[workflow][test] add busybox workflow

.github/workflows/busybox-eld.yml

@@ -0,0 +1,234 @@
+name: BusyBox with ELD
+
+on:
+  workflow_dispatch:
+  # pull_request: {}
+  schedule:
+   - cron: "0 5 * * *"
+
+permissions:
+  contents: write
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  fetch-clang-cross-toolchain:
+    if: github.repository == 'qualcomm/eld'
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - arch: x86_64
+            toolchain_asset: x86_64-unknown-linux-musl.tar.xz
+            enabled: 1
+          - arch: riscv32
+            toolchain_asset: riscv32-unknown-linux-musl.tar.xz
+            enabled: 0
+          - arch: riscv64
+            toolchain_asset: riscv64-unknown-linux-musl.tar.xz
+            enabled: 0
+          - arch: arm
+            toolchain_asset: arm-unknown-linux-musleabi.tar.xz
+            enabled: 0
+          - arch: aarch64
+            toolchain_asset: aarch64-unknown-linux-musl.tar.xz
+            enabled: 0
+    uses: ./.github/workflows/clang-cross-download.yml
+    with:
+      runner: ubuntu-latest
+      workspace: /home/runner/work/${{ github.event.repository.name }}/${{ github.event.repository.name }}
+      assets: ${{ matrix.toolchain_asset }}
+      upload_artifact: true
+      artifact_name: clang-cross-${{ matrix.arch }}
+      enabled: ${{ matrix.enabled == 1 }}
+
+  build-busybox-with-eld:
+    if: github.repository == 'qualcomm/eld'
+    needs: fetch-clang-cross-toolchain
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - arch: x86_64
+            busybox_arch: x86_64
+            target_triple: x86_64-unknown-linux-musl
+            toolchain_dir: x86_64-unknown-linux-musl
+            qemu_bin: ""
+            enabled: 1
+          - arch: riscv32
+            busybox_arch: riscv
+            target_triple: riscv32-unknown-linux-musl
+            toolchain_dir: riscv32-unknown-linux-musl
+            qemu_bin: qemu-riscv32
+            enabled: 0
+          - arch: riscv64
+            busybox_arch: riscv
+            target_triple: riscv64-unknown-linux-musl
+            toolchain_dir: riscv64-unknown-linux-musl
+            qemu_bin: qemu-riscv64
+            enabled: 0
+          - arch: arm
+            busybox_arch: arm
+            target_triple: arm-unknown-linux-musleabi
+            toolchain_dir: arm-unknown-linux-musleabi
+            qemu_bin: qemu-arm
+            enabled: 0
+          - arch: aarch64
+            busybox_arch: aarch64
+            target_triple: aarch64-unknown-linux-musl
+            toolchain_dir: aarch64-unknown-linux-musl
+            qemu_bin: qemu-aarch64
+            enabled: 0
+    steps:
+      - name: Checkout eld
+        if: matrix.enabled == 1 && github.event_name != 'pull_request'
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          repository: qualcomm/eld
+          ref: main
+          fetch-depth: 1
+
+      - name: Checkout eld PR branch
+        if: matrix.enabled == 1 && github.event_name == 'pull_request'
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
+          ref: ${{ github.event.pull_request.head.ref }}
+          fetch-depth: 1
+
+      - name: Configure workflow environment variables
+        if: matrix.enabled == 1
+        uses: ./.github/workflows/ConfigureBuildWorkflowENV
+
+      - name: Record pre-build entry
+        if: github.event_name == 'schedule' && matrix.enabled == 1
+        uses: ./.github/workflows/BuildStatusDataRecorder
+        with:
+          enabled: true
+          project: "llvm-project/llvm/tools/eld"
+          stage: "pre-"
+          workflow-name: "busybox"
+          record-mode: "record"
+          status: "fail"
+          run-id: ${{github.run_id}}
+          arch-name: "${{ matrix.arch }}"
+          branch-name: "${{env.BUILD_BRANCH}}"
+
+      - name: Fetch latest nightly toolset
+        if: matrix.enabled == 1
+        uses: ./.github/workflows/FetchNightlyToolset
+
+      - name: Download clang-cross toolchain artifact
+        if: matrix.enabled == 1
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c #v8.0.1
+        with:
+          name: clang-cross-${{ matrix.arch }}
+          path: clang-cross
+
+      - name: Extract clang-cross toolchain
+        if: matrix.enabled == 1
+        shell: bash
+        env:
+          TOOLCHAIN_DIR: ${{ matrix.toolchain_dir }}
+        run: |
+          set -euo pipefail
+          mkdir -p "${{ github.workspace }}/${TOOLCHAIN_DIR}"
+          tar -xf clang-cross/clang-cross-*.tar -C "${{ github.workspace }}/${TOOLCHAIN_DIR}" --strip-components=1
+
+      - name: Resolve toolchain paths
+        if: matrix.enabled == 1
+        shell: bash
+        env:
+          TARGET_TRIPLE: ${{ matrix.target_triple }}
+          TOOLCHAIN_DIR: ${{ matrix.toolchain_dir }}
+        run: |
+          set -euo pipefail
+          toolchain_base="${{ github.workspace }}/${TOOLCHAIN_DIR}"
+          cross_root="$(find "${toolchain_base}" -type f -path "*/bin/${TARGET_TRIPLE}-clang" -print -quit | sed 's|/bin/.*$||')"
+          if [[ -z "${cross_root}" ]]; then
+            echo "Could not find ${TARGET_TRIPLE}-clang under ${toolchain_base}" >&2
+            find "${toolchain_base}" -maxdepth 4 -type d -name bin -print >&2 || true
+            exit 1
+          fi
+          eld_bin="$(command -v ld.eld || true)"
+          if [[ -z "${eld_bin}" ]]; then
+            echo "Could not find ld.eld in PATH after FetchNightlyToolset" >&2
+            exit 1
+          fi
+          echo "CROSS_TOOLCHAIN_ROOT=${cross_root}" >> "${GITHUB_ENV}"
+          echo "ELD_BIN=${eld_bin}" >> "${GITHUB_ENV}"
+          echo "${cross_root}/bin" >> "${GITHUB_PATH}"
+          echo "Using cross toolchain root: ${cross_root}"
+          echo "Using ld.eld: ${eld_bin}"
+
+      - name: Clone BusyBox
+        if: matrix.enabled == 1
+        shell: bash
+        run: |
+          git clone https://github.com/mirror/busybox.git
+
+      - name: Build BusyBox with ELD
+        if: matrix.enabled == 1
+        shell: bash
+        env:
+          CROSS_TOOLCHAIN_ROOT: ${{ env.CROSS_TOOLCHAIN_ROOT }}
+          TARGET_TRIPLE: ${{ matrix.target_triple }}
+          BUSYBOX_ARCH: ${{ matrix.busybox_arch }}
+          ELD_BIN: ${{ env.ELD_BIN }}
+        run: |
+          set -euo pipefail
+          command -v "${TARGET_TRIPLE}-clang"
+          command -v ld.eld
+          "${TARGET_TRIPLE}"-clang --version
+          "${ELD_BIN}" --version
+
+          SYSROOT="${CROSS_TOOLCHAIN_ROOT}/${TARGET_TRIPLE}/sysroot"
+          MUSL_LINKER="$(find "${SYSROOT}/lib" -name 'ld-musl-*.so.1' | head -1)"
+
+          cd busybox
+          make defconfig
+
+          make -j"$(nproc)" \
+            ARCH="${BUSYBOX_ARCH}" \
+            CC="${TARGET_TRIPLE}-clang --ld-path=${ELD_BIN}" \
+            HOSTCC=clang \
+            STRIP="${TARGET_TRIPLE}-strip" \
+            LDFLAGS="-Wl,-dynamic-linker,${MUSL_LINKER} -Wl,-rpath,${SYSROOT}/lib"
+
+      - name: Run BusyBox tests
+        if: matrix.enabled == 1
+        timeout-minutes: 5
+        shell: bash
+        run: |
+          set -euo pipefail
+          cd busybox/testsuite
+
+          # env --default-signal resets all signals (including SIGPIPE) to their
+          # default handlers before exec-ing the shell. This is necessary because
+          # the GitHub Actions runner sets SIGPIPE to SIG_IGN, which is inherited
+          # by all child processes and causes 'yes' in md5sum.tests to spin
+          # forever instead of dying when the pipe is closed by 'head'.
+          env SKIP_KNOWN_BUGS=1 SKIP_INTERNET_TESTS=1 env --default-signal /bin/sh ./runtest 2>&1 | tee /tmp/busybox-test-output.txt || true
+
+      - name: Validate test results with FileCheck
+        if: matrix.enabled == 1
+        shell: bash
+        run: |
+          FileCheck --input-file=/tmp/busybox-test-output.txt "${{ github.workspace }}/test/BusyBox/${{ matrix.arch }}/test-failures.txt"
+
+      - name: Update build entry
+        if: github.event_name == 'schedule' && matrix.enabled == 1
+        uses: ./.github/workflows/BuildStatusDataRecorder
+        with:
+          enabled: true
+          project: "llvm-project/llvm/tools/eld"
+          stage: "post-"
+          workflow-name: "busybox"
+          record-mode: "update"
+          status: "pass"
+          run-id: ${{github.run_id}}
+          arch-name: "${{ matrix.arch }}"
+          branch-name: "${{env.BUILD_BRANCH}}"

.github/workflows/ci.yml

@@ -12,6 +12,7 @@ on:
       - '.github/workflows/ci-win.yml'
       - '.github/workflows/clang-cross-download.yml'
       - '.github/workflows/clang-cross-schedule.yml'
+      - '.github/workflows/busybox-eld.yml'
       - '.github/workflows/nightly-musl-builder.yml'
       - '.github/workflows/picolibc-builder.yml'
       - '.github/workflows/nightly-test.yml'

.github/workflows/clang-cross-download.yml

@@ -17,20 +17,38 @@ on:
         description: "Comma-separated list of asset names to download"
         required: true
         type: string
+      upload_artifact:
+        description: "Upload extracted toolchains as a GitHub artifact"
+        required: false
+        type: boolean
+        default: false
+      artifact_name:
+        description: "Artifact name when upload_artifact is true"
+        required: false
+        type: string
+        default: "clang-cross-toolchains"
+      enabled:
+        description: "Set to false to skip this job entirely (used to disable matrix entries)"
+        required: false
+        type: boolean
+        default: true
 
 
 permissions:
   contents: write
 jobs:
   download:
+    if: ${{ inputs.enabled }}
     runs-on: ${{ inputs.runner }}
     steps:
       - name: Download and extract release assets
+        id: fetch
         shell: bash
         env:
           WORKSPACE: ${{ inputs.workspace }}
           ASSETS: ${{ inputs.assets }}
         run: |
+          set -euo pipefail
           api_url="https://api.github.com/repos/cross-tools/clang-cross/releases/latest"
           release_json="$(curl -fsSL "${api_url}")"
           tag="$(printf '%s' "${release_json}" | jq -r '.tag_name')"
@@ -114,3 +132,15 @@ jobs:
 
           echo "Symlinks in ${WORKSPACE}:"
           find "${WORKSPACE}" -maxdepth 1 -type l -lname "${root_dir}/*" -printf "%p -> %l\n"
+
+          artifact_tar="${RUNNER_TEMP}/clang-cross-${tag}.tar"
+          tar -cf "${artifact_tar}" -C "${base_dir}" .
+          echo "artifact_tar=${artifact_tar}" >> "${GITHUB_OUTPUT}"
+
+      - name: Upload extracted toolchains artifact
+        if: ${{ inputs.upload_artifact }}
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a #v7.0.1
+        with:
+          name: ${{ inputs.artifact_name }}
+          retention-days: 1
+          path: ${{ steps.fetch.outputs.artifact_tar }}

.github/workflows/update-build-dashboard-data.yml

@@ -42,6 +42,7 @@ jobs:
             python3 record_builds.py --workflow reverse_iterator --emit
             python3 record_builds.py --workflow release --emit
             python3 record_builds.py --workflow windows_nightly --emit
+            python3 record_builds.py --workflow busybox --emit
             rm -f record_builds.py build-status.db
             rm -rf ${DASH_DIR}
             cd ..

test/BusyBox/x86_64/test-failures.txt

@@ -0,0 +1,23 @@
+#BEGIN_COMMENT
+# BusyBox's awk_sub() implements gsub() by repeatedly calling regexec() while
+# advancing a pointer through the string. Correctly handling anchors like
+# \< (word start) on each iteration requires REG_STARTEND, a BSD/glibc regex
+# extension not present in POSIX. musl's regex.h defines no REG_STARTEND, so
+# the build falls back to the code path busybox's own source comments already
+# flag as buggy: it reruns regexec() on the advanced pointer, so the regex
+# engine treats that mid-string position as a word start too, and \<b* wrongly
+# matches the "b" in "abc". This is not a bug in BusyBox, the build, or the
+# linker, it is a missing non-POSIX regex extension (REG_STARTEND) in musl.
+#END_COMMENT
+CHECK: FAIL: awk gsub erroneous word start match
+
+#BEGIN_COMMENT
+# BusyBox's parse_datestr() parses this form via
+# strptime(date_str, "%Y-%m-%d %T %z", &tm). Accepting a bare 'Z' suffix as a
+# synonym for '+0000' in the %z conversion is a GNU libc extension, not POSIX
+# behavior. This is not a bug in BusyBox, the build, or the linker, it is a
+# glibc-vs-musl strptime behavioral difference.
+#END_COMMENT
+CHECK: FAIL: date-timezone
+
+CHECK-NOT: FAIL: