[673b0d8] | 1 | <?xml version="1.0" encoding="ISO-8859-1"?>
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| 2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN" "http://www.oasis-open.org/docbook/xml/4.3/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-system-readjusting">
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| 7 | <title>Re-adjusting the toolchain</title>
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| 8 | <?dbhtml filename="readjusting.html"?>
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| 9 |
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[ef13657] | 10 | <para>Now that the new and final C libraries have been installed, it
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| 11 | is time to adjust the toolchain again. The toolchain will be adjusted
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| 12 | so that it will link any newly compiled program against these new
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| 13 | libraries. This is the same process used in the
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| 14 | <quote>Adjusting</quote> phase in the beginning of <xref
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| 15 | linkend="chapter-temporary-tools"/>, even though it looks to be
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| 16 | reversed -- in that chapter, the chain was guided from the host's
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| 17 | <filename class="directory">/{,usr/}lib</filename> directories to the
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| 18 | new <filename class="directory">/tools/lib</filename> directory. Now,
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| 19 | the chain will be guided from that same <filename
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| 20 | class="directory">/tools/lib</filename> directory to the LFS's
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| 21 | <filename class="directory">/{,usr/}lib</filename> directories.</para>
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| 22 |
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| 23 | <para>Start by adjusting the linker. The source and build directories
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| 24 | from the second pass over Binutils were retained for this purpose.
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| 25 | Install the adjusted linker by running the following command from
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| 26 | within the <filename class="directory">binutils-build</filename>
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| 27 | directory:</para>
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[673b0d8] | 28 |
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| 29 | <screen><userinput>make -C ld INSTALL=/tools/bin/install install</userinput></screen>
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| 30 |
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[ef13657] | 31 | <note><para>If the earlier warning to retain the Binutils source and
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| 32 | build directories from the second pass in <xref
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| 33 | linkend="chapter-temporary-tools"/> was missed, or if they were
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| 34 | accidentally deleted or are inaccessible, ignore the above command.
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| 35 | The result will be that the next package, Binutils, will link against
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| 36 | the C libraries in <filename class="directory">/tools</filename>
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| 37 | rather than in <filename class="directory">/{,usr/}lib</filename>.
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| 38 | This is not ideal, however, testing has shown that the resulting
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| 39 | Binutils program binaries should be identical.</para></note>
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| 40 |
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| 41 | <para>From now on, every compiled program will link only against the
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| 42 | libraries in <filename class="directory">/usr/lib</filename> and
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[8ad7980] | 43 | <filename class="directory">/lib</filename>. The extra
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[ef13657] | 44 | <parameter>INSTALL=/tools/bin/install</parameter> option is needed
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| 45 | because the <filename>Makefile</filename> file created during the
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| 46 | second pass still contains the reference to
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| 47 | <command>/usr/bin/install</command>, which has not been installed yet.
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| 48 | Some host distributions contain a <filename
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| 49 | class="symlink">ginstall</filename> symbolic link which takes
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| 50 | precedence in the <filename>Makefile</filename> file and can cause a
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| 51 | problem here. The above command takes care of this issue.</para>
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[673b0d8] | 52 |
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[ef13657] | 53 | <para>Remove the Binutils source and build directories now.</para>
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[673b0d8] | 54 |
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[ef13657] | 55 | <para>Next, amend the GCC specs file so that it points to the new
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| 56 | dynamic linker. A sed to accomplish this just like before:</para>
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[673b0d8] | 57 |
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| 58 | <!-- Ampersands are needed to allow cut and paste -->
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| 59 |
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[2ec4b60] | 60 | <screen><userinput>sed -i 's@ /tools/lib/ld-linux.so.2@ /lib/ld-linux.so.2@g' \
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| 61 | `gcc --print-file specs`</userinput></screen>
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[673b0d8] | 62 |
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[ef13657] | 63 | <para>Cutting and pasting the above is recommended. It is a good idea
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| 64 | to visually inspect the specs file to verify the intended change was
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| 65 | actually made.</para>
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[673b0d8] | 66 |
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[ef13657] | 67 | <important><para>If working on a platform where the name of the
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| 68 | dynamic linker is something other than
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| 69 | <filename>ld-linux.so.2</filename>, substitute
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| 70 | <filename>ld-linux.so.2</filename> with the name of the platform's
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| 71 | dynamic linker in the above commands. Refer back to <xref
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| 72 | linkend="ch-tools-toolchaintechnotes"/> if
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| 73 | necessary.</para></important>
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[673b0d8] | 74 |
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[ef13657] | 75 | <caution><para>It is imperative at this point to stop and ensure that
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| 76 | the basic functions (compiling and linking) of the adjusted toolchain
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| 77 | are working as expected. To do this, perform a simple sanity
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| 78 | check:</para>
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[673b0d8] | 79 |
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| 80 | <screen><userinput>echo 'main(){}' > dummy.c
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| 81 | cc dummy.c
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| 82 | readelf -l a.out | grep ': /lib'</userinput></screen>
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| 83 |
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[ef13657] | 84 | <para>If everything is working correctly, there should be no errors,
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| 85 | and the output of the last command will be (allowing for platform
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| 86 | specific differences in dynamic linker name):</para>
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[673b0d8] | 87 |
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[8ad7980] | 88 | <screen><computeroutput>[Requesting program interpreter: /lib/ld-linux.so.2]</computeroutput></screen>
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[673b0d8] | 89 |
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| 90 | <para>Note especially that <filename class="directory">/lib</filename> is now
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| 91 | the prefix of our dynamic linker.</para>
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| 92 |
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[ef13657] | 93 | <para>If the output does not appear as shown above or is not received
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| 94 | at all, then something is seriously wrong. Investigate and retrace the
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| 95 | steps to find out where the problem is and correct it. The most likely
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| 96 | reason is that something went wrong with the specs file amendment
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| 97 | above. Any issues will need to be resolved before continuing on with
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| 98 | the process.</para>
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[673b0d8] | 99 |
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[ef13657] | 100 | <para>Once everything is working correctly, clean up the test
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| 101 | files:</para>
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[673b0d8] | 102 |
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[ef13657] | 103 | <screen><userinput>rm dummy.c a.out</userinput></screen></caution>
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[673b0d8] | 104 |
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| 105 | </sect1>
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[ef13657] | 106 |
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