xref: /freebsd/contrib/llvm-project/clang/lib/Serialization/ASTWriterDecl.cpp (revision 732a02b4e77866604a120a275c082bb6221bd2ff) 
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 VisitIndirectFieldDecl(IndirectFieldDecl *D);
99     void VisitVarDecl(VarDecl *D);
100     void VisitImplicitParamDecl(ImplicitParamDecl *D);
101     void VisitParmVarDecl(ParmVarDecl *D);
102     void VisitDecompositionDecl(DecompositionDecl *D);
103     void VisitBindingDecl(BindingDecl *D);
104     void VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
105     void VisitTemplateDecl(TemplateDecl *D);
106     void VisitConceptDecl(ConceptDecl *D);
107     void VisitRequiresExprBodyDecl(RequiresExprBodyDecl *D);
108     void VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D);
109     void VisitClassTemplateDecl(ClassTemplateDecl *D);
110     void VisitVarTemplateDecl(VarTemplateDecl *D);
111     void VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
112     void VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
113     void VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D);
114     void VisitUsingDecl(UsingDecl *D);
115     void VisitUsingPackDecl(UsingPackDecl *D);
116     void VisitUsingShadowDecl(UsingShadowDecl *D);
117     void VisitConstructorUsingShadowDecl(ConstructorUsingShadowDecl *D);
118     void VisitLinkageSpecDecl(LinkageSpecDecl *D);
119     void VisitExportDecl(ExportDecl *D);
120     void VisitFileScopeAsmDecl(FileScopeAsmDecl *D);
121     void VisitImportDecl(ImportDecl *D);
122     void VisitAccessSpecDecl(AccessSpecDecl *D);
123     void VisitFriendDecl(FriendDecl *D);
124     void VisitFriendTemplateDecl(FriendTemplateDecl *D);
125     void VisitStaticAssertDecl(StaticAssertDecl *D);
126     void VisitBlockDecl(BlockDecl *D);
127     void VisitCapturedDecl(CapturedDecl *D);
128     void VisitEmptyDecl(EmptyDecl *D);
129     void VisitLifetimeExtendedTemporaryDecl(LifetimeExtendedTemporaryDecl *D);
130 
131     void VisitDeclContext(DeclContext *DC);
132     template <typename T> void VisitRedeclarable(Redeclarable<T> *D);
133 
134 
135     // FIXME: Put in the same order is DeclNodes.td?
136     void VisitObjCMethodDecl(ObjCMethodDecl *D);
137     void VisitObjCTypeParamDecl(ObjCTypeParamDecl *D);
138     void VisitObjCContainerDecl(ObjCContainerDecl *D);
139     void VisitObjCInterfaceDecl(ObjCInterfaceDecl *D);
140     void VisitObjCIvarDecl(ObjCIvarDecl *D);
141     void VisitObjCProtocolDecl(ObjCProtocolDecl *D);
142     void VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D);
143     void VisitObjCCategoryDecl(ObjCCategoryDecl *D);
144     void VisitObjCImplDecl(ObjCImplDecl *D);
145     void VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D);
146     void VisitObjCImplementationDecl(ObjCImplementationDecl *D);
147     void VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D);
148     void VisitObjCPropertyDecl(ObjCPropertyDecl *D);
149     void VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D);
150     void VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D);
151     void VisitOMPAllocateDecl(OMPAllocateDecl *D);
152     void VisitOMPRequiresDecl(OMPRequiresDecl *D);
153     void VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D);
154     void VisitOMPDeclareMapperDecl(OMPDeclareMapperDecl *D);
155     void VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D);
156 
157     /// Add an Objective-C type parameter list to the given record.
158     void AddObjCTypeParamList(ObjCTypeParamList *typeParams) {
159       // Empty type parameter list.
160       if (!typeParams) {
161         Record.push_back(0);
162         return;
163       }
164 
165       Record.push_back(typeParams->size());
166       for (auto typeParam : *typeParams) {
167         Record.AddDeclRef(typeParam);
168       }
169       Record.AddSourceLocation(typeParams->getLAngleLoc());
170       Record.AddSourceLocation(typeParams->getRAngleLoc());
171     }
172 
173     /// Add to the record the first declaration from each module file that
174     /// provides a declaration of D. The intent is to provide a sufficient
175     /// set such that reloading this set will load all current redeclarations.
176     void AddFirstDeclFromEachModule(const Decl *D, bool IncludeLocal) {
177       llvm::MapVector<ModuleFile*, const Decl*> Firsts;
178       // FIXME: We can skip entries that we know are implied by others.
179       for (const Decl *R = D->getMostRecentDecl(); R; R = R->getPreviousDecl()) {
180         if (R->isFromASTFile())
181           Firsts[Writer.Chain->getOwningModuleFile(R)] = R;
182         else if (IncludeLocal)
183           Firsts[nullptr] = R;
184       }
185       for (const auto &F : Firsts)
186         Record.AddDeclRef(F.second);
187     }
188 
189     /// Get the specialization decl from an entry in the specialization list.
190     template <typename EntryType>
191     typename RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::DeclType *
192     getSpecializationDecl(EntryType &T) {
193       return RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::getDecl(&T);
194     }
195 
196     /// Get the list of partial specializations from a template's common ptr.
197     template<typename T>
198     decltype(T::PartialSpecializations) &getPartialSpecializations(T *Common) {
199       return Common->PartialSpecializations;
200     }
201     ArrayRef<Decl> getPartialSpecializations(FunctionTemplateDecl::Common *) {
202       return None;
203     }
204 
205     template<typename DeclTy>
206     void AddTemplateSpecializations(DeclTy *D) {
207       auto *Common = D->getCommonPtr();
208 
209       // If we have any lazy specializations, and the external AST source is
210       // our chained AST reader, we can just write out the DeclIDs. Otherwise,
211       // we need to resolve them to actual declarations.
212       if (Writer.Chain != Writer.Context->getExternalSource() &&
213           Common->LazySpecializations) {
214         D->LoadLazySpecializations();
215         assert(!Common->LazySpecializations);
216       }
217 
218       ArrayRef<DeclID> LazySpecializations;
219       if (auto *LS = Common->LazySpecializations)
220         LazySpecializations = llvm::makeArrayRef(LS + 1, LS[0]);
221 
222       // Add a slot to the record for the number of specializations.
223       unsigned I = Record.size();
224       Record.push_back(0);
225 
226       // AddFirstDeclFromEachModule might trigger deserialization, invalidating
227       // *Specializations iterators.
228       llvm::SmallVector<const Decl*, 16> Specs;
229       for (auto &Entry : Common->Specializations)
230         Specs.push_back(getSpecializationDecl(Entry));
231       for (auto &Entry : getPartialSpecializations(Common))
232         Specs.push_back(getSpecializationDecl(Entry));
233 
234       for (auto *D : Specs) {
235         assert(D->isCanonicalDecl() && "non-canonical decl in set");
236         AddFirstDeclFromEachModule(D, /*IncludeLocal*/true);
237       }
238       Record.append(LazySpecializations.begin(), LazySpecializations.end());
239 
240       // Update the size entry we added earlier.
241       Record[I] = Record.size() - I - 1;
242     }
243 
244     /// Ensure that this template specialization is associated with the specified
245     /// template on reload.
246     void RegisterTemplateSpecialization(const Decl *Template,
247                                         const Decl *Specialization) {
248       Template = Template->getCanonicalDecl();
249 
250       // If the canonical template is local, we'll write out this specialization
251       // when we emit it.
252       // FIXME: We can do the same thing if there is any local declaration of
253       // the template, to avoid emitting an update record.
254       if (!Template->isFromASTFile())
255         return;
256 
257       // We only need to associate the first local declaration of the
258       // specialization. The other declarations will get pulled in by it.
259       if (Writer.getFirstLocalDecl(Specialization) != Specialization)
260         return;
261 
262       Writer.DeclUpdates[Template].push_back(ASTWriter::DeclUpdate(
263           UPD_CXX_ADDED_TEMPLATE_SPECIALIZATION, Specialization));
264     }
265   };
266 }
267 
268 void ASTDeclWriter::Visit(Decl *D) {
269   DeclVisitor<ASTDeclWriter>::Visit(D);
270 
271   // Source locations require array (variable-length) abbreviations.  The
272   // abbreviation infrastructure requires that arrays are encoded last, so
273   // we handle it here in the case of those classes derived from DeclaratorDecl
274   if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D)) {
275     if (auto *TInfo = DD->getTypeSourceInfo())
276       Record.AddTypeLoc(TInfo->getTypeLoc());
277   }
278 
279   // Handle FunctionDecl's body here and write it after all other Stmts/Exprs
280   // have been written. We want it last because we will not read it back when
281   // retrieving it from the AST, we'll just lazily set the offset.
282   if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
283     Record.push_back(FD->doesThisDeclarationHaveABody());
284     if (FD->doesThisDeclarationHaveABody())
285       Record.AddFunctionDefinition(FD);
286   }
287 
288   // If this declaration is also a DeclContext, write blocks for the
289   // declarations that lexically stored inside its context and those
290   // declarations that are visible from its context.
291   if (DeclContext *DC = dyn_cast<DeclContext>(D))
292     VisitDeclContext(DC);
293 }
294 
295 void ASTDeclWriter::VisitDecl(Decl *D) {
296   Record.AddDeclRef(cast_or_null<Decl>(D->getDeclContext()));
297   if (D->getDeclContext() != D->getLexicalDeclContext())
298     Record.AddDeclRef(cast_or_null<Decl>(D->getLexicalDeclContext()));
299   else
300     Record.push_back(0);
301   Record.push_back(D->isInvalidDecl());
302   Record.push_back(D->hasAttrs());
303   if (D->hasAttrs())
304     Record.AddAttributes(D->getAttrs());
305   Record.push_back(D->isImplicit());
306   Record.push_back(D->isUsed(false));
307   Record.push_back(D->isReferenced());
308   Record.push_back(D->isTopLevelDeclInObjCContainer());
309   Record.push_back(D->getAccess());
310   Record.push_back(D->isModulePrivate());
311   Record.push_back(Writer.getSubmoduleID(D->getOwningModule()));
312 
313   // If this declaration injected a name into a context different from its
314   // lexical context, and that context is an imported namespace, we need to
315   // update its visible declarations to include this name.
316   //
317   // This happens when we instantiate a class with a friend declaration or a
318   // function with a local extern declaration, for instance.
319   //
320   // FIXME: Can we handle this in AddedVisibleDecl instead?
321   if (D->isOutOfLine()) {
322     auto *DC = D->getDeclContext();
323     while (auto *NS = dyn_cast<NamespaceDecl>(DC->getRedeclContext())) {
324       if (!NS->isFromASTFile())
325         break;
326       Writer.UpdatedDeclContexts.insert(NS->getPrimaryContext());
327       if (!NS->isInlineNamespace())
328         break;
329       DC = NS->getParent();
330     }
331   }
332 }
333 
334 void ASTDeclWriter::VisitPragmaCommentDecl(PragmaCommentDecl *D) {
335   StringRef Arg = D->getArg();
336   Record.push_back(Arg.size());
337   VisitDecl(D);
338   Record.AddSourceLocation(D->getBeginLoc());
339   Record.push_back(D->getCommentKind());
340   Record.AddString(Arg);
341   Code = serialization::DECL_PRAGMA_COMMENT;
342 }
343 
344 void ASTDeclWriter::VisitPragmaDetectMismatchDecl(
345     PragmaDetectMismatchDecl *D) {
346   StringRef Name = D->getName();
347   StringRef Value = D->getValue();
348   Record.push_back(Name.size() + 1 + Value.size());
349   VisitDecl(D);
350   Record.AddSourceLocation(D->getBeginLoc());
351   Record.AddString(Name);
352   Record.AddString(Value);
353   Code = serialization::DECL_PRAGMA_DETECT_MISMATCH;
354 }
355 
356 void ASTDeclWriter::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
357   llvm_unreachable("Translation units aren't directly serialized");
358 }
359 
360 void ASTDeclWriter::VisitNamedDecl(NamedDecl *D) {
361   VisitDecl(D);
362   Record.AddDeclarationName(D->getDeclName());
363   Record.push_back(needsAnonymousDeclarationNumber(D)
364                        ? Writer.getAnonymousDeclarationNumber(D)
365                        : 0);
366 }
367 
368 void ASTDeclWriter::VisitTypeDecl(TypeDecl *D) {
369   VisitNamedDecl(D);
370   Record.AddSourceLocation(D->getBeginLoc());
371   Record.AddTypeRef(QualType(D->getTypeForDecl(), 0));
372 }
373 
374 void ASTDeclWriter::VisitTypedefNameDecl(TypedefNameDecl *D) {
375   VisitRedeclarable(D);
376   VisitTypeDecl(D);
377   Record.AddTypeSourceInfo(D->getTypeSourceInfo());
378   Record.push_back(D->isModed());
379   if (D->isModed())
380     Record.AddTypeRef(D->getUnderlyingType());
381   Record.AddDeclRef(D->getAnonDeclWithTypedefName(false));
382 }
383 
384 void ASTDeclWriter::VisitTypedefDecl(TypedefDecl *D) {
385   VisitTypedefNameDecl(D);
386   if (D->getDeclContext() == D->getLexicalDeclContext() &&
387       !D->hasAttrs() &&
388       !D->isImplicit() &&
389       D->getFirstDecl() == D->getMostRecentDecl() &&
390       !D->isInvalidDecl() &&
391       !D->isTopLevelDeclInObjCContainer() &&
392       !D->isModulePrivate() &&
393       !needsAnonymousDeclarationNumber(D) &&
394       D->getDeclName().getNameKind() == DeclarationName::Identifier)
395     AbbrevToUse = Writer.getDeclTypedefAbbrev();
396 
397   Code = serialization::DECL_TYPEDEF;
398 }
399 
400 void ASTDeclWriter::VisitTypeAliasDecl(TypeAliasDecl *D) {
401   VisitTypedefNameDecl(D);
402   Record.AddDeclRef(D->getDescribedAliasTemplate());
403   Code = serialization::DECL_TYPEALIAS;
404 }
405 
406 void ASTDeclWriter::VisitTagDecl(TagDecl *D) {
407   VisitRedeclarable(D);
408   VisitTypeDecl(D);
409   Record.push_back(D->getIdentifierNamespace());
410   Record.push_back((unsigned)D->getTagKind()); // FIXME: stable encoding
411   if (!isa<CXXRecordDecl>(D))
412     Record.push_back(D->isCompleteDefinition());
413   Record.push_back(D->isEmbeddedInDeclarator());
414   Record.push_back(D->isFreeStanding());
415   Record.push_back(D->isCompleteDefinitionRequired());
416   Record.AddSourceRange(D->getBraceRange());
417 
418   if (D->hasExtInfo()) {
419     Record.push_back(1);
420     Record.AddQualifierInfo(*D->getExtInfo());
421   } else if (auto *TD = D->getTypedefNameForAnonDecl()) {
422     Record.push_back(2);
423     Record.AddDeclRef(TD);
424     Record.AddIdentifierRef(TD->getDeclName().getAsIdentifierInfo());
425   } else {
426     Record.push_back(0);
427   }
428 }
429 
430 void ASTDeclWriter::VisitEnumDecl(EnumDecl *D) {
431   VisitTagDecl(D);
432   Record.AddTypeSourceInfo(D->getIntegerTypeSourceInfo());
433   if (!D->getIntegerTypeSourceInfo())
434     Record.AddTypeRef(D->getIntegerType());
435   Record.AddTypeRef(D->getPromotionType());
436   Record.push_back(D->getNumPositiveBits());
437   Record.push_back(D->getNumNegativeBits());
438   Record.push_back(D->isScoped());
439   Record.push_back(D->isScopedUsingClassTag());
440   Record.push_back(D->isFixed());
441   Record.push_back(D->getODRHash());
442 
443   if (MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo()) {
444     Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
445     Record.push_back(MemberInfo->getTemplateSpecializationKind());
446     Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
447   } else {
448     Record.AddDeclRef(nullptr);
449   }
450 
451   if (D->getDeclContext() == D->getLexicalDeclContext() &&
452       !D->hasAttrs() &&
453       !D->isImplicit() &&
454       !D->isUsed(false) &&
455       !D->hasExtInfo() &&
456       !D->getTypedefNameForAnonDecl() &&
457       D->getFirstDecl() == D->getMostRecentDecl() &&
458       !D->isInvalidDecl() &&
459       !D->isReferenced() &&
460       !D->isTopLevelDeclInObjCContainer() &&
461       D->getAccess() == AS_none &&
462       !D->isModulePrivate() &&
463       !CXXRecordDecl::classofKind(D->getKind()) &&
464       !D->getIntegerTypeSourceInfo() &&
465       !D->getMemberSpecializationInfo() &&
466       !needsAnonymousDeclarationNumber(D) &&
467       D->getDeclName().getNameKind() == DeclarationName::Identifier)
468     AbbrevToUse = Writer.getDeclEnumAbbrev();
469 
470   Code = serialization::DECL_ENUM;
471 }
472 
473 void ASTDeclWriter::VisitRecordDecl(RecordDecl *D) {
474   VisitTagDecl(D);
475   Record.push_back(D->hasFlexibleArrayMember());
476   Record.push_back(D->isAnonymousStructOrUnion());
477   Record.push_back(D->hasObjectMember());
478   Record.push_back(D->hasVolatileMember());
479   Record.push_back(D->isNonTrivialToPrimitiveDefaultInitialize());
480   Record.push_back(D->isNonTrivialToPrimitiveCopy());
481   Record.push_back(D->isNonTrivialToPrimitiveDestroy());
482   Record.push_back(D->hasNonTrivialToPrimitiveDefaultInitializeCUnion());
483   Record.push_back(D->hasNonTrivialToPrimitiveDestructCUnion());
484   Record.push_back(D->hasNonTrivialToPrimitiveCopyCUnion());
485   Record.push_back(D->isParamDestroyedInCallee());
486   Record.push_back(D->getArgPassingRestrictions());
487 
488   if (D->getDeclContext() == D->getLexicalDeclContext() &&
489       !D->hasAttrs() &&
490       !D->isImplicit() &&
491       !D->isUsed(false) &&
492       !D->hasExtInfo() &&
493       !D->getTypedefNameForAnonDecl() &&
494       D->getFirstDecl() == D->getMostRecentDecl() &&
495       !D->isInvalidDecl() &&
496       !D->isReferenced() &&
497       !D->isTopLevelDeclInObjCContainer() &&
498       D->getAccess() == AS_none &&
499       !D->isModulePrivate() &&
500       !CXXRecordDecl::classofKind(D->getKind()) &&
501       !needsAnonymousDeclarationNumber(D) &&
502       D->getDeclName().getNameKind() == DeclarationName::Identifier)
503     AbbrevToUse = Writer.getDeclRecordAbbrev();
504 
505   Code = serialization::DECL_RECORD;
506 }
507 
508 void ASTDeclWriter::VisitValueDecl(ValueDecl *D) {
509   VisitNamedDecl(D);
510   Record.AddTypeRef(D->getType());
511 }
512 
513 void ASTDeclWriter::VisitEnumConstantDecl(EnumConstantDecl *D) {
514   VisitValueDecl(D);
515   Record.push_back(D->getInitExpr()? 1 : 0);
516   if (D->getInitExpr())
517     Record.AddStmt(D->getInitExpr());
518   Record.AddAPSInt(D->getInitVal());
519 
520   Code = serialization::DECL_ENUM_CONSTANT;
521 }
522 
523 void ASTDeclWriter::VisitDeclaratorDecl(DeclaratorDecl *D) {
524   VisitValueDecl(D);
525   Record.AddSourceLocation(D->getInnerLocStart());
526   Record.push_back(D->hasExtInfo());
527   if (D->hasExtInfo()) {
528     DeclaratorDecl::ExtInfo *Info = D->getExtInfo();
529     Record.AddQualifierInfo(*Info);
530     Record.AddStmt(Info->TrailingRequiresClause);
531   }
532   // The location information is deferred until the end of the record.
533   Record.AddTypeRef(D->getTypeSourceInfo() ? D->getTypeSourceInfo()->getType()
534                                            : QualType());
535 }
536 
537 void ASTDeclWriter::VisitFunctionDecl(FunctionDecl *D) {
538   VisitRedeclarable(D);
539   VisitDeclaratorDecl(D);
540   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
541   Record.push_back(D->getIdentifierNamespace());
542 
543   // FunctionDecl's body is handled last at ASTWriterDecl::Visit,
544   // after everything else is written.
545   Record.push_back(static_cast<int>(D->getStorageClass())); // FIXME: stable encoding
546   Record.push_back(D->isInlineSpecified());
547   Record.push_back(D->isInlined());
548   Record.push_back(D->isVirtualAsWritten());
549   Record.push_back(D->isPure());
550   Record.push_back(D->hasInheritedPrototype());
551   Record.push_back(D->hasWrittenPrototype());
552   Record.push_back(D->isDeletedBit());
553   Record.push_back(D->isTrivial());
554   Record.push_back(D->isTrivialForCall());
555   Record.push_back(D->isDefaulted());
556   Record.push_back(D->isExplicitlyDefaulted());
557   Record.push_back(D->hasImplicitReturnZero());
558   Record.push_back(D->getConstexprKind());
559   Record.push_back(D->usesSEHTry());
560   Record.push_back(D->hasSkippedBody());
561   Record.push_back(D->isMultiVersion());
562   Record.push_back(D->isLateTemplateParsed());
563   Record.push_back(D->getLinkageInternal());
564   Record.AddSourceLocation(D->getEndLoc());
565 
566   Record.push_back(D->getODRHash());
567   Record.push_back(D->usesFPIntrin());
568 
569   if (D->isDefaulted()) {
570     if (auto *FDI = D->getDefaultedFunctionInfo()) {
571       Record.push_back(FDI->getUnqualifiedLookups().size());
572       for (DeclAccessPair P : FDI->getUnqualifiedLookups()) {
573         Record.AddDeclRef(P.getDecl());
574         Record.push_back(P.getAccess());
575       }
576     } else {
577       Record.push_back(0);
578     }
579   }
580 
581   Record.push_back(D->getTemplatedKind());
582   switch (D->getTemplatedKind()) {
583   case FunctionDecl::TK_NonTemplate:
584     break;
585   case FunctionDecl::TK_FunctionTemplate:
586     Record.AddDeclRef(D->getDescribedFunctionTemplate());
587     break;
588   case FunctionDecl::TK_MemberSpecialization: {
589     MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo();
590     Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
591     Record.push_back(MemberInfo->getTemplateSpecializationKind());
592     Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
593     break;
594   }
595   case FunctionDecl::TK_FunctionTemplateSpecialization: {
596     FunctionTemplateSpecializationInfo *
597       FTSInfo = D->getTemplateSpecializationInfo();
598 
599     RegisterTemplateSpecialization(FTSInfo->getTemplate(), D);
600 
601     Record.AddDeclRef(FTSInfo->getTemplate());
602     Record.push_back(FTSInfo->getTemplateSpecializationKind());
603 
604     // Template arguments.
605     Record.AddTemplateArgumentList(FTSInfo->TemplateArguments);
606 
607     // Template args as written.
608     Record.push_back(FTSInfo->TemplateArgumentsAsWritten != nullptr);
609     if (FTSInfo->TemplateArgumentsAsWritten) {
610       Record.push_back(FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs);
611       for (int i=0, e = FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs;
612              i!=e; ++i)
613         Record.AddTemplateArgumentLoc(
614             (*FTSInfo->TemplateArgumentsAsWritten)[i]);
615       Record.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->LAngleLoc);
616       Record.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->RAngleLoc);
617     }
618 
619     Record.AddSourceLocation(FTSInfo->getPointOfInstantiation());
620 
621     if (MemberSpecializationInfo *MemberInfo =
622         FTSInfo->getMemberSpecializationInfo()) {
623       Record.push_back(1);
624       Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
625       Record.push_back(MemberInfo->getTemplateSpecializationKind());
626       Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
627     } else {
628       Record.push_back(0);
629     }
630 
631     if (D->isCanonicalDecl()) {
632       // Write the template that contains the specializations set. We will
633       // add a FunctionTemplateSpecializationInfo to it when reading.
634       Record.AddDeclRef(FTSInfo->getTemplate()->getCanonicalDecl());
635     }
636     break;
637   }
638   case FunctionDecl::TK_DependentFunctionTemplateSpecialization: {
639     DependentFunctionTemplateSpecializationInfo *
640       DFTSInfo = D->getDependentSpecializationInfo();
641 
642     // Templates.
643     Record.push_back(DFTSInfo->getNumTemplates());
644     for (int i=0, e = DFTSInfo->getNumTemplates(); i != e; ++i)
645       Record.AddDeclRef(DFTSInfo->getTemplate(i));
646 
647     // Templates args.
648     Record.push_back(DFTSInfo->getNumTemplateArgs());
649     for (int i=0, e = DFTSInfo->getNumTemplateArgs(); i != e; ++i)
650       Record.AddTemplateArgumentLoc(DFTSInfo->getTemplateArg(i));
651     Record.AddSourceLocation(DFTSInfo->getLAngleLoc());
652     Record.AddSourceLocation(DFTSInfo->getRAngleLoc());
653     break;
654   }
655   }
656 
657   Record.push_back(D->param_size());
658   for (auto P : D->parameters())
659     Record.AddDeclRef(P);
660   Code = serialization::DECL_FUNCTION;
661 }
662 
663 static void addExplicitSpecifier(ExplicitSpecifier ES,
664                                  ASTRecordWriter &Record) {
665   uint64_t Kind = static_cast<uint64_t>(ES.getKind());
666   Kind = Kind << 1 | static_cast<bool>(ES.getExpr());
667   Record.push_back(Kind);
668   if (ES.getExpr()) {
669     Record.AddStmt(ES.getExpr());
670   }
671 }
672 
673 void ASTDeclWriter::VisitCXXDeductionGuideDecl(CXXDeductionGuideDecl *D) {
674   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
675   VisitFunctionDecl(D);
676   Record.push_back(D->isCopyDeductionCandidate());
677   Code = serialization::DECL_CXX_DEDUCTION_GUIDE;
678 }
679 
680 void ASTDeclWriter::VisitObjCMethodDecl(ObjCMethodDecl *D) {
681   VisitNamedDecl(D);
682   // FIXME: convert to LazyStmtPtr?
683   // Unlike C/C++, method bodies will never be in header files.
684   bool HasBodyStuff = D->getBody() != nullptr;
685   Record.push_back(HasBodyStuff);
686   if (HasBodyStuff) {
687     Record.AddStmt(D->getBody());
688   }
689   Record.AddDeclRef(D->getSelfDecl());
690   Record.AddDeclRef(D->getCmdDecl());
691   Record.push_back(D->isInstanceMethod());
692   Record.push_back(D->isVariadic());
693   Record.push_back(D->isPropertyAccessor());
694   Record.push_back(D->isSynthesizedAccessorStub());
695   Record.push_back(D->isDefined());
696   Record.push_back(D->isOverriding());
697   Record.push_back(D->hasSkippedBody());
698 
699   Record.push_back(D->isRedeclaration());
700   Record.push_back(D->hasRedeclaration());
701   if (D->hasRedeclaration()) {
702     assert(Context.getObjCMethodRedeclaration(D));
703     Record.AddDeclRef(Context.getObjCMethodRedeclaration(D));
704   }
705 
706   // FIXME: stable encoding for @required/@optional
707   Record.push_back(D->getImplementationControl());
708   // FIXME: stable encoding for in/out/inout/bycopy/byref/oneway/nullability
709   Record.push_back(D->getObjCDeclQualifier());
710   Record.push_back(D->hasRelatedResultType());
711   Record.AddTypeRef(D->getReturnType());
712   Record.AddTypeSourceInfo(D->getReturnTypeSourceInfo());
713   Record.AddSourceLocation(D->getEndLoc());
714   Record.push_back(D->param_size());
715   for (const auto *P : D->parameters())
716     Record.AddDeclRef(P);
717 
718   Record.push_back(D->getSelLocsKind());
719   unsigned NumStoredSelLocs = D->getNumStoredSelLocs();
720   SourceLocation *SelLocs = D->getStoredSelLocs();
721   Record.push_back(NumStoredSelLocs);
722   for (unsigned i = 0; i != NumStoredSelLocs; ++i)
723     Record.AddSourceLocation(SelLocs[i]);
724 
725   Code = serialization::DECL_OBJC_METHOD;
726 }
727 
728 void ASTDeclWriter::VisitObjCTypeParamDecl(ObjCTypeParamDecl *D) {
729   VisitTypedefNameDecl(D);
730   Record.push_back(D->Variance);
731   Record.push_back(D->Index);
732   Record.AddSourceLocation(D->VarianceLoc);
733   Record.AddSourceLocation(D->ColonLoc);
734 
735   Code = serialization::DECL_OBJC_TYPE_PARAM;
736 }
737 
738 void ASTDeclWriter::VisitObjCContainerDecl(ObjCContainerDecl *D) {
739   VisitNamedDecl(D);
740   Record.AddSourceLocation(D->getAtStartLoc());
741   Record.AddSourceRange(D->getAtEndRange());
742   // Abstract class (no need to define a stable serialization::DECL code).
743 }
744 
745 void ASTDeclWriter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
746   VisitRedeclarable(D);
747   VisitObjCContainerDecl(D);
748   Record.AddTypeRef(QualType(D->getTypeForDecl(), 0));
749   AddObjCTypeParamList(D->TypeParamList);
750 
751   Record.push_back(D->isThisDeclarationADefinition());
752   if (D->isThisDeclarationADefinition()) {
753     // Write the DefinitionData
754     ObjCInterfaceDecl::DefinitionData &Data = D->data();
755 
756     Record.AddTypeSourceInfo(D->getSuperClassTInfo());
757     Record.AddSourceLocation(D->getEndOfDefinitionLoc());
758     Record.push_back(Data.HasDesignatedInitializers);
759 
760     // Write out the protocols that are directly referenced by the @interface.
761     Record.push_back(Data.ReferencedProtocols.size());
762     for (const auto *P : D->protocols())
763       Record.AddDeclRef(P);
764     for (const auto &PL : D->protocol_locs())
765       Record.AddSourceLocation(PL);
766 
767     // Write out the protocols that are transitively referenced.
768     Record.push_back(Data.AllReferencedProtocols.size());
769     for (ObjCList<ObjCProtocolDecl>::iterator
770               P = Data.AllReferencedProtocols.begin(),
771            PEnd = Data.AllReferencedProtocols.end();
772          P != PEnd; ++P)
773       Record.AddDeclRef(*P);
774 
775 
776     if (ObjCCategoryDecl *Cat = D->getCategoryListRaw()) {
777       // Ensure that we write out the set of categories for this class.
778       Writer.ObjCClassesWithCategories.insert(D);
779 
780       // Make sure that the categories get serialized.
781       for (; Cat; Cat = Cat->getNextClassCategoryRaw())
782         (void)Writer.GetDeclRef(Cat);
783     }
784   }
785 
786   Code = serialization::DECL_OBJC_INTERFACE;
787 }
788 
789 void ASTDeclWriter::VisitObjCIvarDecl(ObjCIvarDecl *D) {
790   VisitFieldDecl(D);
791   // FIXME: stable encoding for @public/@private/@protected/@package
792   Record.push_back(D->getAccessControl());
793   Record.push_back(D->getSynthesize());
794 
795   if (D->getDeclContext() == D->getLexicalDeclContext() &&
796       !D->hasAttrs() &&
797       !D->isImplicit() &&
798       !D->isUsed(false) &&
799       !D->isInvalidDecl() &&
800       !D->isReferenced() &&
801       !D->isModulePrivate() &&
802       !D->getBitWidth() &&
803       !D->hasExtInfo() &&
804       D->getDeclName())
805     AbbrevToUse = Writer.getDeclObjCIvarAbbrev();
806 
807   Code = serialization::DECL_OBJC_IVAR;
808 }
809 
810 void ASTDeclWriter::VisitObjCProtocolDecl(ObjCProtocolDecl *D) {
811   VisitRedeclarable(D);
812   VisitObjCContainerDecl(D);
813 
814   Record.push_back(D->isThisDeclarationADefinition());
815   if (D->isThisDeclarationADefinition()) {
816     Record.push_back(D->protocol_size());
817     for (const auto *I : D->protocols())
818       Record.AddDeclRef(I);
819     for (const auto &PL : D->protocol_locs())
820       Record.AddSourceLocation(PL);
821   }
822 
823   Code = serialization::DECL_OBJC_PROTOCOL;
824 }
825 
826 void ASTDeclWriter::VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D) {
827   VisitFieldDecl(D);
828   Code = serialization::DECL_OBJC_AT_DEFS_FIELD;
829 }
830 
831 void ASTDeclWriter::VisitObjCCategoryDecl(ObjCCategoryDecl *D) {
832   VisitObjCContainerDecl(D);
833   Record.AddSourceLocation(D->getCategoryNameLoc());
834   Record.AddSourceLocation(D->getIvarLBraceLoc());
835   Record.AddSourceLocation(D->getIvarRBraceLoc());
836   Record.AddDeclRef(D->getClassInterface());
837   AddObjCTypeParamList(D->TypeParamList);
838   Record.push_back(D->protocol_size());
839   for (const auto *I : D->protocols())
840     Record.AddDeclRef(I);
841   for (const auto &PL : D->protocol_locs())
842     Record.AddSourceLocation(PL);
843   Code = serialization::DECL_OBJC_CATEGORY;
844 }
845 
846 void ASTDeclWriter::VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D) {
847   VisitNamedDecl(D);
848   Record.AddDeclRef(D->getClassInterface());
849   Code = serialization::DECL_OBJC_COMPATIBLE_ALIAS;
850 }
851 
852 void ASTDeclWriter::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
853   VisitNamedDecl(D);
854   Record.AddSourceLocation(D->getAtLoc());
855   Record.AddSourceLocation(D->getLParenLoc());
856   Record.AddTypeRef(D->getType());
857   Record.AddTypeSourceInfo(D->getTypeSourceInfo());
858   // FIXME: stable encoding
859   Record.push_back((unsigned)D->getPropertyAttributes());
860   Record.push_back((unsigned)D->getPropertyAttributesAsWritten());
861   // FIXME: stable encoding
862   Record.push_back((unsigned)D->getPropertyImplementation());
863   Record.AddDeclarationName(D->getGetterName());
864   Record.AddSourceLocation(D->getGetterNameLoc());
865   Record.AddDeclarationName(D->getSetterName());
866   Record.AddSourceLocation(D->getSetterNameLoc());
867   Record.AddDeclRef(D->getGetterMethodDecl());
868   Record.AddDeclRef(D->getSetterMethodDecl());
869   Record.AddDeclRef(D->getPropertyIvarDecl());
870   Code = serialization::DECL_OBJC_PROPERTY;
871 }
872 
873 void ASTDeclWriter::VisitObjCImplDecl(ObjCImplDecl *D) {
874   VisitObjCContainerDecl(D);
875   Record.AddDeclRef(D->getClassInterface());
876   // Abstract class (no need to define a stable serialization::DECL code).
877 }
878 
879 void ASTDeclWriter::VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D) {
880   VisitObjCImplDecl(D);
881   Record.AddSourceLocation(D->getCategoryNameLoc());
882   Code = serialization::DECL_OBJC_CATEGORY_IMPL;
883 }
884 
885 void ASTDeclWriter::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
886   VisitObjCImplDecl(D);
887   Record.AddDeclRef(D->getSuperClass());
888   Record.AddSourceLocation(D->getSuperClassLoc());
889   Record.AddSourceLocation(D->getIvarLBraceLoc());
890   Record.AddSourceLocation(D->getIvarRBraceLoc());
891   Record.push_back(D->hasNonZeroConstructors());
892   Record.push_back(D->hasDestructors());
893   Record.push_back(D->NumIvarInitializers);
894   if (D->NumIvarInitializers)
895     Record.AddCXXCtorInitializers(
896         llvm::makeArrayRef(D->init_begin(), D->init_end()));
897   Code = serialization::DECL_OBJC_IMPLEMENTATION;
898 }
899 
900 void ASTDeclWriter::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
901   VisitDecl(D);
902   Record.AddSourceLocation(D->getBeginLoc());
903   Record.AddDeclRef(D->getPropertyDecl());
904   Record.AddDeclRef(D->getPropertyIvarDecl());
905   Record.AddSourceLocation(D->getPropertyIvarDeclLoc());
906   Record.AddDeclRef(D->getGetterMethodDecl());
907   Record.AddDeclRef(D->getSetterMethodDecl());
908   Record.AddStmt(D->getGetterCXXConstructor());
909   Record.AddStmt(D->getSetterCXXAssignment());
910   Code = serialization::DECL_OBJC_PROPERTY_IMPL;
911 }
912 
913 void ASTDeclWriter::VisitFieldDecl(FieldDecl *D) {
914   VisitDeclaratorDecl(D);
915   Record.push_back(D->isMutable());
916 
917   FieldDecl::InitStorageKind ISK = D->InitStorage.getInt();
918   Record.push_back(ISK);
919   if (ISK == FieldDecl::ISK_CapturedVLAType)
920     Record.AddTypeRef(QualType(D->getCapturedVLAType(), 0));
921   else if (ISK)
922     Record.AddStmt(D->getInClassInitializer());
923 
924   Record.AddStmt(D->getBitWidth());
925 
926   if (!D->getDeclName())
927     Record.AddDeclRef(Context.getInstantiatedFromUnnamedFieldDecl(D));
928 
929   if (D->getDeclContext() == D->getLexicalDeclContext() &&
930       !D->hasAttrs() &&
931       !D->isImplicit() &&
932       !D->isUsed(false) &&
933       !D->isInvalidDecl() &&
934       !D->isReferenced() &&
935       !D->isTopLevelDeclInObjCContainer() &&
936       !D->isModulePrivate() &&
937       !D->getBitWidth() &&
938       !D->hasInClassInitializer() &&
939       !D->hasCapturedVLAType() &&
940       !D->hasExtInfo() &&
941       !ObjCIvarDecl::classofKind(D->getKind()) &&
942       !ObjCAtDefsFieldDecl::classofKind(D->getKind()) &&
943       D->getDeclName())
944     AbbrevToUse = Writer.getDeclFieldAbbrev();
945 
946   Code = serialization::DECL_FIELD;
947 }
948 
949 void ASTDeclWriter::VisitMSPropertyDecl(MSPropertyDecl *D) {
950   VisitDeclaratorDecl(D);
951   Record.AddIdentifierRef(D->getGetterId());
952   Record.AddIdentifierRef(D->getSetterId());
953   Code = serialization::DECL_MS_PROPERTY;
954 }
955 
956 void ASTDeclWriter::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
957   VisitValueDecl(D);
958   Record.push_back(D->getChainingSize());
959 
960   for (const auto *P : D->chain())
961     Record.AddDeclRef(P);
962   Code = serialization::DECL_INDIRECTFIELD;
963 }
964 
965 void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
966   VisitRedeclarable(D);
967   VisitDeclaratorDecl(D);
968   Record.push_back(D->getStorageClass());
969   Record.push_back(D->getTSCSpec());
970   Record.push_back(D->getInitStyle());
971   Record.push_back(D->isARCPseudoStrong());
972   if (!isa<ParmVarDecl>(D)) {
973     Record.push_back(D->isThisDeclarationADemotedDefinition());
974     Record.push_back(D->isExceptionVariable());
975     Record.push_back(D->isNRVOVariable());
976     Record.push_back(D->isCXXForRangeDecl());
977     Record.push_back(D->isObjCForDecl());
978     Record.push_back(D->isInline());
979     Record.push_back(D->isInlineSpecified());
980     Record.push_back(D->isConstexpr());
981     Record.push_back(D->isInitCapture());
982     Record.push_back(D->isPreviousDeclInSameBlockScope());
983     if (const auto *IPD = dyn_cast<ImplicitParamDecl>(D))
984       Record.push_back(static_cast<unsigned>(IPD->getParameterKind()));
985     else
986       Record.push_back(0);
987     Record.push_back(D->isEscapingByref());
988   }
989   Record.push_back(D->getLinkageInternal());
990 
991   if (D->getInit()) {
992     if (!D->isInitKnownICE())
993       Record.push_back(1);
994     else {
995       Record.push_back(
996           2 |
997           (D->isInitICE() ? 1 : 0) |
998           (D->ensureEvaluatedStmt()->HasConstantDestruction ? 4 : 0));
999     }
1000     Record.AddStmt(D->getInit());
1001   } else {
1002     Record.push_back(0);
1003   }
1004 
1005   if (D->hasAttr<BlocksAttr>() && D->getType()->getAsCXXRecordDecl()) {
1006     BlockVarCopyInit Init = Writer.Context->getBlockVarCopyInit(D);
1007     Record.AddStmt(Init.getCopyExpr());
1008     if (Init.getCopyExpr())
1009       Record.push_back(Init.canThrow());
1010   }
1011 
1012   if (D->getStorageDuration() == SD_Static) {
1013     bool ModulesCodegen = false;
1014     if (Writer.WritingModule &&
1015         !D->getDescribedVarTemplate() && !D->getMemberSpecializationInfo() &&
1016         !isa<VarTemplateSpecializationDecl>(D)) {
1017       // When building a C++ Modules TS module interface unit, a strong
1018       // definition in the module interface is provided by the compilation of
1019       // that module interface unit, not by its users. (Inline variables are
1020       // still emitted in module users.)
1021       ModulesCodegen =
1022           (Writer.WritingModule->Kind == Module::ModuleInterfaceUnit &&
1023            Writer.Context->GetGVALinkageForVariable(D) == GVA_StrongExternal);
1024     }
1025     Record.push_back(ModulesCodegen);
1026     if (ModulesCodegen)
1027       Writer.ModularCodegenDecls.push_back(Writer.GetDeclRef(D));
1028   }
1029 
1030   enum {
1031     VarNotTemplate = 0, VarTemplate, StaticDataMemberSpecialization
1032   };
1033   if (VarTemplateDecl *TemplD = D->getDescribedVarTemplate()) {
1034     Record.push_back(VarTemplate);
1035     Record.AddDeclRef(TemplD);
1036   } else if (MemberSpecializationInfo *SpecInfo
1037                = D->getMemberSpecializationInfo()) {
1038     Record.push_back(StaticDataMemberSpecialization);
1039     Record.AddDeclRef(SpecInfo->getInstantiatedFrom());
1040     Record.push_back(SpecInfo->getTemplateSpecializationKind());
1041     Record.AddSourceLocation(SpecInfo->getPointOfInstantiation());
1042   } else {
1043     Record.push_back(VarNotTemplate);
1044   }
1045 
1046   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1047       !D->hasAttrs() &&
1048       !D->isImplicit() &&
1049       !D->isUsed(false) &&
1050       !D->isInvalidDecl() &&
1051       !D->isReferenced() &&
1052       !D->isTopLevelDeclInObjCContainer() &&
1053       D->getAccess() == AS_none &&
1054       !D->isModulePrivate() &&
1055       !needsAnonymousDeclarationNumber(D) &&
1056       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1057       !D->hasExtInfo() &&
1058       D->getFirstDecl() == D->getMostRecentDecl() &&
1059       D->getKind() == Decl::Var &&
1060       !D->isInline() &&
1061       !D->isConstexpr() &&
1062       !D->isInitCapture() &&
1063       !D->isPreviousDeclInSameBlockScope() &&
1064       !(D->hasAttr<BlocksAttr>() && D->getType()->getAsCXXRecordDecl()) &&
1065       !D->isEscapingByref() &&
1066       D->getStorageDuration() != SD_Static &&
1067       !D->getMemberSpecializationInfo())
1068     AbbrevToUse = Writer.getDeclVarAbbrev();
1069 
1070   Code = serialization::DECL_VAR;
1071 }
1072 
1073 void ASTDeclWriter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
1074   VisitVarDecl(D);
1075   Code = serialization::DECL_IMPLICIT_PARAM;
1076 }
1077 
1078 void ASTDeclWriter::VisitParmVarDecl(ParmVarDecl *D) {
1079   VisitVarDecl(D);
1080   Record.push_back(D->isObjCMethodParameter());
1081   Record.push_back(D->getFunctionScopeDepth());
1082   Record.push_back(D->getFunctionScopeIndex());
1083   Record.push_back(D->getObjCDeclQualifier()); // FIXME: stable encoding
1084   Record.push_back(D->isKNRPromoted());
1085   Record.push_back(D->hasInheritedDefaultArg());
1086   Record.push_back(D->hasUninstantiatedDefaultArg());
1087   if (D->hasUninstantiatedDefaultArg())
1088     Record.AddStmt(D->getUninstantiatedDefaultArg());
1089   Code = serialization::DECL_PARM_VAR;
1090 
1091   assert(!D->isARCPseudoStrong()); // can be true of ImplicitParamDecl
1092 
1093   // If the assumptions about the DECL_PARM_VAR abbrev are true, use it.  Here
1094   // we dynamically check for the properties that we optimize for, but don't
1095   // know are true of all PARM_VAR_DECLs.
1096   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1097       !D->hasAttrs() &&
1098       !D->hasExtInfo() &&
1099       !D->isImplicit() &&
1100       !D->isUsed(false) &&
1101       !D->isInvalidDecl() &&
1102       !D->isReferenced() &&
1103       D->getAccess() == AS_none &&
1104       !D->isModulePrivate() &&
1105       D->getStorageClass() == 0 &&
1106       D->getInitStyle() == VarDecl::CInit && // Can params have anything else?
1107       D->getFunctionScopeDepth() == 0 &&
1108       D->getObjCDeclQualifier() == 0 &&
1109       !D->isKNRPromoted() &&
1110       !D->hasInheritedDefaultArg() &&
1111       D->getInit() == nullptr &&
1112       !D->hasUninstantiatedDefaultArg())  // No default expr.
1113     AbbrevToUse = Writer.getDeclParmVarAbbrev();
1114 
1115   // Check things we know are true of *every* PARM_VAR_DECL, which is more than
1116   // just us assuming it.
1117   assert(!D->getTSCSpec() && "PARM_VAR_DECL can't use TLS");
1118   assert(!D->isThisDeclarationADemotedDefinition()
1119          && "PARM_VAR_DECL can't be demoted definition.");
1120   assert(D->getAccess() == AS_none && "PARM_VAR_DECL can't be public/private");
1121   assert(!D->isExceptionVariable() && "PARM_VAR_DECL can't be exception var");
1122   assert(D->getPreviousDecl() == nullptr && "PARM_VAR_DECL can't be redecl");
1123   assert(!D->isStaticDataMember() &&
1124          "PARM_VAR_DECL can't be static data member");
1125 }
1126 
1127 void ASTDeclWriter::VisitDecompositionDecl(DecompositionDecl *D) {
1128   // Record the number of bindings first to simplify deserialization.
1129   Record.push_back(D->bindings().size());
1130 
1131   VisitVarDecl(D);
1132   for (auto *B : D->bindings())
1133     Record.AddDeclRef(B);
1134   Code = serialization::DECL_DECOMPOSITION;
1135 }
1136 
1137 void ASTDeclWriter::VisitBindingDecl(BindingDecl *D) {
1138   VisitValueDecl(D);
1139   Record.AddStmt(D->getBinding());
1140   Code = serialization::DECL_BINDING;
1141 }
1142 
1143 void ASTDeclWriter::VisitFileScopeAsmDecl(FileScopeAsmDecl *D) {
1144   VisitDecl(D);
1145   Record.AddStmt(D->getAsmString());
1146   Record.AddSourceLocation(D->getRParenLoc());
1147   Code = serialization::DECL_FILE_SCOPE_ASM;
1148 }
1149 
1150 void ASTDeclWriter::VisitEmptyDecl(EmptyDecl *D) {
1151   VisitDecl(D);
1152   Code = serialization::DECL_EMPTY;
1153 }
1154 
1155 void ASTDeclWriter::VisitLifetimeExtendedTemporaryDecl(
1156     LifetimeExtendedTemporaryDecl *D) {
1157   VisitDecl(D);
1158   Record.AddDeclRef(D->getExtendingDecl());
1159   Record.AddStmt(D->getTemporaryExpr());
1160   Record.push_back(static_cast<bool>(D->getValue()));
1161   if (D->getValue())
1162     Record.AddAPValue(*D->getValue());
1163   Record.push_back(D->getManglingNumber());
1164   Code = serialization::DECL_LIFETIME_EXTENDED_TEMPORARY;
1165 }
1166 void ASTDeclWriter::VisitBlockDecl(BlockDecl *D) {
1167   VisitDecl(D);
1168   Record.AddStmt(D->getBody());
1169   Record.AddTypeSourceInfo(D->getSignatureAsWritten());
1170   Record.push_back(D->param_size());
1171   for (ParmVarDecl *P : D->parameters())
1172     Record.AddDeclRef(P);
1173   Record.push_back(D->isVariadic());
1174   Record.push_back(D->blockMissingReturnType());
1175   Record.push_back(D->isConversionFromLambda());
1176   Record.push_back(D->doesNotEscape());
1177   Record.push_back(D->canAvoidCopyToHeap());
1178   Record.push_back(D->capturesCXXThis());
1179   Record.push_back(D->getNumCaptures());
1180   for (const auto &capture : D->captures()) {
1181     Record.AddDeclRef(capture.getVariable());
1182 
1183     unsigned flags = 0;
1184     if (capture.isByRef()) flags |= 1;
1185     if (capture.isNested()) flags |= 2;
1186     if (capture.hasCopyExpr()) flags |= 4;
1187     Record.push_back(flags);
1188 
1189     if (capture.hasCopyExpr()) Record.AddStmt(capture.getCopyExpr());
1190   }
1191 
1192   Code = serialization::DECL_BLOCK;
1193 }
1194 
1195 void ASTDeclWriter::VisitCapturedDecl(CapturedDecl *CD) {
1196   Record.push_back(CD->getNumParams());
1197   VisitDecl(CD);
1198   Record.push_back(CD->getContextParamPosition());
1199   Record.push_back(CD->isNothrow() ? 1 : 0);
1200   // Body is stored by VisitCapturedStmt.
1201   for (unsigned I = 0; I < CD->getNumParams(); ++I)
1202     Record.AddDeclRef(CD->getParam(I));
1203   Code = serialization::DECL_CAPTURED;
1204 }
1205 
1206 void ASTDeclWriter::VisitLinkageSpecDecl(LinkageSpecDecl *D) {
1207   VisitDecl(D);
1208   Record.push_back(D->getLanguage());
1209   Record.AddSourceLocation(D->getExternLoc());
1210   Record.AddSourceLocation(D->getRBraceLoc());
1211   Code = serialization::DECL_LINKAGE_SPEC;
1212 }
1213 
1214 void ASTDeclWriter::VisitExportDecl(ExportDecl *D) {
1215   VisitDecl(D);
1216   Record.AddSourceLocation(D->getRBraceLoc());
1217   Code = serialization::DECL_EXPORT;
1218 }
1219 
1220 void ASTDeclWriter::VisitLabelDecl(LabelDecl *D) {
1221   VisitNamedDecl(D);
1222   Record.AddSourceLocation(D->getBeginLoc());
1223   Code = serialization::DECL_LABEL;
1224 }
1225 
1226 
1227 void ASTDeclWriter::VisitNamespaceDecl(NamespaceDecl *D) {
1228   VisitRedeclarable(D);
1229   VisitNamedDecl(D);
1230   Record.push_back(D->isInline());
1231   Record.AddSourceLocation(D->getBeginLoc());
1232   Record.AddSourceLocation(D->getRBraceLoc());
1233 
1234   if (D->isOriginalNamespace())
1235     Record.AddDeclRef(D->getAnonymousNamespace());
1236   Code = serialization::DECL_NAMESPACE;
1237 
1238   if (Writer.hasChain() && D->isAnonymousNamespace() &&
1239       D == D->getMostRecentDecl()) {
1240     // This is a most recent reopening of the anonymous namespace. If its parent
1241     // is in a previous PCH (or is the TU), mark that parent for update, because
1242     // the original namespace always points to the latest re-opening of its
1243     // anonymous namespace.
1244     Decl *Parent = cast<Decl>(
1245         D->getParent()->getRedeclContext()->getPrimaryContext());
1246     if (Parent->isFromASTFile() || isa<TranslationUnitDecl>(Parent)) {
1247       Writer.DeclUpdates[Parent].push_back(
1248           ASTWriter::DeclUpdate(UPD_CXX_ADDED_ANONYMOUS_NAMESPACE, D));
1249     }
1250   }
1251 }
1252 
1253 void ASTDeclWriter::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
1254   VisitRedeclarable(D);
1255   VisitNamedDecl(D);
1256   Record.AddSourceLocation(D->getNamespaceLoc());
1257   Record.AddSourceLocation(D->getTargetNameLoc());
1258   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1259   Record.AddDeclRef(D->getNamespace());
1260   Code = serialization::DECL_NAMESPACE_ALIAS;
1261 }
1262 
1263 void ASTDeclWriter::VisitUsingDecl(UsingDecl *D) {
1264   VisitNamedDecl(D);
1265   Record.AddSourceLocation(D->getUsingLoc());
1266   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1267   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
1268   Record.AddDeclRef(D->FirstUsingShadow.getPointer());
1269   Record.push_back(D->hasTypename());
1270   Record.AddDeclRef(Context.getInstantiatedFromUsingDecl(D));
1271   Code = serialization::DECL_USING;
1272 }
1273 
1274 void ASTDeclWriter::VisitUsingPackDecl(UsingPackDecl *D) {
1275   Record.push_back(D->NumExpansions);
1276   VisitNamedDecl(D);
1277   Record.AddDeclRef(D->getInstantiatedFromUsingDecl());
1278   for (auto *E : D->expansions())
1279     Record.AddDeclRef(E);
1280   Code = serialization::DECL_USING_PACK;
1281 }
1282 
1283 void ASTDeclWriter::VisitUsingShadowDecl(UsingShadowDecl *D) {
1284   VisitRedeclarable(D);
1285   VisitNamedDecl(D);
1286   Record.AddDeclRef(D->getTargetDecl());
1287   Record.push_back(D->getIdentifierNamespace());
1288   Record.AddDeclRef(D->UsingOrNextShadow);
1289   Record.AddDeclRef(Context.getInstantiatedFromUsingShadowDecl(D));
1290   Code = serialization::DECL_USING_SHADOW;
1291 }
1292 
1293 void ASTDeclWriter::VisitConstructorUsingShadowDecl(
1294     ConstructorUsingShadowDecl *D) {
1295   VisitUsingShadowDecl(D);
1296   Record.AddDeclRef(D->NominatedBaseClassShadowDecl);
1297   Record.AddDeclRef(D->ConstructedBaseClassShadowDecl);
1298   Record.push_back(D->IsVirtual);
1299   Code = serialization::DECL_CONSTRUCTOR_USING_SHADOW;
1300 }
1301 
1302 void ASTDeclWriter::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1303   VisitNamedDecl(D);
1304   Record.AddSourceLocation(D->getUsingLoc());
1305   Record.AddSourceLocation(D->getNamespaceKeyLocation());
1306   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1307   Record.AddDeclRef(D->getNominatedNamespace());
1308   Record.AddDeclRef(dyn_cast<Decl>(D->getCommonAncestor()));
1309   Code = serialization::DECL_USING_DIRECTIVE;
1310 }
1311 
1312 void ASTDeclWriter::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1313   VisitValueDecl(D);
1314   Record.AddSourceLocation(D->getUsingLoc());
1315   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1316   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
1317   Record.AddSourceLocation(D->getEllipsisLoc());
1318   Code = serialization::DECL_UNRESOLVED_USING_VALUE;
1319 }
1320 
1321 void ASTDeclWriter::VisitUnresolvedUsingTypenameDecl(
1322                                                UnresolvedUsingTypenameDecl *D) {
1323   VisitTypeDecl(D);
1324   Record.AddSourceLocation(D->getTypenameLoc());
1325   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1326   Record.AddSourceLocation(D->getEllipsisLoc());
1327   Code = serialization::DECL_UNRESOLVED_USING_TYPENAME;
1328 }
1329 
1330 void ASTDeclWriter::VisitCXXRecordDecl(CXXRecordDecl *D) {
1331   VisitRecordDecl(D);
1332 
1333   enum {
1334     CXXRecNotTemplate = 0, CXXRecTemplate, CXXRecMemberSpecialization
1335   };
1336   if (ClassTemplateDecl *TemplD = D->getDescribedClassTemplate()) {
1337     Record.push_back(CXXRecTemplate);
1338     Record.AddDeclRef(TemplD);
1339   } else if (MemberSpecializationInfo *MSInfo
1340                = D->getMemberSpecializationInfo()) {
1341     Record.push_back(CXXRecMemberSpecialization);
1342     Record.AddDeclRef(MSInfo->getInstantiatedFrom());
1343     Record.push_back(MSInfo->getTemplateSpecializationKind());
1344     Record.AddSourceLocation(MSInfo->getPointOfInstantiation());
1345   } else {
1346     Record.push_back(CXXRecNotTemplate);
1347   }
1348 
1349   Record.push_back(D->isThisDeclarationADefinition());
1350   if (D->isThisDeclarationADefinition())
1351     Record.AddCXXDefinitionData(D);
1352 
1353   // Store (what we currently believe to be) the key function to avoid
1354   // deserializing every method so we can compute it.
1355   if (D->isCompleteDefinition())
1356     Record.AddDeclRef(Context.getCurrentKeyFunction(D));
1357 
1358   Code = serialization::DECL_CXX_RECORD;
1359 }
1360 
1361 void ASTDeclWriter::VisitCXXMethodDecl(CXXMethodDecl *D) {
1362   VisitFunctionDecl(D);
1363   if (D->isCanonicalDecl()) {
1364     Record.push_back(D->size_overridden_methods());
1365     for (const CXXMethodDecl *MD : D->overridden_methods())
1366       Record.AddDeclRef(MD);
1367   } else {
1368     // We only need to record overridden methods once for the canonical decl.
1369     Record.push_back(0);
1370   }
1371 
1372   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1373       D->getFirstDecl() == D->getMostRecentDecl() &&
1374       !D->isInvalidDecl() &&
1375       !D->hasAttrs() &&
1376       !D->isTopLevelDeclInObjCContainer() &&
1377       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1378       !D->hasExtInfo() &&
1379       !D->hasInheritedPrototype() &&
1380       D->hasWrittenPrototype())
1381     AbbrevToUse = Writer.getDeclCXXMethodAbbrev();
1382 
1383   Code = serialization::DECL_CXX_METHOD;
1384 }
1385 
1386 void ASTDeclWriter::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1387   Record.push_back(D->getTraillingAllocKind());
1388   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
1389   if (auto Inherited = D->getInheritedConstructor()) {
1390     Record.AddDeclRef(Inherited.getShadowDecl());
1391     Record.AddDeclRef(Inherited.getConstructor());
1392   }
1393 
1394   VisitCXXMethodDecl(D);
1395   Code = serialization::DECL_CXX_CONSTRUCTOR;
1396 }
1397 
1398 void ASTDeclWriter::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1399   VisitCXXMethodDecl(D);
1400 
1401   Record.AddDeclRef(D->getOperatorDelete());
1402   if (D->getOperatorDelete())
1403     Record.AddStmt(D->getOperatorDeleteThisArg());
1404 
1405   Code = serialization::DECL_CXX_DESTRUCTOR;
1406 }
1407 
1408 void ASTDeclWriter::VisitCXXConversionDecl(CXXConversionDecl *D) {
1409   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
1410   VisitCXXMethodDecl(D);
1411   Code = serialization::DECL_CXX_CONVERSION;
1412 }
1413 
1414 void ASTDeclWriter::VisitImportDecl(ImportDecl *D) {
1415   VisitDecl(D);
1416   Record.push_back(Writer.getSubmoduleID(D->getImportedModule()));
1417   ArrayRef<SourceLocation> IdentifierLocs = D->getIdentifierLocs();
1418   Record.push_back(!IdentifierLocs.empty());
1419   if (IdentifierLocs.empty()) {
1420     Record.AddSourceLocation(D->getEndLoc());
1421     Record.push_back(1);
1422   } else {
1423     for (unsigned I = 0, N = IdentifierLocs.size(); I != N; ++I)
1424       Record.AddSourceLocation(IdentifierLocs[I]);
1425     Record.push_back(IdentifierLocs.size());
1426   }
1427   // Note: the number of source locations must always be the last element in
1428   // the record.
1429   Code = serialization::DECL_IMPORT;
1430 }
1431 
1432 void ASTDeclWriter::VisitAccessSpecDecl(AccessSpecDecl *D) {
1433   VisitDecl(D);
1434   Record.AddSourceLocation(D->getColonLoc());
1435   Code = serialization::DECL_ACCESS_SPEC;
1436 }
1437 
1438 void ASTDeclWriter::VisitFriendDecl(FriendDecl *D) {
1439   // Record the number of friend type template parameter lists here
1440   // so as to simplify memory allocation during deserialization.
1441   Record.push_back(D->NumTPLists);
1442   VisitDecl(D);
1443   bool hasFriendDecl = D->Friend.is<NamedDecl*>();
1444   Record.push_back(hasFriendDecl);
1445   if (hasFriendDecl)
1446     Record.AddDeclRef(D->getFriendDecl());
1447   else
1448     Record.AddTypeSourceInfo(D->getFriendType());
1449   for (unsigned i = 0; i < D->NumTPLists; ++i)
1450     Record.AddTemplateParameterList(D->getFriendTypeTemplateParameterList(i));
1451   Record.AddDeclRef(D->getNextFriend());
1452   Record.push_back(D->UnsupportedFriend);
1453   Record.AddSourceLocation(D->FriendLoc);
1454   Code = serialization::DECL_FRIEND;
1455 }
1456 
1457 void ASTDeclWriter::VisitFriendTemplateDecl(FriendTemplateDecl *D) {
1458   VisitDecl(D);
1459   Record.push_back(D->getNumTemplateParameters());
1460   for (unsigned i = 0, e = D->getNumTemplateParameters(); i != e; ++i)
1461     Record.AddTemplateParameterList(D->getTemplateParameterList(i));
1462   Record.push_back(D->getFriendDecl() != nullptr);
1463   if (D->getFriendDecl())
1464     Record.AddDeclRef(D->getFriendDecl());
1465   else
1466     Record.AddTypeSourceInfo(D->getFriendType());
1467   Record.AddSourceLocation(D->getFriendLoc());
1468   Code = serialization::DECL_FRIEND_TEMPLATE;
1469 }
1470 
1471 void ASTDeclWriter::VisitTemplateDecl(TemplateDecl *D) {
1472   VisitNamedDecl(D);
1473 
1474   Record.AddDeclRef(D->getTemplatedDecl());
1475   Record.AddTemplateParameterList(D->getTemplateParameters());
1476 }
1477 
1478 void ASTDeclWriter::VisitConceptDecl(ConceptDecl *D) {
1479   VisitTemplateDecl(D);
1480   Record.AddStmt(D->getConstraintExpr());
1481   Code = serialization::DECL_CONCEPT;
1482 }
1483 
1484 void ASTDeclWriter::VisitRequiresExprBodyDecl(RequiresExprBodyDecl *D) {
1485   Code = serialization::DECL_REQUIRES_EXPR_BODY;
1486 }
1487 
1488 void ASTDeclWriter::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
1489   VisitRedeclarable(D);
1490 
1491   // Emit data to initialize CommonOrPrev before VisitTemplateDecl so that
1492   // getCommonPtr() can be used while this is still initializing.
1493   if (D->isFirstDecl()) {
1494     // This declaration owns the 'common' pointer, so serialize that data now.
1495     Record.AddDeclRef(D->getInstantiatedFromMemberTemplate());
1496     if (D->getInstantiatedFromMemberTemplate())
1497       Record.push_back(D->isMemberSpecialization());
1498   }
1499 
1500   VisitTemplateDecl(D);
1501   Record.push_back(D->getIdentifierNamespace());
1502 }
1503 
1504 void ASTDeclWriter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
1505   VisitRedeclarableTemplateDecl(D);
1506 
1507   if (D->isFirstDecl())
1508     AddTemplateSpecializations(D);
1509   Code = serialization::DECL_CLASS_TEMPLATE;
1510 }
1511 
1512 void ASTDeclWriter::VisitClassTemplateSpecializationDecl(
1513                                            ClassTemplateSpecializationDecl *D) {
1514   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1515 
1516   VisitCXXRecordDecl(D);
1517 
1518   llvm::PointerUnion<ClassTemplateDecl *,
1519                      ClassTemplatePartialSpecializationDecl *> InstFrom
1520     = D->getSpecializedTemplateOrPartial();
1521   if (Decl *InstFromD = InstFrom.dyn_cast<ClassTemplateDecl *>()) {
1522     Record.AddDeclRef(InstFromD);
1523   } else {
1524     Record.AddDeclRef(InstFrom.get<ClassTemplatePartialSpecializationDecl *>());
1525     Record.AddTemplateArgumentList(&D->getTemplateInstantiationArgs());
1526   }
1527 
1528   Record.AddTemplateArgumentList(&D->getTemplateArgs());
1529   Record.AddSourceLocation(D->getPointOfInstantiation());
1530   Record.push_back(D->getSpecializationKind());
1531   Record.push_back(D->isCanonicalDecl());
1532 
1533   if (D->isCanonicalDecl()) {
1534     // When reading, we'll add it to the folding set of the following template.
1535     Record.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl());
1536   }
1537 
1538   // Explicit info.
1539   Record.AddTypeSourceInfo(D->getTypeAsWritten());
1540   if (D->getTypeAsWritten()) {
1541     Record.AddSourceLocation(D->getExternLoc());
1542     Record.AddSourceLocation(D->getTemplateKeywordLoc());
1543   }
1544 
1545   Code = serialization::DECL_CLASS_TEMPLATE_SPECIALIZATION;
1546 }
1547 
1548 void ASTDeclWriter::VisitClassTemplatePartialSpecializationDecl(
1549                                     ClassTemplatePartialSpecializationDecl *D) {
1550   Record.AddTemplateParameterList(D->getTemplateParameters());
1551   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1552 
1553   VisitClassTemplateSpecializationDecl(D);
1554 
1555   // These are read/set from/to the first declaration.
1556   if (D->getPreviousDecl() == nullptr) {
1557     Record.AddDeclRef(D->getInstantiatedFromMember());
1558     Record.push_back(D->isMemberSpecialization());
1559   }
1560 
1561   Code = serialization::DECL_CLASS_TEMPLATE_PARTIAL_SPECIALIZATION;
1562 }
1563 
1564 void ASTDeclWriter::VisitVarTemplateDecl(VarTemplateDecl *D) {
1565   VisitRedeclarableTemplateDecl(D);
1566 
1567   if (D->isFirstDecl())
1568     AddTemplateSpecializations(D);
1569   Code = serialization::DECL_VAR_TEMPLATE;
1570 }
1571 
1572 void ASTDeclWriter::VisitVarTemplateSpecializationDecl(
1573     VarTemplateSpecializationDecl *D) {
1574   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1575 
1576   VisitVarDecl(D);
1577 
1578   llvm::PointerUnion<VarTemplateDecl *, VarTemplatePartialSpecializationDecl *>
1579   InstFrom = D->getSpecializedTemplateOrPartial();
1580   if (Decl *InstFromD = InstFrom.dyn_cast<VarTemplateDecl *>()) {
1581     Record.AddDeclRef(InstFromD);
1582   } else {
1583     Record.AddDeclRef(InstFrom.get<VarTemplatePartialSpecializationDecl *>());
1584     Record.AddTemplateArgumentList(&D->getTemplateInstantiationArgs());
1585   }
1586 
1587   // Explicit info.
1588   Record.AddTypeSourceInfo(D->getTypeAsWritten());
1589   if (D->getTypeAsWritten()) {
1590     Record.AddSourceLocation(D->getExternLoc());
1591     Record.AddSourceLocation(D->getTemplateKeywordLoc());
1592   }
1593 
1594   Record.AddTemplateArgumentList(&D->getTemplateArgs());
1595   Record.AddSourceLocation(D->getPointOfInstantiation());
1596   Record.push_back(D->getSpecializationKind());
1597   Record.push_back(D->IsCompleteDefinition);
1598   Record.push_back(D->isCanonicalDecl());
1599 
1600   if (D->isCanonicalDecl()) {
1601     // When reading, we'll add it to the folding set of the following template.
1602     Record.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl());
1603   }
1604 
1605   Code = serialization::DECL_VAR_TEMPLATE_SPECIALIZATION;
1606 }
1607 
1608 void ASTDeclWriter::VisitVarTemplatePartialSpecializationDecl(
1609     VarTemplatePartialSpecializationDecl *D) {
1610   Record.AddTemplateParameterList(D->getTemplateParameters());
1611   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1612 
1613   VisitVarTemplateSpecializationDecl(D);
1614 
1615   // These are read/set from/to the first declaration.
1616   if (D->getPreviousDecl() == nullptr) {
1617     Record.AddDeclRef(D->getInstantiatedFromMember());
1618     Record.push_back(D->isMemberSpecialization());
1619   }
1620 
1621   Code = serialization::DECL_VAR_TEMPLATE_PARTIAL_SPECIALIZATION;
1622 }
1623 
1624 void ASTDeclWriter::VisitClassScopeFunctionSpecializationDecl(
1625                                     ClassScopeFunctionSpecializationDecl *D) {
1626   VisitDecl(D);
1627   Record.AddDeclRef(D->getSpecialization());
1628   Record.push_back(D->hasExplicitTemplateArgs());
1629   if (D->hasExplicitTemplateArgs())
1630     Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1631   Code = serialization::DECL_CLASS_SCOPE_FUNCTION_SPECIALIZATION;
1632 }
1633 
1634 
1635 void ASTDeclWriter::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
1636   VisitRedeclarableTemplateDecl(D);
1637 
1638   if (D->isFirstDecl())
1639     AddTemplateSpecializations(D);
1640   Code = serialization::DECL_FUNCTION_TEMPLATE;
1641 }
1642 
1643 void ASTDeclWriter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
1644   Record.push_back(D->hasTypeConstraint());
1645   VisitTypeDecl(D);
1646 
1647   Record.push_back(D->wasDeclaredWithTypename());
1648 
1649   const TypeConstraint *TC = D->getTypeConstraint();
1650   Record.push_back(TC != nullptr);
1651   if (TC) {
1652     Record.AddNestedNameSpecifierLoc(TC->getNestedNameSpecifierLoc());
1653     Record.AddDeclarationNameInfo(TC->getConceptNameInfo());
1654     Record.AddDeclRef(TC->getNamedConcept());
1655     Record.push_back(TC->getTemplateArgsAsWritten() != nullptr);
1656     if (TC->getTemplateArgsAsWritten())
1657       Record.AddASTTemplateArgumentListInfo(TC->getTemplateArgsAsWritten());
1658     Record.AddStmt(TC->getImmediatelyDeclaredConstraint());
1659     Record.push_back(D->isExpandedParameterPack());
1660     if (D->isExpandedParameterPack())
1661       Record.push_back(D->getNumExpansionParameters());
1662   }
1663 
1664   bool OwnsDefaultArg = D->hasDefaultArgument() &&
1665                         !D->defaultArgumentWasInherited();
1666   Record.push_back(OwnsDefaultArg);
1667   if (OwnsDefaultArg)
1668     Record.AddTypeSourceInfo(D->getDefaultArgumentInfo());
1669 
1670   Code = serialization::DECL_TEMPLATE_TYPE_PARM;
1671 }
1672 
1673 void ASTDeclWriter::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
1674   // For an expanded parameter pack, record the number of expansion types here
1675   // so that it's easier for deserialization to allocate the right amount of
1676   // memory.
1677   Expr *TypeConstraint = D->getPlaceholderTypeConstraint();
1678   Record.push_back(!!TypeConstraint);
1679   if (D->isExpandedParameterPack())
1680     Record.push_back(D->getNumExpansionTypes());
1681 
1682   VisitDeclaratorDecl(D);
1683   // TemplateParmPosition.
1684   Record.push_back(D->getDepth());
1685   Record.push_back(D->getPosition());
1686   if (TypeConstraint)
1687     Record.AddStmt(TypeConstraint);
1688 
1689   if (D->isExpandedParameterPack()) {
1690     for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1691       Record.AddTypeRef(D->getExpansionType(I));
1692       Record.AddTypeSourceInfo(D->getExpansionTypeSourceInfo(I));
1693     }
1694 
1695     Code = serialization::DECL_EXPANDED_NON_TYPE_TEMPLATE_PARM_PACK;
1696   } else {
1697     // Rest of NonTypeTemplateParmDecl.
1698     Record.push_back(D->isParameterPack());
1699     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1700                           !D->defaultArgumentWasInherited();
1701     Record.push_back(OwnsDefaultArg);
1702     if (OwnsDefaultArg)
1703       Record.AddStmt(D->getDefaultArgument());
1704     Code = serialization::DECL_NON_TYPE_TEMPLATE_PARM;
1705   }
1706 }
1707 
1708 void ASTDeclWriter::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
1709   // For an expanded parameter pack, record the number of expansion types here
1710   // so that it's easier for deserialization to allocate the right amount of
1711   // memory.
1712   if (D->isExpandedParameterPack())
1713     Record.push_back(D->getNumExpansionTemplateParameters());
1714 
1715   VisitTemplateDecl(D);
1716   // TemplateParmPosition.
1717   Record.push_back(D->getDepth());
1718   Record.push_back(D->getPosition());
1719 
1720   if (D->isExpandedParameterPack()) {
1721     for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
1722          I != N; ++I)
1723       Record.AddTemplateParameterList(D->getExpansionTemplateParameters(I));
1724     Code = serialization::DECL_EXPANDED_TEMPLATE_TEMPLATE_PARM_PACK;
1725   } else {
1726     // Rest of TemplateTemplateParmDecl.
1727     Record.push_back(D->isParameterPack());
1728     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1729                           !D->defaultArgumentWasInherited();
1730     Record.push_back(OwnsDefaultArg);
1731     if (OwnsDefaultArg)
1732       Record.AddTemplateArgumentLoc(D->getDefaultArgument());
1733     Code = serialization::DECL_TEMPLATE_TEMPLATE_PARM;
1734   }
1735 }
1736 
1737 void ASTDeclWriter::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
1738   VisitRedeclarableTemplateDecl(D);
1739   Code = serialization::DECL_TYPE_ALIAS_TEMPLATE;
1740 }
1741 
1742 void ASTDeclWriter::VisitStaticAssertDecl(StaticAssertDecl *D) {
1743   VisitDecl(D);
1744   Record.AddStmt(D->getAssertExpr());
1745   Record.push_back(D->isFailed());
1746   Record.AddStmt(D->getMessage());
1747   Record.AddSourceLocation(D->getRParenLoc());
1748   Code = serialization::DECL_STATIC_ASSERT;
1749 }
1750 
1751 /// Emit the DeclContext part of a declaration context decl.
1752 void ASTDeclWriter::VisitDeclContext(DeclContext *DC) {
1753   Record.AddOffset(Writer.WriteDeclContextLexicalBlock(Context, DC));
1754   Record.AddOffset(Writer.WriteDeclContextVisibleBlock(Context, DC));
1755 }
1756 
1757 const Decl *ASTWriter::getFirstLocalDecl(const Decl *D) {
1758   assert(IsLocalDecl(D) && "expected a local declaration");
1759 
1760   const Decl *Canon = D->getCanonicalDecl();
1761   if (IsLocalDecl(Canon))
1762     return Canon;
1763 
1764   const Decl *&CacheEntry = FirstLocalDeclCache[Canon];
1765   if (CacheEntry)
1766     return CacheEntry;
1767 
1768   for (const Decl *Redecl = D; Redecl; Redecl = Redecl->getPreviousDecl())
1769     if (IsLocalDecl(Redecl))
1770       D = Redecl;
1771   return CacheEntry = D;
1772 }
1773 
1774 template <typename T>
1775 void ASTDeclWriter::VisitRedeclarable(Redeclarable<T> *D) {
1776   T *First = D->getFirstDecl();
1777   T *MostRecent = First->getMostRecentDecl();
1778   T *DAsT = static_cast<T *>(D);
1779   if (MostRecent != First) {
1780     assert(isRedeclarableDeclKind(DAsT->getKind()) &&
1781            "Not considered redeclarable?");
1782 
1783     Record.AddDeclRef(First);
1784 
1785     // Write out a list of local redeclarations of this declaration if it's the
1786     // first local declaration in the chain.
1787     const Decl *FirstLocal = Writer.getFirstLocalDecl(DAsT);
1788     if (DAsT == FirstLocal) {
1789       // Emit a list of all imported first declarations so that we can be sure
1790       // that all redeclarations visible to this module are before D in the
1791       // redecl chain.
1792       unsigned I = Record.size();
1793       Record.push_back(0);
1794       if (Writer.Chain)
1795         AddFirstDeclFromEachModule(DAsT, /*IncludeLocal*/false);
1796       // This is the number of imported first declarations + 1.
1797       Record[I] = Record.size() - I;
1798 
1799       // Collect the set of local redeclarations of this declaration, from
1800       // newest to oldest.
1801       ASTWriter::RecordData LocalRedecls;
1802       ASTRecordWriter LocalRedeclWriter(Record, LocalRedecls);
1803       for (const Decl *Prev = FirstLocal->getMostRecentDecl();
1804            Prev != FirstLocal; Prev = Prev->getPreviousDecl())
1805         if (!Prev->isFromASTFile())
1806           LocalRedeclWriter.AddDeclRef(Prev);
1807 
1808       // If we have any redecls, write them now as a separate record preceding
1809       // the declaration itself.
1810       if (LocalRedecls.empty())
1811         Record.push_back(0);
1812       else
1813         Record.AddOffset(LocalRedeclWriter.Emit(LOCAL_REDECLARATIONS));
1814     } else {
1815       Record.push_back(0);
1816       Record.AddDeclRef(FirstLocal);
1817     }
1818 
1819     // Make sure that we serialize both the previous and the most-recent
1820     // declarations, which (transitively) ensures that all declarations in the
1821     // chain get serialized.
1822     //
1823     // FIXME: This is not correct; when we reach an imported declaration we
1824     // won't emit its previous declaration.
1825     (void)Writer.GetDeclRef(D->getPreviousDecl());
1826     (void)Writer.GetDeclRef(MostRecent);
1827   } else {
1828     // We use the sentinel value 0 to indicate an only declaration.
1829     Record.push_back(0);
1830   }
1831 }
1832 
1833 void ASTDeclWriter::VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D) {
1834   Record.push_back(D->varlist_size());
1835   VisitDecl(D);
1836   for (auto *I : D->varlists())
1837     Record.AddStmt(I);
1838   Code = serialization::DECL_OMP_THREADPRIVATE;
1839 }
1840 
1841 void ASTDeclWriter::VisitOMPAllocateDecl(OMPAllocateDecl *D) {
1842   Record.push_back(D->varlist_size());
1843   Record.push_back(D->clauselist_size());
1844   VisitDecl(D);
1845   for (auto *I : D->varlists())
1846     Record.AddStmt(I);
1847   for (OMPClause *C : D->clauselists())
1848     Record.writeOMPClause(C);
1849   Code = serialization::DECL_OMP_ALLOCATE;
1850 }
1851 
1852 void ASTDeclWriter::VisitOMPRequiresDecl(OMPRequiresDecl *D) {
1853   Record.push_back(D->clauselist_size());
1854   VisitDecl(D);
1855   for (OMPClause *C : D->clauselists())
1856     Record.writeOMPClause(C);
1857   Code = serialization::DECL_OMP_REQUIRES;
1858 }
1859 
1860 void ASTDeclWriter::VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D) {
1861   VisitValueDecl(D);
1862   Record.AddSourceLocation(D->getBeginLoc());
1863   Record.AddStmt(D->getCombinerIn());
1864   Record.AddStmt(D->getCombinerOut());
1865   Record.AddStmt(D->getCombiner());
1866   Record.AddStmt(D->getInitOrig());
1867   Record.AddStmt(D->getInitPriv());
1868   Record.AddStmt(D->getInitializer());
1869   Record.push_back(D->getInitializerKind());
1870   Record.AddDeclRef(D->getPrevDeclInScope());
1871   Code = serialization::DECL_OMP_DECLARE_REDUCTION;
1872 }
1873 
1874 void ASTDeclWriter::VisitOMPDeclareMapperDecl(OMPDeclareMapperDecl *D) {
1875   Record.push_back(D->clauselist_size());
1876   VisitValueDecl(D);
1877   Record.AddSourceLocation(D->getBeginLoc());
1878   Record.AddStmt(D->getMapperVarRef());
1879   Record.AddDeclarationName(D->getVarName());
1880   Record.AddDeclRef(D->getPrevDeclInScope());
1881   for (OMPClause *C : D->clauselists())
1882     Record.writeOMPClause(C);
1883   Code = serialization::DECL_OMP_DECLARE_MAPPER;
1884 }
1885 
1886 void ASTDeclWriter::VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D) {
1887   VisitVarDecl(D);
1888   Code = serialization::DECL_OMP_CAPTUREDEXPR;
1889 }
1890 
1891 //===----------------------------------------------------------------------===//
1892 // ASTWriter Implementation
1893 //===----------------------------------------------------------------------===//
1894 
1895 void ASTWriter::WriteDeclAbbrevs() {
1896   using namespace llvm;
1897 
1898   std::shared_ptr<BitCodeAbbrev> Abv;
1899 
1900   // Abbreviation for DECL_FIELD
1901   Abv = std::make_shared<BitCodeAbbrev>();
1902   Abv->Add(BitCodeAbbrevOp(serialization::DECL_FIELD));
1903   // Decl
1904   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1905   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1906   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1907   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1908   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1909   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1910   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1911   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1912   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1913   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1914   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1915   // NamedDecl
1916   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1917   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1918   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1919   // ValueDecl
1920   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1921   // DeclaratorDecl
1922   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1923   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1924   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
1925   // FieldDecl
1926   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1927   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
1928   // Type Source Info
1929   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1930   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1931   DeclFieldAbbrev = Stream.EmitAbbrev(std::move(Abv));
1932 
1933   // Abbreviation for DECL_OBJC_IVAR
1934   Abv = std::make_shared<BitCodeAbbrev>();
1935   Abv->Add(BitCodeAbbrevOp(serialization::DECL_OBJC_IVAR));
1936   // Decl
1937   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1938   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1939   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1940   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1941   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1942   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1943   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1944   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1945   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1946   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1947   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1948   // NamedDecl
1949   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1950   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1951   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1952   // ValueDecl
1953   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1954   // DeclaratorDecl
1955   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1956   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1957   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
1958   // FieldDecl
1959   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1960   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
1961   // ObjC Ivar
1962   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getAccessControl
1963   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getSynthesize
1964   // Type Source Info
1965   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1966   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1967   DeclObjCIvarAbbrev = Stream.EmitAbbrev(std::move(Abv));
1968 
1969   // Abbreviation for DECL_ENUM
1970   Abv = std::make_shared<BitCodeAbbrev>();
1971   Abv->Add(BitCodeAbbrevOp(serialization::DECL_ENUM));
1972   // Redeclarable
1973   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1974   // Decl
1975   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1976   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1977   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1978   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1979   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1980   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1981   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1982   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1983   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1984   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1985   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1986   // NamedDecl
1987   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1988   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1989   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1990   // TypeDecl
1991   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1992   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1993   // TagDecl
1994   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
1995   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
1996   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
1997   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
1998   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
1999   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
2000   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2001   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2002   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
2003   // EnumDecl
2004   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddTypeRef
2005   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IntegerType
2006   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getPromotionType
2007   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumPositiveBits
2008   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumNegativeBits
2009   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScoped
2010   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScopedUsingClassTag
2011   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isFixed
2012   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));// ODRHash
2013   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InstantiatedMembEnum
2014   // DC
2015   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
2016   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
2017   DeclEnumAbbrev = Stream.EmitAbbrev(std::move(Abv));
2018 
2019   // Abbreviation for DECL_RECORD
2020   Abv = std::make_shared<BitCodeAbbrev>();
2021   Abv->Add(BitCodeAbbrevOp(serialization::DECL_RECORD));
2022   // Redeclarable
2023   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2024   // Decl
2025   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2026   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2027   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2028   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2029   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2030   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2031   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2032   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2033   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2034   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2035   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2036   // NamedDecl
2037   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2038   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2039   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2040   // TypeDecl
2041   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
2042   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
2043   // TagDecl
2044   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
2045   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
2046   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
2047   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
2048   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
2049   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
2050   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2051   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2052   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
2053   // RecordDecl
2054   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // FlexibleArrayMember
2055   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // AnonymousStructUnion
2056   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasObjectMember
2057   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasVolatileMember
2058 
2059   // isNonTrivialToPrimitiveDefaultInitialize
2060   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2061   // isNonTrivialToPrimitiveCopy
2062   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2063   // isNonTrivialToPrimitiveDestroy
2064   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2065   // hasNonTrivialToPrimitiveDefaultInitializeCUnion
2066   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2067   // hasNonTrivialToPrimitiveDestructCUnion
2068   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2069   // hasNonTrivialToPrimitiveCopyCUnion
2070   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2071   // isParamDestroyedInCallee
2072   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2073   // getArgPassingRestrictions
2074   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));
2075 
2076   // DC
2077   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
2078   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
2079   DeclRecordAbbrev = Stream.EmitAbbrev(std::move(Abv));
2080 
2081   // Abbreviation for DECL_PARM_VAR
2082   Abv = std::make_shared<BitCodeAbbrev>();
2083   Abv->Add(BitCodeAbbrevOp(serialization::DECL_PARM_VAR));
2084   // Redeclarable
2085   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2086   // Decl
2087   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2088   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2089   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2090   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2091   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2092   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2093   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2094   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2095   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2096   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2097   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2098   // NamedDecl
2099   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2100   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2101   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2102   // ValueDecl
2103   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2104   // DeclaratorDecl
2105   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
2106   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
2107   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
2108   // VarDecl
2109   Abv->Add(BitCodeAbbrevOp(0));                       // SClass
2110   Abv->Add(BitCodeAbbrevOp(0));                       // TSCSpec
2111   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
2112   Abv->Add(BitCodeAbbrevOp(0));                       // ARCPseudoStrong
2113   Abv->Add(BitCodeAbbrevOp(0));                       // Linkage
2114   Abv->Add(BitCodeAbbrevOp(0));                       // HasInit
2115   Abv->Add(BitCodeAbbrevOp(0));                   // HasMemberSpecializationInfo
2116   // ParmVarDecl
2117   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsObjCMethodParameter
2118   Abv->Add(BitCodeAbbrevOp(0));                       // ScopeDepth
2119   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ScopeIndex
2120   Abv->Add(BitCodeAbbrevOp(0));                       // ObjCDeclQualifier
2121   Abv->Add(BitCodeAbbrevOp(0));                       // KNRPromoted
2122   Abv->Add(BitCodeAbbrevOp(0));                       // HasInheritedDefaultArg
2123   Abv->Add(BitCodeAbbrevOp(0));                   // HasUninstantiatedDefaultArg
2124   // Type Source Info
2125   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2126   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2127   DeclParmVarAbbrev = Stream.EmitAbbrev(std::move(Abv));
2128 
2129   // Abbreviation for DECL_TYPEDEF
2130   Abv = std::make_shared<BitCodeAbbrev>();
2131   Abv->Add(BitCodeAbbrevOp(serialization::DECL_TYPEDEF));
2132   // Redeclarable
2133   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2134   // Decl
2135   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2136   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2137   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2138   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2139   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2140   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isUsed
2141   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isReferenced
2142   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2143   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // C++ AccessSpecifier
2144   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2145   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2146   // NamedDecl
2147   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2148   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2149   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2150   // TypeDecl
2151   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
2152   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
2153   // TypedefDecl
2154   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2155   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2156   DeclTypedefAbbrev = Stream.EmitAbbrev(std::move(Abv));
2157 
2158   // Abbreviation for DECL_VAR
2159   Abv = std::make_shared<BitCodeAbbrev>();
2160   Abv->Add(BitCodeAbbrevOp(serialization::DECL_VAR));
2161   // Redeclarable
2162   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2163   // Decl
2164   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2165   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2166   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2167   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2168   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2169   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2170   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2171   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2172   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2173   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2174   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2175   // NamedDecl
2176   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2177   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2178   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2179   // ValueDecl
2180   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2181   // DeclaratorDecl
2182   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
2183   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
2184   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
2185   // VarDecl
2186   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // SClass
2187   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // TSCSpec
2188   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // InitStyle
2189   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isARCPseudoStrong
2190   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsThisDeclarationADemotedDefinition
2191   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isExceptionVariable
2192   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isNRVOVariable
2193   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCXXForRangeDecl
2194   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isObjCForDecl
2195   Abv->Add(BitCodeAbbrevOp(0));                         // isInline
2196   Abv->Add(BitCodeAbbrevOp(0));                         // isInlineSpecified
2197   Abv->Add(BitCodeAbbrevOp(0));                         // isConstexpr
2198   Abv->Add(BitCodeAbbrevOp(0));                         // isInitCapture
2199   Abv->Add(BitCodeAbbrevOp(0));                         // isPrevDeclInSameScope
2200   Abv->Add(BitCodeAbbrevOp(0));                         // ImplicitParamKind
2201   Abv->Add(BitCodeAbbrevOp(0));                         // EscapingByref
2202   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
2203   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // IsInitICE (local)
2204   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // VarKind (local enum)
2205   // Type Source Info
2206   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2207   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2208   DeclVarAbbrev = Stream.EmitAbbrev(std::move(Abv));
2209 
2210   // Abbreviation for DECL_CXX_METHOD
2211   Abv = std::make_shared<BitCodeAbbrev>();
2212   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CXX_METHOD));
2213   // RedeclarableDecl
2214   Abv->Add(BitCodeAbbrevOp(0));                         // CanonicalDecl
2215   // Decl
2216   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // DeclContext
2217   Abv->Add(BitCodeAbbrevOp(0));                         // LexicalDeclContext
2218   Abv->Add(BitCodeAbbrevOp(0));                         // Invalid
2219   Abv->Add(BitCodeAbbrevOp(0));                         // HasAttrs
2220   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Implicit
2221   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Used
2222   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Referenced
2223   Abv->Add(BitCodeAbbrevOp(0));                         // InObjCContainer
2224   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // Access
2225   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ModulePrivate
2226   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SubmoduleID
2227   // NamedDecl
2228   Abv->Add(BitCodeAbbrevOp(DeclarationName::Identifier)); // NameKind
2229   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Identifier
2230   Abv->Add(BitCodeAbbrevOp(0));                         // AnonDeclNumber
2231   // ValueDecl
2232   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Type
2233   // DeclaratorDecl
2234   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InnerLocStart
2235   Abv->Add(BitCodeAbbrevOp(0));                         // HasExtInfo
2236   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // TSIType
2237   // FunctionDecl
2238   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 11)); // IDNS
2239   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // StorageClass
2240   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Inline
2241   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // InlineSpecified
2242   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // VirtualAsWritten
2243   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Pure
2244   Abv->Add(BitCodeAbbrevOp(0));                         // HasInheritedProto
2245   Abv->Add(BitCodeAbbrevOp(1));                         // HasWrittenProto
2246   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Deleted
2247   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Trivial
2248   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // TrivialForCall
2249   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Defaulted
2250   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ExplicitlyDefaulted
2251   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ImplicitReturnZero
2252   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Constexpr
2253   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // UsesSEHTry
2254   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // SkippedBody
2255   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // MultiVersion
2256   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // LateParsed
2257   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
2258   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LocEnd
2259   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32)); // ODRHash
2260   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // TemplateKind
2261   // This Array slurps the rest of the record. Fortunately we want to encode
2262   // (nearly) all the remaining (variable number of) fields in the same way.
2263   //
2264   // This is the function template information if any, then
2265   //         NumParams and Params[] from FunctionDecl, and
2266   //         NumOverriddenMethods, OverriddenMethods[] from CXXMethodDecl.
2267   //
2268   //  Add an AbbrevOp for 'size then elements' and use it here.
2269   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2270   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2271   DeclCXXMethodAbbrev = Stream.EmitAbbrev(std::move(Abv));
2272 
2273   // Abbreviation for EXPR_DECL_REF
2274   Abv = std::make_shared<BitCodeAbbrev>();
2275   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_DECL_REF));
2276   //Stmt
2277   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsOMPStructuredBlock
2278   // Expr
2279   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2280   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2281   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2282   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2283   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2284   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2285   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2286   //DeclRefExpr
2287   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HasQualifier
2288   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //GetDeclFound
2289   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ExplicitTemplateArgs
2290   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HadMultipleCandidates
2291   Abv->Add(BitCodeAbbrevOp(0)); // RefersToEnclosingVariableOrCapture
2292   Abv->Add(BitCodeAbbrevOp(0)); // NonOdrUseReason
2293   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclRef
2294   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2295   DeclRefExprAbbrev = Stream.EmitAbbrev(std::move(Abv));
2296 
2297   // Abbreviation for EXPR_INTEGER_LITERAL
2298   Abv = std::make_shared<BitCodeAbbrev>();
2299   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_INTEGER_LITERAL));
2300   //Stmt
2301   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsOMPStructuredBlock
2302   // Expr
2303   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2304   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2305   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2306   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2307   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2308   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2309   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2310   //Integer Literal
2311   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2312   Abv->Add(BitCodeAbbrevOp(32));                      // Bit Width
2313   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Value
2314   IntegerLiteralAbbrev = Stream.EmitAbbrev(std::move(Abv));
2315 
2316   // Abbreviation for EXPR_CHARACTER_LITERAL
2317   Abv = std::make_shared<BitCodeAbbrev>();
2318   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_CHARACTER_LITERAL));
2319   //Stmt
2320   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsOMPStructuredBlock
2321   // Expr
2322   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2323   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2324   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2325   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2326   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2327   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2328   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2329   //Character Literal
2330   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getValue
2331   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2332   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // getKind
2333   CharacterLiteralAbbrev = Stream.EmitAbbrev(std::move(Abv));
2334 
2335   // Abbreviation for EXPR_IMPLICIT_CAST
2336   Abv = std::make_shared<BitCodeAbbrev>();
2337   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_IMPLICIT_CAST));
2338   // Stmt
2339   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsOMPStructuredBlock
2340   // Expr
2341   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2342   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2343   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2344   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2345   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2346   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2347   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2348   // CastExpr
2349   Abv->Add(BitCodeAbbrevOp(0)); // PathSize
2350   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 6)); // CastKind
2351   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // PartOfExplicitCast
2352   // ImplicitCastExpr
2353   ExprImplicitCastAbbrev = Stream.EmitAbbrev(std::move(Abv));
2354 
2355   Abv = std::make_shared<BitCodeAbbrev>();
2356   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_LEXICAL));
2357   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2358   DeclContextLexicalAbbrev = Stream.EmitAbbrev(std::move(Abv));
2359 
2360   Abv = std::make_shared<BitCodeAbbrev>();
2361   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_VISIBLE));
2362   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2363   DeclContextVisibleLookupAbbrev = Stream.EmitAbbrev(std::move(Abv));
2364 }
2365 
2366 /// isRequiredDecl - Check if this is a "required" Decl, which must be seen by
2367 /// consumers of the AST.
2368 ///
2369 /// Such decls will always be deserialized from the AST file, so we would like
2370 /// this to be as restrictive as possible. Currently the predicate is driven by
2371 /// code generation requirements, if other clients have a different notion of
2372 /// what is "required" then we may have to consider an alternate scheme where
2373 /// clients can iterate over the top-level decls and get information on them,
2374 /// without necessary deserializing them. We could explicitly require such
2375 /// clients to use a separate API call to "realize" the decl. This should be
2376 /// relatively painless since they would presumably only do it for top-level
2377 /// decls.
2378 static bool isRequiredDecl(const Decl *D, ASTContext &Context,
2379                            bool WritingModule) {
2380   // An ObjCMethodDecl is never considered as "required" because its
2381   // implementation container always is.
2382 
2383   // File scoped assembly or obj-c or OMP declare target implementation must be
2384   // seen.
2385   if (isa<FileScopeAsmDecl>(D) || isa<ObjCImplDecl>(D))
2386     return true;
2387 
2388   if (WritingModule && isPartOfPerModuleInitializer(D)) {
2389     // These declarations are part of the module initializer, and are emitted
2390     // if and when the module is imported, rather than being emitted eagerly.
2391     return false;
2392   }
2393 
2394   return Context.DeclMustBeEmitted(D);
2395 }
2396 
2397 void ASTWriter::WriteDecl(ASTContext &Context, Decl *D) {
2398   PrettyDeclStackTraceEntry CrashInfo(Context, D, SourceLocation(),
2399                                       "serializing");
2400 
2401   // Determine the ID for this declaration.
2402   serialization::DeclID ID;
2403   assert(!D->isFromASTFile() && "should not be emitting imported decl");
2404   serialization::DeclID &IDR = DeclIDs[D];
2405   if (IDR == 0)
2406     IDR = NextDeclID++;
2407 
2408   ID = IDR;
2409 
2410   assert(ID >= FirstDeclID && "invalid decl ID");
2411 
2412   RecordData Record;
2413   ASTDeclWriter W(*this, Context, Record);
2414 
2415   // Build a record for this declaration
2416   W.Visit(D);
2417 
2418   // Emit this declaration to the bitstream.
2419   uint64_t Offset = W.Emit(D);
2420 
2421   // Record the offset for this declaration
2422   SourceLocation Loc = D->getLocation();
2423   unsigned Index = ID - FirstDeclID;
2424   if (DeclOffsets.size() == Index)
2425     DeclOffsets.push_back(DeclOffset(Loc, Offset));
2426   else if (DeclOffsets.size() < Index) {
2427     // FIXME: Can/should this happen?
2428     DeclOffsets.resize(Index+1);
2429     DeclOffsets[Index].setLocation(Loc);
2430     DeclOffsets[Index].BitOffset = Offset;
2431   } else {
2432     llvm_unreachable("declarations should be emitted in ID order");
2433   }
2434 
2435   SourceManager &SM = Context.getSourceManager();
2436   if (Loc.isValid() && SM.isLocalSourceLocation(Loc))
2437     associateDeclWithFile(D, ID);
2438 
2439   // Note declarations that should be deserialized eagerly so that we can add
2440   // them to a record in the AST file later.
2441   if (isRequiredDecl(D, Context, WritingModule))
2442     EagerlyDeserializedDecls.push_back(ID);
2443 }
2444 
2445 void ASTRecordWriter::AddFunctionDefinition(const FunctionDecl *FD) {
2446   // Switch case IDs are per function body.
2447   Writer->ClearSwitchCaseIDs();
2448 
2449   assert(FD->doesThisDeclarationHaveABody());
2450   bool ModulesCodegen = false;
2451   if (Writer->WritingModule && !FD->isDependentContext()) {
2452     Optional<GVALinkage> Linkage;
2453     if (Writer->WritingModule->Kind == Module::ModuleInterfaceUnit) {
2454       // When building a C++ Modules TS module interface unit, a strong
2455       // definition in the module interface is provided by the compilation of
2456       // that module interface unit, not by its users. (Inline functions are
2457       // still emitted in module users.)
2458       Linkage = Writer->Context->GetGVALinkageForFunction(FD);
2459       ModulesCodegen = *Linkage == GVA_StrongExternal;
2460     }
2461     if (Writer->Context->getLangOpts().ModulesCodegen) {
2462       // Under -fmodules-codegen, codegen is performed for all non-internal,
2463       // non-always_inline functions, unless they are available elsewhere.
2464       if (!FD->hasAttr<AlwaysInlineAttr>()) {
2465         if (!Linkage)
2466           Linkage = Writer->Context->GetGVALinkageForFunction(FD);
2467         ModulesCodegen =
2468             *Linkage != GVA_Internal && *Linkage != GVA_AvailableExternally;
2469       }
2470     }
2471   }
2472   Record->push_back(ModulesCodegen);
2473   if (ModulesCodegen)
2474     Writer->ModularCodegenDecls.push_back(Writer->GetDeclRef(FD));
2475   if (auto *CD = dyn_cast<CXXConstructorDecl>(FD)) {
2476     Record->push_back(CD->getNumCtorInitializers());
2477     if (CD->getNumCtorInitializers())
2478       AddCXXCtorInitializers(
2479           llvm::makeArrayRef(CD->init_begin(), CD->init_end()));
2480   }
2481   AddStmt(FD->getBody());
2482 }
2483