An Event-B Plug-in for Creating Deadlock-Freeness Theorems

This paper presents DFT-generator, a small tool to generate DeadlockFreeness Theorems (DFT) in Event-B specifications. Event-B, a companion to the B-method, allows specifiers to model systems and environments with the help states, invariants, and events. Events are guarded generalized substitutions which are fired non-deterministically. Assessing temporal properties such as termination or as non-blocking cycle is then a necessity. To overcome the lack of deadlock checking in the core of Event-B and of its supporting environment, Rodin, we have developed a practical little tool which generates the necessary theorems to prove that a model is free of deadlocks. We explain what are the deadlock theorems, why we need a tool to help generating the theorems, what problems were encountered during development. We conclude on a quick comparison with model-checking.