Merge remote-tracking branch 'origin/dev' into wip/scenegraphng

Change-Id: Ie2b9472ba925df6e6a74727d44d8179557072105

22 files changed, 486 insertions, 451 deletions

diff --git a/src/qml/qml/ftw/ftw.pri b/src/qml/qml/ftw/ftw.pri
index 0bb8cb954e..eadba394b4 100644
--- a/src/qml/qml/ftw/ftw.pri
+++ b/src/qml/qml/ftw/ftw.pri
@@ -3,6 +3,7 @@ HEADERS +=  \
     $$PWD/qintrusivelist_p.h \
     $$PWD/qpodvector_p.h \
     $$PWD/qhashedstring_p.h \
+    $$PWD/qprimefornumbits_p.h \
     $$PWD/qqmlrefcount_p.h \
     $$PWD/qfieldlist_p.h \
     $$PWD/qqmlthread_p.h \
@@ -18,8 +19,7 @@ HEADERS +=  \
 SOURCES += \
     $$PWD/qintrusivelist.cpp \
     $$PWD/qhashedstring.cpp \
-    $$PWD/qqmlthread.cpp \
-    $$PWD/qstringhash.cpp
+    $$PWD/qqmlthread.cpp
 
 # mirrors logic in $$QT_SOURCE_TREE/config.tests/unix/clock-gettime/clock-gettime.pri
 # clock_gettime() is implemented in librt on these systems
diff --git a/src/qml/qml/ftw/qhashedstring.cpp b/src/qml/qml/ftw/qhashedstring.cpp
index bb6688599d..7a8fdd0a14 100644
--- a/src/qml/qml/ftw/qhashedstring.cpp
+++ b/src/qml/qml/ftw/qhashedstring.cpp
@@ -41,6 +41,60 @@
 
 QT_BEGIN_NAMESPACE
 
+// Copy of QString's qMemCompare
+bool QHashedString::compare(const QChar *lhs, const QChar *rhs, int length)
+{
+    Q_ASSERT(lhs && rhs);
+    const quint16 *a = (const quint16 *)lhs;
+    const quint16 *b = (const quint16 *)rhs;
+
+    if (a == b || !length)
+        return true;
+
+    union {
+        const quint16 *w;
+        const quint32 *d;
+        quintptr value;
+    } sa, sb;
+    sa.w = a;
+    sb.w = b;
+
+    // check alignment
+    if ((sa.value & 2) == (sb.value & 2)) {
+        // both addresses have the same alignment
+        if (sa.value & 2) {
+            // both addresses are not aligned to 4-bytes boundaries
+            // compare the first character
+            if (*sa.w != *sb.w)
+                return false;
+            --length;
+            ++sa.w;
+            ++sb.w;
+
+            // now both addresses are 4-bytes aligned
+        }
+
+        // both addresses are 4-bytes aligned
+        // do a fast 32-bit comparison
+        const quint32 *e = sa.d + (length >> 1);
+        for ( ; sa.d != e; ++sa.d, ++sb.d) {
+            if (*sa.d != *sb.d)
+                return false;
+        }
+
+        // do we have a tail?
+        return (length & 1) ? *sa.w == *sb.w : true;
+    } else {
+        // one of the addresses isn't 4-byte aligned but the other is
+        const quint16 *e = sa.w + length;
+        for ( ; sa.w != e; ++sa.w, ++sb.w) {
+            if (*sa.w != *sb.w)
+                return false;
+        }
+    }
+    return true;
+}
+
 QHashedStringRef QHashedStringRef::mid(int offset, int length) const
 {
     Q_ASSERT(offset < m_length);
diff --git a/src/qml/qml/ftw/qprimefornumbits_p.h b/src/qml/qml/ftw/qprimefornumbits_p.h
new file mode 100644
index 0000000000..6e9acbf7fd
--- /dev/null
+++ b/src/qml/qml/ftw/qprimefornumbits_p.h
@@ -0,0 +1,80 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtQml module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QPRIMEFORNUMBITS_P_H
+#define QPRIMEFORNUMBITS_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <private/qtqmlglobal_p.h>
+
+QT_BEGIN_NAMESPACE
+
+/*
+    The prime_deltas array is a table of selected prime values, even
+    though it doesn't look like one. The primes we are using are 1,
+    2, 5, 11, 17, 37, 67, 131, 257, ..., i.e. primes in the immediate
+    surrounding of a power of two.
+
+    The qPrimeForNumBits() function returns the prime associated to a
+    power of two. For example, qPrimeForNumBits(8) returns 257.
+*/
+
+inline int qPrimeForNumBits(int numBits)
+{
+    static constexpr const uchar prime_deltas[] = {
+        0,  0,  1,  3,  1,  5,  3,  3,  1,  9,  7,  5,  3,  9, 25,  3,
+        1, 21,  3, 21,  7, 15,  9,  5,  3, 29, 15,  0,  0,  0,  0,  0
+    };
+
+    return (1 << numBits) + prime_deltas[numBits];
+}
+
+QT_END_NAMESPACE
+
+#endif // QPRIMEFORNUMBITS_P_H
diff --git a/src/qml/qml/ftw/qstringhash.cpp b/src/qml/qml/ftw/qstringhash.cpp
deleted file mode 100644
index a483dcb810..0000000000
--- a/src/qml/qml/ftw/qstringhash.cpp
+++ /dev/null
@@ -1,168 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2019 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the QtQml module of the Qt Toolkit.
-**
-** $QT_BEGIN_LICENSE:LGPL$
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU Lesser General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU Lesser
-** General Public License version 3 as published by the Free Software
-** Foundation and appearing in the file LICENSE.LGPL3 included in the
-** packaging of this file. Please review the following information to
-** ensure the GNU Lesser General Public License version 3 requirements
-** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 2.0 or (at your option) the GNU General
-** Public license version 3 or any later version approved by the KDE Free
-** Qt Foundation. The licenses are as published by the Free Software
-** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-2.0.html and
-** https://www.gnu.org/licenses/gpl-3.0.html.
-**
-** $QT_END_LICENSE$
-**
-****************************************************************************/
-
-#include "qstringhash_p.h"
-
-QT_BEGIN_NAMESPACE
-
-/*
-    A QHash has initially around pow(2, MinNumBits) buckets. For
-    example, if MinNumBits is 4, it has 17 buckets.
-*/
-static const int MinNumBits = 4;
-
-/*
-    The prime_deltas array is a table of selected prime values, even
-    though it doesn't look like one. The primes we are using are 1,
-    2, 5, 11, 17, 37, 67, 131, 257, ..., i.e. primes in the immediate
-    surrounding of a power of two.
-
-    The primeForNumBits() function returns the prime associated to a
-    power of two. For example, primeForNumBits(8) returns 257.
-*/
-
-static const uchar prime_deltas[] = {
-    0,  0,  1,  3,  1,  5,  3,  3,  1,  9,  7,  5,  3,  9, 25,  3,
-    1, 21,  3, 21,  7, 15,  9,  5,  3, 29, 15,  0,  0,  0,  0,  0
-};
-
-static inline int primeForNumBits(int numBits)
-{
-    return (1 << numBits) + prime_deltas[numBits];
-}
-
-void QStringHashData::rehashToSize(int size)
-{
-    short bits = qMax(MinNumBits, (int)numBits);
-    while (primeForNumBits(bits) < size) bits++;
-
-    if (bits > numBits)
-        rehashToBits(bits);
-}
-
-void QStringHashData::rehashToBits(short bits)
-{
-    numBits = qMax(MinNumBits, (int)bits);
-
-    int nb = primeForNumBits(numBits);
-    if (nb == numBuckets && buckets)
-        return;
-
-    QStringHashNode **newBuckets = new QStringHashNode *[nb];
-    ::memset(newBuckets, 0, sizeof(QStringHashNode *) * nb);
-
-    // Preserve the existing order within buckets so that items with the
-    // same key will retain the same find/findNext order
-    for (int i = 0; i < numBuckets; ++i) {
-        QStringHashNode *bucket = buckets[i];
-        if (bucket)
-            rehashNode(newBuckets, nb, bucket);
-    }
-
-    delete [] buckets;
-    buckets = newBuckets;
-    numBuckets = nb;
-}
-
-void QStringHashData::rehashNode(QStringHashNode **newBuckets, int nb, QStringHashNode *node)
-{
-    QStringHashNode *next = node->next.data();
-    if (next)
-        rehashNode(newBuckets, nb, next);
-
-    int bucket = node->hash % nb;
-    node->next = newBuckets[bucket];
-    newBuckets[bucket] = node;
-}
-
-// Copy of QString's qMemCompare
-bool QHashedString::compare(const QChar *lhs, const QChar *rhs, int length)
-{
-    Q_ASSERT(lhs && rhs);
-    const quint16 *a = (const quint16 *)lhs;
-    const quint16 *b = (const quint16 *)rhs;
-
-    if (a == b || !length)
-        return true;
-
-    union {
-        const quint16 *w;
-        const quint32 *d;
-        quintptr value;
-    } sa, sb;
-    sa.w = a;
-    sb.w = b;
-
-    // check alignment
-    if ((sa.value & 2) == (sb.value & 2)) {
-        // both addresses have the same alignment
-        if (sa.value & 2) {
-            // both addresses are not aligned to 4-bytes boundaries
-            // compare the first character
-            if (*sa.w != *sb.w)
-                return false;
-            --length;
-            ++sa.w;
-            ++sb.w;
-
-            // now both addresses are 4-bytes aligned
-        }
-
-        // both addresses are 4-bytes aligned
-        // do a fast 32-bit comparison
-        const quint32 *e = sa.d + (length >> 1);
-        for ( ; sa.d != e; ++sa.d, ++sb.d) {
-            if (*sa.d != *sb.d)
-                return false;
-        }
-
-        // do we have a tail?
-        return (length & 1) ? *sa.w == *sb.w : true;
-    } else {
-        // one of the addresses isn't 4-byte aligned but the other is
-        const quint16 *e = sa.w + length;
-        for ( ; sa.w != e; ++sa.w, ++sb.w) {
-            if (*sa.w != *sb.w)
-                return false;
-        }
-    }
-    return true;
-}
-
-QT_END_NAMESPACE
diff --git a/src/qml/qml/ftw/qstringhash_p.h b/src/qml/qml/ftw/qstringhash_p.h
index c7251e8837..f9435b4919 100644
--- a/src/qml/qml/ftw/qstringhash_p.h
+++ b/src/qml/qml/ftw/qstringhash_p.h
@@ -52,11 +52,14 @@
 //
 
 #include <private/qhashedstring_p.h>
+#include <private/qprimefornumbits_p.h>
+
+#include <QtCore/qglobal.h>
 
 QT_BEGIN_NAMESPACE
 
 class QStringHashData;
-class Q_AUTOTEST_EXPORT QStringHashNode
+class QStringHashNode
 {
 public:
     QStringHashNode()
@@ -154,12 +157,20 @@ public:
     }
 };
 
-class Q_AUTOTEST_EXPORT QStringHashData
+class QStringHashData
 {
+    Q_DISABLE_COPY_MOVE(QStringHashData)
 public:
-    QStringHashData() {}
+    QStringHashData() = default;
+    ~QStringHashData() = default;
+
+    /*
+        A QHash has initially around pow(2, MinNumBits) buckets. For
+        example, if MinNumBits is 4, it has 17 buckets.
+    */
+    enum { MinNumBits = 4 };
 
-    QStringHashNode **buckets = nullptr;
+    QStringHashNode **buckets = nullptr; // life cycle managed by QStringHash
     int numBuckets = 0;
     int size = 0;
     short numBits = 0;
@@ -174,13 +185,51 @@ public:
         QStringHashNode *n;
         StringHash *p;
     };
-    void rehashToBits(short);
-    void rehashToSize(int);
-    void rehashNode(QStringHashNode **newBuckets, int nb, QStringHashNode *node);
 
-private:
-    QStringHashData(const QStringHashData &);
-    QStringHashData &operator=(const QStringHashData &);
+    void rehashToBits(short bits)
+    {
+        numBits = qMax(short(MinNumBits), bits);
+
+        int nb = qPrimeForNumBits(numBits);
+        if (nb == numBuckets && buckets)
+            return;
+
+        QStringHashNode **newBuckets = new QStringHashNode *[nb];
+        ::memset(newBuckets, 0, sizeof(QStringHashNode *) * nb);
+
+        // Preserve the existing order within buckets so that items with the
+        // same key will retain the same find/findNext order
+        for (int i = 0; i < numBuckets; ++i) {
+            QStringHashNode *bucket = buckets[i];
+            if (bucket)
+                rehashNode(newBuckets, nb, bucket);
+        }
+
+        delete [] buckets;
+        buckets = newBuckets;
+        numBuckets = nb;
+    }
+
+    void rehashToSize(int size)
+    {
+        short bits = qMax(short(MinNumBits), numBits);
+        while (qPrimeForNumBits(bits) < size)
+            bits++;
+
+        if (bits > numBits)
+            rehashToBits(bits);
+    }
+
+    void rehashNode(QStringHashNode **newBuckets, int nb, QStringHashNode *node)
+    {
+        QStringHashNode *next = node->next.data();
+        if (next)
+            rehashNode(newBuckets, nb, next);
+
+        int bucket = node->hash % nb;
+        node->next = newBuckets[bucket];
+        newBuckets[bucket] = node;
+    }
 };
 
 // For a supplied key type, in what form do we need to keep a hashed version?
diff --git a/src/qml/qml/qqml.h b/src/qml/qml/qqml.h
index 3000f56601..7b3f89e943 100644
--- a/src/qml/qml/qqml.h
+++ b/src/qml/qml/qqml.h
@@ -579,9 +579,15 @@ namespace QtQml {
     Q_QML_EXPORT void qmlExecuteDeferred(QObject *);
     Q_QML_EXPORT QQmlContext *qmlContext(const QObject *);
     Q_QML_EXPORT QQmlEngine *qmlEngine(const QObject *);
-    Q_QML_EXPORT QObject *qmlAttachedPropertiesObjectById(int, const QObject *, bool create = true);
-    Q_QML_EXPORT QObject *qmlAttachedPropertiesObject(int *, const QObject *,
-                                                      const QMetaObject *, bool create);
+#if QT_DEPRECATED_SINCE(5, 14)
+    Q_QML_EXPORT QT_DEPRECATED QObject *qmlAttachedPropertiesObjectById(int, const QObject *, bool create = true);
+    Q_QML_EXPORT QT_DEPRECATED QObject *qmlAttachedPropertiesObject(
+            int *, const QObject *, const QMetaObject *, bool create);
+#endif
+    Q_QML_EXPORT QQmlAttachedPropertiesFunc qmlAttachedPropertiesFunction(QObject *,
+                                                                          const QMetaObject *);
+    Q_QML_EXPORT QObject *qmlAttachedPropertiesObject(QObject *, QQmlAttachedPropertiesFunc func,
+                                                      bool create = true);
 #ifndef Q_QDOC
 }
 
@@ -602,8 +608,9 @@ Q_QML_EXPORT void qmlRegisterModule(const char *uri, int versionMajor, int versi
 template<typename T>
 QObject *qmlAttachedPropertiesObject(const QObject *obj, bool create = true)
 {
-    static int idx = -1;
-    return qmlAttachedPropertiesObject(&idx, obj, &T::staticMetaObject, create);
+    QObject *mutableObj = const_cast<QObject *>(obj);
+    return qmlAttachedPropertiesObject(
+            mutableObj, qmlAttachedPropertiesFunction(mutableObj, &T::staticMetaObject), create);
 }
 
 inline int qmlRegisterSingletonType(const char *uri, int versionMajor, int versionMinor, const char *typeName,
diff --git a/src/qml/qml/qqmlbinding.cpp b/src/qml/qml/qqmlbinding.cpp
index b164517011..656c7dd515 100644
--- a/src/qml/qml/qqmlbinding.cpp
+++ b/src/qml/qml/qqmlbinding.cpp
@@ -517,9 +517,9 @@ QString QQmlBinding::expressionIdentifier() const
 {
     if (auto f = function()) {
         QString url = f->sourceFile();
-        quint16 lineNumber = f->compiledFunction->location.line;
-        quint16 columnNumber = f->compiledFunction->location.column;
-        return url + QString::asprintf(":%u:%u", uint(lineNumber), uint(columnNumber));
+        uint lineNumber = f->compiledFunction->location.line;
+        uint columnNumber = f->compiledFunction->location.column;
+        return url + QString::asprintf(":%u:%u", lineNumber, columnNumber);
     }
 
     return QStringLiteral("[native code]");
diff --git a/src/qml/qml/qqmldata_p.h b/src/qml/qml/qqmldata_p.h
index 2468de6857..f4c03fc17c 100644
--- a/src/qml/qml/qqmldata_p.h
+++ b/src/qml/qml/qqmldata_p.h
@@ -57,6 +57,7 @@
 #include <private/qv4value_p.h>
 #include <private/qv4persistent_p.h>
 #include <private/qqmlrefcount_p.h>
+#include <qqmlprivate.h>
 #include <qjsengine.h>
 #include <qvector.h>
 
@@ -265,7 +266,7 @@ public:
     }
 
     bool hasExtendedData() const { return extendedData != nullptr; }
-    QHash<int, QObject *> *attachedProperties() const;
+    QHash<QQmlAttachedPropertiesFunc, QObject *> *attachedProperties() const;
 
     static inline bool wasDeleted(const QObject *);
 
diff --git a/src/qml/qml/qqmlengine.cpp b/src/qml/qml/qqmlengine.cpp
index f070f16afd..bb2b3e462c 100644
--- a/src/qml/qml/qqmlengine.cpp
+++ b/src/qml/qml/qqmlengine.cpp
@@ -1057,7 +1057,7 @@ QQmlEngine::~QQmlEngine()
     // XXX TODO: performance -- store list of singleton types separately?
     QList<QQmlType> singletonTypes = QQmlMetaType::qmlSingletonTypes();
     for (const QQmlType &currType : singletonTypes)
-        currType.singletonInstanceInfo()->destroy(this);
+        d->destroySingletonInstance(currType);
 
     delete d->rootContext;
     d->rootContext = nullptr;
@@ -1402,23 +1402,13 @@ void QQmlEngine::setOutputWarningsToStandardError(bool enabled)
 template<>
 QJSValue QQmlEngine::singletonInstance<QJSValue>(int qmlTypeId)
 {
+    Q_D(QQmlEngine);
     QQmlType type = QQmlMetaType::qmlType(qmlTypeId, QQmlMetaType::TypeIdCategory::QmlType);
 
     if (!type.isValid() || !type.isSingleton())
         return QJSValue();
 
-    QQmlType::SingletonInstanceInfo* info = type.singletonInstanceInfo();
-    info->init(this);
-
-    if (QObject* o = info->qobjectApi(this))
-        return this->newQObject(o);
-    else {
-        QJSValue value = info->scriptApi(this);
-        if (!value.isUndefined())
-            return value;
-    }
-
-    return QJSValue();
+    return d->singletonInstance<QJSValue>(type);
 }
 
 /*!
@@ -1617,29 +1607,39 @@ QQmlEngine *qmlEngine(const QObject *obj)
     return data->context->engine;
 }
 
-QObject *qmlAttachedPropertiesObjectById(int id, const QObject *object, bool create)
+static QObject *resolveAttachedProperties(QQmlAttachedPropertiesFunc pf, QQmlData *data,
+                                          QObject *object, bool create)
 {
-    QQmlData *data = QQmlData::get(object, create);
-    if (!data)
-        return nullptr; // Attached properties are only on objects created by QML, unless explicitly requested (create==true)
+    if (!pf)
+        return nullptr;
 
-    QObject *rv = data->hasExtendedData()?data->attachedProperties()->value(id):0;
+    QObject *rv = data->hasExtendedData() ? data->attachedProperties()->value(pf) : 0;
     if (rv || !create)
         return rv;
 
-    QQmlEnginePrivate *engine = QQmlEnginePrivate::get(data->context);
-    QQmlAttachedPropertiesFunc pf = QQmlMetaType::attachedPropertiesFuncById(engine, id);
-    if (!pf)
-        return nullptr;
-
-    rv = pf(const_cast<QObject *>(object));
+    rv = pf(object);
 
     if (rv)
-        data->attachedProperties()->insert(id, rv);
+        data->attachedProperties()->insert(pf, rv);
 
     return rv;
 }
 
+#if QT_DEPRECATED_SINCE(5, 14)
+QObject *qmlAttachedPropertiesObjectById(int id, const QObject *object, bool create)
+{
+    QQmlData *data = QQmlData::get(object, create);
+
+    // Attached properties are only on objects created by QML,
+    // unless explicitly requested (create==true)
+    if (!data)
+        return nullptr;
+
+    QQmlEnginePrivate *engine = QQmlEnginePrivate::get(data->context);
+    return resolveAttachedProperties(QQmlMetaType::attachedPropertiesFuncById(engine, id), data,
+                                     const_cast<QObject *>(object), create);
+}
+
 QObject *qmlAttachedPropertiesObject(int *idCache, const QObject *object,
                                      const QMetaObject *attachedMetaObject, bool create)
 {
@@ -1653,6 +1653,30 @@ QObject *qmlAttachedPropertiesObject(int *idCache, const QObject *object,
 
     return qmlAttachedPropertiesObjectById(*idCache, object, create);
 }
+#endif
+
+QQmlAttachedPropertiesFunc qmlAttachedPropertiesFunction(QObject *object,
+                                                         const QMetaObject *attachedMetaObject)
+{
+    QQmlEngine *engine = object ? qmlEngine(object) : nullptr;
+    return QQmlMetaType::attachedPropertiesFunc(engine ? QQmlEnginePrivate::get(engine) : nullptr,
+                                                attachedMetaObject);
+}
+
+QObject *qmlAttachedPropertiesObject(QObject *object, QQmlAttachedPropertiesFunc func, bool create)
+{
+    if (!object)
+        return nullptr;
+
+    QQmlData *data = QQmlData::get(object, create);
+
+    // Attached properties are only on objects created by QML,
+    // unless explicitly requested (create==true)
+    if (!data)
+        return nullptr;
+
+    return resolveAttachedProperties(func, data, object, create);
+}
 
 } // namespace QtQml
 
@@ -1694,7 +1718,7 @@ public:
     QQmlDataExtended();
     ~QQmlDataExtended();
 
-    QHash<int, QObject *> attachedProperties;
+    QHash<QQmlAttachedPropertiesFunc, QObject *> attachedProperties;
 };
 
 QQmlDataExtended::QQmlDataExtended()
@@ -1840,7 +1864,7 @@ void QQmlData::disconnectNotifiers()
     }
 }
 
-QHash<int, QObject *> *QQmlData::attachedProperties() const
+QHash<QQmlAttachedPropertiesFunc, QObject *> *QQmlData::attachedProperties() const
 {
     if (!extendedData) extendedData = new QQmlDataExtended;
     return &extendedData->attachedProperties;
@@ -2413,6 +2437,67 @@ void QQmlEnginePrivate::unregisterInternalCompositeType(QV4::CompiledData::Compi
     m_compositeTypes.remove(compilationUnit->metaTypeId);
 }
 
+template<>
+QJSValue QQmlEnginePrivate::singletonInstance<QJSValue>(const QQmlType &type)
+{
+    Q_Q(QQmlEngine);
+
+    QJSValue value = singletonInstances.value(type);
+    if (!value.isUndefined()) {
+        return value;
+    }
+
+    QQmlType::SingletonInstanceInfo *siinfo = type.singletonInstanceInfo();
+    Q_ASSERT(siinfo != nullptr);
+
+    if (siinfo->scriptCallback) {
+        value = siinfo->scriptCallback(q, q);
+        if (value.isQObject()) {
+            QObject *o = value.toQObject();
+            // even though the object is defined in C++, qmlContext(obj) and qmlEngine(obj)
+            // should behave identically to QML singleton types.
+            q->setContextForObject(o, new QQmlContext(q->rootContext(), q));
+        }
+        singletonInstances.insert(type, value);
+
+    } else if (siinfo->qobjectCallback) {
+        QObject *o = siinfo->qobjectCallback(q, q);
+        if (!o) {
+            qFatal("qmlRegisterSingletonType(): \"%s\" is not available because the callback function returns a null pointer.",
+                   qPrintable(QString::fromUtf8(type.typeName())));
+        }
+        // if this object can use a property cache, create it now
+        QQmlData::ensurePropertyCache(q, o);
+        // even though the object is defined in C++, qmlContext(obj) and qmlEngine(obj)
+        // should behave identically to QML singleton types.
+        q->setContextForObject(o, new QQmlContext(q->rootContext(), q));
+        value = q->newQObject(o);
+        singletonInstances.insert(type, value);
+
+    } else if (!siinfo->url.isEmpty()) {
+        QQmlComponent component(q, siinfo->url, QQmlComponent::PreferSynchronous);
+        QObject *o = component.beginCreate(q->rootContext());
+        value = q->newQObject(o);
+        singletonInstances.insert(type, value);
+        component.completeCreate();
+    }
+
+    return value;
+}
+
+void QQmlEnginePrivate::destroySingletonInstance(const QQmlType &type)
+{
+    Q_ASSERT(type.isSingleton() || type.isCompositeSingleton());
+
+    QObject* o = singletonInstances.take(type).toQObject();
+    if (o) {
+        QQmlData *ddata = QQmlData::get(o, false);
+        if (type.singletonInstanceInfo()->url.isEmpty() && ddata && ddata->indestructible && ddata->explicitIndestructibleSet)
+            return;
+        delete o;
+    }
+}
+
 bool QQmlEnginePrivate::isTypeLoaded(const QUrl &url) const
 {
     return typeLoader.isTypeLoaded(url);
diff --git a/src/qml/qml/qqmlengine.h b/src/qml/qml/qqmlengine.h
index 871e6bd9b4..da91c8fa15 100644
--- a/src/qml/qml/qqmlengine.h
+++ b/src/qml/qml/qqmlengine.h
@@ -175,12 +175,7 @@ Q_QML_EXPORT QJSValue QQmlEngine::singletonInstance<QJSValue>(int qmlTypeId);
 
 template<typename T>
 T QQmlEngine::singletonInstance(int qmlTypeId) {
-    QJSValue instance = singletonInstance<QJSValue>(qmlTypeId);
-    if (!instance.isQObject())
-        return nullptr;
-
-    QObject *object = instance.toQObject();
-    return qobject_cast<T>(object);
+    return qobject_cast<T>(singletonInstance<QJSValue>(qmlTypeId).toQObject());
 }
 
 QT_END_NAMESPACE
diff --git a/src/qml/qml/qqmlengine_p.h b/src/qml/qml/qqmlengine_p.h
index dab4e54cd6..4f7fb79593 100644
--- a/src/qml/qml/qqmlengine_p.h
+++ b/src/qml/qml/qqmlengine_p.h
@@ -229,6 +229,10 @@ public:
     bool isTypeLoaded(const QUrl &url) const;
     bool isScriptLoaded(const QUrl &url) const;
 
+    template <typename T>
+    T singletonInstance(const QQmlType &type);
+    void destroySingletonInstance(const QQmlType &type);
+
     void sendQuit();
     void sendExit(int retCode = 0);
     void warning(const QQmlError &);
@@ -262,6 +266,8 @@ public:
     mutable QMutex networkAccessManagerMutex;
 
 private:
+    QHash<QQmlType, QJSValue> singletonInstances;
+
     // These members must be protected by a QQmlEnginePrivate::Locker as they are required by
     // the threaded loader.  Only access them through their respective accessor methods.
     QHash<int, QV4::CompiledData::CompilationUnit *> m_compositeTypes;
@@ -437,6 +443,14 @@ QQmlEnginePrivate *QQmlEnginePrivate::get(QV4::ExecutionEngine *e)
     return get(qmlEngine);
 }
 
+template<>
+Q_QML_PRIVATE_EXPORT QJSValue QQmlEnginePrivate::singletonInstance<QJSValue>(const QQmlType &type);
+
+template<typename T>
+T QQmlEnginePrivate::singletonInstance(const QQmlType &type) {
+    return qobject_cast<T>(singletonInstance<QJSValue>(type).toQObject());
+}
+
 QT_END_NAMESPACE
 
 #endif // QQMLENGINE_P_H
diff --git a/src/qml/qml/qqmljavascriptexpression_p.h b/src/qml/qml/qqmljavascriptexpression_p.h
index 453c8ab8a8..92f2ccbb4a 100644
--- a/src/qml/qml/qqmljavascriptexpression_p.h
+++ b/src/qml/qml/qqmljavascriptexpression_p.h
@@ -182,7 +182,7 @@ private:
     QV4::Function *m_v4Function;
 };
 
-class QQmlPropertyCapture
+class Q_QML_PRIVATE_EXPORT QQmlPropertyCapture
 {
 public:
     QQmlPropertyCapture(QQmlEngine *engine, QQmlJavaScriptExpression *e, QQmlJavaScriptExpression::DeleteWatcher *w)
diff --git a/src/qml/qml/qqmlmetatype.cpp b/src/qml/qml/qqmlmetatype.cpp
index 32f281b4f2..09df23de51 100644
--- a/src/qml/qml/qqmlmetatype.cpp
+++ b/src/qml/qml/qqmlmetatype.cpp
@@ -76,6 +76,8 @@ public:
     const QQmlMetaTypeData *operator->() const { return data; }
     operator const QQmlMetaTypeData *() const { return data; }
 
+    bool isValid() const { return data != nullptr; }
+
 private:
     QMutexLocker locker;
     LockedData *data = nullptr;
@@ -143,12 +145,6 @@ static QQmlTypePrivate *createQQmlType(QQmlMetaTypeData *data, const QString &el
     d->baseMetaObject = type.metaObject;
     d->extraData.cd->attachedPropertiesFunc = type.attachedPropertiesFunction;
     d->extraData.cd->attachedPropertiesType = type.attachedPropertiesMetaObject;
-    if (d->extraData.cd->attachedPropertiesType) {
-        d->extraData.cd->attachedPropertiesId = data->attachedPropertyId(d->baseMetaObject,
-                                                                         d->index);
-    } else {
-        d->extraData.cd->attachedPropertiesId = -1;
-    }
     d->extraData.cd->parserStatusCast = type.parserStatusCast;
     d->extraData.cd->propertyValueSourceCast = type.valueSourceCast;
     d->extraData.cd->propertyValueInterceptorCast = type.valueInterceptorCast;
@@ -599,19 +595,6 @@ void QQmlMetaType::registerUndeletableType(const QQmlType &dtype)
     data->undeletableTypes.insert(dtype);
 }
 
-int QQmlMetaType::registerAttachedPropertyId(const QMetaObject *metaObject, int index)
-{
-    QQmlMetaTypeDataPtr data;
-    return data->attachedPropertyId(metaObject, index);
-}
-
-bool QQmlMetaType::unregisterAttachedPropertyId(const QMetaObject *metaObject, int index)
-{
-    QQmlMetaTypeDataPtr data;
-    // This is run from the QQmlType dtor. QQmlTypes in user code can outlive QQmlMetaTypeData.
-    return data ? data->removeAttachedPropertyId(metaObject, index) : false;
-}
-
 static bool namespaceContainsRegistrations(const QQmlMetaTypeData *data, const QString &uri,
                                            int majorVersion)
 {
@@ -916,6 +899,7 @@ int QQmlMetaType::listType(int id)
         return 0;
 }
 
+#if QT_DEPRECATED_SINCE(5, 14)
 int QQmlMetaType::attachedPropertiesFuncId(QQmlEnginePrivate *engine, const QMetaObject *mo)
 {
     QQmlMetaTypeDataPtr data;
@@ -937,6 +921,16 @@ QQmlAttachedPropertiesFunc QQmlMetaType::attachedPropertiesFuncById(QQmlEnginePr
     QQmlMetaTypeDataPtr data;
     return data->types.at(id).attachedPropertiesFunction(engine);
 }
+#endif
+
+QQmlAttachedPropertiesFunc QQmlMetaType::attachedPropertiesFunc(QQmlEnginePrivate *engine,
+                                                                const QMetaObject *mo)
+{
+    QQmlMetaTypeDataPtr data;
+
+    QQmlType type(data->metaObjectToType.value(mo));
+    return type.attachedPropertiesFunction(engine);
+}
 
 QMetaProperty QQmlMetaType::defaultProperty(const QMetaObject *metaObject)
 {
@@ -1216,6 +1210,10 @@ void QQmlMetaType::freeUnusedTypesAndCaches()
 {
     QQmlMetaTypeDataPtr data;
 
+    // in case this is being called during program exit, `data` might be destructed already
+    if (!data.isValid())
+        return;
+
     bool deletedAtLeastOneType;
     do {
         deletedAtLeastOneType = false;
diff --git a/src/qml/qml/qqmlmetatype_p.h b/src/qml/qml/qqmlmetatype_p.h
index dde9cf68d7..9af982d1c3 100644
--- a/src/qml/qml/qqmlmetatype_p.h
+++ b/src/qml/qml/qqmlmetatype_p.h
@@ -88,9 +88,6 @@ public:
 
     static void registerUndeletableType(const QQmlType &dtype);
 
-    static int registerAttachedPropertyId(const QMetaObject *metaObject, int index);
-    static bool unregisterAttachedPropertyId(const QMetaObject *metaObject, int index);
-
     static QList<QString> qmlTypeNames();
     static QList<QQmlType> qmlTypes();
     static QList<QQmlType> qmlSingletonTypes();
@@ -122,8 +119,14 @@ public:
     static QObject *toQObject(const QVariant &, bool *ok = nullptr);
 
     static int listType(int);
-    static int attachedPropertiesFuncId(QQmlEnginePrivate *engine, const QMetaObject *);
-    static QQmlAttachedPropertiesFunc attachedPropertiesFuncById(QQmlEnginePrivate *, int);
+#if QT_DEPRECATED_SINCE(5, 14)
+    static QT_DEPRECATED int attachedPropertiesFuncId(QQmlEnginePrivate *engine,
+                                                      const QMetaObject *);
+    static QT_DEPRECATED QQmlAttachedPropertiesFunc attachedPropertiesFuncById(QQmlEnginePrivate *,
+                                                                               int);
+#endif
+    static QQmlAttachedPropertiesFunc attachedPropertiesFunc(QQmlEnginePrivate *,
+                                                             const QMetaObject *);
 
     enum TypeCategory { Unknown, Object, List };
     static TypeCategory typeCategory(int);
diff --git a/src/qml/qml/qqmlmetatypedata_p.h b/src/qml/qml/qqmlmetatypedata_p.h
index c45bc16280..5239b635ce 100644
--- a/src/qml/qml/qqmlmetatypedata_p.h
+++ b/src/qml/qml/qqmlmetatypedata_p.h
@@ -134,27 +134,8 @@ struct QQmlMetaTypeData
             qWarning("%s", message.toUtf8().constData());
     }
 
-    int attachedPropertyId(const QMetaObject *metaObject, int ownIndex)
-    {
-        auto iter = attachedPropertyIds.find(metaObject);
-        return (iter == attachedPropertyIds.end())
-                ? *attachedPropertyIds.insert(metaObject, ownIndex)
-                : *iter;
-    }
-
-    bool removeAttachedPropertyId(const QMetaObject *metaObject, int ownIndex)
-    {
-        auto iter = attachedPropertyIds.find(metaObject);
-        if (iter != attachedPropertyIds.end() && *iter == ownIndex) {
-            attachedPropertyIds.erase(iter);
-            return true;
-        }
-        return false;
-    }
-
 private:
     QStringList *m_typeRegistrationFailures = nullptr;
-    QHash<const QMetaObject *, int> attachedPropertyIds;
 };
 
 inline uint qHash(const QQmlMetaTypeData::VersionedUri &v)
diff --git a/src/qml/qml/qqmlobjectcreator.cpp b/src/qml/qml/qqmlobjectcreator.cpp
index c36b3ed386..26d3b5b6c1 100644
--- a/src/qml/qml/qqmlobjectcreator.cpp
+++ b/src/qml/qml/qqmlobjectcreator.cpp
@@ -824,8 +824,8 @@ bool QQmlObjectCreator::setPropertyBinding(const QQmlPropertyData *bindingProper
             else
                 return false;
         }
-        const int id = attachedType.attachedPropertiesId(QQmlEnginePrivate::get(engine));
-        QObject *qmlObject = qmlAttachedPropertiesObjectById(id, _qobject);
+        QObject *qmlObject = qmlAttachedPropertiesObject(
+                _qobject, attachedType.attachedPropertiesFunction(QQmlEnginePrivate::get(engine)));
         if (!populateInstance(binding->value.objectIndex, qmlObject, qmlObject, /*value type property*/nullptr))
             return false;
         return true;
diff --git a/src/qml/qml/qqmlprivate.h b/src/qml/qml/qqmlprivate.h
index c0232a7691..fa05b3fe19 100644
--- a/src/qml/qml/qqmlprivate.h
+++ b/src/qml/qml/qqmlprivate.h
@@ -77,6 +77,11 @@ typedef void (*IRLoaderFunction)(Document *, const QQmlPrivate::CachedQmlUnit *)
 
 typedef QObject *(*QQmlAttachedPropertiesFunc)(QObject *);
 
+inline uint qHash(QQmlAttachedPropertiesFunc func, uint seed = 0)
+{
+    return qHash(quintptr(func), seed);
+}
+
 template <typename TYPE>
 class QQmlTypeInfo
 {
diff --git a/src/qml/qml/qqmlproperty.cpp b/src/qml/qml/qqmlproperty.cpp
index 000b88ebaa..c8166695ba 100644
--- a/src/qml/qml/qqmlproperty.cpp
+++ b/src/qml/qml/qqmlproperty.cpp
@@ -277,7 +277,7 @@ void QQmlPropertyPrivate::initProperty(QObject *obj, const QString &name)
                         QQmlAttachedPropertiesFunc func = r.type.attachedPropertiesFunction(enginePrivate);
                         if (!func) return; // Not an attachable type
 
-                        currentObject = qmlAttachedPropertiesObjectById(r.type.attachedPropertiesId(enginePrivate), currentObject);
+                        currentObject = qmlAttachedPropertiesObject(currentObject, func);
                         if (!currentObject) return; // Something is broken with the attachable type
                     } else if (r.importNamespace) {
                         if ((ii + 1) == path.count()) return; // No type following the namespace
@@ -289,7 +289,7 @@ void QQmlPropertyPrivate::initProperty(QObject *obj, const QString &name)
                         QQmlAttachedPropertiesFunc func = r.type.attachedPropertiesFunction(enginePrivate);
                         if (!func) return; // Not an attachable type
 
-                        currentObject = qmlAttachedPropertiesObjectById(r.type.attachedPropertiesId(enginePrivate), currentObject);
+                        currentObject = qmlAttachedPropertiesObject(currentObject, func);
                         if (!currentObject) return; // Something is broken with the attachable type
 
                     } else if (r.scriptIndex != -1) {
diff --git a/src/qml/qml/qqmltype.cpp b/src/qml/qml/qqmltype.cpp
index 88eedec061..926e2810d5 100644
--- a/src/qml/qml/qqmltype.cpp
+++ b/src/qml/qml/qqmltype.cpp
@@ -51,70 +51,6 @@
 
 QT_BEGIN_NAMESPACE
 
-void QQmlType::SingletonInstanceInfo::init(QQmlEngine *e)
-{
-    if (scriptCallback && scriptApi(e).isUndefined()) {
-        QJSValue value = scriptCallback(e, e);
-        if (value.isQObject()) {
-            QObject *o = value.toQObject();
-            // even though the object is defined in C++, qmlContext(obj) and qmlEngine(obj)
-            // should behave identically to QML singleton types.
-            e->setContextForObject(o, new QQmlContext(e->rootContext(), e));
-        }
-        setScriptApi(e, value);
-    } else if (qobjectCallback && !qobjectApi(e)) {
-        QObject *o = qobjectCallback(e, e);
-        setQObjectApi(e, o);
-        if (!o) {
-            qFatal("qmlRegisterSingletonType(): \"%s\" is not available because the callback function returns a null pointer.", qPrintable(typeName));
-        }
-        // if this object can use a property cache, create it now
-        QQmlData::ensurePropertyCache(e, o);
-        // even though the object is defined in C++, qmlContext(obj) and qmlEngine(obj)
-        // should behave identically to QML singleton types.
-        e->setContextForObject(o, new QQmlContext(e->rootContext(), e));
-    } else if (!url.isEmpty() && !qobjectApi(e)) {
-        QQmlComponent component(e, url, QQmlComponent::PreferSynchronous);
-        QObject *o = component.beginCreate(e->rootContext());
-        setQObjectApi(e, o);
-        if (o)
-            component.completeCreate();
-    }
-}
-
-void QQmlType::SingletonInstanceInfo::destroy(QQmlEngine *e)
-{
-    // cleans up the engine-specific singleton instances if they exist.
-    scriptApis.remove(e);
-    QObject *o = qobjectApis.take(e);
-    if (o) {
-        QQmlData *ddata = QQmlData::get(o, false);
-        if (url.isEmpty() && ddata && ddata->indestructible && ddata->explicitIndestructibleSet)
-            return;
-        delete o;
-    }
-}
-
-void QQmlType::SingletonInstanceInfo::setQObjectApi(QQmlEngine *e, QObject *o)
-{
-    qobjectApis.insert(e, o);
-}
-
-QObject *QQmlType::SingletonInstanceInfo::qobjectApi(QQmlEngine *e) const
-{
-    return qobjectApis.value(e);
-}
-
-void QQmlType::SingletonInstanceInfo::setScriptApi(QQmlEngine *e, const QJSValue &v)
-{
-    scriptApis.insert(e, v);
-}
-
-QJSValue QQmlType::SingletonInstanceInfo::scriptApi(QQmlEngine *e) const
-{
-    return scriptApis.value(e);
-}
-
 QQmlTypePrivate::QQmlTypePrivate(QQmlType::RegistrationType type)
     : regType(type), iid(nullptr), typeId(0), listId(0), revision(0),
     containsRevisionedAttributes(false), baseMetaObject(nullptr),
@@ -156,10 +92,6 @@ QQmlTypePrivate::~QQmlTypePrivate()
     qDeleteAll(scopedEnums);
     switch (regType) {
     case QQmlType::CppType:
-        // If attached properties were successfully registered, deregister them.
-        // (They may not have been registered if some other type used the same baseMetaObject)
-        if (extraData.cd->attachedPropertiesType)
-            QQmlMetaType::unregisterAttachedPropertyId(baseMetaObject, index);
         delete extraData.cd->customParser;
         delete extraData.cd;
         break;
@@ -640,6 +572,16 @@ bool QQmlType::isCompositeSingleton() const
     return d && d->regType == CompositeSingletonType;
 }
 
+bool QQmlType::isQObjectSingleton() const
+{
+    return d && d->regType == SingletonType && d->extraData.sd->singletonInstanceInfo->qobjectCallback;
+}
+
+bool QQmlType::isQJSValueSingleton() const
+{
+    return d && d->regType == SingletonType && d->extraData.sd->singletonInstanceInfo->scriptCallback;
+}
+
 int QQmlType::typeId() const
 {
     return d ? d->typeId : -1;
@@ -708,6 +650,7 @@ const QMetaObject *QQmlType::attachedPropertiesType(QQmlEnginePrivate *engine) c
     return base.attachedPropertiesType(engine);
 }
 
+#if QT_DEPRECATED_SINCE(5, 14)
 /*
 This is the id passed to qmlAttachedPropertiesById().  This is different from the index
 for the case that a single class is registered under two or more names (eg. Item in
@@ -718,13 +661,14 @@ int QQmlType::attachedPropertiesId(QQmlEnginePrivate *engine) const
     if (!d)
         return -1;
     if (d->regType == CppType)
-        return d->extraData.cd->attachedPropertiesId;
+        return d->extraData.cd->attachedPropertiesType ? d->index : -1;
 
     QQmlType base;
     if (d->regType == CompositeType)
         base = resolveCompositeBaseType(engine);
     return base.attachedPropertiesId(engine);
 }
+#endif
 
 int QQmlType::parserStatusCast() const
 {
diff --git a/src/qml/qml/qqmltype_p.h b/src/qml/qml/qqmltype_p.h
index 0e59b1be06..1d65a08c8f 100644
--- a/src/qml/qml/qqmltype_p.h
+++ b/src/qml/qml/qqmltype_p.h
@@ -118,6 +118,8 @@ public:
     bool isInterface() const;
     bool isComposite() const;
     bool isCompositeSingleton() const;
+    bool isQObjectSingleton() const;
+    bool isQJSValueSingleton() const;
 
     int typeId() const;
     int qListTypeId() const;
@@ -129,7 +131,9 @@ public:
 
     QQmlAttachedPropertiesFunc attachedPropertiesFunction(QQmlEnginePrivate *engine) const;
     const QMetaObject *attachedPropertiesType(QQmlEnginePrivate *engine) const;
-    int attachedPropertiesId(QQmlEnginePrivate *engine) const;
+#if QT_DEPRECATED_SINCE(5, 14)
+    QT_DEPRECATED int attachedPropertiesId(QQmlEnginePrivate *engine) const;
+#endif
 
     int parserStatusCast() const;
     const char *interfaceIId() const;
@@ -138,28 +142,13 @@ public:
 
     int index() const;
 
-    class Q_QML_PRIVATE_EXPORT SingletonInstanceInfo
+    struct Q_QML_PRIVATE_EXPORT SingletonInstanceInfo
     {
-    public:
-        SingletonInstanceInfo()
-            : scriptCallback(nullptr), qobjectCallback(nullptr), instanceMetaObject(nullptr) {}
-
-        QJSValue (*scriptCallback)(QQmlEngine *, QJSEngine *);
-        QObject *(*qobjectCallback)(QQmlEngine *, QJSEngine *);
-        const QMetaObject *instanceMetaObject;
+        QJSValue (*scriptCallback)(QQmlEngine *, QJSEngine *) = nullptr;
+        QObject *(*qobjectCallback)(QQmlEngine *, QJSEngine *) = nullptr;
+        const QMetaObject *instanceMetaObject = nullptr;
         QString typeName;
         QUrl url; // used by composite singletons
-
-        void setQObjectApi(QQmlEngine *, QObject *);
-        QObject *qobjectApi(QQmlEngine *) const;
-        void setScriptApi(QQmlEngine *, const QJSValue &);
-        QJSValue scriptApi(QQmlEngine *) const;
-
-        void init(QQmlEngine *);
-        void destroy(QQmlEngine *);
-
-        QHash<QQmlEngine *, QJSValue> scriptApis;
-        QHash<QQmlEngine *, QObject *> qobjectApis;
     };
     SingletonInstanceInfo *singletonInstanceInfo() const;
 
diff --git a/src/qml/qml/qqmltype_p_p.h b/src/qml/qml/qqmltype_p_p.h
index b317aff740..d381e11df4 100644
--- a/src/qml/qml/qqmltype_p_p.h
+++ b/src/qml/qml/qqmltype_p_p.h
@@ -83,7 +83,6 @@ public:
         QQmlCustomParser *customParser;
         QQmlAttachedPropertiesFunc attachedPropertiesFunc;
         const QMetaObject *attachedPropertiesType;
-        int attachedPropertiesId;
         int propertyValueSourceCast;
         int propertyValueInterceptorCast;
         bool registerEnumClassesUnscoped;
diff --git a/src/qml/qml/qqmltypewrapper.cpp b/src/qml/qml/qqmltypewrapper.cpp
index 86513b5ff8..236daac75c 100644
--- a/src/qml/qml/qqmltypewrapper.cpp
+++ b/src/qml/qml/qqmltypewrapper.cpp
@@ -89,25 +89,21 @@ QObject* QQmlTypeWrapper::singletonObject() const
     if (!isSingleton())
         return nullptr;
 
-    QQmlEngine *e = engine()->qmlEngine();
-    QQmlType::SingletonInstanceInfo *siinfo = d()->type().singletonInstanceInfo();
-    siinfo->init(e);
-    return siinfo->qobjectApi(e);
+    QQmlEnginePrivate *e = QQmlEnginePrivate::get(engine()->qmlEngine());
+    return e->singletonInstance<QObject*>(d()->type());
 }
 
 QVariant QQmlTypeWrapper::toVariant() const
 {
-    // Only Singleton type wrappers can be converted to a variant.
     if (!isSingleton())
-        return QVariant();
+        return QVariant::fromValue<QObject *>(d()->object);
 
-    QQmlEngine *e = engine()->qmlEngine();
-    QQmlType::SingletonInstanceInfo *siinfo = d()->type().singletonInstanceInfo();
-    siinfo->init(e);
-    if (QObject *qobjectSingleton = siinfo->qobjectApi(e))
-        return QVariant::fromValue<QObject*>(qobjectSingleton);
+    QQmlEnginePrivate *e = QQmlEnginePrivate::get(engine()->qmlEngine());
+    const QQmlType type = d()->type();
+    if (type.isQJSValueSingleton())
+        return QVariant::fromValue<QJSValue>(e->singletonInstance<QJSValue>(type));
 
-    return QVariant::fromValue<QJSValue>(siinfo->scriptApi(e));
+    return QVariant::fromValue<QObject*>(e->singletonInstance<QObject*>(type));
 }
 
 
@@ -195,50 +191,51 @@ ReturnedValue QQmlTypeWrapper::virtualGet(const Managed *m, PropertyKey id, cons
 
         // singleton types are handled differently to other types.
         if (type.isSingleton()) {
-            QQmlEngine *e = v4->qmlEngine();
-            QQmlType::SingletonInstanceInfo *siinfo = type.singletonInstanceInfo();
-            siinfo->init(e);
-
-            QObject *qobjectSingleton = siinfo->qobjectApi(e);
-            if (qobjectSingleton) {
-
-                // check for enum value
-                const bool includeEnums = w->d()->mode == Heap::QQmlTypeWrapper::IncludeEnums;
-                if (includeEnums && name->startsWithUpper()) {
-                    bool ok = false;
-                    int value = enumForSingleton(v4, name, qobjectSingleton, type, &ok);
-                    if (ok)
-                        return QV4::Value::fromInt32(value).asReturnedValue();
-
-                    value = type.scopedEnumIndex(QQmlEnginePrivate::get(v4->qmlEngine()), name, &ok);
-                    if (ok) {
-                        Scoped<QQmlScopedEnumWrapper> enumWrapper(scope, v4->memoryManager->allocate<QQmlScopedEnumWrapper>());
-                        enumWrapper->d()->typePrivate = type.priv();
-                        QQmlType::refHandle(enumWrapper->d()->typePrivate);
-                        enumWrapper->d()->scopeEnumIndex = value;
-                        return enumWrapper.asReturnedValue();
+            QQmlEnginePrivate *e = QQmlEnginePrivate::get(v4->qmlEngine());
+            QJSValue scriptSingleton;
+            if (type.isQObjectSingleton() || type.isCompositeSingleton()) {
+                if (QObject *qobjectSingleton = e->singletonInstance<QObject*>(type)) {
+                    // check for enum value
+                    const bool includeEnums = w->d()->mode == Heap::QQmlTypeWrapper::IncludeEnums;
+                    if (includeEnums && name->startsWithUpper()) {
+                        bool ok = false;
+                        int value = enumForSingleton(v4, name, qobjectSingleton, type, &ok);
+                        if (ok)
+                            return QV4::Value::fromInt32(value).asReturnedValue();
+
+                        value = type.scopedEnumIndex(QQmlEnginePrivate::get(v4->qmlEngine()), name, &ok);
+                        if (ok) {
+                            Scoped<QQmlScopedEnumWrapper> enumWrapper(scope, v4->memoryManager->allocate<QQmlScopedEnumWrapper>());
+                            enumWrapper->d()->typePrivate = type.priv();
+                            QQmlType::refHandle(enumWrapper->d()->typePrivate);
+                            enumWrapper->d()->scopeEnumIndex = value;
+                            return enumWrapper.asReturnedValue();
+                        }
                     }
-                }
 
-                // check for property.
-                bool ok;
-                const ReturnedValue result = QV4::QObjectWrapper::getQmlProperty(v4, context, qobjectSingleton, name, QV4::QObjectWrapper::IgnoreRevision, &ok);
-                if (hasProperty)
-                    *hasProperty = ok;
-
-                // Warn when attempting to access a lowercased enum value, singleton case
-                if (!ok && includeEnums && !name->startsWithUpper()) {
-                    enumForSingleton(v4, name, qobjectSingleton, type, &ok);
-                    if (ok)
-                        return throwLowercaseEnumError(v4, name, type);
-                }
+                    // check for property.
+                    bool ok;
+                    const ReturnedValue result = QV4::QObjectWrapper::getQmlProperty(v4, context, qobjectSingleton, name, QV4::QObjectWrapper::IgnoreRevision, &ok);
+                    if (hasProperty)
+                        *hasProperty = ok;
+
+                    // Warn when attempting to access a lowercased enum value, singleton case
+                    if (!ok && includeEnums && !name->startsWithUpper()) {
+                        enumForSingleton(v4, name, qobjectSingleton, type, &ok);
+                        if (ok)
+                            return throwLowercaseEnumError(v4, name, type);
+                    }
 
-                return result;
-            } else if (!siinfo->scriptApi(e).isUndefined()) {
-                // NOTE: if used in a binding, changes will not trigger re-evaluation since non-NOTIFYable.
-                QV4::ScopedObject o(scope, QJSValuePrivate::convertedToValue(v4, siinfo->scriptApi(e)));
-                if (!!o)
-                    return o->get(name);
+                    return result;
+                }
+            } else if (type.isQJSValueSingleton()) {
+                QJSValue scriptSingleton = e->singletonInstance<QJSValue>(type);
+                if (!scriptSingleton.isUndefined()) {
+                    // NOTE: if used in a binding, changes will not trigger re-evaluation since non-NOTIFYable.
+                    QV4::ScopedObject o(scope, QJSValuePrivate::convertedToValue(v4, scriptSingleton));
+                    if (!!o)
+                        return o->get(name);
+                }
             }
 
             // Fall through to base implementation
@@ -263,7 +260,9 @@ ReturnedValue QQmlTypeWrapper::virtualGet(const Managed *m, PropertyKey id, cons
                 // Fall through to base implementation
 
             } else if (w->d()->object) {
-                QObject *ao = qmlAttachedPropertiesObjectById(type.attachedPropertiesId(QQmlEnginePrivate::get(v4->qmlEngine())), object);
+                QObject *ao = qmlAttachedPropertiesObject(
+                        object,
+                        type.attachedPropertiesFunction(QQmlEnginePrivate::get(v4->qmlEngine())));
                 if (ao)
                     return QV4::QObjectWrapper::getQmlProperty(v4, context, ao, name, QV4::QObjectWrapper::IgnoreRevision, hasProperty);
 
@@ -335,26 +334,28 @@ bool QQmlTypeWrapper::virtualPut(Managed *m, PropertyKey id, const Value &value,
     if (type.isValid() && !type.isSingleton() && w->d()->object) {
         QObject *object = w->d()->object;
         QQmlEngine *e = scope.engine->qmlEngine();
-        QObject *ao = qmlAttachedPropertiesObjectById(type.attachedPropertiesId(QQmlEnginePrivate::get(e)), object);
+        QObject *ao = qmlAttachedPropertiesObject(
+                object, type.attachedPropertiesFunction(QQmlEnginePrivate::get(e)));
         if (ao)
             return QV4::QObjectWrapper::setQmlProperty(scope.engine, context, ao, name, QV4::QObjectWrapper::IgnoreRevision, value);
         return false;
     } else if (type.isSingleton()) {
-        QQmlEngine *e = scope.engine->qmlEngine();
-        QQmlType::SingletonInstanceInfo *siinfo = type.singletonInstanceInfo();
-        siinfo->init(e);
-
-        QObject *qobjectSingleton = siinfo->qobjectApi(e);
-        if (qobjectSingleton) {
-            return QV4::QObjectWrapper::setQmlProperty(scope.engine, context, qobjectSingleton, name, QV4::QObjectWrapper::IgnoreRevision, value);
-        } else if (!siinfo->scriptApi(e).isUndefined()) {
-            QV4::ScopedObject apiprivate(scope, QJSValuePrivate::convertedToValue(scope.engine, siinfo->scriptApi(e)));
-            if (!apiprivate) {
-                QString error = QLatin1String("Cannot assign to read-only property \"") + name->toQString() + QLatin1Char('\"');
-                scope.engine->throwError(error);
-                return false;
-            } else {
-                return apiprivate->put(name, value);
+        QQmlEnginePrivate *e = QQmlEnginePrivate::get(scope.engine->qmlEngine());
+        if (type.isQObjectSingleton() || type.isCompositeSingleton()) {
+            if (QObject *qobjectSingleton = e->singletonInstance<QObject*>(type))
+                return QV4::QObjectWrapper::setQmlProperty(scope.engine, context, qobjectSingleton, name, QV4::QObjectWrapper::IgnoreRevision, value);
+
+        } else {
+            QJSValue scriptSingleton = e->singletonInstance<QJSValue>(type);
+            if (!scriptSingleton.isUndefined()) {
+                QV4::ScopedObject apiprivate(scope, QJSValuePrivate::convertedToValue(scope.engine, scriptSingleton));
+                if (!apiprivate) {
+                    QString error = QLatin1String("Cannot assign to read-only property \"") + name->toQString() + QLatin1Char('\"');
+                    scope.engine->throwError(error);
+                    return false;
+                } else {
+                    return apiprivate->put(name, value);
+                }
             }
         }
     }
@@ -446,27 +447,25 @@ ReturnedValue QQmlTypeWrapper::virtualResolveLookupGetter(const Object *object,
     if (type.isValid()) {
 
         if (type.isSingleton()) {
-            QQmlEngine *e = engine->qmlEngine();
-            QQmlType::SingletonInstanceInfo *siinfo = type.singletonInstanceInfo();
-            siinfo->init(e);
-
-            QObject *qobjectSingleton = siinfo->qobjectApi(e);
-            if (qobjectSingleton) {
-
-                const bool includeEnums = w->d()->mode == Heap::QQmlTypeWrapper::IncludeEnums;
-                if (!includeEnums || !name->startsWithUpper()) {
-                    QQmlData *ddata = QQmlData::get(qobjectSingleton, false);
-                    if (ddata && ddata->propertyCache) {
-                        ScopedValue val(scope, Value::fromReturnedValue(QV4::QObjectWrapper::wrap(engine, qobjectSingleton)));
-                        QQmlPropertyData *property = ddata->propertyCache->property(name.getPointer(), qobjectSingleton, qmlContext);
-                        if (property) {
-                            lookup->qobjectLookup.ic = This->internalClass();
-                            lookup->qobjectLookup.staticQObject = static_cast<Heap::QObjectWrapper *>(val->heapObject());
-                            lookup->qobjectLookup.propertyCache = ddata->propertyCache;
-                            lookup->qobjectLookup.propertyCache->addref();
-                            lookup->qobjectLookup.propertyData = property;
-                            lookup->getter = QV4::QObjectWrapper::lookupGetter;
-                            return lookup->getter(lookup, engine, *This);
+            QQmlEnginePrivate *e = QQmlEnginePrivate::get(engine->qmlEngine());
+            if (type.isQObjectSingleton() || type.isCompositeSingleton()) {
+                if (QObject *qobjectSingleton = e->singletonInstance<QObject*>(type)) {
+                    const bool includeEnums = w->d()->mode == Heap::QQmlTypeWrapper::IncludeEnums;
+                    if (!includeEnums || !name->startsWithUpper()) {
+                        QQmlData *ddata = QQmlData::get(qobjectSingleton, false);
+                        if (ddata && ddata->propertyCache) {
+                            ScopedValue val(scope, Value::fromReturnedValue(QV4::QObjectWrapper::wrap(engine, qobjectSingleton)));
+                            QQmlPropertyData *property = ddata->propertyCache->property(name.getPointer(), qobjectSingleton, qmlContext);
+                            if (property) {
+                                lookup->qobjectLookup.ic = This->internalClass();
+                                lookup->qobjectLookup.staticQObject = static_cast<Heap::QObjectWrapper *>(val->heapObject());
+                                lookup->qobjectLookup.propertyCache = ddata->propertyCache;
+                                lookup->qobjectLookup.propertyCache->addref();
+                                lookup->qobjectLookup.propertyData = property;
+                                lookup->getter = QV4::QObjectWrapper::lookupGetter;
+                                return lookup->getter(lookup, engine, *This);
+                            }
+                            // Fall through to base implementation
                         }
                         // Fall through to base implementation
                     }