[Dwarf-Discuss] Issue 100805.1 dynamic properties of types: reference interpretation

[Mark Wielaard]

On Fri, 2014-03-28 at 15:18 -0700, Cary Coutant wrote:
> > The proposed DWARF5 suggestion "dynamic properties of types: reference
> > interpretation" http://dwarfstd.org/ShowIssue.php?issue=100805.1 says:
> > [...]
> We did discuss this at the September meeting, but the issue page
> didn't get updated correctly. The revised text was supposed to be
> this:
> 
> For a reference, the value is a reference to another DIE.  This DIE may
>     -- describe a variable which contains the attribute value
>     -- describes a constant which is the attribute value
>     -- contain a DWARF expression which computes the attribute value
> or is a dwarf procedure which computes the attribute
> value
> 
> (Even as is, I think the wording is just a little off. We may need to
> tweak it a bit.)

Aha. That makes more sense to me. Thanks.

If it really should be an clarification then I think it would be good to
be more specific. The phrases "contains the attribute value" and
"computes the attribute value" are still not very concrete. I assume
what is meant is that the DIE may have either:

- a DW_AT_location attribute whose exprloc or loclistptr value describes
  the location of the property value.
- or a DW_AT_const_value attribute whose block, constant or string
  value is the actual constant property value.

That seems to capture the above in lesser points. But maybe it is too
specific? I do think it would be good to list the attributes (and form
encodings), or at least be more specific about which attributes (and
form encodings), the consumer is expected to evaluate in the referenced
DIE.

Cheers,

Mark