1 //===--- ASTWriterDecl.cpp - Declaration Serialization --------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //  This file implements serialization for Declarations.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Serialization/ASTWriter.h"
15 #include "ASTCommon.h"
16 #include "clang/AST/DeclCXX.h"
17 #include "clang/AST/DeclContextInternals.h"
18 #include "clang/AST/DeclTemplate.h"
19 #include "clang/AST/DeclVisitor.h"
20 #include "clang/AST/Expr.h"
21 #include "clang/Basic/SourceManager.h"
22 #include "clang/Serialization/ASTReader.h"
23 #include "llvm/ADT/Twine.h"
24 #include "llvm/Bitcode/BitstreamWriter.h"
25 #include "llvm/Support/ErrorHandling.h"
26 using namespace clang;
27 using namespace serialization;
28 
29 //===----------------------------------------------------------------------===//
30 // Declaration serialization
31 //===----------------------------------------------------------------------===//
32 
33 namespace clang {
34   class ASTDeclWriter : public DeclVisitor<ASTDeclWriter, void> {
35 
36     ASTWriter &Writer;
37     ASTContext &Context;
38     typedef ASTWriter::RecordData RecordData;
39     RecordData &Record;
40 
41   public:
42     serialization::DeclCode Code;
43     unsigned AbbrevToUse;
44 
45     ASTDeclWriter(ASTWriter &Writer, ASTContext &Context, RecordData &Record)
46       : Writer(Writer), Context(Context), Record(Record) {
47     }
48 
49     void Visit(Decl *D);
50 
51     void VisitDecl(Decl *D);
52     void VisitTranslationUnitDecl(TranslationUnitDecl *D);
53     void VisitNamedDecl(NamedDecl *D);
54     void VisitLabelDecl(LabelDecl *LD);
55     void VisitNamespaceDecl(NamespaceDecl *D);
56     void VisitUsingDirectiveDecl(UsingDirectiveDecl *D);
57     void VisitNamespaceAliasDecl(NamespaceAliasDecl *D);
58     void VisitTypeDecl(TypeDecl *D);
59     void VisitTypedefNameDecl(TypedefNameDecl *D);
60     void VisitTypedefDecl(TypedefDecl *D);
61     void VisitTypeAliasDecl(TypeAliasDecl *D);
62     void VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D);
63     void VisitTagDecl(TagDecl *D);
64     void VisitEnumDecl(EnumDecl *D);
65     void VisitRecordDecl(RecordDecl *D);
66     void VisitCXXRecordDecl(CXXRecordDecl *D);
67     void VisitClassTemplateSpecializationDecl(
68                                             ClassTemplateSpecializationDecl *D);
69     void VisitClassTemplatePartialSpecializationDecl(
70                                      ClassTemplatePartialSpecializationDecl *D);
71     void VisitVarTemplateSpecializationDecl(VarTemplateSpecializationDecl *D);
72     void VisitVarTemplatePartialSpecializationDecl(
73         VarTemplatePartialSpecializationDecl *D);
74     void VisitClassScopeFunctionSpecializationDecl(
75                                        ClassScopeFunctionSpecializationDecl *D);
76     void VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
77     void VisitValueDecl(ValueDecl *D);
78     void VisitEnumConstantDecl(EnumConstantDecl *D);
79     void VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D);
80     void VisitDeclaratorDecl(DeclaratorDecl *D);
81     void VisitFunctionDecl(FunctionDecl *D);
82     void VisitCXXMethodDecl(CXXMethodDecl *D);
83     void VisitCXXConstructorDecl(CXXConstructorDecl *D);
84     void VisitCXXDestructorDecl(CXXDestructorDecl *D);
85     void VisitCXXConversionDecl(CXXConversionDecl *D);
86     void VisitFieldDecl(FieldDecl *D);
87     void VisitMSPropertyDecl(MSPropertyDecl *D);
88     void VisitIndirectFieldDecl(IndirectFieldDecl *D);
89     void VisitVarDecl(VarDecl *D);
90     void VisitImplicitParamDecl(ImplicitParamDecl *D);
91     void VisitParmVarDecl(ParmVarDecl *D);
92     void VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
93     void VisitTemplateDecl(TemplateDecl *D);
94     void VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D);
95     void VisitClassTemplateDecl(ClassTemplateDecl *D);
96     void VisitVarTemplateDecl(VarTemplateDecl *D);
97     void VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
98     void VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
99     void VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D);
100     void VisitUsingDecl(UsingDecl *D);
101     void VisitUsingShadowDecl(UsingShadowDecl *D);
102     void VisitLinkageSpecDecl(LinkageSpecDecl *D);
103     void VisitFileScopeAsmDecl(FileScopeAsmDecl *D);
104     void VisitImportDecl(ImportDecl *D);
105     void VisitAccessSpecDecl(AccessSpecDecl *D);
106     void VisitFriendDecl(FriendDecl *D);
107     void VisitFriendTemplateDecl(FriendTemplateDecl *D);
108     void VisitStaticAssertDecl(StaticAssertDecl *D);
109     void VisitBlockDecl(BlockDecl *D);
110     void VisitCapturedDecl(CapturedDecl *D);
111     void VisitEmptyDecl(EmptyDecl *D);
112 
113     void VisitDeclContext(DeclContext *DC, uint64_t LexicalOffset,
114                           uint64_t VisibleOffset);
115     template <typename T> void VisitRedeclarable(Redeclarable<T> *D);
116 
117 
118     // FIXME: Put in the same order is DeclNodes.td?
119     void VisitObjCMethodDecl(ObjCMethodDecl *D);
120     void VisitObjCContainerDecl(ObjCContainerDecl *D);
121     void VisitObjCInterfaceDecl(ObjCInterfaceDecl *D);
122     void VisitObjCIvarDecl(ObjCIvarDecl *D);
123     void VisitObjCProtocolDecl(ObjCProtocolDecl *D);
124     void VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D);
125     void VisitObjCCategoryDecl(ObjCCategoryDecl *D);
126     void VisitObjCImplDecl(ObjCImplDecl *D);
127     void VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D);
128     void VisitObjCImplementationDecl(ObjCImplementationDecl *D);
129     void VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D);
130     void VisitObjCPropertyDecl(ObjCPropertyDecl *D);
131     void VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D);
132     void VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D);
133 
134     void AddFunctionDefinition(const FunctionDecl *FD) {
135       assert(FD->doesThisDeclarationHaveABody());
136       if (auto *CD = dyn_cast<CXXConstructorDecl>(FD)) {
137         Record.push_back(CD->NumCtorInitializers);
138         if (CD->NumCtorInitializers)
139           Writer.AddCXXCtorInitializersRef(
140               llvm::makeArrayRef(CD->init_begin(), CD->init_end()), Record);
141       }
142       Writer.AddStmt(FD->getBody());
143     }
144 
145     /// Get the specialization decl from an entry in the specialization list.
146     template <typename EntryType>
147     typename RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::DeclType *
148     getSpecializationDecl(EntryType &T) {
149       return RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::getDecl(&T);
150     }
151 
152     /// Get the list of partial specializations from a template's common ptr.
153     template<typename T>
154     decltype(T::PartialSpecializations) &getPartialSpecializations(T *Common) {
155       return Common->PartialSpecializations;
156     }
157     ArrayRef<Decl> getPartialSpecializations(FunctionTemplateDecl::Common *) {
158       return None;
159     }
160 
161     template<typename Decl>
162     void AddTemplateSpecializations(Decl *D) {
163       auto *Common = D->getCommonPtr();
164 
165       // If we have any lazy specializations, and the external AST source is
166       // our chained AST reader, we can just write out the DeclIDs. Otherwise,
167       // we need to resolve them to actual declarations.
168       if (Writer.Chain != Writer.Context->getExternalSource() &&
169           Common->LazySpecializations) {
170         D->LoadLazySpecializations();
171         assert(!Common->LazySpecializations);
172       }
173 
174       auto &Specializations = Common->Specializations;
175       auto &&PartialSpecializations = getPartialSpecializations(Common);
176       ArrayRef<DeclID> LazySpecializations;
177       if (auto *LS = Common->LazySpecializations)
178         LazySpecializations = ArrayRef<DeclID>(LS + 1, LS + 1 + LS[0]);
179 
180       Record.push_back(Specializations.size() +
181                        PartialSpecializations.size() +
182                        LazySpecializations.size());
183       for (auto &Entry : Specializations) {
184         auto *D = getSpecializationDecl(Entry);
185         assert(D->isCanonicalDecl() && "non-canonical decl in set");
186         Writer.AddDeclRef(D, Record);
187       }
188       for (auto &Entry : PartialSpecializations) {
189         auto *D = getSpecializationDecl(Entry);
190         assert(D->isCanonicalDecl() && "non-canonical decl in set");
191         Writer.AddDeclRef(D, Record);
192       }
193       Record.append(LazySpecializations.begin(), LazySpecializations.end());
194     }
195   };
196 }
197 
198 void ASTDeclWriter::Visit(Decl *D) {
199   DeclVisitor<ASTDeclWriter>::Visit(D);
200 
201   // Source locations require array (variable-length) abbreviations.  The
202   // abbreviation infrastructure requires that arrays are encoded last, so
203   // we handle it here in the case of those classes derived from DeclaratorDecl
204   if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D)){
205     Writer.AddTypeSourceInfo(DD->getTypeSourceInfo(), Record);
206   }
207 
208   // Handle FunctionDecl's body here and write it after all other Stmts/Exprs
209   // have been written. We want it last because we will not read it back when
210   // retrieving it from the AST, we'll just lazily set the offset.
211   if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
212     Record.push_back(FD->doesThisDeclarationHaveABody());
213     if (FD->doesThisDeclarationHaveABody())
214       AddFunctionDefinition(FD);
215   }
216 }
217 
218 void ASTDeclWriter::VisitDecl(Decl *D) {
219   Writer.AddDeclRef(cast_or_null<Decl>(D->getDeclContext()), Record);
220   Writer.AddDeclRef(cast_or_null<Decl>(D->getLexicalDeclContext()), Record);
221   Record.push_back(D->isInvalidDecl());
222   Record.push_back(D->hasAttrs());
223   if (D->hasAttrs())
224     Writer.WriteAttributes(llvm::makeArrayRef(D->getAttrs().begin(),
225                                               D->getAttrs().size()), Record);
226   Record.push_back(D->isImplicit());
227   Record.push_back(D->isUsed(false));
228   Record.push_back(D->isReferenced());
229   Record.push_back(D->isTopLevelDeclInObjCContainer());
230   Record.push_back(D->getAccess());
231   Record.push_back(D->isModulePrivate());
232   Record.push_back(Writer.inferSubmoduleIDFromLocation(D->getLocation()));
233 
234   // If this declaration injected a name into a context different from its
235   // lexical context, and that context is an imported namespace, we need to
236   // update its visible declarations to include this name.
237   //
238   // This happens when we instantiate a class with a friend declaration or a
239   // function with a local extern declaration, for instance.
240   if (D->isOutOfLine()) {
241     auto *DC = D->getDeclContext();
242     while (auto *NS = dyn_cast<NamespaceDecl>(DC->getRedeclContext())) {
243       if (!NS->isFromASTFile())
244         break;
245       Writer.UpdatedDeclContexts.insert(NS->getPrimaryContext());
246       if (!NS->isInlineNamespace())
247         break;
248       DC = NS->getParent();
249     }
250   }
251 }
252 
253 void ASTDeclWriter::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
254   llvm_unreachable("Translation units aren't directly serialized");
255 }
256 
257 void ASTDeclWriter::VisitNamedDecl(NamedDecl *D) {
258   VisitDecl(D);
259   Writer.AddDeclarationName(D->getDeclName(), Record);
260   Record.push_back(needsAnonymousDeclarationNumber(D)
261                        ? Writer.getAnonymousDeclarationNumber(D)
262                        : 0);
263 }
264 
265 void ASTDeclWriter::VisitTypeDecl(TypeDecl *D) {
266   VisitNamedDecl(D);
267   Writer.AddSourceLocation(D->getLocStart(), Record);
268   Writer.AddTypeRef(QualType(D->getTypeForDecl(), 0), Record);
269 }
270 
271 void ASTDeclWriter::VisitTypedefNameDecl(TypedefNameDecl *D) {
272   VisitRedeclarable(D);
273   VisitTypeDecl(D);
274   Writer.AddTypeSourceInfo(D->getTypeSourceInfo(), Record);
275   Record.push_back(D->isModed());
276   if (D->isModed())
277     Writer.AddTypeRef(D->getUnderlyingType(), Record);
278 }
279 
280 void ASTDeclWriter::VisitTypedefDecl(TypedefDecl *D) {
281   VisitTypedefNameDecl(D);
282   if (!D->hasAttrs() &&
283       !D->isImplicit() &&
284       D->getFirstDecl() == D->getMostRecentDecl() &&
285       !D->isInvalidDecl() &&
286       !D->isTopLevelDeclInObjCContainer() &&
287       !D->isModulePrivate() &&
288       !needsAnonymousDeclarationNumber(D) &&
289       D->getDeclName().getNameKind() == DeclarationName::Identifier)
290     AbbrevToUse = Writer.getDeclTypedefAbbrev();
291 
292   Code = serialization::DECL_TYPEDEF;
293 }
294 
295 void ASTDeclWriter::VisitTypeAliasDecl(TypeAliasDecl *D) {
296   VisitTypedefNameDecl(D);
297   Writer.AddDeclRef(D->getDescribedAliasTemplate(), Record);
298   Code = serialization::DECL_TYPEALIAS;
299 }
300 
301 void ASTDeclWriter::VisitTagDecl(TagDecl *D) {
302   VisitRedeclarable(D);
303   VisitTypeDecl(D);
304   Record.push_back(D->getIdentifierNamespace());
305   Record.push_back((unsigned)D->getTagKind()); // FIXME: stable encoding
306   if (!isa<CXXRecordDecl>(D))
307     Record.push_back(D->isCompleteDefinition());
308   Record.push_back(D->isEmbeddedInDeclarator());
309   Record.push_back(D->isFreeStanding());
310   Record.push_back(D->isCompleteDefinitionRequired());
311   Writer.AddSourceLocation(D->getRBraceLoc(), Record);
312 
313   if (D->hasExtInfo()) {
314     Record.push_back(1);
315     Writer.AddQualifierInfo(*D->getExtInfo(), Record);
316   } else if (auto *TD = D->getTypedefNameForAnonDecl()) {
317     Record.push_back(2);
318     Writer.AddDeclRef(TD, Record);
319     Writer.AddIdentifierRef(TD->getDeclName().getAsIdentifierInfo(), Record);
320   } else if (auto *DD = D->getDeclaratorForAnonDecl()) {
321     Record.push_back(3);
322     Writer.AddDeclRef(DD, Record);
323   } else {
324     Record.push_back(0);
325   }
326 }
327 
328 void ASTDeclWriter::VisitEnumDecl(EnumDecl *D) {
329   VisitTagDecl(D);
330   Writer.AddTypeSourceInfo(D->getIntegerTypeSourceInfo(), Record);
331   if (!D->getIntegerTypeSourceInfo())
332     Writer.AddTypeRef(D->getIntegerType(), Record);
333   Writer.AddTypeRef(D->getPromotionType(), Record);
334   Record.push_back(D->getNumPositiveBits());
335   Record.push_back(D->getNumNegativeBits());
336   Record.push_back(D->isScoped());
337   Record.push_back(D->isScopedUsingClassTag());
338   Record.push_back(D->isFixed());
339   if (MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo()) {
340     Writer.AddDeclRef(MemberInfo->getInstantiatedFrom(), Record);
341     Record.push_back(MemberInfo->getTemplateSpecializationKind());
342     Writer.AddSourceLocation(MemberInfo->getPointOfInstantiation(), Record);
343   } else {
344     Writer.AddDeclRef(nullptr, Record);
345   }
346 
347   if (!D->hasAttrs() &&
348       !D->isImplicit() &&
349       !D->isUsed(false) &&
350       !D->hasExtInfo() &&
351       !D->getTypedefNameForAnonDecl() &&
352       !D->getDeclaratorForAnonDecl() &&
353       D->getFirstDecl() == D->getMostRecentDecl() &&
354       !D->isInvalidDecl() &&
355       !D->isReferenced() &&
356       !D->isTopLevelDeclInObjCContainer() &&
357       D->getAccess() == AS_none &&
358       !D->isModulePrivate() &&
359       !CXXRecordDecl::classofKind(D->getKind()) &&
360       !D->getIntegerTypeSourceInfo() &&
361       !D->getMemberSpecializationInfo() &&
362       !needsAnonymousDeclarationNumber(D) &&
363       D->getDeclName().getNameKind() == DeclarationName::Identifier)
364     AbbrevToUse = Writer.getDeclEnumAbbrev();
365 
366   Code = serialization::DECL_ENUM;
367 }
368 
369 void ASTDeclWriter::VisitRecordDecl(RecordDecl *D) {
370   VisitTagDecl(D);
371   Record.push_back(D->hasFlexibleArrayMember());
372   Record.push_back(D->isAnonymousStructOrUnion());
373   Record.push_back(D->hasObjectMember());
374   Record.push_back(D->hasVolatileMember());
375 
376   if (!D->hasAttrs() &&
377       !D->isImplicit() &&
378       !D->isUsed(false) &&
379       !D->hasExtInfo() &&
380       !D->getTypedefNameForAnonDecl() &&
381       !D->getDeclaratorForAnonDecl() &&
382       D->getFirstDecl() == D->getMostRecentDecl() &&
383       !D->isInvalidDecl() &&
384       !D->isReferenced() &&
385       !D->isTopLevelDeclInObjCContainer() &&
386       D->getAccess() == AS_none &&
387       !D->isModulePrivate() &&
388       !CXXRecordDecl::classofKind(D->getKind()) &&
389       !needsAnonymousDeclarationNumber(D) &&
390       D->getDeclName().getNameKind() == DeclarationName::Identifier)
391     AbbrevToUse = Writer.getDeclRecordAbbrev();
392 
393   Code = serialization::DECL_RECORD;
394 }
395 
396 void ASTDeclWriter::VisitValueDecl(ValueDecl *D) {
397   VisitNamedDecl(D);
398   Writer.AddTypeRef(D->getType(), Record);
399 }
400 
401 void ASTDeclWriter::VisitEnumConstantDecl(EnumConstantDecl *D) {
402   VisitValueDecl(D);
403   Record.push_back(D->getInitExpr()? 1 : 0);
404   if (D->getInitExpr())
405     Writer.AddStmt(D->getInitExpr());
406   Writer.AddAPSInt(D->getInitVal(), Record);
407 
408   Code = serialization::DECL_ENUM_CONSTANT;
409 }
410 
411 void ASTDeclWriter::VisitDeclaratorDecl(DeclaratorDecl *D) {
412   VisitValueDecl(D);
413   Writer.AddSourceLocation(D->getInnerLocStart(), Record);
414   Record.push_back(D->hasExtInfo());
415   if (D->hasExtInfo())
416     Writer.AddQualifierInfo(*D->getExtInfo(), Record);
417 }
418 
419 void ASTDeclWriter::VisitFunctionDecl(FunctionDecl *D) {
420   VisitRedeclarable(D);
421   VisitDeclaratorDecl(D);
422   Writer.AddDeclarationNameLoc(D->DNLoc, D->getDeclName(), Record);
423   Record.push_back(D->getIdentifierNamespace());
424 
425   // FunctionDecl's body is handled last at ASTWriterDecl::Visit,
426   // after everything else is written.
427 
428   Record.push_back((int)D->SClass); // FIXME: stable encoding
429   Record.push_back(D->IsInline);
430   Record.push_back(D->IsInlineSpecified);
431   Record.push_back(D->IsVirtualAsWritten);
432   Record.push_back(D->IsPure);
433   Record.push_back(D->HasInheritedPrototype);
434   Record.push_back(D->HasWrittenPrototype);
435   Record.push_back(D->IsDeleted);
436   Record.push_back(D->IsTrivial);
437   Record.push_back(D->IsDefaulted);
438   Record.push_back(D->IsExplicitlyDefaulted);
439   Record.push_back(D->HasImplicitReturnZero);
440   Record.push_back(D->IsConstexpr);
441   Record.push_back(D->HasSkippedBody);
442   Record.push_back(D->IsLateTemplateParsed);
443   Record.push_back(D->getLinkageInternal());
444   Writer.AddSourceLocation(D->getLocEnd(), Record);
445 
446   Record.push_back(D->getTemplatedKind());
447   switch (D->getTemplatedKind()) {
448   case FunctionDecl::TK_NonTemplate:
449     break;
450   case FunctionDecl::TK_FunctionTemplate:
451     Writer.AddDeclRef(D->getDescribedFunctionTemplate(), Record);
452     break;
453   case FunctionDecl::TK_MemberSpecialization: {
454     MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo();
455     Writer.AddDeclRef(MemberInfo->getInstantiatedFrom(), Record);
456     Record.push_back(MemberInfo->getTemplateSpecializationKind());
457     Writer.AddSourceLocation(MemberInfo->getPointOfInstantiation(), Record);
458     break;
459   }
460   case FunctionDecl::TK_FunctionTemplateSpecialization: {
461     FunctionTemplateSpecializationInfo *
462       FTSInfo = D->getTemplateSpecializationInfo();
463     Writer.AddDeclRef(FTSInfo->getTemplate(), Record);
464     Record.push_back(FTSInfo->getTemplateSpecializationKind());
465 
466     // Template arguments.
467     Writer.AddTemplateArgumentList(FTSInfo->TemplateArguments, Record);
468 
469     // Template args as written.
470     Record.push_back(FTSInfo->TemplateArgumentsAsWritten != nullptr);
471     if (FTSInfo->TemplateArgumentsAsWritten) {
472       Record.push_back(FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs);
473       for (int i=0, e = FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs;
474              i!=e; ++i)
475         Writer.AddTemplateArgumentLoc((*FTSInfo->TemplateArgumentsAsWritten)[i],
476                                       Record);
477       Writer.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->LAngleLoc,
478                                Record);
479       Writer.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->RAngleLoc,
480                                Record);
481     }
482 
483     Writer.AddSourceLocation(FTSInfo->getPointOfInstantiation(), Record);
484 
485     if (D->isCanonicalDecl()) {
486       // Write the template that contains the specializations set. We will
487       // add a FunctionTemplateSpecializationInfo to it when reading.
488       Writer.AddDeclRef(FTSInfo->getTemplate()->getCanonicalDecl(), Record);
489     }
490     break;
491   }
492   case FunctionDecl::TK_DependentFunctionTemplateSpecialization: {
493     DependentFunctionTemplateSpecializationInfo *
494       DFTSInfo = D->getDependentSpecializationInfo();
495 
496     // Templates.
497     Record.push_back(DFTSInfo->getNumTemplates());
498     for (int i=0, e = DFTSInfo->getNumTemplates(); i != e; ++i)
499       Writer.AddDeclRef(DFTSInfo->getTemplate(i), Record);
500 
501     // Templates args.
502     Record.push_back(DFTSInfo->getNumTemplateArgs());
503     for (int i=0, e = DFTSInfo->getNumTemplateArgs(); i != e; ++i)
504       Writer.AddTemplateArgumentLoc(DFTSInfo->getTemplateArg(i), Record);
505     Writer.AddSourceLocation(DFTSInfo->getLAngleLoc(), Record);
506     Writer.AddSourceLocation(DFTSInfo->getRAngleLoc(), Record);
507     break;
508   }
509   }
510 
511   Record.push_back(D->param_size());
512   for (auto P : D->params())
513     Writer.AddDeclRef(P, Record);
514   Code = serialization::DECL_FUNCTION;
515 }
516 
517 void ASTDeclWriter::VisitObjCMethodDecl(ObjCMethodDecl *D) {
518   VisitNamedDecl(D);
519   // FIXME: convert to LazyStmtPtr?
520   // Unlike C/C++, method bodies will never be in header files.
521   bool HasBodyStuff = D->getBody() != nullptr     ||
522                       D->getSelfDecl() != nullptr || D->getCmdDecl() != nullptr;
523   Record.push_back(HasBodyStuff);
524   if (HasBodyStuff) {
525     Writer.AddStmt(D->getBody());
526     Writer.AddDeclRef(D->getSelfDecl(), Record);
527     Writer.AddDeclRef(D->getCmdDecl(), Record);
528   }
529   Record.push_back(D->isInstanceMethod());
530   Record.push_back(D->isVariadic());
531   Record.push_back(D->isPropertyAccessor());
532   Record.push_back(D->isDefined());
533   Record.push_back(D->IsOverriding);
534   Record.push_back(D->HasSkippedBody);
535 
536   Record.push_back(D->IsRedeclaration);
537   Record.push_back(D->HasRedeclaration);
538   if (D->HasRedeclaration) {
539     assert(Context.getObjCMethodRedeclaration(D));
540     Writer.AddDeclRef(Context.getObjCMethodRedeclaration(D), Record);
541   }
542 
543   // FIXME: stable encoding for @required/@optional
544   Record.push_back(D->getImplementationControl());
545   // FIXME: stable encoding for in/out/inout/bycopy/byref/oneway/nullability
546   Record.push_back(D->getObjCDeclQualifier());
547   Record.push_back(D->hasRelatedResultType());
548   Writer.AddTypeRef(D->getReturnType(), Record);
549   Writer.AddTypeSourceInfo(D->getReturnTypeSourceInfo(), Record);
550   Writer.AddSourceLocation(D->getLocEnd(), Record);
551   Record.push_back(D->param_size());
552   for (const auto *P : D->params())
553     Writer.AddDeclRef(P, Record);
554 
555   Record.push_back(D->SelLocsKind);
556   unsigned NumStoredSelLocs = D->getNumStoredSelLocs();
557   SourceLocation *SelLocs = D->getStoredSelLocs();
558   Record.push_back(NumStoredSelLocs);
559   for (unsigned i = 0; i != NumStoredSelLocs; ++i)
560     Writer.AddSourceLocation(SelLocs[i], Record);
561 
562   Code = serialization::DECL_OBJC_METHOD;
563 }
564 
565 void ASTDeclWriter::VisitObjCContainerDecl(ObjCContainerDecl *D) {
566   VisitNamedDecl(D);
567   Writer.AddSourceLocation(D->getAtStartLoc(), Record);
568   Writer.AddSourceRange(D->getAtEndRange(), Record);
569   // Abstract class (no need to define a stable serialization::DECL code).
570 }
571 
572 void ASTDeclWriter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
573   VisitRedeclarable(D);
574   VisitObjCContainerDecl(D);
575   Writer.AddTypeRef(QualType(D->getTypeForDecl(), 0), Record);
576 
577   Record.push_back(D->isThisDeclarationADefinition());
578   if (D->isThisDeclarationADefinition()) {
579     // Write the DefinitionData
580     ObjCInterfaceDecl::DefinitionData &Data = D->data();
581 
582     Writer.AddDeclRef(D->getSuperClass(), Record);
583     Writer.AddSourceLocation(D->getSuperClassLoc(), Record);
584     Writer.AddSourceLocation(D->getEndOfDefinitionLoc(), Record);
585     Record.push_back(Data.HasDesignatedInitializers);
586 
587     // Write out the protocols that are directly referenced by the @interface.
588     Record.push_back(Data.ReferencedProtocols.size());
589     for (const auto *P : D->protocols())
590       Writer.AddDeclRef(P, Record);
591     for (const auto &PL : D->protocol_locs())
592       Writer.AddSourceLocation(PL, Record);
593 
594     // Write out the protocols that are transitively referenced.
595     Record.push_back(Data.AllReferencedProtocols.size());
596     for (ObjCList<ObjCProtocolDecl>::iterator
597               P = Data.AllReferencedProtocols.begin(),
598            PEnd = Data.AllReferencedProtocols.end();
599          P != PEnd; ++P)
600       Writer.AddDeclRef(*P, Record);
601 
602 
603     if (ObjCCategoryDecl *Cat = D->getCategoryListRaw()) {
604       // Ensure that we write out the set of categories for this class.
605       Writer.ObjCClassesWithCategories.insert(D);
606 
607       // Make sure that the categories get serialized.
608       for (; Cat; Cat = Cat->getNextClassCategoryRaw())
609         (void)Writer.GetDeclRef(Cat);
610     }
611   }
612 
613   Code = serialization::DECL_OBJC_INTERFACE;
614 }
615 
616 void ASTDeclWriter::VisitObjCIvarDecl(ObjCIvarDecl *D) {
617   VisitFieldDecl(D);
618   // FIXME: stable encoding for @public/@private/@protected/@package
619   Record.push_back(D->getAccessControl());
620   Record.push_back(D->getSynthesize());
621 
622   if (!D->hasAttrs() &&
623       !D->isImplicit() &&
624       !D->isUsed(false) &&
625       !D->isInvalidDecl() &&
626       !D->isReferenced() &&
627       !D->isModulePrivate() &&
628       !D->getBitWidth() &&
629       !D->hasExtInfo() &&
630       D->getDeclName())
631     AbbrevToUse = Writer.getDeclObjCIvarAbbrev();
632 
633   Code = serialization::DECL_OBJC_IVAR;
634 }
635 
636 void ASTDeclWriter::VisitObjCProtocolDecl(ObjCProtocolDecl *D) {
637   VisitRedeclarable(D);
638   VisitObjCContainerDecl(D);
639 
640   Record.push_back(D->isThisDeclarationADefinition());
641   if (D->isThisDeclarationADefinition()) {
642     Record.push_back(D->protocol_size());
643     for (const auto *I : D->protocols())
644       Writer.AddDeclRef(I, Record);
645     for (const auto &PL : D->protocol_locs())
646       Writer.AddSourceLocation(PL, Record);
647   }
648 
649   Code = serialization::DECL_OBJC_PROTOCOL;
650 }
651 
652 void ASTDeclWriter::VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D) {
653   VisitFieldDecl(D);
654   Code = serialization::DECL_OBJC_AT_DEFS_FIELD;
655 }
656 
657 void ASTDeclWriter::VisitObjCCategoryDecl(ObjCCategoryDecl *D) {
658   VisitObjCContainerDecl(D);
659   Writer.AddSourceLocation(D->getCategoryNameLoc(), Record);
660   Writer.AddSourceLocation(D->getIvarLBraceLoc(), Record);
661   Writer.AddSourceLocation(D->getIvarRBraceLoc(), Record);
662   Writer.AddDeclRef(D->getClassInterface(), Record);
663   Record.push_back(D->protocol_size());
664   for (const auto *I : D->protocols())
665     Writer.AddDeclRef(I, Record);
666   for (const auto &PL : D->protocol_locs())
667     Writer.AddSourceLocation(PL, Record);
668   Code = serialization::DECL_OBJC_CATEGORY;
669 }
670 
671 void ASTDeclWriter::VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D) {
672   VisitNamedDecl(D);
673   Writer.AddDeclRef(D->getClassInterface(), Record);
674   Code = serialization::DECL_OBJC_COMPATIBLE_ALIAS;
675 }
676 
677 void ASTDeclWriter::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
678   VisitNamedDecl(D);
679   Writer.AddSourceLocation(D->getAtLoc(), Record);
680   Writer.AddSourceLocation(D->getLParenLoc(), Record);
681   Writer.AddTypeRef(D->getType(), Record);
682   Writer.AddTypeSourceInfo(D->getTypeSourceInfo(), Record);
683   // FIXME: stable encoding
684   Record.push_back((unsigned)D->getPropertyAttributes());
685   Record.push_back((unsigned)D->getPropertyAttributesAsWritten());
686   // FIXME: stable encoding
687   Record.push_back((unsigned)D->getPropertyImplementation());
688   Writer.AddDeclarationName(D->getGetterName(), Record);
689   Writer.AddDeclarationName(D->getSetterName(), Record);
690   Writer.AddDeclRef(D->getGetterMethodDecl(), Record);
691   Writer.AddDeclRef(D->getSetterMethodDecl(), Record);
692   Writer.AddDeclRef(D->getPropertyIvarDecl(), Record);
693   Code = serialization::DECL_OBJC_PROPERTY;
694 }
695 
696 void ASTDeclWriter::VisitObjCImplDecl(ObjCImplDecl *D) {
697   VisitObjCContainerDecl(D);
698   Writer.AddDeclRef(D->getClassInterface(), Record);
699   // Abstract class (no need to define a stable serialization::DECL code).
700 }
701 
702 void ASTDeclWriter::VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D) {
703   VisitObjCImplDecl(D);
704   Writer.AddIdentifierRef(D->getIdentifier(), Record);
705   Writer.AddSourceLocation(D->getCategoryNameLoc(), Record);
706   Code = serialization::DECL_OBJC_CATEGORY_IMPL;
707 }
708 
709 void ASTDeclWriter::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
710   VisitObjCImplDecl(D);
711   Writer.AddDeclRef(D->getSuperClass(), Record);
712   Writer.AddSourceLocation(D->getSuperClassLoc(), Record);
713   Writer.AddSourceLocation(D->getIvarLBraceLoc(), Record);
714   Writer.AddSourceLocation(D->getIvarRBraceLoc(), Record);
715   Record.push_back(D->hasNonZeroConstructors());
716   Record.push_back(D->hasDestructors());
717   Record.push_back(D->NumIvarInitializers);
718   if (D->NumIvarInitializers)
719     Writer.AddCXXCtorInitializersRef(
720         llvm::makeArrayRef(D->init_begin(), D->init_end()), Record);
721   Code = serialization::DECL_OBJC_IMPLEMENTATION;
722 }
723 
724 void ASTDeclWriter::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
725   VisitDecl(D);
726   Writer.AddSourceLocation(D->getLocStart(), Record);
727   Writer.AddDeclRef(D->getPropertyDecl(), Record);
728   Writer.AddDeclRef(D->getPropertyIvarDecl(), Record);
729   Writer.AddSourceLocation(D->getPropertyIvarDeclLoc(), Record);
730   Writer.AddStmt(D->getGetterCXXConstructor());
731   Writer.AddStmt(D->getSetterCXXAssignment());
732   Code = serialization::DECL_OBJC_PROPERTY_IMPL;
733 }
734 
735 void ASTDeclWriter::VisitFieldDecl(FieldDecl *D) {
736   VisitDeclaratorDecl(D);
737   Record.push_back(D->isMutable());
738   if (D->InitStorage.getInt() == FieldDecl::ISK_BitWidthOrNothing &&
739       D->InitStorage.getPointer() == nullptr) {
740     Record.push_back(0);
741   } else if (D->InitStorage.getInt() == FieldDecl::ISK_CapturedVLAType) {
742     Record.push_back(D->InitStorage.getInt() + 1);
743     Writer.AddTypeRef(
744         QualType(static_cast<Type *>(D->InitStorage.getPointer()), 0),
745         Record);
746   } else {
747     Record.push_back(D->InitStorage.getInt() + 1);
748     Writer.AddStmt(static_cast<Expr *>(D->InitStorage.getPointer()));
749   }
750   if (!D->getDeclName())
751     Writer.AddDeclRef(Context.getInstantiatedFromUnnamedFieldDecl(D), Record);
752 
753   if (!D->hasAttrs() &&
754       !D->isImplicit() &&
755       !D->isUsed(false) &&
756       !D->isInvalidDecl() &&
757       !D->isReferenced() &&
758       !D->isTopLevelDeclInObjCContainer() &&
759       !D->isModulePrivate() &&
760       !D->getBitWidth() &&
761       !D->hasInClassInitializer() &&
762       !D->hasExtInfo() &&
763       !ObjCIvarDecl::classofKind(D->getKind()) &&
764       !ObjCAtDefsFieldDecl::classofKind(D->getKind()) &&
765       D->getDeclName())
766     AbbrevToUse = Writer.getDeclFieldAbbrev();
767 
768   Code = serialization::DECL_FIELD;
769 }
770 
771 void ASTDeclWriter::VisitMSPropertyDecl(MSPropertyDecl *D) {
772   VisitDeclaratorDecl(D);
773   Writer.AddIdentifierRef(D->getGetterId(), Record);
774   Writer.AddIdentifierRef(D->getSetterId(), Record);
775   Code = serialization::DECL_MS_PROPERTY;
776 }
777 
778 void ASTDeclWriter::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
779   VisitValueDecl(D);
780   Record.push_back(D->getChainingSize());
781 
782   for (const auto *P : D->chain())
783     Writer.AddDeclRef(P, Record);
784   Code = serialization::DECL_INDIRECTFIELD;
785 }
786 
787 void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
788   VisitRedeclarable(D);
789   VisitDeclaratorDecl(D);
790   Record.push_back(D->getStorageClass());
791   Record.push_back(D->getTSCSpec());
792   Record.push_back(D->getInitStyle());
793   if (!isa<ParmVarDecl>(D)) {
794     Record.push_back(D->isExceptionVariable());
795     Record.push_back(D->isNRVOVariable());
796     Record.push_back(D->isCXXForRangeDecl());
797     Record.push_back(D->isARCPseudoStrong());
798     Record.push_back(D->isConstexpr());
799     Record.push_back(D->isInitCapture());
800     Record.push_back(D->isPreviousDeclInSameBlockScope());
801   }
802   Record.push_back(D->getLinkageInternal());
803 
804   if (D->getInit()) {
805     Record.push_back(!D->isInitKnownICE() ? 1 : (D->isInitICE() ? 3 : 2));
806     Writer.AddStmt(D->getInit());
807   } else {
808     Record.push_back(0);
809   }
810 
811   enum {
812     VarNotTemplate = 0, VarTemplate, StaticDataMemberSpecialization
813   };
814   if (VarTemplateDecl *TemplD = D->getDescribedVarTemplate()) {
815     Record.push_back(VarTemplate);
816     Writer.AddDeclRef(TemplD, Record);
817   } else if (MemberSpecializationInfo *SpecInfo
818                = D->getMemberSpecializationInfo()) {
819     Record.push_back(StaticDataMemberSpecialization);
820     Writer.AddDeclRef(SpecInfo->getInstantiatedFrom(), Record);
821     Record.push_back(SpecInfo->getTemplateSpecializationKind());
822     Writer.AddSourceLocation(SpecInfo->getPointOfInstantiation(), Record);
823   } else {
824     Record.push_back(VarNotTemplate);
825   }
826 
827   if (!D->hasAttrs() &&
828       !D->isImplicit() &&
829       !D->isUsed(false) &&
830       !D->isInvalidDecl() &&
831       !D->isReferenced() &&
832       !D->isTopLevelDeclInObjCContainer() &&
833       D->getAccess() == AS_none &&
834       !D->isModulePrivate() &&
835       !needsAnonymousDeclarationNumber(D) &&
836       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
837       !D->hasExtInfo() &&
838       D->getFirstDecl() == D->getMostRecentDecl() &&
839       D->getInitStyle() == VarDecl::CInit &&
840       D->getInit() == nullptr &&
841       !isa<ParmVarDecl>(D) &&
842       !isa<VarTemplateSpecializationDecl>(D) &&
843       !D->isConstexpr() &&
844       !D->isInitCapture() &&
845       !D->isPreviousDeclInSameBlockScope() &&
846       !D->getMemberSpecializationInfo())
847     AbbrevToUse = Writer.getDeclVarAbbrev();
848 
849   Code = serialization::DECL_VAR;
850 }
851 
852 void ASTDeclWriter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
853   VisitVarDecl(D);
854   Code = serialization::DECL_IMPLICIT_PARAM;
855 }
856 
857 void ASTDeclWriter::VisitParmVarDecl(ParmVarDecl *D) {
858   VisitVarDecl(D);
859   Record.push_back(D->isObjCMethodParameter());
860   Record.push_back(D->getFunctionScopeDepth());
861   Record.push_back(D->getFunctionScopeIndex());
862   Record.push_back(D->getObjCDeclQualifier()); // FIXME: stable encoding
863   Record.push_back(D->isKNRPromoted());
864   Record.push_back(D->hasInheritedDefaultArg());
865   Record.push_back(D->hasUninstantiatedDefaultArg());
866   if (D->hasUninstantiatedDefaultArg())
867     Writer.AddStmt(D->getUninstantiatedDefaultArg());
868   Code = serialization::DECL_PARM_VAR;
869 
870   assert(!D->isARCPseudoStrong()); // can be true of ImplicitParamDecl
871 
872   // If the assumptions about the DECL_PARM_VAR abbrev are true, use it.  Here
873   // we dynamically check for the properties that we optimize for, but don't
874   // know are true of all PARM_VAR_DECLs.
875   if (!D->hasAttrs() &&
876       !D->hasExtInfo() &&
877       !D->isImplicit() &&
878       !D->isUsed(false) &&
879       !D->isInvalidDecl() &&
880       !D->isReferenced() &&
881       D->getAccess() == AS_none &&
882       !D->isModulePrivate() &&
883       D->getStorageClass() == 0 &&
884       D->getInitStyle() == VarDecl::CInit && // Can params have anything else?
885       D->getFunctionScopeDepth() == 0 &&
886       D->getObjCDeclQualifier() == 0 &&
887       !D->isKNRPromoted() &&
888       !D->hasInheritedDefaultArg() &&
889       D->getInit() == nullptr &&
890       !D->hasUninstantiatedDefaultArg())  // No default expr.
891     AbbrevToUse = Writer.getDeclParmVarAbbrev();
892 
893   // Check things we know are true of *every* PARM_VAR_DECL, which is more than
894   // just us assuming it.
895   assert(!D->getTSCSpec() && "PARM_VAR_DECL can't use TLS");
896   assert(D->getAccess() == AS_none && "PARM_VAR_DECL can't be public/private");
897   assert(!D->isExceptionVariable() && "PARM_VAR_DECL can't be exception var");
898   assert(D->getPreviousDecl() == nullptr && "PARM_VAR_DECL can't be redecl");
899   assert(!D->isStaticDataMember() &&
900          "PARM_VAR_DECL can't be static data member");
901 }
902 
903 void ASTDeclWriter::VisitFileScopeAsmDecl(FileScopeAsmDecl *D) {
904   VisitDecl(D);
905   Writer.AddStmt(D->getAsmString());
906   Writer.AddSourceLocation(D->getRParenLoc(), Record);
907   Code = serialization::DECL_FILE_SCOPE_ASM;
908 }
909 
910 void ASTDeclWriter::VisitEmptyDecl(EmptyDecl *D) {
911   VisitDecl(D);
912   Code = serialization::DECL_EMPTY;
913 }
914 
915 void ASTDeclWriter::VisitBlockDecl(BlockDecl *D) {
916   VisitDecl(D);
917   Writer.AddStmt(D->getBody());
918   Writer.AddTypeSourceInfo(D->getSignatureAsWritten(), Record);
919   Record.push_back(D->param_size());
920   for (FunctionDecl::param_iterator P = D->param_begin(), PEnd = D->param_end();
921        P != PEnd; ++P)
922     Writer.AddDeclRef(*P, Record);
923   Record.push_back(D->isVariadic());
924   Record.push_back(D->blockMissingReturnType());
925   Record.push_back(D->isConversionFromLambda());
926   Record.push_back(D->capturesCXXThis());
927   Record.push_back(D->getNumCaptures());
928   for (const auto &capture : D->captures()) {
929     Writer.AddDeclRef(capture.getVariable(), Record);
930 
931     unsigned flags = 0;
932     if (capture.isByRef()) flags |= 1;
933     if (capture.isNested()) flags |= 2;
934     if (capture.hasCopyExpr()) flags |= 4;
935     Record.push_back(flags);
936 
937     if (capture.hasCopyExpr()) Writer.AddStmt(capture.getCopyExpr());
938   }
939 
940   Code = serialization::DECL_BLOCK;
941 }
942 
943 void ASTDeclWriter::VisitCapturedDecl(CapturedDecl *CD) {
944   Record.push_back(CD->getNumParams());
945   VisitDecl(CD);
946   Record.push_back(CD->getContextParamPosition());
947   Record.push_back(CD->isNothrow() ? 1 : 0);
948   // Body is stored by VisitCapturedStmt.
949   for (unsigned I = 0; I < CD->getNumParams(); ++I)
950     Writer.AddDeclRef(CD->getParam(I), Record);
951   Code = serialization::DECL_CAPTURED;
952 }
953 
954 void ASTDeclWriter::VisitLinkageSpecDecl(LinkageSpecDecl *D) {
955   VisitDecl(D);
956   Record.push_back(D->getLanguage());
957   Writer.AddSourceLocation(D->getExternLoc(), Record);
958   Writer.AddSourceLocation(D->getRBraceLoc(), Record);
959   Code = serialization::DECL_LINKAGE_SPEC;
960 }
961 
962 void ASTDeclWriter::VisitLabelDecl(LabelDecl *D) {
963   VisitNamedDecl(D);
964   Writer.AddSourceLocation(D->getLocStart(), Record);
965   Code = serialization::DECL_LABEL;
966 }
967 
968 
969 void ASTDeclWriter::VisitNamespaceDecl(NamespaceDecl *D) {
970   VisitRedeclarable(D);
971   VisitNamedDecl(D);
972   Record.push_back(D->isInline());
973   Writer.AddSourceLocation(D->getLocStart(), Record);
974   Writer.AddSourceLocation(D->getRBraceLoc(), Record);
975 
976   if (D->isOriginalNamespace())
977     Writer.AddDeclRef(D->getAnonymousNamespace(), Record);
978   Code = serialization::DECL_NAMESPACE;
979 
980   if (Writer.hasChain() && !D->isOriginalNamespace() &&
981       D->getOriginalNamespace()->isFromASTFile()) {
982     NamespaceDecl *NS = D->getOriginalNamespace();
983     Writer.UpdatedDeclContexts.insert(NS);
984 
985     // Make sure all visible decls are written. They will be recorded later. We
986     // do this using a side data structure so we can sort the names into
987     // a deterministic order.
988     StoredDeclsMap *Map = NS->buildLookup();
989     SmallVector<std::pair<DeclarationName, DeclContext::lookup_result>, 16>
990         LookupResults;
991     LookupResults.reserve(Map->size());
992     for (auto &Entry : *Map)
993       LookupResults.push_back(
994           std::make_pair(Entry.first, Entry.second.getLookupResult()));
995 
996     std::sort(LookupResults.begin(), LookupResults.end(), llvm::less_first());
997     for (auto &NameAndResult : LookupResults) {
998       DeclarationName Name = NameAndResult.first;
999       DeclContext::lookup_result Result = NameAndResult.second;
1000       if (Name.getNameKind() == DeclarationName::CXXConstructorName ||
1001           Name.getNameKind() == DeclarationName::CXXConversionFunctionName) {
1002         // We have to work around a name lookup bug here where negative lookup
1003         // results for these names get cached in namespace lookup tables.
1004         assert(Result.empty() && "Cannot have a constructor or conversion "
1005                                  "function name in a namespace!");
1006         continue;
1007       }
1008 
1009       for (NamedDecl *ND : Result)
1010         Writer.GetDeclRef(ND);
1011     }
1012   }
1013 
1014   if (Writer.hasChain() && D->isAnonymousNamespace() &&
1015       D == D->getMostRecentDecl()) {
1016     // This is a most recent reopening of the anonymous namespace. If its parent
1017     // is in a previous PCH (or is the TU), mark that parent for update, because
1018     // the original namespace always points to the latest re-opening of its
1019     // anonymous namespace.
1020     Decl *Parent = cast<Decl>(
1021         D->getParent()->getRedeclContext()->getPrimaryContext());
1022     if (Parent->isFromASTFile() || isa<TranslationUnitDecl>(Parent)) {
1023       Writer.DeclUpdates[Parent].push_back(
1024           ASTWriter::DeclUpdate(UPD_CXX_ADDED_ANONYMOUS_NAMESPACE, D));
1025     }
1026   }
1027 }
1028 
1029 void ASTDeclWriter::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
1030   VisitRedeclarable(D);
1031   VisitNamedDecl(D);
1032   Writer.AddSourceLocation(D->getNamespaceLoc(), Record);
1033   Writer.AddSourceLocation(D->getTargetNameLoc(), Record);
1034   Writer.AddNestedNameSpecifierLoc(D->getQualifierLoc(), Record);
1035   Writer.AddDeclRef(D->getNamespace(), Record);
1036   Code = serialization::DECL_NAMESPACE_ALIAS;
1037 }
1038 
1039 void ASTDeclWriter::VisitUsingDecl(UsingDecl *D) {
1040   VisitNamedDecl(D);
1041   Writer.AddSourceLocation(D->getUsingLoc(), Record);
1042   Writer.AddNestedNameSpecifierLoc(D->getQualifierLoc(), Record);
1043   Writer.AddDeclarationNameLoc(D->DNLoc, D->getDeclName(), Record);
1044   Writer.AddDeclRef(D->FirstUsingShadow.getPointer(), Record);
1045   Record.push_back(D->hasTypename());
1046   Writer.AddDeclRef(Context.getInstantiatedFromUsingDecl(D), Record);
1047   Code = serialization::DECL_USING;
1048 }
1049 
1050 void ASTDeclWriter::VisitUsingShadowDecl(UsingShadowDecl *D) {
1051   VisitRedeclarable(D);
1052   VisitNamedDecl(D);
1053   Writer.AddDeclRef(D->getTargetDecl(), Record);
1054   Writer.AddDeclRef(D->UsingOrNextShadow, Record);
1055   Writer.AddDeclRef(Context.getInstantiatedFromUsingShadowDecl(D), Record);
1056   Code = serialization::DECL_USING_SHADOW;
1057 }
1058 
1059 void ASTDeclWriter::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1060   VisitNamedDecl(D);
1061   Writer.AddSourceLocation(D->getUsingLoc(), Record);
1062   Writer.AddSourceLocation(D->getNamespaceKeyLocation(), Record);
1063   Writer.AddNestedNameSpecifierLoc(D->getQualifierLoc(), Record);
1064   Writer.AddDeclRef(D->getNominatedNamespace(), Record);
1065   Writer.AddDeclRef(dyn_cast<Decl>(D->getCommonAncestor()), Record);
1066   Code = serialization::DECL_USING_DIRECTIVE;
1067 }
1068 
1069 void ASTDeclWriter::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1070   VisitValueDecl(D);
1071   Writer.AddSourceLocation(D->getUsingLoc(), Record);
1072   Writer.AddNestedNameSpecifierLoc(D->getQualifierLoc(), Record);
1073   Writer.AddDeclarationNameLoc(D->DNLoc, D->getDeclName(), Record);
1074   Code = serialization::DECL_UNRESOLVED_USING_VALUE;
1075 }
1076 
1077 void ASTDeclWriter::VisitUnresolvedUsingTypenameDecl(
1078                                                UnresolvedUsingTypenameDecl *D) {
1079   VisitTypeDecl(D);
1080   Writer.AddSourceLocation(D->getTypenameLoc(), Record);
1081   Writer.AddNestedNameSpecifierLoc(D->getQualifierLoc(), Record);
1082   Code = serialization::DECL_UNRESOLVED_USING_TYPENAME;
1083 }
1084 
1085 void ASTDeclWriter::VisitCXXRecordDecl(CXXRecordDecl *D) {
1086   VisitRecordDecl(D);
1087 
1088   enum {
1089     CXXRecNotTemplate = 0, CXXRecTemplate, CXXRecMemberSpecialization
1090   };
1091   if (ClassTemplateDecl *TemplD = D->getDescribedClassTemplate()) {
1092     Record.push_back(CXXRecTemplate);
1093     Writer.AddDeclRef(TemplD, Record);
1094   } else if (MemberSpecializationInfo *MSInfo
1095                = D->getMemberSpecializationInfo()) {
1096     Record.push_back(CXXRecMemberSpecialization);
1097     Writer.AddDeclRef(MSInfo->getInstantiatedFrom(), Record);
1098     Record.push_back(MSInfo->getTemplateSpecializationKind());
1099     Writer.AddSourceLocation(MSInfo->getPointOfInstantiation(), Record);
1100   } else {
1101     Record.push_back(CXXRecNotTemplate);
1102   }
1103 
1104   Record.push_back(D->isThisDeclarationADefinition());
1105   if (D->isThisDeclarationADefinition())
1106     Writer.AddCXXDefinitionData(D, Record);
1107 
1108   // Store (what we currently believe to be) the key function to avoid
1109   // deserializing every method so we can compute it.
1110   if (D->IsCompleteDefinition)
1111     Writer.AddDeclRef(Context.getCurrentKeyFunction(D), Record);
1112 
1113   Code = serialization::DECL_CXX_RECORD;
1114 }
1115 
1116 void ASTDeclWriter::VisitCXXMethodDecl(CXXMethodDecl *D) {
1117   VisitFunctionDecl(D);
1118   if (D->isCanonicalDecl()) {
1119     Record.push_back(D->size_overridden_methods());
1120     for (CXXMethodDecl::method_iterator
1121            I = D->begin_overridden_methods(), E = D->end_overridden_methods();
1122            I != E; ++I)
1123       Writer.AddDeclRef(*I, Record);
1124   } else {
1125     // We only need to record overridden methods once for the canonical decl.
1126     Record.push_back(0);
1127   }
1128 
1129   if (D->getFirstDecl() == D->getMostRecentDecl() &&
1130       !D->isInvalidDecl() &&
1131       !D->hasAttrs() &&
1132       !D->isTopLevelDeclInObjCContainer() &&
1133       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1134       !D->hasExtInfo() &&
1135       !D->hasInheritedPrototype() &&
1136       D->hasWrittenPrototype())
1137     AbbrevToUse = Writer.getDeclCXXMethodAbbrev();
1138 
1139   Code = serialization::DECL_CXX_METHOD;
1140 }
1141 
1142 void ASTDeclWriter::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1143   VisitCXXMethodDecl(D);
1144 
1145   Writer.AddDeclRef(D->getInheritedConstructor(), Record);
1146   Record.push_back(D->IsExplicitSpecified);
1147 
1148   Code = serialization::DECL_CXX_CONSTRUCTOR;
1149 }
1150 
1151 void ASTDeclWriter::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1152   VisitCXXMethodDecl(D);
1153 
1154   Writer.AddDeclRef(D->getOperatorDelete(), Record);
1155 
1156   Code = serialization::DECL_CXX_DESTRUCTOR;
1157 }
1158 
1159 void ASTDeclWriter::VisitCXXConversionDecl(CXXConversionDecl *D) {
1160   VisitCXXMethodDecl(D);
1161   Record.push_back(D->IsExplicitSpecified);
1162   Code = serialization::DECL_CXX_CONVERSION;
1163 }
1164 
1165 void ASTDeclWriter::VisitImportDecl(ImportDecl *D) {
1166   VisitDecl(D);
1167   Record.push_back(Writer.getSubmoduleID(D->getImportedModule()));
1168   ArrayRef<SourceLocation> IdentifierLocs = D->getIdentifierLocs();
1169   Record.push_back(!IdentifierLocs.empty());
1170   if (IdentifierLocs.empty()) {
1171     Writer.AddSourceLocation(D->getLocEnd(), Record);
1172     Record.push_back(1);
1173   } else {
1174     for (unsigned I = 0, N = IdentifierLocs.size(); I != N; ++I)
1175       Writer.AddSourceLocation(IdentifierLocs[I], Record);
1176     Record.push_back(IdentifierLocs.size());
1177   }
1178   // Note: the number of source locations must always be the last element in
1179   // the record.
1180   Code = serialization::DECL_IMPORT;
1181 }
1182 
1183 void ASTDeclWriter::VisitAccessSpecDecl(AccessSpecDecl *D) {
1184   VisitDecl(D);
1185   Writer.AddSourceLocation(D->getColonLoc(), Record);
1186   Code = serialization::DECL_ACCESS_SPEC;
1187 }
1188 
1189 void ASTDeclWriter::VisitFriendDecl(FriendDecl *D) {
1190   // Record the number of friend type template parameter lists here
1191   // so as to simplify memory allocation during deserialization.
1192   Record.push_back(D->NumTPLists);
1193   VisitDecl(D);
1194   bool hasFriendDecl = D->Friend.is<NamedDecl*>();
1195   Record.push_back(hasFriendDecl);
1196   if (hasFriendDecl)
1197     Writer.AddDeclRef(D->getFriendDecl(), Record);
1198   else
1199     Writer.AddTypeSourceInfo(D->getFriendType(), Record);
1200   for (unsigned i = 0; i < D->NumTPLists; ++i)
1201     Writer.AddTemplateParameterList(D->getFriendTypeTemplateParameterList(i),
1202                                     Record);
1203   Writer.AddDeclRef(D->getNextFriend(), Record);
1204   Record.push_back(D->UnsupportedFriend);
1205   Writer.AddSourceLocation(D->FriendLoc, Record);
1206   Code = serialization::DECL_FRIEND;
1207 }
1208 
1209 void ASTDeclWriter::VisitFriendTemplateDecl(FriendTemplateDecl *D) {
1210   VisitDecl(D);
1211   Record.push_back(D->getNumTemplateParameters());
1212   for (unsigned i = 0, e = D->getNumTemplateParameters(); i != e; ++i)
1213     Writer.AddTemplateParameterList(D->getTemplateParameterList(i), Record);
1214   Record.push_back(D->getFriendDecl() != nullptr);
1215   if (D->getFriendDecl())
1216     Writer.AddDeclRef(D->getFriendDecl(), Record);
1217   else
1218     Writer.AddTypeSourceInfo(D->getFriendType(), Record);
1219   Writer.AddSourceLocation(D->getFriendLoc(), Record);
1220   Code = serialization::DECL_FRIEND_TEMPLATE;
1221 }
1222 
1223 void ASTDeclWriter::VisitTemplateDecl(TemplateDecl *D) {
1224   VisitNamedDecl(D);
1225 
1226   Writer.AddDeclRef(D->getTemplatedDecl(), Record);
1227   Writer.AddTemplateParameterList(D->getTemplateParameters(), Record);
1228 }
1229 
1230 void ASTDeclWriter::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
1231   VisitRedeclarable(D);
1232 
1233   // Emit data to initialize CommonOrPrev before VisitTemplateDecl so that
1234   // getCommonPtr() can be used while this is still initializing.
1235   if (D->isFirstDecl()) {
1236     // This declaration owns the 'common' pointer, so serialize that data now.
1237     Writer.AddDeclRef(D->getInstantiatedFromMemberTemplate(), Record);
1238     if (D->getInstantiatedFromMemberTemplate())
1239       Record.push_back(D->isMemberSpecialization());
1240   }
1241 
1242   VisitTemplateDecl(D);
1243   Record.push_back(D->getIdentifierNamespace());
1244 }
1245 
1246 void ASTDeclWriter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
1247   VisitRedeclarableTemplateDecl(D);
1248 
1249   if (D->isFirstDecl())
1250     AddTemplateSpecializations(D);
1251   Code = serialization::DECL_CLASS_TEMPLATE;
1252 }
1253 
1254 void ASTDeclWriter::VisitClassTemplateSpecializationDecl(
1255                                            ClassTemplateSpecializationDecl *D) {
1256   VisitCXXRecordDecl(D);
1257 
1258   llvm::PointerUnion<ClassTemplateDecl *,
1259                      ClassTemplatePartialSpecializationDecl *> InstFrom
1260     = D->getSpecializedTemplateOrPartial();
1261   if (Decl *InstFromD = InstFrom.dyn_cast<ClassTemplateDecl *>()) {
1262     Writer.AddDeclRef(InstFromD, Record);
1263   } else {
1264     Writer.AddDeclRef(InstFrom.get<ClassTemplatePartialSpecializationDecl *>(),
1265                       Record);
1266     Writer.AddTemplateArgumentList(&D->getTemplateInstantiationArgs(), Record);
1267   }
1268 
1269   Writer.AddTemplateArgumentList(&D->getTemplateArgs(), Record);
1270   Writer.AddSourceLocation(D->getPointOfInstantiation(), Record);
1271   Record.push_back(D->getSpecializationKind());
1272   Record.push_back(D->isCanonicalDecl());
1273 
1274   if (D->isCanonicalDecl()) {
1275     // When reading, we'll add it to the folding set of the following template.
1276     Writer.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl(), Record);
1277   }
1278 
1279   // Explicit info.
1280   Writer.AddTypeSourceInfo(D->getTypeAsWritten(), Record);
1281   if (D->getTypeAsWritten()) {
1282     Writer.AddSourceLocation(D->getExternLoc(), Record);
1283     Writer.AddSourceLocation(D->getTemplateKeywordLoc(), Record);
1284   }
1285 
1286   Code = serialization::DECL_CLASS_TEMPLATE_SPECIALIZATION;
1287 }
1288 
1289 void ASTDeclWriter::VisitClassTemplatePartialSpecializationDecl(
1290                                     ClassTemplatePartialSpecializationDecl *D) {
1291   VisitClassTemplateSpecializationDecl(D);
1292 
1293   Writer.AddTemplateParameterList(D->getTemplateParameters(), Record);
1294   Writer.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten(), Record);
1295 
1296   // These are read/set from/to the first declaration.
1297   if (D->getPreviousDecl() == nullptr) {
1298     Writer.AddDeclRef(D->getInstantiatedFromMember(), Record);
1299     Record.push_back(D->isMemberSpecialization());
1300   }
1301 
1302   Code = serialization::DECL_CLASS_TEMPLATE_PARTIAL_SPECIALIZATION;
1303 }
1304 
1305 void ASTDeclWriter::VisitVarTemplateDecl(VarTemplateDecl *D) {
1306   VisitRedeclarableTemplateDecl(D);
1307 
1308   if (D->isFirstDecl())
1309     AddTemplateSpecializations(D);
1310   Code = serialization::DECL_VAR_TEMPLATE;
1311 }
1312 
1313 void ASTDeclWriter::VisitVarTemplateSpecializationDecl(
1314     VarTemplateSpecializationDecl *D) {
1315   VisitVarDecl(D);
1316 
1317   llvm::PointerUnion<VarTemplateDecl *, VarTemplatePartialSpecializationDecl *>
1318   InstFrom = D->getSpecializedTemplateOrPartial();
1319   if (Decl *InstFromD = InstFrom.dyn_cast<VarTemplateDecl *>()) {
1320     Writer.AddDeclRef(InstFromD, Record);
1321   } else {
1322     Writer.AddDeclRef(InstFrom.get<VarTemplatePartialSpecializationDecl *>(),
1323                       Record);
1324     Writer.AddTemplateArgumentList(&D->getTemplateInstantiationArgs(), Record);
1325   }
1326 
1327   // Explicit info.
1328   Writer.AddTypeSourceInfo(D->getTypeAsWritten(), Record);
1329   if (D->getTypeAsWritten()) {
1330     Writer.AddSourceLocation(D->getExternLoc(), Record);
1331     Writer.AddSourceLocation(D->getTemplateKeywordLoc(), Record);
1332   }
1333 
1334   Writer.AddTemplateArgumentList(&D->getTemplateArgs(), Record);
1335   Writer.AddSourceLocation(D->getPointOfInstantiation(), Record);
1336   Record.push_back(D->getSpecializationKind());
1337   Record.push_back(D->isCanonicalDecl());
1338 
1339   if (D->isCanonicalDecl()) {
1340     // When reading, we'll add it to the folding set of the following template.
1341     Writer.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl(), Record);
1342   }
1343 
1344   Code = serialization::DECL_VAR_TEMPLATE_SPECIALIZATION;
1345 }
1346 
1347 void ASTDeclWriter::VisitVarTemplatePartialSpecializationDecl(
1348     VarTemplatePartialSpecializationDecl *D) {
1349   VisitVarTemplateSpecializationDecl(D);
1350 
1351   Writer.AddTemplateParameterList(D->getTemplateParameters(), Record);
1352   Writer.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten(), Record);
1353 
1354   // These are read/set from/to the first declaration.
1355   if (D->getPreviousDecl() == nullptr) {
1356     Writer.AddDeclRef(D->getInstantiatedFromMember(), Record);
1357     Record.push_back(D->isMemberSpecialization());
1358   }
1359 
1360   Code = serialization::DECL_VAR_TEMPLATE_PARTIAL_SPECIALIZATION;
1361 }
1362 
1363 void ASTDeclWriter::VisitClassScopeFunctionSpecializationDecl(
1364                                     ClassScopeFunctionSpecializationDecl *D) {
1365   VisitDecl(D);
1366   Writer.AddDeclRef(D->getSpecialization(), Record);
1367   Code = serialization::DECL_CLASS_SCOPE_FUNCTION_SPECIALIZATION;
1368 }
1369 
1370 
1371 void ASTDeclWriter::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
1372   VisitRedeclarableTemplateDecl(D);
1373 
1374   if (D->isFirstDecl())
1375     AddTemplateSpecializations(D);
1376   Code = serialization::DECL_FUNCTION_TEMPLATE;
1377 }
1378 
1379 void ASTDeclWriter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
1380   VisitTypeDecl(D);
1381 
1382   Record.push_back(D->wasDeclaredWithTypename());
1383 
1384   bool OwnsDefaultArg = D->hasDefaultArgument() &&
1385                         !D->defaultArgumentWasInherited();
1386   Record.push_back(OwnsDefaultArg);
1387   if (OwnsDefaultArg)
1388     Writer.AddTypeSourceInfo(D->getDefaultArgumentInfo(), Record);
1389 
1390   Code = serialization::DECL_TEMPLATE_TYPE_PARM;
1391 }
1392 
1393 void ASTDeclWriter::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
1394   // For an expanded parameter pack, record the number of expansion types here
1395   // so that it's easier for deserialization to allocate the right amount of
1396   // memory.
1397   if (D->isExpandedParameterPack())
1398     Record.push_back(D->getNumExpansionTypes());
1399 
1400   VisitDeclaratorDecl(D);
1401   // TemplateParmPosition.
1402   Record.push_back(D->getDepth());
1403   Record.push_back(D->getPosition());
1404 
1405   if (D->isExpandedParameterPack()) {
1406     for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1407       Writer.AddTypeRef(D->getExpansionType(I), Record);
1408       Writer.AddTypeSourceInfo(D->getExpansionTypeSourceInfo(I), Record);
1409     }
1410 
1411     Code = serialization::DECL_EXPANDED_NON_TYPE_TEMPLATE_PARM_PACK;
1412   } else {
1413     // Rest of NonTypeTemplateParmDecl.
1414     Record.push_back(D->isParameterPack());
1415     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1416                           !D->defaultArgumentWasInherited();
1417     Record.push_back(OwnsDefaultArg);
1418     if (OwnsDefaultArg)
1419       Writer.AddStmt(D->getDefaultArgument());
1420     Code = serialization::DECL_NON_TYPE_TEMPLATE_PARM;
1421   }
1422 }
1423 
1424 void ASTDeclWriter::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
1425   // For an expanded parameter pack, record the number of expansion types here
1426   // so that it's easier for deserialization to allocate the right amount of
1427   // memory.
1428   if (D->isExpandedParameterPack())
1429     Record.push_back(D->getNumExpansionTemplateParameters());
1430 
1431   VisitTemplateDecl(D);
1432   // TemplateParmPosition.
1433   Record.push_back(D->getDepth());
1434   Record.push_back(D->getPosition());
1435 
1436   if (D->isExpandedParameterPack()) {
1437     for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
1438          I != N; ++I)
1439       Writer.AddTemplateParameterList(D->getExpansionTemplateParameters(I),
1440                                       Record);
1441     Code = serialization::DECL_EXPANDED_TEMPLATE_TEMPLATE_PARM_PACK;
1442   } else {
1443     // Rest of TemplateTemplateParmDecl.
1444     Record.push_back(D->isParameterPack());
1445     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1446                           !D->defaultArgumentWasInherited();
1447     Record.push_back(OwnsDefaultArg);
1448     if (OwnsDefaultArg)
1449       Writer.AddTemplateArgumentLoc(D->getDefaultArgument(), Record);
1450     Code = serialization::DECL_TEMPLATE_TEMPLATE_PARM;
1451   }
1452 }
1453 
1454 void ASTDeclWriter::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
1455   VisitRedeclarableTemplateDecl(D);
1456   Code = serialization::DECL_TYPE_ALIAS_TEMPLATE;
1457 }
1458 
1459 void ASTDeclWriter::VisitStaticAssertDecl(StaticAssertDecl *D) {
1460   VisitDecl(D);
1461   Writer.AddStmt(D->getAssertExpr());
1462   Record.push_back(D->isFailed());
1463   Writer.AddStmt(D->getMessage());
1464   Writer.AddSourceLocation(D->getRParenLoc(), Record);
1465   Code = serialization::DECL_STATIC_ASSERT;
1466 }
1467 
1468 /// \brief Emit the DeclContext part of a declaration context decl.
1469 ///
1470 /// \param LexicalOffset the offset at which the DECL_CONTEXT_LEXICAL
1471 /// block for this declaration context is stored. May be 0 to indicate
1472 /// that there are no declarations stored within this context.
1473 ///
1474 /// \param VisibleOffset the offset at which the DECL_CONTEXT_VISIBLE
1475 /// block for this declaration context is stored. May be 0 to indicate
1476 /// that there are no declarations visible from this context. Note
1477 /// that this value will not be emitted for non-primary declaration
1478 /// contexts.
1479 void ASTDeclWriter::VisitDeclContext(DeclContext *DC, uint64_t LexicalOffset,
1480                                      uint64_t VisibleOffset) {
1481   Record.push_back(LexicalOffset);
1482   Record.push_back(VisibleOffset);
1483 }
1484 
1485 template <typename T>
1486 void ASTDeclWriter::VisitRedeclarable(Redeclarable<T> *D) {
1487   T *First = D->getFirstDecl();
1488   T *MostRecent = First->getMostRecentDecl();
1489   if (MostRecent != First) {
1490     assert(isRedeclarableDeclKind(static_cast<T *>(D)->getKind()) &&
1491            "Not considered redeclarable?");
1492 
1493     // There is more than one declaration of this entity, so we will need to
1494     // write a redeclaration chain.
1495     Writer.AddDeclRef(First, Record);
1496     Writer.Redeclarations.insert(First);
1497 
1498     auto *Previous = D->getPreviousDecl();
1499 
1500     // In a modules build, we can have imported declarations after a local
1501     // canonical declaration. If this is the first local declaration, emit
1502     // a list of all such imported declarations so that we can ensure they
1503     // are loaded before we are. This allows us to rebuild the redecl chain
1504     // in the right order on reload (all declarations imported by a module
1505     // should be before all declarations provided by that module).
1506     bool EmitImportedMergedCanonicalDecls = false;
1507     if (Context.getLangOpts().Modules && Writer.Chain) {
1508       auto *PreviousLocal = Previous;
1509       while (PreviousLocal && PreviousLocal->isFromASTFile())
1510         PreviousLocal = PreviousLocal->getPreviousDecl();
1511       if (!PreviousLocal)
1512         EmitImportedMergedCanonicalDecls = true;
1513     }
1514     if (EmitImportedMergedCanonicalDecls) {
1515       llvm::SmallMapVector<ModuleFile*, Decl*, 16> FirstInModule;
1516       for (auto *Redecl = MostRecent; Redecl;
1517            Redecl = Redecl->getPreviousDecl())
1518         if (Redecl->isFromASTFile())
1519           FirstInModule[Writer.Chain->getOwningModuleFile(Redecl)] = Redecl;
1520       // FIXME: If FirstInModule has entries for modules A and B, and B imports
1521       // A (directly or indirectly), we don't need to write the entry for A.
1522       Record.push_back(FirstInModule.size());
1523       for (auto I = FirstInModule.rbegin(), E = FirstInModule.rend();
1524            I != E; ++I)
1525         Writer.AddDeclRef(I->second, Record);
1526     } else
1527       Record.push_back(0);
1528 
1529     // Make sure that we serialize both the previous and the most-recent
1530     // declarations, which (transitively) ensures that all declarations in the
1531     // chain get serialized.
1532     //
1533     // FIXME: This is not correct; when we reach an imported declaration we
1534     // won't emit its previous declaration.
1535     (void)Writer.GetDeclRef(Previous);
1536     (void)Writer.GetDeclRef(MostRecent);
1537   } else {
1538     // We use the sentinel value 0 to indicate an only declaration.
1539     Record.push_back(0);
1540   }
1541 }
1542 
1543 void ASTDeclWriter::VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D) {
1544   Record.push_back(D->varlist_size());
1545   VisitDecl(D);
1546   for (auto *I : D->varlists())
1547     Writer.AddStmt(I);
1548   Code = serialization::DECL_OMP_THREADPRIVATE;
1549 }
1550 
1551 //===----------------------------------------------------------------------===//
1552 // ASTWriter Implementation
1553 //===----------------------------------------------------------------------===//
1554 
1555 void ASTWriter::WriteDeclAbbrevs() {
1556   using namespace llvm;
1557 
1558   BitCodeAbbrev *Abv;
1559 
1560   // Abbreviation for DECL_FIELD
1561   Abv = new BitCodeAbbrev();
1562   Abv->Add(BitCodeAbbrevOp(serialization::DECL_FIELD));
1563   // Decl
1564   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1565   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1566   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1567   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1568   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1569   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1570   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1571   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1572   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1573   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1574   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1575   // NamedDecl
1576   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1577   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1578   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1579   // ValueDecl
1580   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1581   // DeclaratorDecl
1582   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1583   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1584   // FieldDecl
1585   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1586   Abv->Add(BitCodeAbbrevOp(0));                       //getBitWidth
1587   // Type Source Info
1588   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1589   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1590   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1591   DeclFieldAbbrev = Stream.EmitAbbrev(Abv);
1592 
1593   // Abbreviation for DECL_OBJC_IVAR
1594   Abv = new BitCodeAbbrev();
1595   Abv->Add(BitCodeAbbrevOp(serialization::DECL_OBJC_IVAR));
1596   // Decl
1597   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1598   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1599   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1600   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1601   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1602   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1603   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1604   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1605   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1606   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1607   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1608   // NamedDecl
1609   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1610   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1611   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1612   // ValueDecl
1613   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1614   // DeclaratorDecl
1615   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1616   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1617   // FieldDecl
1618   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1619   Abv->Add(BitCodeAbbrevOp(0));                       //getBitWidth
1620   // ObjC Ivar
1621   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getAccessControl
1622   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getSynthesize
1623   // Type Source Info
1624   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1625   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1626   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1627   DeclObjCIvarAbbrev = Stream.EmitAbbrev(Abv);
1628 
1629   // Abbreviation for DECL_ENUM
1630   Abv = new BitCodeAbbrev();
1631   Abv->Add(BitCodeAbbrevOp(serialization::DECL_ENUM));
1632   // Redeclarable
1633   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1634   // Decl
1635   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1636   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1637   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1638   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1639   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1640   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1641   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1642   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1643   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1644   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1645   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1646   // NamedDecl
1647   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1648   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1649   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1650   // TypeDecl
1651   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1652   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1653   // TagDecl
1654   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
1655   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
1656   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
1657   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
1658   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
1659   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
1660   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1661   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
1662   // EnumDecl
1663   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddTypeRef
1664   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IntegerType
1665   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getPromotionType
1666   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumPositiveBits
1667   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumNegativeBits
1668   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScoped
1669   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScopedUsingClassTag
1670   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isFixed
1671   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InstantiatedMembEnum
1672   // DC
1673   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
1674   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
1675   DeclEnumAbbrev = Stream.EmitAbbrev(Abv);
1676 
1677   // Abbreviation for DECL_RECORD
1678   Abv = new BitCodeAbbrev();
1679   Abv->Add(BitCodeAbbrevOp(serialization::DECL_RECORD));
1680   // Redeclarable
1681   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1682   // Decl
1683   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1684   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1685   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1686   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1687   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1688   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1689   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1690   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1691   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1692   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1693   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1694   // NamedDecl
1695   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1696   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1697   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1698   // TypeDecl
1699   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1700   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1701   // TagDecl
1702   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
1703   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
1704   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
1705   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
1706   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
1707   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
1708   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1709   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
1710   // RecordDecl
1711   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // FlexibleArrayMember
1712   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // AnonymousStructUnion
1713   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasObjectMember
1714   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasVolatileMember
1715   // DC
1716   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
1717   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
1718   DeclRecordAbbrev = Stream.EmitAbbrev(Abv);
1719 
1720   // Abbreviation for DECL_PARM_VAR
1721   Abv = new BitCodeAbbrev();
1722   Abv->Add(BitCodeAbbrevOp(serialization::DECL_PARM_VAR));
1723   // Redeclarable
1724   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1725   // Decl
1726   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1727   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1728   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1729   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1730   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1731   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1732   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1733   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1734   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1735   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1736   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1737   // NamedDecl
1738   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1739   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1740   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1741   // ValueDecl
1742   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1743   // DeclaratorDecl
1744   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1745   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1746   // VarDecl
1747   Abv->Add(BitCodeAbbrevOp(0));                       // StorageClass
1748   Abv->Add(BitCodeAbbrevOp(0));                       // getTSCSpec
1749   Abv->Add(BitCodeAbbrevOp(0));                       // hasCXXDirectInitializer
1750   Abv->Add(BitCodeAbbrevOp(0));                       // Linkage
1751   Abv->Add(BitCodeAbbrevOp(0));                       // HasInit
1752   Abv->Add(BitCodeAbbrevOp(0));                   // HasMemberSpecializationInfo
1753   // ParmVarDecl
1754   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsObjCMethodParameter
1755   Abv->Add(BitCodeAbbrevOp(0));                       // ScopeDepth
1756   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ScopeIndex
1757   Abv->Add(BitCodeAbbrevOp(0));                       // ObjCDeclQualifier
1758   Abv->Add(BitCodeAbbrevOp(0));                       // KNRPromoted
1759   Abv->Add(BitCodeAbbrevOp(0));                       // HasInheritedDefaultArg
1760   Abv->Add(BitCodeAbbrevOp(0));                   // HasUninstantiatedDefaultArg
1761   // Type Source Info
1762   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1763   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1764   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1765   DeclParmVarAbbrev = Stream.EmitAbbrev(Abv);
1766 
1767   // Abbreviation for DECL_TYPEDEF
1768   Abv = new BitCodeAbbrev();
1769   Abv->Add(BitCodeAbbrevOp(serialization::DECL_TYPEDEF));
1770   // Redeclarable
1771   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1772   // Decl
1773   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1774   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1775   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1776   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1777   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1778   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isUsed
1779   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isReferenced
1780   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1781   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // C++ AccessSpecifier
1782   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1783   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1784   // NamedDecl
1785   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1786   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1787   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1788   // TypeDecl
1789   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1790   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1791   // TypedefDecl
1792   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1793   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1794   DeclTypedefAbbrev = Stream.EmitAbbrev(Abv);
1795 
1796   // Abbreviation for DECL_VAR
1797   Abv = new BitCodeAbbrev();
1798   Abv->Add(BitCodeAbbrevOp(serialization::DECL_VAR));
1799   // Redeclarable
1800   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1801   // Decl
1802   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1803   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1804   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1805   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1806   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1807   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1808   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1809   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1810   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1811   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1812   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1813   // NamedDecl
1814   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1815   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1816   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1817   // ValueDecl
1818   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1819   // DeclaratorDecl
1820   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1821   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1822   // VarDecl
1823   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // StorageClass
1824   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // getTSCSpec
1825   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // CXXDirectInitializer
1826   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isExceptionVariable
1827   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isNRVOVariable
1828   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCXXForRangeDecl
1829   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isARCPseudoStrong
1830   Abv->Add(BitCodeAbbrevOp(0));                         // isConstexpr
1831   Abv->Add(BitCodeAbbrevOp(0));                         // isInitCapture
1832   Abv->Add(BitCodeAbbrevOp(0));                         // isPrevDeclInSameScope
1833   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
1834   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // HasInit
1835   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // HasMemberSpecInfo
1836   // Type Source Info
1837   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1838   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1839   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1840   DeclVarAbbrev = Stream.EmitAbbrev(Abv);
1841 
1842   // Abbreviation for DECL_CXX_METHOD
1843   Abv = new BitCodeAbbrev();
1844   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CXX_METHOD));
1845   // RedeclarableDecl
1846   Abv->Add(BitCodeAbbrevOp(0));                         // CanonicalDecl
1847   // Decl
1848   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // DeclContext
1849   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalDeclContext
1850   Abv->Add(BitCodeAbbrevOp(0));                         // Invalid
1851   Abv->Add(BitCodeAbbrevOp(0));                         // HasAttrs
1852   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Implicit
1853   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Used
1854   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Referenced
1855   Abv->Add(BitCodeAbbrevOp(0));                         // InObjCContainer
1856   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // Access
1857   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ModulePrivate
1858   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SubmoduleID
1859   // NamedDecl
1860   Abv->Add(BitCodeAbbrevOp(DeclarationName::Identifier)); // NameKind
1861   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Identifier
1862   Abv->Add(BitCodeAbbrevOp(0));                         // AnonDeclNumber
1863   // ValueDecl
1864   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Type
1865   // DeclaratorDecl
1866   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InnerLocStart
1867   Abv->Add(BitCodeAbbrevOp(0));                         // HasExtInfo
1868   // FunctionDecl
1869   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 11)); // IDNS
1870   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // StorageClass
1871   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Inline
1872   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // InlineSpecified
1873   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // VirtualAsWritten
1874   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Pure
1875   Abv->Add(BitCodeAbbrevOp(0));                         // HasInheritedProto
1876   Abv->Add(BitCodeAbbrevOp(1));                         // HasWrittenProto
1877   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Deleted
1878   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Trivial
1879   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Defaulted
1880   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ExplicitlyDefaulted
1881   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ImplicitReturnZero
1882   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Constexpr
1883   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // SkippedBody
1884   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // LateParsed
1885   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
1886   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LocEnd
1887   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // TemplateKind
1888   // This Array slurps the rest of the record. Fortunately we want to encode
1889   // (nearly) all the remaining (variable number of) fields in the same way.
1890   //
1891   // This is the function template information if any, then
1892   //         NumParams and Params[] from FunctionDecl, and
1893   //         NumOverriddenMethods, OverriddenMethods[] from CXXMethodDecl.
1894   //
1895   //  Add an AbbrevOp for 'size then elements' and use it here.
1896   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1897   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1898   DeclCXXMethodAbbrev = Stream.EmitAbbrev(Abv);
1899 
1900   // Abbreviation for EXPR_DECL_REF
1901   Abv = new BitCodeAbbrev();
1902   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_DECL_REF));
1903   //Stmt
1904   //Expr
1905   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1906   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
1907   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
1908   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
1909   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
1910   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
1911   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
1912   //DeclRefExpr
1913   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HasQualifier
1914   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //GetDeclFound
1915   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ExplicitTemplateArgs
1916   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HadMultipleCandidates
1917   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1918                            1)); // RefersToEnclosingVariableOrCapture
1919   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclRef
1920   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
1921   DeclRefExprAbbrev = Stream.EmitAbbrev(Abv);
1922 
1923   // Abbreviation for EXPR_INTEGER_LITERAL
1924   Abv = new BitCodeAbbrev();
1925   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_INTEGER_LITERAL));
1926   //Stmt
1927   //Expr
1928   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1929   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
1930   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
1931   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
1932   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
1933   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
1934   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
1935   //Integer Literal
1936   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
1937   Abv->Add(BitCodeAbbrevOp(32));                      // Bit Width
1938   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Value
1939   IntegerLiteralAbbrev = Stream.EmitAbbrev(Abv);
1940 
1941   // Abbreviation for EXPR_CHARACTER_LITERAL
1942   Abv = new BitCodeAbbrev();
1943   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_CHARACTER_LITERAL));
1944   //Stmt
1945   //Expr
1946   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1947   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
1948   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
1949   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
1950   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
1951   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
1952   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
1953   //Character Literal
1954   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getValue
1955   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
1956   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // getKind
1957   CharacterLiteralAbbrev = Stream.EmitAbbrev(Abv);
1958 
1959   // Abbreviation for EXPR_IMPLICIT_CAST
1960   Abv = new BitCodeAbbrev();
1961   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_IMPLICIT_CAST));
1962   // Stmt
1963   // Expr
1964   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1965   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
1966   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
1967   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
1968   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
1969   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
1970   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
1971   // CastExpr
1972   Abv->Add(BitCodeAbbrevOp(0)); // PathSize
1973   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 6)); // CastKind
1974   // ImplicitCastExpr
1975   ExprImplicitCastAbbrev = Stream.EmitAbbrev(Abv);
1976 
1977   Abv = new BitCodeAbbrev();
1978   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_LEXICAL));
1979   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1980   DeclContextLexicalAbbrev = Stream.EmitAbbrev(Abv);
1981 
1982   Abv = new BitCodeAbbrev();
1983   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_VISIBLE));
1984   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1985   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1986   DeclContextVisibleLookupAbbrev = Stream.EmitAbbrev(Abv);
1987 }
1988 
1989 /// isRequiredDecl - Check if this is a "required" Decl, which must be seen by
1990 /// consumers of the AST.
1991 ///
1992 /// Such decls will always be deserialized from the AST file, so we would like
1993 /// this to be as restrictive as possible. Currently the predicate is driven by
1994 /// code generation requirements, if other clients have a different notion of
1995 /// what is "required" then we may have to consider an alternate scheme where
1996 /// clients can iterate over the top-level decls and get information on them,
1997 /// without necessary deserializing them. We could explicitly require such
1998 /// clients to use a separate API call to "realize" the decl. This should be
1999 /// relatively painless since they would presumably only do it for top-level
2000 /// decls.
2001 static bool isRequiredDecl(const Decl *D, ASTContext &Context) {
2002   // An ObjCMethodDecl is never considered as "required" because its
2003   // implementation container always is.
2004 
2005   // File scoped assembly or obj-c implementation must be seen. ImportDecl is
2006   // used by codegen to determine the set of imported modules to search for
2007   // inputs for automatic linking.
2008   if (isa<FileScopeAsmDecl>(D) || isa<ObjCImplDecl>(D) || isa<ImportDecl>(D))
2009     return true;
2010 
2011   return Context.DeclMustBeEmitted(D);
2012 }
2013 
2014 void ASTWriter::WriteDecl(ASTContext &Context, Decl *D) {
2015   // Switch case IDs are per Decl.
2016   ClearSwitchCaseIDs();
2017 
2018   RecordData Record;
2019   ASTDeclWriter W(*this, Context, Record);
2020 
2021   // Determine the ID for this declaration.
2022   serialization::DeclID ID;
2023   if (D->isFromASTFile()) {
2024     assert(isRewritten(D) && "should not be emitting imported decl");
2025     ID = getDeclID(D);
2026   } else {
2027     serialization::DeclID &IDR = DeclIDs[D];
2028     if (IDR == 0)
2029       IDR = NextDeclID++;
2030 
2031     ID= IDR;
2032   }
2033 
2034   bool isReplacingADecl = ID < FirstDeclID;
2035 
2036   // If this declaration is also a DeclContext, write blocks for the
2037   // declarations that lexically stored inside its context and those
2038   // declarations that are visible from its context. These blocks
2039   // are written before the declaration itself so that we can put
2040   // their offsets into the record for the declaration.
2041   uint64_t LexicalOffset = 0;
2042   uint64_t VisibleOffset = 0;
2043   DeclContext *DC = dyn_cast<DeclContext>(D);
2044   if (DC) {
2045     if (isReplacingADecl) {
2046       // It is replacing a decl from a chained PCH; make sure that the
2047       // DeclContext is fully loaded.
2048       if (DC->hasExternalLexicalStorage())
2049         DC->LoadLexicalDeclsFromExternalStorage();
2050       if (DC->hasExternalVisibleStorage())
2051         Chain->completeVisibleDeclsMap(DC);
2052     }
2053     LexicalOffset = WriteDeclContextLexicalBlock(Context, DC);
2054     VisibleOffset = WriteDeclContextVisibleBlock(Context, DC);
2055   }
2056 
2057   if (isReplacingADecl) {
2058     // We're replacing a decl in a previous file.
2059     ReplacedDecls.push_back(ReplacedDeclInfo(ID, Stream.GetCurrentBitNo(),
2060                                              D->getLocation()));
2061   } else {
2062     unsigned Index = ID - FirstDeclID;
2063 
2064     // Record the offset for this declaration
2065     SourceLocation Loc = D->getLocation();
2066     if (DeclOffsets.size() == Index)
2067       DeclOffsets.push_back(DeclOffset(Loc, Stream.GetCurrentBitNo()));
2068     else if (DeclOffsets.size() < Index) {
2069       DeclOffsets.resize(Index+1);
2070       DeclOffsets[Index].setLocation(Loc);
2071       DeclOffsets[Index].BitOffset = Stream.GetCurrentBitNo();
2072     }
2073 
2074     SourceManager &SM = Context.getSourceManager();
2075     if (Loc.isValid() && SM.isLocalSourceLocation(Loc))
2076       associateDeclWithFile(D, ID);
2077   }
2078 
2079   // Build and emit a record for this declaration
2080   Record.clear();
2081   W.Code = (serialization::DeclCode)0;
2082   W.AbbrevToUse = 0;
2083   W.Visit(D);
2084   if (DC) W.VisitDeclContext(DC, LexicalOffset, VisibleOffset);
2085 
2086   if (!W.Code)
2087     llvm::report_fatal_error(StringRef("unexpected declaration kind '") +
2088                             D->getDeclKindName() + "'");
2089   Stream.EmitRecord(W.Code, Record, W.AbbrevToUse);
2090 
2091   // Flush any expressions, base specifiers, and ctor initializers that
2092   // were written as part of this declaration.
2093   FlushPendingAfterDecl();
2094 
2095   // Note declarations that should be deserialized eagerly so that we can add
2096   // them to a record in the AST file later.
2097   if (isRequiredDecl(D, Context))
2098     EagerlyDeserializedDecls.push_back(ID);
2099 }
2100 
2101 void ASTWriter::AddFunctionDefinition(const FunctionDecl *FD,
2102                                       RecordData &Record) {
2103   ClearSwitchCaseIDs();
2104 
2105   ASTDeclWriter W(*this, FD->getASTContext(), Record);
2106   W.AddFunctionDefinition(FD);
2107 }
2108