These are step by step instructions for building the Arm NN shim and support library for NNAPI. This work is currently in an experimental phase.
The following are required to build the Arm NN support library
The following is required to build the Arm NN shim
android12-s1-release
Set environment variables
export WORKING_DIR=<path to where the Arm NN source code, clframework and aosp repos will be cloned> export AOSP_ROOT=<path to the root of Android tree where the shim will be built> export AOSP_MODULES_ROOT=<path to where AOSP modules will be cloned i.e. $WORKING_DIR/aosp> export ARMNN_BUILD_DIR=<path to the Arm NN build directory i.e. $WORKING_DIR/build> export NDK=<path to>android-ndk-r25 export NDK_TOOLCHAIN_ROOT=$NDK/toolchains/llvm/prebuilt/linux-x86_64 export PATH=$NDK_TOOLCHAIN_ROOT/bin/:$PATH export FLATBUFFERS_ANDROID_BUILD=<path to flatbuffers target android build> export FLATBUFFERS_X86_BUILD=<path to flatbuffers host build-x86_64>
If the user only wishes to build the Support Library with the NDK, the Arm NN repo can be cloned into any folder. If the user also wishes to build the Arm NN Shim, for this the Arm NN repo will need to reside within the Android tree in order for armnn/shim/Android.bp to be picked up by the Soong (Android) build system. For example $AOSP_ROOT/vendor/arm/armnn
sudo apt install git
)cd $WORKING_DIR git clone https://github.com/ARM-software/armnn.git
Arm NN provides a script that downloads the version of Arm Compute Library that Arm NN was tested with:
${WORKING_DIR}/armnn/scripts/get_compute_library.sh
sudo apt install scons
)cd ${WORKING_DIR}/clframework scons arch=arm64-v8a \ toolchain_prefix=aarch64-linux-android- \ compiler_prefix=aarch64-linux-android29- \ neon=1 opencl=1 \ embed_kernels=1 \ build_dir=android-arm64v8a \ extra_cxx_flags="-Wno-parentheses-equality -Wno-missing-braces -fPIC" \ Werror=0 embed_kernels=1 examples=0 \ validation_tests=0 benchmark_tests=0 benchmark_examples=0 os=android -j16
sudo apt install cmake
)cd $ARMNN_BUILD_DIR CXX=aarch64-linux-android29-clang++ \ CC=aarch64-linux-android29-clang \ CXX_FLAGS="-fPIE -fPIC" cmake ${WORKING_DIR}/armnn \ -DCMAKE_ANDROID_NDK=$NDK \ -DCMAKE_SYSTEM_NAME=Android \ -DCMAKE_SYSTEM_VERSION=29 \ -DCMAKE_ANDROID_ARCH_ABI=arm64-v8a \ -DCMAKE_EXE_LINKER_FLAGS="-pie -llog -lz" \ -DARMCOMPUTE_ROOT=$WORKING_DIR/clframework/ \ -DARMCOMPUTE_BUILD_DIR=$WORKING_DIR/clframework/build/android-arm64v8a/ \ -DARMCOMPUTENEON=1 -DARMCOMPUTECL=1 -DARMNNREF=1 \ -DFLATBUFFERS_ROOT=$FLATBUFFERS_ANDROID_BUILD \ -DFLATC_DIR=$FLATBUFFERS_X86_BUILD \ -DBUILD_ARMNN_SERIALIZER=1 -DBUILD_GATORD_MOCK=0 -DBUILD_BASE_PIPE_SERVER=0
make -j16
Building the support library requires building some AOSP libraries via the NDK. It should be possible to use $AOSP_ROOT instead of $AOSP_MODULES_ROOT.
However this example will instead clone the necessary AOSP repos outside of the Android tree and apply some minor patches which were required to get it to build with the Android version used in this guide.
# Call a script which will clone the necessary AOSP repos (do not clone them into Android tree) ${WORKING_DIR}/armnn/shim/sl/scripts/clone_aosp_libs.sh $AOSP_MODULES_ROOT # Modify the repos by applying patches ${WORKING_DIR}/armnn/shim/sl/scripts/modify_aosp_libs.sh $AOSP_MODULES_ROOT # Build the Support Library CMARGS="$CMARGS \ -DCMAKE_TOOLCHAIN_FILE=$NDK/build/cmake/android.toolchain.cmake \ -DANDROID_ABI=arm64-v8a \ -DCMAKE_ANDROID_ARCH_ABI=arm64-v8a \ -DCMAKE_ANDROID_NDK=$NDK \ -DANDROID_PLATFORM=android-29 \ -DAOSP_MODULES_ROOT=$AOSP_MODULES_ROOT \ -DARMNN_SOURCE_DIR=$WORKING_DIR/armnn \ -DArmnn_DIR=$ARMNN_BUILD_DIR " mkdir ${WORKING_DIR}/armnn/shim/sl/build cd ${WORKING_DIR}/armnn/shim/sl/build CXX=aarch64-linux-android29-clang++ \ CC=aarch64-linux-android29-clang \ cmake $CMARGS ../ make
By default the Arm NN shim Android.bp.off is not enabled. It is enabled below by renaming it to Android.bp
cd ${WORKING_DIR}/armnn/shim mv Android.bp.off Android.bp cd $AOSP_ROOT source build/envsetup.sh lunch <device>-eng cd vendor/arm/armnn/shim export ARMNN_ANDROID_MK_ENABLE=0 mm
The built libraries and manifest file can be found here: $AOSP_ROOT/out/target/product//vendor/lib64/libarmnn_support_library.so $AOSP_ROOT/out/target/product//vendor/bin/hw/android.hardware.neuralnetworks-shim-service-armnn $AOSP_ROOT/out/target/product//vendor/etc/vintf/manifest/android.hardware.neuralnetworks-shim-service-armnn.xml
Currently the Arm NN libraries are shared libraries and therefore will need to be pushed to the device: $ARMNN_BUILD_DIR/libarmnn.so