CodeGenModule.cpp

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//===--- CodeGenModule.cpp - Emit LLVM Code from ASTs for a Module --------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This coordinates the per-module state used while generating code.
//
//===----------------------------------------------------------------------===//
 
#include "CodeGenModule.h"
#include "ABIInfo.h"
#include "CGBlocks.h"
#include "CGCUDARuntime.h"
#include "CGCXXABI.h"
#include "CGCall.h"
#include "CGDebugInfo.h"
#include "CGHLSLRuntime.h"
#include "CGObjCRuntime.h"
#include "CGOpenCLRuntime.h"
#include "CGOpenMPRuntime.h"
#include "CGOpenMPRuntimeGPU.h"
#include "CodeGenFunction.h"
#include "CodeGenPGO.h"
#include "ConstantEmitter.h"
#include "CoverageMappingGen.h"
#include "TargetInfo.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/Mangle.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/Basic/Builtins.h"
#include "clang/Basic/CharInfo.h"
#include "clang/Basic/CodeGenOptions.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/Module.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Basic/Version.h"
#include "clang/CodeGen/BackendUtil.h"
#include "clang/CodeGen/ConstantInitBuilder.h"
#include "clang/Frontend/FrontendDiagnostic.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Frontend/OpenMP/OMPIRBuilder.h"
#include "llvm/IR/AttributeMask.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/ProfileSummary.h"
#include "llvm/ProfileData/InstrProfReader.h"
#include "llvm/ProfileData/SampleProf.h"
#include "llvm/Support/CRC.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ConvertUTF.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TimeProfiler.h"
#include "llvm/Support/xxhash.h"
#include "llvm/TargetParser/Triple.h"
#include "llvm/TargetParser/X86TargetParser.h"
#include <optional>
 
using namespace clang;
using namespace CodeGen;
 
static llvm::cl::opt<bool> LimitedCoverage(
    "limited-coverage-experimental", llvm::cl::Hidden,
    llvm::cl::desc("Emit limited coverage mapping information (experimental)"));
 
static const char AnnotationSection[] = "llvm.metadata";
 
static CGCXXABI *createCXXABI(CodeGenModule &CGM) {
  switch (CGM.getContext().getCXXABIKind()) {
  case TargetCXXABI::AppleARM64:
  case TargetCXXABI::Fuchsia:
  case TargetCXXABI::GenericAArch64:
  case TargetCXXABI::GenericARM:
  case TargetCXXABI::iOS:
  case TargetCXXABI::WatchOS:
  case TargetCXXABI::GenericMIPS:
  case TargetCXXABI::GenericItanium:
  case TargetCXXABI::WebAssembly:
  case TargetCXXABI::XL:
    return CreateItaniumCXXABI(CGM);
  case TargetCXXABI::Microsoft:
    return CreateMicrosoftCXXABI(CGM);
  }
 
  llvm_unreachable("invalid C++ ABI kind");
}
 
static std::unique_ptr<TargetCodeGenInfo>
createTargetCodeGenInfo(CodeGenModule &CGM) {
  const TargetInfo &Target = CGM.getTarget();
  const llvm::Triple &Triple = Target.getTriple();
  const CodeGenOptions &CodeGenOpts = CGM.getCodeGenOpts();
 
  switch (Triple.getArch()) {
  default:
    return createDefaultTargetCodeGenInfo(CGM);
 
  case llvm::Triple::le32:
    return createPNaClTargetCodeGenInfo(CGM);
  case llvm::Triple::m68k:
    return createM68kTargetCodeGenInfo(CGM);
  case llvm::Triple::mips:
  case llvm::Triple::mipsel:
    if (Triple.getOS() == llvm::Triple::NaCl)
      return createPNaClTargetCodeGenInfo(CGM);
    return createMIPSTargetCodeGenInfo(CGM, /*IsOS32=*/true);
 
  case llvm::Triple::mips64:
  case llvm::Triple::mips64el:
    return createMIPSTargetCodeGenInfo(CGM, /*IsOS32=*/false);
 
  case llvm::Triple::avr: {
    // For passing parameters, R8~R25 are used on avr, and R18~R25 are used
    // on avrtiny. For passing return value, R18~R25 are used on avr, and
    // R22~R25 are used on avrtiny.
    unsigned NPR = Target.getABI() == "avrtiny" ? 6 : 18;
    unsigned NRR = Target.getABI() == "avrtiny" ? 4 : 8;
    return createAVRTargetCodeGenInfo(CGM, NPR, NRR);
  }
 
  case llvm::Triple::aarch64:
  case llvm::Triple::aarch64_32:
  case llvm::Triple::aarch64_be: {
    AArch64ABIKind Kind = AArch64ABIKind::AAPCS;
    if (Target.getABI() == "darwinpcs")
      Kind = AArch64ABIKind::DarwinPCS;
    else if (Triple.isOSWindows())
      return createWindowsAArch64TargetCodeGenInfo(CGM, AArch64ABIKind::Win64);
 
    return createAArch64TargetCodeGenInfo(CGM, Kind);
  }
 
  case llvm::Triple::wasm32:
  case llvm::Triple::wasm64: {
    WebAssemblyABIKind Kind = WebAssemblyABIKind::MVP;
    if (Target.getABI() == "experimental-mv")
      Kind = WebAssemblyABIKind::ExperimentalMV;
    return createWebAssemblyTargetCodeGenInfo(CGM, Kind);
  }
 
  case llvm::Triple::arm:
  case llvm::Triple::armeb:
  case llvm::Triple::thumb:
  case llvm::Triple::thumbeb: {
    if (Triple.getOS() == llvm::Triple::Win32)
      return createWindowsARMTargetCodeGenInfo(CGM, ARMABIKind::AAPCS_VFP);
 
    ARMABIKind Kind = ARMABIKind::AAPCS;
    StringRef ABIStr = Target.getABI();
    if (ABIStr == "apcs-gnu")
      Kind = ARMABIKind::APCS;
    else if (ABIStr == "aapcs16")
      Kind = ARMABIKind::AAPCS16_VFP;
    else if (CodeGenOpts.FloatABI == "hard" ||
             (CodeGenOpts.FloatABI != "soft" &&
              (Triple.getEnvironment() == llvm::Triple::GNUEABIHF ||
               Triple.getEnvironment() == llvm::Triple::MuslEABIHF ||
               Triple.getEnvironment() == llvm::Triple::EABIHF)))
      Kind = ARMABIKind::AAPCS_VFP;
 
    return createARMTargetCodeGenInfo(CGM, Kind);
  }
 
  case llvm::Triple::ppc: {
    if (Triple.isOSAIX())
      return createAIXTargetCodeGenInfo(CGM, /*Is64Bit=*/false);
 
    bool IsSoftFloat =
        CodeGenOpts.FloatABI == "soft" || Target.hasFeature("spe");
    return createPPC32TargetCodeGenInfo(CGM, IsSoftFloat);
  }
  case llvm::Triple::ppcle: {
    bool IsSoftFloat = CodeGenOpts.FloatABI == "soft";
    return createPPC32TargetCodeGenInfo(CGM, IsSoftFloat);
  }
  case llvm::Triple::ppc64:
    if (Triple.isOSAIX())
      return createAIXTargetCodeGenInfo(CGM, /*Is64Bit=*/true);
 
    if (Triple.isOSBinFormatELF()) {
      PPC64_SVR4_ABIKind Kind = PPC64_SVR4_ABIKind::ELFv1;
      if (Target.getABI() == "elfv2")
        Kind = PPC64_SVR4_ABIKind::ELFv2;
      bool IsSoftFloat = CodeGenOpts.FloatABI == "soft";
 
      return createPPC64_SVR4_TargetCodeGenInfo(CGM, Kind, IsSoftFloat);
    }
    return createPPC64TargetCodeGenInfo(CGM);
  case llvm::Triple::ppc64le: {
    assert(Triple.isOSBinFormatELF() && "PPC64 LE non-ELF not supported!");
    PPC64_SVR4_ABIKind Kind = PPC64_SVR4_ABIKind::ELFv2;
    if (Target.getABI() == "elfv1")
      Kind = PPC64_SVR4_ABIKind::ELFv1;
    bool IsSoftFloat = CodeGenOpts.FloatABI == "soft";
 
    return createPPC64_SVR4_TargetCodeGenInfo(CGM, Kind, IsSoftFloat);
  }
 
  case llvm::Triple::nvptx:
  case llvm::Triple::nvptx64:
    return createNVPTXTargetCodeGenInfo(CGM);
 
  case llvm::Triple::msp430:
    return createMSP430TargetCodeGenInfo(CGM);
 
  case llvm::Triple::riscv32:
  case llvm::Triple::riscv64: {
    StringRef ABIStr = Target.getABI();
    unsigned XLen = Target.getPointerWidth(LangAS::Default);
    unsigned ABIFLen = 0;
    if (ABIStr.endswith("f"))
      ABIFLen = 32;
    else if (ABIStr.endswith("d"))
      ABIFLen = 64;
    return createRISCVTargetCodeGenInfo(CGM, XLen, ABIFLen);
  }
 
  case llvm::Triple::systemz: {
    bool SoftFloat = CodeGenOpts.FloatABI == "soft";
    bool HasVector = !SoftFloat && Target.getABI() == "vector";
    return createSystemZTargetCodeGenInfo(CGM, HasVector, SoftFloat);
  }
 
  case llvm::Triple::tce:
  case llvm::Triple::tcele:
    return createTCETargetCodeGenInfo(CGM);
 
  case llvm::Triple::x86: {
    bool IsDarwinVectorABI = Triple.isOSDarwin();
    bool IsWin32FloatStructABI = Triple.isOSWindows() && !Triple.isOSCygMing();
 
    if (Triple.getOS() == llvm::Triple::Win32) {
      return createWinX86_32TargetCodeGenInfo(
          CGM, IsDarwinVectorABI, IsWin32FloatStructABI,
          CodeGenOpts.NumRegisterParameters);
    }
    return createX86_32TargetCodeGenInfo(
        CGM, IsDarwinVectorABI, IsWin32FloatStructABI,
        CodeGenOpts.NumRegisterParameters, CodeGenOpts.FloatABI == "soft");
  }
 
  case llvm::Triple::x86_64: {
    StringRef ABI = Target.getABI();
    X86AVXABILevel AVXLevel = (ABI == "avx512" ? X86AVXABILevel::AVX512
                               : ABI == "avx"  ? X86AVXABILevel::AVX
                                               : X86AVXABILevel::None);
 
    switch (Triple.getOS()) {
    case llvm::Triple::Win32:
      return createWinX86_64TargetCodeGenInfo(CGM, AVXLevel);
    default:
      return createX86_64TargetCodeGenInfo(CGM, AVXLevel);
    }
  }
  case llvm::Triple::hexagon:
    return createHexagonTargetCodeGenInfo(CGM);
  case llvm::Triple::lanai:
    return createLanaiTargetCodeGenInfo(CGM);
  case llvm::Triple::r600:
    return createAMDGPUTargetCodeGenInfo(CGM);
  case llvm::Triple::amdgcn:
    return createAMDGPUTargetCodeGenInfo(CGM);
  case llvm::Triple::sparc:
    return createSparcV8TargetCodeGenInfo(CGM);
  case llvm::Triple::sparcv9:
    return createSparcV9TargetCodeGenInfo(CGM);
  case llvm::Triple::xcore:
    return createXCoreTargetCodeGenInfo(CGM);
  case llvm::Triple::arc:
    return createARCTargetCodeGenInfo(CGM);
  case llvm::Triple::spir:
  case llvm::Triple::spir64:
    return createCommonSPIRTargetCodeGenInfo(CGM);
  case llvm::Triple::spirv32:
  case llvm::Triple::spirv64:
    return createSPIRVTargetCodeGenInfo(CGM);
  case llvm::Triple::ve:
    return createVETargetCodeGenInfo(CGM);
  case llvm::Triple::csky: {
    bool IsSoftFloat = !Target.hasFeature("hard-float-abi");
    bool hasFP64 =
        Target.hasFeature("fpuv2_df") || Target.hasFeature("fpuv3_df");
    return createCSKYTargetCodeGenInfo(CGM, IsSoftFloat ? 0
                                            : hasFP64   ? 64
                                                        : 32);
  }
  case llvm::Triple::bpfeb:
  case llvm::Triple::bpfel:
    return createBPFTargetCodeGenInfo(CGM);
  case llvm::Triple::loongarch32:
  case llvm::Triple::loongarch64: {
    StringRef ABIStr = Target.getABI();
    unsigned ABIFRLen = 0;
    if (ABIStr.endswith("f"))
      ABIFRLen = 32;
    else if (ABIStr.endswith("d"))
      ABIFRLen = 64;
    return createLoongArchTargetCodeGenInfo(
        CGM, Target.getPointerWidth(LangAS::Default), ABIFRLen);
  }
  }
}
 
const TargetCodeGenInfo &CodeGenModule::getTargetCodeGenInfo() {
  if (!TheTargetCodeGenInfo)
    TheTargetCodeGenInfo = createTargetCodeGenInfo(*this);
  return *TheTargetCodeGenInfo;
}
 
CodeGenModule::CodeGenModule(ASTContext &C,
                             IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS,
                             const HeaderSearchOptions &HSO,
                             const PreprocessorOptions &PPO,
                             const CodeGenOptions &CGO, llvm::Module &M,
                             DiagnosticsEngine &diags,
                             CoverageSourceInfo *CoverageInfo)
    : Context(C), LangOpts(C.getLangOpts()), FS(FS), HeaderSearchOpts(HSO),
      PreprocessorOpts(PPO), CodeGenOpts(CGO), TheModule(M), Diags(diags),
      Target(C.getTargetInfo()), ABI(createCXXABI(*this)),
      VMContext(M.getContext()), Types(*this), VTables(*this),
      SanitizerMD(new SanitizerMetadata(*this)) {
 
  // Initialize the type cache.
  llvm::LLVMContext &LLVMContext = M.getContext();
  VoidTy = llvm::Type::getVoidTy(LLVMContext);
  Int8Ty = llvm::Type::getInt8Ty(LLVMContext);
  Int16Ty = llvm::Type::getInt16Ty(LLVMContext);
  Int32Ty = llvm::Type::getInt32Ty(LLVMContext);
  Int64Ty = llvm::Type::getInt64Ty(LLVMContext);
  HalfTy = llvm::Type::getHalfTy(LLVMContext);
  BFloatTy = llvm::Type::getBFloatTy(LLVMContext);
  FloatTy = llvm::Type::getFloatTy(LLVMContext);
  DoubleTy = llvm::Type::getDoubleTy(LLVMContext);
  PointerWidthInBits = C.getTargetInfo().getPointerWidth(LangAS::Default);
  PointerAlignInBytes =
      C.toCharUnitsFromBits(C.getTargetInfo().getPointerAlign(LangAS::Default))
          .getQuantity();
  SizeSizeInBytes =
    C.toCharUnitsFromBits(C.getTargetInfo().getMaxPointerWidth()).getQuantity();
  IntAlignInBytes =
    C.toCharUnitsFromBits(C.getTargetInfo().getIntAlign()).getQuantity();
  CharTy =
    llvm::IntegerType::get(LLVMContext, C.getTargetInfo().getCharWidth());
  IntTy = llvm::IntegerType::get(LLVMContext, C.getTargetInfo().getIntWidth());
  IntPtrTy = llvm::IntegerType::get(LLVMContext,
    C.getTargetInfo().getMaxPointerWidth());
  Int8PtrTy = llvm::PointerType::get(LLVMContext, 0);
  const llvm::DataLayout &DL = M.getDataLayout();
  AllocaInt8PtrTy =
      llvm::PointerType::get(LLVMContext, DL.getAllocaAddrSpace());
  GlobalsInt8PtrTy =
      llvm::PointerType::get(LLVMContext, DL.getDefaultGlobalsAddressSpace());
  ConstGlobalsPtrTy = llvm::PointerType::get(
      LLVMContext, C.getTargetAddressSpace(GetGlobalConstantAddressSpace()));
  ASTAllocaAddressSpace = getTargetCodeGenInfo().getASTAllocaAddressSpace();
 
  // Build C++20 Module initializers.
  // TODO: Add Microsoft here once we know the mangling required for the
  // initializers.
  CXX20ModuleInits =
      LangOpts.CPlusPlusModules && getCXXABI().getMangleContext().getKind() ==
                                       ItaniumMangleContext::MK_Itanium;
 
  RuntimeCC = getTargetCodeGenInfo().getABIInfo().getRuntimeCC();
 
  if (LangOpts.ObjC)
    createObjCRuntime();
  if (LangOpts.OpenCL)
    createOpenCLRuntime();
  if (LangOpts.OpenMP)
    createOpenMPRuntime();
  if (LangOpts.CUDA)
    createCUDARuntime();
  if (LangOpts.HLSL)
    createHLSLRuntime();
 
  // Enable TBAA unless it's suppressed. ThreadSanitizer needs TBAA even at O0.
  if (LangOpts.Sanitize.has(SanitizerKind::Thread) ||
      (!CodeGenOpts.RelaxedAliasing && CodeGenOpts.OptimizationLevel > 0))
    TBAA.reset(new CodeGenTBAA(Context, TheModule, CodeGenOpts, getLangOpts(),
                               getCXXABI().getMangleContext()));
 
  // If debug info or coverage generation is enabled, create the CGDebugInfo
  // object.
  if (CodeGenOpts.getDebugInfo() != llvm::codegenoptions::NoDebugInfo ||
      CodeGenOpts.CoverageNotesFile.size() ||
      CodeGenOpts.CoverageDataFile.size())
    DebugInfo.reset(new CGDebugInfo(*this));
 
  Block.GlobalUniqueCount = 0;
 
  if (C.getLangOpts().ObjC)
    ObjCData.reset(new ObjCEntrypoints());
 
  if (CodeGenOpts.hasProfileClangUse()) {
    auto ReaderOrErr = llvm::IndexedInstrProfReader::create(
        CodeGenOpts.ProfileInstrumentUsePath, *FS,
        CodeGenOpts.ProfileRemappingFile);
    // We're checking for profile read errors in CompilerInvocation, so if
    // there was an error it should've already been caught. If it hasn't been
    // somehow, trip an assertion.
    assert(ReaderOrErr);
    PGOReader = std::move(ReaderOrErr.get());
  }
 
  // If coverage mapping generation is enabled, create the
  // CoverageMappingModuleGen object.
  if (CodeGenOpts.CoverageMapping)
    CoverageMapping.reset(new CoverageMappingModuleGen(*this, *CoverageInfo));
 
  // Generate the module name hash here if needed.
  if (CodeGenOpts.UniqueInternalLinkageNames &&
      !getModule().getSourceFileName().empty()) {
    std::string Path = getModule().getSourceFileName();
    // Check if a path substitution is needed from the MacroPrefixMap.
    for (const auto &Entry : LangOpts.MacroPrefixMap)
      if (Path.rfind(Entry.first, 0) != std::string::npos) {
        Path = Entry.second + Path.substr(Entry.first.size());
        break;
      }
    ModuleNameHash = llvm::getUniqueInternalLinkagePostfix(Path);
  }
}
 
CodeGenModule::~CodeGenModule() {}
 
void CodeGenModule::createObjCRuntime() {
  // This is just isGNUFamily(), but we want to force implementors of
  // new ABIs to decide how best to do this.
  switch (LangOpts.ObjCRuntime.getKind()) {
  case ObjCRuntime::GNUstep:
  case ObjCRuntime::GCC:
  case ObjCRuntime::ObjFW:
    ObjCRuntime.reset(CreateGNUObjCRuntime(*this));
    return;
 
  case ObjCRuntime::FragileMacOSX:
  case ObjCRuntime::MacOSX:
  case ObjCRuntime::iOS:
  case ObjCRuntime::WatchOS:
    ObjCRuntime.reset(CreateMacObjCRuntime(*this));
    return;
  }
  llvm_unreachable("bad runtime kind");
}
 
void CodeGenModule::createOpenCLRuntime() {
  OpenCLRuntime.reset(new CGOpenCLRuntime(*this));
}
 
void CodeGenModule::createOpenMPRuntime() {
  // Select a specialized code generation class based on the target, if any.
  // If it does not exist use the default implementation.
  switch (getTriple().getArch()) {
  case llvm::Triple::nvptx:
  case llvm::Triple::nvptx64:
  case llvm::Triple::amdgcn:
    assert(getLangOpts().OpenMPIsTargetDevice &&
           "OpenMP AMDGPU/NVPTX is only prepared to deal with device code.");
    OpenMPRuntime.reset(new CGOpenMPRuntimeGPU(*this));
    break;
  default:
    if (LangOpts.OpenMPSimd)
      OpenMPRuntime.reset(new CGOpenMPSIMDRuntime(*this));
    else
      OpenMPRuntime.reset(new CGOpenMPRuntime(*this));
    break;
  }
}
 
void CodeGenModule::createCUDARuntime() {
  CUDARuntime.reset(CreateNVCUDARuntime(*this));
}
 
void CodeGenModule::createHLSLRuntime() {
  HLSLRuntime.reset(new CGHLSLRuntime(*this));
}
 
void CodeGenModule::addReplacement(StringRef Name, llvm::Constant *C) {
  Replacements[Name] = C;
}
 
void CodeGenModule::applyReplacements() {
  for (auto &I : Replacements) {
    StringRef MangledName = I.first;
    llvm::Constant *Replacement = I.second;
    llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
    if (!Entry)
      continue;
    auto *OldF = cast<llvm::Function>(Entry);
    auto *NewF = dyn_cast<llvm::Function>(Replacement);
    if (!NewF) {
      if (auto *Alias = dyn_cast<llvm::GlobalAlias>(Replacement)) {
        NewF = dyn_cast<llvm::Function>(Alias->getAliasee());
      } else {
        auto *CE = cast<llvm::ConstantExpr>(Replacement);
        assert(CE->getOpcode() == llvm::Instruction::BitCast ||
               CE->getOpcode() == llvm::Instruction::GetElementPtr);
        NewF = dyn_cast<llvm::Function>(CE->getOperand(0));
      }
    }
 
    // Replace old with new, but keep the old order.
    OldF->replaceAllUsesWith(Replacement);
    if (NewF) {
      NewF->removeFromParent();
      OldF->getParent()->getFunctionList().insertAfter(OldF->getIterator(),
                                                       NewF);
    }
    OldF->eraseFromParent();
  }
}
 
void CodeGenModule::addGlobalValReplacement(llvm::GlobalValue *GV, llvm::Constant *C) {
  GlobalValReplacements.push_back(std::make_pair(GV, C));
}
 
void CodeGenModule::applyGlobalValReplacements() {
  for (auto &I : GlobalValReplacements) {
    llvm::GlobalValue *GV = I.first;
    llvm::Constant *C = I.second;
 
    GV->replaceAllUsesWith(C);
    GV->eraseFromParent();
  }
}
 
// This is only used in aliases that we created and we know they have a
// linear structure.
static const llvm::GlobalValue *getAliasedGlobal(const llvm::GlobalValue *GV) {
  const llvm::Constant *C;
  if (auto *GA = dyn_cast<llvm::GlobalAlias>(GV))
    C = GA->getAliasee();
  else if (auto *GI = dyn_cast<llvm::GlobalIFunc>(GV))
    C = GI->getResolver();
  else
    return GV;
 
  const auto *AliaseeGV = dyn_cast<llvm::GlobalValue>(C->stripPointerCasts());
  if (!AliaseeGV)
    return nullptr;
 
  const llvm::GlobalValue *FinalGV = AliaseeGV->getAliaseeObject();
  if (FinalGV == GV)
    return nullptr;
 
  return FinalGV;
}
 
static bool checkAliasedGlobal(
    const ASTContext &Context, DiagnosticsEngine &Diags, SourceLocation Location,
    bool IsIFunc, const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
    const llvm::MapVector<GlobalDecl, StringRef> &MangledDeclNames,
    SourceRange AliasRange) {
  GV = getAliasedGlobal(Alias);
  if (!GV) {
    Diags.Report(Location, diag::err_cyclic_alias) << IsIFunc;
    return false;
  }
 
  if (GV->hasCommonLinkage()) {
    const llvm::Triple &Triple = Context.getTargetInfo().getTriple();
    if (Triple.getObjectFormat() == llvm::Triple::XCOFF) {
      Diags.Report(Location, diag::err_alias_to_common);
      return false;
    }
  }
 
  if (GV->isDeclaration()) {
    Diags.Report(Location, diag::err_alias_to_undefined) << IsIFunc << IsIFunc;
    Diags.Report(Location, diag::note_alias_requires_mangled_name)
        << IsIFunc << IsIFunc;
    // Provide a note if the given function is not found and exists as a
    // mangled name.
    for (const auto &[Decl, Name] : MangledDeclNames) {
      if (const auto *ND = dyn_cast<NamedDecl>(Decl.getDecl())) {
        if (ND->getName() == GV->getName()) {
          Diags.Report(Location, diag::note_alias_mangled_name_alternative)
              << Name
              << FixItHint::CreateReplacement(
                     AliasRange,
                     (Twine(IsIFunc ? "ifunc" : "alias") + "(\"" + Name + "\")")
                         .str());
        }
      }
    }
    return false;
  }
 
  if (IsIFunc) {
    // Check resolver function type.
    const auto *F = dyn_cast<llvm::Function>(GV);
    if (!F) {
      Diags.Report(Location, diag::err_alias_to_undefined)
          << IsIFunc << IsIFunc;
      return false;
    }
 
    llvm::FunctionType *FTy = F->getFunctionType();
    if (!FTy->getReturnType()->isPointerTy()) {
      Diags.Report(Location, diag::err_ifunc_resolver_return);
      return false;
    }
  }
 
  return true;
}
 
void CodeGenModule::checkAliases() {
  // Check if the constructed aliases are well formed. It is really unfortunate
  // that we have to do this in CodeGen, but we only construct mangled names
  // and aliases during codegen.
  bool Error = false;
  DiagnosticsEngine &Diags = getDiags();
  for (const GlobalDecl &GD : Aliases) {
    const auto *D = cast<ValueDecl>(GD.getDecl());
    SourceLocation Location;
    SourceRange Range;
    bool IsIFunc = D->hasAttr<IFuncAttr>();
    if (const Attr *A = D->getDefiningAttr()) {
      Location = A->getLocation();
      Range = A->getRange();
    } else
      llvm_unreachable("Not an alias or ifunc?");
 
    StringRef MangledName = getMangledName(GD);
    llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
    const llvm::GlobalValue *GV = nullptr;
    if (!checkAliasedGlobal(getContext(), Diags, Location, IsIFunc, Alias, GV,
                            MangledDeclNames, Range)) {
      Error = true;
      continue;
    }
 
    llvm::Constant *Aliasee =
        IsIFunc ? cast<llvm::GlobalIFunc>(Alias)->getResolver()
                : cast<llvm::GlobalAlias>(Alias)->getAliasee();
 
    llvm::GlobalValue *AliaseeGV;
    if (auto CE = dyn_cast<llvm::ConstantExpr>(Aliasee))
      AliaseeGV = cast<llvm::GlobalValue>(CE->getOperand(0));
    else
      AliaseeGV = cast<llvm::GlobalValue>(Aliasee);
 
    if (const SectionAttr *SA = D->getAttr<SectionAttr>()) {
      StringRef AliasSection = SA->getName();
      if (AliasSection != AliaseeGV->getSection())
        Diags.Report(SA->getLocation(), diag::warn_alias_with_section)
            << AliasSection << IsIFunc << IsIFunc;
    }
 
    // We have to handle alias to weak aliases in here. LLVM itself disallows
    // this since the object semantics would not match the IL one. For
    // compatibility with gcc we implement it by just pointing the alias
    // to its aliasee's aliasee. We also warn, since the user is probably
    // expecting the link to be weak.
    if (auto *GA = dyn_cast<llvm::GlobalAlias>(AliaseeGV)) {
      if (GA->isInterposable()) {
        Diags.Report(Location, diag::warn_alias_to_weak_alias)
            << GV->getName() << GA->getName() << IsIFunc;
        Aliasee = llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(
            GA->getAliasee(), Alias->getType());
 
        if (IsIFunc)
          cast<llvm::GlobalIFunc>(Alias)->setResolver(Aliasee);
        else
          cast<llvm::GlobalAlias>(Alias)->setAliasee(Aliasee);
      }
    }
  }
  if (!Error)
    return;
 
  for (const GlobalDecl &GD : Aliases) {
    StringRef MangledName = getMangledName(GD);
    llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
    Alias->replaceAllUsesWith(llvm::UndefValue::get(Alias->getType()));
    Alias->eraseFromParent();
  }
}
 
void CodeGenModule::clear() {
  DeferredDeclsToEmit.clear();
  EmittedDeferredDecls.clear();
  if (OpenMPRuntime)
    OpenMPRuntime->clear();
}
 
void InstrProfStats::reportDiagnostics(DiagnosticsEngine &Diags,
                                       StringRef MainFile) {
  if (!hasDiagnostics())
    return;
  if (VisitedInMainFile > 0 && VisitedInMainFile == MissingInMainFile) {
    if (MainFile.empty())
      MainFile = "<stdin>";
    Diags.Report(diag::warn_profile_data_unprofiled) << MainFile;
  } else {
    if (Mismatched > 0)
      Diags.Report(diag::warn_profile_data_out_of_date) << Visited << Mismatched;
 
    if (Missing > 0)
      Diags.Report(diag::warn_profile_data_missing) << Visited << Missing;
  }
}
 
static void setVisibilityFromDLLStorageClass(const clang::LangOptions &LO,
                                             llvm::Module &M) {
  if (!LO.VisibilityFromDLLStorageClass)
    return;
 
  llvm::GlobalValue::VisibilityTypes DLLExportVisibility =
      CodeGenModule::GetLLVMVisibility(LO.getDLLExportVisibility());
  llvm::GlobalValue::VisibilityTypes NoDLLStorageClassVisibility =
      CodeGenModule::GetLLVMVisibility(LO.getNoDLLStorageClassVisibility());
  llvm::GlobalValue::VisibilityTypes ExternDeclDLLImportVisibility =
      CodeGenModule::GetLLVMVisibility(LO.getExternDeclDLLImportVisibility());
  llvm::GlobalValue::VisibilityTypes ExternDeclNoDLLStorageClassVisibility =
      CodeGenModule::GetLLVMVisibility(
          LO.getExternDeclNoDLLStorageClassVisibility());
 
  for (llvm::GlobalValue &GV : M.global_values()) {
    if (GV.hasAppendingLinkage() || GV.hasLocalLinkage())
      continue;
 
    // Reset DSO locality before setting the visibility. This removes
    // any effects that visibility options and annotations may have
    // had on the DSO locality. Setting the visibility will implicitly set
    // appropriate globals to DSO Local; however, this will be pessimistic
    // w.r.t. to the normal compiler IRGen.
    GV.setDSOLocal(false);
 
    if (GV.isDeclarationForLinker()) {
      GV.setVisibility(GV.getDLLStorageClass() ==
                               llvm::GlobalValue::DLLImportStorageClass
                           ? ExternDeclDLLImportVisibility
                           : ExternDeclNoDLLStorageClassVisibility);
    } else {
      GV.setVisibility(GV.getDLLStorageClass() ==
                               llvm::GlobalValue::DLLExportStorageClass
                           ? DLLExportVisibility
                           : NoDLLStorageClassVisibility);
    }
 
    GV.setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
  }
}
 
void CodeGenModule::Release() {
  Module *Primary = getContext().getCurrentNamedModule();
  if (CXX20ModuleInits && Primary && !Primary->isHeaderLikeModule())
    EmitModuleInitializers(Primary);
  EmitDeferred();
  DeferredDecls.insert(EmittedDeferredDecls.begin(),
                       EmittedDeferredDecls.end());
  EmittedDeferredDecls.clear();
  EmitVTablesOpportunistically();
  applyGlobalValReplacements();
  applyReplacements();
  emitMultiVersionFunctions();
 
  if (Context.getLangOpts().IncrementalExtensions &&
      GlobalTopLevelStmtBlockInFlight.first) {
    const TopLevelStmtDecl *TLSD = GlobalTopLevelStmtBlockInFlight.second;
    GlobalTopLevelStmtBlockInFlight.first->FinishFunction(TLSD->getEndLoc());
    GlobalTopLevelStmtBlockInFlight = {nullptr, nullptr};
  }
 
  // Module implementations are initialized the same way as a regular TU that
  // imports one or more modules.
  if (CXX20ModuleInits && Primary && Primary->isInterfaceOrPartition())
    EmitCXXModuleInitFunc(Primary);
  else
    EmitCXXGlobalInitFunc();
  EmitCXXGlobalCleanUpFunc();
  registerGlobalDtorsWithAtExit();
  EmitCXXThreadLocalInitFunc();
  if (ObjCRuntime)
    if (llvm::Function *ObjCInitFunction = ObjCRuntime->ModuleInitFunction())
      AddGlobalCtor(ObjCInitFunction);
  if (Context.getLangOpts().CUDA && CUDARuntime) {
    if (llvm::Function *CudaCtorFunction = CUDARuntime->finalizeModule())
      AddGlobalCtor(CudaCtorFunction);
  }
  if (OpenMPRuntime) {
    if (llvm::Function *OpenMPRequiresDirectiveRegFun =
            OpenMPRuntime->emitRequiresDirectiveRegFun()) {
      AddGlobalCtor(OpenMPRequiresDirectiveRegFun, 0);
    }
    OpenMPRuntime->createOffloadEntriesAndInfoMetadata();
    OpenMPRuntime->clear();
  }
  if (PGOReader) {
    getModule().setProfileSummary(
        PGOReader->getSummary(/* UseCS */ false).getMD(VMContext),
        llvm::ProfileSummary::PSK_Instr);
    if (PGOStats.hasDiagnostics())
      PGOStats.reportDiagnostics(getDiags(), getCodeGenOpts().MainFileName);
  }
  llvm::stable_sort(GlobalCtors, [](const Structor &L, const Structor &R) {
    return L.LexOrder < R.LexOrder;
  });
  EmitCtorList(GlobalCtors, "llvm.global_ctors");
  EmitCtorList(GlobalDtors, "llvm.global_dtors");
  EmitGlobalAnnotations();
  EmitStaticExternCAliases();
  checkAliases();
  EmitDeferredUnusedCoverageMappings();
  CodeGenPGO(*this).setValueProfilingFlag(getModule());
  if (CoverageMapping)
    CoverageMapping->emit();
  if (CodeGenOpts.SanitizeCfiCrossDso) {
    CodeGenFunction(*this).EmitCfiCheckFail();
    CodeGenFunction(*this).EmitCfiCheckStub();
  }
  if (LangOpts.Sanitize.has(SanitizerKind::KCFI))
    finalizeKCFITypes();
  emitAtAvailableLinkGuard();
  if (Context.getTargetInfo().getTriple().isWasm())
    EmitMainVoidAlias();
 
  if (getTriple().isAMDGPU()) {
    // Emit amdgpu_code_object_version module flag, which is code object version
    // times 100.
    if (getTarget().getTargetOpts().CodeObjectVersion !=
        TargetOptions::COV_None) {
      getModule().addModuleFlag(llvm::Module::Error,
                                "amdgpu_code_object_version",
                                getTarget().getTargetOpts().CodeObjectVersion);
    }
 
    // Currently, "-mprintf-kind" option is only supported for HIP
    if (LangOpts.HIP) {
      auto *MDStr = llvm::MDString::get(
          getLLVMContext(), (getTarget().getTargetOpts().AMDGPUPrintfKindVal ==
                             TargetOptions::AMDGPUPrintfKind::Hostcall)
                                ? "hostcall"
                                : "buffered");
      getModule().addModuleFlag(llvm::Module::Error, "amdgpu_printf_kind",
                                MDStr);
    }
  }
 
  // Emit a global array containing all external kernels or device variables
  // used by host functions and mark it as used for CUDA/HIP. This is necessary
  // to get kernels or device variables in archives linked in even if these
  // kernels or device variables are only used in host functions.
  if (!Context.CUDAExternalDeviceDeclODRUsedByHost.empty()) {
    SmallVector<llvm::Constant *, 8> UsedArray;
    for (auto D : Context.CUDAExternalDeviceDeclODRUsedByHost) {
      GlobalDecl GD;
      if (auto *FD = dyn_cast<FunctionDecl>(D))
        GD = GlobalDecl(FD, KernelReferenceKind::Kernel);
      else
        GD = GlobalDecl(D);
      UsedArray.push_back(llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(
          GetAddrOfGlobal(GD), Int8PtrTy));
    }
 
    llvm::ArrayType *ATy = llvm::ArrayType::get(Int8PtrTy, UsedArray.size());
 
    auto *GV = new llvm::GlobalVariable(
        getModule(), ATy, false, llvm::GlobalValue::InternalLinkage,
        llvm::ConstantArray::get(ATy, UsedArray), "__clang_gpu_used_external");
    addCompilerUsedGlobal(GV);
  }
 
  emitLLVMUsed();
  if (SanStats)
    SanStats->finish();
 
  if (CodeGenOpts.Autolink &&
      (Context.getLangOpts().Modules || !LinkerOptionsMetadata.empty())) {
    EmitModuleLinkOptions();
  }
 
  // On ELF we pass the dependent library specifiers directly to the linker
  // without manipulating them. This is in contrast to other platforms where
  // they are mapped to a specific linker option by the compiler. This
  // difference is a result of the greater variety of ELF linkers and the fact
  // that ELF linkers tend to handle libraries in a more complicated fashion
  // than on other platforms. This forces us to defer handling the dependent
  // libs to the linker.
  //
  // CUDA/HIP device and host libraries are different. Currently there is no
  // way to differentiate dependent libraries for host or device. Existing
  // usage of #pragma comment(lib, *) is intended for host libraries on
  // Windows. Therefore emit llvm.dependent-libraries only for host.
  if (!ELFDependentLibraries.empty() && !Context.getLangOpts().CUDAIsDevice) {
    auto *NMD = getModule().getOrInsertNamedMetadata("llvm.dependent-libraries");
    for (auto *MD : ELFDependentLibraries)
      NMD->addOperand(MD);
  }
 
  // Record mregparm value now so it is visible through rest of codegen.
  if (Context.getTargetInfo().getTriple().getArch() == llvm::Triple::x86)
    getModule().addModuleFlag(llvm::Module::Error, "NumRegisterParameters",
                              CodeGenOpts.NumRegisterParameters);
 
  if (CodeGenOpts.DwarfVersion) {
    getModule().addModuleFlag(llvm::Module::Max, "Dwarf Version",
                              CodeGenOpts.DwarfVersion);
  }
 
  if (CodeGenOpts.Dwarf64)
    getModule().addModuleFlag(llvm::Module::Max, "DWARF64", 1);
 
  if (Context.getLangOpts().SemanticInterposition)
    // Require various optimization to respect semantic interposition.
    getModule().setSemanticInterposition(true);
 
  if (CodeGenOpts.EmitCodeView) {
    // Indicate that we want CodeView in the metadata.
    getModule().addModuleFlag(llvm::Module::Warning, "CodeView", 1);
  }
  if (CodeGenOpts.CodeViewGHash) {
    getModule().addModuleFlag(llvm::Module::Warning, "CodeViewGHash", 1);
  }
  if (CodeGenOpts.ControlFlowGuard) {
    // Function ID tables and checks for Control Flow Guard (cfguard=2).
    getModule().addModuleFlag(llvm::Module::Warning, "cfguard", 2);
  } else if (CodeGenOpts.ControlFlowGuardNoChecks) {
    // Function ID tables for Control Flow Guard (cfguard=1).
    getModule().addModuleFlag(llvm::Module::Warning, "cfguard", 1);
  }
  if (CodeGenOpts.EHContGuard) {
    // Function ID tables for EH Continuation Guard.
    getModule().addModuleFlag(llvm::Module::Warning, "ehcontguard", 1);
  }
  if (Context.getLangOpts().Kernel) {
    // Note if we are compiling with /kernel.
    getModule().addModuleFlag(llvm::Module::Warning, "ms-kernel", 1);
  }
  if (CodeGenOpts.OptimizationLevel > 0 && CodeGenOpts.StrictVTablePointers) {
    // We don't support LTO with 2 with different StrictVTablePointers
    // FIXME: we could support it by stripping all the information introduced
    // by StrictVTablePointers.
 
    getModule().addModuleFlag(llvm::Module::Error, "StrictVTablePointers",1);
 
    llvm::Metadata *Ops[2] = {
              llvm::MDString::get(VMContext, "StrictVTablePointers"),
              llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
                  llvm::Type::getInt32Ty(VMContext), 1))};
 
    getModule().addModuleFlag(llvm::Module::Require,
                              "StrictVTablePointersRequirement",
                              llvm::MDNode::get(VMContext, Ops));
  }
  if (getModuleDebugInfo())
    // We support a single version in the linked module. The LLVM
    // parser will drop debug info with a different version number
    // (and warn about it, too).
    getModule().addModuleFlag(llvm::Module::Warning, "Debug Info Version",
                              llvm::DEBUG_METADATA_VERSION);
 
  // We need to record the widths of enums and wchar_t, so that we can generate
  // the correct build attributes in the ARM backend. wchar_size is also used by
  // TargetLibraryInfo.
  uint64_t WCharWidth =
      Context.getTypeSizeInChars(Context.getWideCharType()).getQuantity();
  getModule().addModuleFlag(llvm::Module::Error, "wchar_size", WCharWidth);
 
  llvm::Triple::ArchType Arch = Context.getTargetInfo().getTriple().getArch();
  if (   Arch == llvm::Triple::arm
      || Arch == llvm::Triple::armeb
      || Arch == llvm::Triple::thumb
      || Arch == llvm::Triple::thumbeb) {
    // The minimum width of an enum in bytes
    uint64_t EnumWidth = Context.getLangOpts().ShortEnums ? 1 : 4;
    getModule().addModuleFlag(llvm::Module::Error, "min_enum_size", EnumWidth);
  }
 
  if (Arch == llvm::Triple::riscv32 || Arch == llvm::Triple::riscv64) {
    StringRef ABIStr = Target.getABI();
    llvm::LLVMContext &Ctx = TheModule.getContext();
    getModule().addModuleFlag(llvm::Module::Error, "target-abi",
                              llvm::MDString::get(Ctx, ABIStr));
  }
 
  if (CodeGenOpts.SanitizeCfiCrossDso) {
    // Indicate that we want cross-DSO control flow integrity checks.
    getModule().addModuleFlag(llvm::Module::Override, "Cross-DSO CFI", 1);
  }
 
  if (CodeGenOpts.WholeProgramVTables) {
    // Indicate whether VFE was enabled for this module, so that the
    // vcall_visibility metadata added under whole program vtables is handled
    // appropriately in the optimizer.
    getModule().addModuleFlag(llvm::Module::Error, "Virtual Function Elim",
                              CodeGenOpts.VirtualFunctionElimination);
  }
 
  if (LangOpts.Sanitize.has(SanitizerKind::CFIICall)) {
    getModule().addModuleFlag(llvm::Module::Override,
                              "CFI Canonical Jump Tables",
                              CodeGenOpts.SanitizeCfiCanonicalJumpTables);
  }
 
  if (LangOpts.Sanitize.has(SanitizerKind::KCFI)) {
    getModule().addModuleFlag(llvm::Module::Override, "kcfi", 1);
    // KCFI assumes patchable-function-prefix is the same for all indirectly
    // called functions. Store the expected offset for code generation.
    if (CodeGenOpts.PatchableFunctionEntryOffset)
      getModule().addModuleFlag(llvm::Module::Override, "kcfi-offset",
                                CodeGenOpts.PatchableFunctionEntryOffset);
  }
 
  if (CodeGenOpts.CFProtectionReturn &&
      Target.checkCFProtectionReturnSupported(getDiags())) {
    // Indicate that we want to instrument return control flow protection.
    getModule().addModuleFlag(llvm::Module::Min, "cf-protection-return",
                              1);
  }
 
  if (CodeGenOpts.CFProtectionBranch &&
      Target.checkCFProtectionBranchSupported(getDiags())) {
    // Indicate that we want to instrument branch control flow protection.
    getModule().addModuleFlag(llvm::Module::Min, "cf-protection-branch",
                              1);
  }
 
  if (CodeGenOpts.FunctionReturnThunks)
    getModule().addModuleFlag(llvm::Module::Override, "function_return_thunk_extern", 1);
 
  if (CodeGenOpts.IndirectBranchCSPrefix)
    getModule().addModuleFlag(llvm::Module::Override, "indirect_branch_cs_prefix", 1);
 
  // Add module metadata for return address signing (ignoring
  // non-leaf/all) and stack tagging. These are actually turned on by function
  // attributes, but we use module metadata to emit build attributes. This is
  // needed for LTO, where the function attributes are inside bitcode
  // serialised into a global variable by the time build attributes are
  // emitted, so we can't access them. LTO objects could be compiled with
  // different flags therefore module flags are set to "Min" behavior to achieve
  // the same end result of the normal build where e.g BTI is off if any object
  // doesn't support it.
  if (Context.getTargetInfo().hasFeature("ptrauth") &&
      LangOpts.getSignReturnAddressScope() !=
          LangOptions::SignReturnAddressScopeKind::None)
    getModule().addModuleFlag(llvm::Module::Override,
                              "sign-return-address-buildattr", 1);
  if (LangOpts.Sanitize.has(SanitizerKind::MemtagStack))
    getModule().addModuleFlag(llvm::Module::Override,
                              "tag-stack-memory-buildattr", 1);
 
  if (Arch == llvm::Triple::thumb || Arch == llvm::Triple::thumbeb ||
      Arch == llvm::Triple::arm || Arch == llvm::Triple::armeb ||
      Arch == llvm::Triple::aarch64 || Arch == llvm::Triple::aarch64_32 ||
      Arch == llvm::Triple::aarch64_be) {
    if (LangOpts.BranchTargetEnforcement)
      getModule().addModuleFlag(llvm::Module::Min, "branch-target-enforcement",
                                1);
    if (LangOpts.hasSignReturnAddress())
      getModule().addModuleFlag(llvm::Module::Min, "sign-return-address", 1);
    if (LangOpts.isSignReturnAddressScopeAll())
      getModule().addModuleFlag(llvm::Module::Min, "sign-return-address-all",
                                1);
    if (!LangOpts.isSignReturnAddressWithAKey())
      getModule().addModuleFlag(llvm::Module::Min,
                                "sign-return-address-with-bkey", 1);
  }
 
  if (!CodeGenOpts.MemoryProfileOutput.empty()) {
    llvm::LLVMContext &Ctx = TheModule.getContext();
    getModule().addModuleFlag(
        llvm::Module::Error, "MemProfProfileFilename",
        llvm::MDString::get(Ctx, CodeGenOpts.MemoryProfileOutput));
  }
 
  if (LangOpts.CUDAIsDevice && getTriple().isNVPTX()) {
    // Indicate whether __nvvm_reflect should be configured to flush denormal
    // floating point values to 0.  (This corresponds to its "__CUDA_FTZ"
    // property.)
    getModule().addModuleFlag(llvm::Module::Override, "nvvm-reflect-ftz",
                              CodeGenOpts.FP32DenormalMode.Output !=
                                  llvm::DenormalMode::IEEE);
  }
 
  if (LangOpts.EHAsynch)
    getModule().addModuleFlag(llvm::Module::Warning, "eh-asynch", 1);
 
  // Indicate whether this Module was compiled with -fopenmp
  if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd)
    getModule().addModuleFlag(llvm::Module::Max, "openmp", LangOpts.OpenMP);
  if (getLangOpts().OpenMPIsTargetDevice)
    getModule().addModuleFlag(llvm::Module::Max, "openmp-device",
                              LangOpts.OpenMP);
 
  // Emit OpenCL specific module metadata: OpenCL/SPIR version.
  if (LangOpts.OpenCL || (LangOpts.CUDAIsDevice && getTriple().isSPIRV())) {
    EmitOpenCLMetadata();
    // Emit SPIR version.
    if (getTriple().isSPIR()) {
      // SPIR v2.0 s2.12 - The SPIR version used by the module is stored in the
      // opencl.spir.version named metadata.
      // C++ for OpenCL has a distinct mapping for version compatibility with
      // OpenCL.
      auto Version = LangOpts.getOpenCLCompatibleVersion();
      llvm::Metadata *SPIRVerElts[] = {
          llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
              Int32Ty, Version / 100)),
          llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
              Int32Ty, (Version / 100 > 1) ? 0 : 2))};
      llvm::NamedMDNode *SPIRVerMD =
          TheModule.getOrInsertNamedMetadata("opencl.spir.version");
      llvm::LLVMContext &Ctx = TheModule.getContext();
      SPIRVerMD->addOperand(llvm::MDNode::get(Ctx, SPIRVerElts));
    }
  }
 
  // HLSL related end of code gen work items.
  if (LangOpts.HLSL)
    getHLSLRuntime().finishCodeGen();
 
  if (uint32_t PLevel = Context.getLangOpts().PICLevel) {
    assert(PLevel < 3 && "Invalid PIC Level");
    getModule().setPICLevel(static_cast<llvm::PICLevel::Level>(PLevel));
    if (Context.getLangOpts().PIE)
      getModule().setPIELevel(static_cast<llvm::PIELevel::Level>(PLevel));
  }
 
  if (getCodeGenOpts().CodeModel.size() > 0) {
    unsigned CM = llvm::StringSwitch<unsigned>(getCodeGenOpts().CodeModel)
                  .Case("tiny", llvm::CodeModel::Tiny)
                  .Case("small", llvm::CodeModel::Small)
                  .Case("kernel", llvm::CodeModel::Kernel)
                  .Case("medium", llvm::CodeModel::Medium)
                  .Case("large", llvm::CodeModel::Large)
                  .Default(~0u);
    if (CM != ~0u) {
      llvm::CodeModel::Model codeModel = static_cast<llvm::CodeModel::Model>(CM);
      getModule().setCodeModel(codeModel);
 
      if (CM == llvm::CodeModel::Medium &&
          Context.getTargetInfo().getTriple().getArch() ==
              llvm::Triple::x86_64) {
        getModule().setLargeDataThreshold(getCodeGenOpts().LargeDataThreshold);
      }
    }
  }
 
  if (CodeGenOpts.NoPLT)
    getModule().setRtLibUseGOT();
  if (getTriple().isOSBinFormatELF() &&
      CodeGenOpts.DirectAccessExternalData !=
          getModule().getDirectAccessExternalData()) {
    getModule().setDirectAccessExternalData(
        CodeGenOpts.DirectAccessExternalData);
  }
  if (CodeGenOpts.UnwindTables)
    getModule().setUwtable(llvm::UWTableKind(CodeGenOpts.UnwindTables));
 
  switch (CodeGenOpts.getFramePointer()) {
  case CodeGenOptions::FramePointerKind::None:
    // 0 ("none") is the default.
    break;
  case CodeGenOptions::FramePointerKind::NonLeaf:
    getModule().setFramePointer(llvm::FramePointerKind::NonLeaf);
    break;
  case CodeGenOptions::FramePointerKind::All:
    getModule().setFramePointer(llvm::FramePointerKind::All);
    break;
  }
 
  SimplifyPersonality();
 
  if (getCodeGenOpts().EmitDeclMetadata)
    EmitDeclMetadata();
 
  if (getCodeGenOpts().CoverageNotesFile.size() ||
      getCodeGenOpts().CoverageDataFile.size())
    EmitCoverageFile();
 
  if (CGDebugInfo *DI = getModuleDebugInfo())
    DI->finalize();
 
  if (getCodeGenOpts().EmitVersionIdentMetadata)
    EmitVersionIdentMetadata();
 
  if (!getCodeGenOpts().RecordCommandLine.empty())
    EmitCommandLineMetadata();
 
  if (!getCodeGenOpts().StackProtectorGuard.empty())
    getModule().setStackProtectorGuard(getCodeGenOpts().StackProtectorGuard);
  if (!getCodeGenOpts().StackProtectorGuardReg.empty())
    getModule().setStackProtectorGuardReg(
        getCodeGenOpts().StackProtectorGuardReg);
  if (!getCodeGenOpts().StackProtectorGuardSymbol.empty())
    getModule().setStackProtectorGuardSymbol(
        getCodeGenOpts().StackProtectorGuardSymbol);
  if (getCodeGenOpts().StackProtectorGuardOffset != INT_MAX)
    getModule().setStackProtectorGuardOffset(
        getCodeGenOpts().StackProtectorGuardOffset);
  if (getCodeGenOpts().StackAlignment)
    getModule().setOverrideStackAlignment(getCodeGenOpts().StackAlignment);
  if (getCodeGenOpts().SkipRaxSetup)
    getModule().addModuleFlag(llvm::Module::Override, "SkipRaxSetup", 1);
  if (getLangOpts().RegCall4)
    getModule().addModuleFlag(llvm::Module::Override, "RegCallv4", 1);
 
  if (getContext().getTargetInfo().getMaxTLSAlign())
    getModule().addModuleFlag(llvm::Module::Error, "MaxTLSAlign",
                              getContext().getTargetInfo().getMaxTLSAlign());
 
  getTargetCodeGenInfo().emitTargetGlobals(*this);
 
  getTargetCodeGenInfo().emitTargetMetadata(*this, MangledDeclNames);
 
  EmitBackendOptionsMetadata(getCodeGenOpts());
 
  // If there is device offloading code embed it in the host now.
  EmbedObject(&getModule(), CodeGenOpts, getDiags());
 
  // Set visibility from DLL storage class
  // We do this at the end of LLVM IR generation; after any operation
  // that might affect the DLL storage class or the visibility, and
  // before anything that might act on these.
  setVisibilityFromDLLStorageClass(LangOpts, getModule());
}
 
void CodeGenModule::EmitOpenCLMetadata() {
  // SPIR v2.0 s2.13 - The OpenCL version used by the module is stored in the
  // opencl.ocl.version named metadata node.
  // C++ for OpenCL has a distinct mapping for versions compatibile with OpenCL.
  auto Version = LangOpts.getOpenCLCompatibleVersion();
  llvm::Metadata *OCLVerElts[] = {
      llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
          Int32Ty, Version / 100)),
      llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
          Int32Ty, (Version % 100) / 10))};
  llvm::NamedMDNode *OCLVerMD =
      TheModule.getOrInsertNamedMetadata("opencl.ocl.version");
  llvm::LLVMContext &Ctx = TheModule.getContext();
  OCLVerMD->addOperand(llvm::MDNode::get(Ctx, OCLVerElts));
}
 
void CodeGenModule::EmitBackendOptionsMetadata(
    const CodeGenOptions &CodeGenOpts) {
  if (getTriple().isRISCV()) {
    getModule().addModuleFlag(llvm::Module::Min, "SmallDataLimit",
                              CodeGenOpts.SmallDataLimit);
  }
}
 
void CodeGenModule::UpdateCompletedType(const TagDecl *TD) {
  // Make sure that this type is translated.
  Types.UpdateCompletedType(TD);
}
 
void CodeGenModule::RefreshTypeCacheForClass(const CXXRecordDecl *RD) {
  // Make sure that this type is translated.
  Types.RefreshTypeCacheForClass(RD);
}
 
llvm::MDNode *CodeGenModule::getTBAATypeInfo(QualType QTy) {
  if (!TBAA)
    return nullptr;
  return TBAA->getTypeInfo(QTy);
}
 
TBAAAccessInfo CodeGenModule::getTBAAAccessInfo(QualType AccessType) {
  if (!TBAA)
    return TBAAAccessInfo();
  if (getLangOpts().CUDAIsDevice) {
    // As CUDA builtin surface/texture types are replaced, skip generating TBAA
    // access info.
    if (AccessType->isCUDADeviceBuiltinSurfaceType()) {
      if (getTargetCodeGenInfo().getCUDADeviceBuiltinSurfaceDeviceType() !=
          nullptr)
        return TBAAAccessInfo();
    } else if (AccessType->isCUDADeviceBuiltinTextureType()) {
      if (getTargetCodeGenInfo().getCUDADeviceBuiltinTextureDeviceType() !=
          nullptr)
        return TBAAAccessInfo();
    }
  }
  return TBAA->getAccessInfo(AccessType);
}
 
TBAAAccessInfo
CodeGenModule::getTBAAVTablePtrAccessInfo(llvm::Type *VTablePtrType) {
  if (!TBAA)
    return TBAAAccessInfo();
  return TBAA->getVTablePtrAccessInfo(VTablePtrType);
}
 
llvm::MDNode *CodeGenModule::getTBAAStructInfo(QualType QTy) {
  if (!TBAA)
    return nullptr;
  return TBAA->getTBAAStructInfo(QTy);
}
 
llvm::MDNode *CodeGenModule::getTBAABaseTypeInfo(QualType QTy) {
  if (!TBAA)
    return nullptr;
  return TBAA->getBaseTypeInfo(QTy);
}
 
llvm::MDNode *CodeGenModule::getTBAAAccessTagInfo(TBAAAccessInfo Info) {
  if (!TBAA)
    return nullptr;
  return TBAA->getAccessTagInfo(Info);
}
 
TBAAAccessInfo CodeGenModule::mergeTBAAInfoForCast(TBAAAccessInfo SourceInfo,
                                                   TBAAAccessInfo TargetInfo) {
  if (!TBAA)
    return TBAAAccessInfo();
  return TBAA->mergeTBAAInfoForCast(SourceInfo, TargetInfo);
}
 
TBAAAccessInfo
CodeGenModule::mergeTBAAInfoForConditionalOperator(TBAAAccessInfo InfoA,
                                                   TBAAAccessInfo InfoB) {
  if (!TBAA)
    return TBAAAccessInfo();
  return TBAA->mergeTBAAInfoForConditionalOperator(InfoA, InfoB);
}
 
TBAAAccessInfo
CodeGenModule::mergeTBAAInfoForMemoryTransfer(TBAAAccessInfo DestInfo,
                                              TBAAAccessInfo SrcInfo) {
  if (!TBAA)
    return TBAAAccessInfo();
  return TBAA->mergeTBAAInfoForConditionalOperator(DestInfo, SrcInfo);
}
 
void CodeGenModule::DecorateInstructionWithTBAA(llvm::Instruction *Inst,
                                                TBAAAccessInfo TBAAInfo) {
  if (llvm::MDNode *Tag = getTBAAAccessTagInfo(TBAAInfo))
    Inst->setMetadata(llvm::LLVMContext::MD_tbaa, Tag);
}
 
void CodeGenModule::DecorateInstructionWithInvariantGroup(
    llvm::Instruction *I, const CXXRecordDecl *RD) {
  I->setMetadata(llvm::LLVMContext::MD_invariant_group,
                 llvm::MDNode::get(getLLVMContext(), {}));
}
 
void CodeGenModule::Error(SourceLocation loc, StringRef message) {
  unsigned diagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error, "%0");
  getDiags().Report(Context.getFullLoc(loc), diagID) << message;
}
 
/// ErrorUnsupported - Print out an error that codegen doesn't support the
/// specified stmt yet.
void CodeGenModule::ErrorUnsupported(const Stmt *S, const char *Type) {
  unsigned DiagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error,
                                               "cannot compile this %0 yet");
  std::string Msg = Type;
  getDiags().Report(Context.getFullLoc(S->getBeginLoc()), DiagID)
      << Msg << S->getSourceRange();
}
 
/// ErrorUnsupported - Print out an error that codegen doesn't support the
/// specified decl yet.
void CodeGenModule::ErrorUnsupported(const Decl *D, const char *Type) {
  unsigned DiagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error,
                                               "cannot compile this %0 yet");
  std::string Msg = Type;
  getDiags().Report(Context.getFullLoc(D->getLocation()), DiagID) << Msg;
}
 
llvm::ConstantInt *CodeGenModule::getSize(CharUnits size) {
  return llvm::ConstantInt::get(SizeTy, size.getQuantity());
}
 
void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV,
                                        const NamedDecl *D) const {
  // Internal definitions always have default visibility.
  if (GV->hasLocalLinkage()) {
    GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
    return;
  }
  if (!D)
    return;
  // Set visibility for definitions, and for declarations if requested globally
  // or set explicitly.
  LinkageInfo LV = D->getLinkageAndVisibility();
  if (GV->hasDLLExportStorageClass() || GV->hasDLLImportStorageClass()) {
    // Reject incompatible dlllstorage and visibility annotations.
    if (!LV.isVisibilityExplicit())
      return;
    if (GV->hasDLLExportStorageClass()) {
      if (LV.getVisibility() == HiddenVisibility)
        getDiags().Report(D->getLocation(),
                          diag::err_hidden_visibility_dllexport);
    } else if (LV.getVisibility() != DefaultVisibility) {
      getDiags().Report(D->getLocation(),
                        diag::err_non_default_visibility_dllimport);
    }
    return;
  }
 
  if (LV.isVisibilityExplicit() || getLangOpts().SetVisibilityForExternDecls ||
      !GV->isDeclarationForLinker())
    GV->setVisibility(GetLLVMVisibility(LV.getVisibility()));
}
 
static bool shouldAssumeDSOLocal(const CodeGenModule &CGM,
                                 llvm::GlobalValue *GV) {
  if (GV->hasLocalLinkage())
    return true;
 
  if (!GV->hasDefaultVisibility() && !GV->hasExternalWeakLinkage())
    return true;
 
  // DLLImport explicitly marks the GV as external.
  if (GV->hasDLLImportStorageClass())
    return false;
 
  const llvm::Triple &TT = CGM.getTriple();
  const auto &CGOpts = CGM.getCodeGenOpts();
  if (TT.isWindowsGNUEnvironment()) {
    // In MinGW, variables without DLLImport can still be automatically
    // imported from a DLL by the linker; don't mark variables that
    // potentially could come from another DLL as DSO local.
 
    // With EmulatedTLS, TLS variables can be autoimported from other DLLs
    // (and this actually happens in the public interface of libstdc++), so
    // such variables can't be marked as DSO local. (Native TLS variables
    // can't be dllimported at all, though.)
    if (GV->isDeclarationForLinker() && isa<llvm::GlobalVariable>(GV) &&
        (!GV->isThreadLocal() || CGM.getCodeGenOpts().EmulatedTLS) &&
        CGOpts.AutoImport)
      return false;
  }
 
  // On COFF, don't mark 'extern_weak' symbols as DSO local. If these symbols
  // remain unresolved in the link, they can be resolved to zero, which is
  // outside the current DSO.
  if (TT.isOSBinFormatCOFF() && GV->hasExternalWeakLinkage())
    return false;
 
  // Every other GV is local on COFF.
  // Make an exception for windows OS in the triple: Some firmware builds use
  // *-win32-macho triples. This (accidentally?) produced windows relocations
  // without GOT tables in older clang versions; Keep this behaviour.
  // FIXME: even thread local variables?
  if (TT.isOSBinFormatCOFF() || (TT.isOSWindows() && TT.isOSBinFormatMachO()))
    return true;
 
  // Only handle COFF and ELF for now.
  if (!TT.isOSBinFormatELF())
    return false;
 
  // If this is not an executable, don't assume anything is local.
  llvm::Reloc::Model RM = CGOpts.RelocationModel;
  const auto &LOpts = CGM.getLangOpts();
  if (RM != llvm::Reloc::Static && !LOpts.PIE) {
    // On ELF, if -fno-semantic-interposition is specified and the target
    // supports local aliases, there will be neither CC1
    // -fsemantic-interposition nor -fhalf-no-semantic-interposition. Set
    // dso_local on the function if using a local alias is preferable (can avoid
    // PLT indirection).
    if (!(isa<llvm::Function>(GV) && GV->canBenefitFromLocalAlias()))
      return false;
    return !(CGM.getLangOpts().SemanticInterposition ||
             CGM.getLangOpts().HalfNoSemanticInterposition);
  }
 
  // A definition cannot be preempted from an executable.
  if (!GV->isDeclarationForLinker())
    return true;
 
  // Most PIC code sequences that assume that a symbol is local cannot produce a
  // 0 if it turns out the symbol is undefined. While this is ABI and relocation
  // depended, it seems worth it to handle it here.
  if (RM == llvm::Reloc::PIC_ && GV->hasExternalWeakLinkage())
    return false;
 
  // PowerPC64 prefers TOC indirection to avoid copy relocations.
  if (TT.isPPC64())
    return false;
 
  if (CGOpts.DirectAccessExternalData) {
    // If -fdirect-access-external-data (default for -fno-pic), set dso_local
    // for non-thread-local variables. If the symbol is not defined in the
    // executable, a copy relocation will be needed at link time. dso_local is
    // excluded for thread-local variables because they generally don't support
    // copy relocations.
    if (auto *Var = dyn_cast<llvm::GlobalVariable>(GV))
      if (!Var->isThreadLocal())
        return true;
 
    // -fno-pic sets dso_local on a function declaration to allow direct
    // accesses when taking its address (similar to a data symbol). If the
    // function is not defined in the executable, a canonical PLT entry will be
    // needed at link time. -fno-direct-access-external-data can avoid the
    // canonical PLT entry. We don't generalize this condition to -fpie/-fpic as
    // it could just cause trouble without providing perceptible benefits.
    if (isa<llvm::Function>(GV) && !CGOpts.NoPLT && RM == llvm::Reloc::Static)
      return true;
  }
 
  // If we can use copy relocations we can assume it is local.
 
  // Otherwise don't assume it is local.
  return false;
}
 
void CodeGenModule::setDSOLocal(llvm::GlobalValue *GV) const {
  GV->setDSOLocal(shouldAssumeDSOLocal(*this, GV));
}
 
void CodeGenModule::setDLLImportDLLExport(llvm::GlobalValue *GV,
                                          GlobalDecl GD) const {
  const auto *D = dyn_cast<NamedDecl>(GD.getDecl());
  // C++ destructors have a few C++ ABI specific special cases.
  if (const auto *Dtor = dyn_cast_or_null<CXXDestructorDecl>(D)) {
    getCXXABI().setCXXDestructorDLLStorage(GV, Dtor, GD.getDtorType());
    return;
  }
  setDLLImportDLLExport(GV, D);
}
 
void CodeGenModule::setDLLImportDLLExport(llvm::GlobalValue *GV,
                                          const NamedDecl *D) const {
  if (D && D->isExternallyVisible()) {
    if (D->hasAttr<DLLImportAttr>())
      GV->setDLLStorageClass(llvm::GlobalVariable::DLLImportStorageClass);
    else if ((D->hasAttr<DLLExportAttr>() ||
              shouldMapVisibilityToDLLExport(D)) &&
             !GV->isDeclarationForLinker())
      GV->setDLLStorageClass(llvm::GlobalVariable::DLLExportStorageClass);
  }
}
 
void CodeGenModule::setGVProperties(llvm::GlobalValue *GV,
                                    GlobalDecl GD) const {
  setDLLImportDLLExport(GV, GD);
  setGVPropertiesAux(GV, dyn_cast<NamedDecl>(GD.getDecl()));
}
 
void CodeGenModule::setGVProperties(llvm::GlobalValue *GV,
                                    const NamedDecl *D) const {
  setDLLImportDLLExport(GV, D);
  setGVPropertiesAux(GV, D);
}
 
void CodeGenModule::setGVPropertiesAux(llvm::GlobalValue *GV,
                                       const NamedDecl *D) const {
  setGlobalVisibility(GV, D);
  setDSOLocal(GV);
  GV->setPartition(CodeGenOpts.SymbolPartition);
}
 
static llvm::GlobalVariable::ThreadLocalMode GetLLVMTLSModel(StringRef S) {
  return llvm::StringSwitch<llvm::GlobalVariable::ThreadLocalMode>(S)
      .Case("global-dynamic", llvm::GlobalVariable::GeneralDynamicTLSModel)
      .Case("local-dynamic", llvm::GlobalVariable::LocalDynamicTLSModel)
      .Case("initial-exec", llvm::GlobalVariable::InitialExecTLSModel)
      .Case("local-exec", llvm::GlobalVariable::LocalExecTLSModel);
}
 
llvm::GlobalVariable::ThreadLocalMode
CodeGenModule::GetDefaultLLVMTLSModel() const {
  switch (CodeGenOpts.getDefaultTLSModel()) {
  case CodeGenOptions::GeneralDynamicTLSModel:
    return llvm::GlobalVariable::GeneralDynamicTLSModel;
  case CodeGenOptions::LocalDynamicTLSModel:
    return llvm::GlobalVariable::LocalDynamicTLSModel;
  case CodeGenOptions::InitialExecTLSModel:
    return llvm::GlobalVariable::InitialExecTLSModel;
  case CodeGenOptions::LocalExecTLSModel:
    return llvm::GlobalVariable::LocalExecTLSModel;
  }
  llvm_unreachable("Invalid TLS model!");
}
 
void CodeGenModule::setTLSMode(llvm::GlobalValue *GV, const VarDecl &D) const {
  assert(D.getTLSKind() && "setting TLS mode on non-TLS var!");
 
  llvm::GlobalValue::ThreadLocalMode TLM;
  TLM = GetDefaultLLVMTLSModel();
 
  // Override the TLS model if it is explicitly specified.
  if (const TLSModelAttr *Attr = D.getAttr<TLSModelAttr>()) {
    TLM = GetLLVMTLSModel(Attr->getModel());
  }
 
  GV->setThreadLocalMode(TLM);
}
 
static std::string getCPUSpecificMangling(const CodeGenModule &CGM,
                                          StringRef Name) {
  const TargetInfo &Target = CGM.getTarget();
  return (Twine('.') + Twine(Target.CPUSpecificManglingCharacter(Name))).str();
}
 
static void AppendCPUSpecificCPUDispatchMangling(const CodeGenModule &CGM,
                                                 const CPUSpecificAttr *Attr,
                                                 unsigned CPUIndex,
                                                 raw_ostream &Out) {
  // cpu_specific gets the current name, dispatch gets the resolver if IFunc is
  // supported.
  if (Attr)
    Out << getCPUSpecificMangling(CGM, Attr->getCPUName(CPUIndex)->getName());
  else if (CGM.getTarget().supportsIFunc())
    Out << ".resolver";
}
 
static void AppendTargetVersionMangling(const CodeGenModule &CGM,
                                        const TargetVersionAttr *Attr,
                                        raw_ostream &Out) {
  if (Attr->isDefaultVersion())
    return;
  Out << "._";
  const TargetInfo &TI = CGM.getTarget();
  llvm::SmallVector<StringRef, 8> Feats;
  Attr->getFeatures(Feats);
  llvm::stable_sort(Feats, [&TI](const StringRef FeatL, const StringRef FeatR) {
    return TI.multiVersionSortPriority(FeatL) <
           TI.multiVersionSortPriority(FeatR);
  });
  for (const auto &Feat : Feats) {
    Out << 'M';
    Out << Feat;
  }
}
 
static void AppendTargetMangling(const CodeGenModule &CGM,
                                 const TargetAttr *Attr, raw_ostream &Out) {
  if (Attr->isDefaultVersion())
    return;
 
  Out << '.';
  const TargetInfo &Target = CGM.getTarget();
  ParsedTargetAttr Info = Target.parseTargetAttr(Attr->getFeaturesStr());
  llvm::sort(Info.Features, [&Target](StringRef LHS, StringRef RHS) {
    // Multiversioning doesn't allow "no-${feature}", so we can
    // only have "+" prefixes here.
    assert(LHS.startswith("+") && RHS.startswith("+") &&
           "Features should always have a prefix.");
    return Target.multiVersionSortPriority(LHS.substr(1)) >
           Target.multiVersionSortPriority(RHS.substr(1));
  });
 
  bool IsFirst = true;
 
  if (!Info.CPU.empty()) {
    IsFirst = false;
    Out << "arch_" << Info.CPU;
  }
 
  for (StringRef Feat : Info.Features) {
    if (!IsFirst)
      Out << '_';
    IsFirst = false;
    Out << Feat.substr(1);
  }
}
 
// Returns true if GD is a function decl with internal linkage and
// needs a unique suffix after the mangled name.
static bool isUniqueInternalLinkageDecl(GlobalDecl GD,
                                        CodeGenModule &CGM) {
  const Decl *D = GD.getDecl();
  return !CGM.getModuleNameHash().empty() && isa<FunctionDecl>(D) &&
         (CGM.getFunctionLinkage(GD) == llvm::GlobalValue::InternalLinkage);
}
 
static void AppendTargetClonesMangling(const CodeGenModule &CGM,
                                       const TargetClonesAttr *Attr,
                                       unsigned VersionIndex,
                                       raw_ostream &Out) {
  const TargetInfo &TI = CGM.getTarget();
  if (TI.getTriple().isAArch64()) {
    StringRef FeatureStr = Attr->getFeatureStr(VersionIndex);
    if (FeatureStr == "default")
      return;
    Out << "._";
    SmallVector<StringRef, 8> Features;
    FeatureStr.split(Features, "+");
    llvm::stable_sort(Features,
                      [&TI](const StringRef FeatL, const StringRef FeatR) {
                        return TI.multiVersionSortPriority(FeatL) <
                               TI.multiVersionSortPriority(FeatR);
                      });
    for (auto &Feat : Features) {
      Out << 'M';
      Out << Feat;
    }
  } else {
    Out << '.';
    StringRef FeatureStr = Attr->getFeatureStr(VersionIndex);
    if (FeatureStr.startswith("arch="))
      Out << "arch_" << FeatureStr.substr(sizeof("arch=") - 1);
    else
      Out << FeatureStr;
 
    Out << '.' << Attr->getMangledIndex(VersionIndex);
  }
}
 
static std::string getMangledNameImpl(CodeGenModule &CGM, GlobalDecl GD,
                                      const NamedDecl *ND,
                                      bool OmitMultiVersionMangling = false) {
  SmallString<256> Buffer;
  llvm::raw_svector_ostream Out(Buffer);
  MangleContext &MC = CGM.getCXXABI().getMangleContext();
  if (!CGM.getModuleNameHash().empty())
    MC.needsUniqueInternalLinkageNames();
  bool ShouldMangle = MC.shouldMangleDeclName(ND);
  if (ShouldMangle)
    MC.mangleName(GD.getWithDecl(ND), Out);
  else {
    IdentifierInfo *II = ND->getIdentifier();
    assert(II && "Attempt to mangle unnamed decl.");
    const auto *FD = dyn_cast<FunctionDecl>(ND);
 
    if (FD &&
        FD->getType()->castAs<FunctionType>()->getCallConv() == CC_X86RegCall) {
      if (CGM.getLangOpts().RegCall4)
        Out << "__regcall4__" << II->getName();
      else
        Out << "__regcall3__" << II->getName();
    } else if (FD && FD->hasAttr<CUDAGlobalAttr>() &&
               GD.getKernelReferenceKind() == KernelReferenceKind::Stub) {
      Out << "__device_stub__" << II->getName();
    } else {
      Out << II->getName();
    }
  }
 
  // Check if the module name hash should be appended for internal linkage
  // symbols.   This should come before multi-version target suffixes are
  // appended. This is to keep the name and module hash suffix of the
  // internal linkage function together.  The unique suffix should only be
  // added when name mangling is done to make sure that the final name can
  // be properly demangled.  For example, for C functions without prototypes,
  // name mangling is not done and the unique suffix should not be appeneded
  // then.
  if (ShouldMangle && isUniqueInternalLinkageDecl(GD, CGM)) {
    assert(CGM.getCodeGenOpts().UniqueInternalLinkageNames &&
           "Hash computed when not explicitly requested");
    Out << CGM.getModuleNameHash();
  }
 
  if (const auto *FD = dyn_cast<FunctionDecl>(ND))
    if (FD->isMultiVersion() && !OmitMultiVersionMangling) {
      switch (FD->getMultiVersionKind()) {
      case MultiVersionKind::CPUDispatch:
      case MultiVersionKind::CPUSpecific:
        AppendCPUSpecificCPUDispatchMangling(CGM,
                                             FD->getAttr<CPUSpecificAttr>(),
                                             GD.getMultiVersionIndex(), Out);
        break;
      case MultiVersionKind::Target:
        AppendTargetMangling(CGM, FD->getAttr<TargetAttr>(), Out);
        break;
      case MultiVersionKind::TargetVersion:
        AppendTargetVersionMangling(CGM, FD->getAttr<TargetVersionAttr>(), Out);
        break;
      case MultiVersionKind::TargetClones:
        AppendTargetClonesMangling(CGM, FD->getAttr<TargetClonesAttr>(),
                                   GD.getMultiVersionIndex(), Out);
        break;
      case MultiVersionKind::None:
        llvm_unreachable("None multiversion type isn't valid here");
      }
    }
 
  // Make unique name for device side static file-scope variable for HIP.
  if (CGM.getContext().shouldExternalize(ND) &&
      CGM.getLangOpts().GPURelocatableDeviceCode &&
      CGM.getLangOpts().CUDAIsDevice)
    CGM.printPostfixForExternalizedDecl(Out, ND);
 
  return std::string(Out.str());
}
 
void CodeGenModule::UpdateMultiVersionNames(GlobalDecl GD,
                                            const FunctionDecl *FD,
                                            StringRef &CurName) {
  if (!FD->isMultiVersion())
    return;
 
  // Get the name of what this would be without the 'target' attribute.  This
  // allows us to lookup the version that was emitted when this wasn't a
  // multiversion function.
  std::string NonTargetName =
      getMangledNameImpl(*this, GD, FD, /*OmitMultiVersionMangling=*/true);
  GlobalDecl OtherGD;
  if (lookupRepresentativeDecl(NonTargetName, OtherGD)) {
    assert(OtherGD.getCanonicalDecl()
               .getDecl()
               ->getAsFunction()
               ->isMultiVersion() &&
           "Other GD should now be a multiversioned function");
    // OtherFD is the version of this function that was mangled BEFORE
    // becoming a MultiVersion function.  It potentially needs to be updated.
    const FunctionDecl *OtherFD = OtherGD.getCanonicalDecl()
                                      .getDecl()
                                      ->getAsFunction()
                                      ->getMostRecentDecl();
    std::string OtherName = getMangledNameImpl(*this, OtherGD, OtherFD);
    // This is so that if the initial version was already the 'default'
    // version, we don't try to update it.
    if (OtherName != NonTargetName) {
      // Remove instead of erase, since others may have stored the StringRef
      // to this.
      const auto ExistingRecord = Manglings.find(NonTargetName);
      if (ExistingRecord != std::end(Manglings))
        Manglings.remove(&(*ExistingRecord));
      auto Result = Manglings.insert(std::make_pair(OtherName, OtherGD));
      StringRef OtherNameRef = MangledDeclNames[OtherGD.getCanonicalDecl()] =
          Result.first->first();
      // If this is the current decl is being created, make sure we update the name.
      if (GD.getCanonicalDecl() == OtherGD.getCanonicalDecl())
        CurName = OtherNameRef;
      if (llvm::GlobalValue *Entry = GetGlobalValue(NonTargetName))
        Entry->setName(OtherName);
    }
  }
}
 
StringRef CodeGenModule::getMangledName(GlobalDecl GD) {
  GlobalDecl CanonicalGD = GD.getCanonicalDecl();
 
  // Some ABIs don't have constructor variants.  Make sure that base and
  // complete constructors get mangled the same.
  if (const auto *CD = dyn_cast<CXXConstructorDecl>(CanonicalGD.getDecl())) {
    if (!getTarget().getCXXABI().hasConstructorVariants()) {
      CXXCtorType OrigCtorType = GD.getCtorType();
      assert(OrigCtorType == Ctor_Base || OrigCtorType == Ctor_Complete);
      if (OrigCtorType == Ctor_Base)
        CanonicalGD = GlobalDecl(CD, Ctor_Complete);
    }
  }
 
  // In CUDA/HIP device compilation with -fgpu-rdc, the mangled name of a
  // static device variable depends on whether the variable is referenced by
  // a host or device host function. Therefore the mangled name cannot be
  // cached.
  if (!LangOpts.CUDAIsDevice || !getContext().mayExternalize(GD.getDecl())) {
    auto FoundName = MangledDeclNames.find(CanonicalGD);
    if (FoundName != MangledDeclNames.end())
      return FoundName->second;
  }
 
  // Keep the first result in the case of a mangling collision.
  const auto *ND = cast<NamedDecl>(GD.getDecl());
  std::string MangledName = getMangledNameImpl(*this, GD, ND);
 
  // Ensure either we have different ABIs between host and device compilations,
  // says host compilation following MSVC ABI but device compilation follows
  // Itanium C++ ABI or, if they follow the same ABI, kernel names after
  // mangling should be the same after name stubbing. The later checking is
  // very important as the device kernel name being mangled in host-compilation
  // is used to resolve the device binaries to be executed. Inconsistent naming
  // result in undefined behavior. Even though we cannot check that naming
  // directly between host- and device-compilations, the host- and
  // device-mangling in host compilation could help catching certain ones.
  assert(!isa<FunctionDecl>(ND) || !ND->hasAttr<CUDAGlobalAttr>() ||
         getContext().shouldExternalize(ND) || getLangOpts().CUDAIsDevice ||
         (getContext().getAuxTargetInfo() &&
          (getContext().getAuxTargetInfo()->getCXXABI() !=
           getContext().getTargetInfo().getCXXABI())) ||
         getCUDARuntime().getDeviceSideName(ND) ==
             getMangledNameImpl(
                 *this,
                 GD.getWithKernelReferenceKind(KernelReferenceKind::Kernel),
                 ND));
 
  auto Result = Manglings.insert(std::make_pair(MangledName, GD));
  return MangledDeclNames[CanonicalGD] = Result.first->first();
}
 
StringRef CodeGenModule::getBlockMangledName(GlobalDecl GD,
                                             const BlockDecl *BD) {
  MangleContext &MangleCtx = getCXXABI().getMangleContext();
  const Decl *D = GD.getDecl();
 
  SmallString<256> Buffer;
  llvm::raw_svector_ostream Out(Buffer);
  if (!D)
    MangleCtx.mangleGlobalBlock(BD,
      dyn_cast_or_null<VarDecl>(initializedGlobalDecl.getDecl()), Out);
  else if (const auto *CD = dyn_cast<CXXConstructorDecl>(D))
    MangleCtx.mangleCtorBlock(CD, GD.getCtorType(), BD, Out);
  else if (const auto *DD = dyn_cast<CXXDestructorDecl>(D))
    MangleCtx.mangleDtorBlock(DD, GD.getDtorType(), BD, Out);
  else
    MangleCtx.mangleBlock(cast<DeclContext>(D), BD, Out);
 
  auto Result = Manglings.insert(std::make_pair(Out.str(), BD));
  return Result.first->first();
}
 
const GlobalDecl CodeGenModule::getMangledNameDecl(StringRef Name) {
  auto it = MangledDeclNames.begin();
  while (it != MangledDeclNames.end()) {
    if (it->second == Name)
      return it->first;
    it++;
  }
  return GlobalDecl();
}
 
llvm::GlobalValue *CodeGenModule::GetGlobalValue(StringRef Name) {
  return getModule().getNamedValue(Name);
}
 
/// AddGlobalCtor - Add a function to the list that will be called before
/// main() runs.
void CodeGenModule::AddGlobalCtor(llvm::Function *Ctor, int Priority,
                                  unsigned LexOrder,
                                  llvm::Constant *AssociatedData) {
  // FIXME: Type coercion of void()* types.
  GlobalCtors.push_back(Structor(Priority, LexOrder, Ctor, AssociatedData));
}
 
/// AddGlobalDtor - Add a function to the list that will be called
/// when the module is unloaded.
void CodeGenModule::AddGlobalDtor(llvm::Function *Dtor, int Priority,
                                  bool IsDtorAttrFunc) {
  if (CodeGenOpts.RegisterGlobalDtorsWithAtExit &&
      (!getContext().getTargetInfo().getTriple().isOSAIX() || IsDtorAttrFunc)) {
    DtorsUsingAtExit[Priority].push_back(Dtor);
    return;
  }
 
  // FIXME: Type coercion of void()* types.
  GlobalDtors.push_back(Structor(Priority, ~0U, Dtor, nullptr));
}
 
void CodeGenModule::EmitCtorList(CtorList &Fns, const char *GlobalName) {
  if (Fns.empty()) return;
 
  // Ctor function type is void()*.
  llvm::FunctionType* CtorFTy = llvm::FunctionType::get(VoidTy, false);
  llvm::Type *CtorPFTy = llvm::PointerType::get(CtorFTy,
      TheModule.getDataLayout().getProgramAddressSpace());
 
  // Get the type of a ctor entry, { i32, void ()*, i8* }.
  llvm::StructType *CtorStructTy = llvm::StructType::get(
      Int32Ty, CtorPFTy, VoidPtrTy);
 
  // Construct the constructor and destructor arrays.
  ConstantInitBuilder builder(*this);
  auto ctors = builder.beginArray(CtorStructTy);
  for (const auto &I : Fns) {
    auto ctor = ctors.beginStruct(CtorStructTy);
    ctor.addInt(Int32Ty, I.Priority);
    ctor.add(llvm::ConstantExpr::getBitCast(I.Initializer, CtorPFTy));
    if (I.AssociatedData)
      ctor.add(llvm::ConstantExpr::getBitCast(I.AssociatedData, VoidPtrTy));
    else
      ctor.addNullPointer(VoidPtrTy);
    ctor.finishAndAddTo(ctors);
  }
 
  auto list =
    ctors.finishAndCreateGlobal(GlobalName, getPointerAlign(),
                                /*constant*/ false,
                                llvm::GlobalValue::AppendingLinkage);
 
  // The LTO linker doesn't seem to like it when we set an alignment
  // on appending variables.  Take it off as a workaround.
  list->setAlignment(std::nullopt);
 
  Fns.clear();
}
 
llvm::GlobalValue::LinkageTypes
CodeGenModule::getFunctionLinkage(GlobalDecl GD) {
  const auto *D = cast<FunctionDecl>(GD.getDecl());
 
  GVALinkage Linkage = getContext().GetGVALinkageForFunction(D);
 
  if (const auto *Dtor = dyn_cast<CXXDestructorDecl>(D))
    return getCXXABI().getCXXDestructorLinkage(Linkage, Dtor, GD.getDtorType());
 
  return getLLVMLinkageForDeclarator(D, Linkage);
}
 
llvm::ConstantInt *CodeGenModule::CreateCrossDsoCfiTypeId(llvm::Metadata *MD) {
  llvm::MDString *MDS = dyn_cast<llvm::MDString>(MD);
  if (!MDS) return nullptr;
 
  return llvm::ConstantInt::get(Int64Ty, llvm::MD5Hash(MDS->getString()));
}
 
llvm::ConstantInt *CodeGenModule::CreateKCFITypeId(QualType T) {
  if (auto *FnType = T->getAs<FunctionProtoType>())
    T = getContext().getFunctionType(
        FnType->getReturnType(), FnType->getParamTypes(),
        FnType->getExtProtoInfo().withExceptionSpec(EST_None));
 
  std::string OutName;
  llvm::raw_string_ostream Out(OutName);
  getCXXABI().getMangleContext().mangleTypeName(
      T, Out, getCodeGenOpts().SanitizeCfiICallNormalizeIntegers);
 
  if (getCodeGenOpts().SanitizeCfiICallNormalizeIntegers)
    Out << ".normalized";
 
  return llvm::ConstantInt::get(Int32Ty,
                                static_cast<uint32_t>(llvm::xxHash64(OutName)));
}
 
void CodeGenModule::SetLLVMFunctionAttributes(GlobalDecl GD,
                                              const CGFunctionInfo &Info,
                                              llvm::Function *F, bool IsThunk) {
  unsigned CallingConv;
  llvm::AttributeList PAL;
  ConstructAttributeList(F->getName(), Info, GD, PAL, CallingConv,
                         /*AttrOnCallSite=*/false, IsThunk);
  F->setAttributes(PAL);
  F->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv));
}
 
static void removeImageAccessQualifier(std::string& TyName) {
  std::string ReadOnlyQual("__read_only");
  std::string::size_type ReadOnlyPos = TyName.find(ReadOnlyQual);
  if (ReadOnlyPos != std::string::npos)
    // "+ 1" for the space after access qualifier.
    TyName.erase(ReadOnlyPos, ReadOnlyQual.size() + 1);
  else {
    std::string WriteOnlyQual("__write_only");
    std::string::size_type WriteOnlyPos = TyName.find(WriteOnlyQual);
    if (WriteOnlyPos != std::string::npos)
      TyName.erase(WriteOnlyPos, WriteOnlyQual.size() + 1);
    else {
      std::string ReadWriteQual("__read_write");
      std::string::size_type ReadWritePos = TyName.find(ReadWriteQual);
      if (ReadWritePos != std::string::npos)
        TyName.erase(ReadWritePos, ReadWriteQual.size() + 1);
    }
  }
}
 
// Returns the address space id that should be produced to the
// kernel_arg_addr_space metadata. This is always fixed to the ids
// as specified in the SPIR 2.0 specification in order to differentiate
// for example in clGetKernelArgInfo() implementation between the address
// spaces with targets without unique mapping to the OpenCL address spaces
// (basically all single AS CPUs).
static unsigned ArgInfoAddressSpace(LangAS AS) {
  switch (AS) {
  case LangAS::opencl_global:
    return 1;
  case LangAS::opencl_constant:
    return 2;
  case LangAS::opencl_local:
    return 3;
  case LangAS::opencl_generic:
    return 4; // Not in SPIR 2.0 specs.
  case LangAS::opencl_global_device:
    return 5;
  case LangAS::opencl_global_host:
    return 6;
  default:
    return 0; // Assume private.
  }
}
 
void CodeGenModule::GenKernelArgMetadata(llvm::Function *Fn,
                                         const FunctionDecl *FD,
                                         CodeGenFunction *CGF) {
  assert(((FD && CGF) || (!FD && !CGF)) &&
         "Incorrect use - FD and CGF should either be both null or not!");
  // Create MDNodes that represent the kernel arg metadata.
  // Each MDNode is a list in the form of "key", N number of values which is
  // the same number of values as their are kernel arguments.
 
  const PrintingPolicy &Policy = Context.getPrintingPolicy();
 
  // MDNode for the kernel argument address space qualifiers.
  SmallVector<llvm::Metadata *, 8> addressQuals;
 
  // MDNode for the kernel argument access qualifiers (images only).
  SmallVector<llvm::Metadata *, 8> accessQuals;
 
  // MDNode for the kernel argument type names.
  SmallVector<llvm::Metadata *, 8> argTypeNames;
 
  // MDNode for the kernel argument base type names.
  SmallVector<llvm::Metadata *, 8> argBaseTypeNames;
 
  // MDNode for the kernel argument type qualifiers.
  SmallVector<llvm::Metadata *, 8> argTypeQuals;
 
  // MDNode for the kernel argument names.
  SmallVector<llvm::Metadata *, 8> argNames;
 
  if (FD && CGF)
    for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) {
      const ParmVarDecl *parm = FD->getParamDecl(i);
      // Get argument name.
      argNames.push_back(llvm::MDString::get(VMContext, parm->getName()));
 
      if (!getLangOpts().OpenCL)
        continue;
      QualType ty = parm->getType();
      std::string typeQuals;
 
      // Get image and pipe access qualifier:
      if (ty->isImageType() || ty->isPipeType()) {
        const Decl *PDecl = parm;
        if (const auto *TD = ty->getAs<TypedefType>())
          PDecl = TD->getDecl();
        const OpenCLAccessAttr *A = PDecl->getAttr<OpenCLAccessAttr>();
        if (A && A->isWriteOnly())
          accessQuals.push_back(llvm::MDString::get(VMContext, "write_only"));
        else if (A && A->isReadWrite())
          accessQuals.push_back(llvm::MDString::get(VMContext, "read_write"));
        else
          accessQuals.push_back(llvm::MDString::get(VMContext, "read_only"));
      } else
        accessQuals.push_back(llvm::MDString::get(VMContext, "none"));
 
      auto getTypeSpelling = [&](QualType Ty) {
        auto typeName = Ty.getUnqualifiedType().getAsString(Policy);
 
        if (Ty.isCanonical()) {
          StringRef typeNameRef = typeName;
          // Turn "unsigned type" to "utype"
          if (typeNameRef.consume_front("unsigned "))
            return std::string("u") + typeNameRef.str();
          if (typeNameRef.consume_front("signed "))
            return typeNameRef.str();
        }
 
        return typeName;
      };
 
      if (ty->isPointerType()) {
        QualType pointeeTy = ty->getPointeeType();
 
        // Get address qualifier.
        addressQuals.push_back(
            llvm::ConstantAsMetadata::get(CGF->Builder.getInt32(
                ArgInfoAddressSpace(pointeeTy.getAddressSpace()))));
 
        // Get argument type name.
        std::string typeName = getTypeSpelling(pointeeTy) + "*";
        std::string baseTypeName =
            getTypeSpelling(pointeeTy.getCanonicalType()) + "*";
        argTypeNames.push_back(llvm::MDString::get(VMContext, typeName));
        argBaseTypeNames.push_back(
            llvm::MDString::get(VMContext, baseTypeName));
 
        // Get argument type qualifiers:
        if (ty.isRestrictQualified())
          typeQuals = "restrict";
        if (pointeeTy.isConstQualified() ||
            (pointeeTy.getAddressSpace() == LangAS::opencl_constant))
          typeQuals += typeQuals.empty() ? "const" : " const";
        if (pointeeTy.isVolatileQualified())
          typeQuals += typeQuals.empty() ? "volatile" : " volatile";
      } else {
        uint32_t AddrSpc = 0;
        bool isPipe = ty->isPipeType();
        if (ty->isImageType() || isPipe)
          AddrSpc = ArgInfoAddressSpace(LangAS::opencl_global);
 
        addressQuals.push_back(
            llvm::ConstantAsMetadata::get(CGF->Builder.getInt32(AddrSpc)));
 
        // Get argument type name.
        ty = isPipe ? ty->castAs<PipeType>()->getElementType() : ty;
        std::string typeName = getTypeSpelling(ty);
        std::string baseTypeName = getTypeSpelling(ty.getCanonicalType());
 
        // Remove access qualifiers on images
        // (as they are inseparable from type in clang implementation,
        // but OpenCL spec provides a special query to get access qualifier
        // via clGetKernelArgInfo with CL_KERNEL_ARG_ACCESS_QUALIFIER):
        if (ty->isImageType()) {
          removeImageAccessQualifier(typeName);
          removeImageAccessQualifier(baseTypeName);
        }
 
        argTypeNames.push_back(llvm::MDString::get(VMContext, typeName));
        argBaseTypeNames.push_back(
            llvm::MDString::get(VMContext, baseTypeName));
 
        if (isPipe)
          typeQuals = "pipe";
      }
      argTypeQuals.push_back(llvm::MDString::get(VMContext, typeQuals));
    }
 
  if (getLangOpts().OpenCL) {
    Fn->setMetadata("kernel_arg_addr_space",
                    llvm::MDNode::get(VMContext, addressQuals));
    Fn->setMetadata("kernel_arg_access_qual",
                    llvm::MDNode::get(VMContext, accessQuals));
    Fn->setMetadata("kernel_arg_type",
                    llvm::MDNode::get(VMContext, argTypeNames));
    Fn->setMetadata("kernel_arg_base_type",
                    llvm::MDNode::get(VMContext, argBaseTypeNames));
    Fn->setMetadata("kernel_arg_type_qual",
                    llvm::MDNode::get(VMContext, argTypeQuals));
  }
  if (getCodeGenOpts().EmitOpenCLArgMetadata ||
      getCodeGenOpts().HIPSaveKernelArgName)
    Fn->setMetadata("kernel_arg_name",
                    llvm::MDNode::get(VMContext, argNames));
}
 
/// Determines whether the language options require us to model
/// unwind exceptions.  We treat -fexceptions as mandating this
/// except under the fragile ObjC ABI with only ObjC exceptions
/// enabled.  This means, for example, that C with -fexceptions
/// enables this.
static bool hasUnwindExceptions(const LangOptions &LangOpts) {
  // If exceptions are completely disabled, obviously this is false.
  if (!LangOpts.Exceptions) return false;
 
  // If C++ exceptions are enabled, this is true.
  if (LangOpts.CXXExceptions) return true;
 
  // If ObjC exceptions are enabled, this depends on the ABI.
  if (LangOpts.ObjCExceptions) {
    return LangOpts.ObjCRuntime.hasUnwindExceptions();
  }
 
  return true;
}
 
static bool requiresMemberFunctionPointerTypeMetadata(CodeGenModule &CGM,
                                                      const CXXMethodDecl *MD) {
  // Check that the type metadata can ever actually be used by a call.
  if (!CGM.getCodeGenOpts().LTOUnit ||
      !CGM.HasHiddenLTOVisibility(MD->getParent()))
    return false;
 
  // Only functions whose address can be taken with a member function pointer
  // need this sort of type metadata.
  return !MD->isStatic() && !MD->isVirtual() && !isa<CXXConstructorDecl>(MD) &&
         !isa<CXXDestructorDecl>(MD);
}
 
SmallVector<const CXXRecordDecl *, 0>
CodeGenModule::getMostBaseClasses(const CXXRecordDecl *RD) {
  llvm::SetVector<const CXXRecordDecl *> MostBases;
 
  std::function<void (const CXXRecordDecl *)> CollectMostBases;
  CollectMostBases = [&](const CXXRecordDecl *RD) {
    if (RD->getNumBases() == 0)
      MostBases.insert(RD);
    for (const CXXBaseSpecifier &B : RD->bases())
      CollectMostBases(B.getType()->getAsCXXRecordDecl());
  };
  CollectMostBases(RD);
  return MostBases.takeVector();
}
 
void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
                                                           llvm::Function *F) {
  llvm::AttrBuilder B(F->getContext());
 
  if ((!D || !D->hasAttr<NoUwtableAttr>()) && CodeGenOpts.UnwindTables)
    B.addUWTableAttr(llvm::UWTableKind(CodeGenOpts.UnwindTables));
 
  if (CodeGenOpts.StackClashProtector)
    B.addAttribute("probe-stack", "inline-asm");
 
  if (!hasUnwindExceptions(LangOpts))
    B.addAttribute(llvm::Attribute::NoUnwind);
 
  if (D && D->hasAttr<NoStackProtectorAttr>())
    ; // Do nothing.
  else if (D && D->hasAttr<StrictGuardStackCheckAttr>() &&
           LangOpts.getStackProtector() == LangOptions::SSPOn)
    B.addAttribute(llvm::Attribute::StackProtectStrong);
  else if (LangOpts.getStackProtector() == LangOptions::SSPOn)
    B.addAttribute(llvm::Attribute::StackProtect);
  else if (LangOpts.getStackProtector() == LangOptions::SSPStrong)
    B.addAttribute(llvm::Attribute::StackProtectStrong);
  else if (LangOpts.getStackProtector() == LangOptions::SSPReq)
    B.addAttribute(llvm::Attribute::StackProtectReq);
 
  if (!D) {
    // If we don't have a declaration to control inlining, the function isn't
    // explicitly marked as alwaysinline for semantic reasons, and inlining is
    // disabled, mark the function as noinline.
    if (!F->hasFnAttribute(llvm::Attribute::AlwaysInline) &&
        CodeGenOpts.getInlining() == CodeGenOptions::OnlyAlwaysInlining)
      B.addAttribute(llvm::Attribute::NoInline);
 
    F->addFnAttrs(B);
    return;
  }
 
  // Handle SME attributes that apply to function definitions,
  // rather than to function prototypes.
  if (D->hasAttr<ArmLocallyStreamingAttr>())
    B.addAttribute("aarch64_pstate_sm_body");
 
  if (D->hasAttr<ArmNewZAAttr>())
    B.addAttribute("aarch64_pstate_za_new");
 
  // Track whether we need to add the optnone LLVM attribute,
  // starting with the default for this optimization level.
  bool ShouldAddOptNone =
      !CodeGenOpts.DisableO0ImplyOptNone && CodeGenOpts.OptimizationLevel == 0;
  // We can't add optnone in the following cases, it won't pass the verifier.
  ShouldAddOptNone &= !D->hasAttr<MinSizeAttr>();
  ShouldAddOptNone &= !D->hasAttr<AlwaysInlineAttr>();
 
  // Add optnone, but do so only if the function isn't always_inline.
  if ((ShouldAddOptNone || D->hasAttr<OptimizeNoneAttr>()) &&
      !F->hasFnAttribute(llvm::Attribute::AlwaysInline)) {
    B.addAttribute(llvm::Attribute::OptimizeNone);
 
    // OptimizeNone implies noinline; we should not be inlining such functions.
    B.addAttribute(llvm::Attribute::NoInline);
 
    // We still need to handle naked functions even though optnone subsumes
    // much of their semantics.
    if (D->hasAttr<NakedAttr>())
      B.addAttribute(llvm::Attribute::Naked);
 
    // OptimizeNone wins over OptimizeForSize and MinSize.
    F->removeFnAttr(llvm::Attribute::OptimizeForSize);
    F->removeFnAttr(llvm::Attribute::MinSize);
  } else if (D->hasAttr<NakedAttr>()) {
    // Naked implies noinline: we should not be inlining such functions.
    B.addAttribute(llvm::Attribute::Naked);
    B.addAttribute(llvm::Attribute::NoInline);
  } else if (D->hasAttr<NoDuplicateAttr>()) {
    B.addAttribute(llvm::Attribute::NoDuplicate);
  } else if (D->hasAttr<NoInlineAttr>() && !F->hasFnAttribute(llvm::Attribute::AlwaysInline)) {
    // Add noinline if the function isn't always_inline.
    B.addAttribute(llvm::Attribute::NoInline);
  } else if (D->hasAttr<AlwaysInlineAttr>() &&
             !F->hasFnAttribute(llvm::Attribute::NoInline)) {
    // (noinline wins over always_inline, and we can't specify both in IR)
    B.addAttribute(llvm::Attribute::AlwaysInline);
  } else if (CodeGenOpts.getInlining() == CodeGenOptions::OnlyAlwaysInlining) {
    // If we're not inlining, then force everything that isn't always_inline to
    // carry an explicit noinline attribute.
    if (!F->hasFnAttribute(llvm::Attribute::AlwaysInline))
      B.addAttribute(llvm::Attribute::NoInline);
  } else {
    // Otherwise, propagate the inline hint attribute and potentially use its
    // absence to mark things as noinline.
    if (auto *FD = dyn_cast<FunctionDecl>(D)) {
      // Search function and template pattern redeclarations for inline.
      auto CheckForInline = [](const FunctionDecl *FD) {
        auto CheckRedeclForInline = [](const FunctionDecl *Redecl) {
          return Redecl->isInlineSpecified();
        };
        if (any_of(FD->redecls(), CheckRedeclForInline))
          return true;
        const FunctionDecl *Pattern = FD->getTemplateInstantiationPattern();
        if (!Pattern)
          return false;
        return any_of(Pattern->redecls(), CheckRedeclForInline);
      };
      if (CheckForInline(FD)) {
        B.addAttribute(llvm::Attribute::InlineHint);
      } else if (CodeGenOpts.getInlining() ==
                     CodeGenOptions::OnlyHintInlining &&
                 !FD->isInlined() &&
                 !F->hasFnAttribute(llvm::Attribute::AlwaysInline)) {
        B.addAttribute(llvm::Attribute::NoInline);
      }
    }
  }
 
  // Add other optimization related attributes if we are optimizing this
  // function.
  if (!D->hasAttr<OptimizeNoneAttr>()) {
    if (D->hasAttr<ColdAttr>()) {
      if (!ShouldAddOptNone)
        B.addAttribute(llvm::Attribute::OptimizeForSize);
      B.addAttribute(llvm::Attribute::Cold);
    }
    if (D->hasAttr<HotAttr>())
      B.addAttribute(llvm::Attribute::Hot);
    if (D->hasAttr<MinSizeAttr>())
      B.addAttribute(llvm::Attribute::MinSize);
  }
 
  F->addFnAttrs(B);
 
  unsigned alignment = D->getMaxAlignment() / Context.getCharWidth();
  if (alignment)
    F->setAlignment(llvm::Align(alignment));
 
  if (!D->hasAttr<AlignedAttr>())
    if (LangOpts.FunctionAlignment)
      F->setAlignment(llvm::Align(1ull << LangOpts.FunctionAlignment));
 
  // Some C++ ABIs require 2-byte alignment for member functions, in order to
  // reserve a bit for differentiating between virtual and non-virtual member
  // functions. If the current target's C++ ABI requires this and this is a
  // member function, set its alignment accordingly.
  if (getTarget().getCXXABI().areMemberFunctionsAligned()) {
    if (isa<CXXMethodDecl>(D) && F->getPointerAlignment(getDataLayout()) < 2)
      F->setAlignment(std::max(llvm::Align(2), F->getAlign().valueOrOne()));
  }
 
  // In the cross-dso CFI mode with canonical jump tables, we want !type
  // attributes on definitions only.
  if (CodeGenOpts.SanitizeCfiCrossDso &&
      CodeGenOpts.SanitizeCfiCanonicalJumpTables) {
    if (auto *FD = dyn_cast<FunctionDecl>(D)) {
      // Skip available_externally functions. They won't be codegen'ed in the
      // current module anyway.
      if (getContext().GetGVALinkageForFunction(FD) != GVA_AvailableExternally)
        CreateFunctionTypeMetadataForIcall(FD, F);
    }
  }
 
  // Emit type metadata on member functions for member function pointer checks.
  // These are only ever necessary on definitions; we're guaranteed that the
  // definition will be present in the LTO unit as a result of LTO visibility.
  auto *MD = dyn_cast<CXXMethodDecl>(D);
  if (MD && requiresMemberFunctionPointerTypeMetadata(*this, MD)) {
    for (const CXXRecordDecl *Base : getMostBaseClasses(MD->getParent())) {
      llvm::Metadata *Id =
          CreateMetadataIdentifierForType(Context.getMemberPointerType(
              MD->getType(), Context.getRecordType(Base).getTypePtr()));
      F->addTypeMetadata(0, Id);
    }
  }
}
 
void CodeGenModule::SetCommonAttributes(GlobalDecl GD, llvm::GlobalValue *GV) {
  const Decl *D = GD.getDecl();
  if (isa_and_nonnull<NamedDecl>(D))
    setGVProperties(GV, GD);
  else
    GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
 
  if (D && D->hasAttr<UsedAttr>())
    addUsedOrCompilerUsedGlobal(GV);
 
  if (const auto *VD = dyn_cast_if_present<VarDecl>(D);
      VD &&
      ((CodeGenOpts.KeepPersistentStorageVariables &&
        (VD->getStorageDuration() == SD_Static ||
         VD->getStorageDuration() == SD_Thread)) ||
       (CodeGenOpts.KeepStaticConsts && VD->getStorageDuration() == SD_Static &&
        VD->getType().isConstQualified())))
    addUsedOrCompilerUsedGlobal(GV);
}
 
bool CodeGenModule::GetCPUAndFeaturesAttributes(GlobalDecl GD,
                                                llvm::AttrBuilder &Attrs,
                                                bool SetTargetFeatures) {
  // Add target-cpu and target-features attributes to functions. If
  // we have a decl for the function and it has a target attribute then
  // parse that and add it to the feature set.
  StringRef TargetCPU = getTarget().getTargetOpts().CPU;
  StringRef TuneCPU = getTarget().getTargetOpts().TuneCPU;
  std::vector<std::string> Features;
  const auto *FD = dyn_cast_or_null<FunctionDecl>(GD.getDecl());
  FD = FD ? FD->getMostRecentDecl() : FD;
  const auto *TD = FD ? FD->getAttr<TargetAttr>() : nullptr;
  const auto *TV = FD ? FD->getAttr<TargetVersionAttr>() : nullptr;
  assert((!TD || !TV) && "both target_version and target specified");
  const auto *SD = FD ? FD->getAttr<CPUSpecificAttr>() : nullptr;
  const auto *TC = FD ? FD->getAttr<TargetClonesAttr>() : nullptr;
  bool AddedAttr = false;
  if (TD || TV || SD || TC) {
    llvm::StringMap<bool> FeatureMap;
    getContext().getFunctionFeatureMap(FeatureMap, GD);
 
    // Produce the canonical string for this set of features.
    for (const llvm::StringMap<bool>::value_type &Entry : FeatureMap)
      Features.push_back((Entry.getValue() ? "+" : "-") + Entry.getKey().str());
 
    // Now add the target-cpu and target-features to the function.
    // While we populated the feature map above, we still need to
    // get and parse the target attribute so we can get the cpu for
    // the function.
    if (TD) {
      ParsedTargetAttr ParsedAttr =
          Target.parseTargetAttr(TD->getFeaturesStr());
      if (!ParsedAttr.CPU.empty() &&
          getTarget().isValidCPUName(ParsedAttr.CPU)) {
        TargetCPU = ParsedAttr.CPU;
        TuneCPU = ""; // Clear the tune CPU.
      }
      if (!ParsedAttr.Tune.empty() &&
          getTarget().isValidCPUName(ParsedAttr.Tune))
        TuneCPU = ParsedAttr.Tune;
    }
 
    if (SD) {
      // Apply the given CPU name as the 'tune-cpu' so that the optimizer can
      // favor this processor.
      TuneCPU = SD->getCPUName(GD.getMultiVersionIndex())->getName();
    }
  } else {
    // Otherwise just add the existing target cpu and target features to the
    // function.
    Features = getTarget().getTargetOpts().Features;
  }
 
  if (!TargetCPU.empty()) {
    Attrs.addAttribute("target-cpu", TargetCPU);
    AddedAttr = true;
  }
  if (!TuneCPU.empty()) {
    Attrs.addAttribute("tune-cpu", TuneCPU);
    AddedAttr = true;
  }
  if (!Features.empty() && SetTargetFeatures) {
    llvm::erase_if(Features, [&](const std::string& F) {
       return getTarget().isReadOnlyFeature(F.substr(1));
    });
    llvm::sort(Features);
    Attrs.addAttribute("target-features", llvm::join(Features, ","));
    AddedAttr = true;
  }
 
  return AddedAttr;
}
 
void CodeGenModule::setNonAliasAttributes(GlobalDecl GD,
                                          llvm::GlobalObject *GO) {
  const Decl *D = GD.getDecl();
  SetCommonAttributes(GD, GO);
 
  if (D) {
    if (auto *GV = dyn_cast<llvm::GlobalVariable>(GO)) {
      if (D->hasAttr<RetainAttr>())
        addUsedGlobal(GV);
      if (auto *SA = D->getAttr<PragmaClangBSSSectionAttr>())
        GV->addAttribute("bss-section", SA->getName());
      if (auto *SA = D->getAttr<PragmaClangDataSectionAttr>())
        GV->addAttribute("data-section", SA->getName());
      if (auto *SA = D->getAttr<PragmaClangRodataSectionAttr>())
        GV->addAttribute("rodata-section", SA->getName());
      if (auto *SA = D->getAttr<PragmaClangRelroSectionAttr>())
        GV->addAttribute("relro-section", SA->getName());
    }
 
    if (auto *F = dyn_cast<llvm::Function>(GO)) {
      if (D->hasAttr<RetainAttr>())
        addUsedGlobal(F);
      if (auto *SA = D->getAttr<PragmaClangTextSectionAttr>())
        if (!D->getAttr<SectionAttr>())
          F->addFnAttr("implicit-section-name", SA->getName());
 
      llvm::AttrBuilder Attrs(F->getContext());
      if (GetCPUAndFeaturesAttributes(GD, Attrs)) {
        // We know that GetCPUAndFeaturesAttributes will always have the
        // newest set, since it has the newest possible FunctionDecl, so the
        // new ones should replace the old.
        llvm::AttributeMask RemoveAttrs;
        RemoveAttrs.addAttribute("target-cpu");
        RemoveAttrs.addAttribute("target-features");
        RemoveAttrs.addAttribute("tune-cpu");
        F->removeFnAttrs(RemoveAttrs);
        F->addFnAttrs(Attrs);
      }
    }
 
    if (const auto *CSA = D->getAttr<CodeSegAttr>())
      GO->setSection(CSA->getName());
    else if (const auto *SA = D->getAttr<SectionAttr>())
      GO->setSection(SA->getName());
  }
 
  getTargetCodeGenInfo().setTargetAttributes(D, GO, *this);
}
 
void CodeGenModule::SetInternalFunctionAttributes(GlobalDecl GD,
                                                  llvm::Function *F,
                                                  const CGFunctionInfo &FI) {
  const Decl *D = GD.getDecl();
  SetLLVMFunctionAttributes(GD, FI, F, /*IsThunk=*/false);
  SetLLVMFunctionAttributesForDefinition(D, F);
 
  F->setLinkage(llvm::Function::InternalLinkage);
 
  setNonAliasAttributes(GD, F);
}
 
static void setLinkageForGV(llvm::GlobalValue *GV, const NamedDecl *ND) {
  // Set linkage and visibility in case we never see a definition.
  LinkageInfo LV = ND->getLinkageAndVisibility();
  // Don't set internal linkage on declarations.
  // "extern_weak" is overloaded in LLVM; we probably should have
  // separate linkage types for this.
  if (isExternallyVisible(LV.getLinkage()) &&
      (ND->hasAttr<WeakAttr>() || ND->isWeakImported()))
    GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
}
 
void CodeGenModule::CreateFunctionTypeMetadataForIcall(const FunctionDecl *FD,
                                                       llvm::Function *F) {
  // Only if we are checking indirect calls.
  if (!LangOpts.Sanitize.has(SanitizerKind::CFIICall))
    return;
 
  // Non-static class methods are handled via vtable or member function pointer
  // checks elsewhere.
  if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic())
    return;
 
  llvm::Metadata *MD = CreateMetadataIdentifierForType(FD->getType());
  F->addTypeMetadata(0, MD);
  F->addTypeMetadata(0, CreateMetadataIdentifierGeneralized(FD->getType()));
 
  // Emit a hash-based bit set entry for cross-DSO calls.
  if (CodeGenOpts.SanitizeCfiCrossDso)
    if (auto CrossDsoTypeId = CreateCrossDsoCfiTypeId(MD))
      F->addTypeMetadata(0, llvm::ConstantAsMetadata::get(CrossDsoTypeId));
}
 
void CodeGenModule::setKCFIType(const FunctionDecl *FD, llvm::Function *F) {
  llvm::LLVMContext &Ctx = F->getContext();
  llvm::MDBuilder MDB(Ctx);
  F->setMetadata(llvm::LLVMContext::MD_kcfi_type,
                 llvm::MDNode::get(
                     Ctx, MDB.createConstant(CreateKCFITypeId(FD->getType()))));
}
 
static bool allowKCFIIdentifier(StringRef Name) {
  // KCFI type identifier constants are only necessary for external assembly
  // functions, which means it's safe to skip unusual names. Subset of
  // MCAsmInfo::isAcceptableChar() and MCAsmInfoXCOFF::isAcceptableChar().
  return llvm::all_of(Name, [](const char &C) {
    return llvm::isAlnum(C) || C == '_' || C == '.';
  });
}
 
void CodeGenModule::finalizeKCFITypes() {
  llvm::Module &M = getModule();
  for (auto &F : M.functions()) {
    // Remove KCFI type metadata from non-address-taken local functions.
    bool AddressTaken = F.hasAddressTaken();
    if (!AddressTaken && F.hasLocalLinkage())
      F.eraseMetadata(llvm::LLVMContext::MD_kcfi_type);
 
    // Generate a constant with the expected KCFI type identifier for all
    // address-taken function declarations to support annotating indirectly
    // called assembly functions.
    if (!AddressTaken || !F.isDeclaration())
      continue;
 
    const llvm::ConstantInt *Type;
    if (const llvm::MDNode *MD = F.getMetadata(llvm::LLVMContext::MD_kcfi_type))
      Type = llvm::mdconst::extract<llvm::ConstantInt>(MD->getOperand(0));
    else
      continue;
 
    StringRef Name = F.getName();
    if (!allowKCFIIdentifier(Name))
      continue;
 
    std::string Asm = (".weak __kcfi_typeid_" + Name + "\n.set __kcfi_typeid_" +
                       Name + ", " + Twine(Type->getZExtValue()) + "\n")
                          .str();
    M.appendModuleInlineAsm(Asm);
  }
}
 
void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, llvm::Function *F,
                                          bool IsIncompleteFunction,
                                          bool IsThunk) {
 
  if (llvm::Intrinsic::ID IID = F->getIntrinsicID()) {
    // If this is an intrinsic function, set the function's attributes
    // to the intrinsic's attributes.
    F->setAttributes(llvm::Intrinsic::getAttributes(getLLVMContext(), IID));
    return;
  }
 
  const auto *FD = cast<FunctionDecl>(GD.getDecl());
 
  if (!IsIncompleteFunction)
    SetLLVMFunctionAttributes(GD, getTypes().arrangeGlobalDeclaration(GD), F,
                              IsThunk);
 
  // Add the Returned attribute for "this", except for iOS 5 and earlier
  // where substantial code, including the libstdc++ dylib, was compiled with
  // GCC and does not actually return "this".
  if (!IsThunk && getCXXABI().HasThisReturn(GD) &&
      !(getTriple().isiOS() && getTriple().isOSVersionLT(6))) {
    assert(!F->arg_empty() &&
           F->arg_begin()->getType()
             ->canLosslesslyBitCastTo(F->getReturnType()) &&
           "unexpected this return");
    F->addParamAttr(0, llvm::Attribute::Returned);
  }
 
  // Only a few attributes are set on declarations; these may later be
  // overridden by a definition.
 
  setLinkageForGV(F, FD);
  setGVProperties(F, FD);
 
  // Setup target-specific attributes.
  if (!IsIncompleteFunction && F->isDeclaration())
    getTargetCodeGenInfo().setTargetAttributes(FD, F, *this);
 
  if (const auto *CSA = FD->getAttr<CodeSegAttr>())
    F->setSection(CSA->getName());
  else if (const auto *SA = FD->getAttr<SectionAttr>())
     F->setSection(SA->getName());
 
  if (const auto *EA = FD->getAttr<ErrorAttr>()) {
    if (EA->isError())
      F->addFnAttr("dontcall-error", EA->getUserDiagnostic());
    else if (EA->isWarning())
      F->addFnAttr("dontcall-warn", EA->getUserDiagnostic());
  }
 
  // If we plan on emitting this inline builtin, we can't treat it as a builtin.
  if (FD->isInlineBuiltinDeclaration()) {
    const FunctionDecl *FDBody;
    bool HasBody = FD->hasBody(FDBody);
    (void)HasBody;
    assert(HasBody && "Inline builtin declarations should always have an "
                      "available body!");
    if (shouldEmitFunction(FDBody))
      F->addFnAttr(llvm::Attribute::NoBuiltin);
  }
 
  if (FD->isReplaceableGlobalAllocationFunction()) {
    // A replaceable global allocation function does not act like a builtin by
    // default, only if it is invoked by a new-expression or delete-expression.
    F->addFnAttr(llvm::Attribute::NoBuiltin);
  }
 
  if (isa<CXXConstructorDecl>(FD) || isa<CXXDestructorDecl>(FD))
    F->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
  else if (const auto *MD = dyn_cast<CXXMethodDecl>(FD))
    if (MD->isVirtual())
      F->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
 
  // Don't emit entries for function declarations in the cross-DSO mode. This
  // is handled with better precision by the receiving DSO. But if jump tables
  // are non-canonical then we need type metadata in order to produce the local
  // jump table.
  if (!CodeGenOpts.SanitizeCfiCrossDso ||
      !CodeGenOpts.SanitizeCfiCanonicalJumpTables)
    CreateFunctionTypeMetadataForIcall(FD, F);
 
  if (LangOpts.Sanitize.has(SanitizerKind::KCFI))
    setKCFIType(FD, F);
 
  if (getLangOpts().OpenMP && FD->hasAttr<OMPDeclareSimdDeclAttr>())
    getOpenMPRuntime().emitDeclareSimdFunction(FD, F);
 
  if (CodeGenOpts.InlineMaxStackSize != UINT_MAX)
    F->addFnAttr("inline-max-stacksize", llvm::utostr(CodeGenOpts.InlineMaxStackSize));
 
  if (const auto *CB = FD->getAttr<CallbackAttr>()) {
    // Annotate the callback behavior as metadata:
    //  - The callback callee (as argument number).
    //  - The callback payloads (as argument numbers).
    llvm::LLVMContext &Ctx = F->getContext();
    llvm::MDBuilder MDB(Ctx);
 
    // The payload indices are all but the first one in the encoding. The first
    // identifies the callback callee.
    int CalleeIdx = *CB->encoding_begin();
    ArrayRef<int> PayloadIndices(CB->encoding_begin() + 1, CB->encoding_end());
    F->addMetadata(llvm::LLVMContext::MD_callback,
                   *llvm::MDNode::get(Ctx, {MDB.createCallbackEncoding(
                                               CalleeIdx, PayloadIndices,
                                               /* VarArgsArePassed */ false)}));
  }
}
 
void CodeGenModule::addUsedGlobal(llvm::GlobalValue *GV) {
  assert((isa<llvm::Function>(GV) || !GV->isDeclaration()) &&
         "Only globals with definition can force usage.");
  LLVMUsed.emplace_back(GV);
}
 
void CodeGenModule::addCompilerUsedGlobal(llvm::GlobalValue *GV) {
  assert(!GV->isDeclaration() &&
         "Only globals with definition can force usage.");
  LLVMCompilerUsed.emplace_back(GV);
}
 
void CodeGenModule::addUsedOrCompilerUsedGlobal(llvm::GlobalValue *GV) {
  assert((isa<llvm::Function>(GV) || !GV->isDeclaration()) &&
         "Only globals with definition can force usage.");
  if (getTriple().isOSBinFormatELF())
    LLVMCompilerUsed.emplace_back(GV);
  else
    LLVMUsed.emplace_back(GV);
}
 
static void emitUsed(CodeGenModule &CGM, StringRef Name,
                     std::vector<llvm::WeakTrackingVH> &List) {
  // Don't create llvm.used if there is no need.
  if (List.empty())
    return;
 
  // Convert List to what ConstantArray needs.
  SmallVector<llvm::Constant*, 8> UsedArray;
  UsedArray.resize(List.size());
  for (unsigned i = 0, e = List.size(); i != e; ++i) {
    UsedArray[i] =
        llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(
            cast<llvm::Constant>(&*List[i]), CGM.Int8PtrTy);
  }
 
  if (UsedArray.empty())
    return;
  llvm::ArrayType *ATy = llvm::ArrayType::get(CGM.Int8PtrTy, UsedArray.size());
 
  auto *GV = new llvm::GlobalVariable(
      CGM.getModule(), ATy, false, llvm::GlobalValue::AppendingLinkage,
      llvm::ConstantArray::get(ATy, UsedArray), Name);
 
  GV->setSection("llvm.metadata");
}
 
void CodeGenModule::emitLLVMUsed() {
  emitUsed(*this, "llvm.used", LLVMUsed);
  emitUsed(*this, "llvm.compiler.used", LLVMCompilerUsed);
}
 
void CodeGenModule::AppendLinkerOptions(StringRef Opts) {
  auto *MDOpts = llvm::MDString::get(getLLVMContext(), Opts);
  LinkerOptionsMetadata.push_back(llvm::MDNode::get(getLLVMContext(), MDOpts));
}
 
void CodeGenModule::AddDetectMismatch(StringRef Name, StringRef Value) {
  llvm::SmallString<32> Opt;
  getTargetCodeGenInfo().getDetectMismatchOption(Name, Value, Opt);
  if (Opt.empty())
    return;
  auto *MDOpts = llvm::MDString::get(getLLVMContext(), Opt);
  LinkerOptionsMetadata.push_back(llvm::MDNode::get(getLLVMContext(), MDOpts));
}
 
void CodeGenModule::AddDependentLib(StringRef Lib) {
  auto &C = getLLVMContext();
  if (getTarget().getTriple().isOSBinFormatELF()) {
      ELFDependentLibraries.push_back(
        llvm::MDNode::get(C, llvm::MDString::get(C, Lib)));
    return;
  }
 
  llvm::SmallString<24> Opt;
  getTargetCodeGenInfo().getDependentLibraryOption(Lib, Opt);
  auto *MDOpts = llvm::MDString::get(getLLVMContext(), Opt);
  LinkerOptionsMetadata.push_back(llvm::MDNode::get(C, MDOpts));
}
 
/// Add link options implied by the given module, including modules
/// it depends on, using a postorder walk.
static void addLinkOptionsPostorder(CodeGenModule &CGM, Module *Mod,
                                    SmallVectorImpl<llvm::MDNode *> &Metadata,
                                    llvm::SmallPtrSet<Module *, 16> &Visited) {
  // Import this module's parent.
  if (Mod->Parent && Visited.insert(Mod->Parent).second) {
    addLinkOptionsPostorder(CGM, Mod->Parent, Metadata, Visited);
  }
 
  // Import this module's dependencies.
  for (Module *Import : llvm::reverse(Mod->Imports)) {
    if (Visited.insert(Import).second)
      addLinkOptionsPostorder(CGM, Import, Metadata, Visited);
  }
 
  // Add linker options to link against the libraries/frameworks
  // described by this module.
  llvm::LLVMContext &Context = CGM.getLLVMContext();
  bool IsELF = CGM.getTarget().getTriple().isOSBinFormatELF();
 
  // For modules that use export_as for linking, use that module
  // name instead.
  if (Mod->UseExportAsModuleLinkName)
    return;
 
  for (const Module::LinkLibrary &LL : llvm::reverse(Mod->LinkLibraries)) {
    // Link against a framework.  Frameworks are currently Darwin only, so we
    // don't to ask TargetCodeGenInfo for the spelling of the linker option.
    if (LL.IsFramework) {
      llvm::Metadata *Args[2] = {llvm::MDString::get(Context, "-framework"),
                                 llvm::MDString::get(Context, LL.Library)};
 
      Metadata.push_back(llvm::MDNode::get(Context, Args));
      continue;
    }
 
    // Link against a library.
    if (IsELF) {
      llvm::Metadata *Args[2] = {
          llvm::MDString::get(Context, "lib"),
          llvm::MDString::get(Context, LL.Library),
      };
      Metadata.push_back(llvm::MDNode::get(Context, Args));
    } else {
      llvm::SmallString<24> Opt;
      CGM.getTargetCodeGenInfo().getDependentLibraryOption(LL.Library, Opt);
      auto *OptString = llvm::MDString::get(Context, Opt);
      Metadata.push_back(llvm::MDNode::get(Context, OptString));
    }
  }
}
 
void CodeGenModule::EmitModuleInitializers(clang::Module *Primary) {
  assert(Primary->isNamedModuleUnit() &&
         "We should only emit module initializers for named modules.");
 
  // Emit the initializers in the order that sub-modules appear in the
  // source, first Global Module Fragments, if present.
  if (auto GMF = Primary->getGlobalModuleFragment()) {
    for (Decl *D : getContext().getModuleInitializers(GMF)) {
      if (isa<ImportDecl>(D))
        continue;
      assert(isa<VarDecl>(D) && "GMF initializer decl is not a var?");
      EmitTopLevelDecl(D);
    }
  }
  // Second any associated with the module, itself.
  for (Decl *D : getContext().getModuleInitializers(Primary)) {
    // Skip import decls, the inits for those are called explicitly.
    if (isa<ImportDecl>(D))
      continue;
    EmitTopLevelDecl(D);
  }
  // Third any associated with the Privat eMOdule Fragment, if present.
  if (auto PMF = Primary->getPrivateModuleFragment()) {
    for (Decl *D : getContext().getModuleInitializers(PMF)) {
      assert(isa<VarDecl>(D) && "PMF initializer decl is not a var?");
      EmitTopLevelDecl(D);
    }
  }
}
 
void CodeGenModule::EmitModuleLinkOptions() {
  // Collect the set of all of the modules we want to visit to emit link
  // options, which is essentially the imported modules and all of their
  // non-explicit child modules.
  llvm::SetVector<clang::Module *> LinkModules;
  llvm::SmallPtrSet<clang::Module *, 16> Visited;
  SmallVector<clang::Module *, 16> Stack;
 
  // Seed the stack with imported modules.
  for (Module *M : ImportedModules) {
    // Do not add any link flags when an implementation TU of a module imports
    // a header of that same module.
    if (M->getTopLevelModuleName() == getLangOpts().CurrentModule &&
        !getLangOpts().isCompilingModule())
      continue;
    if (Visited.insert(M).second)
      Stack.push_back(M);
  }
 
  // Find all of the modules to import, making a little effort to prune
  // non-leaf modules.
  while (!Stack.empty()) {
    clang::Module *Mod = Stack.pop_back_val();
 
    bool AnyChildren = false;
 
    // Visit the submodules of this module.
    for (const auto &SM : Mod->submodules()) {
      // Skip explicit children; they need to be explicitly imported to be
      // linked against.
      if (SM->IsExplicit)
        continue;
 
      if (Visited.insert(SM).second) {
        Stack.push_back(SM);
        AnyChildren = true;
      }
    }
 
    // We didn't find any children, so add this module to the list of
    // modules to link against.
    if (!AnyChildren) {
      LinkModules.insert(Mod);
    }
  }
 
  // Add link options for all of the imported modules in reverse topological
  // order.  We don't do anything to try to order import link flags with respect
  // to linker options inserted by things like #pragma comment().
  SmallVector<llvm::MDNode *, 16> MetadataArgs;
  Visited.clear();
  for (Module *M : LinkModules)
    if (Visited.insert(M).second)
      addLinkOptionsPostorder(*this, M, MetadataArgs, Visited);
  std::reverse(MetadataArgs.begin(), MetadataArgs.end());
  LinkerOptionsMetadata.append(MetadataArgs.begin(), MetadataArgs.end());
 
  // Add the linker options metadata flag.
  auto *NMD = getModule().getOrInsertNamedMetadata("llvm.linker.options");
  for (auto *MD : LinkerOptionsMetadata)
    NMD->addOperand(MD);
}
 
void CodeGenModule::EmitDeferred() {
  // Emit deferred declare target declarations.
  if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd)
    getOpenMPRuntime().emitDeferredTargetDecls();
 
  // Emit code for any potentially referenced deferred decls.  Since a
  // previously unused static decl may become used during the generation of code
  // for a static function, iterate until no changes are made.
 
  if (!DeferredVTables.empty()) {
    EmitDeferredVTables();
 
    // Emitting a vtable doesn't directly cause more vtables to
    // become deferred, although it can cause functions to be
    // emitted that then need those vtables.
    assert(DeferredVTables.empty());
  }
 
  // Emit CUDA/HIP static device variables referenced by host code only.
  // Note we should not clear CUDADeviceVarODRUsedByHost since it is still
  // needed for further handling.
  if (getLangOpts().CUDA && getLangOpts().CUDAIsDevice)
    llvm::append_range(DeferredDeclsToEmit,
                       getContext().CUDADeviceVarODRUsedByHost);
 
  // Stop if we're out of both deferred vtables and deferred declarations.
  if (DeferredDeclsToEmit.empty())
    return;
 
  // Grab the list of decls to emit. If EmitGlobalDefinition schedules more
  // work, it will not interfere with this.
  std::vector<GlobalDecl> CurDeclsToEmit;
  CurDeclsToEmit.swap(DeferredDeclsToEmit);
 
  for (GlobalDecl &D : CurDeclsToEmit) {
    // We should call GetAddrOfGlobal with IsForDefinition set to true in order
    // to get GlobalValue with exactly the type we need, not something that
    // might had been created for another decl with the same mangled name but
    // different type.
    llvm::GlobalValue *GV = dyn_cast<llvm::GlobalValue>(
        GetAddrOfGlobal(D, ForDefinition));
 
    // In case of different address spaces, we may still get a cast, even with
    // IsForDefinition equal to true. Query mangled names table to get
    // GlobalValue.
    if (!GV)
      GV = GetGlobalValue(getMangledName(D));
 
    // Make sure GetGlobalValue returned non-null.
    assert(GV);
 
    // Check to see if we've already emitted this.  This is necessary
    // for a couple of reasons: first, decls can end up in the
    // deferred-decls queue multiple times, and second, decls can end
    // up with definitions in unusual ways (e.g. by an extern inline
    // function acquiring a strong function redefinition).  Just
    // ignore these cases.
    if (!GV->isDeclaration())
      continue;
 
    // If this is OpenMP, check if it is legal to emit this global normally.
    if (LangOpts.OpenMP && OpenMPRuntime && OpenMPRuntime->emitTargetGlobal(D))
      continue;
 
    // Otherwise, emit the definition and move on to the next one.
    EmitGlobalDefinition(D, GV);
 
    // If we found out that we need to emit more decls, do that recursively.
    // This has the advantage that the decls are emitted in a DFS and related
    // ones are close together, which is convenient for testing.
    if (!DeferredVTables.empty() || !DeferredDeclsToEmit.empty()) {
      EmitDeferred();
      assert(DeferredVTables.empty() && DeferredDeclsToEmit.empty());
    }
  }
}
 
void CodeGenModule::EmitVTablesOpportunistically() {
  // Try to emit external vtables as available_externally if they have emitted
  // all inlined virtual functions.  It runs after EmitDeferred() and therefore
  // is not allowed to create new references to things that need to be emitted
  // lazily. Note that it also uses fact that we eagerly emitting RTTI.
 
  assert((OpportunisticVTables.empty() || shouldOpportunisticallyEmitVTables())
         && "Only emit opportunistic vtables with optimizations");
 
  for (const CXXRecordDecl *RD : OpportunisticVTables) {
    assert(getVTables().isVTableExternal(RD) &&
           "This queue should only contain external vtables");
    if (getCXXABI().canSpeculativelyEmitVTable(RD))
      VTables.GenerateClassData(RD);
  }
  OpportunisticVTables.clear();
}
 
void CodeGenModule::EmitGlobalAnnotations() {
  if (Annotations.empty())
    return;
 
  // Create a new global variable for the ConstantStruct in the Module.
  llvm::Constant *Array = llvm::ConstantArray::get(llvm::ArrayType::get(
    Annotations[0]->getType(), Annotations.size()), Annotations);
  auto *gv = new llvm::GlobalVariable(getModule(), Array->getType(), false,
                                      llvm::GlobalValue::AppendingLinkage,
                                      Array, "llvm.global.annotations");
  gv->setSection(AnnotationSection);
}
 
llvm::Constant *CodeGenModule::EmitAnnotationString(StringRef Str) {
  llvm::Constant *&AStr = AnnotationStrings[Str];
  if (AStr)
    return AStr;
 
  // Not found yet, create a new global.
  llvm::Constant *s = llvm::ConstantDataArray::getString(getLLVMContext(), Str);
  auto *gv = new llvm::GlobalVariable(
      getModule(), s->getType(), true, llvm::GlobalValue::PrivateLinkage, s,
      ".str", nullptr, llvm::GlobalValue::NotThreadLocal,
      ConstGlobalsPtrTy->getAddressSpace());
  gv->setSection(AnnotationSection);
  gv->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
  AStr = gv;
  return gv;
}
 
llvm::Constant *CodeGenModule::EmitAnnotationUnit(SourceLocation Loc) {
  SourceManager &SM = getContext().getSourceManager();
  PresumedLoc PLoc = SM.getPresumedLoc(Loc);
  if (PLoc.isValid())
    return EmitAnnotationString(PLoc.getFilename());
  return EmitAnnotationString(SM.getBufferName(Loc));
}
 
llvm::Constant *CodeGenModule::EmitAnnotationLineNo(SourceLocation L) {
  SourceManager &SM = getContext().getSourceManager();
  PresumedLoc PLoc = SM.getPresumedLoc(L);
  unsigned LineNo = PLoc.isValid() ? PLoc.getLine() :
    SM.getExpansionLineNumber(L);
  return llvm::ConstantInt::get(Int32Ty, LineNo);
}
 
llvm::Constant *CodeGenModule::EmitAnnotationArgs(const AnnotateAttr *Attr) {
  ArrayRef<Expr *> Exprs = {Attr->args_begin(), Attr->args_size()};
  if (Exprs.empty())
    return llvm::ConstantPointerNull::get(ConstGlobalsPtrTy);
 
  llvm::FoldingSetNodeID ID;
  for (Expr *E : Exprs) {
    ID.Add(cast<clang::ConstantExpr>(E)->getAPValueResult());
  }
  llvm::Constant *&Lookup = AnnotationArgs[ID.ComputeHash()];
  if (Lookup)
    return Lookup;
 
  llvm::SmallVector<llvm::Constant *, 4> LLVMArgs;
  LLVMArgs.reserve(Exprs.size());
  ConstantEmitter ConstEmiter(*this);
  llvm::transform(Exprs, std::back_inserter(LLVMArgs), [&](const Expr *E) {
    const auto *CE = cast<clang::ConstantExpr>(E);
    return ConstEmiter.emitAbstract(CE->getBeginLoc(), CE->getAPValueResult(),
                                    CE->getType());
  });
  auto *Struct = llvm::ConstantStruct::getAnon(LLVMArgs);
  auto *GV = new llvm::GlobalVariable(getModule(), Struct->getType(), true,
                                      llvm::GlobalValue::PrivateLinkage, Struct,
                                      ".args");
  GV->setSection(AnnotationSection);
  GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
  auto *Bitcasted = llvm::ConstantExpr::getBitCast(GV, GlobalsInt8PtrTy);
 
  Lookup = Bitcasted;
  return Bitcasted;
}
 
llvm::Constant *CodeGenModule::EmitAnnotateAttr(llvm::GlobalValue *GV,
                                                const AnnotateAttr *AA,
                                                SourceLocation L) {
  // Get the globals for file name, annotation, and the line number.
  llvm::Constant *AnnoGV = EmitAnnotationString(AA->getAnnotation()),
                 *UnitGV = EmitAnnotationUnit(L),
                 *LineNoCst = EmitAnnotationLineNo(L),
                 *Args = EmitAnnotationArgs(AA);
 
  llvm::Constant *GVInGlobalsAS = GV;
  if (GV->getAddressSpace() !=
      getDataLayout().getDefaultGlobalsAddressSpace()) {
    GVInGlobalsAS = llvm::ConstantExpr::getAddrSpaceCast(
        GV,
        llvm::PointerType::get(
            GV->getContext(), getDataLayout().getDefaultGlobalsAddressSpace()));
  }
 
  // Create the ConstantStruct for the global annotation.
  llvm::Constant *Fields[] = {
      llvm::ConstantExpr::getBitCast(GVInGlobalsAS, GlobalsInt8PtrTy),
      llvm::ConstantExpr::getBitCast(AnnoGV, ConstGlobalsPtrTy),
      llvm::ConstantExpr::getBitCast(UnitGV, ConstGlobalsPtrTy),
      LineNoCst,
      Args,
  };
  return llvm::ConstantStruct::getAnon(Fields);
}
 
void CodeGenModule::AddGlobalAnnotations(const ValueDecl *D,
                                         llvm::GlobalValue *GV) {
  assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute");
  // Get the struct elements for these annotations.
  for (const auto *I : D->specific_attrs<AnnotateAttr>())
    Annotations.push_back(EmitAnnotateAttr(GV, I, D->getLocation()));
}
 
bool CodeGenModule::isInNoSanitizeList(SanitizerMask Kind, llvm::Function *Fn,
                                       SourceLocation Loc) const {
  const auto &NoSanitizeL = getContext().getNoSanitizeList();
  // NoSanitize by function name.
  if (NoSanitizeL.containsFunction(Kind, Fn->getName()))
    return true;
  // NoSanitize by location. Check "mainfile" prefix.
  auto &SM = Context.getSourceManager();
  FileEntryRef MainFile = *SM.getFileEntryRefForID(SM.getMainFileID());
  if (NoSanitizeL.containsMainFile(Kind, MainFile.getName()))
    return true;
 
  // Check "src" prefix.
  if (Loc.isValid())
    return NoSanitizeL.containsLocation(Kind, Loc);
  // If location is unknown, this may be a compiler-generated function. Assume
  // it's located in the main file.
  return NoSanitizeL.containsFile(Kind, MainFile.getName());
}
 
bool CodeGenModule::isInNoSanitizeList(SanitizerMask Kind,
                                       llvm::GlobalVariable *GV,
                                       SourceLocation Loc, QualType Ty,
                                       StringRef Category) const {
  const auto &NoSanitizeL = getContext().getNoSanitizeList();
  if (NoSanitizeL.containsGlobal(Kind, GV->getName(), Category))
    return true;
  auto &SM = Context.getSourceManager();
  if (NoSanitizeL.containsMainFile(
          Kind, SM.getFileEntryRefForID(SM.getMainFileID())->getName(),
          Category))
    return true;
  if (NoSanitizeL.containsLocation(Kind, Loc, Category))
    return true;
 
  // Check global type.
  if (!Ty.isNull()) {
    // Drill down the array types: if global variable of a fixed type is
    // not sanitized, we also don't instrument arrays of them.
    while (auto AT = dyn_cast<ArrayType>(Ty.getTypePtr()))
      Ty = AT->getElementType();
    Ty = Ty.getCanonicalType().getUnqualifiedType();
    // Only record types (classes, structs etc.) are ignored.
    if (Ty->isRecordType()) {
      std::string TypeStr = Ty.getAsString(getContext().getPrintingPolicy());
      if (NoSanitizeL.containsType(Kind, TypeStr, Category))
        return true;
    }
  }
  return false;
}
 
bool CodeGenModule::imbueXRayAttrs(llvm::Function *Fn, SourceLocation Loc,
                                   StringRef Category) const {
  const auto &XRayFilter = getContext().getXRayFilter();
  using ImbueAttr = XRayFunctionFilter::ImbueAttribute;
  auto Attr = ImbueAttr::NONE;
  if (Loc.isValid())
    Attr = XRayFilter.shouldImbueLocation(Loc, Category);
  if (Attr == ImbueAttr::NONE)
    Attr = XRayFilter.shouldImbueFunction(Fn->getName());
  switch (Attr) {
  case ImbueAttr::NONE:
    return false;
  case ImbueAttr::ALWAYS:
    Fn->addFnAttr("function-instrument", "xray-always");
    break;
  case ImbueAttr::ALWAYS_ARG1:
    Fn->addFnAttr("function-instrument", "xray-always");
    Fn->addFnAttr("xray-log-args", "1");
    break;
  case ImbueAttr::NEVER:
    Fn->addFnAttr("function-instrument", "xray-never");
    break;
  }
  return true;
}
 
ProfileList::ExclusionType
CodeGenModule::isFunctionBlockedByProfileList(llvm::Function *Fn,
                                              SourceLocation Loc) const {
  const auto &ProfileList = getContext().getProfileList();
  // If the profile list is empty, then instrument everything.
  if (ProfileList.isEmpty())
    return ProfileList::Allow;
  CodeGenOptions::ProfileInstrKind Kind = getCodeGenOpts().getProfileInstr();
  // First, check the function name.
  if (auto V = ProfileList.isFunctionExcluded(Fn->getName(), Kind))
    return *V;
  // Next, check the source location.
  if (Loc.isValid())
    if (auto V = ProfileList.isLocationExcluded(Loc, Kind))
      return *V;
  // If location is unknown, this may be a compiler-generated function. Assume
  // it's located in the main file.
  auto &SM = Context.getSourceManager();
  if (auto MainFile = SM.getFileEntryRefForID(SM.getMainFileID()))
    if (auto V = ProfileList.isFileExcluded(MainFile->getName(), Kind))
      return *V;
  return ProfileList.getDefault(Kind);
}
 
ProfileList::ExclusionType
CodeGenModule::isFunctionBlockedFromProfileInstr(llvm::Function *Fn,
                                                 SourceLocation Loc) const {
  auto V = isFunctionBlockedByProfileList(Fn, Loc);
  if (V != ProfileList::Allow)
    return V;
 
  auto NumGroups = getCodeGenOpts().ProfileTotalFunctionGroups;
  if (NumGroups > 1) {
    auto Group = llvm::crc32(arrayRefFromStringRef(Fn->getName())) % NumGroups;
    if (Group != getCodeGenOpts().ProfileSelectedFunctionGroup)
      return ProfileList::Skip;
  }
  return ProfileList::Allow;
}
 
bool CodeGenModule::MustBeEmitted(const ValueDecl *Global) {
  // Never defer when EmitAllDecls is specified.
  if (LangOpts.EmitAllDecls)
    return true;
 
  const auto *VD = dyn_cast<VarDecl>(Global);
  if (VD &&
      ((CodeGenOpts.KeepPersistentStorageVariables &&
        (VD->getStorageDuration() == SD_Static ||
         VD->getStorageDuration() == SD_Thread)) ||
       (CodeGenOpts.KeepStaticConsts && VD->getStorageDuration() == SD_Static &&
        VD->getType().isConstQualified())))
    return true;
 
  return getContext().DeclMustBeEmitted(Global);
}
 
bool CodeGenModule::MayBeEmittedEagerly(const ValueDecl *Global) {
  // In OpenMP 5.0 variables and function may be marked as
  // device_type(host/nohost) and we should not emit them eagerly unless we sure
  // that they must be emitted on the host/device. To be sure we need to have
  // seen a declare target with an explicit mentioning of the function, we know
  // we have if the level of the declare target attribute is -1. Note that we
  // check somewhere else if we should emit this at all.
  if (LangOpts.OpenMP >= 50 && !LangOpts.OpenMPSimd) {
    std::optional<OMPDeclareTargetDeclAttr *> ActiveAttr =
        OMPDeclareTargetDeclAttr::getActiveAttr(Global);
    if (!ActiveAttr || (*ActiveAttr)->getLevel() != (unsigned)-1)
      return false;
  }
 
  if (const auto *FD = dyn_cast<FunctionDecl>(Global)) {
    if (FD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
      // Implicit template instantiations may change linkage if they are later
      // explicitly instantiated, so they should not be emitted eagerly.
      return false;
  }
  if (const auto *VD = dyn_cast<VarDecl>(Global)) {
    if (Context.getInlineVariableDefinitionKind(VD) ==
        ASTContext::InlineVariableDefinitionKind::WeakUnknown)
      // A definition of an inline constexpr static data member may change
      // linkage later if it's redeclared outside the class.
      return false;
    if (CXX20ModuleInits && VD->getOwningModule() &&
        !VD->getOwningModule()->isModuleMapModule()) {
      // For CXX20, module-owned initializers need to be deferred, since it is
      // not known at this point if they will be run for the current module or
      // as part of the initializer for an imported one.
      return false;
    }
  }
  // If OpenMP is enabled and threadprivates must be generated like TLS, delay
  // codegen for global variables, because they may be marked as threadprivate.
  if (LangOpts.OpenMP && LangOpts.OpenMPUseTLS &&
      getContext().getTargetInfo().isTLSSupported() && isa<VarDecl>(Global) &&
      !Global->getType().isConstantStorage(getContext(), false, false) &&
      !OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(Global))
    return false;
 
  return true;
}
 
ConstantAddress CodeGenModule::GetAddrOfMSGuidDecl(const MSGuidDecl *GD) {
  StringRef Name = getMangledName(GD);
 
  // The UUID descriptor should be pointer aligned.
  CharUnits Alignment = CharUnits::fromQuantity(PointerAlignInBytes);
 
  // Look for an existing global.
  if (llvm::GlobalVariable *GV = getModule().getNamedGlobal(Name))
    return ConstantAddress(GV, GV->getValueType(), Alignment);
 
  ConstantEmitter Emitter(*this);
  llvm::Constant *Init;
 
  APValue &V = GD->getAsAPValue();
  if (!V.isAbsent()) {
    // If possible, emit the APValue version of the initializer. In particular,
    // this gets the type of the constant right.
    Init = Emitter.emitForInitializer(
        GD->getAsAPValue(), GD->getType().getAddressSpace(), GD->getType());
  } else {
    // As a fallback, directly construct the constant.
    // FIXME: This may get padding wrong under esoteric struct layout rules.
    // MSVC appears to create a complete type 'struct __s_GUID' that it
    // presumably uses to represent these constants.
    MSGuidDecl::Parts Parts = GD->getParts();
    llvm::Constant *Fields[4] = {
        llvm::ConstantInt::get(Int32Ty, Parts.Part1),
        llvm::ConstantInt::get(Int16Ty, Parts.Part2),
        llvm::ConstantInt::get(Int16Ty, Parts.Part3),
        llvm::ConstantDataArray::getRaw(
            StringRef(reinterpret_cast<char *>(Parts.Part4And5), 8), 8,
            Int8Ty)};
    Init = llvm::ConstantStruct::getAnon(Fields);
  }
 
  auto *GV = new llvm::GlobalVariable(
      getModule(), Init->getType(),
      /*isConstant=*/true, llvm::GlobalValue::LinkOnceODRLinkage, Init, Name);
  if (supportsCOMDAT())
    GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
  setDSOLocal(GV);
 
  if (!V.isAbsent()) {
    Emitter.finalize(GV);
    return ConstantAddress(GV, GV->getValueType(), Alignment);
  }
 
  llvm::Type *Ty = getTypes().ConvertTypeForMem(GD->getType());
  return ConstantAddress(GV, Ty, Alignment);
}
 
ConstantAddress CodeGenModule::GetAddrOfUnnamedGlobalConstantDecl(
    const UnnamedGlobalConstantDecl *GCD) {
  CharUnits Alignment = getContext().getTypeAlignInChars(GCD->getType());
 
  llvm::GlobalVariable **Entry = nullptr;
  Entry = &UnnamedGlobalConstantDeclMap[GCD];
  if (*Entry)
    return ConstantAddress(*Entry, (*Entry)->getValueType(), Alignment);
 
  ConstantEmitter Emitter(*this);
  llvm::Constant *Init;
 
  const APValue &V = GCD->getValue();
 
  assert(!V.isAbsent());
  Init = Emitter.emitForInitializer(V, GCD->getType().getAddressSpace(),
                                    GCD->getType());
 
  auto *GV = new llvm::GlobalVariable(getModule(), Init->getType(),
                                      /*isConstant=*/true,
                                      llvm::GlobalValue::PrivateLinkage, Init,
                                      ".constant");
  GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
  GV->setAlignment(Alignment.getAsAlign());
 
  Emitter.finalize(GV);
 
  *Entry = GV;
  return ConstantAddress(GV, GV->getValueType(), Alignment);
}
 
ConstantAddress CodeGenModule::GetAddrOfTemplateParamObject(
    const TemplateParamObjectDecl *TPO) {
  StringRef Name = getMangledName(TPO);
  CharUnits Alignment = getNaturalTypeAlignment(TPO->getType());
 
  if (llvm::GlobalVariable *GV = getModule().getNamedGlobal(Name))
    return ConstantAddress(GV, GV->getValueType(), Alignment);
 
  ConstantEmitter Emitter(*this);
  llvm::Constant *Init = Emitter.emitForInitializer(
        TPO->getValue(), TPO->getType().getAddressSpace(), TPO->getType());
 
  if (!Init) {
    ErrorUnsupported(TPO, "template parameter object");
    return ConstantAddress::invalid();
  }
 
  llvm::GlobalValue::LinkageTypes Linkage =
      isExternallyVisible(TPO->getLinkageAndVisibility().getLinkage())
          ? llvm::GlobalValue::LinkOnceODRLinkage
          : llvm::GlobalValue::InternalLinkage;
  auto *GV = new llvm::GlobalVariable(getModule(), Init->getType(),
                                      /*isConstant=*/true, Linkage, Init, Name);
  setGVProperties(GV, TPO);
  if (supportsCOMDAT())
    GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
  Emitter.finalize(GV);
 
  return ConstantAddress(GV, GV->getValueType(), Alignment);
}
 
ConstantAddress CodeGenModule::GetWeakRefReference(const ValueDecl *VD) {
  const AliasAttr *AA = VD->getAttr<AliasAttr>();
  assert(AA && "No alias?");
 
  CharUnits Alignment = getContext().getDeclAlign(VD);
  llvm::Type *DeclTy = getTypes().ConvertTypeForMem(VD->getType());
 
  // See if there is already something with the target's name in the module.
  llvm::GlobalValue *Entry = GetGlobalValue(AA->getAliasee());
  if (Entry)
    return ConstantAddress(Entry, DeclTy, Alignment);
 
  llvm::Constant *Aliasee;
  if (isa<llvm::FunctionType>(DeclTy))
    Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy,
                                      GlobalDecl(cast<FunctionDecl>(VD)),
                                      /*ForVTable=*/false);
  else
    Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), DeclTy, LangAS::Default,
                                    nullptr);
 
  auto *F = cast<llvm::GlobalValue>(Aliasee);
  F->setLinkage(llvm::Function::ExternalWeakLinkage);
  WeakRefReferences.insert(F);
 
  return ConstantAddress(Aliasee, DeclTy, Alignment);
}
 
void CodeGenModule::EmitGlobal(GlobalDecl GD) {
  const auto *Global = cast<ValueDecl>(GD.getDecl());
 
  // Weak references don't produce any output by themselves.
  if (Global->hasAttr<WeakRefAttr>())
    return;
 
  // If this is an alias definition (which otherwise looks like a declaration)
  // emit it now.
  if (Global->hasAttr<AliasAttr>())
    return EmitAliasDefinition(GD);
 
  // IFunc like an alias whose value is resolved at runtime by calling resolver.
  if (Global->hasAttr<IFuncAttr>())
    return emitIFuncDefinition(GD);
 
  // If this is a cpu_dispatch multiversion function, emit the resolver.
  if (Global->hasAttr<CPUDispatchAttr>())
    return emitCPUDispatchDefinition(GD);
 
  // If this is CUDA, be selective about which declarations we emit.
  if (LangOpts.CUDA) {
    if (LangOpts.CUDAIsDevice) {
      if (!Global->hasAttr<CUDADeviceAttr>() &&
          !Global->hasAttr<CUDAGlobalAttr>() &&
          !Global->hasAttr<CUDAConstantAttr>() &&
          !Global->hasAttr<CUDASharedAttr>() &&
          !Global->getType()->isCUDADeviceBuiltinSurfaceType() &&
          !Global->getType()->isCUDADeviceBuiltinTextureType())
        return;
    } else {
      // We need to emit host-side 'shadows' for all global
      // device-side variables because the CUDA runtime needs their
      // size and host-side address in order to provide access to
      // their device-side incarnations.
 
      // So device-only functions are the only things we skip.
      if (isa<FunctionDecl>(Global) && !Global->hasAttr<CUDAHostAttr>() &&
          Global->hasAttr<CUDADeviceAttr>())
        return;
 
      assert((isa<FunctionDecl>(Global) || isa<VarDecl>(Global)) &&
             "Expected Variable or Function");
    }
  }
 
  if (LangOpts.OpenMP) {
    // If this is OpenMP, check if it is legal to emit this global normally.
    if (OpenMPRuntime && OpenMPRuntime->emitTargetGlobal(GD))
      return;
    if (auto *DRD = dyn_cast<OMPDeclareReductionDecl>(Global)) {
      if (MustBeEmitted(Global))
        EmitOMPDeclareReduction(DRD);
      return;
    }
    if (auto *DMD = dyn_cast<OMPDeclareMapperDecl>(Global)) {
      if (MustBeEmitted(Global))
        EmitOMPDeclareMapper(DMD);
      return;
    }
  }
 
  // Ignore declarations, they will be emitted on their first use.
  if (const auto *FD = dyn_cast<FunctionDecl>(Global)) {
    // Forward declarations are emitted lazily on first use.
    if (!FD->doesThisDeclarationHaveABody()) {
      if (!FD->doesDeclarationForceExternallyVisibleDefinition())
        return;
 
      StringRef MangledName = getMangledName(GD);
 
      // Compute the function info and LLVM type.
      const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
      llvm::Type *Ty = getTypes().GetFunctionType(FI);
 
      GetOrCreateLLVMFunction(MangledName, Ty, GD, /*ForVTable=*/false,
                              /*DontDefer=*/false);
      return;
    }
  } else {
    const auto *VD = cast<VarDecl>(Global);
    assert(VD->isFileVarDecl() && "Cannot emit local var decl as global.");
    if (VD->isThisDeclarationADefinition() != VarDecl::Definition &&
        !Context.isMSStaticDataMemberInlineDefinition(VD)) {
      if (LangOpts.OpenMP) {
        // Emit declaration of the must-be-emitted declare target variable.
        if (std::optional<OMPDeclareTargetDeclAttr::MapTypeTy> Res =
                OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD)) {
 
          // If this variable has external storage and doesn't require special
          // link handling we defer to its canonical definition.
          if (VD->hasExternalStorage() &&
              Res != OMPDeclareTargetDeclAttr::MT_Link)
            return;
 
          bool UnifiedMemoryEnabled =
              getOpenMPRuntime().hasRequiresUnifiedSharedMemory();
          if ((*Res == OMPDeclareTargetDeclAttr::MT_To ||
               *Res == OMPDeclareTargetDeclAttr::MT_Enter) &&
              !UnifiedMemoryEnabled) {
            (void)GetAddrOfGlobalVar(VD);
          } else {
            assert(((*Res == OMPDeclareTargetDeclAttr::MT_Link) ||
                    ((*Res == OMPDeclareTargetDeclAttr::MT_To ||
                      *Res == OMPDeclareTargetDeclAttr::MT_Enter) &&
                     UnifiedMemoryEnabled)) &&
                   "Link clause or to clause with unified memory expected.");
            (void)getOpenMPRuntime().getAddrOfDeclareTargetVar(VD);
          }
 
          return;
        }
      }
      // If this declaration may have caused an inline variable definition to
      // change linkage, make sure that it's emitted.
      if (Context.getInlineVariableDefinitionKind(VD) ==
          ASTContext::InlineVariableDefinitionKind::Strong)
        GetAddrOfGlobalVar(VD);
      return;
    }
  }
 
  // Defer code generation to first use when possible, e.g. if this is an inline
  // function. If the global must always be emitted, do it eagerly if possible
  // to benefit from cache locality.
  if (MustBeEmitted(Global) && MayBeEmittedEagerly(Global)) {
    // Emit the definition if it can't be deferred.
    EmitGlobalDefinition(GD);
    addEmittedDeferredDecl(GD);
    return;
  }
 
  // If we're deferring emission of a C++ variable with an
  // initializer, remember the order in which it appeared in the file.
  if (getLangOpts().CPlusPlus && isa<VarDecl>(Global) &&
      cast<VarDecl>(Global)->hasInit()) {
    DelayedCXXInitPosition[Global] = CXXGlobalInits.size();
    CXXGlobalInits.push_back(nullptr);
  }
 
  StringRef MangledName = getMangledName(GD);
  if (GetGlobalValue(MangledName) != nullptr) {
    // The value has already been used and should therefore be emitted.
    addDeferredDeclToEmit(GD);
  } else if (MustBeEmitted(Global)) {
    // The value must be emitted, but cannot be emitted eagerly.
    assert(!MayBeEmittedEagerly(Global));
    addDeferredDeclToEmit(GD);
  } else {
    // Otherwise, remember that we saw a deferred decl with this name.  The
    // first use of the mangled name will cause it to move into
    // DeferredDeclsToEmit.
    DeferredDecls[MangledName] = GD;
  }
}
 
// Check if T is a class type with a destructor that's not dllimport.
static bool HasNonDllImportDtor(QualType T) {
  if (const auto *RT = T->getBaseElementTypeUnsafe()->getAs<RecordType>())
    if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()))
      if (RD->getDestructor() && !RD->getDestructor()->hasAttr<DLLImportAttr>())
        return true;
 
  return false;
}
 
namespace {
  struct FunctionIsDirectlyRecursive
      : public ConstStmtVisitor<FunctionIsDirectlyRecursive, bool> {
    const StringRef Name;
    const Builtin::Context &BI;
    FunctionIsDirectlyRecursive(StringRef N, const Builtin::Context &C)
        : Name(N), BI(C) {}
 
    bool VisitCallExpr(const CallExpr *E) {
      const FunctionDecl *FD = E->getDirectCallee();
      if (!FD)
        return false;
      AsmLabelAttr *Attr = FD->getAttr<AsmLabelAttr>();
      if (Attr && Name == Attr->getLabel())
        return true;
      unsigned BuiltinID = FD->getBuiltinID();
      if (!BuiltinID || !BI.isLibFunction(BuiltinID))
        return false;
      StringRef BuiltinName = BI.getName(BuiltinID);
      if (BuiltinName.startswith("__builtin_") &&
          Name == BuiltinName.slice(strlen("__builtin_"), StringRef::npos)) {
        return true;
      }
      return false;
    }
 
    bool VisitStmt(const Stmt *S) {
      for (const Stmt *Child : S->children())
        if (Child && this->Visit(Child))
          return true;
      return false;
    }
  };
 
  // Make sure we're not referencing non-imported vars or functions.
  struct DLLImportFunctionVisitor
      : public RecursiveASTVisitor<DLLImportFunctionVisitor> {
    bool SafeToInline = true;
 
    bool shouldVisitImplicitCode() const { return true; }
 
    bool VisitVarDecl(VarDecl *VD) {
      if (VD->getTLSKind()) {
        // A thread-local variable cannot be imported.
        SafeToInline = false;
        return SafeToInline;
      }
 
      // A variable definition might imply a destructor call.
      if (VD->isThisDeclarationADefinition())
        SafeToInline = !HasNonDllImportDtor(VD->getType());
 
      return SafeToInline;
    }
 
    bool VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
      if (const auto *D = E->getTemporary()->getDestructor())
        SafeToInline = D->hasAttr<DLLImportAttr>();
      return SafeToInline;
    }
 
    bool VisitDeclRefExpr(DeclRefExpr *E) {
      ValueDecl *VD = E->getDecl();
      if (isa<FunctionDecl>(VD))
        SafeToInline = VD->hasAttr<DLLImportAttr>();
      else if (VarDecl *V = dyn_cast<VarDecl>(VD))
        SafeToInline = !V->hasGlobalStorage() || V->hasAttr<DLLImportAttr>();
      return SafeToInline;
    }
 
    bool VisitCXXConstructExpr(CXXConstructExpr *E) {
      SafeToInline = E->getConstructor()->hasAttr<DLLImportAttr>();
      return SafeToInline;
    }
 
    bool VisitCXXMemberCallExpr(CXXMemberCallExpr *E) {
      CXXMethodDecl *M = E->getMethodDecl();
      if (!M) {
        // Call through a pointer to member function. This is safe to inline.
        SafeToInline = true;
      } else {
        SafeToInline = M->hasAttr<DLLImportAttr>();
      }
      return SafeToInline;
    }
 
    bool VisitCXXDeleteExpr(CXXDeleteExpr *E) {
      SafeToInline = E->getOperatorDelete()->hasAttr<DLLImportAttr>();
      return SafeToInline;
    }
 
    bool VisitCXXNewExpr(CXXNewExpr *E) {
      SafeToInline = E->getOperatorNew()->hasAttr<DLLImportAttr>();
      return SafeToInline;
    }
  };
}
 
// isTriviallyRecursive - Check if this function calls another
// decl that, because of the asm attribute or the other decl being a builtin,
// ends up pointing to itself.
bool
CodeGenModule::isTriviallyRecursive(const FunctionDecl *FD) {
  StringRef Name;
  if (getCXXABI().getMangleContext().shouldMangleDeclName(FD)) {
    // asm labels are a special kind of mangling we have to support.
    AsmLabelAttr *Attr = FD->getAttr<AsmLabelAttr>();
    if (!Attr)
      return false;
    Name = Attr->getLabel();
  } else {
    Name = FD->getName();
  }
 
  FunctionIsDirectlyRecursive Walker(Name, Context.BuiltinInfo);
  const Stmt *Body = FD->getBody();
  return Body ? Walker.Visit(Body) : false;
}
 
bool CodeGenModule::shouldEmitFunction(GlobalDecl GD) {
  if (getFunctionLinkage(GD) != llvm::Function::AvailableExternallyLinkage)
    return true;
  const auto *F = cast<FunctionDecl>(GD.getDecl());
  if (CodeGenOpts.OptimizationLevel == 0 && !F->hasAttr<AlwaysInlineAttr>())
    return false;
 
  if (F->hasAttr<DLLImportAttr>() && !F->hasAttr<AlwaysInlineAttr>()) {
    // Check whether it would be safe to inline this dllimport function.
    DLLImportFunctionVisitor Visitor;
    Visitor.TraverseFunctionDecl(const_cast<FunctionDecl*>(F));
    if (!Visitor.SafeToInline)
      return false;
 
    if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(F)) {
      // Implicit destructor invocations aren't captured in the AST, so the
      // check above can't see them. Check for them manually here.
      for (const Decl *Member : Dtor->getParent()->decls())
        if (isa<FieldDecl>(Member))
          if (HasNonDllImportDtor(cast<FieldDecl>(Member)->getType()))
            return false;
      for (const CXXBaseSpecifier &B : Dtor->getParent()->bases())
        if (HasNonDllImportDtor(B.getType()))
          return false;
    }
  }
 
  // Inline builtins declaration must be emitted. They often are fortified
  // functions.
  if (F->isInlineBuiltinDeclaration())
    return true;
 
  // PR9614. Avoid cases where the source code is lying to us. An available
  // externally function should have an equivalent function somewhere else,
  // but a function that calls itself through asm label/`__builtin_` trickery is
  // clearly not equivalent to the real implementation.
  // This happens in glibc's btowc and in some configure checks.
  return !isTriviallyRecursive(F);
}
 
bool CodeGenModule::shouldOpportunisticallyEmitVTables() {
  return CodeGenOpts.OptimizationLevel > 0;
}
 
void CodeGenModule::EmitMultiVersionFunctionDefinition(GlobalDecl GD,
                                                       llvm::GlobalValue *GV) {
  const auto *FD = cast<FunctionDecl>(GD.getDecl());
 
  if (FD->isCPUSpecificMultiVersion()) {
    auto *Spec = FD->getAttr<CPUSpecificAttr>();
    for (unsigned I = 0; I < Spec->cpus_size(); ++I)
      EmitGlobalFunctionDefinition(GD.getWithMultiVersionIndex(I), nullptr);
  } else if (FD->isTargetClonesMultiVersion()) {
    auto *Clone = FD->getAttr<TargetClonesAttr>();
    for (unsigned I = 0; I < Clone->featuresStrs_size(); ++I)
      if (Clone->isFirstOfVersion(I))
        EmitGlobalFunctionDefinition(GD.getWithMultiVersionIndex(I), nullptr);
    // Ensure that the resolver function is also emitted.
    GetOrCreateMultiVersionResolver(GD);
  } else
    EmitGlobalFunctionDefinition(GD, GV);
}
 
void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD, llvm::GlobalValue *GV) {
  const auto *D = cast<ValueDecl>(GD.getDecl());
 
  PrettyStackTraceDecl CrashInfo(const_cast<ValueDecl *>(D), D->getLocation(),
                                 Context.getSourceManager(),
                                 "Generating code for declaration");
 
  if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
    // At -O0, don't generate IR for functions with available_externally
    // linkage.
    if (!shouldEmitFunction(GD))
      return;
 
    llvm::TimeTraceScope TimeScope("CodeGen Function", [&]() {
      std::string Name;
      llvm::raw_string_ostream OS(Name);
      FD->getNameForDiagnostic(OS, getContext().getPrintingPolicy(),
                               /*Qualified=*/true);
      return Name;
    });
 
    if (const auto *Method = dyn_cast<CXXMethodDecl>(D)) {
      // Make sure to emit the definition(s) before we emit the thunks.
      // This is necessary for the generation of certain thunks.
      if (isa<CXXConstructorDecl>(Method) || isa<CXXDestructorDecl>(Method))
        ABI->emitCXXStructor(GD);
      else if (FD->isMultiVersion())
        EmitMultiVersionFunctionDefinition(GD, GV);
      else
        EmitGlobalFunctionDefinition(GD, GV);
 
      if (Method->isVirtual())
        getVTables().EmitThunks(GD);
 
      return;
    }
 
    if (FD->isMultiVersion())
      return EmitMultiVersionFunctionDefinition(GD, GV);
    return EmitGlobalFunctionDefinition(GD, GV);
  }
 
  if (const auto *VD = dyn_cast<VarDecl>(D))
    return EmitGlobalVarDefinition(VD, !VD->hasDefinition());
 
  llvm_unreachable("Invalid argument to EmitGlobalDefinition()");
}
 
static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old,
                                                      llvm::Function *NewFn);
 
static unsigned
TargetMVPriority(const TargetInfo &TI,
                 const CodeGenFunction::MultiVersionResolverOption &RO) {
  unsigned Priority = 0;
  unsigned NumFeatures = 0;
  for (StringRef Feat : RO.Conditions.Features) {
    Priority = std::max(Priority, TI.multiVersionSortPriority(Feat));
    NumFeatures++;
  }
 
  if (!RO.Conditions.Architecture.empty())
    Priority = std::max(
        Priority, TI.multiVersionSortPriority(RO.Conditions.Architecture));
 
  Priority += TI.multiVersionFeatureCost() * NumFeatures;
 
  return Priority;
}
 
// Multiversion functions should be at most 'WeakODRLinkage' so that a different
// TU can forward declare the function without causing problems.  Particularly
// in the cases of CPUDispatch, this causes issues. This also makes sure we
// work with internal linkage functions, so that the same function name can be
// used with internal linkage in multiple TUs.
llvm::GlobalValue::LinkageTypes getMultiversionLinkage(CodeGenModule &CGM,
                                                       GlobalDecl GD) {
  const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
  if (FD->getFormalLinkage() == InternalLinkage)
    return llvm::GlobalValue::InternalLinkage;
  return llvm::GlobalValue::WeakODRLinkage;
}
 
void CodeGenModule::emitMultiVersionFunctions() {
  std::vector<GlobalDecl> MVFuncsToEmit;
  MultiVersionFuncs.swap(MVFuncsToEmit);
  for (GlobalDecl GD : MVFuncsToEmit) {
    const auto *FD = cast<FunctionDecl>(GD.getDecl());
    assert(FD && "Expected a FunctionDecl");
 
    SmallVector<CodeGenFunction::MultiVersionResolverOption, 10> Options;
    if (FD->isTargetMultiVersion()) {
      getContext().forEachMultiversionedFunctionVersion(
          FD, [this, &GD, &Options](const FunctionDecl *CurFD) {
            GlobalDecl CurGD{
                (CurFD->isDefined() ? CurFD->getDefinition() : CurFD)};
            StringRef MangledName = getMangledName(CurGD);
            llvm::Constant *Func = GetGlobalValue(MangledName);
            if (!Func) {
              if (CurFD->isDefined()) {
                EmitGlobalFunctionDefinition(CurGD, nullptr);
                Func = GetGlobalValue(MangledName);
              } else {
                const CGFunctionInfo &FI =
                    getTypes().arrangeGlobalDeclaration(GD);
                llvm::FunctionType *Ty = getTypes().GetFunctionType(FI);
                Func = GetAddrOfFunction(CurGD, Ty, /*ForVTable=*/false,
                                         /*DontDefer=*/false, ForDefinition);
              }
              assert(Func && "This should have just been created");
            }
            if (CurFD->getMultiVersionKind() == MultiVersionKind::Target) {
              const auto *TA = CurFD->getAttr<TargetAttr>();
              llvm::SmallVector<StringRef, 8> Feats;
              TA->getAddedFeatures(Feats);
              Options.emplace_back(cast<llvm::Function>(Func),
                                   TA->getArchitecture(), Feats);
            } else {
              const auto *TVA = CurFD->getAttr<TargetVersionAttr>();
              llvm::SmallVector<StringRef, 8> Feats;
              TVA->getFeatures(Feats);
              Options.emplace_back(cast<llvm::Function>(Func),
                                   /*Architecture*/ "", Feats);
            }
          });
    } else if (FD->isTargetClonesMultiVersion()) {
      const auto *TC = FD->getAttr<TargetClonesAttr>();
      for (unsigned VersionIndex = 0; VersionIndex < TC->featuresStrs_size();
           ++VersionIndex) {
        if (!TC->isFirstOfVersion(VersionIndex))
          continue;
        GlobalDecl CurGD{(FD->isDefined() ? FD->getDefinition() : FD),
                         VersionIndex};
        StringRef Version = TC->getFeatureStr(VersionIndex);
        StringRef MangledName = getMangledName(CurGD);
        llvm::Constant *Func = GetGlobalValue(MangledName);
        if (!Func) {
          if (FD->isDefined()) {
            EmitGlobalFunctionDefinition(CurGD, nullptr);
            Func = GetGlobalValue(MangledName);
          } else {
            const CGFunctionInfo &FI =
                getTypes().arrangeGlobalDeclaration(CurGD);
            llvm::FunctionType *Ty = getTypes().GetFunctionType(FI);
            Func = GetAddrOfFunction(CurGD, Ty, /*ForVTable=*/false,
                                     /*DontDefer=*/false, ForDefinition);
          }
          assert(Func && "This should have just been created");
        }
 
        StringRef Architecture;
        llvm::SmallVector<StringRef, 1> Feature;
 
        if (getTarget().getTriple().isAArch64()) {
          if (Version != "default") {
            llvm::SmallVector<StringRef, 8> VerFeats;
            Version.split(VerFeats, "+");
            for (auto &CurFeat : VerFeats)
              Feature.push_back(CurFeat.trim());
          }
        } else {
          if (Version.startswith("arch="))
            Architecture = Version.drop_front(sizeof("arch=") - 1);
          else if (Version != "default")
            Feature.push_back(Version);
        }
 
        Options.emplace_back(cast<llvm::Function>(Func), Architecture, Feature);
      }
    } else {
      assert(0 && "Expected a target or target_clones multiversion function");
      continue;
    }
 
    llvm::Constant *ResolverConstant = GetOrCreateMultiVersionResolver(GD);
    if (auto *IFunc = dyn_cast<llvm::GlobalIFunc>(ResolverConstant))
      ResolverConstant = IFunc->getResolver();
    llvm::Function *ResolverFunc = cast<llvm::Function>(ResolverConstant);
 
    ResolverFunc->setLinkage(getMultiversionLinkage(*this, GD));
 
    if (!ResolverFunc->hasLocalLinkage() && supportsCOMDAT())
      ResolverFunc->setComdat(
          getModule().getOrInsertComdat(ResolverFunc->getName()));
 
    const TargetInfo &TI = getTarget();
    llvm::stable_sort(
        Options, [&TI](const CodeGenFunction::MultiVersionResolverOption &LHS,
                       const CodeGenFunction::MultiVersionResolverOption &RHS) {
          return TargetMVPriority(TI, LHS) > TargetMVPriority(TI, RHS);
        });
    CodeGenFunction CGF(*this);
    CGF.EmitMultiVersionResolver(ResolverFunc, Options);
  }
 
  // Ensure that any additions to the deferred decls list caused by emitting a
  // variant are emitted.  This can happen when the variant itself is inline and
  // calls a function without linkage.
  if (!MVFuncsToEmit.empty())
    EmitDeferred();
 
  // Ensure that any additions to the multiversion funcs list from either the
  // deferred decls or the multiversion functions themselves are emitted.
  if (!MultiVersionFuncs.empty())
    emitMultiVersionFunctions();
}
 
void CodeGenModule::emitCPUDispatchDefinition(GlobalDecl GD) {
  const auto *FD = cast<FunctionDecl>(GD.getDecl());
  assert(FD && "Not a FunctionDecl?");
  assert(FD->isCPUDispatchMultiVersion() && "Not a multiversion function?");
  const auto *DD = FD->getAttr<CPUDispatchAttr>();
  assert(DD && "Not a cpu_dispatch Function?");
 
  const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
  llvm::FunctionType *DeclTy = getTypes().GetFunctionType(FI);
 
  StringRef ResolverName = getMangledName(GD);
  UpdateMultiVersionNames(GD, FD, ResolverName);
 
  llvm::Type *ResolverType;
  GlobalDecl ResolverGD;
  if (getTarget().supportsIFunc()) {
    ResolverType = llvm::FunctionType::get(
        llvm::PointerType::get(DeclTy,
                               getTypes().getTargetAddressSpace(FD->getType())),
        false);
  }
  else {
    ResolverType = DeclTy;
    ResolverGD = GD;
  }
 
  auto *ResolverFunc = cast<llvm::Function>(GetOrCreateLLVMFunction(
      ResolverName, ResolverType, ResolverGD, /*ForVTable=*/false));
  ResolverFunc->setLinkage(getMultiversionLinkage(*this, GD));
  if (supportsCOMDAT())
    ResolverFunc->setComdat(
        getModule().getOrInsertComdat(ResolverFunc->getName()));
 
  SmallVector<CodeGenFunction::MultiVersionResolverOption, 10> Options;
  const TargetInfo &Target = getTarget();
  unsigned Index = 0;
  for (const IdentifierInfo *II : DD->cpus()) {
    // Get the name of the target function so we can look it up/create it.
    std::string MangledName = getMangledNameImpl(*this, GD, FD, true) +
                              getCPUSpecificMangling(*this, II->getName());
 
    llvm::Constant *Func = GetGlobalValue(MangledName);
 
    if (!Func) {
      GlobalDecl ExistingDecl = Manglings.lookup(MangledName);
      if (ExistingDecl.getDecl() &&
          ExistingDecl.getDecl()->getAsFunction()->isDefined()) {
        EmitGlobalFunctionDefinition(ExistingDecl, nullptr);
        Func = GetGlobalValue(MangledName);
      } else {
        if (!ExistingDecl.getDecl())
          ExistingDecl = GD.getWithMultiVersionIndex(Index);
 
      Func = GetOrCreateLLVMFunction(
          MangledName, DeclTy, ExistingDecl,
          /*ForVTable=*/false, /*DontDefer=*/true,
          /*IsThunk=*/false, llvm::AttributeList(), ForDefinition);
      }
    }
 
    llvm::SmallVector<StringRef, 32> Features;
    Target.getCPUSpecificCPUDispatchFeatures(II->getName(), Features);
    llvm::transform(Features, Features.begin(),
                    [](StringRef Str) { return Str.substr(1); });
    llvm::erase_if(Features, [&Target](StringRef Feat) {
      return !Target.validateCpuSupports(Feat);
    });
    Options.emplace_back(cast<llvm::Function>(Func), StringRef{}, Features);
    ++Index;
  }
 
  llvm::stable_sort(
      Options, [](const CodeGenFunction::MultiVersionResolverOption &LHS,
                  const CodeGenFunction::MultiVersionResolverOption &RHS) {
        return llvm::X86::getCpuSupportsMask(LHS.Conditions.Features) >
               llvm::X86::getCpuSupportsMask(RHS.Conditions.Features);
      });
 
  // If the list contains multiple 'default' versions, such as when it contains
  // 'pentium' and 'generic', don't emit the call to the generic one (since we
  // always run on at least a 'pentium'). We do this by deleting the 'least
  // advanced' (read, lowest mangling letter).
  while (Options.size() > 1 &&
         llvm::all_of(llvm::X86::getCpuSupportsMask(
                          (Options.end() - 2)->Conditions.Features),
                      [](auto X) { return X == 0; })) {
    StringRef LHSName = (Options.end() - 2)->Function->getName();
    StringRef RHSName = (Options.end() - 1)->Function->getName();
    if (LHSName.compare(RHSName) < 0)
      Options.erase(Options.end() - 2);
    else
      Options.erase(Options.end() - 1);
  }
 
  CodeGenFunction CGF(*this);
  CGF.EmitMultiVersionResolver(ResolverFunc, Options);
 
  if (getTarget().supportsIFunc()) {
    llvm::GlobalValue::LinkageTypes Linkage = getMultiversionLinkage(*this, GD);
    auto *IFunc = cast<llvm::GlobalValue>(GetOrCreateMultiVersionResolver(GD));
 
    // Fix up function declarations that were created for cpu_specific before
    // cpu_dispatch was known
    if (!isa<llvm::GlobalIFunc>(IFunc)) {
      assert(cast<llvm::Function>(IFunc)->isDeclaration());
      auto *GI = llvm::GlobalIFunc::create(DeclTy, 0, Linkage, "", ResolverFunc,
                                           &getModule());
      GI->takeName(IFunc);
      IFunc->replaceAllUsesWith(GI);
      IFunc->eraseFromParent();
      IFunc = GI;
    }
 
    std::string AliasName = getMangledNameImpl(
        *this, GD, FD, /*OmitMultiVersionMangling=*/true);
    llvm::Constant *AliasFunc = GetGlobalValue(AliasName);
    if (!AliasFunc) {
      auto *GA = llvm::GlobalAlias::create(DeclTy, 0, Linkage, AliasName, IFunc,
                                           &getModule());
      SetCommonAttributes(GD, GA);
    }
  }
}
 
/// If a dispatcher for the specified mangled name is not in the module, create
/// and return an llvm Function with the specified type.
llvm::Constant *CodeGenModule::GetOrCreateMultiVersionResolver(GlobalDecl GD) {
  const auto *FD = cast<FunctionDecl>(GD.getDecl());
  assert(FD && "Not a FunctionDecl?");
 
  std::string MangledName =
      getMangledNameImpl(*this, GD, FD, /*OmitMultiVersionMangling=*/true);
 
  // Holds the name of the resolver, in ifunc mode this is the ifunc (which has
  // a separate resolver).
  std::string ResolverName = MangledName;
  if (getTarget().supportsIFunc())
    ResolverName += ".ifunc";
  else if (FD->isTargetMultiVersion())
    ResolverName += ".resolver";
 
  // If the resolver has already been created, just return it.
  if (llvm::GlobalValue *ResolverGV = GetGlobalValue(ResolverName))
    return ResolverGV;
 
  const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
  llvm::FunctionType *DeclTy = getTypes().GetFunctionType(FI);
 
  // The resolver needs to be created. For target and target_clones, defer
  // creation until the end of the TU.
  if (FD->isTargetMultiVersion() || FD->isTargetClonesMultiVersion())
    MultiVersionFuncs.push_back(GD);
 
  // For cpu_specific, don't create an ifunc yet because we don't know if the
  // cpu_dispatch will be emitted in this translation unit.
  if (getTarget().supportsIFunc() && !FD->isCPUSpecificMultiVersion()) {
    llvm::Type *ResolverType = llvm::FunctionType::get(
        llvm::PointerType::get(DeclTy,
                               getTypes().getTargetAddressSpace(FD->getType())),
        false);
    llvm::Constant *Resolver = GetOrCreateLLVMFunction(
        MangledName + ".resolver", ResolverType, GlobalDecl{},
        /*ForVTable=*/false);
    llvm::GlobalIFunc *GIF =
        llvm::GlobalIFunc::create(DeclTy, 0, getMultiversionLinkage(*this, GD),
                                  "", Resolver, &getModule());
    GIF->setName(ResolverName);
    SetCommonAttributes(FD, GIF);
 
    return GIF;
  }
 
  llvm::Constant *Resolver = GetOrCreateLLVMFunction(
      ResolverName, DeclTy, GlobalDecl{}, /*ForVTable=*/false);
  assert(isa<llvm::GlobalValue>(Resolver) &&
         "Resolver should be created for the first time");
  SetCommonAttributes(FD, cast<llvm::GlobalValue>(Resolver));
  return Resolver;
}
 
/// GetOrCreateLLVMFunction - If the specified mangled name is not in the
/// module, create and return an llvm Function with the specified type. If there
/// is something in the module with the specified name, return it potentially
/// bitcasted to the right type.
///
/// If D is non-null, it specifies a decl that correspond to this.  This is used
/// to set the attributes on the function when it is first created.
llvm::Constant *CodeGenModule::GetOrCreateLLVMFunction(
    StringRef MangledName, llvm::Type *Ty, GlobalDecl GD, bool ForVTable,
    bool DontDefer, bool IsThunk, llvm::AttributeList ExtraAttrs,
    ForDefinition_t IsForDefinition) {
  const Decl *D = GD.getDecl();
 
  // Any attempts to use a MultiVersion function should result in retrieving
  // the iFunc instead. Name Mangling will handle the rest of the changes.
  if (const FunctionDecl *FD = cast_or_null<FunctionDecl>(D)) {
    // For the device mark the function as one that should be emitted.
    if (getLangOpts().OpenMPIsTargetDevice && OpenMPRuntime &&
        !OpenMPRuntime->markAsGlobalTarget(GD) && FD->isDefined() &&
        !DontDefer && !IsForDefinition) {
      if (const FunctionDecl *FDDef = FD->getDefinition()) {
        GlobalDecl GDDef;
        if (const auto *CD = dyn_cast<CXXConstructorDecl>(FDDef))
          GDDef = GlobalDecl(CD, GD.getCtorType());
        else if (const auto *DD = dyn_cast<CXXDestructorDecl>(FDDef))
          GDDef = GlobalDecl(DD, GD.getDtorType());
        else
          GDDef = GlobalDecl(FDDef);
        EmitGlobal(GDDef);
      }
    }
 
    if (FD->isMultiVersion()) {
      UpdateMultiVersionNames(GD, FD, MangledName);
      if (!IsForDefinition)
        return GetOrCreateMultiVersionResolver(GD);
    }
  }
 
  // Lookup the entry, lazily creating it if necessary.
  llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
  if (Entry) {
    if (WeakRefReferences.erase(Entry)) {
      const FunctionDecl *FD = cast_or_null<FunctionDecl>(D);
      if (FD && !FD->hasAttr<WeakAttr>())
        Entry->setLinkage(llvm::Function::ExternalLinkage);
    }
 
    // Handle dropped DLL attributes.
    if (D && !D->hasAttr<DLLImportAttr>() && !D->hasAttr<DLLExportAttr>() &&
        !shouldMapVisibilityToDLLExport(cast_or_null<NamedDecl>(D))) {
      Entry->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
      setDSOLocal(Entry);
    }
 
    // If there are two attempts to define the same mangled name, issue an
    // error.
    if (IsForDefinition && !Entry->isDeclaration()) {
      GlobalDecl OtherGD;
      // Check that GD is not yet in DiagnosedConflictingDefinitions is required
      // to make sure that we issue an error only once.
      if (lookupRepresentativeDecl(MangledName, OtherGD) &&
          (GD.getCanonicalDecl().getDecl() !=
           OtherGD.getCanonicalDecl().getDecl()) &&
          DiagnosedConflictingDefinitions.insert(GD).second) {
        getDiags().Report(D->getLocation(), diag::err_duplicate_mangled_name)
            << MangledName;
        getDiags().Report(OtherGD.getDecl()->getLocation(),
                          diag::note_previous_definition);
      }
    }
 
    if ((isa<llvm::Function>(Entry) || isa<llvm::GlobalAlias>(Entry)) &&
        (Entry->getValueType() == Ty)) {
      return Entry;
    }
 
    // Make sure the result is of the correct type.
    // (If function is requested for a definition, we always need to create a new
    // function, not just return a bitcast.)
    if (!IsForDefinition)
      return Entry;
  }
 
  // This function doesn't have a complete type (for example, the return
  // type is an incomplete struct). Use a fake type instead, and make
  // sure not to try to set attributes.
  bool IsIncompleteFunction = false;
 
  llvm::FunctionType *FTy;
  if (isa<llvm::FunctionType>(Ty)) {
    FTy = cast<llvm::FunctionType>(Ty);
  } else {
    FTy = llvm::FunctionType::get(VoidTy, false);
    IsIncompleteFunction = true;
  }
 
  llvm::Function *F =
      llvm::Function::Create(FTy, llvm::Function::ExternalLinkage,
                             Entry ? StringRef() : MangledName, &getModule());
 
  // If we already created a function with the same mangled name (but different
  // type) before, take its name and add it to the list of functions to be
  // replaced with F at the end of CodeGen.
  //
  // This happens if there is a prototype for a function (e.g. "int f()") and
  // then a definition of a different type (e.g. "int f(int x)").
  if (Entry) {
    F->takeName(Entry);
 
    // This might be an implementation of a function without a prototype, in
    // which case, try to do special replacement of calls which match the new
    // prototype.  The really key thing here is that we also potentially drop
    // arguments from the call site so as to make a direct call, which makes the
    // inliner happier and suppresses a number of optimizer warnings (!) about
    // dropping arguments.
    if (!Entry->use_empty()) {
      ReplaceUsesOfNonProtoTypeWithRealFunction(Entry, F);
      Entry->removeDeadConstantUsers();
    }
 
    addGlobalValReplacement(Entry, F);
  }
 
  assert(F->getName() == MangledName && "name was uniqued!");
  if (D)
    SetFunctionAttributes(GD, F, IsIncompleteFunction, IsThunk);
  if (ExtraAttrs.hasFnAttrs()) {
    llvm::AttrBuilder B(F->getContext(), ExtraAttrs.getFnAttrs());
    F->addFnAttrs(B);
  }
 
  if (!DontDefer) {
    // All MSVC dtors other than the base dtor are linkonce_odr and delegate to
    // each other bottoming out with the base dtor.  Therefore we emit non-base
    // dtors on usage, even if there is no dtor definition in the TU.
    if (isa_and_nonnull<CXXDestructorDecl>(D) &&
        getCXXABI().useThunkForDtorVariant(cast<CXXDestructorDecl>(D),
                                           GD.getDtorType()))
      addDeferredDeclToEmit(GD);
 
    // This is the first use or definition of a mangled name.  If there is a
    // deferred decl with this name, remember that we need to emit it at the end
    // of the file.
    auto DDI = DeferredDecls.find(MangledName);
    if (DDI != DeferredDecls.end()) {
      // Move the potentially referenced deferred decl to the
      // DeferredDeclsToEmit list, and remove it from DeferredDecls (since we
      // don't need it anymore).
      addDeferredDeclToEmit(DDI->second);
      DeferredDecls.erase(DDI);
 
      // Otherwise, there are cases we have to worry about where we're
      // using a declaration for which we must emit a definition but where
      // we might not find a top-level definition:
      //   - member functions defined inline in their classes
      //   - friend functions defined inline in some class
      //   - special member functions with implicit definitions
      // If we ever change our AST traversal to walk into class methods,
      // this will be unnecessary.
      //
      // We also don't emit a definition for a function if it's going to be an
      // entry in a vtable, unless it's already marked as used.
    } else if (getLangOpts().CPlusPlus && D) {
      // Look for a declaration that's lexically in a record.
      for (const auto *FD = cast<FunctionDecl>(D)->getMostRecentDecl(); FD;
           FD = FD->getPreviousDecl()) {
        if (isa<CXXRecordDecl>(FD->getLexicalDeclContext())) {
          if (FD->doesThisDeclarationHaveABody()) {
            addDeferredDeclToEmit(GD.getWithDecl(FD));
            break;
          }
        }
      }
    }
  }
 
  // Make sure the result is of the requested type.
  if (!IsIncompleteFunction) {
    assert(F->getFunctionType() == Ty);
    return F;
  }
 
  return F;
}
 
/// GetAddrOfFunction - Return the address of the given function.  If Ty is
/// non-null, then this function will use the specified type if it has to
/// create it (this occurs when we see a definition of the function).
llvm::Constant *
CodeGenModule::GetAddrOfFunction(GlobalDecl GD, llvm::Type *Ty, bool ForVTable,
                                 bool DontDefer,
                                 ForDefinition_t IsForDefinition) {
  // If there was no specific requested type, just convert it now.
  if (!Ty) {
    const auto *FD = cast<FunctionDecl>(GD.getDecl());
    Ty = getTypes().ConvertType(FD->getType());
  }
 
  // Devirtualized destructor calls may come through here instead of via
  // getAddrOfCXXStructor. Make sure we use the MS ABI base destructor instead
  // of the complete destructor when necessary.
  if (const auto *DD = dyn_cast<CXXDestructorDecl>(GD.getDecl())) {
    if (getTarget().getCXXABI().isMicrosoft() &&
        GD.getDtorType() == Dtor_Complete &&
        DD->getParent()->getNumVBases() == 0)
      GD = GlobalDecl(DD, Dtor_Base);
  }
 
  StringRef MangledName = getMangledName(GD);
  auto *F = GetOrCreateLLVMFunction(MangledName, Ty, GD, ForVTable, DontDefer,
                                    /*IsThunk=*/false, llvm::AttributeList(),
                                    IsForDefinition);
  // Returns kernel handle for HIP kernel stub function.
  if (LangOpts.CUDA && !LangOpts.CUDAIsDevice &&
      cast<FunctionDecl>(GD.getDecl())->hasAttr<CUDAGlobalAttr>()) {
    auto *Handle = getCUDARuntime().getKernelHandle(
        cast<llvm::Function>(F->stripPointerCasts()), GD);
    if (IsForDefinition)
      return F;
    return Handle;
  }
  return F;
}
 
llvm::Constant *CodeGenModule::GetFunctionStart(const ValueDecl *Decl) {
  llvm::GlobalValue *F =
      cast<llvm::GlobalValue>(GetAddrOfFunction(Decl)->stripPointerCasts());
 
  return llvm::ConstantExpr::getBitCast(
      llvm::NoCFIValue::get(F),
      llvm::PointerType::get(VMContext, F->getAddressSpace()));
}
 
static const FunctionDecl *
GetRuntimeFunctionDecl(ASTContext &C, StringRef Name) {
  TranslationUnitDecl *TUDecl = C.getTranslationUnitDecl();
  DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl);
 
  IdentifierInfo &CII = C.Idents.get(Name);
  for (const auto *Result : DC->lookup(&CII))
    if (const auto *FD = dyn_cast<FunctionDecl>(Result))
      return FD;
 
  if (!C.getLangOpts().CPlusPlus)
    return nullptr;
 
  // Demangle the premangled name from getTerminateFn()
  IdentifierInfo &CXXII =
      (Name == "_ZSt9terminatev" || Name == "?terminate@@YAXXZ")
          ? C.Idents.get("terminate")
          : C.Idents.get(Name);
 
  for (const auto &N : {"__cxxabiv1", "std"}) {
    IdentifierInfo &NS = C.Idents.get(N);
    for (const auto *Result : DC->lookup(&NS)) {
      const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(Result);
      if (auto *LSD = dyn_cast<LinkageSpecDecl>(Result))
        for (const auto *Result : LSD->lookup(&NS))
          if ((ND = dyn_cast<NamespaceDecl>(Result)))
            break;
 
      if (ND)
        for (const auto *Result : ND->lookup(&CXXII))
          if (const auto *FD = dyn_cast<FunctionDecl>(Result))
            return FD;
    }
  }
 
  return nullptr;
}
 
/// CreateRuntimeFunction - Create a new runtime function with the specified
/// type and name.
llvm::FunctionCallee
CodeGenModule::CreateRuntimeFunction(llvm::FunctionType *FTy, StringRef Name,
                                     llvm::AttributeList ExtraAttrs, bool Local,
                                     bool AssumeConvergent) {
  if (AssumeConvergent) {
    ExtraAttrs =
        ExtraAttrs.addFnAttribute(VMContext, llvm::Attribute::Convergent);
  }
 
  llvm::Constant *C =
      GetOrCreateLLVMFunction(Name, FTy, GlobalDecl(), /*ForVTable=*/false,
                              /*DontDefer=*/false, /*IsThunk=*/false,
                              ExtraAttrs);
 
  if (auto *F = dyn_cast<llvm::Function>(C)) {
    if (F->empty()) {
      F->setCallingConv(getRuntimeCC());
 
      // In Windows Itanium environments, try to mark runtime functions
      // dllimport. For Mingw and MSVC, don't. We don't really know if the user
      // will link their standard library statically or dynamically. Marking
      // functions imported when they are not imported can cause linker errors
      // and warnings.
      if (!Local && getTriple().isWindowsItaniumEnvironment() &&
          !getCodeGenOpts().LTOVisibilityPublicStd) {
        const FunctionDecl *FD = GetRuntimeFunctionDecl(Context, Name);
        if (!FD || FD->hasAttr<DLLImportAttr>()) {
          F->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
          F->setLinkage(llvm::GlobalValue::ExternalLinkage);
        }
      }
      setDSOLocal(F);
    }
  }
 
  return {FTy, C};
}
 
/// GetOrCreateLLVMGlobal - If the specified mangled name is not in the module,
/// create and return an llvm GlobalVariable with the specified type and address
/// space. If there is something in the module with the specified name, return
/// it potentially bitcasted to the right type.
///
/// If D is non-null, it specifies a decl that correspond to this.  This is used
/// to set the attributes on the global when it is first created.
///
/// If IsForDefinition is true, it is guaranteed that an actual global with
/// type Ty will be returned, not conversion of a variable with the same
/// mangled name but some other type.
llvm::Constant *
CodeGenModule::GetOrCreateLLVMGlobal(StringRef MangledName, llvm::Type *Ty,
                                     LangAS AddrSpace, const VarDecl *D,
                                     ForDefinition_t IsForDefinition) {
  // Lookup the entry, lazily creating it if necessary.
  llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
  unsigned TargetAS = getContext().getTargetAddressSpace(AddrSpace);
  if (Entry) {
    if (WeakRefReferences.erase(Entry)) {
      if (D && !D->hasAttr<WeakAttr>())
        Entry->setLinkage(llvm::Function::ExternalLinkage);
    }
 
    // Handle dropped DLL attributes.
    if (D && !D->hasAttr<DLLImportAttr>() && !D->hasAttr<DLLExportAttr>() &&
        !shouldMapVisibilityToDLLExport(D))
      Entry->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
 
    if (LangOpts.OpenMP && !LangOpts.OpenMPSimd && D)
      getOpenMPRuntime().registerTargetGlobalVariable(D, Entry);
 
    if (Entry->getValueType() == Ty && Entry->getAddressSpace() == TargetAS)
      return Entry;
 
    // If there are two attempts to define the same mangled name, issue an
    // error.
    if (IsForDefinition && !Entry->isDeclaration()) {
      GlobalDecl OtherGD;
      const VarDecl *OtherD;
 
      // Check that D is not yet in DiagnosedConflictingDefinitions is required
      // to make sure that we issue an error only once.
      if (D && lookupRepresentativeDecl(MangledName, OtherGD) &&
          (D->getCanonicalDecl() != OtherGD.getCanonicalDecl().getDecl()) &&
          (OtherD = dyn_cast<VarDecl>(OtherGD.getDecl())) &&
          OtherD->hasInit() &&
          DiagnosedConflictingDefinitions.insert(D).second) {
        getDiags().Report(D->getLocation(), diag::err_duplicate_mangled_name)
            << MangledName;
        getDiags().Report(OtherGD.getDecl()->getLocation(),
                          diag::note_previous_definition);
      }
    }
 
    // Make sure the result is of the correct type.
    if (Entry->getType()->getAddressSpace() != TargetAS)
      return llvm::ConstantExpr::getAddrSpaceCast(
          Entry, llvm::PointerType::get(Ty->getContext(), TargetAS));
 
    // (If global is requested for a definition, we always need to create a new
    // global, not just return a bitcast.)
    if (!IsForDefinition)
      return Entry;
  }
 
  auto DAddrSpace = GetGlobalVarAddressSpace(D);
 
  auto *GV = new llvm::GlobalVariable(
      getModule(), Ty, false, llvm::GlobalValue::ExternalLinkage, nullptr,
      MangledName, nullptr, llvm::GlobalVariable::NotThreadLocal,
      getContext().getTargetAddressSpace(DAddrSpace));
 
  // If we already created a global with the same mangled name (but different
  // type) before, take its name and remove it from its parent.
  if (Entry) {
    GV->takeName(Entry);
 
    if (!Entry->use_empty()) {
      llvm::Constant *NewPtrForOldDecl =
          llvm::ConstantExpr::getBitCast(GV, Entry->getType());
      Entry->replaceAllUsesWith(NewPtrForOldDecl);
    }
 
    Entry->eraseFromParent();
  }
 
  // This is the first use or definition of a mangled name.  If there is a
  // deferred decl with this name, remember that we need to emit it at the end
  // of the file.
  auto DDI = DeferredDecls.find(MangledName);
  if (DDI != DeferredDecls.end()) {
    // Move the potentially referenced deferred decl to the DeferredDeclsToEmit
    // list, and remove it from DeferredDecls (since we don't need it anymore).
    addDeferredDeclToEmit(DDI->second);
    DeferredDecls.erase(DDI);
  }
 
  // Handle things which are present even on external declarations.
  if (D) {
    if (LangOpts.OpenMP && !LangOpts.OpenMPSimd)
      getOpenMPRuntime().registerTargetGlobalVariable(D, GV);
 
    // FIXME: This code is overly simple and should be merged with other global
    // handling.
    GV->setConstant(D->getType().isConstantStorage(getContext(), false, false));
 
    GV->setAlignment(getContext().getDeclAlign(D).getAsAlign());
 
    setLinkageForGV(GV, D);
 
    if (D->getTLSKind()) {
      if (D->getTLSKind() == VarDecl::TLS_Dynamic)
        CXXThreadLocals.push_back(D);
      setTLSMode(GV, *D);
    }
 
    setGVProperties(GV, D);
 
    // If required by the ABI, treat declarations of static data members with
    // inline initializers as definitions.
    if (getContext().isMSStaticDataMemberInlineDefinition(D)) {
      EmitGlobalVarDefinition(D);
    }
 
    // Emit section information for extern variables.
    if (D->hasExternalStorage()) {
      if (const SectionAttr *SA = D->getAttr<SectionAttr>())
        GV->setSection(SA->getName());
    }
 
    // Handle XCore specific ABI requirements.
    if (getTriple().getArch() == llvm::Triple::xcore &&
        D->getLanguageLinkage() == CLanguageLinkage &&
        D->getType().isConstant(Context) &&
        isExternallyVisible(D->getLinkageAndVisibility().getLinkage()))
      GV->setSection(".cp.rodata");
 
    // Check if we a have a const declaration with an initializer, we may be
    // able to emit it as available_externally to expose it's value to the
    // optimizer.
    if (Context.getLangOpts().CPlusPlus && GV->hasExternalLinkage() &&
        D->getType().isConstQualified() && !GV->hasInitializer() &&
        !D->hasDefinition() && D->hasInit() && !D->hasAttr<DLLImportAttr>()) {
      const auto *Record =
          Context.getBaseElementType(D->getType())->getAsCXXRecordDecl();
      bool HasMutableFields = Record && Record->hasMutableFields();
      if (!HasMutableFields) {
        const VarDecl *InitDecl;
        const Expr *InitExpr = D->getAnyInitializer(InitDecl);
        if (InitExpr) {
          ConstantEmitter emitter(*this);
          llvm::Constant *Init = emitter.tryEmitForInitializer(*InitDecl);
          if (Init) {
            auto *InitType = Init->getType();
            if (GV->getValueType() != InitType) {
              // The type of the initializer does not match the definition.
              // This happens when an initializer has a different type from
              // the type of the global (because of padding at the end of a
              // structure for instance).
              GV->setName(StringRef());
              // Make a new global with the correct type, this is now guaranteed
              // to work.
              auto *NewGV = cast<llvm::GlobalVariable>(
                  GetAddrOfGlobalVar(D, InitType, IsForDefinition)
                      ->stripPointerCasts());
 
              // Erase the old global, since it is no longer used.
              GV->eraseFromParent();
              GV = NewGV;
            } else {
              GV->setInitializer(Init);
              GV->setConstant(true);
              GV->setLinkage(llvm::GlobalValue::AvailableExternallyLinkage);
            }
            emitter.finalize(GV);
          }
        }
      }
    }
  }
 
  if (D &&
      D->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly) {
    getTargetCodeGenInfo().setTargetAttributes(D, GV, *this);
    // External HIP managed variables needed to be recorded for transformation
    // in both device and host compilations.
    if (getLangOpts().CUDA && D && D->hasAttr<HIPManagedAttr>() &&
        D->hasExternalStorage())
      getCUDARuntime().handleVarRegistration(D, *GV);
  }
 
  if (D)
    SanitizerMD->reportGlobal(GV, *D);
 
  LangAS ExpectedAS =
      D ? D->getType().getAddressSpace()
        : (LangOpts.OpenCL ? LangAS::opencl_global : LangAS::Default);
  assert(getContext().getTargetAddressSpace(ExpectedAS) == TargetAS);
  if (DAddrSpace != ExpectedAS) {
    return getTargetCodeGenInfo().performAddrSpaceCast(
        *this, GV, DAddrSpace, ExpectedAS, Ty->getPointerTo(TargetAS));
  }
 
  return GV;
}
 
llvm::Constant *
CodeGenModule::GetAddrOfGlobal(GlobalDecl GD, ForDefinition_t IsForDefinition) {
  const Decl *D = GD.getDecl();
 
  if (isa<CXXConstructorDecl>(D) || isa<CXXDestructorDecl>(D))
    return getAddrOfCXXStructor(GD, /*FnInfo=*/nullptr, /*FnType=*/nullptr,
                                /*DontDefer=*/false, IsForDefinition);
 
  if (isa<CXXMethodDecl>(D)) {
    auto FInfo =
        &getTypes().arrangeCXXMethodDeclaration(cast<CXXMethodDecl>(D));
    auto Ty = getTypes().GetFunctionType(*FInfo);
    return GetAddrOfFunction(GD, Ty, /*ForVTable=*/false, /*DontDefer=*/false,
                             IsForDefinition);
  }
 
  if (isa<FunctionDecl>(D)) {
    const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
    llvm::FunctionType *Ty = getTypes().GetFunctionType(FI);
    return GetAddrOfFunction(GD, Ty, /*ForVTable=*/false, /*DontDefer=*/false,
                             IsForDefinition);
  }
 
  return GetAddrOfGlobalVar(cast<VarDecl>(D), /*Ty=*/nullptr, IsForDefinition);
}
 
llvm::GlobalVariable *CodeGenModule::CreateOrReplaceCXXRuntimeVariable(
    StringRef Name, llvm::Type *Ty, llvm::GlobalValue::LinkageTypes Linkage,
    llvm::Align Alignment) {
  llvm::GlobalVariable *GV = getModule().getNamedGlobal(Name);
  llvm::GlobalVariable *OldGV = nullptr;
 
  if (GV) {
    // Check if the variable has the right type.
    if (GV->getValueType() == Ty)
      return GV;
 
    // Because C++ name mangling, the only way we can end up with an already
    // existing global with the same name is if it has been declared extern "C".
    assert(GV->isDeclaration() && "Declaration has wrong type!");
    OldGV = GV;
  }
 
  // Create a new variable.
  GV = new llvm::GlobalVariable(getModule(), Ty, /*isConstant=*/true,
                                Linkage, nullptr, Name);
 
  if (OldGV) {
    // Replace occurrences of the old variable if needed.
    GV->takeName(OldGV);
 
    if (!OldGV->use_empty()) {
      llvm::Constant *NewPtrForOldDecl =
      llvm::ConstantExpr::getBitCast(GV, OldGV->getType());
      OldGV->replaceAllUsesWith(NewPtrForOldDecl);
    }
 
    OldGV->eraseFromParent();
  }
 
  if (supportsCOMDAT() && GV->isWeakForLinker() &&
      !GV->hasAvailableExternallyLinkage())
    GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
 
  GV->setAlignment(Alignment);
 
  return GV;
}
 
/// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the
/// given global variable.  If Ty is non-null and if the global doesn't exist,
/// then it will be created with the specified type instead of whatever the
/// normal requested type would be. If IsForDefinition is true, it is guaranteed
/// that an actual global with type Ty will be returned, not conversion of a
/// variable with the same mangled name but some other type.
llvm::Constant *CodeGenModule::GetAddrOfGlobalVar(const VarDecl *D,
                                                  llvm::Type *Ty,
                                           ForDefinition_t IsForDefinition) {
  assert(D->hasGlobalStorage() && "Not a global variable");
  QualType ASTTy = D->getType();
  if (!Ty)
    Ty = getTypes().ConvertTypeForMem(ASTTy);
 
  StringRef MangledName = getMangledName(D);
  return GetOrCreateLLVMGlobal(MangledName, Ty, ASTTy.getAddressSpace(), D,
                               IsForDefinition);
}
 
/// CreateRuntimeVariable - Create a new runtime global variable with the
/// specified type and name.
llvm::Constant *
CodeGenModule::CreateRuntimeVariable(llvm::Type *Ty,
                                     StringRef Name) {
  LangAS AddrSpace = getContext().getLangOpts().OpenCL ? LangAS::opencl_global
                                                       : LangAS::Default;
  auto *Ret = GetOrCreateLLVMGlobal(Name, Ty, AddrSpace, nullptr);
  setDSOLocal(cast<llvm::GlobalValue>(Ret->stripPointerCasts()));
  return Ret;
}
 
void CodeGenModule::EmitTentativeDefinition(const VarDecl *D) {
  assert(!D->getInit() && "Cannot emit definite definitions here!");
 
  StringRef MangledName = getMangledName(D);
  llvm::GlobalValue *GV = GetGlobalValue(MangledName);
 
  // We already have a definition, not declaration, with the same mangled name.
  // Emitting of declaration is not required (and actually overwrites emitted
  // definition).
  if (GV && !GV->isDeclaration())
    return;
 
  // If we have not seen a reference to this variable yet, place it into the
  // deferred declarations table to be emitted if needed later.
  if (!MustBeEmitted(D) && !GV) {
      DeferredDecls[MangledName] = D;
      return;
  }
 
  // The tentative definition is the only definition.
  EmitGlobalVarDefinition(D);
}
 
void CodeGenModule::EmitExternalDeclaration(const VarDecl *D) {
  EmitExternalVarDeclaration(D);
}
 
CharUnits CodeGenModule::GetTargetTypeStoreSize(llvm::Type *Ty) const {
  return Context.toCharUnitsFromBits(
      getDataLayout().getTypeStoreSizeInBits(Ty));
}
 
LangAS CodeGenModule::GetGlobalVarAddressSpace(const VarDecl *D) {
  if (LangOpts.OpenCL) {
    LangAS AS = D ? D->getType().getAddressSpace() : LangAS::opencl_global;
    assert(AS == LangAS::opencl_global ||
           AS == LangAS::opencl_global_device ||
           AS == LangAS::opencl_global_host ||
           AS == LangAS::opencl_constant ||
           AS == LangAS::opencl_local ||
           AS >= LangAS::FirstTargetAddressSpace);
    return AS;
  }
 
  if (LangOpts.SYCLIsDevice &&
      (!D || D->getType().getAddressSpace() == LangAS::Default))
    return LangAS::sycl_global;
 
  if (LangOpts.CUDA && LangOpts.CUDAIsDevice) {
    if (D) {
      if (D->hasAttr<CUDAConstantAttr>())
        return LangAS::cuda_constant;
      if (D->hasAttr<CUDASharedAttr>())
        return LangAS::cuda_shared;
      if (D->hasAttr<CUDADeviceAttr>())
        return LangAS::cuda_device;
      if (D->getType().isConstQualified())
        return LangAS::cuda_constant;
    }
    return LangAS::cuda_device;
  }
 
  if (LangOpts.OpenMP) {
    LangAS AS;
    if (OpenMPRuntime->hasAllocateAttributeForGlobalVar(D, AS))
      return AS;
  }
  return getTargetCodeGenInfo().getGlobalVarAddressSpace(*this, D);
}
 
LangAS CodeGenModule::GetGlobalConstantAddressSpace() const {
  // OpenCL v1.2 s6.5.3: a string literal is in the constant address space.
  if (LangOpts.OpenCL)
    return LangAS::opencl_constant;
  if (LangOpts.SYCLIsDevice)
    return LangAS::sycl_global;
  if (LangOpts.HIP && LangOpts.CUDAIsDevice && getTriple().isSPIRV())
    // For HIPSPV map literals to cuda_device (maps to CrossWorkGroup in SPIR-V)
    // instead of default AS (maps to Generic in SPIR-V). Otherwise, we end up
    // with OpVariable instructions with Generic storage class which is not
    // allowed (SPIR-V V1.6 s3.42.8). Also, mapping literals to SPIR-V
    // UniformConstant storage class is not viable as pointers to it may not be
    // casted to Generic pointers which are used to model HIP's "flat" pointers.
    return LangAS::cuda_device;
  if (auto AS = getTarget().getConstantAddressSpace())
    return *AS;
  return LangAS::Default;
}
 
// In address space agnostic languages, string literals are in default address
// space in AST. However, certain targets (e.g. amdgcn) request them to be
// emitted in constant address space in LLVM IR. To be consistent with other
// parts of AST, string literal global variables in constant address space
// need to be casted to default address space before being put into address
// map and referenced by other part of CodeGen.
// In OpenCL, string literals are in constant address space in AST, therefore
// they should not be casted to default address space.
static llvm::Constant *
castStringLiteralToDefaultAddressSpace(CodeGenModule &CGM,
                                       llvm::GlobalVariable *GV) {
  llvm::Constant *Cast = GV;
  if (!CGM.getLangOpts().OpenCL) {
    auto AS = CGM.GetGlobalConstantAddressSpace();
    if (AS != LangAS::Default)
      Cast = CGM.getTargetCodeGenInfo().performAddrSpaceCast(
          CGM, GV, AS, LangAS::Default,
          GV->getValueType()->getPointerTo(
              CGM.getContext().getTargetAddressSpace(LangAS::Default)));
  }
  return Cast;
}
 
template<typename SomeDecl>
void CodeGenModule::MaybeHandleStaticInExternC(const SomeDecl *D,
                                               llvm::GlobalValue *GV) {
  if (!getLangOpts().CPlusPlus)
    return;
 
  // Must have 'used' attribute, or else inline assembly can't rely on
  // the name existing.
  if (!D->template hasAttr<UsedAttr>())
    return;
 
  // Must have internal linkage and an ordinary name.
  if (!D->getIdentifier() || D->getFormalLinkage() != InternalLinkage)
    return;
 
  // Must be in an extern "C" context. Entities declared directly within
  // a record are not extern "C" even if the record is in such a context.
  const SomeDecl *First = D->getFirstDecl();
  if (First->getDeclContext()->isRecord() || !First->isInExternCContext())
    return;
 
  // OK, this is an internal linkage entity inside an extern "C" linkage
  // specification. Make a note of that so we can give it the "expected"
  // mangled name if nothing else is using that name.
  std::pair<StaticExternCMap::iterator, bool> R =
      StaticExternCValues.insert(std::make_pair(D->getIdentifier(), GV));
 
  // If we have multiple internal linkage entities with the same name
  // in extern "C" regions, none of them gets that name.
  if (!R.second)
    R.first->second = nullptr;
}
 
static bool shouldBeInCOMDAT(CodeGenModule &CGM, const Decl &D) {
  if (!CGM.supportsCOMDAT())
    return false;
 
  if (D.hasAttr<SelectAnyAttr>())
    return true;
 
  GVALinkage Linkage;
  if (auto *VD = dyn_cast<VarDecl>(&D))
    Linkage = CGM.getContext().GetGVALinkageForVariable(VD);
  else
    Linkage = CGM.getContext().GetGVALinkageForFunction(cast<FunctionDecl>(&D));
 
  switch (Linkage) {
  case GVA_Internal:
  case GVA_AvailableExternally:
  case GVA_StrongExternal:
    return false;
  case GVA_DiscardableODR:
  case GVA_StrongODR:
    return true;
  }
  llvm_unreachable("No such linkage");
}
 
bool CodeGenModule::supportsCOMDAT() const {
  return getTriple().supportsCOMDAT();
}
 
void CodeGenModule::maybeSetTrivialComdat(const Decl &D,
                                          llvm::GlobalObject &GO) {
  if (!shouldBeInCOMDAT(*this, D))
    return;
  GO.setComdat(TheModule.getOrInsertComdat(GO.getName()));
}
 
/// Pass IsTentative as true if you want to create a tentative definition.
void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D,
                                            bool IsTentative) {
  // OpenCL global variables of sampler type are translated to function calls,
  // therefore no need to be translated.
  QualType ASTTy = D->getType();
  if (getLangOpts().OpenCL && ASTTy->isSamplerT())
    return;
 
  // If this is OpenMP device, check if it is legal to emit this global
  // normally.
  if (LangOpts.OpenMPIsTargetDevice && OpenMPRuntime &&
      OpenMPRuntime->emitTargetGlobalVariable(D))
    return;
 
  llvm::TrackingVH<llvm::Constant> Init;
  bool NeedsGlobalCtor = false;
  // Whether the definition of the variable is available externally.
  // If yes, we shouldn't emit the GloablCtor and GlobalDtor for the variable
  // since this is the job for its original source.
  bool IsDefinitionAvailableExternally =
      getContext().GetGVALinkageForVariable(D) == GVA_AvailableExternally;
  bool NeedsGlobalDtor =
      !IsDefinitionAvailableExternally &&
      D->needsDestruction(getContext()) == QualType::DK_cxx_destructor;
 
  const VarDecl *InitDecl;
  const Expr *InitExpr = D->getAnyInitializer(InitDecl);
 
  std::optional<ConstantEmitter> emitter;
 
  // CUDA E.2.4.1 "__shared__ variables cannot have an initialization
  // as part of their declaration."  Sema has already checked for
  // error cases, so we just need to set Init to UndefValue.
  bool IsCUDASharedVar =
      getLangOpts().CUDAIsDevice && D->hasAttr<CUDASharedAttr>();
  // Shadows of initialized device-side global variables are also left
  // undefined.
  // Managed Variables should be initialized on both host side and device side.
  bool IsCUDAShadowVar =
      !getLangOpts().CUDAIsDevice && !D->hasAttr<HIPManagedAttr>() &&
      (D->hasAttr<CUDAConstantAttr>() || D->hasAttr<CUDADeviceAttr>() ||
       D->hasAttr<CUDASharedAttr>());
  bool IsCUDADeviceShadowVar =
      getLangOpts().CUDAIsDevice && !D->hasAttr<HIPManagedAttr>() &&
      (D->getType()->isCUDADeviceBuiltinSurfaceType() ||
       D->getType()->isCUDADeviceBuiltinTextureType());
  if (getLangOpts().CUDA &&
      (IsCUDASharedVar || IsCUDAShadowVar || IsCUDADeviceShadowVar))
    Init = llvm::UndefValue::get(getTypes().ConvertTypeForMem(ASTTy));
  else if (D->hasAttr<LoaderUninitializedAttr>())
    Init = llvm::UndefValue::get(getTypes().ConvertTypeForMem(ASTTy));
  else if (!InitExpr) {
    // This is a tentative definition; tentative definitions are
    // implicitly initialized with { 0 }.
    //
    // Note that tentative definitions are only emitted at the end of
    // a translation unit, so they should never have incomplete
    // type. In addition, EmitTentativeDefinition makes sure that we
    // never attempt to emit a tentative definition if a real one
    // exists. A use may still exists, however, so we still may need
    // to do a RAUW.
    assert(!ASTTy->isIncompleteType() && "Unexpected incomplete type");
    Init = EmitNullConstant(D->getType());
  } else {
    initializedGlobalDecl = GlobalDecl(D);
    emitter.emplace(*this);
    llvm::Constant *Initializer = emitter->tryEmitForInitializer(*InitDecl);
    if (!Initializer) {
      QualType T = InitExpr->getType();
      if (D->getType()->isReferenceType())
        T = D->getType();
 
      if (getLangOpts().CPlusPlus) {
        if (InitDecl->hasFlexibleArrayInit(getContext()))
          ErrorUnsupported(D, "flexible array initializer");
        Init = EmitNullConstant(T);
 
        if (!IsDefinitionAvailableExternally)
          NeedsGlobalCtor = true;
      } else {
        ErrorUnsupported(D, "static initializer");
        Init = llvm::UndefValue::get(getTypes().ConvertType(T));
      }
    } else {
      Init = Initializer;
      // We don't need an initializer, so remove the entry for the delayed
      // initializer position (just in case this entry was delayed) if we
      // also don't need to register a destructor.
      if (getLangOpts().CPlusPlus && !NeedsGlobalDtor)
        DelayedCXXInitPosition.erase(D);
 
#ifndef NDEBUG
      CharUnits VarSize = getContext().getTypeSizeInChars(ASTTy) +
                          InitDecl->getFlexibleArrayInitChars(getContext());
      CharUnits CstSize = CharUnits::fromQuantity(
          getDataLayout().getTypeAllocSize(Init->getType()));
      assert(VarSize == CstSize && "Emitted constant has unexpected size");
#endif
    }
  }
 
  llvm::Type* InitType = Init->getType();
  llvm::Constant *Entry =
      GetAddrOfGlobalVar(D, InitType, ForDefinition_t(!IsTentative));
 
  // Strip off pointer casts if we got them.
  Entry = Entry->stripPointerCasts();
 
  // Entry is now either a Function or GlobalVariable.
  auto *GV = dyn_cast<llvm::GlobalVariable>(Entry);
 
  // We have a definition after a declaration with the wrong type.
  // We must make a new GlobalVariable* and update everything that used OldGV
  // (a declaration or tentative definition) with the new GlobalVariable*
  // (which will be a definition).
  //
  // This happens if there is a prototype for a global (e.g.
  // "extern int x[];") and then a definition of a different type (e.g.
  // "int x[10];"). This also happens when an initializer has a different type
  // from the type of the global (this happens with unions).
  if (!GV || GV->getValueType() != InitType ||
      GV->getType()->getAddressSpace() !=
          getContext().getTargetAddressSpace(GetGlobalVarAddressSpace(D))) {
 
    // Move the old entry aside so that we'll create a new one.
    Entry->setName(StringRef());
 
    // Make a new global with the correct type, this is now guaranteed to work.
    GV = cast<llvm::GlobalVariable>(
        GetAddrOfGlobalVar(D, InitType, ForDefinition_t(!IsTentative))
            ->stripPointerCasts());
 
    // Replace all uses of the old global with the new global
    llvm::Constant *NewPtrForOldDecl =
        llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV,
                                                             Entry->getType());
    Entry->replaceAllUsesWith(NewPtrForOldDecl);
 
    // Erase the old global, since it is no longer used.
    cast<llvm::GlobalValue>(Entry)->eraseFromParent();
  }
 
  MaybeHandleStaticInExternC(D, GV);
 
  if (D->hasAttr<AnnotateAttr>())
    AddGlobalAnnotations(D, GV);
 
  // Set the llvm linkage type as appropriate.
  llvm::GlobalValue::LinkageTypes Linkage = getLLVMLinkageVarDefinition(D);
 
  // CUDA B.2.1 "The __device__ qualifier declares a variable that resides on
  // the device. [...]"
  // CUDA B.2.2 "The __constant__ qualifier, optionally used together with
  // __device__, declares a variable that: [...]
  // Is accessible from all the threads within the grid and from the host
  // through the runtime library (cudaGetSymbolAddress() / cudaGetSymbolSize()
  // / cudaMemcpyToSymbol() / cudaMemcpyFromSymbol())."
  if (LangOpts.CUDA) {
    if (LangOpts.CUDAIsDevice) {
      if (Linkage != llvm::GlobalValue::InternalLinkage &&
          (D->hasAttr<CUDADeviceAttr>() || D->hasAttr<CUDAConstantAttr>() ||
           D->getType()->isCUDADeviceBuiltinSurfaceType() ||
           D->getType()->isCUDADeviceBuiltinTextureType()))
        GV->setExternallyInitialized(true);
    } else {
      getCUDARuntime().internalizeDeviceSideVar(D, Linkage);
    }
    getCUDARuntime().handleVarRegistration(D, *GV);
  }
 
  GV->setInitializer(Init);
  if (emitter)
    emitter->finalize(GV);
 
  // If it is safe to mark the global 'constant', do so now.
  GV->setConstant(!NeedsGlobalCtor && !NeedsGlobalDtor &&
                  D->getType().isConstantStorage(getContext(), true, true));
 
  // If it is in a read-only section, mark it 'constant'.
  if (const SectionAttr *SA = D->getAttr<SectionAttr>()) {
    const ASTContext::SectionInfo &SI = Context.SectionInfos[SA->getName()];
    if ((SI.SectionFlags & ASTContext::PSF_Write) == 0)
      GV->setConstant(true);
  }
 
  CharUnits AlignVal = getContext().getDeclAlign(D);
  // Check for alignment specifed in an 'omp allocate' directive.
  if (std::optional<CharUnits> AlignValFromAllocate =
          getOMPAllocateAlignment(D))
    AlignVal = *AlignValFromAllocate;
  GV->setAlignment(AlignVal.getAsAlign());
 
  // On Darwin, unlike other Itanium C++ ABI platforms, the thread-wrapper
  // function is only defined alongside the variable, not also alongside
  // callers. Normally, all accesses to a thread_local go through the
  // thread-wrapper in order to ensure initialization has occurred, underlying
  // variable will never be used other than the thread-wrapper, so it can be
  // converted to internal linkage.
  //
  // However, if the variable has the 'constinit' attribute, it _can_ be
  // referenced directly, without calling the thread-wrapper, so the linkage
  // must not be changed.
  //
  // Additionally, if the variable isn't plain external linkage, e.g. if it's
  // weak or linkonce, the de-duplication semantics are important to preserve,
  // so we don't change the linkage.
  if (D->getTLSKind() == VarDecl::TLS_Dynamic &&
      Linkage == llvm::GlobalValue::ExternalLinkage &&
      Context.getTargetInfo().getTriple().isOSDarwin() &&
      !D->hasAttr<ConstInitAttr>())
    Linkage = llvm::GlobalValue::InternalLinkage;
 
  GV->setLinkage(Linkage);
  if (D->hasAttr<DLLImportAttr>())
    GV->setDLLStorageClass(llvm::GlobalVariable::DLLImportStorageClass);
  else if (D->hasAttr<DLLExportAttr>())
    GV->setDLLStorageClass(llvm::GlobalVariable::DLLExportStorageClass);
  else
    GV->setDLLStorageClass(llvm::GlobalVariable::DefaultStorageClass);
 
  if (Linkage == llvm::GlobalVariable::CommonLinkage) {
    // common vars aren't constant even if declared const.
    GV->setConstant(false);