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