[release/10.0] Look up the correct MethodTable on COM methods. (#121512)

Backport of #121431 to release/10.0

/cc @AaronRobinsonMSFT

## Customer Impact

- [x] Customer reported
- [ ] Found internally

How a COM server is activated can obscure how we determine the `IID` of
a COM interface method. This matters in scenarios involving
`ISupportErrorInfo`. A user reported this in
#121252.

## Regression

- [x] Yes
- [ ] No

This is a regression from .NET 9. It was introduced in
#117690.

## Testing

Tests were updated to validate this behavior.

## Risk

Low. This only impacts COM scenarios involving `ISupportErrorInfo`.

---------

Co-authored-by: Aaron R Robinson <arobins@microsoft.com>

Author: github-actions[bot]

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

@@ -1357,14 +1357,18 @@ internal static Exception GetHRExceptionObject(int hr)
         }
 
 #if FEATURE_COMINTEROP
-        internal static Exception GetCOMHRExceptionObject(int hr, IntPtr pCPCMD, IntPtr pUnk)
+        internal static unsafe Exception GetCOMHRExceptionObject(int hr, IntPtr pCPCMD, IntPtr pUnk)
         {
-            RuntimeMethodHandle handle = RuntimeMethodHandle.FromIntPtr(pCPCMD);
-            RuntimeType declaringType = RuntimeMethodHandle.GetDeclaringType(handle.GetMethodInfo());
+            Debug.Assert(pCPCMD != IntPtr.Zero);
+            MethodTable* interfaceType = GetComInterfaceFromMethodDesc(pCPCMD);
+            RuntimeType declaringType = RuntimeTypeHandle.GetRuntimeType(interfaceType);
             Exception ex = Marshal.GetExceptionForHR(hr, declaringType.GUID, pUnk)!;
             ex.InternalPreserveStackTrace();
             return ex;
         }
+
+        [MethodImpl(MethodImplOptions.InternalCall)]
+        private static extern unsafe MethodTable* GetComInterfaceFromMethodDesc(IntPtr pCPCMD);
 #endif // FEATURE_COMINTEROP
 
         [ThreadStatic]

src/coreclr/vm/ecalllist.h

@@ -352,6 +352,7 @@ FCFuncStart(gStubHelperFuncs)
     FCFuncElement("SetLastError", StubHelpers::SetLastError)
     FCFuncElement("ClearLastError", StubHelpers::ClearLastError)
 #ifdef FEATURE_COMINTEROP
+    FCFuncElement("GetComInterfaceFromMethodDesc", StubHelpers::GetComInterfaceFromMethodDesc)
     FCFuncElement("GetCOMIPFromRCW", StubHelpers::GetCOMIPFromRCW)
 #endif // FEATURE_COMINTEROP
     FCFuncElement("CalcVaListSize", StubHelpers::CalcVaListSize)

src/coreclr/vm/stubhelpers.cpp

@@ -266,6 +266,14 @@ FORCEINLINE static IUnknown* GetCOMIPFromRCW_GetTargetFromRCWCache(SOleTlsData*
     return NULL;
 }
 
+FCIMPL1(MethodTable*, StubHelpers::GetComInterfaceFromMethodDesc, MethodDesc* pMD)
+{
+    FCALL_CONTRACT;
+    _ASSERTE(pMD != NULL);
+    return CLRToCOMCallInfo::FromMethodDesc(pMD)->m_pInterfaceMT;
+}
+FCIMPLEND
+
 //==================================================================================================================
 // The GetCOMIPFromRCW helper exists in four specialized versions to optimize CLR->COM perf. Please be careful when
 // changing this code as one of these methods is executed as part of every CLR->COM call so every instruction counts.

src/coreclr/vm/stubhelpers.h

@@ -26,6 +26,7 @@ class StubHelpers
     //-------------------------------------------------------
 
 #ifdef FEATURE_COMINTEROP
+    static FCDECL1(MethodTable*,    GetComInterfaceFromMethodDesc, MethodDesc* pMD);
     static FCDECL3(IUnknown*,       GetCOMIPFromRCW,    Object* pSrcUNSAFE, MethodDesc* pMD, void **ppTarget);
 #endif // FEATURE_COMINTEROP
 

src/tests/Interop/COM/NETClients/ComDisabled/Program.cs

@@ -22,7 +22,7 @@ public static int TestEntryPoint()
 
             try
             {
-                var server = (Server.Contract.Servers.NumericTesting)new Server.Contract.Servers.NumericTestingClass();
+                var server = new Server.Contract.Servers.NumericTesting();
             }
             catch (NotSupportedException) when (OperatingSystem.IsWindows())
             {

src/tests/Interop/COM/NETClients/Events/Program.cs

@@ -20,7 +20,7 @@ static void Validate_BasicCOMEvent()
         {
             Console.WriteLine($"{nameof(Validate_BasicCOMEvent)}...");
 
-            var eventTesting = (EventTesting)new EventTestingClass();
+            var eventTesting = new EventTesting();
 
             // Verify event handler subscription
 
@@ -57,7 +57,7 @@ static void Validate_COMEventViaComAwareEventInfo()
         {
             Console.WriteLine($"{nameof(Validate_COMEventViaComAwareEventInfo)}...");
 
-            var eventTesting = (EventTesting)new EventTestingClass();
+            var eventTesting = new EventTesting();
 
             // Verify event handler subscription
 

src/tests/Interop/COM/NETClients/IDispatch/Program.cs

@@ -19,7 +19,7 @@ public class Program
     {
         static void Validate_Numeric_In_ReturnByRef()
         {
-            var dispatchTesting = (DispatchTesting)new DispatchTestingClass();
+            var dispatchTesting = new DispatchTesting();
 
             byte b1 = 1;
             byte b2 = b1;
@@ -74,7 +74,7 @@ static private bool EqualByBound(double expected, double actual)
 
         static void Validate_Float_In_ReturnAndUpdateByRef()
         {
-            var dispatchTesting = (DispatchTesting)new DispatchTestingClass();
+            var dispatchTesting = new DispatchTesting();
 
             float a = .1f;
             float b = .2f;
@@ -91,7 +91,7 @@ static void Validate_Float_In_ReturnAndUpdateByRef()
 
         static void Validate_Double_In_ReturnAndUpdateByRef()
         {
-            var dispatchTesting = (DispatchTesting)new DispatchTestingClass();
+            var dispatchTesting = new DispatchTesting();
 
             double a = .1;
             double b = .2;
@@ -114,7 +114,7 @@ static int GetErrorCodeFromHResult(int hresult)
 
         static void Validate_Exception()
         {
-            var dispatchTesting = (DispatchTesting)new DispatchTestingClass();
+            var dispatchTesting = new DispatchTesting();
 
             int errorCode = 1127;
             string resultString = errorCode.ToString("x");
@@ -174,15 +174,15 @@ static void Validate_Exception()
         static void Validate_StructNotSupported()
         {
             Console.WriteLine($"IDispatch with structs not supported...");
-            var dispatchTesting = (DispatchTesting)new DispatchTestingClass();
+            var dispatchTesting = new DispatchTesting();
 
             var input = new HFA_4() { x = 1f, y = 2f, z = 3f, w = 4f };
             Assert.Throws<NotSupportedException>(() => dispatchTesting.DoubleHVAValues(ref input));
         }
 
         static void Validate_LCID_Marshaled()
         {
-            var dispatchTesting = (DispatchTesting)new DispatchTestingClass();
+            var dispatchTesting = new DispatchTesting();
             CultureInfo oldCulture = CultureInfo.CurrentCulture;
             CultureInfo newCulture = new CultureInfo("es-ES", false);
             try
@@ -200,7 +200,7 @@ static void Validate_LCID_Marshaled()
 
         static void Validate_Enumerator()
         {
-            var dispatchTesting = (DispatchTesting)new DispatchTestingClass();
+            var dispatchTesting = new DispatchTesting();
             var expected = System.Linq.Enumerable.Range(0, 10);
 
             {
@@ -251,7 +251,7 @@ static System.Collections.Generic.IEnumerable<int> ConvertEnumerable(System.Coll
 
         static void Validate_ValueCoerce_ReturnToManaged()
         {
-            var dispatchCoerceTesting = (DispatchCoerceTesting)new DispatchCoerceTestingClass();
+            var dispatchCoerceTesting = new DispatchCoerceTesting();
 
             Console.WriteLine($"Calling {nameof(DispatchCoerceTesting.ReturnToManaged)} ...");
 

src/tests/Interop/COM/NETClients/IInspectable/Program.cs

@@ -18,7 +18,7 @@ public class Program
     {
         static void Validate_IInspectable()
         {
-            var server = (InspectableTesting)new InspectableTestingClass();
+            var server = new InspectableTesting();
             Assert.Throws<PlatformNotSupportedException>(() => _ = (IInspectableTesting2)server);
         }
 

src/tests/Interop/COM/NETClients/Licensing/Program.cs

@@ -23,13 +23,13 @@ static void ActivateLicensedObject()
             Console.WriteLine($"Calling {nameof(ActivateLicensedObject)}...");
 
             // Validate activation
-            var licenseTesting = (LicenseTesting)new LicenseTestingClass();
+            var licenseTesting = new LicenseTesting();
 
             // Validate license denial
             licenseTesting.SetNextDenyLicense(true);
             try
             {
-                var tmp = (LicenseTesting)new LicenseTestingClass();
+                var tmp = new LicenseTesting();
                 Assert.Fail("Activation of licensed class should fail");
             }
             catch (COMException e)
@@ -86,7 +86,7 @@ static void ActivateUnderDesigntimeContext()
                 LicenseManager.CurrentContext = new MockLicenseContext(typeof(LicenseTestingClass), LicenseUsageMode.Designtime);
                 LicenseManager.CurrentContext.SetSavedLicenseKey(typeof(LicenseTestingClass), licKey);
 
-                var licenseTesting = (LicenseTesting)new LicenseTestingClass();
+                var licenseTesting = new LicenseTesting();
 
                 // During design time the IClassFactory::CreateInstance will be called - no license
                 Assert.Null(licenseTesting.GetLicense());
@@ -111,7 +111,7 @@ static void ActivateUnderRuntimeContext()
                 LicenseManager.CurrentContext = new MockLicenseContext(typeof(LicenseTestingClass), LicenseUsageMode.Runtime);
                 LicenseManager.CurrentContext.SetSavedLicenseKey(typeof(LicenseTestingClass), licKey);
 
-                var licenseTesting = (LicenseTesting)new LicenseTestingClass();
+                var licenseTesting = new LicenseTesting();
 
                 // During runtime the IClassFactory::CreateInstance2 will be called with license from context
                 Assert.Equal(licKey, licenseTesting.GetLicense());

src/tests/Interop/COM/NETClients/MiscTypes/Program.cs

@@ -87,7 +87,7 @@ private static void ValidationTests()
         {
             Console.WriteLine($"Running {nameof(ValidationTests)} ...");
 
-            var miscTypeTesting = (Server.Contract.Servers.MiscTypesTesting)new Server.Contract.Servers.MiscTypesTestingClass();
+            var miscTypeTesting = new Server.Contract.Servers.MiscTypesTesting();
 
             Console.WriteLine("-- Primitives <=> VARIANT...");
             {
@@ -226,7 +226,7 @@ private static void ValidateNegativeTests()
         {
             Console.WriteLine($"Running {nameof(ValidateNegativeTests)} ...");
 
-            var miscTypeTesting = (Server.Contract.Servers.MiscTypesTesting)new Server.Contract.Servers.MiscTypesTestingClass();
+            var miscTypeTesting = new Server.Contract.Servers.MiscTypesTesting();
 
             Console.WriteLine("-- DispatchWrapper with non-IDispatch object <=> VARIANT...");
             {