gdb: include help aliases in help command completion

There are a bunch of aliases that get used with help, but the current
command completion logic does not include those when doing completions.

Since the framework is already mostly in place, extend complete_on_cmdlist
slightly to pass down the ignore_help_classes flag like is done with the
existing lookup command logic.

Now you can do:
	(gdb) help use<tab>
and get back:
	(gdb) help user-defined

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

gdb/ChangeLog

@@ -1,3 +1,12 @@
+2012-11-20  Mike Frysinger  <vapier@gentoo.org>
+
+	* cli/cli-decode.c (complete_on_cmdlist): Add a fourth arg and check
+	it when looking at ptr->func.
+	* command.h (complete_on_cmdlist): Add a fourth arg.
+	* completer.c (complete_line_internal): Add local ignore_help_classes,
+	and set it to 1 when reason is not handle_help.  Pass this down to
+	lookup_cmd_1 and complete_on_cmdlist.
+
 2012-11-20  Tom Tromey  <tromey@redhat.com>
 
 	* completer.c (count_struct_fields): Remove.

gdb/cli/cli-decode.c

@@ -1726,7 +1726,8 @@ lookup_cmd_composition (char *text,
    "oobar"; if WORD is "baz/foo", return "baz/foobar".  */
 
 VEC (char_ptr) *
-complete_on_cmdlist (struct cmd_list_element *list, char *text, char *word)
+complete_on_cmdlist (struct cmd_list_element *list, char *text, char *word,
+		     int ignore_help_classes)
 {
   struct cmd_list_element *ptr;
   VEC (char_ptr) *matchlist = NULL;
@@ -1743,7 +1744,7 @@ complete_on_cmdlist (struct cmd_list_element *list, char *text, char *word)
       for (ptr = list; ptr; ptr = ptr->next)
 	if (!strncmp (ptr->name, text, textlen)
 	    && !ptr->abbrev_flag
-	    && (ptr->func
+	    && (!ignore_help_classes || ptr->func
 		|| ptr->prefixlist))
 	  {
 	    char *match;

gdb/command.h

@@ -216,7 +216,7 @@ extern struct cmd_list_element *add_info (char *,
 extern struct cmd_list_element *add_info_alias (char *, char *, int);
 
 extern VEC (char_ptr) *complete_on_cmdlist (struct cmd_list_element *,
-					    char *, char *);
+					    char *, char *, int);
 
 extern VEC (char_ptr) *complete_on_enum (const char *const *enumlist,
 					 char *, char *);

gdb/completer.c

@@ -501,6 +501,7 @@ complete_line_internal (const char *text,
 {
   VEC (char_ptr) *list = NULL;
   char *tmp_command, *p;
+  int ignore_help_classes;
   /* Pointer within tmp_command which corresponds to text.  */
   char *word;
   struct cmd_list_element *c, *result_list;
@@ -520,6 +521,9 @@ complete_line_internal (const char *text,
   tmp_command = (char *) alloca (point + 1);
   p = tmp_command;
 
+  /* The help command should complete help aliases.  */
+  ignore_help_classes = reason != handle_help;
+
   strncpy (tmp_command, line_buffer, point);
   tmp_command[point] = '\0';
   /* Since text always contains some number of characters leading up
@@ -536,7 +540,7 @@ complete_line_internal (const char *text,
     }
   else
     {
-      c = lookup_cmd_1 (&p, cmdlist, &result_list, 1);
+      c = lookup_cmd_1 (&p, cmdlist, &result_list, ignore_help_classes);
     }
 
   /* Move p up to the next interesting thing.  */
@@ -577,12 +581,13 @@ complete_line_internal (const char *text,
 	    {
 	      if (reason != handle_brkchars)
 		list = complete_on_cmdlist (*result_list->prefixlist, p,
-					    word);
+					    word, ignore_help_classes);
 	    }
 	  else
 	    {
 	      if (reason != handle_brkchars)
-		list = complete_on_cmdlist (cmdlist, p, word);
+		list = complete_on_cmdlist (cmdlist, p, word,
+					    ignore_help_classes);
 	    }
 	  /* Ensure that readline does the right thing with respect to
 	     inserting quotes.  */
@@ -608,7 +613,8 @@ complete_line_internal (const char *text,
 		  /* It is a prefix command; what comes after it is
 		     a subcommand (e.g. "info ").  */
 		  if (reason != handle_brkchars)
-		    list = complete_on_cmdlist (*c->prefixlist, p, word);
+		    list = complete_on_cmdlist (*c->prefixlist, p, word,
+						ignore_help_classes);
 
 		  /* Ensure that readline does the right thing
 		     with respect to inserting quotes.  */
@@ -679,7 +685,8 @@ complete_line_internal (const char *text,
 		}
 
 	      if (reason != handle_brkchars)
-		list = complete_on_cmdlist (result_list, q, word);
+		list = complete_on_cmdlist (result_list, q, word,
+					    ignore_help_classes);
 
 	      /* Ensure that readline does the right thing
 		 with respect to inserting quotes.  */

gdb/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2012-11-20  Mike Frysinger  <vapier@gentoo.org>
+
+	* gdb.base/completion.exp: Add test for help aliases completion.
+
 2012-11-20  Yao Qi  <yao@codesourcery.com>
 
 	* gdb.mi/mi-cmd-param-changed.exp (test_command_param_changed):

gdb/testsuite/gdb.base/completion.exp

@@ -389,6 +389,19 @@ gdb_test_multiple "" "$test" {
     }
 }
 
+set test "complete help aliases"
+send_gdb "help user-define\t"
+gdb_test_multiple "" "$test" {
+    -re "^help user-defined $" {
+	send_gdb "\n"
+	gdb_test_multiple "" "$test" {
+	    -re "$gdb_prompt $" {
+		pass "$test"
+	    }
+	}
+    }
+}
+
 
 # These tests used to try completing the shorter "p b-a".
 # Unfortunately, on some systems, there are .o files in system