[vm, gen_snapshot] Add app-aot-macho-dylib option for AOT snapshots.

This is the initial framework for creating snapshots as Mach-O dynamic
libraries. Note that this framework is not 100% feature complete
compared to generating Mach-O snapshots via assembly. In particular,
the directly-compiled Mach-O dylib does not yet contain compact
unwinding information.

Other changes:

* Adds UuidCommand to the native_stack_traces package's Mach-O reader,
  which now appropriately returns the UUID as the build ID for Mach-O
  shared objects.

* Adds Utils::Basename(path) for portably retrieving the basename
  from a path. (Returns nullptr for all arguments where it is not
  currently implemented on Fuchsia or Windows.)

* Adjusts vm/timeline.h to avoid pulling in <mach_o/loader.h> on MacOS,
  as that interferes with uses of the namespaced Mach-O definitions
  in platform/mach_o.h.

* Only attempt to dlopen() a snapshot if ELF is the native format
  for the host platform or the snapshot is not an ELF shared object.
  If dlopen() is used, report the error message if it fails rather
  than attempting to manually load the snapshot as an ELF shared object.

* Fix the magic number stored in DylibAppSnapshot for loaded non-ELF
  dynamic libraries.

* Remove the detection of reverse-endian Mach-O magic numbers in
  DartUtils::SniffForMagicNumber(), since all our Mach-O related code
  assumes host-endian Mach-O files and so there's no point other than
  to give a slightly better error message when failing.

TEST=vm/dart/exported_symbols_test
     vm/dart/unobfuscated_static_symbols_test
     vm/dart/use_dwarf_stack_traces_flag_test
     vm/cc/CanDetectMachOFiles

Issue: https://github.com/dart-lang/sdk/issues/60307
Change-Id: Idf5b49d6c6d035ab033509613212b95520d65965
Cq-Include-Trybots: luci.dart.try:vm-aot-linux-debug-x64-try,vm-mac-release-arm64-try,vm-aot-mac-release-arm64-try,vm-aot-mac-release-x64-try,vm-aot-dwarf-linux-product-x64-try,vm-linux-debug-x64-try,vm-mac-debug-arm64-try,vm-fuchsia-release-x64-try,vm-fuchsia-release-arm64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/415020
Reviewed-by: Slava Egorov <vegorov@google.com>
Commit-Queue: Tess Strickland <sstrickl@google.com>
37 files changed
tree: b92eb84f65a60b00898e70eae023c68532c4583d
  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. pubspec.yaml
  32. README.dart-sdk
  33. README.md
  34. sdk.code-workspace
  35. sdk_args.gni
  36. sdk_packages.yaml
  37. SECURITY.md
  38. 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.

  • 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 in our repo at docs.

Contributing to Dart

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

You can also contribute patches, as described in Contributing.

Roadmap

Future plans for Dart are included in the combined Dart and Flutter roadmap on the Flutter wiki.