6024e5c395
clang 20.0.0 (based on r547379) from build 12806354. Bug: http://b/379133546 Test: N/A Change-Id: I2eb8938af55d809de674be63cb30cf27e801862b Upstream-Commit: ad834e67b1105d15ef907f6255d4c96e8e733f57
59 lines
2.4 KiB
C++
59 lines
2.4 KiB
C++
//===- WatchedLiteralsSolver.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 a SAT solver implementation that can be used by dataflow
|
|
// analyses.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_WATCHEDLITERALSSOLVER_H
|
|
#define LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_WATCHEDLITERALSSOLVER_H
|
|
|
|
#include "clang/Analysis/FlowSensitive/Formula.h"
|
|
#include "clang/Analysis/FlowSensitive/Solver.h"
|
|
#include "llvm/ADT/ArrayRef.h"
|
|
|
|
namespace clang {
|
|
namespace dataflow {
|
|
|
|
/// A SAT solver that is an implementation of Algorithm D from Knuth's The Art
|
|
/// of Computer Programming Volume 4: Satisfiability, Fascicle 6. It is based on
|
|
/// the Davis-Putnam-Logemann-Loveland (DPLL) algorithm [1], keeps references to
|
|
/// a single "watched" literal per clause, and uses a set of "active" variables
|
|
/// for unit propagation.
|
|
//
|
|
// [1] https://en.wikipedia.org/wiki/DPLL_algorithm
|
|
class WatchedLiteralsSolver : public Solver {
|
|
// Count of the iterations of the main loop of the solver. This spans *all*
|
|
// calls to the underlying solver across the life of this object. It is
|
|
// reduced with every (non-trivial) call to the solver.
|
|
//
|
|
// We give control over the abstract count of iterations instead of concrete
|
|
// measurements like CPU cycles or time to ensure deterministic results.
|
|
std::int64_t MaxIterations = std::numeric_limits<std::int64_t>::max();
|
|
|
|
public:
|
|
WatchedLiteralsSolver() = default;
|
|
|
|
// `Work` specifies a computational limit on the solver. Units of "work"
|
|
// roughly correspond to attempts to assign a value to a single
|
|
// variable. Since the algorithm is exponential in the number of variables,
|
|
// this is the most direct (abstract) unit to target.
|
|
explicit WatchedLiteralsSolver(std::int64_t WorkLimit)
|
|
: MaxIterations(WorkLimit) {}
|
|
|
|
Result solve(llvm::ArrayRef<const Formula *> Vals) override;
|
|
|
|
bool reachedLimit() const override { return MaxIterations == 0; }
|
|
};
|
|
|
|
} // namespace dataflow
|
|
} // namespace clang
|
|
|
|
#endif // LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_WATCHEDLITERALSSOLVER_H
|