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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / c3f5976112c2785f192c4ef95404627020d33ec3 / . / 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
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame^]241 <li>Constants, which are described in <a href="#constants">section about
242 constants</a></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<!-- ======================================================================= -->
781<div class="doc_subsection"> <a name="simpleconstants">Simple Constants</a>
782</div>
783
784<div class="doc_text">
785
786<dl>
787 <dt><b>Boolean constants</b></dt>
788
789 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
790 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
791 </dd>
792
793 <dt><b>Integer constants</b></dt>
794
795 <dd>Standard integers (such as '4') are constants of <a
796 href="#t_integer">integer</a> type. Negative numbers may be used with signed
797 integer types.
798 </dd>
799
800 <dt><b>Floating point constants</b></dt>
801
802 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
803 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
804 notation. etc. Floating point constants have an optional hexadecimal
805 notation (see below). Floating point constants must have a <a
806 href="#t_floating">floating point</a> type. </dd>
807
808 <dt><b>Null pointer constants</b></dt>
809
810 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant,
811 and must be of <a href="#t_pointer">pointer type</a>.</dd>
812
813</dl>
814
815<p>The one non-intuitive notation for constants is the optional hexidecimal form
816of floating point constants. For example, the form '<tt>double
8170x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
8184.5e+15</tt>'. The only time hexadecimal floating point constants are required
819(and the only time that they are generated by the disassembler) is when an FP
820constant has to be emitted that is not representable as a decimal floating point
821number exactly. For example, NaN's, infinities, and other special cases are
822represented in their IEEE hexadecimal format so that assembly and disassembly do
823not cause any bits to change in the constants.</p>
824
825</div>
826
827<!-- ======================================================================= -->
828<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
829</div>
830
831<div class="doc_text">
832
833<dl>
834 <dt><b>Structure constants</b></dt>
835
836 <dd>Structure constants are represented with notation similar to structure
837 type definitions (a comma separated list of elements, surrounded by braces
838 (<tt>{}</tt>). For example: "<tt>{ int 4, float 17.0 }</tt>". Structure
839 constants must have <a href="#t_struct">structure type</a>, and the number and
840 types of elements must match those specified by the type.
841 </dd>
842
843 <dt><b>Array constants</b></dt>
844
845 <dd>Array constants are represented with notation similar to array type
846 definitions (a comma separated list of elements, surrounded by square brackets
847 (<tt>[]</tt>). For example: "<tt>[ int 42, int 11, int 74 ]</tt>". Array
848 constants must have <a href="#t_array">array type</a>, and the number and
849 types of elements must match those specified by the type.
850 </dd>
851
852 <dt><b>Packed constants</b></dt>
853
854 <dd>Packed constants are represented with notation similar to packed type
855 definitions (a comma separated list of elements, surrounded by
856 less-than/greater-than's (<tt>&lt;&gt;</tt>). For example: "<tt>&lt; int 42,
857 int 11, int 74, int 100 &gt;</tt>". Packed constants must have <a
858 href="#t_packed">packed type</a>, and the number and types of elements must
859 match those specified by the type.
860 </dd>
861
862 <dt><b>Zero initialization</b></dt>
863
864 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
865 value to zero of <em>any</em> type, including scalar and aggregate types.
866 This is often used to avoid having to print large zero initializers (e.g. for
867 large arrays), and is always exactly equivalent to using explicit zero
868 initializers.
869 </dd>
870</dl>
871
872</div>
873
874<!-- ======================================================================= -->
875<div class="doc_subsection">
876 <a name="globalconstants">Global Variable and Function Addresses</a>
877</div>
878
879<div class="doc_text">
880
881<p>The addresses of <a href="#globalvars">global variables</a> and <a
882href="#functionstructure">functions</a> are always implicitly valid (link-time)
883constants. These constants explicitly referenced when the <a
884href="#identifiers">identifier for the global</a> is used, and always have <a
885href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
886file:</p>
887
888<pre>
889 %X = global int 17
890 %Y = global int 42
891 %Z = global [2 x int*] [ int* %X, int* %Y ]
892</pre>
893
894</div>
895
896<!-- ======================================================================= -->
897<div class="doc_subsection"><a name="undefvalues">Undefined Values</a>
898</div>
899
900<div class="doc_text">
901
902<p>The string '<tt>undef</tt>' is recognized as a filler that has no specified
903value. Undefined values may be of any type, and be used anywhere a constant
904is.</p>
905
906<p>Undefined values are used to indicate the compiler that the program is well
907defined no matter what value is used, giving it more freedom.</p>
908
909</div>
910
911<!-- ======================================================================= -->
912<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
913</div>
914
915<div class="doc_text">
916
917<p>Constant expressions are used to allow expressions involving other constants
918to be used as constants. Constant expressions may be of any <a
919href="#t_firstclass">first class</a> type, and may involve any LLVM operation
920that does not have side effects (e.g. load and call are not supported). The
921following is the syntax for constant expressions:</p>
922
923<dl>
924 <dt><b><tt>cast ( CST to TYPE )</tt></b></dt>
925
926 <dd>Cast a constant to another type.</dd>
927
928 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
929
930 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
931 constants. As with the <a href="#i_getelementptr">getelementptr</a>
932 instruction, the index list may have zero or more indexes, which are required
933 to make sense for the type of "CSTPTR".</dd>
934
935 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
936
937 <dd>Perform the specied operation of the LHS and RHS constants. OPCODE may be
938 any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
939 binary</a> operations. The constraints on operands are the same as those for
940 the corresponding instruction (e.g. no bitwise operations on floating point
941 are allowed).</dd>
942
943</dl>
944
945</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]946
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]947<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]948<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
949<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame^]950
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]951<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame^]952
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]953<p>The LLVM instruction set consists of several different
954classifications of instructions: <a href="#terminators">terminator
955instructions</a>, <a href="#binaryops">binary instructions</a>, <a
956 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
957instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame^]958
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]959</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame^]960
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]961<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]962<div class="doc_subsection"> <a name="terminators">Terminator
963Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame^]964
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]965<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame^]966
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]967<p>As mentioned <a href="#functionstructure">previously</a>, every
968basic block in a program ends with a "Terminator" instruction, which
969indicates which block should be executed after the current block is
970finished. These terminator instructions typically yield a '<tt>void</tt>'
971value: they produce control flow, not values (the one exception being
972the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame^]973
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]974<p>There are five different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]975 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
976instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]977the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
978 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
979 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame^]980
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]981</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame^]982
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]983<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]984<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
985Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]986<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]987<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]988<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]989 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]990</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]991<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]992<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
993value) from a function, back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]994<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]995returns a value and then causes control flow, and one that just causes
996control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]997<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]998<p>The '<tt>ret</tt>' instruction may return any '<a
999 href="#t_firstclass">first class</a>' type. Notice that a function is
1000not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1001instruction inside of the function that returns a value that does not
1002match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1003<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1004<p>When the '<tt>ret</tt>' instruction is executed, control flow
1005returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1006 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1007the instruction after the call. If the caller was an "<a
1008 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
1009at the beginning "normal" of the destination block. If the instruction
1010returns a value, that value shall set the call or invoke instruction's
1011return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1012<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1013<pre> ret int 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1014 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1015</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1016</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1017<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1018<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1019<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1020<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1021<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]1022</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1023<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1024<p>The '<tt>br</tt>' instruction is used to cause control flow to
1025transfer to a different basic block in the current function. There are
1026two forms of this instruction, corresponding to a conditional branch
1027and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1028<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1029<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1030single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1031unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1032value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1033<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1034<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1035argument is evaluated. If the value is <tt>true</tt>, control flows
1036to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1037control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1038<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1039<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
1040 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]1041</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1042<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1043<div class="doc_subsubsection">
1044 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1045</div>
1046
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1047<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1048<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1049
1050<pre>
1051 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1052</pre>
1053
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1054<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1055
1056<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1057several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1058instruction, allowing a branch to occur to one of many possible
1059destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1060
1061
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1062<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1063
1064<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1065comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1066an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1067table is not allowed to contain duplicate constant entries.</p>
1068
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1069<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1070
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1071<p>The <tt>switch</tt> instruction specifies a table of values and
1072destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1073table is searched for the given value. If the value is found, control flow is
1074transfered to the corresponding destination; otherwise, control flow is
1075transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1076
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1077<h5>Implementation:</h5>
1078
1079<p>Depending on properties of the target machine and the particular
1080<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1081ways. For example, it could be generated as a series of chained conditional
1082branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1083
1084<h5>Example:</h5>
1085
1086<pre>
1087 <i>; Emulate a conditional br instruction</i>
1088 %Val = <a href="#i_cast">cast</a> bool %value to int
1089 switch int %Val, label %truedest [int 0, label %falsedest ]
1090
1091 <i>; Emulate an unconditional br instruction</i>
1092 switch uint 0, label %dest [ ]
1093
1094 <i>; Implement a jump table:</i>
1095 switch uint %val, label %otherwise [ uint 0, label %onzero
1096 uint 1, label %onone
1097 uint 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1098</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1099</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1100<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1101<div class="doc_subsubsection"> <a name="i_invoke">'<tt>invoke</tt>'
1102Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1103<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1104<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1105<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]1106<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1107<p>The '<tt>invoke</tt>' instruction causes control to transfer to a
1108specified function, with the possibility of control flow transfer to
1109either the '<tt>normal</tt>' <tt>label</tt> label or the '<tt>exception</tt>'<tt>label</tt>.
1110If the callee function returns with the "<tt><a href="#i_ret">ret</a></tt>"
1111instruction, control flow will return to the "normal" label. If the
1112callee (or any indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
1113instruction, control is interrupted, and continued at the dynamically
1114nearest "except" label.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1115<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1116<p>This instruction requires several arguments:</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1117<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1118 <li>'<tt>ptr to function ty</tt>': shall be the signature of the
1119pointer to function value being invoked. In most cases, this is a
1120direct function invocation, but indirect <tt>invoke</tt>s are just as
1121possible, branching off an arbitrary pointer to function value. </li>
1122 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer
1123to a function to be invoked. </li>
1124 <li>'<tt>function args</tt>': argument list whose types match the
1125function signature argument types. If the function signature indicates
1126the function accepts a variable number of arguments, the extra
1127arguments can be specified. </li>
1128 <li>'<tt>normal label</tt>': the label reached when the called
1129function executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1130 <li>'<tt>exception label</tt>': the label reached when a callee
1131returns with the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1132</ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1133<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1134<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1135 href="#i_call">call</a></tt>' instruction in most regards. The
1136primary difference is that it establishes an association with a label,
1137which is used by the runtime library to unwind the stack.</p>
1138<p>This instruction is used in languages with destructors to ensure
1139that proper cleanup is performed in the case of either a <tt>longjmp</tt>
1140or a thrown exception. Additionally, this is important for
1141implementation of '<tt>catch</tt>' clauses in high-level languages that
1142support them.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1143<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1144<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]1145</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1146</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1147
1148
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1149<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1150
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1151<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1152Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1153
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1154<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1155
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1156<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1157<pre>
1158 unwind
1159</pre>
1160
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1161<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1162
1163<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1164at the first callee in the dynamic call stack which used an <a
1165href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1166primarily used to implement exception handling.</p>
1167
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1168<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1169
1170<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1171immediately halt. The dynamic call stack is then searched for the first <a
1172href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1173execution continues at the "exceptional" destination block specified by the
1174<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1175dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1176</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1177
1178<!-- _______________________________________________________________________ -->
1179
1180<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1181Instruction</a> </div>
1182
1183<div class="doc_text">
1184
1185<h5>Syntax:</h5>
1186<pre>
1187 unreachable
1188</pre>
1189
1190<h5>Overview:</h5>
1191
1192<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1193instruction is used to inform the optimizer that a particular portion of the
1194code is not reachable. This can be used to indicate that the code after a
1195no-return function cannot be reached, and other facts.</p>
1196
1197<h5>Semantics:</h5>
1198
1199<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1200</div>
1201
1202
1203
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1204<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1205<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1206<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1207<p>Binary operators are used to do most of the computation in a
1208program. They require two operands, execute an operation on them, and
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1209produce a single value. Although, that single value might represent
1210multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1211The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1212necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1213<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1214</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1215<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1216<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1217Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1218<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1219<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1220<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]1221</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1222<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1223<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1224<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1225<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1226 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1227 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1228Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1229<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1230<p>The value produced is the integer or floating point sum of the two
1231operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1232<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1233<pre> &lt;result&gt; = add int 4, %var <i>; yields {int}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1234</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1235</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1236<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1237<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1238Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1239<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1240<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1241<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]1242</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1243<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1244<p>The '<tt>sub</tt>' instruction returns the difference of its two
1245operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1246<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1247instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1248<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1249<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1250 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1251values.
1252This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1253Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1254<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1255<p>The value produced is the integer or floating point difference of
1256the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1257<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1258<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]1259 &lt;result&gt; = sub int 0, %val <i>; yields {int}:result = -%var</i>
1260</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1261</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1262<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1263<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1264Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1265<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1266<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1267<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]1268</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1269<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1270<p>The '<tt>mul</tt>' instruction returns the product of its two
1271operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1272<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1273<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1274 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1275values.
1276This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1277Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1278<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1279<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1280two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1281<p>There is no signed vs unsigned multiplication. The appropriate
1282action is taken based on the type of the operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1283<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1284<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]1285</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1286</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1287<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1288<div class="doc_subsubsection"> <a name="i_div">'<tt>div</tt>'
1289Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1290<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1291<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1292<pre> &lt;result&gt; = div &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1293</pre>
1294<h5>Overview:</h5>
1295<p>The '<tt>div</tt>' instruction returns the quotient of its two
1296operands.</p>
1297<h5>Arguments:</h5>
1298<p>The two arguments to the '<tt>div</tt>' instruction must be either <a
1299 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1300values.
1301This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1302Both arguments must have identical types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1303<h5>Semantics:</h5>
1304<p>The value produced is the integer or floating point quotient of the
1305two operands.</p>
1306<h5>Example:</h5>
1307<pre> &lt;result&gt; = div int 4, %var <i>; yields {int}:result = 4 / %var</i>
1308</pre>
1309</div>
1310<!-- _______________________________________________________________________ -->
1311<div class="doc_subsubsection"> <a name="i_rem">'<tt>rem</tt>'
1312Instruction</a> </div>
1313<div class="doc_text">
1314<h5>Syntax:</h5>
1315<pre> &lt;result&gt; = rem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1316</pre>
1317<h5>Overview:</h5>
1318<p>The '<tt>rem</tt>' instruction returns the remainder from the
1319division of its two operands.</p>
1320<h5>Arguments:</h5>
1321<p>The two arguments to the '<tt>rem</tt>' instruction must be either <a
1322 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1323values.
1324This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1325Both arguments must have identical types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1326<h5>Semantics:</h5>
1327<p>This returns the <i>remainder</i> of a division (where the result
1328has the same sign as the divisor), not the <i>modulus</i> (where the
1329result has the same sign as the dividend) of a value. For more
1330information about the difference, see: <a
1331 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1332Math Forum</a>.</p>
1333<h5>Example:</h5>
1334<pre> &lt;result&gt; = rem int 4, %var <i>; yields {int}:result = 4 % %var</i>
1335</pre>
1336</div>
1337<!-- _______________________________________________________________________ -->
1338<div class="doc_subsubsection"> <a name="i_setcc">'<tt>set<i>cc</i></tt>'
1339Instructions</a> </div>
1340<div class="doc_text">
1341<h5>Syntax:</h5>
1342<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]1343 &lt;result&gt; = setne &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1344 &lt;result&gt; = setlt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1345 &lt;result&gt; = setgt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1346 &lt;result&gt; = setle &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1347 &lt;result&gt; = setge &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1348</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1349<h5>Overview:</h5>
1350<p>The '<tt>set<i>cc</i></tt>' family of instructions returns a boolean
1351value based on a comparison of their two operands.</p>
1352<h5>Arguments:</h5>
1353<p>The two arguments to the '<tt>set<i>cc</i></tt>' instructions must
1354be of <a href="#t_firstclass">first class</a> type (it is not possible
1355to compare '<tt>label</tt>'s, '<tt>array</tt>'s, '<tt>structure</tt>'
1356or '<tt>void</tt>' values, etc...). Both arguments must have identical
1357types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1358<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1359<p>The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1360value if both operands are equal.<br>
1361The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1362value if both operands are unequal.<br>
1363The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1364value if the first operand is less than the second operand.<br>
1365The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1366value if the first operand is greater than the second operand.<br>
1367The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1368value if the first operand is less than or equal to the second operand.<br>
1369The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1370value if the first operand is greater than or equal to the second
1371operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1372<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1373<pre> &lt;result&gt; = seteq int 4, 5 <i>; yields {bool}:result = false</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1374 &lt;result&gt; = setne float 4, 5 <i>; yields {bool}:result = true</i>
1375 &lt;result&gt; = setlt uint 4, 5 <i>; yields {bool}:result = true</i>
1376 &lt;result&gt; = setgt sbyte 4, 5 <i>; yields {bool}:result = false</i>
1377 &lt;result&gt; = setle sbyte 4, 5 <i>; yields {bool}:result = true</i>
1378 &lt;result&gt; = setge sbyte 4, 5 <i>; yields {bool}:result = false</i>
1379</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1380</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1381<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1382<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1383Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1384<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1385<p>Bitwise binary operators are used to do various forms of
1386bit-twiddling in a program. They are generally very efficient
1387instructions, and can commonly be strength reduced from other
1388instructions. They require two operands, execute an operation on them,
1389and produce a single value. The resulting value of the bitwise binary
1390operators is always the same type as its first operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1391</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1392<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1393<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1394Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1395<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1396<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1397<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]1398</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1399<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1400<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1401its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1402<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1403<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1404 href="#t_integral">integral</a> values. Both arguments must have
1405identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1406<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1407<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1408<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1409<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1410<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1411 <tbody>
1412 <tr>
1413 <td>In0</td>
1414 <td>In1</td>
1415 <td>Out</td>
1416 </tr>
1417 <tr>
1418 <td>0</td>
1419 <td>0</td>
1420 <td>0</td>
1421 </tr>
1422 <tr>
1423 <td>0</td>
1424 <td>1</td>
1425 <td>0</td>
1426 </tr>
1427 <tr>
1428 <td>1</td>
1429 <td>0</td>
1430 <td>0</td>
1431 </tr>
1432 <tr>
1433 <td>1</td>
1434 <td>1</td>
1435 <td>1</td>
1436 </tr>
1437 </tbody>
1438</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1439</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1440<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1441<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]1442 &lt;result&gt; = and int 15, 40 <i>; yields {int}:result = 8</i>
1443 &lt;result&gt; = and int 4, 8 <i>; yields {int}:result = 0</i>
1444</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1445</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1446<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1447<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1448<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1449<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1450<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]1451</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1452<h5>Overview:</h5>
1453<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1454or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1455<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1456<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1457 href="#t_integral">integral</a> values. Both arguments must have
1458identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1459<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1460<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1461<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1462<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1463<table border="1" cellspacing="0" cellpadding="4">
1464 <tbody>
1465 <tr>
1466 <td>In0</td>
1467 <td>In1</td>
1468 <td>Out</td>
1469 </tr>
1470 <tr>
1471 <td>0</td>
1472 <td>0</td>
1473 <td>0</td>
1474 </tr>
1475 <tr>
1476 <td>0</td>
1477 <td>1</td>
1478 <td>1</td>
1479 </tr>
1480 <tr>
1481 <td>1</td>
1482 <td>0</td>
1483 <td>1</td>
1484 </tr>
1485 <tr>
1486 <td>1</td>
1487 <td>1</td>
1488 <td>1</td>
1489 </tr>
1490 </tbody>
1491</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1492</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1493<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1494<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]1495 &lt;result&gt; = or int 15, 40 <i>; yields {int}:result = 47</i>
1496 &lt;result&gt; = or int 4, 8 <i>; yields {int}:result = 12</i>
1497</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1498</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1499<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1500<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
1501Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1502<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1503<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1504<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]1505</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1506<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1507<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
1508or of its two operands. The <tt>xor</tt> is used to implement the
1509"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1510<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1511<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1512 href="#t_integral">integral</a> values. Both arguments must have
1513identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1514<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1515<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1516<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1517<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1518<table border="1" cellspacing="0" cellpadding="4">
1519 <tbody>
1520 <tr>
1521 <td>In0</td>
1522 <td>In1</td>
1523 <td>Out</td>
1524 </tr>
1525 <tr>
1526 <td>0</td>
1527 <td>0</td>
1528 <td>0</td>
1529 </tr>
1530 <tr>
1531 <td>0</td>
1532 <td>1</td>
1533 <td>1</td>
1534 </tr>
1535 <tr>
1536 <td>1</td>
1537 <td>0</td>
1538 <td>1</td>
1539 </tr>
1540 <tr>
1541 <td>1</td>
1542 <td>1</td>
1543 <td>0</td>
1544 </tr>
1545 </tbody>
1546</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1547</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1548<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1549<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1550<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]1551 &lt;result&gt; = xor int 15, 40 <i>; yields {int}:result = 39</i>
1552 &lt;result&gt; = xor int 4, 8 <i>; yields {int}:result = 12</i>
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1553 &lt;result&gt; = xor int %V, -1 <i>; yields {int}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1554</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1555</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1556<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1557<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
1558Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1559<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1560<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1561<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]1562</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1563<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1564<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
1565the left a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1566<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1567<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1568 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1569type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1570<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1571<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]1572<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1573<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]1574 &lt;result&gt; = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
1575 &lt;result&gt; = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
1576</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1577</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1578<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1579<div class="doc_subsubsection"> <a name="i_shr">'<tt>shr</tt>'
1580Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1581<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1582<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1583<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]1584</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1585<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1586<p>The '<tt>shr</tt>' instruction returns the first operand shifted to
1587the right a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1588<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1589<p>The first argument to the '<tt>shr</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1590 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1591type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1592<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1593<p>If the first argument is a <a href="#t_signed">signed</a> type, the
1594most significant bit is duplicated in the newly free'd bit positions.
1595If the first argument is unsigned, zero bits shall fill the empty
1596positions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1597<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1598<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]1599 &lt;result&gt; = shr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1600 &lt;result&gt; = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
Chris Lattner8c6bb902003-06-18 21:30:51 +0000[diff] [blame]1601 &lt;result&gt; = shr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i>
1602 &lt;result&gt; = shr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1603</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1604</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1605<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1606<div class="doc_subsection"> <a name="memoryops">Memory Access
1607Operations</a></div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1608<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1609<p>A key design point of an SSA-based representation is how it
1610represents memory. In LLVM, no memory locations are in SSA form, which
1611makes things very simple. This section describes how to read, write,
1612allocate and free memory in LLVM.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1613</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1614<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1615<div class="doc_subsubsection"> <a name="i_malloc">'<tt>malloc</tt>'
1616Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1617<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1618<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1619<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]1620 &lt;result&gt; = malloc &lt;type&gt; <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1621</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1622<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1623<p>The '<tt>malloc</tt>' instruction allocates memory from the system
1624heap and returns a pointer to it.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1625<h5>Arguments:</h5>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]1626<p>The '<tt>malloc</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
1627bytes of memory from the operating system and returns a pointer of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1628appropriate type to the program. The second form of the instruction is
1629a shorter version of the first instruction that defaults to allocating
1630one element.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1631<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1632<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1633<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
1634a pointer is returned.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1635<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1636<pre> %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1637
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1638 %size = <a
1639 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]1640 %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i>
1641 %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1642</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1643</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1644<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1645<div class="doc_subsubsection"> <a name="i_free">'<tt>free</tt>'
1646Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1647<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1648<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1649<pre> free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1650</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1651<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1652<p>The '<tt>free</tt>' instruction returns memory back to the unused
1653memory heap, to be reallocated in the future.</p>
1654<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1655<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1656<p>'<tt>value</tt>' shall be a pointer value that points to a value
1657that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
1658instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1659<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1660<p>Access to the memory pointed to by the pointer is not longer defined
1661after this instruction executes.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1662<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1663<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]1664 free [4 x ubyte]* %array
1665</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1666</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1667<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1668<div class="doc_subsubsection"> <a name="i_alloca">'<tt>alloca</tt>'
1669Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1670<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1671<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1672<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]1673 &lt;result&gt; = alloca &lt;type&gt; <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1674</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1675<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1676<p>The '<tt>alloca</tt>' instruction allocates memory on the current
1677stack frame of the procedure that is live until the current function
1678returns to its caller.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1679<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1680<p>The the '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
1681bytes of memory on the runtime stack, returning a pointer of the
1682appropriate type to the program. The second form of the instruction is
1683a shorter version of the first that defaults to allocating one element.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1684<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1685<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1686<p>Memory is allocated, a pointer is returned. '<tt>alloca</tt>'d
1687memory is automatically released when the function returns. The '<tt>alloca</tt>'
1688instruction is commonly used to represent automatic variables that must
1689have an address available. When the function returns (either with the <tt><a
1690 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]1691instructions), the memory is reclaimed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1692<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1693<pre> %ptr = alloca int <i>; yields {int*}:ptr</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1694 %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1695</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1696</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1697<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1698<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
1699Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1700<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1701<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1702<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]1703<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1704<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1705<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1706<p>The argument to the '<tt>load</tt>' instruction specifies the memory
1707address to load from. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]1708 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1709marked as <tt>volatile</tt> then the optimizer is not allowed to modify
1710the number or order of execution of this <tt>load</tt> with other
1711volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
1712instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1713<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1714<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1715<h5>Examples:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1716<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
1717 <a
1718 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1719 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
1720</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1721</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1722<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1723<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
1724Instruction</a> </div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1725<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1726<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]1727 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]1728</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1729<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1730<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1731<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1732<p>There are two arguments to the '<tt>store</tt>' instruction: a value
1733to store and an address to store it into. The type of the '<tt>&lt;pointer&gt;</tt>'
1734operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
1735operand. If the <tt>store</tt> is marked as <tt>volatile</tt> then the
1736optimizer is not allowed to modify the number or order of execution of
1737this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
1738 href="#i_store">store</a></tt> instructions.</p>
1739<h5>Semantics:</h5>
1740<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
1741at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1742<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1743<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
1744 <a
1745 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1746 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
1747</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1748<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1749<div class="doc_subsubsection">
1750 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
1751</div>
1752
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1753<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1754<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1755<pre>
1756 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
1757</pre>
1758
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1759<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1760
1761<p>
1762The '<tt>getelementptr</tt>' instruction is used to get the address of a
1763subelement of an aggregate data structure.</p>
1764
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1765<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1766
1767<p>This instruction takes a list of integer constants that indicate what
1768elements of the aggregate object to index to. The actual types of the arguments
1769provided depend on the type of the first pointer argument. The
1770'<tt>getelementptr</tt>' instruction is used to index down through the type
1771levels of a structure. When indexing into a structure, only <tt>uint</tt>
1772integer constants are allowed. When indexing into an array or pointer
1773<tt>int</tt> and <tt>long</tt> indexes are allowed of any sign.</p>
1774
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1775<p>For example, let's consider a C code fragment and how it gets
1776compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1777
1778<pre>
1779 struct RT {
1780 char A;
1781 int B[10][20];
1782 char C;
1783 };
1784 struct ST {
1785 int X;
1786 double Y;
1787 struct RT Z;
1788 };
1789
1790 int *foo(struct ST *s) {
1791 return &amp;s[1].Z.B[5][13];
1792 }
1793</pre>
1794
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1795<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1796
1797<pre>
1798 %RT = type { sbyte, [10 x [20 x int]], sbyte }
1799 %ST = type { int, double, %RT }
1800
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]1801 implementation
1802
1803 int* %foo(%ST* %s) {
1804 entry:
1805 %reg = getelementptr %ST* %s, int 1, uint 2, uint 1, int 5, int 13
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1806 ret int* %reg
1807 }
1808</pre>
1809
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1810<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1811
1812<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]1813on the pointer type that is being index into. <a href="#t_pointer">Pointer</a>
1814and <a href="#t_array">array</a> types require <tt>uint</tt>, <tt>int</tt>,
1815<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]1816types require <tt>uint</tt> <b>constants</b>.</p>
1817
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1818<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]1819type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT
1820}</tt>' type, a structure. The second index indexes into the third element of
1821the structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]],
1822sbyte }</tt>' type, another structure. The third index indexes into the second
1823element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an
1824array. The two dimensions of the array are subscripted into, yielding an
1825'<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction return a pointer
1826to this element, thus computing a value of '<tt>int*</tt>' type.</p>
1827
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1828<p>Note that it is perfectly legal to index partially through a
1829structure, returning a pointer to an inner element. Because of this,
1830the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1831
1832<pre>
1833 int* "foo"(%ST* %s) {
1834 %t1 = getelementptr %ST* %s, int 1 <i>; yields %ST*:%t1</i>
1835 %t2 = getelementptr %ST* %t1, int 0, uint 2 <i>; yields %RT*:%t2</i>
1836 %t3 = getelementptr %RT* %t2, int 0, uint 1 <i>; yields [10 x [20 x int]]*:%t3</i>
1837 %t4 = getelementptr [10 x [20 x int]]* %t3, int 0, int 5 <i>; yields [20 x int]*:%t4</i>
1838 %t5 = getelementptr [20 x int]* %t4, int 0, int 13 <i>; yields int*:%t5</i>
1839 ret int* %t5
1840 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1841</pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1842<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1843<pre>
1844 <i>; yields [12 x ubyte]*:aptr</i>
1845 %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, uint 1
1846</pre>
1847
1848</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1849<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1850<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1851<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1852<p>The instructions in this category are the "miscellaneous"
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1853instructions, which defy better classification.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1854</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1855<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1856<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
1857Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1858<div class="doc_text">
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1859<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1860<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]1861<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1862<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
1863the SSA graph representing the function.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1864<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1865<p>The type of the incoming values are specified with the first type
1866field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
1867as arguments, with one pair for each predecessor basic block of the
1868current block. Only values of <a href="#t_firstclass">first class</a>
1869type may be used as the value arguments to the PHI node. Only labels
1870may be used as the label arguments.</p>
1871<p>There must be no non-phi instructions between the start of a basic
1872block and the PHI instructions: i.e. PHI instructions must be first in
1873a basic block.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1874<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1875<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
1876value specified by the parameter, depending on which basic block we
1877came from in the last <a href="#terminators">terminator</a> instruction.</p>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1878<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1879<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]1880</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1881
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1882<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1883<div class="doc_subsubsection">
1884 <a name="i_cast">'<tt>cast .. to</tt>' Instruction</a>
1885</div>
1886
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1887<div class="doc_text">
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1888
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1889<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1890
1891<pre>
1892 &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]1893</pre>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1894
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1895<h5>Overview:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1896
1897<p>
1898The '<tt>cast</tt>' instruction is used as the primitive means to convert
1899integers to floating point, change data type sizes, and break type safety (by
1900casting pointers).
1901</p>
1902
1903
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1904<h5>Arguments:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1905
1906<p>
1907The '<tt>cast</tt>' instruction takes a value to cast, which must be a first
1908class value, and a type to cast it to, which must also be a <a
1909href="#t_firstclass">first class</a> type.
1910</p>
1911
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1912<h5>Semantics:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1913
1914<p>
1915This instruction follows the C rules for explicit casts when determining how the
1916data being cast must change to fit in its new container.
1917</p>
1918
1919<p>
1920When casting to bool, any value that would be considered true in the context of
1921a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' values,
1922all else are '<tt>false</tt>'.
1923</p>
1924
1925<p>
1926When extending an integral value from a type of one signness to another (for
1927example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value is sign-extended if the
1928<b>source</b> value is signed, and zero-extended if the source value is
1929unsigned. <tt>bool</tt> values are always zero extended into either zero or
1930one.
1931</p>
1932
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1933<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1934
1935<pre>
1936 %X = cast int 257 to ubyte <i>; yields ubyte:1</i>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame]1937 %Y = cast int 123 to bool <i>; yields bool:true</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1938</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1939</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]1940
1941<!-- _______________________________________________________________________ -->
1942<div class="doc_subsubsection">
1943 <a name="i_select">'<tt>select</tt>' Instruction</a>
1944</div>
1945
1946<div class="doc_text">
1947
1948<h5>Syntax:</h5>
1949
1950<pre>
1951 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
1952</pre>
1953
1954<h5>Overview:</h5>
1955
1956<p>
1957The '<tt>select</tt>' instruction is used to choose one value based on a
1958condition, without branching.
1959</p>
1960
1961
1962<h5>Arguments:</h5>
1963
1964<p>
1965The '<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.
1966</p>
1967
1968<h5>Semantics:</h5>
1969
1970<p>
1971If the boolean condition evaluates to true, the instruction returns the first
1972value argument, otherwise it returns the second value argument.
1973</p>
1974
1975<h5>Example:</h5>
1976
1977<pre>
1978 %X = select bool true, ubyte 17, ubyte 42 <i>; yields ubyte:17</i>
1979</pre>
1980</div>
1981
1982
1983
1984
1985
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1986<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1987<div class="doc_subsubsection"> <a name="i_call">'<tt>call</tt>'
1988Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1989<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1990<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1991<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]1992<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1993<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1994<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1995<p>This instruction requires several arguments:</p>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1996<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1997 <li>
1998 <p>'<tt>ty</tt>': shall be the signature of the pointer to function
1999value being invoked. The argument types must match the types implied
2000by this signature.</p>
2001 </li>
2002 <li>
2003 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a
2004function to be invoked. In most cases, this is a direct function
2005invocation, but indirect <tt>call</tt>s are just as possible,
2006calling an arbitrary pointer to function values.</p>
2007 </li>
2008 <li>
2009 <p>'<tt>function args</tt>': argument list whose types match the
2010function signature argument types. If the function signature
2011indicates the function accepts a variable number of arguments, the
2012extra arguments can be specified.</p>
2013 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2014</ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2015<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2016<p>The '<tt>call</tt>' instruction is used to cause control flow to
2017transfer to a specified function, with its incoming arguments bound to
2018the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
2019instruction in the called function, control flow continues with the
2020instruction after the function call, and the return value of the
2021function is bound to the result argument. This is a simpler case of
2022the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2023<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2024<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]2025</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2026
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2027<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2028<div class="doc_subsubsection">
2029 <a name="i_vanext">'<tt>vanext</tt>' Instruction</a>
2030</div>
2031
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2032<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2033
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2034<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2035
2036<pre>
2037 &lt;resultarglist&gt; = vanext &lt;va_list&gt; &lt;arglist&gt;, &lt;argty&gt;
2038</pre>
2039
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2040<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2041
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2042<p>The '<tt>vanext</tt>' instruction is used to access arguments passed
2043through the "variable argument" area of a function call. It is used to
2044implement the <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2045
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2046<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2047
2048<p>This instruction takes a <tt>va_list</tt> value and the type of the
2049argument. It returns another <tt>va_list</tt>. The actual type of
2050<tt>va_list</tt> may be defined differently for different targets. Most targets
2051use a <tt>va_list</tt> type of <tt>sbyte*</tt> or some other pointer type.</p>
2052
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2053<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2054
2055<p>The '<tt>vanext</tt>' instruction advances the specified <tt>va_list</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2056past an argument of the specified type. In conjunction with the <a
2057 href="#i_vaarg"><tt>vaarg</tt></a> instruction, it is used to implement
2058the <tt>va_arg</tt> macro available in C. For more information, see
2059the variable argument handling <a href="#int_varargs">Intrinsic
2060Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2061
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2062<p>It is legal for this instruction to be called in a function which
2063does not take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2064function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2065
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2066<p><tt>vanext</tt> is an LLVM instruction instead of an <a
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2067href="#intrinsics">intrinsic function</a> because it takes a type as an
2068argument. The type refers to the current argument in the <tt>va_list</tt>, it
2069tells the compiler how far on the stack it needs to advance to find the next
2070argument</p>
2071
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2072<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2073
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2074<p>See the <a href="#int_varargs">variable argument processing</a>
2075section.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2076
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2077</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2078
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2079<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2080<div class="doc_subsubsection">
2081 <a name="i_vaarg">'<tt>vaarg</tt>' Instruction</a>
2082</div>
2083
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2084<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2085
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2086<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2087
2088<pre>
2089 &lt;resultval&gt; = vaarg &lt;va_list&gt; &lt;arglist&gt;, &lt;argty&gt;
2090</pre>
2091
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2092<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2093
2094<p>The '<tt>vaarg</tt>' instruction is used to access arguments passed through
2095the "variable argument" area of a function call. It is used to implement the
2096<tt>va_arg</tt> macro in C.</p>
2097
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2098<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2099
2100<p>This instruction takes a <tt>va_list</tt> value and the type of the
2101argument. It returns a value of the specified argument type. Again, the actual
2102type of <tt>va_list</tt> is target specific.</p>
2103
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2104<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2105
2106<p>The '<tt>vaarg</tt>' instruction loads an argument of the specified type from
2107the specified <tt>va_list</tt>. In conjunction with the <a
2108href="#i_vanext"><tt>vanext</tt></a> instruction, it is used to implement the
2109<tt>va_arg</tt> macro available in C. For more information, see the variable
2110argument handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
2111
2112<p>It is legal for this instruction to be called in a function which does not
2113take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2114function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2115
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2116<p><tt>vaarg</tt> is an LLVM instruction instead of an <a
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2117href="#intrinsics">intrinsic function</a> because it takes an type as an
2118argument.</p>
2119
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2120<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2121
2122<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
2123
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2124</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2125
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2126<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2127<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
2128<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2129
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2130<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2131
2132<p>LLVM supports the notion of an "intrinsic function". These functions have
2133well known names and semantics, and are required to follow certain
2134restrictions. Overall, these instructions represent an extension mechanism for
2135the LLVM language that does not require changing all of the transformations in
2136LLVM to add to the language (or the bytecode reader/writer, the parser,
2137etc...).</p>
2138
2139<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix, this
2140prefix is reserved in LLVM for intrinsic names, thus functions may not be named
2141this. Intrinsic functions must always be external functions: you cannot define
2142the body of intrinsic functions. Intrinsic functions may only be used in call
2143or invoke instructions: it is illegal to take the address of an intrinsic
2144function. Additionally, because intrinsic functions are part of the LLVM
2145language, it is required that they all be documented here if any are added.</p>
2146
2147
2148<p>
2149Adding an intrinsic to LLVM is straight-forward if it is possible to express the
2150concept in LLVM directly (ie, code generator support is not _required_). To do
2151this, extend the default implementation of the IntrinsicLowering class to handle
2152the intrinsic. Code generators use this class to lower intrinsics they do not
2153understand to raw LLVM instructions that they do.
2154</p>
2155
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2156</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2157
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2158<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2159<div class="doc_subsection">
2160 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
2161</div>
2162
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2163<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2164
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2165<p>Variable argument support is defined in LLVM with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2166 href="#i_vanext"><tt>vanext</tt></a> instruction and these three
2167intrinsic functions. These functions are related to the similarly
2168named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2169
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2170<p>All of these functions operate on arguments that use a
2171target-specific value type "<tt>va_list</tt>". The LLVM assembly
2172language reference manual does not define what this type is, so all
2173transformations should be prepared to handle intrinsics with any type
2174used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2175
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2176<p>This example shows how the <a href="#i_vanext"><tt>vanext</tt></a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2177instruction and the variable argument handling intrinsic functions are
2178used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2179
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2180<pre>
2181int %test(int %X, ...) {
2182 ; Initialize variable argument processing
2183 %ap = call sbyte* %<a href="#i_va_start">llvm.va_start</a>()
2184
2185 ; Read a single integer argument
2186 %tmp = vaarg sbyte* %ap, int
2187
2188 ; Advance to the next argument
2189 %ap2 = vanext sbyte* %ap, int
2190
2191 ; Demonstrate usage of llvm.va_copy and llvm.va_end
2192 %aq = call sbyte* %<a href="#i_va_copy">llvm.va_copy</a>(sbyte* %ap2)
2193 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %aq)
2194
2195 ; Stop processing of arguments.
2196 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %ap2)
2197 ret int %tmp
2198}
2199</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2200</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2201
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2202<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2203<div class="doc_subsubsection">
2204 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
2205</div>
2206
2207
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2208<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2209<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2210<pre> call &lt;va_list&gt; ()* %llvm.va_start()<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2211<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2212<p>The '<tt>llvm.va_start</tt>' intrinsic returns a new <tt>&lt;arglist&gt;</tt>
2213for subsequent use by the variable argument intrinsics.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2214<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2215<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]2216macro available in C. In a target-dependent way, it initializes and
2217returns a <tt>va_list</tt> element, so that the next <tt>vaarg</tt>
2218will produce the first variable argument passed to the function. Unlike
2219the C <tt>va_start</tt> macro, this intrinsic does not need to know the
2220last argument of the function, the compiler can figure that out.</p>
2221<p>Note that this intrinsic function is only legal to be called from
2222within the body of a variable argument function.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2223</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2224
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2225<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2226<div class="doc_subsubsection">
2227 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
2228</div>
2229
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2230<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2231<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2232<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]2233<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2234<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
2235which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
2236or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2237<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2238<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2239<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2240<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]2241macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
2242Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
2243 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
2244with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2245</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2246
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2247<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2248<div class="doc_subsubsection">
2249 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
2250</div>
2251
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2252<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2253
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2254<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2255
2256<pre>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2257 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]2258</pre>
2259
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2260<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2261
2262<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
2263from the source argument list to the destination argument list.</p>
2264
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2265<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2266
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2267<p>The argument is the <tt>va_list</tt> to copy.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2268
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2269<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2270
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2271<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]2272macro available in C. In a target-dependent way, it copies the source
2273<tt>va_list</tt> element into the returned list. This intrinsic is necessary
Chris Lattnerfcd37252004-06-21 22:52:48 +0000[diff] [blame]2274because 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]2275arbitrarily complex and require memory allocation, for example.</p>
2276
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2277</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2278
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2279<!-- ======================================================================= -->
2280<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2281 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
2282</div>
2283
2284<div class="doc_text">
2285
2286<p>
2287LLVM support for <a href="GarbageCollection.html">Accurate Garbage
2288Collection</a> requires the implementation and generation of these intrinsics.
2289These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
2290stack</a>, as well as garbage collector implementations that require <a
2291href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
2292Front-ends for type-safe garbage collected languages should generate these
2293intrinsics to make use of the LLVM garbage collectors. For more details, see <a
2294href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
2295</p>
2296</div>
2297
2298<!-- _______________________________________________________________________ -->
2299<div class="doc_subsubsection">
2300 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
2301</div>
2302
2303<div class="doc_text">
2304
2305<h5>Syntax:</h5>
2306
2307<pre>
2308 call void (&lt;ty&gt;**, &lt;ty2&gt;*)* %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
2309</pre>
2310
2311<h5>Overview:</h5>
2312
2313<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existance of a GC root to
2314the code generator, and allows some metadata to be associated with it.</p>
2315
2316<h5>Arguments:</h5>
2317
2318<p>The first argument specifies the address of a stack object that contains the
2319root pointer. The second pointer (which must be either a constant or a global
2320value address) contains the meta-data to be associated with the root.</p>
2321
2322<h5>Semantics:</h5>
2323
2324<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
2325location. At compile-time, the code generator generates information to allow
2326the runtime to find the pointer at GC safe points.
2327</p>
2328
2329</div>
2330
2331
2332<!-- _______________________________________________________________________ -->
2333<div class="doc_subsubsection">
2334 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
2335</div>
2336
2337<div class="doc_text">
2338
2339<h5>Syntax:</h5>
2340
2341<pre>
2342 call sbyte* (sbyte**)* %llvm.gcread(sbyte** %Ptr)
2343</pre>
2344
2345<h5>Overview:</h5>
2346
2347<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
2348locations, allowing garbage collector implementations that require read
2349barriers.</p>
2350
2351<h5>Arguments:</h5>
2352
2353<p>The argument is the address to read from, which should be an address
2354allocated from the garbage collector.</p>
2355
2356<h5>Semantics:</h5>
2357
2358<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
2359instruction, but may be replaced with substantially more complex code by the
2360garbage collector runtime, as needed.</p>
2361
2362</div>
2363
2364
2365<!-- _______________________________________________________________________ -->
2366<div class="doc_subsubsection">
2367 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
2368</div>
2369
2370<div class="doc_text">
2371
2372<h5>Syntax:</h5>
2373
2374<pre>
2375 call void (sbyte*, sbyte**)* %llvm.gcwrite(sbyte* %P1, sbyte** %P2)
2376</pre>
2377
2378<h5>Overview:</h5>
2379
2380<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
2381locations, allowing garbage collector implementations that require write
2382barriers (such as generational or reference counting collectors).</p>
2383
2384<h5>Arguments:</h5>
2385
2386<p>The first argument is the reference to store, and the second is the heap
2387location to store to.</p>
2388
2389<h5>Semantics:</h5>
2390
2391<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
2392instruction, but may be replaced with substantially more complex code by the
2393garbage collector runtime, as needed.</p>
2394
2395</div>
2396
2397
2398
2399<!-- ======================================================================= -->
2400<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2401 <a name="int_codegen">Code Generator Intrinsics</a>
2402</div>
2403
2404<div class="doc_text">
2405<p>
2406These intrinsics are provided by LLVM to expose special features that may only
2407be implemented with code generator support.
2408</p>
2409
2410</div>
2411
2412<!-- _______________________________________________________________________ -->
2413<div class="doc_subsubsection">
2414 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
2415</div>
2416
2417<div class="doc_text">
2418
2419<h5>Syntax:</h5>
2420<pre>
2421 call void* ()* %llvm.returnaddress(uint &lt;level&gt;)
2422</pre>
2423
2424<h5>Overview:</h5>
2425
2426<p>
2427The '<tt>llvm.returnaddress</tt>' intrinsic returns a target-specific value
2428indicating the return address of the current function or one of its callers.
2429</p>
2430
2431<h5>Arguments:</h5>
2432
2433<p>
2434The argument to this intrinsic indicates which function to return the address
2435for. Zero indicates the calling function, one indicates its caller, etc. The
2436argument is <b>required</b> to be a constant integer value.
2437</p>
2438
2439<h5>Semantics:</h5>
2440
2441<p>
2442The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
2443the return address of the specified call frame, or zero if it cannot be
2444identified. The value returned by this intrinsic is likely to be incorrect or 0
2445for arguments other than zero, so it should only be used for debugging purposes.
2446</p>
2447
2448<p>
2449Note that calling this intrinsic does not prevent function inlining or other
2450aggressive transformations, so the value returned may not that of the obvious
2451source-language caller.
2452</p>
2453</div>
2454
2455
2456<!-- _______________________________________________________________________ -->
2457<div class="doc_subsubsection">
2458 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
2459</div>
2460
2461<div class="doc_text">
2462
2463<h5>Syntax:</h5>
2464<pre>
2465 call void* ()* %llvm.frameaddress(uint &lt;level&gt;)
2466</pre>
2467
2468<h5>Overview:</h5>
2469
2470<p>
2471The '<tt>llvm.frameaddress</tt>' intrinsic returns the target-specific frame
2472pointer value for the specified stack frame.
2473</p>
2474
2475<h5>Arguments:</h5>
2476
2477<p>
2478The argument to this intrinsic indicates which function to return the frame
2479pointer for. Zero indicates the calling function, one indicates its caller,
2480etc. The argument is <b>required</b> to be a constant integer value.
2481</p>
2482
2483<h5>Semantics:</h5>
2484
2485<p>
2486The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
2487the frame address of the specified call frame, or zero if it cannot be
2488identified. The value returned by this intrinsic is likely to be incorrect or 0
2489for arguments other than zero, so it should only be used for debugging purposes.
2490</p>
2491
2492<p>
2493Note that calling this intrinsic does not prevent function inlining or other
2494aggressive transformations, so the value returned may not that of the obvious
2495source-language caller.
2496</p>
2497</div>
2498
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2499<!-- ======================================================================= -->
2500<div class="doc_subsection">
2501 <a name="int_os">Operating System Intrinsics</a>
2502</div>
2503
2504<div class="doc_text">
2505<p>
2506These intrinsics are provided by LLVM to support the implementation of
2507operating system level code.
2508</p>
2509
2510</div>
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2511
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2512<!-- _______________________________________________________________________ -->
2513<div class="doc_subsubsection">
2514 <a name="i_readport">'<tt>llvm.readport</tt>' Intrinsic</a>
2515</div>
2516
2517<div class="doc_text">
2518
2519<h5>Syntax:</h5>
2520<pre>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2521 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]2522</pre>
2523
2524<h5>Overview:</h5>
2525
2526<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2527The '<tt>llvm.readport</tt>' intrinsic reads data from the specified hardware
2528I/O port.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2529</p>
2530
2531<h5>Arguments:</h5>
2532
2533<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2534The argument to this intrinsic indicates the hardware I/O address from which
2535to read the data. The address is in the hardware I/O address namespace (as
2536opposed to being a memory location for memory mapped I/O).
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2537</p>
2538
2539<h5>Semantics:</h5>
2540
2541<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2542The '<tt>llvm.readport</tt>' intrinsic reads data from the hardware I/O port
2543specified by <i>address</i> and returns the value. The address and return
2544value must be integers, but the size is dependent upon the platform upon which
2545the program is code generated. For example, on x86, the address must be an
2546unsigned 16 bit value, and the return value must be 8, 16, or 32 bits.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2547</p>
2548
2549</div>
2550
2551<!-- _______________________________________________________________________ -->
2552<div class="doc_subsubsection">
2553 <a name="i_writeport">'<tt>llvm.writeport</tt>' Intrinsic</a>
2554</div>
2555
2556<div class="doc_text">
2557
2558<h5>Syntax:</h5>
2559<pre>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame^]2560 call void (&lt;integer type&gt;, &lt;integer type&gt;)*
2561 %llvm.writeport (&lt;integer type&gt; &lt;value&gt;,
2562 &lt;integer type&gt; &lt;address&gt;)
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2563</pre>
2564
2565<h5>Overview:</h5>
2566
2567<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2568The '<tt>llvm.writeport</tt>' intrinsic writes data to the specified hardware
2569I/O port.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2570</p>
2571
2572<h5>Arguments:</h5>
2573
2574<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2575The first argument is the value to write to the I/O port.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2576</p>
2577
2578<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2579The second argument indicates the hardware I/O address to which data should be
2580written. The address is in the hardware I/O address namespace (as opposed to
2581being a memory location for memory mapped I/O).
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2582</p>
2583
2584<h5>Semantics:</h5>
2585
2586<p>
2587The '<tt>llvm.writeport</tt>' intrinsic writes <i>value</i> to the I/O port
2588specified by <i>address</i>. The address and value must be integers, but the
2589size is dependent upon the platform upon which the program is code generated.
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2590For example, on x86, the address must be an unsigned 16 bit value, and the
2591value written must be 8, 16, or 32 bits in length.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2592</p>
2593
2594</div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2595
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2596<!-- _______________________________________________________________________ -->
2597<div class="doc_subsubsection">
2598 <a name="i_readio">'<tt>llvm.readio</tt>' Intrinsic</a>
2599</div>
2600
2601<div class="doc_text">
2602
2603<h5>Syntax:</h5>
2604<pre>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2605 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]2606</pre>
2607
2608<h5>Overview:</h5>
2609
2610<p>
2611The '<tt>llvm.readio</tt>' intrinsic reads data from a memory mapped I/O
2612address.
2613</p>
2614
2615<h5>Arguments:</h5>
2616
2617<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2618The argument to this intrinsic is a pointer indicating the memory address from
2619which to read the data. The data must be a
2620<a href="#t_firstclass">first class</a> type.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2621</p>
2622
2623<h5>Semantics:</h5>
2624
2625<p>
2626The '<tt>llvm.readio</tt>' intrinsic reads data from a memory mapped I/O
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2627location specified by <i>pointer</i> and returns the value. The argument must
2628be a pointer, and the return value must be a
2629<a href="#t_firstclass">first class</a> type. However, certain architectures
2630may not support I/O on all first class types. For example, 32 bit processors
2631may only support I/O on data types that are 32 bits or less.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2632</p>
2633
2634<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2635This intrinsic enforces an in-order memory model for llvm.readio and
2636llvm.writeio calls on machines that use dynamic scheduling. Dynamically
2637scheduled processors may execute loads and stores out of order, re-ordering at
2638run time accesses to memory mapped I/O registers. Using these intrinsics
2639ensures that accesses to memory mapped I/O registers occur in program order.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2640</p>
2641
2642</div>
2643
2644<!-- _______________________________________________________________________ -->
2645<div class="doc_subsubsection">
2646 <a name="i_writeio">'<tt>llvm.writeio</tt>' Intrinsic</a>
2647</div>
2648
2649<div class="doc_text">
2650
2651<h5>Syntax:</h5>
2652<pre>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2653 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]2654</pre>
2655
2656<h5>Overview:</h5>
2657
2658<p>
2659The '<tt>llvm.writeio</tt>' intrinsic writes data to the specified memory
2660mapped I/O address.
2661</p>
2662
2663<h5>Arguments:</h5>
2664
2665<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2666The first argument is the value to write to the memory mapped I/O location.
2667The second argument is a pointer indicating the memory address to which the
2668data should be written.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2669</p>
2670
2671<h5>Semantics:</h5>
2672
2673<p>
2674The '<tt>llvm.writeio</tt>' intrinsic writes <i>value</i> to the memory mapped
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2675I/O address specified by <i>pointer</i>. The value must be a
2676<a href="#t_firstclass">first class</a> type. However, certain architectures
2677may not support I/O on all first class types. For example, 32 bit processors
2678may only support I/O on data types that are 32 bits or less.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2679</p>
2680
2681<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2682This intrinsic enforces an in-order memory model for llvm.readio and
2683llvm.writeio calls on machines that use dynamic scheduling. Dynamically
2684scheduled processors may execute loads and stores out of order, re-ordering at
2685run time accesses to memory mapped I/O registers. Using these intrinsics
2686ensures that accesses to memory mapped I/O registers occur in program order.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2687</p>
2688
2689</div>
2690
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2691<!-- ======================================================================= -->
2692<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2693 <a name="int_libc">Standard C Library Intrinsics</a>
2694</div>
2695
2696<div class="doc_text">
2697<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2698LLVM provides intrinsics for a few important standard C library functions.
2699These intrinsics allow source-language front-ends to pass information about the
2700alignment of the pointer arguments to the code generator, providing opportunity
2701for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2702</p>
2703
2704</div>
2705
2706<!-- _______________________________________________________________________ -->
2707<div class="doc_subsubsection">
2708 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
2709</div>
2710
2711<div class="doc_text">
2712
2713<h5>Syntax:</h5>
2714<pre>
2715 call void (sbyte*, sbyte*, uint, uint)* %llvm.memcpy(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
2716 uint &lt;len&gt;, uint &lt;align&gt;)
2717</pre>
2718
2719<h5>Overview:</h5>
2720
2721<p>
2722The '<tt>llvm.memcpy</tt>' intrinsic copies a block of memory from the source
2723location to the destination location.
2724</p>
2725
2726<p>
2727Note that, unlike the standard libc function, the <tt>llvm.memcpy</tt> intrinsic
2728does not return a value, and takes an extra alignment argument.
2729</p>
2730
2731<h5>Arguments:</h5>
2732
2733<p>
2734The first argument is a pointer to the destination, the second is a pointer to
2735the source. The third argument is an (arbitrarily sized) integer argument
2736specifying the number of bytes to copy, and the fourth argument is the alignment
2737of the source and destination locations.
2738</p>
2739
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]2740<p>
2741If the call to this intrinisic has an alignment value that is not 0 or 1, then
2742the caller guarantees that the size of the copy is a multiple of the alignment
2743and that both the source and destination pointers are aligned to that boundary.
2744</p>
2745
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2746<h5>Semantics:</h5>
2747
2748<p>
2749The '<tt>llvm.memcpy</tt>' intrinsic copies a block of memory from the source
2750location to the destination location, which are not allowed to overlap. It
2751copies "len" bytes of memory over. If the argument is known to be aligned to
2752some boundary, this can be specified as the fourth argument, otherwise it should
2753be set to 0 or 1.
2754</p>
2755</div>
2756
2757
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]2758<!-- _______________________________________________________________________ -->
2759<div class="doc_subsubsection">
2760 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
2761</div>
2762
2763<div class="doc_text">
2764
2765<h5>Syntax:</h5>
2766<pre>
2767 call void (sbyte*, sbyte*, uint, uint)* %llvm.memmove(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
2768 uint &lt;len&gt;, uint &lt;align&gt;)
2769</pre>
2770
2771<h5>Overview:</h5>
2772
2773<p>
2774The '<tt>llvm.memmove</tt>' intrinsic moves a block of memory from the source
2775location to the destination location. It is similar to the '<tt>llvm.memcpy</tt>'
2776intrinsic but allows the two memory locations to overlap.
2777</p>
2778
2779<p>
2780Note that, unlike the standard libc function, the <tt>llvm.memmove</tt> intrinsic
2781does not return a value, and takes an extra alignment argument.
2782</p>
2783
2784<h5>Arguments:</h5>
2785
2786<p>
2787The first argument is a pointer to the destination, the second is a pointer to
2788the source. The third argument is an (arbitrarily sized) integer argument
2789specifying the number of bytes to copy, and the fourth argument is the alignment
2790of the source and destination locations.
2791</p>
2792
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]2793<p>
2794If the call to this intrinisic has an alignment value that is not 0 or 1, then
2795the caller guarantees that the size of the copy is a multiple of the alignment
2796and that both the source and destination pointers are aligned to that boundary.
2797</p>
2798
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]2799<h5>Semantics:</h5>
2800
2801<p>
2802The '<tt>llvm.memmove</tt>' intrinsic copies a block of memory from the source
2803location to the destination location, which may overlap. It
2804copies "len" bytes of memory over. If the argument is known to be aligned to
2805some boundary, this can be specified as the fourth argument, otherwise it should
2806be set to 0 or 1.
2807</p>
2808</div>
2809
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2810
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2811<!-- _______________________________________________________________________ -->
2812<div class="doc_subsubsection">
2813 <a name="i_memset">'<tt>llvm.memset</tt>' Intrinsic</a>
2814</div>
2815
2816<div class="doc_text">
2817
2818<h5>Syntax:</h5>
2819<pre>
2820 call void (sbyte*, ubyte, uint, uint)* %llvm.memset(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
2821 uint &lt;len&gt;, uint &lt;align&gt;)
2822</pre>
2823
2824<h5>Overview:</h5>
2825
2826<p>
2827The '<tt>llvm.memset</tt>' intrinsic fills a block of memory with a particular
2828byte value.
2829</p>
2830
2831<p>
2832Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
2833does not return a value, and takes an extra alignment argument.
2834</p>
2835
2836<h5>Arguments:</h5>
2837
2838<p>
2839The first argument is a pointer to the destination to fill, the second is the
2840byte value to fill it with, the third argument is an (arbitrarily sized) integer
2841argument specifying the number of bytes to fill, and the fourth argument is the
2842known alignment of destination location.
2843</p>
2844
2845<p>
2846If the call to this intrinisic has an alignment value that is not 0 or 1, then
2847the caller guarantees that the size of the copy is a multiple of the alignment
2848and that the destination pointer is aligned to that boundary.
2849</p>
2850
2851<h5>Semantics:</h5>
2852
2853<p>
2854The '<tt>llvm.memset</tt>' intrinsic fills "len" bytes of memory starting at the
2855destination location. If the argument is known to be aligned to some boundary,
2856this can be specified as the fourth argument, otherwise it should be set to 0 or
28571.
2858</p>
2859</div>
2860
2861
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]2862<!-- _______________________________________________________________________ -->
2863<div class="doc_subsubsection">
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]2864 <a name="i_isunordered">'<tt>llvm.isunordered</tt>' Intrinsic</a>
2865</div>
2866
2867<div class="doc_text">
2868
2869<h5>Syntax:</h5>
2870<pre>
2871 call bool (&lt;float or double&gt;, &lt;float or double&gt;)* %llvm.isunordered(&lt;float or double&gt; Val1,
2872 &lt;float or double&gt; Val2)
2873</pre>
2874
2875<h5>Overview:</h5>
2876
2877<p>
2878The '<tt>llvm.isunordered</tt>' intrinsic returns true if either or both of the
2879specified floating point values is a NAN.
2880</p>
2881
2882<h5>Arguments:</h5>
2883
2884<p>
2885The arguments are floating point numbers of the same type.
2886</p>
2887
2888<h5>Semantics:</h5>
2889
2890<p>
2891If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
2892false.
2893</p>
2894</div>
2895
2896
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]2897
2898
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2899<!-- ======================================================================= -->
2900<div class="doc_subsection">
2901 <a name="int_debugger">Debugger Intrinsics</a>
2902</div>
2903
2904<div class="doc_text">
2905<p>
2906The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
2907are described in the <a
2908href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
2909Debugging</a> document.
2910</p>
2911</div>
2912
2913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2914<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2915<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2916<address>
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2921
2922 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
2923 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
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