97 lines
4.8 KiB
HTML
97 lines
4.8 KiB
HTML
|
<html lang="en">
|
||
|
|
<head>
|
||
|
|
<title>Adding symbols from an object file - Untitled</title>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html">
|
||
|
|
<meta name="description" content="Untitled">
|
||
|
|
<meta name="generator" content="makeinfo 4.7">
|
||
|
|
<link title="Top" rel="start" href="index.html#Top">
|
||
|
|
<link rel="up" href="Adding-Symbols-to-the-Hash-Table.html#Adding-Symbols-to-the-Hash-Table" title="Adding Symbols to the Hash Table">
|
||
|
|
<link rel="prev" href="Differing-file-formats.html#Differing-file-formats" title="Differing file formats">
|
||
|
|
<link rel="next" href="Adding-symbols-from-an-archive.html#Adding-symbols-from-an-archive" title="Adding symbols from an archive">
|
||
|
|
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
|
||
|
|
<!--
|
||
|
|
This file documents the BFD library.
|
||
|
|
|
||
|
|
Copyright (C) 1991, 2000, 2001, 2003, 2006, 2007 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 1.1 or
|
||
|
|
any later version published by the Free Software Foundation; with the
|
||
|
|
Invariant Sections being ``GNU General Public License'' and ``Funding
|
||
|
|
Free Software'', the Front-Cover texts being (a) (see below), and with
|
||
|
|
the Back-Cover Texts being (b) (see below). A copy of the license is
|
||
|
|
included in the section entitled ``GNU Free Documentation License''.
|
||
|
|
|
||
|
|
(a) The FSF's Front-Cover Text is:
|
||
|
|
|
||
|
|
A GNU Manual
|
||
|
|
|
||
|
|
(b) The FSF's Back-Cover Text is:
|
||
|
|
|
||
|
|
You have freedom to copy and modify this GNU Manual, like GNU
|
||
|
|
software. Copies published by the Free Software Foundation raise
|
||
|
|
funds for GNU development.-->
|
||
|
|
<meta http-equiv="Content-Style-Type" content="text/css">
|
||
|
|
<style type="text/css"><!--
|
||
|
|
pre.display { font-family:inherit }
|
||
|
|
pre.format { font-family:inherit }
|
||
|
|
pre.smalldisplay { font-family:inherit; font-size:smaller }
|
||
|
|
pre.smallformat { font-family:inherit; font-size:smaller }
|
||
|
|
pre.smallexample { font-size:smaller }
|
||
|
|
pre.smalllisp { font-size:smaller }
|
||
|
|
span.sc { font-variant:small-caps }
|
||
|
|
span.roman { font-family: serif; font-weight: normal; }
|
||
|
|
--></style>
|
||
|
|
</head>
|
||
|
|
<body>
|
||
|
|
<div class="node">
|
||
|
|
<p>
|
||
|
|
<a name="Adding-symbols-from-an-object-file"></a>Next: <a rel="next" accesskey="n" href="Adding-symbols-from-an-archive.html#Adding-symbols-from-an-archive">Adding symbols from an archive</a>,
|
||
|
|
Previous: <a rel="previous" accesskey="p" href="Differing-file-formats.html#Differing-file-formats">Differing file formats</a>,
|
||
|
|
Up: <a rel="up" accesskey="u" href="Adding-Symbols-to-the-Hash-Table.html#Adding-Symbols-to-the-Hash-Table">Adding Symbols to the Hash Table</a>
|
||
|
|
<hr><br>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
<h5 class="subsubsection">2.17.2.2 Adding symbols from an object file</h5>
|
||
|
|
|
||
|
|
<p>When the <code>_bfd_link_add_symbols</code> routine is passed an object
|
||
|
|
file, it must add all externally visible symbols in that
|
||
|
|
object file to the hash table. The actual work of adding the
|
||
|
|
symbol to the hash table is normally handled by the function
|
||
|
|
<code>_bfd_generic_link_add_one_symbol</code>. The
|
||
|
|
<code>_bfd_link_add_symbols</code> routine is responsible for reading
|
||
|
|
all the symbols from the object file and passing the correct
|
||
|
|
information to <code>_bfd_generic_link_add_one_symbol</code>.
|
||
|
|
|
||
|
|
<p>The <code>_bfd_link_add_symbols</code> routine should not use
|
||
|
|
<code>bfd_canonicalize_symtab</code> to read the symbols. The point of
|
||
|
|
providing this routine is to avoid the overhead of converting
|
||
|
|
the symbols into generic <code>asymbol</code> structures.
|
||
|
|
|
||
|
|
<p><a name="index-_005fbfd_005fgeneric_005flink_005fadd_005fone_005fsymbol-1373"></a><code>_bfd_generic_link_add_one_symbol</code> handles the details of
|
||
|
|
combining common symbols, warning about multiple definitions,
|
||
|
|
and so forth. It takes arguments which describe the symbol to
|
||
|
|
add, notably symbol flags, a section, and an offset. The
|
||
|
|
symbol flags include such things as <code>BSF_WEAK</code> or
|
||
|
|
<code>BSF_INDIRECT</code>. The section is a section in the object
|
||
|
|
file, or something like <code>bfd_und_section_ptr</code> for an undefined
|
||
|
|
symbol or <code>bfd_com_section_ptr</code> for a common symbol.
|
||
|
|
|
||
|
|
<p>If the <code>_bfd_final_link</code> routine is also going to need to
|
||
|
|
read the symbol information, the <code>_bfd_link_add_symbols</code>
|
||
|
|
routine should save it somewhere attached to the object file
|
||
|
|
BFD. However, the information should only be saved if the
|
||
|
|
<code>keep_memory</code> field of the <code>info</code> argument is TRUE, so
|
||
|
|
that the <code>-no-keep-memory</code> linker switch is effective.
|
||
|
|
|
||
|
|
<p>The a.out function which adds symbols from an object file is
|
||
|
|
<code>aout_link_add_object_symbols</code>, and most of the interesting
|
||
|
|
work is in <code>aout_link_add_symbols</code>. The latter saves
|
||
|
|
pointers to the hash tables entries created by
|
||
|
|
<code>_bfd_generic_link_add_one_symbol</code> indexed by symbol number,
|
||
|
|
so that the <code>_bfd_final_link</code> routine does not have to call
|
||
|
|
the hash table lookup routine to locate the entry.
|
||
|
|
|
||
|
|
</body></html>
|
||
|
|
|