To increase modularity, many aspect-oriented programming languages provide a mechanism based on implicit invocation: An aspect can influence runtime behavior of other modules without the need that these modules refer to the aspect. Recent studies show that a significant part of reported bugs in aspect-oriented programs are caused exactly by this implicitness. These bugs are difficult to detect, because aspect-oriented source code elements and their locations are transformed or even lost after compilation. We investigate four dedicated fault models and identify 11 tasks that a debugger should be able to perform for detecting aspect-orientation-specific faults. We show that existing debuggers are not powerful enough to support all identified tasks, because the aspect-oriented abstractions are lost after compilation.
This paper describes the design and implementation of a debugger for aspect-oriented languages using a dedicated intermediate representation preserving the abstraction level of aspect-oriented source code. This is based on a model of the more general formalism of advanced dispatching. Based on this model, we implement a user interface with functionalities supporting the identified tasks, such as visualizing pointcut evaluation and program composition. Due to the generality of our intermediate representation, our debugger can be used for a wide range of programming languages. To account for the syntactic differences among these languages, we allow language designers to customize the textual representations on the user interface.