Move conversion of this object into generated code

When a non strict mode function uses the this object, we
need to make sure it's being correctly converted into a
object before being accessed. So far this was being done
by ScriptFunction::call. Move this into the generated code to
avoid overhead for methods not using 'this', and simplify our
ScriptFunction::call() implementation.

Change-Id: I739f4a89d29ed8082ce59e48d1523776224fc29d
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

5 files changed, 19 insertions, 18 deletions

diff --git a/src/qml/jsruntime/qv4engine_p.h b/src/qml/jsruntime/qv4engine_p.h
index c585714dd0..3413238f3d 100644
--- a/src/qml/jsruntime/qv4engine_p.h
+++ b/src/qml/jsruntime/qv4engine_p.h
@@ -369,8 +369,7 @@ struct ExecutionContextSaver
     }
     ~ExecutionContextSaver()
     {
-        while (engine->current != savedContext)
-            engine->popContext();
+        engine->current = savedContext;
     }
 };
 
diff --git a/src/qml/jsruntime/qv4functionobject.cpp b/src/qml/jsruntime/qv4functionobject.cpp
index a270689b43..35e4202790 100644
--- a/src/qml/jsruntime/qv4functionobject.cpp
+++ b/src/qml/jsruntime/qv4functionobject.cpp
@@ -471,14 +471,6 @@ ReturnedValue ScriptFunction::call(Managed *that, CallData *callData)
 
     CallContext *ctx = context->newCallContext(f, callData);
 
-    if (!f->strictMode && !callData->thisObject.isObject()) {
-        if (callData->thisObject.isNullOrUndefined()) {
-            ctx->callData->thisObject = v4->globalObject->asReturnedValue();
-        } else {
-            ctx->callData->thisObject = callData->thisObject.toObject(context)->asReturnedValue();
-        }
-    }
-
     if (f->function->compiledFunction->hasQmlDependencies())
         QmlContextWrapper::registerQmlDependencies(ctx->engine, f->function->compiledFunction);
 
@@ -568,14 +560,6 @@ ReturnedValue SimpleScriptFunction::call(Managed *that, CallData *callData)
     ExecutionContext *context = v4->current;
     ExecutionContext *ctx = context->newCallContext(stackSpace, scope.alloc(f->varCount), f.getPointer(), callData);
 
-    if (!f->strictMode && !callData->thisObject.isObject()) {
-        if (callData->thisObject.isNullOrUndefined()) {
-            ctx->callData->thisObject = v4->globalObject->asReturnedValue();
-        } else {
-            ctx->callData->thisObject = callData->thisObject.toObject(context)->asReturnedValue();
-        }
-    }
-
     if (f->function->compiledFunction->hasQmlDependencies())
         QmlContextWrapper::registerQmlDependencies(v4, f->function->compiledFunction);
 
diff --git a/src/qml/jsruntime/qv4runtime.cpp b/src/qml/jsruntime/qv4runtime.cpp
index d8ebe635bd..22af24e527 100644
--- a/src/qml/jsruntime/qv4runtime.cpp
+++ b/src/qml/jsruntime/qv4runtime.cpp
@@ -1277,6 +1277,18 @@ ReturnedValue __qmljs_get_imported_scripts(NoThrowContext *ctx)
     return context->importedScripts.value();
 }
 
+void __qmljs_builtin_convert_this_to_object(ExecutionContext *ctx)
+{
+    SafeValue *t = &ctx->callData->thisObject;
+    if (t->isObject())
+        return;
+    if (t->isNullOrUndefined()) {
+        *t = ctx->engine->globalObject->asReturnedValue();
+    } else {
+        *t = t->toObject(ctx)->asReturnedValue();
+    }
+}
+
 } // namespace QV4
 
 QT_END_NAMESPACE
diff --git a/src/qml/jsruntime/qv4runtime_p.h b/src/qml/jsruntime/qv4runtime_p.h
index 4f6f3a33d4..b2d2d211eb 100644
--- a/src/qml/jsruntime/qv4runtime_p.h
+++ b/src/qml/jsruntime/qv4runtime_p.h
@@ -144,6 +144,7 @@ QV4::ReturnedValue __qmljs_builtin_define_array(QV4::ExecutionContext *ctx, QV4:
 void __qmljs_builtin_define_getter_setter(QV4::ExecutionContext *ctx, const QV4::ValueRef object, const QV4::StringRef name, const QV4::ValueRef getter, const QV4::ValueRef setter);
 QV4::ReturnedValue __qmljs_builtin_define_object_literal(QV4::ExecutionContext *ctx, const QV4::Value *args, int classId);
 QV4::ReturnedValue __qmljs_builtin_setup_arguments_object(ExecutionContext *ctx);
+void __qmljs_builtin_convert_this_to_object(ExecutionContext *ctx);
 
 QV4::ReturnedValue __qmljs_value_from_string(QV4::String *string);
 QV4::ReturnedValue __qmljs_lookup_runtime_regexp(QV4::ExecutionContext *ctx, int id);
diff --git a/src/qml/jsruntime/qv4vme_moth.cpp b/src/qml/jsruntime/qv4vme_moth.cpp
index 82d9599582..74a42b6f2f 100644
--- a/src/qml/jsruntime/qv4vme_moth.cpp
+++ b/src/qml/jsruntime/qv4vme_moth.cpp
@@ -478,6 +478,11 @@ QV4::ReturnedValue VME::run(QV4::ExecutionContext *context, const uchar *code,
         STOREVALUE(instr.result, __qmljs_builtin_setup_arguments_object(context));
     MOTH_END_INSTR(CallBuiltinSetupArgumentsObject)
 
+    MOTH_BEGIN_INSTR(CallBuiltinConvertThisToObject)
+        __qmljs_builtin_convert_this_to_object(context);
+        CHECK_EXCEPTION;
+    MOTH_END_INSTR(CallBuiltinConvertThisToObject)
+
     MOTH_BEGIN_INSTR(CreateValue)
         Q_ASSERT(instr.callData + instr.argc + qOffsetOf(QV4::CallData, args)/sizeof(QV4::SafeValue) <= stackSize);
         QV4::CallData *callData = reinterpret_cast<QV4::CallData *>(stack + instr.callData);