LLVM 20 profdata function entry coverage

[xd009642]

Currently fails

[jyn514]

👋 i'm interested in working on this -- i see that the format is documented in https://llvm.org/docs/InstrProfileFormat.html#indexed-profile-format and that profdata is parsed in instrumentation_profile::indexed_profile::parse_summary. is there anything else i should look at before i get started? probably i can dig up an LLVM changelog showing the differences between LLVM 20 and earlier versions somewhere.

[xd009642]

No that's probably about it. If you look at the llvm repo and the relevant tag, go to llvm/test/tools/llvm-profdata/Inputs there might be some .profdata files I removed because they didn't parse. If you add those back in to the relevant test folder it should help make sure things match.

There might also be some stuff in one of my CLI helpers where you can add a new arg to display that coverage info and diff against the LLVM tools (potentially hard, I stopped doing that for things I didn't care about because compatability is a bit of a faff)