AllocationSites: when updating allocation site transition information,

AllocationSites: when updating allocation site transition information,
be careful to merge feedback appropriately. For example, one array may
have gone holey, and then another allocated at the same place instead
went DOUBLE but remained packed. In this case the ElementsKind
ultimately stored in the AllocationSite should be HOLEY_DOUBLE.

BUG=
R=verwaest@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=15629

[mvstanton, 2013-07-11 11:28:41]

Hi Toon, here is the "generalizing feedback" code we discussed. Have a look when
possible, thanks!
--Michael

[Toon Verwaest, 2013-07-11 13:04:40]

lgtm with comment

https://codereview.chromium.org/18531007/diff/1/src/objects.cc
File src/objects.cc (right):

https://codereview.chromium.org/18531007/diff/1/src/objects.cc#newcode12321
src/objects.cc:12321: if (IsHoleyElementsKind(kind) &&
IsFastPackedElementsKind(to_kind)) {
You don't need to check whether the to_kind is packed. GetHoley on Holey will
return to_kind (I believe).

https://codereview.chromium.org/18531007/diff/1/src/objects.cc#newcode12343
src/objects.cc:12343: if (IsHoleyElementsKind(kind) &&
IsFastPackedElementsKind(to_kind)) {
Same as above.

[mvstanton, 2013-07-11 13:08:26]

right on, thanks!
--Michael

https://codereview.chromium.org/18531007/diff/1/src/objects.cc
File src/objects.cc (right):

https://codereview.chromium.org/18531007/diff/1/src/objects.cc#newcode12321
src/objects.cc:12321: if (IsHoleyElementsKind(kind) &&
IsFastPackedElementsKind(to_kind)) {
On 2013/07/11 13:04:40, Toon Verwaest wrote:
> You don't need to check whether the to_kind is packed. GetHoley on Holey will
> return to_kind (I believe).

Done.

https://codereview.chromium.org/18531007/diff/1/src/objects.cc#newcode12343
src/objects.cc:12343: if (IsHoleyElementsKind(kind) &&
IsFastPackedElementsKind(to_kind)) {
On 2013/07/11 13:04:40, Toon Verwaest wrote:
> Same as above.

Done.

[mvstanton, 2013-07-11 13:08:44]

Committed patchset #2 manually as r15629 (presubmit successful).