Refactor Maps' code_cache

Refactor Maps' code_cache

Most maps have a small code cache (often only one entry), so this patch
optimizes memory consumption of such cases by using plain FixedArrays,
only switching to CodeCacheHashTables when the number of cached entries
gets so large that linear-scan lookups get too slow.

On loading inbox.google.com, this gets the aggregate size of all maps'
code caches (there are about 13,600 of them) from 4300 KB to 970 KB.

Committed: https://crrev.com/31882103773436538fa929b1b867a6cb42fe72bf
Cr-Commit-Position: refs/heads/master@{#36681}

[Jakob Kummerow, 2016-06-02 11:37:28]

Description was changed from

==========
Refactor Maps' code_cache

Most maps have a small code cache (often only one entry), so this patch
optimizes memory consumption of such cases by using plain FixedArrays,
only switching to CodeCacheHashTables when the number of cached entries
gets so large that linear-scan lookups get too slow.
==========

to

==========
Refactor Maps' code_cache

Most maps have a small code cache (often only one entry), so this patch
optimizes memory consumption of such cases by using plain FixedArrays,
only switching to CodeCacheHashTables when the number of cached entries
gets so large that linear-scan lookups get too slow.

On loading inbox.google.com, this gets the aggregate size of all maps'
code caches (there are about 13,600 of them) from 4300 KB to 970 KB.
==========

[Jakob Kummerow, 2016-06-02 11:39:08]

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

[Jakob Kummerow, 2016-06-02 11:39:09]

Toon: as discussed, PTAL.

Ulan/Hannes: I can haz heap rubberstamp plz?

[Toon Verwaest, 2016-06-02 12:01:19]

Very nice, LGTM.

[ulan, 2016-06-02 12:28:55]

ulan@chromium.org changed reviewers:
+ ulan@chromium.org

[ulan, 2016-06-02 12:28:55]

heap lgtm

[Jakob Kummerow, 2016-06-02 12:33:09]

The CQ bit was checked by jkummerow@chromium.org

[commit-bot: I haz the power, 2016-06-02 12:33:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2021373002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2021373002/20001

[commit-bot: I haz the power, 2016-06-02 12:38:08]

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

[commit-bot: I haz the power, 2016-06-02 12:38:10]

Try jobs failed on following builders:
  v8_win_rel_ng on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_win_rel_ng/builds/8070)

[Jakob Kummerow, 2016-06-02 12:46:11]

The CQ bit was checked by jkummerow@chromium.org

[Jakob Kummerow, 2016-06-02 12:46:11]

The patchset sent to the CQ was uploaded after l-g-t-m from ulan@chromium.org,
verwaest@chromium.org
Link to the patchset: https://codereview.chromium.org/2021373002/#ps40001
(title: "windows don't want no constexpr")

[commit-bot: I haz the power, 2016-06-02 12:46:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2021373002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2021373002/40001

[commit-bot: I haz the power, 2016-06-02 13:16:49]

Description was changed from

==========
Refactor Maps' code_cache

Most maps have a small code cache (often only one entry), so this patch
optimizes memory consumption of such cases by using plain FixedArrays,
only switching to CodeCacheHashTables when the number of cached entries
gets so large that linear-scan lookups get too slow.

On loading inbox.google.com, this gets the aggregate size of all maps'
code caches (there are about 13,600 of them) from 4300 KB to 970 KB.
==========

to

==========
Refactor Maps' code_cache

Most maps have a small code cache (often only one entry), so this patch
optimizes memory consumption of such cases by using plain FixedArrays,
only switching to CodeCacheHashTables when the number of cached entries
gets so large that linear-scan lookups get too slow.

On loading inbox.google.com, this gets the aggregate size of all maps'
code caches (there are about 13,600 of them) from 4300 KB to 970 KB.
==========

[commit-bot: I haz the power, 2016-06-02 13:16:50]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-06-02 13:19:32]

Description was changed from

==========
Refactor Maps' code_cache

Most maps have a small code cache (often only one entry), so this patch
optimizes memory consumption of such cases by using plain FixedArrays,
only switching to CodeCacheHashTables when the number of cached entries
gets so large that linear-scan lookups get too slow.

On loading inbox.google.com, this gets the aggregate size of all maps'
code caches (there are about 13,600 of them) from 4300 KB to 970 KB.
==========

to

==========
Refactor Maps' code_cache

Most maps have a small code cache (often only one entry), so this patch
optimizes memory consumption of such cases by using plain FixedArrays,
only switching to CodeCacheHashTables when the number of cached entries
gets so large that linear-scan lookups get too slow.

On loading inbox.google.com, this gets the aggregate size of all maps'
code caches (there are about 13,600 of them) from 4300 KB to 970 KB.

Committed: https://crrev.com/31882103773436538fa929b1b867a6cb42fe72bf
Cr-Commit-Position: refs/heads/master@{#36681}
==========

[commit-bot: I haz the power, 2016-06-02 13:19:33]

Patchset 3 (id:??) landed as
https://crrev.com/31882103773436538fa929b1b867a6cb42fe72bf
Cr-Commit-Position: refs/heads/master@{#36681}