11 files changed, 84 insertions, 50 deletions
diff --git a/src/qml/jsruntime/qv4context.cpp b/src/qml/jsruntime/qv4context.cpp
index 1a1efc0b4c..56701457e4 100644
--- a/src/qml/jsruntime/qv4context.cpp
+++ b/src/qml/jsruntime/qv4context.cpp
@@ -363,6 +363,7 @@ void ExecutionContext::mark()
 
 void ExecutionContext::setProperty(String *name, const Value& value)
 {
+    Scope scope(this);
     for (ExecutionContext *ctx = this; ctx; ctx = ctx->outer) {
         if (ctx->type == Type_WithContext) {
             Object *w = static_cast<WithContext *>(ctx)->withObject;
@@ -398,8 +399,10 @@ void ExecutionContext::setProperty(String *name, const Value& value)
             }
         }
     }
-    if (strictMode || name->isEqualTo(engine->id_this))
-        throwReferenceError(Value::fromString(name));
+    if (strictMode || name->isEqualTo(engine->id_this)) {
+        Scoped<String> n(scope, name);
+        throwReferenceError(n);
+    }
     engine->globalObject->put(name, value);
 }
 
@@ -463,7 +466,8 @@ ReturnedValue ExecutionContext::getProperty(String *name)
                 return v.asReturnedValue();
         }
     }
-    throwReferenceError(Value::fromString(name));
+    Scoped<String> n(scope, name);
+    throwReferenceError(n);
     return Value::undefinedValue().asReturnedValue();
 }
 
@@ -595,75 +599,92 @@ ReturnedValue ExecutionContext::getPropertyAndBase(String *name, Object **base)
                 return v.asReturnedValue();
         }
     }
-    throwReferenceError(Value::fromString(name));
+    Scoped<String> n(scope, name);
+    throwReferenceError(n);
     return Value::undefinedValue().asReturnedValue();
 }
 
 
-void ExecutionContext::throwError(const Value &value)
+void ExecutionContext::throwError(const ValueRef value)
 {
-    Scope scope(this);
-    ScopedValue v(scope, value);
-    __qmljs_throw(this, v);
+    __qmljs_throw(this, value);
 }
 
 void ExecutionContext::throwError(const QString &message)
 {
-    Value v = Value::fromString(this, message);
-    throwError(Value::fromObject(engine->newErrorObject(v)));
+    Scope scope(this);
+    ScopedValue v(scope, Value::fromString(this, message));
+    v = engine->newErrorObject(v);
+    throwError(v);
 }
 
 void ExecutionContext::throwSyntaxError(const QString &message, const QString &fileName, int line, int column)
 {
-    Object *error = engine->newSyntaxErrorObject(message, fileName, line, column);
-    throwError(Value::fromObject(error));
+    Scope scope(this);
+    Scoped<Object> error(scope, engine->newSyntaxErrorObject(message, fileName, line, column));
+    throwError(error);
 }
 
 void ExecutionContext::throwSyntaxError(const QString &message)
 {
-    Object *error = engine->newSyntaxErrorObject(message);
-    throwError(Value::fromObject(error));
+    Scope scope(this);
+    Scoped<Object> error(scope, engine->newSyntaxErrorObject(message));
+    throwError(error);
 }
 
 void ExecutionContext::throwTypeError()
 {
-    throwError(Value::fromObject(engine->newTypeErrorObject(QStringLiteral("Type error"))));
+    Scope scope(this);
+    Scoped<Object> error(scope, engine->newTypeErrorObject(QStringLiteral("Type error")));
+    throwError(error);
 }
 
 void ExecutionContext::throwTypeError(const QString &message)
 {
-    throwError(Value::fromObject(engine->newTypeErrorObject(message)));
+    Scope scope(this);
+    Scoped<Object> error(scope, engine->newTypeErrorObject(message));
+    throwError(error);
 }
 
 void ExecutionContext::throwUnimplemented(const QString &message)
 {
-    Value v = Value::fromString(this, QStringLiteral("Unimplemented ") + message);
-    throwError(Value::fromObject(engine->newErrorObject(v)));
+    Scope scope(this);
+    ScopedValue v(scope, Value::fromString(this, QStringLiteral("Unimplemented ") + message));
+    v = engine->newErrorObject(v);
+    throwError(v);
 }
 
-void ExecutionContext::throwReferenceError(Value value)
+void ExecutionContext::throwReferenceError(const ValueRef value)
 {
-    String *s = value.toString(this);
+    Scope scope(this);
+    Scoped<String> s(scope, value->toString(this));
     QString msg = s->toQString() + QStringLiteral(" is not defined");
-    throwError(Value::fromObject(engine->newReferenceErrorObject(msg)));
+    Scoped<Object> error(scope, engine->newReferenceErrorObject(msg));
+    throwError(error);
 }
 
 void ExecutionContext::throwReferenceError(const QString &message, const QString &fileName, int line, int column)
 {
+    Scope scope(this);
     QString msg = message + QStringLiteral(" is not defined");
-    throwError(Value::fromObject(engine->newReferenceErrorObject(msg, fileName, line, column)));
+    Scoped<Object> error(scope, engine->newReferenceErrorObject(msg, fileName, line, column));
+    throwError(error);
 }
 
 void ExecutionContext::throwRangeError(Value value)
 {
-    String *s = value.toString(this);
+    Scope scope(this);
+    Scoped<String> s(scope, value.toString(this));
     QString msg = s->toQString() + QStringLiteral(" out of range");
-    throwError(Value::fromObject(engine->newRangeErrorObject(msg)));
+    Scoped<Object> error(scope, engine->newRangeErrorObject(msg));
+    throwError(error);
 }
 
 void ExecutionContext::throwURIError(Value msg)
 {
-    throwError(Value::fromObject(engine->newURIErrorObject(msg)));
+    Scope scope(this);
+    Scoped<Object> error(scope, engine->newURIErrorObject(msg));
+    throwError(error);
 }
 
 void SimpleCallContext::initSimpleCallContext(ExecutionEngine *engine)
diff --git a/src/qml/jsruntime/qv4context_p.h b/src/qml/jsruntime/qv4context_p.h
index 8ebffea981..0c3b189401 100644
--- a/src/qml/jsruntime/qv4context_p.h
+++ b/src/qml/jsruntime/qv4context_p.h
@@ -54,6 +54,7 @@ struct ExecutionEngine;
 struct DeclarativeEnvironment;
 struct Lookup;
 struct Function;
+struct ValueRef;
 
 namespace CompiledData {
 struct CompilationUnit;
@@ -129,13 +130,13 @@ struct Q_QML_EXPORT ExecutionContext
 
     void createMutableBinding(String *name, bool deletable);
 
-    void Q_NORETURN throwError(const Value &value);
+    void Q_NORETURN throwError(const QV4::ValueRef value);
     void Q_NORETURN throwError(const QString &message);
     void Q_NORETURN throwSyntaxError(const QString &message);
     void Q_NORETURN throwSyntaxError(const QString &message, const QString &fileName, int line, int column);
     void Q_NORETURN throwTypeError();
     void Q_NORETURN throwTypeError(const QString &message);
-    void Q_NORETURN throwReferenceError(Value value);
+    void Q_NORETURN throwReferenceError(const ValueRef value);
     void Q_NORETURN throwReferenceError(const QString &value, const QString &fileName, int line, int column);
     void Q_NORETURN throwRangeError(Value value);
     void Q_NORETURN throwURIError(Value msg);
diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index 875ab84cf5..0187099f62 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -375,10 +375,10 @@ String *ExecutionEngine::newIdentifier(const QString &text)
     return identifierTable->insertString(text);
 }
 
-Object *ExecutionEngine::newStringObject(const Value &value)
+Returned<Object> *ExecutionEngine::newStringObject(const Value &value)
 {
     StringObject *object = new (memoryManager) StringObject(this, value);
-    return object;
+    return object->asReturned<Object>();
 }
 
 Returned<Object> *ExecutionEngine::newNumberObject(const Value &value)
@@ -455,20 +455,22 @@ Returned<RegExpObject> *ExecutionEngine::newRegExpObject(const QRegExp &re)
     return object->asReturned<RegExpObject>();
 }
 
-Object *ExecutionEngine::newErrorObject(const Value &value)
+Returned<Object> *ExecutionEngine::newErrorObject(const Value &value)
 {
     ErrorObject *object = new (memoryManager) ErrorObject(errorClass, value);
-    return object;
+    return object->asReturned<Object>();
 }
 
-Object *ExecutionEngine::newSyntaxErrorObject(const QString &message)
+Returned<Object> *ExecutionEngine::newSyntaxErrorObject(const QString &message)
 {
-    return new (memoryManager) SyntaxErrorObject(this, Value::fromString(this, message));
+    Object *error = new (memoryManager) SyntaxErrorObject(this, Value::fromString(this, message));
+    return error->asReturned<Object>();
 }
 
-Object *ExecutionEngine::newSyntaxErrorObject(const QString &message, const QString &fileName, int line, int column)
+Returned<Object> *ExecutionEngine::newSyntaxErrorObject(const QString &message, const QString &fileName, int line, int column)
 {
-    return new (memoryManager) SyntaxErrorObject(this, message, fileName, line, column);
+    Object *error = new (memoryManager) SyntaxErrorObject(this, message, fileName, line, column);
+    return error->asReturned<Object>();
 }
 
 
diff --git a/src/qml/jsruntime/qv4engine_p.h b/src/qml/jsruntime/qv4engine_p.h
index a59a837499..5ef7d08a4a 100644
--- a/src/qml/jsruntime/qv4engine_p.h
+++ b/src/qml/jsruntime/qv4engine_p.h
@@ -270,7 +270,7 @@ struct Q_QML_EXPORT ExecutionEngine
     String *newString(const QString &s);
     String *newIdentifier(const QString &text);
 
-    Object *newStringObject(const Value &value);
+    Returned<Object> *newStringObject(const Value &value);
     Returned<Object> *newNumberObject(const Value &value);
     Returned<Object> *newBooleanObject(const Value &value);
 
@@ -285,9 +285,9 @@ struct Q_QML_EXPORT ExecutionEngine
     Returned<RegExpObject> *newRegExpObject(RegExp* re, bool global);
     Returned<RegExpObject> *newRegExpObject(const QRegExp &re);
 
-    Object *newErrorObject(const Value &value);
-    Object *newSyntaxErrorObject(const QString &message, const QString &fileName, int line, int column);
-    Object *newSyntaxErrorObject(const QString &message);
+    Returned<Object> *newErrorObject(const Value &value);
+    Returned<Object> *newSyntaxErrorObject(const QString &message, const QString &fileName, int line, int column);
+    Returned<Object> *newSyntaxErrorObject(const QString &message);
     Object *newReferenceErrorObject(const QString &message);
     Object *newReferenceErrorObject(const QString &message, const QString &fileName, int lineNumber, int columnNumber);
     Object *newTypeErrorObject(const QString &message);
diff --git a/src/qml/jsruntime/qv4errorobject.cpp b/src/qml/jsruntime/qv4errorobject.cpp
index 7c75d1162a..987d5083fa 100644
--- a/src/qml/jsruntime/qv4errorobject.cpp
+++ b/src/qml/jsruntime/qv4errorobject.cpp
@@ -242,7 +242,7 @@ ErrorCtor::ErrorCtor(ExecutionContext *scope, String *name)
 
 ReturnedValue ErrorCtor::construct(Managed *m, CallData *callData)
 {
-    return Value::fromObject(m->engine()->newErrorObject(callData->argc ? callData->args[0] : Value::undefinedValue())).asReturnedValue();
+    return Encode(m->engine()->newErrorObject(callData->argc ? callData->args[0] : Value::undefinedValue()));
 }
 
 ReturnedValue ErrorCtor::call(Managed *that, CallData *callData)
diff --git a/src/qml/jsruntime/qv4lookup.cpp b/src/qml/jsruntime/qv4lookup.cpp
index a4116b049e..a844a25008 100644
--- a/src/qml/jsruntime/qv4lookup.cpp
+++ b/src/qml/jsruntime/qv4lookup.cpp
@@ -334,7 +334,9 @@ ReturnedValue Lookup::globalGetterGeneric(Lookup *l, ExecutionContext *ctx)
             return o->getValue(p, attrs);
         }
     }
-    ctx->throwReferenceError(Value::fromString(l->name));
+    Scope scope(ctx);
+    Scoped<String> n(scope, l->name);
+    ctx->throwReferenceError(n);
 }
 
 ReturnedValue Lookup::globalGetter0(Lookup *l, ExecutionContext *ctx)
diff --git a/src/qml/jsruntime/qv4runtime.cpp b/src/qml/jsruntime/qv4runtime.cpp
index 7af8b21cc5..d98087b6a4 100644
--- a/src/qml/jsruntime/qv4runtime.cpp
+++ b/src/qml/jsruntime/qv4runtime.cpp
@@ -607,7 +607,7 @@ Returned<Object> *__qmljs_convert_to_object(ExecutionContext *ctx, const ValueRe
     case Value::Boolean_Type:
         return ctx->engine->newBooleanObject(*value);
     case Value::String_Type:
-        return ctx->engine->newStringObject(*value)->asReturned<Object>();
+        return ctx->engine->newStringObject(*value);
         break;
     case Value::Object_Type:
         Q_UNREACHABLE();
diff --git a/src/qml/jsruntime/qv4scopedvalue_p.h b/src/qml/jsruntime/qv4scopedvalue_p.h
index eed49bfe1f..4bbd3303ee 100644
--- a/src/qml/jsruntime/qv4scopedvalue_p.h
+++ b/src/qml/jsruntime/qv4scopedvalue_p.h
@@ -142,7 +142,7 @@ struct ScopedValue
     ScopedValue(const Scope &scope, Returned<T> *t)
     {
         ptr = scope.engine->jsStackTop++;
-        ptr->val = T::toValue(t->getPointer());
+        *ptr = T::toValue(t->getPointer());
 #ifndef QT_NO_DEBUG
         ++scope.size;
 #endif
@@ -159,8 +159,8 @@ struct ScopedValue
     }
 
     template<typename T>
-    ScopedValue &operator=(const Returned<T> *t) {
-        ptr->val = T::toValue(t->getPointer());
+    ScopedValue &operator=(Returned<T> *t) {
+        *ptr = T::toValue(t->getPointer());
         return *this;
     }
 
@@ -331,6 +331,9 @@ struct ScopedCallData {
 struct ValueRef {
     ValueRef(const ScopedValue &v)
         : ptr(v.ptr) {}
+    template <typename T>
+    ValueRef(const Scoped<T> &v)
+        : ptr(v.ptr) {}
     ValueRef(const PersistentValue &v)
         : ptr(&v.d->value) {}
     ValueRef(PersistentValuePrivate *p)
diff --git a/src/qml/jsruntime/qv4script.cpp b/src/qml/jsruntime/qv4script.cpp
index e3c9505ab7..1834e28be6 100644
--- a/src/qml/jsruntime/qv4script.cpp
+++ b/src/qml/jsruntime/qv4script.cpp
@@ -153,6 +153,7 @@ void Script::parse()
     parsed = true;
 
     ExecutionEngine *v4 = scope->engine;
+    Scope valueScope(v4);
 
     MemoryManager::GCBlocker gcBlocker(v4->memoryManager);
 
@@ -199,9 +200,11 @@ void Script::parse()
         compilationUnitHolder = Value::fromObject(new (v4->memoryManager) CompilationUnitHolder(v4, compilationUnit));
     }
 
-    if (!vmFunction)
+    if (!vmFunction) {
         // ### FIX file/line number
-        v4->current->throwError(QV4::Value::fromObject(v4->newSyntaxErrorObject("Syntax error")));
+        Scoped<Object> error(valueScope, v4->newSyntaxErrorObject("Syntax error"));
+        v4->current->throwError(error);
+    }
 }
 
 ReturnedValue Script::run()
diff --git a/src/qml/jsruntime/qv4string.cpp b/src/qml/jsruntime/qv4string.cpp
index 2b2eda7c8c..d0f3a196b7 100644
--- a/src/qml/jsruntime/qv4string.cpp
+++ b/src/qml/jsruntime/qv4string.cpp
@@ -173,15 +173,17 @@ ReturnedValue String::getIndexed(Managed *m, uint index, bool *hasProperty)
 
 void String::put(Managed *m, String *name, const Value &value)
 {
+    Scope scope(m->engine());
     String *that = static_cast<String *>(m);
-    Object *o = that->engine()->newStringObject(Value::fromString(that));
+    Scoped<Object> o(scope, that->engine()->newStringObject(Value::fromString(that)));
     o->put(name, value);
 }
 
 void String::putIndexed(Managed *m, uint index, const Value &value)
 {
+    Scope scope(m->engine());
     String *that = static_cast<String *>(m);
-    Object *o = m->engine()->newStringObject(Value::fromString(that));
+    Scoped<Object> o(scope, that->engine()->newStringObject(Value::fromString(that)));
     o->putIndexed(index, value);
 }
 
diff --git a/src/qml/jsruntime/qv4stringobject.cpp b/src/qml/jsruntime/qv4stringobject.cpp
index dfdb639d1e..2223432ec9 100644
--- a/src/qml/jsruntime/qv4stringobject.cpp
+++ b/src/qml/jsruntime/qv4stringobject.cpp
@@ -167,7 +167,7 @@ ReturnedValue StringCtor::construct(Managed *m, CallData *callData)
         value = Value::fromString(callData->args[0].toString(m->engine()->current));
     else
         value = Value::fromString(m->engine()->current, QString());
-    return Value::fromObject(m->engine()->newStringObject(value)).asReturnedValue();
+    return Encode(m->engine()->newStringObject(value));
 }
 
 ReturnedValue StringCtor::call(Managed *m, CallData *callData)