Use compiler barrier instead of memory barrier for release/acquire atomic operations on mac.

BUG=
R=jarin@chromium.org

Review URL: https://codereview.chromium.org/694703003

Cr-Commit-Position: refs/heads/master@{#25147}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25147 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Replace C++ bitfields with our own BitFields

Shave this yak from orbit, it's the only way to be sure.

BUG=chromium:427616
LOG=n
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/700963002

Cr-Commit-Position: refs/heads/master@{#25148}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25148 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
[turbofan] optimize hot loop in ResolveControlFlow

R=jarin@chromium.org

BUG=

Review URL: https://codereview.chromium.org/694473002

Cr-Commit-Position: refs/heads/master@{#25149}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25149 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Fix fast-variants feature in test driver.

BUG=
R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/701933003

Cr-Commit-Position: refs/heads/master@{#25150}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25150 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
[turbofan] Fix deopt for assignments in non-effect context.

BUG=
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/701853002

Cr-Commit-Position: refs/heads/master@{#25151}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25151 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Skip box2d for gc stress.

TBR=bmeurer@chromium.org, ishell@chromium.org

Review URL: https://codereview.chromium.org/696213003

Cr-Commit-Position: refs/heads/master@{#25152}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25152 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
HPhis with HParameter inputs must have Tagged representation

BUG=v8:3670
LOG=n
R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/702053002

Cr-Commit-Position: refs/heads/master@{#25153}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25153 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Make merge_to_branch more git-friendly.

BUG=410721
LOG=n
TEST=script_test.py
R=tandrii@chromium.org
TBR=tandrii@chromium.org

Review URL: https://codereview.chromium.org/702843002

Cr-Commit-Position: refs/heads/master@{#25154}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25154 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Parser & internalization fix: ensure no heap allocs during GetString(Handle<String>).

The bug has always been there: when the parser is operating in the "immediately
internalize" mode and calls GetString, we get FlatContent of a string and then
do heap allocation.

The bug was uncovered by https://codereview.chromium.org/693803004/ (which put
the parser to the "immediately internalize" mode more often), but looking at the
code, it's possible that it can happen in other cases too.

This CL makes AstValueFactory handle this situation gracefully: it won't try to
internalize inside GetString(Handle<String>); it's unnecessary anyway since we
have the Handle<String> already.

R=rossberg@chromium.org
BUG=

Review URL: https://codereview.chromium.org/699343004

Cr-Commit-Position: refs/heads/master@{#25155}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25155 ce2b1a6d-e550-0410-aec6-3dcde31c8c00