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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/Inheritance.html | |
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
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diff --git a/share/doc/stabs/Inheritance.html b/share/doc/stabs/Inheritance.html new file mode 100644 index 0000000..ad2e79d --- /dev/null +++ b/share/doc/stabs/Inheritance.html @@ -0,0 +1,179 @@ +<!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: Inheritance</title> + +<meta name="description" content="STABS: Inheritance"> +<meta name="keywords" content="STABS: Inheritance"> +<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="Cplusplus.html#Cplusplus" rel="up" title="Cplusplus"> +<link href="Virtual-Base-Classes.html#Virtual-Base-Classes" rel="next" title="Virtual Base Classes"> +<link href="Virtual-Methods.html#Virtual-Methods" rel="previous" title="Virtual Methods"> +<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="Inheritance"></a> +<div class="header"> +<p> +Next: <a href="Virtual-Base-Classes.html#Virtual-Base-Classes" accesskey="n" rel="next">Virtual Base Classes</a>, Previous: <a href="Virtual-Methods.html#Virtual-Methods" accesskey="p" rel="previous">Virtual Methods</a>, Up: <a href="Cplusplus.html#Cplusplus" accesskey="u" rel="up">Cplusplus</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="Inheritance-1"></a> +<h3 class="section">8.12 Inheritance</h3> + +<p>Stabs describing C<tt>++</tt> derived classes include additional sections that +describe the inheritance hierarchy of the class. A derived class stab +also encodes the number of base classes. For each base class it tells +if the base class is virtual or not, and if the inheritance is private +or public. It also gives the offset into the object of the portion of +the object corresponding to each base class. +</p> +<p>This additional information is embedded in the class stab following the +number of bytes in the struct. First the number of base classes +appears bracketed by an exclamation point and a comma. +</p> +<p>Then for each base type there repeats a series: a virtual character, a +visibility character, a number, a comma, another number, and a +semi-colon. +</p> +<p>The virtual character is ‘<samp>1</samp>’ if the base class is virtual and +‘<samp>0</samp>’ if not. The visibility character is ‘<samp>2</samp>’ if the derivation +is public, ‘<samp>1</samp>’ if it is protected, and ‘<samp>0</samp>’ if it is private. +Debuggers should ignore virtual or visibility characters they do not +recognize, and assume a reasonable default (such as public and +non-virtual) (GDB 4.11 does not, but this should be fixed in the next +GDB release). +</p> +<p>The number following the virtual and visibility characters is the offset +from the start of the object to the part of the object pertaining to the +base class. +</p> +<p>After the comma, the second number is a type_descriptor for the base +type. Finally a semi-colon ends the series, which repeats for each +base class. +</p> +<p>The source below defines three base classes <code>A</code>, <code>B</code>, and +<code>C</code> and the derived class <code>D</code>. +</p> + +<div class="example"> +<pre class="example">class A { +public: + int Adat; + virtual int A_virt (int arg) { return arg; }; +}; + +class B { +public: + int B_dat; + virtual int B_virt (int arg) {return arg; }; +}; + +class C { +public: + int Cdat; + virtual int C_virt (int arg) {return arg; }; +}; + +class D : A, virtual B, public C { +public: + int Ddat; + virtual int A_virt (int arg ) { return arg+1; }; + virtual int B_virt (int arg) { return arg+2; }; + virtual int C_virt (int arg) { return arg+3; }; + virtual int D_virt (int arg) { return arg; }; +}; +</pre></div> + +<p>Class stabs similar to the ones described earlier are generated for +each base class. +</p> +<div class="smallexample"> +<pre class="smallexample">.stabs "A:T20=s8Adat:1,0,32;$vf20:21=*22=ar1;0;1;17,32; + A_virt::23=##1;:i;2A*-2147483647;20;;;~%20;",128,0,0,0 + +.stabs "B:Tt25=s8Bdat:1,0,32;$vf25:21,32;B_virt::26=##1; + :i;2A*-2147483647;25;;;~%25;",128,0,0,0 + +.stabs "C:Tt28=s8Cdat:1,0,32;$vf28:21,32;C_virt::29=##1; + :i;2A*-2147483647;28;;;~%28;",128,0,0,0 +</pre></div> + +<p>In the stab describing derived class <code>D</code> below, the information about +the derivation of this class is encoded as follows. +</p> +<div class="display"> +<pre class="display">.stabs "derived_class_name:symbol_descriptors(struct tag&type)= + type_descriptor(struct)struct_bytes(32)!num_bases(3), + base_virtual(no)inheritance_public(no)base_offset(0), + base_class_type_ref(A); + base_virtual(yes)inheritance_public(no)base_offset(NIL), + base_class_type_ref(B); + base_virtual(no)inheritance_public(yes)base_offset(64), + base_class_type_ref(C); … +</pre></div> + +<div class="smallexample"> +<pre class="smallexample">.stabs "D:Tt31=s32!3,000,20;100,25;0264,28;$vb25:24,128;Ddat: + 1,160,32;A_virt::32=##1;:i;2A*-2147483647;20;;B_virt: + :32:i;2A*-2147483647;25;;C_virt::32:i;2A*-2147483647; + 28;;D_virt::32:i;2A*-2147483646;31;;;~%20;",128,0,0,0 +</pre></div> + +<hr> +<div class="header"> +<p> +Next: <a href="Virtual-Base-Classes.html#Virtual-Base-Classes" accesskey="n" rel="next">Virtual Base Classes</a>, Previous: <a href="Virtual-Methods.html#Virtual-Methods" accesskey="p" rel="previous">Virtual Methods</a>, Up: <a href="Cplusplus.html#Cplusplus" accesskey="u" rel="up">Cplusplus</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> + + + +</body> +</html> |