Add a flag to over approximate the weak closure during GC

Add a flag to over approximate the weak closure during GC

BUG=v8:3862
R=hpayer@chromium.org
LOG=n

Committed: https://crrev.com/4357bef53bb5f1e151120c1680e15bcb93d7fd24
Cr-Commit-Position: refs/heads/master@{#26532}

[Hannes Payer (out of office), 2015-02-03 17:40:11]

LGTM, just nits.

https://codereview.chromium.org/894703002/diff/1/src/heap/heap.h
File src/heap/heap.h (right):

https://codereview.chromium.org/894703002/diff/1/src/heap/heap.h#newcode760
src/heap/heap.h:760: void OverApproximateWeakClosure(const char* gc_reason);
Please add a comment here how the over approximation works.

https://codereview.chromium.org/894703002/diff/1/src/heap/incremental-marking.cc
File src/heap/incremental-marking.cc (right):

https://codereview.chromium.org/894703002/diff/1/src/heap/incremental-marking...
src/heap/incremental-marking.cc:499: weak_closure_was_overapproximated_ = false;
Can we do that in the gc epilogue?

https://codereview.chromium.org/894703002/diff/1/src/heap/incremental-marking...
src/heap/incremental-marking.cc:785: if (FLAG_trace_incremental_marking) {
Can we add a separate method for that and dispatch between over approximate and
dispatch at the call site?

[jochen (gone - plz use gerrit), 2015-02-09 16:03:44]

https://codereview.chromium.org/894703002/diff/1/src/heap/heap.h
File src/heap/heap.h (right):

https://codereview.chromium.org/894703002/diff/1/src/heap/heap.h#newcode760
src/heap/heap.h:760: void OverApproximateWeakClosure(const char* gc_reason);
On 2015/02/03 at 17:40:11, Hannes Payer wrote:
> Please add a comment here how the over approximation works.

done

https://codereview.chromium.org/894703002/diff/1/src/heap/incremental-marking.cc
File src/heap/incremental-marking.cc (right):

https://codereview.chromium.org/894703002/diff/1/src/heap/incremental-marking...
src/heap/incremental-marking.cc:499: weak_closure_was_overapproximated_ = false;
On 2015/02/03 at 17:40:11, Hannes Payer wrote:
> Can we do that in the gc epilogue?

Done

https://codereview.chromium.org/894703002/diff/1/src/heap/incremental-marking...
src/heap/incremental-marking.cc:785: if (FLAG_trace_incremental_marking) {
On 2015/02/03 at 17:40:11, Hannes Payer wrote:
> Can we add a separate method for that and dispatch between over approximate
and dispatch at the call site?

done

https://codereview.chromium.org/894703002/diff/1/src/heap/incremental-marking...
src/heap/incremental-marking.cc:785: if (FLAG_trace_incremental_marking) {
On 2015/02/03 at 17:40:11, Hannes Payer wrote:
> Can we add a separate method for that and dispatch between over approximate
and dispatch at the call site?

done

[jochen (gone - plz use gerrit), 2015-02-09 16:03:50]

The CQ bit was checked by jochen@chromium.org

[commit-bot: I haz the power, 2015-02-09 16:04:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/894703002/20001

[commit-bot: I haz the power, 2015-02-09 16:25:55]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-02-09 16:26:11]

Patchset 2 (id:??) landed as
https://crrev.com/4357bef53bb5f1e151120c1680e15bcb93d7fd24
Cr-Commit-Position: refs/heads/master@{#26532}