[FFmpeg-devel] [RFC/HACK] textrel-free x86_64 fft_mmx.asm

Reimar Döffinger Reimar.Doeffinger
Sat Jan 23 23:47:25 CET 2010


On Fri, Jan 22, 2010 at 11:38:40PM +0100, Reimar D?ffinger wrote:
> On Sun, Dec 13, 2009 at 09:59:46PM +0100, Reimar D?ffinger wrote:
> > On Tue, Nov 17, 2009 at 01:10:53AM +0100, Reimar D?ffinger wrote:
> > > On Mon, Nov 16, 2009 at 07:47:44PM +0000, Loren Merritt wrote:
> > > > On Tue, 10 Nov 2009, Reimar D?ffinger wrote:
> > > > 
> > > > > I'm sure it can be made at least a bit less ugly, this is my first
> > > > > attempt at both that kind of thing and yasm.
> > > > 
> > > > fft_call%3%2 is unnecessary. If I thought the patch were a good idea, I 
> > > > would make things relative to start-of-section ($$) instead of another 
> > > > symbol.
> > > 
> > > I admit that is also (besides not knowing about $$) a remnant of when I
> > > didn't know there's no RIP-relative register call.
> > > While I find the patch not that ugly, I understand the scepticism, since
> > > there is no real _need_ for it.
> > 
> > But since the gentoo devs still get complaints about it again and again,
> > could we still consider it anyway?
> 
> This is the official threat to apply...

If even that doesn't make anyone care I have little hope, but still...
Attached are two alternative patches, both get rid of the .section rodata
hack specifically for macho64.
All changes only affect x86_64 systems.
The first is based on the patch posted in this thread before and completely
gets rid of relocations by using RIP-relative addressing, so the array
does no longer need to be in .rodata.
The other one leaves all code unchanged but just changes the condition
so that the address table is in .rodata for all systems that set PIC.
Either gets rid of textrels which is the whole purpose of the effort...
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