From 36c21bd8237493fbc6a8d88327fd691ea1f3a7e5 Mon Sep 17 00:00:00 2001
From: Anthony Shoumikhin <shoumikhin@meta.com>
Date: Sat, 9 Mar 2024 10:59:18 -0800
Subject: [PATCH] Build Apple extensions with CMake. (#2336)

Summary:
Pull Request resolved: https://github.com/pytorch/executorch/pull/2336
bypass-github-export-checks

Reviewed By: cccclai

Differential Revision: D54711005

fbshipit-source-id: 88dbcba890080d584d0c3f23f2be2e235d2956e9
---
 CMakeLists.txt                                |  4 ++
 build/build_apple_frameworks.sh               |  5 ++-
 extension/apple/CMakeLists.txt                | 45 +++++++++++++++++++
 .../ExecuTorch/Exported/module.modulemap      |  6 +++
 4 files changed, 59 insertions(+), 1 deletion(-)
 create mode 100644 extension/apple/CMakeLists.txt
 create mode 100644 extension/apple/ExecuTorch/Exported/module.modulemap

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 185214c275..2803f5c4be 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -340,6 +340,10 @@ if(EXECUTORCH_BUILD_SDK)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/sdk)
 endif()
 
+if(EXECUTORCH_BUILD_EXTENSION_APPLE)
+  add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/extension/apple)
+endif()
+
 if(EXECUTORCH_BUILD_EXTENSION_DATA_LOADER)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/extension/data_loader)
 endif()
diff --git a/build/build_apple_frameworks.sh b/build/build_apple_frameworks.sh
index c43ac8b568..30e36df136 100755
--- a/build/build_apple_frameworks.sh
+++ b/build/build_apple_frameworks.sh
@@ -22,7 +22,7 @@ MPS=OFF
 PORTABLE=OFF
 XNNPACK=OFF
 HEADERS_PATH="include"
-EXECUTORCH_FRAMEWORK="executorch:libexecutorch.a,libextension_data_loader.a,libextension_module.a:$HEADERS_PATH"
+EXECUTORCH_FRAMEWORK="executorch:libexecutorch.a,libextension_apple.a,libextension_data_loader.a,libextension_module.a:$HEADERS_PATH"
 COREML_FRAMEWORK="coreml_backend:libcoremldelegate.a:"
 MPS_FRAMEWORK="mps_backend:libmpsdelegate.a:"
 PORTABLE_FRAMEWORK="portable_backend:libportable_kernels.a,libportable_ops_lib.a:"
@@ -115,6 +115,7 @@ cmake_build() {
         -DBUCK2="$BUCK2" \
         -DPYTHON_EXECUTABLE="$PYTHON" \
         -DFLATC_EXECUTABLE="$FLATC" \
+        -DEXECUTORCH_BUILD_EXTENSION_APPLE=ON \
         -DEXECUTORCH_BUILD_EXTENSION_DATA_LOADER=ON \
         -DEXECUTORCH_BUILD_EXTENSION_MODULE=ON \
         -DCMAKE_ARCHIVE_OUTPUT_DIRECTORY="$(pwd)" \
@@ -139,6 +140,8 @@ mkdir -p "$HEADERS_PATH"
   //extension/module: \
 | rsync -av --files-from=- "$SOURCE_ROOT_DIR" "$HEADERS_PATH/executorch"
 
+cp "$SOURCE_ROOT_DIR/extension/apple/ExecuTorch/Exported/"{*.h,*.modulemap} "$HEADERS_PATH"
+
 echo "Creating frameworks"
 
 for platform in "${PLATFORMS[@]}"; do
diff --git a/extension/apple/CMakeLists.txt b/extension/apple/CMakeLists.txt
new file mode 100644
index 0000000000..db194270d3
--- /dev/null
+++ b/extension/apple/CMakeLists.txt
@@ -0,0 +1,45 @@
+# 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.
+
+# Please this file formatted by running:
+# ~~~
+# cmake-format --first-comment-is-literal=True CMakeLists.txt
+# ~~~
+
+cmake_minimum_required(VERSION 3.19)
+
+# Source root directory for executorch.
+if(NOT EXECUTORCH_ROOT)
+  set(EXECUTORCH_ROOT ${CMAKE_CURRENT_SOURCE_DIR}/../..)
+endif()
+
+add_library(extension_apple)
+
+set(EXPORTED_SOURCES
+  ExecuTorch/Exported/ExecuTorchLog.mm
+)
+
+target_sources(
+  extension_apple PRIVATE
+  ${EXPORTED_SOURCES}
+)
+
+target_include_directories(
+  extension_apple PUBLIC
+  ExecuTorch/Exported
+)
+
+find_library(FOUNDATION_FRAMEWORK Foundation)
+target_link_libraries(extension_apple
+  PRIVATE
+  executorch
+  ${FOUNDATION_FRAMEWORK}
+)
+
+target_compile_options(extension_apple PUBLIC ${_common_compile_options})
+target_compile_options(extension_apple PRIVATE "-fobjc-arc")
+target_compile_options(extension_apple PRIVATE "-fno-exceptions")
+target_compile_options(extension_apple PRIVATE "-fno-rtti")
diff --git a/extension/apple/ExecuTorch/Exported/module.modulemap b/extension/apple/ExecuTorch/Exported/module.modulemap
new file mode 100644
index 0000000000..cb91d5d4d6
--- /dev/null
+++ b/extension/apple/ExecuTorch/Exported/module.modulemap
@@ -0,0 +1,6 @@
+module ExecuTorch {
+  umbrella header "ExecuTorch.h"
+
+  export *
+  module * { export * }
+}
\ No newline at end of file