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git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@4664 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689
113 lines
5.0 KiB
XML
113 lines
5.0 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-adjusting">
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<title>Adjusting the Toolchain</title>
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<?dbhtml filename="adjusting.html"?>
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<para>Now that the temporary C libraries have been installed, all
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tools compiled in the rest of this chapter should be linked against
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these libraries. In order to accomplish this, the linker and the
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compiler's specs file need to be adjusted.</para>
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<para>The linker, adjusted at the end of the first pass of Binutils,
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is installed by running the following command from within the
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<filename class="directory">binutils-build</filename> directory:</para>
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<screen><userinput>make -C ld install</userinput></screen>
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<para>From this point onwards, everything will link only
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against the libraries in <filename class="directory">/tools/lib</filename>.</para>
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<note><para>If the earlier warning to retain the Binutils source and
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build directories from the first pass was missed, ignore the above
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command. This results in a small chance that the subsequent testing
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programs will link against libraries on the host. This is not ideal,
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but it is not a major problem. The situation is corrected when the
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second pass of Binutils is installed later.</para></note>
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<para>Now that the adjusted linker is installed, the Binutils build and source
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directories should be removed.</para>
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<para>The next task is to amend the GCC specs file so that it points
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to the new dynamic linker. A simple sed script will accomplish this:</para>
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<!-- Ampersands are needed to allow copy and paste -->
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<screen><userinput>SPECFILE=`gcc --print-file specs` &&
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sed 's@ /lib/ld-linux.so.2@ /tools/lib/ld-linux.so.2@g' \
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$SPECFILE > tempspecfile &&
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mv -f tempspecfile $SPECFILE &&
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unset SPECFILE</userinput></screen>
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<para>It is recommended that the above
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command be copy-and-pasted in order to ensure accuracy.
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Alternatively, the specs file can be edited by hand. This is done by
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replacing every occurrence of <quote>/lib/ld-linux.so.2</quote> with
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<quote>/tools/lib/ld-linux.so.2</quote></para>
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<para>Be sure to visually inspect the specs file in order to verify the
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intended changes have been made.</para>
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<important><para>If working on a platform where the name of the
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dynamic linker is something other than
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<filename class="libraryfile">ld-linux.so.2</filename>, replace
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<quote>ld-linux.so.2</quote> with the name of the platform's
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dynamic linker in the above commands. Refer back to <xref
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linkend="ch-tools-toolchaintechnotes" role=","/> if
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necessary.</para></important>
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<para>There is a possibility that some include files from the host
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system have found their way into GCC's private include dir. This can
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happen as a result of GCC's <quote>fixincludes</quote> process, which runs as part
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of the GCC build. This is explained in more detail later in this
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chapter. Run the following command to eliminate this
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possibility:</para>
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<screen><userinput>rm -f /tools/lib/gcc/*/*/include/{pthread.h,bits/sigthread.h}</userinput></screen>
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<caution><para>At this point, it is imperative to stop and ensure that
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the basic functions (compiling and linking) of the new toolchain are
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working as expected. To perform a sanity check, run the following
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commands:</para>
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<screen><userinput>echo 'main(){}' > dummy.c
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cc dummy.c
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readelf -l a.out | grep ': /tools'</userinput></screen>
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<para>If everything is working correctly, there should be no errors,
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and the output of the last command will be of the form:</para>
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<screen><computeroutput>[Requesting program interpreter:
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/tools/lib/ld-linux.so.2]</computeroutput></screen>
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<para>Note that <filename class="directory">/tools/lib</filename>
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appears as the prefix of the dynamic linker.</para>
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<para>If the output is not shown as above or there was no output at
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all, then something is wrong. Investigate and retrace the steps to
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find out where the problem is and correct it. This issue must be
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resolved before continuing on. First, perform the sanity check again,
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using <command>gcc</command> instead of <command>cc</command>. If this
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works, then the <filename class="symlink">/tools/bin/cc</filename> symlink is missing.
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Revisit <xref linkend="ch-tools-gcc-pass1" role=","/> and install the symlink.
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Next, ensure that the <envar>PATH</envar> is correct. This can be checked by running
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<command>echo $PATH</command> and verifying that <filename
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class="directory">/tools/bin</filename> is at the head of the list. If
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the <envar>PATH</envar> is wrong it could mean that you are not logged in as user
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<emphasis>lfs</emphasis> or that something went wrong back in <xref
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linkend="ch-tools-settingenviron" role="."/> Another option is that something
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may have gone wrong with the specs file amendment above. In this case,
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redo the specs file amendment, being careful to copy-and-paste the
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commands.</para>
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<para>Once all is well, clean up the test files:</para>
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<screen><userinput>rm dummy.c a.out</userinput></screen>
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</caution>
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</sect1>
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