[dart2wasm] New async implementation This CL re-implements the async function compilation without using JSPI or any other platform features. This implementation is faster than the JSPI-based one in all benchmarks, in some cases up to 200x (benchmark results at the end). So we remove the JSPI-based implementation as there's no point in maintaining a much slower implementation and supporting two implementations at the same time (which is tricky because these implementations need different libraries, all scripts need to support two modes etc.) that also requires experimental platform features. # Main changes - A new pass `AwaitTransformer` transforms `await` expressions to top-level statements in form `var <fresh variable> = await <simple expr>`, where `<simple expr>` is an expression without `await`. After this pass all `await` expressions have the simple continuation of "assign the value of the awaited future to this variable and continue with the next statement". This simplifies `await` compilation. - A new code generator `AsyncCodeGenerator` (inherits from `CodeGenerator`) compiles `async` functions. The `_YieldFinder` class is copied from `sync*` code generator but modified to handle `async` expressions. - Mentions to the V8 flag `--experimental-wasm-stack-switching` is removed from all scripts and documents. # Future work - Control flow handling in `AsyncCodeGenerator` needs to be implemented in a similar way in `SyncStarCodeGenerator`. Doing this without duplicating a lot of code will require some refactoring. # New passing tests - co19/Language/Statements/Yield_and_Yield_Each/Yield/execution_async_A05_t01 - co19/Language/Statements/For/Asynchronous_For_in/execution_A02_t02 - language/regress/regress23996_test - language/sync_star/dcall_type_test # Benchmarks Current implementation: ``` AsyncLiveVars.LiveObj1(RunTime): 1586000.0 us. AsyncLiveVars.LiveObj2(RunTime): 2114000.0 us. AsyncLiveVars.LiveObj4(RunTime): 1972500.0 us. AsyncLiveVars.LiveObj8(RunTime): 2212000.0 us. AsyncLiveVars.LiveObj16(RunTime): 2238000.0 us. AsyncLiveVars.LiveInt1(RunTime): 2362000.0 us. AsyncLiveVars.LiveInt4(RunTime): 2470000.0 us. AsyncLiveVars.LiveObj2Int2(RunTime): 2575000.0 us. AsyncLiveVars.LiveObj4Int4(RunTime): 2820000.0 us. Calls.AwaitAsyncCall(RunTimeRaw): 35676.15658362989 ns. Calls.AwaitAsyncCallClosureTargetPolymorphic(RunTimeRaw): 38934.108527131786 ns. Calls.AwaitAsyncCallInstanceTargetPolymorphic(RunTimeRaw): 42617.02127659575 ns. Calls.AwaitFutureCall(RunTimeRaw): 2832.058906825262 ns. Calls.AwaitFutureCallClosureTargetPolymorphic(RunTimeRaw): 3665.8125915080527 ns. Calls.AwaitFutureCallInstanceTargetPolymorphic(RunTimeRaw): 4420.449537241076 ns. Calls.AwaitFutureOrCall(RunTimeRaw): 3692.7621861152143 ns. Calls.AwaitFutureOrCallClosureTargetPolymorphic(RunTimeRaw): 4625.346901017576 ns. Calls.AwaitFutureOrCallInstanceTargetPolymorphic(RunTimeRaw): 4514.6726862302485 ns. Calls.AwaitFutureOrCallInstanceTargetPolymorphicManyAwaits(RunTimeRaw): 345172.4137931034 ns. Calls.AwaitForAsyncStarStreamPolymorphic(RunTimeRaw): 697000.0 ns. Calls.AwaitForAsyncStarStreamPolymorphicManyYields(RunTimeRaw): 704666.6666666666 ns. Calls.AwaitForManualStreamPolymorphic(RunTimeRaw): 11010.989010989011 ns. Calls.SyncCall(RunTimeRaw): 0.40275240996973316 ns. Calls.SyncCallClosureTarget(RunTimeRaw): 0.3989591156672242 ns. Calls.SyncCallInstanceTargetPolymorphic(RunTimeRaw): 3.2632549336335526 ns. Calls.IterableSyncStarIterablePolymorphic(RunTimeRaw): 353.3980582524272 ns. Calls.IterableManualIterablePolymorphic(RunTimeRaw): 332.1161825726141 ns. Calls.IterableManualIterablePolymorphicManyYields(RunTimeRaw): 354.28067078552516 ns. ``` New implementation: ``` AsyncLiveVars.LiveObj1(RunTime): 11327.683615819209 us. AsyncLiveVars.LiveObj2(RunTime): 10923.91304347826 us. AsyncLiveVars.LiveObj4(RunTime): 10956.284153005465 us. AsyncLiveVars.LiveObj8(RunTime): 11286.516853932584 us. AsyncLiveVars.LiveObj16(RunTime): 11445.714285714286 us. AsyncLiveVars.LiveInt1(RunTime): 11016.483516483517 us. AsyncLiveVars.LiveInt4(RunTime): 11327.683615819209 us. AsyncLiveVars.LiveObj2Int2(RunTime): 10918.478260869566 us. AsyncLiveVars.LiveObj4Int4(RunTime): 10737.967914438503 us. Calls.AwaitAsyncCall(RunTimeRaw): 1082.2510822510822 ns. Calls.AwaitAsyncCallClosureTargetPolymorphic(RunTimeRaw): 1056.4124234100993 ns. Calls.AwaitAsyncCallInstanceTargetPolymorphic(RunTimeRaw): 1134.1726210729273 ns. Calls.AwaitFutureCall(RunTimeRaw): 865.6509695290858 ns. Calls.AwaitFutureCallClosureTargetPolymorphic(RunTimeRaw): 841.3967185527977 ns. Calls.AwaitFutureCallInstanceTargetPolymorphic(RunTimeRaw): 839.066957543212 ns. Calls.AwaitFutureOrCall(RunTimeRaw): 397.9941096871766 ns. Calls.AwaitFutureOrCallClosureTargetPolymorphic(RunTimeRaw): 406.17384240454913 ns. Calls.AwaitFutureOrCallInstanceTargetPolymorphic(RunTimeRaw): 393.7472929873607 ns. Calls.AwaitFutureOrCallInstanceTargetPolymorphicManyAwaits(RunTimeRaw): 1095.0503723171266 ns. Calls.AwaitForAsyncStarStreamPolymorphic(RunTimeRaw): 6643.426294820717 ns. Calls.AwaitForAsyncStarStreamPolymorphicManyYields(RunTimeRaw): 7178.750897343863 ns. Calls.AwaitForManualStreamPolymorphic(RunTimeRaw): 1456.23998835008 ns. Calls.SyncCall(RunTimeRaw): 0.3919935321067202 ns. Calls.SyncCallClosureTarget(RunTimeRaw): 0.3906669661780074 ns. Calls.SyncCallInstanceTargetPolymorphic(RunTimeRaw): 3.1676143112814583 ns. Calls.IterableSyncStarIterablePolymorphic(RunTimeRaw): 104.4932079414838 ns. Calls.IterableManualIterablePolymorphic(RunTimeRaw): 104.57516339869281 ns. Calls.IterableManualIterablePolymorphicManyYields(RunTimeRaw): 116.92487576731949 ns. ``` TEST=ci CoreLibraryReviewExempt: Added entry-point pragmas. Change-Id: I02fbd08141f51c00fb37b6fa0304dc25d6afdb71 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/301020 Commit-Queue: Ömer Ağacan <omersa@google.com> Reviewed-by: William Hesse <whesse@google.com> Reviewed-by: Johnni Winther <johnniwinther@google.com> Reviewed-by: Joshua Litt <joshualitt@google.com> https://dart.googlesource.com/sdk/+/c74387a3a29c6edefd8c423ba7025d298b5b45a0
Monorepo is:
With depot_tools installed and on your path, create a directory for your monorepo checkout and run these commands to create a gclient solution in that directory:
mkdir monorepo cd monorepo gclient config --unmanaged https://dart.googlesource.com/monorepo gclient sync -D
This gives you a checkout in the monorepo directory that contains:
monorepo/ DEPS - the DEPS used for this gclient checkout commits.json - the pinned commits for Dart, flutter/engine, and flutter/flutter tools/ - scripts used to create monorepo DEPS engine/src/ - the flutter/buildroot repo flutter/ - the flutter/engine repo out/ - the build directory, where Flutter engine builds are created third_party/ - Flutter dependencies checked out by DEPS dart/ - the Dart SDK checkout. third_party - Dart dependencies, also used by Flutter flutter/ - the flutter/flutter repo
Flutter's instructions for building the engine are at Compiling the engine
They can be followed closely, with a few changes:
goma_ctl ensure_start is sufficient.Example build commands that work on linux:
MONOREPO_PATH=$PWD if [[ ! $PATH =~ (^|:)$MONOREPO_PATH/flutter/bin(:|$) ]]; then PATH=$MONOREPO_PATH/flutter/bin:$PATH fi export GOMA_DIR=$(dirname $(command -v gclient))/.cipd_bin goma_ctl ensure_start pushd engine/src flutter/tools/gn --goma --no-prebuilt-dart-sdk --unoptimized --full-dart-sdk autoninja -C out/host_debug_unopt popd
The Flutter commands used to build and run apps will use the locally built Flutter engine and Dart SDK, instead of the one downloaded by the Flutter tool, if the --local-engine option is provided.
For example, to build and run the Flutter spinning square sample on the web platform,
MONOREPO_PATH=$PWD cd flutter/examples/layers flutter --local-engine=host_debug_unopt \ -d chrome run widgets/spinning_square.dart cd $MONOREPO_PATH
To build for desktop, specify the desktop platform device in flutter run as -d macos or -d linux or -d windows. You may also need to run the command
flutter create --platforms=windows,macos,linux
on existing apps, such as sample apps. New apps created with flutter create already include these support files. Details of desktop support are at Desktop Support for Flutter
Tests in the Flutter source tree can be run with the flutter test command, run in the directory of a package containing tests. For example:
MONOREPO_PATH=$PWD cd flutter/packages/flutter flutter test --local-engine=host_debug_unopt cd $MONOREPO_PATH
Please file an issue or email the dart-engprod team with any problems with or questions about using monorepo.
We will update this documentation to address them.
flutter commands may download the engine and Dart SDK files for the configured channel, even though they will be using the local engine and its SDK.gclient sync needs to be run in an administrator session, because some installed dependencies create symlinks.