Formalize MDNode's function-localness:

- an MDNode is designated as function-local when created, and continues to be even if its operands are modified not to refer to function-local IR
- function-localness is designated via lowest bit in SubclassData
- getLocalFunction() descends MDNode tree to see if it is consistently function-local

Add verification of MDNodes to checks that MDNodes are consistently function-local.
Update AsmWriter to use isFunctionLocal().

llvm-svn: 91708

1 files changed, 4 insertions, 5 deletions

diff --git a/llvm/lib/VMCore/AsmWriter.cpp b/llvm/lib/VMCore/AsmWriter.cpp
index c765d968fcd..13905ea1906 100644
--- a/llvm/lib/VMCore/AsmWriter.cpp
+++ b/llvm/lib/VMCore/AsmWriter.cpp
@@ -813,10 +813,9 @@ void SlotTracker::CreateFunctionSlot(const Value *V) {
 void SlotTracker::CreateMetadataSlot(const MDNode *N) {
   assert(N && "Can't insert a null Value into SlotTracker!");
 
-  // Don't insert if N contains an instruction.
-  for (unsigned i = 0, e = N->getNumElements(); i != e; ++i)
-    if (N->getElement(i) && isa<Instruction>(N->getElement(i)))
-      return;
+  // Don't insert if N is a function-local metadata.
+  if (N->isFunctionLocal())
+    return;
 
   ValueMap::iterator I = mdnMap.find(N);
   if (I != mdnMap.end())
@@ -1232,7 +1231,7 @@ static void WriteAsOperandInternal(raw_ostream &Out, const Value *V,
   }
 
   if (const MDNode *N = dyn_cast<MDNode>(V)) {
-    if (Machine->getMetadataSlot(N) == -1) {
+    if (N->isFunctionLocal()) {
       // Print metadata inline, not via slot reference number.
       Out << "!{";
       for (unsigned mi = 0, me = N->getNumElements(); mi != me; ++mi) {