Optimize setting new properties on objects

When a property on an object is set for the first time,
this triggers a change in internal class for the object.
Record that change in the lookup, and do the same transition
in the future.

Change-Id: Ib0e8ac61ce3aaecb736532600740cec51996e3d6
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

4 files changed, 94 insertions, 9 deletions

diff --git a/src/qml/jsruntime/qv4lookup.cpp b/src/qml/jsruntime/qv4lookup.cpp
index b5ea877bd4..345611d46c 100644
--- a/src/qml/jsruntime/qv4lookup.cpp
+++ b/src/qml/jsruntime/qv4lookup.cpp
@@ -362,4 +362,55 @@ void Lookup::setter0(Lookup *l, const Value &object, const Value &value)
     setterGeneric(l, object, value);
 }
 
+void Lookup::setterInsert0(Lookup *l, const Value &object, const Value &value)
+{
+    Object *o = object.asObject();
+    if (o && o->internalClass == l->classList[0]) {
+        if (!o->prototype) {
+            o->memberData[l->index].value = value;
+            o->internalClass = l->classList[3];
+            return;
+        }
+    }
+
+    l->setter = setterGeneric;
+    setterGeneric(l, object, value);
+}
+
+void Lookup::setterInsert1(Lookup *l, const Value &object, const Value &value)
+{
+    Object *o = object.asObject();
+    if (o && o->internalClass == l->classList[0]) {
+        Object *p = o->prototype;
+        if (p && p->internalClass == l->classList[1]) {
+            o->memberData[l->index].value = value;
+            o->internalClass = l->classList[3];
+            return;
+        }
+    }
+
+    l->setter = setterGeneric;
+    setterGeneric(l, object, value);
+}
+
+void Lookup::setterInsert2(Lookup *l, const Value &object, const Value &value)
+{
+    Object *o = object.asObject();
+    if (o && o->internalClass == l->classList[0]) {
+        Object *p = o->prototype;
+        if (p && p->internalClass == l->classList[1]) {
+            p = p->prototype;
+            if (p && p->internalClass == l->classList[2]) {
+                o->ensureMemberIndex(l->index);
+                o->memberData[l->index].value = value;
+                o->internalClass = l->classList[3];
+                return;
+            }
+        }
+    }
+
+    l->setter = setterGeneric;
+    setterGeneric(l, object, value);
+}
+
 QT_END_NAMESPACE
diff --git a/src/qml/jsruntime/qv4lookup_p.h b/src/qml/jsruntime/qv4lookup_p.h
index e77552826a..3763182e84 100644
--- a/src/qml/jsruntime/qv4lookup_p.h
+++ b/src/qml/jsruntime/qv4lookup_p.h
@@ -53,7 +53,7 @@ QT_BEGIN_NAMESPACE
 namespace QV4 {
 
 struct Lookup {
-    enum { Size = 3 };
+    enum { Size = 4 };
     union {
         void (*getter)(Lookup *l, Value *result, const Value &object);
         void (*globalGetter)(Lookup *l, ExecutionContext *ctx, Value *result);
@@ -82,6 +82,9 @@ struct Lookup {
 
     static void setterGeneric(Lookup *l, const Value &object, const Value &value);
     static void setter0(Lookup *l, const Value &object, const Value &value);
+    static void setterInsert0(Lookup *l, const Value &object, const Value &value);
+    static void setterInsert1(Lookup *l, const Value &object, const Value &value);
+    static void setterInsert2(Lookup *l, const Value &object, const Value &value);
 
     Property *lookup(Object *obj, PropertyAttributes *attrs);
 
diff --git a/src/qml/jsruntime/qv4object.cpp b/src/qml/jsruntime/qv4object.cpp
index 45a0a19e2f..01be2d7091 100644
--- a/src/qml/jsruntime/qv4object.cpp
+++ b/src/qml/jsruntime/qv4object.cpp
@@ -293,14 +293,8 @@ void Object::markObjects(Managed *that)
     o->markArrayObjects();
 }
 
-Property *Object::insertMember(String *s, PropertyAttributes attributes)
+void Object::ensureMemberIndex(uint idx)
 {
-    uint idx;
-    internalClass = internalClass->addMember(s, attributes, &idx);
-
-    if (attributes.isAccessor())
-        hasAccessorProperty = 1;
-
     if (idx >= memberDataAlloc) {
         memberDataAlloc = qMax((uint)8, 2*memberDataAlloc);
         Property *newMemberData = new Property[memberDataAlloc];
@@ -310,6 +304,18 @@ Property *Object::insertMember(String *s, PropertyAttributes attributes)
             delete [] memberData;
         memberData = newMemberData;
     }
+}
+
+Property *Object::insertMember(String *s, PropertyAttributes attributes)
+{
+    uint idx;
+    internalClass = internalClass->addMember(s, attributes, &idx);
+
+    if (attributes.isAccessor())
+        hasAccessorProperty = 1;
+
+    ensureMemberIndex(idx);
+
     return memberData + idx;
 }
 
@@ -540,7 +546,8 @@ void Object::setLookup(Managed *m, Lookup *l, const Value &value)
 {
     Object *o = static_cast<Object *>(m);
 
-    uint idx = o->internalClass->find(l->name);
+    InternalClass *c = o->internalClass;
+    uint idx = c->find(l->name);
     if (!o->isArrayObject() || idx != ArrayObject::LengthPropertyIndex) {
         if (idx != UINT_MAX && o->internalClass->propertyData[idx].isData() && o->internalClass->propertyData[idx].isWritable()) {
             l->classList[0] = o->internalClass;
@@ -557,6 +564,29 @@ void Object::setLookup(Managed *m, Lookup *l, const Value &value)
     }
 
     o->put(l->name, value);
+
+    if (o->internalClass == c)
+        return;
+    idx = o->internalClass->find(l->name);
+    if (idx == UINT_MAX)
+        return;
+    l->classList[0] = c;
+    l->classList[3] = o->internalClass;
+    l->index = idx;
+    if (!o->prototype) {
+        l->setter = Lookup::setterInsert0;
+        return;
+    }
+    o = o->prototype;
+    l->classList[1] = o->internalClass;
+    if (!o->prototype) {
+        l->setter = Lookup::setterInsert1;
+        return;
+    }
+    o = o->prototype;
+    l->classList[2] = o->internalClass;
+    if (!o->prototype)
+        l->setter = Lookup::setterInsert2;
 }
 
 Property *Object::advanceIterator(Managed *m, ObjectIterator *it, String **name, uint *index, PropertyAttributes *attrs)
diff --git a/src/qml/jsruntime/qv4object_p.h b/src/qml/jsruntime/qv4object_p.h
index e6b1e04286..ea8911124d 100644
--- a/src/qml/jsruntime/qv4object_p.h
+++ b/src/qml/jsruntime/qv4object_p.h
@@ -328,6 +328,7 @@ public:
 
         return false;
     }
+    void ensureMemberIndex(uint idx);
 
     inline Value get(String *name, bool *hasProperty = 0)
     { return vtbl->get(this, name, hasProperty); }