gdb: Rework command completion on 'tui reg'.

We previously specified a few known register groups for the 'tui reg'
command.  Other register groups could be accessed, but only by using the
'tui reg next' command and cycling through all the groups.

This commit removes the hard coded sub-commands of 'tui reg' and instead
adds dynamic completion of sub-commands based on the architecturally
defined register groups, giving immediate access to all available
register groups.

There is still the 'next' and 'prev' commands for cycling through the
register groups if that's wanted.

The new code maintains the ability to only enter partial names for
register groups, which is something we got for free when using the
standard sub-command mechanism.

The register (and register group) completer has been changed to use
get_current_arch rather than using the architecture of the currently
selected frame.  When the target is running, this is equivalent,
however, when the target is not running, using get_current_arch will
provide results from the default architecture.

gdb/ChangeLog:

	* completer.c: Add arch-utils.h include.
	(enum reg_completer_targets): New enum.
	(reg_or_group_completer_1): New function containing old
	reg_or_group_completer, add and use new parameter to control what
	is completed on.  Use get_current_arch rather than architecture of
	currently selected frame.
	(reg_or_group_completer): Call new reg_or_group_completer_1.
	(reggroup_completer): Call new reg_or_group_completer_1.
	* completer.h (reggroup_completer): Add declaration.
	* tui/tui-regs.c: Add 'completer.h' include.
	(tui_reg_next_command): Renamed to...
	(tui_reg_next): ...this.  Adjust parameters and return rather than
	display new group.
	(tui_reg_prev_command): Renamed to...
	(tui_reg_prev): ...this.  Adjust parameters and return rather than
	display new group.
	(tui_reg_float_command): Delete.
	(tui_reg_general_command): Delete.
	(tui_reg_system_command): Delete.
	(tui_reg_command): Rewrite to perform switching of register group.
	Add header comment.
	(tuireglist): Remove.
	(tui_reggroup_completer): New function.
	(_initialize_tui_regs): Remove 'tui reg' sub-commands, update
	creation of 'tui reg' command.
	* NEWS: Add comment about 'tui reg' changes.

gdb/doc/ChangeLog:

	* gdb.texinfo (TUI Commands): Bring all 'tui reg' commands into a
	single table entry.

1 files changed, 105 insertions, 60 deletions

diff --git a/gdb/tui/tui-regs.c b/gdb/tui/tui-regs.c
index 6ac3c2b..a61fadb 100644
--- a/gdb/tui/tui-regs.c
+++ b/gdb/tui/tui-regs.c
@@ -39,6 +39,7 @@
 #include "tui/tui-io.h"
 #include "reggroups.h"
 #include "valprint.h"
+#include "completer.h"
 
 #include "gdb_curses.h"
 
@@ -556,74 +557,135 @@ tui_display_register (struct tui_data_element *data,
     }
 }
 
-static void
-tui_reg_next_command (char *arg, int from_tty)
+/* Helper for "tui reg next", wraps a call to REGGROUP_NEXT, but adds wrap
+   around behaviour.  Returns the next register group, or NULL if the
+   register window is not currently being displayed.  */
+
+static struct reggroup *
+tui_reg_next (struct gdbarch *gdbarch)
 {
-  struct gdbarch *gdbarch = get_current_arch ();
+  struct reggroup *group = NULL;
 
   if (TUI_DATA_WIN != NULL)
     {
-      struct reggroup *group
-        = TUI_DATA_WIN->detail.data_display_info.current_group;
-
+      group = TUI_DATA_WIN->detail.data_display_info.current_group;
       group = reggroup_next (gdbarch, group);
       if (group == NULL)
         group = reggroup_next (gdbarch, NULL);
-
-      if (group != NULL)
-        tui_show_registers (group);
     }
+  return group;
 }
 
-/* Implementation of the "tui reg prev" command.  Cycle the register group
-   displayed in the tui REG window, moving backwards through the list of
-   available register groups.  */
+/* Helper for "tui reg prev", wraps a call to REGGROUP_PREV, but adds wrap
+   around behaviour.  Returns the previous register group, or NULL if the
+   register window is not currently being displayed.  */
 
-static void
-tui_reg_prev_command (char *arg, int from_tty)
+static struct reggroup *
+tui_reg_prev (struct gdbarch *gdbarch)
 {
-  struct gdbarch *gdbarch = get_current_arch ();
+  struct reggroup *group = NULL;
 
   if (TUI_DATA_WIN != NULL)
     {
-      struct reggroup *group
-        = TUI_DATA_WIN->detail.data_display_info.current_group;
-
+      group = TUI_DATA_WIN->detail.data_display_info.current_group;
       group = reggroup_prev (gdbarch, group);
       if (group == NULL)
 	group = reggroup_prev (gdbarch, NULL);
-
-      if (group != NULL)
-	tui_show_registers (group);
     }
+  return group;
 }
 
-static void
-tui_reg_float_command (char *arg, int from_tty)
-{
-  tui_show_registers (float_reggroup);
-}
+/* Implement the 'tui reg' command.  Changes the register group displayed
+   in the tui register window.  Displays the tui register window if it is
+   not already on display.  */
 
 static void
-tui_reg_general_command (char *arg, int from_tty)
+tui_reg_command (char *args, int from_tty)
 {
-  tui_show_registers (general_reggroup);
-}
+  struct gdbarch *gdbarch = get_current_arch ();
 
-static void
-tui_reg_system_command (char *arg, int from_tty)
-{
-  tui_show_registers (system_reggroup);
+  if (args != NULL)
+    {
+      struct reggroup *group, *match = NULL;
+      size_t len = strlen (args);
+
+      /* Make sure the curses mode is enabled.  */
+      tui_enable ();
+
+      /* Make sure the register window is visible.  If not, select an
+	 appropriate layout.  We need to do this before trying to run the
+	 'next' or 'prev' commands.  */
+      if (TUI_DATA_WIN == NULL || !TUI_DATA_WIN->generic.is_visible)
+	tui_set_layout_by_name (DATA_NAME);
+
+      if (strncmp (args, "next", len) == 0)
+	match = tui_reg_next (gdbarch);
+      else if (strncmp (args, "prev", len) == 0)
+	match = tui_reg_prev (gdbarch);
+
+      /* This loop matches on the initial part of a register group
+	 name.  If this initial part in ARGS matches only one register
+	 group then the switch is made.  */
+      for (group = reggroup_next (gdbarch, NULL);
+	   group != NULL;
+	   group = reggroup_next (gdbarch, group))
+	{
+	  if (strncmp (reggroup_name (group), args, len) == 0)
+	    {
+	      if (match != NULL)
+		error (_("ambiguous register group name '%s'"), args);
+	      match = group;
+	    }
+	}
+
+      if (match == NULL)
+	error (_("unknown register group '%s'"), args);
+
+      tui_show_registers (match);
+    }
+  else
+    {
+      struct reggroup *group;
+      int first;
+
+      printf_unfiltered (_("\"tui reg\" must be followed by the name of "
+			   "either a register group,\nor one of 'next' "
+			   "or 'prev'.  Known register groups are:\n"));
+
+      for (first = 1, group = reggroup_next (gdbarch, NULL);
+	   group != NULL;
+	   first = 0, group = reggroup_next (gdbarch, group))
+	{
+	  if (!first)
+	    printf_unfiltered (", ");
+	  printf_unfiltered ("%s", reggroup_name (group));
+	}
+
+      printf_unfiltered ("\n");
+    }
 }
 
-static struct cmd_list_element *tuireglist;
+/* Complete names of register groups, and add the special "prev" and "next"
+   names.  */
 
-static void
-tui_reg_command (char *args, int from_tty)
+static VEC (char_ptr) *
+tui_reggroup_completer (struct cmd_list_element *ignore,
+			const char *text, const char *word)
 {
-  printf_unfiltered (_("\"tui reg\" must be followed by the name of a "
-                     "tui reg command.\n"));
-  help_list (tuireglist, "tui reg ", all_commands, gdb_stdout);
+  VEC (char_ptr) *result = NULL;
+  static const char *extra[] = { "next", "prev", NULL };
+  size_t len = strlen (word);
+  const char **tmp;
+
+  result = reggroup_completer (ignore, text, word);
+
+  for (tmp = extra; *tmp != NULL; ++tmp)
+    {
+      if (strncmp (word, *tmp, len) == 0)
+	VEC_safe_push (char_ptr, result, xstrdup (*tmp));
+    }
+
+  return result;
 }
 
 /* Provide a prototype to silence -Wmissing-prototypes.  */
@@ -632,30 +694,13 @@ extern initialize_file_ftype _initialize_tui_regs;
 void
 _initialize_tui_regs (void)
 {
-  struct cmd_list_element **tuicmd;
+  struct cmd_list_element **tuicmd, *cmd;
 
   tuicmd = tui_get_cmd_list ();
 
-  add_prefix_cmd ("reg", class_tui, tui_reg_command,
-                  _("TUI commands to control the register window."),
-                  &tuireglist, "tui reg ", 0,
-                  tuicmd);
-
-  add_cmd ("float", class_tui, tui_reg_float_command,
-           _("Display only floating point registers."),
-           &tuireglist);
-  add_cmd ("general", class_tui, tui_reg_general_command,
-           _("Display only general registers."),
-           &tuireglist);
-  add_cmd ("system", class_tui, tui_reg_system_command,
-           _("Display only system registers."),
-           &tuireglist);
-  add_cmd ("next", class_tui, tui_reg_next_command,
-           _("Display next register group."),
-           &tuireglist);
-  add_cmd ("prev", class_tui, tui_reg_prev_command,
-           _("Display previous register group."),
-           &tuireglist);
+  cmd = add_cmd ("reg", class_tui, tui_reg_command, _("\
+TUI command to control the register window."), tuicmd);
+  set_cmd_completer (cmd, tui_reggroup_completer);
 }