Resolve dllimport.cpp runtimeasync todos

src/coreclr/dlls/mscorrc/mscorrc.rc

@@ -593,6 +593,7 @@ BEGIN
         BFA_MISSING_DELEGATE_METHOD             "Missing definition for required runtime implemented delegate method."
         BFA_MULT_TYPE_SAME_NAME                 "Duplicate type with name '%1' in assembly '%2'."
         BFA_INVALID_METHOD_TOKEN                "Bad method token."
+        BFA_BAD_ASYNC_METHOD                    "Bad use of RuntimeAsync flag."
         BFA_ECALLS_MUST_BE_IN_SYS_MOD           "ECall methods must be packaged into a system module."
         BFA_CANT_GET_CLASSLAYOUT                "Could not get classlayout."
         BFA_CALLCONV_NOT_LOCAL_SIG              "Signature is not IMAGE_CEE_CS_CALLCONV_LOCAL_SIG."

src/coreclr/dlls/mscorrc/resource.h

@@ -366,6 +366,7 @@
 #define BFA_MISSING_DELEGATE_METHOD             0x2030
 #define BFA_MULT_TYPE_SAME_NAME                 0x2031
 #define BFA_INVALID_METHOD_TOKEN                0x2032
+#define BFA_BAD_ASYNC_METHOD                0x2033
 #define BFA_ECALLS_MUST_BE_IN_SYS_MOD           0x2034
 #define BFA_CANT_GET_CLASSLAYOUT                0x2035
 #define BFA_CALLCONV_NOT_LOCAL_SIG              0x2036

src/coreclr/vm/comdelegate.cpp

@@ -2045,6 +2045,10 @@ void COMDelegate::ThrowIfInvalidUnmanagedCallersOnlyUsage(MethodDesc* pMD)
     if (pMD->HasClassOrMethodInstantiation())
         EX_THROW(EEResourceException, (kInvalidProgramException, W("InvalidProgram_GenericMethod")));
 
+    // No async methods
+    if (pMD->IsAsyncMethod())
+        EX_THROW(EEResourceException, (kInvalidProgramException, W("InvalidProgram_AsyncMethod")));
+
     // Arguments - Scenarios involving UnmanagedCallersOnly are handled during the jit.
     bool unmanagedCallersOnlyRequiresMarshalling = false;
     if (PInvoke::MarshalingRequired(pMD, NULL, NULL, NULL, unmanagedCallersOnlyRequiresMarshalling))

src/coreclr/vm/dllimport.cpp

@@ -100,6 +100,7 @@ StubSigDesc::StubSigDesc(MethodDesc *pMD)
         GC_NOTRIGGER;
         SUPPORTS_DAC;
         PRECONDITION(pMD != NULL);
+        PRECONDITION(!pMD->IsAsyncMethod());
     }
     CONTRACTL_END;
 
@@ -108,9 +109,6 @@ StubSigDesc::StubSigDesc(MethodDesc *pMD)
     m_sig           = pMD->GetSignature();
     m_pModule       = pMD->GetModule();         // Used for token resolution.
 
-    // TODO: (async) revisit and examine if this needs to be supported somehow
-    _ASSERTE(!pMD->IsAsyncMethod());
-
     m_tkMethodDef = pMD->GetMemberDef();
     SigTypeContext::InitTypeContext(pMD, &m_typeContext);
     m_pMetadataModule = pMD->GetModule();
@@ -1131,7 +1129,6 @@ class ILStubState : public StubState
         DWORD dwToken = 0;
         if (pTargetMD)
         {
-            // TODO: (async) revisit and examine if this needs to be supported somehow
             _ASSERTE(!pTargetMD->IsAsyncVariantMethod());
             dwToken = pTargetMD->GetMemberDef();
         }
@@ -2764,6 +2761,10 @@ void PInvokeStaticSigInfo::DllImportInit(
 
         PRECONDITION(CheckPointer(pMD));
 
+        // P/Invoke methods should never be marked as async.
+        // This should be blocked in the class loader.
+        PRECONDITION(!pMD->IsAsyncMethod());
+
         // These preconditions to prevent multithreaded regression
         // where pMD->m_szLibName was passed in directly, cleared
         // by this API, then accessed on another thread before being reset here.
@@ -2779,9 +2780,6 @@ void PInvokeStaticSigInfo::DllImportInit(
     IMDInternalImport  *pInternalImport = pMD->GetMDImport();
     CorPinvokeMap mappingFlags = pmMaxValue;
     mdModuleRef modref = mdModuleRefNil;
-    // TODO: (async) revisit and examine if this needs to be supported somehow
-    if (pMD->IsAsyncMethod())
-        ThrowHR(COR_E_NOTSUPPORTED);
 
     if (FAILED(pInternalImport->GetPinvokeMap(pMD->GetMemberDef(), (DWORD*)&mappingFlags, ppEntryPointName, &modref)))
     {
@@ -3053,16 +3051,15 @@ namespace
             STANDARD_VM_CHECK;
             PRECONDITION(pMD != NULL);
             PRECONDITION(pMD->IsPInvoke());
+            PRECONDITION(!pMD->IsAsyncMethod());
             PRECONDITION(callConv != NULL);
         }
         CONTRACTL_END;
 
         CorInfoCallConvExtension callConvLocal;
         IMDInternalImport* pInternalImport = pMD->GetMDImport();
         CorPinvokeMap mappingFlags = pmMaxValue;
-        // TODO: (async) revisit and examine if this needs to be supported somehow
-        if (pMD->IsAsyncMethod())
-            ThrowHR(COR_E_NOTSUPPORTED);
+
 
         HRESULT hr = pInternalImport->GetPinvokeMap(pMD->GetMemberDef(), (DWORD*)&mappingFlags, NULL /*pszImportName*/, NULL /*pmrImportDLL*/);
         if (FAILED(hr))
@@ -3249,6 +3246,12 @@ BOOL PInvoke::MarshalingRequired(
     {
         STANDARD_VM_CHECK;
         PRECONDITION(pMD != NULL || (!sigPointer.IsNull() && pModule != NULL));
+
+        // We should never see an async method here.
+        // Delegate Invoke methods should never be async.
+        // Async P/Invokes are not supported.
+        // Async UnmanagedCallersOnly methods are not supported.
+        PRECONDITION(pMD == NULL || !pMD->IsAsyncMethod());
     }
     CONTRACTL_END;
 
@@ -3324,10 +3327,6 @@ BOOL PInvoke::MarshalingRequired(
     mdMethodDef methodToken = mdMethodDefNil;
     if (pMD != NULL)
     {
-        // TODO: (async) revisit and examine if this needs to be supported somehow
-        if (pMD->IsAsyncMethod())
-            ThrowHR(COR_E_NOTSUPPORTED);
-
         methodToken = pMD->GetMemberDef();
     }
     CollateParamTokens(pMDImport, methodToken, numArgs - 1, pParamTokenArray);
@@ -6080,12 +6079,10 @@ static void GetILStubForCalli(VASigCookie* pVASigCookie, MethodDesc* pMD)
 
     if (pMD != NULL)
     {
+        _ASSERTE(pMD->IsPInvoke());
+        _ASSERTE(!pMD->IsAsyncMethod());
         PInvokeStaticSigInfo sigInfo(pMD);
 
-        // TODO: (async) revisit and examine if this needs to be supported somehow
-        if (pMD->IsAsyncMethod())
-            ThrowHR(COR_E_NOTSUPPORTED);
-
         md = pMD->GetMemberDef();
         nlFlags = sigInfo.GetLinkFlags();
         nlType  = sigInfo.GetCharSet();

src/coreclr/vm/methodtablebuilder.cpp

@@ -3183,6 +3183,11 @@ MethodTableBuilder::EnumerateClassMethods()
                 CONSISTENCY_CHECK(hr == S_OK);
                 type = mcPInvoke;
             }
+
+            if (IsMiAsync(dwImplFlags))
+            {
+                BuildMethodTableThrowException(BFA_BAD_ASYNC_METHOD);
+            }
         }
         else if (IsMiRuntime(dwImplFlags))
         {
@@ -3227,6 +3232,11 @@ MethodTableBuilder::EnumerateClassMethods()
             }
 
             delegateMethodsSeen |= newDelegateMethodSeen;
+
+            if (IsMiAsync(dwImplFlags))
+            {
+                BuildMethodTableThrowException(BFA_BAD_ASYNC_METHOD);
+            }
         }
         else if (hasGenericMethodArgs)
         {
@@ -3254,6 +3264,12 @@ MethodTableBuilder::EnumerateClassMethods()
                 // pointer-sized field pointing to COM interop data which are
                 // allocated lazily when/if the MD actually gets used for interop.
                 type = mcComInterop;
+
+                // The interface method itself should never be marked as a runtime-async method.
+                if (IsMiAsync(dwImplFlags))
+                {
+                    BuildMethodTableThrowException(BFA_BAD_ASYNC_METHOD);
+                }
             }
             else
 #endif // !FEATURE_COMINTEROP
@@ -3432,15 +3448,13 @@ MethodTableBuilder::EnumerateClassMethods()
                 }
 
                 MethodClassification asyncVariantType = type;
-#ifdef FEATURE_COMINTEROP
-                if (type == mcComInterop)
+                if (type != mcIL && type != mcInstantiated)
                 {
-                    // For COM interop methods,
-                    // we don't want to treat the async variant as a COM Interop method
-                    // (as it isn't, it's a transient IL method).
+                    // Don't treat the async variant of special method kinds as
+                    // the special method kind.
+                    // The async variant methods are always IL methods with a transient implementation.
                     asyncVariantType = mcIL;
                 }
-#endif // FEATURE_COMINTEROP
 
                 Signature newMemberSig(pNewMemberSignature, cAsyncThunkMemberSignature);
                 pNewMethod = new (GetStackingAllocator()) bmtMDMethod(

src/libraries/System.Private.CoreLib/src/Resources/Strings.resx

@@ -3107,6 +3107,9 @@
   <data name="NotSupported_NonReflectedType" xml:space="preserve">
     <value>Not supported in a non-reflected type.</value>
   </data>
+  <data name="InvalidProgram_AsyncMethod" xml:space="preserve">
+    <value>Async methods with UnmanagedCallersOnlyAttribute are invalid.</value>
+  </data>
   <data name="InvalidProgram_NonStaticMethod" xml:space="preserve">
     <value>Non-static methods with UnmanagedCallersOnlyAttribute are invalid.</value>
   </data>

src/tests/Interop/COM/RuntimeAsync/RuntimeAsync.cs

@@ -58,17 +58,36 @@ static async Task TestAsyncMethod(ITaskComServer_AsDispatchOnly obj)
             }
         }
     }
+
+    [Fact]
+    public static void TaskReturningPInvokeWithComMarshalling()
+    {
+        Task originalTask = new(() => {});
+        Task result = RunTask(originalTask);
+
+        originalTask.Start();
+
+        result.GetAwaiter().GetResult();
+
+        static async Task RunTask(Task task)
+        {
+            await RuntimeAsyncNative.PassThroughTask(task);
+        }
+    }
 }
 
 public static class RuntimeAsyncNative
 {
-    [DllImport("RuntimeAsyncNative")]
+    [DllImport(nameof(RuntimeAsyncNative))]
     [return: MarshalAs(UnmanagedType.U1)]
     public static extern bool ValidateSlotLayoutForDefaultInterface([MarshalAs(UnmanagedType.Interface)] object comObject, int expectedIntValue, float expectedFloatValue);
 
-    [DllImport("RuntimeAsyncNative")]
+    [DllImport(nameof(RuntimeAsyncNative))]
     [return: MarshalAs(UnmanagedType.U1)]
     public static extern bool ValidateSlotLayoutForInterface([MarshalAs(UnmanagedType.Interface)] object comObject, float expectedFloatValue);
+
+    [DllImport(nameof(RuntimeAsyncNative))]
+    public static extern Task PassThroughTask(Task task);
 }
 
 [ComVisible(true)]

src/tests/Interop/COM/RuntimeAsync/RuntimeAsyncNative.cpp

@@ -79,3 +79,9 @@ extern "C" DLL_EXPORT bool STDMETHODCALLTYPE ValidateSlotLayoutForInterface(IUnk
 
     return true;
 }
+
+extern "C" DLL_EXPORT IUnknown* STDMETHODCALLTYPE PassThroughTask(IUnknown* pUnk)
+{
+    pUnk->AddRef();
+    return pUnk;
+}

src/tests/Interop/UnmanagedCallersOnly/InvalidCallbacks.il

@@ -305,3 +305,41 @@
         IL_0001: ret
     }
 }
+
+.class public auto ansi beforefieldinit InvalidCSharp.RuntimeAsyncUnmanagedCallersOnly
+    extends [System.Runtime]System.Object
+{
+    .method public hidebysig specialname rtspecialname
+        instance void .ctor () cil managed
+    {
+        .maxstack 8
+        ldarg.0
+        call instance void [System.Runtime]System.Object::.ctor()
+        ret
+    }
+
+    .method public hidebysig static
+        class [System.Runtime]System.Threading.Tasks.Task AsyncMethodReturningTask (
+        ) cil managed async
+    {
+        .custom instance void [System.Runtime.InteropServices]System.Runtime.InteropServices.UnmanagedCallersOnlyAttribute::.ctor() = (
+            01 00 00 00
+        )
+        .maxstack 8
+
+        IL_0001: ret
+    }
+
+    .method public hidebysig static
+        int32 AsyncMethodWithBlittableReturnType (
+        ) cil managed async
+    {
+        .custom instance void [System.Runtime.InteropServices]System.Runtime.InteropServices.UnmanagedCallersOnlyAttribute::.ctor() = (
+            01 00 00 00
+        )
+        .maxstack 8
+
+        IL_0000: ldc.i4.0
+        IL_0001: ret
+    }
+}