Re: [OE-core] [PATCH 2/2] rust-common.bbclass: filter out incorrect compiler flags in wrapper

["Mathieu Dubois-Briand" <mathieu.dubois-briand@bootlin.com>]

On Thu Nov 20, 2025 at 1:19 PM CET, Gyorgy Sarvari via lists.openembedded.org wrote:
> This patch is a workaround for https://bugzilla.yoctoproject.org/show_bug.cgi?id=15976
>
> cc-rs crate is used by a number of projects, including rust's bootstrap also
> to invoke the systems c/c++ compiler.
>
> A few updates ago it has changed the way CFLAGS/CXXFLAGS are handled: it now
> merges them with HOST_C*FLAGS and TARGET_C*FLAGS.
>
> This is a problem when a recipe is cross compiled, but it has a build dependency
> which uses this crate to be built. In this case the C*FLAGS variable contains
> target flags, while the HOST_C*FLAGS contains host-specific flags, and when the
> two are mixed, the output is not what one expects.
>
> This change tries to filter out the incorrect flags:
> - If the wrapper is invoked as a c or c++ compiler wrapper,
> - then determines if it compiles for host or for target
> - Depending on the on above, it considers the TARGET_*FLAGS or HOST*FLAGS
>   correct, and the C*FLAGS variable content incorrect.
> - It subtracts the correct set from the incorrect set, and drops the
>   remainder from the compiler flags. (Which might be often an empty list, so
>   the flags are frequently unchanged)
>
> Signed-off-by: Gyorgy Sarvari <skandigraun@gmail.com>
> ---

Hi Gyorgy,

Thanks for your patch.

I suspect one of the commit of this series is responsible of this rust
test failure:

2025-11-20 21:59:48,098 - oe-selftest - INFO - FAIL: rust.RustSelfTestSystemEmulated.test_rust (subunit.RemotedTestCase)
...
  File "/srv/pokybuild/yocto-worker/qemux86-64-tc/build/layers/openembedded-core/meta/lib/oeqa/core/decorator/__init__.py", line 35, in wrapped_f
    return func(*args, **kwargs)
  File "/srv/pokybuild/yocto-worker/qemux86-64-tc/build/layers/openembedded-core/meta/lib/oeqa/selftest/cases/rust.py", line 131, in test_rust
    retval = runCmd(cmd)
  File "/srv/pokybuild/yocto-worker/qemux86-64-tc/build/layers/openembedded-core/meta/lib/oeqa/utils/commands.py", line 214, in runCmd
    raise AssertionError("Command '%s' returned non-zero exit status %d:\n%s" % (command, result.status, exc_output))
AssertionError: Command 'export TARGET_VENDOR="-poky"; export PATH=/srv/pokybuild/yocto-worker/qemux86-64-tc/build/build-st-1700604/tmp/work/x86-64-v3-poky-linux/rust/1.90.0/recipe-sysroot-native/usr/bin/python3-native:/srv/pokybuild/yocto-worker/qemux86-64-tc/build/build-st-1700604/tmp/work/x86-64-v3-poky-linux/rust/1.90.0/recipe-sysroot-native/usr/bin:/srv/pokybuild/yocto-worker/qemux86-64-tc/build/build-st-1700604/tmp/work/x86-64-v3-poky-linux/rust/1.90.0/recipe-sysroot-native/usr/bin/x86_64-poky-linux:/srv/pokybuild/yocto-worker/qemux86-64-tc/build/build-st-1700604/tmp/hosttools:$PATH; export RUST_TARGET_PATH=/srv/pokybuild/yocto-worker/qemux86-64-tc/build/build-st-1700604/tmp/work/x86-64-v3-poky-linux/rust/1.90.0/rust-targets; export RUSTFLAGS='-C strip=debuginfo'; export TEST_DEVICE_ADDR="192.168.7.6:12345"; cd /srv/pokybuild/yocto-worker/qemux86-64-tc/build/build-st-1700604/tmp/work/x86-64-v3-poky-linux/rust/1.90.0/sources/rustc-1.90.0-src; python3 src/bootstrap/bootstrap.py test  --exclude src/bootstrap  --exclude src/doc/rustc  --exclude src/doc/rustdoc  --exclude src/doc/unstable-book  --exclude src/etc/test-float-parse  --exclude src/librustdoc  --exclude src/rustdoc-json-types  --exclude src/tools/coverage-dump  --exclude src/tools/jsondoclint  --exclude src/tools/lint-docs  --exclude src/tools/replace-version-placeholder  --exclude src/tools/rust-analyzer  --exclude src/tools/rustdoc-themes  --exclude src/tools/rust-installer  --exclude src/tools/test-float-parse  --exclude src/tools/suggest-tests  --exclude src/tools/tidy  --exclude tests/assembly-llvm/asm/aarch64-outline-atomics.rs  --exclude tests/codegen-llvm/issues/issue-122805.rs  --exclude tests/codegen-llvm/thread-local.rs  --exclude tests/mir-opt/  --exclude tests/run-make  --exclude tests/run-make-fulldeps  --exclude tests/rustdoc  --exclude tests/rustdoc-json  --exclude tests/rustdoc-js-std  --exclude tests/ui/abi/stack-probes-lto.rs  --exclude tests/ui/abi/stack-probes.rs  --exclude tests/ui/codegen/mismatched-data-layouts.rs  --exclude tests/codegen-llvm/rust-abi-arch-specific-adjustment.rs  --exclude tests/ui/debuginfo/debuginfo-emit-llvm-ir-and-split-debuginfo.rs  --exclude tests/ui/feature-gates/version_check.rs  --exclude tests/ui-fulldeps/  --exclude tests/ui/process/nofile-limit.rs  --exclude tidyselftest --no-doc --no-fail-fast --bless --target x86_64-poky-linux-gnu' returned non-zero exit status 1:
...

https://autobuilder.yoctoproject.org/valkyrie/#/builders/66/builds/2691

Can you have a look at this error?

Thanks,
Mathieu

-- 
Mathieu Dubois-Briand, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com