QmlCompiler: Relax shadowing check

If we detect a property or method as potentially shadowed, we don't have
to abandon all hope. We can still retrieve it as untyped var. Since
there are a number of things we can do with untyped var, this may still
be useful.

In the same sense, we need to treat function calls as untyped when the
function in question can be shadowed. Calling functions with var
arguments and return types leads to some more interesting situations in
the call frame setup, so we fix that, too.

Task-number: QTBUG-112480
Change-Id: I238d1cf04951f390c73e14ed9e299f2aa72b68cb
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

1 files changed, 140 insertions, 18 deletions

diff --git a/src/qml/qml/qqml.cpp b/src/qml/qml/qqml.cpp
index bdebba53d0..4304934019 100644
--- a/src/qml/qml/qqml.cpp
+++ b/src/qml/qml/qqml.cpp
@@ -880,7 +880,8 @@ static bool inherits(const QQmlPropertyCache *descendent, const QQmlPropertyCach
 
 enum class ObjectPropertyResult { OK, NeedsInit, Deleted };
 
-static ObjectPropertyResult loadObjectProperty(
+template<bool StrictType = false>
+ObjectPropertyResult loadObjectProperty(
         QV4::Lookup *l, QObject *object, void *target, QQmlContextData *qmlContext)
 {
     QQmlData *qmlData = QQmlData::get(object);
@@ -890,8 +891,12 @@ static ObjectPropertyResult loadObjectProperty(
         return ObjectPropertyResult::Deleted;
     Q_ASSERT(!QQmlData::wasDeleted(object));
     const QQmlPropertyCache *propertyCache = l->qobjectLookup.propertyCache;
-    if (!inherits(qmlData->propertyCache.data(), propertyCache))
+    if (StrictType) {
+        if (qmlData->propertyCache.data() != propertyCache)
+            return ObjectPropertyResult::NeedsInit;
+    } else if (!inherits(qmlData->propertyCache.data(), propertyCache)) {
         return ObjectPropertyResult::NeedsInit;
+    }
     const QQmlPropertyData *property = l->qobjectLookup.propertyData;
 
     const int coreIndex = property->coreIndex();
@@ -930,7 +935,35 @@ static ObjectPropertyResult loadFallbackProperty(
     return ObjectPropertyResult::OK;
 }
 
-template<typename Op>
+ObjectPropertyResult loadObjectAsVariant(
+        QV4::Lookup *l, QObject *object, void *target, QQmlContextData *qmlContext)
+{
+    QVariant *variant = static_cast<QVariant *>(target);
+    const QMetaType propType = l->qobjectLookup.propertyData->propType();
+    if (propType == QMetaType::fromType<QVariant>())
+        return loadObjectProperty<true>(l, object, variant, qmlContext);
+
+    *variant = QVariant(propType);
+    return loadObjectProperty<true>(l, object, variant->data(), qmlContext);
+}
+
+ObjectPropertyResult loadFallbackAsVariant(
+        QV4::Lookup *l, QObject *object, void *target, QQmlContextData *qmlContext)
+{
+    const QMetaObject *metaObject
+            = reinterpret_cast<const QMetaObject *>(l->qobjectFallbackLookup.metaObject - 1);
+    Q_ASSERT(metaObject);
+
+    QVariant *variant = static_cast<QVariant *>(target);
+    const QMetaType propType = metaObject->property(l->qobjectFallbackLookup.coreIndex).metaType();
+    if (propType == QMetaType::fromType<QVariant>())
+        return loadFallbackProperty(l, object, variant, qmlContext);
+
+    *variant = QVariant(propType);
+    return loadFallbackProperty(l, object, variant->data(), qmlContext);
+}
+
+template<bool StrictType, typename Op>
 static ObjectPropertyResult changeObjectProperty(QV4::Lookup *l, QObject *object, Op op)
 {
     const QQmlData *qmlData = QQmlData::get(object);
@@ -939,24 +972,30 @@ static ObjectPropertyResult changeObjectProperty(QV4::Lookup *l, QObject *object
     if (qmlData->isQueuedForDeletion)
         return ObjectPropertyResult::Deleted;
     Q_ASSERT(!QQmlData::wasDeleted(object));
-    if (!inherits(qmlData->propertyCache.data(), l->qobjectLookup.propertyCache))
+    if (StrictType) {
+        if (qmlData->propertyCache.data() != l->qobjectLookup.propertyCache)
+            return ObjectPropertyResult::NeedsInit;
+    } else if (!inherits(qmlData->propertyCache.data(), l->qobjectLookup.propertyCache)) {
         return ObjectPropertyResult::NeedsInit;
+    }
     const QQmlPropertyData *property = l->qobjectLookup.propertyData;
     QQmlPropertyPrivate::removeBinding(object, QQmlPropertyIndex(property->coreIndex()));
     op(property);
     return ObjectPropertyResult::OK;
 }
 
+template<bool StrictType = false>
 static ObjectPropertyResult resetObjectProperty(QV4::Lookup *l, QObject *object)
 {
-    return changeObjectProperty(l, object, [&](const QQmlPropertyData *property) {
+    return changeObjectProperty<StrictType>(l, object, [&](const QQmlPropertyData *property) {
         property->resetProperty(object, {});
     });
 }
 
+template<bool StrictType = false>
 static ObjectPropertyResult storeObjectProperty(QV4::Lookup *l, QObject *object, void *value)
 {
-    return changeObjectProperty(l, object, [&](const QQmlPropertyData *property) {
+    return changeObjectProperty<StrictType>(l, object, [&](const QQmlPropertyData *property) {
         property->writeProperty(object, value, {});
     });
 }
@@ -1061,10 +1100,55 @@ static bool isTypeCompatible(QMetaType lookupType, QMetaType propertyType)
     return true;
 }
 
+static ObjectPropertyResult storeObjectAsVariant(
+        QV4::ExecutionEngine *v4, QV4::Lookup *l, QObject *object, void *value)
+{
+    QVariant *variant = static_cast<QVariant *>(value);
+    const QMetaType propType = l->qobjectLookup.propertyData->propType();
+    if (propType == QMetaType::fromType<QVariant>())
+        return storeObjectProperty<true>(l, object, variant);
+
+    if (!variant->isValid())
+        return resetObjectProperty<true>(l, object);
+
+    if (isTypeCompatible(variant->metaType(), propType))
+        return storeObjectProperty<true>(l, object, variant->data());
+
+    QVariant converted(propType);
+    v4->metaTypeFromJS(v4->fromVariant(*variant), propType, converted.data());
+    return storeObjectProperty<true>(l, object, converted.data());
+}
+
+static ObjectPropertyResult storeFallbackAsVariant(
+        QV4::ExecutionEngine *v4, QV4::Lookup *l, QObject *object, void *value)
+{
+    QVariant *variant = static_cast<QVariant *>(value);
+
+    const QMetaObject *metaObject
+            = reinterpret_cast<const QMetaObject *>(l->qobjectFallbackLookup.metaObject - 1);
+    Q_ASSERT(metaObject);
+
+    const QMetaType propType = metaObject->property(l->qobjectFallbackLookup.coreIndex).metaType();
+    if (propType == QMetaType::fromType<QVariant>())
+        return storeFallbackProperty(l, object, variant);
+
+    if (!propType.isValid())
+        return resetFallbackProperty(l, object);
+
+    if (isTypeCompatible(variant->metaType(), propType))
+        return storeFallbackProperty(l, object, variant->data());
+
+    QVariant converted(propType);
+    v4->metaTypeFromJS(v4->fromVariant(*variant), propType, converted.data());
+    return storeFallbackProperty(l, object, converted.data());
+}
+
 enum class ObjectLookupResult {
     Failure,
     Object,
-    Fallback
+    Fallback,
+    ObjectAsVariant,
+    FallbackAsVariant,
 };
 
 static ObjectLookupResult initObjectLookup(
@@ -1094,6 +1178,7 @@ static ObjectLookupResult initObjectLookup(
                     name.getPointer(), object, aotContext->qmlContext);
     }
 
+    const bool doVariantLookup = type == QMetaType::fromType<QVariant>();
     if (!property) {
         const QMetaObject *metaObject = object->metaObject();
         if (!metaObject)
@@ -1105,7 +1190,7 @@ static ObjectLookupResult initObjectLookup(
             return ObjectLookupResult::Failure;
 
         const QMetaProperty property = metaObject->property(coreIndex);
-        if (!isTypeCompatible(type, property.metaType()))
+        if (!doVariantLookup && !isTypeCompatible(type, property.metaType()))
             return ObjectLookupResult::Failure;
 
         l->releasePropertyCache();
@@ -1115,16 +1200,21 @@ static ObjectLookupResult initObjectLookup(
         l->qobjectFallbackLookup.notifyIndex =
                 QMetaObjectPrivate::signalIndex(property.notifySignal());
         l->qobjectFallbackLookup.isConstant = property.isConstant() ? 1 : 0;
-        return ObjectLookupResult::Fallback;
+        return doVariantLookup
+                ? ObjectLookupResult::FallbackAsVariant
+                : ObjectLookupResult::Fallback;
     }
 
-    if (!isTypeCompatible(type, property->propType()))
+    if (!doVariantLookup && !isTypeCompatible(type, property->propType()))
         return ObjectLookupResult::Failure;
 
     Q_ASSERT(ddata->propertyCache);
 
     QV4::setupQObjectLookup(l, ddata, property);
-    return ObjectLookupResult::Object;
+
+    return doVariantLookup
+            ? ObjectLookupResult::ObjectAsVariant
+            : ObjectLookupResult::Object;
 }
 
 static bool initValueLookup(QV4::Lookup *l, QV4::ExecutableCompilationUnit *compilationUnit,
@@ -1161,14 +1251,16 @@ bool AOTCompiledContext::captureLookup(uint index, QObject *object) const
 
     QV4::Lookup *l = compilationUnit->runtimeLookups + index;
     if (l->getter == QV4::QQmlTypeWrapper::lookupSingletonProperty
-            || l->getter == QV4::Lookup::getterQObject) {
+            || l->getter == QV4::Lookup::getterQObject
+            || l->getter == QV4::Lookup::getterQObjectAsVariant) {
         const QQmlPropertyData *property = l->qobjectLookup.propertyData;
         QQmlData::flushPendingBinding(object, property->coreIndex());
         captureObjectProperty(object, l->qobjectLookup.propertyCache, property, qmlContext);
         return true;
     }
 
-    if (l->getter == QV4::Lookup::getterFallback) {
+    if (l->getter == QV4::Lookup::getterFallback
+        || l->getter == QV4::Lookup::getterFallbackAsVariant) {
         const int coreIndex = l->qobjectFallbackLookup.coreIndex;
         QQmlData::flushPendingBinding(object, coreIndex);
         captureFallbackProperty(
@@ -1224,7 +1316,9 @@ QMetaType AOTCompiledContext::lookupResultMetaType(uint index) const
             || l->qmlContextPropertyGetter == QV4::QQmlContextWrapper::lookupContextObjectProperty
             || l->getter == QV4::QQmlTypeWrapper::lookupSingletonProperty
             || l->getter == QV4::Lookup::getterQObject
-            || l->setter == QV4::Lookup::setterQObject) {
+            || l->setter == QV4::Lookup::setterQObject
+            || l->getter == QV4::Lookup::getterQObjectAsVariant
+            || l->setter == QV4::Lookup::setterQObjectAsVariant) {
         return l->qobjectLookup.propertyData->propType();
     } else if (l->getter == QV4::QQmlValueTypeWrapper::lookupGetter) {
         return QMetaType(l->qgadgetLookup.metaType);
@@ -1237,6 +1331,8 @@ QMetaType AOTCompiledContext::lookupResultMetaType(uint index) const
         return QMetaType::fromType<QObject *>();
     } else if (l->getter == QV4::Lookup::getterFallback
                || l->setter == QV4::Lookup::setterFallback
+               || l->getter == QV4::Lookup::getterFallbackAsVariant
+               || l->setter == QV4::Lookup::setterFallbackAsVariant
                || l->qmlContextPropertyGetter
                     == QV4::QQmlContextWrapper::lookupScopeFallbackProperty) {
         const QMetaObject *metaObject
@@ -1272,33 +1368,37 @@ void AOTCompiledContext::storeNameSloppy(uint nameIndex, void *value, QMetaType
     l.forCall = false;
     ObjectPropertyResult storeResult = ObjectPropertyResult::NeedsInit;
     switch (initObjectLookup(this, &l, qmlScopeObject, QMetaType())) {
+    case ObjectLookupResult::ObjectAsVariant:
     case ObjectLookupResult::Object: {
         const QMetaType propType = l.qobjectLookup.propertyData->propType();
-        if (type == propType) {
+        if (isTypeCompatible(type, propType)) {
             storeResult = storeObjectProperty(&l, qmlScopeObject, value);
         } else if (isUndefined(value, type)) {
             storeResult = resetObjectProperty(&l, qmlScopeObject);
         } else {
             QVariant var(propType);
-            propType.convert(type, value, propType, var.data());
+            QV4::ExecutionEngine *v4 = engine->handle();
+            v4->metaTypeFromJS(v4->metaTypeToJS(type, value), propType, var.data());
             storeResult = storeObjectProperty(&l, qmlScopeObject, var.data());
         }
 
         l.qobjectLookup.propertyCache->release();
         break;
     }
+    case ObjectLookupResult::FallbackAsVariant:
     case ObjectLookupResult::Fallback: {
         const QMetaObject *metaObject
                 = reinterpret_cast<const QMetaObject *>(l.qobjectFallbackLookup.metaObject - 1);
         const QMetaType propType
                 = metaObject->property(l.qobjectFallbackLookup.coreIndex).metaType();
-        if (type == propType) {
+        if (isTypeCompatible(type, propType)) {
             storeResult = storeFallbackProperty(&l, qmlScopeObject, value);
         } else if (isUndefined(value, type)) {
             storeResult = resetFallbackProperty(&l, qmlScopeObject);
         } else {
             QVariant var(propType);
-            propType.convert(type, value, propType, var.data());
+            QV4::ExecutionEngine *v4 = engine->handle();
+            v4->metaTypeFromJS(v4->metaTypeToJS(type, value), propType, var.data());
             storeResult = storeFallbackProperty(&l, qmlScopeObject, var.data());
         }
         break;
@@ -1574,9 +1674,11 @@ void AOTCompiledContext::initLoadScopeObjectPropertyLookup(uint index, QMetaType
     }
 
     switch (initObjectLookup(this, l, qmlScopeObject, type)) {
+    case ObjectLookupResult::ObjectAsVariant:
     case ObjectLookupResult::Object:
         l->qmlContextPropertyGetter = QV4::QQmlContextWrapper::lookupScopeObjectProperty;
         break;
+    case ObjectLookupResult::FallbackAsVariant:
     case ObjectLookupResult::Fallback:
         l->qmlContextPropertyGetter = QV4::QQmlContextWrapper::lookupScopeFallbackProperty;
         break;
@@ -1742,6 +1844,10 @@ bool AOTCompiledContext::getObjectLookup(uint index, QObject *object, void *targ
         result = loadObjectProperty(l, object, target, qmlContext);
     else if (l->getter == QV4::Lookup::getterFallback)
         result = loadFallbackProperty(l, object, target, qmlContext);
+    else if (l->getter == QV4::Lookup::getterQObjectAsVariant)
+        result = loadObjectAsVariant(l, object, target, qmlContext);
+    else if (l->getter == QV4::Lookup::getterFallbackAsVariant)
+        result = loadFallbackAsVariant(l, object, target, qmlContext);
     else
         return false;
 
@@ -1768,9 +1874,15 @@ void AOTCompiledContext::initGetObjectLookup(uint index, QObject *object, QMetaT
         case ObjectLookupResult::Object:
             l->getter = QV4::Lookup::getterQObject;
             break;
+        case ObjectLookupResult::ObjectAsVariant:
+            l->getter = QV4::Lookup::getterQObjectAsVariant;
+            break;
         case ObjectLookupResult::Fallback:
             l->getter = QV4::Lookup::getterFallback;
             break;
+        case ObjectLookupResult::FallbackAsVariant:
+            l->getter = QV4::Lookup::getterFallbackAsVariant;
+            break;
         case ObjectLookupResult::Failure:
             engine->handle()->throwTypeError();
             break;
@@ -1884,6 +1996,10 @@ bool AOTCompiledContext::setObjectLookup(uint index, QObject *object, void *valu
         result = storeObjectProperty(l, object, value);
     else if (l->setter == QV4::Lookup::setterFallback)
         result = storeFallbackProperty(l, object, value);
+    else if (l->setter == QV4::Lookup::setterQObjectAsVariant)
+        result = storeObjectAsVariant(engine->handle(), l, object, value);
+    else if (l->setter == QV4::Lookup::setterFallbackAsVariant)
+        result = storeFallbackAsVariant(engine->handle(), l, object, value);
     else
         return false;
 
@@ -1910,9 +2026,15 @@ void AOTCompiledContext::initSetObjectLookup(uint index, QObject *object, QMetaT
         case ObjectLookupResult::Object:
             l->setter = QV4::Lookup::setterQObject;
             break;
+        case ObjectLookupResult::ObjectAsVariant:
+            l->setter = QV4::Lookup::setterQObjectAsVariant;
+            break;
         case ObjectLookupResult::Fallback:
             l->setter = QV4::Lookup::setterFallback;
             break;
+        case ObjectLookupResult::FallbackAsVariant:
+            l->setter = QV4::Lookup::setterFallbackAsVariant;
+            break;
         case ObjectLookupResult::Failure:
             engine->handle()->throwTypeError();
             break;