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149 lines
9.1 KiB
HTML
149 lines
9.1 KiB
HTML
4 years ago
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<!-- Copyright (C) 1988-2018 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3 or
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any later version published by the Free Software Foundation; with the
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Invariant Sections being "Funding Free Software", the Front-Cover
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Texts being (a) (see below), and with the Back-Cover Texts being (b)
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(see below). A copy of the license is included in the section entitled
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"GNU Free Documentation License".
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(a) The FSF's Front-Cover Text is:
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A GNU Manual
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(b) The FSF's Back-Cover Text is:
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You have freedom to copy and modify this GNU Manual, like GNU
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software. Copies published by the Free Software Foundation raise
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funds for GNU development. -->
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<!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ -->
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<head>
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<title>RTL (GNU Compiler Collection (GCC) Internals)</title>
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<meta name="description" content="RTL (GNU Compiler Collection (GCC) Internals)">
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<meta name="keywords" content="RTL (GNU Compiler Collection (GCC) Internals)">
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<meta name="resource-type" content="document">
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<meta name="distribution" content="global">
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<meta name="Generator" content="makeinfo">
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<link href="index.html#Top" rel="start" title="Top">
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<link href="Option-Index.html#Option-Index" rel="index" title="Option Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="index.html#Top" rel="up" title="Top">
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<link href="RTL-Objects.html#RTL-Objects" rel="next" title="RTL Objects">
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<link href="Memory-model.html#Memory-model" rel="prev" title="Memory model">
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<style type="text/css">
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</style>
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</head>
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<body lang="en">
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<a name="RTL"></a>
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<div class="header">
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<p>
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Next: <a href="Control-Flow.html#Control-Flow" accesskey="n" rel="next">Control Flow</a>, Previous: <a href="Tree-SSA.html#Tree-SSA" accesskey="p" rel="prev">Tree SSA</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</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>
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</div>
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<hr>
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<a name="RTL-Representation"></a>
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<h2 class="chapter">14 RTL Representation</h2>
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<a name="index-RTL-representation"></a>
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<a name="index-representation-of-RTL"></a>
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<a name="index-Register-Transfer-Language-_0028RTL_0029"></a>
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<p>The last part of the compiler work is done on a low-level intermediate
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representation called Register Transfer Language. In this language, the
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instructions to be output are described, pretty much one by one, in an
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algebraic form that describes what the instruction does.
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</p>
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<p>RTL is inspired by Lisp lists. It has both an internal form, made up of
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structures that point at other structures, and a textual form that is used
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in the machine description and in printed debugging dumps. The textual
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form uses nested parentheses to indicate the pointers in the internal form.
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</p>
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<table class="menu" border="0" cellspacing="0">
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<tr><td align="left" valign="top">• <a href="RTL-Objects.html#RTL-Objects" accesskey="1">RTL Objects</a>:</td><td> </td><td align="left" valign="top">Expressions vs vectors vs strings vs integers.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="RTL-Classes.html#RTL-Classes" accesskey="2">RTL Classes</a>:</td><td> </td><td align="left" valign="top">Categories of RTL expression objects, and their structure.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Accessors.html#Accessors" accesskey="3">Accessors</a>:</td><td> </td><td align="left" valign="top">Macros to access expression operands or vector elts.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Special-Accessors.html#Special-Accessors" accesskey="4">Special Accessors</a>:</td><td> </td><td align="left" valign="top">Macros to access specific annotations on RTL.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Flags.html#Flags" accesskey="5">Flags</a>:</td><td> </td><td align="left" valign="top">Other flags in an RTL expression.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Machine-Modes.html#Machine-Modes" accesskey="6">Machine Modes</a>:</td><td> </td><td align="left" valign="top">Describing the size and format of a datum.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Constants.html#Constants" accesskey="7">Constants</a>:</td><td> </td><td align="left" valign="top">Expressions with constant values.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Regs-and-Memory.html#Regs-and-Memory" accesskey="8">Regs and Memory</a>:</td><td> </td><td align="left" valign="top">Expressions representing register contents or memory.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Arithmetic.html#Arithmetic" accesskey="9">Arithmetic</a>:</td><td> </td><td align="left" valign="top">Expressions representing arithmetic on other expressions.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Comparisons.html#Comparisons">Comparisons</a>:</td><td> </td><td align="left" valign="top">Expressions representing comparison of expressions.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Bit_002dFields.html#Bit_002dFields">Bit-Fields</a>:</td><td> </td><td align="left" valign="top">Expressions representing bit-fields in memory or reg.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Vector-Operations.html#Vector-Operations">Vector Operations</a>:</td><td> </td><td align="left" valign="top">Expressions involving vector datatypes.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Conversions.html#Conversions">Conversions</a>:</td><td> </td><td align="left" valign="top">Extending, truncating, floating or fixing.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="RTL-Declarations.html#RTL-Declarations">RTL Declarations</a>:</td><td> </td><td align="left" valign="top">Declaring volatility, constancy, etc.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Side-Effects.html#Side-Effects">Side Effects</a>:</td><td> </td><td align="left" valign="top">Expressions for storing in registers, etc.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Incdec.html#Incdec">Incdec</a>:</td><td> </td><td align="left" valign="top">Embedded side-effects for autoincrement addressing.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Assembler.html#Assembler">Assembler</a>:</td><td> </td><td align="left" valign="top">Representing <code>asm</code> with operands.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Debug-Information.html#Debug-Information">Debug Information</a>:</td><td> </td><td align="left" valign="top">Expressions representing debugging information.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Insns.html#Insns">Insns</a>:</td><td> </td><td align="left" valign="top">Expression types for entire insns.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Calls.html#Calls">Calls</a>:</td><td> </td><td align="left" valign="top">RTL representation of function call insns.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Sharing.html#Sharing">Sharing</a>:</td><td> </td><td align="left" valign="top">Some expressions are unique; others *must* be copied.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Reading-RTL.html#Reading-RTL">Reading RTL</a>:</td><td> </td><td align="left" valign="top">Reading textual RTL from a file.
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</td></tr>
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</table>
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<hr>
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<div class="header">
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<p>
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Next: <a href="Control-Flow.html#Control-Flow" accesskey="n" rel="next">Control Flow</a>, Previous: <a href="Tree-SSA.html#Tree-SSA" accesskey="p" rel="prev">Tree SSA</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</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>
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</div>
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</body>
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</html>
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