Profraw files are not produced when using instrument-coverage on freebsd

[elinorbgr]

Running the following command on the calloop repo on a FreeBSD environment:

env LLVM_PROFILE_FILE="calloop-%p-%m.profraw" RUSTFLAGS="-Cinstrument-coverage" cargo +nightly test --all-features

No .profraw file is produced with the latest nightly (which now causes our CI script to fail).

Meta

The files were correctly produced with rustc 1.60.0-nightly (88fb06a1f 2022-02-05), but are no longer produced on rustc 1.60.0-nightly (30b3f35c4 2022-02-17) nor rustc 1.61.0-nightly (10913c000 2022-03-03). This fails on both FreeBSD 13.0 and FreeBSD 12.1 (according to our CI).

Running the command on Linux using rustc 1.61.0-nightly (10913c000 2022-03-03) works as expected, producing the .profraw files.

[nagisa]

For this to be really actionable, it would be great if you could reduce the regression range further. E.g. using https://github.com/rust-lang/cargo-bisect-rustc.

cc #79121

[elinorbgr]

As a first range reduction, I can say that rustc 1.60.0-nightly (30b3f35c4 2022-02-17) is actually the first nightly to have the problem, the previous one rustc 1.60.0-nightly (75d9a0ae2 2022-02-16) works fine.

Looking at the associated commit range, an obvious suspect is 30b3f35, which merges #93577, upgrading to LLVM 14. I'll see if I manage to confirm this using cargo-bisect-rustc

[elinorbgr]

I confirm that the issue was introduced by 30b3f35.

[asomers]

@elinorbgr I can no longer reproduce this bug using Rust 1.73.0-nightly and a recent build of FreeBSD 14.

[elinorbgr]

Indeed, it seems to work now! Thanks for the ping!