Keep track of metadata used by other metadata.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78012 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 52 insertions, 4 deletions

diff --git a/lib/VMCore/Metadata.cpp b/lib/VMCore/Metadata.cpp
index f548e54..b44441f 100644
--- a/lib/VMCore/Metadata.cpp
+++ b/lib/VMCore/Metadata.cpp
@@ -19,6 +19,34 @@
 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
 //
 MDString *MDString::get(LLVMContext &Context, const StringRef &Str) {
@@ -38,8 +66,14 @@ MDString *MDString::get(LLVMContext &Context, const StringRef &Str) {
 //
 MDNode::MDNode(Value*const* Vals, unsigned NumVals)
   : MetadataBase(Type::MetadataTy, Value::MDNodeVal) {
-  for (unsigned i = 0; i != NumVals; ++i)
+  NumOperands = 0;
+  resizeOperands(NumVals);
+  for (unsigned i = 0; i != NumVals; ++i) {
+    // Only record metadata uses.
+    if (MetadataBase *MB = dyn_cast_or_null<MetadataBase>(Vals[i]))
+      OperandList[NumOperands++] = MB;
     Node.push_back(WeakVH(Vals[i]));
+  }
 }
 
 void MDNode::Profile(FoldingSetNodeID &ID) const {
@@ -71,6 +105,15 @@ 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();
+  Node.clear();
+}
+
+MDNode::~MDNode() {
+  dropAllReferences();
+}
 //===----------------------------------------------------------------------===//
 //NamedMDNode implementation
 //
@@ -78,8 +121,14 @@ NamedMDNode::NamedMDNode(const Twine &N, MetadataBase*const* MDs,
                          unsigned NumMDs, Module *ParentModule)
   : MetadataBase(Type::MetadataTy, Value::NamedMDNodeVal), Parent(0) {
   setName(N);
-  for (unsigned i = 0; i != NumMDs; ++i)
+  NumOperands = 0;
+  resizeOperands(NumMDs);
+
+  for (unsigned i = 0; i != NumMDs; ++i) {
+    if (MDs[i])
+      OperandList[NumOperands++] = MDs[i];
     Node.push_back(WeakMetadataVH(MDs[i]));
+  }
   if (ParentModule)
     ParentModule->getNamedMDList().push_back(this);
 }
@@ -87,13 +136,12 @@ NamedMDNode::NamedMDNode(const Twine &N, MetadataBase*const* MDs,
 /// eraseFromParent - Drop all references and remove the node from parent
 /// module.
 void NamedMDNode::eraseFromParent() {
-  dropAllReferences();
   getParent()->getNamedMDList().erase(this);
 }
 
 /// dropAllReferences - Remove all uses and clear node vector.
 void NamedMDNode::dropAllReferences() {
-  // FIXME: Update metadata use list.
+  User::dropAllReferences();
   Node.clear();
 }