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//===- Solver.h -------------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines an interface for a SAT solver that can be used by
// dataflow analyses.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_SOLVER_H
#define LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_SOLVER_H
#include "clang/Analysis/FlowSensitive/Formula.h"
#include "clang/Basic/LLVM.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include <optional>
#include <vector>
namespace clang {
namespace dataflow {
/// An interface for a SAT solver that can be used by dataflow analyses.
class Solver {
public:
struct Result {
enum class Status {
/// Indicates that there exists a satisfying assignment for a boolean
/// formula.
Satisfiable,
/// Indicates that there is no satisfying assignment for a boolean
/// formula.
Unsatisfiable,
/// Indicates that the solver gave up trying to find a satisfying
/// assignment for a boolean formula.
TimedOut,
};
/// A boolean value is set to true or false in a truth assignment.
enum class Assignment : uint8_t { AssignedFalse = 0, AssignedTrue = 1 };
/// Constructs a result indicating that the queried boolean formula is
/// satisfiable. The result will hold a solution found by the solver.
static Result Satisfiable(llvm::DenseMap<Atom, Assignment> Solution) {
return Result(Status::Satisfiable, std::move(Solution));
}
/// Constructs a result indicating that the queried boolean formula is
/// unsatisfiable.
static Result Unsatisfiable() { return Result(Status::Unsatisfiable, {}); }
/// Constructs a result indicating that satisfiability checking on the
/// queried boolean formula was not completed.
static Result TimedOut() { return Result(Status::TimedOut, {}); }
/// Returns the status of satisfiability checking on the queried boolean
/// formula.
Status getStatus() const { return SATCheckStatus; }
/// Returns a truth assignment to boolean values that satisfies the queried
/// boolean formula if available. Otherwise, an empty optional is returned.
std::optional<llvm::DenseMap<Atom, Assignment>> getSolution() const {
return Solution;
}
private:
Result(Status SATCheckStatus,
std::optional<llvm::DenseMap<Atom, Assignment>> Solution)
: SATCheckStatus(SATCheckStatus), Solution(std::move(Solution)) {}
Status SATCheckStatus;
std::optional<llvm::DenseMap<Atom, Assignment>> Solution;
};
virtual ~Solver() = default;
/// Checks if the conjunction of `Vals` is satisfiable and returns the
/// corresponding result.
///
/// Requirements:
///
/// All elements in `Vals` must not be null.
virtual Result solve(llvm::ArrayRef<const Formula *> Vals) = 0;
// Did the solver reach its resource limit?
virtual bool reachedLimit() const = 0;
};
llvm::raw_ostream &operator<<(llvm::raw_ostream &, const Solver::Result &);
llvm::raw_ostream &operator<<(llvm::raw_ostream &, Solver::Result::Assignment);
} // namespace dataflow
} // namespace clang
#endif // LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_SOLVER_H
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