| 1 | <sect1 id="ch-system-aboutdebug">
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| 2 | <title>About debugging symbols</title>
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| 3 | <?dbhtml filename="aboutdebug.html" dir="chapter06"?>
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| 4 |
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| 5 | <para>Most programs and libraries are, by default, compiled with debugging
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| 6 | symbols included (with gcc option -g).</para>
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| 7 |
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| 8 | <para>When debugging a program or library that was compiled with debugging
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| 9 | information included, the debugger can give you not only memory addresses
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| 10 | but also the names of the routines and variables.</para>
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| 11 |
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| 12 | <para>But the inclusion of these debugging symbols enlarges a program or
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| 13 | library significantly. To get an idea of the amount of space these symbols
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| 14 | occupy, have a look at the following:</para>
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| 15 |
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| 16 | <itemizedlist>
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| 17 |
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| 18 | <listitem><para>a bash binary
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| 19 | with debugging symbols: 1200 KB</para></listitem>
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| 20 |
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| 21 | <listitem><para>a bash binary
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| 22 | without debugging symbols: 480 KB</para></listitem>
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| 23 |
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| 24 | <listitem><para>Glibc and GCC files (/lib and /usr/lib)
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| 25 | with debugging symbols: 87 MB</para></listitem>
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| 26 |
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| 27 | <listitem><para>Glibc and GCC files
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| 28 | without debugging symbols: 16 MB</para></listitem>
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| 29 |
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| 30 | </itemizedlist>
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| 31 |
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| 32 | <para>Sizes may vary a little, depending on which compiler was used and
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| 33 | which C library. But when comparing programs with and without debugging
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| 34 | symbols, the difference will generally be a factor between 2 and 5.</para>
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| 35 |
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| 36 | <para>As most people will probably never use a debugger on their system
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| 37 | software, a lot of disk space can be regained by removing these symbols .</para>
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| 38 |
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| 39 | <para>To remove debugging symbols from a binary (which must be an a.out
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| 40 | or ELF binary), run <command>strip --strip-debug filename</command>.
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| 41 | Wildcards can be used to treat multiple files (use something like
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| 42 | <userinput>strip --strip-debug $LFS/tools/bin/*</userinput>).</para>
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| 43 |
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| 44 | <para>For your convenience, <xref linkend="chapter-finalizing"/> includes one simple
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| 45 | command to strip all debugging symbols from all programs and libraries on your
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| 46 | system. Additional information on optimization can be found in the hint at
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| 47 | <ulink url="&hints-root;optimization.txt"/>.</para>
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| 48 |
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| 49 | </sect1>
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| 50 |
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