C++ ExplodedGraph::addRoot方法代码示例

ExplodedGraph*
ExplodedGraph::TrimInternal(const ExplodedNode* const* BeginSources,
                            const ExplodedNode* const* EndSources,
                            InterExplodedGraphMap* M,
                   llvm::DenseMap<const void*, const void*> *InverseMap) const {

  typedef llvm::DenseSet<const ExplodedNode*> Pass1Ty;
  Pass1Ty Pass1;

  typedef llvm::DenseMap<const ExplodedNode*, ExplodedNode*> Pass2Ty;
  Pass2Ty& Pass2 = M->M;

  SmallVector<const ExplodedNode*, 10> WL1, WL2;

  // ===- Pass 1 (reverse DFS) -===
  for (const ExplodedNode* const* I = BeginSources; I != EndSources; ++I) {
    assert(*I);
    WL1.push_back(*I);
  }

  // Process the first worklist until it is empty.  Because it is a std::list
  // it acts like a FIFO queue.
  while (!WL1.empty()) {
    const ExplodedNode *N = WL1.back();
    WL1.pop_back();

    // Have we already visited this node?  If so, continue to the next one.
    if (Pass1.count(N))
      continue;

    // Otherwise, mark this node as visited.
    Pass1.insert(N);

    // If this is a root enqueue it to the second worklist.
    if (N->Preds.empty()) {
      WL2.push_back(N);
      continue;
    }

    // Visit our predecessors and enqueue them.
    for (ExplodedNode::pred_iterator I = N->Preds.begin(), E = N->Preds.end();
         I != E; ++I)
      WL1.push_back(*I);
  }

  // We didn't hit a root? Return with a null pointer for the new graph.
  if (WL2.empty())
    return 0;

  // Create an empty graph.
  ExplodedGraph* G = MakeEmptyGraph();

  // ===- Pass 2 (forward DFS to construct the new graph) -===
  while (!WL2.empty()) {
    const ExplodedNode *N = WL2.back();
    WL2.pop_back();

    // Skip this node if we have already processed it.
    if (Pass2.find(N) != Pass2.end())
      continue;

    // Create the corresponding node in the new graph and record the mapping
    // from the old node to the new node.
    ExplodedNode *NewN = G->getNode(N->getLocation(), N->State, N->isSink(), 0);
    Pass2[N] = NewN;

    // Also record the reverse mapping from the new node to the old node.
    if (InverseMap) (*InverseMap)[NewN] = N;

    // If this node is a root, designate it as such in the graph.
    if (N->Preds.empty())
      G->addRoot(NewN);

    // In the case that some of the intended predecessors of NewN have already
    // been created, we should hook them up as predecessors.

    // Walk through the predecessors of 'N' and hook up their corresponding
    // nodes in the new graph (if any) to the freshly created node.
    for (ExplodedNode::pred_iterator I = N->Preds.begin(), E = N->Preds.end();
         I != E; ++I) {
      Pass2Ty::iterator PI = Pass2.find(*I);
      if (PI == Pass2.end())
        continue;

      NewN->addPredecessor(PI->second, *G);
    }

    // In the case that some of the intended successors of NewN have already
    // been created, we should hook them up as successors.  Otherwise, enqueue
    // the new nodes from the original graph that should have nodes created
    // in the new graph.
    for (ExplodedNode::succ_iterator I = N->Succs.begin(), E = N->Succs.end();
         I != E; ++I) {
      Pass2Ty::iterator PI = Pass2.find(*I);
      if (PI != Pass2.end()) {
        PI->second->addPredecessor(NewN, *G);
        continue;
      }

      // Enqueue nodes to the worklist that were marked during pass 1.
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