[CIR] Add option to emit MLIR in LLVM dialect.

Jezurko · Jezurko · commit 3af1d49fd6f7 · 2025-02-07T16:10:19.000+01:00
diff --git a/clang/include/clang/CIR/FrontendAction/CIRGenAction.h b/clang/include/clang/CIR/FrontendAction/CIRGenAction.h
@@ -37,6 +37,7 @@ class CIRGenAction : public clang::ASTFrontendAction {
     EmitLLVM,
     EmitBC,
     EmitMLIR,
+    EmitMLIRLLVM,
     EmitObj,
     None
   };
@@ -101,6 +102,13 @@ class EmitMLIRAction : public CIRGenAction {
   EmitMLIRAction(mlir::MLIRContext *mlirCtx = nullptr);
 };
 
+class EmitMLIRLLVMAction : public CIRGenAction {
+  virtual void anchor();
+
+public:
+  EmitMLIRLLVMAction(mlir::MLIRContext *mlirCtx = nullptr);
+};
+
 class EmitLLVMAction : public CIRGenAction {
   virtual void anchor();
 
diff --git a/clang/include/clang/CIR/LowerToLLVM.h b/clang/include/clang/CIR/LowerToLLVM.h
@@ -29,13 +29,19 @@ class ModuleOp;
 namespace cir {
 
 namespace direct {
+mlir::ModuleOp lowerDirectlyFromCIRToLLVMDialect(mlir::ModuleOp theModule,
+                                                 bool disableVerifier = false,
+                                                 bool disableCCLowering = false,
+                                                 bool disableDebugInfo = false);
+
+// Lower directly from pristine CIR to LLVMIR.
 std::unique_ptr<llvm::Module> lowerDirectlyFromCIRToLLVMIR(
     mlir::ModuleOp theModule, llvm::LLVMContext &llvmCtx,
     bool disableVerifier = false, bool disableCCLowering = false,
     bool disableDebugInfo = false);
-}
 
-// Lower directly from pristine CIR to LLVMIR.
+} // namespace direct
+
 std::unique_ptr<llvm::Module>
 lowerFromCIRToMLIRToLLVMIR(mlir::ModuleOp theModule,
                            std::unique_ptr<mlir::MLIRContext> mlirCtx,
diff --git a/clang/include/clang/CIR/LowerToMLIR.h b/clang/include/clang/CIR/LowerToMLIR.h
@@ -12,10 +12,16 @@
 #ifndef CLANG_CIR_LOWERTOMLIR_H
 #define CLANG_CIR_LOWERTOMLIR_H
 
+#include "mlir/Transforms/DialectConversion.h"
+
 namespace cir {
 
 void populateCIRLoopToSCFConversionPatterns(mlir::RewritePatternSet &patterns,
                                             mlir::TypeConverter &converter);
+
+mlir::ModuleOp
+lowerFromCIRToMLIRToLLVMDialect(mlir::ModuleOp theModule,
+                                mlir::MLIRContext *mlirCtx = nullptr);
 } // namespace cir
 
 #endif // CLANG_CIR_LOWERTOMLIR_H_
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
@@ -3121,6 +3121,8 @@ def emit_cir_flat : Flag<["-"], "emit-cir-flat">, Visibility<[ClangOption, CC1Op
   Group<Action_Group>, HelpText<"Similar to -emit-cir but also lowers structured CFG into basic blocks.">;
 def emit_mlir : Flag<["-"], "emit-mlir">, Visibility<[CC1Option]>, Group<Action_Group>,
   HelpText<"Build ASTs and then lower through ClangIR to MLIR, emit the .milr file">;
+def emit_mlir_llvm : Flag<["-"], "emit-mlir-llvm">, Visibility<[CC1Option]>, Group<Action_Group>,
+  HelpText<"Build ASTs and then lower through ClangIR to MLIR LLVM Dialect, emit the .mlir file">;
 /// ClangIR-specific options - END
 
 def flto : Flag<["-"], "flto">,
diff --git a/clang/include/clang/Frontend/FrontendOptions.h b/clang/include/clang/Frontend/FrontendOptions.h
@@ -77,6 +77,9 @@ enum ActionKind {
   /// Emit a .mlir file
   EmitMLIR,
 
+  /// Emit an .mlir file with LLVM dialect
+  EmitMLIRLLVM,
+
   /// Emit a .ll file.
   EmitLLVM,
 
diff --git a/clang/lib/CIR/FrontendAction/CIRGenAction.cpp b/clang/lib/CIR/FrontendAction/CIRGenAction.cpp
@@ -26,6 +26,7 @@
 #include "clang/CIR/CIRToCIRPasses.h"
 #include "clang/CIR/Dialect/IR/CIRDialect.h"
 #include "clang/CIR/LowerToLLVM.h"
+#include "clang/CIR/LowerToMLIR.h"
 #include "clang/CIR/Passes.h"
 #include "clang/CodeGen/BackendUtil.h"
 #include "clang/CodeGen/ModuleBuilder.h"
@@ -260,6 +261,14 @@ class CIRGenConsumer : public clang::ASTConsumer {
       }
     }
 
+    auto printMlirModule = [&](mlir::ModuleOp root) {
+      assert(outputStream && "Why are we here without an output stream?");
+      // FIXME: we cannot roundtrip prettyForm=true right now.
+      mlir::OpPrintingFlags flags;
+      flags.enableDebugInfo(/*enable=*/true, /*prettyForm=*/false);
+      root->print(*outputStream, flags);
+    };
+
     switch (action) {
     case CIRGenAction::OutputType::EmitCIR:
     case CIRGenAction::OutputType::EmitCIRFlat:
@@ -274,11 +283,15 @@ class CIRGenConsumer : public clang::ASTConsumer {
       break;
     case CIRGenAction::OutputType::EmitMLIR: {
       auto loweredMlirModule = lowerFromCIRToMLIR(mlirMod, mlirCtx.get());
-      assert(outputStream && "Why are we here without an output stream?");
-      // FIXME: we cannot roundtrip prettyForm=true right now.
-      mlir::OpPrintingFlags flags;
-      flags.enableDebugInfo(/*enable=*/true, /*prettyForm=*/false);
-      loweredMlirModule->print(*outputStream, flags);
+      printMlirModule(loweredMlirModule);
+      break;
+    }
+    case CIRGenAction::OutputType::EmitMLIRLLVM: {
+      auto loweredMlirModule =
+          feOptions.ClangIRDirectLowering
+              ? direct::lowerDirectlyFromCIRToLLVMDialect(mlirMod)
+              : lowerFromCIRToMLIRToLLVMDialect(mlirMod);
+      printMlirModule(loweredMlirModule);
       break;
     }
     case CIRGenAction::OutputType::EmitLLVM:
@@ -362,6 +375,8 @@ getOutputStream(CompilerInstance &ci, StringRef inFile,
     return ci.createDefaultOutputFile(false, inFile, "cir");
   case CIRGenAction::OutputType::EmitMLIR:
     return ci.createDefaultOutputFile(false, inFile, "mlir");
+  case CIRGenAction::OutputType::EmitMLIRLLVM:
+    return ci.createDefaultOutputFile(false, inFile, "mlir");
   case CIRGenAction::OutputType::EmitLLVM:
     return ci.createDefaultOutputFile(false, inFile, "ll");
   case CIRGenAction::OutputType::EmitBC:
@@ -472,6 +487,10 @@ void EmitMLIRAction::anchor() {}
 EmitMLIRAction::EmitMLIRAction(mlir::MLIRContext *_MLIRContext)
     : CIRGenAction(OutputType::EmitMLIR, _MLIRContext) {}
 
+void EmitMLIRLLVMAction::anchor() {}
+EmitMLIRLLVMAction::EmitMLIRLLVMAction(mlir::MLIRContext *_MLIRContext)
+    : CIRGenAction(OutputType::EmitMLIRLLVM, _MLIRContext) {}
+
 void EmitLLVMAction::anchor() {}
 EmitLLVMAction::EmitLLVMAction(mlir::MLIRContext *_MLIRContext)
     : CIRGenAction(OutputType::EmitLLVM, _MLIRContext) {}
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -4689,11 +4689,11 @@ void populateCIRToLLVMPasses(mlir::OpPassManager &pm, bool useCCLowering) {
 
 extern void registerCIRDialectTranslation(mlir::MLIRContext &context);
 
-std::unique_ptr<llvm::Module>
-lowerDirectlyFromCIRToLLVMIR(mlir::ModuleOp theModule, LLVMContext &llvmCtx,
-                             bool disableVerifier, bool disableCCLowering,
-                             bool disableDebugInfo) {
-  llvm::TimeTraceScope scope("lower from CIR to LLVM directly");
+mlir::ModuleOp lowerDirectlyFromCIRToLLVMDialect(mlir::ModuleOp theModule,
+                                                 bool disableVerifier,
+                                                 bool disableCCLowering,
+                                                 bool disableDebugInfo) {
+  llvm::TimeTraceScope scope("lower from CIR to LLVM Dialect");
 
   mlir::MLIRContext *mlirCtx = theModule.getContext();
   mlir::PassManager pm(mlirCtx);
@@ -4722,6 +4722,20 @@ lowerDirectlyFromCIRToLLVMIR(mlir::ModuleOp theModule, LLVMContext &llvmCtx,
   if (theModule.verify().failed())
     report_fatal_error("Verification of the final LLVMIR dialect failed!");
 
+  return theModule;
+}
+
+std::unique_ptr<llvm::Module>
+lowerDirectlyFromCIRToLLVMIR(mlir::ModuleOp theModule, LLVMContext &llvmCtx,
+                             bool disableVerifier, bool disableCCLowering,
+                             bool disableDebugInfo) {
+  llvm::TimeTraceScope scope("lower from CIR to LLVM directly");
+
+  lowerDirectlyFromCIRToLLVMDialect(theModule, disableVerifier,
+                                    disableCCLowering, disableDebugInfo);
+
+  mlir::MLIRContext *mlirCtx = theModule.getContext();
+
   mlir::registerBuiltinDialectTranslation(*mlirCtx);
   mlir::registerLLVMDialectTranslation(*mlirCtx);
   mlir::registerOpenMPDialectTranslation(*mlirCtx);
diff --git a/clang/lib/CIR/Lowering/ThroughMLIR/LowerCIRToMLIR.cpp b/clang/lib/CIR/Lowering/ThroughMLIR/LowerCIRToMLIR.cpp
@@ -47,6 +47,7 @@
 #include "mlir/Transforms/DialectConversion.h"
 #include "clang/CIR/Dialect/IR/CIRDialect.h"
 #include "clang/CIR/Dialect/IR/CIRTypes.h"
+#include "clang/CIR/LowerToLLVM.h"
 #include "clang/CIR/LowerToMLIR.h"
 #include "clang/CIR/LoweringHelpers.h"
 #include "clang/CIR/Passes.h"
@@ -1458,13 +1459,14 @@ void ConvertCIRToMLIRPass::runOnOperation() {
     signalPassFailure();
 }
 
-std::unique_ptr<llvm::Module>
-lowerFromCIRToMLIRToLLVMIR(mlir::ModuleOp theModule,
-                           std::unique_ptr<mlir::MLIRContext> mlirCtx,
-                           LLVMContext &llvmCtx) {
-  llvm::TimeTraceScope scope("Lower from CIR to MLIR To LLVM");
+mlir::ModuleOp lowerFromCIRToMLIRToLLVMDialect(mlir::ModuleOp theModule,
+                                               mlir::MLIRContext *mlirCtx) {
+  llvm::TimeTraceScope scope("Lower from CIR to MLIR To LLVM Dialect");
+  if (!mlirCtx) {
+    mlirCtx = theModule.getContext();
+  }
 
-  mlir::PassManager pm(mlirCtx.get());
+  mlir::PassManager pm(mlirCtx);
 
   pm.addPass(createConvertCIRToMLIRPass());
   pm.addPass(createConvertMLIRToLLVMPass());
@@ -1478,6 +1480,17 @@ lowerFromCIRToMLIRToLLVMIR(mlir::ModuleOp theModule,
   if (theModule.verify().failed())
     report_fatal_error("Verification of the final LLVMIR dialect failed!");
 
+  return theModule;
+}
+
+std::unique_ptr<llvm::Module>
+lowerFromCIRToMLIRToLLVMIR(mlir::ModuleOp theModule,
+                           std::unique_ptr<mlir::MLIRContext> mlirCtx,
+                           LLVMContext &llvmCtx) {
+  llvm::TimeTraceScope scope("Lower from CIR to MLIR To LLVM");
+
+  lowerFromCIRToMLIRToLLVMDialect(theModule, mlirCtx.get());
+
   mlir::registerBuiltinDialectTranslation(*mlirCtx);
   mlir::registerLLVMDialectTranslation(*mlirCtx);
   mlir::registerOpenMPDialectTranslation(*mlirCtx);
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2738,6 +2738,7 @@ static const auto &getFrontendActionTable() {
       {frontend::EmitCIRFlat, OPT_emit_cir_flat},
       {frontend::EmitCIROnly, OPT_emit_cir_only},
       {frontend::EmitMLIR, OPT_emit_mlir},
+      {frontend::EmitMLIRLLVM, OPT_emit_mlir_llvm},
       {frontend::EmitHTML, OPT_emit_html},
       {frontend::EmitLLVM, OPT_emit_llvm},
       {frontend::EmitLLVMOnly, OPT_emit_llvm_only},
@@ -4669,6 +4670,7 @@ static bool isStrictlyPreprocessorAction(frontend::ActionKind Action) {
   case frontend::EmitCIRFlat:
   case frontend::EmitCIROnly:
   case frontend::EmitMLIR:
+  case frontend::EmitMLIRLLVM:
   case frontend::EmitHTML:
   case frontend::EmitLLVM:
   case frontend::EmitLLVMOnly:
diff --git a/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp b/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp
@@ -99,6 +99,8 @@ CreateFrontendBaseAction(CompilerInstance &CI) {
     return std::make_unique<cir::EmitCIROnlyAction>();
   case EmitMLIR:
     return std::make_unique<cir::EmitMLIRAction>();
+  case EmitMLIRLLVM:
+    return std::make_unique<cir::EmitMLIRLLVMAction>();
 #else
   case EmitCIR:
   case EmitCIRFlat:
