Resolve member expressions of QObject members

...when the base is a QObject property itself or an ID referenced object.

This patch resolves for example the width property in a parent.width expression
to be a per-index lookup at run-time. That requires the base ("parent") however
to be a final property or come from an object where expected revision is known, i.e.
a QML imported object (scope or context).

Change-Id: Iaa1f57ace452da5e059c1d4e63b52b316e1a6b08
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

5 files changed, 62 insertions, 9 deletions

diff --git a/src/qml/compiler/qqmlcodegenerator.cpp b/src/qml/compiler/qqmlcodegenerator.cpp
index 7b1984fce0..5fefa61a7a 100644
--- a/src/qml/compiler/qqmlcodegenerator.cpp
+++ b/src/qml/compiler/qqmlcodegenerator.cpp
@@ -1198,8 +1198,9 @@ int QmlUnitGenerator::getStringId(const QString &str) const
     return jsUnitGenerator->getStringId(str);
 }
 
-JSCodeGen::JSCodeGen(const QString &fileName, const QString &sourceCode, V4IR::Module *jsModule, Engine *jsEngine, AST::UiProgram *qmlRoot, QQmlTypeNameCache *imports)
+JSCodeGen::JSCodeGen(QQmlEnginePrivate *enginePrivate, const QString &fileName, const QString &sourceCode, V4IR::Module *jsModule, Engine *jsEngine, AST::UiProgram *qmlRoot, QQmlTypeNameCache *imports)
     : QQmlJS::Codegen(/*strict mode*/false)
+    , engine(enginePrivate)
     , sourceCode(sourceCode)
     , jsEngine(jsEngine)
     , qmlRoot(qmlRoot)
@@ -1283,14 +1284,16 @@ QVector<int> JSCodeGen::generateJSCodeForFunctionsAndBindings(const QList<AST::N
     return runtimeFunctionIndices;
 }
 
-static QQmlPropertyData *lookupQmlCompliantProperty(QQmlPropertyCache *cache, const QString &name, bool *propertyExistsButForceNameLookup)
+static QQmlPropertyData *lookupQmlCompliantProperty(QQmlPropertyCache *cache, const QString &name, bool *propertyExistsButForceNameLookup = 0)
 {
-    *propertyExistsButForceNameLookup = false;
+    if (propertyExistsButForceNameLookup)
+        *propertyExistsButForceNameLookup = false;
     QQmlPropertyData *pd = cache->property(name, /*object*/0, /*context*/0);
 
     // Q_INVOKABLEs can't be FINAL, so we have to look them up at run-time
     if (pd && pd->isFunction()) {
-        *propertyExistsButForceNameLookup = true;
+        if (propertyExistsButForceNameLookup)
+            *propertyExistsButForceNameLookup = true;
         pd = 0;
     }
 
@@ -1300,6 +1303,49 @@ static QQmlPropertyData *lookupQmlCompliantProperty(QQmlPropertyCache *cache, co
     return pd;
 }
 
+V4IR::Expr *JSCodeGen::member(V4IR::Expr *base, const QString *name)
+{
+    V4IR::Member *baseAsMember = base->asMember();
+    if (baseAsMember) {
+        QQmlPropertyCache *cache = 0;
+
+        if (baseAsMember->type == V4IR::Member::MemberOfQObject
+            && baseAsMember->property->isQObject()) {
+
+            bool propertySuitable = baseAsMember->property->isFinal();
+
+            if (!propertySuitable) {
+                // Properties of the scope or context object do not need to be final, as we
+                // intend to find the version of a property available at compile time, not at run-time.
+                if (V4IR::Name *baseName = baseAsMember->base->asName())
+                    propertySuitable = baseName->builtin == V4IR::Name::builtin_qml_scope_object || baseName->builtin == V4IR::Name::builtin_qml_context_object;
+            }
+
+            // Check if it's suitable for caching
+            if (propertySuitable)
+                cache = engine->propertyCacheForType(baseAsMember->property->propType);
+        } else if (baseAsMember->type == V4IR::Member::MemberByObjectId) {
+            // Similarly, properties of an id referenced object also don't need to be final, because
+            // we intend to find the version of a property available at compile time, not at run-time.
+            foreach (const IdMapping &mapping, _idObjects) {
+                if (baseAsMember->objectId == mapping.idIndex) {
+                    cache = mapping.type;
+                    break;
+                }
+            }
+        }
+
+        if (cache) {
+            if (QQmlPropertyData *pd = lookupQmlCompliantProperty(cache, *name)) {
+                const unsigned baseTemp = _block->newTemp();
+                move(_block->TEMP(baseTemp), base);
+                return _block->QML_QOBJECT_PROPERTY(_block->TEMP(baseTemp), name, pd);
+            }
+        }
+    }
+    return QQmlJS::Codegen::member(base, name);
+}
+
 V4IR::Expr *JSCodeGen::fallbackNameLookup(const QString &name, int line, int col)
 {
     V4IR::Expr *result = 0;
diff --git a/src/qml/compiler/qqmlcodegenerator_p.h b/src/qml/compiler/qqmlcodegenerator_p.h
index 43bc979205..d077bff6db 100644
--- a/src/qml/compiler/qqmlcodegenerator_p.h
+++ b/src/qml/compiler/qqmlcodegenerator_p.h
@@ -347,13 +347,14 @@ private:
 
 struct Q_QML_EXPORT JSCodeGen : public QQmlJS::Codegen
 {
-    JSCodeGen(const QString &fileName, const QString &sourceCode, V4IR::Module *jsModule,
+    JSCodeGen(QQmlEnginePrivate *enginePrivate, const QString &fileName, const QString &sourceCode, V4IR::Module *jsModule,
               QQmlJS::Engine *jsEngine, AST::UiProgram *qmlRoot, QQmlTypeNameCache *imports);
 
     struct IdMapping
     {
         QString name;
         int idIndex;
+        QQmlPropertyCache *type;
     };
     typedef QVector<IdMapping> ObjectIdMapping;
 
@@ -363,10 +364,14 @@ struct Q_QML_EXPORT JSCodeGen : public QQmlJS::Codegen
     // Returns mapping from input functions to index in V4IR::Module::functions / compiledData->runtimeFunctions
     QVector<int> generateJSCodeForFunctionsAndBindings(const QList<AST::Node*> &functions);
 
+    // Resolve QObject members with the help of QQmlEngine's meta type registry
+    virtual V4IR::Expr *member(V4IR::Expr *base, const QString *name);
+
 protected:
     virtual V4IR::Expr *fallbackNameLookup(const QString &name, int line, int col);
 
 private:
+    QQmlEnginePrivate *engine;
     QString sourceCode;
     QQmlJS::Engine *jsEngine; // needed for memory pool
     AST::UiProgram *qmlRoot;
diff --git a/src/qml/compiler/qv4codegen_p.h b/src/qml/compiler/qv4codegen_p.h
index f5cdd27efa..490e469dc7 100644
--- a/src/qml/compiler/qv4codegen_p.h
+++ b/src/qml/compiler/qv4codegen_p.h
@@ -291,7 +291,7 @@ protected:
         _exceptionHandlers.pop();
     }
 
-    V4IR::Expr *member(V4IR::Expr *base, const QString *name);
+    virtual V4IR::Expr *member(V4IR::Expr *base, const QString *name); // Re-implemented by QML to resolve QObject property members
     V4IR::Expr *subscript(V4IR::Expr *base, V4IR::Expr *index);
     V4IR::Expr *argument(V4IR::Expr *expr);
     V4IR::Expr *reference(V4IR::Expr *expr);
diff --git a/src/qml/qml/qqmlcompiler.cpp b/src/qml/qml/qqmlcompiler.cpp
index 3f57d7c2ef..fc8570d128 100644
--- a/src/qml/qml/qqmlcompiler.cpp
+++ b/src/qml/qml/qqmlcompiler.cpp
@@ -3657,7 +3657,7 @@ bool QQmlCompiler::completeComponentBuild()
         const QString &sourceCode = jsEngine->code();
         AST::UiProgram *qmlRoot = parser.qmlRoot();
 
-        JSCodeGen jsCodeGen(unit->finalUrlString(), sourceCode, jsModule.data(), jsEngine, qmlRoot, output->importCache);
+        JSCodeGen jsCodeGen(enginePrivate, unit->finalUrlString(), sourceCode, jsModule.data(), jsEngine, qmlRoot, output->importCache);
 
         JSCodeGen::ObjectIdMapping idMapping;
         if (compileState->ids.count() > 0) {
@@ -3666,6 +3666,7 @@ bool QQmlCompiler::completeComponentBuild()
                 JSCodeGen::IdMapping m;
                 m.name = o->id;
                 m.idIndex = o->idIndex;
+                m.type = o->metatype;
                 idMapping << m;
             }
         }
diff --git a/src/qml/qml/qqmltypeloader.cpp b/src/qml/qml/qqmltypeloader.cpp
index b3bc5eb4a1..8d9c4ef2fe 100644
--- a/src/qml/qml/qqmltypeloader.cpp
+++ b/src/qml/qml/qqmltypeloader.cpp
@@ -2307,6 +2307,7 @@ void QQmlTypeData::compile()
         m_compiledData->importCache->addref();
 
         QQmlEngine *engine = typeLoader()->engine();
+        QQmlEnginePrivate *enginePrivate = QQmlEnginePrivate::get(engine);
 
         for (QHash<int, TypeReference>::ConstIterator resolvedType = m_resolvedTypes.constBegin(), end = m_resolvedTypes.constEnd();
              resolvedType != end; ++resolvedType) {
@@ -2357,7 +2358,7 @@ void QQmlTypeData::compile()
 
         // Compile JS binding expressions and signal handlers
 
-        JSCodeGen jsCodeGen(finalUrlString(), parsedQML->code, &parsedQML->jsModule, &parsedQML->jsParserEngine, parsedQML->program, m_compiledData->importCache);
+        JSCodeGen jsCodeGen(enginePrivate, finalUrlString(), parsedQML->code, &parsedQML->jsModule, &parsedQML->jsParserEngine, parsedQML->program, m_compiledData->importCache);
         const QVector<int> runtimeFunctionIndices = jsCodeGen.generateJSCodeForFunctionsAndBindings(parsedQML->functions);
 
         QV4::ExecutionEngine *v4 = QV8Engine::getV4(m_typeLoader->engine());
@@ -2389,7 +2390,7 @@ void QQmlTypeData::compile()
         m_compiledData->datas.reserve(qmlUnit->nObjects);
         m_compiledData->propertyCaches.reserve(qmlUnit->nObjects);
 
-        QQmlPropertyCacheCreator propertyCacheBuilder(QQmlEnginePrivate::get(m_typeLoader->engine()),
+        QQmlPropertyCacheCreator propertyCacheBuilder(enginePrivate,
                                                       qmlUnit, m_compiledData->url,
                                                       &m_imports, &m_compiledData->resolvedTypes);