[MLIR] Add OpenMP dialect with barrier operation

Summary:
Barrier is a simple operation that takes no arguments and returns
nothing, but implies a side effect (synchronization of all threads)

Reviewers: jdoerfert

Subscribers: mgorny, guansong, mehdi_amini, rriddle, jpienaar, burmako, shauheen, antiagainst, nicolasvasilache, arpith-jacob, mgester, lucyrfox, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D72400

mlir/include/mlir/Dialect/CMakeLists.txt

@@ -4,6 +4,7 @@ add_subdirectory(GPU)
 add_subdirectory(Linalg)
 add_subdirectory(LLVMIR)
 add_subdirectory(LoopOps)
+add_subdirectory(OpenMP)
 add_subdirectory(QuantOps)
 add_subdirectory(SPIRV)
 add_subdirectory(StandardOps)

mlir/include/mlir/Dialect/OpenMP/CMakeLists.txt

@@ -0,0 +1 @@
+add_mlir_dialect(OpenMPOps OpenMPOps)

mlir/include/mlir/Dialect/OpenMP/OpenMPDialect.h

@@ -0,0 +1,35 @@
+//===- OpenMPDialect.h - MLIR Dialect for OpenMP ----------------*- 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 file declares the OpenMP dialect in MLIR.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_DIALECT_OPENMP_OPENMPDIALECT_H_
+#define MLIR_DIALECT_OPENMP_OPENMPDIALECT_H_
+
+#include "mlir/IR/Dialect.h"
+#include "mlir/IR/OpDefinition.h"
+
+namespace mlir {
+namespace omp {
+
+#define GET_OP_CLASSES
+#include "mlir/Dialect/OpenMP/OpenMPOps.h.inc"
+
+class OpenMPDialect : public Dialect {
+public:
+  explicit OpenMPDialect(MLIRContext *context);
+
+  static StringRef getDialectNamespace() { return "omp"; }
+};
+
+} // namespace omp
+} // namespace mlir
+
+#endif // MLIR_DIALECT_OPENMP_OPENMPDIALECT_H_

mlir/include/mlir/Dialect/OpenMP/OpenMPOps.td

@@ -0,0 +1,37 @@
+//===-- OpenMPOps.td - OpenMP dialect operation definitions *- tablegen -*-===//
+//
+// 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 file defines the basic operations for the OpenMP dialect.
+//
+//===----------------------------------------------------------------------===//
+
+
+#ifndef OPENMP_OPS
+#define OPENMP_OPS
+
+include "mlir/IR/OpBase.td"
+
+def OpenMP_Dialect : Dialect {
+  let name = "omp";
+}
+
+class OpenMP_Op<string mnemonic, list<OpTrait> traits = []> :
+      Op<OpenMP_Dialect, mnemonic, traits>;
+
+def BarrierOp : OpenMP_Op<"barrier"> {
+  let summary = "barrier construct";
+  let description = [{
+    The barrier construct specifies an explicit barrier at the point at which
+    the construct appears.
+  }];
+
+  let parser = [{ return success(); }];
+  let printer = [{ p << getOperationName(); }];
+}
+
+#endif // OPENMP_OPS

mlir/lib/Dialect/CMakeLists.txt

@@ -4,6 +4,7 @@ add_subdirectory(GPU)
 add_subdirectory(Linalg)
 add_subdirectory(LLVMIR)
 add_subdirectory(LoopOps)
+add_subdirectory(OpenMP)
 add_subdirectory(QuantOps)
 add_subdirectory(SDBM)
 add_subdirectory(SPIRV)

mlir/lib/Dialect/OpenMP/CMakeLists.txt

@@ -0,0 +1,8 @@
+add_llvm_library(MLIROpenMP
+  IR/OpenMPDialect.cpp
+
+  ADDITIONAL_HEADER_DIRS
+  ${MLIR_MAIN_INCLUDE_DIR}/mlir/Dialect/OpenMP
+  )
+
+add_dependencies(MLIROpenMP MLIROpenMPOpsIncGen)

mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp

@@ -0,0 +1,34 @@
+//===- OpenMPDialect.cpp - MLIR Dialect for OpenMP implementation ---------===//
+//
+// 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 file implements the OpenMP dialect and its operations.
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/OpenMP/OpenMPDialect.h"
+#include "mlir/IR/OpImplementation.h"
+
+using namespace mlir;
+using namespace mlir::omp;
+
+OpenMPDialect::OpenMPDialect(MLIRContext *context)
+    : Dialect(getDialectNamespace(), context) {
+  addOperations<
+#define GET_OP_LIST
+#include "mlir/Dialect/OpenMP/OpenMPOps.cpp.inc"
+      >();
+}
+
+namespace mlir {
+namespace omp {
+#define GET_OP_CLASSES
+#include "mlir/Dialect/OpenMP/OpenMPOps.cpp.inc"
+} // namespace omp
+} // namespace mlir
+
+static DialectRegistration<OpenMPDialect> ompDialect;

mlir/test/Dialect/OpenMP/ops.mlir

@@ -0,0 +1,7 @@
+// RUN: mlir-opt -verify-diagnostics %s | FileCheck %s
+
+func @omp_barrier() -> () {
+  // CHECK: omp.barrier
+  omp.barrier
+  return
+}

mlir/tools/mlir-opt/CMakeLists.txt

@@ -33,6 +33,7 @@ set(LIBS
   MLIRLLVMIR
   MLIRLoopOps
   MLIRNVVMIR
+  MLIROpenMP
   MLIROptMain
   MLIRParser
   MLIRPass