[PATCH v3 0/3] Suppressing CLI notifications

[PATCH v3 0/3] Suppressing CLI notifications

[Tankut Baris Aktemur]

Hello,

This is a small series about suppressing CLI notifications.  The first
revision is available at

  https://sourceware.org/pipermail/gdb-patches/2021-December/184008.html

The second revision is at

  https://sourceware.org/pipermail/gdb-patches/2022-January/185320.html

In Revision v3:

  * Patch 1/3 is omitted (already approved in v1).
  * Patch 2/3 is omitted (already approved in v1).
  * Patch 3/3 is updated to address Andrew's comments at

    https://sourceware.org/pipermail/gdb-patches/2022-February/185656.html

Regards
Baris

Tankut Baris Aktemur (3):
  gdb/cli: convert cli_suppress_notification from int to bool
  gdb/cli: add a 'normal_stop' option to 'cli_suppress_notification'
  gdb: add the 'set/show suppress-notification-cli' command

 gdb/NEWS                                      |   5 +
 gdb/cli/cli-cmds.c                            |  39 ++++++
 gdb/cli/cli-decode.c                          |  10 +-
 gdb/cli/cli-decode.h                          |   2 +-
 gdb/cli/cli-interp.c                          |   9 +-
 gdb/command.h                                 |  11 +-
 gdb/doc/gdb.texinfo                           | 121 ++++++++++++++++++
 .../gdb.base/cli-suppress-notification.c      |  26 ++++
 .../gdb.base/cli-suppress-notification.exp    |  39 ++++++
 gdb/tui/tui-interp.c                          |   4 +
 10 files changed, 252 insertions(+), 14 deletions(-)
 create mode 100644 gdb/testsuite/gdb.base/cli-suppress-notification.c
 create mode 100644 gdb/testsuite/gdb.base/cli-suppress-notification.exp

-- 
2.33.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v3 3/3] gdb: add the 'set/show suppress-notification-cli' command

[Tankut Baris Aktemur]

GDB already has a flag to suppress printing notification events, such
as thread and inferior context switches, on the CLI.  This is used
internally when executing commands.  Make the flag available to the
user via a new command.  This is expected to be useful in scripts.

For instance, suppose that when Inferior 1 gets to a certain state,
you want to add and set up a new inferior using the commands below,
but you also want to have a reduced/clean output.

  define do-setup
    printf "Setting up Inferior 2...\n"
    add-inferior -exec a.out
    inferior 2
    break file.c:3
    run
    inferior 1
    printf "Done\n"
  end

Currently, GDB prints

  (gdb) do-setup
  Setting up Inferior 2...
  [New inferior 2]
  Added inferior 2 on connection 1 (native)
  [Switching to inferior 2 [<null>] (/tmp/a.out)]
  Breakpoint 2 at 0x1155: file file.c, line 3.

  Thread 2.1 "a.out" hit Breakpoint 2, main () at file.c:3
  3         return 0;
  [Switching to inferior 1 [process 7670] (/tmp/test)]
  [Switching to thread 1.1 (process 7670)]
  #0  main () at test.c:2
  2         int a = 1;
  Done

GDB's Python API make it possible to capture and return GDB's output,
but this does not work for all the streams.  In particular, CLI
notification events are not captured:

  (gdb) python gdb.execute("do-setup", False, True)
  [Switching to inferior 2 [<null>] (/tmp/a.out)]

  Thread 2.1 "a.out" hit Breakpoint 2, main () at file.c:3
  3         return 0;
  [Switching to inferior 1 [process 8263] (/tmp/test)]
  [Switching to thread 1.1 (process 8263)]
  #0  main () at test.c:2
  2         int a = 1;

You can use the new "set suppress-notification-cli" command to
suppress the output:

  (gdb) set suppress-notification-cli on
  (gdb) do-setup
  Setting up Inferior 2...
  [New inferior 2]
  Added inferior 2 on connection 1 (native)
  Breakpoint 2 at 0x1155: file file.c, line 3.
  Done
---
 gdb/NEWS                                      |   5 +
 gdb/cli/cli-cmds.c                            |  39 ++++++
 gdb/doc/gdb.texinfo                           | 121 ++++++++++++++++++
 .../gdb.base/cli-suppress-notification.c      |  26 ++++
 .../gdb.base/cli-suppress-notification.exp    |  39 ++++++
 5 files changed, 230 insertions(+)
 create mode 100644 gdb/testsuite/gdb.base/cli-suppress-notification.c
 create mode 100644 gdb/testsuite/gdb.base/cli-suppress-notification.exp

diff --git a/gdb/NEWS b/gdb/NEWS
index e1900596ca7..1e11b49aedd 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -81,6 +81,11 @@ maint show gnu-source-highlight enabled
   styling to a particular source file, then the Python Pygments
   library will be used instead.
 
+set suppress-notification-cli (on|off)
+show suppress-notification-cli
+  This controls whether printing the notification events is suppressed
+  for CLI.
+
 * Changed commands
 
 maint packet
diff --git a/gdb/cli/cli-cmds.c b/gdb/cli/cli-cmds.c
index 1d14b8e4527..18c8c293f47 100644
--- a/gdb/cli/cli-cmds.c
+++ b/gdb/cli/cli-cmds.c
@@ -192,6 +192,11 @@ static const char *const script_ext_enums[] = {
 
 static const char *script_ext_mode = script_ext_soft;
 \f
+
+/* User-controllable flag to suppress event notification on CLI.  */
+
+static bool user_wants_cli_suppress_notification = false;
+
 /* Utility used everywhere when at least one argument is needed and
    none is supplied.  */
 
@@ -2136,6 +2141,28 @@ show_max_user_call_depth (struct ui_file *file, int from_tty,
 		    value);
 }
 
+/* Implement 'show suppress-notification-cli'.  */
+
+static void
+show_suppress_notification_cli (ui_file *file, int from_tty,
+				cmd_list_element *c, const char *value)
+{
+  fprintf_filtered (file, _("Suppression of printing CLI notification events "
+			    "is %s.\n"), value);
+}
+
+/* Implement 'set suppress-notification-cli'.  */
+
+static void
+set_suppress_notification_cli (const char *args, int from_tty,
+			       cmd_list_element *c)
+{
+  cli_suppress_notification.user_selected_context
+    = user_wants_cli_suppress_notification;
+  cli_suppress_notification.normal_stop
+    = user_wants_cli_suppress_notification;
+}
+
 /* Returns the cmd_list_element in SHOWLIST corresponding to the first
    argument of ARGV, which must contain one single value.
    Throws an error if no value provided, or value not correct.
@@ -2734,6 +2761,18 @@ Make \"wLapPeu\" an alias of 2 nested \"with\":\n\
 
   set_cmd_completer_handle_brkchars (c, alias_command_completer);
 
+  add_setshow_boolean_cmd ("suppress-notification-cli", no_class,
+			   &user_wants_cli_suppress_notification,
+			   _("\
+Set whether printing notification events on CLI is suppressed."), _("\
+Show whether printing notification events on CLI is suppressed."), _("\
+When on, printing notification events (such as inferior/thread switch)\n\
+on CLI is suppressed."),
+			   set_suppress_notification_cli,
+			   show_suppress_notification_cli,
+			   &setlist,
+			   &showlist);
+
   const char *source_help_text = xstrprintf (_("\
 Read commands from a file named FILE.\n\
 \n\
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index fe81687a66c..fadde0eec7f 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -27211,6 +27211,127 @@ inside a cygwin window.
 Displays whether the debugger is operating in interactive mode or not.
 @end table
 
+@table @code
+@kindex set suppress-notification-cli
+@item set suppress-notification-cli
+If @code{on}, command-line-interface (CLI) notification events that
+are printed by @value{GDBN} are suppressed.  If @code{off}, the
+notification events are printed as usual.  The default value is
+@code{off}.  The CLI notification events occur when you change the
+selected context or when the program being debugged stops, as detailed
+below.
+
+@noindent
+@emph{User-selected context changes:} When you change the selected
+context (i.e.@:  the current inferior, thread and/or the frame),
+@value{GDBN} prints information about the new context.  For example,
+the default behavior is below:
+
+@smallexample
+(gdb) inferior 1
+[Switching to inferior 1 [process 634] (/tmp/test)]
+[Switching to thread 1 (process 634)]
+#0  main () at test.c:3
+3         return 0;
+(gdb)
+@end smallexample
+
+@noindent
+When the events are suppressed, the new context is not printed:
+
+@smallexample
+(gdb) set suppress-notification-cli on
+(gdb) inferior 1
+(gdb)
+@end smallexample
+
+@noindent
+@emph{The program being debugged stops:} When the program you are
+debugging stops (e.g.@: because of hitting a breakpoint, completing
+source-stepping, an interrupt, etc.), @value{GDBN} prints information
+about the stop event.  For example, below is a breakpoint hit event:
+
+@smallexample
+(gdb) break test.c:3
+Breakpoint 2 at 0x555555555155: file test.c, line 3.
+(gdb) continue
+Continuing.
+
+Breakpoint 2, main () at test.c:3
+3         return 0;
+(gdb)
+@end smallexample
+
+@noindent
+When the events are suppressed, the output becomes:
+
+@smallexample
+(gdb) break test.c:3
+Breakpoint 2 at 0x555555555155: file test.c, line 3.
+(gdb) set suppress-notification-cli on
+(gdb) continue
+Continuing.
+(gdb)
+@end smallexample
+
+@noindent
+Suppressing CLI notification events may be useful in scripts to obtain
+a reduced output from a list of commands.  For instance, suppose that
+you want to add and set up a new inferior using the following
+commands:
+
+@smallexample
+define do-setup
+  printf "Setting up Inferior 2...\n"
+  add-inferior -exec a.out
+  inferior 2
+  break file.c:3
+  run
+  inferior 1
+  printf "Done\n"
+end
+@end smallexample
+
+@noindent
+When the CLI notification events are not suppressed, the output is as
+follows:
+
+@smallexample
+(gdb) do-setup
+Setting up Inferior 2...
+[New inferior 2]
+Added inferior 2 on connection 1 (native)
+[Switching to inferior 2 [<null>] (/tmp/a.out)]
+Breakpoint 2 at 0x1155: file file.c, line 3.
+
+Thread 2.1 "a.out" hit Breakpoint 2, main () at file.c:3
+3         return 0;
+[Switching to inferior 1 [process 5714] (/tmp/test)]
+[Switching to thread 1.1 (process 5714)]
+#0  main () at test.c:2
+2         int a = 1;
+Done
+@end smallexample
+
+@noindent
+When suppressed, the output becomes
+
+@smallexample
+(gdb) set suppress-notification-cli on
+(gdb) do-setup
+Setting up Inferior 2...
+[New inferior 2]
+Added inferior 2 on connection 1 (native)
+Breakpoint 2 at 0x1155: file file.c, line 3.
+Done
+@end smallexample
+
+@kindex show suppress-notification-cli
+@item show suppress-notification-cli
+Displays whether printing CLI notification events is suppressed or
+not.
+@end table
+
 @node Extending GDB
 @chapter Extending @value{GDBN}
 @cindex extending GDB
diff --git a/gdb/testsuite/gdb.base/cli-suppress-notification.c b/gdb/testsuite/gdb.base/cli-suppress-notification.c
new file mode 100644
index 00000000000..243dbc9c70a
--- /dev/null
+++ b/gdb/testsuite/gdb.base/cli-suppress-notification.c
@@ -0,0 +1,26 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2020-2022 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+static int global = 0;
+
+int
+main ()
+{
+  global++;
+  global++;
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.base/cli-suppress-notification.exp b/gdb/testsuite/gdb.base/cli-suppress-notification.exp
new file mode 100644
index 00000000000..91efd8ebe36
--- /dev/null
+++ b/gdb/testsuite/gdb.base/cli-suppress-notification.exp
@@ -0,0 +1,39 @@
+# Copyright 2020-2022 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Test the cli-suppress-notification command.
+
+standard_testfile
+
+if {[prepare_for_testing "failed to prepare" ${binfile} ${srcfile}]} {
+    return
+}
+
+if {![runto_main]} {
+    return
+}
+
+gdb_test "inferior 1" ".*Switching to inferior 1 .* to thread 1 .*" \
+    "inferior switch is not suppressed"
+
+gdb_test_no_output "set suppress-notification-cli on"
+gdb_test_no_output "inferior 1" "inferior switch is suppressed"
+gdb_test_no_output "next" "stepping is suppressed"
+
+# Now check that suppression can be turned back off.
+gdb_test_no_output "set suppress-notification-cli off"
+gdb_test "inferior 1" ".*Switching to inferior 1 .* to thread 1 .*" \
+    "inferior switch is not suppressed again"
+gdb_test "next" "return 0;" "stepping is not suppressed"
-- 
2.33.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

Re: [PATCH v3 3/3] gdb: add the 'set/show suppress-notification-cli' command

[Eli Zaretskii]

> From: Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
> Cc: aburgess@redhat.com,
> 	tom@tromey.com,
> 	eliz@gnu.org
> Date: Thu,  3 Feb 2022 09:30:41 +0100
> 
> +set suppress-notification-cli (on|off)
> +show suppress-notification-cli
> +  This controls whether printing the notification events is suppressed
> +  for CLI.

I think suppress-cli-notifications is a better name for this setting.

Also, I think NEWS should explain a bit what is mean by
"notifications" here.  The "events" part should be removed, since you
don't really "print events", right?

> +@noindent
> +@emph{User-selected context changes:} When you change the selected
> +context (i.e.@:  the current inferior, thread and/or the frame),
> +@value{GDBN} prints information about the new context.  For example,
> +the default behavior is below:
> +
> +@smallexample
> +(gdb) inferior 1
> +[Switching to inferior 1 [process 634] (/tmp/test)]
> +[Switching to thread 1 (process 634)]
> +#0  main () at test.c:3
> +3         return 0;
> +(gdb)
> +@end smallexample
> +
> +@noindent
> +When the events are suppressed, the new context is not printed:
> +
> +@smallexample
> +(gdb) set suppress-notification-cli on
> +(gdb) inferior 1
> +(gdb)
> +@end smallexample
> +
> +@noindent
> +@emph{The program being debugged stops:} When the program you are
> +debugging stops (e.g.@: because of hitting a breakpoint, completing
> +source-stepping, an interrupt, etc.), @value{GDBN} prints information
> +about the stop event.  For example, below is a breakpoint hit event:

This would be better formatted as a @table, I think.

> +@noindent
> +Suppressing CLI notification events may be useful in scripts to obtain
> +a reduced output from a list of commands.  For instance, suppose that
> +you want to add and set up a new inferior using the following
> +commands:
> +
> +@smallexample
> +define do-setup
> +  printf "Setting up Inferior 2...\n"
> +  add-inferior -exec a.out
> +  inferior 2
> +  break file.c:3
> +  run
> +  inferior 1
> +  printf "Done\n"
> +end
> +@end smallexample
> +
> +@noindent
> +When the CLI notification events are not suppressed, the output is as
> +follows:
> +
> +@smallexample
> +(gdb) do-setup
> +Setting up Inferior 2...
> +[New inferior 2]
> +Added inferior 2 on connection 1 (native)
> +[Switching to inferior 2 [<null>] (/tmp/a.out)]
> +Breakpoint 2 at 0x1155: file file.c, line 3.
> +
> +Thread 2.1 "a.out" hit Breakpoint 2, main () at file.c:3
> +3         return 0;
> +[Switching to inferior 1 [process 5714] (/tmp/test)]
> +[Switching to thread 1.1 (process 5714)]
> +#0  main () at test.c:2
> +2         int a = 1;
> +Done
> +@end smallexample
> +
> +@noindent
> +When suppressed, the output becomes
> +
> +@smallexample
> +(gdb) set suppress-notification-cli on
> +(gdb) do-setup
> +Setting up Inferior 2...
> +[New inferior 2]
> +Added inferior 2 on connection 1 (native)
> +Breakpoint 2 at 0x1155: file file.c, line 3.
> +Done
> +@end smallexample
> +
> +@kindex show suppress-notification-cli
> +@item show suppress-notification-cli
> +Displays whether printing CLI notification events is suppressed or
> +not.
> +@end table

The example part here is too long, and doesn't really say anything
new.  So I would delete it, leaving just the note explaining when and
why this would be useful.

Thanks, the documentation parts are OK with these nits fixed.