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