Sema.cpp revision ddd2dfc1d3f4a36cbe8cd775c588623a17049f9f 
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), DisableTypoCorrection(false),
93    TyposCorrected(0), AnalysisWarnings(*this),
94    VarDataSharingAttributesStack(0), CurScope(0),
95    Ident_super(0), Ident___float128(0)
96{
97  TUScope = 0;
98
99  LoadedExternalKnownNamespaces = false;
100  for (unsigned I = 0; I != NSAPI::NumNSNumberLiteralMethods; ++I)
101    NSNumberLiteralMethods[I] = 0;
102
103  if (getLangOpts().ObjC1)
104    NSAPIObj.reset(new NSAPI(Context));
105
106  if (getLangOpts().CPlusPlus)
107    FieldCollector.reset(new CXXFieldCollector());
108
109  // Tell diagnostics how to render things from the AST library.
110  PP.getDiagnostics().SetArgToStringFn(&FormatASTNodeDiagnosticArgument,
111                                       &Context);
112
113  ExprEvalContexts.push_back(
114        ExpressionEvaluationContextRecord(PotentiallyEvaluated, 0,
115                                          false, 0, false));
116
117  FunctionScopes.push_back(new FunctionScopeInfo(Diags));
118
119  // Initilization of data sharing attributes stack for OpenMP
120  InitDataSharingAttributesStack();
121}
122
123void Sema::Initialize() {
124  // Tell the AST consumer about this Sema object.
125  Consumer.Initialize(Context);
126
127  // FIXME: Isn't this redundant with the initialization above?
128  if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
129    SC->InitializeSema(*this);
130
131  // Tell the external Sema source about this Sema object.
132  if (ExternalSemaSource *ExternalSema
133      = dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
134    ExternalSema->InitializeSema(*this);
135
136  // Initialize predefined 128-bit integer types, if needed.
137  if (PP.getTargetInfo().hasInt128Type()) {
138    // If either of the 128-bit integer types are unavailable to name lookup,
139    // define them now.
140    DeclarationName Int128 = &Context.Idents.get("__int128_t");
141    if (IdResolver.begin(Int128) == IdResolver.end())
142      PushOnScopeChains(Context.getInt128Decl(), TUScope);
143
144    DeclarationName UInt128 = &Context.Idents.get("__uint128_t");
145    if (IdResolver.begin(UInt128) == IdResolver.end())
146      PushOnScopeChains(Context.getUInt128Decl(), TUScope);
147  }
148
149
150  // Initialize predefined Objective-C types:
151  if (PP.getLangOpts().ObjC1) {
152    // If 'SEL' does not yet refer to any declarations, make it refer to the
153    // predefined 'SEL'.
154    DeclarationName SEL = &Context.Idents.get("SEL");
155    if (IdResolver.begin(SEL) == IdResolver.end())
156      PushOnScopeChains(Context.getObjCSelDecl(), TUScope);
157
158    // If 'id' does not yet refer to any declarations, make it refer to the
159    // predefined 'id'.
160    DeclarationName Id = &Context.Idents.get("id");
161    if (IdResolver.begin(Id) == IdResolver.end())
162      PushOnScopeChains(Context.getObjCIdDecl(), TUScope);
163
164    // Create the built-in typedef for 'Class'.
165    DeclarationName Class = &Context.Idents.get("Class");
166    if (IdResolver.begin(Class) == IdResolver.end())
167      PushOnScopeChains(Context.getObjCClassDecl(), TUScope);
168
169    // Create the built-in forward declaratino for 'Protocol'.
170    DeclarationName Protocol = &Context.Idents.get("Protocol");
171    if (IdResolver.begin(Protocol) == IdResolver.end())
172      PushOnScopeChains(Context.getObjCProtocolDecl(), TUScope);
173  }
174
175  DeclarationName BuiltinVaList = &Context.Idents.get("__builtin_va_list");
176  if (IdResolver.begin(BuiltinVaList) == IdResolver.end())
177    PushOnScopeChains(Context.getBuiltinVaListDecl(), TUScope);
178}
179
180Sema::~Sema() {
181  for (LateParsedTemplateMapT::iterator I = LateParsedTemplateMap.begin(),
182                                        E = LateParsedTemplateMap.end();
183       I != E; ++I)
184    delete I->second;
185  if (PackContext) FreePackedContext();
186  if (VisContext) FreeVisContext();
187  delete TheTargetAttributesSema;
188  MSStructPragmaOn = false;
189  // Kill all the active scopes.
190  for (unsigned I = 1, E = FunctionScopes.size(); I != E; ++I)
191    delete FunctionScopes[I];
192  if (FunctionScopes.size() == 1)
193    delete FunctionScopes[0];
194
195  // Tell the SemaConsumer to forget about us; we're going out of scope.
196  if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
197    SC->ForgetSema();
198
199  // Detach from the external Sema source.
200  if (ExternalSemaSource *ExternalSema
201        = dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
202    ExternalSema->ForgetSema();
203
204  // If Sema's ExternalSource is the multiplexer - we own it.
205  if (isMultiplexExternalSource)
206    delete ExternalSource;
207
208  // Destroys data sharing attributes stack for OpenMP
209  DestroyDataSharingAttributesStack();
210}
211
212/// makeUnavailableInSystemHeader - There is an error in the current
213/// context.  If we're still in a system header, and we can plausibly
214/// make the relevant declaration unavailable instead of erroring, do
215/// so and return true.
216bool Sema::makeUnavailableInSystemHeader(SourceLocation loc,
217                                         StringRef msg) {
218  // If we're not in a function, it's an error.
219  FunctionDecl *fn = dyn_cast<FunctionDecl>(CurContext);
220  if (!fn) return false;
221
222  // If we're in template instantiation, it's an error.
223  if (!ActiveTemplateInstantiations.empty())
224    return false;
225
226  // If that function's not in a system header, it's an error.
227  if (!Context.getSourceManager().isInSystemHeader(loc))
228    return false;
229
230  // If the function is already unavailable, it's not an error.
231  if (fn->hasAttr<UnavailableAttr>()) return true;
232
233  fn->addAttr(new (Context) UnavailableAttr(loc, Context, msg));
234  return true;
235}
236
237ASTMutationListener *Sema::getASTMutationListener() const {
238  return getASTConsumer().GetASTMutationListener();
239}
240
241///\brief Registers an external source. If an external source already exists,
242/// creates a multiplex external source and appends to it.
243///
244///\param[in] E - A non-null external sema source.
245///
246void Sema::addExternalSource(ExternalSemaSource *E) {
247  assert(E && "Cannot use with NULL ptr");
248
249  if (!ExternalSource) {
250    ExternalSource = E;
251    return;
252  }
253
254  if (isMultiplexExternalSource)
255    static_cast<MultiplexExternalSemaSource*>(ExternalSource)->addSource(*E);
256  else {
257    ExternalSource = new MultiplexExternalSemaSource(*ExternalSource, *E);
258    isMultiplexExternalSource = true;
259  }
260}
261
262/// \brief Print out statistics about the semantic analysis.
263void Sema::PrintStats() const {
264  llvm::errs() << "\n*** Semantic Analysis Stats:\n";
265  llvm::errs() << NumSFINAEErrors << " SFINAE diagnostics trapped.\n";
266
267  BumpAlloc.PrintStats();
268  AnalysisWarnings.PrintStats();
269}
270
271/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast.
272/// If there is already an implicit cast, merge into the existing one.
273/// The result is of the given category.
274ExprResult Sema::ImpCastExprToType(Expr *E, QualType Ty,
275                                   CastKind Kind, ExprValueKind VK,
276                                   const CXXCastPath *BasePath,
277                                   CheckedConversionKind CCK) {
278#ifndef NDEBUG
279  if (VK == VK_RValue && !E->isRValue()) {
280    switch (Kind) {
281    default:
282      assert(0 && "can't implicitly cast lvalue to rvalue with this cast kind");
283    case CK_LValueToRValue:
284    case CK_ArrayToPointerDecay:
285    case CK_FunctionToPointerDecay:
286    case CK_ToVoid:
287      break;
288    }
289  }
290  assert((VK == VK_RValue || !E->isRValue()) && "can't cast rvalue to lvalue");
291#endif
292
293  QualType ExprTy = Context.getCanonicalType(E->getType());
294  QualType TypeTy = Context.getCanonicalType(Ty);
295
296  if (ExprTy == TypeTy)
297    return Owned(E);
298
299  // If this is a derived-to-base cast to a through a virtual base, we
300  // need a vtable.
301  if (Kind == CK_DerivedToBase &&
302      BasePathInvolvesVirtualBase(*BasePath)) {
303    QualType T = E->getType();
304    if (const PointerType *Pointer = T->getAs<PointerType>())
305      T = Pointer->getPointeeType();
306    if (const RecordType *RecordTy = T->getAs<RecordType>())
307      MarkVTableUsed(E->getLocStart(),
308                     cast<CXXRecordDecl>(RecordTy->getDecl()));
309  }
310
311  if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(E)) {
312    if (ImpCast->getCastKind() == Kind && (!BasePath || BasePath->empty())) {
313      ImpCast->setType(Ty);
314      ImpCast->setValueKind(VK);
315      return Owned(E);
316    }
317  }
318
319  return Owned(ImplicitCastExpr::Create(Context, Ty, Kind, E, BasePath, VK));
320}
321
322/// ScalarTypeToBooleanCastKind - Returns the cast kind corresponding
323/// to the conversion from scalar type ScalarTy to the Boolean type.
324CastKind Sema::ScalarTypeToBooleanCastKind(QualType ScalarTy) {
325  switch (ScalarTy->getScalarTypeKind()) {
326  case Type::STK_Bool: return CK_NoOp;
327  case Type::STK_CPointer: return CK_PointerToBoolean;
328  case Type::STK_BlockPointer: return CK_PointerToBoolean;
329  case Type::STK_ObjCObjectPointer: return CK_PointerToBoolean;
330  case Type::STK_MemberPointer: return CK_MemberPointerToBoolean;
331  case Type::STK_Integral: return CK_IntegralToBoolean;
332  case Type::STK_Floating: return CK_FloatingToBoolean;
333  case Type::STK_IntegralComplex: return CK_IntegralComplexToBoolean;
334  case Type::STK_FloatingComplex: return CK_FloatingComplexToBoolean;
335  }
336  return CK_Invalid;
337}
338
339/// \brief Used to prune the decls of Sema's UnusedFileScopedDecls vector.
340static bool ShouldRemoveFromUnused(Sema *SemaRef, const DeclaratorDecl *D) {
341  if (D->getMostRecentDecl()->isUsed())
342    return true;
343
344  if (D->isExternallyVisible())
345    return true;
346
347  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
348    // UnusedFileScopedDecls stores the first declaration.
349    // The declaration may have become definition so check again.
350    const FunctionDecl *DeclToCheck;
351    if (FD->hasBody(DeclToCheck))
352      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
353
354    // Later redecls may add new information resulting in not having to warn,
355    // so check again.
356    DeclToCheck = FD->getMostRecentDecl();
357    if (DeclToCheck != FD)
358      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
359  }
360
361  if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
362    // If a variable usable in constant expressions is referenced,
363    // don't warn if it isn't used: if the value of a variable is required
364    // for the computation of a constant expression, it doesn't make sense to
365    // warn even if the variable isn't odr-used.  (isReferenced doesn't
366    // precisely reflect that, but it's a decent approximation.)
367    if (VD->isReferenced() &&
368        VD->isUsableInConstantExpressions(SemaRef->Context))
369      return true;
370
371    // UnusedFileScopedDecls stores the first declaration.
372    // The declaration may have become definition so check again.
373    const VarDecl *DeclToCheck = VD->getDefinition();
374    if (DeclToCheck)
375      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
376
377    // Later redecls may add new information resulting in not having to warn,
378    // so check again.
379    DeclToCheck = VD->getMostRecentDecl();
380    if (DeclToCheck != VD)
381      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
382  }
383
384  return false;
385}
386
387namespace {
388  struct SortUndefinedButUsed {
389    const SourceManager &SM;
390    explicit SortUndefinedButUsed(SourceManager &SM) : SM(SM) {}
391
392    bool operator()(const std::pair<NamedDecl *, SourceLocation> &l,
393                    const std::pair<NamedDecl *, SourceLocation> &r) const {
394      if (l.second.isValid() && !r.second.isValid())
395        return true;
396      if (!l.second.isValid() && r.second.isValid())
397        return false;
398      if (l.second != r.second)
399        return SM.isBeforeInTranslationUnit(l.second, r.second);
400      return SM.isBeforeInTranslationUnit(l.first->getLocation(),
401                                          r.first->getLocation());
402    }
403  };
404}
405
406/// Obtains a sorted list of functions that are undefined but ODR-used.
407void Sema::getUndefinedButUsed(
408    SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> > &Undefined) {
409  for (llvm::DenseMap<NamedDecl *, SourceLocation>::iterator
410         I = UndefinedButUsed.begin(), E = UndefinedButUsed.end();
411       I != E; ++I) {
412    NamedDecl *ND = I->first;
413
414    // Ignore attributes that have become invalid.
415    if (ND->isInvalidDecl()) continue;
416
417    // __attribute__((weakref)) is basically a definition.
418    if (ND->hasAttr<WeakRefAttr>()) continue;
419
420    if (FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
421      if (FD->isDefined())
422        continue;
423      if (FD->isExternallyVisible() &&
424          !FD->getMostRecentDecl()->isInlined())
425        continue;
426    } else {
427      if (cast<VarDecl>(ND)->hasDefinition() != VarDecl::DeclarationOnly)
428        continue;
429      if (ND->isExternallyVisible())
430        continue;
431    }
432
433    Undefined.push_back(std::make_pair(ND, I->second));
434  }
435
436  // Sort (in order of use site) so that we're not dependent on the iteration
437  // order through an llvm::DenseMap.
438  std::sort(Undefined.begin(), Undefined.end(),
439            SortUndefinedButUsed(Context.getSourceManager()));
440}
441
442/// checkUndefinedButUsed - Check for undefined objects with internal linkage
443/// or that are inline.
444static void checkUndefinedButUsed(Sema &S) {
445  if (S.UndefinedButUsed.empty()) return;
446
447  // Collect all the still-undefined entities with internal linkage.
448  SmallVector<std::pair<NamedDecl *, SourceLocation>, 16> Undefined;
449  S.getUndefinedButUsed(Undefined);
450  if (Undefined.empty()) return;
451
452  for (SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> >::iterator
453         I = Undefined.begin(), E = Undefined.end(); I != E; ++I) {
454    NamedDecl *ND = I->first;
455
456    if (!ND->isExternallyVisible()) {
457      S.Diag(ND->getLocation(), diag::warn_undefined_internal)
458        << isa<VarDecl>(ND) << ND;
459    } else {
460      assert(cast<FunctionDecl>(ND)->getMostRecentDecl()->isInlined() &&
461             "used object requires definition but isn't inline or internal?");
462      S.Diag(ND->getLocation(), diag::warn_undefined_inline) << ND;
463    }
464    if (I->second.isValid())
465      S.Diag(I->second, diag::note_used_here);
466  }
467}
468
469void Sema::LoadExternalWeakUndeclaredIdentifiers() {
470  if (!ExternalSource)
471    return;
472
473  SmallVector<std::pair<IdentifierInfo *, WeakInfo>, 4> WeakIDs;
474  ExternalSource->ReadWeakUndeclaredIdentifiers(WeakIDs);
475  for (unsigned I = 0, N = WeakIDs.size(); I != N; ++I) {
476    llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator Pos
477      = WeakUndeclaredIdentifiers.find(WeakIDs[I].first);
478    if (Pos != WeakUndeclaredIdentifiers.end())
479      continue;
480
481    WeakUndeclaredIdentifiers.insert(WeakIDs[I]);
482  }
483}
484
485
486typedef llvm::DenseMap<const CXXRecordDecl*, bool> RecordCompleteMap;
487
488/// \brief Returns true, if all methods and nested classes of the given
489/// CXXRecordDecl are defined in this translation unit.
490///
491/// Should only be called from ActOnEndOfTranslationUnit so that all
492/// definitions are actually read.
493static bool MethodsAndNestedClassesComplete(const CXXRecordDecl *RD,
494                                            RecordCompleteMap &MNCComplete) {
495  RecordCompleteMap::iterator Cache = MNCComplete.find(RD);
496  if (Cache != MNCComplete.end())
497    return Cache->second;
498  if (!RD->isCompleteDefinition())
499    return false;
500  bool Complete = true;
501  for (DeclContext::decl_iterator I = RD->decls_begin(),
502                                  E = RD->decls_end();
503       I != E && Complete; ++I) {
504    if (const CXXMethodDecl *M = dyn_cast<CXXMethodDecl>(*I))
505      Complete = M->isDefined() || (M->isPure() && !isa<CXXDestructorDecl>(M));
506    else if (const FunctionTemplateDecl *F = dyn_cast<FunctionTemplateDecl>(*I))
507      Complete = F->getTemplatedDecl()->isDefined();
508    else if (const CXXRecordDecl *R = dyn_cast<CXXRecordDecl>(*I)) {
509      if (R->isInjectedClassName())
510        continue;
511      if (R->hasDefinition())
512        Complete = MethodsAndNestedClassesComplete(R->getDefinition(),
513                                                   MNCComplete);
514      else
515        Complete = false;
516    }
517  }
518  MNCComplete[RD] = Complete;
519  return Complete;
520}
521
522/// \brief Returns true, if the given CXXRecordDecl is fully defined in this
523/// translation unit, i.e. all methods are defined or pure virtual and all
524/// friends, friend functions and nested classes are fully defined in this
525/// translation unit.
526///
527/// Should only be called from ActOnEndOfTranslationUnit so that all
528/// definitions are actually read.
529static bool IsRecordFullyDefined(const CXXRecordDecl *RD,
530                                 RecordCompleteMap &RecordsComplete,
531                                 RecordCompleteMap &MNCComplete) {
532  RecordCompleteMap::iterator Cache = RecordsComplete.find(RD);
533  if (Cache != RecordsComplete.end())
534    return Cache->second;
535  bool Complete = MethodsAndNestedClassesComplete(RD, MNCComplete);
536  for (CXXRecordDecl::friend_iterator I = RD->friend_begin(),
537                                      E = RD->friend_end();
538       I != E && Complete; ++I) {
539    // Check if friend classes and methods are complete.
540    if (TypeSourceInfo *TSI = (*I)->getFriendType()) {
541      // Friend classes are available as the TypeSourceInfo of the FriendDecl.
542      if (CXXRecordDecl *FriendD = TSI->getType()->getAsCXXRecordDecl())
543        Complete = MethodsAndNestedClassesComplete(FriendD, MNCComplete);
544      else
545        Complete = false;
546    } else {
547      // Friend functions are available through the NamedDecl of FriendDecl.
548      if (const FunctionDecl *FD =
549          dyn_cast<FunctionDecl>((*I)->getFriendDecl()))
550        Complete = FD->isDefined();
551      else
552        // This is a template friend, give up.
553        Complete = false;
554    }
555  }
556  RecordsComplete[RD] = Complete;
557  return Complete;
558}
559
560/// ActOnEndOfTranslationUnit - This is called at the very end of the
561/// translation unit when EOF is reached and all but the top-level scope is
562/// popped.
563void Sema::ActOnEndOfTranslationUnit() {
564  assert(DelayedDiagnostics.getCurrentPool() == NULL
565         && "reached end of translation unit with a pool attached?");
566
567  // If code completion is enabled, don't perform any end-of-translation-unit
568  // work.
569  if (PP.isCodeCompletionEnabled())
570    return;
571
572  // Complete translation units and modules define vtables and perform implicit
573  // instantiations. PCH files do not.
574  if (TUKind != TU_Prefix) {
575    DiagnoseUseOfUnimplementedSelectors();
576
577    // If any dynamic classes have their key function defined within
578    // this translation unit, then those vtables are considered "used" and must
579    // be emitted.
580    for (DynamicClassesType::iterator I = DynamicClasses.begin(ExternalSource),
581                                      E = DynamicClasses.end();
582         I != E; ++I) {
583      assert(!(*I)->isDependentType() &&
584             "Should not see dependent types here!");
585      if (const CXXMethodDecl *KeyFunction = Context.getCurrentKeyFunction(*I)) {
586        const FunctionDecl *Definition = 0;
587        if (KeyFunction->hasBody(Definition))
588          MarkVTableUsed(Definition->getLocation(), *I, true);
589      }
590    }
591
592    // If DefinedUsedVTables ends up marking any virtual member functions it
593    // might lead to more pending template instantiations, which we then need
594    // to instantiate.
595    DefineUsedVTables();
596
597    // C++: Perform implicit template instantiations.
598    //
599    // FIXME: When we perform these implicit instantiations, we do not
600    // carefully keep track of the point of instantiation (C++ [temp.point]).
601    // This means that name lookup that occurs within the template
602    // instantiation will always happen at the end of the translation unit,
603    // so it will find some names that are not required to be found. This is
604    // valid, but we could do better by diagnosing if an instantiation uses a
605    // name that was not visible at its first point of instantiation.
606    PerformPendingInstantiations();
607  }
608
609  // Remove file scoped decls that turned out to be used.
610  UnusedFileScopedDecls.erase(
611      std::remove_if(UnusedFileScopedDecls.begin(0, true),
612                     UnusedFileScopedDecls.end(),
613                     std::bind1st(std::ptr_fun(ShouldRemoveFromUnused), this)),
614      UnusedFileScopedDecls.end());
615
616  if (TUKind == TU_Prefix) {
617    // Translation unit prefixes don't need any of the checking below.
618    TUScope = 0;
619    return;
620  }
621
622  // Check for #pragma weak identifiers that were never declared
623  // FIXME: This will cause diagnostics to be emitted in a non-determinstic
624  // order!  Iterating over a densemap like this is bad.
625  LoadExternalWeakUndeclaredIdentifiers();
626  for (llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator
627       I = WeakUndeclaredIdentifiers.begin(),
628       E = WeakUndeclaredIdentifiers.end(); I != E; ++I) {
629    if (I->second.getUsed()) continue;
630
631    Diag(I->second.getLocation(), diag::warn_weak_identifier_undeclared)
632      << I->first;
633  }
634
635  if (LangOpts.CPlusPlus11 &&
636      Diags.getDiagnosticLevel(diag::warn_delegating_ctor_cycle,
637                               SourceLocation())
638        != DiagnosticsEngine::Ignored)
639    CheckDelegatingCtorCycles();
640
641  if (TUKind == TU_Module) {
642    // If we are building a module, resolve all of the exported declarations
643    // now.
644    if (Module *CurrentModule = PP.getCurrentModule()) {
645      ModuleMap &ModMap = PP.getHeaderSearchInfo().getModuleMap();
646
647      SmallVector<Module *, 2> Stack;
648      Stack.push_back(CurrentModule);
649      while (!Stack.empty()) {
650        Module *Mod = Stack.pop_back_val();
651
652        // Resolve the exported declarations and conflicts.
653        // FIXME: Actually complain, once we figure out how to teach the
654        // diagnostic client to deal with complaints in the module map at this
655        // point.
656        ModMap.resolveExports(Mod, /*Complain=*/false);
657        ModMap.resolveUses(Mod, /*Complain=*/false);
658        ModMap.resolveConflicts(Mod, /*Complain=*/false);
659
660        // Queue the submodules, so their exports will also be resolved.
661        for (Module::submodule_iterator Sub = Mod->submodule_begin(),
662                                     SubEnd = Mod->submodule_end();
663             Sub != SubEnd; ++Sub) {
664          Stack.push_back(*Sub);
665        }
666      }
667    }
668
669    // Modules don't need any of the checking below.
670    TUScope = 0;
671    return;
672  }
673
674  // C99 6.9.2p2:
675  //   A declaration of an identifier for an object that has file
676  //   scope without an initializer, and without a storage-class
677  //   specifier or with the storage-class specifier static,
678  //   constitutes a tentative definition. If a translation unit
679  //   contains one or more tentative definitions for an identifier,
680  //   and the translation unit contains no external definition for
681  //   that identifier, then the behavior is exactly as if the
682  //   translation unit contains a file scope declaration of that
683  //   identifier, with the composite type as of the end of the
684  //   translation unit, with an initializer equal to 0.
685  llvm::SmallSet<VarDecl *, 32> Seen;
686  for (TentativeDefinitionsType::iterator
687            T = TentativeDefinitions.begin(ExternalSource),
688         TEnd = TentativeDefinitions.end();
689       T != TEnd; ++T)
690  {
691    VarDecl *VD = (*T)->getActingDefinition();
692
693    // If the tentative definition was completed, getActingDefinition() returns
694    // null. If we've already seen this variable before, insert()'s second
695    // return value is false.
696    if (VD == 0 || VD->isInvalidDecl() || !Seen.insert(VD))
697      continue;
698
699    if (const IncompleteArrayType *ArrayT
700        = Context.getAsIncompleteArrayType(VD->getType())) {
701      // Set the length of the array to 1 (C99 6.9.2p5).
702      Diag(VD->getLocation(), diag::warn_tentative_incomplete_array);
703      llvm::APInt One(Context.getTypeSize(Context.getSizeType()), true);
704      QualType T = Context.getConstantArrayType(ArrayT->getElementType(),
705                                                One, ArrayType::Normal, 0);
706      VD->setType(T);
707    } else if (RequireCompleteType(VD->getLocation(), VD->getType(),
708                                   diag::err_tentative_def_incomplete_type))
709      VD->setInvalidDecl();
710
711    CheckCompleteVariableDeclaration(VD);
712
713    // Notify the consumer that we've completed a tentative definition.
714    if (!VD->isInvalidDecl())
715      Consumer.CompleteTentativeDefinition(VD);
716
717  }
718
719  // If there were errors, disable 'unused' warnings since they will mostly be
720  // noise.
721  if (!Diags.hasErrorOccurred()) {
722    // Output warning for unused file scoped decls.
723    for (UnusedFileScopedDeclsType::iterator
724           I = UnusedFileScopedDecls.begin(ExternalSource),
725           E = UnusedFileScopedDecls.end(); I != E; ++I) {
726      if (ShouldRemoveFromUnused(this, *I))
727        continue;
728
729      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) {
730        const FunctionDecl *DiagD;
731        if (!FD->hasBody(DiagD))
732          DiagD = FD;
733        if (DiagD->isDeleted())
734          continue; // Deleted functions are supposed to be unused.
735        if (DiagD->isReferenced()) {
736          if (isa<CXXMethodDecl>(DiagD))
737            Diag(DiagD->getLocation(), diag::warn_unneeded_member_function)
738                  << DiagD->getDeclName();
739          else {
740            if (FD->getStorageClass() == SC_Static &&
741                !FD->isInlineSpecified() &&
742                !SourceMgr.isInMainFile(
743                   SourceMgr.getExpansionLoc(FD->getLocation())))
744              Diag(DiagD->getLocation(), diag::warn_unneeded_static_internal_decl)
745                << DiagD->getDeclName();
746            else
747              Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
748                   << /*function*/0 << DiagD->getDeclName();
749          }
750        } else {
751          Diag(DiagD->getLocation(),
752               isa<CXXMethodDecl>(DiagD) ? diag::warn_unused_member_function
753                                         : diag::warn_unused_function)
754                << DiagD->getDeclName();
755        }
756      } else {
757        const VarDecl *DiagD = cast<VarDecl>(*I)->getDefinition();
758        if (!DiagD)
759          DiagD = cast<VarDecl>(*I);
760        if (DiagD->isReferenced()) {
761          Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
762                << /*variable*/1 << DiagD->getDeclName();
763        } else if (DiagD->getType().isConstQualified()) {
764          Diag(DiagD->getLocation(), diag::warn_unused_const_variable)
765              << DiagD->getDeclName();
766        } else {
767          Diag(DiagD->getLocation(), diag::warn_unused_variable)
768              << DiagD->getDeclName();
769        }
770      }
771    }
772
773    if (ExternalSource)
774      ExternalSource->ReadUndefinedButUsed(UndefinedButUsed);
775    checkUndefinedButUsed(*this);
776  }
777
778  if (Diags.getDiagnosticLevel(diag::warn_unused_private_field,
779                               SourceLocation())
780        != DiagnosticsEngine::Ignored) {
781    RecordCompleteMap RecordsComplete;
782    RecordCompleteMap MNCComplete;
783    for (NamedDeclSetType::iterator I = UnusedPrivateFields.begin(),
784         E = UnusedPrivateFields.end(); I != E; ++I) {
785      const NamedDecl *D = *I;
786      const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D->getDeclContext());
787      if (RD && !RD->isUnion() &&
788          IsRecordFullyDefined(RD, RecordsComplete, MNCComplete)) {
789        Diag(D->getLocation(), diag::warn_unused_private_field)
790              << D->getDeclName();
791      }
792    }
793  }
794
795  // Check we've noticed that we're no longer parsing the initializer for every
796  // variable. If we miss cases, then at best we have a performance issue and
797  // at worst a rejects-valid bug.
798  assert(ParsingInitForAutoVars.empty() &&
799         "Didn't unmark var as having its initializer parsed");
800
801  TUScope = 0;
802}
803
804
805//===----------------------------------------------------------------------===//
806// Helper functions.
807//===----------------------------------------------------------------------===//
808
809DeclContext *Sema::getFunctionLevelDeclContext() {
810  DeclContext *DC = CurContext;
811
812  while (true) {
813    if (isa<BlockDecl>(DC) || isa<EnumDecl>(DC) || isa<CapturedDecl>(DC)) {
814      DC = DC->getParent();
815    } else if (isa<CXXMethodDecl>(DC) &&
816               cast<CXXMethodDecl>(DC)->getOverloadedOperator() == OO_Call &&
817               cast<CXXRecordDecl>(DC->getParent())->isLambda()) {
818      DC = DC->getParent()->getParent();
819    }
820    else break;
821  }
822
823  return DC;
824}
825
826/// getCurFunctionDecl - If inside of a function body, this returns a pointer
827/// to the function decl for the function being parsed.  If we're currently
828/// in a 'block', this returns the containing context.
829FunctionDecl *Sema::getCurFunctionDecl() {
830  DeclContext *DC = getFunctionLevelDeclContext();
831  return dyn_cast<FunctionDecl>(DC);
832}
833
834ObjCMethodDecl *Sema::getCurMethodDecl() {
835  DeclContext *DC = getFunctionLevelDeclContext();
836  while (isa<RecordDecl>(DC))
837    DC = DC->getParent();
838  return dyn_cast<ObjCMethodDecl>(DC);
839}
840
841NamedDecl *Sema::getCurFunctionOrMethodDecl() {
842  DeclContext *DC = getFunctionLevelDeclContext();
843  if (isa<ObjCMethodDecl>(DC) || isa<FunctionDecl>(DC))
844    return cast<NamedDecl>(DC);
845  return 0;
846}
847
848void Sema::EmitCurrentDiagnostic(unsigned DiagID) {
849  // FIXME: It doesn't make sense to me that DiagID is an incoming argument here
850  // and yet we also use the current diag ID on the DiagnosticsEngine. This has
851  // been made more painfully obvious by the refactor that introduced this
852  // function, but it is possible that the incoming argument can be
853  // eliminnated. If it truly cannot be (for example, there is some reentrancy
854  // issue I am not seeing yet), then there should at least be a clarifying
855  // comment somewhere.
856  if (Optional<TemplateDeductionInfo*> Info = isSFINAEContext()) {
857    switch (DiagnosticIDs::getDiagnosticSFINAEResponse(
858              Diags.getCurrentDiagID())) {
859    case DiagnosticIDs::SFINAE_Report:
860      // We'll report the diagnostic below.
861      break;
862
863    case DiagnosticIDs::SFINAE_SubstitutionFailure:
864      // Count this failure so that we know that template argument deduction
865      // has failed.
866      ++NumSFINAEErrors;
867
868      // Make a copy of this suppressed diagnostic and store it with the
869      // template-deduction information.
870      if (*Info && !(*Info)->hasSFINAEDiagnostic()) {
871        Diagnostic DiagInfo(&Diags);
872        (*Info)->addSFINAEDiagnostic(DiagInfo.getLocation(),
873                       PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
874      }
875
876      Diags.setLastDiagnosticIgnored();
877      Diags.Clear();
878      return;
879
880    case DiagnosticIDs::SFINAE_AccessControl: {
881      // Per C++ Core Issue 1170, access control is part of SFINAE.
882      // Additionally, the AccessCheckingSFINAE flag can be used to temporarily
883      // make access control a part of SFINAE for the purposes of checking
884      // type traits.
885      if (!AccessCheckingSFINAE && !getLangOpts().CPlusPlus11)
886        break;
887
888      SourceLocation Loc = Diags.getCurrentDiagLoc();
889
890      // Suppress this diagnostic.
891      ++NumSFINAEErrors;
892
893      // Make a copy of this suppressed diagnostic and store it with the
894      // template-deduction information.
895      if (*Info && !(*Info)->hasSFINAEDiagnostic()) {
896        Diagnostic DiagInfo(&Diags);
897        (*Info)->addSFINAEDiagnostic(DiagInfo.getLocation(),
898                       PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
899      }
900
901      Diags.setLastDiagnosticIgnored();
902      Diags.Clear();
903
904      // Now the diagnostic state is clear, produce a C++98 compatibility
905      // warning.
906      Diag(Loc, diag::warn_cxx98_compat_sfinae_access_control);
907
908      // The last diagnostic which Sema produced was ignored. Suppress any
909      // notes attached to it.
910      Diags.setLastDiagnosticIgnored();
911      return;
912    }
913
914    case DiagnosticIDs::SFINAE_Suppress:
915      // Make a copy of this suppressed diagnostic and store it with the
916      // template-deduction information;
917      if (*Info) {
918        Diagnostic DiagInfo(&Diags);
919        (*Info)->addSuppressedDiagnostic(DiagInfo.getLocation(),
920                       PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
921      }
922
923      // Suppress this diagnostic.
924      Diags.setLastDiagnosticIgnored();
925      Diags.Clear();
926      return;
927    }
928  }
929
930  // Set up the context's printing policy based on our current state.
931  Context.setPrintingPolicy(getPrintingPolicy());
932
933  // Emit the diagnostic.
934  if (!Diags.EmitCurrentDiagnostic())
935    return;
936
937  // If this is not a note, and we're in a template instantiation
938  // that is different from the last template instantiation where
939  // we emitted an error, print a template instantiation
940  // backtrace.
941  if (!DiagnosticIDs::isBuiltinNote(DiagID) &&
942      !ActiveTemplateInstantiations.empty() &&
943      ActiveTemplateInstantiations.back()
944        != LastTemplateInstantiationErrorContext) {
945    PrintInstantiationStack();
946    LastTemplateInstantiationErrorContext = ActiveTemplateInstantiations.back();
947  }
948}
949
950Sema::SemaDiagnosticBuilder
951Sema::Diag(SourceLocation Loc, const PartialDiagnostic& PD) {
952  SemaDiagnosticBuilder Builder(Diag(Loc, PD.getDiagID()));
953  PD.Emit(Builder);
954
955  return Builder;
956}
957
958/// \brief Looks through the macro-expansion chain for the given
959/// location, looking for a macro expansion with the given name.
960/// If one is found, returns true and sets the location to that
961/// expansion loc.
962bool Sema::findMacroSpelling(SourceLocation &locref, StringRef name) {
963  SourceLocation loc = locref;
964  if (!loc.isMacroID()) return false;
965
966  // There's no good way right now to look at the intermediate
967  // expansions, so just jump to the expansion location.
968  loc = getSourceManager().getExpansionLoc(loc);
969
970  // If that's written with the name, stop here.
971  SmallVector<char, 16> buffer;
972  if (getPreprocessor().getSpelling(loc, buffer) == name) {
973    locref = loc;
974    return true;
975  }
976  return false;
977}
978
979/// \brief Determines the active Scope associated with the given declaration
980/// context.
981///
982/// This routine maps a declaration context to the active Scope object that
983/// represents that declaration context in the parser. It is typically used
984/// from "scope-less" code (e.g., template instantiation, lazy creation of
985/// declarations) that injects a name for name-lookup purposes and, therefore,
986/// must update the Scope.
987///
988/// \returns The scope corresponding to the given declaraion context, or NULL
989/// if no such scope is open.
990Scope *Sema::getScopeForContext(DeclContext *Ctx) {
991
992  if (!Ctx)
993    return 0;
994
995  Ctx = Ctx->getPrimaryContext();
996  for (Scope *S = getCurScope(); S; S = S->getParent()) {
997    // Ignore scopes that cannot have declarations. This is important for
998    // out-of-line definitions of static class members.
999    if (S->getFlags() & (Scope::DeclScope | Scope::TemplateParamScope))
1000      if (DeclContext *Entity = static_cast<DeclContext *> (S->getEntity()))
1001        if (Ctx == Entity->getPrimaryContext())
1002          return S;
1003  }
1004
1005  return 0;
1006}
1007
1008/// \brief Enter a new function scope
1009void Sema::PushFunctionScope() {
1010  if (FunctionScopes.size() == 1) {
1011    // Use the "top" function scope rather than having to allocate
1012    // memory for a new scope.
1013    FunctionScopes.back()->Clear();
1014    FunctionScopes.push_back(FunctionScopes.back());
1015    return;
1016  }
1017
1018  FunctionScopes.push_back(new FunctionScopeInfo(getDiagnostics()));
1019}
1020
1021void Sema::PushBlockScope(Scope *BlockScope, BlockDecl *Block) {
1022  FunctionScopes.push_back(new BlockScopeInfo(getDiagnostics(),
1023                                              BlockScope, Block));
1024}
1025
1026void Sema::PushLambdaScope(CXXRecordDecl *Lambda,
1027                           CXXMethodDecl *CallOperator) {
1028  FunctionScopes.push_back(new LambdaScopeInfo(getDiagnostics(), Lambda,
1029                                               CallOperator));
1030}
1031
1032void Sema::PopFunctionScopeInfo(const AnalysisBasedWarnings::Policy *WP,
1033                                const Decl *D, const BlockExpr *blkExpr) {
1034  FunctionScopeInfo *Scope = FunctionScopes.pop_back_val();
1035  assert(!FunctionScopes.empty() && "mismatched push/pop!");
1036
1037  // Issue any analysis-based warnings.
1038  if (WP && D)
1039    AnalysisWarnings.IssueWarnings(*WP, Scope, D, blkExpr);
1040  else {
1041    for (SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator
1042         i = Scope->PossiblyUnreachableDiags.begin(),
1043         e = Scope->PossiblyUnreachableDiags.end();
1044         i != e; ++i) {
1045      const sema::PossiblyUnreachableDiag &D = *i;
1046      Diag(D.Loc, D.PD);
1047    }
1048  }
1049
1050  if (FunctionScopes.back() != Scope) {
1051    delete Scope;
1052  }
1053}
1054
1055void Sema::PushCompoundScope() {
1056  getCurFunction()->CompoundScopes.push_back(CompoundScopeInfo());
1057}
1058
1059void Sema::PopCompoundScope() {
1060  FunctionScopeInfo *CurFunction = getCurFunction();
1061  assert(!CurFunction->CompoundScopes.empty() && "mismatched push/pop");
1062
1063  CurFunction->CompoundScopes.pop_back();
1064}
1065
1066/// \brief Determine whether any errors occurred within this function/method/
1067/// block.
1068bool Sema::hasAnyUnrecoverableErrorsInThisFunction() const {
1069  return getCurFunction()->ErrorTrap.hasUnrecoverableErrorOccurred();
1070}
1071
1072BlockScopeInfo *Sema::getCurBlock() {
1073  if (FunctionScopes.empty())
1074    return 0;
1075
1076  return dyn_cast<BlockScopeInfo>(FunctionScopes.back());
1077}
1078
1079LambdaScopeInfo *Sema::getCurLambda() {
1080  if (FunctionScopes.empty())
1081    return 0;
1082
1083  return dyn_cast<LambdaScopeInfo>(FunctionScopes.back());
1084}
1085
1086void Sema::ActOnComment(SourceRange Comment) {
1087  if (!LangOpts.RetainCommentsFromSystemHeaders &&
1088      SourceMgr.isInSystemHeader(Comment.getBegin()))
1089    return;
1090  RawComment RC(SourceMgr, Comment, false,
1091                LangOpts.CommentOpts.ParseAllComments);
1092  if (RC.isAlmostTrailingComment()) {
1093    SourceRange MagicMarkerRange(Comment.getBegin(),
1094                                 Comment.getBegin().getLocWithOffset(3));
1095    StringRef MagicMarkerText;
1096    switch (RC.getKind()) {
1097    case RawComment::RCK_OrdinaryBCPL:
1098      MagicMarkerText = "///<";
1099      break;
1100    case RawComment::RCK_OrdinaryC:
1101      MagicMarkerText = "/**<";
1102      break;
1103    default:
1104      llvm_unreachable("if this is an almost Doxygen comment, "
1105                       "it should be ordinary");
1106    }
1107    Diag(Comment.getBegin(), diag::warn_not_a_doxygen_trailing_member_comment) <<
1108      FixItHint::CreateReplacement(MagicMarkerRange, MagicMarkerText);
1109  }
1110  Context.addComment(RC);
1111}
1112
1113// Pin this vtable to this file.
1114ExternalSemaSource::~ExternalSemaSource() {}
1115
1116void ExternalSemaSource::ReadMethodPool(Selector Sel) { }
1117
1118void ExternalSemaSource::ReadKnownNamespaces(
1119                           SmallVectorImpl<NamespaceDecl *> &Namespaces) {
1120}
1121
1122void ExternalSemaSource::ReadUndefinedButUsed(
1123                       llvm::DenseMap<NamedDecl *, SourceLocation> &Undefined) {
1124}
1125
1126void PrettyDeclStackTraceEntry::print(raw_ostream &OS) const {
1127  SourceLocation Loc = this->Loc;
1128  if (!Loc.isValid() && TheDecl) Loc = TheDecl->getLocation();
1129  if (Loc.isValid()) {
1130    Loc.print(OS, S.getSourceManager());
1131    OS << ": ";
1132  }
1133  OS << Message;
1134
1135  if (TheDecl && isa<NamedDecl>(TheDecl)) {
1136    std::string Name = cast<NamedDecl>(TheDecl)->getNameAsString();
1137    if (!Name.empty())
1138      OS << " '" << Name << '\'';
1139  }
1140
1141  OS << '\n';
1142}
1143
1144/// \brief Figure out if an expression could be turned into a call.
1145///
1146/// Use this when trying to recover from an error where the programmer may have
1147/// written just the name of a function instead of actually calling it.
1148///
1149/// \param E - The expression to examine.
1150/// \param ZeroArgCallReturnTy - If the expression can be turned into a call
1151///  with no arguments, this parameter is set to the type returned by such a
1152///  call; otherwise, it is set to an empty QualType.
1153/// \param OverloadSet - If the expression is an overloaded function
1154///  name, this parameter is populated with the decls of the various overloads.
1155bool Sema::tryExprAsCall(Expr &E, QualType &ZeroArgCallReturnTy,
1156                         UnresolvedSetImpl &OverloadSet) {
1157  ZeroArgCallReturnTy = QualType();
1158  OverloadSet.clear();
1159
1160  const OverloadExpr *Overloads = NULL;
1161  bool IsMemExpr = false;
1162  if (E.getType() == Context.OverloadTy) {
1163    OverloadExpr::FindResult FR = OverloadExpr::find(const_cast<Expr*>(&E));
1164
1165    // Ignore overloads that are pointer-to-member constants.
1166    if (FR.HasFormOfMemberPointer)
1167      return false;
1168
1169    Overloads = FR.Expression;
1170  } else if (E.getType() == Context.BoundMemberTy) {
1171    Overloads = dyn_cast<UnresolvedMemberExpr>(E.IgnoreParens());
1172    IsMemExpr = true;
1173  }
1174
1175  bool Ambiguous = false;
1176
1177  if (Overloads) {
1178    for (OverloadExpr::decls_iterator it = Overloads->decls_begin(),
1179         DeclsEnd = Overloads->decls_end(); it != DeclsEnd; ++it) {
1180      OverloadSet.addDecl(*it);
1181
1182      // Check whether the function is a non-template, non-member which takes no
1183      // arguments.
1184      if (IsMemExpr)
1185        continue;
1186      if (const FunctionDecl *OverloadDecl
1187            = dyn_cast<FunctionDecl>((*it)->getUnderlyingDecl())) {
1188        if (OverloadDecl->getMinRequiredArguments() == 0) {
1189          if (!ZeroArgCallReturnTy.isNull() && !Ambiguous) {
1190            ZeroArgCallReturnTy = QualType();
1191            Ambiguous = true;
1192          } else
1193            ZeroArgCallReturnTy = OverloadDecl->getResultType();
1194        }
1195      }
1196    }
1197
1198    // If it's not a member, use better machinery to try to resolve the call
1199    if (!IsMemExpr)
1200      return !ZeroArgCallReturnTy.isNull();
1201  }
1202
1203  // Attempt to call the member with no arguments - this will correctly handle
1204  // member templates with defaults/deduction of template arguments, overloads
1205  // with default arguments, etc.
1206  if (IsMemExpr && !E.isTypeDependent()) {
1207    bool Suppress = getDiagnostics().getSuppressAllDiagnostics();
1208    getDiagnostics().setSuppressAllDiagnostics(true);
1209    ExprResult R = BuildCallToMemberFunction(NULL, &E, SourceLocation(), None,
1210                                             SourceLocation());
1211    getDiagnostics().setSuppressAllDiagnostics(Suppress);
1212    if (R.isUsable()) {
1213      ZeroArgCallReturnTy = R.get()->getType();
1214      return true;
1215    }
1216    return false;
1217  }
1218
1219  if (const DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(E.IgnoreParens())) {
1220    if (const FunctionDecl *Fun = dyn_cast<FunctionDecl>(DeclRef->getDecl())) {
1221      if (Fun->getMinRequiredArguments() == 0)
1222        ZeroArgCallReturnTy = Fun->getResultType();
1223      return true;
1224    }
1225  }
1226
1227  // We don't have an expression that's convenient to get a FunctionDecl from,
1228  // but we can at least check if the type is "function of 0 arguments".
1229  QualType ExprTy = E.getType();
1230  const FunctionType *FunTy = NULL;
1231  QualType PointeeTy = ExprTy->getPointeeType();
1232  if (!PointeeTy.isNull())
1233    FunTy = PointeeTy->getAs<FunctionType>();
1234  if (!FunTy)
1235    FunTy = ExprTy->getAs<FunctionType>();
1236
1237  if (const FunctionProtoType *FPT =
1238      dyn_cast_or_null<FunctionProtoType>(FunTy)) {
1239    if (FPT->getNumArgs() == 0)
1240      ZeroArgCallReturnTy = FunTy->getResultType();
1241    return true;
1242  }
1243  return false;
1244}
1245
1246/// \brief Give notes for a set of overloads.
1247///
1248/// A companion to tryExprAsCall. In cases when the name that the programmer
1249/// wrote was an overloaded function, we may be able to make some guesses about
1250/// plausible overloads based on their return types; such guesses can be handed
1251/// off to this method to be emitted as notes.
1252///
1253/// \param Overloads - The overloads to note.
1254/// \param FinalNoteLoc - If we've suppressed printing some overloads due to
1255///  -fshow-overloads=best, this is the location to attach to the note about too
1256///  many candidates. Typically this will be the location of the original
1257///  ill-formed expression.
1258static void noteOverloads(Sema &S, const UnresolvedSetImpl &Overloads,
1259                          const SourceLocation FinalNoteLoc) {
1260  int ShownOverloads = 0;
1261  int SuppressedOverloads = 0;
1262  for (UnresolvedSetImpl::iterator It = Overloads.begin(),
1263       DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) {
1264    // FIXME: Magic number for max shown overloads stolen from
1265    // OverloadCandidateSet::NoteCandidates.
1266    if (ShownOverloads >= 4 && S.Diags.getShowOverloads() == Ovl_Best) {
1267      ++SuppressedOverloads;
1268      continue;
1269    }
1270
1271    NamedDecl *Fn = (*It)->getUnderlyingDecl();
1272    S.Diag(Fn->getLocation(), diag::note_possible_target_of_call);
1273    ++ShownOverloads;
1274  }
1275
1276  if (SuppressedOverloads)
1277    S.Diag(FinalNoteLoc, diag::note_ovl_too_many_candidates)
1278      << SuppressedOverloads;
1279}
1280
1281static void notePlausibleOverloads(Sema &S, SourceLocation Loc,
1282                                   const UnresolvedSetImpl &Overloads,
1283                                   bool (*IsPlausibleResult)(QualType)) {
1284  if (!IsPlausibleResult)
1285    return noteOverloads(S, Overloads, Loc);
1286
1287  UnresolvedSet<2> PlausibleOverloads;
1288  for (OverloadExpr::decls_iterator It = Overloads.begin(),
1289         DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) {
1290    const FunctionDecl *OverloadDecl = cast<FunctionDecl>(*It);
1291    QualType OverloadResultTy = OverloadDecl->getResultType();
1292    if (IsPlausibleResult(OverloadResultTy))
1293      PlausibleOverloads.addDecl(It.getDecl());
1294  }
1295  noteOverloads(S, PlausibleOverloads, Loc);
1296}
1297
1298/// Determine whether the given expression can be called by just
1299/// putting parentheses after it.  Notably, expressions with unary
1300/// operators can't be because the unary operator will start parsing
1301/// outside the call.
1302static bool IsCallableWithAppend(Expr *E) {
1303  E = E->IgnoreImplicit();
1304  return (!isa<CStyleCastExpr>(E) &&
1305          !isa<UnaryOperator>(E) &&
1306          !isa<BinaryOperator>(E) &&
1307          !isa<CXXOperatorCallExpr>(E));
1308}
1309
1310bool Sema::tryToRecoverWithCall(ExprResult &E, const PartialDiagnostic &PD,
1311                                bool ForceComplain,
1312                                bool (*IsPlausibleResult)(QualType)) {
1313  SourceLocation Loc = E.get()->getExprLoc();
1314  SourceRange Range = E.get()->getSourceRange();
1315
1316  QualType ZeroArgCallTy;
1317  UnresolvedSet<4> Overloads;
1318  if (tryExprAsCall(*E.get(), ZeroArgCallTy, Overloads) &&
1319      !ZeroArgCallTy.isNull() &&
1320      (!IsPlausibleResult || IsPlausibleResult(ZeroArgCallTy))) {
1321    // At this point, we know E is potentially callable with 0
1322    // arguments and that it returns something of a reasonable type,
1323    // so we can emit a fixit and carry on pretending that E was
1324    // actually a CallExpr.
1325    SourceLocation ParenInsertionLoc = PP.getLocForEndOfToken(Range.getEnd());
1326    Diag(Loc, PD)
1327      << /*zero-arg*/ 1 << Range
1328      << (IsCallableWithAppend(E.get())
1329          ? FixItHint::CreateInsertion(ParenInsertionLoc, "()")
1330          : FixItHint());
1331    notePlausibleOverloads(*this, Loc, Overloads, IsPlausibleResult);
1332
1333    // FIXME: Try this before emitting the fixit, and suppress diagnostics
1334    // while doing so.
1335    E = ActOnCallExpr(0, E.take(), Range.getEnd(), None,
1336                      Range.getEnd().getLocWithOffset(1));
1337    return true;
1338  }
1339
1340  if (!ForceComplain) return false;
1341
1342  Diag(Loc, PD) << /*not zero-arg*/ 0 << Range;
1343  notePlausibleOverloads(*this, Loc, Overloads, IsPlausibleResult);
1344  E = ExprError();
1345  return true;
1346}
1347
1348IdentifierInfo *Sema::getSuperIdentifier() const {
1349  if (!Ident_super)
1350    Ident_super = &Context.Idents.get("super");
1351  return Ident_super;
1352}
1353
1354IdentifierInfo *Sema::getFloat128Identifier() const {
1355  if (!Ident___float128)
1356    Ident___float128 = &Context.Idents.get("__float128");
1357  return Ident___float128;
1358}
1359
1360void Sema::PushCapturedRegionScope(Scope *S, CapturedDecl *CD, RecordDecl *RD,
1361                                   CapturedRegionKind K) {
1362  CapturingScopeInfo *CSI = new CapturedRegionScopeInfo(getDiagnostics(), S, CD, RD,
1363                                                        CD->getContextParam(), K);
1364  CSI->ReturnType = Context.VoidTy;
1365  FunctionScopes.push_back(CSI);
1366}
1367
1368CapturedRegionScopeInfo *Sema::getCurCapturedRegion() {
1369  if (FunctionScopes.empty())
1370    return 0;
1371
1372  return dyn_cast<CapturedRegionScopeInfo>(FunctionScopes.back());
1373}
1374