Refactor our NaN boxing to be more efficient

* Use a unified way to store all Managed objects inside
a Value, instead of distinguishing between strings
and other objects.

* On 64 bit we store pointers as pointers, so accessing them
through Scoped<> objects is cheap. This implies that doubles
are now stored in a mangled form (xor'ed with a mask).

Change-Id: I582e0fb167a62c0c527c6bfa3452550e37944069
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

1 files changed, 14 insertions, 4 deletions

diff --git a/src/qml/jsruntime/qv4managed_p.h b/src/qml/jsruntime/qv4managed_p.h
index 42b6841959..f13f699748 100644
--- a/src/qml/jsruntime/qv4managed_p.h
+++ b/src/qml/jsruntime/qv4managed_p.h
@@ -226,6 +226,9 @@ public:
 
     template <typename T>
     T *as() {
+        // ### FIXME:
+        if (!this)
+            return 0;
 #if !defined(QT_NO_QOBJECT_CHECK)
         reinterpret_cast<T *>(this)->qt_check_for_QMANAGED_macro(*reinterpret_cast<T *>(this));
 #endif
@@ -233,6 +236,9 @@ public:
     }
     template <typename T>
     const T *as() const {
+        // ### FIXME:
+        if (!this)
+            return 0;
 #if !defined(QT_NO_QOBJECT_CHECK)
         reinterpret_cast<T *>(this)->qt_check_for_QMANAGED_macro(*reinterpret_cast<T *>(const_cast<Managed *>(this)));
 #endif
@@ -315,6 +321,8 @@ public:
         return type;
     }
 
+    ReturnedValue asReturnedValue() { return Value::fromManaged(this).asReturnedValue(); }
+
     union {
         uint _data;
         struct {
@@ -345,10 +353,12 @@ private:
     friend struct ObjectIterator;
 };
 
-// ### Not a good placement
-template<typename T>
-inline T *Value::as() const { Managed *m = isObject() ? managed() : 0; return m ? m->as<T>() : 0; }
-
+inline ReturnedValue Managed::construct(CallData *d) {
+    return vtbl->construct(this, d);
+}
+inline ReturnedValue Managed::call(CallData *d) {
+    return vtbl->call(this, d);
+}
 
 }