臺灣博碩士論文加值系統

中文摘要 為了達到跨平台的特性，Java程式會被編譯成一種以堆疊操
作為導向，與硬體無關的中間型式，這種中間型式稱為bytecode，執行
bytecode的工具是直譯器。Java程式語言雖然能符合在網路環境下發展程
式的特性，但用直譯器執行bytecode的過程十分緩慢，其速度無法和傳統
語言如C和C++相比。為了改善效能問題，因此產生了Java JIT編譯器（
Just-In-Time compiler, JIT compiler）。 我們研發的JIT編譯器架
構在Gabi系統上，是在run-time編譯bytecode為硬體相關的x86機器碼，
並轉換bytecode堆疊的動作為暫存器導向的操作型式。本文將詳細介紹
Java的執行環境，與JIT編譯器的理論，並提出虛擬堆疊技術做為JIT編譯
器實作的方法。最後會將此方法與SUN提出的JIT編譯器做效能比較，然後
討論影響執行效能的原因。

Abstract For the purpose of platform-independent, a Java
program is compiled to an intermediate form, bytecode, which is
stack-oriented and hardware-independent. The bytecode is
interpreted, the performance of such an interpreter is less
comparable to object coded generated by programming languages
such as C and C++. To improve the performance of interpreter, a
Java Just-In-Time compiler (JIT compiler) is required. The
JIT compiler, developed in this thesis, translates bytecode into
hardware-dependent machine code for x86 platform at run time.
The Java execution environment, the basis of JIT compiler, and
using virtual stack technique to implement JIT compiler are
illustrated. Finally, we will compare the performance of our JIT
compiler with SUN JIT compiler, and discuss the factors that
affect performance.