New implementation of data structure analysis. Only local analysis has been

implemented so far.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2871 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 531 insertions, 130 deletions

diff --git a/lib/Analysis/DataStructure/DataStructure.cpp b/lib/Analysis/DataStructure/DataStructure.cpp
index 7575a5da5b..84e2cfbc47 100644
--- a/lib/Analysis/DataStructure/DataStructure.cpp
+++ b/lib/Analysis/DataStructure/DataStructure.cpp
@@ -1,165 +1,127 @@
-//===- DataStructure.cpp - Analysis for data structure identification -------=//
+//===- DataStructure.cpp - Implement the core data structure analysis -----===//
 //
-// Implement the LLVM data structure analysis library.
+// This file implements the core data structure functionality.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Analysis/DataStructure.h"
 #include "llvm/Module.h"
-#include <fstream>
+#include "llvm/DerivedTypes.h"
 #include <algorithm>
+#include "Support/STLExtras.h"
 
-//===----------------------------------------------------------------------===//
-// DataStructure Class Implementation
-//
+AnalysisID LocalDataStructures::ID(AnalysisID::create<LocalDataStructures>());
 
-AnalysisID DataStructure::ID(AnalysisID::create<DataStructure>());
+//===----------------------------------------------------------------------===//
+// DSNode Implementation
+//===----------------------------------------------------------------------===//
 
-// releaseMemory - If the pass pipeline is done with this pass, we can release
-// our memory... here...
-void DataStructure::releaseMemory() {
-  for (InfoMap::iterator I = DSInfo.begin(), E = DSInfo.end(); I != E; ++I) {
-    delete I->second.first;
-    delete I->second.second;
+DSNode::DSNode(enum NodeTy NT, const Type *T) : Ty(T), NodeType(NT) {
+  // If this node has any fields, allocate them now, but leave them null.
+  switch (T->getPrimitiveID()) {
+  case Type::PointerTyID: Links.resize(1); break;
+  case Type::ArrayTyID:   Links.resize(1); break;
+  case Type::StructTyID:
+    Links.resize(cast<StructType>(T)->getNumContainedTypes());
+    break;
+  default: break;
   }
+}
 
-  // Empty map so next time memory is released, data structures are not
-  // re-deleted.
-  DSInfo.clear();
+void DSNode::removeReferrer(DSNodeHandle *H) {
+  // Search backwards, because we depopulate the list from the back for
+  // efficiency (because it's a vector).
+  std::vector<DSNodeHandle*>::reverse_iterator I =
+    std::find(Referrers.rbegin(), Referrers.rend(), H);
+  assert(I != Referrers.rend() && "Referrer not pointing to node!");
+  Referrers.erase(I.base()-1);
 }
 
-// FIXME REMOVE
-#include <sys/time.h>
-#include "Support/CommandLine.h"
-
-cl::Flag   Time("t", "Print analysis time...");
-
-
-// print - Print out the analysis results...
-void DataStructure::print(std::ostream &O, Module *M) const {
-  if (Time) {
-    timeval TV1, TV2;
-    gettimeofday(&TV1, 0);
-    for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
-      if (!I->isExternal() && I->getName() == "main") {
-        //getDSGraph(*I);
-        getClosedDSGraph(I);
-      }
-    gettimeofday(&TV2, 0);
-    std::cerr << "Analysis took "
-         << (TV2.tv_sec-TV1.tv_sec)*1000000+(TV2.tv_usec-TV1.tv_usec)
-         << " microseconds.\n";
+// addEdgeTo - Add an edge from the current node to the specified node.  This
+// can cause merging of nodes in the graph.
+//
+void DSNode::addEdgeTo(unsigned LinkNo, DSNode *N) {
+  assert(LinkNo < Links.size() && "LinkNo out of range!");
+  if (N == 0 || Links[LinkNo] == N) return;  // Nothing to do
+  if (Links[LinkNo] == 0) {                  // No merging to perform
+    Links[LinkNo] = N;
+    return;
   }
 
-  for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
-    if (!I->isExternal()) {
-
-      std::string Filename = "ds." + I->getName() + ".dot";
-      O << "Writing '" << Filename << "'...";
-      std::ofstream F(Filename.c_str());
-
-      if (F.good()) {
-        F << "digraph DataStructures {\n"
-          << "\tnode [shape=Mrecord];\n"
-          << "\tedge [arrowtail=\"dot\"];\n"
-          << "\tsize=\"10,7.5\";\n"
-          << "\trotate=\"90\";\n";
-
-        getDSGraph(I).printFunction(F, "Local");
-        getClosedDSGraph(I).printFunction(F, "Closed");
-
-        F << "}\n";
-      } else {
-        O << "  error opening file for writing!\n";
-      }
-
-      if (Time) 
-        O << " [" << getDSGraph(I).getGraphSize() << ", "
-          << getClosedDSGraph(I).getGraphSize() << "]\n";
-      else
-        O << "\n";
-    }
+  // Merge the two nodes...
+  Links[LinkNo]->mergeWith(N);
 }
 
 
-//===----------------------------------------------------------------------===//
-// PointerVal Class Implementation
+// mergeWith - Merge this node into the specified node, moving all links to and
+// from the argument node into the current node.  The specified node may be a
+// null pointer (in which case, nothing happens).
 //
-
-void PointerVal::print(std::ostream &O) const {
-  if (Node) {
-    O << "  Node: " << Node->getCaption() << "[" << Index << "]\n";
-  } else {
-    O << "  NULL NODE\n";
+void DSNode::mergeWith(DSNode *N) {
+  if (N == 0 || N == this) return;  // Noop
+  assert(N->Ty == Ty && N->Links.size() == Links.size() &&
+         "Cannot merge nodes of two different types!");
+
+  // Remove all edges pointing at N, causing them to point to 'this' instead.
+  while (!N->Referrers.empty())
+    *N->Referrers.back() = this;
+
+  // Make all of the outgoing links of N now be outgoing links of this.  This
+  // can cause recursive merging!
+  //
+  for (unsigned i = 0, e = Links.size(); i != e; ++i) {
+    addEdgeTo(i, N->Links[i]);
+    N->Links[i] = 0;  // Reduce unneccesary edges in graph. N is dead
   }
-}
-
-//===----------------------------------------------------------------------===//
-// PointerValSet Class Implementation
-//
 
-void PointerValSet::addRefs() {
-  for (unsigned i = 0, e = Vals.size(); i != e; ++i)
-    Vals[i].Node->addReferrer(this);
+  NodeType |= N->NodeType;
+  N->NodeType = 0;   // N is now a dead node.
 }
 
-void PointerValSet::dropRefs() {
-  for (unsigned i = 0, e = Vals.size(); i != e; ++i)
-    Vals[i].Node->removeReferrer(this);
-}
-
-const PointerValSet &PointerValSet::operator=(const PointerValSet &PVS) {
-  dropRefs();
-  Vals.clear();
-  Vals = PVS.Vals;
-  addRefs();
-  return *this;
-}
-
-// operator< - Allow insertion into a map...
-bool PointerValSet::operator<(const PointerValSet &PVS) const {
-  if (Vals.size() < PVS.Vals.size()) return true;
-  if (Vals.size() > PVS.Vals.size()) return false;
-  if (Vals.size() == 1) return Vals[0] < PVS.Vals[0];  // Most common case
+//===----------------------------------------------------------------------===//
+// DSGraph Implementation
+//===----------------------------------------------------------------------===//
 
-  std::vector<PointerVal> S1(Vals), S2(PVS.Vals);
-  sort(S1.begin(), S1.end());
-  sort(S2.begin(), S2.end());
-  return S1 < S2;
-}
+DSGraph::~DSGraph() {
+  FunctionCalls.clear();
+  ValueMap.clear();
+  RetNode = 0;
 
-bool PointerValSet::operator==(const PointerValSet &PVS) const {
-  if (Vals.size() != PVS.Vals.size()) return false;
-  if (Vals.size() == 1) return Vals[0] == PVS.Vals[0];  // Most common case...
+#ifndef NDEBUG
+  // Drop all intra-node references, so that assertions don't fail...
+  std::for_each(Nodes.begin(), Nodes.end(),
+                std::mem_fun(&DSNode::dropAllReferences));
+#endif
 
-  std::vector<PointerVal> S1(Vals), S2(PVS.Vals);
-  sort(S1.begin(), S1.end());
-  sort(S2.begin(), S2.end());
-  return S1 == S2;
+  // Delete all of the nodes themselves...
+  std::for_each(Nodes.begin(), Nodes.end(), deleter<DSNode>);
 }
 
+//===----------------------------------------------------------------------===//
+// LocalDataStructures Implementation
+//===----------------------------------------------------------------------===//
 
-bool PointerValSet::add(const PointerVal &PV, Value *Pointer) {
-  if (std::find(Vals.begin(), Vals.end(), PV) != Vals.end())
-    return false;
-  Vals.push_back(PV);
-  if (Pointer) PV.Node->addPointer(Pointer);
-  PV.Node->addReferrer(this);
-  return true;
-}
+// releaseMemory - If the pass pipeline is done with this pass, we can release
+// our memory... here...
+//
+void LocalDataStructures::releaseMemory() {
+  for (std::map<Function*, DSGraph*>::iterator I = DSInfo.begin(),
+         E = DSInfo.end(); I != E; ++I)
+    delete I->second;
 
-// removePointerTo - Remove a single pointer val that points to the specified
-// node...
-void PointerValSet::removePointerTo(DSNode *Node) {
-  std::vector<PointerVal>::iterator I = std::find(Vals.begin(), Vals.end(), Node);
-  assert(I != Vals.end() && "Couldn't remove nonexistent edge!");
-  Vals.erase(I);
-  Node->removeReferrer(this);
+  // Empty map so next time memory is released, data structures are not
+  // re-deleted.
+  DSInfo.clear();
 }
 
+bool LocalDataStructures::run(Module &M) {
+  // Calculate all of the graphs...
+  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
+    if (!I->isExternal()) {
+      std::map<Function*, DSGraph*>::iterator DI = DSInfo.find(I);
+      if (DI == DSInfo.end() || DI->second == 0)
+        DSInfo.insert(std::make_pair(&*I, new DSGraph(*I)));
+    }
 
-void PointerValSet::print(std::ostream &O) const {
-  for (unsigned i = 0, e = Vals.size(); i != e; ++i)
-    Vals[i].print(O);
+  return false;
 }
-
diff --git a/lib/Analysis/DataStructure/Local.cpp b/lib/Analysis/DataStructure/Local.cpp
new file mode 100644
index 0000000000..87767ce417
--- /dev/null
+++ b/lib/Analysis/DataStructure/Local.cpp
@@ -0,0 +1,283 @@
+//===- ComputeLocal.cpp - Compute a local data structure graph for a fn ---===//
+//
+// Compute the local version of the data structure graph for a function.  The
+// external interface to this file is the DSGraph constructor.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/DataStructure.h"
+#include "llvm/Function.h"
+#include "llvm/iMemory.h"
+#include "llvm/iTerminators.h"
+#include "llvm/iPHINode.h"
+#include "llvm/iOther.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Support/InstVisitor.h"
+using std::map;
+using std::vector;
+
+//===----------------------------------------------------------------------===//
+//  GraphBuilder Class
+//===----------------------------------------------------------------------===//
+//
+// This class is the builder class that constructs the local data structure
+// graph by performing a single pass over the function in question.
+//
+
+namespace {
+  class GraphBuilder : InstVisitor<GraphBuilder> {
+    DSGraph &G;
+    vector<DSNode*> &Nodes;
+    DSNodeHandle &RetNode;               // Node that gets returned...
+    map<Value*, DSNodeHandle> &ValueMap;
+    vector<vector<DSNodeHandle> > &FunctionCalls;
+
+  public:
+    GraphBuilder(DSGraph &g, vector<DSNode*> &nodes, DSNodeHandle &retNode,
+                 map<Value*, DSNodeHandle> &vm,
+                 vector<vector<DSNodeHandle> > &fc)
+      : G(g), Nodes(nodes), RetNode(retNode), ValueMap(vm), FunctionCalls(fc) {
+      visit(G.getFunction());  // Single pass over the function
+      removeDeadNodes();
+    }
+
+  private:
+    // Visitor functions, used to handle each instruction type we encounter...
+    friend class InstVisitor<GraphBuilder>;
+    void visitMallocInst(MallocInst &MI) { handleAlloc(MI, DSNode::NewNode); }
+    void visitAllocaInst(AllocaInst &AI) { handleAlloc(AI, DSNode::AllocaNode);}
+    void handleAlloc(AllocationInst &AI, DSNode::NodeTy NT);
+
+    void visitPHINode(PHINode &PN);
+
+    void visitGetElementPtrInst(GetElementPtrInst &GEP);
+    void visitReturnInst(ReturnInst &RI);
+    void visitLoadInst(LoadInst &LI);
+    void visitStoreInst(StoreInst &SI);
+    void visitCallInst(CallInst &CI);
+    void visitSetCondInst(SetCondInst &SCI) {}  // SetEQ & friends are ignored
+    void visitFreeInst(FreeInst &FI) {}         // Ignore free instructions
+    void visitInstruction(Instruction &I) {
+#ifndef NDEBUG
+      bool bad = isa<PointerType>(I.getType());
+      for (Instruction::op_iterator i = I.op_begin(), E = I.op_end(); i!=E; ++i)
+        bad |= isa<PointerType>(i->get()->getType());
+      if (bad) {
+        std::cerr << "\n\n\nUNKNOWN PTR INSTRUCTION type: " << I << "\n\n\n";
+        assert(0 && "Cannot proceed");
+      }
+#endif
+    }
+
+  private:
+    // Helper functions used to implement the visitation functions...
+
+    // createNode - Create a new DSNode, ensuring that it is properly added to
+    // the graph.
+    //
+    DSNode *createNode(DSNode::NodeTy NodeType, const Type *Ty);
+
+    // getValueNode - Return a DSNode that corresponds the the specified LLVM
+    // value.  This either returns the already existing node, or creates a new
+    // one and adds it to the graph, if none exists.
+    //
+    DSNode *getValueNode(Value &V);
+
+    // getLink - This method is used to either return the specified link in the
+    // specified node if one exists.  If a link does not already exist (it's
+    // null), then we create a new node, link it, then return it.
+    //
+    DSNode *getLink(DSNode *Node, unsigned Link);
+
+    // getSubscriptedNode - Perform the basic getelementptr functionality that
+    // must be factored out of gep, load and store while they are all MAI's.
+    //
+    DSNode *getSubscriptedNode(MemAccessInst &MAI, DSNode *Ptr);
+
+    // removeDeadNodes - After the graph has been constructed, this method
+    // removes all unreachable nodes that are created because they got merged
+    // with other nodes in the graph.
+    //
+    void removeDeadNodes();
+  };
+}
+
+//===----------------------------------------------------------------------===//
+// DSGraph constructor - Simply use the GraphBuilder to construct the local
+// graph.
+DSGraph::DSGraph(Function &F) : Func(F), RetNode(0) {
+  // Use the graph builder to construct the local version of the graph
+  GraphBuilder B(*this, Nodes, RetNode, ValueMap, FunctionCalls);
+}
+
+
+//===----------------------------------------------------------------------===//
+// Helper method implementations...
+//
+
+
+// createNode - Create a new DSNode, ensuring that it is properly added to the
+// graph.
+//
+DSNode *GraphBuilder::createNode(DSNode::NodeTy NodeType, const Type *Ty) {
+  DSNode *N = new DSNode(NodeType, Ty);
+  Nodes.push_back(N);
+  return N;
+}
+
+
+// getValueNode - Return a DSNode that corresponds the the specified LLVM value.
+// This either returns the already existing node, or creates a new one and adds
+// it to the graph, if none exists.
+//
+DSNode *GraphBuilder::getValueNode(Value &V) {
+  assert(isa<PointerType>(V.getType()) && "Should only use pointer scalars!");
+  DSNodeHandle &N = ValueMap[&V];
+  if (N) return N;             // Already have a node?  Just return it...
+  
+  // Otherwise we need to create a new scalar node...
+  N = createNode(DSNode::ScalarNode, V.getType());
+
+  if (isa<GlobalValue>(V)) {
+    // Traverse the global graph, adding nodes for them all, and marking them
+    // all globals.  Be careful to mark functions global as well as the
+    // potential graph of global variables.
+    //
+    DSNode *G = getLink(N, 0);
+    G->NodeType |= DSNode::GlobalNode;
+  }
+
+  return N;
+}
+
+// getLink - This method is used to either return the specified link in the
+// specified node if one exists.  If a link does not already exist (it's
+// null), then we create a new node, link it, then return it.
+//
+DSNode *GraphBuilder::getLink(DSNode *Node, unsigned Link) {
+  assert(Link < Node->getNumLinks() && "Link accessed out of range!");
+  if (Node->getLink(Link) == 0) {
+    DSNode::NodeTy NT;
+    const Type *Ty;
+
+    switch (Node->getType()->getPrimitiveID()) {
+    case Type::PointerTyID:
+      Ty = cast<PointerType>(Node->getType())->getElementType();
+      NT = DSNode::ShadowNode;
+      break;
+    case Type::ArrayTyID:
+      Ty = cast<ArrayType>(Node->getType())->getElementType();
+      NT = DSNode::SubElement;
+      break;
+    case Type::StructTyID:
+      Ty = cast<StructType>(Node->getType())->getContainedType(Link);
+      NT = DSNode::SubElement;
+      break;
+    default:
+      assert(0 && "Unexpected type to dereference!");
+      abort();
+    }
+
+    DSNode *New = createNode(NT, Ty);
+    Node->addEdgeTo(Link, New);
+  }
+
+  return Node->getLink(Link);
+}
+
+// getSubscriptedNode - Perform the basic getelementptr functionality that must
+// be factored out of gep, load and store while they are all MAI's.
+//
+DSNode *GraphBuilder::getSubscriptedNode(MemAccessInst &MAI, DSNode *Ptr) {
+  for (unsigned i = MAI.getFirstIndexOperandNumber(), e = MAI.getNumOperands();
+       i != e; ++i)
+    if (MAI.getOperand(i)->getType() == Type::UIntTy)
+      Ptr = getLink(Ptr, 0);
+    else if (MAI.getOperand(i)->getType() == Type::UByteTy)
+      Ptr = getLink(Ptr, cast<ConstantUInt>(MAI.getOperand(i))->getValue());  
+
+  if (MAI.getFirstIndexOperandNumber() == MAI.getNumOperands())
+    Ptr = getLink(Ptr, 0);  // All MAI's have an implicit 0 if nothing else.
+
+  return Ptr;
+}
+
+
+// removeDeadNodes - After the graph has been constructed, this method removes
+// all unreachable nodes that are created because they got merged with other
+// nodes in the graph.  These nodes will all be trivially unreachable, so we
+// don't have to perform any non-trivial analysis here.
+//
+void GraphBuilder::removeDeadNodes() {
+  for (unsigned i = 0; i != Nodes.size(); )
+    if (!Nodes[i]->getReferrers().empty())
+      ++i;                                    // This node is alive!
+    else {                                    // This node is dead!
+      delete Nodes[i];                        // Free memory...
+      Nodes.erase(Nodes.begin()+i);           // Remove from node list...
+    }
+}
+
+
+
+
+//===----------------------------------------------------------------------===//
+// Specific instruction type handler implementations...
+//
+
+// Alloca & Malloc instruction implementation - Simply create a new memory
+// object, pointing the scalar to it.
+//
+void GraphBuilder::handleAlloc(AllocationInst &AI, DSNode::NodeTy NodeType) {
+  DSNode *Scalar = getValueNode(AI);
+  DSNode *New = createNode(NodeType, AI.getAllocatedType());
+  Scalar->addEdgeTo(New);   // Make the scalar point to the new node...
+}
+
+// PHINode - Make the scalar for the PHI node point to all of the things the
+// incoming values point to... which effectively causes them to be merged.
+//
+void GraphBuilder::visitPHINode(PHINode &PN) {
+  if (!isa<PointerType>(PN.getType())) return; // Only pointer PHIs
+
+  DSNode *Scalar = getValueNode(PN);
+  for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
+    Scalar->mergeWith(getValueNode(*PN.getIncomingValue(i)));
+}
+
+void GraphBuilder::visitGetElementPtrInst(GetElementPtrInst &GEP) {
+  DSNode *Scalar = getValueNode(GEP);
+  DSNode *Ptr    = getSubscriptedNode(GEP, getValueNode(*GEP.getOperand(0)));
+  Scalar->addEdgeTo(Ptr);
+}
+
+void GraphBuilder::visitLoadInst(LoadInst &LI) {
+  if (!isa<PointerType>(LI.getType())) return; // Only pointer PHIs
+  DSNode *Ptr    = getSubscriptedNode(LI, getValueNode(*LI.getOperand(0)));
+  getValueNode(LI)->mergeWith(Ptr);
+}
+
+void GraphBuilder::visitStoreInst(StoreInst &SI) {
+  if (!isa<PointerType>(SI.getOperand(0)->getType())) return;
+  DSNode *Value   = getValueNode(*SI.getOperand(0));
+  DSNode *DestPtr = getValueNode(*SI.getOperand(1));
+  Value->mergeWith(getSubscriptedNode(SI, DestPtr));
+}
+
+void GraphBuilder::visitReturnInst(ReturnInst &RI) {
+  if (RI.getNumOperands() && isa<PointerType>(RI.getOperand(0)->getType())) {
+    DSNode *Value = getValueNode(*RI.getOperand(0));
+    Value->mergeWith(RetNode);
+    RetNode = Value;
+  }
+}
+
+void GraphBuilder::visitCallInst(CallInst &CI) {
+  FunctionCalls.push_back(vector<DSNodeHandle>());
+  vector<DSNodeHandle> &Args = FunctionCalls.back();
+
+  for (unsigned i = 0, e = CI.getNumOperands(); i != e; ++i)
+    if (isa<PointerType>(CI.getOperand(i)->getType()))
+      Args.push_back(getValueNode(*CI.getOperand(i)));
+}
diff --git a/lib/Analysis/DataStructure/Printer.cpp b/lib/Analysis/DataStructure/Printer.cpp
new file mode 100644
index 0000000000..c0caaa07d7
--- /dev/null
+++ b/lib/Analysis/DataStructure/Printer.cpp
@@ -0,0 +1,156 @@
+//===- Printer.cpp - Code for printing data structure graphs nicely -------===//
+//
+// This file implements the 'dot' graph printer.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/DataStructure.h"
+#include "llvm/Module.h"
+#include "llvm/Assembly/Writer.h"
+#include <fstream>
+#include <sstream>
+
+void DSNode::dump() const { print(std::cerr, 0); }
+
+std::string DSNode::getCaption(Function *F) const {
+  std::stringstream OS;
+  WriteTypeSymbolic(OS, getType(), F ? F->getParent() : 0);
+
+  OS << " ";
+  if (NodeType & ScalarNode) OS << "S";
+  if (NodeType & AllocaNode) OS << "A";
+  if (NodeType & NewNode   ) OS << "N";
+  if (NodeType & GlobalNode) OS << "G";
+  if (NodeType & SubElement) OS << "E";
+  if (NodeType & CastNode  ) OS << "C";
+
+  return OS.str();
+}
+
+static std::string getValueName(Value *V, Function &F) {
+  std::stringstream OS;
+  WriteAsOperand(OS, V, true, true, F.getParent());
+  return OS.str();
+}
+
+
+
+static void replaceIn(std::string &S, char From, const std::string &To) {
+  for (unsigned i = 0; i < S.size(); )
+    if (S[i] == From) {
+      S.replace(S.begin()+i, S.begin()+i+1,
+                To.begin(), To.end());
+      i += To.size();
+    } else {
+      ++i;
+    }
+}
+
+static string escapeLabel(const string &In) {
+  string Label(In);
+  replaceIn(Label, '\\', "\\\\");  // Escape caption...
+  replaceIn(Label, ' ', "\\ ");
+  replaceIn(Label, '{', "\\{");
+  replaceIn(Label, '}', "\\}");
+  return Label;
+}
+
+static void writeEdge(std::ostream &O, const void *SrcNode,
+                      const char *SrcNodePortName, int SrcNodeIdx,
+                      const DSNode *VS, const string &EdgeAttr = "") {
+  O << "\tNode" << SrcNode << SrcNodePortName;
+  if (SrcNodeIdx != -1) O << SrcNodeIdx;
+  O << " -> Node" << (void*)VS;
+
+  if (!EdgeAttr.empty())
+    O << "[" << EdgeAttr << "]";
+  O << ";\n";
+}
+
+void DSNode::print(std::ostream &O, Function *F) const {
+  string Caption = escapeLabel(getCaption(F));
+
+  O << "\tNode" << (void*)this << " [ label =\"{" << Caption;
+
+  if (!Links.empty()) {
+    O << "|{";
+    for (unsigned i = 0; i < Links.size(); ++i) {
+      if (i) O << "|";
+      O << "<g" << i << ">";
+    }
+    O << "}";
+  }
+  O << "}\"];\n";
+
+  for (unsigned i = 0; i < Links.size(); ++i)
+    if (Links[i])
+      writeEdge(O, this, ":g", i, Links[i]);
+}
+
+void DSGraph::print(std::ostream &O) const {
+  O << "digraph DataStructures {\n"
+    << "\tnode [shape=Mrecord];\n"
+    << "\tedge [arrowtail=\"dot\"];\n"
+    << "\tsize=\"10,7.5\";\n"
+    << "\trotate=\"90\";\n"
+    << "\tlabel=\"Function\\ " << Func.getName() << "\";\n\n";
+
+  // Output all of the nodes...
+  for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
+    Nodes[i]->print(O, &Func);
+
+  O << "\n";
+  // Output all of the nodes edges for scalar labels
+  for (std::map<Value*, DSNodeHandle>::const_iterator I = ValueMap.begin(),
+         E = ValueMap.end(); I != E; ++I) {
+    O << "\tNode" << (void*)I->first << "[ shape=circle, label =\""
+      << escapeLabel(getValueName(I->first, Func)) << "\",style=dotted];\n";
+    writeEdge(O, I->first, "",-1, I->second.get(),"arrowtail=tee,style=dotted");
+  }
+
+  // Output the returned value pointer...
+  if (RetNode != 0) {
+    O << "\tNode0x1" << "[ shape=circle, label =\""
+      << escapeLabel("Return") << "\"];\n";
+    writeEdge(O, (void*)1, "", -1, RetNode, "arrowtail=tee,style=dotted");
+  }    
+
+  // Output all of the call nodes...
+  for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) {
+    const std::vector<DSNodeHandle> &Call = FunctionCalls[i];
+    O << "\tNode" << (void*)&Call << " [shape=record,label=\"{call|{";
+    for (unsigned j = 0, e = Call.size(); j != e; ++j) {
+      if (j) O << "|";
+      O << "<g" << j << ">";
+    }
+    O << "}}\"];\n";
+
+    for (unsigned j = 0, e = Call.size(); j != e; ++j)
+      if (Call[j])
+        writeEdge(O, &Call, ":g", j, Call[j]);
+  }
+
+
+  O << "}\n";
+}
+
+
+
+
+// print - Print out the analysis results...
+void LocalDataStructures::print(std::ostream &O, Module *M) const {
+  for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
+    if (!I->isExternal()) {
+      std::string Filename = "ds." + I->getName() + ".dot";
+      O << "Writing '" << Filename << "'...";
+      std::ofstream F(Filename.c_str());
+
+      if (F.good()) {
+        DSGraph &Graph = getDSGraph(*I);
+        Graph.print(F);
+        O << " [" << Graph.getGraphSize() << "]\n";
+      } else {
+        O << "  error opening file for writing!\n";
+      }
+    }
+}