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

[Hui Zhu <teawater@gmail.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,
>
>