Updates compiler.dart to use the new async transformation.
Some key things to note:
- Dart Let and BlockExpression expressions are represented as IIFEs in DDC compiled code. For non-async code this works fine but this doesn't work when they contain "await" expressions. When these expressions contain awaits we use the same lowering as we would for an async function, but instead apply it to the IIFE function. Then we simply await the IIFE Call expression as the IIFE will return a future after the transform.
- For async/sync*/async* functions we want to make sure parameter initialization happens synchronously before any of the async logic is hit. To do this we first apply the async transform the user-code function body. We then prepend the paramter initialization logic to the body of the transformed function.
- We add support for JS_RAW_EXCEPTION which allows the machinery in async_patch to access the wrapped JS exception in a catch block rather than the unwrapped Dart exception.
- Stacktraces and sourcemaps have some differences. There is still room for improvement in these but they should at least allow users to reasonably step through parts of the async code.
There are also several test fixes/updates associated with this change. The test_runner wrapper no longer has to inject in asyncStart/asyncEnd calls, these are handled by the new async logic.
Change-Id: I0f9f547cd9eb52ff7d850d277876d4d57568a14e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/374444
Reviewed-by: Bob Nystrom <rnystrom@google.com>
Reviewed-by: Mark Zhou <markzipan@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Nicholas Shahan <nshahan@google.com>
Nate Biggs
d84f908641