Arithmetic right shifting is *not* division in two's complement
representation, only in one's complement. So we convert to one's
complement, shift, and go back to two's complement. By permutating the
last steps, one can get efficient branch-free code. This insight comes
from the paleozoic era of computer science, see the paper from 1976:

   Guy Lewis Steele Jr.: "Arithmetic Shifting Considered Harmful"
   ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-378.pdf

This results in better and more correct code than our previous
"neg/shift/neg" dance.

LOG=y
BUG=v8:3151
R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/166793002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19434 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=jarin@chromium.org
BUG=v8:2938
LOG=N

Review URL: https://codereview.chromium.org/169513002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19433 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

This reverts commit r19410.

TBR=verwaest@chromium.org

Review URL: https://codereview.chromium.org/169113005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19432 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

BUG=
R=dcarney@chromium.org

Review URL: https://codereview.chromium.org/163963003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19431 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

BUG=
R=dcarney@chromium.org

Review URL: https://codereview.chromium.org/170343002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19430 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=ulan@chromium.org

Review URL: https://codereview.chromium.org/169543002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19429 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

This is mostly register renaming, and a minor optimization merging two TBZ into
one TST and BNE.

R=jochen@chromium.org

Review URL: https://codereview.chromium.org/166833002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19428 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/168983006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19427 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Inputs should always be 32bit

BUG=none
R=m.m.capewell@googlemail.com, ulan@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/167123004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19426 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

We don't run tests yet because even in release mode, this will take a
considerable amount of time.

BUG=none
R=ulan@chromium.org, machenbach@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/169303006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19425 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/170263002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19424 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Causing Layout test crashes

TBR=verwaest@chromium.org

Review URL: https://codereview.chromium.org/170253002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19423 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Port r19406 (4eab88a)

BUG=
R=gergely@homejinni.com

Review URL: https://codereview.chromium.org/169243003

Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19421 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=danno@google.com

Review URL: https://codereview.chromium.org/169863002

Patch from Ulan Degenbaev <ulan@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19420 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Causes a64 debug asserts

TBR=jacob.bramley@arm.com,ulan@chromium.org

Review URL: https://codereview.chromium.org/169303007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19419 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

TBR=jochen@chromium.org

BUG=

Review URL: https://codereview.chromium.org/169793002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19418 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Notes:
- We use simple recursion to keep track of how many "new" operators we have seen
  and where.
- This makes the self-baked stack class PositionStack in parser.cc unnecessary.
- Now the logic is also unified between Parser and PreParser.
- This is a fixed version of r19386.

R=ulan@chromium.org
BUG=v8:3126
LOG=N

Review URL: https://codereview.chromium.org/168583008

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19417 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

It turned out that JSArrayBuffer's may share their backing_store so
the backing_store should go through hash map registration just like
other heap objects, so they won't be reported twice.

BUG=341741
LOG=N
R=dslomov@chromium.org, yurys@chromium.org

Review URL: https://codereview.chromium.org/166993002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19416 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=jochen@chromium.org

BUG=

Review URL: https://codereview.chromium.org/169523005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19415 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Added support for truncating DoubleToIStub and reorganize the macro-assembler
dToI operations to do the fast-path inline and the slow path by calling the
stub.

This a port essentially a port of https://codereview.chromium.org/23129003/.

R=jacob.bramley@arm.com, ulan@chromium.org

Review URL: https://codereview.chromium.org/160423002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19414 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

BUG=
R=titzer@chromium.org

Review URL: https://codereview.chromium.org/167893007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19413 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

This reverts commit r19402

R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/169713002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19412 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Use a dedicated BuildLoadNamedField() with PropertyAccessInfo,
similar to BuildStoreNamedField() for optimized graph building,
and a dedicated BuildLoadNamedField() for the code stubs, and
don't depend on FLAG_track_double_fields during code generation.

R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/168583006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19411 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/169363002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19410 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=dcarney@chromium.org

Review URL: https://codereview.chromium.org/166233004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19409 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

For some reason, the compiler cannot deduce the array bounds in opt
debug mode. An explicit check makes it happy.

BUG=none
R=ulan@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/169473003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19408 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

LOG=N
BUG=344239
R=dslomov@chromium.org, yurys@chromium.org

Review URL: https://codereview.chromium.org/169393004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19407 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=verwaest@chromium.org

BUG=

Review URL: https://codereview.chromium.org/169353002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19406 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

BUG=
R=mvstanton@chromium.org, ulan@chromium.org

Review URL: https://codereview.chromium.org/169563002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19404 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

This addresses several TODOs:
  - Push and Pop requests can be queued up so that arrays of Registers
    can be pushed efficiently, with just one PrepareForPush/Pop.
  - PushMultipleTimes now takes an Operand. This allows variable-length
    arguments arrays to be initialized, for example.
  - A NoUseRealAbortsScope has been added to Abort so that
    AssertStackConsistency can be called from PrepareForPush without
    introducing infinite recursion.

BUG=
R=ulan@chromium.org

Review URL: https://codereview.chromium.org/169533002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19403 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

From a CL by kasperl: https://codereview.chromium.org/162903004/

R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/163413003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19402 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=mstarzinger@chromium.org
BUG=328804
LOG=N

Review URL: https://codereview.chromium.org/166023003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19400 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

This commit fixes the debug build on Linux with gcc 4.6.3 and 4.7.2.

Port r19381 (5476e11b)

BUG=
R=dcarney@chromium.org, plind44@gmail.com

Review URL: https://codereview.chromium.org/167523003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19398 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=jkummerow@chromium.org
BUG=

Review URL: https://codereview.chromium.org/163623002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19396 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Port r19381 (5476e11b)

BUG=
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/163953014

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19395 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Port r19385 (27769f9)

BUG=
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/164283008

Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19394 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Port r19384 (4ba5d0d)

BUG=
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/167243003

Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19393 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Port r19380 (114a9ca)

BUG=
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/167083002

Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19392 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Port r19379 (622d830)

Original commit message:
If it's shadowed by a variable of the same name and both are forcibly
context-allocated, the function is assigned to the wrong context slot.

BUG=v8:3138
LOG=Y
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/166813002

Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19391 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/167063002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19389 ce2b1a6d-e550-0410-aec6-3dcde31c8c00