[clang] [TBAA] Emit distinct TBAA tags for pointers with different depths,types. (PR #76612)

[Florian Hahn via cfe-commits]

https://github.com/fhahn commented:

> Changes generally LGTM though I think this should come with a release note so users know about the new command line options and functionality?

Thanks, I tried to add release note entries for the new behavior + the new flags. Hope I added them in the right place.

> I don't see any issues with the code. I'd prefer if we has a TYSan-instrumented bootstrap build of LLVM before we merge this, so we're confident this doesn't cause any unexpected issues.

Just updated the tysan branches again. Unfortunately we aren't yet at a point where LLVM is `tysan` clean, there is a large number of reported violations when running the tblgen built with `tysan` even without this patch. I'd expect that a substantial amount of work is still needed to get to a state where we can build LLVM successfully with tysan.

What is feasible at the moment is building SingleSource and for that the patch doesn't add new regressions (there are ~20 tests failing with tysan out of ~1800). Still building MultiSource, but some files take a huge amount of time to build with tysan :(

https://github.com/llvm/llvm-project/pull/76612