[RFA] Reverse Debugging, 1/5

[Joel Brobecker]

> 2008-09-30  Michael Snyder  <msnyder@vmware.com>
> 	Target interface for reverse debugging.
> 	* target.h (enum target_waitkind): 
> 	Add new wait event, TARGET_WAITKIND_NO_HISTORY.
> 	(enum exec_direction_kind): New enum.
> 	(struct target_ops): New methods to_set_execdir, to_get_execdir.
> 	* target.c (target_get_execdir): New generic method.
> 	(target_set_execdir): Ditto.

One of the questions I'm asking myself is why having the get_execdir
method? It seems that, once we have called "target_sets_execdir" and
it hasn't returned ERROR, core GDB should know what the execution
direction is, no? Is there a situation where a round-trip to the
target would be necessary?  Otherwise, we'll end up with the target
code all doing the same thing, which is caching the current value
of the same thing.

One thing that crossed my mind while thinking about it is whether
we want to make this property global to all inferiors or specific
to each inferior. Ahem, shall we say global?

-- 
Joel