Re: [PATCH] Accept DWARF 3-format debug info

[Daniel Jacobowitz <drow at false dot org>]

On Fri, Jun 09, 2006 at 07:41:54PM +0300, Eli Zaretskii wrote:
> > On Fri, Jun 09, 2006 at 10:28:07AM +0300, Eli Zaretskii wrote:
> > > In this case, what will happen when GDB sees a DWARF-3 feature it
> > > doesn't yet support?  I think we should make sure it displays a
> > > warning message, instead of throwing an internal error (or some
> > > similar fatal reaction).
> > 
> > Same thing that happens when we see a DWARF-2 feature we don't support
> > ;-)
> 
> Which is -- what?  (I really don't know.)

It depends.  We try to ignore it.  However, often debugging information
relies on some new construct in place of an older, less expressive one.

Syntactically, GDB will cope with most unrecognized constructs just
fine.  Semantically, however, if it doesn't recognize something it may
not cope well with debugging.  This is already very true for DWARF-2;
some of the other patches Julian will be posting are along those lines.

> > GCC is actually a DWARF-3 producer in almost all ways.  It just didn't
> > bump the version number, to avoid upsetting consumers, since most of
> > the changes are forwards-compatible.
> 
> Well, the same reasons GCC had to avoid upsetting consumers might be
> relevant for us as well, don't you think?

No, because we're a consumer of this information, not a producer.  This
is a "conservative in what you generate, liberal in what you accept"
sort of situation.  Strictly speaking, we're handling a lot of tags in
DWARF-2 that aren't really part of DWARF-2 - but that's harmless.

-- 
Daniel Jacobowitz
CodeSourcery