From e64eff1f131eb1ddaf8bb138752df6b2e7f205fe Mon Sep 17 00:00:00 2001
From: Guoyu Wang <62914304+gwang-msft@users.noreply.github.com>
Date: Mon, 8 Mar 2021 22:56:13 -0800
Subject: [PATCH] Enable build with bitcode for iOS (#6905)

* Enable build with bitcode for iOS

* minor format update

* Minor format update

* Addressed CR comments
---
 cmake/CMakeLists.txt              | 27 ++++++++++++++++++++++-----
 cmake/onnxruntime_unittests.cmake | 12 +++++++-----
 2 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
index 5307f4f851..b9d63a163d 100644
--- a/cmake/CMakeLists.txt
+++ b/cmake/CMakeLists.txt
@@ -148,6 +148,8 @@ option(onnxruntime_ENABLE_CPU_FP16_OPS "Build with advanced instruction sets" ON
 option(onnxruntime_USE_NCCL "Build with NCCL support" OFF)
 option(onnxruntime_USE_MPI "Build with MPI support" OFF)
 
+# Enable bitcode for iOS
+option(onnxruntime_ENABLE_BITCODE "Enable bitcode for iOS only" OFF)
 
 # Fuzz test has only been tested with BUILD_SHARED_LIB option,
 # using the MSVC compiler and on windows OS.
@@ -169,6 +171,14 @@ if (onnxruntime_ENABLE_NVTX_PROFILE)
   add_definitions(-DENABLE_NVTX_PROFILE=1)
 endif()
 
+if (onnxruntime_ENABLE_BITCODE)
+  if (NOT (CMAKE_SYSTEM_NAME STREQUAL "iOS"))
+    message(FATAL_ERROR "iOS platform required for onnxruntime_ENABLE_BITCODE")
+  endif()
+  set(CMAKE_XCODE_ATTRIBUTE_ENABLE_BITCODE YES)
+  set(CMAKE_XCODE_ATTRIBUTE_BITCODE_GENERATION_MODE "bitcode")
+endif()
+
 if (onnxruntime_ENABLE_MEMORY_PROFILE)
   add_definitions(-DORT_MEMORY_PROFILE=1)
 endif()
@@ -227,6 +237,13 @@ if (onnxruntime_EXTENDED_MINIMAL_BUILD AND NOT onnxruntime_MINIMAL_BUILD)
   set(onnxruntime_MINIMAL_BUILD ON)
 endif()
 
+# Enable space optimization for gcc/clang
+# Cannot use "-ffunction-sections -fdata-sections" if we enable bitcode (iOS)
+if (NOT MSVC AND NOT onnxruntime_ENABLE_BITCODE)
+  string(APPEND CMAKE_CXX_FLAGS " -ffunction-sections -fdata-sections")
+  string(APPEND CMAKE_C_FLAGS " -ffunction-sections -fdata-sections")
+endif()
+
 # ORT build with as much excluded as possible. Supports ORT flatbuffers models only.
 if (onnxruntime_MINIMAL_BUILD)
   add_compile_definitions(ORT_MINIMAL_BUILD)
@@ -261,7 +278,6 @@ if (onnxruntime_MINIMAL_BUILD)
       string(APPEND CMAKE_SHARED_LINKER_FLAGS " /debug")
     endif()
   else()
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -ffunction-sections -fdata-sections")
     if (CMAKE_HOST_SYSTEM MATCHES "Darwin")
       add_link_options(-Wl, -dead_strip)
     else()
@@ -331,7 +347,8 @@ endif()
 # don't have built-in support for 8 byte atomics
 # Derived from https://github.com/protocolbuffers/protobuf/blob/master/cmake/CMakeLists.txt
 set(onnxruntime_LINK_LIBATOMIC false)
-if (NOT MSVC)
+# We don't need to link libatomic on iOS
+if (NOT MSVC AND NOT (CMAKE_SYSTEM_NAME STREQUAL "iOS"))
   include(CheckCXXSourceCompiles)
   set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
   set(CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS} -std=c++11)
@@ -1028,9 +1045,9 @@ if (WIN32)
     endforeach()
 else()
   add_definitions(-DPLATFORM_POSIX)
-  # Enable warning and enable space optimization in Linux
-  string(APPEND CMAKE_CXX_FLAGS " -Wall -Wextra -ffunction-sections -fdata-sections")
-  string(APPEND CMAKE_C_FLAGS " -Wall -Wextra -ffunction-sections -fdata-sections")
+  # Enable warning
+  string(APPEND CMAKE_CXX_FLAGS " -Wall -Wextra")
+  string(APPEND CMAKE_C_FLAGS " -Wall -Wextra")
 
   if(onnxruntime_DEV_MODE)
     string(APPEND CMAKE_CXX_FLAGS " -Werror")
diff --git a/cmake/onnxruntime_unittests.cmake b/cmake/onnxruntime_unittests.cmake
index e73397b2dc..981f1dacbe 100644
--- a/cmake/onnxruntime_unittests.cmake
+++ b/cmake/onnxruntime_unittests.cmake
@@ -96,7 +96,8 @@ function(AddTest)
       MACOSX_BUNDLE_LONG_VERSION_STRING ${ORT_VERSION}
       MACOSX_BUNDLE_BUNDLE_VERSION ${ORT_VERSION}
       MACOSX_BUNDLE_SHORT_VERSION_STRING ${ORT_VERSION}
-      XCODE_ATTRIBUTE_CLANG_ENABLE_MODULES "YES")
+      XCODE_ATTRIBUTE_CLANG_ENABLE_MODULES "YES"
+      XCODE_ATTRIBUTE_ENABLE_BITCODE "NO")
 
     xctest_add_bundle(${_UT_TARGET}_xc ${_UT_TARGET}
       ${TEST_SRC_DIR}/xctest/ortxctest.m
@@ -120,7 +121,8 @@ function(AddTest)
       MACOSX_BUNDLE_GUI_IDENTIFIER com.onnxruntime.utest.${_UT_TARGET}
       MACOSX_BUNDLE_LONG_VERSION_STRING ${ORT_VERSION}
       MACOSX_BUNDLE_BUNDLE_VERSION ${ORT_VERSION}
-      MACOSX_BUNDLE_SHORT_VERSION_STRING ${ORT_VERSION})
+      MACOSX_BUNDLE_SHORT_VERSION_STRING ${ORT_VERSION}
+      XCODE_ATTRIBUTE_ENABLE_BITCODE "NO")
 
     xctest_add_test(xctest.${_UT_TARGET} ${_UT_TARGET}_xc)
   else()
@@ -814,9 +816,9 @@ if (WIN32)
 endif()
 
 if (onnxruntime_BUILD_SHARED_LIB)
-  set(onnxruntime_perf_test_libs 
-          onnx_test_runner_common onnxruntime_test_utils onnxruntime_common 
-          onnxruntime onnxruntime_flatbuffers  onnx_test_data_proto 
+  set(onnxruntime_perf_test_libs
+          onnx_test_runner_common onnxruntime_test_utils onnxruntime_common
+          onnxruntime onnxruntime_flatbuffers  onnx_test_data_proto
           ${onnxruntime_EXTERNAL_LIBRARIES}
           ${GETOPT_LIB_WIDE} ${SYS_PATH_LIB} ${CMAKE_DL_LIBS})
   if(NOT WIN32)