hu.bme.mit.theta.xta.analysis.lazy.FwItpExplStrategy Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of theta-xta-analysis Show documentation
Xta Analysis subproject in the Theta model checking framework
The newest version!
/*
 *  Copyright 2024 Budapest University of Technology and Economics
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package hu.bme.mit.theta.xta.analysis.lazy;

import java.util.Collection;

import hu.bme.mit.theta.analysis.State;
import hu.bme.mit.theta.analysis.algorithm.arg.ArgEdge;
import hu.bme.mit.theta.analysis.algorithm.arg.ArgNode;
import hu.bme.mit.theta.analysis.expl.ExplState;
import hu.bme.mit.theta.core.model.Valuation;
import hu.bme.mit.theta.core.type.Expr;
import hu.bme.mit.theta.core.type.booltype.BoolLitExpr;
import hu.bme.mit.theta.core.type.booltype.BoolType;
import hu.bme.mit.theta.core.utils.ExprUtils;
import hu.bme.mit.theta.xta.XtaSystem;
import hu.bme.mit.theta.xta.analysis.XtaAction;
import hu.bme.mit.theta.xta.analysis.expl.XtaExplUtils;
import hu.bme.mit.theta.xta.analysis.expl.itp.ItpExplState;
import hu.bme.mit.theta.xta.analysis.lazy.LazyXtaStatistics.Builder;

final class FwItpExplStrategy extends ItpExplStrategy {

    public FwItpExplStrategy(final XtaSystem system, final Lens lens) {
        super(system, lens);
    }

    @Override
    protected Valuation blockExpl(final ArgNode node, final Expr expr,
                                  final Collection> uncoveredNodes, final Builder stats) {
        final ExplState abstrState = getLens().get(node.getState()).getAbstrState();

        final Expr simplifiedExpr = ExprUtils.simplify(expr, abstrState);
        if (simplifiedExpr instanceof BoolLitExpr) {
            assert !((BoolLitExpr) simplifiedExpr).getValue();
            return abstrState;
        }

        stats.refineExpl();
        if (node.getInEdge().isPresent()) {
            final ArgEdge inEdge = node.getInEdge().get();
            final XtaAction action = inEdge.getAction();
            final ArgNode parent = inEdge.getSource();

            final Expr B_pre = XtaExplUtils.pre(expr, action);
            final Valuation A_pre = blockExpl(parent, B_pre, uncoveredNodes, stats);

            final Expr B = expr;
            final Valuation A = XtaExplUtils.post(A_pre, action);

            final Valuation interpolant = XtaExplUtils.interpolate(A, B);

            strengthen(node, interpolant);
            maintainCoverage(node, interpolant, uncoveredNodes);

            return interpolant;
        } else {
            final ExplState concrState = getLens().get(node.getState()).getConcrState();

            final Valuation interpolant = XtaExplUtils.interpolate(concrState, expr);

            strengthen(node, interpolant);
            maintainCoverage(node, interpolant, uncoveredNodes);

            return interpolant;
        }
    }

}