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