gdb: make add_com_alias accept target as a cmd_list_element

The alias creation functions currently accept a name to specify the
target command.  They pass this to add_alias_cmd, which needs to lookup
the target command by name.

Given that:

 - We don't support creating an alias for a command before that command
   exists.
 - We always use add_info_alias just after creating that target command,
   and therefore have access to the target command's cmd_list_element.

... change add_com_alias to accept the target command as a
cmd_list_element (other functions are done in subsequent patches).  This
ensures we don't create the alias before the target command, because you
need to get the cmd_list_element from somewhere when you call the alias
creation function.  And it avoids an unecessary command lookup.  So it
seems better to me in every aspect.

gdb/ChangeLog:

	* command.h (add_com_alias): Accept target as
	cmd_list_element.  Update callers.

Change-Id: I24bed7da57221cc77606034de3023fedac015150

1 files changed, 19 insertions, 18 deletions

diff --git a/gdb/reverse.c b/gdb/reverse.c
index e51defb..feca1b6 100644
--- a/gdb/reverse.c
+++ b/gdb/reverse.c
@@ -326,38 +326,39 @@ void _initialize_reverse ();
 void
 _initialize_reverse ()
 {
-  add_com ("reverse-step", class_run, reverse_step, _("\
+  cmd_list_element *reverse_step_cmd
+   = add_com ("reverse-step", class_run, reverse_step, _("\
 Step program backward until it reaches the beginning of another source line.\n\
-Argument N means do this N times (or till program stops for another reason).")
-	   );
-  add_com_alias ("rs", "reverse-step", class_run, 1);
+Argument N means do this N times (or till program stops for another reason)."));
+  add_com_alias ("rs", reverse_step_cmd, class_run, 1);
 
-  add_com ("reverse-next", class_run, reverse_next, _("\
+  cmd_list_element *reverse_next_cmd
+    = add_com ("reverse-next", class_run, reverse_next, _("\
 Step program backward, proceeding through subroutine calls.\n\
 Like the \"reverse-step\" command as long as subroutine calls do not happen;\n\
 when they do, the call is treated as one instruction.\n\
-Argument N means do this N times (or till program stops for another reason).")
-	   );
-  add_com_alias ("rn", "reverse-next", class_run, 1);
+Argument N means do this N times (or till program stops for another reason)."));
+  add_com_alias ("rn", reverse_next_cmd, class_run, 1);
 
-  add_com ("reverse-stepi", class_run, reverse_stepi, _("\
+  cmd_list_element *reverse_stepi_cmd
+    = add_com ("reverse-stepi", class_run, reverse_stepi, _("\
 Step backward exactly one instruction.\n\
-Argument N means do this N times (or till program stops for another reason).")
-	   );
-  add_com_alias ("rsi", "reverse-stepi", class_run, 0);
+Argument N means do this N times (or till program stops for another reason)."));
+  add_com_alias ("rsi", reverse_stepi_cmd, class_run, 0);
 
-  add_com ("reverse-nexti", class_run, reverse_nexti, _("\
+  cmd_list_element *reverse_nexti_cmd
+    = add_com ("reverse-nexti", class_run, reverse_nexti, _("\
 Step backward one instruction, but proceed through called subroutines.\n\
-Argument N means do this N times (or till program stops for another reason).")
-	   );
-  add_com_alias ("rni", "reverse-nexti", class_run, 0);
+Argument N means do this N times (or till program stops for another reason)."));
+  add_com_alias ("rni", reverse_nexti_cmd, class_run, 0);
 
-  add_com ("reverse-continue", class_run, reverse_continue, _("\
+  cmd_list_element *reverse_continue_cmd
+    = add_com ("reverse-continue", class_run, reverse_continue, _("\
 Continue program being debugged but run it in reverse.\n\
 If proceeding from breakpoint, a number N may be used as an argument,\n\
 which means to set the ignore count of that breakpoint to N - 1 (so that\n\
 the breakpoint won't break until the Nth time it is reached)."));
-  add_com_alias ("rc", "reverse-continue", class_run, 0);
+  add_com_alias ("rc", reverse_continue_cmd, class_run, 0);
 
   add_com ("reverse-finish", class_run, reverse_finish, _("\
 Execute backward until just before selected stack frame is called."));