Abstract Interpretation with Unfoldings

Interpretation with Unfoldings⋆ Marcelo Sousa, César Rodŕıguez, Vijay D’Silva and Daniel Kroening 1 University of Oxford, United Kingdom 2 Université Paris 13, Sorbonne Paris Cité, LIPN, CNRS, France 3 Google Inc., San Francisco Abstract. We present and evaluate a technique for computing pathsensitive interference conditions during abstract interpretation of concurrent programs. In lieu of fixed point computation, we use prime event structures to compactly represent causal dependence and interference between sequences of transformers. Our main contribution is an unfolding algorithm that uses a new notion of independence to avoid redundant transformer application, thread-local fixed points to reduce the size of the unfolding, and a novel cutoff criterion based on subsumption to guarantee We present and evaluate a technique for computing pathsensitive interference conditions during abstract interpretation of concurrent programs. In lieu of fixed point computation, we use prime event structures to compactly represent causal dependence and interference between sequences of transformers. Our main contribution is an unfolding algorithm that uses a new notion of independence to avoid redundant transformer application, thread-local fixed points to reduce the size of the unfolding, and a novel cutoff criterion based on subsumption to guarantee termination of the analysis. Our experiments show that the abstract unfolding produces an order of magnitude fewer false alarms than a mature abstract interpreter, while being several orders of magnitude faster than solver-based tools that have the same precision.interpreter, while being several orders of magnitude faster than solver-based tools that have the same precision.