How to Build OpenCL SDK for ANDROID as Static or Shared Library

Question

I am trying to build OpenCL SDK for ANDROID from this source --> https://github.com/KhronosGroup/OpenCL-SDK
I got build ".so" files or ".a" files but they don't not work at all even if they got linked properly.

I think I can't load all the symbols to my ".so" or ".a" files while I building it. I have to load symbols from my device's /system/vendor/lib64/libOpenCL.so. In other words, OPENCL_ICD_LOADER can't detect my device's opencl platform.

My device is a SM-X700. It contains Adreno 730 GPU.

When I open one of the libOpenCL.a or libOpenCL.so files that I got build in text editor, I see somethings like below

!<arch>
/               0           0     0     0       3808      `
���������������������������7��7��7��7��7��7��\��
failed to load library %s
�_�_    �`��T�����_�����OCL_ICD_ENABLE_TRACE�True�true�T�1�KHR ICD trace at %s:%d:
�already loaded vendor %s, nothing to do here
�clGetExtensionFunctionAddress�failed to get function address clGetExtensionFunctionAddress
�clIcdGetPlatformIDsKHR�failed to get extension function address clIcdGetPlatformIDsKHR
�failed clIcdGetPlatformIDs
�failed to allocate memory
�failed get platform handle to library
�successfully added vendor %s with suffix %s

I installed the triplet for arm64-v8a in vcpkg using the link below --> https://learn.microsoft.com/en-us/vcpkg/users/platforms/android

And this is my cmake configuration

cmake -D CMAKE_BUILD_TYPE=Release \
      -D BUILD_TESTING=OFF \
      -D BUILD_DOCS=OFF \
      -D BUILD_EXAMPLES=OFF \
      -D BUILD_TESTS=OFF \
      -D OPENCL_SDK_BUILD_SAMPLES=OFF \
      -D OPENCL_SDK_TEST_SAMPLES=OFF \
      -D CMAKE_C_COMPILER="/home/my_user_name/Android/Sdk/ndk/25.0.8775105/toolchains/llvm/prebuilt/linux-x86_64/bin/clang" \
      -D CMAKE_CXX_COMPILER="/home/my_user_name/Android/Sdk/ndk/25.0.8775105/toolchains/llvm/prebuilt/linux-x86_64/bin/clang++" \
      -D CMAKE_TOOLCHAIN_FILE=/home/my_user_name/vcpkg/scripts/buildsystems/vcpkg.cmake \
      -D VCPKG_CHAINLOAD_TOOLCHAIN_FILE=/home/my_user_name/Android/Sdk/ndk/25.0.8775105/build/cmake/android.toolchain.cmake \
      -D VCPKG_TARGET_TRIPLET=arm64-android \
      -D ANDROID_ABI=arm64-v8a \
      -D ANDROID_PLATFORM=33 \
      -D CMAKE_INSTALL_PREFIX=/home/my_user_name/OPENCL_AARCH64_OUT \
      -D BUILD_SHARED_LIBS=OFF \
      ..

I want to use OpenCL in my c++-native project on Android. Please help me.

I tried to compile other NDK versions below 25.0.8775105

I found someone who struggle with same problem in this link--> https://developer.qualcomm.com/forum/qdn-forums/software/adreno-gpu-sdk/68895

Answer 1

It is not un easy job to do. So first you need to use API < 23

Then you copy libGLES.so and libOpenCL.so from your device to jni/libs armebi-v7a because arm64-v8a is not available on some machine

then during the the onCreate you must check wich librarty are missing.

some library can be accessible using System.loadLibrary but some other will not it depends on the frabicant and the model. In this case you need to copy from the device the needed library to jni/libs armebi-v7a.

In your android.mk file you need to declare for all the library copied to JNI

    # Honnor play
    include $(CLEAR_VARS)
    LOCAL_MODULE := GLES_mali
    LOCAL_SRC_FILES := $(LOCAL_PATH)/arm7/libGLES_mali.so
    include $(PREBUILT_SHARED_LIBRARY)
and LOCAL_ARM_NEON := true   on ARM

in your aplication.mk

APP_STL := gnustl_static
APP_STL := c++_shared
APP_CPPFLAGS := -frtti -fexceptions
APP_ABI := armeabi-v7a
APP_PLATFORM := android-23

but too load the librarie that cannot be loaded throw System.loadLibrary, the librarie that belong too the fabricant, you need too use SharedLibraryLoader.java clas. You can find this on old post in stackoverflow.

It is not an easy job too do and you must do it for every new phonne. And the last problem is thzt your openCL code will not run proprely from ARM to ADRENO whytout some small modification, you will see ;))

You can find a good OpenCL example on github androidcl-master.