--- a/llvm/tools/dsymutil/DwarfLinker.cpp
+++ b/llvm/tools/dsymutil/DwarfLinker.cpp
@@ -1489,8 +1489,12 @@
   uint64_t RefOffset = *RefValue.getAsReference(&Unit);
 
   if ((RefCU = getUnitForOffset(Units, RefOffset)))
-    if (const auto *RefDie = RefCU->getOrigUnit().getDIEForOffset(RefOffset))
-      return RefDie;
+    if (const auto *RefDie = RefCU->getOrigUnit().getDIEForOffset(RefOffset)) {
+      // In a file with broken references, an attribute might point to a NULL
+      // DIE.
+      if(!RefDie->isNULL())
+        return RefDie;
+    }
 
   Linker.reportWarning("could not find referenced DIE", &Unit, &DIE);
   return nullptr;