[dart2wasm] Switch binaryen optimization levels from -O3 to -Os

We want dart2wasm be comparable to dart2js / dart2aot, the ladder two
are much more conservative with inlining compared to current dart2wasm.

The -O3 is described in the binaryen sources as agressive for
performance and therefore willing to compromise code size.

The -Os is more nuanced: It will perform many optimizations that are
done in -O3 (and e.g. not in -O2) but it will make inlining less
agressive.

This reduces flute compile-time by 10% and code size by 10%
This benchmark results are mixed (some things get faster, some things
slower). Naturally there'll be specialized micro benchmarks that
get hit hard by this.

Where performance matters we should rather make dart2wasm use better
inlining heuristics and annotate code with
`@pragma('wasm:prefer-inline')`

Change-Id: Idf7e75e4e385629c9cec66359efe0afe50db3e72
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/352523
Reviewed-by: Slava Egorov <vegorov@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
14 files changed
tree: 4938ddb8c1fa946ecd31c16c77d20d6ac155f399
  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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