Import LLVM 10.0.0 release including clang, lld and lldb.

ok hackroom
tested by plenty

1 files changed, 1206 insertions, 0 deletions

diff --git a/gnu/llvm/clang/lib/CodeGen/CodeGenAction.cpp b/gnu/llvm/clang/lib/CodeGen/CodeGenAction.cpp
new file mode 100644
index 00000000000..20ebaf3578d
--- /dev/null
+++ b/gnu/llvm/clang/lib/CodeGen/CodeGenAction.cpp
@@ -0,0 +1,1206 @@
+//===--- CodeGenAction.cpp - LLVM Code Generation Frontend Action ---------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/CodeGen/CodeGenAction.h"
+#include "CodeGenModule.h"
+#include "CoverageMappingGen.h"
+#include "MacroPPCallbacks.h"
+#include "clang/AST/ASTConsumer.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/DeclGroup.h"
+#include "clang/Basic/DiagnosticFrontend.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/Basic/LangStandard.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Basic/TargetInfo.h"
+#include "clang/CodeGen/BackendUtil.h"
+#include "clang/CodeGen/ModuleBuilder.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/FrontendDiagnostic.h"
+#include "clang/Lex/Preprocessor.h"
+#include "llvm/Bitcode/BitcodeReader.h"
+#include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
+#include "llvm/IR/DebugInfo.h"
+#include "llvm/IR/DiagnosticInfo.h"
+#include "llvm/IR/DiagnosticPrinter.h"
+#include "llvm/IR/GlobalValue.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/RemarkStreamer.h"
+#include "llvm/IRReader/IRReader.h"
+#include "llvm/Linker/Linker.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/TimeProfiler.h"
+#include "llvm/Support/Timer.h"
+#include "llvm/Support/ToolOutputFile.h"
+#include "llvm/Support/YAMLTraits.h"
+#include "llvm/Transforms/IPO/Internalize.h"
+
+#include <memory>
+using namespace clang;
+using namespace llvm;
+
+namespace clang {
+  class BackendConsumer;
+  class ClangDiagnosticHandler final : public DiagnosticHandler {
+  public:
+    ClangDiagnosticHandler(const CodeGenOptions &CGOpts, BackendConsumer *BCon)
+        : CodeGenOpts(CGOpts), BackendCon(BCon) {}
+
+    bool handleDiagnostics(const DiagnosticInfo &DI) override;
+
+    bool isAnalysisRemarkEnabled(StringRef PassName) const override {
+      return (CodeGenOpts.OptimizationRemarkAnalysisPattern &&
+              CodeGenOpts.OptimizationRemarkAnalysisPattern->match(PassName));
+    }
+    bool isMissedOptRemarkEnabled(StringRef PassName) const override {
+      return (CodeGenOpts.OptimizationRemarkMissedPattern &&
+              CodeGenOpts.OptimizationRemarkMissedPattern->match(PassName));
+    }
+    bool isPassedOptRemarkEnabled(StringRef PassName) const override {
+      return (CodeGenOpts.OptimizationRemarkPattern &&
+              CodeGenOpts.OptimizationRemarkPattern->match(PassName));
+    }
+
+    bool isAnyRemarkEnabled() const override {
+      return (CodeGenOpts.OptimizationRemarkAnalysisPattern ||
+              CodeGenOpts.OptimizationRemarkMissedPattern ||
+              CodeGenOpts.OptimizationRemarkPattern);
+    }
+
+  private:
+    const CodeGenOptions &CodeGenOpts;
+    BackendConsumer *BackendCon;
+  };
+
+  static void reportOptRecordError(Error E, DiagnosticsEngine &Diags,
+                                   const CodeGenOptions CodeGenOpts) {
+    handleAllErrors(
+        std::move(E),
+      [&](const RemarkSetupFileError &E) {
+          Diags.Report(diag::err_cannot_open_file)
+              << CodeGenOpts.OptRecordFile << E.message();
+        },
+      [&](const RemarkSetupPatternError &E) {
+          Diags.Report(diag::err_drv_optimization_remark_pattern)
+              << E.message() << CodeGenOpts.OptRecordPasses;
+        },
+      [&](const RemarkSetupFormatError &E) {
+          Diags.Report(diag::err_drv_optimization_remark_format)
+              << CodeGenOpts.OptRecordFormat;
+        });
+    }
+
+  class BackendConsumer : public ASTConsumer {
+    using LinkModule = CodeGenAction::LinkModule;
+
+    virtual void anchor();
+    DiagnosticsEngine &Diags;
+    BackendAction Action;
+    const HeaderSearchOptions &HeaderSearchOpts;
+    const CodeGenOptions &CodeGenOpts;
+    const TargetOptions &TargetOpts;
+    const LangOptions &LangOpts;
+    std::unique_ptr<raw_pwrite_stream> AsmOutStream;
+    ASTContext *Context;
+
+    Timer LLVMIRGeneration;
+    unsigned LLVMIRGenerationRefCount;
+
+    /// True if we've finished generating IR. This prevents us from generating
+    /// additional LLVM IR after emitting output in HandleTranslationUnit. This
+    /// can happen when Clang plugins trigger additional AST deserialization.
+    bool IRGenFinished = false;
+
+    std::unique_ptr<CodeGenerator> Gen;
+
+    SmallVector<LinkModule, 4> LinkModules;
+
+    // This is here so that the diagnostic printer knows the module a diagnostic
+    // refers to.
+    llvm::Module *CurLinkModule = nullptr;
+
+  public:
+    BackendConsumer(BackendAction Action, DiagnosticsEngine &Diags,
+                    const HeaderSearchOptions &HeaderSearchOpts,
+                    const PreprocessorOptions &PPOpts,
+                    const CodeGenOptions &CodeGenOpts,
+                    const TargetOptions &TargetOpts,
+                    const LangOptions &LangOpts, bool TimePasses,
+                    const std::string &InFile,
+                    SmallVector<LinkModule, 4> LinkModules,
+                    std::unique_ptr<raw_pwrite_stream> OS, LLVMContext &C,
+                    CoverageSourceInfo *CoverageInfo = nullptr)
+        : Diags(Diags), Action(Action), HeaderSearchOpts(HeaderSearchOpts),
+          CodeGenOpts(CodeGenOpts), TargetOpts(TargetOpts), LangOpts(LangOpts),
+          AsmOutStream(std::move(OS)), Context(nullptr),
+          LLVMIRGeneration("irgen", "LLVM IR Generation Time"),
+          LLVMIRGenerationRefCount(0),
+          Gen(CreateLLVMCodeGen(Diags, InFile, HeaderSearchOpts, PPOpts,
+                                CodeGenOpts, C, CoverageInfo)),
+          LinkModules(std::move(LinkModules)) {
+      FrontendTimesIsEnabled = TimePasses;
+      llvm::TimePassesIsEnabled = TimePasses;
+    }
+
+    // This constructor is used in installing an empty BackendConsumer
+    // to use the clang diagnostic handler for IR input files. It avoids
+    // initializing the OS field.
+    BackendConsumer(BackendAction Action, DiagnosticsEngine &Diags,
+                    const HeaderSearchOptions &HeaderSearchOpts,
+                    const PreprocessorOptions &PPOpts,
+                    const CodeGenOptions &CodeGenOpts,
+                    const TargetOptions &TargetOpts,
+                    const LangOptions &LangOpts, bool TimePasses,
+                    SmallVector<LinkModule, 4> LinkModules, LLVMContext &C,
+                    CoverageSourceInfo *CoverageInfo = nullptr)
+        : Diags(Diags), Action(Action), HeaderSearchOpts(HeaderSearchOpts),
+          CodeGenOpts(CodeGenOpts), TargetOpts(TargetOpts), LangOpts(LangOpts),
+          Context(nullptr),
+          LLVMIRGeneration("irgen", "LLVM IR Generation Time"),
+          LLVMIRGenerationRefCount(0),
+          Gen(CreateLLVMCodeGen(Diags, "", HeaderSearchOpts, PPOpts,
+                                CodeGenOpts, C, CoverageInfo)),
+          LinkModules(std::move(LinkModules)) {
+      FrontendTimesIsEnabled = TimePasses;
+      llvm::TimePassesIsEnabled = TimePasses;
+    }
+    llvm::Module *getModule() const { return Gen->GetModule(); }
+    std::unique_ptr<llvm::Module> takeModule() {
+      return std::unique_ptr<llvm::Module>(Gen->ReleaseModule());
+    }
+
+    CodeGenerator *getCodeGenerator() { return Gen.get(); }
+
+    void HandleCXXStaticMemberVarInstantiation(VarDecl *VD) override {
+      Gen->HandleCXXStaticMemberVarInstantiation(VD);
+    }
+
+    void Initialize(ASTContext &Ctx) override {
+      assert(!Context && "initialized multiple times");
+
+      Context = &Ctx;
+
+      if (FrontendTimesIsEnabled)
+        LLVMIRGeneration.startTimer();
+
+      Gen->Initialize(Ctx);
+
+      if (FrontendTimesIsEnabled)
+        LLVMIRGeneration.stopTimer();
+    }
+
+    bool HandleTopLevelDecl(DeclGroupRef D) override {
+      PrettyStackTraceDecl CrashInfo(*D.begin(), SourceLocation(),
+                                     Context->getSourceManager(),
+                                     "LLVM IR generation of declaration");
+
+      // Recurse.
+      if (FrontendTimesIsEnabled) {
+        LLVMIRGenerationRefCount += 1;
+        if (LLVMIRGenerationRefCount == 1)
+          LLVMIRGeneration.startTimer();
+      }
+
+      Gen->HandleTopLevelDecl(D);
+
+      if (FrontendTimesIsEnabled) {
+        LLVMIRGenerationRefCount -= 1;
+        if (LLVMIRGenerationRefCount == 0)
+          LLVMIRGeneration.stopTimer();
+      }
+
+      return true;
+    }
+
+    void HandleInlineFunctionDefinition(FunctionDecl *D) override {
+      PrettyStackTraceDecl CrashInfo(D, SourceLocation(),
+                                     Context->getSourceManager(),
+                                     "LLVM IR generation of inline function");
+      if (FrontendTimesIsEnabled)
+        LLVMIRGeneration.startTimer();
+
+      Gen->HandleInlineFunctionDefinition(D);
+
+      if (FrontendTimesIsEnabled)
+        LLVMIRGeneration.stopTimer();
+    }
+
+    void HandleInterestingDecl(DeclGroupRef D) override {
+      // Ignore interesting decls from the AST reader after IRGen is finished.
+      if (!IRGenFinished)
+        HandleTopLevelDecl(D);
+    }
+
+    // Links each entry in LinkModules into our module.  Returns true on error.
+    bool LinkInModules() {
+      for (auto &LM : LinkModules) {
+        if (LM.PropagateAttrs)
+          for (Function &F : *LM.Module)
+            Gen->CGM().AddDefaultFnAttrs(F);
+
+        CurLinkModule = LM.Module.get();
+
+        bool Err;
+        if (LM.Internalize) {
+          Err = Linker::linkModules(
+              *getModule(), std::move(LM.Module), LM.LinkFlags,
+              [](llvm::Module &M, const llvm::StringSet<> &GVS) {
+                internalizeModule(M, [&GVS](const llvm::GlobalValue &GV) {
+                  return !GV.hasName() || (GVS.count(GV.getName()) == 0);
+                });
+              });
+        } else {
+          Err = Linker::linkModules(*getModule(), std::move(LM.Module),
+                                    LM.LinkFlags);
+        }
+
+        if (Err)
+          return true;
+      }
+      return false; // success
+    }
+
+    void HandleTranslationUnit(ASTContext &C) override {
+      {
+        llvm::TimeTraceScope TimeScope("Frontend");
+        PrettyStackTraceString CrashInfo("Per-file LLVM IR generation");
+        if (FrontendTimesIsEnabled) {
+          LLVMIRGenerationRefCount += 1;
+          if (LLVMIRGenerationRefCount == 1)
+            LLVMIRGeneration.startTimer();
+        }
+
+        Gen->HandleTranslationUnit(C);
+
+        if (FrontendTimesIsEnabled) {
+          LLVMIRGenerationRefCount -= 1;
+          if (LLVMIRGenerationRefCount == 0)
+            LLVMIRGeneration.stopTimer();
+        }
+
+        IRGenFinished = true;
+      }
+
+      // Silently ignore if we weren't initialized for some reason.
+      if (!getModule())
+        return;
+
+      // Install an inline asm handler so that diagnostics get printed through
+      // our diagnostics hooks.
+      LLVMContext &Ctx = getModule()->getContext();
+      LLVMContext::InlineAsmDiagHandlerTy OldHandler =
+        Ctx.getInlineAsmDiagnosticHandler();
+      void *OldContext = Ctx.getInlineAsmDiagnosticContext();
+      Ctx.setInlineAsmDiagnosticHandler(InlineAsmDiagHandler, this);
+
+      std::unique_ptr<DiagnosticHandler> OldDiagnosticHandler =
+          Ctx.getDiagnosticHandler();
+      Ctx.setDiagnosticHandler(std::make_unique<ClangDiagnosticHandler>(
+        CodeGenOpts, this));
+
+      Expected<std::unique_ptr<llvm::ToolOutputFile>> OptRecordFileOrErr =
+          setupOptimizationRemarks(
+              Ctx, CodeGenOpts.OptRecordFile, CodeGenOpts.OptRecordPasses,
+              CodeGenOpts.OptRecordFormat, CodeGenOpts.DiagnosticsWithHotness,
+              CodeGenOpts.DiagnosticsHotnessThreshold);
+
+      if (Error E = OptRecordFileOrErr.takeError()) {
+        reportOptRecordError(std::move(E), Diags, CodeGenOpts);
+        return;
+      }
+
+      std::unique_ptr<llvm::ToolOutputFile> OptRecordFile =
+          std::move(*OptRecordFileOrErr);
+
+      if (OptRecordFile &&
+          CodeGenOpts.getProfileUse() != CodeGenOptions::ProfileNone)
+        Ctx.setDiagnosticsHotnessRequested(true);
+
+      // Link each LinkModule into our module.
+      if (LinkInModules())
+        return;
+
+      EmbedBitcode(getModule(), CodeGenOpts, llvm::MemoryBufferRef());
+
+      EmitBackendOutput(Diags, HeaderSearchOpts, CodeGenOpts, TargetOpts,
+                        LangOpts, C.getTargetInfo().getDataLayout(),
+                        getModule(), Action, std::move(AsmOutStream));
+
+      Ctx.setInlineAsmDiagnosticHandler(OldHandler, OldContext);
+
+      Ctx.setDiagnosticHandler(std::move(OldDiagnosticHandler));
+
+      if (OptRecordFile)
+        OptRecordFile->keep();
+    }
+
+    void HandleTagDeclDefinition(TagDecl *D) override {
+      PrettyStackTraceDecl CrashInfo(D, SourceLocation(),
+                                     Context->getSourceManager(),
+                                     "LLVM IR generation of declaration");
+      Gen->HandleTagDeclDefinition(D);
+    }
+
+    void HandleTagDeclRequiredDefinition(const TagDecl *D) override {
+      Gen->HandleTagDeclRequiredDefinition(D);
+    }
+
+    void CompleteTentativeDefinition(VarDecl *D) override {
+      Gen->CompleteTentativeDefinition(D);
+    }
+
+    void CompleteExternalDeclaration(VarDecl *D) override {
+      Gen->CompleteExternalDeclaration(D);
+    }
+
+    void AssignInheritanceModel(CXXRecordDecl *RD) override {
+      Gen->AssignInheritanceModel(RD);
+    }
+
+    void HandleVTable(CXXRecordDecl *RD) override {
+      Gen->HandleVTable(RD);
+    }
+
+    static void InlineAsmDiagHandler(const llvm::SMDiagnostic &SM,void *Context,
+                                     unsigned LocCookie) {
+      SourceLocation Loc = SourceLocation::getFromRawEncoding(LocCookie);
+      ((BackendConsumer*)Context)->InlineAsmDiagHandler2(SM, Loc);
+    }
+
+    /// Get the best possible source location to represent a diagnostic that
+    /// may have associated debug info.
+    const FullSourceLoc
+    getBestLocationFromDebugLoc(const llvm::DiagnosticInfoWithLocationBase &D,
+                                bool &BadDebugInfo, StringRef &Filename,
+                                unsigned &Line, unsigned &Column) const;
+
+    void InlineAsmDiagHandler2(const llvm::SMDiagnostic &,
+                               SourceLocation LocCookie);
+
+    void DiagnosticHandlerImpl(const llvm::DiagnosticInfo &DI);
+    /// Specialized handler for InlineAsm diagnostic.
+    /// \return True if the diagnostic has been successfully reported, false
+    /// otherwise.
+    bool InlineAsmDiagHandler(const llvm::DiagnosticInfoInlineAsm &D);
+    /// Specialized handler for StackSize diagnostic.
+    /// \return True if the diagnostic has been successfully reported, false
+    /// otherwise.
+    bool StackSizeDiagHandler(const llvm::DiagnosticInfoStackSize &D);
+    /// Specialized handler for unsupported backend feature diagnostic.
+    void UnsupportedDiagHandler(const llvm::DiagnosticInfoUnsupported &D);
+    /// Specialized handler for misexpect warnings.
+    /// Note that misexpect remarks are emitted through ORE
+    void MisExpectDiagHandler(const llvm::DiagnosticInfoMisExpect &D);
+    /// Specialized handlers for optimization remarks.
+    /// Note that these handlers only accept remarks and they always handle
+    /// them.
+    void EmitOptimizationMessage(const llvm::DiagnosticInfoOptimizationBase &D,
+                                 unsigned DiagID);
+    void
+    OptimizationRemarkHandler(const llvm::DiagnosticInfoOptimizationBase &D);
+    void OptimizationRemarkHandler(
+        const llvm::OptimizationRemarkAnalysisFPCommute &D);
+    void OptimizationRemarkHandler(
+        const llvm::OptimizationRemarkAnalysisAliasing &D);
+    void OptimizationFailureHandler(
+        const llvm::DiagnosticInfoOptimizationFailure &D);
+  };
+
+  void BackendConsumer::anchor() {}
+}
+
+bool ClangDiagnosticHandler::handleDiagnostics(const DiagnosticInfo &DI) {
+  BackendCon->DiagnosticHandlerImpl(DI);
+  return true;
+}
+
+/// ConvertBackendLocation - Convert a location in a temporary llvm::SourceMgr
+/// buffer to be a valid FullSourceLoc.
+static FullSourceLoc ConvertBackendLocation(const llvm::SMDiagnostic &D,
+                                            SourceManager &CSM) {
+  // Get both the clang and llvm source managers.  The location is relative to
+  // a memory buffer that the LLVM Source Manager is handling, we need to add
+  // a copy to the Clang source manager.
+  const llvm::SourceMgr &LSM = *D.getSourceMgr();
+
+  // We need to copy the underlying LLVM memory buffer because llvm::SourceMgr
+  // already owns its one and clang::SourceManager wants to own its one.
+  const MemoryBuffer *LBuf =
+  LSM.getMemoryBuffer(LSM.FindBufferContainingLoc(D.getLoc()));
+
+  // Create the copy and transfer ownership to clang::SourceManager.
+  // TODO: Avoid copying files into memory.
+  std::unique_ptr<llvm::MemoryBuffer> CBuf =
+      llvm::MemoryBuffer::getMemBufferCopy(LBuf->getBuffer(),
+                                           LBuf->getBufferIdentifier());
+  // FIXME: Keep a file ID map instead of creating new IDs for each location.
+  FileID FID = CSM.createFileID(std::move(CBuf));
+
+  // Translate the offset into the file.
+  unsigned Offset = D.getLoc().getPointer() - LBuf->getBufferStart();
+  SourceLocation NewLoc =
+  CSM.getLocForStartOfFile(FID).getLocWithOffset(Offset);
+  return FullSourceLoc(NewLoc, CSM);
+}
+
+
+/// InlineAsmDiagHandler2 - This function is invoked when the backend hits an
+/// error parsing inline asm.  The SMDiagnostic indicates the error relative to
+/// the temporary memory buffer that the inline asm parser has set up.
+void BackendConsumer::InlineAsmDiagHandler2(const llvm::SMDiagnostic &D,
+                                            SourceLocation LocCookie) {
+  // There are a couple of different kinds of errors we could get here.  First,
+  // we re-format the SMDiagnostic in terms of a clang diagnostic.
+
+  // Strip "error: " off the start of the message string.
+  StringRef Message = D.getMessage();
+  if (Message.startswith("error: "))
+    Message = Message.substr(7);
+
+  // If the SMDiagnostic has an inline asm source location, translate it.
+  FullSourceLoc Loc;
+  if (D.getLoc() != SMLoc())
+    Loc = ConvertBackendLocation(D, Context->getSourceManager());
+
+  unsigned DiagID;
+  switch (D.getKind()) {
+  case llvm::SourceMgr::DK_Error:
+    DiagID = diag::err_fe_inline_asm;
+    break;
+  case llvm::SourceMgr::DK_Warning:
+    DiagID = diag::warn_fe_inline_asm;
+    break;
+  case llvm::SourceMgr::DK_Note:
+    DiagID = diag::note_fe_inline_asm;
+    break;
+  case llvm::SourceMgr::DK_Remark:
+    llvm_unreachable("remarks unexpected");
+  }
+  // If this problem has clang-level source location information, report the
+  // issue in the source with a note showing the instantiated
+  // code.
+  if (LocCookie.isValid()) {
+    Diags.Report(LocCookie, DiagID).AddString(Message);
+
+    if (D.getLoc().isValid()) {
+      DiagnosticBuilder B = Diags.Report(Loc, diag::note_fe_inline_asm_here);
+      // Convert the SMDiagnostic ranges into SourceRange and attach them
+      // to the diagnostic.
+      for (const std::pair<unsigned, unsigned> &Range : D.getRanges()) {
+        unsigned Column = D.getColumnNo();
+        B << SourceRange(Loc.getLocWithOffset(Range.first - Column),
+                         Loc.getLocWithOffset(Range.second - Column));
+      }
+    }
+    return;
+  }
+
+  // Otherwise, report the backend issue as occurring in the generated .s file.
+  // If Loc is invalid, we still need to report the issue, it just gets no
+  // location info.
+  Diags.Report(Loc, DiagID).AddString(Message);
+}
+
+#define ComputeDiagID(Severity, GroupName, DiagID)                             \
+  do {                                                                         \
+    switch (Severity) {                                                        \
+    case llvm::DS_Error:                                                       \
+      DiagID = diag::err_fe_##GroupName;                                       \
+      break;                                                                   \
+    case llvm::DS_Warning:                                                     \
+      DiagID = diag::warn_fe_##GroupName;                                      \
+      break;                                                                   \
+    case llvm::DS_Remark:                                                      \
+      llvm_unreachable("'remark' severity not expected");                      \
+      break;                                                                   \
+    case llvm::DS_Note:                                                        \
+      DiagID = diag::note_fe_##GroupName;                                      \
+      break;                                                                   \
+    }                                                                          \
+  } while (false)
+
+#define ComputeDiagRemarkID(Severity, GroupName, DiagID)                       \
+  do {                                                                         \
+    switch (Severity) {                                                        \
+    case llvm::DS_Error:                                                       \
+      DiagID = diag::err_fe_##GroupName;                                       \
+      break;                                                                   \
+    case llvm::DS_Warning:                                                     \
+      DiagID = diag::warn_fe_##GroupName;                                      \
+      break;                                                                   \
+    case llvm::DS_Remark:                                                      \
+      DiagID = diag::remark_fe_##GroupName;                                    \
+      break;                                                                   \
+    case llvm::DS_Note:                                                        \
+      DiagID = diag::note_fe_##GroupName;                                      \
+      break;                                                                   \
+    }                                                                          \
+  } while (false)
+
+bool
+BackendConsumer::InlineAsmDiagHandler(const llvm::DiagnosticInfoInlineAsm &D) {
+  unsigned DiagID;
+  ComputeDiagID(D.getSeverity(), inline_asm, DiagID);
+  std::string Message = D.getMsgStr().str();
+
+  // If this problem has clang-level source location information, report the
+  // issue as being a problem in the source with a note showing the instantiated
+  // code.
+  SourceLocation LocCookie =
+      SourceLocation::getFromRawEncoding(D.getLocCookie());
+  if (LocCookie.isValid())
+    Diags.Report(LocCookie, DiagID).AddString(Message);
+  else {
+    // Otherwise, report the backend diagnostic as occurring in the generated
+    // .s file.
+    // If Loc is invalid, we still need to report the diagnostic, it just gets
+    // no location info.
+    FullSourceLoc Loc;
+    Diags.Report(Loc, DiagID).AddString(Message);
+  }
+  // We handled all the possible severities.
+  return true;
+}
+
+bool
+BackendConsumer::StackSizeDiagHandler(const llvm::DiagnosticInfoStackSize &D) {
+  if (D.getSeverity() != llvm::DS_Warning)
+    // For now, the only support we have for StackSize diagnostic is warning.
+    // We do not know how to format other severities.
+    return false;
+
+  if (const Decl *ND = Gen->GetDeclForMangledName(D.getFunction().getName())) {
+    // FIXME: Shouldn't need to truncate to uint32_t
+    Diags.Report(ND->getASTContext().getFullLoc(ND->getLocation()),
+                 diag::warn_fe_frame_larger_than)
+      << static_cast<uint32_t>(D.getStackSize()) << Decl::castToDeclContext(ND);
+    return true;
+  }
+
+  return false;
+}
+
+const FullSourceLoc BackendConsumer::getBestLocationFromDebugLoc(
+    const llvm::DiagnosticInfoWithLocationBase &D, bool &BadDebugInfo,
+    StringRef &Filename, unsigned &Line, unsigned &Column) const {
+  SourceManager &SourceMgr = Context->getSourceManager();
+  FileManager &FileMgr = SourceMgr.getFileManager();
+  SourceLocation DILoc;
+
+  if (D.isLocationAvailable()) {
+    D.getLocation(Filename, Line, Column);
+    if (Line > 0) {
+      auto FE = FileMgr.getFile(Filename);
+      if (!FE)
+        FE = FileMgr.getFile(D.getAbsolutePath());
+      if (FE) {
+        // If -gcolumn-info was not used, Column will be 0. This upsets the
+        // source manager, so pass 1 if Column is not set.
+        DILoc = SourceMgr.translateFileLineCol(*FE, Line, Column ? Column : 1);
+      }
+    }
+    BadDebugInfo = DILoc.isInvalid();
+  }
+
+  // If a location isn't available, try to approximate it using the associated
+  // function definition. We use the definition's right brace to differentiate
+  // from diagnostics that genuinely relate to the function itself.
+  FullSourceLoc Loc(DILoc, SourceMgr);
+  if (Loc.isInvalid())
+    if (const Decl *FD = Gen->GetDeclForMangledName(D.getFunction().getName()))
+      Loc = FD->getASTContext().getFullLoc(FD->getLocation());
+
+  if (DILoc.isInvalid() && D.isLocationAvailable())
+    // If we were not able to translate the file:line:col information
+    // back to a SourceLocation, at least emit a note stating that
+    // we could not translate this location. This can happen in the
+    // case of #line directives.
+    Diags.Report(Loc, diag::note_fe_backend_invalid_loc)
+        << Filename << Line << Column;
+
+  return Loc;
+}
+
+void BackendConsumer::UnsupportedDiagHandler(
+    const llvm::DiagnosticInfoUnsupported &D) {
+  // We only support errors.
+  assert(D.getSeverity() == llvm::DS_Error);
+
+  StringRef Filename;
+  unsigned Line, Column;
+  bool BadDebugInfo = false;
+  FullSourceLoc Loc;
+  std::string Msg;
+  raw_string_ostream MsgStream(Msg);
+
+  // Context will be nullptr for IR input files, we will construct the diag
+  // message from llvm::DiagnosticInfoUnsupported.
+  if (Context != nullptr) {
+    Loc = getBestLocationFromDebugLoc(D, BadDebugInfo, Filename, Line, Column);
+    MsgStream << D.getMessage();
+  } else {
+    DiagnosticPrinterRawOStream DP(MsgStream);
+    D.print(DP);
+  }
+  Diags.Report(Loc, diag::err_fe_backend_unsupported) << MsgStream.str();
+
+  if (BadDebugInfo)
+    // If we were not able to translate the file:line:col information
+    // back to a SourceLocation, at least emit a note stating that
+    // we could not translate this location. This can happen in the
+    // case of #line directives.
+    Diags.Report(Loc, diag::note_fe_backend_invalid_loc)
+        << Filename << Line << Column;
+}
+
+void BackendConsumer::MisExpectDiagHandler(
+    const llvm::DiagnosticInfoMisExpect &D) {
+  StringRef Filename;
+  unsigned Line, Column;
+  bool BadDebugInfo = false;
+  FullSourceLoc Loc;
+  std::string Msg;
+  raw_string_ostream MsgStream(Msg);
+  DiagnosticPrinterRawOStream DP(MsgStream);
+
+  // Context will be nullptr for IR input files, we will construct the diag
+  // message from llvm::DiagnosticInfoMisExpect.
+  if (Context != nullptr) {
+    Loc = getBestLocationFromDebugLoc(D, BadDebugInfo, Filename, Line, Column);
+    MsgStream << D.getMsg();
+  } else {
+    DiagnosticPrinterRawOStream DP(MsgStream);
+    D.print(DP);
+  }
+  Diags.Report(Loc, diag::warn_profile_data_misexpect) << MsgStream.str();
+
+  if (BadDebugInfo)
+    // If we were not able to translate the file:line:col information
+    // back to a SourceLocation, at least emit a note stating that
+    // we could not translate this location. This can happen in the
+    // case of #line directives.
+    Diags.Report(Loc, diag::note_fe_backend_invalid_loc)
+        << Filename << Line << Column;
+}
+
+void BackendConsumer::EmitOptimizationMessage(
+    const llvm::DiagnosticInfoOptimizationBase &D, unsigned DiagID) {
+  // We only support warnings and remarks.
+  assert(D.getSeverity() == llvm::DS_Remark ||
+         D.getSeverity() == llvm::DS_Warning);
+
+  StringRef Filename;
+  unsigned Line, Column;
+  bool BadDebugInfo = false;
+  FullSourceLoc Loc;
+  std::string Msg;
+  raw_string_ostream MsgStream(Msg);
+
+  // Context will be nullptr for IR input files, we will construct the remark
+  // message from llvm::DiagnosticInfoOptimizationBase.
+  if (Context != nullptr) {
+    Loc = getBestLocationFromDebugLoc(D, BadDebugInfo, Filename, Line, Column);
+    MsgStream << D.getMsg();
+  } else {
+    DiagnosticPrinterRawOStream DP(MsgStream);
+    D.print(DP);
+  }
+
+  if (D.getHotness())
+    MsgStream << " (hotness: " << *D.getHotness() << ")";
+
+  Diags.Report(Loc, DiagID)
+      << AddFlagValue(D.getPassName())
+      << MsgStream.str();
+
+  if (BadDebugInfo)
+    // If we were not able to translate the file:line:col information
+    // back to a SourceLocation, at least emit a note stating that
+    // we could not translate this location. This can happen in the
+    // case of #line directives.
+    Diags.Report(Loc, diag::note_fe_backend_invalid_loc)
+        << Filename << Line << Column;
+}
+
+void BackendConsumer::OptimizationRemarkHandler(
+    const llvm::DiagnosticInfoOptimizationBase &D) {
+  // Without hotness information, don't show noisy remarks.
+  if (D.isVerbose() && !D.getHotness())
+    return;
+
+  if (D.isPassed()) {
+    // Optimization remarks are active only if the -Rpass flag has a regular
+    // expression that matches the name of the pass name in \p D.
+    if (CodeGenOpts.OptimizationRemarkPattern &&
+        CodeGenOpts.OptimizationRemarkPattern->match(D.getPassName()))
+      EmitOptimizationMessage(D, diag::remark_fe_backend_optimization_remark);
+  } else if (D.isMissed()) {
+    // Missed optimization remarks are active only if the -Rpass-missed
+    // flag has a regular expression that matches the name of the pass
+    // name in \p D.
+    if (CodeGenOpts.OptimizationRemarkMissedPattern &&
+        CodeGenOpts.OptimizationRemarkMissedPattern->match(D.getPassName()))
+      EmitOptimizationMessage(
+          D, diag::remark_fe_backend_optimization_remark_missed);
+  } else {
+    assert(D.isAnalysis() && "Unknown remark type");
+
+    bool ShouldAlwaysPrint = false;
+    if (auto *ORA = dyn_cast<llvm::OptimizationRemarkAnalysis>(&D))
+      ShouldAlwaysPrint = ORA->shouldAlwaysPrint();
+
+    if (ShouldAlwaysPrint ||
+        (CodeGenOpts.OptimizationRemarkAnalysisPattern &&
+         CodeGenOpts.OptimizationRemarkAnalysisPattern->match(D.getPassName())))
+      EmitOptimizationMessage(
+          D, diag::remark_fe_backend_optimization_remark_analysis);
+  }
+}
+
+void BackendConsumer::OptimizationRemarkHandler(
+    const llvm::OptimizationRemarkAnalysisFPCommute &D) {
+  // Optimization analysis remarks are active if the pass name is set to
+  // llvm::DiagnosticInfo::AlwasyPrint or if the -Rpass-analysis flag has a
+  // regular expression that matches the name of the pass name in \p D.
+
+  if (D.shouldAlwaysPrint() ||
+      (CodeGenOpts.OptimizationRemarkAnalysisPattern &&
+       CodeGenOpts.OptimizationRemarkAnalysisPattern->match(D.getPassName())))
+    EmitOptimizationMessage(
+        D, diag::remark_fe_backend_optimization_remark_analysis_fpcommute);
+}
+
+void BackendConsumer::OptimizationRemarkHandler(
+    const llvm::OptimizationRemarkAnalysisAliasing &D) {
+  // Optimization analysis remarks are active if the pass name is set to
+  // llvm::DiagnosticInfo::AlwasyPrint or if the -Rpass-analysis flag has a
+  // regular expression that matches the name of the pass name in \p D.
+
+  if (D.shouldAlwaysPrint() ||
+      (CodeGenOpts.OptimizationRemarkAnalysisPattern &&
+       CodeGenOpts.OptimizationRemarkAnalysisPattern->match(D.getPassName())))
+    EmitOptimizationMessage(
+        D, diag::remark_fe_backend_optimization_remark_analysis_aliasing);
+}
+
+void BackendConsumer::OptimizationFailureHandler(
+    const llvm::DiagnosticInfoOptimizationFailure &D) {
+  EmitOptimizationMessage(D, diag::warn_fe_backend_optimization_failure);
+}
+
+/// This function is invoked when the backend needs
+/// to report something to the user.
+void BackendConsumer::DiagnosticHandlerImpl(const DiagnosticInfo &DI) {
+  unsigned DiagID = diag::err_fe_inline_asm;
+  llvm::DiagnosticSeverity Severity = DI.getSeverity();
+  // Get the diagnostic ID based.
+  switch (DI.getKind()) {
+  case llvm::DK_InlineAsm:
+    if (InlineAsmDiagHandler(cast<DiagnosticInfoInlineAsm>(DI)))
+      return;
+    ComputeDiagID(Severity, inline_asm, DiagID);
+    break;
+  case llvm::DK_StackSize:
+    if (StackSizeDiagHandler(cast<DiagnosticInfoStackSize>(DI)))
+      return;
+    ComputeDiagID(Severity, backend_frame_larger_than, DiagID);
+    break;
+  case DK_Linker:
+    assert(CurLinkModule);
+    // FIXME: stop eating the warnings and notes.
+    if (Severity != DS_Error)
+      return;
+    DiagID = diag::err_fe_cannot_link_module;
+    break;
+  case llvm::DK_OptimizationRemark:
+    // Optimization remarks are always handled completely by this
+    // handler. There is no generic way of emitting them.
+    OptimizationRemarkHandler(cast<OptimizationRemark>(DI));
+    return;
+  case llvm::DK_OptimizationRemarkMissed:
+    // Optimization remarks are always handled completely by this
+    // handler. There is no generic way of emitting them.
+    OptimizationRemarkHandler(cast<OptimizationRemarkMissed>(DI));
+    return;
+  case llvm::DK_OptimizationRemarkAnalysis:
+    // Optimization remarks are always handled completely by this
+    // handler. There is no generic way of emitting them.
+    OptimizationRemarkHandler(cast<OptimizationRemarkAnalysis>(DI));
+    return;
+  case llvm::DK_OptimizationRemarkAnalysisFPCommute:
+    // Optimization remarks are always handled completely by this
+    // handler. There is no generic way of emitting them.
+    OptimizationRemarkHandler(cast<OptimizationRemarkAnalysisFPCommute>(DI));
+    return;
+  case llvm::DK_OptimizationRemarkAnalysisAliasing:
+    // Optimization remarks are always handled completely by this
+    // handler. There is no generic way of emitting them.
+    OptimizationRemarkHandler(cast<OptimizationRemarkAnalysisAliasing>(DI));
+    return;
+  case llvm::DK_MachineOptimizationRemark:
+    // Optimization remarks are always handled completely by this
+    // handler. There is no generic way of emitting them.
+    OptimizationRemarkHandler(cast<MachineOptimizationRemark>(DI));
+    return;
+  case llvm::DK_MachineOptimizationRemarkMissed:
+    // Optimization remarks are always handled completely by this
+    // handler. There is no generic way of emitting them.
+    OptimizationRemarkHandler(cast<MachineOptimizationRemarkMissed>(DI));
+    return;
+  case llvm::DK_MachineOptimizationRemarkAnalysis:
+    // Optimization remarks are always handled completely by this
+    // handler. There is no generic way of emitting them.
+    OptimizationRemarkHandler(cast<MachineOptimizationRemarkAnalysis>(DI));
+    return;
+  case llvm::DK_OptimizationFailure:
+    // Optimization failures are always handled completely by this
+    // handler.
+    OptimizationFailureHandler(cast<DiagnosticInfoOptimizationFailure>(DI));
+    return;
+  case llvm::DK_Unsupported:
+    UnsupportedDiagHandler(cast<DiagnosticInfoUnsupported>(DI));
+    return;
+  case llvm::DK_MisExpect:
+    MisExpectDiagHandler(cast<DiagnosticInfoMisExpect>(DI));
+    return;
+  default:
+    // Plugin IDs are not bound to any value as they are set dynamically.
+    ComputeDiagRemarkID(Severity, backend_plugin, DiagID);
+    break;
+  }
+  std::string MsgStorage;
+  {
+    raw_string_ostream Stream(MsgStorage);
+    DiagnosticPrinterRawOStream DP(Stream);
+    DI.print(DP);
+  }
+
+  if (DiagID == diag::err_fe_cannot_link_module) {
+    Diags.Report(diag::err_fe_cannot_link_module)
+        << CurLinkModule->getModuleIdentifier() << MsgStorage;
+    return;
+  }
+
+  // Report the backend message using the usual diagnostic mechanism.
+  FullSourceLoc Loc;
+  Diags.Report(Loc, DiagID).AddString(MsgStorage);
+}
+#undef ComputeDiagID
+
+CodeGenAction::CodeGenAction(unsigned _Act, LLVMContext *_VMContext)
+    : Act(_Act), VMContext(_VMContext ? _VMContext : new LLVMContext),
+      OwnsVMContext(!_VMContext) {}
+
+CodeGenAction::~CodeGenAction() {
+  TheModule.reset();
+  if (OwnsVMContext)
+    delete VMContext;
+}
+
+bool CodeGenAction::hasIRSupport() const { return true; }
+
+void CodeGenAction::EndSourceFileAction() {
+  // If the consumer creation failed, do nothing.
+  if (!getCompilerInstance().hasASTConsumer())
+    return;
+
+  // Steal the module from the consumer.
+  TheModule = BEConsumer->takeModule();
+}
+
+std::unique_ptr<llvm::Module> CodeGenAction::takeModule() {
+  return std::move(TheModule);
+}
+
+llvm::LLVMContext *CodeGenAction::takeLLVMContext() {
+  OwnsVMContext = false;
+  return VMContext;
+}
+
+static std::unique_ptr<raw_pwrite_stream>
+GetOutputStream(CompilerInstance &CI, StringRef InFile, BackendAction Action) {
+  switch (Action) {
+  case Backend_EmitAssembly:
+    return CI.createDefaultOutputFile(false, InFile, "s");
+  case Backend_EmitLL:
+    return CI.createDefaultOutputFile(false, InFile, "ll");
+  case Backend_EmitBC:
+    return CI.createDefaultOutputFile(true, InFile, "bc");
+  case Backend_EmitNothing:
+    return nullptr;
+  case Backend_EmitMCNull:
+    return CI.createNullOutputFile();
+  case Backend_EmitObj:
+    return CI.createDefaultOutputFile(true, InFile, "o");
+  }
+
+  llvm_unreachable("Invalid action!");
+}
+
+std::unique_ptr<ASTConsumer>
+CodeGenAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
+  BackendAction BA = static_cast<BackendAction>(Act);
+  std::unique_ptr<raw_pwrite_stream> OS = CI.takeOutputStream();
+  if (!OS)
+    OS = GetOutputStream(CI, InFile, BA);
+
+  if (BA != Backend_EmitNothing && !OS)
+    return nullptr;
+
+  // Load bitcode modules to link with, if we need to.
+  if (LinkModules.empty())
+    for (const CodeGenOptions::BitcodeFileToLink &F :
+         CI.getCodeGenOpts().LinkBitcodeFiles) {
+      auto BCBuf = CI.getFileManager().getBufferForFile(F.Filename);
+      if (!BCBuf) {
+        CI.getDiagnostics().Report(diag::err_cannot_open_file)
+            << F.Filename << BCBuf.getError().message();
+        LinkModules.clear();
+        return nullptr;
+      }
+
+      Expected<std::unique_ptr<llvm::Module>> ModuleOrErr =
+          getOwningLazyBitcodeModule(std::move(*BCBuf), *VMContext);
+      if (!ModuleOrErr) {
+        handleAllErrors(ModuleOrErr.takeError(), [&](ErrorInfoBase &EIB) {
+          CI.getDiagnostics().Report(diag::err_cannot_open_file)
+              << F.Filename << EIB.message();
+        });
+        LinkModules.clear();
+        return nullptr;
+      }
+      LinkModules.push_back({std::move(ModuleOrErr.get()), F.PropagateAttrs,
+                             F.Internalize, F.LinkFlags});
+    }
+
+  CoverageSourceInfo *CoverageInfo = nullptr;
+  // Add the preprocessor callback only when the coverage mapping is generated.
+  if (CI.getCodeGenOpts().CoverageMapping) {
+    CoverageInfo = new CoverageSourceInfo;
+    CI.getPreprocessor().addPPCallbacks(
+                                    std::unique_ptr<PPCallbacks>(CoverageInfo));
+  }
+
+  std::unique_ptr<BackendConsumer> Result(new BackendConsumer(
+      BA, CI.getDiagnostics(), CI.getHeaderSearchOpts(),
+      CI.getPreprocessorOpts(), CI.getCodeGenOpts(), CI.getTargetOpts(),
+      CI.getLangOpts(), CI.getFrontendOpts().ShowTimers, InFile,
+      std::move(LinkModules), std::move(OS), *VMContext, CoverageInfo));
+  BEConsumer = Result.get();
+
+  // Enable generating macro debug info only when debug info is not disabled and
+  // also macro debug info is enabled.
+  if (CI.getCodeGenOpts().getDebugInfo() != codegenoptions::NoDebugInfo &&
+      CI.getCodeGenOpts().MacroDebugInfo) {
+    std::unique_ptr<PPCallbacks> Callbacks =
+        std::make_unique<MacroPPCallbacks>(BEConsumer->getCodeGenerator(),
+                                            CI.getPreprocessor());
+    CI.getPreprocessor().addPPCallbacks(std::move(Callbacks));
+  }
+
+  return std::move(Result);
+}
+
+static void BitcodeInlineAsmDiagHandler(const llvm::SMDiagnostic &SM,
+                                         void *Context,
+                                         unsigned LocCookie) {
+  SM.print(nullptr, llvm::errs());
+
+  auto Diags = static_cast<DiagnosticsEngine *>(Context);
+  unsigned DiagID;
+  switch (SM.getKind()) {
+  case llvm::SourceMgr::DK_Error:
+    DiagID = diag::err_fe_inline_asm;
+    break;
+  case llvm::SourceMgr::DK_Warning:
+    DiagID = diag::warn_fe_inline_asm;
+    break;
+  case llvm::SourceMgr::DK_Note:
+    DiagID = diag::note_fe_inline_asm;
+    break;
+  case llvm::SourceMgr::DK_Remark:
+    llvm_unreachable("remarks unexpected");
+  }
+
+  Diags->Report(DiagID).AddString("cannot compile inline asm");
+}
+
+std::unique_ptr<llvm::Module>
+CodeGenAction::loadModule(MemoryBufferRef MBRef) {
+  CompilerInstance &CI = getCompilerInstance();
+  SourceManager &SM = CI.getSourceManager();
+
+  // For ThinLTO backend invocations, ensure that the context
+  // merges types based on ODR identifiers. We also need to read
+  // the correct module out of a multi-module bitcode file.
+  if (!CI.getCodeGenOpts().ThinLTOIndexFile.empty()) {
+    VMContext->enableDebugTypeODRUniquing();
+
+    auto DiagErrors = [&](Error E) -> std::unique_ptr<llvm::Module> {
+      unsigned DiagID =
+          CI.getDiagnostics().getCustomDiagID(DiagnosticsEngine::Error, "%0");
+      handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
+        CI.getDiagnostics().Report(DiagID) << EIB.message();
+      });
+      return {};
+    };
+
+    Expected<std::vector<BitcodeModule>> BMsOrErr = getBitcodeModuleList(MBRef);
+    if (!BMsOrErr)
+      return DiagErrors(BMsOrErr.takeError());
+    BitcodeModule *Bm = FindThinLTOModule(*BMsOrErr);
+    // We have nothing to do if the file contains no ThinLTO module. This is
+    // possible if ThinLTO compilation was not able to split module. Content of
+    // the file was already processed by indexing and will be passed to the
+    // linker using merged object file.
+    if (!Bm) {
+      auto M = std::make_unique<llvm::Module>("empty", *VMContext);
+      M->setTargetTriple(CI.getTargetOpts().Triple);
+      return M;
+    }
+    Expected<std::unique_ptr<llvm::Module>> MOrErr =
+        Bm->parseModule(*VMContext);
+    if (!MOrErr)
+      return DiagErrors(MOrErr.takeError());
+    return std::move(*MOrErr);
+  }
+
+  llvm::SMDiagnostic Err;
+  if (std::unique_ptr<llvm::Module> M = parseIR(MBRef, Err, *VMContext))
+    return M;
+
+  // Translate from the diagnostic info to the SourceManager location if
+  // available.
+  // TODO: Unify this with ConvertBackendLocation()
+  SourceLocation Loc;
+  if (Err.getLineNo() > 0) {
+    assert(Err.getColumnNo() >= 0);
+    Loc = SM.translateFileLineCol(SM.getFileEntryForID(SM.getMainFileID()),
+                                  Err.getLineNo(), Err.getColumnNo() + 1);
+  }
+
+  // Strip off a leading diagnostic code if there is one.
+  StringRef Msg = Err.getMessage();
+  if (Msg.startswith("error: "))
+    Msg = Msg.substr(7);
+
+  unsigned DiagID =
+      CI.getDiagnostics().getCustomDiagID(DiagnosticsEngine::Error, "%0");
+
+  CI.getDiagnostics().Report(Loc, DiagID) << Msg;
+  return {};
+}
+
+void CodeGenAction::ExecuteAction() {
+  // If this is an IR file, we have to treat it specially.
+  if (getCurrentFileKind().getLanguage() == Language::LLVM_IR) {
+    BackendAction BA = static_cast<BackendAction>(Act);
+    CompilerInstance &CI = getCompilerInstance();
+    auto &CodeGenOpts = CI.getCodeGenOpts();
+    auto &Diagnostics = CI.getDiagnostics();
+    std::unique_ptr<raw_pwrite_stream> OS =
+        GetOutputStream(CI, getCurrentFile(), BA);
+    if (BA != Backend_EmitNothing && !OS)
+      return;
+
+    bool Invalid;
+    SourceManager &SM = CI.getSourceManager();
+    FileID FID = SM.getMainFileID();
+    const llvm::MemoryBuffer *MainFile = SM.getBuffer(FID, &Invalid);
+    if (Invalid)
+      return;
+
+    TheModule = loadModule(*MainFile);
+    if (!TheModule)
+      return;
+
+    const TargetOptions &TargetOpts = CI.getTargetOpts();
+    if (TheModule->getTargetTriple() != TargetOpts.Triple) {
+      Diagnostics.Report(SourceLocation(),
+                         diag::warn_fe_override_module)
+          << TargetOpts.Triple;
+      TheModule->setTargetTriple(TargetOpts.Triple);
+    }
+
+    EmbedBitcode(TheModule.get(), CodeGenOpts,
+                 MainFile->getMemBufferRef());
+
+    LLVMContext &Ctx = TheModule->getContext();
+    Ctx.setInlineAsmDiagnosticHandler(BitcodeInlineAsmDiagHandler,
+                                      &Diagnostics);
+
+    // Set clang diagnostic handler. To do this we need to create a fake
+    // BackendConsumer.
+    BackendConsumer Result(BA, CI.getDiagnostics(), CI.getHeaderSearchOpts(),
+                           CI.getPreprocessorOpts(), CI.getCodeGenOpts(),
+                           CI.getTargetOpts(), CI.getLangOpts(),
+                           CI.getFrontendOpts().ShowTimers,
+                           std::move(LinkModules), *VMContext, nullptr);
+    // PR44896: Force DiscardValueNames as false. DiscardValueNames cannot be
+    // true here because the valued names are needed for reading textual IR.
+    Ctx.setDiscardValueNames(false);
+    Ctx.setDiagnosticHandler(
+        std::make_unique<ClangDiagnosticHandler>(CodeGenOpts, &Result));
+
+    Expected<std::unique_ptr<llvm::ToolOutputFile>> OptRecordFileOrErr =
+        setupOptimizationRemarks(
+            Ctx, CodeGenOpts.OptRecordFile, CodeGenOpts.OptRecordPasses,
+            CodeGenOpts.OptRecordFormat, CodeGenOpts.DiagnosticsWithHotness,
+            CodeGenOpts.DiagnosticsHotnessThreshold);
+
+    if (Error E = OptRecordFileOrErr.takeError()) {
+      reportOptRecordError(std::move(E), Diagnostics, CodeGenOpts);
+      return;
+    }
+    std::unique_ptr<llvm::ToolOutputFile> OptRecordFile =
+        std::move(*OptRecordFileOrErr);
+
+    EmitBackendOutput(Diagnostics, CI.getHeaderSearchOpts(), CodeGenOpts,
+                      TargetOpts, CI.getLangOpts(),
+                      CI.getTarget().getDataLayout(), TheModule.get(), BA,
+                      std::move(OS));
+
+    if (OptRecordFile)
+      OptRecordFile->keep();
+    return;
+  }
+
+  // Otherwise follow the normal AST path.
+  this->ASTFrontendAction::ExecuteAction();
+}
+
+//
+
+void EmitAssemblyAction::anchor() { }
+EmitAssemblyAction::EmitAssemblyAction(llvm::LLVMContext *_VMContext)
+  : CodeGenAction(Backend_EmitAssembly, _VMContext) {}
+
+void EmitBCAction::anchor() { }
+EmitBCAction::EmitBCAction(llvm::LLVMContext *_VMContext)
+  : CodeGenAction(Backend_EmitBC, _VMContext) {}
+
+void EmitLLVMAction::anchor() { }
+EmitLLVMAction::EmitLLVMAction(llvm::LLVMContext *_VMContext)
+  : CodeGenAction(Backend_EmitLL, _VMContext) {}
+
+void EmitLLVMOnlyAction::anchor() { }
+EmitLLVMOnlyAction::EmitLLVMOnlyAction(llvm::LLVMContext *_VMContext)
+  : CodeGenAction(Backend_EmitNothing, _VMContext) {}
+
+void EmitCodeGenOnlyAction::anchor() { }
+EmitCodeGenOnlyAction::EmitCodeGenOnlyAction(llvm::LLVMContext *_VMContext)
+  : CodeGenAction(Backend_EmitMCNull, _VMContext) {}
+
+void EmitObjAction::anchor() { }
+EmitObjAction::EmitObjAction(llvm::LLVMContext *_VMContext)
+  : CodeGenAction(Backend_EmitObj, _VMContext) {}