77 lines
4.4 KiB
HTML
77 lines
4.4 KiB
HTML
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<html lang="en">
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<head>
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<title>Output Section Discarding - Untitled</title>
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<meta http-equiv="Content-Type" content="text/html">
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<meta name="description" content="Untitled">
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<meta name="generator" content="makeinfo 4.13">
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<link title="Top" rel="start" href="index.html#Top">
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<link rel="up" href="SECTIONS.html#SECTIONS" title="SECTIONS">
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<link rel="prev" href="Output-Section-Keywords.html#Output-Section-Keywords" title="Output Section Keywords">
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<link rel="next" href="Output-Section-Attributes.html#Output-Section-Attributes" title="Output Section Attributes">
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<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
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<!--
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This file documents the GNU linker LD
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(GNU Toolchain for the A-profile Architecture 9.2-2019.12 (arm-9.10))
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version 2.33.1.
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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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<style type="text/css"><!--
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--></style>
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</head>
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<body>
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<div class="node">
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<a name="Output-Section-Discarding"></a>
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<p>
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Next: <a rel="next" accesskey="n" href="Output-Section-Attributes.html#Output-Section-Attributes">Output Section Attributes</a>,
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Previous: <a rel="previous" accesskey="p" href="Output-Section-Keywords.html#Output-Section-Keywords">Output Section Keywords</a>,
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Up: <a rel="up" accesskey="u" href="SECTIONS.html#SECTIONS">SECTIONS</a>
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<hr>
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</div>
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<h4 class="subsection">3.6.7 Output Section Discarding</h4>
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<p><a name="index-discarding-sections-492"></a><a name="index-sections_002c-discarding-493"></a><a name="index-removing-sections-494"></a>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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<pre class="smallexample"> .foo : { *(.foo) }
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</pre>
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<p class="noindent">will only create a ‘<samp><span class="samp">.foo</span></samp>’ section in the output file if there is a
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‘<samp><span class="samp">.foo</span></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><span class="samp">. = 0</span></samp>’, ‘<samp><span class="samp">. = . + 0</span></samp>’, ‘<samp><span class="samp">. = sym</span></samp>’,
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‘<samp><span class="samp">. = . + sym</span></samp>’ and ‘<samp><span class="samp">. = ALIGN (. != 0, expr, 1)</span></samp>’ when
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‘<samp><span class="samp">sym</span></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><span class="samp">. = .</span></samp>’.
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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><a name="index-g_t_002fDISCARD_002f-495"></a>The special output section name ‘<samp><span class="samp">/DISCARD/</span></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><span class="samp">/DISCARD/</span></samp>’ are not included in the output file.
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</body></html>
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