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