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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/gdb/Using-Agent-Expressions.html | |
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
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diff --git a/share/doc/gdb/Using-Agent-Expressions.html b/share/doc/gdb/Using-Agent-Expressions.html new file mode 100644 index 0000000..744635f --- /dev/null +++ b/share/doc/gdb/Using-Agent-Expressions.html @@ -0,0 +1,124 @@ +<!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: Using Agent Expressions</title> + +<meta name="description" content="Debugging with GDB: Using Agent Expressions"> +<meta name="keywords" content="Debugging with GDB: Using Agent Expressions"> +<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="Agent-Expressions.html#Agent-Expressions" rel="up" title="Agent Expressions"> +<link href="Varying-Target-Capabilities.html#Varying-Target-Capabilities" rel="next" title="Varying Target Capabilities"> +<link href="Bytecode-Descriptions.html#Bytecode-Descriptions" rel="previous" title="Bytecode Descriptions"> +<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="Using-Agent-Expressions"></a> +<div class="header"> +<p> +Next: <a href="Varying-Target-Capabilities.html#Varying-Target-Capabilities" accesskey="n" rel="next">Varying Target Capabilities</a>, Previous: <a href="Bytecode-Descriptions.html#Bytecode-Descriptions" accesskey="p" rel="previous">Bytecode Descriptions</a>, Up: <a href="Agent-Expressions.html#Agent-Expressions" accesskey="u" rel="up">Agent Expressions</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="Using-Agent-Expressions-1"></a> +<h3 class="section">F.3 Using Agent Expressions</h3> + +<p>Agent expressions can be used in several different ways by <small>GDB</small>, +and the debugger can generate different bytecode sequences as appropriate. +</p> +<p>One possibility is to do expression evaluation on the target rather +than the host, such as for the conditional of a conditional +tracepoint. In such a case, <small>GDB</small> compiles the source +expression into a bytecode sequence that simply gets values from +registers or memory, does arithmetic, and returns a result. +</p> +<p>Another way to use agent expressions is for tracepoint data +collection. <small>GDB</small> generates a different bytecode sequence for +collection; in addition to bytecodes that do the calculation, +<small>GDB</small> adds <code>trace</code> bytecodes to save the pieces of +memory that were used. +</p> +<ul> +<li> The user selects trace points in the program’s code at which GDB should +collect data. + +</li><li> The user specifies expressions to evaluate at each trace point. These +expressions may denote objects in memory, in which case those objects’ +contents are recorded as the program runs, or computed values, in which +case the values themselves are recorded. + +</li><li> GDB transmits the tracepoints and their associated expressions to the +GDB agent, running on the debugging target. + +</li><li> The agent arranges to be notified when a trace point is hit. + +</li><li> When execution on the target reaches a trace point, the agent evaluates +the expressions associated with that trace point, and records the +resulting values and memory ranges. + +</li><li> Later, when the user selects a given trace event and inspects the +objects and expression values recorded, GDB talks to the agent to +retrieve recorded data as necessary to meet the user’s requests. If the +user asks to see an object whose contents have not been recorded, GDB +reports an error. + +</li></ul> + + +<hr> +<div class="header"> +<p> +Next: <a href="Varying-Target-Capabilities.html#Varying-Target-Capabilities" accesskey="n" rel="next">Varying Target Capabilities</a>, Previous: <a href="Bytecode-Descriptions.html#Bytecode-Descriptions" accesskey="p" rel="previous">Bytecode Descriptions</a>, Up: <a href="Agent-Expressions.html#Agent-Expressions" accesskey="u" rel="up">Agent Expressions</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> |