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.
106 lines
5.2 KiB
HTML
106 lines
5.2 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) 1992-2019 Free Software Foundation, Inc.
|
||
|
|
Contributed by Cygnus Support. Written by Julia Menapace, Jim Kingdon,
|
||
|
|
and David MacKenzie.
|
||
|
|
|
||
|
|
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 no
|
||
|
|
Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
|
||
|
|
Texts. A copy of the license is included in the section entitled "GNU
|
||
|
|
Free Documentation License". -->
|
||
|
|
<!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ -->
|
||
|
|
<head>
|
||
|
|
<title>Transformations On Symbol Tables (STABS)</title>
|
||
|
|
|
||
|
|
<meta name="description" content="Transformations On Symbol Tables (STABS)">
|
||
|
|
<meta name="keywords" content="Transformations On Symbol Tables (STABS)">
|
||
|
|
<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="Symbol-Types-Index.html#Symbol-Types-Index" rel="index" title="Symbol Types Index">
|
||
|
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
||
|
|
<link href="Symbol-Tables.html#Symbol-Tables" rel="up" title="Symbol Tables">
|
||
|
|
<link href="Transformations-On-Static-Variables.html#Transformations-On-Static-Variables" rel="next" title="Transformations On Static Variables">
|
||
|
|
<link href="Symbol-Table-Format.html#Symbol-Table-Format" rel="prev" title="Symbol Table Format">
|
||
|
|
<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="Transformations-On-Symbol-Tables"></a>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Previous: <a href="Symbol-Table-Format.html#Symbol-Table-Format" accesskey="p" rel="prev">Symbol Table Format</a>, Up: <a href="Symbol-Tables.html#Symbol-Tables" accesskey="u" rel="up">Symbol Tables</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Symbol-Types-Index.html#Symbol-Types-Index" title="Index" rel="index">Index</a>]</p>
|
||
|
|
</div>
|
||
|
|
<hr>
|
||
|
|
<a name="Transformations-on-Symbol-Tables"></a>
|
||
|
|
<h3 class="section">7.2 Transformations on Symbol Tables</h3>
|
||
|
|
|
||
|
|
<p>The linker concatenates object files and does fixups of externally
|
||
|
|
defined symbols.
|
||
|
|
</p>
|
||
|
|
<p>You can see the transformations made on stab data by the assembler and
|
||
|
|
linker by examining the symbol table after each pass of the build. To
|
||
|
|
do this, use ‘<samp>nm -ap</samp>’, which dumps the symbol table, including
|
||
|
|
debugging information, unsorted. For stab entries the columns are:
|
||
|
|
<var>value</var>, <var>other</var>, <var>desc</var>, <var>type</var>, <var>string</var>. For
|
||
|
|
assembler and linker symbols, the columns are: <var>value</var>, <var>type</var>,
|
||
|
|
<var>string</var>.
|
||
|
|
</p>
|
||
|
|
<p>The low 5 bits of the stab type tell the linker how to relocate the
|
||
|
|
value of the stab. Thus for stab types like <code>N_RSYM</code> and
|
||
|
|
<code>N_LSYM</code>, where the value is an offset or a register number, the
|
||
|
|
low 5 bits are <code>N_ABS</code>, which tells the linker not to relocate the
|
||
|
|
value.
|
||
|
|
</p>
|
||
|
|
<p>Where the value of a stab contains an assembly language label,
|
||
|
|
it is transformed by each build step. The assembler turns it into a
|
||
|
|
relocatable address and the linker turns it into an absolute address.
|
||
|
|
</p>
|
||
|
|
<table class="menu" border="0" cellspacing="0">
|
||
|
|
<tr><td align="left" valign="top">• <a href="Transformations-On-Static-Variables.html#Transformations-On-Static-Variables" accesskey="1">Transformations On Static Variables</a>:</td><td> </td><td align="left" valign="top">
|
||
|
|
</td></tr>
|
||
|
|
<tr><td align="left" valign="top">• <a href="Transformations-On-Global-Variables.html#Transformations-On-Global-Variables" accesskey="2">Transformations On Global Variables</a>:</td><td> </td><td align="left" valign="top">
|
||
|
|
</td></tr>
|
||
|
|
<tr><td align="left" valign="top">• <a href="Stab-Section-Transformations.html#Stab-Section-Transformations" accesskey="3">Stab Section Transformations</a>:</td><td> </td><td align="left" valign="top">For some object file formats,
|
||
|
|
things are a bit different.
|
||
|
|
</td></tr>
|
||
|
|
</table>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|