Re: [rfa/c++] cp_lookup_rtti_type, take 2

Daniel Jacobowitz
2003-12-05T17:40:20Z

On Fri, Dec 05, 2003 at 09:38:52AM -0800, David Carlton wrote:
> On Fri, 5 Dec 2003 12:16:58 -0500, Daniel Jacobowitz <drow@mvista.com> said:
>
> > How do you suggest we do it? Some new addition to the debug info? I
> > don't believe we have anything at the moment that fills this need.
>
> Hmm. I thought I'd seen something appropriate in the debug info, but
> now I realize that I was looking for the slot for the vtable in the
> class, which is a quite different matter.
>
> Well, here's what I see when looking for a vtable symbol in a sample
> file:
>
> .uleb128 0x1d # (DIE (0x20d) DW_TAG_variable)
> .long .LC9 # DW_AT_name: "_ZTI1C"
> .long 0x21e # DW_AT_type
> .byte 0x1 # DW_AT_external
> .byte 0x1 # DW_AT_artificial
> .byte 0x5 # DW_AT_location
> .byte 0x3 # DW_OP_addr
> .long _ZTI1C
>
> So DW_TAG_variable + DW_AT_artificial is a start - looking for that
> (plus perhaps guiltily peeking at the demanged name just to make sure
> it starts with 'typeinfo') lets us find the vtable symbols. But that
> doesn't help - the DW_AT_type doesn't actually lead us to the type
> that it's the vtable for, and certainly none of the other attributes
> are going to help.
>
> Sigh.

If you think this _should_ be in the debug info, you may want to draft
a proposed extension.

--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer