[XLA] Make `HloPass` an interface, NFC

This will allow inheritance from both `HloPassInterface` and `DfsHloVisitor`, so various passes which include a visitor can have handler methods overridden per backend.
Change: 145477041

1 files changed, 41 insertions, 0 deletions

diff --git a/tensorflow/compiler/xla/service/hlo_pass_interface.h b/tensorflow/compiler/xla/service/hlo_pass_interface.h
new file mode 100644
index 0000000000..0cddf8fb8f
--- /dev/null
+++ b/tensorflow/compiler/xla/service/hlo_pass_interface.h
@@ -0,0 +1,41 @@
+/* Copyright 2017 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
+
+    http://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.
+==============================================================================*/
+
+#ifndef TENSORFLOW_COMPILER_XLA_SERVICE_HLO_PASS_INTERFACE_H_
+#define TENSORFLOW_COMPILER_XLA_SERVICE_HLO_PASS_INTERFACE_H_
+
+#include "tensorflow/compiler/xla/service/hlo_module.h"
+#include "tensorflow/compiler/xla/status_macros.h"
+#include "tensorflow/compiler/xla/statusor.h"
+#include "tensorflow/compiler/xla/types.h"
+#include "tensorflow/core/platform/macros.h"
+
+namespace xla {
+
+// Base class for HLO passes. These are used with the HloPassPipeline to
+// organize a sequence of passes.
+class HloPassInterface {
+ public:
+  virtual ~HloPassInterface() = default;
+  virtual tensorflow::StringPiece name() const = 0;
+
+  // Run the pass on the given HLO module.  Return whether it modified the
+  // module.
+  virtual StatusOr<bool> Run(HloModule* module) = 0;
+};
+
+}  // namespace xla
+
+#endif  // TENSORFLOW_COMPILER_XLA_SERVICE_HLO_PASS_INTERFACE_H_