Move Maps' back pointers from "transitions" to "constructor" field

Move Maps' back pointers from "transitions" to "constructor" field

Committed: https://crrev.com/affcfaf42801414d25b3e57271a9803a026f40ed
Cr-Commit-Position: refs/heads/master@{#26835}

[Jakob Kummerow, 2015-02-24 10:50:56]

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

[Jakob Kummerow, 2015-02-24 10:50:57]

PTAL.

This doesn't yet clean up the now-unused slot in the TransitionArray -- the next
CL will do that.

[Toon Verwaest, 2015-02-24 12:24:55]

lgtm with comment

https://codereview.chromium.org/950283002/diff/1/src/objects-inl.h
File src/objects-inl.h (right):

https://codereview.chromium.org/950283002/diff/1/src/objects-inl.h#newcode5497
src/objects-inl.h:5497: (value->IsMap() && GetBackPointer()->IsUndefined()));
DCHECK(!value->IsMap() || Map::cast(value)->GetConstructor() ==
constructor_or_backpointer())

https://codereview.chromium.org/950283002/diff/1/src/objects.cc
File src/objects.cc (right):

https://codereview.chromium.org/950283002/diff/1/src/objects.cc#newcode9558
src/objects.cc:9558: int hash =
ObjectAddressForHashing(constructor_or_backpointer()) >> 2;
GetConstructor, otherwise you won't find matching maps for maps in different
parts of the transition tree.

[Jakob Kummerow, 2015-02-24 16:30:26]

Thanks for the review, I've addressed your comments.

I've also fixed the combination of non-instance prototypes and map transitions,
and made sure that tests cover that scenario.

https://codereview.chromium.org/950283002/diff/1/src/objects-inl.h
File src/objects-inl.h (right):

https://codereview.chromium.org/950283002/diff/1/src/objects-inl.h#newcode5497
src/objects-inl.h:5497: (value->IsMap() && GetBackPointer()->IsUndefined()));
On 2015/02/24 12:24:55, Toon Verwaest wrote:
> DCHECK(!value->IsMap() || Map::cast(value)->GetConstructor() ==
> constructor_or_backpointer())

Done.

https://codereview.chromium.org/950283002/diff/1/src/objects.cc
File src/objects.cc (right):

https://codereview.chromium.org/950283002/diff/1/src/objects.cc#newcode9558
src/objects.cc:9558: int hash =
ObjectAddressForHashing(constructor_or_backpointer()) >> 2;
On 2015/02/24 12:24:55, Toon Verwaest wrote:
> GetConstructor, otherwise you won't find matching maps for maps in different
> parts of the transition tree.

Done.

[Jakob Kummerow, 2015-02-24 16:33:00]

The CQ bit was checked by jkummerow@chromium.org

[Jakob Kummerow, 2015-02-24 16:33:00]

The patchset sent to the CQ was uploaded after l-g-t-m from
verwaest@chromium.org
Link to the patchset: https://codereview.chromium.org/950283002/#ps40001 (title:
"rebased")

[commit-bot: I haz the power, 2015-02-24 16:34:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/950283002/40001

[commit-bot: I haz the power, 2015-02-24 16:44:33]

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

[commit-bot: I haz the power, 2015-02-24 16:44:34]

Try jobs failed on following builders:
  v8_linux_nodcheck_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_nodcheck_rel/build...)

[Jakob Kummerow, 2015-02-24 17:18:02]

The CQ bit was checked by jkummerow@chromium.org

[Jakob Kummerow, 2015-02-24 17:18:03]

The patchset sent to the CQ was uploaded after l-g-t-m from
verwaest@chromium.org
Link to the patchset: https://codereview.chromium.org/950283002/#ps60001 (title:
"add missing smi check")

[commit-bot: I haz the power, 2015-02-24 17:18:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/950283002/60001

[commit-bot: I haz the power, 2015-02-24 17:48:23]

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

[commit-bot: I haz the power, 2015-02-24 17:48:24]

Try jobs failed on following builders:
  v8_linux_arm64_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm64_rel/builds/3169)

[Jakob Kummerow, 2015-02-24 20:22:37]

The CQ bit was checked by jkummerow@chromium.org

[Jakob Kummerow, 2015-02-24 20:22:38]

The patchset sent to the CQ was uploaded after l-g-t-m from
verwaest@chromium.org
Link to the patchset: https://codereview.chromium.org/950283002/#ps80001 (title:
"fix stupidity on arm64")

[commit-bot: I haz the power, 2015-02-24 20:23:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/950283002/80001

[commit-bot: I haz the power, 2015-02-24 20:50:16]

Committed patchset #5 (id:80001)

[commit-bot: I haz the power, 2015-02-24 20:50:35]

Patchset 5 (id:??) landed as
https://crrev.com/affcfaf42801414d25b3e57271a9803a026f40ed
Cr-Commit-Position: refs/heads/master@{#26835}