[generators] remove SuspendFlags enum and related code

SuspendFlags was originally used by the suspend operation to determine
which field to record the bytecode offset of a suspended generator, and
the value the generator was resumed with. For async generators, await
operations would use a separate field, in order to preserve the previous
yield input value. This was important to ensure `function.sent`
continued to function correctly.

As function.sent is being retired, this allows the removal of support
for that. Given that this was the only real need for SuspendFlags in the
first place (with other uses tacked on as a hack), this involves several
other changes as well:

- Modification of MacroAssembler AssertGeneratorObject. No longer
  accepts a SuspendFlags parameter to determine which type of check to
  perform.
- Removal of `flags` operand from SuspendGenerator bytecode, and the
  GeneratorStore js-operator.
- Removal of `flags` parameter from ResumeGeneratorTrampoline builtins.
- Removal of Runtime functions, interpreter intrinsics and
  AccessBuilders associated with the [[await_input_or_debug_pos]] field
  in JSAsyncGeneratorObject, as this field no longer exists.
- Addition of a new `Yield` AST node (subclass of Suspend) in order to
  prevent the need for the other SuspendFlag values.

BUG=v8:5855
TBR=bmeurer@chromium.org

Change-Id: Iff2881e4742497fe5b774915e988c3d9d8fbe487
Reviewed-on: https://chromium-review.googlesource.com/570485
Commit-Queue: Caitlin Potter <caitp@igalia.com>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46683}
78 files changed
tree: cdca1e325df1294e011e78d64708b41602460295
  1. benchmarks/
  2. build_overrides/
  3. docs/
  4. gni/
  5. gypfiles/
  6. include/
  7. infra/
  8. samples/
  9. src/
  10. test/
  11. testing/
  12. third_party/
  13. tools/
  14. .clang-format
  15. .gitignore
  16. .gn
  17. .ycm_extra_conf.py
  18. AUTHORS
  19. BUILD.gn
  20. ChangeLog
  21. CODE_OF_CONDUCT.md
  22. codereview.settings
  23. DEPS
  24. LICENSE
  25. LICENSE.fdlibm
  26. LICENSE.strongtalk
  27. LICENSE.v8
  28. LICENSE.valgrind
  29. Makefile
  30. Makefile.android
  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.