コード例 #1
0
ファイル: BlockSplitter.java プロジェクト: wrmsr/scale
  /**
   * Reverse if-convert a block. Return a new hyperblock starting with the reverse if-converted
   * block or null.
   */
  private Hyperblock reverseIfConvertBlock(PredicateBlock block) {
    int rp = block.getPredicate();
    boolean sense = block.isPredicatedOnTrue();

    // Insert a label at the beginning of the block.

    TripsLabel lab = (TripsLabel) gen.createLabel();
    gen.updateLabelIndex(lab);
    block.insertInstructionAtHead(lab);

    // Insert a branch to this block in its predecessors.

    for (int i = block.numInEdges() - 1; i > -1; i--) {
      PredicateBlock pred = (PredicateBlock) block.getInEdge(i);
      int rpPred = pred.getPredicate();
      boolean sensePred = pred.isPredicatedOnTrue();
      boolean needThunk = true;

      // Check if we need a thunk.

      if (!block.isPredicated()) {
        needThunk = false;
      } else if (pred.numOutEdges() == 1) {
        needThunk = false;
      } else if ((rp == rpPred) && (sense == sensePred)) {
        needThunk = false;
      }

      // Create a branch to the label and insert it.

      if (needThunk) {
        TripsBranch br = new TripsBranch(Opcodes.BRO, lab, 1, rp, sense);
        PredicateBlock thunk = new PredicateBlock(rp, sense);

        br.addTarget(lab, 0);
        thunk.appendInstruction(br);
        pred.addOutEdge(thunk);
        thunk.addInEdge(pred);
      } else {
        TripsBranch br = new TripsBranch(Opcodes.BRO, lab, 1, rpPred, sensePred);

        br.addTarget(lab, 0);
        pred.appendInstruction(br);
      }

      pred.deleteOutEdge(block);
      block.deleteInEdge(pred);
    }

    blocksReverseIfConvertedCount++;

    // Create the new hyperblock.

    BitVect predicates = removePredicates(block);
    Hyperblock hnew = new Hyperblock(block, predicates, regs);

    hnew.updateLastBlock();

    return hnew;
  }
コード例 #2
0
ファイル: BlockSplitter.java プロジェクト: wrmsr/scale
  /** Remove all the predicates which are not defined in the hyperblock. */
  private BitVect removePredicates(PredicateBlock start) {
    BitVect predicates = new BitVect();
    Stack<Node> wl = new Stack<Node>();

    // Determine all the predicates defined outside this hyperblock.

    start.nextVisit();
    start.setVisited();
    wl.add(start);

    while (!wl.isEmpty()) {
      PredicateBlock block = (PredicateBlock) wl.pop();
      block.pushOutEdges(wl);

      for (Instruction inst = block.getFirstInstruction(); inst != null; inst = inst.getNext()) {
        if (inst.isMarker()) {
          continue;
        }

        if (inst.isBranch()) {
          continue;
        }

        if (((TripsInstruction) inst).definesPredicate()) {
          predicates.set(inst.getDestRegister());
        }
      }
    }

    // Remove the predicates.

    start.nextVisit();
    start.setVisited();
    wl.add(start);

    while (!wl.isEmpty()) {
      PredicateBlock block = (PredicateBlock) wl.pop();
      block.pushOutEdges(wl);

      if (!block.isPredicated()) {
        continue;
      }

      int rp = block.getPredicate();
      if (predicates.get(rp)) {
        continue;
      }

      block.removePredicates();

      for (Instruction inst = block.getFirstInstruction(); inst != null; inst = inst.getNext()) {
        inst.removePredicates();
      }
    }

    return predicates;
  }