[PATCH] 32-bit PowerPC ELF Position Independent Code

[Bill Schmidt]

On Wed, 2014-07-16 at 07:10 -0500, Bill Schmidt wrote:
> Hi Justin,
> 
> On Tue, 2014-07-15 at 22:36 -0700, Justin Hibbits wrote:
> 
> > Thanks for reviewing the code.  I think I've addressed all your
> > comments, including adding a few rudimentary tests for it.  I've
> > attached the most recent patch for review.  I hope this can get in
> > before the 3.5 branch, so will also be looking for somebody with
> > commit privileges to do the honors.
> 
> Thanks for the changes.  You did address all the changes but one:  I'm
> still unsure why you are using .got2 rather than .got.  Can you please
> explain?  In the end it's no skin off my back if you want to keep the
> redundant PLT stubs, as I don't have any investment in 32-bit
> efficiency; so this isn't a showstopper for me, but others may care.
> This may be the right thing for you, but it would be good to understand
> why.

Justin had actually clarified this in IRC overnight, but I didn't see
the message until now.  He uses .got2 because this is what he sees from
GCC.  Justin, this is a fine reason, but I suggest that you follow up
with Alan Modra to see whether GCC always uses this or whether this
behavior depends on any options.  This is no reason to hold up the
patch, though.

Thanks,
Bill

> 
> The tests are a good start.  You should also have a test that
> demonstrates the use of R30 as GOT base when accessing a global, and a
> test that demonstrates the use of R29 as the base register when needed.
> There are probably existing tests that you can modify for these
> purposes, though I can't point to them offhand.
> 
> I'm constrained by company policy from committing patches on behalf of
> others except in urgent circumstances, so I hope one of the other
> PPC32-interested folks will be willing to step up here once the patch is
> complete.
> 
> Thanks,
> Bill
> 
> > 
> > Thanks,
> > Justin
> 
> 
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