1 //===--- ASTWriterDecl.cpp - Declaration Serialization --------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //  This file implements serialization for Declarations.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "ASTCommon.h"
15 #include "clang/AST/DeclCXX.h"
16 #include "clang/AST/DeclContextInternals.h"
17 #include "clang/AST/DeclTemplate.h"
18 #include "clang/AST/DeclVisitor.h"
19 #include "clang/AST/Expr.h"
20 #include "clang/AST/PrettyDeclStackTrace.h"
21 #include "clang/Basic/SourceManager.h"
22 #include "clang/Serialization/ASTReader.h"
23 #include "clang/Serialization/ASTWriter.h"
24 #include "llvm/Bitcode/BitstreamWriter.h"
25 #include "llvm/Support/ErrorHandling.h"
26 using namespace clang;
27 using namespace serialization;
28 
29 //===----------------------------------------------------------------------===//
30 // Declaration serialization
31 //===----------------------------------------------------------------------===//
32 
33 namespace clang {
34   class ASTDeclWriter : public DeclVisitor<ASTDeclWriter, void> {
35     ASTWriter &Writer;
36     ASTContext &Context;
37     ASTRecordWriter Record;
38 
39     serialization::DeclCode Code;
40     unsigned AbbrevToUse;
41 
42   public:
43     ASTDeclWriter(ASTWriter &Writer, ASTContext &Context,
44                   ASTWriter::RecordDataImpl &Record)
45         : Writer(Writer), Context(Context), Record(Writer, Record),
46           Code((serialization::DeclCode)0), AbbrevToUse(0) {}
47 
48     uint64_t Emit(Decl *D) {
49       if (!Code)
50         llvm::report_fatal_error(StringRef("unexpected declaration kind '") +
51             D->getDeclKindName() + "'");
52       return Record.Emit(Code, AbbrevToUse);
53     }
54 
55     void Visit(Decl *D);
56 
57     void VisitDecl(Decl *D);
58     void VisitPragmaCommentDecl(PragmaCommentDecl *D);
59     void VisitPragmaDetectMismatchDecl(PragmaDetectMismatchDecl *D);
60     void VisitTranslationUnitDecl(TranslationUnitDecl *D);
61     void VisitNamedDecl(NamedDecl *D);
62     void VisitLabelDecl(LabelDecl *LD);
63     void VisitNamespaceDecl(NamespaceDecl *D);
64     void VisitUsingDirectiveDecl(UsingDirectiveDecl *D);
65     void VisitNamespaceAliasDecl(NamespaceAliasDecl *D);
66     void VisitTypeDecl(TypeDecl *D);
67     void VisitTypedefNameDecl(TypedefNameDecl *D);
68     void VisitTypedefDecl(TypedefDecl *D);
69     void VisitTypeAliasDecl(TypeAliasDecl *D);
70     void VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D);
71     void VisitTagDecl(TagDecl *D);
72     void VisitEnumDecl(EnumDecl *D);
73     void VisitRecordDecl(RecordDecl *D);
74     void VisitCXXRecordDecl(CXXRecordDecl *D);
75     void VisitClassTemplateSpecializationDecl(
76                                             ClassTemplateSpecializationDecl *D);
77     void VisitClassTemplatePartialSpecializationDecl(
78                                      ClassTemplatePartialSpecializationDecl *D);
79     void VisitVarTemplateSpecializationDecl(VarTemplateSpecializationDecl *D);
80     void VisitVarTemplatePartialSpecializationDecl(
81         VarTemplatePartialSpecializationDecl *D);
82     void VisitClassScopeFunctionSpecializationDecl(
83                                        ClassScopeFunctionSpecializationDecl *D);
84     void VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
85     void VisitValueDecl(ValueDecl *D);
86     void VisitEnumConstantDecl(EnumConstantDecl *D);
87     void VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D);
88     void VisitDeclaratorDecl(DeclaratorDecl *D);
89     void VisitFunctionDecl(FunctionDecl *D);
90     void VisitCXXDeductionGuideDecl(CXXDeductionGuideDecl *D);
91     void VisitCXXMethodDecl(CXXMethodDecl *D);
92     void VisitCXXConstructorDecl(CXXConstructorDecl *D);
93     void VisitCXXDestructorDecl(CXXDestructorDecl *D);
94     void VisitCXXConversionDecl(CXXConversionDecl *D);
95     void VisitFieldDecl(FieldDecl *D);
96     void VisitMSPropertyDecl(MSPropertyDecl *D);
97     void VisitIndirectFieldDecl(IndirectFieldDecl *D);
98     void VisitVarDecl(VarDecl *D);
99     void VisitImplicitParamDecl(ImplicitParamDecl *D);
100     void VisitParmVarDecl(ParmVarDecl *D);
101     void VisitDecompositionDecl(DecompositionDecl *D);
102     void VisitBindingDecl(BindingDecl *D);
103     void VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
104     void VisitTemplateDecl(TemplateDecl *D);
105     void VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D);
106     void VisitClassTemplateDecl(ClassTemplateDecl *D);
107     void VisitVarTemplateDecl(VarTemplateDecl *D);
108     void VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
109     void VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
110     void VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D);
111     void VisitUsingDecl(UsingDecl *D);
112     void VisitUsingPackDecl(UsingPackDecl *D);
113     void VisitUsingShadowDecl(UsingShadowDecl *D);
114     void VisitConstructorUsingShadowDecl(ConstructorUsingShadowDecl *D);
115     void VisitLinkageSpecDecl(LinkageSpecDecl *D);
116     void VisitExportDecl(ExportDecl *D);
117     void VisitFileScopeAsmDecl(FileScopeAsmDecl *D);
118     void VisitImportDecl(ImportDecl *D);
119     void VisitAccessSpecDecl(AccessSpecDecl *D);
120     void VisitFriendDecl(FriendDecl *D);
121     void VisitFriendTemplateDecl(FriendTemplateDecl *D);
122     void VisitStaticAssertDecl(StaticAssertDecl *D);
123     void VisitBlockDecl(BlockDecl *D);
124     void VisitCapturedDecl(CapturedDecl *D);
125     void VisitEmptyDecl(EmptyDecl *D);
126 
127     void VisitDeclContext(DeclContext *DC);
128     template <typename T> void VisitRedeclarable(Redeclarable<T> *D);
129 
130 
131     // FIXME: Put in the same order is DeclNodes.td?
132     void VisitObjCMethodDecl(ObjCMethodDecl *D);
133     void VisitObjCTypeParamDecl(ObjCTypeParamDecl *D);
134     void VisitObjCContainerDecl(ObjCContainerDecl *D);
135     void VisitObjCInterfaceDecl(ObjCInterfaceDecl *D);
136     void VisitObjCIvarDecl(ObjCIvarDecl *D);
137     void VisitObjCProtocolDecl(ObjCProtocolDecl *D);
138     void VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D);
139     void VisitObjCCategoryDecl(ObjCCategoryDecl *D);
140     void VisitObjCImplDecl(ObjCImplDecl *D);
141     void VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D);
142     void VisitObjCImplementationDecl(ObjCImplementationDecl *D);
143     void VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D);
144     void VisitObjCPropertyDecl(ObjCPropertyDecl *D);
145     void VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D);
146     void VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D);
147     void VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D);
148     void VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D);
149 
150     /// Add an Objective-C type parameter list to the given record.
151     void AddObjCTypeParamList(ObjCTypeParamList *typeParams) {
152       // Empty type parameter list.
153       if (!typeParams) {
154         Record.push_back(0);
155         return;
156       }
157 
158       Record.push_back(typeParams->size());
159       for (auto typeParam : *typeParams) {
160         Record.AddDeclRef(typeParam);
161       }
162       Record.AddSourceLocation(typeParams->getLAngleLoc());
163       Record.AddSourceLocation(typeParams->getRAngleLoc());
164     }
165 
166     /// Add to the record the first declaration from each module file that
167     /// provides a declaration of D. The intent is to provide a sufficient
168     /// set such that reloading this set will load all current redeclarations.
169     void AddFirstDeclFromEachModule(const Decl *D, bool IncludeLocal) {
170       llvm::MapVector<ModuleFile*, const Decl*> Firsts;
171       // FIXME: We can skip entries that we know are implied by others.
172       for (const Decl *R = D->getMostRecentDecl(); R; R = R->getPreviousDecl()) {
173         if (R->isFromASTFile())
174           Firsts[Writer.Chain->getOwningModuleFile(R)] = R;
175         else if (IncludeLocal)
176           Firsts[nullptr] = R;
177       }
178       for (const auto &F : Firsts)
179         Record.AddDeclRef(F.second);
180     }
181 
182     /// Get the specialization decl from an entry in the specialization list.
183     template <typename EntryType>
184     typename RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::DeclType *
185     getSpecializationDecl(EntryType &T) {
186       return RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::getDecl(&T);
187     }
188 
189     /// Get the list of partial specializations from a template's common ptr.
190     template<typename T>
191     decltype(T::PartialSpecializations) &getPartialSpecializations(T *Common) {
192       return Common->PartialSpecializations;
193     }
194     ArrayRef<Decl> getPartialSpecializations(FunctionTemplateDecl::Common *) {
195       return None;
196     }
197 
198     template<typename DeclTy>
199     void AddTemplateSpecializations(DeclTy *D) {
200       auto *Common = D->getCommonPtr();
201 
202       // If we have any lazy specializations, and the external AST source is
203       // our chained AST reader, we can just write out the DeclIDs. Otherwise,
204       // we need to resolve them to actual declarations.
205       if (Writer.Chain != Writer.Context->getExternalSource() &&
206           Common->LazySpecializations) {
207         D->LoadLazySpecializations();
208         assert(!Common->LazySpecializations);
209       }
210 
211       ArrayRef<DeclID> LazySpecializations;
212       if (auto *LS = Common->LazySpecializations)
213         LazySpecializations = llvm::makeArrayRef(LS + 1, LS[0]);
214 
215       // Add a slot to the record for the number of specializations.
216       unsigned I = Record.size();
217       Record.push_back(0);
218 
219       // AddFirstDeclFromEachModule might trigger deserialization, invalidating
220       // *Specializations iterators.
221       llvm::SmallVector<const Decl*, 16> Specs;
222       for (auto &Entry : Common->Specializations)
223         Specs.push_back(getSpecializationDecl(Entry));
224       for (auto &Entry : getPartialSpecializations(Common))
225         Specs.push_back(getSpecializationDecl(Entry));
226 
227       for (auto *D : Specs) {
228         assert(D->isCanonicalDecl() && "non-canonical decl in set");
229         AddFirstDeclFromEachModule(D, /*IncludeLocal*/true);
230       }
231       Record.append(LazySpecializations.begin(), LazySpecializations.end());
232 
233       // Update the size entry we added earlier.
234       Record[I] = Record.size() - I - 1;
235     }
236 
237     /// Ensure that this template specialization is associated with the specified
238     /// template on reload.
239     void RegisterTemplateSpecialization(const Decl *Template,
240                                         const Decl *Specialization) {
241       Template = Template->getCanonicalDecl();
242 
243       // If the canonical template is local, we'll write out this specialization
244       // when we emit it.
245       // FIXME: We can do the same thing if there is any local declaration of
246       // the template, to avoid emitting an update record.
247       if (!Template->isFromASTFile())
248         return;
249 
250       // We only need to associate the first local declaration of the
251       // specialization. The other declarations will get pulled in by it.
252       if (Writer.getFirstLocalDecl(Specialization) != Specialization)
253         return;
254 
255       Writer.DeclUpdates[Template].push_back(ASTWriter::DeclUpdate(
256           UPD_CXX_ADDED_TEMPLATE_SPECIALIZATION, Specialization));
257     }
258   };
259 }
260 
261 void ASTDeclWriter::Visit(Decl *D) {
262   DeclVisitor<ASTDeclWriter>::Visit(D);
263 
264   // Source locations require array (variable-length) abbreviations.  The
265   // abbreviation infrastructure requires that arrays are encoded last, so
266   // we handle it here in the case of those classes derived from DeclaratorDecl
267   if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D)) {
268     if (auto *TInfo = DD->getTypeSourceInfo())
269       Record.AddTypeLoc(TInfo->getTypeLoc());
270   }
271 
272   // Handle FunctionDecl's body here and write it after all other Stmts/Exprs
273   // have been written. We want it last because we will not read it back when
274   // retrieving it from the AST, we'll just lazily set the offset.
275   if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
276     Record.push_back(FD->doesThisDeclarationHaveABody());
277     if (FD->doesThisDeclarationHaveABody())
278       Record.AddFunctionDefinition(FD);
279   }
280 
281   // If this declaration is also a DeclContext, write blocks for the
282   // declarations that lexically stored inside its context and those
283   // declarations that are visible from its context.
284   if (DeclContext *DC = dyn_cast<DeclContext>(D))
285     VisitDeclContext(DC);
286 }
287 
288 void ASTDeclWriter::VisitDecl(Decl *D) {
289   Record.AddDeclRef(cast_or_null<Decl>(D->getDeclContext()));
290   if (D->getDeclContext() != D->getLexicalDeclContext())
291     Record.AddDeclRef(cast_or_null<Decl>(D->getLexicalDeclContext()));
292   else
293     Record.push_back(0);
294   Record.push_back(D->isInvalidDecl());
295   Record.push_back(D->hasAttrs());
296   if (D->hasAttrs())
297     Record.AddAttributes(D->getAttrs());
298   Record.push_back(D->isImplicit());
299   Record.push_back(D->isUsed(false));
300   Record.push_back(D->isReferenced());
301   Record.push_back(D->isTopLevelDeclInObjCContainer());
302   Record.push_back(D->getAccess());
303   Record.push_back(D->isModulePrivate());
304   Record.push_back(Writer.getSubmoduleID(D->getOwningModule()));
305 
306   // If this declaration injected a name into a context different from its
307   // lexical context, and that context is an imported namespace, we need to
308   // update its visible declarations to include this name.
309   //
310   // This happens when we instantiate a class with a friend declaration or a
311   // function with a local extern declaration, for instance.
312   //
313   // FIXME: Can we handle this in AddedVisibleDecl instead?
314   if (D->isOutOfLine()) {
315     auto *DC = D->getDeclContext();
316     while (auto *NS = dyn_cast<NamespaceDecl>(DC->getRedeclContext())) {
317       if (!NS->isFromASTFile())
318         break;
319       Writer.UpdatedDeclContexts.insert(NS->getPrimaryContext());
320       if (!NS->isInlineNamespace())
321         break;
322       DC = NS->getParent();
323     }
324   }
325 }
326 
327 void ASTDeclWriter::VisitPragmaCommentDecl(PragmaCommentDecl *D) {
328   StringRef Arg = D->getArg();
329   Record.push_back(Arg.size());
330   VisitDecl(D);
331   Record.AddSourceLocation(D->getLocStart());
332   Record.push_back(D->getCommentKind());
333   Record.AddString(Arg);
334   Code = serialization::DECL_PRAGMA_COMMENT;
335 }
336 
337 void ASTDeclWriter::VisitPragmaDetectMismatchDecl(
338     PragmaDetectMismatchDecl *D) {
339   StringRef Name = D->getName();
340   StringRef Value = D->getValue();
341   Record.push_back(Name.size() + 1 + Value.size());
342   VisitDecl(D);
343   Record.AddSourceLocation(D->getLocStart());
344   Record.AddString(Name);
345   Record.AddString(Value);
346   Code = serialization::DECL_PRAGMA_DETECT_MISMATCH;
347 }
348 
349 void ASTDeclWriter::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
350   llvm_unreachable("Translation units aren't directly serialized");
351 }
352 
353 void ASTDeclWriter::VisitNamedDecl(NamedDecl *D) {
354   VisitDecl(D);
355   Record.AddDeclarationName(D->getDeclName());
356   Record.push_back(needsAnonymousDeclarationNumber(D)
357                        ? Writer.getAnonymousDeclarationNumber(D)
358                        : 0);
359 }
360 
361 void ASTDeclWriter::VisitTypeDecl(TypeDecl *D) {
362   VisitNamedDecl(D);
363   Record.AddSourceLocation(D->getLocStart());
364   Record.AddTypeRef(QualType(D->getTypeForDecl(), 0));
365 }
366 
367 void ASTDeclWriter::VisitTypedefNameDecl(TypedefNameDecl *D) {
368   VisitRedeclarable(D);
369   VisitTypeDecl(D);
370   Record.AddTypeSourceInfo(D->getTypeSourceInfo());
371   Record.push_back(D->isModed());
372   if (D->isModed())
373     Record.AddTypeRef(D->getUnderlyingType());
374   Record.AddDeclRef(D->getAnonDeclWithTypedefName(false));
375 }
376 
377 void ASTDeclWriter::VisitTypedefDecl(TypedefDecl *D) {
378   VisitTypedefNameDecl(D);
379   if (D->getDeclContext() == D->getLexicalDeclContext() &&
380       !D->hasAttrs() &&
381       !D->isImplicit() &&
382       D->getFirstDecl() == D->getMostRecentDecl() &&
383       !D->isInvalidDecl() &&
384       !D->isTopLevelDeclInObjCContainer() &&
385       !D->isModulePrivate() &&
386       !needsAnonymousDeclarationNumber(D) &&
387       D->getDeclName().getNameKind() == DeclarationName::Identifier)
388     AbbrevToUse = Writer.getDeclTypedefAbbrev();
389 
390   Code = serialization::DECL_TYPEDEF;
391 }
392 
393 void ASTDeclWriter::VisitTypeAliasDecl(TypeAliasDecl *D) {
394   VisitTypedefNameDecl(D);
395   Record.AddDeclRef(D->getDescribedAliasTemplate());
396   Code = serialization::DECL_TYPEALIAS;
397 }
398 
399 void ASTDeclWriter::VisitTagDecl(TagDecl *D) {
400   VisitRedeclarable(D);
401   VisitTypeDecl(D);
402   Record.push_back(D->getIdentifierNamespace());
403   Record.push_back((unsigned)D->getTagKind()); // FIXME: stable encoding
404   if (!isa<CXXRecordDecl>(D))
405     Record.push_back(D->isCompleteDefinition());
406   Record.push_back(D->isEmbeddedInDeclarator());
407   Record.push_back(D->isFreeStanding());
408   Record.push_back(D->isCompleteDefinitionRequired());
409   Record.AddSourceRange(D->getBraceRange());
410 
411   if (D->hasExtInfo()) {
412     Record.push_back(1);
413     Record.AddQualifierInfo(*D->getExtInfo());
414   } else if (auto *TD = D->getTypedefNameForAnonDecl()) {
415     Record.push_back(2);
416     Record.AddDeclRef(TD);
417     Record.AddIdentifierRef(TD->getDeclName().getAsIdentifierInfo());
418   } else {
419     Record.push_back(0);
420   }
421 }
422 
423 void ASTDeclWriter::VisitEnumDecl(EnumDecl *D) {
424   VisitTagDecl(D);
425   Record.AddTypeSourceInfo(D->getIntegerTypeSourceInfo());
426   if (!D->getIntegerTypeSourceInfo())
427     Record.AddTypeRef(D->getIntegerType());
428   Record.AddTypeRef(D->getPromotionType());
429   Record.push_back(D->getNumPositiveBits());
430   Record.push_back(D->getNumNegativeBits());
431   Record.push_back(D->isScoped());
432   Record.push_back(D->isScopedUsingClassTag());
433   Record.push_back(D->isFixed());
434   if (MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo()) {
435     Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
436     Record.push_back(MemberInfo->getTemplateSpecializationKind());
437     Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
438   } else {
439     Record.AddDeclRef(nullptr);
440   }
441 
442   if (D->getDeclContext() == D->getLexicalDeclContext() &&
443       !D->hasAttrs() &&
444       !D->isImplicit() &&
445       !D->isUsed(false) &&
446       !D->hasExtInfo() &&
447       !D->getTypedefNameForAnonDecl() &&
448       D->getFirstDecl() == D->getMostRecentDecl() &&
449       !D->isInvalidDecl() &&
450       !D->isReferenced() &&
451       !D->isTopLevelDeclInObjCContainer() &&
452       D->getAccess() == AS_none &&
453       !D->isModulePrivate() &&
454       !CXXRecordDecl::classofKind(D->getKind()) &&
455       !D->getIntegerTypeSourceInfo() &&
456       !D->getMemberSpecializationInfo() &&
457       !needsAnonymousDeclarationNumber(D) &&
458       D->getDeclName().getNameKind() == DeclarationName::Identifier)
459     AbbrevToUse = Writer.getDeclEnumAbbrev();
460 
461   Code = serialization::DECL_ENUM;
462 }
463 
464 void ASTDeclWriter::VisitRecordDecl(RecordDecl *D) {
465   VisitTagDecl(D);
466   Record.push_back(D->hasFlexibleArrayMember());
467   Record.push_back(D->isAnonymousStructOrUnion());
468   Record.push_back(D->hasObjectMember());
469   Record.push_back(D->hasVolatileMember());
470   Record.push_back(D->isNonTrivialToPrimitiveDefaultInitialize());
471   Record.push_back(D->isNonTrivialToPrimitiveCopy());
472   Record.push_back(D->isNonTrivialToPrimitiveDestroy());
473   Record.push_back(D->isParamDestroyedInCallee());
474   Record.push_back(D->getArgPassingRestrictions());
475 
476   if (D->getDeclContext() == D->getLexicalDeclContext() &&
477       !D->hasAttrs() &&
478       !D->isImplicit() &&
479       !D->isUsed(false) &&
480       !D->hasExtInfo() &&
481       !D->getTypedefNameForAnonDecl() &&
482       D->getFirstDecl() == D->getMostRecentDecl() &&
483       !D->isInvalidDecl() &&
484       !D->isReferenced() &&
485       !D->isTopLevelDeclInObjCContainer() &&
486       D->getAccess() == AS_none &&
487       !D->isModulePrivate() &&
488       !CXXRecordDecl::classofKind(D->getKind()) &&
489       !needsAnonymousDeclarationNumber(D) &&
490       D->getDeclName().getNameKind() == DeclarationName::Identifier)
491     AbbrevToUse = Writer.getDeclRecordAbbrev();
492 
493   Code = serialization::DECL_RECORD;
494 }
495 
496 void ASTDeclWriter::VisitValueDecl(ValueDecl *D) {
497   VisitNamedDecl(D);
498   Record.AddTypeRef(D->getType());
499 }
500 
501 void ASTDeclWriter::VisitEnumConstantDecl(EnumConstantDecl *D) {
502   VisitValueDecl(D);
503   Record.push_back(D->getInitExpr()? 1 : 0);
504   if (D->getInitExpr())
505     Record.AddStmt(D->getInitExpr());
506   Record.AddAPSInt(D->getInitVal());
507 
508   Code = serialization::DECL_ENUM_CONSTANT;
509 }
510 
511 void ASTDeclWriter::VisitDeclaratorDecl(DeclaratorDecl *D) {
512   VisitValueDecl(D);
513   Record.AddSourceLocation(D->getInnerLocStart());
514   Record.push_back(D->hasExtInfo());
515   if (D->hasExtInfo())
516     Record.AddQualifierInfo(*D->getExtInfo());
517   // The location information is deferred until the end of the record.
518   Record.AddTypeRef(D->getTypeSourceInfo() ? D->getTypeSourceInfo()->getType()
519                                            : QualType());
520 }
521 
522 void ASTDeclWriter::VisitFunctionDecl(FunctionDecl *D) {
523   VisitRedeclarable(D);
524   VisitDeclaratorDecl(D);
525   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
526   Record.push_back(D->getIdentifierNamespace());
527 
528   // FunctionDecl's body is handled last at ASTWriterDecl::Visit,
529   // after everything else is written.
530 
531   Record.push_back((int)D->SClass); // FIXME: stable encoding
532   Record.push_back(D->IsInline);
533   Record.push_back(D->IsInlineSpecified);
534   Record.push_back(D->IsExplicitSpecified);
535   Record.push_back(D->IsVirtualAsWritten);
536   Record.push_back(D->IsPure);
537   Record.push_back(D->HasInheritedPrototype);
538   Record.push_back(D->HasWrittenPrototype);
539   Record.push_back(D->IsDeleted);
540   Record.push_back(D->IsTrivial);
541   Record.push_back(D->IsTrivialForCall);
542   Record.push_back(D->IsDefaulted);
543   Record.push_back(D->IsExplicitlyDefaulted);
544   Record.push_back(D->HasImplicitReturnZero);
545   Record.push_back(D->IsConstexpr);
546   Record.push_back(D->UsesSEHTry);
547   Record.push_back(D->HasSkippedBody);
548   Record.push_back(D->IsMultiVersion);
549   Record.push_back(D->IsLateTemplateParsed);
550   Record.push_back(D->getLinkageInternal());
551   Record.AddSourceLocation(D->getLocEnd());
552 
553   Record.push_back(D->getODRHash());
554 
555   Record.push_back(D->getTemplatedKind());
556   switch (D->getTemplatedKind()) {
557   case FunctionDecl::TK_NonTemplate:
558     break;
559   case FunctionDecl::TK_FunctionTemplate:
560     Record.AddDeclRef(D->getDescribedFunctionTemplate());
561     break;
562   case FunctionDecl::TK_MemberSpecialization: {
563     MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo();
564     Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
565     Record.push_back(MemberInfo->getTemplateSpecializationKind());
566     Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
567     break;
568   }
569   case FunctionDecl::TK_FunctionTemplateSpecialization: {
570     FunctionTemplateSpecializationInfo *
571       FTSInfo = D->getTemplateSpecializationInfo();
572 
573     RegisterTemplateSpecialization(FTSInfo->getTemplate(), D);
574 
575     Record.AddDeclRef(FTSInfo->getTemplate());
576     Record.push_back(FTSInfo->getTemplateSpecializationKind());
577 
578     // Template arguments.
579     Record.AddTemplateArgumentList(FTSInfo->TemplateArguments);
580 
581     // Template args as written.
582     Record.push_back(FTSInfo->TemplateArgumentsAsWritten != nullptr);
583     if (FTSInfo->TemplateArgumentsAsWritten) {
584       Record.push_back(FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs);
585       for (int i=0, e = FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs;
586              i!=e; ++i)
587         Record.AddTemplateArgumentLoc(
588             (*FTSInfo->TemplateArgumentsAsWritten)[i]);
589       Record.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->LAngleLoc);
590       Record.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->RAngleLoc);
591     }
592 
593     Record.AddSourceLocation(FTSInfo->getPointOfInstantiation());
594 
595     if (D->isCanonicalDecl()) {
596       // Write the template that contains the specializations set. We will
597       // add a FunctionTemplateSpecializationInfo to it when reading.
598       Record.AddDeclRef(FTSInfo->getTemplate()->getCanonicalDecl());
599     }
600     break;
601   }
602   case FunctionDecl::TK_DependentFunctionTemplateSpecialization: {
603     DependentFunctionTemplateSpecializationInfo *
604       DFTSInfo = D->getDependentSpecializationInfo();
605 
606     // Templates.
607     Record.push_back(DFTSInfo->getNumTemplates());
608     for (int i=0, e = DFTSInfo->getNumTemplates(); i != e; ++i)
609       Record.AddDeclRef(DFTSInfo->getTemplate(i));
610 
611     // Templates args.
612     Record.push_back(DFTSInfo->getNumTemplateArgs());
613     for (int i=0, e = DFTSInfo->getNumTemplateArgs(); i != e; ++i)
614       Record.AddTemplateArgumentLoc(DFTSInfo->getTemplateArg(i));
615     Record.AddSourceLocation(DFTSInfo->getLAngleLoc());
616     Record.AddSourceLocation(DFTSInfo->getRAngleLoc());
617     break;
618   }
619   }
620 
621   Record.push_back(D->param_size());
622   for (auto P : D->parameters())
623     Record.AddDeclRef(P);
624   Code = serialization::DECL_FUNCTION;
625 }
626 
627 void ASTDeclWriter::VisitCXXDeductionGuideDecl(CXXDeductionGuideDecl *D) {
628   VisitFunctionDecl(D);
629   Record.push_back(D->IsCopyDeductionCandidate);
630   Code = serialization::DECL_CXX_DEDUCTION_GUIDE;
631 }
632 
633 void ASTDeclWriter::VisitObjCMethodDecl(ObjCMethodDecl *D) {
634   VisitNamedDecl(D);
635   // FIXME: convert to LazyStmtPtr?
636   // Unlike C/C++, method bodies will never be in header files.
637   bool HasBodyStuff = D->getBody() != nullptr     ||
638                       D->getSelfDecl() != nullptr || D->getCmdDecl() != nullptr;
639   Record.push_back(HasBodyStuff);
640   if (HasBodyStuff) {
641     Record.AddStmt(D->getBody());
642     Record.AddDeclRef(D->getSelfDecl());
643     Record.AddDeclRef(D->getCmdDecl());
644   }
645   Record.push_back(D->isInstanceMethod());
646   Record.push_back(D->isVariadic());
647   Record.push_back(D->isPropertyAccessor());
648   Record.push_back(D->isDefined());
649   Record.push_back(D->IsOverriding);
650   Record.push_back(D->HasSkippedBody);
651 
652   Record.push_back(D->IsRedeclaration);
653   Record.push_back(D->HasRedeclaration);
654   if (D->HasRedeclaration) {
655     assert(Context.getObjCMethodRedeclaration(D));
656     Record.AddDeclRef(Context.getObjCMethodRedeclaration(D));
657   }
658 
659   // FIXME: stable encoding for @required/@optional
660   Record.push_back(D->getImplementationControl());
661   // FIXME: stable encoding for in/out/inout/bycopy/byref/oneway/nullability
662   Record.push_back(D->getObjCDeclQualifier());
663   Record.push_back(D->hasRelatedResultType());
664   Record.AddTypeRef(D->getReturnType());
665   Record.AddTypeSourceInfo(D->getReturnTypeSourceInfo());
666   Record.AddSourceLocation(D->getLocEnd());
667   Record.push_back(D->param_size());
668   for (const auto *P : D->parameters())
669     Record.AddDeclRef(P);
670 
671   Record.push_back(D->SelLocsKind);
672   unsigned NumStoredSelLocs = D->getNumStoredSelLocs();
673   SourceLocation *SelLocs = D->getStoredSelLocs();
674   Record.push_back(NumStoredSelLocs);
675   for (unsigned i = 0; i != NumStoredSelLocs; ++i)
676     Record.AddSourceLocation(SelLocs[i]);
677 
678   Code = serialization::DECL_OBJC_METHOD;
679 }
680 
681 void ASTDeclWriter::VisitObjCTypeParamDecl(ObjCTypeParamDecl *D) {
682   VisitTypedefNameDecl(D);
683   Record.push_back(D->Variance);
684   Record.push_back(D->Index);
685   Record.AddSourceLocation(D->VarianceLoc);
686   Record.AddSourceLocation(D->ColonLoc);
687 
688   Code = serialization::DECL_OBJC_TYPE_PARAM;
689 }
690 
691 void ASTDeclWriter::VisitObjCContainerDecl(ObjCContainerDecl *D) {
692   VisitNamedDecl(D);
693   Record.AddSourceLocation(D->getAtStartLoc());
694   Record.AddSourceRange(D->getAtEndRange());
695   // Abstract class (no need to define a stable serialization::DECL code).
696 }
697 
698 void ASTDeclWriter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
699   VisitRedeclarable(D);
700   VisitObjCContainerDecl(D);
701   Record.AddTypeRef(QualType(D->getTypeForDecl(), 0));
702   AddObjCTypeParamList(D->TypeParamList);
703 
704   Record.push_back(D->isThisDeclarationADefinition());
705   if (D->isThisDeclarationADefinition()) {
706     // Write the DefinitionData
707     ObjCInterfaceDecl::DefinitionData &Data = D->data();
708 
709     Record.AddTypeSourceInfo(D->getSuperClassTInfo());
710     Record.AddSourceLocation(D->getEndOfDefinitionLoc());
711     Record.push_back(Data.HasDesignatedInitializers);
712 
713     // Write out the protocols that are directly referenced by the @interface.
714     Record.push_back(Data.ReferencedProtocols.size());
715     for (const auto *P : D->protocols())
716       Record.AddDeclRef(P);
717     for (const auto &PL : D->protocol_locs())
718       Record.AddSourceLocation(PL);
719 
720     // Write out the protocols that are transitively referenced.
721     Record.push_back(Data.AllReferencedProtocols.size());
722     for (ObjCList<ObjCProtocolDecl>::iterator
723               P = Data.AllReferencedProtocols.begin(),
724            PEnd = Data.AllReferencedProtocols.end();
725          P != PEnd; ++P)
726       Record.AddDeclRef(*P);
727 
728 
729     if (ObjCCategoryDecl *Cat = D->getCategoryListRaw()) {
730       // Ensure that we write out the set of categories for this class.
731       Writer.ObjCClassesWithCategories.insert(D);
732 
733       // Make sure that the categories get serialized.
734       for (; Cat; Cat = Cat->getNextClassCategoryRaw())
735         (void)Writer.GetDeclRef(Cat);
736     }
737   }
738 
739   Code = serialization::DECL_OBJC_INTERFACE;
740 }
741 
742 void ASTDeclWriter::VisitObjCIvarDecl(ObjCIvarDecl *D) {
743   VisitFieldDecl(D);
744   // FIXME: stable encoding for @public/@private/@protected/@package
745   Record.push_back(D->getAccessControl());
746   Record.push_back(D->getSynthesize());
747 
748   if (D->getDeclContext() == D->getLexicalDeclContext() &&
749       !D->hasAttrs() &&
750       !D->isImplicit() &&
751       !D->isUsed(false) &&
752       !D->isInvalidDecl() &&
753       !D->isReferenced() &&
754       !D->isModulePrivate() &&
755       !D->getBitWidth() &&
756       !D->hasExtInfo() &&
757       D->getDeclName())
758     AbbrevToUse = Writer.getDeclObjCIvarAbbrev();
759 
760   Code = serialization::DECL_OBJC_IVAR;
761 }
762 
763 void ASTDeclWriter::VisitObjCProtocolDecl(ObjCProtocolDecl *D) {
764   VisitRedeclarable(D);
765   VisitObjCContainerDecl(D);
766 
767   Record.push_back(D->isThisDeclarationADefinition());
768   if (D->isThisDeclarationADefinition()) {
769     Record.push_back(D->protocol_size());
770     for (const auto *I : D->protocols())
771       Record.AddDeclRef(I);
772     for (const auto &PL : D->protocol_locs())
773       Record.AddSourceLocation(PL);
774   }
775 
776   Code = serialization::DECL_OBJC_PROTOCOL;
777 }
778 
779 void ASTDeclWriter::VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D) {
780   VisitFieldDecl(D);
781   Code = serialization::DECL_OBJC_AT_DEFS_FIELD;
782 }
783 
784 void ASTDeclWriter::VisitObjCCategoryDecl(ObjCCategoryDecl *D) {
785   VisitObjCContainerDecl(D);
786   Record.AddSourceLocation(D->getCategoryNameLoc());
787   Record.AddSourceLocation(D->getIvarLBraceLoc());
788   Record.AddSourceLocation(D->getIvarRBraceLoc());
789   Record.AddDeclRef(D->getClassInterface());
790   AddObjCTypeParamList(D->TypeParamList);
791   Record.push_back(D->protocol_size());
792   for (const auto *I : D->protocols())
793     Record.AddDeclRef(I);
794   for (const auto &PL : D->protocol_locs())
795     Record.AddSourceLocation(PL);
796   Code = serialization::DECL_OBJC_CATEGORY;
797 }
798 
799 void ASTDeclWriter::VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D) {
800   VisitNamedDecl(D);
801   Record.AddDeclRef(D->getClassInterface());
802   Code = serialization::DECL_OBJC_COMPATIBLE_ALIAS;
803 }
804 
805 void ASTDeclWriter::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
806   VisitNamedDecl(D);
807   Record.AddSourceLocation(D->getAtLoc());
808   Record.AddSourceLocation(D->getLParenLoc());
809   Record.AddTypeRef(D->getType());
810   Record.AddTypeSourceInfo(D->getTypeSourceInfo());
811   // FIXME: stable encoding
812   Record.push_back((unsigned)D->getPropertyAttributes());
813   Record.push_back((unsigned)D->getPropertyAttributesAsWritten());
814   // FIXME: stable encoding
815   Record.push_back((unsigned)D->getPropertyImplementation());
816   Record.AddDeclarationName(D->getGetterName());
817   Record.AddSourceLocation(D->getGetterNameLoc());
818   Record.AddDeclarationName(D->getSetterName());
819   Record.AddSourceLocation(D->getSetterNameLoc());
820   Record.AddDeclRef(D->getGetterMethodDecl());
821   Record.AddDeclRef(D->getSetterMethodDecl());
822   Record.AddDeclRef(D->getPropertyIvarDecl());
823   Code = serialization::DECL_OBJC_PROPERTY;
824 }
825 
826 void ASTDeclWriter::VisitObjCImplDecl(ObjCImplDecl *D) {
827   VisitObjCContainerDecl(D);
828   Record.AddDeclRef(D->getClassInterface());
829   // Abstract class (no need to define a stable serialization::DECL code).
830 }
831 
832 void ASTDeclWriter::VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D) {
833   VisitObjCImplDecl(D);
834   Record.AddSourceLocation(D->getCategoryNameLoc());
835   Code = serialization::DECL_OBJC_CATEGORY_IMPL;
836 }
837 
838 void ASTDeclWriter::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
839   VisitObjCImplDecl(D);
840   Record.AddDeclRef(D->getSuperClass());
841   Record.AddSourceLocation(D->getSuperClassLoc());
842   Record.AddSourceLocation(D->getIvarLBraceLoc());
843   Record.AddSourceLocation(D->getIvarRBraceLoc());
844   Record.push_back(D->hasNonZeroConstructors());
845   Record.push_back(D->hasDestructors());
846   Record.push_back(D->NumIvarInitializers);
847   if (D->NumIvarInitializers)
848     Record.AddCXXCtorInitializers(
849         llvm::makeArrayRef(D->init_begin(), D->init_end()));
850   Code = serialization::DECL_OBJC_IMPLEMENTATION;
851 }
852 
853 void ASTDeclWriter::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
854   VisitDecl(D);
855   Record.AddSourceLocation(D->getLocStart());
856   Record.AddDeclRef(D->getPropertyDecl());
857   Record.AddDeclRef(D->getPropertyIvarDecl());
858   Record.AddSourceLocation(D->getPropertyIvarDeclLoc());
859   Record.AddStmt(D->getGetterCXXConstructor());
860   Record.AddStmt(D->getSetterCXXAssignment());
861   Code = serialization::DECL_OBJC_PROPERTY_IMPL;
862 }
863 
864 void ASTDeclWriter::VisitFieldDecl(FieldDecl *D) {
865   VisitDeclaratorDecl(D);
866   Record.push_back(D->isMutable());
867 
868   FieldDecl::InitStorageKind ISK = D->InitStorage.getInt();
869   Record.push_back(ISK);
870   if (ISK == FieldDecl::ISK_CapturedVLAType)
871     Record.AddTypeRef(QualType(D->getCapturedVLAType(), 0));
872   else if (ISK)
873     Record.AddStmt(D->getInClassInitializer());
874 
875   Record.AddStmt(D->getBitWidth());
876 
877   if (!D->getDeclName())
878     Record.AddDeclRef(Context.getInstantiatedFromUnnamedFieldDecl(D));
879 
880   if (D->getDeclContext() == D->getLexicalDeclContext() &&
881       !D->hasAttrs() &&
882       !D->isImplicit() &&
883       !D->isUsed(false) &&
884       !D->isInvalidDecl() &&
885       !D->isReferenced() &&
886       !D->isTopLevelDeclInObjCContainer() &&
887       !D->isModulePrivate() &&
888       !D->getBitWidth() &&
889       !D->hasInClassInitializer() &&
890       !D->hasCapturedVLAType() &&
891       !D->hasExtInfo() &&
892       !ObjCIvarDecl::classofKind(D->getKind()) &&
893       !ObjCAtDefsFieldDecl::classofKind(D->getKind()) &&
894       D->getDeclName())
895     AbbrevToUse = Writer.getDeclFieldAbbrev();
896 
897   Code = serialization::DECL_FIELD;
898 }
899 
900 void ASTDeclWriter::VisitMSPropertyDecl(MSPropertyDecl *D) {
901   VisitDeclaratorDecl(D);
902   Record.AddIdentifierRef(D->getGetterId());
903   Record.AddIdentifierRef(D->getSetterId());
904   Code = serialization::DECL_MS_PROPERTY;
905 }
906 
907 void ASTDeclWriter::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
908   VisitValueDecl(D);
909   Record.push_back(D->getChainingSize());
910 
911   for (const auto *P : D->chain())
912     Record.AddDeclRef(P);
913   Code = serialization::DECL_INDIRECTFIELD;
914 }
915 
916 void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
917   VisitRedeclarable(D);
918   VisitDeclaratorDecl(D);
919   Record.push_back(D->getStorageClass());
920   Record.push_back(D->getTSCSpec());
921   Record.push_back(D->getInitStyle());
922   if (!isa<ParmVarDecl>(D)) {
923     Record.push_back(D->isThisDeclarationADemotedDefinition());
924     Record.push_back(D->isExceptionVariable());
925     Record.push_back(D->isNRVOVariable());
926     Record.push_back(D->isCXXForRangeDecl());
927     Record.push_back(D->isObjCForDecl());
928     Record.push_back(D->isARCPseudoStrong());
929     Record.push_back(D->isInline());
930     Record.push_back(D->isInlineSpecified());
931     Record.push_back(D->isConstexpr());
932     Record.push_back(D->isInitCapture());
933     Record.push_back(D->isPreviousDeclInSameBlockScope());
934     if (const auto *IPD = dyn_cast<ImplicitParamDecl>(D))
935       Record.push_back(static_cast<unsigned>(IPD->getParameterKind()));
936     else
937       Record.push_back(0);
938   }
939   Record.push_back(D->getLinkageInternal());
940 
941   if (D->getInit()) {
942     Record.push_back(!D->isInitKnownICE() ? 1 : (D->isInitICE() ? 3 : 2));
943     Record.AddStmt(D->getInit());
944   } else {
945     Record.push_back(0);
946   }
947 
948   if (D->getStorageDuration() == SD_Static) {
949     bool ModulesCodegen = false;
950     if (Writer.WritingModule &&
951         !D->getDescribedVarTemplate() && !D->getMemberSpecializationInfo() &&
952         !isa<VarTemplateSpecializationDecl>(D)) {
953       // When building a C++ Modules TS module interface unit, a strong
954       // definition in the module interface is provided by the compilation of
955       // that module interface unit, not by its users. (Inline variables are
956       // still emitted in module users.)
957       ModulesCodegen =
958           (Writer.WritingModule->Kind == Module::ModuleInterfaceUnit &&
959            Writer.Context->GetGVALinkageForVariable(D) == GVA_StrongExternal);
960     }
961     Record.push_back(ModulesCodegen);
962     if (ModulesCodegen)
963       Writer.ModularCodegenDecls.push_back(Writer.GetDeclRef(D));
964   }
965 
966   enum {
967     VarNotTemplate = 0, VarTemplate, StaticDataMemberSpecialization
968   };
969   if (VarTemplateDecl *TemplD = D->getDescribedVarTemplate()) {
970     Record.push_back(VarTemplate);
971     Record.AddDeclRef(TemplD);
972   } else if (MemberSpecializationInfo *SpecInfo
973                = D->getMemberSpecializationInfo()) {
974     Record.push_back(StaticDataMemberSpecialization);
975     Record.AddDeclRef(SpecInfo->getInstantiatedFrom());
976     Record.push_back(SpecInfo->getTemplateSpecializationKind());
977     Record.AddSourceLocation(SpecInfo->getPointOfInstantiation());
978   } else {
979     Record.push_back(VarNotTemplate);
980   }
981 
982   if (D->getDeclContext() == D->getLexicalDeclContext() &&
983       !D->hasAttrs() &&
984       !D->isImplicit() &&
985       !D->isUsed(false) &&
986       !D->isInvalidDecl() &&
987       !D->isReferenced() &&
988       !D->isTopLevelDeclInObjCContainer() &&
989       D->getAccess() == AS_none &&
990       !D->isModulePrivate() &&
991       !needsAnonymousDeclarationNumber(D) &&
992       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
993       !D->hasExtInfo() &&
994       D->getFirstDecl() == D->getMostRecentDecl() &&
995       D->getKind() == Decl::Var &&
996       !D->isInline() &&
997       !D->isConstexpr() &&
998       !D->isInitCapture() &&
999       !D->isPreviousDeclInSameBlockScope() &&
1000       D->getStorageDuration() != SD_Static &&
1001       !D->getMemberSpecializationInfo())
1002     AbbrevToUse = Writer.getDeclVarAbbrev();
1003 
1004   Code = serialization::DECL_VAR;
1005 }
1006 
1007 void ASTDeclWriter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
1008   VisitVarDecl(D);
1009   Code = serialization::DECL_IMPLICIT_PARAM;
1010 }
1011 
1012 void ASTDeclWriter::VisitParmVarDecl(ParmVarDecl *D) {
1013   VisitVarDecl(D);
1014   Record.push_back(D->isObjCMethodParameter());
1015   Record.push_back(D->getFunctionScopeDepth());
1016   Record.push_back(D->getFunctionScopeIndex());
1017   Record.push_back(D->getObjCDeclQualifier()); // FIXME: stable encoding
1018   Record.push_back(D->isKNRPromoted());
1019   Record.push_back(D->hasInheritedDefaultArg());
1020   Record.push_back(D->hasUninstantiatedDefaultArg());
1021   if (D->hasUninstantiatedDefaultArg())
1022     Record.AddStmt(D->getUninstantiatedDefaultArg());
1023   Code = serialization::DECL_PARM_VAR;
1024 
1025   assert(!D->isARCPseudoStrong()); // can be true of ImplicitParamDecl
1026 
1027   // If the assumptions about the DECL_PARM_VAR abbrev are true, use it.  Here
1028   // we dynamically check for the properties that we optimize for, but don't
1029   // know are true of all PARM_VAR_DECLs.
1030   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1031       !D->hasAttrs() &&
1032       !D->hasExtInfo() &&
1033       !D->isImplicit() &&
1034       !D->isUsed(false) &&
1035       !D->isInvalidDecl() &&
1036       !D->isReferenced() &&
1037       D->getAccess() == AS_none &&
1038       !D->isModulePrivate() &&
1039       D->getStorageClass() == 0 &&
1040       D->getInitStyle() == VarDecl::CInit && // Can params have anything else?
1041       D->getFunctionScopeDepth() == 0 &&
1042       D->getObjCDeclQualifier() == 0 &&
1043       !D->isKNRPromoted() &&
1044       !D->hasInheritedDefaultArg() &&
1045       D->getInit() == nullptr &&
1046       !D->hasUninstantiatedDefaultArg())  // No default expr.
1047     AbbrevToUse = Writer.getDeclParmVarAbbrev();
1048 
1049   // Check things we know are true of *every* PARM_VAR_DECL, which is more than
1050   // just us assuming it.
1051   assert(!D->getTSCSpec() && "PARM_VAR_DECL can't use TLS");
1052   assert(!D->isThisDeclarationADemotedDefinition()
1053          && "PARM_VAR_DECL can't be demoted definition.");
1054   assert(D->getAccess() == AS_none && "PARM_VAR_DECL can't be public/private");
1055   assert(!D->isExceptionVariable() && "PARM_VAR_DECL can't be exception var");
1056   assert(D->getPreviousDecl() == nullptr && "PARM_VAR_DECL can't be redecl");
1057   assert(!D->isStaticDataMember() &&
1058          "PARM_VAR_DECL can't be static data member");
1059 }
1060 
1061 void ASTDeclWriter::VisitDecompositionDecl(DecompositionDecl *D) {
1062   // Record the number of bindings first to simplify deserialization.
1063   Record.push_back(D->bindings().size());
1064 
1065   VisitVarDecl(D);
1066   for (auto *B : D->bindings())
1067     Record.AddDeclRef(B);
1068   Code = serialization::DECL_DECOMPOSITION;
1069 }
1070 
1071 void ASTDeclWriter::VisitBindingDecl(BindingDecl *D) {
1072   VisitValueDecl(D);
1073   Record.AddStmt(D->getBinding());
1074   Code = serialization::DECL_BINDING;
1075 }
1076 
1077 void ASTDeclWriter::VisitFileScopeAsmDecl(FileScopeAsmDecl *D) {
1078   VisitDecl(D);
1079   Record.AddStmt(D->getAsmString());
1080   Record.AddSourceLocation(D->getRParenLoc());
1081   Code = serialization::DECL_FILE_SCOPE_ASM;
1082 }
1083 
1084 void ASTDeclWriter::VisitEmptyDecl(EmptyDecl *D) {
1085   VisitDecl(D);
1086   Code = serialization::DECL_EMPTY;
1087 }
1088 
1089 void ASTDeclWriter::VisitBlockDecl(BlockDecl *D) {
1090   VisitDecl(D);
1091   Record.AddStmt(D->getBody());
1092   Record.AddTypeSourceInfo(D->getSignatureAsWritten());
1093   Record.push_back(D->param_size());
1094   for (ParmVarDecl *P : D->parameters())
1095     Record.AddDeclRef(P);
1096   Record.push_back(D->isVariadic());
1097   Record.push_back(D->blockMissingReturnType());
1098   Record.push_back(D->isConversionFromLambda());
1099   Record.push_back(D->capturesCXXThis());
1100   Record.push_back(D->getNumCaptures());
1101   for (const auto &capture : D->captures()) {
1102     Record.AddDeclRef(capture.getVariable());
1103 
1104     unsigned flags = 0;
1105     if (capture.isByRef()) flags |= 1;
1106     if (capture.isNested()) flags |= 2;
1107     if (capture.hasCopyExpr()) flags |= 4;
1108     Record.push_back(flags);
1109 
1110     if (capture.hasCopyExpr()) Record.AddStmt(capture.getCopyExpr());
1111   }
1112 
1113   Code = serialization::DECL_BLOCK;
1114 }
1115 
1116 void ASTDeclWriter::VisitCapturedDecl(CapturedDecl *CD) {
1117   Record.push_back(CD->getNumParams());
1118   VisitDecl(CD);
1119   Record.push_back(CD->getContextParamPosition());
1120   Record.push_back(CD->isNothrow() ? 1 : 0);
1121   // Body is stored by VisitCapturedStmt.
1122   for (unsigned I = 0; I < CD->getNumParams(); ++I)
1123     Record.AddDeclRef(CD->getParam(I));
1124   Code = serialization::DECL_CAPTURED;
1125 }
1126 
1127 void ASTDeclWriter::VisitLinkageSpecDecl(LinkageSpecDecl *D) {
1128   VisitDecl(D);
1129   Record.push_back(D->getLanguage());
1130   Record.AddSourceLocation(D->getExternLoc());
1131   Record.AddSourceLocation(D->getRBraceLoc());
1132   Code = serialization::DECL_LINKAGE_SPEC;
1133 }
1134 
1135 void ASTDeclWriter::VisitExportDecl(ExportDecl *D) {
1136   VisitDecl(D);
1137   Record.AddSourceLocation(D->getRBraceLoc());
1138   Code = serialization::DECL_EXPORT;
1139 }
1140 
1141 void ASTDeclWriter::VisitLabelDecl(LabelDecl *D) {
1142   VisitNamedDecl(D);
1143   Record.AddSourceLocation(D->getLocStart());
1144   Code = serialization::DECL_LABEL;
1145 }
1146 
1147 
1148 void ASTDeclWriter::VisitNamespaceDecl(NamespaceDecl *D) {
1149   VisitRedeclarable(D);
1150   VisitNamedDecl(D);
1151   Record.push_back(D->isInline());
1152   Record.AddSourceLocation(D->getLocStart());
1153   Record.AddSourceLocation(D->getRBraceLoc());
1154 
1155   if (D->isOriginalNamespace())
1156     Record.AddDeclRef(D->getAnonymousNamespace());
1157   Code = serialization::DECL_NAMESPACE;
1158 
1159   if (Writer.hasChain() && D->isAnonymousNamespace() &&
1160       D == D->getMostRecentDecl()) {
1161     // This is a most recent reopening of the anonymous namespace. If its parent
1162     // is in a previous PCH (or is the TU), mark that parent for update, because
1163     // the original namespace always points to the latest re-opening of its
1164     // anonymous namespace.
1165     Decl *Parent = cast<Decl>(
1166         D->getParent()->getRedeclContext()->getPrimaryContext());
1167     if (Parent->isFromASTFile() || isa<TranslationUnitDecl>(Parent)) {
1168       Writer.DeclUpdates[Parent].push_back(
1169           ASTWriter::DeclUpdate(UPD_CXX_ADDED_ANONYMOUS_NAMESPACE, D));
1170     }
1171   }
1172 }
1173 
1174 void ASTDeclWriter::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
1175   VisitRedeclarable(D);
1176   VisitNamedDecl(D);
1177   Record.AddSourceLocation(D->getNamespaceLoc());
1178   Record.AddSourceLocation(D->getTargetNameLoc());
1179   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1180   Record.AddDeclRef(D->getNamespace());
1181   Code = serialization::DECL_NAMESPACE_ALIAS;
1182 }
1183 
1184 void ASTDeclWriter::VisitUsingDecl(UsingDecl *D) {
1185   VisitNamedDecl(D);
1186   Record.AddSourceLocation(D->getUsingLoc());
1187   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1188   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
1189   Record.AddDeclRef(D->FirstUsingShadow.getPointer());
1190   Record.push_back(D->hasTypename());
1191   Record.AddDeclRef(Context.getInstantiatedFromUsingDecl(D));
1192   Code = serialization::DECL_USING;
1193 }
1194 
1195 void ASTDeclWriter::VisitUsingPackDecl(UsingPackDecl *D) {
1196   Record.push_back(D->NumExpansions);
1197   VisitNamedDecl(D);
1198   Record.AddDeclRef(D->getInstantiatedFromUsingDecl());
1199   for (auto *E : D->expansions())
1200     Record.AddDeclRef(E);
1201   Code = serialization::DECL_USING_PACK;
1202 }
1203 
1204 void ASTDeclWriter::VisitUsingShadowDecl(UsingShadowDecl *D) {
1205   VisitRedeclarable(D);
1206   VisitNamedDecl(D);
1207   Record.AddDeclRef(D->getTargetDecl());
1208   Record.push_back(D->getIdentifierNamespace());
1209   Record.AddDeclRef(D->UsingOrNextShadow);
1210   Record.AddDeclRef(Context.getInstantiatedFromUsingShadowDecl(D));
1211   Code = serialization::DECL_USING_SHADOW;
1212 }
1213 
1214 void ASTDeclWriter::VisitConstructorUsingShadowDecl(
1215     ConstructorUsingShadowDecl *D) {
1216   VisitUsingShadowDecl(D);
1217   Record.AddDeclRef(D->NominatedBaseClassShadowDecl);
1218   Record.AddDeclRef(D->ConstructedBaseClassShadowDecl);
1219   Record.push_back(D->IsVirtual);
1220   Code = serialization::DECL_CONSTRUCTOR_USING_SHADOW;
1221 }
1222 
1223 void ASTDeclWriter::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1224   VisitNamedDecl(D);
1225   Record.AddSourceLocation(D->getUsingLoc());
1226   Record.AddSourceLocation(D->getNamespaceKeyLocation());
1227   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1228   Record.AddDeclRef(D->getNominatedNamespace());
1229   Record.AddDeclRef(dyn_cast<Decl>(D->getCommonAncestor()));
1230   Code = serialization::DECL_USING_DIRECTIVE;
1231 }
1232 
1233 void ASTDeclWriter::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1234   VisitValueDecl(D);
1235   Record.AddSourceLocation(D->getUsingLoc());
1236   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1237   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
1238   Record.AddSourceLocation(D->getEllipsisLoc());
1239   Code = serialization::DECL_UNRESOLVED_USING_VALUE;
1240 }
1241 
1242 void ASTDeclWriter::VisitUnresolvedUsingTypenameDecl(
1243                                                UnresolvedUsingTypenameDecl *D) {
1244   VisitTypeDecl(D);
1245   Record.AddSourceLocation(D->getTypenameLoc());
1246   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1247   Record.AddSourceLocation(D->getEllipsisLoc());
1248   Code = serialization::DECL_UNRESOLVED_USING_TYPENAME;
1249 }
1250 
1251 void ASTDeclWriter::VisitCXXRecordDecl(CXXRecordDecl *D) {
1252   VisitRecordDecl(D);
1253 
1254   enum {
1255     CXXRecNotTemplate = 0, CXXRecTemplate, CXXRecMemberSpecialization
1256   };
1257   if (ClassTemplateDecl *TemplD = D->getDescribedClassTemplate()) {
1258     Record.push_back(CXXRecTemplate);
1259     Record.AddDeclRef(TemplD);
1260   } else if (MemberSpecializationInfo *MSInfo
1261                = D->getMemberSpecializationInfo()) {
1262     Record.push_back(CXXRecMemberSpecialization);
1263     Record.AddDeclRef(MSInfo->getInstantiatedFrom());
1264     Record.push_back(MSInfo->getTemplateSpecializationKind());
1265     Record.AddSourceLocation(MSInfo->getPointOfInstantiation());
1266   } else {
1267     Record.push_back(CXXRecNotTemplate);
1268   }
1269 
1270   Record.push_back(D->isThisDeclarationADefinition());
1271   if (D->isThisDeclarationADefinition())
1272     Record.AddCXXDefinitionData(D);
1273 
1274   // Store (what we currently believe to be) the key function to avoid
1275   // deserializing every method so we can compute it.
1276   if (D->IsCompleteDefinition)
1277     Record.AddDeclRef(Context.getCurrentKeyFunction(D));
1278 
1279   Code = serialization::DECL_CXX_RECORD;
1280 }
1281 
1282 void ASTDeclWriter::VisitCXXMethodDecl(CXXMethodDecl *D) {
1283   VisitFunctionDecl(D);
1284   if (D->isCanonicalDecl()) {
1285     Record.push_back(D->size_overridden_methods());
1286     for (const CXXMethodDecl *MD : D->overridden_methods())
1287       Record.AddDeclRef(MD);
1288   } else {
1289     // We only need to record overridden methods once for the canonical decl.
1290     Record.push_back(0);
1291   }
1292 
1293   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1294       D->getFirstDecl() == D->getMostRecentDecl() &&
1295       !D->isInvalidDecl() &&
1296       !D->hasAttrs() &&
1297       !D->isTopLevelDeclInObjCContainer() &&
1298       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1299       !D->hasExtInfo() &&
1300       !D->hasInheritedPrototype() &&
1301       D->hasWrittenPrototype())
1302     AbbrevToUse = Writer.getDeclCXXMethodAbbrev();
1303 
1304   Code = serialization::DECL_CXX_METHOD;
1305 }
1306 
1307 void ASTDeclWriter::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1308   if (auto Inherited = D->getInheritedConstructor()) {
1309     Record.AddDeclRef(Inherited.getShadowDecl());
1310     Record.AddDeclRef(Inherited.getConstructor());
1311     Code = serialization::DECL_CXX_INHERITED_CONSTRUCTOR;
1312   } else {
1313     Code = serialization::DECL_CXX_CONSTRUCTOR;
1314   }
1315 
1316   VisitCXXMethodDecl(D);
1317 
1318   Code = D->isInheritingConstructor()
1319              ? serialization::DECL_CXX_INHERITED_CONSTRUCTOR
1320              : serialization::DECL_CXX_CONSTRUCTOR;
1321 }
1322 
1323 void ASTDeclWriter::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1324   VisitCXXMethodDecl(D);
1325 
1326   Record.AddDeclRef(D->getOperatorDelete());
1327   if (D->getOperatorDelete())
1328     Record.AddStmt(D->getOperatorDeleteThisArg());
1329 
1330   Code = serialization::DECL_CXX_DESTRUCTOR;
1331 }
1332 
1333 void ASTDeclWriter::VisitCXXConversionDecl(CXXConversionDecl *D) {
1334   VisitCXXMethodDecl(D);
1335   Code = serialization::DECL_CXX_CONVERSION;
1336 }
1337 
1338 void ASTDeclWriter::VisitImportDecl(ImportDecl *D) {
1339   VisitDecl(D);
1340   Record.push_back(Writer.getSubmoduleID(D->getImportedModule()));
1341   ArrayRef<SourceLocation> IdentifierLocs = D->getIdentifierLocs();
1342   Record.push_back(!IdentifierLocs.empty());
1343   if (IdentifierLocs.empty()) {
1344     Record.AddSourceLocation(D->getLocEnd());
1345     Record.push_back(1);
1346   } else {
1347     for (unsigned I = 0, N = IdentifierLocs.size(); I != N; ++I)
1348       Record.AddSourceLocation(IdentifierLocs[I]);
1349     Record.push_back(IdentifierLocs.size());
1350   }
1351   // Note: the number of source locations must always be the last element in
1352   // the record.
1353   Code = serialization::DECL_IMPORT;
1354 }
1355 
1356 void ASTDeclWriter::VisitAccessSpecDecl(AccessSpecDecl *D) {
1357   VisitDecl(D);
1358   Record.AddSourceLocation(D->getColonLoc());
1359   Code = serialization::DECL_ACCESS_SPEC;
1360 }
1361 
1362 void ASTDeclWriter::VisitFriendDecl(FriendDecl *D) {
1363   // Record the number of friend type template parameter lists here
1364   // so as to simplify memory allocation during deserialization.
1365   Record.push_back(D->NumTPLists);
1366   VisitDecl(D);
1367   bool hasFriendDecl = D->Friend.is<NamedDecl*>();
1368   Record.push_back(hasFriendDecl);
1369   if (hasFriendDecl)
1370     Record.AddDeclRef(D->getFriendDecl());
1371   else
1372     Record.AddTypeSourceInfo(D->getFriendType());
1373   for (unsigned i = 0; i < D->NumTPLists; ++i)
1374     Record.AddTemplateParameterList(D->getFriendTypeTemplateParameterList(i));
1375   Record.AddDeclRef(D->getNextFriend());
1376   Record.push_back(D->UnsupportedFriend);
1377   Record.AddSourceLocation(D->FriendLoc);
1378   Code = serialization::DECL_FRIEND;
1379 }
1380 
1381 void ASTDeclWriter::VisitFriendTemplateDecl(FriendTemplateDecl *D) {
1382   VisitDecl(D);
1383   Record.push_back(D->getNumTemplateParameters());
1384   for (unsigned i = 0, e = D->getNumTemplateParameters(); i != e; ++i)
1385     Record.AddTemplateParameterList(D->getTemplateParameterList(i));
1386   Record.push_back(D->getFriendDecl() != nullptr);
1387   if (D->getFriendDecl())
1388     Record.AddDeclRef(D->getFriendDecl());
1389   else
1390     Record.AddTypeSourceInfo(D->getFriendType());
1391   Record.AddSourceLocation(D->getFriendLoc());
1392   Code = serialization::DECL_FRIEND_TEMPLATE;
1393 }
1394 
1395 void ASTDeclWriter::VisitTemplateDecl(TemplateDecl *D) {
1396   VisitNamedDecl(D);
1397 
1398   Record.AddDeclRef(D->getTemplatedDecl());
1399   Record.AddTemplateParameterList(D->getTemplateParameters());
1400 }
1401 
1402 void ASTDeclWriter::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
1403   VisitRedeclarable(D);
1404 
1405   // Emit data to initialize CommonOrPrev before VisitTemplateDecl so that
1406   // getCommonPtr() can be used while this is still initializing.
1407   if (D->isFirstDecl()) {
1408     // This declaration owns the 'common' pointer, so serialize that data now.
1409     Record.AddDeclRef(D->getInstantiatedFromMemberTemplate());
1410     if (D->getInstantiatedFromMemberTemplate())
1411       Record.push_back(D->isMemberSpecialization());
1412   }
1413 
1414   VisitTemplateDecl(D);
1415   Record.push_back(D->getIdentifierNamespace());
1416 }
1417 
1418 void ASTDeclWriter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
1419   VisitRedeclarableTemplateDecl(D);
1420 
1421   if (D->isFirstDecl())
1422     AddTemplateSpecializations(D);
1423   Code = serialization::DECL_CLASS_TEMPLATE;
1424 }
1425 
1426 void ASTDeclWriter::VisitClassTemplateSpecializationDecl(
1427                                            ClassTemplateSpecializationDecl *D) {
1428   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1429 
1430   VisitCXXRecordDecl(D);
1431 
1432   llvm::PointerUnion<ClassTemplateDecl *,
1433                      ClassTemplatePartialSpecializationDecl *> InstFrom
1434     = D->getSpecializedTemplateOrPartial();
1435   if (Decl *InstFromD = InstFrom.dyn_cast<ClassTemplateDecl *>()) {
1436     Record.AddDeclRef(InstFromD);
1437   } else {
1438     Record.AddDeclRef(InstFrom.get<ClassTemplatePartialSpecializationDecl *>());
1439     Record.AddTemplateArgumentList(&D->getTemplateInstantiationArgs());
1440   }
1441 
1442   Record.AddTemplateArgumentList(&D->getTemplateArgs());
1443   Record.AddSourceLocation(D->getPointOfInstantiation());
1444   Record.push_back(D->getSpecializationKind());
1445   Record.push_back(D->isCanonicalDecl());
1446 
1447   if (D->isCanonicalDecl()) {
1448     // When reading, we'll add it to the folding set of the following template.
1449     Record.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl());
1450   }
1451 
1452   // Explicit info.
1453   Record.AddTypeSourceInfo(D->getTypeAsWritten());
1454   if (D->getTypeAsWritten()) {
1455     Record.AddSourceLocation(D->getExternLoc());
1456     Record.AddSourceLocation(D->getTemplateKeywordLoc());
1457   }
1458 
1459   Code = serialization::DECL_CLASS_TEMPLATE_SPECIALIZATION;
1460 }
1461 
1462 void ASTDeclWriter::VisitClassTemplatePartialSpecializationDecl(
1463                                     ClassTemplatePartialSpecializationDecl *D) {
1464   VisitClassTemplateSpecializationDecl(D);
1465 
1466   Record.AddTemplateParameterList(D->getTemplateParameters());
1467   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1468 
1469   // These are read/set from/to the first declaration.
1470   if (D->getPreviousDecl() == nullptr) {
1471     Record.AddDeclRef(D->getInstantiatedFromMember());
1472     Record.push_back(D->isMemberSpecialization());
1473   }
1474 
1475   Code = serialization::DECL_CLASS_TEMPLATE_PARTIAL_SPECIALIZATION;
1476 }
1477 
1478 void ASTDeclWriter::VisitVarTemplateDecl(VarTemplateDecl *D) {
1479   VisitRedeclarableTemplateDecl(D);
1480 
1481   if (D->isFirstDecl())
1482     AddTemplateSpecializations(D);
1483   Code = serialization::DECL_VAR_TEMPLATE;
1484 }
1485 
1486 void ASTDeclWriter::VisitVarTemplateSpecializationDecl(
1487     VarTemplateSpecializationDecl *D) {
1488   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1489 
1490   VisitVarDecl(D);
1491 
1492   llvm::PointerUnion<VarTemplateDecl *, VarTemplatePartialSpecializationDecl *>
1493   InstFrom = D->getSpecializedTemplateOrPartial();
1494   if (Decl *InstFromD = InstFrom.dyn_cast<VarTemplateDecl *>()) {
1495     Record.AddDeclRef(InstFromD);
1496   } else {
1497     Record.AddDeclRef(InstFrom.get<VarTemplatePartialSpecializationDecl *>());
1498     Record.AddTemplateArgumentList(&D->getTemplateInstantiationArgs());
1499   }
1500 
1501   // Explicit info.
1502   Record.AddTypeSourceInfo(D->getTypeAsWritten());
1503   if (D->getTypeAsWritten()) {
1504     Record.AddSourceLocation(D->getExternLoc());
1505     Record.AddSourceLocation(D->getTemplateKeywordLoc());
1506   }
1507 
1508   Record.AddTemplateArgumentList(&D->getTemplateArgs());
1509   Record.AddSourceLocation(D->getPointOfInstantiation());
1510   Record.push_back(D->getSpecializationKind());
1511   Record.push_back(D->IsCompleteDefinition);
1512   Record.push_back(D->isCanonicalDecl());
1513 
1514   if (D->isCanonicalDecl()) {
1515     // When reading, we'll add it to the folding set of the following template.
1516     Record.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl());
1517   }
1518 
1519   Code = serialization::DECL_VAR_TEMPLATE_SPECIALIZATION;
1520 }
1521 
1522 void ASTDeclWriter::VisitVarTemplatePartialSpecializationDecl(
1523     VarTemplatePartialSpecializationDecl *D) {
1524   VisitVarTemplateSpecializationDecl(D);
1525 
1526   Record.AddTemplateParameterList(D->getTemplateParameters());
1527   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1528 
1529   // These are read/set from/to the first declaration.
1530   if (D->getPreviousDecl() == nullptr) {
1531     Record.AddDeclRef(D->getInstantiatedFromMember());
1532     Record.push_back(D->isMemberSpecialization());
1533   }
1534 
1535   Code = serialization::DECL_VAR_TEMPLATE_PARTIAL_SPECIALIZATION;
1536 }
1537 
1538 void ASTDeclWriter::VisitClassScopeFunctionSpecializationDecl(
1539                                     ClassScopeFunctionSpecializationDecl *D) {
1540   VisitDecl(D);
1541   Record.AddDeclRef(D->getSpecialization());
1542   Code = serialization::DECL_CLASS_SCOPE_FUNCTION_SPECIALIZATION;
1543 }
1544 
1545 
1546 void ASTDeclWriter::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
1547   VisitRedeclarableTemplateDecl(D);
1548 
1549   if (D->isFirstDecl())
1550     AddTemplateSpecializations(D);
1551   Code = serialization::DECL_FUNCTION_TEMPLATE;
1552 }
1553 
1554 void ASTDeclWriter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
1555   VisitTypeDecl(D);
1556 
1557   Record.push_back(D->wasDeclaredWithTypename());
1558 
1559   bool OwnsDefaultArg = D->hasDefaultArgument() &&
1560                         !D->defaultArgumentWasInherited();
1561   Record.push_back(OwnsDefaultArg);
1562   if (OwnsDefaultArg)
1563     Record.AddTypeSourceInfo(D->getDefaultArgumentInfo());
1564 
1565   Code = serialization::DECL_TEMPLATE_TYPE_PARM;
1566 }
1567 
1568 void ASTDeclWriter::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
1569   // For an expanded parameter pack, record the number of expansion types here
1570   // so that it's easier for deserialization to allocate the right amount of
1571   // memory.
1572   if (D->isExpandedParameterPack())
1573     Record.push_back(D->getNumExpansionTypes());
1574 
1575   VisitDeclaratorDecl(D);
1576   // TemplateParmPosition.
1577   Record.push_back(D->getDepth());
1578   Record.push_back(D->getPosition());
1579 
1580   if (D->isExpandedParameterPack()) {
1581     for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1582       Record.AddTypeRef(D->getExpansionType(I));
1583       Record.AddTypeSourceInfo(D->getExpansionTypeSourceInfo(I));
1584     }
1585 
1586     Code = serialization::DECL_EXPANDED_NON_TYPE_TEMPLATE_PARM_PACK;
1587   } else {
1588     // Rest of NonTypeTemplateParmDecl.
1589     Record.push_back(D->isParameterPack());
1590     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1591                           !D->defaultArgumentWasInherited();
1592     Record.push_back(OwnsDefaultArg);
1593     if (OwnsDefaultArg)
1594       Record.AddStmt(D->getDefaultArgument());
1595     Code = serialization::DECL_NON_TYPE_TEMPLATE_PARM;
1596   }
1597 }
1598 
1599 void ASTDeclWriter::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
1600   // For an expanded parameter pack, record the number of expansion types here
1601   // so that it's easier for deserialization to allocate the right amount of
1602   // memory.
1603   if (D->isExpandedParameterPack())
1604     Record.push_back(D->getNumExpansionTemplateParameters());
1605 
1606   VisitTemplateDecl(D);
1607   // TemplateParmPosition.
1608   Record.push_back(D->getDepth());
1609   Record.push_back(D->getPosition());
1610 
1611   if (D->isExpandedParameterPack()) {
1612     for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
1613          I != N; ++I)
1614       Record.AddTemplateParameterList(D->getExpansionTemplateParameters(I));
1615     Code = serialization::DECL_EXPANDED_TEMPLATE_TEMPLATE_PARM_PACK;
1616   } else {
1617     // Rest of TemplateTemplateParmDecl.
1618     Record.push_back(D->isParameterPack());
1619     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1620                           !D->defaultArgumentWasInherited();
1621     Record.push_back(OwnsDefaultArg);
1622     if (OwnsDefaultArg)
1623       Record.AddTemplateArgumentLoc(D->getDefaultArgument());
1624     Code = serialization::DECL_TEMPLATE_TEMPLATE_PARM;
1625   }
1626 }
1627 
1628 void ASTDeclWriter::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
1629   VisitRedeclarableTemplateDecl(D);
1630   Code = serialization::DECL_TYPE_ALIAS_TEMPLATE;
1631 }
1632 
1633 void ASTDeclWriter::VisitStaticAssertDecl(StaticAssertDecl *D) {
1634   VisitDecl(D);
1635   Record.AddStmt(D->getAssertExpr());
1636   Record.push_back(D->isFailed());
1637   Record.AddStmt(D->getMessage());
1638   Record.AddSourceLocation(D->getRParenLoc());
1639   Code = serialization::DECL_STATIC_ASSERT;
1640 }
1641 
1642 /// Emit the DeclContext part of a declaration context decl.
1643 void ASTDeclWriter::VisitDeclContext(DeclContext *DC) {
1644   Record.AddOffset(Writer.WriteDeclContextLexicalBlock(Context, DC));
1645   Record.AddOffset(Writer.WriteDeclContextVisibleBlock(Context, DC));
1646 }
1647 
1648 const Decl *ASTWriter::getFirstLocalDecl(const Decl *D) {
1649   assert(IsLocalDecl(D) && "expected a local declaration");
1650 
1651   const Decl *Canon = D->getCanonicalDecl();
1652   if (IsLocalDecl(Canon))
1653     return Canon;
1654 
1655   const Decl *&CacheEntry = FirstLocalDeclCache[Canon];
1656   if (CacheEntry)
1657     return CacheEntry;
1658 
1659   for (const Decl *Redecl = D; Redecl; Redecl = Redecl->getPreviousDecl())
1660     if (IsLocalDecl(Redecl))
1661       D = Redecl;
1662   return CacheEntry = D;
1663 }
1664 
1665 template <typename T>
1666 void ASTDeclWriter::VisitRedeclarable(Redeclarable<T> *D) {
1667   T *First = D->getFirstDecl();
1668   T *MostRecent = First->getMostRecentDecl();
1669   T *DAsT = static_cast<T *>(D);
1670   if (MostRecent != First) {
1671     assert(isRedeclarableDeclKind(DAsT->getKind()) &&
1672            "Not considered redeclarable?");
1673 
1674     Record.AddDeclRef(First);
1675 
1676     // Write out a list of local redeclarations of this declaration if it's the
1677     // first local declaration in the chain.
1678     const Decl *FirstLocal = Writer.getFirstLocalDecl(DAsT);
1679     if (DAsT == FirstLocal) {
1680       // Emit a list of all imported first declarations so that we can be sure
1681       // that all redeclarations visible to this module are before D in the
1682       // redecl chain.
1683       unsigned I = Record.size();
1684       Record.push_back(0);
1685       if (Writer.Chain)
1686         AddFirstDeclFromEachModule(DAsT, /*IncludeLocal*/false);
1687       // This is the number of imported first declarations + 1.
1688       Record[I] = Record.size() - I;
1689 
1690       // Collect the set of local redeclarations of this declaration, from
1691       // newest to oldest.
1692       ASTWriter::RecordData LocalRedecls;
1693       ASTRecordWriter LocalRedeclWriter(Record, LocalRedecls);
1694       for (const Decl *Prev = FirstLocal->getMostRecentDecl();
1695            Prev != FirstLocal; Prev = Prev->getPreviousDecl())
1696         if (!Prev->isFromASTFile())
1697           LocalRedeclWriter.AddDeclRef(Prev);
1698 
1699       // If we have any redecls, write them now as a separate record preceding
1700       // the declaration itself.
1701       if (LocalRedecls.empty())
1702         Record.push_back(0);
1703       else
1704         Record.AddOffset(LocalRedeclWriter.Emit(LOCAL_REDECLARATIONS));
1705     } else {
1706       Record.push_back(0);
1707       Record.AddDeclRef(FirstLocal);
1708     }
1709 
1710     // Make sure that we serialize both the previous and the most-recent
1711     // declarations, which (transitively) ensures that all declarations in the
1712     // chain get serialized.
1713     //
1714     // FIXME: This is not correct; when we reach an imported declaration we
1715     // won't emit its previous declaration.
1716     (void)Writer.GetDeclRef(D->getPreviousDecl());
1717     (void)Writer.GetDeclRef(MostRecent);
1718   } else {
1719     // We use the sentinel value 0 to indicate an only declaration.
1720     Record.push_back(0);
1721   }
1722 }
1723 
1724 void ASTDeclWriter::VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D) {
1725   Record.push_back(D->varlist_size());
1726   VisitDecl(D);
1727   for (auto *I : D->varlists())
1728     Record.AddStmt(I);
1729   Code = serialization::DECL_OMP_THREADPRIVATE;
1730 }
1731 
1732 void ASTDeclWriter::VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D) {
1733   VisitValueDecl(D);
1734   Record.AddSourceLocation(D->getLocStart());
1735   Record.AddStmt(D->getCombiner());
1736   Record.AddStmt(D->getInitializer());
1737   Record.push_back(D->getInitializerKind());
1738   Record.AddDeclRef(D->getPrevDeclInScope());
1739   Code = serialization::DECL_OMP_DECLARE_REDUCTION;
1740 }
1741 
1742 void ASTDeclWriter::VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D) {
1743   VisitVarDecl(D);
1744   Code = serialization::DECL_OMP_CAPTUREDEXPR;
1745 }
1746 
1747 //===----------------------------------------------------------------------===//
1748 // ASTWriter Implementation
1749 //===----------------------------------------------------------------------===//
1750 
1751 void ASTWriter::WriteDeclAbbrevs() {
1752   using namespace llvm;
1753 
1754   std::shared_ptr<BitCodeAbbrev> Abv;
1755 
1756   // Abbreviation for DECL_FIELD
1757   Abv = std::make_shared<BitCodeAbbrev>();
1758   Abv->Add(BitCodeAbbrevOp(serialization::DECL_FIELD));
1759   // Decl
1760   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1761   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1762   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1763   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1764   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1765   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1766   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1767   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1768   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1769   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1770   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1771   // NamedDecl
1772   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1773   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1774   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1775   // ValueDecl
1776   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1777   // DeclaratorDecl
1778   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1779   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1780   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
1781   // FieldDecl
1782   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1783   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
1784   // Type Source Info
1785   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1786   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1787   DeclFieldAbbrev = Stream.EmitAbbrev(std::move(Abv));
1788 
1789   // Abbreviation for DECL_OBJC_IVAR
1790   Abv = std::make_shared<BitCodeAbbrev>();
1791   Abv->Add(BitCodeAbbrevOp(serialization::DECL_OBJC_IVAR));
1792   // Decl
1793   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1794   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1795   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1796   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1797   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1798   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1799   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1800   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1801   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1802   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1803   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1804   // NamedDecl
1805   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1806   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1807   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1808   // ValueDecl
1809   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1810   // DeclaratorDecl
1811   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1812   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1813   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
1814   // FieldDecl
1815   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1816   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
1817   // ObjC Ivar
1818   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getAccessControl
1819   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getSynthesize
1820   // Type Source Info
1821   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1822   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1823   DeclObjCIvarAbbrev = Stream.EmitAbbrev(std::move(Abv));
1824 
1825   // Abbreviation for DECL_ENUM
1826   Abv = std::make_shared<BitCodeAbbrev>();
1827   Abv->Add(BitCodeAbbrevOp(serialization::DECL_ENUM));
1828   // Redeclarable
1829   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1830   // Decl
1831   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1832   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1833   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1834   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1835   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1836   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1837   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1838   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1839   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1840   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1841   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1842   // NamedDecl
1843   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1844   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1845   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1846   // TypeDecl
1847   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1848   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1849   // TagDecl
1850   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
1851   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
1852   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
1853   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
1854   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
1855   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
1856   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1857   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1858   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
1859   // EnumDecl
1860   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddTypeRef
1861   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IntegerType
1862   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getPromotionType
1863   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumPositiveBits
1864   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumNegativeBits
1865   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScoped
1866   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScopedUsingClassTag
1867   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isFixed
1868   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InstantiatedMembEnum
1869   // DC
1870   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
1871   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
1872   DeclEnumAbbrev = Stream.EmitAbbrev(std::move(Abv));
1873 
1874   // Abbreviation for DECL_RECORD
1875   Abv = std::make_shared<BitCodeAbbrev>();
1876   Abv->Add(BitCodeAbbrevOp(serialization::DECL_RECORD));
1877   // Redeclarable
1878   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1879   // Decl
1880   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1881   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1882   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1883   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1884   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1885   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1886   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1887   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1888   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1889   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1890   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1891   // NamedDecl
1892   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1893   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1894   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1895   // TypeDecl
1896   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1897   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1898   // TagDecl
1899   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
1900   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
1901   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
1902   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
1903   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
1904   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
1905   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1906   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1907   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
1908   // RecordDecl
1909   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // FlexibleArrayMember
1910   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // AnonymousStructUnion
1911   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasObjectMember
1912   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasVolatileMember
1913 
1914   // isNonTrivialToPrimitiveDefaultInitialize
1915   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1916   // isNonTrivialToPrimitiveCopy
1917   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1918   // isNonTrivialToPrimitiveDestroy
1919   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1920   // isParamDestroyedInCallee
1921   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1922   // getArgPassingRestrictions
1923   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));
1924 
1925   // DC
1926   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
1927   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
1928   DeclRecordAbbrev = Stream.EmitAbbrev(std::move(Abv));
1929 
1930   // Abbreviation for DECL_PARM_VAR
1931   Abv = std::make_shared<BitCodeAbbrev>();
1932   Abv->Add(BitCodeAbbrevOp(serialization::DECL_PARM_VAR));
1933   // Redeclarable
1934   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1935   // Decl
1936   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1937   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1938   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1939   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1940   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1941   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1942   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1943   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1944   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1945   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1946   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1947   // NamedDecl
1948   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1949   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1950   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1951   // ValueDecl
1952   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1953   // DeclaratorDecl
1954   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1955   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1956   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
1957   // VarDecl
1958   Abv->Add(BitCodeAbbrevOp(0));                       // SClass
1959   Abv->Add(BitCodeAbbrevOp(0));                       // TSCSpec
1960   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
1961   Abv->Add(BitCodeAbbrevOp(0));                       // Linkage
1962   Abv->Add(BitCodeAbbrevOp(0));                       // HasInit
1963   Abv->Add(BitCodeAbbrevOp(0));                   // HasMemberSpecializationInfo
1964   // ParmVarDecl
1965   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsObjCMethodParameter
1966   Abv->Add(BitCodeAbbrevOp(0));                       // ScopeDepth
1967   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ScopeIndex
1968   Abv->Add(BitCodeAbbrevOp(0));                       // ObjCDeclQualifier
1969   Abv->Add(BitCodeAbbrevOp(0));                       // KNRPromoted
1970   Abv->Add(BitCodeAbbrevOp(0));                       // HasInheritedDefaultArg
1971   Abv->Add(BitCodeAbbrevOp(0));                   // HasUninstantiatedDefaultArg
1972   // Type Source Info
1973   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1974   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1975   DeclParmVarAbbrev = Stream.EmitAbbrev(std::move(Abv));
1976 
1977   // Abbreviation for DECL_TYPEDEF
1978   Abv = std::make_shared<BitCodeAbbrev>();
1979   Abv->Add(BitCodeAbbrevOp(serialization::DECL_TYPEDEF));
1980   // Redeclarable
1981   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1982   // Decl
1983   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1984   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1985   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1986   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1987   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1988   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isUsed
1989   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isReferenced
1990   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1991   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // C++ AccessSpecifier
1992   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1993   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1994   // NamedDecl
1995   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1996   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1997   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1998   // TypeDecl
1999   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
2000   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
2001   // TypedefDecl
2002   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2003   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2004   DeclTypedefAbbrev = Stream.EmitAbbrev(std::move(Abv));
2005 
2006   // Abbreviation for DECL_VAR
2007   Abv = std::make_shared<BitCodeAbbrev>();
2008   Abv->Add(BitCodeAbbrevOp(serialization::DECL_VAR));
2009   // Redeclarable
2010   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2011   // Decl
2012   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2013   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2014   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2015   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2016   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2017   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2018   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2019   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2020   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2021   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2022   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2023   // NamedDecl
2024   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2025   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2026   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2027   // ValueDecl
2028   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2029   // DeclaratorDecl
2030   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
2031   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
2032   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
2033   // VarDecl
2034   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // SClass
2035   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // TSCSpec
2036   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // InitStyle
2037   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsThisDeclarationADemotedDefinition
2038   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isExceptionVariable
2039   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isNRVOVariable
2040   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCXXForRangeDecl
2041   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isObjCForDecl
2042   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isARCPseudoStrong
2043   Abv->Add(BitCodeAbbrevOp(0));                         // isInline
2044   Abv->Add(BitCodeAbbrevOp(0));                         // isInlineSpecified
2045   Abv->Add(BitCodeAbbrevOp(0));                         // isConstexpr
2046   Abv->Add(BitCodeAbbrevOp(0));                         // isInitCapture
2047   Abv->Add(BitCodeAbbrevOp(0));                         // isPrevDeclInSameScope
2048   Abv->Add(BitCodeAbbrevOp(0));                         // ImplicitParamKind
2049   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
2050   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // IsInitICE (local)
2051   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // VarKind (local enum)
2052   // Type Source Info
2053   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2054   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2055   DeclVarAbbrev = Stream.EmitAbbrev(std::move(Abv));
2056 
2057   // Abbreviation for DECL_CXX_METHOD
2058   Abv = std::make_shared<BitCodeAbbrev>();
2059   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CXX_METHOD));
2060   // RedeclarableDecl
2061   Abv->Add(BitCodeAbbrevOp(0));                         // CanonicalDecl
2062   // Decl
2063   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // DeclContext
2064   Abv->Add(BitCodeAbbrevOp(0));                         // LexicalDeclContext
2065   Abv->Add(BitCodeAbbrevOp(0));                         // Invalid
2066   Abv->Add(BitCodeAbbrevOp(0));                         // HasAttrs
2067   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Implicit
2068   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Used
2069   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Referenced
2070   Abv->Add(BitCodeAbbrevOp(0));                         // InObjCContainer
2071   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // Access
2072   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ModulePrivate
2073   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SubmoduleID
2074   // NamedDecl
2075   Abv->Add(BitCodeAbbrevOp(DeclarationName::Identifier)); // NameKind
2076   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Identifier
2077   Abv->Add(BitCodeAbbrevOp(0));                         // AnonDeclNumber
2078   // ValueDecl
2079   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Type
2080   // DeclaratorDecl
2081   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InnerLocStart
2082   Abv->Add(BitCodeAbbrevOp(0));                         // HasExtInfo
2083   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // TSIType
2084   // FunctionDecl
2085   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 11)); // IDNS
2086   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // StorageClass
2087   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Inline
2088   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // InlineSpecified
2089   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ExplicitSpecified
2090   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // VirtualAsWritten
2091   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Pure
2092   Abv->Add(BitCodeAbbrevOp(0));                         // HasInheritedProto
2093   Abv->Add(BitCodeAbbrevOp(1));                         // HasWrittenProto
2094   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Deleted
2095   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Trivial
2096   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // TrivialForCall
2097   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Defaulted
2098   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ExplicitlyDefaulted
2099   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ImplicitReturnZero
2100   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Constexpr
2101   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // UsesSEHTry
2102   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // SkippedBody
2103   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // MultiVersion
2104   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // LateParsed
2105   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
2106   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LocEnd
2107   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32)); // ODRHash
2108   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // TemplateKind
2109   // This Array slurps the rest of the record. Fortunately we want to encode
2110   // (nearly) all the remaining (variable number of) fields in the same way.
2111   //
2112   // This is the function template information if any, then
2113   //         NumParams and Params[] from FunctionDecl, and
2114   //         NumOverriddenMethods, OverriddenMethods[] from CXXMethodDecl.
2115   //
2116   //  Add an AbbrevOp for 'size then elements' and use it here.
2117   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2118   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2119   DeclCXXMethodAbbrev = Stream.EmitAbbrev(std::move(Abv));
2120 
2121   // Abbreviation for EXPR_DECL_REF
2122   Abv = std::make_shared<BitCodeAbbrev>();
2123   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_DECL_REF));
2124   //Stmt
2125   //Expr
2126   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2127   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2128   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2129   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2130   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2131   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2132   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2133   //DeclRefExpr
2134   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HasQualifier
2135   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //GetDeclFound
2136   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ExplicitTemplateArgs
2137   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HadMultipleCandidates
2138   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2139                            1)); // RefersToEnclosingVariableOrCapture
2140   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclRef
2141   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2142   DeclRefExprAbbrev = Stream.EmitAbbrev(std::move(Abv));
2143 
2144   // Abbreviation for EXPR_INTEGER_LITERAL
2145   Abv = std::make_shared<BitCodeAbbrev>();
2146   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_INTEGER_LITERAL));
2147   //Stmt
2148   //Expr
2149   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2150   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2151   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2152   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2153   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2154   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2155   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2156   //Integer Literal
2157   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2158   Abv->Add(BitCodeAbbrevOp(32));                      // Bit Width
2159   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Value
2160   IntegerLiteralAbbrev = Stream.EmitAbbrev(std::move(Abv));
2161 
2162   // Abbreviation for EXPR_CHARACTER_LITERAL
2163   Abv = std::make_shared<BitCodeAbbrev>();
2164   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_CHARACTER_LITERAL));
2165   //Stmt
2166   //Expr
2167   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2168   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2169   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2170   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2171   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2172   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2173   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2174   //Character Literal
2175   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getValue
2176   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2177   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // getKind
2178   CharacterLiteralAbbrev = Stream.EmitAbbrev(std::move(Abv));
2179 
2180   // Abbreviation for EXPR_IMPLICIT_CAST
2181   Abv = std::make_shared<BitCodeAbbrev>();
2182   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_IMPLICIT_CAST));
2183   // Stmt
2184   // Expr
2185   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2186   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2187   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2188   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2189   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2190   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2191   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2192   // CastExpr
2193   Abv->Add(BitCodeAbbrevOp(0)); // PathSize
2194   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 6)); // CastKind
2195   // ImplicitCastExpr
2196   ExprImplicitCastAbbrev = Stream.EmitAbbrev(std::move(Abv));
2197 
2198   Abv = std::make_shared<BitCodeAbbrev>();
2199   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_LEXICAL));
2200   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2201   DeclContextLexicalAbbrev = Stream.EmitAbbrev(std::move(Abv));
2202 
2203   Abv = std::make_shared<BitCodeAbbrev>();
2204   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_VISIBLE));
2205   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2206   DeclContextVisibleLookupAbbrev = Stream.EmitAbbrev(std::move(Abv));
2207 }
2208 
2209 /// isRequiredDecl - Check if this is a "required" Decl, which must be seen by
2210 /// consumers of the AST.
2211 ///
2212 /// Such decls will always be deserialized from the AST file, so we would like
2213 /// this to be as restrictive as possible. Currently the predicate is driven by
2214 /// code generation requirements, if other clients have a different notion of
2215 /// what is "required" then we may have to consider an alternate scheme where
2216 /// clients can iterate over the top-level decls and get information on them,
2217 /// without necessary deserializing them. We could explicitly require such
2218 /// clients to use a separate API call to "realize" the decl. This should be
2219 /// relatively painless since they would presumably only do it for top-level
2220 /// decls.
2221 static bool isRequiredDecl(const Decl *D, ASTContext &Context,
2222                            bool WritingModule) {
2223   // An ObjCMethodDecl is never considered as "required" because its
2224   // implementation container always is.
2225 
2226   // File scoped assembly or obj-c or OMP declare target implementation must be
2227   // seen.
2228   if (isa<FileScopeAsmDecl>(D) || isa<ObjCImplDecl>(D) ||
2229       D->hasAttr<OMPDeclareTargetDeclAttr>())
2230     return true;
2231 
2232   if (WritingModule && (isa<VarDecl>(D) || isa<ImportDecl>(D))) {
2233     // These declarations are part of the module initializer, and are emitted
2234     // if and when the module is imported, rather than being emitted eagerly.
2235     return false;
2236   }
2237 
2238   return Context.DeclMustBeEmitted(D);
2239 }
2240 
2241 void ASTWriter::WriteDecl(ASTContext &Context, Decl *D) {
2242   PrettyDeclStackTraceEntry CrashInfo(Context, D, SourceLocation(),
2243                                       "serializing");
2244 
2245   // Determine the ID for this declaration.
2246   serialization::DeclID ID;
2247   assert(!D->isFromASTFile() && "should not be emitting imported decl");
2248   serialization::DeclID &IDR = DeclIDs[D];
2249   if (IDR == 0)
2250     IDR = NextDeclID++;
2251 
2252   ID = IDR;
2253 
2254   assert(ID >= FirstDeclID && "invalid decl ID");
2255 
2256   RecordData Record;
2257   ASTDeclWriter W(*this, Context, Record);
2258 
2259   // Build a record for this declaration
2260   W.Visit(D);
2261 
2262   // Emit this declaration to the bitstream.
2263   uint64_t Offset = W.Emit(D);
2264 
2265   // Record the offset for this declaration
2266   SourceLocation Loc = D->getLocation();
2267   unsigned Index = ID - FirstDeclID;
2268   if (DeclOffsets.size() == Index)
2269     DeclOffsets.push_back(DeclOffset(Loc, Offset));
2270   else if (DeclOffsets.size() < Index) {
2271     // FIXME: Can/should this happen?
2272     DeclOffsets.resize(Index+1);
2273     DeclOffsets[Index].setLocation(Loc);
2274     DeclOffsets[Index].BitOffset = Offset;
2275   } else {
2276     llvm_unreachable("declarations should be emitted in ID order");
2277   }
2278 
2279   SourceManager &SM = Context.getSourceManager();
2280   if (Loc.isValid() && SM.isLocalSourceLocation(Loc))
2281     associateDeclWithFile(D, ID);
2282 
2283   // Note declarations that should be deserialized eagerly so that we can add
2284   // them to a record in the AST file later.
2285   if (isRequiredDecl(D, Context, WritingModule))
2286     EagerlyDeserializedDecls.push_back(ID);
2287 }
2288 
2289 void ASTRecordWriter::AddFunctionDefinition(const FunctionDecl *FD) {
2290   // Switch case IDs are per function body.
2291   Writer->ClearSwitchCaseIDs();
2292 
2293   assert(FD->doesThisDeclarationHaveABody());
2294   bool ModulesCodegen = false;
2295   if (Writer->WritingModule && !FD->isDependentContext()) {
2296     Optional<GVALinkage> Linkage;
2297     if (Writer->WritingModule->Kind == Module::ModuleInterfaceUnit) {
2298       // When building a C++ Modules TS module interface unit, a strong
2299       // definition in the module interface is provided by the compilation of
2300       // that module interface unit, not by its users. (Inline functions are
2301       // still emitted in module users.)
2302       Linkage = Writer->Context->GetGVALinkageForFunction(FD);
2303       ModulesCodegen = *Linkage == GVA_StrongExternal;
2304     }
2305     if (Writer->Context->getLangOpts().ModulesCodegen) {
2306       // Under -fmodules-codegen, codegen is performed for all non-internal,
2307       // non-always_inline functions.
2308       if (!FD->hasAttr<AlwaysInlineAttr>()) {
2309         if (!Linkage)
2310           Linkage = Writer->Context->GetGVALinkageForFunction(FD);
2311         ModulesCodegen = *Linkage != GVA_Internal;
2312       }
2313     }
2314   }
2315   Record->push_back(ModulesCodegen);
2316   if (ModulesCodegen)
2317     Writer->ModularCodegenDecls.push_back(Writer->GetDeclRef(FD));
2318   if (auto *CD = dyn_cast<CXXConstructorDecl>(FD)) {
2319     Record->push_back(CD->getNumCtorInitializers());
2320     if (CD->getNumCtorInitializers())
2321       AddCXXCtorInitializers(
2322           llvm::makeArrayRef(CD->init_begin(), CD->init_end()));
2323   }
2324   AddStmt(FD->getBody());
2325 }
2326