diff --git a/lld/ELF/Symbols.h b/lld/ELF/Symbols.h
--- a/lld/ELF/Symbols.h
+++ b/lld/ELF/Symbols.h
@@ -482,6 +482,11 @@
   IsPreemptible = Old.IsPreemptible;
   ScriptDefined = Old.ScriptDefined;
 
+  // Symbol length is computed lazily. If we already know a symbol length,
+  // propagate it.
+  if (NameData == New.NameData && NameSize == 0 && New.NameSize != 0)
+    NameSize = New.NameSize;
+
   // Print out a log message if --trace-symbol was specified.
   // This is for debugging.
   if (Traced)