ci: Test with LLVM downloaded from Rust CI

vadorovsky · vadorovsky · commit 8518c78bfb97 · 2025-11-25T17:08:04.000+01:00
We are planning to use libLLVM from Rust CI to produce static binaries.
This change makes sure that tests work with Rust's libLLVM artifacts.

Rust CI ships only one flavor of libLLVM, shared or static, per target.
Linux GNU targets come with shared ones. Apple and Linux musl targets
come with dynamic ones.

To save disk space, run `cargo hack --feature-powerset` only when
shared libraries are used. Otherwise, run cargo with a single feature
set.
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -68,12 +68,33 @@ jobs:
             llvm: 21
             exclude-features: llvm-19,llvm-20,rust-llvm-19,rust-llvm-20
         platform:
+          # Rust CI ships only one flavor of libLLVM, shared or static, per
+          # target. Linux GNU targets come with shared ones. Apple and Linux
+          # musl targets come with dynamic ones.
           - os: macos-latest
+            static-target: aarch64-apple-darwin
+            # Rust does not provide a shared libLLVM library on macOS,
+            # therefore we exclude `default` and `rust-llvm-*`.
+            # macOS does not provide static libc++ and zlib and the ones
+            # provided by homebrew might be ABI-incompatible, therefore we
+            # exclude `llvm-deps-link-static`.
+            exclude-features: default,llvm-deps-link-static,rust-llvm-19,rust-llvm-20,rust-llvm-21
           - os: macos-15-intel
+            static-target: x86_64-apple-darwin
+            exclude-features: default,llvm-deps-link-static,rust-llvm-19,rust-llvm-20,rust-llvm-21
           - os: ubuntu-22.04
+            shared-target: x86_64-unknown-linux-gnu
+            static-target: x86_64-unknown-linux-musl
+            # Link dependencies like libc++, zlib, zstd statically on Linux.
+            llvm-features-static: llvm-deps-link-static
           - os: ubuntu-22.04-arm
+            shared-target: aarch64-unknown-linux-gnu
+            static-target: aarch64-unknown-linux-musl
+            llvm-features-static: llvm-deps-link-static
         llvm-from:
           - packages
+          - rust-ci-shared
+          - rust-ci-static
         include:
           # Currently we build LLVM from source only for Linux x86_64.
           - toolchain:
@@ -83,13 +104,34 @@ jobs:
             platform:
               os: ubuntu-22.04
             llvm-from: source
+        exclude:
+          # Rust CI does not provide LLVM 19 anymore.
+          - toolchain:
+              llvm: 19
+            llvm-from: rust-ci-shared
+          - toolchain:
+              llvm: 19
+            llvm-from: rust-ci-static
+          # There is no macOS target that Rust CI ships shared libraries for.
+          - platform:
+              os: macos-latest
+            llvm-from: rust-ci-shared
+          - platform:
+              os: macos-15-intel
+            llvm-from: rust-ci-shared
     name: os=${{ matrix.platform.os }} rustc=${{ matrix.toolchain.rust }} llvm-version=${{ matrix.toolchain.llvm }} llvm-from=${{ matrix.llvm-from }}
     needs: llvm
 
     env:
       RUST_BACKTRACE: full
-      LLVM_FEATURES: llvm-${{ matrix.toolchain.llvm }}
-      LLVM_EXCLUDE_FEATURES: llvm-deps-link-static,llvm-link-static,no-llvm-linking
+      # Features that have to be included for dynamic linking.
+      LLVM_FEATURES_DYNAMIC: llvm-${{ matrix.toolchain.llvm }}
+      # Features that have to be included for static linking.
+      LLVM_FEATURES_STATIC: llvm-${{ matrix.toolchain.llvm }},llvm-link-static
+      # Features that have to be excluded when running `cargo hack --feature-powerset`
+      # and intending to link dynamically.
+      LLVM_EXCLUDE_FEATURES_DYNAMIC: llvm-deps-link-static,llvm-link-static,no-llvm-linking
+      RUSTC_LLVM_INSTALL_DIR: /tmp/rustc-llvm
 
     steps:
       - uses: actions/checkout@v6
@@ -126,17 +168,28 @@ jobs:
         # [1] https://github.com/llvm/llvm-project/commit/dc1c43d
         run: echo /usr/lib/llvm-15/bin >> $GITHUB_PATH
 
-      - name: Install LLVM (Linux, packages)
-        if: matrix.llvm-from == 'packages' && runner.os == 'Linux'
+      - name: Add LLVM APT repository
+        if: runner.os == 'Linux'
         run: |
           set -euxo pipefail
           wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
           echo -e deb http://apt.llvm.org/jammy/ llvm-toolchain-jammy-${{ matrix.toolchain.llvm }} main | sudo tee /etc/apt/sources.list.d/llvm.list
-
           sudo apt update
+
+      - name: Install LLVM (Linux, packages)
+        if: matrix.llvm-from == 'packages' && runner.os == 'Linux'
+        run: |
+          set -euxo pipefail
           sudo apt -y install llvm-${{ matrix.toolchain.llvm }}-dev
           echo /usr/lib/llvm-${{ matrix.toolchain.llvm }}/bin >> $GITHUB_PATH
 
+      - name: Install FileCheck (Linux)
+        if: (matrix.llvm-from == 'rust-ci-shared' || matrix.llvm-from == 'rust-ci-static') && runner.os == 'Linux'
+        run: |
+          set -euxo pipefail
+          sudo apt -y install llvm-${{ matrix.toolchain.llvm }}-tools
+          echo /usr/lib/llvm-${{ matrix.toolchain.llvm }}/bin >> $GITHUB_PATH
+
       - name: Install LLVM (macOS, packages)
         if: matrix.llvm-from == 'packages' && runner.os == 'macOS'
         run: |
@@ -145,7 +198,31 @@ jobs:
           echo $(brew --prefix llvm@${{ matrix.toolchain.llvm }})/bin >> $GITHUB_PATH
           echo "DYLD_LIBRARY_PATH=$(brew --prefix llvm@${{ matrix.toolchain.llvm }})/lib" >> $GITHUB_ENV
 
-      - name: Restore LLVM
+      - name: Install LLVM from Rust CI
+        if: matrix.llvm-from == 'rust-ci-shared' || matrix.llvm-from == 'rust-ci-static'
+        run: |
+          set -euxo pipefail
+          mkdir -p $RUSTC_LLVM_INSTALL_DIR
+          rustc_sha=$(cargo xtask rustc-llvm-commit --github-token ${{ secrets.GITHUB_TOKEN }})
+          if [[ "${{ matrix.llvm-from }}" == "rust-ci-shared" ]]; then
+            target="${{ matrix.platform['shared-target'] }}"
+          else
+            target="${{ matrix.platform['static-target'] }}"
+          fi
+          wget -q -O - "https://ci-artifacts.rust-lang.org/rustc-builds/$rustc_sha/rust-dev-nightly-$target.tar.xz" | \
+            tar -xJ --strip-components 2 -C $RUSTC_LLVM_INSTALL_DIR
+          echo "${RUSTC_LLVM_INSTALL_DIR}/bin" >> $GITHUB_PATH
+          if [[ "${{ matrix.llvm-from }}" == "rust-ci-shared" ]]; then
+            echo "LD_LIBRARY_PATH=${RUSTC_LLVM_INSTALL_DIR}/lib" >> $GITHUB_ENV
+          fi
+          # `FileCheck` binary shipped in musl tarballs is linked dynamically
+          # to musl, we can't execute it on Ubuntu.
+          if [[ "${{ runner.os }}" == "Linux"
+                && "${{ matrix.llvm-from }}" == "rust-ci-static" ]]; then
+            rm -f "${RUSTC_LLVM_INSTALL_DIR}/bin/FileCheck"
+          fi
+
+      - name: Restore LLVM from our GitHub cache
         if: matrix.llvm-from == 'source'
         uses: actions/cache/restore@v4
         with:
@@ -172,17 +249,37 @@ jobs:
 
       - uses: taiki-e/install-action@cargo-hack
 
-      - name: Check
+      - name: Check (dynamic linking, feature powerset)
+        # Static linking in combination with `cargo hack --feature-powerset`
+        # (multiple builds) increases the disk usage massively.
+        if: matrix.llvm-from != 'rust-ci-static'
         run: |
           cargo hack check --feature-powerset \
-            --exclude-features ${{ env.LLVM_EXCLUDE_FEATURES }},${{ matrix.toolchain.exclude-features }} \
-            --features ${{ env.LLVM_FEATURES }}
+            --exclude-features \
+            ${{ env.LLVM_EXCLUDE_FEATURES_DYNAMIC }},${{ matrix.toolchain.exclude-features }},${{ matrix.platform.exclude-features }} \
+            --features ${{ env.LLVM_FEATURES_DYNAMIC }}
+
+      - name: Check (static linking, single feature set)
+        if: matrix.llvm-from == 'rust-ci-static'
+        run: |
+          cargo check --no-default-features \
+            --features \
+            ${{ env.LLVM_FEATURES_STATIC }},${{ matrix.platform.llvm-features-static }}
 
-      - name: Build
+      - name: Build (dynamic linking, feature powerset)
+        if: matrix.llvm-from != 'rust-ci-static'
         run: |
           cargo hack build --feature-powerset \
-            --exclude-features ${{ env.LLVM_EXCLUDE_FEATURES }},${{ matrix.toolchain.exclude-features }} \
-            --features ${{ env.LLVM_FEATURES }}
+            --exclude-features \
+            ${{ env.LLVM_EXCLUDE_FEATURES_DYNAMIC }},${{ matrix.toolchain.exclude-features }},${{ matrix.platform.exclude-features }} \
+            --features ${{ env.LLVM_FEATURES_DYNAMIC }}
+
+      - name: Build (static linking, single feature set)
+        if: matrix.llvm-from == 'rust-ci-static'
+        run: |
+          cargo build --no-default-features \
+            --features \
+            ${{ env.LLVM_FEATURES_STATIC }},${{ matrix.platform.llvm-features-static }}
 
       # Toolchains provided by rustup include standard library artifacts
       # only for Tier 1 targets, which do not include BPF targets.
@@ -192,11 +289,20 @@ jobs:
       # running compiler tests.
       #
       # `RUSTC_BOOTSTRAP` is needed to use `rustc-build-sysroot` on stable Rust.
-      - name: Test (sysroot built on demand)
+      - name: Test (sysroot built on demand, dynamic linking)
+        if: matrix.llvm-from != 'rust-ci-static'
         run: |
           RUSTC_BOOTSTRAP=1 cargo hack test --feature-powerset \
-            --exclude-features ${{ env.LLVM_EXCLUDE_FEATURES }},${{ matrix.toolchain.exclude-features }} \
-            --features ${{ env.LLVM_FEATURES }}
+            --exclude-features \
+            ${{ env.LLVM_EXCLUDE_FEATURES_DYNAMIC }},${{ matrix.toolchain.exclude-features }},${{ matrix.platform.exclude-features }} \
+            --features ${{ env.LLVM_FEATURES_DYNAMIC }}
+
+      - name: Test (sysroot built on demand, static linking)
+        if: matrix.llvm-from == 'rust-ci-static'
+        run: |
+          RUSTC_BOOTSTRAP=1 cargo test --no-default-features \
+            --features \
+             ${{ env.LLVM_FEATURES_STATIC }},${{ matrix.platform.llvm-features-static }}
 
       # To make things easier for package maintainers, the step of building a
       # custom sysroot can be skipped by setting the `BPFEL_SYSROOT_DIR`
@@ -207,7 +313,7 @@ jobs:
       #
       # `RUSTC_BOOTSTRAP` is needed to make `xtask build-std` work on stable
       # Rust.
-      - name: Test (prebuilt BPF standard library)
+      - name: Build BPF standard library
         run: |
           set -euxo pipefail
 
@@ -217,10 +323,24 @@ jobs:
             --rustc-src "$RUSTC_SRC" \
             --sysroot-dir "$BPFEL_SYSROOT_DIR" \
             --target bpfel-unknown-none
+          echo "BPFEL_SYSROOT_DIR=${BPFEL_SYSROOT_DIR}" >> $GITHUB_ENV
 
+      - name: Test (prebuilt BPF standard libary, dynamic linking)
+        if: matrix.llvm-from != 'rust-ci-static'
+        run: |
+          set -euxo pipefail
           BPFEL_SYSROOT_DIR="$BPFEL_SYSROOT_DIR" cargo hack test --feature-powerset \
-            --exclude-features ${{ env.LLVM_EXCLUDE_FEATURES }},${{ matrix.toolchain.exclude-features }} \
-            --features ${{ env.LLVM_FEATURES }}
+            --exclude-features \
+            ${{ env.LLVM_EXCLUDE_FEATURES_DYNAMIC }},${{ matrix.toolchain.exclude-features }},${{ matrix.platform.exclude-features }} \
+            --features ${{ env.LLVM_FEATURES_DYNAMIC }}
+
+      - name: Test (prebuilt BPF standard library, static linking)
+        if: matrix.llvm-from == 'rust-ci-static'
+        run: |
+          set -euxo pipefail
+          BPFEL_SYSROOT_DIR="$BPFEL_SYSROOT_DIR" cargo test --no-default-features \
+            --features \
+            ${{ env.LLVM_FEATURES_STATIC }},${{ matrix.platform.llvm-features-static }}
 
       - uses: actions/checkout@v6
         if: runner.os == 'Linux' && matrix.toolchain.rust == 'nightly'
@@ -229,9 +349,16 @@ jobs:
           path: aya
           submodules: recursive
 
-      - name: Install
-        if: runner.os == 'Linux' && matrix.toolchain.rust == 'nightly'
-        run: cargo install --path . --no-default-features --features ${{ env.LLVM_FEATURES }}
+      - name: Install (dynamic linking)
+        if: runner.os == 'Linux' && matrix.toolchain.rust == 'nightly' && matrix.llvm-from != 'rust-ci-static'
+        run: |
+          cargo install --path . --no-default-features --features \
+            ${{ env.LLVM_FEATURES_DYNAMIC }}
+
+      - name: Install (static linking)
+        if: runner.os == 'Linux' && matrix.toolchain.rust == 'nightly' && matrix.llvm-from == 'rust-ci-static'
+        run: cargo install --path . --no-default-features --features \
+          ${{ env.LLVM_FEATURES_STATIC }},${{ matrix.platform.llvm-features-static }}
 
       - name: Run aya integration tests
         if: runner.os == 'Linux' && matrix.toolchain.rust == 'nightly'
