[typedarray] Make JSTypedArray::length authoritative.

This is the first step towards full huge typed array support in V8.
Before this change, the JSTypedArray::length and the elements backing
store length (FixedTypedArrayBase::length) were used more or less
interchangeably to determine the number of elements in a JSTypedArray.

With this change we disentangle these two lengths, and instead make
JSTypedArray::length authoritative. For on-heap typed arrays, the
FixedTypedArrayBase::length will remain the number of elements in the
backing store, but for the off-heap typed arrays, this length will be
set to 0 (matching the fact that the FixedTypedArrayBase instance does
not contain any elements itself).

This also unifies the JSTypedArray::set_/length() and length_value()
methods to only have JSTypedArray::set_/length() which returns/takes
size_t values. Currently this still requires the values to be in Smi
range, but later we will extend this to allow arbitrary size_t values
(in the safe integer range).

Bug: v8:4153, v8:7881
Change-Id: Iff9089130bb31fa9e08e0cf913e7ab52c3dbf107
Cq-Include-Trybots: luci.chromium.try:linux-blink-rel
Doc: http://doc/1Z-wM2qwvAuxH46e9ivtkYvKzzwYZg8ymm0x0wJaomow
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1543729
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60648}
28 files changed
tree: 1c6068d387c0ed9844a21b675edae7e3fa902fa4
  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
  11. BUILD.gn
  13. ChangeLog
  14. DEPS
  16. LICENSE.fdlibm
  17. LICENSE.strongtalk
  18. LICENSE.v8
  19. LICENSE.valgrind
  20. OWNERS
  21. PRESUBMIT.py
  22. README.md
  24. benchmarks/
  25. build_overrides/
  26. codereview.settings
  27. custom_deps/
  28. docs/
  29. gni/
  30. include/
  31. infra/
  32. samples/
  33. snapshot_toolchain.gni
  34. src/
  35. test/
  36. testing/
  37. third_party/
  38. tools/

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/*


Please follow the instructions mentioned at v8.dev/docs/contribute.