[turbofan] Optimized lowering of DYNAMIC_LOCAL lookup slot loads.

[turbofan] Optimized lowering of DYNAMIC_LOCAL lookup slot loads.

This adds handling of JSLoadDynamicContext nodes to JSTypedLowering to
perform extension checks and an inline fast path. The fast path is a
context slot load targeting a specific context.

R=bmeurer@chromium.org
BUG=v8:4131
LOG=N

Committed: https://crrev.com/5ca1f24dd51fb2b3202dda4ee23a7b833dd352a9
Cr-Commit-Position: refs/heads/master@{#28823}

[Benedikt Meurer, 2015-06-03 03:46:53]

https://codereview.chromium.org/1155543003/diff/20001/src/compiler/js-typed-l...
File src/compiler/js-typed-lowering.cc (right):

https://codereview.chromium.org/1155543003/diff/20001/src/compiler/js-typed-l...
src/compiler/js-typed-lowering.cc:1003: Node* check =
graph()->NewNode(simplified()->ObjectIsSmi(), load);
We can use ReferenceEqual to zero here, see
https://codereview.chromium.org/1163963003/ for details.

[Michael Starzinger, 2015-06-03 08:45:00]

https://codereview.chromium.org/1155543003/diff/20001/src/compiler/js-typed-l...
File src/compiler/js-typed-lowering.cc (right):

https://codereview.chromium.org/1155543003/diff/20001/src/compiler/js-typed-l...
src/compiler/js-typed-lowering.cc:1003: Node* check =
graph()->NewNode(simplified()->ObjectIsSmi(), load);
On 2015/06/03 03:46:52, Benedikt Meurer wrote:
> We can use ReferenceEqual to zero here, see
> https://codereview.chromium.org/1163963003/ for details.

Done.

[Benedikt Meurer, 2015-06-08 08:18:25]

The CQ bit was checked by bmeurer@chromium.org

[Benedikt Meurer, 2015-06-08 08:18:25]

lgtm

[commit-bot: I haz the power, 2015-06-08 08:18:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1155543003/40001

[commit-bot: I haz the power, 2015-06-08 08:59:05]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-06-08 08:59:12]

Patchset 3 (id:??) landed as
https://crrev.com/5ca1f24dd51fb2b3202dda4ee23a7b833dd352a9
Cr-Commit-Position: refs/heads/master@{#28823}