diff --git a/.github/workflows/build_cxx_sysroot.yml b/.github/workflows/build_cxx_sysroot.yml
index b8f0074cd..9f309c999 100644
--- a/.github/workflows/build_cxx_sysroot.yml
+++ b/.github/workflows/build_cxx_sysroot.yml
@@ -26,7 +26,7 @@ jobs:
         uses: actions/checkout@v3
         with:
           submodules: true
-      
+
       - name: Build
         run: |
           git config --global --add safe.directory $(pwd)
@@ -35,79 +35,6 @@ jobs:
           cp -r sysroot /opt/wasix-sysroot
           cp .github/workflows/files/clang-wasix.cmake_toolchain /opt/wasix-sysroot/clang-wasix.cmake_toolchain
 
-      - name: Determine LLVM revision
-        run: |
-          export LLVM_TAG=$(echo "llvmorg-$(llvm-ar --version | grep -i "LLVM version" | sed -r 's/.*version ([0-9\.]+).*/\1/')")
-          echo "LLVM tag: $LLVM_TAG"
-          echo "LLVM_REV=$(git ls-remote --tags https://github.com/llvm/llvm-project.git $LLVM_TAG | sed -r 's/([^ \t]*).*/\1/')" | tee -a $GITHUB_ENV
-          echo "LLVM_TAG=$LLVM_TAG" | tee -a $GITHUB_ENV
-        
-      - name: Cache LLVM
-        uses: actions/cache@v3
-        if: ${{ !env.ACT }}
-        with:
-          path: llvm-project
-          key: llvm-${{ env.LLVM_REV }}
-        
-      - name: Checkout LLVM
-        run: |
-          if [ ! -d "llvm-project" ]; then git clone https://github.com/llvm/llvm-project.git; fi
-          cd llvm-project
-          git fetch origin refs/tags/${{ env.LLVM_TAG }}
-          if [ "$(git rev-parse ${{ env.LLVM_TAG }})" != "$(git rev-parse HEAD)" ]; then echo "Checkout ($(git rev-parse ${{ env.LLVM_TAG }}) != $(git rev-parse HEAD))" && git reset --hard ${{ env.LLVM_TAG }} && echo "checked out $(git rev-parse HEAD)"; fi
-      
-      - name: Build and install compiler_rt builtins
-        run: |
-          mkdir -p build-compiler-rt-builtins
-          cd build-compiler-rt-builtins
-          cmake --fresh -DCOMPILER_RT_BAREMETAL_BUILD=On -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCOMPILER_RT_OS_DIR=wasm32-wasi -DCOMPILER_RT_DEFAULT_TARGET_ONLY:BOOL=ON -DCMAKE_TOOLCHAIN_FILE=/opt/wasix-sysroot/clang-wasix.cmake_toolchain -DCMAKE_SYSROOT=/opt/wasix-sysroot -DCMAKE_INSTALL_PREFIX=/opt/wasix-sysroot ../llvm-project/compiler-rt/lib/builtins
-          cmake --build . --target install --parallel 4
-          export CLANG_MAJOR_VERSION=$(clang --version | grep -i "clang version" | sed -r 's/.*version ([0-9]+).*/\1/')
-          mkdir -p /usr/lib/clang/$CLANG_MAJOR_VERSION/lib/wasi
-          cp /opt/wasix-sysroot/lib/wasm32-wasi/libclang_rt.builtins-wasm32.a /usr/lib/clang/$CLANG_MAJOR_VERSION/lib/wasi/libclang_rt.builtins-wasm32.a
-
-      - name: Build and install LLVM libc++
-        run: >
-          mkdir -p build-libcxx &&
-          cd build-libcxx &&
-          cmake
-          --fresh
-          -DCMAKE_TOOLCHAIN_FILE=/opt/wasix-sysroot/clang-wasix.cmake_toolchain
-          -DCMAKE_SYSROOT=/opt/wasix-sysroot
-          -DCMAKE_INSTALL_PREFIX=/opt/wasix-sysroot
-          -DCXX_SUPPORTS_CXX23=ON
-          -DLIBCXX_ENABLE_THREADS:BOOL=ON
-          -DLIBCXX_HAS_PTHREAD_API:BOOL=ON
-          -DLIBCXX_HAS_EXTERNAL_THREAD_API:BOOL=OFF
-          -DLIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY:BOOL=OFF
-          -DLIBCXX_HAS_WIN32_THREAD_API:BOOL=OFF
-          -DCMAKE_BUILD_TYPE=RelWithDebugInfo
-          -DLIBCXX_ENABLE_SHARED:BOOL=OFF
-          -DLIBCXX_ENABLE_EXPERIMENTAL_LIBRARY:BOOL=OFF
-          -DLIBCXX_ENABLE_EXCEPTIONS:BOOL=OFF
-          -DLIBCXX_ENABLE_FILESYSTEM:BOOL=OFF
-          -DLIBCXX_CXX_ABI=libcxxabi
-          -DLIBCXX_HAS_MUSL_LIBC:BOOL=ON
-          -DLIBCXX_ABI_VERSION=2
-          -DLIBCXXABI_ENABLE_EXCEPTIONS:BOOL=OFF
-          -DLIBCXXABI_ENABLE_SHARED:BOOL=OFF
-          -DLIBCXXABI_SILENT_TERMINATE:BOOL=ON
-          -DLIBCXXABI_ENABLE_THREADS:BOOL=ON
-          -DLIBCXXABI_HAS_PTHREAD_API:BOOL=ON
-          -DLIBCXXABI_HAS_EXTERNAL_THREAD_API:BOOL=OFF
-          -DLIBCXXABI_BUILD_EXTERNAL_THREAD_LIBRARY:BOOL=OFF
-          -DLIBCXXABI_HAS_WIN32_THREAD_API:BOOL=OFF
-          -DLIBCXXABI_ENABLE_PIC:BOOL=OFF
-          -DCMAKE_C_COMPILER_WORKS=ON
-          -DCMAKE_CXX_COMPILER_WORKS=ON
-          -DLLVM_COMPILER_CHECKED=ON
-          -DUNIX:BOOL=ON
-          -DLIBCXX_LIBDIR_SUFFIX=/wasm32-wasi
-          -DLIBCXXABI_LIBDIR_SUFFIX=/wasm32-wasi
-          -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi"
-          ../llvm-project/runtimes
-          && cmake --build . --target install --parallel 4
-
       - name: Upload sysroot
         if: ${{ !env.ACT }}
         uses: actions/upload-artifact@v2
diff --git a/.gitmodules b/.gitmodules
index c116f3c6d..5a3918136 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -4,3 +4,6 @@
 [submodule "tools/wasix-headers/WASI"]
 	path = tools/wasix-headers/WASI
 	url = https://github.com/wasix-org/wasix-witx.git
+[submodule "tools/llvm-project"]
+	path = tools/llvm-project
+	url = https://github.com/llvm/llvm-project.git
diff --git a/build32.sh b/build32.sh
index c83af6214..421cbdb57 100755
--- a/build32.sh
+++ b/build32.sh
@@ -29,4 +29,46 @@ EOF
 
 make -j 14
 rm -f sysroot/lib/wasm32-wasi/libc-printscan-long-double.a
+
+# Build C++ sysroot
+mkdir -p build/libcxx
+cd build/libcxx
+cmake \
+    -DCMAKE_TOOLCHAIN_FILE=$(pwd)/../../tools/clang-wasix.cmake_toolchain \
+    -DCMAKE_SYSROOT=$(pwd)/../../sysroot \
+    -DCMAKE_INSTALL_PREFIX=$(pwd)/../../sysroot \
+    -DCXX_SUPPORTS_CXX23=ON \
+    -DLIBCXX_ENABLE_THREADS:BOOL=ON \
+    -DLIBCXX_HAS_PTHREAD_API:BOOL=ON \
+    -DLIBCXX_HAS_EXTERNAL_THREAD_API:BOOL=OFF \
+    -DLIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY:BOOL=OFF \
+    -DLIBCXX_HAS_WIN32_THREAD_API:BOOL=OFF \
+    -DCMAKE_BUILD_TYPE=RelWithDebugInfo \
+    -DLIBCXX_ENABLE_SHARED:BOOL=OFF \
+    -DLIBCXX_ENABLE_EXPERIMENTAL_LIBRARY:BOOL=OFF \
+    -DLIBCXX_ENABLE_EXCEPTIONS:BOOL=OFF \
+    -DLIBCXX_ENABLE_FILESYSTEM:BOOL=OFF \
+    -DLIBCXX_CXX_ABI=libcxxabi \
+    -DLIBCXX_HAS_MUSL_LIBC:BOOL=ON \
+    -DLIBCXX_ABI_VERSION=2 \
+    -DLIBCXXABI_ENABLE_EXCEPTIONS:BOOL=OFF \
+    -DLIBCXXABI_ENABLE_SHARED:BOOL=OFF \
+    -DLIBCXXABI_SILENT_TERMINATE:BOOL=ON \
+    -DLIBCXXABI_ENABLE_THREADS:BOOL=ON \
+    -DLIBCXXABI_HAS_PTHREAD_API:BOOL=ON \
+    -DLIBCXXABI_HAS_EXTERNAL_THREAD_API:BOOL=OFF \
+    -DLIBCXXABI_BUILD_EXTERNAL_THREAD_LIBRARY:BOOL=OFF \
+    -DLIBCXXABI_HAS_WIN32_THREAD_API:BOOL=OFF \
+    -DLIBCXXABI_ENABLE_PIC:BOOL=OFF \
+    -DCMAKE_C_COMPILER_WORKS=ON \
+    -DCMAKE_CXX_COMPILER_WORKS=ON \
+    -DLLVM_COMPILER_CHECKED=ON \
+    -DUNIX:BOOL=ON \
+    -DLIBCXX_LIBDIR_SUFFIX=/wasm32-wasi \
+    -DLIBCXXABI_LIBDIR_SUFFIX=/wasm32-wasi \
+    -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi" \
+    ../../tools/llvm-project/runtimes
+cmake --build . --target install --parallel 14
+cd ../..
+
 rsync -Lrtv --delete ./sysroot/ ./sysroot32/
diff --git a/.github/workflows/files/clang-wasix.cmake_toolchain b/tools/clang-wasix.cmake_toolchain
similarity index 100%
rename from .github/workflows/files/clang-wasix.cmake_toolchain
rename to tools/clang-wasix.cmake_toolchain