[mlir] Re-Add mlirTranslateModuleToLLVMIR to MLIR-C (#73627)

The test was checking something unrelated to what it controlled so it
failed after that part changed, i removed that.

See llvm/llvm-project#73117

Author: edg-l

mlir/include/mlir-c/Target/LLVMIR.h

@@ -0,0 +1,39 @@
+//===-- LLVMIR.h - C Interface for MLIR LLVMIR Target -------------*- C -*-===//
+//
+// 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 header declares the C interface to target LLVMIR with MLIR.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_C_TARGET_LLVMIR_H
+#define MLIR_C_TARGET_LLVMIR_H
+
+#include "mlir-c/IR.h"
+#include "mlir-c/Support.h"
+#include "llvm-c/Support.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/// Translate operation that satisfies LLVM dialect module requirements into an
+/// LLVM IR module living in the given context. This translates operations from
+/// any dilalect that has a registered implementation of
+/// LLVMTranslationDialectInterface.
+///
+/// \returns the generated LLVM IR Module from the translated MLIR module, it is
+/// owned by the caller.
+MLIR_CAPI_EXPORTED LLVMModuleRef
+mlirTranslateModuleToLLVMIR(MlirOperation module, LLVMContextRef context);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // MLIR_C_TARGET_LLVMIR_H

mlir/lib/CAPI/CMakeLists.txt

@@ -14,6 +14,7 @@ add_subdirectory(Interfaces)
 add_subdirectory(IR)
 add_subdirectory(RegisterEverything)
 add_subdirectory(Transforms)
+add_subdirectory(Target)
 
 if(MLIR_ENABLE_EXECUTION_ENGINE)
   add_subdirectory(ExecutionEngine)
@@ -36,4 +37,3 @@ if(MLIR_BUILD_MLIR_C_DYLIB)
     endif()
   endif()
 endif()
-

mlir/lib/CAPI/Target/CMakeLists.txt

@@ -0,0 +1,12 @@
+add_mlir_upstream_c_api_library(MLIRCAPITarget
+  LLVMIR.cpp
+
+  LINK_COMPONENTS
+  Core
+
+  LINK_LIBS PUBLIC
+  MLIRToLLVMIRTranslationRegistration
+  MLIRCAPIIR
+  MLIRLLVMToLLVMIRTranslation
+  MLIRSupport
+)

mlir/lib/CAPI/Target/LLVMIR.cpp

@@ -0,0 +1,36 @@
+//===-- LLVMIR.h - C Interface for MLIR LLVMIR Target ---------------------===//
+//
+// 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 "mlir-c/Target/LLVMIR.h"
+#include "llvm-c/Support.h"
+
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include <memory>
+
+#include "mlir/CAPI/IR.h"
+#include "mlir/CAPI/Support.h"
+#include "mlir/CAPI/Wrap.h"
+#include "mlir/Target/LLVMIR/ModuleTranslation.h"
+
+using namespace mlir;
+
+LLVMModuleRef mlirTranslateModuleToLLVMIR(MlirOperation module,
+                                          LLVMContextRef context) {
+  Operation *moduleOp = unwrap(module);
+
+  llvm::LLVMContext *ctx = llvm::unwrap(context);
+
+  std::unique_ptr<llvm::Module> llvmModule =
+      mlir::translateModuleToLLVMIR(moduleOp, *ctx);
+
+  LLVMModuleRef moduleRef = llvm::wrap(llvmModule.release());
+
+  return moduleRef;
+}