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