Avoid creating a CallContext for simple functions

This cuts out quite a bit of overhead when entering
and leaving functions.

Change-Id: I32670c98a4087ea3b2d45853d9cabff9066399e8
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

15 files changed, 109 insertions, 77 deletions

diff --git a/src/qml/compiler/qv4codegen.cpp b/src/qml/compiler/qv4codegen.cpp
index 52e908d4f3..2a474eaad5 100644
--- a/src/qml/compiler/qv4codegen.cpp
+++ b/src/qml/compiler/qv4codegen.cpp
@@ -1263,6 +1263,29 @@ Codegen::Reference Codegen::referenceForName(const QString &name, bool isLhs)
     int scope = 0;
     Context *c = _context;
 
+    // skip the innermost context if it's simple (as the runtime won't
+    // create a context for it
+    if (c->canUseSimpleCall()) {
+        Context::Member m = c->findMember(name);
+        if (m.type != Context::UndefinedMember) {
+            Q_ASSERT((!m.canEscape));
+            Reference r = Reference::fromStackSlot(this, m.index, true /*isLocal*/);
+            if (name == QLatin1String("arguments") || name == QLatin1String("eval")) {
+                r.isArgOrEval = true;
+                if (isLhs && c->isStrict)
+                    // ### add correct source location
+                    throwSyntaxError(SourceLocation(), QStringLiteral("Variable name may not be eval or arguments in strict mode"));
+            }
+            return r;
+        }
+        const int argIdx = c->findArgument(name);
+        if (argIdx != -1) {
+            Q_ASSERT(!c->argumentsCanEscape && c->usesArgumentsObject != Context::ArgumentsObjectUsed);
+            return Reference::fromArgument(this, argIdx);
+        }
+        c = c->parent;
+    }
+
     while (c->parent) {
         if (c->forceLookupByName() || (c->isNamedFunctionExpression && c->name == name))
             goto loadByName;
@@ -1771,8 +1794,8 @@ int Codegen::defineFunction(const QString &name, AST::Node *ast,
     savedBytecodeGenerator = bytecodeGenerator;
     bytecodeGenerator = &bytecode;
 
-    // allocate the js stack frame (Context & js Function)
-    bytecodeGenerator->newRegisterArray(2);
+    // allocate the js stack frame (Context & js Function & accumulator)
+    bytecodeGenerator->newRegisterArray(sizeof(EngineBase::JSStackFrame)/sizeof(Value));
 
     int returnAddress = bytecodeGenerator->newRegister();
 
diff --git a/src/qml/jsapi/qjsengine.cpp b/src/qml/jsapi/qjsengine.cpp
index 61cc0294e2..5027975d84 100644
--- a/src/qml/jsapi/qjsengine.cpp
+++ b/src/qml/jsapi/qjsengine.cpp
@@ -446,7 +446,11 @@ QJSValue QJSEngine::evaluate(const QString& program, const QString& fileName, in
     QV4::ScopedValue result(scope);
 
     QV4::Script script(ctx, program, fileName, lineNumber);
-    script.strictMode = ctx->d()->v4Function ? ctx->d()->v4Function->isStrict() : false;
+    script.strictMode = false;
+    if (v4->currentStackFrame)
+        script.strictMode = v4->currentStackFrame->v4Function->isStrict();
+    else if (v4->globalCode)
+        script.strictMode = v4->globalCode->isStrict();
     script.inheritContext = true;
     script.parse();
     if (!scope.engine->hasException)
diff --git a/src/qml/jsruntime/qv4arrayobject.cpp b/src/qml/jsruntime/qv4arrayobject.cpp
index 5201924bcc..b269b39ff3 100644
--- a/src/qml/jsruntime/qv4arrayobject.cpp
+++ b/src/qml/jsruntime/qv4arrayobject.cpp
@@ -929,12 +929,11 @@ ReturnedValue ArrayPrototype::method_filter(const BuiltinFunction *b, CallData *
     a->arrayReserve(len);
 
     ScopedValue selected(scope);
+    ScopedValue v(scope);
     ScopedCallData cData(scope, 3);
     cData->thisObject = callData->argument(1);
     cData->args[2] = instance;
 
-    ScopedValue v(scope);
-
     uint to = 0;
     for (uint k = 0; k < len; ++k) {
         bool exists;
diff --git a/src/qml/jsruntime/qv4context.cpp b/src/qml/jsruntime/qv4context.cpp
index e18d8bce83..ddb5dc4ea5 100644
--- a/src/qml/jsruntime/qv4context.cpp
+++ b/src/qml/jsruntime/qv4context.cpp
@@ -253,24 +253,24 @@ ReturnedValue QV4::ExecutionContext::simpleCall(ExecutionEngine *engine, CallDat
 {
     Q_ASSERT(function->canUseSimpleFunction());
 
-    ExecutionContextSaver ctxSaver(engine);
-
-    CallContext::Data *ctx = engine->memoryManager->allocSimpleCallContext();
-
-    ctx->callData = callData;
-    ctx->v4Function = function;
-    ctx->outer.set(engine, this->d());
+    Value *jsStackTop = engine->jsStackTop;
+    engine->jsStackTop = reinterpret_cast<QV4::Value *>(callData) + 2 + (int)function->nFormals;
     for (int i = callData->argc; i < (int)function->nFormals; ++i)
         callData->args[i] = Encode::undefined();
 
-    engine->pushContext(ctx);
-    Q_ASSERT(engine->current == ctx);
+    ExecutionContext *old = engine->currentContext;
+    engine->currentContext = this;
+    engine->current = d();
 
     ReturnedValue res = Q_V4_PROFILE(engine, function, 0);
 
     if (function->hasQmlDependencies)
         QQmlPropertyCapture::registerQmlDependencies(engine, function->compiledFunction);
-    engine->memoryManager->freeSimpleCallContext();
+
+    engine->currentContext = old;
+    engine->current = old->d();
+
+    engine->jsStackTop = jsStackTop;
 
     return res;
 }
diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index ad090682cc..08f4f29763 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -875,14 +875,13 @@ QUrl ExecutionEngine::resolvedUrl(const QString &file)
         return src;
 
     QUrl base;
-    ExecutionContext *c = currentContext;
-    while (c) {
-        CallContext *callCtx = c->asCallContext();
-        if (callCtx && callCtx->d()->v4Function) {
-            base.setUrl(callCtx->d()->v4Function->sourceFile());
+    StackFrame *f = currentStackFrame;
+    while (f) {
+        if (f->v4Function) {
+            base.setUrl(f->v4Function->sourceFile());
             break;
         }
-        c = parentContext(c);
+        f = f->parent;
     }
 
     if (base.isEmpty() && globalCode)
diff --git a/src/qml/jsruntime/qv4enginebase_p.h b/src/qml/jsruntime/qv4enginebase_p.h
index a713e8eab4..2aa6910a1c 100644
--- a/src/qml/jsruntime/qv4enginebase_p.h
+++ b/src/qml/jsruntime/qv4enginebase_p.h
@@ -65,8 +65,9 @@ namespace QV4 {
 struct EngineBase {
     struct JSStackFrame {
         // callData is directly before this
-        QV4::Value jsFunction;
-        QV4::Value context;
+        Value jsFunction;
+        Value context;
+        Value accumulator; // ###
         // registers follow
     };
 
diff --git a/src/qml/jsruntime/qv4function_p.h b/src/qml/jsruntime/qv4function_p.h
index 17311ca3c1..a6b2c0c5d0 100644
--- a/src/qml/jsruntime/qv4function_p.h
+++ b/src/qml/jsruntime/qv4function_p.h
@@ -100,7 +100,8 @@ struct Q_QML_EXPORT Function {
 
 inline unsigned int Heap::CallContext::formalParameterCount() const
 {
-    return v4Function ? v4Function->nFormals : 0;
+    Q_ASSERT(v4Function);
+    return v4Function->nFormals;
 }
 
 
diff --git a/src/qml/jsruntime/qv4functionobject.cpp b/src/qml/jsruntime/qv4functionobject.cpp
index f314d02912..f175e2cd5d 100644
--- a/src/qml/jsruntime/qv4functionobject.cpp
+++ b/src/qml/jsruntime/qv4functionobject.cpp
@@ -359,28 +359,28 @@ ReturnedValue ScriptFunction::construct(const Managed *that, CallData *callData)
         return Encode::undefined();
     CHECK_STACK_LIMITS(v4);
 
-    Scope scope(v4);
-    Scoped<ScriptFunction> f(scope, static_cast<const ScriptFunction *>(that));
+    const ScriptFunction *f = static_cast<const ScriptFunction *>(that);
 
     InternalClass *ic = f->classForConstructor();
-    ScopedObject proto(scope, ic->prototype);
-    callData->thisObject = v4->newObject(ic, proto);
+    Scope scope(v4);
+    callData->thisObject = v4->memoryManager->allocObject<Object>(ic);
 
     QV4::Function *v4Function = f->function();
     Q_ASSERT(v4Function);
 
-    ScopedContext c(scope, f->scope());
-    ScopedValue result(scope);
+    Value s = Value::fromHeapObject(f->scope());
+    ExecutionContext *outer = static_cast<ExecutionContext *>(&s);
+    ReturnedValue result;
     if (v4Function->canUseSimpleCall)
-        result = c->simpleCall(scope.engine, callData, v4Function);
+        result = outer->simpleCall(scope.engine, callData, v4Function);
     else
-        result = c->call(scope.engine, callData, v4Function, f);
+        result = outer->call(scope.engine, callData, v4Function, f);
 
     if (Q_UNLIKELY(v4->hasException))
         return Encode::undefined();
-    else if (!result->isObject())
+    else if (!Value::fromReturnedValue(result).isObject())
         return callData->thisObject.asReturnedValue();
-    return result->asReturnedValue();
+    return result;
 }
 
 ReturnedValue ScriptFunction::call(const Managed *that, CallData *callData)
diff --git a/src/qml/jsruntime/qv4lookup.cpp b/src/qml/jsruntime/qv4lookup.cpp
index 8d2d18fa2a..0fa8e1fc3d 100644
--- a/src/qml/jsruntime/qv4lookup.cpp
+++ b/src/qml/jsruntime/qv4lookup.cpp
@@ -49,7 +49,7 @@ using namespace QV4;
 ReturnedValue Lookup::lookup(const Value &thisObject, Object *o, PropertyAttributes *attrs)
 {
     ExecutionEngine *engine = o->engine();
-    Identifier *name = engine->current->v4Function->compilationUnit->runtimeStrings[nameIndex]->identifier;
+    Identifier *name = engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[nameIndex]->identifier;
     int i = 0;
     Heap::Object *obj = o->d();
     while (i < Size && obj) {
@@ -85,7 +85,7 @@ ReturnedValue Lookup::lookup(const Object *thisObject, PropertyAttributes *attrs
 {
     Heap::Object *obj = thisObject->d();
     ExecutionEngine *engine = thisObject->engine();
-    Identifier *name = engine->current->v4Function->compilationUnit->runtimeStrings[nameIndex]->identifier;
+    Identifier *name = engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[nameIndex]->identifier;
     int i = 0;
     while (i < Size && obj) {
         classList[i] = obj->internalClass;
@@ -133,7 +133,7 @@ ReturnedValue Lookup::getterGeneric(Lookup *l, ExecutionEngine *engine, const Va
         Q_ASSERT(object.isString());
         proto = engine->stringPrototype();
         Scope scope(engine);
-        ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[l->nameIndex]);
+        ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[l->nameIndex]);
         if (name->equals(engine->id_length())) {
             // special case, as the property is on the object itself
             l->getter = stringLengthGetter;
@@ -234,7 +234,7 @@ ReturnedValue Lookup::getterFallback(Lookup *l, ExecutionEngine *engine, const V
     QV4::ScopedObject o(scope, object.toObject(scope.engine));
     if (!o)
         return Encode::undefined();
-    ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[l->nameIndex]);
+    ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[l->nameIndex]);
     return o->get(name);
 }
 
@@ -580,7 +580,7 @@ ReturnedValue Lookup::globalGetterGeneric(Lookup *l, ExecutionEngine *engine)
         }
     }
     Scope scope(engine);
-    ScopedString n(scope, engine->current->v4Function->compilationUnit->runtimeStrings[l->nameIndex]);
+    ScopedString n(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[l->nameIndex]);
     return engine->throwReferenceError(n);
 }
 
@@ -697,7 +697,7 @@ bool Lookup::setterGeneric(Lookup *l, ExecutionEngine *engine, Value &object, co
         o = RuntimeHelpers::convertToObject(scope.engine, object);
         if (!o) // type error
             return false;
-        ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[l->nameIndex]);
+        ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[l->nameIndex]);
         return o->put(name, value);
     }
     return o->setLookup(l, value);
@@ -730,7 +730,7 @@ bool Lookup::setterFallback(Lookup *l, ExecutionEngine *engine, Value &object, c
     if (!o)
         return false;
 
-    ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[l->nameIndex]);
+    ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[l->nameIndex]);
     return o->put(name, value);
 }
 
diff --git a/src/qml/jsruntime/qv4object.cpp b/src/qml/jsruntime/qv4object.cpp
index 20d640bb6b..c701e981b7 100644
--- a/src/qml/jsruntime/qv4object.cpp
+++ b/src/qml/jsruntime/qv4object.cpp
@@ -508,7 +508,7 @@ bool Object::setLookup(Managed *m, Lookup *l, const Value &value)
 {
     Scope scope(static_cast<Object *>(m)->engine());
     ScopedObject o(scope, static_cast<Object *>(m));
-    ScopedString name(scope, scope.engine->current->v4Function->compilationUnit->runtimeStrings[l->nameIndex]);
+    ScopedString name(scope, scope.engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[l->nameIndex]);
 
     InternalClass *c = o->internalClass();
     uint idx = c->find(name);
@@ -1219,7 +1219,7 @@ void Heap::ArrayObject::init(const QStringList &list)
 ReturnedValue ArrayObject::getLookup(const Managed *m, Lookup *l)
 {
     Scope scope(static_cast<const Object *>(m)->engine());
-    ScopedString name(scope, scope.engine->current->v4Function->compilationUnit->runtimeStrings[l->nameIndex]);
+    ScopedString name(scope, scope.engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[l->nameIndex]);
     if (name->equals(scope.engine->id_length())) {
         // special case, as the property is on the object itself
         l->getter = Lookup::arrayLengthGetter;
diff --git a/src/qml/jsruntime/qv4runtime.cpp b/src/qml/jsruntime/qv4runtime.cpp
index e81ab783cf..81f1efbff0 100644
--- a/src/qml/jsruntime/qv4runtime.cpp
+++ b/src/qml/jsruntime/qv4runtime.cpp
@@ -308,7 +308,7 @@ void RuntimeHelpers::numberToString(QString *result, double num, int radix)
 
 ReturnedValue Runtime::method_closure(ExecutionEngine *engine, int functionId)
 {
-    QV4::Function *clos = static_cast<CompiledData::CompilationUnit*>(engine->current->v4Function->compilationUnit)->runtimeFunctions[functionId];
+    QV4::Function *clos = static_cast<CompiledData::CompilationUnit*>(engine->currentStackFrame->v4Function->compilationUnit)->runtimeFunctions[functionId];
     Q_ASSERT(clos);
     return FunctionObject::createScriptFunction(engine->currentContext, clos)->asReturnedValue();
 }
@@ -330,7 +330,7 @@ bool Runtime::method_deleteElement(ExecutionEngine *engine, const Value &base, c
 bool Runtime::method_deleteMember(ExecutionEngine *engine, const Value &base, int nameIndex)
 {
     Scope scope(engine);
-    ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[nameIndex]);
+    ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[nameIndex]);
     return method_deleteMemberString(engine, base, name);
 }
 
@@ -346,7 +346,7 @@ bool Runtime::method_deleteMemberString(ExecutionEngine *engine, const Value &ba
 bool Runtime::method_deleteName(ExecutionEngine *engine, int nameIndex)
 {
     Scope scope(engine);
-    ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[nameIndex]);
+    ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[nameIndex]);
     return engine->currentContext->deleteProperty(name);
 }
 
@@ -591,7 +591,7 @@ QV4::ReturnedValue Runtime::method_addString(ExecutionEngine *engine, const Valu
 bool Runtime::method_setProperty(ExecutionEngine *engine, const Value &object, int nameIndex, const Value &value)
 {
     Scope scope(engine);
-    ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[nameIndex]);
+    ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[nameIndex]);
     ScopedObject o(scope, object.toObject(engine));
     if (!o)
         return false;
@@ -741,14 +741,14 @@ ReturnedValue Runtime::method_foreachNextPropertyName(const Value &foreach_itera
 bool Runtime::method_setActivationProperty(ExecutionEngine *engine, int nameIndex, const Value &value)
 {
     Scope scope(engine);
-    ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[nameIndex]);
+    ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[nameIndex]);
     return engine->currentContext->setProperty(name, value);
 }
 
 ReturnedValue Runtime::method_getProperty(ExecutionEngine *engine, const Value &object, int nameIndex)
 {
     Scope scope(engine);
-    ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[nameIndex]);
+    ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[nameIndex]);
 
     ScopedObject o(scope, object);
     if (o)
@@ -768,7 +768,7 @@ ReturnedValue Runtime::method_getProperty(ExecutionEngine *engine, const Value &
 ReturnedValue Runtime::method_getActivationProperty(ExecutionEngine *engine, int nameIndex)
 {
     Scope scope(engine);
-    ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[nameIndex]);
+    ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[nameIndex]);
     return engine->currentContext->getProperty(name);
 }
 
@@ -1003,12 +1003,12 @@ ReturnedValue Runtime::method_callGlobalLookup(ExecutionEngine *engine, uint ind
     Scope scope(engine);
     Q_ASSERT(callData->thisObject.isUndefined());
 
-    Lookup *l = engine->current->v4Function->compilationUnit->runtimeLookups + index;
+    Lookup *l = engine->currentStackFrame->v4Function->compilationUnit->runtimeLookups + index;
     ScopedFunctionObject o(scope, l->globalGetter(l, engine));
     if (!o)
         return engine->throwTypeError();
 
-    ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[l->nameIndex]);
+    ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[l->nameIndex]);
     if (o->d() == scope.engine->evalFunction()->d() && name->equals(scope.engine->id_eval()))
         return static_cast<EvalFunction *>(o.getPointer())->evalCall(callData, true);
 
@@ -1020,7 +1020,7 @@ ReturnedValue Runtime::method_callActivationProperty(ExecutionEngine *engine, in
 {
     Q_ASSERT(callData->thisObject.isUndefined());
     Scope scope(engine);
-    ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[nameIndex]);
+    ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[nameIndex]);
 
     ScopedObject base(scope);
     ScopedValue func(scope, engine->currentContext->getPropertyAndBase(name, base.getRef()));
@@ -1048,7 +1048,7 @@ ReturnedValue Runtime::method_callActivationProperty(ExecutionEngine *engine, in
 ReturnedValue Runtime::method_callProperty(ExecutionEngine *engine, int nameIndex, CallData *callData)
 {
     Scope scope(engine);
-    ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[nameIndex]);
+    ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[nameIndex]);
     ScopedObject baseObject(scope, callData->thisObject);
     if (!baseObject) {
         Q_ASSERT(!callData->thisObject.isEmpty());
@@ -1075,7 +1075,7 @@ ReturnedValue Runtime::method_callProperty(ExecutionEngine *engine, int nameInde
 
 ReturnedValue Runtime::method_callPropertyLookup(ExecutionEngine *engine, uint index, CallData *callData)
 {
-    Lookup *l = engine->current->v4Function->compilationUnit->runtimeLookups + index;
+    Lookup *l = engine->currentStackFrame->v4Function->compilationUnit->runtimeLookups + index;
     Value v;
     v = l->getter(l, engine, callData->thisObject);
     Object *o = v.objectValue();
@@ -1116,7 +1116,7 @@ ReturnedValue Runtime::method_constructGlobalLookup(ExecutionEngine *engine, uin
     Scope scope(engine);
     Q_ASSERT(callData->thisObject.isUndefined());
 
-    Lookup *l = engine->current->v4Function->compilationUnit->runtimeLookups + index;
+    Lookup *l = engine->currentStackFrame->v4Function->compilationUnit->runtimeLookups + index;
     ScopedObject f(scope, l->globalGetter(l, engine));
     if (f)
         return f->construct(callData);
@@ -1128,7 +1128,7 @@ ReturnedValue Runtime::method_constructGlobalLookup(ExecutionEngine *engine, uin
 ReturnedValue Runtime::method_constructActivationProperty(ExecutionEngine *engine, int nameIndex, CallData *callData)
 {
     Scope scope(engine);
-    ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[nameIndex]);
+    ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[nameIndex]);
     ScopedValue func(scope, engine->currentContext->getProperty(name));
     if (scope.engine->hasException)
         return Encode::undefined();
@@ -1153,7 +1153,7 @@ ReturnedValue Runtime::method_constructProperty(ExecutionEngine *engine, int nam
 {
     Scope scope(engine);
     ScopedObject thisObject(scope, callData->thisObject.toObject(engine));
-    ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[nameIndex]);
+    ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[nameIndex]);
     if (scope.engine->hasException)
         return Encode::undefined();
 
@@ -1166,7 +1166,7 @@ ReturnedValue Runtime::method_constructProperty(ExecutionEngine *engine, int nam
 
 ReturnedValue Runtime::method_constructPropertyLookup(ExecutionEngine *engine, uint index, CallData *callData)
 {
-    Lookup *l = engine->current->v4Function->compilationUnit->runtimeLookups + index;
+    Lookup *l = engine->currentStackFrame->v4Function->compilationUnit->runtimeLookups + index;
     Value v;
     v = l->getter(l, engine, callData->thisObject);
     Object *o = v.objectValue();
@@ -1215,7 +1215,7 @@ ReturnedValue Runtime::method_typeofValue(ExecutionEngine *engine, const Value &
 QV4::ReturnedValue Runtime::method_typeofName(ExecutionEngine *engine, int nameIndex)
 {
     Scope scope(engine);
-    ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[nameIndex]);
+    ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[nameIndex]);
     ScopedValue prop(scope, engine->currentContext->getProperty(name));
     // typeof doesn't throw. clear any possible exception
     scope.engine->hasException = false;
@@ -1247,7 +1247,7 @@ void Runtime::method_pushCatchScope(NoThrowEngine *engine, int exceptionVarNameI
 {
     engine->jsAlloca(1); // keep this symmetric with pushWithScope
     ExecutionContext *c = engine->currentContext;
-    engine->pushContext(c->newCatchContext(engine->current->v4Function->compilationUnit->runtimeStrings[exceptionVarNameIndex], engine->catchException(0)));
+    engine->pushContext(c->newCatchContext(engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[exceptionVarNameIndex], engine->catchException(0)));
     Q_ASSERT(engine->jsStackTop == engine->currentContext + 2);
 }
 
@@ -1261,7 +1261,7 @@ void Runtime::method_popScope(NoThrowEngine *engine)
 void Runtime::method_declareVar(ExecutionEngine *engine, bool deletable, int nameIndex)
 {
     Scope scope(engine);
-    ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[nameIndex]);
+    ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[nameIndex]);
     engine->currentContext->createMutableBinding(name, deletable);
 }
 
@@ -1273,7 +1273,7 @@ ReturnedValue Runtime::method_arrayLiteral(ExecutionEngine *engine, Value *value
 ReturnedValue Runtime::method_objectLiteral(ExecutionEngine *engine, const QV4::Value *args, int classId, int arrayValueCount, int arrayGetterSetterCountAndFlags)
 {
     Scope scope(engine);
-    QV4::InternalClass *klass = static_cast<CompiledData::CompilationUnit*>(engine->current->v4Function->compilationUnit)->runtimeClasses[classId];
+    QV4::InternalClass *klass = static_cast<CompiledData::CompilationUnit*>(engine->currentStackFrame->v4Function->compilationUnit)->runtimeClasses[classId];
     ScopedObject o(scope, engine->newObject(klass, engine->objectPrototype()));
 
     {
@@ -1369,7 +1369,7 @@ ReturnedValue Runtime::method_getQmlContext(NoThrowEngine *engine)
 
 ReturnedValue Runtime::method_regexpLiteral(ExecutionEngine *engine, int id)
 {
-    return static_cast<CompiledData::CompilationUnit*>(engine->current->v4Function->compilationUnit)->runtimeRegularExpressions[id].asReturnedValue();
+    return static_cast<CompiledData::CompilationUnit*>(engine->currentStackFrame->v4Function->compilationUnit)->runtimeRegularExpressions[id].asReturnedValue();
 }
 
 ReturnedValue Runtime::method_getQmlScopeObjectProperty(ExecutionEngine *engine, const Value &context, int propertyIndex, bool captureRequired)
@@ -1421,7 +1421,7 @@ ReturnedValue Runtime::method_getQmlImportedScripts(NoThrowEngine *engine)
 QV4::ReturnedValue Runtime::method_getQmlSingleton(QV4::NoThrowEngine *engine, int nameIndex)
 {
     Scope scope(engine);
-    ScopedString name(scope, engine->current->v4Function->compilationUnit->runtimeStrings[nameIndex]);
+    ScopedString name(scope, engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[nameIndex]);
     return engine->qmlSingletonWrapper(name);
 }
 
diff --git a/src/qml/jsruntime/qv4scopedvalue_p.h b/src/qml/jsruntime/qv4scopedvalue_p.h
index f6cb6fda5d..5e3e71a30f 100644
--- a/src/qml/jsruntime/qv4scopedvalue_p.h
+++ b/src/qml/jsruntime/qv4scopedvalue_p.h
@@ -109,7 +109,7 @@ struct Scope {
     ~Scope() {
 #ifndef QT_NO_DEBUG
         Q_ASSERT(engine->jsStackTop >= mark);
-        Q_ASSERT(engine->currentContext < mark);
+//        Q_ASSERT(engine->currentContext < mark);
         memset(mark, 0, (engine->jsStackTop - mark)*sizeof(Value));
 #endif
 #ifdef V4_USE_VALGRIND
diff --git a/src/qml/jsruntime/qv4vme_moth.cpp b/src/qml/jsruntime/qv4vme_moth.cpp
index 6297f42c81..97e9a90b5a 100644
--- a/src/qml/jsruntime/qv4vme_moth.cpp
+++ b/src/qml/jsruntime/qv4vme_moth.cpp
@@ -455,17 +455,21 @@ QV4::ReturnedValue VME::exec(Function *function, const FunctionObject *jsFunctio
     const uchar *exceptionHandler = 0;
 
     QV4::Scope scope(engine);
-    int nFormals = function->nFormals;
-    stack = scope.alloc(function->compiledFunction->nRegisters + nFormals + 2 + sizeof(EngineBase::JSStackFrame)/sizeof(QV4::Value));
-    QV4::Value &accumulator = *stack;
-    ++stack;
-    memcpy(stack, &engine->current->callData->thisObject, (nFormals + 1)*sizeof(Value));
-    stack += nFormals + 1;
+    if (!function->canUseSimpleFunction()) {
+        int nFormals = function->nFormals;
+        stack = scope.alloc(nFormals + 1 + function->compiledFunction->nRegisters + sizeof(EngineBase::JSStackFrame)/sizeof(QV4::Value));
+        memcpy(stack, &engine->current->callData->thisObject, (nFormals + 1)*sizeof(Value));
+        stack += nFormals + 1;
+    } else {
+        stack = scope.alloc(function->compiledFunction->nRegisters + sizeof(EngineBase::JSStackFrame)/sizeof(QV4::Value));
+    }
     frame.jsFrame = reinterpret_cast<EngineBase::JSStackFrame *>(stack);
     frame.jsFrame->context = engine->current;
     if (jsFunction)
         frame.jsFrame->jsFunction = *jsFunction;
 
+    QV4::Value &accumulator = frame.jsFrame->accumulator;
+
     if (QV4::Debugging::Debugger *debugger = engine->debugger())
         debugger->enteringFunction();
 
diff --git a/src/qml/qml/qqmljavascriptexpression.cpp b/src/qml/qml/qqmljavascriptexpression.cpp
index e00c8d30be..231708da70 100644
--- a/src/qml/qml/qqmljavascriptexpression.cpp
+++ b/src/qml/qml/qqmljavascriptexpression.cpp
@@ -217,10 +217,11 @@ QV4::ReturnedValue QQmlJavaScriptExpression::evaluate(QV4::CallData *callData, b
 
     QV4::ExecutionEngine *v4 = QV8Engine::getV4(ep->v8engine());
     QV4::Scope scope(v4);
+    QV4::ScopedValue value(scope);
     QV4::ScopedValue result(scope, QV4::Primitive::undefinedValue());
     callData->thisObject = v4->globalObject;
     if (scopeObject()) {
-        QV4::ScopedValue value(scope, QV4::QObjectWrapper::wrap(v4, scopeObject()));
+         value = QV4::QObjectWrapper::wrap(v4, scopeObject());
         if (value->isObject())
             callData->thisObject = value;
     }
diff --git a/src/qml/qml/v8/qqmlbuiltinfunctions.cpp b/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
index ebf8918d31..a3874e4e65 100644
--- a/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
+++ b/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
@@ -1908,10 +1908,10 @@ ReturnedValue GlobalExtensions::method_qsTr(const BuiltinFunction *b, CallData *
         int length = lastDot - (lastSlash + 1);
         context = (lastSlash > -1) ? path.mid(lastSlash + 1, (length > -1) ? length : -1) : QString();
     } else {
-        ExecutionContext *parentCtx = scope.engine->currentContext;
+        ExecutionEngine::StackFrame *frame = scope.engine->currentStackFrame;
         // The first non-empty source URL in the call stack determines the translation context.
-        while (!!parentCtx && context.isEmpty()) {
-            if (CompiledData::CompilationUnit *unit = parentCtx->d()->v4Function->compilationUnit) {
+        while (frame && context.isEmpty()) {
+            if (CompiledData::CompilationUnit *unit = frame->v4Function->compilationUnit) {
                 QString fileName = unit->fileName();
                 QUrl url(unit->fileName());
                 if (url.isValid() && url.isRelative()) {
@@ -1923,7 +1923,7 @@ ReturnedValue GlobalExtensions::method_qsTr(const BuiltinFunction *b, CallData *
                 }
                 context = QFileInfo(context).baseName();
             }
-            parentCtx = scope.engine->parentContext(parentCtx);
+            frame = frame->parent;
         }
     }