[vm/compiler] Improve flow sensitivity of CP

Before running CP find all branches of form `Branch(v eq C)`,
where `eq` is one of `===`, `==`, `!==` or `!=` and `C` is
a constant and insert a redefinition of `v` in the true
successor which captures the information that `v` is equal
to `C` guaranteed by the branch.

SCCP algorithm can then use this information when propagating
constants. After SCCP all redefinitions inserted are removed
again.

We don't actually replace `v` with `C` in the dominated code
because this might lead to issues later, for example
it might result in redundant phis `phi(C, v)` (`C` flowing
from a predecessor where `v == C`) which are complicated
to eliminate again.

TEST=vm/dart/comparison_canonicalization_il_test

Cq-Include-Trybots: luci.dart.try:vm-aot-linux-release-x64-try,vm-aot-linux-debug-simarm_x64-try,vm-aot-linux-debug-x64-try,vm-aot-android-release-arm64c-try
Change-Id: I388dddb97b5e35f09d9904000c585864f27400f6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/324980
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Slava Egorov <vegorov@google.com>
7 files changed
tree: 417e011b218890aeb24a3947f5f11cc41990d222
  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. .vpython
  22. AUTHORS
  23. BUILD.gn
  24. CHANGELOG.md
  25. codereview.settings
  26. CONTRIBUTING.md
  27. DEPS
  28. LICENSE
  29. OWNERS
  30. PATENT_GRANT
  31. PRESUBMIT.py
  32. README.dart-sdk
  33. README.md
  34. sdk.code-workspace
  35. sdk_args.gni
  36. SECURITY.md
  37. WATCHLISTS
README.md

Dart

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

License & patents

Dart is free and open source.

See LICENSE and PATENT_GRANT.

Using Dart

Visit dart.dev to learn more about the language, tools, and to find codelabs.

Browse pub.dev for more packages and libraries contributed by the community and the Dart team.

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Building Dart

If you want to build Dart yourself, here is a guide to getting the source, preparing your machine to build the SDK, and building.

There are more documents on our wiki.

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The easiest way to contribute to Dart is to file issues.

You can also contribute patches, as described in Contributing.