Simplify isolates access during stack iteration (WAS: Move SafeStackFrameIterator::active_count_...)

Simplify isolates access during stack iteration (WAS: Move SafeStackFrameIterator::active_count_...)

While trying to fix Mac and Windows versions for this change:
http://codereview.chromium.org/6771047/, I figured out, that we
already store an isolate in StackFrameIterator, so we can use it in
frame objects, instead of requiring it from caller.

I've changed iterators usage to the following scheme: whenever a
caller maintains an isolate pointer, it just passes it to stack
iterator, and no more worries about passing it to frame content
accessors.  If a caller uses current isolate, it can omit passing it
to iterator, in this case, an iterator will use the current isolate,
too.

There was a special case with LiveEdit, which creates
detached copies of frame objects.

R=vitalyr@chromium.org
BUG=none
TEST=none

Committed: http://code.google.com/p/v8/source/detail?r=7499

[Vitaly Repeshko, 2011-04-04 20:37:08]

LGTM with the comments addressed.


-- Vitaly

http://codereview.chromium.org/6794019/diff/2002/src/frames-inl.h
File src/frames-inl.h (right):

http://codereview.chromium.org/6794019/diff/2002/src/frames-inl.h#newcode97
src/frames-inl.h:97: inline Isolate* StackFrame::isolate() const {
I'm not convinced we need this tricky stuff. Usually we only create one frame
object per type and reuse them while a stack iterator is active, and we don't
care that much about the memory usage in the live edit case. Please use an
explicit isolate field.

http://codereview.chromium.org/6794019/diff/2002/src/frames.cc
File src/frames.cc (right):

http://codereview.chromium.org/6794019/diff/2002/src/frames.cc#newcode425
src/frames.cc:425: if (SafeStackFrameIterator::is_active(isolate))
nit: Format one a single line if fits, use {} otherwise.

[mnaganov (inactive), 2011-04-05 08:28:23]

http://codereview.chromium.org/6794019/diff/2002/src/frames-inl.h
File src/frames-inl.h (right):

http://codereview.chromium.org/6794019/diff/2002/src/frames-inl.h#newcode97
src/frames-inl.h:97: inline Isolate* StackFrame::isolate() const {
On 2011/04/04 20:37:08, Vitaly Repeshko wrote:
> I'm not convinced we need this tricky stuff. Usually we only create one frame
> object per type and reuse them while a stack iterator is active, and we don't
> care that much about the memory usage in the live edit case. Please use an
> explicit isolate field.

I agree. I was in a premature optimization mood. Split into two fields.

http://codereview.chromium.org/6794019/diff/2002/src/frames.cc
File src/frames.cc (right):

http://codereview.chromium.org/6794019/diff/2002/src/frames.cc#newcode425
src/frames.cc:425: if (SafeStackFrameIterator::is_active(isolate))
On 2011/04/04 20:37:08, Vitaly Repeshko wrote:
> nit: Format one a single line if fits, use {} otherwise.

Done.