[intl] Avoid a temporary allocation while converting to ICU string

If we need to build an icu::UnicodeString for a string that is currently
in one-byte representation, we first have to expand the string's content
into a two-byte representation. Doing so involves allocating an array,
which is slow. With this change, we can convert short strings on the
stack instead to save time. The cutoff length for what counts as "short"
is pretty arbitrary, but we believe many strings fit into an 80-column
line. This increases the score of cdjs in JetStream 2 by 35% on my
machine, because cdjs is basically a test of localeCompare throughput.

Bug: v8:9305

Change-Id: Iba081ac5a8fa7659edf06ac97ba8acf3f8328d59
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1630848
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61901}
1 file changed
tree: 37985ec7297b160bee93c602b915db88f2c37fd4
  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. MIPS_OWNERS
  24. OWNERS
  25. PPC_OWNERS
  26. PRESUBMIT.py
  27. README.md
  28. S390_OWNERS
  29. WATCHLISTS
  30. benchmarks/
  31. build_overrides/
  32. codereview.settings
  33. custom_deps/
  34. docs/
  35. gni/
  36. include/
  37. infra/
  38. samples/
  39. src/
  40. test/
  41. testing/
  42. third_party/
  43. 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.