[Fyren]

The compiler would have the definition of the class and so would know the size whenever you construct one. If you look at the disassembly for an object constructed on the heap, you'll see a call to new with its size (unless it's placement new, I guess).

I guess you could try to sigscan for a call to new that you know is for a class you want to get the size at runtime. I don't really have any other ideas besides maintaining your own definition of the class.