1. A method comprising: loading a programming language source code description, the programming language source code description describing logic in a design for an integrated circuit; identifying one or more variables in the programming language source code description, the one or more variables comprising variables that are to be assigned to one or more respective interface resources; receiving user input, the user input selecting at least one of the one or more respective interface resources to be assigned to the one or more variables in the programming language source code description; and with a computer, generating one or more register-transfer level descriptions of the logic based at least in part on the programming language source code description and incorporating the at least one respective interface resources selected by the user input.