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

[Joakim Tjernlund]

Albert ARIBAUD <albert.aribaud at free.fr> wrote on 2010/10/13 08:30:33:
> 
> Le 12/10/2010 23:00, Joakim Tjernlund a écrit :
> 
> > Yes, but the difference isn't really the arch. It is the -mrelocatable
> > flag that is the big difference.
> 
> Not only: obviously, implementing GOT relocation is not done the same on 

> both archs, and it simply is not beneficial on ARM wrt PPC in terms of 
> instructions. I did a pretty extensive run of tests with and without 
> -fPIC and -fPIE on ARM, and GOT relocation clearly makes code bigger, 
> whereas it does not PPC.

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.

> 
> 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