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Ulan Degenbaev 40c34606a7 [heap] Instrument mark-compact to track retaining paths for debugging.
This patch adds a new intrinsic: %DebugTrackRetainingPath(object).
Calling the intrinsic in JS code saves a weak reference to the given
object in GC internal table of tracked objects.

Each subsequent full GC prints to stdout the retaining path for each
tracked object (if it is still alive). The retaining path is the real
path that the marker took from the root set to the tracked object.

This is useful for investigating of memory leaks:
1) Add %DebugTrackRetainingPath(leaking_object) in JS code.
For example:
  function foo() {
    let x = { bar: "bar"};
    %DebugTrackRetainingPath(x);
    return () => { return x; }
  }

  let closure = foo();
  gc();

2) Run d8 with --allow-natives-syntax --track-retaining-path --expose-gc.

3) Check the retaining path in stdout.

For more detailed inspection, run d8 in gdb and set breakpoint in

v8: :internal::Heap::PrintRetainingPath.
Change-Id: I01a0faac1e009bc6c321fa75613900b49d2b036f
Reviewed-on: https://chromium-review.googlesource.com/575972
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46766}
2017-07-19 14:06:59 +00:00
benchmarks Revert "Refactoring: Make gtest testsuite the default." 2014-09-02 09:17:26 +00:00
build_overrides Remove build_override for macOS min SDK and deployment target. 2017-07-14 18:24:44 +00:00
docs [Docs] Removed unused docs because they are moved to GitHub 2015-11-19 10:23:30 +00:00
gni [build] Dump build configuration for all v8 executables 2017-06-29 08:06:45 +00:00
gypfiles Remove x87 port 2017-07-18 18:20:40 +00:00
include [heap] Add API to set heap semi-space limits in KB. 2017-07-19 12:53:27 +00:00
infra Don't disable the sysroot on GCC 2017-07-19 08:48:13 +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 [heap] Instrument mark-compact to track retaining paths for debugging. 2017-07-19 14:06:59 +00:00
test MIPS[64]: Implement MSA Bit instructions in simulator 2017-07-19 13:42:02 +00:00
testing Use GTEST_LANG_CXX11 in V8 2016-07-25 13:06:42 +00:00
third_party Remove myself from non-toplevel owners files 2017-06-28 10:00:48 +00:00
tools [build] Add ubsan blacklist file 2017-07-19 11:33:11 +00:00
.clang-format [clang-format] Don't derive pointer alignment 2017-01-17 09:28:19 +00:00
.gitignore [wasm] Remove the wasm-asmjs fuzzer 2017-06-21 10:59:35 +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
.ycm_extra_conf.py Use C++11 / gnu++11, not 0x 2016-03-22 15:24:43 +00:00
AUTHORS [build] Set MSVS .obj folders in gyp for v8_base 2017-06-30 12:40:19 +00:00
BUILD.gn Remove x87 port 2017-07-18 18:20:40 +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 Make Gerrit the default code review for V8 2017-06-30 17:37:37 +00:00
DEPS Update V8 DEPS. 2017-07-19 03:48:13 +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 Remove x87 port 2017-07-18 18:20:40 +00:00
Makefile.android [build] Fix d8-for-Android builds 2016-05-20 12:10:45 +00:00
OWNERS Add COMPONENT tags to OWNERS files where appropriate 2017-05-22 10:15:28 +00:00
PRESUBMIT.py [test] Automatically add a noi18n bot for changes affecting Intl 2017-06-06 13:01:14 +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]: Add support for big endian build using GN 2017-06-02 15:02:18 +00:00
WATCHLISTS [V8Tracing] Add lpy@ and fmeawad@ into watchlist for tracing/. 2017-05-22 19:40:17 +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.