Sip4J: Statically inferring permission-based specifications for sequential Java programs
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In mainstream programming languages such as Java, a common way to enable concurrency is to manually introduce explicit concurrency constructs such as multi-threading. Given the intricacies in creating these constructs, it is very likely for a programmer to omit important dependencies (constraints) or to create wrong or misspelled specifications that may lead to problems such as race conditions and deadlocks. With these considerations in mind, access permission-based dependencies have been investigated as an alternative approach to formally verify the correctness of multi-threaded programs and to exploit the implicit concurrency present in sequential programs. Access permissions are abstract capabilities that model read and write effects of a reference on a referenced object in the presence or absence of aliases. However, significant annotation overhead can arise from manually adding permission-based specifications in a source program, diminishing the effectiveness of existing permission-based approaches. In this paper, we present a framework, Sip4J to automatically extract implicit dependencies from sequential Java programs in the form of access permissions, by performing inter-procedural static analysis of the source code. We have integrated an existing tool Pulse to automatically verify correctness of the inferred specifications and to reason about their concurrent behaviors. Our evaluation on some widely-used benchmarks gives strong evidence of the correctness of the inferred annotations and their effectiveness in enabling concurrency in sequential programs.
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