1 //===--- ASTWriterDecl.cpp - Declaration Serialization --------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 //  This file implements serialization for Declarations.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "ASTCommon.h"
14 #include "clang/AST/Attr.h"
15 #include "clang/AST/DeclCXX.h"
16 #include "clang/AST/DeclTemplate.h"
17 #include "clang/AST/DeclVisitor.h"
18 #include "clang/AST/Expr.h"
19 #include "clang/AST/OpenMPClause.h"
20 #include "clang/AST/PrettyDeclStackTrace.h"
21 #include "clang/Basic/SourceManager.h"
22 #include "clang/Serialization/ASTReader.h"
23 #include "clang/Serialization/ASTRecordWriter.h"
24 #include "llvm/Bitstream/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     ASTWriter &Writer;
36     ASTContext &Context;
37     ASTRecordWriter Record;
38 
39     serialization::DeclCode Code;
40     unsigned AbbrevToUse;
41 
42   public:
43     ASTDeclWriter(ASTWriter &Writer, ASTContext &Context,
44                   ASTWriter::RecordDataImpl &Record)
45         : Writer(Writer), Context(Context), Record(Writer, Record),
46           Code((serialization::DeclCode)0), AbbrevToUse(0) {}
47 
48     uint64_t Emit(Decl *D) {
49       if (!Code)
50         llvm::report_fatal_error(StringRef("unexpected declaration kind '") +
51             D->getDeclKindName() + "'");
52       return Record.Emit(Code, AbbrevToUse);
53     }
54 
55     void Visit(Decl *D);
56 
57     void VisitDecl(Decl *D);
58     void VisitPragmaCommentDecl(PragmaCommentDecl *D);
59     void VisitPragmaDetectMismatchDecl(PragmaDetectMismatchDecl *D);
60     void VisitTranslationUnitDecl(TranslationUnitDecl *D);
61     void VisitNamedDecl(NamedDecl *D);
62     void VisitLabelDecl(LabelDecl *LD);
63     void VisitNamespaceDecl(NamespaceDecl *D);
64     void VisitUsingDirectiveDecl(UsingDirectiveDecl *D);
65     void VisitNamespaceAliasDecl(NamespaceAliasDecl *D);
66     void VisitTypeDecl(TypeDecl *D);
67     void VisitTypedefNameDecl(TypedefNameDecl *D);
68     void VisitTypedefDecl(TypedefDecl *D);
69     void VisitTypeAliasDecl(TypeAliasDecl *D);
70     void VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D);
71     void VisitUnresolvedUsingIfExistsDecl(UnresolvedUsingIfExistsDecl *D);
72     void VisitTagDecl(TagDecl *D);
73     void VisitEnumDecl(EnumDecl *D);
74     void VisitRecordDecl(RecordDecl *D);
75     void VisitCXXRecordDecl(CXXRecordDecl *D);
76     void VisitClassTemplateSpecializationDecl(
77                                             ClassTemplateSpecializationDecl *D);
78     void VisitClassTemplatePartialSpecializationDecl(
79                                      ClassTemplatePartialSpecializationDecl *D);
80     void VisitVarTemplateSpecializationDecl(VarTemplateSpecializationDecl *D);
81     void VisitVarTemplatePartialSpecializationDecl(
82         VarTemplatePartialSpecializationDecl *D);
83     void VisitClassScopeFunctionSpecializationDecl(
84                                        ClassScopeFunctionSpecializationDecl *D);
85     void VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
86     void VisitValueDecl(ValueDecl *D);
87     void VisitEnumConstantDecl(EnumConstantDecl *D);
88     void VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D);
89     void VisitDeclaratorDecl(DeclaratorDecl *D);
90     void VisitFunctionDecl(FunctionDecl *D);
91     void VisitCXXDeductionGuideDecl(CXXDeductionGuideDecl *D);
92     void VisitCXXMethodDecl(CXXMethodDecl *D);
93     void VisitCXXConstructorDecl(CXXConstructorDecl *D);
94     void VisitCXXDestructorDecl(CXXDestructorDecl *D);
95     void VisitCXXConversionDecl(CXXConversionDecl *D);
96     void VisitFieldDecl(FieldDecl *D);
97     void VisitMSPropertyDecl(MSPropertyDecl *D);
98     void VisitMSGuidDecl(MSGuidDecl *D);
99     void VisitTemplateParamObjectDecl(TemplateParamObjectDecl *D);
100     void VisitIndirectFieldDecl(IndirectFieldDecl *D);
101     void VisitVarDecl(VarDecl *D);
102     void VisitImplicitParamDecl(ImplicitParamDecl *D);
103     void VisitParmVarDecl(ParmVarDecl *D);
104     void VisitDecompositionDecl(DecompositionDecl *D);
105     void VisitBindingDecl(BindingDecl *D);
106     void VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
107     void VisitTemplateDecl(TemplateDecl *D);
108     void VisitConceptDecl(ConceptDecl *D);
109     void VisitRequiresExprBodyDecl(RequiresExprBodyDecl *D);
110     void VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D);
111     void VisitClassTemplateDecl(ClassTemplateDecl *D);
112     void VisitVarTemplateDecl(VarTemplateDecl *D);
113     void VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
114     void VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
115     void VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D);
116     void VisitUsingDecl(UsingDecl *D);
117     void VisitUsingPackDecl(UsingPackDecl *D);
118     void VisitUsingShadowDecl(UsingShadowDecl *D);
119     void VisitConstructorUsingShadowDecl(ConstructorUsingShadowDecl *D);
120     void VisitLinkageSpecDecl(LinkageSpecDecl *D);
121     void VisitExportDecl(ExportDecl *D);
122     void VisitFileScopeAsmDecl(FileScopeAsmDecl *D);
123     void VisitImportDecl(ImportDecl *D);
124     void VisitAccessSpecDecl(AccessSpecDecl *D);
125     void VisitFriendDecl(FriendDecl *D);
126     void VisitFriendTemplateDecl(FriendTemplateDecl *D);
127     void VisitStaticAssertDecl(StaticAssertDecl *D);
128     void VisitBlockDecl(BlockDecl *D);
129     void VisitCapturedDecl(CapturedDecl *D);
130     void VisitEmptyDecl(EmptyDecl *D);
131     void VisitLifetimeExtendedTemporaryDecl(LifetimeExtendedTemporaryDecl *D);
132 
133     void VisitDeclContext(DeclContext *DC);
134     template <typename T> void VisitRedeclarable(Redeclarable<T> *D);
135 
136 
137     // FIXME: Put in the same order is DeclNodes.td?
138     void VisitObjCMethodDecl(ObjCMethodDecl *D);
139     void VisitObjCTypeParamDecl(ObjCTypeParamDecl *D);
140     void VisitObjCContainerDecl(ObjCContainerDecl *D);
141     void VisitObjCInterfaceDecl(ObjCInterfaceDecl *D);
142     void VisitObjCIvarDecl(ObjCIvarDecl *D);
143     void VisitObjCProtocolDecl(ObjCProtocolDecl *D);
144     void VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D);
145     void VisitObjCCategoryDecl(ObjCCategoryDecl *D);
146     void VisitObjCImplDecl(ObjCImplDecl *D);
147     void VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D);
148     void VisitObjCImplementationDecl(ObjCImplementationDecl *D);
149     void VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D);
150     void VisitObjCPropertyDecl(ObjCPropertyDecl *D);
151     void VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D);
152     void VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D);
153     void VisitOMPAllocateDecl(OMPAllocateDecl *D);
154     void VisitOMPRequiresDecl(OMPRequiresDecl *D);
155     void VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D);
156     void VisitOMPDeclareMapperDecl(OMPDeclareMapperDecl *D);
157     void VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D);
158 
159     /// Add an Objective-C type parameter list to the given record.
160     void AddObjCTypeParamList(ObjCTypeParamList *typeParams) {
161       // Empty type parameter list.
162       if (!typeParams) {
163         Record.push_back(0);
164         return;
165       }
166 
167       Record.push_back(typeParams->size());
168       for (auto typeParam : *typeParams) {
169         Record.AddDeclRef(typeParam);
170       }
171       Record.AddSourceLocation(typeParams->getLAngleLoc());
172       Record.AddSourceLocation(typeParams->getRAngleLoc());
173     }
174 
175     /// Add to the record the first declaration from each module file that
176     /// provides a declaration of D. The intent is to provide a sufficient
177     /// set such that reloading this set will load all current redeclarations.
178     void AddFirstDeclFromEachModule(const Decl *D, bool IncludeLocal) {
179       llvm::MapVector<ModuleFile*, const Decl*> Firsts;
180       // FIXME: We can skip entries that we know are implied by others.
181       for (const Decl *R = D->getMostRecentDecl(); R; R = R->getPreviousDecl()) {
182         if (R->isFromASTFile())
183           Firsts[Writer.Chain->getOwningModuleFile(R)] = R;
184         else if (IncludeLocal)
185           Firsts[nullptr] = R;
186       }
187       for (const auto &F : Firsts)
188         Record.AddDeclRef(F.second);
189     }
190 
191     /// Get the specialization decl from an entry in the specialization list.
192     template <typename EntryType>
193     typename RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::DeclType *
194     getSpecializationDecl(EntryType &T) {
195       return RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::getDecl(&T);
196     }
197 
198     /// Get the list of partial specializations from a template's common ptr.
199     template<typename T>
200     decltype(T::PartialSpecializations) &getPartialSpecializations(T *Common) {
201       return Common->PartialSpecializations;
202     }
203     ArrayRef<Decl> getPartialSpecializations(FunctionTemplateDecl::Common *) {
204       return None;
205     }
206 
207     template<typename DeclTy>
208     void AddTemplateSpecializations(DeclTy *D) {
209       auto *Common = D->getCommonPtr();
210 
211       // If we have any lazy specializations, and the external AST source is
212       // our chained AST reader, we can just write out the DeclIDs. Otherwise,
213       // we need to resolve them to actual declarations.
214       if (Writer.Chain != Writer.Context->getExternalSource() &&
215           Common->LazySpecializations) {
216         D->LoadLazySpecializations();
217         assert(!Common->LazySpecializations);
218       }
219 
220       ArrayRef<DeclID> LazySpecializations;
221       if (auto *LS = Common->LazySpecializations)
222         LazySpecializations = llvm::makeArrayRef(LS + 1, LS[0]);
223 
224       // Add a slot to the record for the number of specializations.
225       unsigned I = Record.size();
226       Record.push_back(0);
227 
228       // AddFirstDeclFromEachModule might trigger deserialization, invalidating
229       // *Specializations iterators.
230       llvm::SmallVector<const Decl*, 16> Specs;
231       for (auto &Entry : Common->Specializations)
232         Specs.push_back(getSpecializationDecl(Entry));
233       for (auto &Entry : getPartialSpecializations(Common))
234         Specs.push_back(getSpecializationDecl(Entry));
235 
236       for (auto *D : Specs) {
237         assert(D->isCanonicalDecl() && "non-canonical decl in set");
238         AddFirstDeclFromEachModule(D, /*IncludeLocal*/true);
239       }
240       Record.append(LazySpecializations.begin(), LazySpecializations.end());
241 
242       // Update the size entry we added earlier.
243       Record[I] = Record.size() - I - 1;
244     }
245 
246     /// Ensure that this template specialization is associated with the specified
247     /// template on reload.
248     void RegisterTemplateSpecialization(const Decl *Template,
249                                         const Decl *Specialization) {
250       Template = Template->getCanonicalDecl();
251 
252       // If the canonical template is local, we'll write out this specialization
253       // when we emit it.
254       // FIXME: We can do the same thing if there is any local declaration of
255       // the template, to avoid emitting an update record.
256       if (!Template->isFromASTFile())
257         return;
258 
259       // We only need to associate the first local declaration of the
260       // specialization. The other declarations will get pulled in by it.
261       if (Writer.getFirstLocalDecl(Specialization) != Specialization)
262         return;
263 
264       Writer.DeclUpdates[Template].push_back(ASTWriter::DeclUpdate(
265           UPD_CXX_ADDED_TEMPLATE_SPECIALIZATION, Specialization));
266     }
267   };
268 }
269 
270 void ASTDeclWriter::Visit(Decl *D) {
271   DeclVisitor<ASTDeclWriter>::Visit(D);
272 
273   // Source locations require array (variable-length) abbreviations.  The
274   // abbreviation infrastructure requires that arrays are encoded last, so
275   // we handle it here in the case of those classes derived from DeclaratorDecl
276   if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D)) {
277     if (auto *TInfo = DD->getTypeSourceInfo())
278       Record.AddTypeLoc(TInfo->getTypeLoc());
279   }
280 
281   // Handle FunctionDecl's body here and write it after all other Stmts/Exprs
282   // have been written. We want it last because we will not read it back when
283   // retrieving it from the AST, we'll just lazily set the offset.
284   if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
285     Record.push_back(FD->doesThisDeclarationHaveABody());
286     if (FD->doesThisDeclarationHaveABody())
287       Record.AddFunctionDefinition(FD);
288   }
289 
290   // If this declaration is also a DeclContext, write blocks for the
291   // declarations that lexically stored inside its context and those
292   // declarations that are visible from its context.
293   if (DeclContext *DC = dyn_cast<DeclContext>(D))
294     VisitDeclContext(DC);
295 }
296 
297 void ASTDeclWriter::VisitDecl(Decl *D) {
298   Record.AddDeclRef(cast_or_null<Decl>(D->getDeclContext()));
299   if (D->getDeclContext() != D->getLexicalDeclContext())
300     Record.AddDeclRef(cast_or_null<Decl>(D->getLexicalDeclContext()));
301   else
302     Record.push_back(0);
303   Record.push_back(D->isInvalidDecl());
304   Record.push_back(D->hasAttrs());
305   if (D->hasAttrs())
306     Record.AddAttributes(D->getAttrs());
307   Record.push_back(D->isImplicit());
308   Record.push_back(D->isUsed(false));
309   Record.push_back(D->isReferenced());
310   Record.push_back(D->isTopLevelDeclInObjCContainer());
311   Record.push_back(D->getAccess());
312   Record.push_back(D->isModulePrivate());
313   Record.push_back(Writer.getSubmoduleID(D->getOwningModule()));
314 
315   // If this declaration injected a name into a context different from its
316   // lexical context, and that context is an imported namespace, we need to
317   // update its visible declarations to include this name.
318   //
319   // This happens when we instantiate a class with a friend declaration or a
320   // function with a local extern declaration, for instance.
321   //
322   // FIXME: Can we handle this in AddedVisibleDecl instead?
323   if (D->isOutOfLine()) {
324     auto *DC = D->getDeclContext();
325     while (auto *NS = dyn_cast<NamespaceDecl>(DC->getRedeclContext())) {
326       if (!NS->isFromASTFile())
327         break;
328       Writer.UpdatedDeclContexts.insert(NS->getPrimaryContext());
329       if (!NS->isInlineNamespace())
330         break;
331       DC = NS->getParent();
332     }
333   }
334 }
335 
336 void ASTDeclWriter::VisitPragmaCommentDecl(PragmaCommentDecl *D) {
337   StringRef Arg = D->getArg();
338   Record.push_back(Arg.size());
339   VisitDecl(D);
340   Record.AddSourceLocation(D->getBeginLoc());
341   Record.push_back(D->getCommentKind());
342   Record.AddString(Arg);
343   Code = serialization::DECL_PRAGMA_COMMENT;
344 }
345 
346 void ASTDeclWriter::VisitPragmaDetectMismatchDecl(
347     PragmaDetectMismatchDecl *D) {
348   StringRef Name = D->getName();
349   StringRef Value = D->getValue();
350   Record.push_back(Name.size() + 1 + Value.size());
351   VisitDecl(D);
352   Record.AddSourceLocation(D->getBeginLoc());
353   Record.AddString(Name);
354   Record.AddString(Value);
355   Code = serialization::DECL_PRAGMA_DETECT_MISMATCH;
356 }
357 
358 void ASTDeclWriter::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
359   llvm_unreachable("Translation units aren't directly serialized");
360 }
361 
362 void ASTDeclWriter::VisitNamedDecl(NamedDecl *D) {
363   VisitDecl(D);
364   Record.AddDeclarationName(D->getDeclName());
365   Record.push_back(needsAnonymousDeclarationNumber(D)
366                        ? Writer.getAnonymousDeclarationNumber(D)
367                        : 0);
368 }
369 
370 void ASTDeclWriter::VisitTypeDecl(TypeDecl *D) {
371   VisitNamedDecl(D);
372   Record.AddSourceLocation(D->getBeginLoc());
373   Record.AddTypeRef(QualType(D->getTypeForDecl(), 0));
374 }
375 
376 void ASTDeclWriter::VisitTypedefNameDecl(TypedefNameDecl *D) {
377   VisitRedeclarable(D);
378   VisitTypeDecl(D);
379   Record.AddTypeSourceInfo(D->getTypeSourceInfo());
380   Record.push_back(D->isModed());
381   if (D->isModed())
382     Record.AddTypeRef(D->getUnderlyingType());
383   Record.AddDeclRef(D->getAnonDeclWithTypedefName(false));
384 }
385 
386 void ASTDeclWriter::VisitTypedefDecl(TypedefDecl *D) {
387   VisitTypedefNameDecl(D);
388   if (D->getDeclContext() == D->getLexicalDeclContext() &&
389       !D->hasAttrs() &&
390       !D->isImplicit() &&
391       D->getFirstDecl() == D->getMostRecentDecl() &&
392       !D->isInvalidDecl() &&
393       !D->isTopLevelDeclInObjCContainer() &&
394       !D->isModulePrivate() &&
395       !needsAnonymousDeclarationNumber(D) &&
396       D->getDeclName().getNameKind() == DeclarationName::Identifier)
397     AbbrevToUse = Writer.getDeclTypedefAbbrev();
398 
399   Code = serialization::DECL_TYPEDEF;
400 }
401 
402 void ASTDeclWriter::VisitTypeAliasDecl(TypeAliasDecl *D) {
403   VisitTypedefNameDecl(D);
404   Record.AddDeclRef(D->getDescribedAliasTemplate());
405   Code = serialization::DECL_TYPEALIAS;
406 }
407 
408 void ASTDeclWriter::VisitTagDecl(TagDecl *D) {
409   VisitRedeclarable(D);
410   VisitTypeDecl(D);
411   Record.push_back(D->getIdentifierNamespace());
412   Record.push_back((unsigned)D->getTagKind()); // FIXME: stable encoding
413   if (!isa<CXXRecordDecl>(D))
414     Record.push_back(D->isCompleteDefinition());
415   Record.push_back(D->isEmbeddedInDeclarator());
416   Record.push_back(D->isFreeStanding());
417   Record.push_back(D->isCompleteDefinitionRequired());
418   Record.AddSourceRange(D->getBraceRange());
419 
420   if (D->hasExtInfo()) {
421     Record.push_back(1);
422     Record.AddQualifierInfo(*D->getExtInfo());
423   } else if (auto *TD = D->getTypedefNameForAnonDecl()) {
424     Record.push_back(2);
425     Record.AddDeclRef(TD);
426     Record.AddIdentifierRef(TD->getDeclName().getAsIdentifierInfo());
427   } else {
428     Record.push_back(0);
429   }
430 }
431 
432 void ASTDeclWriter::VisitEnumDecl(EnumDecl *D) {
433   VisitTagDecl(D);
434   Record.AddTypeSourceInfo(D->getIntegerTypeSourceInfo());
435   if (!D->getIntegerTypeSourceInfo())
436     Record.AddTypeRef(D->getIntegerType());
437   Record.AddTypeRef(D->getPromotionType());
438   Record.push_back(D->getNumPositiveBits());
439   Record.push_back(D->getNumNegativeBits());
440   Record.push_back(D->isScoped());
441   Record.push_back(D->isScopedUsingClassTag());
442   Record.push_back(D->isFixed());
443   Record.push_back(D->getODRHash());
444 
445   if (MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo()) {
446     Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
447     Record.push_back(MemberInfo->getTemplateSpecializationKind());
448     Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
449   } else {
450     Record.AddDeclRef(nullptr);
451   }
452 
453   if (D->getDeclContext() == D->getLexicalDeclContext() &&
454       !D->hasAttrs() &&
455       !D->isImplicit() &&
456       !D->isUsed(false) &&
457       !D->hasExtInfo() &&
458       !D->getTypedefNameForAnonDecl() &&
459       D->getFirstDecl() == D->getMostRecentDecl() &&
460       !D->isInvalidDecl() &&
461       !D->isReferenced() &&
462       !D->isTopLevelDeclInObjCContainer() &&
463       D->getAccess() == AS_none &&
464       !D->isModulePrivate() &&
465       !CXXRecordDecl::classofKind(D->getKind()) &&
466       !D->getIntegerTypeSourceInfo() &&
467       !D->getMemberSpecializationInfo() &&
468       !needsAnonymousDeclarationNumber(D) &&
469       D->getDeclName().getNameKind() == DeclarationName::Identifier)
470     AbbrevToUse = Writer.getDeclEnumAbbrev();
471 
472   Code = serialization::DECL_ENUM;
473 }
474 
475 void ASTDeclWriter::VisitRecordDecl(RecordDecl *D) {
476   VisitTagDecl(D);
477   Record.push_back(D->hasFlexibleArrayMember());
478   Record.push_back(D->isAnonymousStructOrUnion());
479   Record.push_back(D->hasObjectMember());
480   Record.push_back(D->hasVolatileMember());
481   Record.push_back(D->isNonTrivialToPrimitiveDefaultInitialize());
482   Record.push_back(D->isNonTrivialToPrimitiveCopy());
483   Record.push_back(D->isNonTrivialToPrimitiveDestroy());
484   Record.push_back(D->hasNonTrivialToPrimitiveDefaultInitializeCUnion());
485   Record.push_back(D->hasNonTrivialToPrimitiveDestructCUnion());
486   Record.push_back(D->hasNonTrivialToPrimitiveCopyCUnion());
487   Record.push_back(D->isParamDestroyedInCallee());
488   Record.push_back(D->getArgPassingRestrictions());
489 
490   if (D->getDeclContext() == D->getLexicalDeclContext() &&
491       !D->hasAttrs() &&
492       !D->isImplicit() &&
493       !D->isUsed(false) &&
494       !D->hasExtInfo() &&
495       !D->getTypedefNameForAnonDecl() &&
496       D->getFirstDecl() == D->getMostRecentDecl() &&
497       !D->isInvalidDecl() &&
498       !D->isReferenced() &&
499       !D->isTopLevelDeclInObjCContainer() &&
500       D->getAccess() == AS_none &&
501       !D->isModulePrivate() &&
502       !CXXRecordDecl::classofKind(D->getKind()) &&
503       !needsAnonymousDeclarationNumber(D) &&
504       D->getDeclName().getNameKind() == DeclarationName::Identifier)
505     AbbrevToUse = Writer.getDeclRecordAbbrev();
506 
507   Code = serialization::DECL_RECORD;
508 }
509 
510 void ASTDeclWriter::VisitValueDecl(ValueDecl *D) {
511   VisitNamedDecl(D);
512   Record.AddTypeRef(D->getType());
513 }
514 
515 void ASTDeclWriter::VisitEnumConstantDecl(EnumConstantDecl *D) {
516   VisitValueDecl(D);
517   Record.push_back(D->getInitExpr()? 1 : 0);
518   if (D->getInitExpr())
519     Record.AddStmt(D->getInitExpr());
520   Record.AddAPSInt(D->getInitVal());
521 
522   Code = serialization::DECL_ENUM_CONSTANT;
523 }
524 
525 void ASTDeclWriter::VisitDeclaratorDecl(DeclaratorDecl *D) {
526   VisitValueDecl(D);
527   Record.AddSourceLocation(D->getInnerLocStart());
528   Record.push_back(D->hasExtInfo());
529   if (D->hasExtInfo()) {
530     DeclaratorDecl::ExtInfo *Info = D->getExtInfo();
531     Record.AddQualifierInfo(*Info);
532     Record.AddStmt(Info->TrailingRequiresClause);
533   }
534   // The location information is deferred until the end of the record.
535   Record.AddTypeRef(D->getTypeSourceInfo() ? D->getTypeSourceInfo()->getType()
536                                            : QualType());
537 }
538 
539 void ASTDeclWriter::VisitFunctionDecl(FunctionDecl *D) {
540   VisitRedeclarable(D);
541   VisitDeclaratorDecl(D);
542   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
543   Record.push_back(D->getIdentifierNamespace());
544 
545   // FunctionDecl's body is handled last at ASTWriterDecl::Visit,
546   // after everything else is written.
547   Record.push_back(static_cast<int>(D->getStorageClass())); // FIXME: stable encoding
548   Record.push_back(D->isInlineSpecified());
549   Record.push_back(D->isInlined());
550   Record.push_back(D->isVirtualAsWritten());
551   Record.push_back(D->isPure());
552   Record.push_back(D->hasInheritedPrototype());
553   Record.push_back(D->hasWrittenPrototype());
554   Record.push_back(D->isDeletedBit());
555   Record.push_back(D->isTrivial());
556   Record.push_back(D->isTrivialForCall());
557   Record.push_back(D->isDefaulted());
558   Record.push_back(D->isExplicitlyDefaulted());
559   Record.push_back(D->hasImplicitReturnZero());
560   Record.push_back(static_cast<uint64_t>(D->getConstexprKind()));
561   Record.push_back(D->usesSEHTry());
562   Record.push_back(D->hasSkippedBody());
563   Record.push_back(D->isMultiVersion());
564   Record.push_back(D->isLateTemplateParsed());
565   Record.push_back(D->getLinkageInternal());
566   Record.AddSourceLocation(D->getEndLoc());
567 
568   Record.push_back(D->getODRHash());
569 
570   if (D->isDefaulted()) {
571     if (auto *FDI = D->getDefaultedFunctionInfo()) {
572       Record.push_back(FDI->getUnqualifiedLookups().size());
573       for (DeclAccessPair P : FDI->getUnqualifiedLookups()) {
574         Record.AddDeclRef(P.getDecl());
575         Record.push_back(P.getAccess());
576       }
577     } else {
578       Record.push_back(0);
579     }
580   }
581 
582   Record.push_back(D->getTemplatedKind());
583   switch (D->getTemplatedKind()) {
584   case FunctionDecl::TK_NonTemplate:
585     break;
586   case FunctionDecl::TK_FunctionTemplate:
587     Record.AddDeclRef(D->getDescribedFunctionTemplate());
588     break;
589   case FunctionDecl::TK_MemberSpecialization: {
590     MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo();
591     Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
592     Record.push_back(MemberInfo->getTemplateSpecializationKind());
593     Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
594     break;
595   }
596   case FunctionDecl::TK_FunctionTemplateSpecialization: {
597     FunctionTemplateSpecializationInfo *
598       FTSInfo = D->getTemplateSpecializationInfo();
599 
600     RegisterTemplateSpecialization(FTSInfo->getTemplate(), D);
601 
602     Record.AddDeclRef(FTSInfo->getTemplate());
603     Record.push_back(FTSInfo->getTemplateSpecializationKind());
604 
605     // Template arguments.
606     Record.AddTemplateArgumentList(FTSInfo->TemplateArguments);
607 
608     // Template args as written.
609     Record.push_back(FTSInfo->TemplateArgumentsAsWritten != nullptr);
610     if (FTSInfo->TemplateArgumentsAsWritten) {
611       Record.push_back(FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs);
612       for (int i=0, e = FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs;
613              i!=e; ++i)
614         Record.AddTemplateArgumentLoc(
615             (*FTSInfo->TemplateArgumentsAsWritten)[i]);
616       Record.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->LAngleLoc);
617       Record.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->RAngleLoc);
618     }
619 
620     Record.AddSourceLocation(FTSInfo->getPointOfInstantiation());
621 
622     if (MemberSpecializationInfo *MemberInfo =
623         FTSInfo->getMemberSpecializationInfo()) {
624       Record.push_back(1);
625       Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
626       Record.push_back(MemberInfo->getTemplateSpecializationKind());
627       Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
628     } else {
629       Record.push_back(0);
630     }
631 
632     if (D->isCanonicalDecl()) {
633       // Write the template that contains the specializations set. We will
634       // add a FunctionTemplateSpecializationInfo to it when reading.
635       Record.AddDeclRef(FTSInfo->getTemplate()->getCanonicalDecl());
636     }
637     break;
638   }
639   case FunctionDecl::TK_DependentFunctionTemplateSpecialization: {
640     DependentFunctionTemplateSpecializationInfo *
641       DFTSInfo = D->getDependentSpecializationInfo();
642 
643     // Templates.
644     Record.push_back(DFTSInfo->getNumTemplates());
645     for (int i=0, e = DFTSInfo->getNumTemplates(); i != e; ++i)
646       Record.AddDeclRef(DFTSInfo->getTemplate(i));
647 
648     // Templates args.
649     Record.push_back(DFTSInfo->getNumTemplateArgs());
650     for (int i=0, e = DFTSInfo->getNumTemplateArgs(); i != e; ++i)
651       Record.AddTemplateArgumentLoc(DFTSInfo->getTemplateArg(i));
652     Record.AddSourceLocation(DFTSInfo->getLAngleLoc());
653     Record.AddSourceLocation(DFTSInfo->getRAngleLoc());
654     break;
655   }
656   }
657 
658   Record.push_back(D->param_size());
659   for (auto P : D->parameters())
660     Record.AddDeclRef(P);
661   Code = serialization::DECL_FUNCTION;
662 }
663 
664 static void addExplicitSpecifier(ExplicitSpecifier ES,
665                                  ASTRecordWriter &Record) {
666   uint64_t Kind = static_cast<uint64_t>(ES.getKind());
667   Kind = Kind << 1 | static_cast<bool>(ES.getExpr());
668   Record.push_back(Kind);
669   if (ES.getExpr()) {
670     Record.AddStmt(ES.getExpr());
671   }
672 }
673 
674 void ASTDeclWriter::VisitCXXDeductionGuideDecl(CXXDeductionGuideDecl *D) {
675   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
676   Record.AddDeclRef(D->Ctor);
677   VisitFunctionDecl(D);
678   Record.push_back(D->isCopyDeductionCandidate());
679   Code = serialization::DECL_CXX_DEDUCTION_GUIDE;
680 }
681 
682 void ASTDeclWriter::VisitObjCMethodDecl(ObjCMethodDecl *D) {
683   VisitNamedDecl(D);
684   // FIXME: convert to LazyStmtPtr?
685   // Unlike C/C++, method bodies will never be in header files.
686   bool HasBodyStuff = D->getBody() != nullptr;
687   Record.push_back(HasBodyStuff);
688   if (HasBodyStuff) {
689     Record.AddStmt(D->getBody());
690   }
691   Record.AddDeclRef(D->getSelfDecl());
692   Record.AddDeclRef(D->getCmdDecl());
693   Record.push_back(D->isInstanceMethod());
694   Record.push_back(D->isVariadic());
695   Record.push_back(D->isPropertyAccessor());
696   Record.push_back(D->isSynthesizedAccessorStub());
697   Record.push_back(D->isDefined());
698   Record.push_back(D->isOverriding());
699   Record.push_back(D->hasSkippedBody());
700 
701   Record.push_back(D->isRedeclaration());
702   Record.push_back(D->hasRedeclaration());
703   if (D->hasRedeclaration()) {
704     assert(Context.getObjCMethodRedeclaration(D));
705     Record.AddDeclRef(Context.getObjCMethodRedeclaration(D));
706   }
707 
708   // FIXME: stable encoding for @required/@optional
709   Record.push_back(D->getImplementationControl());
710   // FIXME: stable encoding for in/out/inout/bycopy/byref/oneway/nullability
711   Record.push_back(D->getObjCDeclQualifier());
712   Record.push_back(D->hasRelatedResultType());
713   Record.AddTypeRef(D->getReturnType());
714   Record.AddTypeSourceInfo(D->getReturnTypeSourceInfo());
715   Record.AddSourceLocation(D->getEndLoc());
716   Record.push_back(D->param_size());
717   for (const auto *P : D->parameters())
718     Record.AddDeclRef(P);
719 
720   Record.push_back(D->getSelLocsKind());
721   unsigned NumStoredSelLocs = D->getNumStoredSelLocs();
722   SourceLocation *SelLocs = D->getStoredSelLocs();
723   Record.push_back(NumStoredSelLocs);
724   for (unsigned i = 0; i != NumStoredSelLocs; ++i)
725     Record.AddSourceLocation(SelLocs[i]);
726 
727   Code = serialization::DECL_OBJC_METHOD;
728 }
729 
730 void ASTDeclWriter::VisitObjCTypeParamDecl(ObjCTypeParamDecl *D) {
731   VisitTypedefNameDecl(D);
732   Record.push_back(D->Variance);
733   Record.push_back(D->Index);
734   Record.AddSourceLocation(D->VarianceLoc);
735   Record.AddSourceLocation(D->ColonLoc);
736 
737   Code = serialization::DECL_OBJC_TYPE_PARAM;
738 }
739 
740 void ASTDeclWriter::VisitObjCContainerDecl(ObjCContainerDecl *D) {
741   VisitNamedDecl(D);
742   Record.AddSourceLocation(D->getAtStartLoc());
743   Record.AddSourceRange(D->getAtEndRange());
744   // Abstract class (no need to define a stable serialization::DECL code).
745 }
746 
747 void ASTDeclWriter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
748   VisitRedeclarable(D);
749   VisitObjCContainerDecl(D);
750   Record.AddTypeRef(QualType(D->getTypeForDecl(), 0));
751   AddObjCTypeParamList(D->TypeParamList);
752 
753   Record.push_back(D->isThisDeclarationADefinition());
754   if (D->isThisDeclarationADefinition()) {
755     // Write the DefinitionData
756     ObjCInterfaceDecl::DefinitionData &Data = D->data();
757 
758     Record.AddTypeSourceInfo(D->getSuperClassTInfo());
759     Record.AddSourceLocation(D->getEndOfDefinitionLoc());
760     Record.push_back(Data.HasDesignatedInitializers);
761 
762     // Write out the protocols that are directly referenced by the @interface.
763     Record.push_back(Data.ReferencedProtocols.size());
764     for (const auto *P : D->protocols())
765       Record.AddDeclRef(P);
766     for (const auto &PL : D->protocol_locs())
767       Record.AddSourceLocation(PL);
768 
769     // Write out the protocols that are transitively referenced.
770     Record.push_back(Data.AllReferencedProtocols.size());
771     for (ObjCList<ObjCProtocolDecl>::iterator
772               P = Data.AllReferencedProtocols.begin(),
773            PEnd = Data.AllReferencedProtocols.end();
774          P != PEnd; ++P)
775       Record.AddDeclRef(*P);
776 
777 
778     if (ObjCCategoryDecl *Cat = D->getCategoryListRaw()) {
779       // Ensure that we write out the set of categories for this class.
780       Writer.ObjCClassesWithCategories.insert(D);
781 
782       // Make sure that the categories get serialized.
783       for (; Cat; Cat = Cat->getNextClassCategoryRaw())
784         (void)Writer.GetDeclRef(Cat);
785     }
786   }
787 
788   Code = serialization::DECL_OBJC_INTERFACE;
789 }
790 
791 void ASTDeclWriter::VisitObjCIvarDecl(ObjCIvarDecl *D) {
792   VisitFieldDecl(D);
793   // FIXME: stable encoding for @public/@private/@protected/@package
794   Record.push_back(D->getAccessControl());
795   Record.push_back(D->getSynthesize());
796 
797   if (D->getDeclContext() == D->getLexicalDeclContext() &&
798       !D->hasAttrs() &&
799       !D->isImplicit() &&
800       !D->isUsed(false) &&
801       !D->isInvalidDecl() &&
802       !D->isReferenced() &&
803       !D->isModulePrivate() &&
804       !D->getBitWidth() &&
805       !D->hasExtInfo() &&
806       D->getDeclName())
807     AbbrevToUse = Writer.getDeclObjCIvarAbbrev();
808 
809   Code = serialization::DECL_OBJC_IVAR;
810 }
811 
812 void ASTDeclWriter::VisitObjCProtocolDecl(ObjCProtocolDecl *D) {
813   VisitRedeclarable(D);
814   VisitObjCContainerDecl(D);
815 
816   Record.push_back(D->isThisDeclarationADefinition());
817   if (D->isThisDeclarationADefinition()) {
818     Record.push_back(D->protocol_size());
819     for (const auto *I : D->protocols())
820       Record.AddDeclRef(I);
821     for (const auto &PL : D->protocol_locs())
822       Record.AddSourceLocation(PL);
823   }
824 
825   Code = serialization::DECL_OBJC_PROTOCOL;
826 }
827 
828 void ASTDeclWriter::VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D) {
829   VisitFieldDecl(D);
830   Code = serialization::DECL_OBJC_AT_DEFS_FIELD;
831 }
832 
833 void ASTDeclWriter::VisitObjCCategoryDecl(ObjCCategoryDecl *D) {
834   VisitObjCContainerDecl(D);
835   Record.AddSourceLocation(D->getCategoryNameLoc());
836   Record.AddSourceLocation(D->getIvarLBraceLoc());
837   Record.AddSourceLocation(D->getIvarRBraceLoc());
838   Record.AddDeclRef(D->getClassInterface());
839   AddObjCTypeParamList(D->TypeParamList);
840   Record.push_back(D->protocol_size());
841   for (const auto *I : D->protocols())
842     Record.AddDeclRef(I);
843   for (const auto &PL : D->protocol_locs())
844     Record.AddSourceLocation(PL);
845   Code = serialization::DECL_OBJC_CATEGORY;
846 }
847 
848 void ASTDeclWriter::VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D) {
849   VisitNamedDecl(D);
850   Record.AddDeclRef(D->getClassInterface());
851   Code = serialization::DECL_OBJC_COMPATIBLE_ALIAS;
852 }
853 
854 void ASTDeclWriter::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
855   VisitNamedDecl(D);
856   Record.AddSourceLocation(D->getAtLoc());
857   Record.AddSourceLocation(D->getLParenLoc());
858   Record.AddTypeRef(D->getType());
859   Record.AddTypeSourceInfo(D->getTypeSourceInfo());
860   // FIXME: stable encoding
861   Record.push_back((unsigned)D->getPropertyAttributes());
862   Record.push_back((unsigned)D->getPropertyAttributesAsWritten());
863   // FIXME: stable encoding
864   Record.push_back((unsigned)D->getPropertyImplementation());
865   Record.AddDeclarationName(D->getGetterName());
866   Record.AddSourceLocation(D->getGetterNameLoc());
867   Record.AddDeclarationName(D->getSetterName());
868   Record.AddSourceLocation(D->getSetterNameLoc());
869   Record.AddDeclRef(D->getGetterMethodDecl());
870   Record.AddDeclRef(D->getSetterMethodDecl());
871   Record.AddDeclRef(D->getPropertyIvarDecl());
872   Code = serialization::DECL_OBJC_PROPERTY;
873 }
874 
875 void ASTDeclWriter::VisitObjCImplDecl(ObjCImplDecl *D) {
876   VisitObjCContainerDecl(D);
877   Record.AddDeclRef(D->getClassInterface());
878   // Abstract class (no need to define a stable serialization::DECL code).
879 }
880 
881 void ASTDeclWriter::VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D) {
882   VisitObjCImplDecl(D);
883   Record.AddSourceLocation(D->getCategoryNameLoc());
884   Code = serialization::DECL_OBJC_CATEGORY_IMPL;
885 }
886 
887 void ASTDeclWriter::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
888   VisitObjCImplDecl(D);
889   Record.AddDeclRef(D->getSuperClass());
890   Record.AddSourceLocation(D->getSuperClassLoc());
891   Record.AddSourceLocation(D->getIvarLBraceLoc());
892   Record.AddSourceLocation(D->getIvarRBraceLoc());
893   Record.push_back(D->hasNonZeroConstructors());
894   Record.push_back(D->hasDestructors());
895   Record.push_back(D->NumIvarInitializers);
896   if (D->NumIvarInitializers)
897     Record.AddCXXCtorInitializers(
898         llvm::makeArrayRef(D->init_begin(), D->init_end()));
899   Code = serialization::DECL_OBJC_IMPLEMENTATION;
900 }
901 
902 void ASTDeclWriter::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
903   VisitDecl(D);
904   Record.AddSourceLocation(D->getBeginLoc());
905   Record.AddDeclRef(D->getPropertyDecl());
906   Record.AddDeclRef(D->getPropertyIvarDecl());
907   Record.AddSourceLocation(D->getPropertyIvarDeclLoc());
908   Record.AddDeclRef(D->getGetterMethodDecl());
909   Record.AddDeclRef(D->getSetterMethodDecl());
910   Record.AddStmt(D->getGetterCXXConstructor());
911   Record.AddStmt(D->getSetterCXXAssignment());
912   Code = serialization::DECL_OBJC_PROPERTY_IMPL;
913 }
914 
915 void ASTDeclWriter::VisitFieldDecl(FieldDecl *D) {
916   VisitDeclaratorDecl(D);
917   Record.push_back(D->isMutable());
918 
919   FieldDecl::InitStorageKind ISK = D->InitStorage.getInt();
920   Record.push_back(ISK);
921   if (ISK == FieldDecl::ISK_CapturedVLAType)
922     Record.AddTypeRef(QualType(D->getCapturedVLAType(), 0));
923   else if (ISK)
924     Record.AddStmt(D->getInClassInitializer());
925 
926   Record.AddStmt(D->getBitWidth());
927 
928   if (!D->getDeclName())
929     Record.AddDeclRef(Context.getInstantiatedFromUnnamedFieldDecl(D));
930 
931   if (D->getDeclContext() == D->getLexicalDeclContext() &&
932       !D->hasAttrs() &&
933       !D->isImplicit() &&
934       !D->isUsed(false) &&
935       !D->isInvalidDecl() &&
936       !D->isReferenced() &&
937       !D->isTopLevelDeclInObjCContainer() &&
938       !D->isModulePrivate() &&
939       !D->getBitWidth() &&
940       !D->hasInClassInitializer() &&
941       !D->hasCapturedVLAType() &&
942       !D->hasExtInfo() &&
943       !ObjCIvarDecl::classofKind(D->getKind()) &&
944       !ObjCAtDefsFieldDecl::classofKind(D->getKind()) &&
945       D->getDeclName())
946     AbbrevToUse = Writer.getDeclFieldAbbrev();
947 
948   Code = serialization::DECL_FIELD;
949 }
950 
951 void ASTDeclWriter::VisitMSPropertyDecl(MSPropertyDecl *D) {
952   VisitDeclaratorDecl(D);
953   Record.AddIdentifierRef(D->getGetterId());
954   Record.AddIdentifierRef(D->getSetterId());
955   Code = serialization::DECL_MS_PROPERTY;
956 }
957 
958 void ASTDeclWriter::VisitMSGuidDecl(MSGuidDecl *D) {
959   VisitValueDecl(D);
960   MSGuidDecl::Parts Parts = D->getParts();
961   Record.push_back(Parts.Part1);
962   Record.push_back(Parts.Part2);
963   Record.push_back(Parts.Part3);
964   for (auto C : Parts.Part4And5)
965     Record.push_back(C);
966   Code = serialization::DECL_MS_GUID;
967 }
968 
969 void ASTDeclWriter::VisitTemplateParamObjectDecl(TemplateParamObjectDecl *D) {
970   VisitValueDecl(D);
971   Record.AddAPValue(D->getValue());
972   Code = serialization::DECL_TEMPLATE_PARAM_OBJECT;
973 }
974 
975 void ASTDeclWriter::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
976   VisitValueDecl(D);
977   Record.push_back(D->getChainingSize());
978 
979   for (const auto *P : D->chain())
980     Record.AddDeclRef(P);
981   Code = serialization::DECL_INDIRECTFIELD;
982 }
983 
984 void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
985   VisitRedeclarable(D);
986   VisitDeclaratorDecl(D);
987   Record.push_back(D->getStorageClass());
988   Record.push_back(D->getTSCSpec());
989   Record.push_back(D->getInitStyle());
990   Record.push_back(D->isARCPseudoStrong());
991   if (!isa<ParmVarDecl>(D)) {
992     Record.push_back(D->isThisDeclarationADemotedDefinition());
993     Record.push_back(D->isExceptionVariable());
994     Record.push_back(D->isNRVOVariable());
995     Record.push_back(D->isCXXForRangeDecl());
996     Record.push_back(D->isObjCForDecl());
997     Record.push_back(D->isInline());
998     Record.push_back(D->isInlineSpecified());
999     Record.push_back(D->isConstexpr());
1000     Record.push_back(D->isInitCapture());
1001     Record.push_back(D->isPreviousDeclInSameBlockScope());
1002     if (const auto *IPD = dyn_cast<ImplicitParamDecl>(D))
1003       Record.push_back(static_cast<unsigned>(IPD->getParameterKind()));
1004     else
1005       Record.push_back(0);
1006     Record.push_back(D->isEscapingByref());
1007   }
1008   Record.push_back(D->getLinkageInternal());
1009 
1010   Record.AddVarDeclInit(D);
1011 
1012   if (D->hasAttr<BlocksAttr>() && D->getType()->getAsCXXRecordDecl()) {
1013     BlockVarCopyInit Init = Writer.Context->getBlockVarCopyInit(D);
1014     Record.AddStmt(Init.getCopyExpr());
1015     if (Init.getCopyExpr())
1016       Record.push_back(Init.canThrow());
1017   }
1018 
1019   if (D->getStorageDuration() == SD_Static) {
1020     bool ModulesCodegen = false;
1021     if (Writer.WritingModule &&
1022         !D->getDescribedVarTemplate() && !D->getMemberSpecializationInfo() &&
1023         !isa<VarTemplateSpecializationDecl>(D)) {
1024       // When building a C++ Modules TS module interface unit, a strong
1025       // definition in the module interface is provided by the compilation of
1026       // that module interface unit, not by its users. (Inline variables are
1027       // still emitted in module users.)
1028       ModulesCodegen =
1029           (Writer.WritingModule->Kind == Module::ModuleInterfaceUnit ||
1030            (D->hasAttr<DLLExportAttr>() &&
1031             Writer.Context->getLangOpts().BuildingPCHWithObjectFile)) &&
1032           Writer.Context->GetGVALinkageForVariable(D) == GVA_StrongExternal;
1033     }
1034     Record.push_back(ModulesCodegen);
1035     if (ModulesCodegen)
1036       Writer.ModularCodegenDecls.push_back(Writer.GetDeclRef(D));
1037   }
1038 
1039   enum {
1040     VarNotTemplate = 0, VarTemplate, StaticDataMemberSpecialization
1041   };
1042   if (VarTemplateDecl *TemplD = D->getDescribedVarTemplate()) {
1043     Record.push_back(VarTemplate);
1044     Record.AddDeclRef(TemplD);
1045   } else if (MemberSpecializationInfo *SpecInfo
1046                = D->getMemberSpecializationInfo()) {
1047     Record.push_back(StaticDataMemberSpecialization);
1048     Record.AddDeclRef(SpecInfo->getInstantiatedFrom());
1049     Record.push_back(SpecInfo->getTemplateSpecializationKind());
1050     Record.AddSourceLocation(SpecInfo->getPointOfInstantiation());
1051   } else {
1052     Record.push_back(VarNotTemplate);
1053   }
1054 
1055   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1056       !D->hasAttrs() &&
1057       !D->isImplicit() &&
1058       !D->isUsed(false) &&
1059       !D->isInvalidDecl() &&
1060       !D->isReferenced() &&
1061       !D->isTopLevelDeclInObjCContainer() &&
1062       D->getAccess() == AS_none &&
1063       !D->isModulePrivate() &&
1064       !needsAnonymousDeclarationNumber(D) &&
1065       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1066       !D->hasExtInfo() &&
1067       D->getFirstDecl() == D->getMostRecentDecl() &&
1068       D->getKind() == Decl::Var &&
1069       !D->isInline() &&
1070       !D->isConstexpr() &&
1071       !D->isInitCapture() &&
1072       !D->isPreviousDeclInSameBlockScope() &&
1073       !(D->hasAttr<BlocksAttr>() && D->getType()->getAsCXXRecordDecl()) &&
1074       !D->isEscapingByref() &&
1075       D->getStorageDuration() != SD_Static &&
1076       !D->getMemberSpecializationInfo())
1077     AbbrevToUse = Writer.getDeclVarAbbrev();
1078 
1079   Code = serialization::DECL_VAR;
1080 }
1081 
1082 void ASTDeclWriter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
1083   VisitVarDecl(D);
1084   Code = serialization::DECL_IMPLICIT_PARAM;
1085 }
1086 
1087 void ASTDeclWriter::VisitParmVarDecl(ParmVarDecl *D) {
1088   VisitVarDecl(D);
1089   Record.push_back(D->isObjCMethodParameter());
1090   Record.push_back(D->getFunctionScopeDepth());
1091   Record.push_back(D->getFunctionScopeIndex());
1092   Record.push_back(D->getObjCDeclQualifier()); // FIXME: stable encoding
1093   Record.push_back(D->isKNRPromoted());
1094   Record.push_back(D->hasInheritedDefaultArg());
1095   Record.push_back(D->hasUninstantiatedDefaultArg());
1096   if (D->hasUninstantiatedDefaultArg())
1097     Record.AddStmt(D->getUninstantiatedDefaultArg());
1098   Code = serialization::DECL_PARM_VAR;
1099 
1100   // If the assumptions about the DECL_PARM_VAR abbrev are true, use it.  Here
1101   // we dynamically check for the properties that we optimize for, but don't
1102   // know are true of all PARM_VAR_DECLs.
1103   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1104       !D->hasAttrs() &&
1105       !D->hasExtInfo() &&
1106       !D->isImplicit() &&
1107       !D->isUsed(false) &&
1108       !D->isInvalidDecl() &&
1109       !D->isReferenced() &&
1110       D->getAccess() == AS_none &&
1111       !D->isModulePrivate() &&
1112       D->getStorageClass() == 0 &&
1113       D->getInitStyle() == VarDecl::CInit && // Can params have anything else?
1114       D->getFunctionScopeDepth() == 0 &&
1115       D->getObjCDeclQualifier() == 0 &&
1116       !D->isKNRPromoted() &&
1117       !D->hasInheritedDefaultArg() &&
1118       D->getInit() == nullptr &&
1119       !D->hasUninstantiatedDefaultArg())  // No default expr.
1120     AbbrevToUse = Writer.getDeclParmVarAbbrev();
1121 
1122   // Check things we know are true of *every* PARM_VAR_DECL, which is more than
1123   // just us assuming it.
1124   assert(!D->getTSCSpec() && "PARM_VAR_DECL can't use TLS");
1125   assert(!D->isThisDeclarationADemotedDefinition()
1126          && "PARM_VAR_DECL can't be demoted definition.");
1127   assert(D->getAccess() == AS_none && "PARM_VAR_DECL can't be public/private");
1128   assert(!D->isExceptionVariable() && "PARM_VAR_DECL can't be exception var");
1129   assert(D->getPreviousDecl() == nullptr && "PARM_VAR_DECL can't be redecl");
1130   assert(!D->isStaticDataMember() &&
1131          "PARM_VAR_DECL can't be static data member");
1132 }
1133 
1134 void ASTDeclWriter::VisitDecompositionDecl(DecompositionDecl *D) {
1135   // Record the number of bindings first to simplify deserialization.
1136   Record.push_back(D->bindings().size());
1137 
1138   VisitVarDecl(D);
1139   for (auto *B : D->bindings())
1140     Record.AddDeclRef(B);
1141   Code = serialization::DECL_DECOMPOSITION;
1142 }
1143 
1144 void ASTDeclWriter::VisitBindingDecl(BindingDecl *D) {
1145   VisitValueDecl(D);
1146   Record.AddStmt(D->getBinding());
1147   Code = serialization::DECL_BINDING;
1148 }
1149 
1150 void ASTDeclWriter::VisitFileScopeAsmDecl(FileScopeAsmDecl *D) {
1151   VisitDecl(D);
1152   Record.AddStmt(D->getAsmString());
1153   Record.AddSourceLocation(D->getRParenLoc());
1154   Code = serialization::DECL_FILE_SCOPE_ASM;
1155 }
1156 
1157 void ASTDeclWriter::VisitEmptyDecl(EmptyDecl *D) {
1158   VisitDecl(D);
1159   Code = serialization::DECL_EMPTY;
1160 }
1161 
1162 void ASTDeclWriter::VisitLifetimeExtendedTemporaryDecl(
1163     LifetimeExtendedTemporaryDecl *D) {
1164   VisitDecl(D);
1165   Record.AddDeclRef(D->getExtendingDecl());
1166   Record.AddStmt(D->getTemporaryExpr());
1167   Record.push_back(static_cast<bool>(D->getValue()));
1168   if (D->getValue())
1169     Record.AddAPValue(*D->getValue());
1170   Record.push_back(D->getManglingNumber());
1171   Code = serialization::DECL_LIFETIME_EXTENDED_TEMPORARY;
1172 }
1173 void ASTDeclWriter::VisitBlockDecl(BlockDecl *D) {
1174   VisitDecl(D);
1175   Record.AddStmt(D->getBody());
1176   Record.AddTypeSourceInfo(D->getSignatureAsWritten());
1177   Record.push_back(D->param_size());
1178   for (ParmVarDecl *P : D->parameters())
1179     Record.AddDeclRef(P);
1180   Record.push_back(D->isVariadic());
1181   Record.push_back(D->blockMissingReturnType());
1182   Record.push_back(D->isConversionFromLambda());
1183   Record.push_back(D->doesNotEscape());
1184   Record.push_back(D->canAvoidCopyToHeap());
1185   Record.push_back(D->capturesCXXThis());
1186   Record.push_back(D->getNumCaptures());
1187   for (const auto &capture : D->captures()) {
1188     Record.AddDeclRef(capture.getVariable());
1189 
1190     unsigned flags = 0;
1191     if (capture.isByRef()) flags |= 1;
1192     if (capture.isNested()) flags |= 2;
1193     if (capture.hasCopyExpr()) flags |= 4;
1194     Record.push_back(flags);
1195 
1196     if (capture.hasCopyExpr()) Record.AddStmt(capture.getCopyExpr());
1197   }
1198 
1199   Code = serialization::DECL_BLOCK;
1200 }
1201 
1202 void ASTDeclWriter::VisitCapturedDecl(CapturedDecl *CD) {
1203   Record.push_back(CD->getNumParams());
1204   VisitDecl(CD);
1205   Record.push_back(CD->getContextParamPosition());
1206   Record.push_back(CD->isNothrow() ? 1 : 0);
1207   // Body is stored by VisitCapturedStmt.
1208   for (unsigned I = 0; I < CD->getNumParams(); ++I)
1209     Record.AddDeclRef(CD->getParam(I));
1210   Code = serialization::DECL_CAPTURED;
1211 }
1212 
1213 void ASTDeclWriter::VisitLinkageSpecDecl(LinkageSpecDecl *D) {
1214   VisitDecl(D);
1215   Record.push_back(D->getLanguage());
1216   Record.AddSourceLocation(D->getExternLoc());
1217   Record.AddSourceLocation(D->getRBraceLoc());
1218   Code = serialization::DECL_LINKAGE_SPEC;
1219 }
1220 
1221 void ASTDeclWriter::VisitExportDecl(ExportDecl *D) {
1222   VisitDecl(D);
1223   Record.AddSourceLocation(D->getRBraceLoc());
1224   Code = serialization::DECL_EXPORT;
1225 }
1226 
1227 void ASTDeclWriter::VisitLabelDecl(LabelDecl *D) {
1228   VisitNamedDecl(D);
1229   Record.AddSourceLocation(D->getBeginLoc());
1230   Code = serialization::DECL_LABEL;
1231 }
1232 
1233 
1234 void ASTDeclWriter::VisitNamespaceDecl(NamespaceDecl *D) {
1235   VisitRedeclarable(D);
1236   VisitNamedDecl(D);
1237   Record.push_back(D->isInline());
1238   Record.AddSourceLocation(D->getBeginLoc());
1239   Record.AddSourceLocation(D->getRBraceLoc());
1240 
1241   if (D->isOriginalNamespace())
1242     Record.AddDeclRef(D->getAnonymousNamespace());
1243   Code = serialization::DECL_NAMESPACE;
1244 
1245   if (Writer.hasChain() && D->isAnonymousNamespace() &&
1246       D == D->getMostRecentDecl()) {
1247     // This is a most recent reopening of the anonymous namespace. If its parent
1248     // is in a previous PCH (or is the TU), mark that parent for update, because
1249     // the original namespace always points to the latest re-opening of its
1250     // anonymous namespace.
1251     Decl *Parent = cast<Decl>(
1252         D->getParent()->getRedeclContext()->getPrimaryContext());
1253     if (Parent->isFromASTFile() || isa<TranslationUnitDecl>(Parent)) {
1254       Writer.DeclUpdates[Parent].push_back(
1255           ASTWriter::DeclUpdate(UPD_CXX_ADDED_ANONYMOUS_NAMESPACE, D));
1256     }
1257   }
1258 }
1259 
1260 void ASTDeclWriter::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
1261   VisitRedeclarable(D);
1262   VisitNamedDecl(D);
1263   Record.AddSourceLocation(D->getNamespaceLoc());
1264   Record.AddSourceLocation(D->getTargetNameLoc());
1265   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1266   Record.AddDeclRef(D->getNamespace());
1267   Code = serialization::DECL_NAMESPACE_ALIAS;
1268 }
1269 
1270 void ASTDeclWriter::VisitUsingDecl(UsingDecl *D) {
1271   VisitNamedDecl(D);
1272   Record.AddSourceLocation(D->getUsingLoc());
1273   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1274   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
1275   Record.AddDeclRef(D->FirstUsingShadow.getPointer());
1276   Record.push_back(D->hasTypename());
1277   Record.AddDeclRef(Context.getInstantiatedFromUsingDecl(D));
1278   Code = serialization::DECL_USING;
1279 }
1280 
1281 void ASTDeclWriter::VisitUsingPackDecl(UsingPackDecl *D) {
1282   Record.push_back(D->NumExpansions);
1283   VisitNamedDecl(D);
1284   Record.AddDeclRef(D->getInstantiatedFromUsingDecl());
1285   for (auto *E : D->expansions())
1286     Record.AddDeclRef(E);
1287   Code = serialization::DECL_USING_PACK;
1288 }
1289 
1290 void ASTDeclWriter::VisitUsingShadowDecl(UsingShadowDecl *D) {
1291   VisitRedeclarable(D);
1292   VisitNamedDecl(D);
1293   Record.AddDeclRef(D->getTargetDecl());
1294   Record.push_back(D->getIdentifierNamespace());
1295   Record.AddDeclRef(D->UsingOrNextShadow);
1296   Record.AddDeclRef(Context.getInstantiatedFromUsingShadowDecl(D));
1297   Code = serialization::DECL_USING_SHADOW;
1298 }
1299 
1300 void ASTDeclWriter::VisitConstructorUsingShadowDecl(
1301     ConstructorUsingShadowDecl *D) {
1302   VisitUsingShadowDecl(D);
1303   Record.AddDeclRef(D->NominatedBaseClassShadowDecl);
1304   Record.AddDeclRef(D->ConstructedBaseClassShadowDecl);
1305   Record.push_back(D->IsVirtual);
1306   Code = serialization::DECL_CONSTRUCTOR_USING_SHADOW;
1307 }
1308 
1309 void ASTDeclWriter::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1310   VisitNamedDecl(D);
1311   Record.AddSourceLocation(D->getUsingLoc());
1312   Record.AddSourceLocation(D->getNamespaceKeyLocation());
1313   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1314   Record.AddDeclRef(D->getNominatedNamespace());
1315   Record.AddDeclRef(dyn_cast<Decl>(D->getCommonAncestor()));
1316   Code = serialization::DECL_USING_DIRECTIVE;
1317 }
1318 
1319 void ASTDeclWriter::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1320   VisitValueDecl(D);
1321   Record.AddSourceLocation(D->getUsingLoc());
1322   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1323   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
1324   Record.AddSourceLocation(D->getEllipsisLoc());
1325   Code = serialization::DECL_UNRESOLVED_USING_VALUE;
1326 }
1327 
1328 void ASTDeclWriter::VisitUnresolvedUsingTypenameDecl(
1329                                                UnresolvedUsingTypenameDecl *D) {
1330   VisitTypeDecl(D);
1331   Record.AddSourceLocation(D->getTypenameLoc());
1332   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1333   Record.AddSourceLocation(D->getEllipsisLoc());
1334   Code = serialization::DECL_UNRESOLVED_USING_TYPENAME;
1335 }
1336 
1337 void ASTDeclWriter::VisitUnresolvedUsingIfExistsDecl(
1338     UnresolvedUsingIfExistsDecl *D) {
1339   VisitNamedDecl(D);
1340   Code = serialization::DECL_UNRESOLVED_USING_IF_EXISTS;
1341 }
1342 
1343 void ASTDeclWriter::VisitCXXRecordDecl(CXXRecordDecl *D) {
1344   VisitRecordDecl(D);
1345 
1346   enum {
1347     CXXRecNotTemplate = 0, CXXRecTemplate, CXXRecMemberSpecialization
1348   };
1349   if (ClassTemplateDecl *TemplD = D->getDescribedClassTemplate()) {
1350     Record.push_back(CXXRecTemplate);
1351     Record.AddDeclRef(TemplD);
1352   } else if (MemberSpecializationInfo *MSInfo
1353                = D->getMemberSpecializationInfo()) {
1354     Record.push_back(CXXRecMemberSpecialization);
1355     Record.AddDeclRef(MSInfo->getInstantiatedFrom());
1356     Record.push_back(MSInfo->getTemplateSpecializationKind());
1357     Record.AddSourceLocation(MSInfo->getPointOfInstantiation());
1358   } else {
1359     Record.push_back(CXXRecNotTemplate);
1360   }
1361 
1362   Record.push_back(D->isThisDeclarationADefinition());
1363   if (D->isThisDeclarationADefinition())
1364     Record.AddCXXDefinitionData(D);
1365 
1366   // Store (what we currently believe to be) the key function to avoid
1367   // deserializing every method so we can compute it.
1368   if (D->isCompleteDefinition())
1369     Record.AddDeclRef(Context.getCurrentKeyFunction(D));
1370 
1371   Code = serialization::DECL_CXX_RECORD;
1372 }
1373 
1374 void ASTDeclWriter::VisitCXXMethodDecl(CXXMethodDecl *D) {
1375   VisitFunctionDecl(D);
1376   if (D->isCanonicalDecl()) {
1377     Record.push_back(D->size_overridden_methods());
1378     for (const CXXMethodDecl *MD : D->overridden_methods())
1379       Record.AddDeclRef(MD);
1380   } else {
1381     // We only need to record overridden methods once for the canonical decl.
1382     Record.push_back(0);
1383   }
1384 
1385   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1386       D->getFirstDecl() == D->getMostRecentDecl() &&
1387       !D->isInvalidDecl() &&
1388       !D->hasAttrs() &&
1389       !D->isTopLevelDeclInObjCContainer() &&
1390       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1391       !D->hasExtInfo() &&
1392       !D->hasInheritedPrototype() &&
1393       D->hasWrittenPrototype())
1394     AbbrevToUse = Writer.getDeclCXXMethodAbbrev();
1395 
1396   Code = serialization::DECL_CXX_METHOD;
1397 }
1398 
1399 void ASTDeclWriter::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1400   Record.push_back(D->getTrailingAllocKind());
1401   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
1402   if (auto Inherited = D->getInheritedConstructor()) {
1403     Record.AddDeclRef(Inherited.getShadowDecl());
1404     Record.AddDeclRef(Inherited.getConstructor());
1405   }
1406 
1407   VisitCXXMethodDecl(D);
1408   Code = serialization::DECL_CXX_CONSTRUCTOR;
1409 }
1410 
1411 void ASTDeclWriter::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1412   VisitCXXMethodDecl(D);
1413 
1414   Record.AddDeclRef(D->getOperatorDelete());
1415   if (D->getOperatorDelete())
1416     Record.AddStmt(D->getOperatorDeleteThisArg());
1417 
1418   Code = serialization::DECL_CXX_DESTRUCTOR;
1419 }
1420 
1421 void ASTDeclWriter::VisitCXXConversionDecl(CXXConversionDecl *D) {
1422   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
1423   VisitCXXMethodDecl(D);
1424   Code = serialization::DECL_CXX_CONVERSION;
1425 }
1426 
1427 void ASTDeclWriter::VisitImportDecl(ImportDecl *D) {
1428   VisitDecl(D);
1429   Record.push_back(Writer.getSubmoduleID(D->getImportedModule()));
1430   ArrayRef<SourceLocation> IdentifierLocs = D->getIdentifierLocs();
1431   Record.push_back(!IdentifierLocs.empty());
1432   if (IdentifierLocs.empty()) {
1433     Record.AddSourceLocation(D->getEndLoc());
1434     Record.push_back(1);
1435   } else {
1436     for (unsigned I = 0, N = IdentifierLocs.size(); I != N; ++I)
1437       Record.AddSourceLocation(IdentifierLocs[I]);
1438     Record.push_back(IdentifierLocs.size());
1439   }
1440   // Note: the number of source locations must always be the last element in
1441   // the record.
1442   Code = serialization::DECL_IMPORT;
1443 }
1444 
1445 void ASTDeclWriter::VisitAccessSpecDecl(AccessSpecDecl *D) {
1446   VisitDecl(D);
1447   Record.AddSourceLocation(D->getColonLoc());
1448   Code = serialization::DECL_ACCESS_SPEC;
1449 }
1450 
1451 void ASTDeclWriter::VisitFriendDecl(FriendDecl *D) {
1452   // Record the number of friend type template parameter lists here
1453   // so as to simplify memory allocation during deserialization.
1454   Record.push_back(D->NumTPLists);
1455   VisitDecl(D);
1456   bool hasFriendDecl = D->Friend.is<NamedDecl*>();
1457   Record.push_back(hasFriendDecl);
1458   if (hasFriendDecl)
1459     Record.AddDeclRef(D->getFriendDecl());
1460   else
1461     Record.AddTypeSourceInfo(D->getFriendType());
1462   for (unsigned i = 0; i < D->NumTPLists; ++i)
1463     Record.AddTemplateParameterList(D->getFriendTypeTemplateParameterList(i));
1464   Record.AddDeclRef(D->getNextFriend());
1465   Record.push_back(D->UnsupportedFriend);
1466   Record.AddSourceLocation(D->FriendLoc);
1467   Code = serialization::DECL_FRIEND;
1468 }
1469 
1470 void ASTDeclWriter::VisitFriendTemplateDecl(FriendTemplateDecl *D) {
1471   VisitDecl(D);
1472   Record.push_back(D->getNumTemplateParameters());
1473   for (unsigned i = 0, e = D->getNumTemplateParameters(); i != e; ++i)
1474     Record.AddTemplateParameterList(D->getTemplateParameterList(i));
1475   Record.push_back(D->getFriendDecl() != nullptr);
1476   if (D->getFriendDecl())
1477     Record.AddDeclRef(D->getFriendDecl());
1478   else
1479     Record.AddTypeSourceInfo(D->getFriendType());
1480   Record.AddSourceLocation(D->getFriendLoc());
1481   Code = serialization::DECL_FRIEND_TEMPLATE;
1482 }
1483 
1484 void ASTDeclWriter::VisitTemplateDecl(TemplateDecl *D) {
1485   VisitNamedDecl(D);
1486 
1487   Record.AddDeclRef(D->getTemplatedDecl());
1488   Record.AddTemplateParameterList(D->getTemplateParameters());
1489 }
1490 
1491 void ASTDeclWriter::VisitConceptDecl(ConceptDecl *D) {
1492   VisitTemplateDecl(D);
1493   Record.AddStmt(D->getConstraintExpr());
1494   Code = serialization::DECL_CONCEPT;
1495 }
1496 
1497 void ASTDeclWriter::VisitRequiresExprBodyDecl(RequiresExprBodyDecl *D) {
1498   Code = serialization::DECL_REQUIRES_EXPR_BODY;
1499 }
1500 
1501 void ASTDeclWriter::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
1502   VisitRedeclarable(D);
1503 
1504   // Emit data to initialize CommonOrPrev before VisitTemplateDecl so that
1505   // getCommonPtr() can be used while this is still initializing.
1506   if (D->isFirstDecl()) {
1507     // This declaration owns the 'common' pointer, so serialize that data now.
1508     Record.AddDeclRef(D->getInstantiatedFromMemberTemplate());
1509     if (D->getInstantiatedFromMemberTemplate())
1510       Record.push_back(D->isMemberSpecialization());
1511   }
1512 
1513   VisitTemplateDecl(D);
1514   Record.push_back(D->getIdentifierNamespace());
1515 }
1516 
1517 void ASTDeclWriter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
1518   VisitRedeclarableTemplateDecl(D);
1519 
1520   if (D->isFirstDecl())
1521     AddTemplateSpecializations(D);
1522   Code = serialization::DECL_CLASS_TEMPLATE;
1523 }
1524 
1525 void ASTDeclWriter::VisitClassTemplateSpecializationDecl(
1526                                            ClassTemplateSpecializationDecl *D) {
1527   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1528 
1529   VisitCXXRecordDecl(D);
1530 
1531   llvm::PointerUnion<ClassTemplateDecl *,
1532                      ClassTemplatePartialSpecializationDecl *> InstFrom
1533     = D->getSpecializedTemplateOrPartial();
1534   if (Decl *InstFromD = InstFrom.dyn_cast<ClassTemplateDecl *>()) {
1535     Record.AddDeclRef(InstFromD);
1536   } else {
1537     Record.AddDeclRef(InstFrom.get<ClassTemplatePartialSpecializationDecl *>());
1538     Record.AddTemplateArgumentList(&D->getTemplateInstantiationArgs());
1539   }
1540 
1541   Record.AddTemplateArgumentList(&D->getTemplateArgs());
1542   Record.AddSourceLocation(D->getPointOfInstantiation());
1543   Record.push_back(D->getSpecializationKind());
1544   Record.push_back(D->isCanonicalDecl());
1545 
1546   if (D->isCanonicalDecl()) {
1547     // When reading, we'll add it to the folding set of the following template.
1548     Record.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl());
1549   }
1550 
1551   // Explicit info.
1552   Record.AddTypeSourceInfo(D->getTypeAsWritten());
1553   if (D->getTypeAsWritten()) {
1554     Record.AddSourceLocation(D->getExternLoc());
1555     Record.AddSourceLocation(D->getTemplateKeywordLoc());
1556   }
1557 
1558   Code = serialization::DECL_CLASS_TEMPLATE_SPECIALIZATION;
1559 }
1560 
1561 void ASTDeclWriter::VisitClassTemplatePartialSpecializationDecl(
1562                                     ClassTemplatePartialSpecializationDecl *D) {
1563   Record.AddTemplateParameterList(D->getTemplateParameters());
1564   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1565 
1566   VisitClassTemplateSpecializationDecl(D);
1567 
1568   // These are read/set from/to the first declaration.
1569   if (D->getPreviousDecl() == nullptr) {
1570     Record.AddDeclRef(D->getInstantiatedFromMember());
1571     Record.push_back(D->isMemberSpecialization());
1572   }
1573 
1574   Code = serialization::DECL_CLASS_TEMPLATE_PARTIAL_SPECIALIZATION;
1575 }
1576 
1577 void ASTDeclWriter::VisitVarTemplateDecl(VarTemplateDecl *D) {
1578   VisitRedeclarableTemplateDecl(D);
1579 
1580   if (D->isFirstDecl())
1581     AddTemplateSpecializations(D);
1582   Code = serialization::DECL_VAR_TEMPLATE;
1583 }
1584 
1585 void ASTDeclWriter::VisitVarTemplateSpecializationDecl(
1586     VarTemplateSpecializationDecl *D) {
1587   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1588 
1589   VisitVarDecl(D);
1590 
1591   llvm::PointerUnion<VarTemplateDecl *, VarTemplatePartialSpecializationDecl *>
1592   InstFrom = D->getSpecializedTemplateOrPartial();
1593   if (Decl *InstFromD = InstFrom.dyn_cast<VarTemplateDecl *>()) {
1594     Record.AddDeclRef(InstFromD);
1595   } else {
1596     Record.AddDeclRef(InstFrom.get<VarTemplatePartialSpecializationDecl *>());
1597     Record.AddTemplateArgumentList(&D->getTemplateInstantiationArgs());
1598   }
1599 
1600   // Explicit info.
1601   Record.AddTypeSourceInfo(D->getTypeAsWritten());
1602   if (D->getTypeAsWritten()) {
1603     Record.AddSourceLocation(D->getExternLoc());
1604     Record.AddSourceLocation(D->getTemplateKeywordLoc());
1605   }
1606 
1607   Record.AddTemplateArgumentList(&D->getTemplateArgs());
1608   Record.AddSourceLocation(D->getPointOfInstantiation());
1609   Record.push_back(D->getSpecializationKind());
1610   Record.push_back(D->IsCompleteDefinition);
1611   Record.push_back(D->isCanonicalDecl());
1612 
1613   if (D->isCanonicalDecl()) {
1614     // When reading, we'll add it to the folding set of the following template.
1615     Record.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl());
1616   }
1617 
1618   Code = serialization::DECL_VAR_TEMPLATE_SPECIALIZATION;
1619 }
1620 
1621 void ASTDeclWriter::VisitVarTemplatePartialSpecializationDecl(
1622     VarTemplatePartialSpecializationDecl *D) {
1623   Record.AddTemplateParameterList(D->getTemplateParameters());
1624   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1625 
1626   VisitVarTemplateSpecializationDecl(D);
1627 
1628   // These are read/set from/to the first declaration.
1629   if (D->getPreviousDecl() == nullptr) {
1630     Record.AddDeclRef(D->getInstantiatedFromMember());
1631     Record.push_back(D->isMemberSpecialization());
1632   }
1633 
1634   Code = serialization::DECL_VAR_TEMPLATE_PARTIAL_SPECIALIZATION;
1635 }
1636 
1637 void ASTDeclWriter::VisitClassScopeFunctionSpecializationDecl(
1638                                     ClassScopeFunctionSpecializationDecl *D) {
1639   VisitDecl(D);
1640   Record.AddDeclRef(D->getSpecialization());
1641   Record.push_back(D->hasExplicitTemplateArgs());
1642   if (D->hasExplicitTemplateArgs())
1643     Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1644   Code = serialization::DECL_CLASS_SCOPE_FUNCTION_SPECIALIZATION;
1645 }
1646 
1647 
1648 void ASTDeclWriter::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
1649   VisitRedeclarableTemplateDecl(D);
1650 
1651   if (D->isFirstDecl())
1652     AddTemplateSpecializations(D);
1653   Code = serialization::DECL_FUNCTION_TEMPLATE;
1654 }
1655 
1656 void ASTDeclWriter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
1657   Record.push_back(D->hasTypeConstraint());
1658   VisitTypeDecl(D);
1659 
1660   Record.push_back(D->wasDeclaredWithTypename());
1661 
1662   const TypeConstraint *TC = D->getTypeConstraint();
1663   Record.push_back(TC != nullptr);
1664   if (TC) {
1665     Record.AddNestedNameSpecifierLoc(TC->getNestedNameSpecifierLoc());
1666     Record.AddDeclarationNameInfo(TC->getConceptNameInfo());
1667     Record.AddDeclRef(TC->getNamedConcept());
1668     Record.push_back(TC->getTemplateArgsAsWritten() != nullptr);
1669     if (TC->getTemplateArgsAsWritten())
1670       Record.AddASTTemplateArgumentListInfo(TC->getTemplateArgsAsWritten());
1671     Record.AddStmt(TC->getImmediatelyDeclaredConstraint());
1672     Record.push_back(D->isExpandedParameterPack());
1673     if (D->isExpandedParameterPack())
1674       Record.push_back(D->getNumExpansionParameters());
1675   }
1676 
1677   bool OwnsDefaultArg = D->hasDefaultArgument() &&
1678                         !D->defaultArgumentWasInherited();
1679   Record.push_back(OwnsDefaultArg);
1680   if (OwnsDefaultArg)
1681     Record.AddTypeSourceInfo(D->getDefaultArgumentInfo());
1682 
1683   Code = serialization::DECL_TEMPLATE_TYPE_PARM;
1684 }
1685 
1686 void ASTDeclWriter::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
1687   // For an expanded parameter pack, record the number of expansion types here
1688   // so that it's easier for deserialization to allocate the right amount of
1689   // memory.
1690   Expr *TypeConstraint = D->getPlaceholderTypeConstraint();
1691   Record.push_back(!!TypeConstraint);
1692   if (D->isExpandedParameterPack())
1693     Record.push_back(D->getNumExpansionTypes());
1694 
1695   VisitDeclaratorDecl(D);
1696   // TemplateParmPosition.
1697   Record.push_back(D->getDepth());
1698   Record.push_back(D->getPosition());
1699   if (TypeConstraint)
1700     Record.AddStmt(TypeConstraint);
1701 
1702   if (D->isExpandedParameterPack()) {
1703     for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1704       Record.AddTypeRef(D->getExpansionType(I));
1705       Record.AddTypeSourceInfo(D->getExpansionTypeSourceInfo(I));
1706     }
1707 
1708     Code = serialization::DECL_EXPANDED_NON_TYPE_TEMPLATE_PARM_PACK;
1709   } else {
1710     // Rest of NonTypeTemplateParmDecl.
1711     Record.push_back(D->isParameterPack());
1712     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1713                           !D->defaultArgumentWasInherited();
1714     Record.push_back(OwnsDefaultArg);
1715     if (OwnsDefaultArg)
1716       Record.AddStmt(D->getDefaultArgument());
1717     Code = serialization::DECL_NON_TYPE_TEMPLATE_PARM;
1718   }
1719 }
1720 
1721 void ASTDeclWriter::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
1722   // For an expanded parameter pack, record the number of expansion types here
1723   // so that it's easier for deserialization to allocate the right amount of
1724   // memory.
1725   if (D->isExpandedParameterPack())
1726     Record.push_back(D->getNumExpansionTemplateParameters());
1727 
1728   VisitTemplateDecl(D);
1729   // TemplateParmPosition.
1730   Record.push_back(D->getDepth());
1731   Record.push_back(D->getPosition());
1732 
1733   if (D->isExpandedParameterPack()) {
1734     for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
1735          I != N; ++I)
1736       Record.AddTemplateParameterList(D->getExpansionTemplateParameters(I));
1737     Code = serialization::DECL_EXPANDED_TEMPLATE_TEMPLATE_PARM_PACK;
1738   } else {
1739     // Rest of TemplateTemplateParmDecl.
1740     Record.push_back(D->isParameterPack());
1741     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1742                           !D->defaultArgumentWasInherited();
1743     Record.push_back(OwnsDefaultArg);
1744     if (OwnsDefaultArg)
1745       Record.AddTemplateArgumentLoc(D->getDefaultArgument());
1746     Code = serialization::DECL_TEMPLATE_TEMPLATE_PARM;
1747   }
1748 }
1749 
1750 void ASTDeclWriter::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
1751   VisitRedeclarableTemplateDecl(D);
1752   Code = serialization::DECL_TYPE_ALIAS_TEMPLATE;
1753 }
1754 
1755 void ASTDeclWriter::VisitStaticAssertDecl(StaticAssertDecl *D) {
1756   VisitDecl(D);
1757   Record.AddStmt(D->getAssertExpr());
1758   Record.push_back(D->isFailed());
1759   Record.AddStmt(D->getMessage());
1760   Record.AddSourceLocation(D->getRParenLoc());
1761   Code = serialization::DECL_STATIC_ASSERT;
1762 }
1763 
1764 /// Emit the DeclContext part of a declaration context decl.
1765 void ASTDeclWriter::VisitDeclContext(DeclContext *DC) {
1766   Record.AddOffset(Writer.WriteDeclContextLexicalBlock(Context, DC));
1767   Record.AddOffset(Writer.WriteDeclContextVisibleBlock(Context, DC));
1768 }
1769 
1770 const Decl *ASTWriter::getFirstLocalDecl(const Decl *D) {
1771   assert(IsLocalDecl(D) && "expected a local declaration");
1772 
1773   const Decl *Canon = D->getCanonicalDecl();
1774   if (IsLocalDecl(Canon))
1775     return Canon;
1776 
1777   const Decl *&CacheEntry = FirstLocalDeclCache[Canon];
1778   if (CacheEntry)
1779     return CacheEntry;
1780 
1781   for (const Decl *Redecl = D; Redecl; Redecl = Redecl->getPreviousDecl())
1782     if (IsLocalDecl(Redecl))
1783       D = Redecl;
1784   return CacheEntry = D;
1785 }
1786 
1787 template <typename T>
1788 void ASTDeclWriter::VisitRedeclarable(Redeclarable<T> *D) {
1789   T *First = D->getFirstDecl();
1790   T *MostRecent = First->getMostRecentDecl();
1791   T *DAsT = static_cast<T *>(D);
1792   if (MostRecent != First) {
1793     assert(isRedeclarableDeclKind(DAsT->getKind()) &&
1794            "Not considered redeclarable?");
1795 
1796     Record.AddDeclRef(First);
1797 
1798     // Write out a list of local redeclarations of this declaration if it's the
1799     // first local declaration in the chain.
1800     const Decl *FirstLocal = Writer.getFirstLocalDecl(DAsT);
1801     if (DAsT == FirstLocal) {
1802       // Emit a list of all imported first declarations so that we can be sure
1803       // that all redeclarations visible to this module are before D in the
1804       // redecl chain.
1805       unsigned I = Record.size();
1806       Record.push_back(0);
1807       if (Writer.Chain)
1808         AddFirstDeclFromEachModule(DAsT, /*IncludeLocal*/false);
1809       // This is the number of imported first declarations + 1.
1810       Record[I] = Record.size() - I;
1811 
1812       // Collect the set of local redeclarations of this declaration, from
1813       // newest to oldest.
1814       ASTWriter::RecordData LocalRedecls;
1815       ASTRecordWriter LocalRedeclWriter(Record, LocalRedecls);
1816       for (const Decl *Prev = FirstLocal->getMostRecentDecl();
1817            Prev != FirstLocal; Prev = Prev->getPreviousDecl())
1818         if (!Prev->isFromASTFile())
1819           LocalRedeclWriter.AddDeclRef(Prev);
1820 
1821       // If we have any redecls, write them now as a separate record preceding
1822       // the declaration itself.
1823       if (LocalRedecls.empty())
1824         Record.push_back(0);
1825       else
1826         Record.AddOffset(LocalRedeclWriter.Emit(LOCAL_REDECLARATIONS));
1827     } else {
1828       Record.push_back(0);
1829       Record.AddDeclRef(FirstLocal);
1830     }
1831 
1832     // Make sure that we serialize both the previous and the most-recent
1833     // declarations, which (transitively) ensures that all declarations in the
1834     // chain get serialized.
1835     //
1836     // FIXME: This is not correct; when we reach an imported declaration we
1837     // won't emit its previous declaration.
1838     (void)Writer.GetDeclRef(D->getPreviousDecl());
1839     (void)Writer.GetDeclRef(MostRecent);
1840   } else {
1841     // We use the sentinel value 0 to indicate an only declaration.
1842     Record.push_back(0);
1843   }
1844 }
1845 
1846 void ASTDeclWriter::VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D) {
1847   Record.writeOMPChildren(D->Data);
1848   VisitDecl(D);
1849   Code = serialization::DECL_OMP_THREADPRIVATE;
1850 }
1851 
1852 void ASTDeclWriter::VisitOMPAllocateDecl(OMPAllocateDecl *D) {
1853   Record.writeOMPChildren(D->Data);
1854   VisitDecl(D);
1855   Code = serialization::DECL_OMP_ALLOCATE;
1856 }
1857 
1858 void ASTDeclWriter::VisitOMPRequiresDecl(OMPRequiresDecl *D) {
1859   Record.writeOMPChildren(D->Data);
1860   VisitDecl(D);
1861   Code = serialization::DECL_OMP_REQUIRES;
1862 }
1863 
1864 void ASTDeclWriter::VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D) {
1865   VisitValueDecl(D);
1866   Record.AddSourceLocation(D->getBeginLoc());
1867   Record.AddStmt(D->getCombinerIn());
1868   Record.AddStmt(D->getCombinerOut());
1869   Record.AddStmt(D->getCombiner());
1870   Record.AddStmt(D->getInitOrig());
1871   Record.AddStmt(D->getInitPriv());
1872   Record.AddStmt(D->getInitializer());
1873   Record.push_back(D->getInitializerKind());
1874   Record.AddDeclRef(D->getPrevDeclInScope());
1875   Code = serialization::DECL_OMP_DECLARE_REDUCTION;
1876 }
1877 
1878 void ASTDeclWriter::VisitOMPDeclareMapperDecl(OMPDeclareMapperDecl *D) {
1879   Record.writeOMPChildren(D->Data);
1880   VisitValueDecl(D);
1881   Record.AddDeclarationName(D->getVarName());
1882   Record.AddDeclRef(D->getPrevDeclInScope());
1883   Code = serialization::DECL_OMP_DECLARE_MAPPER;
1884 }
1885 
1886 void ASTDeclWriter::VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D) {
1887   VisitVarDecl(D);
1888   Code = serialization::DECL_OMP_CAPTUREDEXPR;
1889 }
1890 
1891 //===----------------------------------------------------------------------===//
1892 // ASTWriter Implementation
1893 //===----------------------------------------------------------------------===//
1894 
1895 void ASTWriter::WriteDeclAbbrevs() {
1896   using namespace llvm;
1897 
1898   std::shared_ptr<BitCodeAbbrev> Abv;
1899 
1900   // Abbreviation for DECL_FIELD
1901   Abv = std::make_shared<BitCodeAbbrev>();
1902   Abv->Add(BitCodeAbbrevOp(serialization::DECL_FIELD));
1903   // Decl
1904   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1905   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1906   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1907   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1908   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1909   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1910   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1911   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1912   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1913   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1914   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1915   // NamedDecl
1916   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1917   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1918   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1919   // ValueDecl
1920   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1921   // DeclaratorDecl
1922   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1923   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1924   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
1925   // FieldDecl
1926   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1927   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
1928   // Type Source Info
1929   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1930   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1931   DeclFieldAbbrev = Stream.EmitAbbrev(std::move(Abv));
1932 
1933   // Abbreviation for DECL_OBJC_IVAR
1934   Abv = std::make_shared<BitCodeAbbrev>();
1935   Abv->Add(BitCodeAbbrevOp(serialization::DECL_OBJC_IVAR));
1936   // Decl
1937   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1938   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1939   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1940   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1941   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1942   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1943   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1944   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1945   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1946   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1947   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1948   // NamedDecl
1949   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1950   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1951   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1952   // ValueDecl
1953   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1954   // DeclaratorDecl
1955   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1956   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1957   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
1958   // FieldDecl
1959   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1960   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
1961   // ObjC Ivar
1962   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getAccessControl
1963   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getSynthesize
1964   // Type Source Info
1965   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1966   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1967   DeclObjCIvarAbbrev = Stream.EmitAbbrev(std::move(Abv));
1968 
1969   // Abbreviation for DECL_ENUM
1970   Abv = std::make_shared<BitCodeAbbrev>();
1971   Abv->Add(BitCodeAbbrevOp(serialization::DECL_ENUM));
1972   // Redeclarable
1973   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1974   // Decl
1975   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1976   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1977   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1978   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1979   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1980   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1981   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1982   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1983   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1984   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1985   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1986   // NamedDecl
1987   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1988   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1989   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1990   // TypeDecl
1991   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1992   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1993   // TagDecl
1994   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
1995   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
1996   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
1997   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
1998   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
1999   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
2000   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2001   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2002   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
2003   // EnumDecl
2004   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddTypeRef
2005   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IntegerType
2006   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getPromotionType
2007   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumPositiveBits
2008   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumNegativeBits
2009   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScoped
2010   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScopedUsingClassTag
2011   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isFixed
2012   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));// ODRHash
2013   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InstantiatedMembEnum
2014   // DC
2015   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
2016   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
2017   DeclEnumAbbrev = Stream.EmitAbbrev(std::move(Abv));
2018 
2019   // Abbreviation for DECL_RECORD
2020   Abv = std::make_shared<BitCodeAbbrev>();
2021   Abv->Add(BitCodeAbbrevOp(serialization::DECL_RECORD));
2022   // Redeclarable
2023   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2024   // Decl
2025   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2026   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2027   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2028   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2029   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2030   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2031   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2032   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2033   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2034   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2035   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2036   // NamedDecl
2037   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2038   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2039   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2040   // TypeDecl
2041   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
2042   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
2043   // TagDecl
2044   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
2045   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
2046   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
2047   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
2048   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
2049   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
2050   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2051   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2052   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
2053   // RecordDecl
2054   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // FlexibleArrayMember
2055   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // AnonymousStructUnion
2056   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasObjectMember
2057   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasVolatileMember
2058 
2059   // isNonTrivialToPrimitiveDefaultInitialize
2060   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2061   // isNonTrivialToPrimitiveCopy
2062   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2063   // isNonTrivialToPrimitiveDestroy
2064   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2065   // hasNonTrivialToPrimitiveDefaultInitializeCUnion
2066   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2067   // hasNonTrivialToPrimitiveDestructCUnion
2068   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2069   // hasNonTrivialToPrimitiveCopyCUnion
2070   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2071   // isParamDestroyedInCallee
2072   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2073   // getArgPassingRestrictions
2074   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));
2075 
2076   // DC
2077   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
2078   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
2079   DeclRecordAbbrev = Stream.EmitAbbrev(std::move(Abv));
2080 
2081   // Abbreviation for DECL_PARM_VAR
2082   Abv = std::make_shared<BitCodeAbbrev>();
2083   Abv->Add(BitCodeAbbrevOp(serialization::DECL_PARM_VAR));
2084   // Redeclarable
2085   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2086   // Decl
2087   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2088   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2089   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2090   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2091   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2092   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2093   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2094   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2095   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2096   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2097   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2098   // NamedDecl
2099   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2100   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2101   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2102   // ValueDecl
2103   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2104   // DeclaratorDecl
2105   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
2106   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
2107   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
2108   // VarDecl
2109   Abv->Add(BitCodeAbbrevOp(0));                       // SClass
2110   Abv->Add(BitCodeAbbrevOp(0));                       // TSCSpec
2111   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
2112   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isARCPseudoStrong
2113   Abv->Add(BitCodeAbbrevOp(0));                       // Linkage
2114   Abv->Add(BitCodeAbbrevOp(0));                       // HasInit
2115   Abv->Add(BitCodeAbbrevOp(0));                   // HasMemberSpecializationInfo
2116   // ParmVarDecl
2117   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsObjCMethodParameter
2118   Abv->Add(BitCodeAbbrevOp(0));                       // ScopeDepth
2119   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ScopeIndex
2120   Abv->Add(BitCodeAbbrevOp(0));                       // ObjCDeclQualifier
2121   Abv->Add(BitCodeAbbrevOp(0));                       // KNRPromoted
2122   Abv->Add(BitCodeAbbrevOp(0));                       // HasInheritedDefaultArg
2123   Abv->Add(BitCodeAbbrevOp(0));                   // HasUninstantiatedDefaultArg
2124   // Type Source Info
2125   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2126   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2127   DeclParmVarAbbrev = Stream.EmitAbbrev(std::move(Abv));
2128 
2129   // Abbreviation for DECL_TYPEDEF
2130   Abv = std::make_shared<BitCodeAbbrev>();
2131   Abv->Add(BitCodeAbbrevOp(serialization::DECL_TYPEDEF));
2132   // Redeclarable
2133   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2134   // Decl
2135   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2136   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2137   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2138   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2139   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2140   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isUsed
2141   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isReferenced
2142   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2143   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // C++ AccessSpecifier
2144   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2145   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2146   // NamedDecl
2147   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2148   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2149   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2150   // TypeDecl
2151   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
2152   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
2153   // TypedefDecl
2154   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2155   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2156   DeclTypedefAbbrev = Stream.EmitAbbrev(std::move(Abv));
2157 
2158   // Abbreviation for DECL_VAR
2159   Abv = std::make_shared<BitCodeAbbrev>();
2160   Abv->Add(BitCodeAbbrevOp(serialization::DECL_VAR));
2161   // Redeclarable
2162   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2163   // Decl
2164   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2165   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2166   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2167   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2168   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2169   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2170   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2171   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2172   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2173   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2174   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2175   // NamedDecl
2176   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2177   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2178   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2179   // ValueDecl
2180   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2181   // DeclaratorDecl
2182   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
2183   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
2184   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
2185   // VarDecl
2186   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // SClass
2187   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // TSCSpec
2188   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // InitStyle
2189   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isARCPseudoStrong
2190   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsThisDeclarationADemotedDefinition
2191   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isExceptionVariable
2192   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isNRVOVariable
2193   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCXXForRangeDecl
2194   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isObjCForDecl
2195   Abv->Add(BitCodeAbbrevOp(0));                         // isInline
2196   Abv->Add(BitCodeAbbrevOp(0));                         // isInlineSpecified
2197   Abv->Add(BitCodeAbbrevOp(0));                         // isConstexpr
2198   Abv->Add(BitCodeAbbrevOp(0));                         // isInitCapture
2199   Abv->Add(BitCodeAbbrevOp(0));                         // isPrevDeclInSameScope
2200   Abv->Add(BitCodeAbbrevOp(0));                         // ImplicitParamKind
2201   Abv->Add(BitCodeAbbrevOp(0));                         // EscapingByref
2202   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
2203   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // HasConstant*
2204   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // VarKind (local enum)
2205   // Type Source Info
2206   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2207   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2208   DeclVarAbbrev = Stream.EmitAbbrev(std::move(Abv));
2209 
2210   // Abbreviation for DECL_CXX_METHOD
2211   Abv = std::make_shared<BitCodeAbbrev>();
2212   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CXX_METHOD));
2213   // RedeclarableDecl
2214   Abv->Add(BitCodeAbbrevOp(0));                         // CanonicalDecl
2215   // Decl
2216   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // DeclContext
2217   Abv->Add(BitCodeAbbrevOp(0));                         // LexicalDeclContext
2218   Abv->Add(BitCodeAbbrevOp(0));                         // Invalid
2219   Abv->Add(BitCodeAbbrevOp(0));                         // HasAttrs
2220   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Implicit
2221   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Used
2222   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Referenced
2223   Abv->Add(BitCodeAbbrevOp(0));                         // InObjCContainer
2224   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // Access
2225   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ModulePrivate
2226   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SubmoduleID
2227   // NamedDecl
2228   Abv->Add(BitCodeAbbrevOp(DeclarationName::Identifier)); // NameKind
2229   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Identifier
2230   Abv->Add(BitCodeAbbrevOp(0));                         // AnonDeclNumber
2231   // ValueDecl
2232   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Type
2233   // DeclaratorDecl
2234   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InnerLocStart
2235   Abv->Add(BitCodeAbbrevOp(0));                         // HasExtInfo
2236   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // TSIType
2237   // FunctionDecl
2238   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 11)); // IDNS
2239   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // StorageClass
2240   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Inline
2241   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // InlineSpecified
2242   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // VirtualAsWritten
2243   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Pure
2244   Abv->Add(BitCodeAbbrevOp(0));                         // HasInheritedProto
2245   Abv->Add(BitCodeAbbrevOp(1));                         // HasWrittenProto
2246   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Deleted
2247   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Trivial
2248   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // TrivialForCall
2249   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Defaulted
2250   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ExplicitlyDefaulted
2251   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ImplicitReturnZero
2252   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Constexpr
2253   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // UsesSEHTry
2254   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // SkippedBody
2255   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // MultiVersion
2256   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // LateParsed
2257   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
2258   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LocEnd
2259   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32)); // ODRHash
2260   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // TemplateKind
2261   // This Array slurps the rest of the record. Fortunately we want to encode
2262   // (nearly) all the remaining (variable number of) fields in the same way.
2263   //
2264   // This is the function template information if any, then
2265   //         NumParams and Params[] from FunctionDecl, and
2266   //         NumOverriddenMethods, OverriddenMethods[] from CXXMethodDecl.
2267   //
2268   //  Add an AbbrevOp for 'size then elements' and use it here.
2269   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2270   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2271   DeclCXXMethodAbbrev = Stream.EmitAbbrev(std::move(Abv));
2272 
2273   // Abbreviation for EXPR_DECL_REF
2274   Abv = std::make_shared<BitCodeAbbrev>();
2275   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_DECL_REF));
2276   //Stmt
2277   // Expr
2278   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2279   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2280   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2281   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2282   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2283   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ContainsErrors
2284   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2285   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2286   //DeclRefExpr
2287   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HasQualifier
2288   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //GetDeclFound
2289   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ExplicitTemplateArgs
2290   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HadMultipleCandidates
2291   Abv->Add(BitCodeAbbrevOp(0)); // RefersToEnclosingVariableOrCapture
2292   Abv->Add(BitCodeAbbrevOp(0)); // NonOdrUseReason
2293   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclRef
2294   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2295   DeclRefExprAbbrev = Stream.EmitAbbrev(std::move(Abv));
2296 
2297   // Abbreviation for EXPR_INTEGER_LITERAL
2298   Abv = std::make_shared<BitCodeAbbrev>();
2299   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_INTEGER_LITERAL));
2300   //Stmt
2301   // Expr
2302   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2303   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2304   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2305   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2306   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2307   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ContainsErrors
2308   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2309   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2310   //Integer Literal
2311   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2312   Abv->Add(BitCodeAbbrevOp(32));                      // Bit Width
2313   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Value
2314   IntegerLiteralAbbrev = Stream.EmitAbbrev(std::move(Abv));
2315 
2316   // Abbreviation for EXPR_CHARACTER_LITERAL
2317   Abv = std::make_shared<BitCodeAbbrev>();
2318   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_CHARACTER_LITERAL));
2319   //Stmt
2320   // Expr
2321   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2322   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2323   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2324   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2325   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2326   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ContainsErrors
2327   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2328   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2329   //Character Literal
2330   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getValue
2331   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2332   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // getKind
2333   CharacterLiteralAbbrev = Stream.EmitAbbrev(std::move(Abv));
2334 
2335   // Abbreviation for EXPR_IMPLICIT_CAST
2336   Abv = std::make_shared<BitCodeAbbrev>();
2337   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_IMPLICIT_CAST));
2338   // Stmt
2339   // Expr
2340   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2341   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2342   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2343   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2344   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2345   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ContainsErrors
2346   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2347   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2348   // CastExpr
2349   Abv->Add(BitCodeAbbrevOp(0)); // PathSize
2350   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // HasFPFeatures
2351   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 6)); // CastKind
2352   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // PartOfExplicitCast
2353   // ImplicitCastExpr
2354   ExprImplicitCastAbbrev = Stream.EmitAbbrev(std::move(Abv));
2355 
2356   Abv = std::make_shared<BitCodeAbbrev>();
2357   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_LEXICAL));
2358   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2359   DeclContextLexicalAbbrev = Stream.EmitAbbrev(std::move(Abv));
2360 
2361   Abv = std::make_shared<BitCodeAbbrev>();
2362   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_VISIBLE));
2363   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2364   DeclContextVisibleLookupAbbrev = Stream.EmitAbbrev(std::move(Abv));
2365 }
2366 
2367 /// isRequiredDecl - Check if this is a "required" Decl, which must be seen by
2368 /// consumers of the AST.
2369 ///
2370 /// Such decls will always be deserialized from the AST file, so we would like
2371 /// this to be as restrictive as possible. Currently the predicate is driven by
2372 /// code generation requirements, if other clients have a different notion of
2373 /// what is "required" then we may have to consider an alternate scheme where
2374 /// clients can iterate over the top-level decls and get information on them,
2375 /// without necessary deserializing them. We could explicitly require such
2376 /// clients to use a separate API call to "realize" the decl. This should be
2377 /// relatively painless since they would presumably only do it for top-level
2378 /// decls.
2379 static bool isRequiredDecl(const Decl *D, ASTContext &Context,
2380                            bool WritingModule) {
2381   // An ObjCMethodDecl is never considered as "required" because its
2382   // implementation container always is.
2383 
2384   // File scoped assembly or obj-c or OMP declare target implementation must be
2385   // seen.
2386   if (isa<FileScopeAsmDecl>(D) || isa<ObjCImplDecl>(D))
2387     return true;
2388 
2389   if (WritingModule && isPartOfPerModuleInitializer(D)) {
2390     // These declarations are part of the module initializer, and are emitted
2391     // if and when the module is imported, rather than being emitted eagerly.
2392     return false;
2393   }
2394 
2395   return Context.DeclMustBeEmitted(D);
2396 }
2397 
2398 void ASTWriter::WriteDecl(ASTContext &Context, Decl *D) {
2399   PrettyDeclStackTraceEntry CrashInfo(Context, D, SourceLocation(),
2400                                       "serializing");
2401 
2402   // Determine the ID for this declaration.
2403   serialization::DeclID ID;
2404   assert(!D->isFromASTFile() && "should not be emitting imported decl");
2405   serialization::DeclID &IDR = DeclIDs[D];
2406   if (IDR == 0)
2407     IDR = NextDeclID++;
2408 
2409   ID = IDR;
2410 
2411   assert(ID >= FirstDeclID && "invalid decl ID");
2412 
2413   RecordData Record;
2414   ASTDeclWriter W(*this, Context, Record);
2415 
2416   // Build a record for this declaration
2417   W.Visit(D);
2418 
2419   // Emit this declaration to the bitstream.
2420   uint64_t Offset = W.Emit(D);
2421 
2422   // Record the offset for this declaration
2423   SourceLocation Loc = D->getLocation();
2424   unsigned Index = ID - FirstDeclID;
2425   if (DeclOffsets.size() == Index)
2426     DeclOffsets.emplace_back(Loc, Offset, DeclTypesBlockStartOffset);
2427   else if (DeclOffsets.size() < Index) {
2428     // FIXME: Can/should this happen?
2429     DeclOffsets.resize(Index+1);
2430     DeclOffsets[Index].setLocation(Loc);
2431     DeclOffsets[Index].setBitOffset(Offset, DeclTypesBlockStartOffset);
2432   } else {
2433     llvm_unreachable("declarations should be emitted in ID order");
2434   }
2435 
2436   SourceManager &SM = Context.getSourceManager();
2437   if (Loc.isValid() && SM.isLocalSourceLocation(Loc))
2438     associateDeclWithFile(D, ID);
2439 
2440   // Note declarations that should be deserialized eagerly so that we can add
2441   // them to a record in the AST file later.
2442   if (isRequiredDecl(D, Context, WritingModule))
2443     EagerlyDeserializedDecls.push_back(ID);
2444 }
2445 
2446 void ASTRecordWriter::AddFunctionDefinition(const FunctionDecl *FD) {
2447   // Switch case IDs are per function body.
2448   Writer->ClearSwitchCaseIDs();
2449 
2450   assert(FD->doesThisDeclarationHaveABody());
2451   bool ModulesCodegen = false;
2452   if (!FD->isDependentContext()) {
2453     Optional<GVALinkage> Linkage;
2454     if (Writer->WritingModule &&
2455         Writer->WritingModule->Kind == Module::ModuleInterfaceUnit) {
2456       // When building a C++ Modules TS module interface unit, a strong
2457       // definition in the module interface is provided by the compilation of
2458       // that module interface unit, not by its users. (Inline functions are
2459       // still emitted in module users.)
2460       Linkage = Writer->Context->GetGVALinkageForFunction(FD);
2461       ModulesCodegen = *Linkage == GVA_StrongExternal;
2462     }
2463     if (Writer->Context->getLangOpts().ModulesCodegen ||
2464         (FD->hasAttr<DLLExportAttr>() &&
2465          Writer->Context->getLangOpts().BuildingPCHWithObjectFile)) {
2466 
2467       // Under -fmodules-codegen, codegen is performed for all non-internal,
2468       // non-always_inline functions, unless they are available elsewhere.
2469       if (!FD->hasAttr<AlwaysInlineAttr>()) {
2470         if (!Linkage)
2471           Linkage = Writer->Context->GetGVALinkageForFunction(FD);
2472         ModulesCodegen =
2473             *Linkage != GVA_Internal && *Linkage != GVA_AvailableExternally;
2474       }
2475     }
2476   }
2477   Record->push_back(ModulesCodegen);
2478   if (ModulesCodegen)
2479     Writer->ModularCodegenDecls.push_back(Writer->GetDeclRef(FD));
2480   if (auto *CD = dyn_cast<CXXConstructorDecl>(FD)) {
2481     Record->push_back(CD->getNumCtorInitializers());
2482     if (CD->getNumCtorInitializers())
2483       AddCXXCtorInitializers(
2484           llvm::makeArrayRef(CD->init_begin(), CD->init_end()));
2485   }
2486   AddStmt(FD->getBody());
2487 }
2488