Add alias command to cmd_list_element

When we add alias command, we call add_alias_cmd and pass the alias name
and command name.  This implicitly requires the command and its prefix
commands are already added to cmdlist.  This may not be true, for example,

  add_com_alias ("tty", "set inferior-tty", class_alias, 0);

"inferior-tty" command is added to setlist, but setlist may not be added
to cmdlist (It depends on the order of related _initialize_XXX functions
called) so that we can't find "set inferior-tty" from cmdlist.

This patch fixes this problem by passing cmd_list_element of "inferior-tty"
to add_alias_cmd, so that cmd_list_element of "inferior-tty" doesn't have
to be reachable from cmdlist at that moment.

gdb:

2017-05-17  Yao Qi  <yao.qi@linaro.org>

	* cli/cli-decode.c (add_alias_cmd): New function.
	* command.h (add_alias_cmd): Declare.
	* infcmd.c (_initialize_infcmd): Don't call add_com_alias,
	instead call add_alias_cmd.

gdb/testsuite:

2017-05-17  Simon Marchi  <simon.marchi@ericsson.com>

	* gdb.base/set-inferior-tty.exp (test_set_inferior_tty): Add
	argument command.
	(top-level): Invoke test_set_inferior_tty.

1 files changed, 19 insertions, 10 deletions

diff --git a/gdb/cli/cli-decode.c b/gdb/cli/cli-decode.c
index d45733e..d386d02 100644
--- a/gdb/cli/cli-decode.c
+++ b/gdb/cli/cli-decode.c
@@ -284,16 +284,10 @@ deprecate_cmd (struct cmd_list_element *cmd, const char *replacement)
 }
 
 struct cmd_list_element *
-add_alias_cmd (const char *name, const char *oldname, enum command_class theclass,
-	       int abbrev_flag, struct cmd_list_element **list)
+add_alias_cmd (const char *name, cmd_list_element *old,
+	       enum command_class theclass, int abbrev_flag,
+	       struct cmd_list_element **list)
 {
-  const char *tmp;
-  struct cmd_list_element *old;
-  struct cmd_list_element *c;
-
-  tmp = oldname;
-  old = lookup_cmd (&tmp, *list, "", 1, 1);
-
   if (old == 0)
     {
       struct cmd_list_element *prehook, *prehookee, *posthook, *posthookee;
@@ -307,7 +301,7 @@ add_alias_cmd (const char *name, const char *oldname, enum command_class theclas
       return 0;
     }
 
-  c = add_cmd (name, theclass, NULL, old->doc, list);
+  struct cmd_list_element *c = add_cmd (name, theclass, NULL, old->doc, list);
 
   /* If OLD->DOC can be freed, we should make another copy.  */
   if (old->doc_allocated)
@@ -330,6 +324,21 @@ add_alias_cmd (const char *name, const char *oldname, enum command_class theclas
   return c;
 }
 
+struct cmd_list_element *
+add_alias_cmd (const char *name, const char *oldname,
+	       enum command_class theclass, int abbrev_flag,
+	       struct cmd_list_element **list)
+{
+  const char *tmp;
+  struct cmd_list_element *old;
+
+  tmp = oldname;
+  old = lookup_cmd (&tmp, *list, "", 1, 1);
+
+  return add_alias_cmd (name, old, theclass, abbrev_flag, list);
+}
+
+
 /* Like add_cmd but adds an element for a command prefix: a name that
    should be followed by a subcommand to be looked up in another
    command list.  PREFIXLIST should be the address of the variable