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