Static analysis for enforcing intra-thread consistent locks in the migration of a legacy system

Often, legacy data management systems provide no native support to transactions. Programmers protect data from concurrent access by adopting commonly agreed patterns, relying on low level concurrency primitives, such as semaphores. In such cases, consistent data access is granted only if all code components are compliant with the adopted mutual exclusion patterns. When migrating legacy systems to modern data management systems, the ad hoc mechanisms for data protection must be replaced with modern constructs for transaction management. In such cases, a literal translation may expose problems and bugs, which were originally masked by the specific implementation and patterns in use. In this paper, we propose a static flow analysis that determines the existence of potentially incompatible locks within the same thread, which require specific code re-engineering before migrating to a modern data management system. We report the results obtained on a concrete instance of this problem.