[PATCH] D63409: [RISCV] Specify various encodings for DWARF exception handling

Tue Jul 16 05:02:29 PDT 2019

asb added a comment.

In D63409#1587351 <https://reviews.llvm.org/D63409#1587351>, @edward-jones wrote:

> In D63409#1587117 <https://reviews.llvm.org/D63409#1587117>, @asb wrote:
>
> > Hi Ed, this is really hard to review without any documentation in the psABI or otherwise. Can you confirm that you've verified this matches gcc/gas? Are you planning to submit document to riscv-elf-psabi-doc to reflect this?
>
>
> I've opened a pull request on the psABI docs (https://github.com/riscv/riscv-elf-psabi-doc/pull/110). I'm not entirely sure the details here are relevant to the ABI though. As far as I'm aware provided the individual CIE and FDEs are well-formed it shouldn't matter if the encodings differ from those specified in other CIE and FDEs.
>
> On another note, after taking a look at the GCC code for this I'm not convinced the non-PIC values for the encodings match. GCC appears to just encode everything as pc-relative sdata4, whereas the above encodes things as absolute when PIC is not specified.

Yes, I was trying to cross-reference to what GCC does and couldn't see a match for everything you specify here.

Many thanks for submitting that PR, as you say it's not clear where it belongs but it's certainly useful to have it written down somewhere!

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