Reland "[heap] Make trampoline CodeDataContainers immutable and deduplicate them"

Fixed by 6644f2b87239dbe8689697aa23a366b5881ec367
(https://chromium-review.googlesource.com/c/v8/v8/+/1605728)

This is a reland of 652e32f9f95e7f65bf1808eeb9e48eeacb35c07f

Original change's description:
> [heap] Make trampoline CodeDataContainers immutable and deduplicate them
>
> Moves all trampoline CodeDataContainers to read-only space, making them
> immutable. Containers with no 'kind specific flags' set or 'promise
> rejection' flag are deduplicated by replacing them with the new canonical
> CodeDataContainers roots.
>
> This saves around 36KB from the snapshot.
>
>     RO_SPACE  NEW_SPACE  OLD_SPACE  CODE_SPACE  MAP_SPACE  LO_SPACE
> old    32048          0     225944      149280      20240         0
> new    32120          0     189344      149280      20240         0
>
> Bug: v8:7464
> Change-Id: Iedd538a86311ef501cd88c90ec75e1308195762f
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1601257
> Commit-Queue: Maciej Goszczycki <goszczycki@google.com>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Dan Elphick <delphick@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#61378}

Bug: v8:7464
Change-Id: Ib98577d7d6c8c1205c94bf8c57d9cb38f51fdad3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1609539
Commit-Queue: Maciej Goszczycki <goszczycki@google.com>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61451}
7 files changed
tree: 1e552b19815a75ba02ffd96cc3525b830b38c4ce
  1. benchmarks/
  2. build_overrides/
  3. custom_deps/
  4. docs/
  5. gni/
  6. include/
  7. infra/
  8. samples/
  9. src/
  10. test/
  11. testing/
  12. third_party/
  13. tools/
  14. .clang-format
  15. .clang-tidy
  16. .editorconfig
  17. .git-blame-ignore-revs
  18. .gitattributes
  19. .gitignore
  20. .gn
  21. .vpython
  22. .ycm_extra_conf.py
  23. AUTHORS
  24. BUILD.gn
  25. ChangeLog
  26. CODE_OF_CONDUCT.md
  27. codereview.settings
  28. DEPS
  29. LICENSE
  30. LICENSE.fdlibm
  31. LICENSE.strongtalk
  32. LICENSE.v8
  33. LICENSE.valgrind
  34. OWNERS
  35. PRESUBMIT.py
  36. README.md
  37. snapshot_toolchain.gni
  38. WATCHLISTS
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://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.