name: Set up LLVM on macOS
description: Restore or build LLVM

inputs:
  os:
    description: Runner image name, used in the cache key
    required: true
  save-cache:
    description: Save LLVM caches after a cache miss
    required: false
    default: "true"

runs:
  using: composite
  steps:
    - name: Restore LLVM source cache
      uses: actions/cache/restore@v5
      id: cache-llvm-source
      with:
        key: llvm-source-22-${{ inputs.os }}-v1-${{ hashFiles('llvm-version.txt') }}
        path: |
          llvm-project/clang/lib/Headers
          llvm-project/clang/include
          llvm-project/compiler-rt
          llvm-project/lld/include
          llvm-project/llvm/include
    - name: Download LLVM source
      if: steps.cache-llvm-source.outputs.cache-hit != 'true'
      shell: bash
      run: make llvm-source
    - name: Save LLVM source cache
      uses: actions/cache/save@v5
      if: inputs.save-cache == 'true' && steps.cache-llvm-source.outputs.cache-hit != 'true'
      with:
        key: ${{ steps.cache-llvm-source.outputs.cache-primary-key }}
        path: |
          llvm-project/clang/lib/Headers
          llvm-project/clang/include
          llvm-project/compiler-rt
          llvm-project/lld/include
          llvm-project/llvm/include
    - name: Restore LLVM build cache
      uses: actions/cache/restore@v5
      id: cache-llvm-build
      with:
        key: llvm-build-22-${{ inputs.os }}-v1-${{ hashFiles('llvm-version.txt') }}
        path: llvm-build
    - name: Build LLVM
      if: steps.cache-llvm-build.outputs.cache-hit != 'true'
      shell: bash
      run: |
        # fetch LLVM source
        rm -rf llvm-project
        make llvm-source
        # install dependencies
        HOMEBREW_NO_AUTO_UPDATE=1 brew install ninja
        # build!
        make llvm-build
        find llvm-build -name CMakeFiles -prune -exec rm -r '{}' \;
    - name: Save LLVM build cache
      uses: actions/cache/save@v5
      if: inputs.save-cache == 'true' && steps.cache-llvm-build.outputs.cache-hit != 'true'
      with:
        key: ${{ steps.cache-llvm-build.outputs.cache-primary-key }}
        path: llvm-build