[ast] Always visit all AST nodes, even dead nodes

We'll let the bytecode compiler and optimizing compilers deal with dead code,
rather than the ast visitors. The problem is that the visitors previously
disagreed upon what was dead. That's bad if necessary visitors omit parts of
the code that the bytecode generator will actually visit.

I did consider removing the AST nodes immediately in the parser, but that
adds overhead and actually broke code coverage. Since dead code shouldn't be
shipped to the browser anyway (and we can still omit it later in the bytecode
generator), I opted for keeping the nodes instead.

Change-Id: Ib02fa9031b17556d2e1d46af6648356486f8433d
Reviewed-on: https://chromium-review.googlesource.com/c/1470108
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59569}
5 files changed
tree: ef80899d9393cd6811138cd610d33aa04015b957
  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. ChangeLog
  14. DEPS
  15. LICENSE
  16. LICENSE.fdlibm
  17. LICENSE.strongtalk
  18. LICENSE.v8
  19. LICENSE.valgrind
  20. OWNERS
  21. PRESUBMIT.py
  22. README.md
  23. WATCHLISTS
  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/
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.