Computation and visualization of cause-effect paths

Static analyzers detect possible run-time errors at compile-time and often employ data-flow analysis techniques to infer properties of programs. Usually, dataflow analysis tools report possible errors with line numbers in source code and leave the task of locating root causes of errors. This paper proposes a technique to aid developers in locating the root causes of statically identified run-time errors with the help of cause-effect paths. A cause effect path terminates at an erroneous statement and originates at the statement which is responsible for the error. We propose modifications to the classic data-flow analysis algorithm to compute cause-effect paths. We discuss different visualization modes in which cause-effect paths can be displayed. As a case study, we implemented a null pointer analyzer, with the additional capability of cause-effect path computation, using the Microsoft Phoenix framework. In addition, we propose a methodology to automatically generate an analyzer which computes cause-effect paths using a framework such as Microsoft Phoenix.