dart2js cps: Add CharCodeAt builtin.

dart2js cps: Add CharCodeAt builtin.

1. String.codeUnitAt is lowered to a bounds check and a CharCodeAt.
2. Constant-fold String.codeUnitAt.

R=asgerf@google.com

Committed: https://github.com/dart-lang/sdk/commit/9b580e5e1086243d291bf8c097bfe878e947b994

Reverted: https://github.com/dart-lang/sdk/commit/6db18cbbd8a68abe1b42715110943cc4f2c65190

Investigating:
tools/test.py -mrelease -cdart2js -rd8 --cps-ir language/invocation_mirror_invoke_on2_test

Committed: https://github.com/dart-lang/sdk/commit/17c9c97705c4d73dfb9fa0a9c42afed1df204cb6

[sra1, 2015-11-14 00:02:32]

Patchset #1 (id:1) has been deleted

[sra1, 2015-11-18 23:40:47]

sra@google.com changed reviewers:
+ asgerf@google.com

[asgerf, 2015-11-19 08:50:05]

lgtm

[sra1, 2015-11-23 20:39:32]

https://codereview.chromium.org/1437373002/diff/80001/pkg/compiler/lib/src/cp...
File pkg/compiler/lib/src/cps_ir/builtin_operator.dart (right):

https://codereview.chromium.org/1437373002/diff/80001/pkg/compiler/lib/src/cp...
pkg/compiler/lib/src/cps_ir/builtin_operator.dart:75: CharCodeAt,
Question: will GVN hoist this above the bounds check?
There is no edge from the bounds check to the bounds use to prevent that.

[asgerf, 2015-11-24 11:28:31]

https://codereview.chromium.org/1437373002/diff/80001/pkg/compiler/lib/src/cp...
File pkg/compiler/lib/src/cps_ir/builtin_operator.dart (right):

https://codereview.chromium.org/1437373002/diff/80001/pkg/compiler/lib/src/cp...
pkg/compiler/lib/src/cps_ir/builtin_operator.dart:75: CharCodeAt,
On 2015/11/23 20:39:32, sra1 wrote:
> Question: will GVN hoist this above the bounds check?
> There is no edge from the bounds check to the bounds use to prevent that.

Yes, nice catch. We should disable lifting for these. We could just make it a
BuiltinMethod until we land a better infrastructure to keep track of these
things.

We might want to add "witness" nodes like in the SSA (essentially non-unary
refinements), but unless BCE is going to hoist witness nodes and follow up with
another LICM pass, I think the effect will be same as just disabling lifting for
the nodes that need such witnesses.

[sra1, 2015-11-25 23:20:46]

Description was changed from

==========
dart2js cps: Add CharCodeAt builtin.

1. String.codeUnitAt is lowered to a bounds check and a CharCodeAt.
2. Constant-fold String.codeUnitAt.
==========

to

==========
dart2js cps: Add CharCodeAt builtin.

1. String.codeUnitAt is lowered to a bounds check and a CharCodeAt.
2. Constant-fold String.codeUnitAt.

R=asgerf@google.com

Committed:
https://github.com/dart-lang/sdk/commit/9b580e5e1086243d291bf8c097bfe878e947b994
==========

[sra1, 2015-11-25 23:20:47]

Committed patchset #4 (id:80001) manually as
9b580e5e1086243d291bf8c097bfe878e947b994 (presubmit successful).

[sra1, 2015-11-26 01:48:57]

Description was changed from

==========
dart2js cps: Add CharCodeAt builtin.

1. String.codeUnitAt is lowered to a bounds check and a CharCodeAt.
2. Constant-fold String.codeUnitAt.

R=asgerf@google.com

Committed:
https://github.com/dart-lang/sdk/commit/9b580e5e1086243d291bf8c097bfe878e947b994
==========

to

==========
dart2js cps: Add CharCodeAt builtin.

1. String.codeUnitAt is lowered to a bounds check and a CharCodeAt.
2. Constant-fold String.codeUnitAt.

R=asgerf@google.com

Committed:
https://github.com/dart-lang/sdk/commit/9b580e5e1086243d291bf8c097bfe878e947b994

Reverted:
https://github.com/dart-lang/sdk/commit/6db18cbbd8a68abe1b42715110943cc4f2c65190

Investigating:
tools/test.py -mrelease -cdart2js -rd8 --cps-ir
language/invocation_mirror_invoke_on2_test
==========

[sra1, 2015-11-27 21:40:24]

Description was changed from

==========
dart2js cps: Add CharCodeAt builtin.

1. String.codeUnitAt is lowered to a bounds check and a CharCodeAt.
2. Constant-fold String.codeUnitAt.

R=asgerf@google.com

Committed:
https://github.com/dart-lang/sdk/commit/9b580e5e1086243d291bf8c097bfe878e947b994

Reverted:
https://github.com/dart-lang/sdk/commit/6db18cbbd8a68abe1b42715110943cc4f2c65190

Investigating:
tools/test.py -mrelease -cdart2js -rd8 --cps-ir
language/invocation_mirror_invoke_on2_test
==========

to

==========
dart2js cps: Add CharCodeAt builtin.

1. String.codeUnitAt is lowered to a bounds check and a CharCodeAt.
2. Constant-fold String.codeUnitAt.

R=asgerf@google.com

Committed:
https://github.com/dart-lang/sdk/commit/9b580e5e1086243d291bf8c097bfe878e947b994

Reverted:
https://github.com/dart-lang/sdk/commit/6db18cbbd8a68abe1b42715110943cc4f2c65190

Investigating:
tools/test.py -mrelease -cdart2js -rd8 --cps-ir
language/invocation_mirror_invoke_on2_test

Committed:
https://github.com/dart-lang/sdk/commit/17c9c97705c4d73dfb9fa0a9c42afed1df204cb6
==========

[sra1, 2015-11-27 21:40:25]

Committed patchset #7 (id:140001) manually as
17c9c97705c4d73dfb9fa0a9c42afed1df204cb6 (presubmit successful).