Revert "[stubs] KeyedLoadGeneric: support loading properties from strings"

Revert "[stubs] KeyedLoadGeneric: support loading properties from strings"

Adding a code path for strings introduces Phi nodes on the fast
(i.e. non-string) path, causing a performance regression.

BUG=chromium:687075
Review-Url: https://codereview.chromium.org/2670353004
Cr-Commit-Position: refs/heads/master@{#42977}
Committed: https://chromium.googlesource.com/v8/v8/+/a5298c6f525cb90c46e8f16966e162f38117c012

[Jakob Kummerow, 2017-02-03 22:34:26]

jkummerow@chromium.org changed reviewers:
+ ishell@chromium.org

[Jakob Kummerow, 2017-02-03 22:34:26]

Unfortunately, the original patch, while making loads from strings significantly
faster, tanks loads from regular objects. Given that downside, doing this is
probably just not worth it at this time.

(A future solution I can think of would be to create an entire separate stub for
slow cases, but that has a memory cost, so we should do it only if there is
evidence that it's worth that price.)

This is a partial revert, keeping the refactoring into separate functions.

Please take a look.

[Igor Sheludko, 2017-02-06 18:03:27]

lgtm

[Jakob Kummerow, 2017-02-07 00:42:12]

The CQ bit was checked by jkummerow@chromium.org

[commit-bot: I haz the power, 2017-02-07 00:42:15]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-02-07 01:05:43]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1486428132905370, "parent_rev":
"a701fce85ee58cb30c68336529f05630cea8c40d", "commit_rev":
"a5298c6f525cb90c46e8f16966e162f38117c012"}

[commit-bot: I haz the power, 2017-02-07 01:05:49]

Description was changed from

==========
Revert "[stubs] KeyedLoadGeneric: support loading properties from strings"

Adding a code path for strings introduces Phi nodes on the fast
(i.e. non-string) path, causing a performance regression.

BUG=chromium:687075
==========

to

==========
Revert "[stubs] KeyedLoadGeneric: support loading properties from strings"

Adding a code path for strings introduces Phi nodes on the fast
(i.e. non-string) path, causing a performance regression.

BUG=chromium:687075

Review-Url: https://codereview.chromium.org/2670353004
Cr-Commit-Position: refs/heads/master@{#42977}
Committed:
https://chromium.googlesource.com/v8/v8/+/a5298c6f525cb90c46e8f16966e162f3811...
==========

[commit-bot: I haz the power, 2017-02-07 01:05:50]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/v8/v8/+/a5298c6f525cb90c46e8f16966e162f3811...