From d542049596456a0378a6a05a6b0f4289ea380215 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sun, 4 Oct 2020 17:27:38 +0200
Subject: [PATCH] LibJS: Avoid StringImpl refcount churn when hashing
 StringOrSymbol

Add a StringOrSymbol::hash() helper function so we can compute the hash
without having to construct a temporary String.
---
 Libraries/LibJS/Runtime/StringOrSymbol.h | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/Libraries/LibJS/Runtime/StringOrSymbol.h b/Libraries/LibJS/Runtime/StringOrSymbol.h
index 01ca65b6ce..b8d031affb 100644
--- a/Libraries/LibJS/Runtime/StringOrSymbol.h
+++ b/Libraries/LibJS/Runtime/StringOrSymbol.h
@@ -135,6 +135,13 @@ public:
         return *this;
     }
 
+    unsigned hash() const
+    {
+        if (is_string())
+            return static_cast<const StringImpl*>(m_ptr)->hash();
+        return ptr_hash(as_symbol());
+    }
+
 private:
     ALWAYS_INLINE u64 bits() const
     {
@@ -155,10 +162,6 @@ template<>
 struct AK::Traits<JS::StringOrSymbol> : public GenericTraits<JS::StringOrSymbol> {
     static unsigned hash(const JS::StringOrSymbol& key)
     {
-        if (key.is_string())
-            return key.as_string().hash();
-        if (key.is_symbol())
-            return ptr_hash(key.as_symbol());
-        return 0;
+        return key.hash();
     }
 };