C++ DSGraph::computeGToGGMapping方法代码示例

//
// Method: findGlobalPoolNodes()
//
// Description:
//  This method finds DSNodes that are reachable from globals and that need a
//  pool.  The Automatic Pool Allocation transform will use the returned
//  information to build global pools for the DSNodes in question.
//
//  Note that this method does not assign DSNodes to pools; it merely decides
//  which DSNodes are reachable from globals and will need a pool of global
//  scope.
//
// Outputs:
//  Nodes - The DSNodes that are both reachable from globals and which should
//          have global pools will be *added* to this container.
//
void
AllHeapNodesHeuristic::findGlobalPoolNodes (DSNodeSet_t & Nodes) {
  // Get the globals graph for the program.
  DSGraph* GG = Graphs->getGlobalsGraph();

  // Get all of the nodes reachable from globals.
  DenseSet<const DSNode*> GlobalHeapNodes;
  GetNodesReachableFromGlobals (GG, GlobalHeapNodes);
  //
  // Create a global pool for each global DSNode.
  //
  for (DenseSet<const DSNode *>::iterator NI = GlobalHeapNodes.begin();
              NI != GlobalHeapNodes.end();++NI) {
    const DSNode * N = *NI;
    PoolMap[N] = OnePool(N);
  }

  //
  // Now find all DSNodes belonging to function-local DSGraphs which are
  // mirrored in the globals graph.  These DSNodes require a global pool, too.
  //
  for (Module::iterator F = M->begin(); F != M->end(); ++F) {
    if (Graphs->hasDSGraph(*F)) {
      DSGraph* G = Graphs->getDSGraph(*F);
      DSGraph::NodeMapTy NodeMap;
      G->computeGToGGMapping (NodeMap);
      //
      // Scan through all DSNodes in the local graph.  If a local DSNode has a
      // corresponding DSNode in the globals graph that is reachable from a 
      // global, then add the local DSNode to the set of DSNodes reachable from
      // a global.
      //
      DSGraph::node_iterator ni = G->node_begin();
      for (; ni != G->node_end(); ++ni) {
        DSNode * N = ni;
        DSNode * GGN = NodeMap[N].getNode();
        
        //assert (!GGN || GlobalHeapNodes.count (GGN));
        if (GGN && GlobalHeapNodes.count (GGN))
          PoolMap[GGN].NodesInPool.push_back (N);
      }
    }
  }

  //
  // Copy the values into the output container.  Note that DenseSet has no
  // iterator traits (or whatever allows us to treat DenseSet has a generic
  // container), so we have to use a loop to copy values from the DenseSet into
  // the output container.
  //
  for (DenseSet<const DSNode*>::iterator I = GlobalHeapNodes.begin(),
         E = GlobalHeapNodes.end(); I != E; ++I) {
    Nodes.insert (*I);
  }

  return;
}

//
// Method: getLocalPoolNodes()
//
// Description:
//  For a given function, determine which DSNodes for that function should have
//  local pools created for them.
//
void
Heuristic::getLocalPoolNodes (const Function & F, DSNodeList_t & Nodes) {
  //
  // Get the DSGraph of the specified function.  If the DSGraph has no nodes,
  // then there is nothing we need to do.
  //
  DSGraph* G = Graphs->getDSGraph(F);
  if (G->node_begin() == G->node_end()) return;

  //
  // Calculate which DSNodes are reachable from globals.  If a node is reachable
  // from a global, we will create a global pool for it, so no argument passage
  // is required.
  Graphs->getGlobalsGraph();

  // Map all node reachable from this global to the corresponding nodes in
  // the globals graph.
  DSGraph::NodeMapTy GlobalsGraphNodeMapping;
  G->computeGToGGMapping(GlobalsGraphNodeMapping);

  //
  // Loop over all of the nodes which are non-escaping, adding pool-allocatable
  // ones to the NodesToPA vector.  In other words, scan over the DSGraph and
  // find nodes for which a new pool must be created within this function.
  //
  for (DSGraph::node_iterator I = G->node_begin(), E = G->node_end();
       I != E;
       ++I){
    // Get the DSNode and, if applicable, its mirror in the globals graph
    DSNode * N   = I;
    DSNode * GGN = GlobalsGraphNodeMapping[N].getNode();

    //
    // Only the following nodes are pool allocated:
    //  1) Local Heap nodes
    //  2) Nodes which are mirrored in the globals graph and, in the globals
    //     graph, are heap nodes.
    //
    if ((N->isHeapNode()) || (GGN && GGN->isHeapNode())) {
      if (!(GlobalPoolNodes.count (N) || GlobalPoolNodes.count (GGN))) {
        // Otherwise, if it was not passed in from outside the function, it must
        // be a local pool!
        assert((!N->isGlobalNode() || N->isPtrToIntNode()) && "Should be in global mapping!");
        if(!N->isPtrToIntNode()) {
          Nodes.push_back (N);
        }
      }
    }
  }

  return;
}

// Get all nodes in all function DSGraphs and the global DSGraph that contain
// global values.
void CSDataRando::findGlobalNodes(Module &M) {
  DSGraph *GG = DSA->getGlobalsGraph();
  for (auto i = GG->node_begin(), e = GG->node_end(); i != e; i++) {
    GlobalNodes.insert(&*i);
  }

  for (Function &F : M) {
    if ((!F.isDeclaration()) && DSA->hasDSGraph(F)) {
      DSGraph *G = DSA->getDSGraph(F);
      FuncInfo &FI = FunctionInfo[&F];
      DSGraph::NodeMapTy NodeMap;
      G->computeGToGGMapping(NodeMap);
      for (auto i : NodeMap) {
        GlobalNodes.insert(i.first);
        FI.ToGlobalNodeMap[i.first] = i.second.getNode();
      }
    }
  }
}

//
// Method: findGlobalPoolNodes()
//
// Description:
//  This method finds DSNodes that are reachable from globals and that need a
//  pool.  The Automatic Pool Allocation transform will use the returned
//  information to build global pools for the DSNodes in question.
//
//  For efficiency, this method also determines which DSNodes should be in the
//  same pool.
//
// Outputs:
//  Nodes - The DSNodes that are both reachable from globals and which should
//          have global pools will be *added* to this container.
//
void
AllNodesHeuristic::findGlobalPoolNodes (DSNodeSet_t & Nodes) {
    // Get the globals graph for the program.
    DSGraph* GG = Graphs->getGlobalsGraph();

    //
    // Get all of the nodes reachable from globals.
    //
    DenseSet<const DSNode*> GlobalNodes;
    GetNodesReachableFromGlobals (GG, GlobalNodes);

    //
    // Create a global pool for each global DSNode.
    //
    for (DenseSet<const DSNode *>::iterator NI = GlobalNodes.begin();
            NI != GlobalNodes.end();
            ++NI) {
        const DSNode * N = *NI;
        PoolMap[N] = OnePool(N);
    }

    //
    // Now find all DSNodes belonging to function-local DSGraphs which are
    // mirrored in the globals graph.  These DSNodes require a global pool, too,
    // but must use the same pool as the one assigned to the corresponding global
    // DSNode.
    //
    for (Module::iterator F = M->begin(); F != M->end(); ++F) {
        //
        // Ignore functions that have no DSGraph.
        //
        if (!(Graphs->hasDSGraph(*F))) continue;

        //
        // Compute a mapping between local DSNodes and DSNodes in the globals
        // graph.
        //
        DSGraph* G = Graphs->getDSGraph(*F);
        DSGraph::NodeMapTy NodeMap;
        G->computeGToGGMapping (NodeMap);

        //
        // Scan through all DSNodes in the local graph.  If a local DSNode has a
        // corresponding DSNode in the globals graph that is reachable from a
        // global, then add the local DSNode to the set of DSNodes reachable from
        // a global.
        //
        DSGraph::node_iterator ni = G->node_begin();
        for (; ni != G->node_end(); ++ni) {
            DSNode * N = ni;
            DSNode * GGN = NodeMap[N].getNode();

            assert (!GGN || GlobalNodes.count (GGN));
            if (GGN && GlobalNodes.count (GGN))
                PoolMap[GGN].NodesInPool.push_back (N);
        }
    }

    //
    // Scan through all the local graphs looking for DSNodes which may be
    // reachable by a global.  These nodes may not end up in the globals graph
    // because of the fact that DSA doesn't actually know what is happening to
    // them.
    //
    // FIXME: I believe this code causes a condition in which a local DSNode is
    //        given a local pool in one function but not in other functions.
    //        Someone needs to investigate whether DSA is being consistent here,
    //        and if not, if that inconsistency is correct.
    //
#if 0
    for (Module::iterator F = M->begin(); F != M->end(); ++F) {
        if (F->isDeclaration()) continue;
        DSGraph* G = Graphs->getDSGraph(*F);
        for (DSGraph::node_iterator I = G->node_begin(), E = G->node_end();
                I != E;
                ++I) {
            DSNode * Node = I;
            if (Node->isExternalNode() || Node->isUnknownNode()) {
                GlobalNodes.insert (Node);
            }
        }
    }
#endif

    //
//.........这里部分代码省略.........

/// ProcessNodesReachableFromGlobals - If we inferred anything about nodes
/// reachable from globals, we have to make sure that we incorporate data for
/// all graphs that include those globals due to the nature of the globals
/// graph.
///
void StructureFieldVisitorBase::
ProcessNodesReachableFromGlobals(DSGraph &DSG,
                                 std::multimap<DSNode*,LatticeValue*> &NodeLVs){
  // Start by marking all nodes reachable from globals.
  DSScalarMap &SM = DSG.getScalarMap();
  if (SM.global_begin() == SM.global_end()) return;

  hash_set<const DSNode*> Reachable;
  for (DSScalarMap::global_iterator GI = SM.global_begin(),
         E = SM.global_end(); GI != E; ++GI)
    SM[*GI].getNode()->markReachableNodes(Reachable);
  if (Reachable.empty()) return;
  
  // If any of the nodes with dataflow facts are reachable from the globals
  // graph, we have to do the GG processing step.
  bool MustProcessThroughGlobalsGraph = false;
  for (std::multimap<DSNode*, LatticeValue*>::iterator I = NodeLVs.begin(),
         E = NodeLVs.end(); I != E; ++I)
    if (Reachable.count(I->first)) {
      MustProcessThroughGlobalsGraph = true;
      break;
    }
  
  if (!MustProcessThroughGlobalsGraph) return;
  Reachable.clear();

  // Compute the mapping from DSG to the globals graph.
  DSGraph::NodeMapTy DSGToGGMap;
  DSG.computeGToGGMapping(DSGToGGMap);

  // Most of the times when we find facts about things reachable from globals we
  // we are in the main graph.  This means that we have *all* of the globals
  // graph in this DSG.  To be efficient, we compute the minimum set of globals
  // that can reach any of the NodeLVs facts.
  //
  // I'm not aware of any wonderful way of computing the set of globals that
  // points to the set of nodes in NodeLVs that is not N^2 in either NodeLVs or
  // the number of globals, except to compute the inverse of DSG.  As such, we
  // compute the inverse graph of DSG, which basically has the edges going from
  // pointed to nodes to pointing nodes.  Because we only care about one
  // connectedness properties, we ignore field info.  In addition, we only
  // compute inverse of the portion of the graph reachable from the globals.
  std::set<std::pair<DSNode*,DSNode*> > InverseGraph;

  for (DSScalarMap::global_iterator GI = SM.global_begin(),
         E = SM.global_end(); GI != E; ++GI)
    ComputeInverseGraphFrom(SM[*GI].getNode(), InverseGraph);

  // Okay, now that we have our bastardized inverse graph, compute the set of
  // globals nodes reachable from our lattice nodes.
  for (std::multimap<DSNode*, LatticeValue*>::iterator I = NodeLVs.begin(),
         E = NodeLVs.end(); I != E; ++I)
    ComputeNodesReachableFrom(I->first, InverseGraph, Reachable);
 
  // Now that we know which nodes point to the data flow facts, figure out which
  // globals point to the data flow facts.
  std::set<GlobalValue*> Globals;
  for (hash_set<const DSNode*>::iterator I = Reachable.begin(),
         E = Reachable.end(); I != E; ++I)
    Globals.insert((*I)->globals_begin(), (*I)->globals_end());

  // Finally, loop over all of the DSGraphs for the program, computing
  // information for the graph if not done already, mapping the result into our
  // context.
  for (hash_map<const Function*, DSGraph*>::iterator GI = ECG.DSInfo.begin(),
         E = ECG.DSInfo.end(); GI != E; ++GI) {
    DSGraph &FG = *GI->second;
    // Graphs can contain multiple functions, only process the graph once.
    if (GI->first != FG.retnodes_begin()->first ||
        // Also, do not bother reprocessing DSG.
        &FG == &DSG)
      continue;

    bool GraphUsesGlobal = false;
    for (std::set<GlobalValue*>::iterator I = Globals.begin(),
           E = Globals.end(); I != E; ++I)
      if (FG.getScalarMap().count(*I)) {
        GraphUsesGlobal = true;
        break;
      }

    // If this graph does not contain the global at all, there is no reason to
    // even think about it.
    if (!GraphUsesGlobal) continue;

    // Otherwise, compute the full set of dataflow effects of the function.
    std::multimap<DSNode*, LatticeValue*> &FGF = getCalleeFacts(FG);
    //std::cerr << "Computed: " << FG.getFunctionNames() << "\n";

#if 0
    for (std::multimap<DSNode*, LatticeValue*>::iterator I = FGF.begin(),
           E = FGF.end(); I != E; ++I)
      I->second->dump();
#endif
    // Compute the mapping of nodes in the globals graph to the function's
//.........这里部分代码省略.........