Reland of [builtins] DeleteProperty: Handle last-added fast properties

Reland of [builtins] DeleteProperty: Handle last-added fast properties

In general, deleting a property from a fast-properties object
requires transitioning the object to dictionary mode. However,
when the most-recently-added property is deleted, we can simply
roll back the last map transition that the object went through.

This is a performance experiment: it should make things faster,
but if it turns out to have more negative than positive impact,
we will have to revert it.

TBR=bmeurer@chromium.org (just adding a comment)

Previously reviewed at https://codereview.chromium.org/2830093002
Previously landed as 98acfb36e1a / r44799

Review-Url: https://codereview.chromium.org/2840583002
Cr-Commit-Position: refs/heads/master@{#44808}
Committed: https://chromium.googlesource.com/v8/v8/+/0f88153075bbc97d4701533454cf11a690ad7210

[Jakob Kummerow, 2017-04-24 15:05:23]

Created Reland of [builtins] DeleteProperty: Handle last-added fast properties

[Jakob Kummerow, 2017-04-24 15:06:53]

Description was changed from

==========
Reland of [builtins] DeleteProperty: Handle last-added fast properties (patchset
#1 id:1 of https://codereview.chromium.org/2843473002/ )

Reason for revert:
relanding with fix

Original issue's description:
> Revert of [builtins] DeleteProperty: Handle last-added fast properties
(patchset #2 id:20001 of https://codereview.chromium.org/2830093002/ )
> 
> Reason for revert:
> Breaks: 
>
https://build.chromium.org/p/client.v8/builders/V8%20Mac%20GC%20Stress/builds...
> and
>
https://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20gc%20stress/...
> 
> Original issue's description:
> > [builtins] DeleteProperty: Handle last-added fast properties
> > 
> > In general, deleting a property from a fast-properties object
> > requires transitioning the object to dictionary mode. However,
> > when the most-recently-added property is deleted, we can simply
> > roll back the last map transition that the object went through.
> > 
> > This is a performance experiment: it should make things faster,
> > but if it turns out to have more negative than positive impact,
> > we will have to revert it.
> > 
> > TBR=bmeurer@chromium.org (just adding a comment)
> > 
> > Review-Url: https://codereview.chromium.org/2830093002
> > Cr-Commit-Position: refs/heads/master@{#44799}
> > Committed:
https://chromium.googlesource.com/v8/v8/+/98acfb36e1acf2ab52ab6b6439eb6356c83...
> 
> TBR=ishell@chromium.org,jkummerow@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> 
> Review-Url: https://codereview.chromium.org/2843473002
> Cr-Commit-Position: refs/heads/master@{#44806}
> Committed:
https://chromium.googlesource.com/v8/v8/+/852a20b08c031690db262e257f87d0bb664...

TBR=ishell@chromium.org,machenbach@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
==========

to

==========
Reland of [builtins] DeleteProperty: Handle last-added fast properties

In general, deleting a property from a fast-properties object
requires transitioning the object to dictionary mode. However,
when the most-recently-added property is deleted, we can simply
roll back the last map transition that the object went through.

This is a performance experiment: it should make things faster,
but if it turns out to have more negative than positive impact,
we will have to revert it.

TBR=bmeurer@chromium.org (just adding a comment)

Previously reviewed at https://codereview.chromium.org/2830093002
Previously landed as 98acfb36e1a / r44799
==========

[Jakob Kummerow, 2017-04-24 15:10:17]

The CQ bit was checked by jkummerow@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-04-24 15:10:25]

Dry run: CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Jakob Kummerow, 2017-04-24 15:11:39]

PTAL. Sorry for the messed-up diff (revert of revert did not imply rebase?);
builtins-internal-gen.cc is the only actual change from patch set 1 -> 2.

[Igor Sheludko, 2017-04-24 15:12:10]

lgtm

[commit-bot: I haz the power, 2017-04-24 15:36:57]

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

[commit-bot: I haz the power, 2017-04-24 15:36:58]

Dry run: This issue passed the CQ dry run.

[Jakob Kummerow, 2017-04-24 15:57:25]

The CQ bit was checked by jkummerow@chromium.org

[commit-bot: I haz the power, 2017-04-24 15:57:27]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-24 15:59:01]

CQ is committing da patch.

Bot data: {"patchset_id": 160001, "attempt_start_ts": 1493049445579560,
"parent_rev": "2c9fc184743dac8627b78a5990522525f35a0007", "commit_rev":
"0f88153075bbc97d4701533454cf11a690ad7210"}

[commit-bot: I haz the power, 2017-04-24 15:59:07]

Description was changed from

==========
Reland of [builtins] DeleteProperty: Handle last-added fast properties

In general, deleting a property from a fast-properties object
requires transitioning the object to dictionary mode. However,
when the most-recently-added property is deleted, we can simply
roll back the last map transition that the object went through.

This is a performance experiment: it should make things faster,
but if it turns out to have more negative than positive impact,
we will have to revert it.

TBR=bmeurer@chromium.org (just adding a comment)

Previously reviewed at https://codereview.chromium.org/2830093002
Previously landed as 98acfb36e1a / r44799
==========

to

==========
Reland of [builtins] DeleteProperty: Handle last-added fast properties

In general, deleting a property from a fast-properties object
requires transitioning the object to dictionary mode. However,
when the most-recently-added property is deleted, we can simply
roll back the last map transition that the object went through.

This is a performance experiment: it should make things faster,
but if it turns out to have more negative than positive impact,
we will have to revert it.

TBR=bmeurer@chromium.org (just adding a comment)

Previously reviewed at https://codereview.chromium.org/2830093002
Previously landed as 98acfb36e1a / r44799

Review-Url: https://codereview.chromium.org/2840583002
Cr-Commit-Position: refs/heads/master@{#44808}
Committed:
https://chromium.googlesource.com/v8/v8/+/0f88153075bbc97d4701533454cf11a690a...
==========

[commit-bot: I haz the power, 2017-04-24 15:59:08]

Committed patchset #2 (id:160001) as
https://chromium.googlesource.com/v8/v8/+/0f88153075bbc97d4701533454cf11a690a...