Constructing Structured SSA from FJ

We propose a novel approach of constructing structured SSA forms. Specifically, our declarative algorithm converts a Featherweight Java (FJ) program into its structured SSA form in a single pass. We prove that the proposed algorithm produces valid SSA forms which are semantically consistent with respect to the original source programs. We verify the resulting SSA forms are minimal. We demonstrate that structured SSA form can serve as a unified intermediate representation for both compiler optimization and program verification pipelines. We implemented the algorithm as a library.