import gov.nasa.jpf.vm.choice.IntChoiceFromSet;
import gov.nasa.jpf.vm.choice.IntIntervalGenerator;
+import java.awt.*;
import java.io.PrintWriter;
import java.util.*;
// DPOR-related fields
// Basic information
private Integer[] choices;
- private Integer[] refChoices;
+ private Integer[] refChoices; // Second reference to a copy of choices (choices may be modified for fair scheduling)
private int choiceCounter;
private int maxEventChoice;
// Data structure to track the events seen by each state to track cycles (containing all events) for termination
private HashSet<Integer> prevVisitedStates; // States visited in the previous execution
private HashMap<Integer, HashSet<Integer>> stateToEventMap;
// Data structure to analyze field Read/Write accesses and conflicts
- private HashMap<Integer, LinkedList<Integer[]>> backtrackMap; // Track created backtracking points
- private PriorityQueue<Integer> backtrackStateQ; // Heap that returns the latest state
- private ArrayList<IntChoiceFromSet> cgList; // Record CGs for backtracking points
- private HashMap<Integer, IntChoiceFromSet> cgMap; // Maps state IDs to CGs
- private HashMap<Integer, HashSet<Integer>> conflictPairMap; // Record conflicting events
-// private HashSet<IntChoiceFromSet> activeBacktrackCGs; // Record active backtrack CGs
- private HashMap<Integer, ReadWriteSet> readWriteFieldsMap; // Record fields that are accessed
+ private HashMap<Integer, LinkedList<Integer[]>> backtrackMap; // Track created backtracking points
+ private PriorityQueue<Integer> backtrackStateQ; // Heap that returns the latest state
+ private ArrayList<BacktrackPoint> backtrackPointList; // Record backtrack points (CG, state Id, and choice)
+ private HashMap<Integer, HashSet<Integer>> conflictPairMap; // Record conflicting events
+ private HashSet<String> doneBacktrackSet; // Record state ID and trace that are done
+ private HashMap<Integer, ReadWriteSet> readWriteFieldsMap; // Record fields that are accessed
+ private HashMap<Integer, RestorableVMState> restorableStateMap; // Maps state IDs to the restorable state object
// Visible operation dependency graph implementation (SPIN paper) related fields
private int prevChoiceValue;
// Boolean states
private boolean isBooleanCGFlipped;
- private boolean isFirstResetDone;
private boolean isEndOfExecution;
public DPORStateReducer(Config config, JPF jpf) {
} else {
out = null;
}
- // DPOR-related
- choices = null;
- refChoices = null;
- choiceCounter = 0;
- maxEventChoice = 0;
- // Cycle tracking
- currVisitedStates = new HashSet<>();
- justVisitedStates = new HashSet<>();
- prevVisitedStates = new HashSet<>();
- stateToEventMap = new HashMap<>();
- // Backtracking
- backtrackMap = new HashMap<>();
- backtrackStateQ = new PriorityQueue<>();
- cgList = new ArrayList<>();
- cgMap = new HashMap<>();
- conflictPairMap = new HashMap<>();
-// activeBacktrackCGs = new HashSet<>();
- readWriteFieldsMap = new HashMap<>();
- // VOD graph
- prevChoiceValue = -1;
- vodGraphMap = new HashMap<>();
- // Booleans
isBooleanCGFlipped = false;
- isEndOfExecution = false;
- isFirstResetDone = false;
+ restorableStateMap = new HashMap<>();
+ initializeStatesVariables();
}
@Override
// Use a modulo since choiceCounter is going to keep increasing
int choiceIndex = choiceCounter % choices.length;
icsCG.advance(choices[choiceIndex]);
- // Index the ChoiceGenerator to set backtracking points
- cgList.add(icsCG);
} else {
// Set done all CGs while transitioning to a new execution
icsCG.setDone();
if (stateReductionMode) {
// Check the boolean CG and if it is flipped, we are resetting the analysis
-// if (currentCG instanceof BooleanChoiceGenerator) {
-// if (!isBooleanCGFlipped) {
-// isBooleanCGFlipped = true;
-// } else {
-// initializeStateReduction();
-// }
-// }
+ if (currentCG instanceof BooleanChoiceGenerator) {
+ if (!isBooleanCGFlipped) {
+ isBooleanCGFlipped = true;
+ } else {
+ // Allocate new objects for data structure when the boolean is flipped from "false" to "true"
+ initializeStatesVariables();
+ }
+ }
// Check every choice generated and ensure fair scheduling!
if (currentCG instanceof IntChoiceFromSet) {
IntChoiceFromSet icsCG = (IntChoiceFromSet) currentCG;
// If this is a new CG then we need to update data structures
- resetStatesForNewExecution(icsCG);
+ resetStatesForNewExecution(icsCG, vm);
// If we don't see a fair scheduling of events/choices then we have to enforce it
- checkAndEnforceFairScheduling(icsCG);
+ fairSchedulingAndBacktrackPoint(icsCG, vm);
// Map state to event
mapStateToEvent(icsCG.getNextChoice());
// Update the VOD graph always with the latest
updateVODGraph(icsCG.getNextChoice());
// Check if we have seen this state or this state contains cycles that involve all events
if (terminateCurrentExecution()) {
- exploreNextBacktrackPoints(icsCG, vm);
+ exploreNextBacktrackPoints(vm, icsCG);
}
justVisitedStates.clear();
choiceCounter++;
}
}
- // This class compactly stores backtracking points: 1) backtracking ChoiceGenerator, and 2) backtracking choices
+ // This class compactly stores backtrack points: 1) backtrack state ID, and 2) backtracking choices
private class BacktrackPoint {
- private IntChoiceFromSet backtrackCG; // CG to backtrack from
- private Integer[] backtrackChoices; // Choices to set for this backtrack CG
+ private IntChoiceFromSet backtrackCG; // CG at this backtrack point
+ private int stateId; // State at this backtrack point
+ private int choice; // Choice chosen at this backtrack point
- public BacktrackPoint(IntChoiceFromSet cg, Integer[] choices) {
+ public BacktrackPoint(IntChoiceFromSet cg, int stId, int cho) {
backtrackCG = cg;
- backtrackChoices = choices;
+ stateId = stId;
+ choice = cho;
}
- public IntChoiceFromSet getBacktrackCG() {
- return backtrackCG;
+ public IntChoiceFromSet getBacktrackCG() { return backtrackCG; }
+
+ public int getStateId() {
+ return stateId;
}
- public Integer[] getBacktrackChoices() {
- return backtrackChoices;
+ public int getChoice() {
+ return choice;
}
}
private final static String JAVA_STRING_LIB = "java.lang.String";
// -- FUNCTIONS
- private void checkAndEnforceFairScheduling(IntChoiceFromSet icsCG) {
+ private void fairSchedulingAndBacktrackPoint(IntChoiceFromSet icsCG, VM vm) {
// Check the next choice and if the value is not the same as the expected then force the expected value
int choiceIndex = choiceCounter % refChoices.length;
int nextChoice = icsCG.getNextChoice();
icsCG.setChoice(currCGIndex, expectedChoice);
}
}
+ // Record state ID and choice/event as backtrack point
+ int stateId = vm.getStateId();
+ backtrackPointList.add(new BacktrackPoint(icsCG, stateId, refChoices[choiceIndex]));
+ // Store restorable state object for this state (always store the latest)
+ RestorableVMState restorableState = vm.getRestorableState();
+ restorableStateMap.put(stateId, restorableState);
}
private Integer[] copyChoices(Integer[] choicesToCopy) {
return true;
}
+ private void initializeStatesVariables() {
+ // DPOR-related
+ choices = null;
+ refChoices = null;
+ choiceCounter = 0;
+ maxEventChoice = 0;
+ // Cycle tracking
+ currVisitedStates = new HashSet<>();
+ justVisitedStates = new HashSet<>();
+ prevVisitedStates = new HashSet<>();
+ stateToEventMap = new HashMap<>();
+ // Backtracking
+ backtrackMap = new HashMap<>();
+ backtrackStateQ = new PriorityQueue<>(Collections.reverseOrder());
+ backtrackPointList = new ArrayList<>();
+ conflictPairMap = new HashMap<>();
+ doneBacktrackSet = new HashSet<>();
+ readWriteFieldsMap = new HashMap<>();
+ // VOD graph
+ prevChoiceValue = -1;
+ vodGraphMap = new HashMap<>();
+ // Booleans
+ isEndOfExecution = false;
+ }
+
private void mapStateToEvent(int nextChoiceValue) {
// Update all states with this event/choice
// This means that all past states now see this transition
// --- Functions related to Read/Write access analysis on shared fields
- private void addNewBacktrackPoint(IntChoiceFromSet backtrackCG, Integer[] newChoiceList) {
- int stateId = backtrackCG.getStateId();
+ private void addNewBacktrackPoint(int stateId, Integer[] newChoiceList) {
// Insert backtrack point to the right state ID
LinkedList<Integer[]> backtrackList;
if (backtrackMap.containsKey(stateId)) {
backtrackList = backtrackMap.get(stateId);
} else {
backtrackList = new LinkedList<>();
+ backtrackMap.put(stateId, backtrackList);
}
backtrackList.addFirst(newChoiceList);
- // Add CG for this state ID if there isn't one yet
- if (!cgMap.containsKey(stateId)) {
- cgMap.put(stateId, backtrackCG);
- }
// Add to priority queue
if (!backtrackStateQ.contains(stateId)) {
backtrackStateQ.add(stateId);
// If current choice is not the same, then this is caused by the firing of IntIntervalGenerator
// for certain method calls in the infrastructure, e.g., eventSince()
int currChoiceInd = currentChoice % refChoices.length;
- int currChoiceFromCG = getCurrentChoice(vm);
+ int currChoiceFromCG = currChoiceInd;
+ ChoiceGenerator<?> currentCG = vm.getChoiceGenerator();
+ // This is the main event CG
+ if (currentCG instanceof IntIntervalGenerator) {
+ // This is the interval CG used in device handlers
+ ChoiceGenerator<?> parentCG = ((IntIntervalGenerator) currentCG).getPreviousChoiceGenerator();
+ int actualEvtNum = ((IntChoiceFromSet) parentCG).getNextChoice();
+ // Find the index of the event/choice in refChoices
+ for (int i = 0; i<refChoices.length; i++) {
+ if (actualEvtNum == refChoices[i]) {
+ currChoiceFromCG = i;
+ break;
+ }
+ }
+ }
if (currChoiceInd != currChoiceFromCG) {
currentChoice = (currentChoice - currChoiceInd) + currChoiceFromCG;
}
Integer[] newChoiceList = new Integer[refChoices.length];
// Put the conflicting event numbers first and reverse the order
int actualCurrCho = currentChoice % refChoices.length;
- int actualConfEvtNum = confEvtNum % refChoices.length;
- newChoiceList[0] = refChoices[actualCurrCho];
- newChoiceList[1] = refChoices[actualConfEvtNum];
+ // We use the actual choices here in case they have been modified/adjusted by the fair scheduling method
+ newChoiceList[0] = choices[actualCurrCho];
+ 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++) {
if (refChoices[i] != newChoiceList[0] && refChoices[i] != newChoiceList[1]) {
j++;
}
}
- // Record the backtracking point in the stack as well
- IntChoiceFromSet backtrackCG = cgList.get(confEvtNum);
- //BacktrackPoint backtrackPoint = new BacktrackPoint(backtrackCG, newChoiceList);
- addNewBacktrackPoint(backtrackCG, newChoiceList);
+ // Get the backtrack CG for this backtrack point
+ int stateId = backtrackPointList.get(confEvtNum).getStateId();
+ // Check if this trace has been done starting from this state
+ if (isTraceConstructed(newChoiceList, stateId)) {
+ return;
+ }
+ addNewBacktrackPoint(stateId, newChoiceList);
}
private boolean excludeThisForItContains(String[] excludedStrings, String className) {
return false;
}
- private void exploreNextBacktrackPoints(IntChoiceFromSet icsCG, VM vm) {
+ private void exploreNextBacktrackPoints(VM vm, IntChoiceFromSet icsCG) {
+
// We can start exploring the next backtrack point after the current CG is advanced at least once
- if (icsCG.getNextChoiceIndex() > 0) {
- if (backtrackMap.isEmpty()) {
- // This means we are reaching the end of our execution: no more backtracking points to explore
- return;
+ if (choiceCounter > 0) {
+ // Check if we are reaching the end of our execution: no more backtracking points to explore
+ // cgMap, backtrackMap, backtrackStateQ are updated simultaneously (checking backtrackStateQ is enough)
+ if (!backtrackStateQ.isEmpty()) {
+ // Set done all the other backtrack points
+ for (BacktrackPoint backtrackPoint : backtrackPointList) {
+ backtrackPoint.getBacktrackCG().setDone();
+ }
+ // Reset the next backtrack point with the latest state
+ int hiStateId = backtrackStateQ.peek();
+ // Restore the state first if necessary
+ if (vm.getStateId() != hiStateId) {
+ RestorableVMState restorableState = restorableStateMap.get(hiStateId);
+ vm.restoreState(restorableState);
+ }
+ // Set the backtrack CG
+ IntChoiceFromSet backtrackCG = (IntChoiceFromSet) vm.getChoiceGenerator();
+ setBacktrackCG(hiStateId, backtrackCG);
+ } else {
+ // Set done this last CG (we save a few rounds)
+ icsCG.setDone();
}
- setNextBacktrackPoint(icsCG);
// Save all the visited states when starting a new execution of trace
prevVisitedStates.addAll(currVisitedStates);
currVisitedStates.clear();
}
}
- private int getCurrentChoice(VM vm) {
- ChoiceGenerator<?> currentCG = vm.getChoiceGenerator();
- // This is the main event CG
- if (currentCG instanceof IntChoiceFromSet) {
- return ((IntChoiceFromSet) currentCG).getNextChoiceIndex();
- } else {
- // This is the interval CG used in device handlers
- ChoiceGenerator<?> parentCG = ((IntIntervalGenerator) currentCG).getPreviousChoiceGenerator();
- return ((IntChoiceFromSet) parentCG).getNextChoiceIndex();
- }
- }
-
private ReadWriteSet getReadWriteSet(int currentChoice) {
// Do the analysis to get Read and Write accesses to fields
ReadWriteSet rwSet;
}
private boolean isConflictFound(Instruction nextInsn, int eventCounter, int currentChoice, String fieldClass) {
- int actualEvtCntr = eventCounter % refChoices.length;
+
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) || (actualEvtCntr == actualCurrCho)) {
+ if (!readWriteFieldsMap.containsKey(eventCounter) ||
+ choices[actualCurrCho] == backtrackPointList.get(eventCounter).getChoice()) {
return false;
}
ReadWriteSet rwSet = readWriteFieldsMap.get(eventCounter);
return true;
}
- private void resetStatesForNewExecution(IntChoiceFromSet icsCG) {
+ private boolean isTraceConstructed(Integer[] choiceList, int stateId) {
+ // Concatenate state ID and trace in a string, e.g., "1:10234"
+ StringBuilder sb = new StringBuilder();
+ sb.append(stateId);
+ sb.append(':');
+ for(Integer choice : choiceList) {
+ sb.append(choice);
+ }
+ // Check if the trace has been constructed as a backtrack point for this state
+ if (doneBacktrackSet.contains(sb.toString())) {
+ return true;
+ }
+ doneBacktrackSet.add(sb.toString());
+ return false;
+ }
+
+ private void resetStatesForNewExecution(IntChoiceFromSet icsCG, VM vm) {
if (choices == null || choices != icsCG.getAllChoices()) {
// Reset state variables
choiceCounter = 0;
choices = icsCG.getAllChoices();
refChoices = copyChoices(choices);
// Clearing data structures
- backtrackMap.clear();
conflictPairMap.clear();
readWriteFieldsMap.clear();
stateToEventMap.clear();
isEndOfExecution = false;
+ backtrackPointList.clear();
}
}
- private IntChoiceFromSet setBacktrackCG(int stateId) {
+ private void setBacktrackCG(int stateId, IntChoiceFromSet backtrackCG) {
// Set a backtrack CG based on a state ID
- IntChoiceFromSet backtrackCG = cgMap.get(stateId);
LinkedList<Integer[]> backtrackChoices = backtrackMap.get(stateId);
backtrackCG.setNewValues(backtrackChoices.removeLast()); // Get the last from the queue
+ backtrackCG.setStateId(stateId);
backtrackCG.reset();
// Remove from the queue if we don't have more backtrack points for that state
if (backtrackChoices.isEmpty()) {
- cgMap.remove(stateId);
backtrackMap.remove(stateId);
backtrackStateQ.remove(stateId);
}
- return backtrackCG;
- }
-
- private void setNextBacktrackPoint(IntChoiceFromSet icsCG) {
-
- HashSet<IntChoiceFromSet> backtrackCGs = new HashSet<>(cgMap.values());
- if (!isFirstResetDone) {
- // Reset the last CG of every LinkedList in the map and set done everything else
- for (Integer stateId : cgMap.keySet()) {
- setBacktrackCG(stateId);
- }
-// activeBacktrackCGs.addAll(cgMap.values());
- isFirstResetDone = true;
- } else {
- // Check if we still have backtrack points for the current CG
- int currStateId = icsCG.getStateId();
- if (backtrackMap.containsKey(currStateId)) {
- setBacktrackCG(currStateId);
- } else {
-// activeBacktrackCGs.remove(icsCG);
- // We try to reset new CGs (if we do have) when we are running out of active CGs
- if (!backtrackStateQ.isEmpty()) {
- // Reset the next CG with the latest state
- int hiStateId = backtrackStateQ.peek();
- IntChoiceFromSet backtrackCG = setBacktrackCG(hiStateId);
-// activeBacktrackCGs.add(backtrackCG);
- }
- }
- }
- // Clear unused CGs
- for(IntChoiceFromSet cg : cgList) {
- if (!backtrackCGs.contains(cg)) {
- cg.setDone();
- }
- }
- cgList.clear();
}
// --- Functions related to the visible operation dependency graph implementation discussed in the SPIN paper
private boolean isReachableInVODGraph(int currentChoice) {
// Extract previous and current events
int choiceIndex = currentChoice % refChoices.length;
+ int prevChoIndex = (currentChoice - 1) % refChoices.length;
int currEvent = refChoices[choiceIndex];
- int prevEvent = refChoices[choiceIndex - 1];
+ int prevEvent = refChoices[prevChoIndex];
// Record visited choices as we search in the graph
HashSet<Integer> visitedChoice = new HashSet<>();
visitedChoice.add(prevEvent);
projects / jpf-core.git / blobdiff