precompile_llvm.sh

#!/bin/bash
set -Eeuo pipefail
SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
cd $SCRIPT_DIR

keep_build=true
force_override=false
full_rerun=false
while [ $# -gt 0 ]; do
    if  [ "$1" = "-c" ] || [ "$1" = "--cleanup" ]; then
        keep_build=false
        shift
    elif  [ "$1" = "-f" ] || [ "$1" = "--force" ]; then
        force_override=true
        shift
    elif  [ "$1" = "-r" ] || [ "$1" = "--full" ]; then
        full_rerun=true
        shift
    else
        echo "unkwnown option $1" >&2
        exit -1
    fi
done

# make sure llvm is up to date
git submodule update --init --recursive

#if this dir exist we already precompiled
cd ./deps/llvm-project/
if [ -d "../llvm-project-prebuild" ]; then
    #if we have the same commit id as during the prebuild exit successfully
    if ! $force_override && [ "$(git rev-parse HEAD)" == "$(cat ../llvm-project-prebuild/prebuild_commit_id.txt 2>/dev/null || : )" ]; then
        echo "found existing prebuild"
        exit 0
    fi
    rm -rf ../llvm-project-prebuild
    if $full_rerun; then
        rm -rf ../../precomile_llvm
    fi
fi
cd ../../

# compile tauc with llvm as a non precompiled dependency in ./precompile_llvm
mkdir -p ./precompile_llvm
cd ./precompile_llvm
cmake -DCMAKE_BUILD_TYPE=Release -DTAU_COMPILE_LLVM:BOOL=ON ../
make -j$(nproc) || :
cd ..

# move the resulting llvm libs to ./deps/llvm-project-prebuild and delete the rest
src="./precompile_llvm/deps/llvm-project/llvm/"
dest="./deps/llvm-project-prebuild"
mkdir -p "$dest" "$dest/lib"
if $keep_build; then
    cmd="cp -r"
else
    cmd="mv"
fi
mkdir -p $src/lib
$cmd "$src/lib/"*.a "$dest/lib/"
$cmd "$src/bin" "$dest/bin"
$cmd "$src/include" "$dest/include"


#store the llvm commit id
cd ./deps/llvm-project
git rev-parse HEAD > ../llvm-project-prebuild/prebuild_commit_id.txt
cd ../../

# create empty files for the libs we don't need to stop llvm-config from complaining
# we later check for these during linking and ignore them
#since we are using the error output here we expect to get an error so we ignore the status code
(./deps/llvm-project-prebuild/bin/llvm-config --libs 2>&1 1>/dev/null || : ) | sed -n "s/.*error: missing: //p" | xargs -r touch || : 
# done
exit 0