Go to file
Georg Neis 90a2430388 Optimize JSCallWithArrayLike with diamond speculation when probable arguments list is empty literal array
The JSCallWithArraylike can be replaced with a JSCall if its probable arguments list is empty literal array. This replacement will introduce a deoptimization check to make sure the length of arguments list is 0 at runtime.

This CL change this optimization to a diamond speculation which may help avoid deoptimization once and keep the fast path. This change may benefit a following usecase,

function calcMax(testArray) {
     Array.max = function(array) {
         return Math.max.apply(Math, array);
     };

     var result = [];
     for (var i = 0; i < testArray.length - 3; i++) {
         var positiveNumbers = [];
         for (var j = 0; j < 3; j++) {
             if (testArray[i + j] > 0) {
                 positiveNumbers.push(testArray[i + j]);
             }
         }
         result.push(Array.max(positiveNumbers));
     }
     return result;
 }

 testArray = [-1, 2, 3, -4, -5, -6, -7, -8, -9, 10];

 for (var i = 0; i < 1000000; i++) {
     calcMax(testArray);
 }

Bug: v8:9974
Change-Id: I595627e2fd937527350c8f8652d701c791b41dd3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2967757
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75636}
2021-07-08 11:38:58 +00:00
.github [github] Close PRs created on the V8 GitHub mirror automatically 2021-01-12 08:39:59 +00:00
bazel [bazel] Remove linkstatic from v8_library 2021-07-05 15:10:38 +00:00
build_overrides [build] Remove obsolete gn flag 2021-01-11 15:50:59 +00:00
custom_deps Use relative paths to OWNERS files 2019-08-12 13:52:52 +00:00
docs Add OWNERS for docs/ 2019-05-15 12:06:15 +00:00
gni [bigint] Toom-Cook multiplication 2021-07-07 10:12:26 +00:00
include cppgc: Allow for differentiating committed and physical size on a page 2021-07-07 22:07:22 +00:00
infra Rename '- reclient' to '(reclient)'. 2021-07-08 07:20:12 +00:00
samples Reland "[api] Add v8::Isolate::ThrowError helper" 2021-04-16 11:48:05 +00:00
src Optimize JSCallWithArrayLike with diamond speculation when probable arguments list is empty literal array 2021-07-08 11:38:58 +00:00
test Optimize JSCallWithArrayLike with diamond speculation when probable arguments list is empty literal array 2021-07-08 11:38:58 +00:00
testing [macros] Upstream Google3 changes 2021-06-24 16:36:14 +00:00
third_party [base] Move utils/vector.h to base/vector.h 2021-06-18 13:33:13 +00:00
tools [tools] Default to printing $pc when jco is called without args 2021-07-07 17:24:01 +00:00
.bazelrc [bazel] Compile V8 with bazel 2021-06-15 14:52:09 +00:00
.clang-format [clang-format] Don't derive pointer alignment 2017-01-17 09:28:19 +00:00
.clang-tidy [tool] Remove unfixed clang-tidy warnings to ease use. 2018-10-26 07:40:32 +00:00
.editorconfig Add .editorconfig 2017-07-28 13:39:24 +00:00
.flake8 Add .flake8 to allow for python style checking. 2019-07-19 21:44:03 +00:00
.git-blame-ignore-revs [infra] Update .git-blame-ignore-revs 2020-03-03 12:59:13 +00:00
.gitattributes .gitattributes: Mark minified emscripten js files as -diff 2018-09-19 16:27:10 +00:00
.gitignore [log] Include tickprocessor log files in git 2021-06-21 15:26:29 +00:00
.gn Revert "[build] Separate out inspector as a shared library" 2021-07-02 16:15:20 +00:00
.mailmap Restore consistency between .mailmap and AUTHORS 2021-06-24 08:58:04 +00:00
.vpython [tools] Implement confidence-based number of runs 2019-05-09 09:42:28 +00:00
.ycm_extra_conf.py Fix ycm config for headers without source 2019-12-09 11:59:21 +00:00
AUTHORS Promises: Add is_silent flag and ignore rejects when it is set 2021-07-07 08:48:00 +00:00
BUILD.bazel [build] Move ObjectType out of code-assembler.h 2021-07-07 10:19:16 +00:00
BUILD.gn [build] Move ObjectType out of code-assembler.h 2021-07-07 10:19:16 +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
COMMON_OWNERS Remove ulan@ from OWNERS 2021-06-08 13:10:21 +00:00
DEPS Update V8 DEPS. 2021-07-08 03:48:41 +00:00
DIR_METADATA Add DIR_METADATA files to v8. 2020-10-20 22:12:28 +00:00
ENG_REVIEW_OWNERS Update ENG_REVIEW_OWNERS 2021-02-25 14:28:32 +00:00
INFRA_OWNERS Add team members as owners 2020-08-18 08:29:04 +00:00
INTL_OWNERS add ftang as owner 2020-04-24 19:19:36 +00:00
LICENSE [wasm] Draft version of C/C++ Wasm API 2019-04-17 16:00:26 +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
MIPS_OWNERS [mips] Request to be an owner of MIPS files 2020-11-23 09:43:49 +00:00
OWNERS Allow COMMON_OWNERS to LGTM .mailmap CLs 2021-06-24 07:21:03 +00:00
PPC_OWNERS Adding myself to relevant OWNERS files. 2020-11-02 16:37:28 +00:00
PRESUBMIT.py [bigint] Move multiplication to src/bigint/ 2021-04-19 15:40:43 +00:00
README.md [docs] Change links from old wiki to v8.dev 2019-03-07 12:13:30 +00:00
RISCV_OWNERS [riscv64] Change one of the owners for RISCV. 2021-04-20 14:39:26 +00:00
S390_OWNERS Adding myself to relevant OWNERS files. 2020-11-02 16:37:28 +00:00
WATCHLISTS [bazel] Add bazel files to watchlist 2021-06-17 09:26:11 +00:00
WORKSPACE [bazel] Adds ICU 2021-06-30 12:54:15 +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://v8.dev/docs

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 at v8.dev/docs/contribute.