1//===--- Sema.cpp - AST Builder and Semantic Analysis Implementation ------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the actions class which performs semantic analysis and
11// builds an AST out of a parse stream.
12//
13//===----------------------------------------------------------------------===//
14
15#include "clang/Sema/SemaInternal.h"
16#include "clang/Sema/DelayedDiagnostic.h"
17#include "TargetAttributesSema.h"
18#include "llvm/ADT/DenseMap.h"
19#include "llvm/ADT/SmallSet.h"
20#include "llvm/ADT/APFloat.h"
21#include "clang/Sema/CXXFieldCollector.h"
22#include "clang/Sema/TemplateDeduction.h"
23#include "clang/Sema/ExternalSemaSource.h"
24#include "clang/Sema/ObjCMethodList.h"
25#include "clang/Sema/PrettyDeclStackTrace.h"
26#include "clang/Sema/Scope.h"
27#include "clang/Sema/ScopeInfo.h"
28#include "clang/Sema/SemaConsumer.h"
29#include "clang/AST/ASTContext.h"
30#include "clang/AST/ASTDiagnostic.h"
31#include "clang/AST/DeclCXX.h"
32#include "clang/AST/DeclObjC.h"
33#include "clang/AST/Expr.h"
34#include "clang/AST/ExprCXX.h"
35#include "clang/AST/StmtCXX.h"
36#include "clang/Lex/HeaderSearch.h"
37#include "clang/Lex/Preprocessor.h"
38#include "clang/Basic/FileManager.h"
39#include "clang/Basic/PartialDiagnostic.h"
40#include "clang/Basic/TargetInfo.h"
41using namespace clang;
42using namespace sema;
43
44FunctionScopeInfo::~FunctionScopeInfo() { }
45
46void FunctionScopeInfo::Clear() {
47  HasBranchProtectedScope = false;
48  HasBranchIntoScope = false;
49  HasIndirectGoto = false;
50
51  SwitchStack.clear();
52  Returns.clear();
53  ErrorTrap.reset();
54  PossiblyUnreachableDiags.clear();
55}
56
57BlockScopeInfo::~BlockScopeInfo() { }
58LambdaScopeInfo::~LambdaScopeInfo() { }
59
60PrintingPolicy Sema::getPrintingPolicy(const ASTContext &Context,
61                                       const Preprocessor &PP) {
62  PrintingPolicy Policy = Context.getPrintingPolicy();
63  Policy.Bool = Context.getLangOpts().Bool;
64  if (!Policy.Bool) {
65    if (MacroInfo *BoolMacro = PP.getMacroInfo(&Context.Idents.get("bool"))) {
66      Policy.Bool = BoolMacro->isObjectLike() &&
67        BoolMacro->getNumTokens() == 1 &&
68        BoolMacro->getReplacementToken(0).is(tok::kw__Bool);
69    }
70  }
71
72  return Policy;
73}
74
75void Sema::ActOnTranslationUnitScope(Scope *S) {
76  TUScope = S;
77  PushDeclContext(S, Context.getTranslationUnitDecl());
78
79  VAListTagName = PP.getIdentifierInfo("__va_list_tag");
80}
81
82Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
83           TranslationUnitKind TUKind,
84           CodeCompleteConsumer *CodeCompleter)
85  : TheTargetAttributesSema(0), FPFeatures(pp.getLangOpts()),
86    LangOpts(pp.getLangOpts()), PP(pp), Context(ctxt), Consumer(consumer),
87    Diags(PP.getDiagnostics()), SourceMgr(PP.getSourceManager()),
88    CollectStats(false), ExternalSource(0), CodeCompleter(CodeCompleter),
89    CurContext(0), OriginalLexicalContext(0),
90    PackContext(0), MSStructPragmaOn(false), VisContext(0),
91    ExprNeedsCleanups(false), LateTemplateParser(0), OpaqueParser(0),
92    IdResolver(pp), StdInitializerList(0), CXXTypeInfoDecl(0), MSVCGuidDecl(0),
93    NSNumberDecl(0), NSArrayDecl(0), ArrayWithObjectsMethod(0),
94    NSDictionaryDecl(0), DictionaryWithObjectsMethod(0),
95    GlobalNewDeleteDeclared(false),
96    ObjCShouldCallSuperDealloc(false),
97    ObjCShouldCallSuperFinalize(false),
98    TUKind(TUKind),
99    NumSFINAEErrors(0), InFunctionDeclarator(0), SuppressAccessChecking(false),
100    AccessCheckingSFINAE(false), InNonInstantiationSFINAEContext(false),
101    NonInstantiationEntries(0), ArgumentPackSubstitutionIndex(-1),
102    CurrentInstantiationScope(0), TyposCorrected(0),
103    AnalysisWarnings(*this)
104{
105  TUScope = 0;
106
107  LoadedExternalKnownNamespaces = false;
108  for (unsigned I = 0; I != NSAPI::NumNSNumberLiteralMethods; ++I)
109    NSNumberLiteralMethods[I] = 0;
110
111  if (getLangOpts().ObjC1)
112    NSAPIObj.reset(new NSAPI(Context));
113
114  if (getLangOpts().CPlusPlus)
115    FieldCollector.reset(new CXXFieldCollector());
116
117  // Tell diagnostics how to render things from the AST library.
118  PP.getDiagnostics().SetArgToStringFn(&FormatASTNodeDiagnosticArgument,
119                                       &Context);
120
121  ExprEvalContexts.push_back(
122        ExpressionEvaluationContextRecord(PotentiallyEvaluated, 0,
123                                          false, 0, false));
124
125  FunctionScopes.push_back(new FunctionScopeInfo(Diags));
126}
127
128void Sema::Initialize() {
129  // Tell the AST consumer about this Sema object.
130  Consumer.Initialize(Context);
131
132  // FIXME: Isn't this redundant with the initialization above?
133  if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
134    SC->InitializeSema(*this);
135
136  // Tell the external Sema source about this Sema object.
137  if (ExternalSemaSource *ExternalSema
138      = dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
139    ExternalSema->InitializeSema(*this);
140
141  // Initialize predefined 128-bit integer types, if needed.
142  if (PP.getTargetInfo().getPointerWidth(0) >= 64) {
143    // If either of the 128-bit integer types are unavailable to name lookup,
144    // define them now.
145    DeclarationName Int128 = &Context.Idents.get("__int128_t");
146    if (IdResolver.begin(Int128) == IdResolver.end())
147      PushOnScopeChains(Context.getInt128Decl(), TUScope);
148
149    DeclarationName UInt128 = &Context.Idents.get("__uint128_t");
150    if (IdResolver.begin(UInt128) == IdResolver.end())
151      PushOnScopeChains(Context.getUInt128Decl(), TUScope);
152  }
153
154
155  // Initialize predefined Objective-C types:
156  if (PP.getLangOpts().ObjC1) {
157    // If 'SEL' does not yet refer to any declarations, make it refer to the
158    // predefined 'SEL'.
159    DeclarationName SEL = &Context.Idents.get("SEL");
160    if (IdResolver.begin(SEL) == IdResolver.end())
161      PushOnScopeChains(Context.getObjCSelDecl(), TUScope);
162
163    // If 'id' does not yet refer to any declarations, make it refer to the
164    // predefined 'id'.
165    DeclarationName Id = &Context.Idents.get("id");
166    if (IdResolver.begin(Id) == IdResolver.end())
167      PushOnScopeChains(Context.getObjCIdDecl(), TUScope);
168
169    // Create the built-in typedef for 'Class'.
170    DeclarationName Class = &Context.Idents.get("Class");
171    if (IdResolver.begin(Class) == IdResolver.end())
172      PushOnScopeChains(Context.getObjCClassDecl(), TUScope);
173
174    // Create the built-in forward declaratino for 'Protocol'.
175    DeclarationName Protocol = &Context.Idents.get("Protocol");
176    if (IdResolver.begin(Protocol) == IdResolver.end())
177      PushOnScopeChains(Context.getObjCProtocolDecl(), TUScope);
178  }
179}
180
181Sema::~Sema() {
182  if (PackContext) FreePackedContext();
183  if (VisContext) FreeVisContext();
184  delete TheTargetAttributesSema;
185  MSStructPragmaOn = false;
186  // Kill all the active scopes.
187  for (unsigned I = 1, E = FunctionScopes.size(); I != E; ++I)
188    delete FunctionScopes[I];
189  if (FunctionScopes.size() == 1)
190    delete FunctionScopes[0];
191
192  // Tell the SemaConsumer to forget about us; we're going out of scope.
193  if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
194    SC->ForgetSema();
195
196  // Detach from the external Sema source.
197  if (ExternalSemaSource *ExternalSema
198        = dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
199    ExternalSema->ForgetSema();
200}
201
202
203/// makeUnavailableInSystemHeader - There is an error in the current
204/// context.  If we're still in a system header, and we can plausibly
205/// make the relevant declaration unavailable instead of erroring, do
206/// so and return true.
207bool Sema::makeUnavailableInSystemHeader(SourceLocation loc,
208                                         StringRef msg) {
209  // If we're not in a function, it's an error.
210  FunctionDecl *fn = dyn_cast<FunctionDecl>(CurContext);
211  if (!fn) return false;
212
213  // If we're in template instantiation, it's an error.
214  if (!ActiveTemplateInstantiations.empty())
215    return false;
216
217  // If that function's not in a system header, it's an error.
218  if (!Context.getSourceManager().isInSystemHeader(loc))
219    return false;
220
221  // If the function is already unavailable, it's not an error.
222  if (fn->hasAttr<UnavailableAttr>()) return true;
223
224  fn->addAttr(new (Context) UnavailableAttr(loc, Context, msg));
225  return true;
226}
227
228ASTMutationListener *Sema::getASTMutationListener() const {
229  return getASTConsumer().GetASTMutationListener();
230}
231
232/// \brief Print out statistics about the semantic analysis.
233void Sema::PrintStats() const {
234  llvm::errs() << "\n*** Semantic Analysis Stats:\n";
235  llvm::errs() << NumSFINAEErrors << " SFINAE diagnostics trapped.\n";
236
237  BumpAlloc.PrintStats();
238  AnalysisWarnings.PrintStats();
239}
240
241/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast.
242/// If there is already an implicit cast, merge into the existing one.
243/// The result is of the given category.
244ExprResult Sema::ImpCastExprToType(Expr *E, QualType Ty,
245                                   CastKind Kind, ExprValueKind VK,
246                                   const CXXCastPath *BasePath,
247                                   CheckedConversionKind CCK) {
248#ifndef NDEBUG
249  if (VK == VK_RValue && !E->isRValue()) {
250    switch (Kind) {
251    default:
252      assert(0 && "can't implicitly cast lvalue to rvalue with this cast kind");
253    case CK_LValueToRValue:
254    case CK_ArrayToPointerDecay:
255    case CK_FunctionToPointerDecay:
256    case CK_ToVoid:
257      break;
258    }
259  }
260  assert((VK == VK_RValue || !E->isRValue()) && "can't cast rvalue to lvalue");
261#endif
262
263  QualType ExprTy = Context.getCanonicalType(E->getType());
264  QualType TypeTy = Context.getCanonicalType(Ty);
265
266  if (ExprTy == TypeTy)
267    return Owned(E);
268
269  if (getLangOpts().ObjCAutoRefCount)
270    CheckObjCARCConversion(SourceRange(), Ty, E, CCK);
271
272  // If this is a derived-to-base cast to a through a virtual base, we
273  // need a vtable.
274  if (Kind == CK_DerivedToBase &&
275      BasePathInvolvesVirtualBase(*BasePath)) {
276    QualType T = E->getType();
277    if (const PointerType *Pointer = T->getAs<PointerType>())
278      T = Pointer->getPointeeType();
279    if (const RecordType *RecordTy = T->getAs<RecordType>())
280      MarkVTableUsed(E->getLocStart(),
281                     cast<CXXRecordDecl>(RecordTy->getDecl()));
282  }
283
284  if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(E)) {
285    if (ImpCast->getCastKind() == Kind && (!BasePath || BasePath->empty())) {
286      ImpCast->setType(Ty);
287      ImpCast->setValueKind(VK);
288      return Owned(E);
289    }
290  }
291
292  return Owned(ImplicitCastExpr::Create(Context, Ty, Kind, E, BasePath, VK));
293}
294
295/// ScalarTypeToBooleanCastKind - Returns the cast kind corresponding
296/// to the conversion from scalar type ScalarTy to the Boolean type.
297CastKind Sema::ScalarTypeToBooleanCastKind(QualType ScalarTy) {
298  switch (ScalarTy->getScalarTypeKind()) {
299  case Type::STK_Bool: return CK_NoOp;
300  case Type::STK_CPointer: return CK_PointerToBoolean;
301  case Type::STK_BlockPointer: return CK_PointerToBoolean;
302  case Type::STK_ObjCObjectPointer: return CK_PointerToBoolean;
303  case Type::STK_MemberPointer: return CK_MemberPointerToBoolean;
304  case Type::STK_Integral: return CK_IntegralToBoolean;
305  case Type::STK_Floating: return CK_FloatingToBoolean;
306  case Type::STK_IntegralComplex: return CK_IntegralComplexToBoolean;
307  case Type::STK_FloatingComplex: return CK_FloatingComplexToBoolean;
308  }
309  return CK_Invalid;
310}
311
312/// \brief Used to prune the decls of Sema's UnusedFileScopedDecls vector.
313static bool ShouldRemoveFromUnused(Sema *SemaRef, const DeclaratorDecl *D) {
314  if (D->isUsed())
315    return true;
316
317  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
318    // UnusedFileScopedDecls stores the first declaration.
319    // The declaration may have become definition so check again.
320    const FunctionDecl *DeclToCheck;
321    if (FD->hasBody(DeclToCheck))
322      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
323
324    // Later redecls may add new information resulting in not having to warn,
325    // so check again.
326    DeclToCheck = FD->getMostRecentDecl();
327    if (DeclToCheck != FD)
328      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
329  }
330
331  if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
332    // UnusedFileScopedDecls stores the first declaration.
333    // The declaration may have become definition so check again.
334    const VarDecl *DeclToCheck = VD->getDefinition();
335    if (DeclToCheck)
336      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
337
338    // Later redecls may add new information resulting in not having to warn,
339    // so check again.
340    DeclToCheck = VD->getMostRecentDecl();
341    if (DeclToCheck != VD)
342      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
343  }
344
345  return false;
346}
347
348namespace {
349  struct UndefinedInternal {
350    NamedDecl *decl;
351    FullSourceLoc useLoc;
352
353    UndefinedInternal(NamedDecl *decl, FullSourceLoc useLoc)
354      : decl(decl), useLoc(useLoc) {}
355  };
356
357  bool operator<(const UndefinedInternal &l, const UndefinedInternal &r) {
358    return l.useLoc.isBeforeInTranslationUnitThan(r.useLoc);
359  }
360}
361
362/// checkUndefinedInternals - Check for undefined objects with internal linkage.
363static void checkUndefinedInternals(Sema &S) {
364  if (S.UndefinedInternals.empty()) return;
365
366  // Collect all the still-undefined entities with internal linkage.
367  SmallVector<UndefinedInternal, 16> undefined;
368  for (llvm::DenseMap<NamedDecl*,SourceLocation>::iterator
369         i = S.UndefinedInternals.begin(), e = S.UndefinedInternals.end();
370       i != e; ++i) {
371    NamedDecl *decl = i->first;
372
373    // Ignore attributes that have become invalid.
374    if (decl->isInvalidDecl()) continue;
375
376    // __attribute__((weakref)) is basically a definition.
377    if (decl->hasAttr<WeakRefAttr>()) continue;
378
379    if (FunctionDecl *fn = dyn_cast<FunctionDecl>(decl)) {
380      if (fn->isPure() || fn->hasBody())
381        continue;
382    } else {
383      if (cast<VarDecl>(decl)->hasDefinition() != VarDecl::DeclarationOnly)
384        continue;
385    }
386
387    // We build a FullSourceLoc so that we can sort with array_pod_sort.
388    FullSourceLoc loc(i->second, S.Context.getSourceManager());
389    undefined.push_back(UndefinedInternal(decl, loc));
390  }
391
392  if (undefined.empty()) return;
393
394  // Sort (in order of use site) so that we're not (as) dependent on
395  // the iteration order through an llvm::DenseMap.
396  llvm::array_pod_sort(undefined.begin(), undefined.end());
397
398  for (SmallVectorImpl<UndefinedInternal>::iterator
399         i = undefined.begin(), e = undefined.end(); i != e; ++i) {
400    NamedDecl *decl = i->decl;
401    S.Diag(decl->getLocation(), diag::warn_undefined_internal)
402      << isa<VarDecl>(decl) << decl;
403    S.Diag(i->useLoc, diag::note_used_here);
404  }
405}
406
407void Sema::LoadExternalWeakUndeclaredIdentifiers() {
408  if (!ExternalSource)
409    return;
410
411  SmallVector<std::pair<IdentifierInfo *, WeakInfo>, 4> WeakIDs;
412  ExternalSource->ReadWeakUndeclaredIdentifiers(WeakIDs);
413  for (unsigned I = 0, N = WeakIDs.size(); I != N; ++I) {
414    llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator Pos
415      = WeakUndeclaredIdentifiers.find(WeakIDs[I].first);
416    if (Pos != WeakUndeclaredIdentifiers.end())
417      continue;
418
419    WeakUndeclaredIdentifiers.insert(WeakIDs[I]);
420  }
421}
422
423/// ActOnEndOfTranslationUnit - This is called at the very end of the
424/// translation unit when EOF is reached and all but the top-level scope is
425/// popped.
426void Sema::ActOnEndOfTranslationUnit() {
427  // Only complete translation units define vtables and perform implicit
428  // instantiations.
429  if (TUKind == TU_Complete) {
430    DiagnoseUseOfUnimplementedSelectors();
431
432    // If any dynamic classes have their key function defined within
433    // this translation unit, then those vtables are considered "used" and must
434    // be emitted.
435    for (DynamicClassesType::iterator I = DynamicClasses.begin(ExternalSource),
436                                      E = DynamicClasses.end();
437         I != E; ++I) {
438      assert(!(*I)->isDependentType() &&
439             "Should not see dependent types here!");
440      if (const CXXMethodDecl *KeyFunction = Context.getKeyFunction(*I)) {
441        const FunctionDecl *Definition = 0;
442        if (KeyFunction->hasBody(Definition))
443          MarkVTableUsed(Definition->getLocation(), *I, true);
444      }
445    }
446
447    // If DefinedUsedVTables ends up marking any virtual member functions it
448    // might lead to more pending template instantiations, which we then need
449    // to instantiate.
450    DefineUsedVTables();
451
452    // C++: Perform implicit template instantiations.
453    //
454    // FIXME: When we perform these implicit instantiations, we do not
455    // carefully keep track of the point of instantiation (C++ [temp.point]).
456    // This means that name lookup that occurs within the template
457    // instantiation will always happen at the end of the translation unit,
458    // so it will find some names that should not be found. Although this is
459    // common behavior for C++ compilers, it is technically wrong. In the
460    // future, we either need to be able to filter the results of name lookup
461    // or we need to perform template instantiations earlier.
462    PerformPendingInstantiations();
463  }
464
465  // Remove file scoped decls that turned out to be used.
466  UnusedFileScopedDecls.erase(std::remove_if(UnusedFileScopedDecls.begin(0,
467                                                                         true),
468                                             UnusedFileScopedDecls.end(),
469                              std::bind1st(std::ptr_fun(ShouldRemoveFromUnused),
470                                           this)),
471                              UnusedFileScopedDecls.end());
472
473  if (TUKind == TU_Prefix) {
474    // Translation unit prefixes don't need any of the checking below.
475    TUScope = 0;
476    return;
477  }
478
479  // Check for #pragma weak identifiers that were never declared
480  // FIXME: This will cause diagnostics to be emitted in a non-determinstic
481  // order!  Iterating over a densemap like this is bad.
482  LoadExternalWeakUndeclaredIdentifiers();
483  for (llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator
484       I = WeakUndeclaredIdentifiers.begin(),
485       E = WeakUndeclaredIdentifiers.end(); I != E; ++I) {
486    if (I->second.getUsed()) continue;
487
488    Diag(I->second.getLocation(), diag::warn_weak_identifier_undeclared)
489      << I->first;
490  }
491
492  if (TUKind == TU_Module) {
493    // If we are building a module, resolve all of the exported declarations
494    // now.
495    if (Module *CurrentModule = PP.getCurrentModule()) {
496      ModuleMap &ModMap = PP.getHeaderSearchInfo().getModuleMap();
497
498      llvm::SmallVector<Module *, 2> Stack;
499      Stack.push_back(CurrentModule);
500      while (!Stack.empty()) {
501        Module *Mod = Stack.back();
502        Stack.pop_back();
503
504        // Resolve the exported declarations.
505        // FIXME: Actually complain, once we figure out how to teach the
506        // diagnostic client to deal with complains in the module map at this
507        // point.
508        ModMap.resolveExports(Mod, /*Complain=*/false);
509
510        // Queue the submodules, so their exports will also be resolved.
511        for (Module::submodule_iterator Sub = Mod->submodule_begin(),
512                                     SubEnd = Mod->submodule_end();
513             Sub != SubEnd; ++Sub) {
514          Stack.push_back(*Sub);
515        }
516      }
517    }
518
519    // Modules don't need any of the checking below.
520    TUScope = 0;
521    return;
522  }
523
524  // C99 6.9.2p2:
525  //   A declaration of an identifier for an object that has file
526  //   scope without an initializer, and without a storage-class
527  //   specifier or with the storage-class specifier static,
528  //   constitutes a tentative definition. If a translation unit
529  //   contains one or more tentative definitions for an identifier,
530  //   and the translation unit contains no external definition for
531  //   that identifier, then the behavior is exactly as if the
532  //   translation unit contains a file scope declaration of that
533  //   identifier, with the composite type as of the end of the
534  //   translation unit, with an initializer equal to 0.
535  llvm::SmallSet<VarDecl *, 32> Seen;
536  for (TentativeDefinitionsType::iterator
537            T = TentativeDefinitions.begin(ExternalSource),
538         TEnd = TentativeDefinitions.end();
539       T != TEnd; ++T)
540  {
541    VarDecl *VD = (*T)->getActingDefinition();
542
543    // If the tentative definition was completed, getActingDefinition() returns
544    // null. If we've already seen this variable before, insert()'s second
545    // return value is false.
546    if (VD == 0 || VD->isInvalidDecl() || !Seen.insert(VD))
547      continue;
548
549    if (const IncompleteArrayType *ArrayT
550        = Context.getAsIncompleteArrayType(VD->getType())) {
551      if (RequireCompleteType(VD->getLocation(),
552                              ArrayT->getElementType(),
553                              diag::err_tentative_def_incomplete_type_arr)) {
554        VD->setInvalidDecl();
555        continue;
556      }
557
558      // Set the length of the array to 1 (C99 6.9.2p5).
559      Diag(VD->getLocation(), diag::warn_tentative_incomplete_array);
560      llvm::APInt One(Context.getTypeSize(Context.getSizeType()), true);
561      QualType T = Context.getConstantArrayType(ArrayT->getElementType(),
562                                                One, ArrayType::Normal, 0);
563      VD->setType(T);
564    } else if (RequireCompleteType(VD->getLocation(), VD->getType(),
565                                   diag::err_tentative_def_incomplete_type))
566      VD->setInvalidDecl();
567
568    // Notify the consumer that we've completed a tentative definition.
569    if (!VD->isInvalidDecl())
570      Consumer.CompleteTentativeDefinition(VD);
571
572  }
573
574  if (LangOpts.CPlusPlus0x &&
575      Diags.getDiagnosticLevel(diag::warn_delegating_ctor_cycle,
576                               SourceLocation())
577        != DiagnosticsEngine::Ignored)
578    CheckDelegatingCtorCycles();
579
580  // If there were errors, disable 'unused' warnings since they will mostly be
581  // noise.
582  if (!Diags.hasErrorOccurred()) {
583    // Output warning for unused file scoped decls.
584    for (UnusedFileScopedDeclsType::iterator
585           I = UnusedFileScopedDecls.begin(ExternalSource),
586           E = UnusedFileScopedDecls.end(); I != E; ++I) {
587      if (ShouldRemoveFromUnused(this, *I))
588        continue;
589
590      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) {
591        const FunctionDecl *DiagD;
592        if (!FD->hasBody(DiagD))
593          DiagD = FD;
594        if (DiagD->isDeleted())
595          continue; // Deleted functions are supposed to be unused.
596        if (DiagD->isReferenced()) {
597          if (isa<CXXMethodDecl>(DiagD))
598            Diag(DiagD->getLocation(), diag::warn_unneeded_member_function)
599                  << DiagD->getDeclName();
600          else
601            Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
602                  << /*function*/0 << DiagD->getDeclName();
603        } else {
604          Diag(DiagD->getLocation(),
605               isa<CXXMethodDecl>(DiagD) ? diag::warn_unused_member_function
606                                         : diag::warn_unused_function)
607                << DiagD->getDeclName();
608        }
609      } else {
610        const VarDecl *DiagD = cast<VarDecl>(*I)->getDefinition();
611        if (!DiagD)
612          DiagD = cast<VarDecl>(*I);
613        if (DiagD->isReferenced()) {
614          Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
615                << /*variable*/1 << DiagD->getDeclName();
616        } else {
617          Diag(DiagD->getLocation(), diag::warn_unused_variable)
618                << DiagD->getDeclName();
619        }
620      }
621    }
622
623    checkUndefinedInternals(*this);
624  }
625
626  // Check we've noticed that we're no longer parsing the initializer for every
627  // variable. If we miss cases, then at best we have a performance issue and
628  // at worst a rejects-valid bug.
629  assert(ParsingInitForAutoVars.empty() &&
630         "Didn't unmark var as having its initializer parsed");
631
632  TUScope = 0;
633}
634
635
636//===----------------------------------------------------------------------===//
637// Helper functions.
638//===----------------------------------------------------------------------===//
639
640DeclContext *Sema::getFunctionLevelDeclContext() {
641  DeclContext *DC = CurContext;
642
643  while (true) {
644    if (isa<BlockDecl>(DC) || isa<EnumDecl>(DC)) {
645      DC = DC->getParent();
646    } else if (isa<CXXMethodDecl>(DC) &&
647               cast<CXXMethodDecl>(DC)->getOverloadedOperator() == OO_Call &&
648               cast<CXXRecordDecl>(DC->getParent())->isLambda()) {
649      DC = DC->getParent()->getParent();
650    }
651    else break;
652  }
653
654  return DC;
655}
656
657/// getCurFunctionDecl - If inside of a function body, this returns a pointer
658/// to the function decl for the function being parsed.  If we're currently
659/// in a 'block', this returns the containing context.
660FunctionDecl *Sema::getCurFunctionDecl() {
661  DeclContext *DC = getFunctionLevelDeclContext();
662  return dyn_cast<FunctionDecl>(DC);
663}
664
665ObjCMethodDecl *Sema::getCurMethodDecl() {
666  DeclContext *DC = getFunctionLevelDeclContext();
667  return dyn_cast<ObjCMethodDecl>(DC);
668}
669
670NamedDecl *Sema::getCurFunctionOrMethodDecl() {
671  DeclContext *DC = getFunctionLevelDeclContext();
672  if (isa<ObjCMethodDecl>(DC) || isa<FunctionDecl>(DC))
673    return cast<NamedDecl>(DC);
674  return 0;
675}
676
677void Sema::EmitCurrentDiagnostic(unsigned DiagID) {
678  // FIXME: It doesn't make sense to me that DiagID is an incoming argument here
679  // and yet we also use the current diag ID on the DiagnosticsEngine. This has
680  // been made more painfully obvious by the refactor that introduced this
681  // function, but it is possible that the incoming argument can be
682  // eliminnated. If it truly cannot be (for example, there is some reentrancy
683  // issue I am not seeing yet), then there should at least be a clarifying
684  // comment somewhere.
685  if (llvm::Optional<TemplateDeductionInfo*> Info = isSFINAEContext()) {
686    switch (DiagnosticIDs::getDiagnosticSFINAEResponse(
687              Diags.getCurrentDiagID())) {
688    case DiagnosticIDs::SFINAE_Report:
689      // We'll report the diagnostic below.
690      break;
691
692    case DiagnosticIDs::SFINAE_SubstitutionFailure:
693      // Count this failure so that we know that template argument deduction
694      // has failed.
695      ++NumSFINAEErrors;
696      Diags.setLastDiagnosticIgnored();
697      Diags.Clear();
698      return;
699
700    case DiagnosticIDs::SFINAE_AccessControl: {
701      // Per C++ Core Issue 1170, access control is part of SFINAE.
702      // Additionally, the AccessCheckingSFINAE flag can be used to temporarily
703      // make access control a part of SFINAE for the purposes of checking
704      // type traits.
705      if (!AccessCheckingSFINAE && !getLangOpts().CPlusPlus0x)
706        break;
707
708      SourceLocation Loc = Diags.getCurrentDiagLoc();
709
710      // Suppress this diagnostic.
711      ++NumSFINAEErrors;
712      Diags.setLastDiagnosticIgnored();
713      Diags.Clear();
714
715      // Now the diagnostic state is clear, produce a C++98 compatibility
716      // warning.
717      Diag(Loc, diag::warn_cxx98_compat_sfinae_access_control);
718
719      // The last diagnostic which Sema produced was ignored. Suppress any
720      // notes attached to it.
721      Diags.setLastDiagnosticIgnored();
722      return;
723    }
724
725    case DiagnosticIDs::SFINAE_Suppress:
726      // Make a copy of this suppressed diagnostic and store it with the
727      // template-deduction information;
728      Diagnostic DiagInfo(&Diags);
729
730      if (*Info)
731        (*Info)->addSuppressedDiagnostic(DiagInfo.getLocation(),
732                        PartialDiagnostic(DiagInfo,Context.getDiagAllocator()));
733
734      // Suppress this diagnostic.
735      Diags.setLastDiagnosticIgnored();
736      Diags.Clear();
737      return;
738    }
739  }
740
741  // Set up the context's printing policy based on our current state.
742  Context.setPrintingPolicy(getPrintingPolicy());
743
744  // Emit the diagnostic.
745  if (!Diags.EmitCurrentDiagnostic())
746    return;
747
748  // If this is not a note, and we're in a template instantiation
749  // that is different from the last template instantiation where
750  // we emitted an error, print a template instantiation
751  // backtrace.
752  if (!DiagnosticIDs::isBuiltinNote(DiagID) &&
753      !ActiveTemplateInstantiations.empty() &&
754      ActiveTemplateInstantiations.back()
755        != LastTemplateInstantiationErrorContext) {
756    PrintInstantiationStack();
757    LastTemplateInstantiationErrorContext = ActiveTemplateInstantiations.back();
758  }
759}
760
761Sema::SemaDiagnosticBuilder
762Sema::Diag(SourceLocation Loc, const PartialDiagnostic& PD) {
763  SemaDiagnosticBuilder Builder(Diag(Loc, PD.getDiagID()));
764  PD.Emit(Builder);
765
766  return Builder;
767}
768
769/// \brief Looks through the macro-expansion chain for the given
770/// location, looking for a macro expansion with the given name.
771/// If one is found, returns true and sets the location to that
772/// expansion loc.
773bool Sema::findMacroSpelling(SourceLocation &locref, StringRef name) {
774  SourceLocation loc = locref;
775  if (!loc.isMacroID()) return false;
776
777  // There's no good way right now to look at the intermediate
778  // expansions, so just jump to the expansion location.
779  loc = getSourceManager().getExpansionLoc(loc);
780
781  // If that's written with the name, stop here.
782  SmallVector<char, 16> buffer;
783  if (getPreprocessor().getSpelling(loc, buffer) == name) {
784    locref = loc;
785    return true;
786  }
787  return false;
788}
789
790/// \brief Determines the active Scope associated with the given declaration
791/// context.
792///
793/// This routine maps a declaration context to the active Scope object that
794/// represents that declaration context in the parser. It is typically used
795/// from "scope-less" code (e.g., template instantiation, lazy creation of
796/// declarations) that injects a name for name-lookup purposes and, therefore,
797/// must update the Scope.
798///
799/// \returns The scope corresponding to the given declaraion context, or NULL
800/// if no such scope is open.
801Scope *Sema::getScopeForContext(DeclContext *Ctx) {
802
803  if (!Ctx)
804    return 0;
805
806  Ctx = Ctx->getPrimaryContext();
807  for (Scope *S = getCurScope(); S; S = S->getParent()) {
808    // Ignore scopes that cannot have declarations. This is important for
809    // out-of-line definitions of static class members.
810    if (S->getFlags() & (Scope::DeclScope | Scope::TemplateParamScope))
811      if (DeclContext *Entity = static_cast<DeclContext *> (S->getEntity()))
812        if (Ctx == Entity->getPrimaryContext())
813          return S;
814  }
815
816  return 0;
817}
818
819/// \brief Enter a new function scope
820void Sema::PushFunctionScope() {
821  if (FunctionScopes.size() == 1) {
822    // Use the "top" function scope rather than having to allocate
823    // memory for a new scope.
824    FunctionScopes.back()->Clear();
825    FunctionScopes.push_back(FunctionScopes.back());
826    return;
827  }
828
829  FunctionScopes.push_back(new FunctionScopeInfo(getDiagnostics()));
830}
831
832void Sema::PushBlockScope(Scope *BlockScope, BlockDecl *Block) {
833  FunctionScopes.push_back(new BlockScopeInfo(getDiagnostics(),
834                                              BlockScope, Block));
835}
836
837void Sema::PushLambdaScope(CXXRecordDecl *Lambda,
838                           CXXMethodDecl *CallOperator) {
839  FunctionScopes.push_back(new LambdaScopeInfo(getDiagnostics(), Lambda,
840                                               CallOperator));
841}
842
843void Sema::PopFunctionScopeInfo(const AnalysisBasedWarnings::Policy *WP,
844                                const Decl *D, const BlockExpr *blkExpr) {
845  FunctionScopeInfo *Scope = FunctionScopes.pop_back_val();
846  assert(!FunctionScopes.empty() && "mismatched push/pop!");
847
848  // Issue any analysis-based warnings.
849  if (WP && D)
850    AnalysisWarnings.IssueWarnings(*WP, Scope, D, blkExpr);
851  else {
852    for (SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator
853         i = Scope->PossiblyUnreachableDiags.begin(),
854         e = Scope->PossiblyUnreachableDiags.end();
855         i != e; ++i) {
856      const sema::PossiblyUnreachableDiag &D = *i;
857      Diag(D.Loc, D.PD);
858    }
859  }
860
861  if (FunctionScopes.back() != Scope) {
862    delete Scope;
863  }
864}
865
866void Sema::PushCompoundScope() {
867  getCurFunction()->CompoundScopes.push_back(CompoundScopeInfo());
868}
869
870void Sema::PopCompoundScope() {
871  FunctionScopeInfo *CurFunction = getCurFunction();
872  assert(!CurFunction->CompoundScopes.empty() && "mismatched push/pop");
873
874  CurFunction->CompoundScopes.pop_back();
875}
876
877/// \brief Determine whether any errors occurred within this function/method/
878/// block.
879bool Sema::hasAnyUnrecoverableErrorsInThisFunction() const {
880  return getCurFunction()->ErrorTrap.hasUnrecoverableErrorOccurred();
881}
882
883BlockScopeInfo *Sema::getCurBlock() {
884  if (FunctionScopes.empty())
885    return 0;
886
887  return dyn_cast<BlockScopeInfo>(FunctionScopes.back());
888}
889
890LambdaScopeInfo *Sema::getCurLambda() {
891  if (FunctionScopes.empty())
892    return 0;
893
894  return dyn_cast<LambdaScopeInfo>(FunctionScopes.back());
895}
896
897// Pin this vtable to this file.
898ExternalSemaSource::~ExternalSemaSource() {}
899
900void ExternalSemaSource::ReadMethodPool(Selector Sel) { }
901
902void ExternalSemaSource::ReadKnownNamespaces(
903                           SmallVectorImpl<NamespaceDecl *> &Namespaces) {
904}
905
906void PrettyDeclStackTraceEntry::print(raw_ostream &OS) const {
907  SourceLocation Loc = this->Loc;
908  if (!Loc.isValid() && TheDecl) Loc = TheDecl->getLocation();
909  if (Loc.isValid()) {
910    Loc.print(OS, S.getSourceManager());
911    OS << ": ";
912  }
913  OS << Message;
914
915  if (TheDecl && isa<NamedDecl>(TheDecl)) {
916    std::string Name = cast<NamedDecl>(TheDecl)->getNameAsString();
917    if (!Name.empty())
918      OS << " '" << Name << '\'';
919  }
920
921  OS << '\n';
922}
923
924/// \brief Figure out if an expression could be turned into a call.
925///
926/// Use this when trying to recover from an error where the programmer may have
927/// written just the name of a function instead of actually calling it.
928///
929/// \param E - The expression to examine.
930/// \param ZeroArgCallReturnTy - If the expression can be turned into a call
931///  with no arguments, this parameter is set to the type returned by such a
932///  call; otherwise, it is set to an empty QualType.
933/// \param OverloadSet - If the expression is an overloaded function
934///  name, this parameter is populated with the decls of the various overloads.
935bool Sema::isExprCallable(const Expr &E, QualType &ZeroArgCallReturnTy,
936                          UnresolvedSetImpl &OverloadSet) {
937  ZeroArgCallReturnTy = QualType();
938  OverloadSet.clear();
939
940  if (E.getType() == Context.OverloadTy) {
941    OverloadExpr::FindResult FR = OverloadExpr::find(const_cast<Expr*>(&E));
942    const OverloadExpr *Overloads = FR.Expression;
943
944    for (OverloadExpr::decls_iterator it = Overloads->decls_begin(),
945         DeclsEnd = Overloads->decls_end(); it != DeclsEnd; ++it) {
946      OverloadSet.addDecl(*it);
947
948      // Check whether the function is a non-template which takes no
949      // arguments.
950      if (const FunctionDecl *OverloadDecl
951            = dyn_cast<FunctionDecl>((*it)->getUnderlyingDecl())) {
952        if (OverloadDecl->getMinRequiredArguments() == 0)
953          ZeroArgCallReturnTy = OverloadDecl->getResultType();
954      }
955    }
956
957    // Ignore overloads that are pointer-to-member constants.
958    if (FR.HasFormOfMemberPointer)
959      return false;
960
961    return true;
962  }
963
964  if (const DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(E.IgnoreParens())) {
965    if (const FunctionDecl *Fun = dyn_cast<FunctionDecl>(DeclRef->getDecl())) {
966      if (Fun->getMinRequiredArguments() == 0)
967        ZeroArgCallReturnTy = Fun->getResultType();
968      return true;
969    }
970  }
971
972  // We don't have an expression that's convenient to get a FunctionDecl from,
973  // but we can at least check if the type is "function of 0 arguments".
974  QualType ExprTy = E.getType();
975  const FunctionType *FunTy = NULL;
976  QualType PointeeTy = ExprTy->getPointeeType();
977  if (!PointeeTy.isNull())
978    FunTy = PointeeTy->getAs<FunctionType>();
979  if (!FunTy)
980    FunTy = ExprTy->getAs<FunctionType>();
981  if (!FunTy && ExprTy == Context.BoundMemberTy) {
982    // Look for the bound-member type.  If it's still overloaded, give up,
983    // although we probably should have fallen into the OverloadExpr case above
984    // if we actually have an overloaded bound member.
985    QualType BoundMemberTy = Expr::findBoundMemberType(&E);
986    if (!BoundMemberTy.isNull())
987      FunTy = BoundMemberTy->castAs<FunctionType>();
988  }
989
990  if (const FunctionProtoType *FPT =
991      dyn_cast_or_null<FunctionProtoType>(FunTy)) {
992    if (FPT->getNumArgs() == 0)
993      ZeroArgCallReturnTy = FunTy->getResultType();
994    return true;
995  }
996  return false;
997}
998
999/// \brief Give notes for a set of overloads.
1000///
1001/// A companion to isExprCallable. In cases when the name that the programmer
1002/// wrote was an overloaded function, we may be able to make some guesses about
1003/// plausible overloads based on their return types; such guesses can be handed
1004/// off to this method to be emitted as notes.
1005///
1006/// \param Overloads - The overloads to note.
1007/// \param FinalNoteLoc - If we've suppressed printing some overloads due to
1008///  -fshow-overloads=best, this is the location to attach to the note about too
1009///  many candidates. Typically this will be the location of the original
1010///  ill-formed expression.
1011static void noteOverloads(Sema &S, const UnresolvedSetImpl &Overloads,
1012                          const SourceLocation FinalNoteLoc) {
1013  int ShownOverloads = 0;
1014  int SuppressedOverloads = 0;
1015  for (UnresolvedSetImpl::iterator It = Overloads.begin(),
1016       DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) {
1017    // FIXME: Magic number for max shown overloads stolen from
1018    // OverloadCandidateSet::NoteCandidates.
1019    if (ShownOverloads >= 4 &&
1020        S.Diags.getShowOverloads() == DiagnosticsEngine::Ovl_Best) {
1021      ++SuppressedOverloads;
1022      continue;
1023    }
1024
1025    NamedDecl *Fn = (*It)->getUnderlyingDecl();
1026    S.Diag(Fn->getLocation(), diag::note_possible_target_of_call);
1027    ++ShownOverloads;
1028  }
1029
1030  if (SuppressedOverloads)
1031    S.Diag(FinalNoteLoc, diag::note_ovl_too_many_candidates)
1032      << SuppressedOverloads;
1033}
1034
1035static void notePlausibleOverloads(Sema &S, SourceLocation Loc,
1036                                   const UnresolvedSetImpl &Overloads,
1037                                   bool (*IsPlausibleResult)(QualType)) {
1038  if (!IsPlausibleResult)
1039    return noteOverloads(S, Overloads, Loc);
1040
1041  UnresolvedSet<2> PlausibleOverloads;
1042  for (OverloadExpr::decls_iterator It = Overloads.begin(),
1043         DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) {
1044    const FunctionDecl *OverloadDecl = cast<FunctionDecl>(*It);
1045    QualType OverloadResultTy = OverloadDecl->getResultType();
1046    if (IsPlausibleResult(OverloadResultTy))
1047      PlausibleOverloads.addDecl(It.getDecl());
1048  }
1049  noteOverloads(S, PlausibleOverloads, Loc);
1050}
1051
1052/// Determine whether the given expression can be called by just
1053/// putting parentheses after it.  Notably, expressions with unary
1054/// operators can't be because the unary operator will start parsing
1055/// outside the call.
1056static bool IsCallableWithAppend(Expr *E) {
1057  E = E->IgnoreImplicit();
1058  return (!isa<CStyleCastExpr>(E) &&
1059          !isa<UnaryOperator>(E) &&
1060          !isa<BinaryOperator>(E) &&
1061          !isa<CXXOperatorCallExpr>(E));
1062}
1063
1064bool Sema::tryToRecoverWithCall(ExprResult &E, const PartialDiagnostic &PD,
1065                                bool ForceComplain,
1066                                bool (*IsPlausibleResult)(QualType)) {
1067  SourceLocation Loc = E.get()->getExprLoc();
1068  SourceRange Range = E.get()->getSourceRange();
1069
1070  QualType ZeroArgCallTy;
1071  UnresolvedSet<4> Overloads;
1072  if (isExprCallable(*E.get(), ZeroArgCallTy, Overloads) &&
1073      !ZeroArgCallTy.isNull() &&
1074      (!IsPlausibleResult || IsPlausibleResult(ZeroArgCallTy))) {
1075    // At this point, we know E is potentially callable with 0
1076    // arguments and that it returns something of a reasonable type,
1077    // so we can emit a fixit and carry on pretending that E was
1078    // actually a CallExpr.
1079    SourceLocation ParenInsertionLoc =
1080      PP.getLocForEndOfToken(Range.getEnd());
1081    Diag(Loc, PD)
1082      << /*zero-arg*/ 1 << Range
1083      << (IsCallableWithAppend(E.get())
1084          ? FixItHint::CreateInsertion(ParenInsertionLoc, "()")
1085          : FixItHint());
1086    notePlausibleOverloads(*this, Loc, Overloads, IsPlausibleResult);
1087
1088    // FIXME: Try this before emitting the fixit, and suppress diagnostics
1089    // while doing so.
1090    E = ActOnCallExpr(0, E.take(), ParenInsertionLoc,
1091                      MultiExprArg(*this, 0, 0),
1092                      ParenInsertionLoc.getLocWithOffset(1));
1093    return true;
1094  }
1095
1096  if (!ForceComplain) return false;
1097
1098  Diag(Loc, PD) << /*not zero-arg*/ 0 << Range;
1099  notePlausibleOverloads(*this, Loc, Overloads, IsPlausibleResult);
1100  E = ExprError();
1101  return true;
1102}
1103