Linker Bug or Design Intent (Absolute symbols in zero sized sections)

Alan Modra amodra@bigpond.net.au
Fri Oct 13 11:26:00 GMT 2006


On Thu, Oct 12, 2006 at 10:34:09AM -0400, Jakub Jelinek wrote:
> On Thu, Oct 12, 2006 at 01:13:41PM +0930, Alan Modra wrote:
> > > Against emitting empty sections speaks both that it is a wasted space
> > > in section header table/.shstrtab, but more importantly that empty
> > > sections are an endless source of bugs
> > 
> > Agreed.
> > 
> > If we are to remove them, then 
> > a) Detecting a symbol assignment in a linker script should result in the
> >    section alignment and vma being honoured.
> 
> Not sure what are we doing ATM here.

The wrong thing..

> > b) All the ELF backends will need changes so that removed output section
> >    syms are never used when emitting relocs.  At the same time, we may
> >    as well just use one section sym for all relocs (or two for targets
> >    that might want to relocate the data segment separately from the text
> >    segment).
> 
> Sure.
> 
> > c) _bfd_fix_excluded_sec_syms should be changed to not create absolute
> >    syms.
> 
> And instead have the nearest section in the same loadable segment in
> st_shndx?

Something like that.  I figured on just using the closest preceding
section.  BTW, I started throwing a patch together to do (b).

-- 
Alan Modra
IBM OzLabs - Linux Technology Centre



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