[llvm] [TySan] Add initial Type Sanitizer (LLVM) (PR #76259)

[Arthur Eubanks via llvm-commits]

aeubanks wrote:

could we get a quick writeup of how TySan works in `llvm/docs`?

also, is there a reason to have both a module and a function pass instead of just a module pass?

https://github.com/llvm/llvm-project/pull/76259