1 | <sect1 id="ch05-gcc-pass1">
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2 | <title>Installing GCC-&gcc-version; - Pass 1</title>
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3 | <?dbhtml filename="gcc-pass1.html" dir="chapter05"?>
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4 |
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5 | <screen>Estimated build time: &gcc-time-tools-pass1;
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6 | Estimated required disk space: &gcc-compsize-tools-pass1;</screen>
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7 |
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8 | &aa-gcc-shortdesc;
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9 | &aa-gcc-dep;
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10 |
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11 | <sect2><title> </title><para> </para></sect2>
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12 |
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13 | <sect2>
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14 | <title>Installation of GCC</title>
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15 |
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16 | <para>Unpack only the GCC-core tarball, as we won't be needing a C++ compiler
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17 | for the moment.</para>
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18 |
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19 | <note><para>Even though GCC is an important toolchain package, we are not
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20 | going to run the test suite at this early stage. First, the test suite framework
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21 | is not yet in place and second, the programs from this first pass will soon be
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22 | overwritten by those installed in the second pass.</para></note>
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23 |
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24 | <para>This package is known to behave badly when you have changed its
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25 | default optimization flags (including the -march and -mcpu options).
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26 | Therefore, if you have defined any environment variables that override
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27 | default optimizations, such as CFLAGS and CXXFLAGS, we recommend unsetting
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28 | or modifying them when building GCC.</para>
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29 |
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30 | <para>The GCC documentation recommends building GCC outside of the source
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31 | directory in a dedicated build directory:</para>
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32 |
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33 | <screen><userinput>mkdir ../gcc-build
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34 | cd ../gcc-build</userinput></screen>
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35 |
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36 | <para>Prepare GCC for compilation:</para>
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37 |
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38 | <screen><userinput>../gcc-&gcc-version;/configure --prefix=/tools \
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39 | --with-local-prefix=/tools \
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40 | --disable-nls --enable-shared \
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41 | --enable-languages=c</userinput></screen>
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42 |
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43 | <para>The meaning of the configure options:</para>
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44 |
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45 | <itemizedlist>
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46 | <listitem><para><userinput>--with-local-prefix=/tools</userinput>: The
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47 | purpose of this switch is to remove <filename>/usr/local/include</filename>
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48 | from <userinput>gcc</userinput>'s include search path. This is not absolutely
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49 | essential; however, we want to try to minimize the influence of the host
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50 | system, thus making this a sensible thing to do.</para></listitem>
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51 |
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52 | <listitem><para><userinput>--enable-shared</userinput>: This switch may
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53 | seem counter-intuitive at first. But using it allows the building of
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54 | <filename>libgcc_s.so.1</filename> and <filename>libgcc_eh.a</filename>, and
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55 | having <filename>libgcc_eh.a</filename> available ensures that the configure
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56 | script for Glibc (the next package we compile) produces the proper results.
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57 | Note that the <userinput>gcc</userinput> binaries will still be linked
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58 | statically, as this is controlled by the <userinput>-static</userinput>
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59 | value of BOOT_LDFLAGS further on.</para></listitem>
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60 |
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61 | <listitem><para><userinput>--enable-languages=c</userinput>: This option
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62 | ensures that only the C compiler is built. The option is only needed when you
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63 | have downloaded and unpacked the full GCC tarball.</para></listitem>
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64 | </itemizedlist>
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65 |
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66 | <para>Continue with compiling the package:</para>
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67 |
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68 | <screen><userinput>make BOOT_LDFLAGS="-static" bootstrap</userinput></screen>
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69 |
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70 | <para>The meaning of the make parameters:</para>
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71 |
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72 | <itemizedlist>
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73 | <listitem><para><userinput>BOOT_LDFLAGS="-static"</userinput>: This tells
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74 | GCC to link its programs statically.</para></listitem>
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75 |
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76 | <listitem><para><userinput>bootstrap</userinput>: This target doesn't just
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77 | compile GCC, but compiles it several times. It uses the programs compiled in
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78 | a first round to compile itself a second time, and then again a third time.
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79 | It then compares these second and third compiles to make sure it can
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80 | reproduce itself flawlessly, which most probably means that it was
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81 | compiled correctly.</para></listitem>
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82 | </itemizedlist>
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83 |
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84 | <para>And install the package:</para>
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85 |
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86 | <screen><userinput>make install</userinput></screen>
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87 |
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88 | <para>As a finishing touch we'll create the <filename
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89 | class="symlink">/tools/bin/cc</filename> symlink. Many programs and
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90 | scripts run <userinput>cc</userinput> instead of <userinput>gcc</userinput>,
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91 | a thing meant to keep programs generic and therefore usable on all kinds of
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92 | Unix systems. Not everybody has the GNU C compiler installed. Simply running
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93 | <userinput>cc</userinput> leaves the system administrator free to decide what
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94 | C compiler to install, as long as there's a symlink pointing to it:</para>
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95 |
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96 | <screen><userinput>ln -sf gcc /tools/bin/cc</userinput></screen>
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97 |
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98 | </sect2>
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99 |
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100 | </sect1>
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101 |
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