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.
186 lines
7.3 KiB
HTML
186 lines
7.3 KiB
HTML
<!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>Function Properties (GNU Compiler Collection (GCC) Internals)</title>
|
|
|
|
<meta name="description" content="Function Properties (GNU Compiler Collection (GCC) Internals)">
|
|
<meta name="keywords" content="Function Properties (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="Functions.html#Functions" rel="up" title="Functions">
|
|
<link href="Language_002ddependent-trees.html#Language_002ddependent-trees" rel="next" title="Language-dependent trees">
|
|
<link href="Function-Basics.html#Function-Basics" rel="prev" title="Function Basics">
|
|
<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="Function-Properties"></a>
|
|
<div class="header">
|
|
<p>
|
|
Previous: <a href="Function-Basics.html#Function-Basics" accesskey="p" rel="prev">Function Basics</a>, Up: <a href="Functions.html#Functions" accesskey="u" rel="up">Functions</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="Function-Properties-1"></a>
|
|
<h4 class="subsection">11.8.2 Function Properties</h4>
|
|
<a name="index-function-properties"></a>
|
|
<a name="index-statements"></a>
|
|
|
|
<p>To determine the scope of a function, you can use the
|
|
<code>DECL_CONTEXT</code> macro. This macro will return the class
|
|
(either a <code>RECORD_TYPE</code> or a <code>UNION_TYPE</code>) or namespace (a
|
|
<code>NAMESPACE_DECL</code>) of which the function is a member. For a virtual
|
|
function, this macro returns the class in which the function was
|
|
actually defined, not the base class in which the virtual declaration
|
|
occurred.
|
|
</p>
|
|
<p>In C, the <code>DECL_CONTEXT</code> for a function maybe another function.
|
|
This representation indicates that the GNU nested function extension
|
|
is in use. For details on the semantics of nested functions, see the
|
|
GCC Manual. The nested function can refer to local variables in its
|
|
containing function. Such references are not explicitly marked in the
|
|
tree structure; back ends must look at the <code>DECL_CONTEXT</code> for the
|
|
referenced <code>VAR_DECL</code>. If the <code>DECL_CONTEXT</code> for the
|
|
referenced <code>VAR_DECL</code> is not the same as the function currently
|
|
being processed, and neither <code>DECL_EXTERNAL</code> nor
|
|
<code>TREE_STATIC</code> hold, then the reference is to a local variable in
|
|
a containing function, and the back end must take appropriate action.
|
|
</p>
|
|
<dl compact="compact">
|
|
<dt><code>DECL_EXTERNAL</code>
|
|
<a name="index-DECL_005fEXTERNAL-1"></a>
|
|
</dt>
|
|
<dd><p>This predicate holds if the function is undefined.
|
|
</p>
|
|
</dd>
|
|
<dt><code>TREE_PUBLIC</code>
|
|
<a name="index-TREE_005fPUBLIC-1"></a>
|
|
</dt>
|
|
<dd><p>This predicate holds if the function has external linkage.
|
|
</p>
|
|
</dd>
|
|
<dt><code>TREE_STATIC</code>
|
|
<a name="index-TREE_005fSTATIC"></a>
|
|
</dt>
|
|
<dd><p>This predicate holds if the function has been defined.
|
|
</p>
|
|
</dd>
|
|
<dt><code>TREE_THIS_VOLATILE</code>
|
|
<a name="index-TREE_005fTHIS_005fVOLATILE"></a>
|
|
</dt>
|
|
<dd><p>This predicate holds if the function does not return normally.
|
|
</p>
|
|
</dd>
|
|
<dt><code>TREE_READONLY</code>
|
|
<a name="index-TREE_005fREADONLY"></a>
|
|
</dt>
|
|
<dd><p>This predicate holds if the function can only read its arguments.
|
|
</p>
|
|
</dd>
|
|
<dt><code>DECL_PURE_P</code>
|
|
<a name="index-DECL_005fPURE_005fP"></a>
|
|
</dt>
|
|
<dd><p>This predicate holds if the function can only read its arguments, but
|
|
may also read global memory.
|
|
</p>
|
|
</dd>
|
|
<dt><code>DECL_VIRTUAL_P</code>
|
|
<a name="index-DECL_005fVIRTUAL_005fP"></a>
|
|
</dt>
|
|
<dd><p>This predicate holds if the function is virtual.
|
|
</p>
|
|
</dd>
|
|
<dt><code>DECL_ARTIFICIAL</code>
|
|
<a name="index-DECL_005fARTIFICIAL-2"></a>
|
|
</dt>
|
|
<dd><p>This macro holds if the function was implicitly generated by the
|
|
compiler, rather than explicitly declared. In addition to implicitly
|
|
generated class member functions, this macro holds for the special
|
|
functions created to implement static initialization and destruction, to
|
|
compute run-time type information, and so forth.
|
|
</p>
|
|
</dd>
|
|
<dt><code>DECL_FUNCTION_SPECIFIC_TARGET</code>
|
|
<a name="index-DECL_005fFUNCTION_005fSPECIFIC_005fTARGET-1"></a>
|
|
</dt>
|
|
<dd><p>This macro returns a tree node that holds the target options that are
|
|
to be used to compile this particular function or <code>NULL_TREE</code> if
|
|
the function is to be compiled with the target options specified on
|
|
the command line.
|
|
</p>
|
|
</dd>
|
|
<dt><code>DECL_FUNCTION_SPECIFIC_OPTIMIZATION</code>
|
|
<a name="index-DECL_005fFUNCTION_005fSPECIFIC_005fOPTIMIZATION-1"></a>
|
|
</dt>
|
|
<dd><p>This macro returns a tree node that holds the optimization options
|
|
that are to be used to compile this particular function or
|
|
<code>NULL_TREE</code> if the function is to be compiled with the
|
|
optimization options specified on the command line.
|
|
</p>
|
|
</dd>
|
|
</dl>
|
|
|
|
|
|
<hr>
|
|
<div class="header">
|
|
<p>
|
|
Previous: <a href="Function-Basics.html#Function-Basics" accesskey="p" rel="prev">Function Basics</a>, Up: <a href="Functions.html#Functions" accesskey="u" rel="up">Functions</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>
|