Reasoning About Lock Placements

Abstract. A lock placement describes, for each heap location, which lock guards the location, and under what circumstances. We formalize methods for reasoning about lock placements, making precise the interacting obligations between the program, the organization of the heap, and the placement of locks. Our methods capture realistic and subtle situations, such as the placement and correct use of speculative locks and lock assignments that change dynamically with updates to the heap. We present results for flat heaps with no structure, tree-structured heaps and a language of DAG-shaped heaps with bounded in-degree

Concurrent data representation synthesis

We describe an approach for synthesizing data representations for concurrent programs. Our compiler takes as input a program written using concurrent relations and synthesizes a representation of the relations as sets of cooperating data structures as well as the placement and acquisition of locks to synchronize concurrent access to those data structures. The resulting code is correct by construction: individual relational operations are implemented correctly and the aggregate set of operations is serializable and deadlock free. The relational specification also permits a high-level optimizer to choose the best performing of many possible legal data representations and locking strategies, which we demonstrate with an experiment autotuning a graph benchmark