[heap] Old-to-new pointer updates need atomic accessors.

[heap] Old-to-new pointer updates need atomic accessors.

This CL also introduces a NoBarrierAtomicValue with NoBarrier accessors.

BUG=chromium:648568
Committed: https://crrev.com/10ffd2b111aff1e3a85a7eb61119c177086c15a0
Cr-Commit-Position: refs/heads/master@{#40213}

[Hannes Payer (out of office), 2016-10-12 07:57:18]

The CQ bit was checked by hpayer@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-10-12 07:57:24]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Hannes Payer (out of office), 2016-10-12 07:57:54]

Description was changed from

==========
[heap] Old-to-new pointer updates need atomic accessors.

BUG=chromium:648568
==========

to

==========
[heap] Old-to-new pointer updates need atomic accessors.

This CL also introduces a NonAtomicValue with NoBarrier accessors.

BUG=chromium:648568
==========

[Hannes Payer (out of office), 2016-10-12 07:57:54]

hpayer@chromium.org changed reviewers:
+ mlippautz@chromium.org, ulan@chromium.org

[Michael Lippautz, 2016-10-12 08:04:16]

Please add a simple unit test to 
  atomic-utils-unittest.cc
that checks that single-threaded initialization, SetValue, and Value work.

(Sounds trivial, but I discovered an error in one of the util classes this
way...)

https://codereview.chromium.org/2408233004/diff/1/src/base/atomic-utils.h
File src/base/atomic-utils.h (right):

https://codereview.chromium.org/2408233004/diff/1/src/base/atomic-utils.h#new...
src/base/atomic-utils.h:57: class NonAtomicValue {
You sure about this name?

I'd rather call it NoBarrierAtomicValue or something similar. NonAtomicValue
doesn't suggest the use of atomics.

https://codereview.chromium.org/2408233004/diff/1/src/heap/mark-compact.cc
File src/heap/mark-compact.cc (right):

https://codereview.chromium.org/2408233004/diff/1/src/heap/mark-compact.cc#ne...
src/heap/mark-compact.cc:3635: base::NonAtomicValue<Object*>* slot =
Can we hide this cast in a constructor of the value, e.g.
NoBarrierAtomicValue::fromAddress(...)

[ulan, 2016-10-12 08:32:39]

https://codereview.chromium.org/2408233004/diff/1/src/base/atomic-utils.h
File src/base/atomic-utils.h (right):

https://codereview.chromium.org/2408233004/diff/1/src/base/atomic-utils.h#new...
src/base/atomic-utils.h:57: class NonAtomicValue {
On 2016/10/12 08:04:15, Michael Lippautz wrote:
> You sure about this name?
> 
> I'd rather call it NoBarrierAtomicValue or something similar. NonAtomicValue
> doesn't suggest the use of atomics.

+1 to NoBarrierAtomicValue

[commit-bot: I haz the power, 2016-10-12 08:55:33]

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

[commit-bot: I haz the power, 2016-10-12 08:55:34]

Dry run: This issue passed the CQ dry run.

[Hannes Payer (out of office), 2016-10-12 11:27:45]

https://codereview.chromium.org/2408233004/diff/1/src/base/atomic-utils.h
File src/base/atomic-utils.h (right):

https://codereview.chromium.org/2408233004/diff/1/src/base/atomic-utils.h#new...
src/base/atomic-utils.h:57: class NonAtomicValue {
On 2016/10/12 08:32:39, ulan wrote:
> On 2016/10/12 08:04:15, Michael Lippautz wrote:
> > You sure about this name?
> > 
> > I'd rather call it NoBarrierAtomicValue or something similar. NonAtomicValue
> > doesn't suggest the use of atomics.
> 
> +1 to NoBarrierAtomicValue

Changed the name. Note that the no barrier accessors are indeed non-atomic
accessors.

https://codereview.chromium.org/2408233004/diff/1/src/heap/mark-compact.cc
File src/heap/mark-compact.cc (right):

https://codereview.chromium.org/2408233004/diff/1/src/heap/mark-compact.cc#ne...
src/heap/mark-compact.cc:3635: base::NonAtomicValue<Object*>* slot =
On 2016/10/12 08:04:15, Michael Lippautz wrote:
> Can we hide this cast in a constructor of the value, e.g.
> NoBarrierAtomicValue::fromAddress(...)

Done.

[Michael Lippautz, 2016-10-12 11:36:17]

lgtm

https://codereview.chromium.org/2408233004/diff/20001/src/heap/mark-compact.cc
File src/heap/mark-compact.cc (right):

https://codereview.chromium.org/2408233004/diff/20001/src/heap/mark-compact.c...
src/heap/mark-compact.cc:3652: slot_reference = slot->Value();
nit: You can manually inline this slot->Value() call into the following call if
you like.

[Hannes Payer (out of office), 2016-10-12 11:38:23]

https://codereview.chromium.org/2408233004/diff/20001/src/heap/mark-compact.cc
File src/heap/mark-compact.cc (right):

https://codereview.chromium.org/2408233004/diff/20001/src/heap/mark-compact.c...
src/heap/mark-compact.cc:3652: slot_reference = slot->Value();
On 2016/10/12 11:36:17, Michael Lippautz wrote:
> nit: You can manually inline this slot->Value() call into the following call
if
> you like.

Done.

[Hannes Payer (out of office), 2016-10-12 11:38:27]

The CQ bit was checked by hpayer@chromium.org

[Hannes Payer (out of office), 2016-10-12 11:38:27]

The patchset sent to the CQ was uploaded after l-g-t-m from
mlippautz@chromium.org
Link to the patchset: https://codereview.chromium.org/2408233004/#ps40001
(title: "inline check")

[commit-bot: I haz the power, 2016-10-12 11:38:37]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Hannes Payer (out of office), 2016-10-12 11:56:58]

Description was changed from

==========
[heap] Old-to-new pointer updates need atomic accessors.

This CL also introduces a NonAtomicValue with NoBarrier accessors.

BUG=chromium:648568
==========

to

==========
[heap] Old-to-new pointer updates need atomic accessors.

This CL also introduces a NoBarrierAtomicValue with NoBarrier accessors.

BUG=chromium:648568
==========

[commit-bot: I haz the power, 2016-10-12 12:04:56]

Description was changed from

==========
[heap] Old-to-new pointer updates need atomic accessors.

This CL also introduces a NoBarrierAtomicValue with NoBarrier accessors.

BUG=chromium:648568
==========

to

==========
[heap] Old-to-new pointer updates need atomic accessors.

This CL also introduces a NoBarrierAtomicValue with NoBarrier accessors.

BUG=chromium:648568
==========

[commit-bot: I haz the power, 2016-10-12 12:04:57]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-10-12 12:05:08]

Description was changed from

==========
[heap] Old-to-new pointer updates need atomic accessors.

This CL also introduces a NoBarrierAtomicValue with NoBarrier accessors.

BUG=chromium:648568
==========

to

==========
[heap] Old-to-new pointer updates need atomic accessors.

This CL also introduces a NoBarrierAtomicValue with NoBarrier accessors.

BUG=chromium:648568

Committed: https://crrev.com/10ffd2b111aff1e3a85a7eb61119c177086c15a0
Cr-Commit-Position: refs/heads/master@{#40213}
==========

[commit-bot: I haz the power, 2016-10-12 12:05:09]

Patchset 3 (id:??) landed as
https://crrev.com/10ffd2b111aff1e3a85a7eb61119c177086c15a0
Cr-Commit-Position: refs/heads/master@{#40213}