lol_abi.cpp

int add_example(int a, int b);
template <> struct std::call_abi<add_example> {
  // caller_stub is force-inlined into everyone who calls add_example:
  int &caller_stub(int a, int b) {
    regs.rdi = (uint64_t)a;
    regs.rsi = (uint64_t)b;
    callee_stub();
    return regs.rax;
  }
  void callee_stub() {
    int a = (int)regs.rdi;
    int b = (int)regs.rsi;
    // this calls the actual body of my_function (also inlined):
    int ret = impl(a, b);
    regs.rax = ret;
  }
};


MyBigType struct_return_example(int arg);

template <> struct std::call_abi<struct_return_example> {
  MyType &caller_stub(int arg) {
    MyType *tmp = alloca_in_caller_frame<MyType>();
    regs.rdi = (uint64_t)tmp;
    regs.rsi = (uint64_t)arg;
    callee_stub();
    return *tmp;
  }
  void callee_stub() {
    MyType *tmp = (MyType *)regs.rdi;
    int arg = (int)regs.rsi;
    // add guaranteed copy elision for this
    new (tmp) MyType(impl(arg));
  }
};