Re: Possible weak linker bug in ld

[Alan Modra <amodra at bigpond dot net dot au>]

On Wed, Oct 15, 2003 at 05:16:22PM +0200, Svein E. Seldal wrote:
> Alan Modra wrote:
> 
> >On Wed, Oct 15, 2003 at 02:39:58PM +0200, Svein E. Seldal wrote:
> >
> >>I think I run across a bug in ld when linking files with weak symbols. 
> >
> >
> >See http://www.caldera.com/developers/gabi/latest/ch4.symtab.html
> >
> >"When the link editor searches archive libraries [see ``Archive File''
> >in Chapter 7], it extracts archive members that contain definitions of
> >undefined global symbols. The member's definition may be either a global
> >or a weak symbol. **The link editor does not extract archive members to
> >resolve undefined weak symbols.** Unresolved weak symbols have a zero
> >value."
> 
> May I ask why not?

That's the historical way.  I believe the sunos ELF linker behaved like
this.

> I respect this policy if there's a reason behind it. But, if there's 
> none, I would suggest that we alter this behavior to be able to seach 
> libs for strong symbol overrides, please.

We certainly can't do this by default, as I can easily imagine cases
that depend on the old behaviour.  Would you like to add a linker
switch to extract archive members to satisfy undefined weak syms?  A
small change to elflink.h:elf_link_add_archive_symbols should do
what you want.

-- 
Alan Modra
IBM OzLabs - Linux Technology Centre