From 818de32db28375dbe5d8bd93121fe751720911f2 Mon Sep 17 00:00:00 2001
From: Simon Hausmann <simon.hausmann@qt.io>
Date: Thu, 16 Apr 2020 10:02:58 +0200
Subject: [PATCH] Attempt to squeeze unionized fake qproperty members even
 further

... by using the [[no_unique_address]] attribute, if available, instead
of the union.

Change-Id: Iab4db7039f1140a0005c7dd2fb6e08597ceec8f5
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
---
 src/corelib/kernel/qtmetamacros.h | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/corelib/kernel/qtmetamacros.h b/src/corelib/kernel/qtmetamacros.h
index fb89722847..432fd8a49b 100644
--- a/src/corelib/kernel/qtmetamacros.h
+++ b/src/corelib/kernel/qtmetamacros.h
@@ -115,10 +115,17 @@ QT_BEGIN_NAMESPACE
                 QPropertyBinding<type> takeBinding(); \
             }; \
             void setter(const type &value);
+#if __has_cpp_attribute(no_unique_address)
+#define Q_PRIVATE_QPROPERTIES_BEGIN
+#define QT_PRIVATE_QPROPERTY_PREFIX [[no_unique_address]]
+#define Q_PRIVATE_QPROPERTIES_END
+#else
 #define Q_PRIVATE_QPROPERTIES_BEGIN union {
-#define Q_PRIVATE_QPROPERTY_IMPL(name) \
-            _qt_property_api_##name name;
+#define QT_PRIVATE_QPROPERTY_PREFIX
 #define Q_PRIVATE_QPROPERTIES_END };
+#endif
+#define Q_PRIVATE_QPROPERTY_IMPL(name) \
+        QT_PRIVATE_QPROPERTY_PREFIX _qt_property_api_##name name;
 #ifndef Q_REVISION
 # define Q_REVISION(...)
 #endif