Typical Type C Message Implementation

I’m interested in what a typical (or at least Apple) implementation of the Objective C dynamic messaging system looks like. How selectors are processed at compilation and runtime, which really means NSObject*how the method implementation is implemented.

In C ++, we have virtual functions; how they are implemented is officially an implementation detail, but in fact, the VF table pointer as the first data item is largely data. I am wondering if there is a similar ubiquitous way to implement the ObjC class system.