Add %_DebugBreakInOptimizedCode() pseudo function call

Add %_DebugBreakInOptimizedCode() pseudo function call to insert int3/stop instructions into optimized code

R=mstarzinger@chromium.org

Committed: http://code.google.com/p/v8/source/detail?r=15392

[Jakob Kummerow, 2013-06-26 12:02:01]

PTAL.

Happy to rename the thing if you have a better idea. "%_BreakInOptimizedCode"
maybe?

[Michael Starzinger, 2013-06-26 14:16:15]

LGTM with a comment.

https://codereview.chromium.org/17870002/diff/1/src/runtime.h
File src/runtime.h (right):

https://codereview.chromium.org/17870002/diff/1/src/runtime.h#newcode601
src/runtime.h:601: F(HDebugBreak, 0, 0)
As discussed offline: This only affects optimized code and not full code on
purpose and I can see the use cases for that. But I would agree with your
suggestion to make the name more expressive in that regard. How about
"DebugBreakInOptimizedCode"? The hypothetical counterpart for full code would
then be "DebugBreakInFullCode". I am also fine with s/DebugBreak/Break/ if you
prefer that.

[Michael Starzinger, 2013-06-26 15:32:57]

Still LGTM.

[Jakob Kummerow, 2013-06-28 15:48:45]

Committed patchset #3 manually as r15392 (presubmit successful).