静动态结合的Java程序不变性分析方法.docVIP

静动态结合的Java程序不变性分析方法 于利前 王林章 雷斌 赵建华 李宣东 (南京大学 计算机软件新技术国家重点实验室 南京 210093) (南京大学 计算机科学与技术系 南京 210093) 摘 要: 程序的不变性（Immutability）是指类的实例对象在其生命周期内状态不会发生改变。不变性信息可以用来指导程序的分析、测试和验证等工作。分析程序的不变性主要有两种技术：一种是采用静态分析技术分析对象式程序的类、属性和方法等，获得程序不变性性质；另一种是通过观察程序运行时各个对象的状态变化来判断程序的不变性性质。静态分析具有可自动化、效率高等优点，但是因为静态分析采取保守的分析策略，使得分析的精度不高。动态分析可以准确地观察对象的状态变化，但是分析的结果不完备，并且因为要多次运行程序，开销高。现有分析不变性的技术主要集中于对程序的静态分析，而动态分析方面的工作很少。本文在分析了静、动态分析技术各自的优缺点后，提出了一种静动态结合的混合分析技术。首先通过对程序进行静态分析以获得初步的程序不变性信息，然后对静态分析的结果中不确定的部分再进行动态分析，同时动态分析还可以用于对静态分析结果的验证。静动态结合的分析技术比单纯的静态分析提高了分析结果的精度，同时也降低了单纯用动态分析的开销，提高了效率。 关键词: 不变性；静态分析；动态分析；混合分析 中图法分类号: TP311 Combined Static and Dynamic Immutability Analysis of Java Program YU Li-Qian WANG Lin-Zhang LEI Bin ZHAO Jian-Hua LI Xuan-Dong (State Key Laboratory of Novel Software Technology, Nanjing University, Nanjing 210093) (Department of Computer Science and Technology, Nanjing University, Nanjing 210093) Abstract: An object is immutable if its state cannot be changed during its life cycle. This characteristic of object is called immutability. The immutability information can be applied to conduct program analysis, testing, verification, and so on. The analysis techniques of object immutability can be classified into two categories: One is static analysis, the other is dynamic analysis. Static analysis can be automatic, but since it considers conservative conditions, its precision is not high. Dynamic analysis will run a program to observe the changes of object states, so it can report an object is mutable whenever its state is changed. But dynamic analysis is not complete, even if the state of an object is not changed during many times of program execution, we can not conclude that the object is immutable. Also the dynamic analysis costs a lot. Consider both the advantages and disadvantages of static analysis and dynamic analysis