A calculus of atomic actions

We present a proof calculus and method for the static verification of assertions and procedure specifications in shared-memory con-current programs. The key idea in our approach is to use atom-icity as a proof tool and to simplify the verification of assertions by rewriting programs to consist of larger atomic actions. We pro-pose a novel, iterative proof style in which alternating use of ab-straction and reduction is exploited to compute larger atomic code blocks in a sound manner. This makes possible the verification of assertions in the transformed program by simple sequential rea-soning within atomic blocks, or significantly simplified application of existing concurrent program verification techniques such as the Owicki-Gries or rely-guarantee methods. Our method facilitates a clean separation of concerns where at each phase of the proof, the user worries only about only either the sequential properties or the concurrency control mechanisms in the program. We implemented our method in a tool called QED. We demonstrate the simplicity and effectiveness of our approach on a number of benchmarks includ-ing ones with intricate concurrency protocols