[json] Speed up two-byte json substring internalization

Inputs to JSON can be two-byte because payload strings can contain two-byte
characters, without actually having any one-byte property key. Rather than
eagerly converting the string to one-byte, we can perform a string-table lookup
with a two-byte string key; only converting the result to one-byte if it's a
new key.

This speeds up json parsing of two-byte json from the Youtube benchmark by 20%.

Change-Id: If6d4a37d331724f48b008aef8ec3e28d366cd038
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1619866
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61680}
5 files changed
tree: 09a2b00119aa71a6309503c768f5c07766fef7e3
  1. .clang-format
  2. .clang-tidy
  3. .editorconfig
  4. .git-blame-ignore-revs
  5. .gitattributes
  6. .gitignore
  7. .gn
  8. .vpython
  9. .ycm_extra_conf.py
  10. AUTHORS
  11. BUILD.gn
  12. CODE_OF_CONDUCT.md
  13. COMMON_OWNERS
  14. ChangeLog
  15. DEPS
  16. ENG_REVIEW_OWNERS
  17. INFRA_OWNERS
  18. LICENSE
  19. LICENSE.fdlibm
  20. LICENSE.strongtalk
  21. LICENSE.v8
  22. LICENSE.valgrind
  23. OWNERS
  24. PRESUBMIT.py
  25. README.md
  26. WATCHLISTS
  27. benchmarks/
  28. build_overrides/
  29. codereview.settings
  30. custom_deps/
  31. docs/
  32. gni/
  33. include/
  34. infra/
  35. samples/
  36. src/
  37. test/
  38. testing/
  39. third_party/
  40. tools/
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.