[U-Boot] [PATCH] mpc83xx: Add -fpic relocation support

[Joakim Tjernlund]

Albert ARIBAUD <albert.aribaud at free.fr> wrote on 2010/10/13 11:05:09:
> 
> Le 13/10/2010 09:07, Joakim Tjernlund a écrit :
> 
> > Did you use -msingle-pic-base too with -fpic/-fPIC? This is what makes
> > a difference(together with -fpic). The most interesting size is
> > the total flash size IMHO. Reducing insn's in RAM at the expense
> > of flash is not what most users need I think.
> 
> Yes, I did use -msingle-pic-base -- actually, I am the one who submitted 

> the patch for ARM to that effect, precisely after all my tests :) -- but 

> the code growth I am talking about is accesses, not setup.

Ah, that was you. That patch made me look at adding -msingle-pic-base to 
ppc :)

> 
> >> This simply implies that -fPIC is a better choice for PPC (and hence
> >> -mrelocatable) while -fpie is a better one for ARM.
> >
> > -fPIC isn't optimal(it is bigger) but until my gcc patch gets into
> > gcc one cannot use -fpic(it gets promoted to -fPIC by gcc).
> > -fpic is smaller but one cannot build apps has has a GOT over 32KB 
with
> > that
> 
> You get a GOT over 32 KiB? IIRC, the reloc tables for ARM with -pie are 
> slightly below 19 KiB for a typical u-boot; I'm surprised that a GOT 
> would go bigger than the ELF table for the same work.

No, -fpic can handle 32KiB, if it gets bigger you have to use -fPIC.
My board uses about 7.5 KiB GOT+fixups

    Jocke