Dynamic slicing of distributed programs

As software applications grow larger and become more complex, program maintenance activities such as adding new functionality, debugging, and testing consume an increasing amount of available resources for software development. This is especially true for distributed systems communicating via message passing. In order to cope with this increased complexity, programmers need effective computer supported methods for decomposition and dependence analysis of programs. Program slicing is one method for such decomposition and dependence analysis. A program slice with respect to a specified variable at some program point consists of those parts of the program which potentially affect the value of that variable at the particular program point. A static slice is valid for all possible executions of a program while a dynamic slice considers only a particular execution of a program. In this paper we present a technique for dynamic slicing of distributed programs which computes accurate slices. We introduce the notion of distributed dynamic dependence graph (DDDG) which represents control, data and communication dependences in a distributed program. This graph is built at run time and used to compute dynamic slices of the program. A distributed dynamic slicer for ANSI-C programming language has been implemented on a parallel MIMD computer of type Parsytec GC/Powerplus with 128 PowerPC processors.