Soft contract verification for higher-order stateful programs
| Autor: | Thomas Gilray, Phuc C. Nguyen, Sam Tobin-Hochstadt, David Van Horn |
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| Rok vydání: | 2017 |
| Předmět: |
FOS: Computer and information sciences
Soundness Computer Science - Programming Languages Correctness Computer science Programming language Overhead (engineering) 020207 software engineering Context (language use) 02 engineering and technology Symbolic execution computer.software_genre Stateful firewall 020204 information systems Racket 0202 electrical engineering electronic engineering information engineering State (computer science) Safety Risk Reliability and Quality computer Software Programming Languages (cs.PL) computer.programming_language |
| Zdroj: | David Van Horn |
| ISSN: | 2475-1421 |
| DOI: | 10.1145/3158139 |
| Popis: | Software contracts allow programmers to state rich program properties using the full expressive power of an object language. However, since they are enforced at runtime, monitoring contracts imposes significant overhead and delays error discovery. So contract verification aims to guarantee all or most of these properties ahead of time, enabling valuable optimizations and yielding a more general assurance of correctness. Existing methods for static contract verification satisfy the needs of more restricted target languages, but fail to address the challenges unique to those conjoining untyped, dynamic programming, higher-order functions, modularity, and statefulness. Our approach tackles all these features at once, in the context of the full Racket system---a mature environment for stateful, higher-order, multi-paradigm programming with or without types. Evaluating our method using a set of both pure and stateful benchmarks, we are able to verify 99.94% of checks statically (all but 28 of 49, 861). Stateful, higher-order functions pose significant challenges for static contract verification in particular. In the presence of these features, a modular analysis must permit code from the current module to escape permanently to an opaque context (unspecified code from outside the current module) that may be stateful and therefore store a reference to the escaped closure. Also, contracts themselves, being predicates wri en in unrestricted Racket, may exhibit stateful behavior; a sound approach must be robust to contracts which are arbitrarily expressive and interwoven with the code they monitor. In this paper, we present and evaluate our solution based on higher-order symbolic execution, explain the techniques we used to address such thorny issues, formalize a notion of behavioral approximation, and use it to provide a mechanized proof of soundness. Comment: ACM SIGPLAN Symposium on Principles of Programming Language (POPL) |
| Databáze: | OpenAIRE |
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