PPC: [fullcodegen] Implement operand stack depth tracking.

PPC: [fullcodegen] Implement operand stack depth tracking.

Port 38915ed71c179276a1368ea8442bf88f66f50a4c

Original commit message:
    This implements a mechanism to track the exact depth of the operand
    stack in full-codegen for every sub-expression visitation. So far we
    only tracked the depth at statement level, but not at expression level.
    With the introduction of do-expressions it will be possible to construct
    local control flow (i.e. break, continue and friends) that target labels
    at an arbitrary operand stack depth, making this tracking a prerequisite
    for full do-expression support.

R=mstarzinger@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=v8:4755, v8:4488
LOG=n

Committed: https://crrev.com/b3de78c191420d0c9c9883c2065e0185f9591594
Cr-Commit-Position: refs/heads/master@{#34227}

[MTBrandyberry, 2016-02-23 19:38:43]

The CQ bit was checked by mbrandy@us.ibm.com to run a CQ dry run

[commit-bot: I haz the power, 2016-02-23 19:38:46]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1729613002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1729613002/1

[Michael Starzinger, 2016-02-23 19:42:20]

LGTM. Thanks!

[commit-bot: I haz the power, 2016-02-23 20:02:51]

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

[commit-bot: I haz the power, 2016-02-23 20:02:51]

Dry run: This issue passed the CQ dry run.

[MTBrandyberry, 2016-02-23 20:06:31]

The CQ bit was checked by mbrandy@us.ibm.com

[commit-bot: I haz the power, 2016-02-23 20:06:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1729613002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1729613002/1

[commit-bot: I haz the power, 2016-02-23 20:08:12]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-02-23 20:09:49]

Description was changed from

==========
PPC: [fullcodegen] Implement operand stack depth tracking.

Port 38915ed71c179276a1368ea8442bf88f66f50a4c

Original commit message:
    This implements a mechanism to track the exact depth of the operand
    stack in full-codegen for every sub-expression visitation. So far we
    only tracked the depth at statement level, but not at expression level.
    With the introduction of do-expressions it will be possible to construct
    local control flow (i.e. break, continue and friends) that target labels
    at an arbitrary operand stack depth, making this tracking a prerequisite
    for full do-expression support.

R=mstarzinger@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com,
michael_dawson@ca.ibm.com
BUG=v8:4755,v8:4488
LOG=n
==========

to

==========
PPC: [fullcodegen] Implement operand stack depth tracking.

Port 38915ed71c179276a1368ea8442bf88f66f50a4c

Original commit message:
    This implements a mechanism to track the exact depth of the operand
    stack in full-codegen for every sub-expression visitation. So far we
    only tracked the depth at statement level, but not at expression level.
    With the introduction of do-expressions it will be possible to construct
    local control flow (i.e. break, continue and friends) that target labels
    at an arbitrary operand stack depth, making this tracking a prerequisite
    for full do-expression support.

R=mstarzinger@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com,
michael_dawson@ca.ibm.com
BUG=v8:4755,v8:4488
LOG=n

Committed: https://crrev.com/b3de78c191420d0c9c9883c2065e0185f9591594
Cr-Commit-Position: refs/heads/master@{#34227}
==========

[commit-bot: I haz the power, 2016-02-23 20:09:50]

Patchset 1 (id:??) landed as
https://crrev.com/b3de78c191420d0c9c9883c2065e0185f9591594
Cr-Commit-Position: refs/heads/master@{#34227}