Common Contracts

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May 8th, 2008

• Filed
  May 8th, 2008

Abstract. We adapt a variant of permission-accounting separation logic to a con- current Java-like language with fork/join. To support both concurrent reads and information hiding, we combine fractional permissions with abstract predicates. As an example, we present a separation logic contract for iterators that prevents data races and concurrent modifications. Our program logic is presented in an al- gorithmic style: we avoid structural rules for Hoare triples and formalize logical reasoning about typed heaps by natural deduction rules and a set of sound ax- ioms. We show that verified programs satisfy the following properties: data race freedom, absence of null-dereferences and partial correctness.