Improve global object setup and access performance (#1280)

Jint/Collections/HybridDictionary.cs

@@ -75,6 +75,22 @@ public bool TryGetValue(Key key, out TValue value)
             return false;
         }
 
+        public void SetOrUpdateValue<TState>(Key key, Func<TValue, TState, TValue> updater, TState state)
+        {
+            if (_dictionary != null)
+            {
+                _dictionary.SetOrUpdateValue(key, updater, state);
+            }
+            else if (_list != null)
+            {
+                _list.SetOrUpdateValue(key, updater, state);
+            }
+            else
+            {
+                _list = new ListDictionary<TValue>(key, updater(default, state), _checkExistingKeys);
+            }
+        }
+
         private void SwitchToDictionary(Key key, TValue value)
         {
             var dictionary = new StringDictionarySlim<TValue>(InitialDictionarySize);
@@ -122,19 +138,8 @@ public void Add(Key key, TValue value)
 
         public void Clear()
         {
-            if (_dictionary != null)
-            {
-                var dictionary = _dictionary;
-                _dictionary = null;
-                dictionary.Clear();
-            }
-
-            if (_list != null)
-            {
-                var cachedList = _list;
-                _list = null;
-                cachedList.Clear();
-            }
+            _dictionary?.Clear();
+            _list?.Clear();
         }
 
         public bool ContainsKey(Key key)
@@ -144,10 +149,9 @@ public bool ContainsKey(Key key)
                 return _dictionary.ContainsKey(key);
             }
 
-            var cachedList = _list;
-            if (cachedList != null)
+            if (_list != null)
             {
-                return cachedList.ContainsKey(key);
+                return _list.ContainsKey(key);
             }
 
             return false;
@@ -193,7 +197,7 @@ public bool Remove(Key key)
 
             return _list != null && _list.Remove(key);
         }
-        
+
         /// <summary>
         /// Optimization when no need to check for existing items.
         /// </summary>

Jint/Collections/ListDictionary.cs

@@ -17,7 +17,7 @@ public ListDictionary(Key key, TValue value, bool checkExistingKeys)
             _checkExistingKeys = checkExistingKeys;
             _head = new DictionaryNode
             {
-                Key = key, 
+                Key = key,
                 Value = value
             };
             _count = 1;
@@ -75,6 +75,24 @@ public bool TryGetValue(Key key, out TValue value)
             return false;
         }
 
+        public void SetOrUpdateValue<TState>(Key key, Func<TValue, TState, TValue> updater, TState state)
+        {
+            DictionaryNode last = null;
+            DictionaryNode node;
+            for (node = _head; node != null; node = node.Next)
+            {
+                if (node.Key == key)
+                {
+                    node.Value = updater(node.Value, state);
+                    return;
+                }
+
+                last = node;
+            }
+
+            AddNode(key, updater(default, state), last);
+        }
+
         public int Count
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]

Jint/Collections/StringDictionarySlim.cs

@@ -141,7 +141,13 @@ public bool Remove(Key key)
             return false;
         }
 
-       // Not safe for concurrent _reads_ (at least, if either of them add)
+        public void SetOrUpdateValue<TState>(Key key, Func<TValue, TState, TValue> updater, TState state)
+        {
+            ref var currentValue = ref GetOrAddValueRef(key);
+            currentValue = updater(currentValue, state);
+        }
+
+        // Not safe for concurrent _reads_ (at least, if either of them add)
         // For concurrent reads, prefer TryGetValue(key, out value)
         /// <summary>
         /// Gets the value for the specified key, or, if the key is not present,
@@ -222,7 +228,7 @@ private Entry[] Resize()
 
             return entries;
         }
-        
+
         /// <summary>
         /// Gets an enumerator over the dictionary
         /// </summary>
@@ -286,7 +292,7 @@ void IEnumerator.Reset()
 
             public void Dispose() { }
         }
-        
+
         internal static class HashHelpers
         {
             internal static readonly int[] SizeOneIntArray = new int[1];

Jint/Native/Global/GlobalObject.cs

@@ -21,8 +21,6 @@ public sealed class GlobalObject : ObjectInstance
             Realm realm) : base(engine)
         {
             _realm = realm;
-            // this is implementation dependent, and only to pass some unit tests
-            _prototype = realm.Intrinsics.Object.PrototypeObject;
         }
 
         protected override void Initialize()
@@ -798,14 +796,14 @@ internal PropertyDescriptor GetOwnProperty(Key property)
             return descriptor ?? PropertyDescriptor.Undefined;
         }
 
-        internal bool Set(Key property, JsValue value)
+        internal bool SetFromMutableBinding(Key property, JsValue value)
         {
             // here we are called only from global environment record context
             // we can take some shortcuts to be faster
 
             if (!_properties!.TryGetValue(property, out var existingDescriptor))
             {
-                _properties[property] = new PropertyDescriptor(value, PropertyFlag.ConfigurableEnumerableWritable);
+                _properties[property] = new PropertyDescriptor(value, PropertyFlag.ConfigurableEnumerableWritable | PropertyFlag.MutableBinding);
                 return true;
             }
 

Jint/Native/Object/ObjectInstance.cs

@@ -643,21 +643,18 @@ public bool DefinePropertyOrThrow(JsValue property, PropertyDescriptor desc)
         }
 
         /// <summary>
-        /// Creates or alters the named own property to
-        /// have the state described by a Property
-        /// Descriptor. The flag controls failure handling.
+        /// Creates or alters the named own property to have the state described by a PropertyDescriptor.
         /// </summary>
         public virtual bool DefineOwnProperty(JsValue property, PropertyDescriptor desc)
         {
             var current = GetOwnProperty(property);
-            var extensible = Extensible;
 
             if (current == desc)
             {
                 return true;
             }
 
-            return ValidateAndApplyPropertyDescriptor(this, property, extensible, desc, current);
+            return ValidateAndApplyPropertyDescriptor(this, property, Extensible, desc, current);
         }
 
         /// <summary>
@@ -673,7 +670,7 @@ protected static bool ValidateAndApplyPropertyDescriptor(ObjectInstance? o, JsVa
                     return false;
                 }
 
-                if (o is object)
+                if (o is not null)
                 {
                     if (desc.IsGenericDescriptor() || desc.IsDataDescriptor())
                     {
@@ -762,7 +759,7 @@ protected static bool ValidateAndApplyPropertyDescriptor(ObjectInstance? o, JsVa
                         return false;
                     }
 
-                    if (o is object)
+                    if (o is not null)
                     {
                         var flags = current.Flags & ~(PropertyFlag.Writable | PropertyFlag.WritableSet | PropertyFlag.CustomJsValue);
                         if (current.IsDataDescriptor())
@@ -814,7 +811,7 @@ protected static bool ValidateAndApplyPropertyDescriptor(ObjectInstance? o, JsVa
                 }
             }
 
-            if (o is object)
+            if (o is not null)
             {
                 if (!ReferenceEquals(descValue, null))
                 {

Jint/Runtime/Completion.cs

@@ -22,7 +22,7 @@ public enum CompletionType : byte
     [StructLayout(LayoutKind.Auto)]
     public readonly struct Completion
     {
-        internal static readonly Node _emptyNode = new Identifier("");
+        private static readonly Node _emptyNode = new Identifier("");
         private static readonly Completion _emptyCompletion = new(CompletionType.Normal, null!, _emptyNode);
 
         internal readonly SyntaxElement _source;
@@ -36,13 +36,19 @@ internal Completion(CompletionType type, JsValue value, string? target, SyntaxEl
         }
 
         public Completion(CompletionType type, JsValue value, SyntaxElement source)
-            : this(type, value, null, source)
         {
+            Type = type;
+            Value = value;
+            Target = null;
+            _source = source;
         }
 
         public Completion(CompletionType type, string target, SyntaxElement source)
-            : this(type, null!, target, source)
         {
+            Type = type;
+            Value = null!;
+            Target = target;
+            _source = source;
         }
 
         internal Completion(in ExpressionResult result)
@@ -59,9 +65,6 @@ internal Completion(in ExpressionResult result)
         public readonly string? Target;
         public ref readonly Location Location => ref _source.Location;
 
-        public static Completion Normal(JsValue value, Node source)
-            => new Completion(CompletionType.Normal, value, source);
-
         public static ref readonly Completion Empty() => ref _emptyCompletion;
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]

Jint/Runtime/Debugger/DebugScopes.cs

@@ -5,8 +5,8 @@ namespace Jint.Runtime.Debugger
 {
     public sealed class DebugScopes : IReadOnlyList<DebugScope>
     {
-        private readonly HashSet<string> _foundBindings = new HashSet<string>();
-        private readonly List<DebugScope> _scopes = new List<DebugScope>();
+        private readonly HashSet<string> _foundBindings = new();
+        private readonly List<DebugScope> _scopes = new();
 
         internal DebugScopes(EnvironmentRecord environment)
         {
@@ -44,7 +44,7 @@ private void Populate(EnvironmentRecord? environment)
                     case GlobalEnvironmentRecord global:
                         // Similarly to Chromium, we split the Global environment into Global and Script scopes
                         AddScope(DebugScopeType.Script, global._declarativeRecord);
-                        AddScope(DebugScopeType.Global, global._objectRecord);
+                        AddScope(DebugScopeType.Global, new ObjectEnvironmentRecord(environment._engine, global._global, false, false));
                         break;
                     case FunctionEnvironmentRecord:
                         AddScope(inLocalScope ? DebugScopeType.Local : DebugScopeType.Closure, record);