Use proper write barriers instead of RecordWrites when copying object elements.

Use proper write barriers instead of RecordWrites when copying object elements.

This CL brings us one step closer to untangle the runtime-gc dependency, i.e. RecordWrites should not be called from the runtime.

BUG=

Committed: https://crrev.com/23bf71d706c4cb6e34c3501b8023e6b6c438d83d
Cr-Commit-Position: refs/heads/master@{#32074}

[Hannes Payer (out of office), 2015-11-17 13:37:04]

Description was changed from

==========
Use proper write barriers instead of RecordWrites when copying object elements.

BUG=
==========

to

==========
Use proper write barriers instead of RecordWrites when copying object elements.

This CL brings us one step closer to untangle the runtime-gc dependency, i.e.
RecordWrites should not be called from the runtime.

BUG=
==========

[Hannes Payer (out of office), 2015-11-17 13:37:04]

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

[ulan, 2015-11-17 13:51:48]

lgtm

https://codereview.chromium.org/1456533002/diff/40001/src/elements.cc
File src/elements.cc (right):

https://codereview.chromium.org/1456533002/diff/40001/src/elements.cc#newcode141
src/elements.cc:141: IsFastObjectElementsKind(from_kind) &&
IsFastObjectElementsKind(to_kind);
We can precompute the mode here:
WriteBarrierMode write_barrier_mode = 
   IsFastObjectElementsKind(from_kind) && IsFastObjectElementsKind(to_kind) ?
UPDATE_WRITE_BARRIER : SKIP_WRITE_BARRIER.

[Hannes Payer (out of office), 2015-11-18 09:02:17]

https://codereview.chromium.org/1456533002/diff/40001/src/elements.cc
File src/elements.cc (right):

https://codereview.chromium.org/1456533002/diff/40001/src/elements.cc#newcode141
src/elements.cc:141: IsFastObjectElementsKind(from_kind) &&
IsFastObjectElementsKind(to_kind);
On 2015/11/17 13:51:48, ulan wrote:
> We can precompute the mode here:
> WriteBarrierMode write_barrier_mode = 
>    IsFastObjectElementsKind(from_kind) && IsFastObjectElementsKind(to_kind) ?
> UPDATE_WRITE_BARRIER : SKIP_WRITE_BARRIER.

Done.

[Hannes Payer (out of office), 2015-11-18 09:02:25]

The CQ bit was checked by hpayer@chromium.org

[Hannes Payer (out of office), 2015-11-18 09:02:26]

The patchset sent to the CQ was uploaded after l-g-t-m from ulan@chromium.org
Link to the patchset: https://codereview.chromium.org/1456533002/#ps60001
(title: " ")

[commit-bot: I haz the power, 2015-11-18 09:02:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1456533002/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1456533002/60001

[commit-bot: I haz the power, 2015-11-18 09:46:27]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-11-18 09:46:55]

Patchset 4 (id:??) landed as
https://crrev.com/23bf71d706c4cb6e34c3501b8023e6b6c438d83d
Cr-Commit-Position: refs/heads/master@{#32074}