Move the prototype into the internal class

This saves another pointer on all Objects.

Currently introduces a slight performance regression
on some of the v8 benchmarks, that needs addressing.

Change-Id: I87de8e1d198d2683f4e903c467ce2a60ba542243
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 18 insertions, 8 deletions

diff --git a/src/qml/jsruntime/qv4internalclass_p.h b/src/qml/jsruntime/qv4internalclass_p.h
index 3c4e0838d9..031f66793b 100644
--- a/src/qml/jsruntime/qv4internalclass_p.h
+++ b/src/qml/jsruntime/qv4internalclass_p.h
@@ -223,6 +223,7 @@ struct InternalClassTransition
     union {
         Identifier *id;
         const VTable *vtable;
+        Heap::Object *prototype;
     };
     InternalClass *lookup;
     int flags;
@@ -230,6 +231,7 @@ struct InternalClassTransition
         // range 0-0xff is reserved for attribute changes
         NotExtensible = 0x100,
         VTableChange = 0x200,
+        PrototypeChange = 0x201
     };
 
     bool operator==(const InternalClassTransition &other) const
@@ -242,6 +244,7 @@ struct InternalClassTransition
 struct InternalClass : public QQmlJS::Managed {
     ExecutionEngine *engine;
     const VTable *vtable;
+    Heap::Object *prototype;
 
     PropertyHash propertyTable; // id to valueIndex
     SharedInternalClassData<Identifier *> nameMap;
@@ -257,30 +260,37 @@ struct InternalClass : public QQmlJS::Managed {
     uint size;
     bool extensible;
 
-    InternalClass *nonExtensible();
-    InternalClass *changeVTable(const VTable *vt) {
+    Q_REQUIRED_RESULT InternalClass *nonExtensible();
+    Q_REQUIRED_RESULT InternalClass *changeVTable(const VTable *vt) {
         if (vtable == vt)
             return this;
         return changeVTableImpl(vt);
     }
+    Q_REQUIRED_RESULT InternalClass *changePrototype(Heap::Object *proto) {
+        if (prototype == proto)
+            return this;
+        return changePrototypeImpl(proto);
+    }
 
     static void addMember(Object *object, String *string, PropertyAttributes data, uint *index);
-    InternalClass *addMember(String *string, PropertyAttributes data, uint *index = 0);
-    InternalClass *addMember(Identifier *identifier, PropertyAttributes data, uint *index = 0);
-    InternalClass *changeMember(Identifier *identifier, PropertyAttributes data, uint *index = 0);
+    Q_REQUIRED_RESULT InternalClass *addMember(String *string, PropertyAttributes data, uint *index = 0);
+    Q_REQUIRED_RESULT InternalClass *addMember(Identifier *identifier, PropertyAttributes data, uint *index = 0);
+    Q_REQUIRED_RESULT InternalClass *changeMember(Identifier *identifier, PropertyAttributes data, uint *index = 0);
     static void changeMember(Object *object, String *string, PropertyAttributes data, uint *index = 0);
     static void removeMember(Object *object, Identifier *id);
     uint find(const String *string);
     uint find(const Identifier *id);
 
-    InternalClass *sealed();
-    InternalClass *frozen();
-    InternalClass *propertiesFrozen() const;
+    Q_REQUIRED_RESULT InternalClass *sealed();
+    Q_REQUIRED_RESULT InternalClass *frozen();
+    Q_REQUIRED_RESULT InternalClass *propertiesFrozen() const;
 
     void destroy();
+    void mark(ExecutionEngine *e);
 
 private:
     Q_QML_EXPORT InternalClass *changeVTableImpl(const VTable *vt);
+    Q_QML_EXPORT InternalClass *changePrototypeImpl(Heap::Object *proto);
     InternalClass *addMemberImpl(Identifier *identifier, PropertyAttributes data, uint *index);
     friend struct ExecutionEngine;
     InternalClass(ExecutionEngine *engine);