Allocate cmd_list_element with new

This adds a constructor and destructor to cmd_list_element and changes
it to be allocated with new.  This will be useful in a subsequent
patch.

ChangeLog
2018-05-04  Tom Tromey  <tom@tromey.com>

	* cli/cli-decode.h (cmd_list_element): New constructor.
	(~cmd_list_element): New destructor.
	(struct cmd_list_element): Add initializers.
	* cli/cli-decode.c (do_add_cmd): Use "new".
	(delete_cmd): Use "delete".

3 files changed, 62 insertions, 55 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 16b3a7e..93afc6f 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,11 @@
+2018-05-04  Tom Tromey  <tom@tromey.com>
+
+	* cli/cli-decode.h (cmd_list_element): New constructor.
+	(~cmd_list_element): New destructor.
+	(struct cmd_list_element): Add initializers.
+	* cli/cli-decode.c (do_add_cmd): Use "new".
+	(delete_cmd): Use "delete".
+
 2018-05-04  Jan Kratochvil  <jan.kratochvil@redhat.com>
 	    Pedro Alves <palves@redhat.com>
 
diff --git a/gdb/cli/cli-decode.c b/gdb/cli/cli-decode.c
index 0afe36a..c8dda70 100644
--- a/gdb/cli/cli-decode.c
+++ b/gdb/cli/cli-decode.c
@@ -193,7 +193,8 @@ static struct cmd_list_element *
 do_add_cmd (const char *name, enum command_class theclass,
 	    const char *doc, struct cmd_list_element **list)
 {
-  struct cmd_list_element *c = XNEW (struct cmd_list_element);
+  struct cmd_list_element *c = new struct cmd_list_element (name, theclass,
+							    doc);
   struct cmd_list_element *p, *iter;
 
   /* Turn each alias of the old command into an alias of the new
@@ -227,34 +228,6 @@ do_add_cmd (const char *name, enum command_class theclass,
       p->next = c;
     }
 
-  c->name = name;
-  c->theclass = theclass;
-  set_cmd_context (c, NULL);
-  c->doc = doc;
-  c->cmd_deprecated = 0;
-  c->deprecated_warn_user = 0;
-  c->malloced_replacement = 0;
-  c->doc_allocated = 0;
-  c->replacement = NULL;
-  c->pre_show_hook = NULL;
-  c->hook_in = 0;
-  c->prefixlist = NULL;
-  c->prefixname = NULL;
-  c->allow_unknown = 0;
-  c->prefix = NULL;
-  c->abbrev_flag = 0;
-  set_cmd_completer (c, symbol_completer);
-  c->completer_handle_brkchars = NULL;
-  c->destroyer = NULL;
-  c->type = not_set_cmd;
-  c->var = NULL;
-  c->var_type = var_boolean;
-  c->enums = NULL;
-  c->user_commands = NULL;
-  c->cmd_pointer = NULL;
-  c->alias_chain = NULL;
-  c->suppress_notification = NULL;
-
   return c;
 }
 
@@ -841,8 +814,6 @@ delete_cmd (const char *name, struct cmd_list_element **list,
 	  *prehookee = iter->hookee_pre;
 	  if (iter->hookee_post)
 	    iter->hookee_post->hook_post = 0;
-	  if (iter->doc && iter->doc_allocated)
-	    xfree ((char *) iter->doc);
 	  *posthook = iter->hook_post;
 	  *posthookee = iter->hookee_post;
 
@@ -866,7 +837,7 @@ delete_cmd (const char *name, struct cmd_list_element **list,
 	      *prevp = iter->alias_chain;
 	    }
 
-	  xfree (iter);
+	  delete iter;
 
 	  /* We won't see another command with the same name.  */
 	  break;
diff --git a/gdb/cli/cli-decode.h b/gdb/cli/cli-decode.h
index 30b4fa7..a3208e1 100644
--- a/gdb/cli/cli-decode.h
+++ b/gdb/cli/cli-decode.h
@@ -45,8 +45,35 @@ cmd_types;
 
 struct cmd_list_element
   {
+    cmd_list_element (const char *name_, enum command_class theclass_,
+		      const char *doc_)
+      : name (name_),
+	theclass (theclass_),
+	cmd_deprecated (0),
+	deprecated_warn_user (0),
+	malloced_replacement (0),
+	doc_allocated (0),
+	hook_in (0),
+	allow_unknown (0),
+	abbrev_flag (0),
+	type (not_set_cmd),
+	var_type (var_boolean),
+	doc (doc_)
+    {
+      memset (&function, 0, sizeof (function));
+    }
+
+    ~cmd_list_element ()
+    {
+      if (doc && doc_allocated)
+	xfree ((char *) doc);
+    }
+
+    DISABLE_COPY_AND_ASSIGN (cmd_list_element);
+
+
     /* Points to next command in this list.  */
-    struct cmd_list_element *next;
+    struct cmd_list_element *next = nullptr;
 
     /* Name of this command.  */
     const char *name;
@@ -107,7 +134,8 @@ struct cmd_list_element
        cagney/2002-02-02: This function signature is evolving.  For
        the moment suggest sticking with either set_cmd_cfunc() or
        set_cmd_sfunc().  */
-    void (*func) (struct cmd_list_element *c, const char *args, int from_tty);
+    void (*func) (struct cmd_list_element *c, const char *args, int from_tty)
+      = nullptr;
     /* The command's real callback.  At present func() bounces through
        to one of the below.  */
     union
@@ -121,7 +149,7 @@ struct cmd_list_element
     function;
 
     /* Local state (context) for this command.  This can be anything.  */
-    void *context;
+    void *context = nullptr;
 
     /* Documentation of this command (or help topic).
        First line is brief documentation; remaining lines form, with it,
@@ -131,37 +159,37 @@ struct cmd_list_element
 
     /* For set/show commands.  A method for printing the output to the
        specified stream.  */
-    show_value_ftype *show_value_func;
+    show_value_ftype *show_value_func = nullptr;
 
     /* If this command is deprecated, this is the replacement name.  */
-    const char *replacement;
+    const char *replacement = nullptr;
 
     /* If this command represents a show command, then this function
        is called before the variable's value is examined.  */
-    void (*pre_show_hook) (struct cmd_list_element *c);
+    void (*pre_show_hook) (struct cmd_list_element *c) = nullptr;
 
     /* Hook for another command to be executed before this command.  */
-    struct cmd_list_element *hook_pre;
+    struct cmd_list_element *hook_pre = nullptr;
 
     /* Hook for another command to be executed after this command.  */
-    struct cmd_list_element *hook_post;
+    struct cmd_list_element *hook_post = nullptr;
 
     /* Nonzero identifies a prefix command.  For them, the address
        of the variable containing the list of subcommands.  */
-    struct cmd_list_element **prefixlist;
+    struct cmd_list_element **prefixlist = nullptr;
 
     /* For prefix commands only:
        String containing prefix commands to get here: this one
        plus any others needed to get to it.  Should end in a space.
        It is used before the word "command" in describing the
        commands reached through this prefix.  */
-    const char *prefixname;
+    const char *prefixname = nullptr;
 
     /* The prefix command of this command.  */
-    struct cmd_list_element *prefix;
+    struct cmd_list_element *prefix = nullptr;
 
     /* Completion routine for this command.  */
-    completer_ftype *completer;
+    completer_ftype *completer = symbol_completer;
 
     /* Handle the word break characters for this completer.  Usually
        this function need not be defined, but for some types of
@@ -169,47 +197,47 @@ struct cmd_list_element
        a class) the word break chars may need to be redefined
        depending on the completer type (e.g., for filename
        completers).  */
-    completer_handle_brkchars_ftype *completer_handle_brkchars;
+    completer_handle_brkchars_ftype *completer_handle_brkchars = nullptr;
 
     /* Destruction routine for this command.  If non-NULL, this is
        called when this command instance is destroyed.  This may be
        used to finalize the CONTEXT field, if needed.  */
-    void (*destroyer) (struct cmd_list_element *self, void *context);
+    void (*destroyer) (struct cmd_list_element *self, void *context) = nullptr;
 
     /* Pointer to variable affected by "set" and "show".  Doesn't
        matter if type is not_set.  */
-    void *var;
+    void *var = nullptr;
 
     /* Pointer to NULL terminated list of enumerated values (like
        argv).  */
-    const char *const *enums;
+    const char *const *enums = nullptr;
 
     /* Pointer to command strings of user-defined commands */
-    struct command_line *user_commands;
+    struct command_line *user_commands = nullptr;
 
     /* Pointer to command that is hooked by this one, (by hook_pre)
        so the hook can be removed when this one is deleted.  */
-    struct cmd_list_element *hookee_pre;
+    struct cmd_list_element *hookee_pre = nullptr;
 
     /* Pointer to command that is hooked by this one, (by hook_post)
        so the hook can be removed when this one is deleted.  */
-    struct cmd_list_element *hookee_post;
+    struct cmd_list_element *hookee_post = nullptr;
 
     /* Pointer to command that is aliased by this one, so the
        aliased command can be located in case it has been hooked.  */
-    struct cmd_list_element *cmd_pointer;
+    struct cmd_list_element *cmd_pointer = nullptr;
 
     /* Start of a linked list of all aliases of this command.  */
-    struct cmd_list_element *aliases;
+    struct cmd_list_element *aliases = nullptr;
 
     /* Link pointer for aliases on an alias list.  */
-    struct cmd_list_element *alias_chain;
+    struct cmd_list_element *alias_chain = nullptr;
 
     /* If non-null, the pointer to a field in 'struct
        cli_suppress_notification', which will be set to true in cmd_func
        when this command is being executed.  It will be set back to false
        when the command has been executed.  */
-    int *suppress_notification;
+    int *suppress_notification = nullptr;
   };
 
 extern void help_cmd_list (struct cmd_list_element *, enum command_class,