AIX 5.1 dlopen shared library exception handling problem

[Joerg.Richter@pdv-FS.de]

>	According to an analysis in a related bug report, it appears that
> GCC's assumption about the sorting of FDEs is getting confused by the
> address ranges of shared libraries used by AIX.  The duplicate symbols
> cause FDEs for the same symbol to appear in multiple shared libraries.

Please note that this are two different issues. Duplicate symbols in user
code can cause uncaught exceptions. But only when they are both the first
definition in both translation units. I think GCC uses their name to name
the unwind table or something related. So the unwind information for one
translation unit is lost.

I tried to describe the second cause for uncaught exceptions in bug report
13878. There are no duplicate symbols (in user code) involved. All unwind
information is still present. But due to the fact that some fdes are shared
between shared libraries GCC runtime doesn't find the right fde. 

The patch in PR13878 fixes the second issue. Not the first.


   Joerg