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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 | abdaadbcae30fe0c9a66c7516798279fdfd97750 (patch) | |
| tree | 00a54a6e25601e43876d03c1a4a12a749d4a914c /share/doc/stabs/String-Field.html | |
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
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diff --git a/share/doc/stabs/String-Field.html b/share/doc/stabs/String-Field.html new file mode 100644 index 0000000..84bb476 --- /dev/null +++ b/share/doc/stabs/String-Field.html @@ -0,0 +1,198 @@ +<!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: String Field</title> + +<meta name="description" content="STABS: String Field"> +<meta name="keywords" content="STABS: String Field"> +<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="Overview.html#Overview" rel="up" title="Overview"> +<link href="C-Example.html#C-Example" rel="next" title="C Example"> +<link href="Stabs-Format.html#Stabs-Format" rel="previous" title="Stabs Format"> +<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="String-Field"></a> +<div class="header"> +<p> +Next: <a href="C-Example.html#C-Example" accesskey="n" rel="next">C Example</a>, Previous: <a href="Stabs-Format.html#Stabs-Format" accesskey="p" rel="previous">Stabs Format</a>, Up: <a href="Overview.html#Overview" accesskey="u" rel="up">Overview</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="The-String-Field"></a> +<h3 class="section">1.3 The String Field</h3> + +<p>For most stabs the string field holds the meat of the +debugging information. The flexible nature of this field +is what makes stabs extensible. For some stab types the string field +contains only a name. For other stab types the contents can be a great +deal more complex. +</p> +<p>The overall format of the string field for most stab types is: +</p> +<div class="example"> +<pre class="example">"<var>name</var>:<var>symbol-descriptor</var> <var>type-information</var>" +</pre></div> + +<p><var>name</var> is the name of the symbol represented by the stab; it can +contain a pair of colons (see <a href="Nested-Symbols.html#Nested-Symbols">Nested Symbols</a>). <var>name</var> can be +omitted, which means the stab represents an unnamed object. For +example, ‘<samp>:t10=*2</samp>’ defines type 10 as a pointer to type 2, but does +not give the type a name. Omitting the <var>name</var> field is supported by +AIX dbx and GDB after about version 4.8, but not other debuggers. GCC +sometimes uses a single space as the name instead of omitting the name +altogether; apparently that is supported by most debuggers. +</p> +<p>The <var>symbol-descriptor</var> following the ‘<samp>:</samp>’ is an alphabetic +character that tells more specifically what kind of symbol the stab +represents. If the <var>symbol-descriptor</var> is omitted, but type +information follows, then the stab represents a local variable. For a +list of symbol descriptors, see <a href="Symbol-Descriptors.html#Symbol-Descriptors">Symbol Descriptors</a>. The ‘<samp>c</samp>’ +symbol descriptor is an exception in that it is not followed by type +information. See <a href="Constants.html#Constants">Constants</a>. +</p> +<p><var>type-information</var> is either a <var>type-number</var>, or +‘<samp><var>type-number</var>=</samp>’. A <var>type-number</var> alone is a type +reference, referring directly to a type that has already been defined. +</p> +<p>The ‘<samp><var>type-number</var>=</samp>’ form is a type definition, where the +number represents a new type which is about to be defined. The type +definition may refer to other types by number, and those type numbers +may be followed by ‘<samp>=</samp>’ and nested definitions. Also, the Lucid +compiler will repeat ‘<samp><var>type-number</var>=</samp>’ more than once if it +wants to define several type numbers at once. +</p> +<p>In a type definition, if the character that follows the equals sign is +non-numeric then it is a <var>type-descriptor</var>, and tells what kind of +type is about to be defined. Any other values following the +<var>type-descriptor</var> vary, depending on the <var>type-descriptor</var>. +See <a href="Type-Descriptors.html#Type-Descriptors">Type Descriptors</a>, for a list of <var>type-descriptor</var> values. If +a number follows the ‘<samp>=</samp>’ then the number is a <var>type-reference</var>. +For a full description of types, <a href="Types.html#Types">Types</a>. +</p> +<p>A <var>type-number</var> is often a single number. The GNU and Sun tools +additionally permit a <var>type-number</var> to be a pair +(<var>file-number</var>,<var>filetype-number</var>) (the parentheses appear in the +string, and serve to distinguish the two cases). The <var>file-number</var> +is 0 for the base source file, 1 for the first included file, 2 for the +next, and so on. The <var>filetype-number</var> is a number starting with +1 which is incremented for each new type defined in the file. +(Separating the file number and the type number permits the +<code>N_BINCL</code> optimization to succeed more often; see <a href="Include-Files.html#Include-Files">Include Files</a>). +</p> +<p>There is an AIX extension for type attributes. Following the ‘<samp>=</samp>’ +are any number of type attributes. Each one starts with ‘<samp>@</samp>’ and +ends with ‘<samp>;</samp>’. Debuggers, including AIX’s dbx and GDB 4.10, skip +any type attributes they do not recognize. GDB 4.9 and other versions +of dbx may not do this. Because of a conflict with C<tt>++</tt> +(see <a href="Cplusplus.html#Cplusplus">Cplusplus</a>), new attributes should not be defined which begin +with a digit, ‘<samp>(</samp>’, or ‘<samp>-</samp>’; GDB may be unable to distinguish +those from the C<tt>++</tt> type descriptor ‘<samp>@</samp>’. The attributes are: +</p> +<dl compact="compact"> +<dt><code>a<var>boundary</var></code></dt> +<dd><p><var>boundary</var> is an integer specifying the alignment. I assume it +applies to all variables of this type. +</p> +</dd> +<dt><code>p<var>integer</var></code></dt> +<dd><p>Pointer class (for checking). Not sure what this means, or how +<var>integer</var> is interpreted. +</p> +</dd> +<dt><code>P</code></dt> +<dd><p>Indicate this is a packed type, meaning that structure fields or array +elements are placed more closely in memory, to save memory at the +expense of speed. +</p> +</dd> +<dt><code>s<var>size</var></code></dt> +<dd><p>Size in bits of a variable of this type. This is fully supported by GDB +4.11 and later. +</p> +</dd> +<dt><code>S</code></dt> +<dd><p>Indicate that this type is a string instead of an array of characters, +or a bitstring instead of a set. It doesn’t change the layout of the +data being represented, but does enable the debugger to know which type +it is. +</p> +</dd> +<dt><code>V</code></dt> +<dd><p>Indicate that this type is a vector instead of an array. The only +major difference between vectors and arrays is that vectors are +passed by value instead of by reference (vector coprocessor extension). +</p> +</dd> +</dl> + +<p>All of this can make the string field quite long. All versions of GDB, +and some versions of dbx, can handle arbitrarily long strings. But many +versions of dbx (or assemblers or linkers, I’m not sure which) +cretinously limit the strings to about 80 characters, so compilers which +must work with such systems need to split the <code>.stabs</code> directive +into several <code>.stabs</code> directives. Each stab duplicates every field +except the string field. The string field of every stab except the last +is marked as continued with a backslash at the end (in the assembly code +this may be written as a double backslash, depending on the assembler). +Removing the backslashes and concatenating the string fields of each +stab produces the original, long string. Just to be incompatible (or so +they don’t have to worry about what the assembler does with +backslashes), AIX can use ‘<samp>?</samp>’ instead of backslash. +</p> +<hr> +<div class="header"> +<p> +Next: <a href="C-Example.html#C-Example" accesskey="n" rel="next">C Example</a>, Previous: <a href="Stabs-Format.html#Stabs-Format" accesskey="p" rel="previous">Stabs Format</a>, Up: <a href="Overview.html#Overview" accesskey="u" rel="up">Overview</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> |