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Bug 1422726 - Optimize addEnumerableDataProperty by adding a fast path for the most common case. r=bhackett

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--HG--
extra : rebase_source : 4f12ef98636ea4523c01ff75f3be79ee905d160a
This commit is contained in:
Jan de Mooij 2017-12-04 14:56:06 +01:00
parent 5e3043911a
commit fdcdfff048
1 changed files with 66 additions and 24 deletions
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90
js/src/vm/Shape.cpp
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@ -618,15 +618,78 @@ NativeObject::addDataPropertyInternal(JSContext* cx,
return shape;
}
static MOZ_ALWAYS_INLINE Shape*
PropertyTreeReadBarrier(Shape* parent, Shape* shape)
{
JS::Zone* zone = shape->zone();
if (zone->needsIncrementalBarrier()) {
// We need a read barrier for the shape tree, since these are weak
// pointers.
Shape* tmp = shape;
TraceManuallyBarrieredEdge(zone->barrierTracer(), &tmp, "read barrier");
MOZ_ASSERT(tmp == shape);
return shape;
}
if (MOZ_LIKELY(!zone->isGCSweepingOrCompacting() ||
!IsAboutToBeFinalizedUnbarriered(&shape)))
{
if (shape->isMarkedGray())
UnmarkGrayShapeRecursively(shape);
return shape;
}
// The shape we've found is unreachable and due to be finalized, so
// remove our weak reference to it and don't use it.
MOZ_ASSERT(parent->isMarkedAny());
parent->removeChild(shape);
return nullptr;
}
/* static */ Shape*
NativeObject::addEnumerableDataProperty(JSContext* cx, HandleNativeObject obj, HandleId id)
{
// Like addProperty(Internal), but optimized for the common case of adding a
// new enumerable data property.
AutoKeepShapeTables keep(cx);
AutoCheckShapeConsistency check(obj);
// Fast path for non-dictionary shapes with a single kid.
do {
AutoCheckCannotGC nogc;
Shape* lastProperty = obj->lastProperty();
if (lastProperty->inDictionary())
break;
KidsPointer* kidp = &lastProperty->kids;
if (!kidp->isShape())
break;
Shape* kid = kidp->toShape();
MOZ_ASSERT(!kid->inDictionary());
if (kid->propidRaw() != id ||
kid->isAccessorShape() ||
kid->attributes() != JSPROP_ENUMERATE ||
kid->base()->unowned() != lastProperty->base()->unowned())
{
break;
}
MOZ_ASSERT(kid->isDataProperty());
kid = PropertyTreeReadBarrier(lastProperty, kid);
if (!kid)
break;
if (!obj->setLastProperty(cx, kid))
return nullptr;
return kid;
} while (0);
AutoKeepShapeTables keep(cx);
ShapeTable* table = nullptr;
ShapeTable::Entry* entry = nullptr;
@ -1676,30 +1739,9 @@ PropertyTree::inlinedGetChild(JSContext* cx, Shape* parent, Handle<StackShape> c
}
if (existingShape) {
JS::Zone* zone = existingShape->zone();
if (zone->needsIncrementalBarrier()) {
/*
* We need a read barrier for the shape tree, since these are weak
* pointers.
*/
Shape* tmp = existingShape;
TraceManuallyBarrieredEdge(zone->barrierTracer(), &tmp, "read barrier");
MOZ_ASSERT(tmp == existingShape);
existingShape = PropertyTreeReadBarrier(parent, existingShape);
if (existingShape)
return existingShape;
}
if (!zone->isGCSweepingOrCompacting() ||
!IsAboutToBeFinalizedUnbarriered(&existingShape))
{
if (existingShape->isMarkedGray())
UnmarkGrayShapeRecursively(existingShape);
return existingShape;
}
/*
* The shape we've found is unreachable and due to be finalized, so
* remove our weak reference to it and don't use it.
*/
MOZ_ASSERT(parent->isMarkedAny());
parent->removeChild(existingShape);
}
RootedShape parentRoot(cx, parent);