An Axiomatic Specification for Sequential Memory Models

Formalizations of concurrent memory models often represent memory behavior in terms of sequences of operations, where operations are either reads, writes, or synchronizations. More concrete models of (sequential) memory behavior may include allocation and free operations, but also include details of memory layout or data representation. We present an abstract specification for sequential memory models with allocation and free operations, in the form of a set of axioms that provide enough information to reason about memory without overly constraining the behavior of implementations. We characterize a set of “well-behaved” programs that behave uniformly on all instances of the specification. We show that the specification is both feasible—the CompCert memory model implements it—and usable—we can use the axioms to prove the correctness of an optimization that changes the memory behavior of programs in an LLVM-like language.