1 //===--- ASTWriterDecl.cpp - Declaration Serialization --------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 //  This file implements serialization for Declarations.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "ASTCommon.h"
14 #include "clang/AST/Attr.h"
15 #include "clang/AST/DeclCXX.h"
16 #include "clang/AST/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/ASTRecordWriter.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 VisitUnresolvedUsingIfExistsDecl(UnresolvedUsingIfExistsDecl *D);
72     void VisitTagDecl(TagDecl *D);
73     void VisitEnumDecl(EnumDecl *D);
74     void VisitRecordDecl(RecordDecl *D);
75     void VisitCXXRecordDecl(CXXRecordDecl *D);
76     void VisitClassTemplateSpecializationDecl(
77                                             ClassTemplateSpecializationDecl *D);
78     void VisitClassTemplatePartialSpecializationDecl(
79                                      ClassTemplatePartialSpecializationDecl *D);
80     void VisitVarTemplateSpecializationDecl(VarTemplateSpecializationDecl *D);
81     void VisitVarTemplatePartialSpecializationDecl(
82         VarTemplatePartialSpecializationDecl *D);
83     void VisitClassScopeFunctionSpecializationDecl(
84                                        ClassScopeFunctionSpecializationDecl *D);
85     void VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
86     void VisitValueDecl(ValueDecl *D);
87     void VisitEnumConstantDecl(EnumConstantDecl *D);
88     void VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D);
89     void VisitDeclaratorDecl(DeclaratorDecl *D);
90     void VisitFunctionDecl(FunctionDecl *D);
91     void VisitCXXDeductionGuideDecl(CXXDeductionGuideDecl *D);
92     void VisitCXXMethodDecl(CXXMethodDecl *D);
93     void VisitCXXConstructorDecl(CXXConstructorDecl *D);
94     void VisitCXXDestructorDecl(CXXDestructorDecl *D);
95     void VisitCXXConversionDecl(CXXConversionDecl *D);
96     void VisitFieldDecl(FieldDecl *D);
97     void VisitMSPropertyDecl(MSPropertyDecl *D);
98     void VisitMSGuidDecl(MSGuidDecl *D);
99     void VisitTemplateParamObjectDecl(TemplateParamObjectDecl *D);
100     void VisitIndirectFieldDecl(IndirectFieldDecl *D);
101     void VisitVarDecl(VarDecl *D);
102     void VisitImplicitParamDecl(ImplicitParamDecl *D);
103     void VisitParmVarDecl(ParmVarDecl *D);
104     void VisitDecompositionDecl(DecompositionDecl *D);
105     void VisitBindingDecl(BindingDecl *D);
106     void VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
107     void VisitTemplateDecl(TemplateDecl *D);
108     void VisitConceptDecl(ConceptDecl *D);
109     void VisitRequiresExprBodyDecl(RequiresExprBodyDecl *D);
110     void VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D);
111     void VisitClassTemplateDecl(ClassTemplateDecl *D);
112     void VisitVarTemplateDecl(VarTemplateDecl *D);
113     void VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
114     void VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
115     void VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D);
116     void VisitUsingDecl(UsingDecl *D);
117     void VisitUsingEnumDecl(UsingEnumDecl *D);
118     void VisitUsingPackDecl(UsingPackDecl *D);
119     void VisitUsingShadowDecl(UsingShadowDecl *D);
120     void VisitConstructorUsingShadowDecl(ConstructorUsingShadowDecl *D);
121     void VisitLinkageSpecDecl(LinkageSpecDecl *D);
122     void VisitExportDecl(ExportDecl *D);
123     void VisitFileScopeAsmDecl(FileScopeAsmDecl *D);
124     void VisitImportDecl(ImportDecl *D);
125     void VisitAccessSpecDecl(AccessSpecDecl *D);
126     void VisitFriendDecl(FriendDecl *D);
127     void VisitFriendTemplateDecl(FriendTemplateDecl *D);
128     void VisitStaticAssertDecl(StaticAssertDecl *D);
129     void VisitBlockDecl(BlockDecl *D);
130     void VisitCapturedDecl(CapturedDecl *D);
131     void VisitEmptyDecl(EmptyDecl *D);
132     void VisitLifetimeExtendedTemporaryDecl(LifetimeExtendedTemporaryDecl *D);
133 
134     void VisitDeclContext(DeclContext *DC);
135     template <typename T> void VisitRedeclarable(Redeclarable<T> *D);
136 
137 
138     // FIXME: Put in the same order is DeclNodes.td?
139     void VisitObjCMethodDecl(ObjCMethodDecl *D);
140     void VisitObjCTypeParamDecl(ObjCTypeParamDecl *D);
141     void VisitObjCContainerDecl(ObjCContainerDecl *D);
142     void VisitObjCInterfaceDecl(ObjCInterfaceDecl *D);
143     void VisitObjCIvarDecl(ObjCIvarDecl *D);
144     void VisitObjCProtocolDecl(ObjCProtocolDecl *D);
145     void VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D);
146     void VisitObjCCategoryDecl(ObjCCategoryDecl *D);
147     void VisitObjCImplDecl(ObjCImplDecl *D);
148     void VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D);
149     void VisitObjCImplementationDecl(ObjCImplementationDecl *D);
150     void VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D);
151     void VisitObjCPropertyDecl(ObjCPropertyDecl *D);
152     void VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D);
153     void VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D);
154     void VisitOMPAllocateDecl(OMPAllocateDecl *D);
155     void VisitOMPRequiresDecl(OMPRequiresDecl *D);
156     void VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D);
157     void VisitOMPDeclareMapperDecl(OMPDeclareMapperDecl *D);
158     void VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D);
159 
160     /// Add an Objective-C type parameter list to the given record.
161     void AddObjCTypeParamList(ObjCTypeParamList *typeParams) {
162       // Empty type parameter list.
163       if (!typeParams) {
164         Record.push_back(0);
165         return;
166       }
167 
168       Record.push_back(typeParams->size());
169       for (auto typeParam : *typeParams) {
170         Record.AddDeclRef(typeParam);
171       }
172       Record.AddSourceLocation(typeParams->getLAngleLoc());
173       Record.AddSourceLocation(typeParams->getRAngleLoc());
174     }
175 
176     /// Add to the record the first declaration from each module file that
177     /// provides a declaration of D. The intent is to provide a sufficient
178     /// set such that reloading this set will load all current redeclarations.
179     void AddFirstDeclFromEachModule(const Decl *D, bool IncludeLocal) {
180       llvm::MapVector<ModuleFile*, const Decl*> Firsts;
181       // FIXME: We can skip entries that we know are implied by others.
182       for (const Decl *R = D->getMostRecentDecl(); R; R = R->getPreviousDecl()) {
183         if (R->isFromASTFile())
184           Firsts[Writer.Chain->getOwningModuleFile(R)] = R;
185         else if (IncludeLocal)
186           Firsts[nullptr] = R;
187       }
188       for (const auto &F : Firsts)
189         Record.AddDeclRef(F.second);
190     }
191 
192     /// Get the specialization decl from an entry in the specialization list.
193     template <typename EntryType>
194     typename RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::DeclType *
195     getSpecializationDecl(EntryType &T) {
196       return RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::getDecl(&T);
197     }
198 
199     /// Get the list of partial specializations from a template's common ptr.
200     template<typename T>
201     decltype(T::PartialSpecializations) &getPartialSpecializations(T *Common) {
202       return Common->PartialSpecializations;
203     }
204     ArrayRef<Decl> getPartialSpecializations(FunctionTemplateDecl::Common *) {
205       return None;
206     }
207 
208     template<typename DeclTy>
209     void AddTemplateSpecializations(DeclTy *D) {
210       auto *Common = D->getCommonPtr();
211 
212       // If we have any lazy specializations, and the external AST source is
213       // our chained AST reader, we can just write out the DeclIDs. Otherwise,
214       // we need to resolve them to actual declarations.
215       if (Writer.Chain != Writer.Context->getExternalSource() &&
216           Common->LazySpecializations) {
217         D->LoadLazySpecializations();
218         assert(!Common->LazySpecializations);
219       }
220 
221       ArrayRef<DeclID> LazySpecializations;
222       if (auto *LS = Common->LazySpecializations)
223         LazySpecializations = llvm::makeArrayRef(LS + 1, LS[0]);
224 
225       // Add a slot to the record for the number of specializations.
226       unsigned I = Record.size();
227       Record.push_back(0);
228 
229       // AddFirstDeclFromEachModule might trigger deserialization, invalidating
230       // *Specializations iterators.
231       llvm::SmallVector<const Decl*, 16> Specs;
232       for (auto &Entry : Common->Specializations)
233         Specs.push_back(getSpecializationDecl(Entry));
234       for (auto &Entry : getPartialSpecializations(Common))
235         Specs.push_back(getSpecializationDecl(Entry));
236 
237       for (auto *D : Specs) {
238         assert(D->isCanonicalDecl() && "non-canonical decl in set");
239         AddFirstDeclFromEachModule(D, /*IncludeLocal*/true);
240       }
241       Record.append(LazySpecializations.begin(), LazySpecializations.end());
242 
243       // Update the size entry we added earlier.
244       Record[I] = Record.size() - I - 1;
245     }
246 
247     /// Ensure that this template specialization is associated with the specified
248     /// template on reload.
249     void RegisterTemplateSpecialization(const Decl *Template,
250                                         const Decl *Specialization) {
251       Template = Template->getCanonicalDecl();
252 
253       // If the canonical template is local, we'll write out this specialization
254       // when we emit it.
255       // FIXME: We can do the same thing if there is any local declaration of
256       // the template, to avoid emitting an update record.
257       if (!Template->isFromASTFile())
258         return;
259 
260       // We only need to associate the first local declaration of the
261       // specialization. The other declarations will get pulled in by it.
262       if (Writer.getFirstLocalDecl(Specialization) != Specialization)
263         return;
264 
265       Writer.DeclUpdates[Template].push_back(ASTWriter::DeclUpdate(
266           UPD_CXX_ADDED_TEMPLATE_SPECIALIZATION, Specialization));
267     }
268   };
269 }
270 
271 void ASTDeclWriter::Visit(Decl *D) {
272   DeclVisitor<ASTDeclWriter>::Visit(D);
273 
274   // Source locations require array (variable-length) abbreviations.  The
275   // abbreviation infrastructure requires that arrays are encoded last, so
276   // we handle it here in the case of those classes derived from DeclaratorDecl
277   if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D)) {
278     if (auto *TInfo = DD->getTypeSourceInfo())
279       Record.AddTypeLoc(TInfo->getTypeLoc());
280   }
281 
282   // Handle FunctionDecl's body here and write it after all other Stmts/Exprs
283   // have been written. We want it last because we will not read it back when
284   // retrieving it from the AST, we'll just lazily set the offset.
285   if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
286     Record.push_back(FD->doesThisDeclarationHaveABody());
287     if (FD->doesThisDeclarationHaveABody())
288       Record.AddFunctionDefinition(FD);
289   }
290 
291   // If this declaration is also a DeclContext, write blocks for the
292   // declarations that lexically stored inside its context and those
293   // declarations that are visible from its context.
294   if (DeclContext *DC = dyn_cast<DeclContext>(D))
295     VisitDeclContext(DC);
296 }
297 
298 void ASTDeclWriter::VisitDecl(Decl *D) {
299   Record.AddDeclRef(cast_or_null<Decl>(D->getDeclContext()));
300   if (D->getDeclContext() != D->getLexicalDeclContext())
301     Record.AddDeclRef(cast_or_null<Decl>(D->getLexicalDeclContext()));
302   else
303     Record.push_back(0);
304   Record.push_back(D->isInvalidDecl());
305   Record.push_back(D->hasAttrs());
306   if (D->hasAttrs())
307     Record.AddAttributes(D->getAttrs());
308   Record.push_back(D->isImplicit());
309   Record.push_back(D->isUsed(false));
310   Record.push_back(D->isReferenced());
311   Record.push_back(D->isTopLevelDeclInObjCContainer());
312   Record.push_back(D->getAccess());
313   Record.push_back(D->isModulePrivate());
314   Record.push_back(Writer.getSubmoduleID(D->getOwningModule()));
315 
316   // If this declaration injected a name into a context different from its
317   // lexical context, and that context is an imported namespace, we need to
318   // update its visible declarations to include this name.
319   //
320   // This happens when we instantiate a class with a friend declaration or a
321   // function with a local extern declaration, for instance.
322   //
323   // FIXME: Can we handle this in AddedVisibleDecl instead?
324   if (D->isOutOfLine()) {
325     auto *DC = D->getDeclContext();
326     while (auto *NS = dyn_cast<NamespaceDecl>(DC->getRedeclContext())) {
327       if (!NS->isFromASTFile())
328         break;
329       Writer.UpdatedDeclContexts.insert(NS->getPrimaryContext());
330       if (!NS->isInlineNamespace())
331         break;
332       DC = NS->getParent();
333     }
334   }
335 }
336 
337 void ASTDeclWriter::VisitPragmaCommentDecl(PragmaCommentDecl *D) {
338   StringRef Arg = D->getArg();
339   Record.push_back(Arg.size());
340   VisitDecl(D);
341   Record.AddSourceLocation(D->getBeginLoc());
342   Record.push_back(D->getCommentKind());
343   Record.AddString(Arg);
344   Code = serialization::DECL_PRAGMA_COMMENT;
345 }
346 
347 void ASTDeclWriter::VisitPragmaDetectMismatchDecl(
348     PragmaDetectMismatchDecl *D) {
349   StringRef Name = D->getName();
350   StringRef Value = D->getValue();
351   Record.push_back(Name.size() + 1 + Value.size());
352   VisitDecl(D);
353   Record.AddSourceLocation(D->getBeginLoc());
354   Record.AddString(Name);
355   Record.AddString(Value);
356   Code = serialization::DECL_PRAGMA_DETECT_MISMATCH;
357 }
358 
359 void ASTDeclWriter::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
360   llvm_unreachable("Translation units aren't directly serialized");
361 }
362 
363 void ASTDeclWriter::VisitNamedDecl(NamedDecl *D) {
364   VisitDecl(D);
365   Record.AddDeclarationName(D->getDeclName());
366   Record.push_back(needsAnonymousDeclarationNumber(D)
367                        ? Writer.getAnonymousDeclarationNumber(D)
368                        : 0);
369 }
370 
371 void ASTDeclWriter::VisitTypeDecl(TypeDecl *D) {
372   VisitNamedDecl(D);
373   Record.AddSourceLocation(D->getBeginLoc());
374   Record.AddTypeRef(QualType(D->getTypeForDecl(), 0));
375 }
376 
377 void ASTDeclWriter::VisitTypedefNameDecl(TypedefNameDecl *D) {
378   VisitRedeclarable(D);
379   VisitTypeDecl(D);
380   Record.AddTypeSourceInfo(D->getTypeSourceInfo());
381   Record.push_back(D->isModed());
382   if (D->isModed())
383     Record.AddTypeRef(D->getUnderlyingType());
384   Record.AddDeclRef(D->getAnonDeclWithTypedefName(false));
385 }
386 
387 void ASTDeclWriter::VisitTypedefDecl(TypedefDecl *D) {
388   VisitTypedefNameDecl(D);
389   if (D->getDeclContext() == D->getLexicalDeclContext() &&
390       !D->hasAttrs() &&
391       !D->isImplicit() &&
392       D->getFirstDecl() == D->getMostRecentDecl() &&
393       !D->isInvalidDecl() &&
394       !D->isTopLevelDeclInObjCContainer() &&
395       !D->isModulePrivate() &&
396       !needsAnonymousDeclarationNumber(D) &&
397       D->getDeclName().getNameKind() == DeclarationName::Identifier)
398     AbbrevToUse = Writer.getDeclTypedefAbbrev();
399 
400   Code = serialization::DECL_TYPEDEF;
401 }
402 
403 void ASTDeclWriter::VisitTypeAliasDecl(TypeAliasDecl *D) {
404   VisitTypedefNameDecl(D);
405   Record.AddDeclRef(D->getDescribedAliasTemplate());
406   Code = serialization::DECL_TYPEALIAS;
407 }
408 
409 void ASTDeclWriter::VisitTagDecl(TagDecl *D) {
410   VisitRedeclarable(D);
411   VisitTypeDecl(D);
412   Record.push_back(D->getIdentifierNamespace());
413   Record.push_back((unsigned)D->getTagKind()); // FIXME: stable encoding
414   if (!isa<CXXRecordDecl>(D))
415     Record.push_back(D->isCompleteDefinition());
416   Record.push_back(D->isEmbeddedInDeclarator());
417   Record.push_back(D->isFreeStanding());
418   Record.push_back(D->isCompleteDefinitionRequired());
419   Record.AddSourceRange(D->getBraceRange());
420 
421   if (D->hasExtInfo()) {
422     Record.push_back(1);
423     Record.AddQualifierInfo(*D->getExtInfo());
424   } else if (auto *TD = D->getTypedefNameForAnonDecl()) {
425     Record.push_back(2);
426     Record.AddDeclRef(TD);
427     Record.AddIdentifierRef(TD->getDeclName().getAsIdentifierInfo());
428   } else {
429     Record.push_back(0);
430   }
431 }
432 
433 void ASTDeclWriter::VisitEnumDecl(EnumDecl *D) {
434   VisitTagDecl(D);
435   Record.AddTypeSourceInfo(D->getIntegerTypeSourceInfo());
436   if (!D->getIntegerTypeSourceInfo())
437     Record.AddTypeRef(D->getIntegerType());
438   Record.AddTypeRef(D->getPromotionType());
439   Record.push_back(D->getNumPositiveBits());
440   Record.push_back(D->getNumNegativeBits());
441   Record.push_back(D->isScoped());
442   Record.push_back(D->isScopedUsingClassTag());
443   Record.push_back(D->isFixed());
444   Record.push_back(D->getODRHash());
445 
446   if (MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo()) {
447     Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
448     Record.push_back(MemberInfo->getTemplateSpecializationKind());
449     Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
450   } else {
451     Record.AddDeclRef(nullptr);
452   }
453 
454   if (D->getDeclContext() == D->getLexicalDeclContext() &&
455       !D->hasAttrs() &&
456       !D->isImplicit() &&
457       !D->isUsed(false) &&
458       !D->hasExtInfo() &&
459       !D->getTypedefNameForAnonDecl() &&
460       D->getFirstDecl() == D->getMostRecentDecl() &&
461       !D->isInvalidDecl() &&
462       !D->isReferenced() &&
463       !D->isTopLevelDeclInObjCContainer() &&
464       D->getAccess() == AS_none &&
465       !D->isModulePrivate() &&
466       !CXXRecordDecl::classofKind(D->getKind()) &&
467       !D->getIntegerTypeSourceInfo() &&
468       !D->getMemberSpecializationInfo() &&
469       !needsAnonymousDeclarationNumber(D) &&
470       D->getDeclName().getNameKind() == DeclarationName::Identifier)
471     AbbrevToUse = Writer.getDeclEnumAbbrev();
472 
473   Code = serialization::DECL_ENUM;
474 }
475 
476 void ASTDeclWriter::VisitRecordDecl(RecordDecl *D) {
477   VisitTagDecl(D);
478   Record.push_back(D->hasFlexibleArrayMember());
479   Record.push_back(D->isAnonymousStructOrUnion());
480   Record.push_back(D->hasObjectMember());
481   Record.push_back(D->hasVolatileMember());
482   Record.push_back(D->isNonTrivialToPrimitiveDefaultInitialize());
483   Record.push_back(D->isNonTrivialToPrimitiveCopy());
484   Record.push_back(D->isNonTrivialToPrimitiveDestroy());
485   Record.push_back(D->hasNonTrivialToPrimitiveDefaultInitializeCUnion());
486   Record.push_back(D->hasNonTrivialToPrimitiveDestructCUnion());
487   Record.push_back(D->hasNonTrivialToPrimitiveCopyCUnion());
488   Record.push_back(D->isParamDestroyedInCallee());
489   Record.push_back(D->getArgPassingRestrictions());
490 
491   if (D->getDeclContext() == D->getLexicalDeclContext() &&
492       !D->hasAttrs() &&
493       !D->isImplicit() &&
494       !D->isUsed(false) &&
495       !D->hasExtInfo() &&
496       !D->getTypedefNameForAnonDecl() &&
497       D->getFirstDecl() == D->getMostRecentDecl() &&
498       !D->isInvalidDecl() &&
499       !D->isReferenced() &&
500       !D->isTopLevelDeclInObjCContainer() &&
501       D->getAccess() == AS_none &&
502       !D->isModulePrivate() &&
503       !CXXRecordDecl::classofKind(D->getKind()) &&
504       !needsAnonymousDeclarationNumber(D) &&
505       D->getDeclName().getNameKind() == DeclarationName::Identifier)
506     AbbrevToUse = Writer.getDeclRecordAbbrev();
507 
508   Code = serialization::DECL_RECORD;
509 }
510 
511 void ASTDeclWriter::VisitValueDecl(ValueDecl *D) {
512   VisitNamedDecl(D);
513   Record.AddTypeRef(D->getType());
514 }
515 
516 void ASTDeclWriter::VisitEnumConstantDecl(EnumConstantDecl *D) {
517   VisitValueDecl(D);
518   Record.push_back(D->getInitExpr()? 1 : 0);
519   if (D->getInitExpr())
520     Record.AddStmt(D->getInitExpr());
521   Record.AddAPSInt(D->getInitVal());
522 
523   Code = serialization::DECL_ENUM_CONSTANT;
524 }
525 
526 void ASTDeclWriter::VisitDeclaratorDecl(DeclaratorDecl *D) {
527   VisitValueDecl(D);
528   Record.AddSourceLocation(D->getInnerLocStart());
529   Record.push_back(D->hasExtInfo());
530   if (D->hasExtInfo()) {
531     DeclaratorDecl::ExtInfo *Info = D->getExtInfo();
532     Record.AddQualifierInfo(*Info);
533     Record.AddStmt(Info->TrailingRequiresClause);
534   }
535   // The location information is deferred until the end of the record.
536   Record.AddTypeRef(D->getTypeSourceInfo() ? D->getTypeSourceInfo()->getType()
537                                            : QualType());
538 }
539 
540 void ASTDeclWriter::VisitFunctionDecl(FunctionDecl *D) {
541   VisitRedeclarable(D);
542   VisitDeclaratorDecl(D);
543   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
544   Record.push_back(D->getIdentifierNamespace());
545 
546   // FunctionDecl's body is handled last at ASTWriterDecl::Visit,
547   // after everything else is written.
548   Record.push_back(static_cast<int>(D->getStorageClass())); // FIXME: stable encoding
549   Record.push_back(D->isInlineSpecified());
550   Record.push_back(D->isInlined());
551   Record.push_back(D->isVirtualAsWritten());
552   Record.push_back(D->isPure());
553   Record.push_back(D->hasInheritedPrototype());
554   Record.push_back(D->hasWrittenPrototype());
555   Record.push_back(D->isDeletedBit());
556   Record.push_back(D->isTrivial());
557   Record.push_back(D->isTrivialForCall());
558   Record.push_back(D->isDefaulted());
559   Record.push_back(D->isExplicitlyDefaulted());
560   Record.push_back(D->hasImplicitReturnZero());
561   Record.push_back(static_cast<uint64_t>(D->getConstexprKind()));
562   Record.push_back(D->usesSEHTry());
563   Record.push_back(D->hasSkippedBody());
564   Record.push_back(D->isMultiVersion());
565   Record.push_back(D->isLateTemplateParsed());
566   Record.push_back(D->getLinkageInternal());
567   Record.AddSourceLocation(D->getEndLoc());
568 
569   Record.push_back(D->getODRHash());
570 
571   if (D->isDefaulted()) {
572     if (auto *FDI = D->getDefaultedFunctionInfo()) {
573       Record.push_back(FDI->getUnqualifiedLookups().size());
574       for (DeclAccessPair P : FDI->getUnqualifiedLookups()) {
575         Record.AddDeclRef(P.getDecl());
576         Record.push_back(P.getAccess());
577       }
578     } else {
579       Record.push_back(0);
580     }
581   }
582 
583   Record.push_back(D->getTemplatedKind());
584   switch (D->getTemplatedKind()) {
585   case FunctionDecl::TK_NonTemplate:
586     break;
587   case FunctionDecl::TK_FunctionTemplate:
588     Record.AddDeclRef(D->getDescribedFunctionTemplate());
589     break;
590   case FunctionDecl::TK_MemberSpecialization: {
591     MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo();
592     Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
593     Record.push_back(MemberInfo->getTemplateSpecializationKind());
594     Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
595     break;
596   }
597   case FunctionDecl::TK_FunctionTemplateSpecialization: {
598     FunctionTemplateSpecializationInfo *
599       FTSInfo = D->getTemplateSpecializationInfo();
600 
601     RegisterTemplateSpecialization(FTSInfo->getTemplate(), D);
602 
603     Record.AddDeclRef(FTSInfo->getTemplate());
604     Record.push_back(FTSInfo->getTemplateSpecializationKind());
605 
606     // Template arguments.
607     Record.AddTemplateArgumentList(FTSInfo->TemplateArguments);
608 
609     // Template args as written.
610     Record.push_back(FTSInfo->TemplateArgumentsAsWritten != nullptr);
611     if (FTSInfo->TemplateArgumentsAsWritten) {
612       Record.push_back(FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs);
613       for (int i=0, e = FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs;
614              i!=e; ++i)
615         Record.AddTemplateArgumentLoc(
616             (*FTSInfo->TemplateArgumentsAsWritten)[i]);
617       Record.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->LAngleLoc);
618       Record.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->RAngleLoc);
619     }
620 
621     Record.AddSourceLocation(FTSInfo->getPointOfInstantiation());
622 
623     if (MemberSpecializationInfo *MemberInfo =
624         FTSInfo->getMemberSpecializationInfo()) {
625       Record.push_back(1);
626       Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
627       Record.push_back(MemberInfo->getTemplateSpecializationKind());
628       Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
629     } else {
630       Record.push_back(0);
631     }
632 
633     if (D->isCanonicalDecl()) {
634       // Write the template that contains the specializations set. We will
635       // add a FunctionTemplateSpecializationInfo to it when reading.
636       Record.AddDeclRef(FTSInfo->getTemplate()->getCanonicalDecl());
637     }
638     break;
639   }
640   case FunctionDecl::TK_DependentFunctionTemplateSpecialization: {
641     DependentFunctionTemplateSpecializationInfo *
642       DFTSInfo = D->getDependentSpecializationInfo();
643 
644     // Templates.
645     Record.push_back(DFTSInfo->getNumTemplates());
646     for (int i=0, e = DFTSInfo->getNumTemplates(); i != e; ++i)
647       Record.AddDeclRef(DFTSInfo->getTemplate(i));
648 
649     // Templates args.
650     Record.push_back(DFTSInfo->getNumTemplateArgs());
651     for (int i=0, e = DFTSInfo->getNumTemplateArgs(); i != e; ++i)
652       Record.AddTemplateArgumentLoc(DFTSInfo->getTemplateArg(i));
653     Record.AddSourceLocation(DFTSInfo->getLAngleLoc());
654     Record.AddSourceLocation(DFTSInfo->getRAngleLoc());
655     break;
656   }
657   }
658 
659   Record.push_back(D->param_size());
660   for (auto P : D->parameters())
661     Record.AddDeclRef(P);
662   Code = serialization::DECL_FUNCTION;
663 }
664 
665 static void addExplicitSpecifier(ExplicitSpecifier ES,
666                                  ASTRecordWriter &Record) {
667   uint64_t Kind = static_cast<uint64_t>(ES.getKind());
668   Kind = Kind << 1 | static_cast<bool>(ES.getExpr());
669   Record.push_back(Kind);
670   if (ES.getExpr()) {
671     Record.AddStmt(ES.getExpr());
672   }
673 }
674 
675 void ASTDeclWriter::VisitCXXDeductionGuideDecl(CXXDeductionGuideDecl *D) {
676   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
677   Record.AddDeclRef(D->Ctor);
678   VisitFunctionDecl(D);
679   Record.push_back(D->isCopyDeductionCandidate());
680   Code = serialization::DECL_CXX_DEDUCTION_GUIDE;
681 }
682 
683 void ASTDeclWriter::VisitObjCMethodDecl(ObjCMethodDecl *D) {
684   VisitNamedDecl(D);
685   // FIXME: convert to LazyStmtPtr?
686   // Unlike C/C++, method bodies will never be in header files.
687   bool HasBodyStuff = D->getBody() != nullptr;
688   Record.push_back(HasBodyStuff);
689   if (HasBodyStuff) {
690     Record.AddStmt(D->getBody());
691   }
692   Record.AddDeclRef(D->getSelfDecl());
693   Record.AddDeclRef(D->getCmdDecl());
694   Record.push_back(D->isInstanceMethod());
695   Record.push_back(D->isVariadic());
696   Record.push_back(D->isPropertyAccessor());
697   Record.push_back(D->isSynthesizedAccessorStub());
698   Record.push_back(D->isDefined());
699   Record.push_back(D->isOverriding());
700   Record.push_back(D->hasSkippedBody());
701 
702   Record.push_back(D->isRedeclaration());
703   Record.push_back(D->hasRedeclaration());
704   if (D->hasRedeclaration()) {
705     assert(Context.getObjCMethodRedeclaration(D));
706     Record.AddDeclRef(Context.getObjCMethodRedeclaration(D));
707   }
708 
709   // FIXME: stable encoding for @required/@optional
710   Record.push_back(D->getImplementationControl());
711   // FIXME: stable encoding for in/out/inout/bycopy/byref/oneway/nullability
712   Record.push_back(D->getObjCDeclQualifier());
713   Record.push_back(D->hasRelatedResultType());
714   Record.AddTypeRef(D->getReturnType());
715   Record.AddTypeSourceInfo(D->getReturnTypeSourceInfo());
716   Record.AddSourceLocation(D->getEndLoc());
717   Record.push_back(D->param_size());
718   for (const auto *P : D->parameters())
719     Record.AddDeclRef(P);
720 
721   Record.push_back(D->getSelLocsKind());
722   unsigned NumStoredSelLocs = D->getNumStoredSelLocs();
723   SourceLocation *SelLocs = D->getStoredSelLocs();
724   Record.push_back(NumStoredSelLocs);
725   for (unsigned i = 0; i != NumStoredSelLocs; ++i)
726     Record.AddSourceLocation(SelLocs[i]);
727 
728   Code = serialization::DECL_OBJC_METHOD;
729 }
730 
731 void ASTDeclWriter::VisitObjCTypeParamDecl(ObjCTypeParamDecl *D) {
732   VisitTypedefNameDecl(D);
733   Record.push_back(D->Variance);
734   Record.push_back(D->Index);
735   Record.AddSourceLocation(D->VarianceLoc);
736   Record.AddSourceLocation(D->ColonLoc);
737 
738   Code = serialization::DECL_OBJC_TYPE_PARAM;
739 }
740 
741 void ASTDeclWriter::VisitObjCContainerDecl(ObjCContainerDecl *D) {
742   VisitNamedDecl(D);
743   Record.AddSourceLocation(D->getAtStartLoc());
744   Record.AddSourceRange(D->getAtEndRange());
745   // Abstract class (no need to define a stable serialization::DECL code).
746 }
747 
748 void ASTDeclWriter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
749   VisitRedeclarable(D);
750   VisitObjCContainerDecl(D);
751   Record.AddTypeRef(QualType(D->getTypeForDecl(), 0));
752   AddObjCTypeParamList(D->TypeParamList);
753 
754   Record.push_back(D->isThisDeclarationADefinition());
755   if (D->isThisDeclarationADefinition()) {
756     // Write the DefinitionData
757     ObjCInterfaceDecl::DefinitionData &Data = D->data();
758 
759     Record.AddTypeSourceInfo(D->getSuperClassTInfo());
760     Record.AddSourceLocation(D->getEndOfDefinitionLoc());
761     Record.push_back(Data.HasDesignatedInitializers);
762 
763     // Write out the protocols that are directly referenced by the @interface.
764     Record.push_back(Data.ReferencedProtocols.size());
765     for (const auto *P : D->protocols())
766       Record.AddDeclRef(P);
767     for (const auto &PL : D->protocol_locs())
768       Record.AddSourceLocation(PL);
769 
770     // Write out the protocols that are transitively referenced.
771     Record.push_back(Data.AllReferencedProtocols.size());
772     for (ObjCList<ObjCProtocolDecl>::iterator
773               P = Data.AllReferencedProtocols.begin(),
774            PEnd = Data.AllReferencedProtocols.end();
775          P != PEnd; ++P)
776       Record.AddDeclRef(*P);
777 
778 
779     if (ObjCCategoryDecl *Cat = D->getCategoryListRaw()) {
780       // Ensure that we write out the set of categories for this class.
781       Writer.ObjCClassesWithCategories.insert(D);
782 
783       // Make sure that the categories get serialized.
784       for (; Cat; Cat = Cat->getNextClassCategoryRaw())
785         (void)Writer.GetDeclRef(Cat);
786     }
787   }
788 
789   Code = serialization::DECL_OBJC_INTERFACE;
790 }
791 
792 void ASTDeclWriter::VisitObjCIvarDecl(ObjCIvarDecl *D) {
793   VisitFieldDecl(D);
794   // FIXME: stable encoding for @public/@private/@protected/@package
795   Record.push_back(D->getAccessControl());
796   Record.push_back(D->getSynthesize());
797 
798   if (D->getDeclContext() == D->getLexicalDeclContext() &&
799       !D->hasAttrs() &&
800       !D->isImplicit() &&
801       !D->isUsed(false) &&
802       !D->isInvalidDecl() &&
803       !D->isReferenced() &&
804       !D->isModulePrivate() &&
805       !D->getBitWidth() &&
806       !D->hasExtInfo() &&
807       D->getDeclName())
808     AbbrevToUse = Writer.getDeclObjCIvarAbbrev();
809 
810   Code = serialization::DECL_OBJC_IVAR;
811 }
812 
813 void ASTDeclWriter::VisitObjCProtocolDecl(ObjCProtocolDecl *D) {
814   VisitRedeclarable(D);
815   VisitObjCContainerDecl(D);
816 
817   Record.push_back(D->isThisDeclarationADefinition());
818   if (D->isThisDeclarationADefinition()) {
819     Record.push_back(D->protocol_size());
820     for (const auto *I : D->protocols())
821       Record.AddDeclRef(I);
822     for (const auto &PL : D->protocol_locs())
823       Record.AddSourceLocation(PL);
824   }
825 
826   Code = serialization::DECL_OBJC_PROTOCOL;
827 }
828 
829 void ASTDeclWriter::VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D) {
830   VisitFieldDecl(D);
831   Code = serialization::DECL_OBJC_AT_DEFS_FIELD;
832 }
833 
834 void ASTDeclWriter::VisitObjCCategoryDecl(ObjCCategoryDecl *D) {
835   VisitObjCContainerDecl(D);
836   Record.AddSourceLocation(D->getCategoryNameLoc());
837   Record.AddSourceLocation(D->getIvarLBraceLoc());
838   Record.AddSourceLocation(D->getIvarRBraceLoc());
839   Record.AddDeclRef(D->getClassInterface());
840   AddObjCTypeParamList(D->TypeParamList);
841   Record.push_back(D->protocol_size());
842   for (const auto *I : D->protocols())
843     Record.AddDeclRef(I);
844   for (const auto &PL : D->protocol_locs())
845     Record.AddSourceLocation(PL);
846   Code = serialization::DECL_OBJC_CATEGORY;
847 }
848 
849 void ASTDeclWriter::VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D) {
850   VisitNamedDecl(D);
851   Record.AddDeclRef(D->getClassInterface());
852   Code = serialization::DECL_OBJC_COMPATIBLE_ALIAS;
853 }
854 
855 void ASTDeclWriter::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
856   VisitNamedDecl(D);
857   Record.AddSourceLocation(D->getAtLoc());
858   Record.AddSourceLocation(D->getLParenLoc());
859   Record.AddTypeRef(D->getType());
860   Record.AddTypeSourceInfo(D->getTypeSourceInfo());
861   // FIXME: stable encoding
862   Record.push_back((unsigned)D->getPropertyAttributes());
863   Record.push_back((unsigned)D->getPropertyAttributesAsWritten());
864   // FIXME: stable encoding
865   Record.push_back((unsigned)D->getPropertyImplementation());
866   Record.AddDeclarationName(D->getGetterName());
867   Record.AddSourceLocation(D->getGetterNameLoc());
868   Record.AddDeclarationName(D->getSetterName());
869   Record.AddSourceLocation(D->getSetterNameLoc());
870   Record.AddDeclRef(D->getGetterMethodDecl());
871   Record.AddDeclRef(D->getSetterMethodDecl());
872   Record.AddDeclRef(D->getPropertyIvarDecl());
873   Code = serialization::DECL_OBJC_PROPERTY;
874 }
875 
876 void ASTDeclWriter::VisitObjCImplDecl(ObjCImplDecl *D) {
877   VisitObjCContainerDecl(D);
878   Record.AddDeclRef(D->getClassInterface());
879   // Abstract class (no need to define a stable serialization::DECL code).
880 }
881 
882 void ASTDeclWriter::VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D) {
883   VisitObjCImplDecl(D);
884   Record.AddSourceLocation(D->getCategoryNameLoc());
885   Code = serialization::DECL_OBJC_CATEGORY_IMPL;
886 }
887 
888 void ASTDeclWriter::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
889   VisitObjCImplDecl(D);
890   Record.AddDeclRef(D->getSuperClass());
891   Record.AddSourceLocation(D->getSuperClassLoc());
892   Record.AddSourceLocation(D->getIvarLBraceLoc());
893   Record.AddSourceLocation(D->getIvarRBraceLoc());
894   Record.push_back(D->hasNonZeroConstructors());
895   Record.push_back(D->hasDestructors());
896   Record.push_back(D->NumIvarInitializers);
897   if (D->NumIvarInitializers)
898     Record.AddCXXCtorInitializers(
899         llvm::makeArrayRef(D->init_begin(), D->init_end()));
900   Code = serialization::DECL_OBJC_IMPLEMENTATION;
901 }
902 
903 void ASTDeclWriter::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
904   VisitDecl(D);
905   Record.AddSourceLocation(D->getBeginLoc());
906   Record.AddDeclRef(D->getPropertyDecl());
907   Record.AddDeclRef(D->getPropertyIvarDecl());
908   Record.AddSourceLocation(D->getPropertyIvarDeclLoc());
909   Record.AddDeclRef(D->getGetterMethodDecl());
910   Record.AddDeclRef(D->getSetterMethodDecl());
911   Record.AddStmt(D->getGetterCXXConstructor());
912   Record.AddStmt(D->getSetterCXXAssignment());
913   Code = serialization::DECL_OBJC_PROPERTY_IMPL;
914 }
915 
916 void ASTDeclWriter::VisitFieldDecl(FieldDecl *D) {
917   VisitDeclaratorDecl(D);
918   Record.push_back(D->isMutable());
919 
920   FieldDecl::InitStorageKind ISK = D->InitStorage.getInt();
921   Record.push_back(ISK);
922   if (ISK == FieldDecl::ISK_CapturedVLAType)
923     Record.AddTypeRef(QualType(D->getCapturedVLAType(), 0));
924   else if (ISK)
925     Record.AddStmt(D->getInClassInitializer());
926 
927   Record.AddStmt(D->getBitWidth());
928 
929   if (!D->getDeclName())
930     Record.AddDeclRef(Context.getInstantiatedFromUnnamedFieldDecl(D));
931 
932   if (D->getDeclContext() == D->getLexicalDeclContext() &&
933       !D->hasAttrs() &&
934       !D->isImplicit() &&
935       !D->isUsed(false) &&
936       !D->isInvalidDecl() &&
937       !D->isReferenced() &&
938       !D->isTopLevelDeclInObjCContainer() &&
939       !D->isModulePrivate() &&
940       !D->getBitWidth() &&
941       !D->hasInClassInitializer() &&
942       !D->hasCapturedVLAType() &&
943       !D->hasExtInfo() &&
944       !ObjCIvarDecl::classofKind(D->getKind()) &&
945       !ObjCAtDefsFieldDecl::classofKind(D->getKind()) &&
946       D->getDeclName())
947     AbbrevToUse = Writer.getDeclFieldAbbrev();
948 
949   Code = serialization::DECL_FIELD;
950 }
951 
952 void ASTDeclWriter::VisitMSPropertyDecl(MSPropertyDecl *D) {
953   VisitDeclaratorDecl(D);
954   Record.AddIdentifierRef(D->getGetterId());
955   Record.AddIdentifierRef(D->getSetterId());
956   Code = serialization::DECL_MS_PROPERTY;
957 }
958 
959 void ASTDeclWriter::VisitMSGuidDecl(MSGuidDecl *D) {
960   VisitValueDecl(D);
961   MSGuidDecl::Parts Parts = D->getParts();
962   Record.push_back(Parts.Part1);
963   Record.push_back(Parts.Part2);
964   Record.push_back(Parts.Part3);
965   Record.append(std::begin(Parts.Part4And5), std::end(Parts.Part4And5));
966   Code = serialization::DECL_MS_GUID;
967 }
968 
969 void ASTDeclWriter::VisitTemplateParamObjectDecl(TemplateParamObjectDecl *D) {
970   VisitValueDecl(D);
971   Record.AddAPValue(D->getValue());
972   Code = serialization::DECL_TEMPLATE_PARAM_OBJECT;
973 }
974 
975 void ASTDeclWriter::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
976   VisitValueDecl(D);
977   Record.push_back(D->getChainingSize());
978 
979   for (const auto *P : D->chain())
980     Record.AddDeclRef(P);
981   Code = serialization::DECL_INDIRECTFIELD;
982 }
983 
984 void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
985   VisitRedeclarable(D);
986   VisitDeclaratorDecl(D);
987   Record.push_back(D->getStorageClass());
988   Record.push_back(D->getTSCSpec());
989   Record.push_back(D->getInitStyle());
990   Record.push_back(D->isARCPseudoStrong());
991   if (!isa<ParmVarDecl>(D)) {
992     Record.push_back(D->isThisDeclarationADemotedDefinition());
993     Record.push_back(D->isExceptionVariable());
994     Record.push_back(D->isNRVOVariable());
995     Record.push_back(D->isCXXForRangeDecl());
996     Record.push_back(D->isObjCForDecl());
997     Record.push_back(D->isInline());
998     Record.push_back(D->isInlineSpecified());
999     Record.push_back(D->isConstexpr());
1000     Record.push_back(D->isInitCapture());
1001     Record.push_back(D->isPreviousDeclInSameBlockScope());
1002     if (const auto *IPD = dyn_cast<ImplicitParamDecl>(D))
1003       Record.push_back(static_cast<unsigned>(IPD->getParameterKind()));
1004     else
1005       Record.push_back(0);
1006     Record.push_back(D->isEscapingByref());
1007   }
1008   Record.push_back(D->getLinkageInternal());
1009 
1010   Record.AddVarDeclInit(D);
1011 
1012   if (D->hasAttr<BlocksAttr>() && D->getType()->getAsCXXRecordDecl()) {
1013     BlockVarCopyInit Init = Writer.Context->getBlockVarCopyInit(D);
1014     Record.AddStmt(Init.getCopyExpr());
1015     if (Init.getCopyExpr())
1016       Record.push_back(Init.canThrow());
1017   }
1018 
1019   if (D->getStorageDuration() == SD_Static) {
1020     bool ModulesCodegen = false;
1021     if (Writer.WritingModule &&
1022         !D->getDescribedVarTemplate() && !D->getMemberSpecializationInfo() &&
1023         !isa<VarTemplateSpecializationDecl>(D)) {
1024       // When building a C++ Modules TS module interface unit, a strong
1025       // definition in the module interface is provided by the compilation of
1026       // that module interface unit, not by its users. (Inline variables are
1027       // still emitted in module users.)
1028       ModulesCodegen =
1029           (Writer.WritingModule->Kind == Module::ModuleInterfaceUnit ||
1030            (D->hasAttr<DLLExportAttr>() &&
1031             Writer.Context->getLangOpts().BuildingPCHWithObjectFile)) &&
1032           Writer.Context->GetGVALinkageForVariable(D) == GVA_StrongExternal;
1033     }
1034     Record.push_back(ModulesCodegen);
1035     if (ModulesCodegen)
1036       Writer.ModularCodegenDecls.push_back(Writer.GetDeclRef(D));
1037   }
1038 
1039   enum {
1040     VarNotTemplate = 0, VarTemplate, StaticDataMemberSpecialization
1041   };
1042   if (VarTemplateDecl *TemplD = D->getDescribedVarTemplate()) {
1043     Record.push_back(VarTemplate);
1044     Record.AddDeclRef(TemplD);
1045   } else if (MemberSpecializationInfo *SpecInfo
1046                = D->getMemberSpecializationInfo()) {
1047     Record.push_back(StaticDataMemberSpecialization);
1048     Record.AddDeclRef(SpecInfo->getInstantiatedFrom());
1049     Record.push_back(SpecInfo->getTemplateSpecializationKind());
1050     Record.AddSourceLocation(SpecInfo->getPointOfInstantiation());
1051   } else {
1052     Record.push_back(VarNotTemplate);
1053   }
1054 
1055   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1056       !D->hasAttrs() &&
1057       !D->isImplicit() &&
1058       !D->isUsed(false) &&
1059       !D->isInvalidDecl() &&
1060       !D->isReferenced() &&
1061       !D->isTopLevelDeclInObjCContainer() &&
1062       D->getAccess() == AS_none &&
1063       !D->isModulePrivate() &&
1064       !needsAnonymousDeclarationNumber(D) &&
1065       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1066       !D->hasExtInfo() &&
1067       D->getFirstDecl() == D->getMostRecentDecl() &&
1068       D->getKind() == Decl::Var &&
1069       !D->isInline() &&
1070       !D->isConstexpr() &&
1071       !D->isInitCapture() &&
1072       !D->isPreviousDeclInSameBlockScope() &&
1073       !(D->hasAttr<BlocksAttr>() && D->getType()->getAsCXXRecordDecl()) &&
1074       !D->isEscapingByref() &&
1075       D->getStorageDuration() != SD_Static &&
1076       !D->getMemberSpecializationInfo())
1077     AbbrevToUse = Writer.getDeclVarAbbrev();
1078 
1079   Code = serialization::DECL_VAR;
1080 }
1081 
1082 void ASTDeclWriter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
1083   VisitVarDecl(D);
1084   Code = serialization::DECL_IMPLICIT_PARAM;
1085 }
1086 
1087 void ASTDeclWriter::VisitParmVarDecl(ParmVarDecl *D) {
1088   VisitVarDecl(D);
1089   Record.push_back(D->isObjCMethodParameter());
1090   Record.push_back(D->getFunctionScopeDepth());
1091   Record.push_back(D->getFunctionScopeIndex());
1092   Record.push_back(D->getObjCDeclQualifier()); // FIXME: stable encoding
1093   Record.push_back(D->isKNRPromoted());
1094   Record.push_back(D->hasInheritedDefaultArg());
1095   Record.push_back(D->hasUninstantiatedDefaultArg());
1096   if (D->hasUninstantiatedDefaultArg())
1097     Record.AddStmt(D->getUninstantiatedDefaultArg());
1098   Code = serialization::DECL_PARM_VAR;
1099 
1100   // If the assumptions about the DECL_PARM_VAR abbrev are true, use it.  Here
1101   // we dynamically check for the properties that we optimize for, but don't
1102   // know are true of all PARM_VAR_DECLs.
1103   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1104       !D->hasAttrs() &&
1105       !D->hasExtInfo() &&
1106       !D->isImplicit() &&
1107       !D->isUsed(false) &&
1108       !D->isInvalidDecl() &&
1109       !D->isReferenced() &&
1110       D->getAccess() == AS_none &&
1111       !D->isModulePrivate() &&
1112       D->getStorageClass() == 0 &&
1113       D->getInitStyle() == VarDecl::CInit && // Can params have anything else?
1114       D->getFunctionScopeDepth() == 0 &&
1115       D->getObjCDeclQualifier() == 0 &&
1116       !D->isKNRPromoted() &&
1117       !D->hasInheritedDefaultArg() &&
1118       D->getInit() == nullptr &&
1119       !D->hasUninstantiatedDefaultArg())  // No default expr.
1120     AbbrevToUse = Writer.getDeclParmVarAbbrev();
1121 
1122   // Check things we know are true of *every* PARM_VAR_DECL, which is more than
1123   // just us assuming it.
1124   assert(!D->getTSCSpec() && "PARM_VAR_DECL can't use TLS");
1125   assert(!D->isThisDeclarationADemotedDefinition()
1126          && "PARM_VAR_DECL can't be demoted definition.");
1127   assert(D->getAccess() == AS_none && "PARM_VAR_DECL can't be public/private");
1128   assert(!D->isExceptionVariable() && "PARM_VAR_DECL can't be exception var");
1129   assert(D->getPreviousDecl() == nullptr && "PARM_VAR_DECL can't be redecl");
1130   assert(!D->isStaticDataMember() &&
1131          "PARM_VAR_DECL can't be static data member");
1132 }
1133 
1134 void ASTDeclWriter::VisitDecompositionDecl(DecompositionDecl *D) {
1135   // Record the number of bindings first to simplify deserialization.
1136   Record.push_back(D->bindings().size());
1137 
1138   VisitVarDecl(D);
1139   for (auto *B : D->bindings())
1140     Record.AddDeclRef(B);
1141   Code = serialization::DECL_DECOMPOSITION;
1142 }
1143 
1144 void ASTDeclWriter::VisitBindingDecl(BindingDecl *D) {
1145   VisitValueDecl(D);
1146   Record.AddStmt(D->getBinding());
1147   Code = serialization::DECL_BINDING;
1148 }
1149 
1150 void ASTDeclWriter::VisitFileScopeAsmDecl(FileScopeAsmDecl *D) {
1151   VisitDecl(D);
1152   Record.AddStmt(D->getAsmString());
1153   Record.AddSourceLocation(D->getRParenLoc());
1154   Code = serialization::DECL_FILE_SCOPE_ASM;
1155 }
1156 
1157 void ASTDeclWriter::VisitEmptyDecl(EmptyDecl *D) {
1158   VisitDecl(D);
1159   Code = serialization::DECL_EMPTY;
1160 }
1161 
1162 void ASTDeclWriter::VisitLifetimeExtendedTemporaryDecl(
1163     LifetimeExtendedTemporaryDecl *D) {
1164   VisitDecl(D);
1165   Record.AddDeclRef(D->getExtendingDecl());
1166   Record.AddStmt(D->getTemporaryExpr());
1167   Record.push_back(static_cast<bool>(D->getValue()));
1168   if (D->getValue())
1169     Record.AddAPValue(*D->getValue());
1170   Record.push_back(D->getManglingNumber());
1171   Code = serialization::DECL_LIFETIME_EXTENDED_TEMPORARY;
1172 }
1173 void ASTDeclWriter::VisitBlockDecl(BlockDecl *D) {
1174   VisitDecl(D);
1175   Record.AddStmt(D->getBody());
1176   Record.AddTypeSourceInfo(D->getSignatureAsWritten());
1177   Record.push_back(D->param_size());
1178   for (ParmVarDecl *P : D->parameters())
1179     Record.AddDeclRef(P);
1180   Record.push_back(D->isVariadic());
1181   Record.push_back(D->blockMissingReturnType());
1182   Record.push_back(D->isConversionFromLambda());
1183   Record.push_back(D->doesNotEscape());
1184   Record.push_back(D->canAvoidCopyToHeap());
1185   Record.push_back(D->capturesCXXThis());
1186   Record.push_back(D->getNumCaptures());
1187   for (const auto &capture : D->captures()) {
1188     Record.AddDeclRef(capture.getVariable());
1189 
1190     unsigned flags = 0;
1191     if (capture.isByRef()) flags |= 1;
1192     if (capture.isNested()) flags |= 2;
1193     if (capture.hasCopyExpr()) flags |= 4;
1194     Record.push_back(flags);
1195 
1196     if (capture.hasCopyExpr()) Record.AddStmt(capture.getCopyExpr());
1197   }
1198 
1199   Code = serialization::DECL_BLOCK;
1200 }
1201 
1202 void ASTDeclWriter::VisitCapturedDecl(CapturedDecl *CD) {
1203   Record.push_back(CD->getNumParams());
1204   VisitDecl(CD);
1205   Record.push_back(CD->getContextParamPosition());
1206   Record.push_back(CD->isNothrow() ? 1 : 0);
1207   // Body is stored by VisitCapturedStmt.
1208   for (unsigned I = 0; I < CD->getNumParams(); ++I)
1209     Record.AddDeclRef(CD->getParam(I));
1210   Code = serialization::DECL_CAPTURED;
1211 }
1212 
1213 void ASTDeclWriter::VisitLinkageSpecDecl(LinkageSpecDecl *D) {
1214   VisitDecl(D);
1215   Record.push_back(D->getLanguage());
1216   Record.AddSourceLocation(D->getExternLoc());
1217   Record.AddSourceLocation(D->getRBraceLoc());
1218   Code = serialization::DECL_LINKAGE_SPEC;
1219 }
1220 
1221 void ASTDeclWriter::VisitExportDecl(ExportDecl *D) {
1222   VisitDecl(D);
1223   Record.AddSourceLocation(D->getRBraceLoc());
1224   Code = serialization::DECL_EXPORT;
1225 }
1226 
1227 void ASTDeclWriter::VisitLabelDecl(LabelDecl *D) {
1228   VisitNamedDecl(D);
1229   Record.AddSourceLocation(D->getBeginLoc());
1230   Code = serialization::DECL_LABEL;
1231 }
1232 
1233 
1234 void ASTDeclWriter::VisitNamespaceDecl(NamespaceDecl *D) {
1235   VisitRedeclarable(D);
1236   VisitNamedDecl(D);
1237   Record.push_back(D->isInline());
1238   Record.AddSourceLocation(D->getBeginLoc());
1239   Record.AddSourceLocation(D->getRBraceLoc());
1240 
1241   if (D->isOriginalNamespace())
1242     Record.AddDeclRef(D->getAnonymousNamespace());
1243   Code = serialization::DECL_NAMESPACE;
1244 
1245   if (Writer.hasChain() && D->isAnonymousNamespace() &&
1246       D == D->getMostRecentDecl()) {
1247     // This is a most recent reopening of the anonymous namespace. If its parent
1248     // is in a previous PCH (or is the TU), mark that parent for update, because
1249     // the original namespace always points to the latest re-opening of its
1250     // anonymous namespace.
1251     Decl *Parent = cast<Decl>(
1252         D->getParent()->getRedeclContext()->getPrimaryContext());
1253     if (Parent->isFromASTFile() || isa<TranslationUnitDecl>(Parent)) {
1254       Writer.DeclUpdates[Parent].push_back(
1255           ASTWriter::DeclUpdate(UPD_CXX_ADDED_ANONYMOUS_NAMESPACE, D));
1256     }
1257   }
1258 }
1259 
1260 void ASTDeclWriter::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
1261   VisitRedeclarable(D);
1262   VisitNamedDecl(D);
1263   Record.AddSourceLocation(D->getNamespaceLoc());
1264   Record.AddSourceLocation(D->getTargetNameLoc());
1265   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1266   Record.AddDeclRef(D->getNamespace());
1267   Code = serialization::DECL_NAMESPACE_ALIAS;
1268 }
1269 
1270 void ASTDeclWriter::VisitUsingDecl(UsingDecl *D) {
1271   VisitNamedDecl(D);
1272   Record.AddSourceLocation(D->getUsingLoc());
1273   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1274   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
1275   Record.AddDeclRef(D->FirstUsingShadow.getPointer());
1276   Record.push_back(D->hasTypename());
1277   Record.AddDeclRef(Context.getInstantiatedFromUsingDecl(D));
1278   Code = serialization::DECL_USING;
1279 }
1280 
1281 void ASTDeclWriter::VisitUsingEnumDecl(UsingEnumDecl *D) {
1282   VisitNamedDecl(D);
1283   Record.AddSourceLocation(D->getUsingLoc());
1284   Record.AddSourceLocation(D->getEnumLoc());
1285   Record.AddDeclRef(D->getEnumDecl());
1286   Record.AddDeclRef(D->FirstUsingShadow.getPointer());
1287   Record.AddDeclRef(Context.getInstantiatedFromUsingEnumDecl(D));
1288   Code = serialization::DECL_USING_ENUM;
1289 }
1290 
1291 void ASTDeclWriter::VisitUsingPackDecl(UsingPackDecl *D) {
1292   Record.push_back(D->NumExpansions);
1293   VisitNamedDecl(D);
1294   Record.AddDeclRef(D->getInstantiatedFromUsingDecl());
1295   for (auto *E : D->expansions())
1296     Record.AddDeclRef(E);
1297   Code = serialization::DECL_USING_PACK;
1298 }
1299 
1300 void ASTDeclWriter::VisitUsingShadowDecl(UsingShadowDecl *D) {
1301   VisitRedeclarable(D);
1302   VisitNamedDecl(D);
1303   Record.AddDeclRef(D->getTargetDecl());
1304   Record.push_back(D->getIdentifierNamespace());
1305   Record.AddDeclRef(D->UsingOrNextShadow);
1306   Record.AddDeclRef(Context.getInstantiatedFromUsingShadowDecl(D));
1307   Code = serialization::DECL_USING_SHADOW;
1308 }
1309 
1310 void ASTDeclWriter::VisitConstructorUsingShadowDecl(
1311     ConstructorUsingShadowDecl *D) {
1312   VisitUsingShadowDecl(D);
1313   Record.AddDeclRef(D->NominatedBaseClassShadowDecl);
1314   Record.AddDeclRef(D->ConstructedBaseClassShadowDecl);
1315   Record.push_back(D->IsVirtual);
1316   Code = serialization::DECL_CONSTRUCTOR_USING_SHADOW;
1317 }
1318 
1319 void ASTDeclWriter::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1320   VisitNamedDecl(D);
1321   Record.AddSourceLocation(D->getUsingLoc());
1322   Record.AddSourceLocation(D->getNamespaceKeyLocation());
1323   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1324   Record.AddDeclRef(D->getNominatedNamespace());
1325   Record.AddDeclRef(dyn_cast<Decl>(D->getCommonAncestor()));
1326   Code = serialization::DECL_USING_DIRECTIVE;
1327 }
1328 
1329 void ASTDeclWriter::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1330   VisitValueDecl(D);
1331   Record.AddSourceLocation(D->getUsingLoc());
1332   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1333   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
1334   Record.AddSourceLocation(D->getEllipsisLoc());
1335   Code = serialization::DECL_UNRESOLVED_USING_VALUE;
1336 }
1337 
1338 void ASTDeclWriter::VisitUnresolvedUsingTypenameDecl(
1339                                                UnresolvedUsingTypenameDecl *D) {
1340   VisitTypeDecl(D);
1341   Record.AddSourceLocation(D->getTypenameLoc());
1342   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1343   Record.AddSourceLocation(D->getEllipsisLoc());
1344   Code = serialization::DECL_UNRESOLVED_USING_TYPENAME;
1345 }
1346 
1347 void ASTDeclWriter::VisitUnresolvedUsingIfExistsDecl(
1348     UnresolvedUsingIfExistsDecl *D) {
1349   VisitNamedDecl(D);
1350   Code = serialization::DECL_UNRESOLVED_USING_IF_EXISTS;
1351 }
1352 
1353 void ASTDeclWriter::VisitCXXRecordDecl(CXXRecordDecl *D) {
1354   VisitRecordDecl(D);
1355 
1356   enum {
1357     CXXRecNotTemplate = 0, CXXRecTemplate, CXXRecMemberSpecialization
1358   };
1359   if (ClassTemplateDecl *TemplD = D->getDescribedClassTemplate()) {
1360     Record.push_back(CXXRecTemplate);
1361     Record.AddDeclRef(TemplD);
1362   } else if (MemberSpecializationInfo *MSInfo
1363                = D->getMemberSpecializationInfo()) {
1364     Record.push_back(CXXRecMemberSpecialization);
1365     Record.AddDeclRef(MSInfo->getInstantiatedFrom());
1366     Record.push_back(MSInfo->getTemplateSpecializationKind());
1367     Record.AddSourceLocation(MSInfo->getPointOfInstantiation());
1368   } else {
1369     Record.push_back(CXXRecNotTemplate);
1370   }
1371 
1372   Record.push_back(D->isThisDeclarationADefinition());
1373   if (D->isThisDeclarationADefinition())
1374     Record.AddCXXDefinitionData(D);
1375 
1376   // Store (what we currently believe to be) the key function to avoid
1377   // deserializing every method so we can compute it.
1378   if (D->isCompleteDefinition())
1379     Record.AddDeclRef(Context.getCurrentKeyFunction(D));
1380 
1381   Code = serialization::DECL_CXX_RECORD;
1382 }
1383 
1384 void ASTDeclWriter::VisitCXXMethodDecl(CXXMethodDecl *D) {
1385   VisitFunctionDecl(D);
1386   if (D->isCanonicalDecl()) {
1387     Record.push_back(D->size_overridden_methods());
1388     for (const CXXMethodDecl *MD : D->overridden_methods())
1389       Record.AddDeclRef(MD);
1390   } else {
1391     // We only need to record overridden methods once for the canonical decl.
1392     Record.push_back(0);
1393   }
1394 
1395   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1396       D->getFirstDecl() == D->getMostRecentDecl() &&
1397       !D->isInvalidDecl() &&
1398       !D->hasAttrs() &&
1399       !D->isTopLevelDeclInObjCContainer() &&
1400       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1401       !D->hasExtInfo() &&
1402       !D->hasInheritedPrototype() &&
1403       D->hasWrittenPrototype())
1404     AbbrevToUse = Writer.getDeclCXXMethodAbbrev();
1405 
1406   Code = serialization::DECL_CXX_METHOD;
1407 }
1408 
1409 void ASTDeclWriter::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1410   Record.push_back(D->getTrailingAllocKind());
1411   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
1412   if (auto Inherited = D->getInheritedConstructor()) {
1413     Record.AddDeclRef(Inherited.getShadowDecl());
1414     Record.AddDeclRef(Inherited.getConstructor());
1415   }
1416 
1417   VisitCXXMethodDecl(D);
1418   Code = serialization::DECL_CXX_CONSTRUCTOR;
1419 }
1420 
1421 void ASTDeclWriter::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1422   VisitCXXMethodDecl(D);
1423 
1424   Record.AddDeclRef(D->getOperatorDelete());
1425   if (D->getOperatorDelete())
1426     Record.AddStmt(D->getOperatorDeleteThisArg());
1427 
1428   Code = serialization::DECL_CXX_DESTRUCTOR;
1429 }
1430 
1431 void ASTDeclWriter::VisitCXXConversionDecl(CXXConversionDecl *D) {
1432   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
1433   VisitCXXMethodDecl(D);
1434   Code = serialization::DECL_CXX_CONVERSION;
1435 }
1436 
1437 void ASTDeclWriter::VisitImportDecl(ImportDecl *D) {
1438   VisitDecl(D);
1439   Record.push_back(Writer.getSubmoduleID(D->getImportedModule()));
1440   ArrayRef<SourceLocation> IdentifierLocs = D->getIdentifierLocs();
1441   Record.push_back(!IdentifierLocs.empty());
1442   if (IdentifierLocs.empty()) {
1443     Record.AddSourceLocation(D->getEndLoc());
1444     Record.push_back(1);
1445   } else {
1446     for (unsigned I = 0, N = IdentifierLocs.size(); I != N; ++I)
1447       Record.AddSourceLocation(IdentifierLocs[I]);
1448     Record.push_back(IdentifierLocs.size());
1449   }
1450   // Note: the number of source locations must always be the last element in
1451   // the record.
1452   Code = serialization::DECL_IMPORT;
1453 }
1454 
1455 void ASTDeclWriter::VisitAccessSpecDecl(AccessSpecDecl *D) {
1456   VisitDecl(D);
1457   Record.AddSourceLocation(D->getColonLoc());
1458   Code = serialization::DECL_ACCESS_SPEC;
1459 }
1460 
1461 void ASTDeclWriter::VisitFriendDecl(FriendDecl *D) {
1462   // Record the number of friend type template parameter lists here
1463   // so as to simplify memory allocation during deserialization.
1464   Record.push_back(D->NumTPLists);
1465   VisitDecl(D);
1466   bool hasFriendDecl = D->Friend.is<NamedDecl*>();
1467   Record.push_back(hasFriendDecl);
1468   if (hasFriendDecl)
1469     Record.AddDeclRef(D->getFriendDecl());
1470   else
1471     Record.AddTypeSourceInfo(D->getFriendType());
1472   for (unsigned i = 0; i < D->NumTPLists; ++i)
1473     Record.AddTemplateParameterList(D->getFriendTypeTemplateParameterList(i));
1474   Record.AddDeclRef(D->getNextFriend());
1475   Record.push_back(D->UnsupportedFriend);
1476   Record.AddSourceLocation(D->FriendLoc);
1477   Code = serialization::DECL_FRIEND;
1478 }
1479 
1480 void ASTDeclWriter::VisitFriendTemplateDecl(FriendTemplateDecl *D) {
1481   VisitDecl(D);
1482   Record.push_back(D->getNumTemplateParameters());
1483   for (unsigned i = 0, e = D->getNumTemplateParameters(); i != e; ++i)
1484     Record.AddTemplateParameterList(D->getTemplateParameterList(i));
1485   Record.push_back(D->getFriendDecl() != nullptr);
1486   if (D->getFriendDecl())
1487     Record.AddDeclRef(D->getFriendDecl());
1488   else
1489     Record.AddTypeSourceInfo(D->getFriendType());
1490   Record.AddSourceLocation(D->getFriendLoc());
1491   Code = serialization::DECL_FRIEND_TEMPLATE;
1492 }
1493 
1494 void ASTDeclWriter::VisitTemplateDecl(TemplateDecl *D) {
1495   VisitNamedDecl(D);
1496 
1497   Record.AddDeclRef(D->getTemplatedDecl());
1498   Record.AddTemplateParameterList(D->getTemplateParameters());
1499 }
1500 
1501 void ASTDeclWriter::VisitConceptDecl(ConceptDecl *D) {
1502   VisitTemplateDecl(D);
1503   Record.AddStmt(D->getConstraintExpr());
1504   Code = serialization::DECL_CONCEPT;
1505 }
1506 
1507 void ASTDeclWriter::VisitRequiresExprBodyDecl(RequiresExprBodyDecl *D) {
1508   Code = serialization::DECL_REQUIRES_EXPR_BODY;
1509 }
1510 
1511 void ASTDeclWriter::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
1512   VisitRedeclarable(D);
1513 
1514   // Emit data to initialize CommonOrPrev before VisitTemplateDecl so that
1515   // getCommonPtr() can be used while this is still initializing.
1516   if (D->isFirstDecl()) {
1517     // This declaration owns the 'common' pointer, so serialize that data now.
1518     Record.AddDeclRef(D->getInstantiatedFromMemberTemplate());
1519     if (D->getInstantiatedFromMemberTemplate())
1520       Record.push_back(D->isMemberSpecialization());
1521   }
1522 
1523   VisitTemplateDecl(D);
1524   Record.push_back(D->getIdentifierNamespace());
1525 }
1526 
1527 void ASTDeclWriter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
1528   VisitRedeclarableTemplateDecl(D);
1529 
1530   if (D->isFirstDecl())
1531     AddTemplateSpecializations(D);
1532   Code = serialization::DECL_CLASS_TEMPLATE;
1533 }
1534 
1535 void ASTDeclWriter::VisitClassTemplateSpecializationDecl(
1536                                            ClassTemplateSpecializationDecl *D) {
1537   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1538 
1539   VisitCXXRecordDecl(D);
1540 
1541   llvm::PointerUnion<ClassTemplateDecl *,
1542                      ClassTemplatePartialSpecializationDecl *> InstFrom
1543     = D->getSpecializedTemplateOrPartial();
1544   if (Decl *InstFromD = InstFrom.dyn_cast<ClassTemplateDecl *>()) {
1545     Record.AddDeclRef(InstFromD);
1546   } else {
1547     Record.AddDeclRef(InstFrom.get<ClassTemplatePartialSpecializationDecl *>());
1548     Record.AddTemplateArgumentList(&D->getTemplateInstantiationArgs());
1549   }
1550 
1551   Record.AddTemplateArgumentList(&D->getTemplateArgs());
1552   Record.AddSourceLocation(D->getPointOfInstantiation());
1553   Record.push_back(D->getSpecializationKind());
1554   Record.push_back(D->isCanonicalDecl());
1555 
1556   if (D->isCanonicalDecl()) {
1557     // When reading, we'll add it to the folding set of the following template.
1558     Record.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl());
1559   }
1560 
1561   // Explicit info.
1562   Record.AddTypeSourceInfo(D->getTypeAsWritten());
1563   if (D->getTypeAsWritten()) {
1564     Record.AddSourceLocation(D->getExternLoc());
1565     Record.AddSourceLocation(D->getTemplateKeywordLoc());
1566   }
1567 
1568   Code = serialization::DECL_CLASS_TEMPLATE_SPECIALIZATION;
1569 }
1570 
1571 void ASTDeclWriter::VisitClassTemplatePartialSpecializationDecl(
1572                                     ClassTemplatePartialSpecializationDecl *D) {
1573   Record.AddTemplateParameterList(D->getTemplateParameters());
1574   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1575 
1576   VisitClassTemplateSpecializationDecl(D);
1577 
1578   // These are read/set from/to the first declaration.
1579   if (D->getPreviousDecl() == nullptr) {
1580     Record.AddDeclRef(D->getInstantiatedFromMember());
1581     Record.push_back(D->isMemberSpecialization());
1582   }
1583 
1584   Code = serialization::DECL_CLASS_TEMPLATE_PARTIAL_SPECIALIZATION;
1585 }
1586 
1587 void ASTDeclWriter::VisitVarTemplateDecl(VarTemplateDecl *D) {
1588   VisitRedeclarableTemplateDecl(D);
1589 
1590   if (D->isFirstDecl())
1591     AddTemplateSpecializations(D);
1592   Code = serialization::DECL_VAR_TEMPLATE;
1593 }
1594 
1595 void ASTDeclWriter::VisitVarTemplateSpecializationDecl(
1596     VarTemplateSpecializationDecl *D) {
1597   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1598 
1599   VisitVarDecl(D);
1600 
1601   llvm::PointerUnion<VarTemplateDecl *, VarTemplatePartialSpecializationDecl *>
1602   InstFrom = D->getSpecializedTemplateOrPartial();
1603   if (Decl *InstFromD = InstFrom.dyn_cast<VarTemplateDecl *>()) {
1604     Record.AddDeclRef(InstFromD);
1605   } else {
1606     Record.AddDeclRef(InstFrom.get<VarTemplatePartialSpecializationDecl *>());
1607     Record.AddTemplateArgumentList(&D->getTemplateInstantiationArgs());
1608   }
1609 
1610   // Explicit info.
1611   Record.AddTypeSourceInfo(D->getTypeAsWritten());
1612   if (D->getTypeAsWritten()) {
1613     Record.AddSourceLocation(D->getExternLoc());
1614     Record.AddSourceLocation(D->getTemplateKeywordLoc());
1615   }
1616 
1617   Record.AddTemplateArgumentList(&D->getTemplateArgs());
1618   Record.AddSourceLocation(D->getPointOfInstantiation());
1619   Record.push_back(D->getSpecializationKind());
1620   Record.push_back(D->IsCompleteDefinition);
1621   Record.push_back(D->isCanonicalDecl());
1622 
1623   if (D->isCanonicalDecl()) {
1624     // When reading, we'll add it to the folding set of the following template.
1625     Record.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl());
1626   }
1627 
1628   Code = serialization::DECL_VAR_TEMPLATE_SPECIALIZATION;
1629 }
1630 
1631 void ASTDeclWriter::VisitVarTemplatePartialSpecializationDecl(
1632     VarTemplatePartialSpecializationDecl *D) {
1633   Record.AddTemplateParameterList(D->getTemplateParameters());
1634   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1635 
1636   VisitVarTemplateSpecializationDecl(D);
1637 
1638   // These are read/set from/to the first declaration.
1639   if (D->getPreviousDecl() == nullptr) {
1640     Record.AddDeclRef(D->getInstantiatedFromMember());
1641     Record.push_back(D->isMemberSpecialization());
1642   }
1643 
1644   Code = serialization::DECL_VAR_TEMPLATE_PARTIAL_SPECIALIZATION;
1645 }
1646 
1647 void ASTDeclWriter::VisitClassScopeFunctionSpecializationDecl(
1648                                     ClassScopeFunctionSpecializationDecl *D) {
1649   VisitDecl(D);
1650   Record.AddDeclRef(D->getSpecialization());
1651   Record.push_back(D->hasExplicitTemplateArgs());
1652   if (D->hasExplicitTemplateArgs())
1653     Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1654   Code = serialization::DECL_CLASS_SCOPE_FUNCTION_SPECIALIZATION;
1655 }
1656 
1657 
1658 void ASTDeclWriter::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
1659   VisitRedeclarableTemplateDecl(D);
1660 
1661   if (D->isFirstDecl())
1662     AddTemplateSpecializations(D);
1663   Code = serialization::DECL_FUNCTION_TEMPLATE;
1664 }
1665 
1666 void ASTDeclWriter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
1667   Record.push_back(D->hasTypeConstraint());
1668   VisitTypeDecl(D);
1669 
1670   Record.push_back(D->wasDeclaredWithTypename());
1671 
1672   const TypeConstraint *TC = D->getTypeConstraint();
1673   Record.push_back(TC != nullptr);
1674   if (TC) {
1675     Record.AddNestedNameSpecifierLoc(TC->getNestedNameSpecifierLoc());
1676     Record.AddDeclarationNameInfo(TC->getConceptNameInfo());
1677     Record.AddDeclRef(TC->getNamedConcept());
1678     Record.push_back(TC->getTemplateArgsAsWritten() != nullptr);
1679     if (TC->getTemplateArgsAsWritten())
1680       Record.AddASTTemplateArgumentListInfo(TC->getTemplateArgsAsWritten());
1681     Record.AddStmt(TC->getImmediatelyDeclaredConstraint());
1682     Record.push_back(D->isExpandedParameterPack());
1683     if (D->isExpandedParameterPack())
1684       Record.push_back(D->getNumExpansionParameters());
1685   }
1686 
1687   bool OwnsDefaultArg = D->hasDefaultArgument() &&
1688                         !D->defaultArgumentWasInherited();
1689   Record.push_back(OwnsDefaultArg);
1690   if (OwnsDefaultArg)
1691     Record.AddTypeSourceInfo(D->getDefaultArgumentInfo());
1692 
1693   Code = serialization::DECL_TEMPLATE_TYPE_PARM;
1694 }
1695 
1696 void ASTDeclWriter::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
1697   // For an expanded parameter pack, record the number of expansion types here
1698   // so that it's easier for deserialization to allocate the right amount of
1699   // memory.
1700   Expr *TypeConstraint = D->getPlaceholderTypeConstraint();
1701   Record.push_back(!!TypeConstraint);
1702   if (D->isExpandedParameterPack())
1703     Record.push_back(D->getNumExpansionTypes());
1704 
1705   VisitDeclaratorDecl(D);
1706   // TemplateParmPosition.
1707   Record.push_back(D->getDepth());
1708   Record.push_back(D->getPosition());
1709   if (TypeConstraint)
1710     Record.AddStmt(TypeConstraint);
1711 
1712   if (D->isExpandedParameterPack()) {
1713     for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1714       Record.AddTypeRef(D->getExpansionType(I));
1715       Record.AddTypeSourceInfo(D->getExpansionTypeSourceInfo(I));
1716     }
1717 
1718     Code = serialization::DECL_EXPANDED_NON_TYPE_TEMPLATE_PARM_PACK;
1719   } else {
1720     // Rest of NonTypeTemplateParmDecl.
1721     Record.push_back(D->isParameterPack());
1722     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1723                           !D->defaultArgumentWasInherited();
1724     Record.push_back(OwnsDefaultArg);
1725     if (OwnsDefaultArg)
1726       Record.AddStmt(D->getDefaultArgument());
1727     Code = serialization::DECL_NON_TYPE_TEMPLATE_PARM;
1728   }
1729 }
1730 
1731 void ASTDeclWriter::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
1732   // For an expanded parameter pack, record the number of expansion types here
1733   // so that it's easier for deserialization to allocate the right amount of
1734   // memory.
1735   if (D->isExpandedParameterPack())
1736     Record.push_back(D->getNumExpansionTemplateParameters());
1737 
1738   VisitTemplateDecl(D);
1739   // TemplateParmPosition.
1740   Record.push_back(D->getDepth());
1741   Record.push_back(D->getPosition());
1742 
1743   if (D->isExpandedParameterPack()) {
1744     for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
1745          I != N; ++I)
1746       Record.AddTemplateParameterList(D->getExpansionTemplateParameters(I));
1747     Code = serialization::DECL_EXPANDED_TEMPLATE_TEMPLATE_PARM_PACK;
1748   } else {
1749     // Rest of TemplateTemplateParmDecl.
1750     Record.push_back(D->isParameterPack());
1751     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1752                           !D->defaultArgumentWasInherited();
1753     Record.push_back(OwnsDefaultArg);
1754     if (OwnsDefaultArg)
1755       Record.AddTemplateArgumentLoc(D->getDefaultArgument());
1756     Code = serialization::DECL_TEMPLATE_TEMPLATE_PARM;
1757   }
1758 }
1759 
1760 void ASTDeclWriter::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
1761   VisitRedeclarableTemplateDecl(D);
1762   Code = serialization::DECL_TYPE_ALIAS_TEMPLATE;
1763 }
1764 
1765 void ASTDeclWriter::VisitStaticAssertDecl(StaticAssertDecl *D) {
1766   VisitDecl(D);
1767   Record.AddStmt(D->getAssertExpr());
1768   Record.push_back(D->isFailed());
1769   Record.AddStmt(D->getMessage());
1770   Record.AddSourceLocation(D->getRParenLoc());
1771   Code = serialization::DECL_STATIC_ASSERT;
1772 }
1773 
1774 /// Emit the DeclContext part of a declaration context decl.
1775 void ASTDeclWriter::VisitDeclContext(DeclContext *DC) {
1776   Record.AddOffset(Writer.WriteDeclContextLexicalBlock(Context, DC));
1777   Record.AddOffset(Writer.WriteDeclContextVisibleBlock(Context, DC));
1778 }
1779 
1780 const Decl *ASTWriter::getFirstLocalDecl(const Decl *D) {
1781   assert(IsLocalDecl(D) && "expected a local declaration");
1782 
1783   const Decl *Canon = D->getCanonicalDecl();
1784   if (IsLocalDecl(Canon))
1785     return Canon;
1786 
1787   const Decl *&CacheEntry = FirstLocalDeclCache[Canon];
1788   if (CacheEntry)
1789     return CacheEntry;
1790 
1791   for (const Decl *Redecl = D; Redecl; Redecl = Redecl->getPreviousDecl())
1792     if (IsLocalDecl(Redecl))
1793       D = Redecl;
1794   return CacheEntry = D;
1795 }
1796 
1797 template <typename T>
1798 void ASTDeclWriter::VisitRedeclarable(Redeclarable<T> *D) {
1799   T *First = D->getFirstDecl();
1800   T *MostRecent = First->getMostRecentDecl();
1801   T *DAsT = static_cast<T *>(D);
1802   if (MostRecent != First) {
1803     assert(isRedeclarableDeclKind(DAsT->getKind()) &&
1804            "Not considered redeclarable?");
1805 
1806     Record.AddDeclRef(First);
1807 
1808     // Write out a list of local redeclarations of this declaration if it's the
1809     // first local declaration in the chain.
1810     const Decl *FirstLocal = Writer.getFirstLocalDecl(DAsT);
1811     if (DAsT == FirstLocal) {
1812       // Emit a list of all imported first declarations so that we can be sure
1813       // that all redeclarations visible to this module are before D in the
1814       // redecl chain.
1815       unsigned I = Record.size();
1816       Record.push_back(0);
1817       if (Writer.Chain)
1818         AddFirstDeclFromEachModule(DAsT, /*IncludeLocal*/false);
1819       // This is the number of imported first declarations + 1.
1820       Record[I] = Record.size() - I;
1821 
1822       // Collect the set of local redeclarations of this declaration, from
1823       // newest to oldest.
1824       ASTWriter::RecordData LocalRedecls;
1825       ASTRecordWriter LocalRedeclWriter(Record, LocalRedecls);
1826       for (const Decl *Prev = FirstLocal->getMostRecentDecl();
1827            Prev != FirstLocal; Prev = Prev->getPreviousDecl())
1828         if (!Prev->isFromASTFile())
1829           LocalRedeclWriter.AddDeclRef(Prev);
1830 
1831       // If we have any redecls, write them now as a separate record preceding
1832       // the declaration itself.
1833       if (LocalRedecls.empty())
1834         Record.push_back(0);
1835       else
1836         Record.AddOffset(LocalRedeclWriter.Emit(LOCAL_REDECLARATIONS));
1837     } else {
1838       Record.push_back(0);
1839       Record.AddDeclRef(FirstLocal);
1840     }
1841 
1842     // Make sure that we serialize both the previous and the most-recent
1843     // declarations, which (transitively) ensures that all declarations in the
1844     // chain get serialized.
1845     //
1846     // FIXME: This is not correct; when we reach an imported declaration we
1847     // won't emit its previous declaration.
1848     (void)Writer.GetDeclRef(D->getPreviousDecl());
1849     (void)Writer.GetDeclRef(MostRecent);
1850   } else {
1851     // We use the sentinel value 0 to indicate an only declaration.
1852     Record.push_back(0);
1853   }
1854 }
1855 
1856 void ASTDeclWriter::VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D) {
1857   Record.writeOMPChildren(D->Data);
1858   VisitDecl(D);
1859   Code = serialization::DECL_OMP_THREADPRIVATE;
1860 }
1861 
1862 void ASTDeclWriter::VisitOMPAllocateDecl(OMPAllocateDecl *D) {
1863   Record.writeOMPChildren(D->Data);
1864   VisitDecl(D);
1865   Code = serialization::DECL_OMP_ALLOCATE;
1866 }
1867 
1868 void ASTDeclWriter::VisitOMPRequiresDecl(OMPRequiresDecl *D) {
1869   Record.writeOMPChildren(D->Data);
1870   VisitDecl(D);
1871   Code = serialization::DECL_OMP_REQUIRES;
1872 }
1873 
1874 void ASTDeclWriter::VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D) {
1875   VisitValueDecl(D);
1876   Record.AddSourceLocation(D->getBeginLoc());
1877   Record.AddStmt(D->getCombinerIn());
1878   Record.AddStmt(D->getCombinerOut());
1879   Record.AddStmt(D->getCombiner());
1880   Record.AddStmt(D->getInitOrig());
1881   Record.AddStmt(D->getInitPriv());
1882   Record.AddStmt(D->getInitializer());
1883   Record.push_back(D->getInitializerKind());
1884   Record.AddDeclRef(D->getPrevDeclInScope());
1885   Code = serialization::DECL_OMP_DECLARE_REDUCTION;
1886 }
1887 
1888 void ASTDeclWriter::VisitOMPDeclareMapperDecl(OMPDeclareMapperDecl *D) {
1889   Record.writeOMPChildren(D->Data);
1890   VisitValueDecl(D);
1891   Record.AddDeclarationName(D->getVarName());
1892   Record.AddDeclRef(D->getPrevDeclInScope());
1893   Code = serialization::DECL_OMP_DECLARE_MAPPER;
1894 }
1895 
1896 void ASTDeclWriter::VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D) {
1897   VisitVarDecl(D);
1898   Code = serialization::DECL_OMP_CAPTUREDEXPR;
1899 }
1900 
1901 //===----------------------------------------------------------------------===//
1902 // ASTWriter Implementation
1903 //===----------------------------------------------------------------------===//
1904 
1905 void ASTWriter::WriteDeclAbbrevs() {
1906   using namespace llvm;
1907 
1908   std::shared_ptr<BitCodeAbbrev> Abv;
1909 
1910   // Abbreviation for DECL_FIELD
1911   Abv = std::make_shared<BitCodeAbbrev>();
1912   Abv->Add(BitCodeAbbrevOp(serialization::DECL_FIELD));
1913   // Decl
1914   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1915   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1916   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1917   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1918   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1919   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1920   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1921   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1922   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1923   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1924   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1925   // NamedDecl
1926   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1927   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1928   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1929   // ValueDecl
1930   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1931   // DeclaratorDecl
1932   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1933   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1934   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
1935   // FieldDecl
1936   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1937   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
1938   // Type Source Info
1939   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1940   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1941   DeclFieldAbbrev = Stream.EmitAbbrev(std::move(Abv));
1942 
1943   // Abbreviation for DECL_OBJC_IVAR
1944   Abv = std::make_shared<BitCodeAbbrev>();
1945   Abv->Add(BitCodeAbbrevOp(serialization::DECL_OBJC_IVAR));
1946   // Decl
1947   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1948   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1949   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1950   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1951   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1952   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1953   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1954   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1955   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1956   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1957   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1958   // NamedDecl
1959   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1960   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1961   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1962   // ValueDecl
1963   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1964   // DeclaratorDecl
1965   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1966   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1967   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
1968   // FieldDecl
1969   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1970   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
1971   // ObjC Ivar
1972   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getAccessControl
1973   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getSynthesize
1974   // Type Source Info
1975   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1976   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1977   DeclObjCIvarAbbrev = Stream.EmitAbbrev(std::move(Abv));
1978 
1979   // Abbreviation for DECL_ENUM
1980   Abv = std::make_shared<BitCodeAbbrev>();
1981   Abv->Add(BitCodeAbbrevOp(serialization::DECL_ENUM));
1982   // Redeclarable
1983   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1984   // Decl
1985   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1986   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1987   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1988   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1989   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1990   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1991   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1992   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1993   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1994   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1995   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1996   // NamedDecl
1997   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1998   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1999   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2000   // TypeDecl
2001   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
2002   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
2003   // TagDecl
2004   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
2005   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
2006   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
2007   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
2008   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
2009   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
2010   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2011   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2012   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
2013   // EnumDecl
2014   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddTypeRef
2015   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IntegerType
2016   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getPromotionType
2017   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumPositiveBits
2018   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumNegativeBits
2019   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScoped
2020   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScopedUsingClassTag
2021   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isFixed
2022   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));// ODRHash
2023   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InstantiatedMembEnum
2024   // DC
2025   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
2026   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
2027   DeclEnumAbbrev = Stream.EmitAbbrev(std::move(Abv));
2028 
2029   // Abbreviation for DECL_RECORD
2030   Abv = std::make_shared<BitCodeAbbrev>();
2031   Abv->Add(BitCodeAbbrevOp(serialization::DECL_RECORD));
2032   // Redeclarable
2033   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2034   // Decl
2035   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2036   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2037   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2038   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2039   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2040   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2041   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2042   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2043   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2044   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2045   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2046   // NamedDecl
2047   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2048   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2049   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2050   // TypeDecl
2051   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
2052   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
2053   // TagDecl
2054   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
2055   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
2056   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
2057   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
2058   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
2059   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
2060   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2061   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2062   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
2063   // RecordDecl
2064   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // FlexibleArrayMember
2065   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // AnonymousStructUnion
2066   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasObjectMember
2067   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasVolatileMember
2068 
2069   // isNonTrivialToPrimitiveDefaultInitialize
2070   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2071   // isNonTrivialToPrimitiveCopy
2072   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2073   // isNonTrivialToPrimitiveDestroy
2074   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2075   // hasNonTrivialToPrimitiveDefaultInitializeCUnion
2076   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2077   // hasNonTrivialToPrimitiveDestructCUnion
2078   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2079   // hasNonTrivialToPrimitiveCopyCUnion
2080   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2081   // isParamDestroyedInCallee
2082   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2083   // getArgPassingRestrictions
2084   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));
2085 
2086   // DC
2087   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
2088   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
2089   DeclRecordAbbrev = Stream.EmitAbbrev(std::move(Abv));
2090 
2091   // Abbreviation for DECL_PARM_VAR
2092   Abv = std::make_shared<BitCodeAbbrev>();
2093   Abv->Add(BitCodeAbbrevOp(serialization::DECL_PARM_VAR));
2094   // Redeclarable
2095   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2096   // Decl
2097   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2098   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2099   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2100   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2101   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2102   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2103   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2104   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2105   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2106   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2107   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2108   // NamedDecl
2109   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2110   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2111   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2112   // ValueDecl
2113   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2114   // DeclaratorDecl
2115   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
2116   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
2117   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
2118   // VarDecl
2119   Abv->Add(BitCodeAbbrevOp(0));                       // SClass
2120   Abv->Add(BitCodeAbbrevOp(0));                       // TSCSpec
2121   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
2122   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isARCPseudoStrong
2123   Abv->Add(BitCodeAbbrevOp(0));                       // Linkage
2124   Abv->Add(BitCodeAbbrevOp(0));                       // HasInit
2125   Abv->Add(BitCodeAbbrevOp(0));                   // HasMemberSpecializationInfo
2126   // ParmVarDecl
2127   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsObjCMethodParameter
2128   Abv->Add(BitCodeAbbrevOp(0));                       // ScopeDepth
2129   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ScopeIndex
2130   Abv->Add(BitCodeAbbrevOp(0));                       // ObjCDeclQualifier
2131   Abv->Add(BitCodeAbbrevOp(0));                       // KNRPromoted
2132   Abv->Add(BitCodeAbbrevOp(0));                       // HasInheritedDefaultArg
2133   Abv->Add(BitCodeAbbrevOp(0));                   // HasUninstantiatedDefaultArg
2134   // Type Source Info
2135   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2136   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2137   DeclParmVarAbbrev = Stream.EmitAbbrev(std::move(Abv));
2138 
2139   // Abbreviation for DECL_TYPEDEF
2140   Abv = std::make_shared<BitCodeAbbrev>();
2141   Abv->Add(BitCodeAbbrevOp(serialization::DECL_TYPEDEF));
2142   // Redeclarable
2143   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2144   // Decl
2145   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2146   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2147   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2148   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2149   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2150   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isUsed
2151   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isReferenced
2152   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2153   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // C++ AccessSpecifier
2154   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2155   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2156   // NamedDecl
2157   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2158   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2159   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2160   // TypeDecl
2161   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
2162   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
2163   // TypedefDecl
2164   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2165   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2166   DeclTypedefAbbrev = Stream.EmitAbbrev(std::move(Abv));
2167 
2168   // Abbreviation for DECL_VAR
2169   Abv = std::make_shared<BitCodeAbbrev>();
2170   Abv->Add(BitCodeAbbrevOp(serialization::DECL_VAR));
2171   // Redeclarable
2172   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2173   // Decl
2174   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2175   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2176   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2177   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2178   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2179   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2180   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2181   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2182   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2183   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2184   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2185   // NamedDecl
2186   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2187   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2188   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2189   // ValueDecl
2190   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2191   // DeclaratorDecl
2192   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
2193   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
2194   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
2195   // VarDecl
2196   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // SClass
2197   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // TSCSpec
2198   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // InitStyle
2199   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isARCPseudoStrong
2200   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsThisDeclarationADemotedDefinition
2201   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isExceptionVariable
2202   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isNRVOVariable
2203   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCXXForRangeDecl
2204   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isObjCForDecl
2205   Abv->Add(BitCodeAbbrevOp(0));                         // isInline
2206   Abv->Add(BitCodeAbbrevOp(0));                         // isInlineSpecified
2207   Abv->Add(BitCodeAbbrevOp(0));                         // isConstexpr
2208   Abv->Add(BitCodeAbbrevOp(0));                         // isInitCapture
2209   Abv->Add(BitCodeAbbrevOp(0));                         // isPrevDeclInSameScope
2210   Abv->Add(BitCodeAbbrevOp(0));                         // ImplicitParamKind
2211   Abv->Add(BitCodeAbbrevOp(0));                         // EscapingByref
2212   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
2213   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // HasConstant*
2214   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // VarKind (local enum)
2215   // Type Source Info
2216   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2217   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2218   DeclVarAbbrev = Stream.EmitAbbrev(std::move(Abv));
2219 
2220   // Abbreviation for DECL_CXX_METHOD
2221   Abv = std::make_shared<BitCodeAbbrev>();
2222   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CXX_METHOD));
2223   // RedeclarableDecl
2224   Abv->Add(BitCodeAbbrevOp(0));                         // CanonicalDecl
2225   // Decl
2226   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // DeclContext
2227   Abv->Add(BitCodeAbbrevOp(0));                         // LexicalDeclContext
2228   Abv->Add(BitCodeAbbrevOp(0));                         // Invalid
2229   Abv->Add(BitCodeAbbrevOp(0));                         // HasAttrs
2230   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Implicit
2231   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Used
2232   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Referenced
2233   Abv->Add(BitCodeAbbrevOp(0));                         // InObjCContainer
2234   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // Access
2235   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ModulePrivate
2236   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SubmoduleID
2237   // NamedDecl
2238   Abv->Add(BitCodeAbbrevOp(DeclarationName::Identifier)); // NameKind
2239   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Identifier
2240   Abv->Add(BitCodeAbbrevOp(0));                         // AnonDeclNumber
2241   // ValueDecl
2242   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Type
2243   // DeclaratorDecl
2244   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InnerLocStart
2245   Abv->Add(BitCodeAbbrevOp(0));                         // HasExtInfo
2246   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // TSIType
2247   // FunctionDecl
2248   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 11)); // IDNS
2249   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // StorageClass
2250   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Inline
2251   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // InlineSpecified
2252   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // VirtualAsWritten
2253   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Pure
2254   Abv->Add(BitCodeAbbrevOp(0));                         // HasInheritedProto
2255   Abv->Add(BitCodeAbbrevOp(1));                         // HasWrittenProto
2256   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Deleted
2257   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Trivial
2258   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // TrivialForCall
2259   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Defaulted
2260   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ExplicitlyDefaulted
2261   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ImplicitReturnZero
2262   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // Constexpr
2263   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // UsesSEHTry
2264   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // SkippedBody
2265   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // MultiVersion
2266   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // LateParsed
2267   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
2268   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LocEnd
2269   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32)); // ODRHash
2270   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // TemplateKind
2271   // This Array slurps the rest of the record. Fortunately we want to encode
2272   // (nearly) all the remaining (variable number of) fields in the same way.
2273   //
2274   // This is the function template information if any, then
2275   //         NumParams and Params[] from FunctionDecl, and
2276   //         NumOverriddenMethods, OverriddenMethods[] from CXXMethodDecl.
2277   //
2278   //  Add an AbbrevOp for 'size then elements' and use it here.
2279   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2280   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2281   DeclCXXMethodAbbrev = Stream.EmitAbbrev(std::move(Abv));
2282 
2283   // Abbreviation for EXPR_DECL_REF
2284   Abv = std::make_shared<BitCodeAbbrev>();
2285   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_DECL_REF));
2286   //Stmt
2287   // Expr
2288   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2289   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2290   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2291   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2292   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2293   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ContainsErrors
2294   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2295   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2296   //DeclRefExpr
2297   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HasQualifier
2298   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //GetDeclFound
2299   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ExplicitTemplateArgs
2300   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HadMultipleCandidates
2301   Abv->Add(BitCodeAbbrevOp(0)); // RefersToEnclosingVariableOrCapture
2302   Abv->Add(BitCodeAbbrevOp(0)); // NonOdrUseReason
2303   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclRef
2304   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2305   DeclRefExprAbbrev = Stream.EmitAbbrev(std::move(Abv));
2306 
2307   // Abbreviation for EXPR_INTEGER_LITERAL
2308   Abv = std::make_shared<BitCodeAbbrev>();
2309   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_INTEGER_LITERAL));
2310   //Stmt
2311   // Expr
2312   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2313   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2314   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2315   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2316   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2317   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ContainsErrors
2318   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2319   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2320   //Integer Literal
2321   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2322   Abv->Add(BitCodeAbbrevOp(32));                      // Bit Width
2323   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Value
2324   IntegerLiteralAbbrev = Stream.EmitAbbrev(std::move(Abv));
2325 
2326   // Abbreviation for EXPR_CHARACTER_LITERAL
2327   Abv = std::make_shared<BitCodeAbbrev>();
2328   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_CHARACTER_LITERAL));
2329   //Stmt
2330   // Expr
2331   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2332   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2333   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2334   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2335   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2336   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ContainsErrors
2337   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2338   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2339   //Character Literal
2340   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getValue
2341   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2342   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // getKind
2343   CharacterLiteralAbbrev = Stream.EmitAbbrev(std::move(Abv));
2344 
2345   // Abbreviation for EXPR_IMPLICIT_CAST
2346   Abv = std::make_shared<BitCodeAbbrev>();
2347   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_IMPLICIT_CAST));
2348   // Stmt
2349   // Expr
2350   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2351   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2352   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2353   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2354   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2355   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ContainsErrors
2356   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2357   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2358   // CastExpr
2359   Abv->Add(BitCodeAbbrevOp(0)); // PathSize
2360   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // HasFPFeatures
2361   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 6)); // CastKind
2362   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // PartOfExplicitCast
2363   // ImplicitCastExpr
2364   ExprImplicitCastAbbrev = Stream.EmitAbbrev(std::move(Abv));
2365 
2366   Abv = std::make_shared<BitCodeAbbrev>();
2367   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_LEXICAL));
2368   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2369   DeclContextLexicalAbbrev = Stream.EmitAbbrev(std::move(Abv));
2370 
2371   Abv = std::make_shared<BitCodeAbbrev>();
2372   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_VISIBLE));
2373   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2374   DeclContextVisibleLookupAbbrev = Stream.EmitAbbrev(std::move(Abv));
2375 }
2376 
2377 /// isRequiredDecl - Check if this is a "required" Decl, which must be seen by
2378 /// consumers of the AST.
2379 ///
2380 /// Such decls will always be deserialized from the AST file, so we would like
2381 /// this to be as restrictive as possible. Currently the predicate is driven by
2382 /// code generation requirements, if other clients have a different notion of
2383 /// what is "required" then we may have to consider an alternate scheme where
2384 /// clients can iterate over the top-level decls and get information on them,
2385 /// without necessary deserializing them. We could explicitly require such
2386 /// clients to use a separate API call to "realize" the decl. This should be
2387 /// relatively painless since they would presumably only do it for top-level
2388 /// decls.
2389 static bool isRequiredDecl(const Decl *D, ASTContext &Context,
2390                            bool WritingModule) {
2391   // An ObjCMethodDecl is never considered as "required" because its
2392   // implementation container always is.
2393 
2394   // File scoped assembly or obj-c or OMP declare target implementation must be
2395   // seen.
2396   if (isa<FileScopeAsmDecl>(D) || isa<ObjCImplDecl>(D))
2397     return true;
2398 
2399   if (WritingModule && isPartOfPerModuleInitializer(D)) {
2400     // These declarations are part of the module initializer, and are emitted
2401     // if and when the module is imported, rather than being emitted eagerly.
2402     return false;
2403   }
2404 
2405   return Context.DeclMustBeEmitted(D);
2406 }
2407 
2408 void ASTWriter::WriteDecl(ASTContext &Context, Decl *D) {
2409   PrettyDeclStackTraceEntry CrashInfo(Context, D, SourceLocation(),
2410                                       "serializing");
2411 
2412   // Determine the ID for this declaration.
2413   serialization::DeclID ID;
2414   assert(!D->isFromASTFile() && "should not be emitting imported decl");
2415   serialization::DeclID &IDR = DeclIDs[D];
2416   if (IDR == 0)
2417     IDR = NextDeclID++;
2418 
2419   ID = IDR;
2420 
2421   assert(ID >= FirstDeclID && "invalid decl ID");
2422 
2423   RecordData Record;
2424   ASTDeclWriter W(*this, Context, Record);
2425 
2426   // Build a record for this declaration
2427   W.Visit(D);
2428 
2429   // Emit this declaration to the bitstream.
2430   uint64_t Offset = W.Emit(D);
2431 
2432   // Record the offset for this declaration
2433   SourceLocation Loc = D->getLocation();
2434   unsigned Index = ID - FirstDeclID;
2435   if (DeclOffsets.size() == Index)
2436     DeclOffsets.emplace_back(Loc, Offset, DeclTypesBlockStartOffset);
2437   else if (DeclOffsets.size() < Index) {
2438     // FIXME: Can/should this happen?
2439     DeclOffsets.resize(Index+1);
2440     DeclOffsets[Index].setLocation(Loc);
2441     DeclOffsets[Index].setBitOffset(Offset, DeclTypesBlockStartOffset);
2442   } else {
2443     llvm_unreachable("declarations should be emitted in ID order");
2444   }
2445 
2446   SourceManager &SM = Context.getSourceManager();
2447   if (Loc.isValid() && SM.isLocalSourceLocation(Loc))
2448     associateDeclWithFile(D, ID);
2449 
2450   // Note declarations that should be deserialized eagerly so that we can add
2451   // them to a record in the AST file later.
2452   if (isRequiredDecl(D, Context, WritingModule))
2453     EagerlyDeserializedDecls.push_back(ID);
2454 }
2455 
2456 void ASTRecordWriter::AddFunctionDefinition(const FunctionDecl *FD) {
2457   // Switch case IDs are per function body.
2458   Writer->ClearSwitchCaseIDs();
2459 
2460   assert(FD->doesThisDeclarationHaveABody());
2461   bool ModulesCodegen = false;
2462   if (!FD->isDependentContext()) {
2463     Optional<GVALinkage> Linkage;
2464     if (Writer->WritingModule &&
2465         Writer->WritingModule->Kind == Module::ModuleInterfaceUnit) {
2466       // When building a C++ Modules TS module interface unit, a strong
2467       // definition in the module interface is provided by the compilation of
2468       // that module interface unit, not by its users. (Inline functions are
2469       // still emitted in module users.)
2470       Linkage = Writer->Context->GetGVALinkageForFunction(FD);
2471       ModulesCodegen = *Linkage == GVA_StrongExternal;
2472     }
2473     if (Writer->Context->getLangOpts().ModulesCodegen ||
2474         (FD->hasAttr<DLLExportAttr>() &&
2475          Writer->Context->getLangOpts().BuildingPCHWithObjectFile)) {
2476 
2477       // Under -fmodules-codegen, codegen is performed for all non-internal,
2478       // non-always_inline functions, unless they are available elsewhere.
2479       if (!FD->hasAttr<AlwaysInlineAttr>()) {
2480         if (!Linkage)
2481           Linkage = Writer->Context->GetGVALinkageForFunction(FD);
2482         ModulesCodegen =
2483             *Linkage != GVA_Internal && *Linkage != GVA_AvailableExternally;
2484       }
2485     }
2486   }
2487   Record->push_back(ModulesCodegen);
2488   if (ModulesCodegen)
2489     Writer->ModularCodegenDecls.push_back(Writer->GetDeclRef(FD));
2490   if (auto *CD = dyn_cast<CXXConstructorDecl>(FD)) {
2491     Record->push_back(CD->getNumCtorInitializers());
2492     if (CD->getNumCtorInitializers())
2493       AddCXXCtorInitializers(
2494           llvm::makeArrayRef(CD->init_begin(), CD->init_end()));
2495   }
2496   AddStmt(FD->getBody());
2497 }
2498