[llvm] [BOLT][DebugInfo] Make parallel DWARF debug names generation deterministic(1/2) (PR #197670)

[via llvm-commits]

Thrrreeee wrote:

> Awesome! So it is already tracked. Funny, I used ThreadSafe DWARFContext and couldn't repro anymore the race. But maybe it is still there then. Thanks for linking the PR

The races occurred on lazily-initialized members of the same DWARFUnit object — specifically the DieArray, Abbrev, and other member variables.
Running it under TSan still produces data race warnings, such as follows:

> SUMMARY: ThreadSanitizer: data race /home/jinrui/llvm-pr/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp:1062:8 in llvm::DWARFUnit::getAbbreviations() const
>
> SUMMARY: ThreadSanitizer: data race /home/jinrui/llvm-pr/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp:507:31 in llvm::DWARFUnit::tryExtractDIEsIfNeeded(bool)

But it likely doesn't affect normal functionality？

https://github.com/llvm/llvm-project/pull/197670