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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / cc16dc3249d4484145f2d1e88c8fff8ad3822255 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
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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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]24 <li><a href="#globalvars">Global Variables</a></li>
25 <li><a href="#functionstructure">Function Structure</a></li>
26 </ol>
27 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]28 <li><a href="#typesystem">Type System</a>
29 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]30 <li><a href="#t_primitive">Primitive Types</a>
31 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]32 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]33 </ol>
34 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]35 <li><a href="#t_derived">Derived Types</a>
36 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]37 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]38 <li><a href="#t_function">Function Type</a></li>
39 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]40 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]41 <li><a href="#t_packed">Packed Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]42 </ol>
43 </li>
44 </ol>
45 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]46 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]47 <ol>
48 <li><a href="#simpleconstants">Simple Constants</a>
49 <li><a href="#aggregateconstants">Aggregate Constants</a>
50 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
51 <li><a href="#undefvalues">Undefined Values</a>
52 <li><a href="#constantexprs">Constant Expressions</a>
53 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]54 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]55 <li><a href="#instref">Instruction Reference</a>
56 <ol>
57 <li><a href="#terminators">Terminator Instructions</a>
58 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]59 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
60 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]61 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
62 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]63 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]64 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]65 </ol>
66 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]67 <li><a href="#binaryops">Binary Operations</a>
68 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]69 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
70 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
71 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
72 <li><a href="#i_div">'<tt>div</tt>' Instruction</a></li>
73 <li><a href="#i_rem">'<tt>rem</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]74 <li><a href="#i_setcc">'<tt>set<i>cc</i></tt>' Instructions</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]75 </ol>
76 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]77 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
78 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]79 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]80 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]81 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
82 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
83 <li><a href="#i_shr">'<tt>shr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]84 </ol>
85 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]86 <li><a href="#memoryops">Memory Access Operations</a>
87 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]88 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
89 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
90 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
91 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
92 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
93 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
94 </ol>
95 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]96 <li><a href="#otherops">Other Operations</a>
97 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]98 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]99 <li><a href="#i_cast">'<tt>cast .. to</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]100 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]101 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]102 <li><a href="#i_vanext">'<tt>vanext</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]103 <li><a href="#i_vaarg">'<tt>vaarg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]104 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]105 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]106 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]107 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]108 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]109 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]110 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
111 <ol>
112 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
113 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
114 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
115 </ol>
116 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]117 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
118 <ol>
119 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
120 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
121 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
122 </ol>
123 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]124 <li><a href="#int_codegen">Code Generator Intrinsics</a>
125 <ol>
126 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
127 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]128 </ol>
129 </li>
130 <li><a href="#int_os">Operating System Intrinsics</a>
131 <ol>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]132 <li><a href="#i_readport">'<tt>llvm.readport</tt>' Intrinsic</a></li>
133 <li><a href="#i_writeport">'<tt>llvm.writeport</tt>' Intrinsic</a></li>
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]134 <li><a href="#i_readio">'<tt>llvm.readio</tt>' Intrinsic</a></li>
135 <li><a href="#i_writeio">'<tt>llvm.writeio</tt>' Intrinsic</a></li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]136 </ol>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]137 <li><a href="#int_libc">Standard C Library Intrinsics</a>
138 <ol>
139 <li><a href="#i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a></li>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]140 <li><a href="#i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a></li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]141 <li><a href="#i_memset">'<tt>llvm.memset</tt>' Intrinsic</a></li>
Alkis Evlogimenos96853722004-06-12 19:19:14 +0000[diff] [blame]142 <li><a href="#i_isunordered">'<tt>llvm.isunordered</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]143 </ol>
144 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]145 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]146 </ol>
147 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]148</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]149
150<div class="doc_author">
151 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
152 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]153</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]154
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]155<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]156<div class="doc_section"> <a name="abstract">Abstract </a></div>
157<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]158
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]159<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]160<p>This document is a reference manual for the LLVM assembly language.
161LLVM is an SSA based representation that provides type safety,
162low-level operations, flexibility, and the capability of representing
163'all' high-level languages cleanly. It is the common code
164representation used throughout all phases of the LLVM compilation
165strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]166</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]167
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]168<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]169<div class="doc_section"> <a name="introduction">Introduction</a> </div>
170<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]171
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]172<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]173
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]174<p>The LLVM code representation is designed to be used in three
175different forms: as an in-memory compiler IR, as an on-disk bytecode
176representation (suitable for fast loading by a Just-In-Time compiler),
177and as a human readable assembly language representation. This allows
178LLVM to provide a powerful intermediate representation for efficient
179compiler transformations and analysis, while providing a natural means
180to debug and visualize the transformations. The three different forms
181of LLVM are all equivalent. This document describes the human readable
182representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]183
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]184<p>The LLVM representation aims to be a light-weight and low-level
185while being expressive, typed, and extensible at the same time. It
186aims to be a "universal IR" of sorts, by being at a low enough level
187that high-level ideas may be cleanly mapped to it (similar to how
188microprocessors are "universal IR's", allowing many source languages to
189be mapped to them). By providing type information, LLVM can be used as
190the target of optimizations: for example, through pointer analysis, it
191can be proven that a C automatic variable is never accessed outside of
192the current function... allowing it to be promoted to a simple SSA
193value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]194
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]195</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]196
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]197<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]198<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]199
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]200<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]201
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]202<p>It is important to note that this document describes 'well formed'
203LLVM assembly language. There is a difference between what the parser
204accepts and what is considered 'well formed'. For example, the
205following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]206
207<pre>
208 %x = <a href="#i_add">add</a> int 1, %x
209</pre>
210
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]211<p>...because the definition of <tt>%x</tt> does not dominate all of
212its uses. The LLVM infrastructure provides a verification pass that may
213be used to verify that an LLVM module is well formed. This pass is
214automatically run by the parser after parsing input assembly, and by
215the optimizer before it outputs bytecode. The violations pointed out
216by the verifier pass indicate bugs in transformation passes or input to
217the parser.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]218
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]219<!-- Describe the typesetting conventions here. --> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]220
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]221<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]222<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]223<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]224
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]225<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]226
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]227<p>LLVM uses three different forms of identifiers, for different
228purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]229
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]230<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]231 <li>Named values are represented as a string of characters with a '%' prefix.
232 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
233 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
234 Identifiers which require other characters in their names can be surrounded
235 with quotes. In this way, anything except a <tt>"</tt> character can be used
236 in a name.</li>
237
238 <li>Unnamed values are represented as an unsigned numeric value with a '%'
239 prefix. For example, %12, %2, %44.</li>
240
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame^]241 <li>Constants, which are described in a <a href="#constants">section about
242 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]243</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]244
245<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
246don't need to worry about name clashes with reserved words, and the set of
247reserved words may be expanded in the future without penalty. Additionally,
248unnamed identifiers allow a compiler to quickly come up with a temporary
249variable without having to avoid symbol table conflicts.</p>
250
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]251<p>Reserved words in LLVM are very similar to reserved words in other
252languages. There are keywords for different opcodes ('<tt><a
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]253href="#i_add">add</a></tt>', '<tt><a href="#i_cast">cast</a></tt>', '<tt><a
254href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
255href="#t_void">void</a></tt>', '<tt><a href="#t_uint">uint</a></tt>', etc...),
256and others. These reserved words cannot conflict with variable names, because
257none of them start with a '%' character.</p>
258
259<p>Here is an example of LLVM code to multiply the integer variable
260'<tt>%X</tt>' by 8:</p>
261
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]262<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]263
264<pre>
265 %result = <a href="#i_mul">mul</a> uint %X, 8
266</pre>
267
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]268<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]269
270<pre>
271 %result = <a href="#i_shl">shl</a> uint %X, ubyte 3
272</pre>
273
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]274<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]275
276<pre>
277 <a href="#i_add">add</a> uint %X, %X <i>; yields {uint}:%0</i>
278 <a href="#i_add">add</a> uint %0, %0 <i>; yields {uint}:%1</i>
279 %result = <a href="#i_add">add</a> uint %1, %1
280</pre>
281
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]282<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
283important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]284
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]285<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]286
287 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
288 line.</li>
289
290 <li>Unnamed temporaries are created when the result of a computation is not
291 assigned to a named value.</li>
292
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]293 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]294
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]295</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]296
297<p>...and it also show a convention that we follow in this document. When
298demonstrating instructions, we will follow an instruction with a comment that
299defines the type and name of value produced. Comments are shown in italic
300text.</p>
301
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]302</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]303
304<!-- *********************************************************************** -->
305<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
306<!-- *********************************************************************** -->
307
308<!-- ======================================================================= -->
309<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
310</div>
311
312<div class="doc_text">
313
314<p>LLVM programs are composed of "Module"s, each of which is a
315translation unit of the input programs. Each module consists of
316functions, global variables, and symbol table entries. Modules may be
317combined together with the LLVM linker, which merges function (and
318global variable) definitions, resolves forward declarations, and merges
319symbol table entries. Here is an example of the "hello world" module:</p>
320
321<pre><i>; Declare the string constant as a global constant...</i>
322<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
323 href="#globalvars">constant</a> <a href="#t_array">[13 x sbyte]</a> c"hello world\0A\00" <i>; [13 x sbyte]*</i>
324
325<i>; External declaration of the puts function</i>
326<a href="#functionstructure">declare</a> int %puts(sbyte*) <i>; int(sbyte*)* </i>
327
328<i>; Definition of main function</i>
329int %main() { <i>; int()* </i>
330 <i>; Convert [13x sbyte]* to sbyte *...</i>
331 %cast210 = <a
332 href="#i_getelementptr">getelementptr</a> [13 x sbyte]* %.LC0, long 0, long 0 <i>; sbyte*</i>
333
334 <i>; Call puts function to write out the string to stdout...</i>
335 <a
336 href="#i_call">call</a> int %puts(sbyte* %cast210) <i>; int</i>
337 <a
338 href="#i_ret">ret</a> int 0<br>}<br></pre>
339
340<p>This example is made up of a <a href="#globalvars">global variable</a>
341named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
342function, and a <a href="#functionstructure">function definition</a>
343for "<tt>main</tt>".</p>
344
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]345<p>In general, a module is made up of a list of global values,
346where both functions and global variables are global values. Global values are
347represented by a pointer to a memory location (in this case, a pointer to an
348array of char, and a pointer to a function), and have one of the following <a
349href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]350
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]351</div>
352
353<!-- ======================================================================= -->
354<div class="doc_subsection">
355 <a name="linkage">Linkage Types</a>
356</div>
357
358<div class="doc_text">
359
360<p>
361All Global Variables and Functions have one of the following types of linkage:
362</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]363
364<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]365
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]366 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]367
368 <dd>Global values with internal linkage are only directly accessible by
369 objects in the current module. In particular, linking code into a module with
370 an internal global value may cause the internal to be renamed as necessary to
371 avoid collisions. Because the symbol is internal to the module, all
372 references can be updated. This corresponds to the notion of the
373 '<tt>static</tt>' keyword in C, or the idea of "anonymous namespaces" in C++.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]374 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]375
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]376 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]377
378 <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with
379 the twist that linking together two modules defining the same
380 <tt>linkonce</tt> globals will cause one of the globals to be discarded. This
381 is typically used to implement inline functions. Unreferenced
382 <tt>linkonce</tt> globals are allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]383 </dd>
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_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]386
387 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
388 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
389 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]390 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]391
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]392 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]393
394 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
395 pointer to array type. When two global variables with appending linkage are
396 linked together, the two global arrays are appended together. This is the
397 LLVM, typesafe, equivalent of having the system linker append together
398 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]399 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]400
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]401 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]402
403 <dd>If none of the above identifiers are used, the global is externally
404 visible, meaning that it participates in linkage and can be used to resolve
405 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]406 </dd>
407</dl>
408
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]409<p><a name="linkage_external">For example, since the "<tt>.LC0</tt>"
410variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
411variable and was linked with this one, one of the two would be renamed,
412preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
413external (i.e., lacking any linkage declarations), they are accessible
414outside of the current module. It is illegal for a function <i>declaration</i>
415to have any linkage type other than "externally visible".</a></p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]416
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]417</div>
418
419<!-- ======================================================================= -->
420<div class="doc_subsection">
421 <a name="globalvars">Global Variables</a>
422</div>
423
424<div class="doc_text">
425
426<p>Global variables define regions of memory allocated at compilation
427time instead of run-time. Global variables may optionally be
428initialized. A variable may be defined as a global "constant", which
429indicates that the contents of the variable will never be modified
430(enabling better optimization, allowing the global data to be placed in the
431read-only section of an executable, etc).</p>
432
433<p>As SSA values, global variables define pointer values that are in
434scope (i.e. they dominate) all basic blocks in the program. Global
435variables always define a pointer to their "content" type because they
436describe a region of memory, and all memory objects in LLVM are
437accessed through pointers.</p>
438
439</div>
440
441
442<!-- ======================================================================= -->
443<div class="doc_subsection">
444 <a name="functionstructure">Functions</a>
445</div>
446
447<div class="doc_text">
448
449<p>LLVM function definitions are composed of a (possibly empty) argument list,
450an opening curly brace, a list of basic blocks, and a closing curly brace. LLVM
451function declarations are defined with the "<tt>declare</tt>" keyword, a
452function name, and a function signature.</p>
453
454<p>A function definition contains a list of basic blocks, forming the CFG for
455the function. Each basic block may optionally start with a label (giving the
456basic block a symbol table entry), contains a list of instructions, and ends
457with a <a href="#terminators">terminator</a> instruction (such as a branch or
458function return).</p>
459
460<p>The first basic block in program is special in two ways: it is immediately
461executed on entrance to the function, and it is not allowed to have predecessor
462basic blocks (i.e. there can not be any branches to the entry block of a
463function). Because the block can have no predecessors, it also cannot have any
464<a href="#i_phi">PHI nodes</a>.</p>
465
466<p>LLVM functions are identified by their name and type signature. Hence, two
467functions with the same name but different parameter lists or return values are
468considered different functions, and LLVM will resolves references to each
469appropriately.</p>
470
471</div>
472
473
474
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]475<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]476<div class="doc_section"> <a name="typesystem">Type System</a> </div>
477<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]478
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]479<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]480
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]481<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]482intermediate representation. Being typed enables a number of
483optimizations to be performed on the IR directly, without having to do
484extra analyses on the side before the transformation. A strong type
485system makes it easier to read the generated code and enables novel
486analyses and transformations that are not feasible to perform on normal
487three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]488
489</div>
490
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]491<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]492<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]493<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]494<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]495system. The current set of primitive types are as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]496
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]497<table class="layout">
498 <tr class="layout">
499 <td class="left">
500 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]501 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]502 <tr><th>Type</th><th>Description</th></tr>
503 <tr><td><tt>void</tt></td><td>No value</td></tr>
504 <tr><td><tt>ubyte</tt></td><td>Unsigned 8 bit value</td></tr>
505 <tr><td><tt>ushort</tt></td><td>Unsigned 16 bit value</td></tr>
506 <tr><td><tt>uint</tt></td><td>Unsigned 32 bit value</td></tr>
507 <tr><td><tt>ulong</tt></td><td>Unsigned 64 bit value</td></tr>
508 <tr><td><tt>float</tt></td><td>32 bit floating point value</td></tr>
509 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]510 </tbody>
511 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]512 </td>
513 <td class="right">
514 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]515 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]516 <tr><th>Type</th><th>Description</th></tr>
517 <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
518 <tr><td><tt>sbyte</tt></td><td>Signed 8 bit value</td></tr>
519 <tr><td><tt>short</tt></td><td>Signed 16 bit value</td></tr>
520 <tr><td><tt>int</tt></td><td>Signed 32 bit value</td></tr>
521 <tr><td><tt>long</tt></td><td>Signed 64 bit value</td></tr>
522 <tr><td><tt>double</tt></td><td>64 bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]523 </tbody>
524 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]525 </td>
526 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]527</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]528</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]529
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]530<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]531<div class="doc_subsubsection"> <a name="t_classifications">Type
532Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]533<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]534<p>These different primitive types fall into a few useful
535classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]536
537<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]538 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]539 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]540 <tr>
541 <td><a name="t_signed">signed</a></td>
542 <td><tt>sbyte, short, int, long, float, double</tt></td>
543 </tr>
544 <tr>
545 <td><a name="t_unsigned">unsigned</a></td>
546 <td><tt>ubyte, ushort, uint, ulong</tt></td>
547 </tr>
548 <tr>
549 <td><a name="t_integer">integer</a></td>
550 <td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td>
551 </tr>
552 <tr>
553 <td><a name="t_integral">integral</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]554 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long</tt>
555 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]556 </tr>
557 <tr>
558 <td><a name="t_floating">floating point</a></td>
559 <td><tt>float, double</tt></td>
560 </tr>
561 <tr>
562 <td><a name="t_firstclass">first class</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]563 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long,<br>
564 float, double, <a href="#t_pointer">pointer</a>,
565 <a href="#t_packed">packed</a></tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]566 </tr>
567 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]568</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]569
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]570<p>The <a href="#t_firstclass">first class</a> types are perhaps the
571most important. Values of these types are the only ones which can be
572produced by instructions, passed as arguments, or used as operands to
573instructions. This means that all structures and arrays must be
574manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]575</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]576
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]577<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]578<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]579
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]580<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]581
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]582<p>The real power in LLVM comes from the derived types in the system.
583This is what allows a programmer to represent arrays, functions,
584pointers, and other useful types. Note that these derived types may be
585recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]586
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]587</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]588
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]589<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]590<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]591
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]592<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]593
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]594<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]595
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]596<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]597sequentially in memory. The array type requires a size (number of
598elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]599
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]600<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]601
602<pre>
603 [&lt;# elements&gt; x &lt;elementtype&gt;]
604</pre>
605
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]606<p>The number of elements is a constant integer value, elementtype may
607be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]608
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]609<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]610<table class="layout">
611 <tr class="layout">
612 <td class="left">
613 <tt>[40 x int ]</tt><br/>
614 <tt>[41 x int ]</tt><br/>
615 <tt>[40 x uint]</tt><br/>
616 </td>
617 <td class="left">
618 Array of 40 integer values.<br/>
619 Array of 41 integer values.<br/>
620 Array of 40 unsigned integer values.<br/>
621 </td>
622 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]623</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]624<p>Here are some examples of multidimensional arrays:</p>
625<table class="layout">
626 <tr class="layout">
627 <td class="left">
628 <tt>[3 x [4 x int]]</tt><br/>
629 <tt>[12 x [10 x float]]</tt><br/>
630 <tt>[2 x [3 x [4 x uint]]]</tt><br/>
631 </td>
632 <td class="left">
633 3x4 array integer values.<br/>
634 12x10 array of single precision floating point values.<br/>
635 2x3x4 array of unsigned integer values.<br/>
636 </td>
637 </tr>
638</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]639</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]640
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]641<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]642<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]643<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]644<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]645<p>The function type can be thought of as a function signature. It
646consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]647Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]648(which are structures of pointers to functions), for indirect function
649calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]650<p>
651The return type of a function type cannot be an aggregate type.
652</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]653<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]654<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]655<p>Where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
656specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]657which indicates that the function takes a variable number of arguments.
658Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]659 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]660<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]661<table class="layout">
662 <tr class="layout">
663 <td class="left">
664 <tt>int (int)</tt> <br/>
665 <tt>float (int, int *) *</tt><br/>
666 <tt>int (sbyte *, ...)</tt><br/>
667 </td>
668 <td class="left">
669 function taking an <tt>int</tt>, returning an <tt>int</tt><br/>
670 <a href="#t_pointer">Pointer</a> to a function that takes an
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]671 <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]672 returning <tt>float</tt>.<br/>
673 A vararg function that takes at least one <a href="#t_pointer">pointer</a>
674 to <tt>sbyte</tt> (signed char in C), which returns an integer. This is
675 the signature for <tt>printf</tt> in LLVM.<br/>
676 </td>
677 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]678</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]679
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]680</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]681<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]682<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]683<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]684<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]685<p>The structure type is used to represent a collection of data members
686together in memory. The packing of the field types is defined to match
687the ABI of the underlying processor. The elements of a structure may
688be any type that has a size.</p>
689<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
690and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
691field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
692instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]693<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]694<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]695<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]696<table class="layout">
697 <tr class="layout">
698 <td class="left">
699 <tt>{ int, int, int }</tt><br/>
700 <tt>{ float, int (int) * }</tt><br/>
701 </td>
702 <td class="left">
703 a triple of three <tt>int</tt> values<br/>
704 A pair, where the first element is a <tt>float</tt> and the second element
705 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
706 that takes an <tt>int</tt>, returning an <tt>int</tt>.<br/>
707 </td>
708 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]709</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]710</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]711
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]712<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]713<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]714<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]715<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]716<p>As in many languages, the pointer type represents a pointer or
717reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]718<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]719<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]720<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]721<table class="layout">
722 <tr class="layout">
723 <td class="left">
724 <tt>[4x int]*</tt><br/>
725 <tt>int (int *) *</tt><br/>
726 </td>
727 <td class="left">
728 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
729 four <tt>int</tt> values<br/>
730 A <a href="#t_pointer">pointer</a> to a <a
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]731 href="#t_function">function</a> that takes an <tt>int</tt>, returning an
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]732 <tt>int</tt>.<br/>
733 </td>
734 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]735</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]736</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]737
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]738<!-- _______________________________________________________________________ -->
739<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]740<div class="doc_text">
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]741<h5>Overview:</h5>
742<p>A packed type is a simple derived type that represents a vector
743of elements. Packed types are used when multiple primitive data
744are operated in parallel using a single instruction (SIMD).
745A packed type requires a size (number of
746elements) and an underlying primitive data type. Packed types are
747considered <a href="#t_firstclass">first class</a>.</p>
748<h5>Syntax:</h5>
749<pre> &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;<br></pre>
750<p>The number of elements is a constant integer value, elementtype may
751be any integral or floating point type.</p>
752<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]753<table class="layout">
754 <tr class="layout">
755 <td class="left">
756 <tt>&lt;4 x int&gt;</tt><br/>
757 <tt>&lt;8 x float&gt;</tt><br/>
758 <tt>&lt;2 x uint&gt;</tt><br/>
759 </td>
760 <td class="left">
761 Packed vector of 4 integer values.<br/>
762 Packed vector of 8 floating-point values.<br/>
763 Packed vector of 2 unsigned integer values.<br/>
764 </td>
765 </tr>
766</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]767</div>
768
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]769<!-- *********************************************************************** -->
770<div class="doc_section"> <a name="constants">Constants</a> </div>
771<!-- *********************************************************************** -->
772
773<div class="doc_text">
774
775<p>LLVM has several different basic types of constants. This section describes
776them all and their syntax.</p>
777
778</div>
779
780<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame^]781<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]782
783<div class="doc_text">
784
785<dl>
786 <dt><b>Boolean constants</b></dt>
787
788 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
789 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
790 </dd>
791
792 <dt><b>Integer constants</b></dt>
793
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame^]794 <dd>Standard integers (such as '4') are constants of the <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]795 href="#t_integer">integer</a> type. Negative numbers may be used with signed
796 integer types.
797 </dd>
798
799 <dt><b>Floating point constants</b></dt>
800
801 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
802 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame^]803 notation. Floating point constants have an optional hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]804 notation (see below). Floating point constants must have a <a
805 href="#t_floating">floating point</a> type. </dd>
806
807 <dt><b>Null pointer constants</b></dt>
808
809 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant,
810 and must be of <a href="#t_pointer">pointer type</a>.</dd>
811
812</dl>
813
814<p>The one non-intuitive notation for constants is the optional hexidecimal form
815of floating point constants. For example, the form '<tt>double
8160x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
8174.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame^]818(and the only time that they are generated by the disassembler) is when a
819floating point constant must be emitted but it cannot be represented as a
820decimal floating point number. For example, NaN's, infinities, and other
821special values are represented in their IEEE hexadecimal format so that
822assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]823
824</div>
825
826<!-- ======================================================================= -->
827<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
828</div>
829
830<div class="doc_text">
831
832<dl>
833 <dt><b>Structure constants</b></dt>
834
835 <dd>Structure constants are represented with notation similar to structure
836 type definitions (a comma separated list of elements, surrounded by braces
837 (<tt>{}</tt>). For example: "<tt>{ int 4, float 17.0 }</tt>". Structure
838 constants must have <a href="#t_struct">structure type</a>, and the number and
839 types of elements must match those specified by the type.
840 </dd>
841
842 <dt><b>Array constants</b></dt>
843
844 <dd>Array constants are represented with notation similar to array type
845 definitions (a comma separated list of elements, surrounded by square brackets
846 (<tt>[]</tt>). For example: "<tt>[ int 42, int 11, int 74 ]</tt>". Array
847 constants must have <a href="#t_array">array type</a>, and the number and
848 types of elements must match those specified by the type.
849 </dd>
850
851 <dt><b>Packed constants</b></dt>
852
853 <dd>Packed constants are represented with notation similar to packed type
854 definitions (a comma separated list of elements, surrounded by
855 less-than/greater-than's (<tt>&lt;&gt;</tt>). For example: "<tt>&lt; int 42,
856 int 11, int 74, int 100 &gt;</tt>". Packed constants must have <a
857 href="#t_packed">packed type</a>, and the number and types of elements must
858 match those specified by the type.
859 </dd>
860
861 <dt><b>Zero initialization</b></dt>
862
863 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
864 value to zero of <em>any</em> type, including scalar and aggregate types.
865 This is often used to avoid having to print large zero initializers (e.g. for
866 large arrays), and is always exactly equivalent to using explicit zero
867 initializers.
868 </dd>
869</dl>
870
871</div>
872
873<!-- ======================================================================= -->
874<div class="doc_subsection">
875 <a name="globalconstants">Global Variable and Function Addresses</a>
876</div>
877
878<div class="doc_text">
879
880<p>The addresses of <a href="#globalvars">global variables</a> and <a
881href="#functionstructure">functions</a> are always implicitly valid (link-time)
882constants. These constants explicitly referenced when the <a
883href="#identifiers">identifier for the global</a> is used, and always have <a
884href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
885file:</p>
886
887<pre>
888 %X = global int 17
889 %Y = global int 42
890 %Z = global [2 x int*] [ int* %X, int* %Y ]
891</pre>
892
893</div>
894
895<!-- ======================================================================= -->
896<div class="doc_subsection"><a name="undefvalues">Undefined Values</a>
897</div>
898
899<div class="doc_text">
900
901<p>The string '<tt>undef</tt>' is recognized as a filler that has no specified
902value. Undefined values may be of any type, and be used anywhere a constant
903is.</p>
904
905<p>Undefined values are used to indicate the compiler that the program is well
906defined no matter what value is used, giving it more freedom.</p>
907
908</div>
909
910<!-- ======================================================================= -->
911<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
912</div>
913
914<div class="doc_text">
915
916<p>Constant expressions are used to allow expressions involving other constants
917to be used as constants. Constant expressions may be of any <a
918href="#t_firstclass">first class</a> type, and may involve any LLVM operation
919that does not have side effects (e.g. load and call are not supported). The
920following is the syntax for constant expressions:</p>
921
922<dl>
923 <dt><b><tt>cast ( CST to TYPE )</tt></b></dt>
924
925 <dd>Cast a constant to another type.</dd>
926
927 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
928
929 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
930 constants. As with the <a href="#i_getelementptr">getelementptr</a>
931 instruction, the index list may have zero or more indexes, which are required
932 to make sense for the type of "CSTPTR".</dd>
933
934 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
935
936 <dd>Perform the specied operation of the LHS and RHS constants. OPCODE may be
937 any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
938 binary</a> operations. The constraints on operands are the same as those for
939 the corresponding instruction (e.g. no bitwise operations on floating point
940 are allowed).</dd>
941
942</dl>
943
944</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]945
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]946<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]947<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
948<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]949
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]950<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]951
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]952<p>The LLVM instruction set consists of several different
953classifications of instructions: <a href="#terminators">terminator
954instructions</a>, <a href="#binaryops">binary instructions</a>, <a
955 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
956instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]957
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]958</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]959
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]960<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]961<div class="doc_subsection"> <a name="terminators">Terminator
962Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]963
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]964<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]965
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]966<p>As mentioned <a href="#functionstructure">previously</a>, every
967basic block in a program ends with a "Terminator" instruction, which
968indicates which block should be executed after the current block is
969finished. These terminator instructions typically yield a '<tt>void</tt>'
970value: they produce control flow, not values (the one exception being
971the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]972
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]973<p>There are five different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]974 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
975instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]976the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
977 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
978 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]979
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]980</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]981
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]982<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]983<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
984Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]985<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]986<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]987<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]988 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]989</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]990<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]991<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
992value) from a function, back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]993<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]994returns a value and then causes control flow, and one that just causes
995control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]996<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]997<p>The '<tt>ret</tt>' instruction may return any '<a
998 href="#t_firstclass">first class</a>' type. Notice that a function is
999not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1000instruction inside of the function that returns a value that does not
1001match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1002<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1003<p>When the '<tt>ret</tt>' instruction is executed, control flow
1004returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1005 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1006the instruction after the call. If the caller was an "<a
1007 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
1008at the beginning "normal" of the destination block. If the instruction
1009returns a value, that value shall set the call or invoke instruction's
1010return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1011<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1012<pre> ret int 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1013 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1014</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1015</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1016<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1017<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1018<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1019<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1020<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]1021</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1022<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1023<p>The '<tt>br</tt>' instruction is used to cause control flow to
1024transfer to a different basic block in the current function. There are
1025two forms of this instruction, corresponding to a conditional branch
1026and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1027<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1028<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1029single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1030unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1031value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1032<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1033<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1034argument is evaluated. If the value is <tt>true</tt>, control flows
1035to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1036control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1037<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1038<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
1039 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]1040</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1041<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1042<div class="doc_subsubsection">
1043 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1044</div>
1045
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1046<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1047<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1048
1049<pre>
1050 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1051</pre>
1052
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1053<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1054
1055<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1056several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1057instruction, allowing a branch to occur to one of many possible
1058destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1059
1060
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1061<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1062
1063<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1064comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1065an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1066table is not allowed to contain duplicate constant entries.</p>
1067
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1068<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1069
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1070<p>The <tt>switch</tt> instruction specifies a table of values and
1071destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1072table is searched for the given value. If the value is found, control flow is
1073transfered to the corresponding destination; otherwise, control flow is
1074transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1075
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1076<h5>Implementation:</h5>
1077
1078<p>Depending on properties of the target machine and the particular
1079<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1080ways. For example, it could be generated as a series of chained conditional
1081branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1082
1083<h5>Example:</h5>
1084
1085<pre>
1086 <i>; Emulate a conditional br instruction</i>
1087 %Val = <a href="#i_cast">cast</a> bool %value to int
1088 switch int %Val, label %truedest [int 0, label %falsedest ]
1089
1090 <i>; Emulate an unconditional br instruction</i>
1091 switch uint 0, label %dest [ ]
1092
1093 <i>; Implement a jump table:</i>
1094 switch uint %val, label %otherwise [ uint 0, label %onzero
1095 uint 1, label %onone
1096 uint 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1097</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1098</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1099<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1100<div class="doc_subsubsection"> <a name="i_invoke">'<tt>invoke</tt>'
1101Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1102<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1103<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1104<pre> &lt;result&gt; = invoke &lt;ptr to function ty&gt; %&lt;function ptr val&gt;(&lt;function args&gt;)<br> to label &lt;normal label&gt; except label &lt;exception label&gt;<br></pre>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1105<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1106<p>The '<tt>invoke</tt>' instruction causes control to transfer to a
1107specified function, with the possibility of control flow transfer to
1108either the '<tt>normal</tt>' <tt>label</tt> label or the '<tt>exception</tt>'<tt>label</tt>.
1109If the callee function returns with the "<tt><a href="#i_ret">ret</a></tt>"
1110instruction, control flow will return to the "normal" label. If the
1111callee (or any indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
1112instruction, control is interrupted, and continued at the dynamically
1113nearest "except" label.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1114<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1115<p>This instruction requires several arguments:</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1116<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1117 <li>'<tt>ptr to function ty</tt>': shall be the signature of the
1118pointer to function value being invoked. In most cases, this is a
1119direct function invocation, but indirect <tt>invoke</tt>s are just as
1120possible, branching off an arbitrary pointer to function value. </li>
1121 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer
1122to a function to be invoked. </li>
1123 <li>'<tt>function args</tt>': argument list whose types match the
1124function signature argument types. If the function signature indicates
1125the function accepts a variable number of arguments, the extra
1126arguments can be specified. </li>
1127 <li>'<tt>normal label</tt>': the label reached when the called
1128function executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1129 <li>'<tt>exception label</tt>': the label reached when a callee
1130returns with the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1131</ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1132<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1133<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1134 href="#i_call">call</a></tt>' instruction in most regards. The
1135primary difference is that it establishes an association with a label,
1136which is used by the runtime library to unwind the stack.</p>
1137<p>This instruction is used in languages with destructors to ensure
1138that proper cleanup is performed in the case of either a <tt>longjmp</tt>
1139or a thrown exception. Additionally, this is important for
1140implementation of '<tt>catch</tt>' clauses in high-level languages that
1141support them.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1142<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1143<pre> %retval = invoke int %Test(int 15)<br> to label %Continue<br> except label %TestCleanup <i>; {int}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1144</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1145</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1146
1147
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1148<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1149
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1150<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1151Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1152
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1153<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1154
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1155<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1156<pre>
1157 unwind
1158</pre>
1159
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1160<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1161
1162<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1163at the first callee in the dynamic call stack which used an <a
1164href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1165primarily used to implement exception handling.</p>
1166
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1167<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1168
1169<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1170immediately halt. The dynamic call stack is then searched for the first <a
1171href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1172execution continues at the "exceptional" destination block specified by the
1173<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1174dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1175</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1176
1177<!-- _______________________________________________________________________ -->
1178
1179<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1180Instruction</a> </div>
1181
1182<div class="doc_text">
1183
1184<h5>Syntax:</h5>
1185<pre>
1186 unreachable
1187</pre>
1188
1189<h5>Overview:</h5>
1190
1191<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1192instruction is used to inform the optimizer that a particular portion of the
1193code is not reachable. This can be used to indicate that the code after a
1194no-return function cannot be reached, and other facts.</p>
1195
1196<h5>Semantics:</h5>
1197
1198<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1199</div>
1200
1201
1202
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1203<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1204<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1205<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1206<p>Binary operators are used to do most of the computation in a
1207program. They require two operands, execute an operation on them, and
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1208produce a single value. Although, that single value might represent
1209multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1210The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1211necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1212<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1213</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1214<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1215<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1216Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1217<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1218<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1219<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]1220</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1221<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1222<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1223<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1224<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1225 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1226 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1227Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1228<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1229<p>The value produced is the integer or floating point sum of the two
1230operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1231<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1232<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]1233</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1234</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1235<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1236<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1237Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1238<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1239<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1240<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]1241</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1242<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1243<p>The '<tt>sub</tt>' instruction returns the difference of its two
1244operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1245<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1246instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1247<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1248<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1249 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1250values.
1251This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1252Both arguments must have identical types.</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>The value produced is the integer or floating point difference of
1255the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1256<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1257<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]1258 &lt;result&gt; = sub int 0, %val <i>; yields {int}:result = -%var</i>
1259</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1260</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1261<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1262<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1263Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1264<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1265<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1266<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]1267</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1268<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1269<p>The '<tt>mul</tt>' instruction returns the product of its two
1270operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1271<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1272<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1273 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1274values.
1275This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1276Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1277<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1278<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1279two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1280<p>There is no signed vs unsigned multiplication. The appropriate
1281action is taken based on the type of the operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1282<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1283<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]1284</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1285</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1286<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1287<div class="doc_subsubsection"> <a name="i_div">'<tt>div</tt>'
1288Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1289<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1290<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1291<pre> &lt;result&gt; = div &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1292</pre>
1293<h5>Overview:</h5>
1294<p>The '<tt>div</tt>' instruction returns the quotient of its two
1295operands.</p>
1296<h5>Arguments:</h5>
1297<p>The two arguments to the '<tt>div</tt>' instruction must be either <a
1298 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1299values.
1300This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1301Both arguments must have identical types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1302<h5>Semantics:</h5>
1303<p>The value produced is the integer or floating point quotient of the
1304two operands.</p>
1305<h5>Example:</h5>
1306<pre> &lt;result&gt; = div int 4, %var <i>; yields {int}:result = 4 / %var</i>
1307</pre>
1308</div>
1309<!-- _______________________________________________________________________ -->
1310<div class="doc_subsubsection"> <a name="i_rem">'<tt>rem</tt>'
1311Instruction</a> </div>
1312<div class="doc_text">
1313<h5>Syntax:</h5>
1314<pre> &lt;result&gt; = rem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1315</pre>
1316<h5>Overview:</h5>
1317<p>The '<tt>rem</tt>' instruction returns the remainder from the
1318division of its two operands.</p>
1319<h5>Arguments:</h5>
1320<p>The two arguments to the '<tt>rem</tt>' instruction must be either <a
1321 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1322values.
1323This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1324Both arguments must have identical types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1325<h5>Semantics:</h5>
1326<p>This returns the <i>remainder</i> of a division (where the result
1327has the same sign as the divisor), not the <i>modulus</i> (where the
1328result has the same sign as the dividend) of a value. For more
1329information about the difference, see: <a
1330 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1331Math Forum</a>.</p>
1332<h5>Example:</h5>
1333<pre> &lt;result&gt; = rem int 4, %var <i>; yields {int}:result = 4 % %var</i>
1334</pre>
1335</div>
1336<!-- _______________________________________________________________________ -->
1337<div class="doc_subsubsection"> <a name="i_setcc">'<tt>set<i>cc</i></tt>'
1338Instructions</a> </div>
1339<div class="doc_text">
1340<h5>Syntax:</h5>
1341<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]1342 &lt;result&gt; = setne &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1343 &lt;result&gt; = setlt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1344 &lt;result&gt; = setgt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1345 &lt;result&gt; = setle &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1346 &lt;result&gt; = setge &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1347</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1348<h5>Overview:</h5>
1349<p>The '<tt>set<i>cc</i></tt>' family of instructions returns a boolean
1350value based on a comparison of their two operands.</p>
1351<h5>Arguments:</h5>
1352<p>The two arguments to the '<tt>set<i>cc</i></tt>' instructions must
1353be of <a href="#t_firstclass">first class</a> type (it is not possible
1354to compare '<tt>label</tt>'s, '<tt>array</tt>'s, '<tt>structure</tt>'
1355or '<tt>void</tt>' values, etc...). Both arguments must have identical
1356types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1357<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1358<p>The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1359value if both operands are equal.<br>
1360The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1361value if both operands are unequal.<br>
1362The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1363value if the first operand is less than the second operand.<br>
1364The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1365value if the first operand is greater than the second operand.<br>
1366The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1367value if the first operand is less than or equal to the second operand.<br>
1368The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1369value if the first operand is greater than or equal to the second
1370operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1371<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1372<pre> &lt;result&gt; = seteq int 4, 5 <i>; yields {bool}:result = false</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1373 &lt;result&gt; = setne float 4, 5 <i>; yields {bool}:result = true</i>
1374 &lt;result&gt; = setlt uint 4, 5 <i>; yields {bool}:result = true</i>
1375 &lt;result&gt; = setgt sbyte 4, 5 <i>; yields {bool}:result = false</i>
1376 &lt;result&gt; = setle sbyte 4, 5 <i>; yields {bool}:result = true</i>
1377 &lt;result&gt; = setge sbyte 4, 5 <i>; yields {bool}:result = false</i>
1378</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1379</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1380<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1381<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1382Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1383<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1384<p>Bitwise binary operators are used to do various forms of
1385bit-twiddling in a program. They are generally very efficient
1386instructions, and can commonly be strength reduced from other
1387instructions. They require two operands, execute an operation on them,
1388and produce a single value. The resulting value of the bitwise binary
1389operators is always the same type as its first operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1390</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1391<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1392<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1393Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1394<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1395<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1396<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]1397</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1398<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1399<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1400its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1401<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1402<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1403 href="#t_integral">integral</a> values. Both arguments must have
1404identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1405<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1406<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1407<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1408<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1409<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1410 <tbody>
1411 <tr>
1412 <td>In0</td>
1413 <td>In1</td>
1414 <td>Out</td>
1415 </tr>
1416 <tr>
1417 <td>0</td>
1418 <td>0</td>
1419 <td>0</td>
1420 </tr>
1421 <tr>
1422 <td>0</td>
1423 <td>1</td>
1424 <td>0</td>
1425 </tr>
1426 <tr>
1427 <td>1</td>
1428 <td>0</td>
1429 <td>0</td>
1430 </tr>
1431 <tr>
1432 <td>1</td>
1433 <td>1</td>
1434 <td>1</td>
1435 </tr>
1436 </tbody>
1437</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1438</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1439<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1440<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]1441 &lt;result&gt; = and int 15, 40 <i>; yields {int}:result = 8</i>
1442 &lt;result&gt; = and int 4, 8 <i>; yields {int}:result = 0</i>
1443</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1444</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1445<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1446<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1447<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1448<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1449<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]1450</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1451<h5>Overview:</h5>
1452<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1453or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1454<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1455<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1456 href="#t_integral">integral</a> values. Both arguments must have
1457identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1458<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1459<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1460<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1461<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1462<table border="1" cellspacing="0" cellpadding="4">
1463 <tbody>
1464 <tr>
1465 <td>In0</td>
1466 <td>In1</td>
1467 <td>Out</td>
1468 </tr>
1469 <tr>
1470 <td>0</td>
1471 <td>0</td>
1472 <td>0</td>
1473 </tr>
1474 <tr>
1475 <td>0</td>
1476 <td>1</td>
1477 <td>1</td>
1478 </tr>
1479 <tr>
1480 <td>1</td>
1481 <td>0</td>
1482 <td>1</td>
1483 </tr>
1484 <tr>
1485 <td>1</td>
1486 <td>1</td>
1487 <td>1</td>
1488 </tr>
1489 </tbody>
1490</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1491</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1492<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1493<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]1494 &lt;result&gt; = or int 15, 40 <i>; yields {int}:result = 47</i>
1495 &lt;result&gt; = or int 4, 8 <i>; yields {int}:result = 12</i>
1496</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1497</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1498<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1499<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
1500Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1501<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1502<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1503<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]1504</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1505<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1506<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
1507or of its two operands. The <tt>xor</tt> is used to implement the
1508"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1509<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1510<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1511 href="#t_integral">integral</a> values. Both arguments must have
1512identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1513<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1514<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1515<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1516<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1517<table border="1" cellspacing="0" cellpadding="4">
1518 <tbody>
1519 <tr>
1520 <td>In0</td>
1521 <td>In1</td>
1522 <td>Out</td>
1523 </tr>
1524 <tr>
1525 <td>0</td>
1526 <td>0</td>
1527 <td>0</td>
1528 </tr>
1529 <tr>
1530 <td>0</td>
1531 <td>1</td>
1532 <td>1</td>
1533 </tr>
1534 <tr>
1535 <td>1</td>
1536 <td>0</td>
1537 <td>1</td>
1538 </tr>
1539 <tr>
1540 <td>1</td>
1541 <td>1</td>
1542 <td>0</td>
1543 </tr>
1544 </tbody>
1545</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1546</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1547<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1548<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1549<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]1550 &lt;result&gt; = xor int 15, 40 <i>; yields {int}:result = 39</i>
1551 &lt;result&gt; = xor int 4, 8 <i>; yields {int}:result = 12</i>
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1552 &lt;result&gt; = xor int %V, -1 <i>; yields {int}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1553</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1554</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1555<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1556<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
1557Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1558<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1559<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1560<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]1561</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1562<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1563<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
1564the left a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1565<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1566<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1567 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1568type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1569<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1570<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]1571<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1572<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]1573 &lt;result&gt; = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
1574 &lt;result&gt; = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
1575</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1576</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1577<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1578<div class="doc_subsubsection"> <a name="i_shr">'<tt>shr</tt>'
1579Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1580<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1581<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1582<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]1583</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1584<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1585<p>The '<tt>shr</tt>' instruction returns the first operand shifted to
1586the right a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1587<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1588<p>The first argument to the '<tt>shr</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1589 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1590type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1591<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1592<p>If the first argument is a <a href="#t_signed">signed</a> type, the
1593most significant bit is duplicated in the newly free'd bit positions.
1594If the first argument is unsigned, zero bits shall fill the empty
1595positions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1596<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1597<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]1598 &lt;result&gt; = shr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1599 &lt;result&gt; = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
Chris Lattner8c6bb902003-06-18 21:30:51 +0000[diff] [blame]1600 &lt;result&gt; = shr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i>
1601 &lt;result&gt; = shr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1602</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1603</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1604<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1605<div class="doc_subsection"> <a name="memoryops">Memory Access
1606Operations</a></div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1607<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1608<p>A key design point of an SSA-based representation is how it
1609represents memory. In LLVM, no memory locations are in SSA form, which
1610makes things very simple. This section describes how to read, write,
1611allocate and free memory in LLVM.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1612</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1613<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1614<div class="doc_subsubsection"> <a name="i_malloc">'<tt>malloc</tt>'
1615Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1616<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1617<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1618<pre> &lt;result&gt; = malloc &lt;type&gt;, uint &lt;NumElements&gt; <i>; yields {type*}:result</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1619 &lt;result&gt; = malloc &lt;type&gt; <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1620</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1621<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1622<p>The '<tt>malloc</tt>' instruction allocates memory from the system
1623heap and returns a pointer to it.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1624<h5>Arguments:</h5>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]1625<p>The '<tt>malloc</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
1626bytes of memory from the operating system and returns a pointer of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1627appropriate type to the program. The second form of the instruction is
1628a shorter version of the first instruction that defaults to allocating
1629one element.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1630<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1631<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1632<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
1633a pointer is returned.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1634<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1635<pre> %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1636
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1637 %size = <a
1638 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]1639 %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i>
1640 %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1641</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1642</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1643<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1644<div class="doc_subsubsection"> <a name="i_free">'<tt>free</tt>'
1645Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1646<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1647<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1648<pre> free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1649</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1650<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1651<p>The '<tt>free</tt>' instruction returns memory back to the unused
1652memory heap, to be reallocated in the future.</p>
1653<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1654<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1655<p>'<tt>value</tt>' shall be a pointer value that points to a value
1656that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
1657instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1658<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1659<p>Access to the memory pointed to by the pointer is not longer defined
1660after this instruction executes.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1661<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1662<pre> %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1663 free [4 x ubyte]* %array
1664</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1665</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1666<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1667<div class="doc_subsubsection"> <a name="i_alloca">'<tt>alloca</tt>'
1668Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1669<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1670<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1671<pre> &lt;result&gt; = alloca &lt;type&gt;, uint &lt;NumElements&gt; <i>; yields {type*}:result</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1672 &lt;result&gt; = alloca &lt;type&gt; <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1673</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1674<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1675<p>The '<tt>alloca</tt>' instruction allocates memory on the current
1676stack frame of the procedure that is live until the current function
1677returns to its caller.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1678<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1679<p>The the '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
1680bytes of memory on the runtime stack, returning a pointer of the
1681appropriate type to the program. The second form of the instruction is
1682a shorter version of the first that defaults to allocating one element.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1683<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1684<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1685<p>Memory is allocated, a pointer is returned. '<tt>alloca</tt>'d
1686memory is automatically released when the function returns. The '<tt>alloca</tt>'
1687instruction is commonly used to represent automatic variables that must
1688have an address available. When the function returns (either with the <tt><a
1689 href="#i_ret">ret</a></tt> or <tt><a href="#i_invoke">invoke</a></tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1690instructions), the memory is reclaimed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1691<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1692<pre> %ptr = alloca int <i>; yields {int*}:ptr</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1693 %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1694</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1695</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1696<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1697<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
1698Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1699<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1700<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1701<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]1702<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1703<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1704<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1705<p>The argument to the '<tt>load</tt>' instruction specifies the memory
1706address to load from. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]1707 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1708marked as <tt>volatile</tt> then the optimizer is not allowed to modify
1709the number or order of execution of this <tt>load</tt> with other
1710volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
1711instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1712<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1713<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1714<h5>Examples:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1715<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
1716 <a
1717 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1718 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
1719</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1720</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1721<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1722<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
1723Instruction</a> </div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1724<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1725<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]1726 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]1727</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1728<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1729<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1730<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1731<p>There are two arguments to the '<tt>store</tt>' instruction: a value
1732to store and an address to store it into. The type of the '<tt>&lt;pointer&gt;</tt>'
1733operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
1734operand. If the <tt>store</tt> is marked as <tt>volatile</tt> then the
1735optimizer is not allowed to modify the number or order of execution of
1736this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
1737 href="#i_store">store</a></tt> instructions.</p>
1738<h5>Semantics:</h5>
1739<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
1740at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1741<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1742<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
1743 <a
1744 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1745 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
1746</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1747<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1748<div class="doc_subsubsection">
1749 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
1750</div>
1751
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1752<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1753<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1754<pre>
1755 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
1756</pre>
1757
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1758<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1759
1760<p>
1761The '<tt>getelementptr</tt>' instruction is used to get the address of a
1762subelement of an aggregate data structure.</p>
1763
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1764<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1765
1766<p>This instruction takes a list of integer constants that indicate what
1767elements of the aggregate object to index to. The actual types of the arguments
1768provided depend on the type of the first pointer argument. The
1769'<tt>getelementptr</tt>' instruction is used to index down through the type
1770levels of a structure. When indexing into a structure, only <tt>uint</tt>
1771integer constants are allowed. When indexing into an array or pointer
1772<tt>int</tt> and <tt>long</tt> indexes are allowed of any sign.</p>
1773
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1774<p>For example, let's consider a C code fragment and how it gets
1775compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1776
1777<pre>
1778 struct RT {
1779 char A;
1780 int B[10][20];
1781 char C;
1782 };
1783 struct ST {
1784 int X;
1785 double Y;
1786 struct RT Z;
1787 };
1788
1789 int *foo(struct ST *s) {
1790 return &amp;s[1].Z.B[5][13];
1791 }
1792</pre>
1793
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1794<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1795
1796<pre>
1797 %RT = type { sbyte, [10 x [20 x int]], sbyte }
1798 %ST = type { int, double, %RT }
1799
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]1800 implementation
1801
1802 int* %foo(%ST* %s) {
1803 entry:
1804 %reg = getelementptr %ST* %s, int 1, uint 2, uint 1, int 5, int 13
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1805 ret int* %reg
1806 }
1807</pre>
1808
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1809<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1810
1811<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]1812on the pointer type that is being index into. <a href="#t_pointer">Pointer</a>
1813and <a href="#t_array">array</a> types require <tt>uint</tt>, <tt>int</tt>,
1814<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]1815types require <tt>uint</tt> <b>constants</b>.</p>
1816
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1817<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]1818type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT
1819}</tt>' type, a structure. The second index indexes into the third element of
1820the structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]],
1821sbyte }</tt>' type, another structure. The third index indexes into the second
1822element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an
1823array. The two dimensions of the array are subscripted into, yielding an
1824'<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction return a pointer
1825to this element, thus computing a value of '<tt>int*</tt>' type.</p>
1826
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1827<p>Note that it is perfectly legal to index partially through a
1828structure, returning a pointer to an inner element. Because of this,
1829the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1830
1831<pre>
1832 int* "foo"(%ST* %s) {
1833 %t1 = getelementptr %ST* %s, int 1 <i>; yields %ST*:%t1</i>
1834 %t2 = getelementptr %ST* %t1, int 0, uint 2 <i>; yields %RT*:%t2</i>
1835 %t3 = getelementptr %RT* %t2, int 0, uint 1 <i>; yields [10 x [20 x int]]*:%t3</i>
1836 %t4 = getelementptr [10 x [20 x int]]* %t3, int 0, int 5 <i>; yields [20 x int]*:%t4</i>
1837 %t5 = getelementptr [20 x int]* %t4, int 0, int 13 <i>; yields int*:%t5</i>
1838 ret int* %t5
1839 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1840</pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1841<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1842<pre>
1843 <i>; yields [12 x ubyte]*:aptr</i>
1844 %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, uint 1
1845</pre>
1846
1847</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1848<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1849<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1850<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1851<p>The instructions in this category are the "miscellaneous"
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1852instructions, which defy better classification.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1853</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1854<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1855<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
1856Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1857<div class="doc_text">
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1858<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1859<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]1860<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1861<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
1862the SSA graph representing the function.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1863<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1864<p>The type of the incoming values are specified with the first type
1865field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
1866as arguments, with one pair for each predecessor basic block of the
1867current block. Only values of <a href="#t_firstclass">first class</a>
1868type may be used as the value arguments to the PHI node. Only labels
1869may be used as the label arguments.</p>
1870<p>There must be no non-phi instructions between the start of a basic
1871block and the PHI instructions: i.e. PHI instructions must be first in
1872a basic block.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1873<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1874<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
1875value specified by the parameter, depending on which basic block we
1876came from in the last <a href="#terminators">terminator</a> instruction.</p>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1877<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1878<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]1879</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1880
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1881<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1882<div class="doc_subsubsection">
1883 <a name="i_cast">'<tt>cast .. to</tt>' Instruction</a>
1884</div>
1885
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1886<div class="doc_text">
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1887
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1888<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1889
1890<pre>
1891 &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]1892</pre>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1893
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1894<h5>Overview:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1895
1896<p>
1897The '<tt>cast</tt>' instruction is used as the primitive means to convert
1898integers to floating point, change data type sizes, and break type safety (by
1899casting pointers).
1900</p>
1901
1902
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1903<h5>Arguments:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1904
1905<p>
1906The '<tt>cast</tt>' instruction takes a value to cast, which must be a first
1907class value, and a type to cast it to, which must also be a <a
1908href="#t_firstclass">first class</a> type.
1909</p>
1910
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1911<h5>Semantics:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1912
1913<p>
1914This instruction follows the C rules for explicit casts when determining how the
1915data being cast must change to fit in its new container.
1916</p>
1917
1918<p>
1919When casting to bool, any value that would be considered true in the context of
1920a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' values,
1921all else are '<tt>false</tt>'.
1922</p>
1923
1924<p>
1925When extending an integral value from a type of one signness to another (for
1926example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value is sign-extended if the
1927<b>source</b> value is signed, and zero-extended if the source value is
1928unsigned. <tt>bool</tt> values are always zero extended into either zero or
1929one.
1930</p>
1931
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1932<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1933
1934<pre>
1935 %X = cast int 257 to ubyte <i>; yields ubyte:1</i>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame]1936 %Y = cast int 123 to bool <i>; yields bool:true</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1937</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1938</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1939
1940<!-- _______________________________________________________________________ -->
1941<div class="doc_subsubsection">
1942 <a name="i_select">'<tt>select</tt>' Instruction</a>
1943</div>
1944
1945<div class="doc_text">
1946
1947<h5>Syntax:</h5>
1948
1949<pre>
1950 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
1951</pre>
1952
1953<h5>Overview:</h5>
1954
1955<p>
1956The '<tt>select</tt>' instruction is used to choose one value based on a
1957condition, without branching.
1958</p>
1959
1960
1961<h5>Arguments:</h5>
1962
1963<p>
1964The '<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.
1965</p>
1966
1967<h5>Semantics:</h5>
1968
1969<p>
1970If the boolean condition evaluates to true, the instruction returns the first
1971value argument, otherwise it returns the second value argument.
1972</p>
1973
1974<h5>Example:</h5>
1975
1976<pre>
1977 %X = select bool true, ubyte 17, ubyte 42 <i>; yields ubyte:17</i>
1978</pre>
1979</div>
1980
1981
1982
1983
1984
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1985<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1986<div class="doc_subsubsection"> <a name="i_call">'<tt>call</tt>'
1987Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1988<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1989<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1990<pre> &lt;result&gt; = call &lt;ty&gt;* &lt;fnptrval&gt;(&lt;param list&gt;)<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1991<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1992<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1993<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1994<p>This instruction requires several arguments:</p>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1995<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1996 <li>
1997 <p>'<tt>ty</tt>': shall be the signature of the pointer to function
1998value being invoked. The argument types must match the types implied
1999by this signature.</p>
2000 </li>
2001 <li>
2002 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a
2003function to be invoked. In most cases, this is a direct function
2004invocation, but indirect <tt>call</tt>s are just as possible,
2005calling an arbitrary pointer to function values.</p>
2006 </li>
2007 <li>
2008 <p>'<tt>function args</tt>': argument list whose types match the
2009function signature argument types. If the function signature
2010indicates the function accepts a variable number of arguments, the
2011extra arguments can be specified.</p>
2012 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2013</ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2014<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2015<p>The '<tt>call</tt>' instruction is used to cause control flow to
2016transfer to a specified function, with its incoming arguments bound to
2017the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
2018instruction in the called function, control flow continues with the
2019instruction after the function call, and the return value of the
2020function is bound to the result argument. This is a simpler case of
2021the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2022<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2023<pre> %retval = call int %test(int %argc)<br> call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42);<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2024</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2025
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2026<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2027<div class="doc_subsubsection">
2028 <a name="i_vanext">'<tt>vanext</tt>' Instruction</a>
2029</div>
2030
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2031<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2032
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2033<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2034
2035<pre>
2036 &lt;resultarglist&gt; = vanext &lt;va_list&gt; &lt;arglist&gt;, &lt;argty&gt;
2037</pre>
2038
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2039<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2040
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2041<p>The '<tt>vanext</tt>' instruction is used to access arguments passed
2042through the "variable argument" area of a function call. It is used to
2043implement the <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2044
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2045<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2046
2047<p>This instruction takes a <tt>va_list</tt> value and the type of the
2048argument. It returns another <tt>va_list</tt>. The actual type of
2049<tt>va_list</tt> may be defined differently for different targets. Most targets
2050use a <tt>va_list</tt> type of <tt>sbyte*</tt> or some other pointer type.</p>
2051
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2052<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2053
2054<p>The '<tt>vanext</tt>' instruction advances the specified <tt>va_list</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2055past an argument of the specified type. In conjunction with the <a
2056 href="#i_vaarg"><tt>vaarg</tt></a> instruction, it is used to implement
2057the <tt>va_arg</tt> macro available in C. For more information, see
2058the variable argument handling <a href="#int_varargs">Intrinsic
2059Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2060
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2061<p>It is legal for this instruction to be called in a function which
2062does not take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2063function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2064
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2065<p><tt>vanext</tt> is an LLVM instruction instead of an <a
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2066href="#intrinsics">intrinsic function</a> because it takes a type as an
2067argument. The type refers to the current argument in the <tt>va_list</tt>, it
2068tells the compiler how far on the stack it needs to advance to find the next
2069argument</p>
2070
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2071<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2072
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2073<p>See the <a href="#int_varargs">variable argument processing</a>
2074section.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2075
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2076</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2077
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2078<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2079<div class="doc_subsubsection">
2080 <a name="i_vaarg">'<tt>vaarg</tt>' Instruction</a>
2081</div>
2082
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2083<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2084
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2085<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2086
2087<pre>
2088 &lt;resultval&gt; = vaarg &lt;va_list&gt; &lt;arglist&gt;, &lt;argty&gt;
2089</pre>
2090
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2091<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2092
2093<p>The '<tt>vaarg</tt>' instruction is used to access arguments passed through
2094the "variable argument" area of a function call. It is used to implement the
2095<tt>va_arg</tt> macro in C.</p>
2096
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2097<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2098
2099<p>This instruction takes a <tt>va_list</tt> value and the type of the
2100argument. It returns a value of the specified argument type. Again, the actual
2101type of <tt>va_list</tt> is target specific.</p>
2102
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2103<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2104
2105<p>The '<tt>vaarg</tt>' instruction loads an argument of the specified type from
2106the specified <tt>va_list</tt>. In conjunction with the <a
2107href="#i_vanext"><tt>vanext</tt></a> instruction, it is used to implement the
2108<tt>va_arg</tt> macro available in C. For more information, see the variable
2109argument handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
2110
2111<p>It is legal for this instruction to be called in a function which does not
2112take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2113function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2114
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2115<p><tt>vaarg</tt> is an LLVM instruction instead of an <a
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2116href="#intrinsics">intrinsic function</a> because it takes an type as an
2117argument.</p>
2118
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2119<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2120
2121<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
2122
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2123</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2124
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2125<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2126<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
2127<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2128
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2129<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2130
2131<p>LLVM supports the notion of an "intrinsic function". These functions have
2132well known names and semantics, and are required to follow certain
2133restrictions. Overall, these instructions represent an extension mechanism for
2134the LLVM language that does not require changing all of the transformations in
2135LLVM to add to the language (or the bytecode reader/writer, the parser,
2136etc...).</p>
2137
2138<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix, this
2139prefix is reserved in LLVM for intrinsic names, thus functions may not be named
2140this. Intrinsic functions must always be external functions: you cannot define
2141the body of intrinsic functions. Intrinsic functions may only be used in call
2142or invoke instructions: it is illegal to take the address of an intrinsic
2143function. Additionally, because intrinsic functions are part of the LLVM
2144language, it is required that they all be documented here if any are added.</p>
2145
2146
2147<p>
2148Adding an intrinsic to LLVM is straight-forward if it is possible to express the
2149concept in LLVM directly (ie, code generator support is not _required_). To do
2150this, extend the default implementation of the IntrinsicLowering class to handle
2151the intrinsic. Code generators use this class to lower intrinsics they do not
2152understand to raw LLVM instructions that they do.
2153</p>
2154
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2155</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2156
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2157<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2158<div class="doc_subsection">
2159 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
2160</div>
2161
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2162<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2163
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2164<p>Variable argument support is defined in LLVM with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2165 href="#i_vanext"><tt>vanext</tt></a> instruction and these three
2166intrinsic functions. These functions are related to the similarly
2167named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2168
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2169<p>All of these functions operate on arguments that use a
2170target-specific value type "<tt>va_list</tt>". The LLVM assembly
2171language reference manual does not define what this type is, so all
2172transformations should be prepared to handle intrinsics with any type
2173used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2174
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2175<p>This example shows how the <a href="#i_vanext"><tt>vanext</tt></a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2176instruction and the variable argument handling intrinsic functions are
2177used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2178
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2179<pre>
2180int %test(int %X, ...) {
2181 ; Initialize variable argument processing
2182 %ap = call sbyte* %<a href="#i_va_start">llvm.va_start</a>()
2183
2184 ; Read a single integer argument
2185 %tmp = vaarg sbyte* %ap, int
2186
2187 ; Advance to the next argument
2188 %ap2 = vanext sbyte* %ap, int
2189
2190 ; Demonstrate usage of llvm.va_copy and llvm.va_end
2191 %aq = call sbyte* %<a href="#i_va_copy">llvm.va_copy</a>(sbyte* %ap2)
2192 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %aq)
2193
2194 ; Stop processing of arguments.
2195 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %ap2)
2196 ret int %tmp
2197}
2198</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2199</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2200
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2201<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2202<div class="doc_subsubsection">
2203 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
2204</div>
2205
2206
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2207<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2208<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2209<pre> call &lt;va_list&gt; ()* %llvm.va_start()<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2210<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2211<p>The '<tt>llvm.va_start</tt>' intrinsic returns a new <tt>&lt;arglist&gt;</tt>
2212for subsequent use by the variable argument intrinsics.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2213<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2214<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2215macro available in C. In a target-dependent way, it initializes and
2216returns a <tt>va_list</tt> element, so that the next <tt>vaarg</tt>
2217will produce the first variable argument passed to the function. Unlike
2218the C <tt>va_start</tt> macro, this intrinsic does not need to know the
2219last argument of the function, the compiler can figure that out.</p>
2220<p>Note that this intrinsic function is only legal to be called from
2221within the body of a variable argument function.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2222</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2223
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2224<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2225<div class="doc_subsubsection">
2226 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
2227</div>
2228
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2229<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2230<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2231<pre> call void (&lt;va_list&gt;)* %llvm.va_end(&lt;va_list&gt; &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2232<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2233<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
2234which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
2235or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2236<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2237<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2238<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2239<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]2240macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
2241Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
2242 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
2243with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2244</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2245
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2246<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2247<div class="doc_subsubsection">
2248 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
2249</div>
2250
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2251<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2252
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2253<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2254
2255<pre>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2256 call &lt;va_list&gt; (&lt;va_list&gt;)* %llvm.va_copy(&lt;va_list&gt; &lt;destarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2257</pre>
2258
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2259<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2260
2261<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
2262from the source argument list to the destination argument list.</p>
2263
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2264<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2265
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2266<p>The argument is the <tt>va_list</tt> to copy.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2267
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2268<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2269
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2270<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2271macro available in C. In a target-dependent way, it copies the source
2272<tt>va_list</tt> element into the returned list. This intrinsic is necessary
Chris Lattnerfcd37252004-06-21 22:52:48 +0000[diff] [blame]2273because the <tt><a href="#i_va_start">llvm.va_start</a></tt> intrinsic may be
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2274arbitrarily complex and require memory allocation, for example.</p>
2275
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2276</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2277
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2278<!-- ======================================================================= -->
2279<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2280 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
2281</div>
2282
2283<div class="doc_text">
2284
2285<p>
2286LLVM support for <a href="GarbageCollection.html">Accurate Garbage
2287Collection</a> requires the implementation and generation of these intrinsics.
2288These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
2289stack</a>, as well as garbage collector implementations that require <a
2290href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
2291Front-ends for type-safe garbage collected languages should generate these
2292intrinsics to make use of the LLVM garbage collectors. For more details, see <a
2293href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
2294</p>
2295</div>
2296
2297<!-- _______________________________________________________________________ -->
2298<div class="doc_subsubsection">
2299 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
2300</div>
2301
2302<div class="doc_text">
2303
2304<h5>Syntax:</h5>
2305
2306<pre>
2307 call void (&lt;ty&gt;**, &lt;ty2&gt;*)* %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
2308</pre>
2309
2310<h5>Overview:</h5>
2311
2312<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existance of a GC root to
2313the code generator, and allows some metadata to be associated with it.</p>
2314
2315<h5>Arguments:</h5>
2316
2317<p>The first argument specifies the address of a stack object that contains the
2318root pointer. The second pointer (which must be either a constant or a global
2319value address) contains the meta-data to be associated with the root.</p>
2320
2321<h5>Semantics:</h5>
2322
2323<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
2324location. At compile-time, the code generator generates information to allow
2325the runtime to find the pointer at GC safe points.
2326</p>
2327
2328</div>
2329
2330
2331<!-- _______________________________________________________________________ -->
2332<div class="doc_subsubsection">
2333 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
2334</div>
2335
2336<div class="doc_text">
2337
2338<h5>Syntax:</h5>
2339
2340<pre>
2341 call sbyte* (sbyte**)* %llvm.gcread(sbyte** %Ptr)
2342</pre>
2343
2344<h5>Overview:</h5>
2345
2346<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
2347locations, allowing garbage collector implementations that require read
2348barriers.</p>
2349
2350<h5>Arguments:</h5>
2351
2352<p>The argument is the address to read from, which should be an address
2353allocated from the garbage collector.</p>
2354
2355<h5>Semantics:</h5>
2356
2357<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
2358instruction, but may be replaced with substantially more complex code by the
2359garbage collector runtime, as needed.</p>
2360
2361</div>
2362
2363
2364<!-- _______________________________________________________________________ -->
2365<div class="doc_subsubsection">
2366 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
2367</div>
2368
2369<div class="doc_text">
2370
2371<h5>Syntax:</h5>
2372
2373<pre>
2374 call void (sbyte*, sbyte**)* %llvm.gcwrite(sbyte* %P1, sbyte** %P2)
2375</pre>
2376
2377<h5>Overview:</h5>
2378
2379<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
2380locations, allowing garbage collector implementations that require write
2381barriers (such as generational or reference counting collectors).</p>
2382
2383<h5>Arguments:</h5>
2384
2385<p>The first argument is the reference to store, and the second is the heap
2386location to store to.</p>
2387
2388<h5>Semantics:</h5>
2389
2390<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
2391instruction, but may be replaced with substantially more complex code by the
2392garbage collector runtime, as needed.</p>
2393
2394</div>
2395
2396
2397
2398<!-- ======================================================================= -->
2399<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2400 <a name="int_codegen">Code Generator Intrinsics</a>
2401</div>
2402
2403<div class="doc_text">
2404<p>
2405These intrinsics are provided by LLVM to expose special features that may only
2406be implemented with code generator support.
2407</p>
2408
2409</div>
2410
2411<!-- _______________________________________________________________________ -->
2412<div class="doc_subsubsection">
2413 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
2414</div>
2415
2416<div class="doc_text">
2417
2418<h5>Syntax:</h5>
2419<pre>
2420 call void* ()* %llvm.returnaddress(uint &lt;level&gt;)
2421</pre>
2422
2423<h5>Overview:</h5>
2424
2425<p>
2426The '<tt>llvm.returnaddress</tt>' intrinsic returns a target-specific value
2427indicating the return address of the current function or one of its callers.
2428</p>
2429
2430<h5>Arguments:</h5>
2431
2432<p>
2433The argument to this intrinsic indicates which function to return the address
2434for. Zero indicates the calling function, one indicates its caller, etc. The
2435argument is <b>required</b> to be a constant integer value.
2436</p>
2437
2438<h5>Semantics:</h5>
2439
2440<p>
2441The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
2442the return address of the specified call frame, or zero if it cannot be
2443identified. The value returned by this intrinsic is likely to be incorrect or 0
2444for arguments other than zero, so it should only be used for debugging purposes.
2445</p>
2446
2447<p>
2448Note that calling this intrinsic does not prevent function inlining or other
2449aggressive transformations, so the value returned may not that of the obvious
2450source-language caller.
2451</p>
2452</div>
2453
2454
2455<!-- _______________________________________________________________________ -->
2456<div class="doc_subsubsection">
2457 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
2458</div>
2459
2460<div class="doc_text">
2461
2462<h5>Syntax:</h5>
2463<pre>
2464 call void* ()* %llvm.frameaddress(uint &lt;level&gt;)
2465</pre>
2466
2467<h5>Overview:</h5>
2468
2469<p>
2470The '<tt>llvm.frameaddress</tt>' intrinsic returns the target-specific frame
2471pointer value for the specified stack frame.
2472</p>
2473
2474<h5>Arguments:</h5>
2475
2476<p>
2477The argument to this intrinsic indicates which function to return the frame
2478pointer for. Zero indicates the calling function, one indicates its caller,
2479etc. The argument is <b>required</b> to be a constant integer value.
2480</p>
2481
2482<h5>Semantics:</h5>
2483
2484<p>
2485The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
2486the frame address of the specified call frame, or zero if it cannot be
2487identified. The value returned by this intrinsic is likely to be incorrect or 0
2488for arguments other than zero, so it should only be used for debugging purposes.
2489</p>
2490
2491<p>
2492Note that calling this intrinsic does not prevent function inlining or other
2493aggressive transformations, so the value returned may not that of the obvious
2494source-language caller.
2495</p>
2496</div>
2497
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2498<!-- ======================================================================= -->
2499<div class="doc_subsection">
2500 <a name="int_os">Operating System Intrinsics</a>
2501</div>
2502
2503<div class="doc_text">
2504<p>
2505These intrinsics are provided by LLVM to support the implementation of
2506operating system level code.
2507</p>
2508
2509</div>
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2510
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2511<!-- _______________________________________________________________________ -->
2512<div class="doc_subsubsection">
2513 <a name="i_readport">'<tt>llvm.readport</tt>' Intrinsic</a>
2514</div>
2515
2516<div class="doc_text">
2517
2518<h5>Syntax:</h5>
2519<pre>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2520 call &lt;integer type&gt; (&lt;integer type&gt;)* %llvm.readport (&lt;integer type&gt; &lt;address&gt;)
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2521</pre>
2522
2523<h5>Overview:</h5>
2524
2525<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2526The '<tt>llvm.readport</tt>' intrinsic reads data from the specified hardware
2527I/O port.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2528</p>
2529
2530<h5>Arguments:</h5>
2531
2532<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2533The argument to this intrinsic indicates the hardware I/O address from which
2534to read the data. The address is in the hardware I/O address namespace (as
2535opposed to being a memory location for memory mapped I/O).
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2536</p>
2537
2538<h5>Semantics:</h5>
2539
2540<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2541The '<tt>llvm.readport</tt>' intrinsic reads data from the hardware I/O port
2542specified by <i>address</i> and returns the value. The address and return
2543value must be integers, but the size is dependent upon the platform upon which
2544the program is code generated. For example, on x86, the address must be an
2545unsigned 16 bit value, and the return value must be 8, 16, or 32 bits.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2546</p>
2547
2548</div>
2549
2550<!-- _______________________________________________________________________ -->
2551<div class="doc_subsubsection">
2552 <a name="i_writeport">'<tt>llvm.writeport</tt>' Intrinsic</a>
2553</div>
2554
2555<div class="doc_text">
2556
2557<h5>Syntax:</h5>
2558<pre>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2559 call void (&lt;integer type&gt;, &lt;integer type&gt;)*
2560 %llvm.writeport (&lt;integer type&gt; &lt;value&gt;,
2561 &lt;integer type&gt; &lt;address&gt;)
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2562</pre>
2563
2564<h5>Overview:</h5>
2565
2566<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2567The '<tt>llvm.writeport</tt>' intrinsic writes data to the specified hardware
2568I/O port.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2569</p>
2570
2571<h5>Arguments:</h5>
2572
2573<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2574The first argument is the value to write to the I/O port.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2575</p>
2576
2577<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2578The second argument indicates the hardware I/O address to which data should be
2579written. The address is in the hardware I/O address namespace (as opposed to
2580being a memory location for memory mapped I/O).
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2581</p>
2582
2583<h5>Semantics:</h5>
2584
2585<p>
2586The '<tt>llvm.writeport</tt>' intrinsic writes <i>value</i> to the I/O port
2587specified by <i>address</i>. The address and value must be integers, but the
2588size is dependent upon the platform upon which the program is code generated.
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2589For example, on x86, the address must be an unsigned 16 bit value, and the
2590value written must be 8, 16, or 32 bits in length.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2591</p>
2592
2593</div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2594
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2595<!-- _______________________________________________________________________ -->
2596<div class="doc_subsubsection">
2597 <a name="i_readio">'<tt>llvm.readio</tt>' Intrinsic</a>
2598</div>
2599
2600<div class="doc_text">
2601
2602<h5>Syntax:</h5>
2603<pre>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2604 call &lt;result&gt; (&lt;ty&gt;*)* %llvm.readio (&lt;ty&gt; * &lt;pointer&gt;)
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2605</pre>
2606
2607<h5>Overview:</h5>
2608
2609<p>
2610The '<tt>llvm.readio</tt>' intrinsic reads data from a memory mapped I/O
2611address.
2612</p>
2613
2614<h5>Arguments:</h5>
2615
2616<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2617The argument to this intrinsic is a pointer indicating the memory address from
2618which to read the data. The data must be a
2619<a href="#t_firstclass">first class</a> type.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2620</p>
2621
2622<h5>Semantics:</h5>
2623
2624<p>
2625The '<tt>llvm.readio</tt>' intrinsic reads data from a memory mapped I/O
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2626location specified by <i>pointer</i> and returns the value. The argument must
2627be a pointer, and the return value must be a
2628<a href="#t_firstclass">first class</a> type. However, certain architectures
2629may not support I/O on all first class types. For example, 32 bit processors
2630may only support I/O on data types that are 32 bits or less.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2631</p>
2632
2633<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2634This intrinsic enforces an in-order memory model for llvm.readio and
2635llvm.writeio calls on machines that use dynamic scheduling. Dynamically
2636scheduled processors may execute loads and stores out of order, re-ordering at
2637run time accesses to memory mapped I/O registers. Using these intrinsics
2638ensures that accesses to memory mapped I/O registers occur in program order.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2639</p>
2640
2641</div>
2642
2643<!-- _______________________________________________________________________ -->
2644<div class="doc_subsubsection">
2645 <a name="i_writeio">'<tt>llvm.writeio</tt>' Intrinsic</a>
2646</div>
2647
2648<div class="doc_text">
2649
2650<h5>Syntax:</h5>
2651<pre>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2652 call void (&lt;ty1&gt;, &lt;ty2&gt;*)* %llvm.writeio (&lt;ty1&gt; &lt;value&gt;, &lt;ty2&gt; * &lt;pointer&gt;)
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2653</pre>
2654
2655<h5>Overview:</h5>
2656
2657<p>
2658The '<tt>llvm.writeio</tt>' intrinsic writes data to the specified memory
2659mapped I/O address.
2660</p>
2661
2662<h5>Arguments:</h5>
2663
2664<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2665The first argument is the value to write to the memory mapped I/O location.
2666The second argument is a pointer indicating the memory address to which the
2667data should be written.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2668</p>
2669
2670<h5>Semantics:</h5>
2671
2672<p>
2673The '<tt>llvm.writeio</tt>' intrinsic writes <i>value</i> to the memory mapped
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2674I/O address specified by <i>pointer</i>. The value must be a
2675<a href="#t_firstclass">first class</a> type. However, certain architectures
2676may not support I/O on all first class types. For example, 32 bit processors
2677may only support I/O on data types that are 32 bits or less.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2678</p>
2679
2680<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2681This intrinsic enforces an in-order memory model for llvm.readio and
2682llvm.writeio calls on machines that use dynamic scheduling. Dynamically
2683scheduled processors may execute loads and stores out of order, re-ordering at
2684run time accesses to memory mapped I/O registers. Using these intrinsics
2685ensures that accesses to memory mapped I/O registers occur in program order.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2686</p>
2687
2688</div>
2689
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2690<!-- ======================================================================= -->
2691<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2692 <a name="int_libc">Standard C Library Intrinsics</a>
2693</div>
2694
2695<div class="doc_text">
2696<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2697LLVM provides intrinsics for a few important standard C library functions.
2698These intrinsics allow source-language front-ends to pass information about the
2699alignment of the pointer arguments to the code generator, providing opportunity
2700for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2701</p>
2702
2703</div>
2704
2705<!-- _______________________________________________________________________ -->
2706<div class="doc_subsubsection">
2707 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
2708</div>
2709
2710<div class="doc_text">
2711
2712<h5>Syntax:</h5>
2713<pre>
2714 call void (sbyte*, sbyte*, uint, uint)* %llvm.memcpy(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
2715 uint &lt;len&gt;, uint &lt;align&gt;)
2716</pre>
2717
2718<h5>Overview:</h5>
2719
2720<p>
2721The '<tt>llvm.memcpy</tt>' intrinsic copies a block of memory from the source
2722location to the destination location.
2723</p>
2724
2725<p>
2726Note that, unlike the standard libc function, the <tt>llvm.memcpy</tt> intrinsic
2727does not return a value, and takes an extra alignment argument.
2728</p>
2729
2730<h5>Arguments:</h5>
2731
2732<p>
2733The first argument is a pointer to the destination, the second is a pointer to
2734the source. The third argument is an (arbitrarily sized) integer argument
2735specifying the number of bytes to copy, and the fourth argument is the alignment
2736of the source and destination locations.
2737</p>
2738
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]2739<p>
2740If the call to this intrinisic has an alignment value that is not 0 or 1, then
2741the caller guarantees that the size of the copy is a multiple of the alignment
2742and that both the source and destination pointers are aligned to that boundary.
2743</p>
2744
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2745<h5>Semantics:</h5>
2746
2747<p>
2748The '<tt>llvm.memcpy</tt>' intrinsic copies a block of memory from the source
2749location to the destination location, which are not allowed to overlap. It
2750copies "len" bytes of memory over. If the argument is known to be aligned to
2751some boundary, this can be specified as the fourth argument, otherwise it should
2752be set to 0 or 1.
2753</p>
2754</div>
2755
2756
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]2757<!-- _______________________________________________________________________ -->
2758<div class="doc_subsubsection">
2759 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
2760</div>
2761
2762<div class="doc_text">
2763
2764<h5>Syntax:</h5>
2765<pre>
2766 call void (sbyte*, sbyte*, uint, uint)* %llvm.memmove(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
2767 uint &lt;len&gt;, uint &lt;align&gt;)
2768</pre>
2769
2770<h5>Overview:</h5>
2771
2772<p>
2773The '<tt>llvm.memmove</tt>' intrinsic moves a block of memory from the source
2774location to the destination location. It is similar to the '<tt>llvm.memcpy</tt>'
2775intrinsic but allows the two memory locations to overlap.
2776</p>
2777
2778<p>
2779Note that, unlike the standard libc function, the <tt>llvm.memmove</tt> intrinsic
2780does not return a value, and takes an extra alignment argument.
2781</p>
2782
2783<h5>Arguments:</h5>
2784
2785<p>
2786The first argument is a pointer to the destination, the second is a pointer to
2787the source. The third argument is an (arbitrarily sized) integer argument
2788specifying the number of bytes to copy, and the fourth argument is the alignment
2789of the source and destination locations.
2790</p>
2791
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]2792<p>
2793If the call to this intrinisic has an alignment value that is not 0 or 1, then
2794the caller guarantees that the size of the copy is a multiple of the alignment
2795and that both the source and destination pointers are aligned to that boundary.
2796</p>
2797
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]2798<h5>Semantics:</h5>
2799
2800<p>
2801The '<tt>llvm.memmove</tt>' intrinsic copies a block of memory from the source
2802location to the destination location, which may overlap. It
2803copies "len" bytes of memory over. If the argument is known to be aligned to
2804some boundary, this can be specified as the fourth argument, otherwise it should
2805be set to 0 or 1.
2806</p>
2807</div>
2808
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2809
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2810<!-- _______________________________________________________________________ -->
2811<div class="doc_subsubsection">
2812 <a name="i_memset">'<tt>llvm.memset</tt>' Intrinsic</a>
2813</div>
2814
2815<div class="doc_text">
2816
2817<h5>Syntax:</h5>
2818<pre>
2819 call void (sbyte*, ubyte, uint, uint)* %llvm.memset(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
2820 uint &lt;len&gt;, uint &lt;align&gt;)
2821</pre>
2822
2823<h5>Overview:</h5>
2824
2825<p>
2826The '<tt>llvm.memset</tt>' intrinsic fills a block of memory with a particular
2827byte value.
2828</p>
2829
2830<p>
2831Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
2832does not return a value, and takes an extra alignment argument.
2833</p>
2834
2835<h5>Arguments:</h5>
2836
2837<p>
2838The first argument is a pointer to the destination to fill, the second is the
2839byte value to fill it with, the third argument is an (arbitrarily sized) integer
2840argument specifying the number of bytes to fill, and the fourth argument is the
2841known alignment of destination location.
2842</p>
2843
2844<p>
2845If the call to this intrinisic has an alignment value that is not 0 or 1, then
2846the caller guarantees that the size of the copy is a multiple of the alignment
2847and that the destination pointer is aligned to that boundary.
2848</p>
2849
2850<h5>Semantics:</h5>
2851
2852<p>
2853The '<tt>llvm.memset</tt>' intrinsic fills "len" bytes of memory starting at the
2854destination location. If the argument is known to be aligned to some boundary,
2855this can be specified as the fourth argument, otherwise it should be set to 0 or
28561.
2857</p>
2858</div>
2859
2860
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]2861<!-- _______________________________________________________________________ -->
2862<div class="doc_subsubsection">
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]2863 <a name="i_isunordered">'<tt>llvm.isunordered</tt>' Intrinsic</a>
2864</div>
2865
2866<div class="doc_text">
2867
2868<h5>Syntax:</h5>
2869<pre>
2870 call bool (&lt;float or double&gt;, &lt;float or double&gt;)* %llvm.isunordered(&lt;float or double&gt; Val1,
2871 &lt;float or double&gt; Val2)
2872</pre>
2873
2874<h5>Overview:</h5>
2875
2876<p>
2877The '<tt>llvm.isunordered</tt>' intrinsic returns true if either or both of the
2878specified floating point values is a NAN.
2879</p>
2880
2881<h5>Arguments:</h5>
2882
2883<p>
2884The arguments are floating point numbers of the same type.
2885</p>
2886
2887<h5>Semantics:</h5>
2888
2889<p>
2890If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
2891false.
2892</p>
2893</div>
2894
2895
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]2896
2897
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2898<!-- ======================================================================= -->
2899<div class="doc_subsection">
2900 <a name="int_debugger">Debugger Intrinsics</a>
2901</div>
2902
2903<div class="doc_text">
2904<p>
2905The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
2906are described in the <a
2907href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
2908Debugging</a> document.
2909</p>
2910</div>
2911
2912
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2913<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2914<hr>
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2921 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
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