glfs/general/prog/gcc.xml

<?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 gcc-download-http  "&gnu-http;/gcc/gcc-&gcc-version;/gcc-&gcc-version;.tar.xz">
  <!ENTITY gcc-download-ftp   "&gnu-ftp;/gcc/gcc-&gcc-version;/gcc-&gcc-version;.tar.xz">
  <!ENTITY gcc-md5sum         "be2da21680f27624f3a87055c4ba5af2">
  <!ENTITY gcc-size           "59 MB">
  <!ENTITY gcc-buildsize      "7.6 GB (with tests)">
  <!ENTITY gcc-time           "55 SBU (with tests and parallelism=4)">
]>

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

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

  <title>GCC-&gcc-version;</title>

  <indexterm zone="gcc">
    <primary sortas="a-gcc-5-0">GCC-&gcc-version;</primary>
  </indexterm>

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

    <para>
      The <application>GCC</application> package contains the GNU Compiler
      Collection. This page describes the installation of compilers for the
      following languages: C, C++, Fortran, Objective C, Objective C++, and Go.
      One additional language, Ada, is available in the collection. It has
      specific requirements, so it is described in a separate page (<xref
      linkend="gcc-ada"/>). Since C and C++ are installed in LFS, this page is
      either for upgrading C and C++, or for installing additional compilers.
    </para>

    &lfs82_checked;

    <caution>
      <para>
        If you are upgrading <application>GCC</application> from any other
        version prior to &gcc-version;, then you must be careful compiling 3rd
        party kernel modules. You should ensure that the kernel and all its
        native modules are also compiled using the same version of
        <application>GCC</application> that you use to build the 3rd party module.
        This issue does not affect native kernel (and kernel modules) updates,
        as the instructions below are a complete reinstallation of
        <application>GCC</application>. If you have existing 3rd party modules
        installed, ensure they are recompiled using the updated version of
        <application>GCC</application>. As always, never update the kernel
        headers from the ones used when <application>Glibc</application> was
        compiled during LFS.
      </para>

      <para>
        Some system headers need to be fixed to be used with GCC. This is done
        during the installation of GCC, and the <quote>fixed</quote> headers
        are installed in <filename class="directory">
        /usr/lib/gcc/&lt;machine triplet&gt;/&lt;GCC version&gt;/include-fixed
        </filename>. This is harmless if GCC is built during the LFS stage. But
        if you reinstall GCC in BLFS, some of the BLFS packages may be
        <quote>fixed</quote>. If one of those packages is reinstalled
        afterwards, the <quote>fixed</quote> headers are not updated, which may
        lead to version mismatches. In case that happens, the
        <quote>fixed</quote> headers must be updated by running (as
        <systemitem class="username">root</systemitem>):
        <command>
         /usr/libexec/gcc/x86_64-pc-linux-gnu/&gcc-version;/install-tools/mkheaders
        </command>. The machine triplet may be different on a 32bit system.
      </para>
    </caution>

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

<!--    <bridgehead renderas="sect3">Additional Downloads</bridgehead>
    <itemizedlist spacing="compact">
      <listitem>
        <para>
          Required patch:
          <ulink url="&patch-root;/gcc-&gcc-version;-upstream_fixes-1.patch"/>
        </para>
      </listitem>
    </itemizedlist>
-->

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

    <bridgehead renderas="sect4">Recommended</bridgehead>
    <para role="recommended">
      <xref linkend="dejagnu"/>, for tests
    </para>

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

  </sect2>

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

    <important>
      <para>
        Even if you specify only languages other than C and C++ to the
        <command>./configure</command> command below, the
        installation process will overwrite your existing
        <application>GCC</application> C and C++ compilers and libraries.
        Having the <application>Tcl</application>,
        <application>Expect</application> and <application>DejaGnu</application>
        packages installed before beginning the build is highly recommended so
        you can run the full suite of tests.
      </para>

      <para>
        Do not continue with the <command>make install</command> command
        until you are confident the build was successful. You can compare your
        test results with those found at <ulink
        url="http://gcc.gnu.org/ml/gcc-testresults/"/>. You may also want to
        refer to the information found in the <application>GCC</application>
        section of Chapter 6 in the LFS book (<ulink
        url="&lfs-root;/chapter06/gcc.html"/>).
      </para>
    </important>

    <para>
      The instructions below are intentionally performing a
      <quote>bootstrap</quote> process. Bootstrapping is needed for robustness
      and is highly recommended when upgrading the compilers version. To disable
      bootstrap anyways, add <parameter>--disable-bootstrap</parameter> to the
      <command>./configure</command> options below.
    </para>

    <para>
      Install <application>GCC</application> by running the following commands:
    </para>

<screen><userinput>case $(uname -m) in
  x86_64)
    sed -e '/m64=/s/lib64/lib/' \
        -i.orig gcc/config/i386/t-linux64
  ;;
esac

mkdir build                                          &amp;&amp;
cd    build                                          &amp;&amp;

../configure                                         \
    --prefix=/usr                                    \
    --disable-multilib                               \
    --with-system-zlib                               \
    --enable-languages=c,c++,fortran,go,objc,obj-c++ &amp;&amp;
make</userinput></screen>

    <para>
      If you have installed additional packages such as
      <application>Valgrind</application> and <application>GDB</application>,
      the <application>GCC</application> part of the testsuite will run more
      tests than in LFS. Some of those will report FAIL and others XPASS
      (pass when expected to FAIL). To run the tests, issue:
    </para>

<screen><userinput>ulimit -s 32768 &amp;&amp;
make -k check</userinput></screen>
<!-- The command above may error out, so using && may prevent the summary
to be run. -->

    <para>
      The tests are very long, and the results may be hard to find in the
      logs, specially if you use parallel jobs with make. You can get a summary
      of the tests with:
    </para>

<screen><userinput>../contrib/test_summary</userinput></screen>

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

<screen role="root"><userinput>make install &amp;&amp;

mkdir -pv /usr/share/gdb/auto-load/usr/lib              &amp;&amp;
mv -v /usr/lib/*gdb.py /usr/share/gdb/auto-load/usr/lib &amp;&amp;

chown -v -R root:root \
    /usr/lib/gcc/*linux-gnu/&gcc-version;/include{,-fixed}</userinput></screen>

    <para>
      Some packages expect to find the C preprocessor in
      <filename class="directory">/lib</filename> or may refer to the C compiler
      under the name <command>cc</command>. The following symbolic links are not
      needed if you have followed the LFS instructions, since they
      have been already created. If you do not have them on your system, issue
      as the <systemitem class="username">root</systemitem> user:
    </para>

<screen role="root"><userinput>ln -v -sf ../usr/bin/cpp /lib          &amp;&amp;
ln -v -sf gcc /usr/bin/cc              &amp;&amp;
install -v -dm755 /usr/lib/bfd-plugins &amp;&amp;
ln -sfv ../../libexec/gcc/$(gcc -dumpmachine)/&gcc-version;/liblto_plugin.so /usr/lib/bfd-plugins/</userinput></screen>

  </sect2>

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

    <para>
      <command>mkdir build; cd build</command>: The
      <application>GCC</application> documentation recommends
      building the package in a dedicated build directory.
    </para>

    <para>
      <parameter>--disable-multilib</parameter>: This parameter ensures
      that files are created for the specific architecture of your computer.
    </para>

    <para>
      <parameter>--with-system-zlib</parameter>: Uses the system
      <application>zlib</application> instead of the bundled one.
      <application>zlib</application> is used for compressing
      and uncompressing <application>GCC</application>'s intermediate
      language in LTO (Link Time Optimization) object files.
    </para>

    <para>
      <parameter>--enable-languages=c,c++,fortran,go,objc,obj-c++</parameter>:
      This command identifies which languages to build. You may modify
      this command to remove undesired languages. Two other languages can be
      added, besides ADA, which is described on a separate page: BRIG (add
      <parameter>brig</parameter> to the list of enabled languages), a binary
      format for HSAIL (Heterogeneous System Architecture Intermediate
      Language), and JIT (add <parameter>jit</parameter> to the list of enabled
      languages), a library which can be linked into interpreters that
      want to generate machine code <quote>on the fly</quote> at run-time. They
      have not been tested by the BLFS developers.
    </para>

    <para>
      <option>--with-default-libstdcxx-abi=gcc4-compatible</option>: Use this
      switch if you are upgrading from a <application>GCC</application>
      version prior to 5.1.0, and you do not want to recompile all the
      libraries written in C++.
    </para>

    <para>
      <command>ulimit -s 32768</command>: This command prevents several
      tests from running out of stack space.
    </para>

    <para>
      <command>make -k check</command>: This command runs the test suite
      without stopping if any errors are encountered.
    </para>

    <para>
      <command>../contrib/test_summary</command>: This command will produce
      a summary of the test suite results. You can append <command>| grep
      -A7 Summ</command> to the command to produce an even more condensed
      version of the summary. You may also wish to redirect the output
      to a file for review and comparison later on.
    </para>

    <para>
      <command>mv -v /usr/lib/*gdb.py ...</command>: The installation
      stage puts some files used by <application>gdb</application> under the
      <filename class="directory">/usr/lib</filename> directory. This generates
      spurious error messages when performing <command>ldconfig</command>. This
      command moves the files to another location.
    </para>

    <para>
      <command>chown -v -R root:root /usr/lib/gcc/*linux-gnu/...</command>:
      If the package is built by a user other than root, the ownership of the
      installed <filename class="directory">include</filename> directory (and
      its content) will be incorrect. This command changes the ownership to the
      <systemitem class="username">root</systemitem> user and group.
    </para>

  </sect2>

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

    <para>
      Some program and library names and descriptions are not listed here,
      but can be found at
      <ulink url="&lfs-root;/chapter06/gcc.html#contents-gcc"/> as they were
      initially installed during the building of LFS.
    </para>

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

      <seglistitem>
        <seg>
          gccgo, go, gofmt, and gfortran, hard-linked to architecture specific
          names
        </seg>
        <seg>
          libgfortran.{so,a},
          libgo.{so,a}, libgobegin.a, libgolibbegin.a,
          libobjc.{so,a}, and numerous other run-time libraries and executables
        </seg>
        <seg>
          /usr/lib/go
        </seg>
      </seglistitem>
    </segmentedlist>

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

      <varlistentry id="gccgo">
        <term><command>gccgo</command></term>
        <listitem>
          <para>
            is a GCC-based compiler for the <application>Go</application>
            language.
          </para>
          <indexterm zone="gcc gccgo">
            <primary sortas="b-gccgo">gccgo</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="go">
        <term><command>go</command></term>
        <listitem>
          <para>
            is a tool for managing <application>Go</application> source code.
          </para>
          <indexterm zone="gcc go">
            <primary sortas="b-go">go</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="gofmt">
        <term><command>gofmt</command></term>
        <listitem>
          <para>
            is a tool for formatting <application>Go</application> source code.
          </para>
          <indexterm zone="gcc gofmt">
            <primary sortas="b-gofmt">gofmt</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="gfortran">
        <term><command>gfortran</command></term>
        <listitem>
          <para>
            is a GCC-based compiler for the <application>Fortran</application>
            language.
          </para>
          <indexterm zone="gcc gfortran">
            <primary sortas="b-gfortran">gfortran</primary>
          </indexterm>
        </listitem>
      </varlistentry>

    </variablelist>

  </sect2>

</sect1>