You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
130 lines
5.4 KiB
HTML
130 lines
5.4 KiB
HTML
4 years ago
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||
|
|
<html>
|
||
|
|
<!-- Copyright (C) 1988-2019 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 6.4, http://www.gnu.org/software/texinfo/ -->
|
||
|
|
<head>
|
||
|
|
<title>Overlay Sample Program (Debugging with GDB)</title>
|
||
|
|
|
||
|
|
<meta name="description" content="Overlay Sample Program (Debugging with GDB)">
|
||
|
|
<meta name="keywords" content="Overlay Sample Program (Debugging with GDB)">
|
||
|
|
<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="Languages.html#Languages" rel="next" title="Languages">
|
||
|
|
<link href="Automatic-Overlay-Debugging.html#Automatic-Overlay-Debugging" rel="prev" title="Automatic Overlay Debugging">
|
||
|
|
<style type="text/css">
|
||
|
|
<!--
|
||
|
|
a.summary-letter {text-decoration: none}
|
||
|
|
blockquote.indentedblock {margin-right: 0em}
|
||
|
|
blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
|
||
|
|
blockquote.smallquotation {font-size: smaller}
|
||
|
|
div.display {margin-left: 3.2em}
|
||
|
|
div.example {margin-left: 3.2em}
|
||
|
|
div.lisp {margin-left: 3.2em}
|
||
|
|
div.smalldisplay {margin-left: 3.2em}
|
||
|
|
div.smallexample {margin-left: 3.2em}
|
||
|
|
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.nolinebreak {white-space: nowrap}
|
||
|
|
span.roman {font-family: initial; font-weight: normal}
|
||
|
|
span.sansserif {font-family: sans-serif; font-weight: normal}
|
||
|
|
ul.no-bullet {list-style: none}
|
||
|
|
-->
|
||
|
|
</style>
|
||
|
|
|
||
|
|
|
||
|
|
</head>
|
||
|
|
|
||
|
|
<body lang="en">
|
||
|
|
<a name="Overlay-Sample-Program"></a>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Previous: <a href="Automatic-Overlay-Debugging.html#Automatic-Overlay-Debugging" accesskey="p" rel="prev">Automatic Overlay Debugging</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="Overlay-Sample-Program-1"></a>
|
||
|
|
<h3 class="section">14.4 Overlay Sample Program</h3>
|
||
|
|
<a name="index-overlay-example-program"></a>
|
||
|
|
|
||
|
|
<p>When linking a program which uses overlays, you must place the overlays
|
||
|
|
at their load addresses, while relocating them to run at their mapped
|
||
|
|
addresses. To do this, you must write a linker script (see <a href="http://sourceware.org/binutils/docs/ld/Overlay-Description.html#Overlay-Description">Overlay
|
||
|
|
Description</a> in <cite>Using ld: the GNU linker</cite>). Unfortunately,
|
||
|
|
since linker scripts are specific to a particular host system, target
|
||
|
|
architecture, and target memory layout, this manual cannot provide
|
||
|
|
portable sample code demonstrating <small>GDB</small>’s overlay support.
|
||
|
|
</p>
|
||
|
|
<p>However, the <small>GDB</small> source distribution does contain an overlaid
|
||
|
|
program, with linker scripts for a few systems, as part of its test
|
||
|
|
suite. The program consists of the following files from
|
||
|
|
<samp>gdb/testsuite/gdb.base</samp>:
|
||
|
|
</p>
|
||
|
|
<dl compact="compact">
|
||
|
|
<dt><samp>overlays.c</samp></dt>
|
||
|
|
<dd><p>The main program file.
|
||
|
|
</p></dd>
|
||
|
|
<dt><samp>ovlymgr.c</samp></dt>
|
||
|
|
<dd><p>A simple overlay manager, used by <samp>overlays.c</samp>.
|
||
|
|
</p></dd>
|
||
|
|
<dt><samp>foo.c</samp></dt>
|
||
|
|
<dt><samp>bar.c</samp></dt>
|
||
|
|
<dt><samp>baz.c</samp></dt>
|
||
|
|
<dt><samp>grbx.c</samp></dt>
|
||
|
|
<dd><p>Overlay modules, loaded and used by <samp>overlays.c</samp>.
|
||
|
|
</p></dd>
|
||
|
|
<dt><samp>d10v.ld</samp></dt>
|
||
|
|
<dt><samp>m32r.ld</samp></dt>
|
||
|
|
<dd><p>Linker scripts for linking the test program on the <code>d10v-elf</code>
|
||
|
|
and <code>m32r-elf</code> targets.
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<p>You can build the test program using the <code>d10v-elf</code> GCC
|
||
|
|
cross-compiler like this:
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample">$ d10v-elf-gcc -g -c overlays.c
|
||
|
|
$ d10v-elf-gcc -g -c ovlymgr.c
|
||
|
|
$ d10v-elf-gcc -g -c foo.c
|
||
|
|
$ d10v-elf-gcc -g -c bar.c
|
||
|
|
$ d10v-elf-gcc -g -c baz.c
|
||
|
|
$ d10v-elf-gcc -g -c grbx.c
|
||
|
|
$ d10v-elf-gcc -g overlays.o ovlymgr.o foo.o bar.o \
|
||
|
|
baz.o grbx.o -Wl,-Td10v.ld -o overlays
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>The build process is identical for any other architecture, except that
|
||
|
|
you must substitute the appropriate compiler and linker script for the
|
||
|
|
target system for <code>d10v-elf-gcc</code> and <code>d10v.ld</code>.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|