| 1 | <sect1 id="ch06-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 by default are compiled with debugging
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| 6 | symbols (gcc option -g).</para>
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| 7 |
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| 8 | <para>A program compiled with debugging symbols means a user can run a program
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| 9 | or library through a debugger and the debugger's output will be user
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| 10 | friendly. These debugging symbols also enlarge the program or library
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| 11 | significantly.</para>
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| 12 |
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| 13 | <para>Before you start wondering whether these debugging symbols really make a
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| 14 | big difference, here are some statistics. Use them to draw your own
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| 15 | conclusion.</para>
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| 16 |
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| 17 | <itemizedlist>
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| 18 |
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| 19 | <listitem><para>A dynamic Bash binary
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| 20 | with debugging symbols: 1.2 MB</para></listitem>
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| 21 |
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| 22 | <listitem><para>A dynamic Bash binary
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| 23 | without debugging symbols: 478 KB</para></listitem>
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| 24 |
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| 25 | <listitem><para>/lib and /usr/lib (glibc
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| 26 | and gcc files) with debugging symbols: 87 MB</para></listitem>
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| 27 |
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| 28 | <listitem><para>/lib and /usr/lib (glibc
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| 29 | and gcc files) without debugging symbols: 16 MB</para></listitem>
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| 30 |
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| 31 | </itemizedlist>
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| 32 |
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| 33 | <para>Sizes vary depending on which compiler was used and which C library
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| 34 | version was used to link dynamic programs against, but results will be
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| 35 | similar if you compare programs with and without debugging symbols.</para>
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| 36 |
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| 37 | <para>To remove debugging symbols from a binary (must be an a.out or ELF
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| 38 | binary) run <userinput>strip --strip-debug filename</userinput>. Wildcards
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| 39 | can be used to strip debugging symbols from multiple files (use something
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| 40 | like <userinput>strip --strip-debug $LFS/usr/bin/*</userinput>).
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| 41 | Most people will probably never use a debugger on software, so by
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| 42 | removing those symbols a lot of disk space can be regained.</para>
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| 43 |
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| 44 | <para>For your convenience, chapter 9 includes one simple command to strip
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| 45 | all debugging symbols from all programs and libraries on your
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| 46 | system. If you are short on diskspace you can start with stripping
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| 47 | all the files under <filename class="directory">$LFS/static</filename></para>
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| 48 |
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| 49 | <para>You might find additional information in the optimization hint which can
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| 50 | be found at <ulink url="&hints-root;optimization.txt"/>.</para>
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| 51 |
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| 52 | </sect1>
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| 53 |
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