Exchanging information in cooperative software validation

Cooperative software validation aims at having verification and/or testing tools cooperate on the task of correctness checking. Cooperation involves the exchange of information about currently achieved results in the form of (verification) artifacts. These artifacts are typically specialized to the type of analysis performed by the tool, e.g., bounded model checking, abstract interpretation or symbolic execution, and hence require the definition of a new artifact for every new cooperation to be built. In this article, we introduce a unified artifact (called Generalized Information Exchange Automaton, short GIA) supporting the cooperation of over-approximating with under-approximating analyses. It provides information gathered by an analysis to its partner in a cooperation, independent of the type of analysis and usage context within software validation. We provide a formal definition of this artifact in the form of an automaton together with two operators on GIAs. The first operation reduces a program by excluding these parts, where the information that they are already processed is encoded in the GIA. The second operation combines partial results from two GIAs into a single on. We show that computed analysis results are never lost when connecting tools via these operations. To experimentally demonstrate the feasibility, we have implemented two such cooperation: one for verification and one for testing. The obtained results show the feasibility of our novel artifact in different contexts of cooperative software validation, in particular how the new artifact is able to overcome some drawbacks of existing artifacts.