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gerrit-public.fairphone.software / toolchain / llvm-project / 5305ea5c86345414a14db97d9dfc8775dfc80e1f / . / llvm / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
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11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 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 Lattner6af02f32004-12-09 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 Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
26 <li><a href="#functionstructure">Function Structure</a></li>
27 </ol>
28 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]29 <li><a href="#typesystem">Type System</a>
30 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]31 <li><a href="#t_primitive">Primitive Types</a>
32 <ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]33 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]34 </ol>
35 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]36 <li><a href="#t_derived">Derived Types</a>
37 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]38 <li><a href="#t_array">Array Type</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]39 <li><a href="#t_function">Function Type</a></li>
40 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]41 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]42 <li><a href="#t_packed">Packed Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]43 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]44 </ol>
45 </li>
46 </ol>
47 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]48 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]49 <ol>
50 <li><a href="#simpleconstants">Simple Constants</a>
51 <li><a href="#aggregateconstants">Aggregate Constants</a>
52 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
53 <li><a href="#undefvalues">Undefined Values</a>
54 <li><a href="#constantexprs">Constant Expressions</a>
55 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]56 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]57 <li><a href="#instref">Instruction Reference</a>
58 <ol>
59 <li><a href="#terminators">Terminator Instructions</a>
60 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]61 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
62 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]63 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
64 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]65 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]66 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]67 </ol>
68 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]69 <li><a href="#binaryops">Binary Operations</a>
70 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
72 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
73 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
74 <li><a href="#i_div">'<tt>div</tt>' Instruction</a></li>
75 <li><a href="#i_rem">'<tt>rem</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]76 <li><a href="#i_setcc">'<tt>set<i>cc</i></tt>' Instructions</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]77 </ol>
78 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]79 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
80 <ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]81 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]82 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]83 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
84 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
85 <li><a href="#i_shr">'<tt>shr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]86 </ol>
87 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]88 <li><a href="#memoryops">Memory Access Operations</a>
89 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]90 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
91 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
92 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
93 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
94 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
95 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
96 </ol>
97 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]98 <li><a href="#otherops">Other Operations</a>
99 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]100 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]101 <li><a href="#i_cast">'<tt>cast .. to</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]102 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]103 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]104 <li><a href="#i_vaarg">'<tt>vaarg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]105 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]106 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]107 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]108 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]109 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]110 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]111 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
112 <ol>
113 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
114 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
115 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
116 </ol>
117 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]118 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
119 <ol>
120 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
121 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
122 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
123 </ol>
124 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]125 <li><a href="#int_codegen">Code Generator Intrinsics</a>
126 <ol>
127 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
128 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]129 <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]130 <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]131 </ol>
132 </li>
133 <li><a href="#int_os">Operating System Intrinsics</a>
134 <ol>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]135 <li><a href="#i_readport">'<tt>llvm.readport</tt>' Intrinsic</a></li>
136 <li><a href="#i_writeport">'<tt>llvm.writeport</tt>' Intrinsic</a></li>
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]137 <li><a href="#i_readio">'<tt>llvm.readio</tt>' Intrinsic</a></li>
138 <li><a href="#i_writeio">'<tt>llvm.writeio</tt>' Intrinsic</a></li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]139 </ol>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]140 <li><a href="#int_libc">Standard C Library Intrinsics</a>
141 <ol>
142 <li><a href="#i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a></li>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]143 <li><a href="#i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a></li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]144 <li><a href="#i_memset">'<tt>llvm.memset</tt>' Intrinsic</a></li>
Alkis Evlogimenos9d740622004-06-12 19:19:14 +0000[diff] [blame]145 <li><a href="#i_isunordered">'<tt>llvm.isunordered</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]146 </ol>
147 </li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]148 <li><a href="#int_count">Bit counting Intrinsics</a>
149 <ol>
150 <li><a href="#int_ctpop">'<tt>llvm.ctpop</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]151 <li><a href="#int_ctlz">'<tt>llvm.ctlz</tt>' Intrinsic </a></li>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]152 <li><a href="#int_cttz">'<tt>llvm.cttz</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]153 </ol>
154 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]155 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]156 </ol>
157 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]158</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]159
160<div class="doc_author">
161 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
162 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]163</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]164
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]165<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]166<div class="doc_section"> <a name="abstract">Abstract </a></div>
167<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]168
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]169<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]170<p>This document is a reference manual for the LLVM assembly language.
171LLVM is an SSA based representation that provides type safety,
172low-level operations, flexibility, and the capability of representing
173'all' high-level languages cleanly. It is the common code
174representation used throughout all phases of the LLVM compilation
175strategy.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]176</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]177
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]178<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]179<div class="doc_section"> <a name="introduction">Introduction</a> </div>
180<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]181
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]182<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]183
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]184<p>The LLVM code representation is designed to be used in three
185different forms: as an in-memory compiler IR, as an on-disk bytecode
186representation (suitable for fast loading by a Just-In-Time compiler),
187and as a human readable assembly language representation. This allows
188LLVM to provide a powerful intermediate representation for efficient
189compiler transformations and analysis, while providing a natural means
190to debug and visualize the transformations. The three different forms
191of LLVM are all equivalent. This document describes the human readable
192representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]193
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]194<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]195while being expressive, typed, and extensible at the same time. It
196aims to be a "universal IR" of sorts, by being at a low enough level
197that high-level ideas may be cleanly mapped to it (similar to how
198microprocessors are "universal IR's", allowing many source languages to
199be mapped to them). By providing type information, LLVM can be used as
200the target of optimizations: for example, through pointer analysis, it
201can be proven that a C automatic variable is never accessed outside of
202the current function... allowing it to be promoted to a simple SSA
203value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]204
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]205</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]206
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]207<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]208<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]209
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]210<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]211
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]212<p>It is important to note that this document describes 'well formed'
213LLVM assembly language. There is a difference between what the parser
214accepts and what is considered 'well formed'. For example, the
215following instruction is syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]216
217<pre>
218 %x = <a href="#i_add">add</a> int 1, %x
219</pre>
220
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]221<p>...because the definition of <tt>%x</tt> does not dominate all of
222its uses. The LLVM infrastructure provides a verification pass that may
223be used to verify that an LLVM module is well formed. This pass is
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]224automatically run by the parser after parsing input assembly and by
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]225the optimizer before it outputs bytecode. The violations pointed out
226by the verifier pass indicate bugs in transformation passes or input to
227the parser.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]228
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]229<!-- Describe the typesetting conventions here. --> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]230
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]231<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]232<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]233<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]234
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]235<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]236
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]237<p>LLVM uses three different forms of identifiers, for different
238purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]239
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]240<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]241 <li>Named values are represented as a string of characters with a '%' prefix.
242 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
243 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
244 Identifiers which require other characters in their names can be surrounded
245 with quotes. In this way, anything except a <tt>"</tt> character can be used
246 in a name.</li>
247
248 <li>Unnamed values are represented as an unsigned numeric value with a '%'
249 prefix. For example, %12, %2, %44.</li>
250
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]251 <li>Constants, which are described in a <a href="#constants">section about
252 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]253</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]254
255<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
256don't need to worry about name clashes with reserved words, and the set of
257reserved words may be expanded in the future without penalty. Additionally,
258unnamed identifiers allow a compiler to quickly come up with a temporary
259variable without having to avoid symbol table conflicts.</p>
260
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]261<p>Reserved words in LLVM are very similar to reserved words in other
262languages. There are keywords for different opcodes ('<tt><a
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]263href="#i_add">add</a></tt>', '<tt><a href="#i_cast">cast</a></tt>', '<tt><a
264href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
265href="#t_void">void</a></tt>', '<tt><a href="#t_uint">uint</a></tt>', etc...),
266and others. These reserved words cannot conflict with variable names, because
267none of them start with a '%' character.</p>
268
269<p>Here is an example of LLVM code to multiply the integer variable
270'<tt>%X</tt>' by 8:</p>
271
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]272<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]273
274<pre>
275 %result = <a href="#i_mul">mul</a> uint %X, 8
276</pre>
277
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]278<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]279
280<pre>
281 %result = <a href="#i_shl">shl</a> uint %X, ubyte 3
282</pre>
283
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]284<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]285
286<pre>
287 <a href="#i_add">add</a> uint %X, %X <i>; yields {uint}:%0</i>
288 <a href="#i_add">add</a> uint %0, %0 <i>; yields {uint}:%1</i>
289 %result = <a href="#i_add">add</a> uint %1, %1
290</pre>
291
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]292<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
293important lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]294
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]295<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]296
297 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
298 line.</li>
299
300 <li>Unnamed temporaries are created when the result of a computation is not
301 assigned to a named value.</li>
302
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]303 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]304
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]305</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]306
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]307<p>...and it also shows a convention that we follow in this document. When
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]308demonstrating instructions, we will follow an instruction with a comment that
309defines the type and name of value produced. Comments are shown in italic
310text.</p>
311
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]312</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]313
314<!-- *********************************************************************** -->
315<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
316<!-- *********************************************************************** -->
317
318<!-- ======================================================================= -->
319<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
320</div>
321
322<div class="doc_text">
323
324<p>LLVM programs are composed of "Module"s, each of which is a
325translation unit of the input programs. Each module consists of
326functions, global variables, and symbol table entries. Modules may be
327combined together with the LLVM linker, which merges function (and
328global variable) definitions, resolves forward declarations, and merges
329symbol table entries. Here is an example of the "hello world" module:</p>
330
331<pre><i>; Declare the string constant as a global constant...</i>
332<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
333 href="#globalvars">constant</a> <a href="#t_array">[13 x sbyte]</a> c"hello world\0A\00" <i>; [13 x sbyte]*</i>
334
335<i>; External declaration of the puts function</i>
336<a href="#functionstructure">declare</a> int %puts(sbyte*) <i>; int(sbyte*)* </i>
337
338<i>; Definition of main function</i>
339int %main() { <i>; int()* </i>
340 <i>; Convert [13x sbyte]* to sbyte *...</i>
341 %cast210 = <a
342 href="#i_getelementptr">getelementptr</a> [13 x sbyte]* %.LC0, long 0, long 0 <i>; sbyte*</i>
343
344 <i>; Call puts function to write out the string to stdout...</i>
345 <a
346 href="#i_call">call</a> int %puts(sbyte* %cast210) <i>; int</i>
347 <a
348 href="#i_ret">ret</a> int 0<br>}<br></pre>
349
350<p>This example is made up of a <a href="#globalvars">global variable</a>
351named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
352function, and a <a href="#functionstructure">function definition</a>
353for "<tt>main</tt>".</p>
354
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]355<p>In general, a module is made up of a list of global values,
356where both functions and global variables are global values. Global values are
357represented by a pointer to a memory location (in this case, a pointer to an
358array of char, and a pointer to a function), and have one of the following <a
359href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]360
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]361</div>
362
363<!-- ======================================================================= -->
364<div class="doc_subsection">
365 <a name="linkage">Linkage Types</a>
366</div>
367
368<div class="doc_text">
369
370<p>
371All Global Variables and Functions have one of the following types of linkage:
372</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]373
374<dl>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]375
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]376 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]377
378 <dd>Global values with internal linkage are only directly accessible by
379 objects in the current module. In particular, linking code into a module with
380 an internal global value may cause the internal to be renamed as necessary to
381 avoid collisions. Because the symbol is internal to the module, all
382 references can be updated. This corresponds to the notion of the
383 '<tt>static</tt>' keyword in C, or the idea of "anonymous namespaces" in C++.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]384 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]385
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]386 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]387
388 <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with
389 the twist that linking together two modules defining the same
390 <tt>linkonce</tt> globals will cause one of the globals to be discarded. This
391 is typically used to implement inline functions. Unreferenced
392 <tt>linkonce</tt> globals are allowed to be discarded.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]393 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]394
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]395 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]396
397 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
398 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
399 used to implement constructs in C such as "<tt>int X;</tt>" at global scope.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]400 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]401
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]402 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]403
404 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
405 pointer to array type. When two global variables with appending linkage are
406 linked together, the two global arrays are appended together. This is the
407 LLVM, typesafe, equivalent of having the system linker append together
408 "sections" with identical names when .o files are linked.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]409 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]410
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]411 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]412
413 <dd>If none of the above identifiers are used, the global is externally
414 visible, meaning that it participates in linkage and can be used to resolve
415 external symbol references.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]416 </dd>
417</dl>
418
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]419<p><a name="linkage_external">For example, since the "<tt>.LC0</tt>"
420variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
421variable and was linked with this one, one of the two would be renamed,
422preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
423external (i.e., lacking any linkage declarations), they are accessible
424outside of the current module. It is illegal for a function <i>declaration</i>
425to have any linkage type other than "externally visible".</a></p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]426
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]427</div>
428
429<!-- ======================================================================= -->
430<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]431 <a name="callingconv">Calling Conventions</a>
432</div>
433
434<div class="doc_text">
435
436<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
437and <a href="#i_invoke">invokes</a> can all have an optional calling convention
438specified for the call. The calling convention of any pair of dynamic
439caller/callee must match, or the behavior of the program is undefined. The
440following calling conventions are supported by LLVM, and more may be added in
441the future:</p>
442
443<dl>
444 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
445
446 <dd>This calling convention (the default if no other calling convention is
447 specified) matches the target C calling conventions. This calling convention
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]448 supports varargs function calls and tolerates some mismatch in the declared
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]449 prototype and implemented declaration of the function (as does normal C).
450 </dd>
451
452 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
453
454 <dd>This calling convention attempts to make calls as fast as possible
455 (e.g. by passing things in registers). This calling convention allows the
456 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattnerc792eb32005-05-06 23:08:23 +0000[diff] [blame]457 without having to conform to an externally specified ABI. Implementations of
458 this convention should allow arbitrary tail call optimization to be supported.
459 This calling convention does not support varargs and requires the prototype of
460 all callees to exactly match the prototype of the function definition.
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]461 </dd>
462
463 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
464
465 <dd>This calling convention attempts to make code in the caller as efficient
466 as possible under the assumption that the call is not commonly executed. As
467 such, these calls often preserve all registers so that the call does not break
468 any live ranges in the caller side. This calling convention does not support
469 varargs and requires the prototype of all callees to exactly match the
470 prototype of the function definition.
471 </dd>
472
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]473 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]474
475 <dd>Any calling convention may be specified by number, allowing
476 target-specific calling conventions to be used. Target specific calling
477 conventions start at 64.
478 </dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]479</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]480
481<p>More calling conventions can be added/defined on an as-needed basis, to
482support pascal conventions or any other well-known target-independent
483convention.</p>
484
485</div>
486
487<!-- ======================================================================= -->
488<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]489 <a name="globalvars">Global Variables</a>
490</div>
491
492<div class="doc_text">
493
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]494<p>Global variables define regions of memory allocated at compilation time
495instead of run-time. Global variables may optionally be initialized. A
496variable may be defined as a global "constant", which indicates that the
497contents of the variable will <b>never</b> be modified (enabling better
498optimization, allowing the global data to be placed in the read-only section of
499an executable, etc). Note that variables that need runtime initialization
500cannot be marked "constant", as there is a store to the variable.</p>
501
502<p>
503LLVM explicitly allows <em>declarations</em> of global variables to be marked
504constant, even if the final definition of the global is not. This capability
505can be used to enable slightly better optimization of the program, but requires
506the language definition to guarantee that optimizations based on the
507'constantness' are valid for the translation units that do not include the
508definition.
509</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]510
511<p>As SSA values, global variables define pointer values that are in
512scope (i.e. they dominate) all basic blocks in the program. Global
513variables always define a pointer to their "content" type because they
514describe a region of memory, and all memory objects in LLVM are
515accessed through pointers.</p>
516
517</div>
518
519
520<!-- ======================================================================= -->
521<div class="doc_subsection">
522 <a name="functionstructure">Functions</a>
523</div>
524
525<div class="doc_text">
526
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]527<p>LLVM function definitions consist of an optional <a href="#linkage">linkage
528type</a>, an optional <a href="#callingconv">calling convention</a>, a return
529type, a function name, a (possibly empty) argument list, an opening curly brace,
530a list of basic blocks, and a closing curly brace. LLVM function declarations
531are defined with the "<tt>declare</tt>" keyword, an optional <a
532href="#callingconv">calling convention</a>, a return type, a function name, and
533a possibly empty list of arguments.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]534
535<p>A function definition contains a list of basic blocks, forming the CFG for
536the function. Each basic block may optionally start with a label (giving the
537basic block a symbol table entry), contains a list of instructions, and ends
538with a <a href="#terminators">terminator</a> instruction (such as a branch or
539function return).</p>
540
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]541<p>The first basic block in a program is special in two ways: it is immediately
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]542executed on entrance to the function, and it is not allowed to have predecessor
543basic blocks (i.e. there can not be any branches to the entry block of a
544function). Because the block can have no predecessors, it also cannot have any
545<a href="#i_phi">PHI nodes</a>.</p>
546
547<p>LLVM functions are identified by their name and type signature. Hence, two
548functions with the same name but different parameter lists or return values are
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]549considered different functions, and LLVM will resolve references to each
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]550appropriately.</p>
551
552</div>
553
554
555
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]556<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]557<div class="doc_section"> <a name="typesystem">Type System</a> </div>
558<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]559
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]560<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]561
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]562<p>The LLVM type system is one of the most important features of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]563intermediate representation. Being typed enables a number of
564optimizations to be performed on the IR directly, without having to do
565extra analyses on the side before the transformation. A strong type
566system makes it easier to read the generated code and enables novel
567analyses and transformations that are not feasible to perform on normal
568three address code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]569
570</div>
571
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]572<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]573<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]574<div class="doc_text">
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]575<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]576system. The current set of primitive types is as follows:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]577
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]578<table class="layout">
579 <tr class="layout">
580 <td class="left">
581 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]582 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]583 <tr><th>Type</th><th>Description</th></tr>
584 <tr><td><tt>void</tt></td><td>No value</td></tr>
Misha Brukman36c6bc12005-04-22 18:02:52 +0000[diff] [blame]585 <tr><td><tt>ubyte</tt></td><td>Unsigned 8-bit value</td></tr>
586 <tr><td><tt>ushort</tt></td><td>Unsigned 16-bit value</td></tr>
587 <tr><td><tt>uint</tt></td><td>Unsigned 32-bit value</td></tr>
588 <tr><td><tt>ulong</tt></td><td>Unsigned 64-bit value</td></tr>
589 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]590 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]591 </tbody>
592 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]593 </td>
594 <td class="right">
595 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]596 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]597 <tr><th>Type</th><th>Description</th></tr>
598 <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
Misha Brukman36c6bc12005-04-22 18:02:52 +0000[diff] [blame]599 <tr><td><tt>sbyte</tt></td><td>Signed 8-bit value</td></tr>
600 <tr><td><tt>short</tt></td><td>Signed 16-bit value</td></tr>
601 <tr><td><tt>int</tt></td><td>Signed 32-bit value</td></tr>
602 <tr><td><tt>long</tt></td><td>Signed 64-bit value</td></tr>
603 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]604 </tbody>
605 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]606 </td>
607 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]608</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]609</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]610
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]611<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]612<div class="doc_subsubsection"> <a name="t_classifications">Type
613Classifications</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]614<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]615<p>These different primitive types fall into a few useful
616classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]617
618<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]619 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]620 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]621 <tr>
622 <td><a name="t_signed">signed</a></td>
623 <td><tt>sbyte, short, int, long, float, double</tt></td>
624 </tr>
625 <tr>
626 <td><a name="t_unsigned">unsigned</a></td>
627 <td><tt>ubyte, ushort, uint, ulong</tt></td>
628 </tr>
629 <tr>
630 <td><a name="t_integer">integer</a></td>
631 <td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td>
632 </tr>
633 <tr>
634 <td><a name="t_integral">integral</a></td>
Misha Brukman20f9a622004-08-12 20:16:08 +0000[diff] [blame]635 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long</tt>
636 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]637 </tr>
638 <tr>
639 <td><a name="t_floating">floating point</a></td>
640 <td><tt>float, double</tt></td>
641 </tr>
642 <tr>
643 <td><a name="t_firstclass">first class</a></td>
Misha Brukman20f9a622004-08-12 20:16:08 +0000[diff] [blame]644 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long,<br>
645 float, double, <a href="#t_pointer">pointer</a>,
646 <a href="#t_packed">packed</a></tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]647 </tr>
648 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]649</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]650
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]651<p>The <a href="#t_firstclass">first class</a> types are perhaps the
652most important. Values of these types are the only ones which can be
653produced by instructions, passed as arguments, or used as operands to
654instructions. This means that all structures and arrays must be
655manipulated either by pointer or by component.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]656</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]657
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]658<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]659<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]660
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]661<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]662
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]663<p>The real power in LLVM comes from the derived types in the system.
664This is what allows a programmer to represent arrays, functions,
665pointers, and other useful types. Note that these derived types may be
666recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]667
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]668</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]669
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]670<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]671<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]672
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]673<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]674
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]675<h5>Overview:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]676
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]677<p>The array type is a very simple derived type that arranges elements
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]678sequentially in memory. The array type requires a size (number of
679elements) and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]680
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]681<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]682
683<pre>
684 [&lt;# elements&gt; x &lt;elementtype&gt;]
685</pre>
686
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]687<p>The number of elements is a constant integer value; elementtype may
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]688be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]689
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]690<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]691<table class="layout">
692 <tr class="layout">
693 <td class="left">
694 <tt>[40 x int ]</tt><br/>
695 <tt>[41 x int ]</tt><br/>
696 <tt>[40 x uint]</tt><br/>
697 </td>
698 <td class="left">
699 Array of 40 integer values.<br/>
700 Array of 41 integer values.<br/>
701 Array of 40 unsigned integer values.<br/>
702 </td>
703 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]704</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]705<p>Here are some examples of multidimensional arrays:</p>
706<table class="layout">
707 <tr class="layout">
708 <td class="left">
709 <tt>[3 x [4 x int]]</tt><br/>
710 <tt>[12 x [10 x float]]</tt><br/>
711 <tt>[2 x [3 x [4 x uint]]]</tt><br/>
712 </td>
713 <td class="left">
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]714 3x4 array of integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]715 12x10 array of single precision floating point values.<br/>
716 2x3x4 array of unsigned integer values.<br/>
717 </td>
718 </tr>
719</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]720</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]721
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]722<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]723<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]724<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]725<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]726<p>The function type can be thought of as a function signature. It
727consists of a return type and a list of formal parameter types.
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]728Function types are usually used to build virtual function tables
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]729(which are structures of pointers to functions), for indirect function
730calls, and when defining a function.</p>
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]731<p>
732The return type of a function type cannot be an aggregate type.
733</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]734<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]735<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
Misha Brukman20f9a622004-08-12 20:16:08 +0000[diff] [blame]736<p>Where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
737specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]738which indicates that the function takes a variable number of arguments.
739Variable argument functions can access their arguments with the <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]740 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]741<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]742<table class="layout">
743 <tr class="layout">
744 <td class="left">
745 <tt>int (int)</tt> <br/>
746 <tt>float (int, int *) *</tt><br/>
747 <tt>int (sbyte *, ...)</tt><br/>
748 </td>
749 <td class="left">
750 function taking an <tt>int</tt>, returning an <tt>int</tt><br/>
751 <a href="#t_pointer">Pointer</a> to a function that takes an
Misha Brukman20f9a622004-08-12 20:16:08 +0000[diff] [blame]752 <tt>int</tt> and a <a href="#t_pointer">pointer</a> to <tt>int</tt>,
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]753 returning <tt>float</tt>.<br/>
754 A vararg function that takes at least one <a href="#t_pointer">pointer</a>
755 to <tt>sbyte</tt> (signed char in C), which returns an integer. This is
756 the signature for <tt>printf</tt> in LLVM.<br/>
757 </td>
758 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]759</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]760
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]761</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]762<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]763<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]764<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]765<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]766<p>The structure type is used to represent a collection of data members
767together in memory. The packing of the field types is defined to match
768the ABI of the underlying processor. The elements of a structure may
769be any type that has a size.</p>
770<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
771and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
772field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
773instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]774<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]775<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]776<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]777<table class="layout">
778 <tr class="layout">
779 <td class="left">
780 <tt>{ int, int, int }</tt><br/>
781 <tt>{ float, int (int) * }</tt><br/>
782 </td>
783 <td class="left">
784 a triple of three <tt>int</tt> values<br/>
785 A pair, where the first element is a <tt>float</tt> and the second element
786 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
787 that takes an <tt>int</tt>, returning an <tt>int</tt>.<br/>
788 </td>
789 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]790</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]791</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]792
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]793<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]794<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]795<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]796<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]797<p>As in many languages, the pointer type represents a pointer or
798reference to another object, which must live in memory.</p>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]799<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]800<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]801<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]802<table class="layout">
803 <tr class="layout">
804 <td class="left">
805 <tt>[4x int]*</tt><br/>
806 <tt>int (int *) *</tt><br/>
807 </td>
808 <td class="left">
809 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
810 four <tt>int</tt> values<br/>
811 A <a href="#t_pointer">pointer</a> to a <a
Chris Lattner16fb0032005-02-19 02:22:14 +0000[diff] [blame]812 href="#t_function">function</a> that takes an <tt>int*</tt>, returning an
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]813 <tt>int</tt>.<br/>
814 </td>
815 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]816</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]817</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]818
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]819<!-- _______________________________________________________________________ -->
820<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]821<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]822
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]823<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]824
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]825<p>A packed type is a simple derived type that represents a vector
826of elements. Packed types are used when multiple primitive data
827are operated in parallel using a single instruction (SIMD).
828A packed type requires a size (number of
829elements) and an underlying primitive data type. Packed types are
830considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]831
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]832<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]833
834<pre>
835 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
836</pre>
837
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]838<p>The number of elements is a constant integer value; elementtype may
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]839be any integral or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]840
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]841<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]842
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]843<table class="layout">
844 <tr class="layout">
845 <td class="left">
846 <tt>&lt;4 x int&gt;</tt><br/>
847 <tt>&lt;8 x float&gt;</tt><br/>
848 <tt>&lt;2 x uint&gt;</tt><br/>
849 </td>
850 <td class="left">
851 Packed vector of 4 integer values.<br/>
852 Packed vector of 8 floating-point values.<br/>
853 Packed vector of 2 unsigned integer values.<br/>
854 </td>
855 </tr>
856</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]857</div>
858
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]859<!-- _______________________________________________________________________ -->
860<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
861<div class="doc_text">
862
863<h5>Overview:</h5>
864
865<p>Opaque types are used to represent unknown types in the system. This
866corresponds (for example) to the C notion of a foward declared structure type.
867In LLVM, opaque types can eventually be resolved to any type (not just a
868structure type).</p>
869
870<h5>Syntax:</h5>
871
872<pre>
873 opaque
874</pre>
875
876<h5>Examples:</h5>
877
878<table class="layout">
879 <tr class="layout">
880 <td class="left">
881 <tt>opaque</tt>
882 </td>
883 <td class="left">
884 An opaque type.<br/>
885 </td>
886 </tr>
887</table>
888</div>
889
890
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]891<!-- *********************************************************************** -->
892<div class="doc_section"> <a name="constants">Constants</a> </div>
893<!-- *********************************************************************** -->
894
895<div class="doc_text">
896
897<p>LLVM has several different basic types of constants. This section describes
898them all and their syntax.</p>
899
900</div>
901
902<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]903<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]904
905<div class="doc_text">
906
907<dl>
908 <dt><b>Boolean constants</b></dt>
909
910 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
911 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
912 </dd>
913
914 <dt><b>Integer constants</b></dt>
915
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]916 <dd>Standard integers (such as '4') are constants of the <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]917 href="#t_integer">integer</a> type. Negative numbers may be used with signed
918 integer types.
919 </dd>
920
921 <dt><b>Floating point constants</b></dt>
922
923 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
924 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]925 notation (see below). Floating point constants must have a <a
926 href="#t_floating">floating point</a> type. </dd>
927
928 <dt><b>Null pointer constants</b></dt>
929
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]930 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]931 and must be of <a href="#t_pointer">pointer type</a>.</dd>
932
933</dl>
934
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]935<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]936of floating point constants. For example, the form '<tt>double
9370x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
9384.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]939(and the only time that they are generated by the disassembler) is when a
940floating point constant must be emitted but it cannot be represented as a
941decimal floating point number. For example, NaN's, infinities, and other
942special values are represented in their IEEE hexadecimal format so that
943assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]944
945</div>
946
947<!-- ======================================================================= -->
948<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
949</div>
950
951<div class="doc_text">
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]952<p>Aggregate constants arise from aggregation of simple constants
953and smaller aggregate constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]954
955<dl>
956 <dt><b>Structure constants</b></dt>
957
958 <dd>Structure constants are represented with notation similar to structure
959 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]960 (<tt>{}</tt>)). For example: "<tt>{ int 4, float 17.0, int* %G }</tt>",
961 where "<tt>%G</tt>" is declared as "<tt>%G = external global int</tt>". Structure constants
962 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]963 types of elements must match those specified by the type.
964 </dd>
965
966 <dt><b>Array constants</b></dt>
967
968 <dd>Array constants are represented with notation similar to array type
969 definitions (a comma separated list of elements, surrounded by square brackets
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]970 (<tt>[]</tt>)). For example: "<tt>[ int 42, int 11, int 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]971 constants must have <a href="#t_array">array type</a>, and the number and
972 types of elements must match those specified by the type.
973 </dd>
974
975 <dt><b>Packed constants</b></dt>
976
977 <dd>Packed constants are represented with notation similar to packed type
978 definitions (a comma separated list of elements, surrounded by
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]979 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; int 42,
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]980 int 11, int 74, int 100 &gt;</tt>". Packed constants must have <a
981 href="#t_packed">packed type</a>, and the number and types of elements must
982 match those specified by the type.
983 </dd>
984
985 <dt><b>Zero initialization</b></dt>
986
987 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
988 value to zero of <em>any</em> type, including scalar and aggregate types.
989 This is often used to avoid having to print large zero initializers (e.g. for
990 large arrays), and is always exactly equivalent to using explicit zero
991 initializers.
992 </dd>
993</dl>
994
995</div>
996
997<!-- ======================================================================= -->
998<div class="doc_subsection">
999 <a name="globalconstants">Global Variable and Function Addresses</a>
1000</div>
1001
1002<div class="doc_text">
1003
1004<p>The addresses of <a href="#globalvars">global variables</a> and <a
1005href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1006constants. These constants are explicitly referenced when the <a
1007href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1008href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1009file:</p>
1010
1011<pre>
1012 %X = global int 17
1013 %Y = global int 42
1014 %Z = global [2 x int*] [ int* %X, int* %Y ]
1015</pre>
1016
1017</div>
1018
1019<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1020<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1021<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1022 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1023 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1024 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1025
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1026 <p>Undefined values indicate to the compiler that the program is well defined
1027 no matter what value is used, giving the compiler more freedom to optimize.
1028 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1029</div>
1030
1031<!-- ======================================================================= -->
1032<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1033</div>
1034
1035<div class="doc_text">
1036
1037<p>Constant expressions are used to allow expressions involving other constants
1038to be used as constants. Constant expressions may be of any <a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1039href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1040that does not have side effects (e.g. load and call are not supported). The
1041following is the syntax for constant expressions:</p>
1042
1043<dl>
1044 <dt><b><tt>cast ( CST to TYPE )</tt></b></dt>
1045
1046 <dd>Cast a constant to another type.</dd>
1047
1048 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1049
1050 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1051 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1052 instruction, the index list may have zero or more indexes, which are required
1053 to make sense for the type of "CSTPTR".</dd>
1054
1055 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1056
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1057 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1058 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1059 binary</a> operations. The constraints on operands are the same as those for
1060 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1061 values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1062</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1063</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]1064
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1065<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1066<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1067<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1068
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1069<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1070
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1071<p>The LLVM instruction set consists of several different
1072classifications of instructions: <a href="#terminators">terminator
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1073instructions</a>, <a href="#binaryops">binary instructions</a>,
1074<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1075 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1076instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1077
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1078</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1079
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1080<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1081<div class="doc_subsection"> <a name="terminators">Terminator
1082Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1083
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1084<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1085
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1086<p>As mentioned <a href="#functionstructure">previously</a>, every
1087basic block in a program ends with a "Terminator" instruction, which
1088indicates which block should be executed after the current block is
1089finished. These terminator instructions typically yield a '<tt>void</tt>'
1090value: they produce control flow, not values (the one exception being
1091the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1092<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1093 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1094instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1095the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1096 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1097 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1098
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1099</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1100
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1101<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1102<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1103Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1104<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1105<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1106<pre> ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1107 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1108</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1109<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1110<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1111value) from a function back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]1112<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1113returns a value and then causes control flow, and one that just causes
1114control flow to occur.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1115<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1116<p>The '<tt>ret</tt>' instruction may return any '<a
1117 href="#t_firstclass">first class</a>' type. Notice that a function is
1118not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1119instruction inside of the function that returns a value that does not
1120match the return type of the function.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1121<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1122<p>When the '<tt>ret</tt>' instruction is executed, control flow
1123returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +0000[diff] [blame]1124 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1125the instruction after the call. If the caller was an "<a
1126 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1127at the beginning of the "normal" destination block. If the instruction
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1128returns a value, that value shall set the call or invoke instruction's
1129return value.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1130<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1131<pre> ret int 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1132 ret void <i>; Return from a void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1133</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1134</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1135<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1136<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1137<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1138<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1139<pre> br bool &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1140</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1141<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1142<p>The '<tt>br</tt>' instruction is used to cause control flow to
1143transfer to a different basic block in the current function. There are
1144two forms of this instruction, corresponding to a conditional branch
1145and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1146<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1147<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1148single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1149unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1150value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1151<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1152<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1153argument is evaluated. If the value is <tt>true</tt>, control flows
1154to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1155control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1156<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1157<pre>Test:<br> %cond = <a href="#i_setcc">seteq</a> int %a, %b<br> br bool %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
1158 href="#i_ret">ret</a> int 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> int 0<br></pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1159</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1160<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1161<div class="doc_subsubsection">
1162 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1163</div>
1164
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1165<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1166<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1167
1168<pre>
1169 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1170</pre>
1171
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1172<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1173
1174<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1175several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1176instruction, allowing a branch to occur to one of many possible
1177destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1178
1179
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1180<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1181
1182<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1183comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1184an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1185table is not allowed to contain duplicate constant entries.</p>
1186
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1187<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1188
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1189<p>The <tt>switch</tt> instruction specifies a table of values and
1190destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1191table is searched for the given value. If the value is found, control flow is
1192transfered to the corresponding destination; otherwise, control flow is
1193transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1194
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1195<h5>Implementation:</h5>
1196
1197<p>Depending on properties of the target machine and the particular
1198<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1199ways. For example, it could be generated as a series of chained conditional
1200branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1201
1202<h5>Example:</h5>
1203
1204<pre>
1205 <i>; Emulate a conditional br instruction</i>
1206 %Val = <a href="#i_cast">cast</a> bool %value to int
1207 switch int %Val, label %truedest [int 0, label %falsedest ]
1208
1209 <i>; Emulate an unconditional br instruction</i>
1210 switch uint 0, label %dest [ ]
1211
1212 <i>; Implement a jump table:</i>
1213 switch uint %val, label %otherwise [ uint 0, label %onzero
1214 uint 1, label %onone
1215 uint 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1216</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1217</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1218
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1219<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1220<div class="doc_subsubsection">
1221 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1222</div>
1223
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1224<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1225
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1226<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1227
1228<pre>
1229 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] &lt;ptr to function ty&gt; %&lt;function ptr val&gt;(&lt;function args&gt;)
1230 to label &lt;normal label&gt; except label &lt;exception label&gt;
1231</pre>
1232
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1233<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1234
1235<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1236function, with the possibility of control flow transfer to either the
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1237'<tt>normal</tt>' label or the
1238'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1239"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1240"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1241href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1242continued at the dynamically nearest "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1243
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1244<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1245
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1246<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1247
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1248<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1249 <li>
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1250 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1251 convention</a> the call should use. If none is specified, the call defaults
1252 to using C calling conventions.
1253 </li>
1254 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1255 function value being invoked. In most cases, this is a direct function
1256 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1257 an arbitrary pointer to function value.
1258 </li>
1259
1260 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1261 function to be invoked. </li>
1262
1263 <li>'<tt>function args</tt>': argument list whose types match the function
1264 signature argument types. If the function signature indicates the function
1265 accepts a variable number of arguments, the extra arguments can be
1266 specified. </li>
1267
1268 <li>'<tt>normal label</tt>': the label reached when the called function
1269 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1270
1271 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1272 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1273
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1274</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1275
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1276<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1277
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1278<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1279href="#i_call">call</a></tt>' instruction in most regards. The primary
1280difference is that it establishes an association with a label, which is used by
1281the runtime library to unwind the stack.</p>
1282
1283<p>This instruction is used in languages with destructors to ensure that proper
1284cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1285exception. Additionally, this is important for implementation of
1286'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1287
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1288<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1289<pre>
1290 %retval = invoke int %Test(int 15) to label %Continue
1291 except label %TestCleanup <i>; {int}:retval set</i>
1292 %retval = invoke <a href="#callingconv">coldcc</a> int %Test(int 15) to label %Continue
1293 except label %TestCleanup <i>; {int}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1294</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1295</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1296
1297
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1298<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1299
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1300<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1301Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1302
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1303<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1304
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1305<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1306<pre>
1307 unwind
1308</pre>
1309
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1310<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1311
1312<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1313at the first callee in the dynamic call stack which used an <a
1314href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1315primarily used to implement exception handling.</p>
1316
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1317<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1318
1319<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1320immediately halt. The dynamic call stack is then searched for the first <a
1321href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1322execution continues at the "exceptional" destination block specified by the
1323<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1324dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1325</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1326
1327<!-- _______________________________________________________________________ -->
1328
1329<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1330Instruction</a> </div>
1331
1332<div class="doc_text">
1333
1334<h5>Syntax:</h5>
1335<pre>
1336 unreachable
1337</pre>
1338
1339<h5>Overview:</h5>
1340
1341<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1342instruction is used to inform the optimizer that a particular portion of the
1343code is not reachable. This can be used to indicate that the code after a
1344no-return function cannot be reached, and other facts.</p>
1345
1346<h5>Semantics:</h5>
1347
1348<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1349</div>
1350
1351
1352
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1353<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1354<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1355<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1356<p>Binary operators are used to do most of the computation in a
1357program. They require two operands, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1358produce a single value. The operands might represent
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1359multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1360The result value of a binary operator is not
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1361necessarily the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1362<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1363</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1364<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1365<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1366Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1367<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1368<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1369<pre> &lt;result&gt; = add &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1370</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1371<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1372<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1373<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1374<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1375 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1376 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1377Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1378<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1379<p>The value produced is the integer or floating point sum of the two
1380operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1381<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1382<pre> &lt;result&gt; = add int 4, %var <i>; yields {int}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1383</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1384</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1385<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1386<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1387Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1388<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1389<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1390<pre> &lt;result&gt; = sub &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1391</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1392<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1393<p>The '<tt>sub</tt>' instruction returns the difference of its two
1394operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1395<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1396instruction present in most other intermediate representations.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1397<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1398<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1399 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1400values.
1401This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1402Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1403<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1404<p>The value produced is the integer or floating point difference of
1405the two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1406<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1407<pre> &lt;result&gt; = sub int 4, %var <i>; yields {int}:result = 4 - %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1408 &lt;result&gt; = sub int 0, %val <i>; yields {int}:result = -%var</i>
1409</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1410</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1411<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1412<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1413Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1414<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1415<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1416<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1417</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1418<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1419<p>The '<tt>mul</tt>' instruction returns the product of its two
1420operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1421<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1422<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1423 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1424values.
1425This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1426Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1427<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1428<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1429two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1430<p>There is no signed vs unsigned multiplication. The appropriate
1431action is taken based on the type of the operand.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1432<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1433<pre> &lt;result&gt; = mul int 4, %var <i>; yields {int}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1434</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1435</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1436<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1437<div class="doc_subsubsection"> <a name="i_div">'<tt>div</tt>'
1438Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1439<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1440<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1441<pre> &lt;result&gt; = div &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1442</pre>
1443<h5>Overview:</h5>
1444<p>The '<tt>div</tt>' instruction returns the quotient of its two
1445operands.</p>
1446<h5>Arguments:</h5>
1447<p>The two arguments to the '<tt>div</tt>' instruction must be either <a
1448 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1449values.
1450This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1451Both arguments must have identical types.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1452<h5>Semantics:</h5>
1453<p>The value produced is the integer or floating point quotient of the
1454two operands.</p>
1455<h5>Example:</h5>
1456<pre> &lt;result&gt; = div int 4, %var <i>; yields {int}:result = 4 / %var</i>
1457</pre>
1458</div>
1459<!-- _______________________________________________________________________ -->
1460<div class="doc_subsubsection"> <a name="i_rem">'<tt>rem</tt>'
1461Instruction</a> </div>
1462<div class="doc_text">
1463<h5>Syntax:</h5>
1464<pre> &lt;result&gt; = rem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1465</pre>
1466<h5>Overview:</h5>
1467<p>The '<tt>rem</tt>' instruction returns the remainder from the
1468division of its two operands.</p>
1469<h5>Arguments:</h5>
1470<p>The two arguments to the '<tt>rem</tt>' instruction must be either <a
1471 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1472values.
1473This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1474Both arguments must have identical types.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1475<h5>Semantics:</h5>
1476<p>This returns the <i>remainder</i> of a division (where the result
1477has the same sign as the divisor), not the <i>modulus</i> (where the
1478result has the same sign as the dividend) of a value. For more
1479information about the difference, see: <a
1480 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1481Math Forum</a>.</p>
1482<h5>Example:</h5>
1483<pre> &lt;result&gt; = rem int 4, %var <i>; yields {int}:result = 4 % %var</i>
1484</pre>
1485</div>
1486<!-- _______________________________________________________________________ -->
1487<div class="doc_subsubsection"> <a name="i_setcc">'<tt>set<i>cc</i></tt>'
1488Instructions</a> </div>
1489<div class="doc_text">
1490<h5>Syntax:</h5>
1491<pre> &lt;result&gt; = seteq &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1492 &lt;result&gt; = setne &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1493 &lt;result&gt; = setlt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1494 &lt;result&gt; = setgt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1495 &lt;result&gt; = setle &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1496 &lt;result&gt; = setge &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1497</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1498<h5>Overview:</h5>
1499<p>The '<tt>set<i>cc</i></tt>' family of instructions returns a boolean
1500value based on a comparison of their two operands.</p>
1501<h5>Arguments:</h5>
1502<p>The two arguments to the '<tt>set<i>cc</i></tt>' instructions must
1503be of <a href="#t_firstclass">first class</a> type (it is not possible
1504to compare '<tt>label</tt>'s, '<tt>array</tt>'s, '<tt>structure</tt>'
1505or '<tt>void</tt>' values, etc...). Both arguments must have identical
1506types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1507<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1508<p>The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1509value if both operands are equal.<br>
1510The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1511value if both operands are unequal.<br>
1512The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1513value if the first operand is less than the second operand.<br>
1514The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1515value if the first operand is greater than the second operand.<br>
1516The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1517value if the first operand is less than or equal to the second operand.<br>
1518The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1519value if the first operand is greater than or equal to the second
1520operand.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1521<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1522<pre> &lt;result&gt; = seteq int 4, 5 <i>; yields {bool}:result = false</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1523 &lt;result&gt; = setne float 4, 5 <i>; yields {bool}:result = true</i>
1524 &lt;result&gt; = setlt uint 4, 5 <i>; yields {bool}:result = true</i>
1525 &lt;result&gt; = setgt sbyte 4, 5 <i>; yields {bool}:result = false</i>
1526 &lt;result&gt; = setle sbyte 4, 5 <i>; yields {bool}:result = true</i>
1527 &lt;result&gt; = setge sbyte 4, 5 <i>; yields {bool}:result = false</i>
1528</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1529</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1530<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1531<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1532Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1533<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1534<p>Bitwise binary operators are used to do various forms of
1535bit-twiddling in a program. They are generally very efficient
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1536instructions and can commonly be strength reduced from other
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1537instructions. They require two operands, execute an operation on them,
1538and produce a single value. The resulting value of the bitwise binary
1539operators is always the same type as its first operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1540</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1541<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1542<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1543Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1544<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1545<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1546<pre> &lt;result&gt; = and &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1547</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1548<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1549<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1550its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1551<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1552<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1553 href="#t_integral">integral</a> values. Both arguments must have
1554identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1555<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1556<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1557<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1558<div style="align: center">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1559<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1560 <tbody>
1561 <tr>
1562 <td>In0</td>
1563 <td>In1</td>
1564 <td>Out</td>
1565 </tr>
1566 <tr>
1567 <td>0</td>
1568 <td>0</td>
1569 <td>0</td>
1570 </tr>
1571 <tr>
1572 <td>0</td>
1573 <td>1</td>
1574 <td>0</td>
1575 </tr>
1576 <tr>
1577 <td>1</td>
1578 <td>0</td>
1579 <td>0</td>
1580 </tr>
1581 <tr>
1582 <td>1</td>
1583 <td>1</td>
1584 <td>1</td>
1585 </tr>
1586 </tbody>
1587</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1588</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1589<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1590<pre> &lt;result&gt; = and int 4, %var <i>; yields {int}:result = 4 &amp; %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1591 &lt;result&gt; = and int 15, 40 <i>; yields {int}:result = 8</i>
1592 &lt;result&gt; = and int 4, 8 <i>; yields {int}:result = 0</i>
1593</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1594</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1595<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1596<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1597<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1598<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1599<pre> &lt;result&gt; = or &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1600</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1601<h5>Overview:</h5>
1602<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1603or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1604<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1605<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1606 href="#t_integral">integral</a> values. Both arguments must have
1607identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1608<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1609<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1610<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1611<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1612<table border="1" cellspacing="0" cellpadding="4">
1613 <tbody>
1614 <tr>
1615 <td>In0</td>
1616 <td>In1</td>
1617 <td>Out</td>
1618 </tr>
1619 <tr>
1620 <td>0</td>
1621 <td>0</td>
1622 <td>0</td>
1623 </tr>
1624 <tr>
1625 <td>0</td>
1626 <td>1</td>
1627 <td>1</td>
1628 </tr>
1629 <tr>
1630 <td>1</td>
1631 <td>0</td>
1632 <td>1</td>
1633 </tr>
1634 <tr>
1635 <td>1</td>
1636 <td>1</td>
1637 <td>1</td>
1638 </tr>
1639 </tbody>
1640</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1641</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1642<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1643<pre> &lt;result&gt; = or int 4, %var <i>; yields {int}:result = 4 | %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1644 &lt;result&gt; = or int 15, 40 <i>; yields {int}:result = 47</i>
1645 &lt;result&gt; = or int 4, 8 <i>; yields {int}:result = 12</i>
1646</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1647</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1648<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1649<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
1650Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1651<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1652<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1653<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1654</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1655<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1656<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
1657or of its two operands. The <tt>xor</tt> is used to implement the
1658"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1659<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1660<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1661 href="#t_integral">integral</a> values. Both arguments must have
1662identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1663<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1664<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1665<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1666<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1667<table border="1" cellspacing="0" cellpadding="4">
1668 <tbody>
1669 <tr>
1670 <td>In0</td>
1671 <td>In1</td>
1672 <td>Out</td>
1673 </tr>
1674 <tr>
1675 <td>0</td>
1676 <td>0</td>
1677 <td>0</td>
1678 </tr>
1679 <tr>
1680 <td>0</td>
1681 <td>1</td>
1682 <td>1</td>
1683 </tr>
1684 <tr>
1685 <td>1</td>
1686 <td>0</td>
1687 <td>1</td>
1688 </tr>
1689 <tr>
1690 <td>1</td>
1691 <td>1</td>
1692 <td>0</td>
1693 </tr>
1694 </tbody>
1695</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1696</div>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1697<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1698<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1699<pre> &lt;result&gt; = xor int 4, %var <i>; yields {int}:result = 4 ^ %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1700 &lt;result&gt; = xor int 15, 40 <i>; yields {int}:result = 39</i>
1701 &lt;result&gt; = xor int 4, 8 <i>; yields {int}:result = 12</i>
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1702 &lt;result&gt; = xor int %V, -1 <i>; yields {int}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1703</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1704</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1705<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1706<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
1707Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1708<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1709<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1710<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1711</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1712<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1713<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
1714the left a specified number of bits.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1715<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1716<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1717 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1718type.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1719<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1720<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1721<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1722<pre> &lt;result&gt; = shl int 4, ubyte %var <i>; yields {int}:result = 4 &lt;&lt; %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1723 &lt;result&gt; = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
1724 &lt;result&gt; = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
1725</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1726</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1727<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1728<div class="doc_subsubsection"> <a name="i_shr">'<tt>shr</tt>'
1729Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1730<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1731<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1732<pre> &lt;result&gt; = shr &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1733</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1734<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1735<p>The '<tt>shr</tt>' instruction returns the first operand shifted to
1736the right a specified number of bits.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1737<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1738<p>The first argument to the '<tt>shr</tt>' instruction must be an <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1739 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1740type.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1741<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1742<p>If the first argument is a <a href="#t_signed">signed</a> type, the
1743most significant bit is duplicated in the newly free'd bit positions.
1744If the first argument is unsigned, zero bits shall fill the empty
1745positions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1746<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1747<pre> &lt;result&gt; = shr int 4, ubyte %var <i>; yields {int}:result = 4 &gt;&gt; %var</i>
Chris Lattner33426d92003-06-18 21:30:51 +0000[diff] [blame]1748 &lt;result&gt; = shr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1749 &lt;result&gt; = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
Chris Lattner33426d92003-06-18 21:30:51 +0000[diff] [blame]1750 &lt;result&gt; = shr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i>
1751 &lt;result&gt; = shr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1752</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1753</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1754<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1755<div class="doc_subsection"> <a name="memoryops">Memory Access
1756Operations</a></div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1757<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1758<p>A key design point of an SSA-based representation is how it
1759represents memory. In LLVM, no memory locations are in SSA form, which
1760makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1761allocate, and free memory in LLVM.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1762</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1763<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1764<div class="doc_subsubsection"> <a name="i_malloc">'<tt>malloc</tt>'
1765Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1766<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1767<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1768<pre> &lt;result&gt; = malloc &lt;type&gt;, uint &lt;NumElements&gt; <i>; yields {type*}:result</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1769 &lt;result&gt; = malloc &lt;type&gt; <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1770</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1771<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1772<p>The '<tt>malloc</tt>' instruction allocates memory from the system
1773heap and returns a pointer to it.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1774<h5>Arguments:</h5>
John Criswella92e5862004-02-24 16:13:56 +0000[diff] [blame]1775<p>The '<tt>malloc</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
1776bytes of memory from the operating system and returns a pointer of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1777appropriate type to the program. The second form of the instruction is
1778a shorter version of the first instruction that defaults to allocating
1779one element.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1780<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1781<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1782<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
1783a pointer is returned.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1784<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1785<pre> %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1786
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1787 %size = <a
1788 href="#i_add">add</a> uint 2, 2 <i>; yields {uint}:size = uint 4</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1789 %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i>
1790 %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1791</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1792</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1793<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1794<div class="doc_subsubsection"> <a name="i_free">'<tt>free</tt>'
1795Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1796<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1797<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1798<pre> free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1799</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1800<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1801<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1802memory heap to be reallocated in the future.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1803<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1804<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1805<p>'<tt>value</tt>' shall be a pointer value that points to a value
1806that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
1807instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1808<h5>Semantics:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1809<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1810after this instruction executes.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1811<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1812<pre> %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1813 free [4 x ubyte]* %array
1814</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1815</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1816<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1817<div class="doc_subsubsection"> <a name="i_alloca">'<tt>alloca</tt>'
1818Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1819<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1820<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1821<pre> &lt;result&gt; = alloca &lt;type&gt;, uint &lt;NumElements&gt; <i>; yields {type*}:result</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1822 &lt;result&gt; = alloca &lt;type&gt; <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1823</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1824<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1825<p>The '<tt>alloca</tt>' instruction allocates memory on the current
1826stack frame of the procedure that is live until the current function
1827returns to its caller.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1828<h5>Arguments:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1829<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1830bytes of memory on the runtime stack, returning a pointer of the
1831appropriate type to the program. The second form of the instruction is
1832a shorter version of the first that defaults to allocating one element.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1833<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1834<h5>Semantics:</h5>
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1835<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1836memory is automatically released when the function returns. The '<tt>alloca</tt>'
1837instruction is commonly used to represent automatic variables that must
1838have an address available. When the function returns (either with the <tt><a
John Criswellc932bef2005-05-12 16:55:34 +0000[diff] [blame]1839 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1840instructions), the memory is reclaimed.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1841<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1842<pre> %ptr = alloca int <i>; yields {int*}:ptr</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1843 %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1844</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1845</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1846<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1847<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
1848Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1849<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1850<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1851<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;<br></pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1852<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1853<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1854<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1855<p>The argument to the '<tt>load</tt>' instruction specifies the memory
1856address to load from. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]1857 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1858marked as <tt>volatile</tt> then the optimizer is not allowed to modify
1859the number or order of execution of this <tt>load</tt> with other
1860volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
1861instructions. </p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1862<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1863<p>The location of memory pointed to is loaded.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1864<h5>Examples:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1865<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
1866 <a
1867 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1868 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
1869</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1870</div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1871<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1872<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
1873Instruction</a> </div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1874<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1875<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattner12d456c2003-09-08 18:27:49 +0000[diff] [blame]1876 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1877</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1878<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1879<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1880<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1881<p>There are two arguments to the '<tt>store</tt>' instruction: a value
1882to store and an address to store it into. The type of the '<tt>&lt;pointer&gt;</tt>'
1883operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1884operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1885optimizer is not allowed to modify the number or order of execution of
1886this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
1887 href="#i_store">store</a></tt> instructions.</p>
1888<h5>Semantics:</h5>
1889<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
1890at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1891<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1892<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
1893 <a
1894 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1895 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
1896</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1897<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1898<div class="doc_subsubsection">
1899 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
1900</div>
1901
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1902<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1903<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1904<pre>
1905 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
1906</pre>
1907
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1908<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1909
1910<p>
1911The '<tt>getelementptr</tt>' instruction is used to get the address of a
1912subelement of an aggregate data structure.</p>
1913
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1914<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1915
1916<p>This instruction takes a list of integer constants that indicate what
1917elements of the aggregate object to index to. The actual types of the arguments
1918provided depend on the type of the first pointer argument. The
1919'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]1920levels of a structure or to a specific index in an array. When indexing into a
1921structure, only <tt>uint</tt>
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1922integer constants are allowed. When indexing into an array or pointer,
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1923<tt>int</tt> and <tt>long</tt> indexes are allowed of any sign.</p>
1924
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1925<p>For example, let's consider a C code fragment and how it gets
1926compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1927
1928<pre>
1929 struct RT {
1930 char A;
1931 int B[10][20];
1932 char C;
1933 };
1934 struct ST {
1935 int X;
1936 double Y;
1937 struct RT Z;
1938 };
1939
1940 int *foo(struct ST *s) {
1941 return &amp;s[1].Z.B[5][13];
1942 }
1943</pre>
1944
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1945<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1946
1947<pre>
1948 %RT = type { sbyte, [10 x [20 x int]], sbyte }
1949 %ST = type { int, double, %RT }
1950
Brian Gaeke317ef962004-07-02 21:08:14 +0000[diff] [blame]1951 implementation
1952
1953 int* %foo(%ST* %s) {
1954 entry:
1955 %reg = getelementptr %ST* %s, int 1, uint 2, uint 1, int 5, int 13
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1956 ret int* %reg
1957 }
1958</pre>
1959
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1960<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1961
1962<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1963on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]1964and <a href="#t_array">array</a> types require <tt>uint</tt>, <tt>int</tt>,
1965<tt>ulong</tt>, or <tt>long</tt> values, and <a href="#t_struct">structure</a>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1966types require <tt>uint</tt> <b>constants</b>.</p>
1967
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1968<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1969type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT
1970}</tt>' type, a structure. The second index indexes into the third element of
1971the structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]],
1972sbyte }</tt>' type, another structure. The third index indexes into the second
1973element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an
1974array. The two dimensions of the array are subscripted into, yielding an
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]1975'<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1976to this element, thus computing a value of '<tt>int*</tt>' type.</p>
1977
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1978<p>Note that it is perfectly legal to index partially through a
1979structure, returning a pointer to an inner element. Because of this,
1980the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1981
1982<pre>
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1983 int* %foo(%ST* %s) {
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1984 %t1 = getelementptr %ST* %s, int 1 <i>; yields %ST*:%t1</i>
1985 %t2 = getelementptr %ST* %t1, int 0, uint 2 <i>; yields %RT*:%t2</i>
1986 %t3 = getelementptr %RT* %t2, int 0, uint 1 <i>; yields [10 x [20 x int]]*:%t3</i>
1987 %t4 = getelementptr [10 x [20 x int]]* %t3, int 0, int 5 <i>; yields [20 x int]*:%t4</i>
1988 %t5 = getelementptr [20 x int]* %t4, int 0, int 13 <i>; yields int*:%t5</i>
1989 ret int* %t5
1990 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1991</pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1992<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1993<pre>
1994 <i>; yields [12 x ubyte]*:aptr</i>
1995 %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, uint 1
1996</pre>
1997
1998</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1999<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2000<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2001<div class="doc_text">
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]2002<p>The instructions in this category are the "miscellaneous"
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2003instructions, which defy better classification.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2004</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2005<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2006<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
2007Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2008<div class="doc_text">
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2009<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2010<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2011<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2012<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
2013the SSA graph representing the function.</p>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2014<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2015<p>The type of the incoming values are specified with the first type
2016field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
2017as arguments, with one pair for each predecessor basic block of the
2018current block. Only values of <a href="#t_firstclass">first class</a>
2019type may be used as the value arguments to the PHI node. Only labels
2020may be used as the label arguments.</p>
2021<p>There must be no non-phi instructions between the start of a basic
2022block and the PHI instructions: i.e. PHI instructions must be first in
2023a basic block.</p>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2024<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2025<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
2026value specified by the parameter, depending on which basic block we
2027came from in the last <a href="#terminators">terminator</a> instruction.</p>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2028<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2029<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi uint [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add uint %indvar, 1<br> br label %Loop<br></pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2030</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2031
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2032<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2033<div class="doc_subsubsection">
2034 <a name="i_cast">'<tt>cast .. to</tt>' Instruction</a>
2035</div>
2036
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2037<div class="doc_text">
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2038
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2039<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2040
2041<pre>
2042 &lt;result&gt; = cast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2043</pre>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2044
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2045<h5>Overview:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2046
2047<p>
2048The '<tt>cast</tt>' instruction is used as the primitive means to convert
2049integers to floating point, change data type sizes, and break type safety (by
2050casting pointers).
2051</p>
2052
2053
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2054<h5>Arguments:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2055
2056<p>
2057The '<tt>cast</tt>' instruction takes a value to cast, which must be a first
2058class value, and a type to cast it to, which must also be a <a
2059href="#t_firstclass">first class</a> type.
2060</p>
2061
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2062<h5>Semantics:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2063
2064<p>
2065This instruction follows the C rules for explicit casts when determining how the
2066data being cast must change to fit in its new container.
2067</p>
2068
2069<p>
2070When casting to bool, any value that would be considered true in the context of
2071a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' values,
2072all else are '<tt>false</tt>'.
2073</p>
2074
2075<p>
2076When extending an integral value from a type of one signness to another (for
2077example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value is sign-extended if the
2078<b>source</b> value is signed, and zero-extended if the source value is
2079unsigned. <tt>bool</tt> values are always zero extended into either zero or
2080one.
2081</p>
2082
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2083<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2084
2085<pre>
2086 %X = cast int 257 to ubyte <i>; yields ubyte:1</i>
Chris Lattnerd8f8ede2002-06-25 18:03:17 +0000[diff] [blame]2087 %Y = cast int 123 to bool <i>; yields bool:true</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2088</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2089</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2090
2091<!-- _______________________________________________________________________ -->
2092<div class="doc_subsubsection">
2093 <a name="i_select">'<tt>select</tt>' Instruction</a>
2094</div>
2095
2096<div class="doc_text">
2097
2098<h5>Syntax:</h5>
2099
2100<pre>
2101 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
2102</pre>
2103
2104<h5>Overview:</h5>
2105
2106<p>
2107The '<tt>select</tt>' instruction is used to choose one value based on a
2108condition, without branching.
2109</p>
2110
2111
2112<h5>Arguments:</h5>
2113
2114<p>
2115The '<tt>select</tt>' instruction requires a boolean value indicating the condition, and two values of the same <a href="#t_firstclass">first class</a> type.
2116</p>
2117
2118<h5>Semantics:</h5>
2119
2120<p>
2121If the boolean condition evaluates to true, the instruction returns the first
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2122value argument; otherwise, it returns the second value argument.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2123</p>
2124
2125<h5>Example:</h5>
2126
2127<pre>
2128 %X = select bool true, ubyte 17, ubyte 42 <i>; yields ubyte:17</i>
2129</pre>
2130</div>
2131
2132
2133
2134
2135
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2136<!-- _______________________________________________________________________ -->
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2137<div class="doc_subsubsection">
2138 <a name="i_call">'<tt>call</tt>' Instruction</a>
2139</div>
2140
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2141<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2142
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2143<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2144<pre>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2145 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] &lt;ty&gt;* &lt;fnptrval&gt;(&lt;param list&gt;)
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2146</pre>
2147
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2148<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2149
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2150<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2151
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2152<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2153
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2154<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2155
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2156<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2157 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2158 <p>The optional "tail" marker indicates whether the callee function accesses
2159 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2160 function call is eligible for tail call optimization. Note that calls may
2161 be marked "tail" even if they do not occur before a <a
2162 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2163 </li>
2164 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2165 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
2166 convention</a> the call should use. If none is specified, the call defaults
2167 to using C calling conventions.
2168 </li>
2169 <li>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2170 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
2171 being invoked. The argument types must match the types implied by this
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2172 signature. This type can be omitted if the function is not varargs and
2173 if the function type does not return a pointer to a function.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2174 </li>
2175 <li>
2176 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
2177 be invoked. In most cases, this is a direct function invocation, but
2178 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2179 to function value.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2180 </li>
2181 <li>
2182 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +0000[diff] [blame]2183 function signature argument types. All arguments must be of
2184 <a href="#t_firstclass">first class</a> type. If the function signature
2185 indicates the function accepts a variable number of arguments, the extra
2186 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2187 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2188</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2189
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2190<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2191
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2192<p>The '<tt>call</tt>' instruction is used to cause control flow to
2193transfer to a specified function, with its incoming arguments bound to
2194the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
2195instruction in the called function, control flow continues with the
2196instruction after the function call, and the return value of the
2197function is bound to the result argument. This is a simpler case of
2198the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2199
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2200<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2201
2202<pre>
2203 %retval = call int %test(int %argc)
2204 call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42);
2205 %X = tail call int %foo()
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2206 %Y = tail call <a href="#callingconv">fastcc</a> int %foo()
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2207</pre>
2208
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2209</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2210
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2211<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2212<div class="doc_subsubsection">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2213 <a name="i_vaarg">'<tt>vaarg</tt>' Instruction</a>
2214</div>
2215
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2216<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2217
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]2218<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2219
2220<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2221 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2222</pre>
2223
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]2224<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2225
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2226<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2227the "variable argument" area of a function call. It is used to implement the
2228<tt>va_arg</tt> macro in C.</p>
2229
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]2230<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2231
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2232<p>This instruction takes a <tt>va_list*</tt> value and the type of
2233the argument. It returns a value of the specified argument type and
2234increments the <tt>va_list</tt> to poin to the next argument. Again, the
2235actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2236
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]2237<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2238
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2239<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
2240type from the specified <tt>va_list</tt> and causes the
2241<tt>va_list</tt> to point to the next argument. For more information,
2242see the variable argument handling <a href="#int_varargs">Intrinsic
2243Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2244
2245<p>It is legal for this instruction to be called in a function which does not
2246take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2247function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2248
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2249<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2250href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2251argument.</p>
2252
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]2253<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2254
2255<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
2256
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2257</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2258
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2259<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2260<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
2261<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2262
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2263<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2264
2265<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2266well known names and semantics and are required to follow certain
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2267restrictions. Overall, these instructions represent an extension mechanism for
2268the LLVM language that does not require changing all of the transformations in
2269LLVM to add to the language (or the bytecode reader/writer, the parser,
2270etc...).</p>
2271
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2272<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
2273prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2274this. Intrinsic functions must always be external functions: you cannot define
2275the body of intrinsic functions. Intrinsic functions may only be used in call
2276or invoke instructions: it is illegal to take the address of an intrinsic
2277function. Additionally, because intrinsic functions are part of the LLVM
2278language, it is required that they all be documented here if any are added.</p>
2279
2280
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2281<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner90391c12005-05-11 03:35:57 +0000[diff] [blame]2282href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2283</p>
2284
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2285</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2286
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2287<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2288<div class="doc_subsection">
2289 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
2290</div>
2291
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2292<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2293
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2294<p>Variable argument support is defined in LLVM with the <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2295 href="#i_vanext"><tt>vanext</tt></a> instruction and these three
2296intrinsic functions. These functions are related to the similarly
2297named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2298
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2299<p>All of these functions operate on arguments that use a
2300target-specific value type "<tt>va_list</tt>". The LLVM assembly
2301language reference manual does not define what this type is, so all
2302transformations should be prepared to handle intrinsics with any type
2303used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2304
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2305<p>This example shows how the <a href="#i_vanext"><tt>vanext</tt></a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2306instruction and the variable argument handling intrinsic functions are
2307used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2308
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2309<pre>
2310int %test(int %X, ...) {
2311 ; Initialize variable argument processing
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2312 %ap = alloca sbyte*
2313 call void %<a href="#i_va_start">llvm.va_start</a>(sbyte** %ap)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2314
2315 ; Read a single integer argument
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2316 %tmp = va_arg sbyte** %ap, int
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2317
2318 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2319 %aq = alloca sbyte*
Andrew Lenharth5305ea52005-06-22 20:38:11 +0000[diff] [blame^]2320 call void %<a href="#i_va_copy">llvm.va_copy</a>(sbyte** %aq, sbyte** %ap)
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2321 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %aq)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2322
2323 ; Stop processing of arguments.
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2324 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %ap)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2325 ret int %tmp
2326}
2327</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2328</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2329
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2330<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2331<div class="doc_subsubsection">
2332 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
2333</div>
2334
2335
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2336<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2337<h5>Syntax:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2338<pre> declare void %llvm.va_start(&lt;va_list&gt;* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2339<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2340<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
2341<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
2342href="#i_va_arg">va_arg</a></tt>.</p>
2343
2344<h5>Arguments:</h5>
2345
2346<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
2347
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2348<h5>Semantics:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2349
2350<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
2351macro available in C. In a target-dependent way, it initializes the
2352<tt>va_list</tt> element the argument points to, so that the next call to
2353<tt>va_arg</tt> will produce the first variable argument passed to the function.
2354Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
2355last argument of the function, the compiler can figure that out.</p>
2356
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2357</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2358
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2359<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2360<div class="doc_subsubsection">
2361 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
2362</div>
2363
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2364<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2365<h5>Syntax:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2366<pre> declare void %llvm.va_end(&lt;va_list*&gt; &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2367<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2368<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
2369which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
2370or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2371<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2372<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2373<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2374<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2375macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
2376Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
2377 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
2378with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2379</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2380
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2381<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2382<div class="doc_subsubsection">
2383 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
2384</div>
2385
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2386<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2387
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2388<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2389
2390<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2391 declare void %llvm.va_copy(&lt;va_list&gt;* &lt;destarglist&gt;,
Andrew Lenharth5305ea52005-06-22 20:38:11 +0000[diff] [blame^]2392 &lt;va_list&gt;* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2393</pre>
2394
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2395<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2396
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2397<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
2398the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2399
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2400<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2401
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2402<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Andrew Lenharth5305ea52005-06-22 20:38:11 +0000[diff] [blame^]2403The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2404
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2405
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2406<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2407
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]2408<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
2409available in C. In a target-dependent way, it copies the source
2410<tt>va_list</tt> element into the destination list. This intrinsic is necessary
2411because the <tt><a href="i_va_begin">llvm.va_begin</a></tt> intrinsic may be
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2412arbitrarily complex and require memory allocation, for example.</p>
2413
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2414</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2415
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2416<!-- ======================================================================= -->
2417<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2418 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
2419</div>
2420
2421<div class="doc_text">
2422
2423<p>
2424LLVM support for <a href="GarbageCollection.html">Accurate Garbage
2425Collection</a> requires the implementation and generation of these intrinsics.
2426These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
2427stack</a>, as well as garbage collector implementations that require <a
2428href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
2429Front-ends for type-safe garbage collected languages should generate these
2430intrinsics to make use of the LLVM garbage collectors. For more details, see <a
2431href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
2432</p>
2433</div>
2434
2435<!-- _______________________________________________________________________ -->
2436<div class="doc_subsubsection">
2437 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
2438</div>
2439
2440<div class="doc_text">
2441
2442<h5>Syntax:</h5>
2443
2444<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2445 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2446</pre>
2447
2448<h5>Overview:</h5>
2449
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2450<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2451the code generator, and allows some metadata to be associated with it.</p>
2452
2453<h5>Arguments:</h5>
2454
2455<p>The first argument specifies the address of a stack object that contains the
2456root pointer. The second pointer (which must be either a constant or a global
2457value address) contains the meta-data to be associated with the root.</p>
2458
2459<h5>Semantics:</h5>
2460
2461<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
2462location. At compile-time, the code generator generates information to allow
2463the runtime to find the pointer at GC safe points.
2464</p>
2465
2466</div>
2467
2468
2469<!-- _______________________________________________________________________ -->
2470<div class="doc_subsubsection">
2471 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
2472</div>
2473
2474<div class="doc_text">
2475
2476<h5>Syntax:</h5>
2477
2478<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2479 declare sbyte* %llvm.gcread(sbyte** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2480</pre>
2481
2482<h5>Overview:</h5>
2483
2484<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
2485locations, allowing garbage collector implementations that require read
2486barriers.</p>
2487
2488<h5>Arguments:</h5>
2489
2490<p>The argument is the address to read from, which should be an address
2491allocated from the garbage collector.</p>
2492
2493<h5>Semantics:</h5>
2494
2495<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
2496instruction, but may be replaced with substantially more complex code by the
2497garbage collector runtime, as needed.</p>
2498
2499</div>
2500
2501
2502<!-- _______________________________________________________________________ -->
2503<div class="doc_subsubsection">
2504 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
2505</div>
2506
2507<div class="doc_text">
2508
2509<h5>Syntax:</h5>
2510
2511<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2512 declare void %llvm.gcwrite(sbyte* %P1, sbyte** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2513</pre>
2514
2515<h5>Overview:</h5>
2516
2517<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
2518locations, allowing garbage collector implementations that require write
2519barriers (such as generational or reference counting collectors).</p>
2520
2521<h5>Arguments:</h5>
2522
2523<p>The first argument is the reference to store, and the second is the heap
2524location to store to.</p>
2525
2526<h5>Semantics:</h5>
2527
2528<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
2529instruction, but may be replaced with substantially more complex code by the
2530garbage collector runtime, as needed.</p>
2531
2532</div>
2533
2534
2535
2536<!-- ======================================================================= -->
2537<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]2538 <a name="int_codegen">Code Generator Intrinsics</a>
2539</div>
2540
2541<div class="doc_text">
2542<p>
2543These intrinsics are provided by LLVM to expose special features that may only
2544be implemented with code generator support.
2545</p>
2546
2547</div>
2548
2549<!-- _______________________________________________________________________ -->
2550<div class="doc_subsubsection">
2551 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
2552</div>
2553
2554<div class="doc_text">
2555
2556<h5>Syntax:</h5>
2557<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2558 declare void* %llvm.returnaddress(uint &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]2559</pre>
2560
2561<h5>Overview:</h5>
2562
2563<p>
2564The '<tt>llvm.returnaddress</tt>' intrinsic returns a target-specific value
2565indicating the return address of the current function or one of its callers.
2566</p>
2567
2568<h5>Arguments:</h5>
2569
2570<p>
2571The argument to this intrinsic indicates which function to return the address
2572for. Zero indicates the calling function, one indicates its caller, etc. The
2573argument is <b>required</b> to be a constant integer value.
2574</p>
2575
2576<h5>Semantics:</h5>
2577
2578<p>
2579The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
2580the return address of the specified call frame, or zero if it cannot be
2581identified. The value returned by this intrinsic is likely to be incorrect or 0
2582for arguments other than zero, so it should only be used for debugging purposes.
2583</p>
2584
2585<p>
2586Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]2587aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]2588source-language caller.
2589</p>
2590</div>
2591
2592
2593<!-- _______________________________________________________________________ -->
2594<div class="doc_subsubsection">
2595 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
2596</div>
2597
2598<div class="doc_text">
2599
2600<h5>Syntax:</h5>
2601<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2602 declare void* %llvm.frameaddress(uint &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]2603</pre>
2604
2605<h5>Overview:</h5>
2606
2607<p>
2608The '<tt>llvm.frameaddress</tt>' intrinsic returns the target-specific frame
2609pointer value for the specified stack frame.
2610</p>
2611
2612<h5>Arguments:</h5>
2613
2614<p>
2615The argument to this intrinsic indicates which function to return the frame
2616pointer for. Zero indicates the calling function, one indicates its caller,
2617etc. The argument is <b>required</b> to be a constant integer value.
2618</p>
2619
2620<h5>Semantics:</h5>
2621
2622<p>
2623The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
2624the frame address of the specified call frame, or zero if it cannot be
2625identified. The value returned by this intrinsic is likely to be incorrect or 0
2626for arguments other than zero, so it should only be used for debugging purposes.
2627</p>
2628
2629<p>
2630Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]2631aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]2632source-language caller.
2633</p>
2634</div>
2635
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]2636<!-- _______________________________________________________________________ -->
2637<div class="doc_subsubsection">
2638 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
2639</div>
2640
2641<div class="doc_text">
2642
2643<h5>Syntax:</h5>
2644<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2645 declare void %llvm.prefetch(sbyte * &lt;address&gt;,
2646 uint &lt;rw&gt;, uint &lt;locality&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]2647</pre>
2648
2649<h5>Overview:</h5>
2650
2651
2652<p>
2653The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2654a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
2655no
2656effect on the behavior of the program but can change its performance
Chris Lattnerff851072005-02-28 19:47:14 +0000[diff] [blame]2657characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]2658</p>
2659
2660<h5>Arguments:</h5>
2661
2662<p>
2663<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
2664determining if the fetch should be for a read (0) or write (1), and
2665<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +0000[diff] [blame]2666locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]2667<tt>locality</tt> arguments must be constant integers.
2668</p>
2669
2670<h5>Semantics:</h5>
2671
2672<p>
2673This intrinsic does not modify the behavior of the program. In particular,
2674prefetches cannot trap and do not produce a value. On targets that support this
2675intrinsic, the prefetch can provide hints to the processor cache for better
2676performance.
2677</p>
2678
2679</div>
2680
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]2681<!-- _______________________________________________________________________ -->
2682<div class="doc_subsubsection">
2683 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
2684</div>
2685
2686<div class="doc_text">
2687
2688<h5>Syntax:</h5>
2689<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2690 declare void %llvm.pcmarker( uint &lt;id&gt; )
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]2691</pre>
2692
2693<h5>Overview:</h5>
2694
2695
2696<p>
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2697The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
2698(PC) in a region of
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]2699code to simulators and other tools. The method is target specific, but it is
2700expected that the marker will use exported symbols to transmit the PC of the marker.
2701The marker makes no guaranties that it will remain with any specific instruction
2702after optimizations. It is possible that the presense of a marker will inhibit
2703optimizations. The intended use is to be inserted after optmizations to allow
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2704correlations of simulation runs.
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]2705</p>
2706
2707<h5>Arguments:</h5>
2708
2709<p>
2710<tt>id</tt> is a numerical id identifying the marker.
2711</p>
2712
2713<h5>Semantics:</h5>
2714
2715<p>
2716This intrinsic does not modify the behavior of the program. Backends that do not
2717support this intrinisic may ignore it.
2718</p>
2719
2720</div>
2721
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]2722
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]2723<!-- ======================================================================= -->
2724<div class="doc_subsection">
2725 <a name="int_os">Operating System Intrinsics</a>
2726</div>
2727
2728<div class="doc_text">
2729<p>
2730These intrinsics are provided by LLVM to support the implementation of
2731operating system level code.
2732</p>
2733
2734</div>
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2735
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2736<!-- _______________________________________________________________________ -->
2737<div class="doc_subsubsection">
2738 <a name="i_readport">'<tt>llvm.readport</tt>' Intrinsic</a>
2739</div>
2740
2741<div class="doc_text">
2742
2743<h5>Syntax:</h5>
2744<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2745 declare &lt;integer type&gt; %llvm.readport (&lt;integer type&gt; &lt;address&gt;)
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2746</pre>
2747
2748<h5>Overview:</h5>
2749
2750<p>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]2751The '<tt>llvm.readport</tt>' intrinsic reads data from the specified hardware
2752I/O port.
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2753</p>
2754
2755<h5>Arguments:</h5>
2756
2757<p>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]2758The argument to this intrinsic indicates the hardware I/O address from which
2759to read the data. The address is in the hardware I/O address namespace (as
2760opposed to being a memory location for memory mapped I/O).
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2761</p>
2762
2763<h5>Semantics:</h5>
2764
2765<p>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]2766The '<tt>llvm.readport</tt>' intrinsic reads data from the hardware I/O port
2767specified by <i>address</i> and returns the value. The address and return
2768value must be integers, but the size is dependent upon the platform upon which
2769the program is code generated. For example, on x86, the address must be an
Misha Brukman36c6bc12005-04-22 18:02:52 +0000[diff] [blame]2770unsigned 16-bit value, and the return value must be 8, 16, or 32 bits.
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2771</p>
2772
2773</div>
2774
2775<!-- _______________________________________________________________________ -->
2776<div class="doc_subsubsection">
2777 <a name="i_writeport">'<tt>llvm.writeport</tt>' Intrinsic</a>
2778</div>
2779
2780<div class="doc_text">
2781
2782<h5>Syntax:</h5>
2783<pre>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2784 call void (&lt;integer type&gt;, &lt;integer type&gt;)*
2785 %llvm.writeport (&lt;integer type&gt; &lt;value&gt;,
2786 &lt;integer type&gt; &lt;address&gt;)
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2787</pre>
2788
2789<h5>Overview:</h5>
2790
2791<p>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]2792The '<tt>llvm.writeport</tt>' intrinsic writes data to the specified hardware
2793I/O port.
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2794</p>
2795
2796<h5>Arguments:</h5>
2797
2798<p>
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2799The first argument is the value to write to the I/O port.
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2800</p>
2801
2802<p>
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2803The second argument indicates the hardware I/O address to which data should be
2804written. The address is in the hardware I/O address namespace (as opposed to
2805being a memory location for memory mapped I/O).
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2806</p>
2807
2808<h5>Semantics:</h5>
2809
2810<p>
2811The '<tt>llvm.writeport</tt>' intrinsic writes <i>value</i> to the I/O port
2812specified by <i>address</i>. The address and value must be integers, but the
2813size is dependent upon the platform upon which the program is code generated.
Misha Brukman36c6bc12005-04-22 18:02:52 +0000[diff] [blame]2814For example, on x86, the address must be an unsigned 16-bit value, and the
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]2815value written must be 8, 16, or 32 bits in length.
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2816</p>
2817
2818</div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]2819
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2820<!-- _______________________________________________________________________ -->
2821<div class="doc_subsubsection">
2822 <a name="i_readio">'<tt>llvm.readio</tt>' Intrinsic</a>
2823</div>
2824
2825<div class="doc_text">
2826
2827<h5>Syntax:</h5>
2828<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2829 declare &lt;result&gt; %llvm.readio (&lt;ty&gt; * &lt;pointer&gt;)
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2830</pre>
2831
2832<h5>Overview:</h5>
2833
2834<p>
2835The '<tt>llvm.readio</tt>' intrinsic reads data from a memory mapped I/O
2836address.
2837</p>
2838
2839<h5>Arguments:</h5>
2840
2841<p>
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2842The argument to this intrinsic is a pointer indicating the memory address from
2843which to read the data. The data must be a
2844<a href="#t_firstclass">first class</a> type.
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2845</p>
2846
2847<h5>Semantics:</h5>
2848
2849<p>
2850The '<tt>llvm.readio</tt>' intrinsic reads data from a memory mapped I/O
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2851location specified by <i>pointer</i> and returns the value. The argument must
2852be a pointer, and the return value must be a
2853<a href="#t_firstclass">first class</a> type. However, certain architectures
Misha Brukman36c6bc12005-04-22 18:02:52 +0000[diff] [blame]2854may not support I/O on all first class types. For example, 32-bit processors
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2855may only support I/O on data types that are 32 bits or less.
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2856</p>
2857
2858<p>
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2859This intrinsic enforces an in-order memory model for llvm.readio and
2860llvm.writeio calls on machines that use dynamic scheduling. Dynamically
2861scheduled processors may execute loads and stores out of order, re-ordering at
2862run time accesses to memory mapped I/O registers. Using these intrinsics
2863ensures that accesses to memory mapped I/O registers occur in program order.
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2864</p>
2865
2866</div>
2867
2868<!-- _______________________________________________________________________ -->
2869<div class="doc_subsubsection">
2870 <a name="i_writeio">'<tt>llvm.writeio</tt>' Intrinsic</a>
2871</div>
2872
2873<div class="doc_text">
2874
2875<h5>Syntax:</h5>
2876<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2877 declare void %llvm.writeio (&lt;ty1&gt; &lt;value&gt;, &lt;ty2&gt; * &lt;pointer&gt;)
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2878</pre>
2879
2880<h5>Overview:</h5>
2881
2882<p>
2883The '<tt>llvm.writeio</tt>' intrinsic writes data to the specified memory
2884mapped I/O address.
2885</p>
2886
2887<h5>Arguments:</h5>
2888
2889<p>
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2890The first argument is the value to write to the memory mapped I/O location.
2891The second argument is a pointer indicating the memory address to which the
2892data should be written.
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2893</p>
2894
2895<h5>Semantics:</h5>
2896
2897<p>
2898The '<tt>llvm.writeio</tt>' intrinsic writes <i>value</i> to the memory mapped
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2899I/O address specified by <i>pointer</i>. The value must be a
2900<a href="#t_firstclass">first class</a> type. However, certain architectures
Misha Brukman36c6bc12005-04-22 18:02:52 +0000[diff] [blame]2901may not support I/O on all first class types. For example, 32-bit processors
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2902may only support I/O on data types that are 32 bits or less.
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2903</p>
2904
2905<p>
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2906This intrinsic enforces an in-order memory model for llvm.readio and
2907llvm.writeio calls on machines that use dynamic scheduling. Dynamically
2908scheduled processors may execute loads and stores out of order, re-ordering at
2909run time accesses to memory mapped I/O registers. Using these intrinsics
2910ensures that accesses to memory mapped I/O registers occur in program order.
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2911</p>
2912
2913</div>
2914
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]2915<!-- ======================================================================= -->
2916<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2917 <a name="int_libc">Standard C Library Intrinsics</a>
2918</div>
2919
2920<div class="doc_text">
2921<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]2922LLVM provides intrinsics for a few important standard C library functions.
2923These intrinsics allow source-language front-ends to pass information about the
2924alignment of the pointer arguments to the code generator, providing opportunity
2925for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2926</p>
2927
2928</div>
2929
2930<!-- _______________________________________________________________________ -->
2931<div class="doc_subsubsection">
2932 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
2933</div>
2934
2935<div class="doc_text">
2936
2937<h5>Syntax:</h5>
2938<pre>
Reid Spencercf669d82005-04-26 20:41:16 +0000[diff] [blame]2939 declare void %llvm.memcpy(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
2940 uint &lt;len&gt;, uint &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2941</pre>
2942
2943<h5>Overview:</h5>
2944
2945<p>
2946The '<tt>llvm.memcpy</tt>' intrinsic copies a block of memory from the source
2947location to the destination location.
2948</p>
2949
2950<p>
2951Note that, unlike the standard libc function, the <tt>llvm.memcpy</tt> intrinsic
2952does not return a value, and takes an extra alignment argument.
2953</p>
2954
2955<h5>Arguments:</h5>
2956
2957<p>
2958The first argument is a pointer to the destination, the second is a pointer to
2959the source. The third argument is an (arbitrarily sized) integer argument
2960specifying the number of bytes to copy, and the fourth argument is the alignment
2961of the source and destination locations.
2962</p>
2963
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]2964<p>
2965If the call to this intrinisic has an alignment value that is not 0 or 1, then
2966the caller guarantees that the size of the copy is a multiple of the alignment
2967and that both the source and destination pointers are aligned to that boundary.
2968</p>
2969
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2970<h5>Semantics:</h5>
2971
2972<p>
2973The '<tt>llvm.memcpy</tt>' intrinsic copies a block of memory from the source
2974location to the destination location, which are not allowed to overlap. It
2975copies "len" bytes of memory over. If the argument is known to be aligned to
2976some boundary, this can be specified as the fourth argument, otherwise it should
2977be set to 0 or 1.
2978</p>
2979</div>
2980
2981
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]2982<!-- _______________________________________________________________________ -->
2983<div class="doc_subsubsection">
2984 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
2985</div>
2986
2987<div class="doc_text">
2988
2989<h5>Syntax:</h5>
2990<pre>
Reid Spencercf669d82005-04-26 20:41:16 +0000[diff] [blame]2991 declare void %llvm.memmove(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
2992 uint &lt;len&gt;, uint &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]2993</pre>
2994
2995<h5>Overview:</h5>
2996
2997<p>
2998The '<tt>llvm.memmove</tt>' intrinsic moves a block of memory from the source
2999location to the destination location. It is similar to the '<tt>llvm.memcpy</tt>'
3000intrinsic but allows the two memory locations to overlap.
3001</p>
3002
3003<p>
3004Note that, unlike the standard libc function, the <tt>llvm.memmove</tt> intrinsic
3005does not return a value, and takes an extra alignment argument.
3006</p>
3007
3008<h5>Arguments:</h5>
3009
3010<p>
3011The first argument is a pointer to the destination, the second is a pointer to
3012the source. The third argument is an (arbitrarily sized) integer argument
3013specifying the number of bytes to copy, and the fourth argument is the alignment
3014of the source and destination locations.
3015</p>
3016
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]3017<p>
3018If the call to this intrinisic has an alignment value that is not 0 or 1, then
3019the caller guarantees that the size of the copy is a multiple of the alignment
3020and that both the source and destination pointers are aligned to that boundary.
3021</p>
3022
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]3023<h5>Semantics:</h5>
3024
3025<p>
3026The '<tt>llvm.memmove</tt>' intrinsic copies a block of memory from the source
3027location to the destination location, which may overlap. It
3028copies "len" bytes of memory over. If the argument is known to be aligned to
3029some boundary, this can be specified as the fourth argument, otherwise it should
3030be set to 0 or 1.
3031</p>
3032</div>
3033
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3034
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3035<!-- _______________________________________________________________________ -->
3036<div class="doc_subsubsection">
3037 <a name="i_memset">'<tt>llvm.memset</tt>' Intrinsic</a>
3038</div>
3039
3040<div class="doc_text">
3041
3042<h5>Syntax:</h5>
3043<pre>
Reid Spencercf669d82005-04-26 20:41:16 +0000[diff] [blame]3044 declare void %llvm.memset(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
3045 uint &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3046</pre>
3047
3048<h5>Overview:</h5>
3049
3050<p>
3051The '<tt>llvm.memset</tt>' intrinsic fills a block of memory with a particular
3052byte value.
3053</p>
3054
3055<p>
3056Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
3057does not return a value, and takes an extra alignment argument.
3058</p>
3059
3060<h5>Arguments:</h5>
3061
3062<p>
3063The first argument is a pointer to the destination to fill, the second is the
3064byte value to fill it with, the third argument is an (arbitrarily sized) integer
3065argument specifying the number of bytes to fill, and the fourth argument is the
3066known alignment of destination location.
3067</p>
3068
3069<p>
3070If the call to this intrinisic has an alignment value that is not 0 or 1, then
3071the caller guarantees that the size of the copy is a multiple of the alignment
3072and that the destination pointer is aligned to that boundary.
3073</p>
3074
3075<h5>Semantics:</h5>
3076
3077<p>
3078The '<tt>llvm.memset</tt>' intrinsic fills "len" bytes of memory starting at the
3079destination location. If the argument is known to be aligned to some boundary,
3080this can be specified as the fourth argument, otherwise it should be set to 0 or
30811.
3082</p>
3083</div>
3084
3085
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]3086<!-- _______________________________________________________________________ -->
3087<div class="doc_subsubsection">
Alkis Evlogimenos0fa39232004-06-13 01:16:15 +0000[diff] [blame]3088 <a name="i_isunordered">'<tt>llvm.isunordered</tt>' Intrinsic</a>
3089</div>
3090
3091<div class="doc_text">
3092
3093<h5>Syntax:</h5>
3094<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]3095 declare bool %llvm.isunordered(&lt;float or double&gt; Val1, &lt;float or double&gt; Val2)
Alkis Evlogimenos0fa39232004-06-13 01:16:15 +0000[diff] [blame]3096</pre>
3097
3098<h5>Overview:</h5>
3099
3100<p>
3101The '<tt>llvm.isunordered</tt>' intrinsic returns true if either or both of the
3102specified floating point values is a NAN.
3103</p>
3104
3105<h5>Arguments:</h5>
3106
3107<p>
3108The arguments are floating point numbers of the same type.
3109</p>
3110
3111<h5>Semantics:</h5>
3112
3113<p>
3114If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
3115false.
3116</p>
3117</div>
3118
3119
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]3120<!-- ======================================================================= -->
3121<div class="doc_subsection">
3122 <a name="int_count">Bit Counting Intrinsics</a>
3123</div>
3124
3125<div class="doc_text">
3126<p>
3127LLVM provides intrinsics for a few important bit counting operations.
3128These allow efficient code generation for some algorithms.
3129</p>
3130
3131</div>
3132
3133<!-- _______________________________________________________________________ -->
3134<div class="doc_subsubsection">
3135 <a name="int_ctpop">'<tt>llvm.ctpop</tt>' Intrinsic</a>
3136</div>
3137
3138<div class="doc_text">
3139
3140<h5>Syntax:</h5>
3141<pre>
3142 declare int %llvm.ctpop(int &lt;src&gt;)
3143
3144</pre>
3145
3146<h5>Overview:</h5>
3147
3148<p>
3149The '<tt>llvm.ctpop</tt>' intrinsic counts the number of ones in a variable.
3150</p>
3151
3152<h5>Arguments:</h5>
3153
3154<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]3155The only argument is the value to be counted. The argument may be of any
3156integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]3157</p>
3158
3159<h5>Semantics:</h5>
3160
3161<p>
3162The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
3163</p>
3164</div>
3165
3166<!-- _______________________________________________________________________ -->
3167<div class="doc_subsubsection">
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]3168 <a name="int_ctlz">'<tt>llvm.ctlz</tt>' Intrinsic</a>
3169</div>
3170
3171<div class="doc_text">
3172
3173<h5>Syntax:</h5>
3174<pre>
3175 declare int %llvm.ctlz(int &lt;src&gt;)
3176
3177</pre>
3178
3179<h5>Overview:</h5>
3180
3181<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]3182The '<tt>llvm.ctlz</tt>' intrinsic counts the number of leading zeros in a
3183variable.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]3184</p>
3185
3186<h5>Arguments:</h5>
3187
3188<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]3189The only argument is the value to be counted. The argument may be of any
3190integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]3191</p>
3192
3193<h5>Semantics:</h5>
3194
3195<p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]3196The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
3197in a variable. If the src == 0 then the result is the size in bits of the type
3198of src. For example, <tt>llvm.cttz(int 2) = 30</tt>.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]3199</p>
3200</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]3201
3202
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]3203
3204<!-- _______________________________________________________________________ -->
3205<div class="doc_subsubsection">
3206 <a name="int_cttz">'<tt>llvm.cttz</tt>' Intrinsic</a>
3207</div>
3208
3209<div class="doc_text">
3210
3211<h5>Syntax:</h5>
3212<pre>
3213 declare int %llvm.cttz(int &lt;src&gt;)
3214
3215</pre>
3216
3217<h5>Overview:</h5>
3218
3219<p>
3220The '<tt>llvm.cttz</tt>' intrinsic counts the number of trailing zeros.
3221</p>
3222
3223<h5>Arguments:</h5>
3224
3225<p>
3226The only argument is the value to be counted. The argument may be of any
3227integer type. The return type must match the argument type.
3228</p>
3229
3230<h5>Semantics:</h5>
3231
3232<p>
3233The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
3234in a variable. If the src == 0 then the result is the size in bits of the type
3235of src. For example, <tt>llvm.cttz(2) = 1</tt>.
3236</p>
3237</div>
3238
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3239<!-- ======================================================================= -->
3240<div class="doc_subsection">
3241 <a name="int_debugger">Debugger Intrinsics</a>
3242</div>
3243
3244<div class="doc_text">
3245<p>
3246The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
3247are described in the <a
3248href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
3249Debugging</a> document.
3250</p>
3251</div>
3252
3253
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3254<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3255<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]3256<address>
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3261
3262 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
3263 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
3264 Last modified: $Date$
3265</address>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3266</body>
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