Advanced automata-based algorithms for program termination checking

Abstract

In 2014, Heizmann et al. proposed a novel framework for program termination analysis. The analysis starts with a termination proof of a sample path. The path is generalized to a Büchi automaton (BA) whose language (by construction) represents a set of terminating paths. All these paths can be safely removed from the program. The removal of paths is done using automata difference, implemented via BA complementation and intersection. The analysis constructs in this way a set of BAs that jointly "cover" the behavior of the program, thus proving its termination. An implementation of the approach in Ultimate Automizer won the 1st place in the Termination category of SV-COMP 2017.