Previous | 
Home
Section: New Software and Platforms
Prequel
Keywords: Code quality - Evolution - Infrastructure software
Functional Description
The commit history of a large, actively developed code base such as the Linux kernel is a gold mine of information on how evolutions should be made, how bugs should be fixed, etc. Nevertheless, the high volume of commits available and the rudimentary filtering tools provided imply that it is often necessary to wade through a lot of irrelevant information before finding example commits that can help with a specific software development problem. To address this issue, we have developed Prequel (Patch Query Language) [20]. Prequel builds on the semantic patch lamguage SmPL developed for Coccinelle, which is now well known to the Linux kernel developer community, to allow developers to scan the changes in a source code development history, taking into account not only the specific changes made, but also the context in which these changes occur. As the history of a code base under active development quickly becomes large, with the Linux kernel incorporating around 13,000 commits on each 2-3 month release cycle, a particular goal in the development of Prequel has been to provide reasonable performance. Currently, most queries in our experiments complete in under minute when running on a single core on a standard laptop. So far, we have applied Prequel to the problem of understanding how to eliminate uses of deprecated functions [20], and are investigating how it may be useful in a systematic driver porting methodology.
Prequel is publicly available under GPLv2. The development of Prequel is supported by OSADL, and Julia Lawall presented Prequel at the 2016 OSADL networking day (https://www.osadl.org/OSADL-Networking-Day-2016.networking-day-2016.0.html).