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

[Hui Zhu <teawater at gmail dot com>]

I tried this patch with ubuntu i386.  Everything is OK.

Thanks,
Hui

On Sat, Jul 4, 2009 at 08:32, Michael Snyder<msnyder@vmware.com> 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,
>
>