1 files changed, 23 insertions, 0 deletions
diff --git a/src/mscorlib/src/System/Runtime/CompilerServices/CompilerMarshalOverride.cs b/src/mscorlib/src/System/Runtime/CompilerServices/CompilerMarshalOverride.cs
new file mode 100644
index 0000000000..a7b4aca480
--- /dev/null
+++ b/src/mscorlib/src/System/Runtime/CompilerServices/CompilerMarshalOverride.cs
@@ -0,0 +1,23 @@
+// 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.
+
+namespace System.Runtime.CompilerServices
+{
+    // The CLR data marshaler has some behaviors that are incompatible with
+    // C++. Specifically, C++ treats boolean variables as byte size, whereas 
+    // the marshaller treats them as 4-byte size.  Similarly, C++ treats
+    // wchar_t variables as 4-byte size, whereas the marshaller treats them
+    // as single byte size under certain conditions.  In order to work around
+    // such issues, the C++ compiler will emit a type that the marshaller will
+    // marshal using the correct sizes.  In addition, the compiler will place
+    // this modopt onto the variables to indicate that the specified type is
+    // not the true type.  Any compiler that needed to deal with similar
+    // marshalling incompatibilities could use this attribute as well.
+    //
+    // Indicates that the modified instance differs from its true type for
+    // correct marshalling.
+    public static class CompilerMarshalOverride
+    {
+    }
+}