I don't understand why being in the same or a separate project matters at all. It's an entirely theoretical thing. The only actual meaningful question is if it

I don't understand why being in the same or a separate project matters at all. It's an entirely theoretical thing. The only actual meaningful question is if it is in the same shared library or not (and it isn't). Your CPU does not care that function A comes from company A and function B from company A or B when executing, it'll be the same code.