[vm/aot/tfa] Use RTA to improve AOT compilation speed

This change introduces Rapid Type Analysis (RTA) and uses it to
calculate initial set of allocated classes for Type Flow Analysis (TFA).
As a result, TFA converges much faster and AOT compilation time

RTA is less precise than TFA, so the set of allocated classes is
larger compared to the one calculated by TFA. However, it has only
marginal effect on the size of resulting AOT snapshots.

Time of AOT compilation step 2 on a large Flutter application
118.652s -> 59.907s (-49.5% / improved by a factor of 1.98x)
Snapshot size on armv8: -0.13%

Flutter gallery snapshot size in release and release-sizeopt modes
armv7 +0.19%, armv8 +0.2%

Just in case, RTA can be disabled using --no-rta option.

Issue: https://github.com/dart-lang/sdk/issues/42442
Issue: b/154155290

Change-Id: Iffbdabe7d486cad2e138f7592bffcb70474ddc34
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/222500
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
9 files changed
tree: 0822f7561d76de2823507442a76e48ec8c2fb514
  1. .dart_tool/
  2. .github/
  3. benchmarks/
  4. build/
  5. client/
  6. docs/
  7. pkg/
  8. runtime/
  9. samples/
  10. samples-dev/
  11. samples_2/
  12. sdk/
  13. tests/
  14. third_party/
  15. tools/
  16. utils/
  17. .clang-format
  18. .gitattributes
  19. .gitconfig
  20. .gitignore
  21. .gn
  22. .mailmap
  23. .packages
  24. .style.yapf
  25. .vpython
  27. BUILD.gn
  28. CHANGELOG.md
  29. codereview.settings
  31. DEPS
  34. PRESUBMIT.py
  35. README.dart-sdk
  36. README.md
  37. sdk_args.gni
  38. SECURITY.md


A client-optimized language for fast apps on any platform

Dart is:

  • Optimized for UI: Develop with a programming language specialized around the needs of user interface creation.

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

  • Fast on all platforms: Compile to ARM & x64 machine code for mobile, desktop, and backend. Or compile to JavaScript for the web.

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.

  • Dart Web: For programs targeting the web, Dart Web includes both a development time compiler (dartdevc) and a production time compiler (dart2js).

Dart platforms illustration

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