Challenges in Decomposing Encodings of Verification Problems
This addresses a scalability problem for program verifiers, but it is incremental as it builds on existing decomposition techniques.
The paper tackles the scalability issue of program verification by decomposing logical formulas for termination analysis, which significantly increases efficiency but can deteriorate precision due to added abstractions.
Modern program verifiers use logic-based encodings of the verification problem that are discharged by a back end reasoning engine. However, instances of such encodings for large programs can quickly overwhelm these back end solvers. Hence, we need techniques to make the solving process scale to large systems, such as partitioning (divide-and-conquer) and abstraction. In recent work, we showed how decomposing the formula encoding of a termination analysis can significantly increase efficiency. The analysis generates a sequence of logical formulas with existentially quantified predicates that are solved by a synthesis-based program analysis engine. However, decomposition introduces abstractions in addition to those required for finding the unknown predicates in the formula, and can hence deteriorate precision. We discuss the challenges associated with such decompositions and their interdependencies with the solving process.