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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/gccint/Per_002dFunction-Data.html | |
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
Change-Id: I7303388733328cd98ab9aa3c30236db67f2e9e9c
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| -rw-r--r-- | share/doc/gccint/Per_002dFunction-Data.html | 144 |
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diff --git a/share/doc/gccint/Per_002dFunction-Data.html b/share/doc/gccint/Per_002dFunction-Data.html new file mode 100644 index 0000000..8d1ccad --- /dev/null +++ b/share/doc/gccint/Per_002dFunction-Data.html @@ -0,0 +1,144 @@ +<!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 "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 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>GNU Compiler Collection (GCC) Internals: Per-Function Data</title> + +<meta name="description" content="GNU Compiler Collection (GCC) Internals: Per-Function Data"> +<meta name="keywords" content="GNU Compiler Collection (GCC) Internals: Per-Function Data"> +<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="Target-Macros.html#Target-Macros" rel="up" title="Target Macros"> +<link href="Storage-Layout.html#Storage-Layout" rel="next" title="Storage Layout"> +<link href="Run_002dtime-Target.html#Run_002dtime-Target" rel="previous" title="Run-time Target"> +<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="Per_002dFunction-Data"></a> +<div class="header"> +<p> +Next: <a href="Storage-Layout.html#Storage-Layout" accesskey="n" rel="next">Storage Layout</a>, Previous: <a href="Run_002dtime-Target.html#Run_002dtime-Target" accesskey="p" rel="previous">Run-time Target</a>, Up: <a href="Target-Macros.html#Target-Macros" accesskey="u" rel="up">Target Macros</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="Defining-data-structures-for-per_002dfunction-information_002e"></a> +<h3 class="section">18.4 Defining data structures for per-function information.</h3> +<a name="index-per_002dfunction-data"></a> +<a name="index-data-structures"></a> + +<p>If the target needs to store information on a per-function basis, GCC +provides a macro and a couple of variables to allow this. Note, just +using statics to store the information is a bad idea, since GCC supports +nested functions, so you can be halfway through encoding one function +when another one comes along. +</p> +<p>GCC defines a data structure called <code>struct function</code> which +contains all of the data specific to an individual function. This +structure contains a field called <code>machine</code> whose type is +<code>struct machine_function *</code>, which can be used by targets to point +to their own specific data. +</p> +<p>If a target needs per-function specific data it should define the type +<code>struct machine_function</code> and also the macro <code>INIT_EXPANDERS</code>. +This macro should be used to initialize the function pointer +<code>init_machine_status</code>. This pointer is explained below. +</p> +<p>One typical use of per-function, target specific data is to create an +RTX to hold the register containing the function’s return address. This +RTX can then be used to implement the <code>__builtin_return_address</code> +function, for level 0. +</p> +<p>Note—earlier implementations of GCC used a single data area to hold +all of the per-function information. Thus when processing of a nested +function began the old per-function data had to be pushed onto a +stack, and when the processing was finished, it had to be popped off the +stack. GCC used to provide function pointers called +<code>save_machine_status</code> and <code>restore_machine_status</code> to handle +the saving and restoring of the target specific information. Since the +single data area approach is no longer used, these pointers are no +longer supported. +</p> +<dl> +<dt><a name="index-INIT_005fEXPANDERS"></a>Macro: <strong>INIT_EXPANDERS</strong></dt> +<dd><p>Macro called to initialize any target specific information. This macro +is called once per function, before generation of any RTL has begun. +The intention of this macro is to allow the initialization of the +function pointer <code>init_machine_status</code>. +</p></dd></dl> + +<dl> +<dt><a name="index-init_005fmachine_005fstatus"></a>Variable: <em>void (*)(struct function *)</em> <strong>init_machine_status</strong></dt> +<dd><p>If this function pointer is non-<code>NULL</code> it will be called once per +function, before function compilation starts, in order to allow the +target to perform any target specific initialization of the +<code>struct function</code> structure. It is intended that this would be +used to initialize the <code>machine</code> of that structure. +</p> +<p><code>struct machine_function</code> structures are expected to be freed by GC. +Generally, any memory that they reference must be allocated by using +GC allocation, including the structure itself. +</p></dd></dl> + +<hr> +<div class="header"> +<p> +Next: <a href="Storage-Layout.html#Storage-Layout" accesskey="n" rel="next">Storage Layout</a>, Previous: <a href="Run_002dtime-Target.html#Run_002dtime-Target" accesskey="p" rel="previous">Run-time Target</a>, Up: <a href="Target-Macros.html#Target-Macros" accesskey="u" rel="up">Target Macros</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> |