1//===- DeclBase.cpp - Declaration AST Node Implementation -----------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the Decl and DeclContext classes.
10//
11//===----------------------------------------------------------------------===//
12
13#include "clang/AST/DeclBase.h"
14#include "clang/AST/ASTContext.h"
15#include "clang/AST/ASTLambda.h"
16#include "clang/AST/ASTMutationListener.h"
17#include "clang/AST/Attr.h"
18#include "clang/AST/AttrIterator.h"
19#include "clang/AST/Decl.h"
20#include "clang/AST/DeclCXX.h"
21#include "clang/AST/DeclContextInternals.h"
22#include "clang/AST/DeclFriend.h"
23#include "clang/AST/DeclObjC.h"
24#include "clang/AST/DeclOpenMP.h"
25#include "clang/AST/DeclTemplate.h"
26#include "clang/AST/DependentDiagnostic.h"
27#include "clang/AST/ExternalASTSource.h"
28#include "clang/AST/Stmt.h"
29#include "clang/AST/Type.h"
30#include "clang/Basic/IdentifierTable.h"
31#include "clang/Basic/LLVM.h"
32#include "clang/Basic/LangOptions.h"
33#include "clang/Basic/ObjCRuntime.h"
34#include "clang/Basic/PartialDiagnostic.h"
35#include "clang/Basic/SourceLocation.h"
36#include "clang/Basic/TargetInfo.h"
37#include "llvm/ADT/ArrayRef.h"
38#include "llvm/ADT/PointerIntPair.h"
39#include "llvm/ADT/SmallVector.h"
40#include "llvm/ADT/StringRef.h"
41#include "llvm/Support/Casting.h"
42#include "llvm/Support/ErrorHandling.h"
43#include "llvm/Support/MathExtras.h"
44#include "llvm/Support/VersionTuple.h"
45#include "llvm/Support/raw_ostream.h"
46#include <algorithm>
47#include <cassert>
48#include <cstddef>
49#include <string>
50#include <tuple>
51#include <utility>
52
53using namespace clang;
54
55//===----------------------------------------------------------------------===//
56//  Statistics
57//===----------------------------------------------------------------------===//
58
59#define DECL(DERIVED, BASE) static int n##DERIVED##s = 0;
60#define ABSTRACT_DECL(DECL)
61#include "clang/AST/DeclNodes.inc"
62
63void Decl::updateOutOfDate(IdentifierInfo &II) const {
64  getASTContext().getExternalSource()->updateOutOfDateIdentifier(II);
65}
66
67#define DECL(DERIVED, BASE)                                                    \
68  static_assert(alignof(Decl) >= alignof(DERIVED##Decl),                       \
69                "Alignment sufficient after objects prepended to " #DERIVED);
70#define ABSTRACT_DECL(DECL)
71#include "clang/AST/DeclNodes.inc"
72
73void *Decl::operator new(std::size_t Size, const ASTContext &Context,
74                         unsigned ID, std::size_t Extra) {
75  // Allocate an extra 8 bytes worth of storage, which ensures that the
76  // resulting pointer will still be 8-byte aligned.
77  static_assert(sizeof(unsigned) * 2 >= alignof(Decl),
78                "Decl won't be misaligned");
79  void *Start = Context.Allocate(Size + Extra + 8);
80  void *Result = (char*)Start + 8;
81
82  unsigned *PrefixPtr = (unsigned *)Result - 2;
83
84  // Zero out the first 4 bytes; this is used to store the owning module ID.
85  PrefixPtr[0] = 0;
86
87  // Store the global declaration ID in the second 4 bytes.
88  PrefixPtr[1] = ID;
89
90  return Result;
91}
92
93void *Decl::operator new(std::size_t Size, const ASTContext &Ctx,
94                         DeclContext *Parent, std::size_t Extra) {
95  assert(!Parent || &Parent->getParentASTContext() == &Ctx);
96  // With local visibility enabled, we track the owning module even for local
97  // declarations. We create the TU decl early and may not yet know what the
98  // LangOpts are, so conservatively allocate the storage.
99  if (Ctx.getLangOpts().trackLocalOwningModule() || !Parent) {
100    // Ensure required alignment of the resulting object by adding extra
101    // padding at the start if required.
102    size_t ExtraAlign =
103        llvm::offsetToAlignment(sizeof(Module *), llvm::Align(alignof(Decl)));
104    auto *Buffer = reinterpret_cast<char *>(
105        ::operator new(ExtraAlign + sizeof(Module *) + Size + Extra, Ctx));
106    Buffer += ExtraAlign;
107    auto *ParentModule =
108        Parent ? cast<Decl>(Parent)->getOwningModule() : nullptr;
109    return new (Buffer) Module*(ParentModule) + 1;
110  }
111  return ::operator new(Size + Extra, Ctx);
112}
113
114Module *Decl::getOwningModuleSlow() const {
115  assert(isFromASTFile() && "Not from AST file?");
116  return getASTContext().getExternalSource()->getModule(getOwningModuleID());
117}
118
119bool Decl::hasLocalOwningModuleStorage() const {
120  return getASTContext().getLangOpts().trackLocalOwningModule();
121}
122
123const char *Decl::getDeclKindName() const {
124  switch (DeclKind) {
125  default: llvm_unreachable("Declaration not in DeclNodes.inc!");
126#define DECL(DERIVED, BASE) case DERIVED: return #DERIVED;
127#define ABSTRACT_DECL(DECL)
128#include "clang/AST/DeclNodes.inc"
129  }
130}
131
132void Decl::setInvalidDecl(bool Invalid) {
133  InvalidDecl = Invalid;
134  assert(!isa<TagDecl>(this) || !cast<TagDecl>(this)->isCompleteDefinition());
135  if (!Invalid) {
136    return;
137  }
138
139  if (!isa<ParmVarDecl>(this)) {
140    // Defensive maneuver for ill-formed code: we're likely not to make it to
141    // a point where we set the access specifier, so default it to "public"
142    // to avoid triggering asserts elsewhere in the front end.
143    setAccess(AS_public);
144  }
145
146  // Marking a DecompositionDecl as invalid implies all the child BindingDecl's
147  // are invalid too.
148  if (auto *DD = dyn_cast<DecompositionDecl>(this)) {
149    for (auto *Binding : DD->bindings()) {
150      Binding->setInvalidDecl();
151    }
152  }
153}
154
155const char *DeclContext::getDeclKindName() const {
156  switch (getDeclKind()) {
157#define DECL(DERIVED, BASE) case Decl::DERIVED: return #DERIVED;
158#define ABSTRACT_DECL(DECL)
159#include "clang/AST/DeclNodes.inc"
160  }
161  llvm_unreachable("Declaration context not in DeclNodes.inc!");
162}
163
164bool Decl::StatisticsEnabled = false;
165void Decl::EnableStatistics() {
166  StatisticsEnabled = true;
167}
168
169void Decl::PrintStats() {
170  llvm::errs() << "\n*** Decl Stats:\n";
171
172  int totalDecls = 0;
173#define DECL(DERIVED, BASE) totalDecls += n##DERIVED##s;
174#define ABSTRACT_DECL(DECL)
175#include "clang/AST/DeclNodes.inc"
176  llvm::errs() << "  " << totalDecls << " decls total.\n";
177
178  int totalBytes = 0;
179#define DECL(DERIVED, BASE)                                             \
180  if (n##DERIVED##s > 0) {                                              \
181    totalBytes += (int)(n##DERIVED##s * sizeof(DERIVED##Decl));         \
182    llvm::errs() << "    " << n##DERIVED##s << " " #DERIVED " decls, "  \
183                 << sizeof(DERIVED##Decl) << " each ("                  \
184                 << n##DERIVED##s * sizeof(DERIVED##Decl)               \
185                 << " bytes)\n";                                        \
186  }
187#define ABSTRACT_DECL(DECL)
188#include "clang/AST/DeclNodes.inc"
189
190  llvm::errs() << "Total bytes = " << totalBytes << "\n";
191}
192
193void Decl::add(Kind k) {
194  switch (k) {
195#define DECL(DERIVED, BASE) case DERIVED: ++n##DERIVED##s; break;
196#define ABSTRACT_DECL(DECL)
197#include "clang/AST/DeclNodes.inc"
198  }
199}
200
201bool Decl::isTemplateParameterPack() const {
202  if (const auto *TTP = dyn_cast<TemplateTypeParmDecl>(this))
203    return TTP->isParameterPack();
204  if (const auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(this))
205    return NTTP->isParameterPack();
206  if (const auto *TTP = dyn_cast<TemplateTemplateParmDecl>(this))
207    return TTP->isParameterPack();
208  return false;
209}
210
211bool Decl::isParameterPack() const {
212  if (const auto *Var = dyn_cast<VarDecl>(this))
213    return Var->isParameterPack();
214
215  return isTemplateParameterPack();
216}
217
218FunctionDecl *Decl::getAsFunction() {
219  if (auto *FD = dyn_cast<FunctionDecl>(this))
220    return FD;
221  if (const auto *FTD = dyn_cast<FunctionTemplateDecl>(this))
222    return FTD->getTemplatedDecl();
223  return nullptr;
224}
225
226bool Decl::isTemplateDecl() const {
227  return isa<TemplateDecl>(this);
228}
229
230TemplateDecl *Decl::getDescribedTemplate() const {
231  if (auto *FD = dyn_cast<FunctionDecl>(this))
232    return FD->getDescribedFunctionTemplate();
233  else if (auto *RD = dyn_cast<CXXRecordDecl>(this))
234    return RD->getDescribedClassTemplate();
235  else if (auto *VD = dyn_cast<VarDecl>(this))
236    return VD->getDescribedVarTemplate();
237  else if (auto *AD = dyn_cast<TypeAliasDecl>(this))
238    return AD->getDescribedAliasTemplate();
239
240  return nullptr;
241}
242
243const TemplateParameterList *Decl::getDescribedTemplateParams() const {
244  if (auto *TD = getDescribedTemplate())
245    return TD->getTemplateParameters();
246  if (auto *CTPSD = dyn_cast<ClassTemplatePartialSpecializationDecl>(this))
247    return CTPSD->getTemplateParameters();
248  if (auto *VTPSD = dyn_cast<VarTemplatePartialSpecializationDecl>(this))
249    return VTPSD->getTemplateParameters();
250  return nullptr;
251}
252
253bool Decl::isTemplated() const {
254  // A declaration is templated if it is a template or a template pattern, or
255  // is within (lexcially for a friend, semantically otherwise) a dependent
256  // context.
257  // FIXME: Should local extern declarations be treated like friends?
258  if (auto *AsDC = dyn_cast<DeclContext>(this))
259    return AsDC->isDependentContext();
260  auto *DC = getFriendObjectKind() ? getLexicalDeclContext() : getDeclContext();
261  return DC->isDependentContext() || isTemplateDecl() ||
262         getDescribedTemplateParams();
263}
264
265unsigned Decl::getTemplateDepth() const {
266  if (auto *DC = dyn_cast<DeclContext>(this))
267    if (DC->isFileContext())
268      return 0;
269
270  if (auto *TPL = getDescribedTemplateParams())
271    return TPL->getDepth() + 1;
272
273  // If this is a dependent lambda, there might be an enclosing variable
274  // template. In this case, the next step is not the parent DeclContext (or
275  // even a DeclContext at all).
276  auto *RD = dyn_cast<CXXRecordDecl>(this);
277  if (RD && RD->isDependentLambda())
278    if (Decl *Context = RD->getLambdaContextDecl())
279      return Context->getTemplateDepth();
280
281  const DeclContext *DC =
282      getFriendObjectKind() ? getLexicalDeclContext() : getDeclContext();
283  return cast<Decl>(DC)->getTemplateDepth();
284}
285
286const DeclContext *Decl::getParentFunctionOrMethod() const {
287  for (const DeclContext *DC = getDeclContext();
288       DC && !DC->isTranslationUnit() && !DC->isNamespace();
289       DC = DC->getParent())
290    if (DC->isFunctionOrMethod())
291      return DC;
292
293  return nullptr;
294}
295
296//===----------------------------------------------------------------------===//
297// PrettyStackTraceDecl Implementation
298//===----------------------------------------------------------------------===//
299
300void PrettyStackTraceDecl::print(raw_ostream &OS) const {
301  SourceLocation TheLoc = Loc;
302  if (TheLoc.isInvalid() && TheDecl)
303    TheLoc = TheDecl->getLocation();
304
305  if (TheLoc.isValid()) {
306    TheLoc.print(OS, SM);
307    OS << ": ";
308  }
309
310  OS << Message;
311
312  if (const auto *DN = dyn_cast_or_null<NamedDecl>(TheDecl)) {
313    OS << " '";
314    DN->printQualifiedName(OS);
315    OS << '\'';
316  }
317  OS << '\n';
318}
319
320//===----------------------------------------------------------------------===//
321// Decl Implementation
322//===----------------------------------------------------------------------===//
323
324// Out-of-line virtual method providing a home for Decl.
325Decl::~Decl() = default;
326
327void Decl::setDeclContext(DeclContext *DC) {
328  DeclCtx = DC;
329}
330
331void Decl::setLexicalDeclContext(DeclContext *DC) {
332  if (DC == getLexicalDeclContext())
333    return;
334
335  if (isInSemaDC()) {
336    setDeclContextsImpl(getDeclContext(), DC, getASTContext());
337  } else {
338    getMultipleDC()->LexicalDC = DC;
339  }
340
341  // FIXME: We shouldn't be changing the lexical context of declarations
342  // imported from AST files.
343  if (!isFromASTFile()) {
344    setModuleOwnershipKind(getModuleOwnershipKindForChildOf(DC));
345    if (hasOwningModule())
346      setLocalOwningModule(cast<Decl>(DC)->getOwningModule());
347  }
348
349  assert(
350      (getModuleOwnershipKind() != ModuleOwnershipKind::VisibleWhenImported ||
351       getOwningModule()) &&
352      "hidden declaration has no owning module");
353}
354
355void Decl::setDeclContextsImpl(DeclContext *SemaDC, DeclContext *LexicalDC,
356                               ASTContext &Ctx) {
357  if (SemaDC == LexicalDC) {
358    DeclCtx = SemaDC;
359  } else {
360    auto *MDC = new (Ctx) Decl::MultipleDC();
361    MDC->SemanticDC = SemaDC;
362    MDC->LexicalDC = LexicalDC;
363    DeclCtx = MDC;
364  }
365}
366
367bool Decl::isInLocalScopeForInstantiation() const {
368  const DeclContext *LDC = getLexicalDeclContext();
369  if (!LDC->isDependentContext())
370    return false;
371  while (true) {
372    if (LDC->isFunctionOrMethod())
373      return true;
374    if (!isa<TagDecl>(LDC))
375      return false;
376    if (const auto *CRD = dyn_cast<CXXRecordDecl>(LDC))
377      if (CRD->isLambda())
378        return true;
379    LDC = LDC->getLexicalParent();
380  }
381  return false;
382}
383
384bool Decl::isInAnonymousNamespace() const {
385  for (const DeclContext *DC = getDeclContext(); DC; DC = DC->getParent()) {
386    if (const auto *ND = dyn_cast<NamespaceDecl>(DC))
387      if (ND->isAnonymousNamespace())
388        return true;
389  }
390
391  return false;
392}
393
394bool Decl::isInStdNamespace() const {
395  const DeclContext *DC = getDeclContext();
396  return DC && DC->isStdNamespace();
397}
398
399TranslationUnitDecl *Decl::getTranslationUnitDecl() {
400  if (auto *TUD = dyn_cast<TranslationUnitDecl>(this))
401    return TUD;
402
403  DeclContext *DC = getDeclContext();
404  assert(DC && "This decl is not contained in a translation unit!");
405
406  while (!DC->isTranslationUnit()) {
407    DC = DC->getParent();
408    assert(DC && "This decl is not contained in a translation unit!");
409  }
410
411  return cast<TranslationUnitDecl>(DC);
412}
413
414ASTContext &Decl::getASTContext() const {
415  return getTranslationUnitDecl()->getASTContext();
416}
417
418/// Helper to get the language options from the ASTContext.
419/// Defined out of line to avoid depending on ASTContext.h.
420const LangOptions &Decl::getLangOpts() const {
421  return getASTContext().getLangOpts();
422}
423
424ASTMutationListener *Decl::getASTMutationListener() const {
425  return getASTContext().getASTMutationListener();
426}
427
428unsigned Decl::getMaxAlignment() const {
429  if (!hasAttrs())
430    return 0;
431
432  unsigned Align = 0;
433  const AttrVec &V = getAttrs();
434  ASTContext &Ctx = getASTContext();
435  specific_attr_iterator<AlignedAttr> I(V.begin()), E(V.end());
436  for (; I != E; ++I) {
437    if (!I->isAlignmentErrorDependent())
438      Align = std::max(Align, I->getAlignment(Ctx));
439  }
440  return Align;
441}
442
443bool Decl::isUsed(bool CheckUsedAttr) const {
444  const Decl *CanonD = getCanonicalDecl();
445  if (CanonD->Used)
446    return true;
447
448  // Check for used attribute.
449  // Ask the most recent decl, since attributes accumulate in the redecl chain.
450  if (CheckUsedAttr && getMostRecentDecl()->hasAttr<UsedAttr>())
451    return true;
452
453  // The information may have not been deserialized yet. Force deserialization
454  // to complete the needed information.
455  return getMostRecentDecl()->getCanonicalDecl()->Used;
456}
457
458void Decl::markUsed(ASTContext &C) {
459  if (isUsed(false))
460    return;
461
462  if (C.getASTMutationListener())
463    C.getASTMutationListener()->DeclarationMarkedUsed(this);
464
465  setIsUsed();
466}
467
468bool Decl::isReferenced() const {
469  if (Referenced)
470    return true;
471
472  // Check redeclarations.
473  for (const auto *I : redecls())
474    if (I->Referenced)
475      return true;
476
477  return false;
478}
479
480ExternalSourceSymbolAttr *Decl::getExternalSourceSymbolAttr() const {
481  const Decl *Definition = nullptr;
482  if (auto *ID = dyn_cast<ObjCInterfaceDecl>(this)) {
483    Definition = ID->getDefinition();
484  } else if (auto *PD = dyn_cast<ObjCProtocolDecl>(this)) {
485    Definition = PD->getDefinition();
486  } else if (auto *TD = dyn_cast<TagDecl>(this)) {
487    Definition = TD->getDefinition();
488  }
489  if (!Definition)
490    Definition = this;
491
492  if (auto *attr = Definition->getAttr<ExternalSourceSymbolAttr>())
493    return attr;
494  if (auto *dcd = dyn_cast<Decl>(getDeclContext())) {
495    return dcd->getAttr<ExternalSourceSymbolAttr>();
496  }
497
498  return nullptr;
499}
500
501bool Decl::hasDefiningAttr() const {
502  return hasAttr<AliasAttr>() || hasAttr<IFuncAttr>() ||
503         hasAttr<LoaderUninitializedAttr>();
504}
505
506const Attr *Decl::getDefiningAttr() const {
507  if (auto *AA = getAttr<AliasAttr>())
508    return AA;
509  if (auto *IFA = getAttr<IFuncAttr>())
510    return IFA;
511  if (auto *NZA = getAttr<LoaderUninitializedAttr>())
512    return NZA;
513  return nullptr;
514}
515
516static StringRef getRealizedPlatform(const AvailabilityAttr *A,
517                                     const ASTContext &Context) {
518  // Check if this is an App Extension "platform", and if so chop off
519  // the suffix for matching with the actual platform.
520  StringRef RealizedPlatform = A->getPlatform()->getName();
521  if (!Context.getLangOpts().AppExt)
522    return RealizedPlatform;
523  size_t suffix = RealizedPlatform.rfind("_app_extension");
524  if (suffix != StringRef::npos)
525    return RealizedPlatform.slice(0, suffix);
526  return RealizedPlatform;
527}
528
529/// Determine the availability of the given declaration based on
530/// the target platform.
531///
532/// When it returns an availability result other than \c AR_Available,
533/// if the \p Message parameter is non-NULL, it will be set to a
534/// string describing why the entity is unavailable.
535///
536/// FIXME: Make these strings localizable, since they end up in
537/// diagnostics.
538static AvailabilityResult CheckAvailability(ASTContext &Context,
539                                            const AvailabilityAttr *A,
540                                            std::string *Message,
541                                            VersionTuple EnclosingVersion) {
542  if (EnclosingVersion.empty())
543    EnclosingVersion = Context.getTargetInfo().getPlatformMinVersion();
544
545  if (EnclosingVersion.empty())
546    return AR_Available;
547
548  StringRef ActualPlatform = A->getPlatform()->getName();
549  StringRef TargetPlatform = Context.getTargetInfo().getPlatformName();
550
551  // Match the platform name.
552  if (getRealizedPlatform(A, Context) != TargetPlatform)
553    return AR_Available;
554
555  StringRef PrettyPlatformName
556    = AvailabilityAttr::getPrettyPlatformName(ActualPlatform);
557
558  if (PrettyPlatformName.empty())
559    PrettyPlatformName = ActualPlatform;
560
561  std::string HintMessage;
562  if (!A->getMessage().empty()) {
563    HintMessage = " - ";
564    HintMessage += A->getMessage();
565  }
566
567  // Make sure that this declaration has not been marked 'unavailable'.
568  if (A->getUnavailable()) {
569    if (Message) {
570      Message->clear();
571      llvm::raw_string_ostream Out(*Message);
572      Out << "not available on " << PrettyPlatformName
573          << HintMessage;
574    }
575
576    return AR_Unavailable;
577  }
578
579  // Make sure that this declaration has already been introduced.
580  if (!A->getIntroduced().empty() &&
581      EnclosingVersion < A->getIntroduced()) {
582    if (Message) {
583      Message->clear();
584      llvm::raw_string_ostream Out(*Message);
585      VersionTuple VTI(A->getIntroduced());
586      Out << "introduced in " << PrettyPlatformName << ' '
587          << VTI << HintMessage;
588    }
589
590    return A->getStrict() ? AR_Unavailable : AR_NotYetIntroduced;
591  }
592
593  // Make sure that this declaration hasn't been obsoleted.
594  if (!A->getObsoleted().empty() && EnclosingVersion >= A->getObsoleted()) {
595    if (Message) {
596      Message->clear();
597      llvm::raw_string_ostream Out(*Message);
598      VersionTuple VTO(A->getObsoleted());
599      Out << "obsoleted in " << PrettyPlatformName << ' '
600          << VTO << HintMessage;
601    }
602
603    return AR_Unavailable;
604  }
605
606  // Make sure that this declaration hasn't been deprecated.
607  if (!A->getDeprecated().empty() && EnclosingVersion >= A->getDeprecated()) {
608    if (Message) {
609      Message->clear();
610      llvm::raw_string_ostream Out(*Message);
611      VersionTuple VTD(A->getDeprecated());
612      Out << "first deprecated in " << PrettyPlatformName << ' '
613          << VTD << HintMessage;
614    }
615
616    return AR_Deprecated;
617  }
618
619  return AR_Available;
620}
621
622AvailabilityResult Decl::getAvailability(std::string *Message,
623                                         VersionTuple EnclosingVersion,
624                                         StringRef *RealizedPlatform) const {
625  if (auto *FTD = dyn_cast<FunctionTemplateDecl>(this))
626    return FTD->getTemplatedDecl()->getAvailability(Message, EnclosingVersion,
627                                                    RealizedPlatform);
628
629  AvailabilityResult Result = AR_Available;
630  std::string ResultMessage;
631
632  for (const auto *A : attrs()) {
633    if (const auto *Deprecated = dyn_cast<DeprecatedAttr>(A)) {
634      if (Result >= AR_Deprecated)
635        continue;
636
637      if (Message)
638        ResultMessage = std::string(Deprecated->getMessage());
639
640      Result = AR_Deprecated;
641      continue;
642    }
643
644    if (const auto *Unavailable = dyn_cast<UnavailableAttr>(A)) {
645      if (Message)
646        *Message = std::string(Unavailable->getMessage());
647      return AR_Unavailable;
648    }
649
650    if (const auto *Availability = dyn_cast<AvailabilityAttr>(A)) {
651      AvailabilityResult AR = CheckAvailability(getASTContext(), Availability,
652                                                Message, EnclosingVersion);
653
654      if (AR == AR_Unavailable) {
655        if (RealizedPlatform)
656          *RealizedPlatform = Availability->getPlatform()->getName();
657        return AR_Unavailable;
658      }
659
660      if (AR > Result) {
661        Result = AR;
662        if (Message)
663          ResultMessage.swap(*Message);
664      }
665      continue;
666    }
667  }
668
669  if (Message)
670    Message->swap(ResultMessage);
671  return Result;
672}
673
674VersionTuple Decl::getVersionIntroduced() const {
675  const ASTContext &Context = getASTContext();
676  StringRef TargetPlatform = Context.getTargetInfo().getPlatformName();
677  for (const auto *A : attrs()) {
678    if (const auto *Availability = dyn_cast<AvailabilityAttr>(A)) {
679      if (getRealizedPlatform(Availability, Context) != TargetPlatform)
680        continue;
681      if (!Availability->getIntroduced().empty())
682        return Availability->getIntroduced();
683    }
684  }
685  return {};
686}
687
688bool Decl::canBeWeakImported(bool &IsDefinition) const {
689  IsDefinition = false;
690
691  // Variables, if they aren't definitions.
692  if (const auto *Var = dyn_cast<VarDecl>(this)) {
693    if (Var->isThisDeclarationADefinition()) {
694      IsDefinition = true;
695      return false;
696    }
697    return true;
698
699  // Functions, if they aren't definitions.
700  } else if (const auto *FD = dyn_cast<FunctionDecl>(this)) {
701    if (FD->hasBody()) {
702      IsDefinition = true;
703      return false;
704    }
705    return true;
706
707  // Objective-C classes, if this is the non-fragile runtime.
708  } else if (isa<ObjCInterfaceDecl>(this) &&
709             getASTContext().getLangOpts().ObjCRuntime.hasWeakClassImport()) {
710    return true;
711
712  // Nothing else.
713  } else {
714    return false;
715  }
716}
717
718bool Decl::isWeakImported() const {
719  bool IsDefinition;
720  if (!canBeWeakImported(IsDefinition))
721    return false;
722
723  for (const auto *A : attrs()) {
724    if (isa<WeakImportAttr>(A))
725      return true;
726
727    if (const auto *Availability = dyn_cast<AvailabilityAttr>(A)) {
728      if (CheckAvailability(getASTContext(), Availability, nullptr,
729                            VersionTuple()) == AR_NotYetIntroduced)
730        return true;
731    }
732  }
733
734  return false;
735}
736
737unsigned Decl::getIdentifierNamespaceForKind(Kind DeclKind) {
738  switch (DeclKind) {
739    case Function:
740    case CXXDeductionGuide:
741    case CXXMethod:
742    case CXXConstructor:
743    case ConstructorUsingShadow:
744    case CXXDestructor:
745    case CXXConversion:
746    case EnumConstant:
747    case Var:
748    case ImplicitParam:
749    case ParmVar:
750    case ObjCMethod:
751    case ObjCProperty:
752    case MSProperty:
753      return IDNS_Ordinary;
754    case Label:
755      return IDNS_Label;
756    case IndirectField:
757      return IDNS_Ordinary | IDNS_Member;
758
759    case Binding:
760    case NonTypeTemplateParm:
761    case VarTemplate:
762    case Concept:
763      // These (C++-only) declarations are found by redeclaration lookup for
764      // tag types, so we include them in the tag namespace.
765      return IDNS_Ordinary | IDNS_Tag;
766
767    case ObjCCompatibleAlias:
768    case ObjCInterface:
769      return IDNS_Ordinary | IDNS_Type;
770
771    case Typedef:
772    case TypeAlias:
773    case TemplateTypeParm:
774    case ObjCTypeParam:
775      return IDNS_Ordinary | IDNS_Type;
776
777    case UnresolvedUsingTypename:
778      return IDNS_Ordinary | IDNS_Type | IDNS_Using;
779
780    case UsingShadow:
781      return 0; // we'll actually overwrite this later
782
783    case UnresolvedUsingValue:
784      return IDNS_Ordinary | IDNS_Using;
785
786    case Using:
787    case UsingPack:
788      return IDNS_Using;
789
790    case ObjCProtocol:
791      return IDNS_ObjCProtocol;
792
793    case Field:
794    case ObjCAtDefsField:
795    case ObjCIvar:
796      return IDNS_Member;
797
798    case Record:
799    case CXXRecord:
800    case Enum:
801      return IDNS_Tag | IDNS_Type;
802
803    case Namespace:
804    case NamespaceAlias:
805      return IDNS_Namespace;
806
807    case FunctionTemplate:
808      return IDNS_Ordinary;
809
810    case ClassTemplate:
811    case TemplateTemplateParm:
812    case TypeAliasTemplate:
813      return IDNS_Ordinary | IDNS_Tag | IDNS_Type;
814
815    case OMPDeclareReduction:
816      return IDNS_OMPReduction;
817
818    case OMPDeclareMapper:
819      return IDNS_OMPMapper;
820
821    // Never have names.
822    case Friend:
823    case FriendTemplate:
824    case AccessSpec:
825    case LinkageSpec:
826    case Export:
827    case FileScopeAsm:
828    case StaticAssert:
829    case ObjCPropertyImpl:
830    case PragmaComment:
831    case PragmaDetectMismatch:
832    case Block:
833    case Captured:
834    case TranslationUnit:
835    case ExternCContext:
836    case Decomposition:
837    case MSGuid:
838
839    case UsingDirective:
840    case BuiltinTemplate:
841    case ClassTemplateSpecialization:
842    case ClassTemplatePartialSpecialization:
843    case ClassScopeFunctionSpecialization:
844    case VarTemplateSpecialization:
845    case VarTemplatePartialSpecialization:
846    case ObjCImplementation:
847    case ObjCCategory:
848    case ObjCCategoryImpl:
849    case Import:
850    case OMPThreadPrivate:
851    case OMPAllocate:
852    case OMPRequires:
853    case OMPCapturedExpr:
854    case Empty:
855    case LifetimeExtendedTemporary:
856    case RequiresExprBody:
857      // Never looked up by name.
858      return 0;
859  }
860
861  llvm_unreachable("Invalid DeclKind!");
862}
863
864void Decl::setAttrsImpl(const AttrVec &attrs, ASTContext &Ctx) {
865  assert(!HasAttrs && "Decl already contains attrs.");
866
867  AttrVec &AttrBlank = Ctx.getDeclAttrs(this);
868  assert(AttrBlank.empty() && "HasAttrs was wrong?");
869
870  AttrBlank = attrs;
871  HasAttrs = true;
872}
873
874void Decl::dropAttrs() {
875  if (!HasAttrs) return;
876
877  HasAttrs = false;
878  getASTContext().eraseDeclAttrs(this);
879}
880
881void Decl::addAttr(Attr *A) {
882  if (!hasAttrs()) {
883    setAttrs(AttrVec(1, A));
884    return;
885  }
886
887  AttrVec &Attrs = getAttrs();
888  if (!A->isInherited()) {
889    Attrs.push_back(A);
890    return;
891  }
892
893  // Attribute inheritance is processed after attribute parsing. To keep the
894  // order as in the source code, add inherited attributes before non-inherited
895  // ones.
896  auto I = Attrs.begin(), E = Attrs.end();
897  for (; I != E; ++I) {
898    if (!(*I)->isInherited())
899      break;
900  }
901  Attrs.insert(I, A);
902}
903
904const AttrVec &Decl::getAttrs() const {
905  assert(HasAttrs && "No attrs to get!");
906  return getASTContext().getDeclAttrs(this);
907}
908
909Decl *Decl::castFromDeclContext (const DeclContext *D) {
910  Decl::Kind DK = D->getDeclKind();
911  switch(DK) {
912#define DECL(NAME, BASE)
913#define DECL_CONTEXT(NAME) \
914    case Decl::NAME:       \
915      return static_cast<NAME##Decl *>(const_cast<DeclContext *>(D));
916#define DECL_CONTEXT_BASE(NAME)
917#include "clang/AST/DeclNodes.inc"
918    default:
919#define DECL(NAME, BASE)
920#define DECL_CONTEXT_BASE(NAME)                  \
921      if (DK >= first##NAME && DK <= last##NAME) \
922        return static_cast<NAME##Decl *>(const_cast<DeclContext *>(D));
923#include "clang/AST/DeclNodes.inc"
924      llvm_unreachable("a decl that inherits DeclContext isn't handled");
925  }
926}
927
928DeclContext *Decl::castToDeclContext(const Decl *D) {
929  Decl::Kind DK = D->getKind();
930  switch(DK) {
931#define DECL(NAME, BASE)
932#define DECL_CONTEXT(NAME) \
933    case Decl::NAME:       \
934      return static_cast<NAME##Decl *>(const_cast<Decl *>(D));
935#define DECL_CONTEXT_BASE(NAME)
936#include "clang/AST/DeclNodes.inc"
937    default:
938#define DECL(NAME, BASE)
939#define DECL_CONTEXT_BASE(NAME)                                   \
940      if (DK >= first##NAME && DK <= last##NAME)                  \
941        return static_cast<NAME##Decl *>(const_cast<Decl *>(D));
942#include "clang/AST/DeclNodes.inc"
943      llvm_unreachable("a decl that inherits DeclContext isn't handled");
944  }
945}
946
947SourceLocation Decl::getBodyRBrace() const {
948  // Special handling of FunctionDecl to avoid de-serializing the body from PCH.
949  // FunctionDecl stores EndRangeLoc for this purpose.
950  if (const auto *FD = dyn_cast<FunctionDecl>(this)) {
951    const FunctionDecl *Definition;
952    if (FD->hasBody(Definition))
953      return Definition->getSourceRange().getEnd();
954    return {};
955  }
956
957  if (Stmt *Body = getBody())
958    return Body->getSourceRange().getEnd();
959
960  return {};
961}
962
963bool Decl::AccessDeclContextSanity() const {
964#ifndef NDEBUG
965  // Suppress this check if any of the following hold:
966  // 1. this is the translation unit (and thus has no parent)
967  // 2. this is a template parameter (and thus doesn't belong to its context)
968  // 3. this is a non-type template parameter
969  // 4. the context is not a record
970  // 5. it's invalid
971  // 6. it's a C++0x static_assert.
972  // 7. it's a block literal declaration
973  if (isa<TranslationUnitDecl>(this) ||
974      isa<TemplateTypeParmDecl>(this) ||
975      isa<NonTypeTemplateParmDecl>(this) ||
976      !getDeclContext() ||
977      !isa<CXXRecordDecl>(getDeclContext()) ||
978      isInvalidDecl() ||
979      isa<StaticAssertDecl>(this) ||
980      isa<BlockDecl>(this) ||
981      // FIXME: a ParmVarDecl can have ClassTemplateSpecialization
982      // as DeclContext (?).
983      isa<ParmVarDecl>(this) ||
984      // FIXME: a ClassTemplateSpecialization or CXXRecordDecl can have
985      // AS_none as access specifier.
986      isa<CXXRecordDecl>(this) ||
987      isa<ClassScopeFunctionSpecializationDecl>(this))
988    return true;
989
990  assert(Access != AS_none &&
991         "Access specifier is AS_none inside a record decl");
992#endif
993  return true;
994}
995
996static Decl::Kind getKind(const Decl *D) { return D->getKind(); }
997static Decl::Kind getKind(const DeclContext *DC) { return DC->getDeclKind(); }
998
999int64_t Decl::getID() const {
1000  return getASTContext().getAllocator().identifyKnownAlignedObject<Decl>(this);
1001}
1002
1003const FunctionType *Decl::getFunctionType(bool BlocksToo) const {
1004  QualType Ty;
1005  if (const auto *D = dyn_cast<ValueDecl>(this))
1006    Ty = D->getType();
1007  else if (const auto *D = dyn_cast<TypedefNameDecl>(this))
1008    Ty = D->getUnderlyingType();
1009  else
1010    return nullptr;
1011
1012  if (Ty->isFunctionPointerType())
1013    Ty = Ty->castAs<PointerType>()->getPointeeType();
1014  else if (Ty->isFunctionReferenceType())
1015    Ty = Ty->castAs<ReferenceType>()->getPointeeType();
1016  else if (BlocksToo && Ty->isBlockPointerType())
1017    Ty = Ty->castAs<BlockPointerType>()->getPointeeType();
1018
1019  return Ty->getAs<FunctionType>();
1020}
1021
1022/// Starting at a given context (a Decl or DeclContext), look for a
1023/// code context that is not a closure (a lambda, block, etc.).
1024template <class T> static Decl *getNonClosureContext(T *D) {
1025  if (getKind(D) == Decl::CXXMethod) {
1026    auto *MD = cast<CXXMethodDecl>(D);
1027    if (MD->getOverloadedOperator() == OO_Call &&
1028        MD->getParent()->isLambda())
1029      return getNonClosureContext(MD->getParent()->getParent());
1030    return MD;
1031  } else if (auto *FD = dyn_cast<FunctionDecl>(D))
1032    return FD;
1033  else if (auto *MD = dyn_cast<ObjCMethodDecl>(D))
1034    return MD;
1035  else if (auto *BD = dyn_cast<BlockDecl>(D))
1036    return getNonClosureContext(BD->getParent());
1037  else if (auto *CD = dyn_cast<CapturedDecl>(D))
1038    return getNonClosureContext(CD->getParent());
1039  else
1040    return nullptr;
1041}
1042
1043Decl *Decl::getNonClosureContext() {
1044  return ::getNonClosureContext(this);
1045}
1046
1047Decl *DeclContext::getNonClosureAncestor() {
1048  return ::getNonClosureContext(this);
1049}
1050
1051//===----------------------------------------------------------------------===//
1052// DeclContext Implementation
1053//===----------------------------------------------------------------------===//
1054
1055DeclContext::DeclContext(Decl::Kind K) {
1056  DeclContextBits.DeclKind = K;
1057  setHasExternalLexicalStorage(false);
1058  setHasExternalVisibleStorage(false);
1059  setNeedToReconcileExternalVisibleStorage(false);
1060  setHasLazyLocalLexicalLookups(false);
1061  setHasLazyExternalLexicalLookups(false);
1062  setUseQualifiedLookup(false);
1063}
1064
1065bool DeclContext::classof(const Decl *D) {
1066  switch (D->getKind()) {
1067#define DECL(NAME, BASE)
1068#define DECL_CONTEXT(NAME) case Decl::NAME:
1069#define DECL_CONTEXT_BASE(NAME)
1070#include "clang/AST/DeclNodes.inc"
1071      return true;
1072    default:
1073#define DECL(NAME, BASE)
1074#define DECL_CONTEXT_BASE(NAME)                 \
1075      if (D->getKind() >= Decl::first##NAME &&  \
1076          D->getKind() <= Decl::last##NAME)     \
1077        return true;
1078#include "clang/AST/DeclNodes.inc"
1079      return false;
1080  }
1081}
1082
1083DeclContext::~DeclContext() = default;
1084
1085/// Find the parent context of this context that will be
1086/// used for unqualified name lookup.
1087///
1088/// Generally, the parent lookup context is the semantic context. However, for
1089/// a friend function the parent lookup context is the lexical context, which
1090/// is the class in which the friend is declared.
1091DeclContext *DeclContext::getLookupParent() {
1092  // FIXME: Find a better way to identify friends.
1093  if (isa<FunctionDecl>(this))
1094    if (getParent()->getRedeclContext()->isFileContext() &&
1095        getLexicalParent()->getRedeclContext()->isRecord())
1096      return getLexicalParent();
1097
1098  // A lookup within the call operator of a lambda never looks in the lambda
1099  // class; instead, skip to the context in which that closure type is
1100  // declared.
1101  if (isLambdaCallOperator(this))
1102    return getParent()->getParent();
1103
1104  return getParent();
1105}
1106
1107const BlockDecl *DeclContext::getInnermostBlockDecl() const {
1108  const DeclContext *Ctx = this;
1109
1110  do {
1111    if (Ctx->isClosure())
1112      return cast<BlockDecl>(Ctx);
1113    Ctx = Ctx->getParent();
1114  } while (Ctx);
1115
1116  return nullptr;
1117}
1118
1119bool DeclContext::isInlineNamespace() const {
1120  return isNamespace() &&
1121         cast<NamespaceDecl>(this)->isInline();
1122}
1123
1124bool DeclContext::isStdNamespace() const {
1125  if (!isNamespace())
1126    return false;
1127
1128  const auto *ND = cast<NamespaceDecl>(this);
1129  if (ND->isInline()) {
1130    return ND->getParent()->isStdNamespace();
1131  }
1132
1133  if (!getParent()->getRedeclContext()->isTranslationUnit())
1134    return false;
1135
1136  const IdentifierInfo *II = ND->getIdentifier();
1137  return II && II->isStr("std");
1138}
1139
1140bool DeclContext::isDependentContext() const {
1141  if (isFileContext())
1142    return false;
1143
1144  if (isa<ClassTemplatePartialSpecializationDecl>(this))
1145    return true;
1146
1147  if (const auto *Record = dyn_cast<CXXRecordDecl>(this)) {
1148    if (Record->getDescribedClassTemplate())
1149      return true;
1150
1151    if (Record->isDependentLambda())
1152      return true;
1153  }
1154
1155  if (const auto *Function = dyn_cast<FunctionDecl>(this)) {
1156    if (Function->getDescribedFunctionTemplate())
1157      return true;
1158
1159    // Friend function declarations are dependent if their *lexical*
1160    // context is dependent.
1161    if (cast<Decl>(this)->getFriendObjectKind())
1162      return getLexicalParent()->isDependentContext();
1163  }
1164
1165  // FIXME: A variable template is a dependent context, but is not a
1166  // DeclContext. A context within it (such as a lambda-expression)
1167  // should be considered dependent.
1168
1169  return getParent() && getParent()->isDependentContext();
1170}
1171
1172bool DeclContext::isTransparentContext() const {
1173  if (getDeclKind() == Decl::Enum)
1174    return !cast<EnumDecl>(this)->isScoped();
1175  else if (getDeclKind() == Decl::LinkageSpec || getDeclKind() == Decl::Export)
1176    return true;
1177
1178  return false;
1179}
1180
1181static bool isLinkageSpecContext(const DeclContext *DC,
1182                                 LinkageSpecDecl::LanguageIDs ID) {
1183  while (DC->getDeclKind() != Decl::TranslationUnit) {
1184    if (DC->getDeclKind() == Decl::LinkageSpec)
1185      return cast<LinkageSpecDecl>(DC)->getLanguage() == ID;
1186    DC = DC->getLexicalParent();
1187  }
1188  return false;
1189}
1190
1191bool DeclContext::isExternCContext() const {
1192  return isLinkageSpecContext(this, LinkageSpecDecl::lang_c);
1193}
1194
1195const LinkageSpecDecl *DeclContext::getExternCContext() const {
1196  const DeclContext *DC = this;
1197  while (DC->getDeclKind() != Decl::TranslationUnit) {
1198    if (DC->getDeclKind() == Decl::LinkageSpec &&
1199        cast<LinkageSpecDecl>(DC)->getLanguage() == LinkageSpecDecl::lang_c)
1200      return cast<LinkageSpecDecl>(DC);
1201    DC = DC->getLexicalParent();
1202  }
1203  return nullptr;
1204}
1205
1206bool DeclContext::isExternCXXContext() const {
1207  return isLinkageSpecContext(this, LinkageSpecDecl::lang_cxx);
1208}
1209
1210bool DeclContext::Encloses(const DeclContext *DC) const {
1211  if (getPrimaryContext() != this)
1212    return getPrimaryContext()->Encloses(DC);
1213
1214  for (; DC; DC = DC->getParent())
1215    if (DC->getPrimaryContext() == this)
1216      return true;
1217  return false;
1218}
1219
1220DeclContext *DeclContext::getPrimaryContext() {
1221  switch (getDeclKind()) {
1222  case Decl::TranslationUnit:
1223  case Decl::ExternCContext:
1224  case Decl::LinkageSpec:
1225  case Decl::Export:
1226  case Decl::Block:
1227  case Decl::Captured:
1228  case Decl::OMPDeclareReduction:
1229  case Decl::OMPDeclareMapper:
1230  case Decl::RequiresExprBody:
1231    // There is only one DeclContext for these entities.
1232    return this;
1233
1234  case Decl::Namespace:
1235    // The original namespace is our primary context.
1236    return static_cast<NamespaceDecl *>(this)->getOriginalNamespace();
1237
1238  case Decl::ObjCMethod:
1239    return this;
1240
1241  case Decl::ObjCInterface:
1242    if (auto *OID = dyn_cast<ObjCInterfaceDecl>(this))
1243      if (auto *Def = OID->getDefinition())
1244        return Def;
1245    return this;
1246
1247  case Decl::ObjCProtocol:
1248    if (auto *OPD = dyn_cast<ObjCProtocolDecl>(this))
1249      if (auto *Def = OPD->getDefinition())
1250        return Def;
1251    return this;
1252
1253  case Decl::ObjCCategory:
1254    return this;
1255
1256  case Decl::ObjCImplementation:
1257  case Decl::ObjCCategoryImpl:
1258    return this;
1259
1260  default:
1261    if (getDeclKind() >= Decl::firstTag && getDeclKind() <= Decl::lastTag) {
1262      // If this is a tag type that has a definition or is currently
1263      // being defined, that definition is our primary context.
1264      auto *Tag = cast<TagDecl>(this);
1265
1266      if (TagDecl *Def = Tag->getDefinition())
1267        return Def;
1268
1269      if (const auto *TagTy = dyn_cast<TagType>(Tag->getTypeForDecl())) {
1270        // Note, TagType::getDecl returns the (partial) definition one exists.
1271        TagDecl *PossiblePartialDef = TagTy->getDecl();
1272        if (PossiblePartialDef->isBeingDefined())
1273          return PossiblePartialDef;
1274      } else {
1275        assert(isa<InjectedClassNameType>(Tag->getTypeForDecl()));
1276      }
1277
1278      return Tag;
1279    }
1280
1281    assert(getDeclKind() >= Decl::firstFunction &&
1282           getDeclKind() <= Decl::lastFunction &&
1283          "Unknown DeclContext kind");
1284    return this;
1285  }
1286}
1287
1288void
1289DeclContext::collectAllContexts(SmallVectorImpl<DeclContext *> &Contexts){
1290  Contexts.clear();
1291
1292  if (getDeclKind() != Decl::Namespace) {
1293    Contexts.push_back(this);
1294    return;
1295  }
1296
1297  auto *Self = static_cast<NamespaceDecl *>(this);
1298  for (NamespaceDecl *N = Self->getMostRecentDecl(); N;
1299       N = N->getPreviousDecl())
1300    Contexts.push_back(N);
1301
1302  std::reverse(Contexts.begin(), Contexts.end());
1303}
1304
1305std::pair<Decl *, Decl *>
1306DeclContext::BuildDeclChain(ArrayRef<Decl *> Decls,
1307                            bool FieldsAlreadyLoaded) {
1308  // Build up a chain of declarations via the Decl::NextInContextAndBits field.
1309  Decl *FirstNewDecl = nullptr;
1310  Decl *PrevDecl = nullptr;
1311  for (auto *D : Decls) {
1312    if (FieldsAlreadyLoaded && isa<FieldDecl>(D))
1313      continue;
1314
1315    if (PrevDecl)
1316      PrevDecl->NextInContextAndBits.setPointer(D);
1317    else
1318      FirstNewDecl = D;
1319
1320    PrevDecl = D;
1321  }
1322
1323  return std::make_pair(FirstNewDecl, PrevDecl);
1324}
1325
1326/// We have just acquired external visible storage, and we already have
1327/// built a lookup map. For every name in the map, pull in the new names from
1328/// the external storage.
1329void DeclContext::reconcileExternalVisibleStorage() const {
1330  assert(hasNeedToReconcileExternalVisibleStorage() && LookupPtr);
1331  setNeedToReconcileExternalVisibleStorage(false);
1332
1333  for (auto &Lookup : *LookupPtr)
1334    Lookup.second.setHasExternalDecls();
1335}
1336
1337/// Load the declarations within this lexical storage from an
1338/// external source.
1339/// \return \c true if any declarations were added.
1340bool
1341DeclContext::LoadLexicalDeclsFromExternalStorage() const {
1342  ExternalASTSource *Source = getParentASTContext().getExternalSource();
1343  assert(hasExternalLexicalStorage() && Source && "No external storage?");
1344
1345  // Notify that we have a DeclContext that is initializing.
1346  ExternalASTSource::Deserializing ADeclContext(Source);
1347
1348  // Load the external declarations, if any.
1349  SmallVector<Decl*, 64> Decls;
1350  setHasExternalLexicalStorage(false);
1351  Source->FindExternalLexicalDecls(this, Decls);
1352
1353  if (Decls.empty())
1354    return false;
1355
1356  // We may have already loaded just the fields of this record, in which case
1357  // we need to ignore them.
1358  bool FieldsAlreadyLoaded = false;
1359  if (const auto *RD = dyn_cast<RecordDecl>(this))
1360    FieldsAlreadyLoaded = RD->hasLoadedFieldsFromExternalStorage();
1361
1362  // Splice the newly-read declarations into the beginning of the list
1363  // of declarations.
1364  Decl *ExternalFirst, *ExternalLast;
1365  std::tie(ExternalFirst, ExternalLast) =
1366      BuildDeclChain(Decls, FieldsAlreadyLoaded);
1367  ExternalLast->NextInContextAndBits.setPointer(FirstDecl);
1368  FirstDecl = ExternalFirst;
1369  if (!LastDecl)
1370    LastDecl = ExternalLast;
1371  return true;
1372}
1373
1374DeclContext::lookup_result
1375ExternalASTSource::SetNoExternalVisibleDeclsForName(const DeclContext *DC,
1376                                                    DeclarationName Name) {
1377  ASTContext &Context = DC->getParentASTContext();
1378  StoredDeclsMap *Map;
1379  if (!(Map = DC->LookupPtr))
1380    Map = DC->CreateStoredDeclsMap(Context);
1381  if (DC->hasNeedToReconcileExternalVisibleStorage())
1382    DC->reconcileExternalVisibleStorage();
1383
1384  (*Map)[Name].removeExternalDecls();
1385
1386  return DeclContext::lookup_result();
1387}
1388
1389DeclContext::lookup_result
1390ExternalASTSource::SetExternalVisibleDeclsForName(const DeclContext *DC,
1391                                                  DeclarationName Name,
1392                                                  ArrayRef<NamedDecl*> Decls) {
1393  ASTContext &Context = DC->getParentASTContext();
1394  StoredDeclsMap *Map;
1395  if (!(Map = DC->LookupPtr))
1396    Map = DC->CreateStoredDeclsMap(Context);
1397  if (DC->hasNeedToReconcileExternalVisibleStorage())
1398    DC->reconcileExternalVisibleStorage();
1399
1400  StoredDeclsList &List = (*Map)[Name];
1401
1402  // Clear out any old external visible declarations, to avoid quadratic
1403  // performance in the redeclaration checks below.
1404  List.removeExternalDecls();
1405
1406  if (!List.isNull()) {
1407    // We have both existing declarations and new declarations for this name.
1408    // Some of the declarations may simply replace existing ones. Handle those
1409    // first.
1410    llvm::SmallVector<unsigned, 8> Skip;
1411    for (unsigned I = 0, N = Decls.size(); I != N; ++I)
1412      if (List.HandleRedeclaration(Decls[I], /*IsKnownNewer*/false))
1413        Skip.push_back(I);
1414    Skip.push_back(Decls.size());
1415
1416    // Add in any new declarations.
1417    unsigned SkipPos = 0;
1418    for (unsigned I = 0, N = Decls.size(); I != N; ++I) {
1419      if (I == Skip[SkipPos])
1420        ++SkipPos;
1421      else
1422        List.AddSubsequentDecl(Decls[I]);
1423    }
1424  } else {
1425    // Convert the array to a StoredDeclsList.
1426    for (auto *D : Decls) {
1427      if (List.isNull())
1428        List.setOnlyValue(D);
1429      else
1430        List.AddSubsequentDecl(D);
1431    }
1432  }
1433
1434  return List.getLookupResult();
1435}
1436
1437DeclContext::decl_iterator DeclContext::decls_begin() const {
1438  if (hasExternalLexicalStorage())
1439    LoadLexicalDeclsFromExternalStorage();
1440  return decl_iterator(FirstDecl);
1441}
1442
1443bool DeclContext::decls_empty() const {
1444  if (hasExternalLexicalStorage())
1445    LoadLexicalDeclsFromExternalStorage();
1446
1447  return !FirstDecl;
1448}
1449
1450bool DeclContext::containsDecl(Decl *D) const {
1451  return (D->getLexicalDeclContext() == this &&
1452          (D->NextInContextAndBits.getPointer() || D == LastDecl));
1453}
1454
1455bool DeclContext::containsDeclAndLoad(Decl *D) const {
1456  if (hasExternalLexicalStorage())
1457    LoadLexicalDeclsFromExternalStorage();
1458  return containsDecl(D);
1459}
1460
1461/// shouldBeHidden - Determine whether a declaration which was declared
1462/// within its semantic context should be invisible to qualified name lookup.
1463static bool shouldBeHidden(NamedDecl *D) {
1464  // Skip unnamed declarations.
1465  if (!D->getDeclName())
1466    return true;
1467
1468  // Skip entities that can't be found by name lookup into a particular
1469  // context.
1470  if ((D->getIdentifierNamespace() == 0 && !isa<UsingDirectiveDecl>(D)) ||
1471      D->isTemplateParameter())
1472    return true;
1473
1474  // Skip friends and local extern declarations unless they're the first
1475  // declaration of the entity.
1476  if ((D->isLocalExternDecl() || D->getFriendObjectKind()) &&
1477      D != D->getCanonicalDecl())
1478    return true;
1479
1480  // Skip template specializations.
1481  // FIXME: This feels like a hack. Should DeclarationName support
1482  // template-ids, or is there a better way to keep specializations
1483  // from being visible?
1484  if (isa<ClassTemplateSpecializationDecl>(D))
1485    return true;
1486  if (auto *FD = dyn_cast<FunctionDecl>(D))
1487    if (FD->isFunctionTemplateSpecialization())
1488      return true;
1489
1490  // Hide destructors that are invalid. There should always be one destructor,
1491  // but if it is an invalid decl, another one is created. We need to hide the
1492  // invalid one from places that expect exactly one destructor, like the
1493  // serialization code.
1494  if (isa<CXXDestructorDecl>(D) && D->isInvalidDecl())
1495    return true;
1496
1497  return false;
1498}
1499
1500void DeclContext::removeDecl(Decl *D) {
1501  assert(D->getLexicalDeclContext() == this &&
1502         "decl being removed from non-lexical context");
1503  assert((D->NextInContextAndBits.getPointer() || D == LastDecl) &&
1504         "decl is not in decls list");
1505
1506  // Remove D from the decl chain.  This is O(n) but hopefully rare.
1507  if (D == FirstDecl) {
1508    if (D == LastDecl)
1509      FirstDecl = LastDecl = nullptr;
1510    else
1511      FirstDecl = D->NextInContextAndBits.getPointer();
1512  } else {
1513    for (Decl *I = FirstDecl; true; I = I->NextInContextAndBits.getPointer()) {
1514      assert(I && "decl not found in linked list");
1515      if (I->NextInContextAndBits.getPointer() == D) {
1516        I->NextInContextAndBits.setPointer(D->NextInContextAndBits.getPointer());
1517        if (D == LastDecl) LastDecl = I;
1518        break;
1519      }
1520    }
1521  }
1522
1523  // Mark that D is no longer in the decl chain.
1524  D->NextInContextAndBits.setPointer(nullptr);
1525
1526  // Remove D from the lookup table if necessary.
1527  if (isa<NamedDecl>(D)) {
1528    auto *ND = cast<NamedDecl>(D);
1529
1530    // Do not try to remove the declaration if that is invisible to qualified
1531    // lookup.  E.g. template specializations are skipped.
1532    if (shouldBeHidden(ND))
1533      return;
1534
1535    // Remove only decls that have a name
1536    if (!ND->getDeclName())
1537      return;
1538
1539    auto *DC = D->getDeclContext();
1540    do {
1541      StoredDeclsMap *Map = DC->getPrimaryContext()->LookupPtr;
1542      if (Map) {
1543        StoredDeclsMap::iterator Pos = Map->find(ND->getDeclName());
1544        assert(Pos != Map->end() && "no lookup entry for decl");
1545        // Remove the decl only if it is contained.
1546        StoredDeclsList::DeclsTy *Vec = Pos->second.getAsVector();
1547        if ((Vec && is_contained(*Vec, ND)) || Pos->second.getAsDecl() == ND)
1548          Pos->second.remove(ND);
1549      }
1550    } while (DC->isTransparentContext() && (DC = DC->getParent()));
1551  }
1552}
1553
1554void DeclContext::addHiddenDecl(Decl *D) {
1555  assert(D->getLexicalDeclContext() == this &&
1556         "Decl inserted into wrong lexical context");
1557  assert(!D->getNextDeclInContext() && D != LastDecl &&
1558         "Decl already inserted into a DeclContext");
1559
1560  if (FirstDecl) {
1561    LastDecl->NextInContextAndBits.setPointer(D);
1562    LastDecl = D;
1563  } else {
1564    FirstDecl = LastDecl = D;
1565  }
1566
1567  // Notify a C++ record declaration that we've added a member, so it can
1568  // update its class-specific state.
1569  if (auto *Record = dyn_cast<CXXRecordDecl>(this))
1570    Record->addedMember(D);
1571
1572  // If this is a newly-created (not de-serialized) import declaration, wire
1573  // it in to the list of local import declarations.
1574  if (!D->isFromASTFile()) {
1575    if (auto *Import = dyn_cast<ImportDecl>(D))
1576      D->getASTContext().addedLocalImportDecl(Import);
1577  }
1578}
1579
1580void DeclContext::addDecl(Decl *D) {
1581  addHiddenDecl(D);
1582
1583  if (auto *ND = dyn_cast<NamedDecl>(D))
1584    ND->getDeclContext()->getPrimaryContext()->
1585        makeDeclVisibleInContextWithFlags(ND, false, true);
1586}
1587
1588void DeclContext::addDeclInternal(Decl *D) {
1589  addHiddenDecl(D);
1590
1591  if (auto *ND = dyn_cast<NamedDecl>(D))
1592    ND->getDeclContext()->getPrimaryContext()->
1593        makeDeclVisibleInContextWithFlags(ND, true, true);
1594}
1595
1596/// buildLookup - Build the lookup data structure with all of the
1597/// declarations in this DeclContext (and any other contexts linked
1598/// to it or transparent contexts nested within it) and return it.
1599///
1600/// Note that the produced map may miss out declarations from an
1601/// external source. If it does, those entries will be marked with
1602/// the 'hasExternalDecls' flag.
1603StoredDeclsMap *DeclContext::buildLookup() {
1604  assert(this == getPrimaryContext() && "buildLookup called on non-primary DC");
1605
1606  if (!hasLazyLocalLexicalLookups() &&
1607      !hasLazyExternalLexicalLookups())
1608    return LookupPtr;
1609
1610  SmallVector<DeclContext *, 2> Contexts;
1611  collectAllContexts(Contexts);
1612
1613  if (hasLazyExternalLexicalLookups()) {
1614    setHasLazyExternalLexicalLookups(false);
1615    for (auto *DC : Contexts) {
1616      if (DC->hasExternalLexicalStorage()) {
1617        bool LoadedDecls = DC->LoadLexicalDeclsFromExternalStorage();
1618        setHasLazyLocalLexicalLookups(
1619            hasLazyLocalLexicalLookups() | LoadedDecls );
1620      }
1621    }
1622
1623    if (!hasLazyLocalLexicalLookups())
1624      return LookupPtr;
1625  }
1626
1627  for (auto *DC : Contexts)
1628    buildLookupImpl(DC, hasExternalVisibleStorage());
1629
1630  // We no longer have any lazy decls.
1631  setHasLazyLocalLexicalLookups(false);
1632  return LookupPtr;
1633}
1634
1635/// buildLookupImpl - Build part of the lookup data structure for the
1636/// declarations contained within DCtx, which will either be this
1637/// DeclContext, a DeclContext linked to it, or a transparent context
1638/// nested within it.
1639void DeclContext::buildLookupImpl(DeclContext *DCtx, bool Internal) {
1640  for (auto *D : DCtx->noload_decls()) {
1641    // Insert this declaration into the lookup structure, but only if
1642    // it's semantically within its decl context. Any other decls which
1643    // should be found in this context are added eagerly.
1644    //
1645    // If it's from an AST file, don't add it now. It'll get handled by
1646    // FindExternalVisibleDeclsByName if needed. Exception: if we're not
1647    // in C++, we do not track external visible decls for the TU, so in
1648    // that case we need to collect them all here.
1649    if (auto *ND = dyn_cast<NamedDecl>(D))
1650      if (ND->getDeclContext() == DCtx && !shouldBeHidden(ND) &&
1651          (!ND->isFromASTFile() ||
1652           (isTranslationUnit() &&
1653            !getParentASTContext().getLangOpts().CPlusPlus)))
1654        makeDeclVisibleInContextImpl(ND, Internal);
1655
1656    // If this declaration is itself a transparent declaration context
1657    // or inline namespace, add the members of this declaration of that
1658    // context (recursively).
1659    if (auto *InnerCtx = dyn_cast<DeclContext>(D))
1660      if (InnerCtx->isTransparentContext() || InnerCtx->isInlineNamespace())
1661        buildLookupImpl(InnerCtx, Internal);
1662  }
1663}
1664
1665NamedDecl *const DeclContextLookupResult::SingleElementDummyList = nullptr;
1666
1667DeclContext::lookup_result
1668DeclContext::lookup(DeclarationName Name) const {
1669  assert(getDeclKind() != Decl::LinkageSpec &&
1670         getDeclKind() != Decl::Export &&
1671         "should not perform lookups into transparent contexts");
1672
1673  const DeclContext *PrimaryContext = getPrimaryContext();
1674  if (PrimaryContext != this)
1675    return PrimaryContext->lookup(Name);
1676
1677  // If we have an external source, ensure that any later redeclarations of this
1678  // context have been loaded, since they may add names to the result of this
1679  // lookup (or add external visible storage).
1680  ExternalASTSource *Source = getParentASTContext().getExternalSource();
1681  if (Source)
1682    (void)cast<Decl>(this)->getMostRecentDecl();
1683
1684  if (hasExternalVisibleStorage()) {
1685    assert(Source && "external visible storage but no external source?");
1686
1687    if (hasNeedToReconcileExternalVisibleStorage())
1688      reconcileExternalVisibleStorage();
1689
1690    StoredDeclsMap *Map = LookupPtr;
1691
1692    if (hasLazyLocalLexicalLookups() ||
1693        hasLazyExternalLexicalLookups())
1694      // FIXME: Make buildLookup const?
1695      Map = const_cast<DeclContext*>(this)->buildLookup();
1696
1697    if (!Map)
1698      Map = CreateStoredDeclsMap(getParentASTContext());
1699
1700    // If we have a lookup result with no external decls, we are done.
1701    std::pair<StoredDeclsMap::iterator, bool> R =
1702        Map->insert(std::make_pair(Name, StoredDeclsList()));
1703    if (!R.second && !R.first->second.hasExternalDecls())
1704      return R.first->second.getLookupResult();
1705
1706    if (Source->FindExternalVisibleDeclsByName(this, Name) || !R.second) {
1707      if (StoredDeclsMap *Map = LookupPtr) {
1708        StoredDeclsMap::iterator I = Map->find(Name);
1709        if (I != Map->end())
1710          return I->second.getLookupResult();
1711      }
1712    }
1713
1714    return {};
1715  }
1716
1717  StoredDeclsMap *Map = LookupPtr;
1718  if (hasLazyLocalLexicalLookups() ||
1719      hasLazyExternalLexicalLookups())
1720    Map = const_cast<DeclContext*>(this)->buildLookup();
1721
1722  if (!Map)
1723    return {};
1724
1725  StoredDeclsMap::iterator I = Map->find(Name);
1726  if (I == Map->end())
1727    return {};
1728
1729  return I->second.getLookupResult();
1730}
1731
1732DeclContext::lookup_result
1733DeclContext::noload_lookup(DeclarationName Name) {
1734  assert(getDeclKind() != Decl::LinkageSpec &&
1735         getDeclKind() != Decl::Export &&
1736         "should not perform lookups into transparent contexts");
1737
1738  DeclContext *PrimaryContext = getPrimaryContext();
1739  if (PrimaryContext != this)
1740    return PrimaryContext->noload_lookup(Name);
1741
1742  loadLazyLocalLexicalLookups();
1743  StoredDeclsMap *Map = LookupPtr;
1744  if (!Map)
1745    return {};
1746
1747  StoredDeclsMap::iterator I = Map->find(Name);
1748  return I != Map->end() ? I->second.getLookupResult()
1749                         : lookup_result();
1750}
1751
1752// If we have any lazy lexical declarations not in our lookup map, add them
1753// now. Don't import any external declarations, not even if we know we have
1754// some missing from the external visible lookups.
1755void DeclContext::loadLazyLocalLexicalLookups() {
1756  if (hasLazyLocalLexicalLookups()) {
1757    SmallVector<DeclContext *, 2> Contexts;
1758    collectAllContexts(Contexts);
1759    for (auto *Context : Contexts)
1760      buildLookupImpl(Context, hasExternalVisibleStorage());
1761    setHasLazyLocalLexicalLookups(false);
1762  }
1763}
1764
1765void DeclContext::localUncachedLookup(DeclarationName Name,
1766                                      SmallVectorImpl<NamedDecl *> &Results) {
1767  Results.clear();
1768
1769  // If there's no external storage, just perform a normal lookup and copy
1770  // the results.
1771  if (!hasExternalVisibleStorage() && !hasExternalLexicalStorage() && Name) {
1772    lookup_result LookupResults = lookup(Name);
1773    Results.insert(Results.end(), LookupResults.begin(), LookupResults.end());
1774    return;
1775  }
1776
1777  // If we have a lookup table, check there first. Maybe we'll get lucky.
1778  // FIXME: Should we be checking these flags on the primary context?
1779  if (Name && !hasLazyLocalLexicalLookups() &&
1780      !hasLazyExternalLexicalLookups()) {
1781    if (StoredDeclsMap *Map = LookupPtr) {
1782      StoredDeclsMap::iterator Pos = Map->find(Name);
1783      if (Pos != Map->end()) {
1784        Results.insert(Results.end(),
1785                       Pos->second.getLookupResult().begin(),
1786                       Pos->second.getLookupResult().end());
1787        return;
1788      }
1789    }
1790  }
1791
1792  // Slow case: grovel through the declarations in our chain looking for
1793  // matches.
1794  // FIXME: If we have lazy external declarations, this will not find them!
1795  // FIXME: Should we CollectAllContexts and walk them all here?
1796  for (Decl *D = FirstDecl; D; D = D->getNextDeclInContext()) {
1797    if (auto *ND = dyn_cast<NamedDecl>(D))
1798      if (ND->getDeclName() == Name)
1799        Results.push_back(ND);
1800  }
1801}
1802
1803DeclContext *DeclContext::getRedeclContext() {
1804  DeclContext *Ctx = this;
1805
1806  // In C, a record type is the redeclaration context for its fields only. If
1807  // we arrive at a record context after skipping anything else, we should skip
1808  // the record as well. Currently, this means skipping enumerations because
1809  // they're the only transparent context that can exist within a struct or
1810  // union.
1811  bool SkipRecords = getDeclKind() == Decl::Kind::Enum &&
1812                     !getParentASTContext().getLangOpts().CPlusPlus;
1813
1814  // Skip through contexts to get to the redeclaration context. Transparent
1815  // contexts are always skipped.
1816  while ((SkipRecords && Ctx->isRecord()) || Ctx->isTransparentContext())
1817    Ctx = Ctx->getParent();
1818  return Ctx;
1819}
1820
1821DeclContext *DeclContext::getEnclosingNamespaceContext() {
1822  DeclContext *Ctx = this;
1823  // Skip through non-namespace, non-translation-unit contexts.
1824  while (!Ctx->isFileContext())
1825    Ctx = Ctx->getParent();
1826  return Ctx->getPrimaryContext();
1827}
1828
1829RecordDecl *DeclContext::getOuterLexicalRecordContext() {
1830  // Loop until we find a non-record context.
1831  RecordDecl *OutermostRD = nullptr;
1832  DeclContext *DC = this;
1833  while (DC->isRecord()) {
1834    OutermostRD = cast<RecordDecl>(DC);
1835    DC = DC->getLexicalParent();
1836  }
1837  return OutermostRD;
1838}
1839
1840bool DeclContext::InEnclosingNamespaceSetOf(const DeclContext *O) const {
1841  // For non-file contexts, this is equivalent to Equals.
1842  if (!isFileContext())
1843    return O->Equals(this);
1844
1845  do {
1846    if (O->Equals(this))
1847      return true;
1848
1849    const auto *NS = dyn_cast<NamespaceDecl>(O);
1850    if (!NS || !NS->isInline())
1851      break;
1852    O = NS->getParent();
1853  } while (O);
1854
1855  return false;
1856}
1857
1858void DeclContext::makeDeclVisibleInContext(NamedDecl *D) {
1859  DeclContext *PrimaryDC = this->getPrimaryContext();
1860  DeclContext *DeclDC = D->getDeclContext()->getPrimaryContext();
1861  // If the decl is being added outside of its semantic decl context, we
1862  // need to ensure that we eagerly build the lookup information for it.
1863  PrimaryDC->makeDeclVisibleInContextWithFlags(D, false, PrimaryDC == DeclDC);
1864}
1865
1866void DeclContext::makeDeclVisibleInContextWithFlags(NamedDecl *D, bool Internal,
1867                                                    bool Recoverable) {
1868  assert(this == getPrimaryContext() && "expected a primary DC");
1869
1870  if (!isLookupContext()) {
1871    if (isTransparentContext())
1872      getParent()->getPrimaryContext()
1873        ->makeDeclVisibleInContextWithFlags(D, Internal, Recoverable);
1874    return;
1875  }
1876
1877  // Skip declarations which should be invisible to name lookup.
1878  if (shouldBeHidden(D))
1879    return;
1880
1881  // If we already have a lookup data structure, perform the insertion into
1882  // it. If we might have externally-stored decls with this name, look them
1883  // up and perform the insertion. If this decl was declared outside its
1884  // semantic context, buildLookup won't add it, so add it now.
1885  //
1886  // FIXME: As a performance hack, don't add such decls into the translation
1887  // unit unless we're in C++, since qualified lookup into the TU is never
1888  // performed.
1889  if (LookupPtr || hasExternalVisibleStorage() ||
1890      ((!Recoverable || D->getDeclContext() != D->getLexicalDeclContext()) &&
1891       (getParentASTContext().getLangOpts().CPlusPlus ||
1892        !isTranslationUnit()))) {
1893    // If we have lazily omitted any decls, they might have the same name as
1894    // the decl which we are adding, so build a full lookup table before adding
1895    // this decl.
1896    buildLookup();
1897    makeDeclVisibleInContextImpl(D, Internal);
1898  } else {
1899    setHasLazyLocalLexicalLookups(true);
1900  }
1901
1902  // If we are a transparent context or inline namespace, insert into our
1903  // parent context, too. This operation is recursive.
1904  if (isTransparentContext() || isInlineNamespace())
1905    getParent()->getPrimaryContext()->
1906        makeDeclVisibleInContextWithFlags(D, Internal, Recoverable);
1907
1908  auto *DCAsDecl = cast<Decl>(this);
1909  // Notify that a decl was made visible unless we are a Tag being defined.
1910  if (!(isa<TagDecl>(DCAsDecl) && cast<TagDecl>(DCAsDecl)->isBeingDefined()))
1911    if (ASTMutationListener *L = DCAsDecl->getASTMutationListener())
1912      L->AddedVisibleDecl(this, D);
1913}
1914
1915void DeclContext::makeDeclVisibleInContextImpl(NamedDecl *D, bool Internal) {
1916  // Find or create the stored declaration map.
1917  StoredDeclsMap *Map = LookupPtr;
1918  if (!Map) {
1919    ASTContext *C = &getParentASTContext();
1920    Map = CreateStoredDeclsMap(*C);
1921  }
1922
1923  // If there is an external AST source, load any declarations it knows about
1924  // with this declaration's name.
1925  // If the lookup table contains an entry about this name it means that we
1926  // have already checked the external source.
1927  if (!Internal)
1928    if (ExternalASTSource *Source = getParentASTContext().getExternalSource())
1929      if (hasExternalVisibleStorage() &&
1930          Map->find(D->getDeclName()) == Map->end())
1931        Source->FindExternalVisibleDeclsByName(this, D->getDeclName());
1932
1933  // Insert this declaration into the map.
1934  StoredDeclsList &DeclNameEntries = (*Map)[D->getDeclName()];
1935
1936  if (Internal) {
1937    // If this is being added as part of loading an external declaration,
1938    // this may not be the only external declaration with this name.
1939    // In this case, we never try to replace an existing declaration; we'll
1940    // handle that when we finalize the list of declarations for this name.
1941    DeclNameEntries.setHasExternalDecls();
1942    DeclNameEntries.AddSubsequentDecl(D);
1943    return;
1944  }
1945
1946  if (DeclNameEntries.isNull()) {
1947    DeclNameEntries.setOnlyValue(D);
1948    return;
1949  }
1950
1951  if (DeclNameEntries.HandleRedeclaration(D, /*IsKnownNewer*/!Internal)) {
1952    // This declaration has replaced an existing one for which
1953    // declarationReplaces returns true.
1954    return;
1955  }
1956
1957  // Put this declaration into the appropriate slot.
1958  DeclNameEntries.AddSubsequentDecl(D);
1959}
1960
1961UsingDirectiveDecl *DeclContext::udir_iterator::operator*() const {
1962  return cast<UsingDirectiveDecl>(*I);
1963}
1964
1965/// Returns iterator range [First, Last) of UsingDirectiveDecls stored within
1966/// this context.
1967DeclContext::udir_range DeclContext::using_directives() const {
1968  // FIXME: Use something more efficient than normal lookup for using
1969  // directives. In C++, using directives are looked up more than anything else.
1970  lookup_result Result = lookup(UsingDirectiveDecl::getName());
1971  return udir_range(Result.begin(), Result.end());
1972}
1973
1974//===----------------------------------------------------------------------===//
1975// Creation and Destruction of StoredDeclsMaps.                               //
1976//===----------------------------------------------------------------------===//
1977
1978StoredDeclsMap *DeclContext::CreateStoredDeclsMap(ASTContext &C) const {
1979  assert(!LookupPtr && "context already has a decls map");
1980  assert(getPrimaryContext() == this &&
1981         "creating decls map on non-primary context");
1982
1983  StoredDeclsMap *M;
1984  bool Dependent = isDependentContext();
1985  if (Dependent)
1986    M = new DependentStoredDeclsMap();
1987  else
1988    M = new StoredDeclsMap();
1989  M->Previous = C.LastSDM;
1990  C.LastSDM = llvm::PointerIntPair<StoredDeclsMap*,1>(M, Dependent);
1991  LookupPtr = M;
1992  return M;
1993}
1994
1995void ASTContext::ReleaseDeclContextMaps() {
1996  // It's okay to delete DependentStoredDeclsMaps via a StoredDeclsMap
1997  // pointer because the subclass doesn't add anything that needs to
1998  // be deleted.
1999  StoredDeclsMap::DestroyAll(LastSDM.getPointer(), LastSDM.getInt());
2000}
2001
2002void StoredDeclsMap::DestroyAll(StoredDeclsMap *Map, bool Dependent) {
2003  while (Map) {
2004    // Advance the iteration before we invalidate memory.
2005    llvm::PointerIntPair<StoredDeclsMap*,1> Next = Map->Previous;
2006
2007    if (Dependent)
2008      delete static_cast<DependentStoredDeclsMap*>(Map);
2009    else
2010      delete Map;
2011
2012    Map = Next.getPointer();
2013    Dependent = Next.getInt();
2014  }
2015}
2016
2017DependentDiagnostic *DependentDiagnostic::Create(ASTContext &C,
2018                                                 DeclContext *Parent,
2019                                           const PartialDiagnostic &PDiag) {
2020  assert(Parent->isDependentContext()
2021         && "cannot iterate dependent diagnostics of non-dependent context");
2022  Parent = Parent->getPrimaryContext();
2023  if (!Parent->LookupPtr)
2024    Parent->CreateStoredDeclsMap(C);
2025
2026  auto *Map = static_cast<DependentStoredDeclsMap *>(Parent->LookupPtr);
2027
2028  // Allocate the copy of the PartialDiagnostic via the ASTContext's
2029  // BumpPtrAllocator, rather than the ASTContext itself.
2030  PartialDiagnostic::Storage *DiagStorage = nullptr;
2031  if (PDiag.hasStorage())
2032    DiagStorage = new (C) PartialDiagnostic::Storage;
2033
2034  auto *DD = new (C) DependentDiagnostic(PDiag, DiagStorage);
2035
2036  // TODO: Maybe we shouldn't reverse the order during insertion.
2037  DD->NextDiagnostic = Map->FirstDiagnostic;
2038  Map->FirstDiagnostic = DD;
2039
2040  return DD;
2041}
2042