74 lines
3.5 KiB
HTML
74 lines
3.5 KiB
HTML
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<html lang="en">
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<head>
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<title>Flow - STABS</title>
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<meta http-equiv="Content-Type" content="text/html">
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<meta name="description" content="STABS">
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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="Overview.html#Overview" title="Overview">
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<link rel="next" href="Stabs-Format.html#Stabs-Format" title="Stabs Format">
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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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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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<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="Flow"></a>
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<p>
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Next: <a rel="next" accesskey="n" href="Stabs-Format.html#Stabs-Format">Stabs Format</a>,
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Up: <a rel="up" accesskey="u" href="Overview.html#Overview">Overview</a>
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<hr>
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</div>
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<h3 class="section">1.1 Overview of Debugging Information Flow</h3>
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<p>The GNU C compiler compiles C source in a <samp><span class="file">.c</span></samp> file into assembly
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language in a <samp><span class="file">.s</span></samp> file, which the assembler translates into
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a <samp><span class="file">.o</span></samp> file, which the linker combines with other <samp><span class="file">.o</span></samp> files and
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libraries to produce an executable file.
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<p>With the ‘<samp><span class="samp">-g</span></samp>’ option, GCC puts in the <samp><span class="file">.s</span></samp> file additional
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debugging information, which is slightly transformed by the assembler
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and linker, and carried through into the final executable. This
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debugging information describes features of the source file like line
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numbers, the types and scopes of variables, and function names,
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parameters, and scopes.
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<p>For some object file formats, the debugging information is encapsulated
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in assembler directives known collectively as <dfn>stab</dfn> (symbol table)
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directives, which are interspersed with the generated code. Stabs are
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the native format for debugging information in the a.out and XCOFF
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object file formats. The GNU tools can also emit stabs in the COFF and
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ECOFF object file formats.
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<p>The assembler adds the information from stabs to the symbol information
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it places by default in the symbol table and the string table of the
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<samp><span class="file">.o</span></samp> file it is building. The linker consolidates the <samp><span class="file">.o</span></samp>
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files into one executable file, with one symbol table and one string
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table. Debuggers use the symbol and string tables in the executable as
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a source of debugging information about the program.
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</body></html>
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