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81fd230419
git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@4648 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689
137 lines
5.1 KiB
XML
137 lines
5.1 KiB
XML
<?xml version="1.0" encoding="ISO-8859-1"?>
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<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
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<!ENTITY % general-entities SYSTEM "../general.ent">
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%general-entities;
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]>
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<sect1 id="ch-tools-gcc-pass1" role="wrap">
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<title>GCC-&gcc-version; - Pass 1</title>
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<?dbhtml filename="gcc-pass1.html"?>
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<indexterm zone="ch-tools-gcc-pass1">
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<primary sortas="a-GCC">GCC</primary>
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<secondary>tools, pass 1</secondary></indexterm>
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<sect2 role="package"><title/>
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<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="../chapter06/gcc.xml" xpointer="xpointer(/sect1/sect2[1]/para[1])"/>
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<segmentedlist>
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<segtitle>&buildtime;</segtitle>
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<segtitle>&diskspace;</segtitle>
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<seglistitem><seg>4.4 SBU</seg><seg>300 MB</seg></seglistitem>
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</segmentedlist>
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<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="../chapter06/gcc.xml" xpointer="xpointer(/sect1/sect2[1]/segmentedlist[2])"/>
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</sect2>
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<sect2 role="installation">
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<title>Installation of GCC</title>
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<para>Unpack only the gcc-core tarball because neither the C++
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compiler nor the test suite will be needed here.</para>
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<para>This package is known to have issues when its default
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optimization flags (including the <parameter>-march</parameter> and
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<parameter>-mcpu</parameter> options) are changed. If any environment
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variables that override default optimizations have been defined, such
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as <envar>CFLAGS</envar> and <envar>CXXFLAGS</envar>,
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unset them when building GCC.</para>
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<para>The GCC documentation recommends building GCC outside of the
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source directory in a dedicated build directory:</para>
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<screen><userinput>mkdir ../gcc-build
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cd ../gcc-build</userinput></screen>
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<para>Prepare GCC for compilation:</para>
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<screen><userinput>../gcc-&gcc-version;/configure --prefix=/tools \
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--libexecdir=/tools/lib --with-local-prefix=/tools \
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--disable-nls --enable-shared --enable-languages=c</userinput></screen>
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<para>The meaning of the configure options:</para>
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<variablelist>
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<varlistentry>
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<term><parameter>--with-local-prefix=/tools</parameter></term>
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<listitem><para>The purpose of this switch is to remove <filename class="directory">/usr/local/include</filename>
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from <command>gcc</command>'s include search path. This is not absolutely
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essential, however, it helps to minimize the influence of the host
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system.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>--enable-shared</parameter></term>
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<listitem><para>This switch may seem counter-intuitive at first.
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However, this switch allows the building of
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<filename class="libraryfile">libgcc_s.so.1</filename> and
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<filename class="libraryfile">libgcc_eh.a</filename>, and having
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<filename class="libraryfile">libgcc_eh.a</filename> available ensures that the configure
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script for Glibc (the next package we compile) produces the proper
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results. Note that the GCC binaries will still be linked statically
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because this is controlled by the <parameter>-static</parameter> value of
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the <envar>BOOT_LDFLAGS</envar> variable in the next
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step.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>--enable-languages=c</parameter></term>
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<listitem><para>This option ensures that only the C compiler is built.
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This option is only needed when you have downloaded and unpacked the
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full GCC tarball, as opposed to just the gcc-core
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tarball.</para></listitem>
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</varlistentry>
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</variablelist>
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<para>Continue with compiling the package:</para>
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<screen><userinput>make BOOT_LDFLAGS="-static" bootstrap</userinput></screen>
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<para>The meaning of the make parameters:</para>
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<variablelist>
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<varlistentry>
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<term><parameter>BOOT_LDFLAGS="-static"</parameter></term>
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<listitem><para>This tells GCC to link its programs statically.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>bootstrap</parameter></term>
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<listitem><para>This target does not just compile GCC, but compiles it
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several times. It uses the programs compiled in a first round to
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compile itself a second time, and then again a third time. It then
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compares these second and third compiles to make sure it can reproduce
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itself flawlessly. This also implies that it was compiled
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correctly.</para></listitem>
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</varlistentry>
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</variablelist>
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<para>Compilation is now complete. At this point, the test suite would
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normally be run, but, as mentioned before, the test suite framework is
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not in place yet. The benefits of running the tests at this point
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are minimal since the programs from this first pass will soon be
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replaced.</para>
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<para>Install the package:</para>
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<screen><userinput>make install</userinput></screen>
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<para>As a finishing touch, create a symlink. Many programs and
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scripts run <command>cc</command> instead of <command>gcc</command>, which is used to keep programs generic
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and therefore usable on all kinds of UNIX systems where the GNU C compiler
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is not always installed. Running <command>cc</command> leaves the system administrator
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free to decide which C compiler to install.</para>
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<screen><userinput>ln -s gcc /tools/bin/cc</userinput></screen>
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</sect2>
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<sect2 role="content"><title/>
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<para>Details on this package are located in <xref
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linkend="contents-gcc" role="."/></para>
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</sect2>
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</sect1>
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