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mvstanton aea3ce3df3 [TypeFeedbackVector] Root feedback vectors at function literal site. 
TypeFeedbackVectors are strongly rooted by a closure. However, in modern
JavaScript closures are created and abandoned more freely. An important
closure may not be present in the root-set at time of garbage collection,
even though we've cached optimized code and use it regularly. For
example, consider leaf functions in an event dispatching system. They may
well be "hot," but tragically non-present when we collect the heap.

Until now, we've relied on a weak root to cache the feedback vector in
this case. Since there is no way to signal intent or relative importance,
this weak root is as susceptible to clearing as any other weak root at
garbage collection time.

Meanwhile, the feedback vector has become more important. All of our
ICs store their data there. Literal and regex boilerplates are stored there.
If we lose the vector, then we not only lose optimized code built from
it, we also lose the very feedback which allowed us to create that optimized
code. Therefore it's vital to express that dependency through the root
set.

This CL does this by creating a strong link to a feedback
vector at the instantiation site of the function closure.
This instantiation site is in the code and feedback vector
of the outer closure.

BUG=v8:5456

Review-Url: https://codereview.chromium.org/2674593003
Cr-Commit-Position: refs/heads/master@{#42953}
2017-02-06 10:18:05 +00:00
benchmarks Revert "Refactoring: Make gtest testsuite the default." 2014-09-02 09:17:26 +00:00
build_overrides Remove build_overrides/v8.gni. 2017-01-26 20:18:58 +00:00
docs [Docs] Removed unused docs because they are moved to GitHub 2015-11-19 10:23:30 +00:00
gni [foozzie] Support multi-architecture builds 2017-02-02 11:32:52 +00:00
gypfiles Reland "[test] Add back lsan leak detection" 2017-02-01 10:39:28 +00:00
include [debugger] remove mirror cache and v8::Debug::GetMirror. 2017-02-02 14:22:15 +00:00
infra [build] Let v8gen support mipsel architectures 2017-02-06 09:28:07 +00:00
samples Reland of land "Turn libbase into a component" (patchset #1 id:1 of https://codereview.chromium.org/2396933002/ ) 2016-10-07 07:56:52 +00:00
src [TypeFeedbackVector] Root feedback vectors at function literal site. 2017-02-06 10:18:05 +00:00
test [TypeFeedbackVector] Root feedback vectors at function literal site. 2017-02-06 10:18:05 +00:00
testing Use GTEST_LANG_CXX11 in V8 2016-07-25 13:06:42 +00:00
third_party Adapt String::find method via StringUtil adapter. 2017-02-03 22:17:24 +00:00
tools [TypeFeedbackVector] Root feedback vectors at function literal site. 2017-02-06 10:18:05 +00:00
.clang-format [clang-format] Don't derive pointer alignment 2017-01-17 09:28:19 +00:00
.gitignore Revert of [wasm] include JS conformance tests in Wasm mjsunit tests (patchset #5 id:80001 of https://codereview.chromium.org/2660903003/ ) 2017-01-31 19:59:30 +00:00
.gn [build] Roll build a3b623a:11a223f 2016-11-29 11:17:15 +00:00
.ycm_extra_conf.py Use C++11 / gnu++11, not 0x 2016-03-22 15:24:43 +00:00
AUTHORS [counters] Add UseCounters for 'f() = 0' syntax 2016-12-27 17:48:40 +00:00
BUILD.gn [foozzie] Support multi-architecture builds 2017-02-02 11:32:52 +00:00
ChangeLog [Release] Update ChangeLog file 2016-02-17 21:29:09 +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 Use v8-reviews@ for review mail, so v8-dev@ is free for dev discussions 2015-09-09 08:14:11 +00:00
DEPS Update V8 DEPS. 2017-02-06 04:25:54 +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
Makefile Make enabling of CSA verifier a build-time flag 2017-01-27 11:32:27 +00:00
Makefile.android [build] Fix d8-for-Android builds 2016-05-20 12:10:45 +00:00
OWNERS Make clemensh owner (wasm, asmjs and general) 2017-01-13 10:20:44 +00:00
PRESUBMIT.py [test] Only run presubmit for changed status files 2016-12-06 11:42:11 +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 Use clang for snapshot_toolchain by default, except on ChromeOS. 2016-08-23 14:04:27 +00:00
WATCHLISTS [inspector] added devtools-reviews@chromium.org in WATCHLISTS for inspector 2016-09-29 15:16:54 +00:00

README.md

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.