auto hardware = GetTargetAnnotation(op);
      if (!hardware) return;
      float cost = GetCostForOp(op, *hardware);
      UpdateCost(op, cost, &builder);
    }
  });
}

}  // namespace

float GetCostForOp(Operation* op, const std::string& hardware) {
  auto* device_hardware = GetTargetHardware(hardware);
  if (device_hardware == nullptr) {

// analyze the cost.

// ================== Interface  ========================

// Get the estimated cost for the op under the given hardware spec senario.
float GetCostForOp(Operation* op, const std::string& hardware);

// Get the estimated cost for the whole function under the given hardware.
float GetCostForFunc(func::FuncOp* func, const std::string& hardware);