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Re: Stop breakpoint commands from poping the target

A Saturday 15 March 2008 15:58:59, Vladimir Prus escreveu:
> Pedro Alves wrote:
> > This patch goes on top of Vladimir's pending async fixes patch.
> >
> > commands.exp triggers the problem this patch addresses, in
> > async mode.
> >
> > In that test, we have a watch on a local variable, and then we
> > add a command to that watch to print the local variable's
> > value.  When the variable goes out of scope, gdb prints that,
> > and also runs the associated commands with the watch.  Since
> > the variable is out of scope, and error is thrown.  In sync
> > targets, the exception just ends the breakpoints command
> > processing, and goes on to proceed with the command loop.  But in
> > async mode, the exception ends up in
> > inf-loop.c:inferior_event_handler/INF_REG_EVENT, which considers
> > exceptions fatal, and pops the target.  The fix is to catch the exception
> > earlier.
> Why do we pop the target in the first place? It does not seem like
> a good idea to do that if any exception is thrown.
> I actually agree that if breakpoint commands fail, it's not
> then end of world, and we can go on with continuations.  But at the same
> time, popping target on any unhandled exception sounds a little bit
> drastic.

I don't know why we're doing that.  Maybe it should have been an
internal error, or maybe we'll find a case where an exception must
not be caught there.

It's not even a good job in doing the popping it either.  The target
is left in some undefined state.  

Pedro Alves

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