[Mesa-dev] [PATCH] docs: add documentation for building with meson

Wed Nov 8 18:59:49 UTC 2017

Is there a way to get a list of options before having any success?  I
want to disable using LLVM, but I can't get the list of options to do so
because I don't have libelf (required for LLVM... which I don't want):

Dependency libelf found: NO

Meson encountered an error in file meson.build, line 628, column 2:
C library 'elf' not found

On 11/07/2017 09:28 AM, Dylan Baker wrote:
> v2: - Add information about CC, CXX, CFLAGS, and CXXFLAGS (Nicolai)
>     - Add message at top that meson for mesa is still a work in progress
>     - Add trailing "/" to directories (Eric E.)
>     - Fix a number of spelling/grammar/style suggestions from Eric E.
>     - Make a number of changes as suggested by Emil.
> v3: - Fix order of commands in example (Eric E.)
>     - Add documentation for overriding LLVM version (Eric E.)
> v4: - Rebase on master
>     - update default buildtype
>     - add note about b_ndebug
>     - Clarify meson configure a bit
> 
> Signed-off-by: Dylan Baker <dylanx.c.baker at intel.com>
> Reviewed-by: Eric Engestrom <eric at engestrom.ch> (v3)
> ---
>  docs/contents.html |   1 +
>  docs/meson.html    | 151 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 152 insertions(+)
>  create mode 100644 docs/meson.html
> 
> diff --git a/docs/contents.html b/docs/contents.html
> index d5455421091..9a86019e2f6 100644
> --- a/docs/contents.html
> +++ b/docs/contents.html
> @@ -43,6 +43,7 @@
>  <li><a href="install.html" target="_parent">Compiling / Installing</a>
>    <ul>
>      <li><a href="autoconf.html" target="_parent">Autoconf</a></li>
> +    <li><a href="meson.html" target="_parent">Meson</a></li>
>    </ul>
>  </li>
>  <li><a href="precompiled.html" target="_parent">Precompiled Libraries</a>
> diff --git a/docs/meson.html b/docs/meson.html
> new file mode 100644
> index 00000000000..ee505b1d5ee
> --- /dev/null
> +++ b/docs/meson.html
> @@ -0,0 +1,151 @@
> +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
> +<html lang="en">
> +<head>
> +  <meta http-equiv="content-type" content="text/html; charset=utf-8">
> +  <title>Compilation and Installation using Meson</title>
> +  <link rel="stylesheet" type="text/css" href="mesa.css">
> +</head>
> +<body>
> +
> +<div class="header">
> +  <h1>The Mesa 3D Graphics Library</h1>
> +</div>
> +
> +<iframe src="contents.html"></iframe>
> +<div class="content">
> +
> +<h1>Compilation and Installation using Meson</h1>
> +
> +<h2 id="basic">1. Basic Usage</h2>
> +
> +<p><strong>The Meson build system for Mesa is still under active development,
> +and should not be used in production environments.</strong></p>
> +
> +<p>The meson build is currently only tested on linux, and is known to not work
> +on macOS, Windows, and haiku. This will be fixed.</p>
> +
> +<p>
> +The meson program is used to configure the source directory and generates
> +either a ninja build file, or Visual Studio® build files. The latter, and must
> +be enabled via the --backend switch, as ninja is always the default. Meson only
> +supports out-of-tree builds, and must be passed a directory to put built and
> +generated sources into. We'll call that directory "build" for examples.
> +</p>
> +
> +<pre>
> +    meson build/
> +</pre>
> +
> +<p>
> +To see a description of your options you can run "meson configure" along with a
> +build directory to view the selected options for. This will show your meson
> +global arguments and project arguments, along with their defaults and your
> +local settings.
> +</p>
> +
> +<pre>
> +    meson configure build/
> +</pre>
> +
> +<p>
> +With additional arguments "meson configure" is used to change options on
> +already configured build directory. All options passed to this command are in
> +the form -D"command"="value".
> +</p>
> +
> +<pre>
> +    meson configure build/ -Dprefix=/tmp/install -Dglx=true
> +</pre>
> +
> +<p>
> +Once you've run meson successfully you can use your configured backend to build
> +the project. With ninja, the -C option can be be used to point at a directory
> +to build.
> +</p>
> +
> +<pre>
> +    ninja -C build/
> +</pre>
> +
> +<p>
> +Without arguments, it will produce libGL.so and/or several other libraries
> +depending on the options you have chosen. Later, if you want to rebuild for a
> +different configuration, you should run <code>ninja clean</code> before
> +rebuilding, or create a new out of tree build directory (meson supports an
> +unlimited number of them) for each configuration you want to build.
> +</p>
> +
> +<dt><code>CC, CFLAGS, CXX, CXXFLAGS</code></dt>
> +<dd><p>These environment variables
> +control the C and C++ compilers used during the build. The default compilers
> +depends on your operating system. Meson supports most of the popular compilers,
> +a complete list is available
> +<a href="http://mesonbuild.com/Reference-tables.html#compiler-ids">here</a>.
> +
> +These arguments are consumed and stored by meson when it is initialized or
> +re-initialized. Therefore passing them to meson configure will not do anything,
> +and passing them to ninja will only do something if ninja decides to
> +re-initialze meson, for example, if a meson.build file has been changed.
> +Changing these variables will not cause all targets to be rebuilt, so running
> +ninja clean is recomended when changing CFLAGS or CXXFLAGS. meson will never
> +change compiler in a configured build directory.
> +</p>
> +
> +<pre>
> +    CC=clang CXX=clang++ meson build-clang
> +    ninja -C build-clang
> +    ninja -C build-clang clean
> +    touch meson.build
> +    CFLAGS=-Wno-typedef-redefinition ninja -C build-clang
> +</pre>
> +</dd>
> +
> +<dt><code>LLVM</code></dt>
> +<dd><p>Meson includes upstream logic to wrap llvm-config using it's standard
> +dependncy interface. It will search $PATH (or %PATH% on windows) for
> +llvm-config, so using an LLVM from a non-standard path is as easy as
> +<code>PATH=/path/with/llvm-config:$PATH meson build</code>.
> +</p></dd>
> +</dl>
> +
> +<dt><code>PKG_CONFIG_PATH</code></dt>
> +<dd><p>The
> +<code>pkg-config</code> utility is a hard requirement for configuring and
> +building Mesa on Linux and *BSD. It is used to search for external libraries
> +on the system. This environment variable is used to control the search
> +path for <code>pkg-config</code>. For instance, setting
> +<code>PKG_CONFIG_PATH=/usr/X11R6/lib/pkgconfig</code> will search for
> +package metadata in <code>/usr/X11R6</code> before the standard
> +directories.</p>
> +</dd>
> +</dl>
> +
> +<p>
> +One of the oddities of meson is that some options are different when passed to
> +the <code>meson</code> than to <code>meson configure</code>. These options are
> +passed as --option=foo to <code>meson</code>, but -Doption=foo to <code>meson
> +configure</code>. Mesa defined options are always passed as -Doption=foo.
> +<p>
> +
> +<p>For those coming from autotools be aware of the following:</p>
> +
> +<dl>
> +<dt><code>--buildtype/-Dbuildtype</code></dt>
> +<dd><p>This option will set the compiler debug/optimisation levels to aid
> +debugging the Mesa libraries.</p>
> +
> +<p>Note that in meson this defaults to "debugoptimized", and  not setting it to
> +"release" will yield non-optimal performance and binary size.</p>
> +
> +<p> For those wishing to pass their own -O option, use the "plain" buildtype,
> +which cuases meson to inject no additional compiler arguments, only those in
> +the C/CXXFLAGS and those that mesa itself defines.</p>
> +</dd>
> +</dl>
> +
> +<dl>
> +<dt><code>-Db_ndebug</code></dt>
> +<dd><p>This option controls assertions in meson projects. When set to false
> +(the default) assertions are enabled, when set to true they are disabled.</p>
> +</dd>
> +</dl>
> 