Derive metadata hierarchy from Value instead of User.

llvm-svn: 84801

include/llvm/LLVMContext.h

@@ -33,7 +33,6 @@ class LLVMContext {
 public:
   LLVMContextImpl* const pImpl;
   MetadataContext &getMetadata();
-  bool RemoveDeadMetadata();
   LLVMContext();
   ~LLVMContext();
 };

include/llvm/Metadata.h

@@ -16,7 +16,7 @@
 #ifndef LLVM_METADATA_H
 #define LLVM_METADATA_H
 
-#include "llvm/User.h"
+#include "llvm/Value.h"
 #include "llvm/Type.h"
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/ADT/SmallVector.h"
@@ -33,17 +33,11 @@ class LLVMContext;
 
 //===----------------------------------------------------------------------===//
 // MetadataBase  - A base class for MDNode, MDString and NamedMDNode.
-class MetadataBase : public User {
-private:
-  /// ReservedSpace - The number of operands actually allocated.  NumOperands is
-  /// the number actually in use.
-  unsigned ReservedSpace;
-
+class MetadataBase : public Value {
 protected:
   MetadataBase(const Type *Ty, unsigned scid)
-    : User(Ty, scid, NULL, 0), ReservedSpace(0) {}
+    : Value(Ty, scid) {}
 
-  void resizeOperands(unsigned NumOps);
 public:
 
   /// Methods for support type inquiry through isa, cast, and dyn_cast:
@@ -60,8 +54,6 @@ public:
 /// MDString is always unnamd.
 class MDString : public MetadataBase {
   MDString(const MDString &);            // DO NOT IMPLEMENT
-  void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
-  unsigned getNumOperands();             // DO NOT IMPLEMENT
 
   StringRef Str;
 protected:
@@ -69,10 +61,6 @@ protected:
     : MetadataBase(Type::getMetadataTy(C), Value::MDStringVal), Str(begin, l) {}
 
 public:
-  // Do not allocate any space for operands.
-  void *operator new(size_t s) {
-    return User::operator new(s, 0);
-  }
   static MDString *get(LLVMContext &Context, const StringRef &Str);
   
   StringRef getString() const { return Str; }
@@ -102,9 +90,6 @@ public:
 /// MDNode is always unnamed.
 class MDNode : public MetadataBase, public FoldingSetNode {
   MDNode(const MDNode &);                // DO NOT IMPLEMENT
-  void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
-  // getNumOperands - Make this only available for private uses.
-  unsigned getNumOperands() { return User::getNumOperands();  }
 
   friend class ElementVH;
   // Use CallbackVH to hold MDNOde elements.
@@ -131,17 +116,10 @@ class MDNode : public MetadataBase, public FoldingSetNode {
 protected:
   explicit MDNode(LLVMContext &C, Value *const *Vals, unsigned NumVals);
 public:
-  // Do not allocate any space for operands.
-  void *operator new(size_t s) {
-    return User::operator new(s, 0);
-  }
   // Constructors and destructors.
   static MDNode *get(LLVMContext &Context, 
                      Value *const *Vals, unsigned NumVals);
 
-  /// dropAllReferences - Remove all uses and clear node vector.
-  void dropAllReferences();
-
   /// ~MDNode - Destroy MDNode.
   ~MDNode();
   
@@ -193,9 +171,6 @@ class NamedMDNode : public MetadataBase, public ilist_node<NamedMDNode> {
   friend class LLVMContextImpl;
 
   NamedMDNode(const NamedMDNode &);      // DO NOT IMPLEMENT
-  void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
-  // getNumOperands - Make this only available for private uses.
-  unsigned getNumOperands() { return User::getNumOperands();  }
 
   Module *Parent;
   SmallVector<WeakMetadataVH, 4> Node;
@@ -206,10 +181,6 @@ protected:
   explicit NamedMDNode(LLVMContext &C, const Twine &N, MetadataBase*const *Vals, 
                        unsigned NumVals, Module *M = 0);
 public:
-  // Do not allocate any space for operands.
-  void *operator new(size_t s) {
-    return User::operator new(s, 0);
-  }
   static NamedMDNode *Create(LLVMContext &C, const Twine &N, 
                              MetadataBase *const *MDs, 
                              unsigned NumMDs, Module *M = 0) {
@@ -245,8 +216,6 @@ public:
 
   /// addElement - Add metadata element.
   void addElement(MetadataBase *M) {
-    resizeOperands(NumOperands + 1);
-    OperandList[NumOperands++] = M;
     Node.push_back(WeakMetadataVH(M));
   }
 

lib/Transforms/IPO/GlobalDCE.cpp

@@ -149,9 +149,6 @@ bool GlobalDCE::runOnModule(Module &M) {
   // Make sure that all memory is released
   AliveGlobals.clear();
 
-  // Remove dead metadata.
-  // FIXME - Enable this.
-  // Changed |= M.getContext().RemoveDeadMetadata();
   return Changed;
 }
 

lib/Transforms/IPO/StripSymbols.cpp

@@ -250,8 +250,6 @@ static bool StripDebugInfo(Module &M) {
   if (NMD)
     NMD->eraseFromParent();
 
-  // Remove dead metadata.
-  M.getContext().RemoveDeadMetadata();
   return true;
 }
 

lib/VMCore/LLVMContext.cpp

@@ -45,32 +45,6 @@ GetElementPtrConstantExpr::GetElementPtrConstantExpr
     OperandList[i+1] = IdxList[i];
 }
 
-bool LLVMContext::RemoveDeadMetadata() {
-  std::vector<WeakVH> DeadMDNodes;
-  bool Changed = false;
-  while (1) {
-
-    for (FoldingSet<MDNode>::iterator 
-           I = pImpl->MDNodeSet.begin(),
-           E = pImpl->MDNodeSet.end(); I != E; ++I) {
-      MDNode *N = &(*I);
-      if (N->use_empty()) 
-        DeadMDNodes.push_back(WeakVH(N));
-    }
-    
-    if (DeadMDNodes.empty())
-      return Changed;
-
-    while (!DeadMDNodes.empty()) {
-      Value *V = DeadMDNodes.back(); DeadMDNodes.pop_back();
-      if (const MDNode *N = dyn_cast_or_null<MDNode>(V))
-        if (N->use_empty())
-          delete N;
-    }
-  }
-  return Changed;
-}
-
 MetadataContext &LLVMContext::getMetadata() {
   return pImpl->TheMetadata;
 }

lib/VMCore/LLVMContextImpl.h

@@ -203,9 +203,6 @@ public:
     AggZeroConstants.freeConstants();
     NullPtrConstants.freeConstants();
     UndefValueConstants.freeConstants();
-    for (FoldingSet<MDNode>::iterator I = MDNodeSet.begin(), 
-           E = MDNodeSet.end(); I != E; ++I)
-      I->dropAllReferences();
     for (IntMapTy::iterator I = IntConstants.begin(), E = IntConstants.end(); 
          I != E; ++I) {
       if (I->second->use_empty())
@@ -216,6 +213,7 @@ public:
       if (I->second->use_empty())
         delete I->second;
     }
+    MDNodeSet.clear();
   }
 };
 

lib/VMCore/Metadata.cpp

@@ -23,30 +23,6 @@ using namespace llvm;
 // MetadataBase implementation.
 //
 
-/// resizeOperands - Metadata keeps track of other metadata uses using 
-/// OperandList. Resize this list to hold anticipated number of metadata
-/// operands.
-void MetadataBase::resizeOperands(unsigned NumOps) {
-  unsigned e = getNumOperands();
-  if (NumOps == 0) {
-    NumOps = e*2;
-    if (NumOps < 2) NumOps = 2;  
-  } else if (NumOps > NumOperands) {
-    // No resize needed.
-    if (ReservedSpace >= NumOps) return;
-  } else if (NumOps == NumOperands) {
-    if (ReservedSpace == NumOps) return;
-  } else {
-    return;
-  }
-
-  ReservedSpace = NumOps;
-  Use *OldOps = OperandList;
-  Use *NewOps = allocHungoffUses(NumOps);
-  std::copy(OldOps, OldOps + e, NewOps);
-  OperandList = NewOps;
-  if (OldOps) Use::zap(OldOps, OldOps + e, true);
-}
 //===----------------------------------------------------------------------===//
 // MDString implementation.
 //
@@ -65,20 +41,11 @@ MDString *MDString::get(LLVMContext &Context, const StringRef &Str) {
 //
 MDNode::MDNode(LLVMContext &C, Value *const *Vals, unsigned NumVals)
   : MetadataBase(Type::getMetadataTy(C), Value::MDNodeVal) {
-  NumOperands = 0;
-  resizeOperands(NumVals);
   NodeSize = NumVals;
   Node = new ElementVH[NodeSize];
   ElementVH *Ptr = Node;
-  for (unsigned i = 0; i != NumVals; ++i) {
-    // Only record metadata uses.
-    if (MetadataBase *MB = dyn_cast_or_null<MetadataBase>(Vals[i]))
-      OperandList[NumOperands++] = MB;
-    else if(Vals[i] && 
-            Vals[i]->getType()->getTypeID() == Type::MetadataTyID)
-      OperandList[NumOperands++] = Vals[i];
+  for (unsigned i = 0; i != NumVals; ++i) 
     *Ptr++ = ElementVH(Vals[i], this);
-  }
 }
 
 void MDNode::Profile(FoldingSetNodeID &ID) const {
@@ -109,19 +76,14 @@ MDNode *MDNode::get(LLVMContext &Context, Value*const* Vals, unsigned NumVals) {
   return N;
 }
 
-/// dropAllReferences - Remove all uses and clear node vector.
-void MDNode::dropAllReferences() {
-  User::dropAllReferences();
-  delete [] Node;
-  Node = NULL;
-}
-
+/// ~MDNode - Destroy MDNode.
 MDNode::~MDNode() {
   {
     LLVMContextImpl *pImpl = getType()->getContext().pImpl;
     pImpl->MDNodeSet.RemoveNode(this);
   }
-  dropAllReferences();
+  delete [] Node;
+  Node = NULL;
 }
 
 // Replace value from this node's element list.
@@ -148,27 +110,6 @@ void MDNode::replaceElement(Value *From, Value *To) {
   // Remove "this" from the context map. 
   pImpl->MDNodeSet.RemoveNode(this);
 
-  // MDNode only lists metadata elements in operand list, because MDNode
-  // used by MDNode is considered a valid use. However on the side, MDNode
-  // using a non-metadata value is not considered a "use" of non-metadata
-  // value.
-  SmallVector<unsigned, 4> OpIndexes;
-  unsigned OpIndex = 0;
-  for (User::op_iterator OI = op_begin(), OE = op_end();
-       OI != OE; ++OI, OpIndex++) {
-    if (*OI == From)
-      OpIndexes.push_back(OpIndex);
-  }
-  if (MetadataBase *MDTo = dyn_cast_or_null<MetadataBase>(To)) {
-    for (SmallVector<unsigned, 4>::iterator OI = OpIndexes.begin(),
-           OE = OpIndexes.end(); OI != OE; ++OI)
-      setOperand(*OI, MDTo);
-  } else {
-    for (SmallVector<unsigned, 4>::iterator OI = OpIndexes.begin(),
-           OE = OpIndexes.end(); OI != OE; ++OI)
-      setOperand(*OI, 0);
-  }
-
   // Replace From element(s) in place.
   for (SmallVector<unsigned, 4>::iterator I = Indexes.begin(), E = Indexes.end(); 
        I != E; ++I) {
@@ -207,14 +148,10 @@ NamedMDNode::NamedMDNode(LLVMContext &C, const Twine &N,
                          unsigned NumMDs, Module *ParentModule)
   : MetadataBase(Type::getMetadataTy(C), Value::NamedMDNodeVal), Parent(0) {
   setName(N);
-  NumOperands = 0;
-  resizeOperands(NumMDs);
 
-  for (unsigned i = 0; i != NumMDs; ++i) {
-    if (MDs[i])
-      OperandList[NumOperands++] = MDs[i];
+  for (unsigned i = 0; i != NumMDs; ++i)
     Node.push_back(WeakMetadataVH(MDs[i]));
-  }
+
   if (ParentModule)
     ParentModule->getNamedMDList().push_back(this);
 }
@@ -236,7 +173,6 @@ void NamedMDNode::eraseFromParent() {
 
 /// dropAllReferences - Remove all uses and clear node vector.
 void NamedMDNode::dropAllReferences() {
-  User::dropAllReferences();
   Node.clear();
 }