Bitcode: Add METADATA_NODE and METADATA_VALUE

This reflects the typelessness of `Metadata` in the bitcode format,
removing types from all metadata operands.

`METADATA_VALUE` represents a `ValueAsMetadata`, and always has two
fields: the type and the value.

`METADATA_NODE` represents an `MDNode`, and unlike `METADATA_OLD_NODE`,
doesn't store types.  It stores operands at their ID+1 so that `0` can
reference `nullptr` operands.

Part of PR21532.

llvm-svn: 224073

1 files changed, 1 insertions, 7 deletions

diff --git a/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp b/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
index cae20a86af9..c90dfbd776a 100644
--- a/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
+++ b/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
@@ -521,15 +521,9 @@ void ValueEnumerator::EnumerateNamedMDNode(const NamedMDNode *MD) {
 void ValueEnumerator::EnumerateMDNodeOperands(const MDNode *N) {
   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
     Metadata *MD = N->getOperand(i);
-    if (!MD) {
-      EnumerateType(Type::getVoidTy(N->getContext()));
+    if (!MD)
       continue;
-    }
     assert(!isa<LocalAsMetadata>(MD) && "MDNodes cannot be function-local");
-    if (auto *C = dyn_cast<ConstantAsMetadata>(MD)) {
-      EnumerateValue(C->getValue());
-      continue;
-    }
     EnumerateMetadata(MD);
   }
 }