[PATCH] D78778: [AMDGPU] Add SupportsDebugUnwindInformation to MCAsmInfo

[Scott Linder via Phabricator via llvm-commits]

scott.linder added a comment.

In D78778#2447314 <https://reviews.llvm.org/D78778#2447314>, @dblaikie wrote:

> Sorry, I wasn't really able to follow that description. I'll try to clarify/rephrase my question which might help:
>
> Under some conditions, eh_frame is generated even under -fno-exceptions, right? And you'd like debug_frame to be generated instead/as well, in that case? I'm trying to understand why the generation of these two things (eh_frame/debug_frame) isn't close enough together as to make the fix for this issue be a single conditional somewhere, that picks whether which name to use (& some associated properties, like whether it's ALLOC).
>
> Could you explain the codepath that generates eh_frame under basically the conditions you would like, and why that codepath can't handle being modified to generate debug_frame instead?

No worries, I think I got a little bit ahead of myself :^) I summarized the whole answer to the question you actually asked with " I started by just making changes to DwarfCFIException/DwarfCFIExceptionBase/EHStreamer..."

I started writing up a response describing the code path for the unwind emission and decided it would be easier to just draft a version of the commit without the separate streamer. Part of what I was trying to describe in earlier comments was that I had originally done this, but found that it only made already-complicated code more complicated. In implementing it again I don't know what specifically I didn't like about it before, though.

Let me know what you think of this iteration; I don't know how to localize it much more than this, as the `DwarfCFI` streamer needs to be created and we need to note that the CFI is for debug use only in `AsmPrinter.cpp`. The logical "one condition" that needs to change is `shouldEmitCFI` in `DwarfCFIException.cpp`.


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