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/DeclContextInternals.h"
17 #include "clang/AST/DeclTemplate.h"
18 #include "clang/AST/DeclVisitor.h"
19 #include "clang/AST/Expr.h"
20 #include "clang/AST/OpenMPClause.h"
21 #include "clang/AST/PrettyDeclStackTrace.h"
22 #include "clang/Basic/SourceManager.h"
23 #include "clang/Serialization/ASTReader.h"
24 #include "clang/Serialization/ASTRecordWriter.h"
25 #include "llvm/Bitstream/BitstreamWriter.h"
26 #include "llvm/Support/ErrorHandling.h"
27 using namespace clang;
28 using namespace serialization;
29 
30 //===----------------------------------------------------------------------===//
31 // Declaration serialization
32 //===----------------------------------------------------------------------===//
33 
34 namespace clang {
35   class ASTDeclWriter : public DeclVisitor<ASTDeclWriter, void> {
36     ASTWriter &Writer;
37     ASTContext &Context;
38     ASTRecordWriter Record;
39 
40     serialization::DeclCode Code;
41     unsigned AbbrevToUse;
42 
43   public:
44     ASTDeclWriter(ASTWriter &Writer, ASTContext &Context,
45                   ASTWriter::RecordDataImpl &Record)
46         : Writer(Writer), Context(Context), Record(Writer, Record),
47           Code((serialization::DeclCode)0), AbbrevToUse(0) {}
48 
49     uint64_t Emit(Decl *D) {
50       if (!Code)
51         llvm::report_fatal_error(StringRef("unexpected declaration kind '") +
52             D->getDeclKindName() + "'");
53       return Record.Emit(Code, AbbrevToUse);
54     }
55 
56     void Visit(Decl *D);
57 
58     void VisitDecl(Decl *D);
59     void VisitPragmaCommentDecl(PragmaCommentDecl *D);
60     void VisitPragmaDetectMismatchDecl(PragmaDetectMismatchDecl *D);
61     void VisitTranslationUnitDecl(TranslationUnitDecl *D);
62     void VisitNamedDecl(NamedDecl *D);
63     void VisitLabelDecl(LabelDecl *LD);
64     void VisitNamespaceDecl(NamespaceDecl *D);
65     void VisitUsingDirectiveDecl(UsingDirectiveDecl *D);
66     void VisitNamespaceAliasDecl(NamespaceAliasDecl *D);
67     void VisitTypeDecl(TypeDecl *D);
68     void VisitTypedefNameDecl(TypedefNameDecl *D);
69     void VisitTypedefDecl(TypedefDecl *D);
70     void VisitTypeAliasDecl(TypeAliasDecl *D);
71     void VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *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   VisitFunctionDecl(D);
677   Record.push_back(D->isCopyDeductionCandidate());
678   Code = serialization::DECL_CXX_DEDUCTION_GUIDE;
679 }
680 
681 void ASTDeclWriter::VisitObjCMethodDecl(ObjCMethodDecl *D) {
682   VisitNamedDecl(D);
683   // FIXME: convert to LazyStmtPtr?
684   // Unlike C/C++, method bodies will never be in header files.
685   bool HasBodyStuff = D->getBody() != nullptr;
686   Record.push_back(HasBodyStuff);
687   if (HasBodyStuff) {
688     Record.AddStmt(D->getBody());
689   }
690   Record.AddDeclRef(D->getSelfDecl());
691   Record.AddDeclRef(D->getCmdDecl());
692   Record.push_back(D->isInstanceMethod());
693   Record.push_back(D->isVariadic());
694   Record.push_back(D->isPropertyAccessor());
695   Record.push_back(D->isSynthesizedAccessorStub());
696   Record.push_back(D->isDefined());
697   Record.push_back(D->isOverriding());
698   Record.push_back(D->hasSkippedBody());
699 
700   Record.push_back(D->isRedeclaration());
701   Record.push_back(D->hasRedeclaration());
702   if (D->hasRedeclaration()) {
703     assert(Context.getObjCMethodRedeclaration(D));
704     Record.AddDeclRef(Context.getObjCMethodRedeclaration(D));
705   }
706 
707   // FIXME: stable encoding for @required/@optional
708   Record.push_back(D->getImplementationControl());
709   // FIXME: stable encoding for in/out/inout/bycopy/byref/oneway/nullability
710   Record.push_back(D->getObjCDeclQualifier());
711   Record.push_back(D->hasRelatedResultType());
712   Record.AddTypeRef(D->getReturnType());
713   Record.AddTypeSourceInfo(D->getReturnTypeSourceInfo());
714   Record.AddSourceLocation(D->getEndLoc());
715   Record.push_back(D->param_size());
716   for (const auto *P : D->parameters())
717     Record.AddDeclRef(P);
718 
719   Record.push_back(D->getSelLocsKind());
720   unsigned NumStoredSelLocs = D->getNumStoredSelLocs();
721   SourceLocation *SelLocs = D->getStoredSelLocs();
722   Record.push_back(NumStoredSelLocs);
723   for (unsigned i = 0; i != NumStoredSelLocs; ++i)
724     Record.AddSourceLocation(SelLocs[i]);
725 
726   Code = serialization::DECL_OBJC_METHOD;
727 }
728 
729 void ASTDeclWriter::VisitObjCTypeParamDecl(ObjCTypeParamDecl *D) {
730   VisitTypedefNameDecl(D);
731   Record.push_back(D->Variance);
732   Record.push_back(D->Index);
733   Record.AddSourceLocation(D->VarianceLoc);
734   Record.AddSourceLocation(D->ColonLoc);
735 
736   Code = serialization::DECL_OBJC_TYPE_PARAM;
737 }
738 
739 void ASTDeclWriter::VisitObjCContainerDecl(ObjCContainerDecl *D) {
740   VisitNamedDecl(D);
741   Record.AddSourceLocation(D->getAtStartLoc());
742   Record.AddSourceRange(D->getAtEndRange());
743   // Abstract class (no need to define a stable serialization::DECL code).
744 }
745 
746 void ASTDeclWriter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
747   VisitRedeclarable(D);
748   VisitObjCContainerDecl(D);
749   Record.AddTypeRef(QualType(D->getTypeForDecl(), 0));
750   AddObjCTypeParamList(D->TypeParamList);
751 
752   Record.push_back(D->isThisDeclarationADefinition());
753   if (D->isThisDeclarationADefinition()) {
754     // Write the DefinitionData
755     ObjCInterfaceDecl::DefinitionData &Data = D->data();
756 
757     Record.AddTypeSourceInfo(D->getSuperClassTInfo());
758     Record.AddSourceLocation(D->getEndOfDefinitionLoc());
759     Record.push_back(Data.HasDesignatedInitializers);
760 
761     // Write out the protocols that are directly referenced by the @interface.
762     Record.push_back(Data.ReferencedProtocols.size());
763     for (const auto *P : D->protocols())
764       Record.AddDeclRef(P);
765     for (const auto &PL : D->protocol_locs())
766       Record.AddSourceLocation(PL);
767 
768     // Write out the protocols that are transitively referenced.
769     Record.push_back(Data.AllReferencedProtocols.size());
770     for (ObjCList<ObjCProtocolDecl>::iterator
771               P = Data.AllReferencedProtocols.begin(),
772            PEnd = Data.AllReferencedProtocols.end();
773          P != PEnd; ++P)
774       Record.AddDeclRef(*P);
775 
776 
777     if (ObjCCategoryDecl *Cat = D->getCategoryListRaw()) {
778       // Ensure that we write out the set of categories for this class.
779       Writer.ObjCClassesWithCategories.insert(D);
780 
781       // Make sure that the categories get serialized.
782       for (; Cat; Cat = Cat->getNextClassCategoryRaw())
783         (void)Writer.GetDeclRef(Cat);
784     }
785   }
786 
787   Code = serialization::DECL_OBJC_INTERFACE;
788 }
789 
790 void ASTDeclWriter::VisitObjCIvarDecl(ObjCIvarDecl *D) {
791   VisitFieldDecl(D);
792   // FIXME: stable encoding for @public/@private/@protected/@package
793   Record.push_back(D->getAccessControl());
794   Record.push_back(D->getSynthesize());
795 
796   if (D->getDeclContext() == D->getLexicalDeclContext() &&
797       !D->hasAttrs() &&
798       !D->isImplicit() &&
799       !D->isUsed(false) &&
800       !D->isInvalidDecl() &&
801       !D->isReferenced() &&
802       !D->isModulePrivate() &&
803       !D->getBitWidth() &&
804       !D->hasExtInfo() &&
805       D->getDeclName())
806     AbbrevToUse = Writer.getDeclObjCIvarAbbrev();
807 
808   Code = serialization::DECL_OBJC_IVAR;
809 }
810 
811 void ASTDeclWriter::VisitObjCProtocolDecl(ObjCProtocolDecl *D) {
812   VisitRedeclarable(D);
813   VisitObjCContainerDecl(D);
814 
815   Record.push_back(D->isThisDeclarationADefinition());
816   if (D->isThisDeclarationADefinition()) {
817     Record.push_back(D->protocol_size());
818     for (const auto *I : D->protocols())
819       Record.AddDeclRef(I);
820     for (const auto &PL : D->protocol_locs())
821       Record.AddSourceLocation(PL);
822   }
823 
824   Code = serialization::DECL_OBJC_PROTOCOL;
825 }
826 
827 void ASTDeclWriter::VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D) {
828   VisitFieldDecl(D);
829   Code = serialization::DECL_OBJC_AT_DEFS_FIELD;
830 }
831 
832 void ASTDeclWriter::VisitObjCCategoryDecl(ObjCCategoryDecl *D) {
833   VisitObjCContainerDecl(D);
834   Record.AddSourceLocation(D->getCategoryNameLoc());
835   Record.AddSourceLocation(D->getIvarLBraceLoc());
836   Record.AddSourceLocation(D->getIvarRBraceLoc());
837   Record.AddDeclRef(D->getClassInterface());
838   AddObjCTypeParamList(D->TypeParamList);
839   Record.push_back(D->protocol_size());
840   for (const auto *I : D->protocols())
841     Record.AddDeclRef(I);
842   for (const auto &PL : D->protocol_locs())
843     Record.AddSourceLocation(PL);
844   Code = serialization::DECL_OBJC_CATEGORY;
845 }
846 
847 void ASTDeclWriter::VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D) {
848   VisitNamedDecl(D);
849   Record.AddDeclRef(D->getClassInterface());
850   Code = serialization::DECL_OBJC_COMPATIBLE_ALIAS;
851 }
852 
853 void ASTDeclWriter::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
854   VisitNamedDecl(D);
855   Record.AddSourceLocation(D->getAtLoc());
856   Record.AddSourceLocation(D->getLParenLoc());
857   Record.AddTypeRef(D->getType());
858   Record.AddTypeSourceInfo(D->getTypeSourceInfo());
859   // FIXME: stable encoding
860   Record.push_back((unsigned)D->getPropertyAttributes());
861   Record.push_back((unsigned)D->getPropertyAttributesAsWritten());
862   // FIXME: stable encoding
863   Record.push_back((unsigned)D->getPropertyImplementation());
864   Record.AddDeclarationName(D->getGetterName());
865   Record.AddSourceLocation(D->getGetterNameLoc());
866   Record.AddDeclarationName(D->getSetterName());
867   Record.AddSourceLocation(D->getSetterNameLoc());
868   Record.AddDeclRef(D->getGetterMethodDecl());
869   Record.AddDeclRef(D->getSetterMethodDecl());
870   Record.AddDeclRef(D->getPropertyIvarDecl());
871   Code = serialization::DECL_OBJC_PROPERTY;
872 }
873 
874 void ASTDeclWriter::VisitObjCImplDecl(ObjCImplDecl *D) {
875   VisitObjCContainerDecl(D);
876   Record.AddDeclRef(D->getClassInterface());
877   // Abstract class (no need to define a stable serialization::DECL code).
878 }
879 
880 void ASTDeclWriter::VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D) {
881   VisitObjCImplDecl(D);
882   Record.AddSourceLocation(D->getCategoryNameLoc());
883   Code = serialization::DECL_OBJC_CATEGORY_IMPL;
884 }
885 
886 void ASTDeclWriter::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
887   VisitObjCImplDecl(D);
888   Record.AddDeclRef(D->getSuperClass());
889   Record.AddSourceLocation(D->getSuperClassLoc());
890   Record.AddSourceLocation(D->getIvarLBraceLoc());
891   Record.AddSourceLocation(D->getIvarRBraceLoc());
892   Record.push_back(D->hasNonZeroConstructors());
893   Record.push_back(D->hasDestructors());
894   Record.push_back(D->NumIvarInitializers);
895   if (D->NumIvarInitializers)
896     Record.AddCXXCtorInitializers(
897         llvm::makeArrayRef(D->init_begin(), D->init_end()));
898   Code = serialization::DECL_OBJC_IMPLEMENTATION;
899 }
900 
901 void ASTDeclWriter::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
902   VisitDecl(D);
903   Record.AddSourceLocation(D->getBeginLoc());
904   Record.AddDeclRef(D->getPropertyDecl());
905   Record.AddDeclRef(D->getPropertyIvarDecl());
906   Record.AddSourceLocation(D->getPropertyIvarDeclLoc());
907   Record.AddDeclRef(D->getGetterMethodDecl());
908   Record.AddDeclRef(D->getSetterMethodDecl());
909   Record.AddStmt(D->getGetterCXXConstructor());
910   Record.AddStmt(D->getSetterCXXAssignment());
911   Code = serialization::DECL_OBJC_PROPERTY_IMPL;
912 }
913 
914 void ASTDeclWriter::VisitFieldDecl(FieldDecl *D) {
915   VisitDeclaratorDecl(D);
916   Record.push_back(D->isMutable());
917 
918   FieldDecl::InitStorageKind ISK = D->InitStorage.getInt();
919   Record.push_back(ISK);
920   if (ISK == FieldDecl::ISK_CapturedVLAType)
921     Record.AddTypeRef(QualType(D->getCapturedVLAType(), 0));
922   else if (ISK)
923     Record.AddStmt(D->getInClassInitializer());
924 
925   Record.AddStmt(D->getBitWidth());
926 
927   if (!D->getDeclName())
928     Record.AddDeclRef(Context.getInstantiatedFromUnnamedFieldDecl(D));
929 
930   if (D->getDeclContext() == D->getLexicalDeclContext() &&
931       !D->hasAttrs() &&
932       !D->isImplicit() &&
933       !D->isUsed(false) &&
934       !D->isInvalidDecl() &&
935       !D->isReferenced() &&
936       !D->isTopLevelDeclInObjCContainer() &&
937       !D->isModulePrivate() &&
938       !D->getBitWidth() &&
939       !D->hasInClassInitializer() &&
940       !D->hasCapturedVLAType() &&
941       !D->hasExtInfo() &&
942       !ObjCIvarDecl::classofKind(D->getKind()) &&
943       !ObjCAtDefsFieldDecl::classofKind(D->getKind()) &&
944       D->getDeclName())
945     AbbrevToUse = Writer.getDeclFieldAbbrev();
946 
947   Code = serialization::DECL_FIELD;
948 }
949 
950 void ASTDeclWriter::VisitMSPropertyDecl(MSPropertyDecl *D) {
951   VisitDeclaratorDecl(D);
952   Record.AddIdentifierRef(D->getGetterId());
953   Record.AddIdentifierRef(D->getSetterId());
954   Code = serialization::DECL_MS_PROPERTY;
955 }
956 
957 void ASTDeclWriter::VisitMSGuidDecl(MSGuidDecl *D) {
958   VisitValueDecl(D);
959   MSGuidDecl::Parts Parts = D->getParts();
960   Record.push_back(Parts.Part1);
961   Record.push_back(Parts.Part2);
962   Record.push_back(Parts.Part3);
963   for (auto C : Parts.Part4And5)
964     Record.push_back(C);
965   Code = serialization::DECL_MS_GUID;
966 }
967 
968 void ASTDeclWriter::VisitTemplateParamObjectDecl(TemplateParamObjectDecl *D) {
969   VisitValueDecl(D);
970   Record.AddAPValue(D->getValue());
971   Code = serialization::DECL_TEMPLATE_PARAM_OBJECT;
972 }
973 
974 void ASTDeclWriter::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
975   VisitValueDecl(D);
976   Record.push_back(D->getChainingSize());
977 
978   for (const auto *P : D->chain())
979     Record.AddDeclRef(P);
980   Code = serialization::DECL_INDIRECTFIELD;
981 }
982 
983 void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
984   VisitRedeclarable(D);
985   VisitDeclaratorDecl(D);
986   Record.push_back(D->getStorageClass());
987   Record.push_back(D->getTSCSpec());
988   Record.push_back(D->getInitStyle());
989   Record.push_back(D->isARCPseudoStrong());
990   if (!isa<ParmVarDecl>(D)) {
991     Record.push_back(D->isThisDeclarationADemotedDefinition());
992     Record.push_back(D->isExceptionVariable());
993     Record.push_back(D->isNRVOVariable());
994     Record.push_back(D->isCXXForRangeDecl());
995     Record.push_back(D->isObjCForDecl());
996     Record.push_back(D->isInline());
997     Record.push_back(D->isInlineSpecified());
998     Record.push_back(D->isConstexpr());
999     Record.push_back(D->isInitCapture());
1000     Record.push_back(D->isPreviousDeclInSameBlockScope());
1001     if (const auto *IPD = dyn_cast<ImplicitParamDecl>(D))
1002       Record.push_back(static_cast<unsigned>(IPD->getParameterKind()));
1003     else
1004       Record.push_back(0);
1005     Record.push_back(D->isEscapingByref());
1006   }
1007   Record.push_back(D->getLinkageInternal());
1008 
1009   Record.AddVarDeclInit(D);
1010 
1011   if (D->hasAttr<BlocksAttr>() && D->getType()->getAsCXXRecordDecl()) {
1012     BlockVarCopyInit Init = Writer.Context->getBlockVarCopyInit(D);
1013     Record.AddStmt(Init.getCopyExpr());
1014     if (Init.getCopyExpr())
1015       Record.push_back(Init.canThrow());
1016   }
1017 
1018   if (D->getStorageDuration() == SD_Static) {
1019     bool ModulesCodegen = false;
1020     if (Writer.WritingModule &&
1021         !D->getDescribedVarTemplate() && !D->getMemberSpecializationInfo() &&
1022         !isa<VarTemplateSpecializationDecl>(D)) {
1023       // When building a C++ Modules TS module interface unit, a strong
1024       // definition in the module interface is provided by the compilation of
1025       // that module interface unit, not by its users. (Inline variables are
1026       // still emitted in module users.)
1027       ModulesCodegen =
1028           (Writer.WritingModule->Kind == Module::ModuleInterfaceUnit ||
1029            (D->hasAttr<DLLExportAttr>() &&
1030             Writer.Context->getLangOpts().BuildingPCHWithObjectFile)) &&
1031           Writer.Context->GetGVALinkageForVariable(D) == GVA_StrongExternal;
1032     }
1033     Record.push_back(ModulesCodegen);
1034     if (ModulesCodegen)
1035       Writer.ModularCodegenDecls.push_back(Writer.GetDeclRef(D));
1036   }
1037 
1038   enum {
1039     VarNotTemplate = 0, VarTemplate, StaticDataMemberSpecialization
1040   };
1041   if (VarTemplateDecl *TemplD = D->getDescribedVarTemplate()) {
1042     Record.push_back(VarTemplate);
1043     Record.AddDeclRef(TemplD);
1044   } else if (MemberSpecializationInfo *SpecInfo
1045                = D->getMemberSpecializationInfo()) {
1046     Record.push_back(StaticDataMemberSpecialization);
1047     Record.AddDeclRef(SpecInfo->getInstantiatedFrom());
1048     Record.push_back(SpecInfo->getTemplateSpecializationKind());
1049     Record.AddSourceLocation(SpecInfo->getPointOfInstantiation());
1050   } else {
1051     Record.push_back(VarNotTemplate);
1052   }
1053 
1054   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1055       !D->hasAttrs() &&
1056       !D->isImplicit() &&
1057       !D->isUsed(false) &&
1058       !D->isInvalidDecl() &&
1059       !D->isReferenced() &&
1060       !D->isTopLevelDeclInObjCContainer() &&
1061       D->getAccess() == AS_none &&
1062       !D->isModulePrivate() &&
1063       !needsAnonymousDeclarationNumber(D) &&
1064       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1065       !D->hasExtInfo() &&
1066       D->getFirstDecl() == D->getMostRecentDecl() &&
1067       D->getKind() == Decl::Var &&
1068       !D->isInline() &&
1069       !D->isConstexpr() &&
1070       !D->isInitCapture() &&
1071       !D->isPreviousDeclInSameBlockScope() &&
1072       !(D->hasAttr<BlocksAttr>() && D->getType()->getAsCXXRecordDecl()) &&
1073       !D->isEscapingByref() &&
1074       D->getStorageDuration() != SD_Static &&
1075       !D->getMemberSpecializationInfo())
1076     AbbrevToUse = Writer.getDeclVarAbbrev();
1077 
1078   Code = serialization::DECL_VAR;
1079 }
1080 
1081 void ASTDeclWriter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
1082   VisitVarDecl(D);
1083   Code = serialization::DECL_IMPLICIT_PARAM;
1084 }
1085 
1086 void ASTDeclWriter::VisitParmVarDecl(ParmVarDecl *D) {
1087   VisitVarDecl(D);
1088   Record.push_back(D->isObjCMethodParameter());
1089   Record.push_back(D->getFunctionScopeDepth());
1090   Record.push_back(D->getFunctionScopeIndex());
1091   Record.push_back(D->getObjCDeclQualifier()); // FIXME: stable encoding
1092   Record.push_back(D->isKNRPromoted());
1093   Record.push_back(D->hasInheritedDefaultArg());
1094   Record.push_back(D->hasUninstantiatedDefaultArg());
1095   if (D->hasUninstantiatedDefaultArg())
1096     Record.AddStmt(D->getUninstantiatedDefaultArg());
1097   Code = serialization::DECL_PARM_VAR;
1098 
1099   // If the assumptions about the DECL_PARM_VAR abbrev are true, use it.  Here
1100   // we dynamically check for the properties that we optimize for, but don't
1101   // know are true of all PARM_VAR_DECLs.
1102   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1103       !D->hasAttrs() &&
1104       !D->hasExtInfo() &&
1105       !D->isImplicit() &&
1106       !D->isUsed(false) &&
1107       !D->isInvalidDecl() &&
1108       !D->isReferenced() &&
1109       D->getAccess() == AS_none &&
1110       !D->isModulePrivate() &&
1111       D->getStorageClass() == 0 &&
1112       D->getInitStyle() == VarDecl::CInit && // Can params have anything else?
1113       D->getFunctionScopeDepth() == 0 &&
1114       D->getObjCDeclQualifier() == 0 &&
1115       !D->isKNRPromoted() &&
1116       !D->hasInheritedDefaultArg() &&
1117       D->getInit() == nullptr &&
1118       !D->hasUninstantiatedDefaultArg())  // No default expr.
1119     AbbrevToUse = Writer.getDeclParmVarAbbrev();
1120 
1121   // Check things we know are true of *every* PARM_VAR_DECL, which is more than
1122   // just us assuming it.
1123   assert(!D->getTSCSpec() && "PARM_VAR_DECL can't use TLS");
1124   assert(!D->isThisDeclarationADemotedDefinition()
1125          && "PARM_VAR_DECL can't be demoted definition.");
1126   assert(D->getAccess() == AS_none && "PARM_VAR_DECL can't be public/private");
1127   assert(!D->isExceptionVariable() && "PARM_VAR_DECL can't be exception var");
1128   assert(D->getPreviousDecl() == nullptr && "PARM_VAR_DECL can't be redecl");
1129   assert(!D->isStaticDataMember() &&
1130          "PARM_VAR_DECL can't be static data member");
1131 }
1132 
1133 void ASTDeclWriter::VisitDecompositionDecl(DecompositionDecl *D) {
1134   // Record the number of bindings first to simplify deserialization.
1135   Record.push_back(D->bindings().size());
1136 
1137   VisitVarDecl(D);
1138   for (auto *B : D->bindings())
1139     Record.AddDeclRef(B);
1140   Code = serialization::DECL_DECOMPOSITION;
1141 }
1142 
1143 void ASTDeclWriter::VisitBindingDecl(BindingDecl *D) {
1144   VisitValueDecl(D);
1145   Record.AddStmt(D->getBinding());
1146   Code = serialization::DECL_BINDING;
1147 }
1148 
1149 void ASTDeclWriter::VisitFileScopeAsmDecl(FileScopeAsmDecl *D) {
1150   VisitDecl(D);
1151   Record.AddStmt(D->getAsmString());
1152   Record.AddSourceLocation(D->getRParenLoc());
1153   Code = serialization::DECL_FILE_SCOPE_ASM;
1154 }
1155 
1156 void ASTDeclWriter::VisitEmptyDecl(EmptyDecl *D) {
1157   VisitDecl(D);
1158   Code = serialization::DECL_EMPTY;
1159 }
1160 
1161 void ASTDeclWriter::VisitLifetimeExtendedTemporaryDecl(
1162     LifetimeExtendedTemporaryDecl *D) {
1163   VisitDecl(D);
1164   Record.AddDeclRef(D->getExtendingDecl());
1165   Record.AddStmt(D->getTemporaryExpr());
1166   Record.push_back(static_cast<bool>(D->getValue()));
1167   if (D->getValue())
1168     Record.AddAPValue(*D->getValue());
1169   Record.push_back(D->getManglingNumber());
1170   Code = serialization::DECL_LIFETIME_EXTENDED_TEMPORARY;
1171 }
1172 void ASTDeclWriter::VisitBlockDecl(BlockDecl *D) {
1173   VisitDecl(D);
1174   Record.AddStmt(D->getBody());
1175   Record.AddTypeSourceInfo(D->getSignatureAsWritten());
1176   Record.push_back(D->param_size());
1177   for (ParmVarDecl *P : D->parameters())
1178     Record.AddDeclRef(P);
1179   Record.push_back(D->isVariadic());
1180   Record.push_back(D->blockMissingReturnType());
1181   Record.push_back(D->isConversionFromLambda());
1182   Record.push_back(D->doesNotEscape());
1183   Record.push_back(D->canAvoidCopyToHeap());
1184   Record.push_back(D->capturesCXXThis());
1185   Record.push_back(D->getNumCaptures());
1186   for (const auto &capture : D->captures()) {
1187     Record.AddDeclRef(capture.getVariable());
1188 
1189     unsigned flags = 0;
1190     if (capture.isByRef()) flags |= 1;
1191     if (capture.isNested()) flags |= 2;
1192     if (capture.hasCopyExpr()) flags |= 4;
1193     Record.push_back(flags);
1194 
1195     if (capture.hasCopyExpr()) Record.AddStmt(capture.getCopyExpr());
1196   }
1197 
1198   Code = serialization::DECL_BLOCK;
1199 }
1200 
1201 void ASTDeclWriter::VisitCapturedDecl(CapturedDecl *CD) {
1202   Record.push_back(CD->getNumParams());
1203   VisitDecl(CD);
1204   Record.push_back(CD->getContextParamPosition());
1205   Record.push_back(CD->isNothrow() ? 1 : 0);
1206   // Body is stored by VisitCapturedStmt.
1207   for (unsigned I = 0; I < CD->getNumParams(); ++I)
1208     Record.AddDeclRef(CD->getParam(I));
1209   Code = serialization::DECL_CAPTURED;
1210 }
1211 
1212 void ASTDeclWriter::VisitLinkageSpecDecl(LinkageSpecDecl *D) {
1213   VisitDecl(D);
1214   Record.push_back(D->getLanguage());
1215   Record.AddSourceLocation(D->getExternLoc());
1216   Record.AddSourceLocation(D->getRBraceLoc());
1217   Code = serialization::DECL_LINKAGE_SPEC;
1218 }
1219 
1220 void ASTDeclWriter::VisitExportDecl(ExportDecl *D) {
1221   VisitDecl(D);
1222   Record.AddSourceLocation(D->getRBraceLoc());
1223   Code = serialization::DECL_EXPORT;
1224 }
1225 
1226 void ASTDeclWriter::VisitLabelDecl(LabelDecl *D) {
1227   VisitNamedDecl(D);
1228   Record.AddSourceLocation(D->getBeginLoc());
1229   Code = serialization::DECL_LABEL;
1230 }
1231 
1232 
1233 void ASTDeclWriter::VisitNamespaceDecl(NamespaceDecl *D) {
1234   VisitRedeclarable(D);
1235   VisitNamedDecl(D);
1236   Record.push_back(D->isInline());
1237   Record.AddSourceLocation(D->getBeginLoc());
1238   Record.AddSourceLocation(D->getRBraceLoc());
1239 
1240   if (D->isOriginalNamespace())
1241     Record.AddDeclRef(D->getAnonymousNamespace());
1242   Code = serialization::DECL_NAMESPACE;
1243 
1244   if (Writer.hasChain() && D->isAnonymousNamespace() &&
1245       D == D->getMostRecentDecl()) {
1246     // This is a most recent reopening of the anonymous namespace. If its parent
1247     // is in a previous PCH (or is the TU), mark that parent for update, because
1248     // the original namespace always points to the latest re-opening of its
1249     // anonymous namespace.
1250     Decl *Parent = cast<Decl>(
1251         D->getParent()->getRedeclContext()->getPrimaryContext());
1252     if (Parent->isFromASTFile() || isa<TranslationUnitDecl>(Parent)) {
1253       Writer.DeclUpdates[Parent].push_back(
1254           ASTWriter::DeclUpdate(UPD_CXX_ADDED_ANONYMOUS_NAMESPACE, D));
1255     }
1256   }
1257 }
1258 
1259 void ASTDeclWriter::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
1260   VisitRedeclarable(D);
1261   VisitNamedDecl(D);
1262   Record.AddSourceLocation(D->getNamespaceLoc());
1263   Record.AddSourceLocation(D->getTargetNameLoc());
1264   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1265   Record.AddDeclRef(D->getNamespace());
1266   Code = serialization::DECL_NAMESPACE_ALIAS;
1267 }
1268 
1269 void ASTDeclWriter::VisitUsingDecl(UsingDecl *D) {
1270   VisitNamedDecl(D);
1271   Record.AddSourceLocation(D->getUsingLoc());
1272   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1273   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
1274   Record.AddDeclRef(D->FirstUsingShadow.getPointer());
1275   Record.push_back(D->hasTypename());
1276   Record.AddDeclRef(Context.getInstantiatedFromUsingDecl(D));
1277   Code = serialization::DECL_USING;
1278 }
1279 
1280 void ASTDeclWriter::VisitUsingPackDecl(UsingPackDecl *D) {
1281   Record.push_back(D->NumExpansions);
1282   VisitNamedDecl(D);
1283   Record.AddDeclRef(D->getInstantiatedFromUsingDecl());
1284   for (auto *E : D->expansions())
1285     Record.AddDeclRef(E);
1286   Code = serialization::DECL_USING_PACK;
1287 }
1288 
1289 void ASTDeclWriter::VisitUsingShadowDecl(UsingShadowDecl *D) {
1290   VisitRedeclarable(D);
1291   VisitNamedDecl(D);
1292   Record.AddDeclRef(D->getTargetDecl());
1293   Record.push_back(D->getIdentifierNamespace());
1294   Record.AddDeclRef(D->UsingOrNextShadow);
1295   Record.AddDeclRef(Context.getInstantiatedFromUsingShadowDecl(D));
1296   Code = serialization::DECL_USING_SHADOW;
1297 }
1298 
1299 void ASTDeclWriter::VisitConstructorUsingShadowDecl(
1300     ConstructorUsingShadowDecl *D) {
1301   VisitUsingShadowDecl(D);
1302   Record.AddDeclRef(D->NominatedBaseClassShadowDecl);
1303   Record.AddDeclRef(D->ConstructedBaseClassShadowDecl);
1304   Record.push_back(D->IsVirtual);
1305   Code = serialization::DECL_CONSTRUCTOR_USING_SHADOW;
1306 }
1307 
1308 void ASTDeclWriter::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1309   VisitNamedDecl(D);
1310   Record.AddSourceLocation(D->getUsingLoc());
1311   Record.AddSourceLocation(D->getNamespaceKeyLocation());
1312   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1313   Record.AddDeclRef(D->getNominatedNamespace());
1314   Record.AddDeclRef(dyn_cast<Decl>(D->getCommonAncestor()));
1315   Code = serialization::DECL_USING_DIRECTIVE;
1316 }
1317 
1318 void ASTDeclWriter::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1319   VisitValueDecl(D);
1320   Record.AddSourceLocation(D->getUsingLoc());
1321   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1322   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
1323   Record.AddSourceLocation(D->getEllipsisLoc());
1324   Code = serialization::DECL_UNRESOLVED_USING_VALUE;
1325 }
1326 
1327 void ASTDeclWriter::VisitUnresolvedUsingTypenameDecl(
1328                                                UnresolvedUsingTypenameDecl *D) {
1329   VisitTypeDecl(D);
1330   Record.AddSourceLocation(D->getTypenameLoc());
1331   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1332   Record.AddSourceLocation(D->getEllipsisLoc());
1333   Code = serialization::DECL_UNRESOLVED_USING_TYPENAME;
1334 }
1335 
1336 void ASTDeclWriter::VisitCXXRecordDecl(CXXRecordDecl *D) {
1337   VisitRecordDecl(D);
1338 
1339   enum {
1340     CXXRecNotTemplate = 0, CXXRecTemplate, CXXRecMemberSpecialization
1341   };
1342   if (ClassTemplateDecl *TemplD = D->getDescribedClassTemplate()) {
1343     Record.push_back(CXXRecTemplate);
1344     Record.AddDeclRef(TemplD);
1345   } else if (MemberSpecializationInfo *MSInfo
1346                = D->getMemberSpecializationInfo()) {
1347     Record.push_back(CXXRecMemberSpecialization);
1348     Record.AddDeclRef(MSInfo->getInstantiatedFrom());
1349     Record.push_back(MSInfo->getTemplateSpecializationKind());
1350     Record.AddSourceLocation(MSInfo->getPointOfInstantiation());
1351   } else {
1352     Record.push_back(CXXRecNotTemplate);
1353   }
1354 
1355   Record.push_back(D->isThisDeclarationADefinition());
1356   if (D->isThisDeclarationADefinition())
1357     Record.AddCXXDefinitionData(D);
1358 
1359   // Store (what we currently believe to be) the key function to avoid
1360   // deserializing every method so we can compute it.
1361   if (D->isCompleteDefinition())
1362     Record.AddDeclRef(Context.getCurrentKeyFunction(D));
1363 
1364   Code = serialization::DECL_CXX_RECORD;
1365 }
1366 
1367 void ASTDeclWriter::VisitCXXMethodDecl(CXXMethodDecl *D) {
1368   VisitFunctionDecl(D);
1369   if (D->isCanonicalDecl()) {
1370     Record.push_back(D->size_overridden_methods());
1371     for (const CXXMethodDecl *MD : D->overridden_methods())
1372       Record.AddDeclRef(MD);
1373   } else {
1374     // We only need to record overridden methods once for the canonical decl.
1375     Record.push_back(0);
1376   }
1377 
1378   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1379       D->getFirstDecl() == D->getMostRecentDecl() &&
1380       !D->isInvalidDecl() &&
1381       !D->hasAttrs() &&
1382       !D->isTopLevelDeclInObjCContainer() &&
1383       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1384       !D->hasExtInfo() &&
1385       !D->hasInheritedPrototype() &&
1386       D->hasWrittenPrototype())
1387     AbbrevToUse = Writer.getDeclCXXMethodAbbrev();
1388 
1389   Code = serialization::DECL_CXX_METHOD;
1390 }
1391 
1392 void ASTDeclWriter::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1393   Record.push_back(D->getTraillingAllocKind());
1394   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
1395   if (auto Inherited = D->getInheritedConstructor()) {
1396     Record.AddDeclRef(Inherited.getShadowDecl());
1397     Record.AddDeclRef(Inherited.getConstructor());
1398   }
1399 
1400   VisitCXXMethodDecl(D);
1401   Code = serialization::DECL_CXX_CONSTRUCTOR;
1402 }
1403 
1404 void ASTDeclWriter::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1405   VisitCXXMethodDecl(D);
1406 
1407   Record.AddDeclRef(D->getOperatorDelete());
1408   if (D->getOperatorDelete())
1409     Record.AddStmt(D->getOperatorDeleteThisArg());
1410 
1411   Code = serialization::DECL_CXX_DESTRUCTOR;
1412 }
1413 
1414 void ASTDeclWriter::VisitCXXConversionDecl(CXXConversionDecl *D) {
1415   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
1416   VisitCXXMethodDecl(D);
1417   Code = serialization::DECL_CXX_CONVERSION;
1418 }
1419 
1420 void ASTDeclWriter::VisitImportDecl(ImportDecl *D) {
1421   VisitDecl(D);
1422   Record.push_back(Writer.getSubmoduleID(D->getImportedModule()));
1423   ArrayRef<SourceLocation> IdentifierLocs = D->getIdentifierLocs();
1424   Record.push_back(!IdentifierLocs.empty());
1425   if (IdentifierLocs.empty()) {
1426     Record.AddSourceLocation(D->getEndLoc());
1427     Record.push_back(1);
1428   } else {
1429     for (unsigned I = 0, N = IdentifierLocs.size(); I != N; ++I)
1430       Record.AddSourceLocation(IdentifierLocs[I]);
1431     Record.push_back(IdentifierLocs.size());
1432   }
1433   // Note: the number of source locations must always be the last element in
1434   // the record.
1435   Code = serialization::DECL_IMPORT;
1436 }
1437 
1438 void ASTDeclWriter::VisitAccessSpecDecl(AccessSpecDecl *D) {
1439   VisitDecl(D);
1440   Record.AddSourceLocation(D->getColonLoc());
1441   Code = serialization::DECL_ACCESS_SPEC;
1442 }
1443 
1444 void ASTDeclWriter::VisitFriendDecl(FriendDecl *D) {
1445   // Record the number of friend type template parameter lists here
1446   // so as to simplify memory allocation during deserialization.
1447   Record.push_back(D->NumTPLists);
1448   VisitDecl(D);
1449   bool hasFriendDecl = D->Friend.is<NamedDecl*>();
1450   Record.push_back(hasFriendDecl);
1451   if (hasFriendDecl)
1452     Record.AddDeclRef(D->getFriendDecl());
1453   else
1454     Record.AddTypeSourceInfo(D->getFriendType());
1455   for (unsigned i = 0; i < D->NumTPLists; ++i)
1456     Record.AddTemplateParameterList(D->getFriendTypeTemplateParameterList(i));
1457   Record.AddDeclRef(D->getNextFriend());
1458   Record.push_back(D->UnsupportedFriend);
1459   Record.AddSourceLocation(D->FriendLoc);
1460   Code = serialization::DECL_FRIEND;
1461 }
1462 
1463 void ASTDeclWriter::VisitFriendTemplateDecl(FriendTemplateDecl *D) {
1464   VisitDecl(D);
1465   Record.push_back(D->getNumTemplateParameters());
1466   for (unsigned i = 0, e = D->getNumTemplateParameters(); i != e; ++i)
1467     Record.AddTemplateParameterList(D->getTemplateParameterList(i));
1468   Record.push_back(D->getFriendDecl() != nullptr);
1469   if (D->getFriendDecl())
1470     Record.AddDeclRef(D->getFriendDecl());
1471   else
1472     Record.AddTypeSourceInfo(D->getFriendType());
1473   Record.AddSourceLocation(D->getFriendLoc());
1474   Code = serialization::DECL_FRIEND_TEMPLATE;
1475 }
1476 
1477 void ASTDeclWriter::VisitTemplateDecl(TemplateDecl *D) {
1478   VisitNamedDecl(D);
1479 
1480   Record.AddDeclRef(D->getTemplatedDecl());
1481   Record.AddTemplateParameterList(D->getTemplateParameters());
1482 }
1483 
1484 void ASTDeclWriter::VisitConceptDecl(ConceptDecl *D) {
1485   VisitTemplateDecl(D);
1486   Record.AddStmt(D->getConstraintExpr());
1487   Code = serialization::DECL_CONCEPT;
1488 }
1489 
1490 void ASTDeclWriter::VisitRequiresExprBodyDecl(RequiresExprBodyDecl *D) {
1491   Code = serialization::DECL_REQUIRES_EXPR_BODY;
1492 }
1493 
1494 void ASTDeclWriter::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
1495   VisitRedeclarable(D);
1496 
1497   // Emit data to initialize CommonOrPrev before VisitTemplateDecl so that
1498   // getCommonPtr() can be used while this is still initializing.
1499   if (D->isFirstDecl()) {
1500     // This declaration owns the 'common' pointer, so serialize that data now.
1501     Record.AddDeclRef(D->getInstantiatedFromMemberTemplate());
1502     if (D->getInstantiatedFromMemberTemplate())
1503       Record.push_back(D->isMemberSpecialization());
1504   }
1505 
1506   VisitTemplateDecl(D);
1507   Record.push_back(D->getIdentifierNamespace());
1508 }
1509 
1510 void ASTDeclWriter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
1511   VisitRedeclarableTemplateDecl(D);
1512 
1513   if (D->isFirstDecl())
1514     AddTemplateSpecializations(D);
1515   Code = serialization::DECL_CLASS_TEMPLATE;
1516 }
1517 
1518 void ASTDeclWriter::VisitClassTemplateSpecializationDecl(
1519                                            ClassTemplateSpecializationDecl *D) {
1520   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1521 
1522   VisitCXXRecordDecl(D);
1523 
1524   llvm::PointerUnion<ClassTemplateDecl *,
1525                      ClassTemplatePartialSpecializationDecl *> InstFrom
1526     = D->getSpecializedTemplateOrPartial();
1527   if (Decl *InstFromD = InstFrom.dyn_cast<ClassTemplateDecl *>()) {
1528     Record.AddDeclRef(InstFromD);
1529   } else {
1530     Record.AddDeclRef(InstFrom.get<ClassTemplatePartialSpecializationDecl *>());
1531     Record.AddTemplateArgumentList(&D->getTemplateInstantiationArgs());
1532   }
1533 
1534   Record.AddTemplateArgumentList(&D->getTemplateArgs());
1535   Record.AddSourceLocation(D->getPointOfInstantiation());
1536   Record.push_back(D->getSpecializationKind());
1537   Record.push_back(D->isCanonicalDecl());
1538 
1539   if (D->isCanonicalDecl()) {
1540     // When reading, we'll add it to the folding set of the following template.
1541     Record.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl());
1542   }
1543 
1544   // Explicit info.
1545   Record.AddTypeSourceInfo(D->getTypeAsWritten());
1546   if (D->getTypeAsWritten()) {
1547     Record.AddSourceLocation(D->getExternLoc());
1548     Record.AddSourceLocation(D->getTemplateKeywordLoc());
1549   }
1550 
1551   Code = serialization::DECL_CLASS_TEMPLATE_SPECIALIZATION;
1552 }
1553 
1554 void ASTDeclWriter::VisitClassTemplatePartialSpecializationDecl(
1555                                     ClassTemplatePartialSpecializationDecl *D) {
1556   Record.AddTemplateParameterList(D->getTemplateParameters());
1557   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1558 
1559   VisitClassTemplateSpecializationDecl(D);
1560 
1561   // These are read/set from/to the first declaration.
1562   if (D->getPreviousDecl() == nullptr) {
1563     Record.AddDeclRef(D->getInstantiatedFromMember());
1564     Record.push_back(D->isMemberSpecialization());
1565   }
1566 
1567   Code = serialization::DECL_CLASS_TEMPLATE_PARTIAL_SPECIALIZATION;
1568 }
1569 
1570 void ASTDeclWriter::VisitVarTemplateDecl(VarTemplateDecl *D) {
1571   VisitRedeclarableTemplateDecl(D);
1572 
1573   if (D->isFirstDecl())
1574     AddTemplateSpecializations(D);
1575   Code = serialization::DECL_VAR_TEMPLATE;
1576 }
1577 
1578 void ASTDeclWriter::VisitVarTemplateSpecializationDecl(
1579     VarTemplateSpecializationDecl *D) {
1580   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1581 
1582   VisitVarDecl(D);
1583 
1584   llvm::PointerUnion<VarTemplateDecl *, VarTemplatePartialSpecializationDecl *>
1585   InstFrom = D->getSpecializedTemplateOrPartial();
1586   if (Decl *InstFromD = InstFrom.dyn_cast<VarTemplateDecl *>()) {
1587     Record.AddDeclRef(InstFromD);
1588   } else {
1589     Record.AddDeclRef(InstFrom.get<VarTemplatePartialSpecializationDecl *>());
1590     Record.AddTemplateArgumentList(&D->getTemplateInstantiationArgs());
1591   }
1592 
1593   // Explicit info.
1594   Record.AddTypeSourceInfo(D->getTypeAsWritten());
1595   if (D->getTypeAsWritten()) {
1596     Record.AddSourceLocation(D->getExternLoc());
1597     Record.AddSourceLocation(D->getTemplateKeywordLoc());
1598   }
1599 
1600   Record.AddTemplateArgumentList(&D->getTemplateArgs());
1601   Record.AddSourceLocation(D->getPointOfInstantiation());
1602   Record.push_back(D->getSpecializationKind());
1603   Record.push_back(D->IsCompleteDefinition);
1604   Record.push_back(D->isCanonicalDecl());
1605 
1606   if (D->isCanonicalDecl()) {
1607     // When reading, we'll add it to the folding set of the following template.
1608     Record.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl());
1609   }
1610 
1611   Code = serialization::DECL_VAR_TEMPLATE_SPECIALIZATION;
1612 }
1613 
1614 void ASTDeclWriter::VisitVarTemplatePartialSpecializationDecl(
1615     VarTemplatePartialSpecializationDecl *D) {
1616   Record.AddTemplateParameterList(D->getTemplateParameters());
1617   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1618 
1619   VisitVarTemplateSpecializationDecl(D);
1620 
1621   // These are read/set from/to the first declaration.
1622   if (D->getPreviousDecl() == nullptr) {
1623     Record.AddDeclRef(D->getInstantiatedFromMember());
1624     Record.push_back(D->isMemberSpecialization());
1625   }
1626 
1627   Code = serialization::DECL_VAR_TEMPLATE_PARTIAL_SPECIALIZATION;
1628 }
1629 
1630 void ASTDeclWriter::VisitClassScopeFunctionSpecializationDecl(
1631                                     ClassScopeFunctionSpecializationDecl *D) {
1632   VisitDecl(D);
1633   Record.AddDeclRef(D->getSpecialization());
1634   Record.push_back(D->hasExplicitTemplateArgs());
1635   if (D->hasExplicitTemplateArgs())
1636     Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1637   Code = serialization::DECL_CLASS_SCOPE_FUNCTION_SPECIALIZATION;
1638 }
1639 
1640 
1641 void ASTDeclWriter::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
1642   VisitRedeclarableTemplateDecl(D);
1643 
1644   if (D->isFirstDecl())
1645     AddTemplateSpecializations(D);
1646   Code = serialization::DECL_FUNCTION_TEMPLATE;
1647 }
1648 
1649 void ASTDeclWriter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
1650   Record.push_back(D->hasTypeConstraint());
1651   VisitTypeDecl(D);
1652 
1653   Record.push_back(D->wasDeclaredWithTypename());
1654 
1655   const TypeConstraint *TC = D->getTypeConstraint();
1656   Record.push_back(TC != nullptr);
1657   if (TC) {
1658     Record.AddNestedNameSpecifierLoc(TC->getNestedNameSpecifierLoc());
1659     Record.AddDeclarationNameInfo(TC->getConceptNameInfo());
1660     Record.AddDeclRef(TC->getNamedConcept());
1661     Record.push_back(TC->getTemplateArgsAsWritten() != nullptr);
1662     if (TC->getTemplateArgsAsWritten())
1663       Record.AddASTTemplateArgumentListInfo(TC->getTemplateArgsAsWritten());
1664     Record.AddStmt(TC->getImmediatelyDeclaredConstraint());
1665     Record.push_back(D->isExpandedParameterPack());
1666     if (D->isExpandedParameterPack())
1667       Record.push_back(D->getNumExpansionParameters());
1668   }
1669 
1670   bool OwnsDefaultArg = D->hasDefaultArgument() &&
1671                         !D->defaultArgumentWasInherited();
1672   Record.push_back(OwnsDefaultArg);
1673   if (OwnsDefaultArg)
1674     Record.AddTypeSourceInfo(D->getDefaultArgumentInfo());
1675 
1676   Code = serialization::DECL_TEMPLATE_TYPE_PARM;
1677 }
1678 
1679 void ASTDeclWriter::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
1680   // For an expanded parameter pack, record the number of expansion types here
1681   // so that it's easier for deserialization to allocate the right amount of
1682   // memory.
1683   Expr *TypeConstraint = D->getPlaceholderTypeConstraint();
1684   Record.push_back(!!TypeConstraint);
1685   if (D->isExpandedParameterPack())
1686     Record.push_back(D->getNumExpansionTypes());
1687 
1688   VisitDeclaratorDecl(D);
1689   // TemplateParmPosition.
1690   Record.push_back(D->getDepth());
1691   Record.push_back(D->getPosition());
1692   if (TypeConstraint)
1693     Record.AddStmt(TypeConstraint);
1694 
1695   if (D->isExpandedParameterPack()) {
1696     for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1697       Record.AddTypeRef(D->getExpansionType(I));
1698       Record.AddTypeSourceInfo(D->getExpansionTypeSourceInfo(I));
1699     }
1700 
1701     Code = serialization::DECL_EXPANDED_NON_TYPE_TEMPLATE_PARM_PACK;
1702   } else {
1703     // Rest of NonTypeTemplateParmDecl.
1704     Record.push_back(D->isParameterPack());
1705     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1706                           !D->defaultArgumentWasInherited();
1707     Record.push_back(OwnsDefaultArg);
1708     if (OwnsDefaultArg)
1709       Record.AddStmt(D->getDefaultArgument());
1710     Code = serialization::DECL_NON_TYPE_TEMPLATE_PARM;
1711   }
1712 }
1713 
1714 void ASTDeclWriter::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
1715   // For an expanded parameter pack, record the number of expansion types here
1716   // so that it's easier for deserialization to allocate the right amount of
1717   // memory.
1718   if (D->isExpandedParameterPack())
1719     Record.push_back(D->getNumExpansionTemplateParameters());
1720 
1721   VisitTemplateDecl(D);
1722   // TemplateParmPosition.
1723   Record.push_back(D->getDepth());
1724   Record.push_back(D->getPosition());
1725 
1726   if (D->isExpandedParameterPack()) {
1727     for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
1728          I != N; ++I)
1729       Record.AddTemplateParameterList(D->getExpansionTemplateParameters(I));
1730     Code = serialization::DECL_EXPANDED_TEMPLATE_TEMPLATE_PARM_PACK;
1731   } else {
1732     // Rest of TemplateTemplateParmDecl.
1733     Record.push_back(D->isParameterPack());
1734     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1735                           !D->defaultArgumentWasInherited();
1736     Record.push_back(OwnsDefaultArg);
1737     if (OwnsDefaultArg)
1738       Record.AddTemplateArgumentLoc(D->getDefaultArgument());
1739     Code = serialization::DECL_TEMPLATE_TEMPLATE_PARM;
1740   }
1741 }
1742 
1743 void ASTDeclWriter::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
1744   VisitRedeclarableTemplateDecl(D);
1745   Code = serialization::DECL_TYPE_ALIAS_TEMPLATE;
1746 }
1747 
1748 void ASTDeclWriter::VisitStaticAssertDecl(StaticAssertDecl *D) {
1749   VisitDecl(D);
1750   Record.AddStmt(D->getAssertExpr());
1751   Record.push_back(D->isFailed());
1752   Record.AddStmt(D->getMessage());
1753   Record.AddSourceLocation(D->getRParenLoc());
1754   Code = serialization::DECL_STATIC_ASSERT;
1755 }
1756 
1757 /// Emit the DeclContext part of a declaration context decl.
1758 void ASTDeclWriter::VisitDeclContext(DeclContext *DC) {
1759   Record.AddOffset(Writer.WriteDeclContextLexicalBlock(Context, DC));
1760   Record.AddOffset(Writer.WriteDeclContextVisibleBlock(Context, DC));
1761 }
1762 
1763 const Decl *ASTWriter::getFirstLocalDecl(const Decl *D) {
1764   assert(IsLocalDecl(D) && "expected a local declaration");
1765 
1766   const Decl *Canon = D->getCanonicalDecl();
1767   if (IsLocalDecl(Canon))
1768     return Canon;
1769 
1770   const Decl *&CacheEntry = FirstLocalDeclCache[Canon];
1771   if (CacheEntry)
1772     return CacheEntry;
1773 
1774   for (const Decl *Redecl = D; Redecl; Redecl = Redecl->getPreviousDecl())
1775     if (IsLocalDecl(Redecl))
1776       D = Redecl;
1777   return CacheEntry = D;
1778 }
1779 
1780 template <typename T>
1781 void ASTDeclWriter::VisitRedeclarable(Redeclarable<T> *D) {
1782   T *First = D->getFirstDecl();
1783   T *MostRecent = First->getMostRecentDecl();
1784   T *DAsT = static_cast<T *>(D);
1785   if (MostRecent != First) {
1786     assert(isRedeclarableDeclKind(DAsT->getKind()) &&
1787            "Not considered redeclarable?");
1788 
1789     Record.AddDeclRef(First);
1790 
1791     // Write out a list of local redeclarations of this declaration if it's the
1792     // first local declaration in the chain.
1793     const Decl *FirstLocal = Writer.getFirstLocalDecl(DAsT);
1794     if (DAsT == FirstLocal) {
1795       // Emit a list of all imported first declarations so that we can be sure
1796       // that all redeclarations visible to this module are before D in the
1797       // redecl chain.
1798       unsigned I = Record.size();
1799       Record.push_back(0);
1800       if (Writer.Chain)
1801         AddFirstDeclFromEachModule(DAsT, /*IncludeLocal*/false);
1802       // This is the number of imported first declarations + 1.
1803       Record[I] = Record.size() - I;
1804 
1805       // Collect the set of local redeclarations of this declaration, from
1806       // newest to oldest.
1807       ASTWriter::RecordData LocalRedecls;
1808       ASTRecordWriter LocalRedeclWriter(Record, LocalRedecls);
1809       for (const Decl *Prev = FirstLocal->getMostRecentDecl();
1810            Prev != FirstLocal; Prev = Prev->getPreviousDecl())
1811         if (!Prev->isFromASTFile())
1812           LocalRedeclWriter.AddDeclRef(Prev);
1813 
1814       // If we have any redecls, write them now as a separate record preceding
1815       // the declaration itself.
1816       if (LocalRedecls.empty())
1817         Record.push_back(0);
1818       else
1819         Record.AddOffset(LocalRedeclWriter.Emit(LOCAL_REDECLARATIONS));
1820     } else {
1821       Record.push_back(0);
1822       Record.AddDeclRef(FirstLocal);
1823     }
1824 
1825     // Make sure that we serialize both the previous and the most-recent
1826     // declarations, which (transitively) ensures that all declarations in the
1827     // chain get serialized.
1828     //
1829     // FIXME: This is not correct; when we reach an imported declaration we
1830     // won't emit its previous declaration.
1831     (void)Writer.GetDeclRef(D->getPreviousDecl());
1832     (void)Writer.GetDeclRef(MostRecent);
1833   } else {
1834     // We use the sentinel value 0 to indicate an only declaration.
1835     Record.push_back(0);
1836   }
1837 }
1838 
1839 void ASTDeclWriter::VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D) {
1840   Record.writeOMPChildren(D->Data);
1841   VisitDecl(D);
1842   Code = serialization::DECL_OMP_THREADPRIVATE;
1843 }
1844 
1845 void ASTDeclWriter::VisitOMPAllocateDecl(OMPAllocateDecl *D) {
1846   Record.writeOMPChildren(D->Data);
1847   VisitDecl(D);
1848   Code = serialization::DECL_OMP_ALLOCATE;
1849 }
1850 
1851 void ASTDeclWriter::VisitOMPRequiresDecl(OMPRequiresDecl *D) {
1852   Record.writeOMPChildren(D->Data);
1853   VisitDecl(D);
1854   Code = serialization::DECL_OMP_REQUIRES;
1855 }
1856 
1857 void ASTDeclWriter::VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D) {
1858   VisitValueDecl(D);
1859   Record.AddSourceLocation(D->getBeginLoc());
1860   Record.AddStmt(D->getCombinerIn());
1861   Record.AddStmt(D->getCombinerOut());
1862   Record.AddStmt(D->getCombiner());
1863   Record.AddStmt(D->getInitOrig());
1864   Record.AddStmt(D->getInitPriv());
1865   Record.AddStmt(D->getInitializer());
1866   Record.push_back(D->getInitializerKind());
1867   Record.AddDeclRef(D->getPrevDeclInScope());
1868   Code = serialization::DECL_OMP_DECLARE_REDUCTION;
1869 }
1870 
1871 void ASTDeclWriter::VisitOMPDeclareMapperDecl(OMPDeclareMapperDecl *D) {
1872   Record.writeOMPChildren(D->Data);
1873   VisitValueDecl(D);
1874   Record.AddDeclarationName(D->getVarName());
1875   Record.AddDeclRef(D->getPrevDeclInScope());
1876   Code = serialization::DECL_OMP_DECLARE_MAPPER;
1877 }
1878 
1879 void ASTDeclWriter::VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D) {
1880   VisitVarDecl(D);
1881   Code = serialization::DECL_OMP_CAPTUREDEXPR;
1882 }
1883 
1884 //===----------------------------------------------------------------------===//
1885 // ASTWriter Implementation
1886 //===----------------------------------------------------------------------===//
1887 
1888 void ASTWriter::WriteDeclAbbrevs() {
1889   using namespace llvm;
1890 
1891   std::shared_ptr<BitCodeAbbrev> Abv;
1892 
1893   // Abbreviation for DECL_FIELD
1894   Abv = std::make_shared<BitCodeAbbrev>();
1895   Abv->Add(BitCodeAbbrevOp(serialization::DECL_FIELD));
1896   // Decl
1897   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1898   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1899   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1900   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1901   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1902   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1903   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1904   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1905   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1906   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1907   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1908   // NamedDecl
1909   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1910   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1911   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1912   // ValueDecl
1913   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1914   // DeclaratorDecl
1915   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1916   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1917   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
1918   // FieldDecl
1919   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1920   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
1921   // Type Source Info
1922   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1923   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1924   DeclFieldAbbrev = Stream.EmitAbbrev(std::move(Abv));
1925 
1926   // Abbreviation for DECL_OBJC_IVAR
1927   Abv = std::make_shared<BitCodeAbbrev>();
1928   Abv->Add(BitCodeAbbrevOp(serialization::DECL_OBJC_IVAR));
1929   // Decl
1930   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1931   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1932   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1933   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1934   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1935   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1936   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1937   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1938   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1939   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1940   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1941   // NamedDecl
1942   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1943   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1944   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1945   // ValueDecl
1946   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1947   // DeclaratorDecl
1948   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1949   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1950   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
1951   // FieldDecl
1952   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1953   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
1954   // ObjC Ivar
1955   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getAccessControl
1956   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getSynthesize
1957   // Type Source Info
1958   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1959   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1960   DeclObjCIvarAbbrev = Stream.EmitAbbrev(std::move(Abv));
1961 
1962   // Abbreviation for DECL_ENUM
1963   Abv = std::make_shared<BitCodeAbbrev>();
1964   Abv->Add(BitCodeAbbrevOp(serialization::DECL_ENUM));
1965   // Redeclarable
1966   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1967   // Decl
1968   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1969   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1970   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1971   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1972   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1973   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1974   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1975   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1976   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1977   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1978   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1979   // NamedDecl
1980   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1981   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1982   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1983   // TypeDecl
1984   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1985   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1986   // TagDecl
1987   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
1988   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
1989   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
1990   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
1991   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
1992   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
1993   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1994   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1995   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
1996   // EnumDecl
1997   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddTypeRef
1998   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IntegerType
1999   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getPromotionType
2000   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumPositiveBits
2001   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumNegativeBits
2002   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScoped
2003   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScopedUsingClassTag
2004   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isFixed
2005   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));// ODRHash
2006   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InstantiatedMembEnum
2007   // DC
2008   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
2009   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
2010   DeclEnumAbbrev = Stream.EmitAbbrev(std::move(Abv));
2011 
2012   // Abbreviation for DECL_RECORD
2013   Abv = std::make_shared<BitCodeAbbrev>();
2014   Abv->Add(BitCodeAbbrevOp(serialization::DECL_RECORD));
2015   // Redeclarable
2016   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2017   // Decl
2018   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2019   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2020   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2021   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2022   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2023   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2024   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2025   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2026   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2027   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2028   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2029   // NamedDecl
2030   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2031   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2032   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2033   // TypeDecl
2034   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
2035   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
2036   // TagDecl
2037   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
2038   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
2039   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
2040   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
2041   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
2042   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
2043   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2044   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2045   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
2046   // RecordDecl
2047   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // FlexibleArrayMember
2048   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // AnonymousStructUnion
2049   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasObjectMember
2050   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasVolatileMember
2051 
2052   // isNonTrivialToPrimitiveDefaultInitialize
2053   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2054   // isNonTrivialToPrimitiveCopy
2055   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2056   // isNonTrivialToPrimitiveDestroy
2057   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2058   // hasNonTrivialToPrimitiveDefaultInitializeCUnion
2059   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2060   // hasNonTrivialToPrimitiveDestructCUnion
2061   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2062   // hasNonTrivialToPrimitiveCopyCUnion
2063   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2064   // isParamDestroyedInCallee
2065   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2066   // getArgPassingRestrictions
2067   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));
2068 
2069   // DC
2070   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
2071   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
2072   DeclRecordAbbrev = Stream.EmitAbbrev(std::move(Abv));
2073 
2074   // Abbreviation for DECL_PARM_VAR
2075   Abv = std::make_shared<BitCodeAbbrev>();
2076   Abv->Add(BitCodeAbbrevOp(serialization::DECL_PARM_VAR));
2077   // Redeclarable
2078   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2079   // Decl
2080   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2081   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2082   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2083   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2084   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2085   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2086   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2087   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2088   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2089   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2090   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2091   // NamedDecl
2092   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2093   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2094   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2095   // ValueDecl
2096   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2097   // DeclaratorDecl
2098   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
2099   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
2100   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
2101   // VarDecl
2102   Abv->Add(BitCodeAbbrevOp(0));                       // SClass
2103   Abv->Add(BitCodeAbbrevOp(0));                       // TSCSpec
2104   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
2105   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isARCPseudoStrong
2106   Abv->Add(BitCodeAbbrevOp(0));                       // Linkage
2107   Abv->Add(BitCodeAbbrevOp(0));                       // HasInit
2108   Abv->Add(BitCodeAbbrevOp(0));                   // HasMemberSpecializationInfo
2109   // ParmVarDecl
2110   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsObjCMethodParameter
2111   Abv->Add(BitCodeAbbrevOp(0));                       // ScopeDepth
2112   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ScopeIndex
2113   Abv->Add(BitCodeAbbrevOp(0));                       // ObjCDeclQualifier
2114   Abv->Add(BitCodeAbbrevOp(0));                       // KNRPromoted
2115   Abv->Add(BitCodeAbbrevOp(0));                       // HasInheritedDefaultArg
2116   Abv->Add(BitCodeAbbrevOp(0));                   // HasUninstantiatedDefaultArg
2117   // Type Source Info
2118   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2119   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2120   DeclParmVarAbbrev = Stream.EmitAbbrev(std::move(Abv));
2121 
2122   // Abbreviation for DECL_TYPEDEF
2123   Abv = std::make_shared<BitCodeAbbrev>();
2124   Abv->Add(BitCodeAbbrevOp(serialization::DECL_TYPEDEF));
2125   // Redeclarable
2126   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2127   // Decl
2128   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2129   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2130   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2131   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2132   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2133   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isUsed
2134   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isReferenced
2135   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2136   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // C++ AccessSpecifier
2137   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2138   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2139   // NamedDecl
2140   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2141   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2142   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2143   // TypeDecl
2144   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
2145   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
2146   // TypedefDecl
2147   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2148   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2149   DeclTypedefAbbrev = Stream.EmitAbbrev(std::move(Abv));
2150 
2151   // Abbreviation for DECL_VAR
2152   Abv = std::make_shared<BitCodeAbbrev>();
2153   Abv->Add(BitCodeAbbrevOp(serialization::DECL_VAR));
2154   // Redeclarable
2155   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2156   // Decl
2157   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2158   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2159   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2160   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2161   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2162   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2163   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2164   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2165   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2166   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2167   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2168   // NamedDecl
2169   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2170   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2171   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2172   // ValueDecl
2173   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2174   // DeclaratorDecl
2175   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
2176   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
2177   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
2178   // VarDecl
2179   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // SClass
2180   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // TSCSpec
2181   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // InitStyle
2182   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isARCPseudoStrong
2183   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsThisDeclarationADemotedDefinition
2184   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isExceptionVariable
2185   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isNRVOVariable
2186   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCXXForRangeDecl
2187   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isObjCForDecl
2188   Abv->Add(BitCodeAbbrevOp(0));                         // isInline
2189   Abv->Add(BitCodeAbbrevOp(0));                         // isInlineSpecified
2190   Abv->Add(BitCodeAbbrevOp(0));                         // isConstexpr
2191   Abv->Add(BitCodeAbbrevOp(0));                         // isInitCapture
2192   Abv->Add(BitCodeAbbrevOp(0));                         // isPrevDeclInSameScope
2193   Abv->Add(BitCodeAbbrevOp(0));                         // ImplicitParamKind
2194   Abv->Add(BitCodeAbbrevOp(0));                         // EscapingByref
2195   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
2196   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // HasConstant*
2197   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // VarKind (local enum)
2198   // Type Source Info
2199   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2200   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2201   DeclVarAbbrev = Stream.EmitAbbrev(std::move(Abv));
2202 
2203   // Abbreviation for DECL_CXX_METHOD
2204   Abv = std::make_shared<BitCodeAbbrev>();
2205   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CXX_METHOD));
2206   // RedeclarableDecl
2207   Abv->Add(BitCodeAbbrevOp(0));                         // CanonicalDecl
2208   // Decl
2209   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // DeclContext
2210   Abv->Add(BitCodeAbbrevOp(0));                         // LexicalDeclContext
2211   Abv->Add(BitCodeAbbrevOp(0));                         // Invalid
2212   Abv->Add(BitCodeAbbrevOp(0));                         // HasAttrs
2213   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Implicit
2214   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Used
2215   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Referenced
2216   Abv->Add(BitCodeAbbrevOp(0));                         // InObjCContainer
2217   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // Access
2218   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ModulePrivate
2219   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SubmoduleID
2220   // NamedDecl
2221   Abv->Add(BitCodeAbbrevOp(DeclarationName::Identifier)); // NameKind
2222   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Identifier
2223   Abv->Add(BitCodeAbbrevOp(0));                         // AnonDeclNumber
2224   // ValueDecl
2225   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Type
2226   // DeclaratorDecl
2227   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InnerLocStart
2228   Abv->Add(BitCodeAbbrevOp(0));                         // HasExtInfo
2229   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // TSIType
2230   // FunctionDecl
2231   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 11)); // IDNS
2232   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // StorageClass
2233   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Inline
2234   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // InlineSpecified
2235   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // VirtualAsWritten
2236   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Pure
2237   Abv->Add(BitCodeAbbrevOp(0));                         // HasInheritedProto
2238   Abv->Add(BitCodeAbbrevOp(1));                         // HasWrittenProto
2239   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Deleted
2240   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Trivial
2241   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // TrivialForCall
2242   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Defaulted
2243   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ExplicitlyDefaulted
2244   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ImplicitReturnZero
2245   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Constexpr
2246   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // UsesSEHTry
2247   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // SkippedBody
2248   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // MultiVersion
2249   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // LateParsed
2250   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
2251   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LocEnd
2252   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32)); // ODRHash
2253   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // TemplateKind
2254   // This Array slurps the rest of the record. Fortunately we want to encode
2255   // (nearly) all the remaining (variable number of) fields in the same way.
2256   //
2257   // This is the function template information if any, then
2258   //         NumParams and Params[] from FunctionDecl, and
2259   //         NumOverriddenMethods, OverriddenMethods[] from CXXMethodDecl.
2260   //
2261   //  Add an AbbrevOp for 'size then elements' and use it here.
2262   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2263   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2264   DeclCXXMethodAbbrev = Stream.EmitAbbrev(std::move(Abv));
2265 
2266   // Abbreviation for EXPR_DECL_REF
2267   Abv = std::make_shared<BitCodeAbbrev>();
2268   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_DECL_REF));
2269   //Stmt
2270   // Expr
2271   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2272   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2273   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2274   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2275   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2276   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ContainsErrors
2277   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2278   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2279   //DeclRefExpr
2280   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HasQualifier
2281   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //GetDeclFound
2282   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ExplicitTemplateArgs
2283   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HadMultipleCandidates
2284   Abv->Add(BitCodeAbbrevOp(0)); // RefersToEnclosingVariableOrCapture
2285   Abv->Add(BitCodeAbbrevOp(0)); // NonOdrUseReason
2286   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclRef
2287   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2288   DeclRefExprAbbrev = Stream.EmitAbbrev(std::move(Abv));
2289 
2290   // Abbreviation for EXPR_INTEGER_LITERAL
2291   Abv = std::make_shared<BitCodeAbbrev>();
2292   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_INTEGER_LITERAL));
2293   //Stmt
2294   // Expr
2295   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2296   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2297   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2298   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2299   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2300   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ContainsErrors
2301   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2302   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2303   //Integer Literal
2304   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2305   Abv->Add(BitCodeAbbrevOp(32));                      // Bit Width
2306   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Value
2307   IntegerLiteralAbbrev = Stream.EmitAbbrev(std::move(Abv));
2308 
2309   // Abbreviation for EXPR_CHARACTER_LITERAL
2310   Abv = std::make_shared<BitCodeAbbrev>();
2311   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_CHARACTER_LITERAL));
2312   //Stmt
2313   // Expr
2314   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2315   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2316   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2317   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2318   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2319   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ContainsErrors
2320   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2321   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2322   //Character Literal
2323   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getValue
2324   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2325   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // getKind
2326   CharacterLiteralAbbrev = Stream.EmitAbbrev(std::move(Abv));
2327 
2328   // Abbreviation for EXPR_IMPLICIT_CAST
2329   Abv = std::make_shared<BitCodeAbbrev>();
2330   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_IMPLICIT_CAST));
2331   // Stmt
2332   // Expr
2333   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2334   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2335   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2336   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2337   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2338   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ContainsErrors
2339   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2340   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2341   // CastExpr
2342   Abv->Add(BitCodeAbbrevOp(0)); // PathSize
2343   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // HasFPFeatures
2344   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 6)); // CastKind
2345   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // PartOfExplicitCast
2346   // ImplicitCastExpr
2347   ExprImplicitCastAbbrev = Stream.EmitAbbrev(std::move(Abv));
2348 
2349   Abv = std::make_shared<BitCodeAbbrev>();
2350   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_LEXICAL));
2351   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2352   DeclContextLexicalAbbrev = Stream.EmitAbbrev(std::move(Abv));
2353 
2354   Abv = std::make_shared<BitCodeAbbrev>();
2355   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_VISIBLE));
2356   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2357   DeclContextVisibleLookupAbbrev = Stream.EmitAbbrev(std::move(Abv));
2358 }
2359 
2360 /// isRequiredDecl - Check if this is a "required" Decl, which must be seen by
2361 /// consumers of the AST.
2362 ///
2363 /// Such decls will always be deserialized from the AST file, so we would like
2364 /// this to be as restrictive as possible. Currently the predicate is driven by
2365 /// code generation requirements, if other clients have a different notion of
2366 /// what is "required" then we may have to consider an alternate scheme where
2367 /// clients can iterate over the top-level decls and get information on them,
2368 /// without necessary deserializing them. We could explicitly require such
2369 /// clients to use a separate API call to "realize" the decl. This should be
2370 /// relatively painless since they would presumably only do it for top-level
2371 /// decls.
2372 static bool isRequiredDecl(const Decl *D, ASTContext &Context,
2373                            bool WritingModule) {
2374   // An ObjCMethodDecl is never considered as "required" because its
2375   // implementation container always is.
2376 
2377   // File scoped assembly or obj-c or OMP declare target implementation must be
2378   // seen.
2379   if (isa<FileScopeAsmDecl>(D) || isa<ObjCImplDecl>(D))
2380     return true;
2381 
2382   if (WritingModule && isPartOfPerModuleInitializer(D)) {
2383     // These declarations are part of the module initializer, and are emitted
2384     // if and when the module is imported, rather than being emitted eagerly.
2385     return false;
2386   }
2387 
2388   return Context.DeclMustBeEmitted(D);
2389 }
2390 
2391 void ASTWriter::WriteDecl(ASTContext &Context, Decl *D) {
2392   PrettyDeclStackTraceEntry CrashInfo(Context, D, SourceLocation(),
2393                                       "serializing");
2394 
2395   // Determine the ID for this declaration.
2396   serialization::DeclID ID;
2397   assert(!D->isFromASTFile() && "should not be emitting imported decl");
2398   serialization::DeclID &IDR = DeclIDs[D];
2399   if (IDR == 0)
2400     IDR = NextDeclID++;
2401 
2402   ID = IDR;
2403 
2404   assert(ID >= FirstDeclID && "invalid decl ID");
2405 
2406   RecordData Record;
2407   ASTDeclWriter W(*this, Context, Record);
2408 
2409   // Build a record for this declaration
2410   W.Visit(D);
2411 
2412   // Emit this declaration to the bitstream.
2413   uint64_t Offset = W.Emit(D);
2414 
2415   // Record the offset for this declaration
2416   SourceLocation Loc = D->getLocation();
2417   unsigned Index = ID - FirstDeclID;
2418   if (DeclOffsets.size() == Index)
2419     DeclOffsets.emplace_back(Loc, Offset, DeclTypesBlockStartOffset);
2420   else if (DeclOffsets.size() < Index) {
2421     // FIXME: Can/should this happen?
2422     DeclOffsets.resize(Index+1);
2423     DeclOffsets[Index].setLocation(Loc);
2424     DeclOffsets[Index].setBitOffset(Offset, DeclTypesBlockStartOffset);
2425   } else {
2426     llvm_unreachable("declarations should be emitted in ID order");
2427   }
2428 
2429   SourceManager &SM = Context.getSourceManager();
2430   if (Loc.isValid() && SM.isLocalSourceLocation(Loc))
2431     associateDeclWithFile(D, ID);
2432 
2433   // Note declarations that should be deserialized eagerly so that we can add
2434   // them to a record in the AST file later.
2435   if (isRequiredDecl(D, Context, WritingModule))
2436     EagerlyDeserializedDecls.push_back(ID);
2437 }
2438 
2439 void ASTRecordWriter::AddFunctionDefinition(const FunctionDecl *FD) {
2440   // Switch case IDs are per function body.
2441   Writer->ClearSwitchCaseIDs();
2442 
2443   assert(FD->doesThisDeclarationHaveABody());
2444   bool ModulesCodegen = false;
2445   if (!FD->isDependentContext()) {
2446     Optional<GVALinkage> Linkage;
2447     if (Writer->WritingModule &&
2448         Writer->WritingModule->Kind == Module::ModuleInterfaceUnit) {
2449       // When building a C++ Modules TS module interface unit, a strong
2450       // definition in the module interface is provided by the compilation of
2451       // that module interface unit, not by its users. (Inline functions are
2452       // still emitted in module users.)
2453       Linkage = Writer->Context->GetGVALinkageForFunction(FD);
2454       ModulesCodegen = *Linkage == GVA_StrongExternal;
2455     }
2456     if (Writer->Context->getLangOpts().ModulesCodegen ||
2457         (FD->hasAttr<DLLExportAttr>() &&
2458          Writer->Context->getLangOpts().BuildingPCHWithObjectFile)) {
2459 
2460       // Under -fmodules-codegen, codegen is performed for all non-internal,
2461       // non-always_inline functions, unless they are available elsewhere.
2462       if (!FD->hasAttr<AlwaysInlineAttr>()) {
2463         if (!Linkage)
2464           Linkage = Writer->Context->GetGVALinkageForFunction(FD);
2465         ModulesCodegen =
2466             *Linkage != GVA_Internal && *Linkage != GVA_AvailableExternally;
2467       }
2468     }
2469   }
2470   Record->push_back(ModulesCodegen);
2471   if (ModulesCodegen)
2472     Writer->ModularCodegenDecls.push_back(Writer->GetDeclRef(FD));
2473   if (auto *CD = dyn_cast<CXXConstructorDecl>(FD)) {
2474     Record->push_back(CD->getNumCtorInitializers());
2475     if (CD->getNumCtorInitializers())
2476       AddCXXCtorInitializers(
2477           llvm::makeArrayRef(CD->init_begin(), CD->init_end()));
2478   }
2479   AddStmt(FD->getBody());
2480 }
2481