org.sosy_lab.cpachecker.cpa.value.refiner.ValueAnalysisStrongestPostOperator.java Source code

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Here is the source code for org.sosy_lab.cpachecker.cpa.value.refiner.ValueAnalysisStrongestPostOperator.java

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/*
 * CPAchecker is a tool for configurable software verification.
 *  This file is part of CPAchecker.
 *
 *  Copyright (C) 2007-2015  Dirk Beyer
 *  All rights reserved.
 *
 *  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.
 *
 *
 *  CPAchecker web page:
 *    http://cpachecker.sosy-lab.org
 */
package org.sosy_lab.cpachecker.cpa.value.refiner;

import java.util.Collection;
import java.util.Collections;
import java.util.Deque;
import java.util.Set;

import org.sosy_lab.common.configuration.Configuration;
import org.sosy_lab.common.configuration.InvalidConfigurationException;
import org.sosy_lab.common.log.LogManager;
import org.sosy_lab.cpachecker.cfa.CFA;
import org.sosy_lab.cpachecker.cfa.model.CFAEdge;
import org.sosy_lab.cpachecker.cfa.model.CFANode;
import org.sosy_lab.cpachecker.cfa.model.FunctionExitNode;
import org.sosy_lab.cpachecker.core.defaults.VariableTrackingPrecision;
import org.sosy_lab.cpachecker.core.interfaces.Precision;
import org.sosy_lab.cpachecker.cpa.arg.ARGPath;
import org.sosy_lab.cpachecker.cpa.conditions.path.AssignmentsInPathCondition.UniqueAssignmentsInPathConditionState;
import org.sosy_lab.cpachecker.cpa.value.ValueAnalysisState;
import org.sosy_lab.cpachecker.cpa.value.ValueAnalysisTransferRelation;
import org.sosy_lab.cpachecker.exceptions.CPAException;
import org.sosy_lab.cpachecker.util.AbstractStates;
import org.sosy_lab.cpachecker.util.refinement.StrongestPostOperator;
import org.sosy_lab.cpachecker.util.states.MemoryLocation;

import com.google.common.base.Optional;
import com.google.common.collect.Iterables;

/**
 * Strongest post-operator using {@link ValueAnalysisTransferRelation}.
 */
public class ValueAnalysisStrongestPostOperator implements StrongestPostOperator<ValueAnalysisState> {

    private final ValueAnalysisTransferRelation transfer;

    public ValueAnalysisStrongestPostOperator(final LogManager pLogger, final Configuration pConfig, final CFA pCfa)
            throws InvalidConfigurationException {

        transfer = new ValueAnalysisTransferRelation(pConfig, pLogger, pCfa);
    }

    @Override
    public Optional<ValueAnalysisState> getStrongestPost(final ValueAnalysisState pOrigin,
            final Precision pPrecision, final CFAEdge pOperation) throws CPAException {

        final Collection<ValueAnalysisState> successors = transfer.getAbstractSuccessorsForEdge(pOrigin, pPrecision,
                pOperation);

        if (successors.isEmpty()) {
            return Optional.absent();

        } else {
            return Optional.of(Iterables.getOnlyElement(successors));
        }
    }

    @Override
    public ValueAnalysisState handleFunctionCall(ValueAnalysisState state, CFAEdge edge,
            Deque<ValueAnalysisState> callstack) {
        callstack.addLast(state);
        return state;
    }

    @Override
    public ValueAnalysisState handleFunctionReturn(ValueAnalysisState next, CFAEdge edge,
            Deque<ValueAnalysisState> callstack) {

        final ValueAnalysisState callState = callstack.removeLast();
        return next.rebuildStateAfterFunctionCall(callState, (FunctionExitNode) edge.getPredecessor());
    }

    @Override
    public ValueAnalysisState performAbstraction(final ValueAnalysisState pNext, final CFANode pCurrNode,
            final ARGPath pErrorPath, final Precision pPrecision) {

        assert pPrecision instanceof VariableTrackingPrecision;

        VariableTrackingPrecision precision = (VariableTrackingPrecision) pPrecision;

        final boolean performAbstraction = precision.allowsAbstraction();
        final Collection<MemoryLocation> exceedingMemoryLocations = obtainExceedingMemoryLocations(pErrorPath);

        if (performAbstraction) {
            for (MemoryLocation memoryLocation : pNext.getTrackedMemoryLocations()) {
                if (!precision.isTracking(memoryLocation, pNext.getTypeForMemoryLocation(memoryLocation),
                        pCurrNode)) {
                    pNext.forget(memoryLocation);
                }
            }
        }

        for (MemoryLocation exceedingMemoryLocation : exceedingMemoryLocations) {
            pNext.forget(exceedingMemoryLocation);
        }

        return pNext;
    }

    protected Set<MemoryLocation> obtainExceedingMemoryLocations(final ARGPath pPath) {
        UniqueAssignmentsInPathConditionState assignments = AbstractStates.extractStateByType(pPath.getLastState(),
                UniqueAssignmentsInPathConditionState.class);

        if (assignments == null) {
            return Collections.emptySet();
        }

        return assignments.getMemoryLocationsExceedingThreshold();
    }
}