clang/lib/Serialization/ASTWriterDecl.cpp

   1 //===--- ASTWriterDecl.cpp - Declaration Serialization --------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 //  This file implements serialization for Declarations.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "ASTCommon.h"
  14 #include "clang/AST/Attr.h"
  15 #include "clang/AST/DeclCXX.h"
  16 #include "clang/AST/DeclTemplate.h"
  17 #include "clang/AST/DeclVisitor.h"
  18 #include "clang/AST/Expr.h"
  19 #include "clang/AST/OpenMPClause.h"
  20 #include "clang/AST/PrettyDeclStackTrace.h"
  21 #include "clang/Basic/SourceManager.h"
  22 #include "clang/Serialization/ASTReader.h"
  23 #include "clang/Serialization/ASTRecordWriter.h"
  24 #include "llvm/Bitstream/BitstreamWriter.h"
  25 #include "llvm/Support/ErrorHandling.h"
  26 #include <optional>
  27 using namespace clang;
  28 using namespace serialization;
  29
  30 //===----------------------------------------------------------------------===//
  31 // Declaration serialization
  32 //===----------------------------------------------------------------------===//
  33
  34 namespace clang {
  35   class ASTDeclWriter : public DeclVisitor<ASTDeclWriter, void> {
  36     ASTWriter &Writer;
  37     ASTContext &Context;
  38     ASTRecordWriter Record;
  39
  40     serialization::DeclCode Code;
  41     unsigned AbbrevToUse;
  42
  43   public:
  44     ASTDeclWriter(ASTWriter &Writer, ASTContext &Context,
  45                   ASTWriter::RecordDataImpl &Record)
  46         : Writer(Writer), Context(Context), Record(Writer, Record),
  47           Code((serialization::DeclCode)0), AbbrevToUse(0) {}
  48
  49     uint64_t Emit(Decl *D) {
  50       if (!Code)
  51         llvm::report_fatal_error(StringRef("unexpected declaration kind '") +
  52             D->getDeclKindName() + "'");
  53       return Record.Emit(Code, AbbrevToUse);
  54     }
  55
  56     void Visit(Decl *D);
  57
  58     void VisitDecl(Decl *D);
  59     void VisitPragmaCommentDecl(PragmaCommentDecl *D);
  60     void VisitPragmaDetectMismatchDecl(PragmaDetectMismatchDecl *D);
  61     void VisitTranslationUnitDecl(TranslationUnitDecl *D);
  62     void VisitNamedDecl(NamedDecl *D);
  63     void VisitLabelDecl(LabelDecl *LD);
  64     void VisitNamespaceDecl(NamespaceDecl *D);
  65     void VisitUsingDirectiveDecl(UsingDirectiveDecl *D);
  66     void VisitNamespaceAliasDecl(NamespaceAliasDecl *D);
  67     void VisitTypeDecl(TypeDecl *D);
  68     void VisitTypedefNameDecl(TypedefNameDecl *D);
  69     void VisitTypedefDecl(TypedefDecl *D);
  70     void VisitTypeAliasDecl(TypeAliasDecl *D);
  71     void VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D);
  72     void VisitUnresolvedUsingIfExistsDecl(UnresolvedUsingIfExistsDecl *D);
  73     void VisitTagDecl(TagDecl *D);
  74     void VisitEnumDecl(EnumDecl *D);
  75     void VisitRecordDecl(RecordDecl *D);
  76     void VisitCXXRecordDecl(CXXRecordDecl *D);
  77     void VisitClassTemplateSpecializationDecl(
  78                                             ClassTemplateSpecializationDecl *D);
  79     void VisitClassTemplatePartialSpecializationDecl(
  80                                      ClassTemplatePartialSpecializationDecl *D);
  81     void VisitVarTemplateSpecializationDecl(VarTemplateSpecializationDecl *D);
  82     void VisitVarTemplatePartialSpecializationDecl(
  83         VarTemplatePartialSpecializationDecl *D);
  84     void VisitClassScopeFunctionSpecializationDecl(
  85                                        ClassScopeFunctionSpecializationDecl *D);
  86     void VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
  87     void VisitValueDecl(ValueDecl *D);
  88     void VisitEnumConstantDecl(EnumConstantDecl *D);
  89     void VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D);
  90     void VisitDeclaratorDecl(DeclaratorDecl *D);
  91     void VisitFunctionDecl(FunctionDecl *D);
  92     void VisitCXXDeductionGuideDecl(CXXDeductionGuideDecl *D);
  93     void VisitCXXMethodDecl(CXXMethodDecl *D);
  94     void VisitCXXConstructorDecl(CXXConstructorDecl *D);
  95     void VisitCXXDestructorDecl(CXXDestructorDecl *D);
  96     void VisitCXXConversionDecl(CXXConversionDecl *D);
  97     void VisitFieldDecl(FieldDecl *D);
  98     void VisitMSPropertyDecl(MSPropertyDecl *D);
  99     void VisitMSGuidDecl(MSGuidDecl *D);
 100     void VisitUnnamedGlobalConstantDecl(UnnamedGlobalConstantDecl *D);
 101     void VisitTemplateParamObjectDecl(TemplateParamObjectDecl *D);
 102     void VisitIndirectFieldDecl(IndirectFieldDecl *D);
 103     void VisitVarDecl(VarDecl *D);
 104     void VisitImplicitParamDecl(ImplicitParamDecl *D);
 105     void VisitParmVarDecl(ParmVarDecl *D);
 106     void VisitDecompositionDecl(DecompositionDecl *D);
 107     void VisitBindingDecl(BindingDecl *D);
 108     void VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
 109     void VisitTemplateDecl(TemplateDecl *D);
 110     void VisitConceptDecl(ConceptDecl *D);
 111     void VisitImplicitConceptSpecializationDecl(
 112         ImplicitConceptSpecializationDecl *D);
 113     void VisitRequiresExprBodyDecl(RequiresExprBodyDecl *D);
 114     void VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D);
 115     void VisitClassTemplateDecl(ClassTemplateDecl *D);
 116     void VisitVarTemplateDecl(VarTemplateDecl *D);
 117     void VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
 118     void VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
 119     void VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D);
 120     void VisitUsingDecl(UsingDecl *D);
 121     void VisitUsingEnumDecl(UsingEnumDecl *D);
 122     void VisitUsingPackDecl(UsingPackDecl *D);
 123     void VisitUsingShadowDecl(UsingShadowDecl *D);
 124     void VisitConstructorUsingShadowDecl(ConstructorUsingShadowDecl *D);
 125     void VisitLinkageSpecDecl(LinkageSpecDecl *D);
 126     void VisitExportDecl(ExportDecl *D);
 127     void VisitFileScopeAsmDecl(FileScopeAsmDecl *D);
 128     void VisitTopLevelStmtDecl(TopLevelStmtDecl *D);
 129     void VisitImportDecl(ImportDecl *D);
 130     void VisitAccessSpecDecl(AccessSpecDecl *D);
 131     void VisitFriendDecl(FriendDecl *D);
 132     void VisitFriendTemplateDecl(FriendTemplateDecl *D);
 133     void VisitStaticAssertDecl(StaticAssertDecl *D);
 134     void VisitBlockDecl(BlockDecl *D);
 135     void VisitCapturedDecl(CapturedDecl *D);
 136     void VisitEmptyDecl(EmptyDecl *D);
 137     void VisitLifetimeExtendedTemporaryDecl(LifetimeExtendedTemporaryDecl *D);
 138     void VisitDeclContext(DeclContext *DC);
 139     template <typename T> void VisitRedeclarable(Redeclarable<T> *D);
 140     void VisitHLSLBufferDecl(HLSLBufferDecl *D);
 141
 142     // FIXME: Put in the same order is DeclNodes.td?
 143     void VisitObjCMethodDecl(ObjCMethodDecl *D);
 144     void VisitObjCTypeParamDecl(ObjCTypeParamDecl *D);
 145     void VisitObjCContainerDecl(ObjCContainerDecl *D);
 146     void VisitObjCInterfaceDecl(ObjCInterfaceDecl *D);
 147     void VisitObjCIvarDecl(ObjCIvarDecl *D);
 148     void VisitObjCProtocolDecl(ObjCProtocolDecl *D);
 149     void VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D);
 150     void VisitObjCCategoryDecl(ObjCCategoryDecl *D);
 151     void VisitObjCImplDecl(ObjCImplDecl *D);
 152     void VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D);
 153     void VisitObjCImplementationDecl(ObjCImplementationDecl *D);
 154     void VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D);
 155     void VisitObjCPropertyDecl(ObjCPropertyDecl *D);
 156     void VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D);
 157     void VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D);
 158     void VisitOMPAllocateDecl(OMPAllocateDecl *D);
 159     void VisitOMPRequiresDecl(OMPRequiresDecl *D);
 160     void VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D);
 161     void VisitOMPDeclareMapperDecl(OMPDeclareMapperDecl *D);
 162     void VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D);
 163
 164     /// Add an Objective-C type parameter list to the given record.
 165     void AddObjCTypeParamList(ObjCTypeParamList *typeParams) {
 166       // Empty type parameter list.
 167       if (!typeParams) {
 168         Record.push_back(0);
 169         return;
 170       }
 171
 172       Record.push_back(typeParams->size());
 173       for (auto *typeParam : *typeParams) {
 174         Record.AddDeclRef(typeParam);
 175       }
 176       Record.AddSourceLocation(typeParams->getLAngleLoc());
 177       Record.AddSourceLocation(typeParams->getRAngleLoc());
 178     }
 179
 180     /// Add to the record the first declaration from each module file that
 181     /// provides a declaration of D. The intent is to provide a sufficient
 182     /// set such that reloading this set will load all current redeclarations.
 183     void AddFirstDeclFromEachModule(const Decl *D, bool IncludeLocal) {
 184       llvm::MapVector<ModuleFile*, const Decl*> Firsts;
 185       // FIXME: We can skip entries that we know are implied by others.
 186       for (const Decl *R = D->getMostRecentDecl(); R; R = R->getPreviousDecl()) {
 187         if (R->isFromASTFile())
 188           Firsts[Writer.Chain->getOwningModuleFile(R)] = R;
 189         else if (IncludeLocal)
 190           Firsts[nullptr] = R;
 191       }
 192       for (const auto &F : Firsts)
 193         Record.AddDeclRef(F.second);
 194     }
 195
 196     /// Get the specialization decl from an entry in the specialization list.
 197     template <typename EntryType>
 198     typename RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::DeclType *
 199     getSpecializationDecl(EntryType &T) {
 200       return RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::getDecl(&T);
 201     }
 202
 203     /// Get the list of partial specializations from a template's common ptr.
 204     template<typename T>
 205     decltype(T::PartialSpecializations) &getPartialSpecializations(T *Common) {
 206       return Common->PartialSpecializations;
 207     }
 208     ArrayRef<Decl> getPartialSpecializations(FunctionTemplateDecl::Common *) {
 209       return std::nullopt;
 210     }
 211
 212     template<typename DeclTy>
 213     void AddTemplateSpecializations(DeclTy *D) {
 214       auto *Common = D->getCommonPtr();
 215
 216       // If we have any lazy specializations, and the external AST source is
 217       // our chained AST reader, we can just write out the DeclIDs. Otherwise,
 218       // we need to resolve them to actual declarations.
 219       if (Writer.Chain != Writer.Context->getExternalSource() &&
 220           Common->LazySpecializations) {
 221         D->LoadLazySpecializations();
 222         assert(!Common->LazySpecializations);
 223       }
 224
 225       ArrayRef<DeclID> LazySpecializations;
 226       if (auto *LS = Common->LazySpecializations)
 227         LazySpecializations = llvm::ArrayRef(LS + 1, LS[0]);
 228
 229       // Add a slot to the record for the number of specializations.
 230       unsigned I = Record.size();
 231       Record.push_back(0);
 232
 233       // AddFirstDeclFromEachModule might trigger deserialization, invalidating
 234       // *Specializations iterators.
 235       llvm::SmallVector<const Decl*, 16> Specs;
 236       for (auto &Entry : Common->Specializations)
 237         Specs.push_back(getSpecializationDecl(Entry));
 238       for (auto &Entry : getPartialSpecializations(Common))
 239         Specs.push_back(getSpecializationDecl(Entry));
 240
 241       for (auto *D : Specs) {
 242         assert(D->isCanonicalDecl() && "non-canonical decl in set");
 243         AddFirstDeclFromEachModule(D, /*IncludeLocal*/true);
 244       }
 245       Record.append(LazySpecializations.begin(), LazySpecializations.end());
 246
 247       // Update the size entry we added earlier.
 248       Record[I] = Record.size() - I - 1;
 249     }
 250
 251     /// Ensure that this template specialization is associated with the specified
 252     /// template on reload.
 253     void RegisterTemplateSpecialization(const Decl *Template,
 254                                         const Decl *Specialization) {
 255       Template = Template->getCanonicalDecl();
 256
 257       // If the canonical template is local, we'll write out this specialization
 258       // when we emit it.
 259       // FIXME: We can do the same thing if there is any local declaration of
 260       // the template, to avoid emitting an update record.
 261       if (!Template->isFromASTFile())
 262         return;
 263
 264       // We only need to associate the first local declaration of the
 265       // specialization. The other declarations will get pulled in by it.
 266       if (Writer.getFirstLocalDecl(Specialization) != Specialization)
 267         return;
 268
 269       Writer.DeclUpdates[Template].push_back(ASTWriter::DeclUpdate(
 270           UPD_CXX_ADDED_TEMPLATE_SPECIALIZATION, Specialization));
 271     }
 272   };
 273 }
 274
 275 void ASTDeclWriter::Visit(Decl *D) {
 276   DeclVisitor<ASTDeclWriter>::Visit(D);
 277
 278   // Source locations require array (variable-length) abbreviations.  The
 279   // abbreviation infrastructure requires that arrays are encoded last, so
 280   // we handle it here in the case of those classes derived from DeclaratorDecl
 281   if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D)) {
 282     if (auto *TInfo = DD->getTypeSourceInfo())
 283       Record.AddTypeLoc(TInfo->getTypeLoc());
 284   }
 285
 286   // Handle FunctionDecl's body here and write it after all other Stmts/Exprs
 287   // have been written. We want it last because we will not read it back when
 288   // retrieving it from the AST, we'll just lazily set the offset.
 289   if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
 290     Record.push_back(FD->doesThisDeclarationHaveABody());
 291     if (FD->doesThisDeclarationHaveABody())
 292       Record.AddFunctionDefinition(FD);
 293   }
 294
 295   // If this declaration is also a DeclContext, write blocks for the
 296   // declarations that lexically stored inside its context and those
 297   // declarations that are visible from its context.
 298   if (DeclContext *DC = dyn_cast<DeclContext>(D))
 299     VisitDeclContext(DC);
 300 }
 301
 302 void ASTDeclWriter::VisitDecl(Decl *D) {
 303   Record.AddDeclRef(cast_or_null<Decl>(D->getDeclContext()));
 304   if (D->getDeclContext() != D->getLexicalDeclContext())
 305     Record.AddDeclRef(cast_or_null<Decl>(D->getLexicalDeclContext()));
 306   else
 307     Record.push_back(0);
 308   Record.push_back(D->isInvalidDecl());
 309   Record.push_back(D->hasAttrs());
 310   if (D->hasAttrs())
 311     Record.AddAttributes(D->getAttrs());
 312   Record.push_back(D->isImplicit());
 313   Record.push_back(D->isUsed(false));
 314   Record.push_back(D->isReferenced());
 315   Record.push_back(D->isTopLevelDeclInObjCContainer());
 316   Record.push_back(D->getAccess());
 317   Record.push_back((uint64_t)D->getModuleOwnershipKind());
 318   Record.push_back(Writer.getSubmoduleID(D->getOwningModule()));
 319
 320   // If this declaration injected a name into a context different from its
 321   // lexical context, and that context is an imported namespace, we need to
 322   // update its visible declarations to include this name.
 323   //
 324   // This happens when we instantiate a class with a friend declaration or a
 325   // function with a local extern declaration, for instance.
 326   //
 327   // FIXME: Can we handle this in AddedVisibleDecl instead?
 328   if (D->isOutOfLine()) {
 329     auto *DC = D->getDeclContext();
 330     while (auto *NS = dyn_cast<NamespaceDecl>(DC->getRedeclContext())) {
 331       if (!NS->isFromASTFile())
 332         break;
 333       Writer.UpdatedDeclContexts.insert(NS->getPrimaryContext());
 334       if (!NS->isInlineNamespace())
 335         break;
 336       DC = NS->getParent();
 337     }
 338   }
 339 }
 340
 341 void ASTDeclWriter::VisitPragmaCommentDecl(PragmaCommentDecl *D) {
 342   StringRef Arg = D->getArg();
 343   Record.push_back(Arg.size());
 344   VisitDecl(D);
 345   Record.AddSourceLocation(D->getBeginLoc());
 346   Record.push_back(D->getCommentKind());
 347   Record.AddString(Arg);
 348   Code = serialization::DECL_PRAGMA_COMMENT;
 349 }
 350
 351 void ASTDeclWriter::VisitPragmaDetectMismatchDecl(
 352     PragmaDetectMismatchDecl *D) {
 353   StringRef Name = D->getName();
 354   StringRef Value = D->getValue();
 355   Record.push_back(Name.size() + 1 + Value.size());
 356   VisitDecl(D);
 357   Record.AddSourceLocation(D->getBeginLoc());
 358   Record.AddString(Name);
 359   Record.AddString(Value);
 360   Code = serialization::DECL_PRAGMA_DETECT_MISMATCH;
 361 }
 362
 363 void ASTDeclWriter::VisitTranslationUnitDecl(TranslationUnitDecl *D) {
 364   llvm_unreachable("Translation units aren't directly serialized");
 365 }
 366
 367 void ASTDeclWriter::VisitNamedDecl(NamedDecl *D) {
 368   VisitDecl(D);
 369   Record.AddDeclarationName(D->getDeclName());
 370   Record.push_back(needsAnonymousDeclarationNumber(D)
 371                        ? Writer.getAnonymousDeclarationNumber(D)
 372                        : 0);
 373 }
 374
 375 void ASTDeclWriter::VisitTypeDecl(TypeDecl *D) {
 376   VisitNamedDecl(D);
 377   Record.AddSourceLocation(D->getBeginLoc());
 378   Record.AddTypeRef(QualType(D->getTypeForDecl(), 0));
 379 }
 380
 381 void ASTDeclWriter::VisitTypedefNameDecl(TypedefNameDecl *D) {
 382   VisitRedeclarable(D);
 383   VisitTypeDecl(D);
 384   Record.AddTypeSourceInfo(D->getTypeSourceInfo());
 385   Record.push_back(D->isModed());
 386   if (D->isModed())
 387     Record.AddTypeRef(D->getUnderlyingType());
 388   Record.AddDeclRef(D->getAnonDeclWithTypedefName(false));
 389 }
 390
 391 void ASTDeclWriter::VisitTypedefDecl(TypedefDecl *D) {
 392   VisitTypedefNameDecl(D);
 393   if (D->getDeclContext() == D->getLexicalDeclContext() &&
 394       !D->hasAttrs() &&
 395       !D->isImplicit() &&
 396       D->getFirstDecl() == D->getMostRecentDecl() &&
 397       !D->isInvalidDecl() &&
 398       !D->isTopLevelDeclInObjCContainer() &&
 399       !D->isModulePrivate() &&
 400       !needsAnonymousDeclarationNumber(D) &&
 401       D->getDeclName().getNameKind() == DeclarationName::Identifier)
 402     AbbrevToUse = Writer.getDeclTypedefAbbrev();
 403
 404   Code = serialization::DECL_TYPEDEF;
 405 }
 406
 407 void ASTDeclWriter::VisitTypeAliasDecl(TypeAliasDecl *D) {
 408   VisitTypedefNameDecl(D);
 409   Record.AddDeclRef(D->getDescribedAliasTemplate());
 410   Code = serialization::DECL_TYPEALIAS;
 411 }
 412
 413 void ASTDeclWriter::VisitTagDecl(TagDecl *D) {
 414   static_assert(DeclContext::NumTagDeclBits == 10,
 415                 "You need to update the serializer after you change the "
 416                 "TagDeclBits");
 417
 418   VisitRedeclarable(D);
 419   VisitTypeDecl(D);
 420   Record.push_back(D->getIdentifierNamespace());
 421   Record.push_back((unsigned)D->getTagKind()); // FIXME: stable encoding
 422   if (!isa<CXXRecordDecl>(D))
 423     Record.push_back(D->isCompleteDefinition());
 424   Record.push_back(D->isEmbeddedInDeclarator());
 425   Record.push_back(D->isFreeStanding());
 426   Record.push_back(D->isCompleteDefinitionRequired());
 427   Record.AddSourceRange(D->getBraceRange());
 428
 429   if (D->hasExtInfo()) {
 430     Record.push_back(1);
 431     Record.AddQualifierInfo(*D->getExtInfo());
 432   } else if (auto *TD = D->getTypedefNameForAnonDecl()) {
 433     Record.push_back(2);
 434     Record.AddDeclRef(TD);
 435     Record.AddIdentifierRef(TD->getDeclName().getAsIdentifierInfo());
 436   } else {
 437     Record.push_back(0);
 438   }
 439 }
 440
 441 void ASTDeclWriter::VisitEnumDecl(EnumDecl *D) {
 442   static_assert(DeclContext::NumEnumDeclBits == 20,
 443                 "You need to update the serializer after you change the "
 444                 "EnumDeclBits");
 445
 446   VisitTagDecl(D);
 447   Record.AddTypeSourceInfo(D->getIntegerTypeSourceInfo());
 448   if (!D->getIntegerTypeSourceInfo())
 449     Record.AddTypeRef(D->getIntegerType());
 450   Record.AddTypeRef(D->getPromotionType());
 451   Record.push_back(D->getNumPositiveBits());
 452   Record.push_back(D->getNumNegativeBits());
 453   Record.push_back(D->isScoped());
 454   Record.push_back(D->isScopedUsingClassTag());
 455   Record.push_back(D->isFixed());
 456   Record.push_back(D->getODRHash());
 457
 458   if (MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo()) {
 459     Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
 460     Record.push_back(MemberInfo->getTemplateSpecializationKind());
 461     Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
 462   } else {
 463     Record.AddDeclRef(nullptr);
 464   }
 465
 466   if (D->getDeclContext() == D->getLexicalDeclContext() &&
 467       !D->hasAttrs() &&
 468       !D->isImplicit() &&
 469       !D->isUsed(false) &&
 470       !D->hasExtInfo() &&
 471       !D->getTypedefNameForAnonDecl() &&
 472       D->getFirstDecl() == D->getMostRecentDecl() &&
 473       !D->isInvalidDecl() &&
 474       !D->isReferenced() &&
 475       !D->isTopLevelDeclInObjCContainer() &&
 476       D->getAccess() == AS_none &&
 477       !D->isModulePrivate() &&
 478       !CXXRecordDecl::classofKind(D->getKind()) &&
 479       !D->getIntegerTypeSourceInfo() &&
 480       !D->getMemberSpecializationInfo() &&
 481       !needsAnonymousDeclarationNumber(D) &&
 482       D->getDeclName().getNameKind() == DeclarationName::Identifier)
 483     AbbrevToUse = Writer.getDeclEnumAbbrev();
 484
 485   Code = serialization::DECL_ENUM;
 486 }
 487
 488 void ASTDeclWriter::VisitRecordDecl(RecordDecl *D) {
 489   static_assert(DeclContext::NumRecordDeclBits == 41,
 490                 "You need to update the serializer after you change the "
 491                 "RecordDeclBits");
 492
 493   VisitTagDecl(D);
 494   Record.push_back(D->hasFlexibleArrayMember());
 495   Record.push_back(D->isAnonymousStructOrUnion());
 496   Record.push_back(D->hasObjectMember());
 497   Record.push_back(D->hasVolatileMember());
 498   Record.push_back(D->isNonTrivialToPrimitiveDefaultInitialize());
 499   Record.push_back(D->isNonTrivialToPrimitiveCopy());
 500   Record.push_back(D->isNonTrivialToPrimitiveDestroy());
 501   Record.push_back(D->hasNonTrivialToPrimitiveDefaultInitializeCUnion());
 502   Record.push_back(D->hasNonTrivialToPrimitiveDestructCUnion());
 503   Record.push_back(D->hasNonTrivialToPrimitiveCopyCUnion());
 504   Record.push_back(D->isParamDestroyedInCallee());
 505   Record.push_back(D->getArgPassingRestrictions());
 506   // Only compute this for C/Objective-C, in C++ this is computed as part
 507   // of CXXRecordDecl.
 508   if (!isa<CXXRecordDecl>(D))
 509     Record.push_back(D->getODRHash());
 510
 511   if (D->getDeclContext() == D->getLexicalDeclContext() &&
 512       !D->hasAttrs() &&
 513       !D->isImplicit() &&
 514       !D->isUsed(false) &&
 515       !D->hasExtInfo() &&
 516       !D->getTypedefNameForAnonDecl() &&
 517       D->getFirstDecl() == D->getMostRecentDecl() &&
 518       !D->isInvalidDecl() &&
 519       !D->isReferenced() &&
 520       !D->isTopLevelDeclInObjCContainer() &&
 521       D->getAccess() == AS_none &&
 522       !D->isModulePrivate() &&
 523       !CXXRecordDecl::classofKind(D->getKind()) &&
 524       !needsAnonymousDeclarationNumber(D) &&
 525       D->getDeclName().getNameKind() == DeclarationName::Identifier)
 526     AbbrevToUse = Writer.getDeclRecordAbbrev();
 527
 528   Code = serialization::DECL_RECORD;
 529 }
 530
 531 void ASTDeclWriter::VisitValueDecl(ValueDecl *D) {
 532   VisitNamedDecl(D);
 533   Record.AddTypeRef(D->getType());
 534 }
 535
 536 void ASTDeclWriter::VisitEnumConstantDecl(EnumConstantDecl *D) {
 537   VisitValueDecl(D);
 538   Record.push_back(D->getInitExpr()? 1 : 0);
 539   if (D->getInitExpr())
 540     Record.AddStmt(D->getInitExpr());
 541   Record.AddAPSInt(D->getInitVal());
 542
 543   Code = serialization::DECL_ENUM_CONSTANT;
 544 }
 545
 546 void ASTDeclWriter::VisitDeclaratorDecl(DeclaratorDecl *D) {
 547   VisitValueDecl(D);
 548   Record.AddSourceLocation(D->getInnerLocStart());
 549   Record.push_back(D->hasExtInfo());
 550   if (D->hasExtInfo()) {
 551     DeclaratorDecl::ExtInfo *Info = D->getExtInfo();
 552     Record.AddQualifierInfo(*Info);
 553     Record.AddStmt(Info->TrailingRequiresClause);
 554   }
 555   // The location information is deferred until the end of the record.
 556   Record.AddTypeRef(D->getTypeSourceInfo() ? D->getTypeSourceInfo()->getType()
 557                                            : QualType());
 558 }
 559
 560 void ASTDeclWriter::VisitFunctionDecl(FunctionDecl *D) {
 561   static_assert(DeclContext::NumFunctionDeclBits == 29,
 562                 "You need to update the serializer after you change the "
 563                 "FunctionDeclBits");
 564
 565   VisitRedeclarable(D);
 566
 567   Record.push_back(D->getTemplatedKind());
 568   switch (D->getTemplatedKind()) {
 569   case FunctionDecl::TK_NonTemplate:
 570     break;
 571   case FunctionDecl::TK_DependentNonTemplate:
 572     Record.AddDeclRef(D->getInstantiatedFromDecl());
 573     break;
 574   case FunctionDecl::TK_FunctionTemplate:
 575     Record.AddDeclRef(D->getDescribedFunctionTemplate());
 576     break;
 577   case FunctionDecl::TK_MemberSpecialization: {
 578     MemberSpecializationInfo *MemberInfo = D->getMemberSpecializationInfo();
 579     Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
 580     Record.push_back(MemberInfo->getTemplateSpecializationKind());
 581     Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
 582     break;
 583   }
 584   case FunctionDecl::TK_FunctionTemplateSpecialization: {
 585     FunctionTemplateSpecializationInfo *
 586       FTSInfo = D->getTemplateSpecializationInfo();
 587
 588     RegisterTemplateSpecialization(FTSInfo->getTemplate(), D);
 589
 590     Record.AddDeclRef(FTSInfo->getTemplate());
 591     Record.push_back(FTSInfo->getTemplateSpecializationKind());
 592
 593     // Template arguments.
 594     Record.AddTemplateArgumentList(FTSInfo->TemplateArguments);
 595
 596     // Template args as written.
 597     Record.push_back(FTSInfo->TemplateArgumentsAsWritten != nullptr);
 598     if (FTSInfo->TemplateArgumentsAsWritten) {
 599       Record.push_back(FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs);
 600       for (int i=0, e = FTSInfo->TemplateArgumentsAsWritten->NumTemplateArgs;
 601              i!=e; ++i)
 602         Record.AddTemplateArgumentLoc(
 603             (*FTSInfo->TemplateArgumentsAsWritten)[i]);
 604       Record.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->LAngleLoc);
 605       Record.AddSourceLocation(FTSInfo->TemplateArgumentsAsWritten->RAngleLoc);
 606     }
 607
 608     Record.AddSourceLocation(FTSInfo->getPointOfInstantiation());
 609
 610     if (MemberSpecializationInfo *MemberInfo =
 611         FTSInfo->getMemberSpecializationInfo()) {
 612       Record.push_back(1);
 613       Record.AddDeclRef(MemberInfo->getInstantiatedFrom());
 614       Record.push_back(MemberInfo->getTemplateSpecializationKind());
 615       Record.AddSourceLocation(MemberInfo->getPointOfInstantiation());
 616     } else {
 617       Record.push_back(0);
 618     }
 619
 620     if (D->isCanonicalDecl()) {
 621       // Write the template that contains the specializations set. We will
 622       // add a FunctionTemplateSpecializationInfo to it when reading.
 623       Record.AddDeclRef(FTSInfo->getTemplate()->getCanonicalDecl());
 624     }
 625     break;
 626   }
 627   case FunctionDecl::TK_DependentFunctionTemplateSpecialization: {
 628     DependentFunctionTemplateSpecializationInfo *
 629       DFTSInfo = D->getDependentSpecializationInfo();
 630
 631     // Templates.
 632     Record.push_back(DFTSInfo->getNumTemplates());
 633     for (int i=0, e = DFTSInfo->getNumTemplates(); i != e; ++i)
 634       Record.AddDeclRef(DFTSInfo->getTemplate(i));
 635
 636     // Templates args.
 637     Record.push_back(DFTSInfo->getNumTemplateArgs());
 638     for (int i=0, e = DFTSInfo->getNumTemplateArgs(); i != e; ++i)
 639       Record.AddTemplateArgumentLoc(DFTSInfo->getTemplateArg(i));
 640     Record.AddSourceLocation(DFTSInfo->getLAngleLoc());
 641     Record.AddSourceLocation(DFTSInfo->getRAngleLoc());
 642     break;
 643   }
 644   }
 645
 646   VisitDeclaratorDecl(D);
 647   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
 648   Record.push_back(D->getIdentifierNamespace());
 649
 650   // FunctionDecl's body is handled last at ASTWriterDecl::Visit,
 651   // after everything else is written.
 652   Record.push_back(
 653       static_cast<int>(D->getStorageClass())); // FIXME: stable encoding
 654   Record.push_back(D->isInlineSpecified());
 655   Record.push_back(D->isInlined());
 656   Record.push_back(D->isVirtualAsWritten());
 657   Record.push_back(D->isPure());
 658   Record.push_back(D->hasInheritedPrototype());
 659   Record.push_back(D->hasWrittenPrototype());
 660   Record.push_back(D->isDeletedBit());
 661   Record.push_back(D->isTrivial());
 662   Record.push_back(D->isTrivialForCall());
 663   Record.push_back(D->isDefaulted());
 664   Record.push_back(D->isExplicitlyDefaulted());
 665   Record.push_back(D->isIneligibleOrNotSelected());
 666   Record.push_back(D->hasImplicitReturnZero());
 667   Record.push_back(static_cast<uint64_t>(D->getConstexprKind()));
 668   Record.push_back(D->usesSEHTry());
 669   Record.push_back(D->hasSkippedBody());
 670   Record.push_back(D->isMultiVersion());
 671   Record.push_back(D->isLateTemplateParsed());
 672   Record.push_back(D->FriendConstraintRefersToEnclosingTemplate());
 673   Record.push_back(D->getLinkageInternal());
 674   Record.AddSourceLocation(D->getEndLoc());
 675   Record.AddSourceLocation(D->getDefaultLoc());
 676
 677   Record.push_back(D->getODRHash());
 678
 679   if (D->isDefaulted()) {
 680     if (auto *FDI = D->getDefaultedFunctionInfo()) {
 681       Record.push_back(FDI->getUnqualifiedLookups().size());
 682       for (DeclAccessPair P : FDI->getUnqualifiedLookups()) {
 683         Record.AddDeclRef(P.getDecl());
 684         Record.push_back(P.getAccess());
 685       }
 686     } else {
 687       Record.push_back(0);
 688     }
 689   }
 690
 691   Record.push_back(D->param_size());
 692   for (auto *P : D->parameters())
 693     Record.AddDeclRef(P);
 694   Code = serialization::DECL_FUNCTION;
 695 }
 696
 697 static void addExplicitSpecifier(ExplicitSpecifier ES,
 698                                  ASTRecordWriter &Record) {
 699   uint64_t Kind = static_cast<uint64_t>(ES.getKind());
 700   Kind = Kind << 1 | static_cast<bool>(ES.getExpr());
 701   Record.push_back(Kind);
 702   if (ES.getExpr()) {
 703     Record.AddStmt(ES.getExpr());
 704   }
 705 }
 706
 707 void ASTDeclWriter::VisitCXXDeductionGuideDecl(CXXDeductionGuideDecl *D) {
 708   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
 709   Record.AddDeclRef(D->Ctor);
 710   VisitFunctionDecl(D);
 711   Record.push_back(D->isCopyDeductionCandidate());
 712   Code = serialization::DECL_CXX_DEDUCTION_GUIDE;
 713 }
 714
 715 void ASTDeclWriter::VisitObjCMethodDecl(ObjCMethodDecl *D) {
 716   static_assert(DeclContext::NumObjCMethodDeclBits == 24,
 717                 "You need to update the serializer after you change the "
 718                 "ObjCMethodDeclBits");
 719
 720   VisitNamedDecl(D);
 721   // FIXME: convert to LazyStmtPtr?
 722   // Unlike C/C++, method bodies will never be in header files.
 723   bool HasBodyStuff = D->getBody() != nullptr;
 724   Record.push_back(HasBodyStuff);
 725   if (HasBodyStuff) {
 726     Record.AddStmt(D->getBody());
 727   }
 728   Record.AddDeclRef(D->getSelfDecl());
 729   Record.AddDeclRef(D->getCmdDecl());
 730   Record.push_back(D->isInstanceMethod());
 731   Record.push_back(D->isVariadic());
 732   Record.push_back(D->isPropertyAccessor());
 733   Record.push_back(D->isSynthesizedAccessorStub());
 734   Record.push_back(D->isDefined());
 735   Record.push_back(D->isOverriding());
 736   Record.push_back(D->hasSkippedBody());
 737
 738   Record.push_back(D->isRedeclaration());
 739   Record.push_back(D->hasRedeclaration());
 740   if (D->hasRedeclaration()) {
 741     assert(Context.getObjCMethodRedeclaration(D));
 742     Record.AddDeclRef(Context.getObjCMethodRedeclaration(D));
 743   }
 744
 745   // FIXME: stable encoding for @required/@optional
 746   Record.push_back(D->getImplementationControl());
 747   // FIXME: stable encoding for in/out/inout/bycopy/byref/oneway/nullability
 748   Record.push_back(D->getObjCDeclQualifier());
 749   Record.push_back(D->hasRelatedResultType());
 750   Record.AddTypeRef(D->getReturnType());
 751   Record.AddTypeSourceInfo(D->getReturnTypeSourceInfo());
 752   Record.AddSourceLocation(D->getEndLoc());
 753   Record.push_back(D->param_size());
 754   for (const auto *P : D->parameters())
 755     Record.AddDeclRef(P);
 756
 757   Record.push_back(D->getSelLocsKind());
 758   unsigned NumStoredSelLocs = D->getNumStoredSelLocs();
 759   SourceLocation *SelLocs = D->getStoredSelLocs();
 760   Record.push_back(NumStoredSelLocs);
 761   for (unsigned i = 0; i != NumStoredSelLocs; ++i)
 762     Record.AddSourceLocation(SelLocs[i]);
 763
 764   Code = serialization::DECL_OBJC_METHOD;
 765 }
 766
 767 void ASTDeclWriter::VisitObjCTypeParamDecl(ObjCTypeParamDecl *D) {
 768   VisitTypedefNameDecl(D);
 769   Record.push_back(D->Variance);
 770   Record.push_back(D->Index);
 771   Record.AddSourceLocation(D->VarianceLoc);
 772   Record.AddSourceLocation(D->ColonLoc);
 773
 774   Code = serialization::DECL_OBJC_TYPE_PARAM;
 775 }
 776
 777 void ASTDeclWriter::VisitObjCContainerDecl(ObjCContainerDecl *D) {
 778   static_assert(DeclContext::NumObjCContainerDeclBits == 51,
 779                 "You need to update the serializer after you change the "
 780                 "ObjCContainerDeclBits");
 781
 782   VisitNamedDecl(D);
 783   Record.AddSourceLocation(D->getAtStartLoc());
 784   Record.AddSourceRange(D->getAtEndRange());
 785   // Abstract class (no need to define a stable serialization::DECL code).
 786 }
 787
 788 void ASTDeclWriter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
 789   VisitRedeclarable(D);
 790   VisitObjCContainerDecl(D);
 791   Record.AddTypeRef(QualType(D->getTypeForDecl(), 0));
 792   AddObjCTypeParamList(D->TypeParamList);
 793
 794   Record.push_back(D->isThisDeclarationADefinition());
 795   if (D->isThisDeclarationADefinition()) {
 796     // Write the DefinitionData
 797     ObjCInterfaceDecl::DefinitionData &Data = D->data();
 798
 799     Record.AddTypeSourceInfo(D->getSuperClassTInfo());
 800     Record.AddSourceLocation(D->getEndOfDefinitionLoc());
 801     Record.push_back(Data.HasDesignatedInitializers);
 802     Record.push_back(D->getODRHash());
 803
 804     // Write out the protocols that are directly referenced by the @interface.
 805     Record.push_back(Data.ReferencedProtocols.size());
 806     for (const auto *P : D->protocols())
 807       Record.AddDeclRef(P);
 808     for (const auto &PL : D->protocol_locs())
 809       Record.AddSourceLocation(PL);
 810
 811     // Write out the protocols that are transitively referenced.
 812     Record.push_back(Data.AllReferencedProtocols.size());
 813     for (ObjCList<ObjCProtocolDecl>::iterator
 814               P = Data.AllReferencedProtocols.begin(),
 815            PEnd = Data.AllReferencedProtocols.end();
 816          P != PEnd; ++P)
 817       Record.AddDeclRef(*P);
 818
 819
 820     if (ObjCCategoryDecl *Cat = D->getCategoryListRaw()) {
 821       // Ensure that we write out the set of categories for this class.
 822       Writer.ObjCClassesWithCategories.insert(D);
 823
 824       // Make sure that the categories get serialized.
 825       for (; Cat; Cat = Cat->getNextClassCategoryRaw())
 826         (void)Writer.GetDeclRef(Cat);
 827     }
 828   }
 829
 830   Code = serialization::DECL_OBJC_INTERFACE;
 831 }
 832
 833 void ASTDeclWriter::VisitObjCIvarDecl(ObjCIvarDecl *D) {
 834   VisitFieldDecl(D);
 835   // FIXME: stable encoding for @public/@private/@protected/@package
 836   Record.push_back(D->getAccessControl());
 837   Record.push_back(D->getSynthesize());
 838
 839   if (D->getDeclContext() == D->getLexicalDeclContext() &&
 840       !D->hasAttrs() &&
 841       !D->isImplicit() &&
 842       !D->isUsed(false) &&
 843       !D->isInvalidDecl() &&
 844       !D->isReferenced() &&
 845       !D->isModulePrivate() &&
 846       !D->getBitWidth() &&
 847       !D->hasExtInfo() &&
 848       D->getDeclName())
 849     AbbrevToUse = Writer.getDeclObjCIvarAbbrev();
 850
 851   Code = serialization::DECL_OBJC_IVAR;
 852 }
 853
 854 void ASTDeclWriter::VisitObjCProtocolDecl(ObjCProtocolDecl *D) {
 855   VisitRedeclarable(D);
 856   VisitObjCContainerDecl(D);
 857
 858   Record.push_back(D->isThisDeclarationADefinition());
 859   if (D->isThisDeclarationADefinition()) {
 860     Record.push_back(D->protocol_size());
 861     for (const auto *I : D->protocols())
 862       Record.AddDeclRef(I);
 863     for (const auto &PL : D->protocol_locs())
 864       Record.AddSourceLocation(PL);
 865     Record.push_back(D->getODRHash());
 866   }
 867
 868   Code = serialization::DECL_OBJC_PROTOCOL;
 869 }
 870
 871 void ASTDeclWriter::VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D) {
 872   VisitFieldDecl(D);
 873   Code = serialization::DECL_OBJC_AT_DEFS_FIELD;
 874 }
 875
 876 void ASTDeclWriter::VisitObjCCategoryDecl(ObjCCategoryDecl *D) {
 877   VisitObjCContainerDecl(D);
 878   Record.AddSourceLocation(D->getCategoryNameLoc());
 879   Record.AddSourceLocation(D->getIvarLBraceLoc());
 880   Record.AddSourceLocation(D->getIvarRBraceLoc());
 881   Record.AddDeclRef(D->getClassInterface());
 882   AddObjCTypeParamList(D->TypeParamList);
 883   Record.push_back(D->protocol_size());
 884   for (const auto *I : D->protocols())
 885     Record.AddDeclRef(I);
 886   for (const auto &PL : D->protocol_locs())
 887     Record.AddSourceLocation(PL);
 888   Code = serialization::DECL_OBJC_CATEGORY;
 889 }
 890
 891 void ASTDeclWriter::VisitObjCCompatibleAliasDecl(ObjCCompatibleAliasDecl *D) {
 892   VisitNamedDecl(D);
 893   Record.AddDeclRef(D->getClassInterface());
 894   Code = serialization::DECL_OBJC_COMPATIBLE_ALIAS;
 895 }
 896
 897 void ASTDeclWriter::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
 898   VisitNamedDecl(D);
 899   Record.AddSourceLocation(D->getAtLoc());
 900   Record.AddSourceLocation(D->getLParenLoc());
 901   Record.AddTypeRef(D->getType());
 902   Record.AddTypeSourceInfo(D->getTypeSourceInfo());
 903   // FIXME: stable encoding
 904   Record.push_back((unsigned)D->getPropertyAttributes());
 905   Record.push_back((unsigned)D->getPropertyAttributesAsWritten());
 906   // FIXME: stable encoding
 907   Record.push_back((unsigned)D->getPropertyImplementation());
 908   Record.AddDeclarationName(D->getGetterName());
 909   Record.AddSourceLocation(D->getGetterNameLoc());
 910   Record.AddDeclarationName(D->getSetterName());
 911   Record.AddSourceLocation(D->getSetterNameLoc());
 912   Record.AddDeclRef(D->getGetterMethodDecl());
 913   Record.AddDeclRef(D->getSetterMethodDecl());
 914   Record.AddDeclRef(D->getPropertyIvarDecl());
 915   Code = serialization::DECL_OBJC_PROPERTY;
 916 }
 917
 918 void ASTDeclWriter::VisitObjCImplDecl(ObjCImplDecl *D) {
 919   VisitObjCContainerDecl(D);
 920   Record.AddDeclRef(D->getClassInterface());
 921   // Abstract class (no need to define a stable serialization::DECL code).
 922 }
 923
 924 void ASTDeclWriter::VisitObjCCategoryImplDecl(ObjCCategoryImplDecl *D) {
 925   VisitObjCImplDecl(D);
 926   Record.AddSourceLocation(D->getCategoryNameLoc());
 927   Code = serialization::DECL_OBJC_CATEGORY_IMPL;
 928 }
 929
 930 void ASTDeclWriter::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
 931   VisitObjCImplDecl(D);
 932   Record.AddDeclRef(D->getSuperClass());
 933   Record.AddSourceLocation(D->getSuperClassLoc());
 934   Record.AddSourceLocation(D->getIvarLBraceLoc());
 935   Record.AddSourceLocation(D->getIvarRBraceLoc());
 936   Record.push_back(D->hasNonZeroConstructors());
 937   Record.push_back(D->hasDestructors());
 938   Record.push_back(D->NumIvarInitializers);
 939   if (D->NumIvarInitializers)
 940     Record.AddCXXCtorInitializers(
 941         llvm::ArrayRef(D->init_begin(), D->init_end()));
 942   Code = serialization::DECL_OBJC_IMPLEMENTATION;
 943 }
 944
 945 void ASTDeclWriter::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
 946   VisitDecl(D);
 947   Record.AddSourceLocation(D->getBeginLoc());
 948   Record.AddDeclRef(D->getPropertyDecl());
 949   Record.AddDeclRef(D->getPropertyIvarDecl());
 950   Record.AddSourceLocation(D->getPropertyIvarDeclLoc());
 951   Record.AddDeclRef(D->getGetterMethodDecl());
 952   Record.AddDeclRef(D->getSetterMethodDecl());
 953   Record.AddStmt(D->getGetterCXXConstructor());
 954   Record.AddStmt(D->getSetterCXXAssignment());
 955   Code = serialization::DECL_OBJC_PROPERTY_IMPL;
 956 }
 957
 958 void ASTDeclWriter::VisitFieldDecl(FieldDecl *D) {
 959   VisitDeclaratorDecl(D);
 960   Record.push_back(D->isMutable());
 961
 962   FieldDecl::InitStorageKind ISK = D->InitStorage.getInt();
 963   Record.push_back(ISK);
 964   if (ISK == FieldDecl::ISK_CapturedVLAType)
 965     Record.AddTypeRef(QualType(D->getCapturedVLAType(), 0));
 966   else if (ISK)
 967     Record.AddStmt(D->getInClassInitializer());
 968
 969   Record.AddStmt(D->getBitWidth());
 970
 971   if (!D->getDeclName())
 972     Record.AddDeclRef(Context.getInstantiatedFromUnnamedFieldDecl(D));
 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->isModulePrivate() &&
 982       !D->getBitWidth() &&
 983       !D->hasInClassInitializer() &&
 984       !D->hasCapturedVLAType() &&
 985       !D->hasExtInfo() &&
 986       !ObjCIvarDecl::classofKind(D->getKind()) &&
 987       !ObjCAtDefsFieldDecl::classofKind(D->getKind()) &&
 988       D->getDeclName())
 989     AbbrevToUse = Writer.getDeclFieldAbbrev();
 990
 991   Code = serialization::DECL_FIELD;
 992 }
 993
 994 void ASTDeclWriter::VisitMSPropertyDecl(MSPropertyDecl *D) {
 995   VisitDeclaratorDecl(D);
 996   Record.AddIdentifierRef(D->getGetterId());
 997   Record.AddIdentifierRef(D->getSetterId());
 998   Code = serialization::DECL_MS_PROPERTY;
 999 }
1000
1001 void ASTDeclWriter::VisitMSGuidDecl(MSGuidDecl *D) {
1002   VisitValueDecl(D);
1003   MSGuidDecl::Parts Parts = D->getParts();
1004   Record.push_back(Parts.Part1);
1005   Record.push_back(Parts.Part2);
1006   Record.push_back(Parts.Part3);
1007   Record.append(std::begin(Parts.Part4And5), std::end(Parts.Part4And5));
1008   Code = serialization::DECL_MS_GUID;
1009 }
1010
1011 void ASTDeclWriter::VisitUnnamedGlobalConstantDecl(
1012     UnnamedGlobalConstantDecl *D) {
1013   VisitValueDecl(D);
1014   Record.AddAPValue(D->getValue());
1015   Code = serialization::DECL_UNNAMED_GLOBAL_CONSTANT;
1016 }
1017
1018 void ASTDeclWriter::VisitTemplateParamObjectDecl(TemplateParamObjectDecl *D) {
1019   VisitValueDecl(D);
1020   Record.AddAPValue(D->getValue());
1021   Code = serialization::DECL_TEMPLATE_PARAM_OBJECT;
1022 }
1023
1024 void ASTDeclWriter::VisitIndirectFieldDecl(IndirectFieldDecl *D) {
1025   VisitValueDecl(D);
1026   Record.push_back(D->getChainingSize());
1027
1028   for (const auto *P : D->chain())
1029     Record.AddDeclRef(P);
1030   Code = serialization::DECL_INDIRECTFIELD;
1031 }
1032
1033 void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
1034   VisitRedeclarable(D);
1035   VisitDeclaratorDecl(D);
1036   Record.push_back(D->getStorageClass());
1037   Record.push_back(D->getTSCSpec());
1038   Record.push_back(D->getInitStyle());
1039   Record.push_back(D->isARCPseudoStrong());
1040   if (!isa<ParmVarDecl>(D)) {
1041     Record.push_back(D->isThisDeclarationADemotedDefinition());
1042     Record.push_back(D->isExceptionVariable());
1043     Record.push_back(D->isNRVOVariable());
1044     Record.push_back(D->isCXXForRangeDecl());
1045     Record.push_back(D->isObjCForDecl());
1046     Record.push_back(D->isInline());
1047     Record.push_back(D->isInlineSpecified());
1048     Record.push_back(D->isConstexpr());
1049     Record.push_back(D->isInitCapture());
1050     Record.push_back(D->isPreviousDeclInSameBlockScope());
1051     if (const auto *IPD = dyn_cast<ImplicitParamDecl>(D))
1052       Record.push_back(static_cast<unsigned>(IPD->getParameterKind()));
1053     else
1054       Record.push_back(0);
1055     Record.push_back(D->isEscapingByref());
1056   }
1057   Record.push_back(D->getLinkageInternal());
1058
1059   Record.AddVarDeclInit(D);
1060
1061   if (D->hasAttr<BlocksAttr>() && D->getType()->getAsCXXRecordDecl()) {
1062     BlockVarCopyInit Init = Writer.Context->getBlockVarCopyInit(D);
1063     Record.AddStmt(Init.getCopyExpr());
1064     if (Init.getCopyExpr())
1065       Record.push_back(Init.canThrow());
1066   }
1067
1068   if (D->getStorageDuration() == SD_Static) {
1069     bool ModulesCodegen = false;
1070     if (Writer.WritingModule &&
1071         !D->getDescribedVarTemplate() && !D->getMemberSpecializationInfo()) {
1072       // When building a C++20 module interface unit or a partition unit, a
1073       // strong definition in the module interface is provided by the
1074       // compilation of that unit, not by its users. (Inline variables are still
1075       // emitted in module users.)
1076       ModulesCodegen =
1077           (Writer.WritingModule->isInterfaceOrPartition() ||
1078            (D->hasAttr<DLLExportAttr>() &&
1079             Writer.Context->getLangOpts().BuildingPCHWithObjectFile)) &&
1080           Writer.Context->GetGVALinkageForVariable(D) == GVA_StrongExternal;
1081     }
1082     Record.push_back(ModulesCodegen);
1083     if (ModulesCodegen)
1084       Writer.ModularCodegenDecls.push_back(Writer.GetDeclRef(D));
1085   }
1086
1087   enum {
1088     VarNotTemplate = 0, VarTemplate, StaticDataMemberSpecialization
1089   };
1090   if (VarTemplateDecl *TemplD = D->getDescribedVarTemplate()) {
1091     Record.push_back(VarTemplate);
1092     Record.AddDeclRef(TemplD);
1093   } else if (MemberSpecializationInfo *SpecInfo
1094                = D->getMemberSpecializationInfo()) {
1095     Record.push_back(StaticDataMemberSpecialization);
1096     Record.AddDeclRef(SpecInfo->getInstantiatedFrom());
1097     Record.push_back(SpecInfo->getTemplateSpecializationKind());
1098     Record.AddSourceLocation(SpecInfo->getPointOfInstantiation());
1099   } else {
1100     Record.push_back(VarNotTemplate);
1101   }
1102
1103   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1104       !D->hasAttrs() &&
1105       !D->isImplicit() &&
1106       !D->isUsed(false) &&
1107       !D->isInvalidDecl() &&
1108       !D->isReferenced() &&
1109       !D->isTopLevelDeclInObjCContainer() &&
1110       D->getAccess() == AS_none &&
1111       !D->isModulePrivate() &&
1112       !needsAnonymousDeclarationNumber(D) &&
1113       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1114       !D->hasExtInfo() &&
1115       D->getFirstDecl() == D->getMostRecentDecl() &&
1116       D->getKind() == Decl::Var &&
1117       !D->isInline() &&
1118       !D->isConstexpr() &&
1119       !D->isInitCapture() &&
1120       !D->isPreviousDeclInSameBlockScope() &&
1121       !(D->hasAttr<BlocksAttr>() && D->getType()->getAsCXXRecordDecl()) &&
1122       !D->isEscapingByref() &&
1123       D->getStorageDuration() != SD_Static &&
1124       !D->getMemberSpecializationInfo())
1125     AbbrevToUse = Writer.getDeclVarAbbrev();
1126
1127   Code = serialization::DECL_VAR;
1128 }
1129
1130 void ASTDeclWriter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
1131   VisitVarDecl(D);
1132   Code = serialization::DECL_IMPLICIT_PARAM;
1133 }
1134
1135 void ASTDeclWriter::VisitParmVarDecl(ParmVarDecl *D) {
1136   VisitVarDecl(D);
1137   Record.push_back(D->isObjCMethodParameter());
1138   Record.push_back(D->getFunctionScopeDepth());
1139   Record.push_back(D->getFunctionScopeIndex());
1140   Record.push_back(D->getObjCDeclQualifier()); // FIXME: stable encoding
1141   Record.push_back(D->isKNRPromoted());
1142   Record.push_back(D->hasInheritedDefaultArg());
1143   Record.push_back(D->hasUninstantiatedDefaultArg());
1144   if (D->hasUninstantiatedDefaultArg())
1145     Record.AddStmt(D->getUninstantiatedDefaultArg());
1146   Code = serialization::DECL_PARM_VAR;
1147
1148   // If the assumptions about the DECL_PARM_VAR abbrev are true, use it.  Here
1149   // we dynamically check for the properties that we optimize for, but don't
1150   // know are true of all PARM_VAR_DECLs.
1151   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1152       !D->hasAttrs() &&
1153       !D->hasExtInfo() &&
1154       !D->isImplicit() &&
1155       !D->isUsed(false) &&
1156       !D->isInvalidDecl() &&
1157       !D->isReferenced() &&
1158       D->getAccess() == AS_none &&
1159       !D->isModulePrivate() &&
1160       D->getStorageClass() == 0 &&
1161       D->getInitStyle() == VarDecl::CInit && // Can params have anything else?
1162       D->getFunctionScopeDepth() == 0 &&
1163       D->getObjCDeclQualifier() == 0 &&
1164       !D->isKNRPromoted() &&
1165       !D->hasInheritedDefaultArg() &&
1166       D->getInit() == nullptr &&
1167       !D->hasUninstantiatedDefaultArg())  // No default expr.
1168     AbbrevToUse = Writer.getDeclParmVarAbbrev();
1169
1170   // Check things we know are true of *every* PARM_VAR_DECL, which is more than
1171   // just us assuming it.
1172   assert(!D->getTSCSpec() && "PARM_VAR_DECL can't use TLS");
1173   assert(!D->isThisDeclarationADemotedDefinition()
1174          && "PARM_VAR_DECL can't be demoted definition.");
1175   assert(D->getAccess() == AS_none && "PARM_VAR_DECL can't be public/private");
1176   assert(!D->isExceptionVariable() && "PARM_VAR_DECL can't be exception var");
1177   assert(D->getPreviousDecl() == nullptr && "PARM_VAR_DECL can't be redecl");
1178   assert(!D->isStaticDataMember() &&
1179          "PARM_VAR_DECL can't be static data member");
1180 }
1181
1182 void ASTDeclWriter::VisitDecompositionDecl(DecompositionDecl *D) {
1183   // Record the number of bindings first to simplify deserialization.
1184   Record.push_back(D->bindings().size());
1185
1186   VisitVarDecl(D);
1187   for (auto *B : D->bindings())
1188     Record.AddDeclRef(B);
1189   Code = serialization::DECL_DECOMPOSITION;
1190 }
1191
1192 void ASTDeclWriter::VisitBindingDecl(BindingDecl *D) {
1193   VisitValueDecl(D);
1194   Record.AddStmt(D->getBinding());
1195   Code = serialization::DECL_BINDING;
1196 }
1197
1198 void ASTDeclWriter::VisitFileScopeAsmDecl(FileScopeAsmDecl *D) {
1199   VisitDecl(D);
1200   Record.AddStmt(D->getAsmString());
1201   Record.AddSourceLocation(D->getRParenLoc());
1202   Code = serialization::DECL_FILE_SCOPE_ASM;
1203 }
1204
1205 void ASTDeclWriter::VisitTopLevelStmtDecl(TopLevelStmtDecl *D) {
1206   VisitDecl(D);
1207   Record.AddStmt(D->getStmt());
1208   Code = serialization::DECL_TOP_LEVEL_STMT_DECL;
1209 }
1210
1211 void ASTDeclWriter::VisitEmptyDecl(EmptyDecl *D) {
1212   VisitDecl(D);
1213   Code = serialization::DECL_EMPTY;
1214 }
1215
1216 void ASTDeclWriter::VisitLifetimeExtendedTemporaryDecl(
1217     LifetimeExtendedTemporaryDecl *D) {
1218   VisitDecl(D);
1219   Record.AddDeclRef(D->getExtendingDecl());
1220   Record.AddStmt(D->getTemporaryExpr());
1221   Record.push_back(static_cast<bool>(D->getValue()));
1222   if (D->getValue())
1223     Record.AddAPValue(*D->getValue());
1224   Record.push_back(D->getManglingNumber());
1225   Code = serialization::DECL_LIFETIME_EXTENDED_TEMPORARY;
1226 }
1227 void ASTDeclWriter::VisitBlockDecl(BlockDecl *D) {
1228   VisitDecl(D);
1229   Record.AddStmt(D->getBody());
1230   Record.AddTypeSourceInfo(D->getSignatureAsWritten());
1231   Record.push_back(D->param_size());
1232   for (ParmVarDecl *P : D->parameters())
1233     Record.AddDeclRef(P);
1234   Record.push_back(D->isVariadic());
1235   Record.push_back(D->blockMissingReturnType());
1236   Record.push_back(D->isConversionFromLambda());
1237   Record.push_back(D->doesNotEscape());
1238   Record.push_back(D->canAvoidCopyToHeap());
1239   Record.push_back(D->capturesCXXThis());
1240   Record.push_back(D->getNumCaptures());
1241   for (const auto &capture : D->captures()) {
1242     Record.AddDeclRef(capture.getVariable());
1243
1244     unsigned flags = 0;
1245     if (capture.isByRef()) flags |= 1;
1246     if (capture.isNested()) flags |= 2;
1247     if (capture.hasCopyExpr()) flags |= 4;
1248     Record.push_back(flags);
1249
1250     if (capture.hasCopyExpr()) Record.AddStmt(capture.getCopyExpr());
1251   }
1252
1253   Code = serialization::DECL_BLOCK;
1254 }
1255
1256 void ASTDeclWriter::VisitCapturedDecl(CapturedDecl *CD) {
1257   Record.push_back(CD->getNumParams());
1258   VisitDecl(CD);
1259   Record.push_back(CD->getContextParamPosition());
1260   Record.push_back(CD->isNothrow() ? 1 : 0);
1261   // Body is stored by VisitCapturedStmt.
1262   for (unsigned I = 0; I < CD->getNumParams(); ++I)
1263     Record.AddDeclRef(CD->getParam(I));
1264   Code = serialization::DECL_CAPTURED;
1265 }
1266
1267 void ASTDeclWriter::VisitLinkageSpecDecl(LinkageSpecDecl *D) {
1268   static_assert(DeclContext::NumLinkageSpecDeclBits == 4,
1269                 "You need to update the serializer after you change the"
1270                 "LinkageSpecDeclBits");
1271
1272   VisitDecl(D);
1273   Record.push_back(D->getLanguage());
1274   Record.AddSourceLocation(D->getExternLoc());
1275   Record.AddSourceLocation(D->getRBraceLoc());
1276   Code = serialization::DECL_LINKAGE_SPEC;
1277 }
1278
1279 void ASTDeclWriter::VisitExportDecl(ExportDecl *D) {
1280   VisitDecl(D);
1281   Record.AddSourceLocation(D->getRBraceLoc());
1282   Code = serialization::DECL_EXPORT;
1283 }
1284
1285 void ASTDeclWriter::VisitLabelDecl(LabelDecl *D) {
1286   VisitNamedDecl(D);
1287   Record.AddSourceLocation(D->getBeginLoc());
1288   Code = serialization::DECL_LABEL;
1289 }
1290
1291
1292 void ASTDeclWriter::VisitNamespaceDecl(NamespaceDecl *D) {
1293   VisitRedeclarable(D);
1294   VisitNamedDecl(D);
1295   Record.push_back(D->isInline());
1296   Record.push_back(D->isNested());
1297   Record.AddSourceLocation(D->getBeginLoc());
1298   Record.AddSourceLocation(D->getRBraceLoc());
1299
1300   if (D->isOriginalNamespace())
1301     Record.AddDeclRef(D->getAnonymousNamespace());
1302   Code = serialization::DECL_NAMESPACE;
1303
1304   if (Writer.hasChain() && D->isAnonymousNamespace() &&
1305       D == D->getMostRecentDecl()) {
1306     // This is a most recent reopening of the anonymous namespace. If its parent
1307     // is in a previous PCH (or is the TU), mark that parent for update, because
1308     // the original namespace always points to the latest re-opening of its
1309     // anonymous namespace.
1310     Decl *Parent = cast<Decl>(
1311         D->getParent()->getRedeclContext()->getPrimaryContext());
1312     if (Parent->isFromASTFile() || isa<TranslationUnitDecl>(Parent)) {
1313       Writer.DeclUpdates[Parent].push_back(
1314           ASTWriter::DeclUpdate(UPD_CXX_ADDED_ANONYMOUS_NAMESPACE, D));
1315     }
1316   }
1317 }
1318
1319 void ASTDeclWriter::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
1320   VisitRedeclarable(D);
1321   VisitNamedDecl(D);
1322   Record.AddSourceLocation(D->getNamespaceLoc());
1323   Record.AddSourceLocation(D->getTargetNameLoc());
1324   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1325   Record.AddDeclRef(D->getNamespace());
1326   Code = serialization::DECL_NAMESPACE_ALIAS;
1327 }
1328
1329 void ASTDeclWriter::VisitUsingDecl(UsingDecl *D) {
1330   VisitNamedDecl(D);
1331   Record.AddSourceLocation(D->getUsingLoc());
1332   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1333   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
1334   Record.AddDeclRef(D->FirstUsingShadow.getPointer());
1335   Record.push_back(D->hasTypename());
1336   Record.AddDeclRef(Context.getInstantiatedFromUsingDecl(D));
1337   Code = serialization::DECL_USING;
1338 }
1339
1340 void ASTDeclWriter::VisitUsingEnumDecl(UsingEnumDecl *D) {
1341   VisitNamedDecl(D);
1342   Record.AddSourceLocation(D->getUsingLoc());
1343   Record.AddSourceLocation(D->getEnumLoc());
1344   Record.AddTypeSourceInfo(D->getEnumType());
1345   Record.AddDeclRef(D->FirstUsingShadow.getPointer());
1346   Record.AddDeclRef(Context.getInstantiatedFromUsingEnumDecl(D));
1347   Code = serialization::DECL_USING_ENUM;
1348 }
1349
1350 void ASTDeclWriter::VisitUsingPackDecl(UsingPackDecl *D) {
1351   Record.push_back(D->NumExpansions);
1352   VisitNamedDecl(D);
1353   Record.AddDeclRef(D->getInstantiatedFromUsingDecl());
1354   for (auto *E : D->expansions())
1355     Record.AddDeclRef(E);
1356   Code = serialization::DECL_USING_PACK;
1357 }
1358
1359 void ASTDeclWriter::VisitUsingShadowDecl(UsingShadowDecl *D) {
1360   VisitRedeclarable(D);
1361   VisitNamedDecl(D);
1362   Record.AddDeclRef(D->getTargetDecl());
1363   Record.push_back(D->getIdentifierNamespace());
1364   Record.AddDeclRef(D->UsingOrNextShadow);
1365   Record.AddDeclRef(Context.getInstantiatedFromUsingShadowDecl(D));
1366   Code = serialization::DECL_USING_SHADOW;
1367 }
1368
1369 void ASTDeclWriter::VisitConstructorUsingShadowDecl(
1370     ConstructorUsingShadowDecl *D) {
1371   VisitUsingShadowDecl(D);
1372   Record.AddDeclRef(D->NominatedBaseClassShadowDecl);
1373   Record.AddDeclRef(D->ConstructedBaseClassShadowDecl);
1374   Record.push_back(D->IsVirtual);
1375   Code = serialization::DECL_CONSTRUCTOR_USING_SHADOW;
1376 }
1377
1378 void ASTDeclWriter::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
1379   VisitNamedDecl(D);
1380   Record.AddSourceLocation(D->getUsingLoc());
1381   Record.AddSourceLocation(D->getNamespaceKeyLocation());
1382   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1383   Record.AddDeclRef(D->getNominatedNamespace());
1384   Record.AddDeclRef(dyn_cast<Decl>(D->getCommonAncestor()));
1385   Code = serialization::DECL_USING_DIRECTIVE;
1386 }
1387
1388 void ASTDeclWriter::VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
1389   VisitValueDecl(D);
1390   Record.AddSourceLocation(D->getUsingLoc());
1391   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1392   Record.AddDeclarationNameLoc(D->DNLoc, D->getDeclName());
1393   Record.AddSourceLocation(D->getEllipsisLoc());
1394   Code = serialization::DECL_UNRESOLVED_USING_VALUE;
1395 }
1396
1397 void ASTDeclWriter::VisitUnresolvedUsingTypenameDecl(
1398                                                UnresolvedUsingTypenameDecl *D) {
1399   VisitTypeDecl(D);
1400   Record.AddSourceLocation(D->getTypenameLoc());
1401   Record.AddNestedNameSpecifierLoc(D->getQualifierLoc());
1402   Record.AddSourceLocation(D->getEllipsisLoc());
1403   Code = serialization::DECL_UNRESOLVED_USING_TYPENAME;
1404 }
1405
1406 void ASTDeclWriter::VisitUnresolvedUsingIfExistsDecl(
1407     UnresolvedUsingIfExistsDecl *D) {
1408   VisitNamedDecl(D);
1409   Code = serialization::DECL_UNRESOLVED_USING_IF_EXISTS;
1410 }
1411
1412 void ASTDeclWriter::VisitCXXRecordDecl(CXXRecordDecl *D) {
1413   VisitRecordDecl(D);
1414
1415   enum {
1416     CXXRecNotTemplate = 0, CXXRecTemplate, CXXRecMemberSpecialization
1417   };
1418   if (ClassTemplateDecl *TemplD = D->getDescribedClassTemplate()) {
1419     Record.push_back(CXXRecTemplate);
1420     Record.AddDeclRef(TemplD);
1421   } else if (MemberSpecializationInfo *MSInfo
1422                = D->getMemberSpecializationInfo()) {
1423     Record.push_back(CXXRecMemberSpecialization);
1424     Record.AddDeclRef(MSInfo->getInstantiatedFrom());
1425     Record.push_back(MSInfo->getTemplateSpecializationKind());
1426     Record.AddSourceLocation(MSInfo->getPointOfInstantiation());
1427   } else {
1428     Record.push_back(CXXRecNotTemplate);
1429   }
1430
1431   Record.push_back(D->isThisDeclarationADefinition());
1432   if (D->isThisDeclarationADefinition())
1433     Record.AddCXXDefinitionData(D);
1434
1435   // Store (what we currently believe to be) the key function to avoid
1436   // deserializing every method so we can compute it.
1437   if (D->isCompleteDefinition())
1438     Record.AddDeclRef(Context.getCurrentKeyFunction(D));
1439
1440   Code = serialization::DECL_CXX_RECORD;
1441 }
1442
1443 void ASTDeclWriter::VisitCXXMethodDecl(CXXMethodDecl *D) {
1444   VisitFunctionDecl(D);
1445   if (D->isCanonicalDecl()) {
1446     Record.push_back(D->size_overridden_methods());
1447     for (const CXXMethodDecl *MD : D->overridden_methods())
1448       Record.AddDeclRef(MD);
1449   } else {
1450     // We only need to record overridden methods once for the canonical decl.
1451     Record.push_back(0);
1452   }
1453
1454   if (D->getDeclContext() == D->getLexicalDeclContext() &&
1455       D->getFirstDecl() == D->getMostRecentDecl() && !D->isInvalidDecl() &&
1456       !D->hasAttrs() && !D->isTopLevelDeclInObjCContainer() &&
1457       D->getDeclName().getNameKind() == DeclarationName::Identifier &&
1458       !D->hasExtInfo() && !D->hasInheritedPrototype() &&
1459       D->hasWrittenPrototype() &&
1460       D->getTemplatedKind() == FunctionDecl::TK_NonTemplate)
1461     AbbrevToUse = Writer.getDeclCXXMethodAbbrev();
1462
1463   Code = serialization::DECL_CXX_METHOD;
1464 }
1465
1466 void ASTDeclWriter::VisitCXXConstructorDecl(CXXConstructorDecl *D) {
1467   static_assert(DeclContext::NumCXXConstructorDeclBits == 22,
1468                 "You need to update the serializer after you change the "
1469                 "CXXConstructorDeclBits");
1470
1471   Record.push_back(D->getTrailingAllocKind());
1472   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
1473   if (auto Inherited = D->getInheritedConstructor()) {
1474     Record.AddDeclRef(Inherited.getShadowDecl());
1475     Record.AddDeclRef(Inherited.getConstructor());
1476   }
1477
1478   VisitCXXMethodDecl(D);
1479   Code = serialization::DECL_CXX_CONSTRUCTOR;
1480 }
1481
1482 void ASTDeclWriter::VisitCXXDestructorDecl(CXXDestructorDecl *D) {
1483   VisitCXXMethodDecl(D);
1484
1485   Record.AddDeclRef(D->getOperatorDelete());
1486   if (D->getOperatorDelete())
1487     Record.AddStmt(D->getOperatorDeleteThisArg());
1488
1489   Code = serialization::DECL_CXX_DESTRUCTOR;
1490 }
1491
1492 void ASTDeclWriter::VisitCXXConversionDecl(CXXConversionDecl *D) {
1493   addExplicitSpecifier(D->getExplicitSpecifier(), Record);
1494   VisitCXXMethodDecl(D);
1495   Code = serialization::DECL_CXX_CONVERSION;
1496 }
1497
1498 void ASTDeclWriter::VisitImportDecl(ImportDecl *D) {
1499   VisitDecl(D);
1500   Record.push_back(Writer.getSubmoduleID(D->getImportedModule()));
1501   ArrayRef<SourceLocation> IdentifierLocs = D->getIdentifierLocs();
1502   Record.push_back(!IdentifierLocs.empty());
1503   if (IdentifierLocs.empty()) {
1504     Record.AddSourceLocation(D->getEndLoc());
1505     Record.push_back(1);
1506   } else {
1507     for (unsigned I = 0, N = IdentifierLocs.size(); I != N; ++I)
1508       Record.AddSourceLocation(IdentifierLocs[I]);
1509     Record.push_back(IdentifierLocs.size());
1510   }
1511   // Note: the number of source locations must always be the last element in
1512   // the record.
1513   Code = serialization::DECL_IMPORT;
1514 }
1515
1516 void ASTDeclWriter::VisitAccessSpecDecl(AccessSpecDecl *D) {
1517   VisitDecl(D);
1518   Record.AddSourceLocation(D->getColonLoc());
1519   Code = serialization::DECL_ACCESS_SPEC;
1520 }
1521
1522 void ASTDeclWriter::VisitFriendDecl(FriendDecl *D) {
1523   // Record the number of friend type template parameter lists here
1524   // so as to simplify memory allocation during deserialization.
1525   Record.push_back(D->NumTPLists);
1526   VisitDecl(D);
1527   bool hasFriendDecl = D->Friend.is<NamedDecl*>();
1528   Record.push_back(hasFriendDecl);
1529   if (hasFriendDecl)
1530     Record.AddDeclRef(D->getFriendDecl());
1531   else
1532     Record.AddTypeSourceInfo(D->getFriendType());
1533   for (unsigned i = 0; i < D->NumTPLists; ++i)
1534     Record.AddTemplateParameterList(D->getFriendTypeTemplateParameterList(i));
1535   Record.AddDeclRef(D->getNextFriend());
1536   Record.push_back(D->UnsupportedFriend);
1537   Record.AddSourceLocation(D->FriendLoc);
1538   Code = serialization::DECL_FRIEND;
1539 }
1540
1541 void ASTDeclWriter::VisitFriendTemplateDecl(FriendTemplateDecl *D) {
1542   VisitDecl(D);
1543   Record.push_back(D->getNumTemplateParameters());
1544   for (unsigned i = 0, e = D->getNumTemplateParameters(); i != e; ++i)
1545     Record.AddTemplateParameterList(D->getTemplateParameterList(i));
1546   Record.push_back(D->getFriendDecl() != nullptr);
1547   if (D->getFriendDecl())
1548     Record.AddDeclRef(D->getFriendDecl());
1549   else
1550     Record.AddTypeSourceInfo(D->getFriendType());
1551   Record.AddSourceLocation(D->getFriendLoc());
1552   Code = serialization::DECL_FRIEND_TEMPLATE;
1553 }
1554
1555 void ASTDeclWriter::VisitTemplateDecl(TemplateDecl *D) {
1556   VisitNamedDecl(D);
1557
1558   Record.AddTemplateParameterList(D->getTemplateParameters());
1559   Record.AddDeclRef(D->getTemplatedDecl());
1560 }
1561
1562 void ASTDeclWriter::VisitConceptDecl(ConceptDecl *D) {
1563   VisitTemplateDecl(D);
1564   Record.AddStmt(D->getConstraintExpr());
1565   Code = serialization::DECL_CONCEPT;
1566 }
1567
1568 void ASTDeclWriter::VisitImplicitConceptSpecializationDecl(
1569     ImplicitConceptSpecializationDecl *D) {
1570   Record.push_back(D->getTemplateArguments().size());
1571   VisitDecl(D);
1572   for (const TemplateArgument &Arg : D->getTemplateArguments())
1573     Record.AddTemplateArgument(Arg);
1574   Code = serialization::DECL_IMPLICIT_CONCEPT_SPECIALIZATION;
1575 }
1576
1577 void ASTDeclWriter::VisitRequiresExprBodyDecl(RequiresExprBodyDecl *D) {
1578   Code = serialization::DECL_REQUIRES_EXPR_BODY;
1579 }
1580
1581 void ASTDeclWriter::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
1582   VisitRedeclarable(D);
1583
1584   // Emit data to initialize CommonOrPrev before VisitTemplateDecl so that
1585   // getCommonPtr() can be used while this is still initializing.
1586   if (D->isFirstDecl()) {
1587     // This declaration owns the 'common' pointer, so serialize that data now.
1588     Record.AddDeclRef(D->getInstantiatedFromMemberTemplate());
1589     if (D->getInstantiatedFromMemberTemplate())
1590       Record.push_back(D->isMemberSpecialization());
1591   }
1592
1593   VisitTemplateDecl(D);
1594   Record.push_back(D->getIdentifierNamespace());
1595 }
1596
1597 void ASTDeclWriter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
1598   VisitRedeclarableTemplateDecl(D);
1599
1600   if (D->isFirstDecl())
1601     AddTemplateSpecializations(D);
1602   Code = serialization::DECL_CLASS_TEMPLATE;
1603 }
1604
1605 void ASTDeclWriter::VisitClassTemplateSpecializationDecl(
1606                                            ClassTemplateSpecializationDecl *D) {
1607   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1608
1609   VisitCXXRecordDecl(D);
1610
1611   llvm::PointerUnion<ClassTemplateDecl *,
1612                      ClassTemplatePartialSpecializationDecl *> InstFrom
1613     = D->getSpecializedTemplateOrPartial();
1614   if (Decl *InstFromD = InstFrom.dyn_cast<ClassTemplateDecl *>()) {
1615     Record.AddDeclRef(InstFromD);
1616   } else {
1617     Record.AddDeclRef(InstFrom.get<ClassTemplatePartialSpecializationDecl *>());
1618     Record.AddTemplateArgumentList(&D->getTemplateInstantiationArgs());
1619   }
1620
1621   Record.AddTemplateArgumentList(&D->getTemplateArgs());
1622   Record.AddSourceLocation(D->getPointOfInstantiation());
1623   Record.push_back(D->getSpecializationKind());
1624   Record.push_back(D->isCanonicalDecl());
1625
1626   if (D->isCanonicalDecl()) {
1627     // When reading, we'll add it to the folding set of the following template.
1628     Record.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl());
1629   }
1630
1631   // Explicit info.
1632   Record.AddTypeSourceInfo(D->getTypeAsWritten());
1633   if (D->getTypeAsWritten()) {
1634     Record.AddSourceLocation(D->getExternLoc());
1635     Record.AddSourceLocation(D->getTemplateKeywordLoc());
1636   }
1637
1638   Code = serialization::DECL_CLASS_TEMPLATE_SPECIALIZATION;
1639 }
1640
1641 void ASTDeclWriter::VisitClassTemplatePartialSpecializationDecl(
1642                                     ClassTemplatePartialSpecializationDecl *D) {
1643   Record.AddTemplateParameterList(D->getTemplateParameters());
1644   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1645
1646   VisitClassTemplateSpecializationDecl(D);
1647
1648   // These are read/set from/to the first declaration.
1649   if (D->getPreviousDecl() == nullptr) {
1650     Record.AddDeclRef(D->getInstantiatedFromMember());
1651     Record.push_back(D->isMemberSpecialization());
1652   }
1653
1654   Code = serialization::DECL_CLASS_TEMPLATE_PARTIAL_SPECIALIZATION;
1655 }
1656
1657 void ASTDeclWriter::VisitVarTemplateDecl(VarTemplateDecl *D) {
1658   VisitRedeclarableTemplateDecl(D);
1659
1660   if (D->isFirstDecl())
1661     AddTemplateSpecializations(D);
1662   Code = serialization::DECL_VAR_TEMPLATE;
1663 }
1664
1665 void ASTDeclWriter::VisitVarTemplateSpecializationDecl(
1666     VarTemplateSpecializationDecl *D) {
1667   RegisterTemplateSpecialization(D->getSpecializedTemplate(), D);
1668
1669   llvm::PointerUnion<VarTemplateDecl *, VarTemplatePartialSpecializationDecl *>
1670   InstFrom = D->getSpecializedTemplateOrPartial();
1671   if (Decl *InstFromD = InstFrom.dyn_cast<VarTemplateDecl *>()) {
1672     Record.AddDeclRef(InstFromD);
1673   } else {
1674     Record.AddDeclRef(InstFrom.get<VarTemplatePartialSpecializationDecl *>());
1675     Record.AddTemplateArgumentList(&D->getTemplateInstantiationArgs());
1676   }
1677
1678   // Explicit info.
1679   Record.AddTypeSourceInfo(D->getTypeAsWritten());
1680   if (D->getTypeAsWritten()) {
1681     Record.AddSourceLocation(D->getExternLoc());
1682     Record.AddSourceLocation(D->getTemplateKeywordLoc());
1683   }
1684
1685   Record.AddTemplateArgumentList(&D->getTemplateArgs());
1686   Record.AddSourceLocation(D->getPointOfInstantiation());
1687   Record.push_back(D->getSpecializationKind());
1688   Record.push_back(D->IsCompleteDefinition);
1689
1690   VisitVarDecl(D);
1691
1692   Record.push_back(D->isCanonicalDecl());
1693
1694   if (D->isCanonicalDecl()) {
1695     // When reading, we'll add it to the folding set of the following template.
1696     Record.AddDeclRef(D->getSpecializedTemplate()->getCanonicalDecl());
1697   }
1698
1699   Code = serialization::DECL_VAR_TEMPLATE_SPECIALIZATION;
1700 }
1701
1702 void ASTDeclWriter::VisitVarTemplatePartialSpecializationDecl(
1703     VarTemplatePartialSpecializationDecl *D) {
1704   Record.AddTemplateParameterList(D->getTemplateParameters());
1705   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1706
1707   VisitVarTemplateSpecializationDecl(D);
1708
1709   // These are read/set from/to the first declaration.
1710   if (D->getPreviousDecl() == nullptr) {
1711     Record.AddDeclRef(D->getInstantiatedFromMember());
1712     Record.push_back(D->isMemberSpecialization());
1713   }
1714
1715   Code = serialization::DECL_VAR_TEMPLATE_PARTIAL_SPECIALIZATION;
1716 }
1717
1718 void ASTDeclWriter::VisitClassScopeFunctionSpecializationDecl(
1719                                     ClassScopeFunctionSpecializationDecl *D) {
1720   VisitDecl(D);
1721   Record.AddDeclRef(D->getSpecialization());
1722   Record.push_back(D->hasExplicitTemplateArgs());
1723   if (D->hasExplicitTemplateArgs())
1724     Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
1725   Code = serialization::DECL_CLASS_SCOPE_FUNCTION_SPECIALIZATION;
1726 }
1727
1728
1729 void ASTDeclWriter::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
1730   VisitRedeclarableTemplateDecl(D);
1731
1732   if (D->isFirstDecl())
1733     AddTemplateSpecializations(D);
1734   Code = serialization::DECL_FUNCTION_TEMPLATE;
1735 }
1736
1737 void ASTDeclWriter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
1738   Record.push_back(D->hasTypeConstraint());
1739   VisitTypeDecl(D);
1740
1741   Record.push_back(D->wasDeclaredWithTypename());
1742
1743   const TypeConstraint *TC = D->getTypeConstraint();
1744   Record.push_back(TC != nullptr);
1745   if (TC) {
1746     Record.AddNestedNameSpecifierLoc(TC->getNestedNameSpecifierLoc());
1747     Record.AddDeclarationNameInfo(TC->getConceptNameInfo());
1748     Record.AddDeclRef(TC->getNamedConcept());
1749     Record.push_back(TC->getTemplateArgsAsWritten() != nullptr);
1750     if (TC->getTemplateArgsAsWritten())
1751       Record.AddASTTemplateArgumentListInfo(TC->getTemplateArgsAsWritten());
1752     Record.AddStmt(TC->getImmediatelyDeclaredConstraint());
1753     Record.push_back(D->isExpandedParameterPack());
1754     if (D->isExpandedParameterPack())
1755       Record.push_back(D->getNumExpansionParameters());
1756   }
1757
1758   bool OwnsDefaultArg = D->hasDefaultArgument() &&
1759                         !D->defaultArgumentWasInherited();
1760   Record.push_back(OwnsDefaultArg);
1761   if (OwnsDefaultArg)
1762     Record.AddTypeSourceInfo(D->getDefaultArgumentInfo());
1763
1764   Code = serialization::DECL_TEMPLATE_TYPE_PARM;
1765 }
1766
1767 void ASTDeclWriter::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
1768   // For an expanded parameter pack, record the number of expansion types here
1769   // so that it's easier for deserialization to allocate the right amount of
1770   // memory.
1771   Expr *TypeConstraint = D->getPlaceholderTypeConstraint();
1772   Record.push_back(!!TypeConstraint);
1773   if (D->isExpandedParameterPack())
1774     Record.push_back(D->getNumExpansionTypes());
1775
1776   VisitDeclaratorDecl(D);
1777   // TemplateParmPosition.
1778   Record.push_back(D->getDepth());
1779   Record.push_back(D->getPosition());
1780   if (TypeConstraint)
1781     Record.AddStmt(TypeConstraint);
1782
1783   if (D->isExpandedParameterPack()) {
1784     for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {
1785       Record.AddTypeRef(D->getExpansionType(I));
1786       Record.AddTypeSourceInfo(D->getExpansionTypeSourceInfo(I));
1787     }
1788
1789     Code = serialization::DECL_EXPANDED_NON_TYPE_TEMPLATE_PARM_PACK;
1790   } else {
1791     // Rest of NonTypeTemplateParmDecl.
1792     Record.push_back(D->isParameterPack());
1793     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1794                           !D->defaultArgumentWasInherited();
1795     Record.push_back(OwnsDefaultArg);
1796     if (OwnsDefaultArg)
1797       Record.AddStmt(D->getDefaultArgument());
1798     Code = serialization::DECL_NON_TYPE_TEMPLATE_PARM;
1799   }
1800 }
1801
1802 void ASTDeclWriter::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
1803   // For an expanded parameter pack, record the number of expansion types here
1804   // so that it's easier for deserialization to allocate the right amount of
1805   // memory.
1806   if (D->isExpandedParameterPack())
1807     Record.push_back(D->getNumExpansionTemplateParameters());
1808
1809   VisitTemplateDecl(D);
1810   // TemplateParmPosition.
1811   Record.push_back(D->getDepth());
1812   Record.push_back(D->getPosition());
1813
1814   if (D->isExpandedParameterPack()) {
1815     for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
1816          I != N; ++I)
1817       Record.AddTemplateParameterList(D->getExpansionTemplateParameters(I));
1818     Code = serialization::DECL_EXPANDED_TEMPLATE_TEMPLATE_PARM_PACK;
1819   } else {
1820     // Rest of TemplateTemplateParmDecl.
1821     Record.push_back(D->isParameterPack());
1822     bool OwnsDefaultArg = D->hasDefaultArgument() &&
1823                           !D->defaultArgumentWasInherited();
1824     Record.push_back(OwnsDefaultArg);
1825     if (OwnsDefaultArg)
1826       Record.AddTemplateArgumentLoc(D->getDefaultArgument());
1827     Code = serialization::DECL_TEMPLATE_TEMPLATE_PARM;
1828   }
1829 }
1830
1831 void ASTDeclWriter::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
1832   VisitRedeclarableTemplateDecl(D);
1833   Code = serialization::DECL_TYPE_ALIAS_TEMPLATE;
1834 }
1835
1836 void ASTDeclWriter::VisitStaticAssertDecl(StaticAssertDecl *D) {
1837   VisitDecl(D);
1838   Record.AddStmt(D->getAssertExpr());
1839   Record.push_back(D->isFailed());
1840   Record.AddStmt(D->getMessage());
1841   Record.AddSourceLocation(D->getRParenLoc());
1842   Code = serialization::DECL_STATIC_ASSERT;
1843 }
1844
1845 /// Emit the DeclContext part of a declaration context decl.
1846 void ASTDeclWriter::VisitDeclContext(DeclContext *DC) {
1847   static_assert(DeclContext::NumDeclContextBits == 13,
1848                 "You need to update the serializer after you change the "
1849                 "DeclContextBits");
1850
1851   Record.AddOffset(Writer.WriteDeclContextLexicalBlock(Context, DC));
1852   Record.AddOffset(Writer.WriteDeclContextVisibleBlock(Context, DC));
1853 }
1854
1855 const Decl *ASTWriter::getFirstLocalDecl(const Decl *D) {
1856   assert(IsLocalDecl(D) && "expected a local declaration");
1857
1858   const Decl *Canon = D->getCanonicalDecl();
1859   if (IsLocalDecl(Canon))
1860     return Canon;
1861
1862   const Decl *&CacheEntry = FirstLocalDeclCache[Canon];
1863   if (CacheEntry)
1864     return CacheEntry;
1865
1866   for (const Decl *Redecl = D; Redecl; Redecl = Redecl->getPreviousDecl())
1867     if (IsLocalDecl(Redecl))
1868       D = Redecl;
1869   return CacheEntry = D;
1870 }
1871
1872 template <typename T>
1873 void ASTDeclWriter::VisitRedeclarable(Redeclarable<T> *D) {
1874   T *First = D->getFirstDecl();
1875   T *MostRecent = First->getMostRecentDecl();
1876   T *DAsT = static_cast<T *>(D);
1877   if (MostRecent != First) {
1878     assert(isRedeclarableDeclKind(DAsT->getKind()) &&
1879            "Not considered redeclarable?");
1880
1881     Record.AddDeclRef(First);
1882
1883     // Write out a list of local redeclarations of this declaration if it's the
1884     // first local declaration in the chain.
1885     const Decl *FirstLocal = Writer.getFirstLocalDecl(DAsT);
1886     if (DAsT == FirstLocal) {
1887       // Emit a list of all imported first declarations so that we can be sure
1888       // that all redeclarations visible to this module are before D in the
1889       // redecl chain.
1890       unsigned I = Record.size();
1891       Record.push_back(0);
1892       if (Writer.Chain)
1893         AddFirstDeclFromEachModule(DAsT, /*IncludeLocal*/false);
1894       // This is the number of imported first declarations + 1.
1895       Record[I] = Record.size() - I;
1896
1897       // Collect the set of local redeclarations of this declaration, from
1898       // newest to oldest.
1899       ASTWriter::RecordData LocalRedecls;
1900       ASTRecordWriter LocalRedeclWriter(Record, LocalRedecls);
1901       for (const Decl *Prev = FirstLocal->getMostRecentDecl();
1902            Prev != FirstLocal; Prev = Prev->getPreviousDecl())
1903         if (!Prev->isFromASTFile())
1904           LocalRedeclWriter.AddDeclRef(Prev);
1905
1906       // If we have any redecls, write them now as a separate record preceding
1907       // the declaration itself.
1908       if (LocalRedecls.empty())
1909         Record.push_back(0);
1910       else
1911         Record.AddOffset(LocalRedeclWriter.Emit(LOCAL_REDECLARATIONS));
1912     } else {
1913       Record.push_back(0);
1914       Record.AddDeclRef(FirstLocal);
1915     }
1916
1917     // Make sure that we serialize both the previous and the most-recent
1918     // declarations, which (transitively) ensures that all declarations in the
1919     // chain get serialized.
1920     //
1921     // FIXME: This is not correct; when we reach an imported declaration we
1922     // won't emit its previous declaration.
1923     (void)Writer.GetDeclRef(D->getPreviousDecl());
1924     (void)Writer.GetDeclRef(MostRecent);
1925   } else {
1926     // We use the sentinel value 0 to indicate an only declaration.
1927     Record.push_back(0);
1928   }
1929 }
1930
1931 void ASTDeclWriter::VisitHLSLBufferDecl(HLSLBufferDecl *D) {
1932   VisitNamedDecl(D);
1933   VisitDeclContext(D);
1934   Record.push_back(D->isCBuffer());
1935   Record.AddSourceLocation(D->getLocStart());
1936   Record.AddSourceLocation(D->getLBraceLoc());
1937   Record.AddSourceLocation(D->getRBraceLoc());
1938
1939   Code = serialization::DECL_HLSL_BUFFER;
1940 }
1941
1942 void ASTDeclWriter::VisitOMPThreadPrivateDecl(OMPThreadPrivateDecl *D) {
1943   Record.writeOMPChildren(D->Data);
1944   VisitDecl(D);
1945   Code = serialization::DECL_OMP_THREADPRIVATE;
1946 }
1947
1948 void ASTDeclWriter::VisitOMPAllocateDecl(OMPAllocateDecl *D) {
1949   Record.writeOMPChildren(D->Data);
1950   VisitDecl(D);
1951   Code = serialization::DECL_OMP_ALLOCATE;
1952 }
1953
1954 void ASTDeclWriter::VisitOMPRequiresDecl(OMPRequiresDecl *D) {
1955   Record.writeOMPChildren(D->Data);
1956   VisitDecl(D);
1957   Code = serialization::DECL_OMP_REQUIRES;
1958 }
1959
1960 void ASTDeclWriter::VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D) {
1961   static_assert(DeclContext::NumOMPDeclareReductionDeclBits == 2,
1962                 "You need to update the serializer after you change the "
1963                 "NumOMPDeclareReductionDeclBits");
1964
1965   VisitValueDecl(D);
1966   Record.AddSourceLocation(D->getBeginLoc());
1967   Record.AddStmt(D->getCombinerIn());
1968   Record.AddStmt(D->getCombinerOut());
1969   Record.AddStmt(D->getCombiner());
1970   Record.AddStmt(D->getInitOrig());
1971   Record.AddStmt(D->getInitPriv());
1972   Record.AddStmt(D->getInitializer());
1973   Record.push_back(D->getInitializerKind());
1974   Record.AddDeclRef(D->getPrevDeclInScope());
1975   Code = serialization::DECL_OMP_DECLARE_REDUCTION;
1976 }
1977
1978 void ASTDeclWriter::VisitOMPDeclareMapperDecl(OMPDeclareMapperDecl *D) {
1979   Record.writeOMPChildren(D->Data);
1980   VisitValueDecl(D);
1981   Record.AddDeclarationName(D->getVarName());
1982   Record.AddDeclRef(D->getPrevDeclInScope());
1983   Code = serialization::DECL_OMP_DECLARE_MAPPER;
1984 }
1985
1986 void ASTDeclWriter::VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D) {
1987   VisitVarDecl(D);
1988   Code = serialization::DECL_OMP_CAPTUREDEXPR;
1989 }
1990
1991 //===----------------------------------------------------------------------===//
1992 // ASTWriter Implementation
1993 //===----------------------------------------------------------------------===//
1994
1995 void ASTWriter::WriteDeclAbbrevs() {
1996   using namespace llvm;
1997
1998   std::shared_ptr<BitCodeAbbrev> Abv;
1999
2000   // Abbreviation for DECL_FIELD
2001   Abv = std::make_shared<BitCodeAbbrev>();
2002   Abv->Add(BitCodeAbbrevOp(serialization::DECL_FIELD));
2003   // Decl
2004   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2005   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2006   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2007   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2008   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2009   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2010   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2011   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2012   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
2013   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));  // ModuleOwnershipKind
2014   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2015   // NamedDecl
2016   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2017   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2018   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2019   // ValueDecl
2020   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2021   // DeclaratorDecl
2022   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
2023   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
2024   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
2025   // FieldDecl
2026   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
2027   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
2028   // Type Source Info
2029   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2030   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2031   DeclFieldAbbrev = Stream.EmitAbbrev(std::move(Abv));
2032
2033   // Abbreviation for DECL_OBJC_IVAR
2034   Abv = std::make_shared<BitCodeAbbrev>();
2035   Abv->Add(BitCodeAbbrevOp(serialization::DECL_OBJC_IVAR));
2036   // Decl
2037   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2038   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2039   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2040   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2041   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2042   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2043   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2044   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2045   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));  // AccessSpecifier
2046   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));  // ModuleOwnershipKind
2047   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2048   // NamedDecl
2049   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2050   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2051   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2052   // ValueDecl
2053   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2054   // DeclaratorDecl
2055   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
2056   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
2057   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
2058   // FieldDecl
2059   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isMutable
2060   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
2061   // ObjC Ivar
2062   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getAccessControl
2063   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getSynthesize
2064   // Type Source Info
2065   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2066   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2067   DeclObjCIvarAbbrev = Stream.EmitAbbrev(std::move(Abv));
2068
2069   // Abbreviation for DECL_ENUM
2070   Abv = std::make_shared<BitCodeAbbrev>();
2071   Abv->Add(BitCodeAbbrevOp(serialization::DECL_ENUM));
2072   // Redeclarable
2073   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2074   // Decl
2075   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2076   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2077   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2078   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2079   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2080   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2081   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2082   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2083   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2084   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // ModuleOwnershipKind
2085   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2086   // NamedDecl
2087   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2088   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2089   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2090   // TypeDecl
2091   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
2092   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
2093   // TagDecl
2094   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
2095   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
2096   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
2097   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
2098   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
2099   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
2100   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2101   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2102   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
2103   // EnumDecl
2104   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddTypeRef
2105   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IntegerType
2106   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getPromotionType
2107   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumPositiveBits
2108   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getNumNegativeBits
2109   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScoped
2110   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isScopedUsingClassTag
2111   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isFixed
2112   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));// ODRHash
2113   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InstantiatedMembEnum
2114   // DC
2115   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
2116   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
2117   DeclEnumAbbrev = Stream.EmitAbbrev(std::move(Abv));
2118
2119   // Abbreviation for DECL_RECORD
2120   Abv = std::make_shared<BitCodeAbbrev>();
2121   Abv->Add(BitCodeAbbrevOp(serialization::DECL_RECORD));
2122   // Redeclarable
2123   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2124   // Decl
2125   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2126   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2127   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2128   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2129   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2130   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2131   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2132   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2133   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2134   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // ModuleOwnershipKind
2135   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2136   // NamedDecl
2137   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2138   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2139   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2140   // TypeDecl
2141   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
2142   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
2143   // TagDecl
2144   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // IdentifierNamespace
2145   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // getTagKind
2146   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCompleteDefinition
2147   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // EmbeddedInDeclarator
2148   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsFreeStanding
2149   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsCompleteDefinitionRequired
2150   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2151   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
2152   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
2153   // RecordDecl
2154   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // FlexibleArrayMember
2155   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // AnonymousStructUnion
2156   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasObjectMember
2157   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasVolatileMember
2158
2159   // isNonTrivialToPrimitiveDefaultInitialize
2160   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2161   // isNonTrivialToPrimitiveCopy
2162   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2163   // isNonTrivialToPrimitiveDestroy
2164   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2165   // hasNonTrivialToPrimitiveDefaultInitializeCUnion
2166   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2167   // hasNonTrivialToPrimitiveDestructCUnion
2168   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2169   // hasNonTrivialToPrimitiveCopyCUnion
2170   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2171   // isParamDestroyedInCallee
2172   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2173   // getArgPassingRestrictions
2174   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2));
2175   // ODRHash
2176   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 26));
2177
2178   // DC
2179   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
2180   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
2181   DeclRecordAbbrev = Stream.EmitAbbrev(std::move(Abv));
2182
2183   // Abbreviation for DECL_PARM_VAR
2184   Abv = std::make_shared<BitCodeAbbrev>();
2185   Abv->Add(BitCodeAbbrevOp(serialization::DECL_PARM_VAR));
2186   // Redeclarable
2187   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2188   // Decl
2189   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2190   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2191   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2192   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2193   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2194   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2195   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2196   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2197   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2198   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // ModuleOwnershipKind
2199   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2200   // NamedDecl
2201   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2202   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2203   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2204   // ValueDecl
2205   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2206   // DeclaratorDecl
2207   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
2208   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
2209   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
2210   // VarDecl
2211   Abv->Add(BitCodeAbbrevOp(0));                       // SClass
2212   Abv->Add(BitCodeAbbrevOp(0));                       // TSCSpec
2213   Abv->Add(BitCodeAbbrevOp(0));                       // InitStyle
2214   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isARCPseudoStrong
2215   Abv->Add(BitCodeAbbrevOp(0));                       // Linkage
2216   Abv->Add(BitCodeAbbrevOp(0));                       // HasInit
2217   Abv->Add(BitCodeAbbrevOp(0));                   // HasMemberSpecializationInfo
2218   // ParmVarDecl
2219   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsObjCMethodParameter
2220   Abv->Add(BitCodeAbbrevOp(0));                       // ScopeDepth
2221   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ScopeIndex
2222   Abv->Add(BitCodeAbbrevOp(0));                       // ObjCDeclQualifier
2223   Abv->Add(BitCodeAbbrevOp(0));                       // KNRPromoted
2224   Abv->Add(BitCodeAbbrevOp(0));                       // HasInheritedDefaultArg
2225   Abv->Add(BitCodeAbbrevOp(0));                   // HasUninstantiatedDefaultArg
2226   // Type Source Info
2227   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2228   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2229   DeclParmVarAbbrev = Stream.EmitAbbrev(std::move(Abv));
2230
2231   // Abbreviation for DECL_TYPEDEF
2232   Abv = std::make_shared<BitCodeAbbrev>();
2233   Abv->Add(BitCodeAbbrevOp(serialization::DECL_TYPEDEF));
2234   // Redeclarable
2235   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2236   // Decl
2237   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2238   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2239   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2240   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2241   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2242   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isUsed
2243   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isReferenced
2244   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2245   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // C++ AccessSpecifier
2246   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // ModuleOwnershipKind
2247   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2248   // NamedDecl
2249   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2250   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2251   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2252   // TypeDecl
2253   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
2254   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type Ref
2255   // TypedefDecl
2256   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2257   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2258   DeclTypedefAbbrev = Stream.EmitAbbrev(std::move(Abv));
2259
2260   // Abbreviation for DECL_VAR
2261   Abv = std::make_shared<BitCodeAbbrev>();
2262   Abv->Add(BitCodeAbbrevOp(serialization::DECL_VAR));
2263   // Redeclarable
2264   Abv->Add(BitCodeAbbrevOp(0));                       // No redeclaration
2265   // Decl
2266   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclContext
2267   Abv->Add(BitCodeAbbrevOp(0));                       // LexicalDeclContext
2268   Abv->Add(BitCodeAbbrevOp(0));                       // isInvalidDecl
2269   Abv->Add(BitCodeAbbrevOp(0));                       // HasAttrs
2270   Abv->Add(BitCodeAbbrevOp(0));                       // isImplicit
2271   Abv->Add(BitCodeAbbrevOp(0));                       // isUsed
2272   Abv->Add(BitCodeAbbrevOp(0));                       // isReferenced
2273   Abv->Add(BitCodeAbbrevOp(0));                   // TopLevelDeclInObjCContainer
2274   Abv->Add(BitCodeAbbrevOp(AS_none));                 // C++ AccessSpecifier
2275   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // ModuleOwnershipKind
2276   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // SubmoduleID
2277   // NamedDecl
2278   Abv->Add(BitCodeAbbrevOp(0));                       // NameKind = Identifier
2279   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Name
2280   Abv->Add(BitCodeAbbrevOp(0));                       // AnonDeclNumber
2281   // ValueDecl
2282   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2283   // DeclaratorDecl
2284   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // InnerStartLoc
2285   Abv->Add(BitCodeAbbrevOp(0));                       // hasExtInfo
2286   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TSIType
2287   // VarDecl
2288   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // SClass
2289   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // TSCSpec
2290   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // InitStyle
2291   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isARCPseudoStrong
2292   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsThisDeclarationADemotedDefinition
2293   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isExceptionVariable
2294   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isNRVOVariable
2295   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCXXForRangeDecl
2296   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isObjCForDecl
2297   Abv->Add(BitCodeAbbrevOp(0));                         // isInline
2298   Abv->Add(BitCodeAbbrevOp(0));                         // isInlineSpecified
2299   Abv->Add(BitCodeAbbrevOp(0));                         // isConstexpr
2300   Abv->Add(BitCodeAbbrevOp(0));                         // isInitCapture
2301   Abv->Add(BitCodeAbbrevOp(0));                         // isPrevDeclInSameScope
2302   Abv->Add(BitCodeAbbrevOp(0));                         // ImplicitParamKind
2303   Abv->Add(BitCodeAbbrevOp(0));                         // EscapingByref
2304   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
2305   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // HasConstant*
2306   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // VarKind (local enum)
2307   // Type Source Info
2308   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2309   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
2310   DeclVarAbbrev = Stream.EmitAbbrev(std::move(Abv));
2311
2312   // Abbreviation for DECL_CXX_METHOD
2313   Abv = std::make_shared<BitCodeAbbrev>();
2314   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CXX_METHOD));
2315   // RedeclarableDecl
2316   Abv->Add(BitCodeAbbrevOp(0));                         // CanonicalDecl
2317   // FIXME: Implement abbreviation for other template kinds.
2318   Abv->Add(BitCodeAbbrevOp(FunctionDecl::TK_NonTemplate)); // TemplateKind
2319   // Decl
2320   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // DeclContext
2321   Abv->Add(BitCodeAbbrevOp(0));                         // LexicalDeclContext
2322   Abv->Add(BitCodeAbbrevOp(0));                         // Invalid
2323   Abv->Add(BitCodeAbbrevOp(0));                         // HasAttrs
2324   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Implicit
2325   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Used
2326   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Referenced
2327   Abv->Add(BitCodeAbbrevOp(0));                         // InObjCContainer
2328   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // Access
2329   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // ModuleOwnershipKind
2330   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SubmoduleID
2331   // NamedDecl
2332   Abv->Add(BitCodeAbbrevOp(DeclarationName::Identifier)); // NameKind
2333   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Identifier
2334   Abv->Add(BitCodeAbbrevOp(0));                         // AnonDeclNumber
2335   // ValueDecl
2336   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Type
2337   // DeclaratorDecl
2338   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // InnerLocStart
2339   Abv->Add(BitCodeAbbrevOp(0));                         // HasExtInfo
2340   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // TSIType
2341   // FunctionDecl
2342   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 11)); // IDNS
2343   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // StorageClass
2344   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Inline
2345   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // InlineSpecified
2346   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // VirtualAsWritten
2347   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Pure
2348   Abv->Add(BitCodeAbbrevOp(0));                         // HasInheritedProto
2349   Abv->Add(BitCodeAbbrevOp(1));                         // HasWrittenProto
2350   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Deleted
2351   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Trivial
2352   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // TrivialForCall
2353   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Defaulted
2354   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ExplicitlyDefaulted
2355   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsIneligibleOrNotSelected
2356   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ImplicitReturnZero
2357   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // Constexpr
2358   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // UsesSEHTry
2359   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // SkippedBody
2360   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // MultiVersion
2361   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // LateParsed
2362   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // FriendConstraintRefersToEnclosingTemplate
2363   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // Linkage
2364   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LocEnd
2365   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Default
2366   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32)); // ODRHash
2367   // This Array slurps the rest of the record. Fortunately we want to encode
2368   // (nearly) all the remaining (variable number of) fields in the same way.
2369   //
2370   // This is:
2371   //         NumParams and Params[] from FunctionDecl, and
2372   //         NumOverriddenMethods, OverriddenMethods[] from CXXMethodDecl.
2373   //
2374   //  Add an AbbrevOp for 'size then elements' and use it here.
2375   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2376   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2377   DeclCXXMethodAbbrev = Stream.EmitAbbrev(std::move(Abv));
2378
2379   unsigned ExprDependenceBits = llvm::BitWidth<ExprDependence>;
2380   // Abbreviation for EXPR_DECL_REF
2381   Abv = std::make_shared<BitCodeAbbrev>();
2382   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_DECL_REF));
2383   //Stmt
2384   // Expr
2385   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2386   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, ExprDependenceBits));
2387   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2388   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2389   //DeclRefExpr
2390   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HasQualifier
2391   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //GetDeclFound
2392   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ExplicitTemplateArgs
2393   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //HadMultipleCandidates
2394   Abv->Add(BitCodeAbbrevOp(0)); // RefersToEnclosingVariableOrCapture
2395   Abv->Add(BitCodeAbbrevOp(0)); // NonOdrUseReason
2396   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // DeclRef
2397   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2398   DeclRefExprAbbrev = Stream.EmitAbbrev(std::move(Abv));
2399
2400   // Abbreviation for EXPR_INTEGER_LITERAL
2401   Abv = std::make_shared<BitCodeAbbrev>();
2402   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_INTEGER_LITERAL));
2403   //Stmt
2404   // Expr
2405   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2406   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, ExprDependenceBits));
2407   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2408   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2409   //Integer Literal
2410   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2411   Abv->Add(BitCodeAbbrevOp(32));                      // Bit Width
2412   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Value
2413   IntegerLiteralAbbrev = Stream.EmitAbbrev(std::move(Abv));
2414
2415   // Abbreviation for EXPR_CHARACTER_LITERAL
2416   Abv = std::make_shared<BitCodeAbbrev>();
2417   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_CHARACTER_LITERAL));
2418   //Stmt
2419   // Expr
2420   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2421   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, ExprDependenceBits));
2422   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2423   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2424   //Character Literal
2425   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // getValue
2426   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Location
2427   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // getKind
2428   CharacterLiteralAbbrev = Stream.EmitAbbrev(std::move(Abv));
2429
2430   // Abbreviation for EXPR_IMPLICIT_CAST
2431   Abv = std::make_shared<BitCodeAbbrev>();
2432   Abv->Add(BitCodeAbbrevOp(serialization::EXPR_IMPLICIT_CAST));
2433   // Stmt
2434   // Expr
2435   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Type
2436   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, ExprDependenceBits));
2437   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
2438   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
2439   // CastExpr
2440   Abv->Add(BitCodeAbbrevOp(0)); // PathSize
2441   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // HasFPFeatures
2442   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 6)); // CastKind
2443   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // PartOfExplicitCast
2444   // ImplicitCastExpr
2445   ExprImplicitCastAbbrev = Stream.EmitAbbrev(std::move(Abv));
2446
2447   Abv = std::make_shared<BitCodeAbbrev>();
2448   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_LEXICAL));
2449   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2450   DeclContextLexicalAbbrev = Stream.EmitAbbrev(std::move(Abv));
2451
2452   Abv = std::make_shared<BitCodeAbbrev>();
2453   Abv->Add(BitCodeAbbrevOp(serialization::DECL_CONTEXT_VISIBLE));
2454   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2455   DeclContextVisibleLookupAbbrev = Stream.EmitAbbrev(std::move(Abv));
2456 }
2457
2458 /// isRequiredDecl - Check if this is a "required" Decl, which must be seen by
2459 /// consumers of the AST.
2460 ///
2461 /// Such decls will always be deserialized from the AST file, so we would like
2462 /// this to be as restrictive as possible. Currently the predicate is driven by
2463 /// code generation requirements, if other clients have a different notion of
2464 /// what is "required" then we may have to consider an alternate scheme where
2465 /// clients can iterate over the top-level decls and get information on them,
2466 /// without necessary deserializing them. We could explicitly require such
2467 /// clients to use a separate API call to "realize" the decl. This should be
2468 /// relatively painless since they would presumably only do it for top-level
2469 /// decls.
2470 static bool isRequiredDecl(const Decl *D, ASTContext &Context,
2471                            bool WritingModule) {
2472   // An ObjCMethodDecl is never considered as "required" because its
2473   // implementation container always is.
2474
2475   // File scoped assembly or obj-c or OMP declare target implementation must be
2476   // seen.
2477   if (isa<FileScopeAsmDecl, TopLevelStmtDecl, ObjCImplDecl>(D))
2478     return true;
2479
2480   if (WritingModule && isPartOfPerModuleInitializer(D)) {
2481     // These declarations are part of the module initializer, and are emitted
2482     // if and when the module is imported, rather than being emitted eagerly.
2483     return false;
2484   }
2485
2486   return Context.DeclMustBeEmitted(D);
2487 }
2488
2489 void ASTWriter::WriteDecl(ASTContext &Context, Decl *D) {
2490   PrettyDeclStackTraceEntry CrashInfo(Context, D, SourceLocation(),
2491                                       "serializing");
2492
2493   // Determine the ID for this declaration.
2494   serialization::DeclID ID;
2495   assert(!D->isFromASTFile() && "should not be emitting imported decl");
2496   serialization::DeclID &IDR = DeclIDs[D];
2497   if (IDR == 0)
2498     IDR = NextDeclID++;
2499
2500   ID = IDR;
2501
2502   assert(ID >= FirstDeclID && "invalid decl ID");
2503
2504   RecordData Record;
2505   ASTDeclWriter W(*this, Context, Record);
2506
2507   // Build a record for this declaration
2508   W.Visit(D);
2509
2510   // Emit this declaration to the bitstream.
2511   uint64_t Offset = W.Emit(D);
2512
2513   // Record the offset for this declaration
2514   SourceLocation Loc = D->getLocation();
2515   unsigned Index = ID - FirstDeclID;
2516   if (DeclOffsets.size() == Index)
2517     DeclOffsets.emplace_back(getAdjustedLocation(Loc), Offset,
2518                              DeclTypesBlockStartOffset);
2519   else if (DeclOffsets.size() < Index) {
2520     // FIXME: Can/should this happen?
2521     DeclOffsets.resize(Index+1);
2522     DeclOffsets[Index].setLocation(getAdjustedLocation(Loc));
2523     DeclOffsets[Index].setBitOffset(Offset, DeclTypesBlockStartOffset);
2524   } else {
2525     llvm_unreachable("declarations should be emitted in ID order");
2526   }
2527
2528   SourceManager &SM = Context.getSourceManager();
2529   if (Loc.isValid() && SM.isLocalSourceLocation(Loc))
2530     associateDeclWithFile(D, ID);
2531
2532   // Note declarations that should be deserialized eagerly so that we can add
2533   // them to a record in the AST file later.
2534   if (isRequiredDecl(D, Context, WritingModule))
2535     EagerlyDeserializedDecls.push_back(ID);
2536 }
2537
2538 void ASTRecordWriter::AddFunctionDefinition(const FunctionDecl *FD) {
2539   // Switch case IDs are per function body.
2540   Writer->ClearSwitchCaseIDs();
2541
2542   assert(FD->doesThisDeclarationHaveABody());
2543   bool ModulesCodegen = false;
2544   if (!FD->isDependentContext()) {
2545     std::optional<GVALinkage> Linkage;
2546     if (Writer->WritingModule &&
2547         Writer->WritingModule->isInterfaceOrPartition()) {
2548       // When building a C++20 module interface unit or a partition unit, a
2549       // strong definition in the module interface is provided by the
2550       // compilation of that unit, not by its users. (Inline functions are still
2551       // emitted in module users.)
2552       Linkage = Writer->Context->GetGVALinkageForFunction(FD);
2553       ModulesCodegen = *Linkage == GVA_StrongExternal;
2554     }
2555     if (Writer->Context->getLangOpts().ModulesCodegen ||
2556         (FD->hasAttr<DLLExportAttr>() &&
2557          Writer->Context->getLangOpts().BuildingPCHWithObjectFile)) {
2558
2559       // Under -fmodules-codegen, codegen is performed for all non-internal,
2560       // non-always_inline functions, unless they are available elsewhere.
2561       if (!FD->hasAttr<AlwaysInlineAttr>()) {
2562         if (!Linkage)
2563           Linkage = Writer->Context->GetGVALinkageForFunction(FD);
2564         ModulesCodegen =
2565             *Linkage != GVA_Internal && *Linkage != GVA_AvailableExternally;
2566       }
2567     }
2568   }
2569   Record->push_back(ModulesCodegen);
2570   if (ModulesCodegen)
2571     Writer->ModularCodegenDecls.push_back(Writer->GetDeclRef(FD));
2572   if (auto *CD = dyn_cast<CXXConstructorDecl>(FD)) {
2573     Record->push_back(CD->getNumCtorInitializers());
2574     if (CD->getNumCtorInitializers())
2575       AddCXXCtorInitializers(llvm::ArrayRef(CD->init_begin(), CD->init_end()));
2576   }
2577   AddStmt(FD->getBody());
2578 }