A lightweight visualization of interprocedural data-flow paths for source code reading

To understand the behavior of a program, developers must read source code fragments in various modules. For developers investigating data-flow paths among modules, a call graph is too abstract since it does not visualize how parameters of method calls are related to each other. On the other hand, a system dependence graph is too fine-grained to investigate interprocedural data-flow paths. In this research, we propose an intermediate-level of visualization; we visualize interprocedural data-flow paths among method parameters and fields with summarized intraprocedural data-flow paths. We have implemented our visualization as an Eclipse plug-in for Java. The tool comprises a lightweight data-flow analysis and an interactive graph viewer using fractal value to extract a small subgraph of data-flow related to variables specified by a developer. A case study has shown our visualization enabled developers to investigate more data-flow paths in a fixed time slot. In addition, we report our lightweight data-flow analysis can generate precise data-flow paths for 98% of Java methods.