[vm] Avoid creating unnecessary SafepointPosition's

Register allocator does not need to associate always-calls
safepoints with live ranges of constant values because
constant values are never actually spilled and are rematerialized
instead.

@alexmarkov has observed that SafepointPosition objects for
constants account for large chunk of the total memory eaten by
the register allocation pass and this change addresses this issue.

With this change the total memory consumed by the register allocator
decreases from 21 Gb to 8.6 Gb on one of the examples
in https://github.com/flutter/flutter/issues/94461.

TEST=ci

Change-Id: I245f2678bc6f5c1d63fd282812d1df2b2958512f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/231442
Auto-Submit: Slava Egorov <vegorov@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Slava Egorov <vegorov@google.com>
1 file changed
tree: bf55d27d0a06064bc400796deddf3426fa14d8a0
  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. compile_output.txt
  30. CONTRIBUTING.md
  31. DEPS
  32. LICENSE
  33. PATENT_GRANT
  34. PRESUBMIT.py
  35. README.dart-sdk
  36. README.md
  37. sdk_args.gni
  38. SECURITY.md
  39. 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

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See LICENSE and PATENT_GRANT.

Using Dart

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

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There are more documents on our wiki.

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