Add flag for disallowing for-in initializers

Add flag for disallowing for-in initializers

This does not affect use counters.

R=nikolaos@chromium.org
BUG=

Committed: https://crrev.com/9ce87d67728d671a3ae11bf2befb1d92936e22b7
Cr-Commit-Position: refs/heads/master@{#35726}

[nickie, 2016-04-22 11:22:56]

LGTM, modulo the inconsistency with the preparser that we discussed.

https://codereview.chromium.org/1911963003/diff/1/src/parsing/parser.cc
File src/parsing/parser.cc (right):

https://codereview.chromium.org/1911963003/diff/1/src/parsing/parser.cc#newco...
src/parsing/parser.cc:3503: if (FLAG_harmony_for_in) {
Shouldn't a similar thing be added to the preparser?

[rossberg, 2016-04-22 11:34:50]

https://codereview.chromium.org/1911963003/diff/1/src/parsing/parser.cc
File src/parsing/parser.cc (right):

https://codereview.chromium.org/1911963003/diff/1/src/parsing/parser.cc#newco...
src/parsing/parser.cc:3503: if (FLAG_harmony_for_in) {
On 2016/04/22 11:22:56, nickie wrote:
> Shouldn't a similar thing be added to the preparser?

Yes, normally it should. However, we'd lose use counts if we already rejected it
in the preparser. So I'm inclined to leave it like that as a temporary measure.
I added a TODO comment explaining this.

[rossberg, 2016-04-22 11:34:55]

The CQ bit was checked by rossberg@chromium.org

[rossberg, 2016-04-22 11:34:55]

The patchset sent to the CQ was uploaded after l-g-t-m from
nikolaos@chromium.org
Link to the patchset: https://codereview.chromium.org/1911963003/#ps20001
(title: "Added comment")

[commit-bot: I haz the power, 2016-04-22 11:35:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1911963003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1911963003/20001

[commit-bot: I haz the power, 2016-04-22 12:02:56]

Committed patchset #2 (id:20001)

[adamk, 2016-04-22 17:28:17]

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

[adamk, 2016-04-22 17:28:18]

https://codereview.chromium.org/1911963003/diff/1/src/parsing/parser.cc
File src/parsing/parser.cc (right):

https://codereview.chromium.org/1911963003/diff/1/src/parsing/parser.cc#newco...
src/parsing/parser.cc:3503: if (FLAG_harmony_for_in) {
On 2016/04/22 11:34:50, rossberg wrote:
> On 2016/04/22 11:22:56, nickie wrote:
> > Shouldn't a similar thing be added to the preparser?
> 
> Yes, normally it should. However, we'd lose use counts if we already rejected
it
> in the preparser. So I'm inclined to leave it like that as a temporary
measure.
> I added a TODO comment explaining this.

This inconsistency seems like it'll cause us some headaches if people actually
start reporting bugs about this feature. You could instead add a bit of API to
the ParserRecorder and copy that over to the use_counts_ in
ParseLazyFunctionBodyWithPreParser. If you feel that's too complex for this
feature, than I'd rather lose the UseCounter data then have this inconsistency
in behavior.

[adamk, 2016-04-22 18:23:54]

On 2016/04/22 17:28:18, adamk wrote:
> https://codereview.chromium.org/1911963003/diff/1/src/parsing/parser.cc
> File src/parsing/parser.cc (right):
> 
>
https://codereview.chromium.org/1911963003/diff/1/src/parsing/parser.cc#newco...
> src/parsing/parser.cc:3503: if (FLAG_harmony_for_in) {
> On 2016/04/22 11:34:50, rossberg wrote:
> > On 2016/04/22 11:22:56, nickie wrote:
> > > Shouldn't a similar thing be added to the preparser?
> > 
> > Yes, normally it should. However, we'd lose use counts if we already
rejected
> it
> > in the preparser. So I'm inclined to leave it like that as a temporary
> measure.
> > I added a TODO comment explaining this.
> 
> This inconsistency seems like it'll cause us some headaches if people actually
> start reporting bugs about this feature. You could instead add a bit of API to
> the ParserRecorder and copy that over to the use_counts_ in
> ParseLazyFunctionBodyWithPreParser. If you feel that's too complex for this
> feature, than I'd rather lose the UseCounter data then have this inconsistency
> in behavior.

Proposed approach here: https://codereview.chromium.org/1913203002/

[commit-bot: I haz the power, 2016-04-22 19:15:30]

Description was changed from

==========
Add flag for disallowing for-in initializers

This does not affect use counters.

R=nikolaos@chromium.org
BUG=
==========

to

==========
Add flag for disallowing for-in initializers

This does not affect use counters.

R=nikolaos@chromium.org
BUG=

Committed: https://crrev.com/9ce87d67728d671a3ae11bf2befb1d92936e22b7
Cr-Commit-Position: refs/heads/master@{#35726}
==========

[commit-bot: I haz the power, 2016-04-22 19:15:31]

Patchset 2 (id:??) landed as
https://crrev.com/9ce87d67728d671a3ae11bf2befb1d92936e22b7
Cr-Commit-Position: refs/heads/master@{#35726}

[rossberg, 2016-04-25 11:42:45]

@adamk, I had considered that, but then we would count the feature twice most of
the time. But I suppose that's not a problem, since we mostly slice counters by
page anyway.