Design, implementation, and evaluation of optimizations in a Java (TM) Just-in-Time compiler

The Java language incurs a runtime overhead for exception checks and object accesses, which are executed without an interior pointer in order to ensur e safety. It also requires type inclusion test, dynamic class loading, and dynamic method calls in order to ensure flexibility, A 'Just-In-Time' (JIT) compiler generates native code from Java byte code at runtime. It must imp rove the runtime performance without compromising the safety and flexibilit y of the Java language. We designed and implemented effective optimizations for a JIT compiler, such as exception check elimination, common subexpress ion elimination, simple type inclusion test, method inlining, and devirtual ization of dynamic method call, We evaluate the performance benefits of the se optimizations based on various statistics collected using SPECjvm98, its candidates, and two JavaSoft applications with byte code sizes ranging fro m 23 000 to 280 000 bytes, Each optimization contributes to an improvement in the performance of the programs, Copyright (C) 2000 John Wiley & Sons, L td.