C++ Component Model Re-Engineering By Automatic Transformation

Reengineering legacy software to use a modern component model can be accomplished by repeatedly applying a large number of semantically-sensitive program transformations, some of which synthesize new code structures, while others modify legacy code and meld it into the new framework. Using machinery that automates the process conquers the problems of massive scale, soundness, and regularity, and furthermore reduces time to completion by overlapping the project’s design and implementation phases. This article describes experiences in automating the reengineering of a collection of avionics components to conform to a Common Object Request Broker Architecture-like component framework, using Design Maintenance System, a program analysis and transformation system designed for building software engineering tools for large systems. Automated program transformation holds promise for a variety of software life-cycle endeavors, particularly where the size of legacy systems makes code analysis, reengineering, and evolution very difficult and expensive. But constructing transformation tools that handle the full generality of modern languages and that scale to very large applications is itself a painstaking and expensive process. This cost can be managed by developing a common transformation system infrastructure that is reused by an array of derived tools that each address specific tasks, thus leveraging the infrastructure cost over the various tools. This article describes how the Design Maintenance System (DMS) tool-building infrastructure was employed to construct the Boeing Migration Tool (BMT), a custom, component-modernization application being applied to a large C++ industrial avionics system. The BMT automatically transforms components developed under a 1990s era component style to a more modern Common Object Reques