*/
package gov.nasa.jpf.listener;
+import com.sun.org.apache.xpath.internal.operations.Bool;
import gov.nasa.jpf.Config;
import gov.nasa.jpf.JPF;
import gov.nasa.jpf.ListenerAdapter;
import gov.nasa.jpf.vm.bytecode.ReadInstruction;
import gov.nasa.jpf.vm.bytecode.StoreInstruction;
import gov.nasa.jpf.vm.bytecode.WriteInstruction;
+import gov.nasa.jpf.vm.choice.IntChoiceFromSet;
import gov.nasa.jpf.vm.choice.IntIntervalGenerator;
+import java.awt.*;
import java.io.PrintWriter;
import java.util.*;
+import java.util.List;
// TODO: Fix for Groovy's model-checking
-// TODO: This is a listener created to detect device conflicts and global variable conflicts
+// TODO: This is a setter to change the values of the ChoiceGenerator to implement POR
/**
- * Simple listener tool to track remove unwanted ChoiceGenerators that are registered
- * while an existing ChoiceGenerator is being explored. Multiple ChoiceGenerators of the same
- * type could be registered spuriously during a while(true) loop.
+ * simple tool to log state changes
*/
public class StateReducer extends ListenerAdapter {
+ // Debug info fields
private boolean debugMode;
private boolean stateReductionMode;
private final PrintWriter out;
- private String detail;
- private int depth;
- private int id;
- private Transition transition;
- private HashSet<String> conflictSet;
- private HashSet<String> appSet;
- // Holds the event value numbers that execute write instructions
- private HashSet<Integer> writeEventNumberSet;
- // Holds values that have appeared during CG advances
- private HashSet<Integer> cgChoiceSet;
+ volatile private String detail;
+ volatile private int depth;
+ volatile private int id;
+ Transition transition;
+
+ // State reduction fields
+ private int choiceCounter;
private Integer choiceUpperBound;
private boolean isInitialized;
- private int currentChoice;
- // Records how many times BooleanChoiceGenerator has been advanced
- private int bCGIsAdvanced;
- // Records how many times we have looped through all the event numbers (IntIntervalGenerator)
- private int iiCGIsLooped;
-
- // Constants to determine when to start reducing states
- private final int BOOLEAN_CG_ADVANCED_THRESHOLD = 2;
- private final int INTEGER_CG_ADVANCED_THRESHOLD = 50;
+ private boolean isResetAfterAnalysis;
+ private boolean isBooleanCGFlipped;
+ private HashMap<IntChoiceFromSet,Integer> cgMap;
+ // Record the mapping between event number and field accesses (Read and Write)
+ private HashMap<Integer,ReadWriteSet> readWriteFieldsMap;
+ // 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;
+ private HashMap<Integer,HashSet<Integer>> conflictPairMap;
- public StateReducer (Config config) {
+ public StateReducer (Config config, JPF jpf) {
debugMode = config.getBoolean("debug_state_transition", false);
stateReductionMode = config.getBoolean("activate_state_reduction", true);
if (debugMode) {
depth = 0;
id = 0;
transition = null;
- cgChoiceSet = new HashSet<>();
- choiceUpperBound = 0;
- isInitialized = false;
- conflictSet = new HashSet<>();
- String[] conflictVars = config.getStringArray("variables");
- // We are not tracking anything if it is null
- if (conflictVars != null) {
- for (String var : conflictVars) {
- conflictSet.add(var);
- }
- }
- appSet = new HashSet<>();
- String[] apps = config.getStringArray("apps");
- // We are not tracking anything if it is null
- if (apps != null) {
- for (String var : apps) {
- appSet.add(var);
- }
+ isBooleanCGFlipped = false;
+ initializeStateReduction();
+ }
+
+ private void initializeStateReduction() {
+ if (stateReductionMode) {
+ choiceCounter = 0;
+ choiceUpperBound = 0;
+ isInitialized = false;
+ isResetAfterAnalysis = false;
+ cgMap = new HashMap<>();
+ readWriteFieldsMap = new HashMap<>();
+ backtrackMap = new HashMap<>();
+ conflictPairMap = new HashMap<>();
}
- currentChoice = 0;
- writeEventNumberSet = new HashSet<>();
- bCGIsAdvanced = 0;
- iiCGIsLooped = 0;
}
@Override
}
@Override
- public void choiceGeneratorSet (VM vm, ChoiceGenerator<?> newCG) {
+ public void choiceGeneratorRegistered (VM vm, ChoiceGenerator<?> nextCG, ThreadInfo currentThread, Instruction executedInstruction) {
if (stateReductionMode) {
// Initialize with necessary information from the CG
- if (newCG instanceof IntIntervalGenerator) {
- IntIntervalGenerator iigCG = (IntIntervalGenerator) newCG;
+ if (nextCG instanceof IntChoiceFromSet) {
+ IntChoiceFromSet icsCG = (IntChoiceFromSet) nextCG;
// Check if CG has been initialized, otherwise initialize it
+ Object[] choices = icsCG.getAllChoices();
if (!isInitialized) {
- Integer[] choices = iigCG.getChoices();
// Get the upper bound from the last element of the choices
- choiceUpperBound = choices[choices.length - 1];
+ choiceUpperBound = (Integer) choices[choices.length - 1];
isInitialized = true;
+ }
+ // Record the subsequent Integer CGs only until we hit the upper bound
+ if (choiceCounter < choiceUpperBound && !cgMap.containsValue(choiceCounter)) {
+ // Update the choices of the first CG and add '-1'
+ Integer[] newChoices = new Integer[choices.length + 1];
+ System.arraycopy(choices, 0, newChoices, 0, choices.length);
+ newChoices[newChoices.length - 1] = -1;
+ icsCG.setNewValues(newChoices);
+ icsCG.reset();
+ // Advance the current Integer CG
+ // This way we explore all the event numbers in the first pass
+ icsCG.advance(choiceCounter);
+ cgMap.put(icsCG, choiceCounter);
+ choiceCounter++;
} else {
- newCG.setDone();
+ // Set done the subsequent CGs
+ // We only need n CGs (n is event numbers)
+ icsCG.setDone();
}
}
}
}
+ 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.peekFirst() != null) {
+ Integer[] choiceList = choiceLists.removeFirst();
+ // Deploy the new choice list for this CG
+ cg.setNewValues(choiceList);
+ cg.reset();
+ }
+ }
+ }
+
@Override
public void choiceGeneratorAdvanced (VM vm, ChoiceGenerator<?> currentCG) {
- if (stateReductionMode) {
- // Check for BooleanChoiceGenerator
+
+ if(stateReductionMode) {
+ // Check the boolean CG and if it is flipped, we are resetting the analysis
if (currentCG instanceof BooleanChoiceGenerator) {
- bCGIsAdvanced++;
+ 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 IntIntervalGenerator) {
- IntIntervalGenerator iigCG = (IntIntervalGenerator) currentCG;
- Integer nextChoice = iigCG.getNextChoice();
- if (!cgChoiceSet.contains(nextChoice)) {
- cgChoiceSet.add(nextChoice);
+ if (currentCG instanceof IntChoiceFromSet) {
+ IntChoiceFromSet icsCG = (IntChoiceFromSet) currentCG;
+ // Update and reset the CG if needed (do this for the first time after the analysis)
+ if (!isResetAfterAnalysis && icsCG.getNextChoice() == -1) {
+ resetAllCGs();
+ isResetAfterAnalysis = true;
}
- // Allow reinitialization after an upper bound is hit
- // This means all available choices have been explored once during this iteration
- if (cgChoiceSet.contains(choiceUpperBound)) {
- isInitialized = false;
- cgChoiceSet.clear();
- iiCGIsLooped++;
- }
- // Record the current choice
- currentChoice = iigCG.getNextChoice();
- // Start reducing (advancing) if the thresholds are passed
- if (iiCGIsLooped >= INTEGER_CG_ADVANCED_THRESHOLD &&
- bCGIsAdvanced >= BOOLEAN_CG_ADVANCED_THRESHOLD) {
- if (!writeEventNumberSet.contains(currentChoice)) {
- iigCG.advance();
+ // Do this for every CG after finishing each backtrack list
+ if (isResetAfterAnalysis && icsCG.getNextChoice() == -1) {
+ int event = cgMap.get(icsCG);
+ LinkedList<Integer[]> choiceLists = backtrackMap.get(event);
+ if (choiceLists.peekFirst() != null) {
+ 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();
}
}
}
}
}
- @Override
- public void instructionExecuted(VM vm, ThreadInfo ti, Instruction nextInsn, Instruction executedInsn) {
- // CASE #1: Detecting variable write-after-write conflict
+ // This class compactly stores Read and Write field sets
+ private class ReadWriteSet {
+ private HashSet<String> readSet;
+ private HashSet<String> writeSet;
+
+ public ReadWriteSet() {
+ readSet = new HashSet<>();
+ writeSet = new HashSet<>();
+ }
+
+ public void addReadField(String field) {
+ readSet.add(field);
+ }
+
+ public void addWriteField(String field) {
+ writeSet.add(field);
+ }
+
+ public boolean readFieldExists(String field) {
+ return readSet.contains(field);
+ }
+
+ public boolean writeFieldExists(String field) {
+ return writeSet.contains(field);
+ }
+ }
+
+ private void analyzeReadWriteAccesses(Instruction executedInsn, String fieldClass) {
+ // Do the analysis to get Read and Write accesses to fields
+ ReadWriteSet rwSet;
+ // We already have an entry
+ if (readWriteFieldsMap.containsKey(choiceCounter)) {
+ rwSet = readWriteFieldsMap.get(choiceCounter);
+ } else { // We need to create a new entry
+ rwSet = new ReadWriteSet();
+ readWriteFieldsMap.put(choiceCounter, rwSet);
+ }
+ // Record the field in the map
if (executedInsn instanceof WriteInstruction) {
- // Check for write-after-write conflict
- String varId = ((WriteInstruction) executedInsn).getFieldInfo().getFullName();
- for(String var : conflictSet) {
- if (varId.contains(var)) {
- String writer = getWriter(ti.getStack());
- // Just return if the writer is not one of the listed apps in the .jpf file
- if (writer == null)
- return;
+ rwSet.addWriteField(fieldClass);
+ }
+ if (executedInsn instanceof ReadInstruction) {
+ rwSet.addReadField(fieldClass);
+ }
+ }
- // Stores event number that executes WriteInstruction
- if (!writeEventNumberSet.contains(currentChoice)) {
- writeEventNumberSet.add(currentChoice);
- }
- }
+ private boolean recordConflictPair(int currentEvent, int eventNumber) {
+ HashSet<Integer> conflictSet;
+ if (!conflictPairMap.containsKey(currentEvent)) {
+ conflictSet = new HashSet<>();
+ conflictPairMap.put(currentEvent, conflictSet);
+ } else {
+ conflictSet = conflictPairMap.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 void createBacktrackChoiceList(int currentChoice, int conflictEventNumber) {
+
+ int minChoice = Math.min(currentChoice, conflictEventNumber);
+ int maxChoice = Math.max(currentChoice, conflictEventNumber);
+ LinkedList<Integer[]> backtrackChoiceLists;
+ // Check if we have a list for this choice number
+ // If not we create a new one for it
+ if (!backtrackMap.containsKey(minChoice)) {
+ backtrackChoiceLists = new LinkedList<>();
+ backtrackMap.put(minChoice, backtrackChoiceLists);
+ } else {
+ backtrackChoiceLists = backtrackMap.get(minChoice);
+ }
+ // TODO: The following might change depending on the POR implementation detail
+ // 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
+ // (originally of length 6) since we don't start from event number 0
+ int maxListLength = choiceUpperBound + 1;
+ int listLength = maxListLength - minChoice;
+ Integer[] choiceList = new Integer[listLength+1];
+ // Put the conflicting event numbers first and reverse the order
+ choiceList[0] = maxChoice;
+ choiceList[1] = minChoice;
+ // Put the rest of the event numbers into the array starting from the minimum to the upper bound
+ for(int i = minChoice + 1, j = 2; j < listLength; i++) {
+ if (i != maxChoice) {
+ choiceList[j] = i;
+ j++;
}
}
+ // Set the last element to '-1' as the end of the sequence
+ choiceList[choiceList.length - 1] = -1;
+ backtrackChoiceLists.addLast(choiceList);
}
- // Find the variable writer
- // It should be one of the apps listed in the .jpf file
- private String getWriter(List<StackFrame> sfList) {
- // Start looking from the top of the stack backward
- for(int i=sfList.size()-1; i>=0; i--) {
- MethodInfo mi = sfList.get(i).getMethodInfo();
- if(!mi.isJPFInternal()) {
- String method = mi.getStackTraceName();
- // Check against the apps in the appSet
- for(String app : appSet) {
- // There is only one writer at a time but we need to always
- // check all the potential writers in the list
- if (method.contains(app)) {
- return app;
+ @Override
+ public void instructionExecuted(VM vm, ThreadInfo ti, Instruction nextInsn, Instruction executedInsn) {
+ if (stateReductionMode) {
+ // Record accesses from executed instructions
+ if (executedInsn instanceof JVMFieldInstruction) {
+ String fieldClass = ((JVMFieldInstruction) executedInsn).getFieldInfo().getFullName();
+ // We don't care about libraries
+ if (!fieldClass.startsWith("java") &&
+ !fieldClass.startsWith("org") &&
+ !fieldClass.startsWith("sun") &&
+ !fieldClass.startsWith("com") &&
+ !fieldClass.startsWith("gov") &&
+ !fieldClass.startsWith("groovy")) {
+ analyzeReadWriteAccesses(executedInsn, fieldClass);
+ }
+ }
+ // Analyze conflicts from next instructions
+ if (nextInsn instanceof JVMFieldInstruction) {
+ String fieldClass = ((JVMFieldInstruction) nextInsn).getFieldInfo().getFullName();
+ // We don't care about libraries
+ if (!fieldClass.startsWith("java") &&
+ !fieldClass.startsWith("org") &&
+ !fieldClass.startsWith("sun") &&
+ !fieldClass.startsWith("com") &&
+ !fieldClass.startsWith("gov") &&
+ !fieldClass.startsWith("groovy")) {
+ // 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=choiceCounter-1; eventNumber>=0; eventNumber--) {
+ // Skip if this event number does not have any Read/Write set
+ if (!readWriteFieldsMap.containsKey(eventNumber)) {
+ continue;
+ }
+ ReadWriteSet rwSet = readWriteFieldsMap.get(eventNumber);
+ // 1) Check for conflicts with Write fields for both Read and Write instructions
+ // 2) Check for conflicts with Read fields for Write instructions
+ if (((nextInsn instanceof WriteInstruction || nextInsn instanceof ReadInstruction) &&
+ rwSet.writeFieldExists(fieldClass)) ||
+ (nextInsn instanceof WriteInstruction && rwSet.readFieldExists(fieldClass))) {
+ // We do not record and service the same backtrack pair/point twice!
+ // If it has been serviced before, we just skip this
+ if (recordConflictPair(choiceCounter, eventNumber)) {
+ createBacktrackChoiceList(choiceCounter, eventNumber);
+ // Break if a conflict is found!
+ break;
+ }
+ }
}
}
}
}
-
- return null;
}
}
\ No newline at end of file
projects / jpf-core.git / commitdiff