Optimizing direct threaded code by selective inlining

Abstract

Achieving good performance in bytecoded language interpreters is difficult without sacrificing both simplicity and portability. This is due to the complexity of dynamic translation (`just-in-time compilation') of bytecodes into native code, which is the mechanism employed universally by high-performance interpreters. We demonstrate that a few simple techniques make it possible to create highly-portable dynamic translators that can attain as much as 70% the performance of optimized C for certain numerical computations. Translators based on such techniques can offer respectable performance without sacrificing either the simplicity or portability of much slower `pure' bytecode interpreters.