Call sites targeting a procedure annotated with `external-effect` will not produce any code, including the argument which will not be evaluated. However, the single parameter will be treated as 'live' for the purposes of any global analysis the backends do. This is useful for things like protobuf shaking where a user may want to retain certain protobuf messages without actually emitting the code that retains those messages. Today this functionality is available internally in the vm and wasm SDK libraries. dart2js has similar functionality represented via the opaqueTrue and opaqueFalse booleans (which will cause conditional branches to get shaken after analysis). This will replace dart2js's opaque(True/False). This also adds validation to the frontend to ensure a method annotated with 'external-effect' is well-formed. Change-Id: If1c4096673e655c58fe7638840a16125003e7809 Tested: Backend tests for codegen were added. A frontend test was added for the validation. A language test was added to confirm the behavior. Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/476020 Reviewed-by: Alexander Markov <alexmarkov@google.com> Commit-Queue: Nate Biggs <natebiggs@google.com>
Dart Kernel
Dart Kernel is a small high-level language derived from Dart. It is designed for use as an intermediate format for whole-program analysis and transformations, and to be consumed by codegen and execution backends.
The kernel language has an in-memory representation in Dart and can be serialized as binary or text.
Both the kernel language and its implementations are unstable and are under development.
This package contains the Dart part of the implementation and contains:
- A transformable IR for the kernel language
- Serialization of kernel code
Note: The APIs in this package are in an early state; developers should be careful about depending on this package. In particular, there is no semver contract for release versions of this package. Please depend directly on individual versions.
See ast.dart for the in-memory IR, or binary.md for a description of the binary format. For now, the textual format is very ad-hoc and cannot be parsed back in.