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102 lines
4.7 KiB
HTML
102 lines
4.7 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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<!-- Copyright (C) 1992-2019 Free Software Foundation, Inc.
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Contributed by Cygnus Support. Written by Julia Menapace, Jim Kingdon,
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and David MacKenzie.
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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 or
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any later version published by the Free Software Foundation; with no
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Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
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Texts. A copy of the license is included in the section entitled "GNU
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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>Questions (STABS)</title>
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<meta name="description" content="Questions (STABS)">
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<meta name="keywords" content="Questions (STABS)">
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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="Symbol-Types-Index.html#Symbol-Types-Index" rel="index" title="Symbol Types Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="index.html#Top" rel="up" title="Top">
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<link href="Stab-Sections.html#Stab-Sections" rel="next" title="Stab Sections">
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<link href="N_005fLENG.html#N_005fLENG" rel="prev" title="N_LENG">
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<style type="text/css">
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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.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="Questions"></a>
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<div class="header">
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<p>
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Next: <a href="Stab-Sections.html#Stab-Sections" accesskey="n" rel="next">Stab Sections</a>, Previous: <a href="Expanded-Reference.html#Expanded-Reference" accesskey="p" rel="prev">Expanded Reference</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</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>
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</div>
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<hr>
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<a name="Questions-and-Anomalies"></a>
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<h2 class="appendix">Appendix E Questions and Anomalies</h2>
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<ul>
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<li> For GNU C stabs defining local and global variables (<code>N_LSYM</code> and
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<code>N_GSYM</code>), the desc field is supposed to contain the source
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line number on which the variable is defined. In reality the desc
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field is always 0. (This behavior is defined in <samp>dbxout.c</samp> and
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putting a line number in desc is controlled by ‘<samp>#ifdef
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WINNING_GDB</samp>’, which defaults to false). GDB supposedly uses this
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information if you say ‘<samp>list <var>var</var></samp>’. In reality, <var>var</var> can
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be a variable defined in the program and GDB says ‘<samp>function
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<var>var</var> not defined</samp>’.
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</li><li> In GNU C stabs, there seems to be no way to differentiate tag types:
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structures, unions, and enums (symbol descriptor ‘<samp>T</samp>’) and typedefs
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(symbol descriptor ‘<samp>t</samp>’) defined at file scope from types defined locally
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to a procedure or other more local scope. They all use the <code>N_LSYM</code>
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stab type. Types defined at procedure scope are emitted after the
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<code>N_RBRAC</code> of the preceding function and before the code of the
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procedure in which they are defined. This is exactly the same as
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types defined in the source file between the two procedure bodies.
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GDB over-compensates by placing all types in block #1, the block for
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symbols of file scope. This is true for default, ‘<samp>-ansi</samp>’ and
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‘<samp>-traditional</samp>’ compiler options. (Bugs gcc/1063, gdb/1066.)
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</li><li> What ends the procedure scope? Is it the proc block’s <code>N_RBRAC</code> or the
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next <code>N_FUN</code>? (I believe its the first.)
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</li></ul>
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</body>
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</html>
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