[dart2wasm] Record type related cleanups

* avoid allocating _RecordType objects for `<obj> is/as <record-type>`
  => Introduce `Record._checkRecordType()`
  => Use `Record._recordRuntimeType` (which is now not masquerading) for
  other purposes (e.g. verification)

* avoid using masqueraded types for `<obj> is/as <record-type>`
  => Introduce `Record._masqueradedRecordRuntimeType`

Although we introduce 2 extra methods on `Record` that are overriden,
it's O(record-shapes-in-program) and therefore not a big overhead.

=> This will enforce the invariant that the actual type check
   implementation (i.e. for `<obj> is/as <type>` or
   for `<type> <: <type>`) *never* calls back into
   masquerading functionality

=> This in return means we can make the masquerading functionality
   using `<obj> is <type>` checks.

Change-Id: I3e3a0411022042a8e735aaeed396cc8f90d8c9c5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/349800
Reviewed-by: Slava Egorov <vegorov@google.com>
4 files changed
tree: abb765ad41bb1661b6d52c1ad0d3a1f679786e2d
  1. .dart_tool/
  2. .github/
  3. benchmarks/
  4. build/
  5. docs/
  6. pkg/
  7. runtime/
  8. samples/
  9. sdk/
  10. tests/
  11. third_party/
  12. tools/
  13. utils/
  14. .clang-format
  15. .gitattributes
  16. .gitconfig
  17. .gitignore
  18. .gn
  19. .mailmap
  20. .style.yapf
  21. AUTHORS
  22. BUILD.gn
  23. CHANGELOG.md
  24. codereview.settings
  25. CONTRIBUTING.md
  26. DEPS
  27. LICENSE
  28. OWNERS
  29. PATENT_GRANT
  30. PRESUBMIT.py
  31. README.dart-sdk
  32. README.md
  33. sdk.code-workspace
  34. sdk_args.gni
  35. SECURITY.md
  36. WATCHLISTS
README.md

Dart

An approachable, portable, and productive language for high-quality apps on any platform

Dart is:

  • Approachable: Develop with a strongly typed programming language that is consistent, concise, and offers modern language features like null safety and patterns.

  • Portable: Compile to ARM, x64, or RISC-V machine code for mobile, desktop, and backend. Compile to JavaScript or WebAssembly for the web.

  • Productive: Make changes iteratively: use hot reload to see the result instantly in your running app. Diagnose app issues using DevTools.

Dart's flexible compiler technology lets you run Dart code in different ways, depending on your target platform and goals:

  • Dart Native: For programs targeting devices (mobile, desktop, server, and more), Dart Native includes both a Dart VM with JIT (just-in-time) compilation and an AOT (ahead-of-time) compiler for producing machine code.

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Dart platforms illustration

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