Re: [discuss] Support for reverse-execution

[Daniel Jacobowitz <drow@false.org>]

On Fri, May 20, 2005 at 06:01:44PM -0400, Paul Schlie wrote:
> > From: Dan Shearer <dan@shearer.org>
> > In the longer term yes, GDB should be able to debug with a sense of
> > direction and time. But I think it will take quite a bit of experimentation
> > before we have a clear model of how to do this, and the only way I can think
> > of for both having a reversible GDB and not touching GDB too much is by
> > considering remote targets first.
> 
> - Then you'll end up with nothing more than an interface to a propriety
>   simulator, which doesn't seem like a good goal or approach for GDB.

This argument is so bogus that I need to call you on it.  You end up
with a reasonable interface to _any_ simulator, whether proprietary or
not.  The details of an efficient implementation will be obviously
dependent on the simulator's state and implementation.

I am inclined to agree with the posted proposals that the
implementation of reverse-stepi should be opaque to GDB, at least for
now.  The performance of shuffling state diffs over the remote protocol
- or even just references to them - would be horrid.  It also means
that GDB will be limited to a particular class of implementations of
reversible simulation instead of the concept of reversible simulation.

You're describing something which may be interesting, someday.  Do feel
welcome to implement it; we'll be glad to help.  I don't think that
it's inherently more appropriate than the proposed interface, though.

-- 
Daniel Jacobowitz
CodeSourcery, LLC