Don't use mono_gc_is_moving for incremental gc

mono/metadata/boehm-gc.c

@@ -1576,9 +1576,15 @@ mono_gc_set_desktop_mode (void)
 
 gboolean
 mono_gc_is_moving (void)
+{
+	return FALSE;
+}
+
+gboolean 
+mono_gc_needs_write_barriers(void)
 {
 #if HAVE_BDWGC_GC
-	return GC_is_incremental_mode ();
+    return GC_is_incremental_mode();
 #else
 	return FALSE;
 #endif		

mono/metadata/domain.c

@@ -1252,12 +1252,10 @@ mono_domain_free (MonoDomain *domain, gboolean force)
 
 	domain->setup = NULL;
 
-#if !HAVE_BDWGC_GC
 	// This crashes in bdwgc because we never register such a root.
 	// Not sure why/how it works in sgen, or if it is needed?
 	if (mono_gc_is_moving ())
 		mono_gc_deregister_root ((char*)&(domain->MONO_DOMAIN_FIRST_GC_TRACKED));
-#endif
 
 	mono_appdomains_lock ();
 	appdomains_list [domain->domain_id] = NULL;

mono/metadata/gc-internals.h

@@ -54,7 +54,7 @@
 } while (0)
 
 /* useful until we keep track of gc-references in corlib etc. */
-#define IS_GC_REFERENCE(class,t) (mono_gc_is_moving () ? FALSE : ((t)->type == MONO_TYPE_U && (class)->image == mono_defaults.corlib))
+#define IS_GC_REFERENCE(class,t) (mono_gc_needs_write_barriers() ? FALSE : ((t)->type == MONO_TYPE_U && (class)->image == mono_defaults.corlib))
 
 void   mono_object_register_finalizer               (MonoObject  *obj);
 void   ves_icall_System_GC_InternalCollect          (int          generation);
@@ -280,6 +280,11 @@ void mono_gc_set_desktop_mode (void);
  */
 gboolean mono_gc_is_moving (void);
 
+/*
+ * Return whenever this GC needs write barriers
+ */
+gboolean mono_gc_needs_write_barriers (void);
+
 typedef void* (*MonoGCLockedCallbackFunc) (void *data);
 
 void* mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data);

mono/metadata/null-gc.c

@@ -430,6 +430,12 @@ mono_gc_is_moving (void)
 	return FALSE;
 }
 
+gboolean
+mono_gc_needs_write_barriers(void)
+{
+	return FALSE;
+}
+
 gboolean
 mono_gc_is_disabled (void)
 {

mono/metadata/object.c

@@ -5703,7 +5703,7 @@ mono_array_full_copy (MonoArray *src, MonoArray *dest)
 static void
 array_full_copy_unchecked_size (MonoArray *src, MonoArray *dest, MonoClass *klass, uintptr_t size)
 {
-	if (mono_gc_is_moving ()) {
+	if (mono_gc_needs_write_barriers()) {
 		if (klass->element_class->valuetype) {
 			if (klass->element_class->has_references)
 				mono_value_copy_array (dest, 0, mono_array_addr_with_size_fast (src, 0, 0), mono_array_length (src));
@@ -6447,7 +6447,7 @@ mono_value_box_checked (MonoDomain *domain, MonoClass *klass, gpointer value, Mo
 
 	size = size - sizeof (MonoObject);
 
-	if (mono_gc_is_moving ()) {
+	if (mono_gc_needs_write_barriers()) {
 		g_assert (size == mono_class_value_size (klass, NULL));
 		mono_gc_wbarrier_value_copy ((char *)res + sizeof (MonoObject), value, 1, klass);
 	} else {

mono/metadata/sgen-mono.c

@@ -2782,6 +2782,12 @@ mono_gc_is_moving (void)
 	return TRUE;
 }
 
+gboolean
+mono_gc_needs_write_barriers(void)
+{
+	return TRUE;
+}
+
 gboolean
 mono_gc_is_disabled (void)
 {

mono/metadata/threads.c

@@ -566,12 +566,10 @@ create_internal_thread_object (void)
 	 * Boehm incremental is not actually "moving", it does not need the thread_pinning_ref.
 	 * But having it causes problems when unregistering the root after domain reload.
 	 */
-#if !defined(HAVE_BOEHM_GC) 
 	if (mono_gc_is_moving ()) {
 		thread->thread_pinning_ref = thread;
 		MONO_GC_REGISTER_ROOT_PINNING (thread->thread_pinning_ref, MONO_ROOT_SOURCE_THREADING, NULL, "Thread Pinning Reference");
 	}
-#endif	
 
 	thread->priority = MONO_THREAD_PRIORITY_NORMAL;
 
@@ -894,12 +892,10 @@ mono_thread_detach_internal (MonoInternalThread *thread)
 	 * Boehm incremental is not actually "moving", it does not need the thread_pinning_ref.
 	 * But having it causes problems when unregistering the root after domain reload.
 	 */
-#if !defined(HAVE_BOEHM_GC)
 	if (mono_gc_is_moving ()) {
 		MONO_GC_UNREGISTER_ROOT (thread->thread_pinning_ref);
 		thread->thread_pinning_ref = NULL;
 	}
-#endif	
 
 done:
 	SET_CURRENT_OBJECT (NULL);

mono/mini/aot-compiler.c

@@ -4111,7 +4111,7 @@ add_wrappers (MonoAotCompile *acfg)
 		}
 
 		/* write barriers */
-		if (mono_gc_is_moving ()) {
+		if (mono_gc_needs_write_barriers()) {
 			add_method (acfg, mono_gc_get_specific_write_barrier (FALSE));
 			add_method (acfg, mono_gc_get_specific_write_barrier (TRUE));
 		}

mono/mini/mini-gc.c

@@ -2627,7 +2627,7 @@ mini_gc_set_slot_type_from_cfa (MonoCompile *cfg, int slot_offset, GCSlotType ty
 void
 mini_gc_init_cfg (MonoCompile *cfg)
 {
-	if (mono_gc_is_moving ()) {
+	if (mono_gc_needs_write_barriers()) {
 		cfg->disable_ref_noref_stack_slot_share = TRUE;
 		cfg->gen_write_barriers = TRUE;
 	}