[PATCH] D111863: [libunwind] Add an interface for dynamic .eh_frame registration

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lhames added a comment.

In D111863#3071353 <https://reviews.llvm.org/D111863#3071353>, @joerg wrote:

> I would strongly prefer if ORCv2 doesn't depend on this. It essentially forces libunwind to parse the whole section just to find the delimiters of the FDEs. That's a lot of unnecessary work as JIT use normally allows registering functions individually.

I don't follow this. Does libunwind provide some way to register FDEs without parsing the FDE content? If so we can definitely use that, but we should still process the whole section: ORC links objects (not functions), and we should register every FDE for an object when it's linked in.

It's also worth noting that ORC and MCJIT have always called `__register_frame` on every frame, which seems like it should be at least as much work as this.


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https://reviews.llvm.org/D111863