Questions on how to implement native core file support

[Joel Brobecker <brobecker@adacore.com>]

Hello,

While looking at expunging REGISTER_U_ADDR from our documentation
(no longer used), I found out that the documentation about how to
provide core file support is out of date (core-aout has been deleted
a year ago).

Having never written support for core file reading, I have tried
to figure out how to add it.  As far as I can tell, I can see
two forms of core file support:

  1. Native core file support
  2. gdbarch core file support

In the second case, it appears that all you have to do is define
the gdbarch_regset_from_core_section method for your architecture,
and I would guess that this is the prefered method.  However, may
not be always doable, in particular if you depend on certain 
system headers... Any other possible reason?

In the first case, it looks like core_low is relying on
a struct core_fns which is provides pointers to various
target-dependent routines. The thing is, the routine I see
in order to register a particular instance is marked as
deprecated:

    extern void deprecated_add_core_fns (struct core_fns *cf);

Does it mean that, as of today, we only consider the second
gdbarch-based approach? If that's the case, then should we simply
update the documentation to either remove the "Native core file Support"
section, or replace it with a link to gdbarch_regset_from_core_section?

-- 
Joel