[lld] [lld] Add support for .eh_frame_hdr sdata8 (PR #174486)

[Fangrui Song via llvm-commits]

MaskRay wrote:

Thanks for putting this patch together! It’s a great foundation, but I think we need to polish a few areas to ensure it's as robust and clean as possible.

* Range Checks: The d->getVA check should account for the addend, even in cases where it is typically zero.
* We can remove the folded and partition conditions; they currently duplicate isFdeLive and aren't strictly necessary here.
* There is some duplication between updateAllocSize and writeTo. It would be much cleaner to cache the result in updateAllocSize for the write phase to use.
* We should move forward with removing EhFrameSection::getFdePc.

Test suggestions:

* The test only checks out-of-range `eh_frame_ptr`, not out-of-range table entries.
* We should check section content. (Eventually we should add `llvm-readelf --unwind` support and migrate to it)

I’m going to create a revised patch based on your work that addresses these points.


https://github.com/llvm/llvm-project/pull/174486