Aspect oriented programming has been proposed as a way to improve modularity of software systems by allowing encapsulation of cross-cutting concerns. To do so, aspects specify where new functionality should apply using pointcuts. Unfortunately expressions written using todays mainstream pointcut languages are fragile, as non-local changes may easily change pointcut semantics. This is a major obstacle for evolution of aspect oriented software. In this paper we introduce a pointcut delta analysis to lighten these problems. 1 Motivation Aspect-oriented programming (AOP) as first introduced in [7] is a programming technique extending traditional programming techniques to improve software modularity. Its basic idea is to encapsulate so called cross-cutting concerns not properly modularizable using traditional programming techniques in a new kind of module called aspect. Aspects provide two constructs to specify new behavior and where it should apply: advice and pointcuts. Advice is a meth...