Visitor plugin sample

This plugin allows to count the number of postfix operations (either <expr>++ or <expr>--) that exist in the code by visiting the internal representation of every method. That number is then reported to the user.

This plugin introduces the following concepts of Jack:

• Plugin
• Schedulables
• Marker
• Feature
• Visitor
• User message reporting

Fetch the code

This plugin is hosted in the Jack development branch in AOSP. You can follow the instructions at http://source.android.com/source/downloading.html to setup your machine then execute the following commands

mkdir <jack_project_dir>
cd <jack_project_dir>
repo init -u https://android.googlesource.com/platform/manifest -b ub-jack
repo sync

where <jack_project_dir> is the directory where you want to download the Jack repository.

Build the plugin

First you need to initialize the plugin's local dependencies with the following commands

cd toolchain/jack
ant dist
cd jack-samples
ant

Then you can build the plugin using Gradle with the following commands

cd jack-visitor-plugin
./gradlew

The plugin .jar file is located at build/libs/jack-visitor-plugin.jar.

Execute the plugin

The plugin's name is com.android.jack.sample.countervisitor.CounterVisitorPlugin. Here is an example of command-line to compile source files with this plugin.

java -jar dist/jack.jar
 --pluginpath jack-samples/jack-visitor-plugin/build/libs/jack-visitor-plugin.jar
 --plugin com.android.jack.sample.countervisitor.CounterVisitorPlugin
 --verbose info --output-dex=<dex_dir> <source_files>

where <dex_dir> is the directory where the classes.dex file is generated and <source_files> are the source files to be compiled.

You can take a look at the Jack's command-line usage with

java -jar dist/jack.jar --help