Object-Based Dynamic Protocol Recovery for Multi-Threading Programs

A protocol defines the sequencing constraints for the operations that can be applied to an object. Quante introduced a protocol recovery technique that is able to extract protocols from existing software by means of dynamic analysis. This approach represents the behavior as object process graphs (OPG). OPGs are a projection of the control flow graph reduced to the operations relevant to an individual object. The protocol is inferred from a set of OPGs. The extraction was designed to handle sequential programs only. As multi-core architectures and, hence, multi-threading becomes more and more common in nowadays programming, it is necessary to extend reverse engineering techniques for multi-threaded programs. In this paper, we extend Quante's approach to protocol reconstruction for programs with multiple threads. We are formalizing this process using concepts from automata theory, namely, product and shuffle automata. We present a naive approach to combine these concepts and a combined approach. Our evaluation for realistic Java programs demonstrates the scalability of the combined approach and the combinatorial explosion of the naive approach.