예제 #1
0
 /**
  * Instantiates a new CPA algorithm with a backward location analysis, a default backward
  * transformer factory and worklist suitable for an analysis of a complete and already
  * reconstructed control flow automaton.
  *
  * @param program The program object
  * @param cpas The list of backward analyses to be performed
  */
 public static CPAAlgorithm createBackwardAlgorithm(
     Program program, ConfigurableProgramAnalysis... cpas) {
   ConfigurableProgramAnalysis cpa =
       new CompositeProgramAnalysis(new BackwardLocationAnalysis(), cpas);
   return new CPAAlgorithm(
       program,
       cpa,
       new ReverseCFATransformerFactory(program.getCFA()),
       new FastSet<AbstractState>());
 }
예제 #2
0
  @Override
  public void run() {
    Runtime runtime = Runtime.getRuntime();
    // Jakstab Algorithm
    System.out.println("Starting CPA algorithm.");
    AbstractState start = cpa.initStartState(transformerFactory.getInitialLocation());
    worklist.add(start);
    reached.add(start);
    if (art != null) art.setRoot(start);

    // Set up precisions
    Precision precision = cpa.initPrecision(transformerFactory.getInitialLocation(), null);
    Map<Location, Precision> precisionMap = new HashMap<Location, Precision>();
    precisionMap.put(start.getLocation(), precision);

    int steps = 0;
    statesVisited = 0;
    final int stepThreshold = 1000;
    long startTime = System.currentTimeMillis();
    long lastSteps = 0;
    long lastTime = 0;
    while (!worklist.isEmpty() && !stop && (!failFast || isSound())) {

      statesVisited++;
      if (++steps == stepThreshold) {

        // Helps limit memory usage
        long now = System.currentTimeMillis();
        System.gc();
        long gcTime = System.currentTimeMillis() - now;
        logger.debug("Time for GC: " + gcTime + "ms");

        now = System.currentTimeMillis();
        long duration = Math.max(1, now - lastTime);
        long speed = (1000L * (statesVisited - lastSteps) / duration);
        // speed = Math.min(speed, 1000);

        logger.warn(
            "*** Reached "
                + reached.size()
                + " states, processed "
                + statesVisited
                + " states after "
                + (now - startTime)
                + "ms, at "
                + speed
                + " states/second"
                + (transformerFactory instanceof ResolvingTransformerFactory
                    ? ", " + program.getInstructionCount() + " instructions."
                    : "."));

        logger.info(
            String.format(
                "    Allocated heap memory: %.2f MByte",
                (runtime.totalMemory() - runtime.freeMemory()) / (1024.0 * 1024.0)));

        steps = 0;

        // StatsPlotter.plot((now - startTime) + "\t" + statesVisited
        // +"\t" + program.getInstructionCount() + "\t" + gcTime + "\t"
        // + speed);

        lastSteps = statesVisited;
        lastTime = now;

        if (Options.timeout.getValue() > 0
            && (System.currentTimeMillis() - startTime > Options.timeout.getValue() * 1000)) {
          logger.error("Timeout after " + Options.timeout.getValue() + "s!");
          stop = true;
        }
      }

      // We need the state before precision refinement for building the
      // ART
      AbstractState unadjustedState = worklist.pick();

      /*
       * if (unadjustedState.getLocation().getAddress().toString().equals(
       * "0x00401189") //||
       * unadjustedState.getLocation().getAddress().toString
       * ().equals("0x0040119b") ||
       * unadjustedState.getLocation().getAddress
       * ().toString().equals("0x00401078") ||
       * unadjustedState.getLocation(
       * ).getAddress().toString().equals("0x0040100a") )
       * System.out.println("Debug " +
       * unadjustedState.getLocation().getAddress().toString());
       */

      precision = precisionMap.get(unadjustedState.getLocation());

      Pair<AbstractState, Precision> pair = cpa.prec(unadjustedState, precision, reached);

      // Warning: The refined a is not stored in "reached", only used for
      // successor calculation
      AbstractState a = pair.getLeft();

      /*
       * CompositeState a1 = (CompositeState) a; BasedNumberValuation a2 =
       * (BasedNumberValuation)a1.getComponent(1); if
       * (a2.getStore().isTop()) System.out.println("Debug TOP Value");
       */

      precision = pair.getRight();
      precisionMap.put(a.getLocation(), precision);

      // logger.debug("Picked from worklist: " + a.getIdentifier());

      // getTransformers() and post() might throw exceptions
      try {
        // For each outgoing edge
        // if (a.isTop())
        // System.out.println("Debug TOP");

        /*
         * if
         * (a.getLocation().getAddress().toString().equals("0x004106cd")
         * ||
         * (a.getLocation().getAddress().toString().equals("0x00410498")
         * && a.getLocation().getIndex() >= 0))
         * System.out.println("Debug Transformer Factory:" +
         * a.getLocation().getAddress().toString());
         */

        // Set<CFAEdge> s = transformerFactory.getTransformers(a);
        // System.out.println("Debug Transformer Factory:" +
        // a.getLocation().getAddress().toString());
        for (CFAEdge cfaEdge : transformerFactory.getTransformers(a)) {

          Precision targetPrecision = precisionMap.get(cfaEdge.getTarget());
          if (targetPrecision == null) {
            targetPrecision = cpa.initPrecision(cfaEdge.getTarget(), cfaEdge.getTransformer());
            precisionMap.put(cfaEdge.getTarget(), targetPrecision);
          }

          // Prefix everything by current location for easier
          // debugging
          // Logger.setGlobalPrefix(cfaEdge.getSource().toString());
          // if
          // (cfaEdge.getSource().getAddress().toString().equals("0x00401027")
          // &&
          // cfaEdge.getTarget().getAddress().toString().equals("0x0040102e"))
          // System.out.println("Debug Edge");
          // Calculate the set of abstract successors
          Set<AbstractState> successors = cpa.post(a, cfaEdge, targetPrecision);

          if (successors.isEmpty()) {
            logger.debug("No successors along edge " + cfaEdge + ", reached halt?");
            continue;
          }

          // logger.debug("via edge " + cfaEdge.toString() + " " +
          // successors.size() + " successors.");

          // Process every successor
          for (AbstractState succ : successors) {
            // logger.debug("Processing new post state: " +
            // succ.getIdentifier());

            // Try to merge the new state with an existing one
            Set<AbstractState> statesToRemove = new FastSet<AbstractState>();
            Set<AbstractState> statesToAdd = new FastSet<AbstractState>();

            for (AbstractState r : reached.where(0, ((CompositeState) succ).getComponent(0))) {
              AbstractState merged = cpa.merge(succ, r, targetPrecision);
              if (!merged.equals(r)) {
                // logger.debug("Merge of " +
                // succ.getIdentifier() + " and " +
                // r.getIdentifier() + " produced new state " +
                // merged.getIdentifier());
                statesToRemove.add(r);
                statesToAdd.add(merged);
              }
            }

            // replace the old state in worklist and reached with
            // the merged version
            for (AbstractState r : statesToRemove) {
              reached.remove(r);
              worklist.remove(r);
              // art.remove(r);
            }

            for (AbstractState r : statesToAdd) {
              // Only add r to the worklist if it hasn't been
              // reached yet
              if (reached.add(r)) {
                worklist.add(r);
                if (art != null) art.addChild(unadjustedState, r);
              }
            }

            // if not stopped add to worklist
            if (!cpa.stop(succ, reached, targetPrecision)
                || this.program.checkSMPos(((CompositeState) succ).getLocation().getAddress())) {
              worklist.add(succ);
              reached.add(succ);
              if (art != null) art.addChild(unadjustedState, succ);
            }
          }
          // end for each outgoing edge
        }
      } catch (StateException e) {
        if (e.getState() == null) {
          e.setState(a);
        }
        if (art != null && !unadjustedState.equals(e.getState()))
          art.addChild(unadjustedState, e.getState());
        throw e;
      }
    }
    long endTime = System.currentTimeMillis();
    if (endTime - startTime > 0) {
      logger.info(
          "Processed "
              + statesVisited
              + " states at "
              + (1000L * statesVisited / (endTime - startTime))
              + " states/second");
      logger.info(
          String.format(
              "Allocated heap memory: %.2f MByte",
              (runtime.totalMemory() - runtime.freeMemory()) / (1024.0 * 1024.0)));
    }

    completed = worklist.isEmpty();
  }