The new implementation is based on suspend/resume stubs and doesn't
use desugaring of async functions on kernel AST.
Previously, new implementation of async/async* was only supported in
AOT mode. This change adds all necessary bits for the JIT mode:
* Suspending variable-length frames (for unoptimized code).
* Handling of Code and pool pointers in Dart stack frames.
* OSR.
* Deoptimization.
* Hot reload.
* Debugger.
The new implementation is not enabled in JIT mode yet.
Design doc: go/compact-async-await.
TEST=ci
Issue: https://github.com/dart-lang/sdk/issues/48378
Change-Id: I477d6684bdce7cbc1edb179ae2271ff598b7dcc5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/246081
Reviewed-by: Martin Kustermann <kustermann@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
The new implementation moves away from desugaring of async
functions on kernel AST, state machine generated in the flow graph and
capturing all local variables in the context.
Instead, async/await is implemented using a few stubs
(InitSuspendableFunction, Suspend, Resume, Return and
AsyncExceptionHandler). The stubs are implemented in a
platform-independent way using (macro-)assembler helpers.
When suspending a function, its frame is copied into a SuspendState
object, and when resuming a function it is copied back onto the stack.
No extra code is generated for accessing local variables.
Callback closures are created lazily on the first await.
Design doc: go/compact-async-await.
Part 1 (kernel): https://dart-review.googlesource.com/c/sdk/+/241842
TEST=ci
Issue: https://github.com/dart-lang/sdk/issues/48378
Change-Id: Ibad757035b7cc438ebdff80b460728b1d3eff1f5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/242000
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
* This message should only be reported by the parser; the
error raised in the analyzer was strictly duplicate.
* This message theoretically used to mention "async*" or
"sync*" depending on the modifier that the function in
question listed. However, listing one modifier or the
other is a red herring, and may confuse the user; any
function declared with one or the other is a "generator",
and the error applies equally to a "generator" using one
or the other modifier.
Bug: https://github.com/dart-lang/sdk/issues/43665
Change-Id: I6ef1f5c055473170e7563222f6f0a6c56a4ad5f5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/210801
Commit-Queue: Samuel Rawlins <srawlins@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
While deserializing AOT snapshot, Code objects which do not contain
valuable information besides entry point and stack maps are discarded
and not allocated on the heap (they are replaced with
StubCode::UnknownDartCode()).
PC -> Code/CompressedStackMaps lookup is implemented using a separate
table (InstructionsTable).
Flutter gallery in release-sizeopt mode:
Heap size of snapshot objects: arm -26.89%, arm64 -27.68%
Large Flutter application in release mode with --dwarf-stack-traces:
Heap size of snapshot objects: -24.3%.
Discarded Code objects: 72.5% of all Code objects.
Issue: https://github.com/dart-lang/sdk/issues/44852.
TEST=existing tests; "--dwarf_stack_traces --no-retain_function_objects
--no-retain_code_objects" mode is enabled for a few tests.
Change-Id: I5fe3e283630c8e8f4442319d5dcae38d174dd0d8
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/189560
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
This converts `return e` in async methods in opt-in libraries into
return let v = e in v is Future<FTV> ? await v ; v
where FTV is the future value type of the enclosing function.
Closes#44395Closes#44396Closes#44397Closes#44399
TEST=existing tests
Change-Id: I59687039bfe4a97ffdaa55ac0f193ca4fb208f44
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/175310
Commit-Queue: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Erik Ernst <eernst@google.com>
The rules for returns with null-safety were changed in language PR #941,
and this PR makes changes to async/return_types_test.dart such that it
matches the new rules. Check base vs. patchset 1 to see these adjustments.
The main part of this PR is that it migrates and updates the tests
language/invalid_returns/{,a}sync_{,in}valid*_test.dart such
that they match the new rules. Check patchset 1 vs newest patchset
to see this migration.
Note that some tests are new, e.g., 'sync_invalid_return_27_test',
which was added because it is a new property that there is an error
for "return void to Null". Also note that some of the tests are
redundant: (1) It is no longer allowed to return void to Null, but
(2) that's an error already with null-safety, because it's a
downcast (so it doesn't matter which supertype of `Null` we have).
I kept these tests anyway (and even wrote this new one), because
they do check that certain changes have been implemented, even
though it is in some cases redundant in the sense that it's just
another verification that implicit downcasts aren't supported any
more. If we don't want this redundancy then we should remove about
10 tests (sync_invalid_return, async_invalid_return).
Change-Id: I3f10682e1d0ed75067d6e8651588b727ffd3648f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/145587
Commit-Queue: Erik Ernst <eernst@google.com>
Reviewed-by: Leaf Petersen <leafp@google.com>
Alexander Markov