Ensure IteratorClose is called for errors in non-declaring assignments

Ensure IteratorClose is called for errors in non-declaring assignments

There was a bug in for-of loops without newly declared variables: If,
in performing the assignment, an exception were thrown, then
IteratorClose would not be called. The problem was that the assignment
is done as part of assign_each, which happens before the loop is put
back in the state which is recognized to be breaking/throwing/returning
early.

This patch modifies the for-of desugaring by setting the loop state
before, rather than after, evaluating the assign_each portion, which is
responsible for evaluating the assignment in for-of loops which do not
have a declaration.

This patch, together with https://codereview.chromium.org/1728973002 ,
allow all test262 iterator return-related tests to pass.

R=rossberg
BUG=v8:4776
LOG=Y

Committed: https://crrev.com/1aee75551ea3237ab653a998e492110e50f18cdd
Cr-Commit-Position: refs/heads/master@{#34262}

[Dan Ehrenberg, 2016-02-24 06:55:20]

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

[commit-bot: I haz the power, 2016-02-24 06:55:35]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1731773003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1731773003/1

[Dan Ehrenberg, 2016-02-24 06:59:06]

This is still a work in progress, as the error thrown from the test case that's
added is a mysterious other kind of error from what I expected, but I'd be
interested in design feedback. There are a number of different places that could
have been modified to move the assignment to, but this one seemed the cleanest.

[commit-bot: I haz the power, 2016-02-24 07:08:21]

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

[commit-bot: I haz the power, 2016-02-24 07:08:22]

Dry run: Try jobs failed on following builders:
  v8_mac_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_mac_rel/builds/15906)

[rossberg, 2016-02-24 11:29:48]

Nice, lgtm, modulo the remaining bug. Thanks!

[Dan Ehrenberg, 2016-02-24 18:26:56]

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

[Dan Ehrenberg, 2016-02-24 18:26:56]

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

[Dan Ehrenberg, 2016-02-24 18:26:57]

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

[commit-bot: I haz the power, 2016-02-24 18:27:01]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1731773003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1731773003/40001

[Dan Ehrenberg, 2016-02-24 18:28:22]

On 2016/02/24 at 11:29:48, rossberg wrote:
> Nice, lgtm, modulo the remaining bug. Thanks!

Fixed the issue (I had failed to allocate the variable that the do-expression
was using).

[Dan Ehrenberg, 2016-02-24 18:43:14]

The CQ bit was unchecked by littledan@chromium.org

[Dan Ehrenberg, 2016-02-24 18:43:16]

The CQ bit was checked by littledan@chromium.org

[Dan Ehrenberg, 2016-02-24 18:43:16]

The patchset sent to the CQ was uploaded after l-g-t-m from
rossberg@chromium.org
Link to the patchset: https://codereview.chromium.org/1731773003/#ps40001
(title: "Rebase and fix test262 expectation")

[commit-bot: I haz the power, 2016-02-24 18:43:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1731773003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1731773003/40001

[commit-bot: I haz the power, 2016-02-24 18:52:22]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-02-24 18:52:33]

Description was changed from

==========
Ensure IteratorClose is called for errors in non-declaring assignments

There was a bug in for-of loops without newly declared variables: If,
in performing the assignment, an exception were thrown, then
IteratorClose would not be called. The problem was that the assignment
is done as part of assign_each, which happens before the loop is put
back in the state which is recognized to be breaking/throwing/returning
early.

This patch modifies the for-of desugaring by setting the loop state
before, rather than after, evaluating the assign_each portion, which is
responsible for evaluating the assignment in for-of loops which do not
have a declaration.

This patch, together with https://codereview.chromium.org/1728973002 ,
allow all test262 iterator return-related tests to pass.

R=rossberg
BUG=v8:4776
LOG=Y
==========

to

==========
Ensure IteratorClose is called for errors in non-declaring assignments

There was a bug in for-of loops without newly declared variables: If,
in performing the assignment, an exception were thrown, then
IteratorClose would not be called. The problem was that the assignment
is done as part of assign_each, which happens before the loop is put
back in the state which is recognized to be breaking/throwing/returning
early.

This patch modifies the for-of desugaring by setting the loop state
before, rather than after, evaluating the assign_each portion, which is
responsible for evaluating the assignment in for-of loops which do not
have a declaration.

This patch, together with https://codereview.chromium.org/1728973002 ,
allow all test262 iterator return-related tests to pass.

R=rossberg
BUG=v8:4776
LOG=Y

Committed: https://crrev.com/1aee75551ea3237ab653a998e492110e50f18cdd
Cr-Commit-Position: refs/heads/master@{#34262}
==========

[commit-bot: I haz the power, 2016-02-24 18:52:35]

Patchset 3 (id:??) landed as
https://crrev.com/1aee75551ea3237ab653a998e492110e50f18cdd
Cr-Commit-Position: refs/heads/master@{#34262}