John C. Reynolds
Carnegie Mellon University

Separation Logic: A Logic for Shared Mutable Data Structures


In joint work with Peter O'Hearn and others, based on early ideas of Burstall, we have developed an extension of Hoare logic that permits reasoning about low-level imperative programs that use shared mutable data structure.

The simple imperative programming language is extended with commands (not expressions) for accessing and modifying shared structures, and for explicit allocation and deallocation of storage.  Assertions are extended by introducing a ``separating conjunction'' that asserts that its subformulas hold for disjoint parts of the heap, and a closely related "separating implication".  Coupled with the inductive definition of predicates on abstract data structures, this extension permits the concise and flexible description of structures with controlled sharing.

In this paper, we will survey the current development of this program logic, including extensions that permit unrestricted address arithmetic, dynamically allocated arrays, and recursive procedures.  We will also discuss promising future directions.

KEYWORDS: separation logic, shared data structures, mutable data structures, Hoare logic, logic of bunched implications, separating conjunction, separating implication, address arithmetic, program specification, program verification.

Principles of Programming Seminars

Friday, January 24, 2003
3:30 p.m.
Wean Hall 8220