Remove Helper Method Frames (HMF) from Reflection

src/coreclr/System.Private.CoreLib/src/System/Reflection/RuntimeCustomAttributeData.cs

@@ -1085,7 +1085,7 @@ public CustomAttributeType(RuntimeType parameterType)
 
             if (encodedType == CustomAttributeEncoding.Array)
             {
-                parameterType = (RuntimeType)parameterType.GetElementType();
+                parameterType = (RuntimeType)parameterType.GetElementType()!;
                 encodedArrayType = RuntimeCustomAttributeData.TypeToCustomAttributeEncoding(parameterType);
             }
 

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

@@ -30,7 +30,8 @@ internal RuntimeType GetTypeChecked() =>
         /// </summary>
         /// <param name="value">An IntPtr handle to a RuntimeType to create a <see cref="RuntimeTypeHandle"/> object from.</param>
         /// <returns>A new <see cref="RuntimeTypeHandle"/> object that corresponds to the value parameter.</returns>
-        public static RuntimeTypeHandle FromIntPtr(IntPtr value) => new RuntimeTypeHandle(GetTypeFromHandle(value));
+        public static RuntimeTypeHandle FromIntPtr(IntPtr value) =>
+            new RuntimeTypeHandle(value == IntPtr.Zero ? null : GetRuntimeTypeFromHandle(value));
 
         [LibraryImport(RuntimeHelpers.QCall, EntryPoint = "RuntimeTypeHandle_GetTypeFromHandleSlow")]
         private static partial void GetTypeFromHandleSlow(
@@ -48,13 +49,8 @@ private static RuntimeType GetTypeFromHandleSlow(IntPtr handle)
         [MethodImpl(MethodImplOptions.InternalCall)]
         private static extern RuntimeType? GetTypeFromHandleIfExists(IntPtr handle);
 
-        private static RuntimeType? GetTypeFromHandle(IntPtr handle)
+        private static RuntimeType GetRuntimeTypeFromHandle(IntPtr handle)
         {
-            if (handle == IntPtr.Zero)
-            {
-                return null;
-            }
-
             return GetTypeFromHandleIfExists(handle) ?? GetTypeFromHandleSlow(handle);
         }
 
@@ -386,7 +382,20 @@ public ModuleHandle GetModuleHandle()
         internal static extern TypeAttributes GetAttributes(RuntimeType type);
 
         [MethodImpl(MethodImplOptions.InternalCall)]
-        internal static extern RuntimeType GetElementType(RuntimeType type);
+        private static extern IntPtr GetElementTypeHandle(IntPtr handle);
+
+        internal static RuntimeType? GetElementType(RuntimeType type)
+        {
+            IntPtr handle = GetElementTypeHandle(type.GetUnderlyingNativeHandle());
+            if (handle == IntPtr.Zero)
+            {
+                return null;
+            }
+
+            RuntimeType result = GetRuntimeTypeFromHandle(handle);
+            GC.KeepAlive(type);
+            return result;
+        }
 
         [MethodImpl(MethodImplOptions.InternalCall)]
         internal static extern bool CompareCanonicalHandles(RuntimeType left, RuntimeType right);
@@ -565,8 +574,38 @@ internal static unsafe MdUtf8String GetUtf8Name(RuntimeType type)
         [MethodImpl(MethodImplOptions.InternalCall)]
         internal static extern bool CanCastTo(RuntimeType type, RuntimeType target);
 
-        [MethodImpl(MethodImplOptions.InternalCall)]
-        internal static extern RuntimeType GetDeclaringType(RuntimeType type);
+        [LibraryImport(RuntimeHelpers.QCall, EntryPoint = "RuntimeTypeHandle_GetDeclaringTypeHandleForGenericVariable")]
+        private static partial IntPtr GetDeclaringTypeHandleForGenericVariable(IntPtr typeHandle);
+
+        [LibraryImport(RuntimeHelpers.QCall, EntryPoint = "RuntimeTypeHandle_GetDeclaringTypeHandle")]
+        private static partial IntPtr GetDeclaringTypeHandle(IntPtr typeHandle);
+
+        internal static unsafe RuntimeType? GetDeclaringType(RuntimeType type)
+        {
+            IntPtr retTypeHandle = IntPtr.Zero;
+            TypeHandle typeHandle = type.GetNativeTypeHandle();
+            if (typeHandle.IsTypeDesc)
+            {
+                CorElementType elementType = (CorElementType)typeHandle.GetCorElementType();
+                if (elementType is CorElementType.ELEMENT_TYPE_VAR or CorElementType.ELEMENT_TYPE_MVAR)
+                {
+                    retTypeHandle = GetDeclaringTypeHandleForGenericVariable(type.GetUnderlyingNativeHandle());
+                }
+            }
+            else
+            {
+                retTypeHandle = GetDeclaringTypeHandle(type.GetUnderlyingNativeHandle());
+            }
+
+            if (retTypeHandle == IntPtr.Zero)
+            {
+                return null;
+            }
+
+            RuntimeType result = GetRuntimeTypeFromHandle(retTypeHandle);
+            GC.KeepAlive(type);
+            return result;
+        }
 
         [MethodImpl(MethodImplOptions.InternalCall)]
         internal static extern IRuntimeMethodInfo GetDeclaringMethod(RuntimeType type);
@@ -928,7 +967,14 @@ internal static string ConstructInstantiation(IRuntimeMethodInfo method, TypeNam
         }
 
         [MethodImpl(MethodImplOptions.InternalCall)]
-        internal static extern RuntimeType GetDeclaringType(RuntimeMethodHandleInternal method);
+        private static extern unsafe MethodTable* GetMethodTable(RuntimeMethodHandleInternal method);
+
+        internal static unsafe RuntimeType GetDeclaringType(RuntimeMethodHandleInternal method)
+        {
+            Debug.Assert(!method.IsNullHandle());
+            MethodTable* pMT = GetMethodTable(method);
+            return RuntimeTypeHandle.GetRuntimeType(pMT);
+        }
 
         internal static RuntimeType GetDeclaringType(IRuntimeMethodInfo method)
         {

src/coreclr/System.Private.CoreLib/src/System/RuntimeType.CoreCLR.cs

@@ -1038,7 +1038,7 @@ private RuntimeType[] PopulateInterfaces(Filter filter)
 
                         if (ReflectedType.IsSZArray)
                         {
-                            RuntimeType arrayType = (RuntimeType)ReflectedType.GetElementType();
+                            RuntimeType arrayType = (RuntimeType)ReflectedType.GetElementType()!;
 
                             if (!arrayType.IsPointer)
                             {
@@ -1597,7 +1597,7 @@ internal TypeCode TypeCode
                 if (m_enclosingType == null)
                 {
                     // Use void as a marker of null enclosing type
-                    RuntimeType enclosingType = RuntimeTypeHandle.GetDeclaringType(GetRuntimeType());
+                    RuntimeType? enclosingType = RuntimeTypeHandle.GetDeclaringType(GetRuntimeType());
                     Debug.Assert(enclosingType != typeof(void));
                     m_enclosingType = enclosingType ?? (RuntimeType)typeof(void);
                 }

src/coreclr/vm/ecalllist.h

@@ -83,12 +83,11 @@ FCFuncEnd()
 
 FCFuncStart(gCOMTypeHandleFuncs)
     FCFuncElement("GetDeclaringMethod", RuntimeTypeHandle::GetDeclaringMethod)
-    FCFuncElement("GetDeclaringType", RuntimeTypeHandle::GetDeclaringType)
     FCFuncElement("GetFirstIntroducedMethod", RuntimeTypeHandle::GetFirstIntroducedMethod)
     FCFuncElement("GetNextIntroducedMethod", RuntimeTypeHandle::GetNextIntroducedMethod)
     FCFuncElement("GetAssemblyIfExists", RuntimeTypeHandle::GetAssemblyIfExists)
     FCFuncElement("GetModuleIfExists", RuntimeTypeHandle::GetModuleIfExists)
-    FCFuncElement("GetElementType", RuntimeTypeHandle::GetElementType)
+    FCFuncElement("GetElementTypeHandle", RuntimeTypeHandle::GetElementTypeHandle)
     FCFuncElement("GetArrayRank", RuntimeTypeHandle::GetArrayRank)
     FCFuncElement("GetToken", RuntimeTypeHandle::GetToken)
     FCFuncElement("GetUtf8NameInternal", RuntimeTypeHandle::GetUtf8Name)
@@ -152,7 +151,7 @@ FCFuncStart(gRuntimeMethodHandle)
     FCFuncElement("ReboxToNullable", RuntimeMethodHandle::ReboxToNullable)
     FCFuncElement("GetImplAttributes", RuntimeMethodHandle::GetImplAttributes)
     FCFuncElement("GetAttributes", RuntimeMethodHandle::GetAttributes)
-    FCFuncElement("GetDeclaringType", RuntimeMethodHandle::GetDeclaringType)
+    FCFuncElement("GetMethodTable", RuntimeMethodHandle::GetMethodTable)
     FCFuncElement("GetSlot", RuntimeMethodHandle::GetSlot)
     FCFuncElement("GetMethodDef", RuntimeMethodHandle::GetMethodDef)
     FCFuncElement("GetUtf8NameInternal", RuntimeMethodHandle::GetUtf8Name)

src/coreclr/vm/qcallentrypoints.cpp

@@ -127,6 +127,8 @@ static const Entry s_QCall[] =
     DllImportEntry(RuntimeTypeHandle_GetNumVirtualsAndStaticVirtuals)
     DllImportEntry(RuntimeTypeHandle_VerifyInterfaceIsImplemented)
     DllImportEntry(RuntimeTypeHandle_GetInterfaceMethodImplementation)
+    DllImportEntry(RuntimeTypeHandle_GetDeclaringTypeHandleForGenericVariable)
+    DllImportEntry(RuntimeTypeHandle_GetDeclaringTypeHandle)
     DllImportEntry(RuntimeTypeHandle_IsVisible)
     DllImportEntry(RuntimeTypeHandle_ConstructName)
     DllImportEntry(RuntimeTypeHandle_GetInstantiation)