Added support for ldvirtftn instruction to CppCodeGen (#4556)

1 files changed, 84 insertions, 44 deletions

diff --git a/src/ILCompiler.CppCodeGen/src/CppCodeGen/ILToCppImporter.cs b/src/ILCompiler.CppCodeGen/src/CppCodeGen/ILToCppImporter.cs
index 88faf7d41..9f9d90a66 100644
--- a/src/ILCompiler.CppCodeGen/src/CppCodeGen/ILToCppImporter.cs
+++ b/src/ILCompiler.CppCodeGen/src/CppCodeGen/ILToCppImporter.cs
@@ -1046,44 +1046,15 @@ namespace Internal.IL
                 ExpressionEntry v = (ExpressionEntry)_stack[_stack.Top - (methodSignature.Length + 1)];
 
                 string typeDefName = _writer.GetCppMethodName(method);
-                _writer.AppendSignatureTypeDef(_builder,  typeDefName, method.Signature, method.OwningType);
+                _writer.AppendSignatureTypeDef(_builder, typeDefName, method.Signature, method.OwningType);
 
                 string functionPtr = NewTempName();
                 AppendEmptyLine();
 
                 Append("void*");
                 Append(functionPtr);
-                Append(" = (void*) ((");
-                Append(typeDefName);
-                // Call method to find implementation address
-                Append(") System_Private_CoreLib::System::Runtime::DispatchResolve::FindInterfaceMethodImplementationTarget(");
-
-                // Get EEType of current object (interface implementation)
-                Append("::System_Private_CoreLib::System::Object::get_EEType((::System_Private_CoreLib::System::Object*)");
-                Append(v.Name);
-                Append(")");
-
-                Append(", ");
-
-                // Get EEType of interface
-                Append("((::System_Private_CoreLib::Internal::Runtime::EEType *)(");
-                Append(_writer.GetCppTypeName(method.OwningType));
-                Append("::__getMethodTable()))");
-
-                Append(", ");
-
-                // Get slot of implementation
-                Append("(uint16_t)");
-                Append("(");
-                Append(_writer.GetCppTypeName(method.OwningType));
-                Append("::");
-                Append("__getslot__");
-                Append(_writer.GetCppMethodName(method));
-                Append("(");
-                Append(v.Name);
-                Append("))");
-
-                Append("));");
+                Append(" = (void*) ");
+                GetFunctionPointerForInterfaceMethod(method, v, typeDefName);
 
                 PushExpression(StackValueKind.ByRef, functionPtr);
             }
@@ -1236,6 +1207,41 @@ namespace Internal.IL
             }
         }
 
+        private void GetFunctionPointerForInterfaceMethod(MethodDesc method, ExpressionEntry v, string typeDefName)
+        {
+            Append("((");
+            Append(typeDefName);
+            // Call method to find implementation address
+            Append(") System_Private_CoreLib::System::Runtime::DispatchResolve::FindInterfaceMethodImplementationTarget(");
+
+            // Get EEType of current object (interface implementation)
+            Append("::System_Private_CoreLib::System::Object::get_EEType((::System_Private_CoreLib::System::Object*)");
+            Append(v.Name);
+            Append(")");
+
+            Append(", ");
+
+            // Get EEType of interface
+            Append("((::System_Private_CoreLib::Internal::Runtime::EEType *)(");
+            Append(_writer.GetCppTypeName(method.OwningType));
+            Append("::__getMethodTable()))");
+
+            Append(", ");
+
+            // Get slot of implementation
+            Append("(uint16_t)");
+            Append("(");
+            Append(_writer.GetCppTypeName(method.OwningType));
+            Append("::");
+            Append("__getslot__");
+            Append(_writer.GetCppMethodName(method));
+            Append("(");
+            Append(v.Name);
+            Append("))");
+
+            Append("));");
+        }
+
         private void PassCallArguments(MethodSignature methodSignature, TypeDesc thisArgument)
         {
             int signatureLength = methodSignature.Length;
@@ -1325,22 +1331,51 @@ namespace Internal.IL
         {
             MethodDesc method = (MethodDesc)_methodIL.GetObject(token);
 
-            if (opCode == ILOpcode.ldvirtftn)
+            if (opCode == ILOpcode.ldvirtftn && method.IsVirtual && method.OwningType.IsInterface)
             {
-                if (method.IsVirtual)
-                    throw new NotImplementedException();
-            }
+                AddVirtualMethodReference(method);
+                var entry = new LdTokenEntry<MethodDesc>(StackValueKind.NativeInt, NewTempName(), method);
+                ExpressionEntry v = (ExpressionEntry)_stack.Pop();
+                string typeDefName = _writer.GetCppMethodName(method);
+                _writer.AppendSignatureTypeDef(_builder, typeDefName, method.Signature, method.OwningType);
 
-            AddMethodReference(method);
+                AppendEmptyLine();
 
-            var entry = new LdTokenEntry<MethodDesc>(StackValueKind.NativeInt, NewTempName(), method);
-            PushTemp(entry);
-            Append("(intptr_t)&");
-            Append(_writer.GetCppTypeName(method.OwningType));
-            Append("::");
-            Append(_writer.GetCppMethodName(method));
+                PushTemp(entry);
+                Append("(intptr_t) ");
+                GetFunctionPointerForInterfaceMethod(method, v, typeDefName);
+            }
+            else
+            {
+                AddMethodReference(method);
+                var entry = new LdTokenEntry<MethodDesc>(StackValueKind.NativeInt, NewTempName(), method);
+                
+                if (opCode == ILOpcode.ldvirtftn && method.IsVirtual)
+                {
+                    //ldvirtftn requires an object instance, we have to pop one off the stack
+                    //then call the associated getslot method passing in the object instance to get the real function pointer
+                    ExpressionEntry v = (ExpressionEntry)_stack.Pop();
+                    PushTemp(entry);
+                    Append("(intptr_t)");
+                    Append(_writer.GetCppTypeName(method.OwningType));
+                    Append("::__getslot__");
+                    Append(_writer.GetCppMethodName(method));
+                    Append("(");
+                    Append(v.Name);
+                    Append(")");
+                    AppendSemicolon();
+                }
+                else
+                {
+                    PushTemp(entry);
+                    Append("(intptr_t)&");
+                    Append(_writer.GetCppTypeName(method.OwningType));
+                    Append("::");
+                    Append(_writer.GetCppMethodName(method));
 
-            AppendSemicolon();
+                    AppendSemicolon();
+                }
+            }
         }
 
         private void ImportLoadInt(long value, StackValueKind kind)
@@ -2675,6 +2710,11 @@ namespace Internal.IL
             _dependencies.Add(_nodeFactory.MethodEntrypoint(method));
         }
 
+        private void AddVirtualMethodReference(MethodDesc method)
+        {
+            _dependencies.Add(_nodeFactory.VirtualMethodUse(method));
+        }
+
         private void AddFieldReference(FieldDesc field)
         {
             if (field.IsStatic)