Use native cross-compiling support for Android of cmake.

CMakeLists.txt

@@ -12,19 +12,26 @@
 # See the License for the specific language governing permissions and
 # limitations under the License
 
-cmake_minimum_required(VERSION 3.0)
-
-project(paddle CXX C)
-
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake")
 set(PROJ_ROOT ${CMAKE_SOURCE_DIR})
 
+include(system)
+
+if(ANDROID)
+    cmake_minimum_required(VERSION 3.7)
+else()
+    cmake_minimum_required(VERSION 3.0)
+endif()
+
+project(paddle CXX C)
+
 find_package(Sphinx)
-find_package(CUDA QUIET)
+if(NOT CMAKE_CROSSCOMPILING)
+    find_package(CUDA QUIET)
+endif(NOT CMAKE_CROSSCOMPILING)
 find_package(Git REQUIRED)
 find_package(Threads REQUIRED)
 
-include(system)
 include(simd)
 
 ################################ Configurations #######################################
@@ -51,6 +58,17 @@ if(NOT CMAKE_BUILD_TYPE)
       FORCE)
 endif()
 
+if(ANDROID)
+    set(WITH_GPU OFF CACHE STRING
+        "Disable GPU when cross-compiling for Android" FORCE)
+    set(WITH_AVX OFF CACHE STRING
+        "Disable AVX when cross-compiling for Android" FORCE)
+    set(WITH_PYTHON OFF CACHE STRING
+        "Disable PYTHON when cross-compiling for Android" FORCE)
+    set(WITH_RDMA OFF CACHE STRING
+        "Disable RDMA when cross-compiling for Android" FORCE)
+endif(ANDROID)
+
 set(THIRD_PARTY_PATH "${PROJ_ROOT}/third_party" CACHE STRING
   "A path setting third party libraries download & build directories.")
 ########################################################################################

cmake/configure.cmake

@@ -32,15 +32,13 @@ if(NOT WITH_PROFILER)
     add_definitions(-DPADDLE_DISABLE_PROFILER)
 endif(NOT WITH_PROFILER)
 
-if(NEON_FOUND)
-    set(SIMD_FLAG ${NEON_FLAG})
-else(NEON_FOUND)
+if(NOT CMAKE_CROSSCOMPILING)
     if(WITH_AVX)
         set(SIMD_FLAG ${AVX_FLAG})
     else(WITH_AVX)
         set(SIMD_FLAG ${SSE3_FLAG})
     endif(WITH_AVX)
-endif(NEON_FOUND)
+endif()
 
 if(NOT WITH_GPU)
     add_definitions(-DPADDLE_ONLY_CPU)

cmake/external/python.cmake

@@ -219,9 +219,9 @@ ELSE(PYTHONLIBS_FOUND AND PYTHONINTERP_FOUND)
 
 ENDIF(PYTHONLIBS_FOUND AND PYTHONINTERP_FOUND)
 
-INCLUDE_DIRECTORIES(${PYTHON_INCLUDE_DIR})
-INCLUDE_DIRECTORIES(${PYTHON_NUMPY_INCLUDE_DIR})
-
-IF(NOT WITH_PYTHON)
+IF(WITH_PYTHON)
+    INCLUDE_DIRECTORIES(${PYTHON_INCLUDE_DIR})
+    INCLUDE_DIRECTORIES(${PYTHON_NUMPY_INCLUDE_DIR})
+ELSE()
     SET(PYTHON_LIBRARIES "")
 ENDIF()

cmake/flags.cmake

@@ -26,7 +26,7 @@ function(CheckCompilerCXX11Flag)
 endfunction()
 
 CheckCompilerCXX11Flag()
-LIST(APPEND CMAKE_CXX_FLAGS -std=c++11)
+string(APPEND CMAKE_CXX_FLAGS " -std=c++11")
 
 # safe_set_flag
 #

cmake/simd.cmake

@@ -10,16 +10,16 @@ IF(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID
     set(SSE3_FLAG "-msse3")
     SET(AVX_FLAG "-mavx")
     SET(AVX2_FLAG "-mavx2")
-    SET(NEON_FLAG "-pie -fPIE -mfloat-abi=softfp -mfpu=neon")
 ELSEIF(MSVC)
     set(MMX_FLAG "/arch:MMX")
     set(SSE2_FLAG "/arch:SSE2")
     set(SSE3_FLAG "/arch:SSE3")
     SET(AVX_FLAG "/arch:AVX")
     SET(AVX2_FLAG "/arch:AVX2")
-    #SET(NEON_FLAG "")
 ENDIF()
 
+set(CMAKE_REQUIRED_FLAGS_RETAINED ${CMAKE_REQUIRED_FLAGS})
+
 # Check  MMX
 set(CMAKE_REQUIRED_FLAGS ${MMX_FLAG})
 CHECK_CXX_SOURCE_RUNS("
@@ -76,17 +76,5 @@ int main()
     return 0;
 }" AVX2_FOUND)
 
-# Check NEON
-set(CMAKE_REQUIRED_FLAGS ${NEON_FLAG})
-CHECK_CXX_SOURCE_COMPILES("
-#include <arm_neon.h>
-int main()
-{
-    float32x4_t a = {-1.0f, 2.0f, -3.0f, 4.0f};
-    float32x4_t b = {1.0f, 2.0f, 3.0f, 4.0f};
-    float32x4_t c = vaddq_f32(a, b);
-    return 0;
-}" NEON_FOUND)
-
-set(CMAKE_REQUIRED_FLAGS "")
-mark_as_advanced(MMX_FOUND SSE2_FOUND SSE3_FOUND AVX_FOUND AVX2_FOUND NEON_FOUND)
+set(CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS_RETAINED})
+mark_as_advanced(MMX_FOUND SSE2_FOUND SSE3_FOUND AVX_FOUND AVX2_FOUND)

cmake/system.cmake

@@ -67,6 +67,12 @@ MARK_AS_ADVANCED(HOST_SYSTEM CPU_CORES)
 MESSAGE(STATUS "Found Paddle host system: ${HOST_SYSTEM}")
 MESSAGE(STATUS "Found Paddle host system's CPU: ${CPU_CORES} cores")
 
+IF(DEFINED CMAKE_SYSTEM_NAME)
+    IF(${CMAKE_SYSTEM_NAME} STREQUAL "Android")
+        SET(ANDROID TRUE)
+    ENDIF()
+ENDIF()
+
 # external dependencies log output
 SET(EXTERNAL_PROJECT_LOG_ARGS
     LOG_DOWNLOAD    0     # Wrap download in script to log output

cmake/util.cmake

@@ -90,6 +90,10 @@ function(link_paddle_exe TARGET_NAME)
         ${RDMA_LD_FLAGS}
         ${RDMA_LIBS})
 
+    if(ANDROID)
+        target_link_libraries(${TARGET_NAME} log)
+    endif(ANDROID)
+
     add_dependencies(${TARGET_NAME} ${external_project_dependencies})
 endfunction()