A continuation of the work in 59e4b751, this extracts logic around
memory reservation and allocations out of the Deserializer class.
Follow-up work is planned to create a specialized allocator for
builtin deserialization.
Bug: v8:6624
Change-Id: I7081cdc557ab8fb2571aadb816399e136ea2cdbb
Reviewed-on: https://chromium-review.googlesource.com/716036
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48634}
Port the baseline version of Reflect.has to the CodeStubAssembler and
reuse the existing logic for HasProperty (i.e. the HasProperty builtin).
Also inline the Reflect.has builtin into TurboFan, by adding a check
on the target in front of a use of the JSHasProperty operator.
Technically this additional check is not necessary, because the
JSHasProperty operator already throws if the target is not a JSReceiver,
but the exception message is confusing then.
This improves the performance of the micro-benchmark from
reflectHasPresent: 337 ms.
reflectHasAbsent: 472 ms.
to
reflectHasPresent: 121 ms.
reflectHasAbsent: 216 ms.
which is a nice 2.8x improvement in the best case. It also improves the
chai test on the web-tooling-benchmark by around 1-2%, which is roughly
the expected win (since Reflect.has overall accounts for around 3-4%).
Bug: v8:5996, v8:6936, v8:6937
Change-Id: I856183229677a71c19936f06f2a4fc7a794a9a4a
Reviewed-on: https://chromium-review.googlesource.com/720959
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48608}
This file was somehow inexplicably not moved when other parsing files were.
BUG=v8:6921
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: Iea92c61f83dbb5a8688c404ba87d35fa58e749b9
Reviewed-on: https://chromium-review.googlesource.com/718197
Commit-Queue: Marja Hölttä <marja@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48522}
This makes all inline allocation constructions go through the existing
{AllocationBuilder} helper class. It hence ensures there is a single
place for all sanity checking and and makes use-sites easier to read.
R=jarin@chromium.org
Change-Id: Ib5daf48acd93c631fccdfa095eda1afda7048115
Reviewed-on: https://chromium-review.googlesource.com/709056
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48502}
Sometimes, the embedder might want to merge a fix to an abandoned branch
or to a supported branch but the fix is not relevant to Chromium.
This adds a new version string that the embedder can set at compile time
and that will be appended to the official V8 version.
The separator must be provided in the string. For instance, to have a
full version string like "6.0.287.53-emb.1", the embedder must set
V8_EMBEDDER_STRING to "-emb.1".
Related Node.js issue: https://github.com/nodejs/node/pull/9754
BUG=v8:5740
R=machenbach@chromium.org
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: Ifa2d9bd213795e6d54886436f8c3787ac6162823
Reviewed-on: https://chromium-review.googlesource.com/690475
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Michaël Zasso <mic.besace@gmail.com>
Cr-Commit-Position: refs/heads/master@{#48301}
With --wasm-trace-memory, both compiled code and the interpreter will
output each memory load or store. This helps to debug miscompilations in
emscripten or in V8, like the referenced bug.
R=titzer@chromium.org
Bug: chromium:718858
Change-Id: I90704d164975b11c65677f86947ab102242d5153
Reviewed-on: https://chromium-review.googlesource.com/684316
Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48255}
There are only very few custom compiled IC handlers left that go in there, and for each compiled handler we only have 1 cache hit on top25; maximally saving 60ms over 33s. Additionally we'll migrate the remaining handlers to data-driven handlers anyway. Let's try to remove this code.
Bug:
Change-Id: Ib874cc498015046a3ff67c83ea8b10b3c4eb7d0f
Reviewed-on: https://chromium-review.googlesource.com/668409
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48201}
ZoneList still used List as a base class, so this CL merges the two
classes together. We also remove unused functions in List and ZoneList.
We keep the inline header but move it to src/zone/zone-list-inl.h. The
includes that use this header are still quite tangled, but we can fix
that later.
Bug: v8:6333
Cq-Include-Trybots: master.tryserver.v8:v8_linux_noi18n_rel_ng
Change-Id: Ia809813834b2328ff616623f8a843812a1eb42a7
Reviewed-on: https://chromium-review.googlesource.com/681658
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48200}
The members of HandleScopeImplementer are copied with memcpy when
the isolate is transferred to another thread. List contained some
primitives which allowed us to manually free the backing store, which
was needed in order to ensure that threads would not hold on to
old pointers and use them later. With std::vector, we can't do that.
Here we change the HandleScopeImplementer to instead use a custom
structure DetachableVector, which contains a std::vector but allows
manual detaching and freeing of the backing store. This allows us to
maintain the old behavior.
Bug: v8:6333
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: I6361d161cdb19878ba19ed51d6ba2fae99e8cdc0
Reviewed-on: https://chromium-review.googlesource.com/660125
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48197}
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 changes CPU check to use 'target_cpu' instead of 'v8_target_cpu'.
Bug: chromium:694255
Change-Id: Ic3ad5253e4e0b66b13e9f16a5842bcf49881fa52
Reviewed-on: https://chromium-review.googlesource.com/677994
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48119}
Along with BigInt.prototype. Their functions only have skeleton
implementations. The purpose of this change is to make it easier
to gradually increase test coverage (e.g. for toString(radix)).
Of course this is still behind the --harmony-bigint flag.
Bug: v8:6791
Change-Id: Ic307fd9165c56ac782fba18d648ce893daaa718f
Reviewed-on: https://chromium-review.googlesource.com/671209
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48094}
Removes
- SequentialMarkingDeque
- The ability to handle marking deque overflow
- BlackToGrey transitions
We switched to a different marking work list on M61 that fails
in OOM upon failing to allocate Segments used in the work list.
Bug: chromium:758570
Change-Id: I66e2ab912271bf84b085dccc9b4bdd96076b64fb
Reviewed-on: https://chromium-review.googlesource.com/632676
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48078}
This CL refactors allocation & reservation logic into a new
DefaultSerializerAllocator class. In upcoming work, this will be
further extended by a custom allocator for builtin serialization.
Additionally, this cleans up a bunch of cosmetics (encapsulation and
other nits).
Bug: v8:6624
Change-Id: Ibcf12a525c8fcb26d9c16b7a12fd598c37a0e10a
Reviewed-on: https://chromium-review.googlesource.com/650357
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48077}
This reverts commit ee5c31f335.
Reason for revert: Fixed compiler failure
Original change's description:
> Revert "[wasm] A simple allocator datastructure for off-the heap"
>
> This reverts commit 110d9ab005.
>
> Reason for revert: https://build.chromium.org/p/client.v8/builders/V8%20Linux64%20-%20debug%20builder/builds/26607
>
> Surprising we're seeing a failure on Linux 64 *after* CQ. Is the compiler there different?
>
> Original change's description:
> > [wasm] A simple allocator datastructure for off-the heap
> >
> > We'll use this allocator in a follow-up CL to:
> > - allocate speculative sizes of memory for a module that's being
> > compiled (e.g. 2*size of wasm code).
> > - each module will own such a sub-pool, and then use it to allocate
> > contiguous chunks of memory for code.
> >
> > The underlying assumptions for the chosen allocation strategy is that:
> > - the allocation granularity for pools is 1 page, so that no one page
> > is owned by more than one wasm module
> > - typical pool sizes (given module sizes) are multiple pages.
> > - modules and module instances are typically few and long lived. Typically,
> > we expect one module and one instance.
> >
> > This means we shouldn't expect fragmentations that lead to code being
> > non-allocatable, or prohibitively many ranges.
> >
> > The data structure just manages ranges of addresses. Virtual memory management
> > will be separate, as part of the responsibility of a "WasmHeap"
> > that will be introduced in the future. So will concurrency control.
> >
> > Bug:
> > Change-Id: Id99f46d10c25553b013054d994760f3c2a737c39
> > Reviewed-on: https://chromium-review.googlesource.com/669296
> > Commit-Queue: Mircea Trofin <mtrofin@chromium.org>
> > Reviewed-by: Eric Holk <eholk@chromium.org>
> > Reviewed-by: Brad Nelson <bradnelson@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#48053}
>
> TBR=bradnelson@chromium.org,mtrofin@chromium.org,eholk@chromium.org
>
> Change-Id: Id82fa341b77624e4971f24c4757a9a666a65930c
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Reviewed-on: https://chromium-review.googlesource.com/670141
> Reviewed-by: Mircea Trofin <mtrofin@chromium.org>
> Commit-Queue: Mircea Trofin <mtrofin@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#48054}
TBR=bradnelson@chromium.org,mtrofin@chromium.org,eholk@chromium.org
Change-Id: Ib6a7a3e6098d2689e60cdca85ec77e57e5295e48
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/670142
Commit-Queue: Mircea Trofin <mtrofin@chromium.org>
Reviewed-by: Mircea Trofin <mtrofin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48055}
This reverts commit 110d9ab005.
Reason for revert: https://build.chromium.org/p/client.v8/builders/V8%20Linux64%20-%20debug%20builder/builds/26607
Surprising we're seeing a failure on Linux 64 *after* CQ. Is the compiler there different?
Original change's description:
> [wasm] A simple allocator datastructure for off-the heap
>
> We'll use this allocator in a follow-up CL to:
> - allocate speculative sizes of memory for a module that's being
> compiled (e.g. 2*size of wasm code).
> - each module will own such a sub-pool, and then use it to allocate
> contiguous chunks of memory for code.
>
> The underlying assumptions for the chosen allocation strategy is that:
> - the allocation granularity for pools is 1 page, so that no one page
> is owned by more than one wasm module
> - typical pool sizes (given module sizes) are multiple pages.
> - modules and module instances are typically few and long lived. Typically,
> we expect one module and one instance.
>
> This means we shouldn't expect fragmentations that lead to code being
> non-allocatable, or prohibitively many ranges.
>
> The data structure just manages ranges of addresses. Virtual memory management
> will be separate, as part of the responsibility of a "WasmHeap"
> that will be introduced in the future. So will concurrency control.
>
> Bug:
> Change-Id: Id99f46d10c25553b013054d994760f3c2a737c39
> Reviewed-on: https://chromium-review.googlesource.com/669296
> Commit-Queue: Mircea Trofin <mtrofin@chromium.org>
> Reviewed-by: Eric Holk <eholk@chromium.org>
> Reviewed-by: Brad Nelson <bradnelson@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#48053}
TBR=bradnelson@chromium.org,mtrofin@chromium.org,eholk@chromium.org
Change-Id: Id82fa341b77624e4971f24c4757a9a666a65930c
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/670141
Reviewed-by: Mircea Trofin <mtrofin@chromium.org>
Commit-Queue: Mircea Trofin <mtrofin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48054}
We'll use this allocator in a follow-up CL to:
- allocate speculative sizes of memory for a module that's being
compiled (e.g. 2*size of wasm code).
- each module will own such a sub-pool, and then use it to allocate
contiguous chunks of memory for code.
The underlying assumptions for the chosen allocation strategy is that:
- the allocation granularity for pools is 1 page, so that no one page
is owned by more than one wasm module
- typical pool sizes (given module sizes) are multiple pages.
- modules and module instances are typically few and long lived. Typically,
we expect one module and one instance.
This means we shouldn't expect fragmentations that lead to code being
non-allocatable, or prohibitively many ranges.
The data structure just manages ranges of addresses. Virtual memory management
will be separate, as part of the responsibility of a "WasmHeap"
that will be introduced in the future. So will concurrency control.
Bug:
Change-Id: Id99f46d10c25553b013054d994760f3c2a737c39
Reviewed-on: https://chromium-review.googlesource.com/669296
Commit-Queue: Mircea Trofin <mtrofin@chromium.org>
Reviewed-by: Eric Holk <eholk@chromium.org>
Reviewed-by: Brad Nelson <bradnelson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48053}
This is a reland of dbfdd4f9e9
Original change's description:
> [heap] Turn on v8_enable_csa_write_barrier
>
> With this commit, write barrier is switched to use CodeStubAssembler.
>
> Bug: chromium:749486
> Change-Id: I7e0914bee971e4f3a3257740ae7c83b31f791bd9
> Reviewed-on: https://chromium-review.googlesource.com/598088
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Commit-Queue: Albert Mingkun Yang <albertnetymk@google.com>
> Cr-Commit-Position: refs/heads/master@{#48006}
Bug: chromium:749486
Change-Id: I00933d989568c82b5fbaf6203bb146c65f8e4282
Reviewed-on: https://chromium-review.googlesource.com/668636
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Albert Mingkun Yang <albertnetymk@google.com>
Cr-Commit-Position: refs/heads/master@{#48045}
This reverts commit dbfdd4f9e9.
Reason for revert: https://clusterfuzz.com/v2/testcase-detail/5493096547876864?noredirect=1
Original change's description:
> [heap] Turn on v8_enable_csa_write_barrier
>
> With this commit, write barrier is switched to use CodeStubAssembler.
>
> Bug: chromium:749486
> Change-Id: I7e0914bee971e4f3a3257740ae7c83b31f791bd9
> Reviewed-on: https://chromium-review.googlesource.com/598088
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Commit-Queue: Albert Mingkun Yang <albertnetymk@google.com>
> Cr-Commit-Position: refs/heads/master@{#48006}
TBR=ulan@chromium.org,albertnetymk@google.com
# Not skipping CQ checks because original CL landed > 1 day ago.
Bug: chromium:749486
Change-Id: I8cf6a3f1d2ea607a0160b37b797d743b88b004b5
Reviewed-on: https://chromium-review.googlesource.com/667018
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Albert Mingkun Yang <albertnetymk@google.com>
Cr-Commit-Position: refs/heads/master@{#48036}
This was supposedly a runtime flag, but we baked it into the snapshot
anyway.
Change-Id: I09d43183c4c2d59336c1077089119d6cb65dfd87
Reviewed-on: https://chromium-review.googlesource.com/664721
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48026}
With this commit, write barrier is switched to use CodeStubAssembler.
Bug: chromium:749486
Change-Id: I7e0914bee971e4f3a3257740ae7c83b31f791bd9
Reviewed-on: https://chromium-review.googlesource.com/598088
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Albert Mingkun Yang <albertnetymk@google.com>
Cr-Commit-Position: refs/heads/master@{#48006}
Previously instructions-arm64.h was alternatively defining or declaring
some constants based on whether or not ARM64_DEFINE_FP_STATICS was defined,
and it was assumed that exactly one file would include this header with
the macro defined.
In jumbo builds, the header guards in instructions-arm64.h meant that the
resulting state of the header file would be whichever of the two cases
that appeared first in the compilation unit. This would cause multiple
definitions in some cases and no definitions in some other cases (or if
you were really lucky, it would work out ok).
Let's move these constants to a separate source file temporarily, to be
excluded from jumbo compilation units. This code should eventually be
replaced with a cleaner solution.
Bug: chromium:746958
Change-Id: I7edb1821ef408afd50c6b236d63d3c07f955b58f
Reviewed-on: https://chromium-review.googlesource.com/663898
Commit-Queue: Mostyn Bramley-Moore <mostynb@opera.com>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48003}
BigInt is a new primitive type of arbitrary precision integers,
proposed in https://tc39.github.io/proposal-bigint.
This CL introduces a corresponding instance type, map, and C++
class to V8 and adds BigInt support to a few operations (see the
test file). Much more is to come. Also, the concrete representation
of BigInts is not yet fixed, currently a BigInt is simply a wrapped
Smi.
Bug: v8:6791
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: Ia2901948efd7808f17cfc945f0d56e23e8ae0b45
Reviewed-on: https://chromium-review.googlesource.com/657022
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47956}
TSAN finds data races in generated JavaScript code that use
access the SharedArrayBuffer backing store racily. These are races, but
they are OK in the sense that the JavaScript memory model allows for the
potential bad behavior they could introduce (e.g. potentially tearing
reads). Relaxed atomics could be used here instead, but that could
introduce performance regressions.
This change adds TSAN annotations to the TypedArray reads/writes to
prevent TSAN from warning about them.
Bug: chromium:722871
Change-Id: I0776475f02a352b678ade7d32ed6bd4a6be98c36
Reviewed-on: https://chromium-review.googlesource.com/656509
Commit-Queue: Ben Smith <binji@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47929}
This removes the ability to create a copy of a code-stub with a given
replacement pattern applied. It is in preparation of having the ability
to write-protect code objects.
R=ishell@chromium.org
BUG=v8:6409
Change-Id: Id7528b3bfc53ece73d8c58b0ac96c6e5702a9d45
Reviewed-on: https://chromium-review.googlesource.com/654605
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47914}
This finally allows to include the factory.h header without having to
also inlcude the object-inl.h inline header. It will in turn enable the
removal of the last inline header inclusion violation.
R=marja@chromium.org
Change-Id: Ice2821e1f74cf428d80c8ebf606a218026f37677
Reviewed-on: https://chromium-review.googlesource.com/654862
Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47880}
This reduces the arm32 binary by around 20kB.
R=jkummerow@chromium.org, mstarzinger@chromium.org
Bug: v8:6055
Change-Id: If9098e49793b29dceb8292aff6f668ca28a07728
Reviewed-on: https://chromium-review.googlesource.com/652427
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47863}
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}
