // The first declaration of a function shall specify the
2726  // carries_dependency attribute for its declarator-id if any declaration
2727  // of the function specifies the carries_dependency attribute.
2728  const CarriesDependencyAttr *CDA = newDecl->getAttr<CarriesDependencyAttr>();
2729  if (CDA && !oldDecl->hasAttr<CarriesDependencyAttr>()) {
2730  S.Diag(CDA->getLocation(),
2731  diag::err_carries_dependency_missing_on_first_decl) << 1/*Param*/;
2732  // Find the first declaration of the parameter.
2733  // FIXME: Should we build redeclaration chains for function parameters?
2734  const FunctionDecl *FirstFD =
2735  cast<FunctionDecl>(oldDecl->getDeclContext())->getFirstDecl();
2736  const ParmVarDecl *FirstVD =
2737  FirstFD->getParamDecl(oldDecl->getFunctionScopeIndex());
2738  S.Diag(FirstVD->getLocation(),
2739  diag::note_carries_dependency_missing_first_decl) << 1/*Param*/;
2740  }
2741 
2742  if (!oldDecl->hasAttrs())
2743  return;
2744 
2745  bool foundAny = newDecl->hasAttrs();
2746 
2747  // Ensure that any moving of objects within the allocated map is
2748  // done before we process them.
2749  if (!foundAny) newDecl->setAttrs(AttrVec());
2750 
2751  for (const auto *I : oldDecl->specific_attrs<InheritableParamAttr>()) {
2752  if (!DeclHasAttr(newDecl, I)) {
2753  InheritableAttr *newAttr =
2754  cast<InheritableParamAttr>(I->clone(S.Context));
2755  newAttr->setInherited(true);
2756  newDecl->addAttr(newAttr);
2757  foundAny = true;
2758  }
2759  }
2760 
2761  if (!foundAny) newDecl->dropAttrs();
2762 }
2763 
2764 static void mergeParamDeclTypes(ParmVarDecl *NewParam,
2765  const ParmVarDecl *OldParam,
2766  Sema &S) {
2767  if (auto Oldnullability = OldParam->getType()->getNullability(S.Context)) {
2768  if (auto Newnullability = NewParam->getType()->getNullability(S.Context)) {
2769  if (*Oldnullability != *Newnullability) {
2770  S.Diag(NewParam->getLocation(), diag::warn_mismatched_nullability_attr)
2772  *Newnullability,
2774  != 0))
2776  *Oldnullability,
2778  != 0));
2779  S.Diag(OldParam->getLocation(), diag::note_previous_declaration);
2780  }
2781  } else {
2782  QualType NewT = NewParam->getType();
2783  NewT = S.Context.getAttributedType(
2784  AttributedType::getNullabilityAttrKind(*Oldnullability),
2785  NewT, NewT);
2786  NewParam->setType(NewT);
2787  }
2788  }
2789 }
2790 
2791 namespace {
2792 
2793 /// Used in MergeFunctionDecl to keep track of function parameters in
2794 /// C.
2795 struct GNUCompatibleParamWarning {
2796  ParmVarDecl *OldParm;
2797  ParmVarDecl *NewParm;
2798  QualType PromotedType;
2799 };
2800 
2801 } // end anonymous namespace
2802 
2803 /// getSpecialMember - get the special member enum for a method.
2805  if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) {
2806  if (Ctor->isDefaultConstructor())
2808 
2809  if (Ctor->isCopyConstructor())
2810  return Sema::CXXCopyConstructor;
2811 
2812  if (Ctor->isMoveConstructor())
2813  return Sema::CXXMoveConstructor;
2814  } else if (isa<CXXDestructorDecl>(MD)) {
2815  return Sema::CXXDestructor;
2816  } else if (MD->isCopyAssignmentOperator()) {
2817  return Sema::CXXCopyAssignment;
2818  } else if (MD->isMoveAssignmentOperator()) {
2819  return Sema::CXXMoveAssignment;
2820  }
2821 
2822  return Sema::CXXInvalid;
2823 }
2824 
2825 // Determine whether the previous declaration was a definition, implicit
2826 // declaration, or a declaration.
2827 template <typename T>
2828 static std::pair<diag::kind, SourceLocation>
2829 getNoteDiagForInvalidRedeclaration(const T *Old, const T *New) {
2830  diag::kind PrevDiag;
2831  SourceLocation OldLocation = Old->getLocation();
2832  if (Old->isThisDeclarationADefinition())
2833  PrevDiag = diag::note_previous_definition;
2834  else if (Old->isImplicit()) {
2835  PrevDiag = diag::note_previous_implicit_declaration;
2836  if (OldLocation.isInvalid())
2837  OldLocation = New->getLocation();
2838  } else
2839  PrevDiag = diag::note_previous_declaration;
2840  return std::make_pair(PrevDiag, OldLocation);
2841 }
2842 
2843 /// canRedefineFunction - checks if a function can be redefined. Currently,
2844 /// only extern inline functions can be redefined, and even then only in
2845 /// GNU89 mode.
2846 static bool canRedefineFunction(const FunctionDecl *FD,
2847  const LangOptions& LangOpts) {
2848  return ((FD->hasAttr<GNUInlineAttr>() || LangOpts.GNUInline) &&
2849  !LangOpts.CPlusPlus &&
2850  FD->isInlineSpecified() &&
2851  FD->getStorageClass() == SC_Extern);
2852 }
2853 
2855  const AttributedType *AT = T->getAs<AttributedType>();
2856  while (AT && !AT->isCallingConv())
2857  AT = AT->getModifiedType()->getAs<AttributedType>();
2858  return AT;
2859 }
2860 
2861 template <typename T>
2862 static bool haveIncompatibleLanguageLinkages(const T *Old, const T *New) {
2863  const DeclContext *DC = Old->getDeclContext();
2864  if (DC->isRecord())
2865  return false;
2866 
2867  LanguageLinkage OldLinkage = Old->getLanguageLinkage();
2868  if (OldLinkage == CXXLanguageLinkage && New->isInExternCContext())
2869  return true;
2870  if (OldLinkage == CLanguageLinkage && New->isInExternCXXContext())
2871  return true;
2872  return false;
2873 }
2874 
2875 template<typename T> static bool isExternC(T *D) { return D->isExternC(); }
2876 static bool isExternC(VarTemplateDecl *) { return false; }
2877 
2878 /// \brief Check whether a redeclaration of an entity introduced by a
2879 /// using-declaration is valid, given that we know it's not an overload
2880 /// (nor a hidden tag declaration).
2881 template<typename ExpectedDecl>
2883  ExpectedDecl *New) {
2884  // C++11 [basic.scope.declarative]p4:
2885  // Given a set of declarations in a single declarative region, each of
2886  // which specifies the same unqualified name,
2887  // -- they shall all refer to the same entity, or all refer to functions
2888  // and function templates; or
2889  // -- exactly one declaration shall declare a class name or enumeration
2890  // name that is not a typedef name and the other declarations shall all
2891  // refer to the same variable or enumerator, or all refer to functions
2892  // and function templates; in this case the class name or enumeration
2893  // name is hidden (3.3.10).
2894 
2895  // C++11 [namespace.udecl]p14:
2896  // If a function declaration in namespace scope or block scope has the
2897  // same name and the same parameter-type-list as a function introduced
2898  // by a using-declaration, and the declarations do not declare the same
2899  // function, the program is ill-formed.
2900 
2901  auto *Old = dyn_cast<ExpectedDecl>(OldS->getTargetDecl());
2902  if (Old &&
2903  !Old->getDeclContext()->getRedeclContext()->Equals(
2904  New->getDeclContext()->getRedeclContext()) &&
2905  !(isExternC(Old) && isExternC(New)))
2906  Old = nullptr;
2907 
2908  if (!Old) {
2909  S.Diag(New->getLocation(), diag::err_using_decl_conflict_reverse);
2910  S.Diag(OldS->getTargetDecl()->getLocation(), diag::note_using_decl_target);
2911  S.Diag(OldS->getUsingDecl()->getLocation(), diag::note_using_decl) << 0;
2912  return true;
2913  }
2914  return false;
2915 }
2916 
2918  const FunctionDecl *B) {
2919  assert(A->getNumParams() == B->getNumParams());
2920 
2921  auto AttrEq = [](const ParmVarDecl *A, const ParmVarDecl *B) {
2922  const auto *AttrA = A->getAttr<PassObjectSizeAttr>();
2923  const auto *AttrB = B->getAttr<PassObjectSizeAttr>();
2924  if (AttrA == AttrB)
2925  return true;
2926  return AttrA && AttrB && AttrA->getType() == AttrB->getType();
2927  };
2928 
2929  return std::equal(A->param_begin(), A->param_end(), B->param_begin(), AttrEq);
2930 }
2931 
2932 /// MergeFunctionDecl - We just parsed a function 'New' from
2933 /// declarator D which has the same name and scope as a previous
2934 /// declaration 'Old'. Figure out how to resolve this situation,
2935 /// merging decls or emitting diagnostics as appropriate.
2936 ///
2937 /// In C++, New and Old must be declarations that are not
2938 /// overloaded. Use IsOverload to determine whether New and Old are
2939 /// overloaded, and to select the Old declaration that New should be
2940 /// merged with.
2941 ///
2942 /// Returns true if there was an error, false otherwise.
2944  Scope *S, bool MergeTypeWithOld) {
2945  // Verify the old decl was also a function.
2946  FunctionDecl *Old = OldD->getAsFunction();
2947  if (!Old) {
2948  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(OldD)) {
2949  if (New->getFriendObjectKind()) {
2950  Diag(New->getLocation(), diag::err_using_decl_friend);
2951  Diag(Shadow->getTargetDecl()->getLocation(),
2952  diag::note_using_decl_target);
2953  Diag(Shadow->getUsingDecl()->getLocation(),
2954  diag::note_using_decl) << 0;
2955  return true;
2956  }
2957 
2958  // Check whether the two declarations might declare the same function.
2959  if (checkUsingShadowRedecl<FunctionDecl>(*this, Shadow, New))
2960  return true;
2961  OldD = Old = cast<FunctionDecl>(Shadow->getTargetDecl());
2962  } else {
2963  Diag(New->getLocation(), diag::err_redefinition_different_kind)
2964  << New->getDeclName();
2965  notePreviousDefinition(OldD, New->getLocation());
2966  return true;
2967  }
2968  }
2969 
2970  // If the old declaration is invalid, just give up here.
2971  if (Old->isInvalidDecl())
2972  return true;
2973 
2974  diag::kind PrevDiag;
2975  SourceLocation OldLocation;
2976  std::tie(PrevDiag, OldLocation) =
2978 
2979  // Don't complain about this if we're in GNU89 mode and the old function
2980  // is an extern inline function.
2981  // Don't complain about specializations. They are not supposed to have
2982  // storage classes.
2983  if (!isa<CXXMethodDecl>(New) && !isa<CXXMethodDecl>(Old) &&
2984  New->getStorageClass() == SC_Static &&
2985  Old->hasExternalFormalLinkage() &&
2987  !canRedefineFunction(Old, getLangOpts())) {
2988  if (getLangOpts().MicrosoftExt) {
2989  Diag(New->getLocation(), diag::ext_static_non_static) << New;
2990  Diag(OldLocation, PrevDiag);
2991  } else {
2992  Diag(New->getLocation(), diag::err_static_non_static) << New;
2993  Diag(OldLocation, PrevDiag);
2994  return true;
2995  }
2996  }
2997 
2998  if (New->hasAttr<InternalLinkageAttr>() &&
2999  !Old->hasAttr<InternalLinkageAttr>()) {
3000  Diag(New->getLocation(), diag::err_internal_linkage_redeclaration)
3001  << New->getDeclName();
3002  notePreviousDefinition(Old, New->getLocation());
3003  New->dropAttr<InternalLinkageAttr>();
3004  }
3005 
3006  if (CheckRedeclarationModuleOwnership(New, Old))
3007  return true;
3008 
3009  if (!getLangOpts().CPlusPlus) {
3010  bool OldOvl = Old->hasAttr<OverloadableAttr>();
3011  if (OldOvl != New->hasAttr<OverloadableAttr>() && !Old->isImplicit()) {
3012  Diag(New->getLocation(), diag::err_attribute_overloadable_mismatch)
3013  << New << OldOvl;
3014 
3015  // Try our best to find a decl that actually has the overloadable
3016  // attribute for the note. In most cases (e.g. programs with only one
3017  // broken declaration/definition), this won't matter.
3018  //
3019  // FIXME: We could do this if we juggled some extra state in
3020  // OverloadableAttr, rather than just removing it.
3021  const Decl *DiagOld = Old;
3022  if (OldOvl) {
3023  auto OldIter = llvm::find_if(Old->redecls(), [](const Decl *D) {
3024  const auto *A = D->getAttr<OverloadableAttr>();
3025  return A && !A->isImplicit();
3026  });
3027  // If we've implicitly added *all* of the overloadable attrs to this
3028  // chain, emitting a "previous redecl" note is pointless.
3029  DiagOld = OldIter == Old->redecls_end() ? nullptr : *OldIter;
3030  }
3031 
3032  if (DiagOld)
3033  Diag(DiagOld->getLocation(),
3034  diag::note_attribute_overloadable_prev_overload)
3035  << OldOvl;
3036 
3037  if (OldOvl)
3038  New->addAttr(OverloadableAttr::CreateImplicit(Context));
3039  else
3040  New->dropAttr<OverloadableAttr>();
3041  }
3042  }
3043 
3044  // If a function is first declared with a calling convention, but is later
3045  // declared or defined without one, all following decls assume the calling
3046  // convention of the first.
3047  //
3048  // It's OK if a function is first declared without a calling convention,
3049  // but is later declared or defined with the default calling convention.
3050  //
3051  // To test if either decl has an explicit calling convention, we look for
3052  // AttributedType sugar nodes on the type as written. If they are missing or
3053  // were canonicalized away, we assume the calling convention was implicit.
3054  //
3055  // Note also that we DO NOT return at this point, because we still have
3056  // other tests to run.
3057  QualType OldQType = Context.getCanonicalType(Old->getType());
3058  QualType NewQType = Context.getCanonicalType(New->getType());
3059  const FunctionType *OldType = cast<FunctionType>(OldQType);
3060  const FunctionType *NewType = cast<FunctionType>(NewQType);
3061  FunctionType::ExtInfo OldTypeInfo = OldType->getExtInfo();
3062  FunctionType::ExtInfo NewTypeInfo = NewType->getExtInfo();
3063  bool RequiresAdjustment = false;
3064 
3065  if (OldTypeInfo.getCC() != NewTypeInfo.getCC()) {
3066  FunctionDecl *First = Old->getFirstDecl();
3067  const FunctionType *FT =
3069  FunctionType::ExtInfo FI = FT->getExtInfo();
3070  bool NewCCExplicit = getCallingConvAttributedType(New->getType());
3071  if (!NewCCExplicit) {
3072  // Inherit the CC from the previous declaration if it was specified
3073  // there but not here.
3074  NewTypeInfo = NewTypeInfo.withCallingConv(OldTypeInfo.getCC());
3075  RequiresAdjustment = true;
3076  } else {
3077  // Calling conventions aren't compatible, so complain.
3078  bool FirstCCExplicit = getCallingConvAttributedType(First->getType());
3079  Diag(New->getLocation(), diag::err_cconv_change)
3080  << FunctionType::getNameForCallConv(NewTypeInfo.getCC())
3081  << !FirstCCExplicit
3082  << (!FirstCCExplicit ? "" :
3083  FunctionType::getNameForCallConv(FI.getCC()));
3084 
3085  // Put the note on the first decl, since it is the one that matters.
3086  Diag(First->getLocation(), diag::note_previous_declaration);
3087  return true;
3088  }
3089  }
3090 
3091  // FIXME: diagnose the other way around?
3092  if (OldTypeInfo.getNoReturn() && !NewTypeInfo.getNoReturn()) {
3093  NewTypeInfo = NewTypeInfo.withNoReturn(true);
3094  RequiresAdjustment = true;
3095  }
3096 
3097  // Merge regparm attribute.
3098  if (OldTypeInfo.getHasRegParm() != NewTypeInfo.getHasRegParm() ||
3099  OldTypeInfo.getRegParm() != NewTypeInfo.getRegParm()) {
3100  if (NewTypeInfo.getHasRegParm()) {
3101  Diag(New->getLocation(), diag::err_regparm_mismatch)
3102  << NewType->getRegParmType()
3103  << OldType->getRegParmType();
3104  Diag(OldLocation, diag::note_previous_declaration);
3105  return true;
3106  }
3107 
3108  NewTypeInfo = NewTypeInfo.withRegParm(OldTypeInfo.getRegParm());
3109  RequiresAdjustment = true;
3110  }
3111 
3112  // Merge ns_returns_retained attribute.
3113  if (OldTypeInfo.getProducesResult() != NewTypeInfo.getProducesResult()) {
3114  if (NewTypeInfo.getProducesResult()) {
3115  Diag(New->getLocation(), diag::err_function_attribute_mismatch)
3116  << "'ns_returns_retained'";
3117  Diag(OldLocation, diag::note_previous_declaration);
3118  return true;
3119  }
3120 
3121  NewTypeInfo = NewTypeInfo.withProducesResult(true);
3122  RequiresAdjustment = true;
3123  }
3124 
3125  if (OldTypeInfo.getNoCallerSavedRegs() !=
3126  NewTypeInfo.getNoCallerSavedRegs()) {
3127  if (NewTypeInfo.getNoCallerSavedRegs()) {
3128  AnyX86NoCallerSavedRegistersAttr *Attr =
3129  New->getAttr<AnyX86NoCallerSavedRegistersAttr>();
3130  Diag(New->getLocation(), diag::err_function_attribute_mismatch) << Attr;
3131  Diag(OldLocation, diag::note_previous_declaration);
3132  return true;
3133  }
3134 
3135  NewTypeInfo = NewTypeInfo.withNoCallerSavedRegs(true);
3136  RequiresAdjustment = true;
3137  }
3138 
3139  if (RequiresAdjustment) {
3140  const FunctionType *AdjustedType = New->getType()->getAs<FunctionType>();
3141  AdjustedType = Context.adjustFunctionType(AdjustedType, NewTypeInfo);
3142  New->setType(QualType(AdjustedType, 0));
3143  NewQType = Context.getCanonicalType(New->getType());
3144  NewType = cast<FunctionType>(NewQType);
3145  }
3146 
3147  // If this redeclaration makes the function inline, we may need to add it to
3148  // UndefinedButUsed.
3149  if (!Old->isInlined() && New->isInlined() &&
3150  !New->hasAttr<GNUInlineAttr>() &&
3151  !getLangOpts().GNUInline &&
3152  Old->isUsed(false) &&
3153  !Old->isDefined() && !New->isThisDeclarationADefinition())
3154  UndefinedButUsed.insert(std::make_pair(Old->getCanonicalDecl(),
3155  SourceLocation()));
3156 
3157  // If this redeclaration makes it newly gnu_inline, we don't want to warn
3158  // about it.
3159  if (New->hasAttr<GNUInlineAttr>() &&
3160  Old->isInlined() && !Old->hasAttr<GNUInlineAttr>()) {
3161  UndefinedButUsed.erase(Old->getCanonicalDecl());
3162  }
3163 
3164  // If pass_object_size params don't match up perfectly, this isn't a valid
3165  // redeclaration.
3166  if (Old->getNumParams() > 0 && Old->getNumParams() == New->getNumParams() &&
3167  !hasIdenticalPassObjectSizeAttrs(Old, New)) {
3168  Diag(New->getLocation(), diag::err_different_pass_object_size_params)
3169  << New->getDeclName();
3170  Diag(OldLocation, PrevDiag) << Old << Old->getType();
3171  return true;
3172  }
3173 
3174  if (getLangOpts().CPlusPlus) {
3175  // C++1z [over.load]p2
3176  // Certain function declarations cannot be overloaded:
3177  // -- Function declarations that differ only in the return type,
3178  // the exception specification, or both cannot be overloaded.
3179 
3180  // Check the exception specifications match. This may recompute the type of
3181  // both Old and New if it resolved exception specifications, so grab the
3182  // types again after this. Because this updates the type, we do this before
3183  // any of the other checks below, which may update the "de facto" NewQType
3184  // but do not necessarily update the type of New.
3185  if (CheckEquivalentExceptionSpec(Old, New))
3186  return true;
3187  OldQType = Context.getCanonicalType(Old->getType());
3188  NewQType = Context.getCanonicalType(New->getType());
3189 
3190  // Go back to the type source info to compare the declared return types,
3191  // per C++1y [dcl.type.auto]p13:
3192  // Redeclarations or specializations of a function or function template
3193  // with a declared return type that uses a placeholder type shall also
3194  // use that placeholder, not a deduced type.
3195  QualType OldDeclaredReturnType =
3196  (Old->getTypeSourceInfo()
3198  : OldType)->getReturnType();
3199  QualType NewDeclaredReturnType =
3200  (New->getTypeSourceInfo()
3202  : NewType)->getReturnType();
3203  if (!Context.hasSameType(OldDeclaredReturnType, NewDeclaredReturnType) &&
3204  !((NewQType->isDependentType() || OldQType->isDependentType()) &&
3205  New->isLocalExternDecl())) {
3206  QualType ResQT;
3207  if (NewDeclaredReturnType->isObjCObjectPointerType() &&
3208  OldDeclaredReturnType->isObjCObjectPointerType())
3209  ResQT = Context.mergeObjCGCQualifiers(NewQType, OldQType);
3210  if (ResQT.isNull()) {
3211  if (New->isCXXClassMember() && New->isOutOfLine())
3212  Diag(New->getLocation(), diag::err_member_def_does_not_match_ret_type)
3213  << New << New->getReturnTypeSourceRange();
3214  else
3215  Diag(New->getLocation(), diag::err_ovl_diff_return_type)
3216  << New->getReturnTypeSourceRange();
3217  Diag(OldLocation, PrevDiag) << Old << Old->getType()
3218  << Old->getReturnTypeSourceRange();
3219  return true;
3220  }
3221  else
3222  NewQType = ResQT;
3223  }
3224 
3225  QualType OldReturnType = OldType->getReturnType();
3226  QualType NewReturnType = cast<FunctionType>(NewQType)->getReturnType();
3227  if (OldReturnType != NewReturnType) {
3228  // If this function has a deduced return type and has already been
3229  // defined, copy the deduced value from the old declaration.
3230  AutoType *OldAT = Old->getReturnType()->getContainedAutoType();
3231  if (OldAT && OldAT->isDeduced()) {
3232  New->setType(
3233  SubstAutoType(New->getType(),
3234  OldAT->isDependentType() ? Context.DependentTy
3235  : OldAT->getDeducedType()));
3236  NewQType = Context.getCanonicalType(
3237  SubstAutoType(NewQType,
3238  OldAT->isDependentType() ? Context.DependentTy
3239  : OldAT->getDeducedType()));
3240  }
3241  }
3242 
3243  const CXXMethodDecl *OldMethod = dyn_cast<CXXMethodDecl>(Old);
3244  CXXMethodDecl *NewMethod = dyn_cast<CXXMethodDecl>(New);
3245  if (OldMethod && NewMethod) {
3246  // Preserve triviality.
3247  NewMethod->setTrivial(OldMethod->isTrivial());
3248 
3249  // MSVC allows explicit template specialization at class scope:
3250  // 2 CXXMethodDecls referring to the same function will be injected.
3251  // We don't want a redeclaration error.
3252  bool IsClassScopeExplicitSpecialization =
3253  OldMethod->isFunctionTemplateSpecialization() &&
3254  NewMethod->isFunctionTemplateSpecialization();
3255  bool isFriend = NewMethod->getFriendObjectKind();
3256 
3257  if (!isFriend && NewMethod->getLexicalDeclContext()->isRecord() &&
3258  !IsClassScopeExplicitSpecialization) {
3259  // -- Member function declarations with the same name and the
3260  // same parameter types cannot be overloaded if any of them
3261  // is a static member function declaration.
3262  if (OldMethod->isStatic() != NewMethod->isStatic()) {
3263  Diag(New->getLocation(), diag::err_ovl_static_nonstatic_member);
3264  Diag(OldLocation, PrevDiag) << Old << Old->getType();
3265  return true;
3266  }
3267 
3268  // C++ [class.mem]p1:
3269  // [...] A member shall not be declared twice in the
3270  // member-specification, except that a nested class or member
3271  // class template can be declared and then later defined.
3272  if (!inTemplateInstantiation()) {
3273  unsigned NewDiag;
3274  if (isa<CXXConstructorDecl>(OldMethod))
3275  NewDiag = diag::err_constructor_redeclared;
3276  else if (isa<CXXDestructorDecl>(NewMethod))
3277  NewDiag = diag::err_destructor_redeclared;
3278  else if (isa<CXXConversionDecl>(NewMethod))
3279  NewDiag = diag::err_conv_function_redeclared;
3280  else
3281  NewDiag = diag::err_member_redeclared;
3282 
3283  Diag(New->getLocation(), NewDiag);
3284  } else {
3285  Diag(New->getLocation(), diag::err_member_redeclared_in_instantiation)
3286  << New << New->getType();
3287  }
3288  Diag(OldLocation, PrevDiag) << Old << Old->getType();
3289  return true;
3290 
3291  // Complain if this is an explicit declaration of a special
3292  // member that was initially declared implicitly.
3293  //
3294  // As an exception, it's okay to befriend such methods in order
3295  // to permit the implicit constructor/destructor/operator calls.
3296  } else if (OldMethod->isImplicit()) {
3297  if (isFriend) {
3298  NewMethod->setImplicit();
3299  } else {
3300  Diag(NewMethod->getLocation(),
3301  diag::err_definition_of_implicitly_declared_member)
3302  << New << getSpecialMember(OldMethod);
3303  return true;
3304  }
3305  } else if (OldMethod->getFirstDecl()->isExplicitlyDefaulted() && !isFriend) {
3306  Diag(NewMethod->getLocation(),
3307  diag::err_definition_of_explicitly_defaulted_member)
3308  << getSpecialMember(OldMethod);
3309  return true;
3310  }
3311  }
3312 
3313  // C++11 [dcl.attr.noreturn]p1:
3314  // The first declaration of a function shall specify the noreturn
3315  // attribute if any declaration of that function specifies the noreturn
3316  // attribute.
3317  const CXX11NoReturnAttr *NRA = New->getAttr<CXX11NoReturnAttr>();
3318  if (NRA && !Old->hasAttr<CXX11NoReturnAttr>()) {
3319  Diag(NRA->getLocation(), diag::err_noreturn_missing_on_first_decl);
3320  Diag(Old->getFirstDecl()->getLocation(),
3321  diag::note_noreturn_missing_first_decl);
3322  }
3323 
3324  // C++11 [dcl.attr.depend]p2:
3325  // The first declaration of a function shall specify the
3326  // carries_dependency attribute for its declarator-id if any declaration
3327  // of the function specifies the carries_dependency attribute.
3328  const CarriesDependencyAttr *CDA = New->getAttr<CarriesDependencyAttr>();
3329  if (CDA && !Old->hasAttr<CarriesDependencyAttr>()) {
3330  Diag(CDA->getLocation(),
3331  diag::err_carries_dependency_missing_on_first_decl) << 0/*Function*/;
3332  Diag(Old->getFirstDecl()->getLocation(),
3333  diag::note_carries_dependency_missing_first_decl) << 0/*Function*/;
3334  }
3335 
3336  // (C++98 8.3.5p3):
3337  // All declarations for a function shall agree exactly in both the
3338  // return type and the parameter-type-list.
3339  // We also want to respect all the extended bits except noreturn.
3340 
3341  // noreturn should now match unless the old type info didn't have it.
3342  QualType OldQTypeForComparison = OldQType;
3343  if (!OldTypeInfo.getNoReturn() && NewTypeInfo.getNoReturn()) {
3344  auto *OldType = OldQType->castAs<FunctionProtoType>();
3345  const FunctionType *OldTypeForComparison
3346  = Context.adjustFunctionType(OldType, OldTypeInfo.withNoReturn(true));
3347  OldQTypeForComparison = QualType(OldTypeForComparison, 0);
3348  assert(OldQTypeForComparison.isCanonical());
3349  }
3350 
3351  if (haveIncompatibleLanguageLinkages(Old, New)) {
3352  // As a special case, retain the language linkage from previous
3353  // declarations of a friend function as an extension.
3354  //
3355  // This liberal interpretation of C++ [class.friend]p3 matches GCC/MSVC
3356  // and is useful because there's otherwise no way to specify language
3357  // linkage within class scope.
3358  //
3359  // Check cautiously as the friend object kind isn't yet complete.
3360  if (New->getFriendObjectKind() != Decl::FOK_None) {
3361  Diag(New->getLocation(), diag::ext_retained_language_linkage) << New;
3362  Diag(OldLocation, PrevDiag);
3363  } else {
3364  Diag(New->getLocation(), diag::err_different_language_linkage) << New;
3365  Diag(OldLocation, PrevDiag);
3366  return true;
3367  }
3368  }
3369 
3370  if (OldQTypeForComparison == NewQType)
3371  return MergeCompatibleFunctionDecls(New, Old, S, MergeTypeWithOld);
3372 
3373  if ((NewQType->isDependentType() || OldQType->isDependentType()) &&
3374  New->isLocalExternDecl()) {
3375  // It's OK if we couldn't merge types for a local function declaraton
3376  // if either the old or new type is dependent. We'll merge the types
3377  // when we instantiate the function.
3378  return false;
3379  }
3380 
3381  // Fall through for conflicting redeclarations and redefinitions.
3382  }
3383 
3384  // C: Function types need to be compatible, not identical. This handles
3385  // duplicate function decls like "void f(int); void f(enum X);" properly.
3386  if (!getLangOpts().CPlusPlus &&
3387  Context.typesAreCompatible(OldQType, NewQType)) {
3388  const FunctionType *OldFuncType = OldQType->getAs<FunctionType>();
3389  const FunctionType *NewFuncType = NewQType->getAs<FunctionType>();
3390  const FunctionProtoType *OldProto = nullptr;
3391  if (MergeTypeWithOld && isa<FunctionNoProtoType>(NewFuncType) &&
3392  (OldProto = dyn_cast<FunctionProtoType>(OldFuncType))) {
3393  // The old declaration provided a function prototype, but the
3394  // new declaration does not. Merge in the prototype.
3395  assert(!OldProto->hasExceptionSpec() && "Exception spec in C");
3396  SmallVector<QualType, 16> ParamTypes(OldProto->param_types());
3397  NewQType =
3398  Context.getFunctionType(NewFuncType->getReturnType(), ParamTypes,
3399  OldProto->getExtProtoInfo());
3400  New->setType(NewQType);
3401  New->setHasInheritedPrototype();
3402 
3403  // Synthesize parameters with the same types.
3405  for (const auto &ParamType : OldProto->param_types()) {
3406  ParmVarDecl *Param = ParmVarDecl::Create(Context, New, SourceLocation(),
3407  SourceLocation(), nullptr,
3408  ParamType, /*TInfo=*/nullptr,
3409  SC_None, nullptr);
3410  Param->setScopeInfo(0, Params.size());
3411  Param->setImplicit();
3412  Params.push_back(Param);
3413  }
3414 
3415  New->setParams(Params);
3416  }
3417 
3418  return MergeCompatibleFunctionDecls(New, Old, S, MergeTypeWithOld);
3419  }
3420 
3421  // GNU C permits a K&R definition to follow a prototype declaration
3422  // if the declared types of the parameters in the K&R definition
3423  // match the types in the prototype declaration, even when the
3424  // promoted types of the parameters from the K&R definition differ
3425  // from the types in the prototype. GCC then keeps the types from
3426  // the prototype.
3427  //
3428  // If a variadic prototype is followed by a non-variadic K&R definition,
3429  // the K&R definition becomes variadic. This is sort of an edge case, but
3430  // it's legal per the standard depending on how you read C99 6.7.5.3p15 and
3431  // C99 6.9.1p8.
3432  if (!getLangOpts().CPlusPlus &&
3433  Old->hasPrototype() && !New->hasPrototype() &&
3434  New->getType()->getAs<FunctionProtoType>() &&
3435  Old->getNumParams() == New->getNumParams()) {
3436  SmallVector<QualType, 16> ArgTypes;
3438  const FunctionProtoType *OldProto
3439  = Old->getType()->getAs<FunctionProtoType>();
3440  const FunctionProtoType *NewProto
3441  = New->getType()->getAs<FunctionProtoType>();
3442 
3443  // Determine whether this is the GNU C extension.
3444  QualType MergedReturn = Context.mergeTypes(OldProto->getReturnType(),
3445  NewProto->getReturnType());
3446  bool LooseCompatible = !MergedReturn.isNull();
3447  for (unsigned Idx = 0, End = Old->getNumParams();
3448  LooseCompatible && Idx != End; ++Idx) {
3449  ParmVarDecl *OldParm = Old->getParamDecl(Idx);
3450  ParmVarDecl *NewParm = New->getParamDecl(Idx);
3451  if (Context.typesAreCompatible(OldParm->getType(),
3452  NewProto->getParamType(Idx))) {
3453  ArgTypes.push_back(NewParm->getType());
3454  } else if (Context.typesAreCompatible(OldParm->getType(),
3455  NewParm->getType(),
3456  /*CompareUnqualified=*/true)) {
3457  GNUCompatibleParamWarning Warn = { OldParm, NewParm,
3458  NewProto->getParamType(Idx) };
3459  Warnings.push_back(Warn);
3460  ArgTypes.push_back(NewParm->getType());
3461  } else
3462  LooseCompatible = false;
3463  }
3464 
3465  if (LooseCompatible) {
3466  for (unsigned Warn = 0; Warn < Warnings.size(); ++Warn) {
3467  Diag(Warnings[Warn].NewParm->getLocation(),
3468  diag::ext_param_promoted_not_compatible_with_prototype)
3469  << Warnings[Warn].PromotedType
3470  << Warnings[Warn].OldParm->getType();
3471  if (Warnings[Warn].OldParm->getLocation().isValid())
3472  Diag(Warnings[Warn].OldParm->getLocation(),
3473  diag::note_previous_declaration);
3474  }
3475 
3476  if (MergeTypeWithOld)
3477  New->setType(Context.getFunctionType(MergedReturn, ArgTypes,
3478  OldProto->getExtProtoInfo()));
3479  return MergeCompatibleFunctionDecls(New, Old, S, MergeTypeWithOld);
3480  }
3481 
3482  // Fall through to diagnose conflicting types.
3483  }
3484 
3485  // A function that has already been declared has been redeclared or
3486  // defined with a different type; show an appropriate diagnostic.
3487 
3488  // If the previous declaration was an implicitly-generated builtin
3489  // declaration, then at the very least we should use a specialized note.
3490  unsigned BuiltinID;
3491  if (Old->isImplicit() && (BuiltinID = Old->getBuiltinID())) {
3492  // If it's actually a library-defined builtin function like 'malloc'
3493  // or 'printf', just warn about the incompatible redeclaration.
3494  if (Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID)) {
3495  Diag(New->getLocation(), diag::warn_redecl_library_builtin) << New;
3496  Diag(OldLocation, diag::note_previous_builtin_declaration)
3497  << Old << Old->getType();
3498 
3499  // If this is a global redeclaration, just forget hereafter
3500  // about the "builtin-ness" of the function.
3501  //
3502  // Doing this for local extern declarations is problematic. If
3503  // the builtin declaration remains visible, a second invalid
3504  // local declaration will produce a hard error; if it doesn't
3505  // remain visible, a single bogus local redeclaration (which is
3506  // actually only a warning) could break all the downstream code.
3508  New->getIdentifier()->revertBuiltin();
3509 
3510  return false;
3511  }
3512 
3513  PrevDiag = diag::note_previous_builtin_declaration;
3514  }
3515 
3516  Diag(New->getLocation(), diag::err_conflicting_types) << New->getDeclName();
3517  Diag(OldLocation, PrevDiag) << Old << Old->getType();
3518  return true;
3519 }
3520 
3521 /// \brief Completes the merge of two function declarations that are
3522 /// known to be compatible.
3523 ///
3524 /// This routine handles the merging of attributes and other
3525 /// properties of function declarations from the old declaration to
3526 /// the new declaration, once we know that New is in fact a
3527 /// redeclaration of Old.
3528 ///
3529 /// \returns false
3531  Scope *S, bool MergeTypeWithOld) {
3532  // Merge the attributes
3533  mergeDeclAttributes(New, Old);
3534 
3535  // Merge "pure" flag.
3536  if (Old->isPure())
3537  New->setPure();
3538 
3539  // Merge "used" flag.
3540  if (Old->getMostRecentDecl()->isUsed(false))
3541  New->setIsUsed();
3542 
3543  // Merge attributes from the parameters. These can mismatch with K&R
3544  // declarations.
3545  if (New->getNumParams() == Old->getNumParams())
3546  for (unsigned i = 0, e = New->getNumParams(); i != e; ++i) {
3547  ParmVarDecl *NewParam = New->getParamDecl(i);
3548  ParmVarDecl *OldParam = Old->getParamDecl(i);
3549  mergeParamDeclAttributes(NewParam, OldParam, *this);
3550  mergeParamDeclTypes(NewParam, OldParam, *this);
3551  }
3552 
3553  if (getLangOpts().CPlusPlus)
3554  return MergeCXXFunctionDecl(New, Old, S);
3555 
3556  // Merge the function types so the we get the composite types for the return
3557  // and argument types. Per C11 6.2.7/4, only update the type if the old decl
3558  // was visible.
3559  QualType Merged = Context.mergeTypes(Old->getType(), New->getType());
3560  if (!Merged.isNull() && MergeTypeWithOld)
3561  New->setType(Merged);
3562 
3563  return false;
3564 }
3565 
3567  ObjCMethodDecl *oldMethod) {
3568  // Merge the attributes, including deprecated/unavailable
3569  AvailabilityMergeKind MergeKind =
3570  isa<ObjCProtocolDecl>(oldMethod->getDeclContext())
3571  ? AMK_ProtocolImplementation
3572  : isa<ObjCImplDecl>(newMethod->getDeclContext()) ? AMK_Redeclaration
3573  : AMK_Override;
3574 
3575  mergeDeclAttributes(newMethod, oldMethod, MergeKind);
3576 
3577  // Merge attributes from the parameters.
3579  oe = oldMethod->param_end();
3581  ni = newMethod->param_begin(), ne = newMethod->param_end();
3582  ni != ne && oi != oe; ++ni, ++oi)
3583  mergeParamDeclAttributes(*ni, *oi, *this);
3584 }
3585 
3586 static void diagnoseVarDeclTypeMismatch(Sema &S, VarDecl *New, VarDecl* Old) {
3587  assert(!S.Context.hasSameType(New->getType(), Old->getType()));
3588 
3590  ? diag::err_redefinition_different_type
3591  : diag::err_redeclaration_different_type)
3592  << New->getDeclName() << New->getType() << Old->getType();
3593 
3594  diag::kind PrevDiag;
3595  SourceLocation OldLocation;
3596  std::tie(PrevDiag, OldLocation)
3598  S.Diag(OldLocation, PrevDiag);
3599  New->setInvalidDecl();
3600 }
3601 
3602 /// MergeVarDeclTypes - We parsed a variable 'New' which has the same name and
3603 /// scope as a previous declaration 'Old'. Figure out how to merge their types,
3604 /// emitting diagnostics as appropriate.
3605 ///
3606 /// Declarations using the auto type specifier (C++ [decl.spec.auto]) call back
3607 /// to here in AddInitializerToDecl. We can't check them before the initializer
3608 /// is attached.
3610  bool MergeTypeWithOld) {
3611  if (New->isInvalidDecl() || Old->isInvalidDecl())
3612  return;
3613 
3614  QualType MergedT;
3615  if (getLangOpts().CPlusPlus) {
3616  if (New->getType()->isUndeducedType()) {
3617  // We don't know what the new type is until the initializer is attached.
3618  return;
3619  } else if (Context.hasSameType(New->getType(), Old->getType())) {
3620  // These could still be something that needs exception specs checked.
3621  return MergeVarDeclExceptionSpecs(New, Old);
3622  }
3623  // C++ [basic.link]p10:
3624  // [...] the types specified by all declarations referring to a given
3625  // object or function shall be identical, except that declarations for an
3626  // array object can specify array types that differ by the presence or
3627  // absence of a major array bound (8.3.4).
3628  else if (Old->getType()->isArrayType() && New->getType()->isArrayType()) {
3629  const ArrayType *OldArray = Context.getAsArrayType(Old->getType());
3630  const ArrayType *NewArray = Context.getAsArrayType(New->getType());
3631 
3632  // We are merging a variable declaration New into Old. If it has an array
3633  // bound, and that bound differs from Old's bound, we should diagnose the
3634  // mismatch.
3635  if (!NewArray->isIncompleteArrayType() && !NewArray->isDependentType()) {
3636  for (VarDecl *PrevVD = Old->getMostRecentDecl(); PrevVD;
3637  PrevVD = PrevVD->getPreviousDecl()) {
3638  const ArrayType *PrevVDTy = Context.getAsArrayType(PrevVD->getType());
3639  if (PrevVDTy->isIncompleteArrayType() || PrevVDTy->isDependentType())
3640  continue;
3641 
3642  if (!Context.hasSameType(NewArray, PrevVDTy))
3643  return diagnoseVarDeclTypeMismatch(*this, New, PrevVD);
3644  }
3645  }
3646 
3647  if (OldArray->isIncompleteArrayType() && NewArray->isArrayType()) {
3648  if (Context.hasSameType(OldArray->getElementType(),
3649  NewArray->getElementType()))
3650  MergedT = New->getType();
3651  }
3652  // FIXME: Check visibility. New is hidden but has a complete type. If New
3653  // has no array bound, it should not inherit one from Old, if Old is not
3654  // visible.
3655  else if (OldArray->isArrayType() && NewArray->isIncompleteArrayType()) {
3656  if (Context.hasSameType(OldArray->getElementType(),
3657  NewArray->getElementType()))
3658  MergedT = Old->getType();
3659  }
3660  }
3661  else if (New->getType()->isObjCObjectPointerType() &&
3662  Old->getType()->isObjCObjectPointerType()) {
3663  MergedT = Context.mergeObjCGCQualifiers(New->getType(),
3664  Old->getType());
3665  }
3666  } else {
3667  // C 6.2.7p2:
3668  // All declarations that refer to the same object or function shall have
3669  // compatible type.
3670  MergedT = Context.mergeTypes(New->getType(), Old->getType());
3671  }
3672  if (MergedT.isNull()) {
3673  // It's OK if we couldn't merge types if either type is dependent, for a
3674  // block-scope variable. In other cases (static data members of class
3675  // templates, variable templates, ...), we require the types to be
3676  // equivalent.
3677  // FIXME: The C++ standard doesn't say anything about this.
3678  if ((New->getType()->isDependentType() ||
3679  Old->getType()->isDependentType()) && New->isLocalVarDecl()) {
3680  // If the old type was dependent, we can't merge with it, so the new type
3681  // becomes dependent for now. We'll reproduce the original type when we
3682  // instantiate the TypeSourceInfo for the variable.
3683  if (!New->getType()->isDependentType() && MergeTypeWithOld)
3684  New->setType(Context.DependentTy);
3685  return;
3686  }
3687  return diagnoseVarDeclTypeMismatch(*this, New, Old);
3688  }
3689 
3690  // Don't actually update the type on the new declaration if the old
3691  // declaration was an extern declaration in a different scope.
3692  if (MergeTypeWithOld)
3693  New->setType(MergedT);
3694 }
3695 
3696 static bool mergeTypeWithPrevious(Sema &S, VarDecl *NewVD, VarDecl *OldVD,
3698  // C11 6.2.7p4:
3699  // For an identifier with internal or external linkage declared
3700  // in a scope in which a prior declaration of that identifier is
3701  // visible, if the prior declaration specifies internal or
3702  // external linkage, the type of the identifier at the later
3703  // declaration becomes the composite type.
3704  //
3705  // If the variable isn't visible, we do not merge with its type.
3706  if (Previous.isShadowed())
3707  return false;
3708 
3709  if (S.getLangOpts().CPlusPlus) {
3710  // C++11 [dcl.array]p3:
3711  // If there is a preceding declaration of the entity in the same
3712  // scope in which the bound was specified, an omitted array bound
3713  // is taken to be the same as in that earlier declaration.
3714  return NewVD->isPreviousDeclInSameBlockScope() ||
3715  (!OldVD->getLexicalDeclContext()->isFunctionOrMethod() &&
3717  } else {
3718  // If the old declaration was function-local, don't merge with its
3719  // type unless we're in the same function.
3720  return !OldVD->getLexicalDeclContext()->isFunctionOrMethod() ||
3721  OldVD->getLexicalDeclContext() == NewVD->getLexicalDeclContext();
3722  }
3723 }
3724 
3725 /// MergeVarDecl - We just parsed a variable 'New' which has the same name
3726 /// and scope as a previous declaration 'Old'. Figure out how to resolve this
3727 /// situation, merging decls or emitting diagnostics as appropriate.
3728 ///
3729 /// Tentative definition rules (C99 6.9.2p2) are checked by
3730 /// FinalizeDeclaratorGroup. Unfortunately, we can't analyze tentative
3731 /// definitions here, since the initializer hasn't been attached.
3732 ///
3734  // If the new decl is already invalid, don't do any other checking.
3735  if (New->isInvalidDecl())
3736  return;
3737 
3738  if (!shouldLinkPossiblyHiddenDecl(Previous, New))
3739  return;
3740 
3741  VarTemplateDecl *NewTemplate = New->getDescribedVarTemplate();
3742 
3743  // Verify the old decl was also a variable or variable template.
3744  VarDecl *Old = nullptr;
3745  VarTemplateDecl *OldTemplate = nullptr;
3746  if (Previous.isSingleResult()) {
3747  if (NewTemplate) {
3748  OldTemplate = dyn_cast<VarTemplateDecl>(Previous.getFoundDecl());
3749  Old = OldTemplate ? OldTemplate->getTemplatedDecl() : nullptr;
3750 
3751  if (auto *Shadow =
3752  dyn_cast<UsingShadowDecl>(Previous.getRepresentativeDecl()))
3753  if (checkUsingShadowRedecl<VarTemplateDecl>(*this, Shadow, NewTemplate))
3754  return New->setInvalidDecl();
3755  } else {
3756  Old = dyn_cast<VarDecl>(Previous.getFoundDecl());
3757 
3758  if (auto *Shadow =
3759  dyn_cast<UsingShadowDecl>(Previous.getRepresentativeDecl()))
3760  if (checkUsingShadowRedecl<VarDecl>(*this, Shadow, New))
3761  return New->setInvalidDecl();
3762  }
3763  }
3764  if (!Old) {
3765  Diag(New->getLocation(), diag::err_redefinition_different_kind)
3766  << New->getDeclName();
3767  notePreviousDefinition(Previous.getRepresentativeDecl(),
3768  New->getLocation());
3769  return New->setInvalidDecl();
3770  }
3771 
3772  // Ensure the template parameters are compatible.
3773  if (NewTemplate &&
3774  !TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(),
3775  OldTemplate->getTemplateParameters(),
3776  /*Complain=*/true, TPL_TemplateMatch))
3777  return New->setInvalidDecl();
3778 
3779  // C++ [class.mem]p1:
3780  // A member shall not be declared twice in the member-specification [...]
3781  //
3782  // Here, we need only consider static data members.
3783  if (Old->isStaticDataMember() && !New->isOutOfLine()) {
3784  Diag(New->getLocation(), diag::err_duplicate_member)
3785  << New->getIdentifier();
3786  Diag(Old->getLocation(), diag::note_previous_declaration);
3787  New->setInvalidDecl();
3788  }
3789 
3790  mergeDeclAttributes(New, Old);
3791  // Warn if an already-declared variable is made a weak_import in a subsequent
3792  // declaration
3793  if (New->hasAttr<WeakImportAttr>() &&
3794  Old->getStorageClass() == SC_None &&
3795  !Old->hasAttr<WeakImportAttr>()) {
3796  Diag(New->getLocation(), diag::warn_weak_import) << New->getDeclName();
3797  notePreviousDefinition(Old, New->getLocation());
3798  // Remove weak_import attribute on new declaration.
3799  New->dropAttr<WeakImportAttr>();
3800  }
3801 
3802  if (New->hasAttr<InternalLinkageAttr>() &&
3803  !Old->hasAttr<InternalLinkageAttr>()) {
3804  Diag(New->getLocation(), diag::err_internal_linkage_redeclaration)
3805  << New->getDeclName();
3806  notePreviousDefinition(Old, New->getLocation());
3807  New->dropAttr<InternalLinkageAttr>();
3808  }
3809 
3810  // Merge the types.
3811  VarDecl *MostRecent = Old->getMostRecentDecl();
3812  if (MostRecent != Old) {
3813  MergeVarDeclTypes(New, MostRecent,
3814  mergeTypeWithPrevious(*this, New, MostRecent, Previous));
3815  if (New->isInvalidDecl())
3816  return;
3817  }
3818 
3819  MergeVarDeclTypes(New, Old, mergeTypeWithPrevious(*this, New, Old, Previous));
3820  if (New->isInvalidDecl())
3821  return;
3822 
3823  diag::kind PrevDiag;
3824  SourceLocation OldLocation;
3825  std::tie(PrevDiag, OldLocation) =
3827 
3828  // [dcl.stc]p8: Check if we have a non-static decl followed by a static.
3829  if (New->getStorageClass() == SC_Static &&
3830  !New->isStaticDataMember() &&
3831  Old->hasExternalFormalLinkage()) {
3832  if (getLangOpts().MicrosoftExt) {
3833  Diag(New->getLocation(), diag::ext_static_non_static)
3834  << New->getDeclName();
3835  Diag(OldLocation, PrevDiag);
3836  } else {
3837  Diag(New->getLocation(), diag::err_static_non_static)
3838  << New->getDeclName();
3839  Diag(OldLocation, PrevDiag);
3840  return New->setInvalidDecl();
3841  }
3842  }
3843  // C99 6.2.2p4:
3844  // For an identifier declared with the storage-class specifier
3845  // extern in a scope in which a prior declaration of that
3846  // identifier is visible,23) if the prior declaration specifies
3847  // internal or external linkage, the linkage of the identifier at
3848  // the later declaration is the same as the linkage specified at
3849  // the prior declaration. If no prior declaration is visible, or
3850  // if the prior declaration specifies no linkage, then the
3851  // identifier has external linkage.
3852  if (New->hasExternalStorage() && Old->hasLinkage())
3853  /* Okay */;
3854  else if (New->getCanonicalDecl()->getStorageClass() != SC_Static &&
3855  !New->isStaticDataMember() &&
3857  Diag(New->getLocation(), diag::err_non_static_static) << New->getDeclName();
3858  Diag(OldLocation, PrevDiag);
3859  return New->setInvalidDecl();
3860  }
3861 
3862  // Check if extern is followed by non-extern and vice-versa.
3863  if (New->hasExternalStorage() &&
3864  !Old->hasLinkage() && Old->isLocalVarDeclOrParm()) {
3865  Diag(New->getLocation(), diag::err_extern_non_extern) << New->getDeclName();
3866  Diag(OldLocation, PrevDiag);
3867  return New->setInvalidDecl();
3868  }
3869  if (Old->hasLinkage() && New->isLocalVarDeclOrParm() &&
3870  !New->hasExternalStorage()) {
3871  Diag(New->getLocation(), diag::err_non_extern_extern) << New->getDeclName();
3872  Diag(OldLocation, PrevDiag);
3873  return New->setInvalidDecl();
3874  }
3875 
3876  if (CheckRedeclarationModuleOwnership(New, Old))
3877  return;
3878 
3879  // Variables with external linkage are analyzed in FinalizeDeclaratorGroup.
3880 
3881  // FIXME: The test for external storage here seems wrong? We still
3882  // need to check for mismatches.
3883  if (!New->hasExternalStorage() && !New->isFileVarDecl() &&
3884  // Don't complain about out-of-line definitions of static members.
3885  !(Old->getLexicalDeclContext()->isRecord() &&
3886  !New->getLexicalDeclContext()->isRecord())) {
3887  Diag(New->getLocation(), diag::err_redefinition) << New->getDeclName();
3888  Diag(OldLocation, PrevDiag);
3889  return New->setInvalidDecl();
3890  }
3891 
3892  if (New->isInline() && !Old->getMostRecentDecl()->isInline()) {
3893  if (VarDecl *Def = Old->getDefinition()) {
3894  // C++1z [dcl.fcn.spec]p4:
3895  // If the definition of a variable appears in a translation unit before
3896  // its first declaration as inline, the program is ill-formed.
3897  Diag(New->getLocation(), diag::err_inline_decl_follows_def) << New;
3898  Diag(Def->getLocation(), diag::note_previous_definition);
3899  }
3900  }
3901 
3902  // If this redeclaration makes the variable inline, we may need to add it to
3903  // UndefinedButUsed.
3904  if (!Old->isInline() && New->isInline() && Old->isUsed(false) &&
3905  !Old->getDefinition() && !New->isThisDeclarationADefinition())
3906  UndefinedButUsed.insert(std::make_pair(Old->getCanonicalDecl(),
3907  SourceLocation()));
3908 
3909  if (New->getTLSKind() != Old->getTLSKind()) {
3910  if (!Old->getTLSKind()) {
3911  Diag(New->getLocation(), diag::err_thread_non_thread) << New->getDeclName();
3912  Diag(OldLocation, PrevDiag);
3913  } else if (!New->getTLSKind()) {
3914  Diag(New->getLocation(), diag::err_non_thread_thread) << New->getDeclName();
3915  Diag(OldLocation, PrevDiag);
3916  } else {
3917  // Do not allow redeclaration to change the variable between requiring
3918  // static and dynamic initialization.
3919  // FIXME: GCC allows this, but uses the TLS keyword on the first
3920  // declaration to determine the kind. Do we need to be compatible here?
3921  Diag(New->getLocation(), diag::err_thread_thread_different_kind)
3922  << New->getDeclName() << (New->getTLSKind() == VarDecl::TLS_Dynamic);
3923  Diag(OldLocation, PrevDiag);
3924  }
3925  }
3926 
3927  // C++ doesn't have tentative definitions, so go right ahead and check here.
3928  if (getLangOpts().CPlusPlus &&
3930  if (Old->isStaticDataMember() && Old->getCanonicalDecl()->isInline() &&
3931  Old->getCanonicalDecl()->isConstexpr()) {
3932  // This definition won't be a definition any more once it's been merged.
3933  Diag(New->getLocation(),
3934  diag::warn_deprecated_redundant_constexpr_static_def);
3935  } else if (VarDecl *Def = Old->getDefinition()) {
3936  if (checkVarDeclRedefinition(Def, New))
3937  return;
3938  }
3939  }
3940 
3941  if (haveIncompatibleLanguageLinkages(Old, New)) {
3942  Diag(New->getLocation(), diag::err_different_language_linkage) << New;
3943  Diag(OldLocation, PrevDiag);
3944  New->setInvalidDecl();
3945  return;
3946  }
3947 
3948  // Merge "used" flag.
3949  if (Old->getMostRecentDecl()->isUsed(false))
3950  New->setIsUsed();
3951 
3952  // Keep a chain of previous declarations.
3953  New->setPreviousDecl(Old);
3954  if (NewTemplate)
3955  NewTemplate->setPreviousDecl(OldTemplate);
3956 
3957  // Inherit access appropriately.
3958  New->setAccess(Old->getAccess());
3959  if (NewTemplate)
3960  NewTemplate->setAccess(New->getAccess());
3961 
3962  if (Old->isInline())
3963  New->setImplicitlyInline();
3964 }
3965 
3967  SourceManager &SrcMgr = getSourceManager();
3968  auto FNewDecLoc = SrcMgr.getDecomposedLoc(New);
3969  auto FOldDecLoc = SrcMgr.getDecomposedLoc(Old->getLocation());
3970  auto *FNew = SrcMgr.getFileEntryForID(FNewDecLoc.first);
3971  auto *FOld = SrcMgr.getFileEntryForID(FOldDecLoc.first);
3972  auto &HSI = PP.getHeaderSearchInfo();
3973  StringRef HdrFilename =
3974  SrcMgr.getFilename(SrcMgr.getSpellingLoc(Old->getLocation()));
3975 
3976  auto noteFromModuleOrInclude = [&](Module *Mod,
3977  SourceLocation IncLoc) -> bool {
3978  // Redefinition errors with modules are common with non modular mapped
3979  // headers, example: a non-modular header H in module A that also gets
3980  // included directly in a TU. Pointing twice to the same header/definition
3981  // is confusing, try to get better diagnostics when modules is on.
3982  if (IncLoc.isValid()) {
3983  if (Mod) {
3984  Diag(IncLoc, diag::note_redefinition_modules_same_file)
3985  << HdrFilename.str() << Mod->getFullModuleName();
3986  if (!Mod->DefinitionLoc.isInvalid())
3987  Diag(Mod->DefinitionLoc, diag::note_defined_here)
3988  << Mod->getFullModuleName();
3989  } else {
3990  Diag(IncLoc, diag::note_redefinition_include_same_file)
3991  << HdrFilename.str();
3992  }
3993  return true;
3994  }
3995 
3996  return false;
3997  };
3998 
3999  // Is it the same file and same offset? Provide more information on why
4000  // this leads to a redefinition error.
4001  bool EmittedDiag = false;
4002  if (FNew == FOld && FNewDecLoc.second == FOldDecLoc.second) {
4003  SourceLocation OldIncLoc = SrcMgr.getIncludeLoc(FOldDecLoc.first);
4004  SourceLocation NewIncLoc = SrcMgr.getIncludeLoc(FNewDecLoc.first);
4005  EmittedDiag = noteFromModuleOrInclude(Old->getOwningModule(), OldIncLoc);
4006  EmittedDiag |= noteFromModuleOrInclude(getCurrentModule(), NewIncLoc);
4007 
4008  // If the header has no guards, emit a note suggesting one.
4009  if (FOld && !HSI.isFileMultipleIncludeGuarded(FOld))
4010  Diag(Old->getLocation(), diag::note_use_ifdef_guards);
4011 
4012  if (EmittedDiag)
4013  return;
4014  }
4015 
4016  // Redefinition coming from different files or couldn't do better above.
4017  Diag(Old->getLocation(), diag::note_previous_definition);
4018 }
4019 
4020 /// We've just determined that \p Old and \p New both appear to be definitions
4021 /// of the same variable. Either diagnose or fix the problem.
4023  if (!hasVisibleDefinition(Old) &&
4024  (New->getFormalLinkage() == InternalLinkage ||
4025  New->isInline() ||
4026  New->getDescribedVarTemplate() ||
4028  New->getDeclContext()->isDependentContext())) {
4029  // The previous definition is hidden, and multiple definitions are
4030  // permitted (in separate TUs). Demote this to a declaration.
4032 
4033  // Make the canonical definition visible.
4034  if (auto *OldTD = Old->getDescribedVarTemplate())
4035  makeMergedDefinitionVisible(OldTD);
4036  makeMergedDefinitionVisible(Old);
4037  return false;
4038  } else {
4039  Diag(New->getLocation(), diag::err_redefinition) << New;
4040  notePreviousDefinition(Old, New->getLocation());
4041  New->setInvalidDecl();
4042  return true;
4043  }
4044 }
4045 
4046 /// ParsedFreeStandingDeclSpec - This method is invoked when a declspec with
4047 /// no declarator (e.g. "struct foo;") is parsed.
4048 Decl *
4050  RecordDecl *&AnonRecord) {
4051  return ParsedFreeStandingDeclSpec(S, AS, DS, MultiTemplateParamsArg(), false,
4052  AnonRecord);
4053 }
4054 
4055 // The MS ABI changed between VS2013 and VS2015 with regard to numbers used to
4056 // disambiguate entities defined in different scopes.
4057 // While the VS2015 ABI fixes potential miscompiles, it is also breaks
4058 // compatibility.
4059 // We will pick our mangling number depending on which version of MSVC is being
4060 // targeted.
4061 static unsigned getMSManglingNumber(const LangOptions &LO, Scope *S) {
4063  ? S->getMSCurManglingNumber()
4064  : S->getMSLastManglingNumber();
4065 }
4066 
4067 void Sema::handleTagNumbering(const TagDecl *Tag, Scope *TagScope) {
4068  if (!Context.getLangOpts().CPlusPlus)
4069  return;
4070 
4071  if (isa<CXXRecordDecl>(Tag->getParent())) {
4072  // If this tag is the direct child of a class, number it if
4073  // it is anonymous.
4074  if (!Tag->getName().empty() || Tag->getTypedefNameForAnonDecl())
4075  return;
4076  MangleNumberingContext &MCtx =
4077  Context.getManglingNumberContext(Tag->getParent());
4078  Context.setManglingNumber(
4079  Tag, MCtx.getManglingNumber(
4080  Tag, getMSManglingNumber(getLangOpts(), TagScope)));
4081  return;
4082  }
4083 
4084  // If this tag isn't a direct child of a class, number it if it is local.
4085  Decl *ManglingContextDecl;
4086  if (MangleNumberingContext *MCtx = getCurrentMangleNumberContext(
4087  Tag->getDeclContext(), ManglingContextDecl)) {
4088  Context.setManglingNumber(
4089  Tag, MCtx->getManglingNumber(
4090  Tag, getMSManglingNumber(getLangOpts(), TagScope)));
4091  }
4092 }
4093 
4095  TypedefNameDecl *NewTD) {
4096  if (TagFromDeclSpec->isInvalidDecl())
4097  return;
4098 
4099  // Do nothing if the tag already has a name for linkage purposes.
4100  if (TagFromDeclSpec->hasNameForLinkage())
4101  return;
4102 
4103  // A well-formed anonymous tag must always be a TUK_Definition.
4104  assert(TagFromDeclSpec->isThisDeclarationADefinition());
4105 
4106  // The type must match the tag exactly; no qualifiers allowed.
4107  if (!Context.hasSameType(NewTD->getUnderlyingType(),
4108  Context.getTagDeclType(TagFromDeclSpec))) {
4109  if (getLangOpts().CPlusPlus)
4110  Context.addTypedefNameForUnnamedTagDecl(TagFromDeclSpec, NewTD);
4111  return;
4112  }
4113 
4114  // If we've already computed linkage for the anonymous tag, then
4115  // adding a typedef name for the anonymous decl can change that
4116  // linkage, which might be a serious problem. Diagnose this as
4117  // unsupported and ignore the typedef name. TODO: we should
4118  // pursue this as a language defect and establish a formal rule
4119  // for how to handle it.
4120  if (TagFromDeclSpec->hasLinkageBeenComputed()) {
4121  Diag(NewTD->getLocation(), diag::err_typedef_changes_linkage);
4122 
4123  SourceLocation tagLoc = TagFromDeclSpec->getInnerLocStart();
4124  tagLoc = getLocForEndOfToken(tagLoc);
4125 
4126  llvm::SmallString<40> textToInsert;
4127  textToInsert += ' ';
4128  textToInsert += NewTD->getIdentifier()->getName();
4129  Diag(tagLoc, diag::note_typedef_changes_linkage)
4130  << FixItHint::CreateInsertion(tagLoc, textToInsert);
4131  return;
4132  }
4133 
4134  // Otherwise, set this is the anon-decl typedef for the tag.
4135  TagFromDeclSpec->setTypedefNameForAnonDecl(NewTD);
4136 }
4137 
4139  switch (T) {
4140  case DeclSpec::TST_class:
4141  return 0;
4142  case DeclSpec::TST_struct:
4143  return 1;
4145  return 2;
4146  case DeclSpec::TST_union:
4147  return 3;
4148  case DeclSpec::TST_enum:
4149  return 4;
4150  default:
4151  llvm_unreachable("unexpected type specifier");
4152  }
4153 }
4154 
4155 /// ParsedFreeStandingDeclSpec - This method is invoked when a declspec with
4156 /// no declarator (e.g. "struct foo;") is parsed. It also accepts template
4157 /// parameters to cope with template friend declarations.
4158 Decl *
4160  MultiTemplateParamsArg TemplateParams,
4161  bool IsExplicitInstantiation,
4162  RecordDecl *&AnonRecord) {
4163  Decl *TagD = nullptr;
4164  TagDecl *Tag = nullptr;
4165  if (DS.getTypeSpecType() == DeclSpec::TST_class ||
4170  TagD = DS.getRepAsDecl();
4171 
4172  if (!TagD) // We probably had an error
4173  return nullptr;
4174 
4175  // Note that the above type specs guarantee that the
4176  // type rep is a Decl, whereas in many of the others
4177  // it's a Type.
4178  if (isa<TagDecl>(TagD))
4179  Tag = cast<TagDecl>(TagD);
4180  else if (ClassTemplateDecl *CTD = dyn_cast<ClassTemplateDecl>(TagD))
4181  Tag = CTD->getTemplatedDecl();
4182  }
4183 
4184  if (Tag) {
4185  handleTagNumbering(Tag, S);
4186  Tag->setFreeStanding();
4187  if (Tag->isInvalidDecl())
4188  return Tag;
4189  }
4190 
4191  if (unsigned TypeQuals = DS.getTypeQualifiers()) {
4192  // Enforce C99 6.7.3p2: "Types other than pointer types derived from object
4193  // or incomplete types shall not be restrict-qualified."
4194  if (TypeQuals & DeclSpec::TQ_restrict)
4195  Diag(DS.getRestrictSpecLoc(),
4196  diag::err_typecheck_invalid_restrict_not_pointer_noarg)
4197  << DS.getSourceRange();
4198  }
4199 
4200  if (DS.isInlineSpecified())
4201  Diag(DS.getInlineSpecLoc(), diag::err_inline_non_function)
4202  << getLangOpts().CPlusPlus1z;
4203 
4204  if (DS.isConstexprSpecified()) {
4205  // C++0x [dcl.constexpr]p1: constexpr can only be applied to declarations
4206  // and definitions of functions and variables.
4207  if (Tag)
4208  Diag(DS.getConstexprSpecLoc(), diag::err_constexpr_tag)
4210  else
4211  Diag(DS.getConstexprSpecLoc(), diag::err_constexpr_no_declarators);
4212  // Don't emit warnings after this error.
4213  return TagD;
4214  }
4215 
4216  if (DS.isConceptSpecified()) {
4217  // C++ Concepts TS [dcl.spec.concept]p1: A concept definition refers to
4218  // either a function concept and its definition or a variable concept and
4219  // its initializer.
4220  Diag(DS.getConceptSpecLoc(), diag::err_concept_wrong_decl_kind);
4221  return TagD;
4222  }
4223 
4224  DiagnoseFunctionSpecifiers(DS);
4225 
4226  if (DS.isFriendSpecified()) {
4227  // If we're dealing with a decl but not a TagDecl, assume that
4228  // whatever routines created it handled the friendship aspect.
4229  if (TagD && !Tag)
4230  return nullptr;
4231  return ActOnFriendTypeDecl(S, DS, TemplateParams);
4232  }
4233 
4234  const CXXScopeSpec &SS = DS.getTypeSpecScope();
4235  bool IsExplicitSpecialization =
4236  !TemplateParams.empty() && TemplateParams.back()->size() == 0;
4237  if (Tag && SS.isNotEmpty() && !Tag->isCompleteDefinition() &&
4238  !IsExplicitInstantiation && !IsExplicitSpecialization &&
4239  !isa<ClassTemplatePartialSpecializationDecl>(Tag)) {
4240  // Per C++ [dcl.type.elab]p1, a class declaration cannot have a
4241  // nested-name-specifier unless it is an explicit instantiation
4242  // or an explicit specialization.
4243  //
4244  // FIXME: We allow class template partial specializations here too, per the
4245  // obvious intent of DR1819.
4246  //
4247  // Per C++ [dcl.enum]p1, an opaque-enum-declaration can't either.
4248  Diag(SS.getBeginLoc(), diag::err_standalone_class_nested_name_specifier)
4250  return nullptr;
4251  }
4252 
4253  // Track whether this decl-specifier declares anything.
4254  bool DeclaresAnything = true;
4255 
4256  // Handle anonymous struct definitions.
4257  if (RecordDecl *Record = dyn_cast_or_null<RecordDecl>(Tag)) {
4258  if (!Record->getDeclName() && Record->isCompleteDefinition() &&
4260  if (getLangOpts().CPlusPlus ||
4261  Record->getDeclContext()->isRecord()) {
4262  // If CurContext is a DeclContext that can contain statements,
4263  // RecursiveASTVisitor won't visit the decls that
4264  // BuildAnonymousStructOrUnion() will put into CurContext.
4265  // Also store them here so that they can be part of the
4266  // DeclStmt that gets created in this case.
4267  // FIXME: Also return the IndirectFieldDecls created by
4268  // BuildAnonymousStructOr union, for the same reason?
4269  if (CurContext->isFunctionOrMethod())
4270  AnonRecord = Record;
4271  return BuildAnonymousStructOrUnion(S, DS, AS, Record,
4272  Context.getPrintingPolicy());
4273  }
4274 
4275  DeclaresAnything = false;
4276  }
4277  }
4278 
4279  // C11 6.7.2.1p2:
4280  // A struct-declaration that does not declare an anonymous structure or
4281  // anonymous union shall contain a struct-declarator-list.
4282  //
4283  // This rule also existed in C89 and C99; the grammar for struct-declaration
4284  // did not permit a struct-declaration without a struct-declarator-list.
4285  if (!getLangOpts().CPlusPlus && CurContext->isRecord() &&
4287  // Check for Microsoft C extension: anonymous struct/union member.
4288  // Handle 2 kinds of anonymous struct/union:
4289  // struct STRUCT;
4290  // union UNION;
4291  // and
4292  // STRUCT_TYPE; <- where STRUCT_TYPE is a typedef struct.
4293  // UNION_TYPE; <- where UNION_TYPE is a typedef union.
4294  if ((Tag && Tag->getDeclName()) ||
4296  RecordDecl *Record = nullptr;
4297  if (Tag)
4298  Record = dyn_cast<RecordDecl>(Tag);
4299  else if (const RecordType *RT =
4301  Record = RT->getDecl();
4302  else if (const RecordType *UT = DS.getRepAsType().get()->getAsUnionType())
4303  Record = UT->getDecl();
4304 
4305  if (Record && getLangOpts().MicrosoftExt) {
4306  Diag(DS.getLocStart(), diag::ext_ms_anonymous_record)
4307  << Record->isUnion() << DS.getSourceRange();
4308  return BuildMicrosoftCAnonymousStruct(S, DS, Record);
4309  }
4310 
4311  DeclaresAnything = false;
4312  }
4313  }
4314 
4315  // Skip all the checks below if we have a type error.
4316  if (DS.getTypeSpecType() == DeclSpec::TST_error ||
4317  (TagD && TagD->isInvalidDecl()))
4318  return TagD;
4319 
4320  if (getLangOpts().CPlusPlus &&
4322  if (EnumDecl *Enum = dyn_cast_or_null<EnumDecl>(Tag))
4323  if (Enum->enumerator_begin() == Enum->enumerator_end() &&
4324  !Enum->getIdentifier() && !Enum->isInvalidDecl())
4325  DeclaresAnything = false;
4326 
4327  if (!DS.isMissingDeclaratorOk()) {
4328  // Customize diagnostic for a typedef missing a name.
4330  Diag(DS.getLocStart(), diag::ext_typedef_without_a_name)
4331  << DS.getSourceRange();
4332  else
4333  DeclaresAnything = false;
4334  }
4335 
4336  if (DS.isModulePrivateSpecified() &&
4337  Tag && Tag->getDeclContext()->isFunctionOrMethod())
4338  Diag(DS.getModulePrivateSpecLoc(), diag::err_module_private_local_class)
4339  << Tag->getTagKind()
4341 
4342  ActOnDocumentableDecl(TagD);
4343 
4344  // C 6.7/2:
4345  // A declaration [...] shall declare at least a declarator [...], a tag,
4346  // or the members of an enumeration.
4347  // C++ [dcl.dcl]p3:
4348  // [If there are no declarators], and except for the declaration of an
4349  // unnamed bit-field, the decl-specifier-seq shall introduce one or more
4350  // names into the program, or shall redeclare a name introduced by a
4351  // previous declaration.
4352  if (!DeclaresAnything) {
4353  // In C, we allow this as a (popular) extension / bug. Don't bother
4354  // producing further diagnostics for redundant qualifiers after this.
4355  Diag(DS.getLocStart(), diag::ext_no_declarators) << DS.getSourceRange();
4356  return TagD;
4357  }
4358 
4359  // C++ [dcl.stc]p1:
4360  // If a storage-class-specifier appears in a decl-specifier-seq, [...] the
4361  // init-declarator-list of the declaration shall not be empty.
4362  // C++ [dcl.fct.spec]p1:
4363  // If a cv-qualifier appears in a decl-specifier-seq, the
4364  // init-declarator-list of the declaration shall not be empty.
4365  //
4366  // Spurious qualifiers here appear to be valid in C.
4367  unsigned DiagID = diag::warn_standalone_specifier;
4368  if (getLangOpts().CPlusPlus)
4369  DiagID = diag::ext_standalone_specifier;
4370 
4371  // Note that a linkage-specification sets a storage class, but
4372  // 'extern "C" struct foo;' is actually valid and not theoretically
4373  // useless.
4374  if (DeclSpec::SCS SCS = DS.getStorageClassSpec()) {
4375  if (SCS == DeclSpec::SCS_mutable)
4376  // Since mutable is not a viable storage class specifier in C, there is
4377  // no reason to treat it as an extension. Instead, diagnose as an error.
4378  Diag(DS.getStorageClassSpecLoc(), diag::err_mutable_nonmember);
4379  else if (!DS.isExternInLinkageSpec() && SCS != DeclSpec::SCS_typedef)
4380  Diag(DS.getStorageClassSpecLoc(), DiagID)
4382  }
4383 
4384  if (DeclSpec::TSCS TSCS = DS.getThreadStorageClassSpec())
4385  Diag(DS.getThreadStorageClassSpecLoc(), DiagID)
4386  << DeclSpec::getSpecifierName(TSCS);
4387  if (DS.getTypeQualifiers()) {
4389  Diag(DS.getConstSpecLoc(), DiagID) << "const";
4391  Diag(DS.getConstSpecLoc(), DiagID) << "volatile";
4392  // Restrict is covered above.
4394  Diag(DS.getAtomicSpecLoc(), DiagID) << "_Atomic";
4396  Diag(DS.getUnalignedSpecLoc(), DiagID) << "__unaligned";
4397  }
4398 
4399  // Warn about ignored type attributes, for example:
4400  // __attribute__((aligned)) struct A;
4401  // Attributes should be placed after tag to apply to type declaration.
4402  if (!DS.getAttributes().empty()) {
4403  DeclSpec::TST TypeSpecType = DS.getTypeSpecType();
4404  if (TypeSpecType == DeclSpec::TST_class ||
4405  TypeSpecType == DeclSpec::TST_struct ||
4406  TypeSpecType == DeclSpec::TST_interface ||
4407  TypeSpecType == DeclSpec::TST_union ||
4408  TypeSpecType == DeclSpec::TST_enum) {
4409  for (AttributeList* attrs = DS.getAttributes().getList(); attrs;
4410  attrs = attrs->getNext())
4411  Diag(attrs->getLoc(), diag::warn_declspec_attribute_ignored)
4412  << attrs->getName() << GetDiagnosticTypeSpecifierID(TypeSpecType);
4413  }
4414  }
4415 
4416  return TagD;
4417 }
4418 
4419 /// We are trying to inject an anonymous member into the given scope;
4420 /// check if there's an existing declaration that can't be overloaded.
4421 ///
4422 /// \return true if this is a forbidden redeclaration
4423 static bool CheckAnonMemberRedeclaration(Sema &SemaRef,
4424  Scope *S,
4425  DeclContext *Owner,
4426  DeclarationName Name,
4427  SourceLocation NameLoc,
4428  bool IsUnion) {
4429  LookupResult R(SemaRef, Name, NameLoc, Sema::LookupMemberName,
4431  if (!SemaRef.LookupName(R, S)) return false;
4432 
4433  // Pick a representative declaration.
4435  assert(PrevDecl && "Expected a non-null Decl");
4436 
4437  if (!SemaRef.isDeclInScope(PrevDecl, Owner, S))
4438  return false;
4439 
4440  SemaRef.Diag(NameLoc, diag::err_anonymous_record_member_redecl)
4441  << IsUnion << Name;
4442  SemaRef.Diag(PrevDecl->getLocation(), diag::note_previous_declaration);
4443 
4444  return true;
4445 }
4446 
4447 /// InjectAnonymousStructOrUnionMembers - Inject the members of the
4448 /// anonymous struct or union AnonRecord into the owning context Owner
4449 /// and scope S. This routine will be invoked just after we realize
4450 /// that an unnamed union or struct is actually an anonymous union or
4451 /// struct, e.g.,
4452 ///
4453 /// @code
4454 /// union {
4455 /// int i;
4456 /// float f;
4457 /// }; // InjectAnonymousStructOrUnionMembers called here to inject i and
4458 /// // f into the surrounding scope.x
4459 /// @endcode
4460 ///
4461 /// This routine is recursive, injecting the names of nested anonymous
4462 /// structs/unions into the owning context and scope as well.
4463 static bool
4465  RecordDecl *AnonRecord, AccessSpecifier AS,
4466  SmallVectorImpl<NamedDecl *> &Chaining) {
4467  bool Invalid = false;
4468 
4469  // Look every FieldDecl and IndirectFieldDecl with a name.
4470  for (auto *D : AnonRecord->decls()) {
4471  if ((isa<FieldDecl>(D) || isa<IndirectFieldDecl>(D)) &&
4472  cast<NamedDecl>(D)->getDeclName()) {
4473  ValueDecl *VD = cast<ValueDecl>(D);
4474  if (CheckAnonMemberRedeclaration(SemaRef, S, Owner, VD->getDeclName(),
4475  VD->getLocation(),
4476  AnonRecord->isUnion())) {
4477  // C++ [class.union]p2:
4478  // The names of the members of an anonymous union shall be
4479  // distinct from the names of any other entity in the
4480  // scope in which the anonymous union is declared.
4481  Invalid = true;
4482  } else {
4483  // C++ [class.union]p2:
4484  // For the purpose of name lookup, after the anonymous union
4485  // definition, the members of the anonymous union are
4486  // considered to have been defined in the scope in which the
4487  // anonymous union is declared.
4488  unsigned OldChainingSize = Chaining.size();
4489  if (IndirectFieldDecl *IF = dyn_cast<IndirectFieldDecl>(VD))
4490  Chaining.append(IF->chain_begin(), IF->chain_end());
4491  else
4492  Chaining.push_back(VD);
4493 
4494  assert(Chaining.size() >= 2);
4495  NamedDecl **NamedChain =
4496  new (SemaRef.Context)NamedDecl*[Chaining.size()];
4497  for (unsigned i = 0; i < Chaining.size(); i++)
4498  NamedChain[i] = Chaining[i];
4499 
4501  SemaRef.Context, Owner, VD->getLocation(), VD->getIdentifier(),
4502  VD->getType(), {NamedChain, Chaining.size()});
4503 
4504  for (const auto *Attr : VD->attrs())
4505  IndirectField->addAttr(Attr->clone(SemaRef.Context));
4506 
4507  IndirectField->setAccess(AS);
4508  IndirectField->setImplicit();
4509  SemaRef.PushOnScopeChains(IndirectField, S);
4510 
4511  // That includes picking up the appropriate access specifier.
4512  if (AS != AS_none) IndirectField->setAccess(AS);
4513 
4514  Chaining.resize(OldChainingSize);
4515  }
4516  }
4517  }
4518 
4519  return Invalid;
4520 }
4521 
4522 /// StorageClassSpecToVarDeclStorageClass - Maps a DeclSpec::SCS to
4523 /// a VarDecl::StorageClass. Any error reporting is up to the caller:
4524 /// illegal input values are mapped to SC_None.
4525 static StorageClass
4527  DeclSpec::SCS StorageClassSpec = DS.getStorageClassSpec();
4528  assert(StorageClassSpec != DeclSpec::SCS_typedef &&
4529  "Parser allowed 'typedef' as storage class VarDecl.");
4530  switch (StorageClassSpec) {
4531  case DeclSpec::SCS_unspecified: return SC_None;
4532  case DeclSpec::SCS_extern:
4533  if (DS.isExternInLinkageSpec())
4534  return SC_None;
4535  return SC_Extern;
4536  case DeclSpec::SCS_static: return SC_Static;
4537  case DeclSpec::SCS_auto: return SC_Auto;
4538  case DeclSpec::SCS_register: return SC_Register;
4540  // Illegal SCSs map to None: error reporting is up to the caller.
4541  case DeclSpec::SCS_mutable: // Fall through.
4542  case DeclSpec::SCS_typedef: return SC_None;
4543  }
4544  llvm_unreachable("unknown storage class specifier");
4545 }
4546 
4548  assert(Record->hasInClassInitializer());
4549 
4550  for (const auto *I : Record->decls()) {
4551  const auto *FD = dyn_cast<FieldDecl>(I);
4552  if (const auto *IFD = dyn_cast<IndirectFieldDecl>(I))
4553  FD = IFD->getAnonField();
4554  if (FD && FD->hasInClassInitializer())
4555  return FD->getLocation();
4556  }
4557 
4558  llvm_unreachable("couldn't find in-class initializer");
4559 }
4560 
4562  SourceLocation DefaultInitLoc) {
4563  if (!Parent->isUnion() || !Parent->hasInClassInitializer())
4564  return;
4565 
4566  S.Diag(DefaultInitLoc, diag::err_multiple_mem_union_initialization);
4567  S.Diag(findDefaultInitializer(Parent), diag::note_previous_initializer) << 0;
4568 }
4569 
4571  CXXRecordDecl *AnonUnion) {
4572  if (!Parent->isUnion() || !Parent->hasInClassInitializer())
4573  return;
4574 
4575  checkDuplicateDefaultInit(S, Parent, findDefaultInitializer(AnonUnion));
4576 }
4577 
4578 /// BuildAnonymousStructOrUnion - Handle the declaration of an
4579 /// anonymous structure or union. Anonymous unions are a C++ feature
4580 /// (C++ [class.union]) and a C11 feature; anonymous structures
4581 /// are a C11 feature and GNU C++ extension.
4583  AccessSpecifier AS,
4584  RecordDecl *Record,
4585  const PrintingPolicy &Policy) {
4586  DeclContext *Owner = Record->getDeclContext();
4587 
4588  // Diagnose whether this anonymous struct/union is an extension.
4589  if (Record->isUnion() && !getLangOpts().CPlusPlus && !getLangOpts().C11)
4590  Diag(Record->getLocation(), diag::ext_anonymous_union);
4591  else if (!Record->isUnion() && getLangOpts().CPlusPlus)
4592  Diag(Record->getLocation(), diag::ext_gnu_anonymous_struct);
4593  else if (!Record->isUnion() && !getLangOpts().C11)
4594  Diag(Record->getLocation(), diag::ext_c11_anonymous_struct);
4595 
4596  // C and C++ require different kinds of checks for anonymous
4597  // structs/unions.
4598  bool Invalid = false;
4599  if (getLangOpts().CPlusPlus) {
4600  const char *PrevSpec = nullptr;
4601  unsigned DiagID;
4602  if (Record->isUnion()) {
4603  // C++ [class.union]p6:
4604  // Anonymous unions declared in a named namespace or in the
4605  // global namespace shall be declared static.
4607  (isa<TranslationUnitDecl>(Owner) ||
4608  (isa<NamespaceDecl>(Owner) &&
4609  cast<NamespaceDecl>(Owner)->getDeclName()))) {
4610  Diag(Record->getLocation(), diag::err_anonymous_union_not_static)
4611  << FixItHint::CreateInsertion(Record->getLocation(), "static ");
4612 
4613  // Recover by adding 'static'.
4615  PrevSpec, DiagID, Policy);
4616  }
4617  // C++ [class.union]p6:
4618  // A storage class is not allowed in a declaration of an
4619  // anonymous union in a class scope.
4621  isa<RecordDecl>(Owner)) {
4623  diag::err_anonymous_union_with_storage_spec)
4625 
4626  // Recover by removing the storage specifier.
4628  SourceLocation(),
4629  PrevSpec, DiagID, Context.getPrintingPolicy());
4630  }
4631  }
4632 
4633  // Ignore const/volatile/restrict qualifiers.
4634  if (DS.getTypeQualifiers()) {
4636  Diag(DS.getConstSpecLoc(), diag::ext_anonymous_struct_union_qualified)
4637  << Record->isUnion() << "const"
4640  Diag(DS.getVolatileSpecLoc(),
4641  diag::ext_anonymous_struct_union_qualified)
4642  << Record->isUnion() << "volatile"
4645  Diag(DS.getRestrictSpecLoc(),
4646  diag::ext_anonymous_struct_union_qualified)
4647  << Record->isUnion() << "restrict"
4650  Diag(DS.getAtomicSpecLoc(),
4651  diag::ext_anonymous_struct_union_qualified)
4652  << Record->isUnion() << "_Atomic"
4656  diag::ext_anonymous_struct_union_qualified)
4657  << Record->isUnion() << "__unaligned"
4659 
4660  DS.ClearTypeQualifiers();
4661  }
4662 
4663  // C++ [class.union]p2:
4664  // The member-specification of an anonymous union shall only
4665  // define non-static data members. [Note: nested types and
4666  // functions cannot be declared within an anonymous union. ]
4667  for (auto *Mem : Record->decls()) {
4668  if (auto *FD = dyn_cast<FieldDecl>(Mem)) {
4669  // C++ [class.union]p3:
4670  // An anonymous union shall not have private or protected
4671  // members (clause 11).
4672  assert(FD->getAccess() != AS_none);
4673  if (FD->getAccess() != AS_public) {
4674  Diag(FD->getLocation(), diag::err_anonymous_record_nonpublic_member)
4675  << Record->isUnion() << (FD->getAccess() == AS_protected);
4676  Invalid = true;
4677  }
4678 
4679  // C++ [class.union]p1
4680  // An object of a class with a non-trivial constructor, a non-trivial
4681  // copy constructor, a non-trivial destructor, or a non-trivial copy
4682  // assignment operator cannot be a member of a union, nor can an
4683  // array of such objects.
4684  if (CheckNontrivialField(FD))
4685  Invalid = true;
4686  } else if (Mem->isImplicit()) {
4687  // Any implicit members are fine.
4688  } else if (isa<TagDecl>(Mem) && Mem->getDeclContext() != Record) {
4689  // This is a type that showed up in an
4690  // elaborated-type-specifier inside the anonymous struct or
4691  // union, but which actually declares a type outside of the
4692  // anonymous struct or union. It's okay.
4693  } else if (auto *MemRecord = dyn_cast<RecordDecl>(Mem)) {
4694  if (!MemRecord->isAnonymousStructOrUnion() &&
4695  MemRecord->getDeclName()) {
4696  // Visual C++ allows type definition in anonymous struct or union.
4697  if (getLangOpts().MicrosoftExt)
4698  Diag(MemRecord->getLocation(), diag::ext_anonymous_record_with_type)
4699  << Record->isUnion();
4700  else {
4701  // This is a nested type declaration.
4702  Diag(MemRecord->getLocation(), diag::err_anonymous_record_with_type)
4703  << Record->isUnion();
4704  Invalid = true;
4705  }
4706  } else {
4707  // This is an anonymous type definition within another anonymous type.
4708  // This is a popular extension, provided by Plan9, MSVC and GCC, but
4709  // not part of standard C++.
4710  Diag(MemRecord->getLocation(),
4711  diag::ext_anonymous_record_with_anonymous_type)
4712  << Record->isUnion();
4713  }
4714  } else if (isa<AccessSpecDecl>(Mem)) {
4715  // Any access specifier is fine.
4716  } else if (isa<StaticAssertDecl>(Mem)) {
4717  // In C++1z, static_assert declarations are also fine.
4718  } else {
4719  // We have something that isn't a non-static data
4720  // member. Complain about it.
4721  unsigned DK = diag::err_anonymous_record_bad_member;
4722  if (isa<TypeDecl>(Mem))
4723  DK = diag::err_anonymous_record_with_type;
4724  else if (isa<FunctionDecl>(Mem))
4725  DK = diag::err_anonymous_record_with_function;
4726  else if (isa<VarDecl>(Mem))
4727  DK = diag::err_anonymous_record_with_static;
4728 
4729  // Visual C++ allows type definition in anonymous struct or union.
4730  if (getLangOpts().MicrosoftExt &&
4731  DK == diag::err_anonymous_record_with_type)
4732  Diag(Mem->getLocation(), diag::ext_anonymous_record_with_type)
4733  << Record->isUnion();
4734  else {
4735  Diag(Mem->getLocation(), DK) << Record->isUnion();
4736  Invalid = true;
4737  }
4738  }
4739  }
4740 
4741  // C++11 [class.union]p8 (DR1460):
4742  // At most one variant member of a union may have a
4743  // brace-or-equal-initializer.
4744  if (cast<CXXRecordDecl>(Record)->hasInClassInitializer() &&
4745  Owner->isRecord())
4746  checkDuplicateDefaultInit(*this, cast<CXXRecordDecl>(Owner),
4747  cast<CXXRecordDecl>(Record));
4748  }
4749 
4750  if (!Record->isUnion() && !Owner->isRecord()) {
4751  Diag(Record->getLocation(), diag::err_anonymous_struct_not_member)
4752  << getLangOpts().CPlusPlus;
4753  Invalid = true;
4754  }
4755 
4756  // Mock up a declarator.
4758  TypeSourceInfo *TInfo = GetTypeForDeclarator(Dc, S);
4759  assert(TInfo && "couldn't build declarator info for anonymous struct/union");
4760 
4761  // Create a declaration for this anonymous struct/union.
4762  NamedDecl *Anon = nullptr;
4763  if (RecordDecl *OwningClass = dyn_cast<RecordDecl>(Owner)) {
4764  Anon = FieldDecl::Create(Context, OwningClass,
4765  DS.getLocStart(),
4766  Record->getLocation(),
4767  /*IdentifierInfo=*/nullptr,
4768  Context.getTypeDeclType(Record),
4769  TInfo,
4770  /*BitWidth=*/nullptr, /*Mutable=*/false,
4771  /*InitStyle=*/ICIS_NoInit);
4772  Anon->setAccess(AS);
4773  if (getLangOpts().CPlusPlus)
4774  FieldCollector->Add(cast<FieldDecl>(Anon));
4775  } else {
4776  DeclSpec::SCS SCSpec = DS.getStorageClassSpec();
4778  if (SCSpec == DeclSpec::SCS_mutable) {
4779  // mutable can only appear on non-static class members, so it's always
4780  // an error here
4781  Diag(Record->getLocation(), diag::err_mutable_nonmember);
4782  Invalid = true;
4783  SC = SC_None;
4784  }
4785 
4786  Anon = VarDecl::Create(Context, Owner,
4787  DS.getLocStart(),
4788  Record->getLocation(), /*IdentifierInfo=*/nullptr,
4789  Context.getTypeDeclType(Record),
4790  TInfo, SC);
4791 
4792  // Default-initialize the implicit variable. This initialization will be
4793  // trivial in almost all cases, except if a union member has an in-class
4794  // initializer:
4795  // union { int n = 0; };
4796  ActOnUninitializedDecl(Anon);
4797  }
4798  Anon->setImplicit();
4799 
4800  // Mark this as an anonymous struct/union type.
4801  Record->setAnonymousStructOrUnion(true);
4802 
4803  // Add the anonymous struct/union object to the current
4804  // context. We'll be referencing this object when we refer to one of
4805  // its members.
4806  Owner->addDecl(Anon);
4807 
4808  // Inject the members of the anonymous struct/union into the owning
4809  // context and into the identifier resolver chain for name lookup
4810  // purposes.
4812  Chain.push_back(Anon);
4813 
4814  if (InjectAnonymousStructOrUnionMembers(*this, S, Owner, Record, AS, Chain))
4815  Invalid = true;
4816 
4817  if (VarDecl *NewVD = dyn_cast<VarDecl>(Anon)) {
4818  if (getLangOpts().CPlusPlus && NewVD->isStaticLocal()) {
4819  Decl *ManglingContextDecl;
4820  if (MangleNumberingContext *MCtx = getCurrentMangleNumberContext(
4821  NewVD->getDeclContext(), ManglingContextDecl)) {
4822  Context.setManglingNumber(
4823  NewVD, MCtx->getManglingNumber(
4824  NewVD, getMSManglingNumber(getLangOpts(), S)));
4825  Context.setStaticLocalNumber(NewVD, MCtx->getStaticLocalNumber(NewVD));
4826  }
4827  }
4828  }
4829 
4830  if (Invalid)
4831  Anon->setInvalidDecl();
4832 
4833  return Anon;
4834 }
4835 
4836 /// BuildMicrosoftCAnonymousStruct - Handle the declaration of an
4837 /// Microsoft C anonymous structure.
4838 /// Ref: http://msdn.microsoft.com/en-us/library/z2cx9y4f.aspx
4839 /// Example:
4840 ///
4841 /// struct A { int a; };
4842 /// struct B { struct A; int b; };
4843 ///
4844 /// void foo() {
4845 /// B var;
4846 /// var.a = 3;
4847 /// }
4848 ///
4850  RecordDecl *Record) {
4851  assert(Record && "expected a record!");
4852 
4853  // Mock up a declarator.
4855  TypeSourceInfo *TInfo = GetTypeForDeclarator(Dc, S);
4856  assert(TInfo && "couldn't build declarator info for anonymous struct");
4857 
4858  auto *ParentDecl = cast<RecordDecl>(CurContext);
4859  QualType RecTy = Context.getTypeDeclType(Record);
4860 
4861  // Create a declaration for this anonymous struct.
4862  NamedDecl *Anon = FieldDecl::Create(Context,
4863  ParentDecl,
4864  DS.getLocStart(),
4865  DS.getLocStart(),
4866  /*IdentifierInfo=*/nullptr,
4867  RecTy,
4868  TInfo,
4869  /*BitWidth=*/nullptr, /*Mutable=*/false,
4870  /*InitStyle=*/ICIS_NoInit);
4871  Anon->setImplicit();
4872 
4873  // Add the anonymous struct object to the current context.
4874  CurContext->addDecl(Anon);
4875 
4876  // Inject the members of the anonymous struct into the current
4877  // context and into the identifier resolver chain for name lookup
4878  // purposes.
4880  Chain.push_back(Anon);
4881 
4882  RecordDecl *RecordDef = Record->getDefinition();
4883  if (RequireCompleteType(Anon->getLocation(), RecTy,
4884  diag::err_field_incomplete) ||
4885  InjectAnonymousStructOrUnionMembers(*this, S, CurContext, RecordDef,
4886  AS_none, Chain)) {
4887  Anon->setInvalidDecl();
4888  ParentDecl->setInvalidDecl();
4889  }
4890 
4891  return Anon;
4892 }
4893 
4894 /// GetNameForDeclarator - Determine the full declaration name for the
4895 /// given Declarator.
4897  return GetNameFromUnqualifiedId(D.getName());
4898 }
4899 
4900 /// \brief Retrieves the declaration name from a parsed unqualified-id.
4903  DeclarationNameInfo NameInfo;
4904  NameInfo.setLoc(Name.StartLocation);
4905 
4906  switch (Name.getKind()) {
4907 
4910  NameInfo.setName(Name.Identifier);
4911  NameInfo.setLoc(Name.StartLocation);
4912  return NameInfo;
4913 
4915  // C++ [temp.deduct.guide]p3:
4916  // The simple-template-id shall name a class template specialization.
4917  // The template-name shall be the same identifier as the template-name
4918  // of the simple-template-id.
4919  // These together intend to imply that the template-name shall name a
4920  // class template.
4921  // FIXME: template<typename T> struct X {};
4922  // template<typename T> using Y = X<T>;
4923  // Y(int) -> Y<int>;
4924  // satisfies these rules but does not name a class template.
4925  TemplateName TN = Name.TemplateName.get().get();
4926  auto *Template = TN.getAsTemplateDecl();
4927  if (!Template || !isa<ClassTemplateDecl>(Template)) {
4928  Diag(Name.StartLocation,
4929  diag::err_deduction_guide_name_not_class_template)
4930  << (int)getTemplateNameKindForDiagnostics(TN) << TN;
4931  if (Template)
4932  Diag(Template->getLocation(), diag::note_template_decl_here);
4933  return DeclarationNameInfo();
4934  }
4935 
4936  NameInfo.setName(
4937  Context.DeclarationNames.getCXXDeductionGuideName(Template));
4938  NameInfo.setLoc(Name.StartLocation);
4939  return NameInfo;
4940  }
4941 
4943  NameInfo.setName(Context.DeclarationNames.getCXXOperatorName(
4945  NameInfo.setLoc(Name.StartLocation);
4949  = Name.EndLocation.getRawEncoding();
4950  return NameInfo;
4951 
4954  Name.Identifier));
4955  NameInfo.setLoc(Name.StartLocation);
4957  return NameInfo;
4958 
4960  TypeSourceInfo *TInfo;
4961  QualType Ty = GetTypeFromParser(Name.ConversionFunctionId, &TInfo);
4962  if (Ty.isNull())
4963  return DeclarationNameInfo();
4965  Context.getCanonicalType(Ty)));
4966  NameInfo.setLoc(Name.StartLocation);
4967  NameInfo.setNamedTypeInfo(TInfo);
4968  return NameInfo;
4969  }
4970 
4972  TypeSourceInfo *TInfo;
4973  QualType Ty = GetTypeFromParser(Name.ConstructorName, &TInfo);
4974  if (Ty.isNull())
4975  return DeclarationNameInfo();
4977  Context.getCanonicalType(Ty)));
4978  NameInfo.setLoc(Name.StartLocation);
4979  NameInfo.setNamedTypeInfo(TInfo);
4980  return NameInfo;
4981  }
4982 
4984  // In well-formed code, we can only have a constructor
4985  // template-id that refers to the current context, so go there
4986  // to find the actual type being constructed.
4987  CXXRecordDecl *CurClass = dyn_cast<CXXRecordDecl>(CurContext);
4988  if (!CurClass || CurClass->getIdentifier() != Name.TemplateId->Name)
4989  return DeclarationNameInfo();
4990 
4991  // Determine the type of the class being constructed.
4992  QualType CurClassType = Context.getTypeDeclType(CurClass);
4993 
4994  // FIXME: Check two things: that the template-id names the same type as
4995  // CurClassType, and that the template-id does not occur when the name
4996  // was qualified.
4997 
4999  Context.getCanonicalType(CurClassType)));
5000  NameInfo.setLoc(Name.StartLocation);
5001  // FIXME: should we retrieve TypeSourceInfo?
5002  NameInfo.setNamedTypeInfo(nullptr);
5003  return NameInfo;
5004  }
5005 
5007  TypeSourceInfo *TInfo;
5008  QualType Ty = GetTypeFromParser(Name.DestructorName, &TInfo);
5009  if (Ty.isNull())
5010  return DeclarationNameInfo();
5012  Context.getCanonicalType(Ty)));
5013  NameInfo.setLoc(Name.StartLocation);
5014  NameInfo.setNamedTypeInfo(TInfo);
5015  return NameInfo;
5016  }
5017 
5019  TemplateName TName = Name.TemplateId->Template.get();
5020  SourceLocation TNameLoc = Name.TemplateId->TemplateNameLoc;
5021  return Context.getNameForTemplate(TName, TNameLoc);
5022  }
5023 
5024  } // switch (Name.getKind())
5025 
5026  llvm_unreachable("Unknown name kind");
5027 }
5028 
5030  do {
5031  if (Ty->isPointerType() || Ty->isReferenceType())
5032  Ty = Ty->getPointeeType();
5033  else if (Ty->isArrayType())
5034  Ty = Ty->castAsArrayTypeUnsafe()->getElementType();
5035  else
5036  return Ty.withoutLocalFastQualifiers();
5037  } while (true);
5038 }
5039 
5040 /// hasSimilarParameters - Determine whether the C++ functions Declaration
5041 /// and Definition have "nearly" matching parameters. This heuristic is
5042 /// used to improve diagnostics in the case where an out-of-line function
5043 /// definition doesn't match any declaration within the class or namespace.
5044 /// Also sets Params to the list of indices to the parameters that differ
5045 /// between the declaration and the definition. If hasSimilarParameters
5046 /// returns true and Params is empty, then all of the parameters match.
5047 static bool hasSimilarParameters(ASTContext &Context,
5048  FunctionDecl *Declaration,
5049  FunctionDecl *Definition,
5050  SmallVectorImpl<unsigned> &Params) {
5051  Params.clear();
5052  if (Declaration->param_size() != Definition->param_size())
5053  return false;
5054  for (unsigned Idx = 0; Idx < Declaration->param_size(); ++Idx) {
5055  QualType DeclParamTy = Declaration->getParamDecl(Idx)->getType();
5056  QualType DefParamTy = Definition->getParamDecl(Idx)->getType();
5057 
5058  // The parameter types are identical
5059  if (Context.hasSameType(DefParamTy, DeclParamTy))
5060  continue;
5061 
5062  QualType DeclParamBaseTy = getCoreType(DeclParamTy);
5063  QualType DefParamBaseTy = getCoreType(DefParamTy);
5064  const IdentifierInfo *DeclTyName = DeclParamBaseTy.getBaseTypeIdentifier();
5065  const IdentifierInfo *DefTyName = DefParamBaseTy.getBaseTypeIdentifier();
5066 
5067  if (Context.hasSameUnqualifiedType(DeclParamBaseTy, DefParamBaseTy) ||
5068  (DeclTyName && DeclTyName == DefTyName))
5069  Params.push_back(Idx);
5070  else // The two parameters aren't even close
5071  return false;
5072  }
5073 
5074  return true;
5075 }
5076 
5077 /// NeedsRebuildingInCurrentInstantiation - Checks whether the given
5078 /// declarator needs to be rebuilt in the current instantiation.
5079 /// Any bits of declarator which appear before the name are valid for
5080 /// consideration here. That's specifically the type in the decl spec
5081 /// and the base type in any member-pointer chunks.
5083  DeclarationName Name) {
5084  // The types we specifically need to rebuild are:
5085  // - typenames, typeofs, and decltypes
5086  // - types which will become injected class names
5087  // Of course, we also need to rebuild any type referencing such a
5088  // type. It's safest to just say "dependent", but we call out a
5089  // few cases here.
5090 
5091  DeclSpec &DS = D.getMutableDeclSpec();
5092  switch (DS.getTypeSpecType()) {
5096  case DeclSpec::TST_atomic: {
5097  // Grab the type from the parser.
5098  TypeSourceInfo *TSI = nullptr;
5099  QualType T = S.GetTypeFromParser(DS.getRepAsType(), &TSI);
5100  if (T.isNull() || !T->isDependentType()) break;
5101 
5102  // Make sure there's a type source info. This isn't really much
5103  // of a waste; most dependent types should have type source info
5104  // attached already.
5105  if (!TSI)
5107 
5108  // Rebuild the type in the current instantiation.
5109  TSI = S.RebuildTypeInCurrentInstantiation(TSI, D.getIdentifierLoc(), Name);
5110  if (!TSI) return true;
5111 
5112  // Store the new type back in the decl spec.
5113  ParsedType LocType = S.CreateParsedType(TSI->getType(), TSI);
5114  DS.UpdateTypeRep(LocType);
5115  break;
5116  }
5117 
5119  case DeclSpec::TST_typeofExpr: {
5120  Expr *E = DS.getRepAsExpr();
5122  if (Result.isInvalid()) return true;
5123  DS.UpdateExprRep(Result.get());
5124  break;
5125  }
5126 
5127  default:
5128  // Nothing to do for these decl specs.
5129  break;
5130  }
5131 
5132  // It doesn't matter what order we do this in.
5133  for (unsigned I = 0, E = D.getNumTypeObjects(); I != E; ++I) {
5134  DeclaratorChunk &Chunk = D.getTypeObject(I);
5135 
5136  // The only type information in the declarator which can come
5137  // before the declaration name is the base type of a member
5138  // pointer.
5139  if (Chunk.Kind != DeclaratorChunk::MemberPointer)
5140  continue;
5141 
5142  // Rebuild the scope specifier in-place.
5143  CXXScopeSpec &SS = Chunk.Mem.Scope();
5145  return true;
5146  }
5147 
5148  return false;
5149 }
5150 
5153  Decl *Dcl = HandleDeclarator(S, D, MultiTemplateParamsArg());
5154 
5155  if (OriginalLexicalContext && OriginalLexicalContext->isObjCContainer() &&
5156  Dcl && Dcl->getDeclContext()->isFileContext())
5158 
5159  if (getLangOpts().OpenCL)
5160  setCurrentOpenCLExtensionForDecl(Dcl);
5161 
5162  return Dcl;
5163 }
5164 
5165 /// DiagnoseClassNameShadow - Implement C++ [class.mem]p13:
5166 /// If T is the name of a class, then each of the following shall have a
5167 /// name different from T:
5168 /// - every static data member of class T;
5169 /// - every member function of class T
5170 /// - every member of class T that is itself a type;
5171 /// \returns true if the declaration name violates these rules.
5173  DeclarationNameInfo NameInfo) {
5174  DeclarationName Name = NameInfo.getName();
5175 
5176  CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(DC);
5177  while (Record && Record->isAnonymousStructOrUnion())
5178  Record = dyn_cast<CXXRecordDecl>(Record->getParent());
5179  if (Record && Record->getIdentifier() && Record->getDeclName() == Name) {
5180  Diag(NameInfo.getLoc(), diag::err_member_name_of_class) << Name;
5181  return true;
5182  }
5183 
5184  return false;
5185 }
5186 
5187 /// \brief Diagnose a declaration whose declarator-id has the given
5188 /// nested-name-specifier.
5189 ///
5190 /// \param SS The nested-name-specifier of the declarator-id.
5191 ///
5192 /// \param DC The declaration context to which the nested-name-specifier
5193 /// resolves.
5194 ///
5195 /// \param Name The name of the entity being declared.
5196 ///
5197 /// \param Loc The location of the name of the entity being declared.
5198 ///
5199 /// \returns true if we cannot safely recover from this error, false otherwise.
5201  DeclarationName Name,
5202  SourceLocation Loc) {
5203  DeclContext *Cur = CurContext;
5204  while (isa<LinkageSpecDecl>(Cur) || isa<CapturedDecl>(Cur))
5205  Cur = Cur->getParent();
5206 
5207  // If the user provided a superfluous scope specifier that refers back to the
5208  // class in which the entity is already declared, diagnose and ignore it.
5209  //
5210  // class X {
5211  // void X::f();
5212  // };
5213  //
5214  // Note, it was once ill-formed to give redundant qualification in all
5215  // contexts, but that rule was removed by DR482.
5216  if (Cur->Equals(DC)) {
5217  if (Cur->isRecord()) {
5218  Diag(Loc, LangOpts.MicrosoftExt ? diag::warn_member_extra_qualification
5219  : diag::err_member_extra_qualification)
5220  << Name << FixItHint::CreateRemoval(SS.getRange());
5221  SS.clear();
5222  } else {
5223  Diag(Loc, diag::warn_namespace_member_extra_qualification) << Name;
5224  }
5225  return false;
5226  }
5227 
5228  // Check whether the qualifying scope encloses the scope of the original
5229  // declaration.
5230  if (!Cur->Encloses(DC)) {
5231  if (Cur->isRecord())
5232  Diag(Loc, diag::err_member_qualification)
5233  << Name << SS.getRange();
5234  else if (isa<TranslationUnitDecl>(DC))
5235  Diag(Loc, diag::err_invalid_declarator_global_scope)
5236  << Name << SS.getRange();
5237  else if (isa<FunctionDecl>(Cur))
5238  Diag(Loc, diag::err_invalid_declarator_in_function)
5239  << Name << SS.getRange();
5240  else if (isa<BlockDecl>(Cur))
5241  Diag(Loc, diag::err_invalid_declarator_in_block)
5242  << Name << SS.getRange();
5243  else
5244  Diag(Loc, diag::err_invalid_declarator_scope)
5245  << Name << cast<NamedDecl>(Cur) << cast<NamedDecl>(DC) << SS.getRange();
5246 
5247  return true;
5248  }
5249 
5250  if (Cur->isRecord()) {
5251  // Cannot qualify members within a class.
5252  Diag(Loc, diag::err_member_qualification)
5253  << Name << SS.getRange();
5254  SS.clear();
5255 
5256  // C++ constructors and destructors with incorrect scopes can break
5257  // our AST invariants by having the wrong underlying types. If
5258  // that's the case, then drop this declaration entirely.
5261  !Context.hasSameType(Name.getCXXNameType(),
5262  Context.getTypeDeclType(cast<CXXRecordDecl>(Cur))))
5263  return true;
5264 
5265  return false;
5266  }
5267 
5268  // C++11 [dcl.meaning]p1:
5269  // [...] "The nested-name-specifier of the qualified declarator-id shall
5270  // not begin with a decltype-specifer"
5271  NestedNameSpecifierLoc SpecLoc(SS.getScopeRep(), SS.location_data());
5272  while (SpecLoc.getPrefix())
5273  SpecLoc = SpecLoc.getPrefix();
5274  if (dyn_cast_or_null<DecltypeType>(
5275  SpecLoc.getNestedNameSpecifier()->getAsType()))
5276  Diag(Loc, diag::err_decltype_in_declarator)
5277  << SpecLoc.getTypeLoc().getSourceRange();
5278 
5279  return false;
5280 }
5281 
5283  MultiTemplateParamsArg TemplateParamLists) {
5284  // TODO: consider using NameInfo for diagnostic.
5285  DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
5286  DeclarationName Name = NameInfo.getName();
5287 
5288  // All of these full declarators require an identifier. If it doesn't have
5289  // one, the ParsedFreeStandingDeclSpec action should be used.
5290  if (D.isDecompositionDeclarator()) {
5291  return ActOnDecompositionDeclarator(S, D, TemplateParamLists);
5292  } else if (!Name) {
5293  if (!D.isInvalidType()) // Reject this if we think it is valid.
5295  diag::err_declarator_need_ident)
5296  << D.getDeclSpec().getSourceRange() << D.getSourceRange();
5297  return nullptr;
5298  } else if (DiagnoseUnexpandedParameterPack(NameInfo, UPPC_DeclarationType))
5299  return nullptr;
5300 
5301  // The scope passed in may not be a decl scope. Zip up the scope tree until
5302  // we find one that is.
5303  while ((S->getFlags() & Scope::DeclScope) == 0 ||
5304  (S->getFlags() & Scope::TemplateParamScope) != 0)
5305  S = S->getParent();
5306 
5307  DeclContext *DC = CurContext;
5308  if (D.getCXXScopeSpec().isInvalid())
5309  D.setInvalidType();
5310  else if (D.getCXXScopeSpec().isSet()) {
5311  if (DiagnoseUnexpandedParameterPack(D.getCXXScopeSpec(),
5312  UPPC_DeclarationQualifier))
5313  return nullptr;
5314 
5315  bool EnteringContext = !D.getDeclSpec().isFriendSpecified();
5316  DC = computeDeclContext(D.getCXXScopeSpec(), EnteringContext);
5317  if (!DC || isa<EnumDecl>(DC)) {
5318  // If we could not compute the declaration context, it's because the
5319  // declaration context is dependent but does not refer to a class,
5320  // class template, or class template partial specialization. Complain
5321  // and return early, to avoid the coming semantic disaster.
5322  Diag(D.getIdentifierLoc(),
5323  diag::err_template_qualified_declarator_no_match)
5324  << D.getCXXScopeSpec().getScopeRep()
5325  << D.getCXXScopeSpec().getRange();
5326  return nullptr;
5327  }
5328  bool IsDependentContext = DC->isDependentContext();
5329 
5330  if (!IsDependentContext &&
5331  RequireCompleteDeclContext(D.getCXXScopeSpec(), DC))
5332  return nullptr;
5333 
5334  // If a class is incomplete, do not parse entities inside it.
5335  if (isa<CXXRecordDecl>(DC) && !cast<CXXRecordDecl>(DC)->hasDefinition()) {
5336  Diag(D.getIdentifierLoc(),
5337  diag::err_member_def_undefined_record)
5338  << Name << DC << D.getCXXScopeSpec().getRange();
5339  return nullptr;
5340  }
5341  if (!D.getDeclSpec().isFriendSpecified()) {
5342  if (diagnoseQualifiedDeclaration(D.getCXXScopeSpec(), DC,
5343  Name, D.getIdentifierLoc())) {
5344  if (DC->isRecord())
5345  return nullptr;
5346 
5347  D.setInvalidType();
5348  }
5349  }
5350 
5351  // Check whether we need to rebuild the type of the given
5352  // declaration in the current instantiation.
5353  if (EnteringContext && IsDependentContext &&
5354  TemplateParamLists.size() != 0) {
5355  ContextRAII SavedContext(*this, DC);
5356  if (RebuildDeclaratorInCurrentInstantiation(*this, D, Name))
5357  D.setInvalidType();
5358  }
5359  }
5360 
5361  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
5362  QualType R = TInfo->getType();
5363 
5364  if (DiagnoseUnexpandedParameterPack(D.getIdentifierLoc(), TInfo,
5365  UPPC_DeclarationType))
5366  D.setInvalidType();
5367 
5368  LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
5369  forRedeclarationInCurContext());
5370 
5371  // See if this is a redefinition of a variable in the same scope.
5372  if (!D.getCXXScopeSpec().isSet()) {
5373  bool IsLinkageLookup = false;
5374  bool CreateBuiltins = false;
5375 
5376  // If the declaration we're planning to build will be a function
5377  // or object with linkage, then look for another declaration with
5378  // linkage (C99 6.2.2p4-5 and C++ [basic.link]p6).
5379  //
5380  // If the declaration we're planning to build will be declared with
5381  // external linkage in the translation unit, create any builtin with
5382  // the same name.
5384  /* Do nothing*/;
5385  else if (CurContext->isFunctionOrMethod() &&
5387  R->isFunctionType())) {
5388  IsLinkageLookup = true;
5389  CreateBuiltins =
5390  CurContext->getEnclosingNamespaceContext()->isTranslationUnit();
5391  } else if (CurContext->getRedeclContext()->isTranslationUnit() &&
5393  CreateBuiltins = true;
5394 
5395  if (IsLinkageLookup) {
5396  Previous.clear(LookupRedeclarationWithLinkage);
5397  Previous.setRedeclarationKind(ForExternalRedeclaration);
5398  }
5399 
5400  LookupName(Previous, S, CreateBuiltins);
5401  } else { // Something like "int foo::x;"
5402  LookupQualifiedName(Previous, DC);
5403 
5404  // C++ [dcl.meaning]p1:
5405  // When the declarator-id is qualified, the declaration shall refer to a
5406  // previously declared member of the class or namespace to which the
5407  // qualifier refers (or, in the case of a namespace, of an element of the
5408  // inline namespace set of that namespace (7.3.1)) or to a specialization
5409  // thereof; [...]
5410  //
5411  // Note that we already checked the context above, and that we do not have
5412  // enough information to make sure that Previous contains the declaration
5413  // we want to match. For example, given:
5414  //
5415  // class X {
5416  // void f();
5417  // void f(float);
5418  // };
5419  //
5420  // void X::f(int) { } // ill-formed
5421  //
5422  // In this case, Previous will point to the overload set
5423  // containing the two f's declared in X, but neither of them
5424  // matches.
5425 
5426  // C++ [dcl.meaning]p1:
5427  // [...] the member shall not merely have been introduced by a
5428  // using-declaration in the scope of the class or namespace nominated by
5429  // the nested-name-specifier of the declarator-id.
5430  RemoveUsingDecls(Previous);
5431  }
5432 
5433  if (Previous.isSingleResult() &&
5434  Previous.getFoundDecl()->isTemplateParameter()) {
5435  // Maybe we will complain about the shadowed template parameter.
5436  if (!D.isInvalidType())
5437  DiagnoseTemplateParameterShadow(D.getIdentifierLoc(),
5438  Previous.getFoundDecl());
5439 
5440  // Just pretend that we didn't see the previous declaration.
5441  Previous.clear();
5442  }
5443 
5444  if (!R->isFunctionType() && DiagnoseClassNameShadow(DC, NameInfo))
5445  // Forget that the previous declaration is the injected-class-name.
5446  Previous.clear();
5447 
5448  // In C++, the previous declaration we find might be a tag type
5449  // (class or enum). In this case, the new declaration will hide the
5450  // tag type. Note that this applies to functions, function templates, and
5451  // variables, but not to typedefs (C++ [dcl.typedef]p4) or variable templates.
5452  if (Previous.isSingleTagDecl() &&
5454  (TemplateParamLists.size() == 0 || R->isFunctionType()))
5455  Previous.clear();
5456 
5457  // Check that there are no default arguments other than in the parameters
5458  // of a function declaration (C++ only).
5459  if (getLangOpts().CPlusPlus)
5460  CheckExtraCXXDefaultArguments(D);
5461 
5462  if (D.getDeclSpec().isConceptSpecified()) {
5463  // C++ Concepts TS [dcl.spec.concept]p1: The concept specifier shall be
5464  // applied only to the definition of a function template or variable
5465  // template, declared in namespace scope
5466  if (!TemplateParamLists.size()) {
5468  diag:: err_concept_wrong_decl_kind);
5469  return nullptr;
5470  }
5471 
5472  if (!DC->getRedeclContext()->isFileContext()) {
5473  Diag(D.getIdentifierLoc(),
5474  diag::err_concept_decls_may_only_appear_in_namespace_scope);
5475  return nullptr;
5476  }
5477  }
5478 
5479  NamedDecl *New;
5480 
5481  bool AddToScope = true;
5483  if (TemplateParamLists.size()) {
5484  Diag(D.getIdentifierLoc(), diag::err_template_typedef);
5485  return nullptr;
5486  }
5487 
5488  New = ActOnTypedefDeclarator(S, D, DC, TInfo, Previous);
5489  } else if (R->isFunctionType()) {
5490  New = ActOnFunctionDeclarator(S, D, DC, TInfo, Previous,
5491  TemplateParamLists,
5492  AddToScope);
5493  } else {
5494  New = ActOnVariableDeclarator(S, D, DC, TInfo, Previous, TemplateParamLists,
5495  AddToScope);