Revision: 10659
Author: [email protected]
Date: Thu Feb 9 05:07:46 2012
Log: Revert 9111036: Promote double arrays to FAST_ELEMENT that use
generic KeyedLoadIC
It tanked Kraken.
[email protected]
Review URL: https://chromiumcodereview.appspot.com/9368024
http://code.google.com/p/v8/source/detail?r=10659
Modified:
/branches/bleeding_edge/src/ic.cc
/branches/bleeding_edge/src/runtime.cc
=======================================
--- /branches/bleeding_edge/src/ic.cc Thu Feb 9 02:19:46 2012
+++ /branches/bleeding_edge/src/ic.cc Thu Feb 9 05:07:46 2012
@@ -1145,17 +1145,6 @@
} else if (key->IsSmi() && (target() !=
*non_strict_arguments_stub())) {
stub = ComputeStub(receiver, LOAD, kNonStrictMode, stub);
}
- // If the IC is being replaced by the generic stub, loads from
- // FAST_DOUBLE_ELEMENTS arrays will cause unboxing in Crankshafted
- // code. To prevent these expensive allocations, proactively
promote
- // arrays to FAST_ELEMENTS ElementKinds.
- if (*stub == *generic_stub()) {
- if (receiver->HasFastDoubleElements()) {
- MaybeObject* maybe_object =
- receiver->TransitionElementsKind(FAST_ELEMENTS);
- if (maybe_object->IsFailure()) return maybe_object;
- }
- }
}
} else {
TRACE_GENERIC_IC("KeyedLoadIC", "force generic");
=======================================
--- /branches/bleeding_edge/src/runtime.cc Thu Feb 9 02:46:50 2012
+++ /branches/bleeding_edge/src/runtime.cc Thu Feb 9 05:07:46 2012
@@ -4271,24 +4271,14 @@
// If value is the hole do the general lookup.
}
}
- } else if (args.at<Object>(1)->IsSmi()) {
- // Getting properties from FAST_DOUBLE_ELEMENTS arrays causes
boxing. To
- // proactively avoid excessive boxing, transition
FAST_DOUBLE_ELEMENTS
- // arrays to FAST_ELEMENTS if they are accessed via this function,
which
- // is called by the KeyedLoadIC::GenericStub.
- Handle<JSObject> js_object(args.at<JSObject>(0));
- if (js_object->HasFastDoubleElements()) {
- MaybeObject* maybe_object =
- js_object->TransitionElementsKind(FAST_ELEMENTS);
- if (maybe_object->IsFailure()) return maybe_object;
- }
-
+ } else if (FLAG_smi_only_arrays && args.at<Object>(1)->IsSmi()) {
// JSObject without a string key. If the key is a Smi, check for a
// definite out-of-bounds access to elements, which is a strong
indicator
// that subsequent accesses will also call the runtime. Proactively
// transition elements to FAST_ELEMENTS to avoid excessive boxing of
// doubles for those future calls in the case that the elements would
// become FAST_DOUBLE_ELEMENTS.
+ Handle<JSObject> js_object(args.at<JSObject>(0));
ElementsKind elements_kind = js_object->GetElementsKind();
if (elements_kind == FAST_SMI_ONLY_ELEMENTS ||
elements_kind == FAST_DOUBLE_ELEMENTS) {
--
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