b6f7ea5805
As discussed in https://docs.google.com/document/d/1sBdGe8RHgeYP850cKSSgGABTyfMdvaEWLy-vertuTCo/edit?ts=5b3ba5cc#, this CL introduces a new bytecode (CloneObject), and a new IC type. In this prototype implementation, the type feedback looks like the following: Uninitialized case: { uninitialized_sentinel, uninitialized_sentinel } Monomorphic case: { weak 'source' map, strong 'result' map } Polymorphic case: { WeakFixedArray with { weak 'source' map, strong 'result' map }, cleared value } Megamorphic case: { megamorphic_sentinel, cleared_Value } In the fast case, Object cloning is done by allocating an object with the saved result map, and a shallow clone of the fast properties from the source object, as well as cloned fast elements from the source object. If at any point the fast case can't be taken, the IC transitions to the slow case and remains there. This prototype CL does not include any TurboFan optimization, and the CloneObject operation is merely reduced to a stub call. It may still be possible to get some further improvements by somehow incorporating compile-time boilerplate elements into the cloned object, or simplifying how the boilerplate elements are inserted into the object. In terms of performance, we improve the ObjectSpread score in JSTests/ObjectLiteralSpread/ by about 8x, with substantial improvements over the Babel and ObjectAssign scores. R=gsathya@chromium.org, mvstanton@chromium.org, rmcilroy@chromium.org, neis@chromium.org, bmeurer@chromium.org BUG=v8:7611 Change-Id: I79e1796eb77016fb4feba0e1d3bb9abb348c183e Reviewed-on: https://chromium-review.googlesource.com/1127472 Commit-Queue: Caitlin Potter <caitp@igalia.com> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org> Reviewed-by: Michael Stanton <mvstanton@chromium.org> Reviewed-by: Georg Neis <neis@chromium.org> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org> Cr-Commit-Position: refs/heads/master@{#54595} |
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| gni | ||
| include | ||
| infra | ||
| samples | ||
| src | ||
| test | ||
| testing | ||
| third_party | ||
| tools | ||
| .clang-format | ||
| .editorconfig | ||
| .git-blame-ignore-revs | ||
| .gitattributes | ||
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| .gn | ||
| .vpython | ||
| .ycm_extra_conf.py | ||
| AUTHORS | ||
| BUILD.gn | ||
| ChangeLog | ||
| CODE_OF_CONDUCT.md | ||
| codereview.settings | ||
| DEPS | ||
| LICENSE | ||
| LICENSE.fdlibm | ||
| LICENSE.strongtalk | ||
| LICENSE.v8 | ||
| LICENSE.valgrind | ||
| OWNERS | ||
| PRESUBMIT.py | ||
| README.md | ||
| snapshot_toolchain.gni | ||
| WATCHLISTS | ||
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.