Coverage Report

Created: 2020-10-24 06:27

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
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//===--- ObjectFilePCHContainerOperations.cpp -----------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "clang/CodeGen/ObjectFilePCHContainerOperations.h"
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#include "CGDebugInfo.h"
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#include "CodeGenModule.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/AST/DeclObjC.h"
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#include "clang/AST/Expr.h"
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#include "clang/AST/RecursiveASTVisitor.h"
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#include "clang/Basic/CodeGenOptions.h"
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#include "clang/Basic/Diagnostic.h"
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#include "clang/Basic/TargetInfo.h"
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#include "clang/CodeGen/BackendUtil.h"
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#include "clang/Frontend/CompilerInstance.h"
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#include "clang/Lex/HeaderSearch.h"
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#include "clang/Lex/Preprocessor.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/Bitstream/BitstreamReader.h"
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#include "llvm/DebugInfo/DWARF/DWARFContext.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/Module.h"
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#include "llvm/Object/COFF.h"
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#include "llvm/Object/ObjectFile.h"
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#include "llvm/Support/Path.h"
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#include "llvm/Support/TargetRegistry.h"
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#include <memory>
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#include <utility>
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using namespace clang;
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#define DEBUG_TYPE "pchcontainer"
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namespace {
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class PCHContainerGenerator : public ASTConsumer {
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  DiagnosticsEngine &Diags;
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  const std::string MainFileName;
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  const std::string OutputFileName;
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  ASTContext *Ctx;
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  ModuleMap &MMap;
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  const HeaderSearchOptions &HeaderSearchOpts;
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  const PreprocessorOptions &PreprocessorOpts;
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  CodeGenOptions CodeGenOpts;
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  const TargetOptions TargetOpts;
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  const LangOptions LangOpts;
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  std::unique_ptr<llvm::LLVMContext> VMContext;
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  std::unique_ptr<llvm::Module> M;
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  std::unique_ptr<CodeGen::CodeGenModule> Builder;
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  std::unique_ptr<raw_pwrite_stream> OS;
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  std::shared_ptr<PCHBuffer> Buffer;
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  /// Visit every type and emit debug info for it.
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  struct DebugTypeVisitor : public RecursiveASTVisitor<DebugTypeVisitor> {
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    clang::CodeGen::CGDebugInfo &DI;
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    ASTContext &Ctx;
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    DebugTypeVisitor(clang::CodeGen::CGDebugInfo &DI, ASTContext &Ctx)
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251k
        : DI(DI), Ctx(Ctx) {}
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    /// Determine whether this type can be represented in DWARF.
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    static bool CanRepresent(const Type *Ty) {
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563k
      return !Ty->isDependentType() && 
!Ty->isUndeducedType()345k
;
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    }
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    bool VisitImportDecl(ImportDecl *D) {
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      if (!D->getImportedOwningModule())
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        DI.EmitImportDecl(*D);
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      return true;
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    }
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    bool VisitTypeDecl(TypeDecl *D) {
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      // TagDecls may be deferred until after all decls have been merged and we
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      // know the complete type. Pure forward declarations will be skipped, but
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      // they don't need to be emitted into the module anyway.
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      if (auto *TD = dyn_cast<TagDecl>(D))
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        if (!TD->isCompleteDefinition())
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          return true;
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      QualType QualTy = Ctx.getTypeDeclType(D);
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      if (!QualTy.isNull() && CanRepresent(QualTy.getTypePtr()))
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        DI.getOrCreateStandaloneType(QualTy, D->getLocation());
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      return true;
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    }
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    bool VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
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      QualType QualTy(D->getTypeForDecl(), 0);
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      if (!QualTy.isNull() && CanRepresent(QualTy.getTypePtr()))
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        DI.getOrCreateStandaloneType(QualTy, D->getLocation());
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      return true;
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    }
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    bool VisitFunctionDecl(FunctionDecl *D) {
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      if (isa<CXXMethodDecl>(D))
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        // This is not yet supported. Constructing the `this' argument
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        // mandates a CodeGenFunction.
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        return true;
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      SmallVector<QualType, 16> ArgTypes;
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      for (auto i : D->parameters())
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        ArgTypes.push_back(i->getType());
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      QualType RetTy = D->getReturnType();
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      QualType FnTy = Ctx.getFunctionType(RetTy, ArgTypes,
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                                          FunctionProtoType::ExtProtoInfo());
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      if (CanRepresent(FnTy.getTypePtr()))
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        DI.EmitFunctionDecl(D, D->getLocation(), FnTy);
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      return true;
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    }
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    bool VisitObjCMethodDecl(ObjCMethodDecl *D) {
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      if (!D->getClassInterface())
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        return true;
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      bool selfIsPseudoStrong, selfIsConsumed;
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      SmallVector<QualType, 16> ArgTypes;
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      ArgTypes.push_back(D->getSelfType(Ctx, D->getClassInterface(),
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                                        selfIsPseudoStrong, selfIsConsumed));
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      ArgTypes.push_back(Ctx.getObjCSelType());
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      for (auto i : D->parameters())
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        ArgTypes.push_back(i->getType());
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      QualType RetTy = D->getReturnType();
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      QualType FnTy = Ctx.getFunctionType(RetTy, ArgTypes,
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                                          FunctionProtoType::ExtProtoInfo());
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      if (CanRepresent(FnTy.getTypePtr()))
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        DI.EmitFunctionDecl(D, D->getLocation(), FnTy);
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      return true;
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    }
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  };
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public:
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  PCHContainerGenerator(CompilerInstance &CI, const std::string &MainFileName,
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                        const std::string &OutputFileName,
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                        std::unique_ptr<raw_pwrite_stream> OS,
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                        std::shared_ptr<PCHBuffer> Buffer)
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      : Diags(CI.getDiagnostics()), MainFileName(MainFileName),
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        OutputFileName(OutputFileName), Ctx(nullptr),
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        MMap(CI.getPreprocessor().getHeaderSearchInfo().getModuleMap()),
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        HeaderSearchOpts(CI.getHeaderSearchOpts()),
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        PreprocessorOpts(CI.getPreprocessorOpts()),
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        TargetOpts(CI.getTargetOpts()), LangOpts(CI.getLangOpts()),
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        OS(std::move(OS)), Buffer(std::move(Buffer)) {
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    // The debug info output isn't affected by CodeModel and
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    // ThreadModel, but the backend expects them to be nonempty.
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    CodeGenOpts.CodeModel = "default";
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    CodeGenOpts.ThreadModel = "single";
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    CodeGenOpts.DebugTypeExtRefs = true;
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    // When building a module MainFileName is the name of the modulemap file.
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    CodeGenOpts.MainFileName =
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        LangOpts.CurrentModule.empty() ? 
MainFileName10
: LangOpts.CurrentModule;
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    CodeGenOpts.setDebugInfo(codegenoptions::FullDebugInfo);
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    CodeGenOpts.setDebuggerTuning(CI.getCodeGenOpts().getDebuggerTuning());
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    CodeGenOpts.DebugPrefixMap =
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        CI.getInvocation().getCodeGenOpts().DebugPrefixMap;
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  }
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  ~PCHContainerGenerator() override = default;
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  void Initialize(ASTContext &Context) override {
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    assert(!Ctx && "initialized multiple times");
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    Ctx = &Context;
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    VMContext.reset(new llvm::LLVMContext());
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    M.reset(new llvm::Module(MainFileName, *VMContext));
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    M->setDataLayout(Ctx->getTargetInfo().getDataLayout());
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    Builder.reset(new CodeGen::CodeGenModule(
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        *Ctx, HeaderSearchOpts, PreprocessorOpts, CodeGenOpts, *M, Diags));
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    // Prepare CGDebugInfo to emit debug info for a clang module.
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    auto *DI = Builder->getModuleDebugInfo();
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    StringRef ModuleName = llvm::sys::path::filename(MainFileName);
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    DI->setPCHDescriptor(
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        {ModuleName, "", OutputFileName, ASTFileSignature::createDISentinel()});
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    DI->setModuleMap(MMap);
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  }
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  bool HandleTopLevelDecl(DeclGroupRef D) override {
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    if (Diags.hasErrorOccurred())
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      return true;
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    // Collect debug info for all decls in this group.
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    for (auto *I : D)
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      if (!I->isFromASTFile()) {
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        DebugTypeVisitor DTV(*Builder->getModuleDebugInfo(), *Ctx);
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        DTV.TraverseDecl(I);
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      }
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    return true;
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  }
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  void HandleTopLevelDeclInObjCContainer(DeclGroupRef D) override {
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    HandleTopLevelDecl(D);
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  }
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100k
  void HandleTagDeclDefinition(TagDecl *D) override {
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    if (Diags.hasErrorOccurred())
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0
      return;
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100k
    if (D->isFromASTFile())
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1
      return;
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    // Anonymous tag decls are deferred until we are building their declcontext.
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    if (D->getName().empty())
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      return;
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    // Defer tag decls until their declcontext is complete.
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    auto *DeclCtx = D->getDeclContext();
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    while (DeclCtx) {
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      if (auto *D = dyn_cast<TagDecl>(DeclCtx))
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        if (!D->isCompleteDefinition())
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          return;
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      DeclCtx = DeclCtx->getParent();
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    }
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    DebugTypeVisitor DTV(*Builder->getModuleDebugInfo(), *Ctx);
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    DTV.TraverseDecl(D);
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    Builder->UpdateCompletedType(D);
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  }
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  void HandleTagDeclRequiredDefinition(const TagDecl *D) override {
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    if (Diags.hasErrorOccurred())
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      return;
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    if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
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      Builder->getModuleDebugInfo()->completeRequiredType(RD);
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  }
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  void HandleImplicitImportDecl(ImportDecl *D) override {
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    if (!D->getImportedOwningModule())
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      Builder->getModuleDebugInfo()->EmitImportDecl(*D);
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  }
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  /// Emit a container holding the serialized AST.
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  void HandleTranslationUnit(ASTContext &Ctx) override {
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    assert(M && VMContext && Builder);
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    // Delete these on function exit.
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    std::unique_ptr<llvm::LLVMContext> VMContext = std::move(this->VMContext);
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    std::unique_ptr<llvm::Module> M = std::move(this->M);
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    std::unique_ptr<CodeGen::CodeGenModule> Builder = std::move(this->Builder);
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    if (Diags.hasErrorOccurred())
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      return;
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    M->setTargetTriple(Ctx.getTargetInfo().getTriple().getTriple());
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    M->setDataLayout(Ctx.getTargetInfo().getDataLayout());
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    // PCH files don't have a signature field in the control block,
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    // but LLVM detects DWO CUs by looking for a non-zero DWO id.
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    // We use the lower 64 bits for debug info.
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    uint64_t Signature =
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        Buffer->Signature ? Buffer->Signature.truncatedValue() : 
~1ULL10
;
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    Builder->getModuleDebugInfo()->setDwoId(Signature);
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    // Finalize the Builder.
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    if (Builder)
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      Builder->Release();
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    // Ensure the target exists.
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    std::string Error;
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    auto Triple = Ctx.getTargetInfo().getTriple();
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    if (!llvm::TargetRegistry::lookupTarget(Triple.getTriple(), Error))
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      llvm::report_fatal_error(Error);
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    // Emit the serialized Clang AST into its own section.
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    assert(Buffer->IsComplete && "serialization did not complete");
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    auto &SerializedAST = Buffer->Data;
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    auto Size = SerializedAST.size();
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    auto Int8Ty = llvm::Type::getInt8Ty(*VMContext);
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    auto *Ty = llvm::ArrayType::get(Int8Ty, Size);
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    auto *Data = llvm::ConstantDataArray::getString(
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        *VMContext, StringRef(SerializedAST.data(), Size),
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        /*AddNull=*/false);
278
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    auto *ASTSym = new llvm::GlobalVariable(
279
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        *M, Ty, /*constant*/ true, llvm::GlobalVariable::InternalLinkage, Data,
280
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        "__clang_ast");
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    // The on-disk hashtable needs to be aligned.
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    ASTSym->setAlignment(llvm::Align(8));
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    // Mach-O also needs a segment name.
285
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    if (Triple.isOSBinFormatMachO())
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      ASTSym->setSection("__CLANG,__clangast");
287
    // COFF has an eight character length limit.
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4
    else if (Triple.isOSBinFormatCOFF())
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2
      ASTSym->setSection("clangast");
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2
    else
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2
      ASTSym->setSection("__clangast");
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293
299
    LLVM_DEBUG({
294
      // Print the IR for the PCH container to the debug output.
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      llvm::SmallString<0> Buffer;
296
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      clang::EmitBackendOutput(
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          Diags, HeaderSearchOpts, CodeGenOpts, TargetOpts, LangOpts,
298
299
          Ctx.getTargetInfo().getDataLayout(), M.get(),
299
299
          BackendAction::Backend_EmitLL,
300
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          std::make_unique<llvm::raw_svector_ostream>(Buffer));
301
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      llvm::dbgs() << Buffer;
302
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    });
303
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    // Use the LLVM backend to emit the pch container.
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299
    clang::EmitBackendOutput(Diags, HeaderSearchOpts, CodeGenOpts, TargetOpts,
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                             LangOpts, Ctx.getTargetInfo().getDataLayout(),
307
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                             M.get(), BackendAction::Backend_EmitObj,
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                             std::move(OS));
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    // Free the memory for the temporary buffer.
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    llvm::SmallVector<char, 0> Empty;
312
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    SerializedAST = std::move(Empty);
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  }
314
};
315
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} // anonymous namespace
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std::unique_ptr<ASTConsumer>
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ObjectFilePCHContainerWriter::CreatePCHContainerGenerator(
320
    CompilerInstance &CI, const std::string &MainFileName,
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    const std::string &OutputFileName,
322
    std::unique_ptr<llvm::raw_pwrite_stream> OS,
323
299
    std::shared_ptr<PCHBuffer> Buffer) const {
324
299
  return std::make_unique<PCHContainerGenerator>(
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      CI, MainFileName, OutputFileName, std::move(OS), Buffer);
326
299
}
327
328
StringRef
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21.8k
ObjectFilePCHContainerReader::ExtractPCH(llvm::MemoryBufferRef Buffer) const {
330
21.8k
  StringRef PCH;
331
21.8k
  auto OFOrErr = llvm::object::ObjectFile::createObjectFile(Buffer);
332
21.8k
  if (OFOrErr) {
333
19.1k
    auto &OF = OFOrErr.get();
334
19.1k
    bool IsCOFF = isa<llvm::object::COFFObjectFile>(*OF);
335
    // Find the clang AST section in the container.
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38.3k
    for (auto &Section : OF->sections()) {
337
38.3k
      StringRef Name;
338
38.3k
      if (Expected<StringRef> NameOrErr = Section.getName())
339
38.3k
        Name = *NameOrErr;
340
0
      else
341
0
        consumeError(NameOrErr.takeError());
342
343
38.3k
      if ((!IsCOFF && 
Name == "__clangast"38.3k
) ||
(19.1k
IsCOFF19.1k
&&
Name == "clangast"8
)) {
344
19.1k
        if (Expected<StringRef> E = Section.getContents())
345
19.1k
          return *E;
346
0
        else {
347
0
          handleAllErrors(E.takeError(), [&](const llvm::ErrorInfoBase &EIB) {
348
0
            EIB.log(llvm::errs());
349
0
          });
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0
          return "";
351
0
        }
352
19.1k
      }
353
38.3k
    }
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19.1k
  }
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2.70k
  handleAllErrors(OFOrErr.takeError(), [&](const llvm::ErrorInfoBase &EIB) {
356
2.70k
    if (EIB.convertToErrorCode() ==
357
2.70k
        llvm::object::object_error::invalid_file_type)
358
      // As a fallback, treat the buffer as a raw AST.
359
2.70k
      PCH = Buffer.getBuffer();
360
0
    else
361
0
      EIB.log(llvm::errs());
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2.70k
  });
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2.70k
  return PCH;
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21.8k
}