PART_PW: From Partial Analysis Results to a Proof Witness

Today, verification tools do not only output yes or no, but also provide correctness arguments or counterexamples. While counterexamples help to fix bugs, correctness arguments are used to increase the trust in program correctness, e.g., in Proof-Carrying Code (PCC). Correctness arguments are well-studied for single analyses, but not when a set of analyses together verifies a program, each of the analyses checking only a particular part. Such a set of partial, complementary analyses is often used when a single analysis would fail or is inefficient on some program parts.We propose PART_PW, a technique which allows us to automatically construct a proof witness (correctness argument) from the analysis results obtained by a set of partial, complementary analyses. The constructed proof witnesses are proven to be valid correctness arguments and in our experiments we use them seamlessly and efficiently in existing PCC approaches.