Ábaco: um interpretador jit de Visual Basic 6 para a modernização de sistemas legado

Abstract

Numerous Brazilian organizations still depend on legacy systems developed in languages whose ecosystems have become obsolete, such as Visual Basic 6.0 (VB6). Released in 1998 and without official support since 2008, the maintenance of this technology in modern environments is severely limited by the proprietary nature of its compiler and the impossibility of acquiring new licenses. This work presents the development of Ábaco, an open-source VB6 interpreter written in Rust, designed to facilitate the modernization of these systems. Unlike the original environment, Ábaco aims to establish a technical foundation that enables the future implementation of modern features, such as parallel execution and flexible integration with external libraries, while offering compatibility with legacy codebases. The implementation methodology covers the entire execution pipeline - loading, syntactic analysis, and assembly, through Just-In-Time (JIT) compilation for the 32-bit x86 architecture - with no external dependencies beyond the operating system. The results demonstrate that the system is already capable of executing a subset of the VB6 language, establishing a solid foundation for total compatibility and the extension of functionalities in legacy systems.