You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
132 lines
6.2 KiB
HTML
132 lines
6.2 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
|
<html>
|
|
<!-- Copyright (C) 1988-2019 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 6.4, http://www.gnu.org/software/texinfo/ -->
|
|
<head>
|
|
<title>Breakpoint-related Warnings (Debugging with GDB)</title>
|
|
|
|
<meta name="description" content="Breakpoint-related Warnings (Debugging with GDB)">
|
|
<meta name="keywords" content="Breakpoint-related Warnings (Debugging with GDB)">
|
|
<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="Breakpoints.html#Breakpoints" rel="up" title="Breakpoints">
|
|
<link href="Continuing-and-Stepping.html#Continuing-and-Stepping" rel="next" title="Continuing and Stepping">
|
|
<link href="Error-in-Breakpoints.html#Error-in-Breakpoints" rel="prev" title="Error in Breakpoints">
|
|
<style type="text/css">
|
|
<!--
|
|
a.summary-letter {text-decoration: none}
|
|
blockquote.indentedblock {margin-right: 0em}
|
|
blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
|
|
blockquote.smallquotation {font-size: smaller}
|
|
div.display {margin-left: 3.2em}
|
|
div.example {margin-left: 3.2em}
|
|
div.lisp {margin-left: 3.2em}
|
|
div.smalldisplay {margin-left: 3.2em}
|
|
div.smallexample {margin-left: 3.2em}
|
|
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.nolinebreak {white-space: nowrap}
|
|
span.roman {font-family: initial; font-weight: normal}
|
|
span.sansserif {font-family: sans-serif; font-weight: normal}
|
|
ul.no-bullet {list-style: none}
|
|
-->
|
|
</style>
|
|
|
|
|
|
</head>
|
|
|
|
<body lang="en">
|
|
<a name="Breakpoint_002drelated-Warnings"></a>
|
|
<div class="header">
|
|
<p>
|
|
Previous: <a href="Error-in-Breakpoints.html#Error-in-Breakpoints" accesskey="p" rel="prev">Error in Breakpoints</a>, Up: <a href="Breakpoints.html#Breakpoints" accesskey="u" rel="up">Breakpoints</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="g_t_0060_0060Breakpoint-address-adjusted_002e_002e_002e_0027_0027"></a>
|
|
<h4 class="subsection">5.1.12 “Breakpoint address adjusted...”</h4>
|
|
<a name="index-breakpoint-address-adjusted"></a>
|
|
|
|
<p>Some processor architectures place constraints on the addresses at
|
|
which breakpoints may be placed. For architectures thus constrained,
|
|
<small>GDB</small> will attempt to adjust the breakpoint’s address to comply
|
|
with the constraints dictated by the architecture.
|
|
</p>
|
|
<p>One example of such an architecture is the Fujitsu FR-V. The FR-V is
|
|
a VLIW architecture in which a number of RISC-like instructions may be
|
|
bundled together for parallel execution. The FR-V architecture
|
|
constrains the location of a breakpoint instruction within such a
|
|
bundle to the instruction with the lowest address. <small>GDB</small>
|
|
honors this constraint by adjusting a breakpoint’s address to the
|
|
first in the bundle.
|
|
</p>
|
|
<p>It is not uncommon for optimized code to have bundles which contain
|
|
instructions from different source statements, thus it may happen that
|
|
a breakpoint’s address will be adjusted from one source statement to
|
|
another. Since this adjustment may significantly alter <small>GDB</small>’s
|
|
breakpoint related behavior from what the user expects, a warning is
|
|
printed when the breakpoint is first set and also when the breakpoint
|
|
is hit.
|
|
</p>
|
|
<p>A warning like the one below is printed when setting a breakpoint
|
|
that’s been subject to address adjustment:
|
|
</p>
|
|
<div class="smallexample">
|
|
<pre class="smallexample">warning: Breakpoint address adjusted from 0x00010414 to 0x00010410.
|
|
</pre></div>
|
|
|
|
<p>Such warnings are printed both for user settable and <small>GDB</small>’s
|
|
internal breakpoints. If you see one of these warnings, you should
|
|
verify that a breakpoint set at the adjusted address will have the
|
|
desired affect. If not, the breakpoint in question may be removed and
|
|
other breakpoints may be set which will have the desired behavior.
|
|
E.g., it may be sufficient to place the breakpoint at a later
|
|
instruction. A conditional breakpoint may also be useful in some
|
|
cases to prevent the breakpoint from triggering too often.
|
|
</p>
|
|
<p><small>GDB</small> will also issue a warning when stopping at one of these
|
|
adjusted breakpoints:
|
|
</p>
|
|
<div class="smallexample">
|
|
<pre class="smallexample">warning: Breakpoint 1 address previously adjusted from 0x00010414
|
|
to 0x00010410.
|
|
</pre></div>
|
|
|
|
<p>When this warning is encountered, it may be too late to take remedial
|
|
action except in cases where the breakpoint is hit earlier or more
|
|
frequently than expected.
|
|
</p>
|
|
<hr>
|
|
<div class="header">
|
|
<p>
|
|
Previous: <a href="Error-in-Breakpoints.html#Error-in-Breakpoints" accesskey="p" rel="prev">Error in Breakpoints</a>, Up: <a href="Breakpoints.html#Breakpoints" accesskey="u" rel="up">Breakpoints</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>
|