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/AST/ASTContext.h"
17#include "clang/AST/ASTDiagnostic.h"
18#include "clang/AST/DeclCXX.h"
19#include "clang/AST/DeclFriend.h"
20#include "clang/AST/DeclObjC.h"
21#include "clang/AST/Expr.h"
22#include "clang/AST/ExprCXX.h"
23#include "clang/AST/StmtCXX.h"
24#include "clang/Basic/DiagnosticOptions.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"
43using namespace clang;
44using namespace sema;
45
46SourceLocation Sema::getLocForEndOfToken(SourceLocation Loc, unsigned Offset) {
47  return Lexer::getLocForEndOfToken(Loc, Offset, SourceMgr, LangOpts);
48}
49
50ModuleLoader &Sema::getModuleLoader() const { return PP.getModuleLoader(); }
51
52PrintingPolicy Sema::getPrintingPolicy(const ASTContext &Context,
53                                       const Preprocessor &PP) {
54  PrintingPolicy Policy = Context.getPrintingPolicy();
55  // Our printing policy is copied over the ASTContext printing policy whenever
56  // a diagnostic is emitted, so recompute it.
57  Policy.Bool = Context.getLangOpts().Bool;
58  if (!Policy.Bool) {
59    if (const MacroInfo *BoolMacro = PP.getMacroInfo(Context.getBoolName())) {
60      Policy.Bool = BoolMacro->isObjectLike() &&
61                    BoolMacro->getNumTokens() == 1 &&
62                    BoolMacro->getReplacementToken(0).is(tok::kw__Bool);
63    }
64  }
65
66  return Policy;
67}
68
69void Sema::ActOnTranslationUnitScope(Scope *S) {
70  TUScope = S;
71  PushDeclContext(S, Context.getTranslationUnitDecl());
72}
73
74Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
75           TranslationUnitKind TUKind,
76           CodeCompleteConsumer *CodeCompleter)
77  : ExternalSource(nullptr),
78    isMultiplexExternalSource(false), FPFeatures(pp.getLangOpts()),
79    LangOpts(pp.getLangOpts()), PP(pp), Context(ctxt), Consumer(consumer),
80    Diags(PP.getDiagnostics()), SourceMgr(PP.getSourceManager()),
81    CollectStats(false), CodeCompleter(CodeCompleter),
82    CurContext(nullptr), OriginalLexicalContext(nullptr),
83    MSStructPragmaOn(false),
84    MSPointerToMemberRepresentationMethod(
85        LangOpts.getMSPointerToMemberRepresentationMethod()),
86    VtorDispStack(MSVtorDispAttr::Mode(LangOpts.VtorDispMode)),
87    PackStack(0), DataSegStack(nullptr), BSSSegStack(nullptr),
88    ConstSegStack(nullptr), CodeSegStack(nullptr), CurInitSeg(nullptr),
89    VisContext(nullptr),
90    IsBuildingRecoveryCallExpr(false),
91    Cleanup{}, LateTemplateParser(nullptr),
92    LateTemplateParserCleanup(nullptr),
93    OpaqueParser(nullptr), IdResolver(pp), StdInitializerList(nullptr),
94    CXXTypeInfoDecl(nullptr), MSVCGuidDecl(nullptr),
95    NSNumberDecl(nullptr), NSValueDecl(nullptr),
96    NSStringDecl(nullptr), StringWithUTF8StringMethod(nullptr),
97    ValueWithBytesObjCTypeMethod(nullptr),
98    NSArrayDecl(nullptr), ArrayWithObjectsMethod(nullptr),
99    NSDictionaryDecl(nullptr), DictionaryWithObjectsMethod(nullptr),
100    MSAsmLabelNameCounter(0),
101    GlobalNewDeleteDeclared(false),
102    TUKind(TUKind),
103    NumSFINAEErrors(0),
104    CachedFakeTopLevelModule(nullptr),
105    AccessCheckingSFINAE(false), InNonInstantiationSFINAEContext(false),
106    NonInstantiationEntries(0), ArgumentPackSubstitutionIndex(-1),
107    CurrentInstantiationScope(nullptr), DisableTypoCorrection(false),
108    TyposCorrected(0), AnalysisWarnings(*this), ThreadSafetyDeclCache(nullptr),
109    VarDataSharingAttributesStack(nullptr), CurScope(nullptr),
110    Ident_super(nullptr), Ident___float128(nullptr)
111{
112  TUScope = nullptr;
113
114  LoadedExternalKnownNamespaces = false;
115  for (unsigned I = 0; I != NSAPI::NumNSNumberLiteralMethods; ++I)
116    NSNumberLiteralMethods[I] = nullptr;
117
118  if (getLangOpts().ObjC1)
119    NSAPIObj.reset(new NSAPI(Context));
120
121  if (getLangOpts().CPlusPlus)
122    FieldCollector.reset(new CXXFieldCollector());
123
124  // Tell diagnostics how to render things from the AST library.
125  Diags.SetArgToStringFn(&FormatASTNodeDiagnosticArgument, &Context);
126
127  ExprEvalContexts.emplace_back(PotentiallyEvaluated, 0, CleanupInfo{}, nullptr,
128                                false);
129
130  FunctionScopes.push_back(new FunctionScopeInfo(Diags));
131
132  // Initilization of data sharing attributes stack for OpenMP
133  InitDataSharingAttributesStack();
134}
135
136void Sema::addImplicitTypedef(StringRef Name, QualType T) {
137  DeclarationName DN = &Context.Idents.get(Name);
138  if (IdResolver.begin(DN) == IdResolver.end())
139    PushOnScopeChains(Context.buildImplicitTypedef(T, Name), TUScope);
140}
141
142void Sema::Initialize() {
143  if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
144    SC->InitializeSema(*this);
145
146  // Tell the external Sema source about this Sema object.
147  if (ExternalSemaSource *ExternalSema
148      = dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
149    ExternalSema->InitializeSema(*this);
150
151  // This needs to happen after ExternalSemaSource::InitializeSema(this) or we
152  // will not be able to merge any duplicate __va_list_tag decls correctly.
153  VAListTagName = PP.getIdentifierInfo("__va_list_tag");
154
155  if (!TUScope)
156    return;
157
158  // Initialize predefined 128-bit integer types, if needed.
159  if (Context.getTargetInfo().hasInt128Type()) {
160    // If either of the 128-bit integer types are unavailable to name lookup,
161    // define them now.
162    DeclarationName Int128 = &Context.Idents.get("__int128_t");
163    if (IdResolver.begin(Int128) == IdResolver.end())
164      PushOnScopeChains(Context.getInt128Decl(), TUScope);
165
166    DeclarationName UInt128 = &Context.Idents.get("__uint128_t");
167    if (IdResolver.begin(UInt128) == IdResolver.end())
168      PushOnScopeChains(Context.getUInt128Decl(), TUScope);
169  }
170
171
172  // Initialize predefined Objective-C types:
173  if (getLangOpts().ObjC1) {
174    // If 'SEL' does not yet refer to any declarations, make it refer to the
175    // predefined 'SEL'.
176    DeclarationName SEL = &Context.Idents.get("SEL");
177    if (IdResolver.begin(SEL) == IdResolver.end())
178      PushOnScopeChains(Context.getObjCSelDecl(), TUScope);
179
180    // If 'id' does not yet refer to any declarations, make it refer to the
181    // predefined 'id'.
182    DeclarationName Id = &Context.Idents.get("id");
183    if (IdResolver.begin(Id) == IdResolver.end())
184      PushOnScopeChains(Context.getObjCIdDecl(), TUScope);
185
186    // Create the built-in typedef for 'Class'.
187    DeclarationName Class = &Context.Idents.get("Class");
188    if (IdResolver.begin(Class) == IdResolver.end())
189      PushOnScopeChains(Context.getObjCClassDecl(), TUScope);
190
191    // Create the built-in forward declaratino for 'Protocol'.
192    DeclarationName Protocol = &Context.Idents.get("Protocol");
193    if (IdResolver.begin(Protocol) == IdResolver.end())
194      PushOnScopeChains(Context.getObjCProtocolDecl(), TUScope);
195  }
196
197  // Create the internal type for the *StringMakeConstantString builtins.
198  DeclarationName ConstantString = &Context.Idents.get("__NSConstantString");
199  if (IdResolver.begin(ConstantString) == IdResolver.end())
200    PushOnScopeChains(Context.getCFConstantStringDecl(), TUScope);
201
202  // Initialize Microsoft "predefined C++ types".
203  if (getLangOpts().MSVCCompat) {
204    if (getLangOpts().CPlusPlus &&
205        IdResolver.begin(&Context.Idents.get("type_info")) == IdResolver.end())
206      PushOnScopeChains(Context.buildImplicitRecord("type_info", TTK_Class),
207                        TUScope);
208
209    addImplicitTypedef("size_t", Context.getSizeType());
210  }
211
212  // Initialize predefined OpenCL types and supported optional core features.
213  if (getLangOpts().OpenCL) {
214#define OPENCLEXT(Ext) \
215     if (Context.getTargetInfo().getSupportedOpenCLOpts().is_##Ext##_supported_core( \
216         getLangOpts().OpenCLVersion)) \
217       getOpenCLOptions().Ext = 1;
218#include "clang/Basic/OpenCLExtensions.def"
219
220    addImplicitTypedef("sampler_t", Context.OCLSamplerTy);
221    addImplicitTypedef("event_t", Context.OCLEventTy);
222    if (getLangOpts().OpenCLVersion >= 200) {
223      addImplicitTypedef("clk_event_t", Context.OCLClkEventTy);
224      addImplicitTypedef("queue_t", Context.OCLQueueTy);
225      addImplicitTypedef("ndrange_t", Context.OCLNDRangeTy);
226      addImplicitTypedef("reserve_id_t", Context.OCLReserveIDTy);
227      addImplicitTypedef("atomic_int", Context.getAtomicType(Context.IntTy));
228      addImplicitTypedef("atomic_uint",
229                         Context.getAtomicType(Context.UnsignedIntTy));
230      addImplicitTypedef("atomic_long", Context.getAtomicType(Context.LongTy));
231      addImplicitTypedef("atomic_ulong",
232                         Context.getAtomicType(Context.UnsignedLongTy));
233      addImplicitTypedef("atomic_float",
234                         Context.getAtomicType(Context.FloatTy));
235      addImplicitTypedef("atomic_double",
236                         Context.getAtomicType(Context.DoubleTy));
237      // OpenCLC v2.0, s6.13.11.6 requires that atomic_flag is implemented as
238      // 32-bit integer and OpenCLC v2.0, s6.1.1 int is always 32-bit wide.
239      addImplicitTypedef("atomic_flag", Context.getAtomicType(Context.IntTy));
240      addImplicitTypedef("atomic_intptr_t",
241                         Context.getAtomicType(Context.getIntPtrType()));
242      addImplicitTypedef("atomic_uintptr_t",
243                         Context.getAtomicType(Context.getUIntPtrType()));
244      addImplicitTypedef("atomic_size_t",
245                         Context.getAtomicType(Context.getSizeType()));
246      addImplicitTypedef("atomic_ptrdiff_t",
247                         Context.getAtomicType(Context.getPointerDiffType()));
248    }
249  }
250
251  if (Context.getTargetInfo().hasBuiltinMSVaList()) {
252    DeclarationName MSVaList = &Context.Idents.get("__builtin_ms_va_list");
253    if (IdResolver.begin(MSVaList) == IdResolver.end())
254      PushOnScopeChains(Context.getBuiltinMSVaListDecl(), TUScope);
255  }
256
257  DeclarationName BuiltinVaList = &Context.Idents.get("__builtin_va_list");
258  if (IdResolver.begin(BuiltinVaList) == IdResolver.end())
259    PushOnScopeChains(Context.getBuiltinVaListDecl(), TUScope);
260}
261
262Sema::~Sema() {
263  llvm::DeleteContainerSeconds(LateParsedTemplateMap);
264  if (VisContext) FreeVisContext();
265  // Kill all the active scopes.
266  for (unsigned I = 1, E = FunctionScopes.size(); I != E; ++I)
267    delete FunctionScopes[I];
268  if (FunctionScopes.size() == 1)
269    delete FunctionScopes[0];
270
271  // Tell the SemaConsumer to forget about us; we're going out of scope.
272  if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
273    SC->ForgetSema();
274
275  // Detach from the external Sema source.
276  if (ExternalSemaSource *ExternalSema
277        = dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
278    ExternalSema->ForgetSema();
279
280  // If Sema's ExternalSource is the multiplexer - we own it.
281  if (isMultiplexExternalSource)
282    delete ExternalSource;
283
284  threadSafety::threadSafetyCleanup(ThreadSafetyDeclCache);
285
286  // Destroys data sharing attributes stack for OpenMP
287  DestroyDataSharingAttributesStack();
288
289  assert(DelayedTypos.empty() && "Uncorrected typos!");
290}
291
292/// makeUnavailableInSystemHeader - There is an error in the current
293/// context.  If we're still in a system header, and we can plausibly
294/// make the relevant declaration unavailable instead of erroring, do
295/// so and return true.
296bool Sema::makeUnavailableInSystemHeader(SourceLocation loc,
297                                      UnavailableAttr::ImplicitReason reason) {
298  // If we're not in a function, it's an error.
299  FunctionDecl *fn = dyn_cast<FunctionDecl>(CurContext);
300  if (!fn) return false;
301
302  // If we're in template instantiation, it's an error.
303  if (!ActiveTemplateInstantiations.empty())
304    return false;
305
306  // If that function's not in a system header, it's an error.
307  if (!Context.getSourceManager().isInSystemHeader(loc))
308    return false;
309
310  // If the function is already unavailable, it's not an error.
311  if (fn->hasAttr<UnavailableAttr>()) return true;
312
313  fn->addAttr(UnavailableAttr::CreateImplicit(Context, "", reason, loc));
314  return true;
315}
316
317ASTMutationListener *Sema::getASTMutationListener() const {
318  return getASTConsumer().GetASTMutationListener();
319}
320
321///\brief Registers an external source. If an external source already exists,
322/// creates a multiplex external source and appends to it.
323///
324///\param[in] E - A non-null external sema source.
325///
326void Sema::addExternalSource(ExternalSemaSource *E) {
327  assert(E && "Cannot use with NULL ptr");
328
329  if (!ExternalSource) {
330    ExternalSource = E;
331    return;
332  }
333
334  if (isMultiplexExternalSource)
335    static_cast<MultiplexExternalSemaSource*>(ExternalSource)->addSource(*E);
336  else {
337    ExternalSource = new MultiplexExternalSemaSource(*ExternalSource, *E);
338    isMultiplexExternalSource = true;
339  }
340}
341
342/// \brief Print out statistics about the semantic analysis.
343void Sema::PrintStats() const {
344  llvm::errs() << "\n*** Semantic Analysis Stats:\n";
345  llvm::errs() << NumSFINAEErrors << " SFINAE diagnostics trapped.\n";
346
347  BumpAlloc.PrintStats();
348  AnalysisWarnings.PrintStats();
349}
350
351void Sema::diagnoseNullableToNonnullConversion(QualType DstType,
352                                               QualType SrcType,
353                                               SourceLocation Loc) {
354  Optional<NullabilityKind> ExprNullability = SrcType->getNullability(Context);
355  if (!ExprNullability || *ExprNullability != NullabilityKind::Nullable)
356    return;
357
358  Optional<NullabilityKind> TypeNullability = DstType->getNullability(Context);
359  if (!TypeNullability || *TypeNullability != NullabilityKind::NonNull)
360    return;
361
362  Diag(Loc, diag::warn_nullability_lost) << SrcType << DstType;
363}
364
365/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast.
366/// If there is already an implicit cast, merge into the existing one.
367/// The result is of the given category.
368ExprResult Sema::ImpCastExprToType(Expr *E, QualType Ty,
369                                   CastKind Kind, ExprValueKind VK,
370                                   const CXXCastPath *BasePath,
371                                   CheckedConversionKind CCK) {
372#ifndef NDEBUG
373  if (VK == VK_RValue && !E->isRValue()) {
374    switch (Kind) {
375    default:
376      llvm_unreachable("can't implicitly cast lvalue to rvalue with this cast "
377                       "kind");
378    case CK_LValueToRValue:
379    case CK_ArrayToPointerDecay:
380    case CK_FunctionToPointerDecay:
381    case CK_ToVoid:
382      break;
383    }
384  }
385  assert((VK == VK_RValue || !E->isRValue()) && "can't cast rvalue to lvalue");
386#endif
387
388  diagnoseNullableToNonnullConversion(Ty, E->getType(), E->getLocStart());
389
390  QualType ExprTy = Context.getCanonicalType(E->getType());
391  QualType TypeTy = Context.getCanonicalType(Ty);
392
393  if (ExprTy == TypeTy)
394    return E;
395
396  if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(E)) {
397    if (ImpCast->getCastKind() == Kind && (!BasePath || BasePath->empty())) {
398      ImpCast->setType(Ty);
399      ImpCast->setValueKind(VK);
400      return E;
401    }
402  }
403
404  return ImplicitCastExpr::Create(Context, Ty, Kind, E, BasePath, VK);
405}
406
407/// ScalarTypeToBooleanCastKind - Returns the cast kind corresponding
408/// to the conversion from scalar type ScalarTy to the Boolean type.
409CastKind Sema::ScalarTypeToBooleanCastKind(QualType ScalarTy) {
410  switch (ScalarTy->getScalarTypeKind()) {
411  case Type::STK_Bool: return CK_NoOp;
412  case Type::STK_CPointer: return CK_PointerToBoolean;
413  case Type::STK_BlockPointer: return CK_PointerToBoolean;
414  case Type::STK_ObjCObjectPointer: return CK_PointerToBoolean;
415  case Type::STK_MemberPointer: return CK_MemberPointerToBoolean;
416  case Type::STK_Integral: return CK_IntegralToBoolean;
417  case Type::STK_Floating: return CK_FloatingToBoolean;
418  case Type::STK_IntegralComplex: return CK_IntegralComplexToBoolean;
419  case Type::STK_FloatingComplex: return CK_FloatingComplexToBoolean;
420  }
421  return CK_Invalid;
422}
423
424/// \brief Used to prune the decls of Sema's UnusedFileScopedDecls vector.
425static bool ShouldRemoveFromUnused(Sema *SemaRef, const DeclaratorDecl *D) {
426  if (D->getMostRecentDecl()->isUsed())
427    return true;
428
429  if (D->isExternallyVisible())
430    return true;
431
432  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
433    // UnusedFileScopedDecls stores the first declaration.
434    // The declaration may have become definition so check again.
435    const FunctionDecl *DeclToCheck;
436    if (FD->hasBody(DeclToCheck))
437      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
438
439    // Later redecls may add new information resulting in not having to warn,
440    // so check again.
441    DeclToCheck = FD->getMostRecentDecl();
442    if (DeclToCheck != FD)
443      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
444  }
445
446  if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
447    // If a variable usable in constant expressions is referenced,
448    // don't warn if it isn't used: if the value of a variable is required
449    // for the computation of a constant expression, it doesn't make sense to
450    // warn even if the variable isn't odr-used.  (isReferenced doesn't
451    // precisely reflect that, but it's a decent approximation.)
452    if (VD->isReferenced() &&
453        VD->isUsableInConstantExpressions(SemaRef->Context))
454      return true;
455
456    // UnusedFileScopedDecls stores the first declaration.
457    // The declaration may have become definition so check again.
458    const VarDecl *DeclToCheck = VD->getDefinition();
459    if (DeclToCheck)
460      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
461
462    // Later redecls may add new information resulting in not having to warn,
463    // so check again.
464    DeclToCheck = VD->getMostRecentDecl();
465    if (DeclToCheck != VD)
466      return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
467  }
468
469  return false;
470}
471
472/// Obtains a sorted list of functions and variables that are undefined but
473/// ODR-used.
474void Sema::getUndefinedButUsed(
475    SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> > &Undefined) {
476  for (const auto &UndefinedUse : UndefinedButUsed) {
477    NamedDecl *ND = UndefinedUse.first;
478
479    // Ignore attributes that have become invalid.
480    if (ND->isInvalidDecl()) continue;
481
482    // __attribute__((weakref)) is basically a definition.
483    if (ND->hasAttr<WeakRefAttr>()) continue;
484
485    if (FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
486      if (FD->isDefined())
487        continue;
488      if (FD->isExternallyVisible() &&
489          !FD->getMostRecentDecl()->isInlined())
490        continue;
491    } else {
492      auto *VD = cast<VarDecl>(ND);
493      if (VD->hasDefinition() != VarDecl::DeclarationOnly)
494        continue;
495      if (VD->isExternallyVisible() && !VD->getMostRecentDecl()->isInline())
496        continue;
497    }
498
499    Undefined.push_back(std::make_pair(ND, UndefinedUse.second));
500  }
501}
502
503/// checkUndefinedButUsed - Check for undefined objects with internal linkage
504/// or that are inline.
505static void checkUndefinedButUsed(Sema &S) {
506  if (S.UndefinedButUsed.empty()) return;
507
508  // Collect all the still-undefined entities with internal linkage.
509  SmallVector<std::pair<NamedDecl *, SourceLocation>, 16> Undefined;
510  S.getUndefinedButUsed(Undefined);
511  if (Undefined.empty()) return;
512
513  for (SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> >::iterator
514         I = Undefined.begin(), E = Undefined.end(); I != E; ++I) {
515    NamedDecl *ND = I->first;
516
517    if (ND->hasAttr<DLLImportAttr>() || ND->hasAttr<DLLExportAttr>()) {
518      // An exported function will always be emitted when defined, so even if
519      // the function is inline, it doesn't have to be emitted in this TU. An
520      // imported function implies that it has been exported somewhere else.
521      continue;
522    }
523
524    if (!ND->isExternallyVisible()) {
525      S.Diag(ND->getLocation(), diag::warn_undefined_internal)
526        << isa<VarDecl>(ND) << ND;
527    } else if (auto *FD = dyn_cast<FunctionDecl>(ND)) {
528      (void)FD;
529      assert(FD->getMostRecentDecl()->isInlined() &&
530             "used object requires definition but isn't inline or internal?");
531      // FIXME: This is ill-formed; we should reject.
532      S.Diag(ND->getLocation(), diag::warn_undefined_inline) << ND;
533    } else {
534      assert(cast<VarDecl>(ND)->getMostRecentDecl()->isInline() &&
535             "used var requires definition but isn't inline or internal?");
536      S.Diag(ND->getLocation(), diag::err_undefined_inline_var) << ND;
537    }
538    if (I->second.isValid())
539      S.Diag(I->second, diag::note_used_here);
540  }
541
542  S.UndefinedButUsed.clear();
543}
544
545void Sema::LoadExternalWeakUndeclaredIdentifiers() {
546  if (!ExternalSource)
547    return;
548
549  SmallVector<std::pair<IdentifierInfo *, WeakInfo>, 4> WeakIDs;
550  ExternalSource->ReadWeakUndeclaredIdentifiers(WeakIDs);
551  for (auto &WeakID : WeakIDs)
552    WeakUndeclaredIdentifiers.insert(WeakID);
553}
554
555
556typedef llvm::DenseMap<const CXXRecordDecl*, bool> RecordCompleteMap;
557
558/// \brief Returns true, if all methods and nested classes of the given
559/// CXXRecordDecl are defined in this translation unit.
560///
561/// Should only be called from ActOnEndOfTranslationUnit so that all
562/// definitions are actually read.
563static bool MethodsAndNestedClassesComplete(const CXXRecordDecl *RD,
564                                            RecordCompleteMap &MNCComplete) {
565  RecordCompleteMap::iterator Cache = MNCComplete.find(RD);
566  if (Cache != MNCComplete.end())
567    return Cache->second;
568  if (!RD->isCompleteDefinition())
569    return false;
570  bool Complete = true;
571  for (DeclContext::decl_iterator I = RD->decls_begin(),
572                                  E = RD->decls_end();
573       I != E && Complete; ++I) {
574    if (const CXXMethodDecl *M = dyn_cast<CXXMethodDecl>(*I))
575      Complete = M->isDefined() || (M->isPure() && !isa<CXXDestructorDecl>(M));
576    else if (const FunctionTemplateDecl *F = dyn_cast<FunctionTemplateDecl>(*I))
577      // If the template function is marked as late template parsed at this
578      // point, it has not been instantiated and therefore we have not
579      // performed semantic analysis on it yet, so we cannot know if the type
580      // can be considered complete.
581      Complete = !F->getTemplatedDecl()->isLateTemplateParsed() &&
582                  F->getTemplatedDecl()->isDefined();
583    else if (const CXXRecordDecl *R = dyn_cast<CXXRecordDecl>(*I)) {
584      if (R->isInjectedClassName())
585        continue;
586      if (R->hasDefinition())
587        Complete = MethodsAndNestedClassesComplete(R->getDefinition(),
588                                                   MNCComplete);
589      else
590        Complete = false;
591    }
592  }
593  MNCComplete[RD] = Complete;
594  return Complete;
595}
596
597/// \brief Returns true, if the given CXXRecordDecl is fully defined in this
598/// translation unit, i.e. all methods are defined or pure virtual and all
599/// friends, friend functions and nested classes are fully defined in this
600/// translation unit.
601///
602/// Should only be called from ActOnEndOfTranslationUnit so that all
603/// definitions are actually read.
604static bool IsRecordFullyDefined(const CXXRecordDecl *RD,
605                                 RecordCompleteMap &RecordsComplete,
606                                 RecordCompleteMap &MNCComplete) {
607  RecordCompleteMap::iterator Cache = RecordsComplete.find(RD);
608  if (Cache != RecordsComplete.end())
609    return Cache->second;
610  bool Complete = MethodsAndNestedClassesComplete(RD, MNCComplete);
611  for (CXXRecordDecl::friend_iterator I = RD->friend_begin(),
612                                      E = RD->friend_end();
613       I != E && Complete; ++I) {
614    // Check if friend classes and methods are complete.
615    if (TypeSourceInfo *TSI = (*I)->getFriendType()) {
616      // Friend classes are available as the TypeSourceInfo of the FriendDecl.
617      if (CXXRecordDecl *FriendD = TSI->getType()->getAsCXXRecordDecl())
618        Complete = MethodsAndNestedClassesComplete(FriendD, MNCComplete);
619      else
620        Complete = false;
621    } else {
622      // Friend functions are available through the NamedDecl of FriendDecl.
623      if (const FunctionDecl *FD =
624          dyn_cast<FunctionDecl>((*I)->getFriendDecl()))
625        Complete = FD->isDefined();
626      else
627        // This is a template friend, give up.
628        Complete = false;
629    }
630  }
631  RecordsComplete[RD] = Complete;
632  return Complete;
633}
634
635void Sema::emitAndClearUnusedLocalTypedefWarnings() {
636  if (ExternalSource)
637    ExternalSource->ReadUnusedLocalTypedefNameCandidates(
638        UnusedLocalTypedefNameCandidates);
639  for (const TypedefNameDecl *TD : UnusedLocalTypedefNameCandidates) {
640    if (TD->isReferenced())
641      continue;
642    Diag(TD->getLocation(), diag::warn_unused_local_typedef)
643        << isa<TypeAliasDecl>(TD) << TD->getDeclName();
644  }
645  UnusedLocalTypedefNameCandidates.clear();
646}
647
648/// ActOnEndOfTranslationUnit - This is called at the very end of the
649/// translation unit when EOF is reached and all but the top-level scope is
650/// popped.
651void Sema::ActOnEndOfTranslationUnit() {
652  assert(DelayedDiagnostics.getCurrentPool() == nullptr
653         && "reached end of translation unit with a pool attached?");
654
655  // If code completion is enabled, don't perform any end-of-translation-unit
656  // work.
657  if (PP.isCodeCompletionEnabled())
658    return;
659
660  // Complete translation units and modules define vtables and perform implicit
661  // instantiations. PCH files do not.
662  if (TUKind != TU_Prefix) {
663    DiagnoseUseOfUnimplementedSelectors();
664
665    // If DefinedUsedVTables ends up marking any virtual member functions it
666    // might lead to more pending template instantiations, which we then need
667    // to instantiate.
668    DefineUsedVTables();
669
670    // C++: Perform implicit template instantiations.
671    //
672    // FIXME: When we perform these implicit instantiations, we do not
673    // carefully keep track of the point of instantiation (C++ [temp.point]).
674    // This means that name lookup that occurs within the template
675    // instantiation will always happen at the end of the translation unit,
676    // so it will find some names that are not required to be found. This is
677    // valid, but we could do better by diagnosing if an instantiation uses a
678    // name that was not visible at its first point of instantiation.
679    if (ExternalSource) {
680      // Load pending instantiations from the external source.
681      SmallVector<PendingImplicitInstantiation, 4> Pending;
682      ExternalSource->ReadPendingInstantiations(Pending);
683      PendingInstantiations.insert(PendingInstantiations.begin(),
684                                   Pending.begin(), Pending.end());
685    }
686    PerformPendingInstantiations();
687
688    if (LateTemplateParserCleanup)
689      LateTemplateParserCleanup(OpaqueParser);
690
691    CheckDelayedMemberExceptionSpecs();
692  }
693
694  // All delayed member exception specs should be checked or we end up accepting
695  // incompatible declarations.
696  // FIXME: This is wrong for TUKind == TU_Prefix. In that case, we need to
697  // write out the lists to the AST file (if any).
698  assert(DelayedDefaultedMemberExceptionSpecs.empty());
699  assert(DelayedExceptionSpecChecks.empty());
700
701  // All dllexport classes should have been processed already.
702  assert(DelayedDllExportClasses.empty());
703
704  // Remove file scoped decls that turned out to be used.
705  UnusedFileScopedDecls.erase(
706      std::remove_if(UnusedFileScopedDecls.begin(nullptr, true),
707                     UnusedFileScopedDecls.end(),
708                     std::bind1st(std::ptr_fun(ShouldRemoveFromUnused), this)),
709      UnusedFileScopedDecls.end());
710
711  if (TUKind == TU_Prefix) {
712    // Translation unit prefixes don't need any of the checking below.
713    TUScope = nullptr;
714    return;
715  }
716
717  // Check for #pragma weak identifiers that were never declared
718  LoadExternalWeakUndeclaredIdentifiers();
719  for (auto WeakID : WeakUndeclaredIdentifiers) {
720    if (WeakID.second.getUsed())
721      continue;
722
723    Decl *PrevDecl = LookupSingleName(TUScope, WeakID.first, SourceLocation(),
724                                      LookupOrdinaryName);
725    if (PrevDecl != nullptr &&
726        !(isa<FunctionDecl>(PrevDecl) || isa<VarDecl>(PrevDecl)))
727      Diag(WeakID.second.getLocation(), diag::warn_attribute_wrong_decl_type)
728          << "'weak'" << ExpectedVariableOrFunction;
729    else
730      Diag(WeakID.second.getLocation(), diag::warn_weak_identifier_undeclared)
731          << WeakID.first;
732  }
733
734  if (LangOpts.CPlusPlus11 &&
735      !Diags.isIgnored(diag::warn_delegating_ctor_cycle, SourceLocation()))
736    CheckDelegatingCtorCycles();
737
738  if (!Diags.hasErrorOccurred()) {
739    if (ExternalSource)
740      ExternalSource->ReadUndefinedButUsed(UndefinedButUsed);
741    checkUndefinedButUsed(*this);
742  }
743
744  if (TUKind == TU_Module) {
745    // If we are building a module, resolve all of the exported declarations
746    // now.
747    if (Module *CurrentModule = PP.getCurrentModule()) {
748      ModuleMap &ModMap = PP.getHeaderSearchInfo().getModuleMap();
749
750      SmallVector<Module *, 2> Stack;
751      Stack.push_back(CurrentModule);
752      while (!Stack.empty()) {
753        Module *Mod = Stack.pop_back_val();
754
755        // Resolve the exported declarations and conflicts.
756        // FIXME: Actually complain, once we figure out how to teach the
757        // diagnostic client to deal with complaints in the module map at this
758        // point.
759        ModMap.resolveExports(Mod, /*Complain=*/false);
760        ModMap.resolveUses(Mod, /*Complain=*/false);
761        ModMap.resolveConflicts(Mod, /*Complain=*/false);
762
763        // Queue the submodules, so their exports will also be resolved.
764        Stack.append(Mod->submodule_begin(), Mod->submodule_end());
765      }
766    }
767
768    // Warnings emitted in ActOnEndOfTranslationUnit() should be emitted for
769    // modules when they are built, not every time they are used.
770    emitAndClearUnusedLocalTypedefWarnings();
771
772    // Modules don't need any of the checking below.
773    TUScope = nullptr;
774    return;
775  }
776
777  // C99 6.9.2p2:
778  //   A declaration of an identifier for an object that has file
779  //   scope without an initializer, and without a storage-class
780  //   specifier or with the storage-class specifier static,
781  //   constitutes a tentative definition. If a translation unit
782  //   contains one or more tentative definitions for an identifier,
783  //   and the translation unit contains no external definition for
784  //   that identifier, then the behavior is exactly as if the
785  //   translation unit contains a file scope declaration of that
786  //   identifier, with the composite type as of the end of the
787  //   translation unit, with an initializer equal to 0.
788  llvm::SmallSet<VarDecl *, 32> Seen;
789  for (TentativeDefinitionsType::iterator
790            T = TentativeDefinitions.begin(ExternalSource),
791         TEnd = TentativeDefinitions.end();
792       T != TEnd; ++T)
793  {
794    VarDecl *VD = (*T)->getActingDefinition();
795
796    // If the tentative definition was completed, getActingDefinition() returns
797    // null. If we've already seen this variable before, insert()'s second
798    // return value is false.
799    if (!VD || VD->isInvalidDecl() || !Seen.insert(VD).second)
800      continue;
801
802    if (const IncompleteArrayType *ArrayT
803        = Context.getAsIncompleteArrayType(VD->getType())) {
804      // Set the length of the array to 1 (C99 6.9.2p5).
805      Diag(VD->getLocation(), diag::warn_tentative_incomplete_array);
806      llvm::APInt One(Context.getTypeSize(Context.getSizeType()), true);
807      QualType T = Context.getConstantArrayType(ArrayT->getElementType(),
808                                                One, ArrayType::Normal, 0);
809      VD->setType(T);
810    } else if (RequireCompleteType(VD->getLocation(), VD->getType(),
811                                   diag::err_tentative_def_incomplete_type))
812      VD->setInvalidDecl();
813
814    CheckCompleteVariableDeclaration(VD);
815
816    // Notify the consumer that we've completed a tentative definition.
817    if (!VD->isInvalidDecl())
818      Consumer.CompleteTentativeDefinition(VD);
819
820  }
821
822  // If there were errors, disable 'unused' warnings since they will mostly be
823  // noise.
824  if (!Diags.hasErrorOccurred()) {
825    // Output warning for unused file scoped decls.
826    for (UnusedFileScopedDeclsType::iterator
827           I = UnusedFileScopedDecls.begin(ExternalSource),
828           E = UnusedFileScopedDecls.end(); I != E; ++I) {
829      if (ShouldRemoveFromUnused(this, *I))
830        continue;
831
832      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) {
833        const FunctionDecl *DiagD;
834        if (!FD->hasBody(DiagD))
835          DiagD = FD;
836        if (DiagD->isDeleted())
837          continue; // Deleted functions are supposed to be unused.
838        if (DiagD->isReferenced()) {
839          if (isa<CXXMethodDecl>(DiagD))
840            Diag(DiagD->getLocation(), diag::warn_unneeded_member_function)
841                  << DiagD->getDeclName();
842          else {
843            if (FD->getStorageClass() == SC_Static &&
844                !FD->isInlineSpecified() &&
845                !SourceMgr.isInMainFile(
846                   SourceMgr.getExpansionLoc(FD->getLocation())))
847              Diag(DiagD->getLocation(),
848                   diag::warn_unneeded_static_internal_decl)
849                  << DiagD->getDeclName();
850            else
851              Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
852                   << /*function*/0 << DiagD->getDeclName();
853          }
854        } else {
855          Diag(DiagD->getLocation(),
856               isa<CXXMethodDecl>(DiagD) ? diag::warn_unused_member_function
857                                         : diag::warn_unused_function)
858                << DiagD->getDeclName();
859        }
860      } else {
861        const VarDecl *DiagD = cast<VarDecl>(*I)->getDefinition();
862        if (!DiagD)
863          DiagD = cast<VarDecl>(*I);
864        if (DiagD->isReferenced()) {
865          Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
866                << /*variable*/1 << DiagD->getDeclName();
867        } else if (DiagD->getType().isConstQualified()) {
868          Diag(DiagD->getLocation(), diag::warn_unused_const_variable)
869              << DiagD->getDeclName();
870        } else {
871          Diag(DiagD->getLocation(), diag::warn_unused_variable)
872              << DiagD->getDeclName();
873        }
874      }
875    }
876
877    emitAndClearUnusedLocalTypedefWarnings();
878  }
879
880  if (!Diags.isIgnored(diag::warn_unused_private_field, SourceLocation())) {
881    RecordCompleteMap RecordsComplete;
882    RecordCompleteMap MNCComplete;
883    for (NamedDeclSetType::iterator I = UnusedPrivateFields.begin(),
884         E = UnusedPrivateFields.end(); I != E; ++I) {
885      const NamedDecl *D = *I;
886      const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D->getDeclContext());
887      if (RD && !RD->isUnion() &&
888          IsRecordFullyDefined(RD, RecordsComplete, MNCComplete)) {
889        Diag(D->getLocation(), diag::warn_unused_private_field)
890              << D->getDeclName();
891      }
892    }
893  }
894
895  if (!Diags.isIgnored(diag::warn_mismatched_delete_new, SourceLocation())) {
896    if (ExternalSource)
897      ExternalSource->ReadMismatchingDeleteExpressions(DeleteExprs);
898    for (const auto &DeletedFieldInfo : DeleteExprs) {
899      for (const auto &DeleteExprLoc : DeletedFieldInfo.second) {
900        AnalyzeDeleteExprMismatch(DeletedFieldInfo.first, DeleteExprLoc.first,
901                                  DeleteExprLoc.second);
902      }
903    }
904  }
905
906  // Check we've noticed that we're no longer parsing the initializer for every
907  // variable. If we miss cases, then at best we have a performance issue and
908  // at worst a rejects-valid bug.
909  assert(ParsingInitForAutoVars.empty() &&
910         "Didn't unmark var as having its initializer parsed");
911
912  TUScope = nullptr;
913}
914
915
916//===----------------------------------------------------------------------===//
917// Helper functions.
918//===----------------------------------------------------------------------===//
919
920DeclContext *Sema::getFunctionLevelDeclContext() {
921  DeclContext *DC = CurContext;
922
923  while (true) {
924    if (isa<BlockDecl>(DC) || isa<EnumDecl>(DC) || isa<CapturedDecl>(DC)) {
925      DC = DC->getParent();
926    } else if (isa<CXXMethodDecl>(DC) &&
927               cast<CXXMethodDecl>(DC)->getOverloadedOperator() == OO_Call &&
928               cast<CXXRecordDecl>(DC->getParent())->isLambda()) {
929      DC = DC->getParent()->getParent();
930    }
931    else break;
932  }
933
934  return DC;
935}
936
937/// getCurFunctionDecl - If inside of a function body, this returns a pointer
938/// to the function decl for the function being parsed.  If we're currently
939/// in a 'block', this returns the containing context.
940FunctionDecl *Sema::getCurFunctionDecl() {
941  DeclContext *DC = getFunctionLevelDeclContext();
942  return dyn_cast<FunctionDecl>(DC);
943}
944
945ObjCMethodDecl *Sema::getCurMethodDecl() {
946  DeclContext *DC = getFunctionLevelDeclContext();
947  while (isa<RecordDecl>(DC))
948    DC = DC->getParent();
949  return dyn_cast<ObjCMethodDecl>(DC);
950}
951
952NamedDecl *Sema::getCurFunctionOrMethodDecl() {
953  DeclContext *DC = getFunctionLevelDeclContext();
954  if (isa<ObjCMethodDecl>(DC) || isa<FunctionDecl>(DC))
955    return cast<NamedDecl>(DC);
956  return nullptr;
957}
958
959void Sema::EmitCurrentDiagnostic(unsigned DiagID) {
960  // FIXME: It doesn't make sense to me that DiagID is an incoming argument here
961  // and yet we also use the current diag ID on the DiagnosticsEngine. This has
962  // been made more painfully obvious by the refactor that introduced this
963  // function, but it is possible that the incoming argument can be
964  // eliminnated. If it truly cannot be (for example, there is some reentrancy
965  // issue I am not seeing yet), then there should at least be a clarifying
966  // comment somewhere.
967  if (Optional<TemplateDeductionInfo*> Info = isSFINAEContext()) {
968    switch (DiagnosticIDs::getDiagnosticSFINAEResponse(
969              Diags.getCurrentDiagID())) {
970    case DiagnosticIDs::SFINAE_Report:
971      // We'll report the diagnostic below.
972      break;
973
974    case DiagnosticIDs::SFINAE_SubstitutionFailure:
975      // Count this failure so that we know that template argument deduction
976      // has failed.
977      ++NumSFINAEErrors;
978
979      // Make a copy of this suppressed diagnostic and store it with the
980      // template-deduction information.
981      if (*Info && !(*Info)->hasSFINAEDiagnostic()) {
982        Diagnostic DiagInfo(&Diags);
983        (*Info)->addSFINAEDiagnostic(DiagInfo.getLocation(),
984                       PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
985      }
986
987      Diags.setLastDiagnosticIgnored();
988      Diags.Clear();
989      return;
990
991    case DiagnosticIDs::SFINAE_AccessControl: {
992      // Per C++ Core Issue 1170, access control is part of SFINAE.
993      // Additionally, the AccessCheckingSFINAE flag can be used to temporarily
994      // make access control a part of SFINAE for the purposes of checking
995      // type traits.
996      if (!AccessCheckingSFINAE && !getLangOpts().CPlusPlus11)
997        break;
998
999      SourceLocation Loc = Diags.getCurrentDiagLoc();
1000
1001      // Suppress this diagnostic.
1002      ++NumSFINAEErrors;
1003
1004      // Make a copy of this suppressed diagnostic and store it with the
1005      // template-deduction information.
1006      if (*Info && !(*Info)->hasSFINAEDiagnostic()) {
1007        Diagnostic DiagInfo(&Diags);
1008        (*Info)->addSFINAEDiagnostic(DiagInfo.getLocation(),
1009                       PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
1010      }
1011
1012      Diags.setLastDiagnosticIgnored();
1013      Diags.Clear();
1014
1015      // Now the diagnostic state is clear, produce a C++98 compatibility
1016      // warning.
1017      Diag(Loc, diag::warn_cxx98_compat_sfinae_access_control);
1018
1019      // The last diagnostic which Sema produced was ignored. Suppress any
1020      // notes attached to it.
1021      Diags.setLastDiagnosticIgnored();
1022      return;
1023    }
1024
1025    case DiagnosticIDs::SFINAE_Suppress:
1026      // Make a copy of this suppressed diagnostic and store it with the
1027      // template-deduction information;
1028      if (*Info) {
1029        Diagnostic DiagInfo(&Diags);
1030        (*Info)->addSuppressedDiagnostic(DiagInfo.getLocation(),
1031                       PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
1032      }
1033
1034      // Suppress this diagnostic.
1035      Diags.setLastDiagnosticIgnored();
1036      Diags.Clear();
1037      return;
1038    }
1039  }
1040
1041  // Set up the context's printing policy based on our current state.
1042  Context.setPrintingPolicy(getPrintingPolicy());
1043
1044  // Emit the diagnostic.
1045  if (!Diags.EmitCurrentDiagnostic())
1046    return;
1047
1048  // If this is not a note, and we're in a template instantiation
1049  // that is different from the last template instantiation where
1050  // we emitted an error, print a template instantiation
1051  // backtrace.
1052  if (!DiagnosticIDs::isBuiltinNote(DiagID) &&
1053      !ActiveTemplateInstantiations.empty() &&
1054      ActiveTemplateInstantiations.back()
1055        != LastTemplateInstantiationErrorContext) {
1056    PrintInstantiationStack();
1057    LastTemplateInstantiationErrorContext = ActiveTemplateInstantiations.back();
1058  }
1059}
1060
1061Sema::SemaDiagnosticBuilder
1062Sema::Diag(SourceLocation Loc, const PartialDiagnostic& PD) {
1063  SemaDiagnosticBuilder Builder(Diag(Loc, PD.getDiagID()));
1064  PD.Emit(Builder);
1065
1066  return Builder;
1067}
1068
1069/// \brief Looks through the macro-expansion chain for the given
1070/// location, looking for a macro expansion with the given name.
1071/// If one is found, returns true and sets the location to that
1072/// expansion loc.
1073bool Sema::findMacroSpelling(SourceLocation &locref, StringRef name) {
1074  SourceLocation loc = locref;
1075  if (!loc.isMacroID()) return false;
1076
1077  // There's no good way right now to look at the intermediate
1078  // expansions, so just jump to the expansion location.
1079  loc = getSourceManager().getExpansionLoc(loc);
1080
1081  // If that's written with the name, stop here.
1082  SmallVector<char, 16> buffer;
1083  if (getPreprocessor().getSpelling(loc, buffer) == name) {
1084    locref = loc;
1085    return true;
1086  }
1087  return false;
1088}
1089
1090/// \brief Determines the active Scope associated with the given declaration
1091/// context.
1092///
1093/// This routine maps a declaration context to the active Scope object that
1094/// represents that declaration context in the parser. It is typically used
1095/// from "scope-less" code (e.g., template instantiation, lazy creation of
1096/// declarations) that injects a name for name-lookup purposes and, therefore,
1097/// must update the Scope.
1098///
1099/// \returns The scope corresponding to the given declaraion context, or NULL
1100/// if no such scope is open.
1101Scope *Sema::getScopeForContext(DeclContext *Ctx) {
1102
1103  if (!Ctx)
1104    return nullptr;
1105
1106  Ctx = Ctx->getPrimaryContext();
1107  for (Scope *S = getCurScope(); S; S = S->getParent()) {
1108    // Ignore scopes that cannot have declarations. This is important for
1109    // out-of-line definitions of static class members.
1110    if (S->getFlags() & (Scope::DeclScope | Scope::TemplateParamScope))
1111      if (DeclContext *Entity = S->getEntity())
1112        if (Ctx == Entity->getPrimaryContext())
1113          return S;
1114  }
1115
1116  return nullptr;
1117}
1118
1119/// \brief Enter a new function scope
1120void Sema::PushFunctionScope() {
1121  if (FunctionScopes.size() == 1) {
1122    // Use the "top" function scope rather than having to allocate
1123    // memory for a new scope.
1124    FunctionScopes.back()->Clear();
1125    FunctionScopes.push_back(FunctionScopes.back());
1126    return;
1127  }
1128
1129  FunctionScopes.push_back(new FunctionScopeInfo(getDiagnostics()));
1130}
1131
1132void Sema::PushBlockScope(Scope *BlockScope, BlockDecl *Block) {
1133  FunctionScopes.push_back(new BlockScopeInfo(getDiagnostics(),
1134                                              BlockScope, Block));
1135}
1136
1137LambdaScopeInfo *Sema::PushLambdaScope() {
1138  LambdaScopeInfo *const LSI = new LambdaScopeInfo(getDiagnostics());
1139  FunctionScopes.push_back(LSI);
1140  return LSI;
1141}
1142
1143void Sema::RecordParsingTemplateParameterDepth(unsigned Depth) {
1144  if (LambdaScopeInfo *const LSI = getCurLambda()) {
1145    LSI->AutoTemplateParameterDepth = Depth;
1146    return;
1147  }
1148  llvm_unreachable(
1149      "Remove assertion if intentionally called in a non-lambda context.");
1150}
1151
1152void Sema::PopFunctionScopeInfo(const AnalysisBasedWarnings::Policy *WP,
1153                                const Decl *D, const BlockExpr *blkExpr) {
1154  FunctionScopeInfo *Scope = FunctionScopes.pop_back_val();
1155  assert(!FunctionScopes.empty() && "mismatched push/pop!");
1156
1157  // Issue any analysis-based warnings.
1158  if (WP && D)
1159    AnalysisWarnings.IssueWarnings(*WP, Scope, D, blkExpr);
1160  else
1161    for (const auto &PUD : Scope->PossiblyUnreachableDiags)
1162      Diag(PUD.Loc, PUD.PD);
1163
1164  if (FunctionScopes.back() != Scope)
1165    delete Scope;
1166}
1167
1168void Sema::PushCompoundScope() {
1169  getCurFunction()->CompoundScopes.push_back(CompoundScopeInfo());
1170}
1171
1172void Sema::PopCompoundScope() {
1173  FunctionScopeInfo *CurFunction = getCurFunction();
1174  assert(!CurFunction->CompoundScopes.empty() && "mismatched push/pop");
1175
1176  CurFunction->CompoundScopes.pop_back();
1177}
1178
1179/// \brief Determine whether any errors occurred within this function/method/
1180/// block.
1181bool Sema::hasAnyUnrecoverableErrorsInThisFunction() const {
1182  return getCurFunction()->ErrorTrap.hasUnrecoverableErrorOccurred();
1183}
1184
1185BlockScopeInfo *Sema::getCurBlock() {
1186  if (FunctionScopes.empty())
1187    return nullptr;
1188
1189  auto CurBSI = dyn_cast<BlockScopeInfo>(FunctionScopes.back());
1190  if (CurBSI && CurBSI->TheDecl &&
1191      !CurBSI->TheDecl->Encloses(CurContext)) {
1192    // We have switched contexts due to template instantiation.
1193    assert(!ActiveTemplateInstantiations.empty());
1194    return nullptr;
1195  }
1196
1197  return CurBSI;
1198}
1199
1200LambdaScopeInfo *Sema::getCurLambda() {
1201  if (FunctionScopes.empty())
1202    return nullptr;
1203
1204  auto CurLSI = dyn_cast<LambdaScopeInfo>(FunctionScopes.back());
1205  if (CurLSI && CurLSI->Lambda &&
1206      !CurLSI->Lambda->Encloses(CurContext)) {
1207    // We have switched contexts due to template instantiation.
1208    assert(!ActiveTemplateInstantiations.empty());
1209    return nullptr;
1210  }
1211
1212  return CurLSI;
1213}
1214// We have a generic lambda if we parsed auto parameters, or we have
1215// an associated template parameter list.
1216LambdaScopeInfo *Sema::getCurGenericLambda() {
1217  if (LambdaScopeInfo *LSI =  getCurLambda()) {
1218    return (LSI->AutoTemplateParams.size() ||
1219                    LSI->GLTemplateParameterList) ? LSI : nullptr;
1220  }
1221  return nullptr;
1222}
1223
1224
1225void Sema::ActOnComment(SourceRange Comment) {
1226  if (!LangOpts.RetainCommentsFromSystemHeaders &&
1227      SourceMgr.isInSystemHeader(Comment.getBegin()))
1228    return;
1229  RawComment RC(SourceMgr, Comment, false,
1230                LangOpts.CommentOpts.ParseAllComments);
1231  if (RC.isAlmostTrailingComment()) {
1232    SourceRange MagicMarkerRange(Comment.getBegin(),
1233                                 Comment.getBegin().getLocWithOffset(3));
1234    StringRef MagicMarkerText;
1235    switch (RC.getKind()) {
1236    case RawComment::RCK_OrdinaryBCPL:
1237      MagicMarkerText = "///<";
1238      break;
1239    case RawComment::RCK_OrdinaryC:
1240      MagicMarkerText = "/**<";
1241      break;
1242    default:
1243      llvm_unreachable("if this is an almost Doxygen comment, "
1244                       "it should be ordinary");
1245    }
1246    Diag(Comment.getBegin(), diag::warn_not_a_doxygen_trailing_member_comment) <<
1247      FixItHint::CreateReplacement(MagicMarkerRange, MagicMarkerText);
1248  }
1249  Context.addComment(RC);
1250}
1251
1252// Pin this vtable to this file.
1253ExternalSemaSource::~ExternalSemaSource() {}
1254
1255void ExternalSemaSource::ReadMethodPool(Selector Sel) { }
1256void ExternalSemaSource::updateOutOfDateSelector(Selector Sel) { }
1257
1258void ExternalSemaSource::ReadKnownNamespaces(
1259                           SmallVectorImpl<NamespaceDecl *> &Namespaces) {
1260}
1261
1262void ExternalSemaSource::ReadUndefinedButUsed(
1263    llvm::MapVector<NamedDecl *, SourceLocation> &Undefined) {}
1264
1265void ExternalSemaSource::ReadMismatchingDeleteExpressions(llvm::MapVector<
1266    FieldDecl *, llvm::SmallVector<std::pair<SourceLocation, bool>, 4>> &) {}
1267
1268void PrettyDeclStackTraceEntry::print(raw_ostream &OS) const {
1269  SourceLocation Loc = this->Loc;
1270  if (!Loc.isValid() && TheDecl) Loc = TheDecl->getLocation();
1271  if (Loc.isValid()) {
1272    Loc.print(OS, S.getSourceManager());
1273    OS << ": ";
1274  }
1275  OS << Message;
1276
1277  if (auto *ND = dyn_cast_or_null<NamedDecl>(TheDecl)) {
1278    OS << " '";
1279    ND->getNameForDiagnostic(OS, ND->getASTContext().getPrintingPolicy(), true);
1280    OS << "'";
1281  }
1282
1283  OS << '\n';
1284}
1285
1286/// \brief Figure out if an expression could be turned into a call.
1287///
1288/// Use this when trying to recover from an error where the programmer may have
1289/// written just the name of a function instead of actually calling it.
1290///
1291/// \param E - The expression to examine.
1292/// \param ZeroArgCallReturnTy - If the expression can be turned into a call
1293///  with no arguments, this parameter is set to the type returned by such a
1294///  call; otherwise, it is set to an empty QualType.
1295/// \param OverloadSet - If the expression is an overloaded function
1296///  name, this parameter is populated with the decls of the various overloads.
1297bool Sema::tryExprAsCall(Expr &E, QualType &ZeroArgCallReturnTy,
1298                         UnresolvedSetImpl &OverloadSet) {
1299  ZeroArgCallReturnTy = QualType();
1300  OverloadSet.clear();
1301
1302  const OverloadExpr *Overloads = nullptr;
1303  bool IsMemExpr = false;
1304  if (E.getType() == Context.OverloadTy) {
1305    OverloadExpr::FindResult FR = OverloadExpr::find(const_cast<Expr*>(&E));
1306
1307    // Ignore overloads that are pointer-to-member constants.
1308    if (FR.HasFormOfMemberPointer)
1309      return false;
1310
1311    Overloads = FR.Expression;
1312  } else if (E.getType() == Context.BoundMemberTy) {
1313    Overloads = dyn_cast<UnresolvedMemberExpr>(E.IgnoreParens());
1314    IsMemExpr = true;
1315  }
1316
1317  bool Ambiguous = false;
1318
1319  if (Overloads) {
1320    for (OverloadExpr::decls_iterator it = Overloads->decls_begin(),
1321         DeclsEnd = Overloads->decls_end(); it != DeclsEnd; ++it) {
1322      OverloadSet.addDecl(*it);
1323
1324      // Check whether the function is a non-template, non-member which takes no
1325      // arguments.
1326      if (IsMemExpr)
1327        continue;
1328      if (const FunctionDecl *OverloadDecl
1329            = dyn_cast<FunctionDecl>((*it)->getUnderlyingDecl())) {
1330        if (OverloadDecl->getMinRequiredArguments() == 0) {
1331          if (!ZeroArgCallReturnTy.isNull() && !Ambiguous) {
1332            ZeroArgCallReturnTy = QualType();
1333            Ambiguous = true;
1334          } else
1335            ZeroArgCallReturnTy = OverloadDecl->getReturnType();
1336        }
1337      }
1338    }
1339
1340    // If it's not a member, use better machinery to try to resolve the call
1341    if (!IsMemExpr)
1342      return !ZeroArgCallReturnTy.isNull();
1343  }
1344
1345  // Attempt to call the member with no arguments - this will correctly handle
1346  // member templates with defaults/deduction of template arguments, overloads
1347  // with default arguments, etc.
1348  if (IsMemExpr && !E.isTypeDependent()) {
1349    bool Suppress = getDiagnostics().getSuppressAllDiagnostics();
1350    getDiagnostics().setSuppressAllDiagnostics(true);
1351    ExprResult R = BuildCallToMemberFunction(nullptr, &E, SourceLocation(),
1352                                             None, SourceLocation());
1353    getDiagnostics().setSuppressAllDiagnostics(Suppress);
1354    if (R.isUsable()) {
1355      ZeroArgCallReturnTy = R.get()->getType();
1356      return true;
1357    }
1358    return false;
1359  }
1360
1361  if (const DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(E.IgnoreParens())) {
1362    if (const FunctionDecl *Fun = dyn_cast<FunctionDecl>(DeclRef->getDecl())) {
1363      if (Fun->getMinRequiredArguments() == 0)
1364        ZeroArgCallReturnTy = Fun->getReturnType();
1365      return true;
1366    }
1367  }
1368
1369  // We don't have an expression that's convenient to get a FunctionDecl from,
1370  // but we can at least check if the type is "function of 0 arguments".
1371  QualType ExprTy = E.getType();
1372  const FunctionType *FunTy = nullptr;
1373  QualType PointeeTy = ExprTy->getPointeeType();
1374  if (!PointeeTy.isNull())
1375    FunTy = PointeeTy->getAs<FunctionType>();
1376  if (!FunTy)
1377    FunTy = ExprTy->getAs<FunctionType>();
1378
1379  if (const FunctionProtoType *FPT =
1380      dyn_cast_or_null<FunctionProtoType>(FunTy)) {
1381    if (FPT->getNumParams() == 0)
1382      ZeroArgCallReturnTy = FunTy->getReturnType();
1383    return true;
1384  }
1385  return false;
1386}
1387
1388/// \brief Give notes for a set of overloads.
1389///
1390/// A companion to tryExprAsCall. In cases when the name that the programmer
1391/// wrote was an overloaded function, we may be able to make some guesses about
1392/// plausible overloads based on their return types; such guesses can be handed
1393/// off to this method to be emitted as notes.
1394///
1395/// \param Overloads - The overloads to note.
1396/// \param FinalNoteLoc - If we've suppressed printing some overloads due to
1397///  -fshow-overloads=best, this is the location to attach to the note about too
1398///  many candidates. Typically this will be the location of the original
1399///  ill-formed expression.
1400static void noteOverloads(Sema &S, const UnresolvedSetImpl &Overloads,
1401                          const SourceLocation FinalNoteLoc) {
1402  int ShownOverloads = 0;
1403  int SuppressedOverloads = 0;
1404  for (UnresolvedSetImpl::iterator It = Overloads.begin(),
1405       DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) {
1406    // FIXME: Magic number for max shown overloads stolen from
1407    // OverloadCandidateSet::NoteCandidates.
1408    if (ShownOverloads >= 4 && S.Diags.getShowOverloads() == Ovl_Best) {
1409      ++SuppressedOverloads;
1410      continue;
1411    }
1412
1413    NamedDecl *Fn = (*It)->getUnderlyingDecl();
1414    S.Diag(Fn->getLocation(), diag::note_possible_target_of_call);
1415    ++ShownOverloads;
1416  }
1417
1418  if (SuppressedOverloads)
1419    S.Diag(FinalNoteLoc, diag::note_ovl_too_many_candidates)
1420      << SuppressedOverloads;
1421}
1422
1423static void notePlausibleOverloads(Sema &S, SourceLocation Loc,
1424                                   const UnresolvedSetImpl &Overloads,
1425                                   bool (*IsPlausibleResult)(QualType)) {
1426  if (!IsPlausibleResult)
1427    return noteOverloads(S, Overloads, Loc);
1428
1429  UnresolvedSet<2> PlausibleOverloads;
1430  for (OverloadExpr::decls_iterator It = Overloads.begin(),
1431         DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) {
1432    const FunctionDecl *OverloadDecl = cast<FunctionDecl>(*It);
1433    QualType OverloadResultTy = OverloadDecl->getReturnType();
1434    if (IsPlausibleResult(OverloadResultTy))
1435      PlausibleOverloads.addDecl(It.getDecl());
1436  }
1437  noteOverloads(S, PlausibleOverloads, Loc);
1438}
1439
1440/// Determine whether the given expression can be called by just
1441/// putting parentheses after it.  Notably, expressions with unary
1442/// operators can't be because the unary operator will start parsing
1443/// outside the call.
1444static bool IsCallableWithAppend(Expr *E) {
1445  E = E->IgnoreImplicit();
1446  return (!isa<CStyleCastExpr>(E) &&
1447          !isa<UnaryOperator>(E) &&
1448          !isa<BinaryOperator>(E) &&
1449          !isa<CXXOperatorCallExpr>(E));
1450}
1451
1452bool Sema::tryToRecoverWithCall(ExprResult &E, const PartialDiagnostic &PD,
1453                                bool ForceComplain,
1454                                bool (*IsPlausibleResult)(QualType)) {
1455  SourceLocation Loc = E.get()->getExprLoc();
1456  SourceRange Range = E.get()->getSourceRange();
1457
1458  QualType ZeroArgCallTy;
1459  UnresolvedSet<4> Overloads;
1460  if (tryExprAsCall(*E.get(), ZeroArgCallTy, Overloads) &&
1461      !ZeroArgCallTy.isNull() &&
1462      (!IsPlausibleResult || IsPlausibleResult(ZeroArgCallTy))) {
1463    // At this point, we know E is potentially callable with 0
1464    // arguments and that it returns something of a reasonable type,
1465    // so we can emit a fixit and carry on pretending that E was
1466    // actually a CallExpr.
1467    SourceLocation ParenInsertionLoc = getLocForEndOfToken(Range.getEnd());
1468    Diag(Loc, PD)
1469      << /*zero-arg*/ 1 << Range
1470      << (IsCallableWithAppend(E.get())
1471          ? FixItHint::CreateInsertion(ParenInsertionLoc, "()")
1472          : FixItHint());
1473    notePlausibleOverloads(*this, Loc, Overloads, IsPlausibleResult);
1474
1475    // FIXME: Try this before emitting the fixit, and suppress diagnostics
1476    // while doing so.
1477    E = ActOnCallExpr(nullptr, E.get(), Range.getEnd(), None,
1478                      Range.getEnd().getLocWithOffset(1));
1479    return true;
1480  }
1481
1482  if (!ForceComplain) return false;
1483
1484  Diag(Loc, PD) << /*not zero-arg*/ 0 << Range;
1485  notePlausibleOverloads(*this, Loc, Overloads, IsPlausibleResult);
1486  E = ExprError();
1487  return true;
1488}
1489
1490IdentifierInfo *Sema::getSuperIdentifier() const {
1491  if (!Ident_super)
1492    Ident_super = &Context.Idents.get("super");
1493  return Ident_super;
1494}
1495
1496IdentifierInfo *Sema::getFloat128Identifier() const {
1497  if (!Ident___float128)
1498    Ident___float128 = &Context.Idents.get("__float128");
1499  return Ident___float128;
1500}
1501
1502void Sema::PushCapturedRegionScope(Scope *S, CapturedDecl *CD, RecordDecl *RD,
1503                                   CapturedRegionKind K) {
1504  CapturingScopeInfo *CSI = new CapturedRegionScopeInfo(
1505      getDiagnostics(), S, CD, RD, CD->getContextParam(), K,
1506      (getLangOpts().OpenMP && K == CR_OpenMP) ? getOpenMPNestingLevel() : 0);
1507  CSI->ReturnType = Context.VoidTy;
1508  FunctionScopes.push_back(CSI);
1509}
1510
1511CapturedRegionScopeInfo *Sema::getCurCapturedRegion() {
1512  if (FunctionScopes.empty())
1513    return nullptr;
1514
1515  return dyn_cast<CapturedRegionScopeInfo>(FunctionScopes.back());
1516}
1517
1518const llvm::MapVector<FieldDecl *, Sema::DeleteLocs> &
1519Sema::getMismatchingDeleteExpressions() const {
1520  return DeleteExprs;
1521}
1522