1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<!-- Copyright (C) 1988-2021 Free Software Foundation, Inc. 4 5Permission is granted to copy, distribute and/or modify this document 6under the terms of the GNU Free Documentation License, Version 1.3 or 7any later version published by the Free Software Foundation; with the 8Invariant Sections being "Free Software" and "Free Software Needs 9Free Documentation", with the Front-Cover Texts being "A GNU Manual," 10and with the Back-Cover Texts as in (a) below. 11 12(a) The FSF's Back-Cover Text is: "You are free to copy and modify 13this GNU Manual. Buying copies from GNU Press supports the FSF in 14developing GNU and promoting software freedom." --> 15<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ --> 16<head> 17<title>Debugging with GDB: Custom Debug Info</title> 18 19<meta name="description" content="Debugging with GDB: Custom Debug Info"> 20<meta name="keywords" content="Debugging with GDB: Custom Debug Info"> 21<meta name="resource-type" content="document"> 22<meta name="distribution" content="global"> 23<meta name="Generator" content="makeinfo"> 24<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 25<link href="index.html#Top" rel="start" title="Top"> 26<link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> 27<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> 28<link href="JIT-Interface.html#JIT-Interface" rel="up" title="JIT Interface"> 29<link href="Using-JIT-Debug-Info-Readers.html#Using-JIT-Debug-Info-Readers" rel="next" title="Using JIT Debug Info Readers"> 30<link href="Unregistering-Code.html#Unregistering-Code" rel="previous" title="Unregistering Code"> 31<style type="text/css"> 32<!-- 33a.summary-letter {text-decoration: none} 34blockquote.smallquotation {font-size: smaller} 35div.display {margin-left: 3.2em} 36div.example {margin-left: 3.2em} 37div.indentedblock {margin-left: 3.2em} 38div.lisp {margin-left: 3.2em} 39div.smalldisplay {margin-left: 3.2em} 40div.smallexample {margin-left: 3.2em} 41div.smallindentedblock {margin-left: 3.2em; font-size: smaller} 42div.smalllisp {margin-left: 3.2em} 43kbd {font-style:oblique} 44pre.display {font-family: inherit} 45pre.format {font-family: inherit} 46pre.menu-comment {font-family: serif} 47pre.menu-preformatted {font-family: serif} 48pre.smalldisplay {font-family: inherit; font-size: smaller} 49pre.smallexample {font-size: smaller} 50pre.smallformat {font-family: inherit; font-size: smaller} 51pre.smalllisp {font-size: smaller} 52span.nocodebreak {white-space:nowrap} 53span.nolinebreak {white-space:nowrap} 54span.roman {font-family:serif; font-weight:normal} 55span.sansserif {font-family:sans-serif; font-weight:normal} 56ul.no-bullet {list-style: none} 57--> 58</style> 59 60 61</head> 62 63<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> 64<a name="Custom-Debug-Info"></a> 65<div class="header"> 66<p> 67Previous: <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> [<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> 68</div> 69<hr> 70<a name="Custom-Debug-Info-1"></a> 71<h3 class="section">29.4 Custom Debug Info</h3> 72<a name="index-custom-JIT-debug-info"></a> 73<a name="index-JIT-debug-info-reader"></a> 74 75<p>Generating debug information in platform-native file formats (like ELF 76or COFF) may be an overkill for JIT compilers; especially if all the 77debug info is used for is displaying a meaningful backtrace. The 78issue can be resolved by having the JIT writers decide on a debug info 79format and also provide a reader that parses the debug info generated 80by the JIT compiler. This section gives a brief overview on writing 81such a parser. More specific details can be found in the source file 82<samp>gdb/jit-reader.in</samp>, which is also installed as a header at 83<samp><var>includedir</var>/gdb/jit-reader.h</samp> for easy inclusion. 84</p> 85<p>The reader is implemented as a shared object (so this functionality is 86not available on platforms which don’t allow loading shared objects at 87runtime). Two <small>GDB</small> commands, <code>jit-reader-load</code> and 88<code>jit-reader-unload</code> are provided, to be used to load and unload 89the readers from a preconfigured directory. Once loaded, the shared 90object is used the parse the debug information emitted by the JIT 91compiler. 92</p> 93<table class="menu" border="0" cellspacing="0"> 94<tr><td align="left" valign="top">• <a href="Using-JIT-Debug-Info-Readers.html#Using-JIT-Debug-Info-Readers" accesskey="1">Using JIT Debug Info Readers</a>:</td><td> </td><td align="left" valign="top">How to use supplied readers correctly 95</td></tr> 96<tr><td align="left" valign="top">• <a href="Writing-JIT-Debug-Info-Readers.html#Writing-JIT-Debug-Info-Readers" accesskey="2">Writing JIT Debug Info Readers</a>:</td><td> </td><td align="left" valign="top">Creating a debug-info reader 97</td></tr> 98</table> 99 100 101 102 103</body> 104</html> 105