[Bug gdb/20487] Thread sync broken between mi and cli with new-ui command

["cvs-commit at gcc dot gnu.org" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=20487

--- Comment #14 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The gdb-7.12-branch branch has been updated by Simon Marchi
<simark@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=1555a1e7846048adeee7b9734ab3ec200d776858

commit 1555a1e7846048adeee7b9734ab3ec200d776858
Author: Antoine Tremblay <antoine.tremblay@ericsson.com>
Date:   Mon Oct 3 16:52:44 2016 -0400

    Emit inferior, thread and frame selection events to all UIs

    With this patch, when an inferior, thread or frame is explicitly
    selected by the user, notifications will appear on all CLI and MI UIs.
    When a GDB console is integrated in a front-end, this allows the
    front-end to follow a selection made by the user ont he CLI, and it
    informs the user about selection changes made behind the scenes by the
    front-end.

    This patch addresses PR gdb/20487.

    In order to communicate frame changes to the front-end, this patch adds
    a new field to the =thread-selected event for the selected frame.  The
    idea is that since inferior/thread/frame can be seen as a composition,
    it makes sense to send them together in the same event.  The vision
    would be to eventually send the inferior information as well, if we find
    that it's needed, although the "=thread-selected" event would be
    ill-named for that job.

    Front-ends need to handle this new field if they want to follow the
    frame selection changes that originate from the console.  The format of
    the frame attribute is the same as what is found in the *stopped events.

    Here's a detailed example for each command and the events they generate:

    thread
    ------

    1. CLI command:

         thread 1.3

       MI event:

         =thread-selected,id="3",frame={...}

    2. MI command:

         -thread-select 3

       CLI event:

         [Switching to thread 1.3 ...]

    3. MI command (CLI-in-MI):

         thread 1.3

       MI event/reply:

         &"thread 1.3\n"
         ~"#0  child_sub_function () ...
         =thread-selected,id="3",frame={level="0",...}
         ^done

    frame
    -----

    1. CLI command:

         frame 1

       MI event:

         =thread-selected,id="3",frame={level="1",...}

    2. MI command:

         -stack-select-frame 1

       CLI event:

         #1  0x00000000004007f0 in child_function...

    3. MI command (CLI-in-MI):

         frame 1

       MI event/reply:

         &"frame 1\n"
         ~"#1  0x00000000004007f9 in ..."
         =thread-selected,id="3",frame={level="1"...}
         ^done

    inferior
    --------

    Inferior selection events only go from the console to MI, since there's
    no way to select the inferior in pure MI.

    1. CLI command:

         inferior 2

       MI event:

         =thread-selected,id="3"

    Note that if the user selects an inferior that is not started or exited,
    the MI doesn't receive a notification.  Since there is no threads to
    select, the =thread-selected event does not apply...

    2. MI command (CLI-in-MI):

         inferior 2

       MI event/reply:

         &"inferior 2\n"
         ~"[Switching to inferior 2 ...]"
         =thread-selected,id="4",frame={level="0"...}
         ^done

    Internal implementation detail: this patch makes it possible to suppress
    notifications caused by a CLI command, like what is done in mi-interp.c.
    This means that it's now possible to use the
    add_com_suppress_notification function to register a command with some
    event suppressed.  It is used to implement the select-frame command in
    this patch.

    The function command_notifies_uscc_observer was added to extract
    the rather complicated logical expression from the if statement.  It is
    also now clearer what that logic does: if the command used by the user
    already notifies the user_selected_context_changed observer, there is
    not need to notify it again.  It therefore protects again emitting the
    event twice.

    No regressions, tested on ubuntu 14.04 x86 with target boards unix and
    native-extended-gdbserver.

    gdb/ChangeLog:

    YYYY-MM-DD  Antoine Tremblay  <antoine.tremblay@ericsson.com>
    YYYY-MM-DD  Simon Marchi  <simon.marchi@ericsson.com>

        PR gdb/20487
        * NEWS: Mention new frame field of =thread-selected event.
        * cli/cli-decode.c (add_cmd): Initialize c->suppress_notification.
        (add_com_suppress_notification): New function definition.
        (cmd_func): Set and restore the suppress_notification flag.
        * cli/cli-deicode.h (struct cmd_list_element)
        <suppress_notification>: New field.
        * cli/cli-interp.c (cli_suppress_notification): New global variable.
        (cli_on_user_selected_context_changed): New function.
        (_initialize_cli_interp): Attach to user_selected_context_changed
        observer.
        * command.h (struct cli_suppress_notification): New structure.
        (cli_suppress_notification): New global variable declaration.
        (add_com_suppress_notification): New function declaration.
        * defs.h (enum user_selected_what_flag): New enum.
        (user_selected_what): New enum flag type.
        * frame.h (print_stack_frame_to_uiout): New function declaration.
        * gdbthread.h (print_selected_thread_frame): New function declaration.
        * inferior.c (print_selected_inferior): New function definition.
        (inferior_command): Remove printing of inferior/thread/frame switch
        notifications, notify user_selected_context_changed observer.
        * inferior.h (print_selected_inferior): New function declaration.
        * mi/mi-cmds.c (struct mi_cmd): Add user_selected_context
        suppression to stack-select-frame and thread-select commands.
        * mi/mi-interp.c (struct mi_suppress_notification)
        <user_selected_context>: Initialize.
        (mi_user_selected_context_changed): New function definition.
        (_initialize_mi_interp): Attach to user_selected_context_changed.
        * mi/mi-main.c (mi_cmd_thread_select): Print thread selection reply.
        (mi_execute_command): Handle notification suppression.  Notify
        user_selected_context_changed observer on thread change instead of
printing
        event directly.  Don't send it if command already sends the
notification.
        (command_notifies_uscc_observer): New function.
        (mi_cmd_execute): Don't handle notification suppression.
        * mi/mi-main.h (struct mi_suppress_notification)
        <user_selected_context>: New field.
        * stack.c (print_stack_frame_to_uiout): New function definition.
        (select_frame_command): Notify user_selected_context_changed
        observer.
        (frame_command): Call print_selected_thread_frame if there's no frame
        change or notify user_selected_context_changed observer if there is.
        (up_command): Notify user_selected_context_changed observer.
        (down_command): Likewise.
        (_initialize_stack): Suppress user_selected_context notification for
        command select-frame.
        * thread.c (thread_command): Notify
        user_selected_context_changed if the thread has changed, print
        thread info directly if it hasn't.
        (do_captured_thread_select): Do not print thread switch event.
        (print_selected_thread_frame): New function definition.
        * tui/tui-interp.c (tui_on_user_selected_context_changed):
        New function definition.
        (_initialize_tui_interp): Attach to user_selected_context_changed
        observer.

    gdb/doc/ChangeLog:

        PR gdb/20487
        * gdb.texinfo (Context management): Update mention of frame
        change notifications.
        (gdb/mi Async Records): Document frame field in
        =thread-select event.
        * observer.texi (GDB Observers): New user_selected_context_changed
        observer.

    gdb/testsuite/ChangeLog:

        PR gdb/20487
        * gdb.mi/mi-pthreads.exp (check_mi_thread_command_set): Adapt
        =thread-select-event check.

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