Semantic Differencing for Message-Driven Component & Connector Architectures

Stepwise refinement is a development methodology in which software components progressively evolve under strict adherence of proven properties. This requires means to check whether a new version of a component – with potentially different interface and behavior implementation – refines the behavior of its predecessor. Where architecture description languages (ADLs) support refinement checking, the complexity of their semantic domain requires (partially) manual proving to establish refinement between component versions. We identified a subset of the FOCUS semantics for describing distributed systems as stream processing functions that is powerful enough to model complex and realistic systems, yet sufficiently powerful to support fully automated refinement checking. Leveraging this, we present a refinement checking method for ADLs yielding semantics that can be expressed as stream processing functions. This method relies on transforming architectures into composed port automata and translating these to Buchi automata prior to proving refinement using RABIT for language inclusion checking. This method enables to compare the behaviors of component versions with minimal effort, yields witnesses for non-refining component pairs, and, thus, ultimately facilitates stepwise component refinement.