[dart2wasm] Modify wasm_builder to support multi-module deferred loading (1/2). None of these changes modify the generated wasm in any way yet. But all these changes allow dart2wasm to generate multiple modules to implement deferred loading and eventually dynamic modules. 1) Exposes tag export functionality. This functionality is supported by the exception handling spec/proposal but just wasn't added to wasm_builder originally: https://github.com/WebAssembly/exception-handling/blob/main/proposals/exception-handling/Exceptions.md The exception tag needs to be exported from the main module and then imported into subsequent modules so that exception handling works in a multi-module environment. 2) Support updates to imported tables via the element section. The element section provides an easy way to assign functions to indices in a table. This assignment can be applied to either a defined table or an imported table. wasm_builder only supported tracking element assignments for defined tables but deferred loading will make use of imported tables to which we will also want to assign functions. Change-Id: If23fbbb1e60a67d80d11924aaa718c50e68ecb98 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/378840 Reviewed-by: Martin Kustermann <kustermann@google.com> Reviewed-by: Ömer Ağacan <omersa@google.com> https://dart.googlesource.com/sdk/+/1e3fb80199d5605cb356ca45b09937c5df20246c
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.