* Changes to make NodeType be private to DSNode.

* Add new MultiObject flag to DSNode which keeps track of whether or not
  multiple objects have been merged into the node, allowing must-alias info
  to be tracked.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@6794 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 107 insertions, 76 deletions

diff --git a/lib/Analysis/DataStructure/BottomUpClosure.cpp b/lib/Analysis/DataStructure/BottomUpClosure.cpp
index 0833a02..9f50436 100644
--- a/lib/Analysis/DataStructure/BottomUpClosure.cpp
+++ b/lib/Analysis/DataStructure/BottomUpClosure.cpp
@@ -33,7 +33,7 @@ static bool isVAHackFn(const Function *F) {
 // if the call sites are not external.
 //
 static inline bool isCompleteNode(DSNode *N) {
-  if (N->NodeType & DSNode::Incomplete) return false;
+  if (N->isIncomplete()) return false;
   const std::vector<GlobalValue*> &Callees = N->getGlobals();
   for (unsigned i = 0, e = Callees.size(); i != e; ++i)
     if (Callees[i]->isExternal())
diff --git a/lib/Analysis/DataStructure/DataStructure.cpp b/lib/Analysis/DataStructure/DataStructure.cpp
index 5f232e2..9e00860 100644
--- a/lib/Analysis/DataStructure/DataStructure.cpp
+++ b/lib/Analysis/DataStructure/DataStructure.cpp
@@ -49,8 +49,8 @@ DSNode *DSNodeHandle::HandleForwarding() const {
 // DSNode Implementation
 //===----------------------------------------------------------------------===//
 
-DSNode::DSNode(unsigned NT, const Type *T, DSGraph *G)
-  : NumReferrers(0), Size(0), ParentGraph(G), Ty(Type::VoidTy), NodeType(NT) {
+DSNode::DSNode(const Type *T, DSGraph *G)
+  : NumReferrers(0), Size(0), ParentGraph(G), Ty(Type::VoidTy), NodeType(0) {
   // Add the type entry if it is specified...
   if (T) mergeTypeInfo(T, 0);
   G->getNodes().push_back(this);
@@ -68,6 +68,12 @@ void DSNode::assertOK() const {
           Ty == Type::VoidTy && (Size == 0 ||
                                  (NodeType & DSNode::Array))) &&
          "Node not OK!");
+
+  // Check to ensure that the multiobject constraints are met...
+  unsigned Comp = NodeType & DSNode::Composition;
+  assert((NodeType & DSNode::MultiObject) || 
+         Comp == 0 || Comp == DSNode::AllocaNode || Comp == DSNode::HeapNode ||
+         Comp == DSNode::GlobalNode || Comp == DSNode::UnknownNode);
 }
 
 /// forwardNode - Mark this node as being obsolete, and all references to it
@@ -97,6 +103,8 @@ void DSNode::addGlobal(GlobalValue *GV) {
   if (I == Globals.end() || *I != GV) {
     //assert(GV->getType()->getElementType() == Ty);
     Globals.insert(I, GV);
+    if (NodeType & DSNode::Composition)
+      NodeType |= DSNode::MultiObject;
     NodeType |= GlobalNode;
   }
 }
@@ -112,7 +120,8 @@ void DSNode::foldNodeCompletely() {
   ++NumFolds;
 
   // Create the node we are going to forward to...
-  DSNode *DestNode = new DSNode(NodeType|DSNode::Array, 0, ParentGraph);
+  DSNode *DestNode = new DSNode(0, ParentGraph);
+  DestNode->NodeType = NodeType|DSNode::Array;
   DestNode->Ty = Type::VoidTy;
   DestNode->Size = 1;
   DestNode->Globals.swap(Globals);
@@ -446,7 +455,7 @@ void DSNode::MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH) {
   // Merge the type entries of the two nodes together...
   if (NH.getNode()->Ty != Type::VoidTy)
     CurNodeH.getNode()->mergeTypeInfo(NH.getNode()->Ty, NOffset);
-  assert((CurNodeH.getNode()->NodeType & DSNode::DEAD) == 0);
+  assert(!CurNodeH.getNode()->isDeadNode());
 
   // If we are merging a node with a completely folded node, then both nodes are
   // now completely folded.
@@ -471,12 +480,17 @@ void DSNode::MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH) {
 
   DSNode *N = NH.getNode();
   if (CurNodeH.getNode() == N || N == 0) return;
-  assert((CurNodeH.getNode()->NodeType & DSNode::DEAD) == 0);
+  assert(!CurNodeH.getNode()->isDeadNode());
 
-  // Start forwarding to the new node!
+  // Merge the NodeType information...
+  if ((CurNodeH.getNode()->NodeType & DSNode::Composition) != 0 && 
+      (N->NodeType & DSNode::Composition) != 0)
+    N->NodeType |= DSNode::MultiObject;   // Multiple composition -> multiobject
   CurNodeH.getNode()->NodeType |= N->NodeType;
+
+  // Start forwarding to the new node!
   N->forwardNode(CurNodeH.getNode(), NOffset);
-  assert((CurNodeH.getNode()->NodeType & DSNode::DEAD) == 0);
+  assert(!CurNodeH.getNode()->isDeadNode());
 
   // Make all of the outgoing links of N now be outgoing links of CurNodeH.
   //
@@ -522,8 +536,7 @@ void DSNode::mergeWith(const DSNodeHandle &NH, unsigned Offset) {
   if (N == 0 || (N == this && NH.getOffset() == Offset))
     return;  // Noop
 
-  assert((N->NodeType & DSNode::DEAD) == 0);
-  assert((NodeType & DSNode::DEAD) == 0);
+  assert(!N->isDeadNode() && !isDeadNode());
   assert(!hasNoReferrers() && "Should not try to fold a useless node!");
 
   if (N == this) {
@@ -630,13 +643,13 @@ DSNodeHandle DSGraph::cloneInto(const DSGraph &G,
   Nodes.reserve(FN+G.Nodes.size());
 
   // Remove alloca or mod/ref bits as specified...
-  unsigned clearBits = (CloneFlags & StripAllocaBit ? DSNode::AllocaNode : 0)
-    | (CloneFlags & StripModRefBits ? (DSNode::Modified | DSNode::Read) : 0);
-  clearBits |= DSNode::DEAD;  // Clear dead flag...
+  unsigned BitsToClear =((CloneFlags & StripAllocaBit) ? DSNode::AllocaNode : 0)
+    | ((CloneFlags & StripModRefBits) ? (DSNode::Modified | DSNode::Read) : 0);
+  BitsToClear |= DSNode::DEAD;  // Clear dead flag...
   for (unsigned i = 0, e = G.Nodes.size(); i != e; ++i) {
     DSNode *Old = G.Nodes[i];
     DSNode *New = new DSNode(*Old, this);
-    New->NodeType &= ~clearBits;
+    New->maskNodeTypes(~BitsToClear);
     OldNodeMap[Old] = New;
   }
 
@@ -743,16 +756,16 @@ void DSGraph::mergeInGraph(DSCallSite &CS, const DSGraph &Graph,
 
 // markIncompleteNodes - Mark the specified node as having contents that are not
 // known with the current analysis we have performed.  Because a node makes all
-// of the nodes it can reach imcomplete if the node itself is incomplete, we
+// of the nodes it can reach incomplete if the node itself is incomplete, we
 // must recursively traverse the data structure graph, marking all reachable
 // nodes as incomplete.
 //
 static void markIncompleteNode(DSNode *N) {
   // Stop recursion if no node, or if node already marked...
-  if (N == 0 || (N->NodeType & DSNode::Incomplete)) return;
+  if (N == 0 || (N->isIncomplete())) return;
 
   // Actually mark the node
-  N->NodeType |= DSNode::Incomplete;
+  N->setIncompleteMarker();
 
   // Recusively process children...
   for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
@@ -798,14 +811,15 @@ void DSGraph::markIncompleteNodes(unsigned Flags) {
   // Mark all global nodes as incomplete...
   if ((Flags & DSGraph::IgnoreGlobals) == 0)
     for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
-      if (Nodes[i]->NodeType & DSNode::GlobalNode && Nodes[i]->getNumLinks())
+      if (Nodes[i]->isGlobalNode() && Nodes[i]->getNumLinks())
         markIncompleteNode(Nodes[i]);
 }
 
 static inline void killIfUselessEdge(DSNodeHandle &Edge) {
   if (DSNode *N = Edge.getNode())  // Is there an edge?
     if (N->getNumReferrers() == 1)  // Does it point to a lonely node?
-      if ((N->NodeType & ~DSNode::Incomplete) == 0 && // No interesting info?
+      // No interesting info?
+      if ((N->getNodeFlags() & ~DSNode::Incomplete) == 0 &&
           N->getType() == Type::VoidTy && !N->isNodeCompletelyFolded())
         Edge.setNode(0);  // Kill the edge!
 }
@@ -835,7 +849,7 @@ static void removeIdenticalCalls(std::vector<DSCallSite> &Calls,
     // If the Callee is a useless edge, this must be an unreachable call site,
     // eliminate it.
     if (CS.isIndirectCall() && CS.getCalleeNode()->getNumReferrers() == 1 &&
-        CS.getCalleeNode()->NodeType == 0) {  // No useful info?
+        CS.getCalleeNode()->getNodeFlags() == 0) {  // No useful info?
       std::cerr << "WARNING: Useless call site found??\n";
       CS.swap(Calls.back());
       Calls.pop_back();
@@ -914,8 +928,7 @@ void DSGraph::removeTriviallyDeadNodes() {
 
   for (unsigned i = 0; i != Nodes.size(); ++i) {
     DSNode *Node = Nodes[i];
-    if (!(Node->NodeType & ~(DSNode::Composition | DSNode::Array |
-                             DSNode::DEAD))) {
+    if (!Node->isIncomplete() && !Node->isModified() && !Node->isRead()) {
       // This is a useless node if it has no mod/ref info (checked above),
       // outgoing edges (which it cannot, as it is not modified in this
       // context), and it has no incoming edges.  If it is a global node it may
@@ -923,7 +936,7 @@ void DSGraph::removeTriviallyDeadNodes() {
       // scalar map, so we check those now.
       //
       if (Node->getNumReferrers() == Node->getGlobals().size()) {
-        std::vector<GlobalValue*> &Globals = Node->getGlobals();
+        const std::vector<GlobalValue*> &Globals = Node->getGlobals();
 
         // Loop through and make sure all of the globals are referring directly
         // to the node...
@@ -932,20 +945,16 @@ void DSGraph::removeTriviallyDeadNodes() {
           assert(N == Node && "ScalarMap doesn't match globals list!");
         }
 
-        // Make sure numreferrers still agrees, if so, the node is truely dead.
+        // Make sure NumReferrers still agrees, if so, the node is truly dead.
         if (Node->getNumReferrers() == Globals.size()) {
           for (unsigned j = 0, e = Globals.size(); j != e; ++j)
             ScalarMap.erase(Globals[j]);
-
-          Globals.clear();
-          assert(Node->hasNoReferrers() && "Shouldn't have refs now!");
-          
-          Node->NodeType = DSNode::DEAD;
+          Node->makeNodeDead();
         }
       }
     }
 
-    if ((Node->NodeType & ~DSNode::DEAD) == 0 && Node->hasNoReferrers()) {
+    if (Node->getNodeFlags() == 0 && Node->hasNoReferrers()) {
       // This node is dead!
       delete Node;                        // Free memory...
       Nodes[i--] = Nodes.back();
@@ -1055,7 +1064,7 @@ void DSGraph::removeDeadNodes(unsigned Flags) {
       // these, prune the scalar pointing to it.
       //
       DSNode *N = I->second.getNode();
-      if (N->NodeType == DSNode::UnknownNode && !isa<Argument>(I->first)) {
+      if (N->isUnknownNode() && !isa<Argument>(I->first)) {
         ScalarMap.erase(I++);
       } else {
         I->second.getNode()->markReachableNodes(Alive);
@@ -1128,7 +1137,7 @@ void DSGraph::removeDeadNodes(unsigned Flags) {
         GlobalsGraph->Nodes.push_back(N);        // Move node to globals graph
         N->setParentGraph(GlobalsGraph);
       } else {                                 // Otherwise, delete the node
-        assert(((N->NodeType & DSNode::GlobalNode) == 0 ||
+        assert((!N->isGlobalNode() ||
                 (Flags & DSGraph::RemoveUnreachableGlobals))
                && "Killing a global?");
         //std::cerr << "[" << i+1 << "/" << DeadNodes.size()
@@ -1189,7 +1198,7 @@ void DSGraph::AssertGraphOK() const {
     assert(I->second.getNode() && "Null node in scalarmap!");
     AssertNodeInGraph(I->second.getNode());
     if (GlobalValue *GV = dyn_cast<GlobalValue>(I->first)) {
-      assert((I->second.getNode()->NodeType & DSNode::GlobalNode) &&
+      assert(I->second.getNode()->isGlobalNode() &&
              "Global points to node, but node isn't global?");
       AssertNodeContainsGlobal(I->second.getNode(), GV);
     }
diff --git a/lib/Analysis/DataStructure/DataStructureAA.cpp b/lib/Analysis/DataStructure/DataStructureAA.cpp
index 5c3d946..d7c40c6 100644
--- a/lib/Analysis/DataStructure/DataStructureAA.cpp
+++ b/lib/Analysis/DataStructure/DataStructureAA.cpp
@@ -68,15 +68,12 @@ static const Function *getValueFunction(const Value *V) {
 // alias - This is the only method here that does anything interesting...
 AliasAnalysis::AliasResult DSAA::alias(const Value *V1, unsigned V1Size,
                                        const Value *V2, unsigned V2Size) {
-  // FIXME: This should handle the Size argument as well!
+  if (V1 == V2) return MustAlias;
+
   const Function *F1 = getValueFunction(V1);
   const Function *F2 = getValueFunction(V2);
   assert((!F1 || !F2 || F1 == F2) && "Alias query for 2 different functions?");
   
-
-  // FIXME: This can return must alias if querying a DSNode for a global value
-  // where the node has only the G composition bit set, and only one entry in
-  // the globals list...
   if (F2) F1 = F2;
   if (F1) {
     // Get the graph for a function...
@@ -88,17 +85,33 @@ AliasAnalysis::AliasResult DSAA::alias(const Value *V1, unsigned V1Size,
       hash_map<Value*, DSNodeHandle>::iterator J = GSM.find((Value*)V2);
       if (J != GSM.end()) {
         assert(J->second.getNode() && "Scalar map points to null node?");
-        if (I->second.getNode() != J->second.getNode()) {
-          // Return noalias if one of the nodes is complete...
-          if ((~I->second.getNode()->NodeType | ~J->second.getNode()->NodeType)
-              & DSNode::Incomplete)
-            return NoAlias;
-          // both are incomplete, they may alias...
-        } else {
-          // Both point to the same node, see if they point to different
-          // offsets...  FIXME: This needs to know the size of the alias query
-          if (I->second.getOffset() != J->second.getOffset())
-            return NoAlias;
+
+        DSNode  *N1 = I->second.getNode(),  *N2 = J->second.getNode();
+        unsigned O1 = I->second.getOffset(), O2 = J->second.getOffset();
+        
+        // We can only make a judgement of one of the nodes is complete...
+        if (!N1->isIncomplete() || !N2->isIncomplete()) {
+          if (N1 != N2)
+            return NoAlias;   // Completely different nodes.
+
+          // Both point to the same node and same offset, and there is only one
+          // physical memory object represented in the node, return must alias.
+          if (O1 == O2 && !N1->isMultiObject())
+            return MustAlias; // Exactly the same object & offset
+
+          // See if they point to different offsets...  if so, we may be able to
+          // determine that they do not alias...
+          if (O1 != O2) {
+            if (O2 < O1) {    // Ensure that O1 <= O2
+              std::swap(V1, V2);
+              std::swap(O1, O2);
+              std::swap(V1Size, V2Size);
+            }
+
+            // FIXME: This is not correct because we do not handle array
+            // indexing correctly with this check!
+            //if (O1+V1Size <= O2) return NoAlias;
+          }
         }
       }
     }
diff --git a/lib/Analysis/DataStructure/Local.cpp b/lib/Analysis/DataStructure/Local.cpp
index 369b76d..a7751f2 100644
--- a/lib/Analysis/DataStructure/Local.cpp
+++ b/lib/Analysis/DataStructure/Local.cpp
@@ -86,9 +86,9 @@ namespace {
   private:
     // Visitor functions, used to handle each instruction type we encounter...
     friend class InstVisitor<GraphBuilder>;
-    void visitMallocInst(MallocInst &MI) { handleAlloc(MI, DSNode::HeapNode); }
-    void visitAllocaInst(AllocaInst &AI) { handleAlloc(AI, DSNode::AllocaNode);}
-    void handleAlloc(AllocationInst &AI, DSNode::NodeTy NT);
+    void visitMallocInst(MallocInst &MI) { handleAlloc(MI, true); }
+    void visitAllocaInst(AllocaInst &AI) { handleAlloc(AI, false); }
+    void handleAlloc(AllocationInst &AI, bool isHeap);
 
     void visitPHINode(PHINode &PN);
 
@@ -108,8 +108,8 @@ namespace {
     /// createNode - Create a new DSNode, ensuring that it is properly added to
     /// the graph.
     ///
-    DSNode *createNode(DSNode::NodeTy NodeType, const Type *Ty = 0) {
-      DSNode *N = new DSNode(NodeType, Ty, &G);   // Create the node
+    DSNode *createNode(const Type *Ty = 0) {
+      DSNode *N = new DSNode(Ty, &G);   // Create the node
       if (DisableFieldSensitivity) {
         N->foldNodeCompletely();
         if (DSNode *FN = N->getForwardNode())
@@ -194,7 +194,7 @@ DSNodeHandle GraphBuilder::getValueDest(Value &Val) {
         NH = I->second;
       } else {
         // This returns a conservative unknown node for any unhandled ConstExpr
-        return NH = createNode(DSNode::UnknownNode);
+        return NH = createNode()->setUnknownNodeMarker();
       }
       if (NH.getNode() == 0) {  // (getelementptr null, X) returns null
         ScalarMap.erase(V);
@@ -204,7 +204,7 @@ DSNodeHandle GraphBuilder::getValueDest(Value &Val) {
 
     } else if (ConstantIntegral *CI = dyn_cast<ConstantIntegral>(C)) {
       // Random constants are unknown mem
-      return NH = createNode(DSNode::UnknownNode);
+      return NH = createNode()->setUnknownNodeMarker();
     } else {
       assert(0 && "Unknown constant type!");
     }
@@ -213,11 +213,11 @@ DSNodeHandle GraphBuilder::getValueDest(Value &Val) {
   DSNode *N;
   if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
     // Create a new global node for this global variable...
-    N = createNode(DSNode::GlobalNode, GV->getType()->getElementType());
+    N = createNode(GV->getType()->getElementType());
     N->addGlobal(GV);
   } else {
     // Otherwise just create a shadow node
-    N = createNode(DSNode::ShadowNode);
+    N = createNode();
   }
 
   NH.setNode(N);      // Remember that we are pointing to it...
@@ -237,7 +237,7 @@ DSNodeHandle &GraphBuilder::getLink(const DSNodeHandle &node, unsigned LinkNo) {
   DSNodeHandle &Link = Node.getLink(LinkNo);
   if (!Link.getNode()) {
     // If the link hasn't been created yet, make and return a new shadow node
-    Link = createNode(DSNode::ShadowNode);
+    Link = createNode();
   }
   return Link;
 }
@@ -263,8 +263,13 @@ void GraphBuilder::setDestTo(Value &V, const DSNodeHandle &NH) {
 /// Alloca & Malloc instruction implementation - Simply create a new memory
 /// object, pointing the scalar to it.
 ///
-void GraphBuilder::handleAlloc(AllocationInst &AI, DSNode::NodeTy NodeType) {
-  setDestTo(AI, createNode(NodeType));
+void GraphBuilder::handleAlloc(AllocationInst &AI, bool isHeap) {
+  DSNode *N = createNode();
+  if (isHeap)
+    N->setHeapNodeMarker();
+  else
+    N->setAllocaNodeMarker();
+  setDestTo(AI, N);
 }
 
 // PHINode - Make the scalar for the PHI node point to all of the things the
@@ -368,7 +373,7 @@ void GraphBuilder::visitLoadInst(LoadInst &LI) {
   if (Ptr.getNode() == 0) return;
 
   // Make that the node is read from...
-  Ptr.getNode()->NodeType |= DSNode::Read;
+  Ptr.getNode()->setReadMarker();
 
   // Ensure a typerecord exists...
   Ptr.getNode()->mergeTypeInfo(LI.getType(), Ptr.getOffset(), false);
@@ -383,7 +388,7 @@ void GraphBuilder::visitStoreInst(StoreInst &SI) {
   if (Dest.getNode() == 0) return;
 
   // Mark that the node is written to...
-  Dest.getNode()->NodeType |= DSNode::Modified;
+  Dest.getNode()->setModifiedMarker();
 
   // Ensure a typerecord exists...
   Dest.getNode()->mergeTypeInfo(StoredTy, Dest.getOffset());
@@ -426,8 +431,9 @@ void GraphBuilder::visitCallInst(CallInst &CI) {
 
 void GraphBuilder::visitFreeInst(FreeInst &FI) {
   // Mark that the node is written to...
-  getValueDest(*FI.getOperand(0)).getNode()->NodeType
-    |= DSNode::Modified | DSNode::HeapNode;
+  DSNode *N = getValueDest(*FI.getOperand(0)).getNode();
+  N->setModifiedMarker();
+  N->setHeapNodeMarker();
 }
 
 /// Handle casts...
@@ -441,7 +447,7 @@ void GraphBuilder::visitCastInst(CastInst &CI) {
       // to track the fact that the node points to SOMETHING, just something we
       // don't know about.  Make an "Unknown" node.
       //
-      setDestTo(CI, createNode(DSNode::UnknownNode));
+      setDestTo(CI, createNode()->setUnknownNodeMarker());
     }
 }
 
@@ -458,7 +464,7 @@ void GraphBuilder::visitInstruction(Instruction &Inst) {
       CurNode.mergeWith(getValueDest(**I));
 
   if (CurNode.getNode())
-    CurNode.getNode()->NodeType |= DSNode::UnknownNode;
+    CurNode.getNode()->setUnknownNodeMarker();
 }
 
 
diff --git a/lib/Analysis/DataStructure/Printer.cpp b/lib/Analysis/DataStructure/Printer.cpp
index 7f0bf5a..9bde0b7 100644
--- a/lib/Analysis/DataStructure/Printer.cpp
+++ b/lib/Analysis/DataStructure/Printer.cpp
@@ -38,16 +38,19 @@ static std::string getCaption(const DSNode *N, const DSGraph *G) {
     if (N->isArray())
       OS << " array";
   }
-  if (N->NodeType) {
+  if (unsigned NodeType = N->getNodeFlags()) {
     OS << ": ";
-    if (N->NodeType & DSNode::AllocaNode ) OS << "S";
-    if (N->NodeType & DSNode::HeapNode   ) OS << "H";
-    if (N->NodeType & DSNode::GlobalNode ) OS << "G";
-    if (N->NodeType & DSNode::UnknownNode) OS << "U";
-    if (N->NodeType & DSNode::Incomplete ) OS << "I";
-    if (N->NodeType & DSNode::Modified   ) OS << "M";
-    if (N->NodeType & DSNode::Read       ) OS << "R";
-    if (N->NodeType & DSNode::DEAD       ) OS << "<dead>";
+    if (NodeType & DSNode::AllocaNode ) OS << "S";
+    if (NodeType & DSNode::HeapNode   ) OS << "H";
+    if (NodeType & DSNode::GlobalNode ) OS << "G";
+    if (NodeType & DSNode::UnknownNode) OS << "U";
+    if (NodeType & DSNode::Incomplete ) OS << "I";
+    if (NodeType & DSNode::Modified   ) OS << "M";
+    if (NodeType & DSNode::Read       ) OS << "R";
+    if (NodeType & DSNode::MultiObject) OS << "m";
+#ifndef NDEBUG
+    if (NodeType & DSNode::DEAD       ) OS << "<dead>";
+#endif
     OS << "\n";
   }