Add MPS delegate (#754)

Summary:
This PR adds MPS Delegate support for ExecuTorch:

To use the MPS delegate, follow the following steps:

* (AOT) Generate an MPSGraph lowered module

```
python3 -m examples.apple.mps.scripts.mps_example --model_name="mv2" --bundled
```

* (RUNTIME) Once the model binary file is generated, use the mps_executor_runner to run the model:

```bash
# Build the mps_executor_runner
rm -rf cmake-out && mkdir cmake-out && cd cmake-out && cmake -DEXECUTORCH_BUILD_MPS=1 -DBUCK2=/tmp/buck2 —trace .. && cmake --build . && cd ..

# Run the bundled program
./cmake-out/examples/apple/mps/mps_executor_runner --model_path mv2_mps_bundled.pte --bundled_program

```

To see more verbose logging on the runtime, you can enable set -DCMAKE_BUILD_TYPE=Debug while building the runner.

An example tutorial can be found under examples/apple/mps/README.md.
iOS instructions to run using the MPSDelegate have been updated in examples/demo-apps/apple_ios/README.md

Note that the mps_executor_runner can be used with any testcase from test_mps.py and is not limited to examples.apple.mps.scripts.mps_example. For example

```
python3 -m unittest backends.apple.mps.test.test_mps --verbose -k test_mps_backend_cumsum
```

Fix MPS delegate through simulator.

Pull Request resolved: #754

Reviewed By: iseeyuan, guangy10

Differential Revision: D50110623

Pulled By: kimishpatel

fbshipit-source-id: 800a1d90776206dfac82fba8d9d2a0b83daf8c31

Author: kulinseth

CMakeLists.txt

@@ -137,6 +137,10 @@ option(EXECUTORCH_BUILD_EXAMPLES "Build the ExecuTorch examples.")
 option(EXECUTORCH_BUILD_XTENSA_EXAMPLE
        "Build the example targeted for the Xtensa Hifi4 DSP" OFF)
 
+# Build mps_executor_runner which depends on MPSGraph framework
+option(EXECUTORCH_BUILD_MPS
+       "Build mps_executor_runner which depends on MPS" OFF)
+
 if(NOT BUCK2)
   set(BUCK2 buck2)
 endif()
@@ -336,6 +340,12 @@ if(EXECUTORCH_BUILD_ARM_BAREMETAL)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backends/arm)
 endif()
 
+option(EXECUTORCH_BUILD_MPS "Build the backends/apple/mps directory" OFF)
+if(EXECUTORCH_BUILD_MPS)
+  add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backends/apple/mps)
+  add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/examples/apple/mps)
+endif()
+
 # Add selective build subdirectory
 if(BUILD_SELECTIVE_BUILD_TEST)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/examples/selective_build)

backends/apple/mps/.clang-format

@@ -0,0 +1,9 @@
+---
+Language: ObjC
+ColumnLimit: 120
+AlignAfterOpenBracket: Align
+ObjCBinPackProtocolList: Auto
+ObjCBlockIndentWidth: 2
+ObjCBreakBeforeNestedBlockParam: true
+ObjCSpaceAfterProperty: false
+ObjCSpaceBeforeProtocolList: false

backends/apple/mps/CMakeLists.txt

@@ -0,0 +1,30 @@
+#
+#  Copyright (c) 2023 Apple Inc. All rights reserved.
+#  Provided subject to the LICENSE file in the top level directory.
+#
+
+cmake_minimum_required(VERSION 3.19)
+
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+if(NOT CMAKE_CXX_STANDARD)
+  set(CMAKE_CXX_STANDARD 17)
+endif()
+
+if(NOT PYTHON_EXECUTABLE)
+  set(PYTHON_EXECUTABLE python3)
+endif()
+
+# Source root directory for executorch.
+if(NOT EXECUTORCH_ROOT)
+  set(EXECUTORCH_ROOT ${CMAKE_CURRENT_SOURCE_DIR}/../../..)
+endif()
+
+set(_common_compile_options -Wno-deprecated-declarations)
+set(_common_include_directories ${EXECUTORCH_ROOT}/..)
+
+list(TRANSFORM _mps_backend__srcs PREPEND "${EXECUTORCH_ROOT}/")
+add_library(mpsdelegate ${_mps_backend__srcs})
+target_link_libraries(mpsdelegate PRIVATE ${_executor_runner_libs})
+target_include_directories(mpsdelegate
+                           PUBLIC ${_common_include_directories})

backends/apple/mps/TARGETS

@@ -0,0 +1,8 @@
+# Any targets that should be shared between fbcode and xplat must be defined in
+# targets.bzl. This file can contain fbcode-only targets.
+
+load(":targets.bzl", "define_common_targets")
+
+oncall("executorch")
+
+define_common_targets()

backends/apple/mps/install_requirements.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+#
+#  Copyright (c) 2023 Apple Inc. All rights reserved.
+#  Provided subject to the LICENSE file in the top level directory.
+#
+
+# Install required python dependencies for using the MPS Backend
+pip install --force-reinstall ninja