[debugger] Don't leak holes from generator arguments.

[debugger] Don't leak holes from generator arguments.

This is a quick fix for the hole leaking from generators via the debugger's frame
inspection feature: when collecting the arguments, convert each hole to undefined.
In the long term, we probably want to remember and restore the actual arguments
rather than pushing these dummy arguments on each resume.

BUG=v8:5164
Committed: https://crrev.com/45a8167477bee1ce22b204c30d6cb1509763177a
Cr-Commit-Position: refs/heads/master@{#37544}

[neis, 2016-07-05 14:39:44]

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

[commit-bot: I haz the power, 2016-07-05 14:39:54]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[neis, 2016-07-05 14:40:02]

Description was changed from

==========
[generators] When pushing dummy arguments, use undefined rather than the hole.

This is quick fix for the hole leaking from generators via the debugger's frame
inspection feature.  In the long term, we probably want to remember and restore
the actual arguments rather than pushing these dummy arguments on each resume.

BUG=v8:5164
==========

to

==========
[generators] When pushing dummy arguments, use undefined rather than the hole.

This is a quick fix for the hole leaking from generators via the debugger's
frame
inspection feature.  In the long term, we probably want to remember and restore
the actual arguments rather than pushing these dummy arguments on each resume.

BUG=v8:5164
==========

[neis, 2016-07-05 14:42:00]

neis@chromium.org changed reviewers:
+ mstarzinger@chromium.org, yangguo@chromium.org

[neis, 2016-07-05 14:42:56]

ptal

[Michael Starzinger, 2016-07-05 14:52:37]

Instead of pushing "undefined" onto the stack I would actually prefer to convert
the existing holes into undefined when we read them out in the debugger. IIUC
this is going through {FrameInspector::MaterializeStackLocals} and
{Runtime_GetFrameDetails}, which are the two call-sites to
{FrameInspector::GetParameter} correct? Otherwise other such issues where we
look at the parameters to a generator would go unnoticed and fail silently.
Keeping "the_hole" there will make sure we notice when some component
erroneously looks at the values.

[commit-bot: I haz the power, 2016-07-05 14:55:44]

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

[commit-bot: I haz the power, 2016-07-05 14:55:45]

Dry run: Try jobs failed on following builders:
  v8_linux_nodcheck_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_nodcheck_rel_ng/bu...)
  v8_linux_nodcheck_rel_ng_triggered on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_nodcheck_rel_ng_tr...)
  v8_mac_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_mac_rel_ng/builds/4471)
  v8_mac_rel_ng_triggered on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_mac_rel_ng_triggered/bui...)

[Yang, 2016-07-06 05:55:56]

On 2016/07/05 14:52:37, Michael Starzinger wrote:
> Instead of pushing "undefined" onto the stack I would actually prefer to
convert
> the existing holes into undefined when we read them out in the debugger. IIUC
> this is going through {FrameInspector::MaterializeStackLocals} and
> {Runtime_GetFrameDetails}, which are the two call-sites to
> {FrameInspector::GetParameter} correct? Otherwise other such issues where we
> look at the parameters to a generator would go unnoticed and fail silently.
> Keeping "the_hole" there will make sure we notice when some component
> erroneously looks at the values.

Debug-evaluate simply uses Accessors::FunctionGetArguments to get the arguments.

[neis, 2016-07-06 07:16:30]

Description was changed from

==========
[generators] When pushing dummy arguments, use undefined rather than the hole.

This is a quick fix for the hole leaking from generators via the debugger's
frame
inspection feature.  In the long term, we probably want to remember and restore
the actual arguments rather than pushing these dummy arguments on each resume.

BUG=v8:5164
==========

to

==========
[debugger] Don't leak holes from generator arguments.

This is a quick fix for the hole leaking from generators via the debugger's
frame
inspection feature: when collecting the arguments, convert each hole to
undefined. In the long term, we probably want to remember and restore
the actual arguments rather than pushing these dummy arguments on each resume.

BUG=v8:5164
==========

[neis, 2016-07-06 07:16:43]

Description was changed from

==========
[debugger] Don't leak holes from generator arguments.

This is a quick fix for the hole leaking from generators via the debugger's
frame
inspection feature: when collecting the arguments, convert each hole to
undefined. In the long term, we probably want to remember and restore
the actual arguments rather than pushing these dummy arguments on each resume.

BUG=v8:5164
==========

to

==========
[debugger] Don't leak holes from generator arguments.

This is a quick fix for the hole leaking from generators via the debugger's
frame
inspection feature: when collecting the arguments, convert each hole to
undefined.
In the long term, we probably want to remember and restore
the actual arguments rather than pushing these dummy arguments on each resume.

BUG=v8:5164
==========

[neis, 2016-07-06 07:17:00]

Description was changed from

==========
[debugger] Don't leak holes from generator arguments.

This is a quick fix for the hole leaking from generators via the debugger's
frame
inspection feature: when collecting the arguments, convert each hole to
undefined.
In the long term, we probably want to remember and restore
the actual arguments rather than pushing these dummy arguments on each resume.

BUG=v8:5164
==========

to

==========
[debugger] Don't leak holes from generator arguments.

This is a quick fix for the hole leaking from generators via the debugger's
frame
inspection feature: when collecting the arguments, convert each hole to
undefined.
In the long term, we probably want to remember and restore the actual arguments
rather than pushing these dummy arguments on each resume.

BUG=v8:5164
==========

[neis, 2016-07-06 07:18:52]

PTanotherL

[Michael Starzinger, 2016-07-06 07:43:07]

LGTM.

[Yang, 2016-07-06 07:44:07]

On 2016/07/06 07:43:07, Michael Starzinger wrote:
> LGTM.

LGTM. Thanks!

[neis, 2016-07-06 07:45:28]

The CQ bit was checked by neis@chromium.org

[commit-bot: I haz the power, 2016-07-06 07:45:38]

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, 2016-07-06 08:10:14]

Description was changed from

==========
[debugger] Don't leak holes from generator arguments.

This is a quick fix for the hole leaking from generators via the debugger's
frame
inspection feature: when collecting the arguments, convert each hole to
undefined.
In the long term, we probably want to remember and restore the actual arguments
rather than pushing these dummy arguments on each resume.

BUG=v8:5164
==========

to

==========
[debugger] Don't leak holes from generator arguments.

This is a quick fix for the hole leaking from generators via the debugger's
frame
inspection feature: when collecting the arguments, convert each hole to
undefined.
In the long term, we probably want to remember and restore the actual arguments
rather than pushing these dummy arguments on each resume.

BUG=v8:5164
==========

[commit-bot: I haz the power, 2016-07-06 08:10:16]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-07-06 08:10:18]

CQ bit was unchecked.

[commit-bot: I haz the power, 2016-07-06 08:11:43]

Description was changed from

==========
[debugger] Don't leak holes from generator arguments.

This is a quick fix for the hole leaking from generators via the debugger's
frame
inspection feature: when collecting the arguments, convert each hole to
undefined.
In the long term, we probably want to remember and restore the actual arguments
rather than pushing these dummy arguments on each resume.

BUG=v8:5164
==========

to

==========
[debugger] Don't leak holes from generator arguments.

This is a quick fix for the hole leaking from generators via the debugger's
frame
inspection feature: when collecting the arguments, convert each hole to
undefined.
In the long term, we probably want to remember and restore the actual arguments
rather than pushing these dummy arguments on each resume.

BUG=v8:5164

Committed: https://crrev.com/45a8167477bee1ce22b204c30d6cb1509763177a
Cr-Commit-Position: refs/heads/master@{#37544}
==========

[commit-bot: I haz the power, 2016-07-06 08:11:45]

Patchset 3 (id:??) landed as
https://crrev.com/45a8167477bee1ce22b204c30d6cb1509763177a
Cr-Commit-Position: refs/heads/master@{#37544}