Add debug mirror support for ES6 Map/Set iterators.

Add debug mirror support for ES6 Map/Set iterators.

This is to show values preview of an iterator in DevTools console.

API=v8::Value::IsMapIterator, v8::Value::IsSetIterator
BUG=chromium:427868
R=arv@chromium.org, yangguo@chromium.org, adamk@chromium.org
LOG=Y

Committed: https://code.google.com/p/v8/source/detail?r=25100

[arv (Not doing code reviews), 2014-10-31 10:20:18]

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

[arv (Not doing code reviews), 2014-10-31 10:20:19]

FYI

https://codereview.chromium.org/693813002/diff/20001/src/factory.cc
File src/factory.cc (right):

https://codereview.chromium.org/693813002/diff/20001/src/factory.cc#newcode1725
src/factory.cc:1725: Handle<JSMapIterator> Factory::NewJSMapIterator() {
Maybe this should take the table, index and kind since without those the
iterator is not going to behave reasonable.

https://codereview.chromium.org/693813002/diff/20001/test/mjsunit/es6/mirror-...
File test/mjsunit/es6/mirror-iterators.js (right):

https://codereview.chromium.org/693813002/diff/20001/test/mjsunit/es6/mirror-...
test/mjsunit/es6/mirror-iterators.js:38: testIteratorMirror(set.entries(), [[41,
41], [42, 42], [o1, o1], [o2, o2]]);
I think it would be good to have a test that  creates a mirror after the
original iterator is halfway through.

[aandrey, 2014-10-31 10:43:22]

https://codereview.chromium.org/693813002/diff/20001/src/factory.cc
File src/factory.cc (right):

https://codereview.chromium.org/693813002/diff/20001/src/factory.cc#newcode1725
src/factory.cc:1725: Handle<JSMapIterator> Factory::NewJSMapIterator() {
On 2014/10/31 10:20:18, arv wrote:
> Maybe this should take the table, index and kind since without those the
> iterator is not going to behave reasonable.

It's not easy given how the CALL_HEAP_FUNCTION macro is implemented.

https://codereview.chromium.org/693813002/diff/20001/test/mjsunit/es6/mirror-...
File test/mjsunit/es6/mirror-iterators.js (right):

https://codereview.chromium.org/693813002/diff/20001/test/mjsunit/es6/mirror-...
test/mjsunit/es6/mirror-iterators.js:38: testIteratorMirror(set.entries(), [[41,
41], [42, 42], [o1, o1], [o2, o2]]);
On 2014/10/31 10:20:18, arv wrote:
> I think it would be good to have a test that  creates a mirror after the
> original iterator is halfway through.

Done.

[aandrey, 2014-10-31 10:45:50]

FYI, DevTools side change: https://codereview.chromium.org/694753002/

[Yang, 2014-11-03 12:26:02]

The debugger part lgtm. I'll leave the review of the runtime part to Erik or
Adam.

[arv (Not doing code reviews), 2014-11-03 17:00:15]

LGTM

Maybe add a comment in factory?

[aandrey, 2014-11-04 10:01:31]

On 2014/11/03 17:00:15, arv wrote:
> LGTM
> 
> Maybe add a comment in factory?

Added a TODO. Let me investigate into it separately.

[aandrey, 2014-11-04 10:02:37]

Committed patchset #5 (id:80001) manually as 25100 (presubmit successful).