Re: [Ada/dwarf] New DW_AT_GNAT_descriptive_type DWARF attribute...

[Tom Tromey <tromey at redhat dot com>]

>>>>> "Joel" == Joel Brobecker <brobecker@adacore.com> writes:

Joel>   1. Detection of the use of this attribute: Right now, the FSF GCC
Joel>      does not produce this attribute, so we need to be able to
Joel>      detect when the attribute is in use and when it's not.

[...]

Joel>      The way AdaCore did it was through a special keyword in
Joel>      the DW_AT_producer CU attribute.

We talked about this a bit on irc.  IIUC the reason that some flag is
needed is that a given type may or may not have a parallel type, and
the searches are expensive.

Joel>    2. The dreaded gnat_stuff addition to the type_specific area
Joel>       in struct main_type. Pretty kludgy, borderlining on gross :-).

We talked about this too.  main_type has a bunch of extra bits; a
couple can be taken for the discriminant.  This should clear up the
gross parts here.

Joel> What I'd like to do, however, is get a consensus on whether we're OK
Joel> with supporting this attribute, and how GCC is supposed to tell GDB
Joel> that the attribute is being used.  That way, we can start on the GCC
Joel> end as well.

I think it is important to note that you already have the GCC work
done, just not in the FSF GCC.  If you were starting from scratch, I
would much prefer a DWARF-based solution.

Given this, I think that if GCC generates it, then it makes sense for
GDB to read it.

Tom