commit	2c2910c3e4821732b7660e362fad1f413c2f7349	[log] [tgz]
author	Mitch Rudominer <rudominer@chromium.org>	Fri Mar 25 13:32:25 2016 -0700
committer	Mitch Rudominer <rudominer@chromium.org>	Fri Mar 25 13:32:25 2016 -0700
tree	f5716f920264d239c7936925171863398aa7682d
parent	9d8f1e9a9bbd486516f0a68b64c4219a89b0c4bf [diff]

Mojom backend: Stop re-computing version info and field packing data.

We have removed most of the logic from pack.py because these computations are now being performed
in the front end. What remains in pack.py is some logic to re-organize the data from the
intermediate representation into a form that the code generators want. As we start to build
new-generation backends we can re-visit the exact shape of the data we put into the
intermediate representation and perhaps some more of this reorganization logic might be
moved to the front end:
 - We left the PackedStruct object because this is what the code generators expect.
  It is mostly populated now by copying data from the intermediate representation.
 - We left the function GetByteLayout(). This function synthesizes the byte layout for a struct based on
equivalent data in the intermediate representation.
 - The utility function GetPad() seems to be used directly by some of the code generators.

Summary of changes:

- In pack.py we delete GetAlignmentForKind, GetFieldOffset, GetVersionInfo, and most of the logic in the PackedStruct
  constructor.

- We delete pack_tests.py and pack_unittest.py. These tests have been ported to Go tests in the frontend
  in https://codereview.chromium.org/1833593002/.

- In mojom_translator.py we translate the version_info field of a struct and the offset, bit and
  min_version fields of a struct field.

- In generator.py we stop creating synthetic request and response parameter structs and instead use
  the ones translated from the intermediate representation. Similarly we stop computing struct.versions.

- We modify the logic in mojom_go_generatory.py so that rather than constructing a new object
  to represent a synthetic parameter struct instead we use the object that has been translated
  from the intermediate representation, because that object contains the packing data.

- In module.py we eliminate the min_versions property getter because the min_version property is now
  part of the intermediate representation.

BUG=#713
R=azani@chromium.org

Review URL: https://codereview.chromium.org/1824263002 .

9 files changed

tree: f5716f920264d239c7936925171863398aa7682d

README.md

Mojo

Mojo is a collection of interprocess communication technologies, protocols and a runtime for creating applications and services that are composable while being loosely coupled. It simplifies the creation of fully asynchronous component-based systems and provides guarantees so that components made by different vendors and in different programming languages can interoperate.

Set-up and code check-out

The instructions below only need to be done once. Note that a simple “git clone” command is not sufficient to build the source code because this repo uses the gclient command from depot_tools to manage most third party dependencies.

Download depot_tools and make sure it is in your path.
[Googlers only] Install Goma in ~/goma.
Create a directory somewhere for your checkout (preferably on an SSD), cd into it, and run the following commands:

$ fetch mojo # append --target_os=android to include Android build support.
$ cd src

# Or install-build-deps-android.sh if you plan to build for Android.
$ ./build/install-build-deps.sh

$ mojo/tools/mojob.py gn

The fetch mojo command does the following:

creates a directory called ‘src’ under your checkout directory
clones the repository using git clone
clones dependencies with gclient sync

install-build-deps.sh installs any packages needed to build, then mojo/tools/mojob.py gn runs gn args and configures the build directory, out/Debug.

If the fetch command fails, you will need to delete the src directory and start over.

Adding Android bits in an existing checkout

If you configured your set-up for Linux and now wish to build for Android, edit the .gclient file in your root Mojo directory (the parent directory to src.) and add this line at the end of the file:

target_os = [u'android',u'linux']

Bring in Android-specific build dependencies:

$ build/install-build-deps-android.sh

Pull down all of the packages with this command:

$ gclient sync

Update your checkout

You can update your checkout like this. The order is important. You must do the git pull first because gclient sync is dependent on the current revision.

# Fetch changes from upstream and rebase the current branch on top
$ git pull --rebase
# Update all modules as directed by the DEPS file
$ gclient sync

You do not need to rerun gn gen out/Debug - ninja does so automatically each time you build. You might need to rerun mojo/tools/mojob.py gn if the GN flags have changed.

Build Mojo

Linux

Build Mojo for Linux by running:

$ ninja -C out/Debug -j 10

You can also use the mojob.py script for building. This script automatically calls ninja and sets -j to an appropriate value based on whether Goma (see the section on Goma below) is present. You cannot specify a target name with this script.

mojo/tools/mojob.py gn
mojo/tools/mojob.py build

Run a demo:

out/Debug/mojo_shell mojo:spinning_cube

Run the tests:

mojo/tools/mojob.py test

Run the benchmarks:

mojo/devtools/common/mojo_benchmark mojo/tools/data/benchmarks

Create a release build:

mojo/tools/mojob.py gn --release
mojo/tools/mojob.py build --release
mojo/tools/mojob.py test --release

Android

To build for Android, first make sure that your checkout is configured to build for Android. After that you can use the mojob script as follows:

$ mojo/tools/mojob.py gn --android
$ mojo/tools/mojob.py build --android

The result will be in out/android_Debug. If you see javac compile errors, make sure you have an up-to-date JDK

Goma (Googlers only)

If you're a Googler, you can use Goma, a distributed compiler service for open-source projects such as Chrome and Android. If Goma is installed in the default location (~/goma), it will work out-of-the-box with the mojob.py gn, mojob.py build workflow described above.

You can also manually add:

use_goma = true

at the end of the file opened through:

$ gn args out/Debug

After you close the editor gn gen out/Debug will run automatically. Now you can dramatically increase the number of parallel tasks:

$ ninja -C out/Debug -j 1000

Official builds

Official builds for android generate a signed Mojo Shell intended for distribution. You normally should not need to produce one. If you have any questions, reach out to etiennej@chromium.org.

Run Mojo Shell

Devtools mojo_run is a universal shell runner abstracting away the differences between running on Linux and Android.

Having built Mojo as described above, a demo app can be run as follows:

mojo/devtools/common/mojo_run https://core.mojoapps.io/spinning_cube.mojo  # Linux
mojo/devtools/common/mojo_run https://core.mojoapps.io/spinning_cube.mojo --android  # Android

Development server

Whenever mojo_run is run, a development server is set up according to the config file. The server runs on your machine, serving the locally built apps, but appears to the shell under the https://core.mojoapps.io host.

You can ignore the config file and skip spawning the local server (for example, in order to use apps at the actual https://core.mojoapps.io web host) by passing --no-config-file to mojo_run.

More examples

Some applications can be run directly from the source tree. The development server serves the src directory, allowing to refer to these apps. For instance, this command serves a dart Mojo app from the source at examples/dart/device_info/main.dart:

mojo/devtools/common/mojo_run https://core.mojoapps.io/examples/dart/device_info/lib/main.dart [--android]

Some applications implement ViewProvider and are run embedded in a view. To run these, you can pass the app url using the --embed flag:

mojo/devtools/common/mojo_run --embed mojo:moterm_example_app [--android]

which is a shorthand for:

mojo/devtools/common/mojo_run "mojo:launcher mojo:moterm_example_app"

For additional information on mojo_run refer to the built-in help and the documentation. You can also request more information on what the tool is doing for you by passing the --verbose flag.

Debugging, tracing, profiling

Devtools mojo_debug allows you to interactively inspect a running shell, collect performance traces and attach a gdb debugger.

For additional information refer to the built-in help and the documentation.

Android set-up

Adb

For the Android tooling to work, you will need to have adb in your PATH. For that, you can either run:

source build/android/envsetup.sh

each time you open a fresh terminal, or add something like:

export PATH="$PATH":$MOJO_DIR/src/third_party/android_tools/sdk/platform-tools

to your ~/.bashrc file, $MOJO_DIR being a path to your Mojo checkout.

Device

The device has to be running Android 5.0 (Lollipop) or newer.

Many features useful for development (ie. streaming of the shell stdout when running shell on the device) will not work unless the device is rooted and running a userdebug build. For Googlers, follow the instructions at this link.

Running manually on Linux

If you wish to, you can also run the Linux Mojo shell directly with no wrappers:

./out/Debug/mojo_shell out/Debug/spinning_cube.mojo

Contribute

With git you should make all your changes in a local branch. Once your change is committed, you can delete this branch.

Create a local branch named “mywork” and make changes to it.

  cd src
  git new-branch mywork
  vi ...

Commit your change locally. (this doesn't commit your change to the SVN or Git server)

  git commit -a

Fix your source code formatting.

$ git cl format

Upload your change for review.

$ git cl upload

Respond to review comments.

See Contributing code for more detailed git instructions, including how to update your CL when you get review comments. There's a short tutorial that might be helpful to try before making your first change: C++ in Chromium 101.

To land a change after receiving LGTM:

$ git cl land

Monitoring

Our waterfall continuously builds and tests the code. Don't break the build!

Benchmarks

One of the bots, Mojo Linux Perf runs a suite of benchmarks and uploads the results to the performance dashboard. You can browse the results here, putting mojo_benchmarks as the “test suite”.

Automated alerts about performance regressions are sent to mojo-perf-alerts@chromium.org.

For examples of interesting sets of graphs see: