commit | 6452b26a4bd746928937124d674e6dc3b9031396 | [log] [tgz] |
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author | Daniel Clifford <danno@chromium.org> | Mon Oct 23 18:41:42 2017 |
committer | Commit Bot <commit-bot@chromium.org> | Tue Oct 24 06:39:47 2017 |
tree | 49e4e332837acfecafd131abc3c929d9282edc5b | |
parent | b422ba3e2f4b2eccf32baa278736ffbee5c93991 [diff] |
Reimplement Array.prototype.slice in CSA and C++ Previously, V8's slice was implemented in a combination of C++ and a Javascript fallback. The disadvantage of this approach was that the fast-path required a call through the CEntryStub, which introduced considerable overhead for small arrays with fast elements kinds. Now the implementation primarily uses the CSA to generate both the full spec-complaint implementation as well as fast paths for argument objects and arrays with fast elements kinds. The CSA implementation uses a C++ implementation fallback in select situations where the the complexity of a CSA implementation would be too great and the CEntryStub overhead is not decisive (e.g. slices of dictionary elements arrays). Performance results on semi-random arrays with small number of elements (old vs. new): smi copy: 48.7 ms vs. 12 ms smi slice: 43.5 ms 14.8 ms object copy: 35.5 ms 7.7 ms object slice: 38.7 ms 8.8 ms dictionary slice: 2398.3 ms vs. 5.4 ms fast sloppy arguments slice: 9.6 ms vs. 7.2 ms slow sloppy arguments slice: 28.9 ms vs. 8.5 ms As a bonus, the new implementation is fully spec-compliant and fixes at least one existing bug. The design document for Array.prototype builtin rework can be found at https://goo.gl/wFHe2n Bug: v8:1956,v8:6601,v8:6710,v8:6978 Change-Id: Ia0155bedcf39b4577605ff754f416c2af938efb7 Reviewed-on: https://chromium-review.googlesource.com/574710 Commit-Queue: Daniel Clifford <danno@chromium.org> Reviewed-by: Benedikt Meurer <bmeurer@chromium.org> Cr-Commit-Position: refs/heads/master@{#48853}
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
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/*
Please follow the instructions mentioned on the V8 wiki.