QML: Make Heap::Object and all subclasses trivial

GCC6 might dead-store-eliminate out our secret write to Base::mmdata,
because it expects all memory content to be "undefined" before
constructor calls. Clang might take the same approach if the constructor
of Heap::Object is removed.

By making these structs trivial, it also makes them memcpy-able.

Change-Id: I055b2ad28311b997fbe059849ebda4d5894eaa9b
Reviewed-by: Simon Hausmann <[email protected]>

1 files changed, 4 insertions, 3 deletions

diff --git a/src/qml/jsruntime/qv4script.cpp b/src/qml/jsruntime/qv4script.cpp
index e3475e5cd6..787047806a 100644
--- a/src/qml/jsruntime/qv4script.cpp
+++ b/src/qml/jsruntime/qv4script.cpp
@@ -65,7 +65,7 @@ namespace QV4 {
 namespace Heap {
 
 struct QmlBindingWrapper : FunctionObject {
-    QmlBindingWrapper(QV4::QmlContext *scope, Function *f);
+    void init(QV4::QmlContext *scope, Function *f);
 };
 
 }
@@ -84,9 +84,10 @@ using namespace QV4;
 
 DEFINE_OBJECT_VTABLE(QmlBindingWrapper);
 
-Heap::QmlBindingWrapper::QmlBindingWrapper(QV4::QmlContext *scope, Function *f)
-    : Heap::FunctionObject(scope, scope->d()->engine->id_eval(), /*createProto = */ false)
+void Heap::QmlBindingWrapper::init(QV4::QmlContext *scope, Function *f)
 {
+    Heap::FunctionObject::init(scope, scope->d()->engine->id_eval(), /*createProto = */ false);
+
     Q_ASSERT(scope->inUse());
 
     function = f;