Re: libstdc++/4260: ABI change beween 3.0 and 3.0.1

["John David Anglin" <dave at hiauly1 dot hia dot nrc dot ca>]

> On Mon, Mar 11, 2002 at 05:02:57PM -0500, John David Anglin wrote:
> > > You wrote in the audit trail for this PR that this is now okay.  Can we
> > > close the PR?
> > 
> > Was any code changed to keep the library internal name and global
> > constructors for the library consistent?
> 
> libstdc++ doesn't have any control over the global constructors.  Somebody in
> compiler-land will have to make changes to collect2 to do this.

Looking at the libtool command to build the library in my latest build,
I see "-version-info 4:0:0".  The generated internal name for the library
is "-Wl,+h -Wl,libstdc++.sl.4".  However, the global constructors are:

_GLOBAL__FI_libstdc___sl_4_0

I don't fully understand how the global constructor names are generated
but it is clear that there is a mismatch between the library internal
name and the global constructor symbols.

In the original report, a change in version from 3.0 to 3.0.1 caused
a change in constructor symbol from

_GLOBAL__FI_libstdc___sl_3_0

to

_GLOBAL__FI_libstdc___sl_3_1

If the libraries were intended to be compatible, the constructor symbol
shouldn't have changed.  If not, the library internal name should have
changed to match.  Libtool probably needs to add another digit to the
internal names that it generates for the PA som linker so that its
precision matches that generated by collect2.  However, it also looks
like collect2 isn't generating global constructor names correctly.

Thus, I don't believe the problem is resolved and we will have the same
problem again when there is a minor version change.

Dave
-- 
J. David Anglin                                  dave.anglin@nrc.ca
National Research Council of Canada              (613) 990-0752 (FAX: 952-6605)