Sealed Calls in Java Packages

摘要

Determining the potnetial targets of virtual method invocations is essential for inter-procedural optimizations of object-oriented programs. It is generally hard to determine such targets accurately. The problem is especially difficult for dynamic languages such as Java, because additional targets of virtual calls may appear at runtime. Current mechanisms that enable inter-procedural optimizations for dynamic languages, repeatedly validate the optimizations at runtime. this paper addresses this predicament by proposing a novel technique for conservative devirtualization analysis, which applies to a significant number of virutal calls in Java programs. Unlike previous work, our technique requires neither whole program analysis nor runtime information, and incurs no rutnime overhead. Our solution is very efficient to compute and is based on a newly introudce,d seemingly un-related security feature of Java file archives. On average, our analysis "seals" (safely devirtualizes) about 39