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 <simon.hausmann@qt.io>

1 files changed, 4 insertions, 4 deletions

diff --git a/tools/qmljs/qmljs.cpp b/tools/qmljs/qmljs.cpp
index 964afc265b..e9454c0f8d 100644
--- a/tools/qmljs/qmljs.cpp
+++ b/tools/qmljs/qmljs.cpp
@@ -61,9 +61,9 @@ using namespace QV4;
 struct Print: FunctionObject
 {
     struct Data : Heap::FunctionObject {
-        Data(ExecutionContext *scope)
-            : Heap::FunctionObject(scope, QStringLiteral("print"))
+        void init(ExecutionContext *scope)
         {
+            Heap::FunctionObject::init(scope, QStringLiteral("print"));
         }
     };
     V4_OBJECT(FunctionObject)
@@ -86,9 +86,9 @@ DEFINE_OBJECT_VTABLE(Print);
 struct GC: public FunctionObject
 {
     struct Data : Heap::FunctionObject {
-        Data(ExecutionContext *scope)
-            : Heap::FunctionObject(scope, QStringLiteral("gc"))
+        void init(ExecutionContext *scope)
         {
+            Heap::FunctionObject::init(scope, QStringLiteral("gc"));
         }
 
     };