The JalapeÃño Dynamic Optimizing Compiler is a key component of the JalapeÃño Virtual Machine, a new Java Virtual Machine (JVM) designed to support efficient and scalable execution of Java applications on SMP server machines. This paper describes the design of the JalapeÃño Optimizing Compiler, and the implementation results that we have obtained thus far. To the best of our knowledge, this is the first dynamic optimizing compiler for Java that is being used in a JVM with a compile-only approach to program execution.

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This paper addresses the problem of resolving virtual method and interface calls in Java bytecode. The main focus is on a new practical technique that can be used to analyze large applications. Our fundamental design goal was to develop a technique that can be solved with only one iteration, and thus scales linearly with the size of the program, while at the same time providing more accurate results than two popular existing linear techniques, class hierarchy analysis and rapid type analysis. We present two variations of our new technique, variable-type analysis and a coarser-grain version called declared-type analysis. Both of these analyses are inexpensive, easy to implement, and our experimental results show that they scale linearly in the size of the program. We have implemented our new analyses using the Soot framework, and we report on empirical results for seven benchmarks. We have used our techniques to build accurate call graphs for complete applications (including librarie...

Relevant context inference (RCI) is a modular technique for flow- and context-sensitive data-flow analysis of statically typed object-oriented programming languages such as C ++ and Java. RCI can be used to analyze complete programs as well as incomplete programs such as libraries; this approach does not require that the entire program be memoryresident during the analysis. RCI is presented in the context of points-to analysis for a realistic subset of C ++ . The empirical evidence obtained from a prototype implementation argues the effectiveness of RCI. 1 Introduction Points-to analysis [EGH94] for statically typed objectoriented programming languages (e.g., Java, C ++ ) determines, at each program point, the objects to which a pointer may point during execution. This information is crucial to many applications, including static resolution of dynamically dispatched calls, side-effect analysis, data-flow-based testing, program slicing and aggressive compiler optimizations. The s...

The goal of points-to analysis for Java is to determine the set of objects pointed to by a reference variable or a reference object field. This information has a wide variety of client applications in optimizing compilers and software engineering tools. In this paper we present a points-to analysis for Java based on Andersen's points-to analysis for C [5]. We implement the analysis by using a constraint-based approach which employs annotated inclusion constraints. Constraint annotations allow us to model precisely and efficiently the semantics of virtual calls and the flow of values through object fields. By solving systems of annotated inclusion constraints, we have been able to perform practical and precise points-to analysis for Java.

The goal of points-to analysis for Java is to determine the set of objects pointed to by a reference variable or a reference object field. We present object sensitivity, a new form of context sensitivity for flow-insensitive points-to analysis for Java. The key idea of our approach is to analyze a method separately for each of the object names that represent runtime objects on which this method may be invoked. To ensure flexibility and practicality, we propose a parameterization framework that allows analysis designers to control the tradeo#s between cost and precision in the object-sensitive analysis.

The goal of points-to analysis for Java is to determine the set of objects pointed to by a reference variable or a reference objet field. Improving the precision of practical points-to analysis is important because points-to information has a wide variety of client applications in optimizing compilers and software engineering tools. In this paper we present object sensitivity, a new form of context sensitivity for flow-insensitive points-to analysis for Java. The key idea of our approach is to analyze a method separately for each of the objects on which this method is invoked. To ensure flexibility and practicality, we propose a parameterization framework that allows analysis designers to control the tradeoffs between cost and precision in the object-sensitive analysis.

We discuss aspects of inlining of virtual method invocations. First, we introduce a new method test to guard inlinings of such invocations, with a different set of tradeoffs from the class-equality tests proposed previously in the literature. Second, we consider the problem of inlining virtual methods directly, with no guarding test, in dynamic languages such as Self or the Java(tm) programming language, whose semantics prohibit a static identification of the complete set of modules that comprise a program. In non-dynamic languages, a whole-program analysis might prove the correctness of a direct virtual inlining. In dynamic languages, however, such analyses can be invalidated by later class loading, and must therefore be treated as assumptions whose later violation must cause recompilation. In the past, such systems have required an on-stack replacement mechanism to update currently-executing invocations of methods containing invalidated inlinings. This paper presents analyses that allow some virtual calls to be inlined directly even if class loading invalidates the inlining for future invocations. This provides the benefits of direct inlining without the need for on-stack replacement, which can be complicated and require space-consuming data structures.

Abstract. This paper presents and evaluates a set of analyses designed to reduce synchronization overhead in Java programs. Monitor-based synchronization in Java often causes significant overhead, accounting for 5-10 % of total execution time in our benchmark applications. To reduce this overhead, programmers often try to eliminate unnecessary lock operations by hand. Such manual optimizations are tedious, error-prone, and often result in poorly structured and less reusable programs. Our approach replaces manual optimizations with static analyses that automatically find and remove unnecessary synchronization from Java programs. These analyses optimize cases where a monitor is entered multiple times by a single thread, where one monitor is nested within another, and where a monitor is accessible by only one thread. A partial implementation of our analyses eliminates up to 70 % of synchronization overhead and improves running time by up to 5 % for several already hand-optimized benchmarks. Thus, our automated analyses have the potential to significantly improve the performance of Java applications while enabling programmers to design simpler and more reusable multithreaded code. 1.

A fundamental problem in software-based security is whether local security checks inserted into the code are sufficient to implement a global security property. We introduce a formalism based on a two-level linear-time temporal logic for specifying global security properties pertaining to the control-flow of the program, and illustrate its expressive power with a number of existing properties. We define a minimalistic, security-dedicated program model that only contains procedure call and run-time security checks and propose an automatic method for verifying that an implementation using local security checks satisfies a global security property. For a given formula in the temporal logic we prove that there exists a bound on the size of the states that have to be considered in order to assure the validity of the formula: this reduces the problem to finite-state model checking. Finally, we instantiate the framework to the security architecture proposed for Java (JDK 1.2).