1 files changed, 48 insertions, 0 deletions
diff --git a/src/ILCompiler.Compiler/src/Compiler/DynamicInvokeThunkGenerationPolicy.cs b/src/ILCompiler.Compiler/src/Compiler/DynamicInvokeThunkGenerationPolicy.cs
new file mode 100644
index 000000000..e4f3f67d7
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+++ b/src/ILCompiler.Compiler/src/Compiler/DynamicInvokeThunkGenerationPolicy.cs
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+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Internal.TypeSystem;
+
+namespace ILCompiler
+{
+    /// <summary>
+    /// Controls the way calling convention conversion is performed in
+    /// <see cref="System.Reflection.MethodBase.Invoke(object, object[])"/>
+    /// scenarios.
+    /// </summary>
+    public abstract class DynamicInvokeThunkGenerationPolicy
+    {
+        /// <summary>
+        /// Gets a value indicating whether reflection-invokable method '<paramref name="targetMethod"/>'
+        /// should get a static calling convention conversion thunk. Static calling convention
+        /// conversion thunks speed up reflection invoke of the method at the cost of extra code generation.
+        /// </summary>
+        public abstract bool HasStaticInvokeThunk(MethodDesc targetMethod);
+    }
+
+    /// <summary>
+    /// A thunk generation policy that generates no static invocation thunks.
+    /// </summary>
+    public sealed class NoDynamicInvokeThunkGenerationPolicy : DynamicInvokeThunkGenerationPolicy
+    {
+        public override bool HasStaticInvokeThunk(MethodDesc targetMethod) => false;
+    }
+
+    /// <summary>
+    /// A thunk generation policy that uses static invocation thunks whenever possible.
+    /// </summary>
+    public sealed class DefaultDynamicInvokeThunkGenerationPolicy : DynamicInvokeThunkGenerationPolicy
+    {
+        public override bool HasStaticInvokeThunk(MethodDesc targetMethod)
+        {
+            // Place an upper limit on how many parameters a method can have to still get a static stub.
+            // From the past experience, methods taking 8000+ parameters get a stub that can hit various limitations
+            // in the codegen. On Project N, we were limited to 256 parameters because of MDIL limitations.
+            // We don't have such limitations here, but it's a nice round number.
+            // Reflection invoke will still work, but will go through the calling convention converter.
+
+            return targetMethod.Signature.Length <= 256;
+        }
+    }
+}