source: general/prog/rust.xml@ b112f043

<?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.xz">
  <!ENTITY rust-download-ftp  " ">
  <!ENTITY rust-md5sum        "96b082a8b44707eafa9d696923f40c28">
  <!ENTITY rust-size          "136 MB">
  <!ENTITY rust-buildsize     "9.1 GB (323 MB installed); add 6.2 GB if running the tests">
  <!ENTITY rust-time          "17 SBU (including download time; add 23 SBU for tests, both on a 4-core machine)">
]>

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


  <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, is at the moment only required
      by a few packages in this book, and particularly because newer versions
      tend to break older mozilla packages, 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 a package 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 at the start of the build, so you cannot compile it without an
      Internet connection.
    </para>

    <note>
      <para>
        Although BLFS usually installs in <filename
        class="directory">/usr</filename>, when you later upgrade to a newer
        version of <application>rust</application> the old libraries in <filename
        class="directory">/usr/lib/rustlib</filename> will remain, with various
        hashes in their names, but will not be usable and will waste space. The
        editors recommend placing the files in the <filename
        class="directory">/opt</filename> directory.  In particular, if you
        have reason to rebuild with a modified configuration (e.g. using the
        shipped LLVM after building with shared LLVM, perhaps to compile crates
        for architectures which the BLFS LLVM build does not support)
        it is possible for the install to leave a broken
        <command>cargo</command> program. In such a situation, either remove
        the existing installation first, or use a different prefix such as
        /opt/rustc-&rust-version;-build2.
      </para>

      <para>
        If you prefer, you can of course change the prefix to <filename
        class="directory">/usr</filename>.
      </para>
    </note>

    <para>
      The current <application>rustbuild</application> build-system will use
      all processors, although it does not scale well and often falls
      back to just using one core while waiting for a library to compile.
      However it can be mostly limited to a specified number of processors by
      a combination of adding the switch <literal>--jobs &lt;N&gt;</literal>
      (e.g. '--jobs 4' to limit to 4 processors) on each invocation of
      <command>python3 ./x.py</command> <emphasis>and</emphasis> using an
      environment variable <envar>CARGO_BUILD_JOBS=&lt;N&gt;</envar>. At the
      moment this is not effective when some of the rustc tests are run.
    </para>

    <para>
      The current version of rust's num_cpus crate now recognizes that cgroups
      can be used to restrict which processors it is allowed to use. So if your
      machine lacks DRAM (typically, less than 2GB DRAM per core) that might be
      an alternative to taking CPUs offline.
      <phrase revision="sysv">In sysv systems cgroups requires <ulink
      url="https://sourceforge.net/projects/libcg/">libcgroup</ulink>.</phrase>
      <phrase revision="systemd">That can be achieved by using
      <command>systemd-run</command> command with
      <parameter>-p User=$(whoami)</parameter> and
      <parameter>-p AllowedCPUs=0-<replaceable>x</replaceable></parameter>
      (with <replaceable>x</replaceable> replaced with the number of CPU
      cores you want to use minus one) options.</phrase>
    </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>
        The build times of this version when repeated on the same machine are
        often reasonably consistent, but as with all compilations using
        <command>rustc</command> there can be some very slow outliers.
      </para>
    </note>

    &lfs112_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">Additional Downloads</bridgehead>
    <itemizedlist spacing="compact">
      <listitem>
        <para>
          Required patch:
          <ulink url="&patch-root;/rustc-&rust-version;-llvm9_fixes-1.patch"/>
        </para>
      </listitem>
    </itemizedlist>-->

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

    <bridgehead renderas="sect4">Required</bridgehead>
    <para role="required">
      <xref linkend="cmake"/>
    </para>

    <bridgehead renderas="sect4">Recommended</bridgehead>
    <para role="recommended">
      <xref linkend="curl"/>,
      <xref linkend="libssh2"/>, and
      <xref linkend="llvm"/>
      (built with -DLLVM_LINK_LLVM_DYLIB=ON so that rust can link to
      system LLVM instead of building its shipped version)
    </para>

    <note>
      <para>
        If a recommended dependency is not installed, a shipped copy in the
        Rustc source tarball will be built and used.
      </para>
    </note>

    <bridgehead renderas="sect4">Optional</bridgehead>
    <para role="optional">
      <xref linkend="gdb"/> (used by the test suite if it is present) and
      <ulink url='https://libgit2.org/'>libgit2</ulink>
    </para>

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

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

    <note>
      <para>
        Currently Rust compiler produces SSE2 instructions for 32-bit x86,
        causing the generated code broken on 32-bit systems without a
        SSE2-capable processor.  All x86 processor models released after
        2004 should be SSE2-capable.  Run
        <command>lscpu | grep sse2</command> as a test.  If it outputs
        anything, your CPU is SSE2-capable and OK.  Otherwise you may try
        to build this package <emphasis>on a SSE2-capable system</emphasis>
        with the following fix applied:
      </para>

      <!-- computeroutput used deliberately to stop anyone from copying
           blindly -->
<screen role="nodump"><computeroutput>sed 's@pentium4@pentiumpro@' -i \
    compiler/rustc_target/src/spec/i686_unknown_linux_gnu.rs</computeroutput></screen>

      <para>
        And copy the resulting
        <filename class="directory">/opt/rustc-&rust-version;</filename>
        to the system without SSE2 capability. But this change is still
        under upstream review and not tested by BLFS editors.
      </para>
    </note>

    <para>
      To install into the
      <filename class="directory">/opt</filename> directory, remove any
      existing <filename>/opt/rustc</filename> symlink
      and create a new directory (i.e. with a different name if trying a
      modified build of the same version).
      As the <systemitem class="username">root</systemitem>
      user:
    </para>

<screen role="root"><userinput>mkdir /opt/rustc-&rust-version;         &amp;&amp;
ln -svfn rustc-&rust-version; /opt/rustc</userinput></screen>

    <note>
      <para>
        If multiple versions of <application>Rust</application> are installed
        in <filename class="directory">/opt</filename>, changing to another
        version only requires changing the <filename> /opt/rustc</filename>
        symbolic link and then running <command>ldconfig</command>.
      </para>
    </note>

    <para>
      Create a suitable <filename>config.toml</filename> file which will
      configure the build.
    </para>

<screen><userinput>cat &lt;&lt; EOF &gt; config.toml
<literal># see config.toml.example for more possible options
# See the 8.4 book for an old example using shipped LLVM
# e.g. if not installing clang, or using a version before 13.0

# tell x.py to not keep printing an annoying warning
changelog-seen = 2

[llvm]
# by default, rust will build for a myriad of architectures
targets = "X86"

# When using system llvm prefer shared libraries
link-shared = true

[build]
# omit docs to save time and space (default is to build them)
docs = false

# install extended tools: cargo, clippy, etc
extended = true

# Do not query new versions of dependencies online.
locked-deps = true

# Specify which extended tools (those from the default install).
tools = ["cargo", "clippy", "rustfmt"]

# Use the source code shipped in the tarball for the dependencies.
# The combination of this and the "locked-deps" entry avoids downloading
# many crates from Internet, and makes the Rustc build more stable.
vendor = true

[install]
prefix = "/opt/rustc-&rust-version;"
docdir = "share/doc/rustc-&rust-version;"

[rust]
channel = "stable"
description = "for BLFS &version;"

# BLFS used to not install the FileCheck executable from llvm,
# so disabled codegen tests.  The assembly tests rely on FileCheck
# and cannot easily be disabled, so those will anyway fail if
# FileCheck has not been installed.
#codegen-tests = false

[target.x86_64-unknown-linux-gnu]
# NB the output of llvm-config (i.e. help options) may be
# dumped to the screen when config.toml is parsed.
llvm-config = "/usr/bin/llvm-config"

[target.i686-unknown-linux-gnu]
# NB the output of llvm-config (i.e. help options) may be
# dumped to the screen when config.toml is parsed.
llvm-config = "/usr/bin/llvm-config"

</literal>
EOF</userinput></screen>

<!--<para>
     Adapt rustc to allow it to build and function with the changes in LLVM-9:
    </para>

<screen><userinput remap="pre">patch -Np1 -i ../rustc-&rust-version;-llvm9_fixes-1.patch</userinput></screen>-->

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

<!-- fixed in 1.58.0, retain as a reminder that fixed crates can be used
<screen><userinput>sed -i -e '/^curl /s/0.4.38/0.4.40/' \
       -e '/^curl-sys /s/0.4.48/0.4.50/' \
       src/tools/cargo/Cargo.toml &amp;&amp; -->

<screen><userinput>{ [ ! -e /usr/include/libssh2.h ] ||
  export LIBSSH2_SYS_USE_PKG_CONFIG=1; } &amp;&amp;
python3 ./x.py build</userinput></screen>

    <note>
      <para>
        The test suite 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.
      </para>
    </note>

    <para>
      To run the tests (again using all available CPUs) issue:
    </para>

<screen remap="test"><userinput>python3 ./x.py test --verbose --no-fail-fast | tee rustc-testlog</userinput></screen>

    <para>
      If <command>FileCheck</command> from <application>LLVM</application> has
      not been installed, all 47 tests from the <quote>assembly</quote> suite
      will fail.
    </para>

    <para>
      As with all large test suites, other tests might fail on some machines -
      if the number of additional failures is in the single digits,
      check the log for 'failures:' and review lines above that, particularly the
      'stderr:' lines. Any mention of
      SIGSEGV or signal 11 in a failing test is a cause for concern.
    </para>

    <para>
      If you get any <emphasis>other</emphasis> failing test which reports an
      issue number then you should search for that issue.  For example, when
      rustc &gt;= 1.41.1 was built with a version of sysllvm before 10.0 the test
      for issue 69225 failed <ulink
      url="https://github.com/rust-lang/rust/issues/69225"/> and that should be
      regarded as a critical failure (they released 1.41.1 because of it).
      Most other failures will not be critical.
    </para>

    <para>
      Therefore, you should determine the number of failures.
    </para>

    <para>
      The number of tests which passed and failed can be found by running:
    </para>

<!-- split into two lines for narrower screen windows -->
<screen remap="test"><userinput>grep '^test result:' rustc-testlog |
 awk '{sum1 += $4; sum2 += $6} END { print sum1 " passed; " sum2 " failed" }'</userinput></screen>

    <para>
      The other available fields are $8 for those which were ignored
      (i.e. skipped),  $10 for 'measured' and $12 for 'filtered out' but both
      those last two are probably zero.
    </para>

    <para>
      Now, as the &root; user, install the package:
    </para>

<screen role='root'><userinput>python3 ./x.py install</userinput></screen>

  </sect2>

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

    <para>
      <command>ln -svfn rustc-&rust-version; /opt/rustc</command>: if this is
      not the first use of the <filename class="directory">/opt/rustc</filename>
      symlink, overwrite it by forcing, and use the '-n' flag to avoid getting
      confusing results from e.g. <command>ls -l</command>.
    </para>

    <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">/opt/rustc/lib/src</filename>.
    </para>

    <para>
      <command>extended = true</command>: this installs several tools
      (specified by the <literal>tools</literal> entry) alongside
      <command>rustc</command>.
    </para>

    <para>
      <command>tools = ["cargo", "clippy", "rustfmt"]</command>: if the tools
      are not scecified, the absence of <application>Miri</application> now
      causes the install to fail. But <application>Miri</application> is not
      built in the stable channel. Some of the other tools are unlikely to
      be useful unless using (old) code analyzers or editing the standard library.
      This set match those from the 'default' profile in binary command
      <command>rustup</command> which are recommended for most users, except that
      the documentation was disabled at the start of the '[build]' section.
    </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>

    <!-- 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>sed -i -e '/^curl /s/0.4.38/0.4.40/' ... </command>: two crates
      normally downloaded for this release do not correctly initialise
      <application>curl</application> if using
      <application>openssl-3.0.0</application>. Upstream has fixed that for a
      future release, this sed causes the fixed versions to be used.
    </para>-->

    <!-- https://github.com/alexcrichton/ssh2-rs/issues/173 -->
    <para>
      <command>export LIBSSH2_SYS_USE_PKG_CONFIG=1</command>: Allow
      <command>cargo</command> to link to system libssh2.
    </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.
      2023-01-14 : assumed to be no longer needed, but it is some years
      since one person reported needing this, keep it commented for the moment.
    </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 test suite
      will not stop at the first error.
    </para>

  </sect2>

  <sect2 role="configuration">
    <title>Configuring Rust</title>

    <sect3 id="rustc-config">
      <title>Configuration Information</title>

      <para>
        If you installed <application>rustc</application> in
        <filename class="directory">/opt</filename>, you need to update the
        following configuration files so that <application>rustc</application>
        is correctly found by other packages and system processes.
      </para>

      <para>
        As the <systemitem class="username">root</systemitem> user, create
        the <filename>/etc/profile.d/rustc.sh</filename> file:
      </para>

<screen role="root"><userinput>cat &gt; /etc/profile.d/rustc.sh &lt;&lt; "EOF"
<literal># Begin /etc/profile.d/rustc.sh

pathprepend /opt/rustc/bin           PATH

# Include /opt/rustc/man in the MANPATH variable to access manual pages
pathappend  /opt/rustc/share/man     MANPATH

# End /etc/profile.d/rustc.sh</literal>
EOF</userinput></screen>

      <para>
        Immediately after installation, update the current PATH
        for your current shell as a normal user:
      </para>

<screen><userinput>source /etc/profile.d/rustc.sh</userinput></screen>

    </sect3>
  </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, rust-gdb,
          rust-gdbgui, rust-lldb, rustc, rustdoc, and rustfmt
        </seg>
        <seg>
          librustc-driver-&lt;16-byte-hash&gt;.so,
          libstd-&lt;16-byte-hash&gt;.so, and
          libtest-&lt;16-byte-hash&gt;.so
        </seg>
        <seg>
          ~/.cargo,
          /opt/rustc, symbolic link to
          /opt/rustc-&rust-version;
        </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-miri">
        <term><command>cargo-miri</command></term>
        <listitem>
          <para>
            is for use by Miri to interpret bin crates and tests. It is
            not installed by default.
          </para>
          <indexterm zone="rust cargo-miri">
            <primary sortas="b-cargo-miri">cargo-miri</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="miri">
        <term><command>miri</command></term>
        <listitem>
          <para>
            is an interpreter for Rust's mid-level intermediate representation
            (MIR). It is not installed by default.
          </para>
          <indexterm zone="rust miri">
            <primary sortas="b-miri">miri</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-analyzer">
        <term><command>rust-analyzer</command></term>
        <listitem>
          <para>
            is an implementation of Language Server Protocol for the Rust
            programming language.
          </para>
          <indexterm zone="rust rust-analyzer">
            <primary sortas="b-rust-analyzer">rust-analyzer</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="rust-demangler">
        <term><command>rust-demangler</command></term>
        <listitem>
          <para>
            converts a list of Rust mangled symbols into a
            corresponding list of demangled symbols
          </para>
          <indexterm zone="rust rust-demangler">
            <primary sortas="b-rust-demangler">rust-demangler</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">/opt/rustc-&rust-version;/lib/rustlib/etc</filename>
          </para>
          <indexterm zone="rust rust-gdb">
            <primary sortas="b-rust-gdb">rust-gdb</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="rust-gdbgui">
        <term><command>rust-gdbgui</command></term>
        <listitem>
          <para>
            is a wrapper script for a graphical front end to gdb that runs in a
            browser
          </para>
          <indexterm zone="rust rust-gdbgui">
            <primary sortas="b-rust-gdbgui">rust-gdbgui</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>