[turbofan] Refactor the OSR environment merging to create an explicit environment.

[turbofan] Refactor the OSR environment merging to create an explicit environment.

This is useful for my upcoming work on OSR typing, which needs
to create checkpoints (which in turn require environments).

Committed: https://crrev.com/ff7e60c869c80c0b2fd20a35b0a01c6a46aec40c
Cr-Commit-Position: refs/heads/master@{#39869}

[Jarin, 2016-09-29 10:01:25]

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

[commit-bot: I haz the power, 2016-09-29 10:01:30]

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

[Jarin, 2016-09-29 10:02:58]

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

[Jarin, 2016-09-29 10:02:59]

Could you take a look, please?

If this is well received, I will do the same in the bytecode graph builder.

[commit-bot: I haz the power, 2016-09-29 10:28:01]

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

[commit-bot: I haz the power, 2016-09-29 10:28:02]

Dry run: This issue passed the CQ dry run.

[Michael Starzinger, 2016-09-29 13:14:35]

I like it. I think this approach is cleaner than what was there before. Just one
suggestion.

https://codereview.chromium.org/2379643003/diff/1/src/compiler/ast-graph-buil...
File src/compiler/ast-graph-builder.cc (right):

https://codereview.chromium.org/2379643003/diff/1/src/compiler/ast-graph-buil...
src/compiler/ast-graph-builder.cc:4194: AstGraphBuilder::Environment*
AstGraphBuilder::Environment::PrepareOsrEntry() {
As discussed offline: This function creates a copy of {this} and then only
mutates the copy. We could enforce this inteded behavior by instead making this
function only work on {this} and invoking it as follows ...

Environmet* osr_entry = CopyForOsrEntry();
osr_entry->PrepareForOsrEntry();
loop->Merge(osr_entry);

This method would then return {void} similar to the existing {PrepareForLoop}
method. IMHO that would keep things uniform. WDYT?

[Jarin, 2016-09-29 13:24:23]

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

[commit-bot: I haz the power, 2016-09-29 13:24:30]

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

[Jarin, 2016-09-29 13:40:25]

https://codereview.chromium.org/2379643003/diff/1/src/compiler/ast-graph-buil...
File src/compiler/ast-graph-builder.cc (right):

https://codereview.chromium.org/2379643003/diff/1/src/compiler/ast-graph-buil...
src/compiler/ast-graph-builder.cc:4194: AstGraphBuilder::Environment*
AstGraphBuilder::Environment::PrepareOsrEntry() {
On 2016/09/29 13:14:34, Michael Starzinger wrote:
> As discussed offline: This function creates a copy of {this} and then only
> mutates the copy. We could enforce this inteded behavior by instead making
this
> function only work on {this} and invoking it as follows ...
> 
> Environmet* osr_entry = CopyForOsrEntry();
> osr_entry->PrepareForOsrEntry();
> loop->Merge(osr_entry);
> 
> This method would then return {void} similar to the existing {PrepareForLoop}
> method. IMHO that would keep things uniform. WDYT?

Done. Thanks!

[Jarin, 2016-09-29 13:40:30]

The CQ bit was unchecked by jarin@chromium.org

[Jarin, 2016-09-29 13:40:31]

The CQ bit was checked by jarin@chromium.org

[commit-bot: I haz the power, 2016-09-29 13:40:41]

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 13:40:42]

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

[commit-bot: I haz the power, 2016-09-29 13:40:43]

No L-G-T-M from a valid reviewer yet. 
CQ run can only be started by full committers or once the patch has
received an L-G-T-M from a full committer.
Even if an L-G-T-M may have been provided, it was from a non-committer,
_not_ a full super star committer.
Committers are members of the group "project-v8-committers".
Note that this has nothing to do with OWNERS files.

[Michael Starzinger, 2016-09-29 13:42:06]

LGTM. Thanks!

[Jarin, 2016-09-29 13:48:44]

The CQ bit was checked by jarin@chromium.org

[commit-bot: I haz the power, 2016-09-29 13:48:51]

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 13:56:05]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-09-29 13:56:22]

Description was changed from

==========
[turbofan] Refactor the OSR environment merging to create an explicit
environment.

This is useful for my upcoming work on OSR typing, which needs
to create checkpoints (which in turn require environments).
==========

to

==========
[turbofan] Refactor the OSR environment merging to create an explicit
environment.

This is useful for my upcoming work on OSR typing, which needs
to create checkpoints (which in turn require environments).

Committed: https://crrev.com/ff7e60c869c80c0b2fd20a35b0a01c6a46aec40c
Cr-Commit-Position: refs/heads/master@{#39869}
==========

[commit-bot: I haz the power, 2016-09-29 13:56:23]

Patchset 2 (id:??) landed as
https://crrev.com/ff7e60c869c80c0b2fd20a35b0a01c6a46aec40c
Cr-Commit-Position: refs/heads/master@{#39869}