A software product line (SPL) encodes a potentially large variety of software products as variants of some common code base. Up until now, re-using traditional static analyses for SPLs was virtually intractable, as it required programmers to generate and analyze all products individually. In this work, however, we show how an important class of existing inter-procedural static analyses can be transparently lifted to SPLs. Without requiring programmers to change a single line of code, our approach SPLLIFT automatically converts any analysis formulated for traditional programs within the popular IFDS framework for inter-procedural, finite, distributive, subset problems to an SPL-aware analysis formulated in the IDE framework, a well-known extension to IFDS. Using a full implementation based on Heros, Soot, CIDE and JavaBDD, we show that with SPLLIFT one can reuse IFDS-based analyses without changing a single line of code. Through experiments using three static analyses applied to four Java-based product lines, we were able to show that our approach produces correct results and outperforms the traditional approach by several orders of magnitude.

During Software Product Line (SPL) maintenance tasks, Virtual Separation of Concerns (VSoC) allows the programmer to focus on one feature and hide the others. However, since features depend on each other through variables and control-flow, feature modularization is compromised since the maintenance of one feature may break another. In this context, emergent interfaces can capture dependencies between the feature we are maintaining and the others, making developers aware of dependencies. To better understand the impact of code level feature dependencies during SPL maintenance, we have investigated the following two questions: how often methods with preprocessor directives contain feature dependencies? How feature dependencies impact maintenance effort when using VSoC and emergent interfaces? Answering the former is important for assessing how often we may face feature dependency problems. Answering the latter is important to better understand to what extent emergent interfaces complement VSoC during maintenance tasks. To answer them, we analyze 43 SPLs of different domains, size, and languages. The data we collect from them complement previous work on preprocessor usage. They reveal that the feature dependencies we consider in this paper are reasonably common in practice; and that emergent interfaces can reduce maintenance effort during the SPL maintenance tasks we regard here.