Re: [commit/AIX] Fix error when loading core file

[Pedro Alves <pedro_alves@portugalmail.pt>]

Ulrich Weigand wrote:
> Joel Brobecker wrote:
> 
>> I think the problem started when we introduced post_create_inferior.
>> This causes us to call the SOLIB_CREATE_INFERIOR_HOOK, which in our
>> case is defined as a call to xcoff_relocate_symtab. I haven't really
>> checked with older versions of GDB because rebuilding GDB on AIX is
>> mighty slow, but it very much looks like this function was not called
>> in the case of core files before. This function is assuming a live process,
>> not a core file. So what I did was do an early return when debugging
>> a core file.
> 
> Yes, if you look at the SOLIB_ADD definition:
> 
> #define SOLIB_ADD(a, b, c, d)   \
>   if (PIDGET (inferior_ptid))   \
>     /* Attach to process.  */  \
>     xcoff_relocate_symtab (PIDGET (inferior_ptid)); \
>   else          \
>     /* Core file.  */ \
>     xcoff_relocate_core (c);
> 
> it is clear that the _symtab version is intended to be called only
> in the case of live process.
> 
> It looks like something changed to get SOLIB_CREATE_INFERIOR_HOOK
> now invoked as well ...
> 
> 
>> What this made me realize, however, is that we should really be
>> converting the AIX port to using the target_so_ops. I'll try to do
>> that soon. In the meantime, the attached patch should be good enough.
> 
> Yes, I noticed that as well.  I had already started to do that, but
> got side-tracked by other stuff in the meantime.  One problem is that
> the ldinfo ptrace call that is required to get at the list of loaded
> shared libraries is really a native-only call.
> 
> I'd thought of defining a TARGET_OBJECT_LDINFO xfer_partial object
> that reflects the contents of the ldinfo, and use this in the
> implementation of a (platform-independent) solib-aix.c file.
> The rs6000 native target and the core file support would need to
> be extended to supply that object.
> 

If AIX needs to use native calls to get at the shared libraries list,
perhaps you could also look if the solib-target.c Daniel is pushing
for remote dll support, and see if it would be a good fit for AIX too.
As a quick look it seems so.  You would move aix_current_sos
to the target_ops, and perhaps needs a few other tweaks 
(aix_in_dynsym_resolve_code, and aix_solib_create_inferior_hook).
Although he presented it as remote support, it also makes sense
for native win32 debugging, so it may also make sense as native
AIX debugging.

You would need these applied:
http://sourceware.org/ml/gdb-patches/2007-05/msg00140.html
http://sourceware.org/ml/gdb-patches/2007-05/msg00145.html

Cheers,
Pedro Alves