--- a/js/src/vm/PropertyKey.h
+++ b/js/src/vm/PropertyKey.h
@@ -13,28 +13,38 @@
 
 #include "js/HashTable.h"   // js::DefaultHasher
 #include "js/Id.h"          // JS::PropertyKey
 #include "vm/StringType.h"  // JSAtom::hash
 #include "vm/SymbolType.h"  // JS::Symbol::hash
 
 namespace js {
 
-static MOZ_ALWAYS_INLINE js::HashNumber HashPropertyKey(PropertyKey key) {
+static MOZ_ALWAYS_INLINE HashNumber HashPropertyKey(PropertyKey key) {
   // HashGeneric alone would work, but bits of atom and symbol addresses
   // could then be recovered from the hash code. See bug 1330769.
   if (MOZ_LIKELY(key.isAtom())) {
     return key.toAtom()->hash();
   }
   if (key.isSymbol()) {
     return key.toSymbol()->hash();
   }
   return mozilla::HashGeneric(key.asBits);
 }
 
+// Like HashPropertyKey but optimized for callers that only use atom or symbol
+// keys.
+static MOZ_ALWAYS_INLINE HashNumber
+HashAtomOrSymbolPropertyKey(PropertyKey key) {
+  if (MOZ_LIKELY(key.isAtom())) {
+    return key.toAtom()->hash();
+  }
+  return key.toSymbol()->hash();
+}
+
 }  // namespace js
 
 namespace mozilla {
 
 template <>
 struct DefaultHasher<JS::PropertyKey> {
   using Lookup = JS::PropertyKey;
   static HashNumber hash(JS::PropertyKey key) {