Re: [discuss] Support for reverse-execution

[Michael Snyder <msnyder at redhat dot com>]

In regards to the question "where does a reverse-step put you?"
(ie. at the beginning of a line, or somewhere in the line):

> Sorry, I'm confused.  Isn't it right that if I'm stepping
> backwards through code such as this:
>
>    i += 1;
>    foo (i);
>  =>i = 0;
>
> where "=>" shows the current source line, then typing `rnext'
> once will get me to this:
>
>    i += 1;
>  =>foo (i);
>    i = 0;
>
> which means I'm now before the CALL insn that calls `foo'?

I agree with this interpretation.  If I am a user (and I am),
and I were to say:
    (gdb) step
    (gdb) reverse-step (or whatever)
I would expect to be back where I started, ie. at the
*beginning* of the original line.

Dan J. has said that we might need to reverse-stepi until
we've gone back one too many, and then do a forward step.
I agree.  In fact, I think it will be necessary to do
the following:

    (gdb) reverse-step
    # reverse-stepi once (or until we leave the *current* line)
    # now establish the step-range start and end (prev line)
    # reverse-stepi until we leave the prev line
    # stepi once to get back to the desired line.