Detecting Deadlock in Programs with Data-Centric Synchronization

Previously, we developed a data-centric approach to concurrency control in which programmers specify synchronization constraints declaratively, by grouping shared locations into atomic sets. We implemented our ideas in a Java extension called AJ, using Java locks to implement synchronization. We proved that atomicity violations are prevented by construction, and demonstrated that realistic Java programs can be refactored into AJ without significant loss of performance. This paper presents an algorithm for detecting possible deadlock in AJ programs by ordering the locks associated with atomic sets. In our approach, a type-based static analysis is extended to handle recursive data structures by considering programmer-supplied, compiler-verified lock ordering annotations. In an evaluation of the algorithm, all 10 AJ programs under consideration were shown to be deadlock-free. One program needed 4 ordering annotations and 2 others required minor refactorings. For the remaining 7 programs, no programmer intervention of any kind was required.