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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>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
27 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]28 </ol>
29 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]30 <li><a href="#typesystem">Type System</a>
31 <ol>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]32 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]33 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]34 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]35 </ol>
36 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]37 <li><a href="#t_derived">Derived Types</a>
38 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]39 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]40 <li><a href="#t_function">Function Type</a></li>
41 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]42 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]43 <li><a href="#t_packed">Packed Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]44 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]45 </ol>
46 </li>
47 </ol>
48 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]49 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]50 <ol>
51 <li><a href="#simpleconstants">Simple Constants</a>
52 <li><a href="#aggregateconstants">Aggregate Constants</a>
53 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
54 <li><a href="#undefvalues">Undefined Values</a>
55 <li><a href="#constantexprs">Constant Expressions</a>
56 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]57 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]58 <li><a href="#othervalues">Other Values</a>
59 <ol>
60 <li><a href="#inlineasm">Inline Assembler Expressions</a>
61 </ol>
62 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]63 <li><a href="#instref">Instruction Reference</a>
64 <ol>
65 <li><a href="#terminators">Terminator Instructions</a>
66 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]67 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
68 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]69 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
70 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]72 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]73 </ol>
74 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]75 <li><a href="#binaryops">Binary Operations</a>
76 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]77 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
78 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
79 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
80 <li><a href="#i_div">'<tt>div</tt>' Instruction</a></li>
81 <li><a href="#i_rem">'<tt>rem</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]82 <li><a href="#i_setcc">'<tt>set<i>cc</i></tt>' Instructions</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]83 </ol>
84 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]85 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
86 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]87 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]88 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]89 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
90 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
91 <li><a href="#i_shr">'<tt>shr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]92 </ol>
93 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]94 <li><a href="#memoryops">Memory Access Operations</a>
95 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]96 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
97 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
98 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]99 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
100 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
101 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]102 </ol>
103 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]104 <li><a href="#otherops">Other Operations</a>
105 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]106 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]107 <li><a href="#i_cast">'<tt>cast .. to</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]108 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]109 <li><a href="#i_vset">'<tt>vset</tt>' Instruction</a></li>
110 <li><a href="#i_vselect">'<tt>vselect</tt>' Instruction</a></li>
Robert Bocchino3a558662006-01-05 17:37:02 +0000[diff] [blame]111 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]112 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]113 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]114 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]115 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]116 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]117 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]118 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]119 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]120 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]121 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
122 <ol>
123 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
124 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
125 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
126 </ol>
127 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]128 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
129 <ol>
130 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
131 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
132 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
133 </ol>
134 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]135 <li><a href="#int_codegen">Code Generator Intrinsics</a>
136 <ol>
137 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
138 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]139 <li><a href="#i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
140 <li><a href="#i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]141 <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]142 <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]143 <li><a href="#i_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]144 </ol>
145 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]146 <li><a href="#int_libc">Standard C Library Intrinsics</a>
147 <ol>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]148 <li><a href="#i_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
149 <li><a href="#i_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
150 <li><a href="#i_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]151 <li><a href="#i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a></li>
152 <li><a href="#i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]153
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]154 </ol>
155 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]156 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]157 <ol>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]158 <li><a href="#i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]159 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
160 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
161 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]162 </ol>
163 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]164 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]165 </ol>
166 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]167</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]168
169<div class="doc_author">
170 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
171 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]172</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]173
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]174<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]175<div class="doc_section"> <a name="abstract">Abstract </a></div>
176<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]177
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]178<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]179<p>This document is a reference manual for the LLVM assembly language.
180LLVM is an SSA based representation that provides type safety,
181low-level operations, flexibility, and the capability of representing
182'all' high-level languages cleanly. It is the common code
183representation used throughout all phases of the LLVM compilation
184strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]185</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]186
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]187<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]188<div class="doc_section"> <a name="introduction">Introduction</a> </div>
189<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]190
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]191<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]192
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]193<p>The LLVM code representation is designed to be used in three
194different forms: as an in-memory compiler IR, as an on-disk bytecode
195representation (suitable for fast loading by a Just-In-Time compiler),
196and as a human readable assembly language representation. This allows
197LLVM to provide a powerful intermediate representation for efficient
198compiler transformations and analysis, while providing a natural means
199to debug and visualize the transformations. The three different forms
200of LLVM are all equivalent. This document describes the human readable
201representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]202
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]203<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]204while being expressive, typed, and extensible at the same time. It
205aims to be a "universal IR" of sorts, by being at a low enough level
206that high-level ideas may be cleanly mapped to it (similar to how
207microprocessors are "universal IR's", allowing many source languages to
208be mapped to them). By providing type information, LLVM can be used as
209the target of optimizations: for example, through pointer analysis, it
210can be proven that a C automatic variable is never accessed outside of
211the current function... allowing it to be promoted to a simple SSA
212value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]213
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]214</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]215
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]216<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]218
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]219<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]220
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]221<p>It is important to note that this document describes 'well formed'
222LLVM assembly language. There is a difference between what the parser
223accepts and what is considered 'well formed'. For example, the
224following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]225
226<pre>
227 %x = <a href="#i_add">add</a> int 1, %x
228</pre>
229
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]230<p>...because the definition of <tt>%x</tt> does not dominate all of
231its uses. The LLVM infrastructure provides a verification pass that may
232be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]233automatically run by the parser after parsing input assembly and by
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]234the optimizer before it outputs bytecode. The violations pointed out
235by the verifier pass indicate bugs in transformation passes or input to
236the parser.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]237
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]238<!-- Describe the typesetting conventions here. --> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]239
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]240<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]241<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]242<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]243
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]244<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]245
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]246<p>LLVM uses three different forms of identifiers, for different
247purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]248
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]249<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]250 <li>Named values are represented as a string of characters with a '%' prefix.
251 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
252 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
253 Identifiers which require other characters in their names can be surrounded
254 with quotes. In this way, anything except a <tt>"</tt> character can be used
255 in a name.</li>
256
257 <li>Unnamed values are represented as an unsigned numeric value with a '%'
258 prefix. For example, %12, %2, %44.</li>
259
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]260 <li>Constants, which are described in a <a href="#constants">section about
261 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]262</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]263
264<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
265don't need to worry about name clashes with reserved words, and the set of
266reserved words may be expanded in the future without penalty. Additionally,
267unnamed identifiers allow a compiler to quickly come up with a temporary
268variable without having to avoid symbol table conflicts.</p>
269
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]270<p>Reserved words in LLVM are very similar to reserved words in other
271languages. There are keywords for different opcodes ('<tt><a
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]272href="#i_add">add</a></tt>', '<tt><a href="#i_cast">cast</a></tt>', '<tt><a
273href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
274href="#t_void">void</a></tt>', '<tt><a href="#t_uint">uint</a></tt>', etc...),
275and others. These reserved words cannot conflict with variable names, because
276none of them start with a '%' character.</p>
277
278<p>Here is an example of LLVM code to multiply the integer variable
279'<tt>%X</tt>' by 8:</p>
280
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]281<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]282
283<pre>
284 %result = <a href="#i_mul">mul</a> uint %X, 8
285</pre>
286
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]287<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]288
289<pre>
290 %result = <a href="#i_shl">shl</a> uint %X, ubyte 3
291</pre>
292
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]293<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]294
295<pre>
296 <a href="#i_add">add</a> uint %X, %X <i>; yields {uint}:%0</i>
297 <a href="#i_add">add</a> uint %0, %0 <i>; yields {uint}:%1</i>
298 %result = <a href="#i_add">add</a> uint %1, %1
299</pre>
300
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]301<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
302important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]303
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]304<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]305
306 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
307 line.</li>
308
309 <li>Unnamed temporaries are created when the result of a computation is not
310 assigned to a named value.</li>
311
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]312 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]313
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]314</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]315
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]316<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]317demonstrating instructions, we will follow an instruction with a comment that
318defines the type and name of value produced. Comments are shown in italic
319text.</p>
320
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]321</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]322
323<!-- *********************************************************************** -->
324<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
325<!-- *********************************************************************** -->
326
327<!-- ======================================================================= -->
328<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
329</div>
330
331<div class="doc_text">
332
333<p>LLVM programs are composed of "Module"s, each of which is a
334translation unit of the input programs. Each module consists of
335functions, global variables, and symbol table entries. Modules may be
336combined together with the LLVM linker, which merges function (and
337global variable) definitions, resolves forward declarations, and merges
338symbol table entries. Here is an example of the "hello world" module:</p>
339
340<pre><i>; Declare the string constant as a global constant...</i>
341<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
342 href="#globalvars">constant</a> <a href="#t_array">[13 x sbyte]</a> c"hello world\0A\00" <i>; [13 x sbyte]*</i>
343
344<i>; External declaration of the puts function</i>
345<a href="#functionstructure">declare</a> int %puts(sbyte*) <i>; int(sbyte*)* </i>
346
347<i>; Definition of main function</i>
348int %main() { <i>; int()* </i>
349 <i>; Convert [13x sbyte]* to sbyte *...</i>
350 %cast210 = <a
351 href="#i_getelementptr">getelementptr</a> [13 x sbyte]* %.LC0, long 0, long 0 <i>; sbyte*</i>
352
353 <i>; Call puts function to write out the string to stdout...</i>
354 <a
355 href="#i_call">call</a> int %puts(sbyte* %cast210) <i>; int</i>
356 <a
357 href="#i_ret">ret</a> int 0<br>}<br></pre>
358
359<p>This example is made up of a <a href="#globalvars">global variable</a>
360named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
361function, and a <a href="#functionstructure">function definition</a>
362for "<tt>main</tt>".</p>
363
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]364<p>In general, a module is made up of a list of global values,
365where both functions and global variables are global values. Global values are
366represented by a pointer to a memory location (in this case, a pointer to an
367array of char, and a pointer to a function), and have one of the following <a
368href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]369
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]370</div>
371
372<!-- ======================================================================= -->
373<div class="doc_subsection">
374 <a name="linkage">Linkage Types</a>
375</div>
376
377<div class="doc_text">
378
379<p>
380All Global Variables and Functions have one of the following types of linkage:
381</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]382
383<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]384
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]385 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]386
387 <dd>Global values with internal linkage are only directly accessible by
388 objects in the current module. In particular, linking code into a module with
389 an internal global value may cause the internal to be renamed as necessary to
390 avoid collisions. Because the symbol is internal to the module, all
391 references can be updated. This corresponds to the notion of the
392 '<tt>static</tt>' keyword in C, or the idea of "anonymous namespaces" in C++.
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_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]396
397 <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with
398 the twist that linking together two modules defining the same
399 <tt>linkonce</tt> globals will cause one of the globals to be discarded. This
400 is typically used to implement inline functions. Unreferenced
401 <tt>linkonce</tt> globals are allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]402 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]403
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]404 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]405
406 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
407 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
408 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]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_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]412
413 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
414 pointer to array type. When two global variables with appending linkage are
415 linked together, the two global arrays are appended together. This is the
416 LLVM, typesafe, equivalent of having the system linker append together
417 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]418 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]419
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]420 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]421
422 <dd>If none of the above identifiers are used, the global is externally
423 visible, meaning that it participates in linkage and can be used to resolve
424 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]425 </dd>
426</dl>
427
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]428<p><a name="linkage_external">For example, since the "<tt>.LC0</tt>"
429variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
430variable and was linked with this one, one of the two would be renamed,
431preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
432external (i.e., lacking any linkage declarations), they are accessible
433outside of the current module. It is illegal for a function <i>declaration</i>
434to have any linkage type other than "externally visible".</a></p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]435
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]436</div>
437
438<!-- ======================================================================= -->
439<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]440 <a name="callingconv">Calling Conventions</a>
441</div>
442
443<div class="doc_text">
444
445<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
446and <a href="#i_invoke">invokes</a> can all have an optional calling convention
447specified for the call. The calling convention of any pair of dynamic
448caller/callee must match, or the behavior of the program is undefined. The
449following calling conventions are supported by LLVM, and more may be added in
450the future:</p>
451
452<dl>
453 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
454
455 <dd>This calling convention (the default if no other calling convention is
456 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]457 supports varargs function calls and tolerates some mismatch in the declared
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]458 prototype and implemented declaration of the function (as does normal C).
459 </dd>
460
461 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
462
463 <dd>This calling convention attempts to make calls as fast as possible
464 (e.g. by passing things in registers). This calling convention allows the
465 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]466 without having to conform to an externally specified ABI. Implementations of
467 this convention should allow arbitrary tail call optimization to be supported.
468 This calling convention does not support varargs and requires the prototype of
469 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]470 </dd>
471
472 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
473
474 <dd>This calling convention attempts to make code in the caller as efficient
475 as possible under the assumption that the call is not commonly executed. As
476 such, these calls often preserve all registers so that the call does not break
477 any live ranges in the caller side. This calling convention does not support
478 varargs and requires the prototype of all callees to exactly match the
479 prototype of the function definition.
480 </dd>
481
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]482 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]483
484 <dd>Any calling convention may be specified by number, allowing
485 target-specific calling conventions to be used. Target specific calling
486 conventions start at 64.
487 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]488</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]489
490<p>More calling conventions can be added/defined on an as-needed basis, to
491support pascal conventions or any other well-known target-independent
492convention.</p>
493
494</div>
495
496<!-- ======================================================================= -->
497<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]498 <a name="globalvars">Global Variables</a>
499</div>
500
501<div class="doc_text">
502
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]503<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]504instead of run-time. Global variables may optionally be initialized, may have
505an explicit section to be placed in, and may
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]506have an optional explicit alignment specified. A
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]507variable may be defined as a global "constant," which indicates that the
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]508contents of the variable will <b>never</b> be modified (enabling better
509optimization, allowing the global data to be placed in the read-only section of
510an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]511cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]512
513<p>
514LLVM explicitly allows <em>declarations</em> of global variables to be marked
515constant, even if the final definition of the global is not. This capability
516can be used to enable slightly better optimization of the program, but requires
517the language definition to guarantee that optimizations based on the
518'constantness' are valid for the translation units that do not include the
519definition.
520</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]521
522<p>As SSA values, global variables define pointer values that are in
523scope (i.e. they dominate) all basic blocks in the program. Global
524variables always define a pointer to their "content" type because they
525describe a region of memory, and all memory objects in LLVM are
526accessed through pointers.</p>
527
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]528<p>LLVM allows an explicit section to be specified for globals. If the target
529supports it, it will emit globals to the section specified.</p>
530
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]531<p>An explicit alignment may be specified for a global. If not present, or if
532the alignment is set to zero, the alignment of the global is set by the target
533to whatever it feels convenient. If an explicit alignment is specified, the
534global is forced to have at least that much alignment. All alignments must be
535a power of 2.</p>
536
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]537</div>
538
539
540<!-- ======================================================================= -->
541<div class="doc_subsection">
542 <a name="functionstructure">Functions</a>
543</div>
544
545<div class="doc_text">
546
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]547<p>LLVM function definitions consist of an optional <a href="#linkage">linkage
548type</a>, an optional <a href="#callingconv">calling convention</a>, a return
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]549type, a function name, a (possibly empty) argument list, an optional section,
550an optional alignment, an opening curly brace,
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]551a list of basic blocks, and a closing curly brace. LLVM function declarations
552are defined with the "<tt>declare</tt>" keyword, an optional <a
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]553href="#callingconv">calling convention</a>, a return type, a function name,
554a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]555
556<p>A function definition contains a list of basic blocks, forming the CFG for
557the function. Each basic block may optionally start with a label (giving the
558basic block a symbol table entry), contains a list of instructions, and ends
559with a <a href="#terminators">terminator</a> instruction (such as a branch or
560function return).</p>
561
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]562<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]563executed on entrance to the function, and it is not allowed to have predecessor
564basic blocks (i.e. there can not be any branches to the entry block of a
565function). Because the block can have no predecessors, it also cannot have any
566<a href="#i_phi">PHI nodes</a>.</p>
567
568<p>LLVM functions are identified by their name and type signature. Hence, two
569functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]570considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]571appropriately.</p>
572
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]573<p>LLVM allows an explicit section to be specified for functions. If the target
574supports it, it will emit functions to the section specified.</p>
575
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]576<p>An explicit alignment may be specified for a function. If not present, or if
577the alignment is set to zero, the alignment of the function is set by the target
578to whatever it feels convenient. If an explicit alignment is specified, the
579function is forced to have at least that much alignment. All alignments must be
580a power of 2.</p>
581
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]582</div>
583
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]584<!-- ======================================================================= -->
585<div class="doc_subsection">
586 <a name="moduleasm">Module-Level Inline Assembly</a></li>
587</div>
588
589<div class="doc_text">
590<p>
591Modules may contain "module-level inline asm" blocks, which corresponds to the
592GCC "file scope inline asm" blocks. These blocks are internally concatenated by
593LLVM and treated as a single unit, but may be separated in the .ll file if
594desired. The syntax is very simple:
595</p>
596
597<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]598 module asm "inline asm code goes here"
599 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]600</pre></div>
601
602<p>The strings can contain any character by escaping non-printable characters.
603 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
604 for the number.
605</p>
606
607<p>
608 The inline asm code is simply printed to the machine code .s file when
609 assembly code is generated.
610</p>
611</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]612
613
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]614<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]615<div class="doc_section"> <a name="typesystem">Type System</a> </div>
616<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]617
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]618<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]619
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]620<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]621intermediate representation. Being typed enables a number of
622optimizations to be performed on the IR directly, without having to do
623extra analyses on the side before the transformation. A strong type
624system makes it easier to read the generated code and enables novel
625analyses and transformations that are not feasible to perform on normal
626three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]627
628</div>
629
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]630<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]631<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]632<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]633<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]634system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]635
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]636<table class="layout">
637 <tr class="layout">
638 <td class="left">
639 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]640 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]641 <tr><th>Type</th><th>Description</th></tr>
642 <tr><td><tt>void</tt></td><td>No value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]643 <tr><td><tt>ubyte</tt></td><td>Unsigned 8-bit value</td></tr>
644 <tr><td><tt>ushort</tt></td><td>Unsigned 16-bit value</td></tr>
645 <tr><td><tt>uint</tt></td><td>Unsigned 32-bit value</td></tr>
646 <tr><td><tt>ulong</tt></td><td>Unsigned 64-bit value</td></tr>
647 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]648 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]649 </tbody>
650 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]651 </td>
652 <td class="right">
653 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]654 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]655 <tr><th>Type</th><th>Description</th></tr>
656 <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]657 <tr><td><tt>sbyte</tt></td><td>Signed 8-bit value</td></tr>
658 <tr><td><tt>short</tt></td><td>Signed 16-bit value</td></tr>
659 <tr><td><tt>int</tt></td><td>Signed 32-bit value</td></tr>
660 <tr><td><tt>long</tt></td><td>Signed 64-bit value</td></tr>
661 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]662 </tbody>
663 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]664 </td>
665 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]666</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]667</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]668
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]669<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]670<div class="doc_subsubsection"> <a name="t_classifications">Type
671Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]672<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]673<p>These different primitive types fall into a few useful
674classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]675
676<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]677 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]678 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]679 <tr>
680 <td><a name="t_signed">signed</a></td>
681 <td><tt>sbyte, short, int, long, float, double</tt></td>
682 </tr>
683 <tr>
684 <td><a name="t_unsigned">unsigned</a></td>
685 <td><tt>ubyte, ushort, uint, ulong</tt></td>
686 </tr>
687 <tr>
688 <td><a name="t_integer">integer</a></td>
689 <td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td>
690 </tr>
691 <tr>
692 <td><a name="t_integral">integral</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]693 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long</tt>
694 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]695 </tr>
696 <tr>
697 <td><a name="t_floating">floating point</a></td>
698 <td><tt>float, double</tt></td>
699 </tr>
700 <tr>
701 <td><a name="t_firstclass">first class</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]702 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long,<br>
703 float, double, <a href="#t_pointer">pointer</a>,
704 <a href="#t_packed">packed</a></tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]705 </tr>
706 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]707</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]708
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]709<p>The <a href="#t_firstclass">first class</a> types are perhaps the
710most important. Values of these types are the only ones which can be
711produced by instructions, passed as arguments, or used as operands to
712instructions. This means that all structures and arrays must be
713manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]714</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]715
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]716<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]717<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]718
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]719<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]720
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]721<p>The real power in LLVM comes from the derived types in the system.
722This is what allows a programmer to represent arrays, functions,
723pointers, and other useful types. Note that these derived types may be
724recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]725
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]726</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]727
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]728<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]729<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]730
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]731<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]732
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]733<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]734
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]735<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]736sequentially in memory. The array type requires a size (number of
737elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]738
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]739<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]740
741<pre>
742 [&lt;# elements&gt; x &lt;elementtype&gt;]
743</pre>
744
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]745<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]746be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]747
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]748<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]749<table class="layout">
750 <tr class="layout">
751 <td class="left">
752 <tt>[40 x int ]</tt><br/>
753 <tt>[41 x int ]</tt><br/>
754 <tt>[40 x uint]</tt><br/>
755 </td>
756 <td class="left">
757 Array of 40 integer values.<br/>
758 Array of 41 integer values.<br/>
759 Array of 40 unsigned integer values.<br/>
760 </td>
761 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]762</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]763<p>Here are some examples of multidimensional arrays:</p>
764<table class="layout">
765 <tr class="layout">
766 <td class="left">
767 <tt>[3 x [4 x int]]</tt><br/>
768 <tt>[12 x [10 x float]]</tt><br/>
769 <tt>[2 x [3 x [4 x uint]]]</tt><br/>
770 </td>
771 <td class="left">
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]772 3x4 array of integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]773 12x10 array of single precision floating point values.<br/>
774 2x3x4 array of unsigned integer values.<br/>
775 </td>
776 </tr>
777</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]778
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]779<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
780length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]781LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
782As a special case, however, zero length arrays are recognized to be variable
783length. This allows implementation of 'pascal style arrays' with the LLVM
784type "{ int, [0 x float]}", for example.</p>
785
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]786</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]787
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]788<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]789<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]790<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]791<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]792<p>The function type can be thought of as a function signature. It
793consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]794Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]795(which are structures of pointers to functions), for indirect function
796calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]797<p>
798The return type of a function type cannot be an aggregate type.
799</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]800<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]801<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]802<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]803specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]804which indicates that the function takes a variable number of arguments.
805Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]806 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]807<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]808<table class="layout">
809 <tr class="layout">
810 <td class="left">
811 <tt>int (int)</tt> <br/>
812 <tt>float (int, int *) *</tt><br/>
813 <tt>int (sbyte *, ...)</tt><br/>
814 </td>
815 <td class="left">
816 function taking an <tt>int</tt>, returning an <tt>int</tt><br/>
817 <a href="#t_pointer">Pointer</a> to a function that takes an
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]818 <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]819 returning <tt>float</tt>.<br/>
820 A vararg function that takes at least one <a href="#t_pointer">pointer</a>
821 to <tt>sbyte</tt> (signed char in C), which returns an integer. This is
822 the signature for <tt>printf</tt> in LLVM.<br/>
823 </td>
824 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]825</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]826
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]827</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]828<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]829<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]830<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]831<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]832<p>The structure type is used to represent a collection of data members
833together in memory. The packing of the field types is defined to match
834the ABI of the underlying processor. The elements of a structure may
835be any type that has a size.</p>
836<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
837and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
838field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
839instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]840<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]841<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]842<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]843<table class="layout">
844 <tr class="layout">
845 <td class="left">
846 <tt>{ int, int, int }</tt><br/>
847 <tt>{ float, int (int) * }</tt><br/>
848 </td>
849 <td class="left">
850 a triple of three <tt>int</tt> values<br/>
851 A pair, where the first element is a <tt>float</tt> and the second element
852 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
853 that takes an <tt>int</tt>, returning an <tt>int</tt>.<br/>
854 </td>
855 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]856</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]857</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]858
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]859<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]860<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]861<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]862<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]863<p>As in many languages, the pointer type represents a pointer or
864reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]865<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]866<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]867<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]868<table class="layout">
869 <tr class="layout">
870 <td class="left">
871 <tt>[4x int]*</tt><br/>
872 <tt>int (int *) *</tt><br/>
873 </td>
874 <td class="left">
875 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
876 four <tt>int</tt> values<br/>
877 A <a href="#t_pointer">pointer</a> to a <a
Chris Lattnera977c482005-02-19 02:22:14 +0000[diff] [blame]878 href="#t_function">function</a> that takes an <tt>int*</tt>, returning an
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]879 <tt>int</tt>.<br/>
880 </td>
881 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]882</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]883</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]884
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]885<!-- _______________________________________________________________________ -->
886<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]887<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]888
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]889<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]890
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]891<p>A packed type is a simple derived type that represents a vector
892of elements. Packed types are used when multiple primitive data
893are operated in parallel using a single instruction (SIMD).
894A packed type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]895elements) and an underlying primitive data type. Vectors must have a power
896of two length (1, 2, 4, 8, 16 ...). Packed types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]897considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]898
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]899<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]900
901<pre>
902 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
903</pre>
904
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]905<p>The number of elements is a constant integer value; elementtype may
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]906be any integral or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]907
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]908<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]909
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]910<table class="layout">
911 <tr class="layout">
912 <td class="left">
913 <tt>&lt;4 x int&gt;</tt><br/>
914 <tt>&lt;8 x float&gt;</tt><br/>
915 <tt>&lt;2 x uint&gt;</tt><br/>
916 </td>
917 <td class="left">
918 Packed vector of 4 integer values.<br/>
919 Packed vector of 8 floating-point values.<br/>
920 Packed vector of 2 unsigned integer values.<br/>
921 </td>
922 </tr>
923</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]924</div>
925
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]926<!-- _______________________________________________________________________ -->
927<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
928<div class="doc_text">
929
930<h5>Overview:</h5>
931
932<p>Opaque types are used to represent unknown types in the system. This
933corresponds (for example) to the C notion of a foward declared structure type.
934In LLVM, opaque types can eventually be resolved to any type (not just a
935structure type).</p>
936
937<h5>Syntax:</h5>
938
939<pre>
940 opaque
941</pre>
942
943<h5>Examples:</h5>
944
945<table class="layout">
946 <tr class="layout">
947 <td class="left">
948 <tt>opaque</tt>
949 </td>
950 <td class="left">
951 An opaque type.<br/>
952 </td>
953 </tr>
954</table>
955</div>
956
957
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]958<!-- *********************************************************************** -->
959<div class="doc_section"> <a name="constants">Constants</a> </div>
960<!-- *********************************************************************** -->
961
962<div class="doc_text">
963
964<p>LLVM has several different basic types of constants. This section describes
965them all and their syntax.</p>
966
967</div>
968
969<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]970<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]971
972<div class="doc_text">
973
974<dl>
975 <dt><b>Boolean constants</b></dt>
976
977 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
978 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
979 </dd>
980
981 <dt><b>Integer constants</b></dt>
982
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]983 <dd>Standard integers (such as '4') are constants of the <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]984 href="#t_integer">integer</a> type. Negative numbers may be used with signed
985 integer types.
986 </dd>
987
988 <dt><b>Floating point constants</b></dt>
989
990 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
991 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]992 notation (see below). Floating point constants must have a <a
993 href="#t_floating">floating point</a> type. </dd>
994
995 <dt><b>Null pointer constants</b></dt>
996
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]997 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]998 and must be of <a href="#t_pointer">pointer type</a>.</dd>
999
1000</dl>
1001
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1002<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1003of floating point constants. For example, the form '<tt>double
10040x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
10054.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1006(and the only time that they are generated by the disassembler) is when a
1007floating point constant must be emitted but it cannot be represented as a
1008decimal floating point number. For example, NaN's, infinities, and other
1009special values are represented in their IEEE hexadecimal format so that
1010assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1011
1012</div>
1013
1014<!-- ======================================================================= -->
1015<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1016</div>
1017
1018<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1019<p>Aggregate constants arise from aggregation of simple constants
1020and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1021
1022<dl>
1023 <dt><b>Structure constants</b></dt>
1024
1025 <dd>Structure constants are represented with notation similar to structure
1026 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1027 (<tt>{}</tt>)). For example: "<tt>{ int 4, float 17.0, int* %G }</tt>",
1028 where "<tt>%G</tt>" is declared as "<tt>%G = external global int</tt>". Structure constants
1029 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1030 types of elements must match those specified by the type.
1031 </dd>
1032
1033 <dt><b>Array constants</b></dt>
1034
1035 <dd>Array constants are represented with notation similar to array type
1036 definitions (a comma separated list of elements, surrounded by square brackets
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1037 (<tt>[]</tt>)). For example: "<tt>[ int 42, int 11, int 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1038 constants must have <a href="#t_array">array type</a>, and the number and
1039 types of elements must match those specified by the type.
1040 </dd>
1041
1042 <dt><b>Packed constants</b></dt>
1043
1044 <dd>Packed constants are represented with notation similar to packed type
1045 definitions (a comma separated list of elements, surrounded by
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1046 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]1047 int 11, int 74, int 100 &gt;</tt>". Packed constants must have <a
1048 href="#t_packed">packed type</a>, and the number and types of elements must
1049 match those specified by the type.
1050 </dd>
1051
1052 <dt><b>Zero initialization</b></dt>
1053
1054 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1055 value to zero of <em>any</em> type, including scalar and aggregate types.
1056 This is often used to avoid having to print large zero initializers (e.g. for
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1057 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1058 initializers.
1059 </dd>
1060</dl>
1061
1062</div>
1063
1064<!-- ======================================================================= -->
1065<div class="doc_subsection">
1066 <a name="globalconstants">Global Variable and Function Addresses</a>
1067</div>
1068
1069<div class="doc_text">
1070
1071<p>The addresses of <a href="#globalvars">global variables</a> and <a
1072href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1073constants. These constants are explicitly referenced when the <a
1074href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1075href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1076file:</p>
1077
1078<pre>
1079 %X = global int 17
1080 %Y = global int 42
1081 %Z = global [2 x int*] [ int* %X, int* %Y ]
1082</pre>
1083
1084</div>
1085
1086<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1087<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1088<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1089 <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]1090 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1091 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1092
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1093 <p>Undefined values indicate to the compiler that the program is well defined
1094 no matter what value is used, giving the compiler more freedom to optimize.
1095 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1096</div>
1097
1098<!-- ======================================================================= -->
1099<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1100</div>
1101
1102<div class="doc_text">
1103
1104<p>Constant expressions are used to allow expressions involving other constants
1105to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1106href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1107that does not have side effects (e.g. load and call are not supported). The
1108following is the syntax for constant expressions:</p>
1109
1110<dl>
1111 <dt><b><tt>cast ( CST to TYPE )</tt></b></dt>
1112
1113 <dd>Cast a constant to another type.</dd>
1114
1115 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1116
1117 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1118 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1119 instruction, the index list may have zero or more indexes, which are required
1120 to make sense for the type of "CSTPTR".</dd>
1121
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1122 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1123
1124 <dd>Perform the <a href="#i_select">select operation</a> on
1125 constants.
1126
1127 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1128
1129 <dd>Perform the <a href="#i_extractelement">extractelement
1130 operation</a> on constants.
1131
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1132 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1133
1134 <dd>Perform the <a href="#i_insertelement">insertelement
1135 operation</a> on constants.
1136
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1137 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1138
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1139 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1140 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1141 binary</a> operations. The constraints on operands are the same as those for
1142 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1143 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1144</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1145</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1146
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1147<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1148<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1149<!-- *********************************************************************** -->
1150
1151<!-- ======================================================================= -->
1152<div class="doc_subsection">
1153<a name="inlineasm">Inline Assembler Expressions</a>
1154</div>
1155
1156<div class="doc_text">
1157
1158<p>
1159LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1160Module-Level Inline Assembly</a>) through the use of a special value. This
1161value represents the inline assembler as a string (containing the instructions
1162to emit), a list of operand constraints (stored as a string), and a flag that
1163indicates whether or not the inline asm expression has side effects. An example
1164inline assembler expression is:
1165</p>
1166
1167<pre>
1168 int(int) asm "bswap $0", "=r,r"
1169</pre>
1170
1171<p>
1172Inline assembler expressions may <b>only</b> be used as the callee operand of
1173a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1174</p>
1175
1176<pre>
1177 %X = call int asm "<a href="#i_bswap">bswap</a> $0", "=r,r"(int %Y)
1178</pre>
1179
1180<p>
1181Inline asms with side effects not visible in the constraint list must be marked
1182as having side effects. This is done through the use of the
1183'<tt>sideeffect</tt>' keyword, like so:
1184</p>
1185
1186<pre>
1187 call void asm sideeffect "eieio", ""()
1188</pre>
1189
1190<p>TODO: The format of the asm and constraints string still need to be
1191documented here. Constraints on what can be done (e.g. duplication, moving, etc
1192need to be documented).
1193</p>
1194
1195</div>
1196
1197<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1198<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1199<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1200
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1201<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1202
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1203<p>The LLVM instruction set consists of several different
1204classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1205instructions</a>, <a href="#binaryops">binary instructions</a>,
1206<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1207 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1208instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1209
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1210</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1211
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1212<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1213<div class="doc_subsection"> <a name="terminators">Terminator
1214Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1215
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1216<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1217
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1218<p>As mentioned <a href="#functionstructure">previously</a>, every
1219basic block in a program ends with a "Terminator" instruction, which
1220indicates which block should be executed after the current block is
1221finished. These terminator instructions typically yield a '<tt>void</tt>'
1222value: they produce control flow, not values (the one exception being
1223the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1224<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1225 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1226instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1227the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1228 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1229 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1230
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1231</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1232
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1233<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1234<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1235Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1236<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1237<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1238<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]1239 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1240</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1241<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1242<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1243value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1244<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1245returns a value and then causes control flow, and one that just causes
1246control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1247<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1248<p>The '<tt>ret</tt>' instruction may return any '<a
1249 href="#t_firstclass">first class</a>' type. Notice that a function is
1250not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1251instruction inside of the function that returns a value that does not
1252match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1253<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1254<p>When the '<tt>ret</tt>' instruction is executed, control flow
1255returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1256 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1257the instruction after the call. If the caller was an "<a
1258 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1259at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1260returns a value, that value shall set the call or invoke instruction's
1261return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1262<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1263<pre> ret int 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1264 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1265</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1266</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1267<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1268<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1269<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1270<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1271<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]1272</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1273<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1274<p>The '<tt>br</tt>' instruction is used to cause control flow to
1275transfer to a different basic block in the current function. There are
1276two forms of this instruction, corresponding to a conditional branch
1277and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1278<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1279<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1280single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1281unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1282value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1283<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1284<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1285argument is evaluated. If the value is <tt>true</tt>, control flows
1286to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1287control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1288<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1289<pre>Test:<br> %cond = <a href="#i_setcc">seteq</a> int %a, %b<br> br bool %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
1290 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]1291</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1292<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1293<div class="doc_subsubsection">
1294 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1295</div>
1296
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1297<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1298<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1299
1300<pre>
1301 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1302</pre>
1303
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1304<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1305
1306<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1307several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1308instruction, allowing a branch to occur to one of many possible
1309destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1310
1311
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1312<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1313
1314<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1315comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1316an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1317table is not allowed to contain duplicate constant entries.</p>
1318
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1319<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1320
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1321<p>The <tt>switch</tt> instruction specifies a table of values and
1322destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1323table is searched for the given value. If the value is found, control flow is
1324transfered to the corresponding destination; otherwise, control flow is
1325transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1326
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1327<h5>Implementation:</h5>
1328
1329<p>Depending on properties of the target machine and the particular
1330<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1331ways. For example, it could be generated as a series of chained conditional
1332branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1333
1334<h5>Example:</h5>
1335
1336<pre>
1337 <i>; Emulate a conditional br instruction</i>
1338 %Val = <a href="#i_cast">cast</a> bool %value to int
1339 switch int %Val, label %truedest [int 0, label %falsedest ]
1340
1341 <i>; Emulate an unconditional br instruction</i>
1342 switch uint 0, label %dest [ ]
1343
1344 <i>; Implement a jump table:</i>
1345 switch uint %val, label %otherwise [ uint 0, label %onzero
1346 uint 1, label %onone
1347 uint 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1348</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1349</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1350
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1351<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1352<div class="doc_subsubsection">
1353 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1354</div>
1355
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1356<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1357
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1358<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1359
1360<pre>
1361 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] &lt;ptr to function ty&gt; %&lt;function ptr val&gt;(&lt;function args&gt;)
1362 to label &lt;normal label&gt; except label &lt;exception label&gt;
1363</pre>
1364
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1365<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1366
1367<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1368function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1369'<tt>normal</tt>' label or the
1370'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1371"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1372"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1373href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1374continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1375
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1376<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1377
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1378<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1379
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1380<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1381 <li>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1382 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1383 convention</a> the call should use. If none is specified, the call defaults
1384 to using C calling conventions.
1385 </li>
1386 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1387 function value being invoked. In most cases, this is a direct function
1388 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1389 an arbitrary pointer to function value.
1390 </li>
1391
1392 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1393 function to be invoked. </li>
1394
1395 <li>'<tt>function args</tt>': argument list whose types match the function
1396 signature argument types. If the function signature indicates the function
1397 accepts a variable number of arguments, the extra arguments can be
1398 specified. </li>
1399
1400 <li>'<tt>normal label</tt>': the label reached when the called function
1401 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1402
1403 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1404 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1405
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1406</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1407
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1408<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1409
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1410<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1411href="#i_call">call</a></tt>' instruction in most regards. The primary
1412difference is that it establishes an association with a label, which is used by
1413the runtime library to unwind the stack.</p>
1414
1415<p>This instruction is used in languages with destructors to ensure that proper
1416cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1417exception. Additionally, this is important for implementation of
1418'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1419
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1420<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1421<pre>
1422 %retval = invoke int %Test(int 15) to label %Continue
1423 except label %TestCleanup <i>; {int}:retval set</i>
1424 %retval = invoke <a href="#callingconv">coldcc</a> int %Test(int 15) to label %Continue
1425 except label %TestCleanup <i>; {int}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1426</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1427</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1428
1429
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1430<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1431
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1432<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1433Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1434
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1435<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1436
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1437<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1438<pre>
1439 unwind
1440</pre>
1441
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1442<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1443
1444<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1445at the first callee in the dynamic call stack which used an <a
1446href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1447primarily used to implement exception handling.</p>
1448
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1449<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1450
1451<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1452immediately halt. The dynamic call stack is then searched for the first <a
1453href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1454execution continues at the "exceptional" destination block specified by the
1455<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1456dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1457</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1458
1459<!-- _______________________________________________________________________ -->
1460
1461<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1462Instruction</a> </div>
1463
1464<div class="doc_text">
1465
1466<h5>Syntax:</h5>
1467<pre>
1468 unreachable
1469</pre>
1470
1471<h5>Overview:</h5>
1472
1473<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1474instruction is used to inform the optimizer that a particular portion of the
1475code is not reachable. This can be used to indicate that the code after a
1476no-return function cannot be reached, and other facts.</p>
1477
1478<h5>Semantics:</h5>
1479
1480<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1481</div>
1482
1483
1484
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1485<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1486<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1487<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1488<p>Binary operators are used to do most of the computation in a
1489program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1490produce a single value. The operands might represent
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1491multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1492The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1493necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1494<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1495</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1496<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1497<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1498Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1499<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1500<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1501<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]1502</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1503<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1504<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1505<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1506<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1507 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1508 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1509Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1510<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1511<p>The value produced is the integer or floating point sum of the two
1512operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1513<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1514<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]1515</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1516</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1517<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1518<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1519Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1520<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1521<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1522<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]1523</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1524<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1525<p>The '<tt>sub</tt>' instruction returns the difference of its two
1526operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1527<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1528instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1529<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1530<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1531 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1532values.
1533This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1534Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1535<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1536<p>The value produced is the integer or floating point difference of
1537the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1538<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1539<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]1540 &lt;result&gt; = sub int 0, %val <i>; yields {int}:result = -%var</i>
1541</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1542</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1543<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1544<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1545Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1546<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1547<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1548<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]1549</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1550<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1551<p>The '<tt>mul</tt>' instruction returns the product of its two
1552operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1553<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1554<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1555 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1556values.
1557This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1558Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1559<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1560<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1561two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1562<p>There is no signed vs unsigned multiplication. The appropriate
1563action is taken based on the type of the operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1564<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1565<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]1566</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1567</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1568<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1569<div class="doc_subsubsection"> <a name="i_div">'<tt>div</tt>'
1570Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1571<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1572<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1573<pre> &lt;result&gt; = div &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1574</pre>
1575<h5>Overview:</h5>
1576<p>The '<tt>div</tt>' instruction returns the quotient of its two
1577operands.</p>
1578<h5>Arguments:</h5>
1579<p>The two arguments to the '<tt>div</tt>' instruction must be either <a
1580 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1581values.
1582This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1583Both arguments must have identical types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1584<h5>Semantics:</h5>
1585<p>The value produced is the integer or floating point quotient of the
1586two operands.</p>
1587<h5>Example:</h5>
1588<pre> &lt;result&gt; = div int 4, %var <i>; yields {int}:result = 4 / %var</i>
1589</pre>
1590</div>
1591<!-- _______________________________________________________________________ -->
1592<div class="doc_subsubsection"> <a name="i_rem">'<tt>rem</tt>'
1593Instruction</a> </div>
1594<div class="doc_text">
1595<h5>Syntax:</h5>
1596<pre> &lt;result&gt; = rem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1597</pre>
1598<h5>Overview:</h5>
1599<p>The '<tt>rem</tt>' instruction returns the remainder from the
1600division of its two operands.</p>
1601<h5>Arguments:</h5>
1602<p>The two arguments to the '<tt>rem</tt>' instruction must be either <a
1603 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1604values.
1605This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1606Both arguments must have identical types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1607<h5>Semantics:</h5>
1608<p>This returns the <i>remainder</i> of a division (where the result
1609has the same sign as the divisor), not the <i>modulus</i> (where the
1610result has the same sign as the dividend) of a value. For more
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1611information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1612 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1613Math Forum</a>.</p>
1614<h5>Example:</h5>
1615<pre> &lt;result&gt; = rem int 4, %var <i>; yields {int}:result = 4 % %var</i>
1616</pre>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]1617
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1618</div>
1619<!-- _______________________________________________________________________ -->
1620<div class="doc_subsubsection"> <a name="i_setcc">'<tt>set<i>cc</i></tt>'
1621Instructions</a> </div>
1622<div class="doc_text">
1623<h5>Syntax:</h5>
1624<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]1625 &lt;result&gt; = setne &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1626 &lt;result&gt; = setlt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1627 &lt;result&gt; = setgt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1628 &lt;result&gt; = setle &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1629 &lt;result&gt; = setge &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1630</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1631<h5>Overview:</h5>
1632<p>The '<tt>set<i>cc</i></tt>' family of instructions returns a boolean
1633value based on a comparison of their two operands.</p>
1634<h5>Arguments:</h5>
1635<p>The two arguments to the '<tt>set<i>cc</i></tt>' instructions must
1636be of <a href="#t_firstclass">first class</a> type (it is not possible
1637to compare '<tt>label</tt>'s, '<tt>array</tt>'s, '<tt>structure</tt>'
1638or '<tt>void</tt>' values, etc...). Both arguments must have identical
1639types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1640<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1641<p>The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1642value if both operands are equal.<br>
1643The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1644value if both operands are unequal.<br>
1645The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1646value if the first operand is less than the second operand.<br>
1647The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1648value if the first operand is greater than the second operand.<br>
1649The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1650value if the first operand is less than or equal to the second operand.<br>
1651The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1652value if the first operand is greater than or equal to the second
1653operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1654<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1655<pre> &lt;result&gt; = seteq int 4, 5 <i>; yields {bool}:result = false</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1656 &lt;result&gt; = setne float 4, 5 <i>; yields {bool}:result = true</i>
1657 &lt;result&gt; = setlt uint 4, 5 <i>; yields {bool}:result = true</i>
1658 &lt;result&gt; = setgt sbyte 4, 5 <i>; yields {bool}:result = false</i>
1659 &lt;result&gt; = setle sbyte 4, 5 <i>; yields {bool}:result = true</i>
1660 &lt;result&gt; = setge sbyte 4, 5 <i>; yields {bool}:result = false</i>
1661</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1662</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]1663
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1664<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1665<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1666Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1667<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1668<p>Bitwise binary operators are used to do various forms of
1669bit-twiddling in a program. They are generally very efficient
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1670instructions and can commonly be strength reduced from other
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1671instructions. They require two operands, execute an operation on them,
1672and produce a single value. The resulting value of the bitwise binary
1673operators is always the same type as its first operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1674</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1675<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1676<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1677Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1678<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1679<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1680<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]1681</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1682<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1683<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1684its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1685<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1686<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1687 href="#t_integral">integral</a> values. Both arguments must have
1688identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1689<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1690<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1691<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1692<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1693<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1694 <tbody>
1695 <tr>
1696 <td>In0</td>
1697 <td>In1</td>
1698 <td>Out</td>
1699 </tr>
1700 <tr>
1701 <td>0</td>
1702 <td>0</td>
1703 <td>0</td>
1704 </tr>
1705 <tr>
1706 <td>0</td>
1707 <td>1</td>
1708 <td>0</td>
1709 </tr>
1710 <tr>
1711 <td>1</td>
1712 <td>0</td>
1713 <td>0</td>
1714 </tr>
1715 <tr>
1716 <td>1</td>
1717 <td>1</td>
1718 <td>1</td>
1719 </tr>
1720 </tbody>
1721</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1722</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1723<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1724<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]1725 &lt;result&gt; = and int 15, 40 <i>; yields {int}:result = 8</i>
1726 &lt;result&gt; = and int 4, 8 <i>; yields {int}:result = 0</i>
1727</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1728</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1729<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1730<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1731<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1732<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1733<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]1734</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1735<h5>Overview:</h5>
1736<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1737or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1738<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1739<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1740 href="#t_integral">integral</a> values. Both arguments must have
1741identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1742<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1743<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1744<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1745<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1746<table border="1" cellspacing="0" cellpadding="4">
1747 <tbody>
1748 <tr>
1749 <td>In0</td>
1750 <td>In1</td>
1751 <td>Out</td>
1752 </tr>
1753 <tr>
1754 <td>0</td>
1755 <td>0</td>
1756 <td>0</td>
1757 </tr>
1758 <tr>
1759 <td>0</td>
1760 <td>1</td>
1761 <td>1</td>
1762 </tr>
1763 <tr>
1764 <td>1</td>
1765 <td>0</td>
1766 <td>1</td>
1767 </tr>
1768 <tr>
1769 <td>1</td>
1770 <td>1</td>
1771 <td>1</td>
1772 </tr>
1773 </tbody>
1774</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1775</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1776<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1777<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]1778 &lt;result&gt; = or int 15, 40 <i>; yields {int}:result = 47</i>
1779 &lt;result&gt; = or int 4, 8 <i>; yields {int}:result = 12</i>
1780</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1781</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1782<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1783<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
1784Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1785<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1786<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1787<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]1788</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1789<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1790<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
1791or of its two operands. The <tt>xor</tt> is used to implement the
1792"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1793<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1794<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1795 href="#t_integral">integral</a> values. Both arguments must have
1796identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1797<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1798<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1799<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1800<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1801<table border="1" cellspacing="0" cellpadding="4">
1802 <tbody>
1803 <tr>
1804 <td>In0</td>
1805 <td>In1</td>
1806 <td>Out</td>
1807 </tr>
1808 <tr>
1809 <td>0</td>
1810 <td>0</td>
1811 <td>0</td>
1812 </tr>
1813 <tr>
1814 <td>0</td>
1815 <td>1</td>
1816 <td>1</td>
1817 </tr>
1818 <tr>
1819 <td>1</td>
1820 <td>0</td>
1821 <td>1</td>
1822 </tr>
1823 <tr>
1824 <td>1</td>
1825 <td>1</td>
1826 <td>0</td>
1827 </tr>
1828 </tbody>
1829</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1830</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1831<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1832<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1833<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]1834 &lt;result&gt; = xor int 15, 40 <i>; yields {int}:result = 39</i>
1835 &lt;result&gt; = xor int 4, 8 <i>; yields {int}:result = 12</i>
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1836 &lt;result&gt; = xor int %V, -1 <i>; yields {int}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1837</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1838</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1839<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1840<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
1841Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1842<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1843<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1844<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]1845</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1846<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1847<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
1848the left a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1849<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1850<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1851 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1852type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1853<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1854<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]1855<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1856<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]1857 &lt;result&gt; = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
1858 &lt;result&gt; = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
1859</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1860</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1861<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1862<div class="doc_subsubsection"> <a name="i_shr">'<tt>shr</tt>'
1863Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1864<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1865<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1866<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]1867</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1868<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1869<p>The '<tt>shr</tt>' instruction returns the first operand shifted to
1870the right a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1871<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1872<p>The first argument to the '<tt>shr</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1873 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1874type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1875<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1876<p>If the first argument is a <a href="#t_signed">signed</a> type, the
1877most significant bit is duplicated in the newly free'd bit positions.
1878If the first argument is unsigned, zero bits shall fill the empty
1879positions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1880<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1881<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]1882 &lt;result&gt; = shr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1883 &lt;result&gt; = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
Chris Lattner8c6bb902003-06-18 21:30:51 +0000[diff] [blame]1884 &lt;result&gt; = shr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i>
1885 &lt;result&gt; = shr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1886</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1887</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1888
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1889<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1890<div class="doc_subsection">
1891 <a name="memoryops">Memory Access Operations</a>
1892</div>
1893
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1894<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1895
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1896<p>A key design point of an SSA-based representation is how it
1897represents memory. In LLVM, no memory locations are in SSA form, which
1898makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1899allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1900
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1901</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1902
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1903<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1904<div class="doc_subsubsection">
1905 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
1906</div>
1907
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1908<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1909
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1910<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1911
1912<pre>
1913 &lt;result&gt; = malloc &lt;type&gt;[, uint &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1914</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1915
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1916<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1917
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1918<p>The '<tt>malloc</tt>' instruction allocates memory from the system
1919heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1920
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1921<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1922
1923<p>The '<tt>malloc</tt>' instruction allocates
1924<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]1925bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1926appropriate type to the program. If "NumElements" is specified, it is the
1927number of elements allocated. If an alignment is specified, the value result
1928of the allocation is guaranteed to be aligned to at least that boundary. If
1929not specified, or if zero, the target can choose to align the allocation on any
1930convenient boundary.</p>
1931
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1932<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1933
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1934<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1935
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1936<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
1937a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1938
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1939<h5>Example:</h5>
1940
1941<pre>
1942 %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
1943
1944 %size = <a 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]1945 %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i>
1946 %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1947 %array3 = malloc int, uint 4, align 1024 <i>; yields {int*}:array3</i>
1948 %array4 = malloc int, align 1024 <i>; yields {int*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1949</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1950</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1951
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1952<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1953<div class="doc_subsubsection">
1954 <a name="i_free">'<tt>free</tt>' Instruction</a>
1955</div>
1956
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1957<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1958
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1959<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1960
1961<pre>
1962 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1963</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1964
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1965<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1966
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1967<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1968memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1969
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1970<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1971
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1972<p>'<tt>value</tt>' shall be a pointer value that points to a value
1973that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
1974instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1975
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1976<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1977
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1978<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1979after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1980
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1981<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1982
1983<pre>
1984 %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]1985 free [4 x ubyte]* %array
1986</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1987</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1988
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1989<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1990<div class="doc_subsubsection">
1991 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
1992</div>
1993
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1994<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1995
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1996<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]1997
1998<pre>
1999 &lt;result&gt; = alloca &lt;type&gt;[, uint &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2000</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2001
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2002<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2003
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2004<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2005stack frame of the procedure that is live until the current function
2006returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2007
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2008<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2009
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2010<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2011bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2012appropriate type to the program. If "NumElements" is specified, it is the
2013number of elements allocated. If an alignment is specified, the value result
2014of the allocation is guaranteed to be aligned to at least that boundary. If
2015not specified, or if zero, the target can choose to align the allocation on any
2016convenient boundary.</p>
2017
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2018<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2019
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2020<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2021
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2022<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2023memory is automatically released when the function returns. The '<tt>alloca</tt>'
2024instruction is commonly used to represent automatic variables that must
2025have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2026 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]2027instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2028
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2029<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2030
2031<pre>
2032 %ptr = alloca int <i>; yields {int*}:ptr</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2033 %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2034 %ptr = alloca int, uint 4, align 1024 <i>; yields {int*}:ptr</i>
2035 %ptr = alloca int, align 1024 <i>; yields {int*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2036</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2037</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2038
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2039<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2040<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2041Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2042<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2043<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2044<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]2045<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2046<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2047<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2048<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2049address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2050 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2051marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2052the number or order of execution of this <tt>load</tt> with other
2053volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2054instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2055<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2056<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2057<h5>Examples:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2058<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
2059 <a
2060 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2061 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
2062</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2063</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2064<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2065<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2066Instruction</a> </div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2067<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2068<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]2069 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]2070</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2071<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2072<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2073<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2074<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2075to store and an address in which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2076operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2077operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2078optimizer is not allowed to modify the number or order of execution of
2079this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2080 href="#i_store">store</a></tt> instructions.</p>
2081<h5>Semantics:</h5>
2082<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2083at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2084<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2085<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
2086 <a
2087 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2088 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
2089</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2090<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2091<div class="doc_subsubsection">
2092 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2093</div>
2094
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2095<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2096<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2097<pre>
2098 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2099</pre>
2100
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2101<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2102
2103<p>
2104The '<tt>getelementptr</tt>' instruction is used to get the address of a
2105subelement of an aggregate data structure.</p>
2106
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2107<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2108
2109<p>This instruction takes a list of integer constants that indicate what
2110elements of the aggregate object to index to. The actual types of the arguments
2111provided depend on the type of the first pointer argument. The
2112'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2113levels of a structure or to a specific index in an array. When indexing into a
2114structure, only <tt>uint</tt>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2115integer constants are allowed. When indexing into an array or pointer,
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2116<tt>int</tt> and <tt>long</tt> indexes are allowed of any sign.</p>
2117
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2118<p>For example, let's consider a C code fragment and how it gets
2119compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2120
2121<pre>
2122 struct RT {
2123 char A;
2124 int B[10][20];
2125 char C;
2126 };
2127 struct ST {
2128 int X;
2129 double Y;
2130 struct RT Z;
2131 };
2132
2133 int *foo(struct ST *s) {
2134 return &amp;s[1].Z.B[5][13];
2135 }
2136</pre>
2137
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2138<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2139
2140<pre>
2141 %RT = type { sbyte, [10 x [20 x int]], sbyte }
2142 %ST = type { int, double, %RT }
2143
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2144 implementation
2145
2146 int* %foo(%ST* %s) {
2147 entry:
2148 %reg = getelementptr %ST* %s, int 1, uint 2, uint 1, int 5, int 13
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2149 ret int* %reg
2150 }
2151</pre>
2152
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2153<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2154
2155<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2156on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2157and <a href="#t_array">array</a> types require <tt>uint</tt>, <tt>int</tt>,
2158<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]2159types require <tt>uint</tt> <b>constants</b>.</p>
2160
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2161<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]2162type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT
2163}</tt>' type, a structure. The second index indexes into the third element of
2164the structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]],
2165sbyte }</tt>' type, another structure. The third index indexes into the second
2166element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an
2167array. The two dimensions of the array are subscripted into, yielding an
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2168'<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2169to this element, thus computing a value of '<tt>int*</tt>' type.</p>
2170
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2171<p>Note that it is perfectly legal to index partially through a
2172structure, returning a pointer to an inner element. Because of this,
2173the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2174
2175<pre>
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]2176 int* %foo(%ST* %s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2177 %t1 = getelementptr %ST* %s, int 1 <i>; yields %ST*:%t1</i>
2178 %t2 = getelementptr %ST* %t1, int 0, uint 2 <i>; yields %RT*:%t2</i>
2179 %t3 = getelementptr %RT* %t2, int 0, uint 1 <i>; yields [10 x [20 x int]]*:%t3</i>
2180 %t4 = getelementptr [10 x [20 x int]]* %t3, int 0, int 5 <i>; yields [20 x int]*:%t4</i>
2181 %t5 = getelementptr [20 x int]* %t4, int 0, int 13 <i>; yields int*:%t5</i>
2182 ret int* %t5
2183 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2184</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2185
2186<p>Note that it is undefined to access an array out of bounds: array and
2187pointer indexes must always be within the defined bounds of the array type.
2188The one exception for this rules is zero length arrays. These arrays are
2189defined to be accessible as variable length arrays, which requires access
2190beyond the zero'th element.</p>
2191
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2192<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2193
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2194<pre>
2195 <i>; yields [12 x ubyte]*:aptr</i>
2196 %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, uint 1
2197</pre>
2198
2199</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2200<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2201<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2202<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]2203<p>The instructions in this category are the "miscellaneous"
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2204instructions, which defy better classification.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2205</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2206<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2207<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
2208Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2209<div class="doc_text">
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2210<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2211<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]2212<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2213<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
2214the SSA graph representing the function.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2215<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2216<p>The type of the incoming values are specified with the first type
2217field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
2218as arguments, with one pair for each predecessor basic block of the
2219current block. Only values of <a href="#t_firstclass">first class</a>
2220type may be used as the value arguments to the PHI node. Only labels
2221may be used as the label arguments.</p>
2222<p>There must be no non-phi instructions between the start of a basic
2223block and the PHI instructions: i.e. PHI instructions must be first in
2224a basic block.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2225<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2226<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
2227value specified by the parameter, depending on which basic block we
2228came from in the last <a href="#terminators">terminator</a> instruction.</p>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2229<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2230<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]2231</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2232
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2233<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2234<div class="doc_subsubsection">
2235 <a name="i_cast">'<tt>cast .. to</tt>' Instruction</a>
2236</div>
2237
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2238<div class="doc_text">
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2239
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2240<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2241
2242<pre>
2243 &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]2244</pre>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2245
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2246<h5>Overview:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2247
2248<p>
2249The '<tt>cast</tt>' instruction is used as the primitive means to convert
2250integers to floating point, change data type sizes, and break type safety (by
2251casting pointers).
2252</p>
2253
2254
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2255<h5>Arguments:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2256
2257<p>
2258The '<tt>cast</tt>' instruction takes a value to cast, which must be a first
2259class value, and a type to cast it to, which must also be a <a
2260href="#t_firstclass">first class</a> type.
2261</p>
2262
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2263<h5>Semantics:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2264
2265<p>
2266This instruction follows the C rules for explicit casts when determining how the
2267data being cast must change to fit in its new container.
2268</p>
2269
2270<p>
2271When casting to bool, any value that would be considered true in the context of
2272a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' values,
2273all else are '<tt>false</tt>'.
2274</p>
2275
2276<p>
2277When extending an integral value from a type of one signness to another (for
2278example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value is sign-extended if the
2279<b>source</b> value is signed, and zero-extended if the source value is
2280unsigned. <tt>bool</tt> values are always zero extended into either zero or
2281one.
2282</p>
2283
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2284<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2285
2286<pre>
2287 %X = cast int 257 to ubyte <i>; yields ubyte:1</i>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame]2288 %Y = cast int 123 to bool <i>; yields bool:true</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2289</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2290</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2291
2292<!-- _______________________________________________________________________ -->
2293<div class="doc_subsubsection">
2294 <a name="i_select">'<tt>select</tt>' Instruction</a>
2295</div>
2296
2297<div class="doc_text">
2298
2299<h5>Syntax:</h5>
2300
2301<pre>
2302 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
2303</pre>
2304
2305<h5>Overview:</h5>
2306
2307<p>
2308The '<tt>select</tt>' instruction is used to choose one value based on a
2309condition, without branching.
2310</p>
2311
2312
2313<h5>Arguments:</h5>
2314
2315<p>
2316The '<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.
2317</p>
2318
2319<h5>Semantics:</h5>
2320
2321<p>
2322If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2323value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2324</p>
2325
2326<h5>Example:</h5>
2327
2328<pre>
2329 %X = select bool true, ubyte 17, ubyte 42 <i>; yields ubyte:17</i>
2330</pre>
2331</div>
2332
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2333<!-- _______________________________________________________________________ -->
2334<div class="doc_subsubsection"> <a name="i_vset">'<tt>vset</tt>'
2335Instruction</a> </div>
2336<div class="doc_text">
2337<h5>Syntax:</h5>
2338<pre>&lt;result&gt; = vset &lt;op&gt;, &lt;n x &lt;ty&gt;&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields &lt;n x bool&gt;</i>
2339</pre>
2340
2341<h5>Overview:</h5>
2342
2343<p>The '<tt>vset</tt>' instruction returns a vector of boolean
2344values representing, at each position, the result of the comparison
2345between the values at that position in the two operands.</p>
2346
2347<h5>Arguments:</h5>
2348
2349<p>The arguments to a '<tt>vset</tt>' instruction are a comparison
2350operation and two value arguments. The value arguments must be of <a
2351href="#t_packed">packed</a> type, and they must have identical types.
2352For value arguments of integral element type, the operation argument
2353must be one of <tt>eq</tt>, <tt>ne</tt>, <tt>lt</tt>, <tt>gt</tt>,
2354<tt>le</tt>, <tt>ge</tt>, <tt>ult</tt>, <tt>ugt</tt>, <tt>ule</tt>,
2355<tt>uge</tt>, <tt>true</tt>, and <tt>false</tt>. For value arguments
2356of floating point element type, the operation argument must be one of
2357<tt>eq</tt>, <tt>ne</tt>, <tt>lt</tt>, <tt>gt</tt>, <tt>le</tt>,
2358<tt>ge</tt>, <tt>oeq</tt>, <tt>one</tt>, <tt>olt</tt>, <tt>ogt</tt>,
2359<tt>ole</tt>, <tt>oge</tt>, <tt>ueq</tt>, <tt>une</tt>, <tt>ult</tt>,
2360<tt>ugt</tt>, <tt>ule</tt>, <tt>uge</tt>, <tt>o</tt>, <tt>u</tt>,
2361<tt>true</tt>, and <tt>false</tt>. The result is a packed
2362<tt>bool</tt> value with the same length as each operand.</p>
2363
2364<h5>Semantics:</h5>
2365
2366<p>The following table shows the semantics of '<tt>vset</tt>' for
2367integral value arguments. For each position of the result, the
2368comparison is done on the corresponding positions of the two value
2369arguments. Note that the signedness of the comparison depends on the
2370comparison opcode and <i>not</i> on the signedness of the value
2371operands. E.g., <tt>vset lt <4 x unsigned> %x, %y</tt> does an
2372elementwise <i>signed</i> comparison of <tt>%x</tt> and
2373<tt>%y</tt>.</p>
2374
2375<table border="1" cellspacing="0" cellpadding="4">
2376 <tbody>
2377 <tr><th>Operation</th><th>Result is true iff</th><th>Comparison is</th></tr>
2378 <tr><td><tt>eq</tt></td><td>var1 == var2</td><td>--</td></tr>
2379 <tr><td><tt>ne</tt></td><td>var1 != var2</td><td>--</td></tr>
2380 <tr><td><tt>lt</tt></td><td>var1 &lt; var2</td><td>signed</td></tr>
2381 <tr><td><tt>gt</tt></td><td>var1 &gt; var2</td><td>signed</td></tr>
2382 <tr><td><tt>le</tt></td><td>var1 &lt;= var2</td><td>signed</td></tr>
2383 <tr><td><tt>ge</tt></td><td>var1 &gt;= var2</td><td>signed</td></tr>
2384 <tr><td><tt>ult</tt></td><td>var1 &lt; var2</td><td>unsigned</td></tr>
2385 <tr><td><tt>ugt</tt></td><td>var1 &gt; var2</td><td>unsigned</td></tr>
2386 <tr><td><tt>ule</tt></td><td>var1 &lt;= var2</td><td>unsigned</td></tr>
2387 <tr><td><tt>uge</tt></td><td>var1 &gt;= var2</td><td>unsigned</td></tr>
2388 <tr><td><tt>true</tt></td><td>always</td><td>--</td></tr>
2389 <tr><td><tt>false</tt></td><td>never</td><td>--</td></tr>
2390 </tbody>
2391</table>
2392
2393<p>The following table shows the semantics of '<tt>vset</tt>' for
2394floating point types. If either operand is a floating point Not a
2395Number (NaN) value, the operation is unordered, and the value in the
2396first column below is produced at that position. Otherwise, the
2397operation is ordered, and the value in the second column is
2398produced.</p>
2399
2400<table border="1" cellspacing="0" cellpadding="4">
2401 <tbody>
2402 <tr><th>Operation</th><th>If unordered<th>Otherwise true iff</th></tr>
2403 <tr><td><tt>eq</tt></td><td>undefined</td><td>var1 == var2</td></tr>
2404 <tr><td><tt>ne</tt></td><td>undefined</td><td>var1 != var2</td></tr>
2405 <tr><td><tt>lt</tt></td><td>undefined</td><td>var1 &lt; var2</td></tr>
2406 <tr><td><tt>gt</tt></td><td>undefined</td><td>var1 &gt; var2</td></tr>
2407 <tr><td><tt>le</tt></td><td>undefined</td><td>var1 &lt;= var2</td></tr>
2408 <tr><td><tt>ge</tt></td><td>undefined</td><td>var1 &gt;= var2</td></tr>
2409 <tr><td><tt>oeq</tt></td><td>false</td><td>var1 == var2</td></tr>
2410 <tr><td><tt>one</tt></td><td>false</td><td>var1 != var2</td></tr>
2411 <tr><td><tt>olt</tt></td><td>false</td><td>var1 &lt; var2</td></tr>
2412 <tr><td><tt>ogt</tt></td><td>false</td><td>var1 &gt; var2</td></tr>
2413 <tr><td><tt>ole</tt></td><td>false</td><td>var1 &lt;= var2</td></tr>
2414 <tr><td><tt>oge</tt></td><td>false</td><td>var1 &gt;= var2</td></tr>
2415 <tr><td><tt>ueq</tt></td><td>true</td><td>var1 == var2</td></tr>
2416 <tr><td><tt>une</tt></td><td>true</td><td>var1 != var2</td></tr>
2417 <tr><td><tt>ult</tt></td><td>true</td><td>var1 &lt; var2</td></tr>
2418 <tr><td><tt>ugt</tt></td><td>true</td><td>var1 &gt; var2</td></tr>
2419 <tr><td><tt>ule</tt></td><td>true</td><td>var1 &lt;= var2</td></tr>
2420 <tr><td><tt>uge</tt></td><td>true</td><td>var1 &gt;= var2</td></tr>
2421 <tr><td><tt>o</tt></td><td>false</td><td>always</td></tr>
2422 <tr><td><tt>u</tt></td><td>true</td><td>never</td></tr>
2423 <tr><td><tt>true</tt></td><td>true</td><td>always</td></tr>
2424 <tr><td><tt>false</tt></td><td>false</td><td>never</td></tr>
2425 </tbody>
2426</table>
2427
2428<h5>Example:</h5>
2429<pre> &lt;result&gt; = vset eq &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = false, false</i>
2430 &lt;result&gt; = vset ne &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = true, true</i>
2431 &lt;result&gt; = vset lt &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = true, false</i>
2432 &lt;result&gt; = vset gt &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = false, true</i>
2433 &lt;result&gt; = vset le &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = true, false</i>
2434 &lt;result&gt; = vset ge &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = false, true</i>
2435</pre>
2436</div>
2437
2438<!-- _______________________________________________________________________ -->
2439<div class="doc_subsubsection">
2440 <a name="i_vselect">'<tt>vselect</tt>' Instruction</a>
2441</div>
2442
2443<div class="doc_text">
2444
2445<h5>Syntax:</h5>
2446
2447<pre>
2448 &lt;result&gt; = vselect &lt;n x bool&gt; &lt;cond&gt;, &lt;n x &lt;ty&gt;&gt; &lt;val1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;val2&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
2449</pre>
2450
2451<h5>Overview:</h5>
2452
2453<p>
2454The '<tt>vselect</tt>' instruction chooses one value at each position
2455of a vector based on a condition.
2456</p>
2457
2458
2459<h5>Arguments:</h5>
2460
2461<p>
2462The '<tt>vselect</tt>' instruction requires a <a
2463href="#t_packed">packed</a> <tt>bool</tt> value indicating the
2464condition at each vector position, and two values of the same packed
2465type. All three operands must have the same length. The type of the
2466result is the same as the type of the two value operands.</p>
2467
2468<h5>Semantics:</h5>
2469
2470<p>
2471At each position where the <tt>bool</tt> vector is true, that position
2472of the result gets its value from the first value argument; otherwise,
2473it gets its value from the second value argument.
2474</p>
2475
2476<h5>Example:</h5>
2477
2478<pre>
2479 %X = vselect bool &lt;2 x bool&gt; &lt;bool true, bool false&gt;, &lt;2 x ubyte&gt; &lt;ubyte 17, ubyte 17&gt;,
2480 &lt;2 x ubyte&gt; &lt;ubyte 42, ubyte 42&gt; <i>; yields &lt;2 x ubyte&gt;:17, 42</i>
2481</pre>
2482</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2483
Robert Bocchino3a558662006-01-05 17:37:02 +0000[diff] [blame]2484<!-- _______________________________________________________________________ -->
2485<div class="doc_subsubsection">
2486 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2487</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2488
Robert Bocchino3a558662006-01-05 17:37:02 +0000[diff] [blame]2489<div class="doc_text">
2490
2491<h5>Syntax:</h5>
2492
2493<pre>
2494 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, uint &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
2495</pre>
2496
2497<h5>Overview:</h5>
2498
2499<p>
2500The '<tt>extractelement</tt>' instruction extracts a single scalar
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2501element from a packed vector at a specified index.
Robert Bocchino3a558662006-01-05 17:37:02 +0000[diff] [blame]2502</p>
2503
2504
2505<h5>Arguments:</h5>
2506
2507<p>
2508The first operand of an '<tt>extractelement</tt>' instruction is a
2509value of <a href="#t_packed">packed</a> type. The second operand is
2510an index indicating the position from which to extract the element.
2511The index may be a variable.</p>
2512
2513<h5>Semantics:</h5>
2514
2515<p>
2516The result is a scalar of the same type as the element type of
2517<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2518<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2519results are undefined.
2520</p>
2521
2522<h5>Example:</h5>
2523
2524<pre>
2525 %result = extractelement &lt;4 x int&gt; %vec, uint 0 <i>; yields int</i>
2526</pre>
2527</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2528
2529
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2530<!-- _______________________________________________________________________ -->
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2531<div class="doc_subsubsection">
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2532 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2533</div>
2534
2535<div class="doc_text">
2536
2537<h5>Syntax:</h5>
2538
2539<pre>
2540 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt, uint &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
2541</pre>
2542
2543<h5>Overview:</h5>
2544
2545<p>
2546The '<tt>insertelement</tt>' instruction inserts a scalar
2547element into a packed vector at a specified index.
2548</p>
2549
2550
2551<h5>Arguments:</h5>
2552
2553<p>
2554The first operand of an '<tt>insertelement</tt>' instruction is a
2555value of <a href="#t_packed">packed</a> type. The second operand is a
2556scalar value whose type must equal the element type of the first
2557operand. The third operand is an index indicating the position at
2558which to insert the value. The index may be a variable.</p>
2559
2560<h5>Semantics:</h5>
2561
2562<p>
2563The result is a packed vector of the same type as <tt>val</tt>. Its
2564element values are those of <tt>val</tt> except at position
2565<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2566exceeds the length of <tt>val</tt>, the results are undefined.
2567</p>
2568
2569<h5>Example:</h5>
2570
2571<pre>
2572 %result = insertelement &lt;4 x int&gt; %vec, int 1, uint 0 <i>; yields &lt;4 x int&gt;</i>
2573</pre>
2574</div>
2575
2576
2577<!-- _______________________________________________________________________ -->
2578<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2579 <a name="i_call">'<tt>call</tt>' Instruction</a>
2580</div>
2581
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2582<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2583
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2584<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2585<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2586 &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]2587</pre>
2588
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2589<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2590
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2591<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2592
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2593<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2594
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2595<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2596
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2597<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2598 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2599 <p>The optional "tail" marker indicates whether the callee function accesses
2600 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2601 function call is eligible for tail call optimization. Note that calls may
2602 be marked "tail" even if they do not occur before a <a
2603 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2604 </li>
2605 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2606 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
2607 convention</a> the call should use. If none is specified, the call defaults
2608 to using C calling conventions.
2609 </li>
2610 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2611 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
2612 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2613 signature. This type can be omitted if the function is not varargs and
2614 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2615 </li>
2616 <li>
2617 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
2618 be invoked. In most cases, this is a direct function invocation, but
2619 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2620 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2621 </li>
2622 <li>
2623 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]2624 function signature argument types. All arguments must be of
2625 <a href="#t_firstclass">first class</a> type. If the function signature
2626 indicates the function accepts a variable number of arguments, the extra
2627 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2628 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2629</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2630
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2631<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2632
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2633<p>The '<tt>call</tt>' instruction is used to cause control flow to
2634transfer to a specified function, with its incoming arguments bound to
2635the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
2636instruction in the called function, control flow continues with the
2637instruction after the function call, and the return value of the
2638function is bound to the result argument. This is a simpler case of
2639the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2640
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2641<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2642
2643<pre>
2644 %retval = call int %test(int %argc)
2645 call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42);
2646 %X = tail call int %foo()
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2647 %Y = tail call <a href="#callingconv">fastcc</a> int %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2648</pre>
2649
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2650</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2651
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2652<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2653<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]2654 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2655</div>
2656
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2657<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2658
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2659<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2660
2661<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2662 &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]2663</pre>
2664
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2665<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2666
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2667<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2668the "variable argument" area of a function call. It is used to implement the
2669<tt>va_arg</tt> macro in C.</p>
2670
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2671<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2672
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2673<p>This instruction takes a <tt>va_list*</tt> value and the type of
2674the argument. It returns a value of the specified argument type and
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]2675increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2676actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2677
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2678<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2679
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2680<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
2681type from the specified <tt>va_list</tt> and causes the
2682<tt>va_list</tt> to point to the next argument. For more information,
2683see the variable argument handling <a href="#int_varargs">Intrinsic
2684Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2685
2686<p>It is legal for this instruction to be called in a function which does not
2687take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2688function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2689
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2690<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2691href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2692argument.</p>
2693
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2694<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2695
2696<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
2697
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2698</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2699
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2700<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2701<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
2702<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2703
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2704<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2705
2706<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2707well known names and semantics and are required to follow certain
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2708restrictions. Overall, these instructions represent an extension mechanism for
2709the LLVM language that does not require changing all of the transformations in
2710LLVM to add to the language (or the bytecode reader/writer, the parser,
2711etc...).</p>
2712
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2713<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
2714prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2715this. Intrinsic functions must always be external functions: you cannot define
2716the body of intrinsic functions. Intrinsic functions may only be used in call
2717or invoke instructions: it is illegal to take the address of an intrinsic
2718function. Additionally, because intrinsic functions are part of the LLVM
2719language, it is required that they all be documented here if any are added.</p>
2720
2721
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2722<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner590cff32005-05-11 03:35:57 +0000[diff] [blame]2723href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2724</p>
2725
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2726</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2727
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2728<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2729<div class="doc_subsection">
2730 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
2731</div>
2732
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2733<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2734
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2735<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]2736 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2737intrinsic functions. These functions are related to the similarly
2738named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2739
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2740<p>All of these functions operate on arguments that use a
2741target-specific value type "<tt>va_list</tt>". The LLVM assembly
2742language reference manual does not define what this type is, so all
2743transformations should be prepared to handle intrinsics with any type
2744used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2745
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2746<p>This example shows how the <a href="#i_vanext"><tt>vanext</tt></a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2747instruction and the variable argument handling intrinsic functions are
2748used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2749
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2750<pre>
2751int %test(int %X, ...) {
2752 ; Initialize variable argument processing
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2753 %ap = alloca sbyte*
2754 call void %<a href="#i_va_start">llvm.va_start</a>(sbyte** %ap)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2755
2756 ; Read a single integer argument
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2757 %tmp = va_arg sbyte** %ap, int
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2758
2759 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2760 %aq = alloca sbyte*
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]2761 call void %<a href="#i_va_copy">llvm.va_copy</a>(sbyte** %aq, sbyte** %ap)
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2762 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %aq)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2763
2764 ; Stop processing of arguments.
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2765 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %ap)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2766 ret int %tmp
2767}
2768</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2769</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2770
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2771<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2772<div class="doc_subsubsection">
2773 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
2774</div>
2775
2776
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2777<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2778<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2779<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]2780<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2781<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
2782<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
2783href="#i_va_arg">va_arg</a></tt>.</p>
2784
2785<h5>Arguments:</h5>
2786
2787<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
2788
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2789<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2790
2791<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
2792macro available in C. In a target-dependent way, it initializes the
2793<tt>va_list</tt> element the argument points to, so that the next call to
2794<tt>va_arg</tt> will produce the first variable argument passed to the function.
2795Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
2796last argument of the function, the compiler can figure that out.</p>
2797
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2798</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2799
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2800<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2801<div class="doc_subsubsection">
2802 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
2803</div>
2804
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2805<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2806<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2807<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]2808<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2809<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
2810which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
2811or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2812<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2813<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2814<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2815<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]2816macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
2817Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
2818 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
2819with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2820</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2821
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2822<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2823<div class="doc_subsubsection">
2824 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
2825</div>
2826
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2827<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2828
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2829<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2830
2831<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2832 declare void %llvm.va_copy(&lt;va_list&gt;* &lt;destarglist&gt;,
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]2833 &lt;va_list&gt;* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2834</pre>
2835
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2836<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2837
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2838<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
2839the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2840
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2841<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2842
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2843<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]2844The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2845
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2846
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2847<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2848
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2849<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
2850available in C. In a target-dependent way, it copies the source
2851<tt>va_list</tt> element into the destination list. This intrinsic is necessary
2852because 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]2853arbitrarily complex and require memory allocation, for example.</p>
2854
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2855</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2856
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2857<!-- ======================================================================= -->
2858<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2859 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
2860</div>
2861
2862<div class="doc_text">
2863
2864<p>
2865LLVM support for <a href="GarbageCollection.html">Accurate Garbage
2866Collection</a> requires the implementation and generation of these intrinsics.
2867These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
2868stack</a>, as well as garbage collector implementations that require <a
2869href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
2870Front-ends for type-safe garbage collected languages should generate these
2871intrinsics to make use of the LLVM garbage collectors. For more details, see <a
2872href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
2873</p>
2874</div>
2875
2876<!-- _______________________________________________________________________ -->
2877<div class="doc_subsubsection">
2878 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
2879</div>
2880
2881<div class="doc_text">
2882
2883<h5>Syntax:</h5>
2884
2885<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2886 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2887</pre>
2888
2889<h5>Overview:</h5>
2890
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2891<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]2892the code generator, and allows some metadata to be associated with it.</p>
2893
2894<h5>Arguments:</h5>
2895
2896<p>The first argument specifies the address of a stack object that contains the
2897root pointer. The second pointer (which must be either a constant or a global
2898value address) contains the meta-data to be associated with the root.</p>
2899
2900<h5>Semantics:</h5>
2901
2902<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
2903location. At compile-time, the code generator generates information to allow
2904the runtime to find the pointer at GC safe points.
2905</p>
2906
2907</div>
2908
2909
2910<!-- _______________________________________________________________________ -->
2911<div class="doc_subsubsection">
2912 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
2913</div>
2914
2915<div class="doc_text">
2916
2917<h5>Syntax:</h5>
2918
2919<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2920 declare sbyte* %llvm.gcread(sbyte** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2921</pre>
2922
2923<h5>Overview:</h5>
2924
2925<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
2926locations, allowing garbage collector implementations that require read
2927barriers.</p>
2928
2929<h5>Arguments:</h5>
2930
2931<p>The argument is the address to read from, which should be an address
2932allocated from the garbage collector.</p>
2933
2934<h5>Semantics:</h5>
2935
2936<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
2937instruction, but may be replaced with substantially more complex code by the
2938garbage collector runtime, as needed.</p>
2939
2940</div>
2941
2942
2943<!-- _______________________________________________________________________ -->
2944<div class="doc_subsubsection">
2945 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
2946</div>
2947
2948<div class="doc_text">
2949
2950<h5>Syntax:</h5>
2951
2952<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2953 declare void %llvm.gcwrite(sbyte* %P1, sbyte** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2954</pre>
2955
2956<h5>Overview:</h5>
2957
2958<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
2959locations, allowing garbage collector implementations that require write
2960barriers (such as generational or reference counting collectors).</p>
2961
2962<h5>Arguments:</h5>
2963
2964<p>The first argument is the reference to store, and the second is the heap
2965location to store to.</p>
2966
2967<h5>Semantics:</h5>
2968
2969<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
2970instruction, but may be replaced with substantially more complex code by the
2971garbage collector runtime, as needed.</p>
2972
2973</div>
2974
2975
2976
2977<!-- ======================================================================= -->
2978<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2979 <a name="int_codegen">Code Generator Intrinsics</a>
2980</div>
2981
2982<div class="doc_text">
2983<p>
2984These intrinsics are provided by LLVM to expose special features that may only
2985be implemented with code generator support.
2986</p>
2987
2988</div>
2989
2990<!-- _______________________________________________________________________ -->
2991<div class="doc_subsubsection">
2992 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
2993</div>
2994
2995<div class="doc_text">
2996
2997<h5>Syntax:</h5>
2998<pre>
Chris Lattnerfcf39d42006-01-13 01:20:27 +0000[diff] [blame]2999 declare sbyte *%llvm.returnaddress(uint &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3000</pre>
3001
3002<h5>Overview:</h5>
3003
3004<p>
3005The '<tt>llvm.returnaddress</tt>' intrinsic returns a target-specific value
3006indicating the return address of the current function or one of its callers.
3007</p>
3008
3009<h5>Arguments:</h5>
3010
3011<p>
3012The argument to this intrinsic indicates which function to return the address
3013for. Zero indicates the calling function, one indicates its caller, etc. The
3014argument is <b>required</b> to be a constant integer value.
3015</p>
3016
3017<h5>Semantics:</h5>
3018
3019<p>
3020The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3021the return address of the specified call frame, or zero if it cannot be
3022identified. The value returned by this intrinsic is likely to be incorrect or 0
3023for arguments other than zero, so it should only be used for debugging purposes.
3024</p>
3025
3026<p>
3027Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3028aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3029source-language caller.
3030</p>
3031</div>
3032
3033
3034<!-- _______________________________________________________________________ -->
3035<div class="doc_subsubsection">
3036 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3037</div>
3038
3039<div class="doc_text">
3040
3041<h5>Syntax:</h5>
3042<pre>
Chris Lattnerfcf39d42006-01-13 01:20:27 +0000[diff] [blame]3043 declare sbyte *%llvm.frameaddress(uint &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3044</pre>
3045
3046<h5>Overview:</h5>
3047
3048<p>
3049The '<tt>llvm.frameaddress</tt>' intrinsic returns the target-specific frame
3050pointer value for the specified stack frame.
3051</p>
3052
3053<h5>Arguments:</h5>
3054
3055<p>
3056The argument to this intrinsic indicates which function to return the frame
3057pointer for. Zero indicates the calling function, one indicates its caller,
3058etc. The argument is <b>required</b> to be a constant integer value.
3059</p>
3060
3061<h5>Semantics:</h5>
3062
3063<p>
3064The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3065the frame address of the specified call frame, or zero if it cannot be
3066identified. The value returned by this intrinsic is likely to be incorrect or 0
3067for arguments other than zero, so it should only be used for debugging purposes.
3068</p>
3069
3070<p>
3071Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3072aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3073source-language caller.
3074</p>
3075</div>
3076
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3077<!-- _______________________________________________________________________ -->
3078<div class="doc_subsubsection">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3079 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3080</div>
3081
3082<div class="doc_text">
3083
3084<h5>Syntax:</h5>
3085<pre>
3086 declare sbyte *%llvm.stacksave()
3087</pre>
3088
3089<h5>Overview:</h5>
3090
3091<p>
3092The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3093the function stack, for use with <a href="#i_stackrestore">
3094<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3095features like scoped automatic variable sized arrays in C99.
3096</p>
3097
3098<h5>Semantics:</h5>
3099
3100<p>
3101This intrinsic returns a opaque pointer value that can be passed to <a
3102href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
3103<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
3104<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
3105state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
3106practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
3107that were allocated after the <tt>llvm.stacksave</tt> was executed.
3108</p>
3109
3110</div>
3111
3112<!-- _______________________________________________________________________ -->
3113<div class="doc_subsubsection">
3114 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
3115</div>
3116
3117<div class="doc_text">
3118
3119<h5>Syntax:</h5>
3120<pre>
3121 declare void %llvm.stackrestore(sbyte* %ptr)
3122</pre>
3123
3124<h5>Overview:</h5>
3125
3126<p>
3127The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
3128the function stack to the state it was in when the corresponding <a
3129href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
3130useful for implementing language features like scoped automatic variable sized
3131arrays in C99.
3132</p>
3133
3134<h5>Semantics:</h5>
3135
3136<p>
3137See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
3138</p>
3139
3140</div>
3141
3142
3143<!-- _______________________________________________________________________ -->
3144<div class="doc_subsubsection">
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3145 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
3146</div>
3147
3148<div class="doc_text">
3149
3150<h5>Syntax:</h5>
3151<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3152 declare void %llvm.prefetch(sbyte * &lt;address&gt;,
3153 uint &lt;rw&gt;, uint &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3154</pre>
3155
3156<h5>Overview:</h5>
3157
3158
3159<p>
3160The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3161a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
3162no
3163effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]3164characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3165</p>
3166
3167<h5>Arguments:</h5>
3168
3169<p>
3170<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
3171determining if the fetch should be for a read (0) or write (1), and
3172<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]3173locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3174<tt>locality</tt> arguments must be constant integers.
3175</p>
3176
3177<h5>Semantics:</h5>
3178
3179<p>
3180This intrinsic does not modify the behavior of the program. In particular,
3181prefetches cannot trap and do not produce a value. On targets that support this
3182intrinsic, the prefetch can provide hints to the processor cache for better
3183performance.
3184</p>
3185
3186</div>
3187
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3188<!-- _______________________________________________________________________ -->
3189<div class="doc_subsubsection">
3190 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
3191</div>
3192
3193<div class="doc_text">
3194
3195<h5>Syntax:</h5>
3196<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3197 declare void %llvm.pcmarker( uint &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3198</pre>
3199
3200<h5>Overview:</h5>
3201
3202
3203<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3204The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
3205(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3206code to simulators and other tools. The method is target specific, but it is
3207expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3208The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]3209after optimizations. It is possible that the presence of a marker will inhibit
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3210optimizations. The intended use is to be inserted after optmizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3211correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3212</p>
3213
3214<h5>Arguments:</h5>
3215
3216<p>
3217<tt>id</tt> is a numerical id identifying the marker.
3218</p>
3219
3220<h5>Semantics:</h5>
3221
3222<p>
3223This intrinsic does not modify the behavior of the program. Backends that do not
3224support this intrinisic may ignore it.
3225</p>
3226
3227</div>
3228
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]3229<!-- _______________________________________________________________________ -->
3230<div class="doc_subsubsection">
3231 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
3232</div>
3233
3234<div class="doc_text">
3235
3236<h5>Syntax:</h5>
3237<pre>
3238 declare ulong %llvm.readcyclecounter( )
3239</pre>
3240
3241<h5>Overview:</h5>
3242
3243
3244<p>
3245The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
3246counter register (or similar low latency, high accuracy clocks) on those targets
3247that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
3248As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
3249should only be used for small timings.
3250</p>
3251
3252<h5>Semantics:</h5>
3253
3254<p>
3255When directly supported, reading the cycle counter should not modify any memory.
3256Implementations are allowed to either return a application specific value or a
3257system wide value. On backends without support, this is lowered to a constant 0.
3258</p>
3259
3260</div>
3261
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3262<!-- ======================================================================= -->
3263<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3264 <a name="int_libc">Standard C Library Intrinsics</a>
3265</div>
3266
3267<div class="doc_text">
3268<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3269LLVM provides intrinsics for a few important standard C library functions.
3270These intrinsics allow source-language front-ends to pass information about the
3271alignment of the pointer arguments to the code generator, providing opportunity
3272for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3273</p>
3274
3275</div>
3276
3277<!-- _______________________________________________________________________ -->
3278<div class="doc_subsubsection">
3279 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
3280</div>
3281
3282<div class="doc_text">
3283
3284<h5>Syntax:</h5>
3285<pre>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3286 declare void %llvm.memcpy.i32(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3287 uint &lt;len&gt;, uint &lt;align&gt;)
3288 declare void %llvm.memcpy.i64(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3289 ulong &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3290</pre>
3291
3292<h5>Overview:</h5>
3293
3294<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3295The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3296location to the destination location.
3297</p>
3298
3299<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3300Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
3301intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3302</p>
3303
3304<h5>Arguments:</h5>
3305
3306<p>
3307The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3308the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3309specifying the number of bytes to copy, and the fourth argument is the alignment
3310of the source and destination locations.
3311</p>
3312
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3313<p>
3314If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattnerf0afc2c2006-03-04 00:02:10 +0000[diff] [blame^]3315the caller guarantees that both the source and destination pointers are aligned
3316to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3317</p>
3318
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3319<h5>Semantics:</h5>
3320
3321<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3322The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3323location to the destination location, which are not allowed to overlap. It
3324copies "len" bytes of memory over. If the argument is known to be aligned to
3325some boundary, this can be specified as the fourth argument, otherwise it should
3326be set to 0 or 1.
3327</p>
3328</div>
3329
3330
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3331<!-- _______________________________________________________________________ -->
3332<div class="doc_subsubsection">
3333 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
3334</div>
3335
3336<div class="doc_text">
3337
3338<h5>Syntax:</h5>
3339<pre>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3340 declare void %llvm.memmove.i32(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3341 uint &lt;len&gt;, uint &lt;align&gt;)
3342 declare void %llvm.memmove.i64(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3343 ulong &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3344</pre>
3345
3346<h5>Overview:</h5>
3347
3348<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3349The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
3350location to the destination location. It is similar to the
3351'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3352</p>
3353
3354<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3355Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
3356intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3357</p>
3358
3359<h5>Arguments:</h5>
3360
3361<p>
3362The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3363the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3364specifying the number of bytes to copy, and the fourth argument is the alignment
3365of the source and destination locations.
3366</p>
3367
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3368<p>
3369If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattnerf0afc2c2006-03-04 00:02:10 +0000[diff] [blame^]3370the caller guarantees that the source and destination pointers are aligned to
3371that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3372</p>
3373
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3374<h5>Semantics:</h5>
3375
3376<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3377The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3378location to the destination location, which may overlap. It
3379copies "len" bytes of memory over. If the argument is known to be aligned to
3380some boundary, this can be specified as the fourth argument, otherwise it should
3381be set to 0 or 1.
3382</p>
3383</div>
3384
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3385
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3386<!-- _______________________________________________________________________ -->
3387<div class="doc_subsubsection">
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3388 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3389</div>
3390
3391<div class="doc_text">
3392
3393<h5>Syntax:</h5>
3394<pre>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3395 declare void %llvm.memset.i32(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
3396 uint &lt;len&gt;, uint &lt;align&gt;)
3397 declare void %llvm.memset.i64(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
3398 ulong &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3399</pre>
3400
3401<h5>Overview:</h5>
3402
3403<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3404The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3405byte value.
3406</p>
3407
3408<p>
3409Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
3410does not return a value, and takes an extra alignment argument.
3411</p>
3412
3413<h5>Arguments:</h5>
3414
3415<p>
3416The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3417byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3418argument specifying the number of bytes to fill, and the fourth argument is the
3419known alignment of destination location.
3420</p>
3421
3422<p>
3423If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattnerf0afc2c2006-03-04 00:02:10 +0000[diff] [blame^]3424the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3425</p>
3426
3427<h5>Semantics:</h5>
3428
3429<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3430The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
3431the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3432destination location. If the argument is known to be aligned to some boundary,
3433this can be specified as the fourth argument, otherwise it should be set to 0 or
34341.
3435</p>
3436</div>
3437
3438
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]3439<!-- _______________________________________________________________________ -->
3440<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3441 <a name="i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a>
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]3442</div>
3443
3444<div class="doc_text">
3445
3446<h5>Syntax:</h5>
3447<pre>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3448 declare bool %llvm.isunordered.f32(float Val1, float Val2)
3449 declare bool %llvm.isunordered.f64(double Val1, double Val2)
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]3450</pre>
3451
3452<h5>Overview:</h5>
3453
3454<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3455The '<tt>llvm.isunordered</tt>' intrinsics return true if either or both of the
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]3456specified floating point values is a NAN.
3457</p>
3458
3459<h5>Arguments:</h5>
3460
3461<p>
3462The arguments are floating point numbers of the same type.
3463</p>
3464
3465<h5>Semantics:</h5>
3466
3467<p>
3468If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
3469false.
3470</p>
3471</div>
3472
3473
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]3474<!-- _______________________________________________________________________ -->
3475<div class="doc_subsubsection">
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3476 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]3477</div>
3478
3479<div class="doc_text">
3480
3481<h5>Syntax:</h5>
3482<pre>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3483 declare double %llvm.sqrt.f32(float Val)
3484 declare double %llvm.sqrt.f64(double Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]3485</pre>
3486
3487<h5>Overview:</h5>
3488
3489<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3490The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]3491returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
3492<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
3493negative numbers (which allows for better optimization).
3494</p>
3495
3496<h5>Arguments:</h5>
3497
3498<p>
3499The argument and return value are floating point numbers of the same type.
3500</p>
3501
3502<h5>Semantics:</h5>
3503
3504<p>
3505This function returns the sqrt of the specified operand if it is a positive
3506floating point number.
3507</p>
3508</div>
3509
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3510<!-- ======================================================================= -->
3511<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3512 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3513</div>
3514
3515<div class="doc_text">
3516<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3517LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3518These allow efficient code generation for some algorithms.
3519</p>
3520
3521</div>
3522
3523<!-- _______________________________________________________________________ -->
3524<div class="doc_subsubsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3525 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
3526</div>
3527
3528<div class="doc_text">
3529
3530<h5>Syntax:</h5>
3531<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3532 declare ushort %llvm.bswap.i16(ushort &lt;id&gt;)
3533 declare uint %llvm.bswap.i32(uint &lt;id&gt;)
3534 declare ulong %llvm.bswap.i64(ulong &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3535</pre>
3536
3537<h5>Overview:</h5>
3538
3539<p>
3540The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
354164 bit quantity. These are useful for performing operations on data that is not
3542in the target's native byte order.
3543</p>
3544
3545<h5>Semantics:</h5>
3546
3547<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3548The <tt>llvm.bswap.16</tt> intrinsic returns a ushort value that has the high and low
3549byte of the input ushort swapped. Similarly, the <tt>llvm.bswap.i32</tt> intrinsic
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3550returns a uint value that has the four bytes of the input uint swapped, so that
3551if the input bytes are numbered 0, 1, 2, 3 then the returned uint will have its
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3552bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt> intrinsic extends this concept
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3553to 64 bits.
3554</p>
3555
3556</div>
3557
3558<!-- _______________________________________________________________________ -->
3559<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3560 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3561</div>
3562
3563<div class="doc_text">
3564
3565<h5>Syntax:</h5>
3566<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3567 declare ubyte %llvm.ctpop.i8 (ubyte &lt;src&gt;)
3568 declare ushort %llvm.ctpop.i16(ushort &lt;src&gt;)
3569 declare uint %llvm.ctpop.i32(uint &lt;src&gt;)
3570 declare ulong %llvm.ctpop.i64(ulong &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3571</pre>
3572
3573<h5>Overview:</h5>
3574
3575<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3576The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
3577value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3578</p>
3579
3580<h5>Arguments:</h5>
3581
3582<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]3583The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3584unsigned integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3585</p>
3586
3587<h5>Semantics:</h5>
3588
3589<p>
3590The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
3591</p>
3592</div>
3593
3594<!-- _______________________________________________________________________ -->
3595<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]3596 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3597</div>
3598
3599<div class="doc_text">
3600
3601<h5>Syntax:</h5>
3602<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3603 declare ubyte %llvm.ctlz.i8 (ubyte &lt;src&gt;)
3604 declare ushort %llvm.ctlz.i16(ushort &lt;src&gt;)
3605 declare uint %llvm.ctlz.i32(uint &lt;src&gt;)
3606 declare ulong %llvm.ctlz.i64(ulong &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3607</pre>
3608
3609<h5>Overview:</h5>
3610
3611<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3612The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
3613leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3614</p>
3615
3616<h5>Arguments:</h5>
3617
3618<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]3619The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3620unsigned integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3621</p>
3622
3623<h5>Semantics:</h5>
3624
3625<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3626The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
3627in a variable. If the src == 0 then the result is the size in bits of the type
3628of src. For example, <tt>llvm.cttz(int 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3629</p>
3630</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]3631
3632
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3633
3634<!-- _______________________________________________________________________ -->
3635<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]3636 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3637</div>
3638
3639<div class="doc_text">
3640
3641<h5>Syntax:</h5>
3642<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3643 declare ubyte %llvm.cttz.i8 (ubyte &lt;src&gt;)
3644 declare ushort %llvm.cttz.i16(ushort &lt;src&gt;)
3645 declare uint %llvm.cttz.i32(uint &lt;src&gt;)
3646 declare ulong %llvm.cttz.i64(ulong &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3647</pre>
3648
3649<h5>Overview:</h5>
3650
3651<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3652The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
3653trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3654</p>
3655
3656<h5>Arguments:</h5>
3657
3658<p>
3659The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3660unsigned integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3661</p>
3662
3663<h5>Semantics:</h5>
3664
3665<p>
3666The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
3667in a variable. If the src == 0 then the result is the size in bits of the type
3668of src. For example, <tt>llvm.cttz(2) = 1</tt>.
3669</p>
3670</div>
3671
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3672<!-- ======================================================================= -->
3673<div class="doc_subsection">
3674 <a name="int_debugger">Debugger Intrinsics</a>
3675</div>
3676
3677<div class="doc_text">
3678<p>
3679The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
3680are described in the <a
3681href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
3682Debugging</a> document.
3683</p>
3684</div>
3685
3686
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3687<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3688<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]3689<address>
3690 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
3691 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
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3693 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
3694
3695 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
3696 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
3697 Last modified: $Date$
3698</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3699</body>
3700</html>