From 44b70d87e5980ffd0c3c8c9558e9f26ecdf6dd13 Mon Sep 17 00:00:00 2001
From: Ari Vuollet <ari.vuollet@kapsi.fi>
Date: Fri, 4 Aug 2023 21:38:05 +0300
Subject: [PATCH] Cache MakeArrayType results in native interop

---
 Source/Engine/Engine/NativeInterop.Managed.cs | 21 ++++++++++---------
 .../Engine/Engine/NativeInterop.Unmanaged.cs  |  4 ++--
 Source/Engine/Engine/NativeInterop.cs         | 10 +++++++++
 3 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/Source/Engine/Engine/NativeInterop.Managed.cs b/Source/Engine/Engine/NativeInterop.Managed.cs
index 95146a95c..86b41f458 100644
--- a/Source/Engine/Engine/NativeInterop.Managed.cs
+++ b/Source/Engine/Engine/NativeInterop.Managed.cs
@@ -91,18 +91,19 @@ namespace FlaxEngine.Interop
 
         internal void Allocate<T>(int length) where T : unmanaged
         {
+            _length = length;
+            _arrayType = typeof(T[]);
+            _elementType = typeof(T);
+            _elementSize = Unsafe.SizeOf<T>();
+
             // Try to reuse existing allocated buffer
-            if (length * Unsafe.SizeOf<T>() > _unmanagedAllocationSize)
+            if (length * _elementSize > _unmanagedAllocationSize)
             {
                 if (_unmanagedAllocationSize > 0)
                     NativeInterop.NativeFree(_unmanagedData.ToPointer());
-                _unmanagedData = (IntPtr)NativeInterop.NativeAlloc(length, Unsafe.SizeOf<T>());
-                _unmanagedAllocationSize = Unsafe.SizeOf<T>() * length;
+                _unmanagedData = (IntPtr)NativeInterop.NativeAlloc(length, _elementSize);
+                _unmanagedAllocationSize = _elementSize * length;
             }
-            _length = length;
-            _arrayType = typeof(T).MakeArrayType();
-            _elementType = typeof(T);
-            _elementSize = Unsafe.SizeOf<T>();
         }
 
         private ManagedArray()
@@ -112,12 +113,12 @@ namespace FlaxEngine.Interop
         private ManagedArray(IntPtr ptr, int length, Type arrayType, Type elementType)
         {
             Assert.IsTrue(arrayType.IsArray);
+            _elementType = elementType;
+            _elementSize = NativeInterop.GetTypeSize(elementType);
             _unmanagedData = ptr;
-            _unmanagedAllocationSize = Marshal.SizeOf(elementType) * length;
+            _unmanagedAllocationSize = _elementSize * length;
             _length = length;
             _arrayType = arrayType;
-            _elementType = elementType;
-            _elementSize = NativeInterop.GetTypeSize(_elementType);
         }
 
         ~ManagedArray()
diff --git a/Source/Engine/Engine/NativeInterop.Unmanaged.cs b/Source/Engine/Engine/NativeInterop.Unmanaged.cs
index d2a8ca55e..86fe3036e 100644
--- a/Source/Engine/Engine/NativeInterop.Unmanaged.cs
+++ b/Source/Engine/Engine/NativeInterop.Unmanaged.cs
@@ -526,7 +526,7 @@ namespace FlaxEngine.Interop
         {
             Type elementType = Unsafe.As<Type>(typeHandle.Target);
             Type marshalledType = ArrayFactory.GetMarshalledType(elementType);
-            Type arrayType = elementType.MakeArrayType();
+            Type arrayType = ArrayFactory.GetArrayType(elementType);
             if (marshalledType.IsValueType)
             {
                 ManagedArray managedArray = ManagedArray.AllocateNewArray((int)size, arrayType, marshalledType);
@@ -544,7 +544,7 @@ namespace FlaxEngine.Interop
         internal static ManagedHandle GetArrayTypeFromElementType(ManagedHandle elementTypeHandle)
         {
             Type elementType = Unsafe.As<Type>(elementTypeHandle.Target);
-            Type classType = elementType.MakeArrayType();
+            Type classType = ArrayFactory.GetArrayType(elementType);
             return GetTypeGCHandle(classType);
         }
 
diff --git a/Source/Engine/Engine/NativeInterop.cs b/Source/Engine/Engine/NativeInterop.cs
index da372ac90..0949533ce 100644
--- a/Source/Engine/Engine/NativeInterop.cs
+++ b/Source/Engine/Engine/NativeInterop.cs
@@ -967,6 +967,7 @@ namespace FlaxEngine.Interop
             private delegate Array CreateArrayDelegate(long size);
 
             private static ConcurrentDictionary<Type, Type> marshalledTypes = new ConcurrentDictionary<Type, Type>(1, 3);
+            private static ConcurrentDictionary<Type, Type> arrayTypes = new ConcurrentDictionary<Type, Type>(1, 3);
             private static ConcurrentDictionary<Type, CreateArrayDelegate> createArrayDelegates = new ConcurrentDictionary<Type, CreateArrayDelegate>(1, 3);
 
             internal static Type GetMarshalledType(Type elementType)
@@ -986,6 +987,15 @@ namespace FlaxEngine.Interop
                 return marshalledTypes.GetOrAdd(elementType, Factory);
             }
 
+            internal static Type GetArrayType(Type elementType)
+            {
+                static Type Factory(Type type) => type.MakeArrayType();
+
+                if (arrayTypes.TryGetValue(elementType, out var arrayType))
+                    return arrayType;
+                return arrayTypes.GetOrAdd(elementType, Factory);
+            }
+
             internal static Array CreateArray(Type type, long size)
             {
                 static CreateArrayDelegate Factory(Type type)