1 //===--- ASTWriterDecl.cpp - Declaration Serialization --------------------===//
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 serialization for Declarations.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Serialization/ASTWriter.h"
15 #include "ASTCommon.h"
16 #include "clang/AST/DeclCXX.h"
17 #include "clang/AST/DeclContextInternals.h"
18 #include "clang/AST/DeclTemplate.h"
19 #include "clang/AST/DeclVisitor.h"
20 #include "clang/AST/Expr.h"
21 #include "clang/Basic/SourceManager.h"
22 #include "clang/Serialization/ASTReader.h"
23 #include "llvm/ADT/Twine.h"
24 #include "llvm/Bitcode/BitstreamWriter.h"
25 #include "llvm/Support/ErrorHandling.h"
26 using namespace clang;
27 using namespace serialization;
28 
29 //===----------------------------------------------------------------------===//
30 // Declaration serialization
31 //===----------------------------------------------------------------------===//
32 
33 namespace clang {
34   class ASTDeclWriter : public DeclVisitor<ASTDeclWriter, void> {
35 
36     ASTWriter &Writer;
37     ASTContext &Context;
38     typedef ASTWriter::RecordData RecordData;
39     RecordData &Record;
40 
41   public:
42     serialization::DeclCode Code;
43     unsigned AbbrevToUse;
44 
45     ASTDeclWriter(ASTWriter &Writer, ASTContext &Context, RecordData &Record)
46       : Writer(Writer), Context(Context), Record(Record) {
47     }
48 
49     void Visit(Decl *D);
50 
51     void VisitDecl(Decl *D);
52     void VisitTranslationUnitDecl(TranslationUnitDecl *D);
53     void VisitNamedDecl(NamedDecl *D);
54     void VisitLabelDecl(LabelDecl *LD);
55     void VisitNamespaceDecl(NamespaceDecl *D);
56     void VisitUsingDirectiveDecl(UsingDirectiveDecl *D);
57     void VisitNamespaceAliasDecl(NamespaceAliasDecl *D);
58     void VisitTypeDecl(TypeDecl *D);
59     void VisitTypedefNameDecl(TypedefNameDecl *D);
60     void VisitTypedefDecl(TypedefDecl *D);
61     void VisitTypeAliasDecl(TypeAliasDecl *D);
62     void VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D);
63     void VisitTagDecl(TagDecl *D);
64     void VisitEnumDecl(EnumDecl *D);
65     void VisitRecordDecl(RecordDecl *D);
66     void VisitCXXRecordDecl(CXXRecordDecl *D);
67     void VisitClassTemplateSpecializationDecl(
68                                             ClassTemplateSpecializationDecl *D);
69     void VisitClassTemplatePartialSpecializationDecl(
70                                      ClassTemplatePartialSpecializationDecl *D);
71     void VisitVarTemplateSpecializationDecl(VarTemplateSpecializationDecl *D);
72     void VisitVarTemplatePartialSpecializationDecl(
73         VarTemplatePartialSpecializationDecl *D);
74     void VisitClassScopeFunctionSpecializationDecl(
75                                        ClassScopeFunctionSpecializationDecl *D);
76     void VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
77     void VisitValueDecl(ValueDecl *D);
78     void VisitEnumConstantDecl(EnumConstantDecl *D);
79     void VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D);
80     void VisitDeclaratorDecl(DeclaratorDecl *D);
81     void VisitFunctionDecl(FunctionDecl *D);
82     void VisitCXXMethodDecl(CXXMethodDecl *D);
83     void VisitCXXConstructorDecl(CXXConstructorDecl *D);
84     void VisitCXXDestructorDecl(CXXDestructorDecl *D);
85     void VisitCXXConversionDecl(CXXConversionDecl *D);
86     void VisitFieldDecl(FieldDecl *D);
87     void VisitMSPropertyDecl(MSPropertyDecl *D);
88     void VisitIndirectFieldDecl(IndirectFieldDecl *D);
89     void VisitVarDecl(VarDecl *D);
90     void VisitImplicitParamDecl(ImplicitParamDecl *D);
91     void VisitParmVarDecl(ParmVarDecl *D);
92     void VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
93     void VisitTemplateDecl(TemplateDecl *D);
94     void VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D);
95     void VisitClassTemplateDecl(ClassTemplateDecl *D);
96     void VisitVarTemplateDecl(VarTemplateDecl *D);
97     void VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
98     void VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
99     void VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D);
100     void VisitUsingDecl(UsingDecl *D);
101     void VisitUsingShadowDecl(UsingShadowDecl *D);
102     void VisitLinkageSpecDecl(LinkageSpecDecl *D);
103     void VisitFileScopeAsmDecl(FileScopeAsmDecl *D);
104     void VisitImportDecl(ImportDecl *D);
105     void VisitAccessSpecDecl(AccessSpecDecl *D);
106     void VisitFriendDecl(FriendDecl *D);
107     void VisitFriendTemplateDecl(FriendTemplateDecl *D);
108     void VisitStaticAssertDecl(StaticAssertDecl *D);
109     void VisitBlockDecl(BlockDecl *D);
110     void VisitCapturedDecl(CapturedDecl *D);
111     void VisitEmptyDecl(EmptyDecl *D);
112 
113     void VisitDeclContext(DeclContext *DC, uint64_t LexicalOffset,
114                           uint64_t VisibleOffset);
115     template <typename T> void VisitRedeclarable(Redeclarable<T> *D);
116 
117 
118     // FIXME: Put in the same order is DeclNodes.td?
119     void VisitObjCMethodDecl(ObjCMethodDecl *D);
120     void VisitObjCContainerDecl(ObjCContainerDecl *D);
121     void VisitObjCInterfaceDecl(ObjCInterfaceDecl *D);
122     void VisitObjCIvarDecl(ObjCIvarDecl *D);
123     void VisitObjCProtocolDecl(ObjCProtocolDecl *D);
124     void VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D);
125     void VisitObjCCategoryDecl(ObjCCategoryDecl *D);
126     void VisitObjCImplDecl(ObjCImplDecl *D);
127     void VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D);
128     void VisitObjCImplementationDecl(ObjCImplementationDecl *D);
129     void VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D);
130     void VisitObjCPropertyDecl(ObjCPropertyDecl *D);
131     void VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D);
132     void VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D);
133 
134     void AddFunctionDefinition(const FunctionDecl *FD) {
135       assert(FD->doesThisDeclarationHaveABody());
136       if (auto *CD = dyn_cast<CXXConstructorDecl>(FD)) {
137         Record.push_back(CD->NumCtorInitializers);
138         if (CD->NumCtorInitializers)
139           Writer.AddCXXCtorInitializersRef(
140               llvm::makeArrayRef(CD->init_begin(), CD->init_end()), Record);
141       }
142       Writer.AddStmt(FD->getBody());
143     }
144 
145     /// Get the specialization decl from an entry in the specialization list.
146     template <typename EntryType>
147     typename RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::DeclType *
148     getSpecializationDecl(EntryType &T) {
149       return RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::getDecl(&T);
150     }
151 
152     /// Get the list of partial specializations from a template's common ptr.
153     template<typename T>
154     decltype(T::PartialSpecializations) &getPartialSpecializations(T *Common) {
155       return Common->PartialSpecializations;
156     }
157     ArrayRef<Decl> getPartialSpecializations(FunctionTemplateDecl::Common *) {
158       return None;
159     }
160 
161     template<typename Decl>
162     void AddTemplateSpecializations(Decl *D) {
163       auto *Common = D->getCommonPtr();
164 
165       // If we have any lazy specializations, and the external AST source is
166       // our chained AST reader, we can just write out the DeclIDs. Otherwise,
167       // we need to resolve them to actual declarations.
168       if (Writer.Chain != Writer.Context->getExternalSource() &&
169           Common->LazySpecializations) {
170         D->LoadLazySpecializations();
171         assert(!Common->LazySpecializations);
172       }
173 
174       auto &Specializations = Common->Specializations;
175       auto &&PartialSpecializations = getPartialSpecializations(Common);
176       ArrayRef<DeclID> LazySpecializations;
177       if (auto *LS = Common->LazySpecializations)
178         LazySpecializations = ArrayRef<DeclID>(LS + 1, LS + 1 + LS[0]);
179 
180       Record.push_back(Specializations.size() +
181                        PartialSpecializations.size() +
182                        LazySpecializations.size());
183       for (auto &Entry : Specializations) {
184         auto *D = getSpecializationDecl(Entry);
185         assert(D->isCanonicalDecl() && "non-canonical decl in set");
186         Writer.AddDeclRef(D, Record);
187       }
188       for (auto &Entry : PartialSpecializations) {
189         auto *D = getSpecializationDecl(Entry);
190         assert(D->isCanonicalDecl() && "non-canonical decl in set");
191         Writer.AddDeclRef(D, Record);
192       }
193       Record.append(LazySpecializations.begin(), LazySpecializations.end());
194     }
195   };
196 }
197 
198 void ASTDeclWriter::Visit(Decl *D) {
199   DeclVisitor<ASTDeclWriter>::Visit(D);
200 
201   // Source locations require array (variable-length) abbreviations.  The
202   // abbreviation infrastructure requires that arrays are encoded last, so
203   // we handle it here in the case of those classes derived from DeclaratorDecl
204   if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D)){
205     Writer.AddTypeSourceInfo(DD->getTypeSourceInfo(), Record);
206   }
207 
208   // Handle FunctionDecl's body here and write it after all other Stmts/Exprs
209   // have been written. We want it last because we will not read it back when
210   // retrieving it from the AST, we'll just lazily set the offset.
211   if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
212     Record.push_back(FD->doesThisDeclarationHaveABody());
213     if (FD->doesThisDeclarationHaveABody())
214       AddFunctionDefinition(FD);
215   }
216 }
217 
218 void ASTDeclWriter::VisitDecl(Decl *D) {
219   Writer.AddDeclRef(cast_or_null<Decl>(D->getDeclContext()), Record);
220   Writer.AddDeclRef(cast_or_null<Decl>(D->getLexicalDeclContext()), Record);
221   Record.push_back(D->isInvalidDecl());
222   Record.push_back(D->hasAttrs());
223   if (D->hasAttrs())
224     Writer.WriteAttributes(llvm::makeArrayRef(D->getAttrs().begin(),
225                                               D->getAttrs().size()), Record);
226   Record.push_back(D->isImplicit());
227   Record.push_back(D->isUsed(false));
228   Record.push_back(D->isReferenced());
229   Record.push_back(D->isTopLevelDeclInObjCContainer());
230   Record.push_back(D->getAccess());
231   Record.push_back(D->isModulePrivate());
232   Record.push_back(Writer.inferSubmoduleIDFromLocation(D->getLocation()));
233 
234   // If this declaration injected a name into a context different from its
235   // lexical context, and that context is an imported namespace, we need to
236   // update its visible declarations to include this name.
237   //
238   // This happens when we instantiate a class with a friend declaration or a
239   // function with a local extern declaration, for instance.
240   if (D->isOutOfLine()) {
241     auto *DC = D->getDeclContext();
242     while (auto *NS = dyn_cast<NamespaceDecl>(DC->getRedeclContext())) {
243       if (!NS->isFromASTFile())
244         break;
245       Writer.UpdatedDeclContexts.insert(NS->getPrimaryContext());
246       if (!NS->isInlineNamespace())
247         break;
248       DC = NS->getParent();
249     }
250   }
251 }
252 
253 void ASTDeclWriter::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
254   llvm_unreachable("Translation units aren't directly serialized");
255 }
256 
257 void ASTDeclWriter::VisitNamedDecl(NamedDecl *D) {
258   VisitDecl(D);
259   Writer.AddDeclarationName(D->getDeclName(), Record);
260   Record.push_back(needsAnonymousDeclarationNumber(D)
261                        ? Writer.getAnonymousDeclarationNumber(D)
262                        : 0);
263 }
264 
265 void ASTDeclWriter::VisitTypeDecl(TypeDecl *D) {
266   VisitNamedDecl(D);
267   Writer.AddSourceLocation(D->getLocStart(), Record);
268   Writer.AddTypeRef(QualType(D->getTypeForDecl(), 0), Record);
269 }
270 
271 void ASTDeclWriter::VisitTypedefNameDecl(TypedefNameDecl *D) {
272   VisitRedeclarable(D);
273   VisitTypeDecl(D);
274   Writer.AddTypeSourceInfo(D->getTypeSourceInfo(), Record);
275   Record.push_back(D->isModed());
276   if (D->isModed())
277     Writer.AddTypeRef(D->getUnderlyingType(), Record);
278 }
279 
280 void ASTDeclWriter::VisitTypedefDecl(TypedefDecl *D) {
281   VisitTypedefNameDecl(D);
282   if (!D->hasAttrs() &&
283       !D->isImplicit() &&
284       D->getFirstDecl() == D->getMostRecentDecl() &&
285       !D->isInvalidDecl() &&
286       !D->isTopLevelDeclInObjCContainer() &&
287       !D->isModulePrivate() &&
288       !needsAnonymousDeclarationNumber(D) &&
289       D->getDeclName().getNameKind() == DeclarationName::Identifier)
290     AbbrevToUse = Writer.getDeclTypedefAbbrev();
291 
292   Code = serialization::DECL_TYPEDEF;
293 }
294 
295 void ASTDeclWriter::VisitTypeAliasDecl(TypeAliasDecl *D) {
296   VisitTypedefNameDecl(D);
297   Writer.AddDeclRef(D->getDescribedAliasTemplate(), Record);
298   Code = serialization::DECL_TYPEALIAS;
299 }
300 
301 void ASTDeclWriter::VisitTagDecl(TagDecl *D) {
302   VisitRedeclarable(D);
303   VisitTypeDecl(D);
304   Record.push_back(D->getIdentifierNamespace());
305   Record.push_back((unsigned)D->getTagKind()); // FIXME: stable encoding
306   if (!isa<CXXRecordDecl>(D))
307     Record.push_back(D->isCompleteDefinition());
308   Record.push_back(D->isEmbeddedInDeclarator());
309   Record.push_back(D->isFreeStanding());
310   Record.push_back(D->isCompleteDefinitionRequired());
311   Writer.AddSourceLocation(D->getRBraceLoc(), Record);
312 
313   if (D->hasExtInfo()) {
314     Record.push_back(1);
315     Writer.AddQualifierInfo(*D->getExtInfo(), Record);
316   } else if (auto *TD = D->getTypedefNameForAnonDecl()) {
317     Record.push_back(2);
318     Writer.AddDeclRef(TD, Record);
319     Writer.AddIdentifierRef(TD->getDeclName().getAsIdentifierInfo(), Record);
320   } else if (auto *DD = D->getDeclaratorForAnonDecl()) {
321     Record.push_back(3);
322     Writer.AddDeclRef(DD, Record);
323   } else {
324     Record.push_back(0);
325   }
326 }
327 
328 void ASTDeclWriter::VisitEnumDecl(EnumDecl *D) {
329   VisitTagDecl(D);
330   Writer.AddTypeSourceInfo(D->getIntegerTypeSourceInfo(), Record);
331   if (!D->getIntegerTypeSourceInfo())
332     Writer.AddTypeRef(D->getIntegerType(), Record);
333   Writer.AddTypeRef(D->getPromotionType(), Record);
334   Record.push_back(D->getNumPositiveBits());
335   Record.push_back(D->getNumNegativeBits());
336   Record.push_back(D->isScoped());
337   Record.push_back(D->isScopedUsingClassTag());
338   Record.push_back(D->isFixed());
339   if (MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo()) {
340     Writer.AddDeclRef(MemberInfo->getInstantiatedFrom(), Record);
341     Record.push_back(MemberInfo->getTemplateSpecializationKind());
342     Writer.AddSourceLocation(MemberInfo->getPointOfInstantiation(), Record);
343   } else {
344     Writer.AddDeclRef(nullptr, Record);
345   }
346 
347   if (!D->hasAttrs() &&
348       !D->isImplicit() &&
349       !D->isUsed(false) &&
350       !D->hasExtInfo() &&
351       !D->getTypedefNameForAnonDecl() &&
352       !D->getDeclaratorForAnonDecl() &&
353       D->getFirstDecl() == D->getMostRecentDecl() &&
354       !D->isInvalidDecl() &&
355       !D->isReferenced() &&
356       !D->isTopLevelDeclInObjCContainer() &&
357       D->getAccess() == AS_none &&
358       !D->isModulePrivate() &&
359       !CXXRecordDecl::classofKind(D->getKind()) &&
360       !D->getIntegerTypeSourceInfo() &&
361       !D->getMemberSpecializationInfo() &&
362       !needsAnonymousDeclarationNumber(D) &&
363       D->getDeclName().getNameKind() == DeclarationName::Identifier)
364     AbbrevToUse = Writer.getDeclEnumAbbrev();
365 
366   Code = serialization::DECL_ENUM;
367 }
368 
369 void ASTDeclWriter::VisitRecordDecl(RecordDecl *D) {
370   VisitTagDecl(D);
371   Record.push_back(D->hasFlexibleArrayMember());
372   Record.push_back(D->isAnonymousStructOrUnion());
373   Record.push_back(D->hasObjectMember());
374   Record.push_back(D->hasVolatileMember());
375 
376   if (!D->hasAttrs() &&
377       !D->isImplicit() &&
378       !D->isUsed(false) &&
379       !D->hasExtInfo() &&
380       !D->getTypedefNameForAnonDecl() &&
381       !D->getDeclaratorForAnonDecl() &&
382       D->getFirstDecl() == D->getMostRecentDecl() &&
383       !D->isInvalidDecl() &&
384       !D->isReferenced() &&
385       !D->isTopLevelDeclInObjCContainer() &&
386       D->getAccess() == AS_none &&
387       !D->isModulePrivate() &&
388       !CXXRecordDecl::classofKind(D->getKind()) &&
389       !needsAnonymousDeclarationNumber(D) &&
390       D->getDeclName().getNameKind() == DeclarationName::Identifier)
391     AbbrevToUse = Writer.getDeclRecordAbbrev();
392 
393   Code = serialization::DECL_RECORD;
394 }
395 
396 void ASTDeclWriter::VisitValueDecl(ValueDecl *D) {
397   VisitNamedDecl(D);
398   Writer.AddTypeRef(D->getType(), Record);
399 }
400 
401 void ASTDeclWriter::VisitEnumConstantDecl(EnumConstantDecl *D) {
402   VisitValueDecl(D);
403   Record.push_back(D->getInitExpr()? 1 : 0);
404   if (D->getInitExpr())
405     Writer.AddStmt(D->getInitExpr());
406   Writer.AddAPSInt(D->getInitVal(), Record);
407 
408   Code = serialization::DECL_ENUM_CONSTANT;
409 }
410 
411 void ASTDeclWriter::VisitDeclaratorDecl(DeclaratorDecl *D) {
412   VisitValueDecl(D);
413   Writer.AddSourceLocation(D->getInnerLocStart(), Record);
414   Record.push_back(D->hasExtInfo());
415   if (D->hasExtInfo())
416     Writer.AddQualifierInfo(*D->getExtInfo(), Record);
417 }
418 
419 void ASTDeclWriter::VisitFunctionDecl(FunctionDecl *D) {
420   VisitRedeclarable(D);
421   VisitDeclaratorDecl(D);
422   Writer.AddDeclarationNameLoc(D->DNLoc, D->getDeclName(), Record);
423   Record.push_back(D->getIdentifierNamespace());
424 
425   // FunctionDecl's body is handled last at ASTWriterDecl::Visit,
426   // after everything else is written.
427 
428   Record.push_back((int)D->SClass); // FIXME: stable encoding
429   Record.push_back(D->IsInline);
430   Record.push_back(D->IsInlineSpecified);
431   Record.push_back(D->IsVirtualAsWritten);
432   Record.push_back(D->IsPure);
433   Record.push_back(D->HasInheritedPrototype);
434   Record.push_back(D->HasWrittenPrototype);
435   Record.push_back(D->IsDeleted);
436   Record.push_back(D->IsTrivial);
437   Record.push_back(D->IsDefaulted);
438   Record.push_back(D->IsExplicitlyDefaulted);
439   Record.push_back(D->HasImplicitReturnZero);
440   Record.push_back(D->IsConstexpr);
441   Record.push_back(D->HasSkippedBody);
442   Record.push_back(D->IsLateTemplateParsed);
443   Record.push_back(D->getLinkageInternal());
444   Writer.AddSourceLocation(D->getLocEnd(), Record);
445 
446   Record.push_back(D->getTemplatedKind());
447   switch (D->getTemplatedKind()) {
448   case FunctionDecl::TK_NonTemplate:
449     break;
450   case FunctionDecl::TK_FunctionTemplate:
451     Writer.AddDeclRef(D->getDescribedFunctionTemplate(), Record);
452     break;
453   case FunctionDecl::TK_MemberSpecialization: {
454     MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo();
455     Writer.AddDeclRef(MemberInfo->getInstantiatedFrom(), Record);
456     Record.push_back(MemberInfo->getTemplateSpecializationKind());
457     Writer.AddSourceLocation(MemberInfo->getPointOfInstantiation(), Record);
458     break;
459   }
460   case FunctionDecl::TK_FunctionTemplateSpecialization: {
461     FunctionTemplateSpecializationInfo *
462       FTSInfo = D->getTemplateSpecializationInfo();
463     Writer.AddDeclRef(FTSInfo->getTemplate(), Record);
464     Record.push_back(FTSInfo->getTemplateSpecializationKind());
465 
466     // Template arguments.
467     Writer.AddTemplateArgumentList(FTSInfo->TemplateArguments, Record);
468 
469     // Template args as written.
470     Record.push_back(FTSInfo->TemplateArgumentsAsWritten != nullptr);
471     if (FTSInfo->TemplateArgumentsAsWritten) {
472       Record.push_back(FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs);
473       for (int i=0, e = FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs;
474              i!=e; ++i)
475         Writer.AddTemplateArgumentLoc((*FTSInfo->TemplateArgumentsAsWritten)[i],
476                                       Record);
477       Writer.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->LAngleLoc,
478                                Record);
479       Writer.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->RAngleLoc,
480                                Record);
481     }
482 
483     Writer.AddSourceLocation(FTSInfo->getPointOfInstantiation(), Record);
484 
485     if (D->isCanonicalDecl()) {
486       // Write the template that contains the specializations set. We will
487       // add a FunctionTemplateSpecializationInfo to it when reading.
488       Writer.AddDeclRef(FTSInfo->getTemplate()->getCanonicalDecl(), Record);
489     }
490     break;
491   }
492   case FunctionDecl::TK_DependentFunctionTemplateSpecialization: {
493     DependentFunctionTemplateSpecializationInfo *
494       DFTSInfo = D->getDependentSpecializationInfo();
495 
496     // Templates.
497     Record.push_back(DFTSInfo->getNumTemplates());
498     for (int i=0, e = DFTSInfo->getNumTemplates(); i != e; ++i)
499       Writer.AddDeclRef(DFTSInfo->getTemplate(i), Record);
500 
501     // Templates args.
502     Record.push_back(DFTSInfo->getNumTemplateArgs());
503     for (int i=0, e = DFTSInfo->getNumTemplateArgs(); i != e; ++i)
504       Writer.AddTemplateArgumentLoc(DFTSInfo->getTemplateArg(i), Record);
505     Writer.AddSourceLocation(DFTSInfo->getLAngleLoc(), Record);
506     Writer.AddSourceLocation(DFTSInfo->getRAngleLoc(), Record);
507     break;
508   }
509   }
510 
511   Record.push_back(D->param_size());
512   for (auto P : D->params())
513     Writer.AddDeclRef(P, Record);
514   Code = serialization::DECL_FUNCTION;
515 }
516 
517 void ASTDeclWriter::VisitObjCMethodDecl(ObjCMethodDecl *D) {
518   VisitNamedDecl(D);
519   // FIXME: convert to LazyStmtPtr?
520   // Unlike C/C++, method bodies will never be in header files.
521   bool HasBodyStuff = D->getBody() != nullptr     ||
522                       D->getSelfDecl() != nullptr || D->getCmdDecl() != nullptr;
523   Record.push_back(HasBodyStuff);
524   if (HasBodyStuff) {
525     Writer.AddStmt(D->getBody());
526     Writer.AddDeclRef(D->getSelfDecl(), Record);
527     Writer.AddDeclRef(D->getCmdDecl(), Record);
528   }
529   Record.push_back(D->isInstanceMethod());
530   Record.push_back(D->isVariadic());
531   Record.push_back(D->isPropertyAccessor());
532   Record.push_back(D->isDefined());
533   Record.push_back(D->IsOverriding);
534   Record.push_back(D->HasSkippedBody);
535 
536   Record.push_back(D->IsRedeclaration);
537   Record.push_back(D->HasRedeclaration);
538   if (D->HasRedeclaration) {
539     assert(Context.getObjCMethodRedeclaration(D));
540     Writer.AddDeclRef(Context.getObjCMethodRedeclaration(D), Record);
541   }
542 
543   // FIXME: stable encoding for @required/@optional
544   Record.push_back(D->getImplementationControl());
545   // FIXME: stable encoding for in/out/inout/bycopy/byref/oneway
546   Record.push_back(D->getObjCDeclQualifier());
547   Record.push_back(D->hasRelatedResultType());
548   Writer.AddTypeRef(D->getReturnType(), Record);
549   Writer.AddTypeSourceInfo(D->getReturnTypeSourceInfo(), Record);
550   Writer.AddSourceLocation(D->getLocEnd(), Record);
551   Record.push_back(D->param_size());
552   for (const auto *P : D->params())
553     Writer.AddDeclRef(P, Record);
554 
555   Record.push_back(D->SelLocsKind);
556   unsigned NumStoredSelLocs = D->getNumStoredSelLocs();
557   SourceLocation *SelLocs = D->getStoredSelLocs();
558   Record.push_back(NumStoredSelLocs);
559   for (unsigned i = 0; i != NumStoredSelLocs; ++i)
560     Writer.AddSourceLocation(SelLocs[i], Record);
561 
562   Code = serialization::DECL_OBJC_METHOD;
563 }
564 
565 void ASTDeclWriter::VisitObjCContainerDecl(ObjCContainerDecl *D) {
566   VisitNamedDecl(D);
567   Writer.AddSourceLocation(D->getAtStartLoc(), Record);
568   Writer.AddSourceRange(D->getAtEndRange(), Record);
569   // Abstract class (no need to define a stable serialization::DECL code).
570 }
571 
572 void ASTDeclWriter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
573   VisitRedeclarable(D);
574   VisitObjCContainerDecl(D);
575   Writer.AddTypeRef(QualType(D->getTypeForDecl(), 0), Record);
576 
577   Record.push_back(D->isThisDeclarationADefinition());
578   if (D->isThisDeclarationADefinition()) {
579     // Write the DefinitionData
580     ObjCInterfaceDecl::DefinitionData &Data = D->data();
581 
582     Writer.AddDeclRef(D->getSuperClass(), Record);
583     Writer.AddSourceLocation(D->getSuperClassLoc(), Record);
584     Writer.AddSourceLocation(D->getEndOfDefinitionLoc(), Record);
585     Record.push_back(Data.HasDesignatedInitializers);
586 
587     // Write out the protocols that are directly referenced by the @interface.
588     Record.push_back(Data.ReferencedProtocols.size());
589     for (const auto *P : D->protocols())
590       Writer.AddDeclRef(P, Record);
591     for (const auto &PL : D->protocol_locs())
592       Writer.AddSourceLocation(PL, Record);
593 
594     // Write out the protocols that are transitively referenced.
595     Record.push_back(Data.AllReferencedProtocols.size());
596     for (ObjCList<ObjCProtocolDecl>::iterator
597               P = Data.AllReferencedProtocols.begin(),
598            PEnd = Data.AllReferencedProtocols.end();
599          P != PEnd; ++P)
600       Writer.AddDeclRef(*P, Record);
601 
602 
603     if (ObjCCategoryDecl *Cat = D->getCategoryListRaw()) {
604       // Ensure that we write out the set of categories for this class.
605       Writer.ObjCClassesWithCategories.insert(D);
606 
607       // Make sure that the categories get serialized.
608       for (; Cat; Cat = Cat->getNextClassCategoryRaw())
609         (void)Writer.GetDeclRef(Cat);
610     }
611   }
612 
613   Code = serialization::DECL_OBJC_INTERFACE;
614 }
615 
616 void ASTDeclWriter::VisitObjCIvarDecl(ObjCIvarDecl *D) {
617   VisitFieldDecl(D);
618   // FIXME: stable encoding for @public/@private/@protected/@package
619   Record.push_back(D->getAccessControl());
620   Record.push_back(D->getSynthesize());
621 
622   if (!D->hasAttrs() &&
623       !D->isImplicit() &&
624       !D->isUsed(false) &&
625       !D->isInvalidDecl() &&
626       !D->isReferenced() &&
627       !D->isModulePrivate() &&
628       !D->getBitWidth() &&
629       !D->hasExtInfo() &&
630       D->getDeclName())
631     AbbrevToUse = Writer.getDeclObjCIvarAbbrev();
632 
633   Code = serialization::DECL_OBJC_IVAR;
634 }
635 
636 void ASTDeclWriter::VisitObjCProtocolDecl(ObjCProtocolDecl *D) {
637   VisitRedeclarable(D);
638   VisitObjCContainerDecl(D);
639 
640   Record.push_back(D->isThisDeclarationADefinition());
641   if (D->isThisDeclarationADefinition()) {
642     Record.push_back(D->protocol_size());
643     for (const auto *I : D->protocols())
644       Writer.AddDeclRef(I, Record);
645     for (const auto &PL : D->protocol_locs())
646       Writer.AddSourceLocation(PL, Record);
647   }
648 
649   Code = serialization::DECL_OBJC_PROTOCOL;
650 }
651 
652 void ASTDeclWriter::VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D) {
653   VisitFieldDecl(D);
654   Code = serialization::DECL_OBJC_AT_DEFS_FIELD;
655 }
656 
657 void ASTDeclWriter::VisitObjCCategoryDecl(ObjCCategoryDecl *D) {
658   VisitObjCContainerDecl(D);
659   Writer.AddSourceLocation(D->getCategoryNameLoc(), Record);
660   Writer.AddSourceLocation(D->getIvarLBraceLoc(), Record);
661   Writer.AddSourceLocation(D->getIvarRBraceLoc(), Record);
662   Writer.AddDeclRef(D->getClassInterface(), Record);
663   Record.push_back(D->protocol_size());
664   for (const auto *I : D->protocols())
665     Writer.AddDeclRef(I, Record);
666   for (const auto &PL : D->protocol_locs())
667     Writer.AddSourceLocation(PL, Record);
668   Code = serialization::DECL_OBJC_CATEGORY;
669 }
670 
671 void ASTDeclWriter::VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D) {
672   VisitNamedDecl(D);
673   Writer.AddDeclRef(D->getClassInterface(), Record);
674   Code = serialization::DECL_OBJC_COMPATIBLE_ALIAS;
675 }
676 
677 void ASTDeclWriter::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
678   VisitNamedDecl(D);
679   Writer.AddSourceLocation(D->getAtLoc(), Record);
680   Writer.AddSourceLocation(D->getLParenLoc(), Record);
681   Writer.AddTypeSourceInfo(D->getTypeSourceInfo(), Record);
682   // FIXME: stable encoding
683   Record.push_back((unsigned)D->getPropertyAttributes());
684   Record.push_back((unsigned)D->getPropertyAttributesAsWritten());
685   // FIXME: stable encoding
686   Record.push_back((unsigned)D->getPropertyImplementation());
687   Writer.AddDeclarationName(D->getGetterName(), Record);
688   Writer.AddDeclarationName(D->getSetterName(), Record);
689   Writer.AddDeclRef(D->getGetterMethodDecl(), Record);
690   Writer.AddDeclRef(D->getSetterMethodDecl(), Record);
691   Writer.AddDeclRef(D->getPropertyIvarDecl(), Record);
692   Code = serialization::DECL_OBJC_PROPERTY;
693 }
694 
695 void ASTDeclWriter::VisitObjCImplDecl(ObjCImplDecl *D) {
696   VisitObjCContainerDecl(D);
697   Writer.AddDeclRef(D->getClassInterface(), Record);
698   // Abstract class (no need to define a stable serialization::DECL code).
699 }
700 
701 void ASTDeclWriter::VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D) {
702   VisitObjCImplDecl(D);
703   Writer.AddIdentifierRef(D->getIdentifier(), Record);
704   Writer.AddSourceLocation(D->getCategoryNameLoc(), Record);
705   Code = serialization::DECL_OBJC_CATEGORY_IMPL;
706 }
707 
708 void ASTDeclWriter::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
709   VisitObjCImplDecl(D);
710   Writer.AddDeclRef(D->getSuperClass(), Record);
711   Writer.AddSourceLocation(D->getSuperClassLoc(), Record);
712   Writer.AddSourceLocation(D->getIvarLBraceLoc(), Record);
713   Writer.AddSourceLocation(D->getIvarRBraceLoc(), Record);
714   Record.push_back(D->hasNonZeroConstructors());
715   Record.push_back(D->hasDestructors());
716   Record.push_back(D->NumIvarInitializers);
717   if (D->NumIvarInitializers)
718     Writer.AddCXXCtorInitializersRef(
719         llvm::makeArrayRef(D->init_begin(), D->init_end()), Record);
720   Code = serialization::DECL_OBJC_IMPLEMENTATION;
721 }
722 
723 void ASTDeclWriter::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
724   VisitDecl(D);
725   Writer.AddSourceLocation(D->getLocStart(), Record);
726   Writer.AddDeclRef(D->getPropertyDecl(), Record);
727   Writer.AddDeclRef(D->getPropertyIvarDecl(), Record);
728   Writer.AddSourceLocation(D->getPropertyIvarDeclLoc(), Record);
729   Writer.AddStmt(D->getGetterCXXConstructor());
730   Writer.AddStmt(D->getSetterCXXAssignment());
731   Code = serialization::DECL_OBJC_PROPERTY_IMPL;
732 }
733 
734 void ASTDeclWriter::VisitFieldDecl(FieldDecl *D) {
735   VisitDeclaratorDecl(D);
736   Record.push_back(D->isMutable());
737   if (D->InitStorage.getInt() == FieldDecl::ISK_BitWidthOrNothing &&
738       D->InitStorage.getPointer() == nullptr) {
739     Record.push_back(0);
740   } else if (D->InitStorage.getInt() == FieldDecl::ISK_CapturedVLAType) {
741     Record.push_back(D->InitStorage.getInt() + 1);
742     Writer.AddTypeRef(
743         QualType(static_cast<Type *>(D->InitStorage.getPointer()), 0),
744         Record);
745   } else {
746     Record.push_back(D->InitStorage.getInt() + 1);
747     Writer.AddStmt(static_cast<Expr *>(D->InitStorage.getPointer()));
748   }
749   if (!D->getDeclName())
750     Writer.AddDeclRef(Context.getInstantiatedFromUnnamedFieldDecl(D), Record);
751 
752   if (!D->hasAttrs() &&
753       !D->isImplicit() &&
754       !D->isUsed(false) &&
755       !D->isInvalidDecl() &&
756       !D->isReferenced() &&
757       !D->isTopLevelDeclInObjCContainer() &&
758       !D->isModulePrivate() &&
759       !D->getBitWidth() &&
760       !D->hasInClassInitializer() &&
761       !D->hasExtInfo() &&
762       !ObjCIvarDecl::classofKind(D->getKind()) &&
763       !ObjCAtDefsFieldDecl::classofKind(D->getKind()) &&
764       D->getDeclName())
765     AbbrevToUse = Writer.getDeclFieldAbbrev();
766 
767   Code = serialization::DECL_FIELD;
768 }
769 
770 void ASTDeclWriter::VisitMSPropertyDecl(MSPropertyDecl *D) {
771   VisitDeclaratorDecl(D);
772   Writer.AddIdentifierRef(D->getGetterId(), Record);
773   Writer.AddIdentifierRef(D->getSetterId(), Record);
774   Code = serialization::DECL_MS_PROPERTY;
775 }
776 
777 void ASTDeclWriter::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
778   VisitValueDecl(D);
779   Record.push_back(D->getChainingSize());
780 
781   for (const auto *P : D->chain())
782     Writer.AddDeclRef(P, Record);
783   Code = serialization::DECL_INDIRECTFIELD;
784 }
785 
786 void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
787   VisitRedeclarable(D);
788   VisitDeclaratorDecl(D);
789   Record.push_back(D->getStorageClass());
790   Record.push_back(D->getTSCSpec());
791   Record.push_back(D->getInitStyle());
792   if (!isa<ParmVarDecl>(D)) {
793     Record.push_back(D->isExceptionVariable());
794     Record.push_back(D->isNRVOVariable());
795     Record.push_back(D->isCXXForRangeDecl());
796     Record.push_back(D->isARCPseudoStrong());
797     Record.push_back(D->isConstexpr());
798     Record.push_back(D->isInitCapture());
799     Record.push_back(D->isPreviousDeclInSameBlockScope());
800   }
801   Record.push_back(D->getLinkageInternal());
802 
803   if (D->getInit()) {
804     Record.push_back(!D->isInitKnownICE() ? 1 : (D->isInitICE() ? 3 : 2));
805     Writer.AddStmt(D->getInit());
806   } else {
807     Record.push_back(0);
808   }
809 
810   enum {
811     VarNotTemplate = 0, VarTemplate, StaticDataMemberSpecialization
812   };
813   if (VarTemplateDecl *TemplD = D->getDescribedVarTemplate()) {
814     Record.push_back(VarTemplate);
815     Writer.AddDeclRef(TemplD, Record);
816   } else if (MemberSpecializationInfo *SpecInfo
817                = D->getMemberSpecializationInfo()) {
818     Record.push_back(StaticDataMemberSpecialization);
819     Writer.AddDeclRef(SpecInfo->getInstantiatedFrom(), Record);
820     Record.push_back(SpecInfo->getTemplateSpecializationKind());
821     Writer.AddSourceLocation(SpecInfo->getPointOfInstantiation(), Record);
822   } else {
823     Record.push_back(VarNotTemplate);
824   }
825 
826   if (!D->hasAttrs() &&
827       !D->isImplicit() &&
828       !D->isUsed(false) &&
829       !D->isInvalidDecl() &&
830       !D->isReferenced() &&
831       !D->isTopLevelDeclInObjCContainer() &&
832       D->getAccess() == AS_none &&
833       !D->isModulePrivate() &&
834       !needsAnonymousDeclarationNumber(D) &&
835       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
836       !D->hasExtInfo() &&
837       D->getFirstDecl() == D->getMostRecentDecl() &&
838       D->getInitStyle() == VarDecl::CInit &&
839       D->getInit() == nullptr &&
840       !isa<ParmVarDecl>(D) &&
841       !isa<VarTemplateSpecializationDecl>(D) &&
842       !D->isConstexpr() &&
843       !D->isInitCapture() &&
844       !D->isPreviousDeclInSameBlockScope() &&
845       !D->getMemberSpecializationInfo())
846     AbbrevToUse = Writer.getDeclVarAbbrev();
847 
848   Code = serialization::DECL_VAR;
849 }
850 
851 void ASTDeclWriter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
852   VisitVarDecl(D);
853   Code = serialization::DECL_IMPLICIT_PARAM;
854 }
855 
856 void ASTDeclWriter::VisitParmVarDecl(ParmVarDecl *D) {
857   VisitVarDecl(D);
858   Record.push_back(D->isObjCMethodParameter());
859   Record.push_back(D->getFunctionScopeDepth());
860   Record.push_back(D->getFunctionScopeIndex());
861   Record.push_back(D->getObjCDeclQualifier()); // FIXME: stable encoding
862   Record.push_back(D->isKNRPromoted());
863   Record.push_back(D->hasInheritedDefaultArg());
864   Record.push_back(D->hasUninstantiatedDefaultArg());
865   if (D->hasUninstantiatedDefaultArg())
866     Writer.AddStmt(D->getUninstantiatedDefaultArg());
867   Code = serialization::DECL_PARM_VAR;
868 
869   assert(!D->isARCPseudoStrong()); // can be true of ImplicitParamDecl
870 
871   // If the assumptions about the DECL_PARM_VAR abbrev are true, use it.  Here
872   // we dynamically check for the properties that we optimize for, but don't
873   // know are true of all PARM_VAR_DECLs.
874   if (!D->hasAttrs() &&
875       !D->hasExtInfo() &&
876       !D->isImplicit() &&
877       !D->isUsed(false) &&
878       !D->isInvalidDecl() &&
879       !D->isReferenced() &&
880       D->getAccess() == AS_none &&
881       !D->isModulePrivate() &&
882       D->getStorageClass() == 0 &&
883       D->getInitStyle() == VarDecl::CInit && // Can params have anything else?
884       D->getFunctionScopeDepth() == 0 &&
885       D->getObjCDeclQualifier() == 0 &&
886       !D->isKNRPromoted() &&
887       !D->hasInheritedDefaultArg() &&
888       D->getInit() == nullptr &&
889       !D->hasUninstantiatedDefaultArg())  // No default expr.
890     AbbrevToUse = Writer.getDeclParmVarAbbrev();
891 
892   // Check things we know are true of *every* PARM_VAR_DECL, which is more than
893   // just us assuming it.
894   assert(!D->getTSCSpec() && "PARM_VAR_DECL can't use TLS");
895   assert(D->getAccess() == AS_none && "PARM_VAR_DECL can't be public/private");
896   assert(!D->isExceptionVariable() && "PARM_VAR_DECL can't be exception var");
897   assert(D->getPreviousDecl() == nullptr && "PARM_VAR_DECL can't be redecl");
898   assert(!D->isStaticDataMember() &&
899          "PARM_VAR_DECL can't be static data member");
900 }
901 
902 void ASTDeclWriter::VisitFileScopeAsmDecl(FileScopeAsmDecl *D) {
903   VisitDecl(D);
904   Writer.AddStmt(D->getAsmString());
905   Writer.AddSourceLocation(D->getRParenLoc(), Record);
906   Code = serialization::DECL_FILE_SCOPE_ASM;
907 }
908 
909 void ASTDeclWriter::VisitEmptyDecl(EmptyDecl *D) {
910   VisitDecl(D);
911   Code = serialization::DECL_EMPTY;
912 }
913 
914 void ASTDeclWriter::VisitBlockDecl(BlockDecl *D) {
915   VisitDecl(D);
916   Writer.AddStmt(D->getBody());
917   Writer.AddTypeSourceInfo(D->getSignatureAsWritten(), Record);
918   Record.push_back(D->param_size());
919   for (FunctionDecl::param_iterator P = D->param_begin(), PEnd = D->param_end();
920        P != PEnd; ++P)
921     Writer.AddDeclRef(*P, Record);
922   Record.push_back(D->isVariadic());
923   Record.push_back(D->blockMissingReturnType());
924   Record.push_back(D->isConversionFromLambda());
925   Record.push_back(D->capturesCXXThis());
926   Record.push_back(D->getNumCaptures());
927   for (const auto &capture : D->captures()) {
928     Writer.AddDeclRef(capture.getVariable(), Record);
929 
930     unsigned flags = 0;
931     if (capture.isByRef()) flags |= 1;
932     if (capture.isNested()) flags |= 2;
933     if (capture.hasCopyExpr()) flags |= 4;
934     Record.push_back(flags);
935 
936     if (capture.hasCopyExpr()) Writer.AddStmt(capture.getCopyExpr());
937   }
938 
939   Code = serialization::DECL_BLOCK;
940 }
941 
942 void ASTDeclWriter::VisitCapturedDecl(CapturedDecl *CD) {
943   Record.push_back(CD->getNumParams());
944   VisitDecl(CD);
945   Record.push_back(CD->getContextParamPosition());
946   Record.push_back(CD->isNothrow() ? 1 : 0);
947   // Body is stored by VisitCapturedStmt.
948   for (unsigned I = 0; I < CD->getNumParams(); ++I)
949     Writer.AddDeclRef(CD->getParam(I), Record);
950   Code = serialization::DECL_CAPTURED;
951 }
952 
953 void ASTDeclWriter::VisitLinkageSpecDecl(LinkageSpecDecl *D) {
954   VisitDecl(D);
955   Record.push_back(D->getLanguage());
956   Writer.AddSourceLocation(D->getExternLoc(), Record);
957   Writer.AddSourceLocation(D->getRBraceLoc(), Record);
958   Code = serialization::DECL_LINKAGE_SPEC;
959 }
960 
961 void ASTDeclWriter::VisitLabelDecl(LabelDecl *D) {
962   VisitNamedDecl(D);
963   Writer.AddSourceLocation(D->getLocStart(), Record);
964   Code = serialization::DECL_LABEL;
965 }
966 
967 
968 void ASTDeclWriter::VisitNamespaceDecl(NamespaceDecl *D) {
969   VisitRedeclarable(D);
970   VisitNamedDecl(D);
971   Record.push_back(D->isInline());
972   Writer.AddSourceLocation(D->getLocStart(), Record);
973   Writer.AddSourceLocation(D->getRBraceLoc(), Record);
974 
975   if (D->isOriginalNamespace())
976     Writer.AddDeclRef(D->getAnonymousNamespace(), Record);
977   Code = serialization::DECL_NAMESPACE;
978 
979   if (Writer.hasChain() && !D->isOriginalNamespace() &&
980       D->getOriginalNamespace()->isFromASTFile()) {
981     NamespaceDecl *NS = D->getOriginalNamespace();
982     Writer.UpdatedDeclContexts.insert(NS);
983 
984     // Make sure all visible decls are written. They will be recorded later. We
985     // do this using a side data structure so we can sort the names into
986     // a deterministic order.
987     StoredDeclsMap *Map = NS->buildLookup();
988     SmallVector<std::pair<DeclarationName, DeclContext::lookup_result>, 16>
989         LookupResults;
990     LookupResults.reserve(Map->size());
991     for (auto &Entry : *Map)
992       LookupResults.push_back(
993           std::make_pair(Entry.first, Entry.second.getLookupResult()));
994 
995     std::sort(LookupResults.begin(), LookupResults.end(), llvm::less_first());
996     for (auto &NameAndResult : LookupResults) {
997       DeclarationName Name = NameAndResult.first;
998       DeclContext::lookup_result Result = NameAndResult.second;
999       if (Name.getNameKind() == DeclarationName::CXXConstructorName ||
1000           Name.getNameKind() == DeclarationName::CXXConversionFunctionName) {
1001         // We have to work around a name lookup bug here where negative lookup
1002         // results for these names get cached in namespace lookup tables.
1003         assert(Result.empty() && "Cannot have a constructor or conversion "
1004                                  "function name in a namespace!");
1005         continue;
1006       }
1007 
1008       for (NamedDecl *ND : Result)
1009         Writer.GetDeclRef(ND);
1010     }
1011   }
1012 
1013   if (Writer.hasChain() && D->isAnonymousNamespace() &&
1014       D == D->getMostRecentDecl()) {
1015     // This is a most recent reopening of the anonymous namespace. If its parent
1016     // is in a previous PCH (or is the TU), mark that parent for update, because
1017     // the original namespace always points to the latest re-opening of its
1018     // anonymous namespace.
1019     Decl *Parent = cast<Decl>(
1020         D->getParent()->getRedeclContext()->getPrimaryContext());
1021     if (Parent->isFromASTFile() || isa<TranslationUnitDecl>(Parent)) {
1022       Writer.DeclUpdates[Parent].push_back(
1023           ASTWriter::DeclUpdate(UPD_CXX_ADDED_ANONYMOUS_NAMESPACE, D));
1024     }
1025   }
1026 }
1027 
1028 void ASTDeclWriter::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
1029   VisitRedeclarable(D);
1030   VisitNamedDecl(D);
1031   Writer.AddSourceLocation(D->getNamespaceLoc(), Record);
1032   Writer.AddSourceLocation(D->getTargetNameLoc(), Record);
1033   Writer.AddNestedNameSpecifierLoc(D->getQualifierLoc(), Record);
1034   Writer.AddDeclRef(D->getNamespace(), Record);
1035   Code = serialization::DECL_NAMESPACE_ALIAS;
1036 }
1037 
1038 void ASTDeclWriter::VisitUsingDecl(UsingDecl *D) {
1039   VisitNamedDecl(D);
1040   Writer.AddSourceLocation(D->getUsingLoc(), Record);
1041   Writer.AddNestedNameSpecifierLoc(D->getQualifierLoc(), Record);
1042   Writer.AddDeclarationNameLoc(D->DNLoc, D->getDeclName(), Record);
1043   Writer.AddDeclRef(D->FirstUsingShadow.getPointer(), Record);
1044   Record.push_back(D->hasTypename());
1045   Writer.AddDeclRef(Context.getInstantiatedFromUsingDecl(D), Record);
1046   Code = serialization::DECL_USING;
1047 }
1048 
1049 void ASTDeclWriter::VisitUsingShadowDecl(UsingShadowDecl *D) {
1050   VisitRedeclarable(D);
1051   VisitNamedDecl(D);
1052   Writer.AddDeclRef(D->getTargetDecl(), Record);
1053   Writer.AddDeclRef(D->UsingOrNextShadow, Record);
1054   Writer.AddDeclRef(Context.getInstantiatedFromUsingShadowDecl(D), Record);
1055   Code = serialization::DECL_USING_SHADOW;
1056 }
1057 
1058 void ASTDeclWriter::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1059   VisitNamedDecl(D);
1060   Writer.AddSourceLocation(D->getUsingLoc(), Record);
1061   Writer.AddSourceLocation(D->getNamespaceKeyLocation(), Record);
1062   Writer.AddNestedNameSpecifierLoc(D->getQualifierLoc(), Record);
1063   Writer.AddDeclRef(D->getNominatedNamespace(), Record);
1064   Writer.AddDeclRef(dyn_cast<Decl>(D->getCommonAncestor()), Record);
1065   Code = serialization::DECL_USING_DIRECTIVE;
1066 }
1067 
1068 void ASTDeclWriter::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1069   VisitValueDecl(D);
1070   Writer.AddSourceLocation(D->getUsingLoc(), Record);
1071   Writer.AddNestedNameSpecifierLoc(D->getQualifierLoc(), Record);
1072   Writer.AddDeclarationNameLoc(D->DNLoc, D->getDeclName(), Record);
1073   Code = serialization::DECL_UNRESOLVED_USING_VALUE;
1074 }
1075 
1076 void ASTDeclWriter::VisitUnresolvedUsingTypenameDecl(
1077                                                UnresolvedUsingTypenameDecl *D) {
1078   VisitTypeDecl(D);
1079   Writer.AddSourceLocation(D->getTypenameLoc(), Record);
1080   Writer.AddNestedNameSpecifierLoc(D->getQualifierLoc(), Record);
1081   Code = serialization::DECL_UNRESOLVED_USING_TYPENAME;
1082 }
1083 
1084 void ASTDeclWriter::VisitCXXRecordDecl(CXXRecordDecl *D) {
1085   VisitRecordDecl(D);
1086 
1087   enum {
1088     CXXRecNotTemplate = 0, CXXRecTemplate, CXXRecMemberSpecialization
1089   };
1090   if (ClassTemplateDecl *TemplD = D->getDescribedClassTemplate()) {
1091     Record.push_back(CXXRecTemplate);
1092     Writer.AddDeclRef(TemplD, Record);
1093   } else if (MemberSpecializationInfo *MSInfo
1094                = D->getMemberSpecializationInfo()) {
1095     Record.push_back(CXXRecMemberSpecialization);
1096     Writer.AddDeclRef(MSInfo->getInstantiatedFrom(), Record);
1097     Record.push_back(MSInfo->getTemplateSpecializationKind());
1098     Writer.AddSourceLocation(MSInfo->getPointOfInstantiation(), Record);
1099   } else {
1100     Record.push_back(CXXRecNotTemplate);
1101   }
1102 
1103   Record.push_back(D->isThisDeclarationADefinition());
1104   if (D->isThisDeclarationADefinition())
1105     Writer.AddCXXDefinitionData(D, Record);
1106 
1107   // Store (what we currently believe to be) the key function to avoid
1108   // deserializing every method so we can compute it.
1109   if (D->IsCompleteDefinition)
1110     Writer.AddDeclRef(Context.getCurrentKeyFunction(D), Record);
1111 
1112   Code = serialization::DECL_CXX_RECORD;
1113 }
1114 
1115 void ASTDeclWriter::VisitCXXMethodDecl(CXXMethodDecl *D) {
1116   VisitFunctionDecl(D);
1117   if (D->isCanonicalDecl()) {
1118     Record.push_back(D->size_overridden_methods());
1119     for (CXXMethodDecl::method_iterator
1120            I = D->begin_overridden_methods(), E = D->end_overridden_methods();
1121            I != E; ++I)
1122       Writer.AddDeclRef(*I, Record);
1123   } else {
1124     // We only need to record overridden methods once for the canonical decl.
1125     Record.push_back(0);
1126   }
1127 
1128   if (D->getFirstDecl() == D->getMostRecentDecl() &&
1129       !D->isInvalidDecl() &&
1130       !D->hasAttrs() &&
1131       !D->isTopLevelDeclInObjCContainer() &&
1132       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1133       !D->hasExtInfo() &&
1134       !D->hasInheritedPrototype() &&
1135       D->hasWrittenPrototype())
1136     AbbrevToUse = Writer.getDeclCXXMethodAbbrev();
1137 
1138   Code = serialization::DECL_CXX_METHOD;
1139 }
1140 
1141 void ASTDeclWriter::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1142   VisitCXXMethodDecl(D);
1143 
1144   Writer.AddDeclRef(D->getInheritedConstructor(), Record);
1145   Record.push_back(D->IsExplicitSpecified);
1146 
1147   Code = serialization::DECL_CXX_CONSTRUCTOR;
1148 }
1149 
1150 void ASTDeclWriter::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1151   VisitCXXMethodDecl(D);
1152 
1153   Writer.AddDeclRef(D->getOperatorDelete(), Record);
1154 
1155   Code = serialization::DECL_CXX_DESTRUCTOR;
1156 }
1157 
1158 void ASTDeclWriter::VisitCXXConversionDecl(CXXConversionDecl *D) {
1159   VisitCXXMethodDecl(D);
1160   Record.push_back(D->IsExplicitSpecified);
1161   Code = serialization::DECL_CXX_CONVERSION;
1162 }
1163 
1164 void ASTDeclWriter::VisitImportDecl(ImportDecl *D) {
1165   VisitDecl(D);
1166   Record.push_back(Writer.getSubmoduleID(D->getImportedModule()));
1167   ArrayRef<SourceLocation> IdentifierLocs = D->getIdentifierLocs();
1168   Record.push_back(!IdentifierLocs.empty());
1169   if (IdentifierLocs.empty()) {
1170     Writer.AddSourceLocation(D->getLocEnd(), Record);
1171     Record.push_back(1);
1172   } else {
1173     for (unsigned I = 0, N = IdentifierLocs.size(); I != N; ++I)
1174       Writer.AddSourceLocation(IdentifierLocs[I], Record);
1175     Record.push_back(IdentifierLocs.size());
1176   }
1177   // Note: the number of source locations must always be the last element in
1178   // the record.
1179   Code = serialization::DECL_IMPORT;
1180 }
1181 
1182 void ASTDeclWriter::VisitAccessSpecDecl(AccessSpecDecl *D) {
1183   VisitDecl(D);
1184   Writer.AddSourceLocation(D->getColonLoc(), Record);
1185   Code = serialization::DECL_ACCESS_SPEC;
1186 }
1187 
1188 void ASTDeclWriter::VisitFriendDecl(FriendDecl *D) {
1189   // Record the number of friend type template parameter lists here
1190   // so as to simplify memory allocation during deserialization.
1191   Record.push_back(D->NumTPLists);
1192   VisitDecl(D);
1193   bool hasFriendDecl = D->Friend.is<NamedDecl*>();
1194   Record.push_back(hasFriendDecl);
1195   if (hasFriendDecl)
1196     Writer.AddDeclRef(D->getFriendDecl(), Record);
1197   else
1198     Writer.AddTypeSourceInfo(D->getFriendType(), Record);
1199   for (unsigned i = 0; i < D->NumTPLists; ++i)
1200     Writer.AddTemplateParameterList(D->getFriendTypeTemplateParameterList(i),
1201                                     Record);
1202   Writer.AddDeclRef(D->getNextFriend(), Record);
1203   Record.push_back(D->UnsupportedFriend);
1204   Writer.AddSourceLocation(D->FriendLoc, Record);
1205   Code = serialization::DECL_FRIEND;
1206 }
1207 
1208 void ASTDeclWriter::VisitFriendTemplateDecl(FriendTemplateDecl *D) {
1209   VisitDecl(D);
1210   Record.push_back(D->getNumTemplateParameters());
1211   for (unsigned i = 0, e = D->getNumTemplateParameters(); i != e; ++i)
1212     Writer.AddTemplateParameterList(D->getTemplateParameterList(i), Record);
1213   Record.push_back(D->getFriendDecl() != nullptr);
1214   if (D->getFriendDecl())
1215     Writer.AddDeclRef(D->getFriendDecl(), Record);
1216   else
1217     Writer.AddTypeSourceInfo(D->getFriendType(), Record);
1218   Writer.AddSourceLocation(D->getFriendLoc(), Record);
1219   Code = serialization::DECL_FRIEND_TEMPLATE;
1220 }
1221 
1222 void ASTDeclWriter::VisitTemplateDecl(TemplateDecl *D) {
1223   VisitNamedDecl(D);
1224 
1225   Writer.AddDeclRef(D->getTemplatedDecl(), Record);
1226   Writer.AddTemplateParameterList(D->getTemplateParameters(), Record);
1227 }
1228 
1229 void ASTDeclWriter::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
1230   VisitRedeclarable(D);
1231 
1232   // Emit data to initialize CommonOrPrev before VisitTemplateDecl so that
1233   // getCommonPtr() can be used while this is still initializing.
1234   if (D->isFirstDecl()) {
1235     // This declaration owns the 'common' pointer, so serialize that data now.
1236     Writer.AddDeclRef(D->getInstantiatedFromMemberTemplate(), Record);
1237     if (D->getInstantiatedFromMemberTemplate())
1238       Record.push_back(D->isMemberSpecialization());
1239   }
1240 
1241   VisitTemplateDecl(D);
1242   Record.push_back(D->getIdentifierNamespace());
1243 }
1244 
1245 void ASTDeclWriter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
1246   VisitRedeclarableTemplateDecl(D);
1247 
1248   if (D->isFirstDecl())
1249     AddTemplateSpecializations(D);
1250   Code = serialization::DECL_CLASS_TEMPLATE;
1251 }
1252 
1253 void ASTDeclWriter::VisitClassTemplateSpecializationDecl(
1254                                            ClassTemplateSpecializationDecl *D) {
1255   VisitCXXRecordDecl(D);
1256 
1257   llvm::PointerUnion<ClassTemplateDecl *,
1258                      ClassTemplatePartialSpecializationDecl *> InstFrom
1259     = D->getSpecializedTemplateOrPartial();
1260   if (Decl *InstFromD = InstFrom.dyn_cast<ClassTemplateDecl *>()) {
1261     Writer.AddDeclRef(InstFromD, Record);
1262   } else {
1263     Writer.AddDeclRef(InstFrom.get<ClassTemplatePartialSpecializationDecl *>(),
1264                       Record);
1265     Writer.AddTemplateArgumentList(&D->getTemplateInstantiationArgs(), Record);
1266   }
1267 
1268   Writer.AddTemplateArgumentList(&D->getTemplateArgs(), Record);
1269   Writer.AddSourceLocation(D->getPointOfInstantiation(), Record);
1270   Record.push_back(D->getSpecializationKind());
1271   Record.push_back(D->isCanonicalDecl());
1272 
1273   if (D->isCanonicalDecl()) {
1274     // When reading, we'll add it to the folding set of the following template.
1275     Writer.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl(), Record);
1276   }
1277 
1278   // Explicit info.
1279   Writer.AddTypeSourceInfo(D->getTypeAsWritten(), Record);
1280   if (D->getTypeAsWritten()) {
1281     Writer.AddSourceLocation(D->getExternLoc(), Record);
1282     Writer.AddSourceLocation(D->getTemplateKeywordLoc(), Record);
1283   }
1284 
1285   Code = serialization::DECL_CLASS_TEMPLATE_SPECIALIZATION;
1286 }
1287 
1288 void ASTDeclWriter::VisitClassTemplatePartialSpecializationDecl(
1289                                     ClassTemplatePartialSpecializationDecl *D) {
1290   VisitClassTemplateSpecializationDecl(D);
1291 
1292   Writer.AddTemplateParameterList(D->getTemplateParameters(), Record);
1293   Writer.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten(), Record);
1294 
1295   // These are read/set from/to the first declaration.
1296   if (D->getPreviousDecl() == nullptr) {
1297     Writer.AddDeclRef(D->getInstantiatedFromMember(), Record);
1298     Record.push_back(D->isMemberSpecialization());
1299   }
1300 
1301   Code = serialization::DECL_CLASS_TEMPLATE_PARTIAL_SPECIALIZATION;
1302 }
1303 
1304 void ASTDeclWriter::VisitVarTemplateDecl(VarTemplateDecl *D) {
1305   VisitRedeclarableTemplateDecl(D);
1306 
1307   if (D->isFirstDecl())
1308     AddTemplateSpecializations(D);
1309   Code = serialization::DECL_VAR_TEMPLATE;
1310 }
1311 
1312 void ASTDeclWriter::VisitVarTemplateSpecializationDecl(
1313     VarTemplateSpecializationDecl *D) {
1314   VisitVarDecl(D);
1315 
1316   llvm::PointerUnion<VarTemplateDecl *, VarTemplatePartialSpecializationDecl *>
1317   InstFrom = D->getSpecializedTemplateOrPartial();
1318   if (Decl *InstFromD = InstFrom.dyn_cast<VarTemplateDecl *>()) {
1319     Writer.AddDeclRef(InstFromD, Record);
1320   } else {
1321     Writer.AddDeclRef(InstFrom.get<VarTemplatePartialSpecializationDecl *>(),
1322                       Record);
1323     Writer.AddTemplateArgumentList(&D->getTemplateInstantiationArgs(), Record);
1324   }
1325 
1326   // Explicit info.
1327   Writer.AddTypeSourceInfo(D->getTypeAsWritten(), Record);
1328   if (D->getTypeAsWritten()) {
1329     Writer.AddSourceLocation(D->getExternLoc(), Record);
1330     Writer.AddSourceLocation(D->getTemplateKeywordLoc(), Record);
1331   }
1332 
1333   Writer.AddTemplateArgumentList(&D->getTemplateArgs(), Record);
1334   Writer.AddSourceLocation(D->getPointOfInstantiation(), Record);
1335   Record.push_back(D->getSpecializationKind());
1336   Record.push_back(D->isCanonicalDecl());
1337 
1338   if (D->isCanonicalDecl()) {
1339     // When reading, we'll add it to the folding set of the following template.
1340     Writer.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl(), Record);
1341   }
1342 
1343   Code = serialization::DECL_VAR_TEMPLATE_SPECIALIZATION;
1344 }
1345 
1346 void ASTDeclWriter::VisitVarTemplatePartialSpecializationDecl(
1347     VarTemplatePartialSpecializationDecl *D) {
1348   VisitVarTemplateSpecializationDecl(D);
1349 
1350   Writer.AddTemplateParameterList(D->getTemplateParameters(), Record);
1351   Writer.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten(), Record);
1352 
1353   // These are read/set from/to the first declaration.
1354   if (D->getPreviousDecl() == nullptr) {
1355     Writer.AddDeclRef(D->getInstantiatedFromMember(), Record);
1356     Record.push_back(D->isMemberSpecialization());
1357   }
1358 
1359   Code = serialization::DECL_VAR_TEMPLATE_PARTIAL_SPECIALIZATION;
1360 }
1361 
1362 void ASTDeclWriter::VisitClassScopeFunctionSpecializationDecl(
1363                                     ClassScopeFunctionSpecializationDecl *D) {
1364   VisitDecl(D);
1365   Writer.AddDeclRef(D->getSpecialization(), Record);
1366   Code = serialization::DECL_CLASS_SCOPE_FUNCTION_SPECIALIZATION;
1367 }
1368 
1369 
1370 void ASTDeclWriter::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
1371   VisitRedeclarableTemplateDecl(D);
1372 
1373   if (D->isFirstDecl())
1374     AddTemplateSpecializations(D);
1375   Code = serialization::DECL_FUNCTION_TEMPLATE;
1376 }
1377 
1378 void ASTDeclWriter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
1379   VisitTypeDecl(D);
1380 
1381   Record.push_back(D->wasDeclaredWithTypename());
1382 
1383   bool OwnsDefaultArg = D->hasDefaultArgument() &&
1384                         !D->defaultArgumentWasInherited();
1385   Record.push_back(OwnsDefaultArg);
1386   if (OwnsDefaultArg)
1387     Writer.AddTypeSourceInfo(D->getDefaultArgumentInfo(), Record);
1388 
1389   Code = serialization::DECL_TEMPLATE_TYPE_PARM;
1390 }
1391 
1392 void ASTDeclWriter::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
1393   // For an expanded parameter pack, record the number of expansion types here
1394   // so that it's easier for deserialization to allocate the right amount of
1395   // memory.
1396   if (D->isExpandedParameterPack())
1397     Record.push_back(D->getNumExpansionTypes());
1398 
1399   VisitDeclaratorDecl(D);
1400   // TemplateParmPosition.
1401   Record.push_back(D->getDepth());
1402   Record.push_back(D->getPosition());
1403 
1404   if (D->isExpandedParameterPack()) {
1405     for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1406       Writer.AddTypeRef(D->getExpansionType(I), Record);
1407       Writer.AddTypeSourceInfo(D->getExpansionTypeSourceInfo(I), Record);
1408     }
1409 
1410     Code = serialization::DECL_EXPANDED_NON_TYPE_TEMPLATE_PARM_PACK;
1411   } else {
1412     // Rest of NonTypeTemplateParmDecl.
1413     Record.push_back(D->isParameterPack());
1414     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1415                           !D->defaultArgumentWasInherited();
1416     Record.push_back(OwnsDefaultArg);
1417     if (OwnsDefaultArg)
1418       Writer.AddStmt(D->getDefaultArgument());
1419     Code = serialization::DECL_NON_TYPE_TEMPLATE_PARM;
1420   }
1421 }
1422 
1423 void ASTDeclWriter::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
1424   // For an expanded parameter pack, record the number of expansion types here
1425   // so that it's easier for deserialization to allocate the right amount of
1426   // memory.
1427   if (D->isExpandedParameterPack())
1428     Record.push_back(D->getNumExpansionTemplateParameters());
1429 
1430   VisitTemplateDecl(D);
1431   // TemplateParmPosition.
1432   Record.push_back(D->getDepth());
1433   Record.push_back(D->getPosition());
1434 
1435   if (D->isExpandedParameterPack()) {
1436     for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
1437          I != N; ++I)
1438       Writer.AddTemplateParameterList(D->getExpansionTemplateParameters(I),
1439                                       Record);
1440     Code = serialization::DECL_EXPANDED_TEMPLATE_TEMPLATE_PARM_PACK;
1441   } else {
1442     // Rest of TemplateTemplateParmDecl.
1443     Record.push_back(D->isParameterPack());
1444     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1445                           !D->defaultArgumentWasInherited();
1446     Record.push_back(OwnsDefaultArg);
1447     if (OwnsDefaultArg)
1448       Writer.AddTemplateArgumentLoc(D->getDefaultArgument(), Record);
1449     Code = serialization::DECL_TEMPLATE_TEMPLATE_PARM;
1450   }
1451 }
1452 
1453 void ASTDeclWriter::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
1454   VisitRedeclarableTemplateDecl(D);
1455   Code = serialization::DECL_TYPE_ALIAS_TEMPLATE;
1456 }
1457 
1458 void ASTDeclWriter::VisitStaticAssertDecl(StaticAssertDecl *D) {
1459   VisitDecl(D);
1460   Writer.AddStmt(D->getAssertExpr());
1461   Record.push_back(D->isFailed());
1462   Writer.AddStmt(D->getMessage());
1463   Writer.AddSourceLocation(D->getRParenLoc(), Record);
1464   Code = serialization::DECL_STATIC_ASSERT;
1465 }
1466 
1467 /// \brief Emit the DeclContext part of a declaration context decl.
1468 ///
1469 /// \param LexicalOffset the offset at which the DECL_CONTEXT_LEXICAL
1470 /// block for this declaration context is stored. May be 0 to indicate
1471 /// that there are no declarations stored within this context.
1472 ///
1473 /// \param VisibleOffset the offset at which the DECL_CONTEXT_VISIBLE
1474 /// block for this declaration context is stored. May be 0 to indicate
1475 /// that there are no declarations visible from this context. Note
1476 /// that this value will not be emitted for non-primary declaration
1477 /// contexts.
1478 void ASTDeclWriter::VisitDeclContext(DeclContext *DC, uint64_t LexicalOffset,
1479                                      uint64_t VisibleOffset) {
1480   Record.push_back(LexicalOffset);
1481   Record.push_back(VisibleOffset);
1482 }
1483 
1484 template <typename T>
1485 void ASTDeclWriter::VisitRedeclarable(Redeclarable<T> *D) {
1486   T *First = D->getFirstDecl();
1487   T *MostRecent = First->getMostRecentDecl();
1488   if (MostRecent != First) {
1489     assert(isRedeclarableDeclKind(static_cast<T *>(D)->getKind()) &&
1490            "Not considered redeclarable?");
1491 
1492     // There is more than one declaration of this entity, so we will need to
1493     // write a redeclaration chain.
1494     Writer.AddDeclRef(First, Record);
1495     Writer.Redeclarations.insert(First);
1496 
1497     auto *Previous = D->getPreviousDecl();
1498 
1499     // In a modules build, we can have imported declarations after a local
1500     // canonical declaration. If this is the first local declaration, emit
1501     // a list of all such imported declarations so that we can ensure they
1502     // are loaded before we are. This allows us to rebuild the redecl chain
1503     // in the right order on reload (all declarations imported by a module
1504     // should be before all declarations provided by that module).
1505     bool EmitImportedMergedCanonicalDecls = false;
1506     if (Context.getLangOpts().Modules && Writer.Chain) {
1507       auto *PreviousLocal = Previous;
1508       while (PreviousLocal && PreviousLocal->isFromASTFile())
1509         PreviousLocal = PreviousLocal->getPreviousDecl();
1510       if (!PreviousLocal)
1511         EmitImportedMergedCanonicalDecls = true;
1512     }
1513     if (EmitImportedMergedCanonicalDecls) {
1514       llvm::SmallMapVector<ModuleFile*, Decl*, 16> FirstInModule;
1515       for (auto *Redecl = MostRecent; Redecl;
1516            Redecl = Redecl->getPreviousDecl())
1517         if (Redecl->isFromASTFile())
1518           FirstInModule[Writer.Chain->getOwningModuleFile(Redecl)] = Redecl;
1519       // FIXME: If FirstInModule has entries for modules A and B, and B imports
1520       // A (directly or indirectly), we don't need to write the entry for A.
1521       Record.push_back(FirstInModule.size());
1522       for (auto I = FirstInModule.rbegin(), E = FirstInModule.rend();
1523            I != E; ++I)
1524         Writer.AddDeclRef(I->second, Record);
1525     } else
1526       Record.push_back(0);
1527 
1528     // Make sure that we serialize both the previous and the most-recent
1529     // declarations, which (transitively) ensures that all declarations in the
1530     // chain get serialized.
1531     //
1532     // FIXME: This is not correct; when we reach an imported declaration we
1533     // won't emit its previous declaration.
1534     (void)Writer.GetDeclRef(Previous);
1535     (void)Writer.GetDeclRef(MostRecent);
1536   } else {
1537     // We use the sentinel value 0 to indicate an only declaration.
1538     Record.push_back(0);
1539   }
1540 }
1541 
1542 void ASTDeclWriter::VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D) {
1543   Record.push_back(D->varlist_size());
1544   VisitDecl(D);
1545   for (auto *I : D->varlists())
1546     Writer.AddStmt(I);
1547   Code = serialization::DECL_OMP_THREADPRIVATE;
1548 }
1549 
1550 //===----------------------------------------------------------------------===//
1551 // ASTWriter Implementation
1552 //===----------------------------------------------------------------------===//
1553 
1554 void ASTWriter::WriteDeclAbbrevs() {
1555   using namespace llvm;
1556 
1557   BitCodeAbbrev *Abv;
1558 
1559   // Abbreviation for DECL_FIELD
1560   Abv = new BitCodeAbbrev();
1561   Abv->Add(BitCodeAbbrevOp(serialization::DECL_FIELD));
1562   // Decl
1563   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1564   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1565   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1566   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1567   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1568   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1569   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1570   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1571   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1572   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1573   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1574   // NamedDecl
1575   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1576   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1577   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1578   // ValueDecl
1579   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1580   // DeclaratorDecl
1581   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1582   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1583   // FieldDecl
1584   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1585   Abv->Add(BitCodeAbbrevOp(0));                       //getBitWidth
1586   // Type Source Info
1587   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1588   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1589   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1590   DeclFieldAbbrev = Stream.EmitAbbrev(Abv);
1591 
1592   // Abbreviation for DECL_OBJC_IVAR
1593   Abv = new BitCodeAbbrev();
1594   Abv->Add(BitCodeAbbrevOp(serialization::DECL_OBJC_IVAR));
1595   // Decl
1596   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1597   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1598   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1599   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1600   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1601   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1602   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1603   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1604   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1605   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1606   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1607   // NamedDecl
1608   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1609   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1610   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1611   // ValueDecl
1612   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1613   // DeclaratorDecl
1614   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1615   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1616   // FieldDecl
1617   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1618   Abv->Add(BitCodeAbbrevOp(0));                       //getBitWidth
1619   // ObjC Ivar
1620   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getAccessControl
1621   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getSynthesize
1622   // Type Source Info
1623   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1624   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1625   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1626   DeclObjCIvarAbbrev = Stream.EmitAbbrev(Abv);
1627 
1628   // Abbreviation for DECL_ENUM
1629   Abv = new BitCodeAbbrev();
1630   Abv->Add(BitCodeAbbrevOp(serialization::DECL_ENUM));
1631   // Redeclarable
1632   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1633   // Decl
1634   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1635   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1636   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1637   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1638   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1639   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1640   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1641   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1642   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1643   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1644   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1645   // NamedDecl
1646   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1647   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1648   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1649   // TypeDecl
1650   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1651   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1652   // TagDecl
1653   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
1654   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
1655   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
1656   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
1657   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
1658   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
1659   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1660   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
1661   // EnumDecl
1662   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddTypeRef
1663   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IntegerType
1664   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getPromotionType
1665   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumPositiveBits
1666   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumNegativeBits
1667   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScoped
1668   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScopedUsingClassTag
1669   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isFixed
1670   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InstantiatedMembEnum
1671   // DC
1672   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
1673   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
1674   DeclEnumAbbrev = Stream.EmitAbbrev(Abv);
1675 
1676   // Abbreviation for DECL_RECORD
1677   Abv = new BitCodeAbbrev();
1678   Abv->Add(BitCodeAbbrevOp(serialization::DECL_RECORD));
1679   // Redeclarable
1680   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1681   // Decl
1682   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1683   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1684   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1685   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1686   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1687   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1688   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1689   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1690   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1691   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1692   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1693   // NamedDecl
1694   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1695   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1696   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1697   // TypeDecl
1698   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1699   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1700   // TagDecl
1701   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
1702   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
1703   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
1704   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
1705   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
1706   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
1707   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1708   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
1709   // RecordDecl
1710   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // FlexibleArrayMember
1711   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // AnonymousStructUnion
1712   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasObjectMember
1713   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasVolatileMember
1714   // DC
1715   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
1716   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
1717   DeclRecordAbbrev = Stream.EmitAbbrev(Abv);
1718 
1719   // Abbreviation for DECL_PARM_VAR
1720   Abv = new BitCodeAbbrev();
1721   Abv->Add(BitCodeAbbrevOp(serialization::DECL_PARM_VAR));
1722   // Redeclarable
1723   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1724   // Decl
1725   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1726   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1727   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1728   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1729   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1730   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1731   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1732   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1733   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1734   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1735   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1736   // NamedDecl
1737   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1738   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1739   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1740   // ValueDecl
1741   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1742   // DeclaratorDecl
1743   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1744   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1745   // VarDecl
1746   Abv->Add(BitCodeAbbrevOp(0));                       // StorageClass
1747   Abv->Add(BitCodeAbbrevOp(0));                       // getTSCSpec
1748   Abv->Add(BitCodeAbbrevOp(0));                       // hasCXXDirectInitializer
1749   Abv->Add(BitCodeAbbrevOp(0));                       // Linkage
1750   Abv->Add(BitCodeAbbrevOp(0));                       // HasInit
1751   Abv->Add(BitCodeAbbrevOp(0));                   // HasMemberSpecializationInfo
1752   // ParmVarDecl
1753   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsObjCMethodParameter
1754   Abv->Add(BitCodeAbbrevOp(0));                       // ScopeDepth
1755   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ScopeIndex
1756   Abv->Add(BitCodeAbbrevOp(0));                       // ObjCDeclQualifier
1757   Abv->Add(BitCodeAbbrevOp(0));                       // KNRPromoted
1758   Abv->Add(BitCodeAbbrevOp(0));                       // HasInheritedDefaultArg
1759   Abv->Add(BitCodeAbbrevOp(0));                   // HasUninstantiatedDefaultArg
1760   // Type Source Info
1761   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1762   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1763   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1764   DeclParmVarAbbrev = Stream.EmitAbbrev(Abv);
1765 
1766   // Abbreviation for DECL_TYPEDEF
1767   Abv = new BitCodeAbbrev();
1768   Abv->Add(BitCodeAbbrevOp(serialization::DECL_TYPEDEF));
1769   // Redeclarable
1770   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1771   // Decl
1772   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1773   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1774   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1775   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1776   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1777   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isUsed
1778   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isReferenced
1779   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1780   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // C++ AccessSpecifier
1781   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1782   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1783   // NamedDecl
1784   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1785   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1786   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1787   // TypeDecl
1788   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1789   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1790   // TypedefDecl
1791   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1792   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1793   DeclTypedefAbbrev = Stream.EmitAbbrev(Abv);
1794 
1795   // Abbreviation for DECL_VAR
1796   Abv = new BitCodeAbbrev();
1797   Abv->Add(BitCodeAbbrevOp(serialization::DECL_VAR));
1798   // Redeclarable
1799   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1800   // Decl
1801   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1802   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1803   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1804   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1805   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1806   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1807   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1808   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1809   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1810   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1811   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1812   // NamedDecl
1813   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1814   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1815   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1816   // ValueDecl
1817   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1818   // DeclaratorDecl
1819   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1820   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1821   // VarDecl
1822   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // StorageClass
1823   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // getTSCSpec
1824   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // CXXDirectInitializer
1825   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isExceptionVariable
1826   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isNRVOVariable
1827   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCXXForRangeDecl
1828   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isARCPseudoStrong
1829   Abv->Add(BitCodeAbbrevOp(0));                         // isConstexpr
1830   Abv->Add(BitCodeAbbrevOp(0));                         // isInitCapture
1831   Abv->Add(BitCodeAbbrevOp(0));                         // isPrevDeclInSameScope
1832   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
1833   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // HasInit
1834   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // HasMemberSpecInfo
1835   // Type Source Info
1836   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1837   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1838   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1839   DeclVarAbbrev = Stream.EmitAbbrev(Abv);
1840 
1841   // Abbreviation for DECL_CXX_METHOD
1842   Abv = new BitCodeAbbrev();
1843   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CXX_METHOD));
1844   // RedeclarableDecl
1845   Abv->Add(BitCodeAbbrevOp(0));                         // CanonicalDecl
1846   // Decl
1847   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // DeclContext
1848   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalDeclContext
1849   Abv->Add(BitCodeAbbrevOp(0));                         // Invalid
1850   Abv->Add(BitCodeAbbrevOp(0));                         // HasAttrs
1851   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Implicit
1852   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Used
1853   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Referenced
1854   Abv->Add(BitCodeAbbrevOp(0));                         // InObjCContainer
1855   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // Access
1856   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ModulePrivate
1857   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SubmoduleID
1858   // NamedDecl
1859   Abv->Add(BitCodeAbbrevOp(DeclarationName::Identifier)); // NameKind
1860   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Identifier
1861   Abv->Add(BitCodeAbbrevOp(0));                         // AnonDeclNumber
1862   // ValueDecl
1863   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Type
1864   // DeclaratorDecl
1865   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InnerLocStart
1866   Abv->Add(BitCodeAbbrevOp(0));                         // HasExtInfo
1867   // FunctionDecl
1868   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 11)); // IDNS
1869   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // StorageClass
1870   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Inline
1871   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // InlineSpecified
1872   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // VirtualAsWritten
1873   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Pure
1874   Abv->Add(BitCodeAbbrevOp(0));                         // HasInheritedProto
1875   Abv->Add(BitCodeAbbrevOp(1));                         // HasWrittenProto
1876   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Deleted
1877   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Trivial
1878   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Defaulted
1879   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ExplicitlyDefaulted
1880   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ImplicitReturnZero
1881   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Constexpr
1882   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // SkippedBody
1883   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // LateParsed
1884   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
1885   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LocEnd
1886   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // TemplateKind
1887   // This Array slurps the rest of the record. Fortunately we want to encode
1888   // (nearly) all the remaining (variable number of) fields in the same way.
1889   //
1890   // This is the function template information if any, then
1891   //         NumParams and Params[] from FunctionDecl, and
1892   //         NumOverriddenMethods, OverriddenMethods[] from CXXMethodDecl.
1893   //
1894   //  Add an AbbrevOp for 'size then elements' and use it here.
1895   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1896   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1897   DeclCXXMethodAbbrev = Stream.EmitAbbrev(Abv);
1898 
1899   // Abbreviation for EXPR_DECL_REF
1900   Abv = new BitCodeAbbrev();
1901   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_DECL_REF));
1902   //Stmt
1903   //Expr
1904   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1905   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
1906   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
1907   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
1908   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
1909   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
1910   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
1911   //DeclRefExpr
1912   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HasQualifier
1913   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //GetDeclFound
1914   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ExplicitTemplateArgs
1915   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HadMultipleCandidates
1916   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1917                            1)); // RefersToEnclosingVariableOrCapture
1918   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclRef
1919   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
1920   DeclRefExprAbbrev = Stream.EmitAbbrev(Abv);
1921 
1922   // Abbreviation for EXPR_INTEGER_LITERAL
1923   Abv = new BitCodeAbbrev();
1924   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_INTEGER_LITERAL));
1925   //Stmt
1926   //Expr
1927   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1928   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
1929   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
1930   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
1931   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
1932   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
1933   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
1934   //Integer Literal
1935   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
1936   Abv->Add(BitCodeAbbrevOp(32));                      // Bit Width
1937   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Value
1938   IntegerLiteralAbbrev = Stream.EmitAbbrev(Abv);
1939 
1940   // Abbreviation for EXPR_CHARACTER_LITERAL
1941   Abv = new BitCodeAbbrev();
1942   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_CHARACTER_LITERAL));
1943   //Stmt
1944   //Expr
1945   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1946   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
1947   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
1948   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
1949   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
1950   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
1951   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
1952   //Character Literal
1953   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getValue
1954   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
1955   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // getKind
1956   CharacterLiteralAbbrev = Stream.EmitAbbrev(Abv);
1957 
1958   // Abbreviation for EXPR_IMPLICIT_CAST
1959   Abv = new BitCodeAbbrev();
1960   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_IMPLICIT_CAST));
1961   // Stmt
1962   // Expr
1963   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1964   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
1965   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
1966   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
1967   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
1968   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
1969   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
1970   // CastExpr
1971   Abv->Add(BitCodeAbbrevOp(0)); // PathSize
1972   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 6)); // CastKind
1973   // ImplicitCastExpr
1974   ExprImplicitCastAbbrev = Stream.EmitAbbrev(Abv);
1975 
1976   Abv = new BitCodeAbbrev();
1977   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_LEXICAL));
1978   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1979   DeclContextLexicalAbbrev = Stream.EmitAbbrev(Abv);
1980 
1981   Abv = new BitCodeAbbrev();
1982   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_VISIBLE));
1983   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1984   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1985   DeclContextVisibleLookupAbbrev = Stream.EmitAbbrev(Abv);
1986 }
1987 
1988 /// isRequiredDecl - Check if this is a "required" Decl, which must be seen by
1989 /// consumers of the AST.
1990 ///
1991 /// Such decls will always be deserialized from the AST file, so we would like
1992 /// this to be as restrictive as possible. Currently the predicate is driven by
1993 /// code generation requirements, if other clients have a different notion of
1994 /// what is "required" then we may have to consider an alternate scheme where
1995 /// clients can iterate over the top-level decls and get information on them,
1996 /// without necessary deserializing them. We could explicitly require such
1997 /// clients to use a separate API call to "realize" the decl. This should be
1998 /// relatively painless since they would presumably only do it for top-level
1999 /// decls.
2000 static bool isRequiredDecl(const Decl *D, ASTContext &Context) {
2001   // An ObjCMethodDecl is never considered as "required" because its
2002   // implementation container always is.
2003 
2004   // File scoped assembly or obj-c implementation must be seen. ImportDecl is
2005   // used by codegen to determine the set of imported modules to search for
2006   // inputs for automatic linking.
2007   if (isa<FileScopeAsmDecl>(D) || isa<ObjCImplDecl>(D) || isa<ImportDecl>(D))
2008     return true;
2009 
2010   return Context.DeclMustBeEmitted(D);
2011 }
2012 
2013 void ASTWriter::WriteDecl(ASTContext &Context, Decl *D) {
2014   // Switch case IDs are per Decl.
2015   ClearSwitchCaseIDs();
2016 
2017   RecordData Record;
2018   ASTDeclWriter W(*this, Context, Record);
2019 
2020   // Determine the ID for this declaration.
2021   serialization::DeclID ID;
2022   if (D->isFromASTFile()) {
2023     assert(isRewritten(D) && "should not be emitting imported decl");
2024     ID = getDeclID(D);
2025   } else {
2026     serialization::DeclID &IDR = DeclIDs[D];
2027     if (IDR == 0)
2028       IDR = NextDeclID++;
2029 
2030     ID= IDR;
2031   }
2032 
2033   bool isReplacingADecl = ID < FirstDeclID;
2034 
2035   // If this declaration is also a DeclContext, write blocks for the
2036   // declarations that lexically stored inside its context and those
2037   // declarations that are visible from its context. These blocks
2038   // are written before the declaration itself so that we can put
2039   // their offsets into the record for the declaration.
2040   uint64_t LexicalOffset = 0;
2041   uint64_t VisibleOffset = 0;
2042   DeclContext *DC = dyn_cast<DeclContext>(D);
2043   if (DC) {
2044     if (isReplacingADecl) {
2045       // It is replacing a decl from a chained PCH; make sure that the
2046       // DeclContext is fully loaded.
2047       if (DC->hasExternalLexicalStorage())
2048         DC->LoadLexicalDeclsFromExternalStorage();
2049       if (DC->hasExternalVisibleStorage())
2050         Chain->completeVisibleDeclsMap(DC);
2051     }
2052     LexicalOffset = WriteDeclContextLexicalBlock(Context, DC);
2053     VisibleOffset = WriteDeclContextVisibleBlock(Context, DC);
2054   }
2055 
2056   if (isReplacingADecl) {
2057     // We're replacing a decl in a previous file.
2058     ReplacedDecls.push_back(ReplacedDeclInfo(ID, Stream.GetCurrentBitNo(),
2059                                              D->getLocation()));
2060   } else {
2061     unsigned Index = ID - FirstDeclID;
2062 
2063     // Record the offset for this declaration
2064     SourceLocation Loc = D->getLocation();
2065     if (DeclOffsets.size() == Index)
2066       DeclOffsets.push_back(DeclOffset(Loc, Stream.GetCurrentBitNo()));
2067     else if (DeclOffsets.size() < Index) {
2068       DeclOffsets.resize(Index+1);
2069       DeclOffsets[Index].setLocation(Loc);
2070       DeclOffsets[Index].BitOffset = Stream.GetCurrentBitNo();
2071     }
2072 
2073     SourceManager &SM = Context.getSourceManager();
2074     if (Loc.isValid() && SM.isLocalSourceLocation(Loc))
2075       associateDeclWithFile(D, ID);
2076   }
2077 
2078   // Build and emit a record for this declaration
2079   Record.clear();
2080   W.Code = (serialization::DeclCode)0;
2081   W.AbbrevToUse = 0;
2082   W.Visit(D);
2083   if (DC) W.VisitDeclContext(DC, LexicalOffset, VisibleOffset);
2084 
2085   if (!W.Code)
2086     llvm::report_fatal_error(StringRef("unexpected declaration kind '") +
2087                             D->getDeclKindName() + "'");
2088   Stream.EmitRecord(W.Code, Record, W.AbbrevToUse);
2089 
2090   // Flush any expressions, base specifiers, and ctor initializers that
2091   // were written as part of this declaration.
2092   FlushPendingAfterDecl();
2093 
2094   // Note declarations that should be deserialized eagerly so that we can add
2095   // them to a record in the AST file later.
2096   if (isRequiredDecl(D, Context))
2097     EagerlyDeserializedDecls.push_back(ID);
2098 }
2099 
2100 void ASTWriter::AddFunctionDefinition(const FunctionDecl *FD,
2101                                       RecordData &Record) {
2102   ClearSwitchCaseIDs();
2103 
2104   ASTDeclWriter W(*this, FD->getASTContext(), Record);
2105   W.AddFunctionDefinition(FD);
2106 }
2107