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

Wed Oct 18 17:27:23 UTC 2017

Quoting Emil Velikov (2017-10-18 03:32:14)
> On 17 October 2017 at 20:21, Dylan Baker <dylan at pnwbakers.com> wrote:
> > Signed-off-by: Dylan Baker <dylanx.c.baker at intel.com>
> > ---
> >
> > I'm sending this out now so that others can look at it, review it, and reference
> > it, but this should not end up in the 17.3 release, as the meson build for mesa
> > will not be ready to go into the 17.3 release.
> >
> >  docs/contents.html |  1 +
> >  docs/meson.html    | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  2 files changed, 100 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..f45a62c9da4
> > --- /dev/null
> > +++ b/docs/meson.html
> > @@ -0,0 +1,99 @@
> > +<!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>
> > +The meson program is used to configure the source directory and generates
> > +either a ninja build file, or visual studio build files.
> 
> s/The meson Visual Studio® backend is only available on Microsoft®
> Windows®, and/The latter
> 
> > 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". This will
> > +show your meson project configuration options as well as your local
> > +configuration options. One meson option to be aware of is that meson's default
> > +build type is "debug" (-O0 -g on gcc/clang).
> 
> Is `meson configure' only for viewing or can it be used to amend existing setup?
> Hunk says the former, follow-up reply to Nicolai implies the latter.

Both, and I believe that's fixed in the updated version on my github, but I'll
double check.

> 
> 
> > +</p>
> > +
> > +<pre>
> > +    meson configure build
> > +</pre>
> > +
> > +Once you're run meson successfully you can use your configured backend to build
> > +the project, for Linux/*BSD and macOS that will be ninja. If you're unfamiliar
> > +with ninja, it automatically detects your CPU's and sets it's jobs
> > +appropriately. The -C option allows us to point ninja at the build directory
> > +without changing into it.
> Pretty sure one can lookup ninja if they need to ;-)  I'd slim down
> the lot to something like:
> 
> Once you've run meson successfully you can use your configured backend to build
> the project. In case of ninja, the -C option should point at the build
> directory.
> 
> > +
> > +<pre>
> > +    ninja -C build
> > +</pre>
> > +
> > +<p>
> > +This 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 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 GCC, Clang, and MSVC as first
> > +class compilers. There is some support for the Intel ICC compiler. No other
> > +C/C++ compilers are currently supported.
> The list will be outdated state too often, so I'd swap it with a link
> to Meson's docs.
> 
> Meson supports various compilers see $link_to_meson_documentation

Fair point.

> 
> 
> > +</dd>
> > +
> > +<dt><code>PKG_CONFIG_PATH</code></dt>
> > +<dd><p>The
> > +<code>pkg-config</code> utility is a hard requirement for configuring and
> > +building mesa. 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 initial meson step than to meson configure. These options are passed as
> > +--option=foo to meson, but -Doption=foo to meson configure. Project defined
> > +options are always passed as -Doption=foo.
> It took me a few reads to parse this one. Some formatting suggestions.
> 
> Oddities of meson:
>  - Some options are different when passed to <code>meson</code> vs
> <code>meson configure</code>.
> Namely: the former tends to use ..... while the latter ...
> // XXX: Worth adding a table and/or link to the Meson docs?
> <strong>Note:</strong> Project defined options ....

Yeah, there's probably something in the meson docs about this. For your
information, basically all of the standard autotools options are passed as
--option: prefix, libdir, bindir, etc.

> 
> > +<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 (if the user
> > +hasn't already set them via the CFLAGS/CXXFLAGS) and macros to aid in
> > +debugging the Mesa libraries.</p>
> > +
> > +<p>Note that in meson this defaults to "debug", and  not setting it to
> > +"release" will yield non-optimal performance and binary size</p>
> Ouch, can we change that?

When I did an informal poll in the Intel cube the universal consensus was that
defaulting to debug was a feature. If the wider community disagrees, yes, it can be
changed.

I'll fix up the other stuff too.

Dylan
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