[Support] Add MacOS as a host for ELD

.github/workflows/CheckNonDocChanges/action.yaml

@@ -0,0 +1,68 @@
+name: Check for non-doc changes
+description: >
+  Compare the ELD checkout to qualcomm/eld's PR base and set skip_build when
+  the PR only touches docs/. Shared by ci.yml, ci-macos.yml, and ci-win.yml.
+
+inputs:
+  base-branch:
+    description: "Base branch on qualcomm/eld (e.g. main)"
+    required: true
+  base-sha:
+    description: "github.event.pull_request.base.sha — the base commit GitHub already resolved"
+    required: true
+  eld-root:
+    description: >
+      ELD checkout root (the directory that contains .git). Required when this
+      action is staged away from <eld>/.github/workflows/CheckNonDocChanges,
+      because uses: cannot interpolate github/env into a local path.
+    required: false
+    default: ''
+
+outputs:
+  skip_build:
+    description: "true if only docs changed; false otherwise"
+    value: ${{ steps.file-check.outputs.skip_build }}
+
+runs:
+  using: composite
+  steps:
+    - name: Check for non-doc changes
+      id: file-check
+      shell: bash
+      env:
+        BASE_BRANCH_NAME: ${{ inputs.base-branch }}
+        BASE_SHA: ${{ inputs.base-sha }}
+      # Default: action lives at <eld>/.github/workflows/CheckNonDocChanges.
+      # ci.yml stages a copy at the workspace root, so it passes eld-root.
+      working-directory: ${{ inputs.eld-root || format('{0}/../../..', github.action_path) }}
+      run: |
+        set -euo pipefail
+        # We need the base commit from qualcomm/eld, not from the fork.
+        git remote add QC https://github.com/qualcomm/eld.git
+        # Prefer the event SHA (one commit, no history walk). Fall back to the
+        # branch tip if the remote will not serve a raw SHA.
+        git fetch --no-tags --depth=1 QC "${BASE_SHA}" || \
+          git fetch --no-tags --depth=1 QC "${BASE_BRANCH_NAME}"
+        if git cat-file -e "${BASE_SHA}^{commit}" 2>/dev/null; then
+          BASE="${BASE_SHA}"
+        elif git rev-parse --verify "QC/${BASE_BRANCH_NAME}^{commit}" >/dev/null 2>&1; then
+          BASE="QC/${BASE_BRANCH_NAME}"
+        else
+          echo "::error::Could not resolve base ${BASE_SHA} or QC/${BASE_BRANCH_NAME}"
+          git rev-parse HEAD
+          git remote -v
+          exit 1
+        fi
+        # Two-dot tree diff: both objects exist after the fetch, so this does
+        # not need merge-base (which fails on a depth-1 QC/main vs a fork HEAD).
+        CHANGED_FILES=$(git diff --name-only "${BASE}" HEAD)
+        echo "diff-base: ${BASE}"
+        echo "Changed files: ${CHANGED_FILES}"
+        for file in $CHANGED_FILES; do
+          if [[ ! "$file" =~ ^docs/ && ! "$file" =~ \.md$ ]]; then
+            echo "skip_build=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+        done
+        echo "Only docs changed. Skipping build."
+        echo "skip_build=true" >> "$GITHUB_OUTPUT"

.github/workflows/ci-macos.yml

@@ -0,0 +1,169 @@
+name: macOS CI
+
+# GitHub-hosted Darwin host build of ld.eld (ELF linker, not a Mach-O target).
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened]
+    paths-ignore:
+      - '.github/workflows/sanitize.yml'
+      - '.github/workflows/reviter.yml'
+      - '.github/workflows/docs.yaml'
+      - '.github/workflows/docs-multiversion.yaml'
+      - '.github/workflows/ci.yml'
+      - '.github/workflows/ci-win.yml'
+      - '.github/workflows/clang-cross-schedule.yml'
+      - '.github/workflows/DownloadClangCrossToolchain/action.yaml'
+      - '.github/workflows/DownloadLatestBusybox/action.yaml'
+      - '.github/workflows/busybox.yml'
+      - '.github/workflows/linux-kernel-nightly.yml'
+      - '.github/workflows/linux-kernel-run.yml'
+      - '.github/workflows/linux-kernel-pr.yml'
+      - '.github/workflows/nightly-musl-builder.yml'
+      - '.github/workflows/picolibc-builder.yml'
+      - '.github/workflows/nightly-test.yml'
+      - '.github/workflows/update-build-dashboard-data.yml'
+      - '.github/workflows/scripts/record_builds.py'
+      - '.github/workflows/BuildStatusDataRecorder/action.yaml'
+      - '.github/workflows/clang-format-pr.yml'
+      - '.github/workflows/cpp-linter-pr.yml'
+      - 'etc/**/*.sh'
+  workflow_dispatch: {}
+
+permissions:
+  contents: read
+
+jobs:
+  build-macos:
+    name: macOS
+    runs-on: macos-latest
+    timeout-minutes: 180
+    concurrency:
+      group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
+      cancel-in-progress: true
+    env:
+      BASE_BRANCH_NAME: ${{ github.event.pull_request.base.ref || 'main' }}
+      ELD_REPO: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name || github.repository }}
+      ELD_REF: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.ref || github.ref_name }}
+      CCACHE_DIR: ${{ github.workspace }}/obj/ccache
+      CCACHE_BASEDIR: ${{ github.workspace }}
+      CCACHE_COMPILERCHECK: content
+      CCACHE_NOHASHDIR: true
+
+    steps:
+      - name: Set up Python
+        uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 #v7.0.0
+        with:
+          python-version: '3.14'
+
+      - name: Install build tools
+        env:
+          HOMEBREW_NO_AUTO_UPDATE: 1
+          HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK: 1
+        run: |
+          command -v ninja >/dev/null || brew install ninja
+          command -v ccache >/dev/null || brew install ccache
+          python3 -m pip install pyyaml
+          echo "cmake $(cmake --version | head -n1)"
+          echo "ninja $(ninja --version)"
+          echo "ccache $(ccache --version | head -n1)"
+          echo "clang $(clang --version | head -n1)"
+          echo "python $(python3 --version) from $(which python3)"
+          sysctl hw.ncpu hw.physicalcpu hw.memsize || true
+          df -h .
+
+      - name: Checkout llvm-project
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          repository: llvm/llvm-project
+          ref: ${{ env.BASE_BRANCH_NAME }}
+          path: llvm-project
+          fetch-depth: 1
+
+      - name: Checkout ELD
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          repository: ${{ env.ELD_REPO }}
+          ref: ${{ env.ELD_REF }}
+          path: llvm-project/llvm/tools/eld
+          fetch-depth: 0
+
+      - name: Check for non-doc changes
+        id: file-check
+        if: github.event_name == 'pull_request'
+        uses: ./llvm-project/llvm/tools/eld/.github/workflows/CheckNonDocChanges
+        with:
+          base-branch: ${{ env.BASE_BRANCH_NAME }}
+          base-sha: ${{ github.event.pull_request.base.sha }}
+
+      - name: Restore ccache
+        if: github.event_name != 'pull_request' || steps.file-check.outputs.skip_build == 'false'
+        uses: actions/cache/restore@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 #v6.1.0
+        with:
+          path: ${{ github.workspace }}/obj/ccache
+          key: macos-eld-ccache-${{ runner.arch }}-${{ github.run_id }}
+          restore-keys: |
+            macos-eld-ccache-${{ runner.arch }}-
+
+      - name: Configure CMake
+        if: github.event_name != 'pull_request' || steps.file-check.outputs.skip_build == 'false'
+        working-directory: ${{ github.workspace }}
+        run: |
+          set -euo pipefail
+          test -f llvm-project/cmake/Modules/CMakePolicy.cmake
+          test -d llvm-project/clang
+          test -d llvm-project/third-party/unittest
+          test -d llvm-project/llvm/tools/eld
+          mkdir -p "$CCACHE_DIR" obj
+          ccache --zero-stats || true
+          cmake -G Ninja -S llvm-project/llvm -B obj \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DCMAKE_DISABLE_PRECOMPILE_HEADERS=ON \
+            -DLLVM_ENABLE_PROJECTS="clang" \
+            -DLLVM_ENABLE_ASSERTIONS:BOOL=ON \
+            -DLLVM_ENABLE_LLD:BOOL=OFF \
+            -DLLVM_TARGETS_TO_BUILD="ARM;AArch64;RISCV;Hexagon;X86" \
+            -DELD_TARGETS_TO_BUILD='ARM;AArch64;RISCV;Hexagon;X86;Template' \
+            -DCMAKE_C_COMPILER="$(xcrun --find clang)" \
+            -DCMAKE_CXX_COMPILER="$(xcrun --find clang++)" \
+            -DCMAKE_CXX_FLAGS="-stdlib=libc++" \
+            -DLLVM_PARALLEL_LINK_JOBS=1 \
+            -DLLVM_CCACHE_BUILD:BOOL=ON \
+            -DLLVM_CCACHE_DIR:STRING="$CCACHE_DIR" \
+            -DELD_ENABLE_SYMBOL_VERSIONING=ON
+
+      - name: Build
+        if: github.event_name != 'pull_request' || steps.file-check.outputs.skip_build == 'false'
+        working-directory: ${{ github.workspace }}/obj
+        # Full tree so lit finds opt and other LLVM tools. `ninja ld.eld clang`
+        # leaves those missing, and the set of tools tests need can grow.
+        run: ninja
+
+      - name: Cache usage after build
+        if: github.event_name != 'pull_request' || steps.file-check.outputs.skip_build == 'false'
+        run: ccache --show-stats --dir="$CCACHE_DIR" || true
+
+      - name: Run tests
+        if: github.event_name != 'pull_request' || steps.file-check.outputs.skip_build == 'false'
+        working-directory: ${{ github.workspace }}/obj
+        run: ninja check-eld
+
+      - name: Summarize test results
+        if: github.event_name != 'pull_request' || steps.file-check.outputs.skip_build == 'false'
+        working-directory: ${{ github.workspace }}/obj
+        run: ninja check-eld-summary
+
+      - name: Prune ccache before save
+        if: always() && (github.event_name != 'pull_request' || steps.file-check.outputs.skip_build == 'false')
+        run: ccache --evict-older-than 7200s --dir="$CCACHE_DIR" || true
+
+      - name: Save ccache
+        if: always() && (github.event_name != 'pull_request' || steps.file-check.outputs.skip_build == 'false')
+        uses: actions/cache/save@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 #v6.1.0
+        with:
+          path: ${{ github.workspace }}/obj/ccache
+          key: macos-eld-ccache-${{ runner.arch }}-${{ github.run_id }}
+
+      - name: Clean up
+        if: always()
+        run: rm -rf llvm-project obj

.github/workflows/ci-win.yml

@@ -65,6 +65,14 @@ jobs:
           path: nightly/llvm-project/llvm/tools/eld
           fetch-depth: 0
 
+      - name: Check for non-doc changes
+        id: file-check
+        if: github.event_name == 'pull_request'
+        uses: ./nightly/llvm-project/llvm/tools/eld/.github/workflows/CheckNonDocChanges
+        with:
+          base-branch: ${{ env.BASE_BRANCH_NAME }}
+          base-sha: ${{ github.event.pull_request.base.sha }}
+
       - name: Record pre-build entry
         if: github.event_name == 'schedule'
         uses: ./nightly/llvm-project/llvm/tools/eld/.github/workflows/BuildStatusDataRecorder
@@ -80,6 +88,7 @@ jobs:
           branch-name: "${{ env.ELD_REF }}"
 
       - name: Configure CMake
+        if: github.event_name != 'pull_request' || steps.file-check.outputs.skip_build == 'false'
         working-directory: nightly
         shell: bash
         run: |
@@ -95,22 +104,26 @@ jobs:
             ../llvm-project/llvm
 
       - name: Build
+        if: github.event_name != 'pull_request' || steps.file-check.outputs.skip_build == 'false'
         working-directory: nightly/obj
         shell: bash
         run: cmake --build . --config Release
 
       - name: Install PyYAML
+        if: github.event_name != 'pull_request' || steps.file-check.outputs.skip_build == 'false'
         shell: bash
         run: |
           echo "Installing dependencies using $(python --version) at $(which python)"
           python -m pip install pyyaml psutil
 
       - name: Run tests
+        if: github.event_name != 'pull_request' || steps.file-check.outputs.skip_build == 'false'
         working-directory: nightly/obj
         shell: bash
         run: cmake --build . --config Release --target check-eld
 
       - name: Summarize test results
+        if: github.event_name != 'pull_request' || steps.file-check.outputs.skip_build == 'false'
         working-directory: nightly/obj
         shell: bash
         run: cmake --build . --config Release --target check-eld-summary

.github/workflows/ci.yml

@@ -11,6 +11,7 @@ on:
       - '.github/workflows/docs.yaml'
       - '.github/workflows/docs-multiversion.yaml'
       - '.github/workflows/ci-win.yml'
+      - '.github/workflows/ci-macos.yml'
       - '.github/workflows/clang-cross-schedule.yml'
       - '.github/workflows/DownloadClangCrossToolchain/action.yaml'
       - '.github/workflows/DownloadLatestBusybox/action.yaml'
@@ -74,24 +75,20 @@ jobs:
       - name: Setup musl environment
         run: echo "/opt/musl/bin" >> $GITHUB_PATH
 
+      # uses: cannot contain ${{ github.* }} or ${{ env.* }}; stage a static path.
+      - name: Stage CheckNonDocChanges
+        run: |
+          rm -rf CheckNonDocChanges
+          cp -R "pr-${PR_NUMBER}/llvm-project/llvm/tools/eld/.github/workflows/CheckNonDocChanges" \
+            CheckNonDocChanges
+
       - name: Check for non-doc changes
         id: file-check
-        working-directory: pr-${{ env.PR_NUMBER }}/llvm-project/llvm/tools/eld
-        run: |
-          # We need to use base branch from qualcomm/eld
-          git remote add QC https://github.com/qualcomm/eld.git
-          git fetch QC ${{ env.BASE_BRANCH_NAME }} --depth=1
-          MERGE_BASE=$(git merge-base QC/${{ env.BASE_BRANCH_NAME }} HEAD)
-          CHANGED_FILES=$(git diff --name-only "$MERGE_BASE" HEAD)
-          echo "Changed files: $CHANGED_FILES"
-          for file in $CHANGED_FILES; do
-            if [[ ! "$file" =~ ^docs/ && ! "$file" =~ \.md$ ]]; then
-              echo "skip_build=false" >> "$GITHUB_OUTPUT"
-              exit 0
-            fi
-          done
-          echo "Only docs changed. Skipping build."
-          echo "skip_build=true" >> "$GITHUB_OUTPUT"
+        uses: ./CheckNonDocChanges
+        with:
+          base-branch: ${{ env.BASE_BRANCH_NAME }}
+          base-sha: ${{ github.event.pull_request.base.sha }}
+          eld-root: ${{ github.workspace }}/pr-${{ env.PR_NUMBER }}/llvm-project/llvm/tools/eld
 
       - name: Run CMake
         if: steps.file-check.outputs.skip_build == 'false'
@@ -216,4 +213,4 @@ jobs:
       - name: Clean up
         if: always()
         run: |
-          rm -rf "pr-${PR_NUMBER}"
+          rm -rf "pr-${PR_NUMBER}" CheckNonDocChanges