This eliminates the AstValue class, effectively moving its
implementation into the Literal AstNode. This should cause
no difference in behavior, but it does signal some shifts
in the underlying system. Biggest changes include:
- Reduction in AST memory usage
- No duplicate HeapNumbers in Ignition constant pools
- Non-String values are allocated either at constant pool
creation time (or at boilerplate creation time for literals),
rather than at AstValueFactory::Internalize() time.
There are a variety of test-only/debug-only changes due to these
switches as well.
Bug: v8:6984
Change-Id: I5f178040ce2796d4e7370c24d1063419e1c843a1
Reviewed-on: https://chromium-review.googlesource.com/731111
Commit-Queue: Adam Klein <adamk@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49013}
This removes all but one caller of Literal::raw_value(), thus
hiding AstValue from the rest of the codebase. This is in
preparation to move much of AstValue's implementation up
into Literal itself, thus avoiding the overhead of the
underling ZoneObjects and allowing us to remove complexity
such as the cache of Smi-valued AstValues.
Bug: v8:6984
Change-Id: I1b90aa64b9d26db36ef486afe73cda4473ef866e
Reviewed-on: https://chromium-review.googlesource.com/731109
Reviewed-by: Marja Hölttä <marja@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48884}
This adds a new InstanceOfIC where the TestInstanceOf bytecode collects
constant feedback about the right-hand side of instanceof operators,
including both JSFunction and JSBoundFunction instances. TurboFan then
uses the feedback to optimize instanceof in places where the right-hand
side is not a known constant (known to TurboFan).
This addresses the odd performance cliff that we see with instanceof in
functions with multiple closures. It was discovered as one of the main
bottlenecks on the uglify-es test in the web-tooling-benchmark. The
uglify-es test (run in separation) is ~18% faster with this change.
On the micro-benchmark in the tracking bug we go from
instanceofSingleClosure_Const: 69 ms.
instanceofSingleClosure_Class: 246 ms.
instanceofMultiClosure: 246 ms.
instanceofParameter: 246 ms.
to
instanceofSingleClosure_Const: 70 ms.
instanceofSingleClosure_Class: 75 ms.
instanceofMultiClosure: 76 ms.
instanceofParameter: 73 ms.
boosting performance by roughly 3.6x and thus effectively removing the
performance cliff around instanceof.
Bug: v8:6936, v8:6971
Change-Id: Ib88dbb9eaef9cafa4a0e260fbbde73427a54046e
Reviewed-on: https://chromium-review.googlesource.com/730686
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48820}
Moves the feedback vector slot allocation out of ast-numbering and into
bytecode generation directly. This has a couple of benifits, including reduced
AST size, avoid code duplication and reduced feedback vector sizes in many cases
due to only allocating slots when needed. Also removes AstProperties since
this is no longer needed.
AstNumbering is now only used to allocate suspend ids for generators.
BUG=v8:6921
Change-Id: I103e8593c94ef5b2e56c34ef4f77bd6e7d64796f
Reviewed-on: https://chromium-review.googlesource.com/722959
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48757}
This introduces a ToNumeric conversion to the runtime and interpreter.
ToNumeric behaves like ToNumber, except that it also lets BigInts pass.
Bug: v8:6791
Change-Id: Idf9d0b5d283638459fe5893de41cc120356247a7
Reviewed-on: https://chromium-review.googlesource.com/707013
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48440}
Tagged templates were previously desugared during parsing using some
combination of runtime support written in JavaScript and C++, which
prevented some optimizations from happening, namely the constant folding
of the template object in TurboFan optimized code. This CL adds a new
bytecode GetTemplateObject (with a corresponding GetTemplateObject AST
node), which represents the abstract operation in the ES6 specification
and allows TurboFan to simply constant-fold template objects at compile
time (which is explicitly supported by the specification).
This also pays down some technical debt by removing the template.js
runtime support and therefore should reduce the size of the native
context (snapshot) a bit.
With this change in-place the ES6 version microbenchmark in the
referenced tracking bug is now faster than the transpiled Babel
code, it goes from
templateStringTagES5: 4552 ms.
templateStringTagES6: 14185 ms.
templateStringTagBabel: 7626 ms.
to
templateStringTagES5: 4515 ms.
templateStringTagES6: 7491 ms.
templateStringTagBabel: 7639 ms.
which corresponds to a solid 45% reduction in execution time. With some
further optimizations the ES6 version should be able to outperform the
ES5 version. This micro-benchmark should be fairly representative of the
six-speed-templatestringtag-es6 benchmark, and as such that benchmark
should also improve by around 50%.
Bug: v8:6819,v8:6820
Tbr: mlippautz@chromium.org
Change-Id: I821085e3794717fc7f52b5c306fcb93ba03345dc
Reviewed-on: https://chromium-review.googlesource.com/677462
Reviewed-by: Mythri Alle <mythria@chromium.org>
Reviewed-by: Caitlin Potter <caitp@igalia.com>
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48126}
This continues to move the "desugaring" of unary operators further
down the pipeline, in this case into the bytecode handlers for new
bytecodes `Negate` and `BitwiseNot` and the corresponding TF code
in BytecodeGraphBuilder.
Bug: v8:6971
Tbr: yangguo@chromium.org
Change-Id: If6b5d6b239a09ef8b4dbde49321614503c0f5beb
Reviewed-on: https://chromium-review.googlesource.com/661146
Commit-Queue: Adam Klein <adamk@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47980}
As part of that change, make ToNumber return in the accumulator.
Bug: v8:6791
Change-Id: I8ce0f4fbc7ad8ee7fb4a32a8a499394395010750
Reviewed-on: https://chromium-review.googlesource.com/658082
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47976}
The advantage of an explicit Abort that the interpreter and the compiler know
that aborting cannot continue or throw or deopt. As a result we generate less
code and we do not confuse the compiler if the environment is not set up for
throwing (as in the generator dispatch that fails validation in
crbug.com/762057).
Bug: chromium:762057
Change-Id: I3e88f78be32f31ac49b1845595255f802c405ed7
Reviewed-on: https://chromium-review.googlesource.com/657025
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47922}
JavaScript is a dynamically typed language. But most code is
written with fixed types in mind. When debugging JavaScript,
it is helpful to know the types of variables and parameters
at runtime. It is often hard to infer types for complex code.
Type profiling provides this information at runtime.
Node.js uses the inspector protocol. This CL allows Node.js users
to access and analyse type profile for via Node modules or the
in-procress api. Type Profile helps developers to analyze
their code for correctness and performance.
Design doc: https://docs.google.com/a/google.com/document/d/1O1uepXZXBI6IwiawTrYC3ohhiNgzkyTdjn3R8ysbYgk/edit?usp=sharing
Add `takeTypeProfile` to the inspector protocol. It returns a list
of TypeProfileForScripts, which in turn contains the type profile for
each function. We can use TypeProfile data to annotate JavaScript code.
Sample script with data from TypeProfile:
function f(/*Object, number, undefined*/a,
/*Array, number, null*/b,
/*boolean, Object, symbol*/c) {
return 'bye';
/*string*/};
f({}, [], true);
f(3, 2.3, {a: 42});
f(undefined, null, Symbol('hello'));/*string*/
Bug: v8:5933
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: I626bfb886b752f90b9c86cc6953601558b18b60d
Reviewed-on: https://chromium-review.googlesource.com/508588
Commit-Queue: Franziska Hinkelmann <franzih@chromium.org>
Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47920}
This CL adds support to optimize for..in in fast enum-cache mode to the
same degree that it was optimized in Crankshaft, without adding the same
deoptimization loop that Crankshaft had with missing enum cache indices.
That means code like
for (var k in o) {
var v = o[k];
// ...
}
and code like
for (var k in o) {
if (Object.prototype.hasOwnProperty.call(o, k)) {
var v = o[k];
// ...
}
}
which follows the https://eslint.org/docs/rules/guard-for-in linter
rule, can now utilize the enum cache indices if o has only fast
properties on the receiver, which speeds up the access o[k]
significantly and reduces the pollution of the global megamorphic
stub cache.
For example the micro-benchmark in the tracking bug v8:6702 now runs
faster than ever before:
forIn: 1516 ms.
forInHasOwnProperty: 1674 ms.
forInHasOwnPropertySafe: 1595 ms.
forInSum: 2051 ms.
forInSumSafe: 2215 ms.
Compared to numbers from V8 5.8 which is the last version running with
Crankshaft
forIn: 1641 ms.
forInHasOwnProperty: 1719 ms.
forInHasOwnPropertySafe: 1802 ms.
forInSum: 2226 ms.
forInSumSafe: 2409 ms.
and V8 6.0 which is the current stable version with TurboFan:
forIn: 1713 ms.
forInHasOwnProperty: 5417 ms.
forInHasOwnPropertySafe: 5324 ms.
forInSum: 7556 ms.
forInSumSafe: 11067 ms.
It also improves the throughput on the string-fasta benchmark by
around 7-10%, and there seems to be a ~5% improvement on the
Speedometer/React benchmark locally.
For this to work, the ForInPrepare bytecode was split into
ForInEnumerate and ForInPrepare, which is very similar to how it was
handled in Fullcodegen initially. In TurboFan we introduce a new
operator LoadFieldByIndex that does the dynamic property load.
This also removes the CheckMapValue operator again in favor of
just using LoadField, ReferenceEqual and CheckIf, which work
automatically with the EscapeAnalysis and the
BranchConditionElimination.
Bug: v8:6702
Change-Id: I91235413eea478ba77ace7bd14bb2f62e155dd9a
Reviewed-on: https://chromium-review.googlesource.com/645949
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47768}
The quite common empty object literal doesn't need an AllocationSite
since it starts off with the general ElementsKind. By using a separate
bytecode we can directly instantiate the empty object without jumping
to the runtime first.
Note: this experimentally disables pretenuring for empty object
literals. Depending on the outcome of our benchmarks pretenuring
will be enabled again or fully removed for empty object literals.
Bug: v8:6211
Change-Id: I2fee81cbefc70865fc436dbd3bc5fc8de04db91c
Reviewed-on: https://chromium-review.googlesource.com/577555
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47467}
Remove need for shuffling of accumulator and operand registers when
suspending a generator
BUG=v8:6351
TBR=bmeurer@chromium.org
Change-Id: I372509adc03b9781716412b809639554fe16e372
Reviewed-on: https://chromium-review.googlesource.com/578377
Commit-Queue: Caitlin Potter <caitp@igalia.com>
Reviewed-by: Caitlin Potter <caitp@igalia.com>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46883}
Empty Array literals are amongst the most commonly used literal types on our
top25 page list. Using a custom bytecode we can drop the boilerplate for empty
Array literals alltogether. However, we still need a proper AllocationSite to
track ElementsKind transitions.
Bug: v8:6211, chromium:746935
Change-Id: I891eaa778e4e81e138e483a65f04ae00ae30bd28
Reviewed-on: https://chromium-review.googlesource.com/580932
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46875}
Properly hook up the (existing) IC slots for the CallWithSpread and
ConstructWithSpread bytecodes, and change the interpreter to collect
feedback (call counts and regular target function feedback) for those.
There's no integration with the Array constructor yet, since that
requires some yak shaving to thread through the AllocationSite to the
Array constructor stub. Once we have a solution for that, we can also
remove the current code duplication in the Call/Construct IC logic.
Also properly hook up the newly available feedback in TurboFan. This
will fix not only the missing target feedback, but more importantly
the tear-up decisions for optimization are correct now in the presence
of spread calls, and even more importantly the inlining heurstic has
proper call frequencies for those.
Some follow-up changes will be necessary to make sure we use the
feedback even for corner cases that aren't handled properly yet. Also
we should consider collecting feedback about the map of the spread
at some point to be able to always inline the spread calls.
Bug: v8:6399, v8:6527, v8:6630
Change-Id: I818dbcb411fd3951d8e9d31f5d7e794f8d60fa00
Reviewed-on: https://chromium-review.googlesource.com/582647
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46832}
This reverts commit 4851745fe3.
Reason for revert: Top crasher on Canary, see https://crbug.com/746935
Original change's description:
> [literals] Introduce CreateEmptyArrayLiteral Bytecode
>
> Empty Array literals are amongst the most commonly used literal types on our
> top25 page list. Using a custom bytecode we can drop the boilerplate for empty
> Array literals alltogether. However, we still need a proper AllocationSite to
> track ElementsKind transitions.
>
> Bug: v8:6211
> Change-Id: Id5dbdac0ea8e24dd474e679c902c6e4a2957af1d
> Reviewed-on: https://chromium-review.googlesource.com/567079
> Commit-Queue: Camillo Bruni <cbruni@chromium.org>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#46752}
TBR=rmcilroy@chromium.org,mstarzinger@chromium.org,cbruni@chromium.org,ishell@chromium.org,rmcilroy@google.com
Bug: v8:6211, chromium:746935
Change-Id: Ibf19a923688c071d03bad8661a10e08f8414db56
Reviewed-on: https://chromium-review.googlesource.com/580193
Commit-Queue: Adam Klein <adamk@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46804}
There remained a few of regressions and we didn't see any significant
improvement in the real world with this turned on. This CL reverts all the
StringConcat bytecode work which landed.
BUG=v8:6243
Change-Id: I832eb72e880ad41411dbec8fe29f71ef0f2025c8
Reviewed-on: https://chromium-review.googlesource.com/575130
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46769}
Empty Array literals are amongst the most commonly used literal types on our
top25 page list. Using a custom bytecode we can drop the boilerplate for empty
Array literals alltogether. However, we still need a proper AllocationSite to
track ElementsKind transitions.
Bug: v8:6211
Change-Id: Id5dbdac0ea8e24dd474e679c902c6e4a2957af1d
Reviewed-on: https://chromium-review.googlesource.com/567079
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46752}
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/543161
Reviewed-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}
SuspendFlags was originally used by the suspend operation to determine
which field to record the bytecode offset of a suspended generator, and
the value the generator was resumed with. For async generators, await
operations would use a separate field, in order to preserve the previous
yield input value. This was important to ensure `function.sent`
continued to function correctly.
As function.sent is being retired, this allows the removal of support
for that. Given that this was the only real need for SuspendFlags in the
first place (with other uses tacked on as a hack), this involves several
other changes as well:
- Modification of MacroAssembler AssertGeneratorObject. No longer
accepts a SuspendFlags parameter to determine which type of check to
perform.
- Removal of `flags` operand from SuspendGenerator bytecode, and the
GeneratorStore js-operator.
- Removal of `flags` parameter from ResumeGeneratorTrampoline builtins.
- Removal of Runtime functions, interpreter intrinsics and
AccessBuilders associated with the [[await_input_or_debug_pos]] field
in JSAsyncGeneratorObject, as this field no longer exists.
- Addition of a new `Yield` AST node (subclass of Suspend) in order to
prevent the need for the other SuspendFlag values.
BUG=v8:5855
TBR=bmeurer@chromium.org
Change-Id: Iff2881e4742497fe5b774915e988c3d9d8fbe487
Reviewed-on: https://chromium-review.googlesource.com/570485
Commit-Queue: Caitlin Potter <caitp@igalia.com>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46683}
The tail call implementation is hidden behind the --harmony-tailcalls
flag, which is off-by-default (and has been unstaged since February).
It is known to be broken in a variety of cases, including clusterfuzz
security issues (see sample Chromium issues below). To avoid letting
the implementation bitrot further on trunk, this patch removes it.
Bug: v8:4698, chromium:636914, chromium:724746
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng;master.tryserver.v8:v8_linux_noi18n_rel_ng
Change-Id: I9cb547101456a582374fdf7b1a3f044a9ef33e5c
Reviewed-on: https://chromium-review.googlesource.com/569069
Commit-Queue: Adam Klein <adamk@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46651}
Move bytecode array writing logic into the array builder, allowing us to
remove the bytecode array writer and bytecode node, and convert runtime
operand writing to compile-time bytecode operand writing using the
information statically known at compile time.
Bug: v8:6474
Change-Id: I210cd9897fd41293745614e4a253c7c251dfffc9
Reviewed-on: https://chromium-review.googlesource.com/533055
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46183}
In edge cases such as the following, sloppy-mode block-scoped function
hoisting is expected to occur:
eval(`
with({a: 1}) {
function a() {}
}
`)
In this case, there should be the equivalent of a var declaration
outside of the eval, which gets set to the value of the local function
a when the body of the with is executed.
Previously, the way that var declarations are hoisted out of eval
meant that the assignment to that var was an ordinary DYNAMIC_GLOBAL
assignment. However, such a lookup mode meant that the object in the
with scope received the assignment!
This patch fixes that error by marking the assignments produced by
the sloppy mode block scoped function hoisting desugaring so as to
generate a different runtime call which skips with scopes.
Bug: chromium:720247, v8:5135
Change-Id: Ie36322ddc9ca848bf680163e8c016f50d4597748
Reviewed-on: https://chromium-review.googlesource.com/529230
Commit-Queue: Daniel Ehrenberg <littledan@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46116}
This CL implements general infrastructure for block coverage together with
initial support for if-statements.
Coverage output can be generated in lcov format by d8 as follows:
$ d8 --block-coverage --lcov=$(echo ~/simple-if.lcov) ~/simple-if.js
$ genhtml ~/simple-if.lcov -o ~/simple-if
$ chrome ~/simple-if/index.html
A high level overview of the implementation follows:
The parser now collects source ranges unconditionally for relevant AST nodes.
Memory overhead is very low and this seemed like the cleanest and simplest
alternative.
Bytecode generation uses these ranges to allocate coverage slots and insert
IncBlockCounter instructions (e.g. at the beginning of then- and else blocks
for if-statements). The slot-range mapping is generated here and passed on
through CompilationInfo, and is later accessible through the
SharedFunctionInfo.
The IncBlockCounter bytecode fetches the slot-range mapping (called
CoverageInfo) from the shared function info and simply increments the counter.
We don't collect native-context-specific counts as they are irrelevant to our
use-cases.
Coverage information is finally generated on-demand through Coverage::Collect.
The only current consumer is a d8 front-end with lcov-style output, but the
short-term goal is to expose this through the inspector protocol.
BUG=v8:6000
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_chromium_rel_ng
Review-Url: https://codereview.chromium.org/2882973002
Cr-Commit-Position: refs/heads/master@{#45737}
Introduces ThrowReferenceErrorIfHole / ThrowSuperNotCalledIfHole
/ ThrowSuperAlreadyCalledIfNotHole bytecodes to handle hole checks.
In the bytecode-graph builder they are handled by introducing a deopt point
instead of adding explicit control flow. JumpIfNotHole / JumpIfNotHoleConstant
bytecodes are removed since they are no longer required.
Bug: v8:4280, v8:6383
Change-Id: I58b70c556b0ffa30e41a0cd44016874c3e9c5fe1
Reviewed-on: https://chromium-review.googlesource.com/509613
Commit-Queue: Mythri Alle <mythria@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45720}
Unfortunately, even for an empty generator, we still use 8 register for various things (try-finally, copies of generator object, parser-introduced temporaries). I will try to get rid of these in separate CLs.
Changes:
- SuspendGenerator bytecode now takes register list to save.
- ResumeGenerator was split into two bytecodes:
* Resume generator reads the state out and marks the generator as
'executing'.
* RestoreGeneratorRegisters reloads the registers from
the generator.
+ this required adding support for output register list.
- Introduced generator_object_ register in the bytecode generator.
* in subsequent CLs, I will make better use of it, the goal is
to get rid if the .generator_object local variable.
- Taught register optimizer to flush unassigned registers.
BUG=v8:6379
Review-Url: https://codereview.chromium.org/2894293003
Cr-Commit-Position: refs/heads/master@{#45675}
Rather than trying to pre-calculate the number of contexts required during
scope analysis, instead just allocate context registers in the register
allocator. This reduces frame size a bit due to reusing of registers when
the context isn't pushed.
BUG=v8:6322, chromium:716265
Change-Id: I145e38fcb3797a3b86c91e90ea9326a6e55b9b89
Reviewed-on: https://chromium-review.googlesource.com/514087
Reviewed-by: Marja Hölttä <marja@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45522}
Special cases addition expressions where one of the sides is known to be a
string to enable chains of string additions to be transformed into a series
of ToPrimitiveToString operations followed by a single string concatenation
at the end of the chain of additions. This should avoid creating temporary
strings for each of the string additions (in essence this is an automated
string builder).
BUG=v8:6243
Change-Id: I44977d6dad00ee906f251c4bd9cab27e160c09d1
Reviewed-on: https://chromium-review.googlesource.com/493966
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45453}
Introduce a new SwitchSmiTable bytecode for generators, which does a
table lookup for the accumulator value in a jump table stored in the
constant array pool. This removes the if-else chains at resumable
function/loop headers.
As a drive-by, add a scoped environment saving struct to the bytecode
graph builder.
Bug: v8:6351
Bug: v8:6366
Change-Id: I63be15a8b599d6684c7df19dedb8860562678fb0
Reviewed-on: https://chromium-review.googlesource.com/500271
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45314}
BytecodeRegisterOptimizer had special handling for the case when parameters
is 0. This is not possible from valid javascript. It exists because some
tests do not take this into account. Fixed tests and removed the special
handling.
Also removed a TODO, which is already done here:
https://codereview.chromium.org/2227203002/
Bug: v8:4280,v8:6325
Change-Id: Idc17af12ad9292c13a6677aa4c8b88d21f4adf81
Reviewed-on: https://chromium-review.googlesource.com/490308
Commit-Queue: Mythri Alle <mythria@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45036}
Adds a collection of call bytecodes which have an implicit undefined
receiver argument, for cases such as global calls where we know that the
receiver has to be undefined. This way we can skip an LdaUndefined,
decrease bytecode register pressure, and set a more accurate
ConvertReceiverMode on the interpreter and TurboFan call.
As a side effect, the "normal" Call bytecode now becomes a rare case
(only with calls and super property calls), so we get rid of its 0-2
argument special cases and modify CallProperty[N] to use the
NotNullOrUndefined ConvertReceiverMode.
Reland of https://chromium-review.googlesource.com/c/463287 after fixing
tests in https://codereview.chromium.org/2813873002.
Change-Id: I314d69c7643ceec6a5750ffdab60dad38dad09e5
Reviewed-on: https://chromium-review.googlesource.com/474752
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44582}
All the optimizations have now been moved to either the BytecodeGenerator
or the BytecodeArrayWriter/Builder.
BUG=v8:6194
Change-Id: Ie5c5d55e824c94ffb503af376c72bc64ad1f6f81
Reviewed-on: https://chromium-review.googlesource.com/469349
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44564}
This reverts commit 751e893591.
Reason for revert: Breaks layout tests:
https://build.chromium.org/p/client.v8.fyi/builders/V8-Blink%20Linux%2064/builds/14885
See:
https://github.com/v8/v8/wiki/Blink-layout-tests
Original change's description:
> [ignition] Add call bytecodes for undefined receiver
>
> Adds a collection of call bytecodes which have an implicit undefined
> receiver argument, for cases such as global calls where we know that the
> receiver has to be undefined. This way we can skip an LdaUndefined,
> decrease bytecode register pressure, and set a more accurate
> ConvertReceiverMode on the interpreter and TurboFan call.
>
> As a side effect, the "normal" Call bytecode now becomes a rare case
> (only with calls and super property calls), so we get rid of its 0-2
> argument special cases and modify CallProperty[N] to use the
> NotNullOrUndefined ConvertReceiverMode.
>
> Change-Id: I9374a32fefd66fc0251b5193bae7a6b7dc31eefc
> Reviewed-on: https://chromium-review.googlesource.com/463287
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#44530}
TBR=rmcilroy@chromium.org,mstarzinger@chromium.org,leszeks@chromium.org,v8-reviews@googlegroups.com,v8-mips-ports@googlegroups.com,v8-ppc-ports@googlegroups.com,v8-x87-ports@googlegroups.com,bmeurer@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
Change-Id: I7629dec609d0ec938ce7105d6c1c74884e5f9272
Reviewed-on: https://chromium-review.googlesource.com/474744
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44548}
Adds a collection of call bytecodes which have an implicit undefined
receiver argument, for cases such as global calls where we know that the
receiver has to be undefined. This way we can skip an LdaUndefined,
decrease bytecode register pressure, and set a more accurate
ConvertReceiverMode on the interpreter and TurboFan call.
As a side effect, the "normal" Call bytecode now becomes a rare case
(only with calls and super property calls), so we get rid of its 0-2
argument special cases and modify CallProperty[N] to use the
NotNullOrUndefined ConvertReceiverMode.
Change-Id: I9374a32fefd66fc0251b5193bae7a6b7dc31eefc
Reviewed-on: https://chromium-review.googlesource.com/463287
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44530}
This relands commit d3e9aade0f. The original CL was reverted speculatively but didn't cause the buildbot failure.
Original change's description:
> [Interpreter] Move BinaryOp Smi transformation into BytecodeGenerator.
>
> Perform the transformation to <BinaryOp>Smi for Binary ops which take Smi
> literals in the BytecodeGenerator. This enables us to perform the
> transformation for literals on either side for commutative operations, and
> Avoids having to do the check on every bytecode in the peephole optimizer.
>
> In the process, adds Smi bytecode variants for all binary operations, adding
> - MulSmi
> - DivSmi
> - ModSmi
> - BitwiseXorSmi
> - ShiftRightLogical
>
> BUG=v8:6194
>
> Change-Id: If1484252f5385c16957004b9cac8bfbb1f209219
> Reviewed-on: https://chromium-review.googlesource.com/466246
> Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#44477}
TBR=rmcilroy@chromium.org,machenbach@chromium.org,yangguo@chromium.org,mstarzinger@chromium.org,mythria@chromium.org,v8-reviews@googlegroups.com,ishell@chromium.org
# Not skipping CQ checks because original CL landed > 1 day ago.
BUG=v8:6194
Change-Id: I2ccaefa1ce58d3885f5c2648755985c06f25c1d8
Reviewed-on: https://chromium-review.googlesource.com/472746
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44511}
This reverts commit d3e9aade0f.
Reason for revert: Speculative for:
https://build.chromium.org/p/client.v8.ports/builders/V8%20Linux%20-%20arm64%20-%20sim%20-%20nosnap%20-%20debug/builds/4449
Bisect points to this CL.
Original change's description:
> [Interpreter] Move BinaryOp Smi transformation into BytecodeGenerator.
>
> Perform the transformation to <BinaryOp>Smi for Binary ops which take Smi
> literals in the BytecodeGenerator. This enables us to perform the
> transformation for literals on either side for commutative operations, and
> Avoids having to do the check on every bytecode in the peephole optimizer.
>
> In the process, adds Smi bytecode variants for all binary operations, adding
> - MulSmi
> - DivSmi
> - ModSmi
> - BitwiseXorSmi
> - ShiftRightLogical
>
> BUG=v8:6194
>
> Change-Id: If1484252f5385c16957004b9cac8bfbb1f209219
> Reviewed-on: https://chromium-review.googlesource.com/466246
> Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#44477}
TBR=rmcilroy@chromium.org,yangguo@chromium.org,mstarzinger@chromium.org,mythria@chromium.org,ishell@chromium.org,v8-reviews@googlegroups.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:6194
Change-Id: If57dbdbe40be77804bf437463b855d3167e2d473
Reviewed-on: https://chromium-review.googlesource.com/471308
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44488}
Perform the transformation to <BinaryOp>Smi for Binary ops which take Smi
literals in the BytecodeGenerator. This enables us to perform the
transformation for literals on either side for commutative operations, and
Avoids having to do the check on every bytecode in the peephole optimizer.
In the process, adds Smi bytecode variants for all binary operations, adding
- MulSmi
- DivSmi
- ModSmi
- BitwiseXorSmi
- ShiftRightLogical
BUG=v8:6194
Change-Id: If1484252f5385c16957004b9cac8bfbb1f209219
Reviewed-on: https://chromium-review.googlesource.com/466246
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44477}
Make Ignition collect BinaryOperationFeedback on ToNumber, using the
shared type feedback slot with the following Inc/Dec bytecode, and use
this feedback in TurboFan to turn the ToNumber(x) operation into a
SpeculativeNumberMultiply(x,1) with the feedback hint.
R=jarin@chromium.org, mstarzinger@chromium.org, rmcilroy@chromium.org
BUG=v8:6214,v8:5267
Review-Url: https://codereview.chromium.org/2804813003
Cr-Commit-Position: refs/heads/master@{#44440}
Move the ToBoolean elision in the BytecodeGenerator instead of the
peephole optimizer. Adds a TypeHint mechanism to the ExpressionResult
to enable passing of type hints through the ast visitor.
BUG=v8:6194
Change-Id: Ic55506ba11b213f7459250004d3f18cab04ee9b3
Reviewed-on: https://chromium-review.googlesource.com/467208
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44415}
Translates code of the form 'if (x === undefined)' into the JumpIfUndefined
bytecode, and similarly for comparisons with null. Also adds bytecodes for
JumpIfNotUndefined / Null.
Moves the peephole optimization for CompareUndefined out of the peephole
optimizer and into the BytecodeGenerator, having the side-effect of enabling
it for comparisons with undefined on both side of the compare operation.
BUG=v8:6107
Review-Url: https://codereview.chromium.org/2793923002
Cr-Commit-Position: refs/heads/master@{#44341}
The parameter indices are shifted by 1 in BytecodeArrayBuilder
because the receiver is variable at index 0 and not -1.
Split BytecodeArrayBuilder::Parameter(index) method into
Receiver() (same as Parameter(-1)) and
Parameter(index).
This way we avoid confusing (index+1) counting in BytecodeGenerator().
BUG=
Change-Id: Id87ec7c708cecfc3108011994f3177f483772bcc
Reviewed-on: https://chromium-review.googlesource.com/461904
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Franziska Hinkelmann <franzih@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44262}
- Introduce new struct AsyncGeneratorRequest, which holds
information pertinent to resuming execution of an
AsyncGenerator, such as the Promise associated with the async
generator request. It is intended to be used as a singly
linked list, and holds a pointer to the next item in te queue.
- Introduce JSAsyncGeneratorObject (subclass of
JSGeneratorObject), which includes several new internal fields
(`queue` which contains a singly linked list of
AsyncGeneratorRequest objects, and `await_input` which
contains the sent value from an Await expression (This is
necessary to prevent function.sent (used by yield*) from
having the sent value observably overwritten during
execution).
- Modify SuspendGenerator to accept a set of Flags, which
indicate whether the suspend is for a Yield or Await, and
whether it takes place on an async generator or ES6
generator.
- Introduce interpreter intrinsics and TF intrinsic lowering for
accessing the await input of an async generator
- Modify the JSGeneratorStore operator to understand whether or
not it's suspending for a normal yield, or an AsyncGenerator
Await. This ensures appropriate registers are stored.
- Add versions of ResumeGeneratorTrampoline which store the
input value in a different field depending on wether it's an
AsyncGenerator Await resume, or an ordinary resume. Also modifies
whether debug code will assert that the generator object is a
JSGeneratorObject or a JSAsyncGeneratorObject depending on the
resume type.
BUG=v8:5855
R=bmeurer@chromium.org, rmcilroy@chromium.org, jgruber@chromium.org,
littledan@chromium.org, neis@chromium.orgTBR=marja@chromium.org
Change-Id: I9d58df1d344465fc937fe7eed322424204497187
Reviewed-on: https://chromium-review.googlesource.com/446961
Commit-Queue: Caitlin Potter <caitp@igalia.com>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44240}
Some of the StrictEquality comparisons do not require feedback (for ex: in
try-finally, generators). This cl introduces StrictEqualityNoFeedback bytecode
to be used in such cases. With this change, we no longer have to check if the
type feedback slot is valid in compare bytecode handlers.
This is the first step in reworking the compare bytecode handler to avoid
duplicate checks when collecting feedback and when performing the operation.
BUG=v8:4280
Change-Id: Ia650fd43c0466b8625d3ce98c39ed1073ba42a6b
Reviewed-on: https://chromium-review.googlesource.com/455778
Commit-Queue: Mythri Alle <mythria@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44020}
Collect type information for JavaScript variables and display it
in Chrome DevTools.
Design Doc: https://docs.google.com/a/google.com/document/d/1O1uepXZXBI6IwiawTrYC3ohhiNgzkyTdjn3R8ysbYgk/edit?usp=sharing
When debugging JavaScript, it’s helpful to know the type of
a variable, parameter, and return values. JavaScript is
dynamically typed, and for complex
source code it’s often hard to infer types. With type profiling, we
can provide type information to JavaScript developers.
This CL is a proof of concept. It collects type profile for
assignments and simply prints the types to stdout.
The output looks something like this:
#my_var1
#Object
#number
#string
#number
#undefined
#string
#Object
#Object
We use an extra slot in the feedback vector of assignments to
carry the list of types for that assignment. The extra slot is
only added when the flag --type-profile is given.
Missing work:
* Collect data for parameters and return values (currently only assignments).
* Remove duplicates from the list of collected types and use a common base class.
* Add line numbers or source position instead of the variable name.
For now, has a test that compares the stdout of --type-profile in test/message. We
will remove this test when --type-profile is fully integrated in
the debugger protocol. Adding
the test in test/inspector does not work, because the inspector
test itself consists of JavaScript code that would convolute the
output and be non-deterministic under stress.
BUG=v8:5935
Review-Url: https://codereview.chromium.org/2707873002
Cr-Commit-Position: refs/heads/master@{#43866}
Reason for revert:
Still flaky
Original issue's description:
> Collect type profile for DevTools
>
> Collect type information for JavaScript variables and display it
> in Chrome DevTools.
> Design Doc: https://docs.google.com/a/google.com/document/d/1O1uepXZXBI6IwiawTrYC3ohhiNgzkyTdjn3R8ysbYgk/edit?usp=sharing
>
> When debugging JavaScript, it’s helpful to know the type of
> a variable, parameter, and return values. JavaScript is
> dynamically typed, and for complex
> source code it’s often hard to infer types. With type profiling, we
> can provide type information to JavaScript developers.
>
> This CL is a proof of concept. It collects type profile for
> assignments and simply prints the types to stdout.
>
> The output looks something like this:
>
> #my_var1
> #Object
> #number
> #string
> #number
> #undefined
> #string
> #Object
> #Object
>
>
> We use an extra slot in the feedback vector of assignments to
> carry the list of types for that assignment. The extra slot is
> only added when the flag --type-profile is given.
>
>
> Missing work:
> * Collect data for parameters and return values (currently only assignments).
> * Remove duplicates from the list of collected types and use a common base class.
> * Add line numbers or source position instead of the variable name.
>
>
>
> BUG=v8:5935
>
> Review-Url: https://codereview.chromium.org/2707873002
> Cr-Original-Original-Original-Commit-Position: refs/heads/master@{#43791}
> Committed: 0332bebde9
> Review-Url: https://codereview.chromium.org/2707873002
> Cr-Original-Original-Commit-Position: refs/heads/master@{#43804}
> Committed: 6cf880f4b8
> Review-Url: https://codereview.chromium.org/2707873002
> Cr-Original-Commit-Position: refs/heads/master@{#43846}
> Committed: 5c32287390
> Review-Url: https://codereview.chromium.org/2707873002
> Cr-Commit-Position: refs/heads/master@{#43849}
> Committed: 18c35e4958TBR=yangguo@chromium.org,mvstanton@chromium.org,rmcilroy@chromium.org,mstarzinger@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5935
Review-Url: https://codereview.chromium.org/2745413006
Cr-Commit-Position: refs/heads/master@{#43852}
Collect type information for JavaScript variables and display it
in Chrome DevTools.
Design Doc: https://docs.google.com/a/google.com/document/d/1O1uepXZXBI6IwiawTrYC3ohhiNgzkyTdjn3R8ysbYgk/edit?usp=sharing
When debugging JavaScript, it’s helpful to know the type of
a variable, parameter, and return values. JavaScript is
dynamically typed, and for complex
source code it’s often hard to infer types. With type profiling, we
can provide type information to JavaScript developers.
This CL is a proof of concept. It collects type profile for
assignments and simply prints the types to stdout.
The output looks something like this:
#my_var1
#Object
#number
#string
#number
#undefined
#string
#Object
#Object
We use an extra slot in the feedback vector of assignments to
carry the list of types for that assignment. The extra slot is
only added when the flag --type-profile is given.
Missing work:
* Collect data for parameters and return values (currently only assignments).
* Remove duplicates from the list of collected types and use a common base class.
* Add line numbers or source position instead of the variable name.
BUG=v8:5935
Review-Url: https://codereview.chromium.org/2707873002
Cr-Original-Original-Original-Commit-Position: refs/heads/master@{#43791}
Committed: 0332bebde9
Review-Url: https://codereview.chromium.org/2707873002
Cr-Original-Original-Commit-Position: refs/heads/master@{#43804}
Committed: 6cf880f4b8
Review-Url: https://codereview.chromium.org/2707873002
Cr-Original-Commit-Position: refs/heads/master@{#43846}
Committed: 5c32287390
Review-Url: https://codereview.chromium.org/2707873002
Cr-Commit-Position: refs/heads/master@{#43849}
