Techniques are provided for converting a circuit design file so that it is compatible with a new programmable IC. Black box declarations and instances of black boxes in the circuit design file are located automatically. Then, information about the function and structure of the black boxes is gathered from various user files. This information is used to convert the black box declarations and instances into equivalent declarations and instances that are compatible with the new programmable IC. The design conversion process is performed quickly and automatically with minimal user input. User input is only needed to identify recognized black boxes.