Program Behavior Model Based on Event Grammar and its Application for Debugging Automation

The notion of event constitutes the basis of the target program behavior model. This model, called H-space (History-space), is formally defined through a set of axioms (event grammar) for two basic relations, which may hold between two arbitrary events: the events may be sequentially ordered or one of them might be included in another composite event. Target program execution history is represented as a set of nested events. A general paradigm of "computation over execution history" is suggested in this paper as a basis for debugging automation. A language to describe computations over execution histories of target programs provides means for assertion checking, debugging queries, profiles, and performance measurement. Event patterns and aggregate operations over event traces, can be used in order to describe typical bugs and debugging rules. The knowledge about typical bugs and debugging rules can be formalized in libraries of assertions and debugging rules and can be used for run-time detection of bugs and bug localization. Examples of assertions and debugging rules are presented and prototype implementation issues are briefly discussed.