For perf, avoid calling ReboxFromNullable when not necessary part 2

dotnet · May 6, 2022 · c7bee67 · c7bee67
1 parent 55a4f95
commit c7bee67
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Showing 3 changed files with 14 additions and 4 deletions.
diff --git a/src/coreclr/System.Private.CoreLib/src/System/RuntimeType.CoreCLR.cs b/src/coreclr/System.Private.CoreLib/src/System/RuntimeType.CoreCLR.cs
@@ -3555,7 +3555,17 @@ internal bool CheckValue(
                     value = binder.ChangeType(value, this, culture);
                     if (IsInstanceOfType(value))
                     {
-                        copyBack = ParameterCopyBackAction.Copy;
+                        if (IsNullableOfT)
+                        {
+                            // Pass as a true boxed Nullable<T>, not as a T or null.
+                            value = RuntimeMethodHandle.ReboxToNullable(value, this);
+                            copyBack = ParameterCopyBackAction.CopyNullable;
+                        }
+                        else
+                        {
+                            copyBack = ParameterCopyBackAction.Copy;
+                        }
+
                         return IsValueType; // Note the call to IsValueType, not the variable.
                     }
 

diff --git a/src/mono/System.Private.CoreLib/src/System/Reflection/RuntimeFieldInfo.cs b/src/mono/System.Private.CoreLib/src/System/Reflection/RuntimeFieldInfo.cs
@@ -278,7 +278,7 @@ public override void SetValue(object? obj, object? val, BindingFlags invokeAttr,
             if (val != null)
             {
                 RuntimeType fieldType = (RuntimeType)FieldType;
-                bool _ = false;
+                ParameterCopyBackAction _ = default;
 
                 if (!ReferenceEquals(val.GetType(), fieldType))
                 {

diff --git a/src/mono/System.Private.CoreLib/src/System/RuntimeType.Mono.cs b/src/mono/System.Private.CoreLib/src/System/RuntimeType.Mono.cs
@@ -1648,15 +1648,15 @@ internal override FieldInfo GetField(FieldInfo fromNoninstanciated)
         /// <returns>Not yet implemented in Mono: True if the value should be considered a value type, False otherwise</returns>
         internal bool CheckValue(
             ref object? value,
-            ref bool copyBack,
+            ref ParameterCopyBackAction copyBack,
             Binder? binder,
             CultureInfo? culture,
             BindingFlags invokeAttr)
         {
             // Already fast-pathed by the caller.
             Debug.Assert(!ReferenceEquals(value?.GetType(), this));
 
-            copyBack = true;
+            copyBack = ParameterCopyBackAction.Copy;
 
             CheckValueStatus status = TryConvertToType(ref value);
             if (status == CheckValueStatus.Success)