移植opencv3.1.0到hi3516a

移植opencv3.1.0到hi3516a

参考文章：

http://stackoverflow.com/questions/14810135/erro-while-cross-compile-opencv-program-for-arm

http://blog.csdn.net/pangdegui/article/details/42716829

http://www.cnblogs.com/rickyk/p/3875334.html

https://cmake.org/cmake-tutorial/

https://cmake.org/Wiki/CMake_Cross_Compiling

一、交叉编译opencv3.1.0

1、修改cmake文件
在源码的platforms下已经有对各平台的交叉编译支持，我们只需要做一些简单的修改。

[zzz@localhost platforms]$ pwd
/home/zzz/software/opencv-3.1.0/platforms
[zzz@localhost platforms]$ ll
total 28
drwxr-xr-x. 4 zzz zzz 4096 Dec 18 23:02 android
drwxr-xr-x. 3 zzz zzz 4096 Dec 18 23:02 ios
drwxr-xr-x. 4 zzz zzz 4096 Jan 22 17:24 linux
drwxr-xr-x. 2 zzz zzz 4096 Dec 18 23:02 osx
-rw-r--r--. 1 zzz zzz  323 Dec 18 23:02 readme.txt
drwxr-xr-x. 2 zzz zzz 4096 Dec 18 23:02 scripts
drwxr-xr-x. 2 zzz zzz 4096 Dec 18 23:02 winrt

我们的目标是交叉编译到arm上，那么就进入到linux下：

[zzz@localhost linux]$ pwd
/home/zzz/software/opencv-3.1.0/platforms/linux
[zzz@localhost linux]$ ll
total 20
-rw-r--r--.  1 zzz zzz 4196 Jan 22 16:35 arm-gnueabi.toolchain.cmake
...

arm-gnueabi.toolchain.cmake指明了交叉编译的一些路径等设置，我们根据实际情况对其进行适当修改：

set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_VERSION 1)
set(CMAKE_SYSTEM_PROCESSOR arm-hisiv300-linux-gnueabi)

set(GCC_COMPILER_VERSION "4.6" CACHE STRING "GCC Compiler version")

set(FLOAT_ABI_SUFFIX "")
if (NOT SOFTFP)
    set(FLOAT_ABI_SUFFIX "hf")
endif()

 #CROSS COMPILE SETTING
set(TOOLCHAIN_DIR "/opt/hisi-linux/x86-arm/arm-hisiv300-linux/")
set(CMAKE_C_COMPILER "/opt/hisi-linux/x86-arm/arm-hisiv300-linux/bin/arm-hisiv300-linux-uclibcgnueabi-gcc")
set(CMAKE_CXX_COMPILER "/opt/hisi-linux/x86-arm/arm-hisiv300-linux/bin/arm-hisiv300-linux-uclibcgnueabi-g++")
set(CMAKE_FIND_ROOT_PATH /opt/hisi-linux/ /opt/hisi-linux/x86-arm/arm-hisiv300-linux/)
set(ARM_LINUX_SYSROOT /opt/hisi-linux/x86-arm/arm-hisiv300-linux/ CACHE PATH "ARM cross compile system root")

MESSAGE(STATUS "This is cross compile dir --->"$(CMAKE_C_COMPILER))




#find_program(CMAKE_C_COMPILER NAMES arm-linux-gnueabi${FLOAT_ABI_SUFFIX}-gcc-${GCC_COMPILER_VERSION})
#find_program(CMAKE_CXX_COMPILER NAMES arm-linux-gnueabi${FLOAT_ABI_SUFFIX}-g++-${GCC_COMPILER_VERSION})
#set(ARM_LINUX_SYSROOT /usr/arm-linux-gnueabi${FLOAT_ABI_SUFFIX} CACHE PATH "ARM cross compilation system root")

#set(CMAKE_CXX_FLAGS           ""                    CACHE STRING "c++ flags")
#set(CMAKE_C_FLAGS             ""                    CACHE STRING "c flags")
#set(CMAKE_SHARED_LINKER_FLAGS ""                    CACHE STRING "shared linker flags")
#set(CMAKE_MODULE_LINKER_FLAGS ""                    CACHE STRING "module linker flags")
#set(CMAKE_EXE_LINKER_FLAGS    "-Wl,-z,nocopyreloc"  CACHE STRING "executable linker flags")

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mthumb -fdata-sections -Wa,--noexecstack -fsigned-char -Wno-psabi")
set(CMAKE_C_FLAGS   "${CMAKE_C_FLAGS} -mthumb -fdata-sections -Wa,--noexecstack -fsigned-char -Wno-psabi")

set(CMAKE_SHARED_LINKER_FLAGS "-Wl,--fix-cortex-a8 -Wl,--no-undefined -Wl,--gc-sections -Wl,-z,noexecstack -Wl,-z,relro -Wl,-z,now ${CMAKE_SHARED_LINKER_FLAGS}")
set(CMAKE_MODULE_LINKER_FLAGS "-Wl,--fix-cortex-a8 -Wl,--no-undefined -Wl,--gc-sections -Wl,-z,noexecstack -Wl,-z,relro -Wl,-z,now ${CMAKE_MODULE_LINKER_FLAGS}")
set(CMAKE_EXE_LINKER_FLAGS    "-Wl,--fix-cortex-a8 -Wl,--no-undefined -Wl,--gc-sections -Wl,-z,noexecstack -Wl,-z,relro -Wl,-z,now ${CMAKE_EXE_LINKER_FLAGS}")

if(USE_NEON)
  message(WARNING "You use obsolete variable USE_NEON to enable NEON instruction set. Use -DENABLE_NEON=ON instead." )
  set(ENABLE_NEON TRUE)
elseif(USE_VFPV3)
  message(WARNING "You use obsolete variable USE_VFPV3 to enable VFPV3 instruction set. Use -DENABLE_VFPV3=ON instead." )
  set(ENABLE_VFPV3 TRUE)
endif()

#set(CMAKE_FIND_ROOT_PATH ${CMAKE_FIND_ROOT_PATH} ${ARM_LINUX_SYSROOT})

if(EXISTS ${CUDA_TOOLKIT_ROOT_DIR})
    set(CMAKE_FIND_ROOT_PATH ${CMAKE_FIND_ROOT_PATH} ${CUDA_TOOLKIT_ROOT_DIR})
endif()

set( CMAKE_SKIP_RPATH TRUE CACHE BOOL "If set, runtime paths are not added when using shared libraries." )
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM ONLY)

# macro to find programs on the host OS
macro( find_host_program )
 set( CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER )
 set( CMAKE_FIND_ROOT_PATH_MODE_LIBRARY NEVER )
 set( CMAKE_FIND_ROOT_PATH_MODE_INCLUDE NEVER )
 if( CMAKE_HOST_WIN32 )
  SET( WIN32 1 )
  SET( UNIX )
 elseif( CMAKE_HOST_APPLE )
  SET( APPLE 1 )
  SET( UNIX )
 endif()
 find_program( ${ARGN} )
 SET( WIN32 )
 SET( APPLE )
 SET( UNIX 1 )
 set( CMAKE_FIND_ROOT_PATH_MODE_PROGRAM ONLY )
 set( CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY )
 set( CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY )
endmacro()

# macro to find packages on the host OS
macro( find_host_package )
 set( CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER )
 set( CMAKE_FIND_ROOT_PATH_MODE_LIBRARY NEVER )
 set( CMAKE_FIND_ROOT_PATH_MODE_INCLUDE NEVER )
 if( CMAKE_HOST_WIN32 )
  SET( WIN32 1 )
  SET( UNIX )
 elseif( CMAKE_HOST_APPLE )
  SET( APPLE 1 )
  SET( UNIX )
 endif()
 find_package( ${ARGN} )
 SET( WIN32 )
 SET( APPLE )
 SET( UNIX 1 )
 set( CMAKE_FIND_ROOT_PATH_MODE_PROGRAM ONLY )
 set( CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY )
 set( CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY )
endmacro()

2、交叉编译
设置好了以后，开始进行交叉编译：
建立好执行cmake的路径:build_softfp，建立好编译后的安装路径：install_dir

[zzz@localhost linux]$ ll
total 20
-rw-r--r--.  1 zzz zzz 4196 Jan 22 16:35 arm-gnueabi.toolchain.cmake
drwxrwxr-x. 15 zzz zzz 4096 Jan 22 16:38 build_softfp
drwxrwxr-x.  6 zzz zzz 4096 Jan 22 15:51 install_dir

执行：

[zzz@localhost build_softfp]$ pwd
/home/zzz/software/opencv-3.1.0/platforms/linux/build_softfp
[zzz@localhost build_softfp]$ cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=../install_dir/ -D SOFTFP=ON -D ENABLE_NEON=ON -D CMAKE_TOOLCHAIN_FILE=../arm-gnueabi.toolchain.cmake ../../../

等待10几分钟。

二、编写测试程序

1、程序内容
简单测试对图片的加载：

#include 
#include 
#include 

using namespace std;
using namespace cv;
int main(int argc,char* argv[]){

    string path="/home/zzz/facedata/lena.jpg";


     Mat image = imread( path, 1 );

     if(image.isContinuous()){
         cout<<"read picture successfully!"<else{
         cout<<"fail to read picture!"<return 0;

}

2、编译
CMakeLists.txt:

# this is required
set(CMAKE_SYSTEM_NAME Linux)

set(CMAKE_FIND_ROOT_PATH /opt/hisi-linux/ /opt/hisi-linux/x86-arm/arm-hisiv300-linux/)
set(ARM_LINUX_SYSROOT /opt/hisi-linux/x86-arm/arm-hisiv300-linux/ CACHE PATH "ARM cross compile system root")


# search for programs in the build host directories (not necessary)
SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
# for libraries and headers in the target directories
SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

set(TOOLCHAIN_DIR "/opt/hisi-linux/x86-arm/arm-hisiv300-linux/")

set(CMAKE_C_COMPILER "/opt/hisi-linux/x86-arm/arm-hisiv300-linux/bin/arm-hisiv300-linux-uclibcgnueabi-gcc")
set(CMAKE_CXX_COMPILER "/opt/hisi-linux/x86-arm/arm-hisiv300-linux/bin/arm-hisiv300-linux-uclibcgnueabi-g++")


set(CMAKE_VERBOSE_MAKEFILE ON)


cmake_minimum_required(VERSION 2.8)
project( LoadImage )


set(OpenCV_DIR /home/zzz/software/opencv-3.1.0/platforms/linux/build_softfp/)
include_directories(/home/zzz/software/opencv-3.1.0/platforms/linux/install_dir/include)

#set(OpenCV_DIR /home/zzz/software/opencv-2.4.9/release)
#include_directories(/home/zzz/software/opencv-2.4.9/build/include)

find_package( OpenCV REQUIRED )
add_executable( LoadImage LoadImage.cpp )
target_link_libraries( LoadImage ${OpenCV_LIBS} )

可以把上半部分的内容抽取出来，作为交叉编译的指示文件：

# this is required
set(CMAKE_SYSTEM_NAME Linux)

set(CMAKE_FIND_ROOT_PATH /opt/hisi-linux/ /opt/hisi-linux/x86-arm/arm-hisiv300-linux/)
set(ARM_LINUX_SYSROOT /opt/hisi-linux/x86-arm/arm-hisiv300-linux/ CACHE PATH "ARM cross compile system root")


# search for programs in the build host directories (not necessary)
SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
# for libraries and headers in the target directories
SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

set(TOOLCHAIN_DIR "/opt/hisi-linux/x86-arm/arm-hisiv300-linux/")

set(CMAKE_C_COMPILER "/opt/hisi-linux/x86-arm/arm-hisiv300-linux/bin/arm-hisiv300-linux-uclibcgnueabi-gcc")
set(CMAKE_CXX_COMPILER "/opt/hisi-linux/x86-arm/arm-hisiv300-linux/bin/arm-hisiv300-linux-uclibcgnueabi-g++")


set(CMAKE_VERBOSE_MAKEFILE ON)

执行如下：

[zzz@localhost basictest]$ cmake .
-- The C compiler identification is GNU 4.8.3
-- The CXX compiler identification is GNU 4.8.3
-- Check for working C compiler: /opt/hisi-linux/x86-arm/arm-hisiv300-linux/bin/arm-hisiv300-linux-uclibcgnueabi-gcc
-- Check for working C compiler: /opt/hisi-linux/x86-arm/arm-hisiv300-linux/bin/arm-hisiv300-linux-uclibcgnueabi-gcc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /opt/hisi-linux/x86-arm/arm-hisiv300-linux/bin/arm-hisiv300-linux-uclibcgnueabi-g++
-- Check for working CXX compiler: /opt/hisi-linux/x86-arm/arm-hisiv300-linux/bin/arm-hisiv300-linux-uclibcgnueabi-g++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Configuring done
-- Generating done
-- Build files have been written to: /home/zzz/workspace/arm-opencv3.1.0/src/basictest
[zzz@localhost basictest]$ make
Scanning dependencies of target LoadImage
[100%] Building CXX object CMakeFiles/LoadImage.dir/LoadImage.cpp.o
Linking CXX executable LoadImage
[100%] Built target LoadImage
[zzz@localhost basictest]$ 

三、在板上运行
需要设置好LD_LIBRARY_PATH，使其也指向一开始生成的opencv的库文件路径，或者直接将这些库拷贝到LD_LIBRARY_PATH指定的当前路径中。

四、问题
一开始没有设定好cmake的交叉编译设置，导致在编译测试程序的时候，使用的是系统的c++编译器在编译链接，结果提示无法读取opencv的so的符号等。所以对cmake的设置要在实践中慢慢掌握全面一些。

后记（2016-1-28）：
由于使用的板子有浮点运算单元以及neon，但是上面的编译脚本没有使用相关的参数，包括编译opencv的库以及编译自己的执行程序时都没有用上。因此，编译出来的程序没有用上硬件浮点单元的特性。需要进行修改：
1、修改opencv的交叉编译脚本
主要是设置:

27 
 28 set(CMAKE_CXX_FLAGS           "-mthumb -mcpu=cortex-a7 -mfloat-abi=softfp -mfpu=neon-vfpv4 -mno-unaligned-access -fno-aggressi    ve-loop-optimizations"     CACHE STRING "c++ flags")
 29 set(CMAKE_C_FLAGS             "${CMAKE_CXX_FLAGS}"                    CACHE STRING "c flags")
 30 set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_CXX_FLAGS}"                    CACHE STRING "shared linker flags")
 31 set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_CXX_FLAGS}"                    CACHE STRING "module linker flags")
 32 set(CMAKE_EXE_LINKER_FLAGS    "${CMAKE_CXX_FLAGS} -Wl,-z,nocopyreloc"  CACHE STRING "executable linker flags")
 33 
 34 #set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mthumb -fdata-sections -Wa,--noexecstack -fsigned-char -Wno-psabi")
 35 #set(CMAKE_C_FLAGS   "${CMAKE_C_FLAGS} -mthumb -fdata-sections -Wa,--noexecstack -fsigned-char -Wno-psabi")
 36 
 37 #set(CMAKE_SHARED_LINKER_FLAGS "-Wl,--fix-cortex-a8 -Wl,--no-undefined -Wl,--gc-sections -Wl,-z,noexecstack -Wl,-z,relro -Wl,-    z,now ${CMAKE_SHARED_LINKER_FLAGS}")
 38 #set(CMAKE_MODULE_LINKER_FLAGS "-Wl,--fix-cortex-a8 -Wl,--no-undefined -Wl,--gc-sections -Wl,-z,noexecstack -Wl,-z,relro -Wl,-    z,now ${CMAKE_MODULE_LINKER_FLAGS}")
 39 #set(CMAKE_EXE_LINKER_FLAGS    "-Wl,--fix-cortex-a8 -Wl,--no-undefined -Wl,--gc-sections -Wl,-z,noexecstack -Wl,-z,relro -Wl,-    z,now ${CMAKE_EXE_LINKER_FLAGS}")
 40 

我这里只需要生成so，是否只需要设置CMAKE_SHARED_LINKER_FLAGS这个就可以了？

2、编译出来的so的情况：

[zzz@localhost build_softfp]$ cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=../install_dir/ -D SOFTFP=ON -DENABLE_NEON=ON -D CMAKE_TOOLCHAIN_FILE=../arm-gnueabi.toolchain.cmake ../../../


[zzz@localhost build_softfp]$ readelf -a lib/libopencv_imgproc.so.2.4.9 
...
Attribute Section: aeabi
File Attributes
  Tag_CPU_name: "Cortex-A7"
  Tag_CPU_arch: v7
  Tag_CPU_arch_profile: Application
  Tag_ARM_ISA_use: Yes
  Tag_THUMB_ISA_use: Thumb-2
  Tag_FP_arch: VFPv4
  Tag_Advanced_SIMD_arch: NEONv1 with Fused-MAC
  Tag_ABI_PCS_wchar_t: 4
  Tag_ABI_FP_denormal: Needed
  Tag_ABI_FP_exceptions: Needed
  Tag_ABI_FP_number_model: IEEE 754
  Tag_ABI_align_needed: 8-byte
  Tag_ABI_enum_size: int
  Tag_ABI_HardFP_use: SP and DP
  Tag_CPU_unaligned_access: v6
  Tag_MPextension_use: Allowed
  Tag_DIV_use: Allowed in v7-A with integer division extension
  Tag_Virtualization_use: TrustZone and Virtualization Extensions
[zzz@localhost build_softfp]$ 

我加了一个-DENABLE_NEON=ON，不加也可以。

3、修改执行程序的脚本
在toolchainfile里增加：

set(CMAKE_CXX_FLAGS           "-mthumb -mcpu=cortex-a7 -mfloat-abi=softfp -mfpu=neon-vfpv4 -mno-unaligned-access -fno-aggressive-loop-optimizations"     CACHE STRING "c++ flags")
set(CMAKE_C_FLAGS             "${CMAKE_CXX_FLAGS}"                    CACHE STRING "c flags")
set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_CXX_FLAGS}"                    CACHE STRING "shared linker flags")
set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_CXX_FLAGS}"                    CACHE STRING "module linker flags")
set(CMAKE_EXE_LINKER_FLAGS    "${CMAKE_CXX_FLAGS} -Wl,-z,nocopyreloc"  CACHE STRING "executable linker flags")

经过测试，其实不设置CMAEK_CXX_FLAGS,CMAKE_C_FLAGS及其他，只设置CMAKE_EXE_LINKER_FLAGS，都能达到目标。
产生的exe的情况：

Attribute Section: aeabi
File Attributes
  Tag_CPU_name: "Cortex-A7"
  Tag_CPU_arch: v7
  Tag_CPU_arch_profile: Application
  Tag_ARM_ISA_use: Yes
  Tag_THUMB_ISA_use: Thumb-2
  Tag_FP_arch: VFPv4
  Tag_Advanced_SIMD_arch: NEONv1 with Fused-MAC
  Tag_ABI_PCS_wchar_t: 4
  Tag_ABI_FP_denormal: Needed
  Tag_ABI_FP_exceptions: Needed
  Tag_ABI_FP_number_model: IEEE 754
  Tag_ABI_align_needed: 8-byte
  Tag_ABI_enum_size: int
  Tag_ABI_HardFP_use: SP and DP
  Tag_CPU_unaligned_access: v6
  Tag_MPextension_use: Allowed
  Tag_DIV_use: Allowed in v7-A with integer division extension
  Tag_Virtualization_use: TrustZone and Virtualization Extensions

4、弄明白cmake的几个变量的含义