Re: [PATCH] Fix signals.exp test case on S/390

Ulrich Weigand
2004-03-11T17:11:03Z

> > It will run into the first if, and simply use step_frame_id,
> > which is wrong in this case. That's why my patch add another
> > condition to the first if, to make it not taken and actually
> > use the (correct) get_prev_frame case.
>
> Where is step_frame_id pointing?

To the function that was interrupted by the signal (i.e. the
function where I entered 'next').

> Anyway, I think this code:
> > if (frame_id_p (step_frame_id)
> > && !IN_SOLIB_DYNSYM_RESOLVE_CODE (sr_sal.pc))
> > /* NOTE: cagney/2004-02-27: Use the global state's idea of the
> > stepping frame ID. I suspect this is done as it is lighter
> > weight than a call to get_prev_frame. */
> > sr_id = step_frame_id;
> should simply be deleted. I wondered about it and you've just confirmed
> my suspicions. With that code gone is half the problem solved?

Yes, deleting this works just fine for me, in fact ...

> That leaves the other problem, which is much harder :-(

... it even solves the other problem as well!

The reason for this is that the whole problematic if
that uses frame_id_inner becomes irrelevant:

if (pc_in_sigtramp (stop_pc)
&& frame_id_inner (step_frame_id,
frame_id_build (read_sp (), 0)))
/* We stepped out of a signal handler, and into its
calling trampoline. This is misdetected as a
subroutine call, but stepping over the signal
trampoline isn't such a bad idea. In order to do that,
we have to ignore the value in step_frame_id, since
that doesn't represent the frame that'll reach when we
return from the signal trampoline. Otherwise we'll
probably continue to the end of the program. */
step_frame_id = null_frame_id;

step_over_function (ecs);

With those lines in step_over_function deleted, step_over_function
does not care about step_frame_id at all any more, and thus there
is no need to fiddle with step_frame_id here ...

> > Finally, the patch below reintroduces a pc_in_sigtramp
> > gdbarch callback to s390-tdep.c; I had thought this would
> > be no longer necessary when using the new frame code, but
> > apparently there's still other users ...
>
> Yes, it shouldn't be needed. get_frame_type == SIGTRAMP_FRAME is
> sufficient. work-in-progress.

Actually, when deleting the lines in step_over_function, it turns
out that I don't need pc_in_sigtramp any more ...

Summing up: after completely reverting my patch, and simply
deleting those lines, I get a gdb that passes signals.exp
(and has no test suite regressions), and also handles stepping
out of a signal handler correctly.