Publication Details
Solving String Constraints with Lengths by Stabilization
Chocholatý David, Bc. (FIT BUT)
Havlena Vojtěch, Ing., Ph.D. (DITS FIT BUT)
Holík Lukáš, doc. Mgr., Ph.D. (DITS FIT BUT)
Lengál Ondřej, Ing., Ph.D. (DITS FIT BUT)
Síč Juraj, Mgr. (DITS FIT BUT)
string constraints
SMT solver
stabilization
satisfiability
We present a new algorithm for solving string constraints. The algorithm builds upon a recent method for solving word equations and regular constraints that interprets string variables as languages rather than strings and, consequently, mitigates the combinatorial explosion that plagues other approaches. We extend the approach to handle linear integer arithmetic length constraints by combination with a known principle of equation alignment and splitting, and by extension to other common types of string constraints, yielding a fully-fledged string solver. The ability of the framework to handle unrestricted disequalities even extends one of the largest decidable classes of string constraints, the chain-free fragment. We integrate our algorithm into a DPLL-based SMT solver. The performance of our implementation is competitive and even significantly better than state-of-the-art string solvers on several established benchmarks obtained from applications in verification of string programs.
@ARTICLE{FITPUB13093,
author = "Yu-Fang Chen and David Chocholat\'{y} and Vojt\v{e}ch Havlena and Luk\'{a}\v{s} Hol\'{i}k and Ond\v{r}ej Leng\'{a}l and Juraj S\'{i}\v{c}",
title = "Solving String Constraints with Lengths by Stabilization",
pages = "2112--2141",
journal = "Proceedings of the ACM on Programming Languages",
volume = 7,
number = 10,
year = 2023,
ISSN = "2475-1421",
doi = "10.1145/3622872",
language = "english",
url = "https://www.fit.vut.cz/research/publication/13093"
}