Not all programs are compiled from source code. AGI architectures are often written in LISP or Prolog, which are interpreted. They typically have their key knowledge structures, such as their goals and some of their algorithms, encoded in data structures. It's unclear whether they would need to rewrite any code to recursively self-improve. It probably depends on particulars of the logic used. Hence this post.

I'm going to delete the footnote your initial comment referred to, because it's a distraction.