Gitiles
Code Review Sign In
gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / ad405ce3d2cfb389d3dbf7d22da6b693f7eaa06a / . / docs / LangRef.html
blob: 2c94793c83b7cbd2da0baadf0a432fd59bab1f52 [file] [log] [blame]
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3<html>
4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]20 <li><a href="#typesystem">Type System</a>
21 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]22 <li><a href="#t_primitive">Primitive Types</a>
23 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]24 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]25 </ol>
26 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]27 <li><a href="#t_derived">Derived Types</a>
28 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]29 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]30 <li><a href="#t_function">Function Type</a></li>
31 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]32 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]33 <li><a href="#t_packed">Packed Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]34 </ol>
35 </li>
36 </ol>
37 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]38 <li><a href="#highlevel">High Level Structure</a>
39 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]40 <li><a href="#modulestructure">Module Structure</a></li>
41 <li><a href="#globalvars">Global Variables</a></li>
42 <li><a href="#functionstructure">Function Structure</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]43 </ol>
44 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]45 <li><a href="#instref">Instruction Reference</a>
46 <ol>
47 <li><a href="#terminators">Terminator Instructions</a>
48 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]49 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
50 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]51 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
52 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]53 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
54 </ol>
55 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]56 <li><a href="#binaryops">Binary Operations</a>
57 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]58 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
59 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
60 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
61 <li><a href="#i_div">'<tt>div</tt>' Instruction</a></li>
62 <li><a href="#i_rem">'<tt>rem</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]63 <li><a href="#i_setcc">'<tt>set<i>cc</i></tt>' Instructions</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]64 </ol>
65 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]66 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
67 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]68 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]69 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]70 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
71 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
72 <li><a href="#i_shr">'<tt>shr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]73 </ol>
74 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]75 <li><a href="#memoryops">Memory Access Operations</a>
76 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]77 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
78 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
79 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
80 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
81 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
82 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
83 </ol>
84 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]85 <li><a href="#otherops">Other Operations</a>
86 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]87 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]88 <li><a href="#i_cast">'<tt>cast .. to</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]89 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]90 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]91 <li><a href="#i_vanext">'<tt>vanext</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]92 <li><a href="#i_vaarg">'<tt>vaarg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]93 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]94 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]95 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]96 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]97 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]98 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]99 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
100 <ol>
101 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
102 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
103 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
104 </ol>
105 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]106 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
107 <ol>
108 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
109 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
110 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
111 </ol>
112 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]113 <li><a href="#int_codegen">Code Generator Intrinsics</a>
114 <ol>
115 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
116 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]117 </ol>
118 </li>
119 <li><a href="#int_os">Operating System Intrinsics</a>
120 <ol>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]121 <li><a href="#i_readport">'<tt>llvm.readport</tt>' Intrinsic</a></li>
122 <li><a href="#i_writeport">'<tt>llvm.writeport</tt>' Intrinsic</a></li>
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]123 <li><a href="#i_readio">'<tt>llvm.readio</tt>' Intrinsic</a></li>
124 <li><a href="#i_writeio">'<tt>llvm.writeio</tt>' Intrinsic</a></li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]125 </ol>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]126 <li><a href="#int_libc">Standard C Library Intrinsics</a>
127 <ol>
128 <li><a href="#i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a></li>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]129 <li><a href="#i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a></li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]130 <li><a href="#i_memset">'<tt>llvm.memset</tt>' Intrinsic</a></li>
Alkis Evlogimenos96853722004-06-12 19:19:14 +0000[diff] [blame]131 <li><a href="#i_isunordered">'<tt>llvm.isunordered</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]132 </ol>
133 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]134 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]135 </ol>
136 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]137</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]138
139<div class="doc_author">
140 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
141 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]142</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]143
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]144<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]145<div class="doc_section"> <a name="abstract">Abstract </a></div>
146<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]147
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]148<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]149<p>This document is a reference manual for the LLVM assembly language.
150LLVM is an SSA based representation that provides type safety,
151low-level operations, flexibility, and the capability of representing
152'all' high-level languages cleanly. It is the common code
153representation used throughout all phases of the LLVM compilation
154strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]155</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]156
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]157<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]158<div class="doc_section"> <a name="introduction">Introduction</a> </div>
159<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]160
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]161<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]162
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]163<p>The LLVM code representation is designed to be used in three
164different forms: as an in-memory compiler IR, as an on-disk bytecode
165representation (suitable for fast loading by a Just-In-Time compiler),
166and as a human readable assembly language representation. This allows
167LLVM to provide a powerful intermediate representation for efficient
168compiler transformations and analysis, while providing a natural means
169to debug and visualize the transformations. The three different forms
170of LLVM are all equivalent. This document describes the human readable
171representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]172
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]173<p>The LLVM representation aims to be a light-weight and low-level
174while being expressive, typed, and extensible at the same time. It
175aims to be a "universal IR" of sorts, by being at a low enough level
176that high-level ideas may be cleanly mapped to it (similar to how
177microprocessors are "universal IR's", allowing many source languages to
178be mapped to them). By providing type information, LLVM can be used as
179the target of optimizations: for example, through pointer analysis, it
180can be proven that a C automatic variable is never accessed outside of
181the current function... allowing it to be promoted to a simple SSA
182value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]183
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]184</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]185
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]186<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]187<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]188
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]189<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]190
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]191<p>It is important to note that this document describes 'well formed'
192LLVM assembly language. There is a difference between what the parser
193accepts and what is considered 'well formed'. For example, the
194following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]195
196<pre>
197 %x = <a href="#i_add">add</a> int 1, %x
198</pre>
199
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]200<p>...because the definition of <tt>%x</tt> does not dominate all of
201its uses. The LLVM infrastructure provides a verification pass that may
202be used to verify that an LLVM module is well formed. This pass is
203automatically run by the parser after parsing input assembly, and by
204the optimizer before it outputs bytecode. The violations pointed out
205by the verifier pass indicate bugs in transformation passes or input to
206the parser.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]207
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]208<!-- Describe the typesetting conventions here. --> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]209
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]210<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]211<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]212<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]213
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]214<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]215
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]216<p>LLVM uses three different forms of identifiers, for different
217purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]218
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]219<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]220 <li>Numeric constants are represented as you would expect: 12, -3
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]221123.421, etc. Floating point constants have an optional hexadecimal
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]222notation.</li>
223 <li>Named values are represented as a string of characters with a '%'
224prefix. For example, %foo, %DivisionByZero,
225%a.really.long.identifier. The actual regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
226Identifiers which require other characters in their names can be
227surrounded with quotes. In this way, anything except a <tt>"</tt>
228character can be used in a name.</li>
229 <li>Unnamed values are represented as an unsigned numeric value with
230a '%' prefix. For example, %12, %2, %44.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]231</ol>
John Criswell6794d922004-03-12 21:19:06 +0000[diff] [blame]232<p>LLVM requires that values start with a '%' sign for two reasons:
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]233Compilers don't need to worry about name clashes with reserved words,
234and the set of reserved words may be expanded in the future without
235penalty. Additionally, unnamed identifiers allow a compiler to quickly
236come up with a temporary variable without having to avoid symbol table
237conflicts.</p>
238<p>Reserved words in LLVM are very similar to reserved words in other
239languages. There are keywords for different opcodes ('<tt><a
240 href="#i_add">add</a></tt>', '<tt><a href="#i_cast">cast</a></tt>', '<tt><a
241 href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
242 href="#t_void">void</a></tt>', '<tt><a href="#t_uint">uint</a></tt>',
243etc...), and others. These reserved words cannot conflict with
244variable names, because none of them start with a '%' character.</p>
245<p>Here is an example of LLVM code to multiply the integer variable '<tt>%X</tt>'
246by 8:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]247<p>The easy way:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]248<pre> %result = <a href="#i_mul">mul</a> uint %X, 8<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]249<p>After strength reduction:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]250<pre> %result = <a href="#i_shl">shl</a> uint %X, ubyte 3<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]251<p>And the hard way:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]252<pre> <a href="#i_add">add</a> uint %X, %X <i>; yields {uint}:%0</i>
253 <a
254 href="#i_add">add</a> uint %0, %0 <i>; yields {uint}:%1</i>
255 %result = <a
256 href="#i_add">add</a> uint %1, %1<br></pre>
257<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
258important lexical features of LLVM:</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]259<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]260 <li>Comments are delimited with a '<tt>;</tt>' and go until the end
261of line.</li>
262 <li>Unnamed temporaries are created when the result of a computation
263is not assigned to a named value.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]264 <li>Unnamed temporaries are numbered sequentially</li>
265</ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]266<p>...and it also show a convention that we follow in this document.
267When demonstrating instructions, we will follow an instruction with a
268comment that defines the type and name of value produced. Comments are
269shown in italic text.</p>
270<p>The one non-intuitive notation for constants is the optional
271hexidecimal form of floating point constants. For example, the form '<tt>double
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2720x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2734.5e+15</tt>' which is also supported by the parser. The only time
274hexadecimal floating point constants are useful (and the only time that
275they are generated by the disassembler) is when an FP constant has to
276be emitted that is not representable as a decimal floating point number
277exactly. For example, NaN's, infinities, and other special cases are
278represented in their IEEE hexadecimal format so that assembly and
279disassembly do not cause any bits to change in the constants.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]280</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]281<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]282<div class="doc_section"> <a name="typesystem">Type System</a> </div>
283<!-- *********************************************************************** -->
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]284<div class="doc_text">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]285<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]286intermediate representation. Being typed enables a number of
287optimizations to be performed on the IR directly, without having to do
288extra analyses on the side before the transformation. A strong type
289system makes it easier to read the generated code and enables novel
290analyses and transformations that are not feasible to perform on normal
291three address code representations.</p>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame]292<!-- The written form for the type system was heavily influenced by the
293syntactic problems with types in the C language<sup><a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]294href="#rw_stroustrup">1</a></sup>.<p> --> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]295<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]296<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]297<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]298<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]299system. The current set of primitive types are as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]300
301<table border="0" style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]302 <tbody>
303 <tr>
304 <td>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]305 <table border="1" cellspacing="0" cellpadding="4" style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]306 <tbody>
307 <tr>
308 <td><tt>void</tt></td>
309 <td>No value</td>
310 </tr>
311 <tr>
312 <td><tt>ubyte</tt></td>
313 <td>Unsigned 8 bit value</td>
314 </tr>
315 <tr>
316 <td><tt>ushort</tt></td>
317 <td>Unsigned 16 bit value</td>
318 </tr>
319 <tr>
320 <td><tt>uint</tt></td>
321 <td>Unsigned 32 bit value</td>
322 </tr>
323 <tr>
324 <td><tt>ulong</tt></td>
325 <td>Unsigned 64 bit value</td>
326 </tr>
327 <tr>
328 <td><tt>float</tt></td>
329 <td>32 bit floating point value</td>
330 </tr>
331 <tr>
332 <td><tt>label</tt></td>
333 <td>Branch destination</td>
334 </tr>
335 </tbody>
336 </table>
337 </td>
338 <td valign="top">
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]339 <table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]340 <tbody>
341 <tr>
342 <td><tt>bool</tt></td>
343 <td>True or False value</td>
344 </tr>
345 <tr>
346 <td><tt>sbyte</tt></td>
347 <td>Signed 8 bit value</td>
348 </tr>
349 <tr>
350 <td><tt>short</tt></td>
351 <td>Signed 16 bit value</td>
352 </tr>
353 <tr>
354 <td><tt>int</tt></td>
355 <td>Signed 32 bit value</td>
356 </tr>
357 <tr>
358 <td><tt>long</tt></td>
359 <td>Signed 64 bit value</td>
360 </tr>
361 <tr>
362 <td><tt>double</tt></td>
363 <td>64 bit floating point value</td>
364 </tr>
365 </tbody>
366 </table>
367 </td>
368 </tr>
369 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]370</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]371
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]372</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]373<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]374<div class="doc_subsubsection"> <a name="t_classifications">Type
375Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]376<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]377<p>These different primitive types fall into a few useful
378classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]379
380<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]381 <tbody>
382 <tr>
383 <td><a name="t_signed">signed</a></td>
384 <td><tt>sbyte, short, int, long, float, double</tt></td>
385 </tr>
386 <tr>
387 <td><a name="t_unsigned">unsigned</a></td>
388 <td><tt>ubyte, ushort, uint, ulong</tt></td>
389 </tr>
390 <tr>
391 <td><a name="t_integer">integer</a></td>
392 <td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td>
393 </tr>
394 <tr>
395 <td><a name="t_integral">integral</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]396 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long</tt>
397 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]398 </tr>
399 <tr>
400 <td><a name="t_floating">floating point</a></td>
401 <td><tt>float, double</tt></td>
402 </tr>
403 <tr>
404 <td><a name="t_firstclass">first class</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]405 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long,<br>
406 float, double, <a href="#t_pointer">pointer</a>,
407 <a href="#t_packed">packed</a></tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]408 </tr>
409 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]410</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]411
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]412<p>The <a href="#t_firstclass">first class</a> types are perhaps the
413most important. Values of these types are the only ones which can be
414produced by instructions, passed as arguments, or used as operands to
415instructions. This means that all structures and arrays must be
416manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]417</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]418<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]419<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]420<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]421<p>The real power in LLVM comes from the derived types in the system.
422This is what allows a programmer to represent arrays, functions,
423pointers, and other useful types. Note that these derived types may be
424recursive: For example, it is possible to have a two dimensional array.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]425</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]426<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]427<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]428<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]429<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]430<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]431sequentially in memory. The array type requires a size (number of
432elements) and an underlying data type.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]433<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]434<pre> [&lt;# elements&gt; x &lt;elementtype&gt;]<br></pre>
435<p>The number of elements is a constant integer value, elementtype may
436be any type with a size.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]437<h5>Examples:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]438<p> <tt>[40 x int ]</tt>: Array of 40 integer values.<br>
439<tt>[41 x int ]</tt>: Array of 41 integer values.<br>
440<tt>[40 x uint]</tt>: Array of 40 unsigned integer values.</p>
441<p> </p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]442<p>Here are some examples of multidimensional arrays:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]443
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]444<table border="0" cellpadding="0" cellspacing="0">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]445 <tbody>
446 <tr>
447 <td><tt>[3 x [4 x int]]</tt></td>
448 <td>: 3x4 array integer values.</td>
449 </tr>
450 <tr>
451 <td><tt>[12 x [10 x float]]</tt></td>
452 <td>: 12x10 array of single precision floating point values.</td>
453 </tr>
454 <tr>
455 <td><tt>[2 x [3 x [4 x uint]]]</tt></td>
456 <td>: 2x3x4 array of unsigned integer values.</td>
457 </tr>
458 </tbody>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]459</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]460
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]461</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]462<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]463<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]464<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]465<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]466<p>The function type can be thought of as a function signature. It
467consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]468Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]469(which are structures of pointers to functions), for indirect function
470calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]471<p>
472The return type of a function type cannot be an aggregate type.
473</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]474<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]475<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]476<p>Where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
477specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]478which indicates that the function takes a variable number of arguments.
479Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]480 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]481<h5>Examples:</h5>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]482
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]483<table border="0" cellpadding="0" cellspacing="0">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]484 <tbody>
485 <tr>
486 <td><tt>int (int)</tt></td>
487 <td>: function taking an <tt>int</tt>, returning an <tt>int</tt></td>
488 </tr>
489 <tr>
490 <td><tt>float (int, int *) *</tt></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]491 <td>: <a href="#t_pointer">Pointer</a> to a function that takes an
492 <tt>int</tt> and a <a href="#t_pointer">pointer</a> to <tt>int</tt>,
493 returning <tt>float</tt>.</td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]494 </tr>
495 <tr>
496 <td><tt>int (sbyte *, ...)</tt></td>
497 <td>: A vararg function that takes at least one <a
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]498 href="#t_pointer">pointer</a> to <tt>sbyte</tt> (signed char in C), which
499 returns an integer. This is the signature for <tt>printf</tt> in
500 LLVM.</td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]501 </tr>
502 </tbody>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]503</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]504
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]505</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]506<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]507<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]508<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]509<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]510<p>The structure type is used to represent a collection of data members
511together in memory. The packing of the field types is defined to match
512the ABI of the underlying processor. The elements of a structure may
513be any type that has a size.</p>
514<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
515and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
516field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
517instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]518<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]519<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]520<h5>Examples:</h5>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]521
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]522<table border="0" cellpadding="0" cellspacing="0">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]523 <tbody>
524 <tr>
525 <td><tt>{ int, int, int }</tt></td>
526 <td>: a triple of three <tt>int</tt> values</td>
527 </tr>
528 <tr>
529 <td><tt>{ float, int (int) * }</tt></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]530 <td>: A pair, where the first element is a <tt>float</tt> and the second
531 element is a <a href="#t_pointer">pointer</a> to a <a
532 href="#t_function">function</a> that takes an <tt>int</tt>, returning an
533 <tt>int</tt>.</td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]534 </tr>
535 </tbody>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]536</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]537
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]538</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]539<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]540<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]541<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]542<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]543<p>As in many languages, the pointer type represents a pointer or
544reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]545<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]546<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]547<h5>Examples:</h5>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]548
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]549<table border="0" cellpadding="0" cellspacing="0">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]550 <tbody>
551 <tr>
552 <td><tt>[4x int]*</tt></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]553 <td>: <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
554 four <tt>int</tt> values</td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]555 </tr>
556 <tr>
557 <td><tt>int (int *) *</tt></td>
558 <td>: A <a href="#t_pointer">pointer</a> to a <a
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]559 href="#t_function">function</a> that takes an <tt>int</tt>, returning an
560 <tt>int</tt>.</td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]561 </tr>
562 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]563</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]564</div>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]565<!-- _______________________________________________________________________ -->
566<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]567<div class="doc_text">
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]568<h5>Overview:</h5>
569<p>A packed type is a simple derived type that represents a vector
570of elements. Packed types are used when multiple primitive data
571are operated in parallel using a single instruction (SIMD).
572A packed type requires a size (number of
573elements) and an underlying primitive data type. Packed types are
574considered <a href="#t_firstclass">first class</a>.</p>
575<h5>Syntax:</h5>
576<pre> &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;<br></pre>
577<p>The number of elements is a constant integer value, elementtype may
578be any integral or floating point type.</p>
579<h5>Examples:</h5>
580<p> <tt>&lt;4 x int&gt;</tt>: Packed vector of 4 integer values.<br>
581<tt>&lt;8 x float&gt;</tt>: Packed vector of 8 floating-point values.<br>
582<tt>&lt;2 x uint&gt;</tt>: Packed vector of 2 unsigned integer values.</p>
583<p> </p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]584</div>
585
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]586<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]587<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]588<!-- *********************************************************************** -->
589<!-- ======================================================================= -->
590<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
591</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]592<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]593<p>LLVM programs are composed of "Module"s, each of which is a
594translation unit of the input programs. Each module consists of
595functions, global variables, and symbol table entries. Modules may be
596combined together with the LLVM linker, which merges function (and
597global variable) definitions, resolves forward declarations, and merges
598symbol table entries. Here is an example of the "hello world" module:</p>
599<pre><i>; Declare the string constant as a global constant...</i>
600<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
601 href="#globalvars">constant</a> <a href="#t_array">[13 x sbyte]</a> c"hello world\0A\00" <i>; [13 x sbyte]*</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]602
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]603<i>; External declaration of the puts function</i>
604<a href="#functionstructure">declare</a> int %puts(sbyte*) <i>; int(sbyte*)* </i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]605
606<i>; Definition of main function</i>
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]607int %main() { <i>; int()* </i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]608 <i>; Convert [13x sbyte]* to sbyte *...</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]609 %cast210 = <a
610 href="#i_getelementptr">getelementptr</a> [13 x sbyte]* %.LC0, long 0, long 0 <i>; sbyte*</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]611
612 <i>; Call puts function to write out the string to stdout...</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]613 <a
614 href="#i_call">call</a> int %puts(sbyte* %cast210) <i>; int</i>
615 <a
616 href="#i_ret">ret</a> int 0<br>}<br></pre>
617<p>This example is made up of a <a href="#globalvars">global variable</a>
618named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
619function, and a <a href="#functionstructure">function definition</a>
620for "<tt>main</tt>".</p>
621<a name="linkage"> In general, a module is made up of a list of global
622values, where both functions and global variables are global values.
623Global values are represented by a pointer to a memory location (in
624this case, a pointer to an array of char, and a pointer to a function),
625and have one of the following linkage types:</a>
626<p> </p>
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]627<dl>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]629 <dd>Global values with internal linkage are only directly accessible
630by objects in the current module. In particular, linking code into a
631module with an internal global value may cause the internal to be
632renamed as necessary to avoid collisions. Because the symbol is
633internal to the module, all references can be updated. This
634corresponds to the notion of the '<tt>static</tt>' keyword in C, or the
635idea of "anonymous namespaces" in C++.
636 <p> </p>
637 </dd>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]639 <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt>
640linkage, with the twist that linking together two modules defining the
641same <tt>linkonce</tt> globals will cause one of the globals to be
642discarded. This is typically used to implement inline functions.
643Unreferenced <tt>linkonce</tt> globals are allowed to be discarded.
644 <p> </p>
645 </dd>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]646 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]647 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt>
648linkage, except that unreferenced <tt>weak</tt> globals may not be
649discarded. This is used to implement constructs in C such as "<tt>int
650X;</tt>" at global scope.
651 <p> </p>
652 </dd>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]653 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]654 <dd>"<tt>appending</tt>" linkage may only be applied to global
655variables of pointer to array type. When two global variables with
656appending linkage are linked together, the two global arrays are
657appended together. This is the LLVM, typesafe, equivalent of having
658the system linker append together "sections" with identical names when
659.o files are linked.
660 <p> </p>
661 </dd>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]662 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]663 <dd>If none of the above identifiers are used, the global is
664externally visible, meaning that it participates in linkage and can be
665used to resolve external symbol references.
666 <p> </p>
667 </dd>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]668</dl>
669<p> </p>
670<p><a name="linkage_external">For example, since the "<tt>.LC0</tt>"
671variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
672variable and was linked with this one, one of the two would be renamed,
673preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
674external (i.e., lacking any linkage declarations), they are accessible
675outside of the current module. It is illegal for a function <i>declaration</i>
676to have any linkage type other than "externally visible".</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]677</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]678
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]679<!-- ======================================================================= -->
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]680<div class="doc_subsection">
681 <a name="globalvars">Global Variables</a>
682</div>
683
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]684<div class="doc_text">
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]685
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]686<p>Global variables define regions of memory allocated at compilation
687time instead of run-time. Global variables may optionally be
688initialized. A variable may be defined as a global "constant", which
689indicates that the contents of the variable will never be modified
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]690(opening options for optimization).</p>
691
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]692<p>As SSA values, global variables define pointer values that are in
693scope (i.e. they dominate) for all basic blocks in the program. Global
694variables always define a pointer to their "content" type because they
695describe a region of memory, and all memory objects in LLVM are
696accessed through pointers.</p>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]697
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]698</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]699
700
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]701<!-- ======================================================================= -->
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]702<div class="doc_subsection">
703 <a name="functionstructure">Functions</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]704</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]705
706<div class="doc_text">
707
708<p>LLVM function definitions are composed of a (possibly empty) argument list,
709an opening curly brace, a list of basic blocks, and a closing curly brace. LLVM
710function declarations are defined with the "<tt>declare</tt>" keyword, a
711function name, and a function signature.</p>
712
713<p>A function definition contains a list of basic blocks, forming the CFG for
714the function. Each basic block may optionally start with a label (giving the
715basic block a symbol table entry), contains a list of instructions, and ends
716with a <a href="#terminators">terminator</a> instruction (such as a branch or
717function return).</p>
718
719<p>The first basic block in program is special in two ways: it is immediately
720executed on entrance to the function, and it is not allowed to have predecessor
721basic blocks (i.e. there can not be any branches to the entry block of a
722function). Because the block can have no predecessors, it also cannot have any
723<a href="#i_phi">PHI nodes</a>.</p>
724
725<p>LLVM functions are identified by their name and type signature. Hence, two
726functions with the same name but different parameter lists or return values are
727considered different functions, and LLVM will resolves references to each
728appropriately.</p>
729
730</div>
731
732
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]733<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]734<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
735<!-- *********************************************************************** -->
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]736<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]737<p>The LLVM instruction set consists of several different
738classifications of instructions: <a href="#terminators">terminator
739instructions</a>, <a href="#binaryops">binary instructions</a>, <a
740 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
741instructions</a>.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]742</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]743<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]744<div class="doc_subsection"> <a name="terminators">Terminator
745Instructions</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]746<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]747<p>As mentioned <a href="#functionstructure">previously</a>, every
748basic block in a program ends with a "Terminator" instruction, which
749indicates which block should be executed after the current block is
750finished. These terminator instructions typically yield a '<tt>void</tt>'
751value: they produce control flow, not values (the one exception being
752the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]753<p>There are five different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]754 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
755instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
756the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, and the '<a
757 href="#i_unwind"><tt>unwind</tt></a>' instruction.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]758</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]759<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]760<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
761Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]762<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]763<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]764<pre> ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]765 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]766</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]767<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]768<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
769value) from a function, back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]770<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]771returns a value and then causes control flow, and one that just causes
772control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]773<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]774<p>The '<tt>ret</tt>' instruction may return any '<a
775 href="#t_firstclass">first class</a>' type. Notice that a function is
776not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
777instruction inside of the function that returns a value that does not
778match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]779<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]780<p>When the '<tt>ret</tt>' instruction is executed, control flow
781returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]782 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]783the instruction after the call. If the caller was an "<a
784 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
785at the beginning "normal" of the destination block. If the instruction
786returns a value, that value shall set the call or invoke instruction's
787return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]788<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]789<pre> ret int 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]790 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]791</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]792</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]793<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]794<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]795<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]796<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]797<pre> br bool &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]798</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]799<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]800<p>The '<tt>br</tt>' instruction is used to cause control flow to
801transfer to a different basic block in the current function. There are
802two forms of this instruction, corresponding to a conditional branch
803and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]804<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]805<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
806single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
807unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
808value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]809<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]810<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
811argument is evaluated. If the value is <tt>true</tt>, control flows
812to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
813control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]814<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]815<pre>Test:<br> %cond = <a href="#i_setcc">seteq</a> int %a, %b<br> br bool %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
816 href="#i_ret">ret</a> int 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> int 0<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]817</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]818<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]819<div class="doc_subsubsection">
820 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
821</div>
822
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]823<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]824<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]825
826<pre>
827 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
828</pre>
829
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]830<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]831
832<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
833several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]834instruction, allowing a branch to occur to one of many possible
835destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]836
837
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]838<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]839
840<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
841comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
842an array of pairs of comparison value constants and '<tt>label</tt>'s. The
843table is not allowed to contain duplicate constant entries.</p>
844
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]845<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]846
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]847<p>The <tt>switch</tt> instruction specifies a table of values and
848destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]849table is searched for the given value. If the value is found, control flow is
850transfered to the corresponding destination; otherwise, control flow is
851transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]852
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]853<h5>Implementation:</h5>
854
855<p>Depending on properties of the target machine and the particular
856<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]857ways. For example, it could be generated as a series of chained conditional
858branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]859
860<h5>Example:</h5>
861
862<pre>
863 <i>; Emulate a conditional br instruction</i>
864 %Val = <a href="#i_cast">cast</a> bool %value to int
865 switch int %Val, label %truedest [int 0, label %falsedest ]
866
867 <i>; Emulate an unconditional br instruction</i>
868 switch uint 0, label %dest [ ]
869
870 <i>; Implement a jump table:</i>
871 switch uint %val, label %otherwise [ uint 0, label %onzero
872 uint 1, label %onone
873 uint 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]874</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]875</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]876<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]877<div class="doc_subsubsection"> <a name="i_invoke">'<tt>invoke</tt>'
878Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]879<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]880<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]881<pre> &lt;result&gt; = invoke &lt;ptr to function ty&gt; %&lt;function ptr val&gt;(&lt;function args&gt;)<br> to label &lt;normal label&gt; except label &lt;exception label&gt;<br></pre>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]882<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]883<p>The '<tt>invoke</tt>' instruction causes control to transfer to a
884specified function, with the possibility of control flow transfer to
885either the '<tt>normal</tt>' <tt>label</tt> label or the '<tt>exception</tt>'<tt>label</tt>.
886If the callee function returns with the "<tt><a href="#i_ret">ret</a></tt>"
887instruction, control flow will return to the "normal" label. If the
888callee (or any indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
889instruction, control is interrupted, and continued at the dynamically
890nearest "except" label.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]891<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]892<p>This instruction requires several arguments:</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]893<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]894 <li>'<tt>ptr to function ty</tt>': shall be the signature of the
895pointer to function value being invoked. In most cases, this is a
896direct function invocation, but indirect <tt>invoke</tt>s are just as
897possible, branching off an arbitrary pointer to function value. </li>
898 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer
899to a function to be invoked. </li>
900 <li>'<tt>function args</tt>': argument list whose types match the
901function signature argument types. If the function signature indicates
902the function accepts a variable number of arguments, the extra
903arguments can be specified. </li>
904 <li>'<tt>normal label</tt>': the label reached when the called
905function executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
906 <li>'<tt>exception label</tt>': the label reached when a callee
907returns with the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]908</ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]909<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]910<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]911 href="#i_call">call</a></tt>' instruction in most regards. The
912primary difference is that it establishes an association with a label,
913which is used by the runtime library to unwind the stack.</p>
914<p>This instruction is used in languages with destructors to ensure
915that proper cleanup is performed in the case of either a <tt>longjmp</tt>
916or a thrown exception. Additionally, this is important for
917implementation of '<tt>catch</tt>' clauses in high-level languages that
918support them.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]919<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]920<pre> %retval = invoke int %Test(int 15)<br> to label %Continue<br> except label %TestCleanup <i>; {int}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]921</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]922</div>
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]923<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]924<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
925Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]926<div class="doc_text">
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]927<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]928<pre> unwind<br></pre>
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]929<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]930<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing
931control flow at the first callee in the dynamic call stack which used
932an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the
933call. This is primarily used to implement exception handling.</p>
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]934<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]935<p>The '<tt>unwind</tt>' intrinsic causes execution of the current
936function to immediately halt. The dynamic call stack is then searched
937for the first <a href="#i_invoke"><tt>invoke</tt></a> instruction on
938the call stack. Once found, execution continues at the "exceptional"
939destination block specified by the <tt>invoke</tt> instruction. If
940there is no <tt>invoke</tt> instruction in the dynamic call chain,
941undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]942</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]943<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]944<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]945<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]946<p>Binary operators are used to do most of the computation in a
947program. They require two operands, execute an operation on them, and
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]948produce a single value. Although, that single value might represent
949multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
950The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]951necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]952<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]953</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]954<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]955<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
956Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]957<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]958<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]959<pre> &lt;result&gt; = add &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]960</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]961<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]962<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]963<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]964<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]965 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
966 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
967Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]968<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]969<p>The value produced is the integer or floating point sum of the two
970operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]971<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]972<pre> &lt;result&gt; = add int 4, %var <i>; yields {int}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]973</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]974</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]975<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]976<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
977Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]978<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]979<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]980<pre> &lt;result&gt; = sub &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]981</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]982<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]983<p>The '<tt>sub</tt>' instruction returns the difference of its two
984operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]985<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
986instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]987<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]988<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]989 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]990values.
991This instruction can also take <a href="#t_packed">packed</a> versions of the values.
992Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]993<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]994<p>The value produced is the integer or floating point difference of
995the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]996<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]997<pre> &lt;result&gt; = sub int 4, %var <i>; yields {int}:result = 4 - %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]998 &lt;result&gt; = sub int 0, %val <i>; yields {int}:result = -%var</i>
999</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1000</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1001<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1002<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1003Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1004<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1005<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1006<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1007</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1008<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1009<p>The '<tt>mul</tt>' instruction returns the product of its two
1010operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1011<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1012<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1013 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1014values.
1015This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1016Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1017<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1018<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1019two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1020<p>There is no signed vs unsigned multiplication. The appropriate
1021action is taken based on the type of the operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1022<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1023<pre> &lt;result&gt; = mul int 4, %var <i>; yields {int}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1024</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1025</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1026<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1027<div class="doc_subsubsection"> <a name="i_div">'<tt>div</tt>'
1028Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1029<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1030<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1031<pre> &lt;result&gt; = div &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1032</pre>
1033<h5>Overview:</h5>
1034<p>The '<tt>div</tt>' instruction returns the quotient of its two
1035operands.</p>
1036<h5>Arguments:</h5>
1037<p>The two arguments to the '<tt>div</tt>' instruction must be either <a
1038 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1039values.
1040This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1041Both arguments must have identical types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1042<h5>Semantics:</h5>
1043<p>The value produced is the integer or floating point quotient of the
1044two operands.</p>
1045<h5>Example:</h5>
1046<pre> &lt;result&gt; = div int 4, %var <i>; yields {int}:result = 4 / %var</i>
1047</pre>
1048</div>
1049<!-- _______________________________________________________________________ -->
1050<div class="doc_subsubsection"> <a name="i_rem">'<tt>rem</tt>'
1051Instruction</a> </div>
1052<div class="doc_text">
1053<h5>Syntax:</h5>
1054<pre> &lt;result&gt; = rem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1055</pre>
1056<h5>Overview:</h5>
1057<p>The '<tt>rem</tt>' instruction returns the remainder from the
1058division of its two operands.</p>
1059<h5>Arguments:</h5>
1060<p>The two arguments to the '<tt>rem</tt>' instruction must be either <a
1061 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1062values.
1063This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1064Both arguments must have identical types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1065<h5>Semantics:</h5>
1066<p>This returns the <i>remainder</i> of a division (where the result
1067has the same sign as the divisor), not the <i>modulus</i> (where the
1068result has the same sign as the dividend) of a value. For more
1069information about the difference, see: <a
1070 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1071Math Forum</a>.</p>
1072<h5>Example:</h5>
1073<pre> &lt;result&gt; = rem int 4, %var <i>; yields {int}:result = 4 % %var</i>
1074</pre>
1075</div>
1076<!-- _______________________________________________________________________ -->
1077<div class="doc_subsubsection"> <a name="i_setcc">'<tt>set<i>cc</i></tt>'
1078Instructions</a> </div>
1079<div class="doc_text">
1080<h5>Syntax:</h5>
1081<pre> &lt;result&gt; = seteq &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1082 &lt;result&gt; = setne &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1083 &lt;result&gt; = setlt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1084 &lt;result&gt; = setgt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1085 &lt;result&gt; = setle &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1086 &lt;result&gt; = setge &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1087</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1088<h5>Overview:</h5>
1089<p>The '<tt>set<i>cc</i></tt>' family of instructions returns a boolean
1090value based on a comparison of their two operands.</p>
1091<h5>Arguments:</h5>
1092<p>The two arguments to the '<tt>set<i>cc</i></tt>' instructions must
1093be of <a href="#t_firstclass">first class</a> type (it is not possible
1094to compare '<tt>label</tt>'s, '<tt>array</tt>'s, '<tt>structure</tt>'
1095or '<tt>void</tt>' values, etc...). Both arguments must have identical
1096types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1097<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1098<p>The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1099value if both operands are equal.<br>
1100The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1101value if both operands are unequal.<br>
1102The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1103value if the first operand is less than the second operand.<br>
1104The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1105value if the first operand is greater than the second operand.<br>
1106The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1107value if the first operand is less than or equal to the second operand.<br>
1108The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1109value if the first operand is greater than or equal to the second
1110operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1111<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1112<pre> &lt;result&gt; = seteq int 4, 5 <i>; yields {bool}:result = false</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1113 &lt;result&gt; = setne float 4, 5 <i>; yields {bool}:result = true</i>
1114 &lt;result&gt; = setlt uint 4, 5 <i>; yields {bool}:result = true</i>
1115 &lt;result&gt; = setgt sbyte 4, 5 <i>; yields {bool}:result = false</i>
1116 &lt;result&gt; = setle sbyte 4, 5 <i>; yields {bool}:result = true</i>
1117 &lt;result&gt; = setge sbyte 4, 5 <i>; yields {bool}:result = false</i>
1118</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1119</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1120<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1121<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1122Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1123<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1124<p>Bitwise binary operators are used to do various forms of
1125bit-twiddling in a program. They are generally very efficient
1126instructions, and can commonly be strength reduced from other
1127instructions. They require two operands, execute an operation on them,
1128and produce a single value. The resulting value of the bitwise binary
1129operators is always the same type as its first operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1130</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1131<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1132<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1133Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1134<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1135<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1136<pre> &lt;result&gt; = and &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1137</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1138<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1139<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1140its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1141<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1142<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1143 href="#t_integral">integral</a> values. Both arguments must have
1144identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1145<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1146<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1147<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1148<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1149<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1150 <tbody>
1151 <tr>
1152 <td>In0</td>
1153 <td>In1</td>
1154 <td>Out</td>
1155 </tr>
1156 <tr>
1157 <td>0</td>
1158 <td>0</td>
1159 <td>0</td>
1160 </tr>
1161 <tr>
1162 <td>0</td>
1163 <td>1</td>
1164 <td>0</td>
1165 </tr>
1166 <tr>
1167 <td>1</td>
1168 <td>0</td>
1169 <td>0</td>
1170 </tr>
1171 <tr>
1172 <td>1</td>
1173 <td>1</td>
1174 <td>1</td>
1175 </tr>
1176 </tbody>
1177</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1178</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1179<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1180<pre> &lt;result&gt; = and int 4, %var <i>; yields {int}:result = 4 &amp; %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1181 &lt;result&gt; = and int 15, 40 <i>; yields {int}:result = 8</i>
1182 &lt;result&gt; = and int 4, 8 <i>; yields {int}:result = 0</i>
1183</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1184</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1185<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1186<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1187<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1188<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1189<pre> &lt;result&gt; = or &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1190</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1191<h5>Overview:</h5>
1192<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1193or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1194<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1195<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1196 href="#t_integral">integral</a> values. Both arguments must have
1197identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1198<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1199<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1200<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1201<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1202<table border="1" cellspacing="0" cellpadding="4">
1203 <tbody>
1204 <tr>
1205 <td>In0</td>
1206 <td>In1</td>
1207 <td>Out</td>
1208 </tr>
1209 <tr>
1210 <td>0</td>
1211 <td>0</td>
1212 <td>0</td>
1213 </tr>
1214 <tr>
1215 <td>0</td>
1216 <td>1</td>
1217 <td>1</td>
1218 </tr>
1219 <tr>
1220 <td>1</td>
1221 <td>0</td>
1222 <td>1</td>
1223 </tr>
1224 <tr>
1225 <td>1</td>
1226 <td>1</td>
1227 <td>1</td>
1228 </tr>
1229 </tbody>
1230</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1231</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1232<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1233<pre> &lt;result&gt; = or int 4, %var <i>; yields {int}:result = 4 | %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1234 &lt;result&gt; = or int 15, 40 <i>; yields {int}:result = 47</i>
1235 &lt;result&gt; = or int 4, 8 <i>; yields {int}:result = 12</i>
1236</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1237</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1238<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1239<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
1240Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1241<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1242<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1243<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1244</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1245<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1246<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
1247or of its two operands. The <tt>xor</tt> is used to implement the
1248"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1249<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1250<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1251 href="#t_integral">integral</a> values. Both arguments must have
1252identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1253<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1254<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1255<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1256<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1257<table border="1" cellspacing="0" cellpadding="4">
1258 <tbody>
1259 <tr>
1260 <td>In0</td>
1261 <td>In1</td>
1262 <td>Out</td>
1263 </tr>
1264 <tr>
1265 <td>0</td>
1266 <td>0</td>
1267 <td>0</td>
1268 </tr>
1269 <tr>
1270 <td>0</td>
1271 <td>1</td>
1272 <td>1</td>
1273 </tr>
1274 <tr>
1275 <td>1</td>
1276 <td>0</td>
1277 <td>1</td>
1278 </tr>
1279 <tr>
1280 <td>1</td>
1281 <td>1</td>
1282 <td>0</td>
1283 </tr>
1284 </tbody>
1285</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1286</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1287<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1288<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1289<pre> &lt;result&gt; = xor int 4, %var <i>; yields {int}:result = 4 ^ %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1290 &lt;result&gt; = xor int 15, 40 <i>; yields {int}:result = 39</i>
1291 &lt;result&gt; = xor int 4, 8 <i>; yields {int}:result = 12</i>
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1292 &lt;result&gt; = xor int %V, -1 <i>; yields {int}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1293</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1294</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1295<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1296<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
1297Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1298<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1299<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1300<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1301</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1302<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1303<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
1304the left a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1305<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1306<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1307 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1308type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1309<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1310<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1311<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1312<pre> &lt;result&gt; = shl int 4, ubyte %var <i>; yields {int}:result = 4 &lt;&lt; %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1313 &lt;result&gt; = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
1314 &lt;result&gt; = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
1315</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1316</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1317<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1318<div class="doc_subsubsection"> <a name="i_shr">'<tt>shr</tt>'
1319Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1320<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1321<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1322<pre> &lt;result&gt; = shr &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1323</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1324<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1325<p>The '<tt>shr</tt>' instruction returns the first operand shifted to
1326the right a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1327<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1328<p>The first argument to the '<tt>shr</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1329 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1330type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1331<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1332<p>If the first argument is a <a href="#t_signed">signed</a> type, the
1333most significant bit is duplicated in the newly free'd bit positions.
1334If the first argument is unsigned, zero bits shall fill the empty
1335positions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1336<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1337<pre> &lt;result&gt; = shr int 4, ubyte %var <i>; yields {int}:result = 4 &gt;&gt; %var</i>
Chris Lattner8c6bb902003-06-18 21:30:51 +0000[diff] [blame]1338 &lt;result&gt; = shr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1339 &lt;result&gt; = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
Chris Lattner8c6bb902003-06-18 21:30:51 +0000[diff] [blame]1340 &lt;result&gt; = shr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i>
1341 &lt;result&gt; = shr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1342</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1343</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1344<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1345<div class="doc_subsection"> <a name="memoryops">Memory Access
1346Operations</a></div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1347<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1348<p>A key design point of an SSA-based representation is how it
1349represents memory. In LLVM, no memory locations are in SSA form, which
1350makes things very simple. This section describes how to read, write,
1351allocate and free memory in LLVM.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1352</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1353<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1354<div class="doc_subsubsection"> <a name="i_malloc">'<tt>malloc</tt>'
1355Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1356<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1357<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1358<pre> &lt;result&gt; = malloc &lt;type&gt;, uint &lt;NumElements&gt; <i>; yields {type*}:result</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1359 &lt;result&gt; = malloc &lt;type&gt; <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1360</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1361<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1362<p>The '<tt>malloc</tt>' instruction allocates memory from the system
1363heap and returns a pointer to it.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1364<h5>Arguments:</h5>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]1365<p>The '<tt>malloc</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
1366bytes of memory from the operating system and returns a pointer of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1367appropriate type to the program. The second form of the instruction is
1368a shorter version of the first instruction that defaults to allocating
1369one element.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1370<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1371<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1372<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
1373a pointer is returned.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1374<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1375<pre> %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1376
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1377 %size = <a
1378 href="#i_add">add</a> uint 2, 2 <i>; yields {uint}:size = uint 4</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1379 %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i>
1380 %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1381</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1382</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1383<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1384<div class="doc_subsubsection"> <a name="i_free">'<tt>free</tt>'
1385Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1386<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1387<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1388<pre> free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1389</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1390<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1391<p>The '<tt>free</tt>' instruction returns memory back to the unused
1392memory heap, to be reallocated in the future.</p>
1393<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1394<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1395<p>'<tt>value</tt>' shall be a pointer value that points to a value
1396that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
1397instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1398<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1399<p>Access to the memory pointed to by the pointer is not longer defined
1400after this instruction executes.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1401<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1402<pre> %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1403 free [4 x ubyte]* %array
1404</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1405</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1406<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1407<div class="doc_subsubsection"> <a name="i_alloca">'<tt>alloca</tt>'
1408Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1409<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1410<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1411<pre> &lt;result&gt; = alloca &lt;type&gt;, uint &lt;NumElements&gt; <i>; yields {type*}:result</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1412 &lt;result&gt; = alloca &lt;type&gt; <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1413</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1414<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1415<p>The '<tt>alloca</tt>' instruction allocates memory on the current
1416stack frame of the procedure that is live until the current function
1417returns to its caller.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1418<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1419<p>The the '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
1420bytes of memory on the runtime stack, returning a pointer of the
1421appropriate type to the program. The second form of the instruction is
1422a shorter version of the first that defaults to allocating one element.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1423<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1424<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1425<p>Memory is allocated, a pointer is returned. '<tt>alloca</tt>'d
1426memory is automatically released when the function returns. The '<tt>alloca</tt>'
1427instruction is commonly used to represent automatic variables that must
1428have an address available. When the function returns (either with the <tt><a
1429 href="#i_ret">ret</a></tt> or <tt><a href="#i_invoke">invoke</a></tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1430instructions), the memory is reclaimed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1431<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1432<pre> %ptr = alloca int <i>; yields {int*}:ptr</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1433 %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1434</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1435</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1436<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1437<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
1438Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1439<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1440<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1441<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;<br></pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1442<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1443<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1444<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1445<p>The argument to the '<tt>load</tt>' instruction specifies the memory
1446address to load from. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]1447 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1448marked as <tt>volatile</tt> then the optimizer is not allowed to modify
1449the number or order of execution of this <tt>load</tt> with other
1450volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
1451instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1452<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1453<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1454<h5>Examples:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1455<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
1456 <a
1457 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1458 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
1459</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1460</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1461<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1462<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
1463Instruction</a> </div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1464<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1465<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattnerf0651072003-09-08 18:27:49 +0000[diff] [blame]1466 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1467</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1468<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1469<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1470<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1471<p>There are two arguments to the '<tt>store</tt>' instruction: a value
1472to store and an address to store it into. The type of the '<tt>&lt;pointer&gt;</tt>'
1473operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
1474operand. If the <tt>store</tt> is marked as <tt>volatile</tt> then the
1475optimizer is not allowed to modify the number or order of execution of
1476this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
1477 href="#i_store">store</a></tt> instructions.</p>
1478<h5>Semantics:</h5>
1479<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
1480at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1481<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1482<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
1483 <a
1484 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1485 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
1486</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1487<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1488<div class="doc_subsubsection">
1489 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
1490</div>
1491
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1492<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1493<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1494<pre>
1495 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
1496</pre>
1497
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1498<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1499
1500<p>
1501The '<tt>getelementptr</tt>' instruction is used to get the address of a
1502subelement of an aggregate data structure.</p>
1503
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1504<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1505
1506<p>This instruction takes a list of integer constants that indicate what
1507elements of the aggregate object to index to. The actual types of the arguments
1508provided depend on the type of the first pointer argument. The
1509'<tt>getelementptr</tt>' instruction is used to index down through the type
1510levels of a structure. When indexing into a structure, only <tt>uint</tt>
1511integer constants are allowed. When indexing into an array or pointer
1512<tt>int</tt> and <tt>long</tt> indexes are allowed of any sign.</p>
1513
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1514<p>For example, let's consider a C code fragment and how it gets
1515compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1516
1517<pre>
1518 struct RT {
1519 char A;
1520 int B[10][20];
1521 char C;
1522 };
1523 struct ST {
1524 int X;
1525 double Y;
1526 struct RT Z;
1527 };
1528
1529 int *foo(struct ST *s) {
1530 return &amp;s[1].Z.B[5][13];
1531 }
1532</pre>
1533
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1534<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1535
1536<pre>
1537 %RT = type { sbyte, [10 x [20 x int]], sbyte }
1538 %ST = type { int, double, %RT }
1539
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]1540 implementation
1541
1542 int* %foo(%ST* %s) {
1543 entry:
1544 %reg = getelementptr %ST* %s, int 1, uint 2, uint 1, int 5, int 13
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1545 ret int* %reg
1546 }
1547</pre>
1548
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1549<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1550
1551<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]1552on the pointer type that is being index into. <a href="#t_pointer">Pointer</a>
1553and <a href="#t_array">array</a> types require <tt>uint</tt>, <tt>int</tt>,
1554<tt>ulong</tt>, or <tt>long</tt> values, and <a href="#t_struct">structure</a>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1555types require <tt>uint</tt> <b>constants</b>.</p>
1556
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1557<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1558type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT
1559}</tt>' type, a structure. The second index indexes into the third element of
1560the structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]],
1561sbyte }</tt>' type, another structure. The third index indexes into the second
1562element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an
1563array. The two dimensions of the array are subscripted into, yielding an
1564'<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction return a pointer
1565to this element, thus computing a value of '<tt>int*</tt>' type.</p>
1566
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1567<p>Note that it is perfectly legal to index partially through a
1568structure, returning a pointer to an inner element. Because of this,
1569the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1570
1571<pre>
1572 int* "foo"(%ST* %s) {
1573 %t1 = getelementptr %ST* %s, int 1 <i>; yields %ST*:%t1</i>
1574 %t2 = getelementptr %ST* %t1, int 0, uint 2 <i>; yields %RT*:%t2</i>
1575 %t3 = getelementptr %RT* %t2, int 0, uint 1 <i>; yields [10 x [20 x int]]*:%t3</i>
1576 %t4 = getelementptr [10 x [20 x int]]* %t3, int 0, int 5 <i>; yields [20 x int]*:%t4</i>
1577 %t5 = getelementptr [20 x int]* %t4, int 0, int 13 <i>; yields int*:%t5</i>
1578 ret int* %t5
1579 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1580</pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1581<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1582<pre>
1583 <i>; yields [12 x ubyte]*:aptr</i>
1584 %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, uint 1
1585</pre>
1586
1587</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1588<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1589<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1590<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1591<p>The instructions in this category are the "miscellaneous"
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1592instructions, which defy better classification.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1593</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1594<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1595<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
1596Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1597<div class="doc_text">
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1598<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1599<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1600<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1601<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
1602the SSA graph representing the function.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1603<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1604<p>The type of the incoming values are specified with the first type
1605field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
1606as arguments, with one pair for each predecessor basic block of the
1607current block. Only values of <a href="#t_firstclass">first class</a>
1608type may be used as the value arguments to the PHI node. Only labels
1609may be used as the label arguments.</p>
1610<p>There must be no non-phi instructions between the start of a basic
1611block and the PHI instructions: i.e. PHI instructions must be first in
1612a basic block.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1613<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1614<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
1615value specified by the parameter, depending on which basic block we
1616came from in the last <a href="#terminators">terminator</a> instruction.</p>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1617<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1618<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi uint [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add uint %indvar, 1<br> br label %Loop<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1619</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1620
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1621<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1622<div class="doc_subsubsection">
1623 <a name="i_cast">'<tt>cast .. to</tt>' Instruction</a>
1624</div>
1625
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1626<div class="doc_text">
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1627
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1628<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1629
1630<pre>
1631 &lt;result&gt; = cast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1632</pre>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1633
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1634<h5>Overview:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1635
1636<p>
1637The '<tt>cast</tt>' instruction is used as the primitive means to convert
1638integers to floating point, change data type sizes, and break type safety (by
1639casting pointers).
1640</p>
1641
1642
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1643<h5>Arguments:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1644
1645<p>
1646The '<tt>cast</tt>' instruction takes a value to cast, which must be a first
1647class value, and a type to cast it to, which must also be a <a
1648href="#t_firstclass">first class</a> type.
1649</p>
1650
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1651<h5>Semantics:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1652
1653<p>
1654This instruction follows the C rules for explicit casts when determining how the
1655data being cast must change to fit in its new container.
1656</p>
1657
1658<p>
1659When casting to bool, any value that would be considered true in the context of
1660a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' values,
1661all else are '<tt>false</tt>'.
1662</p>
1663
1664<p>
1665When extending an integral value from a type of one signness to another (for
1666example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value is sign-extended if the
1667<b>source</b> value is signed, and zero-extended if the source value is
1668unsigned. <tt>bool</tt> values are always zero extended into either zero or
1669one.
1670</p>
1671
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1672<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1673
1674<pre>
1675 %X = cast int 257 to ubyte <i>; yields ubyte:1</i>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame]1676 %Y = cast int 123 to bool <i>; yields bool:true</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1677</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1678</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1679
1680<!-- _______________________________________________________________________ -->
1681<div class="doc_subsubsection">
1682 <a name="i_select">'<tt>select</tt>' Instruction</a>
1683</div>
1684
1685<div class="doc_text">
1686
1687<h5>Syntax:</h5>
1688
1689<pre>
1690 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
1691</pre>
1692
1693<h5>Overview:</h5>
1694
1695<p>
1696The '<tt>select</tt>' instruction is used to choose one value based on a
1697condition, without branching.
1698</p>
1699
1700
1701<h5>Arguments:</h5>
1702
1703<p>
1704The '<tt>select</tt>' instruction requires a boolean value indicating the condition, and two values of the same <a href="#t_firstclass">first class</a> type.
1705</p>
1706
1707<h5>Semantics:</h5>
1708
1709<p>
1710If the boolean condition evaluates to true, the instruction returns the first
1711value argument, otherwise it returns the second value argument.
1712</p>
1713
1714<h5>Example:</h5>
1715
1716<pre>
1717 %X = select bool true, ubyte 17, ubyte 42 <i>; yields ubyte:17</i>
1718</pre>
1719</div>
1720
1721
1722
1723
1724
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1725<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1726<div class="doc_subsubsection"> <a name="i_call">'<tt>call</tt>'
1727Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1728<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1729<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1730<pre> &lt;result&gt; = call &lt;ty&gt;* &lt;fnptrval&gt;(&lt;param list&gt;)<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1731<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1732<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1733<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1734<p>This instruction requires several arguments:</p>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1735<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1736 <li>
1737 <p>'<tt>ty</tt>': shall be the signature of the pointer to function
1738value being invoked. The argument types must match the types implied
1739by this signature.</p>
1740 </li>
1741 <li>
1742 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a
1743function to be invoked. In most cases, this is a direct function
1744invocation, but indirect <tt>call</tt>s are just as possible,
1745calling an arbitrary pointer to function values.</p>
1746 </li>
1747 <li>
1748 <p>'<tt>function args</tt>': argument list whose types match the
1749function signature argument types. If the function signature
1750indicates the function accepts a variable number of arguments, the
1751extra arguments can be specified.</p>
1752 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1753</ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1754<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1755<p>The '<tt>call</tt>' instruction is used to cause control flow to
1756transfer to a specified function, with its incoming arguments bound to
1757the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
1758instruction in the called function, control flow continues with the
1759instruction after the function call, and the return value of the
1760function is bound to the result argument. This is a simpler case of
1761the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1762<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1763<pre> %retval = call int %test(int %argc)<br> call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42);<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1764</div>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1765<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1766<div class="doc_subsubsection"> <a name="i_vanext">'<tt>vanext</tt>'
1767Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1768<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1769<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1770<pre> &lt;resultarglist&gt; = vanext &lt;va_list&gt; &lt;arglist&gt;, &lt;argty&gt;<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1771<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1772<p>The '<tt>vanext</tt>' instruction is used to access arguments passed
1773through the "variable argument" area of a function call. It is used to
1774implement the <tt>va_arg</tt> macro in C.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1775<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1776<p>This instruction takes a <tt>valist</tt> value and the type of the
1777argument. It returns another <tt>valist</tt>.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1778<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1779<p>The '<tt>vanext</tt>' instruction advances the specified <tt>valist</tt>
1780past an argument of the specified type. In conjunction with the <a
1781 href="#i_vaarg"><tt>vaarg</tt></a> instruction, it is used to implement
1782the <tt>va_arg</tt> macro available in C. For more information, see
1783the variable argument handling <a href="#int_varargs">Intrinsic
1784Functions</a>.</p>
1785<p>It is legal for this instruction to be called in a function which
1786does not take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1787function.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1788<p><tt>vanext</tt> is an LLVM instruction instead of an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1789 href="#intrinsics">intrinsic function</a> because it takes an type as
1790an argument.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1791<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1792<p>See the <a href="#int_varargs">variable argument processing</a>
1793section.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1794</div>
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]1795<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1796<div class="doc_subsubsection"> <a name="i_vaarg">'<tt>vaarg</tt>'
1797Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1798<div class="doc_text">
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]1799<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1800<pre> &lt;resultval&gt; = vaarg &lt;va_list&gt; &lt;arglist&gt;, &lt;argty&gt;<br></pre>
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]1801<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1802<p>The '<tt>vaarg</tt>' instruction is used to access arguments passed
1803through the "variable argument" area of a function call. It is used to
1804implement the <tt>va_arg</tt> macro in C.</p>
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]1805<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1806<p>This instruction takes a <tt>valist</tt> value and the type of the
1807argument. It returns a value of the specified argument type.</p>
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]1808<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1809<p>The '<tt>vaarg</tt>' instruction loads an argument of the specified
1810type from the specified <tt>va_list</tt>. In conjunction with the <a
1811 href="#i_vanext"><tt>vanext</tt></a> instruction, it is used to
1812implement the <tt>va_arg</tt> macro available in C. For more
1813information, see the variable argument handling <a href="#int_varargs">Intrinsic
1814Functions</a>.</p>
1815<p>It is legal for this instruction to be called in a function which
1816does not take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1817function.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1818<p><tt>vaarg</tt> is an LLVM instruction instead of an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1819 href="#intrinsics">intrinsic function</a> because it takes an type as
1820an argument.</p>
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]1821<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1822<p>See the <a href="#int_varargs">variable argument processing</a>
1823section.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1824</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1825
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1826<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1827<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
1828<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1829
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1830<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]1831
1832<p>LLVM supports the notion of an "intrinsic function". These functions have
1833well known names and semantics, and are required to follow certain
1834restrictions. Overall, these instructions represent an extension mechanism for
1835the LLVM language that does not require changing all of the transformations in
1836LLVM to add to the language (or the bytecode reader/writer, the parser,
1837etc...).</p>
1838
1839<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix, this
1840prefix is reserved in LLVM for intrinsic names, thus functions may not be named
1841this. Intrinsic functions must always be external functions: you cannot define
1842the body of intrinsic functions. Intrinsic functions may only be used in call
1843or invoke instructions: it is illegal to take the address of an intrinsic
1844function. Additionally, because intrinsic functions are part of the LLVM
1845language, it is required that they all be documented here if any are added.</p>
1846
1847
1848<p>
1849Adding an intrinsic to LLVM is straight-forward if it is possible to express the
1850concept in LLVM directly (ie, code generator support is not _required_). To do
1851this, extend the default implementation of the IntrinsicLowering class to handle
1852the intrinsic. Code generators use this class to lower intrinsics they do not
1853understand to raw LLVM instructions that they do.
1854</p>
1855
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1856</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1857
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1858<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1859<div class="doc_subsection">
1860 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
1861</div>
1862
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1863<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]1864
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1865<p>Variable argument support is defined in LLVM with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1866 href="#i_vanext"><tt>vanext</tt></a> instruction and these three
1867intrinsic functions. These functions are related to the similarly
1868named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]1869
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1870<p>All of these functions operate on arguments that use a
1871target-specific value type "<tt>va_list</tt>". The LLVM assembly
1872language reference manual does not define what this type is, so all
1873transformations should be prepared to handle intrinsics with any type
1874used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]1875
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1876<p>This example shows how the <a href="#i_vanext"><tt>vanext</tt></a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1877instruction and the variable argument handling intrinsic functions are
1878used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]1879
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]1880<pre>
1881int %test(int %X, ...) {
1882 ; Initialize variable argument processing
1883 %ap = call sbyte* %<a href="#i_va_start">llvm.va_start</a>()
1884
1885 ; Read a single integer argument
1886 %tmp = vaarg sbyte* %ap, int
1887
1888 ; Advance to the next argument
1889 %ap2 = vanext sbyte* %ap, int
1890
1891 ; Demonstrate usage of llvm.va_copy and llvm.va_end
1892 %aq = call sbyte* %<a href="#i_va_copy">llvm.va_copy</a>(sbyte* %ap2)
1893 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %aq)
1894
1895 ; Stop processing of arguments.
1896 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %ap2)
1897 ret int %tmp
1898}
1899</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1900</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1901
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1902<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1903<div class="doc_subsubsection">
1904 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
1905</div>
1906
1907
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1908<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1909<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1910<pre> call va_list ()* %llvm.va_start()<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1911<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1912<p>The '<tt>llvm.va_start</tt>' intrinsic returns a new <tt>&lt;arglist&gt;</tt>
1913for subsequent use by the variable argument intrinsics.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1914<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1915<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1916macro available in C. In a target-dependent way, it initializes and
1917returns a <tt>va_list</tt> element, so that the next <tt>vaarg</tt>
1918will produce the first variable argument passed to the function. Unlike
1919the C <tt>va_start</tt> macro, this intrinsic does not need to know the
1920last argument of the function, the compiler can figure that out.</p>
1921<p>Note that this intrinsic function is only legal to be called from
1922within the body of a variable argument function.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1923</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1924
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1925<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1926<div class="doc_subsubsection">
1927 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
1928</div>
1929
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1930<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1931<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1932<pre> call void (va_list)* %llvm.va_end(va_list &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1933<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1934<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
1935which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
1936or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1937<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1938<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1939<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1940<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1941macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
1942Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
1943 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
1944with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1945</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1946
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1947<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1948<div class="doc_subsubsection">
1949 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
1950</div>
1951
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1952<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]1953
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1954<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]1955
1956<pre>
1957 call va_list (va_list)* %llvm.va_copy(va_list &lt;destarglist&gt;)
1958</pre>
1959
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1960<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]1961
1962<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
1963from the source argument list to the destination argument list.</p>
1964
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1965<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]1966
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1967<p>The argument is the <tt>va_list</tt> to copy.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]1968
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]1969<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]1970
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1971<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]1972macro available in C. In a target-dependent way, it copies the source
1973<tt>va_list</tt> element into the returned list. This intrinsic is necessary
Chris Lattnerfcd37252004-06-21 22:52:48 +0000[diff] [blame]1974because the <tt><a href="#i_va_start">llvm.va_start</a></tt> intrinsic may be
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]1975arbitrarily complex and require memory allocation, for example.</p>
1976
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1977</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1978
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]1979<!-- ======================================================================= -->
1980<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]1981 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
1982</div>
1983
1984<div class="doc_text">
1985
1986<p>
1987LLVM support for <a href="GarbageCollection.html">Accurate Garbage
1988Collection</a> requires the implementation and generation of these intrinsics.
1989These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
1990stack</a>, as well as garbage collector implementations that require <a
1991href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
1992Front-ends for type-safe garbage collected languages should generate these
1993intrinsics to make use of the LLVM garbage collectors. For more details, see <a
1994href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
1995</p>
1996</div>
1997
1998<!-- _______________________________________________________________________ -->
1999<div class="doc_subsubsection">
2000 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
2001</div>
2002
2003<div class="doc_text">
2004
2005<h5>Syntax:</h5>
2006
2007<pre>
2008 call void (&lt;ty&gt;**, &lt;ty2&gt;*)* %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
2009</pre>
2010
2011<h5>Overview:</h5>
2012
2013<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existance of a GC root to
2014the code generator, and allows some metadata to be associated with it.</p>
2015
2016<h5>Arguments:</h5>
2017
2018<p>The first argument specifies the address of a stack object that contains the
2019root pointer. The second pointer (which must be either a constant or a global
2020value address) contains the meta-data to be associated with the root.</p>
2021
2022<h5>Semantics:</h5>
2023
2024<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
2025location. At compile-time, the code generator generates information to allow
2026the runtime to find the pointer at GC safe points.
2027</p>
2028
2029</div>
2030
2031
2032<!-- _______________________________________________________________________ -->
2033<div class="doc_subsubsection">
2034 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
2035</div>
2036
2037<div class="doc_text">
2038
2039<h5>Syntax:</h5>
2040
2041<pre>
2042 call sbyte* (sbyte**)* %llvm.gcread(sbyte** %Ptr)
2043</pre>
2044
2045<h5>Overview:</h5>
2046
2047<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
2048locations, allowing garbage collector implementations that require read
2049barriers.</p>
2050
2051<h5>Arguments:</h5>
2052
2053<p>The argument is the address to read from, which should be an address
2054allocated from the garbage collector.</p>
2055
2056<h5>Semantics:</h5>
2057
2058<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
2059instruction, but may be replaced with substantially more complex code by the
2060garbage collector runtime, as needed.</p>
2061
2062</div>
2063
2064
2065<!-- _______________________________________________________________________ -->
2066<div class="doc_subsubsection">
2067 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
2068</div>
2069
2070<div class="doc_text">
2071
2072<h5>Syntax:</h5>
2073
2074<pre>
2075 call void (sbyte*, sbyte**)* %llvm.gcwrite(sbyte* %P1, sbyte** %P2)
2076</pre>
2077
2078<h5>Overview:</h5>
2079
2080<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
2081locations, allowing garbage collector implementations that require write
2082barriers (such as generational or reference counting collectors).</p>
2083
2084<h5>Arguments:</h5>
2085
2086<p>The first argument is the reference to store, and the second is the heap
2087location to store to.</p>
2088
2089<h5>Semantics:</h5>
2090
2091<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
2092instruction, but may be replaced with substantially more complex code by the
2093garbage collector runtime, as needed.</p>
2094
2095</div>
2096
2097
2098
2099<!-- ======================================================================= -->
2100<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2101 <a name="int_codegen">Code Generator Intrinsics</a>
2102</div>
2103
2104<div class="doc_text">
2105<p>
2106These intrinsics are provided by LLVM to expose special features that may only
2107be implemented with code generator support.
2108</p>
2109
2110</div>
2111
2112<!-- _______________________________________________________________________ -->
2113<div class="doc_subsubsection">
2114 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
2115</div>
2116
2117<div class="doc_text">
2118
2119<h5>Syntax:</h5>
2120<pre>
2121 call void* ()* %llvm.returnaddress(uint &lt;level&gt;)
2122</pre>
2123
2124<h5>Overview:</h5>
2125
2126<p>
2127The '<tt>llvm.returnaddress</tt>' intrinsic returns a target-specific value
2128indicating the return address of the current function or one of its callers.
2129</p>
2130
2131<h5>Arguments:</h5>
2132
2133<p>
2134The argument to this intrinsic indicates which function to return the address
2135for. Zero indicates the calling function, one indicates its caller, etc. The
2136argument is <b>required</b> to be a constant integer value.
2137</p>
2138
2139<h5>Semantics:</h5>
2140
2141<p>
2142The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
2143the return address of the specified call frame, or zero if it cannot be
2144identified. The value returned by this intrinsic is likely to be incorrect or 0
2145for arguments other than zero, so it should only be used for debugging purposes.
2146</p>
2147
2148<p>
2149Note that calling this intrinsic does not prevent function inlining or other
2150aggressive transformations, so the value returned may not that of the obvious
2151source-language caller.
2152</p>
2153</div>
2154
2155
2156<!-- _______________________________________________________________________ -->
2157<div class="doc_subsubsection">
2158 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
2159</div>
2160
2161<div class="doc_text">
2162
2163<h5>Syntax:</h5>
2164<pre>
2165 call void* ()* %llvm.frameaddress(uint &lt;level&gt;)
2166</pre>
2167
2168<h5>Overview:</h5>
2169
2170<p>
2171The '<tt>llvm.frameaddress</tt>' intrinsic returns the target-specific frame
2172pointer value for the specified stack frame.
2173</p>
2174
2175<h5>Arguments:</h5>
2176
2177<p>
2178The argument to this intrinsic indicates which function to return the frame
2179pointer for. Zero indicates the calling function, one indicates its caller,
2180etc. The argument is <b>required</b> to be a constant integer value.
2181</p>
2182
2183<h5>Semantics:</h5>
2184
2185<p>
2186The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
2187the frame address of the specified call frame, or zero if it cannot be
2188identified. The value returned by this intrinsic is likely to be incorrect or 0
2189for arguments other than zero, so it should only be used for debugging purposes.
2190</p>
2191
2192<p>
2193Note that calling this intrinsic does not prevent function inlining or other
2194aggressive transformations, so the value returned may not that of the obvious
2195source-language caller.
2196</p>
2197</div>
2198
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2199<!-- ======================================================================= -->
2200<div class="doc_subsection">
2201 <a name="int_os">Operating System Intrinsics</a>
2202</div>
2203
2204<div class="doc_text">
2205<p>
2206These intrinsics are provided by LLVM to support the implementation of
2207operating system level code.
2208</p>
2209
2210</div>
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2211
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2212<!-- _______________________________________________________________________ -->
2213<div class="doc_subsubsection">
2214 <a name="i_readport">'<tt>llvm.readport</tt>' Intrinsic</a>
2215</div>
2216
2217<div class="doc_text">
2218
2219<h5>Syntax:</h5>
2220<pre>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2221 call &lt;integer type&gt; (&lt;integer type&gt;)* %llvm.readport (&lt;integer type&gt; &lt;address&gt;)
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2222</pre>
2223
2224<h5>Overview:</h5>
2225
2226<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2227The '<tt>llvm.readport</tt>' intrinsic reads data from the specified hardware
2228I/O port.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2229</p>
2230
2231<h5>Arguments:</h5>
2232
2233<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2234The argument to this intrinsic indicates the hardware I/O address from which
2235to read the data. The address is in the hardware I/O address namespace (as
2236opposed to being a memory location for memory mapped I/O).
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2237</p>
2238
2239<h5>Semantics:</h5>
2240
2241<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2242The '<tt>llvm.readport</tt>' intrinsic reads data from the hardware I/O port
2243specified by <i>address</i> and returns the value. The address and return
2244value must be integers, but the size is dependent upon the platform upon which
2245the program is code generated. For example, on x86, the address must be an
2246unsigned 16 bit value, and the return value must be 8, 16, or 32 bits.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2247</p>
2248
2249</div>
2250
2251<!-- _______________________________________________________________________ -->
2252<div class="doc_subsubsection">
2253 <a name="i_writeport">'<tt>llvm.writeport</tt>' Intrinsic</a>
2254</div>
2255
2256<div class="doc_text">
2257
2258<h5>Syntax:</h5>
2259<pre>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2260 call void (&lt;integer type&gt;, &lt;integer type&gt;)* %llvm.writeport (&lt;integer type&gt; &lt;value&gt;, &lt;integer type&gt; &lt;address&gt;)
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2261</pre>
2262
2263<h5>Overview:</h5>
2264
2265<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2266The '<tt>llvm.writeport</tt>' intrinsic writes data to the specified hardware
2267I/O port.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2268</p>
2269
2270<h5>Arguments:</h5>
2271
2272<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2273The first argument is the value to write to the I/O port.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2274</p>
2275
2276<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2277The second argument indicates the hardware I/O address to which data should be
2278written. The address is in the hardware I/O address namespace (as opposed to
2279being a memory location for memory mapped I/O).
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2280</p>
2281
2282<h5>Semantics:</h5>
2283
2284<p>
2285The '<tt>llvm.writeport</tt>' intrinsic writes <i>value</i> to the I/O port
2286specified by <i>address</i>. The address and value must be integers, but the
2287size is dependent upon the platform upon which the program is code generated.
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2288For example, on x86, the address must be an unsigned 16 bit value, and the
2289value written must be 8, 16, or 32 bits in length.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2290</p>
2291
2292</div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2293
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2294<!-- _______________________________________________________________________ -->
2295<div class="doc_subsubsection">
2296 <a name="i_readio">'<tt>llvm.readio</tt>' Intrinsic</a>
2297</div>
2298
2299<div class="doc_text">
2300
2301<h5>Syntax:</h5>
2302<pre>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2303 call &lt;result&gt; (&lt;ty&gt;*)* %llvm.readio (&lt;ty&gt; * &lt;pointer&gt;)
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2304</pre>
2305
2306<h5>Overview:</h5>
2307
2308<p>
2309The '<tt>llvm.readio</tt>' intrinsic reads data from a memory mapped I/O
2310address.
2311</p>
2312
2313<h5>Arguments:</h5>
2314
2315<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2316The argument to this intrinsic is a pointer indicating the memory address from
2317which to read the data. The data must be a
2318<a href="#t_firstclass">first class</a> type.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2319</p>
2320
2321<h5>Semantics:</h5>
2322
2323<p>
2324The '<tt>llvm.readio</tt>' intrinsic reads data from a memory mapped I/O
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2325location specified by <i>pointer</i> and returns the value. The argument must
2326be a pointer, and the return value must be a
2327<a href="#t_firstclass">first class</a> type. However, certain architectures
2328may not support I/O on all first class types. For example, 32 bit processors
2329may only support I/O on data types that are 32 bits or less.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2330</p>
2331
2332<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2333This intrinsic enforces an in-order memory model for llvm.readio and
2334llvm.writeio calls on machines that use dynamic scheduling. Dynamically
2335scheduled processors may execute loads and stores out of order, re-ordering at
2336run time accesses to memory mapped I/O registers. Using these intrinsics
2337ensures that accesses to memory mapped I/O registers occur in program order.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2338</p>
2339
2340</div>
2341
2342<!-- _______________________________________________________________________ -->
2343<div class="doc_subsubsection">
2344 <a name="i_writeio">'<tt>llvm.writeio</tt>' Intrinsic</a>
2345</div>
2346
2347<div class="doc_text">
2348
2349<h5>Syntax:</h5>
2350<pre>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2351 call void (&lt;ty1&gt;, &lt;ty2&gt;*)* %llvm.writeio (&lt;ty1&gt; &lt;value&gt;, &lt;ty2&gt; * &lt;pointer&gt;)
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2352</pre>
2353
2354<h5>Overview:</h5>
2355
2356<p>
2357The '<tt>llvm.writeio</tt>' intrinsic writes data to the specified memory
2358mapped I/O address.
2359</p>
2360
2361<h5>Arguments:</h5>
2362
2363<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2364The first argument is the value to write to the memory mapped I/O location.
2365The second argument is a pointer indicating the memory address to which the
2366data should be written.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2367</p>
2368
2369<h5>Semantics:</h5>
2370
2371<p>
2372The '<tt>llvm.writeio</tt>' intrinsic writes <i>value</i> to the memory mapped
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2373I/O address specified by <i>pointer</i>. The value must be a
2374<a href="#t_firstclass">first class</a> type. However, certain architectures
2375may not support I/O on all first class types. For example, 32 bit processors
2376may only support I/O on data types that are 32 bits or less.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2377</p>
2378
2379<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2380This intrinsic enforces an in-order memory model for llvm.readio and
2381llvm.writeio calls on machines that use dynamic scheduling. Dynamically
2382scheduled processors may execute loads and stores out of order, re-ordering at
2383run time accesses to memory mapped I/O registers. Using these intrinsics
2384ensures that accesses to memory mapped I/O registers occur in program order.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2385</p>
2386
2387</div>
2388
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2389<!-- ======================================================================= -->
2390<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2391 <a name="int_libc">Standard C Library Intrinsics</a>
2392</div>
2393
2394<div class="doc_text">
2395<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2396LLVM provides intrinsics for a few important standard C library functions.
2397These intrinsics allow source-language front-ends to pass information about the
2398alignment of the pointer arguments to the code generator, providing opportunity
2399for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2400</p>
2401
2402</div>
2403
2404<!-- _______________________________________________________________________ -->
2405<div class="doc_subsubsection">
2406 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
2407</div>
2408
2409<div class="doc_text">
2410
2411<h5>Syntax:</h5>
2412<pre>
2413 call void (sbyte*, sbyte*, uint, uint)* %llvm.memcpy(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
2414 uint &lt;len&gt;, uint &lt;align&gt;)
2415</pre>
2416
2417<h5>Overview:</h5>
2418
2419<p>
2420The '<tt>llvm.memcpy</tt>' intrinsic copies a block of memory from the source
2421location to the destination location.
2422</p>
2423
2424<p>
2425Note that, unlike the standard libc function, the <tt>llvm.memcpy</tt> intrinsic
2426does not return a value, and takes an extra alignment argument.
2427</p>
2428
2429<h5>Arguments:</h5>
2430
2431<p>
2432The first argument is a pointer to the destination, the second is a pointer to
2433the source. The third argument is an (arbitrarily sized) integer argument
2434specifying the number of bytes to copy, and the fourth argument is the alignment
2435of the source and destination locations.
2436</p>
2437
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]2438<p>
2439If the call to this intrinisic has an alignment value that is not 0 or 1, then
2440the caller guarantees that the size of the copy is a multiple of the alignment
2441and that both the source and destination pointers are aligned to that boundary.
2442</p>
2443
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2444<h5>Semantics:</h5>
2445
2446<p>
2447The '<tt>llvm.memcpy</tt>' intrinsic copies a block of memory from the source
2448location to the destination location, which are not allowed to overlap. It
2449copies "len" bytes of memory over. If the argument is known to be aligned to
2450some boundary, this can be specified as the fourth argument, otherwise it should
2451be set to 0 or 1.
2452</p>
2453</div>
2454
2455
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]2456<!-- _______________________________________________________________________ -->
2457<div class="doc_subsubsection">
2458 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
2459</div>
2460
2461<div class="doc_text">
2462
2463<h5>Syntax:</h5>
2464<pre>
2465 call void (sbyte*, sbyte*, uint, uint)* %llvm.memmove(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
2466 uint &lt;len&gt;, uint &lt;align&gt;)
2467</pre>
2468
2469<h5>Overview:</h5>
2470
2471<p>
2472The '<tt>llvm.memmove</tt>' intrinsic moves a block of memory from the source
2473location to the destination location. It is similar to the '<tt>llvm.memcpy</tt>'
2474intrinsic but allows the two memory locations to overlap.
2475</p>
2476
2477<p>
2478Note that, unlike the standard libc function, the <tt>llvm.memmove</tt> intrinsic
2479does not return a value, and takes an extra alignment argument.
2480</p>
2481
2482<h5>Arguments:</h5>
2483
2484<p>
2485The first argument is a pointer to the destination, the second is a pointer to
2486the source. The third argument is an (arbitrarily sized) integer argument
2487specifying the number of bytes to copy, and the fourth argument is the alignment
2488of the source and destination locations.
2489</p>
2490
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]2491<p>
2492If the call to this intrinisic has an alignment value that is not 0 or 1, then
2493the caller guarantees that the size of the copy is a multiple of the alignment
2494and that both the source and destination pointers are aligned to that boundary.
2495</p>
2496
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]2497<h5>Semantics:</h5>
2498
2499<p>
2500The '<tt>llvm.memmove</tt>' intrinsic copies a block of memory from the source
2501location to the destination location, which may overlap. It
2502copies "len" bytes of memory over. If the argument is known to be aligned to
2503some boundary, this can be specified as the fourth argument, otherwise it should
2504be set to 0 or 1.
2505</p>
2506</div>
2507
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2508
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2509<!-- _______________________________________________________________________ -->
2510<div class="doc_subsubsection">
2511 <a name="i_memset">'<tt>llvm.memset</tt>' Intrinsic</a>
2512</div>
2513
2514<div class="doc_text">
2515
2516<h5>Syntax:</h5>
2517<pre>
2518 call void (sbyte*, ubyte, uint, uint)* %llvm.memset(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
2519 uint &lt;len&gt;, uint &lt;align&gt;)
2520</pre>
2521
2522<h5>Overview:</h5>
2523
2524<p>
2525The '<tt>llvm.memset</tt>' intrinsic fills a block of memory with a particular
2526byte value.
2527</p>
2528
2529<p>
2530Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
2531does not return a value, and takes an extra alignment argument.
2532</p>
2533
2534<h5>Arguments:</h5>
2535
2536<p>
2537The first argument is a pointer to the destination to fill, the second is the
2538byte value to fill it with, the third argument is an (arbitrarily sized) integer
2539argument specifying the number of bytes to fill, and the fourth argument is the
2540known alignment of destination location.
2541</p>
2542
2543<p>
2544If the call to this intrinisic has an alignment value that is not 0 or 1, then
2545the caller guarantees that the size of the copy is a multiple of the alignment
2546and that the destination pointer is aligned to that boundary.
2547</p>
2548
2549<h5>Semantics:</h5>
2550
2551<p>
2552The '<tt>llvm.memset</tt>' intrinsic fills "len" bytes of memory starting at the
2553destination location. If the argument is known to be aligned to some boundary,
2554this can be specified as the fourth argument, otherwise it should be set to 0 or
25551.
2556</p>
2557</div>
2558
2559
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]2560<!-- _______________________________________________________________________ -->
2561<div class="doc_subsubsection">
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]2562 <a name="i_isunordered">'<tt>llvm.isunordered</tt>' Intrinsic</a>
2563</div>
2564
2565<div class="doc_text">
2566
2567<h5>Syntax:</h5>
2568<pre>
2569 call bool (&lt;float or double&gt;, &lt;float or double&gt;)* %llvm.isunordered(&lt;float or double&gt; Val1,
2570 &lt;float or double&gt; Val2)
2571</pre>
2572
2573<h5>Overview:</h5>
2574
2575<p>
2576The '<tt>llvm.isunordered</tt>' intrinsic returns true if either or both of the
2577specified floating point values is a NAN.
2578</p>
2579
2580<h5>Arguments:</h5>
2581
2582<p>
2583The arguments are floating point numbers of the same type.
2584</p>
2585
2586<h5>Semantics:</h5>
2587
2588<p>
2589If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
2590false.
2591</p>
2592</div>
2593
2594
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]2595
2596
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2597<!-- ======================================================================= -->
2598<div class="doc_subsection">
2599 <a name="int_debugger">Debugger Intrinsics</a>
2600</div>
2601
2602<div class="doc_text">
2603<p>
2604The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
2605are described in the <a
2606href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
2607Debugging</a> document.
2608</p>
2609</div>
2610
2611
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2612<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2613<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2614<address>
2615 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
2616 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
2617 <a href="http://validator.w3.org/check/referer"><img
2618 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
2619
2620 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
2621 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
2622 Last modified: $Date$
2623</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2624</body>
2625</html>