Turn mark deoptimize on undefined into a proper HPhase.

Turn mark deoptimize on undefined into a proper HPhase.

This patch also removes the implicit recursion on phi operands,
using a loop and a worklist instead, to avoid potential stack
overflows.

R=dslomov@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=15952

[Benedikt Meurer, 2013-07-29 13:00:18]

PTAL

[Dmitry Lomov (no reviews), 2013-07-29 15:31:47]

https://codereview.chromium.org/21065003/diff/4001/src/hydrogen-mark-deoptimi...
File src/hydrogen-mark-deoptimize.cc (right):

https://codereview.chromium.org/21065003/diff/4001/src/hydrogen-mark-deoptimi...
src/hydrogen-mark-deoptimize.cc:53: while (!worklist.is_empty()) {
This fusion of two methods into one using the same worklist is a bit hard to
grok. Can we extract the second loop into a method and call it for each phi in
the phi list? (just the way the code was structured before)

[Benedikt Meurer, 2013-07-29 19:38:52]

PTAL

https://codereview.chromium.org/21065003/diff/4001/src/hydrogen-mark-deoptimi...
File src/hydrogen-mark-deoptimize.cc (right):

https://codereview.chromium.org/21065003/diff/4001/src/hydrogen-mark-deoptimi...
src/hydrogen-mark-deoptimize.cc:53: while (!worklist.is_empty()) {
On 2013/07/29 15:31:48, Dmitry Lomov (chromium) wrote:
> This fusion of two methods into one using the same worklist is a bit hard to
> grok. Can we extract the second loop into a method and call it for each phi in
> the phi list? (just the way the code was structured before)

Done. Also refactored the common AddToWorklist functionality into a separate
method.

[Dmitry Lomov (no reviews), 2013-07-30 09:05:24]

https://codereview.chromium.org/21065003/diff/15001/src/hydrogen-mark-deoptim...
File src/hydrogen-mark-deoptimize.cc (right):

https://codereview.chromium.org/21065003/diff/15001/src/hydrogen-mark-deoptim...
src/hydrogen-mark-deoptimize.cc:51: void
HMarkDeoptimizeOnUndefinedPhase::AddToWorklist(HPhi* phi) {
Any reason to have AddToWorklist function at all? I would do it this way:
- Rename ProcessWorklist into ProcessPhi
- Pass phi to ProcessPhi and make worklist local to ProcessPhiTree
- Remove global worklist

[Benedikt Meurer, 2013-07-30 09:59:10]

PTAL

https://codereview.chromium.org/21065003/diff/15001/src/hydrogen-mark-deoptim...
File src/hydrogen-mark-deoptimize.cc (right):

https://codereview.chromium.org/21065003/diff/15001/src/hydrogen-mark-deoptim...
src/hydrogen-mark-deoptimize.cc:51: void
HMarkDeoptimizeOnUndefinedPhase::AddToWorklist(HPhi* phi) {
On 2013/07/30 09:05:24, Dmitry Lomov (chromium) wrote:
> Any reason to have AddToWorklist function at all? I would do it this way:
> - Rename ProcessWorklist into ProcessPhi
> - Pass phi to ProcessPhi and make worklist local to ProcessPhiTree
> - Remove global worklist

As discussed offline: The idea is to avoid allocating a new ZoneList for every
phi with an affected use. The way its done now reuses the same ZoneList. I'll
merge the AddToWorklist and ProcessWorklist methods into a single ProcessPhi
method, using the member ZoneList as optimization.

[Dmitry Lomov (no reviews), 2013-07-30 10:07:47]

lgtm

[Benedikt Meurer, 2013-07-30 10:25:27]

Committed patchset #6 manually as r15952 (presubmit successful).