/**
   * Traverse the statements in the given body, looking for aggregation possibilities; that is,
   * given a def d and a use u, d has no other uses, u has no other defs, collapse d and u.
   *
   * <p>option: only-stack-locals; if this is true, only aggregate variables starting with $
   */
  protected void internalTransform(Body b, String phaseName, Map<String, String> options) {
    StmtBody body = (StmtBody) b;
    boolean onlyStackVars = PhaseOptions.getBoolean(options, "only-stack-locals");

    int aggregateCount = 1;

    if (Options.v().time()) Timers.v().aggregationTimer.start();
    boolean changed = false;

    Map<ValueBox, Zone> boxToZone =
        new HashMap<ValueBox, Zone>(body.getUnits().size() * 2 + 1, 0.7f);

    // Determine the zone of every box
    {
      Zonation zonation = new Zonation(body);

      for (Unit u : body.getUnits()) {
        Zone zone = zonation.getZoneOf(u);

        for (ValueBox box : u.getUseBoxes()) {
          boxToZone.put(box, zone);
        }

        for (ValueBox box : u.getDefBoxes()) {
          boxToZone.put(box, zone);
        }
      }
    }

    do {
      if (Options.v().verbose())
        G.v()
            .out
            .println(
                "["
                    + body.getMethod().getName()
                    + "] Aggregating iteration "
                    + aggregateCount
                    + "...");

      // body.printTo(new java.io.PrintWriter(G.v().out, true));

      changed = internalAggregate(body, boxToZone, onlyStackVars);

      aggregateCount++;
    } while (changed);

    if (Options.v().time()) Timers.v().aggregationTimer.end();
  }
  /**
   * Make sure that all invoke special targets are cloned into the class from ancestors. This might
   * mean that we have to clone hidden methods, and change their names. So clone them in, and update
   * the clone to original map, and update the invoke special Also, this will update invoke specials
   * that target methods cloned in previous call to above cloneReachableNonHiddenAncestorMethods()
   */
  private void cloneHiddenAncestorMethodsAndFixInvokeSpecial() {
    Set<SootClass> parents = SootUtils.getParents(clazz);

    boolean debug = false; // (clazz.getName().contains("ResultDisplayer"));

    boolean cloneAdded = false;
    do {
      cloneAdded = false;
      for (SootMethod method : clazz.getMethods()) {

        if (method.isAbstract() || method.isPhantom() || !method.isConcrete()) continue;

        if (debug) System.out.println(method);

        Body body = null;
        try {
          body = method.retrieveActiveBody();
        } catch (Exception ex) {
          logger.info("Exception retrieving method body {}", ex);
          continue;
        }

        StmtBody stmtBody = (StmtBody) body;

        Chain units = stmtBody.getUnits();
        Iterator stmtIt = units.iterator();

        while (stmtIt.hasNext()) {
          Stmt stmt = (Stmt) stmtIt.next();

          if (stmt.containsInvokeExpr() && stmt.getInvokeExpr() instanceof SpecialInvokeExpr) {
            SpecialInvokeExpr si = (SpecialInvokeExpr) stmt.getInvokeExpr();

            SootMethod target = resolveSpecialInvokeTarget(si); // si.getMethod();

            if (debug) System.out.printf("\t%s %s", si, target);

            if (clonedToOriginal.values().contains(target)) {
              // found target of invoke special, and it has been cloned, so change the invoke
              // special
              SootMethod cloneOfTarget = clonedToOriginal.inverse().get(target);
              si.setMethodRef(cloneOfTarget.makeRef());
              if (debug) System.out.println("\tChange ref " + cloneOfTarget);
            } else if (parents.contains(target.getDeclaringClass())) {
              // target has not been cloned, but should be cloned, so clone it and change ref of
              // invoke
              String name = target.getName() + CLONED_METHOD_SUFFIX + (cloned_method_id++);
              SootMethod clonedMethod = cloneMethod(target, name);
              si.setMethodRef(clonedMethod.makeRef());
              cloneAdded = true;
              if (debug) System.out.println("\tClone and Change ref " + clonedMethod);
            }
          }
        }
      }
    } while (cloneAdded);
  }
  private static boolean internalAggregate(
      StmtBody body, Map<ValueBox, Zone> boxToZone, boolean onlyStackVars) {
    LocalUses localUses;
    LocalDefs localDefs;
    ExceptionalUnitGraph graph;
    boolean hadAggregation = false;
    Chain<Unit> units = body.getUnits();

    graph = new ExceptionalUnitGraph(body);
    localDefs = new SmartLocalDefs(graph, new SimpleLiveLocals(graph));
    localUses = new SimpleLocalUses(graph, localDefs);

    List<Unit> unitList = new PseudoTopologicalOrderer<Unit>().newList(graph, false);
    for (Unit u : unitList) {
      if (!(u instanceof AssignStmt)) continue;
      AssignStmt s = (AssignStmt) u;

      Value lhs = s.getLeftOp();
      if (!(lhs instanceof Local)) continue;
      Local lhsLocal = (Local) lhs;

      if (onlyStackVars && !lhsLocal.getName().startsWith("$")) continue;

      List<UnitValueBoxPair> lu = localUses.getUsesOf(s);
      if (lu.size() != 1) continue;

      UnitValueBoxPair usepair = lu.get(0);
      Unit use = usepair.unit;
      ValueBox useBox = usepair.valueBox;

      List<Unit> ld = localDefs.getDefsOfAt(lhsLocal, use);
      if (ld.size() != 1) continue;

      // Check to make sure aggregation pair in the same zone
      if (boxToZone.get(s.getRightOpBox()) != boxToZone.get(usepair.valueBox)) {
        continue;
      }

      /* we need to check the path between def and use */
      /* to see if there are any intervening re-defs of RHS */
      /* in fact, we should check that this path is unique. */
      /* if the RHS uses only locals, then we know what
      to do; if RHS has a method invocation f(a, b,
      c) or field access, we must ban field writes, other method
      calls and (as usual) writes to a, b, c. */

      boolean cantAggr = false;
      boolean propagatingInvokeExpr = false;
      boolean propagatingFieldRef = false;
      boolean propagatingArrayRef = false;
      ArrayList<FieldRef> fieldRefList = new ArrayList<FieldRef>();

      LinkedList<Value> localsUsed = new LinkedList<Value>();
      for (ValueBox vb : s.getUseBoxes()) {
        Value v = vb.getValue();
        if (v instanceof Local) localsUsed.add(v);
        else if (v instanceof InvokeExpr) propagatingInvokeExpr = true;
        else if (v instanceof ArrayRef) propagatingArrayRef = true;
        else if (v instanceof FieldRef) {
          propagatingFieldRef = true;
          fieldRefList.add((FieldRef) v);
        }
      }

      // look for a path from s to use in graph.
      // only look in an extended basic block, though.

      List<Unit> path = graph.getExtendedBasicBlockPathBetween(s, use);

      if (path == null) continue;

      Iterator<Unit> pathIt = path.iterator();

      // skip s.
      if (pathIt.hasNext()) pathIt.next();

      while (pathIt.hasNext() && !cantAggr) {
        Stmt between = (Stmt) (pathIt.next());

        if (between != use) {
          // Check for killing definitions

          for (ValueBox vb : between.getDefBoxes()) {
            Value v = vb.getValue();
            if (localsUsed.contains(v)) {
              cantAggr = true;
              break;
            }

            if (propagatingInvokeExpr || propagatingFieldRef || propagatingArrayRef) {
              if (v instanceof FieldRef) {
                if (propagatingInvokeExpr) {
                  cantAggr = true;
                  break;
                } else if (propagatingFieldRef) {
                  // Can't aggregate a field access if passing a definition of a field
                  // with the same name, because they might be aliased
                  for (FieldRef fieldRef : fieldRefList) {
                    if (((FieldRef) v).getField() == fieldRef.getField()) {
                      cantAggr = true;
                      break;
                    }
                  }
                }
              } else if (v instanceof ArrayRef) {
                if (propagatingInvokeExpr) {
                  // Cannot aggregate an invoke expr past an array write
                  cantAggr = true;
                  break;
                } else if (propagatingArrayRef) {
                  // cannot aggregate an array read past a write
                  // this is somewhat conservative
                  // (if types differ they may not be aliased)

                  cantAggr = true;
                  break;
                }
              }
            }
          }

          // Make sure not propagating past a {enter,exit}Monitor
          if (propagatingInvokeExpr && between instanceof MonitorStmt) cantAggr = true;
        }

        // Check for intervening side effects due to method calls
        if (propagatingInvokeExpr || propagatingFieldRef || propagatingArrayRef) {
          for (final ValueBox box : between.getUseBoxes()) {
            if (between == use && box == useBox) {
              // Reached use point, stop looking for
              // side effects
              break;
            }

            Value v = box.getValue();

            if (v instanceof InvokeExpr
                || (propagatingInvokeExpr && (v instanceof FieldRef || v instanceof ArrayRef))) {
              cantAggr = true;
              break;
            }
          }
        }
      }

      // we give up: can't aggregate.
      if (cantAggr) {
        continue;
      }
      /* assuming that the d-u chains are correct, */
      /* we need not check the actual contents of ld */

      Value aggregatee = s.getRightOp();

      if (usepair.valueBox.canContainValue(aggregatee)) {
        boolean wasSimpleCopy = isSimpleCopy(usepair.unit);
        usepair.valueBox.setValue(aggregatee);
        units.remove(s);
        hadAggregation = true;
        // clean up the tags. If s was not a simple copy, the new statement should get
        // the tags of s.
        // OK, this fix was wrong. The condition should not be
        // "If s was not a simple copy", but rather "If usepair.unit
        // was a simple copy". This way, when there's a load of a constant
        // followed by an invoke, the invoke gets the tags.
        if (wasSimpleCopy) {
          // usepair.unit.removeAllTags();
          usepair.unit.addAllTagsOf(s);
        }
      } else {
        /*
        if(Options.v().verbose())
        {
            G.v().out.println("[debug] failed aggregation");
              G.v().out.println("[debug] tried to put "+aggregatee+
                             " into "+usepair.stmt +
                             ": in particular, "+usepair.valueBox);
              G.v().out.println("[debug] aggregatee instanceof Expr: "
                             +(aggregatee instanceof Expr));
        }*/
      }
    }
    return hadAggregation;
  }