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| author | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
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| committer | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
| commit | 6ce4ebed87858ecdd79a1091367c6e961055daa9 (patch) | |
| tree | 1c2a6a60531acf791531bbd9c8ac14c23ef8a66c /share/doc/stabs/Stack-Variables.html | |
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
Change-Id: I7303388733328cd98ab9aa3c30236db67f2e9e9c
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diff --git a/share/doc/stabs/Stack-Variables.html b/share/doc/stabs/Stack-Variables.html new file mode 100644 index 0000000..004dc7e --- /dev/null +++ b/share/doc/stabs/Stack-Variables.html @@ -0,0 +1,119 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 1992-2023 Free Software Foundation, Inc. +Contributed by Cygnus Support. Written by Julia Menapace, Jim Kingdon, +and David MacKenzie. + +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 no +Invariant Sections, with no Front-Cover Texts, and with no Back-Cover +Texts. A copy of the license is included in the section entitled "GNU +Free Documentation License". --> +<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>STABS: Stack Variables</title> + +<meta name="description" content="STABS: Stack Variables"> +<meta name="keywords" content="STABS: Stack Variables"> +<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="Symbol-Types-Index.html#Symbol-Types-Index" rel="index" title="Symbol Types Index"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="Variables.html#Variables" rel="up" title="Variables"> +<link href="Global-Variables.html#Global-Variables" rel="next" title="Global Variables"> +<link href="Variables.html#Variables" rel="previous" title="Variables"> +<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="Stack-Variables"></a> +<div class="header"> +<p> +Next: <a href="Global-Variables.html#Global-Variables" accesskey="n" rel="next">Global Variables</a>, Up: <a href="Variables.html#Variables" accesskey="u" rel="up">Variables</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Symbol-Types-Index.html#Symbol-Types-Index" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<a name="Automatic-Variables-Allocated-on-the-Stack"></a> +<h3 class="section">4.1 Automatic Variables Allocated on the Stack</h3> + +<p>If a variable’s scope is local to a function and its lifetime is only as +long as that function executes (C calls such variables +<em>automatic</em>), it can be allocated in a register (see <a href="Register-Variables.html#Register-Variables">Register Variables</a>) or on the stack. +</p> +<a name="index-N_005fLSYM_002c-for-stack-variables"></a> +<a name="index-C_005fLSYM"></a> +<p>Each variable allocated on the stack has a stab with the symbol +descriptor omitted. Since type information should begin with a digit, +‘<samp>-</samp>’, or ‘<samp>(</samp>’, only those characters precluded from being used +for symbol descriptors. However, the Acorn RISC machine (ARM) is said +to get this wrong: it puts out a mere type definition here, without the +preceding ‘<samp><var>type-number</var>=</samp>’. This is a bad idea; there is no +guarantee that type descriptors are distinct from symbol descriptors. +Stabs for stack variables use the <code>N_LSYM</code> stab type, or +<code>C_LSYM</code> for XCOFF. +</p> +<p>The value of the stab is the offset of the variable within the +local variables. On most machines this is an offset from the frame +pointer and is negative. The location of the stab specifies which block +it is defined in; see <a href="Block-Structure.html#Block-Structure">Block Structure</a>. +</p> +<p>For example, the following C code: +</p> +<div class="example"> +<pre class="example">int +main () +{ + int x; +} +</pre></div> + +<p>produces the following stabs: +</p> +<div class="example"> +<pre class="example">.stabs "main:F1",36,0,0,_main # <span class="roman">36 is N_FUN</span> +.stabs "x:1",128,0,0,-12 # <span class="roman">128 is N_LSYM</span> +.stabn 192,0,0,LBB2 # <span class="roman">192 is N_LBRAC</span> +.stabn 224,0,0,LBE2 # <span class="roman">224 is N_RBRAC</span> +</pre></div> + +<p>See <a href="Procedures.html#Procedures">Procedures</a> for more information on the <code>N_FUN</code> stab, and +<a href="Block-Structure.html#Block-Structure">Block Structure</a> for more information on the <code>N_LBRAC</code> and +<code>N_RBRAC</code> stabs. +</p> + + + +</body> +</html> |