Cleanup the ExecutionContextSaver

Always operate on the current context (as that's what we do
in practice anyway).

Change-Id: I4171207a7a86e69aa685754956c0764ac6e152a7
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

src/qml/jsruntime/qv4debugging.cpp

@@ -66,7 +66,7 @@ void Debugger::JavaScriptJob::run()
 {
     Scope scope(engine);
 
-    ExecutionContextSaver saver(scope, engine->currentContext());
+    ExecutionContextSaver saver(scope);
 
     if (frameNr > 0) {
         Value *savedContexts = scope.alloc(frameNr);

src/qml/jsruntime/qv4engine_p.h

@@ -348,6 +348,7 @@ public:
     void enableProfiler();
 
     Heap::ExecutionContext *pushGlobalContext();
+    void pushContext(Heap::ExecutionContext *context);
     void pushContext(CallContext *context);
     Heap::ExecutionContext *popContext();
 
@@ -441,13 +442,19 @@ public:
     void assertObjectBelongsToEngine(const Heap::Base &baseObject);
 };
 
+inline void ExecutionEngine::pushContext(Heap::ExecutionContext *context)
+{
+    Q_ASSERT(current && context);
+    context->parent = current;
+    current = context;
+}
+
 inline void ExecutionEngine::pushContext(CallContext *context)
 {
-    Q_ASSERT(current && context && context->d());
-    context->d()->parent = current;
-    current = context->d();
+    pushContext(context->d());
 }
 
+
 inline Heap::ExecutionContext *ExecutionEngine::popContext()
 {
     Q_ASSERT(current->parent);
@@ -467,7 +474,7 @@ Heap::ExecutionContext::ExecutionContext(ExecutionEngine *engine, ContextType t)
     , strictMode(false)
     , lineNumber(-1)
 {
-    engine->current = this;
+    engine->pushContext(this);
 }
 
 

src/qml/jsruntime/qv4functionobject.cpp

@@ -434,17 +434,19 @@ ReturnedValue ScriptFunction::construct(const Managed *that, CallData *callData)
     CHECK_STACK_LIMITS(v4);
 
     Scope scope(v4);
+    ExecutionContextSaver ctxSaver(scope);
+
     Scoped<ScriptFunction> f(scope, static_cast<const ScriptFunction *>(that));
 
     InternalClass *ic = scope.engine->emptyClass;
     ScopedObject proto(scope, f->protoForConstructor());
     ScopedObject obj(scope, v4->newObject(ic, proto));
 
+
     ScopedContext context(scope, v4->currentContext());
     callData->thisObject = obj.asReturnedValue();
     Scoped<CallContext> ctx(scope, context->newCallContext(f, callData));
 
-    ExecutionContextSaver ctxSaver(scope, context);
     ScopedValue result(scope, Q_V4_PROFILE(v4, f->function()));
 
     if (f->function()->compiledFunction->hasQmlDependencies())
@@ -466,12 +468,12 @@ ReturnedValue ScriptFunction::call(const Managed *that, CallData *callData)
     CHECK_STACK_LIMITS(v4);
 
     Scope scope(v4);
+    ExecutionContextSaver ctxSaver(scope);
+
     Scoped<ScriptFunction> f(scope, static_cast<const ScriptFunction *>(that));
     ScopedContext context(scope, v4->currentContext());
-
     Scoped<CallContext> ctx(scope, context->newCallContext(f, callData));
 
-    ExecutionContextSaver ctxSaver(scope, context);
     ScopedValue result(scope, Q_V4_PROFILE(v4, f->function()));
 
     if (f->function()->compiledFunction->hasQmlDependencies())
@@ -522,14 +524,14 @@ ReturnedValue SimpleScriptFunction::construct(const Managed *that, CallData *cal
     CHECK_STACK_LIMITS(v4);
 
     Scope scope(v4);
+    ExecutionContextSaver ctxSaver(scope);
+
     Scoped<SimpleScriptFunction> f(scope, static_cast<const SimpleScriptFunction *>(that));
 
     InternalClass *ic = scope.engine->emptyClass;
     ScopedObject proto(scope, f->protoForConstructor());
     callData->thisObject = v4->newObject(ic, proto);
 
-    ExecutionContextSaver ctxSaver(scope, v4->currentContext());
-
     CallContext::Data ctx(v4);
 #ifndef QT_NO_DEBUG
     ctx.mm_data = 0; // make sure we don't run into the assertion in setVTable when allocating a context on the stack
@@ -564,9 +566,9 @@ ReturnedValue SimpleScriptFunction::call(const Managed *that, CallData *callData
     CHECK_STACK_LIMITS(v4);
 
     Scope scope(v4);
-    Scoped<SimpleScriptFunction> f(scope, static_cast<const SimpleScriptFunction *>(that));
+    ExecutionContextSaver ctxSaver(scope);
 
-    ExecutionContextSaver ctxSaver(scope, v4->currentContext());
+    Scoped<SimpleScriptFunction> f(scope, static_cast<const SimpleScriptFunction *>(that));
 
     CallContext::Data ctx(v4);
 #ifndef QT_NO_DEBUG
@@ -625,7 +627,7 @@ ReturnedValue BuiltinFunction::call(const Managed *that, CallData *callData)
     CHECK_STACK_LIMITS(v4);
 
     Scope scope(v4);
-    ExecutionContextSaver ctxSaver(scope, v4->currentContext());
+    ExecutionContextSaver ctxSaver(scope);
 
     CallContext::Data ctx(v4);
 #ifndef QT_NO_DEBUG
@@ -649,7 +651,7 @@ ReturnedValue IndexedBuiltinFunction::call(const Managed *that, CallData *callDa
     CHECK_STACK_LIMITS(v4);
 
     Scope scope(v4);
-    ExecutionContextSaver ctxSaver(scope, v4->currentContext());
+    ExecutionContextSaver ctxSaver(scope);
 
     CallContext::Data ctx(v4);
 #ifndef QT_NO_DEBUG

src/qml/jsruntime/qv4globalobject.cpp

@@ -339,10 +339,9 @@ ReturnedValue EvalFunction::evalCall(CallData *callData, bool directCall) const
 
     ExecutionEngine *v4 = engine();
     Scope scope(v4);
+    ExecutionContextSaver ctxSaver(scope);
 
     ScopedContext parentContext(scope, v4->currentContext());
-    ExecutionContextSaver ctxSaver(scope, parentContext);
-
     ScopedContext ctx(scope, parentContext.getPointer());
 
     if (!directCall) {

src/qml/jsruntime/qv4scopedvalue_p.h

@@ -416,20 +416,11 @@ struct ExecutionContextSaver
     ExecutionEngine *engine;
     Value *savedContext;
 
-    ExecutionContextSaver(Scope &scope, ExecutionContext *context)
-        : engine(context->d()->engine)
+    ExecutionContextSaver(Scope &scope)
+        : engine(scope.engine)
         , savedContext(scope.alloc(1))
     {
-        savedContext->setM(context->d());
-#if QT_POINTER_SIZE == 4
-        savedContext->setTag(QV4::Value::Managed_Type);
-#endif
-    }
-    ExecutionContextSaver(Scope &scope, Heap::ExecutionContext *context)
-        : engine(context->engine)
-        , savedContext(scope.alloc(1))
-    {
-        savedContext->setM(context);
+        savedContext->setM(scope.engine->currentContext());
 #if QT_POINTER_SIZE == 4
         savedContext->setTag(QV4::Value::Managed_Type);
 #endif

src/qml/jsruntime/qv4script.cpp

@@ -117,6 +117,8 @@ ReturnedValue QmlBindingWrapper::call(const Managed *that, CallData *callData)
     CHECK_STACK_LIMITS(v4);
 
     Scope scope(v4);
+    ExecutionContextSaver ctxSaver(scope);
+
     QV4::Function *f = This->function();
     if (!f)
         return QV4::Encode::undefined();
@@ -124,7 +126,6 @@ ReturnedValue QmlBindingWrapper::call(const Managed *that, CallData *callData)
     ScopedContext context(scope, v4->currentContext());
     Scoped<CallContext> ctx(scope, context->newCallContext(This, callData));
 
-    ExecutionContextSaver ctxSaver(scope, context);
     ScopedValue result(scope, Q_V4_PROFILE(v4, f));
 
     return result->asReturnedValue();
@@ -237,7 +238,7 @@ ReturnedValue Script::run()
     if (qmlContext.isUndefined()) {
         TemporaryAssignment<Function*> savedGlobalCode(engine->globalCode, vmFunction);
 
-        ExecutionContextSaver ctxSaver(valueScope, scope);
+        ExecutionContextSaver ctxSaver(valueScope);
         ContextStateSaver stateSaver(valueScope, scope);
         scope->d()->strictMode = vmFunction->isStrict();
         scope->d()->lookups = vmFunction->compilationUnit->runtimeLookups;

src/qml/memory/qv4mm.cpp

@@ -483,7 +483,7 @@ void MemoryManager::sweep(bool lastSweep)
 
     // some execution contexts are allocated on the stack, make sure we clear their markBit as well
     if (!lastSweep) {
-        Heap::ExecutionContext *ctx = engine()->current;
+        Heap::ExecutionContext *ctx = engine()->currentContext();
         while (ctx) {
             ctx->clearMarkBit();
             ctx = ctx->parent;