Building the ART Module

ART is built as a module in the form of an APEX package, com.android.art.apex. That package can be installed with adb install on a device running Android S or later. It is also included in the system partition (in the system/apex directory) of platform releases, to ensure it is always available.

The recommended way to build the ART Module is to use the master-art manifest, which only has the sources and dependencies required for the module.

The ART Module is available as a debug variant, com.android.art.debug.apex, which has extra internal consistency checks enabled, and some debug tools. A device cannot have both the non-debug and debug variants installed at once - it may not boot then.

com.google.android.art.apex (note .google.) is the Google signed variant of the module. It is also mutually exclusive with the other ones.

Building as a module on master-art

1. Check out the master-art tree:

   repo init -b master-art -u <repository url>
   

   See the Android source access instructions for further details. Google internal users please see go/sync.

2. Set up the development environment:

   See art/test/README.chroot.md for details on how to set up the environment on master-art, but the lunch step can be skipped. Instead use banchan to initialize an unbundled module build:

   source build/envsetup.sh
   banchan com.android.art <arch>
   

   <arch> is the device architecture - use hmm to see the options. Regardless of the device architecture, the build also includes the usual host architectures, and 64/32-bit multilib for the 64-bit products.

   To build the debug variant of the module, specify com.android.art.debug instead of com.android.art. It is also possible to list both.

3. Build the module:

   m apps_only dist
   

4. Install the module and reboot:

   adb install out/dist/com.android.art.apex
   adb reboot
   

   The name of the APEX file depends on what you passed to banchan.

Building as part of the base system image

NOTE: This method of building is slated to be obsoleted in favor of the module build on master-art above (b/172480617).

1. Check out a full Android platform tree and lunch the appropriate product the normal way.

2. Ensure the ART Module is built from source:

   Active development on ART module happens in trunk_staging release configuration. Whenever possible, use this configuration for local development.

   lunch <product>-trunk_staging-<variant>
   

   Some release configurations use prebuilts of ART module. To verify whether a particular release configuration uses ART prebuilts, run the following command

   get_build_var RELEASE_APEX_CONTRIBUTIONS_ART
   

   If this returns a non-empty value, it usually means that this release configuration uses ART prebuilts. (To verify, you can inspect the contents of the apex_contributions Android.bp module reported by the above command.)

   For troubleshooting, it might be desirable to build ART from source in that release configuration. To do so, please modify the .scl file and unset the RELEASE_APEX_CONTIRBUTIONS_ART build flag. To determine which .scl files are used in the current release configuration, please refer to out/release_config_entrypoint.scl.

3. Build the system image the normal way, for example:

   m droid
   

Prebuilts

Prebuilts are used for the ART Module dependencies that have sources outside the master-art manifest. Conversely the ART Module may be a prebuilt when used in platform builds of the base system image.

The locations of the prebuilts are:

• prebuilts/runtime/mainline for prebuilts and SDKs required to build the ART Module.

  See prebuilts/runtime/mainline/README.md for instructions on how to update them.

• packages/modules/ArtPrebuilt for the ART Module APEX packages, if present.

• prebuilts/module_sdk/art for the ART Module SDK and other tools, needed to build platform images and other modules that depend on the ART Module.