Eager SAT-based solver for a quantifier-free theory of strings and bit vectors

Abstract

Techniques are described for providing a SAT-based solver for a quantifier-free theory of strings and bit vectors. The solver can be used by an automated reasoning service of a cloud provider network to analyze policies and the consequences of policies. The solver reduces an input formula to a Boolean satisfiability problem by encoding the input formula into an equisatisfiable propositional formula, where the satisfiability of the equisatisfiable propositional formula is determined by a SAT solver. Rather than using a traditional DPLL(T) style algorithm, the solver described herein bounds the length of variables in an input formula and reduces the problem to a single formula, which can then be solved using incremental SAT solving. The solver can be used independently or as part of a portfolio of solvers used to determine the satisfiability or unsatisfiability of certain formula corresponding, e.g., to questions about users' policies within a cloud provider network.