MarkBit cleanup: They have to be accessed through Marking accessors.

MarkBit cleanup: They have to be accessed through Marking accessors. Avoid arbitrary abuse of mark bits and make marking explicit.

Added DCHECKs to mark bit transitions to check source state.

BUG=

Committed: https://crrev.com/ba70a7a3e189bc11da38c2cacf4900794ac53214
Cr-Commit-Position: refs/heads/master@{#27689}

[Hannes Payer (out of office), 2015-03-26 21:29:57]

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

[ulan, 2015-03-27 08:36:55]

Nice cleanup!

https://codereview.chromium.org/1040443002/diff/20001/src/heap/incremental-ma...
File src/heap/incremental-marking.cc (right):

https://codereview.chromium.org/1040443002/diff/20001/src/heap/incremental-ma...
src/heap/incremental-marking.cc:141: if (Marking::IsMarked(mark_bit)) return;
I like IsWhite(), IsBlack() predicates because they don't expose internal
marking patterns. IsMarked() however is at a lower level and assumes that the
reader knows about the bit shared between black and grey colors.

Maybe rename IsMarked to IsBlackOrGrey or IsNotWhite?

https://codereview.chromium.org/1040443002/diff/20001/src/heap/mark-compact.cc
File src/heap/mark-compact.cc (right):

https://codereview.chromium.org/1040443002/diff/20001/src/heap/mark-compact.c...
src/heap/mark-compact.cc:603: MarkBit end) {
This can clear bits outside [start, end] since we are not handling bits in the
cells of start and end specially.

[Hannes Payer (out of office), 2015-03-30 15:09:26]

https://codereview.chromium.org/1040443002/diff/20001/src/heap/incremental-ma...
File src/heap/incremental-marking.cc (right):

https://codereview.chromium.org/1040443002/diff/20001/src/heap/incremental-ma...
src/heap/incremental-marking.cc:141: if (Marking::IsMarked(mark_bit)) return;
On 2015/03/27 08:36:55, ulan wrote:
> I like IsWhite(), IsBlack() predicates because they don't expose internal
> marking patterns. IsMarked() however is at a lower level and assumes that the
> reader knows about the bit shared between black and grey colors.
> 
> Maybe rename IsMarked to IsBlackOrGrey or IsNotWhite?

Done.

https://codereview.chromium.org/1040443002/diff/20001/src/heap/mark-compact.cc
File src/heap/mark-compact.cc (right):

https://codereview.chromium.org/1040443002/diff/20001/src/heap/mark-compact.c...
src/heap/mark-compact.cc:603: MarkBit end) {
On 2015/03/27 08:36:55, ulan wrote:
> This can clear bits outside [start, end] since we are not handling bits in the
> cells of start and end specially.

I would have to expose the cell() call if we would like to pass in cells. I
would rather keep it as is or change it to just set the given bits to 0, similar
to SetAllMarkBitsInRange (ClearAllMarkBitsInRange). Note, these methods will be
deprecated soon.

[ulan, 2015-03-30 15:17:40]

lgtm

https://codereview.chromium.org/1040443002/diff/20001/src/heap/mark-compact.cc
File src/heap/mark-compact.cc (right):

https://codereview.chromium.org/1040443002/diff/20001/src/heap/mark-compact.c...
src/heap/mark-compact.cc:603: MarkBit end) {
On 2015/03/30 15:09:25, Hannes Payer wrote:
> On 2015/03/27 08:36:55, ulan wrote:
> > This can clear bits outside [start, end] since we are not handling bits in
the
> > cells of start and end specially.
> 
> I would have to expose the cell() call if we would like to pass in cells. I
> would rather keep it as is or change it to just set the given bits to 0,
similar
> to SetAllMarkBitsInRange (ClearAllMarkBitsInRange). Note, these methods will
be
> deprecated soon.

OK

[Hannes Payer (out of office), 2015-03-31 07:04:15]

The CQ bit was checked by hpayer@chromium.org

[commit-bot: I haz the power, 2015-03-31 07:04:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1040443002/40001

[commit-bot: I haz the power, 2015-03-31 07:08:03]

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

[commit-bot: I haz the power, 2015-03-31 07:08:03]

Try jobs failed on following builders:
  v8_linux64_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_rel/builds/4460)

[Hannes Payer (out of office), 2015-04-09 08:30:59]

The CQ bit was checked by hpayer@chromium.org

[Hannes Payer (out of office), 2015-04-09 08:31:00]

The patchset sent to the CQ was uploaded after l-g-t-m from ulan@chromium.org
Link to the patchset: https://codereview.chromium.org/1040443002/#ps60001
(title: " ")

[commit-bot: I haz the power, 2015-04-09 08:31:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1040443002/60001

[commit-bot: I haz the power, 2015-04-09 08:55:45]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-04-09 08:55:55]

Patchset 4 (id:??) landed as
https://crrev.com/ba70a7a3e189bc11da38c2cacf4900794ac53214
Cr-Commit-Position: refs/heads/master@{#27689}