Nu: a Dynamic Aspect-Oriented Intermediate Language Model and Virtual Machine for Flexible Runtime Adaptation

A variety of dynamic aspect-oriented language constructs are proposed in recent literature with corresponding, compelling use cases. Such constructs, as well as other existing constructs such as cflow, demonstrate the need to dynamically adapt the set of join points intercepted at a fine-grained level. The notion of morphing aspects and continuous weaving is motivated by this need. In this work, we propose an intermediate language model called Nu, that extends object-oriented intermediate language models with two finegrained deployment primitives: bind and remove. These primitives offer a higher level of abstraction as a compilation target for dynamic aspect-oriented language constructs, compared to objectoriented intermediate language models, thereby making it easier to support such constructs. We also present the design and implementation of a prototype virtual machine that supports the Nu model, which serves to show that it is feasible to support such a flexible and dynamic intermediate language model in a production level virtual machine. We demonstrate the potential utility of the intermediate language design by expressing a variety of aspect-oriented source language constructs of dynamic flavor such as CaeserJ’s deploy, historybased pointcuts, and control flow constructs such as cflow in terms of the Nu model