How to alter control flow

[Rukayat A Erinfolami]

How do I go about altering the control flow of a program running in Qemu's
user mode emulation. For instance, at the callsite of function A::f(), I
want A::f() and all the definitions of f() by the derived classes of A to
be executed. So if B derives from A, I want to execute both A::f() and
B::f() at that callsite.