Runtime Code Generation with JVM and CLR

Modern bytecode execution environments with optimizing just-in-time compilers, such as Sun’s Hotspot Java Virtual Machine, IBM’s Java Virtual Machine, and Microsoft’s Common Language Runtime, provide an infrastructure for generating fast code at runtime. Such runtime code generation can be used for efficient implementation of parametrized algorithms. More generally, with runtime code generation one can introduce an additional binding-time without performance loss. This permits improved performance and improved static correctness guarantees. We report on several experiments with runtime code generation on modern execution platforms. In particular, we show how to introduce C#-style delegates in Java using runtime code generation, to avoid most of the overhead of wrapping and unwrapping method arguments and method results usually incurred by reflective method calls. Furthermore, we give a high-speed implementation of the Advanced Encryption Standard (AES, also known as Rijndael) in C# using runtime code generation. Finally, we experiment with sparse matrix multiplication using runtime code generation on both platforms.