Descriptor for a local of a method
        internal int CreateLocal(string name, PERWAPI.Type type) {
            int local;
            if (unused_locals.ContainsKey(type) && unused_locals[type].Count > 0) {
                local = unused_locals[type].Pop();
            } else {
                Local loc = new Local(name, type);
                CLRLocals.Add(loc);
                local = CLRLocals.Count - 1;
            }

            locals_inuse.Add(local);
            return local;
        }