Get the C++ member function and the corresponding offset via LLVM IR

Question

I would like to have an overall analysis for c++ classes, and I want to know each member function's offset. Could anyone give me any hint on how to get those information in LLVM IR? I would appreciate any help from you.

A code example could be:

class Circle {
    int radius;
public:
    void setRadius(int _radius){radius = _radius;}
    int getRadius() {return radius;}
};

I would like to know that 1st field is an integer, the 2nd and 3rd field is a member function, and also the definition of the member function.

Answer 1

There's not really such a thing as a "member function's offset". Functions can be totally optimized away as is the case here . You can take a look at the IR here and it's essentially the same thing. Virtual functions will have an offset into a vtable, but that's another matter.

You can force there to be an address by taking a pointer to a function. You could then calculate an "offset", but relative to what exactly? Not sure there's any guarantee from LLVM how member functions are placed in the text segment.