parse-events: Support '+' opcode in print format

The '+' opcode is not supported in the arguments for the print format.
This patch adds support for it.

Cc: Michael Rubin <mrubin@google.com>
Cc: David Sharp <dhsharp@google.com>
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Link: http://lkml.kernel.org/r/1310785241-3799-4-git-send-email-vnagarnaik@google.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arun Sharma <asharma@fb.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

tools/lib/traceevent/event-parse.c

@@ -2047,6 +2047,18 @@ static int arg_num_eval(struct print_arg *arg, long long *val)
 				break;
 			*val = left - right;
 			break;
+		case '+':
+			if (arg->op.left->type == PRINT_NULL)
+				left = 0;
+			else
+				ret = arg_num_eval(arg->op.left, &left);
+			if (!ret)
+				break;
+			ret = arg_num_eval(arg->op.right, &right);
+			if (!ret)
+				break;
+			*val = left + right;
+			break;
 		default:
 			do_warning("unknown op '%s'", arg->op.op);
 			ret = 0;