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/DeclCXX.h"
15 #include "clang/AST/DeclContextInternals.h"
16 #include "clang/AST/DeclTemplate.h"
17 #include "clang/AST/DeclVisitor.h"
18 #include "clang/AST/Expr.h"
19 #include "clang/AST/OpenMPClause.h"
20 #include "clang/AST/PrettyDeclStackTrace.h"
21 #include "clang/Basic/SourceManager.h"
22 #include "clang/Serialization/ASTReader.h"
23 #include "clang/Serialization/ASTWriter.h"
24 #include "llvm/Bitstream/BitstreamWriter.h"
25 #include "llvm/Support/ErrorHandling.h"
26 using namespace clang;
27 using namespace serialization;
28 
29 //===----------------------------------------------------------------------===//
30 // Declaration serialization
31 //===----------------------------------------------------------------------===//
32 
33 namespace clang {
34   class ASTDeclWriter : public DeclVisitor<ASTDeclWriter, void> {
35     ASTWriter &Writer;
36     ASTContext &Context;
37     ASTRecordWriter Record;
38 
39     serialization::DeclCode Code;
40     unsigned AbbrevToUse;
41 
42   public:
43     ASTDeclWriter(ASTWriter &Writer, ASTContext &Context,
44                   ASTWriter::RecordDataImpl &Record)
45         : Writer(Writer), Context(Context), Record(Writer, Record),
46           Code((serialization::DeclCode)0), AbbrevToUse(0) {}
47 
48     uint64_t Emit(Decl *D) {
49       if (!Code)
50         llvm::report_fatal_error(StringRef("unexpected declaration kind '") +
51             D->getDeclKindName() + "'");
52       return Record.Emit(Code, AbbrevToUse);
53     }
54 
55     void Visit(Decl *D);
56 
57     void VisitDecl(Decl *D);
58     void VisitPragmaCommentDecl(PragmaCommentDecl *D);
59     void VisitPragmaDetectMismatchDecl(PragmaDetectMismatchDecl *D);
60     void VisitTranslationUnitDecl(TranslationUnitDecl *D);
61     void VisitNamedDecl(NamedDecl *D);
62     void VisitLabelDecl(LabelDecl *LD);
63     void VisitNamespaceDecl(NamespaceDecl *D);
64     void VisitUsingDirectiveDecl(UsingDirectiveDecl *D);
65     void VisitNamespaceAliasDecl(NamespaceAliasDecl *D);
66     void VisitTypeDecl(TypeDecl *D);
67     void VisitTypedefNameDecl(TypedefNameDecl *D);
68     void VisitTypedefDecl(TypedefDecl *D);
69     void VisitTypeAliasDecl(TypeAliasDecl *D);
70     void VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D);
71     void VisitTagDecl(TagDecl *D);
72     void VisitEnumDecl(EnumDecl *D);
73     void VisitRecordDecl(RecordDecl *D);
74     void VisitCXXRecordDecl(CXXRecordDecl *D);
75     void VisitClassTemplateSpecializationDecl(
76                                             ClassTemplateSpecializationDecl *D);
77     void VisitClassTemplatePartialSpecializationDecl(
78                                      ClassTemplatePartialSpecializationDecl *D);
79     void VisitVarTemplateSpecializationDecl(VarTemplateSpecializationDecl *D);
80     void VisitVarTemplatePartialSpecializationDecl(
81         VarTemplatePartialSpecializationDecl *D);
82     void VisitClassScopeFunctionSpecializationDecl(
83                                        ClassScopeFunctionSpecializationDecl *D);
84     void VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
85     void VisitValueDecl(ValueDecl *D);
86     void VisitEnumConstantDecl(EnumConstantDecl *D);
87     void VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D);
88     void VisitDeclaratorDecl(DeclaratorDecl *D);
89     void VisitFunctionDecl(FunctionDecl *D);
90     void VisitCXXDeductionGuideDecl(CXXDeductionGuideDecl *D);
91     void VisitCXXMethodDecl(CXXMethodDecl *D);
92     void VisitCXXConstructorDecl(CXXConstructorDecl *D);
93     void VisitCXXDestructorDecl(CXXDestructorDecl *D);
94     void VisitCXXConversionDecl(CXXConversionDecl *D);
95     void VisitFieldDecl(FieldDecl *D);
96     void VisitMSPropertyDecl(MSPropertyDecl *D);
97     void VisitIndirectFieldDecl(IndirectFieldDecl *D);
98     void VisitVarDecl(VarDecl *D);
99     void VisitImplicitParamDecl(ImplicitParamDecl *D);
100     void VisitParmVarDecl(ParmVarDecl *D);
101     void VisitDecompositionDecl(DecompositionDecl *D);
102     void VisitBindingDecl(BindingDecl *D);
103     void VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
104     void VisitTemplateDecl(TemplateDecl *D);
105     void VisitConceptDecl(ConceptDecl *D);
106     void VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D);
107     void VisitClassTemplateDecl(ClassTemplateDecl *D);
108     void VisitVarTemplateDecl(VarTemplateDecl *D);
109     void VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
110     void VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
111     void VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D);
112     void VisitUsingDecl(UsingDecl *D);
113     void VisitUsingPackDecl(UsingPackDecl *D);
114     void VisitUsingShadowDecl(UsingShadowDecl *D);
115     void VisitConstructorUsingShadowDecl(ConstructorUsingShadowDecl *D);
116     void VisitLinkageSpecDecl(LinkageSpecDecl *D);
117     void VisitExportDecl(ExportDecl *D);
118     void VisitFileScopeAsmDecl(FileScopeAsmDecl *D);
119     void VisitImportDecl(ImportDecl *D);
120     void VisitAccessSpecDecl(AccessSpecDecl *D);
121     void VisitFriendDecl(FriendDecl *D);
122     void VisitFriendTemplateDecl(FriendTemplateDecl *D);
123     void VisitStaticAssertDecl(StaticAssertDecl *D);
124     void VisitBlockDecl(BlockDecl *D);
125     void VisitCapturedDecl(CapturedDecl *D);
126     void VisitEmptyDecl(EmptyDecl *D);
127     void VisitLifetimeExtendedTemporaryDecl(LifetimeExtendedTemporaryDecl *D);
128 
129     void VisitDeclContext(DeclContext *DC);
130     template <typename T> void VisitRedeclarable(Redeclarable<T> *D);
131 
132 
133     // FIXME: Put in the same order is DeclNodes.td?
134     void VisitObjCMethodDecl(ObjCMethodDecl *D);
135     void VisitObjCTypeParamDecl(ObjCTypeParamDecl *D);
136     void VisitObjCContainerDecl(ObjCContainerDecl *D);
137     void VisitObjCInterfaceDecl(ObjCInterfaceDecl *D);
138     void VisitObjCIvarDecl(ObjCIvarDecl *D);
139     void VisitObjCProtocolDecl(ObjCProtocolDecl *D);
140     void VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D);
141     void VisitObjCCategoryDecl(ObjCCategoryDecl *D);
142     void VisitObjCImplDecl(ObjCImplDecl *D);
143     void VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D);
144     void VisitObjCImplementationDecl(ObjCImplementationDecl *D);
145     void VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D);
146     void VisitObjCPropertyDecl(ObjCPropertyDecl *D);
147     void VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D);
148     void VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D);
149     void VisitOMPAllocateDecl(OMPAllocateDecl *D);
150     void VisitOMPRequiresDecl(OMPRequiresDecl *D);
151     void VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D);
152     void VisitOMPDeclareMapperDecl(OMPDeclareMapperDecl *D);
153     void VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D);
154 
155     /// Add an Objective-C type parameter list to the given record.
156     void AddObjCTypeParamList(ObjCTypeParamList *typeParams) {
157       // Empty type parameter list.
158       if (!typeParams) {
159         Record.push_back(0);
160         return;
161       }
162 
163       Record.push_back(typeParams->size());
164       for (auto typeParam : *typeParams) {
165         Record.AddDeclRef(typeParam);
166       }
167       Record.AddSourceLocation(typeParams->getLAngleLoc());
168       Record.AddSourceLocation(typeParams->getRAngleLoc());
169     }
170 
171     /// Add to the record the first declaration from each module file that
172     /// provides a declaration of D. The intent is to provide a sufficient
173     /// set such that reloading this set will load all current redeclarations.
174     void AddFirstDeclFromEachModule(const Decl *D, bool IncludeLocal) {
175       llvm::MapVector<ModuleFile*, const Decl*> Firsts;
176       // FIXME: We can skip entries that we know are implied by others.
177       for (const Decl *R = D->getMostRecentDecl(); R; R = R->getPreviousDecl()) {
178         if (R->isFromASTFile())
179           Firsts[Writer.Chain->getOwningModuleFile(R)] = R;
180         else if (IncludeLocal)
181           Firsts[nullptr] = R;
182       }
183       for (const auto &F : Firsts)
184         Record.AddDeclRef(F.second);
185     }
186 
187     /// Get the specialization decl from an entry in the specialization list.
188     template <typename EntryType>
189     typename RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::DeclType *
190     getSpecializationDecl(EntryType &T) {
191       return RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::getDecl(&T);
192     }
193 
194     /// Get the list of partial specializations from a template's common ptr.
195     template<typename T>
196     decltype(T::PartialSpecializations) &getPartialSpecializations(T *Common) {
197       return Common->PartialSpecializations;
198     }
199     ArrayRef<Decl> getPartialSpecializations(FunctionTemplateDecl::Common *) {
200       return None;
201     }
202 
203     template<typename DeclTy>
204     void AddTemplateSpecializations(DeclTy *D) {
205       auto *Common = D->getCommonPtr();
206 
207       // If we have any lazy specializations, and the external AST source is
208       // our chained AST reader, we can just write out the DeclIDs. Otherwise,
209       // we need to resolve them to actual declarations.
210       if (Writer.Chain != Writer.Context->getExternalSource() &&
211           Common->LazySpecializations) {
212         D->LoadLazySpecializations();
213         assert(!Common->LazySpecializations);
214       }
215 
216       ArrayRef<DeclID> LazySpecializations;
217       if (auto *LS = Common->LazySpecializations)
218         LazySpecializations = llvm::makeArrayRef(LS + 1, LS[0]);
219 
220       // Add a slot to the record for the number of specializations.
221       unsigned I = Record.size();
222       Record.push_back(0);
223 
224       // AddFirstDeclFromEachModule might trigger deserialization, invalidating
225       // *Specializations iterators.
226       llvm::SmallVector<const Decl*, 16> Specs;
227       for (auto &Entry : Common->Specializations)
228         Specs.push_back(getSpecializationDecl(Entry));
229       for (auto &Entry : getPartialSpecializations(Common))
230         Specs.push_back(getSpecializationDecl(Entry));
231 
232       for (auto *D : Specs) {
233         assert(D->isCanonicalDecl() && "non-canonical decl in set");
234         AddFirstDeclFromEachModule(D, /*IncludeLocal*/true);
235       }
236       Record.append(LazySpecializations.begin(), LazySpecializations.end());
237 
238       // Update the size entry we added earlier.
239       Record[I] = Record.size() - I - 1;
240     }
241 
242     /// Ensure that this template specialization is associated with the specified
243     /// template on reload.
244     void RegisterTemplateSpecialization(const Decl *Template,
245                                         const Decl *Specialization) {
246       Template = Template->getCanonicalDecl();
247 
248       // If the canonical template is local, we'll write out this specialization
249       // when we emit it.
250       // FIXME: We can do the same thing if there is any local declaration of
251       // the template, to avoid emitting an update record.
252       if (!Template->isFromASTFile())
253         return;
254 
255       // We only need to associate the first local declaration of the
256       // specialization. The other declarations will get pulled in by it.
257       if (Writer.getFirstLocalDecl(Specialization) != Specialization)
258         return;
259 
260       Writer.DeclUpdates[Template].push_back(ASTWriter::DeclUpdate(
261           UPD_CXX_ADDED_TEMPLATE_SPECIALIZATION, Specialization));
262     }
263   };
264 }
265 
266 void ASTDeclWriter::Visit(Decl *D) {
267   DeclVisitor<ASTDeclWriter>::Visit(D);
268 
269   // Source locations require array (variable-length) abbreviations.  The
270   // abbreviation infrastructure requires that arrays are encoded last, so
271   // we handle it here in the case of those classes derived from DeclaratorDecl
272   if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D)) {
273     if (auto *TInfo = DD->getTypeSourceInfo())
274       Record.AddTypeLoc(TInfo->getTypeLoc());
275   }
276 
277   // Handle FunctionDecl's body here and write it after all other Stmts/Exprs
278   // have been written. We want it last because we will not read it back when
279   // retrieving it from the AST, we'll just lazily set the offset.
280   if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
281     Record.push_back(FD->doesThisDeclarationHaveABody());
282     if (FD->doesThisDeclarationHaveABody())
283       Record.AddFunctionDefinition(FD);
284   }
285 
286   // If this declaration is also a DeclContext, write blocks for the
287   // declarations that lexically stored inside its context and those
288   // declarations that are visible from its context.
289   if (DeclContext *DC = dyn_cast<DeclContext>(D))
290     VisitDeclContext(DC);
291 }
292 
293 void ASTDeclWriter::VisitDecl(Decl *D) {
294   Record.AddDeclRef(cast_or_null<Decl>(D->getDeclContext()));
295   if (D->getDeclContext() != D->getLexicalDeclContext())
296     Record.AddDeclRef(cast_or_null<Decl>(D->getLexicalDeclContext()));
297   else
298     Record.push_back(0);
299   Record.push_back(D->isInvalidDecl());
300   Record.push_back(D->hasAttrs());
301   if (D->hasAttrs())
302     Record.AddAttributes(D->getAttrs());
303   Record.push_back(D->isImplicit());
304   Record.push_back(D->isUsed(false));
305   Record.push_back(D->isReferenced());
306   Record.push_back(D->isTopLevelDeclInObjCContainer());
307   Record.push_back(D->getAccess());
308   Record.push_back(D->isModulePrivate());
309   Record.push_back(Writer.getSubmoduleID(D->getOwningModule()));
310 
311   // If this declaration injected a name into a context different from its
312   // lexical context, and that context is an imported namespace, we need to
313   // update its visible declarations to include this name.
314   //
315   // This happens when we instantiate a class with a friend declaration or a
316   // function with a local extern declaration, for instance.
317   //
318   // FIXME: Can we handle this in AddedVisibleDecl instead?
319   if (D->isOutOfLine()) {
320     auto *DC = D->getDeclContext();
321     while (auto *NS = dyn_cast<NamespaceDecl>(DC->getRedeclContext())) {
322       if (!NS->isFromASTFile())
323         break;
324       Writer.UpdatedDeclContexts.insert(NS->getPrimaryContext());
325       if (!NS->isInlineNamespace())
326         break;
327       DC = NS->getParent();
328     }
329   }
330 }
331 
332 void ASTDeclWriter::VisitPragmaCommentDecl(PragmaCommentDecl *D) {
333   StringRef Arg = D->getArg();
334   Record.push_back(Arg.size());
335   VisitDecl(D);
336   Record.AddSourceLocation(D->getBeginLoc());
337   Record.push_back(D->getCommentKind());
338   Record.AddString(Arg);
339   Code = serialization::DECL_PRAGMA_COMMENT;
340 }
341 
342 void ASTDeclWriter::VisitPragmaDetectMismatchDecl(
343     PragmaDetectMismatchDecl *D) {
344   StringRef Name = D->getName();
345   StringRef Value = D->getValue();
346   Record.push_back(Name.size() + 1 + Value.size());
347   VisitDecl(D);
348   Record.AddSourceLocation(D->getBeginLoc());
349   Record.AddString(Name);
350   Record.AddString(Value);
351   Code = serialization::DECL_PRAGMA_DETECT_MISMATCH;
352 }
353 
354 void ASTDeclWriter::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
355   llvm_unreachable("Translation units aren't directly serialized");
356 }
357 
358 void ASTDeclWriter::VisitNamedDecl(NamedDecl *D) {
359   VisitDecl(D);
360   Record.AddDeclarationName(D->getDeclName());
361   Record.push_back(needsAnonymousDeclarationNumber(D)
362                        ? Writer.getAnonymousDeclarationNumber(D)
363                        : 0);
364 }
365 
366 void ASTDeclWriter::VisitTypeDecl(TypeDecl *D) {
367   VisitNamedDecl(D);
368   Record.AddSourceLocation(D->getBeginLoc());
369   Record.AddTypeRef(QualType(D->getTypeForDecl(), 0));
370 }
371 
372 void ASTDeclWriter::VisitTypedefNameDecl(TypedefNameDecl *D) {
373   VisitRedeclarable(D);
374   VisitTypeDecl(D);
375   Record.AddTypeSourceInfo(D->getTypeSourceInfo());
376   Record.push_back(D->isModed());
377   if (D->isModed())
378     Record.AddTypeRef(D->getUnderlyingType());
379   Record.AddDeclRef(D->getAnonDeclWithTypedefName(false));
380 }
381 
382 void ASTDeclWriter::VisitTypedefDecl(TypedefDecl *D) {
383   VisitTypedefNameDecl(D);
384   if (D->getDeclContext() == D->getLexicalDeclContext() &&
385       !D->hasAttrs() &&
386       !D->isImplicit() &&
387       D->getFirstDecl() == D->getMostRecentDecl() &&
388       !D->isInvalidDecl() &&
389       !D->isTopLevelDeclInObjCContainer() &&
390       !D->isModulePrivate() &&
391       !needsAnonymousDeclarationNumber(D) &&
392       D->getDeclName().getNameKind() == DeclarationName::Identifier)
393     AbbrevToUse = Writer.getDeclTypedefAbbrev();
394 
395   Code = serialization::DECL_TYPEDEF;
396 }
397 
398 void ASTDeclWriter::VisitTypeAliasDecl(TypeAliasDecl *D) {
399   VisitTypedefNameDecl(D);
400   Record.AddDeclRef(D->getDescribedAliasTemplate());
401   Code = serialization::DECL_TYPEALIAS;
402 }
403 
404 void ASTDeclWriter::VisitTagDecl(TagDecl *D) {
405   VisitRedeclarable(D);
406   VisitTypeDecl(D);
407   Record.push_back(D->getIdentifierNamespace());
408   Record.push_back((unsigned)D->getTagKind()); // FIXME: stable encoding
409   if (!isa<CXXRecordDecl>(D))
410     Record.push_back(D->isCompleteDefinition());
411   Record.push_back(D->isEmbeddedInDeclarator());
412   Record.push_back(D->isFreeStanding());
413   Record.push_back(D->isCompleteDefinitionRequired());
414   Record.AddSourceRange(D->getBraceRange());
415 
416   if (D->hasExtInfo()) {
417     Record.push_back(1);
418     Record.AddQualifierInfo(*D->getExtInfo());
419   } else if (auto *TD = D->getTypedefNameForAnonDecl()) {
420     Record.push_back(2);
421     Record.AddDeclRef(TD);
422     Record.AddIdentifierRef(TD->getDeclName().getAsIdentifierInfo());
423   } else {
424     Record.push_back(0);
425   }
426 }
427 
428 void ASTDeclWriter::VisitEnumDecl(EnumDecl *D) {
429   VisitTagDecl(D);
430   Record.AddTypeSourceInfo(D->getIntegerTypeSourceInfo());
431   if (!D->getIntegerTypeSourceInfo())
432     Record.AddTypeRef(D->getIntegerType());
433   Record.AddTypeRef(D->getPromotionType());
434   Record.push_back(D->getNumPositiveBits());
435   Record.push_back(D->getNumNegativeBits());
436   Record.push_back(D->isScoped());
437   Record.push_back(D->isScopedUsingClassTag());
438   Record.push_back(D->isFixed());
439   Record.push_back(D->getODRHash());
440 
441   if (MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo()) {
442     Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
443     Record.push_back(MemberInfo->getTemplateSpecializationKind());
444     Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
445   } else {
446     Record.AddDeclRef(nullptr);
447   }
448 
449   if (D->getDeclContext() == D->getLexicalDeclContext() &&
450       !D->hasAttrs() &&
451       !D->isImplicit() &&
452       !D->isUsed(false) &&
453       !D->hasExtInfo() &&
454       !D->getTypedefNameForAnonDecl() &&
455       D->getFirstDecl() == D->getMostRecentDecl() &&
456       !D->isInvalidDecl() &&
457       !D->isReferenced() &&
458       !D->isTopLevelDeclInObjCContainer() &&
459       D->getAccess() == AS_none &&
460       !D->isModulePrivate() &&
461       !CXXRecordDecl::classofKind(D->getKind()) &&
462       !D->getIntegerTypeSourceInfo() &&
463       !D->getMemberSpecializationInfo() &&
464       !needsAnonymousDeclarationNumber(D) &&
465       D->getDeclName().getNameKind() == DeclarationName::Identifier)
466     AbbrevToUse = Writer.getDeclEnumAbbrev();
467 
468   Code = serialization::DECL_ENUM;
469 }
470 
471 void ASTDeclWriter::VisitRecordDecl(RecordDecl *D) {
472   VisitTagDecl(D);
473   Record.push_back(D->hasFlexibleArrayMember());
474   Record.push_back(D->isAnonymousStructOrUnion());
475   Record.push_back(D->hasObjectMember());
476   Record.push_back(D->hasVolatileMember());
477   Record.push_back(D->isNonTrivialToPrimitiveDefaultInitialize());
478   Record.push_back(D->isNonTrivialToPrimitiveCopy());
479   Record.push_back(D->isNonTrivialToPrimitiveDestroy());
480   Record.push_back(D->hasNonTrivialToPrimitiveDefaultInitializeCUnion());
481   Record.push_back(D->hasNonTrivialToPrimitiveDestructCUnion());
482   Record.push_back(D->hasNonTrivialToPrimitiveCopyCUnion());
483   Record.push_back(D->isParamDestroyedInCallee());
484   Record.push_back(D->getArgPassingRestrictions());
485 
486   if (D->getDeclContext() == D->getLexicalDeclContext() &&
487       !D->hasAttrs() &&
488       !D->isImplicit() &&
489       !D->isUsed(false) &&
490       !D->hasExtInfo() &&
491       !D->getTypedefNameForAnonDecl() &&
492       D->getFirstDecl() == D->getMostRecentDecl() &&
493       !D->isInvalidDecl() &&
494       !D->isReferenced() &&
495       !D->isTopLevelDeclInObjCContainer() &&
496       D->getAccess() == AS_none &&
497       !D->isModulePrivate() &&
498       !CXXRecordDecl::classofKind(D->getKind()) &&
499       !needsAnonymousDeclarationNumber(D) &&
500       D->getDeclName().getNameKind() == DeclarationName::Identifier)
501     AbbrevToUse = Writer.getDeclRecordAbbrev();
502 
503   Code = serialization::DECL_RECORD;
504 }
505 
506 void ASTDeclWriter::VisitValueDecl(ValueDecl *D) {
507   VisitNamedDecl(D);
508   Record.AddTypeRef(D->getType());
509 }
510 
511 void ASTDeclWriter::VisitEnumConstantDecl(EnumConstantDecl *D) {
512   VisitValueDecl(D);
513   Record.push_back(D->getInitExpr()? 1 : 0);
514   if (D->getInitExpr())
515     Record.AddStmt(D->getInitExpr());
516   Record.AddAPSInt(D->getInitVal());
517 
518   Code = serialization::DECL_ENUM_CONSTANT;
519 }
520 
521 void ASTDeclWriter::VisitDeclaratorDecl(DeclaratorDecl *D) {
522   VisitValueDecl(D);
523   Record.AddSourceLocation(D->getInnerLocStart());
524   Record.push_back(D->hasExtInfo());
525   if (D->hasExtInfo())
526     Record.AddQualifierInfo(*D->getExtInfo());
527   // The location information is deferred until the end of the record.
528   Record.AddTypeRef(D->getTypeSourceInfo() ? D->getTypeSourceInfo()->getType()
529                                            : QualType());
530 }
531 
532 void ASTDeclWriter::VisitFunctionDecl(FunctionDecl *D) {
533   VisitRedeclarable(D);
534   VisitDeclaratorDecl(D);
535   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
536   Record.push_back(D->getIdentifierNamespace());
537 
538   // FunctionDecl's body is handled last at ASTWriterDecl::Visit,
539   // after everything else is written.
540   Record.push_back(static_cast<int>(D->getStorageClass())); // FIXME: stable encoding
541   Record.push_back(D->isInlineSpecified());
542   Record.push_back(D->isInlined());
543   Record.push_back(D->isVirtualAsWritten());
544   Record.push_back(D->isPure());
545   Record.push_back(D->hasInheritedPrototype());
546   Record.push_back(D->hasWrittenPrototype());
547   Record.push_back(D->isDeletedBit());
548   Record.push_back(D->isTrivial());
549   Record.push_back(D->isTrivialForCall());
550   Record.push_back(D->isDefaulted());
551   Record.push_back(D->isExplicitlyDefaulted());
552   Record.push_back(D->hasImplicitReturnZero());
553   Record.push_back(D->getConstexprKind());
554   Record.push_back(D->usesSEHTry());
555   Record.push_back(D->hasSkippedBody());
556   Record.push_back(D->isMultiVersion());
557   Record.push_back(D->isLateTemplateParsed());
558   Record.push_back(D->getLinkageInternal());
559   Record.AddSourceLocation(D->getEndLoc());
560 
561   Record.push_back(D->getODRHash());
562   Record.push_back(D->usesFPIntrin());
563 
564   Record.push_back(D->getTemplatedKind());
565   switch (D->getTemplatedKind()) {
566   case FunctionDecl::TK_NonTemplate:
567     break;
568   case FunctionDecl::TK_FunctionTemplate:
569     Record.AddDeclRef(D->getDescribedFunctionTemplate());
570     break;
571   case FunctionDecl::TK_MemberSpecialization: {
572     MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo();
573     Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
574     Record.push_back(MemberInfo->getTemplateSpecializationKind());
575     Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
576     break;
577   }
578   case FunctionDecl::TK_FunctionTemplateSpecialization: {
579     FunctionTemplateSpecializationInfo *
580       FTSInfo = D->getTemplateSpecializationInfo();
581 
582     RegisterTemplateSpecialization(FTSInfo->getTemplate(), D);
583 
584     Record.AddDeclRef(FTSInfo->getTemplate());
585     Record.push_back(FTSInfo->getTemplateSpecializationKind());
586 
587     // Template arguments.
588     Record.AddTemplateArgumentList(FTSInfo->TemplateArguments);
589 
590     // Template args as written.
591     Record.push_back(FTSInfo->TemplateArgumentsAsWritten != nullptr);
592     if (FTSInfo->TemplateArgumentsAsWritten) {
593       Record.push_back(FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs);
594       for (int i=0, e = FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs;
595              i!=e; ++i)
596         Record.AddTemplateArgumentLoc(
597             (*FTSInfo->TemplateArgumentsAsWritten)[i]);
598       Record.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->LAngleLoc);
599       Record.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->RAngleLoc);
600     }
601 
602     Record.AddSourceLocation(FTSInfo->getPointOfInstantiation());
603 
604     if (MemberSpecializationInfo *MemberInfo =
605         FTSInfo->getMemberSpecializationInfo()) {
606       Record.push_back(1);
607       Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
608       Record.push_back(MemberInfo->getTemplateSpecializationKind());
609       Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
610     } else {
611       Record.push_back(0);
612     }
613 
614     if (D->isCanonicalDecl()) {
615       // Write the template that contains the specializations set. We will
616       // add a FunctionTemplateSpecializationInfo to it when reading.
617       Record.AddDeclRef(FTSInfo->getTemplate()->getCanonicalDecl());
618     }
619     break;
620   }
621   case FunctionDecl::TK_DependentFunctionTemplateSpecialization: {
622     DependentFunctionTemplateSpecializationInfo *
623       DFTSInfo = D->getDependentSpecializationInfo();
624 
625     // Templates.
626     Record.push_back(DFTSInfo->getNumTemplates());
627     for (int i=0, e = DFTSInfo->getNumTemplates(); i != e; ++i)
628       Record.AddDeclRef(DFTSInfo->getTemplate(i));
629 
630     // Templates args.
631     Record.push_back(DFTSInfo->getNumTemplateArgs());
632     for (int i=0, e = DFTSInfo->getNumTemplateArgs(); i != e; ++i)
633       Record.AddTemplateArgumentLoc(DFTSInfo->getTemplateArg(i));
634     Record.AddSourceLocation(DFTSInfo->getLAngleLoc());
635     Record.AddSourceLocation(DFTSInfo->getRAngleLoc());
636     break;
637   }
638   }
639 
640   Record.push_back(D->param_size());
641   for (auto P : D->parameters())
642     Record.AddDeclRef(P);
643   Code = serialization::DECL_FUNCTION;
644 }
645 
646 static void addExplicitSpecifier(ExplicitSpecifier ES,
647                                  ASTRecordWriter &Record) {
648   uint64_t Kind = static_cast<uint64_t>(ES.getKind());
649   Kind = Kind << 1 | static_cast<bool>(ES.getExpr());
650   Record.push_back(Kind);
651   if (ES.getExpr()) {
652     Record.AddStmt(ES.getExpr());
653   }
654 }
655 
656 void ASTDeclWriter::VisitCXXDeductionGuideDecl(CXXDeductionGuideDecl *D) {
657   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
658   VisitFunctionDecl(D);
659   Record.push_back(D->isCopyDeductionCandidate());
660   Code = serialization::DECL_CXX_DEDUCTION_GUIDE;
661 }
662 
663 void ASTDeclWriter::VisitObjCMethodDecl(ObjCMethodDecl *D) {
664   VisitNamedDecl(D);
665   // FIXME: convert to LazyStmtPtr?
666   // Unlike C/C++, method bodies will never be in header files.
667   bool HasBodyStuff = D->getBody() != nullptr     ||
668                       D->getSelfDecl() != nullptr || D->getCmdDecl() != nullptr;
669   Record.push_back(HasBodyStuff);
670   if (HasBodyStuff) {
671     Record.AddStmt(D->getBody());
672     Record.AddDeclRef(D->getSelfDecl());
673     Record.AddDeclRef(D->getCmdDecl());
674   }
675   Record.push_back(D->isInstanceMethod());
676   Record.push_back(D->isVariadic());
677   Record.push_back(D->isPropertyAccessor());
678   Record.push_back(D->isSynthesizedAccessorStub());
679   Record.push_back(D->isDefined());
680   Record.push_back(D->isOverriding());
681   Record.push_back(D->hasSkippedBody());
682 
683   Record.push_back(D->isRedeclaration());
684   Record.push_back(D->hasRedeclaration());
685   if (D->hasRedeclaration()) {
686     assert(Context.getObjCMethodRedeclaration(D));
687     Record.AddDeclRef(Context.getObjCMethodRedeclaration(D));
688   }
689 
690   // FIXME: stable encoding for @required/@optional
691   Record.push_back(D->getImplementationControl());
692   // FIXME: stable encoding for in/out/inout/bycopy/byref/oneway/nullability
693   Record.push_back(D->getObjCDeclQualifier());
694   Record.push_back(D->hasRelatedResultType());
695   Record.AddTypeRef(D->getReturnType());
696   Record.AddTypeSourceInfo(D->getReturnTypeSourceInfo());
697   Record.AddSourceLocation(D->getEndLoc());
698   Record.push_back(D->param_size());
699   for (const auto *P : D->parameters())
700     Record.AddDeclRef(P);
701 
702   Record.push_back(D->getSelLocsKind());
703   unsigned NumStoredSelLocs = D->getNumStoredSelLocs();
704   SourceLocation *SelLocs = D->getStoredSelLocs();
705   Record.push_back(NumStoredSelLocs);
706   for (unsigned i = 0; i != NumStoredSelLocs; ++i)
707     Record.AddSourceLocation(SelLocs[i]);
708 
709   Code = serialization::DECL_OBJC_METHOD;
710 }
711 
712 void ASTDeclWriter::VisitObjCTypeParamDecl(ObjCTypeParamDecl *D) {
713   VisitTypedefNameDecl(D);
714   Record.push_back(D->Variance);
715   Record.push_back(D->Index);
716   Record.AddSourceLocation(D->VarianceLoc);
717   Record.AddSourceLocation(D->ColonLoc);
718 
719   Code = serialization::DECL_OBJC_TYPE_PARAM;
720 }
721 
722 void ASTDeclWriter::VisitObjCContainerDecl(ObjCContainerDecl *D) {
723   VisitNamedDecl(D);
724   Record.AddSourceLocation(D->getAtStartLoc());
725   Record.AddSourceRange(D->getAtEndRange());
726   // Abstract class (no need to define a stable serialization::DECL code).
727 }
728 
729 void ASTDeclWriter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
730   VisitRedeclarable(D);
731   VisitObjCContainerDecl(D);
732   Record.AddTypeRef(QualType(D->getTypeForDecl(), 0));
733   AddObjCTypeParamList(D->TypeParamList);
734 
735   Record.push_back(D->isThisDeclarationADefinition());
736   if (D->isThisDeclarationADefinition()) {
737     // Write the DefinitionData
738     ObjCInterfaceDecl::DefinitionData &Data = D->data();
739 
740     Record.AddTypeSourceInfo(D->getSuperClassTInfo());
741     Record.AddSourceLocation(D->getEndOfDefinitionLoc());
742     Record.push_back(Data.HasDesignatedInitializers);
743 
744     // Write out the protocols that are directly referenced by the @interface.
745     Record.push_back(Data.ReferencedProtocols.size());
746     for (const auto *P : D->protocols())
747       Record.AddDeclRef(P);
748     for (const auto &PL : D->protocol_locs())
749       Record.AddSourceLocation(PL);
750 
751     // Write out the protocols that are transitively referenced.
752     Record.push_back(Data.AllReferencedProtocols.size());
753     for (ObjCList<ObjCProtocolDecl>::iterator
754               P = Data.AllReferencedProtocols.begin(),
755            PEnd = Data.AllReferencedProtocols.end();
756          P != PEnd; ++P)
757       Record.AddDeclRef(*P);
758 
759 
760     if (ObjCCategoryDecl *Cat = D->getCategoryListRaw()) {
761       // Ensure that we write out the set of categories for this class.
762       Writer.ObjCClassesWithCategories.insert(D);
763 
764       // Make sure that the categories get serialized.
765       for (; Cat; Cat = Cat->getNextClassCategoryRaw())
766         (void)Writer.GetDeclRef(Cat);
767     }
768   }
769 
770   Code = serialization::DECL_OBJC_INTERFACE;
771 }
772 
773 void ASTDeclWriter::VisitObjCIvarDecl(ObjCIvarDecl *D) {
774   VisitFieldDecl(D);
775   // FIXME: stable encoding for @public/@private/@protected/@package
776   Record.push_back(D->getAccessControl());
777   Record.push_back(D->getSynthesize());
778 
779   if (D->getDeclContext() == D->getLexicalDeclContext() &&
780       !D->hasAttrs() &&
781       !D->isImplicit() &&
782       !D->isUsed(false) &&
783       !D->isInvalidDecl() &&
784       !D->isReferenced() &&
785       !D->isModulePrivate() &&
786       !D->getBitWidth() &&
787       !D->hasExtInfo() &&
788       D->getDeclName())
789     AbbrevToUse = Writer.getDeclObjCIvarAbbrev();
790 
791   Code = serialization::DECL_OBJC_IVAR;
792 }
793 
794 void ASTDeclWriter::VisitObjCProtocolDecl(ObjCProtocolDecl *D) {
795   VisitRedeclarable(D);
796   VisitObjCContainerDecl(D);
797 
798   Record.push_back(D->isThisDeclarationADefinition());
799   if (D->isThisDeclarationADefinition()) {
800     Record.push_back(D->protocol_size());
801     for (const auto *I : D->protocols())
802       Record.AddDeclRef(I);
803     for (const auto &PL : D->protocol_locs())
804       Record.AddSourceLocation(PL);
805   }
806 
807   Code = serialization::DECL_OBJC_PROTOCOL;
808 }
809 
810 void ASTDeclWriter::VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D) {
811   VisitFieldDecl(D);
812   Code = serialization::DECL_OBJC_AT_DEFS_FIELD;
813 }
814 
815 void ASTDeclWriter::VisitObjCCategoryDecl(ObjCCategoryDecl *D) {
816   VisitObjCContainerDecl(D);
817   Record.AddSourceLocation(D->getCategoryNameLoc());
818   Record.AddSourceLocation(D->getIvarLBraceLoc());
819   Record.AddSourceLocation(D->getIvarRBraceLoc());
820   Record.AddDeclRef(D->getClassInterface());
821   AddObjCTypeParamList(D->TypeParamList);
822   Record.push_back(D->protocol_size());
823   for (const auto *I : D->protocols())
824     Record.AddDeclRef(I);
825   for (const auto &PL : D->protocol_locs())
826     Record.AddSourceLocation(PL);
827   Code = serialization::DECL_OBJC_CATEGORY;
828 }
829 
830 void ASTDeclWriter::VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D) {
831   VisitNamedDecl(D);
832   Record.AddDeclRef(D->getClassInterface());
833   Code = serialization::DECL_OBJC_COMPATIBLE_ALIAS;
834 }
835 
836 void ASTDeclWriter::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
837   VisitNamedDecl(D);
838   Record.AddSourceLocation(D->getAtLoc());
839   Record.AddSourceLocation(D->getLParenLoc());
840   Record.AddTypeRef(D->getType());
841   Record.AddTypeSourceInfo(D->getTypeSourceInfo());
842   // FIXME: stable encoding
843   Record.push_back((unsigned)D->getPropertyAttributes());
844   Record.push_back((unsigned)D->getPropertyAttributesAsWritten());
845   // FIXME: stable encoding
846   Record.push_back((unsigned)D->getPropertyImplementation());
847   Record.AddDeclarationName(D->getGetterName());
848   Record.AddSourceLocation(D->getGetterNameLoc());
849   Record.AddDeclarationName(D->getSetterName());
850   Record.AddSourceLocation(D->getSetterNameLoc());
851   Record.AddDeclRef(D->getGetterMethodDecl());
852   Record.AddDeclRef(D->getSetterMethodDecl());
853   Record.AddDeclRef(D->getPropertyIvarDecl());
854   Code = serialization::DECL_OBJC_PROPERTY;
855 }
856 
857 void ASTDeclWriter::VisitObjCImplDecl(ObjCImplDecl *D) {
858   VisitObjCContainerDecl(D);
859   Record.AddDeclRef(D->getClassInterface());
860   // Abstract class (no need to define a stable serialization::DECL code).
861 }
862 
863 void ASTDeclWriter::VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D) {
864   VisitObjCImplDecl(D);
865   Record.AddSourceLocation(D->getCategoryNameLoc());
866   Code = serialization::DECL_OBJC_CATEGORY_IMPL;
867 }
868 
869 void ASTDeclWriter::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
870   VisitObjCImplDecl(D);
871   Record.AddDeclRef(D->getSuperClass());
872   Record.AddSourceLocation(D->getSuperClassLoc());
873   Record.AddSourceLocation(D->getIvarLBraceLoc());
874   Record.AddSourceLocation(D->getIvarRBraceLoc());
875   Record.push_back(D->hasNonZeroConstructors());
876   Record.push_back(D->hasDestructors());
877   Record.push_back(D->NumIvarInitializers);
878   if (D->NumIvarInitializers)
879     Record.AddCXXCtorInitializers(
880         llvm::makeArrayRef(D->init_begin(), D->init_end()));
881   Code = serialization::DECL_OBJC_IMPLEMENTATION;
882 }
883 
884 void ASTDeclWriter::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
885   VisitDecl(D);
886   Record.AddSourceLocation(D->getBeginLoc());
887   Record.AddDeclRef(D->getPropertyDecl());
888   Record.AddDeclRef(D->getPropertyIvarDecl());
889   Record.AddSourceLocation(D->getPropertyIvarDeclLoc());
890   Record.AddDeclRef(D->getGetterMethodDecl());
891   Record.AddDeclRef(D->getSetterMethodDecl());
892   Record.AddStmt(D->getGetterCXXConstructor());
893   Record.AddStmt(D->getSetterCXXAssignment());
894   Code = serialization::DECL_OBJC_PROPERTY_IMPL;
895 }
896 
897 void ASTDeclWriter::VisitFieldDecl(FieldDecl *D) {
898   VisitDeclaratorDecl(D);
899   Record.push_back(D->isMutable());
900 
901   FieldDecl::InitStorageKind ISK = D->InitStorage.getInt();
902   Record.push_back(ISK);
903   if (ISK == FieldDecl::ISK_CapturedVLAType)
904     Record.AddTypeRef(QualType(D->getCapturedVLAType(), 0));
905   else if (ISK)
906     Record.AddStmt(D->getInClassInitializer());
907 
908   Record.AddStmt(D->getBitWidth());
909 
910   if (!D->getDeclName())
911     Record.AddDeclRef(Context.getInstantiatedFromUnnamedFieldDecl(D));
912 
913   if (D->getDeclContext() == D->getLexicalDeclContext() &&
914       !D->hasAttrs() &&
915       !D->isImplicit() &&
916       !D->isUsed(false) &&
917       !D->isInvalidDecl() &&
918       !D->isReferenced() &&
919       !D->isTopLevelDeclInObjCContainer() &&
920       !D->isModulePrivate() &&
921       !D->getBitWidth() &&
922       !D->hasInClassInitializer() &&
923       !D->hasCapturedVLAType() &&
924       !D->hasExtInfo() &&
925       !ObjCIvarDecl::classofKind(D->getKind()) &&
926       !ObjCAtDefsFieldDecl::classofKind(D->getKind()) &&
927       D->getDeclName())
928     AbbrevToUse = Writer.getDeclFieldAbbrev();
929 
930   Code = serialization::DECL_FIELD;
931 }
932 
933 void ASTDeclWriter::VisitMSPropertyDecl(MSPropertyDecl *D) {
934   VisitDeclaratorDecl(D);
935   Record.AddIdentifierRef(D->getGetterId());
936   Record.AddIdentifierRef(D->getSetterId());
937   Code = serialization::DECL_MS_PROPERTY;
938 }
939 
940 void ASTDeclWriter::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
941   VisitValueDecl(D);
942   Record.push_back(D->getChainingSize());
943 
944   for (const auto *P : D->chain())
945     Record.AddDeclRef(P);
946   Code = serialization::DECL_INDIRECTFIELD;
947 }
948 
949 void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
950   VisitRedeclarable(D);
951   VisitDeclaratorDecl(D);
952   Record.push_back(D->getStorageClass());
953   Record.push_back(D->getTSCSpec());
954   Record.push_back(D->getInitStyle());
955   Record.push_back(D->isARCPseudoStrong());
956   if (!isa<ParmVarDecl>(D)) {
957     Record.push_back(D->isThisDeclarationADemotedDefinition());
958     Record.push_back(D->isExceptionVariable());
959     Record.push_back(D->isNRVOVariable());
960     Record.push_back(D->isCXXForRangeDecl());
961     Record.push_back(D->isObjCForDecl());
962     Record.push_back(D->isInline());
963     Record.push_back(D->isInlineSpecified());
964     Record.push_back(D->isConstexpr());
965     Record.push_back(D->isInitCapture());
966     Record.push_back(D->isPreviousDeclInSameBlockScope());
967     if (const auto *IPD = dyn_cast<ImplicitParamDecl>(D))
968       Record.push_back(static_cast<unsigned>(IPD->getParameterKind()));
969     else
970       Record.push_back(0);
971     Record.push_back(D->isEscapingByref());
972   }
973   Record.push_back(D->getLinkageInternal());
974 
975   if (D->getInit()) {
976     if (!D->isInitKnownICE())
977       Record.push_back(1);
978     else {
979       Record.push_back(
980           2 |
981           (D->isInitICE() ? 1 : 0) |
982           (D->ensureEvaluatedStmt()->HasConstantDestruction ? 4 : 0));
983     }
984     Record.AddStmt(D->getInit());
985   } else {
986     Record.push_back(0);
987   }
988 
989   if (D->hasAttr<BlocksAttr>() && D->getType()->getAsCXXRecordDecl()) {
990     ASTContext::BlockVarCopyInit Init = Writer.Context->getBlockVarCopyInit(D);
991     Record.AddStmt(Init.getCopyExpr());
992     if (Init.getCopyExpr())
993       Record.push_back(Init.canThrow());
994   }
995 
996   if (D->getStorageDuration() == SD_Static) {
997     bool ModulesCodegen = false;
998     if (Writer.WritingModule &&
999         !D->getDescribedVarTemplate() && !D->getMemberSpecializationInfo() &&
1000         !isa<VarTemplateSpecializationDecl>(D)) {
1001       // When building a C++ Modules TS module interface unit, a strong
1002       // definition in the module interface is provided by the compilation of
1003       // that module interface unit, not by its users. (Inline variables are
1004       // still emitted in module users.)
1005       ModulesCodegen =
1006           (Writer.WritingModule->Kind == Module::ModuleInterfaceUnit &&
1007            Writer.Context->GetGVALinkageForVariable(D) == GVA_StrongExternal);
1008     }
1009     Record.push_back(ModulesCodegen);
1010     if (ModulesCodegen)
1011       Writer.ModularCodegenDecls.push_back(Writer.GetDeclRef(D));
1012   }
1013 
1014   enum {
1015     VarNotTemplate = 0, VarTemplate, StaticDataMemberSpecialization
1016   };
1017   if (VarTemplateDecl *TemplD = D->getDescribedVarTemplate()) {
1018     Record.push_back(VarTemplate);
1019     Record.AddDeclRef(TemplD);
1020   } else if (MemberSpecializationInfo *SpecInfo
1021                = D->getMemberSpecializationInfo()) {
1022     Record.push_back(StaticDataMemberSpecialization);
1023     Record.AddDeclRef(SpecInfo->getInstantiatedFrom());
1024     Record.push_back(SpecInfo->getTemplateSpecializationKind());
1025     Record.AddSourceLocation(SpecInfo->getPointOfInstantiation());
1026   } else {
1027     Record.push_back(VarNotTemplate);
1028   }
1029 
1030   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1031       !D->hasAttrs() &&
1032       !D->isImplicit() &&
1033       !D->isUsed(false) &&
1034       !D->isInvalidDecl() &&
1035       !D->isReferenced() &&
1036       !D->isTopLevelDeclInObjCContainer() &&
1037       D->getAccess() == AS_none &&
1038       !D->isModulePrivate() &&
1039       !needsAnonymousDeclarationNumber(D) &&
1040       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1041       !D->hasExtInfo() &&
1042       D->getFirstDecl() == D->getMostRecentDecl() &&
1043       D->getKind() == Decl::Var &&
1044       !D->isInline() &&
1045       !D->isConstexpr() &&
1046       !D->isInitCapture() &&
1047       !D->isPreviousDeclInSameBlockScope() &&
1048       !(D->hasAttr<BlocksAttr>() && D->getType()->getAsCXXRecordDecl()) &&
1049       !D->isEscapingByref() &&
1050       D->getStorageDuration() != SD_Static &&
1051       !D->getMemberSpecializationInfo())
1052     AbbrevToUse = Writer.getDeclVarAbbrev();
1053 
1054   Code = serialization::DECL_VAR;
1055 }
1056 
1057 void ASTDeclWriter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
1058   VisitVarDecl(D);
1059   Code = serialization::DECL_IMPLICIT_PARAM;
1060 }
1061 
1062 void ASTDeclWriter::VisitParmVarDecl(ParmVarDecl *D) {
1063   VisitVarDecl(D);
1064   Record.push_back(D->isObjCMethodParameter());
1065   Record.push_back(D->getFunctionScopeDepth());
1066   Record.push_back(D->getFunctionScopeIndex());
1067   Record.push_back(D->getObjCDeclQualifier()); // FIXME: stable encoding
1068   Record.push_back(D->isKNRPromoted());
1069   Record.push_back(D->hasInheritedDefaultArg());
1070   Record.push_back(D->hasUninstantiatedDefaultArg());
1071   if (D->hasUninstantiatedDefaultArg())
1072     Record.AddStmt(D->getUninstantiatedDefaultArg());
1073   Code = serialization::DECL_PARM_VAR;
1074 
1075   assert(!D->isARCPseudoStrong()); // can be true of ImplicitParamDecl
1076 
1077   // If the assumptions about the DECL_PARM_VAR abbrev are true, use it.  Here
1078   // we dynamically check for the properties that we optimize for, but don't
1079   // know are true of all PARM_VAR_DECLs.
1080   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1081       !D->hasAttrs() &&
1082       !D->hasExtInfo() &&
1083       !D->isImplicit() &&
1084       !D->isUsed(false) &&
1085       !D->isInvalidDecl() &&
1086       !D->isReferenced() &&
1087       D->getAccess() == AS_none &&
1088       !D->isModulePrivate() &&
1089       D->getStorageClass() == 0 &&
1090       D->getInitStyle() == VarDecl::CInit && // Can params have anything else?
1091       D->getFunctionScopeDepth() == 0 &&
1092       D->getObjCDeclQualifier() == 0 &&
1093       !D->isKNRPromoted() &&
1094       !D->hasInheritedDefaultArg() &&
1095       D->getInit() == nullptr &&
1096       !D->hasUninstantiatedDefaultArg())  // No default expr.
1097     AbbrevToUse = Writer.getDeclParmVarAbbrev();
1098 
1099   // Check things we know are true of *every* PARM_VAR_DECL, which is more than
1100   // just us assuming it.
1101   assert(!D->getTSCSpec() && "PARM_VAR_DECL can't use TLS");
1102   assert(!D->isThisDeclarationADemotedDefinition()
1103          && "PARM_VAR_DECL can't be demoted definition.");
1104   assert(D->getAccess() == AS_none && "PARM_VAR_DECL can't be public/private");
1105   assert(!D->isExceptionVariable() && "PARM_VAR_DECL can't be exception var");
1106   assert(D->getPreviousDecl() == nullptr && "PARM_VAR_DECL can't be redecl");
1107   assert(!D->isStaticDataMember() &&
1108          "PARM_VAR_DECL can't be static data member");
1109 }
1110 
1111 void ASTDeclWriter::VisitDecompositionDecl(DecompositionDecl *D) {
1112   // Record the number of bindings first to simplify deserialization.
1113   Record.push_back(D->bindings().size());
1114 
1115   VisitVarDecl(D);
1116   for (auto *B : D->bindings())
1117     Record.AddDeclRef(B);
1118   Code = serialization::DECL_DECOMPOSITION;
1119 }
1120 
1121 void ASTDeclWriter::VisitBindingDecl(BindingDecl *D) {
1122   VisitValueDecl(D);
1123   Record.AddStmt(D->getBinding());
1124   Code = serialization::DECL_BINDING;
1125 }
1126 
1127 void ASTDeclWriter::VisitFileScopeAsmDecl(FileScopeAsmDecl *D) {
1128   VisitDecl(D);
1129   Record.AddStmt(D->getAsmString());
1130   Record.AddSourceLocation(D->getRParenLoc());
1131   Code = serialization::DECL_FILE_SCOPE_ASM;
1132 }
1133 
1134 void ASTDeclWriter::VisitEmptyDecl(EmptyDecl *D) {
1135   VisitDecl(D);
1136   Code = serialization::DECL_EMPTY;
1137 }
1138 
1139 void ASTDeclWriter::VisitLifetimeExtendedTemporaryDecl(
1140     LifetimeExtendedTemporaryDecl *D) {
1141   VisitDecl(D);
1142   Record.AddDeclRef(D->getExtendingDecl());
1143   Record.AddStmt(D->getTemporaryExpr());
1144   Record.push_back(static_cast<bool>(D->getValue()));
1145   if (D->getValue())
1146     Record.AddAPValue(*D->getValue());
1147   Record.push_back(D->getManglingNumber());
1148   Code = serialization::DECL_LIFETIME_EXTENDED_TEMPORARY;
1149 }
1150 void ASTDeclWriter::VisitBlockDecl(BlockDecl *D) {
1151   VisitDecl(D);
1152   Record.AddStmt(D->getBody());
1153   Record.AddTypeSourceInfo(D->getSignatureAsWritten());
1154   Record.push_back(D->param_size());
1155   for (ParmVarDecl *P : D->parameters())
1156     Record.AddDeclRef(P);
1157   Record.push_back(D->isVariadic());
1158   Record.push_back(D->blockMissingReturnType());
1159   Record.push_back(D->isConversionFromLambda());
1160   Record.push_back(D->doesNotEscape());
1161   Record.push_back(D->canAvoidCopyToHeap());
1162   Record.push_back(D->capturesCXXThis());
1163   Record.push_back(D->getNumCaptures());
1164   for (const auto &capture : D->captures()) {
1165     Record.AddDeclRef(capture.getVariable());
1166 
1167     unsigned flags = 0;
1168     if (capture.isByRef()) flags |= 1;
1169     if (capture.isNested()) flags |= 2;
1170     if (capture.hasCopyExpr()) flags |= 4;
1171     Record.push_back(flags);
1172 
1173     if (capture.hasCopyExpr()) Record.AddStmt(capture.getCopyExpr());
1174   }
1175 
1176   Code = serialization::DECL_BLOCK;
1177 }
1178 
1179 void ASTDeclWriter::VisitCapturedDecl(CapturedDecl *CD) {
1180   Record.push_back(CD->getNumParams());
1181   VisitDecl(CD);
1182   Record.push_back(CD->getContextParamPosition());
1183   Record.push_back(CD->isNothrow() ? 1 : 0);
1184   // Body is stored by VisitCapturedStmt.
1185   for (unsigned I = 0; I < CD->getNumParams(); ++I)
1186     Record.AddDeclRef(CD->getParam(I));
1187   Code = serialization::DECL_CAPTURED;
1188 }
1189 
1190 void ASTDeclWriter::VisitLinkageSpecDecl(LinkageSpecDecl *D) {
1191   VisitDecl(D);
1192   Record.push_back(D->getLanguage());
1193   Record.AddSourceLocation(D->getExternLoc());
1194   Record.AddSourceLocation(D->getRBraceLoc());
1195   Code = serialization::DECL_LINKAGE_SPEC;
1196 }
1197 
1198 void ASTDeclWriter::VisitExportDecl(ExportDecl *D) {
1199   VisitDecl(D);
1200   Record.AddSourceLocation(D->getRBraceLoc());
1201   Code = serialization::DECL_EXPORT;
1202 }
1203 
1204 void ASTDeclWriter::VisitLabelDecl(LabelDecl *D) {
1205   VisitNamedDecl(D);
1206   Record.AddSourceLocation(D->getBeginLoc());
1207   Code = serialization::DECL_LABEL;
1208 }
1209 
1210 
1211 void ASTDeclWriter::VisitNamespaceDecl(NamespaceDecl *D) {
1212   VisitRedeclarable(D);
1213   VisitNamedDecl(D);
1214   Record.push_back(D->isInline());
1215   Record.AddSourceLocation(D->getBeginLoc());
1216   Record.AddSourceLocation(D->getRBraceLoc());
1217 
1218   if (D->isOriginalNamespace())
1219     Record.AddDeclRef(D->getAnonymousNamespace());
1220   Code = serialization::DECL_NAMESPACE;
1221 
1222   if (Writer.hasChain() && D->isAnonymousNamespace() &&
1223       D == D->getMostRecentDecl()) {
1224     // This is a most recent reopening of the anonymous namespace. If its parent
1225     // is in a previous PCH (or is the TU), mark that parent for update, because
1226     // the original namespace always points to the latest re-opening of its
1227     // anonymous namespace.
1228     Decl *Parent = cast<Decl>(
1229         D->getParent()->getRedeclContext()->getPrimaryContext());
1230     if (Parent->isFromASTFile() || isa<TranslationUnitDecl>(Parent)) {
1231       Writer.DeclUpdates[Parent].push_back(
1232           ASTWriter::DeclUpdate(UPD_CXX_ADDED_ANONYMOUS_NAMESPACE, D));
1233     }
1234   }
1235 }
1236 
1237 void ASTDeclWriter::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
1238   VisitRedeclarable(D);
1239   VisitNamedDecl(D);
1240   Record.AddSourceLocation(D->getNamespaceLoc());
1241   Record.AddSourceLocation(D->getTargetNameLoc());
1242   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1243   Record.AddDeclRef(D->getNamespace());
1244   Code = serialization::DECL_NAMESPACE_ALIAS;
1245 }
1246 
1247 void ASTDeclWriter::VisitUsingDecl(UsingDecl *D) {
1248   VisitNamedDecl(D);
1249   Record.AddSourceLocation(D->getUsingLoc());
1250   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1251   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
1252   Record.AddDeclRef(D->FirstUsingShadow.getPointer());
1253   Record.push_back(D->hasTypename());
1254   Record.AddDeclRef(Context.getInstantiatedFromUsingDecl(D));
1255   Code = serialization::DECL_USING;
1256 }
1257 
1258 void ASTDeclWriter::VisitUsingPackDecl(UsingPackDecl *D) {
1259   Record.push_back(D->NumExpansions);
1260   VisitNamedDecl(D);
1261   Record.AddDeclRef(D->getInstantiatedFromUsingDecl());
1262   for (auto *E : D->expansions())
1263     Record.AddDeclRef(E);
1264   Code = serialization::DECL_USING_PACK;
1265 }
1266 
1267 void ASTDeclWriter::VisitUsingShadowDecl(UsingShadowDecl *D) {
1268   VisitRedeclarable(D);
1269   VisitNamedDecl(D);
1270   Record.AddDeclRef(D->getTargetDecl());
1271   Record.push_back(D->getIdentifierNamespace());
1272   Record.AddDeclRef(D->UsingOrNextShadow);
1273   Record.AddDeclRef(Context.getInstantiatedFromUsingShadowDecl(D));
1274   Code = serialization::DECL_USING_SHADOW;
1275 }
1276 
1277 void ASTDeclWriter::VisitConstructorUsingShadowDecl(
1278     ConstructorUsingShadowDecl *D) {
1279   VisitUsingShadowDecl(D);
1280   Record.AddDeclRef(D->NominatedBaseClassShadowDecl);
1281   Record.AddDeclRef(D->ConstructedBaseClassShadowDecl);
1282   Record.push_back(D->IsVirtual);
1283   Code = serialization::DECL_CONSTRUCTOR_USING_SHADOW;
1284 }
1285 
1286 void ASTDeclWriter::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1287   VisitNamedDecl(D);
1288   Record.AddSourceLocation(D->getUsingLoc());
1289   Record.AddSourceLocation(D->getNamespaceKeyLocation());
1290   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1291   Record.AddDeclRef(D->getNominatedNamespace());
1292   Record.AddDeclRef(dyn_cast<Decl>(D->getCommonAncestor()));
1293   Code = serialization::DECL_USING_DIRECTIVE;
1294 }
1295 
1296 void ASTDeclWriter::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1297   VisitValueDecl(D);
1298   Record.AddSourceLocation(D->getUsingLoc());
1299   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1300   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
1301   Record.AddSourceLocation(D->getEllipsisLoc());
1302   Code = serialization::DECL_UNRESOLVED_USING_VALUE;
1303 }
1304 
1305 void ASTDeclWriter::VisitUnresolvedUsingTypenameDecl(
1306                                                UnresolvedUsingTypenameDecl *D) {
1307   VisitTypeDecl(D);
1308   Record.AddSourceLocation(D->getTypenameLoc());
1309   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1310   Record.AddSourceLocation(D->getEllipsisLoc());
1311   Code = serialization::DECL_UNRESOLVED_USING_TYPENAME;
1312 }
1313 
1314 void ASTDeclWriter::VisitCXXRecordDecl(CXXRecordDecl *D) {
1315   VisitRecordDecl(D);
1316 
1317   enum {
1318     CXXRecNotTemplate = 0, CXXRecTemplate, CXXRecMemberSpecialization
1319   };
1320   if (ClassTemplateDecl *TemplD = D->getDescribedClassTemplate()) {
1321     Record.push_back(CXXRecTemplate);
1322     Record.AddDeclRef(TemplD);
1323   } else if (MemberSpecializationInfo *MSInfo
1324                = D->getMemberSpecializationInfo()) {
1325     Record.push_back(CXXRecMemberSpecialization);
1326     Record.AddDeclRef(MSInfo->getInstantiatedFrom());
1327     Record.push_back(MSInfo->getTemplateSpecializationKind());
1328     Record.AddSourceLocation(MSInfo->getPointOfInstantiation());
1329   } else {
1330     Record.push_back(CXXRecNotTemplate);
1331   }
1332 
1333   Record.push_back(D->isThisDeclarationADefinition());
1334   if (D->isThisDeclarationADefinition())
1335     Record.AddCXXDefinitionData(D);
1336 
1337   // Store (what we currently believe to be) the key function to avoid
1338   // deserializing every method so we can compute it.
1339   if (D->isCompleteDefinition())
1340     Record.AddDeclRef(Context.getCurrentKeyFunction(D));
1341 
1342   Code = serialization::DECL_CXX_RECORD;
1343 }
1344 
1345 void ASTDeclWriter::VisitCXXMethodDecl(CXXMethodDecl *D) {
1346   VisitFunctionDecl(D);
1347   if (D->isCanonicalDecl()) {
1348     Record.push_back(D->size_overridden_methods());
1349     for (const CXXMethodDecl *MD : D->overridden_methods())
1350       Record.AddDeclRef(MD);
1351   } else {
1352     // We only need to record overridden methods once for the canonical decl.
1353     Record.push_back(0);
1354   }
1355 
1356   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1357       D->getFirstDecl() == D->getMostRecentDecl() &&
1358       !D->isInvalidDecl() &&
1359       !D->hasAttrs() &&
1360       !D->isTopLevelDeclInObjCContainer() &&
1361       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1362       !D->hasExtInfo() &&
1363       !D->hasInheritedPrototype() &&
1364       D->hasWrittenPrototype())
1365     AbbrevToUse = Writer.getDeclCXXMethodAbbrev();
1366 
1367   Code = serialization::DECL_CXX_METHOD;
1368 }
1369 
1370 void ASTDeclWriter::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1371   Record.push_back(D->getTraillingAllocKind());
1372   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
1373   if (auto Inherited = D->getInheritedConstructor()) {
1374     Record.AddDeclRef(Inherited.getShadowDecl());
1375     Record.AddDeclRef(Inherited.getConstructor());
1376   }
1377 
1378   VisitCXXMethodDecl(D);
1379   Code = serialization::DECL_CXX_CONSTRUCTOR;
1380 }
1381 
1382 void ASTDeclWriter::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1383   VisitCXXMethodDecl(D);
1384 
1385   Record.AddDeclRef(D->getOperatorDelete());
1386   if (D->getOperatorDelete())
1387     Record.AddStmt(D->getOperatorDeleteThisArg());
1388 
1389   Code = serialization::DECL_CXX_DESTRUCTOR;
1390 }
1391 
1392 void ASTDeclWriter::VisitCXXConversionDecl(CXXConversionDecl *D) {
1393   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
1394   VisitCXXMethodDecl(D);
1395   Code = serialization::DECL_CXX_CONVERSION;
1396 }
1397 
1398 void ASTDeclWriter::VisitImportDecl(ImportDecl *D) {
1399   VisitDecl(D);
1400   Record.push_back(Writer.getSubmoduleID(D->getImportedModule()));
1401   ArrayRef<SourceLocation> IdentifierLocs = D->getIdentifierLocs();
1402   Record.push_back(!IdentifierLocs.empty());
1403   if (IdentifierLocs.empty()) {
1404     Record.AddSourceLocation(D->getEndLoc());
1405     Record.push_back(1);
1406   } else {
1407     for (unsigned I = 0, N = IdentifierLocs.size(); I != N; ++I)
1408       Record.AddSourceLocation(IdentifierLocs[I]);
1409     Record.push_back(IdentifierLocs.size());
1410   }
1411   // Note: the number of source locations must always be the last element in
1412   // the record.
1413   Code = serialization::DECL_IMPORT;
1414 }
1415 
1416 void ASTDeclWriter::VisitAccessSpecDecl(AccessSpecDecl *D) {
1417   VisitDecl(D);
1418   Record.AddSourceLocation(D->getColonLoc());
1419   Code = serialization::DECL_ACCESS_SPEC;
1420 }
1421 
1422 void ASTDeclWriter::VisitFriendDecl(FriendDecl *D) {
1423   // Record the number of friend type template parameter lists here
1424   // so as to simplify memory allocation during deserialization.
1425   Record.push_back(D->NumTPLists);
1426   VisitDecl(D);
1427   bool hasFriendDecl = D->Friend.is<NamedDecl*>();
1428   Record.push_back(hasFriendDecl);
1429   if (hasFriendDecl)
1430     Record.AddDeclRef(D->getFriendDecl());
1431   else
1432     Record.AddTypeSourceInfo(D->getFriendType());
1433   for (unsigned i = 0; i < D->NumTPLists; ++i)
1434     Record.AddTemplateParameterList(D->getFriendTypeTemplateParameterList(i));
1435   Record.AddDeclRef(D->getNextFriend());
1436   Record.push_back(D->UnsupportedFriend);
1437   Record.AddSourceLocation(D->FriendLoc);
1438   Code = serialization::DECL_FRIEND;
1439 }
1440 
1441 void ASTDeclWriter::VisitFriendTemplateDecl(FriendTemplateDecl *D) {
1442   VisitDecl(D);
1443   Record.push_back(D->getNumTemplateParameters());
1444   for (unsigned i = 0, e = D->getNumTemplateParameters(); i != e; ++i)
1445     Record.AddTemplateParameterList(D->getTemplateParameterList(i));
1446   Record.push_back(D->getFriendDecl() != nullptr);
1447   if (D->getFriendDecl())
1448     Record.AddDeclRef(D->getFriendDecl());
1449   else
1450     Record.AddTypeSourceInfo(D->getFriendType());
1451   Record.AddSourceLocation(D->getFriendLoc());
1452   Code = serialization::DECL_FRIEND_TEMPLATE;
1453 }
1454 
1455 void ASTDeclWriter::VisitTemplateDecl(TemplateDecl *D) {
1456   VisitNamedDecl(D);
1457 
1458   Record.AddDeclRef(D->getTemplatedDecl());
1459   Record.AddTemplateParameterList(D->getTemplateParameters());
1460 }
1461 
1462 void ASTDeclWriter::VisitConceptDecl(ConceptDecl *D) {
1463   VisitTemplateDecl(D);
1464   Record.AddStmt(D->getConstraintExpr());
1465   Code = serialization::DECL_CONCEPT;
1466 }
1467 
1468 void ASTDeclWriter::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
1469   VisitRedeclarable(D);
1470 
1471   // Emit data to initialize CommonOrPrev before VisitTemplateDecl so that
1472   // getCommonPtr() can be used while this is still initializing.
1473   if (D->isFirstDecl()) {
1474     // This declaration owns the 'common' pointer, so serialize that data now.
1475     Record.AddDeclRef(D->getInstantiatedFromMemberTemplate());
1476     if (D->getInstantiatedFromMemberTemplate())
1477       Record.push_back(D->isMemberSpecialization());
1478   }
1479 
1480   VisitTemplateDecl(D);
1481   Record.push_back(D->getIdentifierNamespace());
1482 }
1483 
1484 void ASTDeclWriter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
1485   VisitRedeclarableTemplateDecl(D);
1486 
1487   if (D->isFirstDecl())
1488     AddTemplateSpecializations(D);
1489   Code = serialization::DECL_CLASS_TEMPLATE;
1490 }
1491 
1492 void ASTDeclWriter::VisitClassTemplateSpecializationDecl(
1493                                            ClassTemplateSpecializationDecl *D) {
1494   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1495 
1496   VisitCXXRecordDecl(D);
1497 
1498   llvm::PointerUnion<ClassTemplateDecl *,
1499                      ClassTemplatePartialSpecializationDecl *> InstFrom
1500     = D->getSpecializedTemplateOrPartial();
1501   if (Decl *InstFromD = InstFrom.dyn_cast<ClassTemplateDecl *>()) {
1502     Record.AddDeclRef(InstFromD);
1503   } else {
1504     Record.AddDeclRef(InstFrom.get<ClassTemplatePartialSpecializationDecl *>());
1505     Record.AddTemplateArgumentList(&D->getTemplateInstantiationArgs());
1506   }
1507 
1508   Record.AddTemplateArgumentList(&D->getTemplateArgs());
1509   Record.AddSourceLocation(D->getPointOfInstantiation());
1510   Record.push_back(D->getSpecializationKind());
1511   Record.push_back(D->isCanonicalDecl());
1512 
1513   if (D->isCanonicalDecl()) {
1514     // When reading, we'll add it to the folding set of the following template.
1515     Record.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl());
1516   }
1517 
1518   // Explicit info.
1519   Record.AddTypeSourceInfo(D->getTypeAsWritten());
1520   if (D->getTypeAsWritten()) {
1521     Record.AddSourceLocation(D->getExternLoc());
1522     Record.AddSourceLocation(D->getTemplateKeywordLoc());
1523   }
1524 
1525   Code = serialization::DECL_CLASS_TEMPLATE_SPECIALIZATION;
1526 }
1527 
1528 void ASTDeclWriter::VisitClassTemplatePartialSpecializationDecl(
1529                                     ClassTemplatePartialSpecializationDecl *D) {
1530   VisitClassTemplateSpecializationDecl(D);
1531 
1532   Record.AddTemplateParameterList(D->getTemplateParameters());
1533   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1534 
1535   // These are read/set from/to the first declaration.
1536   if (D->getPreviousDecl() == nullptr) {
1537     Record.AddDeclRef(D->getInstantiatedFromMember());
1538     Record.push_back(D->isMemberSpecialization());
1539   }
1540 
1541   Code = serialization::DECL_CLASS_TEMPLATE_PARTIAL_SPECIALIZATION;
1542 }
1543 
1544 void ASTDeclWriter::VisitVarTemplateDecl(VarTemplateDecl *D) {
1545   VisitRedeclarableTemplateDecl(D);
1546 
1547   if (D->isFirstDecl())
1548     AddTemplateSpecializations(D);
1549   Code = serialization::DECL_VAR_TEMPLATE;
1550 }
1551 
1552 void ASTDeclWriter::VisitVarTemplateSpecializationDecl(
1553     VarTemplateSpecializationDecl *D) {
1554   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1555 
1556   VisitVarDecl(D);
1557 
1558   llvm::PointerUnion<VarTemplateDecl *, VarTemplatePartialSpecializationDecl *>
1559   InstFrom = D->getSpecializedTemplateOrPartial();
1560   if (Decl *InstFromD = InstFrom.dyn_cast<VarTemplateDecl *>()) {
1561     Record.AddDeclRef(InstFromD);
1562   } else {
1563     Record.AddDeclRef(InstFrom.get<VarTemplatePartialSpecializationDecl *>());
1564     Record.AddTemplateArgumentList(&D->getTemplateInstantiationArgs());
1565   }
1566 
1567   // Explicit info.
1568   Record.AddTypeSourceInfo(D->getTypeAsWritten());
1569   if (D->getTypeAsWritten()) {
1570     Record.AddSourceLocation(D->getExternLoc());
1571     Record.AddSourceLocation(D->getTemplateKeywordLoc());
1572   }
1573 
1574   Record.AddTemplateArgumentList(&D->getTemplateArgs());
1575   Record.AddSourceLocation(D->getPointOfInstantiation());
1576   Record.push_back(D->getSpecializationKind());
1577   Record.push_back(D->IsCompleteDefinition);
1578   Record.push_back(D->isCanonicalDecl());
1579 
1580   if (D->isCanonicalDecl()) {
1581     // When reading, we'll add it to the folding set of the following template.
1582     Record.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl());
1583   }
1584 
1585   Code = serialization::DECL_VAR_TEMPLATE_SPECIALIZATION;
1586 }
1587 
1588 void ASTDeclWriter::VisitVarTemplatePartialSpecializationDecl(
1589     VarTemplatePartialSpecializationDecl *D) {
1590   VisitVarTemplateSpecializationDecl(D);
1591 
1592   Record.AddTemplateParameterList(D->getTemplateParameters());
1593   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1594 
1595   // These are read/set from/to the first declaration.
1596   if (D->getPreviousDecl() == nullptr) {
1597     Record.AddDeclRef(D->getInstantiatedFromMember());
1598     Record.push_back(D->isMemberSpecialization());
1599   }
1600 
1601   Code = serialization::DECL_VAR_TEMPLATE_PARTIAL_SPECIALIZATION;
1602 }
1603 
1604 void ASTDeclWriter::VisitClassScopeFunctionSpecializationDecl(
1605                                     ClassScopeFunctionSpecializationDecl *D) {
1606   VisitDecl(D);
1607   Record.AddDeclRef(D->getSpecialization());
1608   Record.push_back(D->hasExplicitTemplateArgs());
1609   if (D->hasExplicitTemplateArgs())
1610     Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1611   Code = serialization::DECL_CLASS_SCOPE_FUNCTION_SPECIALIZATION;
1612 }
1613 
1614 
1615 void ASTDeclWriter::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
1616   VisitRedeclarableTemplateDecl(D);
1617 
1618   if (D->isFirstDecl())
1619     AddTemplateSpecializations(D);
1620   Code = serialization::DECL_FUNCTION_TEMPLATE;
1621 }
1622 
1623 void ASTDeclWriter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
1624   VisitTypeDecl(D);
1625 
1626   Record.push_back(D->wasDeclaredWithTypename());
1627   // TODO: Concepts - constrained parameters.
1628   bool OwnsDefaultArg = D->hasDefaultArgument() &&
1629                         !D->defaultArgumentWasInherited();
1630   Record.push_back(OwnsDefaultArg);
1631   if (OwnsDefaultArg)
1632     Record.AddTypeSourceInfo(D->getDefaultArgumentInfo());
1633 
1634   Code = serialization::DECL_TEMPLATE_TYPE_PARM;
1635 }
1636 
1637 void ASTDeclWriter::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
1638   // For an expanded parameter pack, record the number of expansion types here
1639   // so that it's easier for deserialization to allocate the right amount of
1640   // memory.
1641   if (D->isExpandedParameterPack())
1642     Record.push_back(D->getNumExpansionTypes());
1643 
1644   VisitDeclaratorDecl(D);
1645   // TemplateParmPosition.
1646   Record.push_back(D->getDepth());
1647   Record.push_back(D->getPosition());
1648 
1649   if (D->isExpandedParameterPack()) {
1650     for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1651       Record.AddTypeRef(D->getExpansionType(I));
1652       Record.AddTypeSourceInfo(D->getExpansionTypeSourceInfo(I));
1653     }
1654 
1655     Code = serialization::DECL_EXPANDED_NON_TYPE_TEMPLATE_PARM_PACK;
1656   } else {
1657     // TODO: Concepts - constrained parameters.
1658     // Rest of NonTypeTemplateParmDecl.
1659     Record.push_back(D->isParameterPack());
1660     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1661                           !D->defaultArgumentWasInherited();
1662     Record.push_back(OwnsDefaultArg);
1663     if (OwnsDefaultArg)
1664       Record.AddStmt(D->getDefaultArgument());
1665     Code = serialization::DECL_NON_TYPE_TEMPLATE_PARM;
1666   }
1667 }
1668 
1669 void ASTDeclWriter::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
1670   // For an expanded parameter pack, record the number of expansion types here
1671   // so that it's easier for deserialization to allocate the right amount of
1672   // memory.
1673   if (D->isExpandedParameterPack())
1674     Record.push_back(D->getNumExpansionTemplateParameters());
1675 
1676   VisitTemplateDecl(D);
1677   // TemplateParmPosition.
1678   Record.push_back(D->getDepth());
1679   Record.push_back(D->getPosition());
1680 
1681   if (D->isExpandedParameterPack()) {
1682     for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
1683          I != N; ++I)
1684       Record.AddTemplateParameterList(D->getExpansionTemplateParameters(I));
1685     Code = serialization::DECL_EXPANDED_TEMPLATE_TEMPLATE_PARM_PACK;
1686   } else {
1687     // TODO: Concepts - constrained parameters.
1688     // Rest of TemplateTemplateParmDecl.
1689     Record.push_back(D->isParameterPack());
1690     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1691                           !D->defaultArgumentWasInherited();
1692     Record.push_back(OwnsDefaultArg);
1693     if (OwnsDefaultArg)
1694       Record.AddTemplateArgumentLoc(D->getDefaultArgument());
1695     Code = serialization::DECL_TEMPLATE_TEMPLATE_PARM;
1696   }
1697 }
1698 
1699 void ASTDeclWriter::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
1700   VisitRedeclarableTemplateDecl(D);
1701   Code = serialization::DECL_TYPE_ALIAS_TEMPLATE;
1702 }
1703 
1704 void ASTDeclWriter::VisitStaticAssertDecl(StaticAssertDecl *D) {
1705   VisitDecl(D);
1706   Record.AddStmt(D->getAssertExpr());
1707   Record.push_back(D->isFailed());
1708   Record.AddStmt(D->getMessage());
1709   Record.AddSourceLocation(D->getRParenLoc());
1710   Code = serialization::DECL_STATIC_ASSERT;
1711 }
1712 
1713 /// Emit the DeclContext part of a declaration context decl.
1714 void ASTDeclWriter::VisitDeclContext(DeclContext *DC) {
1715   Record.AddOffset(Writer.WriteDeclContextLexicalBlock(Context, DC));
1716   Record.AddOffset(Writer.WriteDeclContextVisibleBlock(Context, DC));
1717 }
1718 
1719 const Decl *ASTWriter::getFirstLocalDecl(const Decl *D) {
1720   assert(IsLocalDecl(D) && "expected a local declaration");
1721 
1722   const Decl *Canon = D->getCanonicalDecl();
1723   if (IsLocalDecl(Canon))
1724     return Canon;
1725 
1726   const Decl *&CacheEntry = FirstLocalDeclCache[Canon];
1727   if (CacheEntry)
1728     return CacheEntry;
1729 
1730   for (const Decl *Redecl = D; Redecl; Redecl = Redecl->getPreviousDecl())
1731     if (IsLocalDecl(Redecl))
1732       D = Redecl;
1733   return CacheEntry = D;
1734 }
1735 
1736 template <typename T>
1737 void ASTDeclWriter::VisitRedeclarable(Redeclarable<T> *D) {
1738   T *First = D->getFirstDecl();
1739   T *MostRecent = First->getMostRecentDecl();
1740   T *DAsT = static_cast<T *>(D);
1741   if (MostRecent != First) {
1742     assert(isRedeclarableDeclKind(DAsT->getKind()) &&
1743            "Not considered redeclarable?");
1744 
1745     Record.AddDeclRef(First);
1746 
1747     // Write out a list of local redeclarations of this declaration if it's the
1748     // first local declaration in the chain.
1749     const Decl *FirstLocal = Writer.getFirstLocalDecl(DAsT);
1750     if (DAsT == FirstLocal) {
1751       // Emit a list of all imported first declarations so that we can be sure
1752       // that all redeclarations visible to this module are before D in the
1753       // redecl chain.
1754       unsigned I = Record.size();
1755       Record.push_back(0);
1756       if (Writer.Chain)
1757         AddFirstDeclFromEachModule(DAsT, /*IncludeLocal*/false);
1758       // This is the number of imported first declarations + 1.
1759       Record[I] = Record.size() - I;
1760 
1761       // Collect the set of local redeclarations of this declaration, from
1762       // newest to oldest.
1763       ASTWriter::RecordData LocalRedecls;
1764       ASTRecordWriter LocalRedeclWriter(Record, LocalRedecls);
1765       for (const Decl *Prev = FirstLocal->getMostRecentDecl();
1766            Prev != FirstLocal; Prev = Prev->getPreviousDecl())
1767         if (!Prev->isFromASTFile())
1768           LocalRedeclWriter.AddDeclRef(Prev);
1769 
1770       // If we have any redecls, write them now as a separate record preceding
1771       // the declaration itself.
1772       if (LocalRedecls.empty())
1773         Record.push_back(0);
1774       else
1775         Record.AddOffset(LocalRedeclWriter.Emit(LOCAL_REDECLARATIONS));
1776     } else {
1777       Record.push_back(0);
1778       Record.AddDeclRef(FirstLocal);
1779     }
1780 
1781     // Make sure that we serialize both the previous and the most-recent
1782     // declarations, which (transitively) ensures that all declarations in the
1783     // chain get serialized.
1784     //
1785     // FIXME: This is not correct; when we reach an imported declaration we
1786     // won't emit its previous declaration.
1787     (void)Writer.GetDeclRef(D->getPreviousDecl());
1788     (void)Writer.GetDeclRef(MostRecent);
1789   } else {
1790     // We use the sentinel value 0 to indicate an only declaration.
1791     Record.push_back(0);
1792   }
1793 }
1794 
1795 void ASTDeclWriter::VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D) {
1796   Record.push_back(D->varlist_size());
1797   VisitDecl(D);
1798   for (auto *I : D->varlists())
1799     Record.AddStmt(I);
1800   Code = serialization::DECL_OMP_THREADPRIVATE;
1801 }
1802 
1803 void ASTDeclWriter::VisitOMPAllocateDecl(OMPAllocateDecl *D) {
1804   Record.push_back(D->varlist_size());
1805   Record.push_back(D->clauselist_size());
1806   VisitDecl(D);
1807   for (auto *I : D->varlists())
1808     Record.AddStmt(I);
1809   OMPClauseWriter ClauseWriter(Record);
1810   for (OMPClause *C : D->clauselists())
1811     ClauseWriter.writeClause(C);
1812   Code = serialization::DECL_OMP_ALLOCATE;
1813 }
1814 
1815 void ASTDeclWriter::VisitOMPRequiresDecl(OMPRequiresDecl *D) {
1816   Record.push_back(D->clauselist_size());
1817   VisitDecl(D);
1818   OMPClauseWriter ClauseWriter(Record);
1819   for (OMPClause *C : D->clauselists())
1820     ClauseWriter.writeClause(C);
1821   Code = serialization::DECL_OMP_REQUIRES;
1822 }
1823 
1824 void ASTDeclWriter::VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D) {
1825   VisitValueDecl(D);
1826   Record.AddSourceLocation(D->getBeginLoc());
1827   Record.AddStmt(D->getCombinerIn());
1828   Record.AddStmt(D->getCombinerOut());
1829   Record.AddStmt(D->getCombiner());
1830   Record.AddStmt(D->getInitOrig());
1831   Record.AddStmt(D->getInitPriv());
1832   Record.AddStmt(D->getInitializer());
1833   Record.push_back(D->getInitializerKind());
1834   Record.AddDeclRef(D->getPrevDeclInScope());
1835   Code = serialization::DECL_OMP_DECLARE_REDUCTION;
1836 }
1837 
1838 void ASTDeclWriter::VisitOMPDeclareMapperDecl(OMPDeclareMapperDecl *D) {
1839   Record.push_back(D->clauselist_size());
1840   VisitValueDecl(D);
1841   Record.AddSourceLocation(D->getBeginLoc());
1842   Record.AddStmt(D->getMapperVarRef());
1843   Record.AddDeclarationName(D->getVarName());
1844   Record.AddDeclRef(D->getPrevDeclInScope());
1845   OMPClauseWriter ClauseWriter(Record);
1846   for (OMPClause *C : D->clauselists())
1847     ClauseWriter.writeClause(C);
1848   Code = serialization::DECL_OMP_DECLARE_MAPPER;
1849 }
1850 
1851 void ASTDeclWriter::VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D) {
1852   VisitVarDecl(D);
1853   Code = serialization::DECL_OMP_CAPTUREDEXPR;
1854 }
1855 
1856 //===----------------------------------------------------------------------===//
1857 // ASTWriter Implementation
1858 //===----------------------------------------------------------------------===//
1859 
1860 void ASTWriter::WriteDeclAbbrevs() {
1861   using namespace llvm;
1862 
1863   std::shared_ptr<BitCodeAbbrev> Abv;
1864 
1865   // Abbreviation for DECL_FIELD
1866   Abv = std::make_shared<BitCodeAbbrev>();
1867   Abv->Add(BitCodeAbbrevOp(serialization::DECL_FIELD));
1868   // Decl
1869   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1870   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1871   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1872   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1873   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1874   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1875   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1876   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1877   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1878   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1879   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1880   // NamedDecl
1881   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1882   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1883   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1884   // ValueDecl
1885   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1886   // DeclaratorDecl
1887   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1888   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1889   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
1890   // FieldDecl
1891   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1892   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
1893   // Type Source Info
1894   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1895   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1896   DeclFieldAbbrev = Stream.EmitAbbrev(std::move(Abv));
1897 
1898   // Abbreviation for DECL_OBJC_IVAR
1899   Abv = std::make_shared<BitCodeAbbrev>();
1900   Abv->Add(BitCodeAbbrevOp(serialization::DECL_OBJC_IVAR));
1901   // Decl
1902   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1903   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1904   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1905   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1906   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1907   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1908   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1909   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1910   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1911   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1912   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1913   // NamedDecl
1914   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1915   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1916   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1917   // ValueDecl
1918   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1919   // DeclaratorDecl
1920   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1921   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1922   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
1923   // FieldDecl
1924   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1925   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
1926   // ObjC Ivar
1927   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getAccessControl
1928   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getSynthesize
1929   // Type Source Info
1930   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1931   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1932   DeclObjCIvarAbbrev = Stream.EmitAbbrev(std::move(Abv));
1933 
1934   // Abbreviation for DECL_ENUM
1935   Abv = std::make_shared<BitCodeAbbrev>();
1936   Abv->Add(BitCodeAbbrevOp(serialization::DECL_ENUM));
1937   // Redeclarable
1938   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1939   // Decl
1940   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1941   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1942   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1943   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1944   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1945   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1946   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1947   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1948   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1949   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1950   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1951   // NamedDecl
1952   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1953   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1954   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1955   // TypeDecl
1956   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1957   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1958   // TagDecl
1959   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
1960   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
1961   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
1962   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
1963   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
1964   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
1965   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1966   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1967   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
1968   // EnumDecl
1969   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddTypeRef
1970   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IntegerType
1971   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getPromotionType
1972   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumPositiveBits
1973   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumNegativeBits
1974   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScoped
1975   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScopedUsingClassTag
1976   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isFixed
1977   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));// ODRHash
1978   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InstantiatedMembEnum
1979   // DC
1980   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
1981   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
1982   DeclEnumAbbrev = Stream.EmitAbbrev(std::move(Abv));
1983 
1984   // Abbreviation for DECL_RECORD
1985   Abv = std::make_shared<BitCodeAbbrev>();
1986   Abv->Add(BitCodeAbbrevOp(serialization::DECL_RECORD));
1987   // Redeclarable
1988   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1989   // Decl
1990   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1991   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1992   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1993   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1994   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1995   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1996   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1997   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1998   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1999   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2000   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2001   // NamedDecl
2002   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2003   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2004   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2005   // TypeDecl
2006   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
2007   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
2008   // TagDecl
2009   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
2010   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
2011   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
2012   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
2013   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
2014   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
2015   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2016   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2017   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
2018   // RecordDecl
2019   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // FlexibleArrayMember
2020   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // AnonymousStructUnion
2021   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasObjectMember
2022   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasVolatileMember
2023 
2024   // isNonTrivialToPrimitiveDefaultInitialize
2025   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2026   // isNonTrivialToPrimitiveCopy
2027   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2028   // isNonTrivialToPrimitiveDestroy
2029   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2030   // hasNonTrivialToPrimitiveDefaultInitializeCUnion
2031   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2032   // hasNonTrivialToPrimitiveDestructCUnion
2033   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2034   // hasNonTrivialToPrimitiveCopyCUnion
2035   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2036   // isParamDestroyedInCallee
2037   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2038   // getArgPassingRestrictions
2039   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));
2040 
2041   // DC
2042   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
2043   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
2044   DeclRecordAbbrev = Stream.EmitAbbrev(std::move(Abv));
2045 
2046   // Abbreviation for DECL_PARM_VAR
2047   Abv = std::make_shared<BitCodeAbbrev>();
2048   Abv->Add(BitCodeAbbrevOp(serialization::DECL_PARM_VAR));
2049   // Redeclarable
2050   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2051   // Decl
2052   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2053   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2054   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2055   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2056   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2057   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2058   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2059   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2060   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2061   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2062   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2063   // NamedDecl
2064   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2065   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2066   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2067   // ValueDecl
2068   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2069   // DeclaratorDecl
2070   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
2071   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
2072   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
2073   // VarDecl
2074   Abv->Add(BitCodeAbbrevOp(0));                       // SClass
2075   Abv->Add(BitCodeAbbrevOp(0));                       // TSCSpec
2076   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
2077   Abv->Add(BitCodeAbbrevOp(0));                       // ARCPseudoStrong
2078   Abv->Add(BitCodeAbbrevOp(0));                       // Linkage
2079   Abv->Add(BitCodeAbbrevOp(0));                       // HasInit
2080   Abv->Add(BitCodeAbbrevOp(0));                   // HasMemberSpecializationInfo
2081   // ParmVarDecl
2082   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsObjCMethodParameter
2083   Abv->Add(BitCodeAbbrevOp(0));                       // ScopeDepth
2084   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ScopeIndex
2085   Abv->Add(BitCodeAbbrevOp(0));                       // ObjCDeclQualifier
2086   Abv->Add(BitCodeAbbrevOp(0));                       // KNRPromoted
2087   Abv->Add(BitCodeAbbrevOp(0));                       // HasInheritedDefaultArg
2088   Abv->Add(BitCodeAbbrevOp(0));                   // HasUninstantiatedDefaultArg
2089   // Type Source Info
2090   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2091   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2092   DeclParmVarAbbrev = Stream.EmitAbbrev(std::move(Abv));
2093 
2094   // Abbreviation for DECL_TYPEDEF
2095   Abv = std::make_shared<BitCodeAbbrev>();
2096   Abv->Add(BitCodeAbbrevOp(serialization::DECL_TYPEDEF));
2097   // Redeclarable
2098   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2099   // Decl
2100   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2101   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2102   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2103   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2104   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2105   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isUsed
2106   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isReferenced
2107   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2108   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // C++ AccessSpecifier
2109   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2110   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2111   // NamedDecl
2112   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2113   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2114   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2115   // TypeDecl
2116   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
2117   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
2118   // TypedefDecl
2119   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2120   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2121   DeclTypedefAbbrev = Stream.EmitAbbrev(std::move(Abv));
2122 
2123   // Abbreviation for DECL_VAR
2124   Abv = std::make_shared<BitCodeAbbrev>();
2125   Abv->Add(BitCodeAbbrevOp(serialization::DECL_VAR));
2126   // Redeclarable
2127   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2128   // Decl
2129   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2130   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2131   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2132   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2133   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2134   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2135   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2136   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2137   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2138   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2139   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2140   // NamedDecl
2141   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2142   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2143   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2144   // ValueDecl
2145   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2146   // DeclaratorDecl
2147   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
2148   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
2149   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
2150   // VarDecl
2151   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // SClass
2152   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // TSCSpec
2153   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // InitStyle
2154   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isARCPseudoStrong
2155   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsThisDeclarationADemotedDefinition
2156   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isExceptionVariable
2157   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isNRVOVariable
2158   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCXXForRangeDecl
2159   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isObjCForDecl
2160   Abv->Add(BitCodeAbbrevOp(0));                         // isInline
2161   Abv->Add(BitCodeAbbrevOp(0));                         // isInlineSpecified
2162   Abv->Add(BitCodeAbbrevOp(0));                         // isConstexpr
2163   Abv->Add(BitCodeAbbrevOp(0));                         // isInitCapture
2164   Abv->Add(BitCodeAbbrevOp(0));                         // isPrevDeclInSameScope
2165   Abv->Add(BitCodeAbbrevOp(0));                         // ImplicitParamKind
2166   Abv->Add(BitCodeAbbrevOp(0));                         // EscapingByref
2167   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
2168   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // IsInitICE (local)
2169   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // VarKind (local enum)
2170   // Type Source Info
2171   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2172   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2173   DeclVarAbbrev = Stream.EmitAbbrev(std::move(Abv));
2174 
2175   // Abbreviation for DECL_CXX_METHOD
2176   Abv = std::make_shared<BitCodeAbbrev>();
2177   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CXX_METHOD));
2178   // RedeclarableDecl
2179   Abv->Add(BitCodeAbbrevOp(0));                         // CanonicalDecl
2180   // Decl
2181   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // DeclContext
2182   Abv->Add(BitCodeAbbrevOp(0));                         // LexicalDeclContext
2183   Abv->Add(BitCodeAbbrevOp(0));                         // Invalid
2184   Abv->Add(BitCodeAbbrevOp(0));                         // HasAttrs
2185   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Implicit
2186   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Used
2187   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Referenced
2188   Abv->Add(BitCodeAbbrevOp(0));                         // InObjCContainer
2189   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // Access
2190   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ModulePrivate
2191   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SubmoduleID
2192   // NamedDecl
2193   Abv->Add(BitCodeAbbrevOp(DeclarationName::Identifier)); // NameKind
2194   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Identifier
2195   Abv->Add(BitCodeAbbrevOp(0));                         // AnonDeclNumber
2196   // ValueDecl
2197   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Type
2198   // DeclaratorDecl
2199   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InnerLocStart
2200   Abv->Add(BitCodeAbbrevOp(0));                         // HasExtInfo
2201   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // TSIType
2202   // FunctionDecl
2203   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 11)); // IDNS
2204   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // StorageClass
2205   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Inline
2206   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // InlineSpecified
2207   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // VirtualAsWritten
2208   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Pure
2209   Abv->Add(BitCodeAbbrevOp(0));                         // HasInheritedProto
2210   Abv->Add(BitCodeAbbrevOp(1));                         // HasWrittenProto
2211   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Deleted
2212   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Trivial
2213   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // TrivialForCall
2214   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Defaulted
2215   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ExplicitlyDefaulted
2216   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ImplicitReturnZero
2217   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Constexpr
2218   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // UsesSEHTry
2219   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // SkippedBody
2220   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // MultiVersion
2221   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // LateParsed
2222   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
2223   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LocEnd
2224   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32)); // ODRHash
2225   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // TemplateKind
2226   // This Array slurps the rest of the record. Fortunately we want to encode
2227   // (nearly) all the remaining (variable number of) fields in the same way.
2228   //
2229   // This is the function template information if any, then
2230   //         NumParams and Params[] from FunctionDecl, and
2231   //         NumOverriddenMethods, OverriddenMethods[] from CXXMethodDecl.
2232   //
2233   //  Add an AbbrevOp for 'size then elements' and use it here.
2234   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2235   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2236   DeclCXXMethodAbbrev = Stream.EmitAbbrev(std::move(Abv));
2237 
2238   // Abbreviation for EXPR_DECL_REF
2239   Abv = std::make_shared<BitCodeAbbrev>();
2240   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_DECL_REF));
2241   //Stmt
2242   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsOMPStructuredBlock
2243   // Expr
2244   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2245   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2246   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2247   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2248   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2249   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2250   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2251   //DeclRefExpr
2252   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HasQualifier
2253   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //GetDeclFound
2254   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ExplicitTemplateArgs
2255   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HadMultipleCandidates
2256   Abv->Add(BitCodeAbbrevOp(0)); // RefersToEnclosingVariableOrCapture
2257   Abv->Add(BitCodeAbbrevOp(0)); // NonOdrUseReason
2258   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclRef
2259   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2260   DeclRefExprAbbrev = Stream.EmitAbbrev(std::move(Abv));
2261 
2262   // Abbreviation for EXPR_INTEGER_LITERAL
2263   Abv = std::make_shared<BitCodeAbbrev>();
2264   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_INTEGER_LITERAL));
2265   //Stmt
2266   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsOMPStructuredBlock
2267   // Expr
2268   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2269   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2270   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2271   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2272   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2273   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2274   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2275   //Integer Literal
2276   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2277   Abv->Add(BitCodeAbbrevOp(32));                      // Bit Width
2278   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Value
2279   IntegerLiteralAbbrev = Stream.EmitAbbrev(std::move(Abv));
2280 
2281   // Abbreviation for EXPR_CHARACTER_LITERAL
2282   Abv = std::make_shared<BitCodeAbbrev>();
2283   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_CHARACTER_LITERAL));
2284   //Stmt
2285   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsOMPStructuredBlock
2286   // Expr
2287   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2288   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2289   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2290   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2291   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2292   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2293   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2294   //Character Literal
2295   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getValue
2296   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2297   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // getKind
2298   CharacterLiteralAbbrev = Stream.EmitAbbrev(std::move(Abv));
2299 
2300   // Abbreviation for EXPR_IMPLICIT_CAST
2301   Abv = std::make_shared<BitCodeAbbrev>();
2302   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_IMPLICIT_CAST));
2303   // Stmt
2304   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsOMPStructuredBlock
2305   // Expr
2306   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2307   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2308   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2309   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2310   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2311   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2312   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2313   // CastExpr
2314   Abv->Add(BitCodeAbbrevOp(0)); // PathSize
2315   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 6)); // CastKind
2316   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // PartOfExplicitCast
2317   // ImplicitCastExpr
2318   ExprImplicitCastAbbrev = Stream.EmitAbbrev(std::move(Abv));
2319 
2320   Abv = std::make_shared<BitCodeAbbrev>();
2321   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_LEXICAL));
2322   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2323   DeclContextLexicalAbbrev = Stream.EmitAbbrev(std::move(Abv));
2324 
2325   Abv = std::make_shared<BitCodeAbbrev>();
2326   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_VISIBLE));
2327   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2328   DeclContextVisibleLookupAbbrev = Stream.EmitAbbrev(std::move(Abv));
2329 }
2330 
2331 /// isRequiredDecl - Check if this is a "required" Decl, which must be seen by
2332 /// consumers of the AST.
2333 ///
2334 /// Such decls will always be deserialized from the AST file, so we would like
2335 /// this to be as restrictive as possible. Currently the predicate is driven by
2336 /// code generation requirements, if other clients have a different notion of
2337 /// what is "required" then we may have to consider an alternate scheme where
2338 /// clients can iterate over the top-level decls and get information on them,
2339 /// without necessary deserializing them. We could explicitly require such
2340 /// clients to use a separate API call to "realize" the decl. This should be
2341 /// relatively painless since they would presumably only do it for top-level
2342 /// decls.
2343 static bool isRequiredDecl(const Decl *D, ASTContext &Context,
2344                            bool WritingModule) {
2345   // An ObjCMethodDecl is never considered as "required" because its
2346   // implementation container always is.
2347 
2348   // File scoped assembly or obj-c or OMP declare target implementation must be
2349   // seen.
2350   if (isa<FileScopeAsmDecl>(D) || isa<ObjCImplDecl>(D))
2351     return true;
2352 
2353   if (WritingModule && isPartOfPerModuleInitializer(D)) {
2354     // These declarations are part of the module initializer, and are emitted
2355     // if and when the module is imported, rather than being emitted eagerly.
2356     return false;
2357   }
2358 
2359   return Context.DeclMustBeEmitted(D);
2360 }
2361 
2362 void ASTWriter::WriteDecl(ASTContext &Context, Decl *D) {
2363   PrettyDeclStackTraceEntry CrashInfo(Context, D, SourceLocation(),
2364                                       "serializing");
2365 
2366   // Determine the ID for this declaration.
2367   serialization::DeclID ID;
2368   assert(!D->isFromASTFile() && "should not be emitting imported decl");
2369   serialization::DeclID &IDR = DeclIDs[D];
2370   if (IDR == 0)
2371     IDR = NextDeclID++;
2372 
2373   ID = IDR;
2374 
2375   assert(ID >= FirstDeclID && "invalid decl ID");
2376 
2377   RecordData Record;
2378   ASTDeclWriter W(*this, Context, Record);
2379 
2380   // Build a record for this declaration
2381   W.Visit(D);
2382 
2383   // Emit this declaration to the bitstream.
2384   uint64_t Offset = W.Emit(D);
2385 
2386   // Record the offset for this declaration
2387   SourceLocation Loc = D->getLocation();
2388   unsigned Index = ID - FirstDeclID;
2389   if (DeclOffsets.size() == Index)
2390     DeclOffsets.push_back(DeclOffset(Loc, Offset));
2391   else if (DeclOffsets.size() < Index) {
2392     // FIXME: Can/should this happen?
2393     DeclOffsets.resize(Index+1);
2394     DeclOffsets[Index].setLocation(Loc);
2395     DeclOffsets[Index].BitOffset = Offset;
2396   } else {
2397     llvm_unreachable("declarations should be emitted in ID order");
2398   }
2399 
2400   SourceManager &SM = Context.getSourceManager();
2401   if (Loc.isValid() && SM.isLocalSourceLocation(Loc))
2402     associateDeclWithFile(D, ID);
2403 
2404   // Note declarations that should be deserialized eagerly so that we can add
2405   // them to a record in the AST file later.
2406   if (isRequiredDecl(D, Context, WritingModule))
2407     EagerlyDeserializedDecls.push_back(ID);
2408 }
2409 
2410 void ASTRecordWriter::AddFunctionDefinition(const FunctionDecl *FD) {
2411   // Switch case IDs are per function body.
2412   Writer->ClearSwitchCaseIDs();
2413 
2414   assert(FD->doesThisDeclarationHaveABody());
2415   bool ModulesCodegen = false;
2416   if (Writer->WritingModule && !FD->isDependentContext()) {
2417     Optional<GVALinkage> Linkage;
2418     if (Writer->WritingModule->Kind == Module::ModuleInterfaceUnit) {
2419       // When building a C++ Modules TS module interface unit, a strong
2420       // definition in the module interface is provided by the compilation of
2421       // that module interface unit, not by its users. (Inline functions are
2422       // still emitted in module users.)
2423       Linkage = Writer->Context->GetGVALinkageForFunction(FD);
2424       ModulesCodegen = *Linkage == GVA_StrongExternal;
2425     }
2426     if (Writer->Context->getLangOpts().ModulesCodegen) {
2427       // Under -fmodules-codegen, codegen is performed for all non-internal,
2428       // non-always_inline functions.
2429       if (!FD->hasAttr<AlwaysInlineAttr>()) {
2430         if (!Linkage)
2431           Linkage = Writer->Context->GetGVALinkageForFunction(FD);
2432         ModulesCodegen = *Linkage != GVA_Internal;
2433       }
2434     }
2435   }
2436   Record->push_back(ModulesCodegen);
2437   if (ModulesCodegen)
2438     Writer->ModularCodegenDecls.push_back(Writer->GetDeclRef(FD));
2439   if (auto *CD = dyn_cast<CXXConstructorDecl>(FD)) {
2440     Record->push_back(CD->getNumCtorInitializers());
2441     if (CD->getNumCtorInitializers())
2442       AddCXXCtorInitializers(
2443           llvm::makeArrayRef(CD->init_begin(), CD->init_end()));
2444   }
2445   AddStmt(FD->getBody());
2446 }
2447