RE: [PATCH 4/8] gdb, infrun: refactor part of `proceed` into separate function

Aktemur, Tankut Baris via Gdb-patches
2023-06-28T08:49:29Z

On Thursday, June 22, 2023 3:17 PM, Andrew Burgess wrote:
> From: Mihails Strasuns <mihails.strasuns@intel.com>
>
> Split the thread resuming code from proceed into new function
> proceed_resume_thread_checked.
>
> Co-Authored-By: Christina Schimpe <christina.schimpe@intel.com>
> ---
> gdb/infrun.c | 148 +++++++++++++++++++++++++++------------------------
> 1 file changed, 79 insertions(+), 69 deletions(-)
>
> diff --git a/gdb/infrun.c b/gdb/infrun.c
> index 5b0257076f0..b10b7c59652 100644
> --- a/gdb/infrun.c
> +++ b/gdb/infrun.c
> @@ -3268,6 +3268,82 @@ check_multi_target_resumption (process_stratum_target *resume_target)
> }
> }
>
> +/* Helper function for `proceed`. Check if thread TP is suitable for
> + resuming, and, if it is, switch to the thread and call
> + `keep_going_pass_signal`. If TP is not suitable for resuming then this
> + function will just return without switching threads. */
> +
> +static void
> +proceed_resume_thread_checked (thread_info *tp)
> +{
> + if (!tp->inf->has_execution ())
> + {
> + infrun_debug_printf ("[%s] target has no execution",
> + tp->ptid.to_string ().c_str ());
> + return;
> + }
> +
> + if (tp->resumed ())
> + {
> + infrun_debug_printf ("[%s] resumed",
> + tp->ptid.to_string ().c_str ());
> + gdb_assert (tp->executing () || tp->has_pending_waitstatus ());
> + return;
> + }
> +
> + if (thread_is_in_step_over_chain (tp))
> + {
> + infrun_debug_printf ("[%s] needs step-over",
> + tp->ptid.to_string ().c_str ());
> + return;
> + }
> +
> + /* When handling a vfork GDB removes all breakpoints from the program
> + space in which the vfork is being handled, as such we must take care
> + not to resume any thread other than the vfork parent -- resuming the
> + vfork parent allows GDB to receive and handle the 'vfork done'
> + event. */
> + if (tp->inf->thread_waiting_for_vfork_done != nullptr)
> + {
> + if (target_is_non_stop_p ())
> + {
> + /* For non-stop targets, regardless of whether GDB is using
> + all-stop or non-stop mode, threads are controlled
> + individually.
> +
> + When a thread is handling a vfork, breakpoints are removed
> + from the inferior (well, program space in fact), so it is
> + critical that we don't try to resume any thread other than the
> + vfork parent. */
> + if (tp != tp->inf->thread_waiting_for_vfork_done)
> + {
> + infrun_debug_printf ("[%s] thread %s of this inferior is "
> + "waiting for vfork-done",
> + tp->ptid.to_string ().c_str (),
> + tp->inf->thread_waiting_for_vfork_done
> + ->ptid.to_string ().c_str ());
> + return;
> + }
> + }
> + else
> + {
> + /* For all-stop targets, when we attempt to resume the inferior,
> + we will in fact only resume the vfork parent thread, this is
> + handled in internal_resume_ptid, as such, there is nothing
> + more that needs doing here. */

I wonder if here we should do

gdb_assert (tp == tp->inf->thread_waiting_for_vfork_done);

-Baris

> + }
> + }
> +
> + infrun_debug_printf ("resuming %s",
> + tp->ptid.to_string ().c_str ());
> +
> + execution_control_state ecs (tp);
> + switch_to_thread (tp);
> + keep_going_pass_signal (&ecs);
> + if (!ecs.wait_some_more)
> + error (_("Command aborted."));
> +}
> +
> /* Basic routine for continuing the program in various fashions.
>
> ADDR is the address to resume at, or -1 for resume where stopped.
> @@ -3456,77 +3532,11 @@ proceed (CORE_ADDR addr, enum gdb_signal siggnal)
> resume_ptid))
> {
> switch_to_thread_no_regs (tp);
> -
> - if (!tp->inf->has_execution ())
> - {
> - infrun_debug_printf ("[%s] target has no execution",
> - tp->ptid.to_string ().c_str ());
> - continue;
> - }
> -
> - if (tp->resumed ())
> - {
> - infrun_debug_printf ("[%s] resumed",
> - tp->ptid.to_string ().c_str ());
> - gdb_assert (tp->executing () || tp->has_pending_waitstatus ());
> - continue;
> - }
> -
> - if (thread_is_in_step_over_chain (tp))
> - {
> - infrun_debug_printf ("[%s] needs step-over",
> - tp->ptid.to_string ().c_str ());
> - continue;
> - }
> -
> - /* If a thread of that inferior is waiting for a vfork-done
> - (for a detached vfork child to exec or exit), breakpoints are
> - removed. We must not resume any thread of that inferior, other
> - than the one waiting for the vfork-done. */
> - if (tp->inf->thread_waiting_for_vfork_done != nullptr
> - && tp != tp->inf->thread_waiting_for_vfork_done)
> - {
> - infrun_debug_printf ("[%s] another thread of this inferior is "
> - "waiting for vfork-done",
> - tp->ptid.to_string ().c_str ());
> - continue;
> - }
> -
> - infrun_debug_printf ("resuming %s",
> - tp->ptid.to_string ().c_str ());
> -
> - execution_control_state ecs (tp);
> - switch_to_thread (tp);
> - keep_going_pass_signal (&ecs);
> - if (!ecs.wait_some_more)
> - error (_("Command aborted."));
> - }
> - }
> - else if (!cur_thr->resumed ()
> - && !thread_is_in_step_over_chain (cur_thr))
> - {
> - /* In non-stop mode, if a there exists a thread waiting for a vfork
> - then only allow that thread to resume (breakpoints are removed
> - from an inferior when handling a vfork).
> -
> - We check target_is_non_stop_p here rather than just checking the
> - non-stop flag, though these are equivalent (all-stop on a
> - non-stop target was handled in a previous block, so at this
> - point, if target_is_non_stop_p then GDB must be running on
> - non-stop mode). By using target_is_non_stop_p it will be easier
> - to merge this block with the previous in a later commit. */
> - if (!(target_is_non_stop_p ()
> - && cur_thr->inf->thread_waiting_for_vfork_done != nullptr
> - && cur_thr->inf->thread_waiting_for_vfork_done != cur_thr))
> - {
> - /* The thread wasn't started, and isn't queued, run it now. */
> - execution_control_state ecs (cur_thr);
> - switch_to_thread (cur_thr);
> - keep_going_pass_signal (&ecs);
> - if (!ecs.wait_some_more)
> - error (_("Command aborted."));
> + proceed_resume_thread_checked (tp);
> }
> }
> + else
> + proceed_resume_thread_checked (cur_thr);
>
> disable_commit_resumed.reset_and_commit ();
> }
> --
> 2.25.4

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