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Benedikt Meurer 1f8dcc5d2e [builtins] Optimize PromiseResolveThenableJob for the common case.
The idea here is that in case the `thenable` is a JSPromise and `then`
is the initial `Promise.prototype.then` method, and the @@species lookup
chain is intact, we can skip creating the temporary promise and the
closures (with the shared context), and instead directly call into our
PerformPromiseThen. This is sound since - given above mentioned
conditions - our short-cut

  PerformPromiseThen(thenable, undefined, undefined, promise_to_resolve)

is not observably different from the actual

  resolve, reject = CreateResolvingFunctions(promise_to_resolve)
  result_capability = NewPromiseCapability(%Promise%)
  PerformPromiseThen(thenable, resolve, reject, result_capability)

except through PromiseHooks (and potentially via the async stack
traces). So we disable the fast-path if either promise hooks are enabled
or the debugger is active for now.

This improves the performance on the wikipedia benchmark by 20-25% and
the bluebird-doxbee benchmark by around 20%.

Bug: v8:7253
Change-Id: I23c92ad365c2b71d65057573f2d8febe2afe00b0
Reviewed-on: https://chromium-review.googlesource.com/911800
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51261}
2018-02-13 05:36:39 +00:00
benchmarks Fix common misspellings 2017-08-02 09:35:28 +00:00
build_overrides [ndk] Change android ndk root for v8 2018-01-11 08:10:33 +00:00
docs [Docs] Removed unused docs because they are moved to GitHub 2015-11-19 10:23:30 +00:00
gni [GN][MIPS] Add ldso_path and gcc_target_rpath config on MIPS 2018-01-30 11:51:24 +00:00
include [api] GetOwnPropertyNames and GetPropertyNames should return Strings 2018-02-12 19:02:14 +00:00
infra [build] Remove last vestiges of gyp from MB configs 2018-02-12 13:53:02 +00:00
samples [gyp] move gyp files from src to gypfiles. 2018-01-23 09:54:36 +00:00
src [builtins] Optimize PromiseResolveThenableJob for the common case. 2018-02-13 05:36:39 +00:00
test [builtins] Optimize PromiseResolveThenableJob for the common case. 2018-02-13 05:36:39 +00:00
testing [gyp] move build targets for tests to gypfiles. 2018-01-30 06:31:00 +00:00
third_party Move detect_v8_host_arch out of gypfiles. 2018-01-31 08:21:01 +00:00
tools Whitespace CL 2018-02-13 01:06:39 +00:00
.clang-format [clang-format] Don't derive pointer alignment 2017-01-17 09:28:19 +00:00
.editorconfig Add .editorconfig 2017-07-28 13:39:24 +00:00
.git-blame-ignore-revs [build] Add DEPS formatting to hyper-blame 2017-10-09 14:08:45 +00:00
.gitignore [gyp] remove gyp files. 2018-02-08 20:04:06 +00:00
.gn For building v8 using gn on aix_ppc64, linux_s390x and linux_ppc64(both LE and BE). 2017-05-12 01:35:09 +00:00
.vpython Add a comment for the VPython dep 2017-10-25 12:23:35 +00:00
.ycm_extra_conf.py [ycm] Switch from gnu++11 to gnu++14 2017-11-27 07:48:21 +00:00
AUTHORS Reland: Reimplement Object.entries/values as CSA to optimize performance. 2018-02-08 10:12:32 +00:00
BUILD.gn [api] remove legacy debug API. 2018-02-12 14:49:29 +00:00
ChangeLog [tools] Merge ChangeLog from latest release 2017-12-19 12:30:56 +00:00
CODE_OF_CONDUCT.md Explicitly state that the Chromium Code of Conduct also applies to V8 2016-03-02 09:51:24 +00:00
codereview.settings Make Gerrit the default code review for V8 2017-06-30 17:37:37 +00:00
DEPS [build] Download gcmole and jsfunfuzz controlled by gclient flag 2018-02-12 13:32:03 +00:00
LICENSE Updates to the license information of third party components. 2015-06-16 12:37:50 +00:00
LICENSE.fdlibm Add LICENSE.fdlibm for all the fdlibm imported sources. 2016-06-09 07:17:03 +00:00
LICENSE.strongtalk Add LICENSE.v8, LICENSE.strongtalk and LICENSE.valgrind to the v8 2011-02-03 07:10:06 +00:00
LICENSE.v8 Add LICENSE.v8, LICENSE.strongtalk and LICENSE.valgrind to the v8 2011-02-03 07:10:06 +00:00
LICENSE.valgrind Add LICENSE.v8, LICENSE.strongtalk and LICENSE.valgrind to the v8 2011-02-03 07:10:06 +00:00
OWNERS Update top-level OWNERS. 2018-01-19 08:37:12 +00:00
PRESUBMIT.py [gyp] remove gyp files. 2018-02-08 20:04:06 +00:00
README.md [Docs] Removed unused docs because they are moved to GitHub 2015-11-19 10:23:30 +00:00
snapshot_toolchain.gni MIPS[64]: Generate snapshots on MIPS big-endian targets 2017-11-24 19:00:32 +00:00
WATCHLISTS [gyp] remove gyp files. 2018-02-08 20:04:06 +00:00

V8 JavaScript Engine

V8 is Google's open source JavaScript engine.

V8 implements ECMAScript as specified in ECMA-262.

V8 is written in C++ and is used in Google Chrome, the open source browser from Google.

V8 can run standalone, or can be embedded into any C++ application.

V8 Project page: https://github.com/v8/v8/wiki

Getting the Code

Checkout depot tools, and run

    fetch v8

This will checkout V8 into the directory v8 and fetch all of its dependencies. To stay up to date, run

    git pull origin
    gclient sync

For fetching all branches, add the following into your remote configuration in .git/config:

    fetch = +refs/branch-heads/*:refs/remotes/branch-heads/*
    fetch = +refs/tags/*:refs/tags/*

Contributing

Please follow the instructions mentioned on the V8 wiki.