[llvm] [llvm-cov] Option to ignore hash mismatches for non-emitted symbols (PR #97574)

[NAKAMURA Takumi via llvm-commits]

chapuni wrote:

I think there is a workaround on Clang side. Let me investigate in this weekend (not the holiday).

* Emit non-zero hash for the empty `CompoundStmt` `{}`
* Calculate hashes for visible `Decl`s. I have to investigate not to be redundant.

IMO, we could implement "non-strict merge", that matches just to the name and number of params.

https://github.com/llvm/llvm-project/pull/97574