Check for empty handle in JSON stringifier

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/22420004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16106 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
MIPS: First implementation of allocation elimination in Hydrogen.

Port r16098 (328ff5f7)

Original commit message:
This change implements a simple data-flow analysis pass over captured
objects to the existing escape analysis. It tracks the state of values
in the Hydrogen graph through CapturedObject marker instructions that
are used to construct an appropriate translation for the deoptimizer to
be able to materialize these objects again.

This can be considered a combination of scalar replacement of loads and
stores on captured objects and sinking of unused allocations.

TEST=mjsunit/compiler/escape-analysis

BUG=

Review URL: https://codereview.chromium.org/22580003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16107 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
mod does not rely on a fixed register anymore, the arguments are passed via the stack.

BUG=
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/21495005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16108 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Support idle time in CPU profiler

This change provides an API for the embedder to tell CPU profiler if it is idle or busy with some task. This way we can discriminate between idle time and some native code execution.

BUG=268947
R=alph@chromium.org, yangguo@chromium.org

Review URL: https://codereview.chromium.org/22412003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16109 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Revert "mod does not rely on a fixed register anymore, the arguments are passed via the stack."
Due to buildbot failures.

BUG=
R=danno@chromium.org

Review URL: https://chromiumcodereview.appspot.com/22474007

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16110 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Fix Object.freeze, Object.observe wrt CountOperation and CompoundAssignment.

BUG=2774,2779
R=adamk@chromium.org

Review URL: https://chromiumcodereview.appspot.com/22562004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16111 ce2b1a6d-e550-0410-aec6-3dcde31c8c00