Config HOST_C/CXX_COMPILER for cross-compiling.

cmake/cross_compiling/android.cmake

@@ -112,19 +112,19 @@ IF(${CMAKE_VERSION} VERSION_LESS "3.7.0")
     SET(ANDROID_TOOLCHAIN_PREFIX "${ANDROID_TOOLCHAIN_ROOT}/bin/${ANDROID_TOOLCHAIN_NAME}-")
 
     IF(EXISTS "${ANDROID_TOOLCHAIN_PREFIX}gcc")
-        SET(CMAKE_C_COMPILER "${ANDROID_TOOLCHAIN_PREFIX}gcc")
+        SET(CMAKE_C_COMPILER "${ANDROID_TOOLCHAIN_PREFIX}gcc" CACHE PATH "C compiler")
     ELSE()
-        MESSAGE(FATAL_ERROR "Cannot find C compiler: ${ANDROID_TOOLCHAIN_PREFIX}gcc")
+        MESSAGE(FATAL_ERROR "Cannot found C compiler: ${ANDROID_TOOLCHAIN_PREFIX}gcc")
     ENDIF()
 
     IF(EXISTS "${ANDROID_TOOLCHAIN_PREFIX}g++")
-        SET(CMAKE_CXX_COMPILER "${ANDROID_TOOLCHAIN_PREFIX}g++")
+        SET(CMAKE_CXX_COMPILER "${ANDROID_TOOLCHAIN_PREFIX}g++" CACHE PATH "CXX compiler")
     ELSE()
-        MESSAGE(FATAL_ERROR "Cannot find CXX compiler: ${ANDROID_TOOLCHAIN_PREFIX}g++")
+        MESSAGE(FATAL_ERROR "Cannot found CXX compiler: ${ANDROID_TOOLCHAIN_PREFIX}g++")
     ENDIF()
 
     IF(EXISTS "${ANDROID_TOOLCHAIN_PREFIX}gfortran")
-        SET(CMAKE_Fortran_COMPILER "${ANDROID_TOOLCHAIN_PREFIX}gfortran")
+        SET(CMAKE_Fortran_COMPILER "${ANDROID_TOOLCHAIN_PREFIX}gfortran" CACHE PATH "Fortran compiler")
     ENDIF()
 
     # Toolchain and ABI specific flags.

cmake/cross_compiling/host.cmake

@@ -0,0 +1,49 @@
+# Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserve.
+# 
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+# 
+# http://www.apache.org/licenses/LICENSE-2.0
+# 
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# find host C compiler
+IF(HOST_C_COMPILER)
+    SET(HOST_C_COMPILER_NAME ${HOST_C_COMPILER})
+ELSEIF(NOT $ENV{CC} STREQUAL "")
+    SET(HOST_C_COMPILER_NAME $ENV{CC})
+ELSE()
+    SET(HOST_C_COMPILER_NAME cc)
+ENDIF()
+
+GET_FILENAME_COMPONENT(HOST_C_COMPILER_PATH ${HOST_C_COMPILER_NAME} PROGRAM)
+IF(NOT HOST_C_COMPILER_PATH OR NOT EXISTS ${HOST_C_COMPILER_PATH})
+    MESSAGE(FATAL_ERROR "Cannot found host C compiler, set host C compiler:\n"
+            "\tcmake .. -DHOST_C_COMPILER=...")
+ENDIF()
+
+# find host CXX compiler
+IF(HOST_CXX_COMPILER)
+    SET(HOST_CXX_COMPILER_NAME ${HOST_CXX_COMPILER})
+ELSEIF(NOT $ENV{CXX} STREQUAL "")
+    SET(HOST_CXX_COMPILER_NAME $ENV{CXX})
+ELSE()
+    SET(HOST_CXX_COMPILER_NAME c++)
+ENDIF()
+
+GET_FILENAME_COMPONENT(HOST_CXX_COMPILER_PATH ${HOST_CXX_COMPILER_NAME} PROGRAM)
+IF(NOT HOST_CXX_COMPILER_PATH OR NOT EXISTS ${HOST_CXX_COMPILER_PATH})
+    MESSAGE(FATAL_ERROR "Cannot found host CXX compiler, set host CXX compiler:\n"
+            "\tcmake .. -DHOST_CXX_COMPILER=...")
+ENDIF()
+
+SET(HOST_C_COMPILER ${HOST_C_COMPILER_PATH} CACHE PATH "Host C compiler")
+SET(HOST_CXX_COMPILER ${HOST_CXX_COMPILER_PATH} CACHE PATH "Host CXX compiler")
+
+MESSAGE(STATUS "Found host C compiler: " ${HOST_C_COMPILER})
+MESSAGE(STATUS "Found host CXX compiler: " ${HOST_CXX_COMPILER})

cmake/external/openblas.cmake

@@ -57,11 +57,9 @@ IF(NOT ${CBLAS_FOUND})
 
         SET(OPENBLAS_COMMIT "v0.2.19")
         SET(OPENBLAS_ARGS FC=${CMAKE_Fortran_COMPILER} DYNAMIC_ARCH=1 libs netlib)
-        SET(HOST_C_COMPILER ${CMAKE_C_COMPILER})
     ELSE()
         SET(OPENBLAS_COMMIT "b5c96fcfcdc82945502a2303116a64d89985daf5")
-        SET(OPTIONAL_ARGS TARGET=ARMV7 ARM_SOFTFP_ABI=1 NOFORTRAN=1 USE_THREAD=0 libs)
-        SET(HOST_C_COMPILER gcc)
+        SET(OPTIONAL_ARGS HOSTCC=${HOST_C_COMPILER} TARGET=ARMV7 ARM_SOFTFP_ABI=1 NOFORTRAN=1 USE_THREAD=0 libs)
     ENDIF()
 
     ExternalProject_Add(
@@ -72,7 +70,7 @@ IF(NOT ${CBLAS_FOUND})
         PREFIX              ${CBLAS_SOURCES_DIR}
         INSTALL_DIR         ${CBLAS_INSTALL_DIR}
         BUILD_IN_SOURCE     1
-        BUILD_COMMAND       ${CMAKE_MAKE_PROGRAM} CC=${CMAKE_C_COMPILER} HOSTCC=${HOST_C_COMPILER} NO_SHARED=1 ${OPTIONAL_ARGS}
+        BUILD_COMMAND       ${CMAKE_MAKE_PROGRAM} CC=${CMAKE_C_COMPILER} NO_SHARED=1 ${OPTIONAL_ARGS}
         INSTALL_COMMAND     ${CMAKE_MAKE_PROGRAM} install NO_SHARED=1 PREFIX=<INSTALL_DIR>
         UPDATE_COMMAND      ""
         CONFIGURE_COMMAND   ""

cmake/system.cmake

@@ -74,6 +74,7 @@ MESSAGE(STATUS "Found Paddle host system's CPU: ${CPU_CORES} cores")
 
 # configuration for cross-compiling
 IF(DEFINED CMAKE_SYSTEM_NAME)
+    INCLUDE(cross_compiling/host)
     IF(${CMAKE_SYSTEM_NAME} STREQUAL "Android")
         SET(ANDROID TRUE)
         INCLUDE(cross_compiling/android)