Streamline code allocating MemberData

Saves around 1% in the Splay benchmark.

Change-Id: I32c8807d6688351beea2a34d945e8ef87b31355f
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

4 files changed, 12 insertions, 34 deletions

diff --git a/src/qml/jsruntime/qv4memberdata.cpp b/src/qml/jsruntime/qv4memberdata.cpp
index 5646a44891..d5f75415cc 100644
--- a/src/qml/jsruntime/qv4memberdata.cpp
+++ b/src/qml/jsruntime/qv4memberdata.cpp
@@ -52,30 +52,16 @@ void MemberData::markObjects(Heap::Base *that, ExecutionEngine *e)
         m->data[i].mark(e);
 }
 
-static Heap::MemberData *reallocateHelper(ExecutionEngine *e, Heap::MemberData *old, uint n)
+Heap::MemberData *MemberData::allocate(ExecutionEngine *e, uint n, Heap::MemberData *old)
 {
+    Q_ASSERT(!old || old->size < n);
+
     uint alloc = sizeof(Heap::MemberData) + (n)*sizeof(Value);
-    Scope scope(e);
-    Scoped<MemberData> newMemberData(scope, e->memoryManager->allocManaged<MemberData>(alloc));
+    Heap::MemberData *m = e->memoryManager->allocManaged<MemberData>(alloc);
     if (old)
-        memcpy(newMemberData->d_unchecked(), old, sizeof(Heap::MemberData) + old->size * sizeof(Value));
+        memcpy(m, old, sizeof(Heap::MemberData) + old->size * sizeof(Value));
     else
-        newMemberData->d_unchecked()->init();
-    newMemberData->d()->size = n;
-    return newMemberData->d();
-}
-
-Heap::MemberData *MemberData::allocate(ExecutionEngine *e, uint n)
-{
-    return reallocateHelper(e, 0, n);
-}
-
-Heap::MemberData *MemberData::reallocate(ExecutionEngine *e, Heap::MemberData *old, uint n)
-{
-    uint s = old ? old->size : 0;
-    if (n < s)
-        return old;
-
-    // n is multiplied by two to leave room for growth
-    return reallocateHelper(e, old, qMax((uint)4, 2*n));
+        m->init();
+    m->size = n;
+    return m;
 }
diff --git a/src/qml/jsruntime/qv4memberdata_p.h b/src/qml/jsruntime/qv4memberdata_p.h
index 969eee3619..5c89dfe8ec 100644
--- a/src/qml/jsruntime/qv4memberdata_p.h
+++ b/src/qml/jsruntime/qv4memberdata_p.h
@@ -79,8 +79,7 @@ struct MemberData : Managed
     Value *data() { return d()->data; }
     inline uint size() const { return d()->size; }
 
-    static Heap::MemberData *allocate(QV4::ExecutionEngine *e, uint n);
-    static Heap::MemberData *reallocate(QV4::ExecutionEngine *e, Heap::MemberData *old, uint n);
+    static Heap::MemberData *allocate(QV4::ExecutionEngine *e, uint n, Heap::MemberData *old = 0);
 
     static void markObjects(Heap::Base *that, ExecutionEngine *e);
 };
diff --git a/src/qml/jsruntime/qv4object.cpp b/src/qml/jsruntime/qv4object.cpp
index 00e6d230da..8acca16dd0 100644
--- a/src/qml/jsruntime/qv4object.cpp
+++ b/src/qml/jsruntime/qv4object.cpp
@@ -61,7 +61,9 @@ DEFINE_OBJECT_VTABLE(Object);
 void Object::setInternalClass(InternalClass *ic)
 {
     d()->internalClass = ic;
-    ensureMemberData();
+    if ((ic->size > d()->inlineMemberSize && !d()->memberData) ||
+        (d()->memberData && d()->memberData->size < ic->size - d()->inlineMemberSize))
+        d()->memberData = MemberData::allocate(ic->engine, ic->size - d()->inlineMemberSize, d()->memberData);
 }
 
 void Object::getProperty(uint index, Property *p, PropertyAttributes *attrs) const
@@ -225,13 +227,6 @@ void Object::markObjects(Heap::Base *that, ExecutionEngine *e)
         o->prototype->mark(e);
 }
 
-void Object::ensureMemberData()
-{
-    QV4::InternalClass *ic = internalClass();
-    if (ic->size > d()->inlineMemberSize)
-        d()->memberData = MemberData::reallocate(ic->engine, d()->memberData, ic->size - d()->inlineMemberSize);
-}
-
 void Object::insertMember(String *s, const Property *p, PropertyAttributes attributes)
 {
     uint idx;
diff --git a/src/qml/jsruntime/qv4object_p.h b/src/qml/jsruntime/qv4object_p.h
index 91d9f03ad1..6c679deb10 100644
--- a/src/qml/jsruntime/qv4object_p.h
+++ b/src/qml/jsruntime/qv4object_p.h
@@ -367,8 +367,6 @@ protected:
     static void advanceIterator(Managed *m, ObjectIterator *it, Value *name, uint *index, Property *p, PropertyAttributes *attributes);
     static uint getLength(const Managed *m);
 
-    void ensureMemberData();
-
 private:
     ReturnedValue internalGet(String *name, bool *hasProperty) const;
     ReturnedValue internalGetIndexed(uint index, bool *hasProperty) const;