Optimizing java bytecode using the soot framework: Is it feasible

Abstract

This paper presents Soot, a framework for optimizing Java™ bytecode. The framework is implementedin Java andsu pports three intermediate representations for representing Java byte code: Baf, a stream lined representation of Java’s stack-based bytecode; Jimple, a typed three-address intermediate representation suitable for optimization; andGrim p, an aggregated version of Jimple. Our approach to class file optimization is to first convert the stack-based bytecode into Jimple, a three-address form more amenable to traditional program optimization, andt hen convert the optimized Jimple back to bytecode. In order to demonstrate that our approach is feasible, we present experimental results showing the effects of processing class files through our framework. In particular, we study the techniques necessary to effectively translate Jimple back to bytecode, without losing performance. Finally, we demonstrate that class file optimization can be quite effective by showing the results of some basic optimizations using our framework. Our experiments were done on ten benchmarks, including seven SPECjvm98 benchmarks, andw ere executedon five different Java virtual machine implementations.