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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/Using-RTL-SSA.html | |
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
Change-Id: I7303388733328cd98ab9aa3c30236db67f2e9e9c
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diff --git a/share/doc/gccint/Using-RTL-SSA.html b/share/doc/gccint/Using-RTL-SSA.html new file mode 100644 index 0000000..c47aee5 --- /dev/null +++ b/share/doc/gccint/Using-RTL-SSA.html @@ -0,0 +1,148 @@ +<!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: Using RTL SSA</title> + +<meta name="description" content="GNU Compiler Collection (GCC) Internals: Using RTL SSA"> +<meta name="keywords" content="GNU Compiler Collection (GCC) Internals: Using RTL SSA"> +<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-SSA.html#RTL-SSA" rel="up" title="RTL SSA"> +<link href="RTL-SSA-Instructions.html#RTL-SSA-Instructions" rel="next" title="RTL SSA Instructions"> +<link href="RTL-SSA.html#RTL-SSA" rel="previous" title="RTL SSA"> +<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-RTL-SSA"></a> +<div class="header"> +<p> +Next: <a href="RTL-SSA-Instructions.html#RTL-SSA-Instructions" accesskey="n" rel="next">RTL SSA Instructions</a>, Up: <a href="RTL-SSA.html#RTL-SSA" accesskey="u" rel="up">RTL SSA</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="Using-RTL-SSA-in-a-pass"></a> +<h4 class="subsection">14.21.1 Using RTL SSA in a pass</h4> + +<p>A pass that wants to use the RTL SSA form should start with the following: +</p> +<div class="smallexample"> +<pre class="smallexample">#define INCLUDE_ALGORITHM +#define INCLUDE_FUNCTIONAL +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "backend.h" +#include "rtl.h" +#include "df.h" +#include "rtl-ssa.h" +</pre></div> + +<p>All the RTL SSA code is contained in the <code>rtl_ssa</code> namespace, +so most passes will then want to do: +</p> +<div class="smallexample"> +<pre class="smallexample">using namespace rtl_ssa; +</pre></div> + +<p>However, this is purely a matter of taste, and the examples in the rest of +this section do not require it. +</p> +<p>The RTL SSA represention is an optional on-the-side feature that applies +on top of the normal RTL instructions. It is currently local to individual +RTL passes and is not maintained across passes. +</p> +<p>However, in order to allow the RTL SSA information to be preserved across +passes in future, ‘<samp>crtl->ssa</samp>’ points to the current function’s +SSA form (if any). Passes that want to use the RTL SSA form should +first do: +</p> +<div class="smallexample"> +<pre class="smallexample">crtl->ssa = new rtl_ssa::function_info (<var>fn</var>); +</pre></div> + +<p>where <var>fn</var> is the function that the pass is processing. +(Passes that are <code>using namespace rtl_ssa</code> do not need +the ‘<samp>rtl_ssa::</samp>’.) +</p> +<p>Once the pass has finished with the SSA form, it should do the following: +</p> +<div class="smallexample"> +<pre class="smallexample">free_dominance_info (CDI_DOMINATORS); +if (crtl->ssa->perform_pending_updates ()) + cleanup_cfg (0); + +delete crtl->ssa; +crtl->ssa = nullptr; +</pre></div> + +<p>The <code>free_dominance_info</code> call is necessary because +dominance information is not currently maintained between RTL passes. +The next two lines commit any changes to the RTL instructions that +were queued for later; see the comment above the declaration of +<code>perform_pending_updates</code> for details. The final two lines +discard the RTL SSA form and free the associated memory. +</p> +<hr> +<div class="header"> +<p> +Next: <a href="RTL-SSA-Instructions.html#RTL-SSA-Instructions" accesskey="n" rel="next">RTL SSA Instructions</a>, Up: <a href="RTL-SSA.html#RTL-SSA" accesskey="u" rel="up">RTL SSA</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> |