Implement generator mirror

Implement generator mirror

R=yangguo@chromium.org, aandrey@chromium.org

BUG=v8:3292
LOG=N

Committed: https://code.google.com/p/v8/source/detail?r=24043

[wingo, 2014-09-17 12:25:42]

PTAL; I guess I have to hook up some serializer things too?

[aandrey, 2014-09-17 13:21:30]

https://codereview.chromium.org/580823002/diff/1/src/mirror-debugger.js
File src/mirror-debugger.js (right):

https://codereview.chromium.org/580823002/diff/1/src/mirror-debugger.js#newco...
src/mirror-debugger.js:1381: if (continuation < 0) return "running";
is it possible to test this status?

https://codereview.chromium.org/580823002/diff/1/src/mirror-debugger.js#newco...
src/mirror-debugger.js:1411: GeneratorMirror.prototype.context = function() {
Is this the same as this.func().script().context() ?

https://codereview.chromium.org/580823002/diff/1/test/mjsunit/es6/generator-m...
File test/mjsunit/es6/generator-mirror.js (right):

https://codereview.chromium.org/580823002/diff/1/test/mjsunit/es6/generator-m...
test/mjsunit/es6/generator-mirror.js:48: assertEquals(mirror.func().value(),
generator);
will mirror.func().scope() return valid scopes for a suspended generator?

[wingo, 2014-09-17 13:54:30]

Updated patch and comments below.

https://codereview.chromium.org/580823002/diff/1/src/mirror-debugger.js
File src/mirror-debugger.js (right):

https://codereview.chromium.org/580823002/diff/1/src/mirror-debugger.js#newco...
src/mirror-debugger.js:1381: if (continuation < 0) return "running";
On 2014/09/17 13:21:29, aandrey wrote:
> is it possible to test this status?

Done.

https://codereview.chromium.org/580823002/diff/1/src/mirror-debugger.js#newco...
src/mirror-debugger.js:1411: GeneratorMirror.prototype.context = function() {
On 2014/09/17 13:21:30, aandrey wrote:
> Is this the same as this.func().script().context() ?

Hum, I realized that it isn't -- it's one of the other 30 things in V8 that are
named "context" :/

This thing is the scope chain.  In generator functions, all locals are reified
on the scope chain ("context-allocated").  You can get the set of local
variables from a generator activation by looking at the set of properties of a
node on the scope chain, stopping when you find a node that is on the scope
chain of the function itself.  However I revised the patch not to expose this
any more, as I don't know the right way to expose a scope chain.

https://codereview.chromium.org/580823002/diff/1/test/mjsunit/es6/generator-m...
File test/mjsunit/es6/generator-mirror.js (right):

https://codereview.chromium.org/580823002/diff/1/test/mjsunit/es6/generator-m...
test/mjsunit/es6/generator-mirror.js:48: assertEquals(mirror.func().value(),
generator);
On 2014/09/17 13:21:30, aandrey wrote:
> will mirror.func().scope() return valid scopes for a suspended generator?

Yes, because func().scope() is the scope captured by a function, not the scope
of the suspended activation.

[aandrey, 2014-09-18 08:45:21]

looking good, deferring to Yang

https://codereview.chromium.org/580823002/diff/20001/test/mjsunit/es6/generat...
File test/mjsunit/es6/generator-mirror.js (right):

https://codereview.chromium.org/580823002/diff/20001/test/mjsunit/es6/generat...
test/mjsunit/es6/generator-mirror.js:54:
assertEquals(debug.MakeMirror(iter).status(), 'running');
nit: expected value is the first argument, actual value - second
nit: use "" or '' consistently

[wingo, 2014-09-18 09:18:19]

Updated patch to fix nits, and renamed test to be generators-mirror instead of
generator-mirror, in harmony with other similar files.

[Yang, 2014-09-18 09:55:16]

On 2014/09/18 09:18:19, wingo wrote:
> Updated patch to fix nits, and renamed test to be generators-mirror instead of
> generator-mirror, in harmony with other similar files.

lgtm.

[wingo, 2014-09-18 13:30:25]

Committed patchset #3 manually as 24043 (presubmit successful).