[class] support out-of-scope private member access in debug-evaluate

Previously in the DevTools console, users could inspect a preview of all private class members on an instance, but if they wanted to evaluate or inspect a  specific private class member out of a long list, they had to be debugging and in a scope that has access to those private names.

This patch adds support for extraordinary access of out-of-scope private member access in debug-evaluate, specifically for Debugger.evaluateOnCallframe() (for console calls invoked during debugging) and Runtime.evaluate() (for console calls invoked when the user is not debugging). This kind of access is not otherwise allowed in normal execution, but in the DevTools console it makes sense to relax the rules a bit for a better developer experience.

To support this kind of extraordinary access, if the parsing_while_debugging or is_repl_mode flag is set, when we encounter a private name reference that's in a top-level scope or an eval scope under a top-level scope, instead of throwing immediately, we bind the reference to a dynamic lookup variable, and emit bytecode that calls to %GetPrivateName() or %SetPrivateName() in the runtime to perform lookup of the private name as well as the load/store operations accordingly.

If there are more than on private name on the receiver matching the description (for example, an object with two `#field` private names from different classes), we throw an error for the ambiguity (we can consider supporting selection among the conflicting private names later, for the initial support we just throw for simplicity).

If there are no matching private names, or if the found private class member does not support the desired operation (e.g. attempting to write to a read-only private accessor), we throw an error as well.

If there is exactly one matching private name, and the found private class member support the desired operation, we dispatch to the proper behavior in the runtime calls.

Doc: https://docs.google.com/document/d/1Va89BKHjCDs9RccDWhuZBb6LyRMAd6BXM3-p25oHd8I/edit

Bug: chromium:1381806
Change-Id: I7d1db709470246050d2e4c2a85b2292e63c01fe9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4020267
Commit-Queue: Joyee Cheung <joyee@igalia.com>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/main@{#85421}
31 files changed
tree: 0df032b676cd06651c54f53e956ed1dc396c591a
  1. .github/
  2. bazel/
  3. build_overrides/
  4. custom_deps/
  5. docs/
  6. gni/
  7. include/
  8. infra/
  9. samples/
  10. src/
  11. test/
  12. testing/
  13. third_party/
  14. tools/
  15. .bazelrc
  16. .clang-format
  17. .clang-tidy
  18. .editorconfig
  19. .flake8
  20. .git-blame-ignore-revs
  21. .gitattributes
  22. .gitignore
  23. .gn
  24. .mailmap
  25. .style.yapf
  26. .vpython3
  27. .ycm_extra_conf.py
  28. AUTHORS
  29. BUILD.bazel
  30. BUILD.gn
  31. CODE_OF_CONDUCT.md
  32. codereview.settings
  33. COMMON_OWNERS
  34. DEPS
  35. DIR_METADATA
  36. ENG_REVIEW_OWNERS
  37. INFRA_OWNERS
  38. INTL_OWNERS
  39. LICENSE
  40. LICENSE.fdlibm
  41. LICENSE.strongtalk
  42. LICENSE.v8
  43. LOONG_OWNERS
  44. MIPS_OWNERS
  45. OWNERS
  46. PPC_OWNERS
  47. PRESUBMIT.py
  48. README.md
  49. RISCV_OWNERS
  50. S390_OWNERS
  51. WATCHLISTS
  52. WORKSPACE
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://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/*

Contributing

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