The twodigit_t code path emitted a library call rather than
a hardware "div" instruction. This is because compilers are
playing it safe: "div" can overflow when the divisor is too
small. Our algorithm carefully avoids this though, so using
the hardware "div" instruction is safe.

This speeds up a microbenchmark by almost 50%.

Bug: v8:6791
Change-Id: I35a73f8acdaca24f18327fbdaf7f53c4fd450c40
Reviewed-on: https://chromium-review.googlesource.com/686002Reviewed-by: Ben Smith <binji@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48351}

The typical pattern for using BuildCCall was to create a stack-allocated array
of arguments, which was passed to BuildCCall. BuildCCall then would allocate
scratch space using WasmGraphBuilder::Buffer and copy the arguments into the
scratch space. This copy is unnecessary and also the use of Buffer can lead to
silently overwriting scratch space that may be used higher up the stack.

Now BuildCCall takes all of the functions parameters as arguments and stores
this directly in a stack-allocated buffer, avoiding the use of Buffer at all and
all its associated pitfalls.

Change-Id: Ia0de9a90350d7fcbbb1b05d28e735d790a5f9143
Reviewed-on: https://chromium-review.googlesource.com/701638Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Eric Holk <eholk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48350}

This reverts commit f3c8da56.

Reason for revert: GC stress failures
https://build.chromium.org/p/client.v8/builders/V8%20Linux64%20GC%20Stress%20-%20custom%20snapshot/builds/15396

Original change's description:
> [heap] Use weak cell in normalized map cache.
> 
> This replaces ad-hoc weakness in normalized map cache with weak cell.
> 
> Bug: chromium:694255
> Change-Id: I6a12301b2176fe3723b56178a65582cfb412f7d2
> Reviewed-on: https://chromium-review.googlesource.com/704834
> Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#48344}

TBR=ulan@chromium.org,mlippautz@chromium.org

Change-Id: I0b2d39a1dcff6416998ab36506ee950220c87e89
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:694255
Reviewed-on: https://chromium-review.googlesource.com/705194Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48349}

Make calls like

  new Array(n)
  new A(n)

(where A is a subclass of Array) inlinable into TurboFan. We do this by
speculatively checking that n is an unsigned integer that is not greater
than JSArray::kInitialMaxFastElementArray, and then lowering the backing
store allocation to a builtin call. The speculative optimization is
either protected by the AllocationSite for the Array constructor
invocation (if we have one), or by a newly introduced global protector
cell that is used for Array constructor invocations that don't have an
AllocationSite, i.e. the ones from Array#map, Array#filter, or from
subclasses of Array.

Next step will be to implement the backing store allocations inline in
TurboFan, but that requires Loop support in the GraphAssembler, so it's
done as a separate CL. This should further boost the performance.

This boosts the ARES6 ML benchmark by up to 8% on the steady state,
and also improves monomorphic Array#map calls by around 20-25% on the
initial setup.

Bug: v8:6399
Tbr: ulan@chromium.org
Change-Id: I7c8bdecf7c814ce52db6ee3051c3206a4f7d4bb6
Reviewed-on: https://chromium-review.googlesource.com/704639
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48348}

Also delete duplicated code

Bug: v8:6404
Change-Id: I7f24d99573a854254aa0fd332fe5c947f93e0552
Reviewed-on: https://chromium-review.googlesource.com/704223Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48347}

This brings V8's behavior in line with both the spec and with
other engines.

This also fixes the (now-incorrect) DCHECK in BytecodeGenerator relating
to the delete operator's application to a VariableProxy.

Bug: v8:6697, v8:6721
Change-Id: I413c02af235b0bb652eb4c5d5c971e2cf80e0906
Reviewed-on: https://chromium-review.googlesource.com/703894Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Caitlin Potter <caitp@igalia.com>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Commit-Queue: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48346}

Also remove vogelheim (no longer on the team) for clarity.

Change-Id: Ida6d058252f17b71bb158308657ae2d18b52c2b2
Reviewed-on: https://chromium-review.googlesource.com/703161Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Reviewed-by: Daniel Ehrenberg <littledan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48345}

This replaces ad-hoc weakness in normalized map cache with weak cell.

Bug: chromium:694255
Change-Id: I6a12301b2176fe3723b56178a65582cfb412f7d2
Reviewed-on: https://chromium-review.googlesource.com/704834
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48344}

Bug: 
Change-Id: I2bebb92d2f5ed245bd7b20ee3ed1c6804605f837
Reviewed-on: https://chromium-review.googlesource.com/704644
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48343}

Bug: 
Change-Id: I780c83686b741e4d63a49ccb119a920c817d5a0a
Reviewed-on: https://chromium-review.googlesource.com/704718Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48342}

R=clemensh@chromium.org
TEST=mjsunit/regress/regress-crbug-772056
BUG=chromium:772056

Change-Id: I199262aa128ab395382520b1439ecc60ed141d4a
Reviewed-on: https://chromium-review.googlesource.com/704582Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48341}

NOTRY=true

Bug: chromium:772010
Change-Id: I510121accd739f1b8239720154d45846e83b3662
Reviewed-on: https://chromium-review.googlesource.com/704818Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48340}

Bug: 
Change-Id: I6b853f9462793c14aca3cc45c735ddcef6ed6155
Reviewed-on: https://chromium-review.googlesource.com/704637
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48339}

Bug: chromium:771966
Change-Id: I146b279c4713b7dd716c6d55ca5e6c6e23a3ad7e
Reviewed-on: https://chromium-review.googlesource.com/704740Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48338}

Bug: v8:6873
Change-Id: I1f544065dfec406bf3e4f16df38e80a1b1f7a173
Reviewed-on: https://chromium-review.googlesource.com/702281Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48337}

Bug: chromium:772190, v8:6819, v8:6820, v8:6831
Change-Id: Ied2dc954ff7575043988087d96782cfbb99e9ec8
Reviewed-on: https://chromium-review.googlesource.com/704578Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48336}

Avoid splitting functionality in two interface calls and passing around
a void* between them.

R=kschimpf@chromium.org

Change-Id: I0e12ff0295852ce5c36f7c3fb3b2c51dc0f2677e
Reviewed-on: https://chromium-review.googlesource.com/702484Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48335}

Currently, the transition elements kind operation invalidates the
elements of all other arrays. In particular, if we loop over matrix 
elements using two nested loops, and do possibly transitioning access 
a[i][j] in every iteration, we invalidate the load elimination state 
for the array 'a' because a[i][j] might transition elements kind 
for the 'a[i]' array. As a result, the 'a[i]' access cannot be 
hoisted from the inner loop.

With this CL, we figure out that transitioning 'a[i]' cannot affect 'a'
because we know that 'a' does not have the transition's source map.

In the micro-benchmark below, the time for summing up the elements of
100x100 matrix improves by factor of 1.7 (from ~340ms to ~190ms).

function matrixSum(a) {
  let s = 0;
  let rowCount = a.length;
  let columnCount = a[0].length;
  for (let i = 0; i < rowCount; i++) {
    for (let j = 0; j < columnCount ; j++) {
      s += a[i][j];
    }
  }
  return s;
}

// Setup the matrices:
// Smi elements.
var ma = [[1, 2], [3, 4]];
// Holey double elements.
var b = Array(100);
for (let i = 0; i < 100; i++) b[i] = 1.1;
var mb = [];
for (let i = 0; i < 100; i++) mb[i] = b;

// Warmup.
matrixSum(mb);
matrixSum(mb);
matrixSum(ma);
matrixSum(mb);
matrixSum(ma);

%OptimizeFunctionOnNextCall(matrixSum);

function runner(m) {
  let s = 0;
  for (let i = 0; i < 1e4; i++) {
    s += matrixSum(m);
  }
  return s;
}
// Make sure the runner does not know the elements kinds.
%NeverOptimizeFunction(runner);

// Measure.
console.time("Sum");
runner(mb);
console.timeEnd("Sum");


Bug: v8:6344
Change-Id: Ie0642d8693ed63116b1aaed7d2f261fcb64729fe
Reviewed-on: https://chromium-review.googlesource.com/704634
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48334}

R=clemensh@chromium.org

Bug: v8:6756
Change-Id: I3b25b89f3ead5c856be5c7ba3c7c236e595ce8de
Reviewed-on: https://chromium-review.googlesource.com/695524
Commit-Queue: Ben Titzer <titzer@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48333}

And other cleanups to reuse computed function names, and use
EmbeddedVector instead of ScopedVector (stack allocated instead of heap
allocated).

R=titzer@chromium.org

Change-Id: Id293946dc9aa574e7d185ff23b87068bca74549f
Reviewed-on: https://chromium-review.googlesource.com/690474Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48332}

Bug: v8:6399
Tbr: jarin@chromium.org
Change-Id: I98b4f2e3d9990fc38c7b5b2fac181e32ed4faa13
Reviewed-on: https://chromium-review.googlesource.com/704635Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48331}

Change-Id: I3ed30f539df5e9f02db8ca7934d2b68ad9437535
Reviewed-on: https://chromium-review.googlesource.com/694422
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48330}

Bug: chromium:771971, v8:6882
Change-Id: Id1a602306bc89a5f96e180f70d6f713015d2dbb6
Reviewed-on: https://chromium-review.googlesource.com/702834Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48329}

Bug: 
Change-Id: I1ca4246174e16dc3577f31a9e3a8333aadc17415
Reviewed-on: https://chromium-review.googlesource.com/702894Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48328}

Bug: 
Change-Id: I824f42cf6159f94204ee3e3c26a6af18e717b11e
Reviewed-on: https://chromium-review.googlesource.com/702874Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48327}

This repairs the performance regression on Octane/EarleyBoyer and
JetStream/EarleyBoyer benchmarks.

Bug: chromium:772268, v8:6367, v8:6278, v8:6344
Change-Id: Ibc144a35b37c5822f88712550d8db09386241341
Reviewed-on: https://chromium-review.googlesource.com/704574Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48326}

Array (subclass) constructor calls with 0 parameters are now properly
turned into inline allocations, also Array (subclass) constructor calls
with exactly one parameter, which is either known to not be a Number
or which is a known integer in the valid loop unrolling range.

Also refactor the general JSCreateArray lowering logic to properly
support Array subclasses, i.e. deal with inobject properties and
initial maps correctly.

This boosts performance of those cases significantly (and will allow
us to reduce the complexity of the Array constructor significantly
long-term). For example the simple case

  new Array("a", "b", "c", "d", "e", "f", "g")

is now around 10x faster than before.

Bug: v8:6399
Change-Id: I70661971398524ee0c6a349ee559b98a962a6266
Reviewed-on: https://chromium-review.googlesource.com/703134
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48325}

Fix disassembly of atomic operations for the inspector.

BUG=v8:6842,v8:6532

Change-Id: I3701b55c28b10561d1726e2c0b9fe2e1b2c76b8e
Reviewed-on: https://chromium-review.googlesource.com/703468
Commit-Queue: Brad Nelson <bradnelson@chromium.org>
Reviewed-by: Brad Nelson <bradnelson@chromium.org>
Reviewed-by: Ben Smith <binji@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48324}

Power-of-two radixes were supported already; this adds all others
(with 2 <= radix <= 36).

Bonus: fix digit_div fallback path for divisors with no leading zeros.

Bug: v8:6791
Change-Id: Id472667f057ad13338e0d8257a899490490e6f8f
Reviewed-on: https://chromium-review.googlesource.com/693316
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Daniel Ehrenberg <littledan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48323}

This adds a new simd lowering execution mode for
simd and re-enables the lowering tests

R=titzer@chromium.org,gdeepti@chromium.org,bbudge@chromium.org,mtrofin@chromium.org
BUG=v8:6020

Change-Id: Ice6b7ff2f5973804d379c88241d49b811429a965
Reviewed-on: https://chromium-review.googlesource.com/698928
Commit-Queue: Aseem Garg <aseemgarg@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48322}

BUG=chromium:760649

Change-Id: I13f3ad28ce3870ef57aa53eef684727656dcdff2
Reviewed-on: https://chromium-review.googlesource.com/701264
Commit-Queue: Alexei Filippov <alph@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48321}

The code used to rely on all such loops having a block scope around
them, but that is no longer the case for loops whose loop variables
are VAR-declared.

This patch introduces a new DeclarationDescriptor::Kind for such
variables, and sets it during parsing, allowing the variable
declaration code to note them as assigned appropriately.

Bug: chromium:768158
Change-Id: I0cd60e8c8c735681be9dbb9344a93156af09c952
Reviewed-on: https://chromium-review.googlesource.com/701624Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48320}

This allows us to remove the loop while calculating the hash value and
just use the HashMask as the mask for ComputeIntegerHash. This
previously overflowed on 32-bit systems failing the Smi::IsValid
check.

Bug: v8:6404
Change-Id: I84610a7592fa9d7ce4fa5cef7903bd50b8e8a4df
Reviewed-on: https://chromium-review.googlesource.com/702675Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48319}

Bug: v8:6644
Change-Id: I35c5a5095d0e154b4df0b6903e510587e869a2d4
Reviewed-on: https://chromium-review.googlesource.com/686822Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Georgia Kouveli <georgia.kouveli@arm.com>
Cr-Commit-Position: refs/heads/master@{#48318}

R=ahaas@chromium.org, ochang@chromium.org

Bug: Chromium:539572
Change-Id: I9e94a03c9173d0a17cb1a18dc8740972ff794368
Reviewed-on: https://chromium-review.googlesource.com/701601
Commit-Queue: Max Moroz <mmoroz@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48317}

Bug: chromium:771966
Change-Id: Iac5ee55c0d31de477f21f091f4be015a1ca8d00c
Reviewed-on: https://chromium-review.googlesource.com/702382Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48316}

The default component for src/ was Blink>JavaScript>Runtime
before. Unfortunately this is only partly true and tools
that use the information in the OWNERS file often misassign
issues because of it.

R=machenbach@chromium.org
NOTRY=true

Change-Id: I81457da1394a410fd494702f206af69857109c1c
Reviewed-on: https://chromium-review.googlesource.com/701758Reviewed-by: Michael Hablich <hablich@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
Commit-Queue: Michael Hablich <hablich@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48315}

At the moment we check only in the module-decoder if the sections in a
module appear at most once. The code section, however, we process
already before this check. With this CL we check that there is at most
one code section before we start processing it.

R=clemensh@chromium.org
TEST=WasmStreamingDecoderTest.TwoCodeSections

Bug: chromium:771916
Change-Id: Icc79d5a87ab39f450a35c688f74ea5e67cae4b3c
Reviewed-on: https://chromium-review.googlesource.com/702379Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48314}

This makes the test robust for stress GC flags.

Bug: 
Change-Id: Ica65987f0ee09fbdb4aab233dea4c51db5b19459
Reviewed-on: https://chromium-review.googlesource.com/702436Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48313}

If sweeping is not making progress and there are many young generation
GCs happening, then this can lead to accumulation of memory chunks in
the unmapper queue.

Bug: chromium:771966
Change-Id: Ief73ada0d17198a80b668850c6d2e7ea413113e7
Reviewed-on: https://chromium-review.googlesource.com/702479Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48312}