Supporting dynamic aspect-oriented features

TL;DR: The Nu model provides a higher level of abstraction compared to traditional object-oriented ILs, making it easier to efficiently support dynamic AO features and an improved compilation target for dynamic deployment features, which makes it harder to support such features with corresponding software engineering benefits.

Abstract: Dynamic aspect-oriented (AO) features have important software engineering benefits such as allowing unanticipated software evolution and maintenance. It is thus important to efficiently support these features in language implementations. Current implementations incur unnecessary design-time and runtime overhead due to the lack of support in underlying intermediate language (IL) models. To address this problem, we present a flexible and dynamic IL model that we call Nu. The Nu model provides a higher level of abstraction compared to traditional object-oriented ILs, making it easier to efficiently support dynamic AO features. We demonstrate these benefits by providing an industrial-strength VM implementation for Nu, by showing translation strategies from dynamic source-level constructs to Nu and by analyzing the performance of the resulting IL code. Nu's VM extends the Sun Hotspot VM interpreter and uses a novel caching mechanism to significantly reduce the amortized costs of join point dispatch. Our evaluation using standard benchmarks shows that the overhead of supporting a dynamic deployment model can be reduced to as little as ˜1.5p. Nu provides an improved compilation target for dynamic deployment features, which makes it easier to support such features with corresponding software engineering benefits in software evolution and maintenance and in runtime verification.