On the Veri cation of SCOOP Programs

In this paper we focus on the development of a toolbox for the veri cation of programs in the context of SCOOP an elegant concurrency model, recently formalized based on Rewriting Logic (RL) and Maude. SCOOP is implemented in Ei el and its applicability is demonstrated also from a practical perspective, in the area of robotics programming. Our contribution consists in devising and integrating an alias analyzer and a Co man deadlock detector under the roof of the same RL-based semantic framework of SCOOP. This enables using the Maude rewriting engine and its LTL model-checker for free , in order to perform the analyses of interest. We discuss the limitations of our approach for model-checking deadlocks and provide solutions to the state explosion problem. The latter is mainly caused by the size of the SCOOP formalization which incorporates all the aspects of a real concurrency model. On the aliasing side, we propose an extension of a previously introduced alias calculus based on program expressions, to the setting of unbounded program executions such as in nite loops and recursive calls. Moreover, we devise a corresponding executable specication easily implementable on top of the SCOOP formalization. An important property of our extension is that, in non-concurrent settings, the corresponding alias expressions can be over-approximated in terms of a notion of regular expressions. This further enables us to derive an algorithm that always stops and provides a sound over-approximation of the may aliasing information, where soundness stands for the lack of false negatives.