Re: 8-byte register values on a 32-bit machine

Daniel Jacobowitz
2003-03-12T17:01:06Z

On Wed, Mar 12, 2003 at 11:57:49AM -0500, Andrew Cagney wrote:
>
> >The new code fixes some reported wrong-value-reported bugs in other
> >debugging
> >situations; one of them was reported just recently. So I don't think
> >'equalled the functionality of the old mechanism' is really quite fair.
> >
> >I was also not aware that we had sketchy multi-register support until
> >it was pointed out to me, because the support isn't in any of the
> >places I was working in directly; it's off in the generic value code,
> >isn't it? So I didn't know this was going to happen. We have a plan
> >to fix it, too. Mark posted it, and then ran out of time (?). You
> >didn't like his plan because:
>
> > I think it is very dangerous. It's assuming a specific algorithm
> > in the compiler. That locks both GDB and GCC into something of a
> > death spiral. I think its far better to try and get a proper
> > location mechanism working.
>
> There are other ways forward on this - moving the algorithm to libiberty
> (like the demangler).

This is a target-specific allocation order, for communication between
GCC and GDB, not a matter of published interfaces - I don't think it
belongs in libiberty. It's subject to change, but I have a reasonable
expectation that it won't change until after debugging info to express
it is available.

In any case I'm going back to working on locations as objects, which is
the next step in fixing this properly.

--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer