1 | <?xml version="1.0" encoding="ISO-8859-1"?> |
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2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
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3 | "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [ |
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4 | <!ENTITY % general-entities SYSTEM "../../general.ent"> |
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5 | %general-entities; |
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6 | ]> |
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7 | |
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8 | <sect1 id="ch-system-adjusting"> |
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9 | <?dbhtml filename="adjusting.html"?> |
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10 | |
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11 | <title>Adjusting the Toolchain</title> |
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12 | |
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13 | <para os="a">Now we adjust GCC's specs so that they point to the new |
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14 | dynamic linker. A <command>perl</command> command accomplishes this:</para> |
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15 | |
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16 | <screen os="c"><userinput>gcc -dumpspecs | \ |
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17 | perl -p -e 's@/tools/lib/ld@/lib/ld@g;' \ |
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18 | -e 's@\*startfile_prefix_spec:\n@$_/usr/lib/ @g;' > \ |
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19 | $(dirname $(gcc --print-libgcc-file-name))/specs</userinput></screen> |
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20 | |
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21 | <para os="d">The <command>perl</command> command above makes 2 |
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22 | modifications to GCC's specs: it removes <quote>/tools</quote> from the |
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23 | pathname to the dynamic linker, and adds <quote>/usr/lib/</quote> to the |
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24 | startfile_prefix_spec. It is a good idea to visually inspect the |
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25 | <filename>specs</filename> file, and compare with the output of |
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26 | <command>gcc -dumpspecs</command>, to verify that |
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27 | the intended changes were actually made.</para> |
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28 | |
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29 | <caution> |
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30 | |
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31 | <para os="f">It is imperative at this point to stop and ensure that |
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32 | the basic functions (compiling and linking) of the adjusted toolchain |
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33 | are working as expected. To do this, perform a sanity |
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34 | check:</para> |
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35 | |
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36 | <screen os="g"><userinput>echo 'main(){}' > dummy.c |
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37 | gcc dummy.c |
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38 | readelf -l a.out | grep ': /lib'</userinput></screen> |
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39 | |
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40 | <para os="h">If everything is working correctly, there should be no errors, |
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41 | and the output of the last command will be:</para> |
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42 | |
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43 | <screen os="i"><computeroutput>[Requesting program interpreter: /lib/ld-linux.so.2]</computeroutput></screen> |
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44 | |
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45 | <para os="j">Note that <filename class="directory">/lib</filename> is now |
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46 | the prefix of our dynamic linker.</para> |
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47 | |
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48 | <para os="k">If the output does not appear as shown above or is not received |
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49 | at all, then something is seriously wrong. Investigate and retrace the |
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50 | steps to find out where the problem is and correct it. The most likely |
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51 | reason is that something went wrong with the specs file amendment |
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52 | above. Any issues will need to be resolved before continuing on with |
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53 | the process.</para> |
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54 | |
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55 | <para os="l">Once everything is working correctly, clean up the test |
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56 | files:</para> |
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57 | |
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58 | <screen os="m"><userinput>rm -v dummy.c a.out</userinput></screen> |
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59 | |
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60 | </caution> |
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61 | |
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62 | </sect1> |
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