diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9041e03..245e9ab 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -136,7 +136,7 @@ set(INCLUDE_DIRECTORY "objc" CACHE STRING
 if (${CMAKE_C_COMPILER_ID} MATCHES Clang*)
 	set(CMAKE_OBJC_FLAGS "${CMAKE_OBJC_FLAGS} -Wno-deprecated-objc-isa-usage -Wno-objc-root-class")
 	if (${CMAKE_C_COMPILER_VERSION} VERSION_GREATER 3.1)
-		set(CMAKE_OBJC_FLAGS "${CMAKE_OBJC_FLAGS} -fobjc-runtime=gnustep-1.7")
+		set(CMAKE_OBJC_FLAGS "${CMAKE_OBJC_FLAGS} -fobjc-runtime=gnustep-2.0")
 	endif ()
 else (${CMAKE_C_COMPILER_ID} MATCHES Clang*)
 	MESSAGE("WARNING: It is strongly recommended that you compile with clang")
diff --git a/Test/CMakeLists.txt b/Test/CMakeLists.txt
index 6425136..8277063 100644
--- a/Test/CMakeLists.txt
+++ b/Test/CMakeLists.txt
@@ -47,7 +47,7 @@ function(addtest_flags TEST_NAME FLAGS TEST_SOURCE)
 	set(ARC "")
 	set_target_properties(${TEST_NAME} PROPERTIES
 		INCLUDE_DIRECTORIES "${CMAKE_SOURCE_DIR}"
-		COMPILE_FLAGS "-fobjc-runtime=gnustep-1.7 -fblocks ${FLAGS}"
+		COMPILE_FLAGS "-fblocks ${FLAGS}"
 		LINKER_LANGUAGE C
 	)
 	set_property(TEST ${TEST_NAME} PROPERTY
@@ -58,8 +58,10 @@ endfunction(addtest_flags)
 
 foreach(TEST_SOURCE ${TESTS})
 	get_filename_component(TEST ${TEST_SOURCE} NAME_WE)
-	addtest_flags(${TEST} "-O0" ${TEST_SOURCE})
-	addtest_flags("${TEST}_optimised" "-O3" ${TEST_SOURCE})
+	addtest_flags(${TEST} "-O0 -fobjc-runtime=gnustep-2.0" ${TEST_SOURCE})
+	addtest_flags("${TEST}_optimised" "-O3 -fobjc-runtime=gnustep-2.0" ${TEST_SOURCE})
+	addtest_flags("${TEST}_legacy" "-O0 -fobjc-runtime=gnustep-1.7" ${TEST_SOURCE})
+	addtest_flags("${TEST}_legacy_optimised" "-O3 -fobjc-runtime=gnustep-1.7" ${TEST_SOURCE})
 endforeach()
 
 # Tests that are more than a single file.
diff --git a/loader.c b/loader.c
index 70ab229..d0a2f54 100644
--- a/loader.c
+++ b/loader.c
@@ -43,15 +43,9 @@ __attribute__((weak)) void (*dispatch_end_thread_4GC)(void);
 __attribute__((weak)) void *(*_dispatch_begin_NSAutoReleasePool)(void);
 __attribute__((weak)) void (*_dispatch_end_NSAutoReleasePool)(void *);
 
-void __objc_exec_class(struct objc_module_abi_8 *module)
+static void init_runtime(void)
 {
 	static BOOL first_run = YES;
-
-	// Check that this module uses an ABI version that we recognise.  
-	// In future, we should pass the ABI version to the class / category load
-	// functions so that we can change various structures more easily.
-	assert(objc_check_abi_version(module));
-
 	if (first_run)
 	{
 #if ENABLE_GC
@@ -94,6 +88,117 @@ void __objc_exec_class(struct objc_module_abi_8 *module)
 			_dispatch_end_NSAutoReleasePool = objc_autoreleasePoolPop;
 		}
 	}
+}
+
+struct objc_init
+{
+	uint64_t version;
+	SEL sel_begin;
+	SEL sel_end;
+	Class *cls_begin;
+	Class *cls_end;
+	char **cls_ref_begin;
+	char **cls_ref_end;
+	struct objc_category *cat_begin;
+	struct objc_category *cat_end;
+	struct objc_protocol2 *proto_begin;
+	struct objc_protocol2 *proto_end;
+};
+#include <dlfcn.h>
+
+void registerProtocol(Protocol *proto);
+
+void __objc_load(struct objc_init *init)
+{
+	init_runtime();
+#ifdef DEBUG_LOADING
+	Dl_info info;
+	if (dladdr(init, &info))
+	{
+		fprintf(stderr, "Loading %p from object: %s (%p)\n", init, info.dli_fname, __builtin_return_address(0));
+	}
+	else
+	{
+		fprintf(stderr, "Loading %p from unknown object\n", init);
+	}
+#endif
+	LOCK_RUNTIME_FOR_SCOPE();
+	assert(init->version == 0);
+	assert((((uintptr_t)init->sel_end-(uintptr_t)init->sel_begin) % sizeof(*init->sel_begin)) == 0);
+	assert((((uintptr_t)init->cls_end-(uintptr_t)init->cls_begin) % sizeof(*init->cls_begin)) == 0);
+	assert((((uintptr_t)init->cat_end-(uintptr_t)init->cat_begin) % sizeof(*init->cat_begin)) == 0);
+	for (SEL sel = init->sel_begin ; sel < init->sel_end ; sel++)
+	{
+		if (sel->name == 0)
+		{
+			continue;
+		}
+		objc_register_selector(sel);
+	}
+	int i = 0;
+	for (struct objc_protocol2 *proto = init->proto_begin ; proto < init->proto_end ;
+	     proto++)
+	{
+		if (proto->name == NULL)
+		{
+			continue;
+		}
+		registerProtocol((struct objc_protocol*)proto);
+	}
+	for (Class *cls = init->cls_begin ; cls < init->cls_end ; cls++)
+	{
+		if (*cls == NULL)
+		{
+			continue;
+		}
+		objc_load_class(*cls);
+	}
+	for (char **cls = init->cls_ref_begin ; cls < init->cls_ref_end ; cls++)
+	{
+		id *out = (id*)cls;
+		if (*out == nil)
+		{
+			continue;
+		}
+		*out = objc_getClass(*cls);
+		assert(*out);
+	}
+	for (struct objc_category *cat = init->cat_begin ; cat < init->cat_end ;
+	     cat++)
+	{
+		if (cat == NULL)
+		{
+			continue;
+		}
+		objc_try_load_category(cat);
+	}
+	// Load categories and statics that were deferred.
+	objc_load_buffered_categories();
+	// Fix up the class links for loaded classes.
+	objc_resolve_class_links();
+	for (struct objc_category *cat = init->cat_begin ; cat < init->cat_end ;
+	     cat++)
+	{
+		Class class = (Class)objc_getClass(cat->class_name);
+		if ((Nil != class) && 
+		    objc_test_class_flag(class, objc_class_flag_resolved))
+		{
+			objc_send_load_message(class);
+		}
+	}
+	init->version = 0xffffffffffffffffULL;
+}
+
+void __objc_exec_class(struct objc_module_abi_8 *module)
+{
+	init_runtime();
+
+	// Check that this module uses an ABI version that we recognise.  
+	// In future, we should pass the ABI version to the class / category load
+	// functions so that we can change various structures more easily.
+	assert(objc_check_abi_version(module));
+	fprintf(stderr, "Loading %s\n", module->name);
+
 
 	// The runtime mutex is held for the entire duration of a load.  It does
 	// not need to be acquired or released in any of the called load functions.
diff --git a/protocol.c b/protocol.c
index 4a58e96..9c11e46 100644
--- a/protocol.c
+++ b/protocol.c
@@ -521,6 +521,11 @@ void objc_registerProtocol(Protocol *proto)
 	proto->isa = ObjC2ProtocolClass;
 	protocol_table_insert((struct objc_protocol2*)proto);
 }
+PRIVATE void registerProtocol(Protocol *proto)
+{
+	LOCK_RUNTIME_FOR_SCOPE();
+	protocol_table_insert((struct objc_protocol2*)proto);
+}
 void protocol_addMethodDescription(Protocol *aProtocol,
                                    SEL name,
                                    const char *types,