Revision 942899 of Simple Firefox build

<p>This page covers the basic steps needed to build a bleeding-edge, development version of Firefox. For additional, more detailed information, see the <a class="internal" href="/en-US/docs/Mozilla/Developer_guide/Build_Instructions" title="/en-US/docs/Developer_Guide/Build_Instructions">build documentation</a>.</p>

<h2 id="Build_prerequisites">Build prerequisites</h2>

<h3 id="Hardware_Requirements">Hardware Requirements:</h3>

<ul>
 <li>While you can build Firefox on older hardware it can take quite a bit of time to compile on slower machines, and having at least 8GB of RAM is recommended.</li>
 <li>Fast broadband internet is strongly recommended as well. Both the development environment and the source code repository are quite large.</li>
 <li>You must have a 64-bit operating system. As of early 2015 it is no longer possible to build Firefox on most 32-bit machines.</li>
</ul>

<h3 id="Setup">Setup:</h3>

<p>Depending on your Operating System you will need to carry out a different process to prepare your machine. So firstly complete the instructions for your OS and then continue following these build instructions.</p>

<ul>
 <li><a href="/en-US/docs/Developer_Guide/Build_Instructions/Windows_Prerequisites" title="/en-US/docs/Developer_Guide/Build_Instructions/Windows_Prerequisites">Windows Build Prerequisites</a></li>
 <li><a href="/en-US/docs/Simple_Firefox_build/Linux_and_MacOS_build_preparation" title="/en-US/docs/Simple_Firefox_build/Linux_and_MacOS_build_preparation">Linux Build Prerequisites</a></li>
 <li><a href="/en-US/docs/Mozilla/Developer_guide/Build_Instructions/Mac_OS_X_Prerequisites">Mac OS X Build Prerequisites</a></li>
</ul>

<p><strong>TIP</strong>: After completing Setup for your OS, and before you Get the source, you can opt to add the progressExtension to your mercurial.ini (for Windows) or .hgrc (for *Nix / Mac) file. This will provide status feedback during the lengthy clone / download process. see: <a href="https://mercurial.selenic.com/wiki/ProgressExtension">Configure Mercurial .hgrc file for Progress Extension</a>.</p>

<h2 id="Get_the_source">Get the source</h2>

<p>Get the latest source code from Mozilla's Mercurial code repository. This may take a while; it's a lot of code!</p>

<pre>
hg clone https://hg.mozilla.org/mozilla-central
</pre>

<p>If you are using a slow or unreliable internet connection, "hg clone" might fail because it gets interrupted. In that case, you are strongly encouraged to download a <a href="/en-US/docs/Mozilla/Developer_guide/Source_Code/Mercurial/Bundles" title="/en-US/docs/Developer_Guide/Source_Code/Mercurial/Bundles">Mercurial bundle</a> file instead of waiting for "hg clone".</p>

<h2 id="Build_configuration_(optional)">Build configuration (optional)</h2>

<p>By default, the build system creates a release build of Firefox roughly equivalent to the official Firefox release builds. If that's not exactly what you want, there are many build configuration options to choose from, although it's <strong>strongly</strong> recommended that you only use options that you fully understand.</p>

<p>The normal way to specify build options is to place them in a file named <code>mozconfig</code> at the root of your mozilla source tree (that is, directly under the <code>mozilla-central</code> directory created by the <code>hg clone</code> command). On Windows, you can create the file from the MozillaBuild command-line:</p>

<pre class="eval">
cd /path/to/mozilla-central
touch .mozconfig
</pre>

<p>For example, if you're planning on hacking the C/C++ code, you probably want to create a debug build instead of a release build, by adding the following lines to <code>mozconfig</code>:</p>

<pre>
ac_add_options --enable-debug
ac_add_options --disable-optimize
</pre>

<p>For more on configuration options, see the page on <a href="/en-US/docs/Configuring_Build_Options" title="/en-US/docs/Configuring_Build_Options">configuring build options</a>.</p>

<h2 id="Building">Building</h2>

<p>To configure mercurial for <code>mach</code>, run:</p>

<pre>
./mach mercurial-setup
</pre>

<p><br />
 To start the build, cd into the <code>mozilla-central </code>subdirectory (created automatically by the <code>hg clone</code> command), and run:</p>

<pre>
./mach build
</pre>

<p>mach is our command-line tool to streamline common developer tasks. See the <a href="/en-US/docs/Developer_Guide/mach" title="/en-US/docs/Developer_Guide/mach">mach</a> article for more.</p>

<p>The first time you run "./mach build", mach will ask you if you'd like to create a ".mozbuild" directory in your home folder and wait 20 seconds for your answer. This a good default setting, and you should allow it to finish.</p>

<p>Building can take a significant amount of time, depending on your system, OS and chosen build options. Linux builds on a fast box may take under 15 minutes, but Windows builds on a slow box may take several hours. See <strong><a href="/en-US/docs/Developer_Guide/Mozilla_build_FAQ#Making_builds_faster" title="/en-US/docs/Developer_Guide/Mozilla_build_FAQ#Making_builds_faster">tips for making builds faster</a></strong>.</p>

<h2 id="Running">Running</h2>

<p>Various temporary files, libraries, and the Firefox executable will be found in your <strong>object directory</strong> (under <code>mozilla-central/</code>), which is prefixed with <strong><code>obj-</code></strong>. The exact name depends on your system and OS. For example, a Mac user may get an object directory name of <strong><code>obj-x86_64-apple-darwin10.7.3/</code></strong>.</p>

<p>To run the newly created Firefox instance, use the mach command</p>

<pre>
./mach run</pre>

<p>The Firefox executable and its dependencies are located under the <code>dist/bin</code> folder under the object directory. In particular, Firefox is (depending on the OS) at</p>

<ul>
 <li><strong>Windows:</strong> <code>obj-.../dist/bin/firefox.exe</code></li>
 <li><strong>Linux:</strong> <code>obj-.../dist/bin/firefox</code></li>
 <li><strong>OS X:</strong> <code>obj-.../dist/Nightly.app/Contents/MacOS/firefox</code></li>
</ul>

<h2 id="Rebuilding">Rebuilding</h2>

<p>To build after making changes, run</p>

<pre>
./mach build
</pre>

<p>again. This will only rebuild what is necessary for these changes. It is also possible to use</p>

<pre>
./mach build <var>path/to/dir</var>
</pre>

<p>to build parts of the tree. However, this approach may or may not yield correct results, so it is <strong>not recommended</strong>.</p>

<h2 id="How_to_update">How to update</h2>

<p>To pull the latest changes and update the code in your <code>mozilla-central</code> working directory, run the command:</p>

<pre>
hg pull -u
</pre>

<p>and run <code>./mach build</code>. Due to the high rate of changes to Firefox, this may take quite a long time.</p>