Paul Berry
9b294b846b
This enables the front end to skip the old-style (enum-based) exhaustiveness checking algorithm when pattern support is enabled, because with pattern support enabled, switches on enums are required to be exhaustive (this will be checked by the new exhaustiveness checking algorithm). That in turn means that in the future, when we remove support for language versions that lack patterns support, we will be able to remove the old-style exhaustiveness checking algorithm. This change has a small effect on code generated by the WASM back-end (the only back-end that uses `isExplicitlyExhaustive`): for a switch statement that is exhaustive *and* has an unreachable `default` clause, after testing all the cases, the WASM back-end will generate a branch to the `default` case. Previously it would instead generate an `unreachable` instruction. There should be no behavioural difference because the instruction in question is unreachable in both cases. Also, there should be negligible code size difference because the body of the `default` case is being emitted either way. Bug: https://github.com/dart-lang/sdk/issues/50419 Change-Id: Id6bd7d9a540cb1b4d9c3624db8ff494438276bea Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/274924 Reviewed-by: Aske Simon Christensen <askesc@google.com> Commit-Queue: Paul Berry <paulberry@google.com> Reviewed-by: Johnni Winther <johnniwinther@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.