private Collection<Pair<List<AbstractState>, List<ARGState>>> computeCartesianProduct(
final List<List<ARGState>> pSuccessorsForEdge,
final Map<String, Integer> pStateToPos,
final List<AbstractState> pInitialStates)
throws InterruptedException, CPAException {
// compute number of successors
int count = 0;
for (List<ARGState> successor : pSuccessorsForEdge) {
if (successor.size() > 0) {
count = count == 0 ? successor.size() : count * successor.size();
}
}
// no successor in every of the ARGs
if (count == 0) {
return Collections.emptySet();
}
Collection<Pair<List<AbstractState>, List<ARGState>>> result = new ArrayList<>(count);
// compute cartesian product
int[] indices = new int[pSuccessorsForEdge.size()];
int nextIndex = 0;
boolean restart;
int lastSize = pSuccessorsForEdge.get(pSuccessorsForEdge.size() - 1).size();
if (lastSize == 0) {
lastSize = 1;
}
while (indices[indices.length - 1] < lastSize) {
shutdown.shutdownIfNecessary();
final List<ARGState> argSuccessors = new ArrayList<>(pSuccessorsForEdge.size());
// collect ARG successors
for (int index = 0; index < indices.length; index++) {
if (pSuccessorsForEdge.get(index).size() > 0) {
argSuccessors.add(
getUncoveredSuccessor(pSuccessorsForEdge.get(index).get(indices[index])));
}
}
// combine ARG states to get one cartesian product element, assume top state if no explicit
// state information available
result.add(
Pair.of(combineARGStates(argSuccessors, pStateToPos, pInitialStates), argSuccessors));
// compute indices for elements of next cartesian element
indices[nextIndex]++;
restart = false;
while (indices[nextIndex] >= pSuccessorsForEdge.get(nextIndex).size()
&& nextIndex < indices.length - 1) {
nextIndex++;
indices[nextIndex]++;
restart = true;
}
while (restart && nextIndex > 0) {
indices[--nextIndex] = 0;
}
}
return result;
}
private Pair<Map<String, Integer>, List<AbstractState>>
identifyCompositeStateTypesAndTheirInitialInstances(Collection<ARGState> rootNodes)
throws InterruptedException, CPAException {
logger.log(Level.FINE, "Derive composite state structure of combined ARG");
List<AbstractState> initialState = new ArrayList<>();
Map<String, Integer> stateToPos = new HashMap<>();
List<String> automataStateNames = new ArrayList<>();
String name;
int nextId = 0;
Iterable<AbstractState> wrapped;
logger.log(Level.FINE, "Add non-automaton states");
for (ARGState root : rootNodes) {
shutdown.shutdownIfNecessary();
wrapped = getWrappedStates(root);
for (AbstractState innerWrapped : wrapped) {
shutdown.shutdownIfNecessary();
if (innerWrapped instanceof AssumptionStorageState) {
continue;
}
name = getName(innerWrapped);
if (stateToPos.containsKey(name)) {
if (!initialState.get(stateToPos.get(name)).equals(innerWrapped)) {
logger.log(
Level.WARNING,
"Abstract state ",
innerWrapped.getClass(),
" is used by multiple configurations, but cannot check that always start in the same initial state as it is assumed");
}
} else {
assert (initialState.size() == nextId);
if (innerWrapped instanceof AutomatonState) {
automataStateNames.add(name);
} else {
stateToPos.put(name, nextId);
initialState.add(innerWrapped);
nextId++;
}
}
}
}
logger.log(Level.FINE, "Add automaton states related to specification");
Collections.sort(automataStateNames);
int numRootStates = rootNodes.size();
Set<String> commonAutomataStates = new TreeSet<>();
for (int i = 1, j = 0; i < automataStateNames.size(); i++) {
assert (j < i && j >= 0);
if (automataStateNames.get(j).equals(automataStateNames.get(i))) {
if (j + numRootStates - 1 == i) {
// automaton states commonly used
commonAutomataStates.add(automataStateNames.get(j));
}
} else {
j = i;
}
}
// assume root is the root node of the first ARG constructed
ARGState root = rootNodes.iterator().next();
if (root.getWrappedState() instanceof AbstractWrapperState) {
wrapped = ((AbstractWrapperState) root.getWrappedState()).getWrappedStates();
} else {
wrapped = Collections.singleton(root.getWrappedState());
}
for (AbstractState innerWrapped : wrapped) {
shutdown.shutdownIfNecessary();
name = getName(innerWrapped);
if (commonAutomataStates.contains(name)) {
assert (initialState.size() == nextId);
stateToPos.put(name, nextId);
if (!automatonARGBuilderSupport.registerAutomaton((AutomatonState) innerWrapped)) {
logger.log(
Level.SEVERE,
"Property specification, given by automata specification, is ambigous.");
throw new CPAException(
"Ambigious property specification, automata specification contains automata with same name or same state names");
}
initialState.add(
automatonARGBuilderSupport.replaceStateByStateInAutomatonOfSameInstance(
(AutomatonState) innerWrapped));
nextId++;
}
}
return Pair.of(stateToPos, initialState);
}
@Override
public Collection<? extends AbstractState> getAbstractSuccessorsForEdge(
AbstractState pElement, Precision pPrecision, CFAEdge pCfaEdge) throws CPATransferException {
Preconditions.checkArgument(pElement instanceof AutomatonState);
if (pElement instanceof AutomatonUnknownState) {
// the last CFA edge could not be processed properly
// (strengthen was not called on the AutomatonUnknownState or the strengthen operation had not
// enough information to determine a new following state.)
AutomatonState top = cpa.getTopState();
return Collections.singleton(top);
}
if (!(pCfaEdge instanceof MultiEdge)) {
Collection<? extends AbstractState> result =
getAbstractSuccessors0((AutomatonState) pElement, pPrecision, pCfaEdge);
automatonSuccessors.setNextValue(result.size());
return result;
}
final List<CFAEdge> edges = ((MultiEdge) pCfaEdge).getEdges();
checkArgument(!edges.isEmpty());
// As long as each transition produces only 0 or 1 successors,
// we can just iterate through the edges.
AutomatonState currentState = (AutomatonState) pElement;
Collection<AutomatonState> currentSuccessors = null;
int edgeIndex;
for (edgeIndex = 0; edgeIndex < edges.size(); edgeIndex++) {
CFAEdge edge = edges.get(edgeIndex);
currentSuccessors = getAbstractSuccessors0(currentState, pPrecision, edge);
if (currentSuccessors.isEmpty()) {
automatonSuccessors.setNextValue(0);
return currentSuccessors; // bottom
} else if (currentSuccessors.size() == 1) {
automatonSuccessors.setNextValue(1);
currentState = Iterables.getOnlyElement(currentSuccessors);
} else { // currentSuccessors.size() > 1
break;
}
}
if (edgeIndex == edges.size()) {
automatonSuccessors.setNextValue(currentSuccessors.size());
return currentSuccessors;
}
// If there are two or more successors once, we use a waitlist algorithm.
Deque<Pair<AutomatonState, Integer>> queue = new ArrayDeque<>(1);
for (AutomatonState successor : currentSuccessors) {
queue.addLast(Pair.of(successor, edgeIndex));
}
currentSuccessors.clear();
List<AutomatonState> results = new ArrayList<>();
while (!queue.isEmpty()) {
Pair<AutomatonState, Integer> entry = queue.pollFirst();
AutomatonState state = entry.getFirst();
edgeIndex = entry.getSecond();
CFAEdge edge = edges.get(edgeIndex);
Integer successorIndex = edgeIndex + 1;
if (successorIndex == edges.size()) {
// last iteration
results.addAll(getAbstractSuccessors0(state, pPrecision, edge));
} else {
for (AutomatonState successor : getAbstractSuccessors0(state, pPrecision, edge)) {
queue.addLast(Pair.of(successor, successorIndex));
}
}
}
automatonSuccessors.setNextValue(results.size());
return results;
}
private boolean combineARGs(
List<ARGState> roots,
ForwardingReachedSet pReceivedReachedSet,
HistoryForwardingReachedSet pForwaredReachedSet)
throws InterruptedException, CPAException {
Pair<Map<String, Integer>, List<AbstractState>> initStates =
identifyCompositeStateTypesAndTheirInitialInstances(roots);
Map<String, Integer> stateToPos = initStates.getFirst();
List<AbstractState> initialStates = initStates.getSecond();
try {
pReceivedReachedSet.setDelegate(new ReachedSetFactory(config, logger).create());
} catch (InvalidConfigurationException e) {
logger.log(Level.SEVERE, "Creating reached set which should contain combined ARG fails.");
return false;
}
shutdown.shutdownIfNecessary();
// combined root
ARGState combinedRoot = new ARGState(new CompositeState(initialStates), null);
CFANode locPred;
ARGState composedState, composedSuccessor;
Collection<ARGState> components;
List<List<ARGState>> successorsForEdge = new ArrayList<>(initialStates.size());
EdgeSuccessor edgeSuccessorIdentifier = new EdgeSuccessor();
Map<Pair<List<AbstractState>, List<ARGState>>, ARGState> constructedCombinedStates =
Maps.newHashMap();
Deque<Pair<List<ARGState>, ARGState>> toVisit = new ArrayDeque<>();
toVisit.add(Pair.of(roots, combinedRoot));
// traverse through ARGs and construct combined ARG
// assume that states in initial states are most general, represent top state (except for
// automaton CPAs)
while (!toVisit.isEmpty()) {
shutdown.shutdownIfNecessary();
components = toVisit.peek().getFirst();
composedState = toVisit.poll().getSecond();
// add composed state to reached set
pReceivedReachedSet.add(composedState, SingletonPrecision.getInstance());
pReceivedReachedSet.removeOnlyFromWaitlist(composedState);
// identify possible successor edges
locPred = AbstractStates.extractLocation(composedState);
nextEdge:
for (CFAEdge succEdge : CFAUtils.allLeavingEdges(locPred)) {
shutdown.shutdownIfNecessary();
successorsForEdge.clear();
edgeSuccessorIdentifier.setCFAEdge(succEdge);
for (ARGState component : components) {
// get the successors of ARG state for this edge succEdge
edgeSuccessorIdentifier.setPredecessor(component);
successorsForEdge.add(
Lists.newArrayList(
Iterables.filter(component.getChildren(), edgeSuccessorIdentifier)));
// check if stopped because no concrete successors exists, then do not
if (successorsForEdge.get(successorsForEdge.size() - 1).isEmpty()
&& noConcreteSuccessorExist(component, succEdge, pForwaredReachedSet)) {
continue nextEdge;
}
}
// construct successors for each identified combination
for (Pair<List<AbstractState>, List<ARGState>> combinedSuccessor :
computeCartesianProduct(successorsForEdge, stateToPos, initialStates)) {
if (constructedCombinedStates.containsKey(combinedSuccessor)) {
// handle coverage
constructedCombinedStates.get(combinedSuccessor).addParent(composedState);
} else {
// construct and register composed successor
composedSuccessor =
new ARGState(new CompositeState(combinedSuccessor.getFirst()), composedState);
constructedCombinedStates.put(combinedSuccessor, composedSuccessor);
// add successor for further exploration
toVisit.add(Pair.of(combinedSuccessor.getSecond(), composedSuccessor));
}
}
}
}
return true;
}
/**
* Returns the <code>AutomatonStates</code> that follow this State in the ControlAutomatonCPA. If
* the passed <code>AutomatonExpressionArguments</code> are not sufficient to determine the
* following state this method returns a <code>AutomatonUnknownState</code> that contains this as
* previous State. The strengthen method of the <code>AutomatonUnknownState</code> should be used
* once enough Information is available to determine the correct following State.
*
* <p>If the state is a NonDet-State multiple following states may be returned. If the only
* following state is BOTTOM an empty set is returned.
*
* @throws CPATransferException
*/
private Collection<AutomatonState> getFollowStates(
AutomatonState state,
List<AbstractState> otherElements,
CFAEdge edge,
boolean failOnUnknownMatch)
throws CPATransferException {
Preconditions.checkArgument(!(state instanceof AutomatonUnknownState));
if (state == cpa.getBottomState()) {
return Collections.emptySet();
}
if (collectTokenInformation) {
SourceLocationMapper.getKnownToEdge(edge);
}
if (state.getInternalState().getTransitions().isEmpty()) {
// shortcut
return Collections.singleton(state);
}
Collection<AutomatonState> lSuccessors = Sets.newHashSetWithExpectedSize(2);
AutomatonExpressionArguments exprArgs =
new AutomatonExpressionArguments(state, state.getVars(), otherElements, edge, logger);
boolean edgeMatched = false;
int failedMatches = 0;
boolean nonDetState = state.getInternalState().isNonDetState();
// these transitions cannot be evaluated until last, because they might have sideeffects on
// other CPAs (dont want to execute them twice)
// the transitionVariables have to be cached (produced during the match operation)
// the list holds a Transition and the TransitionVariables generated during its match
List<Pair<AutomatonTransition, Map<Integer, String>>> transitionsToBeTaken = new ArrayList<>(2);
for (AutomatonTransition t : state.getInternalState().getTransitions()) {
exprArgs.clearTransitionVariables();
matchTime.start();
ResultValue<Boolean> match = t.match(exprArgs);
matchTime.stop();
// System.out.println("----------------------");
// System.out.println(t.getTrigger());
// System.out.println(t.getFollowState().getName());
// System.out.println(edge.getPredecessor().getNodeNumber());
// System.out.println(edge.getCode());
// System.out.println(match.getValue());
if (match.canNotEvaluate()) {
if (failOnUnknownMatch) {
throw new CPATransferException(
"Automaton transition condition could not be evaluated: "
+ match.getFailureMessage());
}
// if one transition cannot be evaluated the evaluation must be postponed until enough
// information is available
return Collections.<AutomatonState>singleton(new AutomatonUnknownState(state));
} else {
if (match.getValue()) {
edgeMatched = true;
assertionsTime.start();
ResultValue<Boolean> assertionsHold = t.assertionsHold(exprArgs);
assertionsTime.stop();
if (assertionsHold.canNotEvaluate()) {
if (failOnUnknownMatch) {
throw new CPATransferException(
"Automaton transition assertions could not be evaluated: "
+ assertionsHold.getFailureMessage());
}
// cannot yet be evaluated
return Collections.<AutomatonState>singleton(new AutomatonUnknownState(state));
} else if (assertionsHold.getValue()) {
if (!t.canExecuteActionsOn(exprArgs)) {
if (failOnUnknownMatch) {
throw new CPATransferException("Automaton transition action could not be executed");
}
// cannot yet execute, goto UnknownState
return Collections.<AutomatonState>singleton(new AutomatonUnknownState(state));
}
// delay execution as described above
Map<Integer, String> transitionVariables =
ImmutableMap.copyOf(exprArgs.getTransitionVariables());
transitionsToBeTaken.add(Pair.of(t, transitionVariables));
} else {
// matching transitions, but unfulfilled assertions: goto error state
AutomatonState errorState =
AutomatonState.automatonStateFactory(
Collections.<String, AutomatonVariable>emptyMap(),
AutomatonInternalState.ERROR,
cpa,
0,
0,
"");
logger.log(
Level.INFO,
"Automaton going to ErrorState on edge \"" + edge.getDescription() + "\"");
lSuccessors.add(errorState);
}
if (!nonDetState) {
// not a nondet State, break on the first matching edge
break;
}
} else {
// do nothing if the edge did not match
failedMatches++;
}
}
}
if (edgeMatched) {
// execute Transitions
for (Pair<AutomatonTransition, Map<Integer, String>> pair : transitionsToBeTaken) {
// this transition will be taken. copy the variables
AutomatonTransition t = pair.getFirst();
Map<Integer, String> transitionVariables = pair.getSecond();
actionTime.start();
Map<String, AutomatonVariable> newVars = deepCloneVars(state.getVars());
exprArgs.setAutomatonVariables(newVars);
exprArgs.putTransitionVariables(transitionVariables);
t.executeActions(exprArgs);
actionTime.stop();
String violatedPropertyDescription = null;
if (t.getFollowState().isTarget()) {
violatedPropertyDescription = t.getViolatedPropertyDescription(exprArgs);
}
AutomatonState lSuccessor =
AutomatonState.automatonStateFactory(
newVars,
t.getFollowState(),
cpa,
t.getAssumptions(),
state.getMatches() + 1,
state.getFailedMatches(),
violatedPropertyDescription);
if (!(lSuccessor instanceof AutomatonState.BOTTOM)) {
lSuccessors.add(lSuccessor);
} else {
// add nothing
}
}
return lSuccessors;
} else {
// stay in same state, no transitions to be executed here (no transition matched)
AutomatonState stateNewCounters =
AutomatonState.automatonStateFactory(
state.getVars(),
state.getInternalState(),
cpa,
state.getMatches(),
state.getFailedMatches() + failedMatches,
null);
if (collectTokenInformation) {
stateNewCounters.addNoMatchTokens(state.getTokensSinceLastMatch());
if (edge.getEdgeType() != CFAEdgeType.DeclarationEdge) {
stateNewCounters.addNoMatchTokens(
SourceLocationMapper.getAbsoluteTokensFromCFAEdge(edge, true));
}
}
return Collections.singleton(stateNewCounters);
}
}
