Sema.cpp revision 344472ebeded2fca2ed5013b9e87f81d09bfa908 
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 "TargetAttributesSema.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/ASTDiagnostic.h"
19#include "clang/AST/DeclCXX.h"
20#include "clang/AST/DeclFriend.h"
21#include "clang/AST/DeclObjC.h"
22#include "clang/AST/Expr.h"
23#include "clang/AST/ExprCXX.h"
24#include "clang/AST/StmtCXX.h"
25#include "clang/Basic/FileManager.h"
26#include "clang/Basic/PartialDiagnostic.h"
27#include "clang/Basic/TargetInfo.h"
28#include "clang/Lex/HeaderSearch.h"
29#include "clang/Lex/Preprocessor.h"
30#include "clang/Sema/CXXFieldCollector.h"
31#include "clang/Sema/DelayedDiagnostic.h"
32#include "clang/Sema/ExternalSemaSource.h"
33#include "clang/Sema/MultiplexExternalSemaSource.h"
34#include "clang/Sema/ObjCMethodList.h"
35#include "clang/Sema/PrettyDeclStackTrace.h"
36#include "clang/Sema/Scope.h"
37#include "clang/Sema/ScopeInfo.h"
38#include "clang/Sema/SemaConsumer.h"
39#include "clang/Sema/TemplateDeduction.h"
40#include "llvm/ADT/APFloat.h"
41#include "llvm/ADT/DenseMap.h"
42#include "llvm/ADT/SmallSet.h"
43#include "llvm/Support/CrashRecoveryContext.h"
44using namespace clang;
45using namespace sema;
46
47PrintingPolicy Sema::getPrintingPolicy(const ASTContext &Context,
48                                       const Preprocessor &PP) {
49  PrintingPolicy Policy = Context.getPrintingPolicy();
50  Policy.Bool = Context.getLangOpts().Bool;
51  if (!Policy.Bool) {
52    if (const MacroInfo *
53          BoolMacro = PP.getMacroInfo(&Context.Idents.get("bool"))) {
54      Policy.Bool = BoolMacro->isObjectLike() &&
55        BoolMacro->getNumTokens() == 1 &&
56        BoolMacro->getReplacementToken(0).is(tok::kw__Bool);
57    }
58  }
59
60  return Policy;
61}
62
63void Sema::ActOnTranslationUnitScope(Scope *S) {
64  TUScope = S;
65  PushDeclContext(S, Context.getTranslationUnitDecl());
66
67  VAListTagName = PP.getIdentifierInfo("__va_list_tag");
68}
69
70Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
71           TranslationUnitKind TUKind,
72           CodeCompleteConsumer *CodeCompleter)
73  : TheTargetAttributesSema(0), ExternalSource(0),
74    isMultiplexExternalSource(false), FPFeatures(pp.getLangOpts()),
75    LangOpts(pp.getLangOpts()), PP(pp), Context(ctxt), Consumer(consumer),
76    Diags(PP.getDiagnostics()), SourceMgr(PP.getSourceManager()),
77    CollectStats(false), CodeCompleter(CodeCompleter),
78    CurContext(0), OriginalLexicalContext(0),
79    PackContext(0), MSStructPragmaOn(false), VisContext(0),
80    IsBuildingRecoveryCallExpr(false),
81    ExprNeedsCleanups(false), LateTemplateParser(0), OpaqueParser(0),
82    IdResolver(pp), StdInitializerList(0), CXXTypeInfoDecl(0), MSVCGuidDecl(0),
83    NSNumberDecl(0),
84    NSStringDecl(0), StringWithUTF8StringMethod(0),
85    NSArrayDecl(0), ArrayWithObjectsMethod(0),
86    NSDictionaryDecl(0), DictionaryWithObjectsMethod(0),
87    GlobalNewDeleteDeclared(false),
88    TUKind(TUKind),
89    NumSFINAEErrors(0), InFunctionDeclarator(0),
90    AccessCheckingSFINAE(false), InNonInstantiationSFINAEContext(false),
91    NonInstantiationEntries(0), ArgumentPackSubstitutionIndex(-1),
92    CurrentInstantiationScope(0), TyposCorrected(0),
93    AnalysisWarnings(*this), CurScope(0), Ident_super(0), Ident___float128(0)
94{
95  TUScope = 0;
96
97  LoadedExternalKnownNamespaces = false;
98  for (unsigned I = 0; I != NSAPI::NumNSNumberLiteralMethods; ++I)
99    NSNumberLiteralMethods[I] = 0;
100
101  if (getLangOpts().ObjC1)
102    NSAPIObj.reset(new NSAPI(Context));
103
104  if (getLangOpts().CPlusPlus)
105    FieldCollector.reset(new CXXFieldCollector());
106
107  // Tell diagnostics how to render things from the AST library.
108  PP.getDiagnostics().SetArgToStringFn(&FormatASTNodeDiagnosticArgument,
109                                       &Context);
110
111  ExprEvalContexts.push_back(
112        ExpressionEvaluationContextRecord(PotentiallyEvaluated, 0,
113                                          false, 0, false));
114
115  FunctionScopes.push_back(new FunctionScopeInfo(Diags));
116}
117
118void Sema::Initialize() {
119  // Tell the AST consumer about this Sema object.
120  Consumer.Initialize(Context);
121
122  // FIXME: Isn't this redundant with the initialization above?
123  if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
124    SC->InitializeSema(*this);
125
126  // Tell the external Sema source about this Sema object.
127  if (ExternalSemaSource *ExternalSema
128      = dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
129    ExternalSema->InitializeSema(*this);
130
131  // Initialize predefined 128-bit integer types, if needed.
132  if (PP.getTargetInfo().hasInt128Type()) {
133    // If either of the 128-bit integer types are unavailable to name lookup,
134    // define them now.
135    DeclarationName Int128 = &Context.Idents.get("__int128_t");
136    if (IdResolver.begin(Int128) == IdResolver.end())
137      PushOnScopeChains(Context.getInt128Decl(), TUScope);
138
139    DeclarationName UInt128 = &Context.Idents.get("__uint128_t");
140    if (IdResolver.begin(UInt128) == IdResolver.end())
141      PushOnScopeChains(Context.getUInt128Decl(), TUScope);
142  }
143
144
145  // Initialize predefined Objective-C types:
146  if (PP.getLangOpts().ObjC1) {
147    // If 'SEL' does not yet refer to any declarations, make it refer to the
148    // predefined 'SEL'.
149    DeclarationName SEL = &Context.Idents.get("SEL");
150    if (IdResolver.begin(SEL) == IdResolver.end())
151      PushOnScopeChains(Context.getObjCSelDecl(), TUScope);
152
153    // If 'id' does not yet refer to any declarations, make it refer to the
154    // predefined 'id'.
155    DeclarationName Id = &Context.Idents.get("id");
156    if (IdResolver.begin(Id) == IdResolver.end())
157      PushOnScopeChains(Context.getObjCIdDecl(), TUScope);
158
159    // Create the built-in typedef for 'Class'.
160    DeclarationName Class = &Context.Idents.get("Class");
161    if (IdResolver.begin(Class) == IdResolver.end())
162      PushOnScopeChains(Context.getObjCClassDecl(), TUScope);
163
164    // Create the built-in forward declaratino for 'Protocol'.
165    DeclarationName Protocol = &Context.Idents.get("Protocol");
166    if (IdResolver.begin(Protocol) == IdResolver.end())
167      PushOnScopeChains(Context.getObjCProtocolDecl(), TUScope);
168  }
169
170  DeclarationName BuiltinVaList = &Context.Idents.get("__builtin_va_list");
171  if (IdResolver.begin(BuiltinVaList) == IdResolver.end())
172    PushOnScopeChains(Context.getBuiltinVaListDecl(), TUScope);
173}
174
175Sema::~Sema() {
176  for (LateParsedTemplateMapT::iterator I = LateParsedTemplateMap.begin(),
177                                        E = LateParsedTemplateMap.end();
178       I != E; ++I)
179    delete I->second;
180  if (PackContext) FreePackedContext();
181  if (VisContext) FreeVisContext();
182  delete TheTargetAttributesSema;
183  MSStructPragmaOn = false;
184  // Kill all the active scopes.
185  for (unsigned I = 1, E = FunctionScopes.size(); I != E; ++I)
186    delete FunctionScopes[I];
187  if (FunctionScopes.size() == 1)
188    delete FunctionScopes[0];
189
190  // Tell the SemaConsumer to forget about us; we're going out of scope.
191  if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
192    SC->ForgetSema();
193
194  // Detach from the external Sema source.
195  if (ExternalSemaSource *ExternalSema
196        = dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
197    ExternalSema->ForgetSema();
198
199  // If Sema's ExternalSource is the multiplexer - we own it.
200  if (isMultiplexExternalSource)
201    delete ExternalSource;
202}
203
204/// makeUnavailableInSystemHeader - There is an error in the current
205/// context.  If we're still in a system header, and we can plausibly
206/// make the relevant declaration unavailable instead of erroring, do
207/// so and return true.
208bool Sema::makeUnavailableInSystemHeader(SourceLocation loc,
209                                         StringRef msg) {
210  // If we're not in a function, it's an error.
211  FunctionDecl *fn = dyn_cast<FunctionDecl>(CurContext);
212  if (!fn) return false;
213
214  // If we're in template instantiation, it's an error.
215  if (!ActiveTemplateInstantiations.empty())
216    return false;
217
218  // If that function's not in a system header, it's an error.
219  if (!Context.getSourceManager().isInSystemHeader(loc))
220    return false;
221
222  // If the function is already unavailable, it's not an error.
223  if (fn->hasAttr<UnavailableAttr>()) return true;
224
225  fn->addAttr(new (Context) UnavailableAttr(loc, Context, msg));
226  return true;
227}
228
229ASTMutationListener *Sema::getASTMutationListener() const {
230  return getASTConsumer().GetASTMutationListener();
231}
232
233///\brief Registers an external source. If an external source already exists,
234/// creates a multiplex external source and appends to it.
235///
236///\param[in] E - A non-null external sema source.
237///
238void Sema::addExternalSource(ExternalSemaSource *E) {
239  assert(E && "Cannot use with NULL ptr");
240
241  if (!ExternalSource) {
242    ExternalSource = E;
243    return;
244  }
245
246  if (isMultiplexExternalSource)
247    static_cast<MultiplexExternalSemaSource*>(ExternalSource)->addSource(*E);
248  else {
249    ExternalSource = new MultiplexExternalSemaSource(*ExternalSource, *E);
250    isMultiplexExternalSource = true;
251  }
252}
253
254/// \brief Print out statistics about the semantic analysis.
255void Sema::PrintStats() const {
256  llvm::errs() << "\n*** Semantic Analysis Stats:\n";
257  llvm::errs() << NumSFINAEErrors << " SFINAE diagnostics trapped.\n";
258
259  BumpAlloc.PrintStats();
260  AnalysisWarnings.PrintStats();
261}
262
263/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast.
264/// If there is already an implicit cast, merge into the existing one.
265/// The result is of the given category.
266ExprResult Sema::ImpCastExprToType(Expr *E, QualType Ty,
267                                   CastKind Kind, ExprValueKind VK,
268                                   const CXXCastPath *BasePath,
269                                   CheckedConversionKind CCK) {
270#ifndef NDEBUG
271  if (VK == VK_RValue && !E->isRValue()) {
272    switch (Kind) {
273    default:
274      assert(0 && "can't implicitly cast lvalue to rvalue with this cast kind");
275    case CK_LValueToRValue:
276    case CK_ArrayToPointerDecay:
277    case CK_FunctionToPointerDecay:
278    case CK_ToVoid:
279      break;
280    }
281  }
282  assert((VK == VK_RValue || !E->isRValue()) && "can't cast rvalue to lvalue");
283#endif
284
285  QualType ExprTy = Context.getCanonicalType(E->getType());
286  QualType TypeTy = Context.getCanonicalType(Ty);
287
288  if (ExprTy == TypeTy)
289    return Owned(E);
290
291  // If this is a derived-to-base cast to a through a virtual base, we
292  // need a vtable.
293  if (Kind == CK_DerivedToBase &&
294      BasePathInvolvesVirtualBase(*BasePath)) {
295    QualType T = E->getType();
296    if (const PointerType *Pointer = T->getAs<PointerType>())
297      T = Pointer->getPointeeType();
298    if (const RecordType *RecordTy = T->getAs<RecordType>())
299      MarkVTableUsed(E->getLocStart(),
300                     cast<CXXRecordDecl>(RecordTy->getDecl()));
301  }
302
303  if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(E)) {
304    if (ImpCast->getCastKind() == Kind && (!BasePath || BasePath->empty())) {
305      ImpCast->setType(Ty);
306      ImpCast->setValueKind(VK);
307      return Owned(E);
308    }
309  }
310
311  return Owned(ImplicitCastExpr::Create(Context, Ty, Kind, E, BasePath, VK));
312}
313
314/// ScalarTypeToBooleanCastKind - Returns the cast kind corresponding
315/// to the conversion from scalar type ScalarTy to the Boolean type.
316CastKind Sema::ScalarTypeToBooleanCastKind(QualType ScalarTy) {
317  switch (ScalarTy->getScalarTypeKind()) {
318  case Type::STK_Bool: return CK_NoOp;
319  case Type::STK_CPointer: return CK_PointerToBoolean;
320  case Type::STK_BlockPointer: return CK_PointerToBoolean;
321  case Type::STK_ObjCObjectPointer: return CK_PointerToBoolean;
322  case Type::STK_MemberPointer: return CK_MemberPointerToBoolean;
323  case Type::STK_Integral: return CK_IntegralToBoolean;
324  case Type::STK_Floating: return CK_FloatingToBoolean;
325  case Type::STK_IntegralComplex: return CK_IntegralComplexToBoolean;
326  case Type::STK_FloatingComplex: return CK_FloatingComplexToBoolean;
327  }
328  return CK_Invalid;
329}
330
331/// \brief Used to prune the decls of Sema's UnusedFileScopedDecls vector.
332static bool ShouldRemoveFromUnused(Sema *SemaRef, const DeclaratorDecl *D) {
333  if (D->getMostRecentDecl()->isUsed())
334    return true;
335
336  if (D->isExternallyVisible())
337    return true;
338
339  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
340    // UnusedFileScopedDecls stores the first declaration.
341    // The declaration may have become definition so check again.
342    const FunctionDecl *DeclToCheck;
343    if (FD->hasBody(DeclToCheck))
344      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
345
346    // Later redecls may add new information resulting in not having to warn,
347    // so check again.
348    DeclToCheck = FD->getMostRecentDecl();
349    if (DeclToCheck != FD)
350      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
351  }
352
353  if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
354    // UnusedFileScopedDecls stores the first declaration.
355    // The declaration may have become definition so check again.
356    const VarDecl *DeclToCheck = VD->getDefinition();
357    if (DeclToCheck)
358      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
359
360    // Later redecls may add new information resulting in not having to warn,
361    // so check again.
362    DeclToCheck = VD->getMostRecentDecl();
363    if (DeclToCheck != VD)
364      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
365  }
366
367  return false;
368}
369
370namespace {
371  struct SortUndefinedButUsed {
372    const SourceManager &SM;
373    explicit SortUndefinedButUsed(SourceManager &SM) : SM(SM) {}
374
375    bool operator()(const std::pair<NamedDecl *, SourceLocation> &l,
376                    const std::pair<NamedDecl *, SourceLocation> &r) const {
377      if (l.second.isValid() && !r.second.isValid())
378        return true;
379      if (!l.second.isValid() && r.second.isValid())
380        return false;
381      if (l.second != r.second)
382        return SM.isBeforeInTranslationUnit(l.second, r.second);
383      return SM.isBeforeInTranslationUnit(l.first->getLocation(),
384                                          r.first->getLocation());
385    }
386  };
387}
388
389/// Obtains a sorted list of functions that are undefined but ODR-used.
390void Sema::getUndefinedButUsed(
391    SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> > &Undefined) {
392  for (llvm::DenseMap<NamedDecl *, SourceLocation>::iterator
393         I = UndefinedButUsed.begin(), E = UndefinedButUsed.end();
394       I != E; ++I) {
395    NamedDecl *ND = I->first;
396
397    // Ignore attributes that have become invalid.
398    if (ND->isInvalidDecl()) continue;
399
400    // __attribute__((weakref)) is basically a definition.
401    if (ND->hasAttr<WeakRefAttr>()) continue;
402
403    if (FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
404      if (FD->isDefined())
405        continue;
406      if (FD->isExternallyVisible() &&
407          !FD->getMostRecentDecl()->isInlined())
408        continue;
409    } else {
410      if (cast<VarDecl>(ND)->hasDefinition() != VarDecl::DeclarationOnly)
411        continue;
412      if (ND->isExternallyVisible())
413        continue;
414    }
415
416    Undefined.push_back(std::make_pair(ND, I->second));
417  }
418
419  // Sort (in order of use site) so that we're not dependent on the iteration
420  // order through an llvm::DenseMap.
421  std::sort(Undefined.begin(), Undefined.end(),
422            SortUndefinedButUsed(Context.getSourceManager()));
423}
424
425/// checkUndefinedButUsed - Check for undefined objects with internal linkage
426/// or that are inline.
427static void checkUndefinedButUsed(Sema &S) {
428  if (S.UndefinedButUsed.empty()) return;
429
430  // Collect all the still-undefined entities with internal linkage.
431  SmallVector<std::pair<NamedDecl *, SourceLocation>, 16> Undefined;
432  S.getUndefinedButUsed(Undefined);
433  if (Undefined.empty()) return;
434
435  for (SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> >::iterator
436         I = Undefined.begin(), E = Undefined.end(); I != E; ++I) {
437    NamedDecl *ND = I->first;
438
439    if (!ND->isExternallyVisible()) {
440      S.Diag(ND->getLocation(), diag::warn_undefined_internal)
441        << isa<VarDecl>(ND) << ND;
442    } else {
443      assert(cast<FunctionDecl>(ND)->getMostRecentDecl()->isInlined() &&
444             "used object requires definition but isn't inline or internal?");
445      S.Diag(ND->getLocation(), diag::warn_undefined_inline) << ND;
446    }
447    if (I->second.isValid())
448      S.Diag(I->second, diag::note_used_here);
449  }
450}
451
452void Sema::LoadExternalWeakUndeclaredIdentifiers() {
453  if (!ExternalSource)
454    return;
455
456  SmallVector<std::pair<IdentifierInfo *, WeakInfo>, 4> WeakIDs;
457  ExternalSource->ReadWeakUndeclaredIdentifiers(WeakIDs);
458  for (unsigned I = 0, N = WeakIDs.size(); I != N; ++I) {
459    llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator Pos
460      = WeakUndeclaredIdentifiers.find(WeakIDs[I].first);
461    if (Pos != WeakUndeclaredIdentifiers.end())
462      continue;
463
464    WeakUndeclaredIdentifiers.insert(WeakIDs[I]);
465  }
466}
467
468
469typedef llvm::DenseMap<const CXXRecordDecl*, bool> RecordCompleteMap;
470
471/// \brief Returns true, if all methods and nested classes of the given
472/// CXXRecordDecl are defined in this translation unit.
473///
474/// Should only be called from ActOnEndOfTranslationUnit so that all
475/// definitions are actually read.
476static bool MethodsAndNestedClassesComplete(const CXXRecordDecl *RD,
477                                            RecordCompleteMap &MNCComplete) {
478  RecordCompleteMap::iterator Cache = MNCComplete.find(RD);
479  if (Cache != MNCComplete.end())
480    return Cache->second;
481  if (!RD->isCompleteDefinition())
482    return false;
483  bool Complete = true;
484  for (DeclContext::decl_iterator I = RD->decls_begin(),
485                                  E = RD->decls_end();
486       I != E && Complete; ++I) {
487    if (const CXXMethodDecl *M = dyn_cast<CXXMethodDecl>(*I))
488      Complete = M->isDefined() || (M->isPure() && !isa<CXXDestructorDecl>(M));
489    else if (const FunctionTemplateDecl *F = dyn_cast<FunctionTemplateDecl>(*I))
490      Complete = F->getTemplatedDecl()->isDefined();
491    else if (const CXXRecordDecl *R = dyn_cast<CXXRecordDecl>(*I)) {
492      if (R->isInjectedClassName())
493        continue;
494      if (R->hasDefinition())
495        Complete = MethodsAndNestedClassesComplete(R->getDefinition(),
496                                                   MNCComplete);
497      else
498        Complete = false;
499    }
500  }
501  MNCComplete[RD] = Complete;
502  return Complete;
503}
504
505/// \brief Returns true, if the given CXXRecordDecl is fully defined in this
506/// translation unit, i.e. all methods are defined or pure virtual and all
507/// friends, friend functions and nested classes are fully defined in this
508/// translation unit.
509///
510/// Should only be called from ActOnEndOfTranslationUnit so that all
511/// definitions are actually read.
512static bool IsRecordFullyDefined(const CXXRecordDecl *RD,
513                                 RecordCompleteMap &RecordsComplete,
514                                 RecordCompleteMap &MNCComplete) {
515  RecordCompleteMap::iterator Cache = RecordsComplete.find(RD);
516  if (Cache != RecordsComplete.end())
517    return Cache->second;
518  bool Complete = MethodsAndNestedClassesComplete(RD, MNCComplete);
519  for (CXXRecordDecl::friend_iterator I = RD->friend_begin(),
520                                      E = RD->friend_end();
521       I != E && Complete; ++I) {
522    // Check if friend classes and methods are complete.
523    if (TypeSourceInfo *TSI = (*I)->getFriendType()) {
524      // Friend classes are available as the TypeSourceInfo of the FriendDecl.
525      if (CXXRecordDecl *FriendD = TSI->getType()->getAsCXXRecordDecl())
526        Complete = MethodsAndNestedClassesComplete(FriendD, MNCComplete);
527      else
528        Complete = false;
529    } else {
530      // Friend functions are available through the NamedDecl of FriendDecl.
531      if (const FunctionDecl *FD =
532          dyn_cast<FunctionDecl>((*I)->getFriendDecl()))
533        Complete = FD->isDefined();
534      else
535        // This is a template friend, give up.
536        Complete = false;
537    }
538  }
539  RecordsComplete[RD] = Complete;
540  return Complete;
541}
542
543/// ActOnEndOfTranslationUnit - This is called at the very end of the
544/// translation unit when EOF is reached and all but the top-level scope is
545/// popped.
546void Sema::ActOnEndOfTranslationUnit() {
547  assert(DelayedDiagnostics.getCurrentPool() == NULL
548         && "reached end of translation unit with a pool attached?");
549
550  // If code completion is enabled, don't perform any end-of-translation-unit
551  // work.
552  if (PP.isCodeCompletionEnabled())
553    return;
554
555  // Complete translation units and modules define vtables and perform implicit
556  // instantiations. PCH files do not.
557  if (TUKind != TU_Prefix) {
558    DiagnoseUseOfUnimplementedSelectors();
559
560    // If any dynamic classes have their key function defined within
561    // this translation unit, then those vtables are considered "used" and must
562    // be emitted.
563    for (DynamicClassesType::iterator I = DynamicClasses.begin(ExternalSource),
564                                      E = DynamicClasses.end();
565         I != E; ++I) {
566      assert(!(*I)->isDependentType() &&
567             "Should not see dependent types here!");
568      if (const CXXMethodDecl *KeyFunction = Context.getCurrentKeyFunction(*I)) {
569        const FunctionDecl *Definition = 0;
570        if (KeyFunction->hasBody(Definition))
571          MarkVTableUsed(Definition->getLocation(), *I, true);
572      }
573    }
574
575    // If DefinedUsedVTables ends up marking any virtual member functions it
576    // might lead to more pending template instantiations, which we then need
577    // to instantiate.
578    DefineUsedVTables();
579
580    // C++: Perform implicit template instantiations.
581    //
582    // FIXME: When we perform these implicit instantiations, we do not
583    // carefully keep track of the point of instantiation (C++ [temp.point]).
584    // This means that name lookup that occurs within the template
585    // instantiation will always happen at the end of the translation unit,
586    // so it will find some names that are not required to be found. This is
587    // valid, but we could do better by diagnosing if an instantiation uses a
588    // name that was not visible at its first point of instantiation.
589    PerformPendingInstantiations();
590  }
591
592  // Remove file scoped decls that turned out to be used.
593  UnusedFileScopedDecls.erase(
594      std::remove_if(UnusedFileScopedDecls.begin(0, true),
595                     UnusedFileScopedDecls.end(),
596                     std::bind1st(std::ptr_fun(ShouldRemoveFromUnused), this)),
597      UnusedFileScopedDecls.end());
598
599  if (TUKind == TU_Prefix) {
600    // Translation unit prefixes don't need any of the checking below.
601    TUScope = 0;
602    return;
603  }
604
605  // Check for #pragma weak identifiers that were never declared
606  // FIXME: This will cause diagnostics to be emitted in a non-determinstic
607  // order!  Iterating over a densemap like this is bad.
608  LoadExternalWeakUndeclaredIdentifiers();
609  for (llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator
610       I = WeakUndeclaredIdentifiers.begin(),
611       E = WeakUndeclaredIdentifiers.end(); I != E; ++I) {
612    if (I->second.getUsed()) continue;
613
614    Diag(I->second.getLocation(), diag::warn_weak_identifier_undeclared)
615      << I->first;
616  }
617
618  if (LangOpts.CPlusPlus11 &&
619      Diags.getDiagnosticLevel(diag::warn_delegating_ctor_cycle,
620                               SourceLocation())
621        != DiagnosticsEngine::Ignored)
622    CheckDelegatingCtorCycles();
623
624  if (TUKind == TU_Module) {
625    // If we are building a module, resolve all of the exported declarations
626    // now.
627    if (Module *CurrentModule = PP.getCurrentModule()) {
628      ModuleMap &ModMap = PP.getHeaderSearchInfo().getModuleMap();
629
630      SmallVector<Module *, 2> Stack;
631      Stack.push_back(CurrentModule);
632      while (!Stack.empty()) {
633        Module *Mod = Stack.pop_back_val();
634
635        // Resolve the exported declarations and conflicts.
636        // FIXME: Actually complain, once we figure out how to teach the
637        // diagnostic client to deal with complaints in the module map at this
638        // point.
639        ModMap.resolveExports(Mod, /*Complain=*/false);
640        ModMap.resolveConflicts(Mod, /*Complain=*/false);
641
642        // Queue the submodules, so their exports will also be resolved.
643        for (Module::submodule_iterator Sub = Mod->submodule_begin(),
644                                     SubEnd = Mod->submodule_end();
645             Sub != SubEnd; ++Sub) {
646          Stack.push_back(*Sub);
647        }
648      }
649    }
650
651    // Modules don't need any of the checking below.
652    TUScope = 0;
653    return;
654  }
655
656  // C99 6.9.2p2:
657  //   A declaration of an identifier for an object that has file
658  //   scope without an initializer, and without a storage-class
659  //   specifier or with the storage-class specifier static,
660  //   constitutes a tentative definition. If a translation unit
661  //   contains one or more tentative definitions for an identifier,
662  //   and the translation unit contains no external definition for
663  //   that identifier, then the behavior is exactly as if the
664  //   translation unit contains a file scope declaration of that
665  //   identifier, with the composite type as of the end of the
666  //   translation unit, with an initializer equal to 0.
667  llvm::SmallSet<VarDecl *, 32> Seen;
668  for (TentativeDefinitionsType::iterator
669            T = TentativeDefinitions.begin(ExternalSource),
670         TEnd = TentativeDefinitions.end();
671       T != TEnd; ++T)
672  {
673    VarDecl *VD = (*T)->getActingDefinition();
674
675    // If the tentative definition was completed, getActingDefinition() returns
676    // null. If we've already seen this variable before, insert()'s second
677    // return value is false.
678    if (VD == 0 || VD->isInvalidDecl() || !Seen.insert(VD))
679      continue;
680
681    if (const IncompleteArrayType *ArrayT
682        = Context.getAsIncompleteArrayType(VD->getType())) {
683      // Set the length of the array to 1 (C99 6.9.2p5).
684      Diag(VD->getLocation(), diag::warn_tentative_incomplete_array);
685      llvm::APInt One(Context.getTypeSize(Context.getSizeType()), true);
686      QualType T = Context.getConstantArrayType(ArrayT->getElementType(),
687                                                One, ArrayType::Normal, 0);
688      VD->setType(T);
689    } else if (RequireCompleteType(VD->getLocation(), VD->getType(),
690                                   diag::err_tentative_def_incomplete_type))
691      VD->setInvalidDecl();
692
693    CheckCompleteVariableDeclaration(VD);
694
695    // Notify the consumer that we've completed a tentative definition.
696    if (!VD->isInvalidDecl())
697      Consumer.CompleteTentativeDefinition(VD);
698
699  }
700
701  // If there were errors, disable 'unused' warnings since they will mostly be
702  // noise.
703  if (!Diags.hasErrorOccurred()) {
704    // Output warning for unused file scoped decls.
705    for (UnusedFileScopedDeclsType::iterator
706           I = UnusedFileScopedDecls.begin(ExternalSource),
707           E = UnusedFileScopedDecls.end(); I != E; ++I) {
708      if (ShouldRemoveFromUnused(this, *I))
709        continue;
710
711      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) {
712        const FunctionDecl *DiagD;
713        if (!FD->hasBody(DiagD))
714          DiagD = FD;
715        if (DiagD->isDeleted())
716          continue; // Deleted functions are supposed to be unused.
717        if (DiagD->isReferenced()) {
718          if (isa<CXXMethodDecl>(DiagD))
719            Diag(DiagD->getLocation(), diag::warn_unneeded_member_function)
720                  << DiagD->getDeclName();
721          else {
722            if (FD->getStorageClass() == SC_Static &&
723                !FD->isInlineSpecified() &&
724                !SourceMgr.isInMainFile(
725                   SourceMgr.getExpansionLoc(FD->getLocation())))
726              Diag(DiagD->getLocation(), diag::warn_unneeded_static_internal_decl)
727                << DiagD->getDeclName();
728            else
729              Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
730                   << /*function*/0 << DiagD->getDeclName();
731          }
732        } else {
733          Diag(DiagD->getLocation(),
734               isa<CXXMethodDecl>(DiagD) ? diag::warn_unused_member_function
735                                         : diag::warn_unused_function)
736                << DiagD->getDeclName();
737        }
738      } else {
739        const VarDecl *DiagD = cast<VarDecl>(*I)->getDefinition();
740        if (!DiagD)
741          DiagD = cast<VarDecl>(*I);
742        if (DiagD->isReferenced()) {
743          Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
744                << /*variable*/1 << DiagD->getDeclName();
745        } else if (SourceMgr.isInMainFile(DiagD->getLocation())) {
746          // If the declaration is in a header which is included into multiple
747          // TUs, it will declare one variable per TU, and one of the other
748          // variables may be used. So, only warn if the declaration is in the
749          // main file.
750          Diag(DiagD->getLocation(), diag::warn_unused_variable)
751              << DiagD->getDeclName();
752        }
753      }
754    }
755
756    if (ExternalSource)
757      ExternalSource->ReadUndefinedButUsed(UndefinedButUsed);
758    checkUndefinedButUsed(*this);
759  }
760
761  if (Diags.getDiagnosticLevel(diag::warn_unused_private_field,
762                               SourceLocation())
763        != DiagnosticsEngine::Ignored) {
764    RecordCompleteMap RecordsComplete;
765    RecordCompleteMap MNCComplete;
766    for (NamedDeclSetType::iterator I = UnusedPrivateFields.begin(),
767         E = UnusedPrivateFields.end(); I != E; ++I) {
768      const NamedDecl *D = *I;
769      const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D->getDeclContext());
770      if (RD && !RD->isUnion() &&
771          IsRecordFullyDefined(RD, RecordsComplete, MNCComplete)) {
772        Diag(D->getLocation(), diag::warn_unused_private_field)
773              << D->getDeclName();
774      }
775    }
776  }
777
778  // Check we've noticed that we're no longer parsing the initializer for every
779  // variable. If we miss cases, then at best we have a performance issue and
780  // at worst a rejects-valid bug.
781  assert(ParsingInitForAutoVars.empty() &&
782         "Didn't unmark var as having its initializer parsed");
783
784  TUScope = 0;
785}
786
787
788//===----------------------------------------------------------------------===//
789// Helper functions.
790//===----------------------------------------------------------------------===//
791
792DeclContext *Sema::getFunctionLevelDeclContext() {
793  DeclContext *DC = CurContext;
794
795  while (true) {
796    if (isa<BlockDecl>(DC) || isa<EnumDecl>(DC) || isa<CapturedDecl>(DC)) {
797      DC = DC->getParent();
798    } else if (isa<CXXMethodDecl>(DC) &&
799               cast<CXXMethodDecl>(DC)->getOverloadedOperator() == OO_Call &&
800               cast<CXXRecordDecl>(DC->getParent())->isLambda()) {
801      DC = DC->getParent()->getParent();
802    }
803    else break;
804  }
805
806  return DC;
807}
808
809/// getCurFunctionDecl - If inside of a function body, this returns a pointer
810/// to the function decl for the function being parsed.  If we're currently
811/// in a 'block', this returns the containing context.
812FunctionDecl *Sema::getCurFunctionDecl() {
813  DeclContext *DC = getFunctionLevelDeclContext();
814  return dyn_cast<FunctionDecl>(DC);
815}
816
817ObjCMethodDecl *Sema::getCurMethodDecl() {
818  DeclContext *DC = getFunctionLevelDeclContext();
819  while (isa<RecordDecl>(DC))
820    DC = DC->getParent();
821  return dyn_cast<ObjCMethodDecl>(DC);
822}
823
824NamedDecl *Sema::getCurFunctionOrMethodDecl() {
825  DeclContext *DC = getFunctionLevelDeclContext();
826  if (isa<ObjCMethodDecl>(DC) || isa<FunctionDecl>(DC))
827    return cast<NamedDecl>(DC);
828  return 0;
829}
830
831void Sema::EmitCurrentDiagnostic(unsigned DiagID) {
832  // FIXME: It doesn't make sense to me that DiagID is an incoming argument here
833  // and yet we also use the current diag ID on the DiagnosticsEngine. This has
834  // been made more painfully obvious by the refactor that introduced this
835  // function, but it is possible that the incoming argument can be
836  // eliminnated. If it truly cannot be (for example, there is some reentrancy
837  // issue I am not seeing yet), then there should at least be a clarifying
838  // comment somewhere.
839  if (Optional<TemplateDeductionInfo*> Info = isSFINAEContext()) {
840    switch (DiagnosticIDs::getDiagnosticSFINAEResponse(
841              Diags.getCurrentDiagID())) {
842    case DiagnosticIDs::SFINAE_Report:
843      // We'll report the diagnostic below.
844      break;
845
846    case DiagnosticIDs::SFINAE_SubstitutionFailure:
847      // Count this failure so that we know that template argument deduction
848      // has failed.
849      ++NumSFINAEErrors;
850
851      // Make a copy of this suppressed diagnostic and store it with the
852      // template-deduction information.
853      if (*Info && !(*Info)->hasSFINAEDiagnostic()) {
854        Diagnostic DiagInfo(&Diags);
855        (*Info)->addSFINAEDiagnostic(DiagInfo.getLocation(),
856                       PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
857      }
858
859      Diags.setLastDiagnosticIgnored();
860      Diags.Clear();
861      return;
862
863    case DiagnosticIDs::SFINAE_AccessControl: {
864      // Per C++ Core Issue 1170, access control is part of SFINAE.
865      // Additionally, the AccessCheckingSFINAE flag can be used to temporarily
866      // make access control a part of SFINAE for the purposes of checking
867      // type traits.
868      if (!AccessCheckingSFINAE && !getLangOpts().CPlusPlus11)
869        break;
870
871      SourceLocation Loc = Diags.getCurrentDiagLoc();
872
873      // Suppress this diagnostic.
874      ++NumSFINAEErrors;
875
876      // Make a copy of this suppressed diagnostic and store it with the
877      // template-deduction information.
878      if (*Info && !(*Info)->hasSFINAEDiagnostic()) {
879        Diagnostic DiagInfo(&Diags);
880        (*Info)->addSFINAEDiagnostic(DiagInfo.getLocation(),
881                       PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
882      }
883
884      Diags.setLastDiagnosticIgnored();
885      Diags.Clear();
886
887      // Now the diagnostic state is clear, produce a C++98 compatibility
888      // warning.
889      Diag(Loc, diag::warn_cxx98_compat_sfinae_access_control);
890
891      // The last diagnostic which Sema produced was ignored. Suppress any
892      // notes attached to it.
893      Diags.setLastDiagnosticIgnored();
894      return;
895    }
896
897    case DiagnosticIDs::SFINAE_Suppress:
898      // Make a copy of this suppressed diagnostic and store it with the
899      // template-deduction information;
900      if (*Info) {
901        Diagnostic DiagInfo(&Diags);
902        (*Info)->addSuppressedDiagnostic(DiagInfo.getLocation(),
903                       PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
904      }
905
906      // Suppress this diagnostic.
907      Diags.setLastDiagnosticIgnored();
908      Diags.Clear();
909      return;
910    }
911  }
912
913  // Set up the context's printing policy based on our current state.
914  Context.setPrintingPolicy(getPrintingPolicy());
915
916  // Emit the diagnostic.
917  if (!Diags.EmitCurrentDiagnostic())
918    return;
919
920  // If this is not a note, and we're in a template instantiation
921  // that is different from the last template instantiation where
922  // we emitted an error, print a template instantiation
923  // backtrace.
924  if (!DiagnosticIDs::isBuiltinNote(DiagID) &&
925      !ActiveTemplateInstantiations.empty() &&
926      ActiveTemplateInstantiations.back()
927        != LastTemplateInstantiationErrorContext) {
928    PrintInstantiationStack();
929    LastTemplateInstantiationErrorContext = ActiveTemplateInstantiations.back();
930  }
931}
932
933Sema::SemaDiagnosticBuilder
934Sema::Diag(SourceLocation Loc, const PartialDiagnostic& PD) {
935  SemaDiagnosticBuilder Builder(Diag(Loc, PD.getDiagID()));
936  PD.Emit(Builder);
937
938  return Builder;
939}
940
941/// \brief Looks through the macro-expansion chain for the given
942/// location, looking for a macro expansion with the given name.
943/// If one is found, returns true and sets the location to that
944/// expansion loc.
945bool Sema::findMacroSpelling(SourceLocation &locref, StringRef name) {
946  SourceLocation loc = locref;
947  if (!loc.isMacroID()) return false;
948
949  // There's no good way right now to look at the intermediate
950  // expansions, so just jump to the expansion location.
951  loc = getSourceManager().getExpansionLoc(loc);
952
953  // If that's written with the name, stop here.
954  SmallVector<char, 16> buffer;
955  if (getPreprocessor().getSpelling(loc, buffer) == name) {
956    locref = loc;
957    return true;
958  }
959  return false;
960}
961
962/// \brief Determines the active Scope associated with the given declaration
963/// context.
964///
965/// This routine maps a declaration context to the active Scope object that
966/// represents that declaration context in the parser. It is typically used
967/// from "scope-less" code (e.g., template instantiation, lazy creation of
968/// declarations) that injects a name for name-lookup purposes and, therefore,
969/// must update the Scope.
970///
971/// \returns The scope corresponding to the given declaraion context, or NULL
972/// if no such scope is open.
973Scope *Sema::getScopeForContext(DeclContext *Ctx) {
974
975  if (!Ctx)
976    return 0;
977
978  Ctx = Ctx->getPrimaryContext();
979  for (Scope *S = getCurScope(); S; S = S->getParent()) {
980    // Ignore scopes that cannot have declarations. This is important for
981    // out-of-line definitions of static class members.
982    if (S->getFlags() & (Scope::DeclScope | Scope::TemplateParamScope))
983      if (DeclContext *Entity = static_cast<DeclContext *> (S->getEntity()))
984        if (Ctx == Entity->getPrimaryContext())
985          return S;
986  }
987
988  return 0;
989}
990
991/// \brief Enter a new function scope
992void Sema::PushFunctionScope() {
993  if (FunctionScopes.size() == 1) {
994    // Use the "top" function scope rather than having to allocate
995    // memory for a new scope.
996    FunctionScopes.back()->Clear();
997    FunctionScopes.push_back(FunctionScopes.back());
998    return;
999  }
1000
1001  FunctionScopes.push_back(new FunctionScopeInfo(getDiagnostics()));
1002}
1003
1004void Sema::PushBlockScope(Scope *BlockScope, BlockDecl *Block) {
1005  FunctionScopes.push_back(new BlockScopeInfo(getDiagnostics(),
1006                                              BlockScope, Block));
1007}
1008
1009void Sema::PushLambdaScope(CXXRecordDecl *Lambda,
1010                           CXXMethodDecl *CallOperator) {
1011  FunctionScopes.push_back(new LambdaScopeInfo(getDiagnostics(), Lambda,
1012                                               CallOperator));
1013}
1014
1015void Sema::PopFunctionScopeInfo(const AnalysisBasedWarnings::Policy *WP,
1016                                const Decl *D, const BlockExpr *blkExpr) {
1017  FunctionScopeInfo *Scope = FunctionScopes.pop_back_val();
1018  assert(!FunctionScopes.empty() && "mismatched push/pop!");
1019
1020  // Issue any analysis-based warnings.
1021  if (WP && D)
1022    AnalysisWarnings.IssueWarnings(*WP, Scope, D, blkExpr);
1023  else {
1024    for (SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator
1025         i = Scope->PossiblyUnreachableDiags.begin(),
1026         e = Scope->PossiblyUnreachableDiags.end();
1027         i != e; ++i) {
1028      const sema::PossiblyUnreachableDiag &D = *i;
1029      Diag(D.Loc, D.PD);
1030    }
1031  }
1032
1033  if (FunctionScopes.back() != Scope) {
1034    delete Scope;
1035  }
1036}
1037
1038void Sema::PushCompoundScope() {
1039  getCurFunction()->CompoundScopes.push_back(CompoundScopeInfo());
1040}
1041
1042void Sema::PopCompoundScope() {
1043  FunctionScopeInfo *CurFunction = getCurFunction();
1044  assert(!CurFunction->CompoundScopes.empty() && "mismatched push/pop");
1045
1046  CurFunction->CompoundScopes.pop_back();
1047}
1048
1049/// \brief Determine whether any errors occurred within this function/method/
1050/// block.
1051bool Sema::hasAnyUnrecoverableErrorsInThisFunction() const {
1052  return getCurFunction()->ErrorTrap.hasUnrecoverableErrorOccurred();
1053}
1054
1055BlockScopeInfo *Sema::getCurBlock() {
1056  if (FunctionScopes.empty())
1057    return 0;
1058
1059  return dyn_cast<BlockScopeInfo>(FunctionScopes.back());
1060}
1061
1062LambdaScopeInfo *Sema::getCurLambda() {
1063  if (FunctionScopes.empty())
1064    return 0;
1065
1066  return dyn_cast<LambdaScopeInfo>(FunctionScopes.back());
1067}
1068
1069void Sema::ActOnComment(SourceRange Comment) {
1070  if (!LangOpts.RetainCommentsFromSystemHeaders &&
1071      SourceMgr.isInSystemHeader(Comment.getBegin()))
1072    return;
1073  RawComment RC(SourceMgr, Comment, false,
1074                LangOpts.CommentOpts.ParseAllComments);
1075  if (RC.isAlmostTrailingComment()) {
1076    SourceRange MagicMarkerRange(Comment.getBegin(),
1077                                 Comment.getBegin().getLocWithOffset(3));
1078    StringRef MagicMarkerText;
1079    switch (RC.getKind()) {
1080    case RawComment::RCK_OrdinaryBCPL:
1081      MagicMarkerText = "///<";
1082      break;
1083    case RawComment::RCK_OrdinaryC:
1084      MagicMarkerText = "/**<";
1085      break;
1086    default:
1087      llvm_unreachable("if this is an almost Doxygen comment, "
1088                       "it should be ordinary");
1089    }
1090    Diag(Comment.getBegin(), diag::warn_not_a_doxygen_trailing_member_comment) <<
1091      FixItHint::CreateReplacement(MagicMarkerRange, MagicMarkerText);
1092  }
1093  Context.addComment(RC);
1094}
1095
1096// Pin this vtable to this file.
1097ExternalSemaSource::~ExternalSemaSource() {}
1098
1099void ExternalSemaSource::ReadMethodPool(Selector Sel) { }
1100
1101void ExternalSemaSource::ReadKnownNamespaces(
1102                           SmallVectorImpl<NamespaceDecl *> &Namespaces) {
1103}
1104
1105void ExternalSemaSource::ReadUndefinedButUsed(
1106                       llvm::DenseMap<NamedDecl *, SourceLocation> &Undefined) {
1107}
1108
1109void PrettyDeclStackTraceEntry::print(raw_ostream &OS) const {
1110  SourceLocation Loc = this->Loc;
1111  if (!Loc.isValid() && TheDecl) Loc = TheDecl->getLocation();
1112  if (Loc.isValid()) {
1113    Loc.print(OS, S.getSourceManager());
1114    OS << ": ";
1115  }
1116  OS << Message;
1117
1118  if (TheDecl && isa<NamedDecl>(TheDecl)) {
1119    std::string Name = cast<NamedDecl>(TheDecl)->getNameAsString();
1120    if (!Name.empty())
1121      OS << " '" << Name << '\'';
1122  }
1123
1124  OS << '\n';
1125}
1126
1127/// \brief Figure out if an expression could be turned into a call.
1128///
1129/// Use this when trying to recover from an error where the programmer may have
1130/// written just the name of a function instead of actually calling it.
1131///
1132/// \param E - The expression to examine.
1133/// \param ZeroArgCallReturnTy - If the expression can be turned into a call
1134///  with no arguments, this parameter is set to the type returned by such a
1135///  call; otherwise, it is set to an empty QualType.
1136/// \param OverloadSet - If the expression is an overloaded function
1137///  name, this parameter is populated with the decls of the various overloads.
1138bool Sema::tryExprAsCall(Expr &E, QualType &ZeroArgCallReturnTy,
1139                         UnresolvedSetImpl &OverloadSet) {
1140  ZeroArgCallReturnTy = QualType();
1141  OverloadSet.clear();
1142
1143  const OverloadExpr *Overloads = NULL;
1144  bool IsMemExpr = false;
1145  if (E.getType() == Context.OverloadTy) {
1146    OverloadExpr::FindResult FR = OverloadExpr::find(const_cast<Expr*>(&E));
1147
1148    // Ignore overloads that are pointer-to-member constants.
1149    if (FR.HasFormOfMemberPointer)
1150      return false;
1151
1152    Overloads = FR.Expression;
1153  } else if (E.getType() == Context.BoundMemberTy) {
1154    Overloads = dyn_cast<UnresolvedMemberExpr>(E.IgnoreParens());
1155    IsMemExpr = true;
1156  }
1157
1158  bool Ambiguous = false;
1159
1160  if (Overloads) {
1161    for (OverloadExpr::decls_iterator it = Overloads->decls_begin(),
1162         DeclsEnd = Overloads->decls_end(); it != DeclsEnd; ++it) {
1163      OverloadSet.addDecl(*it);
1164
1165      // Check whether the function is a non-template, non-member which takes no
1166      // arguments.
1167      if (IsMemExpr)
1168        continue;
1169      if (const FunctionDecl *OverloadDecl
1170            = dyn_cast<FunctionDecl>((*it)->getUnderlyingDecl())) {
1171        if (OverloadDecl->getMinRequiredArguments() == 0) {
1172          if (!ZeroArgCallReturnTy.isNull() && !Ambiguous) {
1173            ZeroArgCallReturnTy = QualType();
1174            Ambiguous = true;
1175          } else
1176            ZeroArgCallReturnTy = OverloadDecl->getResultType();
1177        }
1178      }
1179    }
1180
1181    // If it's not a member, use better machinery to try to resolve the call
1182    if (!IsMemExpr)
1183      return !ZeroArgCallReturnTy.isNull();
1184  }
1185
1186  // Attempt to call the member with no arguments - this will correctly handle
1187  // member templates with defaults/deduction of template arguments, overloads
1188  // with default arguments, etc.
1189  if (IsMemExpr && !E.isTypeDependent()) {
1190    bool Suppress = getDiagnostics().getSuppressAllDiagnostics();
1191    getDiagnostics().setSuppressAllDiagnostics(true);
1192    ExprResult R = BuildCallToMemberFunction(NULL, &E, SourceLocation(), None,
1193                                             SourceLocation());
1194    getDiagnostics().setSuppressAllDiagnostics(Suppress);
1195    if (R.isUsable()) {
1196      ZeroArgCallReturnTy = R.get()->getType();
1197      return true;
1198    }
1199    return false;
1200  }
1201
1202  if (const DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(E.IgnoreParens())) {
1203    if (const FunctionDecl *Fun = dyn_cast<FunctionDecl>(DeclRef->getDecl())) {
1204      if (Fun->getMinRequiredArguments() == 0)
1205        ZeroArgCallReturnTy = Fun->getResultType();
1206      return true;
1207    }
1208  }
1209
1210  // We don't have an expression that's convenient to get a FunctionDecl from,
1211  // but we can at least check if the type is "function of 0 arguments".
1212  QualType ExprTy = E.getType();
1213  const FunctionType *FunTy = NULL;
1214  QualType PointeeTy = ExprTy->getPointeeType();
1215  if (!PointeeTy.isNull())
1216    FunTy = PointeeTy->getAs<FunctionType>();
1217  if (!FunTy)
1218    FunTy = ExprTy->getAs<FunctionType>();
1219
1220  if (const FunctionProtoType *FPT =
1221      dyn_cast_or_null<FunctionProtoType>(FunTy)) {
1222    if (FPT->getNumArgs() == 0)
1223      ZeroArgCallReturnTy = FunTy->getResultType();
1224    return true;
1225  }
1226  return false;
1227}
1228
1229/// \brief Give notes for a set of overloads.
1230///
1231/// A companion to tryExprAsCall. In cases when the name that the programmer
1232/// wrote was an overloaded function, we may be able to make some guesses about
1233/// plausible overloads based on their return types; such guesses can be handed
1234/// off to this method to be emitted as notes.
1235///
1236/// \param Overloads - The overloads to note.
1237/// \param FinalNoteLoc - If we've suppressed printing some overloads due to
1238///  -fshow-overloads=best, this is the location to attach to the note about too
1239///  many candidates. Typically this will be the location of the original
1240///  ill-formed expression.
1241static void noteOverloads(Sema &S, const UnresolvedSetImpl &Overloads,
1242                          const SourceLocation FinalNoteLoc) {
1243  int ShownOverloads = 0;
1244  int SuppressedOverloads = 0;
1245  for (UnresolvedSetImpl::iterator It = Overloads.begin(),
1246       DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) {
1247    // FIXME: Magic number for max shown overloads stolen from
1248    // OverloadCandidateSet::NoteCandidates.
1249    if (ShownOverloads >= 4 && S.Diags.getShowOverloads() == Ovl_Best) {
1250      ++SuppressedOverloads;
1251      continue;
1252    }
1253
1254    NamedDecl *Fn = (*It)->getUnderlyingDecl();
1255    S.Diag(Fn->getLocation(), diag::note_possible_target_of_call);
1256    ++ShownOverloads;
1257  }
1258
1259  if (SuppressedOverloads)
1260    S.Diag(FinalNoteLoc, diag::note_ovl_too_many_candidates)
1261      << SuppressedOverloads;
1262}
1263
1264static void notePlausibleOverloads(Sema &S, SourceLocation Loc,
1265                                   const UnresolvedSetImpl &Overloads,
1266                                   bool (*IsPlausibleResult)(QualType)) {
1267  if (!IsPlausibleResult)
1268    return noteOverloads(S, Overloads, Loc);
1269
1270  UnresolvedSet<2> PlausibleOverloads;
1271  for (OverloadExpr::decls_iterator It = Overloads.begin(),
1272         DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) {
1273    const FunctionDecl *OverloadDecl = cast<FunctionDecl>(*It);
1274    QualType OverloadResultTy = OverloadDecl->getResultType();
1275    if (IsPlausibleResult(OverloadResultTy))
1276      PlausibleOverloads.addDecl(It.getDecl());
1277  }
1278  noteOverloads(S, PlausibleOverloads, Loc);
1279}
1280
1281/// Determine whether the given expression can be called by just
1282/// putting parentheses after it.  Notably, expressions with unary
1283/// operators can't be because the unary operator will start parsing
1284/// outside the call.
1285static bool IsCallableWithAppend(Expr *E) {
1286  E = E->IgnoreImplicit();
1287  return (!isa<CStyleCastExpr>(E) &&
1288          !isa<UnaryOperator>(E) &&
1289          !isa<BinaryOperator>(E) &&
1290          !isa<CXXOperatorCallExpr>(E));
1291}
1292
1293bool Sema::tryToRecoverWithCall(ExprResult &E, const PartialDiagnostic &PD,
1294                                bool ForceComplain,
1295                                bool (*IsPlausibleResult)(QualType)) {
1296  SourceLocation Loc = E.get()->getExprLoc();
1297  SourceRange Range = E.get()->getSourceRange();
1298
1299  QualType ZeroArgCallTy;
1300  UnresolvedSet<4> Overloads;
1301  if (tryExprAsCall(*E.get(), ZeroArgCallTy, Overloads) &&
1302      !ZeroArgCallTy.isNull() &&
1303      (!IsPlausibleResult || IsPlausibleResult(ZeroArgCallTy))) {
1304    // At this point, we know E is potentially callable with 0
1305    // arguments and that it returns something of a reasonable type,
1306    // so we can emit a fixit and carry on pretending that E was
1307    // actually a CallExpr.
1308    SourceLocation ParenInsertionLoc = PP.getLocForEndOfToken(Range.getEnd());
1309    Diag(Loc, PD)
1310      << /*zero-arg*/ 1 << Range
1311      << (IsCallableWithAppend(E.get())
1312          ? FixItHint::CreateInsertion(ParenInsertionLoc, "()")
1313          : FixItHint());
1314    notePlausibleOverloads(*this, Loc, Overloads, IsPlausibleResult);
1315
1316    // FIXME: Try this before emitting the fixit, and suppress diagnostics
1317    // while doing so.
1318    E = ActOnCallExpr(0, E.take(), Range.getEnd(), None,
1319                      Range.getEnd().getLocWithOffset(1));
1320    return true;
1321  }
1322
1323  if (!ForceComplain) return false;
1324
1325  Diag(Loc, PD) << /*not zero-arg*/ 0 << Range;
1326  notePlausibleOverloads(*this, Loc, Overloads, IsPlausibleResult);
1327  E = ExprError();
1328  return true;
1329}
1330
1331IdentifierInfo *Sema::getSuperIdentifier() const {
1332  if (!Ident_super)
1333    Ident_super = &Context.Idents.get("super");
1334  return Ident_super;
1335}
1336
1337IdentifierInfo *Sema::getFloat128Identifier() const {
1338  if (!Ident___float128)
1339    Ident___float128 = &Context.Idents.get("__float128");
1340  return Ident___float128;
1341}
1342
1343void Sema::PushCapturedRegionScope(Scope *S, CapturedDecl *CD, RecordDecl *RD,
1344                                   CapturedRegionKind K) {
1345  CapturingScopeInfo *CSI = new CapturedRegionScopeInfo(getDiagnostics(), S, CD, RD,
1346                                                        CD->getContextParam(), K);
1347  CSI->ReturnType = Context.VoidTy;
1348  FunctionScopes.push_back(CSI);
1349}
1350
1351CapturedRegionScopeInfo *Sema::getCurCapturedRegion() {
1352  if (FunctionScopes.empty())
1353    return 0;
1354
1355  return dyn_cast<CapturedRegionScopeInfo>(FunctionScopes.back());
1356}
1357