Re: [RFA] improved handling of shared lib calls (reverse 2/2)

[Hui Zhu <teawater at gmail dot com>]

I try this patch with cvs-head and program:
void foo() {
    return;
}

int main() {

	foo(); // 1
	foo(); // 2
	foo(); // 3

	return 0;
}
in ubuntu i386.
And test with reverse testsuite.
Everything is OK.

Thanks,
Hui


On Wed, Jul 15, 2009 at 09:08, Michael Snyder<msnyder@vmware.com> wrote:
> And now this one?
>
> Michael Snyder wrote:
>>
>> Now how about this one?
>>
>> Michael Snyder wrote:
>>>
>>> This change depends on the previous one (epilogue unwinder for i386,
>>> http://sourceware.org/ml/gdb-patches/2009-07/msg00099.html).
>>>
>>> With the frame unwinder working properly, we can remove the
>>> special case code in the test for "check for subroutine call"
>>> in handle_inferior_event.
>>>
>>> Of course that reveals some hidden problems with shared library
>>> calls, so this patch also addresses those.
>>>
>>> Michael
>>>
>>>
>>>
>>> ------------------------------------------------------------------------
>>>
>>> 2009-07-03 ?Michael Snyder ?<msnyder@vmware.com>
>>>
>>> ? ? ? ?* infrun.c (handle_inferior_event): Remove an execution_direction
>>> ? ? ? ?check in the "check for subroutine calls" test, and add some
>>> ?additional handling for reverse-stepping through shared libraries.
>>>
>>> Index: infrun.c
>>> ===================================================================
>>> RCS file: /cvs/src/src/gdb/infrun.c,v
>>> retrieving revision 1.400
>>> diff -u -p -r1.400 infrun.c
>>> --- infrun.c ? ?2 Jul 2009 17:21:06 -0000 ? ? ? 1.400
>>> +++ infrun.c ? ?4 Jul 2009 00:27:53 -0000
>>> @@ -3776,9 +3776,8 @@ infrun: not switching back to stepped th
>>> ? ? ?previous frame must have valid frame IDs. ?*/
>>> ? if (!frame_id_eq (get_stack_frame_id (frame),
>>> ? ? ? ? ? ? ? ? ? ?ecs->event_thread->step_stack_frame_id)
>>> - ? ? ?&& (frame_id_eq (frame_unwind_caller_id (frame),
>>> - ? ? ? ? ? ? ? ? ? ? ?ecs->event_thread->step_stack_frame_id)
>>> - ? ? ? ? || execution_direction == EXEC_REVERSE))
>>> + ? ? ?&& frame_id_eq (frame_unwind_caller_id (frame),
>>> + ? ? ? ? ? ? ? ? ? ? ecs->event_thread->step_stack_frame_id))
>>> ? ? {
>>> ? ? ? CORE_ADDR real_stop_pc;
>>> ?@@ -3806,6 +3805,7 @@ infrun: not switching back to stepped th
>>> ? ? ? /* Reverse stepping through solib trampolines. ?*/
>>> ? ? ? ? if (execution_direction == EXEC_REVERSE
>>> + ? ? ? ? && ecs->event_thread->step_over_calls != STEP_OVER_NONE
>>> ? ? ? ? ?&& (gdbarch_skip_trampoline_code (gdbarch, frame, stop_pc)
>>> ? ? ? ? ? ? ?|| (ecs->stop_func_start == 0
>>> ? ? ? ? ? ? ? ? ?&& in_solib_dynsym_resolve_code (stop_pc))))
>>> @@ -3923,6 +3923,38 @@ infrun: not switching back to stepped th
>>> ? ? ? return;
>>> ? ? }
>>> ?+ ?/* Reverse stepping through solib trampolines. ?*/
>>> +
>>> + ?if (execution_direction == EXEC_REVERSE
>>> + ? ? ?&& ecs->event_thread->step_over_calls != STEP_OVER_NONE)
>>> + ? ?{
>>> + ? ? ?if (gdbarch_skip_trampoline_code (gdbarch, frame, stop_pc)
>>> + ? ? ? ? || (ecs->stop_func_start == 0
>>> + ? ? ? ? ? ? && in_solib_dynsym_resolve_code (stop_pc)))
>>> + ? ? ? {
>>> + ? ? ? ? /* Any solib trampoline code can be handled in reverse
>>> + ? ? ? ? ? ?by simply continuing to single-step. ?We have already
>>> + ? ? ? ? ? ?executed the solib function (backwards), and a few +
>>> ? ?steps will take us back through the trampoline to the
>>> + ? ? ? ? ? ?caller. ?*/
>>> + ? ? ? ? keep_going (ecs);
>>> + ? ? ? ? return;
>>> + ? ? ? }
>>> + ? ? ?else if (in_solib_dynsym_resolve_code (stop_pc))
>>> + ? ? ? {
>>> + ? ? ? ? /* Stepped backward into the solib dynsym resolver.
>>> + ? ? ? ? ? ?Set a breakpoint at its start and continue, then
>>> + ? ? ? ? ? ?one more step will take us out. ?*/
>>> + ? ? ? ? struct symtab_and_line sr_sal;
>>> + ? ? ? ? init_sal (&sr_sal);
>>> + ? ? ? ? sr_sal.pc = ecs->stop_func_start;
>>> + ? ? ? ? insert_step_resume_breakpoint_at_sal (gdbarch, +
>>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? sr_sal, null_frame_id);
>>> + ? ? ? ? keep_going (ecs);
>>> + ? ? ? ? return;
>>> + ? ? ? }
>>> + ? ?}
>>> +
>>> ? /* If we're in the return path from a shared library trampoline,
>>> ? ? ?we want to proceed through the trampoline when stepping. ?*/
>>> ? if (gdbarch_in_solib_return_trampoline (gdbarch,
>>
>>
>
>