Precise slicing of interprocedural concurrent programs

摘要

Program slicing is an effective technique for analyzing concurrent programs. However, when a conventional closure-based slicing algorithm for sequential programs is applied to a concurrent interprocedural program, the slice is usually imprecise owing to the intransitivity of interference dependence. Interference dependence arises when a statement uses a variable defined in another statement executed concurrently. In this study, we propose a global dependence analysis approach based on a program reachability graph, and construct a novel dependence graph called marking-statement dependence graph (MSDG), in which each vertex is a 2-tuple of program state and statement. In contrast to the conventional program dependence graph where the vertex is a statement, the dependepce relation in MSDG is transitive. When traversing MSDG, a precise slice will be obtained. To enhance the slicing efficiency without loss of precision, our slicing algorithm adopts a hybrid strategy. The procedures containing interaction statements between threads are inlined and sliced by the slicing algorithm based on program reachability graphs while allowing other procedures to be sliced as sequential programs. We have implemented our algorithm and three other representative slicing algorithms, and conducted an empirical study on concurrent Java programs. The experimental results show that our algorithm computes more precise slices than the other algorithms. Using partial-order reduction techniques, which are effective for reducing the size of a program reachability graph without loss of precision, our algorithm is optimized, thereby improving its performance to some extent.