[ignition] BytecodeGraphBuilder: Merge correct environment in try block

[ignition] BytecodeGraphBuilder: Merge correct environment in try block

Making new nodes inside of exception-handled blocks fiddles around with the
current environment to merge the exception paths. In particular, the current
environment pointer is mutated. This patch ensures that when we merge the fast
and slow paths of the LdaContextLookup, we actually merge the correct
environment and do not accidentally merge the exceptional environment.

BUG=chromium:651394
Committed: https://crrev.com/537c855882d14aa868b12f9495b7a0ca8b7a8d40
Cr-Commit-Position: refs/heads/master@{#39878}

[Leszek Swirski, 2016-09-29 14:28:02]

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

[commit-bot: I haz the power, 2016-09-29 14:28:11]

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

[Leszek Swirski, 2016-09-29 14:32:30]

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

[commit-bot: I haz the power, 2016-09-29 14:32:44]

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

[Leszek Swirski, 2016-09-29 14:36:43]

leszeks@chromium.org changed reviewers:
+ mstarzinger@chromium.org

[Michael Starzinger, 2016-09-29 14:41:36]

LGTM.

[Leszek Swirski, 2016-09-29 14:42:38]

The CQ bit was unchecked by leszeks@chromium.org

[Leszek Swirski, 2016-09-29 14:42:39]

The CQ bit was checked by leszeks@chromium.org

[commit-bot: I haz the power, 2016-09-29 14:42:48]

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, 2016-09-29 15:17:56]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-09-29 15:18:13]

Description was changed from

==========
[ignition] BytecodeGraphBuilder: Merge correct environment in try block

Making new nodes inside of exception-handled blocks fiddles around with the
current environment to merge the exception paths. In particular, the current
environment pointer is mutated. This patch ensures that when we merge the fast
and slow paths of the LdaContextLookup, we actually merge the correct
environment and do not accidentally merge the exceptional environment.

BUG=chromium:651394
==========

to

==========
[ignition] BytecodeGraphBuilder: Merge correct environment in try block

Making new nodes inside of exception-handled blocks fiddles around with the
current environment to merge the exception paths. In particular, the current
environment pointer is mutated. This patch ensures that when we merge the fast
and slow paths of the LdaContextLookup, we actually merge the correct
environment and do not accidentally merge the exceptional environment.

BUG=chromium:651394

Committed: https://crrev.com/537c855882d14aa868b12f9495b7a0ca8b7a8d40
Cr-Commit-Position: refs/heads/master@{#39878}
==========

[commit-bot: I haz the power, 2016-09-29 15:18:14]

Patchset 2 (id:??) landed as
https://crrev.com/537c855882d14aa868b12f9495b7a0ca8b7a8d40
Cr-Commit-Position: refs/heads/master@{#39878}