Re: Symbol-based dependencies on shared libraries: some news
On Sun, Aug 05, 2007 at 05:11:53PM +0200, Raphael Hertzog wrote:
> On Sat, 04 Aug 2007, Steve Langasek wrote:
> > On Sat, Aug 04, 2007 at 10:41:25PM +0200, Raphael Hertzog wrote:
> > > On Sat, 04 Aug 2007, Loïc Minier wrote:
> > > > Do you strip the "well known symbols" you've seen on each arch so that
> > > > one only has to specify the other symbols?
> > > No, because they might change with the toolchain and we want to track that
> > > properly...
> > Why does it need tracking? If these symbols were to disappear that would
> > be no loss, it shouldn't be relevant to the library ABIs at all. I think it
> > would indeed be better to exclude these symbols from the list.
> Somehow I always thought that the executables were using those symbols.
> If that's not the case, and if they are only used by the internal
> machinery (i.e. none of those symbols actually appear undefined in objdump's
> output of a program), then I'll happily strip them from the symbols file.
Yes, they are symbols that are not referenced by other objects. In fact, I
believe you'll find in the case of each of these symbols that *every* binary
on the given architecture includes their own copy of these symbols,
including executables as well as libraries.
> That exclude list will still have to be maintained over the years I think
> since the list will probably evolve.
Hopefully it will evolve with negative magnitude, so we get fewer such
symbols over the years rather than more of them. :) I've seen other people
opine before, and I agree, that these extra exported symbols ought to be
considered bugs in the toolchain, and ought to eventually be removed from
the export list.
> I'm checking for example on a powerpc machine:
[...]
> So it looks like those symbols are defined in each and every binary.
> But the programs do not rely on the same symbols from the libraries.
> Thus it seems fine to exclude them from the symbols files.
Yep.
Cheers,
--
Steve Langasek Give me a lever long enough and a Free OS
Debian Developer to set it on, and I can move the world.
vorlon@debian.org http://www.debian.org/
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