GCNO files contain path which are neither absolute nor relative

[calixteman]

When profiling this code:

fn main() {
    println!("hello");
}

the generated gcno contains the following paths:

llvm-cov-7 gcov -dump plop-12b91b0bdcb3e9a4.gcno 2>1 | rg 'File .*/'
1:File 'libcore/fmt/mod.rs'
5:File 'libcore/ops/function.rs'
9:File 'libcore/ptr.rs'
13:File 'libstd/process.rs'
17:File 'libstd/rt.rs'
21:File 'libstd/sys/unix/process/process_common.rs'
25:File 'src/main.rs'

The 6 first paths are neither absolute nor relative.
So it's pretty hard to do something with them.

[marco-c]

The tracking issue for -Zprofile is #42524.

[Enselic]

Triage: Looks like this is fixed now? I get this:

$ rustc -Zprofile -Cdebuginfo=2 main.rs
$ llvm-cov-14 gcov -dump main.gcno 2>&1 | grep File
File '/rustc/a57770440f1ebe5b992551d3bcc489ae211908d4/library/std/src/sys_common/backtrace.rs'
File '/rustc/a57770440f1ebe5b992551d3bcc489ae211908d4/library/std/src/rt.rs'
File '/rustc/a57770440f1ebe5b992551d3bcc489ae211908d4/library/core/src/fmt/mod.rs'
File '/rustc/a57770440f1ebe5b992551d3bcc489ae211908d4/library/core/src/ops/function.rs'
File '/rustc/a57770440f1ebe5b992551d3bcc489ae211908d4/library/core/src/ptr/mod.rs'
File '/rustc/a57770440f1ebe5b992551d3bcc489ae211908d4/library/std/src/process.rs'
File 'src/main.rs'

[Enselic]

Triage: It would be good to use cargo bisect-rustc to find the fix and make sure a regression test was added.

[workingjubilee]

this is about gcov-based profiling, which we now no longer support.