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.
147 lines
6.3 KiB
HTML
147 lines
6.3 KiB
HTML
4 years ago
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||
|
|
<html>
|
||
|
|
<!-- Copyright (C) 1988-2018 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 "Funding Free Software", the Front-Cover
|
||
|
|
Texts being (a) (see below), and with the Back-Cover Texts being (b)
|
||
|
|
(see below). A copy of the license is included in the section entitled
|
||
|
|
"GNU Free Documentation License".
|
||
|
|
|
||
|
|
(a) The FSF's Front-Cover Text is:
|
||
|
|
|
||
|
|
A GNU Manual
|
||
|
|
|
||
|
|
(b) The FSF's Back-Cover Text is:
|
||
|
|
|
||
|
|
You have freedom to copy and modify this GNU Manual, like GNU
|
||
|
|
software. Copies published by the Free Software Foundation raise
|
||
|
|
funds for GNU development. -->
|
||
|
|
<!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ -->
|
||
|
|
<head>
|
||
|
|
<title>Debug Information (GNU Compiler Collection (GCC) Internals)</title>
|
||
|
|
|
||
|
|
<meta name="description" content="Debug Information (GNU Compiler Collection (GCC) Internals)">
|
||
|
|
<meta name="keywords" content="Debug Information (GNU Compiler Collection (GCC) Internals)">
|
||
|
|
<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="Option-Index.html#Option-Index" rel="index" title="Option Index">
|
||
|
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
||
|
|
<link href="RTL.html#RTL" rel="up" title="RTL">
|
||
|
|
<link href="Insns.html#Insns" rel="next" title="Insns">
|
||
|
|
<link href="Assembler.html#Assembler" rel="prev" title="Assembler">
|
||
|
|
<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="Debug-Information"></a>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Next: <a href="Insns.html#Insns" accesskey="n" rel="next">Insns</a>, Previous: <a href="Assembler.html#Assembler" accesskey="p" rel="prev">Assembler</a>, Up: <a href="RTL.html#RTL" accesskey="u" rel="up">RTL</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
|
||
|
|
</div>
|
||
|
|
<hr>
|
||
|
|
<a name="Variable-Location-Debug-Information-in-RTL"></a>
|
||
|
|
<h3 class="section">14.18 Variable Location Debug Information in RTL</h3>
|
||
|
|
<a name="index-Variable-Location-Debug-Information-in-RTL"></a>
|
||
|
|
|
||
|
|
<p>Variable tracking relies on <code>MEM_EXPR</code> and <code>REG_EXPR</code>
|
||
|
|
annotations to determine what user variables memory and register
|
||
|
|
references refer to.
|
||
|
|
</p>
|
||
|
|
<p>Variable tracking at assignments uses these notes only when they refer
|
||
|
|
to variables that live at fixed locations (e.g., addressable
|
||
|
|
variables, global non-automatic variables). For variables whose
|
||
|
|
location may vary, it relies on the following types of notes.
|
||
|
|
</p>
|
||
|
|
<dl compact="compact">
|
||
|
|
<dd><a name="index-var_005flocation"></a>
|
||
|
|
</dd>
|
||
|
|
<dt><code>(var_location:<var>mode</var> <var>var</var> <var>exp</var> <var>stat</var>)</code></dt>
|
||
|
|
<dd><p>Binds variable <code>var</code>, a tree, to value <var>exp</var>, an RTL
|
||
|
|
expression. It appears only in <code>NOTE_INSN_VAR_LOCATION</code> and
|
||
|
|
<code>DEBUG_INSN</code>s, with slightly different meanings. <var>mode</var>, if
|
||
|
|
present, represents the mode of <var>exp</var>, which is useful if it is a
|
||
|
|
modeless expression. <var>stat</var> is only meaningful in notes,
|
||
|
|
indicating whether the variable is known to be initialized or
|
||
|
|
uninitialized.
|
||
|
|
</p>
|
||
|
|
<a name="index-debug_005fexpr"></a>
|
||
|
|
</dd>
|
||
|
|
<dt><code>(debug_expr:<var>mode</var> <var>decl</var>)</code></dt>
|
||
|
|
<dd><p>Stands for the value bound to the <code>DEBUG_EXPR_DECL</code> <var>decl</var>,
|
||
|
|
that points back to it, within value expressions in
|
||
|
|
<code>VAR_LOCATION</code> nodes.
|
||
|
|
</p>
|
||
|
|
<a name="index-debug_005fimplicit_005fptr"></a>
|
||
|
|
</dd>
|
||
|
|
<dt><code>(debug_implicit_ptr:<var>mode</var> <var>decl</var>)</code></dt>
|
||
|
|
<dd><p>Stands for the location of a <var>decl</var> that is no longer addressable.
|
||
|
|
</p>
|
||
|
|
<a name="index-entry_005fvalue"></a>
|
||
|
|
</dd>
|
||
|
|
<dt><code>(entry_value:<var>mode</var> <var>decl</var>)</code></dt>
|
||
|
|
<dd><p>Stands for the value a <var>decl</var> had at the entry point of the
|
||
|
|
containing function.
|
||
|
|
</p>
|
||
|
|
<a name="index-debug_005fparameter_005fref"></a>
|
||
|
|
</dd>
|
||
|
|
<dt><code>(debug_parameter_ref:<var>mode</var> <var>decl</var>)</code></dt>
|
||
|
|
<dd><p>Refers to a parameter that was completely optimized out.
|
||
|
|
</p>
|
||
|
|
<a name="index-debug_005fmarker"></a>
|
||
|
|
</dd>
|
||
|
|
<dt><code>(debug_marker:<var>mode</var>)</code></dt>
|
||
|
|
<dd><p>Marks a program location. With <code>VOIDmode</code>, it stands for the
|
||
|
|
beginning of a statement, a recommended inspection point logically after
|
||
|
|
all prior side effects, and before any subsequent side effects. With
|
||
|
|
<code>BLKmode</code>, it indicates an inline entry point: the lexical block
|
||
|
|
encoded in the <code>INSN_LOCATION</code> is the enclosing block that encloses
|
||
|
|
the inlined function.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<hr>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Next: <a href="Insns.html#Insns" accesskey="n" rel="next">Insns</a>, Previous: <a href="Assembler.html#Assembler" accesskey="p" rel="prev">Assembler</a>, Up: <a href="RTL.html#RTL" accesskey="u" rel="up">RTL</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|