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