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Conservative call graph construction using dynamic CHA

Due to polymorphism, the exact types of the receiver of a virtual call site may not be known at analysis time. Class hierarchy analysis (CHA) [9] makes the conservative assumption that all subtypes of a receiver's declaring type are possible types at runtime.

CHA was originally suggested as a static analysis, where all classes and the complete class hierarchy are known at compile time. However, when adapting CHA to be a dynamic analysis one must consider that the class hierarchy can grow as classes are dynamically loaded. Thus a dynamic CHA must record all virtual call sites that have already been resolved. When a new class is loaded, it must be included in the the type set of any recorded call site whose receiver's declaring class is a super type of the newly loaded class. If the newly added type, of a call site, declares a method with the same signature as the callee, a new call edge to the method must be generated at this call site. Hirzel et. al. [15] have given a detailed description of this approach. In our study, we implemented a call graph builder using dynamic CHA to compare with our proposed profiler-based mechanism.

Feng Qian 2004-02-16