Double the default heap size on 64-bit platforms to account for all pointers taking up twice the am…

Double the default heap size on 64-bit platforms to account for all pointers taking up twice the amount of memory.

R=iposva@google.com
BUG=

Committed: https://code.google.com/p/dart/source/detail?r=27466

[kasperl, 2013-09-12 10:46:41]

We're seeing a few cases where we are running out of memory in dart2js on 64-bit
platforms, but not on 32-bit. We're working on improving the working set of
dart2js, but maybe this would be a reasonable change for all users of Dart on
64-bit machines? 

What do you think?

[Ivan Posva, 2013-09-13 07:41:07]

Please keep the code size where it is. We will need to work out the correct
expansion factor on a per architecture basis.

LGTM as discussed.

-Ivan

https://codereview.chromium.org/24113004/diff/1/runtime/vm/heap.h
File runtime/vm/heap.h (right):

https://codereview.chromium.org/24113004/diff/1/runtime/vm/heap.h#newcode59
runtime/vm/heap.h:59: static const intptr_t kHeapSizeInMB = 512;
How about the code below to avoid the ifdefs?

static const intptr_t kHeapSizeInMWords = 128;
static const intptr_t kHeapSizeInMB = kHeapSizeInMWords * kWordSize;

[kasperl, 2013-09-13 07:46:22]

https://codereview.chromium.org/24113004/diff/1/runtime/vm/heap.h
File runtime/vm/heap.h (right):

https://codereview.chromium.org/24113004/diff/1/runtime/vm/heap.h#newcode59
runtime/vm/heap.h:59: static const intptr_t kHeapSizeInMB = 512;
On 2013/09/13 07:41:08, Ivan Posva wrote:
> How about the code below to avoid the ifdefs?
> 
> static const intptr_t kHeapSizeInMWords = 128;
> static const intptr_t kHeapSizeInMB = kHeapSizeInMWords * kWordSize;

Done.

[kasperl, 2013-09-13 07:52:19]

Committed patchset #2 manually as r27466 (presubmit successful).