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