Nu: Towards a Flexible and Dynamic Aspect-Oriented Intermediate Language Model
The contribution of this work is the design, implementation and evaluation of a new aspect-oriented intermediate language model that we call Nu. The primary motivation behind the design of the Nu model is to maintain the aspect-oriented design modularity in the intermediate code for the responsiveness of incremental compilers and source-level debuggers. Nu extends the object-oriented intermediate language model with two primitives: bind and remove. We demonstrate that these primitives are capable of expressing statically deployed constructs such as AspectJ's aspect, dynamic deployment construct such as CaeserJ's deploy as well as dynamic control flow constructs such as AspectJ's cflow by presenting compilation techniques from high-level languages to Nu for these constructs. Moreover, these compilation techniques also serve to show that aspect-oriented design modularity is indeed preserved in the Nu intermediate code. We also present the design and implementation of a prototype extension of the Sun Hotspot virtual machine that supports the Nu model, which serves to show that it is feasible to implement Nu in a production level virtual machine. A key concern for dynamic language models is the performance overhead of their implementation. Our performance analysis results show that method dispatch time is not degraded in our prototype implementation. Also, advice dispatch time remains fairly close to the manually inlined version.