[RFC]: Improvement of TUI status line to display pid and thread instead of target name

[Stephane Carrez <stephane dot carrez at gmail dot com>]

Hi!

While debugging a multi-thread application, the TUI status line looks
as follows:

multi-thre Thread 0xb7175 In:
system__tasking__rendezvous__timed_task_entry_call
Line: ??   PC: 0xb7d49787

The target name and thread information are not useful at all.
I've worked on a better status line which displays the process id, the
current thread id
and the number of threads.  The new status line looks as follows:

Pid 25932 Tid 1 on 7 In:
system__tasking__rendezvous__timed_task_entry_call
  Line: ??   PC: 0xb7d49787

I've also used the thread observer to be notified when a thread is
created or exited
so the status line is refreshed while threads are created/exited.

Attached is the patch for the above changes.

Before committing it, I would like your feedback.

Stephane

Index: ChangeLog
===================================================================
RCS file: /cvs/src/src/gdb/ChangeLog,v
retrieving revision 1.14812
diff -u -p -r1.14812 ChangeLog
--- ChangeLog	10 Nov 2012 13:12:17 -0000	1.14812
+++ ChangeLog	10 Nov 2012 17:41:48 -0000
@@ -1,5 +1,15 @@
 2012-11-10  Stephane Carrez  <Stephane.Carrez@gmail.com>
 
+	* tui/tui-data.h (MAX_PID_WIDTH): Increase to 24.
+	* tui/tui-stack.c (tui_make_status_line): Display the
+	current process and thread id instead of target name.
+	* tui/tui-hooks.c (tui_thread_exit): New function.
+	(tui_new_thread): Likewise.
+	(tui_install_hooks): Install the thread observers.
+	(tui_remove_hooks): And remove them here.
+
+2012-11-10  Stephane Carrez  <Stephane.Carrez@gmail.com>
+
 	* tui/tui.c (tui_rl_command_key): Switch to TUI_ONE_COMMAND_MODE
 	while executing the gdb command.
 	(tui_rl_startup_hook): Do not switch back to TUI_SINGLE_KEY_MODE if we
Index: tui/tui-data.h
===================================================================
RCS file: /cvs/src/src/gdb/tui/tui-data.h,v
retrieving revision 1.29
diff -u -p -r1.29 tui-data.h
--- tui/tui-data.h	1 Mar 2012 21:08:07 -0000	1.29
+++ tui/tui-data.h	10 Nov 2012 17:41:48 -0000
@@ -86,7 +86,7 @@ struct tui_gen_win_info
 				   numbers.  */
 #define MIN_PROC_WIDTH    12
 #define MAX_TARGET_WIDTH  10
-#define MAX_PID_WIDTH     14
+#define MAX_PID_WIDTH     24
 
 #define TUI_FLOAT_REGS_NAME                  "$FREGS"
 #define TUI_FLOAT_REGS_NAME_LOWER            "$fregs"
Index: tui/tui-hooks.c
===================================================================
RCS file: /cvs/src/src/gdb/tui/tui-hooks.c,v
retrieving revision 1.50
diff -u -p -r1.50 tui-hooks.c
--- tui/tui-hooks.c	8 Nov 2012 22:54:11 -0000	1.50
+++ tui/tui-hooks.c	10 Nov 2012 17:41:48 -0000
@@ -181,6 +181,22 @@ tui_about_to_proceed (void)
   tui_target_has_run = 1;
 }
 
+/* Handle thread exit.  Refresh the status line.  */
+
+static void
+tui_thread_exit (struct thread_info *tp, int silent)
+{
+  tui_show_locator_content ();
+}
+
+/* Handle thread creation.  Refresh the status line.  */
+
+static void
+tui_new_thread (struct thread_info *tp)
+{
+  tui_show_locator_content ();
+}
+
 /* The selected frame has changed.  This is happens after a target
    stop or when the user explicitly changes the frame
    (up/down/thread/...).  */
@@ -253,6 +269,8 @@ static struct observer *tui_bp_deleted_o
 static struct observer *tui_bp_modified_observer;
 static struct observer *tui_inferior_exit_observer;
 static struct observer *tui_about_to_proceed_observer;
+static struct observer *tui_thread_exit_observer;
+static struct observer *tui_new_thread_observer;
 
 /* Install the TUI specific hooks.  */
 void
@@ -276,6 +294,10 @@ tui_install_hooks (void)
     = observer_attach_inferior_exit (tui_inferior_exit);
   tui_about_to_proceed_observer
     = observer_attach_about_to_proceed (tui_about_to_proceed);
+  tui_thread_exit_observer
+    = observer_attach_thread_exit (tui_thread_exit);
+  tui_new_thread_observer
+    = observer_attach_new_thread (tui_new_thread);
 
   deprecated_register_changed_hook = tui_register_changed_hook;
 }
@@ -300,6 +322,10 @@ tui_remove_hooks (void)
   tui_inferior_exit_observer = NULL;
   observer_detach_about_to_proceed (tui_about_to_proceed_observer);
   tui_about_to_proceed_observer = NULL;
+  observer_detach_thread_exit (tui_thread_exit_observer);
+  tui_thread_exit_observer = NULL;
+  observer_detach_new_thread (tui_new_thread_observer);
+  tui_new_thread_observer = NULL;
 }
 
 void _initialize_tui_hooks (void);
Index: tui/tui-stack.c
===================================================================
RCS file: /cvs/src/src/gdb/tui/tui-stack.c,v
retrieving revision 1.46
diff -u -p -r1.46 tui-stack.c
--- tui/tui-stack.c	25 Apr 2012 08:16:43 -0000	1.46
+++ tui/tui-stack.c	10 Nov 2012 17:41:48 -0000
@@ -29,6 +29,7 @@
 #include "top.h"
 #include "gdb-demangle.h"
 #include "gdb_string.h"
+#include "gdbthread.h"
 #include "tui/tui.h"
 #include "tui/tui-data.h"
 #include "tui/tui-stack.h"
@@ -57,8 +58,8 @@ static void tui_update_command (char *, 
 
 
 /* Create the status line to display as much information as we can on
-   this single line: target name, process number, current function,
-   current line, current PC, SingleKey mode.  */
+   this single line: target name, process number, thread id, thread count,
+   current function, current line, current PC, SingleKey mode.  */
 static char*
 tui_make_status_line (struct tui_locator_element *loc)
 {
@@ -74,16 +75,31 @@ tui_make_status_line (struct tui_locator
   int line_width;
   int pc_width;
   struct ui_file *pc_out;
+  char proc_info[40];
+
+  target_width = strlen (target_shortname);
+  if (target_width > MAX_TARGET_WIDTH)
+    target_width = MAX_TARGET_WIDTH;
 
   if (ptid_equal (inferior_ptid, null_ptid))
     pid_name = "No process";
   else
-    pid_name = target_pid_to_str (inferior_ptid);
+    {
+      int nr_threads = thread_count ();
 
-  target_width = strlen (target_shortname);
-  if (target_width > MAX_TARGET_WIDTH)
-    target_width = MAX_TARGET_WIDTH;
+      if (nr_threads > 1)
+        xsnprintf (proc_info, sizeof (proc_info), "Pid %d Tid %d on %d",
+                   ptid_get_pid (inferior_ptid),
+                   pid_to_thread_id (inferior_ptid),
+                   nr_threads);
+      else
+        xsnprintf (proc_info, sizeof (proc_info), "Pid %d",
+                   ptid_get_pid (inferior_ptid));
 
+      target_width = 0;
+      pid_name = proc_info;
+    }
+  
   pid_width = strlen (pid_name);
   if (pid_width > MAX_PID_WIDTH)
     pid_width = MAX_PID_WIDTH;