Cleanup element normalization logic

Cleanup element normalization logic

BUG=

Committed: https://crrev.com/99b59d16bf8620e06e7f09f40d6a26f340feb247
Cr-Commit-Position: refs/heads/master@{#29686}

[Toon Verwaest, 2015-07-15 13:15:56]

verwaest@chromium.org changed reviewers:
+ ishell@chromium.org

[Toon Verwaest, 2015-07-15 13:15:57]

ptal

[Igor Sheludko, 2015-07-15 14:58:06]

lgtm with suggestion:

https://codereview.chromium.org/1241883002/diff/1/src/objects.cc
File src/objects.cc (right):

https://codereview.chromium.org/1241883002/diff/1/src/objects.cc#newcode5536
src/objects.cc:5536: length == 0 ?
isolate->factory()->empty_slow_element_dictionary()
Probably it would be better if GetNormalizedElementDictionary() could return a
proper empty dictionary when length is zero.

[Toon Verwaest, 2015-07-15 15:07:58]

https://codereview.chromium.org/1241883002/diff/1/src/objects.cc
File src/objects.cc (right):

https://codereview.chromium.org/1241883002/diff/1/src/objects.cc#newcode5536
src/objects.cc:5536: length == 0 ?
isolate->factory()->empty_slow_element_dictionary()
On 2015/07/15 14:58:06, Igor Sheludko wrote:
> Probably it would be better if GetNormalizedElementDictionary() could return a
> proper empty dictionary when length is zero.

It, unfortunately, cannot. The empty dictionary isn't exactly empty, and we're
only guaranteed that nobody will add elements to it if the receiver holding it
is prevented from being extended. Otherwise we'll end up with shared elements
between objects that reuse this "empty" dictionary. We've had that before ...

[Toon Verwaest, 2015-07-15 15:08:03]

The CQ bit was checked by verwaest@chromium.org

[commit-bot: I haz the power, 2015-07-15 15:08:09]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1241883002/1

[commit-bot: I haz the power, 2015-07-15 15:12:49]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-07-15 15:12:51]

Try jobs failed on following builders:
  v8_linux_gcc_compile_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_gcc_compile_rel/bu...)

(exceeded global retry quota)

[Toon Verwaest, 2015-07-15 15:25:36]

The CQ bit was checked by verwaest@chromium.org

[Toon Verwaest, 2015-07-15 15:25:36]

The patchset sent to the CQ was uploaded after l-g-t-m from ishell@chromium.org
Link to the patchset: https://codereview.chromium.org/1241883002/#ps20001
(title: " ")

[commit-bot: I haz the power, 2015-07-15 15:25:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1241883002/20001

[commit-bot: I haz the power, 2015-07-15 15:57:31]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-07-15 15:57:57]

Patchset 2 (id:??) landed as
https://crrev.com/99b59d16bf8620e06e7f09f40d6a26f340feb247
Cr-Commit-Position: refs/heads/master@{#29686}