Add flags to force or prevent setting of isolate.is_memory_constrained.

Add flags to force or prevent setting of isolate.is_memory_constrained.

Also enable MAYBE_BOOL flags for when you want to only do something if the flag was explicitly set to true or false.

BUG=None
R=hpayer@chromium.org, svenpanne@chromium.org

Committed: http://code.google.com/p/v8/source/detail?r=16733

[rmcilroy, 2013-09-13 11:47:12]

As requested.  This enables both forcing and preventing of the
memory_constrained flag.  PTAL.

[Hannes Payer (out of office), 2013-09-13 12:04:58]

LGTM

[Sven Panne, 2013-09-13 12:34:52]

Three-valued logic via 2 boolean + exclusion of one of the 4 possible combined
values => not exactly a candidate for the next coding beauty contest... ;-)

[rmcilroy, 2013-09-13 15:50:30]

On 2013/09/13 12:34:52, Sven Panne wrote:
> Three-valued logic via 2 boolean + exclusion of one of the 4 possible combined
> values => not exactly a candidate for the next coding beauty contest... ;-)

How about this instead - enabled the use of Maybe<bool> flag types.

Also fixed an issue with the isolate not actually being set up correctly due to
the default isolate being created before the flags were evaluated...

[Sven Panne, 2013-09-16 07:50:44]

LGTM. Our 2-step Isolate initialization + the code executed before main() is
nice, isn't it? :-]

https://codereview.chromium.org/23890027/diff/6001/src/flags.cc
File src/flags.cc (right):

https://codereview.chromium.org/23890027/diff/6001/src/flags.cc#newcode421
src/flags.cc:421: PrintF("Setting %d\n", !is_bool);
Remove the PrintF

[rmcilroy, 2013-09-16 08:19:49]

Thanks.  Could you land this for me please?

https://codereview.chromium.org/23890027/diff/6001/src/flags.cc
File src/flags.cc (right):

https://codereview.chromium.org/23890027/diff/6001/src/flags.cc#newcode421
src/flags.cc:421: PrintF("Setting %d\n", !is_bool);
On 2013/09/16 07:50:45, Sven Panne wrote:
> Remove the PrintF

Opps, thanks. Done.

[Sven Panne, 2013-09-16 09:52:54]

Hmmm, we have test failures in cctest/test-flags, see e.g.

   make -j32 ia32.debug.check TESTJOBS="cctest/test-flags"

So we need one more review round. *Nothing* in v8 is easy... :-}

[rmcilroy, 2013-09-16 12:17:34]

On 2013/09/16 09:52:54, Sven Panne wrote:
> Hmmm, we have test failures in cctest/test-flags, see e.g.
> 
>    make -j32 ia32.debug.check TESTJOBS="cctest/test-flags"
> 
> So we need one more review round. *Nothing* in v8 is easy... :-}

Whoops, I thought I'd run debug.check...  Fixed and added some additional tests
to test-flags.cc for maybe-bool args.

[Sven Panne, 2013-09-16 13:03:04]

Committed patchset #4 manually as r16733 (presubmit successful).