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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/Basic-Statements.html | |
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
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diff --git a/share/doc/gccint/Basic-Statements.html b/share/doc/gccint/Basic-Statements.html new file mode 100644 index 0000000..904c8da --- /dev/null +++ b/share/doc/gccint/Basic-Statements.html @@ -0,0 +1,217 @@ +<!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: Basic Statements</title> + +<meta name="description" content="GNU Compiler Collection (GCC) Internals: Basic Statements"> +<meta name="keywords" content="GNU Compiler Collection (GCC) Internals: Basic Statements"> +<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="Statements.html#Statements" rel="up" title="Statements"> +<link href="Blocks.html#Blocks" rel="next" title="Blocks"> +<link href="Statements.html#Statements" rel="previous" title="Statements"> +<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="Basic-Statements"></a> +<div class="header"> +<p> +Next: <a href="Blocks.html#Blocks" accesskey="n" rel="next">Blocks</a>, Up: <a href="Statements.html#Statements" accesskey="u" rel="up">Statements</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="Basic-Statements-1"></a> +<h4 class="subsection">11.7.1 Basic Statements</h4> +<a name="index-Basic-Statements"></a> + +<dl compact="compact"> +<dt><code>ASM_EXPR</code></dt> +<dd> +<p>Used to represent an inline assembly statement. For an inline assembly +statement like: +</p><div class="smallexample"> +<pre class="smallexample">asm ("mov x, y"); +</pre></div> +<p>The <code>ASM_STRING</code> macro will return a <code>STRING_CST</code> node for +<code>"mov x, y"</code>. If the original statement made use of the +extended-assembly syntax, then <code>ASM_OUTPUTS</code>, +<code>ASM_INPUTS</code>, and <code>ASM_CLOBBERS</code> will be the outputs, inputs, +and clobbers for the statement, represented as <code>STRING_CST</code> nodes. +The extended-assembly syntax looks like: +</p><div class="smallexample"> +<pre class="smallexample">asm ("fsinx %1,%0" : "=f" (result) : "f" (angle)); +</pre></div> +<p>The first string is the <code>ASM_STRING</code>, containing the instruction +template. The next two strings are the output and inputs, respectively; +this statement has no clobbers. As this example indicates, “plain” +assembly statements are merely a special case of extended assembly +statements; they have no cv-qualifiers, outputs, inputs, or clobbers. +All of the strings will be <code>NUL</code>-terminated, and will contain no +embedded <code>NUL</code>-characters. +</p> +<p>If the assembly statement is declared <code>volatile</code>, or if the +statement was not an extended assembly statement, and is therefore +implicitly volatile, then the predicate <code>ASM_VOLATILE_P</code> will hold +of the <code>ASM_EXPR</code>. +</p> +</dd> +<dt><code>DECL_EXPR</code></dt> +<dd> +<p>Used to represent a local declaration. The <code>DECL_EXPR_DECL</code> macro +can be used to obtain the entity declared. This declaration may be a +<code>LABEL_DECL</code>, indicating that the label declared is a local label. +(As an extension, GCC allows the declaration of labels with scope.) In +C, this declaration may be a <code>FUNCTION_DECL</code>, indicating the +use of the GCC nested function extension. For more information, +see <a href="Functions.html#Functions">Functions</a>. +</p> +</dd> +<dt><code>LABEL_EXPR</code></dt> +<dd> +<p>Used to represent a label. The <code>LABEL_DECL</code> declared by this +statement can be obtained with the <code>LABEL_EXPR_LABEL</code> macro. The +<code>IDENTIFIER_NODE</code> giving the name of the label can be obtained from +the <code>LABEL_DECL</code> with <code>DECL_NAME</code>. +</p> +</dd> +<dt><code>GOTO_EXPR</code></dt> +<dd> +<p>Used to represent a <code>goto</code> statement. The <code>GOTO_DESTINATION</code> will +usually be a <code>LABEL_DECL</code>. However, if the “computed goto” extension +has been used, the <code>GOTO_DESTINATION</code> will be an arbitrary expression +indicating the destination. This expression will always have pointer type. +</p> +</dd> +<dt><code>RETURN_EXPR</code></dt> +<dd> +<p>Used to represent a <code>return</code> statement. Operand 0 represents the +value to return. It should either be the <code>RESULT_DECL</code> for the +containing function, or a <code>MODIFY_EXPR</code> or <code>INIT_EXPR</code> +setting the function’s <code>RESULT_DECL</code>. It will be +<code>NULL_TREE</code> if the statement was just +</p><div class="smallexample"> +<pre class="smallexample">return; +</pre></div> + +</dd> +<dt><code>LOOP_EXPR</code></dt> +<dd><p>These nodes represent “infinite” loops. The <code>LOOP_EXPR_BODY</code> +represents the body of the loop. It should be executed forever, unless +an <code>EXIT_EXPR</code> is encountered. +</p> +</dd> +<dt><code>EXIT_EXPR</code></dt> +<dd><p>These nodes represent conditional exits from the nearest enclosing +<code>LOOP_EXPR</code>. The single operand is the condition; if it is +nonzero, then the loop should be exited. An <code>EXIT_EXPR</code> will only +appear within a <code>LOOP_EXPR</code>. +</p> +</dd> +<dt><code>SWITCH_EXPR</code></dt> +<dd> +<p>Used to represent a <code>switch</code> statement. The <code>SWITCH_COND</code> +is the expression on which the switch is occurring. The +<code>SWITCH_BODY</code> is the body of the switch statement. +<code>SWITCH_ALL_CASES_P</code> is true if the switch includes a default +label or the case label ranges cover all possible values of the +condition expression. +</p> +<p>Note that <code>TREE_TYPE</code> for a <code>SWITCH_EXPR</code> represents the +original type of switch expression as given in the source, before any +compiler conversions, instead of the type of the switch expression +itself (which is not meaningful). +</p> +</dd> +<dt><code>CASE_LABEL_EXPR</code></dt> +<dd> +<p>Use to represent a <code>case</code> label, range of <code>case</code> labels, or a +<code>default</code> label. If <code>CASE_LOW</code> is <code>NULL_TREE</code>, then this is a +<code>default</code> label. Otherwise, if <code>CASE_HIGH</code> is <code>NULL_TREE</code>, then +this is an ordinary <code>case</code> label. In this case, <code>CASE_LOW</code> is +an expression giving the value of the label. Both <code>CASE_LOW</code> and +<code>CASE_HIGH</code> are <code>INTEGER_CST</code> nodes. These values will have +the same type as the condition expression in the switch statement. +</p> +<p>Otherwise, if both <code>CASE_LOW</code> and <code>CASE_HIGH</code> are defined, the +statement is a range of case labels. Such statements originate with the +extension that allows users to write things of the form: +</p><div class="smallexample"> +<pre class="smallexample">case 2 ... 5: +</pre></div> +<p>The first value will be <code>CASE_LOW</code>, while the second will be +<code>CASE_HIGH</code>. +</p> +</dd> +<dt><code>DEBUG_BEGIN_STMT</code></dt> +<dd> +<p>Marks the beginning of a source statement, for purposes of debug +information generation. +</p> +</dd> +</dl> + + +<hr> +<div class="header"> +<p> +Next: <a href="Blocks.html#Blocks" accesskey="n" rel="next">Blocks</a>, Up: <a href="Statements.html#Statements" accesskey="u" rel="up">Statements</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> |