[pkg/dart2native] Add negative padding check to MachO writer.

This catches an inadvertent partial overwrite of the first section
in the `dartaotruntime` executable that happens when there's not
enough padding after the headers. The first section is a text section,
so unless there are no calls to code in this overwritten portion, there
are no runtime failures when this happens.

However, having a MachO section which has a file offset within the
headers is checked by MachO verification code within the `codesign`
utility when run with the `-f` flag, and thus caused failures in
certain tests and builds. Note that we only use that flag when
`codesign` does not have the `linker-signed` option, which is for
MacOS versions prior to 12.0.

Example failure with this change when this case occurs (e.g., prior to
the recent clang revert):
```
$ xcodebuild/ReleaseARM64/dart-sdk/bin/dart compile exe -o test test.dart
Info: Compiling with sound null safety
Error: AOT compilation failed
FormatException: The MachO header overlaps with the first 120 bytes of the section contents
```

Change-Id: Ib27db910777f61b90f162f7a0bcfa4ba6592a5a0
Bug: https://github.com/dart-lang/sdk/issues/49783
Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-nnbd-mac-release-arm64-try,vm-kernel-precomp-mac-product-x64-try,dart-sdk-mac-arm64-try,dart-sdk-mac-try,pkg-mac-release-arm64-try,pkg-mac-release-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/256264
Reviewed-by: Daco Harkes <dacoharkes@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Tess Strickland <sstrickl@google.com>
1 file changed
tree: 9b4cf7bfd64dd713055628807fad11074526c573
  1. .dart_tool/
  2. .github/
  3. benchmarks/
  4. build/
  5. docs/
  6. pkg/
  7. runtime/
  8. samples/
  9. samples-dev/
  10. sdk/
  11. tests/
  12. third_party/
  13. tools/
  14. utils/
  15. .clang-format
  16. .gitattributes
  17. .gitconfig
  18. .gitignore
  19. .gn
  20. .mailmap
  21. .style.yapf
  22. .vpython
  23. AUTHORS
  24. BUILD.gn
  25. CHANGELOG.md
  26. codereview.settings
  27. CONTRIBUTING.md
  28. DEPS
  29. LICENSE
  30. OWNERS
  31. PATENT_GRANT
  32. PRESUBMIT.py
  33. README.dart-sdk
  34. README.md
  35. sdk_args.gni
  36. SECURITY.md
  37. 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.