Disallow null as a named metadata operand.

Make MDNode::destroy private.
Fix the one thing that used MDNode::destroy, outside of MDNode itself.

One should never delete or destroy an MDNode explicitly. MDNodes
implicitly go away when there are no references to them (implementation
details aside).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109028 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 4 insertions, 9 deletions

diff --git a/lib/VMCore/AsmWriter.cpp b/lib/VMCore/AsmWriter.cpp
index c371ab9..7d51be1 100644
--- a/lib/VMCore/AsmWriter.cpp
+++ b/lib/VMCore/AsmWriter.cpp
@@ -638,10 +638,8 @@ void SlotTracker::processModule() {
          I = TheModule->named_metadata_begin(),
          E = TheModule->named_metadata_end(); I != E; ++I) {
     const NamedMDNode *NMD = I;
-    for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
-      if (MDNode *MD = NMD->getOperand(i))
-        CreateMetadataSlot(MD);
-    }
+    for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
+      CreateMetadataSlot(NMD->getOperand(i));
   }
 
   // Add all the unnamed functions to the table.
@@ -1424,10 +1422,7 @@ void AssemblyWriter::printNamedMDNode(const NamedMDNode *NMD) {
   Out << "!" << NMD->getName() << " = !{";
   for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
     if (i) Out << ", ";
-    if (MDNode *MD = NMD->getOperand(i))
-      Out << '!' << Machine.getMetadataSlot(MD);
-    else
-      Out << "null";
+    Out << '!' << Machine.getMetadataSlot(NMD->getOperand(i));
   }
   Out << "}\n";
 }
diff --git a/lib/VMCore/Metadata.cpp b/lib/VMCore/Metadata.cpp
index a89cffd..cc4a68e 100644
--- a/lib/VMCore/Metadata.cpp
+++ b/lib/VMCore/Metadata.cpp
@@ -389,7 +389,7 @@ unsigned NamedMDNode::getNumOperands() const {
 /// getOperand - Return specified operand.
 MDNode *NamedMDNode::getOperand(unsigned i) const {
   assert(i < getNumOperands() && "Invalid Operand number!");
-  return dyn_cast_or_null<MDNode>(&*getNMDOps(Operands)[i]);
+  return dyn_cast<MDNode>(&*getNMDOps(Operands)[i]);
 }
 
 /// addOperand - Add metadata Operand.