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Previous: <a href="Unregistering-Code.html#Unregistering-Code" accesskey="p" rel="previous">Unregistering Code</a>, Up: <a href="JIT-Interface.html#JIT-Interface" accesskey="u" rel="up">JIT Interface</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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<a name="Custom-Debug-Info-1"></a>
<h3 class="section">29.4 Custom Debug Info</h3>
<a name="index-custom-JIT-debug-info"></a>
<a name="index-JIT-debug-info-reader"></a>

<p>Generating debug information in platform-native file formats (like ELF
or COFF) may be an overkill for JIT compilers; especially if all the
debug info is used for is displaying a meaningful backtrace.  The
issue can be resolved by having the JIT writers decide on a debug info
format and also provide a reader that parses the debug info generated
by the JIT compiler.  This section gives a brief overview on writing
such a parser.  More specific details can be found in the source file
<samp>gdb/jit-reader.in</samp>, which is also installed as a header at
<samp><var>includedir</var>/gdb/jit-reader.h</samp> for easy inclusion.
</p>
<p>The reader is implemented as a shared object (so this functionality is
not available on platforms which don&rsquo;t allow loading shared objects at
runtime).  Two <small>GDB</small> commands, <code>jit-reader-load</code> and
<code>jit-reader-unload</code> are provided, to be used to load and unload
the readers from a preconfigured directory.  Once loaded, the shared
object is used the parse the debug information emitted by the JIT
compiler.
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">&bull; <a href="Using-JIT-Debug-Info-Readers.html#Using-JIT-Debug-Info-Readers" accesskey="1">Using JIT Debug Info Readers</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">How to use supplied readers correctly
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<tr><td align="left" valign="top">&bull; <a href="Writing-JIT-Debug-Info-Readers.html#Writing-JIT-Debug-Info-Readers" accesskey="2">Writing JIT Debug Info Readers</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Creating a debug-info reader
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