1 | <?xml version="1.0" encoding="ISO-8859-1"?>
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2 | <!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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3 | <!ENTITY % general-entities SYSTEM "../general.ent">
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4 | %general-entities;
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5 | ]>
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6 | <sect1 id="ch-tools-adjusting">
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7 | <title>Adjusting the Toolchain</title>
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8 | <?dbhtml filename="adjusting.html"?>
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9 |
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10 | <para>Now that the temporary C libraries have been installed, all
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11 | tools compiled in the rest of this chapter should be linked against
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12 | these libraries. In order to accomplish this, the linker and the
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13 | compiler's specs file need to be adjusted.</para>
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14 |
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15 | <para>The linker, adjusted at the end of the first pass of Binutils,
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16 | is installed by running the following command from within the
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17 | <filename class="directory">binutils-build</filename> directory:</para>
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18 |
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19 | <screen><userinput>make -C ld install</userinput></screen>
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20 |
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21 | <para>From this point onwards, everything will link only
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22 | against the libraries in <filename class="directory">/tools/lib</filename>.</para>
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23 |
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24 | <note><para>If the earlier warning to retain the Binutils source and
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25 | build directories from the first pass was missed, ignore the above
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26 | command. This results in a small chance that the subsequent testing
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27 | programs will link against libraries on the host. This is not ideal,
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28 | but it is not a major problem. The situation is corrected when the
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29 | second pass of Binutils is installed later.</para></note>
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30 |
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31 | <para>Now that the adjusted linker is installed, the Binutils build and source
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32 | directories should be removed.</para>
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33 |
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34 | <para>The next task is to amend the GCC specs file so that it points
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35 | to the new dynamic linker. A simple sed script will accomplish this:</para>
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36 |
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37 | <!-- Ampersands are needed to allow copy and paste -->
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38 |
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39 | <screen><userinput>SPECFILE=`gcc --print-file specs` &&
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40 | sed 's@ /lib/ld-linux.so.2@ /tools/lib/ld-linux.so.2@g' \
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41 | $SPECFILE > tempspecfile &&
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42 | mv -f tempspecfile $SPECFILE &&
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43 | unset SPECFILE</userinput></screen>
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44 |
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45 | <para><phrase condition="html">It is recommended that the above
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46 | command be copy-and-pasted in order to ensure accuracy.</phrase>
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47 | Alternatively, the specs file can be edited by hand. This is done by
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48 | replacing every occurrence of <quote>/lib/ld-linux.so.2</quote> with
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49 | <quote>/tools/lib/ld-linux.so.2</quote></para>
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50 |
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51 | <para>Be sure to visually inspect the specs file in order to verify the
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52 | intended changes have been made.</para>
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53 |
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54 | <important><para>If working on a platform where the name of the
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55 | dynamic linker is something other than
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56 | <filename class="libraryfile">ld-linux.so.2</filename>, replace
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57 | <quote>ld-linux.so.2</quote> with the name of the platform's
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58 | dynamic linker in the above commands. Refer back to <xref
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59 | linkend="ch-tools-toolchaintechnotes" role=","/> if
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60 | necessary.</para></important>
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61 |
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62 | <para>There is a possibility that some include files from the host
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63 | system have found their way into GCC's private include dir. This can
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64 | happen as a result of GCC's <quote>fixincludes</quote> process, which runs as part
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65 | of the GCC build. This is explained in more detail later in this
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66 | chapter. Run the following command to eliminate this
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67 | possibility:</para>
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68 |
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69 | <screen><userinput>rm -f /tools/lib/gcc/*/*/include/{pthread.h,bits/sigthread.h}</userinput></screen>
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70 |
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71 | <beginpage/>
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72 |
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73 | <caution><para>At this point, it is imperative to stop and ensure that
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74 | the basic functions (compiling and linking) of the new toolchain are
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75 | working as expected. To perform a sanity check, run the following
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76 | commands:</para>
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77 |
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78 | <screen><userinput>echo 'main(){}' > dummy.c
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79 | cc dummy.c
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80 | readelf -l a.out | grep ': /tools'</userinput></screen>
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81 |
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82 | <para>If everything is working correctly, there should be no errors,
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83 | and the output of the last command will be of the form:</para>
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84 |
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85 | <screen><computeroutput>[Requesting program interpreter:
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86 | /tools/lib/ld-linux.so.2]</computeroutput></screen>
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87 |
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88 | <para>Note that <filename class="directory">/tools/lib</filename>
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89 | appears as the prefix of the dynamic linker.</para>
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90 |
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91 | <para>If the output is not shown as above or there was no output at
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92 | all, then something is wrong. Investigate and retrace the steps to
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93 | find out where the problem is and correct it. This issue must be
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94 | resolved before continuing on. First, perform the sanity check again,
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95 | using <command>gcc</command> instead of <command>cc</command>. If this
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96 | works, then the <filename class="symlink">/tools/bin/cc</filename> symlink is missing.
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97 | Revisit <xref linkend="ch-tools-gcc-pass1" role=","/> and install the symlink.
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98 | Next, ensure that the <envar>PATH</envar> is correct. This can be checked by running
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99 | <command>echo $PATH</command> and verifying that <filename
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100 | class="directory">/tools/bin</filename> is at the head of the list. If
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101 | the <envar>PATH</envar> is wrong it could mean that you are not logged in as user
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102 | <emphasis>lfs</emphasis> or that something went wrong back in <xref
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103 | linkend="ch-tools-settingenviron" role="."/> Another option is that something
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104 | may have gone wrong with the specs file amendment above. In this case,
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105 | redo the specs file amendment<phrase condition="html">, being careful to copy-and-paste the
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106 | commands</phrase>.</para>
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107 |
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108 | <para>Once all is well, clean up the test files:</para>
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109 |
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110 | <screen><userinput>rm dummy.c a.out</userinput></screen>
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111 | </caution>
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112 |
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113 | </sect1>
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114 |
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