Re: [PATCH v2 2/2] gdb: retain thread-specific breakpoints in reverse execution targets

Bruno Larsen via Gdb-patches
2023-07-13T12:23:27Z

On 07/07/2023 18:24, Magne Hov via Gdb-patches wrote:
> Thread-specific breakpoints are currently ignored and removed (since
> 49fa26b0411d990d36f3f6c095d167f3d12afdf4) if the corresponding thread
> has exited. This makes sense for targets that only execute in the
> forward direction because those breakpoints can never be hit again, but
> for targets with reverse execution the same thread can be seen again.
> ---

Hi!

Thanks for working on this. Same as the other one, it looks good to go

Reviewed-By: Bruno Larsen <blarsen@redhat.com>

I hope a global maintainer or Markus look at it soon to approve it!

--
Cheers,
Bruno

> gdb/breakpoint.c | 18 +++++++++++++-----
> 1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
> index da6c8de9d14..9a25c5f663d 100644
> --- a/gdb/breakpoint.c
> +++ b/gdb/breakpoint.c
> @@ -3157,10 +3157,12 @@ insert_breakpoint_locations (void)
> continue;
>
> /* There is no point inserting thread-specific breakpoints if
> - the thread no longer exists. ALL_BP_LOCATIONS bp_location
> - has BL->OWNER always non-NULL. */
> + the thread no longer exists, unless the target supports
> + reverse execution. ALL_BP_LOCATIONS bp_location has
> + BL->OWNER always non-NULL. */
> if (bl->owner->thread != -1
> - && !valid_global_thread_id (bl->owner->thread))
> + && !valid_global_thread_id (bl->owner->thread)
> + && !target_can_execute_reverse ())
> continue;
>
> switch_to_program_space_and_thread (bl->pspace);
> @@ -3245,12 +3247,18 @@ remove_breakpoints (void)
> return val;
> }
>
> -/* When a thread exits, remove breakpoints that are related to
> - that thread. */
> +/* When a thread exits, remove breakpoints that are related to that
> + thread and cannot be hit again. */
>
> static void
> remove_threaded_breakpoints (struct thread_info *tp, int silent)
> {
> + /* Targets that support reverse execution may navigate to a point in
> + time where an exited thread reappears and where its breakpoints
> + are still relevant. */
> + if (target_can_execute_reverse ())
> + return;
> +
> for (breakpoint &b : all_breakpoints_safe ())
> {
> if (b.thread == tp->global_num && user_breakpoint_p (&b))