Dynamic alias protection with aliasing contracts

Abstract

Object-oriented languages allow any object to point to any other object, limited only by type. The resultant possible aliasing makes programs hard to verify and maintain. Much research has been done on alias protection schemes to restrict aliasing. However, existing schemes are either informal (design-pattern-like) or static type-like systems. The former are hard to verify, while the latter tend to be inflexible (e.g. shared ownership is problematic). We introduce aliasing contracts : a novel, dynamic alias protection scheme which is highly flexible. We present JaCon, a prototype implementation of aliasing contracts for Java, and use it to quantify their runtime performance overheads. Results show that aliasing contracts perform comparably to existing debugging tools, demonstrating practical feasibility. © Springer International Publishing 2013.