[vm/ffi] Stop writing beyond allocated stack space

This CL adds an assert to check we're not writing beyond the allocated
stack space. This assert triggers at compile-time, rather than at
runtime, and it catches cases which would sometimes go correct at
runtime because the stack is also 16-byte aligned.

This only occurred on MacOS/iOS Arm64 because structs are word-aligned
on the stack in the other ABIs.

The fix in this CL is to always add 4 bytes extra in this ABI.

The alternative fix would be to stop copying word-size chunks and use
smaller moves. However, this would require a major re-engineering of
the marshaller because it breaks structs up in word-size definitions
currently.

TEST=tests/ffi/function_structs_by_value_generated_test.dart
     (would trigger the assert without the fix on MacOS arm64)

Fixed: https://github.com/dart-lang/sdk/issues/48806
Change-Id: Ia590be76919a192fed144520ee28b1abaf3aa485
Cq-Include-Trybots: luci.dart.try:vm-kernel-nnbd-mac-debug-arm64-try,vm-kernel-nnbd-mac-debug-x64-try,dart-sdk-mac-arm64-try,vm-kernel-linux-debug-ia32-try,vm-kernel-win-debug-ia32-try,vm-kernel-win-debug-x64-try,vm-kernel-linux-debug-x64-try,vm-kernel-linux-debug-x64c-try,vm-precomp-ffi-qemu-linux-release-arm-try,vm-ffi-android-debug-arm-try,vm-ffi-android-debug-arm64c-try,vm-kernel-precomp-android-release-arm_x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/241607
Reviewed-by: Clement Skau <cskau@google.com>
Reviewed-by: Aske Simon Christensen <askesc@google.com>
Commit-Queue: Daco Harkes <dacoharkes@google.com>
2 files changed
tree: de1df3edfa3fb591c20de95107f47f8575410da8
  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. .style.yapf
  23. .vpython
  24. AUTHORS
  25. BUILD.gn
  26. CHANGELOG.md
  27. codereview.settings
  28. CONTRIBUTING.md
  29. DEPS
  30. LICENSE
  31. OWNERS
  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.