1 //===--- ASTWriterDecl.cpp - Declaration Serialization --------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //  This file implements serialization for Declarations.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "ASTCommon.h"
15 #include "clang/AST/DeclCXX.h"
16 #include "clang/AST/DeclContextInternals.h"
17 #include "clang/AST/DeclTemplate.h"
18 #include "clang/AST/DeclVisitor.h"
19 #include "clang/AST/Expr.h"
20 #include "clang/Basic/SourceManager.h"
21 #include "clang/Serialization/ASTReader.h"
22 #include "clang/Serialization/ASTWriter.h"
23 #include "llvm/Bitcode/BitstreamWriter.h"
24 #include "llvm/Support/ErrorHandling.h"
25 using namespace clang;
26 using namespace serialization;
27 
28 //===----------------------------------------------------------------------===//
29 // Declaration serialization
30 //===----------------------------------------------------------------------===//
31 
32 namespace clang {
33   class ASTDeclWriter : public DeclVisitor<ASTDeclWriter, void> {
34     ASTWriter &Writer;
35     ASTContext &Context;
36     ASTRecordWriter Record;
37 
38     serialization::DeclCode Code;
39     unsigned AbbrevToUse;
40 
41   public:
42     ASTDeclWriter(ASTWriter &Writer, ASTContext &Context,
43                   ASTWriter::RecordDataImpl &Record)
44         : Writer(Writer), Context(Context), Record(Writer, Record),
45           Code((serialization::DeclCode)0), AbbrevToUse(0) {}
46 
47     uint64_t Emit(Decl *D) {
48       if (!Code)
49         llvm::report_fatal_error(StringRef("unexpected declaration kind '") +
50             D->getDeclKindName() + "'");
51       return Record.Emit(Code, AbbrevToUse);
52     }
53 
54     void Visit(Decl *D);
55 
56     void VisitDecl(Decl *D);
57     void VisitPragmaCommentDecl(PragmaCommentDecl *D);
58     void VisitPragmaDetectMismatchDecl(PragmaDetectMismatchDecl *D);
59     void VisitTranslationUnitDecl(TranslationUnitDecl *D);
60     void VisitNamedDecl(NamedDecl *D);
61     void VisitLabelDecl(LabelDecl *LD);
62     void VisitNamespaceDecl(NamespaceDecl *D);
63     void VisitUsingDirectiveDecl(UsingDirectiveDecl *D);
64     void VisitNamespaceAliasDecl(NamespaceAliasDecl *D);
65     void VisitTypeDecl(TypeDecl *D);
66     void VisitTypedefNameDecl(TypedefNameDecl *D);
67     void VisitTypedefDecl(TypedefDecl *D);
68     void VisitTypeAliasDecl(TypeAliasDecl *D);
69     void VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D);
70     void VisitTagDecl(TagDecl *D);
71     void VisitEnumDecl(EnumDecl *D);
72     void VisitRecordDecl(RecordDecl *D);
73     void VisitCXXRecordDecl(CXXRecordDecl *D);
74     void VisitClassTemplateSpecializationDecl(
75                                             ClassTemplateSpecializationDecl *D);
76     void VisitClassTemplatePartialSpecializationDecl(
77                                      ClassTemplatePartialSpecializationDecl *D);
78     void VisitVarTemplateSpecializationDecl(VarTemplateSpecializationDecl *D);
79     void VisitVarTemplatePartialSpecializationDecl(
80         VarTemplatePartialSpecializationDecl *D);
81     void VisitClassScopeFunctionSpecializationDecl(
82                                        ClassScopeFunctionSpecializationDecl *D);
83     void VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
84     void VisitValueDecl(ValueDecl *D);
85     void VisitEnumConstantDecl(EnumConstantDecl *D);
86     void VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D);
87     void VisitDeclaratorDecl(DeclaratorDecl *D);
88     void VisitFunctionDecl(FunctionDecl *D);
89     void VisitCXXDeductionGuideDecl(CXXDeductionGuideDecl *D);
90     void VisitCXXMethodDecl(CXXMethodDecl *D);
91     void VisitCXXConstructorDecl(CXXConstructorDecl *D);
92     void VisitCXXDestructorDecl(CXXDestructorDecl *D);
93     void VisitCXXConversionDecl(CXXConversionDecl *D);
94     void VisitFieldDecl(FieldDecl *D);
95     void VisitMSPropertyDecl(MSPropertyDecl *D);
96     void VisitIndirectFieldDecl(IndirectFieldDecl *D);
97     void VisitVarDecl(VarDecl *D);
98     void VisitImplicitParamDecl(ImplicitParamDecl *D);
99     void VisitParmVarDecl(ParmVarDecl *D);
100     void VisitDecompositionDecl(DecompositionDecl *D);
101     void VisitBindingDecl(BindingDecl *D);
102     void VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
103     void VisitTemplateDecl(TemplateDecl *D);
104     void VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D);
105     void VisitClassTemplateDecl(ClassTemplateDecl *D);
106     void VisitVarTemplateDecl(VarTemplateDecl *D);
107     void VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
108     void VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
109     void VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D);
110     void VisitUsingDecl(UsingDecl *D);
111     void VisitUsingPackDecl(UsingPackDecl *D);
112     void VisitUsingShadowDecl(UsingShadowDecl *D);
113     void VisitConstructorUsingShadowDecl(ConstructorUsingShadowDecl *D);
114     void VisitLinkageSpecDecl(LinkageSpecDecl *D);
115     void VisitExportDecl(ExportDecl *D);
116     void VisitFileScopeAsmDecl(FileScopeAsmDecl *D);
117     void VisitImportDecl(ImportDecl *D);
118     void VisitAccessSpecDecl(AccessSpecDecl *D);
119     void VisitFriendDecl(FriendDecl *D);
120     void VisitFriendTemplateDecl(FriendTemplateDecl *D);
121     void VisitStaticAssertDecl(StaticAssertDecl *D);
122     void VisitBlockDecl(BlockDecl *D);
123     void VisitCapturedDecl(CapturedDecl *D);
124     void VisitEmptyDecl(EmptyDecl *D);
125 
126     void VisitDeclContext(DeclContext *DC);
127     template <typename T> void VisitRedeclarable(Redeclarable<T> *D);
128 
129 
130     // FIXME: Put in the same order is DeclNodes.td?
131     void VisitObjCMethodDecl(ObjCMethodDecl *D);
132     void VisitObjCTypeParamDecl(ObjCTypeParamDecl *D);
133     void VisitObjCContainerDecl(ObjCContainerDecl *D);
134     void VisitObjCInterfaceDecl(ObjCInterfaceDecl *D);
135     void VisitObjCIvarDecl(ObjCIvarDecl *D);
136     void VisitObjCProtocolDecl(ObjCProtocolDecl *D);
137     void VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D);
138     void VisitObjCCategoryDecl(ObjCCategoryDecl *D);
139     void VisitObjCImplDecl(ObjCImplDecl *D);
140     void VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D);
141     void VisitObjCImplementationDecl(ObjCImplementationDecl *D);
142     void VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D);
143     void VisitObjCPropertyDecl(ObjCPropertyDecl *D);
144     void VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D);
145     void VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D);
146     void VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D);
147     void VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D);
148 
149     /// Add an Objective-C type parameter list to the given record.
150     void AddObjCTypeParamList(ObjCTypeParamList *typeParams) {
151       // Empty type parameter list.
152       if (!typeParams) {
153         Record.push_back(0);
154         return;
155       }
156 
157       Record.push_back(typeParams->size());
158       for (auto typeParam : *typeParams) {
159         Record.AddDeclRef(typeParam);
160       }
161       Record.AddSourceLocation(typeParams->getLAngleLoc());
162       Record.AddSourceLocation(typeParams->getRAngleLoc());
163     }
164 
165     /// Add to the record the first declaration from each module file that
166     /// provides a declaration of D. The intent is to provide a sufficient
167     /// set such that reloading this set will load all current redeclarations.
168     void AddFirstDeclFromEachModule(const Decl *D, bool IncludeLocal) {
169       llvm::MapVector<ModuleFile*, const Decl*> Firsts;
170       // FIXME: We can skip entries that we know are implied by others.
171       for (const Decl *R = D->getMostRecentDecl(); R; R = R->getPreviousDecl()) {
172         if (R->isFromASTFile())
173           Firsts[Writer.Chain->getOwningModuleFile(R)] = R;
174         else if (IncludeLocal)
175           Firsts[nullptr] = R;
176       }
177       for (const auto &F : Firsts)
178         Record.AddDeclRef(F.second);
179     }
180 
181     /// Get the specialization decl from an entry in the specialization list.
182     template <typename EntryType>
183     typename RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::DeclType *
184     getSpecializationDecl(EntryType &T) {
185       return RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::getDecl(&T);
186     }
187 
188     /// Get the list of partial specializations from a template's common ptr.
189     template<typename T>
190     decltype(T::PartialSpecializations) &getPartialSpecializations(T *Common) {
191       return Common->PartialSpecializations;
192     }
193     ArrayRef<Decl> getPartialSpecializations(FunctionTemplateDecl::Common *) {
194       return None;
195     }
196 
197     template<typename DeclTy>
198     void AddTemplateSpecializations(DeclTy *D) {
199       auto *Common = D->getCommonPtr();
200 
201       // If we have any lazy specializations, and the external AST source is
202       // our chained AST reader, we can just write out the DeclIDs. Otherwise,
203       // we need to resolve them to actual declarations.
204       if (Writer.Chain != Writer.Context->getExternalSource() &&
205           Common->LazySpecializations) {
206         D->LoadLazySpecializations();
207         assert(!Common->LazySpecializations);
208       }
209 
210       ArrayRef<DeclID> LazySpecializations;
211       if (auto *LS = Common->LazySpecializations)
212         LazySpecializations = llvm::makeArrayRef(LS + 1, LS[0]);
213 
214       // Add a slot to the record for the number of specializations.
215       unsigned I = Record.size();
216       Record.push_back(0);
217 
218       // AddFirstDeclFromEachModule might trigger deserialization, invalidating
219       // *Specializations iterators.
220       llvm::SmallVector<const Decl*, 16> Specs;
221       for (auto &Entry : Common->Specializations)
222         Specs.push_back(getSpecializationDecl(Entry));
223       for (auto &Entry : getPartialSpecializations(Common))
224         Specs.push_back(getSpecializationDecl(Entry));
225 
226       for (auto *D : Specs) {
227         assert(D->isCanonicalDecl() && "non-canonical decl in set");
228         AddFirstDeclFromEachModule(D, /*IncludeLocal*/true);
229       }
230       Record.append(LazySpecializations.begin(), LazySpecializations.end());
231 
232       // Update the size entry we added earlier.
233       Record[I] = Record.size() - I - 1;
234     }
235 
236     /// Ensure that this template specialization is associated with the specified
237     /// template on reload.
238     void RegisterTemplateSpecialization(const Decl *Template,
239                                         const Decl *Specialization) {
240       Template = Template->getCanonicalDecl();
241 
242       // If the canonical template is local, we'll write out this specialization
243       // when we emit it.
244       // FIXME: We can do the same thing if there is any local declaration of
245       // the template, to avoid emitting an update record.
246       if (!Template->isFromASTFile())
247         return;
248 
249       // We only need to associate the first local declaration of the
250       // specialization. The other declarations will get pulled in by it.
251       if (Writer.getFirstLocalDecl(Specialization) != Specialization)
252         return;
253 
254       Writer.DeclUpdates[Template].push_back(ASTWriter::DeclUpdate(
255           UPD_CXX_ADDED_TEMPLATE_SPECIALIZATION, Specialization));
256     }
257   };
258 }
259 
260 void ASTDeclWriter::Visit(Decl *D) {
261   DeclVisitor<ASTDeclWriter>::Visit(D);
262 
263   // Source locations require array (variable-length) abbreviations.  The
264   // abbreviation infrastructure requires that arrays are encoded last, so
265   // we handle it here in the case of those classes derived from DeclaratorDecl
266   if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D)) {
267     Record.AddTypeSourceInfo(DD->getTypeSourceInfo());
268   }
269 
270   // Handle FunctionDecl's body here and write it after all other Stmts/Exprs
271   // have been written. We want it last because we will not read it back when
272   // retrieving it from the AST, we'll just lazily set the offset.
273   if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
274     Record.push_back(FD->doesThisDeclarationHaveABody());
275     if (FD->doesThisDeclarationHaveABody())
276       Record.AddFunctionDefinition(FD);
277   }
278 
279   // If this declaration is also a DeclContext, write blocks for the
280   // declarations that lexically stored inside its context and those
281   // declarations that are visible from its context.
282   if (DeclContext *DC = dyn_cast<DeclContext>(D))
283     VisitDeclContext(DC);
284 }
285 
286 void ASTDeclWriter::VisitDecl(Decl *D) {
287   Record.AddDeclRef(cast_or_null<Decl>(D->getDeclContext()));
288   if (D->getDeclContext() != D->getLexicalDeclContext())
289     Record.AddDeclRef(cast_or_null<Decl>(D->getLexicalDeclContext()));
290   else
291     Record.push_back(0);
292   Record.push_back(D->isInvalidDecl());
293   Record.push_back(D->hasAttrs());
294   if (D->hasAttrs())
295     Record.AddAttributes(D->getAttrs());
296   Record.push_back(D->isImplicit());
297   Record.push_back(D->isUsed(false));
298   Record.push_back(D->isReferenced());
299   Record.push_back(D->isTopLevelDeclInObjCContainer());
300   Record.push_back(D->getAccess());
301   Record.push_back(D->isModulePrivate());
302   Record.push_back(Writer.getSubmoduleID(D->getOwningModule()));
303 
304   // If this declaration injected a name into a context different from its
305   // lexical context, and that context is an imported namespace, we need to
306   // update its visible declarations to include this name.
307   //
308   // This happens when we instantiate a class with a friend declaration or a
309   // function with a local extern declaration, for instance.
310   //
311   // FIXME: Can we handle this in AddedVisibleDecl instead?
312   if (D->isOutOfLine()) {
313     auto *DC = D->getDeclContext();
314     while (auto *NS = dyn_cast<NamespaceDecl>(DC->getRedeclContext())) {
315       if (!NS->isFromASTFile())
316         break;
317       Writer.UpdatedDeclContexts.insert(NS->getPrimaryContext());
318       if (!NS->isInlineNamespace())
319         break;
320       DC = NS->getParent();
321     }
322   }
323 }
324 
325 void ASTDeclWriter::VisitPragmaCommentDecl(PragmaCommentDecl *D) {
326   StringRef Arg = D->getArg();
327   Record.push_back(Arg.size());
328   VisitDecl(D);
329   Record.AddSourceLocation(D->getLocStart());
330   Record.push_back(D->getCommentKind());
331   Record.AddString(Arg);
332   Code = serialization::DECL_PRAGMA_COMMENT;
333 }
334 
335 void ASTDeclWriter::VisitPragmaDetectMismatchDecl(
336     PragmaDetectMismatchDecl *D) {
337   StringRef Name = D->getName();
338   StringRef Value = D->getValue();
339   Record.push_back(Name.size() + 1 + Value.size());
340   VisitDecl(D);
341   Record.AddSourceLocation(D->getLocStart());
342   Record.AddString(Name);
343   Record.AddString(Value);
344   Code = serialization::DECL_PRAGMA_DETECT_MISMATCH;
345 }
346 
347 void ASTDeclWriter::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
348   llvm_unreachable("Translation units aren't directly serialized");
349 }
350 
351 void ASTDeclWriter::VisitNamedDecl(NamedDecl *D) {
352   VisitDecl(D);
353   Record.AddDeclarationName(D->getDeclName());
354   Record.push_back(needsAnonymousDeclarationNumber(D)
355                        ? Writer.getAnonymousDeclarationNumber(D)
356                        : 0);
357 }
358 
359 void ASTDeclWriter::VisitTypeDecl(TypeDecl *D) {
360   VisitNamedDecl(D);
361   Record.AddSourceLocation(D->getLocStart());
362   Record.AddTypeRef(QualType(D->getTypeForDecl(), 0));
363 }
364 
365 void ASTDeclWriter::VisitTypedefNameDecl(TypedefNameDecl *D) {
366   VisitRedeclarable(D);
367   VisitTypeDecl(D);
368   Record.AddTypeSourceInfo(D->getTypeSourceInfo());
369   Record.push_back(D->isModed());
370   if (D->isModed())
371     Record.AddTypeRef(D->getUnderlyingType());
372   Record.AddDeclRef(D->getAnonDeclWithTypedefName(false));
373 }
374 
375 void ASTDeclWriter::VisitTypedefDecl(TypedefDecl *D) {
376   VisitTypedefNameDecl(D);
377   if (D->getDeclContext() == D->getLexicalDeclContext() &&
378       !D->hasAttrs() &&
379       !D->isImplicit() &&
380       D->getFirstDecl() == D->getMostRecentDecl() &&
381       !D->isInvalidDecl() &&
382       !D->isTopLevelDeclInObjCContainer() &&
383       !D->isModulePrivate() &&
384       !needsAnonymousDeclarationNumber(D) &&
385       D->getDeclName().getNameKind() == DeclarationName::Identifier)
386     AbbrevToUse = Writer.getDeclTypedefAbbrev();
387 
388   Code = serialization::DECL_TYPEDEF;
389 }
390 
391 void ASTDeclWriter::VisitTypeAliasDecl(TypeAliasDecl *D) {
392   VisitTypedefNameDecl(D);
393   Record.AddDeclRef(D->getDescribedAliasTemplate());
394   Code = serialization::DECL_TYPEALIAS;
395 }
396 
397 void ASTDeclWriter::VisitTagDecl(TagDecl *D) {
398   VisitRedeclarable(D);
399   VisitTypeDecl(D);
400   Record.push_back(D->getIdentifierNamespace());
401   Record.push_back((unsigned)D->getTagKind()); // FIXME: stable encoding
402   if (!isa<CXXRecordDecl>(D))
403     Record.push_back(D->isCompleteDefinition());
404   Record.push_back(D->isEmbeddedInDeclarator());
405   Record.push_back(D->isFreeStanding());
406   Record.push_back(D->isCompleteDefinitionRequired());
407   Record.AddSourceRange(D->getBraceRange());
408 
409   if (D->hasExtInfo()) {
410     Record.push_back(1);
411     Record.AddQualifierInfo(*D->getExtInfo());
412   } else if (auto *TD = D->getTypedefNameForAnonDecl()) {
413     Record.push_back(2);
414     Record.AddDeclRef(TD);
415     Record.AddIdentifierRef(TD->getDeclName().getAsIdentifierInfo());
416   } else {
417     Record.push_back(0);
418   }
419 }
420 
421 void ASTDeclWriter::VisitEnumDecl(EnumDecl *D) {
422   VisitTagDecl(D);
423   Record.AddTypeSourceInfo(D->getIntegerTypeSourceInfo());
424   if (!D->getIntegerTypeSourceInfo())
425     Record.AddTypeRef(D->getIntegerType());
426   Record.AddTypeRef(D->getPromotionType());
427   Record.push_back(D->getNumPositiveBits());
428   Record.push_back(D->getNumNegativeBits());
429   Record.push_back(D->isScoped());
430   Record.push_back(D->isScopedUsingClassTag());
431   Record.push_back(D->isFixed());
432   if (MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo()) {
433     Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
434     Record.push_back(MemberInfo->getTemplateSpecializationKind());
435     Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
436   } else {
437     Record.AddDeclRef(nullptr);
438   }
439 
440   if (D->getDeclContext() == D->getLexicalDeclContext() &&
441       !D->hasAttrs() &&
442       !D->isImplicit() &&
443       !D->isUsed(false) &&
444       !D->hasExtInfo() &&
445       !D->getTypedefNameForAnonDecl() &&
446       D->getFirstDecl() == D->getMostRecentDecl() &&
447       !D->isInvalidDecl() &&
448       !D->isReferenced() &&
449       !D->isTopLevelDeclInObjCContainer() &&
450       D->getAccess() == AS_none &&
451       !D->isModulePrivate() &&
452       !CXXRecordDecl::classofKind(D->getKind()) &&
453       !D->getIntegerTypeSourceInfo() &&
454       !D->getMemberSpecializationInfo() &&
455       !needsAnonymousDeclarationNumber(D) &&
456       D->getDeclName().getNameKind() == DeclarationName::Identifier)
457     AbbrevToUse = Writer.getDeclEnumAbbrev();
458 
459   Code = serialization::DECL_ENUM;
460 }
461 
462 void ASTDeclWriter::VisitRecordDecl(RecordDecl *D) {
463   VisitTagDecl(D);
464   Record.push_back(D->hasFlexibleArrayMember());
465   Record.push_back(D->isAnonymousStructOrUnion());
466   Record.push_back(D->hasObjectMember());
467   Record.push_back(D->hasVolatileMember());
468   Record.push_back(D->isNonTrivialToPrimitiveDefaultInitialize());
469   Record.push_back(D->isNonTrivialToPrimitiveCopy());
470   Record.push_back(D->isNonTrivialToPrimitiveDestroy());
471 
472   if (D->getDeclContext() == D->getLexicalDeclContext() &&
473       !D->hasAttrs() &&
474       !D->isImplicit() &&
475       !D->isUsed(false) &&
476       !D->hasExtInfo() &&
477       !D->getTypedefNameForAnonDecl() &&
478       D->getFirstDecl() == D->getMostRecentDecl() &&
479       !D->isInvalidDecl() &&
480       !D->isReferenced() &&
481       !D->isTopLevelDeclInObjCContainer() &&
482       D->getAccess() == AS_none &&
483       !D->isModulePrivate() &&
484       !CXXRecordDecl::classofKind(D->getKind()) &&
485       !needsAnonymousDeclarationNumber(D) &&
486       D->getDeclName().getNameKind() == DeclarationName::Identifier)
487     AbbrevToUse = Writer.getDeclRecordAbbrev();
488 
489   Code = serialization::DECL_RECORD;
490 }
491 
492 void ASTDeclWriter::VisitValueDecl(ValueDecl *D) {
493   VisitNamedDecl(D);
494   Record.AddTypeRef(D->getType());
495 }
496 
497 void ASTDeclWriter::VisitEnumConstantDecl(EnumConstantDecl *D) {
498   VisitValueDecl(D);
499   Record.push_back(D->getInitExpr()? 1 : 0);
500   if (D->getInitExpr())
501     Record.AddStmt(D->getInitExpr());
502   Record.AddAPSInt(D->getInitVal());
503 
504   Code = serialization::DECL_ENUM_CONSTANT;
505 }
506 
507 void ASTDeclWriter::VisitDeclaratorDecl(DeclaratorDecl *D) {
508   VisitValueDecl(D);
509   Record.AddSourceLocation(D->getInnerLocStart());
510   Record.push_back(D->hasExtInfo());
511   if (D->hasExtInfo())
512     Record.AddQualifierInfo(*D->getExtInfo());
513 }
514 
515 void ASTDeclWriter::VisitFunctionDecl(FunctionDecl *D) {
516   VisitRedeclarable(D);
517   VisitDeclaratorDecl(D);
518   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
519   Record.push_back(D->getIdentifierNamespace());
520 
521   // FunctionDecl's body is handled last at ASTWriterDecl::Visit,
522   // after everything else is written.
523 
524   Record.push_back((int)D->SClass); // FIXME: stable encoding
525   Record.push_back(D->IsInline);
526   Record.push_back(D->IsInlineSpecified);
527   Record.push_back(D->IsExplicitSpecified);
528   Record.push_back(D->IsVirtualAsWritten);
529   Record.push_back(D->IsPure);
530   Record.push_back(D->HasInheritedPrototype);
531   Record.push_back(D->HasWrittenPrototype);
532   Record.push_back(D->IsDeleted);
533   Record.push_back(D->IsTrivial);
534   Record.push_back(D->IsTrivialForCall);
535   Record.push_back(D->IsDefaulted);
536   Record.push_back(D->IsExplicitlyDefaulted);
537   Record.push_back(D->HasImplicitReturnZero);
538   Record.push_back(D->IsConstexpr);
539   Record.push_back(D->UsesSEHTry);
540   Record.push_back(D->HasSkippedBody);
541   Record.push_back(D->IsMultiVersion);
542   Record.push_back(D->IsLateTemplateParsed);
543   Record.push_back(D->getLinkageInternal());
544   Record.AddSourceLocation(D->getLocEnd());
545 
546   Record.push_back(D->getODRHash());
547 
548   Record.push_back(D->getTemplatedKind());
549   switch (D->getTemplatedKind()) {
550   case FunctionDecl::TK_NonTemplate:
551     break;
552   case FunctionDecl::TK_FunctionTemplate:
553     Record.AddDeclRef(D->getDescribedFunctionTemplate());
554     break;
555   case FunctionDecl::TK_MemberSpecialization: {
556     MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo();
557     Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
558     Record.push_back(MemberInfo->getTemplateSpecializationKind());
559     Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
560     break;
561   }
562   case FunctionDecl::TK_FunctionTemplateSpecialization: {
563     FunctionTemplateSpecializationInfo *
564       FTSInfo = D->getTemplateSpecializationInfo();
565 
566     RegisterTemplateSpecialization(FTSInfo->getTemplate(), D);
567 
568     Record.AddDeclRef(FTSInfo->getTemplate());
569     Record.push_back(FTSInfo->getTemplateSpecializationKind());
570 
571     // Template arguments.
572     Record.AddTemplateArgumentList(FTSInfo->TemplateArguments);
573 
574     // Template args as written.
575     Record.push_back(FTSInfo->TemplateArgumentsAsWritten != nullptr);
576     if (FTSInfo->TemplateArgumentsAsWritten) {
577       Record.push_back(FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs);
578       for (int i=0, e = FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs;
579              i!=e; ++i)
580         Record.AddTemplateArgumentLoc(
581             (*FTSInfo->TemplateArgumentsAsWritten)[i]);
582       Record.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->LAngleLoc);
583       Record.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->RAngleLoc);
584     }
585 
586     Record.AddSourceLocation(FTSInfo->getPointOfInstantiation());
587 
588     if (D->isCanonicalDecl()) {
589       // Write the template that contains the specializations set. We will
590       // add a FunctionTemplateSpecializationInfo to it when reading.
591       Record.AddDeclRef(FTSInfo->getTemplate()->getCanonicalDecl());
592     }
593     break;
594   }
595   case FunctionDecl::TK_DependentFunctionTemplateSpecialization: {
596     DependentFunctionTemplateSpecializationInfo *
597       DFTSInfo = D->getDependentSpecializationInfo();
598 
599     // Templates.
600     Record.push_back(DFTSInfo->getNumTemplates());
601     for (int i=0, e = DFTSInfo->getNumTemplates(); i != e; ++i)
602       Record.AddDeclRef(DFTSInfo->getTemplate(i));
603 
604     // Templates args.
605     Record.push_back(DFTSInfo->getNumTemplateArgs());
606     for (int i=0, e = DFTSInfo->getNumTemplateArgs(); i != e; ++i)
607       Record.AddTemplateArgumentLoc(DFTSInfo->getTemplateArg(i));
608     Record.AddSourceLocation(DFTSInfo->getLAngleLoc());
609     Record.AddSourceLocation(DFTSInfo->getRAngleLoc());
610     break;
611   }
612   }
613 
614   Record.push_back(D->param_size());
615   for (auto P : D->parameters())
616     Record.AddDeclRef(P);
617   Code = serialization::DECL_FUNCTION;
618 }
619 
620 void ASTDeclWriter::VisitCXXDeductionGuideDecl(CXXDeductionGuideDecl *D) {
621   VisitFunctionDecl(D);
622   Record.push_back(D->IsCopyDeductionCandidate);
623   Code = serialization::DECL_CXX_DEDUCTION_GUIDE;
624 }
625 
626 void ASTDeclWriter::VisitObjCMethodDecl(ObjCMethodDecl *D) {
627   VisitNamedDecl(D);
628   // FIXME: convert to LazyStmtPtr?
629   // Unlike C/C++, method bodies will never be in header files.
630   bool HasBodyStuff = D->getBody() != nullptr     ||
631                       D->getSelfDecl() != nullptr || D->getCmdDecl() != nullptr;
632   Record.push_back(HasBodyStuff);
633   if (HasBodyStuff) {
634     Record.AddStmt(D->getBody());
635     Record.AddDeclRef(D->getSelfDecl());
636     Record.AddDeclRef(D->getCmdDecl());
637   }
638   Record.push_back(D->isInstanceMethod());
639   Record.push_back(D->isVariadic());
640   Record.push_back(D->isPropertyAccessor());
641   Record.push_back(D->isDefined());
642   Record.push_back(D->IsOverriding);
643   Record.push_back(D->HasSkippedBody);
644 
645   Record.push_back(D->IsRedeclaration);
646   Record.push_back(D->HasRedeclaration);
647   if (D->HasRedeclaration) {
648     assert(Context.getObjCMethodRedeclaration(D));
649     Record.AddDeclRef(Context.getObjCMethodRedeclaration(D));
650   }
651 
652   // FIXME: stable encoding for @required/@optional
653   Record.push_back(D->getImplementationControl());
654   // FIXME: stable encoding for in/out/inout/bycopy/byref/oneway/nullability
655   Record.push_back(D->getObjCDeclQualifier());
656   Record.push_back(D->hasRelatedResultType());
657   Record.AddTypeRef(D->getReturnType());
658   Record.AddTypeSourceInfo(D->getReturnTypeSourceInfo());
659   Record.AddSourceLocation(D->getLocEnd());
660   Record.push_back(D->param_size());
661   for (const auto *P : D->parameters())
662     Record.AddDeclRef(P);
663 
664   Record.push_back(D->SelLocsKind);
665   unsigned NumStoredSelLocs = D->getNumStoredSelLocs();
666   SourceLocation *SelLocs = D->getStoredSelLocs();
667   Record.push_back(NumStoredSelLocs);
668   for (unsigned i = 0; i != NumStoredSelLocs; ++i)
669     Record.AddSourceLocation(SelLocs[i]);
670 
671   Code = serialization::DECL_OBJC_METHOD;
672 }
673 
674 void ASTDeclWriter::VisitObjCTypeParamDecl(ObjCTypeParamDecl *D) {
675   VisitTypedefNameDecl(D);
676   Record.push_back(D->Variance);
677   Record.push_back(D->Index);
678   Record.AddSourceLocation(D->VarianceLoc);
679   Record.AddSourceLocation(D->ColonLoc);
680 
681   Code = serialization::DECL_OBJC_TYPE_PARAM;
682 }
683 
684 void ASTDeclWriter::VisitObjCContainerDecl(ObjCContainerDecl *D) {
685   VisitNamedDecl(D);
686   Record.AddSourceLocation(D->getAtStartLoc());
687   Record.AddSourceRange(D->getAtEndRange());
688   // Abstract class (no need to define a stable serialization::DECL code).
689 }
690 
691 void ASTDeclWriter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
692   VisitRedeclarable(D);
693   VisitObjCContainerDecl(D);
694   Record.AddTypeRef(QualType(D->getTypeForDecl(), 0));
695   AddObjCTypeParamList(D->TypeParamList);
696 
697   Record.push_back(D->isThisDeclarationADefinition());
698   if (D->isThisDeclarationADefinition()) {
699     // Write the DefinitionData
700     ObjCInterfaceDecl::DefinitionData &Data = D->data();
701 
702     Record.AddTypeSourceInfo(D->getSuperClassTInfo());
703     Record.AddSourceLocation(D->getEndOfDefinitionLoc());
704     Record.push_back(Data.HasDesignatedInitializers);
705 
706     // Write out the protocols that are directly referenced by the @interface.
707     Record.push_back(Data.ReferencedProtocols.size());
708     for (const auto *P : D->protocols())
709       Record.AddDeclRef(P);
710     for (const auto &PL : D->protocol_locs())
711       Record.AddSourceLocation(PL);
712 
713     // Write out the protocols that are transitively referenced.
714     Record.push_back(Data.AllReferencedProtocols.size());
715     for (ObjCList<ObjCProtocolDecl>::iterator
716               P = Data.AllReferencedProtocols.begin(),
717            PEnd = Data.AllReferencedProtocols.end();
718          P != PEnd; ++P)
719       Record.AddDeclRef(*P);
720 
721 
722     if (ObjCCategoryDecl *Cat = D->getCategoryListRaw()) {
723       // Ensure that we write out the set of categories for this class.
724       Writer.ObjCClassesWithCategories.insert(D);
725 
726       // Make sure that the categories get serialized.
727       for (; Cat; Cat = Cat->getNextClassCategoryRaw())
728         (void)Writer.GetDeclRef(Cat);
729     }
730   }
731 
732   Code = serialization::DECL_OBJC_INTERFACE;
733 }
734 
735 void ASTDeclWriter::VisitObjCIvarDecl(ObjCIvarDecl *D) {
736   VisitFieldDecl(D);
737   // FIXME: stable encoding for @public/@private/@protected/@package
738   Record.push_back(D->getAccessControl());
739   Record.push_back(D->getSynthesize());
740 
741   if (D->getDeclContext() == D->getLexicalDeclContext() &&
742       !D->hasAttrs() &&
743       !D->isImplicit() &&
744       !D->isUsed(false) &&
745       !D->isInvalidDecl() &&
746       !D->isReferenced() &&
747       !D->isModulePrivate() &&
748       !D->getBitWidth() &&
749       !D->hasExtInfo() &&
750       D->getDeclName())
751     AbbrevToUse = Writer.getDeclObjCIvarAbbrev();
752 
753   Code = serialization::DECL_OBJC_IVAR;
754 }
755 
756 void ASTDeclWriter::VisitObjCProtocolDecl(ObjCProtocolDecl *D) {
757   VisitRedeclarable(D);
758   VisitObjCContainerDecl(D);
759 
760   Record.push_back(D->isThisDeclarationADefinition());
761   if (D->isThisDeclarationADefinition()) {
762     Record.push_back(D->protocol_size());
763     for (const auto *I : D->protocols())
764       Record.AddDeclRef(I);
765     for (const auto &PL : D->protocol_locs())
766       Record.AddSourceLocation(PL);
767   }
768 
769   Code = serialization::DECL_OBJC_PROTOCOL;
770 }
771 
772 void ASTDeclWriter::VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D) {
773   VisitFieldDecl(D);
774   Code = serialization::DECL_OBJC_AT_DEFS_FIELD;
775 }
776 
777 void ASTDeclWriter::VisitObjCCategoryDecl(ObjCCategoryDecl *D) {
778   VisitObjCContainerDecl(D);
779   Record.AddSourceLocation(D->getCategoryNameLoc());
780   Record.AddSourceLocation(D->getIvarLBraceLoc());
781   Record.AddSourceLocation(D->getIvarRBraceLoc());
782   Record.AddDeclRef(D->getClassInterface());
783   AddObjCTypeParamList(D->TypeParamList);
784   Record.push_back(D->protocol_size());
785   for (const auto *I : D->protocols())
786     Record.AddDeclRef(I);
787   for (const auto &PL : D->protocol_locs())
788     Record.AddSourceLocation(PL);
789   Code = serialization::DECL_OBJC_CATEGORY;
790 }
791 
792 void ASTDeclWriter::VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D) {
793   VisitNamedDecl(D);
794   Record.AddDeclRef(D->getClassInterface());
795   Code = serialization::DECL_OBJC_COMPATIBLE_ALIAS;
796 }
797 
798 void ASTDeclWriter::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
799   VisitNamedDecl(D);
800   Record.AddSourceLocation(D->getAtLoc());
801   Record.AddSourceLocation(D->getLParenLoc());
802   Record.AddTypeRef(D->getType());
803   Record.AddTypeSourceInfo(D->getTypeSourceInfo());
804   // FIXME: stable encoding
805   Record.push_back((unsigned)D->getPropertyAttributes());
806   Record.push_back((unsigned)D->getPropertyAttributesAsWritten());
807   // FIXME: stable encoding
808   Record.push_back((unsigned)D->getPropertyImplementation());
809   Record.AddDeclarationName(D->getGetterName());
810   Record.AddSourceLocation(D->getGetterNameLoc());
811   Record.AddDeclarationName(D->getSetterName());
812   Record.AddSourceLocation(D->getSetterNameLoc());
813   Record.AddDeclRef(D->getGetterMethodDecl());
814   Record.AddDeclRef(D->getSetterMethodDecl());
815   Record.AddDeclRef(D->getPropertyIvarDecl());
816   Code = serialization::DECL_OBJC_PROPERTY;
817 }
818 
819 void ASTDeclWriter::VisitObjCImplDecl(ObjCImplDecl *D) {
820   VisitObjCContainerDecl(D);
821   Record.AddDeclRef(D->getClassInterface());
822   // Abstract class (no need to define a stable serialization::DECL code).
823 }
824 
825 void ASTDeclWriter::VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D) {
826   VisitObjCImplDecl(D);
827   Record.AddSourceLocation(D->getCategoryNameLoc());
828   Code = serialization::DECL_OBJC_CATEGORY_IMPL;
829 }
830 
831 void ASTDeclWriter::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
832   VisitObjCImplDecl(D);
833   Record.AddDeclRef(D->getSuperClass());
834   Record.AddSourceLocation(D->getSuperClassLoc());
835   Record.AddSourceLocation(D->getIvarLBraceLoc());
836   Record.AddSourceLocation(D->getIvarRBraceLoc());
837   Record.push_back(D->hasNonZeroConstructors());
838   Record.push_back(D->hasDestructors());
839   Record.push_back(D->NumIvarInitializers);
840   if (D->NumIvarInitializers)
841     Record.AddCXXCtorInitializers(
842         llvm::makeArrayRef(D->init_begin(), D->init_end()));
843   Code = serialization::DECL_OBJC_IMPLEMENTATION;
844 }
845 
846 void ASTDeclWriter::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
847   VisitDecl(D);
848   Record.AddSourceLocation(D->getLocStart());
849   Record.AddDeclRef(D->getPropertyDecl());
850   Record.AddDeclRef(D->getPropertyIvarDecl());
851   Record.AddSourceLocation(D->getPropertyIvarDeclLoc());
852   Record.AddStmt(D->getGetterCXXConstructor());
853   Record.AddStmt(D->getSetterCXXAssignment());
854   Code = serialization::DECL_OBJC_PROPERTY_IMPL;
855 }
856 
857 void ASTDeclWriter::VisitFieldDecl(FieldDecl *D) {
858   VisitDeclaratorDecl(D);
859   Record.push_back(D->isMutable());
860 
861   FieldDecl::InitStorageKind ISK = D->InitStorage.getInt();
862   Record.push_back(ISK);
863   if (ISK == FieldDecl::ISK_CapturedVLAType)
864     Record.AddTypeRef(QualType(D->getCapturedVLAType(), 0));
865   else if (ISK)
866     Record.AddStmt(D->getInClassInitializer());
867 
868   Record.AddStmt(D->getBitWidth());
869 
870   if (!D->getDeclName())
871     Record.AddDeclRef(Context.getInstantiatedFromUnnamedFieldDecl(D));
872 
873   if (D->getDeclContext() == D->getLexicalDeclContext() &&
874       !D->hasAttrs() &&
875       !D->isImplicit() &&
876       !D->isUsed(false) &&
877       !D->isInvalidDecl() &&
878       !D->isReferenced() &&
879       !D->isTopLevelDeclInObjCContainer() &&
880       !D->isModulePrivate() &&
881       !D->getBitWidth() &&
882       !D->hasInClassInitializer() &&
883       !D->hasCapturedVLAType() &&
884       !D->hasExtInfo() &&
885       !ObjCIvarDecl::classofKind(D->getKind()) &&
886       !ObjCAtDefsFieldDecl::classofKind(D->getKind()) &&
887       D->getDeclName())
888     AbbrevToUse = Writer.getDeclFieldAbbrev();
889 
890   Code = serialization::DECL_FIELD;
891 }
892 
893 void ASTDeclWriter::VisitMSPropertyDecl(MSPropertyDecl *D) {
894   VisitDeclaratorDecl(D);
895   Record.AddIdentifierRef(D->getGetterId());
896   Record.AddIdentifierRef(D->getSetterId());
897   Code = serialization::DECL_MS_PROPERTY;
898 }
899 
900 void ASTDeclWriter::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
901   VisitValueDecl(D);
902   Record.push_back(D->getChainingSize());
903 
904   for (const auto *P : D->chain())
905     Record.AddDeclRef(P);
906   Code = serialization::DECL_INDIRECTFIELD;
907 }
908 
909 void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
910   VisitRedeclarable(D);
911   VisitDeclaratorDecl(D);
912   Record.push_back(D->getStorageClass());
913   Record.push_back(D->getTSCSpec());
914   Record.push_back(D->getInitStyle());
915   if (!isa<ParmVarDecl>(D)) {
916     Record.push_back(D->isThisDeclarationADemotedDefinition());
917     Record.push_back(D->isExceptionVariable());
918     Record.push_back(D->isNRVOVariable());
919     Record.push_back(D->isCXXForRangeDecl());
920     Record.push_back(D->isARCPseudoStrong());
921     Record.push_back(D->isInline());
922     Record.push_back(D->isInlineSpecified());
923     Record.push_back(D->isConstexpr());
924     Record.push_back(D->isInitCapture());
925     Record.push_back(D->isPreviousDeclInSameBlockScope());
926     if (const auto *IPD = dyn_cast<ImplicitParamDecl>(D))
927       Record.push_back(static_cast<unsigned>(IPD->getParameterKind()));
928     else
929       Record.push_back(0);
930   }
931   Record.push_back(D->getLinkageInternal());
932 
933   if (D->getInit()) {
934     Record.push_back(!D->isInitKnownICE() ? 1 : (D->isInitICE() ? 3 : 2));
935     Record.AddStmt(D->getInit());
936   } else {
937     Record.push_back(0);
938   }
939 
940   if (D->getStorageDuration() == SD_Static) {
941     bool ModulesCodegen = false;
942     if (Writer.WritingModule &&
943         !D->getDescribedVarTemplate() && !D->getMemberSpecializationInfo() &&
944         !isa<VarTemplateSpecializationDecl>(D)) {
945       // When building a C++ Modules TS module interface unit, a strong
946       // definition in the module interface is provided by the compilation of
947       // that module interface unit, not by its users. (Inline variables are
948       // still emitted in module users.)
949       ModulesCodegen =
950           (Writer.WritingModule->Kind == Module::ModuleInterfaceUnit &&
951            Writer.Context->GetGVALinkageForVariable(D) == GVA_StrongExternal);
952     }
953     Record.push_back(ModulesCodegen);
954     if (ModulesCodegen)
955       Writer.ModularCodegenDecls.push_back(Writer.GetDeclRef(D));
956   }
957 
958   enum {
959     VarNotTemplate = 0, VarTemplate, StaticDataMemberSpecialization
960   };
961   if (VarTemplateDecl *TemplD = D->getDescribedVarTemplate()) {
962     Record.push_back(VarTemplate);
963     Record.AddDeclRef(TemplD);
964   } else if (MemberSpecializationInfo *SpecInfo
965                = D->getMemberSpecializationInfo()) {
966     Record.push_back(StaticDataMemberSpecialization);
967     Record.AddDeclRef(SpecInfo->getInstantiatedFrom());
968     Record.push_back(SpecInfo->getTemplateSpecializationKind());
969     Record.AddSourceLocation(SpecInfo->getPointOfInstantiation());
970   } else {
971     Record.push_back(VarNotTemplate);
972   }
973 
974   if (D->getDeclContext() == D->getLexicalDeclContext() &&
975       !D->hasAttrs() &&
976       !D->isImplicit() &&
977       !D->isUsed(false) &&
978       !D->isInvalidDecl() &&
979       !D->isReferenced() &&
980       !D->isTopLevelDeclInObjCContainer() &&
981       D->getAccess() == AS_none &&
982       !D->isModulePrivate() &&
983       !needsAnonymousDeclarationNumber(D) &&
984       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
985       !D->hasExtInfo() &&
986       D->getFirstDecl() == D->getMostRecentDecl() &&
987       D->getKind() == Decl::Var &&
988       !D->isInline() &&
989       !D->isConstexpr() &&
990       !D->isInitCapture() &&
991       !D->isPreviousDeclInSameBlockScope() &&
992       D->getStorageDuration() != SD_Static &&
993       !D->getMemberSpecializationInfo())
994     AbbrevToUse = Writer.getDeclVarAbbrev();
995 
996   Code = serialization::DECL_VAR;
997 }
998 
999 void ASTDeclWriter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
1000   VisitVarDecl(D);
1001   Code = serialization::DECL_IMPLICIT_PARAM;
1002 }
1003 
1004 void ASTDeclWriter::VisitParmVarDecl(ParmVarDecl *D) {
1005   VisitVarDecl(D);
1006   Record.push_back(D->isObjCMethodParameter());
1007   Record.push_back(D->getFunctionScopeDepth());
1008   Record.push_back(D->getFunctionScopeIndex());
1009   Record.push_back(D->getObjCDeclQualifier()); // FIXME: stable encoding
1010   Record.push_back(D->isKNRPromoted());
1011   Record.push_back(D->hasInheritedDefaultArg());
1012   Record.push_back(D->hasUninstantiatedDefaultArg());
1013   if (D->hasUninstantiatedDefaultArg())
1014     Record.AddStmt(D->getUninstantiatedDefaultArg());
1015   Code = serialization::DECL_PARM_VAR;
1016 
1017   assert(!D->isARCPseudoStrong()); // can be true of ImplicitParamDecl
1018 
1019   // If the assumptions about the DECL_PARM_VAR abbrev are true, use it.  Here
1020   // we dynamically check for the properties that we optimize for, but don't
1021   // know are true of all PARM_VAR_DECLs.
1022   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1023       !D->hasAttrs() &&
1024       !D->hasExtInfo() &&
1025       !D->isImplicit() &&
1026       !D->isUsed(false) &&
1027       !D->isInvalidDecl() &&
1028       !D->isReferenced() &&
1029       D->getAccess() == AS_none &&
1030       !D->isModulePrivate() &&
1031       D->getStorageClass() == 0 &&
1032       D->getInitStyle() == VarDecl::CInit && // Can params have anything else?
1033       D->getFunctionScopeDepth() == 0 &&
1034       D->getObjCDeclQualifier() == 0 &&
1035       !D->isKNRPromoted() &&
1036       !D->hasInheritedDefaultArg() &&
1037       D->getInit() == nullptr &&
1038       !D->hasUninstantiatedDefaultArg())  // No default expr.
1039     AbbrevToUse = Writer.getDeclParmVarAbbrev();
1040 
1041   // Check things we know are true of *every* PARM_VAR_DECL, which is more than
1042   // just us assuming it.
1043   assert(!D->getTSCSpec() && "PARM_VAR_DECL can't use TLS");
1044   assert(!D->isThisDeclarationADemotedDefinition()
1045          && "PARM_VAR_DECL can't be demoted definition.");
1046   assert(D->getAccess() == AS_none && "PARM_VAR_DECL can't be public/private");
1047   assert(!D->isExceptionVariable() && "PARM_VAR_DECL can't be exception var");
1048   assert(D->getPreviousDecl() == nullptr && "PARM_VAR_DECL can't be redecl");
1049   assert(!D->isStaticDataMember() &&
1050          "PARM_VAR_DECL can't be static data member");
1051 }
1052 
1053 void ASTDeclWriter::VisitDecompositionDecl(DecompositionDecl *D) {
1054   // Record the number of bindings first to simplify deserialization.
1055   Record.push_back(D->bindings().size());
1056 
1057   VisitVarDecl(D);
1058   for (auto *B : D->bindings())
1059     Record.AddDeclRef(B);
1060   Code = serialization::DECL_DECOMPOSITION;
1061 }
1062 
1063 void ASTDeclWriter::VisitBindingDecl(BindingDecl *D) {
1064   VisitValueDecl(D);
1065   Record.AddStmt(D->getBinding());
1066   Code = serialization::DECL_BINDING;
1067 }
1068 
1069 void ASTDeclWriter::VisitFileScopeAsmDecl(FileScopeAsmDecl *D) {
1070   VisitDecl(D);
1071   Record.AddStmt(D->getAsmString());
1072   Record.AddSourceLocation(D->getRParenLoc());
1073   Code = serialization::DECL_FILE_SCOPE_ASM;
1074 }
1075 
1076 void ASTDeclWriter::VisitEmptyDecl(EmptyDecl *D) {
1077   VisitDecl(D);
1078   Code = serialization::DECL_EMPTY;
1079 }
1080 
1081 void ASTDeclWriter::VisitBlockDecl(BlockDecl *D) {
1082   VisitDecl(D);
1083   Record.AddStmt(D->getBody());
1084   Record.AddTypeSourceInfo(D->getSignatureAsWritten());
1085   Record.push_back(D->param_size());
1086   for (ParmVarDecl *P : D->parameters())
1087     Record.AddDeclRef(P);
1088   Record.push_back(D->isVariadic());
1089   Record.push_back(D->blockMissingReturnType());
1090   Record.push_back(D->isConversionFromLambda());
1091   Record.push_back(D->capturesCXXThis());
1092   Record.push_back(D->getNumCaptures());
1093   for (const auto &capture : D->captures()) {
1094     Record.AddDeclRef(capture.getVariable());
1095 
1096     unsigned flags = 0;
1097     if (capture.isByRef()) flags |= 1;
1098     if (capture.isNested()) flags |= 2;
1099     if (capture.hasCopyExpr()) flags |= 4;
1100     Record.push_back(flags);
1101 
1102     if (capture.hasCopyExpr()) Record.AddStmt(capture.getCopyExpr());
1103   }
1104 
1105   Code = serialization::DECL_BLOCK;
1106 }
1107 
1108 void ASTDeclWriter::VisitCapturedDecl(CapturedDecl *CD) {
1109   Record.push_back(CD->getNumParams());
1110   VisitDecl(CD);
1111   Record.push_back(CD->getContextParamPosition());
1112   Record.push_back(CD->isNothrow() ? 1 : 0);
1113   // Body is stored by VisitCapturedStmt.
1114   for (unsigned I = 0; I < CD->getNumParams(); ++I)
1115     Record.AddDeclRef(CD->getParam(I));
1116   Code = serialization::DECL_CAPTURED;
1117 }
1118 
1119 void ASTDeclWriter::VisitLinkageSpecDecl(LinkageSpecDecl *D) {
1120   VisitDecl(D);
1121   Record.push_back(D->getLanguage());
1122   Record.AddSourceLocation(D->getExternLoc());
1123   Record.AddSourceLocation(D->getRBraceLoc());
1124   Code = serialization::DECL_LINKAGE_SPEC;
1125 }
1126 
1127 void ASTDeclWriter::VisitExportDecl(ExportDecl *D) {
1128   VisitDecl(D);
1129   Record.AddSourceLocation(D->getRBraceLoc());
1130   Code = serialization::DECL_EXPORT;
1131 }
1132 
1133 void ASTDeclWriter::VisitLabelDecl(LabelDecl *D) {
1134   VisitNamedDecl(D);
1135   Record.AddSourceLocation(D->getLocStart());
1136   Code = serialization::DECL_LABEL;
1137 }
1138 
1139 
1140 void ASTDeclWriter::VisitNamespaceDecl(NamespaceDecl *D) {
1141   VisitRedeclarable(D);
1142   VisitNamedDecl(D);
1143   Record.push_back(D->isInline());
1144   Record.AddSourceLocation(D->getLocStart());
1145   Record.AddSourceLocation(D->getRBraceLoc());
1146 
1147   if (D->isOriginalNamespace())
1148     Record.AddDeclRef(D->getAnonymousNamespace());
1149   Code = serialization::DECL_NAMESPACE;
1150 
1151   if (Writer.hasChain() && D->isAnonymousNamespace() &&
1152       D == D->getMostRecentDecl()) {
1153     // This is a most recent reopening of the anonymous namespace. If its parent
1154     // is in a previous PCH (or is the TU), mark that parent for update, because
1155     // the original namespace always points to the latest re-opening of its
1156     // anonymous namespace.
1157     Decl *Parent = cast<Decl>(
1158         D->getParent()->getRedeclContext()->getPrimaryContext());
1159     if (Parent->isFromASTFile() || isa<TranslationUnitDecl>(Parent)) {
1160       Writer.DeclUpdates[Parent].push_back(
1161           ASTWriter::DeclUpdate(UPD_CXX_ADDED_ANONYMOUS_NAMESPACE, D));
1162     }
1163   }
1164 }
1165 
1166 void ASTDeclWriter::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
1167   VisitRedeclarable(D);
1168   VisitNamedDecl(D);
1169   Record.AddSourceLocation(D->getNamespaceLoc());
1170   Record.AddSourceLocation(D->getTargetNameLoc());
1171   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1172   Record.AddDeclRef(D->getNamespace());
1173   Code = serialization::DECL_NAMESPACE_ALIAS;
1174 }
1175 
1176 void ASTDeclWriter::VisitUsingDecl(UsingDecl *D) {
1177   VisitNamedDecl(D);
1178   Record.AddSourceLocation(D->getUsingLoc());
1179   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1180   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
1181   Record.AddDeclRef(D->FirstUsingShadow.getPointer());
1182   Record.push_back(D->hasTypename());
1183   Record.AddDeclRef(Context.getInstantiatedFromUsingDecl(D));
1184   Code = serialization::DECL_USING;
1185 }
1186 
1187 void ASTDeclWriter::VisitUsingPackDecl(UsingPackDecl *D) {
1188   Record.push_back(D->NumExpansions);
1189   VisitNamedDecl(D);
1190   Record.AddDeclRef(D->getInstantiatedFromUsingDecl());
1191   for (auto *E : D->expansions())
1192     Record.AddDeclRef(E);
1193   Code = serialization::DECL_USING_PACK;
1194 }
1195 
1196 void ASTDeclWriter::VisitUsingShadowDecl(UsingShadowDecl *D) {
1197   VisitRedeclarable(D);
1198   VisitNamedDecl(D);
1199   Record.AddDeclRef(D->getTargetDecl());
1200   Record.push_back(D->getIdentifierNamespace());
1201   Record.AddDeclRef(D->UsingOrNextShadow);
1202   Record.AddDeclRef(Context.getInstantiatedFromUsingShadowDecl(D));
1203   Code = serialization::DECL_USING_SHADOW;
1204 }
1205 
1206 void ASTDeclWriter::VisitConstructorUsingShadowDecl(
1207     ConstructorUsingShadowDecl *D) {
1208   VisitUsingShadowDecl(D);
1209   Record.AddDeclRef(D->NominatedBaseClassShadowDecl);
1210   Record.AddDeclRef(D->ConstructedBaseClassShadowDecl);
1211   Record.push_back(D->IsVirtual);
1212   Code = serialization::DECL_CONSTRUCTOR_USING_SHADOW;
1213 }
1214 
1215 void ASTDeclWriter::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1216   VisitNamedDecl(D);
1217   Record.AddSourceLocation(D->getUsingLoc());
1218   Record.AddSourceLocation(D->getNamespaceKeyLocation());
1219   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1220   Record.AddDeclRef(D->getNominatedNamespace());
1221   Record.AddDeclRef(dyn_cast<Decl>(D->getCommonAncestor()));
1222   Code = serialization::DECL_USING_DIRECTIVE;
1223 }
1224 
1225 void ASTDeclWriter::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1226   VisitValueDecl(D);
1227   Record.AddSourceLocation(D->getUsingLoc());
1228   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1229   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
1230   Record.AddSourceLocation(D->getEllipsisLoc());
1231   Code = serialization::DECL_UNRESOLVED_USING_VALUE;
1232 }
1233 
1234 void ASTDeclWriter::VisitUnresolvedUsingTypenameDecl(
1235                                                UnresolvedUsingTypenameDecl *D) {
1236   VisitTypeDecl(D);
1237   Record.AddSourceLocation(D->getTypenameLoc());
1238   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1239   Record.AddSourceLocation(D->getEllipsisLoc());
1240   Code = serialization::DECL_UNRESOLVED_USING_TYPENAME;
1241 }
1242 
1243 void ASTDeclWriter::VisitCXXRecordDecl(CXXRecordDecl *D) {
1244   VisitRecordDecl(D);
1245 
1246   enum {
1247     CXXRecNotTemplate = 0, CXXRecTemplate, CXXRecMemberSpecialization
1248   };
1249   if (ClassTemplateDecl *TemplD = D->getDescribedClassTemplate()) {
1250     Record.push_back(CXXRecTemplate);
1251     Record.AddDeclRef(TemplD);
1252   } else if (MemberSpecializationInfo *MSInfo
1253                = D->getMemberSpecializationInfo()) {
1254     Record.push_back(CXXRecMemberSpecialization);
1255     Record.AddDeclRef(MSInfo->getInstantiatedFrom());
1256     Record.push_back(MSInfo->getTemplateSpecializationKind());
1257     Record.AddSourceLocation(MSInfo->getPointOfInstantiation());
1258   } else {
1259     Record.push_back(CXXRecNotTemplate);
1260   }
1261 
1262   Record.push_back(D->isThisDeclarationADefinition());
1263   if (D->isThisDeclarationADefinition())
1264     Record.AddCXXDefinitionData(D);
1265 
1266   // Store (what we currently believe to be) the key function to avoid
1267   // deserializing every method so we can compute it.
1268   if (D->IsCompleteDefinition)
1269     Record.AddDeclRef(Context.getCurrentKeyFunction(D));
1270 
1271   Code = serialization::DECL_CXX_RECORD;
1272 }
1273 
1274 void ASTDeclWriter::VisitCXXMethodDecl(CXXMethodDecl *D) {
1275   VisitFunctionDecl(D);
1276   if (D->isCanonicalDecl()) {
1277     Record.push_back(D->size_overridden_methods());
1278     for (const CXXMethodDecl *MD : D->overridden_methods())
1279       Record.AddDeclRef(MD);
1280   } else {
1281     // We only need to record overridden methods once for the canonical decl.
1282     Record.push_back(0);
1283   }
1284 
1285   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1286       D->getFirstDecl() == D->getMostRecentDecl() &&
1287       !D->isInvalidDecl() &&
1288       !D->hasAttrs() &&
1289       !D->isTopLevelDeclInObjCContainer() &&
1290       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1291       !D->hasExtInfo() &&
1292       !D->hasInheritedPrototype() &&
1293       D->hasWrittenPrototype())
1294     AbbrevToUse = Writer.getDeclCXXMethodAbbrev();
1295 
1296   Code = serialization::DECL_CXX_METHOD;
1297 }
1298 
1299 void ASTDeclWriter::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1300   if (auto Inherited = D->getInheritedConstructor()) {
1301     Record.AddDeclRef(Inherited.getShadowDecl());
1302     Record.AddDeclRef(Inherited.getConstructor());
1303     Code = serialization::DECL_CXX_INHERITED_CONSTRUCTOR;
1304   } else {
1305     Code = serialization::DECL_CXX_CONSTRUCTOR;
1306   }
1307 
1308   VisitCXXMethodDecl(D);
1309 
1310   Code = D->isInheritingConstructor()
1311              ? serialization::DECL_CXX_INHERITED_CONSTRUCTOR
1312              : serialization::DECL_CXX_CONSTRUCTOR;
1313 }
1314 
1315 void ASTDeclWriter::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1316   VisitCXXMethodDecl(D);
1317 
1318   Record.AddDeclRef(D->getOperatorDelete());
1319   if (D->getOperatorDelete())
1320     Record.AddStmt(D->getOperatorDeleteThisArg());
1321 
1322   Code = serialization::DECL_CXX_DESTRUCTOR;
1323 }
1324 
1325 void ASTDeclWriter::VisitCXXConversionDecl(CXXConversionDecl *D) {
1326   VisitCXXMethodDecl(D);
1327   Code = serialization::DECL_CXX_CONVERSION;
1328 }
1329 
1330 void ASTDeclWriter::VisitImportDecl(ImportDecl *D) {
1331   VisitDecl(D);
1332   Record.push_back(Writer.getSubmoduleID(D->getImportedModule()));
1333   ArrayRef<SourceLocation> IdentifierLocs = D->getIdentifierLocs();
1334   Record.push_back(!IdentifierLocs.empty());
1335   if (IdentifierLocs.empty()) {
1336     Record.AddSourceLocation(D->getLocEnd());
1337     Record.push_back(1);
1338   } else {
1339     for (unsigned I = 0, N = IdentifierLocs.size(); I != N; ++I)
1340       Record.AddSourceLocation(IdentifierLocs[I]);
1341     Record.push_back(IdentifierLocs.size());
1342   }
1343   // Note: the number of source locations must always be the last element in
1344   // the record.
1345   Code = serialization::DECL_IMPORT;
1346 }
1347 
1348 void ASTDeclWriter::VisitAccessSpecDecl(AccessSpecDecl *D) {
1349   VisitDecl(D);
1350   Record.AddSourceLocation(D->getColonLoc());
1351   Code = serialization::DECL_ACCESS_SPEC;
1352 }
1353 
1354 void ASTDeclWriter::VisitFriendDecl(FriendDecl *D) {
1355   // Record the number of friend type template parameter lists here
1356   // so as to simplify memory allocation during deserialization.
1357   Record.push_back(D->NumTPLists);
1358   VisitDecl(D);
1359   bool hasFriendDecl = D->Friend.is<NamedDecl*>();
1360   Record.push_back(hasFriendDecl);
1361   if (hasFriendDecl)
1362     Record.AddDeclRef(D->getFriendDecl());
1363   else
1364     Record.AddTypeSourceInfo(D->getFriendType());
1365   for (unsigned i = 0; i < D->NumTPLists; ++i)
1366     Record.AddTemplateParameterList(D->getFriendTypeTemplateParameterList(i));
1367   Record.AddDeclRef(D->getNextFriend());
1368   Record.push_back(D->UnsupportedFriend);
1369   Record.AddSourceLocation(D->FriendLoc);
1370   Code = serialization::DECL_FRIEND;
1371 }
1372 
1373 void ASTDeclWriter::VisitFriendTemplateDecl(FriendTemplateDecl *D) {
1374   VisitDecl(D);
1375   Record.push_back(D->getNumTemplateParameters());
1376   for (unsigned i = 0, e = D->getNumTemplateParameters(); i != e; ++i)
1377     Record.AddTemplateParameterList(D->getTemplateParameterList(i));
1378   Record.push_back(D->getFriendDecl() != nullptr);
1379   if (D->getFriendDecl())
1380     Record.AddDeclRef(D->getFriendDecl());
1381   else
1382     Record.AddTypeSourceInfo(D->getFriendType());
1383   Record.AddSourceLocation(D->getFriendLoc());
1384   Code = serialization::DECL_FRIEND_TEMPLATE;
1385 }
1386 
1387 void ASTDeclWriter::VisitTemplateDecl(TemplateDecl *D) {
1388   VisitNamedDecl(D);
1389 
1390   Record.AddDeclRef(D->getTemplatedDecl());
1391   Record.AddTemplateParameterList(D->getTemplateParameters());
1392 }
1393 
1394 void ASTDeclWriter::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
1395   VisitRedeclarable(D);
1396 
1397   // Emit data to initialize CommonOrPrev before VisitTemplateDecl so that
1398   // getCommonPtr() can be used while this is still initializing.
1399   if (D->isFirstDecl()) {
1400     // This declaration owns the 'common' pointer, so serialize that data now.
1401     Record.AddDeclRef(D->getInstantiatedFromMemberTemplate());
1402     if (D->getInstantiatedFromMemberTemplate())
1403       Record.push_back(D->isMemberSpecialization());
1404   }
1405 
1406   VisitTemplateDecl(D);
1407   Record.push_back(D->getIdentifierNamespace());
1408 }
1409 
1410 void ASTDeclWriter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
1411   VisitRedeclarableTemplateDecl(D);
1412 
1413   if (D->isFirstDecl())
1414     AddTemplateSpecializations(D);
1415   Code = serialization::DECL_CLASS_TEMPLATE;
1416 }
1417 
1418 void ASTDeclWriter::VisitClassTemplateSpecializationDecl(
1419                                            ClassTemplateSpecializationDecl *D) {
1420   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1421 
1422   VisitCXXRecordDecl(D);
1423 
1424   llvm::PointerUnion<ClassTemplateDecl *,
1425                      ClassTemplatePartialSpecializationDecl *> InstFrom
1426     = D->getSpecializedTemplateOrPartial();
1427   if (Decl *InstFromD = InstFrom.dyn_cast<ClassTemplateDecl *>()) {
1428     Record.AddDeclRef(InstFromD);
1429   } else {
1430     Record.AddDeclRef(InstFrom.get<ClassTemplatePartialSpecializationDecl *>());
1431     Record.AddTemplateArgumentList(&D->getTemplateInstantiationArgs());
1432   }
1433 
1434   Record.AddTemplateArgumentList(&D->getTemplateArgs());
1435   Record.AddSourceLocation(D->getPointOfInstantiation());
1436   Record.push_back(D->getSpecializationKind());
1437   Record.push_back(D->isCanonicalDecl());
1438 
1439   if (D->isCanonicalDecl()) {
1440     // When reading, we'll add it to the folding set of the following template.
1441     Record.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl());
1442   }
1443 
1444   // Explicit info.
1445   Record.AddTypeSourceInfo(D->getTypeAsWritten());
1446   if (D->getTypeAsWritten()) {
1447     Record.AddSourceLocation(D->getExternLoc());
1448     Record.AddSourceLocation(D->getTemplateKeywordLoc());
1449   }
1450 
1451   Code = serialization::DECL_CLASS_TEMPLATE_SPECIALIZATION;
1452 }
1453 
1454 void ASTDeclWriter::VisitClassTemplatePartialSpecializationDecl(
1455                                     ClassTemplatePartialSpecializationDecl *D) {
1456   VisitClassTemplateSpecializationDecl(D);
1457 
1458   Record.AddTemplateParameterList(D->getTemplateParameters());
1459   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1460 
1461   // These are read/set from/to the first declaration.
1462   if (D->getPreviousDecl() == nullptr) {
1463     Record.AddDeclRef(D->getInstantiatedFromMember());
1464     Record.push_back(D->isMemberSpecialization());
1465   }
1466 
1467   Code = serialization::DECL_CLASS_TEMPLATE_PARTIAL_SPECIALIZATION;
1468 }
1469 
1470 void ASTDeclWriter::VisitVarTemplateDecl(VarTemplateDecl *D) {
1471   VisitRedeclarableTemplateDecl(D);
1472 
1473   if (D->isFirstDecl())
1474     AddTemplateSpecializations(D);
1475   Code = serialization::DECL_VAR_TEMPLATE;
1476 }
1477 
1478 void ASTDeclWriter::VisitVarTemplateSpecializationDecl(
1479     VarTemplateSpecializationDecl *D) {
1480   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1481 
1482   VisitVarDecl(D);
1483 
1484   llvm::PointerUnion<VarTemplateDecl *, VarTemplatePartialSpecializationDecl *>
1485   InstFrom = D->getSpecializedTemplateOrPartial();
1486   if (Decl *InstFromD = InstFrom.dyn_cast<VarTemplateDecl *>()) {
1487     Record.AddDeclRef(InstFromD);
1488   } else {
1489     Record.AddDeclRef(InstFrom.get<VarTemplatePartialSpecializationDecl *>());
1490     Record.AddTemplateArgumentList(&D->getTemplateInstantiationArgs());
1491   }
1492 
1493   // Explicit info.
1494   Record.AddTypeSourceInfo(D->getTypeAsWritten());
1495   if (D->getTypeAsWritten()) {
1496     Record.AddSourceLocation(D->getExternLoc());
1497     Record.AddSourceLocation(D->getTemplateKeywordLoc());
1498   }
1499 
1500   Record.AddTemplateArgumentList(&D->getTemplateArgs());
1501   Record.AddSourceLocation(D->getPointOfInstantiation());
1502   Record.push_back(D->getSpecializationKind());
1503   Record.push_back(D->IsCompleteDefinition);
1504   Record.push_back(D->isCanonicalDecl());
1505 
1506   if (D->isCanonicalDecl()) {
1507     // When reading, we'll add it to the folding set of the following template.
1508     Record.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl());
1509   }
1510 
1511   Code = serialization::DECL_VAR_TEMPLATE_SPECIALIZATION;
1512 }
1513 
1514 void ASTDeclWriter::VisitVarTemplatePartialSpecializationDecl(
1515     VarTemplatePartialSpecializationDecl *D) {
1516   VisitVarTemplateSpecializationDecl(D);
1517 
1518   Record.AddTemplateParameterList(D->getTemplateParameters());
1519   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1520 
1521   // These are read/set from/to the first declaration.
1522   if (D->getPreviousDecl() == nullptr) {
1523     Record.AddDeclRef(D->getInstantiatedFromMember());
1524     Record.push_back(D->isMemberSpecialization());
1525   }
1526 
1527   Code = serialization::DECL_VAR_TEMPLATE_PARTIAL_SPECIALIZATION;
1528 }
1529 
1530 void ASTDeclWriter::VisitClassScopeFunctionSpecializationDecl(
1531                                     ClassScopeFunctionSpecializationDecl *D) {
1532   VisitDecl(D);
1533   Record.AddDeclRef(D->getSpecialization());
1534   Code = serialization::DECL_CLASS_SCOPE_FUNCTION_SPECIALIZATION;
1535 }
1536 
1537 
1538 void ASTDeclWriter::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
1539   VisitRedeclarableTemplateDecl(D);
1540 
1541   if (D->isFirstDecl())
1542     AddTemplateSpecializations(D);
1543   Code = serialization::DECL_FUNCTION_TEMPLATE;
1544 }
1545 
1546 void ASTDeclWriter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
1547   VisitTypeDecl(D);
1548 
1549   Record.push_back(D->wasDeclaredWithTypename());
1550 
1551   bool OwnsDefaultArg = D->hasDefaultArgument() &&
1552                         !D->defaultArgumentWasInherited();
1553   Record.push_back(OwnsDefaultArg);
1554   if (OwnsDefaultArg)
1555     Record.AddTypeSourceInfo(D->getDefaultArgumentInfo());
1556 
1557   Code = serialization::DECL_TEMPLATE_TYPE_PARM;
1558 }
1559 
1560 void ASTDeclWriter::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
1561   // For an expanded parameter pack, record the number of expansion types here
1562   // so that it's easier for deserialization to allocate the right amount of
1563   // memory.
1564   if (D->isExpandedParameterPack())
1565     Record.push_back(D->getNumExpansionTypes());
1566 
1567   VisitDeclaratorDecl(D);
1568   // TemplateParmPosition.
1569   Record.push_back(D->getDepth());
1570   Record.push_back(D->getPosition());
1571 
1572   if (D->isExpandedParameterPack()) {
1573     for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1574       Record.AddTypeRef(D->getExpansionType(I));
1575       Record.AddTypeSourceInfo(D->getExpansionTypeSourceInfo(I));
1576     }
1577 
1578     Code = serialization::DECL_EXPANDED_NON_TYPE_TEMPLATE_PARM_PACK;
1579   } else {
1580     // Rest of NonTypeTemplateParmDecl.
1581     Record.push_back(D->isParameterPack());
1582     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1583                           !D->defaultArgumentWasInherited();
1584     Record.push_back(OwnsDefaultArg);
1585     if (OwnsDefaultArg)
1586       Record.AddStmt(D->getDefaultArgument());
1587     Code = serialization::DECL_NON_TYPE_TEMPLATE_PARM;
1588   }
1589 }
1590 
1591 void ASTDeclWriter::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
1592   // For an expanded parameter pack, record the number of expansion types here
1593   // so that it's easier for deserialization to allocate the right amount of
1594   // memory.
1595   if (D->isExpandedParameterPack())
1596     Record.push_back(D->getNumExpansionTemplateParameters());
1597 
1598   VisitTemplateDecl(D);
1599   // TemplateParmPosition.
1600   Record.push_back(D->getDepth());
1601   Record.push_back(D->getPosition());
1602 
1603   if (D->isExpandedParameterPack()) {
1604     for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
1605          I != N; ++I)
1606       Record.AddTemplateParameterList(D->getExpansionTemplateParameters(I));
1607     Code = serialization::DECL_EXPANDED_TEMPLATE_TEMPLATE_PARM_PACK;
1608   } else {
1609     // Rest of TemplateTemplateParmDecl.
1610     Record.push_back(D->isParameterPack());
1611     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1612                           !D->defaultArgumentWasInherited();
1613     Record.push_back(OwnsDefaultArg);
1614     if (OwnsDefaultArg)
1615       Record.AddTemplateArgumentLoc(D->getDefaultArgument());
1616     Code = serialization::DECL_TEMPLATE_TEMPLATE_PARM;
1617   }
1618 }
1619 
1620 void ASTDeclWriter::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
1621   VisitRedeclarableTemplateDecl(D);
1622   Code = serialization::DECL_TYPE_ALIAS_TEMPLATE;
1623 }
1624 
1625 void ASTDeclWriter::VisitStaticAssertDecl(StaticAssertDecl *D) {
1626   VisitDecl(D);
1627   Record.AddStmt(D->getAssertExpr());
1628   Record.push_back(D->isFailed());
1629   Record.AddStmt(D->getMessage());
1630   Record.AddSourceLocation(D->getRParenLoc());
1631   Code = serialization::DECL_STATIC_ASSERT;
1632 }
1633 
1634 /// \brief Emit the DeclContext part of a declaration context decl.
1635 void ASTDeclWriter::VisitDeclContext(DeclContext *DC) {
1636   Record.AddOffset(Writer.WriteDeclContextLexicalBlock(Context, DC));
1637   Record.AddOffset(Writer.WriteDeclContextVisibleBlock(Context, DC));
1638 }
1639 
1640 const Decl *ASTWriter::getFirstLocalDecl(const Decl *D) {
1641   assert(IsLocalDecl(D) && "expected a local declaration");
1642 
1643   const Decl *Canon = D->getCanonicalDecl();
1644   if (IsLocalDecl(Canon))
1645     return Canon;
1646 
1647   const Decl *&CacheEntry = FirstLocalDeclCache[Canon];
1648   if (CacheEntry)
1649     return CacheEntry;
1650 
1651   for (const Decl *Redecl = D; Redecl; Redecl = Redecl->getPreviousDecl())
1652     if (IsLocalDecl(Redecl))
1653       D = Redecl;
1654   return CacheEntry = D;
1655 }
1656 
1657 template <typename T>
1658 void ASTDeclWriter::VisitRedeclarable(Redeclarable<T> *D) {
1659   T *First = D->getFirstDecl();
1660   T *MostRecent = First->getMostRecentDecl();
1661   T *DAsT = static_cast<T *>(D);
1662   if (MostRecent != First) {
1663     assert(isRedeclarableDeclKind(DAsT->getKind()) &&
1664            "Not considered redeclarable?");
1665 
1666     Record.AddDeclRef(First);
1667 
1668     // Write out a list of local redeclarations of this declaration if it's the
1669     // first local declaration in the chain.
1670     const Decl *FirstLocal = Writer.getFirstLocalDecl(DAsT);
1671     if (DAsT == FirstLocal) {
1672       // Emit a list of all imported first declarations so that we can be sure
1673       // that all redeclarations visible to this module are before D in the
1674       // redecl chain.
1675       unsigned I = Record.size();
1676       Record.push_back(0);
1677       if (Writer.Chain)
1678         AddFirstDeclFromEachModule(DAsT, /*IncludeLocal*/false);
1679       // This is the number of imported first declarations + 1.
1680       Record[I] = Record.size() - I;
1681 
1682       // Collect the set of local redeclarations of this declaration, from
1683       // newest to oldest.
1684       ASTWriter::RecordData LocalRedecls;
1685       ASTRecordWriter LocalRedeclWriter(Record, LocalRedecls);
1686       for (const Decl *Prev = FirstLocal->getMostRecentDecl();
1687            Prev != FirstLocal; Prev = Prev->getPreviousDecl())
1688         if (!Prev->isFromASTFile())
1689           LocalRedeclWriter.AddDeclRef(Prev);
1690 
1691       // If we have any redecls, write them now as a separate record preceding
1692       // the declaration itself.
1693       if (LocalRedecls.empty())
1694         Record.push_back(0);
1695       else
1696         Record.AddOffset(LocalRedeclWriter.Emit(LOCAL_REDECLARATIONS));
1697     } else {
1698       Record.push_back(0);
1699       Record.AddDeclRef(FirstLocal);
1700     }
1701 
1702     // Make sure that we serialize both the previous and the most-recent
1703     // declarations, which (transitively) ensures that all declarations in the
1704     // chain get serialized.
1705     //
1706     // FIXME: This is not correct; when we reach an imported declaration we
1707     // won't emit its previous declaration.
1708     (void)Writer.GetDeclRef(D->getPreviousDecl());
1709     (void)Writer.GetDeclRef(MostRecent);
1710   } else {
1711     // We use the sentinel value 0 to indicate an only declaration.
1712     Record.push_back(0);
1713   }
1714 }
1715 
1716 void ASTDeclWriter::VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D) {
1717   Record.push_back(D->varlist_size());
1718   VisitDecl(D);
1719   for (auto *I : D->varlists())
1720     Record.AddStmt(I);
1721   Code = serialization::DECL_OMP_THREADPRIVATE;
1722 }
1723 
1724 void ASTDeclWriter::VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D) {
1725   VisitValueDecl(D);
1726   Record.AddSourceLocation(D->getLocStart());
1727   Record.AddStmt(D->getCombiner());
1728   Record.AddStmt(D->getInitializer());
1729   Record.push_back(D->getInitializerKind());
1730   Record.AddDeclRef(D->getPrevDeclInScope());
1731   Code = serialization::DECL_OMP_DECLARE_REDUCTION;
1732 }
1733 
1734 void ASTDeclWriter::VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D) {
1735   VisitVarDecl(D);
1736   Code = serialization::DECL_OMP_CAPTUREDEXPR;
1737 }
1738 
1739 //===----------------------------------------------------------------------===//
1740 // ASTWriter Implementation
1741 //===----------------------------------------------------------------------===//
1742 
1743 void ASTWriter::WriteDeclAbbrevs() {
1744   using namespace llvm;
1745 
1746   std::shared_ptr<BitCodeAbbrev> Abv;
1747 
1748   // Abbreviation for DECL_FIELD
1749   Abv = std::make_shared<BitCodeAbbrev>();
1750   Abv->Add(BitCodeAbbrevOp(serialization::DECL_FIELD));
1751   // Decl
1752   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1753   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1754   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1755   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1756   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1757   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1758   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1759   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1760   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1761   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1762   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1763   // NamedDecl
1764   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1765   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1766   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1767   // ValueDecl
1768   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1769   // DeclaratorDecl
1770   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1771   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1772   // FieldDecl
1773   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1774   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
1775   // Type Source Info
1776   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1777   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1778   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1779   DeclFieldAbbrev = Stream.EmitAbbrev(std::move(Abv));
1780 
1781   // Abbreviation for DECL_OBJC_IVAR
1782   Abv = std::make_shared<BitCodeAbbrev>();
1783   Abv->Add(BitCodeAbbrevOp(serialization::DECL_OBJC_IVAR));
1784   // Decl
1785   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1786   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1787   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1788   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1789   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1790   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1791   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1792   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1793   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
1794   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1795   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1796   // NamedDecl
1797   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1798   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1799   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1800   // ValueDecl
1801   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1802   // DeclaratorDecl
1803   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1804   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1805   // FieldDecl
1806   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
1807   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
1808   // ObjC Ivar
1809   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getAccessControl
1810   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getSynthesize
1811   // Type Source Info
1812   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1813   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1814   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1815   DeclObjCIvarAbbrev = Stream.EmitAbbrev(std::move(Abv));
1816 
1817   // Abbreviation for DECL_ENUM
1818   Abv = std::make_shared<BitCodeAbbrev>();
1819   Abv->Add(BitCodeAbbrevOp(serialization::DECL_ENUM));
1820   // Redeclarable
1821   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1822   // Decl
1823   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1824   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1825   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1826   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1827   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1828   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1829   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1830   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1831   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1832   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1833   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1834   // NamedDecl
1835   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1836   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1837   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1838   // TypeDecl
1839   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1840   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1841   // TagDecl
1842   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
1843   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
1844   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
1845   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
1846   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
1847   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
1848   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1849   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1850   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
1851   // EnumDecl
1852   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddTypeRef
1853   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IntegerType
1854   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getPromotionType
1855   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumPositiveBits
1856   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumNegativeBits
1857   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScoped
1858   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScopedUsingClassTag
1859   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isFixed
1860   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InstantiatedMembEnum
1861   // DC
1862   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
1863   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
1864   DeclEnumAbbrev = Stream.EmitAbbrev(std::move(Abv));
1865 
1866   // Abbreviation for DECL_RECORD
1867   Abv = std::make_shared<BitCodeAbbrev>();
1868   Abv->Add(BitCodeAbbrevOp(serialization::DECL_RECORD));
1869   // Redeclarable
1870   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1871   // Decl
1872   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1873   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1874   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1875   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1876   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1877   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1878   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1879   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1880   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1881   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1882   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1883   // NamedDecl
1884   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1885   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1886   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1887   // TypeDecl
1888   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1889   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1890   // TagDecl
1891   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
1892   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
1893   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
1894   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
1895   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
1896   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
1897   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1898   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
1899   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
1900   // RecordDecl
1901   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // FlexibleArrayMember
1902   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // AnonymousStructUnion
1903   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasObjectMember
1904   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasVolatileMember
1905 
1906   // isNonTrivialToPrimitiveDefaultInitialize
1907   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1908   // isNonTrivialToPrimitiveCopy
1909   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1910   // isNonTrivialToPrimitiveDestroy
1911   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1912 
1913   // DC
1914   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
1915   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
1916   DeclRecordAbbrev = Stream.EmitAbbrev(std::move(Abv));
1917 
1918   // Abbreviation for DECL_PARM_VAR
1919   Abv = std::make_shared<BitCodeAbbrev>();
1920   Abv->Add(BitCodeAbbrevOp(serialization::DECL_PARM_VAR));
1921   // Redeclarable
1922   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1923   // Decl
1924   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1925   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1926   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1927   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1928   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1929   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
1930   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
1931   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1932   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
1933   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1934   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1935   // NamedDecl
1936   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1937   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1938   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1939   // ValueDecl
1940   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
1941   // DeclaratorDecl
1942   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
1943   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
1944   // VarDecl
1945   Abv->Add(BitCodeAbbrevOp(0));                       // SClass
1946   Abv->Add(BitCodeAbbrevOp(0));                       // TSCSpec
1947   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
1948   Abv->Add(BitCodeAbbrevOp(0));                       // Linkage
1949   Abv->Add(BitCodeAbbrevOp(0));                       // HasInit
1950   Abv->Add(BitCodeAbbrevOp(0));                   // HasMemberSpecializationInfo
1951   // ParmVarDecl
1952   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsObjCMethodParameter
1953   Abv->Add(BitCodeAbbrevOp(0));                       // ScopeDepth
1954   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ScopeIndex
1955   Abv->Add(BitCodeAbbrevOp(0));                       // ObjCDeclQualifier
1956   Abv->Add(BitCodeAbbrevOp(0));                       // KNRPromoted
1957   Abv->Add(BitCodeAbbrevOp(0));                       // HasInheritedDefaultArg
1958   Abv->Add(BitCodeAbbrevOp(0));                   // HasUninstantiatedDefaultArg
1959   // Type Source Info
1960   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1961   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1962   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1963   DeclParmVarAbbrev = Stream.EmitAbbrev(std::move(Abv));
1964 
1965   // Abbreviation for DECL_TYPEDEF
1966   Abv = std::make_shared<BitCodeAbbrev>();
1967   Abv->Add(BitCodeAbbrevOp(serialization::DECL_TYPEDEF));
1968   // Redeclarable
1969   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1970   // Decl
1971   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
1972   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
1973   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
1974   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
1975   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
1976   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isUsed
1977   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isReferenced
1978   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
1979   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // C++ AccessSpecifier
1980   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
1981   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
1982   // NamedDecl
1983   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
1984   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
1985   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
1986   // TypeDecl
1987   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
1988   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
1989   // TypedefDecl
1990   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1991   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
1992   DeclTypedefAbbrev = Stream.EmitAbbrev(std::move(Abv));
1993 
1994   // Abbreviation for DECL_VAR
1995   Abv = std::make_shared<BitCodeAbbrev>();
1996   Abv->Add(BitCodeAbbrevOp(serialization::DECL_VAR));
1997   // Redeclarable
1998   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
1999   // Decl
2000   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2001   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2002   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2003   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2004   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2005   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2006   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2007   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2008   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2009   Abv->Add(BitCodeAbbrevOp(0));                       // ModulePrivate
2010   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2011   // NamedDecl
2012   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2013   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2014   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2015   // ValueDecl
2016   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2017   // DeclaratorDecl
2018   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
2019   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
2020   // VarDecl
2021   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // SClass
2022   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // TSCSpec
2023   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // InitStyle
2024   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsThisDeclarationADemotedDefinition
2025   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isExceptionVariable
2026   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isNRVOVariable
2027   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCXXForRangeDecl
2028   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isARCPseudoStrong
2029   Abv->Add(BitCodeAbbrevOp(0));                         // isInline
2030   Abv->Add(BitCodeAbbrevOp(0));                         // isInlineSpecified
2031   Abv->Add(BitCodeAbbrevOp(0));                         // isConstexpr
2032   Abv->Add(BitCodeAbbrevOp(0));                         // isInitCapture
2033   Abv->Add(BitCodeAbbrevOp(0));                         // isPrevDeclInSameScope
2034   Abv->Add(BitCodeAbbrevOp(0));                         // ImplicitParamKind
2035   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
2036   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // IsInitICE (local)
2037   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // VarKind (local enum)
2038   // Type Source Info
2039   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2040   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2041   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2042   DeclVarAbbrev = Stream.EmitAbbrev(std::move(Abv));
2043 
2044   // Abbreviation for DECL_CXX_METHOD
2045   Abv = std::make_shared<BitCodeAbbrev>();
2046   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CXX_METHOD));
2047   // RedeclarableDecl
2048   Abv->Add(BitCodeAbbrevOp(0));                         // CanonicalDecl
2049   // Decl
2050   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // DeclContext
2051   Abv->Add(BitCodeAbbrevOp(0));                         // LexicalDeclContext
2052   Abv->Add(BitCodeAbbrevOp(0));                         // Invalid
2053   Abv->Add(BitCodeAbbrevOp(0));                         // HasAttrs
2054   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Implicit
2055   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Used
2056   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Referenced
2057   Abv->Add(BitCodeAbbrevOp(0));                         // InObjCContainer
2058   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // Access
2059   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ModulePrivate
2060   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SubmoduleID
2061   // NamedDecl
2062   Abv->Add(BitCodeAbbrevOp(DeclarationName::Identifier)); // NameKind
2063   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Identifier
2064   Abv->Add(BitCodeAbbrevOp(0));                         // AnonDeclNumber
2065   // ValueDecl
2066   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Type
2067   // DeclaratorDecl
2068   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InnerLocStart
2069   Abv->Add(BitCodeAbbrevOp(0));                         // HasExtInfo
2070   // FunctionDecl
2071   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 11)); // IDNS
2072   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // StorageClass
2073   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Inline
2074   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // InlineSpecified
2075   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ExplicitSpecified
2076   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // VirtualAsWritten
2077   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Pure
2078   Abv->Add(BitCodeAbbrevOp(0));                         // HasInheritedProto
2079   Abv->Add(BitCodeAbbrevOp(1));                         // HasWrittenProto
2080   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Deleted
2081   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Trivial
2082   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // TrivialForCall
2083   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Defaulted
2084   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ExplicitlyDefaulted
2085   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ImplicitReturnZero
2086   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Constexpr
2087   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // UsesSEHTry
2088   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // SkippedBody
2089   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // MultiVersion
2090   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // LateParsed
2091   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
2092   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LocEnd
2093   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32)); // ODRHash
2094   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // TemplateKind
2095   // This Array slurps the rest of the record. Fortunately we want to encode
2096   // (nearly) all the remaining (variable number of) fields in the same way.
2097   //
2098   // This is the function template information if any, then
2099   //         NumParams and Params[] from FunctionDecl, and
2100   //         NumOverriddenMethods, OverriddenMethods[] from CXXMethodDecl.
2101   //
2102   //  Add an AbbrevOp for 'size then elements' and use it here.
2103   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2104   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2105   DeclCXXMethodAbbrev = Stream.EmitAbbrev(std::move(Abv));
2106 
2107   // Abbreviation for EXPR_DECL_REF
2108   Abv = std::make_shared<BitCodeAbbrev>();
2109   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_DECL_REF));
2110   //Stmt
2111   //Expr
2112   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2113   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2114   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2115   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2116   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2117   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2118   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2119   //DeclRefExpr
2120   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HasQualifier
2121   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //GetDeclFound
2122   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ExplicitTemplateArgs
2123   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HadMultipleCandidates
2124   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2125                            1)); // RefersToEnclosingVariableOrCapture
2126   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclRef
2127   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2128   DeclRefExprAbbrev = Stream.EmitAbbrev(std::move(Abv));
2129 
2130   // Abbreviation for EXPR_INTEGER_LITERAL
2131   Abv = std::make_shared<BitCodeAbbrev>();
2132   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_INTEGER_LITERAL));
2133   //Stmt
2134   //Expr
2135   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2136   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2137   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2138   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2139   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2140   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2141   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2142   //Integer Literal
2143   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2144   Abv->Add(BitCodeAbbrevOp(32));                      // Bit Width
2145   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Value
2146   IntegerLiteralAbbrev = Stream.EmitAbbrev(std::move(Abv));
2147 
2148   // Abbreviation for EXPR_CHARACTER_LITERAL
2149   Abv = std::make_shared<BitCodeAbbrev>();
2150   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_CHARACTER_LITERAL));
2151   //Stmt
2152   //Expr
2153   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2154   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2155   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2156   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2157   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2158   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2159   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2160   //Character Literal
2161   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getValue
2162   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2163   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // getKind
2164   CharacterLiteralAbbrev = Stream.EmitAbbrev(std::move(Abv));
2165 
2166   // Abbreviation for EXPR_IMPLICIT_CAST
2167   Abv = std::make_shared<BitCodeAbbrev>();
2168   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_IMPLICIT_CAST));
2169   // Stmt
2170   // Expr
2171   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2172   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //TypeDependent
2173   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
2174   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
2175   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
2176   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2177   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2178   // CastExpr
2179   Abv->Add(BitCodeAbbrevOp(0)); // PathSize
2180   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 6)); // CastKind
2181   // ImplicitCastExpr
2182   ExprImplicitCastAbbrev = Stream.EmitAbbrev(std::move(Abv));
2183 
2184   Abv = std::make_shared<BitCodeAbbrev>();
2185   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_LEXICAL));
2186   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2187   DeclContextLexicalAbbrev = Stream.EmitAbbrev(std::move(Abv));
2188 
2189   Abv = std::make_shared<BitCodeAbbrev>();
2190   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_VISIBLE));
2191   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2192   DeclContextVisibleLookupAbbrev = Stream.EmitAbbrev(std::move(Abv));
2193 }
2194 
2195 /// isRequiredDecl - Check if this is a "required" Decl, which must be seen by
2196 /// consumers of the AST.
2197 ///
2198 /// Such decls will always be deserialized from the AST file, so we would like
2199 /// this to be as restrictive as possible. Currently the predicate is driven by
2200 /// code generation requirements, if other clients have a different notion of
2201 /// what is "required" then we may have to consider an alternate scheme where
2202 /// clients can iterate over the top-level decls and get information on them,
2203 /// without necessary deserializing them. We could explicitly require such
2204 /// clients to use a separate API call to "realize" the decl. This should be
2205 /// relatively painless since they would presumably only do it for top-level
2206 /// decls.
2207 static bool isRequiredDecl(const Decl *D, ASTContext &Context,
2208                            bool WritingModule) {
2209   // An ObjCMethodDecl is never considered as "required" because its
2210   // implementation container always is.
2211 
2212   // File scoped assembly or obj-c or OMP declare target implementation must be
2213   // seen.
2214   if (isa<FileScopeAsmDecl>(D) || isa<ObjCImplDecl>(D) ||
2215       D->hasAttr<OMPDeclareTargetDeclAttr>())
2216     return true;
2217 
2218   if (WritingModule && (isa<VarDecl>(D) || isa<ImportDecl>(D))) {
2219     // These declarations are part of the module initializer, and are emitted
2220     // if and when the module is imported, rather than being emitted eagerly.
2221     return false;
2222   }
2223 
2224   return Context.DeclMustBeEmitted(D);
2225 }
2226 
2227 void ASTWriter::WriteDecl(ASTContext &Context, Decl *D) {
2228   // Determine the ID for this declaration.
2229   serialization::DeclID ID;
2230   assert(!D->isFromASTFile() && "should not be emitting imported decl");
2231   serialization::DeclID &IDR = DeclIDs[D];
2232   if (IDR == 0)
2233     IDR = NextDeclID++;
2234 
2235   ID = IDR;
2236 
2237   assert(ID >= FirstDeclID && "invalid decl ID");
2238 
2239   RecordData Record;
2240   ASTDeclWriter W(*this, Context, Record);
2241 
2242   // Build a record for this declaration
2243   W.Visit(D);
2244 
2245   // Emit this declaration to the bitstream.
2246   uint64_t Offset = W.Emit(D);
2247 
2248   // Record the offset for this declaration
2249   SourceLocation Loc = D->getLocation();
2250   unsigned Index = ID - FirstDeclID;
2251   if (DeclOffsets.size() == Index)
2252     DeclOffsets.push_back(DeclOffset(Loc, Offset));
2253   else if (DeclOffsets.size() < Index) {
2254     // FIXME: Can/should this happen?
2255     DeclOffsets.resize(Index+1);
2256     DeclOffsets[Index].setLocation(Loc);
2257     DeclOffsets[Index].BitOffset = Offset;
2258   } else {
2259     llvm_unreachable("declarations should be emitted in ID order");
2260   }
2261 
2262   SourceManager &SM = Context.getSourceManager();
2263   if (Loc.isValid() && SM.isLocalSourceLocation(Loc))
2264     associateDeclWithFile(D, ID);
2265 
2266   // Note declarations that should be deserialized eagerly so that we can add
2267   // them to a record in the AST file later.
2268   if (isRequiredDecl(D, Context, WritingModule))
2269     EagerlyDeserializedDecls.push_back(ID);
2270 }
2271 
2272 void ASTRecordWriter::AddFunctionDefinition(const FunctionDecl *FD) {
2273   // Switch case IDs are per function body.
2274   Writer->ClearSwitchCaseIDs();
2275 
2276   assert(FD->doesThisDeclarationHaveABody());
2277   bool ModulesCodegen = false;
2278   if (Writer->WritingModule && !FD->isDependentContext()) {
2279     Optional<GVALinkage> Linkage;
2280     if (Writer->WritingModule->Kind == Module::ModuleInterfaceUnit) {
2281       // When building a C++ Modules TS module interface unit, a strong
2282       // definition in the module interface is provided by the compilation of
2283       // that module interface unit, not by its users. (Inline functions are
2284       // still emitted in module users.)
2285       Linkage = Writer->Context->GetGVALinkageForFunction(FD);
2286       ModulesCodegen = *Linkage == GVA_StrongExternal;
2287     }
2288     if (Writer->Context->getLangOpts().ModulesCodegen) {
2289       // Under -fmodules-codegen, codegen is performed for all non-internal,
2290       // non-always_inline functions.
2291       if (!FD->hasAttr<AlwaysInlineAttr>()) {
2292         if (!Linkage)
2293           Linkage = Writer->Context->GetGVALinkageForFunction(FD);
2294         ModulesCodegen = *Linkage != GVA_Internal;
2295       }
2296     }
2297   }
2298   Record->push_back(ModulesCodegen);
2299   if (ModulesCodegen)
2300     Writer->ModularCodegenDecls.push_back(Writer->GetDeclRef(FD));
2301   if (auto *CD = dyn_cast<CXXConstructorDecl>(FD)) {
2302     Record->push_back(CD->getNumCtorInitializers());
2303     if (CD->getNumCtorInitializers())
2304       AddCXXCtorInitializers(
2305           llvm::makeArrayRef(CD->init_begin(), CD->init_end()));
2306   }
2307   AddStmt(FD->getBody());
2308 }
2309