Don't use mono_gc_is_moving for incremental gc (#1228)

Author: jechter

mono/metadata/boehm-gc.c

@@ -237,17 +237,16 @@ mono_gc_base_init (void)
 				opt = strchr (opt, '=') + 1;
 				if (*opt && mono_gc_parse_environment_string_extract_number (opt, &time_limit)) {
 					GC_enable_incremental ();
-			#if HAVE_BDWGC_GC	
-					if (time_limit != 0)
+					if (time_limit != 0) {
 						// value is in milliseconds
 						GC_set_time_limit (time_limit);
-			#endif					
+					}
 				}
 				continue;
 			} else if (g_str_has_prefix (opt, "strict-wbarriers")) {
 				gc_strict_wbarriers = TRUE;
 				continue;
-			}else {
+			} else {
 				/* Could be a parameter for sgen */
 				/*
 				fprintf (stderr, "MONO_GC_PARAMS must be a comma-delimited list of one or more of the following:\n");
@@ -1174,6 +1173,12 @@ mono_gc_set_desktop_mode (void)
 
 gboolean
 mono_gc_is_moving (void)
+{
+	return FALSE;
+}
+
+gboolean 
+mono_gc_needs_write_barriers(void)
 {
 	return GC_is_incremental_mode ();
 }

mono/metadata/gc-internals.h

@@ -62,7 +62,7 @@
 } 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);
 
@@ -320,6 +320,11 @@ 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

@@ -454,6 +454,12 @@ 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

@@ -6304,7 +6304,7 @@ 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 ()) {
 		MonoClass *element_class = m_class_get_element_class (klass);
 		if (m_class_is_valuetype (element_class)) {
 			if (m_class_has_references (element_class))
@@ -7170,7 +7170,7 @@ mono_value_box_handle (MonoDomain *domain, MonoClass *klass, gpointer value, Mon
 	return_val_if_nok (error, NULL_HANDLE);
 
 	size -= MONO_ABI_SIZEOF (MonoObject);
-	if (mono_gc_is_moving ()) {
+	if (mono_gc_needs_write_barriers ()) {
 		g_assert (size == mono_class_value_size (klass, NULL));
 		MONO_ENTER_NO_SAFEPOINTS;
 		gpointer data = mono_handle_get_data_unsafe (res_handle);

mono/metadata/sgen-mono.c

@@ -2558,6 +2558,12 @@ mono_gc_is_moving (void)
 	return TRUE;
 }
 
+gboolean
+mono_gc_needs_write_barriers(void)
+{
+	return TRUE;
+}
+
 gboolean
 mono_gc_is_disabled (void)
 {

mono/mini/aot-compiler.c

@@ -4412,7 +4412,7 @@ add_gc_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

@@ -2647,7 +2647,7 @@ 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;
 	}