[Class] Fix debug scope iteration for class fields

When trying to print the scope information for the class fields
initializer function, the debugger asks the parser to parse the class
literal as a function literal (to get the scope info) ... which
doesn't quite work.

Instead of adding support for parsing the class literal, we just short
cicruit this parsing step by just returning an empty context.

This works fine because initializer function doesn't have any
variables in it's local scope.

The one caveat is that the objects in the scope above this function
(like the global) are now missing. This trade off is possibly fine
for now, as adding parsing support for class literal to only produce
would be a lot of code for not enough use.

As a follow up to this change, the devtools UI needs to be updated to
handle this empty context cleanly. Currently, it doesn't show the
`this` object if no context exists even if the `this` object is
correctly passed to the UI from the backend.

Bug: v8:5367, v8:8122
Cq-Include-Trybots: luci.chromium.try:linux_chromium_headless_rel;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I52965f26241bbf6abdc988783aa0fc44bb36901f
Reviewed-on: https://chromium-review.googlesource.com/c/1274268
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56611}
3 files changed
tree: d54a0217e58bfb2d070a322b9c095dc549087e4d
  1. benchmarks/
  2. build_overrides/
  3. custom_deps/
  4. docs/
  5. gni/
  6. include/
  7. infra/
  8. samples/
  9. src/
  10. test/
  11. testing/
  12. third_party/
  13. tools/
  14. .clang-format
  15. .clang-tidy
  16. .editorconfig
  17. .git-blame-ignore-revs
  18. .gitattributes
  19. .gitignore
  20. .gn
  21. .vpython
  22. .ycm_extra_conf.py
  23. AUTHORS
  24. BUILD.gn
  25. ChangeLog
  26. CODE_OF_CONDUCT.md
  27. codereview.settings
  28. DEPS
  29. LICENSE
  30. LICENSE.fdlibm
  31. LICENSE.strongtalk
  32. LICENSE.v8
  33. LICENSE.valgrind
  34. OWNERS
  35. PRESUBMIT.py
  36. README.md
  37. snapshot_toolchain.gni
  38. 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.