[es6] Refactor FormalParameter

[es6] Refactor FormalParameter

Store arity in FormalParameters; store name (instead of var) and is_rest flag in individual parameters. Ensure that the arity is always maintained consistently.

This is preparation for more parameter destructuring adjustments. In particular, a follow-up CL will separate parameter recording from declaring the variables.

R=adamk@chromium.org, littledan@chromium.org
BUG=v8:811
LOG=N

Committed: https://crrev.com/56bd11a11a4fc4b26f215ea5ca3217958db091fd
Cr-Commit-Position: refs/heads/master@{#30002}

[adamk, 2015-08-03 18:20:23]

This change lgtm, but as noted below it looks a little brittle. Is there no way
to better-encapsulate the incrementing logic in the PreParserFormalParameter
base class?

https://codereview.chromium.org/1259013003/diff/1/src/parser.h
File src/parser.h (right):

https://codereview.chromium.org/1259013003/diff/1/src/parser.h#newcode559
src/parser.h:559: DCHECK(arity == params.length());
DCHECK_EQ.

Also, it will probably be more clear after the followup, but it seems sad that
the only way to check this consistency is a DCHECK. Especially since the
incrementing code is now duplicated between preparser and parser.

https://codereview.chromium.org/1259013003/diff/1/src/preparser.h
File src/preparser.h (right):

https://codereview.chromium.org/1259013003/diff/1/src/preparser.h#newcode3673
src/preparser.h:3673: DCHECK(parameters->arity == 0);
DCHECK_EQ

[rossberg, 2015-08-04 13:44:22]

https://codereview.chromium.org/1259013003/diff/1/src/parser.h
File src/parser.h (right):

https://codereview.chromium.org/1259013003/diff/1/src/parser.h#newcode559
src/parser.h:559: DCHECK(arity == params.length());
On 2015/08/03 18:20:23, adamk wrote:
> DCHECK_EQ.

Done.

> Also, it will probably be more clear after the followup, but it seems sad that
> the only way to check this consistency is a DCHECK. Especially since the
> incrementing code is now duplicated between preparser and parser.

My thinking was that the parser/preparser duplication should go away eventually,
once statement parsing is unified. But the FormalParameter will stay separate.
So you want to move as little of the logic there as possible.

But maybe you are right, I'll reconsider in the follow-up CL.

https://codereview.chromium.org/1259013003/diff/1/src/preparser.h
File src/preparser.h (right):

https://codereview.chromium.org/1259013003/diff/1/src/preparser.h#newcode3673
src/preparser.h:3673: DCHECK(parameters->arity == 0);
On 2015/08/03 18:20:23, adamk wrote:
> DCHECK_EQ

Done.

[rossberg, 2015-08-04 13:44:30]

The CQ bit was checked by rossberg@chromium.org

[rossberg, 2015-08-04 13:44:30]

The patchset sent to the CQ was uploaded after l-g-t-m from adamk@chromium.org
Link to the patchset: https://codereview.chromium.org/1259013003/#ps40001
(title: "Comments")

[commit-bot: I haz the power, 2015-08-04 13:44:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1259013003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1259013003/40001

[commit-bot: I haz the power, 2015-08-04 14:24:44]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-08-04 14:25:22]

Patchset 3 (id:??) landed as
https://crrev.com/56bd11a11a4fc4b26f215ea5ca3217958db091fd
Cr-Commit-Position: refs/heads/master@{#30002}