Experience Report: Rapid Reengineering of Legacy Software using Java Reflection

The objective of this paper is to describe our experience in rapidly reengineering legacy software through the application of Java reflection in a research compiler. This process would be of value to language evolution and development e↵orts, in general, and reengineering e↵orts, in particular. It was performed in the course of a software project that has slowly evolved from a simple language translator to a sophisticated verifying compiler with multiple back-ends over a 20-year period, even as the language itself has continued to change with research progress. To minimize the temporal costs of refactoring legacy code in the face of continuous evolution of the language and the need for new additional components (e.g., translators for multiple languages) for various uses in our project, we used a reflection-based, generic walker based on a proper implementation of the visitor pattern. This paper describes the dynamic walker and our experience in employing the walker for code generation.