Function Call Optimisation in SystemC Hardware Compilation

Functions are commonly used in SystemC and other high-level languages to divide code into separate tasks. During synthesis, a hardware compiler can instantiate logic for each function call. Alternatively, a function can be mapped to a separate piece of hardware that is shared between calls to the function. This process, called function exlining, can significantly improve logic usage of a design. This paper investigates the benefits of function exlining in hardware compilation and proposes a method for implementing this optimisation in SystemC. In this method, exlining is described as a source transformation which can be easily implemented in existing compiler frameworks. The method has been implemented in a commercial SystemC hardware compiler and experiments show that exlining function calls can significantly reduce the logic size of a design.