#!/bin/bash

set -euxo pipefail

LLVM_VERSION="${LLVM_VERSION:-21}"
MSAN_PREFIX="${MSAN_PREFIX:-$PWD/msan}"
JOBS="${JOBS:-$(nproc)}"

cd /tmp
rm -rf libcxx-msan
mkdir libcxx-msan
cd libcxx-msan

git clone --depth=1 "https://github.com/llvm/llvm-project.git" -b "release/${LLVM_VERSION}.x"

cmake -S llvm-project/runtimes -B build \
  -DCMAKE_BUILD_TYPE=Release \
  -DCMAKE_C_COMPILER="clang-${LLVM_VERSION}" \
  -DCMAKE_CXX_COMPILER="clang++-${LLVM_VERSION}" \
  -DLLVM_USE_SANITIZER=MemoryWithOrigins \
  -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi;libunwind" \
  -DLLVM_TARGETS_TO_BUILD=Native \
  -DCMAKE_INSTALL_PREFIX="${MSAN_PREFIX}" \
  -DLIBCXXABI_USE_LLVM_UNWINDER=ON \
  -DLIBCXXABI_ENABLE_STATIC_UNWINDER=ON \
  -DLIBCXX_USE_COMPILER_RT=ON \
  -DLIBCXXABI_USE_COMPILER_RT=ON \
  -DLIBUNWIND_USE_COMPILER_RT=ON \
  -DLIBCXX_INCLUDE_TESTS=OFF \
  -DLIBCXXABI_INCLUDE_TESTS=OFF \
  -DLIBUNWIND_INCLUDE_TESTS=OFF \
  -DLIBCXX_ENABLE_CLANG_TIDY=OFF

cmake --build build -j"${JOBS}"
cmake --install build

VERSION="$(clang-"${LLVM_VERSION}" --version | head -n1 | sed -E 's/.*clang version ([0-9.]+).*/\1/')"
TARBALL="msan-toolchain-${VERSION}.tar.zst"

tar --zstd -cf "${TARBALL}" -C "${MSAN_PREFIX}" .

TARBALL_PATH="$(pwd)/${TARBALL}"
echo "Created: ${TARBALL_PATH}"