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106 lines
5.1 KiB
HTML
106 lines
5.1 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 GNU linker LD
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(SiFive Binutils 2.32.0-2020.04.1)
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version 2.32.
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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
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or any later version published by the Free Software Foundation;
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with no Invariant Sections, with no Front-Cover Texts, and with no
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Back-Cover Texts. A copy of the license is included in the
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section entitled "GNU Free Documentation License". -->
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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>Output Section Discarding (LD)</title>
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<meta name="description" content="Output Section Discarding (LD)">
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<meta name="keywords" content="Output Section Discarding (LD)">
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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="LD-Index.html#LD-Index" rel="index" title="LD Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="SECTIONS.html#SECTIONS" rel="up" title="SECTIONS">
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<link href="Output-Section-Attributes.html#Output-Section-Attributes" rel="next" title="Output Section Attributes">
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<link href="Output-Section-Keywords.html#Output-Section-Keywords" rel="prev" title="Output Section Keywords">
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<style type="text/css">
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<!--
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a.summary-letter {text-decoration: none}
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blockquote.indentedblock {margin-right: 0em}
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blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
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blockquote.smallquotation {font-size: smaller}
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div.display {margin-left: 3.2em}
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div.example {margin-left: 3.2em}
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div.lisp {margin-left: 3.2em}
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div.smalldisplay {margin-left: 3.2em}
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div.smallexample {margin-left: 3.2em}
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div.smalllisp {margin-left: 3.2em}
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kbd {font-style: oblique}
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pre.display {font-family: inherit}
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pre.format {font-family: inherit}
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pre.menu-comment {font-family: serif}
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pre.menu-preformatted {font-family: serif}
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pre.smalldisplay {font-family: inherit; font-size: smaller}
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pre.smallexample {font-size: smaller}
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pre.smallformat {font-family: inherit; font-size: smaller}
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pre.smalllisp {font-size: smaller}
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span.nolinebreak {white-space: nowrap}
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span.roman {font-family: initial; font-weight: normal}
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span.sansserif {font-family: sans-serif; font-weight: normal}
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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="Output-Section-Discarding"></a>
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<div class="header">
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<p>
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Next: <a href="Output-Section-Attributes.html#Output-Section-Attributes" accesskey="n" rel="next">Output Section Attributes</a>, Previous: <a href="Output-Section-Keywords.html#Output-Section-Keywords" accesskey="p" rel="prev">Output Section Keywords</a>, Up: <a href="SECTIONS.html#SECTIONS" accesskey="u" rel="up">SECTIONS</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>
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</div>
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<hr>
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<a name="Output-Section-Discarding-1"></a>
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<h4 class="subsection">3.6.7 Output Section Discarding</h4>
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<a name="index-discarding-sections"></a>
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<a name="index-sections_002c-discarding"></a>
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<a name="index-removing-sections"></a>
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<p>The linker will not normally create output sections with no contents.
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This is for convenience when referring to input sections that may or
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may not be present in any of the input files. For example:
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</p><div class="smallexample">
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<pre class="smallexample">.foo : { *(.foo) }
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</pre></div>
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<p>will only create a ‘<samp>.foo</samp>’ section in the output file if there is a
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‘<samp>.foo</samp>’ section in at least one input file, and if the input
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sections are not all empty. Other link script directives that allocate
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space in an output section will also create the output section. So
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too will assignments to dot even if the assignment does not create
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space, except for ‘<samp>. = 0</samp>’, ‘<samp>. = . + 0</samp>’, ‘<samp>. = sym</samp>’,
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‘<samp>. = . + sym</samp>’ and ‘<samp>. = ALIGN (. != 0, expr, 1)</samp>’ when
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‘<samp>sym</samp>’ is an absolute symbol of value 0 defined in the script.
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This allows you to force output of an empty section with ‘<samp>. = .</samp>’.
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</p>
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<p>The linker will ignore address assignments (see <a href="Output-Section-Address.html#Output-Section-Address">Output Section Address</a>)
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on discarded output sections, except when the linker script defines
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symbols in the output section. In that case the linker will obey
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the address assignments, possibly advancing dot even though the
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section is discarded.
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</p>
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<a name="index-_002fDISCARD_002f"></a>
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<p>The special output section name ‘<samp>/DISCARD/</samp>’ may be used to discard
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input sections. Any input sections which are assigned to an output
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section named ‘<samp>/DISCARD/</samp>’ are not included in the output file.
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</p>
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</body>
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</html>
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