[turbofan] Fix bugs in escape analysis.

[turbofan] Improve escape analysis.

* Treat Select nodes as escaping
* Correctly void virtual field information
  after a store to a non-const index
* Add a shortcut if all allocates escape
* Add a shortcut if no allocates are discovered
* Only reduce FrameState/StateValues nodes if they
  have virtual allocates as input (transitively)
* Fix bug in FrameState/StateValues duplication
* Add check to verifier: First 3 inputs of FrameState
  must be StateValues

R=mstarzinger@chromium.org
BUG=v8:4586
LOG=n

Committed: https://crrev.com/4efbeac115d9d23dc602896684dbb9ef1375142c
Cr-Commit-Position: refs/heads/master@{#33406}

[sigurds, 2016-01-15 10:17:51]

Description was changed from

==========
[turbofan] Fix bugs in escape analysis.

This CL treats Select uses as escaping, and fixes
a bug in the generation of frame states.

R=mstarzinger@chromium.org
BUG=v8:4586
LOG=n
==========

to

==========
[turbofan] Improve escape analysis.

* Treat Select nodes as escaping


R=mstarzinger@chromium.org
BUG=v8:4586
LOG=n
==========

[sigurds, 2016-01-15 10:24:45]

Description was changed from

==========
[turbofan] Improve escape analysis.

* Treat Select nodes as escaping


R=mstarzinger@chromium.org
BUG=v8:4586
LOG=n
==========

to

==========
[turbofan] Improve escape analysis.

* Treat Select nodes as escaping
* Correctly void virtual field information
  after a store to a non-const index
* Add a shortcut if all allocates escape
* Add a shortcut if no allocates are discovered
* Only reduce FrameState/StateValues nodes if they
  have virtual allocates as input (transitively)
* Fix bug in FrameState/StateValues duplication
* Add check to verifier: First 3 inputs of FrameState
  must be StateValues

R=mstarzinger@chromium.org
BUG=v8:4586
LOG=n
==========

[sigurds, 2016-01-18 12:13:16]

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

[sigurds, 2016-01-18 12:13:17]

Thanks for agreeing to review, jarin. I have added some comments to make it more
clear what the changes are.

https://codereview.chromium.org/1583213003/diff/220001/src/compiler/escape-an...
File src/compiler/escape-analysis-reducer.cc (right):

https://codereview.chromium.org/1583213003/diff/220001/src/compiler/escape-an...
src/compiler/escape-analysis-reducer.cc:41: case IrOpcode::kFrameState:
Here we identify FrameStates and StateValues that do not have virtual allocs as
input. Those need not be visited by ReduceDeoptState, and this saves time.

https://codereview.chromium.org/1583213003/diff/220001/src/compiler/escape-an...
src/compiler/escape-analysis-reducer.cc:234: bool node_multiused =
node->UseCount() > 1;
node->UseCount() is /really/ expensive; we just want to do it once.

https://codereview.chromium.org/1583213003/diff/220001/src/compiler/escape-an...
File src/compiler/escape-analysis.cc (right):

https://codereview.chromium.org/1583213003/diff/220001/src/compiler/escape-an...
src/compiler/escape-analysis.cc:1200: return GetVirtualObject(state,
ResolveReplacement(node));
The loop is not necessary since we rely on aliases_ to resolve VirtualObjects
(i.e. kAllocate and kFinishRegion refer to the same VirtualObject)

https://codereview.chromium.org/1583213003/diff/220001/src/compiler/escape-an...
src/compiler/escape-analysis.cc:1318: UpdateReplacement(state, node, nullptr);
This is a critical bug-fix

https://codereview.chromium.org/1583213003/diff/220001/src/flag-definitions.h
File src/flag-definitions.h (right):

https://codereview.chromium.org/1583213003/diff/220001/src/flag-definitions.h...
src/flag-definitions.h:421: DEFINE_IMPLICATION(turbo, turbo_escape)
This is just here for the bots (bots run with escape analysis staged, more
coverage)
I'll remove it before landing this CL and stage via
https://codereview.chromium.org/1587013002/

[Jarin, 2016-01-20 12:59:13]

lgtm. Thanks!

[sigurds, 2016-01-20 13:03:22]

The CQ bit was checked by sigurds@chromium.org

[sigurds, 2016-01-20 13:03:22]

The patchset sent to the CQ was uploaded after l-g-t-m from jarin@chromium.org
Link to the patchset: https://codereview.chromium.org/1583213003/#ps320001
(title: "Unstage")

[commit-bot: I haz the power, 2016-01-20 13:03:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1583213003/320001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1583213003/320001

[commit-bot: I haz the power, 2016-01-20 13:25:25]

Description was changed from

==========
[turbofan] Improve escape analysis.

* Treat Select nodes as escaping
* Correctly void virtual field information
  after a store to a non-const index
* Add a shortcut if all allocates escape
* Add a shortcut if no allocates are discovered
* Only reduce FrameState/StateValues nodes if they
  have virtual allocates as input (transitively)
* Fix bug in FrameState/StateValues duplication
* Add check to verifier: First 3 inputs of FrameState
  must be StateValues

R=mstarzinger@chromium.org
BUG=v8:4586
LOG=n
==========

to

==========
[turbofan] Improve escape analysis.

* Treat Select nodes as escaping
* Correctly void virtual field information
  after a store to a non-const index
* Add a shortcut if all allocates escape
* Add a shortcut if no allocates are discovered
* Only reduce FrameState/StateValues nodes if they
  have virtual allocates as input (transitively)
* Fix bug in FrameState/StateValues duplication
* Add check to verifier: First 3 inputs of FrameState
  must be StateValues

R=mstarzinger@chromium.org
BUG=v8:4586
LOG=n
==========

[commit-bot: I haz the power, 2016-01-20 13:25:26]

Committed patchset #17 (id:320001)

[commit-bot: I haz the power, 2016-01-20 13:26:37]

Description was changed from

==========
[turbofan] Improve escape analysis.

* Treat Select nodes as escaping
* Correctly void virtual field information
  after a store to a non-const index
* Add a shortcut if all allocates escape
* Add a shortcut if no allocates are discovered
* Only reduce FrameState/StateValues nodes if they
  have virtual allocates as input (transitively)
* Fix bug in FrameState/StateValues duplication
* Add check to verifier: First 3 inputs of FrameState
  must be StateValues

R=mstarzinger@chromium.org
BUG=v8:4586
LOG=n
==========

to

==========
[turbofan] Improve escape analysis.

* Treat Select nodes as escaping
* Correctly void virtual field information
  after a store to a non-const index
* Add a shortcut if all allocates escape
* Add a shortcut if no allocates are discovered
* Only reduce FrameState/StateValues nodes if they
  have virtual allocates as input (transitively)
* Fix bug in FrameState/StateValues duplication
* Add check to verifier: First 3 inputs of FrameState
  must be StateValues

R=mstarzinger@chromium.org
BUG=v8:4586
LOG=n

Committed: https://crrev.com/4efbeac115d9d23dc602896684dbb9ef1375142c
Cr-Commit-Position: refs/heads/master@{#33406}
==========

[commit-bot: I haz the power, 2016-01-20 13:26:37]

Patchset 17 (id:??) landed as
https://crrev.com/4efbeac115d9d23dc602896684dbb9ef1375142c
Cr-Commit-Position: refs/heads/master@{#33406}