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130 lines
6.2 KiB
HTML
130 lines
6.2 KiB
HTML
4 years ago
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<!-- This file documents the BFD library.
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Copyright (C) 1991-2019 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3 or
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any later version published by the Free Software Foundation; with the
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Invariant Sections being "GNU General Public License" and "Funding
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Free Software", the Front-Cover texts being (a) (see below), and with
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the Back-Cover Texts being (b) (see below). A copy of the license is
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included in the section entitled "GNU Free Documentation License".
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(a) The FSF's Front-Cover Text is:
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A GNU Manual
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(b) The FSF's Back-Cover Text is:
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You have freedom to copy and modify this GNU Manual, like GNU
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software. Copies published by the Free Software Foundation raise
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funds for GNU development. -->
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<!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ -->
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<head>
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<title>Linker Functions (Untitled Document)</title>
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<meta name="description" content="Linker Functions (Untitled Document)">
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<meta name="keywords" content="Linker Functions (Untitled Document)">
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<meta name="resource-type" content="document">
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<meta name="distribution" content="global">
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<meta name="Generator" content="makeinfo">
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<link href="index.html#Top" rel="start" title="Top">
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<link href="BFD-Index.html#BFD-Index" rel="index" title="BFD Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="BFD-front-end.html#BFD-front-end" rel="up" title="BFD front end">
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<link href="Creating-a-Linker-Hash-Table.html#Creating-a-Linker-Hash-Table" rel="next" title="Creating a Linker Hash Table">
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<link href="File-Caching.html#File-Caching" rel="prev" title="File Caching">
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<style type="text/css">
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ul.no-bullet {list-style: none}
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-->
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</style>
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</head>
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<body lang="en">
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<a name="Linker-Functions"></a>
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<div class="header">
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<p>
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Next: <a href="Hash-Tables.html#Hash-Tables" accesskey="n" rel="next">Hash Tables</a>, Previous: <a href="File-Caching.html#File-Caching" accesskey="p" rel="prev">File Caching</a>, Up: <a href="BFD-front-end.html#BFD-front-end" accesskey="u" rel="up">BFD front end</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="BFD-Index.html#BFD-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<a name="Linker-Functions-1"></a>
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<h3 class="section">2.17 Linker Functions</h3>
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<a name="index-Linker"></a>
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<p>The linker uses three special entry points in the BFD target
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vector. It is not necessary to write special routines for
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these entry points when creating a new BFD back end, since
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generic versions are provided. However, writing them can
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speed up linking and make it use significantly less runtime
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memory.
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</p>
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<p>The first routine creates a hash table used by the other
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routines. The second routine adds the symbols from an object
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file to the hash table. The third routine takes all the
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object files and links them together to create the output
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file. These routines are designed so that the linker proper
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does not need to know anything about the symbols in the object
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files that it is linking. The linker merely arranges the
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sections as directed by the linker script and lets BFD handle
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the details of symbols and relocs.
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</p>
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<p>The second routine and third routines are passed a pointer to
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a <code>struct bfd_link_info</code> structure (defined in
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<code>bfdlink.h</code>) which holds information relevant to the link,
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including the linker hash table (which was created by the
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first routine) and a set of callback functions to the linker
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proper.
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</p>
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<p>The generic linker routines are in <code>linker.c</code>, and use the
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header file <code>genlink.h</code>. As of this writing, the only back
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ends which have implemented versions of these routines are
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a.out (in <code>aoutx.h</code>) and ECOFF (in <code>ecoff.c</code>). The a.out
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routines are used as examples throughout this section.
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</p>
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<table class="menu" border="0" cellspacing="0">
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<tr><td align="left" valign="top">• <a href="Creating-a-Linker-Hash-Table.html#Creating-a-Linker-Hash-Table" accesskey="1">Creating a Linker Hash Table</a>:</td><td> </td><td align="left" valign="top">
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Adding-Symbols-to-the-Hash-Table.html#Adding-Symbols-to-the-Hash-Table" accesskey="2">Adding Symbols to the Hash Table</a>:</td><td> </td><td align="left" valign="top">
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Performing-the-Final-Link.html#Performing-the-Final-Link" accesskey="3">Performing the Final Link</a>:</td><td> </td><td align="left" valign="top">
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</td></tr>
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</table>
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<hr>
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<div class="header">
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<p>
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Next: <a href="Hash-Tables.html#Hash-Tables" accesskey="n" rel="next">Hash Tables</a>, Previous: <a href="File-Caching.html#File-Caching" accesskey="p" rel="prev">File Caching</a>, Up: <a href="BFD-front-end.html#BFD-front-end" accesskey="u" rel="up">BFD front end</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="BFD-Index.html#BFD-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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</body>
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</html>
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