Skip to content

gdb/infrun.c: fix handle_step_into_function lane divergence #181

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
lancesix wants to merge 2 commits into
base: amd-staging
Choose a base branch
from
+32 −6
Open

gdb/infrun.c: fix handle_step_into_function lane divergence #181

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
5f5fc3a
gdb/infrun.c: fix handle_step_into_function lane divergence
lancesix Jun 22, 2026
56206a0
gdb/infrun: improve stepping with lane divergence
lancesix Jun 23, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
38 changes: 32 additions & 6 deletions gdb/infrun.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -7906,11 +7906,37 @@ process_event_stop_test (struct execution_control_state *ecs)
&& (!ecs->event_thread->is_simd_lane_active
(ecs->event_thread->current_simd_lane ())))
{
infrun_debug_printf
("stepping divergent lane %s",
target_lane_to_str (ecs->event_thread,
ecs->event_thread->current_simd_lane ()).c_str ());

if (execution_direction == EXEC_FORWARD
&& (get_stack_frame_id (frame)
!= ecs->event_thread->control.step_stack_frame_id)
&& (frame_unwind_caller_id (frame)
== ecs->event_thread->control.step_stack_frame_id)
&& !ecs->event_thread->control.in_step_start_function (frame))
{
/* We just stepped inside a new function, but the current lane
is inactive. None of the architectures we support can jump to a
new frame while changing the active lanes, so the current lane
was inactive on the call site.

Because the lane was inactive on the call site, we expect that
lane to remain inactive for the entire frame. Therefore, even if
we issued a next, the current lane should ont become active until
we return from the current frame. We can return directly to
the caller. */
infrun_debug_printf
("stepping into subroutine with divergent lane %s",
target_lane_to_str (ecs->event_thread,
ecs->event_thread->current_simd_lane ()
).c_str ());
insert_step_resume_breakpoint_at_caller (frame);
}
else
{
infrun_debug_printf
("stepping divergent lane %s",
target_lane_to_str (ecs->event_thread,
ecs->event_thread->current_simd_lane ()).c_str ());
}
keep_going (ecs);
return;
}
Expand Down Expand Up @@ -8951,7 +8977,7 @@ handle_step_into_function (struct gdbarch *gdbarch,
end_stepping_range (ecs);
return;
}
else
else if (ecs->event_thread->stop_pc () < ecs->stop_func_start)
{
/* Put the step-breakpoint there and go until there. */
symtab_and_line sr_sal;
Expand Down
Loading