Explicitly handle char marshalling in OleVariant::GetNativeMethodTableForVarType.

src/vm/olevariant.cpp

@@ -803,50 +803,54 @@ MethodTable* OleVariant::GetNativeMethodTableForVarType(VARTYPE vt, MethodTable*
 {
     CONTRACTL
     {
-        NOTHROW;
-        GC_NOTRIGGER;
+        THROWS;
+        GC_TRIGGERS;
         MODE_ANY;
     }
     CONTRACTL_END;
 
+    if (vt & VT_ARRAY)
     {
-        GCX_COOP();
-        if (vt & VT_ARRAY)
-        {
-            return MscorlibBinder::GetClass(CLASS__INTPTR);
-        }
+        return MscorlibBinder::GetClass(CLASS__INTPTR);
+    }
 
-        switch (vt)
-        {
-            case VT_DATE:
-                return MscorlibBinder::GetClass(CLASS__DOUBLE);
-            case VT_CY:
-                return MscorlibBinder::GetClass(CLASS__CURRENCY);
-            case VTHACK_WINBOOL:
-                return MscorlibBinder::GetClass(CLASS__INT32);
-            case VT_BOOL:
-                return MscorlibBinder::GetClass(CLASS__INT16);
-            case VTHACK_CBOOL:
-                return MscorlibBinder::GetClass(CLASS__BYTE);
-            case VT_DISPATCH:
-            case VT_UNKNOWN:
-            case VT_LPSTR:
-            case VT_LPWSTR:
-            case VT_BSTR:
-            case VT_USERDEFINED:
-            case VT_SAFEARRAY:
-            case VT_CARRAY:
-                return MscorlibBinder::GetClass(CLASS__INTPTR);
-            case VT_VARIANT:
-                return MscorlibBinder::GetClass(CLASS__NATIVEVARIANT);
-            default:
-                PREFIX_ASSUME(pManagedMT != NULL);
-                return pManagedMT;
-        }
+    switch (vt)
+    {
+        case VT_DATE:
+            return MscorlibBinder::GetClass(CLASS__DOUBLE);
+        case VT_CY:
+            return MscorlibBinder::GetClass(CLASS__CURRENCY);
+        case VTHACK_WINBOOL:
+            return MscorlibBinder::GetClass(CLASS__INT32);
+        case VT_BOOL:
+            return MscorlibBinder::GetClass(CLASS__INT16);
+        case VTHACK_CBOOL:
+            return MscorlibBinder::GetClass(CLASS__BYTE);
+        case VT_DISPATCH:
+        case VT_UNKNOWN:
+        case VT_LPSTR:
+        case VT_LPWSTR:
+        case VT_BSTR:
+        case VT_USERDEFINED:
+        case VT_SAFEARRAY:
+        case VT_CARRAY:
+            return MscorlibBinder::GetClass(CLASS__INTPTR);
+        case VT_VARIANT:
+            return MscorlibBinder::GetClass(CLASS__NATIVEVARIANT);
+        case VTHACK_ANSICHAR:
+            return MscorlibBinder::GetClass(CLASS__BYTE);
+        case VT_UI2:
+            // When CharSet = CharSet.Unicode, System.Char arrays are marshaled as VT_UI2.
+            // However, since System.Char itself is CharSet.Ansi, the native size of
+            // System.Char is 1 byte instead of 2. So here we explicitly return System.UInt16's
+            // MethodTable to ensure the correct size.
+            return MscorlibBinder::GetClass(CLASS__UINT16);
+        default:
+            PREFIX_ASSUME(pManagedMT != NULL);
+            return pManagedMT;
     }
 }
 
-
 //
 // GetMarshalerForVarType returns the marshaler for the
 // given VARTYPE.

tests/src/Interop/StructMarshalling/PInvoke/MarshalStructAsLayoutSeq.cs

@@ -29,6 +29,7 @@ enum StructID
         SequentialDoubleWrapperId,
         AggregateSequentialWrapperId,
         FixedBufferClassificationTestId,
+        UnicodeCharArrayClassificationId,
         HFAId,
         DoubleHFAId
     }
@@ -327,6 +328,8 @@ public static int Main()
     [DllImport("MarshalStructAsParam")]
     static extern bool MarshalStructAsParam_AsSeqByValFixedBufferClassificationTest(FixedArrayClassificationTest str, float f);
     [DllImport("MarshalStructAsParam")]
+    static extern bool MarshalStructAsParam_AsSeqByValUnicodeCharArrayClassification(UnicodeCharArrayClassification str, float f);
+    [DllImport("MarshalStructAsParam")]
     static extern int GetStringLength(AutoString str);
 
     [DllImport("MarshalStructAsParam")]
@@ -680,6 +683,19 @@ unsafe private static void MarshalStructAsParam_AsSeqByVal(StructID id)
                         failures++;
                     }
                     break;
+                case StructID.UnicodeCharArrayClassificationId:
+                    Console.WriteLine("\tCalling MarshalStructAsParam_AsSeqByValUnicodeCharArrayClassification with nonblittable struct...");
+                    unsafe
+                    {
+                        UnicodeCharArrayClassification str = new UnicodeCharArrayClassification { arr = new char[6] };
+                        str.f = 56.789f;
+                        if (!MarshalStructAsParam_AsSeqByValUnicodeCharArrayClassification(str, str.f))
+                        {
+                            Console.WriteLine("\tFAILED! Managed to Native failed in MarshalStructAsParam_AsSeqByValUnicodeCharArrayClassification. Expected:True;Actual:False");
+                            failures++;
+                        }
+                    }
+                    break;
                 case StructID.HFAId:
                 {
                     HFA hfa = new HFA
@@ -2345,6 +2361,7 @@ private static void RunMarshalSeqStructAsParamByVal()
         MarshalStructAsParam_AsSeqByVal(StructID.SequentialDoubleWrapperId);
         MarshalStructAsParam_AsSeqByVal(StructID.AggregateSequentialWrapperId);
         MarshalStructAsParam_AsSeqByVal(StructID.FixedBufferClassificationTestId);
+        MarshalStructAsParam_AsSeqByVal(StructID.UnicodeCharArrayClassificationId);
         MarshalStructAsParam_AsSeqByVal(StructID.HFAId);
         MarshalStructAsParam_AsSeqByVal(StructID.DoubleHFAId);
     }

tests/src/Interop/StructMarshalling/PInvoke/MarshalStructAsParamDLL.cpp

@@ -1194,6 +1194,11 @@ extern "C" DLL_EXPORT BOOL STDMETHODCALLTYPE MarshalStructAsParam_AsSeqByValFixe
     return str.f == f;
 }
 
+extern "C" DLL_EXPORT BOOL STDMETHODCALLTYPE MarshalStructAsParam_AsSeqByValUnicodeCharArrayClassification(UnicodeCharArrayClassification str, float f)
+{
+    return str.f == f;
+}
+
 ////////////////////////////////////////////////////////////////////////////////////
 extern "C" DLL_EXPORT int GetStringLength(AutoString str)
 {

tests/src/Interop/StructMarshalling/PInvoke/MarshalStructAsParamDLL.h

@@ -957,3 +957,9 @@ union OverlappingMultipleEightbyteMultiple
         int i[3];
     };
 };
+
+struct UnicodeCharArrayClassification
+{
+    WCHAR arr[6];
+    float f;
+};

tests/src/Interop/StructMarshalling/PInvoke/Struct.cs

@@ -485,3 +485,11 @@ public unsafe struct FixedArrayClassificationTest
     public Int32Wrapper[] arr;
     public float f;
 }
+
+[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
+public struct UnicodeCharArrayClassification
+{
+    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 6)]
+    public char[] arr;
+    public float f;
+}