Verification of Heap Manipulating Programs with Ordered Data by Extended Forest Automata

We present a general framework for verifying programs with complex dynamic linked data structures whose correctness depends on ordering relations between stored data values. Our framework is based on the notion of forest automata (FA) previously developed for verification of heap-manipulating programs. We extend FA by constraints between data elements associated with nodes of the heaps represented by FA, and we propose necessary modifications of all the operations needed for a use of the extended FA in a fully-automated verification approach, based on abstract interpretation. We have implemented our approach as an extension of the Forester tool, and applied it to a number of programs dealing with data structures such as various forms of singly- and doubly-linked lists, binary search trees, as well as skip lists. The experiments show that our approach is not only fully automated, rather general, but also quite efficient.