IR: Allow temporary nodes to become uniqued or distinct

Add `MDNode::replaceWithUniqued()` and `MDNode::replaceWithDistinct()`,
which mutate temporary nodes to become uniqued or distinct.  On uniquing
collisions, the unique version is returned and the node is deleted.

This takes advantage of temporary nodes being folded back in, and should
let me clean up some awkward logic in `MapMetadata()`.

llvm-svn: 226510

1 files changed, 27 insertions, 0 deletions

diff --git a/llvm/lib/IR/Metadata.cpp b/llvm/lib/IR/Metadata.cpp
index 0e258623368..822a9f5237c 100644
--- a/llvm/lib/IR/Metadata.cpp
+++ b/llvm/lib/IR/Metadata.cpp
@@ -436,6 +436,33 @@ unsigned UniquableMDNode::countUnresolvedOperands() const {
   return NumUnresolved;
 }
 
+void UniquableMDNode::makeUniqued() {
+  assert(isTemporary() && "Expected this to be temporary");
+  assert(!isResolved() && "Expected this to be unresolved");
+
+  // Make this 'uniqued'.
+  Storage = Uniqued;
+  if (unsigned NumUnresolved = countUnresolvedOperands())
+    SubclassData32 = NumUnresolved;
+  else
+    resolve();
+
+  assert(isUniqued() && "Expected this to be uniqued");
+}
+
+void UniquableMDNode::makeDistinct() {
+  assert(isTemporary() && "Expected this to be temporary");
+  assert(!isResolved() && "Expected this to be unresolved");
+
+  // Pretend to be uniqued, resolve the node, and then store in distinct table.
+  Storage = Uniqued;
+  resolve();
+  storeDistinctInContext();
+
+  assert(isDistinct() && "Expected this to be distinct");
+  assert(isResolved() && "Expected this to be resolved");
+}
+
 void UniquableMDNode::resolve() {
   assert(isUniqued() && "Expected this to be uniqued");
   assert(!isResolved() && "Expected this to be unresolved");