15976 2025-09-18 05:55:09 +0000 Rust cc crate mixes host flags with target flags 2026-05-28 14:03:02 +0000 1 1 7 Build System, Metadata & Runtime OE-Core devtools / tool chain unspecified All Multiple NEW Medium normal 6.1 M2 1 skandigraun deepesh.varatharajan ccasciato meta.mr.watcher meta.watcher randy.macleod ross.burton sundeep.kokkonda --- --- Don't know oldest_to_newest 102791 0 skandigraun 2025-09-18 05:55:09 +0000 A recent update in the cc crate has changed the way C/C++ compiler flags are gathered, it now reads more environment variables than it used to: https://github.com/rust-lang/cc-rs/pull/1401 This now sometimes leads to incorrect results. I have noticed this during a recent Firefox update, which also brought the update of the cc crate: in case the recipe is compiled for the target, but a crate has a build-only dependency on another crate, then the used compiler flags look wrong. Build-only dependencies are compiled for the build-host (which is correct), but the crate reads both the CFLAGS/CXXFLAGS and HOST_CFLAGS/HOST_CXXFLAGS variables (the latter ones are defined by cargo_common.bbclass). However the former variables contain flags for the target, and the latter flags contain flags for the build host - and after mixing them, the result can be surprising. Upstream has a bug tracking this also: https://github.com/rust-lang/cc-rs/issues/1469 102795 1 randy.macleod 2025-09-18 14:37:05 +0000 Certain environment variables are passed through to the bitbake system. We need more info on what happened here and then to decide if we can prevent it. 103745 2 randy.macleod 2026-01-07 19:37:43 +0000 Move to 6.0. Gyorgy, do you happen to have a simple reproducer or a suggestion about how we could produce one? 103747 3 5168 skandigraun 2026-01-07 20:32:39 +0000 Created attachment 5168 cc-rs-test.tar.gz The easiest reproduction is to have a Cargo.toml that marks a crate as a build-only dependency - that crate will be compiled with wrong flags (when cross-compiling). This happens with Firefox and Rust also. (But I gotta admit, both are pretty big for testing this). I have attached a simple repro. This is a hello world, with a build-dependency that uses cc-rs - the dependency itself is irrelevant. To see the problem, before compiling set two environment variables: export HOST_CFLAGS=THIS_SHOULD_NOT_APPEAR_ALONG_WITH_CFLAGS export CFLAGS=THIS_SHOULD_NOT_APPEAR_WHEN_COMPILING_RING CC_ENABLE_DEBUG_OUTPUT=1 cargo build -vv Of course both variables are bogus, but they shouldn't be used together in the same compilation command - and the error you will get will show however that they are used in the same compilation command, when compiling ring crate for the host. 5168 2026-01-07 20:32:39 +0000 2026-01-07 20:34:55 +0000 cc-rs-test.tar.gz cc-rs-test.tar.gz application/gzip 452 skandigraun H4sIAAAAAAAAA+3WUWvbMBAAYD/rV1w9GCk0riRbMTT0Yeyl73sMYaiy6og6cpCUjTD23ydnaZq0 27KCk1J6HwFj+UAO5ztddqnU0Plh0D5cJsdBo1KI7spKQTdXtl7fSJhgvBQFFSzGMc5HIgFxpPfZ s/RBOoCkXi2d+UfcoedvVLab/9ulaarM+Z736BI8Koq/5p/l+Tb/NOcx/3nJWQK05/f4o3ee/zsL c2ns4Bx+EIiWXoMztr66qkwdv4nxerXRAb7CNfxee3g2+Phw/+XmExejC7hNZ7pp2vR8TH6S1/5r 6D/s1f9n6eo2C+286XWPQ/XP49mwrX+ax/ovOC2x/k9hspDqXtZ6Sqyc61ji6eP3kJJv2nnT2m6Z ZiyjKdGVCZsVTnmREjJZnxrDSi+0rbRVRvsp+QBhZjzEnwQnbdXOYRuwuoDvM6NmXa/xoBQoJ4MG GcOD3wkjXR/abF1mjKfYUfq3V//eqWPMgC+Z/1gx6s5/Kgqc/07hWf67aaDnEfBQ/6e7/V+s+39e 5Nj/T+Hp/LeITTc09myQ3nSTXGzVrWuqM5zoEEIIIYQQQgghhBBCCCGE3ohfWBYsnwAoAAA=