Characterization and automatic identification of type infeasible call chains

Many software engineering applications utilize static program analyses to gain information about programs. Some applications perform static analysis over the whole program's call graph, while others are more interested in speci c call chains within a program's call graph. A particular static call chain for an object-oriented program may in fact be impossible to execute, or infeasible, such that there is no input for which the chain will be taken. Identifying infeasible static call chains can save time and resources with respect to the targeted software development tool. This paper examines type infeasibility of call chains, which may be caused by inherently polymorphic call sites and are sometimes due to imprecision in call graphs. The problem of determining whether a call chain is type infeasible is de ned and exempli ed, and a key property characterizing type infeasible call chains is described. An empirical study was performed on a set of Java programs, and results from examining the call graphs of these programs are presented. Finally, an algorithm that automatically determines the type infeasibility of a call chain due to object parameters is presented.