I don't think it will mostly be a coding problem. I think there'll be some algorithms, potentially quite complicated ones, that one will wish to implement at high speed, preferably with reproducible results (even in the face of multithreading and locks and such). And there will be a problem of reflecting on that code, and having the AI prove things about that code. But mostly, I suspect that most of the human-shaped content of the AI will not be low-level code.