docs/meson.html

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   5   <title>Compilation and Installation using Meson</title>
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  10 <div class="header">
  11   <h1>The Mesa 3D Graphics Library</h1>
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  16
  17 <h1>Compilation and Installation using Meson</h1>
  18
  19 <h2 id="basic">1. Basic Usage</h2>
  20
  21 <p><strong>The Meson build system is generally considered stable and ready
  22 for production</strong></p>
  23
  24 <p>The meson build is tested on on Linux, macOS, Cygwin and Haiku, it should
  25 work on FreeBSD, DragonflyBSD, NetBSD, and OpenBSD.</p>
  26
  27 <p><strong>Mesa requires Meson >= 0.44.1 to build.</strong>
  28
  29 Some older versions of meson do not check that they are too old and will error
  30 out in odd ways.
  31 </p>
  32
  33 <p>
  34 The meson program is used to configure the source directory and generates
  35 either a ninja build file or Visual Studio® build files. The latter must
  36 be enabled via the --backend switch, as ninja is the default backend on all
  37 operating systems. Meson only supports out-of-tree builds, and must be passed a
  38 directory to put built and generated sources into. We'll call that directory
  39 "build" for examples.
  40 </p>
  41
  42 <pre>
  43     meson build/
  44 </pre>
  45
  46 <p>
  47 To see a description of your options you can run <code>meson configure</code>
  48 along with a build directory to view the selected options for. This will show
  49 your meson global arguments and project arguments, along with their defaults
  50 and your local settings.
  51
  52 Meson does not currently support listing options before configure a build
  53 directory, but this feature is being discussed upstream.
  54 </p>
  55
  56 <pre>
  57     meson configure build/
  58 </pre>
  59
  60 <p>
  61 With additional arguments <code>meson configure</code> is used to change
  62 options on already configured build directory. All options passed to this
  63 command are in the form -D "command"="value".
  64 </p>
  65
  66 <pre>
  67     meson configure build/ -Dprefix=/tmp/install -Dglx=true
  68 </pre>
  69
  70 <p>
  71 Once you've run the initial <code>meson</code> command successfully you can use
  72 your configured backend to build the project. With ninja, the -C option can be
  73 be used to point at a directory to build.
  74 </p>
  75
  76 <pre>
  77     ninja -C build/
  78 </pre>
  79
  80 <p>
  81 Without arguments, it will produce libGL.so and/or several other libraries
  82 depending on the options you have chosen. Later, if you want to rebuild for a
  83 different configuration, you should run <code>ninja clean</code> before
  84 changing the configuration, or create a new out of tree build directory for
  85 each configuration you want to build.
  86
  87 http://mesonbuild.com/Using-multiple-build-directories.html
  88 </p>
  89
  90 <dt><code>Environment Variables</code></dt>
  91 <dd><p>Meson supports the standard CC and CXX environment variables for
  92 changing the default compiler, and CFLAGS, CXXFLAGS, and LDFLAGS for setting
  93 options to the compiler and linker.
  94
  95 The default compilers depends on your operating system. Meson supports most of
  96 the popular compilers, a complete list is available
  97 <a href="http://mesonbuild.com/Reference-tables.html#compiler-ids">here</a>.
  98
  99 These arguments are consumed and stored by meson when it is initialized or
 100 re-initialized. Therefore passing them to meson configure will not do anything,
 101 and passing them to ninja will only do something if ninja decides to
 102 re-initialize meson, for example, if a meson.build file has been changed.
 103 Changing these variables will not cause all targets to be rebuilt, so running
 104 ninja clean is recommended when changing CFLAGS or CXXFLAGS. Meson will never
 105 change compiler in a configured build directory.
 106 </p>
 107
 108 <pre>
 109     CC=clang CXX=clang++ meson build-clang
 110     ninja -C build-clang
 111     ninja -C build-clang clean
 112     touch meson.build
 113     CFLAGS=-Wno-typedef-redefinition ninja -C build-clang
 114 </pre>
 115
 116 <p>Meson also honors DESTDIR for installs</p>
 117 </dd>
 118
 119
 120 <dl>
 121 <dt><code>LLVM</code></dt>
 122 <dd><p>Meson includes upstream logic to wrap llvm-config using it's standard
 123 dependency interface. It will search $PATH (or %PATH% on windows) for
 124 llvm-config, so using an LLVM from a non-standard path is as easy as
 125 <code>PATH=/path/with/llvm-config:$PATH meson build</code>.
 126 </p></dd>
 127 </dl>
 128
 129 <dl>
 130 <dt><code>PKG_CONFIG_PATH</code></dt>
 131 <dd><p>The
 132 <code>pkg-config</code> utility is a hard requirement for configuring and
 133 building Mesa on Unix-like systems. It is used to search for external libraries
 134 on the system. This environment variable is used to control the search path for
 135 <code>pkg-config</code>. For instance, setting
 136 <code>PKG_CONFIG_PATH=/usr/X11R6/lib/pkgconfig</code> will search for package
 137 metadata in <code>/usr/X11R6</code> before the standard directories.</p>
 138 </dd>
 139 </dl>
 140
 141 <p>
 142 One of the oddities of meson is that some options are different when passed to
 143 the <code>meson</code> than to <code>meson configure</code>. These options are
 144 passed as --option=foo to <code>meson</code>, but -Doption=foo to <code>meson
 145 configure</code>. Mesa defined options are always passed as -Doption=foo.
 146 <p>
 147
 148 <p>For those coming from autotools be aware of the following:</p>
 149
 150 <dl>
 151 <dt><code>--buildtype/-Dbuildtype</code></dt>
 152 <dd><p>This option will set the compiler debug/optimisation levels to aid
 153 debugging the Mesa libraries.</p>
 154
 155 <p>Note that in meson this defaults to "debugoptimized", and  not setting it to
 156 "release" will yield non-optimal performance and binary size. Not using "debug"
 157 may interfere with debugging as some code and validation will be optimized
 158 away.
 159 </p>
 160
 161 <p> For those wishing to pass their own optimization flags, use the "plain"
 162 buildtype, which causes meson to inject no additional compiler arguments, only
 163 those in the C/CXXFLAGS and those that mesa itself defines.</p>
 164 </dd>
 165 </dl>
 166
 167 <dl>
 168 <dt><code>-Db_ndebug</code></dt>
 169 <dd><p>This option controls assertions in meson projects. When set to false
 170 (the default) assertions are enabled, when set to true they are disabled. This
 171 is unrelated to the <code>buildtype</code>; setting the latter to
 172 <code>release</code> will not turn off assertions.
 173 </p>
 174 </dd>
 175 </dl>