4 files changed, 27 insertions, 21 deletions

diff --git a/src/widgets/accessible/qaccessiblewidget.cpp b/src/widgets/accessible/qaccessiblewidget.cpp
index 3d18117dd78..b4adae2e6e6 100644
--- a/src/widgets/accessible/qaccessiblewidget.cpp
+++ b/src/widgets/accessible/qaccessiblewidget.cpp
@@ -224,29 +224,20 @@ QAccessibleWidget::relations(QAccessible::Relation match /*= QAccessible::AllRel
     QList<std::pair<QAccessibleInterface *, QAccessible::Relation>> rels;
     if (match & QAccessible::Label) {
         const QAccessible::Relation rel = QAccessible::Label;
-        if (QWidget *parent = widget()->parentWidget()) {
 #if QT_CONFIG(shortcut) && QT_CONFIG(label)
-            // first check for all siblings that are labels to us
-            // ideally we would go through all objects and check, but that
-            // will be too expensive
-            const QList<QWidget*> kids = _q_ac_childWidgets(parent);
-            for (QWidget *kid : kids) {
-                if (QLabel *labelSibling = qobject_cast<QLabel*>(kid)) {
-                    if (labelSibling->buddy() == widget()) {
-                        QAccessibleInterface *iface = QAccessible::queryAccessibleInterface(labelSibling);
-                        rels.emplace_back(iface, rel);
-                    }
-                }
-            }
+        for (QLabel *label : std::as_const(widget()->d_func()->labels)) {
+            Q_ASSERT(label);
+            QAccessibleInterface *iface = QAccessible::queryAccessibleInterface(label);
+            rels.emplace_back(iface, rel);
+        }
 #endif
 #if QT_CONFIG(groupbox)
-            QGroupBox *groupbox = qobject_cast<QGroupBox*>(parent);
-            if (groupbox && !groupbox->title().isEmpty()) {
-                QAccessibleInterface *iface = QAccessible::queryAccessibleInterface(groupbox);
-                rels.emplace_back(iface, rel);
-            }
-#endif
+        QGroupBox *groupbox = qobject_cast<QGroupBox *>(widget()->parentWidget());
+        if (groupbox && !groupbox->title().isEmpty()) {
+            QAccessibleInterface *iface = QAccessible::queryAccessibleInterface(groupbox);
+            rels.emplace_back(iface, rel);
         }
+#endif
     }
 
     if (match & QAccessible::Controlled) {
diff --git a/src/widgets/kernel/qwidget.h b/src/widgets/kernel/qwidget.h
index 02f328d2956..96565957a00 100644
--- a/src/widgets/kernel/qwidget.h
+++ b/src/widgets/kernel/qwidget.h
@@ -746,6 +746,7 @@ private:
     friend class QGuiApplication;
     friend class QGuiApplicationPrivate;
     friend class QBaseApplication;
+    friend class QLabel;
     friend class QPainter;
     friend class QPainterPrivate;
     friend class QPixmap; // for QPixmap::fill()
diff --git a/src/widgets/kernel/qwidget_p.h b/src/widgets/kernel/qwidget_p.h
index 991b932ecb8..ac417178813 100644
--- a/src/widgets/kernel/qwidget_p.h
+++ b/src/widgets/kernel/qwidget_p.h
@@ -19,6 +19,9 @@
 
 #include <QtWidgets/private/qtwidgetsglobal_p.h>
 #include "QtWidgets/qwidget.h"
+#if QT_CONFIG(label)
+#include <QtWidgets/qlabel.h>
+#endif
 #include "private/qobject_p.h"
 #include "QtCore/qrect.h"
 #include "QtCore/qlocale.h"
@@ -655,6 +658,10 @@ public:
     QPaintEngine *extraPaintEngine;
     mutable const QMetaObject *polished;
     QGraphicsEffect *graphicsEffect;
+#if QT_CONFIG(label)
+    // labels for which this widget is the buddy widget
+    QVarLengthArray<QLabel *, 1> labels;
+#endif
     // All widgets are added into the allWidgets set. Once
     // they receive a window id they are also added to the mapper.
     // This should just ensure that all widgets are deleted by QApplication
diff --git a/src/widgets/widgets/qlabel.cpp b/src/widgets/widgets/qlabel.cpp
index 72f299792bb..5cff4485fe3 100644
--- a/src/widgets/widgets/qlabel.cpp
+++ b/src/widgets/widgets/qlabel.cpp
@@ -187,6 +187,9 @@ QLabel::QLabel(const QString &text, QWidget *parent, Qt::WindowFlags f)
 QLabel::~QLabel()
 {
     Q_D(QLabel);
+
+    if (d->buddy)
+        d->buddy->d_func()->labels.removeAll(this);
     d->clearContents();
 }
 
@@ -1139,15 +1142,19 @@ void QLabel::setBuddy(QWidget *buddy)
 {
     Q_D(QLabel);
 
-    if (d->buddy)
+    if (d->buddy) {
         QObjectPrivate::disconnect(d->buddy, &QObject::destroyed,
                                    d, &QLabelPrivate::buddyDeleted);
+        d->buddy->d_func()->labels.removeAll(this);
+    }
 
     d->buddy = buddy;
 
-    if (buddy)
+    if (buddy) {
+        buddy->d_func()->labels.append(this);
         QObjectPrivate::connect(buddy, &QObject::destroyed,
                                 d, &QLabelPrivate::buddyDeleted);
+    }
 
     if (d->isTextLabel) {
         if (d->shortcutId)