#!/bin/bash

set -e

LLVM_VERSION=${1:-18.1.6}

SCRIPT_DIR=$(cd "$(dirname "$BASH_SOURCE")" ; pwd)

pushd ${SCRIPT_DIR}/../..

UE_MODULE_LOCATION=`pwd`

LLVM_ROOT_LOCATION="$UE_MODULE_LOCATION/llvm-$LLVM_VERSION"
LLVM_SOURCE_LOCATION="$LLVM_ROOT_LOCATION/llvm/"
LLVM_BUILD_LOCATION="$LLVM_SOURCE_LOCATION/build/"
LLVM_INSTALL_LOCATION="$UE_MODULE_LOCATION/llvm/"

CORES=$(getconf _NPROCESSORS_ONLN)

rm -rf $LLVM_INSTALL_LOCATION
rm -rf $LLVM_BUILD_LOCATION
rm -rf $LLVM_ROOT_LOCATION

echo Cloning and building llvm $LLVM_VERSION...
git clone https://github.com/llvm/llvm-project.git --branch llvmorg-$LLVM_VERSION llvm-$LLVM_VERSION

mkdir -p $LLVM_BUILD_LOCATION

CMAKE_ARGS=(
    -DCMAKE_INSTALL_PREFIX="$LLVM_INSTALL_LOCATION"
    -DCMAKE_BUILD_TYPE=Release
    -DLLVM_ENABLE_PROJECTS=clang
    -DLLVM_ENABLE_DUMP=ON
    -DLLVM_ENABLE_ASSERTIONS=ON
    -DLLVM_INSTALL_UTILS=ON
    -DLLVM_TARGETS_TO_BUILD="AArch64;ARM;X86"
    -DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=WebAssembly
)

BUILD_LOCATION="$UE_MODULE_LOCATION/Intermediate"

rm -rf $BUILD_LOCATION
mkdir $BUILD_LOCATION
pushd $BUILD_LOCATION

echo Configuring build for llvm version $LLVM_VERSION...
cmake -G "Unix Makefiles" $LLVM_SOURCE_LOCATION "${CMAKE_ARGS[@]}"

echo Building llvm for Release...
cmake --build . --config Release --parallel ${CORES}

echo Installing llvm for Release...
cmake --install . --config Release

popd

popd

echo Done.