Re: [lizard] Fwd: CODITO - Reversible debugger

[Soam V. <soa...@co...>]

--- Kalpak Shah <kal...@gm...> wrote:
> Our BE project group is working at Codito. We were really inspired
> by LIZARD and have been thinking about reversible debugging. Sameer
> asked me to take your help for doubts regarding reversible debugger.

Ok

> Visual Basic has reversible debugging capability with the help of an
> interpreter which it uses at debugging stage. I found a few
> interpreters for C viz. Ch(www.softintegration.com) and EiC. EiC can
> be embedded or linked to other programs. We could use it along with
> GDB to provide this functionality.

Which functionality ?  Do you want to re-implement lizard ? why ?
(re-implementing lizard is not an invalid idea, i'm just asking you
why you're considering it.)

> There are good tools available for checkpointing to minimize the
> memory requirements, so checkpointing most probably should not be a
> problem. Would it be enough, if we can provide minimal functionality
> but prove that it is extensible?

Minimal functionality for what ?  Lizard already implements some
minimal functionality for a replay debugger, including checkpointing.

> Sameer also said that even if are able to change variable values in
> the executed code, it would be a good enough project. In this case
> we wouldnt need any recompilation.

Yeah, allowing users to change variable values during the debug
session would be a good feature; i'm not sure it's a big enough BE
project.  (But we'll certainly help you if you decide to do this.)

What is the case you are thinking of that requires recompilation ?

> What were the major roadblocks that you encountered when you thought
> about this idea? I thought that the recompilation of the changed
> code would be the biggest problem, but i guess it could be solved
> with the help of an interpreter.

Overall, I haven't really understood your email.  What exactly are you
looking for ?

Please have a look at http://lizard.sourceforge.net/explain.html .

If you're looking to extend lizard, we had, i think, thought of 3
new things that would be nice to do: (1) what-if capability
i.e. changing variable values (2) supporting multi-threaded programs
(3) supporting multi-processor programs.
These 3 things are in increasing order of difficulty.

There's also the list of bugs at
http://sourceforge.net/tracker/?group_id=112369&atid=662041

hope this helps.

regards,
soam