Nop bytecodes are required only for break locations in debugger. Since nop bytecode doesn't change program state we can remove all of them.

There are at least two changes which this CL produce:
- we don't provide break position when we load local variable (still provide when load variable from global),
- we don't provide break position for statements without actual break positions (e.g. "a;") - these expressions should be super rare and user always can set breakpoint before or after this statement.

More details in one pager: https://docs.google.com/a/google.com/document/d/1JXlQpfMa9vRojbE272b6GMBbrfh6m_00135iAUOJEz8/edit?usp=sharing

Bug: v8:6425
Change-Id: I4aee73d497a84f7b5d89caa6dda6d3060567dfda
Reviewed-on: https://chromium-review.googlesource.com/543161Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46742}

BUG=v8:6609

Change-Id: If4c3520fba0653e23e6d34bf344fb00cdbfc6082
Reviewed-on: https://chromium-review.googlesource.com/575049Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46741}

R=dgozman@chromium.org,machenbach@chromium.org

Bug: none
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel
Change-Id: Iccbcd55defe4f8c3ad68519ead300197e15d5d6f
Reviewed-on: https://chromium-review.googlesource.com/574635
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46740}

Revert of [api] Fix compilation error for `UNIMPLEMENTED()` method (patchset #1 id:1 of https://codereview.chromium.org/2929993003/ )

Reason for revert:
not needed any more, and contradicts our cleanup efforts: https://chromium-review.googlesource.com/c/507287/

Original issue's description:
> [api] Fix compilation error for `UNIMPLEMENTED()` method
>
> Return `nullptr` from `ArrayBuffer::Allocator::Reserve` because
> apparently not doing so results in compile errors for some people.
>
> BUG=
>
> Ref: https://github.com/nodejs/node/issues/13392
> Review-Url: https://codereview.chromium.org/2929993003
> Cr-Commit-Position: refs/heads/master@{#45886}
> Committed: https://chromium.googlesource.com/v8/v8/+/f14d1b62313329f421f12cae429673c1b13018f9

R=franzih@chromium.org,addaleax@gmail.com

Review-Url: https://codereview.chromium.org/2946933002
Cr-Commit-Position: refs/heads/master@{#46739}

- use asm_tester instead of data variable name
- directly expose Variable and Label for convenience

Change-Id: I211fe07e236f96067037ca00c1435c1491121e6b
Reviewed-on: https://chromium-review.googlesource.com/574914
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46738}

This will allow us to concurrently allocate buckets during iteration.

Bug: chromium:738865
Change-Id: I88bd1ac152d1ef8b40395f0ba3e55a7c3e82f75d
Reviewed-on: https://chromium-review.googlesource.com/575990
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46737}

TBR=ishell@chromium.org
NOTRY=true
NOTREECHECKS=true

Bug: chromium:726584
Change-Id: I204cf0e8cff403af98b2a7f156f242d67dbdaf35
Reviewed-on: https://chromium-review.googlesource.com/575929
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46736}

This allows to reuse the class e.g. in the baseline compiler.

R=titzer@chromium.org

Change-Id: I7251af16e8c74f267834a9cefb676edf3c9f3a07
Reviewed-on: https://chromium-review.googlesource.com/570020Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46735}

Change-Id: I50ae9d96545f63bdb5ca27a23ea3a04c8764678a
Reviewed-on: https://chromium-review.googlesource.com/574533Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46734}

This CL replaces some Handles which can be empty by MaybeHandle. This
documents that they can be empty, and forces a check before using them.

R=ahaas@chromium.org

Change-Id: Iefb9ae76617c45d2304b0a620dc082ab9c7b0585
Reviewed-on: https://chromium-review.googlesource.com/574593Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46733}

See https://goo.gl/6aN8xA

Bug: v8:6593
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: Ic8b0b57195d01d41591397d5d45de3f0f3ebc3d9
Reviewed-on: https://chromium-review.googlesource.com/574527Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46732}

Moves the creation of shared function infos and the scripts shared function
info array (for top-level code) to be in the FinalizeUnoptimizedCompilation
step when not compiling with Full-codegen. This is needed in order to 
avoid accessing the heap between parse and compile.

BUG=v8:5203

Change-Id: I4063bb91608fa5a0c3d3564767786776a0e4dd03
Reviewed-on: https://chromium-review.googlesource.com/571812
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46731}

en_US_POSIX is ICU's fallback locale on POSIX platforms for when it
cannot detect a default locale.  Consider it equivalent to en-US.

I won't claim this is the best possible fix but it makes the following
tests pass again for me locally:

    intl/break-iterator/default-locale
    intl/break-iterator/wellformed-unsupported-locale
    intl/collator/default-locale
    intl/collator/wellformed-unsupported-locale
    intl/date-format/default-locale
    intl/date-format/wellformed-unsupported-locale
    intl/number-format/default-locale
    intl/number-format/wellformed-unsupported-locale

R=jgruber@chromium.org

Cq-Include-Trybots: master.tryserver.v8:v8_linux_noi18n_rel_ng
Change-Id: I0e8029f4ffaf5fd3ca72a1cc5db2878891744864
Reviewed-on: https://chromium-review.googlesource.com/567981
Commit-Queue: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46730}

This refactoring makes some parameters const, and does not rely on the
fact that inputs are passed via NodeVector. Both changes are needed for
an upcoming refactoring of the wasm decoder.

R=bbudge@chromium.org

Change-Id: Ifbd6185ae9ea5a0ef526c2fd695e13e3f14475f4
Reviewed-on: https://chromium-review.googlesource.com/571004Reviewed-by: Bill Budge <bbudge@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46729}

Signature maps should only be updated, but never copied. We had a bug
because we accidentally updated a copy of the map. This refactoring
prevents any such bugs in the future, and fixes more occurences where
we accidentally copied structs containing a signature map (the move-only
constraint also extends to all structs containing a signature map).

Drive-by: Make InstanceBuilder::NeedsWrappers const.

R=titzer@chromium.org

Bug: chromium:741750
Change-Id: Id919203d8c4078e608a1163e5c790c97d06a9753
Reviewed-on: https://chromium-review.googlesource.com/571791Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46728}

This reinstates the old behavior of Error.captureStackTrace prior to
4feafee9.  Like the builtin Error constructors, captureStackTrace now formats
the stack trace lazily once it is accessed.

Bug: v8:5962
Change-Id: I03821b73d26b7b40809a1fea98f9c820bfa05d6b
Reviewed-on: https://chromium-review.googlesource.com/574530Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46727}

Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/63efa35..1808a90

Rolling v8/third_party/catapult: https://chromium.googlesource.com/external/github.com/catapult-project/catapult/+log/af47a93..44b022b

TBR=machenbach@chromium.org,hablich@chromium.org

Change-Id: Icf22a76859f0897d97ca68de61850cef1a607f26
Reviewed-on: https://chromium-review.googlesource.com/575868Reviewed-by: v8 autoroll <v8-autoroll@chromium.org>
Commit-Queue: v8 autoroll <v8-autoroll@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46726}

Change-Id: I091a1f4a1f2292b37a56520d0a5c46ac5781b459
Reviewed-on: https://chromium-review.googlesource.com/575515Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Commit-Queue: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46725}

NOTREECHECKS=true

Bug: 
Change-Id: I6c4d76be9f032d1149a5128c90995b7302c9d9b5
Reviewed-on: https://chromium-review.googlesource.com/574697
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46724}

Previously,
  ➜  v8 (master) ✔ ./out.gn/x64.optdebug/d8
  V8 version 6.1.0 (candidate)
  d8> var x = undefined
  undefined
  d8> var [a] = x
  (d8):1: TypeError: Cannot read property 'Symbol(Symbol.iterator)' of undefined
  var [a] = x
            ^
  TypeError: Cannot read property 'Symbol(Symbol.iterator)' of undefined
      at (d8):1:11

Now,
  ➜  v8 (fix-iterator) ✔ ./out.gn/x64.optdebug/d8
  V8 version 6.1.0 (candidate)
  d8> var x = undefined
  undefined
  d8> var [a] = x
  (d8):1: TypeError: x is not iterable
  var [a] = x
            ^
  TypeError: x is not iterable
      at (d8):1:11


Bug: v8:6599, v8:6513
Change-Id: I71287a19166af0289e8f7708b8f41ad003ae87ae
Reviewed-on: https://chromium-review.googlesource.com/571175
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46723}

Also, add a couple of macros to handle error cases.

R=adamk@chromium.org

Bug: chromium:744292
Change-Id: I5dcb19ce67ec1aa4318d68d973d304cb07a65b80
Reviewed-on: https://chromium-review.googlesource.com/575394
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46722}

This was previously used by our js builtins but they no longer
exist. This has been exposed to API which means we can't remove it
just yet. Moving to CPP for now to save binary size.

Bug: v8:5343
Change-Id: I2a3e5a4169310b2ba13ce13f0386336e9733d71f
Reviewed-on: https://chromium-review.googlesource.com/575024Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46721}

Now the concurrent marker skips the weak fields of AllocationSites.

BUG=chromium:694255

Change-Id: If920b6a14fa12c3a90ab0d283e22988ccbd48c0e
Reviewed-on: https://chromium-review.googlesource.com/574907
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46720}

This reverts commit a72b2f88.

Reason for revert: Breaks https://build.chromium.org/p/client.v8.ports/builders/V8%20Linux%20-%20arm64%20-%20sim%20-%20debug/builds/7093

Original change's description:
> [arm] Restrict grouping pushes before a TailCall to registers only
> 
> We optimize parallel moves performed before a TailCall by grouping adjacent
> pushes. This way, we may use a single instruction to push multiple registers at
> once. However, we also have support for pushing immediates and stack slots for
> which the benefit is questionnable therefore this patch removes support for
> them.
> 
> Concerning immediate pushes, it looks like a mistake since we do not have
> support for this case in `AssembleMove` so this patch removes it. Furthermore,
> if we add a test for this case, we see that a `push ip` instruction is
> generated, effectively pushing whatever was in `ip` at the time instead of
> pushing a constant.
> 
> Concerning stack slot pushes, we generate a more or less equivalent sequence of
> instructions.
> 
> Finally, grouping floating point pushes is not used anywhere so this patch
> removes support for this also.
> 
> Bug: v8:6553
> Change-Id: I9b820d33361fc442dd813f66e1f96cda41009110
> Reviewed-on: https://chromium-review.googlesource.com/567191
> Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
> Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
> Cr-Commit-Position: refs/heads/master@{#46718}

TBR=danno@chromium.org,jarin@chromium.org,pierre.langlois@arm.com,bmeurer@chromium.org

Change-Id: Ib9db9e6e4f033aeea32741e04b1b884429acc800
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:6553
Reviewed-on: https://chromium-review.googlesource.com/574908Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46719}

We optimize parallel moves performed before a TailCall by grouping adjacent
pushes. This way, we may use a single instruction to push multiple registers at
once. However, we also have support for pushing immediates and stack slots for
which the benefit is questionnable therefore this patch removes support for
them.

Concerning immediate pushes, it looks like a mistake since we do not have
support for this case in `AssembleMove` so this patch removes it. Furthermore,
if we add a test for this case, we see that a `push ip` instruction is
generated, effectively pushing whatever was in `ip` at the time instead of
pushing a constant.

Concerning stack slot pushes, we generate a more or less equivalent sequence of
instructions.

Finally, grouping floating point pushes is not used anywhere so this patch
removes support for this also.

Bug: v8:6553
Change-Id: I9b820d33361fc442dd813f66e1f96cda41009110
Reviewed-on: https://chromium-review.googlesource.com/567191Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/master@{#46718}

Bug: chromium:738865
Change-Id: Ic30a3e1012771d2e37b0e10aa59ab348a40bac10
Reviewed-on: https://chromium-review.googlesource.com/574714Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46717}

Now the concurrent marker pushes these objects in the bailout worklist
so that the main thread can perform wrapper tracing.

BUG=chromium:694255

Change-Id: I64f194334458fbabf16a63a8ae570456cb5fee19
Reviewed-on: https://chromium-review.googlesource.com/574603
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46716}

Bug: chromium:738865
Change-Id: I4c8aa8c90ba401200222d95d6395c022fc023a71
Reviewed-on: https://chromium-review.googlesource.com/574535
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46715}

BUG=chromium:743622

Change-Id: Ic29a39d5976425eda2358c7e5ace0efa1b78a718
Reviewed-on: https://chromium-review.googlesource.com/574604Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46714}

Added a flag, process_size, to collect the maximum memory size used by
a test run.

Bug: 
Change-Id: I5d659ff03bfcf7ab4a868aafbda3303ffcb9fa78
Reviewed-on: https://chromium-review.googlesource.com/542415
Commit-Queue: Mircea Trofin <mtrofin@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46713}

Add a default clause to the switch statement in debug::GetBuiltin() and
abort if it is reached.

Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: I8895497b64ccd3b8eb23d281b8bca4405a5c3959
Reviewed-on: https://chromium-review.googlesource.com/574172Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: Ben Noordhuis <info@bnoordhuis.nl>
Cr-Commit-Position: refs/heads/master@{#46712}

This is the ia32 implementation of the CL
https://codereview.chromium.org/2763593002

Original message:

[wasm][arm] Add an additional stack check for functions with big frames.

Stack overflow checks are typically implemented as part of the TurboFan
graph of a function. This means that the stack check code is executed
after frame construction. When a frame is too big, though, there may not
be enough space on the stack anymore to throw the stack overflow
exception after frame construction. With this CL we do an additional
stack check before frame construction for functions with big frames.

As discussed offline with mstarzinger, I do this change currently only
for WebAssembly.

This CL contains only the changes for arm. I will do the other platforms
in separate CLs.

Bug:v8:6318

R=neis@chromium.org, titzer@chromium.org

Change-Id: Ibeedc5c4c4571cffd3a9c58016ddc44b64e2bf02
Reviewed-on: https://chromium-review.googlesource.com/568305
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46711}

This makes sure Runtime_ArrayBufferNeuter fails gracefully on array
buffers that are non-neuterable. Note that this runtime function is
whitelisted on ClusterFuzz and otherwise only used for testing.

R=cbruni@chromium.org
BUG=chromium:743215,v8:6534

Change-Id: I5069e615468f8789bf4fd87bb1e093a18bfd0347
Reviewed-on: https://chromium-review.googlesource.com/574168Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46710}

R=petermarshall@chromium.org

Change-Id: If181ed625015105f8bbabf29a9db3cfcf090b80a
Reviewed-on: https://chromium-review.googlesource.com/574235Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46709}

Bug: chromium:738865
Change-Id: Icc3e292ded7f4097ef266d8db80f273a412a8b92
Reviewed-on: https://chromium-review.googlesource.com/565718
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46708}

InstructionSelector::VisitInt32Mul

TEST=cctest/test-run-machops/RunInt32MulAndInt32AddP,mjsunit/asm/int32mod-constant

Bug: 
Change-Id: Iaccfc0d0c981e7c7e2f8b06ff3812fe60d1f85d3
Reviewed-on: https://chromium-review.googlesource.com/574367Reviewed-by: Miran Karić <Miran.Karic@imgtec.com>
Commit-Queue: Ivica Bogosavljevic <ivica.bogosavljevic@imgtec.com>
Cr-Commit-Position: refs/heads/master@{#46707}

Bug=chromium:740784
LOG=N

Change-Id: I61fe1b07426d0b1e5131687c9ce99a8dbfa09781
Reviewed-on: https://chromium-review.googlesource.com/574175
Commit-Queue: Daniel Clifford <danno@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46706}

This removes a special case for {IfSuccess} control projections from the
effect-control linearizer that is no longer needed now that such control
projections only appear in pairs.

R=jarin@chromium.org

Change-Id: I4d872ad301d09e7424b249fb7c4eb70353a9d3ff
Reviewed-on: https://chromium-review.googlesource.com/574228Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46705}

This replaces four heap allocations by one stack allocated value.

R=mstarzinger@chromium.org

Change-Id: I7d00968d7bddadb51d7c7b1f3bc5253e54c8a3f9
Reviewed-on: https://chromium-review.googlesource.com/574025
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46704}

If the incremental marker discovers more marking work and the concurrent
marking tasks have already exited, then new concurrent marking tasks
are scheduled to help the main thread marker.

BUG=chromium:694255

Change-Id: I559af62790e6034b23a412d3308ba8b6ae3d27c9
Reviewed-on: https://chromium-review.googlesource.com/574170Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46703}