Speed up function deoptimization by avoiding quadratic pass over optimized function list.

Speed up function deoptimization by avoiding quadratic pass over optimized function list.

R=danno@chromium.org
BUG=155270
Committed: https://code.google.com/p/v8/source/detail?r=12780

[ulan, 2012-10-19 16:48:08]

PTAL

[danno, 2012-10-21 19:56:15]

LGTM with comments

http://codereview.chromium.org/11189091/diff/1/src/deoptimizer.cc
File src/deoptimizer.cc (right):

http://codereview.chromium.org/11189091/diff/1/src/deoptimizer.cc#newcode1454
src/deoptimizer.cc:1454: while (!current->IsUndefined()) {
Why not current != undefined, if you already have it?

http://codereview.chromium.org/11189091/diff/1/src/deoptimizer.cc#newcode1469
src/deoptimizer.cc:1469: if (head !=
context->get(Context::OPTIMIZED_FUNCTIONS_LIST)) {
If this extra compare just to avoid a write barrier? Otherwise, why not simply
always set the head?

http://codereview.chromium.org/11189091/diff/1/src/deoptimizer.cc#newcode1485
src/deoptimizer.cc:1485: while (!current->IsUndefined()) {
Why not current != undefined, if you already have it?

[ulan, 2012-10-22 08:39:56]

Addressed comments, landing.

http://codereview.chromium.org/11189091/diff/1/src/deoptimizer.cc
File src/deoptimizer.cc (right):

http://codereview.chromium.org/11189091/diff/1/src/deoptimizer.cc#newcode1454
src/deoptimizer.cc:1454: while (!current->IsUndefined()) {
On 2012/10/21 19:56:15, danno wrote:
> Why not current != undefined, if you already have it?

Done.

http://codereview.chromium.org/11189091/diff/1/src/deoptimizer.cc#newcode1469
src/deoptimizer.cc:1469: if (head !=
context->get(Context::OPTIMIZED_FUNCTIONS_LIST)) {
On 2012/10/21 19:56:15, danno wrote:
> If this extra compare just to avoid a write barrier? Otherwise, why not simply
> always set the head?
Yep, I think head will be unchanged most of the time.

http://codereview.chromium.org/11189091/diff/1/src/deoptimizer.cc#newcode1485
src/deoptimizer.cc:1485: while (!current->IsUndefined()) {
On 2012/10/21 19:56:15, danno wrote:
> Why not current != undefined, if you already have it?

Done.