111 lines
5.0 KiB
HTML
111 lines
5.0 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
|
<html>
|
|
<!-- This file documents the GNU linker LD
|
|
(Linaro_Binutils-2017.02)
|
|
version 2.27.0.
|
|
|
|
Copyright (C) 1991-2016 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 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 5.2, http://www.gnu.org/software/texinfo/ -->
|
|
<head>
|
|
<title>LD: Input Section Common</title>
|
|
|
|
<meta name="description" content="LD: Input Section Common">
|
|
<meta name="keywords" content="LD: Input Section Common">
|
|
<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="LD-Index.html#LD-Index" rel="index" title="LD Index">
|
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
|
<link href="Input-Section.html#Input-Section" rel="up" title="Input Section">
|
|
<link href="Input-Section-Keep.html#Input-Section-Keep" rel="next" title="Input Section Keep">
|
|
<link href="Input-Section-Wildcards.html#Input-Section-Wildcards" rel="prev" title="Input Section Wildcards">
|
|
<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="Input-Section-Common"></a>
|
|
<div class="header">
|
|
<p>
|
|
Next: <a href="Input-Section-Keep.html#Input-Section-Keep" accesskey="n" rel="next">Input Section Keep</a>, Previous: <a href="Input-Section-Wildcards.html#Input-Section-Wildcards" accesskey="p" rel="prev">Input Section Wildcards</a>, Up: <a href="Input-Section.html#Input-Section" accesskey="u" rel="up">Input Section</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="LD-Index.html#LD-Index" title="Index" rel="index">Index</a>]</p>
|
|
</div>
|
|
<hr>
|
|
<a name="Input-Section-for-Common-Symbols"></a>
|
|
<h4 class="subsubsection">3.6.4.3 Input Section for Common Symbols</h4>
|
|
<a name="index-common-symbol-placement"></a>
|
|
<a name="index-uninitialized-data-placement"></a>
|
|
<p>A special notation is needed for common symbols, because in many object
|
|
file formats common symbols do not have a particular input section. The
|
|
linker treats common symbols as though they are in an input section
|
|
named ‘<samp>COMMON</samp>’.
|
|
</p>
|
|
<p>You may use file names with the ‘<samp>COMMON</samp>’ section just as with any
|
|
other input sections. You can use this to place common symbols from a
|
|
particular input file in one section while common symbols from other
|
|
input files are placed in another section.
|
|
</p>
|
|
<p>In most cases, common symbols in input files will be placed in the
|
|
‘<samp>.bss</samp>’ section in the output file. For example:
|
|
</p><div class="smallexample">
|
|
<pre class="smallexample">.bss { *(.bss) *(COMMON) }
|
|
</pre></div>
|
|
|
|
<a name="index-scommon-section"></a>
|
|
<a name="index-small-common-symbols"></a>
|
|
<p>Some object file formats have more than one type of common symbol. For
|
|
example, the MIPS ELF object file format distinguishes standard common
|
|
symbols and small common symbols. In this case, the linker will use a
|
|
different special section name for other types of common symbols. In
|
|
the case of MIPS ELF, the linker uses ‘<samp>COMMON</samp>’ for standard common
|
|
symbols and ‘<samp>.scommon</samp>’ for small common symbols. This permits you
|
|
to map the different types of common symbols into memory at different
|
|
locations.
|
|
</p>
|
|
<a name="index-_005bCOMMON_005d"></a>
|
|
<p>You will sometimes see ‘<samp>[COMMON]</samp>’ in old linker scripts. This
|
|
notation is now considered obsolete. It is equivalent to
|
|
‘<samp>*(COMMON)</samp>’.
|
|
</p>
|
|
|
|
|
|
|
|
</body>
|
|
</html>
|