MIPS64: [fullcodegen] Implement operand stack depth tracking.

MIPS64: [fullcodegen] Implement operand stack depth tracking.

Port for https://codereview.chromium.org/1706283002/

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.

BUG=v8:4755, v8:4488
LOG=n

[balazs.kilvady, 2016-02-23 12:38:26]

Description was changed from

==========
MIPS64: [fullcodegen] Implement operand stack depth tracking.

Port for https://codereview.chromium.org/1706283002/

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=rossberg@chromium.org,jarin@chromium.org
BUG=v8:4755,v8:4488
LOG=n
==========

to

==========
MIPS64: [fullcodegen] Implement operand stack depth tracking.

Port for https://codereview.chromium.org/1706283002/

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.

BUG=v8:4755,v8:4488
LOG=n
==========

[balazs.kilvady, 2016-02-23 12:38:27]

balazs.kilvady@imgtec.com changed reviewers:
- jarin@chromium.org, rossberg@chromium.org

[balazs.kilvady, 2016-02-23 12:39:45]

balazs.kilvady@imgtec.com changed reviewers:
+ akos.palfi@imgtec.com, ivica.bogosavljevic@imgtec.com,
mstarzinger@chromium.org