LLVM_PROFILE_FILE env override flag

[notdanhan]

Hey I'm working on a pretty big C++ project and we're doing some performance testing for due diligence and I was wondering if there's a flag that you can set that hardcodes the .profraw file name for a given executable

I thought -fprofile-instrument-path would have worked but it didn't

I've got a really weird constraint where the program is launched by a daemon process and somewhere somehow the LLVM_PROFILE_FILE env var gets overwritten and the application it launches ends up not generating any .profraw stuff whatsoever

If the feature does not exist, I would be happy to implement it :)

However if it does, and I failed to properly apply RTFM to my work, that would be pretty great too!

Thanks in Advance

[redraincatching]

i'm also working on this project, and we've tried attempting to bypass the environment variable with

extern "C"
{
void __llvm_profile_set_filename(char *);
}

// ...later
int main(int argc, char ** argv)
{
    __llvm_profile_set_filename(std::format("/tmp/profiling/{}%c.profraw",argv[0]).c_str());
}

however that didn't seem to make a difference. this was set in our process launcher that spawns a load of other threads, in case that might affect behaviour