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diff --git a/share/doc/gdb/Automatic-Overlay-Debugging.html b/share/doc/gdb/Automatic-Overlay-Debugging.html new file mode 100644 index 0000000..6415d64 --- /dev/null +++ b/share/doc/gdb/Automatic-Overlay-Debugging.html @@ -0,0 +1,140 @@ +<!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: Automatic Overlay Debugging</title> + +<meta name="description" content="Debugging with GDB: Automatic Overlay Debugging"> +<meta name="keywords" content="Debugging with GDB: Automatic Overlay Debugging"> +<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="Overlays.html#Overlays" rel="up" title="Overlays"> +<link href="Overlay-Sample-Program.html#Overlay-Sample-Program" rel="next" title="Overlay Sample Program"> +<link href="Overlay-Commands.html#Overlay-Commands" rel="previous" title="Overlay Commands"> +<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="Automatic-Overlay-Debugging"></a> +<div class="header"> +<p> +Next: <a href="Overlay-Sample-Program.html#Overlay-Sample-Program" accesskey="n" rel="next">Overlay Sample Program</a>, Previous: <a href="Overlay-Commands.html#Overlay-Commands" accesskey="p" rel="previous">Overlay Commands</a>, Up: <a href="Overlays.html#Overlays" accesskey="u" rel="up">Overlays</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="Automatic-Overlay-Debugging-1"></a> +<h3 class="section">14.3 Automatic Overlay Debugging</h3> +<a name="index-automatic-overlay-debugging"></a> + +<p><small>GDB</small> can automatically track which overlays are mapped and which +are not, given some simple co-operation from the overlay manager in the +inferior. If you enable automatic overlay debugging with the +<code>overlay auto</code> command (see <a href="Overlay-Commands.html#Overlay-Commands">Overlay Commands</a>), <small>GDB</small> +looks in the inferior’s memory for certain variables describing the +current state of the overlays. +</p> +<p>Here are the variables your overlay manager must define to support +<small>GDB</small>’s automatic overlay debugging: +</p> +<dl compact="compact"> +<dt><code>_ovly_table</code>:</dt> +<dd><p>This variable must be an array of the following structures: +</p> +<div class="smallexample"> +<pre class="smallexample">struct +{ + /* The overlay's mapped address. */ + unsigned long vma; + + /* The size of the overlay, in bytes. */ + unsigned long size; + + /* The overlay's load address. */ + unsigned long lma; + + /* Non-zero if the overlay is currently mapped; + zero otherwise. */ + unsigned long mapped; +} +</pre></div> + +</dd> +<dt><code>_novlys</code>:</dt> +<dd><p>This variable must be a four-byte signed integer, holding the total +number of elements in <code>_ovly_table</code>. +</p> +</dd> +</dl> + +<p>To decide whether a particular overlay is mapped or not, <small>GDB</small> +looks for an entry in <code><span class="nolinebreak">_ovly_table</span></code><!-- /@w --> whose <code>vma</code> and +<code>lma</code> members equal the VMA and LMA of the overlay’s section in the +executable file. When <small>GDB</small> finds a matching entry, it consults +the entry’s <code>mapped</code> member to determine whether the overlay is +currently mapped. +</p> +<p>In addition, your overlay manager may define a function called +<code>_ovly_debug_event</code>. If this function is defined, <small>GDB</small> +will silently set a breakpoint there. If the overlay manager then +calls this function whenever it has changed the overlay table, this +will enable <small>GDB</small> to accurately keep track of which overlays +are in program memory, and update any breakpoints that may be set +in overlays. This will allow breakpoints to work even if the +overlays are kept in ROM or other non-writable memory while they +are not being executed. +</p> +<hr> +<div class="header"> +<p> +Next: <a href="Overlay-Sample-Program.html#Overlay-Sample-Program" accesskey="n" rel="next">Overlay Sample Program</a>, Previous: <a href="Overlay-Commands.html#Overlay-Commands" accesskey="p" rel="previous">Overlay Commands</a>, Up: <a href="Overlays.html#Overlays" accesskey="u" rel="up">Overlays</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> |