github/workflows: Add 32-bit OBJ_REPR_B CI job.

This showed up some interesting errors (hopefully all fixed now).

Signed-off-by: Jeff Epler <jepler@unpythonic.net>

.github/workflows/ports_unix.yml

@@ -217,6 +217,20 @@ jobs:
       if: failure()
       run: tests/run-tests.py --print-failures
 
+  repr_b:
+    runs-on: ubuntu-22.04 # use 22.04 to get libffi-dev:i386
+    steps:
+    - uses: actions/checkout@v5
+    - name: Install packages
+      run: source tools/ci.sh && ci_unix_32bit_setup
+    - name: Build
+      run: source tools/ci.sh && ci_unix_repr_b_build
+    - name: Run main test suite
+      run: source tools/ci.sh && ci_unix_repr_b_run_tests
+    - name: Print failures
+      if: failure()
+      run: tests/run-tests.py --print-failures
+
   macos:
     runs-on: macos-latest
     steps:

tools/ci.sh

@@ -556,6 +556,14 @@ CI_UNIX_OPTS_SANITIZE_UNDEFINED=(
     LDFLAGS_EXTRA="-fsanitize=undefined -fno-sanitize=nonnull-attribute"
 )
 
+CI_UNIX_OPTS_REPR_B=(
+    VARIANT=standard
+    CFLAGS_EXTRA="-DMICROPY_OBJ_REPR=MICROPY_OBJ_REPR_B -DMICROPY_PY_UCTYPES=0 -Dmp_int_t=int32_t -Dmp_uint_t=uint32_t"
+    MICROPY_FORCE_32BIT=1
+    RUN_TESTS_MPY_CROSS_FLAGS="--mpy-cross-flags=\"-march=x86 -msmall-int-bits=30\""
+
+)
+
 function ci_unix_build_helper {
     make ${MAKEOPTS} -C mpy-cross
     make ${MAKEOPTS} -C ports/unix "$@" submodules
@@ -898,6 +906,17 @@ function ci_unix_qemu_riscv64_run_tests {
     (cd tests && MICROPY_MICROPYTHON=../ports/unix/build-coverage/micropython MICROPY_TEST_TIMEOUT=180 ./run-tests.py --exclude 'thread/stress_recurse.py|thread/thread_gc1.py')
 }
 
+function ci_unix_repr_b_build {
+    ci_unix_build_helper "${CI_UNIX_OPTS_REPR_B[@]}"
+    ci_unix_build_ffi_lib_helper gcc -m32
+}
+
+function ci_unix_repr_b_run_tests {
+    # ci_unix_run_tests_full_no_native_helper is not used due to
+    # https://github.com/micropython/micropython/issues/18105
+    ci_unix_run_tests_helper "${CI_UNIX_OPTS_REPR_B[@]}"
+}
+
 ########################################################################################
 # ports/windows