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Faster parallel MXMLC compilation using Ant

February 9, 2010

Home » Faster parallel MXMLC compilation using Ant

Whenever you have a Flex project consisting of several modules, you can take advantage of compiling those modules in parallel – provided that they don’t depend on each other – using Ant and the Ant-Contrib tasks. In a project with five modules, I’ve seen a speed increase of about 30% compared to normal sequential compilation. I haven’t tested yet how this setup performs with more modules but I guess you could run into memory problems when compiling too many of them in parallel (you could still compile them in batches then). Below is part of an Ant script which does the job…here a few notes:

• At the top, the Ant-Contrib tasks are included. They provide a few useful tasks Ant doesn’t support out of the box, for example for-loops…
• The second section sets up a fileset which is used to declare all source files and later check if anything has changed and needs recompilation.
• The third section is where a single module is compiled using a macrodef task. If you haven’t used macrodef yet: It allows you to define kind of a general template for a custom task and substitute certain attributes or elements when you call the task (very useful!). The incremental option instructs mxmlc to generate cache files for faster recompilation. This example only toggles the incremental and debug options on when you compile for debugging. Additionally, the task checks if the source-files have changed and only then mxmlc will be started…
• The fourth section is where the actual parallel compilation of all modules happens: The for-task loops over a comma-separated list of modules (you could also dynamically generate this list depending on your folder structure) and compiles all modules (more or less) at the same time since the parallel flag is set to true. Before the compilation of all modules, the main file of the application is compiled. This can be useful if you want to generate a link-report based on your main application classes which is then fed into your module compilations with the load-externs option. Be careful not to use any operations in the for-loop which depend on the order of execution because things can get messed up when the parallel attribute is set.
• The last section simply calls the compile-all task with the debug flag set to true.

Of course, you can also run this script on a CI-Server but if you want to use the IDE for parallel compilation: IntelliJ, for example, will support parallel compilation in the next update. Another way to speed things up is the HFCD compiler which I haven’t tried yet…

Here’s the Ant snippet (left out the property definitions):

<taskdef resource="net/sf/antcontrib/antlib.xml">
    <classpath>
        <pathelement location="libs/ant/ant-contrib-1.0b3.jar"/>
    </classpath>
</taskdef>
 
<fileset id="flex.source.files" dir="${flex.source.dir}">
    <include name="**/*.as"/>
    <include name="**/*.mxml"/>
    <include name="**/*.css"/>
</fileset>
 
<macrodef name="compile-app">
    <attribute name="debug" default="true"/>
    <attribute name="appName"/>
    <sequential>
        <outofdate>
            <sourcefiles>
                <fileset refid="flex.source.files"/>
            </sourcefiles>
            <targetfiles path="${flex.release.dir}/@{appName}.swf"/>
            <sequential>
                <java jar="${flex.sdk.dir}/lib/mxmlc.jar" fork="true" failonerror="true">
                    <arg value="-debug=@{debug}"/>
                    <arg value="-incremental=@{debug}"/>
                    <!-- rest of mxmlc options -->
                </java>
            </sequential>
        </outofdate>
    </sequential>
</macrodef>
 
<macrodef name="compile-all">
    <attribute name="debug" default="true"/>
    <sequential>
        <compile-app appName="main" debug="@{debug}"/>
        <for list="${flex.modules}" param="module.name" parallel="true">
            <sequential>
                <compile-app appName="@{module.name}" debug="@{debug}"/>
            </sequential>
        </for>
    </sequential>
</macrodef>
 
<target name="compile-all-debug">
    <compile-all debug="true"/>
</target>

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