X87: [runtime] Use "the hole" instead of smi 0 as sentinel for context extension.

X87: [runtime] Use "the hole" instead of smi 0 as sentinel for context extension.

  port 9e6448813d41858c3f879ecde41b13bda0770673 (r32407)

  original commit message:
  This way we avoid the %_IsSmi magic that is required in TurboFan to
  (efficiently) check abitrary context slots for smi 0. Checking against
  "the hole" is common in the AstGraphBuilder and "the hole" is also used
  to mark other context slots as not initialized.

BUG=

Committed: https://crrev.com/a8b2d9a18f2bf98cf9beca0ed85cb864d13f0700
Cr-Commit-Position: refs/heads/master@{#32441}

[zhengxing.li, 2015-12-01 02:38:25]

zhengxing.li@intel.com changed reviewers:
+ bmeurer@chromium.org, chunyang.dai@intel.com, weiliang.lin@intel.com

[Weiliang, 2015-12-01 06:19:38]

The CQ bit was checked by weiliang.lin@intel.com

[Weiliang, 2015-12-01 06:19:39]

lgtm

[commit-bot: I haz the power, 2015-12-01 06:19:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1486913002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1486913002/1

[commit-bot: I haz the power, 2015-12-01 06:39:03]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-12-01 06:39:11]

Description was changed from

==========
X87: [runtime] Use "the hole" instead of smi 0 as sentinel for context
extension.

  port 9e6448813d41858c3f879ecde41b13bda0770673 (r32407)

  original commit message:
  This way we avoid the %_IsSmi magic that is required in TurboFan to
  (efficiently) check abitrary context slots for smi 0. Checking against
  "the hole" is common in the AstGraphBuilder and "the hole" is also used
  to mark other context slots as not initialized.

BUG=
==========

to

==========
X87: [runtime] Use "the hole" instead of smi 0 as sentinel for context
extension.

  port 9e6448813d41858c3f879ecde41b13bda0770673 (r32407)

  original commit message:
  This way we avoid the %_IsSmi magic that is required in TurboFan to
  (efficiently) check abitrary context slots for smi 0. Checking against
  "the hole" is common in the AstGraphBuilder and "the hole" is also used
  to mark other context slots as not initialized.

BUG=

Committed: https://crrev.com/a8b2d9a18f2bf98cf9beca0ed85cb864d13f0700
Cr-Commit-Position: refs/heads/master@{#32441}
==========

[commit-bot: I haz the power, 2015-12-01 06:39:12]

Patchset 1 (id:??) landed as
https://crrev.com/a8b2d9a18f2bf98cf9beca0ed85cb864d13f0700
Cr-Commit-Position: refs/heads/master@{#32441}