gdb: Add command completers for some info commands

Add command completion for info variables, functions, args, and
locals.  This completer only completes the command line options as
these commands all take a regexp which GDB can't really offer
completions for.

gdb/ChangeLog:

	* cli/cli-utils.c (info_print_command_completer): New function.
	* cli/cli-utils.h: Add 'completer.h' include, and forward
	declaration for 'struct cmd_list_element'.
	(info_print_command_completer): Declare.
	* stack.c (_initialize_stack): Add completer for 'info locals' and
	'info args'.
	* symtab.c (_initialize_symtab): Add completer for 'info
	variables' and 'info functions'.
	* NEWS: Mention completion for additional info commands.

6 files changed, 64 insertions, 11 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f330fb5..90af6d3 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,17 @@
 2019-07-11  Andrew Burgess  <andrew.burgess@embecosm.com>
 
+	* cli/cli-utils.c (info_print_command_completer): New function.
+	* cli/cli-utils.h: Add 'completer.h' include, and forward
+	declaration for 'struct cmd_list_element'.
+	(info_print_command_completer): Declare.
+	* stack.c (_initialize_stack): Add completer for 'info locals' and
+	'info args'.
+	* symtab.c (_initialize_symtab): Add completer for 'info
+	variables' and 'info functions'.
+	* NEWS: Mention completion for additional info commands.
+
+2019-07-11  Andrew Burgess  <andrew.burgess@embecosm.com>
+
 	* cli/cli-utils.c (extract_info_print_args): Delete.
 	(extract_arg_maybe_quoted): Delete.
 	(info_print_options_defs): New variable.
diff --git a/gdb/NEWS b/gdb/NEWS
index f7b6b88..4e479bf 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -217,7 +217,9 @@ maint show test-options-completion-result
      "taas" commands, and their "-ascending" option can now be
      abbreviated.
 
-  ** GDB can now complete the options of the "info threads" command.
+  ** GDB can now complete the options of the "info threads", "info
+     functions", "info variables", "info locals", and "info args"
+     commands.
 
   ** GDB can now complete the options of the "compile file" and
      "compile code" commands.  The "compile file" command now
diff --git a/gdb/cli/cli-utils.c b/gdb/cli/cli-utils.c
index cd3dfe6..c640550 100644
--- a/gdb/cli/cli-utils.c
+++ b/gdb/cli/cli-utils.c
@@ -473,3 +473,20 @@ extract_info_print_options (info_print_options *opts,
   if (*args != nullptr && **args == '\0')
     *args = nullptr;
 }
+
+/* See documentation in cli-utils.h.  */
+
+void
+info_print_command_completer (struct cmd_list_element *ignore,
+			      completion_tracker &tracker,
+			      const char *text, const char * /* word */)
+{
+  const auto group
+    = make_info_print_options_def_group (nullptr);
+  if (gdb::option::complete_options
+      (tracker, &text, gdb::option::PROCESS_OPTIONS_UNKNOWN_IS_OPERAND, group))
+    return;
+
+  const char *word = advance_to_expression_complete_word_point (tracker, text);
+  symbol_completer (ignore, tracker, text, word);
+}
diff --git a/gdb/cli/cli-utils.h b/gdb/cli/cli-utils.h
index a3826be..17cdd84 100644
--- a/gdb/cli/cli-utils.h
+++ b/gdb/cli/cli-utils.h
@@ -20,6 +20,10 @@
 #ifndef CLI_CLI_UTILS_H
 #define CLI_CLI_UTILS_H
 
+#include "completer.h"
+
+struct cmd_list_element;
+
 /* *PP is a string denoting a number.  Get the number.  Advance *PP
    after the string and any trailing whitespace.
 
@@ -66,6 +70,15 @@ struct info_print_options
 extern void extract_info_print_options (info_print_options *opts,
 					const char **args);
 
+/* Function that can be used as a command completer for 'info variable'
+   and friends.  This offers command option completion as well as symbol
+   completion.  At the moment all symbols are offered for all commands.  */
+
+extern void info_print_command_completer (struct cmd_list_element *ignore,
+					  completion_tracker &tracker,
+					  const char *text,
+					  const char * /* word */);
+
 /* Throws an error telling the user that ARGS starts with an option
    unrecognized by COMMAND.  */
 
diff --git a/gdb/stack.c b/gdb/stack.c
index 175f211..9b1d1a6 100644
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -3423,18 +3423,20 @@ Print information about a stack frame selected by level.\n\
 Usage: info frame level LEVEL"),
 	   &info_frame_cmd_list);
 
-  add_info ("locals", info_locals_command,
-	    info_print_args_help (_("\
+  cmd = add_info ("locals", info_locals_command,
+		  info_print_args_help (_("\
 All local variables of current stack frame or those matching REGEXPs.\n\
 Usage: info locals [-q] [-t TYPEREGEXP] [NAMEREGEXP]\n\
 Prints the local variables of the current stack frame.\n"),
 				  _("local variables")));
-  add_info ("args", info_args_command,
-	    info_print_args_help (_("\
+  set_cmd_completer_handle_brkchars (cmd, info_print_command_completer);
+  cmd = add_info ("args", info_args_command,
+		  info_print_args_help (_("\
 All argument variables of current stack frame or those matching REGEXPs.\n\
 Usage: info args [-q] [-t TYPEREGEXP] [NAMEREGEXP]\n\
 Prints the argument variables of the current stack frame.\n"),
 				  _("argument variables")));
+  set_cmd_completer_handle_brkchars (cmd, info_print_command_completer);
 
   if (dbx_commands)
     add_com ("func", class_stack, func_command, _("\
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 4669112..4189899 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -5997,28 +5997,35 @@ symbol_set_symtab (struct symbol *symbol, struct symtab *symtab)
 void
 _initialize_symtab (void)
 {
+  cmd_list_element *c;
+
   initialize_ordinary_address_classes ();
 
-  add_info ("variables", info_variables_command,
-	    info_print_args_help (_("\
+  c = add_info ("variables", info_variables_command,
+		info_print_args_help (_("\
 All global and static variable names or those matching REGEXPs.\n\
 Usage: info variables [-q] [-t TYPEREGEXP] [NAMEREGEXP]\n\
 Prints the global and static variables.\n"),
 				  _("global and static variables")));
+  set_cmd_completer_handle_brkchars (c, info_print_command_completer);
   if (dbx_commands)
-    add_com ("whereis", class_info, info_variables_command,
-	     info_print_args_help (_("\
+    {
+      c = add_com ("whereis", class_info, info_variables_command,
+		   info_print_args_help (_("\
 All global and static variable names, or those matching REGEXPs.\n\
 Usage: whereis [-q] [-t TYPEREGEXP] [NAMEREGEXP]\n\
 Prints the global and static variables.\n"),
 				   _("global and static variables")));
+      set_cmd_completer_handle_brkchars (c, info_print_command_completer);
+    }
 
-  add_info ("functions", info_functions_command,
-	    info_print_args_help (_("\
+  c = add_info ("functions", info_functions_command,
+		info_print_args_help (_("\
 All function names or those matching REGEXPs.\n\
 Usage: info functions [-q] [-t TYPEREGEXP] [NAMEREGEXP]\n\
 Prints the functions.\n"),
 				  _("functions")));
+  set_cmd_completer_handle_brkchars (c, info_print_command_completer);
 
   /* FIXME:  This command has at least the following problems:
      1.  It prints builtin types (in a very strange and confusing fashion).