[llvm] [DWARFVerifier] Allow overlapping ranges for ICF-merged functions (PR #117952)

[via llvm-commits]

alx32 wrote:

> What about subranges that overlap? If someone was using something like Propeller where a function ends up split into multiple sections, then those sections are ICF'd? (I'm not 100% sure that's possible, but it seems quite plausible to me... )

You are correct that theoretically it's possible to have overlapping address ranges merged by something like ICF. But I think the default behavior for tooling has been to not have overlapping address ranges in dSYM's. We changed this with adding `--keep-icf-stabs` in LLD where such behavior is permitted. This change is designed to pair up with the current behavior of `--keep-icf-stabs`.

I could add the behavior to check for overlapping subranges, but I wouldn't be able to generate a test case for it as I don't think it's currently possible to generate overlapping subranges (we would need something like `--keep-icf-stabs` for Propeller). 

Any advice on how to generate a valid scenario for the overlapping subranges case or ideas how to proceed ?

https://github.com/llvm/llvm-project/pull/117952