ci: build libc++abi.a for musl with -fPIC

.github/workflows/libc++abi.yml

@@ -0,0 +1,85 @@
+name: Build libc++abi
+
+on:
+  push:
+    branches:
+      - release-libc++abi
+    tags-ignore:
+      - '**'
+
+permissions:
+  contents: write
+  id-token: write
+  attestations: write
+
+jobs:
+  setup-llvm-version:
+    runs-on: ubuntu-latest
+    outputs:
+      llvm-version: ${{ steps.setup-llvm-version.outputs.llvm-version }}
+    steps:
+      - name: Setup
+        id: setup-llvm-version
+        run: |
+          echo "llvm-version=$(cat llvm-version)" >> $GITHUB_OUTPUT
+
+  build-musl:
+    runs-on: ${{ matrix.settings.runs-on }}
+    needs: setup-llvm-version
+    name: Build libc++abi for ${{ matrix.settings.arch }} Linux musl
+    strategy:
+      matrix:
+        settings:
+          - { arch: x86_64, runs-on: ubuntu-latest }
+          - { arch: aarch64, runs-on: ubuntu-24.04-arm }
+    steps:
+      - name: Build in docker
+        uses: addnab/docker-run-action@v3
+        with:
+          image: node:18-alpine
+          options: -v ${{ github.workspace }}:/build -w /build
+          run: |
+            apk add clang llvm wget unzip cmake ninja xz tar musl-dev python3
+            node scripts/build-c++abi.mjs
+      - uses: actions/attest-build-provenance@v2
+        with:
+          subject-path: |
+            libc++abi.a
+      - name: Upload
+        uses: actions/upload-artifact@v4
+        with:
+          name: libc++abi-${{ matrix.settings.arch }}.a
+          path: libc++abi.a
+
+  release:
+    needs:
+      - setup-llvm-version
+      - build-musl
+    runs-on: ubuntu-latest
+    steps:
+      - name: Download x86_64
+        uses: actions/download-artifact@v4
+        with:
+          name: libc++abi-x86_64.a
+          path: .
+      - name: Rename
+        run: |
+          mv libc++abi.a libc++abi-x86_64.a
+      - name: Download aarch64
+        uses: actions/download-artifact@v4
+        with:
+          name: libc++abi-aarch64.a
+          path: .
+      - name: Rename
+        run: |
+          mv libc++abi.a libc++abi-aarch64.a
+      - name: Release
+        uses: softprops/action-gh-release@v2
+        with:
+          files: |
+            libc++abi-x86_64.a
+            libc++abi-aarch64.a
+          name: libc++abi-${{ needs.setup-llvm-version.outputs.llvm-version }}
+          tag_name: libc++abi-${{ needs.setup-llvm-version.outputs.llvm-version }}
+          make_latest: false
+

llvm-version

@@ -0,0 +1 @@
+19.1.7

musl.Dockerfile

@@ -18,7 +18,6 @@ RUN apk add --no-cache \
   libc++-dev \
   libc++-static \
   llvm-libunwind-static \
-  libc++-dev \
   tar \
   xz \
   ninja && \

scripts/build-c++abi.mjs

@@ -1,37 +1,43 @@
-import { execSync } from "node:child_process";
+import { execSync } from 'node:child_process'
+import { readFileSync } from 'node:fs'
+import { fileURLToPath } from 'node:url'
+import { join } from 'node:path'
 
-const LLVM_VERSION = "19.1.7";
+const LLVM_VERSION = readFileSync(join(fileURLToPath(import.meta.url), '..', '..', 'llvm-version'), 'utf-8').trim()
 
 execSync(`wget https://github.com/llvm/llvm-project/archive/refs/tags/llvmorg-${LLVM_VERSION}.zip`, {
-  stdio: "inherit",
-});
+  stdio: 'inherit',
+})
 
 execSync(`unzip llvmorg-${LLVM_VERSION}.zip`, {
-  stdio: "inherit",
-});
+  stdio: 'inherit',
+})
 
 execSync(`mkdir -p build`, {
-  stdio: "inherit",
+  stdio: 'inherit',
   cwd: `llvm-project-llvmorg-${LLVM_VERSION}`,
-});
+})
 
-execSync(`cmake -G Ninja -S runtimes -B build -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi;libunwind" -DLIBCXX_ENABLE_LOCALIZATION=OFF`, {
-  stdio: "inherit",
-  cwd: `llvm-project-llvmorg-${LLVM_VERSION}`,
-  env: {
-    ...process.env,
-    CXX: "clang++",
-    CC: "clang",
-    CXXFLAGS: "-fPIC",
+execSync(
+  `cmake -G Ninja -S runtimes -B build -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi;libunwind" -DLIBCXX_ENABLE_LOCALIZATION=OFF`,
+  {
+    stdio: 'inherit',
+    cwd: `llvm-project-llvmorg-${LLVM_VERSION}`,
+    env: {
+      ...process.env,
+      CXX: 'clang++',
+      CC: 'clang',
+      CXXFLAGS: '-fPIC',
+    },
   },
-});
+)
 
 execSync(`ninja -C build cxxabi`, {
-  stdio: "inherit",
+  stdio: 'inherit',
   cwd: `llvm-project-llvmorg-${LLVM_VERSION}`,
-});
+})
 
-execSync(`cp build/lib/libc++abi.a /usr/lib/libc++abi.a`, {
-  stdio: "inherit",
+execSync(`cp llvm-project-llvmorg-${LLVM_VERSION}/build/lib/libc++abi.a .`, {
+  stdio: 'inherit',
   cwd: `llvm-project-llvmorg-${LLVM_VERSION}`,
-});
+})