private HashMap<Integer, ReadWriteSet> readWriteFieldsMap; // Record fields that are accessed
private HashMap<Integer, RestorableVMState> restorableStateMap; // Maps state IDs to the restorable state object
private HashMap<Integer, Integer> stateToChoiceCounterMap; // Maps state IDs to the choice counter
+ private HashMap<Integer, ReachabilityGraph> stateToRGraph; // Maps state IDs to a ReachabilityGraph
// Boolean states
private boolean isBooleanCGFlipped;
// 1) if we have seen this state or this state contains cycles that involve all events, and
// 2) after the current CG is advanced at least once
if (terminateCurrentExecution() && choiceCounter > 0) {
+ saveExecutionInfo();
exploreNextBacktrackPoints(vm, icsCG);
} else {
numOfTransitions++;
}
}
+ // This class stores a compact representation of a reachability graph for past executions
+ private class ReachabilityGraph {
+ private ArrayList<BacktrackPoint> pastBacktrackPointList;
+ private HashMap<Integer, ReadWriteSet> pastReadWriteFieldsMap;
+
+ public ReachabilityGraph(ArrayList<BacktrackPoint> btrackPointList,
+ HashMap<Integer, ReadWriteSet> rwFieldsMap) {
+ pastBacktrackPointList = btrackPointList;
+ pastReadWriteFieldsMap = rwFieldsMap;
+ }
+
+ public ArrayList<BacktrackPoint> getPastBacktrackPointList() {
+ return pastBacktrackPointList;
+ }
+
+ public HashMap<Integer, ReadWriteSet> getPastReadWriteFieldsMap() {
+ return pastReadWriteFieldsMap;
+ }
+ }
+
// -- CONSTANTS
private final static String DO_CALL_METHOD = "doCall";
// We exclude fields that come from libraries (Java and Groovy), and also the infrastructure
doneBacktrackSet = new HashSet<>();
readWriteFieldsMap = new HashMap<>();
stateToChoiceCounterMap = new HashMap<>();
+ stateToRGraph = new HashMap<>();
// Booleans
isEndOfExecution = false;
}
// for the original set {0, 1, 2, 3}
Integer[] newChoiceList = new Integer[refChoices.length];
// Put the conflicting event numbers first and reverse the order
- int actualCurrCho = currentChoice % refChoices.length;
// We use the actual choices here in case they have been modified/adjusted by the fair scheduling method
- newChoiceList[0] = choices[actualCurrCho];
+ newChoiceList[0] = backtrackPointList.get(currentChoice).getChoice();
newChoiceList[1] = backtrackPointList.get(confEvtNum).getChoice();
// Put the rest of the event numbers into the array starting from the minimum to the upper bound
for (int i = 0, j = 2; i < refChoices.length; i++) {
private boolean isConflictFound(int eventCounter, int currentChoice) {
- int actualCurrCho = currentChoice % refChoices.length;
// Skip if this event does not have any Read/Write set or the two events are basically the same event (number)
if (!readWriteFieldsMap.containsKey(eventCounter) ||
- choices[actualCurrCho] == backtrackPointList.get(eventCounter).getChoice()) {
+ backtrackPointList.get(currentChoice).getChoice() == backtrackPointList.get(eventCounter).getChoice()) {
return false;
}
// Current R/W set
choiceCounter = 0;
choices = icsCG.getAllChoices();
refChoices = copyChoices(choices);
- // Clearing data structures
- conflictPairMap.clear();
- readWriteFieldsMap.clear();
- stateToEventMap.clear();
+ // Clear data structures
+ backtrackPointList = new ArrayList<>();
+ conflictPairMap = new HashMap<>();
+ readWriteFieldsMap = new HashMap<>();
+ stateToChoiceCounterMap = new HashMap<>();
+ stateToEventMap = new HashMap<>();
isEndOfExecution = false;
- backtrackPointList.clear();
}
}
// 3) at least 2 choices/events have been explored (choiceCounter > 1),
// 4) the matched state has been encountered in the current execution, and
// 5) state > 0 (state 0 is for boolean CG)
- if (!vm.isNewState() && !isEndOfExecution && choiceCounter > 1 &&
- currVisitedStates.contains(stateId) && (stateId > 0)) {
- // Find the choice/event that marks the start of this cycle: first choice we explore for conflicts
- int conflictChoice = stateToChoiceCounterMap.get(stateId);
- int currentChoice = choiceCounter - 1;
- // Find conflicts between choices/events in this cycle (we scan forward in the cycle, not backward)
- while (conflictChoice < currentChoice) {
- for (int eventCounter = conflictChoice + 1; eventCounter <= currentChoice; eventCounter++) {
- if (isConflictFound(eventCounter, conflictChoice) && isNewConflict(conflictChoice, eventCounter)) {
- createBacktrackingPoint(conflictChoice, eventCounter);
- }
+ if (!vm.isNewState() && !isEndOfExecution && choiceCounter > 1 && (stateId > 0)) {
+ if (currVisitedStates.contains(stateId)) {
+ // Update the backtrack sets in the cycle
+ updateBacktrackSetsInCycle(stateId);
+ } else if (prevVisitedStates.contains(stateId)) { // We visit a state in a previous execution
+ // Update the backtrack sets in a previous execution
+ updateBacktrackSetsInPreviousExecution(stateId);
+ }
+ }
+ }
+
+ // Save the information from this execution for future reachability analysis
+ private void saveExecutionInfo() {
+ Set<Integer> states = stateToChoiceCounterMap.keySet();
+ ReachabilityGraph reachabilityGraph = new
+ ReachabilityGraph(backtrackPointList, readWriteFieldsMap);
+ // Map all the states visited in this execution to the same ReachabilityGraph object for fast access
+ for(Integer state : states) {
+ if (!prevVisitedStates.contains(state)) {
+ stateToRGraph.put(state, reachabilityGraph);
+ }
+ }
+ }
+
+ // Update the backtrack sets in the cycle
+ private void updateBacktrackSetsInCycle(int stateId) {
+ // Find the choice/event that marks the start of this cycle: first choice we explore for conflicts
+ int conflictChoice = stateToChoiceCounterMap.get(stateId);
+ int currentChoice = choiceCounter - 1;
+ // Find conflicts between choices/events in this cycle (we scan forward in the cycle, not backward)
+ while (conflictChoice < currentChoice) {
+ for (int eventCounter = conflictChoice + 1; eventCounter <= currentChoice; eventCounter++) {
+ if (isConflictFound(eventCounter, conflictChoice) && isNewConflict(conflictChoice, eventCounter)) {
+ createBacktrackingPoint(conflictChoice, eventCounter);
+ }
+ }
+ conflictChoice++;
+ }
+ }
+
+ private int getPastConflictChoice(int stateId, ArrayList<BacktrackPoint> pastBacktrackPointList) {
+ // Iterate and find the first occurrence of the state ID
+ // It is guaranteed that a choice should be found because the state ID is in the list
+ int pastConfChoice = 0;
+ for(int i = 0; i<pastBacktrackPointList.size(); i++) {
+ BacktrackPoint backtrackPoint = pastBacktrackPointList.get(i);
+ int stId = backtrackPoint.getStateId();
+ if (stId == stateId) {
+ pastConfChoice = i;
+ break;
+ }
+ }
+ return pastConfChoice;
+ }
+
+ // Update the backtrack sets in a previous execution
+ private void updateBacktrackSetsInPreviousExecution(int stateId) {
+ // Find the right ReachabilityGraph object that contains the stateId
+ ReachabilityGraph rGraph = stateToRGraph.get(stateId);
+ // Find the choice/event that marks the start of the subtrace from the previous execution
+ ArrayList<BacktrackPoint> pastBacktrackPointList = rGraph.getPastBacktrackPointList();
+ HashMap<Integer, ReadWriteSet> pastReadWriteFieldsMap = rGraph.getPastReadWriteFieldsMap();
+ int pastConfChoice = getPastConflictChoice(stateId, pastBacktrackPointList);
+ int conflictChoice = choiceCounter;
+ // Iterate from the starting point until the end of the past execution trace
+ while (pastConfChoice < pastBacktrackPointList.size() - 1) { // BacktrackPoint list always has a surplus of 1
+ // Get the info of the event from the past execution trace
+ BacktrackPoint confBtrackPoint = pastBacktrackPointList.get(pastConfChoice);
+ ReadWriteSet rwSet = pastReadWriteFieldsMap.get(pastConfChoice);
+ // Append this event to the current list and map
+ backtrackPointList.add(confBtrackPoint);
+ readWriteFieldsMap.put(choiceCounter, rwSet);
+ for (int eventCounter = conflictChoice - 1; eventCounter >= 0; eventCounter--) {
+ if (isConflictFound(eventCounter, conflictChoice) && isNewConflict(conflictChoice, eventCounter)) {
+ createBacktrackingPoint(conflictChoice, eventCounter);
}
- conflictChoice++;
}
+ // Remove this event to replace it with a new one
+ backtrackPointList.remove(backtrackPointList.size() - 1);
+ readWriteFieldsMap.remove(choiceCounter);
+ pastConfChoice++;
}
}
}
projects / jpf-core.git / commitdiff