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