Пример #1
0
// The weight on each edge is the increment required along any path that
// contains that edge.
void BallLarusDag::calculatePathNumbersFrom(BallLarusNode* node) {
  if(node == getExit())
    // The Exit node must be base case
    node->setNumberPaths(1);
  else {
    unsigned sumPaths = 0;
    BallLarusNode* succNode;

    for(BLEdgeIterator succ = node->succBegin(), end = node->succEnd();
        succ != end; succ++) {
      if( (*succ)->getType() == BallLarusEdge::BACKEDGE ||
          (*succ)->getType() == BallLarusEdge::SPLITEDGE )
        continue;

      (*succ)->setWeight(sumPaths);
      succNode = (*succ)->getTarget();

      if( !succNode->getNumberPaths() )
        return;
      sumPaths += succNode->getNumberPaths();
    }

    node->setNumberPaths(sumPaths);
  }
}
Пример #2
0
// Calculate the path numbers by assigning edge increments as prescribed
// in Ball-Larus path profiling.
void BallLarusDag::calculatePathNumbers() {
  BallLarusNode* node;
  std::queue<BallLarusNode*> bfsQueue;
  bfsQueue.push(getExit());

  while(bfsQueue.size() > 0) {
    node = bfsQueue.front();

    DEBUG(dbgs() << "calculatePathNumbers on " << node->getName() << "\n");

    bfsQueue.pop();
    unsigned prevPathNumber = node->getNumberPaths();
    calculatePathNumbersFrom(node);

    // Check for DAG splitting
    if( node->getNumberPaths() > 100000000 && node != getRoot() ) {
      // Add new phony edge from the split-node to the DAG's exit
      BallLarusEdge* exitEdge = addEdge(node, getExit(), 0);
      exitEdge->setType(BallLarusEdge::SPLITEDGE_PHONY);

      // Counters to handle the possibility of a multi-graph
      BasicBlock* oldTarget = 0;
      unsigned duplicateNumber = 0;

      // Iterate through each successor edge, adding phony edges
      for( BLEdgeIterator succ = node->succBegin(), end = node->succEnd();
           succ != end; oldTarget = (*succ)->getTarget()->getBlock(), succ++ ) {

        if( (*succ)->getType() == BallLarusEdge::NORMAL ) {
          // is this edge a duplicate?
          if( oldTarget != (*succ)->getTarget()->getBlock() )
            duplicateNumber = 0;

          // create the new phony edge: root -> succ
          BallLarusEdge* rootEdge =
            addEdge(getRoot(), (*succ)->getTarget(), duplicateNumber++);
          rootEdge->setType(BallLarusEdge::SPLITEDGE_PHONY);
          rootEdge->setRealEdge(*succ);

          // split on this edge and reference it's exit/root phony edges
          (*succ)->setType(BallLarusEdge::SPLITEDGE);
          (*succ)->setPhonyRoot(rootEdge);
          (*succ)->setPhonyExit(exitEdge);
          (*succ)->setWeight(0);
        }
      }

      calculatePathNumbersFrom(node);
    }

    DEBUG(dbgs() << "prev, new number paths " << prevPathNumber << ", "
          << node->getNumberPaths() << ".\n");

    if(prevPathNumber == 0 && node->getNumberPaths() != 0) {
      DEBUG(dbgs() << "node ready : " << node->getName() << "\n");
      for(BLEdgeIterator pred = node->predBegin(), end = node->predEnd();
          pred != end; pred++) {
        if( (*pred)->getType() == BallLarusEdge::BACKEDGE ||
            (*pred)->getType() == BallLarusEdge::SPLITEDGE )
          continue;

        BallLarusNode* nextNode = (*pred)->getSource();
        // not yet visited?
        if(nextNode->getNumberPaths() == 0)
          bfsQueue.push(nextNode);
      }
    }
  }

  DEBUG(dbgs() << "\tNumber of paths: " << getRoot()->getNumberPaths() << "\n");
}