Configuring Build Options ========================= +--------------------------------------------------------------------+ | This page is an import from MDN and the contents might be outdated | +--------------------------------------------------------------------+ This document details how to configure Firefox builds. Most of the time a ``mozconfig`` file is not required. The default options are the most well-supported, so it is preferable to add as few options as possible. Please read the following directions carefully before building, and follow them in order. Skipping any step may cause the build to fail, or the built software to be unusable. Build options, including options not usable from the command-line, may appear in "``confvars.sh``" files in the source tree. Using a ``mozconfig`` configuration file ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The choice of which Mozilla project to build and other configuration options can be configured in a ``mozconfig`` file. (It is possible to manually call ``configure`` with command-line options, but this is not recommended). The ``mozconfig`` file should be in your source directory (that is, ``/mozilla-central/mozconfig``). Create a blank ``mozconfig`` file: .. code:: bash echo "# My first mozilla config" > mozconfig If your mozconfig isn't in your source directory, you can also use the ``MOZCONFIG`` environment variable to specify the path to your ``mozconfig``. The path you specify **must** be an **absolute** path or else ``client.mk`` will not find it. This is useful if you choose to have multiple ``mozconfig`` files for different projects or configurations (see below for a full example). Note that in the ``export`` example below the filename was not ``mozconfig``. Regardless of the name of the actual file you use, we refer to this file as the ``mozconfig`` file in the examples below. Setting the ``mozconfig`` path: .. code:: bash export MOZCONFIG=$HOME/mozilla/mozconfig-firefox .. note:: Calling the file ``.mozconfig`` (with a leading dot) is also supported, but this is not recommended because it may make the file harder to find. This will also help when troubleshooting because people will want to know which build options you have selected and will assume that you have put them in your ``mozconfig`` file. ``mozconfig`` contains two types of options: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - Options prefixed with ``mk_add_options`` are passed to ``client.mk``. The most important of these is ``MOZ_OBJDIR``, which controls where your project gets built (also known as the object directory). - Options prefixed with ``ac_add_options`` are passed to ``configure``, and affect the build process. Building with an objdir ~~~~~~~~~~~~~~~~~~~~~~~ This means that the source code and object files are not intermingled in your directory system and you can build multiple projects (e.g., Firefox and Thunderbird) from the same source tree. If you do not specify a ``MOZ_OBJDIR``, it will be automatically set to ``@TOPSRCDIR@/obj-@CONFIG_GUESS@``. If you need to re-run ``configure``, the easiest way to do it is using ``./mach configure``; running ``configure`` manually is strongly discouraged. Adding the following line to your ``mozconfig`` allows you to change the objdir: .. code:: bash mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/obj-@CONFIG_GUESS@ It is a good idea to have your objdir name start with ``obj`` so that Mercurial ignores it. Sometimes it can be useful to build multiple versions of the source (such as with and without diagnostic asserts). To avoid the time it takes to do a full rebuild, you can create multiple ``mozconfig`` files which specify different objdirs. For example, a ``mozconfig-dbg``: .. code:: bash mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/obj-ff-dbg ac_add_options --enable-debug and a ``mozconfig-rel-opt``: .. code:: bash mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/obj-ff-rel-opt ac_add_options --disable-debug ac_add_options --enable-optimize allow for building both versions by specifying the configuration via the ``MOZCONFIG`` environment variable: .. code:: bash $ env MOZCONFIG=/path/to/mozconfig-dbg ./mach build $ env MOZCONFIG=/path/to/mozconfig-rel-opt ./mach build Don't forget to set the ``MOZCONFIG`` environment variable for the ``mach run`` command as well. Be aware that changing your ``mozconfig`` will require the configure process to be rerun and therefore the build will take considerably longer, so if you find yourself changing the same options regularly, it may be worth having a separate ``mozconfig`` for each. The main downside of this is that each objdir will take up a significant amount of space on disk. Parallel compilation ~~~~~~~~~~~~~~~~~~~~ .. note:: The build system automatically makes an intelligent guess for how many CPU cores to use when building. The option below is typically not needed. Most modern systems have multiple cores or CPUs, and they can be optionally used concurrently to make the build faster. The ``-j`` flag controls how many parallel builds will run concurrently. You will see (diminishing) returns up to a value approximately 1.5× to 2.0× the number of cores on your system. .. code:: bash mk_add_options MOZ_PARALLEL_BUILD=4 If your machine is overheating, you might want to try a lower value. Choose a project ~~~~~~~~~~~~~~~~ The ``--enable-project=project`` flag is used to select a project to build. Firefox is the default. Choose one of the following options to add to your ``mozconfig`` file: Browser (Firefox) .. code:: ac_add_options --enable-project=browser .. note:: This is the default Mail (Thunderbird) .. code:: ac_add_options --enable-project=comm/mail Mozilla Suite (SeaMonkey) .. code:: ac_add_options --enable-project=suite Calendar (Lightning Extension, uses Thunderbird) .. code:: ac_add_options --enable-project=comm/mail ac_add_options --enable-calendar Selecting build options ~~~~~~~~~~~~~~~~~~~~~~~ The build options you choose depends on what project you are building and what you will be using the build for. If you want to use the build regularly, you will want a release build without extra debugging information; if you are a developer who wants to hack the source code, you probably want a non-optimized build with extra debugging macros. There are many options recognized by the configure script which are special-purpose options intended for embedders or other special situations, and should not be used to build the full suite/XUL projects. The full list of options can be obtained by running ``./mach configure -- --help``. .. warning:: Do not use a configure option unless you know what it does. The default values are usually the right ones. Each additional option you add to your ``mozconfig`` file reduces the chance that your build will compile and run correctly. The following build options are very common: sccache ^^^^^^^ `SCCache `__ allows speeding up subsequent C / C++ builds by caching compilation results. Unlike `ccache `__, it also allows caching Rust artifacts, and supports `distributed compilation `__. In order to enable ``sccache`` for Firefox builds, you can use ``ac_add_options --with-ccache=sccache``. From version 0.7.4, sccache local builds are using the ``preprocessor cache mode`` by default. With a hot cache, it decreases the build time by a factor of 2 to 3 compared the previous method. This feature works like the `direct mode in ccache `__, using a similar way to handle caching and dependencies. .. note:: When using sccache, because of the operation on the files and storage, the initial build of Firefox will be slower. Optimization ^^^^^^^^^^^^ ``ac_add_options --enable-optimize`` Enables the default compiler optimization options .. note:: This is enabled by default ``ac_add_options --enable-optimize=-O2`` Chooses particular compiler optimization options. In most cases, this will not give the desired results, unless you know the Mozilla codebase very well; note, however, that if you are building with the Microsoft compilers, you probably **do** want this as ``-O1`` will optimize for size, unlike GCC. ``ac_add_options --enable-debug`` Enables assertions in C++ and JavaScript, plus other debug-only code. This can significantly slow a build, but it is invaluable when writing patches. **People developing patches (especially in C++) should generally use this option.** ``ac_add_options --disable-optimize`` Disables compiler optimization. This makes it much easier to step through code in a debugger. ``ac_add_options --enable-release`` Enables more conservative, release engineering-oriented options. This may slow down builds. This also turns on full optimizations for Rust. Note this is the default when building release/beta/esr. ``ac_add_options --enable-debug-js-modules`` Enable only JavaScript assertions. This is useful when working locally on JavaScript-powered components like the DevTools. This will help catch any errors introduced into the JS code, with less of a performance impact compared to the ``--enable-debug`` option. ``export RUSTC_OPT_LEVEL=2`` Enable full optimizations for Rust code. You can make an optimized build with debugging symbols. See :ref:`Building with Debug Symbols `. Extensions ^^^^^^^^^^ ``ac_add_options --enable-extensions=default|all|ext1,ext2,-skipext3`` There are many optional pieces of code that live in {{ Source("extensions/") }}. Many of these extensions are now considered an integral part of the browsing experience. There is a default list of extensions for the suite, and each app-specific ``mozconfig`` specifies a different default set. Some extensions are not compatible with all apps, for example: - ``cookie`` is not compatible with thunderbird - ``typeaheadfind`` is not compatible with any toolkit app (Firefox, Thunderbird) Unless you know which extensions are compatible with which apps, do not use the ``--enable-extensions`` option; the build system will automatically select the proper default set of extensions. Tests ^^^^^ ``ac_add_options --disable-tests`` By default, many auxiliary test programs are built, which can help debug and patch the mozilla source. Disabling these tests can speed build time and reduce disk space considerably. Developers should generally not use this option. Localization ^^^^^^^^^^^^ ``mk_add_options MOZ_CO_LOCALES=ISOcode`` TBD. ``ac_add_options --enable-ui-locale=ISOcode`` TBD. ``ac_add_options --with-l10n-base=/path/to/base/dir`` TBD. Other Options ^^^^^^^^^^^^^ ``mk_add_options AUTOCLOBBER=1`` If a clobber would be required before a build, this will cause mach to clobber and continue with the build instead of asking the user to manually clobber and exiting. ``ac_add_options --enable-warnings-as-errors`` This makes compiler warnings into errors which fail the build. This can be useful since certain warnings coincide with reviewbot lints which must be fixed before merging. .. _Example_.mozconfig_Files: Example ``mozconfig`` Files ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Mozilla's official builds use mozconfig files from the appropriate directory within each repository. .. warning:: These ``mozconfig`` files are taken from production builds and are provided as examples only. It is recommended to use the default build options, and only change the properties from the list above as needed. The production builds aren't really appropriate for local builds." - .. rubric:: Firefox, `Debugging Build (macOS 64bits) `__ :name: Firefox.2C_Default_Release_Configuration Building multiple projects from the same source tree ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ It is possible to build multiple projects from the same source tree, as long as you `use a different objdir <#Building_with_an_Objdir>`__ for each project. You need to create multiple ``mozconfig`` files. As an example, the following steps can be used to build Firefox and Thunderbird. You should first create three ``mozconfig`` files. ``mozconfig-common``: .. code:: # add common options here, such as making an optimized release build mk_add_options MOZ_PARALLEL_BUILD=4 ac_add_options --enable-optimize --disable-debug ``mozconfig-firefox``: .. code:: # include the common mozconfig . ./mozconfig-common # Build Firefox mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/obj-firefox ac_add_options --enable-project=browser ``mozconfig-thunderbird``: .. code:: # include the common mozconfig . ./mozconfig-common # Build Thunderbird mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/obj-thunderbird ac_add_options --enable-project=comm/mail To build Firefox, run the following commands: .. code:: export MOZCONFIG=/path/to/mozilla/mozconfig-firefox ./mach build To build Thunderbird, run the following commands: .. code:: export MOZCONFIG=/path/to/mozilla/mozconfig-thunderbird ./mach build Using mozconfigwrapper ^^^^^^^^^^^^^^^^^^^^^^ Mozconfigwrapper is similar to using multiple mozconfig files except that it abstracts and hides them so you don't have to worry about where they live or which ones you've created. It also saves you from having to export the MOZCONFIG variable each time. For information on installing and configuring mozconfigwrapper, see https://github.com/ahal/mozconfigwrapper.