Avoid some unnecessary fast-properties map creations.

(1) When we have just normalized and re-fastified a map, we don't need to copy it again to set the is_prototype bit.
(2) When defining accessors causes a non-prototype object to go slow, don't force re-fastification.

BUG=v8:3267
LOG=n
R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/706243002

Cr-Commit-Position: refs/heads/master@{#25221}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25221 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
parent 1a64b02d
......@@ -9505,13 +9505,17 @@ void JSObject::OptimizeAsPrototype(Handle<JSObject> object,
JSObject::NormalizeProperties(object, KEEP_INOBJECT_PROPERTIES, 0,
"NormalizeAsPrototype");
}
bool has_just_copied_map = false;
if (!object->HasFastProperties()) {
JSObject::MigrateSlowToFast(object, 0, "OptimizeAsPrototype");
has_just_copied_map = true;
}
if (mode == FAST_PROTOTYPE && object->HasFastProperties() &&
!object->map()->is_prototype_map()) {
Handle<Map> new_map = Map::Copy(handle(object->map()), "CopyAsPrototype");
JSObject::MigrateToMap(object, new_map);
if (!has_just_copied_map) {
Handle<Map> new_map = Map::Copy(handle(object->map()), "CopyAsPrototype");
JSObject::MigrateToMap(object, new_map);
}
object->map()->set_is_prototype_map(true);
}
}
......
......@@ -1455,10 +1455,8 @@ RUNTIME_FUNCTION(Runtime_DefineAccessorPropertyUnchecked) {
RUNTIME_ASSERT((unchecked & ~(READ_ONLY | DONT_ENUM | DONT_DELETE)) == 0);
PropertyAttributes attr = static_cast<PropertyAttributes>(unchecked);
bool fast = obj->HasFastProperties();
RETURN_FAILURE_ON_EXCEPTION(
isolate, JSObject::DefineAccessor(obj, name, getter, setter, attr));
if (fast) JSObject::MigrateSlowToFast(obj, 0, "RuntimeDefineAccessor");
return isolate->heap()->undefined_value();
}
......
......@@ -303,7 +303,7 @@ assertTrue(Object.isFrozen(Object.freeze(function(){"use strict";})));
// Also test a simpler case
obj = {};
Object.defineProperty(obj, 'accessor', {
Object.defineProperty(obj, 'accessor2', {
get: function() { return 42 },
set: function() { accessorDidRun = true },
configurable: true,
......
......@@ -44,5 +44,4 @@ assertTrue(%HaveSameMap(o, o2));
Object.defineProperty(o, "foo", { set: setter, configurable: true });
Object.defineProperty(o2, "foo", { set: setter, configurable: true });
// TODO(ishell): this should eventually become assertTrue().
assertFalse(%HaveSameMap(o, o2));
assertTrue(%HaveSameMap(o, o2));
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