[vm] Introduce --target-unknown-cpu option and use it for app-jit snapshots

App-jit and core-jit snapshots generated on one machine can be copied to
another machine with different CPU family/model, so it is incorrect to
use CPU features of the host machine to generate code for snapshots.

This change adds --target-unknown-cpu option and enables it when
generating app-jit and core-jit snapshots in standalone Dart VM and
gen_snapshot.

Currently, this flag disables SSE4.1, popcnt and ABM on ia32 and x64,
and integer division instruction on ARM. Also, new flag enables
testing of roundsd instruction availability at run time on x64
(similarly to AOT).

TEST=ci
Fixes https://github.com/dart-lang/sdk/issues/47907
Fixes https://github.com/flutter/flutter/issues/94181

Change-Id: Id28448052a21df4bae30b39e62b8532e55d4c901
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/223960
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
10 files changed
tree: f46c7940a6cb6592154cc9a7d7f88bc4857b878a
  1. .dart_tool/
  2. .github/
  3. benchmarks/
  4. build/
  5. docs/
  6. pkg/
  7. runtime/
  8. samples/
  9. samples-dev/
  10. samples_2/
  11. sdk/
  12. tests/
  13. third_party/
  14. tools/
  15. utils/
  16. .clang-format
  17. .gitattributes
  18. .gitconfig
  19. .gitignore
  20. .gn
  21. .mailmap
  22. .packages
  23. .style.yapf
  24. .vpython
  25. AUTHORS
  26. BUILD.gn
  27. CHANGELOG.md
  28. codereview.settings
  29. CONTRIBUTING.md
  30. DEPS
  31. LICENSE
  32. PATENT_GRANT
  33. PRESUBMIT.py
  34. README.dart-sdk
  35. README.md
  36. sdk_args.gni
  37. SECURITY.md
  38. 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.

Our API reference documentation is published at api.dart.dev, based on the stable release. (We also publish docs from our beta and dev channels, as well as from the primary development branch).

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.

Contributing to Dart

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

You can also contribute patches, as described in Contributing.