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[CIR] Add framework for CIR to LLVM IR lowering
Create the skeleton framework for lowering from ClangIR to LLVM IR. This initial implementation just creates an empty LLVM IR module. Actual lowering of even minimal ClangIR is deferred to a later patch.
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11 files changed

+160
-15
lines changed

11 files changed

+160
-15
lines changed

‎clang/include/clang/CIR/CIRGenerator.h‎

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@@ -55,6 +55,9 @@ class CIRGenerator : public clang::ASTConsumer {
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void Initialize(clang::ASTContext &astContext) override;
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bool HandleTopLevelDecl(clang::DeclGroupRef group) override;
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mlir::ModuleOp getModule() const;
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std::unique_ptr<mlir::MLIRContext> takeContext() {
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return std::move(mlirContext);
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};
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};
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} // namespace cir

‎clang/include/clang/CIR/FrontendAction/CIRGenAction.h‎

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@@ -26,6 +26,7 @@ class CIRGenAction : public clang::ASTFrontendAction {
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public:
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enum class OutputType {
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EmitCIR,
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EmitLLVM,
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};
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private:
@@ -55,6 +56,13 @@ class EmitCIRAction : public CIRGenAction {
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EmitCIRAction(mlir::MLIRContext *MLIRCtx = nullptr);
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};
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class EmitLLVMAction : public CIRGenAction {
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virtual void anchor();
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public:
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EmitLLVMAction(mlir::MLIRContext *MLIRCtx = nullptr);
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};
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} // namespace cir
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#endif

‎clang/include/clang/CIR/LowerToLLVM.h‎

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@@ -0,0 +1,36 @@
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//====- LowerToLLVM.h- Lowering from CIR to LLVM --------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file declares an interface for converting CIR modules to LLVM IR.
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//
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//===----------------------------------------------------------------------===//
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#ifndef CLANG_CIR_LOWERTOLLVM_H
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#define CLANG_CIR_LOWERTOLLVM_H
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#include "mlir/Pass/Pass.h"
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#include <memory>
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namespace llvm {
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class LLVMContext;
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class Module;
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} // namespace llvm
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namespace mlir {
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class ModuleOp;
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} // namespace mlir
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namespace cir {
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namespace direct {
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std::unique_ptr<llvm::Module> lowerDirectlyFromCIRToLLVMIR(
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mlir::ModuleOp M, llvm::LLVMContext &Ctx);
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} // namespace direct
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} // namespace cir
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#endif // CLANG_CIR_LOWERTOLLVM_H

‎clang/lib/CIR/CMakeLists.txt‎

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Original file line numberDiff line numberDiff line change
@@ -5,3 +5,4 @@ add_subdirectory(Dialect)
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add_subdirectory(CodeGen)
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add_subdirectory(FrontendAction)
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add_subdirectory(Interfaces)
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add_subdirectory(Lowering)

‎clang/lib/CIR/FrontendAction/CIRGenAction.cpp‎

Lines changed: 46 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -8,8 +8,10 @@
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#include "clang/CIR/FrontendAction/CIRGenAction.h"
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#include "clang/CIR/CIRGenerator.h"
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#include "clang/CIR/LowerToLLVM.h"
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#include "clang/CodeGen/BackendUtil.h"
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#include "clang/Frontend/CompilerInstance.h"
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#include "llvm/IR/Module.h"
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#include "mlir/IR/MLIRContext.h"
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#include "mlir/IR/OwningOpRef.h"
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@@ -18,12 +20,30 @@ using namespace clang;
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namespace cir {
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static BackendAction
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getBackendActionFromOutputType(CIRGenAction::OutputType Action) {
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switch (Action) {
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case CIRGenAction::OutputType::EmitLLVM:
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return BackendAction::Backend_EmitLL;
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default:
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llvm_unreachable("Unsupported action");
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}
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}
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static std::unique_ptr<llvm::Module> lowerFromCIRToLLVMIR(
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const clang::FrontendOptions &FEOpts, mlir::ModuleOp MLIRModule,
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std::unique_ptr<mlir::MLIRContext> MLIRCtx, llvm::LLVMContext &LLVMCtx) {
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return direct::lowerDirectlyFromCIRToLLVMIR(MLIRModule, LLVMCtx);
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}
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class CIRGenConsumer : public clang::ASTConsumer {
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virtual void anchor();
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CIRGenAction::OutputType Action;
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CompilerInstance &CI;
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std::unique_ptr<raw_pwrite_stream> OutputStream;
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ASTContext *Context{nullptr};
@@ -32,17 +52,12 @@ class CIRGenConsumer : public clang::ASTConsumer {
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public:
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CIRGenConsumer(CIRGenAction::OutputType Action,
35-
DiagnosticsEngine &DiagnosticsEngine,
36-
IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
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const HeaderSearchOptions &HeaderSearchOptions,
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const CodeGenOptions &CodeGenOptions,
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const TargetOptions &TargetOptions,
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const LangOptions &LangOptions,
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const FrontendOptions &FEOptions,
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CompilerInstance &CI,
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std::unique_ptr<raw_pwrite_stream> OS)
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: Action(Action), OutputStream(std::move(OS)), FS(VFS),
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Gen(std::make_unique<CIRGenerator>(DiagnosticsEngine, std::move(VFS),
45-
CodeGenOptions)) {}
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: Action(Action), CI(CI), OutputStream(std::move(OS)),
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FS(&CI.getVirtualFileSystem()),
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Gen(std::make_unique<CIRGenerator>(CI.getDiagnostics(), std::move(FS),
60+
CI.getCodeGenOpts())) {}
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void Initialize(ASTContext &Ctx) override {
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assert(!Context && "initialized multiple times");
@@ -58,6 +73,7 @@ class CIRGenConsumer : public clang::ASTConsumer {
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void HandleTranslationUnit(ASTContext &C) override {
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Gen->HandleTranslationUnit(C);
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mlir::ModuleOp MlirModule = Gen->getModule();
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auto MLIRCtx = Gen->takeContext();
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switch (Action) {
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case CIRGenAction::OutputType::EmitCIR:
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if (OutputStream && MlirModule) {
@@ -66,6 +82,18 @@ class CIRGenConsumer : public clang::ASTConsumer {
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MlirModule->print(*OutputStream, Flags);
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}
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break;
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case CIRGenAction::OutputType::EmitLLVM: {
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llvm::LLVMContext LLVMCtx;
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auto LLVMModule = lowerFromCIRToLLVMIR(CI.getFrontendOpts(), MlirModule,
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std::move(MLIRCtx), LLVMCtx);
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BackendAction BEAction = getBackendActionFromOutputType(Action);
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emitBackendOutput(CI, CI.getCodeGenOpts(),
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C.getTargetInfo().getDataLayoutString(),
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LLVMModule.get(), BEAction, FS,
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std::move(OutputStream));
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break;
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}
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}
7098
}
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};
@@ -84,6 +112,8 @@ getOutputStream(CompilerInstance &CI, StringRef InFile,
84112
switch (Action) {
85113
case CIRGenAction::OutputType::EmitCIR:
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return CI.createDefaultOutputFile(false, InFile, "cir");
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case CIRGenAction::OutputType::EmitLLVM:
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return CI.createDefaultOutputFile(false, InFile, "ll");
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}
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llvm_unreachable("Invalid CIRGenAction::OutputType");
89119
}
@@ -96,13 +126,15 @@ CIRGenAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
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Out = getOutputStream(CI, InFile, Action);
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98128
auto Result = std::make_unique<cir::CIRGenConsumer>(
99-
Action, CI.getDiagnostics(), &CI.getVirtualFileSystem(),
100-
CI.getHeaderSearchOpts(), CI.getCodeGenOpts(), CI.getTargetOpts(),
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CI.getLangOpts(), CI.getFrontendOpts(), std::move(Out));
129+
Action, CI, std::move(Out));
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103131
return Result;
104132
}
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106134
void EmitCIRAction::anchor() {}
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EmitCIRAction::EmitCIRAction(mlir::MLIRContext *MLIRCtx)
108136
: CIRGenAction(OutputType::EmitCIR, MLIRCtx) {}
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138+
void EmitLLVMAction::anchor() {}
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EmitLLVMAction::EmitLLVMAction(mlir::MLIRContext *MLIRCtx)
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: CIRGenAction(OutputType::EmitLLVM, MLIRCtx) {}

‎clang/lib/CIR/FrontendAction/CMakeLists.txt‎

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@@ -12,6 +12,7 @@ add_clang_library(clangCIRFrontendAction
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clangAST
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clangFrontend
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clangCIR
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clangCIRLoweringDirectToLLVM
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MLIRCIR
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MLIRIR
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)

‎clang/lib/CIR/Lowering/CMakeLists.txt‎

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@@ -0,0 +1 @@
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add_subdirectory(DirectToLLVM)

‎clang/lib/CIR/Lowering/DirectToLLVM/CMakeLists.txt‎

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@@ -0,0 +1,8 @@
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set(LLVM_LINK_COMPONENTS
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Core
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Support
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)
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6+
add_clang_library(clangCIRLoweringDirectToLLVM
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LowerToLLVM.cpp
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)

‎clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp‎

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@@ -0,0 +1,41 @@
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//====- LowerToLLVM.cpp - Lowering from CIR to LLVMIR ---------------------===//
2+
//
3+
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4+
// See https://llvm.org/LICENSE.txt for license information.
5+
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6+
//
7+
//===----------------------------------------------------------------------===//
8+
//
9+
// This file implements lowering of CIR operations to LLVMIR.
10+
//
11+
//===----------------------------------------------------------------------===//
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13+
#include "clang/CIR/LowerToLLVM.h"
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15+
#include "mlir/IR/BuiltinOps.h"
16+
#include "mlir/Pass/Pass.h"
17+
#include "mlir/Pass/PassManager.h"
18+
#include "llvm/IR/Module.h"
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#include "llvm/Support/TimeProfiler.h"
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21+
22+
using namespace cir;
23+
using namespace llvm;
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namespace cir {
26+
namespace direct {
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28+
std::unique_ptr<llvm::Module>
29+
lowerDirectlyFromCIRToLLVMIR(mlir::ModuleOp theModule, LLVMContext &llvmCtx) {
30+
llvm::TimeTraceScope scope("lower from CIR to LLVM directly");
31+
32+
auto ModuleName = theModule.getName();
33+
auto llvmModule = std::make_unique<llvm::Module>(ModuleName ? *ModuleName : "CIRToLLVMModule", llvmCtx);
34+
35+
if (!llvmModule)
36+
report_fatal_error("Lowering from LLVMIR dialect to llvm IR failed!");
37+
38+
return llvmModule;
39+
}
40+
} // namespace direct
41+
} // namespace cir

‎clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp‎

Lines changed: 7 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -72,7 +72,13 @@ CreateFrontendBaseAction(CompilerInstance &CI) {
7272
llvm_unreachable("CIR suppport not built into clang");
7373
#endif
7474
case EmitHTML: return std::make_unique<HTMLPrintAction>();
75-
case EmitLLVM: return std::make_unique<EmitLLVMAction>();
75+
case EmitLLVM: {
76+
#if CLANG_ENABLE_CIR
77+
if (UseCIR)
78+
return std::make_unique<cir::EmitLLVMAction>();
79+
#endif
80+
return std::make_unique<EmitLLVMAction>();
81+
}
7682
case EmitLLVMOnly: return std::make_unique<EmitLLVMOnlyAction>();
7783
case EmitCodeGenOnly: return std::make_unique<EmitCodeGenOnlyAction>();
7884
case EmitObj: return std::make_unique<EmitObjAction>();

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