Reviewers: Vyacheslav Egorov,
Description:
Speed up cloning objects by avoiding a write barrier check.
Please review this at http://codereview.chromium.org/8274032/
SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge/
Affected files:
M src/heap.cc
Index: src/heap.cc
===================================================================
--- src/heap.cc (revision 9609)
+++ src/heap.cc (working copy)
@@ -3695,6 +3695,8 @@
int object_size = map->instance_size();
Object* clone;
+ WriteBarrierMode wb_mode = UPDATE_WRITE_BARRIER;
+
// If we're forced to always allocate, we use the general allocation
// functions which may leave us with an object in old space.
if (always_allocate()) {
@@ -3711,6 +3713,7 @@
JSObject::kHeaderSize,
(object_size - JSObject::kHeaderSize) / kPointerSize);
} else {
+ wb_mode = SKIP_WRITE_BARRIER;
{ MaybeObject* maybe_clone = new_space_.AllocateRaw(object_size);
if (!maybe_clone->ToObject(&clone)) return maybe_clone;
}
@@ -3739,7 +3742,7 @@
}
if (!maybe_elem->ToObject(&elem)) return maybe_elem;
}
- JSObject::cast(clone)->set_elements(FixedArrayBase::cast(elem));
+ JSObject::cast(clone)->set_elements(FixedArrayBase::cast(elem),
wb_mode);
}
// Update properties if necessary.
if (properties->length() > 0) {
@@ -3747,7 +3750,7 @@
{ MaybeObject* maybe_prop = CopyFixedArray(properties);
if (!maybe_prop->ToObject(&prop)) return maybe_prop;
}
- JSObject::cast(clone)->set_properties(FixedArray::cast(prop));
+ JSObject::cast(clone)->set_properties(FixedArray::cast(prop), wb_mode);
}
// Return the new clone.
return clone;
--
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