Android --- Setting up a Linux build environment

Setting up a Linux build environment

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These instructions apply to all branches, including master.

The Android build is routinely tested in house on recent versions ofUbuntu LTS (14.04), but most distributions should have the requiredbuild tools available. Reports of successes or failures on otherdistributions are welcome.

For Gingerbread (2.3.x) and newer versions, including the masterbranch, a 64-bit environment is required. Older versions can becompiled on 32-bit systems.

Note: See the Requirements for the complete list of hardware andsoftware requirements. Then follow the detailed instructions for Ubuntu and MacOS below.

Installing the JDK

The master branch of Android in the Android Open Source Project (AOSP)requires Java 8. On Ubuntu, use OpenJDK.

See JDK Requirements for olderversions.

For Ubuntu >= 15.04

Run the following:

$ sudo apt-get update
$ sudo apt-get install openjdk-8-jdk

For Ubuntu LTS 14.04

There are no available supported OpenJDK 8 packages for Ubuntu 14.04. TheUbuntu 15.04 OpenJDK 8 packages have been used successfullywith Ubuntu 14.04. Newer package versions (e.g. those for 15.10, 16.04) werefound not to work on 14.04 using the instructions below.

1. Download the .deb packages for 64-bit architecture fromarchive.ubuntu.com:

   • openjdk-8-jre-headless_8u45-b14-1_amd64.debwith SHA256 0f5aba8db39088283b51e00054813063173a4d8809f70033976f83e214ab56c0
   • openjdk-8-jre_8u45-b14-1_amd64.debwith SHA256 9ef76c4562d39432b69baf6c18f199707c5c56a5b4566847df908b7d74e15849
   • openjdk-8-jdk_8u45-b14-1_amd64.debwith SHA256 6e47215cf6205aa829e6a0a64985075bd29d1f428a4006a80c9db371c2fc3c4c

2. Optionally, confirm the checksums of the downloaded files against the SHA256string listed with each package above.

   For example, with the sha256sum tool:

   $ sha256sum {downloaded.deb file}

3. Install the packages:

   $ sudo apt-get update

   Run dpkg for each of the .deb files you downloaded. It may produce errors due tomissing dependencies:

   $ sudo dpkg -i {downloaded.deb file}

   To fix missing dependencies:

   $ sudo apt-get -f install

Update the default Java version - optional

Optionally, for the Ubuntu versions above update the default Java version byrunning:

$ sudo update-alternatives --config java
$ sudo update-alternatives --config javac

If, during a build, you encounter version errors for Java, set itspath as described in the WrongJava Version section.

Installing required packages (Ubuntu 14.04)

You will need a 64-bit version of Ubuntu. Ubuntu 14.04 is recommended.

$ sudo apt-get install git-core gnupg flex bison gperf build-essential \
  zip curl zlib1g-dev gcc-multilib g++-multilib libc6-dev-i386 \
  lib32ncurses5-dev x11proto-core-dev libx11-dev lib32z-dev ccache \
  libgl1-mesa-dev libxml2-utils xsltproc unzip

Note: To use SELinux tools for policyanalysis, also install the python-networkx package.

Note: If you are using LDAP and wantto run ART host tests, also install the libnss-sss:i386package.

Installing required packages (Ubuntu 12.04)

You may use Ubuntu 12.04 to build older versions of Android. Version 12.04 is not supported on master or recent releases.

$ sudo apt-get install git gnupg flex bison gperf build-essential \
  zip curl libc6-dev libncurses5-dev:i386 x11proto-core-dev \
  libx11-dev:i386 libreadline6-dev:i386 libgl1-mesa-glx:i386 \
  libgl1-mesa-dev g++-multilib mingw32 tofrodos \
  python-markdown libxml2-utils xsltproc zlib1g-dev:i386
$ sudo ln -s /usr/lib/i386-linux-gnu/mesa/libGL.so.1 /usr/lib/i386-linux-gnu/libGL.so

Installing required packages (Ubuntu 10.04 -- 11.10)

Building on Ubuntu 10.04-11.10 is no longer supported, but may be useful for building olderreleases of AOSP.

$ sudo apt-get install git gnupg flex bison gperf build-essential \
  zip curl zlib1g-dev libc6-dev lib32ncurses5-dev ia32-libs \
  x11proto-core-dev libx11-dev lib32readline5-dev lib32z-dev \
  libgl1-mesa-dev g++-multilib mingw32 tofrodos python-markdown \
  libxml2-utils xsltproc

On Ubuntu 10.10:

$ sudo ln -s /usr/lib32/mesa/libGL.so.1 /usr/lib32/mesa/libGL.so

On Ubuntu 11.10:

$ sudo apt-get install libx11-dev:i386

Configuring USB Access

Under GNU/Linux systems (and specifically under Ubuntu systems),regular users can't directly access USB devices by default. Thesystem needs to be configured to allow such access.

The recommended approach is to create a file at/etc/udev/rules.d/51-android.rules (as the root user).

To do this, run the following command to download the 51-android.rules file attached to this site, modify it to include your username, and place it in the correct location:

$ wget -S -O - http://source.android.com/source/51-android.rules | sed "s/<username>/$USER/" | sudo tee >/dev/null /etc/udev/rules.d/51-android.rules; sudo udevadm control --reload-rules

Those new rules take effect the next time a device is plugged in.It might therefore be necessary to unplug the device and plug itback into the computer.

Using a separate output directory

By default, the output of each build is stored in the out/subdirectory of the matching source tree.

On some machines with multiple storage devices, builds arefaster when storing the source files and the output onseparate volumes. For additional performance, the outputcan be stored on a filesystem optimized for speed insteadof crash robustness, since all files can be re-generatedin case of filesystem corruption.

To set this up, export the OUT_DIR_COMMON_BASE variableto point to the location where your output directorieswill be stored.

export OUT_DIR_COMMON_BASE=<path-to-your-out-directory>

The output directory for each separate source tree will benamed after the directory holding the source tree.

For instance, if you have source trees as /source/master1and /source/master2 and OUT_DIR_COMMON_BASE is set to/output, the output directories will be /output/master1and /output/master2.

It's important in that case to not have multiple sourcetrees stored in directories that have the same name,as those would end up sharing an output directory, withunpredictable results.

This is only supported on Jelly Bean (4.1) and newer,including the master branch.

Setting up a Mac OS build environment

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In a default installation, Mac OS runs on a case-preserving but case-insensitivefilesystem. This type of filesystem is not supported by git and will cause somegit commands (such as git status) to behave abnormally. Because of this, werecommend that you always work with the AOSP source files on a case-sensitivefilesystem. This can be done fairly easily using a disk image, discussed below.

Once the proper filesystem is available, building the master branch in a modernMac OS environment is very straightforward. Earlier branches, including ICS,require some additional tools and SDKs.

Creating a case-sensitive disk image

You can create a case-sensitive filesystem within your existing Mac OS environmentusing a disk image. To create the image, launch DiskUtility and select "New Image". A size of 25GB is the minimum tocomplete the build; larger numbers are more future-proof. Using sparse imagessaves space while allowing to grow later as the need arises. Be sure to select"case sensitive, journaled" as the volume format.

You can also create it from a shell with the following command:

# hdiutil create -type SPARSE -fs 'Case-sensitive Journaled HFS+' -size 40g ~/android.dmg

This will create a .dmg (or possibly a .dmg.sparseimage) file which, once mounted, acts as a drive with the required formatting for Android development.

If you need a larger volume later, you can also resize the sparse image with the following command:

# hdiutil resize -size <new-size-you-want>g ~/android.dmg.sparseimage

For a disk image named android.dmg stored in your home directory, you can add helper functions to your ~/.bash_profile:

• To mount the image when you execute mountAndroid:

  # mount the android file image
  function mountAndroid { hdiutil attach ~/android.dmg -mountpoint /Volumes/android; }
  

  Note: If your system created a .dmg.sparseimage file, replace ~/android.dmg with ~/android.dmg.sparseimage.

• To unmount it when you execute umountAndroid:

  # unmount the android file image
  function umountAndroid() { hdiutil detach /Volumes/android; }
  

Once you've mounted the android volume, you'll do all your work there. You can eject it (unmount it) just like you would with an external drive.

Installing the JDK

See Requirements for the version of Java to use when developing various versions of Android.

Installing required packages

• Install Xcode from the Apple developer site.If you are not already registered as an Apple developer, you will have tocreate an Apple ID in order to download.

• Install MacPorts from macports.org.

  Note: Make sure that /opt/local/bin appears in your path before /usr/bin. If not, please add the following to your ~/.bash_profile file:

  export PATH=/opt/local/bin:$PATH

  Note: If you do not have a.bash_profile file in your home directory, create one.

• Get make, git, and GPG packages from MacPorts:

  $ POSIXLY_CORRECT=1 sudo port install gmake libsdl git gnupg
  

  If using Mac OS X v10.4, also install bison:

  $ POSIXLY_CORRECT=1 sudo port install bison
  

Reverting from make 3.82

In Android 4.0.x (Ice Cream Sandwich) and earlier, a bug exists in gmake 3.82that prevents android from building. You can install version 3.81 usingMacPorts with these steps:

• Edit /opt/local/etc/macports/sources.conf and add a line that says

  file:///Users/Shared/dports
  

  above the rsync line. Then create this directory:

  $ mkdir /Users/Shared/dports
  

• In the new dports directory, run

  $ svn co --revision 50980 http://svn.macports.org/repository/macports/trunk/dports/devel/gmake/ devel/gmake/
  

• Create a port index for your new local repository:

  $ portindex /Users/Shared/dports
  

• Finally, install the old version of gmake with

  $ sudo port install gmake @3.81
  

Setting a file descriptor limit

On Mac OS, the default limit on the number of simultaneous file descriptorsopen is too low and a highly parallel build process may exceed this limit.

To increase the cap, add the following lines to your ~/.bash_profile:

# set the number of open files to be 1024
ulimit -S -n 1024

Optimizing a build environment (optional)

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Setting up ccache

You can optionally tell the build to use the ccache compilation tool, whichis a compiler cache for C and C++ that can help make builds faster. Itis especially useful for build servers and other high-volume productionenvironments. Ccache acts as a compiler cache that can be used to speed up rebuilds.This works very well if you use make clean often, or if you frequentlyswitch between different build products.

Note: If you're instead conducting incrementalbuilds (such as an individual developer rather than a build server), ccache mayslow your builds down by making you pay for cache misses.

To use ccache, issue these commands in the root of the source tree:

$ export USE_CCACHE=1
$ export CCACHE_DIR=/<path_of_your_choice>/.ccache
$ prebuilts/misc/linux-x86/ccache/ccache -M 50G

The suggested cache size is 50-100G.

Put the following in your .bashrc (or equivalent):

export USE_CCACHE=1

By default the cache will be stored in ~/.ccache.If your home directory is on NFS or some other non-local filesystem,you will want to specify the directory in your .bashrc file too.

On Mac OS, you should replace linux-x86 with darwin-x86:

$ prebuilts/misc/darwin-x86/ccache/ccache -M 50G

When building Ice Cream Sandwich (4.0.x) or older, ccache is ina different location:

prebuilt/linux-x86/ccache/ccache -M 50G

This setting is stored in the CCACHE_DIR and is persistent.

On Linux, you can watch ccache being used by doing the following:

$ watch -n1 -d prebuilts/misc/linux-x86/ccache/ccache -s