Add a way to replace a field inside a metadata node. This can be

used to incrementally update a created node without needing a
temporary node and RAUW.

llvm-svn: 150571

llvm/include/llvm/Metadata.h

@@ -135,6 +135,9 @@ public:
   /// deleteTemporary - Deallocate a node created by getTemporary. The
   /// node must not have any users.
   static void deleteTemporary(MDNode *N);
+
+  /// replaceOperandWith - Replace a specific operand.
+  void replaceOperandWith(unsigned i, Value *NewVal);
   
   /// getOperand - Return specified operand.
   Value *getOperand(unsigned i) const;

llvm/lib/VMCore/Metadata.cpp

@@ -87,6 +87,11 @@ static MDNodeOperand *getOperandPtr(MDNode *N, unsigned Op) {
   return reinterpret_cast<MDNodeOperand*>(N+1)+Op;
 }
 
+void MDNode::replaceOperandWith(unsigned i, Value *Val) {
+  MDNodeOperand *Op = getOperandPtr(this, i);
+  replaceOperand(Op, Val);
+}
+
 MDNode::MDNode(LLVMContext &C, ArrayRef<Value*> Vals, bool isFunctionLocal)
 : Value(Type::getMetadataTy(C), Value::MDNodeVal) {
   NumOperands = Vals.size();