MiniJava on RISC-V: A Game of Global Compilers Domination

Over two decades have passed since the first publication of Modern Compiler Implementation by Andrew Appel, with its second edition revised by Jens Palsberg. This textbook remains an essential guide for students, hobbyists, and researchers navigating the complexities of compiler construction. Despite this venerable textbook, designing a course on programming language compiler construction is a challenging task due to the intricate handling of syntax, semantics, and optimization processes it involves. Students often enter compiler courses with limited knowledge of object-oriented languages, dynamic dispatch, and low-level assembly. Given the limited instruction time, educators find it more beneficial to focus on transferable skills rather than the intricacies of a particular instruction set architecture (ISA). While many computer science graduates may not work directly with low-level hardware or software, the concepts learned in compiler courses are crucial for a comprehensive understanding of programming languages. This paper presents the work to keep the elegant MiniJava educational compiler relevant and modernized, including the implementation of a new instruction selection phase from Appel and Palsberg’s Modern Compiler Implementation (2e) to support current RISC-based targets. Our work targets another well-used educational platform, Embedded Xinu, as the operating system, allowing students to run their compiler output directly on RISC-based development boards that leverage their learning from prior systems courses, and negating the need for simulators, emulators, or virtual machines. Finally, we add a minimal garbage collector suitable for upper-level undergraduates and beginning graduate students to understand and experiment with. We plan to run the RISC-V MiniJava compiler assignments during the Fall 2024 semester.