Optimize Object.seal and Object.preventExtensions

Optimize Object.seal and Object.preventExtensions

They both now run fast (due to utilizing transitions instead of always
creating new maps) and sealed or non-extensible objects can stay in
fast mode after transitioning.

This almost entirely reuses the code for transitioning objects
frozen by Object.freeze(), with the added benefit of freeing
up a bit on the map (we no longer keep track of frozen-ness,
as that bit wasn't used for anything interesting).

BUG=v8:3662, chromium:115960
LOG=y

[adamk, 2014-12-04 02:15:10]

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

[adamk, 2014-12-04 20:57:12]

Now supports Object.preventExtensions, too.

[Igor Sheludko, 2014-12-05 15:14:34]

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

[adamk, 2014-12-09 21:50:49]

adamk@chromium.org changed reviewers:
- verwaest@chromium.org

[adamk, 2014-12-09 21:50:50]

Review ping? Igor, I get the impression this is right up your alley.

[Igor Sheludko, 2014-12-10 10:36:15]

It's really great that we now have one more free bit in the map!

lgtm with a nit:

https://codereview.chromium.org/776143005/diff/40001/src/objects.h
File src/objects.h (right):

https://codereview.chromium.org/776143005/diff/40001/src/objects.h#newcode5627
src/objects.h:5627: class Symbol;
I think src/globals.h is a better place for this.

[Igor Sheludko, 2014-12-10 11:31:15]

+ one nit:

https://codereview.chromium.org/776143005/diff/40001/src/objects-printer.cc
File src/objects-printer.cc (right):

https://codereview.chromium.org/776143005/diff/40001/src/objects-printer.cc#n...
src/objects-printer.cc:1139: if (key == GetHeap()->frozen_symbol()) {
Please add support for seal and nonextensible transitions here.

[adamk, 2014-12-10 18:46:01]

https://codereview.chromium.org/776143005/diff/40001/src/objects-printer.cc
File src/objects-printer.cc (right):

https://codereview.chromium.org/776143005/diff/40001/src/objects-printer.cc#n...
src/objects-printer.cc:1139: if (key == GetHeap()->frozen_symbol()) {
On 2014/12/10 11:31:15, Igor Sheludko wrote:
> Please add support for seal and nonextensible transitions here.

Done.

https://codereview.chromium.org/776143005/diff/40001/src/objects.h
File src/objects.h (right):

https://codereview.chromium.org/776143005/diff/40001/src/objects.h#newcode5627
src/objects.h:5627: class Symbol;
On 2014/12/10 10:36:14, Igor Sheludko wrote:
> I think src/globals.h is a better place for this.

Thanks for the pointer, I didn't know about that list of forward-decls. String
and Name are already there, added Symbol.

[adamk, 2014-12-10 18:46:07]

The CQ bit was checked by adamk@chromium.org

[commit-bot: I haz the power, 2014-12-10 18:46:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/776143005/60001

[commit-bot: I haz the power, 2014-12-10 19:08:16]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-12-10 19:08:17]

Try jobs failed on following builders:
  v8_linux_arm64_rel on tryserver.v8
(http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm64_rel/builds/1686)

[adamk, 2014-12-10 19:23:03]

The CQ bit was checked by adamk@chromium.org

[commit-bot: I haz the power, 2014-12-10 19:23:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/776143005/80001

[commit-bot: I haz the power, 2014-12-10 20:02:55]

Committed patchset #5 (id:80001)