External Memory Search for Verification of Multi-threaded C++ Programs

With the advent of multi-core processors, the need for development of multi-threaded softwares has become indispensable. Verification of multi-threaded programs, particularly those that involve sharing of memory resources, poses a greater challenge than their sequential counterparts. A certain class of software model checking problems can be transformed to AI search problems in graphs. Search algorithms, such as DFS, BFS, A*, etc. can then be applied to find an erroneous program location in a given program. Unfortunately, verification of softwares is very memory intensive. In this paper, we equip the search algorithms used in model checking a C++ program, with a controlled access to secondary memory such as hard disk. We exploit the concept of a signature of a state that allows the full state vector to stay on secondary memory. The extended search algorithms are now able to solve larger problems that were unsolvable due to the memory bottleneck.