Speedup Automatic Program Repair Using Dynamic Software Updating: An Empirical Study

A typical generate-and-validate automatic program repair (APR) tool needs to repeatedly run the same test suite to validate each generated patch. This procedure is expensive when the number of patches is huge. Additionally, to scale to large programs, a program repair tool has to consider a small patch space in practice and thus may sacrifice the capability to find potential correct repairs. In this work, we propose to speed up automatic program repair to mitigate the above issues. One the one hand, we found that restarting processes to load patched code consumes the majority of total validation time. This problem is even severe when the program is running in a managed runtime such as Java virtual machine (JVM). On the other hand, dynamic software updating (DSU) can load and execute new code without restarting. To this end, we propose to use DSU techniques to speed up automatic program repair and present an empirical study in this paper. Within our study, DSU can bring up to 66.3 times speedup in comparison with the traditional restart approach. However, DSU may not be able to handle all patches and can also incur unknown side effects that lead to inconsistent validation results. We then further study the feasibility and consistency of applying DSU to speed up APR. Our results show that 1) less than 1% patches cannot be dynamically updated using the builtin DSU ability of JVM, and 2) DSU based validation leads to potentially harmful inconsistency in only 16 of 1,897,518 patches.