Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1 | <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" |
| 2 | "http://www.w3.org/TR/html4/strict.dtd"> |
| 3 | <html> |
| 4 | <head> |
| 5 | <title>LLVM Assembly Language Reference Manual</title> |
| 6 | <link rel="stylesheet" href="llvm.css" type="text/css"> |
| 7 | </head> |
| 8 | <body> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 9 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 10 | <div class="doc_title"> |
| 11 | LLVM Language Reference Manual |
| 12 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 13 | |
| 14 | <ol> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 15 | <li><a href="#abstract">Abstract</a></li> |
| 16 | <li><a href="#introduction">Introduction</a></li> |
| 17 | <li><a href="#identifiers">Identifiers</a></li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 18 | <li><a href="#typesystem">Type System</a> |
| 19 | <ol> |
| 20 | <li><a href="#t_primitive">Primitive Types</a> |
| 21 | <ol> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 22 | <li><a href="#t_classifications">Type Classifications</a></li> |
| 23 | </ol></li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 24 | <li><a href="#t_derived">Derived Types</a> |
| 25 | <ol> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 26 | <li><a href="#t_array" >Array Type</a></li> |
| 27 | <li><a href="#t_function">Function Type</a></li> |
| 28 | <li><a href="#t_pointer">Pointer Type</a></li> |
| 29 | <li><a href="#t_struct" >Structure Type</a></li> |
Chris Lattner | 690d99b | 2002-08-29 18:33:48 +0000 | [diff] [blame] | 30 | <!-- <li><a href="#t_packed" >Packed Type</a> --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 31 | </ol></li> |
| 32 | </ol></li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 33 | <li><a href="#highlevel">High Level Structure</a> |
| 34 | <ol> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 35 | <li><a href="#modulestructure">Module Structure</a></li> |
| 36 | <li><a href="#globalvars">Global Variables</a></li> |
| 37 | <li><a href="#functionstructure">Function Structure</a></li> |
| 38 | </ol></li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 39 | <li><a href="#instref">Instruction Reference</a> |
| 40 | <ol> |
| 41 | <li><a href="#terminators">Terminator Instructions</a> |
| 42 | <ol> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 43 | <li><a href="#i_ret" >'<tt>ret</tt>' Instruction</a></li> |
| 44 | <li><a href="#i_br" >'<tt>br</tt>' Instruction</a></li> |
| 45 | <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li> |
| 46 | <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li> |
| 47 | <li><a href="#i_unwind" >'<tt>unwind</tt>' Instruction</a></li> |
| 48 | </ol></li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 49 | <li><a href="#binaryops">Binary Operations</a> |
| 50 | <ol> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 51 | <li><a href="#i_add" >'<tt>add</tt>' Instruction</a></li> |
| 52 | <li><a href="#i_sub" >'<tt>sub</tt>' Instruction</a></li> |
| 53 | <li><a href="#i_mul" >'<tt>mul</tt>' Instruction</a></li> |
| 54 | <li><a href="#i_div" >'<tt>div</tt>' Instruction</a></li> |
| 55 | <li><a href="#i_rem" >'<tt>rem</tt>' Instruction</a></li> |
| 56 | <li><a href="#i_setcc">'<tt>set<i>cc</i></tt>' Instructions</a></li> |
| 57 | </ol></li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 58 | <li><a href="#bitwiseops">Bitwise Binary Operations</a> |
| 59 | <ol> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 60 | <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li> |
| 61 | <li><a href="#i_or" >'<tt>or</tt>' Instruction</a></li> |
| 62 | <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li> |
| 63 | <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li> |
| 64 | <li><a href="#i_shr">'<tt>shr</tt>' Instruction</a></li> |
| 65 | </ol></li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 66 | <li><a href="#memoryops">Memory Access Operations</a> |
| 67 | <ol> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 68 | <li><a href="#i_malloc" >'<tt>malloc</tt>' Instruction</a></li> |
| 69 | <li><a href="#i_free" >'<tt>free</tt>' Instruction</a></li> |
| 70 | <li><a href="#i_alloca" >'<tt>alloca</tt>' Instruction</a></li> |
| 71 | <li><a href="#i_load" >'<tt>load</tt>' Instruction</a></li> |
| 72 | <li><a href="#i_store" >'<tt>store</tt>' Instruction</a></li> |
| 73 | <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li> |
| 74 | </ol></li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 75 | <li><a href="#otherops">Other Operations</a> |
| 76 | <ol> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 77 | <li><a href="#i_phi" >'<tt>phi</tt>' Instruction</a></li> |
| 78 | <li><a href="#i_cast">'<tt>cast .. to</tt>' Instruction</a></li> |
| 79 | <li><a href="#i_call" >'<tt>call</tt>' Instruction</a></li> |
| 80 | <li><a href="#i_vanext">'<tt>vanext</tt>' Instruction</a></li> |
| 81 | <li><a href="#i_vaarg" >'<tt>vaarg</tt>' Instruction</a></li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 82 | </ol> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 83 | </ol> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 84 | <li><a href="#intrinsics">Intrinsic Functions</a> |
| 85 | <ol> |
| 86 | <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a> |
| 87 | <ol> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 88 | <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li> |
| 89 | <li><a href="#i_va_end" >'<tt>llvm.va_end</tt>' Intrinsic</a></li> |
| 90 | <li><a href="#i_va_copy" >'<tt>llvm.va_copy</tt>' Intrinsic</a></li> |
| 91 | </ol></li> |
| 92 | </ol></li> |
Chris Lattner | d816bcf | 2002-08-30 21:50:21 +0000 | [diff] [blame] | 93 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 94 | </ol> |
| 95 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 96 | <div class="doc_text"> |
| 97 | <p><b>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a> and <A href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></b><p> |
| 98 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 99 | |
| 100 | <!-- *********************************************************************** --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 101 | <div class="doc_section"> |
| 102 | <a name="abstract">Abstract |
| 103 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 104 | <!-- *********************************************************************** --> |
| 105 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 106 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 107 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 108 | <p>This document is a reference manual for the LLVM assembly language. LLVM is |
| 109 | an SSA based representation that provides type safety, low-level operations, |
| 110 | flexibility, and the capability of representing 'all' high-level languages |
| 111 | cleanly. It is the common code representation used throughout all phases of the |
| 112 | LLVM compilation strategy.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 113 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 114 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 115 | |
| 116 | <!-- *********************************************************************** --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 117 | <div class="doc_section"> |
| 118 | <a name="introduction">Introduction</a> |
| 119 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 120 | <!-- *********************************************************************** --> |
| 121 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 122 | <div class="doc_text"> |
| 123 | |
| 124 | <p>The LLVM code representation is designed to be used in three different forms: |
| 125 | as an in-memory compiler IR, as an on-disk bytecode representation (suitable for |
Chris Lattner | fde246a | 2003-09-02 23:38:41 +0000 | [diff] [blame] | 126 | fast loading by a Just-In-Time compiler), and as a human readable assembly |
| 127 | language representation. This allows LLVM to provide a powerful intermediate |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 128 | representation for efficient compiler transformations and analysis, while |
| 129 | providing a natural means to debug and visualize the transformations. The three |
| 130 | different forms of LLVM are all equivalent. This document describes the human |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 131 | readable representation and notation.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 132 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 133 | <p>The LLVM representation aims to be a light-weight and low-level while being |
Chris Lattner | b7c6c2a | 2002-06-25 20:20:08 +0000 | [diff] [blame] | 134 | expressive, typed, and extensible at the same time. It aims to be a "universal |
Chris Lattner | fde246a | 2003-09-02 23:38:41 +0000 | [diff] [blame] | 135 | IR" of sorts, by being at a low enough level that high-level ideas may be |
Chris Lattner | b7c6c2a | 2002-06-25 20:20:08 +0000 | [diff] [blame] | 136 | cleanly mapped to it (similar to how microprocessors are "universal IR's", |
| 137 | allowing many source languages to be mapped to them). By providing type |
| 138 | information, LLVM can be used as the target of optimizations: for example, |
| 139 | through pointer analysis, it can be proven that a C automatic variable is never |
| 140 | accessed outside of the current function... allowing it to be promoted to a |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 141 | simple SSA value instead of a memory location.</p> |
| 142 | |
| 143 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 144 | |
| 145 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 146 | <div class="doc_subsubsection"> |
| 147 | <a name="wellformed">Well-Formedness</a> |
| 148 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 149 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 150 | <div class="doc_text"> |
| 151 | |
| 152 | <p>It is important to note that this document describes 'well formed' LLVM |
| 153 | assembly language. There is a difference between what the parser accepts and |
| 154 | what is considered 'well formed'. For example, the following instruction is |
| 155 | syntactically okay, but not well formed:</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 156 | |
| 157 | <pre> |
| 158 | %x = <a href="#i_add">add</a> int 1, %x |
| 159 | </pre> |
| 160 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 161 | <p>...because the definition of <tt>%x</tt> does not dominate all of its uses. |
| 162 | The LLVM infrastructure provides a verification pass that may be used to verify |
| 163 | that an LLVM module is well formed. This pass is automatically run by the |
| 164 | parser after parsing input assembly, and by the optimizer before it outputs |
| 165 | bytecode. The violations pointed out by the verifier pass indicate bugs in |
| 166 | transformation passes or input to the parser.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 167 | |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 168 | <!-- Describe the typesetting conventions here. --> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 169 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 170 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 171 | |
| 172 | <!-- *********************************************************************** --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 173 | <div class="doc_section"> |
| 174 | <a name="identifiers">Identifiers</a> |
| 175 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 176 | <!-- *********************************************************************** --> |
| 177 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 178 | <div class="doc_text"> |
| 179 | |
| 180 | <p>LLVM uses three different forms of identifiers, for different purposes:</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 181 | |
| 182 | <ol> |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 183 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 184 | <li>Numeric constants are represented as you would expect: 12, -3 123.421, |
| 185 | etc. Floating point constants have an optional hexidecimal notation.</li> |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 186 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 187 | <li>Named values are represented as a string of characters with a '%' prefix. |
| 188 | For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual |
| 189 | regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. |
| 190 | Identifiers which require other characters in their names can be surrounded |
| 191 | with quotes. In this way, anything except a <tt>"</tt> character can be used |
| 192 | in a name.</li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 193 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 194 | <li>Unnamed values are represented as an unsigned numeric value with a '%' |
| 195 | prefix. For example, %12, %2, %44.</li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 196 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 197 | </ol> |
| 198 | |
| 199 | <p>LLVM requires the values start with a '%' sign for two reasons: Compilers |
| 200 | don't need to worry about name clashes with reserved words, and the set of |
| 201 | reserved words may be expanded in the future without penalty. Additionally, |
| 202 | unnamed identifiers allow a compiler to quickly come up with a temporary |
| 203 | variable without having to avoid symbol table conflicts.</p> |
| 204 | |
| 205 | <p>Reserved words in LLVM are very similar to reserved words in other languages. |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 206 | There are keywords for different opcodes ('<tt><a href="#i_add">add</a></tt>', |
| 207 | '<tt><a href="#i_cast">cast</a></tt>', '<tt><a href="#i_ret">ret</a></tt>', |
| 208 | etc...), for primitive type names ('<tt><a href="#t_void">void</a></tt>', |
| 209 | '<tt><a href="#t_uint">uint</a></tt>', etc...), and others. These reserved |
| 210 | words cannot conflict with variable names, because none of them start with a '%' |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 211 | character.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 212 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 213 | <p>Here is an example of LLVM code to multiply the integer variable |
| 214 | '<tt>%X</tt>' by 8:</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 215 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 216 | <p>The easy way:</p> |
| 217 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 218 | <pre> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 219 | %result = <a href="#i_mul">mul</a> uint %X, 8 |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 220 | </pre> |
| 221 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 222 | <p>After strength reduction:</p> |
| 223 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 224 | <pre> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 225 | %result = <a href="#i_shl">shl</a> uint %X, ubyte 3 |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 226 | </pre> |
| 227 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 228 | <p>And the hard way:</p> |
| 229 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 230 | <pre> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 231 | <a href="#i_add">add</a> uint %X, %X <i>; yields {uint}:%0</i> |
| 232 | <a href="#i_add">add</a> uint %0, %0 <i>; yields {uint}:%1</i> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 233 | %result = <a href="#i_add">add</a> uint %1, %1 |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 234 | </pre> |
| 235 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 236 | <p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important |
| 237 | lexical features of LLVM:</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 238 | |
| 239 | <ol> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 240 | <li>Comments are delimited with a '<tt>;</tt>' and go until the end of |
| 241 | line.</li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 242 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 243 | <li>Unnamed temporaries are created when the result of a computation is not |
| 244 | assigned to a named value.</li> |
| 245 | |
| 246 | <li>Unnamed temporaries are numbered sequentially</li> |
| 247 | </ol> |
| 248 | |
| 249 | <p>...and it also show a convention that we follow in this document. When |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 250 | demonstrating instructions, we will follow an instruction with a comment that |
| 251 | defines the type and name of value produced. Comments are shown in italic |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 252 | text.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 253 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 254 | <p>The one non-intuitive notation for constants is the optional hexidecimal form |
| 255 | of floating point constants. For example, the form '<tt>double |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 256 | 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double |
| 257 | 4.5e+15</tt>' which is also supported by the parser. The only time hexadecimal |
| 258 | floating point constants are useful (and the only time that they are generated |
| 259 | by the disassembler) is when an FP constant has to be emitted that is not |
| 260 | representable as a decimal floating point number exactly. For example, NaN's, |
| 261 | infinities, and other special cases are represented in their IEEE hexadecimal |
| 262 | format so that assembly and disassembly do not cause any bits to change in the |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 263 | constants.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 264 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 265 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 266 | |
| 267 | <!-- *********************************************************************** --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 268 | <div class="doc_section"> |
| 269 | <a name="typesystem">Type System</a> |
| 270 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 271 | <!-- *********************************************************************** --> |
| 272 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 273 | <div class="doc_text"> |
| 274 | |
| 275 | <p>The LLVM type system is one of the most important features of the |
| 276 | intermediate representation. Being typed enables a number of optimizations to |
| 277 | be performed on the IR directly, without having to do extra analyses on the side |
| 278 | before the transformation. A strong type system makes it easier to read the |
| 279 | generated code and enables novel analyses and transformations that are not |
| 280 | feasible to perform on normal three address code representations.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 281 | |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 282 | <!-- The written form for the type system was heavily influenced by the |
| 283 | syntactic problems with types in the C language<sup><a |
| 284 | href="#rw_stroustrup">1</a></sup>.<p> --> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 285 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 286 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 287 | |
| 288 | <!-- ======================================================================= --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 289 | <div class="doc_subsection"> |
| 290 | <a name="t_primitive">Primitive Types</a> |
| 291 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 292 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 293 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 294 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 295 | <p>The primitive types are the fundemental building blocks of the LLVM system. |
| 296 | The current set of primitive types are as follows:</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 297 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 298 | <p> |
| 299 | <table border="0" align="center"> |
| 300 | <tr> |
| 301 | <td> |
| 302 | |
| 303 | <table border="1" cellspacing="0" cellpadding="4" align="center"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 304 | <tr><td><tt>void</tt></td> <td>No value</td></tr> |
| 305 | <tr><td><tt>ubyte</tt></td> <td>Unsigned 8 bit value</td></tr> |
| 306 | <tr><td><tt>ushort</tt></td><td>Unsigned 16 bit value</td></tr> |
| 307 | <tr><td><tt>uint</tt></td> <td>Unsigned 32 bit value</td></tr> |
| 308 | <tr><td><tt>ulong</tt></td> <td>Unsigned 64 bit value</td></tr> |
| 309 | <tr><td><tt>float</tt></td> <td>32 bit floating point value</td></tr> |
| 310 | <tr><td><tt>label</tt></td> <td>Branch destination</td></tr> |
| 311 | </table> |
| 312 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 313 | </td><td valign=top> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 314 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 315 | <table border="1" cellspacing="0" cellpadding="4" align=center"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 316 | <tr><td><tt>bool</tt></td> <td>True or False value</td></tr> |
| 317 | <tr><td><tt>sbyte</tt></td> <td>Signed 8 bit value</td></tr> |
| 318 | <tr><td><tt>short</tt></td> <td>Signed 16 bit value</td></tr> |
| 319 | <tr><td><tt>int</tt></td> <td>Signed 32 bit value</td></tr> |
| 320 | <tr><td><tt>long</tt></td> <td>Signed 64 bit value</td></tr> |
| 321 | <tr><td><tt>double</tt></td><td>64 bit floating point value</td></tr> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 322 | </table> |
| 323 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 324 | </td> |
| 325 | </tr> |
| 326 | </table> |
| 327 | </p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 328 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 329 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 330 | |
| 331 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 332 | <div class="doc_subsubsection"> |
| 333 | <a name="t_classifications">Type Classifications</a> |
| 334 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 335 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 336 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 337 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 338 | <p>These different primitive types fall into a few useful classifications:</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 339 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 340 | <p> |
| 341 | <table border="1" cellspacing="0" cellpadding="4" align="center"> |
| 342 | <tr> |
| 343 | <td><a name="t_signed">signed</td> |
| 344 | <td><tt>sbyte, short, int, long, float, double</tt></td> |
| 345 | </tr> |
| 346 | <tr> |
| 347 | <td><a name="t_unsigned">unsigned</td> |
| 348 | <td><tt>ubyte, ushort, uint, ulong</tt></td> |
| 349 | </tr> |
| 350 | <tr> |
| 351 | <td><a name="t_integer">integer</td> |
| 352 | <td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td> |
| 353 | </tr> |
| 354 | <tr> |
| 355 | <td><a name="t_integral">integral</td> |
| 356 | <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td> |
| 357 | </tr> |
| 358 | <tr> |
| 359 | <td><a name="t_floating">floating point</td> |
| 360 | <td><tt>float, double</tt></td> |
| 361 | </tr> |
| 362 | <tr> |
| 363 | <td><a name="t_firstclass">first class</td> |
| 364 | <td><tt>bool, ubyte, sbyte, ushort, short,<br> |
| 365 | uint, int, ulong, long, float, double, |
| 366 | <a href="#t_pointer">pointer</a></tt></td> |
| 367 | </tr> |
| 368 | </table> |
| 369 | </p> |
| 370 | |
| 371 | <p>The <a href="#t_firstclass">first class</a> types are perhaps the most |
Chris Lattner | 478921b | 2003-10-30 01:31:37 +0000 | [diff] [blame] | 372 | important. Values of these types are the only ones which can be produced by |
| 373 | instructions, passed as arguments, or used as operands to instructions. This |
| 374 | means that all structures and arrays must be manipulated either by pointer or by |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 375 | component.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 376 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 377 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 378 | |
| 379 | <!-- ======================================================================= --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 380 | <div class="doc_subsection"> |
| 381 | <a name="t_derived">Derived Types</a> |
| 382 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 383 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 384 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 385 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 386 | <p>The real power in LLVM comes from the derived types in the system. This is |
| 387 | what allows a programmer to represent arrays, functions, pointers, and other |
| 388 | useful types. Note that these derived types may be recursive: For example, it |
| 389 | is possible to have a two dimensional array.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 390 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 391 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 392 | |
| 393 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 394 | <div class="doc_subsubsection"> |
| 395 | <a name="t_array">Array Type</a> |
| 396 | </div> |
| 397 | |
| 398 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 399 | |
| 400 | <h5>Overview:</h5> |
| 401 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 402 | <p>The array type is a very simple derived type that arranges elements |
| 403 | sequentially in memory. The array type requires a size (number of elements) and |
| 404 | an underlying data type.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 405 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 406 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 407 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 408 | <pre> |
| 409 | [<# elements> x <elementtype>] |
| 410 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 411 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 412 | <p>The number of elements is a constant integer value, elementtype may be any |
| 413 | type with a size.</p> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 414 | |
| 415 | <h5>Examples:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 416 | |
| 417 | <p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 418 | <tt>[40 x int ]</tt>: Array of 40 integer values.<br> |
| 419 | <tt>[41 x int ]</tt>: Array of 41 integer values.<br> |
| 420 | <tt>[40 x uint]</tt>: Array of 40 unsigned integer values.<p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 421 | </p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 422 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 423 | <p>Here are some examples of multidimensional arrays:</p> |
| 424 | |
| 425 | <p> |
| 426 | <table border="0" cellpadding="0" cellspacing="0"> |
| 427 | <tr> |
| 428 | <td><tt>[3 x [4 x int]]</tt></td> |
| 429 | <td>: 3x4 array integer values.</td> |
| 430 | </tr> |
| 431 | <tr> |
| 432 | <td><tt>[12 x [10 x float]]</tt></td> |
| 433 | <td>: 12x10 array of single precision floating point values.</td> |
| 434 | </tr> |
| 435 | <tr> |
| 436 | <td><tt>[2 x [3 x [4 x uint]]]</tt></td> |
| 437 | <td>: 2x3x4 array of unsigned integer values.</td> |
| 438 | </tr> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 439 | </table> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 440 | </p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 441 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 442 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 443 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 444 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 445 | <div class="doc_subsubsection"> |
| 446 | <a name="t_function">Function Type</a> |
| 447 | </div> |
| 448 | |
| 449 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 450 | |
| 451 | <h5>Overview:</h5> |
| 452 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 453 | <p>The function type can be thought of as a function signature. It consists of |
| 454 | a return type and a list of formal parameter types. Function types are usually |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 455 | used when to build virtual function tables (which are structures of pointers to |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 456 | functions), for indirect function calls, and when defining a function.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 457 | |
| 458 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 459 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 460 | <pre> |
| 461 | <returntype> (<parameter list>) |
| 462 | </pre> |
| 463 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 464 | <p>Where '<tt><parameter list></tt>' is a comma-separated list of type |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 465 | specifiers. Optionally, the parameter list may include a type <tt>...</tt>, |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 466 | which indicates that the function takes a variable number of arguments. |
| 467 | Variable argument functions can access their arguments with the <a |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 468 | href="#int_varargs">variable argument handling intrinsic</a> functions.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 469 | |
| 470 | <h5>Examples:</h5> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 471 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 472 | <p> |
| 473 | <table border="0" cellpadding="0" cellspacing="0"> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 474 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 475 | <tr> |
| 476 | <td><tt>int (int)</tt></td> |
| 477 | <td>: function taking an <tt>int</tt>, returning an <tt>int</tt></td> |
| 478 | </tr> |
| 479 | <tr> |
| 480 | <td><tt>float (int, int *) *</tt></td> |
| 481 | <td>: <a href="#t_pointer">Pointer</a> to a function that takes an |
| 482 | <tt>int</tt> and a <a href="#t_pointer">pointer</a> to <tt>int</tt>, |
| 483 | returning <tt>float</tt>.</td> |
| 484 | </tr> |
| 485 | <tr> |
| 486 | <td><tt>int (sbyte *, ...)</tt></td> |
| 487 | <td>: A vararg function that takes at least one <a |
| 488 | href="#t_pointer">pointer</a> to <tt>sbyte</tt> (signed char in C), which |
| 489 | returns an integer. This is the signature for <tt>printf</tt> in |
| 490 | LLVM.</td> |
| 491 | </tr> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 492 | </table> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 493 | </p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 494 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 495 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 496 | |
| 497 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 498 | <div class="doc_subsubsection"> |
| 499 | <a name="t_struct">Structure Type</a> |
| 500 | </div> |
| 501 | |
| 502 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 503 | |
| 504 | <h5>Overview:</h5> |
| 505 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 506 | <p>The structure type is used to represent a collection of data members together |
| 507 | in memory. The packing of the field types is defined to match the ABI of the |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 508 | underlying processor. The elements of a structure may be any type that has a |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 509 | size.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 510 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 511 | <p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and |
| 512 | '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with the |
| 513 | '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 514 | |
| 515 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 516 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 517 | <pre> |
| 518 | { <type list> } |
| 519 | </pre> |
| 520 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 521 | <h5>Examples:</h5> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 522 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 523 | <p> |
| 524 | <table border="0" cellpadding="0" cellspacing="0"> |
| 525 | <tr> |
| 526 | <td><tt>{ int, int, int }</tt></td> |
| 527 | <td>: a triple of three <tt>int</tt> values</td> |
| 528 | </tr> |
| 529 | <tr> |
| 530 | <td><tt>{ float, int (int) * }</tt></td> |
| 531 | <td>: A pair, where the first element is a <tt>float</tt> and the second |
| 532 | element is a <a href="#t_pointer">pointer</a> to a <a |
| 533 | href="t_function">function</a> that takes an <tt>int</tt>, returning an |
| 534 | <tt>int</tt>.</td> |
| 535 | </tr> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 536 | </table> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 537 | </p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 538 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 539 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 540 | |
| 541 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 542 | <div class="doc_subsubsection"> |
| 543 | <a name="t_pointer">Pointer Type</a> |
| 544 | </div> |
| 545 | |
| 546 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 547 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 548 | <h5>Overview:</h5> |
| 549 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 550 | <p>As in many languages, the pointer type represents a pointer or reference to |
| 551 | another object, which must live in memory.</p> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 552 | |
| 553 | <h5>Syntax:</h5> |
| 554 | <pre> |
| 555 | <type> * |
| 556 | </pre> |
| 557 | |
| 558 | <h5>Examples:</h5> |
| 559 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 560 | <p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 561 | <table border="0" cellpadding="0" cellspacing="0"> |
| 562 | <tr> |
| 563 | <td><tt>[4x int]*</tt></td> |
| 564 | <td>: <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of four |
| 565 | <tt>int</tt> values</td> |
| 566 | </tr> |
| 567 | <tr> |
| 568 | <td><tt>int (int *) *</tt></td> |
| 569 | <td>: A <a href="#t_pointer">pointer</a> to a <a |
| 570 | href="t_function">function</a> that takes an <tt>int</tt>, returning an |
| 571 | <tt>int</tt>.</td> |
| 572 | </tr> |
| 573 | </table> |
| 574 | </p> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 575 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 576 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 577 | |
| 578 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 579 | <!-- |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 580 | <div class="doc_subsubsection"> |
| 581 | <a name="t_packed">Packed Type</a> |
| 582 | </div> |
| 583 | |
| 584 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 585 | |
| 586 | Mention/decide that packed types work with saturation or not. Maybe have a packed+saturated type in addition to just a packed type.<p> |
| 587 | |
| 588 | Packed types should be 'nonsaturated' because standard data types are not saturated. Maybe have a saturated packed type?<p> |
| 589 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 590 | </div> |
| 591 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 592 | --> |
| 593 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 594 | |
| 595 | <!-- *********************************************************************** --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 596 | <div class="doc_section"> |
| 597 | <a name="highlevel">High Level Structure</a> |
| 598 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 599 | <!-- *********************************************************************** --> |
| 600 | |
| 601 | |
| 602 | <!-- ======================================================================= --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 603 | <div class="doc_subsection"> |
| 604 | <a name="modulestructure">Module Structure</a> |
| 605 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 606 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 607 | <div class="doc_text"> |
| 608 | |
| 609 | <p>LLVM programs are composed of "Module"s, each of which is a translation unit |
| 610 | of the input programs. Each module consists of functions, global variables, and |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 611 | symbol table entries. Modules may be combined together with the LLVM linker, |
| 612 | which merges function (and global variable) definitions, resolves forward |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 613 | declarations, and merges symbol table entries. Here is an example of the "hello |
| 614 | world" module:</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 615 | |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 616 | <pre> |
| 617 | <i>; Declare the string constant as a global constant...</i> |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 618 | <a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x sbyte]</a> c"hello world\0A\00" <i>; [13 x sbyte]*</i> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 619 | |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 620 | <i>; External declaration of the puts function</i> |
| 621 | <a href="#functionstructure">declare</a> int %puts(sbyte*) <i>; int(sbyte*)* </i> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 622 | |
| 623 | <i>; Definition of main function</i> |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 624 | int %main() { <i>; int()* </i> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 625 | <i>; Convert [13x sbyte]* to sbyte *...</i> |
Chris Lattner | 3dfa10b | 2002-12-13 06:01:21 +0000 | [diff] [blame] | 626 | %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x sbyte]* %.LC0, long 0, long 0 <i>; sbyte*</i> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 627 | |
| 628 | <i>; Call puts function to write out the string to stdout...</i> |
| 629 | <a href="#i_call">call</a> int %puts(sbyte* %cast210) <i>; int</i> |
| 630 | <a href="#i_ret">ret</a> int 0 |
| 631 | } |
| 632 | </pre> |
| 633 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 634 | <p>This example is made up of a <a href="#globalvars">global variable</a> named |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 635 | "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and a |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 636 | <a href="#functionstructure">function definition</a> for "<tt>main</tt>".</p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 637 | |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 638 | <a name="linkage"> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 639 | In general, a module is made up of a list of global values, where both functions |
| 640 | and global variables are global values. Global values are represented by a |
| 641 | pointer to a memory location (in this case, a pointer to an array of char, and a |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 642 | pointer to a function), and have one of the following linkage types:<p> |
| 643 | |
| 644 | <dl> |
| 645 | <a name="linkage_internal"> |
| 646 | <dt><tt><b>internal</b></tt> |
| 647 | |
| 648 | <dd>Global values with internal linkage are only directly accessible by objects |
| 649 | in the current module. In particular, linking code into a module with an |
| 650 | internal global value may cause the internal to be renamed as necessary to avoid |
| 651 | collisions. Because the symbol is internal to the module, all references can be |
| 652 | updated. This corresponds to the notion of the '<tt>static</tt>' keyword in C, |
| 653 | or the idea of "anonymous namespaces" in C++.<p> |
| 654 | |
| 655 | <a name="linkage_linkonce"> |
| 656 | <dt><tt><b>linkonce</b></tt>: |
| 657 | |
| 658 | <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with |
| 659 | the twist that linking together two modules defining the same <tt>linkonce</tt> |
| 660 | globals will cause one of the globals to be discarded. This is typically used |
Chris Lattner | 25839f0 | 2003-10-10 05:01:39 +0000 | [diff] [blame] | 661 | to implement inline functions. Unreferenced <tt>linkonce</tt> globals are |
| 662 | allowed to be discarded.<p> |
| 663 | |
| 664 | <a name="linkage_weak"> |
| 665 | <dt><tt><b>weak</b></tt>: |
| 666 | |
| 667 | <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage, |
| 668 | except that unreferenced <tt>weak</tt> globals may not be discarded. This is |
| 669 | used to implement constructs in C such as "<tt>int X;</tt>" at global scope.<p> |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 670 | |
| 671 | <a name="linkage_appending"> |
| 672 | <dt><tt><b>appending</b></tt>: |
| 673 | |
| 674 | <dd>"<tt>appending</tt>" linkage may only applied to global variables of pointer |
| 675 | to array type. When two global variables with appending linkage are linked |
| 676 | together, the two global arrays are appended together. This is the LLVM, |
| 677 | typesafe, equivalent of having the system linker append together "sections" with |
| 678 | identical names when .o files are linked.<p> |
| 679 | |
| 680 | <a name="linkage_external"> |
| 681 | <dt><tt><b>externally visible</b></tt>: |
| 682 | |
| 683 | <dd>If none of the above identifiers are used, the global is externally visible, |
| 684 | meaning that it participates in linkage and can be used to resolve external |
| 685 | symbol references.<p> |
| 686 | |
| 687 | </dl><p> |
| 688 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 689 | <p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 690 | another module defined a "<tt>.LC0</tt>" variable and was linked with this one, |
| 691 | one of the two would be renamed, preventing a collision. Since "<tt>main</tt>" |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 692 | and "<tt>puts</tt>" are external (i.e., lacking any linkage declarations), they |
| 693 | are accessible outside of the current module. It is illegal for a function |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 694 | <i>declaration</i> to have any linkage type other than "externally visible".</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 695 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 696 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 697 | |
| 698 | <!-- ======================================================================= --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 699 | <div class="doc_subsection"> |
| 700 | <a name="globalvars">Global Variables</a> |
| 701 | </div> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 702 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 703 | <div class="doc_text"> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 704 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 705 | <p>Global variables define regions of memory allocated at compilation time |
| 706 | instead of run-time. Global variables may optionally be initialized. A |
| 707 | variable may be defined as a global "constant", which indicates that the |
| 708 | contents of the variable will never be modified (opening options for |
| 709 | optimization). Constants must always have an initial value.</p> |
| 710 | |
| 711 | <p>As SSA values, global variables define pointer values that are in scope |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 712 | (i.e. they dominate) for all basic blocks in the program. Global variables |
| 713 | always define a pointer to their "content" type because they describe a region |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 714 | of memory, and all memory objects in LLVM are accessed through pointers.</p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 715 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 716 | </div> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 717 | |
| 718 | <!-- ======================================================================= --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 719 | <div class="doc_subsection"> |
| 720 | <a name="functionstructure">Functions</a> |
| 721 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 722 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 723 | <div class="doc_text"> |
| 724 | |
| 725 | <p>LLVM functions definitions are composed of a (possibly empty) argument list, |
| 726 | an opening curly brace, a list of basic blocks, and a closing curly brace. LLVM |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 727 | function declarations are defined with the "<tt>declare</tt>" keyword, a |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 728 | function name and a function signature.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 729 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 730 | <p>A function definition contains a list of basic blocks, forming the CFG for |
| 731 | the function. Each basic block may optionally start with a label (giving the |
| 732 | basic block a symbol table entry), contains a list of instructions, and ends |
| 733 | with a <a href="#terminators">terminator</a> instruction (such as a branch or |
| 734 | function return).</p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 735 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 736 | <p>The first basic block in program is special in two ways: it is immediately |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 737 | executed on entrance to the function, and it is not allowed to have predecessor |
| 738 | basic blocks (i.e. there can not be any branches to the entry block of a |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 739 | function). Because the block can have no predecessors, it also cannot have any |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 740 | <a href="#i_phi">PHI nodes</a>.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 741 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 742 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 743 | |
| 744 | <!-- *********************************************************************** --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 745 | <div class="doc_section"> |
| 746 | <a name="instref">Instruction Reference</a> |
| 747 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 748 | <!-- *********************************************************************** --> |
| 749 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 750 | <div class="doc_text"> |
| 751 | |
| 752 | <p>The LLVM instruction set consists of several different classifications of |
Chris Lattner | e489aa5 | 2002-08-14 17:55:59 +0000 | [diff] [blame] | 753 | instructions: <a href="#terminators">terminator instructions</a>, <a |
| 754 | href="#binaryops">binary instructions</a>, <a href="#memoryops">memory |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 755 | instructions</a>, and <a href="#otherops">other instructions</a>.</p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 756 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 757 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 758 | |
| 759 | <!-- ======================================================================= --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 760 | <div class="doc_subsection"> |
| 761 | <a name="terminators">Terminator Instructions</a> |
| 762 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 763 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 764 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 765 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 766 | <p>As mentioned <a href="#functionstructure">previously</a>, every basic block |
| 767 | in a program ends with a "Terminator" instruction, which indicates which block |
| 768 | should be executed after the current block is finished. These terminator |
| 769 | instructions typically yield a '<tt>void</tt>' value: they produce control flow, |
| 770 | not values (the one exception being the '<a |
| 771 | href="#i_invoke"><tt>invoke</tt></a>' instruction).</p> |
| 772 | |
| 773 | <p>There are five different terminator instructions: the '<a |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 774 | href="#i_ret"><tt>ret</tt></a>' instruction, the '<a |
| 775 | href="#i_br"><tt>br</tt></a>' instruction, the '<a |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 776 | href="#i_switch"><tt>switch</tt></a>' instruction, the '<a |
| 777 | href="#i_invoke"><tt>invoke</tt></a>' instruction, and the '<a |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 778 | href="#i_unwind"><tt>unwind</tt></a>' instruction.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 779 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 780 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 781 | |
| 782 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 783 | <div class="doc_subsubsection"> |
| 784 | <a name="i_ret">'<tt>ret</tt>' Instruction</a> |
| 785 | </div> |
| 786 | |
| 787 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 788 | |
| 789 | <h5>Syntax:</h5> |
| 790 | <pre> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 791 | ret <type> <value> <i>; Return a value from a non-void function</i> |
| 792 | ret void <i>; Return from void function</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 793 | </pre> |
| 794 | |
| 795 | <h5>Overview:</h5> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 796 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 797 | <p>The '<tt>ret</tt>' instruction is used to return control flow (and a value) |
| 798 | from a function, back to the caller.</p> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 799 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 800 | <p>There are two forms of the '<tt>ret</tt>' instructruction: one that returns a |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 801 | value and then causes control flow, and one that just causes control flow to |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 802 | occur.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 803 | |
| 804 | <h5>Arguments:</h5> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 805 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 806 | <p>The '<tt>ret</tt>' instruction may return any '<a href="#t_firstclass">first |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 807 | class</a>' type. Notice that a function is not <a href="#wellformed">well |
| 808 | formed</a> if there exists a '<tt>ret</tt>' instruction inside of the function |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 809 | that returns a value that does not match the return type of the function.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 810 | |
| 811 | <h5>Semantics:</h5> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 812 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 813 | <p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 814 | the calling function's context. If the caller is a "<a |
| 815 | href="#i_call"><tt>call</tt></a> instruction, execution continues at the |
| 816 | instruction after the call. If the caller was an "<a |
| 817 | href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at the |
| 818 | beginning "normal" of the destination block. If the instruction returns a |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 819 | value, that value shall set the call or invoke instruction's return value.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 820 | |
| 821 | <h5>Example:</h5> |
| 822 | <pre> |
| 823 | ret int 5 <i>; Return an integer value of 5</i> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 824 | ret void <i>; Return from a void function</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 825 | </pre> |
| 826 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 827 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 828 | |
| 829 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 830 | <div class="doc_subsubsection"> |
| 831 | <a name="i_br">'<tt>br</tt>' Instruction</a> |
| 832 | </div> |
| 833 | |
| 834 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 835 | |
| 836 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 837 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 838 | <pre> |
| 839 | br bool <cond>, label <iftrue>, label <iffalse> |
| 840 | br label <dest> <i>; Unconditional branch</i> |
| 841 | </pre> |
| 842 | |
| 843 | <h5>Overview:</h5> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 844 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 845 | <p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 846 | different basic block in the current function. There are two forms of this |
| 847 | instruction, corresponding to a conditional branch and an unconditional |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 848 | branch.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 849 | |
| 850 | <h5>Arguments:</h5> |
| 851 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 852 | <p>The conditional branch form of the '<tt>br</tt>' instruction takes a single |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 853 | '<tt>bool</tt>' value and two '<tt>label</tt>' values. The unconditional form |
| 854 | of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 855 | target.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 856 | |
| 857 | <h5>Semantics:</h5> |
| 858 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 859 | <p>Upon execution of a conditional '<tt>br</tt>' instruction, the |
| 860 | '<tt>bool</tt>' argument is evaluated. If the value is <tt>true</tt>, control |
| 861 | flows to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is |
| 862 | <tt>false</tt>, control flows to the '<tt>iffalse</tt>' <tt>label</tt> |
| 863 | argument.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 864 | |
| 865 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 866 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 867 | <pre> |
| 868 | Test: |
| 869 | %cond = <a href="#i_setcc">seteq</a> int %a, %b |
| 870 | br bool %cond, label %IfEqual, label %IfUnequal |
| 871 | IfEqual: |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 872 | <a href="#i_ret">ret</a> int 1 |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 873 | IfUnequal: |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 874 | <a href="#i_ret">ret</a> int 0 |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 875 | </pre> |
| 876 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 877 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 878 | |
| 879 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 880 | <div class="doc_subsubsection"> |
| 881 | <a name="i_switch">'<tt>switch</tt>' Instruction</a> |
| 882 | </div> |
| 883 | |
| 884 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 885 | |
| 886 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 887 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 888 | <pre> |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 889 | switch uint <value>, label <defaultdest> [ int <val>, label &dest>, ... ] |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 890 | </pre> |
| 891 | |
| 892 | <h5>Overview:</h5> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 893 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 894 | <p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 895 | several different places. It is a generalization of the '<tt>br</tt>' |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 896 | instruction, allowing a branch to occur to one of many possible |
| 897 | destinations.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 898 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 899 | <h5>Arguments:</h5> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 900 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 901 | <p>The '<tt>switch</tt>' instruction uses three parameters: a '<tt>uint</tt>' |
Chris Lattner | c29b125 | 2003-05-08 05:08:48 +0000 | [diff] [blame] | 902 | comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 903 | an array of pairs of comparison value constants and '<tt>label</tt>'s.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 904 | |
| 905 | <h5>Semantics:</h5> |
| 906 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 907 | <p>The <tt>switch</tt> instruction specifies a table of values and destinations. |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 908 | When the '<tt>switch</tt>' instruction is executed, this table is searched for |
| 909 | the given value. If the value is found, the corresponding destination is |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 910 | branched to, otherwise the default value it transfered to.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 911 | |
Chris Lattner | c29b125 | 2003-05-08 05:08:48 +0000 | [diff] [blame] | 912 | <h5>Implementation:</h5> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 913 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 914 | <p>Depending on properties of the target machine and the particular |
| 915 | <tt>switch</tt> instruction, this instruction may be code generated as a series |
| 916 | of chained conditional branches, or with a lookup table.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 917 | |
| 918 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 919 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 920 | <pre> |
| 921 | <i>; Emulate a conditional br instruction</i> |
| 922 | %Val = <a href="#i_cast">cast</a> bool %value to uint |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 923 | switch uint %Val, label %truedest [int 0, label %falsedest ] |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 924 | |
| 925 | <i>; Emulate an unconditional br instruction</i> |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 926 | switch uint 0, label %dest [ ] |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 927 | |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 928 | <i>; Implement a jump table:</i> |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 929 | switch uint %val, label %otherwise [ int 0, label %onzero, |
| 930 | int 1, label %onone, |
| 931 | int 2, label %ontwo ] |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 932 | </pre> |
| 933 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 934 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 935 | |
| 936 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 937 | <div class="doc_subsubsection"> |
| 938 | <a name="i_invoke">'<tt>invoke</tt>' Instruction</a> |
| 939 | </div> |
| 940 | |
| 941 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 942 | |
| 943 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 944 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 945 | <pre> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 946 | <result> = invoke <ptr to function ty> %<function ptr val>(<function args>) |
| 947 | to label <normal label> except label <exception label> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 948 | </pre> |
| 949 | |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 950 | <h5>Overview:</h5> |
| 951 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 952 | <p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified |
Chris Lattner | b3ceec2 | 2003-08-28 22:12:25 +0000 | [diff] [blame] | 953 | function, with the possibility of control flow transfer to either the |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 954 | '<tt>normal</tt>' <tt>label</tt> label or the '<tt>exception</tt>' |
| 955 | <tt>label</tt>. If the callee function returns with the "<tt><a |
| 956 | href="#i_ret">ret</a></tt>" instruction, control flow will return to the |
| 957 | "normal" label. If the callee (or any indirect callees) returns with the "<a |
| 958 | href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted, and |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 959 | continued at the dynamically nearest "except" label.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 960 | |
| 961 | <h5>Arguments:</h5> |
| 962 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 963 | <p>This instruction requires several arguments:</p> |
| 964 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 965 | <ol> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 966 | |
| 967 | <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 968 | function value being invoked. In most cases, this is a direct function |
Misha Brukman | e6fe671 | 2002-09-18 02:35:14 +0000 | [diff] [blame] | 969 | invocation, but indirect <tt>invoke</tt>s are just as possible, branching off |
Chris Lattner | b3ceec2 | 2003-08-28 22:12:25 +0000 | [diff] [blame] | 970 | an arbitrary pointer to function value. |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 971 | |
| 972 | <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a |
| 973 | function to be invoked. |
| 974 | |
| 975 | <li>'<tt>function args</tt>': argument list whose types match the function |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 976 | signature argument types. If the function signature indicates the function |
| 977 | accepts a variable number of arguments, the extra arguments can be specified. |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 978 | |
| 979 | <li>'<tt>normal label</tt>': the label reached when the called function executes |
| 980 | a '<tt><a href="#i_ret">ret</a></tt>' instruction. |
| 981 | |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 982 | <li>'<tt>exception label</tt>': the label reached when a callee returns with the |
| 983 | <a href="#i_unwind"><tt>unwind</tt></a> instruction. |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 984 | </ol> |
| 985 | |
| 986 | <h5>Semantics:</h5> |
| 987 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 988 | <p>This instruction is designed to operate as a standard '<tt><a |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 989 | href="#i_call">call</a></tt>' instruction in most regards. The primary |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 990 | difference is that it establishes an association with a label, which is used by the runtime library to unwind the stack.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 991 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 992 | <p>This instruction is used in languages with destructors to ensure that proper |
Chris Lattner | b3ceec2 | 2003-08-28 22:12:25 +0000 | [diff] [blame] | 993 | cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown |
| 994 | exception. Additionally, this is important for implementation of |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 995 | '<tt>catch</tt>' clauses in high-level languages that support them.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 996 | |
| 997 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 998 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 999 | <pre> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1000 | %retval = invoke int %Test(int 15) |
Chris Lattner | b3ceec2 | 2003-08-28 22:12:25 +0000 | [diff] [blame] | 1001 | to label %Continue |
| 1002 | except label %TestCleanup <i>; {int}:retval set</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1003 | </pre> |
| 1004 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1005 | </div> |
| 1006 | |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1007 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1008 | <div class="doc_subsubsection"> |
| 1009 | <a name="i_unwind">'<tt>unwind</tt>' Instruction</a> |
| 1010 | </div> |
| 1011 | |
| 1012 | <div class="doc_text"> |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1013 | |
| 1014 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1015 | |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1016 | <pre> |
| 1017 | unwind |
| 1018 | </pre> |
| 1019 | |
| 1020 | <h5>Overview:</h5> |
| 1021 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1022 | <p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow |
| 1023 | at the first callee in the dynamic call stack which used an <a |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1024 | href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1025 | primarily used to implement exception handling.</p> |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1026 | |
| 1027 | <h5>Semantics:</h5> |
| 1028 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1029 | <p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1030 | immediately halt. The dynamic call stack is then searched for the first <a |
| 1031 | href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found, |
| 1032 | execution continues at the "exceptional" destination block specified by the |
| 1033 | <tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1034 | dynamic call chain, undefined behavior results.</p> |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1035 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1036 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1037 | |
| 1038 | <!-- ======================================================================= --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1039 | <div class="doc_subsection"> |
| 1040 | <a name="binaryops">Binary Operations</a> |
| 1041 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1042 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1043 | <div class="doc_text"> |
| 1044 | |
| 1045 | <p>Binary operators are used to do most of the computation in a program. They |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1046 | require two operands, execute an operation on them, and produce a single value. |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1047 | The result value of a binary operator is not necessarily the same type as its |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1048 | operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1049 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1050 | <p>There are several different binary operators:</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1051 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1052 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1053 | |
| 1054 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1055 | <div class="doc_subsubsection"> |
| 1056 | <a name="i_add">'<tt>add</tt>' Instruction</a> |
| 1057 | </div> |
| 1058 | |
| 1059 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1060 | |
| 1061 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1062 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1063 | <pre> |
| 1064 | <result> = add <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 1065 | </pre> |
| 1066 | |
| 1067 | <h5>Overview:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1068 | |
| 1069 | <p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1070 | |
| 1071 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1072 | |
| 1073 | <p>The two arguments to the '<tt>add</tt>' instruction must be either <a |
| 1074 | href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> |
| 1075 | values. Both arguments must have identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1076 | |
| 1077 | <h5>Semantics:</h5> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1078 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1079 | <p>The value produced is the integer or floating point sum of the two |
| 1080 | operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1081 | |
| 1082 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1083 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1084 | <pre> |
| 1085 | <result> = add int 4, %var <i>; yields {int}:result = 4 + %var</i> |
| 1086 | </pre> |
| 1087 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1088 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1089 | |
| 1090 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1091 | <div class="doc_subsubsection"> |
| 1092 | <a name="i_sub">'<tt>sub</tt>' Instruction</a> |
| 1093 | </div> |
| 1094 | |
| 1095 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1096 | |
| 1097 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1098 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1099 | <pre> |
| 1100 | <result> = sub <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 1101 | </pre> |
| 1102 | |
| 1103 | <h5>Overview:</h5> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1104 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1105 | <p>The '<tt>sub</tt>' instruction returns the difference of its two |
| 1106 | operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1107 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1108 | <p>Note that the '<tt>sub</tt>' instruction is used to represent the |
| 1109 | '<tt>neg</tt>' instruction present in most other intermediate |
| 1110 | representations.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1111 | |
| 1112 | <h5>Arguments:</h5> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1113 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1114 | <p>The two arguments to the '<tt>sub</tt>' instruction must be either <a |
Chris Lattner | eaee9e1 | 2002-09-03 00:52:52 +0000 | [diff] [blame] | 1115 | href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1116 | values. Both arguments must have identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1117 | |
| 1118 | <h5>Semantics:</h5> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1119 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1120 | <p>The value produced is the integer or floating point difference of the two |
| 1121 | operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1122 | |
| 1123 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1124 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1125 | <pre> |
| 1126 | <result> = sub int 4, %var <i>; yields {int}:result = 4 - %var</i> |
| 1127 | <result> = sub int 0, %val <i>; yields {int}:result = -%var</i> |
| 1128 | </pre> |
| 1129 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1130 | </div> |
| 1131 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1132 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1133 | <div class="doc_subsubsection"> |
| 1134 | <a name="i_mul">'<tt>mul</tt>' Instruction</a> |
| 1135 | </div> |
| 1136 | |
| 1137 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1138 | |
| 1139 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1140 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1141 | <pre> |
| 1142 | <result> = mul <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 1143 | </pre> |
| 1144 | |
| 1145 | <h5>Overview:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1146 | |
| 1147 | <p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1148 | |
| 1149 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1150 | |
| 1151 | <p>The two arguments to the '<tt>mul</tt>' instruction must be either <a |
| 1152 | href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> |
| 1153 | values. Both arguments must have identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1154 | |
| 1155 | <h5>Semantics:</h5> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1156 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1157 | <p>The value produced is the integer or floating point product of the two |
| 1158 | operands.</p> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1159 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1160 | <p>There is no signed vs unsigned multiplication. The appropriate action is |
| 1161 | taken based on the type of the operand.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1162 | |
| 1163 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1164 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1165 | <pre> |
| 1166 | <result> = mul int 4, %var <i>; yields {int}:result = 4 * %var</i> |
| 1167 | </pre> |
| 1168 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1169 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1170 | |
| 1171 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1172 | <div class="doc_subsubsection"> |
| 1173 | <a name="i_div">'<tt>div</tt>' Instruction</a> |
| 1174 | </div> |
| 1175 | |
| 1176 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1177 | |
| 1178 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1179 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1180 | <pre> |
| 1181 | <result> = div <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 1182 | </pre> |
| 1183 | |
| 1184 | <h5>Overview:</h5> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1185 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1186 | <p>The '<tt>div</tt>' instruction returns the quotient of its two operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1187 | |
| 1188 | <h5>Arguments:</h5> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1189 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1190 | <p>The two arguments to the '<tt>div</tt>' instruction must be either <a |
Chris Lattner | eaee9e1 | 2002-09-03 00:52:52 +0000 | [diff] [blame] | 1191 | href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1192 | values. Both arguments must have identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1193 | |
| 1194 | <h5>Semantics:</h5> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1195 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1196 | <p>The value produced is the integer or floating point quotient of the two |
| 1197 | operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1198 | |
| 1199 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1200 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1201 | <pre> |
| 1202 | <result> = div int 4, %var <i>; yields {int}:result = 4 / %var</i> |
| 1203 | </pre> |
| 1204 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1205 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1206 | |
| 1207 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1208 | <div class="doc_subsubsection"> |
| 1209 | <a name="i_rem">'<tt>rem</tt>' Instruction</a> |
| 1210 | </div> |
| 1211 | |
| 1212 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1213 | |
| 1214 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1215 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1216 | <pre> |
| 1217 | <result> = rem <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 1218 | </pre> |
| 1219 | |
| 1220 | <h5>Overview:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1221 | |
| 1222 | <p>The '<tt>rem</tt>' instruction returns the remainder from the division of its |
| 1223 | two operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1224 | |
| 1225 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1226 | |
| 1227 | <p>The two arguments to the '<tt>rem</tt>' instruction must be either <a |
| 1228 | href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> |
| 1229 | values. Both arguments must have identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1230 | |
| 1231 | <h5>Semantics:</h5> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1232 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1233 | <p>This returns the <i>remainder</i> of a division (where the result has the |
| 1234 | same sign as the divisor), not the <i>modulus</i> (where the result has the same |
| 1235 | sign as the dividend) of a value. For more information about the difference, |
| 1236 | see: <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The Math |
| 1237 | Forum</a>.</p> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1238 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1239 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1240 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1241 | <pre> |
| 1242 | <result> = rem int 4, %var <i>; yields {int}:result = 4 % %var</i> |
| 1243 | </pre> |
| 1244 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1245 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1246 | |
| 1247 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1248 | <div class="doc_subsubsection"> |
| 1249 | <a name="i_setcc">'<tt>set<i>cc</i></tt>' Instructions</a> |
| 1250 | </div> |
| 1251 | |
| 1252 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1253 | |
| 1254 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1255 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1256 | <pre> |
| 1257 | <result> = seteq <ty> <var1>, <var2> <i>; yields {bool}:result</i> |
| 1258 | <result> = setne <ty> <var1>, <var2> <i>; yields {bool}:result</i> |
| 1259 | <result> = setlt <ty> <var1>, <var2> <i>; yields {bool}:result</i> |
| 1260 | <result> = setgt <ty> <var1>, <var2> <i>; yields {bool}:result</i> |
| 1261 | <result> = setle <ty> <var1>, <var2> <i>; yields {bool}:result</i> |
| 1262 | <result> = setge <ty> <var1>, <var2> <i>; yields {bool}:result</i> |
| 1263 | </pre> |
| 1264 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1265 | <h5>Overview:</h5> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1266 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1267 | <p>The '<tt>set<i>cc</i></tt>' family of instructions returns a boolean value |
| 1268 | based on a comparison of their two operands.</p> |
| 1269 | |
| 1270 | <h5>Arguments:</h5> |
| 1271 | |
| 1272 | <p>The two arguments to the '<tt>set<i>cc</i></tt>' instructions must be of <a |
| 1273 | href="#t_firstclass">first class</a> type (it is not possible to compare |
| 1274 | '<tt>label</tt>'s, '<tt>array</tt>'s, '<tt>structure</tt>' or '<tt>void</tt>' |
| 1275 | values, etc...). Both arguments must have identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1276 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1277 | <h5>Semantics:</h5> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1278 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1279 | <p>The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value |
| 1280 | if both operands are equal.<br> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1281 | |
| 1282 | The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if |
| 1283 | both operands are unequal.<br> |
| 1284 | |
| 1285 | The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if |
| 1286 | the first operand is less than the second operand.<br> |
| 1287 | |
| 1288 | The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if |
| 1289 | the first operand is greater than the second operand.<br> |
| 1290 | |
| 1291 | The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if |
| 1292 | the first operand is less than or equal to the second operand.<br> |
| 1293 | |
| 1294 | The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1295 | the first operand is greater than or equal to the second operand.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1296 | |
| 1297 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1298 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1299 | <pre> |
| 1300 | <result> = seteq int 4, 5 <i>; yields {bool}:result = false</i> |
| 1301 | <result> = setne float 4, 5 <i>; yields {bool}:result = true</i> |
| 1302 | <result> = setlt uint 4, 5 <i>; yields {bool}:result = true</i> |
| 1303 | <result> = setgt sbyte 4, 5 <i>; yields {bool}:result = false</i> |
| 1304 | <result> = setle sbyte 4, 5 <i>; yields {bool}:result = true</i> |
| 1305 | <result> = setge sbyte 4, 5 <i>; yields {bool}:result = false</i> |
| 1306 | </pre> |
| 1307 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1308 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1309 | |
| 1310 | <!-- ======================================================================= --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1311 | <div class="doc_subsection"> |
| 1312 | <a name="bitwiseops">Bitwise Binary Operations</a> |
| 1313 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1314 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1315 | <div class="doc_text"> |
| 1316 | |
| 1317 | <p>Bitwise binary operators are used to do various forms of bit-twiddling in a |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1318 | program. They are generally very efficient instructions, and can commonly be |
| 1319 | strength reduced from other instructions. They require two operands, execute an |
| 1320 | operation on them, and produce a single value. The resulting value of the |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1321 | bitwise binary operators is always the same type as its first operand.</p> |
| 1322 | |
| 1323 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1324 | |
| 1325 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1326 | <div class="doc_subsubsection"> |
| 1327 | <a name="i_and">'<tt>and</tt>' Instruction</a> |
| 1328 | </div> |
| 1329 | |
| 1330 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1331 | |
| 1332 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1333 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1334 | <pre> |
| 1335 | <result> = and <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 1336 | </pre> |
| 1337 | |
| 1338 | <h5>Overview:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1339 | |
| 1340 | <p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two |
| 1341 | operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1342 | |
| 1343 | <h5>Arguments:</h5> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1344 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1345 | <p>The two arguments to the '<tt>and</tt>' instruction must be <a |
Chris Lattner | eaee9e1 | 2002-09-03 00:52:52 +0000 | [diff] [blame] | 1346 | href="#t_integral">integral</a> values. Both arguments must have identical |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1347 | types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1348 | |
| 1349 | <h5>Semantics:</h5> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1350 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1351 | <p>The truth table used for the '<tt>and</tt>' instruction is:</p> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1352 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1353 | <p> |
| 1354 | <center> |
| 1355 | <table border="1" cellspacing="0" cellpadding="4"> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1356 | <tr><td>In0</td> <td>In1</td> <td>Out</td></tr> |
| 1357 | <tr><td>0</td> <td>0</td> <td>0</td></tr> |
| 1358 | <tr><td>0</td> <td>1</td> <td>0</td></tr> |
| 1359 | <tr><td>1</td> <td>0</td> <td>0</td></tr> |
| 1360 | <tr><td>1</td> <td>1</td> <td>1</td></tr> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1361 | </table></center> |
| 1362 | </p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1363 | |
| 1364 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1365 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1366 | <pre> |
| 1367 | <result> = and int 4, %var <i>; yields {int}:result = 4 & %var</i> |
| 1368 | <result> = and int 15, 40 <i>; yields {int}:result = 8</i> |
| 1369 | <result> = and int 4, 8 <i>; yields {int}:result = 0</i> |
| 1370 | </pre> |
| 1371 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1372 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1373 | |
| 1374 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1375 | <div class="doc_subsubsection"> |
| 1376 | <a name="i_or">'<tt>or</tt>' Instruction</a> |
| 1377 | </div> |
| 1378 | |
| 1379 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1380 | |
| 1381 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1382 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1383 | <pre> |
| 1384 | <result> = or <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 1385 | </pre> |
| 1386 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1387 | <h5>Overview:</h5> |
| 1388 | |
| 1389 | <p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its |
| 1390 | two operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1391 | |
| 1392 | <h5>Arguments:</h5> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1393 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1394 | <p>The two arguments to the '<tt>or</tt>' instruction must be <a |
Chris Lattner | eaee9e1 | 2002-09-03 00:52:52 +0000 | [diff] [blame] | 1395 | href="#t_integral">integral</a> values. Both arguments must have identical |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1396 | types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1397 | |
| 1398 | <h5>Semantics:</h5> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1399 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1400 | <p>The truth table used for the '<tt>or</tt>' instruction is:</p> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1401 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1402 | <p> |
| 1403 | <center><table border="1" cellspacing="0" cellpadding="4"> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1404 | <tr><td>In0</td> <td>In1</td> <td>Out</td></tr> |
| 1405 | <tr><td>0</td> <td>0</td> <td>0</td></tr> |
| 1406 | <tr><td>0</td> <td>1</td> <td>1</td></tr> |
| 1407 | <tr><td>1</td> <td>0</td> <td>1</td></tr> |
| 1408 | <tr><td>1</td> <td>1</td> <td>1</td></tr> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1409 | </table></center> |
| 1410 | </p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1411 | |
| 1412 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1413 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1414 | <pre> |
| 1415 | <result> = or int 4, %var <i>; yields {int}:result = 4 | %var</i> |
| 1416 | <result> = or int 15, 40 <i>; yields {int}:result = 47</i> |
| 1417 | <result> = or int 4, 8 <i>; yields {int}:result = 12</i> |
| 1418 | </pre> |
| 1419 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1420 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1421 | |
| 1422 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1423 | <div class="doc_subsubsection"> |
| 1424 | <a name="i_xor">'<tt>xor</tt>' Instruction</a> |
| 1425 | </div> |
| 1426 | |
| 1427 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1428 | |
| 1429 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1430 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1431 | <pre> |
| 1432 | <result> = xor <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 1433 | </pre> |
| 1434 | |
| 1435 | <h5>Overview:</h5> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1436 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1437 | <p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of |
| 1438 | its two operands. The <tt>xor</tt> is used to implement the "one's complement" |
| 1439 | operation, which is the "~" operator in C.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1440 | |
| 1441 | <h5>Arguments:</h5> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1442 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1443 | <p>The two arguments to the '<tt>xor</tt>' instruction must be <a |
Chris Lattner | eaee9e1 | 2002-09-03 00:52:52 +0000 | [diff] [blame] | 1444 | href="#t_integral">integral</a> values. Both arguments must have identical |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1445 | types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1446 | |
| 1447 | <h5>Semantics:</h5> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1448 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1449 | <p>The truth table used for the '<tt>xor</tt>' instruction is:</p> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1450 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1451 | <p> |
| 1452 | <center><table border="1" cellspacing="0" cellpadding="4"> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1453 | <tr><td>In0</td> <td>In1</td> <td>Out</td></tr> |
| 1454 | <tr><td>0</td> <td>0</td> <td>0</td></tr> |
| 1455 | <tr><td>0</td> <td>1</td> <td>1</td></tr> |
| 1456 | <tr><td>1</td> <td>0</td> <td>1</td></tr> |
| 1457 | <tr><td>1</td> <td>1</td> <td>0</td></tr> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1458 | </table></center> |
| 1459 | <p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1460 | |
| 1461 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1462 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1463 | <pre> |
| 1464 | <result> = xor int 4, %var <i>; yields {int}:result = 4 ^ %var</i> |
| 1465 | <result> = xor int 15, 40 <i>; yields {int}:result = 39</i> |
| 1466 | <result> = xor int 4, 8 <i>; yields {int}:result = 12</i> |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1467 | <result> = xor int %V, -1 <i>; yields {int}:result = ~%V</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1468 | </pre> |
| 1469 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1470 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1471 | |
| 1472 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1473 | <div class="doc_subsubsection"> |
| 1474 | <a name="i_shl">'<tt>shl</tt>' Instruction</a> |
| 1475 | </div> |
| 1476 | |
| 1477 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1478 | |
| 1479 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1480 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1481 | <pre> |
| 1482 | <result> = shl <ty> <var1>, ubyte <var2> <i>; yields {ty}:result</i> |
| 1483 | </pre> |
| 1484 | |
| 1485 | <h5>Overview:</h5> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1486 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1487 | <p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left |
| 1488 | a specified number of bits.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1489 | |
| 1490 | <h5>Arguments:</h5> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1491 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1492 | <p>The first argument to the '<tt>shl</tt>' instruction must be an <a |
Chris Lattner | eaee9e1 | 2002-09-03 00:52:52 +0000 | [diff] [blame] | 1493 | href="#t_integer">integer</a> type. The second argument must be an |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1494 | '<tt>ubyte</tt>' type.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1495 | |
| 1496 | <h5>Semantics:</h5> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1497 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1498 | <p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1499 | |
| 1500 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1501 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1502 | <pre> |
| 1503 | <result> = shl int 4, ubyte %var <i>; yields {int}:result = 4 << %var</i> |
| 1504 | <result> = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i> |
| 1505 | <result> = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i> |
| 1506 | </pre> |
| 1507 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1508 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1509 | |
| 1510 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1511 | <div class="doc_subsubsection"> |
| 1512 | <a name="i_shr">'<tt>shr</tt>' Instruction</a> |
| 1513 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1514 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1515 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1516 | |
| 1517 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1518 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1519 | <pre> |
| 1520 | <result> = shr <ty> <var1>, ubyte <var2> <i>; yields {ty}:result</i> |
| 1521 | </pre> |
| 1522 | |
| 1523 | <h5>Overview:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1524 | |
| 1525 | <p>The '<tt>shr</tt>' instruction returns the first operand shifted to the right |
| 1526 | a specified number of bits.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1527 | |
| 1528 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1529 | |
| 1530 | <p>The first argument to the '<tt>shr</tt>' instruction must be an <a |
| 1531 | href="#t_integer">integer</a> type. The second argument must be an |
| 1532 | '<tt>ubyte</tt>' type.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1533 | |
| 1534 | <h5>Semantics:</h5> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1535 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1536 | <p>If the first argument is a <a href="#t_signed">signed</a> type, the most |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1537 | significant bit is duplicated in the newly free'd bit positions. If the first |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1538 | argument is unsigned, zero bits shall fill the empty positions.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1539 | |
| 1540 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1541 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1542 | <pre> |
| 1543 | <result> = shr int 4, ubyte %var <i>; yields {int}:result = 4 >> %var</i> |
Chris Lattner | 8c6bb90 | 2003-06-18 21:30:51 +0000 | [diff] [blame] | 1544 | <result> = shr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1545 | <result> = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i> |
Chris Lattner | 8c6bb90 | 2003-06-18 21:30:51 +0000 | [diff] [blame] | 1546 | <result> = shr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i> |
| 1547 | <result> = shr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1548 | </pre> |
| 1549 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1550 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1551 | |
| 1552 | <!-- ======================================================================= --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1553 | <div class="doc_subsection"> |
| 1554 | <a name="memoryops">Memory Access Operations</div> |
| 1555 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1556 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1557 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1558 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1559 | <p>A key design point of an SSA-based representation is how it represents |
| 1560 | memory. In LLVM, no memory locations are in SSA form, which makes things very |
| 1561 | simple. This section describes how to read, write, allocate and free memory in |
| 1562 | LLVM.</p> |
| 1563 | |
| 1564 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1565 | |
| 1566 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1567 | <div class="doc_subsubsection"> |
| 1568 | <a name="i_malloc">'<tt>malloc</tt>' Instruction</a> |
| 1569 | </div> |
| 1570 | |
| 1571 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1572 | |
| 1573 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1574 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1575 | <pre> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1576 | <result> = malloc <type>, uint <NumElements> <i>; yields {type*}:result</i> |
| 1577 | <result> = malloc <type> <i>; yields {type*}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1578 | </pre> |
| 1579 | |
| 1580 | <h5>Overview:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1581 | |
| 1582 | <p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and |
| 1583 | returns a pointer to it.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1584 | |
| 1585 | <h5>Arguments:</h5> |
| 1586 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1587 | <p>The the '<tt>malloc</tt>' instruction allocates |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1588 | <tt>sizeof(<type>)*NumElements</tt> bytes of memory from the operating |
| 1589 | system, and returns a pointer of the appropriate type to the program. The |
| 1590 | second form of the instruction is a shorter version of the first instruction |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1591 | that defaults to allocating one element.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1592 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1593 | <p>'<tt>type</tt>' must be a sized type.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1594 | |
| 1595 | <h5>Semantics:</h5> |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1596 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1597 | <p>Memory is allocated using the system "<tt>malloc</tt>" function, and a |
| 1598 | pointer is returned.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1599 | |
| 1600 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1601 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1602 | <pre> |
| 1603 | %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i> |
| 1604 | |
| 1605 | %size = <a href="#i_add">add</a> uint 2, 2 <i>; yields {uint}:size = uint 4</i> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1606 | %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i> |
| 1607 | %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1608 | </pre> |
| 1609 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1610 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1611 | |
| 1612 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1613 | <div class="doc_subsubsection"> |
| 1614 | <a name="i_free">'<tt>free</tt>' Instruction</a> |
| 1615 | </div> |
| 1616 | |
| 1617 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1618 | |
| 1619 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1620 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1621 | <pre> |
| 1622 | free <type> <value> <i>; yields {void}</i> |
| 1623 | </pre> |
| 1624 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1625 | <h5>Overview:</h5> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1626 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1627 | <p>The '<tt>free</tt>' instruction returns memory back to the unused memory |
| 1628 | heap, to be reallocated in the future.<p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1629 | |
| 1630 | <h5>Arguments:</h5> |
| 1631 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1632 | <p>'<tt>value</tt>' shall be a pointer value that points to a value that was |
| 1633 | allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1634 | |
| 1635 | <h5>Semantics:</h5> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1636 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1637 | <p>Access to the memory pointed to by the pointer is not longer defined after |
| 1638 | this instruction executes.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1639 | |
| 1640 | <h5>Example:</h5> |
| 1641 | <pre> |
| 1642 | %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i> |
| 1643 | free [4 x ubyte]* %array |
| 1644 | </pre> |
| 1645 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1646 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1647 | |
| 1648 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1649 | <div class="doc_subsubsection"> |
| 1650 | <a name="i_alloca">'<tt>alloca</tt>' Instruction</a> |
| 1651 | </div> |
| 1652 | |
| 1653 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1654 | |
| 1655 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1656 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1657 | <pre> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1658 | <result> = alloca <type>, uint <NumElements> <i>; yields {type*}:result</i> |
| 1659 | <result> = alloca <type> <i>; yields {type*}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1660 | </pre> |
| 1661 | |
| 1662 | <h5>Overview:</h5> |
| 1663 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1664 | <p>The '<tt>alloca</tt>' instruction allocates memory on the current stack frame |
| 1665 | of the procedure that is live until the current function returns to its |
| 1666 | caller.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1667 | |
| 1668 | <h5>Arguments:</h5> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1669 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1670 | <p>The the '<tt>alloca</tt>' instruction allocates |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1671 | <tt>sizeof(<type>)*NumElements</tt> bytes of memory on the runtime stack, |
| 1672 | returning a pointer of the appropriate type to the program. The second form of |
| 1673 | the instruction is a shorter version of the first that defaults to allocating |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1674 | one element.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1675 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1676 | <p>'<tt>type</tt>' may be any sized type.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1677 | |
| 1678 | <h5>Semantics:</h5> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1679 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1680 | <p>Memory is allocated, a pointer is returned. '<tt>alloca</tt>'d memory is |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1681 | automatically released when the function returns. The '<tt>alloca</tt>' |
| 1682 | instruction is commonly used to represent automatic variables that must have an |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1683 | address available. When the function returns (either with the <tt><a |
| 1684 | href="#i_ret">ret</a></tt> or <tt><a href="#i_invoke">invoke</a></tt> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1685 | instructions), the memory is reclaimed.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1686 | |
| 1687 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1688 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1689 | <pre> |
| 1690 | %ptr = alloca int <i>; yields {int*}:ptr</i> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1691 | %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1692 | </pre> |
| 1693 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1694 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1695 | |
| 1696 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1697 | <div class="doc_subsubsection"> |
| 1698 | <a name="i_load">'<tt>load</tt>' Instruction</a> |
| 1699 | </div> |
| 1700 | |
| 1701 | <div class="doc_text"> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1702 | |
| 1703 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1704 | |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1705 | <pre> |
| 1706 | <result> = load <ty>* <pointer> |
Chris Lattner | f065107 | 2003-09-08 18:27:49 +0000 | [diff] [blame] | 1707 | <result> = volatile load <ty>* <pointer> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1708 | </pre> |
| 1709 | |
| 1710 | <h5>Overview:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1711 | |
| 1712 | <p>The '<tt>load</tt>' instruction is used to read from memory.</p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1713 | |
| 1714 | <h5>Arguments:</h5> |
| 1715 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1716 | <p>The argument to the '<tt>load</tt>' instruction specifies the memory address |
| 1717 | to load from. The pointer must point to a <a href="t_firstclass">first |
| 1718 | class</a> type. If the <tt>load</tt> is marked as <tt>volatile</tt> then the |
| 1719 | optimizer is not allowed to modify the number or order of execution of this |
| 1720 | <tt>load</tt> with other volatile <tt>load</tt> and <tt><a |
| 1721 | href="#i_store">store</a></tt> instructions. </p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1722 | |
| 1723 | <h5>Semantics:</h5> |
| 1724 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1725 | <p>The location of memory pointed to is loaded.</p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1726 | |
| 1727 | <h5>Examples:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1728 | |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1729 | <pre> |
| 1730 | %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i> |
| 1731 | <a href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i> |
| 1732 | %val = load int* %ptr <i>; yields {int}:val = int 3</i> |
| 1733 | </pre> |
| 1734 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1735 | </div> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1736 | |
| 1737 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1738 | <div class="doc_subsubsection"> |
| 1739 | <a name="i_store">'<tt>store</tt>' Instruction</a> |
| 1740 | </div> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1741 | |
| 1742 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1743 | |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1744 | <pre> |
| 1745 | store <ty> <value>, <ty>* <pointer> <i>; yields {void}</i> |
Chris Lattner | f065107 | 2003-09-08 18:27:49 +0000 | [diff] [blame] | 1746 | volatile store <ty> <value>, <ty>* <pointer> <i>; yields {void}</i> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1747 | </pre> |
| 1748 | |
| 1749 | <h5>Overview:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1750 | |
| 1751 | <p>The '<tt>store</tt>' instruction is used to write to memory.</p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1752 | |
| 1753 | <h5>Arguments:</h5> |
| 1754 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1755 | <p>There are two arguments to the '<tt>store</tt>' instruction: a value to store |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1756 | and an address to store it into. The type of the '<tt><pointer></tt>' |
Chris Lattner | f065107 | 2003-09-08 18:27:49 +0000 | [diff] [blame] | 1757 | operand must be a pointer to the type of the '<tt><value></tt>' operand. |
| 1758 | If the <tt>store</tt> is marked as <tt>volatile</tt> then the optimizer is not |
| 1759 | allowed to modify the number or order of execution of this <tt>store</tt> with |
| 1760 | other volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1761 | instructions.</p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1762 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1763 | <h5>Semantics:</h5> |
| 1764 | |
| 1765 | <p>The contents of memory are updated to contain '<tt><value></tt>' at the |
| 1766 | location specified by the '<tt><pointer></tt>' operand.</p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1767 | |
| 1768 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1769 | |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1770 | <pre> |
| 1771 | %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i> |
| 1772 | <a href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i> |
| 1773 | %val = load int* %ptr <i>; yields {int}:val = int 3</i> |
| 1774 | </pre> |
| 1775 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1776 | </div> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 1777 | |
| 1778 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1779 | <div class="doc_subsubsection"> |
| 1780 | <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a> |
| 1781 | </div> |
| 1782 | |
| 1783 | <div class="doc_text"> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1784 | |
| 1785 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1786 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1787 | <pre> |
Chris Lattner | 3dfa10b | 2002-12-13 06:01:21 +0000 | [diff] [blame] | 1788 | <result> = getelementptr <ty>* <ptrval>{, long <aidx>|, ubyte <sidx>}* |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1789 | </pre> |
| 1790 | |
| 1791 | <h5>Overview:</h5> |
| 1792 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1793 | <p>The '<tt>getelementptr</tt>' instruction is used to get the address of a |
| 1794 | subelement of an aggregate data structure.</p> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1795 | |
| 1796 | <h5>Arguments:</h5> |
| 1797 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1798 | <p>This instruction takes a list of <tt>long</tt> values and <tt>ubyte</tt> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1799 | constants that indicate what form of addressing to perform. The actual types of |
| 1800 | the arguments provided depend on the type of the first pointer argument. The |
| 1801 | '<tt>getelementptr</tt>' instruction is used to index down through the type |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1802 | levels of a structure.</p> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1803 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1804 | <p>For example, let's consider a C code fragment and how it gets compiled to |
| 1805 | LLVM:</p> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1806 | |
| 1807 | <pre> |
| 1808 | struct RT { |
| 1809 | char A; |
| 1810 | int B[10][20]; |
| 1811 | char C; |
| 1812 | }; |
| 1813 | struct ST { |
| 1814 | int X; |
| 1815 | double Y; |
| 1816 | struct RT Z; |
| 1817 | }; |
| 1818 | |
| 1819 | int *foo(struct ST *s) { |
| 1820 | return &s[1].Z.B[5][13]; |
| 1821 | } |
| 1822 | </pre> |
| 1823 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1824 | <p>The LLVM code generated by the GCC frontend is:</p> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1825 | |
| 1826 | <pre> |
| 1827 | %RT = type { sbyte, [10 x [20 x int]], sbyte } |
| 1828 | %ST = type { int, double, %RT } |
| 1829 | |
| 1830 | int* "foo"(%ST* %s) { |
Chris Lattner | 3dfa10b | 2002-12-13 06:01:21 +0000 | [diff] [blame] | 1831 | %reg = getelementptr %ST* %s, long 1, ubyte 2, ubyte 1, long 5, long 13 |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1832 | ret int* %reg |
| 1833 | } |
| 1834 | </pre> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1835 | |
| 1836 | <h5>Semantics:</h5> |
| 1837 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1838 | <p>The index types specified for the '<tt>getelementptr</tt>' instruction depend |
| 1839 | on the pointer type that is being index into. <a href="t_pointer">Pointer</a> |
| 1840 | and <a href="t_array">array</a> types require '<tt>long</tt>' values, and <a |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1841 | href="t_struct">structure</a> types require '<tt>ubyte</tt>' |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1842 | <b>constants</b>.</p> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1843 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1844 | <p>In the example above, the first index is indexing into the '<tt>%ST*</tt>' |
| 1845 | type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT |
| 1846 | }</tt>' type, a structure. The second index indexes into the third element of |
| 1847 | the structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]], |
| 1848 | sbyte }</tt>' type, another structure. The third index indexes into the second |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1849 | element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an |
| 1850 | array. The two dimensions of the array are subscripted into, yielding an |
| 1851 | '<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction return a pointer |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1852 | to this element, thus yielding a '<tt>int*</tt>' type.</p> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1853 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1854 | <p>Note that it is perfectly legal to index partially through a structure, |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1855 | returning a pointer to an inner element. Because of this, the LLVM code for the |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1856 | given testcase is equivalent to:</p> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1857 | |
| 1858 | <pre> |
| 1859 | int* "foo"(%ST* %s) { |
Chris Lattner | 3dfa10b | 2002-12-13 06:01:21 +0000 | [diff] [blame] | 1860 | %t1 = getelementptr %ST* %s , long 1 <i>; yields %ST*:%t1</i> |
| 1861 | %t2 = getelementptr %ST* %t1, long 0, ubyte 2 <i>; yields %RT*:%t2</i> |
| 1862 | %t3 = getelementptr %RT* %t2, long 0, ubyte 1 <i>; yields [10 x [20 x int]]*:%t3</i> |
| 1863 | %t4 = getelementptr [10 x [20 x int]]* %t3, long 0, long 5 <i>; yields [20 x int]*:%t4</i> |
| 1864 | %t5 = getelementptr [20 x int]* %t4, long 0, long 13 <i>; yields int*:%t5</i> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1865 | ret int* %t5 |
| 1866 | } |
| 1867 | </pre> |
| 1868 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1869 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1870 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1871 | <pre> |
Chris Lattner | f31860b | 2002-08-19 21:14:38 +0000 | [diff] [blame] | 1872 | <i>; yields [12 x ubyte]*:aptr</i> |
Chris Lattner | 3dfa10b | 2002-12-13 06:01:21 +0000 | [diff] [blame] | 1873 | %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, ubyte 1 |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1874 | </pre> |
| 1875 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1876 | </div> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1877 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1878 | <!-- ======================================================================= --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1879 | <div class="doc_subsection"> |
| 1880 | <a name="otherops">Other Operations</a> |
| 1881 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1882 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1883 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1884 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1885 | <p>The instructions in this catagory are the "miscellaneous" instructions, which |
| 1886 | defy better classification.</p> |
| 1887 | |
| 1888 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1889 | |
| 1890 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1891 | <div class="doc_subsubsection"> |
| 1892 | <a name="i_phi">'<tt>phi</tt>' Instruction</a> |
| 1893 | </div> |
| 1894 | |
| 1895 | <div class="doc_text"> |
Chris Lattner | 33ba0d9 | 2001-07-09 00:26:23 +0000 | [diff] [blame] | 1896 | |
| 1897 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1898 | |
Chris Lattner | 33ba0d9 | 2001-07-09 00:26:23 +0000 | [diff] [blame] | 1899 | <pre> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1900 | <result> = phi <ty> [ <val0>, <label0>], ... |
Chris Lattner | 33ba0d9 | 2001-07-09 00:26:23 +0000 | [diff] [blame] | 1901 | </pre> |
| 1902 | |
| 1903 | <h5>Overview:</h5> |
| 1904 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1905 | <p>The '<tt>phi</tt>' instruction is used to implement the φ node in the SSA |
| 1906 | graph representing the function.</p> |
Chris Lattner | 33ba0d9 | 2001-07-09 00:26:23 +0000 | [diff] [blame] | 1907 | |
| 1908 | <h5>Arguments:</h5> |
| 1909 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1910 | <p>The type of the incoming values are specified with the first type field. |
| 1911 | After this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, |
| 1912 | with one pair for each predecessor basic block of the current block. Only |
| 1913 | values of <a href="#t_firstclass">first class</a> type may be used as the value |
| 1914 | arguments to the PHI node. Only labels may be used as the label arguments.</p> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1915 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1916 | <p>There must be no non-phi instructions between the start of a basic block and |
| 1917 | the PHI instructions: i.e. PHI instructions must be first in a basic block.</p> |
Chris Lattner | 33ba0d9 | 2001-07-09 00:26:23 +0000 | [diff] [blame] | 1918 | |
| 1919 | <h5>Semantics:</h5> |
| 1920 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1921 | <p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1922 | specified by the parameter, depending on which basic block we came from in the |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1923 | last <a href="#terminators">terminator</a> instruction.</p> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1924 | |
| 1925 | <h5>Example:</h5> |
| 1926 | |
| 1927 | <pre> |
| 1928 | Loop: ; Infinite loop that counts from 0 on up... |
| 1929 | %indvar = phi uint [ 0, %LoopHeader ], [ %nextindvar, %Loop ] |
| 1930 | %nextindvar = add uint %indvar, 1 |
| 1931 | br label %Loop |
| 1932 | </pre> |
| 1933 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1934 | </div> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1935 | |
| 1936 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1937 | <div class="doc_subsubsection"> |
| 1938 | <a name="i_cast">'<tt>cast .. to</tt>' Instruction</a> |
| 1939 | </div> |
| 1940 | |
| 1941 | <div class="doc_text"> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1942 | |
| 1943 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1944 | |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1945 | <pre> |
| 1946 | <result> = cast <ty> <value> to <ty2> <i>; yields ty2</i> |
| 1947 | </pre> |
| 1948 | |
| 1949 | <h5>Overview:</h5> |
| 1950 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1951 | <p>The '<tt>cast</tt>' instruction is used as the primitive means to convert |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1952 | integers to floating point, change data type sizes, and break type safety (by |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1953 | casting pointers).</p> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1954 | |
| 1955 | <h5>Arguments:</h5> |
| 1956 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1957 | <p>The '<tt>cast</tt>' instruction takes a value to cast, which must be a first |
Chris Lattner | 478921b | 2003-10-30 01:31:37 +0000 | [diff] [blame] | 1958 | class value, and a type to cast it to, which must also be a <a |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1959 | href="#t_firstclass">first class</a> type.</p> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1960 | |
| 1961 | <h5>Semantics:</h5> |
| 1962 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1963 | <p>This instruction follows the C rules for explicit casts when determining how |
| 1964 | the data being cast must change to fit in its new container.</p> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1965 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1966 | <p>When casting to bool, any value that would be considered true in the context |
| 1967 | of a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' |
| 1968 | values, all else are '<tt>false</tt>'.</p> |
Chris Lattner | 33ba0d9 | 2001-07-09 00:26:23 +0000 | [diff] [blame] | 1969 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1970 | <p>When extending an integral value from a type of one signness to another (for |
Chris Lattner | f8856bc | 2002-08-13 20:52:09 +0000 | [diff] [blame] | 1971 | example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value is sign-extended if the |
| 1972 | <b>source</b> value is signed, and zero-extended if the source value is |
Chris Lattner | 2b4dcbb | 2002-08-15 19:36:05 +0000 | [diff] [blame] | 1973 | unsigned. <tt>bool</tt> values are always zero extended into either zero or |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1974 | one.</p> |
Chris Lattner | f8856bc | 2002-08-13 20:52:09 +0000 | [diff] [blame] | 1975 | |
Chris Lattner | 33ba0d9 | 2001-07-09 00:26:23 +0000 | [diff] [blame] | 1976 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1977 | |
Chris Lattner | 33ba0d9 | 2001-07-09 00:26:23 +0000 | [diff] [blame] | 1978 | <pre> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1979 | %X = cast int 257 to ubyte <i>; yields ubyte:1</i> |
Chris Lattner | 7bae395 | 2002-06-25 18:03:17 +0000 | [diff] [blame] | 1980 | %Y = cast int 123 to bool <i>; yields bool:true</i> |
Chris Lattner | 33ba0d9 | 2001-07-09 00:26:23 +0000 | [diff] [blame] | 1981 | </pre> |
| 1982 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1983 | </div> |
Chris Lattner | 33ba0d9 | 2001-07-09 00:26:23 +0000 | [diff] [blame] | 1984 | |
| 1985 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1986 | <div class="doc_subsubsection"> |
| 1987 | <a name="i_call">'<tt>call</tt>' Instruction</a> |
| 1988 | </div> |
| 1989 | |
| 1990 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1991 | |
| 1992 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 1993 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1994 | <pre> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1995 | <result> = call <ty>* <fnptrval>(<param list>) |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1996 | </pre> |
| 1997 | |
| 1998 | <h5>Overview:</h5> |
| 1999 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2000 | <p>The '<tt>call</tt>' instruction represents a simple function call.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2001 | |
| 2002 | <h5>Arguments:</h5> |
| 2003 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2004 | <p>This instruction requires several arguments:</p> |
| 2005 | |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 2006 | <ol> |
| 2007 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2008 | <li><p>'<tt>ty</tt>': shall be the signature of the pointer to function value |
| 2009 | being invoked. The argument types must match the types implied by this |
| 2010 | signature.</p></li> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 2011 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2012 | <li><p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function |
| 2013 | to be invoked. In most cases, this is a direct function invocation, but |
| 2014 | indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer to |
| 2015 | function values.</p></li> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 2016 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2017 | <li><p>'<tt>function args</tt>': argument list whose types match the function |
| 2018 | signature argument types. If the function signature indicates the function |
| 2019 | accepts a variable number of arguments, the extra arguments can be |
| 2020 | specified.</p></li> |
| 2021 | |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 2022 | </ol> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2023 | |
| 2024 | <h5>Semantics:</h5> |
| 2025 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2026 | <p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to |
| 2027 | a specified function, with its incoming arguments bound to the specified values. |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 2028 | Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called function, |
| 2029 | control flow continues with the instruction after the function call, and the |
| 2030 | return value of the function is bound to the result argument. This is a simpler |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2031 | case of the <a href="#i_invoke">invoke</a> instruction.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2032 | |
| 2033 | <h5>Example:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2034 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2035 | <pre> |
| 2036 | %retval = call int %test(int %argc) |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 2037 | call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42); |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2038 | </pre> |
| 2039 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2040 | </div> |
| 2041 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2042 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2043 | <div class="doc_subsubsection"> |
| 2044 | <a name="i_vanext">'<tt>vanext</tt>' Instruction</a> |
| 2045 | </div> |
| 2046 | |
| 2047 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2048 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2049 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2050 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2051 | <pre> |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2052 | <resultarglist> = vanext <va_list> <arglist>, <argty> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2053 | </pre> |
| 2054 | |
| 2055 | <h5>Overview:</h5> |
| 2056 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2057 | <p>The '<tt>vanext</tt>' instruction is used to access arguments passed through |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2058 | the "variable argument" area of a function call. It is used to implement the |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2059 | <tt>va_arg</tt> macro in C.</p> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2060 | |
| 2061 | <h5>Arguments:</h5> |
| 2062 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2063 | <p>This instruction takes a <tt>valist</tt> value and the type of the argument. |
| 2064 | It returns another <tt>valist</tt>.</p> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2065 | |
| 2066 | <h5>Semantics:</h5> |
| 2067 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2068 | <p>The '<tt>vanext</tt>' instruction advances the specified <tt>valist</tt> past |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2069 | an argument of the specified type. In conjunction with the <a |
| 2070 | href="#i_vaarg"><tt>vaarg</tt></a> instruction, it is used to implement the |
| 2071 | <tt>va_arg</tt> macro available in C. For more information, see the variable |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2072 | argument handling <a href="#int_varargs">Intrinsic Functions</a>.</p> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2073 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2074 | <p>It is legal for this instruction to be called in a function which does not |
| 2075 | take a variable number of arguments, for example, the <tt>vfprintf</tt> |
| 2076 | function.</p> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2077 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2078 | <p><tt>vanext</tt> is an LLVM instruction instead of an <a |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2079 | href="#intrinsics">intrinsic function</a> because it takes an type as an |
| 2080 | argument.</p> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2081 | |
| 2082 | <h5>Example:</h5> |
| 2083 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2084 | <p>See the <a href="#int_varargs">variable argument processing</a> section.</p> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2085 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2086 | </div> |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2087 | |
| 2088 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2089 | <div class="doc_subsubsection"> |
| 2090 | <a name="i_vaarg">'<tt>vaarg</tt>' Instruction</a> |
| 2091 | </div> |
| 2092 | |
| 2093 | <div class="doc_text"> |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2094 | |
| 2095 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2096 | |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2097 | <pre> |
| 2098 | <resultval> = vaarg <va_list> <arglist>, <argty> |
| 2099 | </pre> |
| 2100 | |
| 2101 | <h5>Overview:</h5> |
| 2102 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2103 | <p>The '<tt>vaarg</tt>' instruction is used to access arguments passed through |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2104 | the "variable argument" area of a function call. It is used to implement the |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2105 | <tt>va_arg</tt> macro in C.</p> |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2106 | |
| 2107 | <h5>Arguments:</h5> |
| 2108 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2109 | <p>This instruction takes a <tt>valist</tt> value and the type of the argument. |
| 2110 | It returns a value of the specified argument type.</p> |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2111 | |
| 2112 | <h5>Semantics:</h5> |
| 2113 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2114 | <p>The '<tt>vaarg</tt>' instruction loads an argument of the specified type from |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2115 | the specified <tt>va_list</tt>. In conjunction with the <a |
| 2116 | href="#i_vanext"><tt>vanext</tt></a> instruction, it is used to implement the |
| 2117 | <tt>va_arg</tt> macro available in C. For more information, see the variable |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2118 | argument handling <a href="#int_varargs">Intrinsic Functions</a>.</p> |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2119 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2120 | <p>It is legal for this instruction to be called in a function which does not |
| 2121 | take a variable number of arguments, for example, the <tt>vfprintf</tt> |
| 2122 | function.</p> |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2123 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2124 | <p><tt>vaarg</tt> is an LLVM instruction instead of an <a |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2125 | href="#intrinsics">intrinsic function</a> because it takes an type as an |
| 2126 | argument.</p> |
| 2127 | |
| 2128 | <h5>Example:</h5> |
| 2129 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2130 | <p>See the <a href="#int_varargs">variable argument processing</a> section.</p> |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2131 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2132 | </div> |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2133 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2134 | <!-- *********************************************************************** --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2135 | <div class="doc_section"> |
| 2136 | <a name="intrinsics">Intrinsic Functions</a> |
| 2137 | </div> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2138 | <!-- *********************************************************************** --> |
| 2139 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2140 | <div class="doc_text"> |
| 2141 | |
| 2142 | <p>LLVM supports the notion of an "intrinsic function". These functions have |
| 2143 | well known names and semantics, and are required to follow certain restrictions. |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2144 | Overall, these instructions represent an extension mechanism for the LLVM |
| 2145 | language that does not require changing all of the transformations in LLVM to |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2146 | add to the language (or the bytecode reader/writer, the parser, etc...).</p> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2147 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2148 | <p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix, this |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2149 | prefix is reserved in LLVM for intrinsic names, thus functions may not be named |
| 2150 | this. Intrinsic functions must always be external functions: you cannot define |
| 2151 | the body of intrinsic functions. Intrinsic functions may only be used in call |
| 2152 | or invoke instructions: it is illegal to take the address of an intrinsic |
| 2153 | function. Additionally, because intrinsic functions are part of the LLVM |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2154 | language, it is required that they all be documented here if any are added.</p> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2155 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2156 | <p>Unless an intrinsic function is target-specific, there must be a lowering |
| 2157 | pass to eliminate the intrinsic or all backends must support the intrinsic |
| 2158 | function.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2159 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2160 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2161 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2162 | <!-- ======================================================================= --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2163 | <div class="doc_subsection"> |
| 2164 | <a name="int_varargs">Variable Argument Handling Intrinsics</a> |
| 2165 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2166 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2167 | <div class="doc_text"> |
| 2168 | |
| 2169 | <p>Variable argument support is defined in LLVM with the <a |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2170 | href="#i_vanext"><tt>vanext</tt></a> instruction and these three intrinsic |
| 2171 | functions. These functions are related to the similarly named macros defined in |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2172 | the <tt><stdarg.h></tt> header file.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2173 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2174 | <p>All of these functions operate on arguments that use a target-specific value |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2175 | type "<tt>va_list</tt>". The LLVM assembly language reference manual does not |
| 2176 | define what this type is, so all transformations should be prepared to handle |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2177 | intrinsics with any type used.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2178 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2179 | <p>This example shows how the <a href="#i_vanext"><tt>vanext</tt></a> |
| 2180 | instruction and the variable argument handling intrinsic functions are used.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2181 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2182 | <pre> |
| 2183 | int %test(int %X, ...) { |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2184 | ; Initialize variable argument processing |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2185 | %ap = call sbyte*()* %<a href="#i_va_start">llvm.va_start</a>() |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2186 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2187 | ; Read a single integer argument |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2188 | %tmp = vaarg sbyte* %ap, int |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2189 | |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2190 | ; Advance to the next argument |
| 2191 | %ap2 = vanext sbyte* %ap, int |
| 2192 | |
| 2193 | ; Demonstrate usage of llvm.va_copy and llvm.va_end |
| 2194 | %aq = call sbyte* (sbyte*)* %<a href="#i_va_copy">llvm.va_copy</a>(sbyte* %ap2) |
| 2195 | call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %aq) |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2196 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2197 | ; Stop processing of arguments. |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2198 | call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %ap2) |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2199 | ret int %tmp |
| 2200 | } |
| 2201 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2202 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2203 | </div> |
| 2204 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2205 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2206 | <div class="doc_subsubsection"> |
| 2207 | <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a> |
| 2208 | </div> |
| 2209 | |
| 2210 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2211 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2212 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2213 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2214 | <pre> |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2215 | call va_list ()* %llvm.va_start() |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2216 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2217 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2218 | <h5>Overview:</h5> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2219 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2220 | <p>The '<tt>llvm.va_start</tt>' intrinsic returns a new <tt><arglist></tt> |
| 2221 | for subsequent use by the variable argument intrinsics.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2222 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2223 | <h5>Semantics:</h5> |
| 2224 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2225 | <p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt> |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2226 | macro available in C. In a target-dependent way, it initializes and returns a |
| 2227 | <tt>va_list</tt> element, so that the next <tt>vaarg</tt> will produce the first |
| 2228 | variable argument passed to the function. Unlike the C <tt>va_start</tt> macro, |
| 2229 | this intrinsic does not need to know the last argument of the function, the |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2230 | compiler can figure that out.</p> |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2231 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2232 | <p>Note that this intrinsic function is only legal to be called from within the |
| 2233 | body of a variable argument function.</p> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2234 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2235 | </div> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2236 | |
| 2237 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2238 | <div class="doc_subsubsection"> |
| 2239 | <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a> |
| 2240 | </div> |
| 2241 | |
| 2242 | <div class="doc_text"> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2243 | |
| 2244 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2245 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2246 | <pre> |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2247 | call void (va_list)* %llvm.va_end(va_list <arglist>) |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2248 | </pre> |
| 2249 | |
| 2250 | <h5>Overview:</h5> |
| 2251 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2252 | <p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt><arglist></tt> which |
| 2253 | has been initialized previously with <tt><a |
Chris Lattner | 2c1bbd8 | 2003-10-21 15:43:55 +0000 | [diff] [blame] | 2254 | href="#i_va_start">llvm.va_start</a></tt> or <tt><a |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2255 | href="#i_va_copy">llvm.va_copy</a></tt>.</p> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2256 | |
| 2257 | <h5>Arguments:</h5> |
| 2258 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2259 | <p>The argument is a <tt>va_list</tt> to destroy.</p> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2260 | |
| 2261 | <h5>Semantics:</h5> |
| 2262 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2263 | <p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt> |
| 2264 | macro available in C. In a target-dependent way, it destroys the |
| 2265 | <tt>va_list</tt>. Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and |
| 2266 | <a href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly with |
| 2267 | calls to <tt>llvm.va_end</tt>.</p> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2268 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2269 | </div> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2270 | |
| 2271 | <!-- _______________________________________________________________________ --> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2272 | <div class="doc_subsubsection"> |
| 2273 | <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a> |
| 2274 | </div> |
| 2275 | |
| 2276 | <div class="doc_text"> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2277 | |
| 2278 | <h5>Syntax:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2279 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2280 | <pre> |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2281 | call va_list (va_list)* %llvm.va_copy(va_list <destarglist>) |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2282 | </pre> |
| 2283 | |
| 2284 | <h5>Overview:</h5> |
| 2285 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2286 | <p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position |
| 2287 | from the source argument list to the destination argument list.</p> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2288 | |
| 2289 | <h5>Arguments:</h5> |
| 2290 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2291 | <p>The argument is the <tt>va_list</tt> to copy.</p> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 2292 | |
| 2293 | <h5>Semantics:</h5> |
| 2294 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2295 | <p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> |
| 2296 | macro available in C. In a target-dependent way, it copies the source |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 2297 | <tt>va_list</tt> element into the returned list. This intrinsic is necessary |
Chris Lattner | 2c1bbd8 | 2003-10-21 15:43:55 +0000 | [diff] [blame] | 2298 | because the <tt><a href="i_va_start">llvm.va_start</a></tt> intrinsic may be |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2299 | arbitrarily complex and require memory allocation, for example.</p> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 2300 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2301 | </div> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 2302 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2303 | <!-- *********************************************************************** --> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2304 | |
| 2305 | <hr> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame^] | 2306 | <div class="doc_footer"> |
| 2307 | <address><a href="mailto:sabre@nondot.org">Chris Lattner</a></address> |
| 2308 | <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a> |
| 2309 | <br> |
| 2310 | Last modified: $Date$ |
| 2311 | </div> |
| 2312 | |
| 2313 | </body> |
| 2314 | </html> |