Builder script for Clang/LLVM10 compiler for Nvidia Jetson Nano (could be extended to other Jetson boards) with OpenMP 4.5 offloading support. The script is created to be executed directly in the Nvidia Jetson Nano. Larger SWAP memory is required or I recommend you to build the compiler using an AArch64 emulator (see below).
(RECOMENDED) Build inside an AArch64 Docker container to emulate the Jetson systems: https://www.stereolabs.com/docs/docker/building-arm-container-on-x86/
sudo apt-get install qemu binfmt-support qemu-user-static docker run --name jetson --privileged --rm -it nvcr.io/nvidia/l4t-base:r32.2.1
Nvidia Jetson Nano has 4 GB of DDR4 memory, plus, by default, it has 2GB of SWAP. Memory usage during the build of Clang/LLVM may be larger, thus is recommended to increase the SWAP partition to 8-16GB. You can do it following this tutorial: https://www.jetsonhacks.com/2019/11/28/jetson-nano-even-more-swap/
- Clang/LLVM v10.0.0
- Supported Compute Capabilities:
53,62,72 - Default
CLANG_OPENMP_NVPTX_DEFAULT_ARCHissm_53(Compute Capability 5.3)
You can extend the Compute Capabilities setting the CLANG_OPENMP_NVPTX_DEFAULT_ARCH and LIBOMPTARGET_NVPTX_COMPUTE_CAPABILITIES environmental variables.
- Build Clang/LLVM
./jetson-llvm-builder [-s $LLVM_SRC] [-i $LLVM_PATH]
The script will download the required Clang/LLVM sources in the $LLVM_SRC (default: /$HOME). The default value for $LLVM_PATH is /usr/local/.
- Use the new compiler Following environment variables need to be set before using Clang/LLVM
export PATH=$LLVM_PATH:$PATH
export LD_LIBRARY_PATH=$LLVM_PATH/libexec:$LD_LIBRARY_PATH
export LD_LIBRARY_PATH=$LLVM_PATH/lib:$LD_LIBRARY_PATH
export LIBRARY_PATH=$LLVM_PATH/libexec:$LIBRARY_PATH
export LIBRARY_PATH=$LLVM_PATH/lib:$LIBRARY_PATH
export MANPATH=$LLVM_PATH/share/man:$MANPATH
export C_INCLUDE_PATH=$LLVM_PATH/include:$C_INCLUDE_PATH
export CPLUS_INCLUDE_PATH=$LLVM_PATH/include:CPLUS_INCLUDE_PATH