Generating design data for manufacturing a logic array of a semiconductor circuit from specification data describing the logic array. The specification is transformed into structured specification data including objects corresponding to circuit cells of a first type and logic specification data specifying the logic circuitry to be included in the logic array, and into structure data including placing and routing information concerning the circuit cells of the first type. A determination is made of circuit cells of a second type from the logic specification data. The circuit cells of the first type are pre-placed and routed based on the structure data. The circuit cells of second type are automatically placed and routed.