Add riscv32 CI run

Author: sayantn

.github/workflows/main.yml

@@ -56,6 +56,8 @@ jobs:
           os: ubuntu-latest
         - tuple: aarch64-unknown-linux-gnu
           os: ubuntu-latest
+        - tuple: riscv32gc-unknown-linux-gnu
+          os: ubuntu-latest
         - tuple: riscv64gc-unknown-linux-gnu
           os: ubuntu-latest
         - tuple: powerpc-unknown-linux-gnu
@@ -148,6 +150,11 @@ jobs:
             os: ubuntu-latest
           disable_assert_instr: true
           test_everything: true
+        - target:
+            tuple: riscv32gc-unknown-linux-gnu
+            os: ubuntu-latest
+          test_everything: true
+          build_std: true
         - target:
             tuple: riscv64gc-unknown-linux-gnu
             os: ubuntu-latest
@@ -193,13 +200,18 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
-      with:
-        submodules: recursive
+
     - name: Install Rust
       run: |
         rustup update nightly --no-self-update
         rustup default nightly
     - run: rustup target add ${{ matrix.target.tuple }}
+      if: matrix.build_std == ''
+    - run: |
+        rustup component add rust-src
+        echo "CARGO_UNSTABLE_BUILD_STD=std" >> $GITHUB_ENV
+      if: matrix.build_std != ''
+
     - run: cargo generate-lockfile
 
     # Configure some env vars based on matrix configuration
@@ -228,7 +240,7 @@ jobs:
     # ... while Linux goes to `run-docker.sh`
     - run: ./ci/run-docker.sh ${{ matrix.target.tuple }}
       shell: bash
-      if: "matrix.target.os == 'ubuntu-latest' && !startsWith(matrix.target.tuple, 'thumb')"
+      if: matrix.target.os == 'ubuntu-latest' && !startsWith(matrix.target.tuple, 'thumb')
       env:
         TARGET: ${{ matrix.target.tuple }}
 

ci/docker/riscv32gc-unknown-linux-gnu/Dockerfile

@@ -0,0 +1,15 @@
+FROM ubuntu:25.04
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        gcc libc6-dev qemu-user ca-certificates \
+        wget xz-utils make file llvm
+
+ENV VERSION=2025.01.20
+
+RUN wget "https://github.com/riscv-collab/riscv-gnu-toolchain/releases/download/${VERSION}/riscv32-glibc-ubuntu-24.04-gcc-nightly-${VERSION}-nightly.tar.xz" \
+    -O riscv-toolchain.tar.xz
+RUN tar -xJf riscv-toolchain.tar.xz
+
+ENV CARGO_TARGET_RISCV32GC_UNKNOWN_LINUX_GNU_LINKER=/riscv/bin/riscv32-unknown-linux-gnu-gcc \
+    CARGO_TARGET_RISCV32GC_UNKNOWN_LINUX_GNU_RUNNER="qemu-riscv32 -cpu max -L /riscv/sysroot" \
+    OBJDUMP=llvm-objdump

ci/run-docker.sh

@@ -27,6 +27,7 @@ run() {
       --env NOSTD \
       --env NORUN \
       --env RUSTFLAGS \
+      --env CARGO_UNSTABLE_BUILD_STD \
       --volume "${HOME}/.cargo":/cargo \
       --volume "$(rustc --print sysroot)":/rust:ro \
       --volume "$(pwd)":/checkout:ro \

crates/stdarch-test/src/disassembly.rs

@@ -77,7 +77,7 @@ pub(crate) fn disassemble_myself() -> HashSet<Function> {
     let add_args = if cfg!(target_vendor = "apple") && cfg!(target_arch = "aarch64") {
         // Target features need to be enabled for LLVM objdump on Darwin ARM64
         vec!["--mattr=+v8.6a,+crypto,+tme"]
-    } else if cfg!(target_arch = "riscv64") {
+    } else if cfg!(any(target_arch = "riscv32", target_arch = "riscv64")) {
         vec!["--mattr=+zk,+zks,+zbc,+zbb"]
     } else {
         vec![]