[clang] [llvm] [MemProf] Expand optimization scope to internal linakge function (PR #73236)

[Teresa Johnson via cfe-commits]

teresajohnson wrote:

> @lifengxiang1025 thanks for flagging this issue. I think it's best to not rely on unique-internal-linkage-name here. Instead we should extend the logic in RawMemProfReader.cpp to include "filename;" if the function is internal linkage as expected by IRPGOFuncName. Can you try this approach?

I don't think we want to change the name in the frames themselves, as the names in the debug info when matching don't contain this prefix. Although I suppose we could modify the matcher to add the prefixes when matching frames too. I.e. here: https://github.com/llvm/llvm-project/blob/c0fe0719df457b0992606b0f2a235719a5bbfd54/llvm/lib/Transforms/Instrumentation/MemProfiler.cpp#L806

It sounds like the issue is that the names used to index the memprof records do not use the PGOFuncName scheme and therefore we never find any memprof records for an internal linkage function during matching. I.e. the GUID passed to InstrProfWriter::addMemProfRecord. Unfortunately, looking at RawMemProfReader.cpp it does look like that eventually gets populated out of the Function (GUID) field from same Frame setup code. So we'd either need to do some extra handling in that code so that the prefix is only used for the record entry, or change the matcher (the latter may be the easiest).

https://github.com/llvm/llvm-project/pull/73236