Symbolic reachability analysis of FIFO-channel systems with nonregular sets of configurations
We address the verification problem of FIFO-channel systems. We apply the symbolic analysis principle to these systems. We represent their sets of configurations using structures called constrained queue-content decision diagrams (CQDDs) combining finite-state automata with linear arithmetical constraints on number of occurrences of symbols. We show that CQDDs allow forward and backward reachability analysis of systems with nonregular sets of configurations. Moreover, we prove that CQDDs allow to compute the exact effect of the repeated execution of any fixed cycle in the transition graph of a system. We use this fact to define a generic reachability analysis semi-algorithm parametrized by a set of cycles Theta. Given a set of configurations, this semi-algorithm performs a least fixpoint calculation to construct the set of its successors (or predecessors). At each step, this calculation is accelerated by considering the cycles in Theta as additional "meta-transitions" in the transition graph, generalizing the approach of Boigelot and Godefroid (CAV'96, Lecture Notes in Computer Science, Vol. 1102, Springer, Berlin, 1996). (C) 1999 Published by Elsevier Science B.V. All rights reserved.
symbolic reachability analysis fifo-channel systems verification automata infinite-state systems non-regular sets linear constraints