llvm_on_riscv.mdwn

   1 # Compiling LLVM on RISC-V
   2
   3 By simply copying & pasting the following, absolutely verbatim with no
   4 changes, you can get a working clang from the head of the official llvm
   5 master branch. I've tested it on a completely virgin install of Ubuntu
   6 16.04 LTS server. It should work on other versions of Ubuntu and on
   7 other Debian-based distros. (If it doesn't then please let me know)
   8
   9 Note that you currently must use a soft float version of the rv32 compiler
  10 and libraries.
  11
  12 You can skip the gnu toolchain and/or qemu parts if you already have
  13 those.
  14
  15     # about 17 GB of disk space is needed
  16     # entire process takes (not including apt-get, which is about 90 seconds on AWS):
  17     #   87m10s on i7-8650U Intel NUC with 32 GB RAM (on 30 Mbps VDSL internet in NZ)
  18     #   20m40s on server with Xeon E5-2667v4 @3.20GHz (16 cores)
  19     #   17m30s on an AWS m5.12xlarge with fresh Ubuntu 16.04 AMI (ami-4e79ed36)
  20
  21     #harmless if things are already installed. Obviously you can't do it if
  22     #you're not an admin
  23     sudo apt-get update
  24     sudo apt-get -y dist-upgrade
  25     sudo apt-get -y install \
  26       binutils build-essential libtool texinfo \
  27       gzip zip unzip patchutils curl git \
  28       make cmake ninja-build automake bison flex gperf \
  29       grep sed gawk python bc \
  30       zlib1g-dev libexpat1-dev libmpc-dev \
  31       libglib2.0-dev libfdt-dev libpixman-1-dev
  32
  33     mkdir riscv
  34     cd riscv
  35     mkdir _install
  36     export PATH=`pwd`/_install/bin:$PATH
  37
  38     git clone --recursive https://github.com/riscv/riscv-gnu-toolchain
  39     pushd riscv-gnu-toolchain
  40     ./configure --prefix=`pwd`/../_install --with-arch=rv32gc --with-abi=ilp32
  41     make -j`nproc`
  42     popd
  43
  44     git clone https://github.com/riscv/riscv-qemu
  45     pushd riscv-qemu
  46     ./configure --prefix=`pwd`/../_install --target-list=riscv32-linux-user
  47     make -j`nproc` install
  48     popd
  49
  50     git clone https://github.com/llvm-project/llvm-project-20170507 llvm
  51     pushd llvm
  52     (cd llvm/tools; ln -s ../../clang .)
  53     mkdir _build
  54     cd _build
  55     cmake -G Ninja -DCMAKE_BUILD_TYPE="Release" \
  56       -DBUILD_SHARED_LIBS=True -DLLVM_USE_SPLIT_DWARF=True \
  57       -DLLVM_OPTIMIZED_TABLEGEN=True -DLLVM_BUILD_TESTS=False \
  58       -DDEFAULT_SYSROOT="../../_install/riscv32-unknown-elf" \
  59       -DGCC_INSTALL_PREFIX="../../_install" \
  60       -DLLVM_DEFAULT_TARGET_TRIPLE="riscv32-unknown-elf" \
  61       -DLLVM_TARGETS_TO_BUILD="" \
  62       -DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD="RISCV" \
  63       ../llvm
  64     cmake --build .
  65     alias clang-rv32="`pwd`/bin/clang -Xclang -iwithsysroot -Xclang /include \
  66       -ccc-gcc-name riscv32-unknown-elf-gcc \
  67       -target riscv32 -march=rv32imc"
  68     popd
  69
  70     cat >hello.c <<END
  71     #include <stdio.h>
  72
  73     int main(){
  74       printf("Hello RISCV!\n");
  75       return 0;
  76     }
  77     END
  78
  79     clang-rv32 -O1 hello.c -o hello
  80     qemu-riscv32 hello
  81