Only evaluate length once in %TypedArray%.prototype.set

Only evaluate length once in %TypedArray%.prototype.set

The ES6 spec for this function declares that ToLength
should only be called once. We were evaluating it multiple
times, so if length was an object with a valueOf method,
we could see effects take place multiple times.

R=littledan@chromium.org
LOG=N
BUG=v8:4218
Committed: https://crrev.com/df999c9790e96a72a6c56e67182a144b0e718591
Cr-Commit-Position: refs/heads/master@{#30240}

[Eric Caruso, 2015-07-13 23:29:30]

ejcaruso@chromium.org changed reviewers:
+ littledan@chromium.org
- littedan@chromium.org

[Dan Ehrenberg, 2015-07-13 23:47:30]

Looks good, just a minor suggestion.

https://codereview.chromium.org/1237583005/diff/1/test/mjsunit/es6/typedarray...
File test/mjsunit/es6/typedarray-set-length.js (right):

https://codereview.chromium.org/1237583005/diff/1/test/mjsunit/es6/typedarray...
test/mjsunit/es6/typedarray-set-length.js:27: a.set({length: {valueOf:
lengthValue}});
Just as a sanity check, test here that lengthCalled = true?

[adamk, 2015-07-14 00:14:19]

adamk@chromium.org changed reviewers:
+ adamk@chromium.org

[adamk, 2015-07-14 00:14:19]

Looking good. Can you also add some tests demonstrating that you're calling
$toLength (and not just valueOf)? E.g., returning various non-integers from
length (a float, NaN, string, etc)?

[Eric Caruso, 2015-08-19 00:40:43]

PTAL, thanks.

[Dan Ehrenberg, 2015-08-19 00:41:04]

lgtm

Wow, very well-tested.

[adamk, 2015-08-19 00:46:43]

lgtm!

[Eric Caruso, 2015-08-19 00:47:19]

The CQ bit was checked by ejcaruso@chromium.org

[commit-bot: I haz the power, 2015-08-19 00:47:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1237583005/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1237583005/40001

[commit-bot: I haz the power, 2015-08-19 01:33:03]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-08-19 01:33:18]

Patchset 3 (id:??) landed as
https://crrev.com/df999c9790e96a72a6c56e67182a144b0e718591
Cr-Commit-Position: refs/heads/master@{#30240}