erikcorry@chromium.org suggested digging into v8 handle usage. Found potential scopes in ast.cc and runtime-literals.cc and added tests.

The runtime-literals.cc change reduces peak handles in imaging-darkroom.js from 1,282,610 to 428,218. The ast.cc change reduces the peak handles in string-tagcloud.js from 80,738 to 8,176.

No significant handle count issues found with major websites, but substantial savings on some benchmarks and demos:

Kraken's imaging-darkroom.js down from 1,282,610 to 428,218 due to runtime-literals.cc scope.
SunSpider's string-tagcloud.js down from 80,738 to 8.176 due to ast.cc

http://www.flohofwoe.net/demos/dragons_asmjs.html (738,906 -> 478,296)
http://www.flohofwoe.net/demos/instancing_asmjs.html (737,884 -> 477,274)
https://dl.dropboxusercontent.com/u/16662598/Ports/DOSBox-web/doom.html?engine=dosbox-growth.js (1,724,114 -> 1,087,408)
https://kripken.github.io/ammo.js/examples/new/ammo.html (175,784 -> 142,058)

BUG=

Review URL: https://codereview.chromium.org/1185633002

Cr-Commit-Position: refs/heads/master@{#29155}

BUG=

Review URL: https://codereview.chromium.org/1195823002

Cr-Commit-Position: refs/heads/master@{#29154}

R=rossberg@chromium.org
BUG=v8:4194
LOG=N

Review URL: https://codereview.chromium.org/1191303002

Cr-Commit-Position: refs/heads/master@{#29153}

BUG=

Review URL: https://codereview.chromium.org/1191313003

Cr-Commit-Position: refs/heads/master@{#29152}

Each Script object now keeps a WeakFixedArray of SharedFunctionInfo
objects created from this script.

This way, when compiling a function, we do not create duplicate shared
function info objects when recompiling with either compiler.

This fixes a class of issues in the debugger, where we set break points
on one shared function info, but functions from duplicate shared function
infos are not affected.

LOG=N
BUG=v8:4132

Review URL: https://codereview.chromium.org/1183733006

Cr-Commit-Position: refs/heads/master@{#29151}

BUG=v8:4007
LOG=N
R=rossberg@chromium.org, arv@chromium.org
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:linux_chromium_rel_ng;tryserver.blink:linux_blink_rel

Committed: https://crrev.com/12e194860a56d47a10d89ae34761a4af6b6166bb
Cr-Commit-Position: refs/heads/master@{#29118}

Review URL: https://codereview.chromium.org/1191003003

Cr-Commit-Position: refs/heads/master@{#29150}

R=jarin@chromium.org

Review URL: https://codereview.chromium.org/1196613003

Cr-Commit-Position: refs/heads/master@{#29149}

BUG=
LOG=N

Review URL: https://codereview.chromium.org/1192383003

Cr-Commit-Position: refs/heads/master@{#29148}

BUG=v8:3809
LOG=n
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/1196623002

Cr-Commit-Position: refs/heads/master@{#29147}

The three different concerns that the ControlReducer used to deal with
are now properly separated into

  a.) DeadCodeElimination, which is a regular AdvancedReducer, that
      propagates Dead via control edges,
  b.) CommonOperatorReducer, which does strength reduction on common
      operators (i.e. Branch, Phi, and friends), and
  c.) GraphTrimming, which removes dead->live edges from the graph.

This will make it possible to run the DeadCodeElimination together with
other passes that actually introduce Dead nodes, i.e. typed lowering;
and it opens the door for general inlining without two stage fix point
iteration.

To make the DeadCodeElimination easier and more uniform, we basically
reverted the introduction of DeadValue and DeadEffect, and changed the
Dead operator to produce control, value and effect. Note however that
this is not a requirement, but merely a way to make dead propagation
easier and more uniform. We could always go back and decide to have
different Dead operators if some other change requires that.

Note that there are several additional opportunities for cleanup now,
i.e. OSR deconstruction could be a regular reducer now, and we don't
need to use TheHole as dead value marker in the GraphReducer. And we can
actually run the dead code elimination together with the other passes
instead of using separate passes over the graph.  We will do this in
follow up CLs.

R=jarin@chromium.org, mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/1193833002

Cr-Commit-Position: refs/heads/master@{#29146}

R=jarin@chromium.org
TEST=cctest/test-run-deopt/DeoptExceptionHandlerFinally
BUG=v8:4195
LOG=N

Review URL: https://codereview.chromium.org/1189373003

Cr-Commit-Position: refs/heads/master@{#29145}

BUG=

Review URL: https://codereview.chromium.org/1193673002

Cr-Commit-Position: refs/heads/master@{#29144}

Added: JIC, BEQZC, JIALC, LDPC, LWPC, ALUIPC, ADDIUPC, ALIGN/DAILGN, LWUPC,
AUIPC, BC, BALC. Additional fixed compact branch offset.

TEST=test-assembler-mips[64]/r6_align, r6_dalign, r6_aluipc, r6_lwpc, r6_jic,
                             r6_beqzc, r6_jialc, r6_addiupc, r6_ldpc, r6_lwupc,
                             r6_auipc, r6_bc, r6_balc
BUG=

Review URL: https://codereview.chromium.org/1195793002

Cr-Commit-Position: refs/heads/master@{#29143}

Don't roundtrip to JS to update the length. This is 1) faster (although we don't care) and 2) avoids stackchecks that otherwise make the .Assert fail on stack overflow.

BUG=chromium:502147
LOG=n

Review URL: https://codereview.chromium.org/1189423002

Cr-Commit-Position: refs/heads/master@{#29142}

Adds a script for converting gc nvp output into csv files. Factors out common
code in gc-nvp-trace-processor.py to gc_nvp_common.py to be shared by both
scripts. Fixes a couple of issues in nvp parsing code.

Review URL: https://codereview.chromium.org/1175113008

Cr-Commit-Position: refs/heads/master@{#29141}

Revert of [release-tools] Fix possible race condition in retrieval of latest rolled version (patchset #2 id:20001 of https://codereview.chromium.org/1186393007/)

Reason for revert:
Build slave fetches git repo from cache not from real repo.

Original issue's description:
> [release-tools] Fix possible race condition in retrieval of latest rolled version
>
> R=machenbach@chromium.org
> BUG=
> NOTRY=true
>
> Committed: https://crrev.com/5d2a85b2450f9f88a94949052c5b055c1304b9b8
> Cr-Commit-Position: refs/heads/master@{#29137}

TBR=machenbach@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/1195693003

Cr-Commit-Position: refs/heads/master@{#29140}

BUG=v8:4137
LOG=n

Review URL: https://codereview.chromium.org/1196543003

Cr-Commit-Position: refs/heads/master@{#29139}

BUG=chromium:502176
LOG=n

Review URL: https://codereview.chromium.org/1193843002

Cr-Commit-Position: refs/heads/master@{#29138}

R=machenbach@chromium.org
BUG=
NOTRY=true

Review URL: https://codereview.chromium.org/1186393007

Cr-Commit-Position: refs/heads/master@{#29137}

R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/1189183002

Cr-Commit-Position: refs/heads/master@{#29136}

R=mstarzinger@chromium.org
BUG=chromium:500980
LOG=N

Review URL: https://codereview.chromium.org/1191263002

Cr-Commit-Position: refs/heads/master@{#29135}

Not doing so could result in this scenario:
- We ensure that the string table is large enough. It is.
- We compile code stubs, which triggers a GC.
- The GC clears string table entries.
- This increases the number of deleted entries in the table.
- When the deserializer hooks up internalized strings into the
  table, we ensure that the table is large enough every time.
- Due to changed number of deleted entries, the heuristic
  decides to expand the string table.
- Allocation during deserialization causes assertion to fail.

BUG=chromium:502085
LOG=N

Review URL: https://codereview.chromium.org/1197633002

Cr-Commit-Position: refs/heads/master@{#29134}

port 41405c04 (r29122).

   fix spelling error in r29122.

BUG=

Review URL: https://codereview.chromium.org/1197593002

Cr-Commit-Position: refs/heads/master@{#29133}

We block constant pool up to the call stub instruction, but the check for code size
includes the next instruction after the call instruction. That instruction can
emit constant pool.

BUG=chromium:500831
LOG=NO
TEST=mjsunit/regress/regress-500831

Review URL: https://codereview.chromium.org/1189123003

Cr-Commit-Position: refs/heads/master@{#29132}

Rolling v8/build/gyp to 5122240c5e5c4d8da12c543d82b03d6089eb77c5

Rolling v8/third_party/icu to 00af1a4e512477e48ba3d5efc97adbc95462685e

Rolling v8/tools/clang to d2b4eddd701ff0265124147bcb0a65f32273f06b

TBR=machenbach@chromium.org

Review URL: https://codereview.chromium.org/1192743002

Cr-Commit-Position: refs/heads/master@{#29131}

Revert of Add d8 API for spawning function on a new thread. (patchset #6 id:100001 of https://codereview.chromium.org/1185643004/)

Reason for revert:
Fails on V8 Win32 - nosnap - shared (http://build.chromium.org/p/client.v8/builders/V8%20Win32%20-%20nosnap%20-%20shared/builds/7427)

Fails on V8 Arm - debug builder (http://build.chromium.org/p/client.v8/builders/V8%20Arm%20-%20debug%20builder/builds/4361)

Fails on V8 Linux - shared (http://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20shared/builds/4430)

Original issue's description:
> Add d8 API for spawning function on a new thread.
>
> This API closely matches the Worker API. The differences:
>
> 1) The argument to the Worker constructor is a function to run, not a script.
> 2) Receiving a message from a worker is a synchronous API (as there is no event
> loop).
>
> The serialization done here is not robust as the real DOM implementation. For
> example, recursive data structures or otherwise duplicated objects are not
> allowed.
>
> BUG=none
> R=jochen@chromium.org
> LOG=n
>
> Committed: https://crrev.com/3d98b956b56fa283b40913788ff760022d478812
> Cr-Commit-Position: refs/heads/master@{#29126}

TBR=jochen@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=none

Review URL: https://codereview.chromium.org/1192193002

Cr-Commit-Position: refs/heads/master@{#29130}

BUG=v8:4137
LOG=n

Review URL: https://codereview.chromium.org/1180753005

Cr-Commit-Position: refs/heads/master@{#29129}

TEST=cctest/test-simplified-lowering/RunAccessTests_float64
BUG=

Review URL: https://codereview.chromium.org/1182713004

Cr-Commit-Position: refs/heads/master@{#29128}

The ordering of the "IsArray()" check for IsConcatSpreadable() was incorrect previously --- IsArray() is only used if Get(O, @@isConcatSpreadable) is undefined. Without this fix, it's not possible for Array subclasses to opt out of spreading

22.1.3.1.1 http://www.ecma-international.org/ecma-262/6.0/#sec-isconcatspreadable

BUG=v8:3764
LOG=N
R=arv@chromium.org, dslomov@chromium.org, rossberg@chromium.org

Review URL: https://codereview.chromium.org/1192153002

Cr-Commit-Position: refs/heads/master@{#29127}

This API closely matches the Worker API. The differences:

1) The argument to the Worker constructor is a function to run, not a script.
2) Receiving a message from a worker is a synchronous API (as there is no event
loop).

The serialization done here is not robust as the real DOM implementation. For
example, recursive data structures or otherwise duplicated objects are not
allowed.

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

Review URL: https://codereview.chromium.org/1185643004

Cr-Commit-Position: refs/heads/master@{#29126}

Reason for revert:
[Sheriff] Breaks layout tests. Please submit a needsmanualrebaseline change on the blink side for the expectations if intended.

E.g.
http://build.chromium.org/p/client.v8.fyi/builders/V8-Blink%20Linux%2064/builds/545

Original issue's description:
> Ship arrow functions
>
> R=rossberg@chromium.org
> LOG=Y
> BUG=v8:2700
>
> Committed: https://crrev.com/541b6c39e0ecae1c070f51fae8e9e3dab18d278c
> Cr-Commit-Position: refs/heads/master@{#29119}

TBR=rossberg@chromium.org,wingo@igalia.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:2700

Review URL: https://codereview.chromium.org/1182053013

Cr-Commit-Position: refs/heads/master@{#29125}

Revert of [es6] ship Object.assign (patchset #2 id:20001 of https://codereview.chromium.org/1191003003/)

Reason for revert:
Seems to break asan somehow

Original issue's description:
> [es6] ship Object.assign
>
> BUG=v8:4007
> LOG=N
> R=rossberg@chromium.org, arv@chromium.org
> CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:linux_chromium_rel_ng;tryserver.blink:linux_blink_rel
>
> Committed: https://crrev.com/12e194860a56d47a10d89ae34761a4af6b6166bb
> Cr-Commit-Position: refs/heads/master@{#29118}

TBR=arv@chromium.org,dslomov@chromium.org,rossberg@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4007

Review URL: https://codereview.chromium.org/1191593005

Cr-Commit-Position: refs/heads/master@{#29124}

Revert of Re-land new insertion write barrier. (patchset #3 id:40001 of https://codereview.chromium.org/1153233003/)

Reason for revert:
Deoptimizer crashes.

Original issue's description:
> Re-land new insertion write barrier.
>
> BUG=
>
> Committed: https://crrev.com/72f850458cb530d871cf3fb6442660555dc51bc2
> Cr-Commit-Position: refs/heads/master@{#29052}

TBR=ulan@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/1176243015

Cr-Commit-Position: refs/heads/master@{#29123}

Revert of Revert of [strong] Implement strong mode restrictions on property access (patchset #1 id:1 of https://codereview.chromium.org/1189153002/)

Reason for revert:
Issue was ultimately caused/fixed by https://codereview.chromium.org/1194673002/

Original issue's description:
> Revert of [strong] Implement strong mode restrictions on property access (patchset #23 id:460001 of https://codereview.chromium.org/1168093002/)
>
> Reason for revert:
> Speculative revert, maybe breaks GC-stress
>
> http://build.chromium.org/p/client.v8/builders/V8%20Linux64%20GC%20Stress%20-%20custom%20snapshot/builds/808
>
> Original issue's description:
> > [strong] Implement strong mode restrictions on property access
> >
> > Implements the strong mode proposal's restrictions on property access.
> >
> > To be fully explored in a followup: proxies, interceptors, access checks, load from super
> >
> > BUG=v8:3956
> > LOG=N
> >
> > Committed: https://crrev.com/85dbfb9a389e7b21bd2a63862202ee97fc5d7982
> > Cr-Commit-Position: refs/heads/master@{#29109}
>
> TBR=rossberg@chromium.org,mvstanton@chromium.org,mstarzinger@chromium.org,verwaest@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=v8:3956
>
> Committed: https://crrev.com/407657b706711fd5f8d417841e24b284886f3776
> Cr-Commit-Position: refs/heads/master@{#29115}

TBR=rossberg@chromium.org,mvstanton@chromium.org,mstarzinger@chromium.org,verwaest@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:3956
LOG=N

Review URL: https://codereview.chromium.org/1185343005

Cr-Commit-Position: refs/heads/master@{#29122}

Revert of Replace ad-hoc weakness in transition array with WeakCell. (patchset #5 id:80001 of https://codereview.chromium.org/1157943003/)

Reason for revert:
Breaks descriptor array clearing.

Original issue's description:
> Replace ad-hoc weakness in transition array with WeakCell.
>
> BUG=
>
> Committed: https://crrev.com/885455e99de817f86a0b5df2dc0d932cfc179749
> Cr-Commit-Position: refs/heads/master@{#29083}

TBR=jkummerow@chromium.org,hpayer@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/1194673002

Cr-Commit-Position: refs/heads/master@{#29121}

RegExpExecStub pushes callee-saved registers without setting up a frame. This confuses the stack iterator.

Other architectures do not save these registers.

BUG=chromium:487981
LOG=NO
TEST=mjsunit/regress/regress-487981

Review URL: https://codereview.chromium.org/1183593005

Cr-Commit-Position: refs/heads/master@{#29120}

R=rossberg@chromium.org
LOG=Y
BUG=v8:2700

Review URL: https://codereview.chromium.org/1187173004

Cr-Commit-Position: refs/heads/master@{#29119}

BUG=v8:4007
LOG=N
R=rossberg@chromium.org, arv@chromium.org
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:linux_chromium_rel_ng;tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1191003003

Cr-Commit-Position: refs/heads/master@{#29118}

R=machenbach@chromium.org

Review URL: https://codereview.chromium.org/1189943005

Cr-Commit-Position: refs/heads/master@{#29117}

BUG=v8:4137
LOG=n

Review URL: https://codereview.chromium.org/1191813003

Cr-Commit-Position: refs/heads/master@{#29116}