also test on x86-32 and arm-64 linux hosts

Author: RalfJung

.github/workflows/ci.yml

@@ -13,35 +13,55 @@ defaults:
     shell: bash
 
 jobs:
-  build:
+  test:
+    name: build and test on ${{ matrix.host_target }}
     strategy:
       fail-fast: false
       matrix:
         include:
-          - os: ubuntu-latest
-            host_target: x86_64-unknown-linux-gnu
-          - os: macos-14
-            host_target: aarch64-apple-darwin
-          - os: windows-latest
-            host_target: i686-pc-windows-msvc
+          - host_target: x86_64-unknown-linux-gnu
+            os: ubuntu-latest
+          # Needs a libffi patch: <https://github.com/libffi-rs/libffi-rs/pull/160>
+          # - host_target: i686-unknown-linux-gnu
+          #   os: ubuntu-latest
+          - host_target: aarch64-unknown-linux-gnu
+            os: ubuntu-24.04-arm
+          # Disabled due to <https://github.com/rust-lang/rust/issues/143184>.
+          - host_target: armv7-unknown-linux-gnueabihf
+            os: ubuntu-24.04-arm
+          - host_target: aarch64-apple-darwin
+            os: macos-latest
+          - host_target: i686-pc-windows-msvc
+            os: windows-latest
     runs-on: ${{ matrix.os }}
     env:
       HOST_TARGET: ${{ matrix.host_target }}
     steps:
       - uses: actions/checkout@v4
+      - name: Install multilib dependencies
+        if: ${{ matrix.host_target == 'i686-unknown-linux-gnu' }}
+        run: |
+          sudo dpkg --add-architecture i386
+          sudo apt update
+          sudo apt install gcc-multilib zlib1g-dev:i386 libffi-dev:i386
+      - name: Install multilib dependencies
+        if: ${{ matrix.host_target == 'armv7-unknown-linux-gnueabihf' }}
+        run: |
+          sudo dpkg --add-architecture armhf
+          sudo apt update
+          sudo apt install gcc-arm-linux-gnueabihf zlib1g-dev:armhf libffi-dev:armhf
       - uses: ./.github/workflows/setup
         with:
           toolchain_flags: "--host ${{ matrix.host_target }}"
 
-      # The `style` job only runs on Linux; this makes sure the Windows-host-specific
+      - name: Test Miri
+        run: ./ci/ci.sh
+
+      # The `style` job only runs on Linux; this makes sure the host-specific
       # code is also covered by clippy.
       - name: Check clippy
-        if: ${{ matrix.os == 'windows-latest' }}
         run: ./miri clippy -- -D warnings
 
-      - name: Test Miri
-        run: ./ci/ci.sh
-
   style:
     name: style checks
     runs-on: ubuntu-latest
@@ -73,7 +93,7 @@ jobs:
   # ALL THE PREVIOUS JOBS NEED TO BE ADDED TO THE `needs` SECTION OF THIS JOB!
   # And they should be added below in `cron-fail-notify` as well.
   conclusion:
-    needs: [build, style, coverage]
+    needs: [test, style, coverage]
     # We need to ensure this job does *not* get skipped if its dependencies fail,
     # because a skipped job is considered a success by GitHub. So we have to
     # overwrite `if:`. We use `!cancelled()` to ensure the job does still not get run
@@ -135,7 +155,7 @@ jobs:
   cron-fail-notify:
     name: cronjob failure notification
     runs-on: ubuntu-latest
-    needs: [build, style, coverage]
+    needs: [test, style, coverage]
     if: ${{ github.event_name == 'schedule' && failure() }}
     steps:
       # Send a Zulip notification

.github/workflows/setup/action.yml

@@ -2,6 +2,7 @@ name: "Miri CI setup"
 description: "Sets up Miri CI"
 inputs:
   toolchain_flags:
+    description: extra flags to pass to rustup-toolchain-install-master
     required: false
     default: ''
 runs:
@@ -31,8 +32,9 @@ runs:
             ~/.cargo/bin
             ~/.cargo/.crates.toml
             ~/.cargo/.crates2.json
-          key: cargo-${{ runner.os }}-${{ hashFiles('**/Cargo.lock', '.github/workflows/**/*.yml') }}
-          restore-keys: cargo-${{ runner.os }}
+          # Bump the version when something here changes that needs a cache reset.
+          key: cargo-${{ runner.os }}-${{ runner.arch }}-${{ hashFiles('**/Cargo.lock') }}-v1
+          restore-keys: cargo-${{ runner.os }}-${{ runner.arch }}
 
       - name: Install rustup-toolchain-install-master
         if: steps.cache.outputs.cache-hit != 'true'

Cargo.lock

@@ -37,7 +37,7 @@ features = ['unprefixed_malloc_on_supported_platforms']
 
 [target.'cfg(unix)'.dependencies]
 libc = "0.2"
-libffi = "4.0.0"
+libffi = { git = "https://github.com/RalfJung/libffi-rs", branch = "multilib" }
 libloading = "0.8"
 
 [target.'cfg(target_os = "linux")'.dependencies]

Cargo.toml

@@ -28,6 +28,11 @@ begingroup "Building Miri"
 export RUSTFLAGS="-D warnings"
 export CARGO_INCREMENTAL=0
 export CARGO_EXTRA_FLAGS="--locked"
+case $HOST_TARGET in
+  armv7-unknown-linux-gnueabihf)
+    RUSTFLAGS="$RUSTFLAGS -Clinker=arm-linux-gnueabihf-gcc"
+    ;;
+esac
 
 # Determine configuration for installed build (used by test-cargo-miri and `./miri bench`).
 echo "Installing release version of Miri"
@@ -142,13 +147,22 @@ case $HOST_TARGET in
     # Host
     GC_STRESS=1 MIR_OPT=1 MANY_SEEDS=64 TEST_BENCH=1 CARGO_MIRI_ENV=1 run_tests
     # Extra tier 1
-    MANY_SEEDS=64 TEST_TARGET=i686-unknown-linux-gnu run_tests
     MANY_SEEDS=64 TEST_TARGET=aarch64-unknown-linux-gnu run_tests
     MANY_SEEDS=64 TEST_TARGET=x86_64-apple-darwin run_tests
     MANY_SEEDS=64 TEST_TARGET=x86_64-pc-windows-gnu run_tests
+    ;;
+  i686-unknown-linux-gnu)
+    # Host
+    GC_STRESS=1 MIR_OPT=1 MANY_SEEDS=64 TEST_BENCH=1 CARGO_MIRI_ENV=1 run_tests
     # Extra tier 1 candidate
     MANY_SEEDS=64 TEST_TARGET=aarch64-pc-windows-msvc run_tests
     ;;
+  aarch64-unknown-linux-gnu)
+    # Host
+    GC_STRESS=1 MIR_OPT=1 MANY_SEEDS=64 TEST_BENCH=1 CARGO_MIRI_ENV=1 run_tests
+    # Custom target JSON file
+    TEST_TARGET=tests/x86_64-unknown-kernel.json MIRI_NO_STD=1 run_tests_minimal no_std
+    ;;
   aarch64-apple-darwin)
     # Host
     GC_STRESS=1 MIR_OPT=1 MANY_SEEDS=64 TEST_BENCH=1 CARGO_MIRI_ENV=1 run_tests
@@ -172,13 +186,10 @@ case $HOST_TARGET in
     TEST_TARGET=wasm32-wasip2          run_tests_minimal $BASIC wasm
     TEST_TARGET=wasm32-unknown-unknown run_tests_minimal no_std empty_main wasm # this target doesn't really have std
     TEST_TARGET=thumbv7em-none-eabihf  run_tests_minimal no_std
-    # Custom target JSON file
-    TEST_TARGET=tests/x86_64-unknown-kernel.json MIRI_NO_STD=1 run_tests_minimal no_std
     ;;
   i686-pc-windows-msvc)
     # Host
-    # Without GC_STRESS and with reduced many-seeds count as this is the slowest runner.
-    # (The macOS runner checks windows-msvc with full many-seeds count.)
+    # Without GC_STRESS as this is the slowest runner.
     MIR_OPT=1 MANY_SEEDS=64 TEST_BENCH=1 run_tests
     # Extra tier 1
     # We really want to ensure a Linux target works on a Windows host,