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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/gdb/Source-Path.html | |
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
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diff --git a/share/doc/gdb/Source-Path.html b/share/doc/gdb/Source-Path.html new file mode 100644 index 0000000..e90a6fc --- /dev/null +++ b/share/doc/gdb/Source-Path.html @@ -0,0 +1,375 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 1988-2023 Free Software Foundation, Inc. + +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 the +Invariant Sections being "Free Software" and "Free Software Needs +Free Documentation", with the Front-Cover Texts being "A GNU Manual," +and with the Back-Cover Texts as in (a) below. + +(a) The FSF's Back-Cover Text is: "You are free to copy and modify +this GNU Manual. Buying copies from GNU Press supports the FSF in +developing GNU and promoting software freedom." --> +<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>Debugging with GDB: Source Path</title> + +<meta name="description" content="Debugging with GDB: Source Path"> +<meta name="keywords" content="Debugging with GDB: Source Path"> +<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="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="Source.html#Source" rel="up" title="Source"> +<link href="Machine-Code.html#Machine-Code" rel="next" title="Machine Code"> +<link href="Search.html#Search" rel="previous" title="Search"> +<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="Source-Path"></a> +<div class="header"> +<p> +Next: <a href="Machine-Code.html#Machine-Code" accesskey="n" rel="next">Machine Code</a>, Previous: <a href="Search.html#Search" accesskey="p" rel="previous">Search</a>, Up: <a href="Source.html#Source" accesskey="u" rel="up">Source</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<a name="Specifying-Source-Directories"></a> +<h3 class="section">9.5 Specifying Source Directories</h3> + +<a name="index-source-path"></a> +<a name="index-directories-for-source-files"></a> +<p>Executable programs sometimes do not record the directories of the source +files from which they were compiled, just the names. Even when they do, +the directories could be moved between the compilation and your debugging +session. <small>GDB</small> has a list of directories to search for source files; +this is called the <em>source path</em>. Each time <small>GDB</small> wants a source file, +it tries all the directories in the list, in the order they are present +in the list, until it finds a file with the desired name. +</p> +<p>For example, suppose an executable references the file +<samp>/usr/src/foo-1.0/lib/foo.c</samp>, does not record a compilation +directory, and the <em>source path</em> is <samp>/mnt/cross</samp>. +<small>GDB</small> would look for the source file in the following +locations: +</p> +<ol> +<li> <samp>/usr/src/foo-1.0/lib/foo.c</samp> +</li><li> <samp>/mnt/cross/usr/src/foo-1.0/lib/foo.c</samp> +</li><li> <samp>/mnt/cross/foo.c</samp> + +</li></ol> + +<p>If the source file is not present at any of the above locations then +an error is printed. <small>GDB</small> does not look up the parts of the +source file name, such as <samp>/mnt/cross/src/foo-1.0/lib/foo.c</samp>. +Likewise, the subdirectories of the source path are not searched: if +the source path is <samp>/mnt/cross</samp>, and the binary refers to +<samp>foo.c</samp>, <small>GDB</small> would not find it under +<samp>/mnt/cross/usr/src/foo-1.0/lib</samp>. +</p> +<p>Plain file names, relative file names with leading directories, file +names containing dots, etc. are all treated as described above, +except that non-absolute file names are not looked up literally. If +the <em>source path</em> is <samp>/mnt/cross</samp>, the source file is +recorded as <samp>../lib/foo.c</samp>, and no compilation directory is +recorded, then <small>GDB</small> will search in the following locations: +</p> +<ol> +<li> <samp>/mnt/cross/../lib/foo.c</samp> +</li><li> <samp>/mnt/cross/foo.c</samp> + +</li></ol> + +<a name="index-cdir"></a> +<a name="index-cwd"></a> +<a name="index-_0024cdir_002c-convenience-variable"></a> +<a name="index-_0024cwd_002c-convenience-variable"></a> +<a name="index-compilation-directory"></a> +<a name="index-current-directory"></a> +<a name="index-working-directory"></a> +<a name="index-directory_002c-current"></a> +<a name="index-directory_002c-compilation"></a> +<p>The <em>source path</em> will always include two special entries +‘<samp>$cdir</samp>’ and ‘<samp>$cwd</samp>’, these refer to the compilation directory +(if one is recorded) and the current working directory respectively. +</p> +<p>‘<samp>$cdir</samp>’ causes <small>GDB</small> to search within the compilation +directory, if one is recorded in the debug information. If no +compilation directory is recorded in the debug information then +‘<samp>$cdir</samp>’ is ignored. +</p> +<p>‘<samp>$cwd</samp>’ is not the same as ‘<samp>.</samp>’—the former tracks the +current working directory as it changes during your <small>GDB</small> +session, while the latter is immediately expanded to the current +directory at the time you add an entry to the source path. +</p> +<p>If a compilation directory is recorded in the debug information, and +<small>GDB</small> has not found the source file after the first search +using <em>source path</em>, then <small>GDB</small> will combine the +compilation directory and the filename, and then search for the source +file again using the <em>source path</em>. +</p> +<p>For example, if the executable records the source file as +<samp>/usr/src/foo-1.0/lib/foo.c</samp>, the compilation directory is +recorded as <samp>/project/build</samp>, and the <em>source path</em> is +<samp>/mnt/cross:$cdir:$cwd</samp> while the current working directory of +the <small>GDB</small> session is <samp>/home/user</samp>, then <small>GDB</small> will +search for the source file in the following locations: +</p> +<ol> +<li> <samp>/usr/src/foo-1.0/lib/foo.c</samp> +</li><li> <samp>/mnt/cross/usr/src/foo-1.0/lib/foo.c</samp> +</li><li> <samp>/project/build/usr/src/foo-1.0/lib/foo.c</samp> +</li><li> <samp>/home/user/usr/src/foo-1.0/lib/foo.c</samp> +</li><li> <samp>/mnt/cross/project/build/usr/src/foo-1.0/lib/foo.c</samp> +</li><li> <samp>/project/build/project/build/usr/src/foo-1.0/lib/foo.c</samp> +</li><li> <samp>/home/user/project/build/usr/src/foo-1.0/lib/foo.c</samp> +</li><li> <samp>/mnt/cross/foo.c</samp> +</li><li> <samp>/project/build/foo.c</samp> +</li><li> <samp>/home/user/foo.c</samp> + +</li></ol> + +<p>If the file name in the previous example had been recorded in the +executable as a relative path rather than an absolute path, then the +first look up would not have occurred, but all of the remaining steps +would be similar. +</p> +<p>When searching for source files on MS-DOS and MS-Windows, where +absolute paths start with a drive letter (e.g. +<samp>C:/project/foo.c</samp>), <small>GDB</small> will remove the drive letter +from the file name before appending it to a search directory from +<em>source path</em>; for instance if the executable references the +source file <samp>C:/project/foo.c</samp> and <em>source path</em> is set to +<samp>D:/mnt/cross</samp>, then <small>GDB</small> will search in the following +locations for the source file: +</p> +<ol> +<li> <samp>C:/project/foo.c</samp> +</li><li> <samp>D:/mnt/cross/project/foo.c</samp> +</li><li> <samp>D:/mnt/cross/foo.c</samp> + +</li></ol> + +<p>Note that the executable search path is <em>not</em> used to locate the +source files. +</p> +<p>Whenever you reset or rearrange the source path, <small>GDB</small> clears out +any information it has cached about where source files are found and where +each line is in the file. +</p> +<a name="index-directory"></a> +<a name="index-dir"></a> +<p>When you start <small>GDB</small>, its source path includes only ‘<samp>$cdir</samp>’ +and ‘<samp>$cwd</samp>’, in that order. +To add other directories, use the <code>directory</code> command. +</p> +<p>The search path is used to find both program source files and <small>GDB</small> +script files (read using the ‘<samp>-command</samp>’ option and ‘<samp>source</samp>’ command). +</p> +<p>In addition to the source path, <small>GDB</small> provides a set of commands +that manage a list of source path substitution rules. A <em>substitution +rule</em> specifies how to rewrite source directories stored in the program’s +debug information in case the sources were moved to a different +directory between compilation and debugging. A rule is made of +two strings, the first specifying what needs to be rewritten in +the path, and the second specifying how it should be rewritten. +In <a href="#set-substitute_002dpath">set substitute-path</a>, we name these two parts <var>from</var> and +<var>to</var> respectively. <small>GDB</small> does a simple string replacement +of <var>from</var> with <var>to</var> at the start of the directory part of the +source file name, and uses that result instead of the original file +name to look up the sources. +</p> +<p>Using the previous example, suppose the <samp>foo-1.0</samp> tree has been +moved from <samp>/usr/src</samp> to <samp>/mnt/cross</samp>, then you can tell +<small>GDB</small> to replace <samp>/usr/src</samp> in all source path names with +<samp>/mnt/cross</samp>. The first lookup will then be +<samp>/mnt/cross/foo-1.0/lib/foo.c</samp> in place of the original location +of <samp>/usr/src/foo-1.0/lib/foo.c</samp>. To define a source path +substitution rule, use the <code>set substitute-path</code> command +(see <a href="#set-substitute_002dpath">set substitute-path</a>). +</p> +<p>To avoid unexpected substitution results, a rule is applied only if the +<var>from</var> part of the directory name ends at a directory separator. +For instance, a rule substituting <samp>/usr/source</samp> into +<samp>/mnt/cross</samp> will be applied to <samp>/usr/source/foo-1.0</samp> but +not to <samp>/usr/sourceware/foo-2.0</samp>. And because the substitution +is applied only at the beginning of the directory name, this rule will +not be applied to <samp>/root/usr/source/baz.c</samp> either. +</p> +<p>In many cases, you can achieve the same result using the <code>directory</code> +command. However, <code>set substitute-path</code> can be more efficient in +the case where the sources are organized in a complex tree with multiple +subdirectories. With the <code>directory</code> command, you need to add each +subdirectory of your project. If you moved the entire tree while +preserving its internal organization, then <code>set substitute-path</code> +allows you to direct the debugger to all the sources with one single +command. +</p> +<p><code>set substitute-path</code> is also more than just a shortcut command. +The source path is only used if the file at the original location no +longer exists. On the other hand, <code>set substitute-path</code> modifies +the debugger behavior to look at the rewritten location instead. So, if +for any reason a source file that is not relevant to your executable is +located at the original location, a substitution rule is the only +method available to point <small>GDB</small> at the new location. +</p> +<a name="index-_002d_002dwith_002drelocated_002dsources"></a> +<a name="index-default-source-path-substitution"></a> +<p>You can configure a default source path substitution rule by +configuring <small>GDB</small> with the +‘<samp>--with-relocated-sources=<var>dir</var></samp>’ option. The <var>dir</var> +should be the name of a directory under <small>GDB</small>’s configured +prefix (set with ‘<samp>--prefix</samp>’ or ‘<samp>--exec-prefix</samp>’), and +directory names in debug information under <var>dir</var> will be adjusted +automatically if the installed <small>GDB</small> is moved to a new +location. This is useful if <small>GDB</small>, libraries or executables +with debug information and corresponding source code are being moved +together. +</p> +<dl compact="compact"> +<dt><code>directory <var>dirname</var> …</code></dt> +<dt><code>dir <var>dirname</var> …</code></dt> +<dd><p>Add directory <var>dirname</var> to the front of the source path. Several +directory names may be given to this command, separated by ‘<samp>:</samp>’ +(‘<samp>;</samp>’ on MS-DOS and MS-Windows, where ‘<samp>:</samp>’ usually appears as +part of absolute file names) or +whitespace. You may specify a directory that is already in the source +path; this moves it forward, so <small>GDB</small> searches it sooner. +</p> +<p>The special strings ‘<samp>$cdir</samp>’ (to refer to the compilation +directory, if one is recorded), and ‘<samp>$cwd</samp>’ (to refer to the +current working directory) can also be included in the list of +directories <var>dirname</var>. Though these will already be in the source +path they will be moved forward in the list so <small>GDB</small> searches +them sooner. +</p> +</dd> +<dt><code>directory</code></dt> +<dd><p>Reset the source path to its default value (‘<samp>$cdir:$cwd</samp>’ on Unix systems). This requires confirmation. +</p> + +</dd> +<dt><code>set directories <var>path-list</var></code></dt> +<dd><a name="index-set-directories"></a> +<p>Set the source path to <var>path-list</var>. +‘<samp>$cdir:$cwd</samp>’ are added if missing. +</p> +</dd> +<dt><code>show directories</code></dt> +<dd><a name="index-show-directories"></a> +<p>Print the source path: show which directories it contains. +</p> +<a name="set-substitute_002dpath"></a></dd> +<dt><code>set substitute-path <var>from</var> <var>to</var></code></dt> +<dd><a name="index-set-substitute_002dpath"></a> +<p>Define a source path substitution rule, and add it at the end of the +current list of existing substitution rules. If a rule with the same +<var>from</var> was already defined, then the old rule is also deleted. +</p> +<p>For example, if the file <samp>/foo/bar/baz.c</samp> was moved to +<samp>/mnt/cross/baz.c</samp>, then the command +</p> +<div class="smallexample"> +<pre class="smallexample">(gdb) set substitute-path /foo/bar /mnt/cross +</pre></div> + +<p>will tell <small>GDB</small> to replace ‘<samp>/foo/bar</samp>’ with +‘<samp>/mnt/cross</samp>’, which will allow <small>GDB</small> to find the file +<samp>baz.c</samp> even though it was moved. +</p> +<p>In the case when more than one substitution rule have been defined, +the rules are evaluated one by one in the order where they have been +defined. The first one matching, if any, is selected to perform +the substitution. +</p> +<p>For instance, if we had entered the following commands: +</p> +<div class="smallexample"> +<pre class="smallexample">(gdb) set substitute-path /usr/src/include /mnt/include +(gdb) set substitute-path /usr/src /mnt/src +</pre></div> + +<p><small>GDB</small> would then rewrite <samp>/usr/src/include/defs.h</samp> into +<samp>/mnt/include/defs.h</samp> by using the first rule. However, it would +use the second rule to rewrite <samp>/usr/src/lib/foo.c</samp> into +<samp>/mnt/src/lib/foo.c</samp>. +</p> + +</dd> +<dt><code>unset substitute-path [path]</code></dt> +<dd><a name="index-unset-substitute_002dpath"></a> +<p>If a path is specified, search the current list of substitution rules +for a rule that would rewrite that path. Delete that rule if found. +A warning is emitted by the debugger if no rule could be found. +</p> +<p>If no path is specified, then all substitution rules are deleted. +</p> +</dd> +<dt><code>show substitute-path [path]</code></dt> +<dd><a name="index-show-substitute_002dpath"></a> +<p>If a path is specified, then print the source path substitution rule +which would rewrite that path, if any. +</p> +<p>If no path is specified, then print all existing source path substitution +rules. +</p> +</dd> +</dl> + +<p>If your source path is cluttered with directories that are no longer of +interest, <small>GDB</small> may sometimes cause confusion by finding the wrong +versions of source. You can correct the situation as follows: +</p> +<ol> +<li> Use <code>directory</code> with no argument to reset the source path to its default value. + +</li><li> Use <code>directory</code> with suitable arguments to reinstall the +directories you want in the source path. You can add all the +directories in one command. +</li></ol> + +<hr> +<div class="header"> +<p> +Next: <a href="Machine-Code.html#Machine-Code" accesskey="n" rel="next">Machine Code</a>, Previous: <a href="Search.html#Search" accesskey="p" rel="previous">Search</a>, Up: <a href="Source.html#Source" accesskey="u" rel="up">Source</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> +</div> + + + +</body> +</html> |