Merge 5.14 into 5.14.2

Change-Id: Ib4b26bad47a850cde6253fb3422aae34b2cf622b

36 files changed, 300 insertions, 158 deletions

diff --git a/examples/widgets/itemviews/spreadsheet/printview.cpp b/examples/widgets/itemviews/spreadsheet/printview.cpp
index 7db1a6bad9..7700b4ed6a 100644
--- a/examples/widgets/itemviews/spreadsheet/printview.cpp
+++ b/examples/widgets/itemviews/spreadsheet/printview.cpp
@@ -50,8 +50,12 @@
 
 #include "printview.h"
 
-#ifndef QT_NO_PRINTER
-#include <QPrinter>
+#if defined(QT_PRINTSUPPORT_LIB)
+#  include <QtPrintSupport/qtprintsupportglobal.h>
+
+#  if QT_CONFIG(printer)
+#    include <QPrinter>
+#  endif
 #endif
 
 PrintView::PrintView()
@@ -62,9 +66,11 @@ PrintView::PrintView()
 
 void PrintView::print(QPrinter *printer)
 {
-#ifndef QT_NO_PRINTER
+#if defined(QT_PRINTSUPPORT_LIB) && QT_CONFIG(printer)
     resize(printer->width(), printer->height());
     render(printer);
+#else
+    Q_UNUSED(printer)
 #endif
 }
 
diff --git a/examples/widgets/itemviews/spreadsheet/spreadsheet.cpp b/examples/widgets/itemviews/spreadsheet/spreadsheet.cpp
index fc7fbb872c..ac8ea7d437 100644
--- a/examples/widgets/itemviews/spreadsheet/spreadsheet.cpp
+++ b/examples/widgets/itemviews/spreadsheet/spreadsheet.cpp
@@ -638,7 +638,7 @@ QString encode_pos(int row, int col)
 
 void SpreadSheet::print()
 {
-#if QT_CONFIG(printpreviewdialog)
+#if defined(QT_PRINTSUPPORT_LIB) && QT_CONFIG(printpreviewdialog)
     QPrinter printer(QPrinter::ScreenResolution);
     QPrintPreviewDialog dlg(&printer);
     PrintView view;
diff --git a/examples/widgets/richtext/textedit/textedit.cpp b/examples/widgets/richtext/textedit/textedit.cpp
index 7708b25a24..c9173bcb99 100644
--- a/examples/widgets/richtext/textedit/textedit.cpp
+++ b/examples/widgets/richtext/textedit/textedit.cpp
@@ -197,7 +197,7 @@ void TextEdit::setupFileActions()
     a->setPriority(QAction::LowPriority);
     menu->addSeparator();
 
-#ifndef QT_NO_PRINTER
+#if defined(QT_PRINTSUPPORT_LIB) && QT_CONFIG(printer)
     const QIcon printIcon = QIcon::fromTheme("document-print", QIcon(rsrcPath + "/fileprint.png"));
     a = menu->addAction(printIcon, tr("&Print..."), this, &TextEdit::filePrint);
     a->setPriority(QAction::LowPriority);
@@ -559,7 +559,7 @@ void TextEdit::filePrint()
 
 void TextEdit::filePrintPreview()
 {
-#if QT_CONFIG(printpreviewdialog)
+#if defined(QT_PRINTSUPPORT_LIB) && QT_CONFIG(printpreviewdialog)
     QPrinter printer(QPrinter::HighResolution);
     QPrintPreviewDialog preview(&printer, this);
     connect(&preview, &QPrintPreviewDialog::paintRequested, this, &TextEdit::printPreview);
@@ -569,17 +569,17 @@ void TextEdit::filePrintPreview()
 
 void TextEdit::printPreview(QPrinter *printer)
 {
-#ifdef QT_NO_PRINTER
-    Q_UNUSED(printer);
-#else
+#if defined(QT_PRINTSUPPORT_LIB) && QT_CONFIG(printer)
     textEdit->print(printer);
+#else
+    Q_UNUSED(printer)
 #endif
 }
 
 
 void TextEdit::filePrintPdf()
 {
-#ifndef QT_NO_PRINTER
+#if defined(QT_PRINTSUPPORT_LIB) && QT_CONFIG(printer)
 //! [0]
     QFileDialog fileDialog(this, tr("Export PDF"));
     fileDialog.setAcceptMode(QFileDialog::AcceptSave);
diff --git a/examples/widgets/tutorials/notepad/notepad.pro b/examples/widgets/tutorials/notepad/notepad.pro
index 6451f22735..efe16fc2a2 100644
--- a/examples/widgets/tutorials/notepad/notepad.pro
+++ b/examples/widgets/tutorials/notepad/notepad.pro
@@ -1,6 +1,8 @@
 TEMPLATE = app
 TARGET = notepad
 
+QT += widgets
+
 qtHaveModule(printsupport): QT += printsupport
 requires(qtConfig(fontdialog))
 
diff --git a/examples/widgets/widgets/imageviewer/imageviewer.cpp b/examples/widgets/widgets/imageviewer/imageviewer.cpp
index 70a4cda984..1ed55ca6cb 100644
--- a/examples/widgets/widgets/imageviewer/imageviewer.cpp
+++ b/examples/widgets/widgets/imageviewer/imageviewer.cpp
@@ -69,10 +69,11 @@
 #include <QStatusBar>
 
 #if defined(QT_PRINTSUPPORT_LIB)
-#include <QtPrintSupport/qtprintsupportglobal.h>
-#if QT_CONFIG(printdialog)
-#include <QPrintDialog>
-#endif
+#  include <QtPrintSupport/qtprintsupportglobal.h>
+
+#  if QT_CONFIG(printdialog)
+#    include <QPrintDialog>
+#  endif
 #endif
 
 //! [0]
diff --git a/examples/widgets/widgets/imageviewer/imageviewer.h b/examples/widgets/widgets/imageviewer/imageviewer.h
index 49c7ac205b..9c8388d470 100644
--- a/examples/widgets/widgets/imageviewer/imageviewer.h
+++ b/examples/widgets/widgets/imageviewer/imageviewer.h
@@ -53,8 +53,12 @@
 
 #include <QMainWindow>
 #include <QImage>
-#ifndef QT_NO_PRINTER
-#include <QPrinter>
+#if defined(QT_PRINTSUPPORT_LIB)
+#  include <QtPrintSupport/qtprintsupportglobal.h>
+
+#  if QT_CONFIG(printer)
+#    include <QPrinter>
+#  endif
 #endif
 
 QT_BEGIN_NAMESPACE
@@ -100,7 +104,7 @@ private:
     QScrollArea *scrollArea;
     double scaleFactor = 1;
 
-#ifndef QT_NO_PRINTER
+#if defined(QT_PRINTSUPPORT_LIB) && QT_CONFIG(printer)
     QPrinter printer;
 #endif
 
diff --git a/src/corelib/itemmodels/qsortfilterproxymodel.cpp b/src/corelib/itemmodels/qsortfilterproxymodel.cpp
index 61d37d5062..122b95ed57 100644
--- a/src/corelib/itemmodels/qsortfilterproxymodel.cpp
+++ b/src/corelib/itemmodels/qsortfilterproxymodel.cpp
@@ -1949,8 +1949,9 @@ void QSortFilterProxyModelPrivate::_q_sourceColumnsMoved(
     example.)
 
     If you are working with large amounts of filtering and have to invoke
-    invalidateFilter() repeatedly, using reset() may be more efficient,
-    depending on the implementation of your model. However, reset() returns the
+    invalidateFilter() repeatedly, using beginResetModel() / endResetModel() may
+    be more efficient, depending on the implementation of your model. However,
+    beginResetModel() / endResetModel() returns the
     proxy model to its original state, losing selection information, and will
     cause the proxy model to be repopulated.
 
diff --git a/src/corelib/kernel/qmetatype.cpp b/src/corelib/kernel/qmetatype.cpp
index 356a675517..9fc0659cf2 100644
--- a/src/corelib/kernel/qmetatype.cpp
+++ b/src/corelib/kernel/qmetatype.cpp
@@ -589,7 +589,8 @@ QMetaTypeComparatorRegistry;
 typedef QMetaTypeFunctionRegistry<QtPrivate::AbstractDebugStreamFunction,int>
 QMetaTypeDebugStreamRegistry;
 
-Q_STATIC_ASSERT(std::is_pod<QMetaTypeInterface>::value);
+Q_STATIC_ASSERT(std::is_trivial<QMetaTypeInterface>::value);
+Q_STATIC_ASSERT(std::is_standard_layout<QMetaTypeInterface>::value);
 
 Q_DECLARE_TYPEINFO(QCustomTypeInfo, Q_MOVABLE_TYPE);
 Q_GLOBAL_STATIC(QVector<QCustomTypeInfo>, customTypes)
diff --git a/src/corelib/plugin/qfactoryloader.cpp b/src/corelib/plugin/qfactoryloader.cpp
index 18f10c9b43..9a6a69676d 100644
--- a/src/corelib/plugin/qfactoryloader.cpp
+++ b/src/corelib/plugin/qfactoryloader.cpp
@@ -389,17 +389,12 @@ QObject *QFactoryLoader::instance(int index) const
     QMutexLocker lock(&d->mutex);
     if (index < d->libraryList.size()) {
         QLibraryPrivate *library = d->libraryList.at(index);
-        if (library->instance || library->loadPlugin()) {
-            if (!library->inst)
-                library->inst = library->instance();
-            QObject *obj = library->inst.data();
-            if (obj) {
-                if (!obj->parent())
-                    obj->moveToThread(QCoreApplicationPrivate::mainThread());
-                return obj;
-            }
+        if (QObject *obj = library->pluginInstance()) {
+            if (!obj->parent())
+                obj->moveToThread(QCoreApplicationPrivate::mainThread());
+            return obj;
         }
-        return 0;
+        return nullptr;
     }
     index -= d->libraryList.size();
     lock.unlock();
diff --git a/src/corelib/plugin/qlibrary.cpp b/src/corelib/plugin/qlibrary.cpp
index eeaa3c18ec..ddb053c26f 100644
--- a/src/corelib/plugin/qlibrary.cpp
+++ b/src/corelib/plugin/qlibrary.cpp
@@ -407,7 +407,7 @@ inline void QLibraryStore::cleanup()
         QLibraryPrivate *lib = it.value();
         if (lib->libraryRefCount.loadRelaxed() == 1) {
             if (lib->libraryUnloadCount.loadRelaxed() > 0) {
-                Q_ASSERT(lib->pHnd);
+                Q_ASSERT(lib->pHnd.loadRelaxed());
                 lib->libraryUnloadCount.storeRelaxed(1);
 #ifdef __GLIBC__
                 // glibc has a bug in unloading from global destructors
@@ -498,8 +498,7 @@ inline void QLibraryStore::releaseLibrary(QLibraryPrivate *lib)
 }
 
 QLibraryPrivate::QLibraryPrivate(const QString &canonicalFileName, const QString &version, QLibrary::LoadHints loadHints)
-    : pHnd(0), fileName(canonicalFileName), fullVersion(version), instance(0),
-      libraryRefCount(0), libraryUnloadCount(0), pluginState(MightBeAPlugin)
+    : fileName(canonicalFileName), fullVersion(version), pluginState(MightBeAPlugin)
 {
     loadHintsInt.storeRelaxed(loadHints);
     if (canonicalFileName.isEmpty())
@@ -519,7 +518,7 @@ QLibraryPrivate::~QLibraryPrivate()
 void QLibraryPrivate::mergeLoadHints(QLibrary::LoadHints lh)
 {
     // if the library is already loaded, we can't change the load hints
-    if (pHnd)
+    if (pHnd.loadRelaxed())
         return;
 
     loadHintsInt.storeRelaxed(lh);
@@ -527,7 +526,7 @@ void QLibraryPrivate::mergeLoadHints(QLibrary::LoadHints lh)
 
 QFunctionPointer QLibraryPrivate::resolve(const char *symbol)
 {
-    if (!pHnd)
+    if (!pHnd.loadRelaxed())
         return 0;
     return resolve_sys(symbol);
 }
@@ -539,9 +538,36 @@ void QLibraryPrivate::setLoadHints(QLibrary::LoadHints lh)
     mergeLoadHints(lh);
 }
 
+QObject *QLibraryPrivate::pluginInstance()
+{
+    // first, check if the instance is cached and hasn't been deleted
+    QObject *obj = (QMutexLocker(&mutex), inst.data());
+    if (obj)
+        return obj;
+
+    // We need to call the plugin's factory function. Is that cached?
+    // skip increasing the reference count (why? -Thiago)
+    QtPluginInstanceFunction factory = instanceFactory.loadAcquire();
+    if (!factory)
+        factory = loadPlugin();
+
+    if (!factory)
+        return nullptr;
+
+    obj = factory();
+
+    // cache again
+    QMutexLocker locker(&mutex);
+    if (inst)
+        obj = inst;
+    else
+        inst = obj;
+    return obj;
+}
+
 bool QLibraryPrivate::load()
 {
-    if (pHnd) {
+    if (pHnd.loadRelaxed()) {
         libraryUnloadCount.ref();
         return true;
     }
@@ -550,7 +576,9 @@ bool QLibraryPrivate::load()
 
     Q_TRACE(QLibraryPrivate_load_entry, fileName);
 
+    mutex.lock();
     bool ret = load_sys();
+    mutex.unlock();
     if (qt_debug_component()) {
         if (ret) {
             qDebug() << "loaded library" << fileName;
@@ -573,9 +601,10 @@ bool QLibraryPrivate::load()
 
 bool QLibraryPrivate::unload(UnloadFlag flag)
 {
-    if (!pHnd)
+    if (!pHnd.loadRelaxed())
         return false;
     if (libraryUnloadCount.loadRelaxed() > 0 && !libraryUnloadCount.deref()) { // only unload if ALL QLibrary instance wanted to
+        QMutexLocker locker(&mutex);
         delete inst.data();
         if (flag == NoUnloadSys || unload_sys()) {
             if (qt_debug_component())
@@ -584,12 +613,13 @@ bool QLibraryPrivate::unload(UnloadFlag flag)
             //when the library is unloaded, we release the reference on it so that 'this'
             //can get deleted
             libraryRefCount.deref();
-            pHnd = 0;
-            instance = 0;
+            pHnd.storeRelaxed(nullptr);
+            instanceFactory.storeRelaxed(nullptr);
+            return true;
         }
     }
 
-    return (pHnd == 0);
+    return false;
 }
 
 void QLibraryPrivate::release()
@@ -597,22 +627,23 @@ void QLibraryPrivate::release()
     QLibraryStore::releaseLibrary(this);
 }
 
-bool QLibraryPrivate::loadPlugin()
+QtPluginInstanceFunction QLibraryPrivate::loadPlugin()
 {
-    if (instance) {
+    if (auto ptr = instanceFactory.loadAcquire()) {
         libraryUnloadCount.ref();
-        return true;
+        return ptr;
     }
     if (pluginState == IsNotAPlugin)
-        return false;
+        return nullptr;
     if (load()) {
-        instance = (QtPluginInstanceFunction)resolve("qt_plugin_instance");
-        return instance;
+        auto ptr = reinterpret_cast<QtPluginInstanceFunction>(resolve("qt_plugin_instance"));
+        instanceFactory.storeRelease(ptr); // two threads may store the same value
+        return ptr;
     }
     if (qt_debug_component())
         qWarning() << "QLibraryPrivate::loadPlugin failed on" << fileName << ":" << errorString;
     pluginState = IsNotAPlugin;
-    return false;
+    return nullptr;
 }
 
 /*!
@@ -719,6 +750,7 @@ bool QLibraryPrivate::isPlugin()
 
 void QLibraryPrivate::updatePluginState()
 {
+    QMutexLocker locker(&mutex);
     errorString.clear();
     if (pluginState != MightBeAPlugin)
         return;
@@ -739,7 +771,7 @@ void QLibraryPrivate::updatePluginState()
     }
 #endif
 
-    if (!pHnd) {
+    if (!pHnd.loadRelaxed()) {
         // scan for the plugin metadata without loading
         success = findPatternUnloaded(fileName, this);
     } else {
@@ -803,7 +835,7 @@ bool QLibrary::load()
     if (!d)
         return false;
     if (did_load)
-        return d->pHnd;
+        return d->pHnd.loadRelaxed();
     did_load = true;
     return d->load();
 }
@@ -839,7 +871,7 @@ bool QLibrary::unload()
  */
 bool QLibrary::isLoaded() const
 {
-    return d && d->pHnd;
+    return d && d->pHnd.loadRelaxed();
 }
 
 
@@ -950,8 +982,10 @@ void QLibrary::setFileName(const QString &fileName)
 
 QString QLibrary::fileName() const
 {
-    if (d)
+    if (d) {
+        QMutexLocker locker(&d->mutex);
         return d->qualifiedFileName.isEmpty() ? d->fileName : d->qualifiedFileName;
+    }
     return QString();
 }
 
@@ -1092,7 +1126,12 @@ QFunctionPointer QLibrary::resolve(const QString &fileName, const QString &versi
 */
 QString QLibrary::errorString() const
 {
-    return (!d || d->errorString.isEmpty()) ? tr("Unknown error") : d->errorString;
+    QString str;
+    if (d) {
+        QMutexLocker locker(&d->mutex);
+        str = d->errorString;
+    }
+    return str.isEmpty() ? tr("Unknown error") : str;
 }
 
 /*!
diff --git a/src/corelib/plugin/qlibrary_p.h b/src/corelib/plugin/qlibrary_p.h
index db5afac98e..d756126c64 100644
--- a/src/corelib/plugin/qlibrary_p.h
+++ b/src/corelib/plugin/qlibrary_p.h
@@ -54,10 +54,10 @@
 
 #include <QtCore/private/qglobal_p.h>
 #include "QtCore/qlibrary.h"
+#include "QtCore/qmutex.h"
 #include "QtCore/qpointer.h"
 #include "QtCore/qstringlist.h"
 #include "QtCore/qplugin.h"
-#include "QtCore/qsharedpointer.h"
 #ifdef Q_OS_WIN
 #  include "QtCore/qt_windows.h"
 #endif
@@ -72,21 +72,18 @@ class QLibraryStore;
 class QLibraryPrivate
 {
 public:
-
 #ifdef Q_OS_WIN
-    HINSTANCE
+    using Handle = HINSTANCE;
 #else
-    void *
+    using Handle = void *;
 #endif
-    pHnd;
-
     enum UnloadFlag { UnloadSys, NoUnloadSys };
 
-    QString fileName, qualifiedFileName;
-    QString fullVersion;
+    const QString fileName;
+    const QString fullVersion;
 
     bool load();
-    bool loadPlugin(); // loads and resolves instance
+    QtPluginInstanceFunction loadPlugin(); // loads and resolves instance
     bool unload(UnloadFlag flag = UnloadSys);
     void release();
     QFunctionPointer resolve(const char *);
@@ -94,17 +91,22 @@ public:
     QLibrary::LoadHints loadHints() const
     { return QLibrary::LoadHints(loadHintsInt.loadRelaxed()); }
     void setLoadHints(QLibrary::LoadHints lh);
+    QObject *pluginInstance();
 
     static QLibraryPrivate *findOrCreate(const QString &fileName, const QString &version = QString(),
                                          QLibrary::LoadHints loadHints = nullptr);
     static QStringList suffixes_sys(const QString &fullVersion);
     static QStringList prefixes_sys();
 
-    QPointer<QObject> inst;
-    QtPluginInstanceFunction instance;
-    QJsonObject metaData;
+    QAtomicPointer<std::remove_pointer<QtPluginInstanceFunction>::type> instanceFactory;
+    QAtomicPointer<std::remove_pointer<Handle>::type> pHnd;
 
+    // the mutex protects the fields below
+    QMutex mutex;
+    QPointer<QObject> inst;         // used by QFactoryLoader
+    QJsonObject metaData;
     QString errorString;
+    QString qualifiedFileName;
 
     void updatePluginState();
     bool isPlugin();
diff --git a/src/corelib/plugin/qlibrary_unix.cpp b/src/corelib/plugin/qlibrary_unix.cpp
index 135b82cd37..29813e5863 100644
--- a/src/corelib/plugin/qlibrary_unix.cpp
+++ b/src/corelib/plugin/qlibrary_unix.cpp
@@ -214,8 +214,9 @@ bool QLibraryPrivate::load_sys()
 #endif
 
     bool retry = true;
-    for(int prefix = 0; retry && !pHnd && prefix < prefixes.size(); prefix++) {
-        for(int suffix = 0; retry && !pHnd && suffix < suffixes.size(); suffix++) {
+    Handle hnd = nullptr;
+    for (int prefix = 0; retry && !hnd && prefix < prefixes.size(); prefix++) {
+        for (int suffix = 0; retry && !hnd && suffix < suffixes.size(); suffix++) {
             if (!prefixes.at(prefix).isEmpty() && name.startsWith(prefixes.at(prefix)))
                 continue;
             if (path.isEmpty() && prefixes.at(prefix).contains(QLatin1Char('/')))
@@ -232,7 +233,7 @@ bool QLibraryPrivate::load_sys()
                 attempt = path + prefixes.at(prefix) + name + suffixes.at(suffix);
             }
 
-            pHnd = dlopen(QFile::encodeName(attempt), dlFlags);
+            hnd = dlopen(QFile::encodeName(attempt), dlFlags);
 #ifdef Q_OS_ANDROID
             if (!pHnd) {
                 auto attemptFromBundle = attempt;
@@ -248,7 +249,7 @@ bool QLibraryPrivate::load_sys()
             }
 #endif
 
-            if (!pHnd && fileName.startsWith(QLatin1Char('/')) && QFile::exists(attempt)) {
+            if (!hnd && fileName.startsWith(QLatin1Char('/')) && QFile::exists(attempt)) {
                 // We only want to continue if dlopen failed due to that the shared library did not exist.
                 // However, we are only able to apply this check for absolute filenames (since they are
                 // not influenced by the content of LD_LIBRARY_PATH, /etc/ld.so.cache, DT_RPATH etc...)
@@ -259,7 +260,7 @@ bool QLibraryPrivate::load_sys()
     }
 
 #ifdef Q_OS_MAC
-    if (!pHnd) {
+    if (!hnd) {
         QByteArray utf8Bundle = fileName.toUtf8();
         QCFType<CFURLRef> bundleUrl = CFURLCreateFromFileSystemRepresentation(NULL, reinterpret_cast<const UInt8*>(utf8Bundle.data()), utf8Bundle.length(), true);
         QCFType<CFBundleRef> bundle = CFBundleCreate(NULL, bundleUrl);
@@ -268,23 +269,24 @@ bool QLibraryPrivate::load_sys()
             char executableFile[FILENAME_MAX];
             CFURLGetFileSystemRepresentation(url, true, reinterpret_cast<UInt8*>(executableFile), FILENAME_MAX);
             attempt = QString::fromUtf8(executableFile);
-            pHnd = dlopen(QFile::encodeName(attempt), dlFlags);
+            hnd = dlopen(QFile::encodeName(attempt), dlFlags);
         }
     }
 #endif
-    if (!pHnd) {
+    if (!hnd) {
         errorString = QLibrary::tr("Cannot load library %1: %2").arg(fileName, qdlerror());
     }
-    if (pHnd) {
+    if (hnd) {
         qualifiedFileName = attempt;
         errorString.clear();
     }
-    return (pHnd != 0);
+    pHnd.storeRelaxed(hnd);
+    return (hnd != nullptr);
 }
 
 bool QLibraryPrivate::unload_sys()
 {
-    if (dlclose(pHnd)) {
+    if (dlclose(pHnd.loadAcquire())) {
 #if defined (Q_OS_QNX)                // Workaround until fixed in QNX; fixes crash in
         char *error = dlerror();      // QtDeclarative auto test "qqmlenginecleanup" for instance
         if (!qstrcmp(error, "Shared objects still referenced")) // On QNX that's only "informative"
@@ -316,13 +318,7 @@ Q_CORE_EXPORT QFunctionPointer qt_mac_resolve_sys(void *handle, const char *symb
 
 QFunctionPointer QLibraryPrivate::resolve_sys(const char* symbol)
 {
-    QFunctionPointer address = QFunctionPointer(dlsym(pHnd, symbol));
-    if (!address) {
-        errorString = QLibrary::tr("Cannot resolve symbol \"%1\" in %2: %3").arg(
-            QString::fromLatin1(symbol), fileName, qdlerror());
-    } else {
-        errorString.clear();
-    }
+    QFunctionPointer address = QFunctionPointer(dlsym(pHnd.loadAcquire(), symbol));
     return address;
 }
 
diff --git a/src/corelib/plugin/qlibrary_win.cpp b/src/corelib/plugin/qlibrary_win.cpp
index 05a93d467e..000bf76276 100644
--- a/src/corelib/plugin/qlibrary_win.cpp
+++ b/src/corelib/plugin/qlibrary_win.cpp
@@ -95,26 +95,27 @@ bool QLibraryPrivate::load_sys()
         attempts.prepend(QDir::rootPath() + fileName);
 #endif
 
+    Handle hnd = nullptr;
     for (const QString &attempt : qAsConst(attempts)) {
 #ifndef Q_OS_WINRT
-        pHnd = LoadLibrary(reinterpret_cast<const wchar_t*>(QDir::toNativeSeparators(attempt).utf16()));
+        hnd = LoadLibrary(reinterpret_cast<const wchar_t*>(QDir::toNativeSeparators(attempt).utf16()));
 #else // Q_OS_WINRT
         QString path = QDir::toNativeSeparators(QDir::current().relativeFilePath(attempt));
-        pHnd = LoadPackagedLibrary(reinterpret_cast<LPCWSTR>(path.utf16()), 0);
-        if (pHnd)
+        hnd = LoadPackagedLibrary(reinterpret_cast<LPCWSTR>(path.utf16()), 0);
+        if (hnd)
             qualifiedFileName = attempt;
 #endif // !Q_OS_WINRT
 
         // If we have a handle or the last error is something other than "unable
         // to find the module", then bail out
-        if (pHnd || ::GetLastError() != ERROR_MOD_NOT_FOUND)
+        if (hnd || ::GetLastError() != ERROR_MOD_NOT_FOUND)
             break;
     }
 
 #ifndef Q_OS_WINRT
     SetErrorMode(oldmode);
 #endif
-    if (!pHnd) {
+    if (!hnd) {
         errorString = QLibrary::tr("Cannot load library %1: %2").arg(
                     QDir::toNativeSeparators(fileName), qt_error_string());
     } else {
@@ -123,7 +124,7 @@ bool QLibraryPrivate::load_sys()
 
 #ifndef Q_OS_WINRT
         wchar_t buffer[MAX_PATH];
-        ::GetModuleFileName(pHnd, buffer, MAX_PATH);
+        ::GetModuleFileName(hnd, buffer, MAX_PATH);
 
         QString moduleFileName = QString::fromWCharArray(buffer);
         moduleFileName.remove(0, 1 + moduleFileName.lastIndexOf(QLatin1Char('\\')));
@@ -138,19 +139,20 @@ bool QLibraryPrivate::load_sys()
             HMODULE hmod;
             bool ok = GetModuleHandleEx(GET_MODULE_HANDLE_EX_FLAG_PIN |
                                         GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
-                                        reinterpret_cast<const wchar_t *>(pHnd),
+                                        reinterpret_cast<const wchar_t *>(hnd),
                                         &hmod);
-            Q_ASSERT(!ok || hmod == pHnd);
+            Q_ASSERT(!ok || hmod == hnd);
             Q_UNUSED(ok);
         }
 #endif // !Q_OS_WINRT
     }
-    return (pHnd != 0);
+    pHnd.storeRelaxed(hnd);
+    return (pHnd != nullptr);
 }
 
 bool QLibraryPrivate::unload_sys()
 {
-    if (!FreeLibrary(pHnd)) {
+    if (!FreeLibrary(pHnd.loadAcquire())) {
         errorString = QLibrary::tr("Cannot unload library %1: %2").arg(
                     QDir::toNativeSeparators(fileName),  qt_error_string());
         return false;
@@ -161,13 +163,7 @@ bool QLibraryPrivate::unload_sys()
 
 QFunctionPointer QLibraryPrivate::resolve_sys(const char* symbol)
 {
-    FARPROC address = GetProcAddress(pHnd, symbol);
-    if (!address) {
-        errorString = QLibrary::tr("Cannot resolve symbol \"%1\" in %2: %3").arg(
-            QString::fromLatin1(symbol), QDir::toNativeSeparators(fileName), qt_error_string());
-    } else {
-        errorString.clear();
-    }
+    FARPROC address = GetProcAddress(pHnd.loadAcquire(), symbol);
     return QFunctionPointer(address);
 }
 QT_END_NAMESPACE
diff --git a/src/corelib/plugin/qpluginloader.cpp b/src/corelib/plugin/qpluginloader.cpp
index dac8502dae..0e12793d5e 100644
--- a/src/corelib/plugin/qpluginloader.cpp
+++ b/src/corelib/plugin/qpluginloader.cpp
@@ -196,9 +196,7 @@ QObject *QPluginLoader::instance()
 {
     if (!isLoaded() && !load())
         return 0;
-    if (!d->inst && d->instance)
-        d->inst = d->instance();
-    return d->inst.data();
+    return d->pluginInstance();
 }
 
 /*!
@@ -233,7 +231,7 @@ bool QPluginLoader::load()
     if (!d || d->fileName.isEmpty())
         return false;
     if (did_load)
-        return d->pHnd && d->instance;
+        return d->pHnd && d->instanceFactory.loadAcquire();
     if (!d->isPlugin())
         return false;
     did_load = true;
@@ -275,7 +273,7 @@ bool QPluginLoader::unload()
  */
 bool QPluginLoader::isLoaded() const
 {
-    return d && d->pHnd && d->instance;
+    return d && d->pHnd && d->instanceFactory.loadRelaxed();
 }
 
 #if defined(QT_SHARED)
diff --git a/src/corelib/serialization/qcborvalue_p.h b/src/corelib/serialization/qcborvalue_p.h
index 48818e4c63..a74ac2ba10 100644
--- a/src/corelib/serialization/qcborvalue_p.h
+++ b/src/corelib/serialization/qcborvalue_p.h
@@ -115,7 +115,8 @@ struct ByteData
     QStringView asStringView() const{ return QStringView(utf16(), len / 2); }
     QString asQStringRaw() const    { return QString::fromRawData(utf16(), len / 2); }
 };
-Q_STATIC_ASSERT(std::is_pod<ByteData>::value);
+Q_STATIC_ASSERT(std::is_trivial<ByteData>::value);
+Q_STATIC_ASSERT(std::is_standard_layout<ByteData>::value);
 } // namespace QtCbor
 
 Q_DECLARE_TYPEINFO(QtCbor::Element, Q_PRIMITIVE_TYPE);
diff --git a/src/gui/kernel/qwindow.cpp b/src/gui/kernel/qwindow.cpp
index 0a4277c118..9cb851a7a2 100644
--- a/src/gui/kernel/qwindow.cpp
+++ b/src/gui/kernel/qwindow.cpp
@@ -1666,7 +1666,7 @@ void QWindow::setGeometry(const QRect &rect)
         if (newScreen && isTopLevel())
             nativeRect = QHighDpi::toNativePixels(rect, newScreen);
         else
-            nativeRect = QHighDpi::toNativePixels(rect, this);
+            nativeRect = QHighDpi::toNativeLocalPosition(rect, newScreen);
         d->platformWindow->setGeometry(nativeRect);
     } else {
         d->geometry = rect;
@@ -1717,8 +1717,12 @@ QScreen *QWindowPrivate::screenForGeometry(const QRect &newGeometry) const
 QRect QWindow::geometry() const
 {
     Q_D(const QWindow);
-    if (d->platformWindow)
-        return QHighDpi::fromNativePixels(d->platformWindow->geometry(), this);
+    if (d->platformWindow) {
+        const auto nativeGeometry = d->platformWindow->geometry();
+        return isTopLevel()
+            ? QHighDpi::fromNativePixels(nativeGeometry, this)
+            : QHighDpi::fromNativeLocalPosition(nativeGeometry, this);
+    }
     return d->geometry;
 }
 
diff --git a/src/gui/kernel/qwindowsysteminterface.cpp b/src/gui/kernel/qwindowsysteminterface.cpp
index 8457282bed..8f2927901a 100644
--- a/src/gui/kernel/qwindowsysteminterface.cpp
+++ b/src/gui/kernel/qwindowsysteminterface.cpp
@@ -296,14 +296,21 @@ QWindowSystemInterfacePrivate::GeometryChangeEvent::GeometryChangeEvent(QWindow
     , window(window)
     , newGeometry(newGeometry)
 {
-    if (const QPlatformWindow *pw = window->handle())
-        requestedGeometry = QHighDpi::fromNativePixels(pw->QPlatformWindow::geometry(), window);
+    if (const QPlatformWindow *pw = window->handle()) {
+        const auto nativeGeometry = pw->QPlatformWindow::geometry();
+        requestedGeometry = window->isTopLevel()
+            ? QHighDpi::fromNativePixels(nativeGeometry, window)
+            : QHighDpi::fromNativeLocalPosition(nativeGeometry, window);
+    }
 }
 
 QT_DEFINE_QPA_EVENT_HANDLER(void, handleGeometryChange, QWindow *window, const QRect &newRect)
 {
     Q_ASSERT(window);
-    QWindowSystemInterfacePrivate::GeometryChangeEvent *e = new QWindowSystemInterfacePrivate::GeometryChangeEvent(window, QHighDpi::fromNativePixels(newRect, window));
+    const auto newRectDi = window->isTopLevel()
+        ? QHighDpi::fromNativePixels(newRect, window)
+        : QHighDpi::fromNativeLocalPosition(newRect, window);
+    auto e = new QWindowSystemInterfacePrivate::GeometryChangeEvent(window, newRectDi);
     if (window->handle()) {
         // Persist the new geometry so that QWindow::geometry() can be queried in the resize event
         window->handle()->QPlatformWindow::setGeometry(newRect);
diff --git a/src/gui/text/qtextmarkdownimporter.cpp b/src/gui/text/qtextmarkdownimporter.cpp
index 7e18a10895..5e75e7816b 100644
--- a/src/gui/text/qtextmarkdownimporter.cpp
+++ b/src/gui/text/qtextmarkdownimporter.cpp
@@ -577,7 +577,10 @@ void QTextMarkdownImporter::insertBlock()
     QTextBlockFormat blockFormat;
     if (!m_listStack.isEmpty() && !m_needsInsertList && m_listItem) {
         QTextList *list = m_listStack.top();
-        blockFormat = list->item(list->count() - 1).blockFormat();
+        if (list)
+            blockFormat = list->item(list->count() - 1).blockFormat();
+        else
+            qWarning() << "attempted to insert into a list that no longer exists";
     }
     if (m_blockQuoteDepth) {
         blockFormat.setProperty(QTextFormat::BlockQuoteLevel, m_blockQuoteDepth);
@@ -607,7 +610,7 @@ void QTextMarkdownImporter::insertBlock()
     }
     if (m_needsInsertList) {
         m_listStack.push(m_cursor->createList(m_listFormat));
-    } else if (!m_listStack.isEmpty() && m_listItem) {
+    } else if (!m_listStack.isEmpty() && m_listItem && m_listStack.top()) {
         m_listStack.top()->add(m_cursor->block());
     }
     m_needsInsertList = false;
diff --git a/src/gui/text/qtextmarkdownimporter_p.h b/src/gui/text/qtextmarkdownimporter_p.h
index f450da5eb3..f12b725d8e 100644
--- a/src/gui/text/qtextmarkdownimporter_p.h
+++ b/src/gui/text/qtextmarkdownimporter_p.h
@@ -56,6 +56,7 @@
 #include <QtGui/qpalette.h>
 #include <QtGui/qtextdocument.h>
 #include <QtGui/qtextlist.h>
+#include <QtCore/qpointer.h>
 #include <QtCore/qstack.h>
 
 QT_BEGIN_NAMESPACE
@@ -113,7 +114,7 @@ private:
 #endif
     QString m_blockCodeLanguage;
     QVector<int> m_nonEmptyTableCells; // in the current row
-    QStack<QTextList *> m_listStack;
+    QStack<QPointer<QTextList>> m_listStack;
     QStack<QTextCharFormat> m_spanFormatStack;
     QFont m_monoFont;
     QPalette m_palette;
diff --git a/src/platformsupport/devicediscovery/qdevicediscovery_udev.cpp b/src/platformsupport/devicediscovery/qdevicediscovery_udev.cpp
index f601a196ca..c2413c131d 100644
--- a/src/platformsupport/devicediscovery/qdevicediscovery_udev.cpp
+++ b/src/platformsupport/devicediscovery/qdevicediscovery_udev.cpp
@@ -46,7 +46,11 @@
 #include <QSocketNotifier>
 #include <QLoggingCategory>
 
+#ifdef Q_OS_FREEBSD
+#include <dev/evdev/input.h>
+#else
 #include <linux/input.h>
+#endif
 
 QT_BEGIN_NAMESPACE
 
diff --git a/src/plugins/platforms/windows/qwindowsintegration.cpp b/src/plugins/platforms/windows/qwindowsintegration.cpp
index 09117f663d..d37b405db8 100644
--- a/src/plugins/platforms/windows/qwindowsintegration.cpp
+++ b/src/plugins/platforms/windows/qwindowsintegration.cpp
@@ -334,7 +334,9 @@ QPlatformWindow *QWindowsIntegration::createPlatformWindow(QWindow *window) cons
 
     QWindowsWindowData requested;
     requested.flags = window->flags();
-    requested.geometry = QHighDpi::toNativePixels(window->geometry(), window);
+    requested.geometry = window->isTopLevel()
+        ? QHighDpi::toNativePixels(window->geometry(), window)
+        : QHighDpi::toNativeLocalPosition(window->geometry(), window);
     // Apply custom margins (see  QWindowsWindow::setCustomMargins())).
     const QVariant customMarginsV = window->property("_q_windowsCustomMargins");
     if (customMarginsV.isValid())
diff --git a/src/plugins/platforms/xcb/qxcbatom.cpp b/src/plugins/platforms/xcb/qxcbatom.cpp
index ecb73cb90b..d366564dd6 100644
--- a/src/plugins/platforms/xcb/qxcbatom.cpp
+++ b/src/plugins/platforms/xcb/qxcbatom.cpp
@@ -122,6 +122,7 @@ static const char *xcb_atomnames = {
     "_NET_WM_STATE_MODAL\0"
     "_NET_WM_STATE_STAYS_ON_TOP\0"
     "_NET_WM_STATE_DEMANDS_ATTENTION\0"
+    "_NET_WM_STATE_HIDDEN\0"
 
     "_NET_WM_USER_TIME\0"
     "_NET_WM_USER_TIME_WINDOW\0"
diff --git a/src/plugins/platforms/xcb/qxcbatom.h b/src/plugins/platforms/xcb/qxcbatom.h
index 233d2eadb7..80b5887395 100644
--- a/src/plugins/platforms/xcb/qxcbatom.h
+++ b/src/plugins/platforms/xcb/qxcbatom.h
@@ -123,6 +123,7 @@ public:
         _NET_WM_STATE_MODAL,
         _NET_WM_STATE_STAYS_ON_TOP,
         _NET_WM_STATE_DEMANDS_ATTENTION,
+        _NET_WM_STATE_HIDDEN,
 
         _NET_WM_USER_TIME,
         _NET_WM_USER_TIME_WINDOW,
diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index cfe048d5c4..a5974ec36e 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -276,7 +276,9 @@ void QXcbWindow::create()
 
     QXcbScreen *currentScreen = xcbScreen();
     QXcbScreen *platformScreen = parent() ? parentScreen() : initialScreen();
-    QRect rect = QHighDpi::toNativePixels(window()->geometry(), platformScreen);
+    QRect rect = parent()
+        ? QHighDpi::toNativeLocalPosition(window()->geometry(), platformScreen)
+        : QHighDpi::toNativePixels(window()->geometry(), platformScreen);
 
     if (type == Qt::Desktop) {
         m_window = platformScreen->root();
@@ -905,6 +907,8 @@ QXcbWindow::NetWmStates QXcbWindow::netWmStates()
             result |= NetWmStateStaysOnTop;
         if (statesEnd != std::find(states, statesEnd, atom(QXcbAtom::_NET_WM_STATE_DEMANDS_ATTENTION)))
             result |= NetWmStateDemandsAttention;
+        if (statesEnd != std::find(states, statesEnd, atom(QXcbAtom::_NET_WM_STATE_HIDDEN)))
+            result |= NetWmStateHidden;
     } else {
         qCDebug(lcQpaXcb, "getting net wm state (%x), empty\n", m_window);
     }
@@ -1076,6 +1080,9 @@ void QXcbWindow::setNetWmStateOnUnmappedWindow()
         states |= NetWmStateBelow;
     }
 
+    if (window()->windowStates() & Qt::WindowMinimized)
+        states |= NetWmStateHidden;
+
     if (window()->windowStates() & Qt::WindowFullScreen)
         states |= NetWmStateFullScreen;
 
@@ -1109,6 +1116,8 @@ void QXcbWindow::setNetWmStateOnUnmappedWindow()
         atoms.push_back(atom(QXcbAtom::_NET_WM_STATE_ABOVE));
     if (states & NetWmStateBelow && !atoms.contains(atom(QXcbAtom::_NET_WM_STATE_BELOW)))
         atoms.push_back(atom(QXcbAtom::_NET_WM_STATE_BELOW));
+    if (states & NetWmStateHidden && !atoms.contains(atom(QXcbAtom::_NET_WM_STATE_HIDDEN)))
+        atoms.push_back(atom(QXcbAtom::_NET_WM_STATE_HIDDEN));
     if (states & NetWmStateFullScreen && !atoms.contains(atom(QXcbAtom::_NET_WM_STATE_FULLSCREEN)))
         atoms.push_back(atom(QXcbAtom::_NET_WM_STATE_FULLSCREEN));
     if (states & NetWmStateMaximizedHorz && !atoms.contains(atom(QXcbAtom::_NET_WM_STATE_MAXIMIZED_HORZ)))
@@ -2217,10 +2226,16 @@ void QXcbWindow::handlePropertyNotifyEvent(const xcb_property_notify_event_t *ev
                                    || (data[0] == XCB_ICCCM_WM_STATE_WITHDRAWN && m_minimized));
             }
         }
-        if (m_minimized)
-            newState = Qt::WindowMinimized;
 
         const NetWmStates states = netWmStates();
+        // _NET_WM_STATE_HIDDEN should be set by the Window Manager to indicate that a window would
+        // not be visible on the screen if its desktop/viewport were active and its coordinates were
+        // within the screen bounds. The canonical example is that minimized windows should be in
+        // the _NET_WM_STATE_HIDDEN state.
+        if (m_minimized && (!connection()->wmSupport()->isSupportedByWM(NetWmStateHidden)
+                            || states.testFlag(NetWmStateHidden)))
+            newState = Qt::WindowMinimized;
+
         if (states & NetWmStateFullScreen)
             newState |= Qt::WindowFullScreen;
         if ((states & NetWmStateMaximizedHorz) && (states & NetWmStateMaximizedVert))
diff --git a/src/plugins/platforms/xcb/qxcbwindow.h b/src/plugins/platforms/xcb/qxcbwindow.h
index a808437c5a..b84250d109 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.h
+++ b/src/plugins/platforms/xcb/qxcbwindow.h
@@ -68,7 +68,8 @@ public:
         NetWmStateMaximizedVert = 0x10,
         NetWmStateModal = 0x20,
         NetWmStateStaysOnTop = 0x40,
-        NetWmStateDemandsAttention = 0x80
+        NetWmStateDemandsAttention = 0x80,
+        NetWmStateHidden = 0x100
     };
 
     Q_DECLARE_FLAGS(NetWmStates, NetWmState)
diff --git a/src/tools/uic/cpp/cppwriteinitialization.cpp b/src/tools/uic/cpp/cppwriteinitialization.cpp
index 1212c410ff..92fd6471a8 100644
--- a/src/tools/uic/cpp/cppwriteinitialization.cpp
+++ b/src/tools/uic/cpp/cppwriteinitialization.cpp
@@ -546,12 +546,19 @@ void WriteInitialization::acceptUI(DomUI *node)
 
     m_output << m_option.indent << language::endFunctionDefinition("setupUi");
 
-    if (!m_mainFormUsedInRetranslateUi && language::language() == Language::Cpp) {
-        // Mark varName as unused to avoid compiler warnings.
-        m_refreshInitialization += m_indent;
-        m_refreshInitialization += QLatin1String("(void)");
-        m_refreshInitialization += varName ;
-        m_refreshInitialization += language::eol;
+    if (!m_mainFormUsedInRetranslateUi) {
+        if (language::language() == Language::Cpp) {
+            // Mark varName as unused to avoid compiler warnings.
+            m_refreshInitialization += m_indent;
+            m_refreshInitialization += QLatin1String("(void)");
+            m_refreshInitialization += varName ;
+            m_refreshInitialization += language::eol;
+        } else if (language::language() == Language::Python) {
+            // output a 'pass' to have an empty function
+            m_refreshInitialization += m_indent;
+            m_refreshInitialization += QLatin1String("pass");
+            m_refreshInitialization += language::eol;
+        }
     }
 
     m_output << m_option.indent
diff --git a/src/xml/dom/qdom.cpp b/src/xml/dom/qdom.cpp
index 04151c3f31..04331527f9 100644
--- a/src/xml/dom/qdom.cpp
+++ b/src/xml/dom/qdom.cpp
@@ -62,6 +62,7 @@
 #include <qshareddata.h>
 #include <qdebug.h>
 #include <stdio.h>
+#include <limits>
 
 QT_BEGIN_NAMESPACE
 
@@ -4866,7 +4867,7 @@ void QDomElement::setAttribute(const QString& name, float value)
     if (!impl)
         return;
     QString x;
-    x.setNum(value);
+    x.setNum(value, 'g', 8);
     IMPL->setAttribute(name, x);
 }
 
@@ -4880,7 +4881,7 @@ void QDomElement::setAttribute(const QString& name, double value)
     if (!impl)
         return;
     QString x;
-    x.setNum(value);
+    x.setNum(value, 'g', 17);
     IMPL->setAttribute(name, x);
 }
 
@@ -5049,7 +5050,7 @@ void QDomElement::setAttributeNS(const QString nsURI, const QString& qName, doub
     if (!impl)
         return;
     QString x;
-    x.setNum(value);
+    x.setNum(value, 'g', 17);
     IMPL->setAttributeNS(nsURI, qName, x);
 }
 
diff --git a/tests/auto/corelib/kernel/qdeadlinetimer/tst_qdeadlinetimer.cpp b/tests/auto/corelib/kernel/qdeadlinetimer/tst_qdeadlinetimer.cpp
index 35c5e7cb75..db53c3f20c 100644
--- a/tests/auto/corelib/kernel/qdeadlinetimer/tst_qdeadlinetimer.cpp
+++ b/tests/auto/corelib/kernel/qdeadlinetimer/tst_qdeadlinetimer.cpp
@@ -573,12 +573,32 @@ void tst_QDeadlineTimer::stdchrono()
 
     QCOMPARE(deadline.remainingTimeAsDuration(), nanoseconds::zero());
 
+    /*
+        Call QTest::qSleep, and return true if the time actually slept is
+        within \a deviationPercent percent of the requested sleep time.
+        Otherwise, return false, in which case the test should to abort.
+    */
+    auto sleepHelper = [](int ms, int deviationPercent = 10) -> bool {
+        auto before = steady_clock::now();
+        QTest::qSleep(ms);
+        auto after = steady_clock::now();
+        auto diff = duration_cast<milliseconds>(after - before).count();
+        bool inRange = qAbs(diff - ms) < ms * deviationPercent/100.0;
+        if (!inRange)
+            qWarning() << "sleeping" << diff << "instead of" << ms << inRange;
+        return inRange;
+    };
+
     auto steady_before = steady_clock::now();
     auto system_before = system_clock::now();
 
-    QTest::qSleep(minResolution);
+    if (!sleepHelper(minResolution))
+        QSKIP("Slept too long");
     auto now = QDeadlineTimer::current(timerType);
-    QTest::qSleep(minResolution);
+    auto steady_reference = steady_clock::now();
+    auto system_reference = system_clock::now();
+    if (!sleepHelper(minResolution))
+        QSKIP("Slept too long");
 
     auto sampling_start = steady_clock::now();
     auto steady_deadline = now.deadline<steady_clock>();
@@ -599,35 +619,33 @@ void tst_QDeadlineTimer::stdchrono()
     }
 
     {
-        auto diff = duration_cast<milliseconds>(steady_after - steady_deadline);
-        QVERIFY2(diff.count() > minResolution/2, QByteArray::number(qint64(diff.count())));
-        QVERIFY2(diff.count() < 3*minResolution/2, QByteArray::number(qint64(diff.count())));
+        auto reference = duration_cast<milliseconds>(steady_after - steady_reference).count();
+        auto diff = duration_cast<milliseconds>(steady_after - steady_deadline).count();
+        QVERIFY2(diff > reference * 0.9 && diff < reference*1.1, QByteArray::number(qint64(diff)));
         QDeadlineTimer dt_after(steady_after, timerType);
         QVERIFY2(now < dt_after,
                  ("now = " + QLocale().toString(now.deadlineNSecs()) +
                  "; after = " + QLocale().toString(dt_after.deadlineNSecs())).toLatin1());
 
-        diff = duration_cast<milliseconds>(steady_deadline - steady_before);
-        QVERIFY2(diff.count() > minResolution/2, QByteArray::number(qint64(diff.count())));
-        QVERIFY2(diff.count() < 3*minResolution/2, QByteArray::number(qint64(diff.count())));
+        reference = duration_cast<milliseconds>(steady_reference - steady_before).count();
+        diff = duration_cast<milliseconds>(steady_deadline - steady_before).count();
+        QVERIFY2(diff > reference * 0.9 && diff < reference*1.1, QByteArray::number(qint64(diff)));
         QDeadlineTimer dt_before(steady_before, timerType);
         QVERIFY2(now > dt_before,
                  ("now = " + QLocale().toString(now.deadlineNSecs()) +
                  "; before = " + QLocale().toString(dt_before.deadlineNSecs())).toLatin1());
     }
     {
-        auto diff = duration_cast<milliseconds>(system_after - system_deadline);
-        QVERIFY2(diff.count() > minResolution/2, QByteArray::number(qint64(diff.count())));
-        QVERIFY2(diff.count() < 3*minResolution/2, QByteArray::number(qint64(diff.count())));
-        QDeadlineTimer dt_after(system_after, timerType);
+        auto reference = duration_cast<milliseconds>(system_after - system_reference).count();
+        auto diff = duration_cast<milliseconds>(system_after - system_deadline).count();
+        QVERIFY2(diff > reference * 0.9 && diff < reference*1.1, QByteArray::number(qint64(diff)));        QDeadlineTimer dt_after(system_after, timerType);
         QVERIFY2(now < dt_after,
                  ("now = " + QLocale().toString(now.deadlineNSecs()) +
                  "; after = " + QLocale().toString(dt_after.deadlineNSecs())).toLatin1());
 
-        diff = duration_cast<milliseconds>(system_deadline - system_before);
-        QVERIFY2(diff.count() > minResolution/2, QByteArray::number(qint64(diff.count())));
-        QVERIFY2(diff.count() < 3*minResolution/2, QByteArray::number(qint64(diff.count())));
-        QDeadlineTimer dt_before(system_before, timerType);
+        reference = duration_cast<milliseconds>(system_reference - system_before).count();
+        diff = duration_cast<milliseconds>(steady_deadline - steady_before).count();
+        QVERIFY2(diff > reference * 0.9 && diff < reference*1.1, QByteArray::number(qint64(diff)));        QDeadlineTimer dt_before(system_before, timerType);
         QVERIFY2(now > dt_before,
                  ("now = " + QLocale().toString(now.deadlineNSecs()) +
                  "; before = " + QLocale().toString(dt_before.deadlineNSecs())).toLatin1());
diff --git a/tests/auto/corelib/kernel/qelapsedtimer/BLACKLIST b/tests/auto/corelib/kernel/qelapsedtimer/BLACKLIST
deleted file mode 100644
index 2317cf886c..0000000000
--- a/tests/auto/corelib/kernel/qelapsedtimer/BLACKLIST
+++ /dev/null
@@ -1,3 +0,0 @@
-[elapsed]
-macos
-windows-10
diff --git a/tests/auto/corelib/plugin/qlibrary/tst_qlibrary.cpp b/tests/auto/corelib/plugin/qlibrary/tst_qlibrary.cpp
index e0d09b0813..50c4d9b467 100644
--- a/tests/auto/corelib/plugin/qlibrary/tst_qlibrary.cpp
+++ b/tests/auto/corelib/plugin/qlibrary/tst_qlibrary.cpp
@@ -368,7 +368,7 @@ void tst_QLibrary::errorString_data()
 
     QTest::newRow("bad load()") << (int)Load << QString("nosuchlib") << false << QString("Cannot load library nosuchlib: .*");
     QTest::newRow("call errorString() on QLibrary with no d-pointer (crashtest)") << (int)(Load | DontSetFileName) << QString() << false << QString("Unknown error");
-    QTest::newRow("bad resolve") << (int)Resolve << appDir + "/mylib" << false << QString("Cannot resolve symbol \"nosuchsymbol\" in \\S+: .*");
+    QTest::newRow("bad resolve") << (int)Resolve << appDir + "/mylib" << false << QString("Unknown error");
     QTest::newRow("good resolve") << (int)Resolve << appDir + "/mylib" << true << QString("Unknown error");
 
 #ifdef Q_OS_WIN
diff --git a/tests/auto/gui/text/qtextmarkdownimporter/data/fuzz20450.md b/tests/auto/gui/text/qtextmarkdownimporter/data/fuzz20450.md
new file mode 100644
index 0000000000..d7005cb01e
--- /dev/null
+++ b/tests/auto/gui/text/qtextmarkdownimporter/data/fuzz20450.md
@@ -0,0 +1,5 @@
+<t>ÿ
+* ÿ
+
+	ÿ
+* ÿ
\ No newline at end of file
diff --git a/tests/auto/gui/text/qtextmarkdownimporter/data/fuzz20580.md b/tests/auto/gui/text/qtextmarkdownimporter/data/fuzz20580.md
new file mode 100644
index 0000000000..22006f5876
--- /dev/null
+++ b/tests/auto/gui/text/qtextmarkdownimporter/data/fuzz20580.md
@@ -0,0 +1 @@
+|
--:|
<?`?><?|`
\ No newline at end of file
diff --git a/tests/auto/gui/text/qtextmarkdownimporter/qtextmarkdownimporter.pro b/tests/auto/gui/text/qtextmarkdownimporter/qtextmarkdownimporter.pro
index 7b7fb61244..f3818efbf7 100644
--- a/tests/auto/gui/text/qtextmarkdownimporter/qtextmarkdownimporter.pro
+++ b/tests/auto/gui/text/qtextmarkdownimporter/qtextmarkdownimporter.pro
@@ -5,5 +5,7 @@ SOURCES += tst_qtextmarkdownimporter.cpp
 TESTDATA += \
     data/thematicBreaks.md \
     data/headingBulletsContinuations.md \
+    data/fuzz20450.md \
+    data/fuzz20580.md \
 
 DEFINES += SRCDIR=\\\"$$PWD\\\"
diff --git a/tests/auto/gui/text/qtextmarkdownimporter/tst_qtextmarkdownimporter.cpp b/tests/auto/gui/text/qtextmarkdownimporter/tst_qtextmarkdownimporter.cpp
index 39a1370f6f..5eb04af696 100644
--- a/tests/auto/gui/text/qtextmarkdownimporter/tst_qtextmarkdownimporter.cpp
+++ b/tests/auto/gui/text/qtextmarkdownimporter/tst_qtextmarkdownimporter.cpp
@@ -57,6 +57,8 @@ private slots:
     void lists();
     void avoidBlankLineAtBeginning_data();
     void avoidBlankLineAtBeginning();
+    void pathological_data();
+    void pathological();
 };
 
 void tst_QTextMarkdownImporter::headingBulletsContinuations()
@@ -256,5 +258,27 @@ void tst_QTextMarkdownImporter::avoidBlankLineAtBeginning() // QTBUG-81060
     QCOMPARE(i, expectedNumberOfParagraphs);
 }
 
+void tst_QTextMarkdownImporter::pathological_data()
+{
+    QTest::addColumn<QString>("warning");
+    QTest::newRow("fuzz20450") << "attempted to insert into a list that no longer exists";
+    QTest::newRow("fuzz20580") << "";
+}
+
+void tst_QTextMarkdownImporter::pathological() // avoid crashing on crazy input
+{
+    QFETCH(QString, warning);
+    QString filename = QLatin1String("data/") + QTest::currentDataTag() + QLatin1String(".md");
+    QFile f(QFINDTESTDATA(filename));
+    QVERIFY(f.open(QFile::ReadOnly));
+#ifdef QT_NO_DEBUG
+    Q_UNUSED(warning)
+#else
+    if (!warning.isEmpty())
+        QTest::ignoreMessage(QtWarningMsg, warning.toLatin1());
+#endif
+    QTextDocument().setMarkdown(f.readAll());
+}
+
 QTEST_MAIN(tst_QTextMarkdownImporter)
 #include "tst_qtextmarkdownimporter.moc"
diff --git a/tests/auto/widgets/kernel/qwidget_window/BLACKLIST b/tests/auto/widgets/kernel/qwidget_window/BLACKLIST
index 39d7b695f6..d3bfaba433 100644
--- a/tests/auto/widgets/kernel/qwidget_window/BLACKLIST
+++ b/tests/auto/widgets/kernel/qwidget_window/BLACKLIST
@@ -2,7 +2,3 @@
 # QTBUG-66345
 opensuse-42.3
 ubuntu-16.04
-[setWindowState]
-ubuntu-18.04
-rhel-7.6
-
diff --git a/tests/auto/xml/dom/qdom/tst_qdom.cpp b/tests/auto/xml/dom/qdom/tst_qdom.cpp
index 99639df5b0..229d2ba6e5 100644
--- a/tests/auto/xml/dom/qdom/tst_qdom.cpp
+++ b/tests/auto/xml/dom/qdom/tst_qdom.cpp
@@ -38,6 +38,7 @@
 #include <QtTest/QtTest>
 #include <QtXml>
 #include <QVariant>
+#include <cmath>
 
 QT_FORWARD_DECLARE_CLASS(QDomDocument)
 QT_FORWARD_DECLARE_CLASS(QDomNode)
@@ -408,7 +409,9 @@ void tst_QDom::setGetAttributes()
     const int intVal = std::numeric_limits<int>::min();
     const uint uintVal = std::numeric_limits<uint>::max();
     const float floatVal = 0.1234f;
-    const double doubleVal = 0.1234;
+    const double doubleVal1 = 1./6.;
+    const double doubleVal2 = std::nextafter(doubleVal1, 1.);
+    const double doubleVal3 = std::nextafter(doubleVal2, 1.);
 
     rootNode.setAttribute("qstringVal", qstringVal);
     rootNode.setAttribute("qlonglongVal", qlonglongVal);
@@ -416,7 +419,9 @@ void tst_QDom::setGetAttributes()
     rootNode.setAttribute("intVal", intVal);
     rootNode.setAttribute("uintVal", uintVal);
     rootNode.setAttribute("floatVal", floatVal);
-    rootNode.setAttribute("doubleVal", doubleVal);
+    rootNode.setAttribute("doubleVal1", doubleVal1);
+    rootNode.setAttribute("doubleVal2", doubleVal2);
+    rootNode.setAttribute("doubleVal3", doubleVal3);
 
     QDomElement nsNode = doc.createElement("NS");
     rootNode.appendChild(nsNode);
@@ -426,7 +431,9 @@ void tst_QDom::setGetAttributes()
     nsNode.setAttributeNS("namespace", "intVal", intVal);
     nsNode.setAttributeNS("namespace", "uintVal", uintVal);
     nsNode.setAttributeNS("namespace", "floatVal", floatVal); // not available atm
-    nsNode.setAttributeNS("namespace", "doubleVal", doubleVal);
+    nsNode.setAttributeNS("namespace", "doubleVal1", doubleVal1);
+    nsNode.setAttributeNS("namespace", "doubleVal2", doubleVal2);
+    nsNode.setAttributeNS("namespace", "doubleVal3", doubleVal3);
 
     bool bOk;
     QCOMPARE(rootNode.attribute("qstringVal"), qstringVal);
@@ -440,8 +447,10 @@ void tst_QDom::setGetAttributes()
     QVERIFY(bOk);
     QCOMPARE(rootNode.attribute("floatVal").toFloat(&bOk), floatVal);
     QVERIFY(bOk);
-    QCOMPARE(rootNode.attribute("doubleVal").toDouble(&bOk), doubleVal);
-    QVERIFY(bOk);
+
+    QVERIFY(rootNode.attribute("doubleVal1").toDouble(&bOk) == doubleVal1 && bOk);
+    QVERIFY(rootNode.attribute("doubleVal2").toDouble(&bOk) == doubleVal2 && bOk);
+    QVERIFY(rootNode.attribute("doubleVal3").toDouble(&bOk) == doubleVal3 && bOk);
 
     QCOMPARE(nsNode.attributeNS("namespace", "qstringVal"), qstringVal);
     QCOMPARE(nsNode.attributeNS("namespace", "qlonglongVal").toLongLong(&bOk), qlonglongVal);
@@ -454,8 +463,9 @@ void tst_QDom::setGetAttributes()
     QVERIFY(bOk);
     QCOMPARE(nsNode.attributeNS("namespace", "floatVal").toFloat(&bOk), floatVal);
     QVERIFY(bOk);
-    QCOMPARE(nsNode.attributeNS("namespace", "doubleVal").toDouble(&bOk), doubleVal);
-    QVERIFY(bOk);
+    QVERIFY(nsNode.attributeNS("namespace", "doubleVal1").toDouble(&bOk) == doubleVal1 && bOk);
+    QVERIFY(nsNode.attributeNS("namespace", "doubleVal2").toDouble(&bOk) == doubleVal2 && bOk);
+    QVERIFY(nsNode.attributeNS("namespace", "doubleVal3").toDouble(&bOk) == doubleVal3 && bOk);
 
     QLocale::setDefault(oldLocale);
 }