| <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> |
| <html> |
| <!-- This file documents the BFD library. |
| |
| Copyright (C) 1991 - 2013 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 "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. --> |
| <!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ --> |
| <head> |
| <title>Untitled Document: Adding symbols from an object file</title> |
| |
| <meta name="description" content="Untitled Document: Adding symbols from an object file"> |
| <meta name="keywords" content="Untitled Document: Adding symbols from an object file"> |
| <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="BFD-Index.html#BFD-Index" rel="index" title="BFD Index"> |
| <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> |
| <link href="Adding-Symbols-to-the-Hash-Table.html#Adding-Symbols-to-the-Hash-Table" rel="up" title="Adding Symbols to the Hash Table"> |
| <link href="Adding-symbols-from-an-archive.html#Adding-symbols-from-an-archive" rel="next" title="Adding symbols from an archive"> |
| <link href="Differing-file-formats.html#Differing-file-formats" rel="prev" title="Differing file formats"> |
| <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="Adding-symbols-from-an-object-file"></a> |
| <div class="header"> |
| <p> |
| Next: <a href="Adding-symbols-from-an-archive.html#Adding-symbols-from-an-archive" accesskey="n" rel="next">Adding symbols from an archive</a>, Previous: <a href="Differing-file-formats.html#Differing-file-formats" accesskey="p" rel="prev">Differing file formats</a>, Up: <a href="Adding-Symbols-to-the-Hash-Table.html#Adding-Symbols-to-the-Hash-Table" accesskey="u" rel="up">Adding Symbols to the Hash Table</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> |
| </div> |
| <hr> |
| <a name="Adding-symbols-from-an-object-file-1"></a> |
| <h4 class="subsubsection">2.17.2.2 Adding symbols from an object file</h4> |
| <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> |
| <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"></a> |
| <p><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> |
| <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> |
| <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. |
| </p> |
| <hr> |
| <div class="header"> |
| <p> |
| Next: <a href="Adding-symbols-from-an-archive.html#Adding-symbols-from-an-archive" accesskey="n" rel="next">Adding symbols from an archive</a>, Previous: <a href="Differing-file-formats.html#Differing-file-formats" accesskey="p" rel="prev">Differing file formats</a>, Up: <a href="Adding-Symbols-to-the-Hash-Table.html#Adding-Symbols-to-the-Hash-Table" accesskey="u" rel="up">Adding Symbols to the Hash Table</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> |
| </div> |
| |
| |
| |
| </body> |
| </html> |
