[compiler] Introduce StringEqualStub and StringNotEqualStub.

[compiler] Introduce StringEqualStub and StringNotEqualStub.

These new stubs perform exactly the same job as the string equality case
for the CompareIC, but are platform independent and usable outside of
fullcodegen and Crankshaft. We use them in the StrictEqualStub and the
StrictNotEqualStub instead of falling back to the runtime immediately
for String comparisons, and we also use them in TurboFan to perform
String equality or inequality comparisons.

These stubs currently handle only internalized and one byte strings w/o
going to C++, but it should be easy to add support for more string cases
later, i.e. utilizing already flattened cons strings or comparing two
byte strings as well.

Committed: https://crrev.com/2689548e38c68bb6294fed5e2d83feec67e3a1f4
Cr-Commit-Position: refs/heads/master@{#34459}

[Benedikt Meurer, 2016-03-03 09:19:57]

bmeurer@chromium.org changed reviewers:
+ epertoso@chromium.org

[Benedikt Meurer, 2016-03-03 09:19:58]

Hey Enrico,

Moving more parts to TurboFan code stubs.
Please take a look.

Thanks,
Benedikt

[epertoso, 2016-03-03 09:41:45]

lgtm

https://codereview.chromium.org/1761823002/diff/1/src/code-stubs.cc
File src/code-stubs.cc (right):

https://codereview.chromium.org/1761823002/diff/1/src/code-stubs.cc#newcode711
src/code-stubs.cc:711: Callable callable = (mode == kDontNegateResult)
Does the TODO above still apply?

https://codereview.chromium.org/1761823002/diff/1/src/code-stubs.cc#newcode905
src/code-stubs.cc:905: ? MachineRepresentation::kWord64
nit: MachineType::PointerRepresentation() does this for you.

[Benedikt Meurer, 2016-03-03 09:45:08]

https://codereview.chromium.org/1761823002/diff/1/src/code-stubs.cc
File src/code-stubs.cc (right):

https://codereview.chromium.org/1761823002/diff/1/src/code-stubs.cc#newcode711
src/code-stubs.cc:711: Callable callable = (mode == kDontNegateResult)
On 2016/03/03 09:41:45, epertoso wrote:
> Does the TODO above still apply?

Done.

https://codereview.chromium.org/1761823002/diff/1/src/code-stubs.cc#newcode905
src/code-stubs.cc:905: ? MachineRepresentation::kWord64
On 2016/03/03 09:41:45, epertoso wrote:
> nit: MachineType::PointerRepresentation() does this for you.

Done.

[Benedikt Meurer, 2016-03-03 09:45:13]

The CQ bit was checked by bmeurer@chromium.org

[Benedikt Meurer, 2016-03-03 09:45:13]

The patchset sent to the CQ was uploaded after l-g-t-m from
epertoso@chromium.org
Link to the patchset: https://codereview.chromium.org/1761823002/#ps20001
(title: "Address feedback.")

[commit-bot: I haz the power, 2016-03-03 09:45:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1761823002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1761823002/20001

[commit-bot: I haz the power, 2016-03-03 09:49:34]

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

[commit-bot: I haz the power, 2016-03-03 09:49:35]

Try jobs failed on following builders:
  v8_linux_arm_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm_rel/builds/14687)

[Benedikt Meurer, 2016-03-03 09:51:26]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2016-03-03 09:51:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1761823002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1761823002/20001

[commit-bot: I haz the power, 2016-03-03 10:10:38]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-03-03 10:18:56]

Description was changed from

==========
[compiler] Introduce StringEqualStub and StringNotEqualStub.

These new stubs perform exactly the same job as the string equality case
for the CompareIC, but are platform independent and usable outside of
fullcodegen and Crankshaft. We use them in the StrictEqualStub and the
StrictNotEqualStub instead of falling back to the runtime immediately
for String comparisons, and we also use them in TurboFan to perform
String equality or inequality comparisons.

These stubs currently handle only internalized and one byte strings w/o
going to C++, but it should be easy to add support for more string cases
later, i.e. utilizing already flattened cons strings or comparing two
byte strings as well.
==========

to

==========
[compiler] Introduce StringEqualStub and StringNotEqualStub.

These new stubs perform exactly the same job as the string equality case
for the CompareIC, but are platform independent and usable outside of
fullcodegen and Crankshaft. We use them in the StrictEqualStub and the
StrictNotEqualStub instead of falling back to the runtime immediately
for String comparisons, and we also use them in TurboFan to perform
String equality or inequality comparisons.

These stubs currently handle only internalized and one byte strings w/o
going to C++, but it should be easy to add support for more string cases
later, i.e. utilizing already flattened cons strings or comparing two
byte strings as well.

Committed: https://crrev.com/2689548e38c68bb6294fed5e2d83feec67e3a1f4
Cr-Commit-Position: refs/heads/master@{#34459}
==========

[commit-bot: I haz the power, 2016-03-03 10:18:57]

Patchset 2 (id:??) landed as
https://crrev.com/2689548e38c68bb6294fed5e2d83feec67e3a1f4
Cr-Commit-Position: refs/heads/master@{#34459}