Sema.cpp revision 467dc88512b4ba4bb16e274ea3771dc1415d31da 
1//===--- Sema.cpp - AST Builder and Semantic Analysis Implementation ------===//
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 the actions class which performs semantic analysis and
11// builds an AST out of a parse stream.
12//
13//===----------------------------------------------------------------------===//
14
15#include "clang/Sema/SemaInternal.h"
16#include "clang/Sema/DelayedDiagnostic.h"
17#include "TargetAttributesSema.h"
18#include "llvm/ADT/DenseMap.h"
19#include "llvm/ADT/SmallSet.h"
20#include "llvm/ADT/APFloat.h"
21#include "clang/Sema/CXXFieldCollector.h"
22#include "clang/Sema/TemplateDeduction.h"
23#include "clang/Sema/ExternalSemaSource.h"
24#include "clang/Sema/ObjCMethodList.h"
25#include "clang/Sema/PrettyDeclStackTrace.h"
26#include "clang/Sema/Scope.h"
27#include "clang/Sema/ScopeInfo.h"
28#include "clang/Sema/SemaConsumer.h"
29#include "clang/AST/ASTContext.h"
30#include "clang/AST/ASTDiagnostic.h"
31#include "clang/AST/DeclCXX.h"
32#include "clang/AST/DeclObjC.h"
33#include "clang/AST/Expr.h"
34#include "clang/AST/ExprCXX.h"
35#include "clang/AST/StmtCXX.h"
36#include "clang/Lex/Preprocessor.h"
37#include "clang/Basic/PartialDiagnostic.h"
38#include "clang/Basic/TargetInfo.h"
39using namespace clang;
40using namespace sema;
41
42FunctionScopeInfo::~FunctionScopeInfo() { }
43
44void FunctionScopeInfo::Clear() {
45  HasBranchProtectedScope = false;
46  HasBranchIntoScope = false;
47  HasIndirectGoto = false;
48
49  SwitchStack.clear();
50  Returns.clear();
51  ErrorTrap.reset();
52  PossiblyUnreachableDiags.clear();
53}
54
55BlockScopeInfo::~BlockScopeInfo() { }
56
57void Sema::ActOnTranslationUnitScope(Scope *S) {
58  TUScope = S;
59  PushDeclContext(S, Context.getTranslationUnitDecl());
60
61  VAListTagName = PP.getIdentifierInfo("__va_list_tag");
62
63  if (PP.getLangOptions().ObjC1) {
64    // Synthesize "@class Protocol;
65    if (Context.getObjCProtoType().isNull()) {
66      ObjCInterfaceDecl *ProtocolDecl =
67        ObjCInterfaceDecl::Create(Context, CurContext, SourceLocation(),
68                                  &Context.Idents.get("Protocol"),
69                                  SourceLocation(), true);
70      Context.setObjCProtoType(Context.getObjCInterfaceType(ProtocolDecl));
71      PushOnScopeChains(ProtocolDecl, TUScope, false);
72    }
73  }
74}
75
76Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
77           TranslationUnitKind TUKind,
78           CodeCompleteConsumer *CodeCompleter)
79  : TheTargetAttributesSema(0), FPFeatures(pp.getLangOptions()),
80    LangOpts(pp.getLangOptions()), PP(pp), Context(ctxt), Consumer(consumer),
81    Diags(PP.getDiagnostics()), SourceMgr(PP.getSourceManager()),
82    CollectStats(false), ExternalSource(0), CodeCompleter(CodeCompleter),
83    CurContext(0), PackContext(0), MSStructPragmaOn(false), VisContext(0),
84    ExprNeedsCleanups(0), LateTemplateParser(0), OpaqueParser(0),
85    IdResolver(pp.getLangOptions()), CXXTypeInfoDecl(0), MSVCGuidDecl(0),
86    GlobalNewDeleteDeclared(false),
87    ObjCShouldCallSuperDealloc(false),
88    TUKind(TUKind),
89    NumSFINAEErrors(0), SuppressAccessChecking(false),
90    AccessCheckingSFINAE(false), InNonInstantiationSFINAEContext(false),
91    NonInstantiationEntries(0), ArgumentPackSubstitutionIndex(-1),
92    CurrentInstantiationScope(0), TyposCorrected(0),
93    AnalysisWarnings(*this)
94{
95  TUScope = 0;
96  LoadedExternalKnownNamespaces = false;
97
98  if (getLangOptions().CPlusPlus)
99    FieldCollector.reset(new CXXFieldCollector());
100
101  // Tell diagnostics how to render things from the AST library.
102  PP.getDiagnostics().SetArgToStringFn(&FormatASTNodeDiagnosticArgument,
103                                       &Context);
104
105  ExprEvalContexts.push_back(
106        ExpressionEvaluationContextRecord(PotentiallyEvaluated, 0, false));
107
108  FunctionScopes.push_back(new FunctionScopeInfo(Diags));
109}
110
111void Sema::Initialize() {
112  // Tell the AST consumer about this Sema object.
113  Consumer.Initialize(Context);
114
115  // FIXME: Isn't this redundant with the initialization above?
116  if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
117    SC->InitializeSema(*this);
118
119  // Tell the external Sema source about this Sema object.
120  if (ExternalSemaSource *ExternalSema
121      = dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
122    ExternalSema->InitializeSema(*this);
123
124  // Initialize predefined 128-bit integer types, if needed.
125  if (PP.getTargetInfo().getPointerWidth(0) >= 64) {
126    // If either of the 128-bit integer types are unavailable to name lookup,
127    // define them now.
128    DeclarationName Int128 = &Context.Idents.get("__int128_t");
129    if (IdentifierResolver::begin(Int128) == IdentifierResolver::end())
130      PushOnScopeChains(Context.getInt128Decl(), TUScope);
131
132    DeclarationName UInt128 = &Context.Idents.get("__uint128_t");
133    if (IdentifierResolver::begin(UInt128) == IdentifierResolver::end())
134      PushOnScopeChains(Context.getUInt128Decl(), TUScope);
135  }
136
137
138  // Initialize predefined Objective-C types:
139  if (PP.getLangOptions().ObjC1) {
140    // If 'SEL' does not yet refer to any declarations, make it refer to the
141    // predefined 'SEL'.
142    DeclarationName SEL = &Context.Idents.get("SEL");
143    if (IdentifierResolver::begin(SEL) == IdentifierResolver::end())
144      PushOnScopeChains(Context.getObjCSelDecl(), TUScope);
145
146    // If 'id' does not yet refer to any declarations, make it refer to the
147    // predefined 'id'.
148    DeclarationName Id = &Context.Idents.get("id");
149    if (IdentifierResolver::begin(Id) == IdentifierResolver::end())
150      PushOnScopeChains(Context.getObjCIdDecl(), TUScope);
151
152    // Create the built-in typedef for 'Class'.
153    DeclarationName Class = &Context.Idents.get("Class");
154    if (IdentifierResolver::begin(Class) == IdentifierResolver::end())
155      PushOnScopeChains(Context.getObjCClassDecl(), TUScope);
156  }
157}
158
159Sema::~Sema() {
160  if (PackContext) FreePackedContext();
161  if (VisContext) FreeVisContext();
162  delete TheTargetAttributesSema;
163  MSStructPragmaOn = false;
164  // Kill all the active scopes.
165  for (unsigned I = 1, E = FunctionScopes.size(); I != E; ++I)
166    delete FunctionScopes[I];
167  if (FunctionScopes.size() == 1)
168    delete FunctionScopes[0];
169
170  // Tell the SemaConsumer to forget about us; we're going out of scope.
171  if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
172    SC->ForgetSema();
173
174  // Detach from the external Sema source.
175  if (ExternalSemaSource *ExternalSema
176        = dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
177    ExternalSema->ForgetSema();
178}
179
180
181/// makeUnavailableInSystemHeader - There is an error in the current
182/// context.  If we're still in a system header, and we can plausibly
183/// make the relevant declaration unavailable instead of erroring, do
184/// so and return true.
185bool Sema::makeUnavailableInSystemHeader(SourceLocation loc,
186                                         StringRef msg) {
187  // If we're not in a function, it's an error.
188  FunctionDecl *fn = dyn_cast<FunctionDecl>(CurContext);
189  if (!fn) return false;
190
191  // If we're in template instantiation, it's an error.
192  if (!ActiveTemplateInstantiations.empty())
193    return false;
194
195  // If that function's not in a system header, it's an error.
196  if (!Context.getSourceManager().isInSystemHeader(loc))
197    return false;
198
199  // If the function is already unavailable, it's not an error.
200  if (fn->hasAttr<UnavailableAttr>()) return true;
201
202  fn->addAttr(new (Context) UnavailableAttr(loc, Context, msg));
203  return true;
204}
205
206ASTMutationListener *Sema::getASTMutationListener() const {
207  return getASTConsumer().GetASTMutationListener();
208}
209
210/// \brief Print out statistics about the semantic analysis.
211void Sema::PrintStats() const {
212  llvm::errs() << "\n*** Semantic Analysis Stats:\n";
213  llvm::errs() << NumSFINAEErrors << " SFINAE diagnostics trapped.\n";
214
215  BumpAlloc.PrintStats();
216  AnalysisWarnings.PrintStats();
217}
218
219/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast.
220/// If there is already an implicit cast, merge into the existing one.
221/// The result is of the given category.
222ExprResult Sema::ImpCastExprToType(Expr *E, QualType Ty,
223                                   CastKind Kind, ExprValueKind VK,
224                                   const CXXCastPath *BasePath,
225                                   CheckedConversionKind CCK) {
226  QualType ExprTy = Context.getCanonicalType(E->getType());
227  QualType TypeTy = Context.getCanonicalType(Ty);
228
229  if (ExprTy == TypeTy)
230    return Owned(E);
231
232  if (getLangOptions().ObjCAutoRefCount)
233    CheckObjCARCConversion(SourceRange(), Ty, E, CCK);
234
235  // If this is a derived-to-base cast to a through a virtual base, we
236  // need a vtable.
237  if (Kind == CK_DerivedToBase &&
238      BasePathInvolvesVirtualBase(*BasePath)) {
239    QualType T = E->getType();
240    if (const PointerType *Pointer = T->getAs<PointerType>())
241      T = Pointer->getPointeeType();
242    if (const RecordType *RecordTy = T->getAs<RecordType>())
243      MarkVTableUsed(E->getLocStart(),
244                     cast<CXXRecordDecl>(RecordTy->getDecl()));
245  }
246
247  if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(E)) {
248    if (ImpCast->getCastKind() == Kind && (!BasePath || BasePath->empty())) {
249      ImpCast->setType(Ty);
250      ImpCast->setValueKind(VK);
251      return Owned(E);
252    }
253  }
254
255  return Owned(ImplicitCastExpr::Create(Context, Ty, Kind, E, BasePath, VK));
256}
257
258/// ScalarTypeToBooleanCastKind - Returns the cast kind corresponding
259/// to the conversion from scalar type ScalarTy to the Boolean type.
260CastKind Sema::ScalarTypeToBooleanCastKind(QualType ScalarTy) {
261  switch (ScalarTy->getScalarTypeKind()) {
262  case Type::STK_Bool: return CK_NoOp;
263  case Type::STK_Pointer: return CK_PointerToBoolean;
264  case Type::STK_MemberPointer: return CK_MemberPointerToBoolean;
265  case Type::STK_Integral: return CK_IntegralToBoolean;
266  case Type::STK_Floating: return CK_FloatingToBoolean;
267  case Type::STK_IntegralComplex: return CK_IntegralComplexToBoolean;
268  case Type::STK_FloatingComplex: return CK_FloatingComplexToBoolean;
269  }
270  return CK_Invalid;
271}
272
273ExprValueKind Sema::CastCategory(Expr *E) {
274  Expr::Classification Classification = E->Classify(Context);
275  return Classification.isRValue() ? VK_RValue :
276      (Classification.isLValue() ? VK_LValue : VK_XValue);
277}
278
279/// \brief Used to prune the decls of Sema's UnusedFileScopedDecls vector.
280static bool ShouldRemoveFromUnused(Sema *SemaRef, const DeclaratorDecl *D) {
281  if (D->isUsed())
282    return true;
283
284  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
285    // UnusedFileScopedDecls stores the first declaration.
286    // The declaration may have become definition so check again.
287    const FunctionDecl *DeclToCheck;
288    if (FD->hasBody(DeclToCheck))
289      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
290
291    // Later redecls may add new information resulting in not having to warn,
292    // so check again.
293    DeclToCheck = FD->getMostRecentDeclaration();
294    if (DeclToCheck != FD)
295      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
296  }
297
298  if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
299    // UnusedFileScopedDecls stores the first declaration.
300    // The declaration may have become definition so check again.
301    const VarDecl *DeclToCheck = VD->getDefinition();
302    if (DeclToCheck)
303      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
304
305    // Later redecls may add new information resulting in not having to warn,
306    // so check again.
307    DeclToCheck = VD->getMostRecentDeclaration();
308    if (DeclToCheck != VD)
309      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
310  }
311
312  return false;
313}
314
315namespace {
316  struct UndefinedInternal {
317    NamedDecl *decl;
318    FullSourceLoc useLoc;
319
320    UndefinedInternal(NamedDecl *decl, FullSourceLoc useLoc)
321      : decl(decl), useLoc(useLoc) {}
322  };
323
324  bool operator<(const UndefinedInternal &l, const UndefinedInternal &r) {
325    return l.useLoc.isBeforeInTranslationUnitThan(r.useLoc);
326  }
327}
328
329/// checkUndefinedInternals - Check for undefined objects with internal linkage.
330static void checkUndefinedInternals(Sema &S) {
331  if (S.UndefinedInternals.empty()) return;
332
333  // Collect all the still-undefined entities with internal linkage.
334  SmallVector<UndefinedInternal, 16> undefined;
335  for (llvm::DenseMap<NamedDecl*,SourceLocation>::iterator
336         i = S.UndefinedInternals.begin(), e = S.UndefinedInternals.end();
337       i != e; ++i) {
338    NamedDecl *decl = i->first;
339
340    // Ignore attributes that have become invalid.
341    if (decl->isInvalidDecl()) continue;
342
343    // __attribute__((weakref)) is basically a definition.
344    if (decl->hasAttr<WeakRefAttr>()) continue;
345
346    if (FunctionDecl *fn = dyn_cast<FunctionDecl>(decl)) {
347      if (fn->isPure() || fn->hasBody())
348        continue;
349    } else {
350      if (cast<VarDecl>(decl)->hasDefinition() != VarDecl::DeclarationOnly)
351        continue;
352    }
353
354    // We build a FullSourceLoc so that we can sort with array_pod_sort.
355    FullSourceLoc loc(i->second, S.Context.getSourceManager());
356    undefined.push_back(UndefinedInternal(decl, loc));
357  }
358
359  if (undefined.empty()) return;
360
361  // Sort (in order of use site) so that we're not (as) dependent on
362  // the iteration order through an llvm::DenseMap.
363  llvm::array_pod_sort(undefined.begin(), undefined.end());
364
365  for (SmallVectorImpl<UndefinedInternal>::iterator
366         i = undefined.begin(), e = undefined.end(); i != e; ++i) {
367    NamedDecl *decl = i->decl;
368    S.Diag(decl->getLocation(), diag::warn_undefined_internal)
369      << isa<VarDecl>(decl) << decl;
370    S.Diag(i->useLoc, diag::note_used_here);
371  }
372}
373
374void Sema::LoadExternalWeakUndeclaredIdentifiers() {
375  if (!ExternalSource)
376    return;
377
378  SmallVector<std::pair<IdentifierInfo *, WeakInfo>, 4> WeakIDs;
379  ExternalSource->ReadWeakUndeclaredIdentifiers(WeakIDs);
380  for (unsigned I = 0, N = WeakIDs.size(); I != N; ++I) {
381    llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator Pos
382      = WeakUndeclaredIdentifiers.find(WeakIDs[I].first);
383    if (Pos != WeakUndeclaredIdentifiers.end())
384      continue;
385
386    WeakUndeclaredIdentifiers.insert(WeakIDs[I]);
387  }
388}
389
390/// ActOnEndOfTranslationUnit - This is called at the very end of the
391/// translation unit when EOF is reached and all but the top-level scope is
392/// popped.
393void Sema::ActOnEndOfTranslationUnit() {
394  // Only complete translation units define vtables and perform implicit
395  // instantiations.
396  if (TUKind == TU_Complete) {
397    // If any dynamic classes have their key function defined within
398    // this translation unit, then those vtables are considered "used" and must
399    // be emitted.
400    for (DynamicClassesType::iterator I = DynamicClasses.begin(ExternalSource),
401                                      E = DynamicClasses.end();
402         I != E; ++I) {
403      assert(!(*I)->isDependentType() &&
404             "Should not see dependent types here!");
405      if (const CXXMethodDecl *KeyFunction = Context.getKeyFunction(*I)) {
406        const FunctionDecl *Definition = 0;
407        if (KeyFunction->hasBody(Definition))
408          MarkVTableUsed(Definition->getLocation(), *I, true);
409      }
410    }
411
412    // If DefinedUsedVTables ends up marking any virtual member functions it
413    // might lead to more pending template instantiations, which we then need
414    // to instantiate.
415    DefineUsedVTables();
416
417    // C++: Perform implicit template instantiations.
418    //
419    // FIXME: When we perform these implicit instantiations, we do not
420    // carefully keep track of the point of instantiation (C++ [temp.point]).
421    // This means that name lookup that occurs within the template
422    // instantiation will always happen at the end of the translation unit,
423    // so it will find some names that should not be found. Although this is
424    // common behavior for C++ compilers, it is technically wrong. In the
425    // future, we either need to be able to filter the results of name lookup
426    // or we need to perform template instantiations earlier.
427    PerformPendingInstantiations();
428  }
429
430  // Remove file scoped decls that turned out to be used.
431  UnusedFileScopedDecls.erase(std::remove_if(UnusedFileScopedDecls.begin(0,
432                                                                         true),
433                                             UnusedFileScopedDecls.end(),
434                              std::bind1st(std::ptr_fun(ShouldRemoveFromUnused),
435                                           this)),
436                              UnusedFileScopedDecls.end());
437
438  if (TUKind == TU_Prefix) {
439    // Translation unit prefixes don't need any of the checking below.
440    TUScope = 0;
441    return;
442  }
443
444  // Check for #pragma weak identifiers that were never declared
445  // FIXME: This will cause diagnostics to be emitted in a non-determinstic
446  // order!  Iterating over a densemap like this is bad.
447  LoadExternalWeakUndeclaredIdentifiers();
448  for (llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator
449       I = WeakUndeclaredIdentifiers.begin(),
450       E = WeakUndeclaredIdentifiers.end(); I != E; ++I) {
451    if (I->second.getUsed()) continue;
452
453    Diag(I->second.getLocation(), diag::warn_weak_identifier_undeclared)
454      << I->first;
455  }
456
457  if (TUKind == TU_Module) {
458    // Modules don't need any of the checking below.
459    TUScope = 0;
460    return;
461  }
462
463  // C99 6.9.2p2:
464  //   A declaration of an identifier for an object that has file
465  //   scope without an initializer, and without a storage-class
466  //   specifier or with the storage-class specifier static,
467  //   constitutes a tentative definition. If a translation unit
468  //   contains one or more tentative definitions for an identifier,
469  //   and the translation unit contains no external definition for
470  //   that identifier, then the behavior is exactly as if the
471  //   translation unit contains a file scope declaration of that
472  //   identifier, with the composite type as of the end of the
473  //   translation unit, with an initializer equal to 0.
474  llvm::SmallSet<VarDecl *, 32> Seen;
475  for (TentativeDefinitionsType::iterator
476            T = TentativeDefinitions.begin(ExternalSource),
477         TEnd = TentativeDefinitions.end();
478       T != TEnd; ++T)
479  {
480    VarDecl *VD = (*T)->getActingDefinition();
481
482    // If the tentative definition was completed, getActingDefinition() returns
483    // null. If we've already seen this variable before, insert()'s second
484    // return value is false.
485    if (VD == 0 || VD->isInvalidDecl() || !Seen.insert(VD))
486      continue;
487
488    if (const IncompleteArrayType *ArrayT
489        = Context.getAsIncompleteArrayType(VD->getType())) {
490      if (RequireCompleteType(VD->getLocation(),
491                              ArrayT->getElementType(),
492                              diag::err_tentative_def_incomplete_type_arr)) {
493        VD->setInvalidDecl();
494        continue;
495      }
496
497      // Set the length of the array to 1 (C99 6.9.2p5).
498      Diag(VD->getLocation(), diag::warn_tentative_incomplete_array);
499      llvm::APInt One(Context.getTypeSize(Context.getSizeType()), true);
500      QualType T = Context.getConstantArrayType(ArrayT->getElementType(),
501                                                One, ArrayType::Normal, 0);
502      VD->setType(T);
503    } else if (RequireCompleteType(VD->getLocation(), VD->getType(),
504                                   diag::err_tentative_def_incomplete_type))
505      VD->setInvalidDecl();
506
507    // Notify the consumer that we've completed a tentative definition.
508    if (!VD->isInvalidDecl())
509      Consumer.CompleteTentativeDefinition(VD);
510
511  }
512
513  if (LangOpts.CPlusPlus0x &&
514      Diags.getDiagnosticLevel(diag::warn_delegating_ctor_cycle,
515                               SourceLocation())
516        != Diagnostic::Ignored)
517    CheckDelegatingCtorCycles();
518
519  // If there were errors, disable 'unused' warnings since they will mostly be
520  // noise.
521  if (!Diags.hasErrorOccurred()) {
522    // Output warning for unused file scoped decls.
523    for (UnusedFileScopedDeclsType::iterator
524           I = UnusedFileScopedDecls.begin(ExternalSource),
525           E = UnusedFileScopedDecls.end(); I != E; ++I) {
526      if (ShouldRemoveFromUnused(this, *I))
527        continue;
528
529      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) {
530        const FunctionDecl *DiagD;
531        if (!FD->hasBody(DiagD))
532          DiagD = FD;
533        if (DiagD->isDeleted())
534          continue; // Deleted functions are supposed to be unused.
535        if (DiagD->isReferenced()) {
536          if (isa<CXXMethodDecl>(DiagD))
537            Diag(DiagD->getLocation(), diag::warn_unneeded_member_function)
538                  << DiagD->getDeclName();
539          else
540            Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
541                  << /*function*/0 << DiagD->getDeclName();
542        } else {
543          Diag(DiagD->getLocation(),
544               isa<CXXMethodDecl>(DiagD) ? diag::warn_unused_member_function
545                                         : diag::warn_unused_function)
546                << DiagD->getDeclName();
547        }
548      } else {
549        const VarDecl *DiagD = cast<VarDecl>(*I)->getDefinition();
550        if (!DiagD)
551          DiagD = cast<VarDecl>(*I);
552        if (DiagD->isReferenced()) {
553          Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
554                << /*variable*/1 << DiagD->getDeclName();
555        } else {
556          Diag(DiagD->getLocation(), diag::warn_unused_variable)
557                << DiagD->getDeclName();
558        }
559      }
560    }
561
562    checkUndefinedInternals(*this);
563  }
564
565  // Check we've noticed that we're no longer parsing the initializer for every
566  // variable. If we miss cases, then at best we have a performance issue and
567  // at worst a rejects-valid bug.
568  assert(ParsingInitForAutoVars.empty() &&
569         "Didn't unmark var as having its initializer parsed");
570
571  TUScope = 0;
572}
573
574
575//===----------------------------------------------------------------------===//
576// Helper functions.
577//===----------------------------------------------------------------------===//
578
579DeclContext *Sema::getFunctionLevelDeclContext() {
580  DeclContext *DC = CurContext;
581
582  while (isa<BlockDecl>(DC) || isa<EnumDecl>(DC))
583    DC = DC->getParent();
584
585  return DC;
586}
587
588/// getCurFunctionDecl - If inside of a function body, this returns a pointer
589/// to the function decl for the function being parsed.  If we're currently
590/// in a 'block', this returns the containing context.
591FunctionDecl *Sema::getCurFunctionDecl() {
592  DeclContext *DC = getFunctionLevelDeclContext();
593  return dyn_cast<FunctionDecl>(DC);
594}
595
596ObjCMethodDecl *Sema::getCurMethodDecl() {
597  DeclContext *DC = getFunctionLevelDeclContext();
598  return dyn_cast<ObjCMethodDecl>(DC);
599}
600
601NamedDecl *Sema::getCurFunctionOrMethodDecl() {
602  DeclContext *DC = getFunctionLevelDeclContext();
603  if (isa<ObjCMethodDecl>(DC) || isa<FunctionDecl>(DC))
604    return cast<NamedDecl>(DC);
605  return 0;
606}
607
608Sema::SemaDiagnosticBuilder::~SemaDiagnosticBuilder() {
609  if (!isActive())
610    return;
611
612  if (llvm::Optional<TemplateDeductionInfo*> Info = SemaRef.isSFINAEContext()) {
613    switch (DiagnosticIDs::getDiagnosticSFINAEResponse(getDiagID())) {
614    case DiagnosticIDs::SFINAE_Report:
615      // Fall through; we'll report the diagnostic below.
616      break;
617
618    case DiagnosticIDs::SFINAE_AccessControl:
619      // Per C++ Core Issue 1170, access control is part of SFINAE.
620      // Additionally, the AccessCheckingSFINAE flag can be used to temporary
621      // make access control a part of SFINAE for the purposes of checking
622      // type traits.
623      if (!SemaRef.AccessCheckingSFINAE &&
624          !SemaRef.getLangOptions().CPlusPlus0x)
625        break;
626
627    case DiagnosticIDs::SFINAE_SubstitutionFailure:
628      // Count this failure so that we know that template argument deduction
629      // has failed.
630      ++SemaRef.NumSFINAEErrors;
631      SemaRef.Diags.setLastDiagnosticIgnored();
632      SemaRef.Diags.Clear();
633      Clear();
634      return;
635
636    case DiagnosticIDs::SFINAE_Suppress:
637      // Make a copy of this suppressed diagnostic and store it with the
638      // template-deduction information;
639      FlushCounts();
640      DiagnosticInfo DiagInfo(&SemaRef.Diags);
641
642      if (*Info)
643        (*Info)->addSuppressedDiagnostic(DiagInfo.getLocation(),
644                        PartialDiagnostic(DiagInfo,
645                                          SemaRef.Context.getDiagAllocator()));
646
647      // Suppress this diagnostic.
648      SemaRef.Diags.setLastDiagnosticIgnored();
649      SemaRef.Diags.Clear();
650      Clear();
651      return;
652    }
653  }
654
655  // Emit the diagnostic.
656  if (!this->Emit())
657    return;
658
659  // If this is not a note, and we're in a template instantiation
660  // that is different from the last template instantiation where
661  // we emitted an error, print a template instantiation
662  // backtrace.
663  if (!DiagnosticIDs::isBuiltinNote(DiagID) &&
664      !SemaRef.ActiveTemplateInstantiations.empty() &&
665      SemaRef.ActiveTemplateInstantiations.back()
666        != SemaRef.LastTemplateInstantiationErrorContext) {
667    SemaRef.PrintInstantiationStack();
668    SemaRef.LastTemplateInstantiationErrorContext
669      = SemaRef.ActiveTemplateInstantiations.back();
670  }
671}
672
673Sema::SemaDiagnosticBuilder Sema::Diag(SourceLocation Loc, unsigned DiagID) {
674  DiagnosticBuilder DB = Diags.Report(Loc, DiagID);
675  return SemaDiagnosticBuilder(DB, *this, DiagID);
676}
677
678Sema::SemaDiagnosticBuilder
679Sema::Diag(SourceLocation Loc, const PartialDiagnostic& PD) {
680  SemaDiagnosticBuilder Builder(Diag(Loc, PD.getDiagID()));
681  PD.Emit(Builder);
682
683  return Builder;
684}
685
686/// \brief Looks through the macro-expansion chain for the given
687/// location, looking for a macro expansion with the given name.
688/// If one is found, returns true and sets the location to that
689/// expansion loc.
690bool Sema::findMacroSpelling(SourceLocation &locref, StringRef name) {
691  SourceLocation loc = locref;
692  if (!loc.isMacroID()) return false;
693
694  // There's no good way right now to look at the intermediate
695  // expansions, so just jump to the expansion location.
696  loc = getSourceManager().getExpansionLoc(loc);
697
698  // If that's written with the name, stop here.
699  SmallVector<char, 16> buffer;
700  if (getPreprocessor().getSpelling(loc, buffer) == name) {
701    locref = loc;
702    return true;
703  }
704  return false;
705}
706
707/// \brief Determines the active Scope associated with the given declaration
708/// context.
709///
710/// This routine maps a declaration context to the active Scope object that
711/// represents that declaration context in the parser. It is typically used
712/// from "scope-less" code (e.g., template instantiation, lazy creation of
713/// declarations) that injects a name for name-lookup purposes and, therefore,
714/// must update the Scope.
715///
716/// \returns The scope corresponding to the given declaraion context, or NULL
717/// if no such scope is open.
718Scope *Sema::getScopeForContext(DeclContext *Ctx) {
719
720  if (!Ctx)
721    return 0;
722
723  Ctx = Ctx->getPrimaryContext();
724  for (Scope *S = getCurScope(); S; S = S->getParent()) {
725    // Ignore scopes that cannot have declarations. This is important for
726    // out-of-line definitions of static class members.
727    if (S->getFlags() & (Scope::DeclScope | Scope::TemplateParamScope))
728      if (DeclContext *Entity = static_cast<DeclContext *> (S->getEntity()))
729        if (Ctx == Entity->getPrimaryContext())
730          return S;
731  }
732
733  return 0;
734}
735
736/// \brief Enter a new function scope
737void Sema::PushFunctionScope() {
738  if (FunctionScopes.size() == 1) {
739    // Use the "top" function scope rather than having to allocate
740    // memory for a new scope.
741    FunctionScopes.back()->Clear();
742    FunctionScopes.push_back(FunctionScopes.back());
743    return;
744  }
745
746  FunctionScopes.push_back(new FunctionScopeInfo(getDiagnostics()));
747}
748
749void Sema::PushBlockScope(Scope *BlockScope, BlockDecl *Block) {
750  FunctionScopes.push_back(new BlockScopeInfo(getDiagnostics(),
751                                              BlockScope, Block));
752}
753
754void Sema::PopFunctionOrBlockScope(const AnalysisBasedWarnings::Policy *WP,
755                                   const Decl *D, const BlockExpr *blkExpr) {
756  FunctionScopeInfo *Scope = FunctionScopes.pop_back_val();
757  assert(!FunctionScopes.empty() && "mismatched push/pop!");
758
759  // Issue any analysis-based warnings.
760  if (WP && D)
761    AnalysisWarnings.IssueWarnings(*WP, Scope, D, blkExpr);
762  else {
763    for (SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator
764         i = Scope->PossiblyUnreachableDiags.begin(),
765         e = Scope->PossiblyUnreachableDiags.end();
766         i != e; ++i) {
767      const sema::PossiblyUnreachableDiag &D = *i;
768      Diag(D.Loc, D.PD);
769    }
770  }
771
772  if (FunctionScopes.back() != Scope) {
773    delete Scope;
774  }
775}
776
777/// \brief Determine whether any errors occurred within this function/method/
778/// block.
779bool Sema::hasAnyUnrecoverableErrorsInThisFunction() const {
780  return getCurFunction()->ErrorTrap.hasUnrecoverableErrorOccurred();
781}
782
783BlockScopeInfo *Sema::getCurBlock() {
784  if (FunctionScopes.empty())
785    return 0;
786
787  return dyn_cast<BlockScopeInfo>(FunctionScopes.back());
788}
789
790// Pin this vtable to this file.
791ExternalSemaSource::~ExternalSemaSource() {}
792
793std::pair<ObjCMethodList, ObjCMethodList>
794ExternalSemaSource::ReadMethodPool(Selector Sel) {
795  return std::pair<ObjCMethodList, ObjCMethodList>();
796}
797
798void ExternalSemaSource::ReadKnownNamespaces(
799                           SmallVectorImpl<NamespaceDecl *> &Namespaces) {
800}
801
802void PrettyDeclStackTraceEntry::print(raw_ostream &OS) const {
803  SourceLocation Loc = this->Loc;
804  if (!Loc.isValid() && TheDecl) Loc = TheDecl->getLocation();
805  if (Loc.isValid()) {
806    Loc.print(OS, S.getSourceManager());
807    OS << ": ";
808  }
809  OS << Message;
810
811  if (TheDecl && isa<NamedDecl>(TheDecl)) {
812    std::string Name = cast<NamedDecl>(TheDecl)->getNameAsString();
813    if (!Name.empty())
814      OS << " '" << Name << '\'';
815  }
816
817  OS << '\n';
818}
819
820/// \brief Figure out if an expression could be turned into a call.
821///
822/// Use this when trying to recover from an error where the programmer may have
823/// written just the name of a function instead of actually calling it.
824///
825/// \param E - The expression to examine.
826/// \param ZeroArgCallReturnTy - If the expression can be turned into a call
827///  with no arguments, this parameter is set to the type returned by such a
828///  call; otherwise, it is set to an empty QualType.
829/// \param NonTemplateOverloads - If the expression is an overloaded function
830///  name, this parameter is populated with the decls of the various overloads.
831bool Sema::isExprCallable(const Expr &E, QualType &ZeroArgCallReturnTy,
832                          UnresolvedSetImpl &NonTemplateOverloads) {
833  ZeroArgCallReturnTy = QualType();
834  NonTemplateOverloads.clear();
835  if (const OverloadExpr *Overloads = dyn_cast<OverloadExpr>(&E)) {
836    for (OverloadExpr::decls_iterator it = Overloads->decls_begin(),
837         DeclsEnd = Overloads->decls_end(); it != DeclsEnd; ++it) {
838      // Our overload set may include TemplateDecls, which we'll ignore for our
839      // present purpose.
840      if (const FunctionDecl *OverloadDecl = dyn_cast<FunctionDecl>(*it)) {
841        NonTemplateOverloads.addDecl(*it);
842        if (OverloadDecl->getMinRequiredArguments() == 0)
843          ZeroArgCallReturnTy = OverloadDecl->getResultType();
844      }
845    }
846    return true;
847  }
848
849  if (const DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(&E)) {
850    if (const FunctionDecl *Fun = dyn_cast<FunctionDecl>(DeclRef->getDecl())) {
851      if (Fun->getMinRequiredArguments() == 0)
852        ZeroArgCallReturnTy = Fun->getResultType();
853      return true;
854    }
855  }
856
857  // We don't have an expression that's convenient to get a FunctionDecl from,
858  // but we can at least check if the type is "function of 0 arguments".
859  QualType ExprTy = E.getType();
860  const FunctionType *FunTy = NULL;
861  QualType PointeeTy = ExprTy->getPointeeType();
862  if (!PointeeTy.isNull())
863    FunTy = PointeeTy->getAs<FunctionType>();
864  if (!FunTy)
865    FunTy = ExprTy->getAs<FunctionType>();
866  if (!FunTy && ExprTy == Context.BoundMemberTy) {
867    // Look for the bound-member type.  If it's still overloaded, give up,
868    // although we probably should have fallen into the OverloadExpr case above
869    // if we actually have an overloaded bound member.
870    QualType BoundMemberTy = Expr::findBoundMemberType(&E);
871    if (!BoundMemberTy.isNull())
872      FunTy = BoundMemberTy->castAs<FunctionType>();
873  }
874
875  if (const FunctionProtoType *FPT =
876      dyn_cast_or_null<FunctionProtoType>(FunTy)) {
877    if (FPT->getNumArgs() == 0)
878      ZeroArgCallReturnTy = FunTy->getResultType();
879    return true;
880  }
881  return false;
882}
883
884/// \brief Give notes for a set of overloads.
885///
886/// A companion to isExprCallable. In cases when the name that the programmer
887/// wrote was an overloaded function, we may be able to make some guesses about
888/// plausible overloads based on their return types; such guesses can be handed
889/// off to this method to be emitted as notes.
890///
891/// \param Overloads - The overloads to note.
892/// \param FinalNoteLoc - If we've suppressed printing some overloads due to
893///  -fshow-overloads=best, this is the location to attach to the note about too
894///  many candidates. Typically this will be the location of the original
895///  ill-formed expression.
896void Sema::NoteOverloads(const UnresolvedSetImpl &Overloads,
897                         const SourceLocation FinalNoteLoc) {
898  int ShownOverloads = 0;
899  int SuppressedOverloads = 0;
900  for (UnresolvedSetImpl::iterator It = Overloads.begin(),
901       DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) {
902    // FIXME: Magic number for max shown overloads stolen from
903    // OverloadCandidateSet::NoteCandidates.
904    if (ShownOverloads >= 4 &&
905        Diags.getShowOverloads() == Diagnostic::Ovl_Best) {
906      ++SuppressedOverloads;
907      continue;
908    }
909    Diag(cast<FunctionDecl>(*It)->getSourceRange().getBegin(),
910         diag::note_member_ref_possible_intended_overload);
911    ++ShownOverloads;
912  }
913  if (SuppressedOverloads)
914    Diag(FinalNoteLoc, diag::note_ovl_too_many_candidates)
915        << SuppressedOverloads;
916}
917