1 //===--- ASTWriterDecl.cpp - Declaration Serialization --------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //  This file implements serialization for Declarations.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Serialization/ASTWriter.h"
15 #include "ASTCommon.h"
16 #include "clang/AST/DeclCXX.h"
17 #include "clang/AST/DeclContextInternals.h"
18 #include "clang/AST/DeclTemplate.h"
19 #include "clang/AST/DeclVisitor.h"
20 #include "clang/AST/Expr.h"
21 #include "clang/Basic/SourceManager.h"
22 #include "clang/Serialization/ASTReader.h"
23 #include "llvm/ADT/Twine.h"
24 #include "llvm/Bitcode/BitstreamWriter.h"
25 #include "llvm/Support/ErrorHandling.h"
26 using namespace clang;
27 using namespace serialization;
28 
29 //===----------------------------------------------------------------------===//
30 // Declaration serialization
31 //===----------------------------------------------------------------------===//
32 
33 namespace clang {
34   class ASTDeclWriter : public DeclVisitor<ASTDeclWriter, void> {
35 
36     ASTWriter &Writer;
37     ASTContext &Context;
38     typedef ASTWriter::RecordData RecordData;
39     RecordData &Record;
40 
41   public:
42     serialization::DeclCode Code;
43     unsigned AbbrevToUse;
44 
45     ASTDeclWriter(ASTWriter &Writer, ASTContext &Context, RecordData &Record)
46       : Writer(Writer), Context(Context), Record(Record) {
47     }
48 
49     void Visit(Decl *D);
50 
51     void VisitDecl(Decl *D);
52     void VisitTranslationUnitDecl(TranslationUnitDecl *D);
53     void VisitNamedDecl(NamedDecl *D);
54     void VisitLabelDecl(LabelDecl *LD);
55     void VisitNamespaceDecl(NamespaceDecl *D);
56     void VisitUsingDirectiveDecl(UsingDirectiveDecl *D);
57     void VisitNamespaceAliasDecl(NamespaceAliasDecl *D);
58     void VisitTypeDecl(TypeDecl *D);
59     void VisitTypedefNameDecl(TypedefNameDecl *D);
60     void VisitTypedefDecl(TypedefDecl *D);
61     void VisitTypeAliasDecl(TypeAliasDecl *D);
62     void VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D);
63     void VisitTagDecl(TagDecl *D);
64     void VisitEnumDecl(EnumDecl *D);
65     void VisitRecordDecl(RecordDecl *D);
66     void VisitCXXRecordDecl(CXXRecordDecl *D);
67     void VisitClassTemplateSpecializationDecl(
68                                             ClassTemplateSpecializationDecl *D);
69     void VisitClassTemplatePartialSpecializationDecl(
70                                      ClassTemplatePartialSpecializationDecl *D);
71     void VisitVarTemplateSpecializationDecl(VarTemplateSpecializationDecl *D);
72     void VisitVarTemplatePartialSpecializationDecl(
73         VarTemplatePartialSpecializationDecl *D);
74     void VisitClassScopeFunctionSpecializationDecl(
75                                        ClassScopeFunctionSpecializationDecl *D);
76     void VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
77     void VisitValueDecl(ValueDecl *D);
78     void VisitEnumConstantDecl(EnumConstantDecl *D);
79     void VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D);
80     void VisitDeclaratorDecl(DeclaratorDecl *D);
81     void VisitFunctionDecl(FunctionDecl *D);
82     void VisitCXXMethodDecl(CXXMethodDecl *D);
83     void VisitCXXConstructorDecl(CXXConstructorDecl *D);
84     void VisitCXXDestructorDecl(CXXDestructorDecl *D);
85     void VisitCXXConversionDecl(CXXConversionDecl *D);
86     void VisitFieldDecl(FieldDecl *D);
87     void VisitMSPropertyDecl(MSPropertyDecl *D);
88     void VisitIndirectFieldDecl(IndirectFieldDecl *D);
89     void VisitVarDecl(VarDecl *D);
90     void VisitImplicitParamDecl(ImplicitParamDecl *D);
91     void VisitParmVarDecl(ParmVarDecl *D);
92     void VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
93     void VisitTemplateDecl(TemplateDecl *D);
94     void VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D);
95     void VisitClassTemplateDecl(ClassTemplateDecl *D);
96     void VisitVarTemplateDecl(VarTemplateDecl *D);
97     void VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
98     void VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
99     void VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D);
100     void VisitUsingDecl(UsingDecl *D);
101     void VisitUsingShadowDecl(UsingShadowDecl *D);
102     void VisitLinkageSpecDecl(LinkageSpecDecl *D);
103     void VisitFileScopeAsmDecl(FileScopeAsmDecl *D);
104     void VisitImportDecl(ImportDecl *D);
105     void VisitAccessSpecDecl(AccessSpecDecl *D);
106     void VisitFriendDecl(FriendDecl *D);
107     void VisitFriendTemplateDecl(FriendTemplateDecl *D);
108     void VisitStaticAssertDecl(StaticAssertDecl *D);
109     void VisitBlockDecl(BlockDecl *D);
110     void VisitCapturedDecl(CapturedDecl *D);
111     void VisitEmptyDecl(EmptyDecl *D);
112 
113     void VisitDeclContext(DeclContext *DC, uint64_t LexicalOffset,
114                           uint64_t VisibleOffset);
115     template <typename T> void VisitRedeclarable(Redeclarable<T> *D);
116 
117 
118     // FIXME: Put in the same order is DeclNodes.td?
119     void VisitObjCMethodDecl(ObjCMethodDecl *D);
120     void VisitObjCTypeParamDecl(ObjCTypeParamDecl *D);
121     void VisitObjCContainerDecl(ObjCContainerDecl *D);
122     void VisitObjCInterfaceDecl(ObjCInterfaceDecl *D);
123     void VisitObjCIvarDecl(ObjCIvarDecl *D);
124     void VisitObjCProtocolDecl(ObjCProtocolDecl *D);
125     void VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D);
126     void VisitObjCCategoryDecl(ObjCCategoryDecl *D);
127     void VisitObjCImplDecl(ObjCImplDecl *D);
128     void VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D);
129     void VisitObjCImplementationDecl(ObjCImplementationDecl *D);
130     void VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D);
131     void VisitObjCPropertyDecl(ObjCPropertyDecl *D);
132     void VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D);
133     void VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D);
134 
135     /// Add an Objective-C type parameter list to the given record.
136     void AddObjCTypeParamList(ObjCTypeParamList *typeParams) {
137       // Empty type parameter list.
138       if (!typeParams) {
139         Record.push_back(0);
140         return;
141       }
142 
143       Record.push_back(typeParams->size());
144       for (auto typeParam : *typeParams) {
145         Writer.AddDeclRef(typeParam, Record);
146       }
147       Writer.AddSourceLocation(typeParams->getLAngleLoc(), Record);
148       Writer.AddSourceLocation(typeParams->getRAngleLoc(), Record);
149     }
150 
151     void AddFunctionDefinition(const FunctionDecl *FD) {
152       assert(FD->doesThisDeclarationHaveABody());
153       if (auto *CD = dyn_cast<CXXConstructorDecl>(FD)) {
154         Record.push_back(CD->NumCtorInitializers);
155         if (CD->NumCtorInitializers)
156           Writer.AddCXXCtorInitializersRef(
157               llvm::makeArrayRef(CD->init_begin(), CD->init_end()), Record);
158       }
159       Writer.AddStmt(FD->getBody());
160     }
161 
162     /// Add to the record the first declaration from each module file that
163     /// provides a declaration of D. The intent is to provide a sufficient
164     /// set such that reloading this set will load all current redeclarations.
165     void AddFirstDeclFromEachModule(const Decl *D, bool IncludeLocal) {
166       llvm::MapVector<ModuleFile*, const Decl*> Firsts;
167       // FIXME: We can skip entries that we know are implied by others.
168       for (const Decl *R = D->getMostRecentDecl(); R; R = R->getPreviousDecl()) {
169         if (R->isFromASTFile())
170           Firsts[Writer.Chain->getOwningModuleFile(R)] = R;
171         else if (IncludeLocal)
172           Firsts[nullptr] = R;
173       }
174       for (const auto &F : Firsts)
175         Writer.AddDeclRef(F.second, Record);
176     }
177 
178     /// Get the specialization decl from an entry in the specialization list.
179     template <typename EntryType>
180     typename RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::DeclType *
181     getSpecializationDecl(EntryType &T) {
182       return RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::getDecl(&T);
183     }
184 
185     /// Get the list of partial specializations from a template's common ptr.
186     template<typename T>
187     decltype(T::PartialSpecializations) &getPartialSpecializations(T *Common) {
188       return Common->PartialSpecializations;
189     }
190     ArrayRef<Decl> getPartialSpecializations(FunctionTemplateDecl::Common *) {
191       return None;
192     }
193 
194     template<typename Decl>
195     void AddTemplateSpecializations(Decl *D) {
196       auto *Common = D->getCommonPtr();
197 
198       // If we have any lazy specializations, and the external AST source is
199       // our chained AST reader, we can just write out the DeclIDs. Otherwise,
200       // we need to resolve them to actual declarations.
201       if (Writer.Chain != Writer.Context->getExternalSource() &&
202           Common->LazySpecializations) {
203         D->LoadLazySpecializations();
204         assert(!Common->LazySpecializations);
205       }
206 
207       auto &Specializations = Common->Specializations;
208       auto &&PartialSpecializations = getPartialSpecializations(Common);
209       ArrayRef<DeclID> LazySpecializations;
210       if (auto *LS = Common->LazySpecializations)
211         LazySpecializations = llvm::makeArrayRef(LS + 1, LS[0]);
212 
213       // Add a slot to the record for the number of specializations.
214       unsigned I = Record.size();
215       Record.push_back(0);
216 
217       for (auto &Entry : Specializations) {
218         auto *D = getSpecializationDecl(Entry);
219         assert(D->isCanonicalDecl() && "non-canonical decl in set");
220         AddFirstDeclFromEachModule(D, /*IncludeLocal*/true);
221       }
222       for (auto &Entry : PartialSpecializations) {
223         auto *D = getSpecializationDecl(Entry);
224         assert(D->isCanonicalDecl() && "non-canonical decl in set");
225         AddFirstDeclFromEachModule(D, /*IncludeLocal*/true);
226       }
227       Record.append(LazySpecializations.begin(), LazySpecializations.end());
228 
229       // Update the size entry we added earlier.
230       Record[I] = Record.size() - I - 1;
231     }
232 
233     /// Ensure that this template specialization is associated with the specified
234     /// template on reload.
235     void RegisterTemplateSpecialization(const Decl *Template,
236                                         const Decl *Specialization) {
237       Template = Template->getCanonicalDecl();
238 
239       // If the canonical template is local, we'll write out this specialization
240       // when we emit it.
241       // FIXME: We can do the same thing if there is any local declaration of
242       // the template, to avoid emitting an update record.
243       if (!Template->isFromASTFile())
244         return;
245 
246       // We only need to associate the first local declaration of the
247       // specialization. The other declarations will get pulled in by it.
248       if (Writer.getFirstLocalDecl(Specialization) != Specialization)
249         return;
250 
251       Writer.DeclUpdates[Template].push_back(ASTWriter::DeclUpdate(
252           UPD_CXX_ADDED_TEMPLATE_SPECIALIZATION, Specialization));
253     }
254   };
255 }
256 
257 void ASTDeclWriter::Visit(Decl *D) {
258   DeclVisitor<ASTDeclWriter>::Visit(D);
259 
260   // Source locations require array (variable-length) abbreviations.  The
261   // abbreviation infrastructure requires that arrays are encoded last, so
262   // we handle it here in the case of those classes derived from DeclaratorDecl
263   if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D)){
264     Writer.AddTypeSourceInfo(DD->getTypeSourceInfo(), Record);
265   }
266 
267   // Handle FunctionDecl's body here and write it after all other Stmts/Exprs
268   // have been written. We want it last because we will not read it back when
269   // retrieving it from the AST, we'll just lazily set the offset.
270   if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
271     Record.push_back(FD->doesThisDeclarationHaveABody());
272     if (FD->doesThisDeclarationHaveABody())
273       AddFunctionDefinition(FD);
274   }
275 }
276 
277 void ASTDeclWriter::VisitDecl(Decl *D) {
278   Writer.AddDeclRef(cast_or_null<Decl>(D->getDeclContext()), Record);
279   Writer.AddDeclRef(cast_or_null<Decl>(D->getLexicalDeclContext()), Record);
280   Record.push_back(D->isInvalidDecl());
281   Record.push_back(D->hasAttrs());
282   if (D->hasAttrs())
283     Writer.WriteAttributes(llvm::makeArrayRef(D->getAttrs().begin(),
284                                               D->getAttrs().size()), Record);
285   Record.push_back(D->isImplicit());
286   Record.push_back(D->isUsed(false));
287   Record.push_back(D->isReferenced());
288   Record.push_back(D->isTopLevelDeclInObjCContainer());
289   Record.push_back(D->getAccess());
290   Record.push_back(D->isModulePrivate());
291   Record.push_back(Writer.inferSubmoduleIDFromLocation(D->getLocation()));
292 
293   // If this declaration injected a name into a context different from its
294   // lexical context, and that context is an imported namespace, we need to
295   // update its visible declarations to include this name.
296   //
297   // This happens when we instantiate a class with a friend declaration or a
298   // function with a local extern declaration, for instance.
299   //
300   // FIXME: Can we handle this in AddedVisibleDecl instead?
301   if (D->isOutOfLine()) {
302     auto *DC = D->getDeclContext();
303     while (auto *NS = dyn_cast<NamespaceDecl>(DC->getRedeclContext())) {
304       if (!NS->isFromASTFile())
305         break;
306       Writer.UpdatedDeclContexts.insert(NS->getPrimaryContext());
307       if (!NS->isInlineNamespace())
308         break;
309       DC = NS->getParent();
310     }
311   }
312 }
313 
314 void ASTDeclWriter::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
315   llvm_unreachable("Translation units aren't directly serialized");
316 }
317 
318 void ASTDeclWriter::VisitNamedDecl(NamedDecl *D) {
319   VisitDecl(D);
320   Writer.AddDeclarationName(D->getDeclName(), Record);
321   Record.push_back(needsAnonymousDeclarationNumber(D)
322                        ? Writer.getAnonymousDeclarationNumber(D)
323                        : 0);
324 }
325 
326 void ASTDeclWriter::VisitTypeDecl(TypeDecl *D) {
327   VisitNamedDecl(D);
328   Writer.AddSourceLocation(D->getLocStart(), Record);
329   Writer.AddTypeRef(QualType(D->getTypeForDecl(), 0), Record);
330 }
331 
332 void ASTDeclWriter::VisitTypedefNameDecl(TypedefNameDecl *D) {
333   VisitRedeclarable(D);
334   VisitTypeDecl(D);
335   Writer.AddTypeSourceInfo(D->getTypeSourceInfo(), Record);
336   Record.push_back(D->isModed());
337   if (D->isModed())
338     Writer.AddTypeRef(D->getUnderlyingType(), Record);
339 }
340 
341 void ASTDeclWriter::VisitTypedefDecl(TypedefDecl *D) {
342   VisitTypedefNameDecl(D);
343   if (!D->hasAttrs() &&
344       !D->isImplicit() &&
345       D->getFirstDecl() == D->getMostRecentDecl() &&
346       !D->isInvalidDecl() &&
347       !D->isTopLevelDeclInObjCContainer() &&
348       !D->isModulePrivate() &&
349       !needsAnonymousDeclarationNumber(D) &&
350       D->getDeclName().getNameKind() == DeclarationName::Identifier)
351     AbbrevToUse = Writer.getDeclTypedefAbbrev();
352 
353   Code = serialization::DECL_TYPEDEF;
354 }
355 
356 void ASTDeclWriter::VisitTypeAliasDecl(TypeAliasDecl *D) {
357   VisitTypedefNameDecl(D);
358   Writer.AddDeclRef(D->getDescribedAliasTemplate(), Record);
359   Code = serialization::DECL_TYPEALIAS;
360 }
361 
362 void ASTDeclWriter::VisitTagDecl(TagDecl *D) {
363   VisitRedeclarable(D);
364   VisitTypeDecl(D);
365   Record.push_back(D->getIdentifierNamespace());
366   Record.push_back((unsigned)D->getTagKind()); // FIXME: stable encoding
367   if (!isa<CXXRecordDecl>(D))
368     Record.push_back(D->isCompleteDefinition());
369   Record.push_back(D->isEmbeddedInDeclarator());
370   Record.push_back(D->isFreeStanding());
371   Record.push_back(D->isCompleteDefinitionRequired());
372   Writer.AddSourceLocation(D->getRBraceLoc(), Record);
373 
374   if (D->hasExtInfo()) {
375     Record.push_back(1);
376     Writer.AddQualifierInfo(*D->getExtInfo(), Record);
377   } else if (auto *TD = D->getTypedefNameForAnonDecl()) {
378     Record.push_back(2);
379     Writer.AddDeclRef(TD, Record);
380     Writer.AddIdentifierRef(TD->getDeclName().getAsIdentifierInfo(), Record);
381   } else {
382     Record.push_back(0);
383   }
384 }
385 
386 void ASTDeclWriter::VisitEnumDecl(EnumDecl *D) {
387   VisitTagDecl(D);
388   Writer.AddTypeSourceInfo(D->getIntegerTypeSourceInfo(), Record);
389   if (!D->getIntegerTypeSourceInfo())
390     Writer.AddTypeRef(D->getIntegerType(), Record);
391   Writer.AddTypeRef(D->getPromotionType(), Record);
392   Record.push_back(D->getNumPositiveBits());
393   Record.push_back(D->getNumNegativeBits());
394   Record.push_back(D->isScoped());
395   Record.push_back(D->isScopedUsingClassTag());
396   Record.push_back(D->isFixed());
397   if (MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo()) {
398     Writer.AddDeclRef(MemberInfo->getInstantiatedFrom(), Record);
399     Record.push_back(MemberInfo->getTemplateSpecializationKind());
400     Writer.AddSourceLocation(MemberInfo->getPointOfInstantiation(), Record);
401   } else {
402     Writer.AddDeclRef(nullptr, Record);
403   }
404 
405   if (!D->hasAttrs() &&
406       !D->isImplicit() &&
407       !D->isUsed(false) &&
408       !D->hasExtInfo() &&
409       !D->getTypedefNameForAnonDecl() &&
410       D->getFirstDecl() == D->getMostRecentDecl() &&
411       !D->isInvalidDecl() &&
412       !D->isReferenced() &&
413       !D->isTopLevelDeclInObjCContainer() &&
414       D->getAccess() == AS_none &&
415       !D->isModulePrivate() &&
416       !CXXRecordDecl::classofKind(D->getKind()) &&
417       !D->getIntegerTypeSourceInfo() &&
418       !D->getMemberSpecializationInfo() &&
419       !needsAnonymousDeclarationNumber(D) &&
420       D->getDeclName().getNameKind() == DeclarationName::Identifier)
421     AbbrevToUse = Writer.getDeclEnumAbbrev();
422 
423   Code = serialization::DECL_ENUM;
424 }
425 
426 void ASTDeclWriter::VisitRecordDecl(RecordDecl *D) {
427   VisitTagDecl(D);
428   Record.push_back(D->hasFlexibleArrayMember());
429   Record.push_back(D->isAnonymousStructOrUnion());
430   Record.push_back(D->hasObjectMember());
431   Record.push_back(D->hasVolatileMember());
432 
433   if (!D->hasAttrs() &&
434       !D->isImplicit() &&
435       !D->isUsed(false) &&
436       !D->hasExtInfo() &&
437       !D->getTypedefNameForAnonDecl() &&
438       D->getFirstDecl() == D->getMostRecentDecl() &&
439       !D->isInvalidDecl() &&
440       !D->isReferenced() &&
441       !D->isTopLevelDeclInObjCContainer() &&
442       D->getAccess() == AS_none &&
443       !D->isModulePrivate() &&
444       !CXXRecordDecl::classofKind(D->getKind()) &&
445       !needsAnonymousDeclarationNumber(D) &&
446       D->getDeclName().getNameKind() == DeclarationName::Identifier)
447     AbbrevToUse = Writer.getDeclRecordAbbrev();
448 
449   Code = serialization::DECL_RECORD;
450 }
451 
452 void ASTDeclWriter::VisitValueDecl(ValueDecl *D) {
453   VisitNamedDecl(D);
454   Writer.AddTypeRef(D->getType(), Record);
455 }
456 
457 void ASTDeclWriter::VisitEnumConstantDecl(EnumConstantDecl *D) {
458   VisitValueDecl(D);
459   Record.push_back(D->getInitExpr()? 1 : 0);
460   if (D->getInitExpr())
461     Writer.AddStmt(D->getInitExpr());
462   Writer.AddAPSInt(D->getInitVal(), Record);
463 
464   Code = serialization::DECL_ENUM_CONSTANT;
465 }
466 
467 void ASTDeclWriter::VisitDeclaratorDecl(DeclaratorDecl *D) {
468   VisitValueDecl(D);
469   Writer.AddSourceLocation(D->getInnerLocStart(), Record);
470   Record.push_back(D->hasExtInfo());
471   if (D->hasExtInfo())
472     Writer.AddQualifierInfo(*D->getExtInfo(), Record);
473 }
474 
475 void ASTDeclWriter::VisitFunctionDecl(FunctionDecl *D) {
476   VisitRedeclarable(D);
477   VisitDeclaratorDecl(D);
478   Writer.AddDeclarationNameLoc(D->DNLoc, D->getDeclName(), Record);
479   Record.push_back(D->getIdentifierNamespace());
480 
481   // FunctionDecl's body is handled last at ASTWriterDecl::Visit,
482   // after everything else is written.
483 
484   Record.push_back((int)D->SClass); // FIXME: stable encoding
485   Record.push_back(D->IsInline);
486   Record.push_back(D->IsInlineSpecified);
487   Record.push_back(D->IsVirtualAsWritten);
488   Record.push_back(D->IsPure);
489   Record.push_back(D->HasInheritedPrototype);
490   Record.push_back(D->HasWrittenPrototype);
491   Record.push_back(D->IsDeleted);
492   Record.push_back(D->IsTrivial);
493   Record.push_back(D->IsDefaulted);
494   Record.push_back(D->IsExplicitlyDefaulted);
495   Record.push_back(D->HasImplicitReturnZero);
496   Record.push_back(D->IsConstexpr);
497   Record.push_back(D->HasSkippedBody);
498   Record.push_back(D->IsLateTemplateParsed);
499   Record.push_back(D->getLinkageInternal());
500   Writer.AddSourceLocation(D->getLocEnd(), Record);
501 
502   Record.push_back(D->getTemplatedKind());
503   switch (D->getTemplatedKind()) {
504   case FunctionDecl::TK_NonTemplate:
505     break;
506   case FunctionDecl::TK_FunctionTemplate:
507     Writer.AddDeclRef(D->getDescribedFunctionTemplate(), Record);
508     break;
509   case FunctionDecl::TK_MemberSpecialization: {
510     MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo();
511     Writer.AddDeclRef(MemberInfo->getInstantiatedFrom(), Record);
512     Record.push_back(MemberInfo->getTemplateSpecializationKind());
513     Writer.AddSourceLocation(MemberInfo->getPointOfInstantiation(), Record);
514     break;
515   }
516   case FunctionDecl::TK_FunctionTemplateSpecialization: {
517     FunctionTemplateSpecializationInfo *
518       FTSInfo = D->getTemplateSpecializationInfo();
519 
520     RegisterTemplateSpecialization(FTSInfo->getTemplate(), D);
521 
522     Writer.AddDeclRef(FTSInfo->getTemplate(), Record);
523     Record.push_back(FTSInfo->getTemplateSpecializationKind());
524 
525     // Template arguments.
526     Writer.AddTemplateArgumentList(FTSInfo->TemplateArguments, Record);
527 
528     // Template args as written.
529     Record.push_back(FTSInfo->TemplateArgumentsAsWritten != nullptr);
530     if (FTSInfo->TemplateArgumentsAsWritten) {
531       Record.push_back(FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs);
532       for (int i=0, e = FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs;
533              i!=e; ++i)
534         Writer.AddTemplateArgumentLoc((*FTSInfo->TemplateArgumentsAsWritten)[i],
535                                       Record);
536       Writer.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->LAngleLoc,
537                                Record);
538       Writer.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->RAngleLoc,
539                                Record);
540     }
541 
542     Writer.AddSourceLocation(FTSInfo->getPointOfInstantiation(), Record);
543 
544     if (D->isCanonicalDecl()) {
545       // Write the template that contains the specializations set. We will
546       // add a FunctionTemplateSpecializationInfo to it when reading.
547       Writer.AddDeclRef(FTSInfo->getTemplate()->getCanonicalDecl(), Record);
548     }
549     break;
550   }
551   case FunctionDecl::TK_DependentFunctionTemplateSpecialization: {
552     DependentFunctionTemplateSpecializationInfo *
553       DFTSInfo = D->getDependentSpecializationInfo();
554 
555     // Templates.
556     Record.push_back(DFTSInfo->getNumTemplates());
557     for (int i=0, e = DFTSInfo->getNumTemplates(); i != e; ++i)
558       Writer.AddDeclRef(DFTSInfo->getTemplate(i), Record);
559 
560     // Templates args.
561     Record.push_back(DFTSInfo->getNumTemplateArgs());
562     for (int i=0, e = DFTSInfo->getNumTemplateArgs(); i != e; ++i)
563       Writer.AddTemplateArgumentLoc(DFTSInfo->getTemplateArg(i), Record);
564     Writer.AddSourceLocation(DFTSInfo->getLAngleLoc(), Record);
565     Writer.AddSourceLocation(DFTSInfo->getRAngleLoc(), Record);
566     break;
567   }
568   }
569 
570   Record.push_back(D->param_size());
571   for (auto P : D->params())
572     Writer.AddDeclRef(P, Record);
573   Code = serialization::DECL_FUNCTION;
574 }
575 
576 void ASTDeclWriter::VisitObjCMethodDecl(ObjCMethodDecl *D) {
577   VisitNamedDecl(D);
578   // FIXME: convert to LazyStmtPtr?
579   // Unlike C/C++, method bodies will never be in header files.
580   bool HasBodyStuff = D->getBody() != nullptr     ||
581                       D->getSelfDecl() != nullptr || D->getCmdDecl() != nullptr;
582   Record.push_back(HasBodyStuff);
583   if (HasBodyStuff) {
584     Writer.AddStmt(D->getBody());
585     Writer.AddDeclRef(D->getSelfDecl(), Record);
586     Writer.AddDeclRef(D->getCmdDecl(), Record);
587   }
588   Record.push_back(D->isInstanceMethod());
589   Record.push_back(D->isVariadic());
590   Record.push_back(D->isPropertyAccessor());
591   Record.push_back(D->isDefined());
592   Record.push_back(D->IsOverriding);
593   Record.push_back(D->HasSkippedBody);
594 
595   Record.push_back(D->IsRedeclaration);
596   Record.push_back(D->HasRedeclaration);
597   if (D->HasRedeclaration) {
598     assert(Context.getObjCMethodRedeclaration(D));
599     Writer.AddDeclRef(Context.getObjCMethodRedeclaration(D), Record);
600   }
601 
602   // FIXME: stable encoding for @required/@optional
603   Record.push_back(D->getImplementationControl());
604   // FIXME: stable encoding for in/out/inout/bycopy/byref/oneway/nullability
605   Record.push_back(D->getObjCDeclQualifier());
606   Record.push_back(D->hasRelatedResultType());
607   Writer.AddTypeRef(D->getReturnType(), Record);
608   Writer.AddTypeSourceInfo(D->getReturnTypeSourceInfo(), Record);
609   Writer.AddSourceLocation(D->getLocEnd(), Record);
610   Record.push_back(D->param_size());
611   for (const auto *P : D->params())
612     Writer.AddDeclRef(P, Record);
613 
614   Record.push_back(D->SelLocsKind);
615   unsigned NumStoredSelLocs = D->getNumStoredSelLocs();
616   SourceLocation *SelLocs = D->getStoredSelLocs();
617   Record.push_back(NumStoredSelLocs);
618   for (unsigned i = 0; i != NumStoredSelLocs; ++i)
619     Writer.AddSourceLocation(SelLocs[i], Record);
620 
621   Code = serialization::DECL_OBJC_METHOD;
622 }
623 
624 void ASTDeclWriter::VisitObjCTypeParamDecl(ObjCTypeParamDecl *D) {
625   VisitTypedefNameDecl(D);
626   Record.push_back(D->Variance);
627   Record.push_back(D->Index);
628   Writer.AddSourceLocation(D->VarianceLoc, Record);
629   Writer.AddSourceLocation(D->ColonLoc, Record);
630 
631   Code = serialization::DECL_OBJC_TYPE_PARAM;
632 }
633 
634 void ASTDeclWriter::VisitObjCContainerDecl(ObjCContainerDecl *D) {
635   VisitNamedDecl(D);
636   Writer.AddSourceLocation(D->getAtStartLoc(), Record);
637   Writer.AddSourceRange(D->getAtEndRange(), Record);
638   // Abstract class (no need to define a stable serialization::DECL code).
639 }
640 
641 void ASTDeclWriter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
642   VisitRedeclarable(D);
643   VisitObjCContainerDecl(D);
644   Writer.AddTypeRef(QualType(D->getTypeForDecl(), 0), Record);
645   AddObjCTypeParamList(D->TypeParamList);
646 
647   Record.push_back(D->isThisDeclarationADefinition());
648   if (D->isThisDeclarationADefinition()) {
649     // Write the DefinitionData
650     ObjCInterfaceDecl::DefinitionData &Data = D->data();
651 
652     Writer.AddTypeSourceInfo(D->getSuperClassTInfo(), Record);
653     Writer.AddSourceLocation(D->getEndOfDefinitionLoc(), Record);
654     Record.push_back(Data.HasDesignatedInitializers);
655 
656     // Write out the protocols that are directly referenced by the @interface.
657     Record.push_back(Data.ReferencedProtocols.size());
658     for (const auto *P : D->protocols())
659       Writer.AddDeclRef(P, Record);
660     for (const auto &PL : D->protocol_locs())
661       Writer.AddSourceLocation(PL, Record);
662 
663     // Write out the protocols that are transitively referenced.
664     Record.push_back(Data.AllReferencedProtocols.size());
665     for (ObjCList<ObjCProtocolDecl>::iterator
666               P = Data.AllReferencedProtocols.begin(),
667            PEnd = Data.AllReferencedProtocols.end();
668          P != PEnd; ++P)
669       Writer.AddDeclRef(*P, Record);
670 
671 
672     if (ObjCCategoryDecl *Cat = D->getCategoryListRaw()) {
673       // Ensure that we write out the set of categories for this class.
674       Writer.ObjCClassesWithCategories.insert(D);
675 
676       // Make sure that the categories get serialized.
677       for (; Cat; Cat = Cat->getNextClassCategoryRaw())
678         (void)Writer.GetDeclRef(Cat);
679     }
680   }
681 
682   Code = serialization::DECL_OBJC_INTERFACE;
683 }
684 
685 void ASTDeclWriter::VisitObjCIvarDecl(ObjCIvarDecl *D) {
686   VisitFieldDecl(D);
687   // FIXME: stable encoding for @public/@private/@protected/@package
688   Record.push_back(D->getAccessControl());
689   Record.push_back(D->getSynthesize());
690 
691   if (!D->hasAttrs() &&
692       !D->isImplicit() &&
693       !D->isUsed(false) &&
694       !D->isInvalidDecl() &&
695       !D->isReferenced() &&
696       !D->isModulePrivate() &&
697       !D->getBitWidth() &&
698       !D->hasExtInfo() &&
699       D->getDeclName())
700     AbbrevToUse = Writer.getDeclObjCIvarAbbrev();
701 
702   Code = serialization::DECL_OBJC_IVAR;
703 }
704 
705 void ASTDeclWriter::VisitObjCProtocolDecl(ObjCProtocolDecl *D) {
706   VisitRedeclarable(D);
707   VisitObjCContainerDecl(D);
708 
709   Record.push_back(D->isThisDeclarationADefinition());
710   if (D->isThisDeclarationADefinition()) {
711     Record.push_back(D->protocol_size());
712     for (const auto *I : D->protocols())
713       Writer.AddDeclRef(I, Record);
714     for (const auto &PL : D->protocol_locs())
715       Writer.AddSourceLocation(PL, Record);
716   }
717 
718   Code = serialization::DECL_OBJC_PROTOCOL;
719 }
720 
721 void ASTDeclWriter::VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D) {
722   VisitFieldDecl(D);
723   Code = serialization::DECL_OBJC_AT_DEFS_FIELD;
724 }
725 
726 void ASTDeclWriter::VisitObjCCategoryDecl(ObjCCategoryDecl *D) {
727   VisitObjCContainerDecl(D);
728   Writer.AddSourceLocation(D->getCategoryNameLoc(), Record);
729   Writer.AddSourceLocation(D->getIvarLBraceLoc(), Record);
730   Writer.AddSourceLocation(D->getIvarRBraceLoc(), Record);
731   Writer.AddDeclRef(D->getClassInterface(), Record);
732   AddObjCTypeParamList(D->TypeParamList);
733   Record.push_back(D->protocol_size());
734   for (const auto *I : D->protocols())
735     Writer.AddDeclRef(I, Record);
736   for (const auto &PL : D->protocol_locs())
737     Writer.AddSourceLocation(PL, Record);
738   Code = serialization::DECL_OBJC_CATEGORY;
739 }
740 
741 void ASTDeclWriter::VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D) {
742   VisitNamedDecl(D);
743   Writer.AddDeclRef(D->getClassInterface(), Record);
744   Code = serialization::DECL_OBJC_COMPATIBLE_ALIAS;
745 }
746 
747 void ASTDeclWriter::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
748   VisitNamedDecl(D);
749   Writer.AddSourceLocation(D->getAtLoc(), Record);
750   Writer.AddSourceLocation(D->getLParenLoc(), Record);
751   Writer.AddTypeRef(D->getType(), Record);
752   Writer.AddTypeSourceInfo(D->getTypeSourceInfo(), Record);
753   // FIXME: stable encoding
754   Record.push_back((unsigned)D->getPropertyAttributes());
755   Record.push_back((unsigned)D->getPropertyAttributesAsWritten());
756   // FIXME: stable encoding
757   Record.push_back((unsigned)D->getPropertyImplementation());
758   Writer.AddDeclarationName(D->getGetterName(), Record);
759   Writer.AddDeclarationName(D->getSetterName(), Record);
760   Writer.AddDeclRef(D->getGetterMethodDecl(), Record);
761   Writer.AddDeclRef(D->getSetterMethodDecl(), Record);
762   Writer.AddDeclRef(D->getPropertyIvarDecl(), Record);
763   Code = serialization::DECL_OBJC_PROPERTY;
764 }
765 
766 void ASTDeclWriter::VisitObjCImplDecl(ObjCImplDecl *D) {
767   VisitObjCContainerDecl(D);
768   Writer.AddDeclRef(D->getClassInterface(), Record);
769   // Abstract class (no need to define a stable serialization::DECL code).
770 }
771 
772 void ASTDeclWriter::VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D) {
773   VisitObjCImplDecl(D);
774   Writer.AddIdentifierRef(D->getIdentifier(), Record);
775   Writer.AddSourceLocation(D->getCategoryNameLoc(), Record);
776   Code = serialization::DECL_OBJC_CATEGORY_IMPL;
777 }
778 
779 void ASTDeclWriter::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
780   VisitObjCImplDecl(D);
781   Writer.AddDeclRef(D->getSuperClass(), Record);
782   Writer.AddSourceLocation(D->getSuperClassLoc(), Record);
783   Writer.AddSourceLocation(D->getIvarLBraceLoc(), Record);
784   Writer.AddSourceLocation(D->getIvarRBraceLoc(), Record);
785   Record.push_back(D->hasNonZeroConstructors());
786   Record.push_back(D->hasDestructors());
787   Record.push_back(D->NumIvarInitializers);
788   if (D->NumIvarInitializers)
789     Writer.AddCXXCtorInitializersRef(
790         llvm::makeArrayRef(D->init_begin(), D->init_end()), Record);
791   Code = serialization::DECL_OBJC_IMPLEMENTATION;
792 }
793 
794 void ASTDeclWriter::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
795   VisitDecl(D);
796   Writer.AddSourceLocation(D->getLocStart(), Record);
797   Writer.AddDeclRef(D->getPropertyDecl(), Record);
798   Writer.AddDeclRef(D->getPropertyIvarDecl(), Record);
799   Writer.AddSourceLocation(D->getPropertyIvarDeclLoc(), Record);
800   Writer.AddStmt(D->getGetterCXXConstructor());
801   Writer.AddStmt(D->getSetterCXXAssignment());
802   Code = serialization::DECL_OBJC_PROPERTY_IMPL;
803 }
804 
805 void ASTDeclWriter::VisitFieldDecl(FieldDecl *D) {
806   VisitDeclaratorDecl(D);
807   Record.push_back(D->isMutable());
808   if (D->InitStorage.getInt() == FieldDecl::ISK_BitWidthOrNothing &&
809       D->InitStorage.getPointer() == nullptr) {
810     Record.push_back(0);
811   } else if (D->InitStorage.getInt() == FieldDecl::ISK_CapturedVLAType) {
812     Record.push_back(D->InitStorage.getInt() + 1);
813     Writer.AddTypeRef(
814         QualType(static_cast<Type *>(D->InitStorage.getPointer()), 0),
815         Record);
816   } else {
817     Record.push_back(D->InitStorage.getInt() + 1);
818     Writer.AddStmt(static_cast<Expr *>(D->InitStorage.getPointer()));
819   }
820   if (!D->getDeclName())
821     Writer.AddDeclRef(Context.getInstantiatedFromUnnamedFieldDecl(D), Record);
822 
823   if (!D->hasAttrs() &&
824       !D->isImplicit() &&
825       !D->isUsed(false) &&
826       !D->isInvalidDecl() &&
827       !D->isReferenced() &&
828       !D->isTopLevelDeclInObjCContainer() &&
829       !D->isModulePrivate() &&
830       !D->getBitWidth() &&
831       !D->hasInClassInitializer() &&
832       !D->hasExtInfo() &&
833       !ObjCIvarDecl::classofKind(D->getKind()) &&
834       !ObjCAtDefsFieldDecl::classofKind(D->getKind()) &&
835       D->getDeclName())
836     AbbrevToUse = Writer.getDeclFieldAbbrev();
837 
838   Code = serialization::DECL_FIELD;
839 }
840 
841 void ASTDeclWriter::VisitMSPropertyDecl(MSPropertyDecl *D) {
842   VisitDeclaratorDecl(D);
843   Writer.AddIdentifierRef(D->getGetterId(), Record);
844   Writer.AddIdentifierRef(D->getSetterId(), Record);
845   Code = serialization::DECL_MS_PROPERTY;
846 }
847 
848 void ASTDeclWriter::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
849   VisitValueDecl(D);
850   Record.push_back(D->getChainingSize());
851 
852   for (const auto *P : D->chain())
853     Writer.AddDeclRef(P, Record);
854   Code = serialization::DECL_INDIRECTFIELD;
855 }
856 
857 void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
858   VisitRedeclarable(D);
859   VisitDeclaratorDecl(D);
860   Record.push_back(D->getStorageClass());
861   Record.push_back(D->getTSCSpec());
862   Record.push_back(D->getInitStyle());
863   if (!isa<ParmVarDecl>(D)) {
864     Record.push_back(D->isExceptionVariable());
865     Record.push_back(D->isNRVOVariable());
866     Record.push_back(D->isCXXForRangeDecl());
867     Record.push_back(D->isARCPseudoStrong());
868     Record.push_back(D->isConstexpr());
869     Record.push_back(D->isInitCapture());
870     Record.push_back(D->isPreviousDeclInSameBlockScope());
871   }
872   Record.push_back(D->getLinkageInternal());
873 
874   if (D->getInit()) {
875     Record.push_back(!D->isInitKnownICE() ? 1 : (D->isInitICE() ? 3 : 2));
876     Writer.AddStmt(D->getInit());
877   } else {
878     Record.push_back(0);
879   }
880 
881   enum {
882     VarNotTemplate = 0, VarTemplate, StaticDataMemberSpecialization
883   };
884   if (VarTemplateDecl *TemplD = D->getDescribedVarTemplate()) {
885     Record.push_back(VarTemplate);
886     Writer.AddDeclRef(TemplD, Record);
887   } else if (MemberSpecializationInfo *SpecInfo
888                = D->getMemberSpecializationInfo()) {
889     Record.push_back(StaticDataMemberSpecialization);
890     Writer.AddDeclRef(SpecInfo->getInstantiatedFrom(), Record);
891     Record.push_back(SpecInfo->getTemplateSpecializationKind());
892     Writer.AddSourceLocation(SpecInfo->getPointOfInstantiation(), Record);
893   } else {
894     Record.push_back(VarNotTemplate);
895   }
896 
897   if (!D->hasAttrs() &&
898       !D->isImplicit() &&
899       !D->isUsed(false) &&
900       !D->isInvalidDecl() &&
901       !D->isReferenced() &&
902       !D->isTopLevelDeclInObjCContainer() &&
903       D->getAccess() == AS_none &&
904       !D->isModulePrivate() &&
905       !needsAnonymousDeclarationNumber(D) &&
906       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
907       !D->hasExtInfo() &&
908       D->getFirstDecl() == D->getMostRecentDecl() &&
909       D->getInitStyle() == VarDecl::CInit &&
910       D->getInit() == nullptr &&
911       !isa<ParmVarDecl>(D) &&
912       !isa<VarTemplateSpecializationDecl>(D) &&
913       !D->isConstexpr() &&
914       !D->isInitCapture() &&
915       !D->isPreviousDeclInSameBlockScope() &&
916       !D->getMemberSpecializationInfo())
917     AbbrevToUse = Writer.getDeclVarAbbrev();
918 
919   Code = serialization::DECL_VAR;
920 }
921 
922 void ASTDeclWriter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
923   VisitVarDecl(D);
924   Code = serialization::DECL_IMPLICIT_PARAM;
925 }
926 
927 void ASTDeclWriter::VisitParmVarDecl(ParmVarDecl *D) {
928   VisitVarDecl(D);
929   Record.push_back(D->isObjCMethodParameter());
930   Record.push_back(D->getFunctionScopeDepth());
931   Record.push_back(D->getFunctionScopeIndex());
932   Record.push_back(D->getObjCDeclQualifier()); // FIXME: stable encoding
933   Record.push_back(D->isKNRPromoted());
934   Record.push_back(D->hasInheritedDefaultArg());
935   Record.push_back(D->hasUninstantiatedDefaultArg());
936   if (D->hasUninstantiatedDefaultArg())
937     Writer.AddStmt(D->getUninstantiatedDefaultArg());
938   Code = serialization::DECL_PARM_VAR;
939 
940   assert(!D->isARCPseudoStrong()); // can be true of ImplicitParamDecl
941 
942   // If the assumptions about the DECL_PARM_VAR abbrev are true, use it.  Here
943   // we dynamically check for the properties that we optimize for, but don't
944   // know are true of all PARM_VAR_DECLs.
945   if (!D->hasAttrs() &&
946       !D->hasExtInfo() &&
947       !D->isImplicit() &&
948       !D->isUsed(false) &&
949       !D->isInvalidDecl() &&
950       !D->isReferenced() &&
951       D->getAccess() == AS_none &&
952       !D->isModulePrivate() &&
953       D->getStorageClass() == 0 &&
954       D->getInitStyle() == VarDecl::CInit && // Can params have anything else?
955       D->getFunctionScopeDepth() == 0 &&
956       D->getObjCDeclQualifier() == 0 &&
957       !D->isKNRPromoted() &&
958       !D->hasInheritedDefaultArg() &&
959       D->getInit() == nullptr &&
960       !D->hasUninstantiatedDefaultArg())  // No default expr.
961     AbbrevToUse = Writer.getDeclParmVarAbbrev();
962 
963   // Check things we know are true of *every* PARM_VAR_DECL, which is more than
964   // just us assuming it.
965   assert(!D->getTSCSpec() && "PARM_VAR_DECL can't use TLS");
966   assert(D->getAccess() == AS_none && "PARM_VAR_DECL can't be public/private");
967   assert(!D->isExceptionVariable() && "PARM_VAR_DECL can't be exception var");
968   assert(D->getPreviousDecl() == nullptr && "PARM_VAR_DECL can't be redecl");
969   assert(!D->isStaticDataMember() &&
970          "PARM_VAR_DECL can't be static data member");
971 }
972 
973 void ASTDeclWriter::VisitFileScopeAsmDecl(FileScopeAsmDecl *D) {
974   VisitDecl(D);
975   Writer.AddStmt(D->getAsmString());
976   Writer.AddSourceLocation(D->getRParenLoc(), Record);
977   Code = serialization::DECL_FILE_SCOPE_ASM;
978 }
979 
980 void ASTDeclWriter::VisitEmptyDecl(EmptyDecl *D) {
981   VisitDecl(D);
982   Code = serialization::DECL_EMPTY;
983 }
984 
985 void ASTDeclWriter::VisitBlockDecl(BlockDecl *D) {
986   VisitDecl(D);
987   Writer.AddStmt(D->getBody());
988   Writer.AddTypeSourceInfo(D->getSignatureAsWritten(), Record);
989   Record.push_back(D->param_size());
990   for (FunctionDecl::param_iterator P = D->param_begin(), PEnd = D->param_end();
991        P != PEnd; ++P)
992     Writer.AddDeclRef(*P, Record);
993   Record.push_back(D->isVariadic());
994   Record.push_back(D->blockMissingReturnType());
995   Record.push_back(D->isConversionFromLambda());
996   Record.push_back(D->capturesCXXThis());
997   Record.push_back(D->getNumCaptures());
998   for (const auto &capture : D->captures()) {
999     Writer.AddDeclRef(capture.getVariable(), Record);
1000 
1001     unsigned flags = 0;
1002     if (capture.isByRef()) flags |= 1;
1003     if (capture.isNested()) flags |= 2;
1004     if (capture.hasCopyExpr()) flags |= 4;
1005     Record.push_back(flags);
1006 
1007     if (capture.hasCopyExpr()) Writer.AddStmt(capture.getCopyExpr());
1008   }
1009 
1010   Code = serialization::DECL_BLOCK;
1011 }
1012 
1013 void ASTDeclWriter::VisitCapturedDecl(CapturedDecl *CD) {
1014   Record.push_back(CD->getNumParams());
1015   VisitDecl(CD);
1016   Record.push_back(CD->getContextParamPosition());
1017   Record.push_back(CD->isNothrow() ? 1 : 0);
1018   // Body is stored by VisitCapturedStmt.
1019   for (unsigned I = 0; I < CD->getNumParams(); ++I)
1020     Writer.AddDeclRef(CD->getParam(I), Record);
1021   Code = serialization::DECL_CAPTURED;
1022 }
1023 
1024 void ASTDeclWriter::VisitLinkageSpecDecl(LinkageSpecDecl *D) {
1025   VisitDecl(D);
1026   Record.push_back(D->getLanguage());
1027   Writer.AddSourceLocation(D->getExternLoc(), Record);
1028   Writer.AddSourceLocation(D->getRBraceLoc(), Record);
1029   Code = serialization::DECL_LINKAGE_SPEC;
1030 }
1031 
1032 void ASTDeclWriter::VisitLabelDecl(LabelDecl *D) {
1033   VisitNamedDecl(D);
1034   Writer.AddSourceLocation(D->getLocStart(), Record);
1035   Code = serialization::DECL_LABEL;
1036 }
1037 
1038 
1039 void ASTDeclWriter::VisitNamespaceDecl(NamespaceDecl *D) {
1040   VisitRedeclarable(D);
1041   VisitNamedDecl(D);
1042   Record.push_back(D->isInline());
1043   Writer.AddSourceLocation(D->getLocStart(), Record);
1044   Writer.AddSourceLocation(D->getRBraceLoc(), Record);
1045 
1046   if (D->isOriginalNamespace())
1047     Writer.AddDeclRef(D->getAnonymousNamespace(), Record);
1048   Code = serialization::DECL_NAMESPACE;
1049 
1050   if (Writer.hasChain() && D->isAnonymousNamespace() &&
1051       D == D->getMostRecentDecl()) {
1052     // This is a most recent reopening of the anonymous namespace. If its parent
1053     // is in a previous PCH (or is the TU), mark that parent for update, because
1054     // the original namespace always points to the latest re-opening of its
1055     // anonymous namespace.
1056     Decl *Parent = cast<Decl>(
1057         D->getParent()->getRedeclContext()->getPrimaryContext());
1058     if (Parent->isFromASTFile() || isa<TranslationUnitDecl>(Parent)) {
1059       Writer.DeclUpdates[Parent].push_back(
1060           ASTWriter::DeclUpdate(UPD_CXX_ADDED_ANONYMOUS_NAMESPACE, D));
1061     }
1062   }
1063 }
1064 
1065 void ASTDeclWriter::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
1066   VisitRedeclarable(D);
1067   VisitNamedDecl(D);
1068   Writer.AddSourceLocation(D->getNamespaceLoc(), Record);
1069   Writer.AddSourceLocation(D->getTargetNameLoc(), Record);
1070   Writer.AddNestedNameSpecifierLoc(D->getQualifierLoc(), Record);
1071   Writer.AddDeclRef(D->getNamespace(), Record);
1072   Code = serialization::DECL_NAMESPACE_ALIAS;
1073 }
1074 
1075 void ASTDeclWriter::VisitUsingDecl(UsingDecl *D) {
1076   VisitNamedDecl(D);
1077   Writer.AddSourceLocation(D->getUsingLoc(), Record);
1078   Writer.AddNestedNameSpecifierLoc(D->getQualifierLoc(), Record);
1079   Writer.AddDeclarationNameLoc(D->DNLoc, D->getDeclName(), Record);
1080   Writer.AddDeclRef(D->FirstUsingShadow.getPointer(), Record);
1081   Record.push_back(D->hasTypename());
1082   Writer.AddDeclRef(Context.getInstantiatedFromUsingDecl(D), Record);
1083   Code = serialization::DECL_USING;
1084 }
1085 
1086 void ASTDeclWriter::VisitUsingShadowDecl(UsingShadowDecl *D) {
1087   VisitRedeclarable(D);
1088   VisitNamedDecl(D);
1089   Writer.AddDeclRef(D->getTargetDecl(), Record);
1090   Writer.AddDeclRef(D->UsingOrNextShadow, Record);
1091   Writer.AddDeclRef(Context.getInstantiatedFromUsingShadowDecl(D), Record);
1092   Code = serialization::DECL_USING_SHADOW;
1093 }
1094 
1095 void ASTDeclWriter::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1096   VisitNamedDecl(D);
1097   Writer.AddSourceLocation(D->getUsingLoc(), Record);
1098   Writer.AddSourceLocation(D->getNamespaceKeyLocation(), Record);
1099   Writer.AddNestedNameSpecifierLoc(D->getQualifierLoc(), Record);
1100   Writer.AddDeclRef(D->getNominatedNamespace(), Record);
1101   Writer.AddDeclRef(dyn_cast<Decl>(D->getCommonAncestor()), Record);
1102   Code = serialization::DECL_USING_DIRECTIVE;
1103 }
1104 
1105 void ASTDeclWriter::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1106   VisitValueDecl(D);
1107   Writer.AddSourceLocation(D->getUsingLoc(), Record);
1108   Writer.AddNestedNameSpecifierLoc(D->getQualifierLoc(), Record);
1109   Writer.AddDeclarationNameLoc(D->DNLoc, D->getDeclName(), Record);
1110   Code = serialization::DECL_UNRESOLVED_USING_VALUE;
1111 }
1112 
1113 void ASTDeclWriter::VisitUnresolvedUsingTypenameDecl(
1114                                                UnresolvedUsingTypenameDecl *D) {
1115   VisitTypeDecl(D);
1116   Writer.AddSourceLocation(D->getTypenameLoc(), Record);
1117   Writer.AddNestedNameSpecifierLoc(D->getQualifierLoc(), Record);
1118   Code = serialization::DECL_UNRESOLVED_USING_TYPENAME;
1119 }
1120 
1121 void ASTDeclWriter::VisitCXXRecordDecl(CXXRecordDecl *D) {
1122   VisitRecordDecl(D);
1123 
1124   enum {
1125     CXXRecNotTemplate = 0, CXXRecTemplate, CXXRecMemberSpecialization
1126   };
1127   if (ClassTemplateDecl *TemplD = D->getDescribedClassTemplate()) {
1128     Record.push_back(CXXRecTemplate);
1129     Writer.AddDeclRef(TemplD, Record);
1130   } else if (MemberSpecializationInfo *MSInfo
1131                = D->getMemberSpecializationInfo()) {
1132     Record.push_back(CXXRecMemberSpecialization);
1133     Writer.AddDeclRef(MSInfo->getInstantiatedFrom(), Record);
1134     Record.push_back(MSInfo->getTemplateSpecializationKind());
1135     Writer.AddSourceLocation(MSInfo->getPointOfInstantiation(), Record);
1136   } else {
1137     Record.push_back(CXXRecNotTemplate);
1138   }
1139 
1140   Record.push_back(D->isThisDeclarationADefinition());
1141   if (D->isThisDeclarationADefinition())
1142     Writer.AddCXXDefinitionData(D, Record);
1143 
1144   // Store (what we currently believe to be) the key function to avoid
1145   // deserializing every method so we can compute it.
1146   if (D->IsCompleteDefinition)
1147     Writer.AddDeclRef(Context.getCurrentKeyFunction(D), Record);
1148 
1149   Code = serialization::DECL_CXX_RECORD;
1150 }
1151 
1152 void ASTDeclWriter::VisitCXXMethodDecl(CXXMethodDecl *D) {
1153   VisitFunctionDecl(D);
1154   if (D->isCanonicalDecl()) {
1155     Record.push_back(D->size_overridden_methods());
1156     for (CXXMethodDecl::method_iterator
1157            I = D->begin_overridden_methods(), E = D->end_overridden_methods();
1158            I != E; ++I)
1159       Writer.AddDeclRef(*I, Record);
1160   } else {
1161     // We only need to record overridden methods once for the canonical decl.
1162     Record.push_back(0);
1163   }
1164 
1165   if (D->getFirstDecl() == D->getMostRecentDecl() &&
1166       !D->isInvalidDecl() &&
1167       !D->hasAttrs() &&
1168       !D->isTopLevelDeclInObjCContainer() &&
1169       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1170       !D->hasExtInfo() &&
1171       !D->hasInheritedPrototype() &&
1172       D->hasWrittenPrototype())
1173     AbbrevToUse = Writer.getDeclCXXMethodAbbrev();
1174 
1175   Code = serialization::DECL_CXX_METHOD;
1176 }
1177 
1178 void ASTDeclWriter::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1179   VisitCXXMethodDecl(D);
1180 
1181   Writer.AddDeclRef(D->getInheritedConstructor(), Record);
1182   Record.push_back(D->IsExplicitSpecified);
1183 
1184   Code = serialization::DECL_CXX_CONSTRUCTOR;
1185 }
1186 
1187 void ASTDeclWriter::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1188   VisitCXXMethodDecl(D);
1189 
1190   Writer.AddDeclRef(D->getOperatorDelete(), Record);
1191 
1192   Code = serialization::DECL_CXX_DESTRUCTOR;
1193 }
1194 
1195 void ASTDeclWriter::VisitCXXConversionDecl(CXXConversionDecl *D) {
1196   VisitCXXMethodDecl(D);
1197   Record.push_back(D->IsExplicitSpecified);
1198   Code = serialization::DECL_CXX_CONVERSION;
1199 }
1200 
1201 void ASTDeclWriter::VisitImportDecl(ImportDecl *D) {
1202   VisitDecl(D);
1203   Record.push_back(Writer.getSubmoduleID(D->getImportedModule()));
1204   ArrayRef<SourceLocation> IdentifierLocs = D->getIdentifierLocs();
1205   Record.push_back(!IdentifierLocs.empty());
1206   if (IdentifierLocs.empty()) {
1207     Writer.AddSourceLocation(D->getLocEnd(), Record);
1208     Record.push_back(1);
1209   } else {
1210     for (unsigned I = 0, N = IdentifierLocs.size(); I != N; ++I)
1211       Writer.AddSourceLocation(IdentifierLocs[I], Record);
1212     Record.push_back(IdentifierLocs.size());
1213   }
1214   // Note: the number of source locations must always be the last element in
1215   // the record.
1216   Code = serialization::DECL_IMPORT;
1217 }
1218 
1219 void ASTDeclWriter::VisitAccessSpecDecl(AccessSpecDecl *D) {
1220   VisitDecl(D);
1221   Writer.AddSourceLocation(D->getColonLoc(), Record);
1222   Code = serialization::DECL_ACCESS_SPEC;
1223 }
1224 
1225 void ASTDeclWriter::VisitFriendDecl(FriendDecl *D) {
1226   // Record the number of friend type template parameter lists here
1227   // so as to simplify memory allocation during deserialization.
1228   Record.push_back(D->NumTPLists);
1229   VisitDecl(D);
1230   bool hasFriendDecl = D->Friend.is<NamedDecl*>();
1231   Record.push_back(hasFriendDecl);
1232   if (hasFriendDecl)
1233     Writer.AddDeclRef(D->getFriendDecl(), Record);
1234   else
1235     Writer.AddTypeSourceInfo(D->getFriendType(), Record);
1236   for (unsigned i = 0; i < D->NumTPLists; ++i)
1237     Writer.AddTemplateParameterList(D->getFriendTypeTemplateParameterList(i),
1238                                     Record);
1239   Writer.AddDeclRef(D->getNextFriend(), Record);
1240   Record.push_back(D->UnsupportedFriend);
1241   Writer.AddSourceLocation(D->FriendLoc, Record);
1242   Code = serialization::DECL_FRIEND;
1243 }
1244 
1245 void ASTDeclWriter::VisitFriendTemplateDecl(FriendTemplateDecl *D) {
1246   VisitDecl(D);
1247   Record.push_back(D->getNumTemplateParameters());
1248   for (unsigned i = 0, e = D->getNumTemplateParameters(); i != e; ++i)
1249     Writer.AddTemplateParameterList(D->getTemplateParameterList(i), Record);
1250   Record.push_back(D->getFriendDecl() != nullptr);
1251   if (D->getFriendDecl())
1252     Writer.AddDeclRef(D->getFriendDecl(), Record);
1253   else
1254     Writer.AddTypeSourceInfo(D->getFriendType(), Record);
1255   Writer.AddSourceLocation(D->getFriendLoc(), Record);
1256   Code = serialization::DECL_FRIEND_TEMPLATE;
1257 }
1258 
1259 void ASTDeclWriter::VisitTemplateDecl(TemplateDecl *D) {
1260   VisitNamedDecl(D);
1261 
1262   Writer.AddDeclRef(D->getTemplatedDecl(), Record);
1263   Writer.AddTemplateParameterList(D->getTemplateParameters(), Record);
1264 }
1265 
1266 void ASTDeclWriter::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
1267   VisitRedeclarable(D);
1268 
1269   // Emit data to initialize CommonOrPrev before VisitTemplateDecl so that
1270   // getCommonPtr() can be used while this is still initializing.
1271   if (D->isFirstDecl()) {
1272     // This declaration owns the 'common' pointer, so serialize that data now.
1273     Writer.AddDeclRef(D->getInstantiatedFromMemberTemplate(), Record);
1274     if (D->getInstantiatedFromMemberTemplate())
1275       Record.push_back(D->isMemberSpecialization());
1276   }
1277 
1278   VisitTemplateDecl(D);
1279   Record.push_back(D->getIdentifierNamespace());
1280 }
1281 
1282 void ASTDeclWriter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
1283   VisitRedeclarableTemplateDecl(D);
1284 
1285   if (D->isFirstDecl())
1286     AddTemplateSpecializations(D);
1287   Code = serialization::DECL_CLASS_TEMPLATE;
1288 }
1289 
1290 void ASTDeclWriter::VisitClassTemplateSpecializationDecl(
1291                                            ClassTemplateSpecializationDecl *D) {
1292   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1293 
1294   VisitCXXRecordDecl(D);
1295 
1296   llvm::PointerUnion<ClassTemplateDecl *,
1297                      ClassTemplatePartialSpecializationDecl *> InstFrom
1298     = D->getSpecializedTemplateOrPartial();
1299   if (Decl *InstFromD = InstFrom.dyn_cast<ClassTemplateDecl *>()) {
1300     Writer.AddDeclRef(InstFromD, Record);
1301   } else {
1302     Writer.AddDeclRef(InstFrom.get<ClassTemplatePartialSpecializationDecl *>(),
1303                       Record);
1304     Writer.AddTemplateArgumentList(&D->getTemplateInstantiationArgs(), Record);
1305   }
1306 
1307   Writer.AddTemplateArgumentList(&D->getTemplateArgs(), Record);
1308   Writer.AddSourceLocation(D->getPointOfInstantiation(), Record);
1309   Record.push_back(D->getSpecializationKind());
1310   Record.push_back(D->isCanonicalDecl());
1311 
1312   if (D->isCanonicalDecl()) {
1313     // When reading, we'll add it to the folding set of the following template.
1314     Writer.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl(), Record);
1315   }
1316 
1317   // Explicit info.
1318   Writer.AddTypeSourceInfo(D->getTypeAsWritten(), Record);
1319   if (D->getTypeAsWritten()) {
1320     Writer.AddSourceLocation(D->getExternLoc(), Record);
1321     Writer.AddSourceLocation(D->getTemplateKeywordLoc(), Record);
1322   }
1323 
1324   Code = serialization::DECL_CLASS_TEMPLATE_SPECIALIZATION;
1325 }
1326 
1327 void ASTDeclWriter::VisitClassTemplatePartialSpecializationDecl(
1328                                     ClassTemplatePartialSpecializationDecl *D) {
1329   VisitClassTemplateSpecializationDecl(D);
1330 
1331   Writer.AddTemplateParameterList(D->getTemplateParameters(), Record);
1332   Writer.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten(), Record);
1333 
1334   // These are read/set from/to the first declaration.
1335   if (D->getPreviousDecl() == nullptr) {
1336     Writer.AddDeclRef(D->getInstantiatedFromMember(), Record);
1337     Record.push_back(D->isMemberSpecialization());
1338   }
1339 
1340   Code = serialization::DECL_CLASS_TEMPLATE_PARTIAL_SPECIALIZATION;
1341 }
1342 
1343 void ASTDeclWriter::VisitVarTemplateDecl(VarTemplateDecl *D) {
1344   VisitRedeclarableTemplateDecl(D);
1345 
1346   if (D->isFirstDecl())
1347     AddTemplateSpecializations(D);
1348   Code = serialization::DECL_VAR_TEMPLATE;
1349 }
1350 
1351 void ASTDeclWriter::VisitVarTemplateSpecializationDecl(
1352     VarTemplateSpecializationDecl *D) {
1353   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1354 
1355   VisitVarDecl(D);
1356 
1357   llvm::PointerUnion<VarTemplateDecl *, VarTemplatePartialSpecializationDecl *>
1358   InstFrom = D->getSpecializedTemplateOrPartial();
1359   if (Decl *InstFromD = InstFrom.dyn_cast<VarTemplateDecl *>()) {
1360     Writer.AddDeclRef(InstFromD, Record);
1361   } else {
1362     Writer.AddDeclRef(InstFrom.get<VarTemplatePartialSpecializationDecl *>(),
1363                       Record);
1364     Writer.AddTemplateArgumentList(&D->getTemplateInstantiationArgs(), Record);
1365   }
1366 
1367   // Explicit info.
1368   Writer.AddTypeSourceInfo(D->getTypeAsWritten(), Record);
1369   if (D->getTypeAsWritten()) {
1370     Writer.AddSourceLocation(D->getExternLoc(), Record);
1371     Writer.AddSourceLocation(D->getTemplateKeywordLoc(), Record);
1372   }
1373 
1374   Writer.AddTemplateArgumentList(&D->getTemplateArgs(), Record);
1375   Writer.AddSourceLocation(D->getPointOfInstantiation(), Record);
1376   Record.push_back(D->getSpecializationKind());
1377   Record.push_back(D->isCanonicalDecl());
1378 
1379   if (D->isCanonicalDecl()) {
1380     // When reading, we'll add it to the folding set of the following template.
1381     Writer.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl(), Record);
1382   }
1383 
1384   Code = serialization::DECL_VAR_TEMPLATE_SPECIALIZATION;
1385 }
1386 
1387 void ASTDeclWriter::VisitVarTemplatePartialSpecializationDecl(
1388     VarTemplatePartialSpecializationDecl *D) {
1389   VisitVarTemplateSpecializationDecl(D);
1390 
1391   Writer.AddTemplateParameterList(D->getTemplateParameters(), Record);
1392   Writer.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten(), Record);
1393 
1394   // These are read/set from/to the first declaration.
1395   if (D->getPreviousDecl() == nullptr) {
1396     Writer.AddDeclRef(D->getInstantiatedFromMember(), Record);
1397     Record.push_back(D->isMemberSpecialization());
1398   }
1399 
1400   Code = serialization::DECL_VAR_TEMPLATE_PARTIAL_SPECIALIZATION;
1401 }
1402 
1403 void ASTDeclWriter::VisitClassScopeFunctionSpecializationDecl(
1404                                     ClassScopeFunctionSpecializationDecl *D) {
1405   VisitDecl(D);
1406   Writer.AddDeclRef(D->getSpecialization(), Record);
1407   Code = serialization::DECL_CLASS_SCOPE_FUNCTION_SPECIALIZATION;
1408 }
1409 
1410 
1411 void ASTDeclWriter::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
1412   VisitRedeclarableTemplateDecl(D);
1413 
1414   if (D->isFirstDecl())
1415     AddTemplateSpecializations(D);
1416   Code = serialization::DECL_FUNCTION_TEMPLATE;
1417 }
1418 
1419 void ASTDeclWriter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
1420   VisitTypeDecl(D);
1421 
1422   Record.push_back(D->wasDeclaredWithTypename());
1423 
1424   bool OwnsDefaultArg = D->hasDefaultArgument() &&
1425                         !D->defaultArgumentWasInherited();
1426   Record.push_back(OwnsDefaultArg);
1427   if (OwnsDefaultArg)
1428     Writer.AddTypeSourceInfo(D->getDefaultArgumentInfo(), Record);
1429 
1430   Code = serialization::DECL_TEMPLATE_TYPE_PARM;
1431 }
1432 
1433 void ASTDeclWriter::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
1434   // For an expanded parameter pack, record the number of expansion types here
1435   // so that it's easier for deserialization to allocate the right amount of
1436   // memory.
1437   if (D->isExpandedParameterPack())
1438     Record.push_back(D->getNumExpansionTypes());
1439 
1440   VisitDeclaratorDecl(D);
1441   // TemplateParmPosition.
1442   Record.push_back(D->getDepth());
1443   Record.push_back(D->getPosition());
1444 
1445   if (D->isExpandedParameterPack()) {
1446     for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1447       Writer.AddTypeRef(D->getExpansionType(I), Record);
1448       Writer.AddTypeSourceInfo(D->getExpansionTypeSourceInfo(I), Record);
1449     }
1450 
1451     Code = serialization::DECL_EXPANDED_NON_TYPE_TEMPLATE_PARM_PACK;
1452   } else {
1453     // Rest of NonTypeTemplateParmDecl.
1454     Record.push_back(D->isParameterPack());
1455     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1456                           !D->defaultArgumentWasInherited();
1457     Record.push_back(OwnsDefaultArg);
1458     if (OwnsDefaultArg)
1459       Writer.AddStmt(D->getDefaultArgument());
1460     Code = serialization::DECL_NON_TYPE_TEMPLATE_PARM;
1461   }
1462 }
1463 
1464 void ASTDeclWriter::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
1465   // For an expanded parameter pack, record the number of expansion types here
1466   // so that it's easier for deserialization to allocate the right amount of
1467   // memory.
1468   if (D->isExpandedParameterPack())
1469     Record.push_back(D->getNumExpansionTemplateParameters());
1470 
1471   VisitTemplateDecl(D);
1472   // TemplateParmPosition.
1473   Record.push_back(D->getDepth());
1474   Record.push_back(D->getPosition());
1475 
1476   if (D->isExpandedParameterPack()) {
1477     for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
1478          I != N; ++I)
1479       Writer.AddTemplateParameterList(D->getExpansionTemplateParameters(I),
1480                                       Record);
1481     Code = serialization::DECL_EXPANDED_TEMPLATE_TEMPLATE_PARM_PACK;
1482   } else {
1483     // Rest of TemplateTemplateParmDecl.
1484     Record.push_back(D->isParameterPack());
1485     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1486                           !D->defaultArgumentWasInherited();
1487     Record.push_back(OwnsDefaultArg);
1488     if (OwnsDefaultArg)
1489       Writer.AddTemplateArgumentLoc(D->getDefaultArgument(), Record);
1490     Code = serialization::DECL_TEMPLATE_TEMPLATE_PARM;
1491   }
1492 }
1493 
1494 void ASTDeclWriter::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
1495   VisitRedeclarableTemplateDecl(D);
1496   Code = serialization::DECL_TYPE_ALIAS_TEMPLATE;
1497 }
1498 
1499 void ASTDeclWriter::VisitStaticAssertDecl(StaticAssertDecl *D) {
1500   VisitDecl(D);
1501   Writer.AddStmt(D->getAssertExpr());
1502   Record.push_back(D->isFailed());
1503   Writer.AddStmt(D->getMessage());
1504   Writer.AddSourceLocation(D->getRParenLoc(), Record);
1505   Code = serialization::DECL_STATIC_ASSERT;
1506 }
1507 
1508 /// \brief Emit the DeclContext part of a declaration context decl.
1509 ///
1510 /// \param LexicalOffset the offset at which the DECL_CONTEXT_LEXICAL
1511 /// block for this declaration context is stored. May be 0 to indicate
1512 /// that there are no declarations stored within this context.
1513 ///
1514 /// \param VisibleOffset the offset at which the DECL_CONTEXT_VISIBLE
1515 /// block for this declaration context is stored. May be 0 to indicate
1516 /// that there are no declarations visible from this context. Note
1517 /// that this value will not be emitted for non-primary declaration
1518 /// contexts.
1519 void ASTDeclWriter::VisitDeclContext(DeclContext *DC, uint64_t LexicalOffset,
1520                                      uint64_t VisibleOffset) {
1521   Record.push_back(LexicalOffset);
1522   Record.push_back(VisibleOffset);
1523 }
1524 
1525 const Decl *ASTWriter::getFirstLocalDecl(const Decl *D) {
1526   /// \brief Is this a local declaration (that is, one that will be written to
1527   /// our AST file)? This is the case for declarations that are neither imported
1528   /// from another AST file nor predefined.
1529   auto IsLocalDecl = [&](const Decl *D) -> bool {
1530     if (D->isFromASTFile())
1531       return false;
1532     auto I = DeclIDs.find(D);
1533     return (I == DeclIDs.end() || I->second >= NUM_PREDEF_DECL_IDS);
1534   };
1535 
1536   assert(IsLocalDecl(D) && "expected a local declaration");
1537 
1538   const Decl *Canon = D->getCanonicalDecl();
1539   if (IsLocalDecl(Canon))
1540     return Canon;
1541 
1542   const Decl *&CacheEntry = FirstLocalDeclCache[Canon];
1543   if (CacheEntry)
1544     return CacheEntry;
1545 
1546   for (const Decl *Redecl = D; Redecl; Redecl = Redecl->getPreviousDecl())
1547     if (IsLocalDecl(Redecl))
1548       D = Redecl;
1549   return CacheEntry = D;
1550 }
1551 
1552 template <typename T>
1553 void ASTDeclWriter::VisitRedeclarable(Redeclarable<T> *D) {
1554   T *First = D->getFirstDecl();
1555   T *MostRecent = First->getMostRecentDecl();
1556   T *DAsT = static_cast<T *>(D);
1557   if (MostRecent != First) {
1558     assert(isRedeclarableDeclKind(DAsT->getKind()) &&
1559            "Not considered redeclarable?");
1560 
1561     Writer.AddDeclRef(First, Record);
1562 
1563     // Write out a list of local redeclarations of this declaration if it's the
1564     // first local declaration in the chain.
1565     const Decl *FirstLocal = Writer.getFirstLocalDecl(DAsT);
1566     if (DAsT == FirstLocal) {
1567       // Emit a list of all imported first declarations so that we can be sure
1568       // that all redeclarations visible to this module are before D in the
1569       // redecl chain.
1570       unsigned I = Record.size();
1571       Record.push_back(0);
1572       if (Writer.Chain)
1573         AddFirstDeclFromEachModule(DAsT, /*IncludeLocal*/false);
1574       // This is the number of imported first declarations + 1.
1575       Record[I] = Record.size() - I;
1576 
1577       // Collect the set of local redeclarations of this declaration, from
1578       // newest to oldest.
1579       RecordData LocalRedecls;
1580       for (const Decl *Prev = FirstLocal->getMostRecentDecl();
1581            Prev != FirstLocal; Prev = Prev->getPreviousDecl())
1582         if (!Prev->isFromASTFile())
1583           Writer.AddDeclRef(Prev, LocalRedecls);
1584 
1585       // If we have any redecls, write them now as a separate record preceding
1586       // the declaration itself.
1587       if (LocalRedecls.empty())
1588         Record.push_back(0);
1589       else {
1590         Record.push_back(Writer.Stream.GetCurrentBitNo());
1591         Writer.Stream.EmitRecord(LOCAL_REDECLARATIONS, LocalRedecls);
1592       }
1593     } else {
1594       Record.push_back(0);
1595       Writer.AddDeclRef(FirstLocal, Record);
1596     }
1597 
1598     // Make sure that we serialize both the previous and the most-recent
1599     // declarations, which (transitively) ensures that all declarations in the
1600     // chain get serialized.
1601     //
1602     // FIXME: This is not correct; when we reach an imported declaration we
1603     // won't emit its previous declaration.
1604     (void)Writer.GetDeclRef(D->getPreviousDecl());
1605     (void)Writer.GetDeclRef(MostRecent);
1606   } else {
1607     // We use the sentinel value 0 to indicate an only declaration.
1608     Record.push_back(0);
1609   }
1610 }
1611 
1612 void ASTDeclWriter::VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D) {
1613   Record.push_back(D->varlist_size());
1614   VisitDecl(D);
1615   for (auto *I : D->varlists())
1616     Writer.AddStmt(I);
1617   Code = serialization::DECL_OMP_THREADPRIVATE;
1618 }
1619 
1620 //===----------------------------------------------------------------------===//
1621 // ASTWriter Implementation
1622 //===----------------------------------------------------------------------===//
1623 
1624 void ASTWriter::WriteDeclAbbrevs() {
1625   using namespace llvm;
1626 
1627   BitCodeAbbrev *Abv;
1628 
1629   // Abbreviation for DECL_FIELD
1630   Abv = new BitCodeAbbrev();
1631   Abv->Add(BitCodeAbbrevOp(serialization::DECL_FIELD));
1632   // Decl
1633   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1634   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1635   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1636   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1637   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1638   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1639   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1640   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1641   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1642   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1643   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1644   // NamedDecl
1645   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1646   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1647   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1648   // ValueDecl
1649   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1650   // DeclaratorDecl
1651   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1652   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1653   // FieldDecl
1654   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1655   Abv->Add(BitCodeAbbrevOp(0));                       //getBitWidth
1656   // Type Source Info
1657   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1658   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1659   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1660   DeclFieldAbbrev = Stream.EmitAbbrev(Abv);
1661 
1662   // Abbreviation for DECL_OBJC_IVAR
1663   Abv = new BitCodeAbbrev();
1664   Abv->Add(BitCodeAbbrevOp(serialization::DECL_OBJC_IVAR));
1665   // Decl
1666   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1667   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1668   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1669   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1670   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1671   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1672   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1673   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1674   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1675   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1676   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1677   // NamedDecl
1678   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1679   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1680   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1681   // ValueDecl
1682   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1683   // DeclaratorDecl
1684   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1685   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1686   // FieldDecl
1687   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1688   Abv->Add(BitCodeAbbrevOp(0));                       //getBitWidth
1689   // ObjC Ivar
1690   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getAccessControl
1691   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getSynthesize
1692   // Type Source Info
1693   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1694   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1695   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1696   DeclObjCIvarAbbrev = Stream.EmitAbbrev(Abv);
1697 
1698   // Abbreviation for DECL_ENUM
1699   Abv = new BitCodeAbbrev();
1700   Abv->Add(BitCodeAbbrevOp(serialization::DECL_ENUM));
1701   // Redeclarable
1702   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1703   // Decl
1704   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1705   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1706   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1707   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1708   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1709   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1710   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1711   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1712   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1713   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1714   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1715   // NamedDecl
1716   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1717   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1718   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1719   // TypeDecl
1720   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1721   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1722   // TagDecl
1723   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
1724   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
1725   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
1726   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
1727   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
1728   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
1729   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1730   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
1731   // EnumDecl
1732   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddTypeRef
1733   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IntegerType
1734   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getPromotionType
1735   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumPositiveBits
1736   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumNegativeBits
1737   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScoped
1738   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScopedUsingClassTag
1739   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isFixed
1740   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InstantiatedMembEnum
1741   // DC
1742   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
1743   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
1744   DeclEnumAbbrev = Stream.EmitAbbrev(Abv);
1745 
1746   // Abbreviation for DECL_RECORD
1747   Abv = new BitCodeAbbrev();
1748   Abv->Add(BitCodeAbbrevOp(serialization::DECL_RECORD));
1749   // Redeclarable
1750   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1751   // Decl
1752   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1753   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1754   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1755   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1756   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1757   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1758   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1759   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1760   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1761   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1762   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1763   // NamedDecl
1764   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1765   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1766   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1767   // TypeDecl
1768   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1769   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1770   // TagDecl
1771   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
1772   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
1773   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
1774   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
1775   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
1776   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
1777   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1778   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
1779   // RecordDecl
1780   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // FlexibleArrayMember
1781   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // AnonymousStructUnion
1782   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasObjectMember
1783   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasVolatileMember
1784   // DC
1785   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
1786   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
1787   DeclRecordAbbrev = Stream.EmitAbbrev(Abv);
1788 
1789   // Abbreviation for DECL_PARM_VAR
1790   Abv = new BitCodeAbbrev();
1791   Abv->Add(BitCodeAbbrevOp(serialization::DECL_PARM_VAR));
1792   // Redeclarable
1793   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1794   // Decl
1795   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1796   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1797   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1798   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1799   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1800   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1801   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1802   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1803   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1804   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1805   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1806   // NamedDecl
1807   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1808   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1809   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1810   // ValueDecl
1811   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1812   // DeclaratorDecl
1813   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1814   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1815   // VarDecl
1816   Abv->Add(BitCodeAbbrevOp(0));                       // StorageClass
1817   Abv->Add(BitCodeAbbrevOp(0));                       // getTSCSpec
1818   Abv->Add(BitCodeAbbrevOp(0));                       // hasCXXDirectInitializer
1819   Abv->Add(BitCodeAbbrevOp(0));                       // Linkage
1820   Abv->Add(BitCodeAbbrevOp(0));                       // HasInit
1821   Abv->Add(BitCodeAbbrevOp(0));                   // HasMemberSpecializationInfo
1822   // ParmVarDecl
1823   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsObjCMethodParameter
1824   Abv->Add(BitCodeAbbrevOp(0));                       // ScopeDepth
1825   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ScopeIndex
1826   Abv->Add(BitCodeAbbrevOp(0));                       // ObjCDeclQualifier
1827   Abv->Add(BitCodeAbbrevOp(0));                       // KNRPromoted
1828   Abv->Add(BitCodeAbbrevOp(0));                       // HasInheritedDefaultArg
1829   Abv->Add(BitCodeAbbrevOp(0));                   // HasUninstantiatedDefaultArg
1830   // Type Source Info
1831   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1832   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1833   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1834   DeclParmVarAbbrev = Stream.EmitAbbrev(Abv);
1835 
1836   // Abbreviation for DECL_TYPEDEF
1837   Abv = new BitCodeAbbrev();
1838   Abv->Add(BitCodeAbbrevOp(serialization::DECL_TYPEDEF));
1839   // Redeclarable
1840   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1841   // Decl
1842   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1843   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1844   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1845   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1846   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1847   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isUsed
1848   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isReferenced
1849   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1850   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // C++ AccessSpecifier
1851   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1852   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1853   // NamedDecl
1854   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1855   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1856   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1857   // TypeDecl
1858   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1859   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1860   // TypedefDecl
1861   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1862   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1863   DeclTypedefAbbrev = Stream.EmitAbbrev(Abv);
1864 
1865   // Abbreviation for DECL_VAR
1866   Abv = new BitCodeAbbrev();
1867   Abv->Add(BitCodeAbbrevOp(serialization::DECL_VAR));
1868   // Redeclarable
1869   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1870   // Decl
1871   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1872   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LexicalDeclContext
1873   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1874   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1875   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1876   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1877   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1878   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1879   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1880   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1881   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1882   // NamedDecl
1883   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1884   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1885   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1886   // ValueDecl
1887   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1888   // DeclaratorDecl
1889   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1890   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1891   // VarDecl
1892   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // StorageClass
1893   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // getTSCSpec
1894   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // CXXDirectInitializer
1895   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isExceptionVariable
1896   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isNRVOVariable
1897   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCXXForRangeDecl
1898   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isARCPseudoStrong
1899   Abv->Add(BitCodeAbbrevOp(0));                         // isConstexpr
1900   Abv->Add(BitCodeAbbrevOp(0));                         // isInitCapture
1901   Abv->Add(BitCodeAbbrevOp(0));                         // isPrevDeclInSameScope
1902   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
1903   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // HasInit
1904   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // HasMemberSpecInfo
1905   // Type Source Info
1906   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1907   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1908   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1909   DeclVarAbbrev = Stream.EmitAbbrev(Abv);
1910 
1911   // Abbreviation for DECL_CXX_METHOD
1912   Abv = new BitCodeAbbrev();
1913   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CXX_METHOD));
1914   // RedeclarableDecl
1915   Abv->Add(BitCodeAbbrevOp(0));                         // CanonicalDecl
1916   // Decl
1917   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // DeclContext
1918   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalDeclContext
1919   Abv->Add(BitCodeAbbrevOp(0));                         // Invalid
1920   Abv->Add(BitCodeAbbrevOp(0));                         // HasAttrs
1921   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Implicit
1922   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Used
1923   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Referenced
1924   Abv->Add(BitCodeAbbrevOp(0));                         // InObjCContainer
1925   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // Access
1926   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ModulePrivate
1927   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SubmoduleID
1928   // NamedDecl
1929   Abv->Add(BitCodeAbbrevOp(DeclarationName::Identifier)); // NameKind
1930   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Identifier
1931   Abv->Add(BitCodeAbbrevOp(0));                         // AnonDeclNumber
1932   // ValueDecl
1933   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Type
1934   // DeclaratorDecl
1935   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InnerLocStart
1936   Abv->Add(BitCodeAbbrevOp(0));                         // HasExtInfo
1937   // FunctionDecl
1938   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 11)); // IDNS
1939   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // StorageClass
1940   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Inline
1941   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // InlineSpecified
1942   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // VirtualAsWritten
1943   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Pure
1944   Abv->Add(BitCodeAbbrevOp(0));                         // HasInheritedProto
1945   Abv->Add(BitCodeAbbrevOp(1));                         // HasWrittenProto
1946   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Deleted
1947   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Trivial
1948   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Defaulted
1949   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ExplicitlyDefaulted
1950   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ImplicitReturnZero
1951   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Constexpr
1952   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // SkippedBody
1953   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // LateParsed
1954   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
1955   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LocEnd
1956   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // TemplateKind
1957   // This Array slurps the rest of the record. Fortunately we want to encode
1958   // (nearly) all the remaining (variable number of) fields in the same way.
1959   //
1960   // This is the function template information if any, then
1961   //         NumParams and Params[] from FunctionDecl, and
1962   //         NumOverriddenMethods, OverriddenMethods[] from CXXMethodDecl.
1963   //
1964   //  Add an AbbrevOp for 'size then elements' and use it here.
1965   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1966   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1967   DeclCXXMethodAbbrev = Stream.EmitAbbrev(Abv);
1968 
1969   // Abbreviation for EXPR_DECL_REF
1970   Abv = new BitCodeAbbrev();
1971   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_DECL_REF));
1972   //Stmt
1973   //Expr
1974   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1975   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
1976   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
1977   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
1978   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
1979   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
1980   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
1981   //DeclRefExpr
1982   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HasQualifier
1983   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //GetDeclFound
1984   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ExplicitTemplateArgs
1985   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HadMultipleCandidates
1986   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1987                            1)); // RefersToEnclosingVariableOrCapture
1988   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclRef
1989   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
1990   DeclRefExprAbbrev = Stream.EmitAbbrev(Abv);
1991 
1992   // Abbreviation for EXPR_INTEGER_LITERAL
1993   Abv = new BitCodeAbbrev();
1994   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_INTEGER_LITERAL));
1995   //Stmt
1996   //Expr
1997   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1998   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
1999   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2000   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2001   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2002   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2003   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2004   //Integer Literal
2005   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2006   Abv->Add(BitCodeAbbrevOp(32));                      // Bit Width
2007   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Value
2008   IntegerLiteralAbbrev = Stream.EmitAbbrev(Abv);
2009 
2010   // Abbreviation for EXPR_CHARACTER_LITERAL
2011   Abv = new BitCodeAbbrev();
2012   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_CHARACTER_LITERAL));
2013   //Stmt
2014   //Expr
2015   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2016   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2017   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2018   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2019   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2020   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2021   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2022   //Character Literal
2023   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getValue
2024   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2025   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // getKind
2026   CharacterLiteralAbbrev = Stream.EmitAbbrev(Abv);
2027 
2028   // Abbreviation for EXPR_IMPLICIT_CAST
2029   Abv = new BitCodeAbbrev();
2030   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_IMPLICIT_CAST));
2031   // Stmt
2032   // Expr
2033   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2034   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2035   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2036   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2037   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2038   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2039   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2040   // CastExpr
2041   Abv->Add(BitCodeAbbrevOp(0)); // PathSize
2042   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 6)); // CastKind
2043   // ImplicitCastExpr
2044   ExprImplicitCastAbbrev = Stream.EmitAbbrev(Abv);
2045 
2046   Abv = new BitCodeAbbrev();
2047   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_LEXICAL));
2048   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2049   DeclContextLexicalAbbrev = Stream.EmitAbbrev(Abv);
2050 
2051   Abv = new BitCodeAbbrev();
2052   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_VISIBLE));
2053   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2054   DeclContextVisibleLookupAbbrev = Stream.EmitAbbrev(Abv);
2055 }
2056 
2057 /// isRequiredDecl - Check if this is a "required" Decl, which must be seen by
2058 /// consumers of the AST.
2059 ///
2060 /// Such decls will always be deserialized from the AST file, so we would like
2061 /// this to be as restrictive as possible. Currently the predicate is driven by
2062 /// code generation requirements, if other clients have a different notion of
2063 /// what is "required" then we may have to consider an alternate scheme where
2064 /// clients can iterate over the top-level decls and get information on them,
2065 /// without necessary deserializing them. We could explicitly require such
2066 /// clients to use a separate API call to "realize" the decl. This should be
2067 /// relatively painless since they would presumably only do it for top-level
2068 /// decls.
2069 static bool isRequiredDecl(const Decl *D, ASTContext &Context,
2070                            bool WritingModule) {
2071   // An ObjCMethodDecl is never considered as "required" because its
2072   // implementation container always is.
2073 
2074   // File scoped assembly or obj-c implementation must be seen.
2075   if (isa<FileScopeAsmDecl>(D) || isa<ObjCImplDecl>(D))
2076     return true;
2077 
2078   // ImportDecl is used by codegen to determine the set of imported modules to
2079   // search for inputs for automatic linking; include it if it has a semantic
2080   // effect.
2081   if (isa<ImportDecl>(D) && !WritingModule)
2082     return true;
2083 
2084   return Context.DeclMustBeEmitted(D);
2085 }
2086 
2087 void ASTWriter::WriteDecl(ASTContext &Context, Decl *D) {
2088   // Switch case IDs are per Decl.
2089   ClearSwitchCaseIDs();
2090 
2091   RecordData Record;
2092   ASTDeclWriter W(*this, Context, Record);
2093 
2094   // Determine the ID for this declaration.
2095   serialization::DeclID ID;
2096   if (D->isFromASTFile()) {
2097     assert(isRewritten(D) && "should not be emitting imported decl");
2098     ID = getDeclID(D);
2099   } else {
2100     serialization::DeclID &IDR = DeclIDs[D];
2101     if (IDR == 0)
2102       IDR = NextDeclID++;
2103 
2104     ID= IDR;
2105   }
2106 
2107   bool isReplacingADecl = ID < FirstDeclID;
2108 
2109   // If this declaration is also a DeclContext, write blocks for the
2110   // declarations that lexically stored inside its context and those
2111   // declarations that are visible from its context. These blocks
2112   // are written before the declaration itself so that we can put
2113   // their offsets into the record for the declaration.
2114   uint64_t LexicalOffset = 0;
2115   uint64_t VisibleOffset = 0;
2116   DeclContext *DC = dyn_cast<DeclContext>(D);
2117   if (DC) {
2118     if (isReplacingADecl) {
2119       // It is replacing a decl from a chained PCH; make sure that the
2120       // DeclContext is fully loaded.
2121       if (DC->hasExternalLexicalStorage())
2122         DC->LoadLexicalDeclsFromExternalStorage();
2123       if (DC->hasExternalVisibleStorage())
2124         Chain->completeVisibleDeclsMap(DC);
2125     }
2126     LexicalOffset = WriteDeclContextLexicalBlock(Context, DC);
2127     VisibleOffset = WriteDeclContextVisibleBlock(Context, DC);
2128   }
2129 
2130   // Build a record for this declaration
2131   Record.clear();
2132   W.Code = (serialization::DeclCode)0;
2133   W.AbbrevToUse = 0;
2134   W.Visit(D);
2135   if (DC) W.VisitDeclContext(DC, LexicalOffset, VisibleOffset);
2136 
2137   if (isReplacingADecl) {
2138     // We're replacing a decl in a previous file.
2139     ReplacedDecls.push_back(ReplacedDeclInfo(ID, Stream.GetCurrentBitNo(),
2140                                              D->getLocation()));
2141   } else {
2142     unsigned Index = ID - FirstDeclID;
2143 
2144     // Record the offset for this declaration
2145     SourceLocation Loc = D->getLocation();
2146     if (DeclOffsets.size() == Index)
2147       DeclOffsets.push_back(DeclOffset(Loc, Stream.GetCurrentBitNo()));
2148     else if (DeclOffsets.size() < Index) {
2149       DeclOffsets.resize(Index+1);
2150       DeclOffsets[Index].setLocation(Loc);
2151       DeclOffsets[Index].BitOffset = Stream.GetCurrentBitNo();
2152     }
2153 
2154     SourceManager &SM = Context.getSourceManager();
2155     if (Loc.isValid() && SM.isLocalSourceLocation(Loc))
2156       associateDeclWithFile(D, ID);
2157   }
2158 
2159   if (!W.Code)
2160     llvm::report_fatal_error(StringRef("unexpected declaration kind '") +
2161                             D->getDeclKindName() + "'");
2162   Stream.EmitRecord(W.Code, Record, W.AbbrevToUse);
2163 
2164   // Flush any expressions, base specifiers, and ctor initializers that
2165   // were written as part of this declaration.
2166   FlushPendingAfterDecl();
2167 
2168   // Note declarations that should be deserialized eagerly so that we can add
2169   // them to a record in the AST file later.
2170   if (isRequiredDecl(D, Context, WritingModule))
2171     EagerlyDeserializedDecls.push_back(ID);
2172 }
2173 
2174 void ASTWriter::AddFunctionDefinition(const FunctionDecl *FD,
2175                                       RecordData &Record) {
2176   ClearSwitchCaseIDs();
2177 
2178   ASTDeclWriter W(*this, FD->getASTContext(), Record);
2179   W.AddFunctionDefinition(FD);
2180 }
2181