lfs-book/chapter06/gcc.xml

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<sect1 id="ch-system-gcc" role="wrap">
  <?dbhtml filename="gcc.html"?>

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

  <indexterm zone="ch-system-gcc">
    <primary sortas="a-GCC">GCC</primary>
  </indexterm>

  <sect2 role="package">
    <title/>

    <para>The GCC package contains the GNU compiler collection, which includes
    the C and C++ compilers.</para>

    <segmentedlist>
      <segtitle>&buildtime;</segtitle>
      <segtitle>&diskspace;</segtitle>

      <seglistitem>
        <seg>11.7 SBU</seg>
        <seg>451 MB</seg>
      </seglistitem>
    </segmentedlist>

    <segmentedlist>
      <segtitle>&dependencies;</segtitle>

      <seglistitem>
        <seg>Bash, Binutils, Coreutils, DejaGNU, Diffutils, Findutils, Expect,
        Gawk, Gettext, Glibc, Grep, Make, Patch, Perl, Sed, Tcl, and Texinfo</seg>
      </seglistitem>
    </segmentedlist>

  </sect2>

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

    <para>Apply a <command>sed</command> substitution that will suppress the
    installation of <filename class="libraryfile">libiberty.a</filename>. The
    version of <filename class="libraryfile">libiberty.a</filename> provided by
    Binutils will be used instead:</para>

<screen><userinput>sed -i 's/install_to_$(INSTALL_DEST) //' libiberty/Makefile.in</userinput></screen>

    <para>The bootstrap build performed in <xref linkend="ch-tools-gcc-pass1"/>
    built GCC with the <option>-fomit-frame-pointer</option> compiler flag.
    Non-bootstrap builds omit this flag by default, so apply the following
    <command>sed</command> to use it in order to ensure consistent compiler
    builds.</para>

<screen><userinput>sed -i 's/^XCFLAGS =$/&amp; -fomit-frame-pointer/' gcc/Makefile.in</userinput></screen>

    <para>The <command>fixincludes</command> script is known to occasionally
    erroneously attempt to &quot;fix&quot; the system headers installed so far. As
    the headers installed by GCC-&gcc-version; and Glibc-&glibc-version; are known
    to not require fixing, issue the following command to prevent the
    <command>fixincludes</command> script from running:</para>

<screen><userinput>sed -i 's@\./fixinc\.sh@-c true@' gcc/Makefile.in</userinput></screen>

    <para>GCC provides a <command>gccbug</command> script which detects at
    compile time whether mktemp is present, and hardcodes the result in a test.
    This will cause the script to fall back to using less random names for
    temporary files.  We will be installing mktemp later, so the following sed
    will simulate its presence.</para>

<screen><userinput>sed -i 's/@have_mktemp_command@/yes/' gcc/gccbug.in</userinput></screen>

    <para>The GCC documentation recommends building GCC outside of the source
    directory in a dedicated build directory:</para>

<screen><userinput>mkdir -v ../gcc-build
cd ../gcc-build</userinput></screen>

    <para>Prepare GCC for compilation:</para>

<screen><userinput>../gcc-&gcc-version;/configure --prefix=/usr \
    --libexecdir=/usr/lib --enable-shared \
    --enable-threads=posix --enable-__cxa_atexit \
    --enable-clocale=gnu --enable-languages=c,c++</userinput></screen>

    <para>Compile the package:</para>

<screen><userinput>make</userinput></screen>

    <important>
      <para>In this section, the test suite for GCC is considered
      critical. Do not skip it under any circumstance.</para>
    </important>

    <para>Test the results, but do not stop at errors:</para>

<screen><userinput>make -k check</userinput></screen>

    <para>Some of the errors are known issues and were noted in the
    previous chapter. The test suite notes from <xref
    linkend="ch-tools-gcc-pass2" role=","/> are still relevant here. Be sure to
    refer back to them as necessary.</para>

    <para>Install the package:</para>

<screen><userinput>make install</userinput></screen>

    <para>Some packages expect the C preprocessor to be installed in the
    <filename class="directory">/lib</filename> directory.
    To support those packages, create this symlink:</para>

<screen><userinput>ln -sv ../usr/bin/cpp /lib</userinput></screen>

    <para>Many packages use the name <command>cc</command> to call the C
    compiler. To satisfy those packages, create a symlink:</para>

<screen><userinput>ln -sv gcc /usr/bin/cc</userinput></screen>

    <note>
      <para>At this point, it is strongly recommended to repeat the sanity
      check performed earlier in this chapter. Refer back to <xref
      linkend="ch-system-readjusting" role=","/> and repeat the check. If
      the results are in error, then the most likely reason is that the GCC
      Specs patch from <xref linkend="chapter-temporary-tools"/> was
      erroneously applied here.</para>
    </note>

  </sect2>

  <sect2 id="contents-gcc" role="content">
    <title>Contents of GCC</title>

    <segmentedlist>
      <segtitle>Installed programs</segtitle>
      <segtitle>Installed libraries</segtitle>

      <seglistitem>
        <seg>c++, cc (link to gcc), cpp, g++, gcc, gccbug, and gcov</seg>
        <seg>libgcc.a, libgcc_eh.a, libgcc_s.so, libstdc++.{a,so}, and
        libsupc++.a</seg>
      </seglistitem>
    </segmentedlist>

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

      <varlistentry id="cc">
        <term><command>cc</command></term>
        <listitem>
          <para>The C compiler</para>
          <indexterm zone="ch-system-gcc cc">
            <primary sortas="b-cc">cc</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="cpp">
        <term><command>cpp</command></term>
        <listitem>
          <para>The C preprocessor; it is used by the compiler to expand the
          #include, #define, and similar statements in the source files</para>
          <indexterm zone="ch-system-gcc cpp">
            <primary sortas="b-cpp">cpp</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="c">
        <term><command>c++</command></term>
        <listitem>
          <para>The C++ compiler</para>
          <indexterm zone="ch-system-gcc c">
            <primary sortas="b-c++">c++</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="g">
        <term><command>g++</command></term>
        <listitem>
          <para>The C++ compiler</para>
          <indexterm zone="ch-system-gcc g">
            <primary sortas="b-g++">g++</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="gcc">
        <term><command>gcc</command></term>
        <listitem>
          <para>The C compiler</para>
          <indexterm zone="ch-system-gcc gcc">
            <primary sortas="b-gcc">gcc</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="gccbug">
        <term><command>gccbug</command></term>
        <listitem>
          <para>A shell script used to help create useful bug reports</para>
          <indexterm zone="ch-system-gcc gccbug">
            <primary sortas="b-gccbug">gccbug</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="gcov">
        <term><command>gcov</command></term>
        <listitem>
          <para>A coverage testing tool; it is used to analyze programs to
          determine where optimizations will have the most effect</para>
          <indexterm zone="ch-system-gcc gcov">
            <primary sortas="b-gcov">gcov</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="libgcc">
        <term><filename class="libraryfile">libgcc</filename></term>
        <listitem>
          <para>Contains run-time support for <command>gcc</command></para>
          <indexterm zone="ch-system-gcc libgcc">
            <primary sortas="c-libgcc*">libgcc*</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="libstdc">
        <term><filename class="libraryfile">libstdc++</filename></term>
        <listitem>
          <para>The standard C++ library</para>
          <indexterm zone="ch-system-gcc libstdc">
            <primary sortas="c-libstdc++">libstdc++</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="libsupc">
        <term><filename class="libraryfile">libsupc++</filename></term>
        <listitem>
          <para>Provides supporting routines for the C++ programming
          language</para>
          <indexterm zone="ch-system-gcc libsupc">
            <primary sortas="c-libsupc++">libsupc++</primary>
          </indexterm>
        </listitem>
      </varlistentry>

    </variablelist>

  </sect2>

</sect1>