SAVER: Scalable, Precise, and Safe Memory-Error Repair

We present SAVER, a new memory-error repair technique for C programs. Memory errors such as memory leak, double-free, and use-after-free are highly prevalent and fixing them requires significant effort. Automated program repair techniques hold the promise of reducing this burden but the state-of-the-art is still unsatisfactory. In particular, no existing techniques are able to fix those errors in a scalable, precise, and safe way, all of which are required for a truly practical tool. SAVER aims to address these shortcomings. To this end, we propose a method based on a novel representation of the program called object flow graph, which summarizes the program's heap-related behavior using static analysis. We show that fixing memory errors can be formulated as a graph labeling problem over object flow graph and present an efficient algorithm. We evaluated SAVER in combination with Infer, an industrial-strength static bug-finder, and show that 74% of the reported errors can be fixed automatically for a range of open-source C programs.