helper/command: pass command arguments also as Jim_Obj

Some OpenOCD command gets fragment of TCL scripts as command-line
argument, fragments that will be kept and executed later on.
E.g. the command 'configure' gets the body of an OpenOCD event:
	$TARGET configure -event halted {TCL code}

These commands store the argument as a Jim_Obj and pass it to the
jimtcl interpreter when the TCL fragment has to be executed.
Using Jim_Obj as storage is relevant to let the jimtcl interpreter
to recover extra info of the TCL fragment, like the file-name and
the line-number that contain the fragment, that will be printed
out in case of run-time errors.

While converting the commands to COMMAND_HANDLER, we should avoid
storing the argument as C strings otherwise we will loose precious
info in case of run-time errors making challenging the debugging
of such TCL fragments.

Extend the struct command_invocation to contain the array that
points to the Jim_Obj of the command arguments.
This will be used while converting commands to COMMAND_HANDLER.

Change-Id: If37c5f20e9a71349f77ba1571baf1e6778e28aa5
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/8057
Tested-by: jenkins

doc/manual/helper.txt

@@ -79,6 +79,8 @@ command handlers and helpers:
 - @c CMD_NAME - invoked command name
 - @c CMD_ARGC - the number of command arguments
 - @c CMD_ARGV - array of command argument strings
+- @c CMD_JIMTCL_ARGV - array containing the Jim_Obj equivalent of command
+  argument in @c CMD_ARGV.
 
 @section helpercmdregister Command Registration
 

src/helper/command.c

@@ -511,6 +511,7 @@ static int exec_command(Jim_Interp *interp, struct command_context *context,
 		.name = c->name,
 		.argc = argc - 1,
 		.argv = words + 1,
+		.jimtcl_argv = argv + 1,
 	};
 
 	cmd.output = Jim_NewEmptyStringObj(context->interp);

src/helper/command.h

@@ -79,6 +79,7 @@ struct command_invocation {
 	const char *name;
 	unsigned argc;
 	const char **argv;
+	Jim_Obj * const *jimtcl_argv;
 	Jim_Obj *output;
 };
 
@@ -153,6 +154,11 @@ void *jimcmd_privdata(Jim_Cmd *cmd);
  * rather than accessing the variable directly.  It may be moved.
  */
 #define CMD_ARGV (cmd->argv)
+/**
+ * Use this macro to access the jimtcl arguments for the command being
+ * handled, rather than accessing the variable directly.  It may be moved.
+ */
+#define CMD_JIMTCL_ARGV (cmd->jimtcl_argv)
 /**
  * Use this macro to access the name of the command being handled,
  * rather than accessing the variable directly.  It may be moved.