Performance improvements (dotnet#938)

* [Perf] Use Runtime.IntPtrEqualityComparer everywhere

This avoid boxing the key for Dictionaries which take IntPtr as keys.

* [Perf] Avoid Tuple allocations and boxing of tuple items

The default implementation of Tuple IEquatable uses EqualityComparer<Object>.Default, which causes boxing for IntPtr.
Implement a hand-made IntPtr-Type tuple that also uses custom comparers defined Runtime, for IntPtr and Type equality.

This should improve allocations done by GetDelegateForBlock

Author: Therzok

src/AudioToolbox/MusicSequence.cs

@@ -45,7 +45,7 @@ internal MusicSequence (IntPtr handle) {
 			this.handle = handle;
 		}
 
-		static Dictionary <IntPtr, MusicSequenceUserCallback> userCallbackHandles = new Dictionary <IntPtr, MusicSequenceUserCallback> ();
+		static Dictionary <IntPtr, MusicSequenceUserCallback> userCallbackHandles = new Dictionary <IntPtr, MusicSequenceUserCallback> (Runtime.IntPtrEqualityComparer);
 
 		static MusicSequenceUserCallbackProxy userCallbackProxy = new MusicSequenceUserCallbackProxy (UserCallbackProxy);
 

src/CoreFoundation/CFMessagePort.cs

@@ -55,11 +55,11 @@ struct ContextProxy {
 
 		delegate void CFMessagePortInvalidationCallBackProxy (/* CFMessagePortRef */ IntPtr messagePort, /* void * */ IntPtr info);
 
-		static Dictionary <IntPtr, CFMessagePortCallBack> outputHandles = new Dictionary <IntPtr, CFMessagePortCallBack> ();
+		static Dictionary <IntPtr, CFMessagePortCallBack> outputHandles = new Dictionary <IntPtr, CFMessagePortCallBack> (Runtime.IntPtrEqualityComparer);
 
-		static Dictionary <IntPtr, Action> invalidationHandles = new Dictionary <IntPtr, Action> ();
+		static Dictionary <IntPtr, Action> invalidationHandles = new Dictionary <IntPtr, Action> (Runtime.IntPtrEqualityComparer);
 
-		static Dictionary <IntPtr, CFMessagePortContext> messagePortContexts = new Dictionary <IntPtr, CFMessagePortContext> ();
+		static Dictionary <IntPtr, CFMessagePortContext> messagePortContexts = new Dictionary <IntPtr, CFMessagePortContext> (Runtime.IntPtrEqualityComparer);
 
 		static CFMessagePortCallBackProxy messageOutputCallback = new CFMessagePortCallBackProxy (MessagePortCallback);
 

src/CoreMedia/CMBufferQueue.cs

@@ -113,7 +113,7 @@ protected virtual void Dispose (bool disposing)
 
 		internal CMBufferQueue (int count)
 		{
-			queueObjects = new Dictionary<IntPtr,INativeObject> (count);
+			queueObjects = new Dictionary<IntPtr,INativeObject> (count, Runtime.IntPtrEqualityComparer);
 			gch = GCHandle.Alloc (this);
 		}
 

src/ObjCRuntime/DynamicRegistrar.cs

@@ -119,7 +119,7 @@ public Dictionary<IntPtr, MethodDescription> GetMethods (Type type)
 				RegisterType (type);
 
 				if (!method_map.TryGetValue (type, out methods)) {
-					methods = new Dictionary <IntPtr, MethodDescription> ();
+					methods = new Dictionary <IntPtr, MethodDescription> (Runtime.IntPtrEqualityComparer);
 					method_map [type] = methods;
 				}
 
@@ -804,7 +804,7 @@ monotouch.dll since we don't link all frameworks most of the time. */
 			if (type.IsFakeProtocol)
 				return;
 
-			var methods = new Dictionary <IntPtr, MethodDescription> ();
+			var methods = new Dictionary <IntPtr, MethodDescription> (Runtime.IntPtrEqualityComparer);
 
 			var super = type.SuperType;
 

src/ObjCRuntime/Runtime.cs

@@ -36,7 +36,7 @@ public partial class Runtime {
 		internal const bool IsUnifiedBuild = false;
 #endif
 
-		static Dictionary<Tuple<IntPtr,Type>,Delegate> block_to_delegate_cache;
+		static Dictionary<IntPtrTypeValueTuple,Delegate> block_to_delegate_cache;
 
 		static List <object> delegates;
 		static List <Assembly> assemblies;
@@ -753,13 +753,13 @@ static Delegate CreateBlockProxy (MethodInfo method, IntPtr block)
 		static Delegate GetDelegateForBlock (IntPtr methodPtr, Type type)
 		{
 			if (block_to_delegate_cache == null)
-				block_to_delegate_cache = new Dictionary<Tuple<IntPtr, Type>, Delegate> ();
+				block_to_delegate_cache = new Dictionary<IntPtrTypeValueTuple, Delegate> ();
 
 			// We do not care if there is a race condition and we initialize two caches
 			// since the worst that can happen is that we end up with an extra
 			// delegate->function pointer.
 			Delegate val;
-			var pair = new Tuple<IntPtr, Type> (methodPtr, type);
+			var pair = new IntPtrTypeValueTuple (methodPtr, type);
 			lock (block_to_delegate_cache) {
 				if (block_to_delegate_cache.TryGetValue (pair, out val))
 					return val;
@@ -1356,4 +1356,48 @@ public int GetHashCode (Type obj)
 			return obj.GetHashCode ();
 		}
 	}
+
+	internal struct IntPtrTypeValueTuple : IEquatable<IntPtrTypeValueTuple>
+	{
+		static readonly IEqualityComparer<IntPtr> item1Comparer = Runtime.IntPtrEqualityComparer;
+		static readonly IEqualityComparer<Type> item2Comparer = Runtime.TypeEqualityComparer;
+
+		public readonly IntPtr Item1;
+		public readonly Type Item2;
+
+		public IntPtrTypeValueTuple (IntPtr item1, Type item2)
+		{
+			Item1 = item1;
+			Item2 = item2;
+		}
+
+		public bool Equals (IntPtrTypeValueTuple other)
+		{
+			return item1Comparer.Equals (Item1, other.Item1) &&
+				item2Comparer.Equals (Item2, other.Item2);
+		}
+
+		public override bool Equals (object obj)
+		{
+			if (obj is IntPtrTypeValueTuple)
+				return Equals ((IntPtrTypeValueTuple)obj);
+
+			return false;
+		}
+
+		public override int GetHashCode ()
+		{
+			return item1Comparer.GetHashCode (Item1) ^ item2Comparer.GetHashCode (Item2);
+		}
+
+		public static bool operator == (IntPtrTypeValueTuple left, IntPtrTypeValueTuple right)
+		{
+			return left.Equals(right);
+		}
+
+		public static bool operator != (IntPtrTypeValueTuple left, IntPtrTypeValueTuple right)
+		{
+			return !left.Equals(right);
+		}
+	}
 }