Add flags for write barrier elimination and local allocation folding.

Add flags for write barrier elimination and local allocation folding.

R=hpayer@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=19382

[Hannes Payer (out of office), 2014-02-14 12:02:52]

LGTM, one nit

https://codereview.chromium.org/166163003/diff/1/src/flag-definitions.h
File src/flag-definitions.h (right):

https://codereview.chromium.org/166163003/diff/1/src/flag-definitions.h#newco...
src/flag-definitions.h:255: DEFINE_bool(use_write_barrier_elimination, true,
"eliminate write barriers")
We are still eliminating write barriers when this flag is turned off. We should
relate it to the allocate case.

[Michael Starzinger, 2014-02-14 14:37:34]

Comments addressed. Landing.

https://codereview.chromium.org/166163003/diff/1/src/flag-definitions.h
File src/flag-definitions.h (right):

https://codereview.chromium.org/166163003/diff/1/src/flag-definitions.h#newco...
src/flag-definitions.h:255: DEFINE_bool(use_write_barrier_elimination, true,
"eliminate write barriers")
On 2014/02/14 12:02:52, Hannes Payer wrote:
> We are still eliminating write barriers when this flag is turned off. We
should
> relate it to the allocate case.

Done. I adapted the description accordingly and made if more expressive.
Couldn't come up with a better name for the flag itself though.

[Michael Starzinger, 2014-02-14 14:58:12]

Committed patchset #2 manually as r19382 (presubmit successful).