[PATCH] D96627: [llvm-jitlink] Implement JITLoaderGDB ObjectLinkingLayer plugin for ELF x86-64

[Lang Hames via Phabricator via llvm-commits]

lhames added a comment.

This is very exciting.

This is adopting RuntimeDyld's approach of patching section addresses to inform the debugger about final locations. I think this is ideal for a prototype, but probably not the right approach to the final version. I've only got two loosely formed thoughts on this so far:

(1) We shouldn't special-case the JITLinkContext callbacks except as a last resort. If we have to use them at all we should prefer making any information required available via generic structures like the LinkGraph. In this case I think you could build a SectionRange for each JITLink::Section rather than rely on the SegmentLayout.

(2) If we constructed the debug object file from scratch (rather than mutating the existing one) then we could

- support debug info for raw LinkGraphs (very attractive for long term performance -- avoids serializing / deserializing to objects),
- reduce memory usage by not redundantly representing non-debug sections in the debug object
- potentially dead strip debug info to further reduce memory overhead

Whether any of this is reasonable, and how much would it would be is another question. Probably time for me to learn some DWARF. :)

Dave -- do you have any immediate thoughts?


Repository:
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