[turbofan] Lower mapped arguments objects in inline frame.

[turbofan] Lower mapped arguments objects in inline frame.

This lowers JSCreateArguments nodes within inline (i.e. non-outermost)
frames that create "mapped arguments objects" to inline allocations.

The arguments count as well as each value is statically known and can be
directly stored into the arguments object. Note that the object is still
context-dependent and the map is loaded from the current context. The
object size is not taken into account for now, we might want to limit it
later though to keep code size bounded.

R=jarin@chromium.org

Committed: https://crrev.com/d1f773026ca326643e24994ca5a6c7fe73b71c40
Cr-Commit-Position: refs/heads/master@{#31619}

[Michael Starzinger, 2015-10-27 14:02:09]

Description was changed from

==========
[turbofan] Lower mapped arguments objects in inline frame.

This lowers JSCreateArguments nodes within inline (i.e. non-outermost)
frames that create "mapped arguments objects" to inline allocations.

The arguments count as well as each value is statically known and can be
directly stored into the arguments object. Note that the object is still
context-dependent and the map is loaded from the current context. The
object size is not taken into account for now, we might want to limit it
later though to keep code size bounded.

R=bmeurer@chromium.org
==========

to

==========
[turbofan] Lower mapped arguments objects in inline frame.

This lowers JSCreateArguments nodes within inline (i.e. non-outermost)
frames that create "mapped arguments objects" to inline allocations.

The arguments count as well as each value is statically known and can be
directly stored into the arguments object. Note that the object is still
context-dependent and the map is loaded from the current context. The
object size is not taken into account for now, we might want to limit it
later though to keep code size bounded.

R=jarin@chromium.org
==========

[Michael Starzinger, 2015-10-27 14:02:09]

mstarzinger@chromium.org changed reviewers:
+ jarin@chromium.org
- bmeurer@chromium.org

[Jarin, 2015-10-27 15:47:24]

lgtm.

https://codereview.chromium.org/1403363004/diff/40001/src/compiler/js-typed-l...
File src/compiler/js-typed-lowering.cc (right):

https://codereview.chromium.org/1403363004/diff/40001/src/compiler/js-typed-l...
src/compiler/js-typed-lowering.cc:1965: bool* has_aliased_arguments) {
Calling this a 'map' is a bit confusing (but I do not have a constructive
suggestion here).

[Michael Starzinger, 2015-10-27 17:22:03]

https://codereview.chromium.org/1403363004/diff/40001/src/compiler/js-typed-l...
File src/compiler/js-typed-lowering.cc (right):

https://codereview.chromium.org/1403363004/diff/40001/src/compiler/js-typed-l...
src/compiler/js-typed-lowering.cc:1965: bool* has_aliased_arguments) {
On 2015/10/27 15:47:24, Jarin wrote:
> Calling this a 'map' is a bit confusing (but I do not have a constructive
> suggestion here).

Acknowledged. The phrase "parameter map" is the canonical term we use for this
elements backing store in the runtime. See e.g. "class
SloppyArgumentsElementsAccessor" in elements.cc about that. I am happy to rename
it here, I just went with the name that is used everywhere else.

[Michael Starzinger, 2015-10-28 09:09:57]

https://codereview.chromium.org/1403363004/diff/40001/src/compiler/js-typed-l...
File src/compiler/js-typed-lowering.cc (right):

https://codereview.chromium.org/1403363004/diff/40001/src/compiler/js-typed-l...
src/compiler/js-typed-lowering.cc:1965: bool* has_aliased_arguments) {
On 2015/10/27 17:22:03, Michael Starzinger wrote:
> On 2015/10/27 15:47:24, Jarin wrote:
> > Calling this a 'map' is a bit confusing (but I do not have a constructive
> > suggestion here).
> 
> Acknowledged. The phrase "parameter map" is the canonical term we use for this
> elements backing store in the runtime. See e.g. "class
> SloppyArgumentsElementsAccessor" in elements.cc about that. I am happy to
rename
> it here, I just went with the name that is used everywhere else.

Done. Renamed to "AllocateAliasedArguments" as per offline discussion.

[Jarin, 2015-10-28 09:21:30]

still lgtm. Thanks!

[Michael Starzinger, 2015-10-28 09:29:20]

The CQ bit was checked by mstarzinger@chromium.org

[commit-bot: I haz the power, 2015-10-28 09:29:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1403363004/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1403363004/60001

[commit-bot: I haz the power, 2015-10-28 09:31:29]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-10-28 09:31:55]

Patchset 4 (id:??) landed as
https://crrev.com/d1f773026ca326643e24994ca5a6c7fe73b71c40
Cr-Commit-Position: refs/heads/master@{#31619}