CMakeLists changes to enable libtorch for Android (#19762)

Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/19762
ghimport-source-id: 287aa7fea4efd38994e14d794123eb2046b91fc0

Differential Revision: D15087653

Pulled By: ljk53

fbshipit-source-id: 4498ff9f7f7903c3e25541184302b811267958e9

.jenkins/pytorch/build.sh

@@ -65,10 +65,9 @@ fi
 if [[ "${BUILD_ENVIRONMENT}" == *-android* ]]; then
   export ANDROID_NDK=/opt/ndk
   build_args=()
-  build_args+=("-DBUILD_BINARY=ON")
-  build_args+=("-DBUILD_TEST=ON")
-  build_args+=("-DUSE_OBSERVERS=ON")
-  build_args+=("-DUSE_ZSTD=ON")
+  build_args+=("-DBUILD_CAFFE2_MOBILE=OFF")
+  build_args+=("-DCMAKE_PREFIX_PATH=$(python -c 'from distutils.sysconfig import get_python_lib; print(get_python_lib())')")
+  build_args+=("-DPYTHON_EXECUTABLE=$(python -c 'import sys; print(sys.executable)')")
   exec ./scripts/build_android.sh "${build_args[@]}" "$@"
 fi
 

CMakeLists.txt

@@ -70,6 +70,7 @@ option(BUILD_CUSTOM_PROTOBUF "Build and use Caffe2's own protobuf under third_pa
 option(BUILD_PYTHON "Build Python binaries" ON)
 option(BUILD_CAFFE2_OPS "Build Caffe2 operators" ON)
 option(BUILD_SHARED_LIBS "Build libcaffe2.so" ON)
+option(BUILD_CAFFE2_MOBILE "Build libcaffe2 for mobile (deprecating)" ON)
 cmake_dependent_option(
     CAFFE2_LINK_LOCAL_PROTOBUF "If set, build protobuf inside libcaffe2.so." ON
     "BUILD_SHARED_LIBS AND BUILD_CUSTOM_PROTOBUF" OFF)
@@ -170,6 +171,26 @@ if (ANDROID OR IOS)
   set(INTERN_BUILD_MOBILE ON)
 endif()
 
+# INTERN_BUILD_ATEN_OPS is used to control whether to build ATen/TH operators.
+# It's disabled for caffe2 mobile library.
+if (INTERN_BUILD_MOBILE AND BUILD_CAFFE2_MOBILE)
+  set(INTERN_BUILD_ATEN_OPS OFF)
+else()
+  set(INTERN_BUILD_ATEN_OPS ON)
+endif()
+
+# BUILD_CAFFE2_MOBILE is the master switch to choose between libcaffe2 v.s. libtorch mobile build.
+# When it's enabled it builds original libcaffe2 mobile library without ATen/TH ops nor TorchScript support;
+# When it's disabled it builds libtorch mobile library, which contains ATen/TH ops and native support for
+# TorchScript model, but doesn't contain not-yet-unified caffe2 ops;
+if (INTERN_BUILD_MOBILE AND NOT BUILD_CAFFE2_MOBILE)
+  set(BUILD_PYTHON OFF)
+  set(BUILD_TORCH ON)
+  set(BUILD_CAFFE2_OPS OFF)
+  set(USE_DISTRIBUTED OFF)
+  set(FEATURE_TORCH_MOBILE ON)
+endif()
+
 if (BUILD_ATEN_ONLY)
   set(BUILD_CAFFE2_OPS OFF)
   set(BUILD_PYTHON OFF)

aten/CMakeLists.txt

@@ -1,14 +1,17 @@
-if (INTERN_BUILD_MOBILE)
+if (NOT INTERN_BUILD_ATEN_OPS)
   return()
 endif()
 
 # Find modules
+if (NOT INTERN_BUILD_MOBILE)
+  list(APPEND CMAKE_MODULE_PATH /usr/lib/x86_64-linux-gnu/)
+  list(APPEND CMAKE_LIBRARY_PATH /usr/lib/x86_64-linux-gnu/ /usr/lib/aarch64-linux-gnu/)
+endif()
+
 list(APPEND CMAKE_MODULE_PATH
-  /usr/lib/x86_64-linux-gnu/
   ${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules
   ${CMAKE_CURRENT_SOURCE_DIR}/../cmake/public
   ${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules_CUDA_fix)
-list(APPEND CMAKE_LIBRARY_PATH /usr/lib/x86_64-linux-gnu/ /usr/lib/aarch64-linux-gnu/)
 
 cmake_policy(SET CMP0012 NEW)
 

aten/src/ATen/CMakeLists.txt

@@ -205,7 +205,7 @@ endif(MKLDNN_FOUND)
 
 list(APPEND ATen_CPU_DEPENDENCY_LIBS cpuinfo)
 
-if(NOT MSVC AND NOT EMSCRIPTEN)
+if(NOT MSVC AND NOT EMSCRIPTEN AND NOT INTERN_BUILD_MOBILE)
   # Preserve values for the main build
   set(__aten_sleef_build_shared_libs ${BUILD_SHARED_LIBS})
   set(__aten_sleef_build_tests ${BUILD_TESTS})

caffe2/CMakeLists.txt

@@ -4,7 +4,7 @@ include(../cmake/Codegen.cmake)
 # ---[ Declare source file lists
 
 # ---[ ATen build
-if (NOT INTERN_BUILD_MOBILE)
+if (INTERN_BUILD_ATEN_OPS)
   set(__caffe2_CMAKE_POSITION_INDEPENDENT_CODE ${CMAKE_POSITION_INDEPENDENT_CODE})
   set(CMAKE_POSITION_INDEPENDENT_CODE ON)
   set(AT_LINK_STYLE INTERFACE)

caffe2/utils/CMakeLists.txt

@@ -19,7 +19,7 @@ list(APPEND Caffe2_CPU_SRCS
 # ---[ threadpool/pthreadpool* is a local modification of the NNPACK
 # pthreadpool with a very similar interface. Neither NNPACK, nor this
 # thread pool supports Windows.
-if (NOT MSVC)
+if (NOT MSVC AND (NOT INTERN_BUILD_MOBILE OR BUILD_CAFFE2_MOBILE))
   set(Caffe2_CPU_SRCS ${Caffe2_CPU_SRCS}
           utils/threadpool/pthreadpool.cc
           utils/threadpool/pthreadpool_impl.cc

cmake/Codegen.cmake

@@ -43,7 +43,7 @@ configure_file(
 install(DIRECTORY ${CMAKE_CURRENT_LIST_DIR}/../caffe2
         DESTINATION include
         FILES_MATCHING PATTERN "*.h")
-if (INTERN_BUILD_MOBILE)
+if (NOT INTERN_BUILD_ATEN_OPS)
   install(DIRECTORY ${CMAKE_CURRENT_LIST_DIR}/../aten/src/ATen/core
           DESTINATION include/ATen
           FILES_MATCHING PATTERN "*.h")
@@ -52,7 +52,7 @@ install(FILES ${CMAKE_BINARY_DIR}/caffe2/core/macros.h
         DESTINATION include/caffe2/core)
 
 # ---[ ATen specific
-if (NOT INTERN_BUILD_MOBILE)
+if (INTERN_BUILD_ATEN_OPS)
   SET(OPT_FLAG "-O3 ")
   IF(MSVC)
     SET(OPT_FLAG "/Ox /fp:strict ")

cmake/Dependencies.cmake

@@ -85,6 +85,8 @@ if(NOT INTERN_BUILD_MOBILE)
   set(BLAS "MKL" CACHE STRING "Selected BLAS library")
 else()
   set(BLAS "Eigen" CACHE STRING "Selected BLAS library")
+  set(AT_MKLDNN_ENABLED 0)
+  set(AT_MKL_ENABLED 0)
 endif()
 set_property(CACHE BLAS PROPERTY STRINGS "Eigen;ATLAS;OpenBLAS;MKL;vecLib")
 message(STATUS "Trying to find preferred BLAS backend of choice: " ${BLAS})

cmake/Summary.cmake

@@ -20,6 +20,7 @@ function (caffe2_print_configuration_summary)
 
   message(STATUS "  TORCH_VERSION         : ${TORCH_VERSION}")
   message(STATUS "  CAFFE2_VERSION        : ${CAFFE2_VERSION}")
+  message(STATUS "  BUILD_CAFFE2_MOBILE   : ${BUILD_CAFFE2_MOBILE}")
   message(STATUS "  BUILD_ATEN_ONLY       : ${BUILD_ATEN_ONLY}")
   message(STATUS "  BUILD_BINARY          : ${BUILD_BINARY}")
   message(STATUS "  BUILD_CUSTOM_PROTOBUF : ${BUILD_CUSTOM_PROTOBUF}")
@@ -44,6 +45,8 @@ function (caffe2_print_configuration_summary)
   message(STATUS "  BUILD_SHARED_LIBS     : ${BUILD_SHARED_LIBS}")
   message(STATUS "  BUILD_TEST            : ${BUILD_TEST}")
 
+  message(STATUS "  INTERN_BUILD_MOBILE   : ${INTERN_BUILD_MOBILE}")
+
   message(STATUS "  USE_ASAN              : ${USE_ASAN}")
   message(STATUS "  USE_CUDA              : ${USE_CUDA}")
   if(${USE_CUDA})

cmake/TorchConfig.cmake.in

@@ -40,11 +40,19 @@ if (@BUILD_SHARED_LIBS@)
   find_package(Caffe2 REQUIRED PATHS ${CMAKE_CURRENT_LIST_DIR}/../Caffe2)
 endif()
 
+if (NOT ANDROID)
   find_library(TORCH_LIBRARY torch PATHS "${TORCH_INSTALL_PREFIX}/lib")
+else()
+  find_library(TORCH_LIBRARY NO_CMAKE_FIND_ROOT_PATH torch PATHS "${TORCH_INSTALL_PREFIX}/lib")
+endif()
 add_library(torch UNKNOWN IMPORTED)
 set(TORCH_LIBRARIES torch ${Caffe2_MAIN_LIBS})
 
+if (NOT ANDROID)
   find_library(C10_LIBRARY c10 PATHS "${TORCH_INSTALL_PREFIX}/lib")
+else()
+  find_library(C10_LIBRARY c10 NO_CMAKE_FIND_ROOT_PATH PATHS "${TORCH_INSTALL_PREFIX}/lib")
+endif()
 list(APPEND TORCH_LIBRARIES ${C10_LIBRARY})
 
 if (@USE_CUDA@)