Understanding Compiler Bugs in Real Development

Abstract

Compilers are critical in development, but compiler bugs can cause hidden and serious bugs in their compiled code. To deepen the understanding of compiler bugs, in the prior empirical studies, researchers read the bug reports and patches of compilers, and analyze their causes, locations, and patterns. Although they derive many interesting findings, their studies are limited. First, as bug reports seldom explain which projects encounter compiler bugs, it is infeasible to understand the outreaching impact. Second, before compiler bugs are fixed, programmers can bypass such bugs. The bug reports of compilers do not introduce such workarounds. Finally, the distribution of compiler bugs can be distorted, since researchers and compiler developers also file bug reports. In this paper, we propose a novel angle to analyze compiler bugs. Instead of compiler bug reports, we collect compiler bugs that are mentioned in real development. When programmers encounter compiler bugs in real development, they can leave traces in their commit messages. By searching such messages, we collected 644 unique commits whose messages explicitly mention the urls of compiler bugs. From this angle, in this paper, we conduct the first empirical study to analyze compiler bugs in the wild. We summarize our results into seven useful findings for users, compiler developers, and researchers. For example, for researchers, we find that some large workarounds of compiler bugs involve repetitive and systematic changes, which indicates a new research opportunity for code migration tools. Furthermore, we attempt to apply our findings in real development, and we obtain positive feedback.