--- /dev/null
+/*
+ * Copyright (C) 2014, United States Government, as represented by the
+ * Administrator of the National Aeronautics and Space Administration.
+ * All rights reserved.
+ *
+ * The Java Pathfinder core (jpf-core) platform is 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 gov.nasa.jpf.listener;
+
+import gov.nasa.jpf.Config;
+import gov.nasa.jpf.JPF;
+import gov.nasa.jpf.ListenerAdapter;
+import gov.nasa.jpf.search.Search;
+import gov.nasa.jpf.jvm.bytecode.*;
+import gov.nasa.jpf.vm.*;
+import gov.nasa.jpf.vm.bytecode.ReadInstruction;
+import gov.nasa.jpf.vm.bytecode.WriteInstruction;
+import gov.nasa.jpf.vm.choice.IntChoiceFromSet;
+
+import java.io.PrintWriter;
+
+import java.util.*;
+
+// TODO: Fix for Groovy's model-checking
+// TODO: This is a setter to change the values of the ChoiceGenerator to implement POR
+// TODO: This is a more efficient implementation of StateReducer; it is using the Sleep Sets technique
+/**
+ * simple tool to log state changes
+ */
+public class EfficientStateReducer extends ListenerAdapter {
+
+ // Debug info fields
+ private boolean debugMode;
+ private boolean stateReductionMode;
+ private final PrintWriter out;
+ volatile private String detail;
+ volatile private int depth;
+ volatile private int id;
+ Transition transition;
+
+ // State reduction fields
+ private Integer[] choices;
+ private IntChoiceFromSet currCG;
+ private int choiceCounter;
+ private Integer choiceUpperBound;
+ private boolean isInitialized;
+ private boolean isResetAfterAnalysis;
+ private boolean isBooleanCGFlipped;
+ private HashMap<IntChoiceFromSet,Integer> cgMap = new HashMap<>();
+ // Record the mapping between event number and field accesses (Read and Write)
+ private HashMap<Integer,ReadWriteSet> readWriteFieldsMap = new HashMap<>();
+ // The following is the backtrack map (set) that stores all the backtrack information
+ // e.g., event number 1 can have two backtrack sequences: {3,1,2,4,...} and {2,1,3,4,...}
+ private HashMap<Integer,LinkedList<Integer[]>> backtrackMap = new HashMap<>();
+ private HashMap<Integer,HashSet<Integer>> conflictPairMap = new HashMap<>();
+ private HashMap<Integer,HashSet<Integer>> conflictPairReversedMap = new HashMap<>();
+ private HashMap<Integer,HashSet<Integer>> sleepSetMap = new HashMap<>();
+ // Map choicelist with start index
+ private HashMap<Integer[],Integer> choiceListStartIndexMap = new HashMap<>();
+
+ public EfficientStateReducer (Config config, JPF jpf) {
+ debugMode = config.getBoolean("debug_state_transition", false);
+ stateReductionMode = config.getBoolean("activate_state_reduction", true);
+ if (debugMode) {
+ out = new PrintWriter(System.out, true);
+ } else {
+ out = null;
+ }
+ detail = null;
+ depth = 0;
+ id = 0;
+ transition = null;
+ isBooleanCGFlipped = false;
+ initializeStateReduction();
+ }
+
+ private void initializeStateReduction() {
+ if (stateReductionMode) {
+ choices = null;
+ currCG = null;
+ choiceCounter = 0;
+ choiceUpperBound = 0;
+ isInitialized = false;
+ isResetAfterAnalysis = false;
+ cgMap.clear();
+ readWriteFieldsMap.clear();
+ backtrackMap.clear();
+ conflictPairMap.clear();
+ conflictPairReversedMap.clear();
+ sleepSetMap.clear();
+ choiceListStartIndexMap.clear();
+ }
+ }
+
+ @Override
+ public void stateRestored(Search search) {
+ if (debugMode) {
+ id = search.getStateId();
+ depth = search.getDepth();
+ transition = search.getTransition();
+ detail = null;
+ out.println("\n==> DEBUG: The state is restored to state with id: " + id + " -- Transition: " + transition +
+ " and depth: " + depth + "\n");
+ }
+ }
+
+ //--- the ones we are interested in
+ @Override
+ public void searchStarted(Search search) {
+ if (debugMode) {
+ out.println("\n==> DEBUG: ----------------------------------- search started" + "\n");
+ }
+ }
+
+ @Override
+ public void choiceGeneratorRegistered (VM vm, ChoiceGenerator<?> nextCG, ThreadInfo currentThread, Instruction executedInstruction) {
+ if (stateReductionMode) {
+ // Initialize with necessary information from the CG
+ if (nextCG instanceof IntChoiceFromSet) {
+ IntChoiceFromSet icsCG = (IntChoiceFromSet) nextCG;
+ // Check if CG has been initialized, otherwise initialize it
+ Integer[] cgChoices = icsCG.getAllChoices();
+ if (!isInitialized) {
+ // Get the upper bound from the last element of the choices
+ choiceUpperBound = cgChoices[cgChoices.length - 1];
+ isInitialized = true;
+ }
+ // Record the subsequent Integer CGs only until we hit the upper bound
+ if (!isResetAfterAnalysis && choiceCounter <= choiceUpperBound && !cgMap.containsValue(choiceCounter)) {
+ // Update the choices of the first CG and add '-1'
+ if (choices == null) {
+ // All the choices are always the same so we only need to update it once
+ choices = new Integer[cgChoices.length + 1];
+ System.arraycopy(cgChoices, 0, choices, 0, cgChoices.length);
+ choices[choices.length - 1] = -1;
+ }
+ icsCG.setNewValues(choices);
+ icsCG.reset();
+ // Advance the current Integer CG
+ // This way we explore all the event numbers in the first pass
+ icsCG.advance(choices[choiceCounter]);
+ cgMap.put(icsCG, choices[choiceCounter]);
+ choiceCounter++;
+ } else {
+ // Set done the subsequent CGs
+ // We only need n CGs (n is event numbers)
+ icsCG.setDone();
+ }
+ }
+ }
+ }
+
+ private void generateSleepSets() {
+
+ // Check and put the number into the sleep set if there is no conflict between the two
+ for (int i=0; i<=choiceUpperBound; i++) {
+ HashSet<Integer> sleepSet = new HashSet<>();
+ sleepSetMap.put(i,sleepSet);
+ for (int j=0; j<=choiceUpperBound; j++) {
+ if (i != j ) {
+ // Scour the data structure to find conflict
+ HashSet<Integer> conflictSet = new HashSet<>();
+ HashSet<Integer> reversedConflictSet = new HashSet<>();
+ if (conflictPairMap.containsKey(i)) {
+ conflictSet = conflictPairMap.get(i);
+ }
+ // Scour the reversed conflict mapper as well
+ if (conflictPairReversedMap.containsKey(i)) {
+ reversedConflictSet = conflictPairReversedMap.get(i);
+ }
+ if (!conflictSet.contains(j) && !reversedConflictSet.contains(j)) {
+ sleepSet.add(j);
+ }
+ }
+ }
+ }
+ }
+
+ private int getChoiceIndex(int event) {
+ for(int i=0; i<choices.length-1; i++) {
+ if (choices[i] == event) {
+ return i;
+ }
+ }
+ // Return -1 if not found
+ return -1;
+ }
+
+ private void generateBacktrackSets() {
+ int end = !isResetAfterAnalysis ? 0 : choiceListStartIndexMap.get(choices);
+ for(Integer currentChoice : conflictPairMap.keySet()) {
+ HashSet<Integer> conflictSet = conflictPairMap.get(currentChoice);
+ for(Integer eventNumber : conflictSet) {
+ // Both indices have to be greater than or equal to "end" index
+ // We don't want to repeat the same sequence
+ if (getChoiceIndex(currentChoice) >= end && getChoiceIndex(eventNumber) >= end) {
+ createBacktrackChoiceList(currentChoice, eventNumber);
+ }
+ }
+ }
+ }
+
+ private void resetAllCGs() {
+ // Extract the event numbers that have backtrack lists
+ Set<Integer> eventSet = backtrackMap.keySet();
+ // Return if there is no conflict at all (highly unlikely)
+ if (eventSet.isEmpty()) {
+ return;
+ }
+ // Reset every CG with the first backtrack lists
+ for(IntChoiceFromSet cg : cgMap.keySet()) {
+ int event = cgMap.get(cg);
+ LinkedList<Integer[]> choiceLists = backtrackMap.get(event);
+ if (choiceLists != null && choiceLists.peekFirst() != null) {
+ Integer[] choiceList = choiceLists.removeFirst();
+ // Deploy the new choice list for this CG
+ cg.setNewValues(choiceList);
+ cg.reset();
+ } else {
+ cg.setDone();
+ }
+ }
+ }
+
+ @Override
+ public void choiceGeneratorAdvanced (VM vm, ChoiceGenerator<?> currentCG) {
+
+ 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();
+ }
+ }
+ // Check every choice generated and make sure that all the available choices
+ // are chosen first before repeating the same choice of value twice!
+ if (currentCG instanceof IntChoiceFromSet) {
+ IntChoiceFromSet icsCG = (IntChoiceFromSet) currentCG;
+ // Update the current pointer to the current set of choices
+ if (choices == null || choices != icsCG.getAllChoices()) {
+ choiceListStartIndexMap.remove(choices);
+ currCG = icsCG;
+ choices = icsCG.getAllChoices();
+ }
+ // Traverse the sub-graphs
+ if (isResetAfterAnalysis) {
+ // Do this for every CG after finishing each backtrack list
+ if (icsCG.getNextChoice() == -1) {
+ int event = cgMap.get(icsCG);
+ LinkedList<Integer[]> choiceLists = backtrackMap.get(event);
+ if (choiceLists != null && choiceLists.peekFirst() != null) {
+ // Generate backtrack sets from this choiceList
+ generateBacktrackSets();
+ Integer[] choiceList = choiceLists.removeFirst();
+ // Deploy the new choice list for this CG
+ icsCG.setNewValues(choiceList);
+ icsCG.reset();
+ } else {
+ // Set done if this was the last backtrack list
+ icsCG.setDone();
+ }
+ }
+ }
+ // Update and reset the CG if needed (do this for the first time after the analysis)
+ if (!isResetAfterAnalysis && icsCG.getNextChoice() == -1) {
+ generateSleepSets();
+ generateBacktrackSets();
+ resetAllCGs();
+ isResetAfterAnalysis = true;
+ }
+ }
+ }
+ }
+
+ @Override
+ public void stateAdvanced(Search search) {
+ if (debugMode) {
+ id = search.getStateId();
+ depth = search.getDepth();
+ transition = search.getTransition();
+ if (search.isNewState()) {
+ detail = "new";
+ } else {
+ detail = "visited";
+ }
+
+ if (search.isEndState()) {
+ out.println("\n==> DEBUG: This is the last state!\n");
+ detail += " end";
+ }
+ out.println("\n==> DEBUG: The state is forwarded to state with id: " + id + " with depth: " + depth +
+ " which is " + detail + " Transition: " + transition + "\n");
+ }
+ }
+
+ @Override
+ public void stateBacktracked(Search search) {
+ if (debugMode) {
+ id = search.getStateId();
+ depth = search.getDepth();
+ transition = search.getTransition();
+ detail = null;
+
+ out.println("\n==> DEBUG: The state is backtracked to state with id: " + id + " -- Transition: " + transition +
+ " and depth: " + depth + "\n");
+ }
+ }
+
+ @Override
+ public void searchFinished(Search search) {
+ if (debugMode) {
+ out.println("\n==> DEBUG: ----------------------------------- search finished" + "\n");
+ }
+ }
+
+ // This class compactly stores Read and Write field sets
+ // We store the field name and its object ID
+ // Sharing the same field means the same field name and object ID
+ private class ReadWriteSet {
+ private HashMap<String,Integer> readSet;
+ private HashMap<String,Integer> writeSet;
+
+ public ReadWriteSet() {
+ readSet = new HashMap<>();
+ writeSet = new HashMap<>();
+ }
+
+ public void addReadField(String field, int objectId) {
+ readSet.put(field, objectId);
+ }
+
+ public void addWriteField(String field, int objectId) {
+ writeSet.put(field, objectId);
+ }
+
+ public boolean readFieldExists(String field) {
+ return readSet.containsKey(field);
+ }
+
+ public boolean writeFieldExists(String field) {
+ return writeSet.containsKey(field);
+ }
+
+ public int readFieldObjectId(String field) {
+ return readSet.get(field);
+ }
+
+ public int writeFieldObjectId(String field) {
+ return writeSet.get(field);
+ }
+ }
+
+ private void analyzeReadWriteAccesses(Instruction executedInsn, String fieldClass, int currentChoice) {
+ // Do the analysis to get Read and Write accesses to fields
+ ReadWriteSet rwSet;
+ // We already have an entry
+ if (readWriteFieldsMap.containsKey(choices[currentChoice])) {
+ rwSet = readWriteFieldsMap.get(choices[currentChoice]);
+ } else { // We need to create a new entry
+ rwSet = new ReadWriteSet();
+ readWriteFieldsMap.put(choices[currentChoice], rwSet);
+ }
+ int objectId = ((JVMFieldInstruction) executedInsn).getFieldInfo().getClassInfo().getClassObjectRef();
+ // Record the field in the map
+ if (executedInsn instanceof WriteInstruction) {
+ // Exclude certain field writes because of infrastructure needs, e.g., Event class field writes
+ for(String str : EXCLUDED_FIELDS_WRITE_INSTRUCTIONS_STARTS_WITH_LIST) {
+ if (fieldClass.startsWith(str)) {
+ return;
+ }
+ }
+ rwSet.addWriteField(fieldClass, objectId);
+ } else if (executedInsn instanceof ReadInstruction) {
+ rwSet.addReadField(fieldClass, objectId);
+ }
+ }
+
+ private boolean recordConflictPair(HashMap<Integer,HashSet<Integer>> confPairMap, int currentEvent, int eventNumber) {
+ HashSet<Integer> conflictSet;
+ if (!confPairMap.containsKey(currentEvent)) {
+ conflictSet = new HashSet<>();
+ confPairMap.put(currentEvent, conflictSet);
+ } else {
+ conflictSet = confPairMap.get(currentEvent);
+ }
+ // If this conflict has been recorded before, we return false because
+ // we don't want to service this backtrack point twice
+ if (conflictSet.contains(eventNumber)) {
+ return false;
+ }
+ // If it hasn't been recorded, then do otherwise
+ conflictSet.add(eventNumber);
+ return true;
+ }
+
+ private Integer[] copyIntegerListToArray(List<Integer> list) {
+ Integer[] integerArray = new Integer[list.size()];
+ for (int i=0; i<list.size(); i++) {
+ integerArray[i] = list.get(i);
+ }
+ return integerArray;
+ }
+
+ private void createBacktrackChoiceList(int currentChoice, int conflictEventNumber) {
+
+ LinkedList<Integer[]> backtrackChoiceLists;
+ // Create a new list of choices for backtrack based on the current choice and conflicting event number
+ // If we have a conflict between 1 and 3, then we create the list {3, 1, 2, 4, 5} for backtrack
+ // The backtrack point is the CG for event number 1 and the list length is one less than the original list
+ // since we don't start from event number 0
+ if (!isResetAfterAnalysis) {
+ // Check if we have a list for this choice number
+ // If not we create a new one for it
+ if (!backtrackMap.containsKey(conflictEventNumber)) {
+ backtrackChoiceLists = new LinkedList<>();
+ backtrackMap.put(conflictEventNumber, backtrackChoiceLists);
+ } else {
+ backtrackChoiceLists = backtrackMap.get(conflictEventNumber);
+ }
+ List<Integer> newChoiceList = new ArrayList<>();
+ // Put the conflicting event numbers first and reverse the order
+ newChoiceList.add(choices[currentChoice]);
+ newChoiceList.add(choices[conflictEventNumber]);
+ // Put the rest of the event numbers into the array starting from the minimum to the upper bound
+ for (int i = conflictEventNumber + 1; i < choices.length - 1; i++) {
+ // Check the sleep sets for excepted events that do not conflict with the current one
+ int prevSleepSet = newChoiceList.get(newChoiceList.size()-1);
+ HashSet<Integer> sleepSet = sleepSetMap.get(prevSleepSet);
+ if (choices[i] != choices[currentChoice] && !sleepSet.contains(choices[i])) {
+ newChoiceList.add(choices[i]);
+ }
+ }
+ // Set the last element to '-1' as the end of the sequence
+ newChoiceList.add(-1);
+ Integer[] newChoiceArray = copyIntegerListToArray(newChoiceList);
+ backtrackChoiceLists.addLast(newChoiceArray);
+ // The start index for the recursion is always 1 (from the main branch)
+ choiceListStartIndexMap.put(newChoiceArray, 1);
+ } else { // This is a sub-graph
+ int backtrackListIndex = cgMap.get(currCG);
+ backtrackChoiceLists = backtrackMap.get(backtrackListIndex);
+ List<Integer> newChoiceList = new ArrayList<>();
+ // Copy everything before the conflict number
+ int conflictEventCurrentIndex = getChoiceIndex(conflictEventNumber);
+ for(int i = 0; i < conflictEventCurrentIndex; i++) {
+ newChoiceList.add(choices[i]);
+ }
+ // Put the conflicting events
+ int currentChoiceCurrentIndex = getChoiceIndex(currentChoice);
+ newChoiceList.add(choices[currentChoiceCurrentIndex]);
+ newChoiceList.add(choices[conflictEventCurrentIndex]);
+ // Copy the rest
+ for(int i = conflictEventCurrentIndex + 1; i < choices.length - 1; i++) {
+ // Check the sleep sets for excepted events that do not conflict with the current one
+ int prevSleepSet = newChoiceList.get(newChoiceList.size()-1);
+ HashSet<Integer> sleepSet = sleepSetMap.get(prevSleepSet);
+ if (choices[i] != choices[currentChoiceCurrentIndex] && !sleepSet.contains(choices[i])) {
+ newChoiceList.add(choices[i]);
+ }
+ }
+ // Set the last element to '-1' as the end of the sequence
+ newChoiceList.add(-1);
+ Integer[] newChoiceArray = copyIntegerListToArray(newChoiceList);
+ backtrackChoiceLists.addLast(newChoiceArray);
+ // For the sub-graph the start index depends on the conflicting event number
+ choiceListStartIndexMap.put(newChoiceArray, conflictEventCurrentIndex + 1);
+ }
+ }
+
+ // We exclude fields that come from libraries (Java and Groovy), and also the infrastructure
+ private final static String[] EXCLUDED_FIELDS_STARTS_WITH_LIST =
+ // Java and Groovy libraries
+ { "java", "org", "sun", "com", "gov", "groovy"};
+ private final static String[] EXCLUDED_FIELDS_ENDS_WITH_LIST =
+ // Groovy library created fields
+ {"stMC", "callSiteArray", "metaClass", "staticClassInfo", "__constructor__",
+ // Infrastructure
+ "sendEvent", "Object", "reference", "location", "app", "state", "log", "functionList", "objectList",
+ "eventList", "valueList", "settings", "printToConsole", "app1", "app2"};
+ private final static String[] EXCLUDED_FIELDS_CONTAINS_LIST = {"_closure"};
+ private final static String[] EXCLUDED_FIELDS_WRITE_INSTRUCTIONS_STARTS_WITH_LIST = {"Event"};
+
+ private boolean isFieldExcluded(String field) {
+ // Check against "starts-with" list
+ for(String str : EXCLUDED_FIELDS_STARTS_WITH_LIST) {
+ if (field.startsWith(str)) {
+ return true;
+ }
+ }
+ // Check against "ends-with" list
+ for(String str : EXCLUDED_FIELDS_ENDS_WITH_LIST) {
+ if (field.endsWith(str)) {
+ return true;
+ }
+ }
+ // Check against "contains" list
+ for(String str : EXCLUDED_FIELDS_CONTAINS_LIST) {
+ if (field.contains(str)) {
+ return true;
+ }
+ }
+
+ return false;
+ }
+
+ @Override
+ public void instructionExecuted(VM vm, ThreadInfo ti, Instruction nextInsn, Instruction executedInsn) {
+ if (stateReductionMode) {
+ if (isInitialized && !isResetAfterAnalysis) {
+ if (choiceCounter > choices.length - 1) {
+ // We do not compute the conflicts for the choice '-1'
+ return;
+ }
+ int currentChoice = choiceCounter - 1;
+ // Record accesses from executed instructions
+ if (executedInsn instanceof JVMFieldInstruction) {
+ // Analyze only after being initialized
+ String fieldClass = ((JVMFieldInstruction) executedInsn).getFieldInfo().getFullName();
+ // We don't care about libraries
+ if (!isFieldExcluded(fieldClass)) {
+ analyzeReadWriteAccesses(executedInsn, fieldClass, currentChoice);
+ }
+ }
+ // Analyze conflicts from next instructions
+ if (nextInsn instanceof JVMFieldInstruction) {
+ // The constructor is only called once when the object is initialized
+ // It does not have shared access with other objects
+ MethodInfo mi = nextInsn.getMethodInfo();
+ if (!mi.getName().equals("<init>")) {
+ String fieldClass = ((JVMFieldInstruction) nextInsn).getFieldInfo().getFullName();
+ // We don't care about libraries
+ if (!isFieldExcluded(fieldClass)) {
+ // For the main graph we go down to 0, but for subgraph, we only go down to 1 since 0 contains
+ // the reversed event
+ // Check for conflict (go backward from currentChoice and get the first conflict)
+ // If the current event has conflicts with multiple events, then these will be detected
+ // one by one as this recursively checks backward when backtrack set is revisited and executed.
+ for (int eventNumber = currentChoice - 1; eventNumber >= 0; eventNumber--) {
+ // Skip if this event number does not have any Read/Write set
+ if (!readWriteFieldsMap.containsKey(choices[eventNumber])) {
+ continue;
+ }
+ ReadWriteSet rwSet = readWriteFieldsMap.get(choices[eventNumber]);
+ int currObjId = ((JVMFieldInstruction) nextInsn).getFieldInfo().getClassInfo().getClassObjectRef();
+ // 1) Check for conflicts with Write fields for both Read and Write instructions
+ if (((nextInsn instanceof WriteInstruction || nextInsn instanceof ReadInstruction) &&
+ rwSet.writeFieldExists(fieldClass) && rwSet.writeFieldObjectId(fieldClass) == currObjId) ||
+ (nextInsn instanceof WriteInstruction && rwSet.readFieldExists(fieldClass) &&
+ rwSet.readFieldObjectId(fieldClass) == currObjId)) {
+ // We do not record and service the same backtrack pair/point twice!
+ // If it has been serviced before, we just skip this
+ if (recordConflictPair(conflictPairMap, currentChoice, eventNumber)) {
+ recordConflictPair(conflictPairReversedMap, eventNumber, currentChoice);
+ // Break if a conflict is found!
+ break;
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+}
projects / jpf-core.git / commitdiff