/**
   * 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();
  }
  SimpleLiveLocalsAnalysis(UnitGraph g) {
    super(g);

    if (Options.v().time()) Timers.v().liveSetupTimer.start();

    emptySet = new ArraySparseSet();

    // Create kill sets.
    {
      unitToKillSet = new HashMap<Unit, FlowSet>(g.size() * 2 + 1, 0.7f);

      Iterator unitIt = g.iterator();

      while (unitIt.hasNext()) {
        Unit s = (Unit) unitIt.next();

        FlowSet killSet = emptySet.clone();

        Iterator boxIt = s.getDefBoxes().iterator();

        while (boxIt.hasNext()) {
          ValueBox box = (ValueBox) boxIt.next();

          if (box.getValue() instanceof Local) killSet.add(box.getValue(), killSet);
        }

        unitToKillSet.put(s, killSet);
      }
    }

    // Create generate sets
    {
      unitToGenerateSet = new HashMap<Unit, FlowSet>(g.size() * 2 + 1, 0.7f);

      Iterator unitIt = g.iterator();

      while (unitIt.hasNext()) {
        Unit s = (Unit) unitIt.next();

        FlowSet genSet = emptySet.clone();

        Iterator boxIt = s.getUseBoxes().iterator();

        while (boxIt.hasNext()) {
          ValueBox box = (ValueBox) boxIt.next();

          if (box.getValue() instanceof Local) genSet.add(box.getValue(), genSet);
        }

        unitToGenerateSet.put(s, genSet);
      }
    }

    if (Options.v().time()) Timers.v().liveSetupTimer.end();

    if (Options.v().time()) Timers.v().liveAnalysisTimer.start();

    doAnalysis();

    if (Options.v().time()) Timers.v().liveAnalysisTimer.end();
  }