Sema.cpp revision 8c045ace381972f41d385b0a661ccf172834f459 
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), Ident_super(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  if (PackContext) FreePackedContext();
177  if (VisContext) FreeVisContext();
178  delete TheTargetAttributesSema;
179  MSStructPragmaOn = false;
180  // Kill all the active scopes.
181  for (unsigned I = 1, E = FunctionScopes.size(); I != E; ++I)
182    delete FunctionScopes[I];
183  if (FunctionScopes.size() == 1)
184    delete FunctionScopes[0];
185
186  // Tell the SemaConsumer to forget about us; we're going out of scope.
187  if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
188    SC->ForgetSema();
189
190  // Detach from the external Sema source.
191  if (ExternalSemaSource *ExternalSema
192        = dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
193    ExternalSema->ForgetSema();
194
195  // If Sema's ExternalSource is the multiplexer - we own it.
196  if (isMultiplexExternalSource)
197    delete ExternalSource;
198}
199
200/// makeUnavailableInSystemHeader - There is an error in the current
201/// context.  If we're still in a system header, and we can plausibly
202/// make the relevant declaration unavailable instead of erroring, do
203/// so and return true.
204bool Sema::makeUnavailableInSystemHeader(SourceLocation loc,
205                                         StringRef msg) {
206  // If we're not in a function, it's an error.
207  FunctionDecl *fn = dyn_cast<FunctionDecl>(CurContext);
208  if (!fn) return false;
209
210  // If we're in template instantiation, it's an error.
211  if (!ActiveTemplateInstantiations.empty())
212    return false;
213
214  // If that function's not in a system header, it's an error.
215  if (!Context.getSourceManager().isInSystemHeader(loc))
216    return false;
217
218  // If the function is already unavailable, it's not an error.
219  if (fn->hasAttr<UnavailableAttr>()) return true;
220
221  fn->addAttr(new (Context) UnavailableAttr(loc, Context, msg));
222  return true;
223}
224
225ASTMutationListener *Sema::getASTMutationListener() const {
226  return getASTConsumer().GetASTMutationListener();
227}
228
229///\brief Registers an external source. If an external source already exists,
230/// creates a multiplex external source and appends to it.
231///
232///\param[in] E - A non-null external sema source.
233///
234void Sema::addExternalSource(ExternalSemaSource *E) {
235  assert(E && "Cannot use with NULL ptr");
236
237  if (!ExternalSource) {
238    ExternalSource = E;
239    return;
240  }
241
242  if (isMultiplexExternalSource)
243    static_cast<MultiplexExternalSemaSource*>(ExternalSource)->addSource(*E);
244  else {
245    ExternalSource = new MultiplexExternalSemaSource(*ExternalSource, *E);
246    isMultiplexExternalSource = true;
247  }
248}
249
250/// \brief Print out statistics about the semantic analysis.
251void Sema::PrintStats() const {
252  llvm::errs() << "\n*** Semantic Analysis Stats:\n";
253  llvm::errs() << NumSFINAEErrors << " SFINAE diagnostics trapped.\n";
254
255  BumpAlloc.PrintStats();
256  AnalysisWarnings.PrintStats();
257}
258
259/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast.
260/// If there is already an implicit cast, merge into the existing one.
261/// The result is of the given category.
262ExprResult Sema::ImpCastExprToType(Expr *E, QualType Ty,
263                                   CastKind Kind, ExprValueKind VK,
264                                   const CXXCastPath *BasePath,
265                                   CheckedConversionKind CCK) {
266#ifndef NDEBUG
267  if (VK == VK_RValue && !E->isRValue()) {
268    switch (Kind) {
269    default:
270      assert(0 && "can't implicitly cast lvalue to rvalue with this cast kind");
271    case CK_LValueToRValue:
272    case CK_ArrayToPointerDecay:
273    case CK_FunctionToPointerDecay:
274    case CK_ToVoid:
275      break;
276    }
277  }
278  assert((VK == VK_RValue || !E->isRValue()) && "can't cast rvalue to lvalue");
279#endif
280
281  QualType ExprTy = Context.getCanonicalType(E->getType());
282  QualType TypeTy = Context.getCanonicalType(Ty);
283
284  if (ExprTy == TypeTy)
285    return Owned(E);
286
287  if (getLangOpts().ObjCAutoRefCount)
288    CheckObjCARCConversion(SourceRange(), Ty, E, CCK);
289
290  // If this is a derived-to-base cast to a through a virtual base, we
291  // need a vtable.
292  if (Kind == CK_DerivedToBase &&
293      BasePathInvolvesVirtualBase(*BasePath)) {
294    QualType T = E->getType();
295    if (const PointerType *Pointer = T->getAs<PointerType>())
296      T = Pointer->getPointeeType();
297    if (const RecordType *RecordTy = T->getAs<RecordType>())
298      MarkVTableUsed(E->getLocStart(),
299                     cast<CXXRecordDecl>(RecordTy->getDecl()));
300  }
301
302  if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(E)) {
303    if (ImpCast->getCastKind() == Kind && (!BasePath || BasePath->empty())) {
304      ImpCast->setType(Ty);
305      ImpCast->setValueKind(VK);
306      return Owned(E);
307    }
308  }
309
310  return Owned(ImplicitCastExpr::Create(Context, Ty, Kind, E, BasePath, VK));
311}
312
313/// ScalarTypeToBooleanCastKind - Returns the cast kind corresponding
314/// to the conversion from scalar type ScalarTy to the Boolean type.
315CastKind Sema::ScalarTypeToBooleanCastKind(QualType ScalarTy) {
316  switch (ScalarTy->getScalarTypeKind()) {
317  case Type::STK_Bool: return CK_NoOp;
318  case Type::STK_CPointer: return CK_PointerToBoolean;
319  case Type::STK_BlockPointer: return CK_PointerToBoolean;
320  case Type::STK_ObjCObjectPointer: return CK_PointerToBoolean;
321  case Type::STK_MemberPointer: return CK_MemberPointerToBoolean;
322  case Type::STK_Integral: return CK_IntegralToBoolean;
323  case Type::STK_Floating: return CK_FloatingToBoolean;
324  case Type::STK_IntegralComplex: return CK_IntegralComplexToBoolean;
325  case Type::STK_FloatingComplex: return CK_FloatingComplexToBoolean;
326  }
327  return CK_Invalid;
328}
329
330/// \brief Used to prune the decls of Sema's UnusedFileScopedDecls vector.
331static bool ShouldRemoveFromUnused(Sema *SemaRef, const DeclaratorDecl *D) {
332  if (D->getMostRecentDecl()->isUsed())
333    return true;
334
335  if (D->hasExternalLinkage())
336    return true;
337
338  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
339    // UnusedFileScopedDecls stores the first declaration.
340    // The declaration may have become definition so check again.
341    const FunctionDecl *DeclToCheck;
342    if (FD->hasBody(DeclToCheck))
343      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
344
345    // Later redecls may add new information resulting in not having to warn,
346    // so check again.
347    DeclToCheck = FD->getMostRecentDecl();
348    if (DeclToCheck != FD)
349      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
350  }
351
352  if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
353    // UnusedFileScopedDecls stores the first declaration.
354    // The declaration may have become definition so check again.
355    const VarDecl *DeclToCheck = VD->getDefinition();
356    if (DeclToCheck)
357      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
358
359    // Later redecls may add new information resulting in not having to warn,
360    // so check again.
361    DeclToCheck = VD->getMostRecentDecl();
362    if (DeclToCheck != VD)
363      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
364  }
365
366  return false;
367}
368
369namespace {
370  struct SortUndefinedButUsed {
371    const SourceManager &SM;
372    explicit SortUndefinedButUsed(SourceManager &SM) : SM(SM) {}
373
374    bool operator()(const std::pair<NamedDecl *, SourceLocation> &l,
375                    const std::pair<NamedDecl *, SourceLocation> &r) const {
376      if (l.second.isValid() && !r.second.isValid())
377        return true;
378      if (!l.second.isValid() && r.second.isValid())
379        return false;
380      if (l.second != r.second)
381        return SM.isBeforeInTranslationUnit(l.second, r.second);
382      return SM.isBeforeInTranslationUnit(l.first->getLocation(),
383                                          r.first->getLocation());
384    }
385  };
386}
387
388/// Obtains a sorted list of functions that are undefined but ODR-used.
389void Sema::getUndefinedButUsed(
390    SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> > &Undefined) {
391  for (llvm::DenseMap<NamedDecl *, SourceLocation>::iterator
392         I = UndefinedButUsed.begin(), E = UndefinedButUsed.end();
393       I != E; ++I) {
394    NamedDecl *ND = I->first;
395
396    // Ignore attributes that have become invalid.
397    if (ND->isInvalidDecl()) continue;
398
399    // __attribute__((weakref)) is basically a definition.
400    if (ND->hasAttr<WeakRefAttr>()) continue;
401
402    if (FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
403      if (FD->isDefined())
404        continue;
405      if (FD->hasExternalLinkage() &&
406          !FD->getMostRecentDecl()->isInlined())
407        continue;
408    } else {
409      if (cast<VarDecl>(ND)->hasDefinition() != VarDecl::DeclarationOnly)
410        continue;
411      if (ND->hasExternalLinkage())
412        continue;
413    }
414
415    Undefined.push_back(std::make_pair(ND, I->second));
416  }
417
418  // Sort (in order of use site) so that we're not dependent on the iteration
419  // order through an llvm::DenseMap.
420  std::sort(Undefined.begin(), Undefined.end(),
421            SortUndefinedButUsed(Context.getSourceManager()));
422}
423
424/// checkUndefinedButUsed - Check for undefined objects with internal linkage
425/// or that are inline.
426static void checkUndefinedButUsed(Sema &S) {
427  if (S.UndefinedButUsed.empty()) return;
428
429  // Collect all the still-undefined entities with internal linkage.
430  SmallVector<std::pair<NamedDecl *, SourceLocation>, 16> Undefined;
431  S.getUndefinedButUsed(Undefined);
432  if (Undefined.empty()) return;
433
434  for (SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> >::iterator
435         I = Undefined.begin(), E = Undefined.end(); I != E; ++I) {
436    NamedDecl *ND = I->first;
437
438    if (ND->getLinkage() != ExternalLinkage) {
439      S.Diag(ND->getLocation(), diag::warn_undefined_internal)
440        << isa<VarDecl>(ND) << ND;
441    } else {
442      assert(cast<FunctionDecl>(ND)->getMostRecentDecl()->isInlined() &&
443             "used object requires definition but isn't inline or internal?");
444      S.Diag(ND->getLocation(), diag::warn_undefined_inline) << ND;
445    }
446    if (I->second.isValid())
447      S.Diag(I->second, diag::note_used_here);
448  }
449}
450
451void Sema::LoadExternalWeakUndeclaredIdentifiers() {
452  if (!ExternalSource)
453    return;
454
455  SmallVector<std::pair<IdentifierInfo *, WeakInfo>, 4> WeakIDs;
456  ExternalSource->ReadWeakUndeclaredIdentifiers(WeakIDs);
457  for (unsigned I = 0, N = WeakIDs.size(); I != N; ++I) {
458    llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator Pos
459      = WeakUndeclaredIdentifiers.find(WeakIDs[I].first);
460    if (Pos != WeakUndeclaredIdentifiers.end())
461      continue;
462
463    WeakUndeclaredIdentifiers.insert(WeakIDs[I]);
464  }
465}
466
467
468typedef llvm::DenseMap<const CXXRecordDecl*, bool> RecordCompleteMap;
469
470/// \brief Returns true, if all methods and nested classes of the given
471/// CXXRecordDecl are defined in this translation unit.
472///
473/// Should only be called from ActOnEndOfTranslationUnit so that all
474/// definitions are actually read.
475static bool MethodsAndNestedClassesComplete(const CXXRecordDecl *RD,
476                                            RecordCompleteMap &MNCComplete) {
477  RecordCompleteMap::iterator Cache = MNCComplete.find(RD);
478  if (Cache != MNCComplete.end())
479    return Cache->second;
480  if (!RD->isCompleteDefinition())
481    return false;
482  bool Complete = true;
483  for (DeclContext::decl_iterator I = RD->decls_begin(),
484                                  E = RD->decls_end();
485       I != E && Complete; ++I) {
486    if (const CXXMethodDecl *M = dyn_cast<CXXMethodDecl>(*I))
487      Complete = M->isDefined() || (M->isPure() && !isa<CXXDestructorDecl>(M));
488    else if (const FunctionTemplateDecl *F = dyn_cast<FunctionTemplateDecl>(*I))
489      Complete = F->getTemplatedDecl()->isDefined();
490    else if (const CXXRecordDecl *R = dyn_cast<CXXRecordDecl>(*I)) {
491      if (R->isInjectedClassName())
492        continue;
493      if (R->hasDefinition())
494        Complete = MethodsAndNestedClassesComplete(R->getDefinition(),
495                                                   MNCComplete);
496      else
497        Complete = false;
498    }
499  }
500  MNCComplete[RD] = Complete;
501  return Complete;
502}
503
504/// \brief Returns true, if the given CXXRecordDecl is fully defined in this
505/// translation unit, i.e. all methods are defined or pure virtual and all
506/// friends, friend functions and nested classes are fully defined in this
507/// translation unit.
508///
509/// Should only be called from ActOnEndOfTranslationUnit so that all
510/// definitions are actually read.
511static bool IsRecordFullyDefined(const CXXRecordDecl *RD,
512                                 RecordCompleteMap &RecordsComplete,
513                                 RecordCompleteMap &MNCComplete) {
514  RecordCompleteMap::iterator Cache = RecordsComplete.find(RD);
515  if (Cache != RecordsComplete.end())
516    return Cache->second;
517  bool Complete = MethodsAndNestedClassesComplete(RD, MNCComplete);
518  for (CXXRecordDecl::friend_iterator I = RD->friend_begin(),
519                                      E = RD->friend_end();
520       I != E && Complete; ++I) {
521    // Check if friend classes and methods are complete.
522    if (TypeSourceInfo *TSI = (*I)->getFriendType()) {
523      // Friend classes are available as the TypeSourceInfo of the FriendDecl.
524      if (CXXRecordDecl *FriendD = TSI->getType()->getAsCXXRecordDecl())
525        Complete = MethodsAndNestedClassesComplete(FriendD, MNCComplete);
526      else
527        Complete = false;
528    } else {
529      // Friend functions are available through the NamedDecl of FriendDecl.
530      if (const FunctionDecl *FD =
531          dyn_cast<FunctionDecl>((*I)->getFriendDecl()))
532        Complete = FD->isDefined();
533      else
534        // This is a template friend, give up.
535        Complete = false;
536    }
537  }
538  RecordsComplete[RD] = Complete;
539  return Complete;
540}
541
542/// ActOnEndOfTranslationUnit - This is called at the very end of the
543/// translation unit when EOF is reached and all but the top-level scope is
544/// popped.
545void Sema::ActOnEndOfTranslationUnit() {
546  assert(DelayedDiagnostics.getCurrentPool() == NULL
547         && "reached end of translation unit with a pool attached?");
548
549  // If code completion is enabled, don't perform any end-of-translation-unit
550  // work.
551  if (PP.isCodeCompletionEnabled())
552    return;
553
554  // Only complete translation units define vtables and perform implicit
555  // instantiations.
556  if (TUKind == TU_Complete) {
557    DiagnoseUseOfUnimplementedSelectors();
558
559    // If any dynamic classes have their key function defined within
560    // this translation unit, then those vtables are considered "used" and must
561    // be emitted.
562    for (DynamicClassesType::iterator I = DynamicClasses.begin(ExternalSource),
563                                      E = DynamicClasses.end();
564         I != E; ++I) {
565      assert(!(*I)->isDependentType() &&
566             "Should not see dependent types here!");
567      if (const CXXMethodDecl *KeyFunction = Context.getCurrentKeyFunction(*I)) {
568        const FunctionDecl *Definition = 0;
569        if (KeyFunction->hasBody(Definition))
570          MarkVTableUsed(Definition->getLocation(), *I, true);
571      }
572    }
573
574    // If DefinedUsedVTables ends up marking any virtual member functions it
575    // might lead to more pending template instantiations, which we then need
576    // to instantiate.
577    DefineUsedVTables();
578
579    // C++: Perform implicit template instantiations.
580    //
581    // FIXME: When we perform these implicit instantiations, we do not
582    // carefully keep track of the point of instantiation (C++ [temp.point]).
583    // This means that name lookup that occurs within the template
584    // instantiation will always happen at the end of the translation unit,
585    // so it will find some names that should not be found. Although this is
586    // common behavior for C++ compilers, it is technically wrong. In the
587    // future, we either need to be able to filter the results of name lookup
588    // or we need to perform template instantiations earlier.
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.back();
634        Stack.pop_back();
635
636        // Resolve the exported declarations and conflicts.
637        // FIXME: Actually complain, once we figure out how to teach the
638        // diagnostic client to deal with complaints in the module map at this
639        // point.
640        ModMap.resolveExports(Mod, /*Complain=*/false);
641        ModMap.resolveConflicts(Mod, /*Complain=*/false);
642
643        // Queue the submodules, so their exports will also be resolved.
644        for (Module::submodule_iterator Sub = Mod->submodule_begin(),
645                                     SubEnd = Mod->submodule_end();
646             Sub != SubEnd; ++Sub) {
647          Stack.push_back(*Sub);
648        }
649      }
650    }
651
652    // Modules don't need any of the checking below.
653    TUScope = 0;
654    return;
655  }
656
657  // C99 6.9.2p2:
658  //   A declaration of an identifier for an object that has file
659  //   scope without an initializer, and without a storage-class
660  //   specifier or with the storage-class specifier static,
661  //   constitutes a tentative definition. If a translation unit
662  //   contains one or more tentative definitions for an identifier,
663  //   and the translation unit contains no external definition for
664  //   that identifier, then the behavior is exactly as if the
665  //   translation unit contains a file scope declaration of that
666  //   identifier, with the composite type as of the end of the
667  //   translation unit, with an initializer equal to 0.
668  llvm::SmallSet<VarDecl *, 32> Seen;
669  for (TentativeDefinitionsType::iterator
670            T = TentativeDefinitions.begin(ExternalSource),
671         TEnd = TentativeDefinitions.end();
672       T != TEnd; ++T)
673  {
674    VarDecl *VD = (*T)->getActingDefinition();
675
676    // If the tentative definition was completed, getActingDefinition() returns
677    // null. If we've already seen this variable before, insert()'s second
678    // return value is false.
679    if (VD == 0 || VD->isInvalidDecl() || !Seen.insert(VD))
680      continue;
681
682    if (const IncompleteArrayType *ArrayT
683        = Context.getAsIncompleteArrayType(VD->getType())) {
684      if (RequireCompleteType(VD->getLocation(),
685                              ArrayT->getElementType(),
686                              diag::err_tentative_def_incomplete_type_arr)) {
687        VD->setInvalidDecl();
688        continue;
689      }
690
691      // Set the length of the array to 1 (C99 6.9.2p5).
692      Diag(VD->getLocation(), diag::warn_tentative_incomplete_array);
693      llvm::APInt One(Context.getTypeSize(Context.getSizeType()), true);
694      QualType T = Context.getConstantArrayType(ArrayT->getElementType(),
695                                                One, ArrayType::Normal, 0);
696      VD->setType(T);
697    } else if (RequireCompleteType(VD->getLocation(), VD->getType(),
698                                   diag::err_tentative_def_incomplete_type))
699      VD->setInvalidDecl();
700
701    CheckCompleteVariableDeclaration(VD);
702
703    // Notify the consumer that we've completed a tentative definition.
704    if (!VD->isInvalidDecl())
705      Consumer.CompleteTentativeDefinition(VD);
706
707  }
708
709  // If there were errors, disable 'unused' warnings since they will mostly be
710  // noise.
711  if (!Diags.hasErrorOccurred()) {
712    // Output warning for unused file scoped decls.
713    for (UnusedFileScopedDeclsType::iterator
714           I = UnusedFileScopedDecls.begin(ExternalSource),
715           E = UnusedFileScopedDecls.end(); I != E; ++I) {
716      if (ShouldRemoveFromUnused(this, *I))
717        continue;
718
719      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) {
720        const FunctionDecl *DiagD;
721        if (!FD->hasBody(DiagD))
722          DiagD = FD;
723        if (DiagD->isDeleted())
724          continue; // Deleted functions are supposed to be unused.
725        if (DiagD->isReferenced()) {
726          if (isa<CXXMethodDecl>(DiagD))
727            Diag(DiagD->getLocation(), diag::warn_unneeded_member_function)
728                  << DiagD->getDeclName();
729          else {
730            if (FD->getStorageClass() == SC_Static &&
731                !FD->isInlineSpecified() &&
732                !SourceMgr.isFromMainFile(
733                   SourceMgr.getExpansionLoc(FD->getLocation())))
734              Diag(DiagD->getLocation(), diag::warn_unneeded_static_internal_decl)
735                << DiagD->getDeclName();
736            else
737              Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
738                   << /*function*/0 << DiagD->getDeclName();
739          }
740        } else {
741          Diag(DiagD->getLocation(),
742               isa<CXXMethodDecl>(DiagD) ? diag::warn_unused_member_function
743                                         : diag::warn_unused_function)
744                << DiagD->getDeclName();
745        }
746      } else {
747        const VarDecl *DiagD = cast<VarDecl>(*I)->getDefinition();
748        if (!DiagD)
749          DiagD = cast<VarDecl>(*I);
750        if (DiagD->isReferenced()) {
751          Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
752                << /*variable*/1 << DiagD->getDeclName();
753        } else if (getSourceManager().isFromMainFile(DiagD->getLocation())) {
754          // If the declaration is in a header which is included into multiple
755          // TUs, it will declare one variable per TU, and one of the other
756          // variables may be used. So, only warn if the declaration is in the
757          // main file.
758          Diag(DiagD->getLocation(), diag::warn_unused_variable)
759              << DiagD->getDeclName();
760        }
761      }
762    }
763
764    if (ExternalSource)
765      ExternalSource->ReadUndefinedButUsed(UndefinedButUsed);
766    checkUndefinedButUsed(*this);
767  }
768
769  if (Diags.getDiagnosticLevel(diag::warn_unused_private_field,
770                               SourceLocation())
771        != DiagnosticsEngine::Ignored) {
772    RecordCompleteMap RecordsComplete;
773    RecordCompleteMap MNCComplete;
774    for (NamedDeclSetType::iterator I = UnusedPrivateFields.begin(),
775         E = UnusedPrivateFields.end(); I != E; ++I) {
776      const NamedDecl *D = *I;
777      const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D->getDeclContext());
778      if (RD && !RD->isUnion() &&
779          IsRecordFullyDefined(RD, RecordsComplete, MNCComplete)) {
780        Diag(D->getLocation(), diag::warn_unused_private_field)
781              << D->getDeclName();
782      }
783    }
784  }
785
786  // Check we've noticed that we're no longer parsing the initializer for every
787  // variable. If we miss cases, then at best we have a performance issue and
788  // at worst a rejects-valid bug.
789  assert(ParsingInitForAutoVars.empty() &&
790         "Didn't unmark var as having its initializer parsed");
791
792  TUScope = 0;
793}
794
795
796//===----------------------------------------------------------------------===//
797// Helper functions.
798//===----------------------------------------------------------------------===//
799
800DeclContext *Sema::getFunctionLevelDeclContext() {
801  DeclContext *DC = CurContext;
802
803  while (true) {
804    if (isa<BlockDecl>(DC) || isa<EnumDecl>(DC) || isa<CapturedDecl>(DC)) {
805      DC = DC->getParent();
806    } else if (isa<CXXMethodDecl>(DC) &&
807               cast<CXXMethodDecl>(DC)->getOverloadedOperator() == OO_Call &&
808               cast<CXXRecordDecl>(DC->getParent())->isLambda()) {
809      DC = DC->getParent()->getParent();
810    }
811    else break;
812  }
813
814  return DC;
815}
816
817/// getCurFunctionDecl - If inside of a function body, this returns a pointer
818/// to the function decl for the function being parsed.  If we're currently
819/// in a 'block', this returns the containing context.
820FunctionDecl *Sema::getCurFunctionDecl() {
821  DeclContext *DC = getFunctionLevelDeclContext();
822  return dyn_cast<FunctionDecl>(DC);
823}
824
825ObjCMethodDecl *Sema::getCurMethodDecl() {
826  DeclContext *DC = getFunctionLevelDeclContext();
827  return dyn_cast<ObjCMethodDecl>(DC);
828}
829
830NamedDecl *Sema::getCurFunctionOrMethodDecl() {
831  DeclContext *DC = getFunctionLevelDeclContext();
832  if (isa<ObjCMethodDecl>(DC) || isa<FunctionDecl>(DC))
833    return cast<NamedDecl>(DC);
834  return 0;
835}
836
837void Sema::EmitCurrentDiagnostic(unsigned DiagID) {
838  // FIXME: It doesn't make sense to me that DiagID is an incoming argument here
839  // and yet we also use the current diag ID on the DiagnosticsEngine. This has
840  // been made more painfully obvious by the refactor that introduced this
841  // function, but it is possible that the incoming argument can be
842  // eliminnated. If it truly cannot be (for example, there is some reentrancy
843  // issue I am not seeing yet), then there should at least be a clarifying
844  // comment somewhere.
845  if (Optional<TemplateDeductionInfo*> Info = isSFINAEContext()) {
846    switch (DiagnosticIDs::getDiagnosticSFINAEResponse(
847              Diags.getCurrentDiagID())) {
848    case DiagnosticIDs::SFINAE_Report:
849      // We'll report the diagnostic below.
850      break;
851
852    case DiagnosticIDs::SFINAE_SubstitutionFailure:
853      // Count this failure so that we know that template argument deduction
854      // has failed.
855      ++NumSFINAEErrors;
856
857      // Make a copy of this suppressed diagnostic and store it with the
858      // template-deduction information.
859      if (*Info && !(*Info)->hasSFINAEDiagnostic()) {
860        Diagnostic DiagInfo(&Diags);
861        (*Info)->addSFINAEDiagnostic(DiagInfo.getLocation(),
862                       PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
863      }
864
865      Diags.setLastDiagnosticIgnored();
866      Diags.Clear();
867      return;
868
869    case DiagnosticIDs::SFINAE_AccessControl: {
870      // Per C++ Core Issue 1170, access control is part of SFINAE.
871      // Additionally, the AccessCheckingSFINAE flag can be used to temporarily
872      // make access control a part of SFINAE for the purposes of checking
873      // type traits.
874      if (!AccessCheckingSFINAE && !getLangOpts().CPlusPlus11)
875        break;
876
877      SourceLocation Loc = Diags.getCurrentDiagLoc();
878
879      // Suppress this diagnostic.
880      ++NumSFINAEErrors;
881
882      // Make a copy of this suppressed diagnostic and store it with the
883      // template-deduction information.
884      if (*Info && !(*Info)->hasSFINAEDiagnostic()) {
885        Diagnostic DiagInfo(&Diags);
886        (*Info)->addSFINAEDiagnostic(DiagInfo.getLocation(),
887                       PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
888      }
889
890      Diags.setLastDiagnosticIgnored();
891      Diags.Clear();
892
893      // Now the diagnostic state is clear, produce a C++98 compatibility
894      // warning.
895      Diag(Loc, diag::warn_cxx98_compat_sfinae_access_control);
896
897      // The last diagnostic which Sema produced was ignored. Suppress any
898      // notes attached to it.
899      Diags.setLastDiagnosticIgnored();
900      return;
901    }
902
903    case DiagnosticIDs::SFINAE_Suppress:
904      // Make a copy of this suppressed diagnostic and store it with the
905      // template-deduction information;
906      if (*Info) {
907        Diagnostic DiagInfo(&Diags);
908        (*Info)->addSuppressedDiagnostic(DiagInfo.getLocation(),
909                       PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
910      }
911
912      // Suppress this diagnostic.
913      Diags.setLastDiagnosticIgnored();
914      Diags.Clear();
915      return;
916    }
917  }
918
919  // Set up the context's printing policy based on our current state.
920  Context.setPrintingPolicy(getPrintingPolicy());
921
922  // Emit the diagnostic.
923  if (!Diags.EmitCurrentDiagnostic())
924    return;
925
926  // If this is not a note, and we're in a template instantiation
927  // that is different from the last template instantiation where
928  // we emitted an error, print a template instantiation
929  // backtrace.
930  if (!DiagnosticIDs::isBuiltinNote(DiagID) &&
931      !ActiveTemplateInstantiations.empty() &&
932      ActiveTemplateInstantiations.back()
933        != LastTemplateInstantiationErrorContext) {
934    PrintInstantiationStack();
935    LastTemplateInstantiationErrorContext = ActiveTemplateInstantiations.back();
936  }
937}
938
939Sema::SemaDiagnosticBuilder
940Sema::Diag(SourceLocation Loc, const PartialDiagnostic& PD) {
941  SemaDiagnosticBuilder Builder(Diag(Loc, PD.getDiagID()));
942  PD.Emit(Builder);
943
944  return Builder;
945}
946
947/// \brief Looks through the macro-expansion chain for the given
948/// location, looking for a macro expansion with the given name.
949/// If one is found, returns true and sets the location to that
950/// expansion loc.
951bool Sema::findMacroSpelling(SourceLocation &locref, StringRef name) {
952  SourceLocation loc = locref;
953  if (!loc.isMacroID()) return false;
954
955  // There's no good way right now to look at the intermediate
956  // expansions, so just jump to the expansion location.
957  loc = getSourceManager().getExpansionLoc(loc);
958
959  // If that's written with the name, stop here.
960  SmallVector<char, 16> buffer;
961  if (getPreprocessor().getSpelling(loc, buffer) == name) {
962    locref = loc;
963    return true;
964  }
965  return false;
966}
967
968/// \brief Determines the active Scope associated with the given declaration
969/// context.
970///
971/// This routine maps a declaration context to the active Scope object that
972/// represents that declaration context in the parser. It is typically used
973/// from "scope-less" code (e.g., template instantiation, lazy creation of
974/// declarations) that injects a name for name-lookup purposes and, therefore,
975/// must update the Scope.
976///
977/// \returns The scope corresponding to the given declaraion context, or NULL
978/// if no such scope is open.
979Scope *Sema::getScopeForContext(DeclContext *Ctx) {
980
981  if (!Ctx)
982    return 0;
983
984  Ctx = Ctx->getPrimaryContext();
985  for (Scope *S = getCurScope(); S; S = S->getParent()) {
986    // Ignore scopes that cannot have declarations. This is important for
987    // out-of-line definitions of static class members.
988    if (S->getFlags() & (Scope::DeclScope | Scope::TemplateParamScope))
989      if (DeclContext *Entity = static_cast<DeclContext *> (S->getEntity()))
990        if (Ctx == Entity->getPrimaryContext())
991          return S;
992  }
993
994  return 0;
995}
996
997/// \brief Enter a new function scope
998void Sema::PushFunctionScope() {
999  if (FunctionScopes.size() == 1) {
1000    // Use the "top" function scope rather than having to allocate
1001    // memory for a new scope.
1002    FunctionScopes.back()->Clear();
1003    FunctionScopes.push_back(FunctionScopes.back());
1004    return;
1005  }
1006
1007  FunctionScopes.push_back(new FunctionScopeInfo(getDiagnostics()));
1008}
1009
1010void Sema::PushBlockScope(Scope *BlockScope, BlockDecl *Block) {
1011  FunctionScopes.push_back(new BlockScopeInfo(getDiagnostics(),
1012                                              BlockScope, Block));
1013}
1014
1015void Sema::PushLambdaScope(CXXRecordDecl *Lambda,
1016                           CXXMethodDecl *CallOperator) {
1017  FunctionScopes.push_back(new LambdaScopeInfo(getDiagnostics(), Lambda,
1018                                               CallOperator));
1019}
1020
1021void Sema::PopFunctionScopeInfo(const AnalysisBasedWarnings::Policy *WP,
1022                                const Decl *D, const BlockExpr *blkExpr) {
1023  FunctionScopeInfo *Scope = FunctionScopes.pop_back_val();
1024  assert(!FunctionScopes.empty() && "mismatched push/pop!");
1025
1026  // Issue any analysis-based warnings.
1027  if (WP && D)
1028    AnalysisWarnings.IssueWarnings(*WP, Scope, D, blkExpr);
1029  else {
1030    for (SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator
1031         i = Scope->PossiblyUnreachableDiags.begin(),
1032         e = Scope->PossiblyUnreachableDiags.end();
1033         i != e; ++i) {
1034      const sema::PossiblyUnreachableDiag &D = *i;
1035      Diag(D.Loc, D.PD);
1036    }
1037  }
1038
1039  if (FunctionScopes.back() != Scope) {
1040    delete Scope;
1041  }
1042}
1043
1044void Sema::PushCompoundScope() {
1045  getCurFunction()->CompoundScopes.push_back(CompoundScopeInfo());
1046}
1047
1048void Sema::PopCompoundScope() {
1049  FunctionScopeInfo *CurFunction = getCurFunction();
1050  assert(!CurFunction->CompoundScopes.empty() && "mismatched push/pop");
1051
1052  CurFunction->CompoundScopes.pop_back();
1053}
1054
1055/// \brief Determine whether any errors occurred within this function/method/
1056/// block.
1057bool Sema::hasAnyUnrecoverableErrorsInThisFunction() const {
1058  return getCurFunction()->ErrorTrap.hasUnrecoverableErrorOccurred();
1059}
1060
1061BlockScopeInfo *Sema::getCurBlock() {
1062  if (FunctionScopes.empty())
1063    return 0;
1064
1065  return dyn_cast<BlockScopeInfo>(FunctionScopes.back());
1066}
1067
1068LambdaScopeInfo *Sema::getCurLambda() {
1069  if (FunctionScopes.empty())
1070    return 0;
1071
1072  return dyn_cast<LambdaScopeInfo>(FunctionScopes.back());
1073}
1074
1075void Sema::ActOnComment(SourceRange Comment) {
1076  if (!LangOpts.RetainCommentsFromSystemHeaders &&
1077      SourceMgr.isInSystemHeader(Comment.getBegin()))
1078    return;
1079  RawComment RC(SourceMgr, Comment, false,
1080                LangOpts.CommentOpts.ParseAllComments);
1081  if (RC.isAlmostTrailingComment()) {
1082    SourceRange MagicMarkerRange(Comment.getBegin(),
1083                                 Comment.getBegin().getLocWithOffset(3));
1084    StringRef MagicMarkerText;
1085    switch (RC.getKind()) {
1086    case RawComment::RCK_OrdinaryBCPL:
1087      MagicMarkerText = "///<";
1088      break;
1089    case RawComment::RCK_OrdinaryC:
1090      MagicMarkerText = "/**<";
1091      break;
1092    default:
1093      llvm_unreachable("if this is an almost Doxygen comment, "
1094                       "it should be ordinary");
1095    }
1096    Diag(Comment.getBegin(), diag::warn_not_a_doxygen_trailing_member_comment) <<
1097      FixItHint::CreateReplacement(MagicMarkerRange, MagicMarkerText);
1098  }
1099  Context.addComment(RC);
1100}
1101
1102// Pin this vtable to this file.
1103ExternalSemaSource::~ExternalSemaSource() {}
1104
1105void ExternalSemaSource::ReadMethodPool(Selector Sel) { }
1106
1107void ExternalSemaSource::ReadKnownNamespaces(
1108                           SmallVectorImpl<NamespaceDecl *> &Namespaces) {
1109}
1110
1111void ExternalSemaSource::ReadUndefinedButUsed(
1112                       llvm::DenseMap<NamedDecl *, SourceLocation> &Undefined) {
1113}
1114
1115void PrettyDeclStackTraceEntry::print(raw_ostream &OS) const {
1116  SourceLocation Loc = this->Loc;
1117  if (!Loc.isValid() && TheDecl) Loc = TheDecl->getLocation();
1118  if (Loc.isValid()) {
1119    Loc.print(OS, S.getSourceManager());
1120    OS << ": ";
1121  }
1122  OS << Message;
1123
1124  if (TheDecl && isa<NamedDecl>(TheDecl)) {
1125    std::string Name = cast<NamedDecl>(TheDecl)->getNameAsString();
1126    if (!Name.empty())
1127      OS << " '" << Name << '\'';
1128  }
1129
1130  OS << '\n';
1131}
1132
1133/// \brief Figure out if an expression could be turned into a call.
1134///
1135/// Use this when trying to recover from an error where the programmer may have
1136/// written just the name of a function instead of actually calling it.
1137///
1138/// \param E - The expression to examine.
1139/// \param ZeroArgCallReturnTy - If the expression can be turned into a call
1140///  with no arguments, this parameter is set to the type returned by such a
1141///  call; otherwise, it is set to an empty QualType.
1142/// \param OverloadSet - If the expression is an overloaded function
1143///  name, this parameter is populated with the decls of the various overloads.
1144bool Sema::isExprCallable(const Expr &E, QualType &ZeroArgCallReturnTy,
1145                          UnresolvedSetImpl &OverloadSet) {
1146  ZeroArgCallReturnTy = QualType();
1147  OverloadSet.clear();
1148
1149  if (E.getType() == Context.OverloadTy) {
1150    OverloadExpr::FindResult FR = OverloadExpr::find(const_cast<Expr*>(&E));
1151    const OverloadExpr *Overloads = FR.Expression;
1152
1153    for (OverloadExpr::decls_iterator it = Overloads->decls_begin(),
1154         DeclsEnd = Overloads->decls_end(); it != DeclsEnd; ++it) {
1155      OverloadSet.addDecl(*it);
1156
1157      // Check whether the function is a non-template which takes no
1158      // arguments.
1159      if (const FunctionDecl *OverloadDecl
1160            = dyn_cast<FunctionDecl>((*it)->getUnderlyingDecl())) {
1161        if (OverloadDecl->getMinRequiredArguments() == 0)
1162          ZeroArgCallReturnTy = OverloadDecl->getResultType();
1163      }
1164    }
1165
1166    // Ignore overloads that are pointer-to-member constants.
1167    if (FR.HasFormOfMemberPointer)
1168      return false;
1169
1170    return true;
1171  }
1172
1173  if (const DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(E.IgnoreParens())) {
1174    if (const FunctionDecl *Fun = dyn_cast<FunctionDecl>(DeclRef->getDecl())) {
1175      if (Fun->getMinRequiredArguments() == 0)
1176        ZeroArgCallReturnTy = Fun->getResultType();
1177      return true;
1178    }
1179  }
1180
1181  // We don't have an expression that's convenient to get a FunctionDecl from,
1182  // but we can at least check if the type is "function of 0 arguments".
1183  QualType ExprTy = E.getType();
1184  const FunctionType *FunTy = NULL;
1185  QualType PointeeTy = ExprTy->getPointeeType();
1186  if (!PointeeTy.isNull())
1187    FunTy = PointeeTy->getAs<FunctionType>();
1188  if (!FunTy)
1189    FunTy = ExprTy->getAs<FunctionType>();
1190  if (!FunTy && ExprTy == Context.BoundMemberTy) {
1191    // Look for the bound-member type.  If it's still overloaded, give up,
1192    // although we probably should have fallen into the OverloadExpr case above
1193    // if we actually have an overloaded bound member.
1194    QualType BoundMemberTy = Expr::findBoundMemberType(&E);
1195    if (!BoundMemberTy.isNull())
1196      FunTy = BoundMemberTy->castAs<FunctionType>();
1197  }
1198
1199  if (const FunctionProtoType *FPT =
1200      dyn_cast_or_null<FunctionProtoType>(FunTy)) {
1201    if (FPT->getNumArgs() == 0)
1202      ZeroArgCallReturnTy = FunTy->getResultType();
1203    return true;
1204  }
1205  return false;
1206}
1207
1208/// \brief Give notes for a set of overloads.
1209///
1210/// A companion to isExprCallable. In cases when the name that the programmer
1211/// wrote was an overloaded function, we may be able to make some guesses about
1212/// plausible overloads based on their return types; such guesses can be handed
1213/// off to this method to be emitted as notes.
1214///
1215/// \param Overloads - The overloads to note.
1216/// \param FinalNoteLoc - If we've suppressed printing some overloads due to
1217///  -fshow-overloads=best, this is the location to attach to the note about too
1218///  many candidates. Typically this will be the location of the original
1219///  ill-formed expression.
1220static void noteOverloads(Sema &S, const UnresolvedSetImpl &Overloads,
1221                          const SourceLocation FinalNoteLoc) {
1222  int ShownOverloads = 0;
1223  int SuppressedOverloads = 0;
1224  for (UnresolvedSetImpl::iterator It = Overloads.begin(),
1225       DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) {
1226    // FIXME: Magic number for max shown overloads stolen from
1227    // OverloadCandidateSet::NoteCandidates.
1228    if (ShownOverloads >= 4 && S.Diags.getShowOverloads() == Ovl_Best) {
1229      ++SuppressedOverloads;
1230      continue;
1231    }
1232
1233    NamedDecl *Fn = (*It)->getUnderlyingDecl();
1234    S.Diag(Fn->getLocation(), diag::note_possible_target_of_call);
1235    ++ShownOverloads;
1236  }
1237
1238  if (SuppressedOverloads)
1239    S.Diag(FinalNoteLoc, diag::note_ovl_too_many_candidates)
1240      << SuppressedOverloads;
1241}
1242
1243static void notePlausibleOverloads(Sema &S, SourceLocation Loc,
1244                                   const UnresolvedSetImpl &Overloads,
1245                                   bool (*IsPlausibleResult)(QualType)) {
1246  if (!IsPlausibleResult)
1247    return noteOverloads(S, Overloads, Loc);
1248
1249  UnresolvedSet<2> PlausibleOverloads;
1250  for (OverloadExpr::decls_iterator It = Overloads.begin(),
1251         DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) {
1252    const FunctionDecl *OverloadDecl = cast<FunctionDecl>(*It);
1253    QualType OverloadResultTy = OverloadDecl->getResultType();
1254    if (IsPlausibleResult(OverloadResultTy))
1255      PlausibleOverloads.addDecl(It.getDecl());
1256  }
1257  noteOverloads(S, PlausibleOverloads, Loc);
1258}
1259
1260/// Determine whether the given expression can be called by just
1261/// putting parentheses after it.  Notably, expressions with unary
1262/// operators can't be because the unary operator will start parsing
1263/// outside the call.
1264static bool IsCallableWithAppend(Expr *E) {
1265  E = E->IgnoreImplicit();
1266  return (!isa<CStyleCastExpr>(E) &&
1267          !isa<UnaryOperator>(E) &&
1268          !isa<BinaryOperator>(E) &&
1269          !isa<CXXOperatorCallExpr>(E));
1270}
1271
1272bool Sema::tryToRecoverWithCall(ExprResult &E, const PartialDiagnostic &PD,
1273                                bool ForceComplain,
1274                                bool (*IsPlausibleResult)(QualType)) {
1275  SourceLocation Loc = E.get()->getExprLoc();
1276  SourceRange Range = E.get()->getSourceRange();
1277
1278  QualType ZeroArgCallTy;
1279  UnresolvedSet<4> Overloads;
1280  if (isExprCallable(*E.get(), ZeroArgCallTy, Overloads) &&
1281      !ZeroArgCallTy.isNull() &&
1282      (!IsPlausibleResult || IsPlausibleResult(ZeroArgCallTy))) {
1283    // At this point, we know E is potentially callable with 0
1284    // arguments and that it returns something of a reasonable type,
1285    // so we can emit a fixit and carry on pretending that E was
1286    // actually a CallExpr.
1287    SourceLocation ParenInsertionLoc =
1288      PP.getLocForEndOfToken(Range.getEnd());
1289    Diag(Loc, PD)
1290      << /*zero-arg*/ 1 << Range
1291      << (IsCallableWithAppend(E.get())
1292          ? FixItHint::CreateInsertion(ParenInsertionLoc, "()")
1293          : FixItHint());
1294    notePlausibleOverloads(*this, Loc, Overloads, IsPlausibleResult);
1295
1296    // FIXME: Try this before emitting the fixit, and suppress diagnostics
1297    // while doing so.
1298    E = ActOnCallExpr(0, E.take(), ParenInsertionLoc,
1299                      MultiExprArg(), ParenInsertionLoc.getLocWithOffset(1));
1300    return true;
1301  }
1302
1303  if (!ForceComplain) return false;
1304
1305  Diag(Loc, PD) << /*not zero-arg*/ 0 << Range;
1306  notePlausibleOverloads(*this, Loc, Overloads, IsPlausibleResult);
1307  E = ExprError();
1308  return true;
1309}
1310
1311IdentifierInfo *Sema::getSuperIdentifier() const {
1312  if (!Ident_super)
1313    Ident_super = &Context.Idents.get("super");
1314  return Ident_super;
1315}
1316
1317void Sema::PushCapturedRegionScope(Scope *S, CapturedDecl *CD, RecordDecl *RD,
1318                                   CapturedRegionKind K) {
1319  CapturingScopeInfo *CSI = new CapturedRegionScopeInfo(getDiagnostics(), S, CD, RD,
1320                                                        CD->getContextParam(), K);
1321  CSI->ReturnType = Context.VoidTy;
1322  FunctionScopes.push_back(CSI);
1323}
1324
1325CapturedRegionScopeInfo *Sema::getCurCapturedRegion() {
1326  if (FunctionScopes.empty())
1327    return 0;
1328
1329  return dyn_cast<CapturedRegionScopeInfo>(FunctionScopes.back());
1330}
1331