From 67c32a98315f785a9ec9d531c1f571a0196c7463 Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Sun, 18 Jan 2015 16:17:27 +0000
Subject: Vendor import of llvm RELEASE_360/rc1 tag r226102 (effectively, 3.6.0
 RC1): https://llvm.org/svn/llvm-project/llvm/tags/RELEASE_360/rc1@226102

---
 lib/IR/MetadataTracking.cpp | 58 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 lib/IR/MetadataTracking.cpp

(limited to 'lib/IR/MetadataTracking.cpp')

diff --git a/lib/IR/MetadataTracking.cpp b/lib/IR/MetadataTracking.cpp
new file mode 100644
index 0000000000000..ba97ca033a454
--- /dev/null
+++ b/lib/IR/MetadataTracking.cpp
@@ -0,0 +1,58 @@
+//===- MetadataTracking.cpp - Implement metadata tracking -----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements Metadata tracking.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/MetadataTracking.h"
+#include "llvm/IR/Metadata.h"
+
+using namespace llvm;
+
+ReplaceableMetadataImpl *ReplaceableMetadataImpl::get(Metadata &MD) {
+  if (auto *N = dyn_cast<MDNode>(&MD)) {
+    if (auto *U = dyn_cast<UniquableMDNode>(N))
+      return U->ReplaceableUses.get();
+    return cast<MDNodeFwdDecl>(N);
+  }
+  return dyn_cast<ValueAsMetadata>(&MD);
+}
+
+bool MetadataTracking::track(void *Ref, Metadata &MD, OwnerTy Owner) {
+  assert(Ref && "Expected live reference");
+  assert((Owner || *static_cast<Metadata **>(Ref) == &MD) &&
+         "Reference without owner must be direct");
+  if (auto *R = ReplaceableMetadataImpl::get(MD)) {
+    R->addRef(Ref, Owner);
+    return true;
+  }
+  return false;
+}
+
+void MetadataTracking::untrack(void *Ref, Metadata &MD) {
+  assert(Ref && "Expected live reference");
+  if (auto *R = ReplaceableMetadataImpl::get(MD))
+    R->dropRef(Ref);
+}
+
+bool MetadataTracking::retrack(void *Ref, Metadata &MD, void *New) {
+  assert(Ref && "Expected live reference");
+  assert(New && "Expected live reference");
+  assert(Ref != New && "Expected change");
+  if (auto *R = ReplaceableMetadataImpl::get(MD)) {
+    R->moveRef(Ref, New, MD);
+    return true;
+  }
+  return false;
+}
+
+bool MetadataTracking::isReplaceable(const Metadata &MD) {
+  return ReplaceableMetadataImpl::get(const_cast<Metadata &>(MD));
+}
-- 
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