[PATCH] Skip MachO scattered relocations in RuntimeDyld.

Lang Hames lhames at gmail.com
Thu Aug 8 18:14:25 PDT 2013


Thanks very much for the review guys. Committed in r188044.

I'm working on support for scattered relocations now - that will allow me
to drop the hacky part of r188044, and instead have fine-grained detection
of when it's safe to ignore these relocations. I hope to have a patch ready
for review tomorrow.

- Lang.


On Thu, Aug 8, 2013 at 5:30 PM, Kaylor, Andrew <andrew.kaylor at intel.com>wrote:

>  Agreed on all counts.****
>
> ** **
>
> *From:* Jim Grosbach [mailto:grosbach at apple.com]
> *Sent:* Thursday, August 08, 2013 4:30 PM
> *To:* Lang Hames
> *Cc:* Commit Messages and Patches for LLVM; Kaylor, Andrew
> *Subject:* Re: [PATCH] Skip MachO scattered relocations in RuntimeDyld.***
> *
>
> ** **
>
> Hi Lang,****
>
> ** **
>
> I agree this is fine to do, but the comment could use a bit more
> explanation of why it’s right to keep going rather than bail out like we do
> on other unhanded relocations. Adding a FIXME for any cases which actually
> will require applying the relocation at runtime rather than just using the
> pre-computed value would be good, too.****
>
> ** **
>
> With that change, this LGTM.****
>
> ** **
>
> -Jim****
>
> ** **
>
> On Aug 8, 2013, at 12:36 PM, Lang Hames <lhames at gmail.com> wrote:****
>
>
>
> ****
>
> Aaand I forgot to attach the patch. Here it is.****
>
> ** **
>
> - Lang.****
>
> ** **
>
> On Thu, Aug 8, 2013 at 12:35 PM, Lang Hames <lhames at gmail.com> wrote:****
>
> Hi All,****
>
> ** **
>
> At the moment a scattered relocations will cause llvm-rtdyld to go off
> into the weeds and eventually assert while trying to look up a section that
> doesn't exist.****
>
> ** **
>
> Eventually we want to handle these relocations, but in practice they often
> aren't required. For example, section differences only matter if symbols
> are moved relative to one another, which RuntimeDyld doesn't do.****
>
> ** **
>
> This patch skips scattered relocations, which will unbreak some simple
> llvm-rtdyld use-cases while I work on proper support.****
>
> ** **
>
> Cheers,****
>
> Lang.****
>
> ** **
>
>
> <skip_scattered_relocations.patch>_______________________________________________
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> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits****
>
> ** **
>
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