Run rust tests with GCC backend

src/ci/docker/host-x86_64/x86_64-gnu-gcc/Dockerfile

@@ -0,0 +1,45 @@
+FROM ubuntu:22.04
+
+ARG DEBIAN_FRONTEND=noninteractive
+RUN apt-get update && apt-get install -y --no-install-recommends \
+  bzip2 \
+  g++ \
+  make \
+  ninja-build \
+  file \
+  curl \
+  ca-certificates \
+  python3 \
+  git \
+  cmake \
+  sudo \
+  gdb \
+  libssl-dev \
+  pkg-config \
+  xz-utils \
+  mingw-w64 \
+  zlib1g-dev \
+  libzstd-dev \
+  # libgccjit dependencies
+  flex \
+  libmpfr-dev \
+  libgmp-dev \
+  libmpc3 \
+  libmpc-dev \
+  && rm -rf /var/lib/apt/lists/*
+
+COPY scripts/sccache.sh /scripts/
+RUN sh /scripts/sccache.sh
+
+ENV RUST_CONFIGURE_ARGS \
+ --build=x86_64-unknown-linux-gnu \
+ --enable-sanitizers \
+ --enable-profiler \
+ --enable-compiler-docs \
+ --set llvm.libzstd=true \
+ --set 'rust.codegen-backends=[\"llvm\",\"gcc\"]'
+ENV SCRIPT python3 ../x.py \
+  --stage 2 \
+  test \
+  --test-codegen-backend gcc \
+  --set 'rust.codegen-backends=[\"llvm\",\"gcc\"]'

src/ci/github-actions/jobs.yml

@@ -141,6 +141,9 @@ pr:
     <<: *job-linux-4c
   - name: x86_64-gnu-miri
     <<: *job-linux-4c
+  - name: x86_64-gnu-gcc
+    doc_url: https://rustc-dev-guide.rust-lang.org/tests/codegen-backend-tests/cg_gcc.html
+    <<: *job-linux-4c
 
 # Jobs that run when you perform a try build (@bors try)
 # These jobs automatically inherit envs.try, to avoid repeating
@@ -348,6 +351,10 @@ auto:
   - name: x86_64-gnu
     <<: *job-linux-4c
 
+  - name: x86_64-gnu-gcc
+    doc_url: https://rustc-dev-guide.rust-lang.org/tests/codegen-backend-tests/cg_gcc.html
+    <<: *job-linux-4c
+
   # This job ensures commits landing on nightly still pass the full
   # test suite on the stable channel. There are some UI tests that
   # depend on the channel being built (for example if they include the

src/ci/run.sh

@@ -188,7 +188,9 @@ else
   fi
 
   # Download GCC from CI on test builders
-  RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --set gcc.download-ci-gcc=true"
+  # FIXME: Temporarily commented out until the GCC build/download strategy is cleared out or
+  # made dependent on GCC submodule changes.
+  # RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --set gcc.download-ci-gcc=true"
 
   # download-rustc seems to be broken on CI after the stage0 redesign
   # Disable it until these issues are debugged and resolved