qom: Propagate alignment through type system

Propagate alignment just like size.  This is required in order to
get the correct alignment on most cpu subclasses where the size and
alignment is only specified for the base cpu type.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

qom/object.c

@@ -220,6 +220,19 @@ static size_t type_object_get_size(TypeImpl *ti)
     return 0;
 }
 
+static size_t type_object_get_align(TypeImpl *ti)
+{
+    if (ti->instance_align) {
+        return ti->instance_align;
+    }
+
+    if (type_has_parent(ti)) {
+        return type_object_get_align(type_get_parent(ti));
+    }
+
+    return 0;
+}
+
 size_t object_type_get_instance_size(const char *typename)
 {
     TypeImpl *type = type_get_by_name(typename);
@@ -293,6 +306,7 @@ static void type_initialize(TypeImpl *ti)
 
     ti->class_size = type_class_get_size(ti);
     ti->instance_size = type_object_get_size(ti);
+    ti->instance_align = type_object_get_align(ti);
     /* Any type with zero instance_size is implicitly abstract.
      * This means interface types are all abstract.
      */