Guard against frames across pages, in the profiler.

Guard against frames across pages, in the profiler.

On Windows, if a page is not touched yet by the stack's thread, the page may be a guard page.

BUG=
R=johnmccutchan@google.com

Committed: https://code.google.com/p/dart/source/detail?r=36623

[Cutch, 2014-05-23 11:44:29]

lgtm with #ifdef fix

https://codereview.chromium.org/293133007/diff/1/runtime/vm/profiler.cc
File runtime/vm/profiler.cc (right):

https://codereview.chromium.org/293133007/diff/1/runtime/vm/profiler.cc#newco...
runtime/vm/profiler.cc:1691: const intptr_t gap =
#ifdef PLATFORM_WINDOWS
const intptr_t gap = (original_fp_ & kPageMask) - (original_sp_ & kPageMask);
#else
const intptr_t gap = original_fp_ - original_sp_;
#endif

[Cutch, 2014-05-26 06:16:44]

On 2014/05/23 11:44:29, Cutch wrote:
> lgtm with #ifdef fix
> 
> https://codereview.chromium.org/293133007/diff/1/runtime/vm/profiler.cc
> File runtime/vm/profiler.cc (right):
> 
>
https://codereview.chromium.org/293133007/diff/1/runtime/vm/profiler.cc#newco...
> runtime/vm/profiler.cc:1691: const intptr_t gap =
> #ifdef PLATFORM_WINDOWS
> const intptr_t gap = (original_fp_ & kPageMask) - (original_sp_ & kPageMask);
> #else
> const intptr_t gap = original_fp_ - original_sp_;
> #endif

Actually, I want to tweak this more. Let's discuss before landing today.

[Anders Johnsen, 2014-05-26 08:27:55]

PTAL

https://codereview.chromium.org/293133007/diff/1/runtime/vm/profiler.cc
File runtime/vm/profiler.cc (right):

https://codereview.chromium.org/293133007/diff/1/runtime/vm/profiler.cc#newco...
runtime/vm/profiler.cc:1691: const intptr_t gap =
On 2014/05/23 11:44:29, Cutch wrote:
> #ifdef PLATFORM_WINDOWS
> const intptr_t gap = (original_fp_ & kPageMask) - (original_sp_ & kPageMask);
> #else
> const intptr_t gap = original_fp_ - original_sp_;
> #endif

Done.

[Cutch, 2014-05-26 08:33:37]

lgtm conditional on stress testing :)

[Anders Johnsen, 2014-05-26 09:13:16]

Committed patchset #2 manually as r36623 (presubmit successful).