Reland "[cleanup] Harden the SubString CSA/Runtime implementations."

This is a reland of 6d5b54df82e27a82811a836dcdbbfe26829f0e6d
Original change's description:
> [cleanup] Harden the SubString CSA/Runtime implementations.
>
> Remove the self-healing for invalid parameters in the
> CodeStubAssembler::SubString helper and the %SubString runtime function,
> which is used as a fallback for the CodeStubAssembler implementation.
> All call sites must do appropriate parameter validation anyways now that
> the self-hosted JavaScript builtins using these helpers are gone, and we
> have proper contracts with the uses.
>
> Also remove the context parameter from the CodeStubAssembler::SubString
> method, which is unnecessary, since this can no longer throw an
> exception.
>
> Bug: v8:5269, v8:6936, v8:7109, v8:7137
> Change-Id: I19d93bad5f41faa0561c4561a48f78fcba99a549
> Reviewed-on: https://chromium-review.googlesource.com/795720
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#49702}

Bug: v8:5269, v8:6936, v8:7109, v8:7137
Change-Id: I5e84998a2dd3990d7981505b401ffc770e0b7ac5
Reviewed-on: https://chromium-review.googlesource.com/913130
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51265}
6 files changed
tree: 3880cdd1d9ad8011acdfc2eae223ff7a2c159aa7
  1. benchmarks/
  2. build_overrides/
  3. docs/
  4. gni/
  5. include/
  6. infra/
  7. samples/
  8. src/
  9. test/
  10. testing/
  11. third_party/
  12. tools/
  13. .clang-format
  14. .editorconfig
  15. .git-blame-ignore-revs
  16. .gitignore
  17. .gn
  18. .vpython
  19. .ycm_extra_conf.py
  20. AUTHORS
  21. BUILD.gn
  22. ChangeLog
  23. CODE_OF_CONDUCT.md
  24. codereview.settings
  25. DEPS
  26. LICENSE
  27. LICENSE.fdlibm
  28. LICENSE.strongtalk
  29. LICENSE.v8
  30. LICENSE.valgrind
  31. OWNERS
  32. PRESUBMIT.py
  33. README.md
  34. snapshot_toolchain.gni
  35. 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://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.