Eliminate most of the jump target jumping, branching, and binding...

Eliminate most of the jump target jumping, branching, and binding
overhead on the ARM platform.

Because virtual frames are always in memory, there is no work to be
done for control flow except in the case of breaking or continuing
when there is extra statement state on the stack.


Committed: http://code.google.com/p/v8/source/detail?r=2655

[Erik Corry, 2009-08-10 10:56:45]

LGTM

http://codereview.chromium.org/165230/diff/1/7
File src/arm/jump-target-arm.cc (right):

http://codereview.chromium.org/165230/diff/1/7#newcode65
Line 65: // The predicate is_linked() should now be true.  The implementation
This comment doesn't explain itself very well.

http://codereview.chromium.org/165230/diff/1/7#newcode166
Line 166: int count = cgen()->frame()->height() - expected_height_;
Should we assert that count is positive?

[Kevin Millikin (Chromium), 2009-08-10 11:11:31]

http://codereview.chromium.org/165230/diff/1/7
File src/arm/jump-target-arm.cc (right):

http://codereview.chromium.org/165230/diff/1/7#newcode65
Line 65: // The predicate is_linked() should now be true.  The implementation
On 2009/08/10 10:56:45, Erik Corry wrote:
> This comment doesn't explain itself very well.

Reworded:

"The predicate is_linked() should be made true.  Its implementation detects the
presence of a frame pointer in the reaching_frames_ list."

http://codereview.chromium.org/165230/diff/1/7#newcode166
Line 166: int count = cgen()->frame()->height() - expected_height_;
On 2009/08/10 10:56:45, Erik Corry wrote:
> Should we assert that count is positive?

Yea verily.  Even better it should go in VirtualFrame::Drop.  I've added it for
all platforms.