Automated Reasoning for Multi-step Software Product-line Configuration Problems

The increasing complexity and cost of softwareintensive systems has led developers to seek ways of reusing software components across development projects. One approach to increasing software reusability is to develop a Software Product-line (SPL), which is a software architecture that can be reconfigured and reused across projects. Rather than developing software from scratch for a new project, a new configuration of the SPL is produced. It is hard, however, to find a configuration of the SPL that meets an arbitrary requirement set and does not violate any configuration constraints in the SPL. Existing research has focused on techniques that produce a configuration of the SPL in a single step. Budgetary constraints or other restrictions, however, may require multi-step configuration processes. For example, an automotive manufacturer may want to produce a series of configurations of a car over a span of years without exceeding a yearly budget to add features. This paper provides three contributions to the study of multistep configuration for SPLs. First, we present a formal model of multi-step SPL configuration and map this model to constraint satisfaction problems (CSPs). Second, we show how solutions to these SPL configuration problems can be automatically derived with a constraint solver by mapping them to CSPs. Third, we present empirical results demonstrating that our CSP-based reasoning technique can scale to SPL models with hundreds of features and multiple configuration steps.