Automatic generation of precise and useful commutativity conditions

Kshitij Bansal, Eric Koskinen, Omer Tripp

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

11 Scopus citations

Abstract

Reasoning about commutativity between data-structure operations is an important problem with applications including parallelizing compilers, optimistic parallelization and, more recently, Ethereum smart contracts. There have been research results on automatic generation of commutativity conditions, yet we are unaware of any fully automated technique to generate conditions that are both sound and effective. We have designed such a technique, driven by an algorithm that iteratively refines a conservative approximation of the commutativity (and non-commutativity) condition for a pair of methods into an increasingly precise version. The algorithm terminates if/when the entire state space has been considered, and can be aborted at any time to obtain a partial yet sound commutativity condition. We have generalized our work to left-/right-movers [27] and proved relative completeness. We describe aspects of our technique that lead to useful commutativity conditions, including how predicates are selected during refinement and heuristics that impact the output shape of the condition. We have implemented our technique in a prototype open-source tool Servois. Our algorithm produces quantifier-free queries that are dispatched to a back-end SMT solver. We evaluate Servois through two case studies: (i) We synthesize commutativity conditions for a range of data structures including Set, HashTable, Accumulator, Counter, and Stack. (ii) We consider an Ethereum smart contract called BlockKing, and show that Servois can detect serious concurrency-related vulnerabilities and guide developers to construct robust and efficient implementations.

Original languageEnglish
Title of host publicationTools and Algorithms for the Construction and Analysis of Systems - 24th International Conference, TACAS 2018, Held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2018, Proceedings
EditorsDirk Beyer, Marieke Huisman
Pages115-132
Number of pages18
DOIs
StatePublished - 2018
Event24th International Conference on Tools and Algorithms for the Construction and Analysis of Systems, TACAS 2018 Held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2018 - Thessaloniki, Greece
Duration: 14 Apr 201820 Apr 2018

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume10805 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference24th International Conference on Tools and Algorithms for the Construction and Analysis of Systems, TACAS 2018 Held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2018
Country/TerritoryGreece
CityThessaloniki
Period14/04/1820/04/18

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