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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
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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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
26 <li><a href="#functionstructure">Function Structure</a></li>
27 </ol>
28 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]29 <li><a href="#typesystem">Type System</a>
30 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]31 <li><a href="#t_primitive">Primitive Types</a>
32 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]33 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]34 </ol>
35 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]36 <li><a href="#t_derived">Derived Types</a>
37 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]38 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]39 <li><a href="#t_function">Function Type</a></li>
40 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]41 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]42 <li><a href="#t_packed">Packed Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]43 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]44 </ol>
45 </li>
46 </ol>
47 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]48 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]49 <ol>
50 <li><a href="#simpleconstants">Simple Constants</a>
51 <li><a href="#aggregateconstants">Aggregate Constants</a>
52 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
53 <li><a href="#undefvalues">Undefined Values</a>
54 <li><a href="#constantexprs">Constant Expressions</a>
55 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]56 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]57 <li><a href="#instref">Instruction Reference</a>
58 <ol>
59 <li><a href="#terminators">Terminator Instructions</a>
60 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]61 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
62 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]63 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
64 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]65 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]66 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]67 </ol>
68 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]69 <li><a href="#binaryops">Binary Operations</a>
70 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
72 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
73 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
74 <li><a href="#i_div">'<tt>div</tt>' Instruction</a></li>
75 <li><a href="#i_rem">'<tt>rem</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]76 <li><a href="#i_setcc">'<tt>set<i>cc</i></tt>' Instructions</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]77 </ol>
78 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]79 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
80 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]81 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]82 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]83 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
84 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
85 <li><a href="#i_shr">'<tt>shr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]86 </ol>
87 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]88 <li><a href="#memoryops">Memory Access Operations</a>
89 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]90 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
91 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
92 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
93 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
94 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
95 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
96 </ol>
97 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]98 <li><a href="#otherops">Other Operations</a>
99 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]100 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]101 <li><a href="#i_cast">'<tt>cast .. to</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]102 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]103 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]104 <li><a href="#i_vaarg">'<tt>vaarg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]105 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]106 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]107 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]108 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]109 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]110 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]111 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
112 <ol>
113 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
114 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
115 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
116 </ol>
117 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]118 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
119 <ol>
120 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
121 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
122 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
123 </ol>
124 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]125 <li><a href="#int_codegen">Code Generator Intrinsics</a>
126 <ol>
127 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
128 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]129 <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]130 <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]131 </ol>
132 </li>
133 <li><a href="#int_os">Operating System Intrinsics</a>
134 <ol>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]135 <li><a href="#i_readport">'<tt>llvm.readport</tt>' Intrinsic</a></li>
136 <li><a href="#i_writeport">'<tt>llvm.writeport</tt>' Intrinsic</a></li>
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]137 <li><a href="#i_readio">'<tt>llvm.readio</tt>' Intrinsic</a></li>
138 <li><a href="#i_writeio">'<tt>llvm.writeio</tt>' Intrinsic</a></li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]139 </ol>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]140 <li><a href="#int_libc">Standard C Library Intrinsics</a>
141 <ol>
142 <li><a href="#i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a></li>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]143 <li><a href="#i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a></li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]144 <li><a href="#i_memset">'<tt>llvm.memset</tt>' Intrinsic</a></li>
Alkis Evlogimenos96853722004-06-12 19:19:14 +0000[diff] [blame]145 <li><a href="#i_isunordered">'<tt>llvm.isunordered</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]146 </ol>
147 </li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]148 <li><a href="#int_count">Bit counting Intrinsics</a>
149 <ol>
150 <li><a href="#int_ctpop">'<tt>llvm.ctpop</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]151 <li><a href="#int_ctlz">'<tt>llvm.ctlz</tt>' Intrinsic </a></li>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]152 <li><a href="#int_cttz">'<tt>llvm.cttz</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]153 </ol>
154 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]155 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]156 </ol>
157 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]158</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]159
160<div class="doc_author">
161 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
162 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]163</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]164
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]165<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]166<div class="doc_section"> <a name="abstract">Abstract </a></div>
167<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]168
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]169<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]170<p>This document is a reference manual for the LLVM assembly language.
171LLVM is an SSA based representation that provides type safety,
172low-level operations, flexibility, and the capability of representing
173'all' high-level languages cleanly. It is the common code
174representation used throughout all phases of the LLVM compilation
175strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]176</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]177
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]178<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]179<div class="doc_section"> <a name="introduction">Introduction</a> </div>
180<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]181
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]182<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]183
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]184<p>The LLVM code representation is designed to be used in three
185different forms: as an in-memory compiler IR, as an on-disk bytecode
186representation (suitable for fast loading by a Just-In-Time compiler),
187and as a human readable assembly language representation. This allows
188LLVM to provide a powerful intermediate representation for efficient
189compiler transformations and analysis, while providing a natural means
190to debug and visualize the transformations. The three different forms
191of LLVM are all equivalent. This document describes the human readable
192representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]193
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]194<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]195while being expressive, typed, and extensible at the same time. It
196aims to be a "universal IR" of sorts, by being at a low enough level
197that high-level ideas may be cleanly mapped to it (similar to how
198microprocessors are "universal IR's", allowing many source languages to
199be mapped to them). By providing type information, LLVM can be used as
200the target of optimizations: for example, through pointer analysis, it
201can be proven that a C automatic variable is never accessed outside of
202the current function... allowing it to be promoted to a simple SSA
203value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]204
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]205</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]206
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]207<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]208<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]209
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]210<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]211
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212<p>It is important to note that this document describes 'well formed'
213LLVM assembly language. There is a difference between what the parser
214accepts and what is considered 'well formed'. For example, the
215following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]216
217<pre>
218 %x = <a href="#i_add">add</a> int 1, %x
219</pre>
220
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]221<p>...because the definition of <tt>%x</tt> does not dominate all of
222its uses. The LLVM infrastructure provides a verification pass that may
223be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]224automatically run by the parser after parsing input assembly and by
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]225the optimizer before it outputs bytecode. The violations pointed out
226by the verifier pass indicate bugs in transformation passes or input to
227the parser.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]228
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]229<!-- Describe the typesetting conventions here. --> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]230
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]231<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]232<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]233<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]234
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]235<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]236
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]237<p>LLVM uses three different forms of identifiers, for different
238purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]239
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]240<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]241 <li>Named values are represented as a string of characters with a '%' prefix.
242 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
243 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
244 Identifiers which require other characters in their names can be surrounded
245 with quotes. In this way, anything except a <tt>"</tt> character can be used
246 in a name.</li>
247
248 <li>Unnamed values are represented as an unsigned numeric value with a '%'
249 prefix. For example, %12, %2, %44.</li>
250
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]251 <li>Constants, which are described in a <a href="#constants">section about
252 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]253</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]254
255<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
256don't need to worry about name clashes with reserved words, and the set of
257reserved words may be expanded in the future without penalty. Additionally,
258unnamed identifiers allow a compiler to quickly come up with a temporary
259variable without having to avoid symbol table conflicts.</p>
260
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]261<p>Reserved words in LLVM are very similar to reserved words in other
262languages. There are keywords for different opcodes ('<tt><a
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]263href="#i_add">add</a></tt>', '<tt><a href="#i_cast">cast</a></tt>', '<tt><a
264href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
265href="#t_void">void</a></tt>', '<tt><a href="#t_uint">uint</a></tt>', etc...),
266and others. These reserved words cannot conflict with variable names, because
267none of them start with a '%' character.</p>
268
269<p>Here is an example of LLVM code to multiply the integer variable
270'<tt>%X</tt>' by 8:</p>
271
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]272<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]273
274<pre>
275 %result = <a href="#i_mul">mul</a> uint %X, 8
276</pre>
277
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]278<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]279
280<pre>
281 %result = <a href="#i_shl">shl</a> uint %X, ubyte 3
282</pre>
283
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]284<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]285
286<pre>
287 <a href="#i_add">add</a> uint %X, %X <i>; yields {uint}:%0</i>
288 <a href="#i_add">add</a> uint %0, %0 <i>; yields {uint}:%1</i>
289 %result = <a href="#i_add">add</a> uint %1, %1
290</pre>
291
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]292<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
293important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]294
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]295<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]296
297 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
298 line.</li>
299
300 <li>Unnamed temporaries are created when the result of a computation is not
301 assigned to a named value.</li>
302
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]303 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]304
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]305</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]306
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]307<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]308demonstrating instructions, we will follow an instruction with a comment that
309defines the type and name of value produced. Comments are shown in italic
310text.</p>
311
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]312</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]313
314<!-- *********************************************************************** -->
315<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
316<!-- *********************************************************************** -->
317
318<!-- ======================================================================= -->
319<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
320</div>
321
322<div class="doc_text">
323
324<p>LLVM programs are composed of "Module"s, each of which is a
325translation unit of the input programs. Each module consists of
326functions, global variables, and symbol table entries. Modules may be
327combined together with the LLVM linker, which merges function (and
328global variable) definitions, resolves forward declarations, and merges
329symbol table entries. Here is an example of the "hello world" module:</p>
330
331<pre><i>; Declare the string constant as a global constant...</i>
332<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
333 href="#globalvars">constant</a> <a href="#t_array">[13 x sbyte]</a> c"hello world\0A\00" <i>; [13 x sbyte]*</i>
334
335<i>; External declaration of the puts function</i>
336<a href="#functionstructure">declare</a> int %puts(sbyte*) <i>; int(sbyte*)* </i>
337
338<i>; Definition of main function</i>
339int %main() { <i>; int()* </i>
340 <i>; Convert [13x sbyte]* to sbyte *...</i>
341 %cast210 = <a
342 href="#i_getelementptr">getelementptr</a> [13 x sbyte]* %.LC0, long 0, long 0 <i>; sbyte*</i>
343
344 <i>; Call puts function to write out the string to stdout...</i>
345 <a
346 href="#i_call">call</a> int %puts(sbyte* %cast210) <i>; int</i>
347 <a
348 href="#i_ret">ret</a> int 0<br>}<br></pre>
349
350<p>This example is made up of a <a href="#globalvars">global variable</a>
351named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
352function, and a <a href="#functionstructure">function definition</a>
353for "<tt>main</tt>".</p>
354
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]355<p>In general, a module is made up of a list of global values,
356where both functions and global variables are global values. Global values are
357represented by a pointer to a memory location (in this case, a pointer to an
358array of char, and a pointer to a function), and have one of the following <a
359href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]360
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]361</div>
362
363<!-- ======================================================================= -->
364<div class="doc_subsection">
365 <a name="linkage">Linkage Types</a>
366</div>
367
368<div class="doc_text">
369
370<p>
371All Global Variables and Functions have one of the following types of linkage:
372</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]373
374<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]375
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]376 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]377
378 <dd>Global values with internal linkage are only directly accessible by
379 objects in the current module. In particular, linking code into a module with
380 an internal global value may cause the internal to be renamed as necessary to
381 avoid collisions. Because the symbol is internal to the module, all
382 references can be updated. This corresponds to the notion of the
383 '<tt>static</tt>' keyword in C, or the idea of "anonymous namespaces" in C++.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]384 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]385
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]386 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]387
388 <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with
389 the twist that linking together two modules defining the same
390 <tt>linkonce</tt> globals will cause one of the globals to be discarded. This
391 is typically used to implement inline functions. Unreferenced
392 <tt>linkonce</tt> globals are allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]393 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]394
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]395 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]396
397 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
398 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
399 used to implement constructs in C such as "<tt>int X;</tt>" at global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]400 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]401
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]402 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]403
404 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
405 pointer to array type. When two global variables with appending linkage are
406 linked together, the two global arrays are appended together. This is the
407 LLVM, typesafe, equivalent of having the system linker append together
408 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]409 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]410
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]411 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]412
413 <dd>If none of the above identifiers are used, the global is externally
414 visible, meaning that it participates in linkage and can be used to resolve
415 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]416 </dd>
417</dl>
418
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]419<p><a name="linkage_external">For example, since the "<tt>.LC0</tt>"
420variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
421variable and was linked with this one, one of the two would be renamed,
422preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
423external (i.e., lacking any linkage declarations), they are accessible
424outside of the current module. It is illegal for a function <i>declaration</i>
425to have any linkage type other than "externally visible".</a></p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]426
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]427</div>
428
429<!-- ======================================================================= -->
430<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]431 <a name="callingconv">Calling Conventions</a>
432</div>
433
434<div class="doc_text">
435
436<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
437and <a href="#i_invoke">invokes</a> can all have an optional calling convention
438specified for the call. The calling convention of any pair of dynamic
439caller/callee must match, or the behavior of the program is undefined. The
440following calling conventions are supported by LLVM, and more may be added in
441the future:</p>
442
443<dl>
444 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
445
446 <dd>This calling convention (the default if no other calling convention is
447 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]448 supports varargs function calls and tolerates some mismatch in the declared
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]449 prototype and implemented declaration of the function (as does normal C).
450 </dd>
451
452 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
453
454 <dd>This calling convention attempts to make calls as fast as possible
455 (e.g. by passing things in registers). This calling convention allows the
456 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]457 without having to conform to an externally specified ABI. Implementations of
458 this convention should allow arbitrary tail call optimization to be supported.
459 This calling convention does not support varargs and requires the prototype of
460 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]461 </dd>
462
463 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
464
465 <dd>This calling convention attempts to make code in the caller as efficient
466 as possible under the assumption that the call is not commonly executed. As
467 such, these calls often preserve all registers so that the call does not break
468 any live ranges in the caller side. This calling convention does not support
469 varargs and requires the prototype of all callees to exactly match the
470 prototype of the function definition.
471 </dd>
472
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]473 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]474
475 <dd>Any calling convention may be specified by number, allowing
476 target-specific calling conventions to be used. Target specific calling
477 conventions start at 64.
478 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]479</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]480
481<p>More calling conventions can be added/defined on an as-needed basis, to
482support pascal conventions or any other well-known target-independent
483convention.</p>
484
485</div>
486
487<!-- ======================================================================= -->
488<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]489 <a name="globalvars">Global Variables</a>
490</div>
491
492<div class="doc_text">
493
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]494<p>Global variables define regions of memory allocated at compilation time
495instead of run-time. Global variables may optionally be initialized. A
496variable may be defined as a global "constant", which indicates that the
497contents of the variable will <b>never</b> be modified (enabling better
498optimization, allowing the global data to be placed in the read-only section of
499an executable, etc). Note that variables that need runtime initialization
500cannot be marked "constant", as there is a store to the variable.</p>
501
502<p>
503LLVM explicitly allows <em>declarations</em> of global variables to be marked
504constant, even if the final definition of the global is not. This capability
505can be used to enable slightly better optimization of the program, but requires
506the language definition to guarantee that optimizations based on the
507'constantness' are valid for the translation units that do not include the
508definition.
509</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]510
511<p>As SSA values, global variables define pointer values that are in
512scope (i.e. they dominate) all basic blocks in the program. Global
513variables always define a pointer to their "content" type because they
514describe a region of memory, and all memory objects in LLVM are
515accessed through pointers.</p>
516
517</div>
518
519
520<!-- ======================================================================= -->
521<div class="doc_subsection">
522 <a name="functionstructure">Functions</a>
523</div>
524
525<div class="doc_text">
526
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]527<p>LLVM function definitions consist of an optional <a href="#linkage">linkage
528type</a>, an optional <a href="#callingconv">calling convention</a>, a return
529type, a function name, a (possibly empty) argument list, an opening curly brace,
530a list of basic blocks, and a closing curly brace. LLVM function declarations
531are defined with the "<tt>declare</tt>" keyword, an optional <a
532href="#callingconv">calling convention</a>, a return type, a function name, and
533a possibly empty list of arguments.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]534
535<p>A function definition contains a list of basic blocks, forming the CFG for
536the function. Each basic block may optionally start with a label (giving the
537basic block a symbol table entry), contains a list of instructions, and ends
538with a <a href="#terminators">terminator</a> instruction (such as a branch or
539function return).</p>
540
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]541<p>The first basic block in a program is special in two ways: it is immediately
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]542executed on entrance to the function, and it is not allowed to have predecessor
543basic blocks (i.e. there can not be any branches to the entry block of a
544function). Because the block can have no predecessors, it also cannot have any
545<a href="#i_phi">PHI nodes</a>.</p>
546
547<p>LLVM functions are identified by their name and type signature. Hence, two
548functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]549considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]550appropriately.</p>
551
552</div>
553
554
555
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]556<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]557<div class="doc_section"> <a name="typesystem">Type System</a> </div>
558<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]559
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]560<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]561
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]562<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]563intermediate representation. Being typed enables a number of
564optimizations to be performed on the IR directly, without having to do
565extra analyses on the side before the transformation. A strong type
566system makes it easier to read the generated code and enables novel
567analyses and transformations that are not feasible to perform on normal
568three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]569
570</div>
571
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]572<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]573<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]574<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]575<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]576system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]577
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]578<table class="layout">
579 <tr class="layout">
580 <td class="left">
581 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]582 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]583 <tr><th>Type</th><th>Description</th></tr>
584 <tr><td><tt>void</tt></td><td>No value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]585 <tr><td><tt>ubyte</tt></td><td>Unsigned 8-bit value</td></tr>
586 <tr><td><tt>ushort</tt></td><td>Unsigned 16-bit value</td></tr>
587 <tr><td><tt>uint</tt></td><td>Unsigned 32-bit value</td></tr>
588 <tr><td><tt>ulong</tt></td><td>Unsigned 64-bit value</td></tr>
589 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]590 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]591 </tbody>
592 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]593 </td>
594 <td class="right">
595 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]596 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]597 <tr><th>Type</th><th>Description</th></tr>
598 <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]599 <tr><td><tt>sbyte</tt></td><td>Signed 8-bit value</td></tr>
600 <tr><td><tt>short</tt></td><td>Signed 16-bit value</td></tr>
601 <tr><td><tt>int</tt></td><td>Signed 32-bit value</td></tr>
602 <tr><td><tt>long</tt></td><td>Signed 64-bit value</td></tr>
603 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]604 </tbody>
605 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]606 </td>
607 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]608</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]609</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]610
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]611<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]612<div class="doc_subsubsection"> <a name="t_classifications">Type
613Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]614<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]615<p>These different primitive types fall into a few useful
616classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]617
618<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]619 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]620 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]621 <tr>
622 <td><a name="t_signed">signed</a></td>
623 <td><tt>sbyte, short, int, long, float, double</tt></td>
624 </tr>
625 <tr>
626 <td><a name="t_unsigned">unsigned</a></td>
627 <td><tt>ubyte, ushort, uint, ulong</tt></td>
628 </tr>
629 <tr>
630 <td><a name="t_integer">integer</a></td>
631 <td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td>
632 </tr>
633 <tr>
634 <td><a name="t_integral">integral</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]635 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long</tt>
636 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]637 </tr>
638 <tr>
639 <td><a name="t_floating">floating point</a></td>
640 <td><tt>float, double</tt></td>
641 </tr>
642 <tr>
643 <td><a name="t_firstclass">first class</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]644 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long,<br>
645 float, double, <a href="#t_pointer">pointer</a>,
646 <a href="#t_packed">packed</a></tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]647 </tr>
648 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]649</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]650
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]651<p>The <a href="#t_firstclass">first class</a> types are perhaps the
652most important. Values of these types are the only ones which can be
653produced by instructions, passed as arguments, or used as operands to
654instructions. This means that all structures and arrays must be
655manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]656</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]657
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]658<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]659<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]660
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]661<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]662
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]663<p>The real power in LLVM comes from the derived types in the system.
664This is what allows a programmer to represent arrays, functions,
665pointers, and other useful types. Note that these derived types may be
666recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]667
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]668</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]669
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]670<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]671<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]672
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]673<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]674
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]675<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]676
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]677<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]678sequentially in memory. The array type requires a size (number of
679elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]680
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]681<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]682
683<pre>
684 [&lt;# elements&gt; x &lt;elementtype&gt;]
685</pre>
686
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]687<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]688be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]689
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]690<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]691<table class="layout">
692 <tr class="layout">
693 <td class="left">
694 <tt>[40 x int ]</tt><br/>
695 <tt>[41 x int ]</tt><br/>
696 <tt>[40 x uint]</tt><br/>
697 </td>
698 <td class="left">
699 Array of 40 integer values.<br/>
700 Array of 41 integer values.<br/>
701 Array of 40 unsigned integer values.<br/>
702 </td>
703 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]704</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]705<p>Here are some examples of multidimensional arrays:</p>
706<table class="layout">
707 <tr class="layout">
708 <td class="left">
709 <tt>[3 x [4 x int]]</tt><br/>
710 <tt>[12 x [10 x float]]</tt><br/>
711 <tt>[2 x [3 x [4 x uint]]]</tt><br/>
712 </td>
713 <td class="left">
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]714 3x4 array of integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]715 12x10 array of single precision floating point values.<br/>
716 2x3x4 array of unsigned integer values.<br/>
717 </td>
718 </tr>
719</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]720</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]721
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]722<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]723<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]724<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]725<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]726<p>The function type can be thought of as a function signature. It
727consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]728Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]729(which are structures of pointers to functions), for indirect function
730calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]731<p>
732The return type of a function type cannot be an aggregate type.
733</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]734<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]735<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]736<p>Where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
737specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]738which indicates that the function takes a variable number of arguments.
739Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]740 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]741<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]742<table class="layout">
743 <tr class="layout">
744 <td class="left">
745 <tt>int (int)</tt> <br/>
746 <tt>float (int, int *) *</tt><br/>
747 <tt>int (sbyte *, ...)</tt><br/>
748 </td>
749 <td class="left">
750 function taking an <tt>int</tt>, returning an <tt>int</tt><br/>
751 <a href="#t_pointer">Pointer</a> to a function that takes an
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]752 <tt>int</tt> and a <a href="#t_pointer">pointer</a> to <tt>int</tt>,
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]753 returning <tt>float</tt>.<br/>
754 A vararg function that takes at least one <a href="#t_pointer">pointer</a>
755 to <tt>sbyte</tt> (signed char in C), which returns an integer. This is
756 the signature for <tt>printf</tt> in LLVM.<br/>
757 </td>
758 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]759</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]760
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]761</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]762<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]763<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]764<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]765<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]766<p>The structure type is used to represent a collection of data members
767together in memory. The packing of the field types is defined to match
768the ABI of the underlying processor. The elements of a structure may
769be any type that has a size.</p>
770<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
771and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
772field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
773instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]774<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]775<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]776<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]777<table class="layout">
778 <tr class="layout">
779 <td class="left">
780 <tt>{ int, int, int }</tt><br/>
781 <tt>{ float, int (int) * }</tt><br/>
782 </td>
783 <td class="left">
784 a triple of three <tt>int</tt> values<br/>
785 A pair, where the first element is a <tt>float</tt> and the second element
786 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
787 that takes an <tt>int</tt>, returning an <tt>int</tt>.<br/>
788 </td>
789 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]790</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]791</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]792
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="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]795<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]796<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]797<p>As in many languages, the pointer type represents a pointer or
798reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]799<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]800<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]801<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]802<table class="layout">
803 <tr class="layout">
804 <td class="left">
805 <tt>[4x int]*</tt><br/>
806 <tt>int (int *) *</tt><br/>
807 </td>
808 <td class="left">
809 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
810 four <tt>int</tt> values<br/>
811 A <a href="#t_pointer">pointer</a> to a <a
Chris Lattnera977c482005-02-19 02:22:14 +0000[diff] [blame]812 href="#t_function">function</a> that takes an <tt>int*</tt>, returning an
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]813 <tt>int</tt>.<br/>
814 </td>
815 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]816</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]817</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]818
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]819<!-- _______________________________________________________________________ -->
820<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]821<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]822
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]823<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]824
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]825<p>A packed type is a simple derived type that represents a vector
826of elements. Packed types are used when multiple primitive data
827are operated in parallel using a single instruction (SIMD).
828A packed type requires a size (number of
829elements) and an underlying primitive data type. Packed types are
830considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]831
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]832<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]833
834<pre>
835 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
836</pre>
837
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]838<p>The number of elements is a constant integer value; elementtype may
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]839be any integral or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]840
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]841<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]842
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]843<table class="layout">
844 <tr class="layout">
845 <td class="left">
846 <tt>&lt;4 x int&gt;</tt><br/>
847 <tt>&lt;8 x float&gt;</tt><br/>
848 <tt>&lt;2 x uint&gt;</tt><br/>
849 </td>
850 <td class="left">
851 Packed vector of 4 integer values.<br/>
852 Packed vector of 8 floating-point values.<br/>
853 Packed vector of 2 unsigned integer values.<br/>
854 </td>
855 </tr>
856</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]857</div>
858
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]859<!-- _______________________________________________________________________ -->
860<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
861<div class="doc_text">
862
863<h5>Overview:</h5>
864
865<p>Opaque types are used to represent unknown types in the system. This
866corresponds (for example) to the C notion of a foward declared structure type.
867In LLVM, opaque types can eventually be resolved to any type (not just a
868structure type).</p>
869
870<h5>Syntax:</h5>
871
872<pre>
873 opaque
874</pre>
875
876<h5>Examples:</h5>
877
878<table class="layout">
879 <tr class="layout">
880 <td class="left">
881 <tt>opaque</tt>
882 </td>
883 <td class="left">
884 An opaque type.<br/>
885 </td>
886 </tr>
887</table>
888</div>
889
890
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]891<!-- *********************************************************************** -->
892<div class="doc_section"> <a name="constants">Constants</a> </div>
893<!-- *********************************************************************** -->
894
895<div class="doc_text">
896
897<p>LLVM has several different basic types of constants. This section describes
898them all and their syntax.</p>
899
900</div>
901
902<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]903<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]904
905<div class="doc_text">
906
907<dl>
908 <dt><b>Boolean constants</b></dt>
909
910 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
911 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
912 </dd>
913
914 <dt><b>Integer constants</b></dt>
915
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]916 <dd>Standard integers (such as '4') are constants of the <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]917 href="#t_integer">integer</a> type. Negative numbers may be used with signed
918 integer types.
919 </dd>
920
921 <dt><b>Floating point constants</b></dt>
922
923 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
924 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]925 notation (see below). Floating point constants must have a <a
926 href="#t_floating">floating point</a> type. </dd>
927
928 <dt><b>Null pointer constants</b></dt>
929
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]930 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]931 and must be of <a href="#t_pointer">pointer type</a>.</dd>
932
933</dl>
934
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]935<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]936of floating point constants. For example, the form '<tt>double
9370x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
9384.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]939(and the only time that they are generated by the disassembler) is when a
940floating point constant must be emitted but it cannot be represented as a
941decimal floating point number. For example, NaN's, infinities, and other
942special values are represented in their IEEE hexadecimal format so that
943assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]944
945</div>
946
947<!-- ======================================================================= -->
948<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
949</div>
950
951<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]952<p>Aggregate constants arise from aggregation of simple constants
953and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]954
955<dl>
956 <dt><b>Structure constants</b></dt>
957
958 <dd>Structure constants are represented with notation similar to structure
959 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]960 (<tt>{}</tt>)). For example: "<tt>{ int 4, float 17.0, int* %G }</tt>",
961 where "<tt>%G</tt>" is declared as "<tt>%G = external global int</tt>". Structure constants
962 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]963 types of elements must match those specified by the type.
964 </dd>
965
966 <dt><b>Array constants</b></dt>
967
968 <dd>Array constants are represented with notation similar to array type
969 definitions (a comma separated list of elements, surrounded by square brackets
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]970 (<tt>[]</tt>)). For example: "<tt>[ int 42, int 11, int 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]971 constants must have <a href="#t_array">array type</a>, and the number and
972 types of elements must match those specified by the type.
973 </dd>
974
975 <dt><b>Packed constants</b></dt>
976
977 <dd>Packed constants are represented with notation similar to packed type
978 definitions (a comma separated list of elements, surrounded by
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]979 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; int 42,
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]980 int 11, int 74, int 100 &gt;</tt>". Packed constants must have <a
981 href="#t_packed">packed type</a>, and the number and types of elements must
982 match those specified by the type.
983 </dd>
984
985 <dt><b>Zero initialization</b></dt>
986
987 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
988 value to zero of <em>any</em> type, including scalar and aggregate types.
989 This is often used to avoid having to print large zero initializers (e.g. for
990 large arrays), and is always exactly equivalent to using explicit zero
991 initializers.
992 </dd>
993</dl>
994
995</div>
996
997<!-- ======================================================================= -->
998<div class="doc_subsection">
999 <a name="globalconstants">Global Variable and Function Addresses</a>
1000</div>
1001
1002<div class="doc_text">
1003
1004<p>The addresses of <a href="#globalvars">global variables</a> and <a
1005href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1006constants. These constants are explicitly referenced when the <a
1007href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1008href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1009file:</p>
1010
1011<pre>
1012 %X = global int 17
1013 %Y = global int 42
1014 %Z = global [2 x int*] [ int* %X, int* %Y ]
1015</pre>
1016
1017</div>
1018
1019<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1020<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1021<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1022 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1023 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1024 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1025
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1026 <p>Undefined values indicate to the compiler that the program is well defined
1027 no matter what value is used, giving the compiler more freedom to optimize.
1028 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1029</div>
1030
1031<!-- ======================================================================= -->
1032<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1033</div>
1034
1035<div class="doc_text">
1036
1037<p>Constant expressions are used to allow expressions involving other constants
1038to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1039href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1040that does not have side effects (e.g. load and call are not supported). The
1041following is the syntax for constant expressions:</p>
1042
1043<dl>
1044 <dt><b><tt>cast ( CST to TYPE )</tt></b></dt>
1045
1046 <dd>Cast a constant to another type.</dd>
1047
1048 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1049
1050 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1051 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1052 instruction, the index list may have zero or more indexes, which are required
1053 to make sense for the type of "CSTPTR".</dd>
1054
1055 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1056
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1057 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1058 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1059 binary</a> operations. The constraints on operands are the same as those for
1060 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1061 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1062</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1063</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1064
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1065<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1066<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1067<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1068
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1069<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1070
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1071<p>The LLVM instruction set consists of several different
1072classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1073instructions</a>, <a href="#binaryops">binary instructions</a>,
1074<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1075 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1076instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1077
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1078</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1079
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1080<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1081<div class="doc_subsection"> <a name="terminators">Terminator
1082Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1083
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1084<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1085
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1086<p>As mentioned <a href="#functionstructure">previously</a>, every
1087basic block in a program ends with a "Terminator" instruction, which
1088indicates which block should be executed after the current block is
1089finished. These terminator instructions typically yield a '<tt>void</tt>'
1090value: they produce control flow, not values (the one exception being
1091the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1092<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1093 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1094instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1095the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1096 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1097 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1098
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1099</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1100
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1101<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1102<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1103Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1104<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1105<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1106<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]1107 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1108</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1109<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1110<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1111value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1112<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1113returns a value and then causes control flow, and one that just causes
1114control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1115<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1116<p>The '<tt>ret</tt>' instruction may return any '<a
1117 href="#t_firstclass">first class</a>' type. Notice that a function is
1118not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1119instruction inside of the function that returns a value that does not
1120match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1121<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1122<p>When the '<tt>ret</tt>' instruction is executed, control flow
1123returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1124 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1125the instruction after the call. If the caller was an "<a
1126 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1127at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1128returns a value, that value shall set the call or invoke instruction's
1129return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1130<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1131<pre> ret int 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1132 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1133</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1134</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1135<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1136<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1137<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1138<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1139<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]1140</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1141<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1142<p>The '<tt>br</tt>' instruction is used to cause control flow to
1143transfer to a different basic block in the current function. There are
1144two forms of this instruction, corresponding to a conditional branch
1145and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1146<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1147<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1148single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1149unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1150value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1151<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1152<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1153argument is evaluated. If the value is <tt>true</tt>, control flows
1154to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1155control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1156<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1157<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
1158 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]1159</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1160<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1161<div class="doc_subsubsection">
1162 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1163</div>
1164
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1165<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1166<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1167
1168<pre>
1169 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1170</pre>
1171
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1172<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1173
1174<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1175several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1176instruction, allowing a branch to occur to one of many possible
1177destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1178
1179
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1180<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1181
1182<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1183comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1184an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1185table is not allowed to contain duplicate constant entries.</p>
1186
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1187<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1188
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1189<p>The <tt>switch</tt> instruction specifies a table of values and
1190destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1191table is searched for the given value. If the value is found, control flow is
1192transfered to the corresponding destination; otherwise, control flow is
1193transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1194
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1195<h5>Implementation:</h5>
1196
1197<p>Depending on properties of the target machine and the particular
1198<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1199ways. For example, it could be generated as a series of chained conditional
1200branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1201
1202<h5>Example:</h5>
1203
1204<pre>
1205 <i>; Emulate a conditional br instruction</i>
1206 %Val = <a href="#i_cast">cast</a> bool %value to int
1207 switch int %Val, label %truedest [int 0, label %falsedest ]
1208
1209 <i>; Emulate an unconditional br instruction</i>
1210 switch uint 0, label %dest [ ]
1211
1212 <i>; Implement a jump table:</i>
1213 switch uint %val, label %otherwise [ uint 0, label %onzero
1214 uint 1, label %onone
1215 uint 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1216</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1217</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1218
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1219<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1220<div class="doc_subsubsection">
1221 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1222</div>
1223
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1224<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1225
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1226<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1227
1228<pre>
1229 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] &lt;ptr to function ty&gt; %&lt;function ptr val&gt;(&lt;function args&gt;)
1230 to label &lt;normal label&gt; except label &lt;exception label&gt;
1231</pre>
1232
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1233<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1234
1235<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1236function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1237'<tt>normal</tt>' label or the
1238'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1239"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1240"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1241href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1242continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1243
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1244<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1245
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1246<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1247
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1248<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1249 <li>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1250 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1251 convention</a> the call should use. If none is specified, the call defaults
1252 to using C calling conventions.
1253 </li>
1254 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1255 function value being invoked. In most cases, this is a direct function
1256 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1257 an arbitrary pointer to function value.
1258 </li>
1259
1260 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1261 function to be invoked. </li>
1262
1263 <li>'<tt>function args</tt>': argument list whose types match the function
1264 signature argument types. If the function signature indicates the function
1265 accepts a variable number of arguments, the extra arguments can be
1266 specified. </li>
1267
1268 <li>'<tt>normal label</tt>': the label reached when the called function
1269 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1270
1271 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1272 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1273
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1274</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1275
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1276<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1277
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1278<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1279href="#i_call">call</a></tt>' instruction in most regards. The primary
1280difference is that it establishes an association with a label, which is used by
1281the runtime library to unwind the stack.</p>
1282
1283<p>This instruction is used in languages with destructors to ensure that proper
1284cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1285exception. Additionally, this is important for implementation of
1286'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1287
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1288<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1289<pre>
1290 %retval = invoke int %Test(int 15) to label %Continue
1291 except label %TestCleanup <i>; {int}:retval set</i>
1292 %retval = invoke <a href="#callingconv">coldcc</a> int %Test(int 15) to label %Continue
1293 except label %TestCleanup <i>; {int}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1294</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1295</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1296
1297
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1298<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1299
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1300<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1301Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1302
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1303<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1304
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1305<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1306<pre>
1307 unwind
1308</pre>
1309
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1310<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1311
1312<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1313at the first callee in the dynamic call stack which used an <a
1314href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1315primarily used to implement exception handling.</p>
1316
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1317<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1318
1319<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1320immediately halt. The dynamic call stack is then searched for the first <a
1321href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1322execution continues at the "exceptional" destination block specified by the
1323<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1324dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1325</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1326
1327<!-- _______________________________________________________________________ -->
1328
1329<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1330Instruction</a> </div>
1331
1332<div class="doc_text">
1333
1334<h5>Syntax:</h5>
1335<pre>
1336 unreachable
1337</pre>
1338
1339<h5>Overview:</h5>
1340
1341<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1342instruction is used to inform the optimizer that a particular portion of the
1343code is not reachable. This can be used to indicate that the code after a
1344no-return function cannot be reached, and other facts.</p>
1345
1346<h5>Semantics:</h5>
1347
1348<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1349</div>
1350
1351
1352
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_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1355<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1356<p>Binary operators are used to do most of the computation in a
1357program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1358produce a single value. The operands might represent
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1359multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1360The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1361necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1362<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1363</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1364<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1365<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1366Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1367<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1368<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1369<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]1370</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1371<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1372<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1373<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1374<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1375 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1376 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1377Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1378<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1379<p>The value produced is the integer or floating point sum of the two
1380operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1381<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1382<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]1383</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1384</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1385<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1386<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1387Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1388<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1389<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1390<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]1391</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1392<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1393<p>The '<tt>sub</tt>' instruction returns the difference of its two
1394operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1395<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1396instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1397<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1398<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1399 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1400values.
1401This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1402Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1403<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1404<p>The value produced is the integer or floating point difference of
1405the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1406<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1407<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]1408 &lt;result&gt; = sub int 0, %val <i>; yields {int}:result = -%var</i>
1409</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1410</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1411<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1412<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1413Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1414<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1415<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1416<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]1417</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1418<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1419<p>The '<tt>mul</tt>' instruction returns the product of its two
1420operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1421<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1422<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1423 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1424values.
1425This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1426Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1427<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1428<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1429two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1430<p>There is no signed vs unsigned multiplication. The appropriate
1431action is taken based on the type of the operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1432<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1433<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]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_div">'<tt>div</tt>'
1438Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1439<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1440<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1441<pre> &lt;result&gt; = div &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1442</pre>
1443<h5>Overview:</h5>
1444<p>The '<tt>div</tt>' instruction returns the quotient of its two
1445operands.</p>
1446<h5>Arguments:</h5>
1447<p>The two arguments to the '<tt>div</tt>' instruction must be either <a
1448 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1449values.
1450This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1451Both arguments must have identical types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1452<h5>Semantics:</h5>
1453<p>The value produced is the integer or floating point quotient of the
1454two operands.</p>
1455<h5>Example:</h5>
1456<pre> &lt;result&gt; = div int 4, %var <i>; yields {int}:result = 4 / %var</i>
1457</pre>
1458</div>
1459<!-- _______________________________________________________________________ -->
1460<div class="doc_subsubsection"> <a name="i_rem">'<tt>rem</tt>'
1461Instruction</a> </div>
1462<div class="doc_text">
1463<h5>Syntax:</h5>
1464<pre> &lt;result&gt; = rem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1465</pre>
1466<h5>Overview:</h5>
1467<p>The '<tt>rem</tt>' instruction returns the remainder from the
1468division of its two operands.</p>
1469<h5>Arguments:</h5>
1470<p>The two arguments to the '<tt>rem</tt>' instruction must be either <a
1471 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1472values.
1473This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1474Both arguments must have identical types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1475<h5>Semantics:</h5>
1476<p>This returns the <i>remainder</i> of a division (where the result
1477has the same sign as the divisor), not the <i>modulus</i> (where the
1478result has the same sign as the dividend) of a value. For more
1479information about the difference, see: <a
1480 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1481Math Forum</a>.</p>
1482<h5>Example:</h5>
1483<pre> &lt;result&gt; = rem int 4, %var <i>; yields {int}:result = 4 % %var</i>
1484</pre>
1485</div>
1486<!-- _______________________________________________________________________ -->
1487<div class="doc_subsubsection"> <a name="i_setcc">'<tt>set<i>cc</i></tt>'
1488Instructions</a> </div>
1489<div class="doc_text">
1490<h5>Syntax:</h5>
1491<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]1492 &lt;result&gt; = setne &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1493 &lt;result&gt; = setlt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1494 &lt;result&gt; = setgt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1495 &lt;result&gt; = setle &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1496 &lt;result&gt; = setge &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1497</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1498<h5>Overview:</h5>
1499<p>The '<tt>set<i>cc</i></tt>' family of instructions returns a boolean
1500value based on a comparison of their two operands.</p>
1501<h5>Arguments:</h5>
1502<p>The two arguments to the '<tt>set<i>cc</i></tt>' instructions must
1503be of <a href="#t_firstclass">first class</a> type (it is not possible
1504to compare '<tt>label</tt>'s, '<tt>array</tt>'s, '<tt>structure</tt>'
1505or '<tt>void</tt>' values, etc...). Both arguments must have identical
1506types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1507<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1508<p>The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1509value if both operands are equal.<br>
1510The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1511value if both operands are unequal.<br>
1512The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1513value if the first operand is less than the second operand.<br>
1514The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1515value if the first operand is greater than the second operand.<br>
1516The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1517value if the first operand is less than or equal to the second operand.<br>
1518The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1519value if the first operand is greater than or equal to the second
1520operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1521<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1522<pre> &lt;result&gt; = seteq int 4, 5 <i>; yields {bool}:result = false</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1523 &lt;result&gt; = setne float 4, 5 <i>; yields {bool}:result = true</i>
1524 &lt;result&gt; = setlt uint 4, 5 <i>; yields {bool}:result = true</i>
1525 &lt;result&gt; = setgt sbyte 4, 5 <i>; yields {bool}:result = false</i>
1526 &lt;result&gt; = setle sbyte 4, 5 <i>; yields {bool}:result = true</i>
1527 &lt;result&gt; = setge sbyte 4, 5 <i>; yields {bool}:result = false</i>
1528</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1529</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1530<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1531<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1532Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1533<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1534<p>Bitwise binary operators are used to do various forms of
1535bit-twiddling in a program. They are generally very efficient
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1536instructions and can commonly be strength reduced from other
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1537instructions. They require two operands, execute an operation on them,
1538and produce a single value. The resulting value of the bitwise binary
1539operators is always the same type as its first operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1540</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1541<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1542<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1543Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1544<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1545<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1546<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]1547</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1548<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1549<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1550its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1551<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1552<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1553 href="#t_integral">integral</a> values. Both arguments must have
1554identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1555<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1556<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1557<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1558<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1559<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1560 <tbody>
1561 <tr>
1562 <td>In0</td>
1563 <td>In1</td>
1564 <td>Out</td>
1565 </tr>
1566 <tr>
1567 <td>0</td>
1568 <td>0</td>
1569 <td>0</td>
1570 </tr>
1571 <tr>
1572 <td>0</td>
1573 <td>1</td>
1574 <td>0</td>
1575 </tr>
1576 <tr>
1577 <td>1</td>
1578 <td>0</td>
1579 <td>0</td>
1580 </tr>
1581 <tr>
1582 <td>1</td>
1583 <td>1</td>
1584 <td>1</td>
1585 </tr>
1586 </tbody>
1587</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1588</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1589<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1590<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]1591 &lt;result&gt; = and int 15, 40 <i>; yields {int}:result = 8</i>
1592 &lt;result&gt; = and int 4, 8 <i>; yields {int}:result = 0</i>
1593</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1594</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1595<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1596<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1597<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1598<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1599<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]1600</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1601<h5>Overview:</h5>
1602<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1603or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1604<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1605<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1606 href="#t_integral">integral</a> values. Both arguments must have
1607identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1608<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1609<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1610<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1611<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1612<table border="1" cellspacing="0" cellpadding="4">
1613 <tbody>
1614 <tr>
1615 <td>In0</td>
1616 <td>In1</td>
1617 <td>Out</td>
1618 </tr>
1619 <tr>
1620 <td>0</td>
1621 <td>0</td>
1622 <td>0</td>
1623 </tr>
1624 <tr>
1625 <td>0</td>
1626 <td>1</td>
1627 <td>1</td>
1628 </tr>
1629 <tr>
1630 <td>1</td>
1631 <td>0</td>
1632 <td>1</td>
1633 </tr>
1634 <tr>
1635 <td>1</td>
1636 <td>1</td>
1637 <td>1</td>
1638 </tr>
1639 </tbody>
1640</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1641</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1642<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1643<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]1644 &lt;result&gt; = or int 15, 40 <i>; yields {int}:result = 47</i>
1645 &lt;result&gt; = or int 4, 8 <i>; yields {int}:result = 12</i>
1646</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1647</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1648<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1649<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
1650Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1651<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1652<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1653<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]1654</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1655<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1656<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
1657or of its two operands. The <tt>xor</tt> is used to implement the
1658"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1659<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1660<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1661 href="#t_integral">integral</a> values. Both arguments must have
1662identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1663<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1664<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1665<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1666<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1667<table border="1" cellspacing="0" cellpadding="4">
1668 <tbody>
1669 <tr>
1670 <td>In0</td>
1671 <td>In1</td>
1672 <td>Out</td>
1673 </tr>
1674 <tr>
1675 <td>0</td>
1676 <td>0</td>
1677 <td>0</td>
1678 </tr>
1679 <tr>
1680 <td>0</td>
1681 <td>1</td>
1682 <td>1</td>
1683 </tr>
1684 <tr>
1685 <td>1</td>
1686 <td>0</td>
1687 <td>1</td>
1688 </tr>
1689 <tr>
1690 <td>1</td>
1691 <td>1</td>
1692 <td>0</td>
1693 </tr>
1694 </tbody>
1695</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1696</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1697<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1698<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1699<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]1700 &lt;result&gt; = xor int 15, 40 <i>; yields {int}:result = 39</i>
1701 &lt;result&gt; = xor int 4, 8 <i>; yields {int}:result = 12</i>
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1702 &lt;result&gt; = xor int %V, -1 <i>; yields {int}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1703</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1704</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1705<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1706<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
1707Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1708<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1709<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1710<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]1711</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1712<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1713<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
1714the left a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1715<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1716<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1717 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1718type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1719<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1720<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]1721<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1722<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]1723 &lt;result&gt; = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
1724 &lt;result&gt; = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
1725</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1726</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1727<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1728<div class="doc_subsubsection"> <a name="i_shr">'<tt>shr</tt>'
1729Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1730<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1731<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1732<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]1733</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1734<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1735<p>The '<tt>shr</tt>' instruction returns the first operand shifted to
1736the right a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1737<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1738<p>The first argument to the '<tt>shr</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1739 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1740type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1741<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1742<p>If the first argument is a <a href="#t_signed">signed</a> type, the
1743most significant bit is duplicated in the newly free'd bit positions.
1744If the first argument is unsigned, zero bits shall fill the empty
1745positions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1746<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1747<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]1748 &lt;result&gt; = shr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1749 &lt;result&gt; = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
Chris Lattner8c6bb902003-06-18 21:30:51 +0000[diff] [blame]1750 &lt;result&gt; = shr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i>
1751 &lt;result&gt; = shr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1752</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1753</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1754<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1755<div class="doc_subsection"> <a name="memoryops">Memory Access
1756Operations</a></div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1757<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1758<p>A key design point of an SSA-based representation is how it
1759represents memory. In LLVM, no memory locations are in SSA form, which
1760makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1761allocate, and free memory in LLVM.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1762</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1763<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1764<div class="doc_subsubsection"> <a name="i_malloc">'<tt>malloc</tt>'
1765Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1766<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1767<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1768<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]1769 &lt;result&gt; = malloc &lt;type&gt; <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1770</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1771<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1772<p>The '<tt>malloc</tt>' instruction allocates memory from the system
1773heap and returns a pointer to it.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1774<h5>Arguments:</h5>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]1775<p>The '<tt>malloc</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
1776bytes of memory from the operating system and returns a pointer of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1777appropriate type to the program. The second form of the instruction is
1778a shorter version of the first instruction that defaults to allocating
1779one element.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1780<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1781<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1782<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
1783a pointer is returned.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1784<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1785<pre> %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1786
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1787 %size = <a
1788 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]1789 %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i>
1790 %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1791</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1792</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1793<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1794<div class="doc_subsubsection"> <a name="i_free">'<tt>free</tt>'
1795Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1796<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1797<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1798<pre> free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1799</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1800<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1801<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1802memory heap to be reallocated in the future.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1803<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1804<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1805<p>'<tt>value</tt>' shall be a pointer value that points to a value
1806that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
1807instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1808<h5>Semantics:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1809<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1810after this instruction executes.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1811<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1812<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]1813 free [4 x ubyte]* %array
1814</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1815</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1816<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1817<div class="doc_subsubsection"> <a name="i_alloca">'<tt>alloca</tt>'
1818Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1819<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1820<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1821<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]1822 &lt;result&gt; = alloca &lt;type&gt; <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1823</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1824<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1825<p>The '<tt>alloca</tt>' instruction allocates memory on the current
1826stack frame of the procedure that is live until the current function
1827returns to its caller.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1828<h5>Arguments:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1829<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1830bytes of memory on the runtime stack, returning a pointer of the
1831appropriate type to the program. The second form of the instruction is
1832a shorter version of the first that defaults to allocating one element.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1833<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1834<h5>Semantics:</h5>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1835<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1836memory is automatically released when the function returns. The '<tt>alloca</tt>'
1837instruction is commonly used to represent automatic variables that must
1838have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]1839 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1840instructions), the memory is reclaimed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1841<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1842<pre> %ptr = alloca int <i>; yields {int*}:ptr</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1843 %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1844</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1845</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1846<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1847<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
1848Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1849<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1850<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1851<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]1852<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1853<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1854<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1855<p>The argument to the '<tt>load</tt>' instruction specifies the memory
1856address to load from. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]1857 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1858marked as <tt>volatile</tt> then the optimizer is not allowed to modify
1859the number or order of execution of this <tt>load</tt> with other
1860volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
1861instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1862<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1863<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1864<h5>Examples:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1865<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
1866 <a
1867 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1868 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
1869</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1870</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1871<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1872<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
1873Instruction</a> </div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1874<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1875<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]1876 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]1877</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1878<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1879<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1880<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1881<p>There are two arguments to the '<tt>store</tt>' instruction: a value
1882to store and an address to store it into. The type of the '<tt>&lt;pointer&gt;</tt>'
1883operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1884operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1885optimizer is not allowed to modify the number or order of execution of
1886this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
1887 href="#i_store">store</a></tt> instructions.</p>
1888<h5>Semantics:</h5>
1889<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
1890at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1891<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1892<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
1893 <a
1894 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1895 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
1896</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1897<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1898<div class="doc_subsubsection">
1899 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
1900</div>
1901
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1902<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1903<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1904<pre>
1905 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
1906</pre>
1907
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1908<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1909
1910<p>
1911The '<tt>getelementptr</tt>' instruction is used to get the address of a
1912subelement of an aggregate data structure.</p>
1913
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1914<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1915
1916<p>This instruction takes a list of integer constants that indicate what
1917elements of the aggregate object to index to. The actual types of the arguments
1918provided depend on the type of the first pointer argument. The
1919'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]1920levels of a structure or to a specific index in an array. When indexing into a
1921structure, only <tt>uint</tt>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1922integer constants are allowed. When indexing into an array or pointer,
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1923<tt>int</tt> and <tt>long</tt> indexes are allowed of any sign.</p>
1924
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1925<p>For example, let's consider a C code fragment and how it gets
1926compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1927
1928<pre>
1929 struct RT {
1930 char A;
1931 int B[10][20];
1932 char C;
1933 };
1934 struct ST {
1935 int X;
1936 double Y;
1937 struct RT Z;
1938 };
1939
1940 int *foo(struct ST *s) {
1941 return &amp;s[1].Z.B[5][13];
1942 }
1943</pre>
1944
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1945<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1946
1947<pre>
1948 %RT = type { sbyte, [10 x [20 x int]], sbyte }
1949 %ST = type { int, double, %RT }
1950
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]1951 implementation
1952
1953 int* %foo(%ST* %s) {
1954 entry:
1955 %reg = getelementptr %ST* %s, int 1, uint 2, uint 1, int 5, int 13
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1956 ret int* %reg
1957 }
1958</pre>
1959
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1960<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1961
1962<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1963on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]1964and <a href="#t_array">array</a> types require <tt>uint</tt>, <tt>int</tt>,
1965<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]1966types require <tt>uint</tt> <b>constants</b>.</p>
1967
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1968<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]1969type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT
1970}</tt>' type, a structure. The second index indexes into the third element of
1971the structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]],
1972sbyte }</tt>' type, another structure. The third index indexes into the second
1973element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an
1974array. The two dimensions of the array are subscripted into, yielding an
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]1975'<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1976to this element, thus computing a value of '<tt>int*</tt>' type.</p>
1977
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1978<p>Note that it is perfectly legal to index partially through a
1979structure, returning a pointer to an inner element. Because of this,
1980the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1981
1982<pre>
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1983 int* %foo(%ST* %s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1984 %t1 = getelementptr %ST* %s, int 1 <i>; yields %ST*:%t1</i>
1985 %t2 = getelementptr %ST* %t1, int 0, uint 2 <i>; yields %RT*:%t2</i>
1986 %t3 = getelementptr %RT* %t2, int 0, uint 1 <i>; yields [10 x [20 x int]]*:%t3</i>
1987 %t4 = getelementptr [10 x [20 x int]]* %t3, int 0, int 5 <i>; yields [20 x int]*:%t4</i>
1988 %t5 = getelementptr [20 x int]* %t4, int 0, int 13 <i>; yields int*:%t5</i>
1989 ret int* %t5
1990 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1991</pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1992<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1993<pre>
1994 <i>; yields [12 x ubyte]*:aptr</i>
1995 %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, uint 1
1996</pre>
1997
1998</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1999<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2000<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2001<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]2002<p>The instructions in this category are the "miscellaneous"
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2003instructions, which defy better classification.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2004</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2005<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2006<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
2007Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2008<div class="doc_text">
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2009<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2010<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]2011<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2012<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
2013the SSA graph representing the function.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2014<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2015<p>The type of the incoming values are specified with the first type
2016field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
2017as arguments, with one pair for each predecessor basic block of the
2018current block. Only values of <a href="#t_firstclass">first class</a>
2019type may be used as the value arguments to the PHI node. Only labels
2020may be used as the label arguments.</p>
2021<p>There must be no non-phi instructions between the start of a basic
2022block and the PHI instructions: i.e. PHI instructions must be first in
2023a basic block.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2024<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2025<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
2026value specified by the parameter, depending on which basic block we
2027came from in the last <a href="#terminators">terminator</a> instruction.</p>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2028<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2029<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]2030</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2031
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2032<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2033<div class="doc_subsubsection">
2034 <a name="i_cast">'<tt>cast .. to</tt>' Instruction</a>
2035</div>
2036
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2037<div class="doc_text">
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2038
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2039<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2040
2041<pre>
2042 &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]2043</pre>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2044
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2045<h5>Overview:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2046
2047<p>
2048The '<tt>cast</tt>' instruction is used as the primitive means to convert
2049integers to floating point, change data type sizes, and break type safety (by
2050casting pointers).
2051</p>
2052
2053
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2054<h5>Arguments:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2055
2056<p>
2057The '<tt>cast</tt>' instruction takes a value to cast, which must be a first
2058class value, and a type to cast it to, which must also be a <a
2059href="#t_firstclass">first class</a> type.
2060</p>
2061
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2062<h5>Semantics:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2063
2064<p>
2065This instruction follows the C rules for explicit casts when determining how the
2066data being cast must change to fit in its new container.
2067</p>
2068
2069<p>
2070When casting to bool, any value that would be considered true in the context of
2071a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' values,
2072all else are '<tt>false</tt>'.
2073</p>
2074
2075<p>
2076When extending an integral value from a type of one signness to another (for
2077example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value is sign-extended if the
2078<b>source</b> value is signed, and zero-extended if the source value is
2079unsigned. <tt>bool</tt> values are always zero extended into either zero or
2080one.
2081</p>
2082
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2083<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2084
2085<pre>
2086 %X = cast int 257 to ubyte <i>; yields ubyte:1</i>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame]2087 %Y = cast int 123 to bool <i>; yields bool:true</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2088</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2089</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2090
2091<!-- _______________________________________________________________________ -->
2092<div class="doc_subsubsection">
2093 <a name="i_select">'<tt>select</tt>' Instruction</a>
2094</div>
2095
2096<div class="doc_text">
2097
2098<h5>Syntax:</h5>
2099
2100<pre>
2101 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
2102</pre>
2103
2104<h5>Overview:</h5>
2105
2106<p>
2107The '<tt>select</tt>' instruction is used to choose one value based on a
2108condition, without branching.
2109</p>
2110
2111
2112<h5>Arguments:</h5>
2113
2114<p>
2115The '<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.
2116</p>
2117
2118<h5>Semantics:</h5>
2119
2120<p>
2121If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2122value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2123</p>
2124
2125<h5>Example:</h5>
2126
2127<pre>
2128 %X = select bool true, ubyte 17, ubyte 42 <i>; yields ubyte:17</i>
2129</pre>
2130</div>
2131
2132
2133
2134
2135
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2136<!-- _______________________________________________________________________ -->
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2137<div class="doc_subsubsection">
2138 <a name="i_call">'<tt>call</tt>' Instruction</a>
2139</div>
2140
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2141<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2142
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2143<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2144<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2145 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] &lt;ty&gt;* &lt;fnptrval&gt;(&lt;param list&gt;)
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2146</pre>
2147
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2148<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2149
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2150<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2151
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2152<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2153
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2154<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2155
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2156<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2157 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2158 <p>The optional "tail" marker indicates whether the callee function accesses
2159 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2160 function call is eligible for tail call optimization. Note that calls may
2161 be marked "tail" even if they do not occur before a <a
2162 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2163 </li>
2164 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2165 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
2166 convention</a> the call should use. If none is specified, the call defaults
2167 to using C calling conventions.
2168 </li>
2169 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2170 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
2171 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2172 signature. This type can be omitted if the function is not varargs and
2173 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2174 </li>
2175 <li>
2176 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
2177 be invoked. In most cases, this is a direct function invocation, but
2178 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2179 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2180 </li>
2181 <li>
2182 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]2183 function signature argument types. All arguments must be of
2184 <a href="#t_firstclass">first class</a> type. If the function signature
2185 indicates the function accepts a variable number of arguments, the extra
2186 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2187 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2188</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2189
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2190<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2191
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2192<p>The '<tt>call</tt>' instruction is used to cause control flow to
2193transfer to a specified function, with its incoming arguments bound to
2194the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
2195instruction in the called function, control flow continues with the
2196instruction after the function call, and the return value of the
2197function is bound to the result argument. This is a simpler case of
2198the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2199
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2200<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2201
2202<pre>
2203 %retval = call int %test(int %argc)
2204 call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42);
2205 %X = tail call int %foo()
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2206 %Y = tail call <a href="#callingconv">fastcc</a> int %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2207</pre>
2208
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2209</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2210
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2211<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2212<div class="doc_subsubsection">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2213 <a name="i_vaarg">'<tt>vaarg</tt>' Instruction</a>
2214</div>
2215
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2216<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2217
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2218<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2219
2220<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2221 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2222</pre>
2223
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2224<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2225
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2226<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2227the "variable argument" area of a function call. It is used to implement the
2228<tt>va_arg</tt> macro in C.</p>
2229
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2230<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2231
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2232<p>This instruction takes a <tt>va_list*</tt> value and the type of
2233the argument. It returns a value of the specified argument type and
2234increments the <tt>va_list</tt> to poin to the next argument. Again, the
2235actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2236
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2237<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2238
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2239<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
2240type from the specified <tt>va_list</tt> and causes the
2241<tt>va_list</tt> to point to the next argument. For more information,
2242see the variable argument handling <a href="#int_varargs">Intrinsic
2243Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2244
2245<p>It is legal for this instruction to be called in a function which does not
2246take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2247function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2248
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2249<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2250href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2251argument.</p>
2252
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2253<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2254
2255<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
2256
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2257</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2258
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2259<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2260<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
2261<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2262
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2263<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2264
2265<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2266well known names and semantics and are required to follow certain
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2267restrictions. Overall, these instructions represent an extension mechanism for
2268the LLVM language that does not require changing all of the transformations in
2269LLVM to add to the language (or the bytecode reader/writer, the parser,
2270etc...).</p>
2271
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2272<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
2273prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2274this. Intrinsic functions must always be external functions: you cannot define
2275the body of intrinsic functions. Intrinsic functions may only be used in call
2276or invoke instructions: it is illegal to take the address of an intrinsic
2277function. Additionally, because intrinsic functions are part of the LLVM
2278language, it is required that they all be documented here if any are added.</p>
2279
2280
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2281<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner590cff32005-05-11 03:35:57 +0000[diff] [blame]2282href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2283</p>
2284
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2285</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2286
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2287<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2288<div class="doc_subsection">
2289 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
2290</div>
2291
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2292<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2293
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2294<p>Variable argument support is defined in LLVM with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2295 href="#i_vanext"><tt>vanext</tt></a> instruction and these three
2296intrinsic functions. These functions are related to the similarly
2297named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2298
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2299<p>All of these functions operate on arguments that use a
2300target-specific value type "<tt>va_list</tt>". The LLVM assembly
2301language reference manual does not define what this type is, so all
2302transformations should be prepared to handle intrinsics with any type
2303used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2304
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2305<p>This example shows how the <a href="#i_vanext"><tt>vanext</tt></a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2306instruction and the variable argument handling intrinsic functions are
2307used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2308
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2309<pre>
2310int %test(int %X, ...) {
2311 ; Initialize variable argument processing
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2312 %ap = alloca sbyte*
2313 call void %<a href="#i_va_start">llvm.va_start</a>(sbyte** %ap)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2314
2315 ; Read a single integer argument
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2316 %tmp = va_arg sbyte** %ap, int
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2317
2318 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2319 %aq = alloca sbyte*
2320 %apv = load sbyte** %ap
2321 call void %<a href="#i_va_copy">llvm.va_copy</a>(sbyte** %aq, sbyte* %apv)
2322 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %aq)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2323
2324 ; Stop processing of arguments.
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2325 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %ap)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2326 ret int %tmp
2327}
2328</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2329</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2330
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2331<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2332<div class="doc_subsubsection">
2333 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
2334</div>
2335
2336
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2337<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2338<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2339<pre> declare void %llvm.va_start(&lt;va_list&gt;* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2340<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2341<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
2342<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
2343href="#i_va_arg">va_arg</a></tt>.</p>
2344
2345<h5>Arguments:</h5>
2346
2347<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
2348
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2349<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2350
2351<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
2352macro available in C. In a target-dependent way, it initializes the
2353<tt>va_list</tt> element the argument points to, so that the next call to
2354<tt>va_arg</tt> will produce the first variable argument passed to the function.
2355Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
2356last argument of the function, the compiler can figure that out.</p>
2357
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2358</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2359
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2360<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2361<div class="doc_subsubsection">
2362 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
2363</div>
2364
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2365<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2366<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2367<pre> declare void %llvm.va_end(&lt;va_list*&gt; &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2368<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2369<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
2370which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
2371or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2372<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2373<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2374<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2375<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]2376macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
2377Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
2378 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
2379with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2380</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2381
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2382<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2383<div class="doc_subsubsection">
2384 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
2385</div>
2386
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2387<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2388
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2389<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2390
2391<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2392 declare void %llvm.va_copy(&lt;va_list&gt;* &lt;destarglist&gt;,
2393 &lt;va_list&gt; &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2394</pre>
2395
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2396<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2397
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2398<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
2399the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2400
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2401<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2402
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2403<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
2404The second argument is a <tt>va_list</tt> element to copy from.</p>
2405
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2406
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2407<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2408
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame^]2409<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
2410available in C. In a target-dependent way, it copies the source
2411<tt>va_list</tt> element into the destination list. This intrinsic is necessary
2412because the <tt><a href="i_va_begin">llvm.va_begin</a></tt> intrinsic may be
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2413arbitrarily complex and require memory allocation, for example.</p>
2414
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2415</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2416
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2417<!-- ======================================================================= -->
2418<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2419 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
2420</div>
2421
2422<div class="doc_text">
2423
2424<p>
2425LLVM support for <a href="GarbageCollection.html">Accurate Garbage
2426Collection</a> requires the implementation and generation of these intrinsics.
2427These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
2428stack</a>, as well as garbage collector implementations that require <a
2429href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
2430Front-ends for type-safe garbage collected languages should generate these
2431intrinsics to make use of the LLVM garbage collectors. For more details, see <a
2432href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
2433</p>
2434</div>
2435
2436<!-- _______________________________________________________________________ -->
2437<div class="doc_subsubsection">
2438 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
2439</div>
2440
2441<div class="doc_text">
2442
2443<h5>Syntax:</h5>
2444
2445<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2446 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2447</pre>
2448
2449<h5>Overview:</h5>
2450
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2451<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2452the code generator, and allows some metadata to be associated with it.</p>
2453
2454<h5>Arguments:</h5>
2455
2456<p>The first argument specifies the address of a stack object that contains the
2457root pointer. The second pointer (which must be either a constant or a global
2458value address) contains the meta-data to be associated with the root.</p>
2459
2460<h5>Semantics:</h5>
2461
2462<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
2463location. At compile-time, the code generator generates information to allow
2464the runtime to find the pointer at GC safe points.
2465</p>
2466
2467</div>
2468
2469
2470<!-- _______________________________________________________________________ -->
2471<div class="doc_subsubsection">
2472 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
2473</div>
2474
2475<div class="doc_text">
2476
2477<h5>Syntax:</h5>
2478
2479<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2480 declare sbyte* %llvm.gcread(sbyte** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2481</pre>
2482
2483<h5>Overview:</h5>
2484
2485<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
2486locations, allowing garbage collector implementations that require read
2487barriers.</p>
2488
2489<h5>Arguments:</h5>
2490
2491<p>The argument is the address to read from, which should be an address
2492allocated from the garbage collector.</p>
2493
2494<h5>Semantics:</h5>
2495
2496<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
2497instruction, but may be replaced with substantially more complex code by the
2498garbage collector runtime, as needed.</p>
2499
2500</div>
2501
2502
2503<!-- _______________________________________________________________________ -->
2504<div class="doc_subsubsection">
2505 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
2506</div>
2507
2508<div class="doc_text">
2509
2510<h5>Syntax:</h5>
2511
2512<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2513 declare void %llvm.gcwrite(sbyte* %P1, sbyte** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2514</pre>
2515
2516<h5>Overview:</h5>
2517
2518<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
2519locations, allowing garbage collector implementations that require write
2520barriers (such as generational or reference counting collectors).</p>
2521
2522<h5>Arguments:</h5>
2523
2524<p>The first argument is the reference to store, and the second is the heap
2525location to store to.</p>
2526
2527<h5>Semantics:</h5>
2528
2529<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
2530instruction, but may be replaced with substantially more complex code by the
2531garbage collector runtime, as needed.</p>
2532
2533</div>
2534
2535
2536
2537<!-- ======================================================================= -->
2538<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2539 <a name="int_codegen">Code Generator Intrinsics</a>
2540</div>
2541
2542<div class="doc_text">
2543<p>
2544These intrinsics are provided by LLVM to expose special features that may only
2545be implemented with code generator support.
2546</p>
2547
2548</div>
2549
2550<!-- _______________________________________________________________________ -->
2551<div class="doc_subsubsection">
2552 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
2553</div>
2554
2555<div class="doc_text">
2556
2557<h5>Syntax:</h5>
2558<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2559 declare void* %llvm.returnaddress(uint &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2560</pre>
2561
2562<h5>Overview:</h5>
2563
2564<p>
2565The '<tt>llvm.returnaddress</tt>' intrinsic returns a target-specific value
2566indicating the return address of the current function or one of its callers.
2567</p>
2568
2569<h5>Arguments:</h5>
2570
2571<p>
2572The argument to this intrinsic indicates which function to return the address
2573for. Zero indicates the calling function, one indicates its caller, etc. The
2574argument is <b>required</b> to be a constant integer value.
2575</p>
2576
2577<h5>Semantics:</h5>
2578
2579<p>
2580The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
2581the return address of the specified call frame, or zero if it cannot be
2582identified. The value returned by this intrinsic is likely to be incorrect or 0
2583for arguments other than zero, so it should only be used for debugging purposes.
2584</p>
2585
2586<p>
2587Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]2588aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2589source-language caller.
2590</p>
2591</div>
2592
2593
2594<!-- _______________________________________________________________________ -->
2595<div class="doc_subsubsection">
2596 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
2597</div>
2598
2599<div class="doc_text">
2600
2601<h5>Syntax:</h5>
2602<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2603 declare void* %llvm.frameaddress(uint &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2604</pre>
2605
2606<h5>Overview:</h5>
2607
2608<p>
2609The '<tt>llvm.frameaddress</tt>' intrinsic returns the target-specific frame
2610pointer value for the specified stack frame.
2611</p>
2612
2613<h5>Arguments:</h5>
2614
2615<p>
2616The argument to this intrinsic indicates which function to return the frame
2617pointer for. Zero indicates the calling function, one indicates its caller,
2618etc. The argument is <b>required</b> to be a constant integer value.
2619</p>
2620
2621<h5>Semantics:</h5>
2622
2623<p>
2624The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
2625the frame address of the specified call frame, or zero if it cannot be
2626identified. The value returned by this intrinsic is likely to be incorrect or 0
2627for arguments other than zero, so it should only be used for debugging purposes.
2628</p>
2629
2630<p>
2631Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]2632aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2633source-language caller.
2634</p>
2635</div>
2636
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]2637<!-- _______________________________________________________________________ -->
2638<div class="doc_subsubsection">
2639 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
2640</div>
2641
2642<div class="doc_text">
2643
2644<h5>Syntax:</h5>
2645<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2646 declare void %llvm.prefetch(sbyte * &lt;address&gt;,
2647 uint &lt;rw&gt;, uint &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]2648</pre>
2649
2650<h5>Overview:</h5>
2651
2652
2653<p>
2654The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2655a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
2656no
2657effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]2658characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]2659</p>
2660
2661<h5>Arguments:</h5>
2662
2663<p>
2664<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
2665determining if the fetch should be for a read (0) or write (1), and
2666<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]2667locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]2668<tt>locality</tt> arguments must be constant integers.
2669</p>
2670
2671<h5>Semantics:</h5>
2672
2673<p>
2674This intrinsic does not modify the behavior of the program. In particular,
2675prefetches cannot trap and do not produce a value. On targets that support this
2676intrinsic, the prefetch can provide hints to the processor cache for better
2677performance.
2678</p>
2679
2680</div>
2681
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]2682<!-- _______________________________________________________________________ -->
2683<div class="doc_subsubsection">
2684 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
2685</div>
2686
2687<div class="doc_text">
2688
2689<h5>Syntax:</h5>
2690<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2691 declare void %llvm.pcmarker( uint &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]2692</pre>
2693
2694<h5>Overview:</h5>
2695
2696
2697<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2698The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
2699(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]2700code to simulators and other tools. The method is target specific, but it is
2701expected that the marker will use exported symbols to transmit the PC of the marker.
2702The marker makes no guaranties that it will remain with any specific instruction
2703after optimizations. It is possible that the presense of a marker will inhibit
2704optimizations. The intended use is to be inserted after optmizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2705correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]2706</p>
2707
2708<h5>Arguments:</h5>
2709
2710<p>
2711<tt>id</tt> is a numerical id identifying the marker.
2712</p>
2713
2714<h5>Semantics:</h5>
2715
2716<p>
2717This intrinsic does not modify the behavior of the program. Backends that do not
2718support this intrinisic may ignore it.
2719</p>
2720
2721</div>
2722
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]2723
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2724<!-- ======================================================================= -->
2725<div class="doc_subsection">
2726 <a name="int_os">Operating System Intrinsics</a>
2727</div>
2728
2729<div class="doc_text">
2730<p>
2731These intrinsics are provided by LLVM to support the implementation of
2732operating system level code.
2733</p>
2734
2735</div>
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2736
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2737<!-- _______________________________________________________________________ -->
2738<div class="doc_subsubsection">
2739 <a name="i_readport">'<tt>llvm.readport</tt>' Intrinsic</a>
2740</div>
2741
2742<div class="doc_text">
2743
2744<h5>Syntax:</h5>
2745<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2746 declare &lt;integer type&gt; %llvm.readport (&lt;integer type&gt; &lt;address&gt;)
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2747</pre>
2748
2749<h5>Overview:</h5>
2750
2751<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2752The '<tt>llvm.readport</tt>' intrinsic reads data from the specified hardware
2753I/O port.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2754</p>
2755
2756<h5>Arguments:</h5>
2757
2758<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2759The argument to this intrinsic indicates the hardware I/O address from which
2760to read the data. The address is in the hardware I/O address namespace (as
2761opposed to being a memory location for memory mapped I/O).
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2762</p>
2763
2764<h5>Semantics:</h5>
2765
2766<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2767The '<tt>llvm.readport</tt>' intrinsic reads data from the hardware I/O port
2768specified by <i>address</i> and returns the value. The address and return
2769value must be integers, but the size is dependent upon the platform upon which
2770the program is code generated. For example, on x86, the address must be an
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]2771unsigned 16-bit value, and the return value must be 8, 16, or 32 bits.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2772</p>
2773
2774</div>
2775
2776<!-- _______________________________________________________________________ -->
2777<div class="doc_subsubsection">
2778 <a name="i_writeport">'<tt>llvm.writeport</tt>' Intrinsic</a>
2779</div>
2780
2781<div class="doc_text">
2782
2783<h5>Syntax:</h5>
2784<pre>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2785 call void (&lt;integer type&gt;, &lt;integer type&gt;)*
2786 %llvm.writeport (&lt;integer type&gt; &lt;value&gt;,
2787 &lt;integer type&gt; &lt;address&gt;)
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2788</pre>
2789
2790<h5>Overview:</h5>
2791
2792<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2793The '<tt>llvm.writeport</tt>' intrinsic writes data to the specified hardware
2794I/O port.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2795</p>
2796
2797<h5>Arguments:</h5>
2798
2799<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2800The first argument is the value to write to the I/O port.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2801</p>
2802
2803<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2804The second argument indicates the hardware I/O address to which data should be
2805written. The address is in the hardware I/O address namespace (as opposed to
2806being a memory location for memory mapped I/O).
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2807</p>
2808
2809<h5>Semantics:</h5>
2810
2811<p>
2812The '<tt>llvm.writeport</tt>' intrinsic writes <i>value</i> to the I/O port
2813specified by <i>address</i>. The address and value must be integers, but the
2814size is dependent upon the platform upon which the program is code generated.
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]2815For example, on x86, the address must be an unsigned 16-bit value, and the
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2816value written must be 8, 16, or 32 bits in length.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2817</p>
2818
2819</div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2820
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2821<!-- _______________________________________________________________________ -->
2822<div class="doc_subsubsection">
2823 <a name="i_readio">'<tt>llvm.readio</tt>' Intrinsic</a>
2824</div>
2825
2826<div class="doc_text">
2827
2828<h5>Syntax:</h5>
2829<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2830 declare &lt;result&gt; %llvm.readio (&lt;ty&gt; * &lt;pointer&gt;)
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2831</pre>
2832
2833<h5>Overview:</h5>
2834
2835<p>
2836The '<tt>llvm.readio</tt>' intrinsic reads data from a memory mapped I/O
2837address.
2838</p>
2839
2840<h5>Arguments:</h5>
2841
2842<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2843The argument to this intrinsic is a pointer indicating the memory address from
2844which to read the data. The data must be a
2845<a href="#t_firstclass">first class</a> type.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2846</p>
2847
2848<h5>Semantics:</h5>
2849
2850<p>
2851The '<tt>llvm.readio</tt>' intrinsic reads data from a memory mapped I/O
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2852location specified by <i>pointer</i> and returns the value. The argument must
2853be a pointer, and the return value must be a
2854<a href="#t_firstclass">first class</a> type. However, certain architectures
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]2855may not support I/O on all first class types. For example, 32-bit processors
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2856may only support I/O on data types that are 32 bits or less.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2857</p>
2858
2859<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2860This intrinsic enforces an in-order memory model for llvm.readio and
2861llvm.writeio calls on machines that use dynamic scheduling. Dynamically
2862scheduled processors may execute loads and stores out of order, re-ordering at
2863run time accesses to memory mapped I/O registers. Using these intrinsics
2864ensures that accesses to memory mapped I/O registers occur in program order.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2865</p>
2866
2867</div>
2868
2869<!-- _______________________________________________________________________ -->
2870<div class="doc_subsubsection">
2871 <a name="i_writeio">'<tt>llvm.writeio</tt>' Intrinsic</a>
2872</div>
2873
2874<div class="doc_text">
2875
2876<h5>Syntax:</h5>
2877<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2878 declare void %llvm.writeio (&lt;ty1&gt; &lt;value&gt;, &lt;ty2&gt; * &lt;pointer&gt;)
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2879</pre>
2880
2881<h5>Overview:</h5>
2882
2883<p>
2884The '<tt>llvm.writeio</tt>' intrinsic writes data to the specified memory
2885mapped I/O address.
2886</p>
2887
2888<h5>Arguments:</h5>
2889
2890<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2891The first argument is the value to write to the memory mapped I/O location.
2892The second argument is a pointer indicating the memory address to which the
2893data should be written.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2894</p>
2895
2896<h5>Semantics:</h5>
2897
2898<p>
2899The '<tt>llvm.writeio</tt>' intrinsic writes <i>value</i> to the memory mapped
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2900I/O address specified by <i>pointer</i>. The value must be a
2901<a href="#t_firstclass">first class</a> type. However, certain architectures
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]2902may not support I/O on all first class types. For example, 32-bit processors
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2903may only support I/O on data types that are 32 bits or less.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2904</p>
2905
2906<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2907This intrinsic enforces an in-order memory model for llvm.readio and
2908llvm.writeio calls on machines that use dynamic scheduling. Dynamically
2909scheduled processors may execute loads and stores out of order, re-ordering at
2910run time accesses to memory mapped I/O registers. Using these intrinsics
2911ensures that accesses to memory mapped I/O registers occur in program order.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2912</p>
2913
2914</div>
2915
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2916<!-- ======================================================================= -->
2917<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2918 <a name="int_libc">Standard C Library Intrinsics</a>
2919</div>
2920
2921<div class="doc_text">
2922<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2923LLVM provides intrinsics for a few important standard C library functions.
2924These intrinsics allow source-language front-ends to pass information about the
2925alignment of the pointer arguments to the code generator, providing opportunity
2926for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2927</p>
2928
2929</div>
2930
2931<!-- _______________________________________________________________________ -->
2932<div class="doc_subsubsection">
2933 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
2934</div>
2935
2936<div class="doc_text">
2937
2938<h5>Syntax:</h5>
2939<pre>
Reid Spencerd4622352005-04-26 20:41:16 +0000[diff] [blame]2940 declare void %llvm.memcpy(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
2941 uint &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2942</pre>
2943
2944<h5>Overview:</h5>
2945
2946<p>
2947The '<tt>llvm.memcpy</tt>' intrinsic copies a block of memory from the source
2948location to the destination location.
2949</p>
2950
2951<p>
2952Note that, unlike the standard libc function, the <tt>llvm.memcpy</tt> intrinsic
2953does not return a value, and takes an extra alignment argument.
2954</p>
2955
2956<h5>Arguments:</h5>
2957
2958<p>
2959The first argument is a pointer to the destination, the second is a pointer to
2960the source. The third argument is an (arbitrarily sized) integer argument
2961specifying the number of bytes to copy, and the fourth argument is the alignment
2962of the source and destination locations.
2963</p>
2964
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]2965<p>
2966If the call to this intrinisic has an alignment value that is not 0 or 1, then
2967the caller guarantees that the size of the copy is a multiple of the alignment
2968and that both the source and destination pointers are aligned to that boundary.
2969</p>
2970
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2971<h5>Semantics:</h5>
2972
2973<p>
2974The '<tt>llvm.memcpy</tt>' intrinsic copies a block of memory from the source
2975location to the destination location, which are not allowed to overlap. It
2976copies "len" bytes of memory over. If the argument is known to be aligned to
2977some boundary, this can be specified as the fourth argument, otherwise it should
2978be set to 0 or 1.
2979</p>
2980</div>
2981
2982
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]2983<!-- _______________________________________________________________________ -->
2984<div class="doc_subsubsection">
2985 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
2986</div>
2987
2988<div class="doc_text">
2989
2990<h5>Syntax:</h5>
2991<pre>
Reid Spencerd4622352005-04-26 20:41:16 +0000[diff] [blame]2992 declare void %llvm.memmove(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
2993 uint &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]2994</pre>
2995
2996<h5>Overview:</h5>
2997
2998<p>
2999The '<tt>llvm.memmove</tt>' intrinsic moves a block of memory from the source
3000location to the destination location. It is similar to the '<tt>llvm.memcpy</tt>'
3001intrinsic but allows the two memory locations to overlap.
3002</p>
3003
3004<p>
3005Note that, unlike the standard libc function, the <tt>llvm.memmove</tt> intrinsic
3006does not return a value, and takes an extra alignment argument.
3007</p>
3008
3009<h5>Arguments:</h5>
3010
3011<p>
3012The first argument is a pointer to the destination, the second is a pointer to
3013the source. The third argument is an (arbitrarily sized) integer argument
3014specifying the number of bytes to copy, and the fourth argument is the alignment
3015of the source and destination locations.
3016</p>
3017
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3018<p>
3019If the call to this intrinisic has an alignment value that is not 0 or 1, then
3020the caller guarantees that the size of the copy is a multiple of the alignment
3021and that both the source and destination pointers are aligned to that boundary.
3022</p>
3023
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3024<h5>Semantics:</h5>
3025
3026<p>
3027The '<tt>llvm.memmove</tt>' intrinsic copies a block of memory from the source
3028location to the destination location, which may overlap. It
3029copies "len" bytes of memory over. If the argument is known to be aligned to
3030some boundary, this can be specified as the fourth argument, otherwise it should
3031be set to 0 or 1.
3032</p>
3033</div>
3034
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3035
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3036<!-- _______________________________________________________________________ -->
3037<div class="doc_subsubsection">
3038 <a name="i_memset">'<tt>llvm.memset</tt>' Intrinsic</a>
3039</div>
3040
3041<div class="doc_text">
3042
3043<h5>Syntax:</h5>
3044<pre>
Reid Spencerd4622352005-04-26 20:41:16 +0000[diff] [blame]3045 declare void %llvm.memset(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
3046 uint &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3047</pre>
3048
3049<h5>Overview:</h5>
3050
3051<p>
3052The '<tt>llvm.memset</tt>' intrinsic fills a block of memory with a particular
3053byte value.
3054</p>
3055
3056<p>
3057Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
3058does not return a value, and takes an extra alignment argument.
3059</p>
3060
3061<h5>Arguments:</h5>
3062
3063<p>
3064The first argument is a pointer to the destination to fill, the second is the
3065byte value to fill it with, the third argument is an (arbitrarily sized) integer
3066argument specifying the number of bytes to fill, and the fourth argument is the
3067known alignment of destination location.
3068</p>
3069
3070<p>
3071If the call to this intrinisic has an alignment value that is not 0 or 1, then
3072the caller guarantees that the size of the copy is a multiple of the alignment
3073and that the destination pointer is aligned to that boundary.
3074</p>
3075
3076<h5>Semantics:</h5>
3077
3078<p>
3079The '<tt>llvm.memset</tt>' intrinsic fills "len" bytes of memory starting at the
3080destination location. If the argument is known to be aligned to some boundary,
3081this can be specified as the fourth argument, otherwise it should be set to 0 or
30821.
3083</p>
3084</div>
3085
3086
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]3087<!-- _______________________________________________________________________ -->
3088<div class="doc_subsubsection">
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]3089 <a name="i_isunordered">'<tt>llvm.isunordered</tt>' Intrinsic</a>
3090</div>
3091
3092<div class="doc_text">
3093
3094<h5>Syntax:</h5>
3095<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3096 declare bool %llvm.isunordered(&lt;float or double&gt; Val1, &lt;float or double&gt; Val2)
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]3097</pre>
3098
3099<h5>Overview:</h5>
3100
3101<p>
3102The '<tt>llvm.isunordered</tt>' intrinsic returns true if either or both of the
3103specified floating point values is a NAN.
3104</p>
3105
3106<h5>Arguments:</h5>
3107
3108<p>
3109The arguments are floating point numbers of the same type.
3110</p>
3111
3112<h5>Semantics:</h5>
3113
3114<p>
3115If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
3116false.
3117</p>
3118</div>
3119
3120
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3121<!-- ======================================================================= -->
3122<div class="doc_subsection">
3123 <a name="int_count">Bit Counting Intrinsics</a>
3124</div>
3125
3126<div class="doc_text">
3127<p>
3128LLVM provides intrinsics for a few important bit counting operations.
3129These allow efficient code generation for some algorithms.
3130</p>
3131
3132</div>
3133
3134<!-- _______________________________________________________________________ -->
3135<div class="doc_subsubsection">
3136 <a name="int_ctpop">'<tt>llvm.ctpop</tt>' Intrinsic</a>
3137</div>
3138
3139<div class="doc_text">
3140
3141<h5>Syntax:</h5>
3142<pre>
3143 declare int %llvm.ctpop(int &lt;src&gt;)
3144
3145</pre>
3146
3147<h5>Overview:</h5>
3148
3149<p>
3150The '<tt>llvm.ctpop</tt>' intrinsic counts the number of ones in a variable.
3151</p>
3152
3153<h5>Arguments:</h5>
3154
3155<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]3156The only argument is the value to be counted. The argument may be of any
3157integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3158</p>
3159
3160<h5>Semantics:</h5>
3161
3162<p>
3163The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
3164</p>
3165</div>
3166
3167<!-- _______________________________________________________________________ -->
3168<div class="doc_subsubsection">
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3169 <a name="int_ctlz">'<tt>llvm.ctlz</tt>' Intrinsic</a>
3170</div>
3171
3172<div class="doc_text">
3173
3174<h5>Syntax:</h5>
3175<pre>
3176 declare int %llvm.ctlz(int &lt;src&gt;)
3177
3178</pre>
3179
3180<h5>Overview:</h5>
3181
3182<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]3183The '<tt>llvm.ctlz</tt>' intrinsic counts the number of leading zeros in a
3184variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3185</p>
3186
3187<h5>Arguments:</h5>
3188
3189<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]3190The only argument is the value to be counted. The argument may be of any
3191integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3192</p>
3193
3194<h5>Semantics:</h5>
3195
3196<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3197The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
3198in a variable. If the src == 0 then the result is the size in bits of the type
3199of src. For example, <tt>llvm.cttz(int 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3200</p>
3201</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]3202
3203
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3204
3205<!-- _______________________________________________________________________ -->
3206<div class="doc_subsubsection">
3207 <a name="int_cttz">'<tt>llvm.cttz</tt>' Intrinsic</a>
3208</div>
3209
3210<div class="doc_text">
3211
3212<h5>Syntax:</h5>
3213<pre>
3214 declare int %llvm.cttz(int &lt;src&gt;)
3215
3216</pre>
3217
3218<h5>Overview:</h5>
3219
3220<p>
3221The '<tt>llvm.cttz</tt>' intrinsic counts the number of trailing zeros.
3222</p>
3223
3224<h5>Arguments:</h5>
3225
3226<p>
3227The only argument is the value to be counted. The argument may be of any
3228integer type. The return type must match the argument type.
3229</p>
3230
3231<h5>Semantics:</h5>
3232
3233<p>
3234The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
3235in a variable. If the src == 0 then the result is the size in bits of the type
3236of src. For example, <tt>llvm.cttz(2) = 1</tt>.
3237</p>
3238</div>
3239
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3240<!-- ======================================================================= -->
3241<div class="doc_subsection">
3242 <a name="int_debugger">Debugger Intrinsics</a>
3243</div>
3244
3245<div class="doc_text">
3246<p>
3247The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
3248are described in the <a
3249href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
3250Debugging</a> document.
3251</p>
3252</div>
3253
3254
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3255<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3256<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]3257<address>
3258 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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3262
3263 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
3264 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
3265 Last modified: $Date$
3266</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3267</body>
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