SHF: Small: Reverse Engineering Variability Implementations

软件系统中的可变性是非常普遍和重要的，它可以使系统适应用户的需求，并在不同的环境中灵活地使用系统，而不需要为每个环境从头开始开发新的系统。例如，资源受限的嵌入式系统、高性能优化和终端用户可定制的系统都利用了可变性。然而，软件系统的可变性在(A)重用和(B)开发和维护成本之间造成了基本的紧张。一方面，预先规划可变性能够实现系统重用，并承诺显著减少开发工作、成本和上市时间。另一方面，变化性需要前期投资并导致长期维护成本，因为变化性会导致具有潜在复杂交互作用的指数级配置。特别是如果以一种特别的方式引入，并且没有得到适当的管理，可变性可能会增加维护成本，达到超过预期收益的水平。这项研究开发和集成了可变性的逆向工程技术，以降低可变性的前期投资，并减少由于现有即席可变性实现的意外复杂性而导致的长期维护成本。本项目通过鼓励轻量级和增量实现机制，并为实践中常见的所有即席遗留实现提供迁移机制，来回顾可变和可重用软件的实现方式，包括条件编译(#ifdef)、分支、克隆、文本补丁、命令行参数和插件。它集成了来自不同社区的研究，包括产品线分析、静态分析、重构、关注点定位和架构恢复，以实现逆向工程可变性实现的共同目标。这种集成将允许扩展研究和实践，分析可变性并将其从corecalculi迁移到Linux内核的大小和复杂性的真实世界系统。

Variability in software systems is very common and important to tailorthe system to user needs and to use the system flexibly in differentcontexts without developing a new system from scratch for each context.For example, embedded systems with resource constraints,high-performance optimizations, and end-user customizable systems allexploit variability. However variability in software systems creates afundamental tension between (a) reuse and (b) development andmaintenance costs. On the one hand, planning variability upfront enablessystematic reuse and promises to significantly reduce developmenteffort, costs, and time to market. On the other hand, variabilityrequires an upfront investment and causes long-term maintenance costs,because variations give rise to an exponential number of configurations with potentially intricate interactions. Especially if introduced inan ad-hoc fashion and not managed appropriately, variability canincrease maintenance costs to a level that outweighs the expectedbenefits. This research develops and integrates reverse-engineeringtechniques for variability to lower upfront investments for variabilityand to reduce the costs of long-term maintenance caused by accidentalcomplexity of existing ad-hoc variability implementations.This project revisits how variable and reusable software is implementedby encouraging lightweight and incremental implementation mechanisms andproviding migration mechanisms for all ad-hoc legacy implementationscommon in practice, including conditional compilation (#ifdef),branches, clones, textual patches, command-line parameters, andplug-ins. It integrates research from different communities, includingproduct- line analysis, static analysis, refactoring, concern location,and architecture recovery toward a common goal of reverse engineeringvariability implementations . This integration will allow scalingresearch and practice of analyzing and migrating variability from corecalculi to real-world systems of the size and complexity of the Linuxkernel.