chapter05/gcc-pass1.xml

   1 <?xml version="1.0" encoding="ISO-8859-1"?>
   2 <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
   4   <!ENTITY % general-entities SYSTEM "../general.ent">
   5   %general-entities;
   6 ]>
   7
   8 <sect1 id="ch-tools-gcc-pass1" role="wrap" xreflabel="gcc-pass1">
   9   <?dbhtml filename="gcc-pass1.html"?>
  10
  11   <sect1info condition="script">
  12     <productname>gcc-pass1</productname>
  13     <productnumber>&gcc-version;</productnumber>
  14     <address>&gcc-url;</address>
  15   </sect1info>
  16
  17   <title>GCC-&gcc-version; - Pass 1</title>
  18
  19   <indexterm zone="ch-tools-gcc-pass1">
  20     <primary sortas="a-GCC">GCC</primary>
  21     <secondary>tools, pass 1</secondary>
  22   </indexterm>
  23
  24   <sect2 role="package">
  25     <title/>
  26
  27     <xi:include xmlns:xi="http://www.w3.org/2001/XInclude"
  28     href="../chapter06/gcc.xml"
  29     xpointer="xpointer(/sect1/sect2[1]/para[1])"/>
  30
  31     <segmentedlist>
  32       <segtitle>&buildtime;</segtitle>
  33       <segtitle>&diskspace;</segtitle>
  34
  35       <seglistitem>
  36         <seg>&gcc-ch5p1-sbu;</seg>
  37         <seg>&gcc-ch5p1-du;</seg>
  38       </seglistitem>
  39     </segmentedlist>
  40
  41   </sect2>
  42
  43   <sect2 role="installation">
  44     <title>Installation of Cross GCC</title>
  45
  46     <para>GCC now requires the GMP, MPFR and MPC packages. As these packages may
  47     not be included in your host distribution, they will be built with
  48     GCC.  Unpack each package into the GCC source directory and rename the
  49     resulting directories so the GCC build procedures will automatically
  50     use them:</para>
  51
  52     <note><para>There are frequent misunderstandings about this chapter.  The
  53     procedures are the same as every other chapter as explained earlier (<xref
  54     linkend='buildinstr'/>).  First extract the gcc tarball from the sources
  55     directory and then change to the directory created.  Only then should you
  56     proceed with the instructions below.</para></note>
  57
  58 <screen><userinput remap="pre">tar -xf ../mpfr-&mpfr-version;.tar.xz
  59 mv -v mpfr-&mpfr-version; mpfr
  60 tar -xf ../gmp-&gmp-version;.tar.xz
  61 mv -v gmp-&gmp-version; gmp
  62 tar -xf ../mpc-&mpc-version;.tar.gz
  63 mv -v mpc-&mpc-version; mpc</userinput></screen>
  64
  65     <para>The following command will change the location of GCC's default
  66     dynamic linker to use the one installed in <filename
  67     class="directory">/tools</filename>. It also removes <filename
  68     class="directory">/usr/include</filename> from GCC's include search path.
  69     Issue:</para>
  70
  71 <screen><userinput remap="pre">for file in gcc/config/{linux,i386/linux{,64}}.h
  72 do
  73   cp -uv $file{,.orig}
  74   sed -e 's@/lib\(64\)\?\(32\)\?/ld@/tools&amp;@g' \
  75       -e 's@/usr@/tools@g' $file.orig &gt; $file
  76   echo '
  77 #undef STANDARD_STARTFILE_PREFIX_1
  78 #undef STANDARD_STARTFILE_PREFIX_2
  79 #define STANDARD_STARTFILE_PREFIX_1 "/tools/lib/"
  80 #define STANDARD_STARTFILE_PREFIX_2 ""' &gt;&gt; $file
  81   touch $file.orig
  82 done</userinput></screen>
  83
  84     <para>In case the above seems hard to follow, let's break it down a bit.
  85     First we copy the files <filename>gcc/config/linux.h</filename>,
  86     <filename>gcc/config/i386/linux.h</filename>, and
  87     <filename>gcc/config/i368/linux64.h</filename> to a file of
  88     the same name but with an added suffix of <quote>.orig</quote>. Then the
  89     first sed expression prepends <quote>/tools</quote> to every instance of
  90     <quote>/lib/ld</quote>, <quote>/lib64/ld</quote> or
  91     <quote>/lib32/ld</quote>, while the second one replaces hard-coded
  92     instances of <quote>/usr</quote>. Next, we add our define statements which
  93     alter the default startfile prefix to the end of the file. Note that the
  94     trailing <quote>/</quote> in <quote>/tools/lib/</quote> is required.
  95     Finally, we use <command>touch</command> to update the timestamp on the
  96     copied files.  When used in conjunction with <command>cp -u</command>, this
  97     prevents unexpected changes to the original files in case the commands are
  98     inadvertently run twice.</para>
  99
 100     <para>Finally, on x86_64 hosts, set the default directory name for
 101     64-bit libraries to <quote>lib</quote>:</para>
 102
 103 <screen><userinput remap="pre">case $(uname -m) in
 104   x86_64)
 105     sed -e '/m64=/s/lib64/lib/' \
 106         -i.orig gcc/config/i386/t-linux64
 107  ;;
 108 esac</userinput></screen>
 109
 110 <!--
 111     <para>GCC doesn't detect stack protection correctly, which causes problems
 112     for the build of Glibc-&glibc-version;, so fix that by issuing the following
 113     command:</para>
 114
 115 <screen><userinput remap="pre">sed -i '/k prot/agcc_cv_libc_provides_ssp=yes' gcc/configure</userinput></screen>
 116 -->
 117
 118 <!--
 119     <para>Also fix a problem identified upstream:</para>
 120
 121 <screen><userinput remap="pre">sed -i 's/if \((code.*))\)/if (\1 \&amp;\&amp; \!DEBUG_INSN_P (insn))/' gcc/sched-deps.c</userinput></screen>
 122 -->
 123     <para>The GCC documentation recommends building GCC
 124     in a dedicated build directory:</para>
 125
 126 <screen><userinput remap="pre">mkdir -v build
 127 cd       build</userinput></screen>
 128
 129     <para>Prepare GCC for compilation:</para>
 130
 131 <screen><userinput remap="configure">../configure                                       \
 132     --target=$LFS_TGT                              \
 133     --prefix=/tools                                \
 134     --with-glibc-version=2.11                      \
 135     --with-sysroot=$LFS                            \
 136     --with-newlib                                  \
 137     --without-headers                              \
 138     --with-local-prefix=/tools                     \
 139     --with-native-system-header-dir=/tools/include \
 140     --disable-nls                                  \
 141     --disable-shared                               \
 142     --disable-multilib                             \
 143     --disable-decimal-float                        \
 144     --disable-threads                              \
 145     --disable-libatomic                            \
 146     --disable-libgomp                              \
 147     --disable-libquadmath                          \
 148     --disable-libssp                               \
 149     --disable-libvtv                               \
 150     --disable-libstdcxx                            \
 151     --enable-languages=c,c++</userinput></screen>
 152     <variablelist>
 153       <title>The meaning of the configure options:</title>
 154
 155       <varlistentry>
 156         <term><parameter>--with-glibc-version=2.11</parameter></term>
 157         <listitem>
 158           <para>This option ensures the package will be compatible with the host's
 159           version of glibc.  It is set to the minimum glibc requirement
 160           specified in the <xref linkend="ch-partitioning-hostreqs"/>.</para>
 161         </listitem>
 162       </varlistentry>
 163
 164       <varlistentry>
 165         <term><parameter>--with-newlib</parameter></term>
 166         <listitem>
 167           <para>Since a working C library is not yet available, this ensures
 168           that the inhibit_libc constant is defined when building libgcc. This prevents
 169           the compiling of any code that requires libc support.</para>
 170         </listitem>
 171       </varlistentry>
 172
 173       <varlistentry>
 174         <term><parameter>--without-headers</parameter></term>
 175         <listitem>
 176           <para>When creating a complete cross-compiler, GCC requires
 177           standard headers compatible with the target system. For our
 178           purposes these headers will not be needed. This switch prevents
 179           GCC from looking for them.</para>
 180         </listitem>
 181       </varlistentry>
 182
 183       <varlistentry>
 184         <term><parameter>--with-local-prefix=/tools</parameter></term>
 185         <listitem>
 186           <para>The local prefix is the location in the system that GCC will search
 187           for locally installed include files. The default is <filename>/usr/local</filename>.
 188           Setting this to <filename>/tools</filename> helps keep the host location of
 189           <filename>/usr/local</filename> out of this GCC's search path.</para>
 190         </listitem>
 191       </varlistentry>
 192
 193       <varlistentry>
 194         <term><parameter>--with-native-system-header-dir=/tools/include</parameter></term>
 195         <listitem>
 196           <para>By default, GCC searches <filename>/usr/include</filename> for
 197           system headers. In conjunction with the sysroot switch, this would
 198           normally translate to <filename>$LFS/usr/include</filename>. However
 199           the headers that will be installed in the next two sections will go
 200           to <filename>$LFS/tools/include</filename>. This switch ensures that
 201           gcc will find them correctly. In the second pass of GCC, this same
 202           switch will ensure that no headers from the host system are
 203           found.</para>
 204         </listitem>
 205       </varlistentry>
 206
 207       <varlistentry>
 208         <term><parameter>--disable-shared</parameter></term>
 209         <listitem>
 210           <para>This switch forces GCC to link its internal libraries
 211           statically. We do this to avoid possible issues with the host
 212           system.</para>
 213         </listitem>
 214       </varlistentry>
 215
 216       <varlistentry>
 217         <term><parameter>--disable-decimal-float, --disable-threads,
 218               --disable-libatomic, --disable-libgomp, <!--- -disable-libmpx,-->
 219         --disable-libquadmath, --disable-libssp, --disable-libvtv,
 220         --disable-libstdcxx</parameter></term>
 221         <listitem>
 222           <para>These switches disable support for the decimal floating point
 223           extension, threading, libatomic, libgomp, <!--libmpx, --> libquadmath, libssp,
 224           libvtv, and the C++ standard library respectively. These features
 225           will fail to compile when building a cross-compiler and are not
 226           necessary for the task of cross-compiling the temporary libc.</para>
 227         </listitem>
 228       </varlistentry>
 229
 230       <varlistentry>
 231         <term><parameter>--disable-multilib</parameter></term>
 232         <listitem>
 233           <para>On x86_64, LFS does not yet support a multilib configuration.
 234           This switch is harmless for x86.</para>
 235         </listitem>
 236       </varlistentry>
 237
 238       <varlistentry>
 239         <term><parameter>--enable-languages=c,c++</parameter></term>
 240         <listitem>
 241           <para>This option ensures that only the C and C++ compilers are built.
 242           These are the only languages needed now.</para>
 243         </listitem>
 244       </varlistentry>
 245
 246     </variablelist>
 247
 248     <para>Compile GCC by running:</para>
 249
 250 <screen><userinput remap="make">make</userinput></screen>
 251
 252     <para>Compilation is now complete. At this point, the test suite would
 253     normally be run, but, as mentioned before, the test suite framework is
 254     not in place yet. The benefits of running the tests at this point
 255     are minimal since the programs from this first pass will soon be
 256     replaced.</para>
 257
 258     <para>Install the package:</para>
 259
 260 <screen><userinput remap="install">make install</userinput></screen>
 261 <!--
 262     <para>Using <parameter>- -disable-shared</parameter> means that the
 263     <filename>libgcc_eh.a</filename> file isn't created and installed. The
 264     Glibc package depends on this library as it uses
 265     <parameter>-lgcc_eh</parameter> within its build system. This dependency
 266     can be satisfied by creating a symlink to <filename>libgcc.a</filename>,
 267     since that file will end up containing the objects normally contained in
 268     <filename>libgcc_eh.a</filename>:</para>
 269
 270 <screen><userinput remap="install">ln -sv libgcc.a `$LFS_TGT-gcc -print-libgcc-file-name | sed 's/libgcc/&amp;_eh/'`</userinput></screen>
 271 -->
 272   </sect2>
 273
 274   <sect2 role="content">
 275     <title/>
 276
 277     <para>Details on this package are located in
 278     <xref linkend="contents-gcc" role="."/></para>
 279
 280   </sect2>
 281
 282 </sect1>