Become: Also forward identity hashes.

Become: Also forward identity hashes.

Fixes #27107

R=johnmccutchan@google.com

Committed: https://github.com/dart-lang/sdk/commit/078ea2e4f107ffeb8da63245c48ccd43bcfb4f28

[rmacnak, 2016-08-18 19:59:19]

rmacnak@google.com changed reviewers:
+ johnmccutchan@google.com

[Cutch, 2016-08-18 20:55:38]

LGTM!

[rmacnak, 2016-08-18 21:10:51]

Description was changed from

==========
Become: Also forward identity hashes.

Fixes #27107
==========

to

==========
Become: Also forward identity hashes.

Fixes #27107

R=johnmccutchan@google.com

Committed:
https://github.com/dart-lang/sdk/commit/078ea2e4f107ffeb8da63245c48ccd43bcfb4f28
==========

[rmacnak, 2016-08-18 21:10:53]

Committed patchset #3 (id:40001) manually as
078ea2e4f107ffeb8da63245c48ccd43bcfb4f28 (presubmit successful).

[siva, 2016-08-19 00:08:14]

asiva@google.com changed reviewers:
+ asiva@google.com

[siva, 2016-08-19 00:08:15]

https://codereview.chromium.org/2259013002/diff/40001/runtime/vm/become.cc
File runtime/vm/become.cc (right):

https://codereview.chromium.org/2259013002/diff/40001/runtime/vm/become.cc#ne...
runtime/vm/become.cc:270: }
How does this work for internal VM objects, for example if before_obj and after
_obj are strings then it is not correct to get the hash of before_obj and set it
to the hash of after_obj?

[rmacnak, 2016-08-19 00:16:54]

https://codereview.chromium.org/2259013002/diff/40001/runtime/vm/become.cc
File runtime/vm/become.cc (right):

https://codereview.chromium.org/2259013002/diff/40001/runtime/vm/become.cc#ne...
runtime/vm/become.cc:270: }
On 2016/08/19 00:08:15, siva wrote:
> How does this work for internal VM objects, for example if before_obj and
after
> _obj are strings then it is not correct to get the hash of before_obj and set
it
> to the hash of after_obj?

A String's usual hash is the one inline in the object. This forwards identity
hashes in the weak tables.