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