gdb: rename cfunc to simple_func

After browsing the CLI code for quite a while and trying really hard, I
reached the conclusion that I can't give a meaningful explanation of
what "sfunc" and "cfunc" functions are, in cmd_list_element.  I don't
see a logic at all.  That makes it very difficult to do any kind of
change.  Unless somebody can make sense out of all that, I'd like to try
to retro-fit some logic in the cmd_list_element callback function code
so that we can understand what is going on, do some cleanups and add new
features.

The first change is about "cfunc".  I can't figure out what the "c" in
cfunc means.  It's not const, because there's already "const" in
"cmd_const_cfunc_ftype", and the previous "cmd_cfunc_ftype" had nothing
const..  It's not "cmd" or "command", because there's already "cmd" in
"cmd_const_cfunc_ftype".

The "main" command callback, cmd_list_element::func, has three
parameters, whereas cfunc has two.  It is missing the cmd_list_element
parameter.  So the only reason I see for cfunc to exist is to be a shim
between the three and two parameter versions.  Most commands don't need
to receive the cmd_list_element object, so adding it everywhere would be
long and would just add more unnecessary boilerplate.  So since this is
the "simple" version of the callback, compared to the "full", I suggest
renaming cmd_const_cfunc_ftype into cmd_simple_func_ftype, as well as
everything (like the utility functions) that goes with it.

Change-Id: I4e46cacfd77a66bc1cbf683f6a362072504b7868

5 files changed, 53 insertions, 44 deletions

diff --git a/gdb/cli/cli-cmds.c b/gdb/cli/cli-cmds.c
index 56ae12a..5ff0b77 100644
--- a/gdb/cli/cli-cmds.c
+++ b/gdb/cli/cli-cmds.c
@@ -443,7 +443,7 @@ complete_command (const char *arg, int from_tty)
 int
 is_complete_command (struct cmd_list_element *c)
 {
-  return cmd_cfunc_eq (c, complete_command);
+  return cmd_simple_func_eq (c, complete_command);
 }
 
 static void
diff --git a/gdb/cli/cli-decode.c b/gdb/cli/cli-decode.c
index 633a3ad..3c39e47 100644
--- a/gdb/cli/cli-decode.c
+++ b/gdb/cli/cli-decode.c
@@ -94,22 +94,23 @@ print_help_for_command (struct cmd_list_element *c,
 
 /* Set the callback function for the specified command.  For each both
    the commands callback and func() are set.  The latter set to a
-   bounce function (unless cfunc / sfunc is NULL that is).  */
+   bounce function (unless simple_func / sfunc is NULL that is).  */
 
 static void
-do_const_cfunc (struct cmd_list_element *c, const char *args, int from_tty)
+do_simple_func (struct cmd_list_element *c, const char *args, int from_tty)
 {
-  c->function.const_cfunc (args, from_tty);
+  c->function.simple_func (args, from_tty);
 }
 
 static void
-set_cmd_cfunc (struct cmd_list_element *cmd, cmd_const_cfunc_ftype *cfunc)
+set_cmd_simple_func (struct cmd_list_element *cmd, cmd_simple_func_ftype *simple_func)
 {
-  if (cfunc == NULL)
+  if (simple_func == NULL)
     cmd->func = NULL;
   else
-    cmd->func = do_const_cfunc;
-  cmd->function.const_cfunc = cfunc;
+    cmd->func = do_simple_func;
+
+  cmd->function.simple_func = simple_func;
 }
 
 static void
@@ -129,9 +130,10 @@ set_cmd_sfunc (struct cmd_list_element *cmd, cmd_const_sfunc_ftype *sfunc)
 }
 
 int
-cmd_cfunc_eq (struct cmd_list_element *cmd, cmd_const_cfunc_ftype *cfunc)
+cmd_simple_func_eq (struct cmd_list_element *cmd, cmd_simple_func_ftype *simple_func)
 {
-  return cmd->func == do_const_cfunc && cmd->function.const_cfunc == cfunc;
+  return (cmd->func == do_simple_func
+	  && cmd->function.simple_func == simple_func);
 }
 
 void
@@ -238,17 +240,17 @@ add_cmd (const char *name, enum command_class theclass,
 {
   cmd_list_element *result = do_add_cmd (name, theclass, doc, list);
   result->func = NULL;
-  result->function.const_cfunc = NULL;
+  result->function.simple_func = NULL;
   return result;
 }
 
 struct cmd_list_element *
 add_cmd (const char *name, enum command_class theclass,
-	 cmd_const_cfunc_ftype *fun,
+	 cmd_simple_func_ftype *fun,
 	 const char *doc, struct cmd_list_element **list)
 {
   cmd_list_element *result = do_add_cmd (name, theclass, doc, list);
-  set_cmd_cfunc (result, fun);
+  set_cmd_simple_func (result, fun);
   return result;
 }
 
@@ -256,7 +258,7 @@ add_cmd (const char *name, enum command_class theclass,
 
 struct cmd_list_element *
 add_cmd_suppress_notification (const char *name, enum command_class theclass,
-			       cmd_const_cfunc_ftype *fun, const char *doc,
+			       cmd_simple_func_ftype *fun, const char *doc,
 			       struct cmd_list_element **list,
 			       int *suppress_notification)
 {
@@ -359,7 +361,7 @@ update_prefix_field_of_prefixed_commands (struct cmd_list_element *c)
 
 struct cmd_list_element *
 add_prefix_cmd (const char *name, enum command_class theclass,
-		cmd_const_cfunc_ftype *fun,
+		cmd_simple_func_ftype *fun,
 		const char *doc, struct cmd_list_element **subcommands,
 		int allow_unknown, struct cmd_list_element **list)
 {
@@ -432,7 +434,7 @@ add_show_prefix_cmd (const char *name, enum command_class theclass,
 struct cmd_list_element *
 add_prefix_cmd_suppress_notification
 	       (const char *name, enum command_class theclass,
-		cmd_const_cfunc_ftype *fun,
+		cmd_simple_func_ftype *fun,
 		const char *doc, struct cmd_list_element **subcommands,
 		int allow_unknown, struct cmd_list_element **list,
 		int *suppress_notification)
@@ -448,7 +450,7 @@ add_prefix_cmd_suppress_notification
 
 struct cmd_list_element *
 add_abbrev_prefix_cmd (const char *name, enum command_class theclass,
-		       cmd_const_cfunc_ftype *fun, const char *doc,
+		       cmd_simple_func_ftype *fun, const char *doc,
 		       struct cmd_list_element **subcommands,
 		       int allow_unknown, struct cmd_list_element **list)
 {
@@ -460,7 +462,7 @@ add_abbrev_prefix_cmd (const char *name, enum command_class theclass,
   return c;
 }
 
-/* This is an empty "cfunc".  */
+/* This is an empty "simple func".  */
 void
 not_just_help_class_command (const char *args, int from_tty)
 {
@@ -951,7 +953,7 @@ delete_cmd (const char *name, struct cmd_list_element **list,
 /* Add an element to the list of info subcommands.  */
 
 struct cmd_list_element *
-add_info (const char *name, cmd_const_cfunc_ftype *fun, const char *doc)
+add_info (const char *name, cmd_simple_func_ftype *fun, const char *doc)
 {
   return add_cmd (name, class_info, fun, doc, &infolist);
 }
@@ -968,7 +970,7 @@ add_info_alias (const char *name, cmd_list_element *target, int abbrev_flag)
 
 struct cmd_list_element *
 add_com (const char *name, enum command_class theclass,
-	 cmd_const_cfunc_ftype *fun,
+	 cmd_simple_func_ftype *fun,
 	 const char *doc)
 {
   return add_cmd (name, theclass, fun, doc, &cmdlist);
@@ -990,7 +992,7 @@ add_com_alias (const char *name, cmd_list_element *target,
 
 struct cmd_list_element *
 add_com_suppress_notification (const char *name, enum command_class theclass,
-			       cmd_const_cfunc_ftype *fun, const char *doc,
+			       cmd_simple_func_ftype *fun, const char *doc,
 			       int *suppress_notification)
 {
   return add_cmd_suppress_notification (name, theclass, fun, doc,
@@ -2167,5 +2169,5 @@ int
 cli_user_command_p (struct cmd_list_element *cmd)
 {
   return (cmd->theclass == class_user
-	  && (cmd->func == do_const_cfunc || cmd->func == do_sfunc));
+	  && (cmd->func == do_simple_func || cmd->func == do_sfunc));
 }
diff --git a/gdb/cli/cli-decode.h b/gdb/cli/cli-decode.h
index 241535a..4cbdf7f 100644
--- a/gdb/cli/cli-decode.h
+++ b/gdb/cli/cli-decode.h
@@ -174,8 +174,12 @@ struct cmd_list_element
      to one of the below.  */
   union
     {
-      /* If type is not_set_cmd, call it like this: */
-      cmd_const_cfunc_ftype *const_cfunc;
+      /* Most commands don't need the cmd_list_element parameter passed to FUNC.
+	 They therefore register a command of this type, which doesn't have the
+	 cmd_list_element parameter.  do_simple_func is installed as FUNC, and
+	 acts as a shim between the two.  */
+      cmd_simple_func_ftype *simple_func;
+
       /* If type is set_cmd or show_cmd, first set the variables,
 	 and then call this: */
       cmd_const_sfunc_ftype *sfunc;
diff --git a/gdb/command.h b/gdb/command.h
index 711cbdc..1bda67c 100644
--- a/gdb/command.h
+++ b/gdb/command.h
@@ -128,7 +128,10 @@ var_types;
 /* This structure records one command'd definition.  */
 struct cmd_list_element;
 
-typedef void cmd_const_cfunc_ftype (const char *args, int from_tty);
+/* The "simple" signature of command callbacks, which doesn't include a
+   cmd_list_element parameter.  */
+
+typedef void cmd_simple_func_ftype (const char *args, int from_tty);
 
 /* This structure specifies notifications to be suppressed by a cli
    command interpreter.  */
@@ -158,7 +161,7 @@ extern bool valid_cmd_char_p (int c);
 /* Const-correct variant of the above.  */
 
 extern struct cmd_list_element *add_cmd (const char *, enum command_class,
-					 cmd_const_cfunc_ftype *fun,
+					 cmd_simple_func_ftype *fun,
 					 const char *,
 					 struct cmd_list_element **);
 
@@ -170,7 +173,7 @@ extern struct cmd_list_element *add_cmd (const char *, enum command_class,
 
 extern struct cmd_list_element *add_cmd_suppress_notification
 			(const char *name, enum command_class theclass,
-			 cmd_const_cfunc_ftype *fun, const char *doc,
+			 cmd_simple_func_ftype *fun, const char *doc,
 			 struct cmd_list_element **list,
 			 int *suppress_notification);
 
@@ -181,7 +184,7 @@ extern struct cmd_list_element *add_alias_cmd (const char *,
 
 
 extern struct cmd_list_element *add_prefix_cmd (const char *, enum command_class,
-						cmd_const_cfunc_ftype *fun,
+						cmd_simple_func_ftype *fun,
 						const char *,
 						struct cmd_list_element **,
 						int,
@@ -203,7 +206,7 @@ extern struct cmd_list_element *add_show_prefix_cmd
 
 extern struct cmd_list_element *add_prefix_cmd_suppress_notification
 			(const char *name, enum command_class theclass,
-			 cmd_const_cfunc_ftype *fun,
+			 cmd_simple_func_ftype *fun,
 			 const char *doc, struct cmd_list_element **subcommands,
 			 int allow_unknown,
 			 struct cmd_list_element **list,
@@ -211,7 +214,7 @@ extern struct cmd_list_element *add_prefix_cmd_suppress_notification
 
 extern struct cmd_list_element *add_abbrev_prefix_cmd (const char *,
 						       enum command_class,
-						       cmd_const_cfunc_ftype *fun,
+						       cmd_simple_func_ftype *fun,
 						       const char *,
 						       struct cmd_list_element
 						       **, int,
@@ -250,8 +253,8 @@ extern void set_cmd_completer_handle_brkchars (struct cmd_list_element *,
 
 /* HACK: cagney/2002-02-23: Code, mostly in tracepoints.c, grubs
    around in cmd objects to test the value of the commands sfunc().  */
-extern int cmd_cfunc_eq (struct cmd_list_element *cmd,
-			 cmd_const_cfunc_ftype *cfun);
+extern int cmd_simple_func_eq (struct cmd_list_element *cmd,
+			 cmd_simple_func_ftype *cfun);
 
 /* Execute CMD's pre/post hook.  Throw an error if the command fails.
    If already executing this pre/post hook, or there is no pre/post
@@ -346,7 +349,7 @@ extern int lookup_cmd_composition (const char *text,
 				   struct cmd_list_element **cmd);
 
 extern struct cmd_list_element *add_com (const char *, enum command_class,
-					 cmd_const_cfunc_ftype *fun,
+					 cmd_simple_func_ftype *fun,
 					 const char *);
 
 extern cmd_list_element *add_com_alias (const char *name,
@@ -356,11 +359,11 @@ extern cmd_list_element *add_com_alias (const char *name,
 
 extern struct cmd_list_element *add_com_suppress_notification
 		       (const char *name, enum command_class theclass,
-			cmd_const_cfunc_ftype *fun, const char *doc,
+			cmd_simple_func_ftype *fun, const char *doc,
 			int *supress_notification);
 
 extern struct cmd_list_element *add_info (const char *,
-					  cmd_const_cfunc_ftype *fun,
+					  cmd_simple_func_ftype *fun,
 					  const char *);
 
 extern cmd_list_element *add_info_alias (const char *name,
diff --git a/gdb/tracepoint.c b/gdb/tracepoint.c
index 83a32ec..06cf9ca 100644
--- a/gdb/tracepoint.c
+++ b/gdb/tracepoint.c
@@ -655,7 +655,7 @@ validate_actionline (const char *line, struct breakpoint *b)
   if (c == 0)
     error (_("`%s' is not a tracepoint action, or is ambiguous."), p);
 
-  if (cmd_cfunc_eq (c, collect_pseudocommand))
+  if (cmd_simple_func_eq (c, collect_pseudocommand))
     {
       int trace_string = 0;
 
@@ -723,7 +723,7 @@ validate_actionline (const char *line, struct breakpoint *b)
       while (p && *p++ == ',');
     }
 
-  else if (cmd_cfunc_eq (c, teval_pseudocommand))
+  else if (cmd_simple_func_eq (c, teval_pseudocommand))
     {
       do
 	{			/* Repeat over a comma-separated list.  */
@@ -750,7 +750,7 @@ validate_actionline (const char *line, struct breakpoint *b)
       while (p && *p++ == ',');
     }
 
-  else if (cmd_cfunc_eq (c, while_stepping_pseudocommand))
+  else if (cmd_simple_func_eq (c, while_stepping_pseudocommand))
     {
       char *endp;
 
@@ -761,7 +761,7 @@ validate_actionline (const char *line, struct breakpoint *b)
       p = endp;
     }
 
-  else if (cmd_cfunc_eq (c, end_actions_pseudocommand))
+  else if (cmd_simple_func_eq (c, end_actions_pseudocommand))
     ;
 
   else
@@ -1308,7 +1308,7 @@ encode_actions_1 (struct command_line *action,
       if (cmd == 0)
 	error (_("Bad action list item: %s"), action_exp);
 
-      if (cmd_cfunc_eq (cmd, collect_pseudocommand))
+      if (cmd_simple_func_eq (cmd, collect_pseudocommand))
 	{
 	  int trace_string = 0;
 
@@ -1464,7 +1464,7 @@ encode_actions_1 (struct command_line *action,
 	    }
 	  while (action_exp && *action_exp++ == ',');
 	}			/* if */
-      else if (cmd_cfunc_eq (cmd, teval_pseudocommand))
+      else if (cmd_simple_func_eq (cmd, teval_pseudocommand))
 	{
 	  do
 	    {			/* Repeat over a comma-separated list.  */
@@ -1488,7 +1488,7 @@ encode_actions_1 (struct command_line *action,
 	    }
 	  while (action_exp && *action_exp++ == ',');
 	}			/* if */
-      else if (cmd_cfunc_eq (cmd, while_stepping_pseudocommand))
+      else if (cmd_simple_func_eq (cmd, while_stepping_pseudocommand))
 	{
 	  /* We check against nested while-stepping when setting
 	     breakpoint action, so no way to run into nested
@@ -2690,13 +2690,13 @@ trace_dump_actions (struct command_line *action,
       if (cmd == 0)
 	error (_("Bad action list item: %s"), action_exp);
 
-      if (cmd_cfunc_eq (cmd, while_stepping_pseudocommand))
+      if (cmd_simple_func_eq (cmd, while_stepping_pseudocommand))
 	{
 	  gdb_assert (action->body_list_1 == nullptr);
 	  trace_dump_actions (action->body_list_0.get (),
 			      1, stepping_frame, from_tty);
 	}
-      else if (cmd_cfunc_eq (cmd, collect_pseudocommand))
+      else if (cmd_simple_func_eq (cmd, collect_pseudocommand))
 	{
 	  /* Display the collected data.
 	     For the trap frame, display only what was collected at