Faster Variational Execution with Transparent Bytecode Transformation

TL;DR

This paper introduces a new bytecode transformation technique that enables faster variational execution on standard JVMs, significantly improving performance and sharing efficiency compared to previous interpreters.

Contribution

The paper presents a transparent bytecode transformation method that allows variational execution without modifying JVMs, achieving substantial speedups over existing interpreters.

Findings

Speedup of 2 to 46 times over state-of-the-art interpreters

High efficiency in sharing computations across configurations

Effective exploration of large configuration spaces

Abstract

Variational execution is a novel dynamic analysis technique for exploring highly configurable systems and accurately tracking information flow. It is able to efficiently analyze many configurations by aggressively sharing redundancies of program executions. The idea of variational execution has been demonstrated to be effective in exploring variations in the program, especially when the configuration space grows out of control. Existing implementations of variational execution often require heavy lifting of the runtime interpreter, which is painstaking and error-prone. Furthermore, the performance of this approach is suboptimal. For example, the state-of-the-art variational execution interpreter for Java, VarexJ, slows down executions by 100 to 800 times over a single execution for small to medium size Java programs. Instead of modifying existing JVMs, we propose to transform existing bytecode to make it variational, so it can be executed on an unmodified commodity JVM. Our evaluation shows a dramatic improvement on performance over the state-of-the-art, with a speedup of 2 to 46 times, and high efficiency in sharing computations.