Add a size field to the method list.

category.h

@@ -50,11 +50,11 @@ struct objc_category_legacy
 	/**
 	 * The list of instance methods to add to the class.
 	 */
-	struct objc_method_list   *instance_methods;
+	struct objc_method_list_legacy   *instance_methods;
 	/**
 	 * The list of class methods to add to the class.
 	 */
-	struct objc_method_list   *class_methods;
+	struct objc_method_list_legacy   *class_methods;
 	/**
 	 * The list of protocols adopted by this category.
 	 */

class.h

@@ -180,7 +180,7 @@ struct legacy_gnustep_objc_class
 	 * Metadata for for defining the mappings from selectors to IMPs.  Linked
 	 * list of method list structures, one per class and one per category.
 	 */
-	struct objc_method_list   *methods;
+	struct objc_method_list_legacy   *methods;
 	/**
 	 * The dispatch table for this class.  Intialized and maintained by the
 	 * runtime.

legacy.c

@@ -65,6 +65,23 @@ static struct objc_ivar_list *upgradeIvarList(struct legacy_gnustep_objc_class *
 	return n;
 }
 
+static struct objc_method_list *upgradeMethodList(struct objc_method_list_legacy *old)
+{
+	if (old == NULL)
+	{
+		return NULL;
+	}
+	struct objc_method_list *l = calloc(sizeof(struct objc_method_list) + old->count * sizeof(struct objc_method), 1);
+	l->count = old->count;
+	if (old->next)
+	{
+		l->next = upgradeMethodList(old->next);
+	}
+	l->size = sizeof(struct objc_method);
+	memcpy(&l->methods, &old->methods, old->count * sizeof(struct objc_method));
+	return l;
+}
+
 static int legacy_key;
 
 PRIVATE struct legacy_gnustep_objc_class* objc_legacy_class_for_class(Class cls)
@@ -82,7 +99,7 @@ PRIVATE Class objc_upgrade_class(struct legacy_gnustep_objc_class *oldClass)
 	cls->info = oldClass->info;
 	cls->instance_size = oldClass->instance_size;
 	cls->ivars = upgradeIvarList(oldClass);
-	cls->methods = oldClass->methods;
+	cls->methods = upgradeMethodList(oldClass->methods);
 	cls->protocols = oldClass->protocols;
 	cls->abi_version = oldClass->abi_version;
 	cls->properties = oldClass->properties;
@@ -99,5 +116,7 @@ PRIVATE struct objc_category *objc_upgrade_category(struct objc_category_legacy
 {
 	struct objc_category *cat = calloc(1, sizeof(struct objc_category));
 	memcpy(cat, old, sizeof(struct objc_category_legacy));
+	cat->instance_methods = upgradeMethodList(old->instance_methods);
+	cat->class_methods = upgradeMethodList(old->class_methods);
 	return cat;
 }

method_list.h

@@ -36,6 +36,30 @@ struct objc_method_list
 	 * The number of methods in this list.
 	 */
 	int                       count;
+	/**
+	 * Sze of `struct objc_method`.  This allows runtimes downgrading newer
+	 * versions of this structure.
+	 */
+	size_t                    size;
+	/**
+	 * An array of methods.  Note that the actual size of this is count.
+	 */
+	struct objc_method        methods[];
+};
+
+/**
+ * Legacy version of the method list.
+ */
+struct objc_method_list_legacy
+{
+	/**
+	 * The next group of methods in the list.
+	 */
+	struct objc_method_list_legacy *next;
+	/**
+	 * The number of methods in this list.
+	 */
+	int                       count;
 	/**
 	 * An array of methods.  Note that the actual size of this is count.
 	 */