Ensure MDNode used as key in metadata linking map cannot be RAUWed

[oota-llvm.git] / lib / Linker / IRMover.cpp

diff --git a/lib/Linker/IRMover.cpp b/lib/Linker/IRMover.cpp
index fa6e37517fc4d766386a9259a4a40ef345712589..2e09d78a6906c1247d175e2a7b0ab95b80d6bc12 100644 (file)
--- a/lib/Linker/IRMover.cpp
+++ b/lib/Linker/IRMover.cpp
@@ -524,6 +524,23 @@ public:
       ValueMapperFlags = ValueMapperFlags | RF_HaveUnmaterializedMetadata;
   }
 
+  ~IRLinker() {
+    // In the case where we are not linking metadata, we unset the CanReplace
+    // flag on all temporary metadata in the MetadataToIDs map to ensure
+    // none was replaced while being a map key. Now that we are destructing
+    // the map, set the flag back to true, so that it is replaceable during
+    // metadata linking.
+    if (!shouldLinkMetadata()) {
+      for (auto MDI : MetadataToIDs) {
+        Metadata *MD = const_cast<Metadata *>(MDI.first);
+        MDNode *Node = dyn_cast<MDNode>(MD);
+        assert((Node && Node->isTemporary()) &&
+               "Found non-temp metadata in map when not linking metadata");
+        Node->setCanReplace(true);
+      }
+    }
+  }
+
   bool run();
   Value *materializeDeclFor(Value *V, bool ForAlias);
   void materializeInitFor(GlobalValue *New, GlobalValue *Old, bool ForAlias);