Search based hierarchy generation for reverse engineered state machines

Abstraction is a valuable tool that can play an important role in reducing the cost of maintenance of software systems. Despite the cost reduction abstract documentation can provide, the cost of generating documentation that offers an implementation-independent overview of the system often outweighs it. This has been the motivating force for tools and techniques that reduce the cost of documentation generation, including this work. State machines offer an ideal level of abstraction and techniques to infer them from machines are already mature. Despite this, the abstraction state machines provide is restricted as they become unmanageable when they are of any significant size. As a result, inference tools are only ideal for those who are already familiar with the system. This work focuses on making state machines useful for larger systems. In order to do so the complexity of a machine needs to be reduced; this is realised by introducing a hierarchy to the machine, making them closer to Harel's Statechart formalism (without concurrency).