Re: Teach gdbserver to step over internal breakpoints

[Pedro Alves <pedro@codesourcery.com>]

On Tuesday 16 March 2010 18:39:52, Pedro Alves wrote:
> This tests cleanly on x86_64-linux, native gdbserver, with
> a small hack to force it to use the thread event breakpoint.
> I'll confirm this doesn't break software-single-step archs
> before commiting, although I don't expect to, since I had
> tested an earlier version of this patch on ARM.

I've now tested this on arm-none-linux-gnueabi,
and there were no regressions.  I've also re-tested this
on x86_64-linux.  It's now checked in.

> 2010-03-16  Pedro Alves  <pedro@codesourcery.com>
> 
>         gdb/gdbserver/
>         * linux-low.c (can_hardware_single_step): New.
>         (supports_breakpoints): New.
>         (handle_extended_wait): If stopping threads, read the stop pc of
>         the new cloned LWP.
>         (get_pc): New.
>         (get_stop_pc): Add `lwp' parameter.  Handle it.  Bail out if the
>         low target doesn't support retrieving the PC.
>         (add_lwp): Set last_resume_kind to resume_continue.
>         (linux_attach_lwp_1): Adjust comments.  Always set stop_expected.
>         (linux_attach): Don't clear stop_expected.  Set the lwp's
>         last_resume_kind to resume_stop.
>         (linux_detach_one_lwp): Don't check for removed breakpoints.
>         (check_removed_breakpoint): Delete.
>         (status_pending_p): Rename to ...
>         (status_pending_p_callback): ... this.  Don't check for removed
>         breakpoints.  Don't consider threads that are stopped from GDB's
>         perspective.
>         (linux_wait_for_lwp): Always read the stop_pc here.
>         (cancel_breakpoint): New.
>         (step_over_bkpt): New global.
>         (linux_wait_for_event_1): Implement stepping over breakpoints.
>         (gdb_wants_lwp_stopped): New.
>         (gdb_wants_all_stopped): New.
>         (linux_wait_1): Tag threads as gdb-wants-stopped.  Cancel finished
>         single-step traps here.  Store the thread's last reported target
>         wait status.
>         (send_sigstop): Don't clear stop_expected.  Always set it,
>         instead.
>         (mark_lwp_dead): Remove reference to pending_is_breakpoint.
>         (cancel_finished_single_step): New.
>         (cancel_finished_single_steps): New.
>         (wait_for_sigstop): Don't cancel finished single-step traps here.
>         (linux_resume_one_lwp): Don't check for removed breakpoints.
>         Don't set `step' on non-hardware step archs.
>         (linux_set_resume_request): Ignore resume_stop requests if already
>         stopping or stopped.  Set the lwp's last_resume_kind.
>         (resume_status_pending_p): Don't check for removed breakpoints.
>         (need_step_over_p): New.
>         (start_step_over): New.
>         (finish_step_over): New.
>         (linux_resume_one_thread): Always queue a sigstop for resume_stop
>         requests.  Clear the thread's last reported target waitstatus.
>         Don't use the `suspended' flag.  Don't consider pending breakpoints.
>         (linux_resume): Start a step-over if necessary.
>         (proceed_one_lwp): New.
>         (proceed_all_lwps): New.
>         (unstop_all_lwps): New.
>         * linux-low.h (struct lwp_info): Rewrite comment for the
>         `suspended' flag.  Add the `stop_pc' field.  Delete the
>         `pending_stop_pc' field.  Tweak the `stepping' flag's comment.
>         Add `'last_resume_kind' and `need_step_over' fields.
>         * inferiors.c (struct thread_info): Delete, moved elsewhere.
>         * mem-break.c (struct breakpoint): Delete `reinserting' flag.
>         Delete `breakpoint_to_reinsert' field.  New flag `inserted'.
>         (set_raw_breakpoint_at): New.
>         (set_breakpoint_at): Rewrite to use it.
>         (reinsert_breakpoint_handler): Delete.
>         (set_reinsert_breakpoint): New.
>         (reinsert_breakpoint_by_bp): Delete.
>         (delete_reinsert_breakpoints): New.
>         (uninsert_breakpoint): Rewrite.
>         (uninsert_breakpoints_at): New.
>         (reinsert_breakpoint): Rewrite.
>         (reinsert_breakpoints_at): New.
>         (check_breakpoints): Rewrite.
>         (breakpoint_here): New.
>         (breakpoint_inserted_here): New.
>         (check_mem_read): Adjust.
>         * mem-break.h (breakpoints_supported, breakpoint_here)
>         (breakpoint_inserted_here, set_reinsert_breakpoint): Declare.
>         (reinsert_breakpoint_by_bp): Delete declaration.
>         (delete_reinsert_breakpoints): Declare.
>         (reinsert_breakpoint): Delete declaration.
>         (reinsert_breakpoints_at): Declare.
>         (uninsert_breakpoint): Delete declaration.
>         (uninsert_breakpoints_at): Declare.
>         (check_breakpoints): Adjust prototype.
>         * server.h: Adjust include order.
>         (struct thread_info): Declare here.  Add a `last_status' field.


-- 
Pedro Alves