[mlir] Add C API for ControlFlow dialect

Add basic C API for the ControlFlow dialect. Follows the format of the other dialects.

Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D121867

mlir/include/mlir-c/Dialect/ControlFlow.h

@@ -0,0 +1,25 @@
+//===-- mlir-c/Dialect/ControlFlow.h - C API for ControlFlow ------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_C_DIALECT_CONTROLFLOW_H
+#define MLIR_C_DIALECT_CONTROLFLOW_H
+
+#include "mlir-c/Registration.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+MLIR_DECLARE_CAPI_DIALECT_REGISTRATION(ControlFlow, cf);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // MLIR_C_DIALECT_CONTROLFLOW_H

mlir/lib/CAPI/Dialect/CMakeLists.txt

@@ -13,6 +13,15 @@ add_mlir_upstream_c_api_library(MLIRCAPIAsync
   MLIRPass
 )
 
+add_mlir_upstream_c_api_library(MLIRCAPIControlFlow
+  ControlFlow.cpp
+
+  PARTIAL_SOURCES_INTENDED
+  LINK_LIBS PUBLIC
+  MLIRCAPIIR
+  MLIRControlFlow
+)
+
 add_mlir_upstream_c_api_library(MLIRCAPIGPU
   GPU.cpp
   GPUPasses.cpp

mlir/lib/CAPI/Dialect/ControlFlow.cpp

@@ -0,0 +1,14 @@
+//===- ControlFlow.cpp - C Interface for ControlFlow dialect --------------===//
+//
+// 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/Dialect/ControlFlow.h"
+#include "mlir/CAPI/Registration.h"
+#include "mlir/Dialect/ControlFlow/IR/ControlFlow.h"
+
+MLIR_DEFINE_CAPI_DIALECT_REGISTRATION(ControlFlow, cf,
+                                      mlir::cf::ControlFlowDialect)