Static and dynamic C++ code analysis for the recovery of the object diagram

When a software system enters the maintenance phase, the availability of accurate and consistent information about its organization can help alleviate the difficulties of program understanding. Reverse engineering methods aim at extracting such information directly from the code. While several tools support the recovery of the class diagram from object oriented code, so far no work has attacked the problem of statically characterizing the behavior of an object oriented system by means of diagrams which represent the class instances (objects) and their mutual relationships. In this paper a novel static analysis algorithm is proposed for extraction of the object diagram from the code, based on a program representation called the object flow graph. Partial object diagrams can be associated dynamically to the system by executing and tracing the program on a set of test cases. The complementary nature of these two views is discussed, and a novel approach to object oriented testing is derived from such a comparison. The usefulness of the proposed technique is illustrated on a real world, public domain C++ system.