Remove built-in COM interop support from Mono runtime (#97789)

src/mono/CMakeLists.txt

@@ -84,8 +84,6 @@ if(ENABLE_MINIMAL)
   process_enable_minimal()
 endif()
 
-set(DISABLE_COM 1)
-
 # Dependencies between options
 if(ENABLE_INTERP_LIB)
   set(DISABLE_INTERPRETER 1)

src/mono/System.Private.CoreLib/src/System/RuntimeTypeHandle.cs

@@ -205,9 +205,6 @@ internal static bool HasElementType(RuntimeType type)
         [MethodImplAttribute(MethodImplOptions.InternalCall)]
         internal static extern bool HasInstantiation(QCallTypeHandle type);
 
-        [MethodImplAttribute(MethodImplOptions.InternalCall)]
-        internal static extern bool IsComObject(QCallTypeHandle type);
-
         [MethodImplAttribute(MethodImplOptions.InternalCall)]
         internal static extern bool IsInstanceOfType(QCallTypeHandle type, [NotNullWhen(true)] object? o);
 
@@ -234,10 +231,13 @@ internal static bool HasInstantiation(RuntimeType type)
             return HasInstantiation(new QCallTypeHandle(ref type));
         }
 
+#pragma warning disable IDE0060
         internal static bool IsComObject(RuntimeType type, bool isGenericCOM)
         {
-            return isGenericCOM ? false : IsComObject(new QCallTypeHandle(ref type));
+            // Mono runtime doesn't support built-in COM.
+            return false;
         }
+#pragma warning restore IDE0060
 
 #pragma warning disable IDE0060
         internal static bool IsEquivalentTo(RuntimeType rtType1, RuntimeType rtType2)

src/mono/cmake/config.h.in

@@ -235,9 +235,6 @@
 /* Disable support debug logging */
 #cmakedefine DISABLE_LOGGING 1
 
-/* Disable COM support */
-#cmakedefine DISABLE_COM 1
-
 /* Disable advanced SSA JIT optimizations */
 #cmakedefine DISABLE_SSA 1
 

src/mono/cmake/options.cmake

@@ -6,7 +6,6 @@ option (DISABLE_AOT "Disable AOT Compiler")
 option (DISABLE_DEBUG "Disable runtime debugging support")
 option (DISABLE_REFLECTION_EMIT "Disable reflection emit support")
 option (DISABLE_LOGGING "Disable support debug logging")
-option (DISABLE_COM "Disable COM support")
 option (DISABLE_SSA "Disable advanced SSA JIT optimizations")
 option (DISABLE_JIT "Disable the JIT, only full-aot mode or interpreter will be supported by the runtime.")
 option (DISABLE_INTERPRETER "Disable the interpreter.")

src/mono/mono/component/marshal-ilgen.c

@@ -414,15 +414,6 @@ emit_marshal_array_ilgen (EmitMarshalContext *m, int argnum, MonoType *t,
 		switch (spec->native) {
 		case MONO_NATIVE_LPARRAY:
 			break;
-		case MONO_NATIVE_SAFEARRAY:
-#ifndef DISABLE_COM
-			if (spec->data.safearray_data.elem_type != MONO_VARIANT_VARIANT) {
-				char *msg = g_strdup ("Only SAFEARRAY(VARIANT) marshalling to managed code is implemented.");
-				cb_to_mono->methodBuilder.emit_exception_marshal_directive (mb, msg);
-				return conv_arg;
-			}
-			return mono_cominterop_emit_marshal_safearray (m, argnum, t, spec, conv_arg, conv_arg_type, action);
-#endif
 		default: {
 			char *msg = g_strdup ("Unsupported array type marshalling to managed code.");
 			cb_to_mono->methodBuilder.emit_exception_marshal_directive (mb, msg);
@@ -2618,108 +2609,6 @@ emit_marshal_object_ilgen (EmitMarshalContext *m, int argnum, MonoType *t,
 	return conv_arg;
 }
 
-static int
-emit_marshal_variant_ilgen (EmitMarshalContext *m, int argnum, MonoType *t,
-			MonoMarshalSpec *spec,
-			int conv_arg, MonoType **conv_arg_type,
-			MarshalAction action)
-{
-#ifndef DISABLE_COM
-	MonoMethodBuilder *mb = m->mb;
-	MonoType *variant_type = m_class_get_byval_arg (mono_class_get_variant_class ());
-	MonoType *variant_type_byref = mono_class_get_byref_type (mono_class_get_variant_class ());
-	MonoType *object_type = cb_to_mono->get_object_type ();
-
-	switch (action) {
-	case MARSHAL_ACTION_CONV_IN: {
-		conv_arg = cb_to_mono->methodBuilder.add_local (mb, variant_type);
-
-		if (m_type_is_byref (t))
-			*conv_arg_type = variant_type_byref;
-		else
-			*conv_arg_type = variant_type;
-
-		if (m_type_is_byref (t) && !(t->attrs & PARAM_ATTRIBUTE_IN) && t->attrs & PARAM_ATTRIBUTE_OUT)
-			break;
-
-		cb_to_mono->methodBuilder.emit_ldarg (mb, argnum);
-		if (m_type_is_byref (t))
-			cb_to_mono->methodBuilder.emit_byte(mb, CEE_LDIND_REF);
-		cb_to_mono->methodBuilder.emit_ldloc_addr (mb, conv_arg);
-		cb_to_mono->methodBuilder.emit_managed_call (mb, mono_get_Marshal_GetNativeVariantForObject (), NULL);
-		break;
-	}
-
-	case MARSHAL_ACTION_CONV_OUT: {
-		if (m_type_is_byref (t) && (t->attrs & PARAM_ATTRIBUTE_OUT || !(t->attrs & PARAM_ATTRIBUTE_IN))) {
-			cb_to_mono->methodBuilder.emit_ldarg (mb, argnum);
-			cb_to_mono->methodBuilder.emit_ldloc_addr (mb, conv_arg);
-			cb_to_mono->methodBuilder.emit_managed_call (mb, mono_get_Marshal_GetObjectForNativeVariant (), NULL);
-			cb_to_mono->methodBuilder.emit_byte (mb, CEE_STIND_REF);
-		}
-
-		cb_to_mono->methodBuilder.emit_ldloc_addr (mb, conv_arg);
-		cb_to_mono->methodBuilder.emit_managed_call (mb, mono_get_Variant_Clear (), NULL);
-		break;
-	}
-
-	case MARSHAL_ACTION_PUSH:
-		if (m_type_is_byref (t))
-			cb_to_mono->methodBuilder.emit_ldloc_addr (mb, conv_arg);
-		else
-			cb_to_mono->methodBuilder.emit_ldloc (mb, conv_arg);
-		break;
-
-	case MARSHAL_ACTION_CONV_RESULT: {
-		char *msg = g_strdup ("Marshalling of VARIANT not supported as a return type.");
-		cb_to_mono->methodBuilder.emit_exception_marshal_directive (mb, msg);
-		break;
-	}
-
-	case MARSHAL_ACTION_MANAGED_CONV_IN: {
-		conv_arg = cb_to_mono->methodBuilder.add_local (mb, object_type);
-
-		if (m_type_is_byref (t))
-			*conv_arg_type = variant_type_byref;
-		else
-			*conv_arg_type = variant_type;
-
-		if (m_type_is_byref (t) && !(t->attrs & PARAM_ATTRIBUTE_IN) && t->attrs & PARAM_ATTRIBUTE_OUT)
-			break;
-
-		if (m_type_is_byref (t))
-			cb_to_mono->methodBuilder.emit_ldarg (mb, argnum);
-		else
-			cb_to_mono->methodBuilder.emit_ldarg_addr (mb, argnum);
-		cb_to_mono->methodBuilder.emit_managed_call (mb, mono_get_Marshal_GetObjectForNativeVariant (), NULL);
-		cb_to_mono->methodBuilder.emit_stloc (mb, conv_arg);
-		break;
-	}
-
-	case MARSHAL_ACTION_MANAGED_CONV_OUT: {
-		if (m_type_is_byref (t) && (t->attrs & PARAM_ATTRIBUTE_OUT || !(t->attrs & PARAM_ATTRIBUTE_IN))) {
-			cb_to_mono->methodBuilder.emit_ldloc (mb, conv_arg);
-			cb_to_mono->methodBuilder.emit_ldarg (mb, argnum);
-			cb_to_mono->methodBuilder.emit_managed_call (mb, mono_get_Marshal_GetNativeVariantForObject (), NULL);
-		}
-		break;
-	}
-
-	case MARSHAL_ACTION_MANAGED_CONV_RESULT: {
-		char *msg = g_strdup ("Marshalling of VARIANT not supported as a return type.");
-		cb_to_mono->methodBuilder.emit_exception_marshal_directive (mb, msg);
-		break;
-	}
-
-	default:
-		g_assert_not_reached ();
-	}
-#endif /* DISABLE_COM */
-
-	return conv_arg;
-}
-
-
 static int
 emit_marshal_ilgen (EmitMarshalContext *m, int argnum, MonoType *t,
 		MonoMarshalSpec *spec, int conv_arg,
@@ -2741,23 +2630,6 @@ emit_marshal_ilgen (EmitMarshalContext *m, int argnum, MonoType *t,
 		return emit_marshal_string_ilgen (m, argnum, t, spec, conv_arg, conv_arg_type, action);
 	case MONO_TYPE_CLASS:
 	case MONO_TYPE_OBJECT:
-#if !defined(DISABLE_COM)
-		if (spec && spec->native == MONO_NATIVE_STRUCT)
-			return emit_marshal_variant_ilgen (m, argnum, t, spec, conv_arg, conv_arg_type, action);
-#endif
-
-#if !defined(DISABLE_COM)
-		if ((spec && (spec->native == MONO_NATIVE_IUNKNOWN ||
-			spec->native == MONO_NATIVE_IDISPATCH ||
-			spec->native == MONO_NATIVE_INTERFACE)) ||
-			(t->type == MONO_TYPE_CLASS && mono_cominterop_is_interface(t->data.klass)))
-			return mono_cominterop_emit_marshal_com_interface (m, argnum, t, spec, conv_arg, conv_arg_type, action);
-		if (spec && (spec->native == MONO_NATIVE_SAFEARRAY) &&
-			(spec->data.safearray_data.elem_type == MONO_VARIANT_VARIANT) &&
-			((action == MARSHAL_ACTION_CONV_OUT) || (action == MARSHAL_ACTION_CONV_IN) || (action == MARSHAL_ACTION_PUSH)))
-			return mono_cominterop_emit_marshal_safearray (m, argnum, t, spec, conv_arg, conv_arg_type, action);
-#endif
-
 		if (cb_to_mono->try_get_safehandle_class () != NULL && t->data.klass &&
 		    cb_to_mono->is_subclass_of_internal (t->data.klass,  cb_to_mono->try_get_safehandle_class (), FALSE))
 			return emit_marshal_safehandle_ilgen (m, argnum, t, spec, conv_arg, conv_arg_type, action);

src/mono/mono/eventpipe/ep-rt-mono-runtime-provider.c

@@ -187,7 +187,7 @@ typedef struct _AssemblyEventData AssemblyEventData;
 typedef enum {
 	TYPE_FLAGS_DELEGATE = 0x1,
 	TYPE_FLAGS_FINALIZABLE = 0x2,
-	TYPE_FLAGS_EXTERNALLY_IMPLEMENTED_COM_OBJECT = 0x4,
+	// unused = 0x4,
 	TYPE_FLAGS_ARRAY = 0x8,
 
 	TYPE_FLAGS_ARRAY_RANK_MASK = 0x3F00,
@@ -1547,8 +1547,6 @@ bulk_type_log_single_type (
 		val->fixed_sized_data.flags |= TYPE_FLAGS_FINALIZABLE;
 	if (m_class_is_delegate (klass))
 		val->fixed_sized_data.flags |= TYPE_FLAGS_DELEGATE;
-	if (mono_class_is_com_object (klass))
-		val->fixed_sized_data.flags |= TYPE_FLAGS_EXTERNALLY_IMPLEMENTED_COM_OBJECT;
 	val->fixed_sized_data.cor_element_type = (uint8_t)mono_underlying_type->type;
 
 	// Sets val variable sized parameter type data, type_parameters_count, and mono_type_parameters associated

src/mono/mono/metadata/CMakeLists.txt

@@ -61,8 +61,6 @@ set(metadata_common_sources
     class-private-definition.h
     class-accessors.c
     class-setup-vtable.c
-    cominterop.c
-    cominterop.h
     components.h
     components.c
     debug-helpers.c

src/mono/mono/metadata/class-accessors.c

@@ -437,16 +437,6 @@ mono_class_set_declsec_flags (MonoClass *klass, guint32 value)
 	mono_property_bag_add (m_class_get_infrequent_data (klass), prop);
 }
 
-void
-mono_class_set_is_com_object (MonoClass *klass)
-{
-#ifndef DISABLE_COM
-	mono_loader_lock ();
-	klass->is_com_object = 1;
-	mono_loader_unlock ();
-#endif
-}
-
 void
 mono_class_set_is_simd_type (MonoClass *klass, gboolean is_simd)
 {

src/mono/mono/metadata/class-getters.h

@@ -41,7 +41,6 @@ MONO_CLASS_GETTER(m_class_has_cctor, gboolean,  , MonoClass, has_cctor)
 MONO_CLASS_GETTER(m_class_has_references, gboolean, , MonoClass, has_references)
 MONO_CLASS_GETTER(m_class_has_static_refs, gboolean, , MonoClass, has_static_refs)
 MONO_CLASS_GETTER(m_class_has_no_special_static_fields, gboolean, , MonoClass, no_special_static_fields)
-MONO_CLASS_GETTER(m_class_is_com_object, gboolean, , MonoClass, is_com_object)
 MONO_CLASS_GETTER(m_class_is_nested_classes_inited, gboolean, , MonoClass, nested_classes_inited)
 MONO_CLASS_GETTER(m_class_get_class_kind, guint8, , MonoClass, class_kind)
 MONO_CLASS_GETTER(m_class_is_interfaces_inited, gboolean, , MonoClass, interfaces_inited)

src/mono/mono/metadata/class-init.c

@@ -3188,20 +3188,6 @@ mono_class_init_checked (MonoClass *klass, MonoError *error)
 	return success;
 }
 
-#ifndef DISABLE_COM
-/*
- * COM initialization is delayed until needed.
- * However when a [ComImport] attribute is present on a type it will trigger
- * the initialization. This is not a problem unless the BCL being executed
- * lacks the types that COM depends on (e.g. Variant on Silverlight).
- */
-static void
-init_com_from_comimport (MonoClass *klass)
-{
-	/* FIXME : we should add an extra checks to ensure COM can be initialized properly before continuing */
-}
-#endif /*DISABLE_COM*/
-
 /*
  * LOCKING: this assumes the loader lock is held
  */
@@ -3226,14 +3212,6 @@ mono_class_setup_parent (MonoClass *klass, MonoClass *parent)
 	}
 
 	if (!MONO_CLASS_IS_INTERFACE_INTERNAL (klass)) {
-		/* Imported COM Objects always derive from __ComObject. */
-#ifndef DISABLE_COM
-		if (MONO_CLASS_IS_IMPORT (klass)) {
-			init_com_from_comimport (klass);
-			if (parent == mono_defaults.object_class)
-				parent = mono_class_get_com_object_class ();
-		}
-#endif
 		if (!parent) {
 			/* set the parent to something useful and safe, but mark the type as broken */
 			parent = mono_defaults.object_class;
@@ -3254,9 +3232,6 @@ mono_class_setup_parent (MonoClass *klass, MonoClass *parent)
 
 		klass->delegate  = parent->delegate;
 
-		if (MONO_CLASS_IS_IMPORT (klass) || mono_class_is_com_object (parent))
-			mono_class_set_is_com_object (klass);
-
 		if (system_namespace) {
 			if (klass->name [0] == 'D' && !strcmp (klass->name, "Delegate"))
 				klass->delegate  = 1;
@@ -3270,11 +3245,6 @@ mono_class_setup_parent (MonoClass *klass, MonoClass *parent)
 		}
 		/*klass->enumtype = klass->parent->enumtype; */
 	} else {
-		/* initialize com types if COM interfaces are present */
-#ifndef DISABLE_COM
-		if (MONO_CLASS_IS_IMPORT (klass))
-			init_com_from_comimport (klass);
-#endif
 		klass->parent = NULL;
 	}
 

src/mono/mono/metadata/class-internals.h

@@ -331,13 +331,6 @@ int mono_class_interface_match (const uint8_t *bitmap, int id);
 
 #define MONO_VTABLE_AVAILABLE_GC_BITS 4
 
-#ifdef DISABLE_COM
-#define mono_class_is_com_object(klass) (FALSE)
-#else
-#define mono_class_is_com_object(klass) (m_class_is_com_object (klass))
-#endif
-
-
 MONO_API int mono_class_interface_offset (MonoClass *klass, MonoClass *itf);
 MONO_COMPONENT_API int mono_class_interface_offset_with_variance (MonoClass *klass, MonoClass *itf, gboolean *non_exact_match);
 
@@ -979,16 +972,6 @@ mono_class_try_get_##shortname##_class (void)	\
 
 GENERATE_TRY_GET_CLASS_WITH_CACHE_DECL (safehandle)
 
-#ifndef DISABLE_COM
-
-GENERATE_GET_CLASS_WITH_CACHE_DECL (interop_proxy)
-GENERATE_GET_CLASS_WITH_CACHE_DECL (idispatch)
-GENERATE_GET_CLASS_WITH_CACHE_DECL (iunknown)
-GENERATE_GET_CLASS_WITH_CACHE_DECL (com_object)
-GENERATE_GET_CLASS_WITH_CACHE_DECL (variant)
-
-#endif
-
 MonoClass* mono_class_get_appdomain_class (void);
 
 GENERATE_GET_CLASS_WITH_CACHE_DECL (appdomain_unloaded_exception)
@@ -1370,9 +1353,6 @@ mono_class_get_declsec_flags (MonoClass *klass);
 void
 mono_class_set_declsec_flags (MonoClass *klass, guint32 value);
 
-void
-mono_class_set_is_com_object (MonoClass *klass);
-
 void
 mono_class_set_weak_bitmap (MonoClass *klass, int nbits, gsize *bits);
 

src/mono/mono/metadata/class-private-definition.h

@@ -66,12 +66,7 @@ struct _MonoClass {
 	guint has_ref_fields  : 1; /* it has byref fields */
 	guint has_static_refs : 1; /* it has static fields that are GC-tracked */
 	guint no_special_static_fields : 1; /* has no thread/context static fields */
-	/* directly or indirectly derives from ComImport attributed class.
-	 * this means we need to create a proxy for instances of this class
-	 * for COM Interop. set this flag on loading so all we need is a quick check
-	 * during object creation rather than having to traverse supertypes
-	 */
-	guint is_com_object : 1;
+
 	guint nested_classes_inited : 1; /* Whenever nested_class is initialized */
 
 	/* next byte*/