SHF: Small: A Practical Program Transformation Infrastructure for C in the Presence of Multiple Configurations

在过去的十年中，软件工程领域已经看到了自动化重构工具的快速和广泛采用：在程序员的指导下分析源代码的工具，并对该程序进行系统更改，以改善其内部结构而不影响其行为。在C编程语言中，这是使用中最流行的语言之一，只有有限的重构组合可用，具有有限的可扩展性和对现实世界程序的有限适用性。这项研究将解决的技术问题，使其难以建立自动重构工具（和其他程序转换工具）的C：“配置”C程序使用预处理器宏的能力，需要执行复杂的分析，在存在许多这样的配置，并需要分析和转换C当它与其他编程语言混合。解决这些问题，并产生一个工具，结合这些解决方案，将提供急需的工具改进C programmer.The研究将最终在原型重构和C程序转换工具，解决上述问题。处理多个预处理器配置将涉及解析算法和程序表示的探索：解析算法扩展了LALR（1）算法以处理预处理器指令，而程序表示在单个抽象语法树（AST）中容纳多个配置。语义信息（来自各种静态分析）将叠加在AST上;然而，这将需要扩展静态分析以处理多个预处理器配置所带来的复杂性。该工具还将允许转换混合语言C程序-特别是与Fortran或Yacc（通常与C结合的两种语言）混合的C程序。处理多种语言可以被视为多配置问题的扩展，其中一种语言的声明和不同语言的定义至少在概念上被视为不同的配置。该工具将在开源许可证下提供。

Over the last decade, the field of Software Engineering has seen a rapid and widespread adoption of automated refactoring tools: tools that analyze the source code under the direction of the programmer, and make systematic changes to that program that improve its internal structure without affecting its behavior. In the C programming language, which is one of the most popular languages in use, there is only a limited portfolio of refactorings available, with limited scalability and limited applicability to real-world programs. This research will address the technical problems that make it difficult to build automated refactoring tools (and other program transformation tools) for C: the ability to "configure" C programs using preprocessor macros, the need to perform sophisticated analyses in the presence of many such configurations, and the need to analyze and transform C when it is mixed with other programming languages. Solving these problems, and producing a tool that incorporates these solutions, will provide much needed tool improvements for C programmers.The research will culminate in a prototype refactoring and program transformation tool for C that addresses the aforementioned problems. Handling multiple preprocessor configurations will involve the exploration of both a parsing algorithm and a program representation: the parsing algorithm extends the LALR(1) algorithm to handle preprocessor directives, while the program representation accommodates multiple configurations in a single abstract syntax tree (AST). Semantic information (from various static analyses) will be superimposed on the AST; however, this will require extending the static analyses to handle the complications presented by multiple preprocessor configurations. The tool will also allow for transforming mixed-language C programs--in particular, C programs mixed with Fortran or Yacc (two languages that are commonly combined with C). Handling multiple languages may be treated as an extension of the multiple configurations problem, where declarations in one language and definitions in a different language are treated, at least conceptually, as different configurations. The tool will be available under an open source license.