Add backend runtime context (#209)

Summary:

Add backend runtime context. Items to be added there:
- Event tracer
- temp allocator

The signature breaking change will be in D48872100

Reviewed By: tarun292, dbort

Differential Revision: D48872102

Author: cccclai

runtime/backend/backend_execution_context.h

@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+namespace torch {
+namespace executor {
+
+/**
+ * BackendExecutionContext will be used to inject run time context.
+ * The current plan is to add temp allocator and event tracer (for profiling) as
+ * part of the runtime context.
+ */
+class BackendExecutionContext final {};
+
+} // namespace executor
+} // namespace torch

runtime/backend/targets.bzl

@@ -15,6 +15,7 @@ def define_common_targets():
                 "backend_registry.cpp",
             ],
             exported_headers = [
+                "backend_execution_context.h",
                 "backend_registry.h",
             ],
             preprocessor_flags = ["-DUSE_ATEN_LIB"] if aten_mode else [],