[RFA] 'set print thread-events' to control printing of thread start/exit messages

[RFA] 'set print thread-events' to control printing of thread start/exit messages

[Chris Demetriou]

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[hi!  long time no see!]

The attached patch makes the printing of thread start/exit messages on
Linux configurable via 'set print thread-events'.  (A coworker
commented that for the benchmarks he was trying to debug, printing of
thread start/exit messages was ... quite tedious.  And i figured a
patch would be ... quite straightforward.)

I'm ambivalent about the name of the new option, and the location of
the option in the docs.  I'm willing to listen to suggestions
(especially from approvers! 8-) of better alternatives.


Built w/ gdb head sources as of 2007-12-19 mid-day (US/Pacific),
configured w/ host/target/build=i686-linux, tested with the new test
("make RUNTESTFLAGS=thread_events.exp") + using "info .../gdb.info" to
view the new docs.




chris
----
[gdb/ChangeLog]
2007-12-19  Chris Demetriou  <cgd@google.com>

        * gdbthread.h (print_thread_events): New variable declaration.
        * thread.c (print_thread_events): New variable definition.
        (show_print_thread_events): New function.
        (_initialize_thread): Add "set print thread-events" and
        "show print thread-events" commands.
        * linux-thread-db.c (check_event): Make attach_thread and
        detach_thread be verbose only if print_thread_events is set.

[gdb/doc/ChangeLog]
2007-12-19  Chris Demetriou  <cgd@google.com>

        * gdb.texinfo (Threads): Document new "set print thread-events"
        and "show print thread-events" commands.

[gdb/testsuite/ChangeLog]
2007-12-19  Chris Demetriou  <cgd@google.com>

        * gdb.threads/thread_events.c: New testcase source file.
        * gdb.threads/thread_events.exp: New testcase expect file.

[-- Attachment #2: gdb_thread_event_messages.patch --]
[-- Type: application/octet-stream, Size: 11735 bytes --]

[gdb/ChangeLog]
2007-12-19  Chris Demetriou  <cgd@google.com>

        * gdbthread.h (print_thread_events): New variable declaration.
        * thread.c (print_thread_events): New variable definition.
        (show_print_thread_events): New function.
        (_initialize_thread): Add "set print thread-events" and
        "show print thread-events" commands.
        * linux-thread-db.c (check_event): Make attach_thread and
        detach_thread be verbose only if print_thread_events is set.

[gdb/doc/ChangeLog]
2007-12-19  Chris Demetriou  <cgd@google.com>

        * gdb.texinfo (Threads): Document new "set print thread-events"
        and "show print thread-events" commands.

[gdb/testsuite/ChangeLog]
2007-12-19  Chris Demetriou  <cgd@google.com>

        * gdb.threads/thread_events.c: New testcase source file.
        * gdb.threads/thread_events.exp: New testcase expect file.


Index: gdbthread.h
===================================================================
RCS file: /cvs/src/src/gdb/gdbthread.h,v
retrieving revision 1.17
diff -u -u -p -r1.17 gdbthread.h
--- gdbthread.h	6 Dec 2007 12:57:51 -0000	1.17
+++ gdbthread.h	20 Dec 2007 00:05:56 -0000
@@ -141,4 +141,8 @@ extern void switch_to_thread (ptid_t pti
 /* Commands with a prefix of `thread'.  */
 extern struct cmd_list_element *thread_cmd_list;
 
+/* Print notices on thread events (attach, detach, etc.), set with
+   `set print thread-events'.  */
+extern int print_thread_events;
+
 #endif /* GDBTHREAD_H */
Index: linux-thread-db.c
===================================================================
RCS file: /cvs/src/src/gdb/linux-thread-db.c,v
retrieving revision 1.35
diff -u -u -p -r1.35 linux-thread-db.c
--- linux-thread-db.c	25 Oct 2007 22:09:34 -0000	1.35
+++ linux-thread-db.c	20 Dec 2007 00:05:56 -0000
@@ -843,7 +843,7 @@ check_event (ptid_t ptid)
 	case TD_CREATE:
 	  /* Call attach_thread whether or not we already know about a
 	     thread with this thread ID.  */
-	  attach_thread (ptid, msg.th_p, &ti, 1);
+	  attach_thread (ptid, msg.th_p, &ti, print_thread_events);
 
 	  break;
 
@@ -852,7 +852,7 @@ check_event (ptid_t ptid)
 	  if (!in_thread_list (ptid))
 	    error (_("Spurious thread death event."));
 
-	  detach_thread (ptid, 1);
+	  detach_thread (ptid, print_thread_events);
 
 	  break;
 
Index: thread.c
===================================================================
RCS file: /cvs/src/src/gdb/thread.c,v
retrieving revision 1.57
diff -u -u -p -r1.57 thread.c
--- thread.c	6 Dec 2007 12:57:51 -0000	1.57
+++ thread.c	20 Dec 2007 00:05:56 -0000
@@ -675,6 +675,17 @@ thread_command (char *tidstr, int from_t
   gdb_thread_select (uiout, tidstr, NULL);
 }
 
+/* Print notices when new threads are attached and detached.  */
+int print_thread_events = 1;
+static void
+show_print_thread_events (struct ui_file *file, int from_tty,
+                          struct cmd_list_element *c, const char *value)
+{
+  fprintf_filtered (file, _("\
+Printing of thread events is %s.\n"),
+                    value);
+}
+
 static int
 do_captured_thread_select (struct ui_out *uiout, void *tidstr)
 {
@@ -737,4 +748,12 @@ The new thread ID must be currently know
 
   if (!xdb_commands)
     add_com_alias ("t", "thread", class_run, 1);
+
+  add_setshow_boolean_cmd ("thread-events", no_class,
+         &print_thread_events, _("\
+Set printing of thread events (e.g., thread start and exit)."), _("\
+Show printing of thread events (e.g., thread start and exit)."), NULL,
+         NULL,
+         show_print_thread_events,
+         &setprintlist, &showprintlist);
 }
Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.453
diff -u -u -p -r1.453 gdb.texinfo
--- doc/gdb.texinfo	18 Dec 2007 18:11:09 -0000	1.453
+++ doc/gdb.texinfo	20 Dec 2007 00:05:56 -0000
@@ -2241,6 +2241,8 @@ programs:
 @item @samp{thread apply [@var{threadno}] [@var{all}] @var{args}},
 a command to apply a command to a list of threads
 @item thread-specific breakpoints
+@item @samp{set print thread-events}, which controls printing of 
+messages on thread start and exit.
 @end itemize
 
 @quotation
@@ -2434,6 +2436,22 @@ threads that you want affected with the 
 shown in the first field of the @samp{info threads} display; or it
 could be a range of thread numbers, as in @code{2-4}.  To apply a
 command to all threads, type @kbd{thread apply all @var{command}}.
+
+@kindex set print thread-events
+@cindex print messages on thread start and exit
+@item set print thread-events
+@itemx set print thread-events on
+@itemx set print thread-events off
+The @code{set print thread-attach} command allows you to enable or
+disable printing of messages when GDB notices that new threads have
+started or that threads have exited.  By default, these messages will
+be printed if detection of these events is supported by the target.
+Note that these messages cannot be disabled on all targets.
+
+@kindex show print thread-events
+@item show print thread-events
+Show whether messages will be printed when GDB detects that threads
+have started and exited.
 @end table
 
 @cindex automatic thread selection
Index: testsuite/gdb.threads/thread_events.c
===================================================================
RCS file: testsuite/gdb.threads/thread_events.c
diff -N testsuite/gdb.threads/thread_events.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.threads/thread_events.c	20 Dec 2007 00:05:56 -0000
@@ -0,0 +1,55 @@
+/* Copyright (C) 2007 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/>.
+
+   This file was written by Chris Demetriou (cgd@google.com).  */
+
+/* Simple test to trigger thread events (thread start, thread exit).  */
+
+#include <pthread.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+static void *
+threadfunc (void *arg)
+{
+  printf ("in threadfunc\n");
+  return NULL;
+}
+
+static void
+after_join_func (void)
+{
+  printf ("finished\n");
+}
+
+int main (int argc, char *argv[])
+{
+  pthread_t thread;
+
+  if (pthread_create(&thread, NULL, threadfunc, NULL) != 0)
+    {
+      printf ("pthread_create failed\n");
+      exit (1);
+    }
+
+  if (pthread_join (thread, NULL) != 0)
+    {
+      printf ("pthread_join failed\n");
+      exit (1);
+    }
+
+  after_join_func();
+  return 0;
+}
Index: testsuite/gdb.threads/thread_events.exp
===================================================================
RCS file: testsuite/gdb.threads/thread_events.exp
diff -N testsuite/gdb.threads/thread_events.exp
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.threads/thread_events.exp	20 Dec 2007 00:05:56 -0000
@@ -0,0 +1,149 @@
+# Copyright (C) 2007 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/>.
+
+# Please email any bugs, comments, and/or additions to this file to:
+# bug-gdb@prep.ai.mit.edu
+
+# This file was written by Chris Demetriou (cgd@google.com).
+# It tests printing of thread event (start, exit) information, and
+# disabling of those messages.
+#
+# Note: the format of thread event messages (and also whether or not
+# messages are printed and can be disabled) is dependent on the target
+# thread support code.
+
+# This test has only been verified with Linux targets, and would need
+# to be generalized to support other targets
+if ![istarget *-*-linux*] then {
+    return
+}
+
+if $tracelevel then {
+        strace $tracelevel
+}
+
+set prms_id 0
+set bug_id 0
+
+set testfile "thread_events"
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+
+if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable [list debug "incdir=${objdir}"]] != "" } {
+    return -1
+}
+
+proc gdb_test_thread_start {messages_enabled command pattern message} {
+  global gdb_prompt
+
+  if { $messages_enabled } {
+    set events_expected 1
+  } else {
+    set events_expected 0
+  }
+  set events_seen 0
+
+  return [gdb_test_multiple $command $message {
+    -re "\\\[New Thread \[^\]\]*\\\]\r\n" {
+      incr events_seen;
+      exp_continue;
+    }
+    -re "\[\r\n\]*($pattern)\[\r\n\]+$gdb_prompt $" {
+      if { $events_seen != $events_expected } {
+        fail "$message (saw $events_seen, expected $events_expected)"
+      } else {
+        pass "$message"
+      }
+    }
+  }]
+}
+
+proc gdb_test_thread_exit {messages_enabled command pattern message} {
+  global gdb_prompt
+
+  if { $messages_enabled } {
+    set events_expected 1
+  } else {
+    set events_expected 0
+  }
+  set events_seen 0
+
+  return [gdb_test_multiple $command $message {
+    -re "\\\[Thread \[^\]\]* exited\\\]\r\n" {
+      incr events_seen
+      exp_continue;
+    }
+    -re "\[\r\n\]*($pattern)\[\r\n\]+$gdb_prompt $" {
+      if { $events_seen != $events_expected } {
+        fail "$message (saw $events_seen, expected $events_expected)"
+      } else {
+        pass "$message"
+      }
+    }
+  }]
+}
+
+proc test_thread_messages {enabled} {
+  global srcdir subdir binfile srcfile
+
+  if { $enabled } {
+    set enabled_string "with messages enabled"
+  } else {
+    set enabled_string "with messages disabled"
+  }
+
+  gdb_start
+  gdb_reinitialize_dir $srcdir/$subdir
+  gdb_load ${binfile}
+
+  if { $enabled } {
+     gdb_test "set print thread-events on"
+  } else {
+     gdb_test "set print thread-events off"
+  }
+
+  # The initial thread may log a 'New Thread' message, but we don't
+  # check for it.
+  if ![runto_main] then {
+     fail "Can't run to main $enabled_string"
+     return 1
+  }
+
+  gdb_test "break threadfunc" \
+      "Breakpoint.*at.* file .*$srcfile, line.*" \
+      "breakpoint at threadfunc $enabled_string"
+  gdb_test "break after_join_func" \
+      "Breakpoint.*at.* file .*$srcfile, line.*" \
+      "breakpoint at after_join_func $enabled_string"
+
+  # continue to threadfunc breakpoint.  A thread will start.
+  # Expect to see a thread start message, if messages are enabled.
+  gdb_test_thread_start $enabled "continue" \
+       ".*Breakpoint .*,.*threadfunc.*at.*$srcfile:.*" \
+       "continue to threadfunc $enabled_string"
+
+  # continue to after_join_func breakpoint.  A thread will exit.
+  # Expect to see a thread exit message, if messages are enabled.
+  gdb_test_thread_exit $enabled "continue" \
+       ".*Breakpoint .*,.*after_join_func.*at.*$srcfile:.*" \
+       "continue to after_join_func $enabled_string"
+
+  delete_breakpoints
+
+  gdb_exit
+}
+
+test_thread_messages 0
+test_thread_messages 1

Re: [RFA] 'set print thread-events' to control printing of thread start/exit messages

[Daniel Jacobowitz]

On Thu, Dec 20, 2007 at 12:03:17AM -0800, Chris Demetriou wrote:
> [hi!  long time no see!]

No kidding!

> The attached patch makes the printing of thread start/exit messages on
> Linux configurable via 'set print thread-events'.  (A coworker
> commented that for the benchmarks he was trying to debug, printing of
> thread start/exit messages was ... quite tedious.  And i figured a
> patch would be ... quite straightforward.)
> 
> I'm ambivalent about the name of the new option, and the location of
> the option in the docs.  I'm willing to listen to suggestions
> (especially from approvers! 8-) of better alternatives.

Hi Chris, meet Vladimir.  Hi Vladimir, meet Chris.  I suggest one of
you combine this with Vladimir's recently pending patch to unify new
thread printing in a single place for all targets.

BTW, the new test would fail for GNU/Linux + gdbserver; that doesn't
yet have any way to notify new threads, unlike the native support.

-- 
Daniel Jacobowitz
CodeSourcery

Re: [RFA] 'set print thread-events' to control printing of thread start/exit messages

[Vladimir Prus]

On Thursday 20 December 2007 16:45:56 Daniel Jacobowitz wrote:
> On Thu, Dec 20, 2007 at 12:03:17AM -0800, Chris Demetriou wrote:
> > [hi!  long time no see!]
> 
> No kidding!
> 
> > The attached patch makes the printing of thread start/exit messages on
> > Linux configurable via 'set print thread-events'.  (A coworker
> > commented that for the benchmarks he was trying to debug, printing of
> > thread start/exit messages was ... quite tedious.  And i figured a
> > patch would be ... quite straightforward.)
> > 
> > I'm ambivalent about the name of the new option, and the location of
> > the option in the docs.  I'm willing to listen to suggestions
> > (especially from approvers! 8-) of better alternatives.
> 
> Hi Chris, meet Vladimir.  Hi Vladimir, meet Chris.  

Hi Chris!

> I suggest one of 
> you combine this with Vladimir's recently pending patch to unify new
> thread printing in a single place for all targets.

I can do this, if Chris does not mind.

- Volodya

Re: [RFA] 'set print thread-events' to control printing of thread start/exit messages

[Chris Demetriou]

On Dec 20, 2007 7:23 AM, Vladimir Prus <vladimir@codesourcery.com> wrote:
> On Thursday 20 December 2007 16:45:56 Daniel Jacobowitz wrote:
> > I suggest one of
> > you combine this with Vladimir's recently pending patch to unify new
> > thread printing in a single place for all targets.
>
> I can do this, if Chris does not mind.

Absolutely fine w/ me.  ("Less work for me!  Yay!"  8-)


thanks,

chris

Re: [RFA] 'set print thread-events' to control printing of thread start/exit messages

[Eli Zaretskii]

> Date: Thu, 20 Dec 2007 00:03:17 -0800
> From: "Chris Demetriou" <cgd@google.com>
> 
> The attached patch makes the printing of thread start/exit messages on
> Linux configurable via 'set print thread-events'.

Thanks.

> +@kindex set print thread-events
> +@cindex print messages on thread start and exit
> +@item set print thread-events
> +@itemx set print thread-events on
> +@itemx set print thread-events off
> +The @code{set print thread-attach} command allows you to enable or

Is it "thread-events" or "thread-attach"?

> +disable printing of messages when GDB notices that new threads have

Please use "@value{GDBN}" instead of a literal "GDB".

Other than these gotchas, the patch for gdb.texinfo is approved.