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