x32 psABI draft version 0.2

[Jakub Jelinek]

On Thu, Feb 17, 2011 at 04:44:53PM +0100, Jan Hubicka wrote:
> > > According to Mozilla folks however REL+RELA scheme used by EABI leads
> > > to significandly smaller libxul.so size
> > >
> > > According to http://glandium.org/blog/?p=1177 the difference is about 4-5MB
> > > (out of approximately 20-30MB shared lib)
> > 
> > This is orthogonal to x32 psABI.
> 
> Understood.  I am just pointing out that x86-64 Mozilla suffers from startup
> problems (extra 5MB of disk read needed) compared to both x86 and ARM EABI
> because x86-64 ABI is RELA only. If x86-64 ABI was REL+RELA like EABI is, we
> would not have this problem here.

libxul.so has < 200000 relocs, so 5MB is total size of .rela section in
64-bit ELF, you don't magically save those 5MB by using REL.  You save
just 1.5MB.  And for x32 we'd be talking about 2.5MB for RELA vs. 1.6MB for
REL.  There might be better ways how to get the numbers down.

	Jakub