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diff --git a/share/doc/gdb/Index-Files.html b/share/doc/gdb/Index-Files.html new file mode 100644 index 0000000..1fe44de --- /dev/null +++ b/share/doc/gdb/Index-Files.html @@ -0,0 +1,207 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 1988-2023 Free Software Foundation, Inc. + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.3 or +any later version published by the Free Software Foundation; with the +Invariant Sections being "Free Software" and "Free Software Needs +Free Documentation", with the Front-Cover Texts being "A GNU Manual," +and with the Back-Cover Texts as in (a) below. + +(a) The FSF's Back-Cover Text is: "You are free to copy and modify +this GNU Manual. Buying copies from GNU Press supports the FSF in +developing GNU and promoting software freedom." --> +<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>Debugging with GDB: Index Files</title> + +<meta name="description" content="Debugging with GDB: Index Files"> +<meta name="keywords" content="Debugging with GDB: Index Files"> +<meta name="resource-type" content="document"> +<meta name="distribution" content="global"> +<meta name="Generator" content="makeinfo"> +<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> +<link href="index.html#Top" rel="start" title="Top"> +<link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="GDB-Files.html#GDB-Files" rel="up" title="GDB Files"> +<link href="Symbol-Errors.html#Symbol-Errors" rel="next" title="Symbol Errors"> +<link href="MiniDebugInfo.html#MiniDebugInfo" rel="previous" title="MiniDebugInfo"> +<style type="text/css"> +<!-- +a.summary-letter {text-decoration: none} +blockquote.smallquotation {font-size: smaller} +div.display {margin-left: 3.2em} +div.example {margin-left: 3.2em} +div.indentedblock {margin-left: 3.2em} +div.lisp {margin-left: 3.2em} +div.smalldisplay {margin-left: 3.2em} +div.smallexample {margin-left: 3.2em} +div.smallindentedblock {margin-left: 3.2em; font-size: smaller} +div.smalllisp {margin-left: 3.2em} +kbd {font-style:oblique} +pre.display {font-family: inherit} +pre.format {font-family: inherit} +pre.menu-comment {font-family: serif} +pre.menu-preformatted {font-family: serif} +pre.smalldisplay {font-family: inherit; font-size: smaller} +pre.smallexample {font-size: smaller} +pre.smallformat {font-family: inherit; font-size: smaller} +pre.smalllisp {font-size: smaller} +span.nocodebreak {white-space:nowrap} +span.nolinebreak {white-space:nowrap} +span.roman {font-family:serif; font-weight:normal} +span.sansserif {font-family:sans-serif; font-weight:normal} +ul.no-bullet {list-style: none} +--> +</style> + + +</head> + +<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> +<a name="Index-Files"></a> +<div class="header"> +<p> +Next: <a href="Symbol-Errors.html#Symbol-Errors" accesskey="n" rel="next">Symbol Errors</a>, Previous: <a href="MiniDebugInfo.html#MiniDebugInfo" accesskey="p" rel="previous">MiniDebugInfo</a>, Up: <a href="GDB-Files.html#GDB-Files" accesskey="u" rel="up">GDB Files</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> +</div> +<hr> +<a name="Index-Files-Speed-Up-GDB"></a> +<h3 class="section">18.5 Index Files Speed Up <small>GDB</small></h3> +<a name="index-index-files"></a> +<a name="index-_002egdb_005findex-section"></a> + +<p>When <small>GDB</small> finds a symbol file, it scans the symbols in the +file in order to construct an internal symbol table. This lets most +<small>GDB</small> operations work quickly—at the cost of a delay early +on. For large programs, this delay can be quite lengthy, so +<small>GDB</small> provides a way to build an index, which speeds up +startup. +</p> +<p>For convenience, <small>GDB</small> comes with a program, +<code>gdb-add-index</code>, which can be used to add the index to a +symbol file. It takes the symbol file as its only argument: +</p> +<div class="smallexample"> +<pre class="smallexample">$ gdb-add-index symfile +</pre></div> + +<p>See <a href="gdb_002dadd_002dindex-man.html#gdb_002dadd_002dindex">gdb-add-index</a>. +</p> +<p>It is also possible to do the work manually. Here is what +<code>gdb-add-index</code> does behind the curtains. +</p> +<p>The index is stored as a section in the symbol file. <small>GDB</small> can +write the index to a file, then you can put it into the symbol file +using <code>objcopy</code>. +</p> +<p>To create an index file, use the <code>save gdb-index</code> command: +</p> +<dl compact="compact"> +<dt><code>save gdb-index [-dwarf-5] <var>directory</var></code></dt> +<dd><a name="index-save-gdb_002dindex"></a> +<p>Create index files for all symbol files currently known by +<small>GDB</small>. For each known <var>symbol-file</var>, this command by +default creates it produces a single file +<samp><var>symbol-file</var>.gdb-index</samp>. If you invoke this command with +the <samp>-dwarf-5</samp> option, it produces 2 files: +<samp><var>symbol-file</var>.debug_names</samp> and +<samp><var>symbol-file</var>.debug_str</samp>. The files are created in the +given <var>directory</var>. +</p></dd> +</dl> + +<p>Once you have created an index file you can merge it into your symbol +file, here named <samp>symfile</samp>, using <code>objcopy</code>: +</p> +<div class="smallexample"> +<pre class="smallexample">$ objcopy --add-section .gdb_index=symfile.gdb-index \ + --set-section-flags .gdb_index=readonly symfile symfile +</pre></div> + +<p>Or for <code>-dwarf-5</code>: +</p> +<div class="smallexample"> +<pre class="smallexample">$ objcopy --dump-section .debug_str=symfile.debug_str.new symfile +$ cat symfile.debug_str >>symfile.debug_str.new +$ objcopy --add-section .debug_names=symfile.gdb-index \ + --set-section-flags .debug_names=readonly \ + --update-section .debug_str=symfile.debug_str.new symfile symfile +</pre></div> + +<p><small>GDB</small> will normally ignore older versions of <samp>.gdb_index</samp> +sections that have been deprecated. Usually they are deprecated because +they are missing a new feature or have performance issues. +To tell <small>GDB</small> to use a deprecated index section anyway +specify <code>set use-deprecated-index-sections on</code>. +The default is <code>off</code>. +This can speed up startup, but may result in some functionality being lost. +See <a href="Index-Section-Format.html#Index-Section-Format">Index Section Format</a>. +</p> +<p><em>Warning:</em> Setting <code>use-deprecated-index-sections</code> to <code>on</code> +must be done before gdb reads the file. The following will not work: +</p> +<div class="smallexample"> +<pre class="smallexample">$ gdb -ex "set use-deprecated-index-sections on" <program> +</pre></div> + +<p>Instead you must do, for example, +</p> +<div class="smallexample"> +<pre class="smallexample">$ gdb -iex "set use-deprecated-index-sections on" <program> +</pre></div> + +<p>Indices only work when using DWARF debugging information, not stabs. +</p> +<a name="Automatic-symbol-index-cache"></a> +<h4 class="subsection">18.5.1 Automatic symbol index cache</h4> + +<a name="index-automatic-symbol-index-cache"></a> +<p>It is possible for <small>GDB</small> to automatically save a copy of this index in a +cache on disk and retrieve it from there when loading the same binary in the +future. This feature can be turned on with <kbd>set index-cache enabled on</kbd>. +The following commands can be used to tweak the behavior of the index cache. +</p> +<dl compact="compact"> +<dd> +<a name="index-set-index_002dcache"></a> +</dd> +<dt><code>set index-cache enabled on</code></dt> +<dt><code>set index-cache enabled off</code></dt> +<dd><p>Enable or disable the use of the symbol index cache. +</p> +</dd> +<dt><code>set index-cache directory <var>directory</var></code></dt> +<dd><a name="index-show-index_002dcache"></a> +</dd> +<dt><code>show index-cache directory</code></dt> +<dd><p>Set/show the directory where index files will be saved. +</p> +<p>The default value for this directory depends on the host platform. On +most systems, the index is cached in the <samp>gdb</samp> subdirectory of +the directory pointed to by the <code>XDG_CACHE_HOME</code> environment +variable, if it is defined, else in the <samp>.cache/gdb</samp> subdirectory +of your home directory. However, on some systems, the default may +differ according to local convention. +</p> +<p>There is no limit on the disk space used by index cache. It is perfectly safe +to delete the content of that directory to free up disk space. +</p> +</dd> +<dt><code>show index-cache stats</code></dt> +<dd><p>Print the number of cache hits and misses since the launch of <small>GDB</small>. +</p> +</dd> +</dl> + +<hr> +<div class="header"> +<p> +Next: <a href="Symbol-Errors.html#Symbol-Errors" accesskey="n" rel="next">Symbol Errors</a>, Previous: <a href="MiniDebugInfo.html#MiniDebugInfo" accesskey="p" rel="previous">MiniDebugInfo</a>, Up: <a href="GDB-Files.html#GDB-Files" accesskey="u" rel="up">GDB Files</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> +</div> + + + +</body> +</html> |