MFC uses an efficient way to deal with space consumption and complexity issues involved with virtual functions. For examples, the image below demonstrates how functions in the class hierarchy are fetched. This implementation is space efficient, easy to understand, and also seems to be efficient.

![MFC Message Map Processing](https://i.stack.imgur.com/pWERb.png)

My question is, why core C++ doesn't use the same way to reduce the complexity of compiler and to get rid of vtables? Perhaps this implemention has efficiency issues as well?