Virtual Dispatch During Construction

Consider the following C++ program:

#include <iostream>

struct Base {
    Base() { whoami(); }
    virtual void whoami() { std::cout << "Base\n"; }
    virtual ~Base() = default;
};

struct Derived : Base {
    void whoami() override { std::cout << "Derived\n"; }
};

int main() {
    Derived d;
}

What happens when this program runs?