Re: predep_objects & postdep_objects with Intel 8.1

[Gary Kumfert]

On Fri, 17 Dec 2004, Ralf Wildenhues wrote:

> [ slightly reordered ]
>
> * Gary Kumfert wrote on Fri, Dec 17, 2004 at 12:17:17AM CET:
> > On Thu, 16 Dec 2004, Gary Kumfert wrote:
> > >
> > > I'm tracking down an issue between Intel 8.1 and libtool 1.5.10.
> > > It seems that libtool adds and crtbeginS.o crtendS.o files to
> > > the link line for shared libraries... then icpc does the same..
> > > then ld complains about multiply defined symbols!  Eeek!
>
> Wait..
>
> > > Shouldn't libtool (or libtool.m4) detect these object files
> > > already appear in the link line and not add them directly?
>
> hmm
>
> > > Interestingly libtool (correctly) does not insert crtbeginS.o and
> > > crtendS.o into shared library link lines with icc or ifort.
> > > Why icpc?
>
> hmm.  What does
> $ ./libtool --config | grep with_gcc
> say?
>
> > > Here's some of the differences in what Intel 7.0, 8.0, and 8.1
> > > pass to ld.  Note that the differences between 8.0 and 8.1 seem
> > > to be significant!  In particular 8.1 seems to use GNU's crtbeginS.o and
> > > crtendS.o.   7.0 & 8.0 seems to rely on intel's crtxi.o and crtxn.o files
> > > instead.
>
> I believe it's even more complicated than that.  It might also depend on
> how ICC was installed -- whether to its provided or GNU libstdc++, and
> whether the latter was found by ICC at installation time (maybe that's
> what you are seeing).
>
> I haven't had a chance to look how Libtool fares with all of this.
> (BTW, multi-file interprocedural optimization and template libraries
> provide more opportunity for failure, feel free to go wild if you have
> time to look at this and cure possible problems.  :-)
>
> > > I admit that I don't really understand what low-level linker trickery
> > > these files accomplish.  (A pointer to some literature would be helpful.)
>
> Runtime initialization and termination for the library/program given.
> No, I can't give you a good answer on this, but there are bits of
> information to be found in the gcc and ld manuals (info files), and
> http://en.tldp.org/HOWTO/Program-Library-HOWTO/miscellaneous.html#INIT-AND-CLEANUP
> http://docs.sun.com/app/docs/doc/817-1984/6mhm7pl17?a=view
> and links therein are quite informative.  If you'd like to see how complicate
> this stuff can get, browsing around
> http://www.lnf.infn.it/computing/doc/aixcxx/html/complink/concepts/cushrlib.htm
> is fun.
>
> > I think I found the problem.  When I upgraded with libtoolize.
> > "libtoolize -f -c" it copied things like config.guess, config.sub,
> > and ltmain.sh correctly into my AC_CONFIG_AUX_DIR.
> >
> > But, it did *not* update my libtool.m4 in AC_CONFIG_MACRO_DIR.
> > After copying by hand, I saw that indeed the version of icpc is
> > checked and different flags are selected.
>
> Does that mean all your other problems above are gone now?
> I haven't looked at them yet because of this statement.
>

This problem is resolved, I think.  But I've got a much bigger one
I'll put in a separate post.

Thanks,

Gary

> > Wasn't libtoolize supposed to update the libtool.m4 file?
>
> I'll leave this question for somebody else to answer.
>
> Regards,
> Ralf
>