Add IL Emit support for MethodInfo.Invoke() and friends

src/coreclr/System.Private.CoreLib/src/System/Reflection/Emit/DynamicMethod.cs

@@ -524,7 +524,7 @@ Signature LazyCreateSignature()
                     {
                         if (shouldCopyBackParameters[i])
                         {
-                            parameters[i] = copyOfParameters[i];
+                            parameters[i] = RuntimeMethodHandle.ReboxFromNullable(copyOfParameters[i]);
                         }
                     }
                 }
@@ -584,7 +584,7 @@ Signature LazyCreateSignature()
             {
                 if (shouldCopyBackParameters[i])
                 {
-                    parameters[i] = copyOfParameters[i];
+                    parameters[i] = RuntimeMethodHandle.ReboxFromNullable(copyOfParameters[i]);
                 }
             }
 
@@ -593,23 +593,9 @@ Signature LazyCreateSignature()
 
         [DebuggerHidden]
         [DebuggerStepThrough]
-        internal unsafe object? InvokeNonEmitUnsafe(object? obj, IntPtr* arguments, BindingFlags invokeAttr)
+        internal unsafe object? InvokeNonEmitUnsafe(object? obj, IntPtr* arguments)
         {
-            if ((invokeAttr & BindingFlags.DoNotWrapExceptions) == 0)
-            {
-                try
-                {
-                    return RuntimeMethodHandle.InvokeMethod(obj, (void**)arguments, Signature, isConstructor: false);
-                }
-                catch (Exception e)
-                {
-                    throw new TargetInvocationException(e);
-                }
-            }
-            else
-            {
-                return RuntimeMethodHandle.InvokeMethod(obj, (void**)arguments, Signature, isConstructor: false);
-            }
+            return RuntimeMethodHandle.InvokeMethod(obj, (void**)arguments, Signature, isConstructor: false);
         }
 
         public override object[] GetCustomAttributes(Type attributeType, bool inherit)

src/coreclr/System.Private.CoreLib/src/System/Reflection/Emit/DynamicMethodInvoker.cs

@@ -1,9 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Diagnostics;
-using System.Runtime.CompilerServices;
-
 namespace System.Reflection.Emit
 {
     internal sealed partial class DynamicMethodInvoker
@@ -17,8 +14,23 @@ public DynamicMethodInvoker(DynamicMethod dynamicMethod)
 
         public unsafe object? InvokeUnsafe(object? obj, IntPtr* args, BindingFlags invokeAttr)
         {
-            // Todo: add strategy for calling IL Emit-based version
-            return _dynamicMethod.InvokeNonEmitUnsafe(obj, args, invokeAttr);
+            // Always use the slow path; the Emit-based fast path can be added but in general dynamic
+            // methods are invoked through a direct delegate, not through Invoke().
+            if ((invokeAttr & BindingFlags.DoNotWrapExceptions) == 0)
+            {
+                try
+                {
+                    return _dynamicMethod.InvokeNonEmitUnsafe(obj, args);
+                }
+                catch (Exception e)
+                {
+                    throw new TargetInvocationException(e);
+                }
+            }
+            else
+            {
+                return _dynamicMethod.InvokeNonEmitUnsafe(obj, args);
+            }
         }
     }
 }

src/coreclr/System.Private.CoreLib/src/System/Reflection/RuntimeConstructorInfo.CoreCLR.cs

@@ -95,26 +95,15 @@ Signature LazyCreateSignature()
 
         internal BindingFlags BindingFlags => m_bindingFlags;
 
+#pragma warning disable CA1822 // Mark members as static
+        internal bool SupportsNewInvoke => true;
+#pragma warning restore CA1822 // Mark members as static
 
         [DebuggerStepThrough]
         [DebuggerHidden]
         internal unsafe object InvokeNonEmitUnsafe(object? obj, IntPtr* args, Span<object?> argsForTemporaryMonoSupport, BindingFlags invokeAttr)
         {
-            if ((invokeAttr & BindingFlags.DoNotWrapExceptions) == 0)
-            {
-                try
-                {
-                    return RuntimeMethodHandle.InvokeMethod(obj, (void**)args, Signature, isConstructor: obj is null)!;
-                }
-                catch (Exception ex)
-                {
-                    throw new TargetInvocationException(ex);
-                }
-            }
-            else
-            {
-                return RuntimeMethodHandle.InvokeMethod(obj, (void**)args, Signature, isConstructor: obj is null)!;
-            }
+            return RuntimeMethodHandle.InvokeMethod(obj, (void**)args, Signature, isConstructor: obj is null)!;
         }
         #endregion
 

src/coreclr/System.Private.CoreLib/src/System/Reflection/RuntimeMethodInfo.CoreCLR.cs

@@ -372,25 +372,15 @@ public override MethodImplAttributes GetMethodImplementationFlags()
             return retValue;
         }
 
+#pragma warning disable CA1822 // Mark members as static
+        internal bool SupportsNewInvoke => true;
+#pragma warning restore CA1822 // Mark members as static
+
         [DebuggerHidden]
         [DebuggerStepThrough]
         internal unsafe object? InvokeNonEmitUnsafe(object? obj, IntPtr* arguments, Span<object?> argsForTemporaryMonoSupport, BindingFlags invokeAttr)
         {
-            if ((invokeAttr & BindingFlags.DoNotWrapExceptions) == 0)
-            {
-                try
-                {
-                    return RuntimeMethodHandle.InvokeMethod(obj, (void**)arguments, Signature, isConstructor: false);
-                }
-                catch (Exception e)
-                {
-                    throw new TargetInvocationException(e);
-                }
-            }
-            else
-            {
-                return RuntimeMethodHandle.InvokeMethod(obj, (void**)arguments, Signature, isConstructor: false);
-            }
+            return RuntimeMethodHandle.InvokeMethod(obj, (void**)arguments, Signature, isConstructor: false);
         }
 
         #endregion

src/coreclr/System.Private.CoreLib/src/System/RuntimeHandles.cs

@@ -981,6 +981,12 @@ internal static MdUtf8String GetUtf8Name(RuntimeMethodHandleInternal method)
         [MethodImpl(MethodImplOptions.InternalCall)]
         internal static extern object? InvokeMethod(object? target, void** arguments, Signature sig, bool isConstructor);
 
+        [MethodImpl(MethodImplOptions.InternalCall)]
+        internal static extern object? ReboxFromNullable(object? src);
+
+        [MethodImpl(MethodImplOptions.InternalCall)]
+        internal static extern object ReboxToNullable(object? src, RuntimeType destNullableType);
+
         [LibraryImport(RuntimeHelpers.QCall, EntryPoint = "RuntimeMethodHandle_GetMethodInstantiation")]
         private static partial void GetMethodInstantiation(RuntimeMethodHandleInternal method, ObjectHandleOnStack types, Interop.BOOL fAsRuntimeTypeArray);