New Generation Computing, 20(2002)101-124
Ohmsha, Ltd. and Springer-Verlag

A Portable Approach to Dynamic Optimization in Run-time Specialization

Hidehiko MASUHARA
Department of Graphics and Computer Science
Graduate School of Arts and Sciences, The University of Tokyo
masuhara@acm.org

Akinori YONEZAWA
Department of Computer Science, The University of Tokyo
yonezawa@is.s.u-tokyo.ac.jp

Received 18 June 2001
Revised manuscript received 28 July 2001

Abstract

This paper proposes a run-time bytecode specialization (BCS) technique that analyzes programs and generates specialized programs at run-time in an intermediate language. By using an intermediate language for code generation, a back-end system can optimize the specialized programs after specialization. The system uses Java virtual machine language (JVML) as the intermediate language, which allows the system to easily achieve practical portability and to use existing sophisticated just-in-time (JIT) compilers as its back-end. The binding-time analysis algorithm is based on a type system, and covers a non-object-oriented subset of JVML. The specializer generates programs on a per-instruction basis, and can perform method inlining at run-time. Our performance measurements show that a non-trivial application program specialized at run-time by BCS runs approximately 3-4 times faster than the unspecialized one. Despite the large overhead of JIT compilation of specialized code, we observed that the overall performance of the application can be improved.

Keywords: Program Specialization, Partial Evaluation, Run-time Code Generation, Just-In-Time Compilation, Java Virtual Machine Language, Intermediate Language.

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