From b00b461b317eaed1cf027731ea8aaec3fe857edc Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Fri, 8 Oct 2021 01:32:12 +0200
Subject: [PATCH] LibJS: Pre-size a HashTable in
 function_declaration_instantiation()

The dynamic resizing of this hash table was showing up in profiles.
Since we have an idea of how big it will get, use ensure_capacity().
---
 Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.cpp b/Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.cpp
index ce15244e39..e998236294 100644
--- a/Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.cpp
+++ b/Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.cpp
@@ -287,6 +287,8 @@ ThrowCompletionOr<void> ECMAScriptFunctionObject::function_declaration_instantia
     Environment* var_environment;
 
     HashTable<FlyString> instantiated_var_names;
+    if (scope_body)
+        instantiated_var_names.ensure_capacity(scope_body->var_declaration_count());
 
     if (!has_parameter_expressions) {
         if (scope_body) {