Add Bazel build configuration to MLIR HLO standalone repo.

Tested that this works in OSS in tree with `bazel build //...` and as a submodule in IREE.

PiperOrigin-RevId: 347919106

.bazelrc

@@ -0,0 +1,15 @@
+# Copyright 2020 The TensorFlow Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+build --cxxopt=-std=c++14
+build --host_cxxopt=-std=c++14

.gitignore

@@ -1,4 +1,4 @@
 build
 llvm-project
 llvm-build
-
+bazel-*

WORKSPACE

@@ -0,0 +1,57 @@
+# Copyright 2020 The TensorFlow Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Workspace for MLIR HLO."""
+
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+LLVM_COMMIT = "7aeb3804c46cc6c8f291415ca09ae34021301eb8"
+
+LLVM_SHA256 = "945718051c37e55fc3aa79f4752dbcb22240ed19bc8037d41b4d461acd34c000"
+
+LLVM_BAZEL_TAG = "llvm-project-{commit}".format(commit = LLVM_COMMIT)
+
+http_archive(
+    name = "llvm-bazel",
+    strip_prefix = "llvm-bazel-{tag}/llvm-bazel".format(tag = LLVM_BAZEL_TAG),
+    url = "https://github.com/google/llvm-bazel/archive/{tag}.tar.gz".format(tag = LLVM_BAZEL_TAG),
+)
+
+load("@llvm-bazel//:terminfo.bzl", "llvm_terminfo_disable")
+load("@llvm-bazel//:zlib.bzl", "llvm_zlib_disable")
+load("@llvm-bazel//:configure.bzl", "llvm_configure")
+
+http_archive(
+    name = "llvm-project-raw",
+    build_file_content = "#empty",
+    sha256 = LLVM_SHA256,
+    strip_prefix = "llvm-project-{commit}".format(commit = LLVM_COMMIT),
+    urls = [
+        "https://storage.googleapis.com/mirror.tensorflow.org/github.com/llvm/llvm-project/archive/{commit}.tar.gz".format(commit = LLVM_COMMIT),
+        "https://github.com/llvm/llvm-project/archive/{commit}.tar.gz".format(commit = LLVM_COMMIT),
+    ],
+)
+
+llvm_terminfo_disable(
+    name = "llvm_terminfo",
+)
+
+llvm_zlib_disable(
+    name = "llvm_zlib",
+)
+
+llvm_configure(
+    name = "llvm-project",
+    src_path = ".",
+    src_workspace = "@llvm-project-raw//:WORKSPACE",
+)