source: general/prog/rust.xml@ 07a48bb

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../../general.ent">
  %general-entities;

  <!ENTITY rust-download-http "https://static.rust-lang.org/dist/rustc-&rust-version;-src.tar.gz">
  <!ENTITY rust-download-ftp  " ">
  <!ENTITY rust-md5sum        "366f049777e00d0d6f15d25895485efb">
  <!ENTITY rust-size          "152 MB">
  <!-- Gentle Reminder: buildsize is how much the user requires for the real
       install, i.e. the source with its DESTDIR *plus* the DESTDIR.  You
       can 'mkdir /tmp/RUST ; cp -a install/* /tmp/RUST' and then run 'du -sch'
       to measure it. -->

  <!ENTITY rust-buildsize     "6.2 GB (475 MB installed) including 295MB of ~/.cargo files for the user building this. Add 1.5GB if installing the documentation (an extra 314MB is installed), and 2.0GB if running the tests">
  <!ENTITY rust-time          "34 SBU (add 3 SBU if installing the documentation and 15 SBU for tests, both with 4 processors)">
]>

<sect1 id="rust" xreflabel="rustc-&rust-version;">
  <?dbhtml filename="rust.html"?>

  <sect1info>
    <othername>$LastChangedBy$</othername>
    <date>$Date$</date>
  </sect1info>

  <title>Rustc-&rust-version;</title>

  <indexterm zone="rust">
    <primary sortas="a-rust">Rust</primary>
  </indexterm>

  <sect2 role="package">
    <title>Introduction to Rust</title>

    <para>
      The <application>Rust</application> programming language is designed
      to be a safe, concurrent, practical language.
    </para>

    <para>
      This package is updated on a six-weekly release cycle. Because it is
      such a large and slow package to build, and is at the moment only required
      by five packages in this book, the BLFS editors take the view that it
      should only be updated when that is necessary (either to fix problems,
      or to allow a new version of <application>firefox</application> to build).
    </para>

    <para>
      As with many  other programming languages, rustc (the rust compiler)
      needs a binary from which to bootstrap. It will download a stage0 binary
      and many cargo crates (these are actually .tar.gz source archives) at
      the start of the build, so you cannot compile it without an internet
      connection.
    </para>

    <para>
      These crates will then remain in various forms (cache, directories of
      extracted source), in <filename class="directory">~/.cargo</filename> for
      ever more. It is common for large <application>rust</application> packages
      to use multiple versions of some crates. If you purge the files before
      updating this package, very few crates will need to be updated by the
      packages in this book which use it (and they will be downloaded as
      required). But if you retain an older version as a fallback option and
      then use it (that would require <emphasis>not</emphasis> building in
      <filename class="directory">/usr</filename>), it is likely that it will
      then have to re download some crates. For a full download (i.e. starting
      with an empty or missing <filename class="directory">~/.cargo</filename>)
      downloading the external cargo files for this version only takes a minute
      or so on a fast network.
    </para>

    <note>
      <para>
        When you upgrade to a newer version, the new libraries will have various
        hashes in their names and therefore there will be a mix of versions but
        only one of each will be usable. A binary distribution would use its
        package manager to delete all the old <application>rust</application>
        installation before updating. You may wish to do the same to save space.
      </para>
    </note>

    <para>
      The current <application>rustbuild</application> build-system will use
      all available processors, although it does not scale well and often falls
      back to just using one core while waiting for a library to compile.
    </para>

    <para>
      At the moment <application>Rust</application> does not provide any
      guarantees of a stable ABI.
    </para>

    <note>
      <para>
        Rustc defaults to building for ALL supported architectures, using a
        shipped copy of LLVM. In BLFS the build is only for the X86 architecture.
        If you
        intend to develop rust crates, this build may not be good enough for your
        purposes.
      </para>
      <para>
        Unlike with previous versions, the build times of this version when
       repeated on the same machine seem reasonably consistent.
      </para>
      <para>
        Unusually, a DESTDIR-style method is being used to install this package.
        This is because running the install as root not only downloads all of the
        cargo files again (to <filename>/root/.cargo</filename>), it then spends
        a very long time recompiling. Using this method saves a lot of time, at
        the cost of extra disk space.
      </para>
    </note>

    &lfs83_checked;

    <bridgehead renderas="sect3">Package Information</bridgehead>
    <itemizedlist spacing="compact">
      <listitem>
        <para>
          Download (HTTP): <ulink url="&rust-download-http;"/>
        </para>
      </listitem>
      <listitem>
        <para>
          Download (FTP): <ulink url="&rust-download-ftp;"/>
        </para>
      </listitem>
      <listitem>
        <para>
          Download MD5 sum: &rust-md5sum;
        </para>
      </listitem>
      <listitem>
        <para>
          Download size: &rust-size;
        </para>
      </listitem>
      <listitem>
        <para>
          Estimated disk space required: &rust-buildsize;
        </para>
      </listitem>
      <listitem>
        <para>
          Estimated build time: &rust-time;
        </para>
      </listitem>
    </itemizedlist>

    <bridgehead renderas="sect3">Rust Dependencies</bridgehead>

    <bridgehead renderas="sect4">Required</bridgehead>
    <para role="required">
      <xref linkend="curl"/>,
      <xref linkend="cmake"/>,
      <xref linkend="libssh2"/>, and
      <xref linkend="python2"/>
    </para>

<!-- comment out while using shipped LLVM
    <bridgehead renderas="sect4">Recommended</bridgehead>
    <para role="recommended">
      <package>clang</package> from <xref linkend="llvm"/>
      (built with -DLLVM_LINK_LLVM_DYLIB=ON)
    </para>-->

    <bridgehead renderas="sect4">Optional</bridgehead>
    <para role="optional">
      <xref linkend="gdb"/> (used by the testsuite if it is present)
    </para>

    <para condition="html" role="usernotes">
      User Notes: <ulink url="&blfs-wiki;/rust"/>
    </para>
  </sect2>

  <sect2 role="installation">
    <title>Installation of Rust</title>

    <para>
      First create a suitable <filename>config.toml</filename> file which will
      configure the build. Unlike with previous releases, where even quite old
      system versions of <application>LLVM</application>worked well, this
      version ships with a development version and using the current <xref
      linkend="llvm"/> release is known to result in breakage in some
      circumstances.
    </para>

<screen><userinput>cat &lt;&lt; EOF &gt; config.toml
# see config.toml.example for more possible options
[llvm]

# use ninja
ninja = true

targets = "X86"
# When compiling LLVM, the experimental targets (WebAssembly
# and RISCV) are built by default - omit them
experimental-targets = ""

[build]
# omit HTML docs to save time and space (comment this to build them)
docs = false

# install cargo as well as rust
extended = true

[install]
prefix = "/usr"
# docdir is used even if the full awesome docs are not installed
docdir = "share/doc/rustc-&rust-version;"

[rust]
channel = "stable"
rpath = false

# BLFS does not install the FileCheck executable from llvm,
# so disable codegen tests
codegen-tests = false

# get a trace if there is an Internal Compiler Exception
backtrace-on-ice = true

EOF</userinput></screen>

    <para>
      Now install <application>Rust</application> by running the following
      commands:
    </para>

<screen><userinput>export RUSTFLAGS="$RUSTFLAGS -C link-args=-lffi" &amp;&amp;
./x.py build --exclude src/tools/miri</userinput></screen>

    <note>
      <para>
        The testsuite will generate some messages in the
        <phrase revision="sysv">system log</phrase>
        <phrase revision="systemd">systemd journal</phrase>
        for traps on invalid opcodes, and for segmentation faults.
        In themselves these are nothing to worry about, just a way for the
        test to be terminated. But if the output from the testsuite reports tests
        which FAIL with segmentation faults (signal 11) then there may be a
        problem.
      </para>
    </note>

    <para>
      To run the tests issue
      <command>./x.py test --verbose --no-fail-fast | tee rustc-testlog</command>:
      as with the build, that will use all available CPUs.
    </para>

    <para>
      The instructions above do not build ARM compilers, so the testsuite
      <emphasis>will</emphasis> fail and the tests will be reported to end in
      error, with a backtrace of the last failing test. On a good run, 3 tests
      which need Thumb (ARM) compilers will fail, all  in <filename
      class="directory">ui/issues</filename> for issues 37131, 49851 and 50993.
      Occasionally a fourth test, in run-make, 'sysroot-crates-are-unstable',
      has been known to fail.  That is probably harmless. As with all large
      testsuites, other tests might fail on some machines - if the number of
      failures is in the single digits, check the log for 'FAILED' and review
      lines above that. Any mention of SIGSEGV or signal 11 in a failing test
      is a cause for concern.
    </para>

    <para>
      Therefore, you should determine the number of tests, failures, etc. The
      total number of tests which were considered is found by running:
    </para>

<screen><command>grep 'running .* tests' rustc-testlog | awk '{ sum += $2 } END { print sum }'</command></screen>

    <para>
      That should report 15795 tests. Similarly, the total tests which failed can
      be found by running:
    </para>

<screen><command>grep '^test result:' rustc-testlog | awk  '{ sum += $6 } END { print sum }'</command></screen>

    <para>
      And similarly for the tests which passed use $4, for those which were ignored
      (i.e. skipped) use $8 (and $10 for 'measured', $12 for 'filtered out' but both
      are probably zero). The breakdown does not quite match the overall total.
    </para>

    <para>
      Still as your normal user, do a DESTDIR install:
    </para>

<screen><userinput>export LIBSSH2_SYS_USE_PKG_CONFIG=1 &amp;&amp;
DESTDIR=${PWD}/install ./x.py install &amp;&amp;
unset LIBSSH2_SYS_USE_PKG_CONFIG</userinput></screen>

    <para>
      Now, as the <systemitem class="username">root</systemitem> user
      install the files from the DESTDIR:
    </para>

<screen role="root"><userinput>chown -R root:root install &amp;&amp;
cp -a install/* /</userinput></screen>

  </sect2>

  <sect2 role="commands">
    <title>Command Explanations</title>

    <para>
      <command>targets = "X86"</command>: this avoids building all the available
      linux cross-compilers (Aarch64, MIPS, PowerPC, SystemZ, etc). Unfortunately,
      rust insists on installing source files for these below
      <filename class="directory">/usr/lib/rustlib/src</filename>.
    </para>

    <para>
      <command>extended = true</command>: this installs Cargo alongside Rust.
    </para>

    <para>
      <command>channel = "stable"</command>: this ensures only stable features
      can be used, the default in <filename>config.toml</filename> is to use
      development features, which is not appropriate for a released version.
    </para>

    <para>
      <command>rpath = false</command>: by default, <command>rust</command> can
      be run from where it was built, without being installed. That adds DT_RPATH
      entries to all of the ELF files, which produces very messy output from
      <command>ldd</command>, showing the libraries in the place they were built,
      even if they have been deleted from there after the install.
    </para>

    <!-- comment while using shipped LLVM
    <para>
      <command>[target.x86_64-unknown-linux-gnu]</command>: the syntax of
      <filename>config.toml</filename> requires an <literal>llvm-config</literal>
      entry for each target for which system-llvm is to be used. Change the target
      to <literal>[target.i686-unknown-linux-gnu]</literal> if you are building
      on 32-bit x86. This whole section may be omitted if you wish to build
      against the shipped llvm, or do not have clang, but the resulting build will
      be larger and take longer.
    </para>-->

    <para>
      <command>export RUSTFLAGS="$RUSTFLAGS -C link-args=-lffi"</command>:
      This adds a link to libffi to any RUSTFLAGS you may already be passing
      to the build. On some systems, linking fails to include libffi unless
      this is used. The reason why this is needed is not clear.
    </para>

    <para>
      <command>--exclude src/tools/miri</command>: For a long time, the miri
      crate (an interpreter for the Midlevel Intermediate Representation)
      has failed to build on releases. It is optional, but the failure
      messages can persuade people that the whole build failed.
    </para>

    <para>
      <command>--verbose</command>: this switch can sometimes provide more
      information about a test which fails.
    </para>

    <para>
      <command>--no-fail-fast</command>: this switch ensures that the testsuite
      will not stop at the first error.
    </para>

    <para>
      <command>export LIBSSH2_SYS_USE_PKG_CONFIG=1</command>: On some systems,
      cairo fails to link during the install because it cannot find libssh2.
      This seems to fix it, but again the reason why the problem occurs is not
      understood.
    </para>

    <para>
      <command>DESTDIR=${PWD}/install ./x.py install</command>: This effects a
      DESTDIR-style install in the source tree,creating an <filename
      class="directory">install</filename> directory. Note that DESTDIR installs
      need an absolute path, passing 'install' will not work.
    </para>

    <para>
      <command>chown -R root:root install</command>: the DESTDIR install
      was run by a regular user, who owns the files. For security, change their
      owner before doing a simple copy to install them.
    </para>

  </sect2>

  <sect2 role="content">
    <title>Contents</title>

    <segmentedlist>
      <segtitle>Installed Programs</segtitle>
      <segtitle>Installed Libraries</segtitle>
      <segtitle>Installed Directories</segtitle>

      <seglistitem>
        <seg>
          cargo-clippy, cargo-fmt, cargo, clippy-driver, rls, rust-gdb, rust-lldb, rustc, rustdoc, rustfmt.
        </seg>
        <seg>
          Many lib*&lt;16-byte-hash&gt;.so libraries.
        </seg>
        <seg>
          ~/.cargo,
          /usr/lib/rustlib,
          /usr/share/doc/rustc-&rust-version;, and
          /usr/share/zsh/site-functions/
        </seg>
      </seglistitem>
    </segmentedlist>

    <variablelist>
      <bridgehead renderas="sect3">Short Descriptions</bridgehead>
      <?dbfo list-presentation="list"?>
      <?dbhtml list-presentation="table"?>

      <varlistentry id="cargo-clippy">
        <term><command>cargo-clippy</command></term>
        <listitem>
          <para>
            provides lint checks for a cargo package.
          </para>
          <indexterm zone="rust cargo-clippy">
            <primary sortas="b-cargo-clippy">cargo-clippy</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="cargo-fmt">
        <term><command>cargo-fmt</command></term>
        <listitem>
          <para>
            formats all bin and lib files of the current crate using
            rustfmt.
          </para>
          <indexterm zone="rust cargo-fmt">
            <primary sortas="b-cargo-fmt">cargo-fmt</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="cargo">
        <term><command>cargo</command></term>
        <listitem>
          <para>
            is the Package Manager for Rust.
          </para>
          <indexterm zone="rust cargo">
            <primary sortas="b-cargo">cargo</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="clippy-driver">
        <term><command>clippy-driver</command></term>
        <listitem>
          <para>
            provides lint checks for Rust.
          </para>
          <indexterm zone="rust clippy-driver">
            <primary sortas="b-clippy-driver">clippy-driver</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="rls">
        <term><command>rls</command></term>
        <listitem>
          <para>
            is the Rust Language Server. This can run in the background to
            provide IDEs, editors, and other tools with information about Rust
            programs.
          </para>
          <indexterm zone="rust rls">
            <primary sortas="b-rls">rls</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="rust-gdb">
        <term><command>rust-gdb</command></term>
        <listitem>
          <para>
            is a wrapper script for gdb, pulling in Python
            pretty-printing modules installed in <filename
            class="directory">/usr/lib/rustlib/etc</filename>.
          </para>
          <indexterm zone="rust rust-gdb">
            <primary sortas="b-rust-gdb">rust-gdb</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="rust-lldb">
        <term><command>rust-lldb</command></term>
        <listitem>
          <para>
            is a wrapper script for LLDB (the LLVM debugger)
            pulling in the Python pretty-printing modules.
          </para>
          <indexterm zone="rust rust-lldb">
            <primary sortas="b-rust-lldb">rust=lldb</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="rustc">
        <term><command>rustc</command></term>
        <listitem>
          <para>
            is the rust compiler.
          </para>
          <indexterm zone="rust rustc">
            <primary sortas="b-rustc">rustc</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="rustdoc">
        <term><command>rustdoc</command></term>
        <listitem>
          <para>
            generates documentation from rust source code.
          </para>
          <indexterm zone="rust rustdoc">
            <primary sortas="b-rustdoc">rustdoc</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="rustfmt">
        <term><command>rustfmt</command></term>
        <listitem>
          <para>
            formats rust code.
          </para>
          <indexterm zone="rust rustfmt">
            <primary sortas="b-rustfmt">rustfmt</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="libstd">
        <term><filename class="libraryfile">libstd-&lt;16-byte-hash&gt;.so</filename></term>
        <listitem>
          <para>
            is the Rust Standard Library, the foundation of portable Rust software.
          </para>
          <indexterm zone="rust libstd">
            <primary sortas="c-libstd">libstd-&lt;16-byte-hash&gt;.so</primary>
          </indexterm>
        </listitem>
      </varlistentry>
    </variablelist>
  </sect2>
</sect1>