CCF: Small: A Programming Environment for High Performance Computing Based on Practical Program Transformation

成功的软件系统会继续发生变化。大多数程序员从事的项目都不是他们开始的，而且大多数公司花在维护旧系统上的钱比花在构建新系统上的钱更多。这项研究的目标是通过开发更好的软件工具和研究程序员如何更改软件来使程序更容易更改。该项目正在扩展Photran，一个FORTRAN的开源编程环境，以便它更好地支持FORTRAN程序员改变他们的软件使他们在下一代超级计算机上运行的方式。新版本的Photran将有可能使移植高性能软件的成本大大降低，这些想法有可能从总体上降低软件开发的成本。新系统将记录程序员所做的每一项更改，并将在高级别上表示这些更改，即不仅作为文本更改，而且作为更有意义的更改单元，如重构或优化。它将允许程序员在事后修改这些更改，从而可以更改程序的可移植版本，然后重播手工制作的优化。程序员可以将程序移植到新的体系结构中，方法是从可移植版本开始，然后选择对类似机器有用的优化，或由自动调谐器发现的优化，或根据需要发明的优化。他们将能够将程序视为程序转换的序列，并通过重用来自其他程序的子序列来生成新程序。因此，一系列更改将与一组模块一样有效地表示程序

Successful software systems continue to change. Most programmers work on projects that they did not start, and most companies spend more on maintaining old systems than on building new ones. This goal of this research is to make programs easier to change by developing better software tools and by studying how programmers change software. The project is extending Photran, an open-source programming environment for FORTRAN, so that it better supports the way FORTRAN programmers change their software to make them run on next-generation supercomputers. The new version of Photran will have the potential to make it much less expensive to port high-performance software, and the ideas have the potential to reduce the cost of software development in general.The new system will record each change that a programmer makes and will represent these changes at a high-level, i.e. not just as textual changes, but as more meaningful units of changes, such as refactoring or optimizations. It will let programmers modify these changes after the fact, making it possible to change the portable version of a program and then replay the hand-crafted optimizations. Programmers can port a program to a new architecture by starting with a portable version and then choosing optimizations that were useful for similar machines, or that were discovered by an auto-tuner, or that were invented as needed. They will be able to think of a program as a sequence of program transformations, and to generate a new program by reusing sub-sequences from other programs. Thus, a sequence of changes will be just as valid a representation of a program as a set of modules