Checking in (1) StateReducer, and (2) StateReducerEfficient; ISSUE: the StateReducerE...
authorrtrimana <rtrimana@uci.edu>
Tue, 12 Nov 2019 21:32:02 +0000 (13:32 -0800)
committerrtrimana <rtrimana@uci.edu>
Tue, 12 Nov 2019 21:32:02 +0000 (13:32 -0800)
src/main/gov/nasa/jpf/listener/StateReducer.java
src/main/gov/nasa/jpf/listener/StateReducerEfficient.java [new file with mode: 0644]

index 08b27b1..4667668 100644 (file)
@@ -509,4 +509,4 @@ public class StateReducer extends ListenerAdapter {
       }
     }
   }
-}
\ No newline at end of file
+}
diff --git a/src/main/gov/nasa/jpf/listener/StateReducerEfficient.java b/src/main/gov/nasa/jpf/listener/StateReducerEfficient.java
new file mode 100644 (file)
index 0000000..ebe9201
--- /dev/null
@@ -0,0 +1,529 @@
+/*
+ * 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: ISSUES
+// TODO: This POR implementation, however, has some issues in that the DFS algorithm doesn't properly
+//       traverse the sub-graphs after resets (the CGs are ignored)
+/**
+ * simple tool to log state changes
+ */
+public class StateReducerEfficient 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 HashMap<IntChoiceFromSet,Boolean> resetAfterAnalysisMap;
+  private HashMap<IntChoiceFromSet,Integer[]> cgToParentChoicesMap;
+  private HashMap<Integer[],HashMap<IntChoiceFromSet,Integer>> choicesToCGMap;
+  private HashMap<Integer[],HashMap<Integer,LinkedList<Integer[]>>> choicesToBacktrackMap;
+  private boolean isBooleanCGFlipped;
+  // 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,HashSet<Integer>> conflictPairMap;
+
+  public StateReducerEfficient (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;
+    // TODO: TESTING
+    choicesToCGMap = new HashMap<>();
+    choicesToBacktrackMap = new HashMap<>();
+    resetAfterAnalysisMap = new HashMap<>();
+    resetAfterAnalysisMap.put(null, false);
+    cgToParentChoicesMap = new HashMap<>();
+    readWriteFieldsMap = new HashMap<>();
+    conflictPairMap = new HashMap<>();
+    choices = null;
+    currCG = null;
+    choiceCounter = 0;
+    initializeStateReduction();
+  }
+
+  private void initializeStateReduction() {
+    choiceUpperBound = 0;
+    isInitialized = false;
+    readWriteFieldsMap.clear();
+    conflictPairMap.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");
+    }
+  }
+
+  // We map current child CG to parent CG
+  private void insertCGToMap(int choice, IntChoiceFromSet childCG) {
+    HashMap<IntChoiceFromSet,Integer> cgMap;
+    if (choicesToCGMap.containsKey(choices)) {
+      cgMap = choicesToCGMap.get(choices);
+    } else {
+      cgMap = new HashMap<>();
+    }
+    cgMap.put(childCG, choice);
+    choicesToCGMap.put(choices,cgMap);
+  }
+
+  @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 = null;
+        if (!isInitialized) {
+          if (currCG == null) { // Main
+            cgChoices = icsCG.getAllChoices();
+            // Get the upper bound from the last element of the choices
+            choiceUpperBound = cgChoices.length - 1;
+          } else { // Sub-graph
+            cgChoices = choices;
+            choiceUpperBound = cgChoices.length - 2;
+          }
+          isInitialized = true;
+        }
+        // Record the subsequent Integer CGs only until we hit the upper bound
+        boolean isResetAfterAnalysis = resetAfterAnalysisMap.get(currCG);
+        if (!isResetAfterAnalysis && choiceCounter <= choiceUpperBound) {
+          // 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]);
+          insertCGToMap(choices[choiceCounter], icsCG);
+          choiceCounter++;
+          cgToParentChoicesMap.put(icsCG, choices);
+        } else {
+          // Set done the subsequent CGs
+          // We only need n CGs (n is event numbers)
+          icsCG.setDone();
+        }
+      }
+    }
+  }
+
+  private void resetAllCGs() {
+    HashMap<Integer,LinkedList<Integer[]>> currBacktrackMap = choicesToBacktrackMap.get(choices);
+    if (currBacktrackMap == null) {
+      return;
+    }
+    // Extract the event numbers that have backtrack lists
+    Set<Integer> eventSet = currBacktrackMap.keySet();
+    // Return if there is no conflict at all (highly unlikely)
+    if (eventSet.isEmpty()) {
+      return;
+    }
+    // Reset every CG with the first backtrack lists
+    HashMap<IntChoiceFromSet,Integer> currCGMap = choicesToCGMap.get(choices);
+    for(IntChoiceFromSet cg : currCGMap.keySet()) {
+      int event = currCGMap.get(cg);
+      LinkedList<Integer[]> choiceLists = currBacktrackMap.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 {
+          choiceCounter = 0;
+          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()) {
+          currCG = icsCG;
+          choices = icsCG.getAllChoices();
+          resetAfterAnalysisMap.put(icsCG, false);
+          choiceCounter = 1;
+          // Reset states for the sub-graph
+          initializeStateReduction();
+        }
+        if (icsCG.getNextChoice() == -1) {
+          // Get the current CG
+          boolean isCurrResetAfterAnalysis = resetAfterAnalysisMap.get(currCG);
+          // Update and reset the CG if needed (do this for the first time after the analysis)
+          if (!isCurrResetAfterAnalysis) {
+            resetAllCGs();
+            resetAfterAnalysisMap.put(currCG, true);
+          }
+          if (!icsCG.isDone()) {
+            // Get the CG that needs to be reset
+            Integer[] parentChoices = cgToParentChoicesMap.get(icsCG);
+            // Do this for every CG after finishing each backtrack list
+            HashMap<IntChoiceFromSet, Integer> parentCGMap = choicesToCGMap.get(parentChoices);
+            HashMap<Integer, LinkedList<Integer[]>> parentBacktrackMap = choicesToBacktrackMap.get(parentChoices);
+            int event = parentCGMap.get(icsCG);
+            LinkedList<Integer[]> choiceLists = parentBacktrackMap.get(event);
+            if (choiceLists != null && 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 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(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) {
+
+    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
+    // (originally of length 6) since we don't start from event number 0
+    boolean isResetAfterAnalysis = resetAfterAnalysisMap.get(currCG);
+    if (!isResetAfterAnalysis) {
+      HashMap<Integer,LinkedList<Integer[]>> currBacktrackMap;
+      if (!choicesToBacktrackMap.containsKey(choices)) {
+        currBacktrackMap = new HashMap<>();
+        choicesToBacktrackMap.put(choices, currBacktrackMap);
+      } else {
+        currBacktrackMap = choicesToBacktrackMap.get(choices);
+      }
+      // Check if we have a list for this choice number
+      // If not we create a new one for it
+      if (!currBacktrackMap.containsKey(conflictEventNumber)) {
+        backtrackChoiceLists = new LinkedList<>();
+        currBacktrackMap.put(conflictEventNumber, backtrackChoiceLists);
+      } else {
+        backtrackChoiceLists = currBacktrackMap.get(conflictEventNumber);
+      }
+      int maxListLength = choiceUpperBound + 1;
+      int listLength = maxListLength - conflictEventNumber;
+      Integer[] newChoiceList = new Integer[listLength + 1];
+      // Put the conflicting event numbers first and reverse the order
+      newChoiceList[0] = choices[currentChoice];
+      newChoiceList[1] = 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, j = 2; j < listLength; i++) {
+        if (choices[i] != choices[currentChoice]) {
+          newChoiceList[j] = choices[i];
+          j++;
+        }
+      }
+      // Set the last element to '-1' as the end of the sequence
+      newChoiceList[newChoiceList.length - 1] = -1;
+      backtrackChoiceLists.addLast(newChoiceList);
+    }
+  }
+
+  // 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) {
+        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
+              // If null then it is the main graph, if not it is a sub-graph
+              int end = currCG == null ? 0 : 1;
+              // 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 >= end; 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
+                // 2) Check for conflicts with Read fields for 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(currentChoice, eventNumber)) {
+                    createBacktrackChoiceList(currentChoice, eventNumber);
+                    // Break if a conflict is found!
+                    break;
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+}