Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 1 | <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" |
| 2 | "http://www.w3.org/TR/html4/strict.dtd"> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3 | <html> |
| 4 | <head> |
| 5 | <title>LLVM Assembly Language Reference Manual</title> |
Reid Spencer | 3921c74 | 2004-08-26 20:44:00 +0000 | [diff] [blame] | 6 | <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> |
| 7 | <meta name="author" content="Chris Lattner"> |
| 8 | <meta name="description" |
| 9 | content="LLVM Assembly Language Reference Manual."> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 10 | <link rel="stylesheet" href="llvm.css" type="text/css"> |
| 11 | </head> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 12 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 13 | <body> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 14 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 15 | <div class="doc_title"> LLVM Language Reference Manual </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 16 | <ol> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 17 | <li><a href="#abstract">Abstract</a></li> |
| 18 | <li><a href="#introduction">Introduction</a></li> |
| 19 | <li><a href="#identifiers">Identifiers</a></li> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 20 | <li><a href="#highlevel">High Level Structure</a> |
| 21 | <ol> |
| 22 | <li><a href="#modulestructure">Module Structure</a></li> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 23 | <li><a href="#linkage">Linkage Types</a></li> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 24 | <li><a href="#callingconv">Calling Conventions</a></li> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 25 | <li><a href="#globalvars">Global Variables</a></li> |
Chris Lattner | 4e9aba7 | 2006-01-23 23:23:47 +0000 | [diff] [blame] | 26 | <li><a href="#functionstructure">Functions</a></li> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 27 | <li><a href="#paramattrs">Parameter Attributes</a></li> |
Chris Lattner | 4e9aba7 | 2006-01-23 23:23:47 +0000 | [diff] [blame] | 28 | <li><a href="#moduleasm">Module-Level Inline Assembly</a></li> |
Reid Spencer | de15194 | 2007-02-19 23:54:10 +0000 | [diff] [blame] | 29 | <li><a href="#datalayout">Data Layout</a></li> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 30 | </ol> |
| 31 | </li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 32 | <li><a href="#typesystem">Type System</a> |
| 33 | <ol> |
Robert Bocchino | 7b81c75 | 2006-02-17 21:18:08 +0000 | [diff] [blame] | 34 | <li><a href="#t_primitive">Primitive Types</a> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 35 | <ol> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 36 | <li><a href="#t_classifications">Type Classifications</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 37 | </ol> |
| 38 | </li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 39 | <li><a href="#t_derived">Derived Types</a> |
| 40 | <ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 41 | <li><a href="#t_array">Array Type</a></li> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 42 | <li><a href="#t_function">Function Type</a></li> |
| 43 | <li><a href="#t_pointer">Pointer Type</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 44 | <li><a href="#t_struct">Structure Type</a></li> |
Andrew Lenharth | 75e1068 | 2006-12-08 17:13:00 +0000 | [diff] [blame] | 45 | <li><a href="#t_pstruct">Packed Structure Type</a></li> |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 46 | <li><a href="#t_vector">Vector Type</a></li> |
Chris Lattner | 69c11bb | 2005-04-25 17:34:15 +0000 | [diff] [blame] | 47 | <li><a href="#t_opaque">Opaque Type</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 48 | </ol> |
| 49 | </li> |
| 50 | </ol> |
| 51 | </li> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 52 | <li><a href="#constants">Constants</a> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 53 | <ol> |
| 54 | <li><a href="#simpleconstants">Simple Constants</a> |
| 55 | <li><a href="#aggregateconstants">Aggregate Constants</a> |
| 56 | <li><a href="#globalconstants">Global Variable and Function Addresses</a> |
| 57 | <li><a href="#undefvalues">Undefined Values</a> |
| 58 | <li><a href="#constantexprs">Constant Expressions</a> |
| 59 | </ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 60 | </li> |
Chris Lattner | e87d653 | 2006-01-25 23:47:57 +0000 | [diff] [blame] | 61 | <li><a href="#othervalues">Other Values</a> |
| 62 | <ol> |
| 63 | <li><a href="#inlineasm">Inline Assembler Expressions</a> |
| 64 | </ol> |
| 65 | </li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 66 | <li><a href="#instref">Instruction Reference</a> |
| 67 | <ol> |
| 68 | <li><a href="#terminators">Terminator Instructions</a> |
| 69 | <ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 70 | <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li> |
| 71 | <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 72 | <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li> |
| 73 | <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 74 | <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 75 | <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 76 | </ol> |
| 77 | </li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 78 | <li><a href="#binaryops">Binary Operations</a> |
| 79 | <ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 80 | <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li> |
| 81 | <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li> |
| 82 | <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li> |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 83 | <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li> |
| 84 | <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li> |
| 85 | <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li> |
Reid Spencer | 0a783f7 | 2006-11-02 01:53:59 +0000 | [diff] [blame] | 86 | <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li> |
| 87 | <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li> |
| 88 | <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 89 | </ol> |
| 90 | </li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 91 | <li><a href="#bitwiseops">Bitwise Binary Operations</a> |
| 92 | <ol> |
Reid Spencer | 8e11bf8 | 2007-02-02 13:57:07 +0000 | [diff] [blame] | 93 | <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li> |
| 94 | <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li> |
| 95 | <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 96 | <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 97 | <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 98 | <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 99 | </ol> |
| 100 | </li> |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 101 | <li><a href="#vectorops">Vector Operations</a> |
| 102 | <ol> |
| 103 | <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li> |
| 104 | <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li> |
| 105 | <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li> |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 106 | </ol> |
| 107 | </li> |
Chris Lattner | 884a970 | 2006-08-15 00:45:58 +0000 | [diff] [blame] | 108 | <li><a href="#memoryops">Memory Access and Addressing Operations</a> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 109 | <ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 110 | <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li> |
| 111 | <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li> |
| 112 | <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li> |
Robert Bocchino | 7b81c75 | 2006-02-17 21:18:08 +0000 | [diff] [blame] | 113 | <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li> |
| 114 | <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li> |
| 115 | <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 116 | </ol> |
| 117 | </li> |
Reid Spencer | 2fd21e6 | 2006-11-08 01:18:52 +0000 | [diff] [blame] | 118 | <li><a href="#convertops">Conversion Operations</a> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 119 | <ol> |
| 120 | <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li> |
| 121 | <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li> |
| 122 | <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li> |
| 123 | <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li> |
| 124 | <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 125 | <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li> |
| 126 | <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li> |
| 127 | <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li> |
| 128 | <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li> |
Reid Spencer | 7267925 | 2006-11-11 21:00:47 +0000 | [diff] [blame] | 129 | <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li> |
| 130 | <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li> |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 131 | <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 132 | </ol> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 133 | <li><a href="#otherops">Other Operations</a> |
| 134 | <ol> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 135 | <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li> |
| 136 | <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 137 | <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 138 | <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 139 | <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li> |
Chris Lattner | fb6977d | 2006-01-13 23:26:01 +0000 | [diff] [blame] | 140 | <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 141 | </ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 142 | </li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 143 | </ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 144 | </li> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 145 | <li><a href="#intrinsics">Intrinsic Functions</a> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 146 | <ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 147 | <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a> |
| 148 | <ol> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 149 | <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li> |
| 150 | <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li> |
| 151 | <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 152 | </ol> |
| 153 | </li> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 154 | <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a> |
| 155 | <ol> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 156 | <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li> |
| 157 | <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li> |
| 158 | <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 159 | </ol> |
| 160 | </li> |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 161 | <li><a href="#int_codegen">Code Generator Intrinsics</a> |
| 162 | <ol> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 163 | <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li> |
| 164 | <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li> |
| 165 | <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li> |
| 166 | <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li> |
| 167 | <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li> |
| 168 | <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li> |
| 169 | <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li> |
John Criswell | 7123e27 | 2004-04-09 16:43:20 +0000 | [diff] [blame] | 170 | </ol> |
| 171 | </li> |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 172 | <li><a href="#int_libc">Standard C Library Intrinsics</a> |
| 173 | <ol> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 174 | <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li> |
| 175 | <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li> |
| 176 | <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li> |
| 177 | <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li> |
| 178 | <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li> |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 179 | </ol> |
| 180 | </li> |
Nate Begeman | 7e36c47 | 2006-01-13 23:26:38 +0000 | [diff] [blame] | 181 | <li><a href="#int_manip">Bit Manipulation Intrinsics</a> |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 182 | <ol> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 183 | <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li> |
Chris Lattner | 8a886be | 2006-01-16 22:34:14 +0000 | [diff] [blame] | 184 | <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li> |
| 185 | <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li> |
| 186 | <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li> |
Reid Spencer | f86037f | 2007-04-11 23:23:49 +0000 | [diff] [blame] | 187 | <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li> |
| 188 | <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li> |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 189 | </ol> |
| 190 | </li> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 191 | <li><a href="#int_debugger">Debugger intrinsics</a></li> |
Jim Laskey | dd4ef1b | 2007-03-14 19:31:19 +0000 | [diff] [blame] | 192 | <li><a href="#int_eh">Exception Handling intrinsics</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 193 | </ol> |
| 194 | </li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 195 | </ol> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 196 | |
| 197 | <div class="doc_author"> |
| 198 | <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a> |
| 199 | and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 200 | </div> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 201 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 202 | <!-- *********************************************************************** --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 203 | <div class="doc_section"> <a name="abstract">Abstract </a></div> |
| 204 | <!-- *********************************************************************** --> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 205 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 206 | <div class="doc_text"> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 207 | <p>This document is a reference manual for the LLVM assembly language. |
| 208 | LLVM is an SSA based representation that provides type safety, |
| 209 | low-level operations, flexibility, and the capability of representing |
| 210 | 'all' high-level languages cleanly. It is the common code |
| 211 | representation used throughout all phases of the LLVM compilation |
| 212 | strategy.</p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 213 | </div> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 214 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 215 | <!-- *********************************************************************** --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 216 | <div class="doc_section"> <a name="introduction">Introduction</a> </div> |
| 217 | <!-- *********************************************************************** --> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 218 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 219 | <div class="doc_text"> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 220 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 221 | <p>The LLVM code representation is designed to be used in three |
| 222 | different forms: as an in-memory compiler IR, as an on-disk bytecode |
| 223 | representation (suitable for fast loading by a Just-In-Time compiler), |
| 224 | and as a human readable assembly language representation. This allows |
| 225 | LLVM to provide a powerful intermediate representation for efficient |
| 226 | compiler transformations and analysis, while providing a natural means |
| 227 | to debug and visualize the transformations. The three different forms |
| 228 | of LLVM are all equivalent. This document describes the human readable |
| 229 | representation and notation.</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 230 | |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 231 | <p>The LLVM representation aims to be light-weight and low-level |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 232 | while being expressive, typed, and extensible at the same time. It |
| 233 | aims to be a "universal IR" of sorts, by being at a low enough level |
| 234 | that high-level ideas may be cleanly mapped to it (similar to how |
| 235 | microprocessors are "universal IR's", allowing many source languages to |
| 236 | be mapped to them). By providing type information, LLVM can be used as |
| 237 | the target of optimizations: for example, through pointer analysis, it |
| 238 | can be proven that a C automatic variable is never accessed outside of |
| 239 | the current function... allowing it to be promoted to a simple SSA |
| 240 | value instead of a memory location.</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 241 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 242 | </div> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 243 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 244 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 245 | <div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 246 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 247 | <div class="doc_text"> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 248 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 249 | <p>It is important to note that this document describes 'well formed' |
| 250 | LLVM assembly language. There is a difference between what the parser |
| 251 | accepts and what is considered 'well formed'. For example, the |
| 252 | following instruction is syntactically okay, but not well formed:</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 253 | |
| 254 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 255 | %x = <a href="#i_add">add</a> i32 1, %x |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 256 | </pre> |
| 257 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 258 | <p>...because the definition of <tt>%x</tt> does not dominate all of |
| 259 | its uses. The LLVM infrastructure provides a verification pass that may |
| 260 | be used to verify that an LLVM module is well formed. This pass is |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 261 | automatically run by the parser after parsing input assembly and by |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 262 | the optimizer before it outputs bytecode. The violations pointed out |
| 263 | by the verifier pass indicate bugs in transformation passes or input to |
| 264 | the parser.</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 265 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 266 | <!-- Describe the typesetting conventions here. --> </div> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 267 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 268 | <!-- *********************************************************************** --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 269 | <div class="doc_section"> <a name="identifiers">Identifiers</a> </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 270 | <!-- *********************************************************************** --> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 271 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 272 | <div class="doc_text"> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 273 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 274 | <p>LLVM uses three different forms of identifiers, for different |
| 275 | purposes:</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 276 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 277 | <ol> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 278 | <li>Named values are represented as a string of characters with a '%' prefix. |
| 279 | For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual |
| 280 | regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. |
| 281 | Identifiers which require other characters in their names can be surrounded |
Anton Korobeynikov | 7f70559 | 2007-01-12 19:20:47 +0000 | [diff] [blame] | 282 | with quotes. In this way, anything except a <tt>"</tt> character can be used |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 283 | in a name.</li> |
| 284 | |
| 285 | <li>Unnamed values are represented as an unsigned numeric value with a '%' |
| 286 | prefix. For example, %12, %2, %44.</li> |
| 287 | |
Reid Spencer | cc16dc3 | 2004-12-09 18:02:53 +0000 | [diff] [blame] | 288 | <li>Constants, which are described in a <a href="#constants">section about |
| 289 | constants</a>, below.</li> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 290 | </ol> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 291 | |
| 292 | <p>LLVM requires that values start with a '%' sign for two reasons: Compilers |
| 293 | don't need to worry about name clashes with reserved words, and the set of |
| 294 | reserved words may be expanded in the future without penalty. Additionally, |
| 295 | unnamed identifiers allow a compiler to quickly come up with a temporary |
| 296 | variable without having to avoid symbol table conflicts.</p> |
| 297 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 298 | <p>Reserved words in LLVM are very similar to reserved words in other |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 299 | languages. There are keywords for different opcodes |
| 300 | ('<tt><a href="#i_add">add</a></tt>', |
| 301 | '<tt><a href="#i_bitcast">bitcast</a></tt>', |
| 302 | '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 303 | href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...), |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 304 | and others. These reserved words cannot conflict with variable names, because |
| 305 | none of them start with a '%' character.</p> |
| 306 | |
| 307 | <p>Here is an example of LLVM code to multiply the integer variable |
| 308 | '<tt>%X</tt>' by 8:</p> |
| 309 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 310 | <p>The easy way:</p> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 311 | |
| 312 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 313 | %result = <a href="#i_mul">mul</a> i32 %X, 8 |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 314 | </pre> |
| 315 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 316 | <p>After strength reduction:</p> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 317 | |
| 318 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 319 | %result = <a href="#i_shl">shl</a> i32 %X, i8 3 |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 320 | </pre> |
| 321 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 322 | <p>And the hard way:</p> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 323 | |
| 324 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 325 | <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i> |
| 326 | <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i> |
| 327 | %result = <a href="#i_add">add</a> i32 %1, %1 |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 328 | </pre> |
| 329 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 330 | <p>This last way of multiplying <tt>%X</tt> by 8 illustrates several |
| 331 | important lexical features of LLVM:</p> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 332 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 333 | <ol> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 334 | |
| 335 | <li>Comments are delimited with a '<tt>;</tt>' and go until the end of |
| 336 | line.</li> |
| 337 | |
| 338 | <li>Unnamed temporaries are created when the result of a computation is not |
| 339 | assigned to a named value.</li> |
| 340 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 341 | <li>Unnamed temporaries are numbered sequentially</li> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 342 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 343 | </ol> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 344 | |
John Criswell | e4c57cc | 2005-05-12 16:52:32 +0000 | [diff] [blame] | 345 | <p>...and it also shows a convention that we follow in this document. When |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 346 | demonstrating instructions, we will follow an instruction with a comment that |
| 347 | defines the type and name of value produced. Comments are shown in italic |
| 348 | text.</p> |
| 349 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 350 | </div> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 351 | |
| 352 | <!-- *********************************************************************** --> |
| 353 | <div class="doc_section"> <a name="highlevel">High Level Structure</a> </div> |
| 354 | <!-- *********************************************************************** --> |
| 355 | |
| 356 | <!-- ======================================================================= --> |
| 357 | <div class="doc_subsection"> <a name="modulestructure">Module Structure</a> |
| 358 | </div> |
| 359 | |
| 360 | <div class="doc_text"> |
| 361 | |
| 362 | <p>LLVM programs are composed of "Module"s, each of which is a |
| 363 | translation unit of the input programs. Each module consists of |
| 364 | functions, global variables, and symbol table entries. Modules may be |
| 365 | combined together with the LLVM linker, which merges function (and |
| 366 | global variable) definitions, resolves forward declarations, and merges |
| 367 | symbol table entries. Here is an example of the "hello world" module:</p> |
| 368 | |
| 369 | <pre><i>; Declare the string constant as a global constant...</i> |
| 370 | <a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 371 | href="#globalvars">constant</a> <a href="#t_array">[13 x i8 ]</a> c"hello world\0A\00" <i>; [13 x i8 ]*</i> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 372 | |
| 373 | <i>; External declaration of the puts function</i> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 374 | <a href="#functionstructure">declare</a> i32 %puts(i8 *) <i>; i32(i8 *)* </i> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 375 | |
| 376 | <i>; Definition of main function</i> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 377 | define i32 %main() { <i>; i32()* </i> |
| 378 | <i>; Convert [13x i8 ]* to i8 *...</i> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 379 | %cast210 = <a |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 380 | href="#i_getelementptr">getelementptr</a> [13 x i8 ]* %.LC0, i64 0, i64 0 <i>; i8 *</i> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 381 | |
| 382 | <i>; Call puts function to write out the string to stdout...</i> |
| 383 | <a |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 384 | href="#i_call">call</a> i32 %puts(i8 * %cast210) <i>; i32</i> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 385 | <a |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 386 | href="#i_ret">ret</a> i32 0<br>}<br></pre> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 387 | |
| 388 | <p>This example is made up of a <a href="#globalvars">global variable</a> |
| 389 | named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" |
| 390 | function, and a <a href="#functionstructure">function definition</a> |
| 391 | for "<tt>main</tt>".</p> |
| 392 | |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 393 | <p>In general, a module is made up of a list of global values, |
| 394 | where both functions and global variables are global values. Global values are |
| 395 | represented by a pointer to a memory location (in this case, a pointer to an |
| 396 | array of char, and a pointer to a function), and have one of the following <a |
| 397 | href="#linkage">linkage types</a>.</p> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 398 | |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 399 | </div> |
| 400 | |
| 401 | <!-- ======================================================================= --> |
| 402 | <div class="doc_subsection"> |
| 403 | <a name="linkage">Linkage Types</a> |
| 404 | </div> |
| 405 | |
| 406 | <div class="doc_text"> |
| 407 | |
| 408 | <p> |
| 409 | All Global Variables and Functions have one of the following types of linkage: |
| 410 | </p> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 411 | |
| 412 | <dl> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 413 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 414 | <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 415 | |
| 416 | <dd>Global values with internal linkage are only directly accessible by |
| 417 | objects in the current module. In particular, linking code into a module with |
| 418 | an internal global value may cause the internal to be renamed as necessary to |
| 419 | avoid collisions. Because the symbol is internal to the module, all |
| 420 | references can be updated. This corresponds to the notion of the |
Chris Lattner | 4887bd8 | 2007-01-14 06:51:48 +0000 | [diff] [blame] | 421 | '<tt>static</tt>' keyword in C. |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 422 | </dd> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 423 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 424 | <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 425 | |
Chris Lattner | 4887bd8 | 2007-01-14 06:51:48 +0000 | [diff] [blame] | 426 | <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of |
| 427 | the same name when linkage occurs. This is typically used to implement |
| 428 | inline functions, templates, or other code which must be generated in each |
| 429 | translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are |
| 430 | allowed to be discarded. |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 431 | </dd> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 432 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 433 | <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 434 | |
| 435 | <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage, |
| 436 | except that unreferenced <tt>weak</tt> globals may not be discarded. This is |
Chris Lattner | 4887bd8 | 2007-01-14 06:51:48 +0000 | [diff] [blame] | 437 | used for globals that may be emitted in multiple translation units, but that |
| 438 | are not guaranteed to be emitted into every translation unit that uses them. |
| 439 | One example of this are common globals in C, such as "<tt>int X;</tt>" at |
| 440 | global scope. |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 441 | </dd> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 442 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 443 | <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 444 | |
| 445 | <dd>"<tt>appending</tt>" linkage may only be applied to global variables of |
| 446 | pointer to array type. When two global variables with appending linkage are |
| 447 | linked together, the two global arrays are appended together. This is the |
| 448 | LLVM, typesafe, equivalent of having the system linker append together |
| 449 | "sections" with identical names when .o files are linked. |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 450 | </dd> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 451 | |
Anton Korobeynikov | 7f70559 | 2007-01-12 19:20:47 +0000 | [diff] [blame] | 452 | <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt> |
| 453 | <dd>The semantics of this linkage follow the ELF model: the symbol is weak |
| 454 | until linked, if not linked, the symbol becomes null instead of being an |
| 455 | undefined reference. |
| 456 | </dd> |
Anton Korobeynikov | 7f70559 | 2007-01-12 19:20:47 +0000 | [diff] [blame] | 457 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 458 | <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 459 | |
| 460 | <dd>If none of the above identifiers are used, the global is externally |
| 461 | visible, meaning that it participates in linkage and can be used to resolve |
| 462 | external symbol references. |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 463 | </dd> |
Reid Spencer | c891084 | 2007-04-11 23:49:50 +0000 | [diff] [blame] | 464 | </dl> |
Anton Korobeynikov | b74ed07 | 2006-09-14 18:23:27 +0000 | [diff] [blame] | 465 | |
Anton Korobeynikov | b74ed07 | 2006-09-14 18:23:27 +0000 | [diff] [blame] | 466 | <p> |
| 467 | The next two types of linkage are targeted for Microsoft Windows platform |
| 468 | only. They are designed to support importing (exporting) symbols from (to) |
| 469 | DLLs. |
| 470 | </p> |
| 471 | |
Anton Korobeynikov | 7f70559 | 2007-01-12 19:20:47 +0000 | [diff] [blame] | 472 | <dl> |
Anton Korobeynikov | b74ed07 | 2006-09-14 18:23:27 +0000 | [diff] [blame] | 473 | <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt> |
| 474 | |
| 475 | <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function |
| 476 | or variable via a global pointer to a pointer that is set up by the DLL |
| 477 | exporting the symbol. On Microsoft Windows targets, the pointer name is |
| 478 | formed by combining <code>_imp__</code> and the function or variable name. |
| 479 | </dd> |
| 480 | |
| 481 | <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt> |
| 482 | |
| 483 | <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global |
| 484 | pointer to a pointer in a DLL, so that it can be referenced with the |
| 485 | <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer |
| 486 | name is formed by combining <code>_imp__</code> and the function or variable |
| 487 | name. |
| 488 | </dd> |
| 489 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 490 | </dl> |
| 491 | |
Anton Korobeynikov | 7f70559 | 2007-01-12 19:20:47 +0000 | [diff] [blame] | 492 | <p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>" |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 493 | variable is defined to be internal, if another module defined a "<tt>.LC0</tt>" |
| 494 | variable and was linked with this one, one of the two would be renamed, |
| 495 | preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are |
| 496 | external (i.e., lacking any linkage declarations), they are accessible |
Reid Spencer | ac8d276 | 2007-01-05 00:59:10 +0000 | [diff] [blame] | 497 | outside of the current module.</p> |
| 498 | <p>It is illegal for a function <i>declaration</i> |
| 499 | to have any linkage type other than "externally visible", <tt>dllimport</tt>, |
Anton Korobeynikov | 7f70559 | 2007-01-12 19:20:47 +0000 | [diff] [blame] | 500 | or <tt>extern_weak</tt>.</p> |
Anton Korobeynikov | 8b0a8c8 | 2007-04-25 14:27:10 +0000 | [diff] [blame^] | 501 | <p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt> |
| 502 | linkages. |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 503 | </div> |
| 504 | |
| 505 | <!-- ======================================================================= --> |
| 506 | <div class="doc_subsection"> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 507 | <a name="callingconv">Calling Conventions</a> |
| 508 | </div> |
| 509 | |
| 510 | <div class="doc_text"> |
| 511 | |
| 512 | <p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a> |
| 513 | and <a href="#i_invoke">invokes</a> can all have an optional calling convention |
| 514 | specified for the call. The calling convention of any pair of dynamic |
| 515 | caller/callee must match, or the behavior of the program is undefined. The |
| 516 | following calling conventions are supported by LLVM, and more may be added in |
| 517 | the future:</p> |
| 518 | |
| 519 | <dl> |
| 520 | <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt> |
| 521 | |
| 522 | <dd>This calling convention (the default if no other calling convention is |
| 523 | specified) matches the target C calling conventions. This calling convention |
John Criswell | e4c57cc | 2005-05-12 16:52:32 +0000 | [diff] [blame] | 524 | supports varargs function calls and tolerates some mismatch in the declared |
Reid Spencer | c28d2bc | 2006-12-31 21:30:18 +0000 | [diff] [blame] | 525 | prototype and implemented declaration of the function (as does normal C). |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 526 | </dd> |
| 527 | |
| 528 | <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt> |
| 529 | |
| 530 | <dd>This calling convention attempts to make calls as fast as possible |
| 531 | (e.g. by passing things in registers). This calling convention allows the |
| 532 | target to use whatever tricks it wants to produce fast code for the target, |
Chris Lattner | 8cdc5bc | 2005-05-06 23:08:23 +0000 | [diff] [blame] | 533 | without having to conform to an externally specified ABI. Implementations of |
| 534 | this convention should allow arbitrary tail call optimization to be supported. |
| 535 | This calling convention does not support varargs and requires the prototype of |
| 536 | all callees to exactly match the prototype of the function definition. |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 537 | </dd> |
| 538 | |
| 539 | <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt> |
| 540 | |
| 541 | <dd>This calling convention attempts to make code in the caller as efficient |
| 542 | as possible under the assumption that the call is not commonly executed. As |
| 543 | such, these calls often preserve all registers so that the call does not break |
| 544 | any live ranges in the caller side. This calling convention does not support |
| 545 | varargs and requires the prototype of all callees to exactly match the |
| 546 | prototype of the function definition. |
| 547 | </dd> |
| 548 | |
Chris Lattner | cfe6b37 | 2005-05-07 01:46:40 +0000 | [diff] [blame] | 549 | <dt><b>"<tt>cc <<em>n</em>></tt>" - Numbered convention</b>:</dt> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 550 | |
| 551 | <dd>Any calling convention may be specified by number, allowing |
| 552 | target-specific calling conventions to be used. Target specific calling |
| 553 | conventions start at 64. |
| 554 | </dd> |
Chris Lattner | cfe6b37 | 2005-05-07 01:46:40 +0000 | [diff] [blame] | 555 | </dl> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 556 | |
| 557 | <p>More calling conventions can be added/defined on an as-needed basis, to |
| 558 | support pascal conventions or any other well-known target-independent |
| 559 | convention.</p> |
| 560 | |
| 561 | </div> |
| 562 | |
| 563 | <!-- ======================================================================= --> |
| 564 | <div class="doc_subsection"> |
Anton Korobeynikov | 8cea37b | 2007-01-23 12:35:46 +0000 | [diff] [blame] | 565 | <a name="visibility">Visibility Styles</a> |
| 566 | </div> |
| 567 | |
| 568 | <div class="doc_text"> |
| 569 | |
| 570 | <p> |
| 571 | All Global Variables and Functions have one of the following visibility styles: |
| 572 | </p> |
| 573 | |
| 574 | <dl> |
| 575 | <dt><b>"<tt>default</tt>" - Default style</b>:</dt> |
| 576 | |
| 577 | <dd>On ELF, default visibility means that the declaration is visible to other |
| 578 | modules and, in shared libraries, means that the declared entity may be |
| 579 | overridden. On Darwin, default visibility means that the declaration is |
| 580 | visible to other modules. Default visibility corresponds to "external |
| 581 | linkage" in the language. |
| 582 | </dd> |
| 583 | |
| 584 | <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt> |
| 585 | |
| 586 | <dd>Two declarations of an object with hidden visibility refer to the same |
| 587 | object if they are in the same shared object. Usually, hidden visibility |
| 588 | indicates that the symbol will not be placed into the dynamic symbol table, |
| 589 | so no other module (executable or shared library) can reference it |
| 590 | directly. |
| 591 | </dd> |
| 592 | |
| 593 | </dl> |
| 594 | |
| 595 | </div> |
| 596 | |
| 597 | <!-- ======================================================================= --> |
| 598 | <div class="doc_subsection"> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 599 | <a name="globalvars">Global Variables</a> |
| 600 | </div> |
| 601 | |
| 602 | <div class="doc_text"> |
| 603 | |
Chris Lattner | 3689a34 | 2005-02-12 19:30:21 +0000 | [diff] [blame] | 604 | <p>Global variables define regions of memory allocated at compilation time |
Chris Lattner | 88f6c46 | 2005-11-12 00:45:07 +0000 | [diff] [blame] | 605 | instead of run-time. Global variables may optionally be initialized, may have |
Anton Korobeynikov | 8b0a8c8 | 2007-04-25 14:27:10 +0000 | [diff] [blame^] | 606 | an explicit section to be placed in, and may have an optional explicit alignment |
| 607 | specified. A variable may be defined as "thread_local", which means that it |
| 608 | will not be shared by threads (each thread will have a separated copy of the |
| 609 | variable). A variable may be defined as a global "constant," which indicates |
| 610 | that the contents of the variable will <b>never</b> be modified (enabling better |
Chris Lattner | 3689a34 | 2005-02-12 19:30:21 +0000 | [diff] [blame] | 611 | optimization, allowing the global data to be placed in the read-only section of |
| 612 | an executable, etc). Note that variables that need runtime initialization |
John Criswell | 0ec250c | 2005-10-24 16:17:18 +0000 | [diff] [blame] | 613 | cannot be marked "constant" as there is a store to the variable.</p> |
Chris Lattner | 3689a34 | 2005-02-12 19:30:21 +0000 | [diff] [blame] | 614 | |
| 615 | <p> |
| 616 | LLVM explicitly allows <em>declarations</em> of global variables to be marked |
| 617 | constant, even if the final definition of the global is not. This capability |
| 618 | can be used to enable slightly better optimization of the program, but requires |
| 619 | the language definition to guarantee that optimizations based on the |
| 620 | 'constantness' are valid for the translation units that do not include the |
| 621 | definition. |
| 622 | </p> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 623 | |
| 624 | <p>As SSA values, global variables define pointer values that are in |
| 625 | scope (i.e. they dominate) all basic blocks in the program. Global |
| 626 | variables always define a pointer to their "content" type because they |
| 627 | describe a region of memory, and all memory objects in LLVM are |
| 628 | accessed through pointers.</p> |
| 629 | |
Chris Lattner | 88f6c46 | 2005-11-12 00:45:07 +0000 | [diff] [blame] | 630 | <p>LLVM allows an explicit section to be specified for globals. If the target |
| 631 | supports it, it will emit globals to the section specified.</p> |
| 632 | |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 633 | <p>An explicit alignment may be specified for a global. If not present, or if |
| 634 | the alignment is set to zero, the alignment of the global is set by the target |
| 635 | to whatever it feels convenient. If an explicit alignment is specified, the |
| 636 | global is forced to have at least that much alignment. All alignments must be |
| 637 | a power of 2.</p> |
| 638 | |
Chris Lattner | 68027ea | 2007-01-14 00:27:09 +0000 | [diff] [blame] | 639 | <p>For example, the following defines a global with an initializer, section, |
| 640 | and alignment:</p> |
| 641 | |
| 642 | <pre> |
| 643 | %G = constant float 1.0, section "foo", align 4 |
| 644 | </pre> |
| 645 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 646 | </div> |
| 647 | |
| 648 | |
| 649 | <!-- ======================================================================= --> |
| 650 | <div class="doc_subsection"> |
| 651 | <a name="functionstructure">Functions</a> |
| 652 | </div> |
| 653 | |
| 654 | <div class="doc_text"> |
| 655 | |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 656 | <p>LLVM function definitions consist of the "<tt>define</tt>" keyord, |
| 657 | an optional <a href="#linkage">linkage type</a>, an optional |
Anton Korobeynikov | 8cea37b | 2007-01-23 12:35:46 +0000 | [diff] [blame] | 658 | <a href="#visibility">visibility style</a>, an optional |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 659 | <a href="#callingconv">calling convention</a>, a return type, an optional |
| 660 | <a href="#paramattrs">parameter attribute</a> for the return type, a function |
| 661 | name, a (possibly empty) argument list (each with optional |
Anton Korobeynikov | 8cea37b | 2007-01-23 12:35:46 +0000 | [diff] [blame] | 662 | <a href="#paramattrs">parameter attributes</a>), an optional section, an |
| 663 | optional alignment, an opening curly brace, a list of basic blocks, and a |
| 664 | closing curly brace. |
| 665 | |
| 666 | LLVM function declarations consist of the "<tt>declare</tt>" keyword, an |
| 667 | optional <a href="#linkage">linkage type</a>, an optional |
| 668 | <a href="#visibility">visibility style</a>, an optional |
| 669 | <a href="#callingconv">calling convention</a>, a return type, an optional |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 670 | <a href="#paramattrs">parameter attribute</a> for the return type, a function |
| 671 | name, a possibly empty list of arguments, and an optional alignment.</p> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 672 | |
| 673 | <p>A function definition contains a list of basic blocks, forming the CFG for |
| 674 | the function. Each basic block may optionally start with a label (giving the |
| 675 | basic block a symbol table entry), contains a list of instructions, and ends |
| 676 | with a <a href="#terminators">terminator</a> instruction (such as a branch or |
| 677 | function return).</p> |
| 678 | |
John Criswell | e4c57cc | 2005-05-12 16:52:32 +0000 | [diff] [blame] | 679 | <p>The first basic block in a program is special in two ways: it is immediately |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 680 | executed on entrance to the function, and it is not allowed to have predecessor |
| 681 | basic blocks (i.e. there can not be any branches to the entry block of a |
| 682 | function). Because the block can have no predecessors, it also cannot have any |
| 683 | <a href="#i_phi">PHI nodes</a>.</p> |
| 684 | |
| 685 | <p>LLVM functions are identified by their name and type signature. Hence, two |
| 686 | functions with the same name but different parameter lists or return values are |
Chris Lattner | d4f6b17 | 2005-03-07 22:13:59 +0000 | [diff] [blame] | 687 | considered different functions, and LLVM will resolve references to each |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 688 | appropriately.</p> |
| 689 | |
Chris Lattner | 88f6c46 | 2005-11-12 00:45:07 +0000 | [diff] [blame] | 690 | <p>LLVM allows an explicit section to be specified for functions. If the target |
| 691 | supports it, it will emit functions to the section specified.</p> |
| 692 | |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 693 | <p>An explicit alignment may be specified for a function. If not present, or if |
| 694 | the alignment is set to zero, the alignment of the function is set by the target |
| 695 | to whatever it feels convenient. If an explicit alignment is specified, the |
| 696 | function is forced to have at least that much alignment. All alignments must be |
| 697 | a power of 2.</p> |
| 698 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 699 | </div> |
| 700 | |
Anton Korobeynikov | 8b0a8c8 | 2007-04-25 14:27:10 +0000 | [diff] [blame^] | 701 | |
| 702 | <!-- ======================================================================= --> |
| 703 | <div class="doc_subsection"> |
| 704 | <a name="aliasstructure">Aliases</a> |
| 705 | </div> |
| 706 | <div class="doc_text"> |
| 707 | <p>Aliases act as "second name" for the aliasee value (which can be either |
| 708 | function or global variable). Aliases may have an |
| 709 | optional <a href="#linkage">linkage type</a>, and an |
| 710 | optional <a href="#visibility">visibility style</a>.</p> |
| 711 | |
| 712 | <h5>Syntax:</h5> |
| 713 | |
| 714 | <pre> |
| 715 | @<Name> = [Linkage] [Visibility] alias <AliaseeTy> @<Aliasee> |
| 716 | </pre> |
| 717 | |
| 718 | </div> |
| 719 | |
| 720 | |
| 721 | |
Chris Lattner | 4e9aba7 | 2006-01-23 23:23:47 +0000 | [diff] [blame] | 722 | <!-- ======================================================================= --> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 723 | <div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div> |
| 724 | <div class="doc_text"> |
| 725 | <p>The return type and each parameter of a function type may have a set of |
| 726 | <i>parameter attributes</i> associated with them. Parameter attributes are |
| 727 | used to communicate additional information about the result or parameters of |
| 728 | a function. Parameter attributes are considered to be part of the function |
| 729 | type so two functions types that differ only by the parameter attributes |
| 730 | are different function types.</p> |
| 731 | |
Reid Spencer | 950e9f8 | 2007-01-15 18:27:39 +0000 | [diff] [blame] | 732 | <p>Parameter attributes are simple keywords that follow the type specified. If |
| 733 | multiple parameter attributes are needed, they are space separated. For |
Anton Korobeynikov | 7f70559 | 2007-01-12 19:20:47 +0000 | [diff] [blame] | 734 | example:</p><pre> |
Reid Spencer | 950e9f8 | 2007-01-15 18:27:39 +0000 | [diff] [blame] | 735 | %someFunc = i16 (i8 sext %someParam) zext |
| 736 | %someFunc = i16 (i8 zext %someParam) zext</pre> |
Anton Korobeynikov | 7f70559 | 2007-01-12 19:20:47 +0000 | [diff] [blame] | 737 | <p>Note that the two function types above are unique because the parameter has |
Reid Spencer | 950e9f8 | 2007-01-15 18:27:39 +0000 | [diff] [blame] | 738 | a different attribute (sext in the first one, zext in the second). Also note |
| 739 | that the attribute for the function result (zext) comes immediately after the |
| 740 | argument list.</p> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 741 | |
Anton Korobeynikov | 7f70559 | 2007-01-12 19:20:47 +0000 | [diff] [blame] | 742 | <p>Currently, only the following parameter attributes are defined:</p> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 743 | <dl> |
Reid Spencer | 950e9f8 | 2007-01-15 18:27:39 +0000 | [diff] [blame] | 744 | <dt><tt>zext</tt></dt> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 745 | <dd>This indicates that the parameter should be zero extended just before |
| 746 | a call to this function.</dd> |
Reid Spencer | 950e9f8 | 2007-01-15 18:27:39 +0000 | [diff] [blame] | 747 | <dt><tt>sext</tt></dt> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 748 | <dd>This indicates that the parameter should be sign extended just before |
| 749 | a call to this function.</dd> |
Anton Korobeynikov | 34d6dea | 2007-01-28 14:30:45 +0000 | [diff] [blame] | 750 | <dt><tt>inreg</tt></dt> |
| 751 | <dd>This indicates that the parameter should be placed in register (if |
Anton Korobeynikov | 66a8c8c | 2007-01-28 15:27:21 +0000 | [diff] [blame] | 752 | possible) during assembling function call. Support for this attribute is |
| 753 | target-specific</dd> |
Anton Korobeynikov | 34d6dea | 2007-01-28 14:30:45 +0000 | [diff] [blame] | 754 | <dt><tt>sret</tt></dt> |
Anton Korobeynikov | 66a8c8c | 2007-01-28 15:27:21 +0000 | [diff] [blame] | 755 | <dd>This indicates that the parameter specifies the address of a structure |
Reid Spencer | 6760612 | 2007-03-22 02:02:11 +0000 | [diff] [blame] | 756 | that is the return value of the function in the source program.</dd> |
Reid Spencer | 2dc5201 | 2007-03-22 02:18:56 +0000 | [diff] [blame] | 757 | <dt><tt>noreturn</tt></dt> |
| 758 | <dd>This function attribute indicates that the function never returns. This |
| 759 | indicates to LLVM that every call to this function should be treated as if |
| 760 | an <tt>unreachable</tt> instruction immediately followed the call.</dd> |
Reid Spencer | 6760612 | 2007-03-22 02:02:11 +0000 | [diff] [blame] | 761 | <dt><tt>nounwind</tt></dt> |
| 762 | <dd>This function attribute indicates that the function type does not use |
| 763 | the unwind instruction and does not allow stack unwinding to propagate |
| 764 | through it.</dd> |
Anton Korobeynikov | 7f70559 | 2007-01-12 19:20:47 +0000 | [diff] [blame] | 765 | </dl> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 766 | |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 767 | </div> |
| 768 | |
| 769 | <!-- ======================================================================= --> |
Chris Lattner | 4e9aba7 | 2006-01-23 23:23:47 +0000 | [diff] [blame] | 770 | <div class="doc_subsection"> |
Chris Lattner | 1eeeb0c | 2006-04-08 04:40:53 +0000 | [diff] [blame] | 771 | <a name="moduleasm">Module-Level Inline Assembly</a> |
Chris Lattner | 4e9aba7 | 2006-01-23 23:23:47 +0000 | [diff] [blame] | 772 | </div> |
| 773 | |
| 774 | <div class="doc_text"> |
| 775 | <p> |
| 776 | Modules may contain "module-level inline asm" blocks, which corresponds to the |
| 777 | GCC "file scope inline asm" blocks. These blocks are internally concatenated by |
| 778 | LLVM and treated as a single unit, but may be separated in the .ll file if |
| 779 | desired. The syntax is very simple: |
| 780 | </p> |
| 781 | |
| 782 | <div class="doc_code"><pre> |
Chris Lattner | 52599e1 | 2006-01-24 00:37:20 +0000 | [diff] [blame] | 783 | module asm "inline asm code goes here" |
| 784 | module asm "more can go here" |
Chris Lattner | 4e9aba7 | 2006-01-23 23:23:47 +0000 | [diff] [blame] | 785 | </pre></div> |
| 786 | |
| 787 | <p>The strings can contain any character by escaping non-printable characters. |
| 788 | The escape sequence used is simply "\xx" where "xx" is the two digit hex code |
| 789 | for the number. |
| 790 | </p> |
| 791 | |
| 792 | <p> |
| 793 | The inline asm code is simply printed to the machine code .s file when |
| 794 | assembly code is generated. |
| 795 | </p> |
| 796 | </div> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 797 | |
Reid Spencer | de15194 | 2007-02-19 23:54:10 +0000 | [diff] [blame] | 798 | <!-- ======================================================================= --> |
| 799 | <div class="doc_subsection"> |
| 800 | <a name="datalayout">Data Layout</a> |
| 801 | </div> |
| 802 | |
| 803 | <div class="doc_text"> |
| 804 | <p>A module may specify a target specific data layout string that specifies how |
Reid Spencer | c891084 | 2007-04-11 23:49:50 +0000 | [diff] [blame] | 805 | data is to be laid out in memory. The syntax for the data layout is simply:</p> |
| 806 | <pre> target datalayout = "<i>layout specification</i>"</pre> |
| 807 | <p>The <i>layout specification</i> consists of a list of specifications |
| 808 | separated by the minus sign character ('-'). Each specification starts with a |
| 809 | letter and may include other information after the letter to define some |
| 810 | aspect of the data layout. The specifications accepted are as follows: </p> |
Reid Spencer | de15194 | 2007-02-19 23:54:10 +0000 | [diff] [blame] | 811 | <dl> |
| 812 | <dt><tt>E</tt></dt> |
| 813 | <dd>Specifies that the target lays out data in big-endian form. That is, the |
| 814 | bits with the most significance have the lowest address location.</dd> |
| 815 | <dt><tt>e</tt></dt> |
| 816 | <dd>Specifies that hte target lays out data in little-endian form. That is, |
| 817 | the bits with the least significance have the lowest address location.</dd> |
| 818 | <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt> |
| 819 | <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and |
| 820 | <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i> |
| 821 | alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted |
| 822 | too.</dd> |
| 823 | <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt> |
| 824 | <dd>This specifies the alignment for an integer type of a given bit |
| 825 | <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd> |
| 826 | <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt> |
| 827 | <dd>This specifies the alignment for a vector type of a given bit |
| 828 | <i>size</i>.</dd> |
| 829 | <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt> |
| 830 | <dd>This specifies the alignment for a floating point type of a given bit |
| 831 | <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64 |
| 832 | (double).</dd> |
| 833 | <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt> |
| 834 | <dd>This specifies the alignment for an aggregate type of a given bit |
| 835 | <i>size</i>.</dd> |
| 836 | </dl> |
| 837 | <p>When constructing the data layout for a given target, LLVM starts with a |
| 838 | default set of specifications which are then (possibly) overriden by the |
| 839 | specifications in the <tt>datalayout</tt> keyword. The default specifications |
| 840 | are given in this list:</p> |
| 841 | <ul> |
| 842 | <li><tt>E</tt> - big endian</li> |
| 843 | <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li> |
| 844 | <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li> |
| 845 | <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li> |
| 846 | <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li> |
| 847 | <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li> |
| 848 | <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred |
| 849 | alignment of 64-bits</li> |
| 850 | <li><tt>f32:32:32</tt> - float is 32-bit aligned</li> |
| 851 | <li><tt>f64:64:64</tt> - double is 64-bit aligned</li> |
| 852 | <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li> |
| 853 | <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li> |
| 854 | <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li> |
| 855 | </ul> |
| 856 | <p>When llvm is determining the alignment for a given type, it uses the |
| 857 | following rules: |
| 858 | <ol> |
| 859 | <li>If the type sought is an exact match for one of the specifications, that |
| 860 | specification is used.</li> |
| 861 | <li>If no match is found, and the type sought is an integer type, then the |
| 862 | smallest integer type that is larger than the bitwidth of the sought type is |
| 863 | used. If none of the specifications are larger than the bitwidth then the the |
| 864 | largest integer type is used. For example, given the default specifications |
| 865 | above, the i7 type will use the alignment of i8 (next largest) while both |
| 866 | i65 and i256 will use the alignment of i64 (largest specified).</li> |
| 867 | <li>If no match is found, and the type sought is a vector type, then the |
| 868 | largest vector type that is smaller than the sought vector type will be used |
| 869 | as a fall back. This happens because <128 x double> can be implemented in |
| 870 | terms of 64 <2 x double>, for example.</li> |
| 871 | </ol> |
| 872 | </div> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 873 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 874 | <!-- *********************************************************************** --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 875 | <div class="doc_section"> <a name="typesystem">Type System</a> </div> |
| 876 | <!-- *********************************************************************** --> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 877 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 878 | <div class="doc_text"> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 879 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 880 | <p>The LLVM type system is one of the most important features of the |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 881 | intermediate representation. Being typed enables a number of |
| 882 | optimizations to be performed on the IR directly, without having to do |
| 883 | extra analyses on the side before the transformation. A strong type |
| 884 | system makes it easier to read the generated code and enables novel |
| 885 | analyses and transformations that are not feasible to perform on normal |
| 886 | three address code representations.</p> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 887 | |
| 888 | </div> |
| 889 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 890 | <!-- ======================================================================= --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 891 | <div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 892 | <div class="doc_text"> |
John Criswell | 4457dc9 | 2004-04-09 16:48:45 +0000 | [diff] [blame] | 893 | <p>The primitive types are the fundamental building blocks of the LLVM |
Chris Lattner | d4f6b17 | 2005-03-07 22:13:59 +0000 | [diff] [blame] | 894 | system. The current set of primitive types is as follows:</p> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 895 | |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 896 | <table class="layout"> |
| 897 | <tr class="layout"> |
| 898 | <td class="left"> |
| 899 | <table> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 900 | <tbody> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 901 | <tr><th>Type</th><th>Description</th></tr> |
Duncan Sands | 8036ca4 | 2007-03-30 12:22:09 +0000 | [diff] [blame] | 902 | <tr><td><tt><a name="t_void">void</a></tt></td><td>No value</td></tr> |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 903 | <tr><td><tt>i8</tt></td><td>8-bit value</td></tr> |
| 904 | <tr><td><tt>i32</tt></td><td>32-bit value</td></tr> |
Misha Brukman | cfa87bc | 2005-04-22 18:02:52 +0000 | [diff] [blame] | 905 | <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 906 | <tr><td><tt>label</tt></td><td>Branch destination</td></tr> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 907 | </tbody> |
| 908 | </table> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 909 | </td> |
| 910 | <td class="right"> |
| 911 | <table> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 912 | <tbody> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 913 | <tr><th>Type</th><th>Description</th></tr> |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 914 | <tr><td><tt>i1</tt></td><td>True or False value</td></tr> |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 915 | <tr><td><tt>i16</tt></td><td>16-bit value</td></tr> |
| 916 | <tr><td><tt>i64</tt></td><td>64-bit value</td></tr> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 917 | <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 918 | </tbody> |
| 919 | </table> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 920 | </td> |
| 921 | </tr> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 922 | </table> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 923 | </div> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 924 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 925 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 926 | <div class="doc_subsubsection"> <a name="t_classifications">Type |
| 927 | Classifications</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 928 | <div class="doc_text"> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 929 | <p>These different primitive types fall into a few useful |
| 930 | classifications:</p> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 931 | |
| 932 | <table border="1" cellspacing="0" cellpadding="4"> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 933 | <tbody> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 934 | <tr><th>Classification</th><th>Types</th></tr> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 935 | <tr> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 936 | <td><a name="t_integer">integer</a></td> |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 937 | <td><tt>i1, i8, i16, i32, i64</tt></td> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 938 | </tr> |
| 939 | <tr> |
| 940 | <td><a name="t_floating">floating point</a></td> |
| 941 | <td><tt>float, double</tt></td> |
| 942 | </tr> |
| 943 | <tr> |
| 944 | <td><a name="t_firstclass">first class</a></td> |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 945 | <td><tt>i1, i8, i16, i32, i64, float, double, <br/> |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 946 | <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 947 | </td> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 948 | </tr> |
| 949 | </tbody> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 950 | </table> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 951 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 952 | <p>The <a href="#t_firstclass">first class</a> types are perhaps the |
| 953 | most important. Values of these types are the only ones which can be |
| 954 | produced by instructions, passed as arguments, or used as operands to |
| 955 | instructions. This means that all structures and arrays must be |
| 956 | manipulated either by pointer or by component.</p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 957 | </div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 958 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 959 | <!-- ======================================================================= --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 960 | <div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 961 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 962 | <div class="doc_text"> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 963 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 964 | <p>The real power in LLVM comes from the derived types in the system. |
| 965 | This is what allows a programmer to represent arrays, functions, |
| 966 | pointers, and other useful types. Note that these derived types may be |
| 967 | recursive: For example, it is possible to have a two dimensional array.</p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 968 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 969 | </div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 970 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 971 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 972 | <div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 973 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 974 | <div class="doc_text"> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 975 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 976 | <h5>Overview:</h5> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 977 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 978 | <p>The array type is a very simple derived type that arranges elements |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 979 | sequentially in memory. The array type requires a size (number of |
| 980 | elements) and an underlying data type.</p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 981 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 982 | <h5>Syntax:</h5> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 983 | |
| 984 | <pre> |
| 985 | [<# elements> x <elementtype>] |
| 986 | </pre> |
| 987 | |
John Criswell | e4c57cc | 2005-05-12 16:52:32 +0000 | [diff] [blame] | 988 | <p>The number of elements is a constant integer value; elementtype may |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 989 | be any type with a size.</p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 990 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 991 | <h5>Examples:</h5> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 992 | <table class="layout"> |
| 993 | <tr class="layout"> |
| 994 | <td class="left"> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 995 | <tt>[40 x i32 ]</tt><br/> |
| 996 | <tt>[41 x i32 ]</tt><br/> |
Reid Spencer | a517338 | 2007-01-04 16:43:23 +0000 | [diff] [blame] | 997 | <tt>[40 x i8]</tt><br/> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 998 | </td> |
| 999 | <td class="left"> |
Reid Spencer | a517338 | 2007-01-04 16:43:23 +0000 | [diff] [blame] | 1000 | Array of 40 32-bit integer values.<br/> |
| 1001 | Array of 41 32-bit integer values.<br/> |
| 1002 | Array of 40 8-bit integer values.<br/> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1003 | </td> |
| 1004 | </tr> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1005 | </table> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1006 | <p>Here are some examples of multidimensional arrays:</p> |
| 1007 | <table class="layout"> |
| 1008 | <tr class="layout"> |
| 1009 | <td class="left"> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1010 | <tt>[3 x [4 x i32]]</tt><br/> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1011 | <tt>[12 x [10 x float]]</tt><br/> |
Reid Spencer | a517338 | 2007-01-04 16:43:23 +0000 | [diff] [blame] | 1012 | <tt>[2 x [3 x [4 x i16]]]</tt><br/> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1013 | </td> |
| 1014 | <td class="left"> |
Reid Spencer | a517338 | 2007-01-04 16:43:23 +0000 | [diff] [blame] | 1015 | 3x4 array of 32-bit integer values.<br/> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1016 | 12x10 array of single precision floating point values.<br/> |
Reid Spencer | a517338 | 2007-01-04 16:43:23 +0000 | [diff] [blame] | 1017 | 2x3x4 array of 16-bit integer values.<br/> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1018 | </td> |
| 1019 | </tr> |
| 1020 | </table> |
Chris Lattner | e67a951 | 2005-06-24 17:22:57 +0000 | [diff] [blame] | 1021 | |
John Criswell | 0ec250c | 2005-10-24 16:17:18 +0000 | [diff] [blame] | 1022 | <p>Note that 'variable sized arrays' can be implemented in LLVM with a zero |
| 1023 | length array. Normally, accesses past the end of an array are undefined in |
Chris Lattner | e67a951 | 2005-06-24 17:22:57 +0000 | [diff] [blame] | 1024 | LLVM (e.g. it is illegal to access the 5th element of a 3 element array). |
| 1025 | As a special case, however, zero length arrays are recognized to be variable |
| 1026 | length. This allows implementation of 'pascal style arrays' with the LLVM |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1027 | type "{ i32, [0 x float]}", for example.</p> |
Chris Lattner | e67a951 | 2005-06-24 17:22:57 +0000 | [diff] [blame] | 1028 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1029 | </div> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1030 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1031 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1032 | <div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1033 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1034 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1035 | <p>The function type can be thought of as a function signature. It |
| 1036 | consists of a return type and a list of formal parameter types. |
John Criswell | 009900b | 2003-11-25 21:45:46 +0000 | [diff] [blame] | 1037 | Function types are usually used to build virtual function tables |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1038 | (which are structures of pointers to functions), for indirect function |
| 1039 | calls, and when defining a function.</p> |
John Criswell | 009900b | 2003-11-25 21:45:46 +0000 | [diff] [blame] | 1040 | <p> |
| 1041 | The return type of a function type cannot be an aggregate type. |
| 1042 | </p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1043 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1044 | <pre> <returntype> (<parameter list>)<br></pre> |
John Criswell | 0ec250c | 2005-10-24 16:17:18 +0000 | [diff] [blame] | 1045 | <p>...where '<tt><parameter list></tt>' is a comma-separated list of type |
Misha Brukman | c24b758 | 2004-08-12 20:16:08 +0000 | [diff] [blame] | 1046 | specifiers. Optionally, the parameter list may include a type <tt>...</tt>, |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1047 | which indicates that the function takes a variable number of arguments. |
| 1048 | Variable argument functions can access their arguments with the <a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1049 | href="#int_varargs">variable argument handling intrinsic</a> functions.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1050 | <h5>Examples:</h5> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1051 | <table class="layout"> |
| 1052 | <tr class="layout"> |
Reid Spencer | 92f8230 | 2006-12-31 07:18:34 +0000 | [diff] [blame] | 1053 | <td class="left"><tt>i32 (i32)</tt></td> |
| 1054 | <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1055 | </td> |
Reid Spencer | 92f8230 | 2006-12-31 07:18:34 +0000 | [diff] [blame] | 1056 | </tr><tr class="layout"> |
Reid Spencer | 7bf214d | 2007-01-15 18:28:34 +0000 | [diff] [blame] | 1057 | <td class="left"><tt>float (i16 sext, i32 *) * |
Reid Spencer | f17a0b7 | 2006-12-31 07:20:23 +0000 | [diff] [blame] | 1058 | </tt></td> |
Reid Spencer | 92f8230 | 2006-12-31 07:18:34 +0000 | [diff] [blame] | 1059 | <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes |
| 1060 | an <tt>i16</tt> that should be sign extended and a |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1061 | <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning |
Reid Spencer | 92f8230 | 2006-12-31 07:18:34 +0000 | [diff] [blame] | 1062 | <tt>float</tt>. |
| 1063 | </td> |
| 1064 | </tr><tr class="layout"> |
| 1065 | <td class="left"><tt>i32 (i8*, ...)</tt></td> |
| 1066 | <td class="left">A vararg function that takes at least one |
Reid Spencer | a517338 | 2007-01-04 16:43:23 +0000 | [diff] [blame] | 1067 | <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C), |
Reid Spencer | 92f8230 | 2006-12-31 07:18:34 +0000 | [diff] [blame] | 1068 | which returns an integer. This is the signature for <tt>printf</tt> in |
| 1069 | LLVM. |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1070 | </td> |
| 1071 | </tr> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1072 | </table> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 1073 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1074 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1075 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1076 | <div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1077 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1078 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1079 | <p>The structure type is used to represent a collection of data members |
| 1080 | together in memory. The packing of the field types is defined to match |
| 1081 | the ABI of the underlying processor. The elements of a structure may |
| 1082 | be any type that has a size.</p> |
| 1083 | <p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> |
| 1084 | and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a |
| 1085 | field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' |
| 1086 | instruction.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1087 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1088 | <pre> { <type list> }<br></pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1089 | <h5>Examples:</h5> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1090 | <table class="layout"> |
| 1091 | <tr class="layout"> |
Jeff Cohen | 6f1cc77 | 2007-04-22 01:17:39 +0000 | [diff] [blame] | 1092 | <td class="left"><tt>{ i32, i32, i32 }</tt></td> |
| 1093 | <td class="left">A triple of three <tt>i32</tt> values</td> |
| 1094 | </tr><tr class="layout"> |
| 1095 | <td class="left"><tt>{ float, i32 (i32) * }</tt></td> |
| 1096 | <td class="left">A pair, where the first element is a <tt>float</tt> and the |
| 1097 | second element is a <a href="#t_pointer">pointer</a> to a |
| 1098 | <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning |
| 1099 | an <tt>i32</tt>.</td> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1100 | </tr> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1101 | </table> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1102 | </div> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1103 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1104 | <!-- _______________________________________________________________________ --> |
Andrew Lenharth | 75e1068 | 2006-12-08 17:13:00 +0000 | [diff] [blame] | 1105 | <div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a> |
| 1106 | </div> |
| 1107 | <div class="doc_text"> |
| 1108 | <h5>Overview:</h5> |
| 1109 | <p>The packed structure type is used to represent a collection of data members |
| 1110 | together in memory. There is no padding between fields. Further, the alignment |
| 1111 | of a packed structure is 1 byte. The elements of a packed structure may |
| 1112 | be any type that has a size.</p> |
| 1113 | <p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> |
| 1114 | and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a |
| 1115 | field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' |
| 1116 | instruction.</p> |
| 1117 | <h5>Syntax:</h5> |
| 1118 | <pre> < { <type list> } > <br></pre> |
| 1119 | <h5>Examples:</h5> |
| 1120 | <table class="layout"> |
| 1121 | <tr class="layout"> |
Jeff Cohen | 6f1cc77 | 2007-04-22 01:17:39 +0000 | [diff] [blame] | 1122 | <td class="left"><tt>< { i32, i32, i32 } ></tt></td> |
| 1123 | <td class="left">A triple of three <tt>i32</tt> values</td> |
| 1124 | </tr><tr class="layout"> |
| 1125 | <td class="left"><tt>< { float, i32 (i32) * } ></tt></td> |
| 1126 | <td class="left">A pair, where the first element is a <tt>float</tt> and the |
| 1127 | second element is a <a href="#t_pointer">pointer</a> to a |
| 1128 | <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning |
| 1129 | an <tt>i32</tt>.</td> |
Andrew Lenharth | 75e1068 | 2006-12-08 17:13:00 +0000 | [diff] [blame] | 1130 | </tr> |
| 1131 | </table> |
| 1132 | </div> |
| 1133 | |
| 1134 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1135 | <div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1136 | <div class="doc_text"> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1137 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1138 | <p>As in many languages, the pointer type represents a pointer or |
| 1139 | reference to another object, which must live in memory.</p> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1140 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1141 | <pre> <type> *<br></pre> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1142 | <h5>Examples:</h5> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1143 | <table class="layout"> |
| 1144 | <tr class="layout"> |
| 1145 | <td class="left"> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1146 | <tt>[4x i32]*</tt><br/> |
| 1147 | <tt>i32 (i32 *) *</tt><br/> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1148 | </td> |
| 1149 | <td class="left"> |
| 1150 | A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1151 | four <tt>i32</tt> values<br/> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1152 | A <a href="#t_pointer">pointer</a> to a <a |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1153 | href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an |
| 1154 | <tt>i32</tt>.<br/> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1155 | </td> |
| 1156 | </tr> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1157 | </table> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1158 | </div> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1159 | |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1160 | <!-- _______________________________________________________________________ --> |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 1161 | <div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1162 | <div class="doc_text"> |
Chris Lattner | 69c11bb | 2005-04-25 17:34:15 +0000 | [diff] [blame] | 1163 | |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1164 | <h5>Overview:</h5> |
Chris Lattner | 69c11bb | 2005-04-25 17:34:15 +0000 | [diff] [blame] | 1165 | |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 1166 | <p>A vector type is a simple derived type that represents a vector |
| 1167 | of elements. Vector types are used when multiple primitive data |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1168 | are operated in parallel using a single instruction (SIMD). |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 1169 | A vector type requires a size (number of |
Chris Lattner | b8d172f | 2005-11-10 01:44:22 +0000 | [diff] [blame] | 1170 | elements) and an underlying primitive data type. Vectors must have a power |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 1171 | of two length (1, 2, 4, 8, 16 ...). Vector types are |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1172 | considered <a href="#t_firstclass">first class</a>.</p> |
Chris Lattner | 69c11bb | 2005-04-25 17:34:15 +0000 | [diff] [blame] | 1173 | |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1174 | <h5>Syntax:</h5> |
Chris Lattner | 69c11bb | 2005-04-25 17:34:15 +0000 | [diff] [blame] | 1175 | |
| 1176 | <pre> |
| 1177 | < <# elements> x <elementtype> > |
| 1178 | </pre> |
| 1179 | |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 1180 | <p>The number of elements is a constant integer value; elementtype may |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 1181 | be any integer or floating point type.</p> |
Chris Lattner | 69c11bb | 2005-04-25 17:34:15 +0000 | [diff] [blame] | 1182 | |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1183 | <h5>Examples:</h5> |
Chris Lattner | 69c11bb | 2005-04-25 17:34:15 +0000 | [diff] [blame] | 1184 | |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1185 | <table class="layout"> |
| 1186 | <tr class="layout"> |
| 1187 | <td class="left"> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1188 | <tt><4 x i32></tt><br/> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1189 | <tt><8 x float></tt><br/> |
Reid Spencer | a517338 | 2007-01-04 16:43:23 +0000 | [diff] [blame] | 1190 | <tt><2 x i64></tt><br/> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1191 | </td> |
| 1192 | <td class="left"> |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 1193 | Vector of 4 32-bit integer values.<br/> |
| 1194 | Vector of 8 floating-point values.<br/> |
| 1195 | Vector of 2 64-bit integer values.<br/> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1196 | </td> |
| 1197 | </tr> |
| 1198 | </table> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1199 | </div> |
| 1200 | |
Chris Lattner | 69c11bb | 2005-04-25 17:34:15 +0000 | [diff] [blame] | 1201 | <!-- _______________________________________________________________________ --> |
| 1202 | <div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div> |
| 1203 | <div class="doc_text"> |
| 1204 | |
| 1205 | <h5>Overview:</h5> |
| 1206 | |
| 1207 | <p>Opaque types are used to represent unknown types in the system. This |
| 1208 | corresponds (for example) to the C notion of a foward declared structure type. |
| 1209 | In LLVM, opaque types can eventually be resolved to any type (not just a |
| 1210 | structure type).</p> |
| 1211 | |
| 1212 | <h5>Syntax:</h5> |
| 1213 | |
| 1214 | <pre> |
| 1215 | opaque |
| 1216 | </pre> |
| 1217 | |
| 1218 | <h5>Examples:</h5> |
| 1219 | |
| 1220 | <table class="layout"> |
| 1221 | <tr class="layout"> |
| 1222 | <td class="left"> |
| 1223 | <tt>opaque</tt> |
| 1224 | </td> |
| 1225 | <td class="left"> |
| 1226 | An opaque type.<br/> |
| 1227 | </td> |
| 1228 | </tr> |
| 1229 | </table> |
| 1230 | </div> |
| 1231 | |
| 1232 | |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1233 | <!-- *********************************************************************** --> |
| 1234 | <div class="doc_section"> <a name="constants">Constants</a> </div> |
| 1235 | <!-- *********************************************************************** --> |
| 1236 | |
| 1237 | <div class="doc_text"> |
| 1238 | |
| 1239 | <p>LLVM has several different basic types of constants. This section describes |
| 1240 | them all and their syntax.</p> |
| 1241 | |
| 1242 | </div> |
| 1243 | |
| 1244 | <!-- ======================================================================= --> |
Reid Spencer | cc16dc3 | 2004-12-09 18:02:53 +0000 | [diff] [blame] | 1245 | <div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1246 | |
| 1247 | <div class="doc_text"> |
| 1248 | |
| 1249 | <dl> |
| 1250 | <dt><b>Boolean constants</b></dt> |
| 1251 | |
| 1252 | <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 1253 | constants of the <tt><a href="#t_primitive">i1</a></tt> type. |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1254 | </dd> |
| 1255 | |
| 1256 | <dt><b>Integer constants</b></dt> |
| 1257 | |
Reid Spencer | cc16dc3 | 2004-12-09 18:02:53 +0000 | [diff] [blame] | 1258 | <dd>Standard integers (such as '4') are constants of the <a |
Reid Spencer | a517338 | 2007-01-04 16:43:23 +0000 | [diff] [blame] | 1259 | href="#t_integer">integer</a> type. Negative numbers may be used with |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1260 | integer types. |
| 1261 | </dd> |
| 1262 | |
| 1263 | <dt><b>Floating point constants</b></dt> |
| 1264 | |
| 1265 | <dd>Floating point constants use standard decimal notation (e.g. 123.421), |
| 1266 | exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1267 | notation (see below). Floating point constants must have a <a |
| 1268 | href="#t_floating">floating point</a> type. </dd> |
| 1269 | |
| 1270 | <dt><b>Null pointer constants</b></dt> |
| 1271 | |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 1272 | <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1273 | and must be of <a href="#t_pointer">pointer type</a>.</dd> |
| 1274 | |
| 1275 | </dl> |
| 1276 | |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 1277 | <p>The one non-intuitive notation for constants is the optional hexadecimal form |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1278 | of floating point constants. For example, the form '<tt>double |
| 1279 | 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double |
| 1280 | 4.5e+15</tt>'. The only time hexadecimal floating point constants are required |
Reid Spencer | cc16dc3 | 2004-12-09 18:02:53 +0000 | [diff] [blame] | 1281 | (and the only time that they are generated by the disassembler) is when a |
| 1282 | floating point constant must be emitted but it cannot be represented as a |
| 1283 | decimal floating point number. For example, NaN's, infinities, and other |
| 1284 | special values are represented in their IEEE hexadecimal format so that |
| 1285 | assembly and disassembly do not cause any bits to change in the constants.</p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1286 | |
| 1287 | </div> |
| 1288 | |
| 1289 | <!-- ======================================================================= --> |
| 1290 | <div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a> |
| 1291 | </div> |
| 1292 | |
| 1293 | <div class="doc_text"> |
Chris Lattner | d4f6b17 | 2005-03-07 22:13:59 +0000 | [diff] [blame] | 1294 | <p>Aggregate constants arise from aggregation of simple constants |
| 1295 | and smaller aggregate constants.</p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1296 | |
| 1297 | <dl> |
| 1298 | <dt><b>Structure constants</b></dt> |
| 1299 | |
| 1300 | <dd>Structure constants are represented with notation similar to structure |
| 1301 | type definitions (a comma separated list of elements, surrounded by braces |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1302 | (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>", |
| 1303 | where "<tt>%G</tt>" is declared as "<tt>%G = external global i32</tt>". Structure constants |
Chris Lattner | d4f6b17 | 2005-03-07 22:13:59 +0000 | [diff] [blame] | 1304 | must have <a href="#t_struct">structure type</a>, and the number and |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1305 | types of elements must match those specified by the type. |
| 1306 | </dd> |
| 1307 | |
| 1308 | <dt><b>Array constants</b></dt> |
| 1309 | |
| 1310 | <dd>Array constants are represented with notation similar to array type |
| 1311 | definitions (a comma separated list of elements, surrounded by square brackets |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1312 | (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1313 | constants must have <a href="#t_array">array type</a>, and the number and |
| 1314 | types of elements must match those specified by the type. |
| 1315 | </dd> |
| 1316 | |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 1317 | <dt><b>Vector constants</b></dt> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1318 | |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 1319 | <dd>Vector constants are represented with notation similar to vector type |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1320 | definitions (a comma separated list of elements, surrounded by |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1321 | less-than/greater-than's (<tt><></tt>)). For example: "<tt>< i32 42, |
Jeff Cohen | 6f1cc77 | 2007-04-22 01:17:39 +0000 | [diff] [blame] | 1322 | i32 11, i32 74, i32 100 ></tt>". Vector constants must have <a |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 1323 | href="#t_vector">vector type</a>, and the number and types of elements must |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1324 | match those specified by the type. |
| 1325 | </dd> |
| 1326 | |
| 1327 | <dt><b>Zero initialization</b></dt> |
| 1328 | |
| 1329 | <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a |
| 1330 | value to zero of <em>any</em> type, including scalar and aggregate types. |
| 1331 | This is often used to avoid having to print large zero initializers (e.g. for |
John Criswell | 0ec250c | 2005-10-24 16:17:18 +0000 | [diff] [blame] | 1332 | large arrays) and is always exactly equivalent to using explicit zero |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1333 | initializers. |
| 1334 | </dd> |
| 1335 | </dl> |
| 1336 | |
| 1337 | </div> |
| 1338 | |
| 1339 | <!-- ======================================================================= --> |
| 1340 | <div class="doc_subsection"> |
| 1341 | <a name="globalconstants">Global Variable and Function Addresses</a> |
| 1342 | </div> |
| 1343 | |
| 1344 | <div class="doc_text"> |
| 1345 | |
| 1346 | <p>The addresses of <a href="#globalvars">global variables</a> and <a |
| 1347 | href="#functionstructure">functions</a> are always implicitly valid (link-time) |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 1348 | constants. These constants are explicitly referenced when the <a |
| 1349 | href="#identifiers">identifier for the global</a> is used and always have <a |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1350 | href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM |
| 1351 | file:</p> |
| 1352 | |
| 1353 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1354 | %X = global i32 17 |
| 1355 | %Y = global i32 42 |
| 1356 | %Z = global [2 x i32*] [ i32* %X, i32* %Y ] |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1357 | </pre> |
| 1358 | |
| 1359 | </div> |
| 1360 | |
| 1361 | <!-- ======================================================================= --> |
Reid Spencer | 2dc45b8 | 2004-12-09 18:13:12 +0000 | [diff] [blame] | 1362 | <div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1363 | <div class="doc_text"> |
Reid Spencer | 2dc45b8 | 2004-12-09 18:13:12 +0000 | [diff] [blame] | 1364 | <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 1365 | no specific value. Undefined values may be of any type and be used anywhere |
Reid Spencer | 2dc45b8 | 2004-12-09 18:13:12 +0000 | [diff] [blame] | 1366 | a constant is permitted.</p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1367 | |
Reid Spencer | 2dc45b8 | 2004-12-09 18:13:12 +0000 | [diff] [blame] | 1368 | <p>Undefined values indicate to the compiler that the program is well defined |
| 1369 | no matter what value is used, giving the compiler more freedom to optimize. |
| 1370 | </p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1371 | </div> |
| 1372 | |
| 1373 | <!-- ======================================================================= --> |
| 1374 | <div class="doc_subsection"><a name="constantexprs">Constant Expressions</a> |
| 1375 | </div> |
| 1376 | |
| 1377 | <div class="doc_text"> |
| 1378 | |
| 1379 | <p>Constant expressions are used to allow expressions involving other constants |
| 1380 | to be used as constants. Constant expressions may be of any <a |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 1381 | href="#t_firstclass">first class</a> type and may involve any LLVM operation |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1382 | that does not have side effects (e.g. load and call are not supported). The |
| 1383 | following is the syntax for constant expressions:</p> |
| 1384 | |
| 1385 | <dl> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1386 | <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt> |
| 1387 | <dd>Truncate a constant to another type. The bit size of CST must be larger |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 1388 | than the bit size of TYPE. Both types must be integers.</dd> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1389 | |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1390 | <dt><b><tt>zext ( CST to TYPE )</tt></b></dt> |
| 1391 | <dd>Zero extend a constant to another type. The bit size of CST must be |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 1392 | smaller or equal to the bit size of TYPE. Both types must be integers.</dd> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1393 | |
| 1394 | <dt><b><tt>sext ( CST to TYPE )</tt></b></dt> |
| 1395 | <dd>Sign extend a constant to another type. The bit size of CST must be |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 1396 | smaller or equal to the bit size of TYPE. Both types must be integers.</dd> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1397 | |
| 1398 | <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt> |
| 1399 | <dd>Truncate a floating point constant to another floating point type. The |
| 1400 | size of CST must be larger than the size of TYPE. Both types must be |
| 1401 | floating point.</dd> |
| 1402 | |
| 1403 | <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt> |
| 1404 | <dd>Floating point extend a constant to another type. The size of CST must be |
| 1405 | smaller or equal to the size of TYPE. Both types must be floating point.</dd> |
| 1406 | |
| 1407 | <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt> |
| 1408 | <dd>Convert a floating point constant to the corresponding unsigned integer |
| 1409 | constant. TYPE must be an integer type. CST must be floating point. If the |
| 1410 | value won't fit in the integer type, the results are undefined.</dd> |
| 1411 | |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 1412 | <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1413 | <dd>Convert a floating point constant to the corresponding signed integer |
| 1414 | constant. TYPE must be an integer type. CST must be floating point. If the |
| 1415 | value won't fit in the integer type, the results are undefined.</dd> |
| 1416 | |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 1417 | <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1418 | <dd>Convert an unsigned integer constant to the corresponding floating point |
| 1419 | constant. TYPE must be floating point. CST must be of integer type. If the |
Jeff Cohen | cb75731 | 2007-04-22 14:56:37 +0000 | [diff] [blame] | 1420 | value won't fit in the floating point type, the results are undefined.</dd> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1421 | |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 1422 | <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1423 | <dd>Convert a signed integer constant to the corresponding floating point |
| 1424 | constant. TYPE must be floating point. CST must be of integer type. If the |
Jeff Cohen | cb75731 | 2007-04-22 14:56:37 +0000 | [diff] [blame] | 1425 | value won't fit in the floating point type, the results are undefined.</dd> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1426 | |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 1427 | <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt> |
| 1428 | <dd>Convert a pointer typed constant to the corresponding integer constant |
| 1429 | TYPE must be an integer type. CST must be of pointer type. The CST value is |
| 1430 | zero extended, truncated, or unchanged to make it fit in TYPE.</dd> |
| 1431 | |
| 1432 | <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt> |
| 1433 | <dd>Convert a integer constant to a pointer constant. TYPE must be a |
| 1434 | pointer type. CST must be of integer type. The CST value is zero extended, |
| 1435 | truncated, or unchanged to make it fit in a pointer size. This one is |
| 1436 | <i>really</i> dangerous!</dd> |
| 1437 | |
| 1438 | <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1439 | <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be |
| 1440 | identical (same number of bits). The conversion is done as if the CST value |
| 1441 | was stored to memory and read back as TYPE. In other words, no bits change |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 1442 | with this operator, just the type. This can be used for conversion of |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 1443 | vector types to any other type, as long as they have the same bit width. For |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 1444 | pointers it is only valid to cast to another pointer type. |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1445 | </dd> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1446 | |
| 1447 | <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt> |
| 1448 | |
| 1449 | <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on |
| 1450 | constants. As with the <a href="#i_getelementptr">getelementptr</a> |
| 1451 | instruction, the index list may have zero or more indexes, which are required |
| 1452 | to make sense for the type of "CSTPTR".</dd> |
| 1453 | |
Robert Bocchino | 9fbe145 | 2006-01-10 19:31:34 +0000 | [diff] [blame] | 1454 | <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt> |
| 1455 | |
| 1456 | <dd>Perform the <a href="#i_select">select operation</a> on |
Reid Spencer | 01c4259 | 2006-12-04 19:23:19 +0000 | [diff] [blame] | 1457 | constants.</dd> |
| 1458 | |
| 1459 | <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt> |
| 1460 | <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd> |
| 1461 | |
| 1462 | <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt> |
| 1463 | <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd> |
Robert Bocchino | 9fbe145 | 2006-01-10 19:31:34 +0000 | [diff] [blame] | 1464 | |
| 1465 | <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt> |
| 1466 | |
| 1467 | <dd>Perform the <a href="#i_extractelement">extractelement |
| 1468 | operation</a> on constants. |
| 1469 | |
Robert Bocchino | 05ccd70 | 2006-01-15 20:48:27 +0000 | [diff] [blame] | 1470 | <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt> |
| 1471 | |
| 1472 | <dd>Perform the <a href="#i_insertelement">insertelement |
Reid Spencer | 01c4259 | 2006-12-04 19:23:19 +0000 | [diff] [blame] | 1473 | operation</a> on constants.</dd> |
Robert Bocchino | 05ccd70 | 2006-01-15 20:48:27 +0000 | [diff] [blame] | 1474 | |
Chris Lattner | c198954 | 2006-04-08 00:13:41 +0000 | [diff] [blame] | 1475 | |
| 1476 | <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt> |
| 1477 | |
| 1478 | <dd>Perform the <a href="#i_shufflevector">shufflevector |
Reid Spencer | 01c4259 | 2006-12-04 19:23:19 +0000 | [diff] [blame] | 1479 | operation</a> on constants.</dd> |
Chris Lattner | c198954 | 2006-04-08 00:13:41 +0000 | [diff] [blame] | 1480 | |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1481 | <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt> |
| 1482 | |
Reid Spencer | 2dc45b8 | 2004-12-09 18:13:12 +0000 | [diff] [blame] | 1483 | <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may |
| 1484 | be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1485 | binary</a> operations. The constraints on operands are the same as those for |
| 1486 | the corresponding instruction (e.g. no bitwise operations on floating point |
John Criswell | e4c57cc | 2005-05-12 16:52:32 +0000 | [diff] [blame] | 1487 | values are allowed).</dd> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1488 | </dl> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1489 | </div> |
Chris Lattner | 9ee5d22 | 2004-03-08 16:49:10 +0000 | [diff] [blame] | 1490 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1491 | <!-- *********************************************************************** --> |
Chris Lattner | e87d653 | 2006-01-25 23:47:57 +0000 | [diff] [blame] | 1492 | <div class="doc_section"> <a name="othervalues">Other Values</a> </div> |
| 1493 | <!-- *********************************************************************** --> |
| 1494 | |
| 1495 | <!-- ======================================================================= --> |
| 1496 | <div class="doc_subsection"> |
| 1497 | <a name="inlineasm">Inline Assembler Expressions</a> |
| 1498 | </div> |
| 1499 | |
| 1500 | <div class="doc_text"> |
| 1501 | |
| 1502 | <p> |
| 1503 | LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm"> |
| 1504 | Module-Level Inline Assembly</a>) through the use of a special value. This |
| 1505 | value represents the inline assembler as a string (containing the instructions |
| 1506 | to emit), a list of operand constraints (stored as a string), and a flag that |
| 1507 | indicates whether or not the inline asm expression has side effects. An example |
| 1508 | inline assembler expression is: |
| 1509 | </p> |
| 1510 | |
| 1511 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1512 | i32 (i32) asm "bswap $0", "=r,r" |
Chris Lattner | e87d653 | 2006-01-25 23:47:57 +0000 | [diff] [blame] | 1513 | </pre> |
| 1514 | |
| 1515 | <p> |
| 1516 | Inline assembler expressions may <b>only</b> be used as the callee operand of |
| 1517 | a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have: |
| 1518 | </p> |
| 1519 | |
| 1520 | <pre> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 1521 | %X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y) |
Chris Lattner | e87d653 | 2006-01-25 23:47:57 +0000 | [diff] [blame] | 1522 | </pre> |
| 1523 | |
| 1524 | <p> |
| 1525 | Inline asms with side effects not visible in the constraint list must be marked |
| 1526 | as having side effects. This is done through the use of the |
| 1527 | '<tt>sideeffect</tt>' keyword, like so: |
| 1528 | </p> |
| 1529 | |
| 1530 | <pre> |
| 1531 | call void asm sideeffect "eieio", ""() |
| 1532 | </pre> |
| 1533 | |
| 1534 | <p>TODO: The format of the asm and constraints string still need to be |
| 1535 | documented here. Constraints on what can be done (e.g. duplication, moving, etc |
| 1536 | need to be documented). |
| 1537 | </p> |
| 1538 | |
| 1539 | </div> |
| 1540 | |
| 1541 | <!-- *********************************************************************** --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1542 | <div class="doc_section"> <a name="instref">Instruction Reference</a> </div> |
| 1543 | <!-- *********************************************************************** --> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1544 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1545 | <div class="doc_text"> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1546 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1547 | <p>The LLVM instruction set consists of several different |
| 1548 | classifications of instructions: <a href="#terminators">terminator |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 1549 | instructions</a>, <a href="#binaryops">binary instructions</a>, |
| 1550 | <a href="#bitwiseops">bitwise binary instructions</a>, <a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1551 | href="#memoryops">memory instructions</a>, and <a href="#otherops">other |
| 1552 | instructions</a>.</p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1553 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1554 | </div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1555 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1556 | <!-- ======================================================================= --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1557 | <div class="doc_subsection"> <a name="terminators">Terminator |
| 1558 | Instructions</a> </div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1559 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1560 | <div class="doc_text"> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1561 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1562 | <p>As mentioned <a href="#functionstructure">previously</a>, every |
| 1563 | basic block in a program ends with a "Terminator" instruction, which |
| 1564 | indicates which block should be executed after the current block is |
| 1565 | finished. These terminator instructions typically yield a '<tt>void</tt>' |
| 1566 | value: they produce control flow, not values (the one exception being |
| 1567 | the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p> |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 1568 | <p>There are six different terminator instructions: the '<a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1569 | href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>' |
| 1570 | instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction, |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1571 | the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a |
| 1572 | href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a |
| 1573 | href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1574 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1575 | </div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1576 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1577 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1578 | <div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>' |
| 1579 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1580 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1581 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1582 | <pre> ret <type> <value> <i>; Return a value from a non-void function</i> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1583 | ret void <i>; Return from void function</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1584 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1585 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1586 | <p>The '<tt>ret</tt>' instruction is used to return control flow (and a |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 1587 | value) from a function back to the caller.</p> |
John Criswell | 4457dc9 | 2004-04-09 16:48:45 +0000 | [diff] [blame] | 1588 | <p>There are two forms of the '<tt>ret</tt>' instruction: one that |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1589 | returns a value and then causes control flow, and one that just causes |
| 1590 | control flow to occur.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1591 | <h5>Arguments:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1592 | <p>The '<tt>ret</tt>' instruction may return any '<a |
| 1593 | href="#t_firstclass">first class</a>' type. Notice that a function is |
| 1594 | not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>' |
| 1595 | instruction inside of the function that returns a value that does not |
| 1596 | match the return type of the function.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1597 | <h5>Semantics:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1598 | <p>When the '<tt>ret</tt>' instruction is executed, control flow |
| 1599 | returns back to the calling function's context. If the caller is a "<a |
John Criswell | fa08187 | 2004-06-25 15:16:57 +0000 | [diff] [blame] | 1600 | href="#i_call"><tt>call</tt></a>" instruction, execution continues at |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1601 | the instruction after the call. If the caller was an "<a |
| 1602 | href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues |
John Criswell | e4c57cc | 2005-05-12 16:52:32 +0000 | [diff] [blame] | 1603 | at the beginning of the "normal" destination block. If the instruction |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1604 | returns a value, that value shall set the call or invoke instruction's |
| 1605 | return value.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1606 | <h5>Example:</h5> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1607 | <pre> ret i32 5 <i>; Return an integer value of 5</i> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1608 | ret void <i>; Return from a void function</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1609 | </pre> |
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 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1612 | <div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1613 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1614 | <h5>Syntax:</h5> |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 1615 | <pre> br i1 <cond>, label <iftrue>, label <iffalse><br> br label <dest> <i>; Unconditional branch</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1616 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1617 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1618 | <p>The '<tt>br</tt>' instruction is used to cause control flow to |
| 1619 | transfer to a different basic block in the current function. There are |
| 1620 | two forms of this instruction, corresponding to a conditional branch |
| 1621 | and an unconditional branch.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1622 | <h5>Arguments:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1623 | <p>The conditional branch form of the '<tt>br</tt>' instruction takes a |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 1624 | single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The |
Reid Spencer | de15194 | 2007-02-19 23:54:10 +0000 | [diff] [blame] | 1625 | unconditional form of the '<tt>br</tt>' instruction takes a single |
| 1626 | '<tt>label</tt>' value as a target.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1627 | <h5>Semantics:</h5> |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 1628 | <p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>' |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1629 | argument is evaluated. If the value is <tt>true</tt>, control flows |
| 1630 | to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>, |
| 1631 | control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1632 | <h5>Example:</h5> |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 1633 | <pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1634 | href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1635 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1636 | <!-- _______________________________________________________________________ --> |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1637 | <div class="doc_subsubsection"> |
| 1638 | <a name="i_switch">'<tt>switch</tt>' Instruction</a> |
| 1639 | </div> |
| 1640 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1641 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1642 | <h5>Syntax:</h5> |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1643 | |
| 1644 | <pre> |
| 1645 | switch <intty> <value>, label <defaultdest> [ <intty> <val>, label <dest> ... ] |
| 1646 | </pre> |
| 1647 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1648 | <h5>Overview:</h5> |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1649 | |
| 1650 | <p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of |
| 1651 | several different places. It is a generalization of the '<tt>br</tt>' |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1652 | instruction, allowing a branch to occur to one of many possible |
| 1653 | destinations.</p> |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1654 | |
| 1655 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1656 | <h5>Arguments:</h5> |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1657 | |
| 1658 | <p>The '<tt>switch</tt>' instruction uses three parameters: an integer |
| 1659 | comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and |
| 1660 | an array of pairs of comparison value constants and '<tt>label</tt>'s. The |
| 1661 | table is not allowed to contain duplicate constant entries.</p> |
| 1662 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1663 | <h5>Semantics:</h5> |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1664 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1665 | <p>The <tt>switch</tt> instruction specifies a table of values and |
| 1666 | destinations. When the '<tt>switch</tt>' instruction is executed, this |
John Criswell | 8411475 | 2004-06-25 16:05:06 +0000 | [diff] [blame] | 1667 | table is searched for the given value. If the value is found, control flow is |
| 1668 | transfered to the corresponding destination; otherwise, control flow is |
| 1669 | transfered to the default destination.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1670 | |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1671 | <h5>Implementation:</h5> |
| 1672 | |
| 1673 | <p>Depending on properties of the target machine and the particular |
| 1674 | <tt>switch</tt> instruction, this instruction may be code generated in different |
John Criswell | 8411475 | 2004-06-25 16:05:06 +0000 | [diff] [blame] | 1675 | ways. For example, it could be generated as a series of chained conditional |
| 1676 | branches or with a lookup table.</p> |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1677 | |
| 1678 | <h5>Example:</h5> |
| 1679 | |
| 1680 | <pre> |
| 1681 | <i>; Emulate a conditional br instruction</i> |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 1682 | %Val = <a href="#i_zext">zext</a> i1 %value to i32 |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1683 | switch i32 %Val, label %truedest [i32 0, label %falsedest ] |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1684 | |
| 1685 | <i>; Emulate an unconditional br instruction</i> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1686 | switch i32 0, label %dest [ ] |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1687 | |
| 1688 | <i>; Implement a jump table:</i> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1689 | switch i32 %val, label %otherwise [ i32 0, label %onzero |
| 1690 | i32 1, label %onone |
| 1691 | i32 2, label %ontwo ] |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1692 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1693 | </div> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1694 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1695 | <!-- _______________________________________________________________________ --> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1696 | <div class="doc_subsubsection"> |
| 1697 | <a name="i_invoke">'<tt>invoke</tt>' Instruction</a> |
| 1698 | </div> |
| 1699 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1700 | <div class="doc_text"> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1701 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1702 | <h5>Syntax:</h5> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1703 | |
| 1704 | <pre> |
| 1705 | <result> = invoke [<a href="#callingconv">cconv</a>] <ptr to function ty> %<function ptr val>(<function args>) |
Chris Lattner | 76b8a33 | 2006-05-14 18:23:06 +0000 | [diff] [blame] | 1706 | to label <normal label> unwind label <exception label> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1707 | </pre> |
| 1708 | |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1709 | <h5>Overview:</h5> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1710 | |
| 1711 | <p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified |
| 1712 | function, with the possibility of control flow transfer to either the |
John Criswell | e4c57cc | 2005-05-12 16:52:32 +0000 | [diff] [blame] | 1713 | '<tt>normal</tt>' label or the |
| 1714 | '<tt>exception</tt>' label. If the callee function returns with the |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1715 | "<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the |
| 1716 | "normal" label. If the callee (or any indirect callees) returns with the "<a |
John Criswell | e4c57cc | 2005-05-12 16:52:32 +0000 | [diff] [blame] | 1717 | href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and |
| 1718 | continued at the dynamically nearest "exception" label.</p> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1719 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1720 | <h5>Arguments:</h5> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1721 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1722 | <p>This instruction requires several arguments:</p> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1723 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1724 | <ol> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1725 | <li> |
Duncan Sands | 8036ca4 | 2007-03-30 12:22:09 +0000 | [diff] [blame] | 1726 | The optional "cconv" marker indicates which <a href="#callingconv">calling |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1727 | convention</a> the call should use. If none is specified, the call defaults |
| 1728 | to using C calling conventions. |
| 1729 | </li> |
| 1730 | <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to |
| 1731 | function value being invoked. In most cases, this is a direct function |
| 1732 | invocation, but indirect <tt>invoke</tt>s are just as possible, branching off |
| 1733 | an arbitrary pointer to function value. |
| 1734 | </li> |
| 1735 | |
| 1736 | <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a |
| 1737 | function to be invoked. </li> |
| 1738 | |
| 1739 | <li>'<tt>function args</tt>': argument list whose types match the function |
| 1740 | signature argument types. If the function signature indicates the function |
| 1741 | accepts a variable number of arguments, the extra arguments can be |
| 1742 | specified. </li> |
| 1743 | |
| 1744 | <li>'<tt>normal label</tt>': the label reached when the called function |
| 1745 | executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li> |
| 1746 | |
| 1747 | <li>'<tt>exception label</tt>': the label reached when a callee returns with |
| 1748 | the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li> |
| 1749 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1750 | </ol> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1751 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1752 | <h5>Semantics:</h5> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1753 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1754 | <p>This instruction is designed to operate as a standard '<tt><a |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1755 | href="#i_call">call</a></tt>' instruction in most regards. The primary |
| 1756 | difference is that it establishes an association with a label, which is used by |
| 1757 | the runtime library to unwind the stack.</p> |
| 1758 | |
| 1759 | <p>This instruction is used in languages with destructors to ensure that proper |
| 1760 | cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown |
| 1761 | exception. Additionally, this is important for implementation of |
| 1762 | '<tt>catch</tt>' clauses in high-level languages that support them.</p> |
| 1763 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1764 | <h5>Example:</h5> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1765 | <pre> |
Jeff Cohen | 6f1cc77 | 2007-04-22 01:17:39 +0000 | [diff] [blame] | 1766 | %retval = invoke i32 %Test(i32 15) to label %Continue |
| 1767 | unwind label %TestCleanup <i>; {i32}:retval set</i> |
| 1768 | %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue |
| 1769 | unwind label %TestCleanup <i>; {i32}:retval set</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1770 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1771 | </div> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1772 | |
| 1773 | |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1774 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1775 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1776 | <div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>' |
| 1777 | Instruction</a> </div> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1778 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1779 | <div class="doc_text"> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1780 | |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1781 | <h5>Syntax:</h5> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1782 | <pre> |
| 1783 | unwind |
| 1784 | </pre> |
| 1785 | |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1786 | <h5>Overview:</h5> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1787 | |
| 1788 | <p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow |
| 1789 | at the first callee in the dynamic call stack which used an <a |
| 1790 | href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is |
| 1791 | primarily used to implement exception handling.</p> |
| 1792 | |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1793 | <h5>Semantics:</h5> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1794 | |
| 1795 | <p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to |
| 1796 | immediately halt. The dynamic call stack is then searched for the first <a |
| 1797 | href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found, |
| 1798 | execution continues at the "exceptional" destination block specified by the |
| 1799 | <tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the |
| 1800 | dynamic call chain, undefined behavior results.</p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1801 | </div> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1802 | |
| 1803 | <!-- _______________________________________________________________________ --> |
| 1804 | |
| 1805 | <div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>' |
| 1806 | Instruction</a> </div> |
| 1807 | |
| 1808 | <div class="doc_text"> |
| 1809 | |
| 1810 | <h5>Syntax:</h5> |
| 1811 | <pre> |
| 1812 | unreachable |
| 1813 | </pre> |
| 1814 | |
| 1815 | <h5>Overview:</h5> |
| 1816 | |
| 1817 | <p>The '<tt>unreachable</tt>' instruction has no defined semantics. This |
| 1818 | instruction is used to inform the optimizer that a particular portion of the |
| 1819 | code is not reachable. This can be used to indicate that the code after a |
| 1820 | no-return function cannot be reached, and other facts.</p> |
| 1821 | |
| 1822 | <h5>Semantics:</h5> |
| 1823 | |
| 1824 | <p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p> |
| 1825 | </div> |
| 1826 | |
| 1827 | |
| 1828 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1829 | <!-- ======================================================================= --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1830 | <div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1831 | <div class="doc_text"> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1832 | <p>Binary operators are used to do most of the computation in a |
| 1833 | program. They require two operands, execute an operation on them, and |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 1834 | produce a single value. The operands might represent |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 1835 | multiple data, as is the case with the <a href="#t_vector">vector</a> data type. |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1836 | The result value of a binary operator is not |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1837 | necessarily the same type as its operands.</p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1838 | <p>There are several different binary operators:</p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1839 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1840 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1841 | <div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>' |
| 1842 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1843 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1844 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1845 | <pre> <result> = add <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1846 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1847 | <h5>Overview:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1848 | <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] | 1849 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1850 | <p>The two arguments to the '<tt>add</tt>' instruction must be either <a |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1851 | href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values. |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 1852 | This instruction can also take <a href="#t_vector">vector</a> versions of the values. |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1853 | Both arguments must have identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1854 | <h5>Semantics:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1855 | <p>The value produced is the integer or floating point sum of the two |
| 1856 | operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1857 | <h5>Example:</h5> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1858 | <pre> <result> = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1859 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1860 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1861 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1862 | <div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>' |
| 1863 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1864 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1865 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1866 | <pre> <result> = sub <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1867 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1868 | <h5>Overview:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1869 | <p>The '<tt>sub</tt>' instruction returns the difference of its two |
| 1870 | operands.</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1871 | <p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>' |
| 1872 | instruction present in most other intermediate representations.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1873 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1874 | <p>The two arguments to the '<tt>sub</tt>' instruction must be either <a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1875 | href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1876 | values. |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 1877 | This instruction can also take <a href="#t_vector">vector</a> versions of the values. |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1878 | Both arguments must have identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1879 | <h5>Semantics:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1880 | <p>The value produced is the integer or floating point difference of |
| 1881 | the two operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1882 | <h5>Example:</h5> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1883 | <pre> <result> = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i> |
| 1884 | <result> = sub i32 0, %val <i>; yields {i32}:result = -%var</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1885 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1886 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1887 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1888 | <div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>' |
| 1889 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1890 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1891 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1892 | <pre> <result> = mul <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1893 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1894 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1895 | <p>The '<tt>mul</tt>' instruction returns the product of its two |
| 1896 | operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1897 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1898 | <p>The two arguments to the '<tt>mul</tt>' instruction must be either <a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1899 | href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1900 | values. |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 1901 | This instruction can also take <a href="#t_vector">vector</a> versions of the values. |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1902 | Both arguments must have identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1903 | <h5>Semantics:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1904 | <p>The value produced is the integer or floating point product of the |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1905 | two operands.</p> |
Reid Spencer | a517338 | 2007-01-04 16:43:23 +0000 | [diff] [blame] | 1906 | <p>Because the operands are the same width, the result of an integer |
| 1907 | multiplication is the same whether the operands should be deemed unsigned or |
| 1908 | signed.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1909 | <h5>Example:</h5> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1910 | <pre> <result> = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1911 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1912 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1913 | <!-- _______________________________________________________________________ --> |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 1914 | <div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction |
| 1915 | </a></div> |
| 1916 | <div class="doc_text"> |
| 1917 | <h5>Syntax:</h5> |
| 1918 | <pre> <result> = udiv <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 1919 | </pre> |
| 1920 | <h5>Overview:</h5> |
| 1921 | <p>The '<tt>udiv</tt>' instruction returns the quotient of its two |
| 1922 | operands.</p> |
| 1923 | <h5>Arguments:</h5> |
| 1924 | <p>The two arguments to the '<tt>udiv</tt>' instruction must be |
| 1925 | <a href="#t_integer">integer</a> values. Both arguments must have identical |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 1926 | types. This instruction can also take <a href="#t_vector">vector</a> versions |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 1927 | of the values in which case the elements must be integers.</p> |
| 1928 | <h5>Semantics:</h5> |
| 1929 | <p>The value produced is the unsigned integer quotient of the two operands. This |
| 1930 | instruction always performs an unsigned division operation, regardless of |
| 1931 | whether the arguments are unsigned or not.</p> |
| 1932 | <h5>Example:</h5> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1933 | <pre> <result> = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i> |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 1934 | </pre> |
| 1935 | </div> |
| 1936 | <!-- _______________________________________________________________________ --> |
| 1937 | <div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction |
| 1938 | </a> </div> |
| 1939 | <div class="doc_text"> |
| 1940 | <h5>Syntax:</h5> |
| 1941 | <pre> <result> = sdiv <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 1942 | </pre> |
| 1943 | <h5>Overview:</h5> |
| 1944 | <p>The '<tt>sdiv</tt>' instruction returns the quotient of its two |
| 1945 | operands.</p> |
| 1946 | <h5>Arguments:</h5> |
| 1947 | <p>The two arguments to the '<tt>sdiv</tt>' instruction must be |
| 1948 | <a href="#t_integer">integer</a> values. Both arguments must have identical |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 1949 | types. This instruction can also take <a href="#t_vector">vector</a> versions |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 1950 | of the values in which case the elements must be integers.</p> |
| 1951 | <h5>Semantics:</h5> |
| 1952 | <p>The value produced is the signed integer quotient of the two operands. This |
| 1953 | instruction always performs a signed division operation, regardless of whether |
| 1954 | the arguments are signed or not.</p> |
| 1955 | <h5>Example:</h5> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1956 | <pre> <result> = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i> |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 1957 | </pre> |
| 1958 | </div> |
| 1959 | <!-- _______________________________________________________________________ --> |
| 1960 | <div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>' |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1961 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1962 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1963 | <h5>Syntax:</h5> |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 1964 | <pre> <result> = fdiv <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1965 | </pre> |
| 1966 | <h5>Overview:</h5> |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 1967 | <p>The '<tt>fdiv</tt>' instruction returns the quotient of its two |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1968 | operands.</p> |
| 1969 | <h5>Arguments:</h5> |
Jeff Cohen | 6f1cc77 | 2007-04-22 01:17:39 +0000 | [diff] [blame] | 1970 | <p>The two arguments to the '<tt>fdiv</tt>' instruction must be |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 1971 | <a href="#t_floating">floating point</a> values. Both arguments must have |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 1972 | identical types. This instruction can also take <a href="#t_vector">vector</a> |
Jeff Cohen | 6f1cc77 | 2007-04-22 01:17:39 +0000 | [diff] [blame] | 1973 | versions of floating point values.</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1974 | <h5>Semantics:</h5> |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 1975 | <p>The value produced is the floating point quotient of the two operands.</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1976 | <h5>Example:</h5> |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 1977 | <pre> <result> = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1978 | </pre> |
| 1979 | </div> |
| 1980 | <!-- _______________________________________________________________________ --> |
Reid Spencer | 0a783f7 | 2006-11-02 01:53:59 +0000 | [diff] [blame] | 1981 | <div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a> |
| 1982 | </div> |
| 1983 | <div class="doc_text"> |
| 1984 | <h5>Syntax:</h5> |
| 1985 | <pre> <result> = urem <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 1986 | </pre> |
| 1987 | <h5>Overview:</h5> |
| 1988 | <p>The '<tt>urem</tt>' instruction returns the remainder from the |
| 1989 | unsigned division of its two arguments.</p> |
| 1990 | <h5>Arguments:</h5> |
| 1991 | <p>The two arguments to the '<tt>urem</tt>' instruction must be |
| 1992 | <a href="#t_integer">integer</a> values. Both arguments must have identical |
| 1993 | types.</p> |
| 1994 | <h5>Semantics:</h5> |
| 1995 | <p>This instruction returns the unsigned integer <i>remainder</i> of a division. |
| 1996 | This instruction always performs an unsigned division to get the remainder, |
| 1997 | regardless of whether the arguments are unsigned or not.</p> |
| 1998 | <h5>Example:</h5> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 1999 | <pre> <result> = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i> |
Reid Spencer | 0a783f7 | 2006-11-02 01:53:59 +0000 | [diff] [blame] | 2000 | </pre> |
| 2001 | |
| 2002 | </div> |
| 2003 | <!-- _______________________________________________________________________ --> |
| 2004 | <div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>' |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2005 | Instruction</a> </div> |
| 2006 | <div class="doc_text"> |
| 2007 | <h5>Syntax:</h5> |
Reid Spencer | 0a783f7 | 2006-11-02 01:53:59 +0000 | [diff] [blame] | 2008 | <pre> <result> = srem <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2009 | </pre> |
| 2010 | <h5>Overview:</h5> |
Reid Spencer | 0a783f7 | 2006-11-02 01:53:59 +0000 | [diff] [blame] | 2011 | <p>The '<tt>srem</tt>' instruction returns the remainder from the |
| 2012 | signed division of its two operands.</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2013 | <h5>Arguments:</h5> |
Reid Spencer | 0a783f7 | 2006-11-02 01:53:59 +0000 | [diff] [blame] | 2014 | <p>The two arguments to the '<tt>srem</tt>' instruction must be |
| 2015 | <a href="#t_integer">integer</a> values. Both arguments must have identical |
| 2016 | types.</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2017 | <h5>Semantics:</h5> |
Reid Spencer | 0a783f7 | 2006-11-02 01:53:59 +0000 | [diff] [blame] | 2018 | <p>This instruction returns the <i>remainder</i> of a division (where the result |
Reid Spencer | c9fdfc8 | 2007-03-24 22:23:39 +0000 | [diff] [blame] | 2019 | has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i> |
| 2020 | operator (where the result has the same sign as the divisor, <tt>var2</tt>) of |
| 2021 | a value. For more information about the difference, see <a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2022 | href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The |
Reid Spencer | c9fdfc8 | 2007-03-24 22:23:39 +0000 | [diff] [blame] | 2023 | Math Forum</a>. For a table of how this is implemented in various languages, |
Reid Spencer | 64f5c6c | 2007-03-24 22:40:44 +0000 | [diff] [blame] | 2024 | please see <a href="http://en.wikipedia.org/wiki/Modulo_operation"> |
Reid Spencer | c9fdfc8 | 2007-03-24 22:23:39 +0000 | [diff] [blame] | 2025 | Wikipedia: modulo operation</a>.</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2026 | <h5>Example:</h5> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2027 | <pre> <result> = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i> |
Reid Spencer | 0a783f7 | 2006-11-02 01:53:59 +0000 | [diff] [blame] | 2028 | </pre> |
| 2029 | |
| 2030 | </div> |
| 2031 | <!-- _______________________________________________________________________ --> |
| 2032 | <div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>' |
| 2033 | Instruction</a> </div> |
| 2034 | <div class="doc_text"> |
| 2035 | <h5>Syntax:</h5> |
| 2036 | <pre> <result> = frem <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 2037 | </pre> |
| 2038 | <h5>Overview:</h5> |
| 2039 | <p>The '<tt>frem</tt>' instruction returns the remainder from the |
| 2040 | division of its two operands.</p> |
| 2041 | <h5>Arguments:</h5> |
| 2042 | <p>The two arguments to the '<tt>frem</tt>' instruction must be |
| 2043 | <a href="#t_floating">floating point</a> values. Both arguments must have |
| 2044 | identical types.</p> |
| 2045 | <h5>Semantics:</h5> |
| 2046 | <p>This instruction returns the <i>remainder</i> of a division.</p> |
| 2047 | <h5>Example:</h5> |
| 2048 | <pre> <result> = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2049 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2050 | </div> |
Robert Bocchino | 7b81c75 | 2006-02-17 21:18:08 +0000 | [diff] [blame] | 2051 | |
Reid Spencer | 8e11bf8 | 2007-02-02 13:57:07 +0000 | [diff] [blame] | 2052 | <!-- ======================================================================= --> |
| 2053 | <div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary |
| 2054 | Operations</a> </div> |
| 2055 | <div class="doc_text"> |
| 2056 | <p>Bitwise binary operators are used to do various forms of |
| 2057 | bit-twiddling in a program. They are generally very efficient |
| 2058 | instructions and can commonly be strength reduced from other |
| 2059 | instructions. They require two operands, execute an operation on them, |
| 2060 | and produce a single value. The resulting value of the bitwise binary |
| 2061 | operators is always the same type as its first operand.</p> |
| 2062 | </div> |
| 2063 | |
Reid Spencer | 569f2fa | 2007-01-31 21:39:12 +0000 | [diff] [blame] | 2064 | <!-- _______________________________________________________________________ --> |
| 2065 | <div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>' |
| 2066 | Instruction</a> </div> |
| 2067 | <div class="doc_text"> |
| 2068 | <h5>Syntax:</h5> |
| 2069 | <pre> <result> = shl <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 2070 | </pre> |
| 2071 | <h5>Overview:</h5> |
| 2072 | <p>The '<tt>shl</tt>' instruction returns the first operand shifted to |
| 2073 | the left a specified number of bits.</p> |
| 2074 | <h5>Arguments:</h5> |
| 2075 | <p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a |
| 2076 | href="#t_integer">integer</a> type.</p> |
| 2077 | <h5>Semantics:</h5> |
| 2078 | <p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p> |
| 2079 | <h5>Example:</h5><pre> |
| 2080 | <result> = shl i32 4, %var <i>; yields {i32}: 4 << %var</i> |
| 2081 | <result> = shl i32 4, 2 <i>; yields {i32}: 16</i> |
| 2082 | <result> = shl i32 1, 10 <i>; yields {i32}: 1024</i> |
| 2083 | </pre> |
| 2084 | </div> |
| 2085 | <!-- _______________________________________________________________________ --> |
| 2086 | <div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>' |
| 2087 | Instruction</a> </div> |
| 2088 | <div class="doc_text"> |
| 2089 | <h5>Syntax:</h5> |
| 2090 | <pre> <result> = lshr <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 2091 | </pre> |
| 2092 | |
| 2093 | <h5>Overview:</h5> |
| 2094 | <p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first |
Jeff Cohen | 6f1cc77 | 2007-04-22 01:17:39 +0000 | [diff] [blame] | 2095 | operand shifted to the right a specified number of bits with zero fill.</p> |
Reid Spencer | 569f2fa | 2007-01-31 21:39:12 +0000 | [diff] [blame] | 2096 | |
| 2097 | <h5>Arguments:</h5> |
| 2098 | <p>Both arguments to the '<tt>lshr</tt>' instruction must be the same |
| 2099 | <a href="#t_integer">integer</a> type.</p> |
| 2100 | |
| 2101 | <h5>Semantics:</h5> |
| 2102 | <p>This instruction always performs a logical shift right operation. The most |
| 2103 | significant bits of the result will be filled with zero bits after the |
| 2104 | shift.</p> |
| 2105 | |
| 2106 | <h5>Example:</h5> |
| 2107 | <pre> |
| 2108 | <result> = lshr i32 4, 1 <i>; yields {i32}:result = 2</i> |
| 2109 | <result> = lshr i32 4, 2 <i>; yields {i32}:result = 1</i> |
| 2110 | <result> = lshr i8 4, 3 <i>; yields {i8}:result = 0</i> |
| 2111 | <result> = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i> |
| 2112 | </pre> |
| 2113 | </div> |
| 2114 | |
Reid Spencer | 8e11bf8 | 2007-02-02 13:57:07 +0000 | [diff] [blame] | 2115 | <!-- _______________________________________________________________________ --> |
Reid Spencer | 569f2fa | 2007-01-31 21:39:12 +0000 | [diff] [blame] | 2116 | <div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>' |
| 2117 | Instruction</a> </div> |
| 2118 | <div class="doc_text"> |
| 2119 | |
| 2120 | <h5>Syntax:</h5> |
| 2121 | <pre> <result> = ashr <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 2122 | </pre> |
| 2123 | |
| 2124 | <h5>Overview:</h5> |
| 2125 | <p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first |
Jeff Cohen | 6f1cc77 | 2007-04-22 01:17:39 +0000 | [diff] [blame] | 2126 | operand shifted to the right a specified number of bits with sign extension.</p> |
Reid Spencer | 569f2fa | 2007-01-31 21:39:12 +0000 | [diff] [blame] | 2127 | |
| 2128 | <h5>Arguments:</h5> |
| 2129 | <p>Both arguments to the '<tt>ashr</tt>' instruction must be the same |
| 2130 | <a href="#t_integer">integer</a> type.</p> |
| 2131 | |
| 2132 | <h5>Semantics:</h5> |
| 2133 | <p>This instruction always performs an arithmetic shift right operation, |
| 2134 | The most significant bits of the result will be filled with the sign bit |
| 2135 | of <tt>var1</tt>.</p> |
| 2136 | |
| 2137 | <h5>Example:</h5> |
| 2138 | <pre> |
| 2139 | <result> = ashr i32 4, 1 <i>; yields {i32}:result = 2</i> |
| 2140 | <result> = ashr i32 4, 2 <i>; yields {i32}:result = 1</i> |
| 2141 | <result> = ashr i8 4, 3 <i>; yields {i8}:result = 0</i> |
| 2142 | <result> = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i> |
| 2143 | </pre> |
| 2144 | </div> |
| 2145 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2146 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2147 | <div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>' |
| 2148 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2149 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2150 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2151 | <pre> <result> = and <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2152 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2153 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2154 | <p>The '<tt>and</tt>' instruction returns the bitwise logical and of |
| 2155 | its two operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2156 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2157 | <p>The two arguments to the '<tt>and</tt>' instruction must be <a |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 2158 | href="#t_integer">integer</a> values. Both arguments must have |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2159 | identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2160 | <h5>Semantics:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2161 | <p>The truth table used for the '<tt>and</tt>' instruction is:</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2162 | <p> </p> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 2163 | <div style="align: center"> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2164 | <table border="1" cellspacing="0" cellpadding="4"> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2165 | <tbody> |
| 2166 | <tr> |
| 2167 | <td>In0</td> |
| 2168 | <td>In1</td> |
| 2169 | <td>Out</td> |
| 2170 | </tr> |
| 2171 | <tr> |
| 2172 | <td>0</td> |
| 2173 | <td>0</td> |
| 2174 | <td>0</td> |
| 2175 | </tr> |
| 2176 | <tr> |
| 2177 | <td>0</td> |
| 2178 | <td>1</td> |
| 2179 | <td>0</td> |
| 2180 | </tr> |
| 2181 | <tr> |
| 2182 | <td>1</td> |
| 2183 | <td>0</td> |
| 2184 | <td>0</td> |
| 2185 | </tr> |
| 2186 | <tr> |
| 2187 | <td>1</td> |
| 2188 | <td>1</td> |
| 2189 | <td>1</td> |
| 2190 | </tr> |
| 2191 | </tbody> |
| 2192 | </table> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 2193 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2194 | <h5>Example:</h5> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2195 | <pre> <result> = and i32 4, %var <i>; yields {i32}:result = 4 & %var</i> |
| 2196 | <result> = and i32 15, 40 <i>; yields {i32}:result = 8</i> |
| 2197 | <result> = and i32 4, 8 <i>; yields {i32}:result = 0</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2198 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2199 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2200 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2201 | <div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2202 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2203 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2204 | <pre> <result> = or <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2205 | </pre> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2206 | <h5>Overview:</h5> |
| 2207 | <p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive |
| 2208 | or of its two operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2209 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2210 | <p>The two arguments to the '<tt>or</tt>' instruction must be <a |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 2211 | href="#t_integer">integer</a> values. Both arguments must have |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2212 | identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2213 | <h5>Semantics:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2214 | <p>The truth table used for the '<tt>or</tt>' instruction is:</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2215 | <p> </p> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 2216 | <div style="align: center"> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2217 | <table border="1" cellspacing="0" cellpadding="4"> |
| 2218 | <tbody> |
| 2219 | <tr> |
| 2220 | <td>In0</td> |
| 2221 | <td>In1</td> |
| 2222 | <td>Out</td> |
| 2223 | </tr> |
| 2224 | <tr> |
| 2225 | <td>0</td> |
| 2226 | <td>0</td> |
| 2227 | <td>0</td> |
| 2228 | </tr> |
| 2229 | <tr> |
| 2230 | <td>0</td> |
| 2231 | <td>1</td> |
| 2232 | <td>1</td> |
| 2233 | </tr> |
| 2234 | <tr> |
| 2235 | <td>1</td> |
| 2236 | <td>0</td> |
| 2237 | <td>1</td> |
| 2238 | </tr> |
| 2239 | <tr> |
| 2240 | <td>1</td> |
| 2241 | <td>1</td> |
| 2242 | <td>1</td> |
| 2243 | </tr> |
| 2244 | </tbody> |
| 2245 | </table> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 2246 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2247 | <h5>Example:</h5> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2248 | <pre> <result> = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i> |
| 2249 | <result> = or i32 15, 40 <i>; yields {i32}:result = 47</i> |
| 2250 | <result> = or i32 4, 8 <i>; yields {i32}:result = 12</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2251 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2252 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2253 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2254 | <div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>' |
| 2255 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2256 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2257 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2258 | <pre> <result> = xor <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2259 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2260 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2261 | <p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive |
| 2262 | or of its two operands. The <tt>xor</tt> is used to implement the |
| 2263 | "one's complement" operation, which is the "~" operator in C.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2264 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2265 | <p>The two arguments to the '<tt>xor</tt>' instruction must be <a |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 2266 | href="#t_integer">integer</a> values. Both arguments must have |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2267 | identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2268 | <h5>Semantics:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2269 | <p>The truth table used for the '<tt>xor</tt>' instruction is:</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2270 | <p> </p> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 2271 | <div style="align: center"> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2272 | <table border="1" cellspacing="0" cellpadding="4"> |
| 2273 | <tbody> |
| 2274 | <tr> |
| 2275 | <td>In0</td> |
| 2276 | <td>In1</td> |
| 2277 | <td>Out</td> |
| 2278 | </tr> |
| 2279 | <tr> |
| 2280 | <td>0</td> |
| 2281 | <td>0</td> |
| 2282 | <td>0</td> |
| 2283 | </tr> |
| 2284 | <tr> |
| 2285 | <td>0</td> |
| 2286 | <td>1</td> |
| 2287 | <td>1</td> |
| 2288 | </tr> |
| 2289 | <tr> |
| 2290 | <td>1</td> |
| 2291 | <td>0</td> |
| 2292 | <td>1</td> |
| 2293 | </tr> |
| 2294 | <tr> |
| 2295 | <td>1</td> |
| 2296 | <td>1</td> |
| 2297 | <td>0</td> |
| 2298 | </tr> |
| 2299 | </tbody> |
| 2300 | </table> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 2301 | </div> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2302 | <p> </p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2303 | <h5>Example:</h5> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2304 | <pre> <result> = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i> |
| 2305 | <result> = xor i32 15, 40 <i>; yields {i32}:result = 39</i> |
| 2306 | <result> = xor i32 4, 8 <i>; yields {i32}:result = 12</i> |
| 2307 | <result> = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2308 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2309 | </div> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2310 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2311 | <!-- ======================================================================= --> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2312 | <div class="doc_subsection"> |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2313 | <a name="vectorops">Vector Operations</a> |
| 2314 | </div> |
| 2315 | |
| 2316 | <div class="doc_text"> |
| 2317 | |
| 2318 | <p>LLVM supports several instructions to represent vector operations in a |
Jeff Cohen | 6f1cc77 | 2007-04-22 01:17:39 +0000 | [diff] [blame] | 2319 | target-independent manner. These instructions cover the element-access and |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2320 | vector-specific operations needed to process vectors effectively. While LLVM |
| 2321 | does directly support these vector operations, many sophisticated algorithms |
| 2322 | will want to use target-specific intrinsics to take full advantage of a specific |
| 2323 | target.</p> |
| 2324 | |
| 2325 | </div> |
| 2326 | |
| 2327 | <!-- _______________________________________________________________________ --> |
| 2328 | <div class="doc_subsubsection"> |
| 2329 | <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a> |
| 2330 | </div> |
| 2331 | |
| 2332 | <div class="doc_text"> |
| 2333 | |
| 2334 | <h5>Syntax:</h5> |
| 2335 | |
| 2336 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2337 | <result> = extractelement <n x <ty>> <val>, i32 <idx> <i>; yields <ty></i> |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2338 | </pre> |
| 2339 | |
| 2340 | <h5>Overview:</h5> |
| 2341 | |
| 2342 | <p> |
| 2343 | The '<tt>extractelement</tt>' instruction extracts a single scalar |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 2344 | element from a vector at a specified index. |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2345 | </p> |
| 2346 | |
| 2347 | |
| 2348 | <h5>Arguments:</h5> |
| 2349 | |
| 2350 | <p> |
| 2351 | The first operand of an '<tt>extractelement</tt>' instruction is a |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 2352 | value of <a href="#t_vector">vector</a> type. The second operand is |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2353 | an index indicating the position from which to extract the element. |
| 2354 | The index may be a variable.</p> |
| 2355 | |
| 2356 | <h5>Semantics:</h5> |
| 2357 | |
| 2358 | <p> |
| 2359 | The result is a scalar of the same type as the element type of |
| 2360 | <tt>val</tt>. Its value is the value at position <tt>idx</tt> of |
| 2361 | <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the |
| 2362 | results are undefined. |
| 2363 | </p> |
| 2364 | |
| 2365 | <h5>Example:</h5> |
| 2366 | |
| 2367 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2368 | %result = extractelement <4 x i32> %vec, i32 0 <i>; yields i32</i> |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2369 | </pre> |
| 2370 | </div> |
| 2371 | |
| 2372 | |
| 2373 | <!-- _______________________________________________________________________ --> |
| 2374 | <div class="doc_subsubsection"> |
| 2375 | <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a> |
| 2376 | </div> |
| 2377 | |
| 2378 | <div class="doc_text"> |
| 2379 | |
| 2380 | <h5>Syntax:</h5> |
| 2381 | |
| 2382 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2383 | <result> = insertelement <n x <ty>> <val>, <ty> <elt>, i32 <idx> <i>; yields <n x <ty>></i> |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2384 | </pre> |
| 2385 | |
| 2386 | <h5>Overview:</h5> |
| 2387 | |
| 2388 | <p> |
| 2389 | The '<tt>insertelement</tt>' instruction inserts a scalar |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 2390 | element into a vector at a specified index. |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2391 | </p> |
| 2392 | |
| 2393 | |
| 2394 | <h5>Arguments:</h5> |
| 2395 | |
| 2396 | <p> |
| 2397 | The first operand of an '<tt>insertelement</tt>' instruction is a |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 2398 | value of <a href="#t_vector">vector</a> type. The second operand is a |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2399 | scalar value whose type must equal the element type of the first |
| 2400 | operand. The third operand is an index indicating the position at |
| 2401 | which to insert the value. The index may be a variable.</p> |
| 2402 | |
| 2403 | <h5>Semantics:</h5> |
| 2404 | |
| 2405 | <p> |
Reid Spencer | 485bad1 | 2007-02-15 03:07:05 +0000 | [diff] [blame] | 2406 | The result is a vector of the same type as <tt>val</tt>. Its |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2407 | element values are those of <tt>val</tt> except at position |
| 2408 | <tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt> |
| 2409 | exceeds the length of <tt>val</tt>, the results are undefined. |
| 2410 | </p> |
| 2411 | |
| 2412 | <h5>Example:</h5> |
| 2413 | |
| 2414 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2415 | %result = insertelement <4 x i32> %vec, i32 1, i32 0 <i>; yields <4 x i32></i> |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2416 | </pre> |
| 2417 | </div> |
| 2418 | |
| 2419 | <!-- _______________________________________________________________________ --> |
| 2420 | <div class="doc_subsubsection"> |
| 2421 | <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a> |
| 2422 | </div> |
| 2423 | |
| 2424 | <div class="doc_text"> |
| 2425 | |
| 2426 | <h5>Syntax:</h5> |
| 2427 | |
| 2428 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2429 | <result> = shufflevector <n x <ty>> <v1>, <n x <ty>> <v2>, <n x i32> <mask> <i>; yields <n x <ty>></i> |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2430 | </pre> |
| 2431 | |
| 2432 | <h5>Overview:</h5> |
| 2433 | |
| 2434 | <p> |
| 2435 | The '<tt>shufflevector</tt>' instruction constructs a permutation of elements |
| 2436 | from two input vectors, returning a vector of the same type. |
| 2437 | </p> |
| 2438 | |
| 2439 | <h5>Arguments:</h5> |
| 2440 | |
| 2441 | <p> |
| 2442 | The first two operands of a '<tt>shufflevector</tt>' instruction are vectors |
| 2443 | with types that match each other and types that match the result of the |
| 2444 | instruction. The third argument is a shuffle mask, which has the same number |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2445 | of elements as the other vector type, but whose element type is always 'i32'. |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2446 | </p> |
| 2447 | |
| 2448 | <p> |
| 2449 | The shuffle mask operand is required to be a constant vector with either |
| 2450 | constant integer or undef values. |
| 2451 | </p> |
| 2452 | |
| 2453 | <h5>Semantics:</h5> |
| 2454 | |
| 2455 | <p> |
| 2456 | The elements of the two input vectors are numbered from left to right across |
| 2457 | both of the vectors. The shuffle mask operand specifies, for each element of |
| 2458 | the result vector, which element of the two input registers the result element |
| 2459 | gets. The element selector may be undef (meaning "don't care") and the second |
| 2460 | operand may be undef if performing a shuffle from only one vector. |
| 2461 | </p> |
| 2462 | |
| 2463 | <h5>Example:</h5> |
| 2464 | |
| 2465 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2466 | %result = shufflevector <4 x i32> %v1, <4 x i32> %v2, |
Jeff Cohen | 6f1cc77 | 2007-04-22 01:17:39 +0000 | [diff] [blame] | 2467 | <4 x i32> <i32 0, i32 4, i32 1, i32 5> <i>; yields <4 x i32></i> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2468 | %result = shufflevector <4 x i32> %v1, <4 x i32> undef, |
| 2469 | <4 x i32> <i32 0, i32 1, i32 2, i32 3> <i>; yields <4 x i32></i> - Identity shuffle. |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2470 | </pre> |
| 2471 | </div> |
| 2472 | |
Tanya Lattner | 0947429 | 2006-04-14 19:24:33 +0000 | [diff] [blame] | 2473 | |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2474 | <!-- ======================================================================= --> |
| 2475 | <div class="doc_subsection"> |
Chris Lattner | 884a970 | 2006-08-15 00:45:58 +0000 | [diff] [blame] | 2476 | <a name="memoryops">Memory Access and Addressing Operations</a> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2477 | </div> |
| 2478 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2479 | <div class="doc_text"> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2480 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2481 | <p>A key design point of an SSA-based representation is how it |
| 2482 | represents memory. In LLVM, no memory locations are in SSA form, which |
| 2483 | makes things very simple. This section describes how to read, write, |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 2484 | allocate, and free memory in LLVM.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2485 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2486 | </div> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2487 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2488 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2489 | <div class="doc_subsubsection"> |
| 2490 | <a name="i_malloc">'<tt>malloc</tt>' Instruction</a> |
| 2491 | </div> |
| 2492 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2493 | <div class="doc_text"> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2494 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2495 | <h5>Syntax:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2496 | |
| 2497 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2498 | <result> = malloc <type>[, i32 <NumElements>][, align <alignment>] <i>; yields {type*}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2499 | </pre> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2500 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2501 | <h5>Overview:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2502 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2503 | <p>The '<tt>malloc</tt>' instruction allocates memory from the system |
| 2504 | heap and returns a pointer to it.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2505 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2506 | <h5>Arguments:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2507 | |
| 2508 | <p>The '<tt>malloc</tt>' instruction allocates |
| 2509 | <tt>sizeof(<type>)*NumElements</tt> |
John Criswell | 6e4ca61 | 2004-02-24 16:13:56 +0000 | [diff] [blame] | 2510 | bytes of memory from the operating system and returns a pointer of the |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2511 | appropriate type to the program. If "NumElements" is specified, it is the |
| 2512 | number of elements allocated. If an alignment is specified, the value result |
| 2513 | of the allocation is guaranteed to be aligned to at least that boundary. If |
| 2514 | not specified, or if zero, the target can choose to align the allocation on any |
| 2515 | convenient boundary.</p> |
| 2516 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2517 | <p>'<tt>type</tt>' must be a sized type.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2518 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2519 | <h5>Semantics:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2520 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2521 | <p>Memory is allocated using the system "<tt>malloc</tt>" function, and |
| 2522 | a pointer is returned.</p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2523 | |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2524 | <h5>Example:</h5> |
| 2525 | |
| 2526 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2527 | %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2528 | |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2529 | %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i> |
| 2530 | %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i> |
| 2531 | %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i> |
| 2532 | %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i> |
| 2533 | %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2534 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2535 | </div> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2536 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2537 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2538 | <div class="doc_subsubsection"> |
| 2539 | <a name="i_free">'<tt>free</tt>' Instruction</a> |
| 2540 | </div> |
| 2541 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2542 | <div class="doc_text"> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2543 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2544 | <h5>Syntax:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2545 | |
| 2546 | <pre> |
| 2547 | free <type> <value> <i>; yields {void}</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2548 | </pre> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2549 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2550 | <h5>Overview:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2551 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2552 | <p>The '<tt>free</tt>' instruction returns memory back to the unused |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 2553 | memory heap to be reallocated in the future.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2554 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2555 | <h5>Arguments:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2556 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2557 | <p>'<tt>value</tt>' shall be a pointer value that points to a value |
| 2558 | that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' |
| 2559 | instruction.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2560 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2561 | <h5>Semantics:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2562 | |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 2563 | <p>Access to the memory pointed to by the pointer is no longer defined |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2564 | after this instruction executes.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2565 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2566 | <h5>Example:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2567 | |
| 2568 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2569 | %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i> |
| 2570 | free [4 x i8]* %array |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2571 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2572 | </div> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2573 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2574 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2575 | <div class="doc_subsubsection"> |
| 2576 | <a name="i_alloca">'<tt>alloca</tt>' Instruction</a> |
| 2577 | </div> |
| 2578 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2579 | <div class="doc_text"> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2580 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2581 | <h5>Syntax:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2582 | |
| 2583 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2584 | <result> = alloca <type>[, i32 <NumElements>][, align <alignment>] <i>; yields {type*}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2585 | </pre> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2586 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2587 | <h5>Overview:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2588 | |
Jeff Cohen | 6f1cc77 | 2007-04-22 01:17:39 +0000 | [diff] [blame] | 2589 | <p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the |
| 2590 | currently executing function, to be automatically released when this function |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2591 | returns to its caller.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2592 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2593 | <h5>Arguments:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2594 | |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 2595 | <p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(<type>)*NumElements</tt> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2596 | bytes of memory on the runtime stack, returning a pointer of the |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2597 | appropriate type to the program. If "NumElements" is specified, it is the |
| 2598 | number of elements allocated. If an alignment is specified, the value result |
| 2599 | of the allocation is guaranteed to be aligned to at least that boundary. If |
| 2600 | not specified, or if zero, the target can choose to align the allocation on any |
| 2601 | convenient boundary.</p> |
| 2602 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2603 | <p>'<tt>type</tt>' may be any sized type.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2604 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2605 | <h5>Semantics:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2606 | |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 2607 | <p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2608 | memory is automatically released when the function returns. The '<tt>alloca</tt>' |
| 2609 | instruction is commonly used to represent automatic variables that must |
| 2610 | have an address available. When the function returns (either with the <tt><a |
John Criswell | dae2e93 | 2005-05-12 16:55:34 +0000 | [diff] [blame] | 2611 | href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2612 | instructions), the memory is reclaimed.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2613 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2614 | <h5>Example:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2615 | |
| 2616 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2617 | %ptr = alloca i32 <i>; yields {i32*}:ptr</i> |
| 2618 | %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i> |
| 2619 | %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i> |
| 2620 | %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2621 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2622 | </div> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2623 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2624 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2625 | <div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>' |
| 2626 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2627 | <div class="doc_text"> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2628 | <h5>Syntax:</h5> |
Christopher Lamb | 2330e4d | 2007-04-21 08:16:25 +0000 | [diff] [blame] | 2629 | <pre> <result> = load <ty>* <pointer>[, align <alignment>]<br> <result> = volatile load <ty>* <pointer>[, align <alignment>]<br></pre> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2630 | <h5>Overview:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2631 | <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] | 2632 | <h5>Arguments:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2633 | <p>The argument to the '<tt>load</tt>' instruction specifies the memory |
John Criswell | 0ec250c | 2005-10-24 16:17:18 +0000 | [diff] [blame] | 2634 | address from which to load. The pointer must point to a <a |
Chris Lattner | e53e508 | 2004-06-03 22:57:15 +0000 | [diff] [blame] | 2635 | href="#t_firstclass">first class</a> type. If the <tt>load</tt> is |
John Criswell | 0ec250c | 2005-10-24 16:17:18 +0000 | [diff] [blame] | 2636 | marked as <tt>volatile</tt>, then the optimizer is not allowed to modify |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2637 | the number or order of execution of this <tt>load</tt> with other |
| 2638 | volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt> |
| 2639 | instructions. </p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2640 | <h5>Semantics:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2641 | <p>The location of memory pointed to is loaded.</p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2642 | <h5>Examples:</h5> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2643 | <pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2644 | <a |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2645 | href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i> |
| 2646 | %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2647 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2648 | </div> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2649 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2650 | <div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>' |
| 2651 | Instruction</a> </div> |
Reid Spencer | 035ab57 | 2006-11-09 21:18:01 +0000 | [diff] [blame] | 2652 | <div class="doc_text"> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2653 | <h5>Syntax:</h5> |
Christopher Lamb | 2330e4d | 2007-04-21 08:16:25 +0000 | [diff] [blame] | 2654 | <pre> store <ty> <value>, <ty>* <pointer>[, align <alignment>] <i>; yields {void}</i> |
| 2655 | volatile store <ty> <value>, <ty>* <pointer>[, align <alignment>] <i>; yields {void}</i> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2656 | </pre> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2657 | <h5>Overview:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2658 | <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] | 2659 | <h5>Arguments:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2660 | <p>There are two arguments to the '<tt>store</tt>' instruction: a value |
Jeff Cohen | 6f1cc77 | 2007-04-22 01:17:39 +0000 | [diff] [blame] | 2661 | to store and an address at which to store it. The type of the '<tt><pointer></tt>' |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2662 | operand must be a pointer to the type of the '<tt><value></tt>' |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 2663 | operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2664 | optimizer is not allowed to modify the number or order of execution of |
| 2665 | this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a |
| 2666 | href="#i_store">store</a></tt> instructions.</p> |
| 2667 | <h5>Semantics:</h5> |
| 2668 | <p>The contents of memory are updated to contain '<tt><value></tt>' |
| 2669 | at the location specified by the '<tt><pointer></tt>' operand.</p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2670 | <h5>Example:</h5> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2671 | <pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2672 | <a |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2673 | href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i> |
| 2674 | %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2675 | </pre> |
Reid Spencer | 47ce179 | 2006-11-09 21:15:49 +0000 | [diff] [blame] | 2676 | </div> |
| 2677 | |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2678 | <!-- _______________________________________________________________________ --> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2679 | <div class="doc_subsubsection"> |
| 2680 | <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a> |
| 2681 | </div> |
| 2682 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2683 | <div class="doc_text"> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 2684 | <h5>Syntax:</h5> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2685 | <pre> |
| 2686 | <result> = getelementptr <ty>* <ptrval>{, <ty> <idx>}* |
| 2687 | </pre> |
| 2688 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 2689 | <h5>Overview:</h5> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2690 | |
| 2691 | <p> |
| 2692 | The '<tt>getelementptr</tt>' instruction is used to get the address of a |
| 2693 | subelement of an aggregate data structure.</p> |
| 2694 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 2695 | <h5>Arguments:</h5> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2696 | |
Reid Spencer | 85f5b5b | 2006-12-04 21:29:24 +0000 | [diff] [blame] | 2697 | <p>This instruction takes a list of integer operands that indicate what |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2698 | elements of the aggregate object to index to. The actual types of the arguments |
| 2699 | provided depend on the type of the first pointer argument. The |
| 2700 | '<tt>getelementptr</tt>' instruction is used to index down through the type |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 2701 | levels of a structure or to a specific index in an array. When indexing into a |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2702 | structure, only <tt>i32</tt> integer constants are allowed. When indexing |
Reid Spencer | 85f5b5b | 2006-12-04 21:29:24 +0000 | [diff] [blame] | 2703 | into an array or pointer, only integers of 32 or 64 bits are allowed, and will |
| 2704 | be sign extended to 64-bit values.</p> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2705 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2706 | <p>For example, let's consider a C code fragment and how it gets |
| 2707 | compiled to LLVM:</p> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2708 | |
| 2709 | <pre> |
| 2710 | struct RT { |
| 2711 | char A; |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2712 | i32 B[10][20]; |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2713 | char C; |
| 2714 | }; |
| 2715 | struct ST { |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2716 | i32 X; |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2717 | double Y; |
| 2718 | struct RT Z; |
| 2719 | }; |
| 2720 | |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2721 | define i32 *foo(struct ST *s) { |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2722 | return &s[1].Z.B[5][13]; |
| 2723 | } |
| 2724 | </pre> |
| 2725 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2726 | <p>The LLVM code generated by the GCC frontend is:</p> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2727 | |
| 2728 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2729 | %RT = type { i8 , [10 x [20 x i32]], i8 } |
| 2730 | %ST = type { i32, double, %RT } |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2731 | |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2732 | define i32* %foo(%ST* %s) { |
Brian Gaeke | 7283e7c | 2004-07-02 21:08:14 +0000 | [diff] [blame] | 2733 | entry: |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2734 | %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13 |
| 2735 | ret i32* %reg |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2736 | } |
| 2737 | </pre> |
| 2738 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 2739 | <h5>Semantics:</h5> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2740 | |
| 2741 | <p>The index types specified for the '<tt>getelementptr</tt>' instruction depend |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 2742 | on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a> |
Reid Spencer | 85f5b5b | 2006-12-04 21:29:24 +0000 | [diff] [blame] | 2743 | and <a href="#t_array">array</a> types can use a 32-bit or 64-bit |
Reid Spencer | 42ddd84 | 2006-12-03 16:53:48 +0000 | [diff] [blame] | 2744 | <a href="#t_integer">integer</a> type but the value will always be sign extended |
Jeff Cohen | 6f1cc77 | 2007-04-22 01:17:39 +0000 | [diff] [blame] | 2745 | to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt> |
Reid Spencer | 42ddd84 | 2006-12-03 16:53:48 +0000 | [diff] [blame] | 2746 | <b>constants</b>.</p> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2747 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2748 | <p>In the example above, the first index is indexing into the '<tt>%ST*</tt>' |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2749 | type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2750 | }</tt>' type, a structure. The second index indexes into the third element of |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2751 | the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]], |
| 2752 | i8 }</tt>' type, another structure. The third index indexes into the second |
| 2753 | element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2754 | array. The two dimensions of the array are subscripted into, yielding an |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2755 | '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer |
| 2756 | to this element, thus computing a value of '<tt>i32*</tt>' type.</p> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2757 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2758 | <p>Note that it is perfectly legal to index partially through a |
| 2759 | structure, returning a pointer to an inner element. Because of this, |
| 2760 | the LLVM code for the given testcase is equivalent to:</p> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2761 | |
| 2762 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2763 | define i32* %foo(%ST* %s) { |
| 2764 | %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i> |
Jeff Cohen | 6f1cc77 | 2007-04-22 01:17:39 +0000 | [diff] [blame] | 2765 | %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i> |
| 2766 | %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2767 | %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i> |
| 2768 | %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i> |
| 2769 | ret i32* %t5 |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2770 | } |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 2771 | </pre> |
Chris Lattner | e67a951 | 2005-06-24 17:22:57 +0000 | [diff] [blame] | 2772 | |
| 2773 | <p>Note that it is undefined to access an array out of bounds: array and |
| 2774 | pointer indexes must always be within the defined bounds of the array type. |
| 2775 | The one exception for this rules is zero length arrays. These arrays are |
| 2776 | defined to be accessible as variable length arrays, which requires access |
| 2777 | beyond the zero'th element.</p> |
| 2778 | |
Chris Lattner | 884a970 | 2006-08-15 00:45:58 +0000 | [diff] [blame] | 2779 | <p>The getelementptr instruction is often confusing. For some more insight |
| 2780 | into how it works, see <a href="GetElementPtr.html">the getelementptr |
| 2781 | FAQ</a>.</p> |
| 2782 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 2783 | <h5>Example:</h5> |
Chris Lattner | e67a951 | 2005-06-24 17:22:57 +0000 | [diff] [blame] | 2784 | |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2785 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2786 | <i>; yields [12 x i8]*:aptr</i> |
| 2787 | %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1 |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2788 | </pre> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2789 | </div> |
Reid Spencer | 47ce179 | 2006-11-09 21:15:49 +0000 | [diff] [blame] | 2790 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2791 | <!-- ======================================================================= --> |
Reid Spencer | 2fd21e6 | 2006-11-08 01:18:52 +0000 | [diff] [blame] | 2792 | <div class="doc_subsection"> <a name="convertops">Conversion Operations</a> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2793 | </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2794 | <div class="doc_text"> |
Reid Spencer | 2fd21e6 | 2006-11-08 01:18:52 +0000 | [diff] [blame] | 2795 | <p>The instructions in this category are the conversion instructions (casting) |
| 2796 | which all take a single operand and a type. They perform various bit conversions |
| 2797 | on the operand.</p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2798 | </div> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 2799 | |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 2800 | <!-- _______________________________________________________________________ --> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 2801 | <div class="doc_subsubsection"> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2802 | <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a> |
| 2803 | </div> |
| 2804 | <div class="doc_text"> |
| 2805 | |
| 2806 | <h5>Syntax:</h5> |
| 2807 | <pre> |
| 2808 | <result> = trunc <ty> <value> to <ty2> <i>; yields ty2</i> |
| 2809 | </pre> |
| 2810 | |
| 2811 | <h5>Overview:</h5> |
| 2812 | <p> |
| 2813 | The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>. |
| 2814 | </p> |
| 2815 | |
| 2816 | <h5>Arguments:</h5> |
| 2817 | <p> |
| 2818 | The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must |
| 2819 | be an <a href="#t_integer">integer</a> type, and a type that specifies the size |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 2820 | and type of the result, which must be an <a href="#t_integer">integer</a> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2821 | type. The bit size of <tt>value</tt> must be larger than the bit size of |
| 2822 | <tt>ty2</tt>. Equal sized types are not allowed.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2823 | |
| 2824 | <h5>Semantics:</h5> |
| 2825 | <p> |
| 2826 | The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2827 | and converts the remaining bits to <tt>ty2</tt>. Since the source size must be |
| 2828 | larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>. |
| 2829 | It will always truncate bits.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2830 | |
| 2831 | <h5>Example:</h5> |
| 2832 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2833 | %X = trunc i32 257 to i8 <i>; yields i8:1</i> |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 2834 | %Y = trunc i32 123 to i1 <i>; yields i1:true</i> |
| 2835 | %Y = trunc i32 122 to i1 <i>; yields i1:false</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2836 | </pre> |
| 2837 | </div> |
| 2838 | |
| 2839 | <!-- _______________________________________________________________________ --> |
| 2840 | <div class="doc_subsubsection"> |
| 2841 | <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a> |
| 2842 | </div> |
| 2843 | <div class="doc_text"> |
| 2844 | |
| 2845 | <h5>Syntax:</h5> |
| 2846 | <pre> |
| 2847 | <result> = zext <ty> <value> to <ty2> <i>; yields ty2</i> |
| 2848 | </pre> |
| 2849 | |
| 2850 | <h5>Overview:</h5> |
| 2851 | <p>The '<tt>zext</tt>' instruction zero extends its operand to type |
| 2852 | <tt>ty2</tt>.</p> |
| 2853 | |
| 2854 | |
| 2855 | <h5>Arguments:</h5> |
| 2856 | <p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 2857 | <a href="#t_integer">integer</a> type, and a type to cast it to, which must |
| 2858 | also be of <a href="#t_integer">integer</a> type. The bit size of the |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2859 | <tt>value</tt> must be smaller than the bit size of the destination type, |
| 2860 | <tt>ty2</tt>.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2861 | |
| 2862 | <h5>Semantics:</h5> |
| 2863 | <p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero |
| 2864 | bits until it reaches the size of the destination type, <tt>ty2</tt>. When the |
| 2865 | the operand and the type are the same size, no bit filling is done and the |
| 2866 | cast is considered a <i>no-op cast</i> because no bits change (only the type |
| 2867 | changes).</p> |
| 2868 | |
Reid Spencer | b592952 | 2007-01-12 15:46:11 +0000 | [diff] [blame] | 2869 | <p>When zero extending from i1, the result will always be either 0 or 1.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2870 | |
| 2871 | <h5>Example:</h5> |
| 2872 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2873 | %X = zext i32 257 to i64 <i>; yields i64:257</i> |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 2874 | %Y = zext i1 true to i32 <i>; yields i32:1</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2875 | </pre> |
| 2876 | </div> |
| 2877 | |
| 2878 | <!-- _______________________________________________________________________ --> |
| 2879 | <div class="doc_subsubsection"> |
| 2880 | <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a> |
| 2881 | </div> |
| 2882 | <div class="doc_text"> |
| 2883 | |
| 2884 | <h5>Syntax:</h5> |
| 2885 | <pre> |
| 2886 | <result> = sext <ty> <value> to <ty2> <i>; yields ty2</i> |
| 2887 | </pre> |
| 2888 | |
| 2889 | <h5>Overview:</h5> |
| 2890 | <p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p> |
| 2891 | |
| 2892 | <h5>Arguments:</h5> |
| 2893 | <p> |
| 2894 | The '<tt>sext</tt>' instruction takes a value to cast, which must be of |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 2895 | <a href="#t_integer">integer</a> type, and a type to cast it to, which must |
| 2896 | also be of <a href="#t_integer">integer</a> type. The bit size of the |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2897 | <tt>value</tt> must be smaller than the bit size of the destination type, |
| 2898 | <tt>ty2</tt>.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2899 | |
| 2900 | <h5>Semantics:</h5> |
| 2901 | <p> |
| 2902 | The '<tt>sext</tt>' instruction performs a sign extension by copying the sign |
| 2903 | bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of |
| 2904 | the type <tt>ty2</tt>. When the the operand and the type are the same size, |
| 2905 | no bit filling is done and the cast is considered a <i>no-op cast</i> because |
| 2906 | no bits change (only the type changes).</p> |
| 2907 | |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 2908 | <p>When sign extending from i1, the extension always results in -1 or 0.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2909 | |
| 2910 | <h5>Example:</h5> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2911 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 2912 | %X = sext i8 -1 to i16 <i>; yields i16 :65535</i> |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 2913 | %Y = sext i1 true to i32 <i>; yields i32:-1</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2914 | </pre> |
| 2915 | </div> |
| 2916 | |
| 2917 | <!-- _______________________________________________________________________ --> |
| 2918 | <div class="doc_subsubsection"> |
Reid Spencer | 3fa91b0 | 2006-11-09 21:48:10 +0000 | [diff] [blame] | 2919 | <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a> |
| 2920 | </div> |
| 2921 | |
| 2922 | <div class="doc_text"> |
| 2923 | |
| 2924 | <h5>Syntax:</h5> |
| 2925 | |
| 2926 | <pre> |
| 2927 | <result> = fptrunc <ty> <value> to <ty2> <i>; yields ty2</i> |
| 2928 | </pre> |
| 2929 | |
| 2930 | <h5>Overview:</h5> |
| 2931 | <p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type |
| 2932 | <tt>ty2</tt>.</p> |
| 2933 | |
| 2934 | |
| 2935 | <h5>Arguments:</h5> |
| 2936 | <p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating |
| 2937 | point</a> value to cast and a <a href="#t_floating">floating point</a> type to |
| 2938 | cast it to. The size of <tt>value</tt> must be larger than the size of |
| 2939 | <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a |
| 2940 | <i>no-op cast</i>.</p> |
| 2941 | |
| 2942 | <h5>Semantics:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2943 | <p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger |
| 2944 | <a href="#t_floating">floating point</a> type to a smaller |
| 2945 | <a href="#t_floating">floating point</a> type. If the value cannot fit within |
| 2946 | the destination type, <tt>ty2</tt>, then the results are undefined.</p> |
Reid Spencer | 3fa91b0 | 2006-11-09 21:48:10 +0000 | [diff] [blame] | 2947 | |
| 2948 | <h5>Example:</h5> |
| 2949 | <pre> |
| 2950 | %X = fptrunc double 123.0 to float <i>; yields float:123.0</i> |
| 2951 | %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i> |
| 2952 | </pre> |
| 2953 | </div> |
| 2954 | |
| 2955 | <!-- _______________________________________________________________________ --> |
| 2956 | <div class="doc_subsubsection"> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2957 | <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a> |
| 2958 | </div> |
| 2959 | <div class="doc_text"> |
| 2960 | |
| 2961 | <h5>Syntax:</h5> |
| 2962 | <pre> |
| 2963 | <result> = fpext <ty> <value> to <ty2> <i>; yields ty2</i> |
| 2964 | </pre> |
| 2965 | |
| 2966 | <h5>Overview:</h5> |
| 2967 | <p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger |
| 2968 | floating point value.</p> |
| 2969 | |
| 2970 | <h5>Arguments:</h5> |
| 2971 | <p>The '<tt>fpext</tt>' instruction takes a |
| 2972 | <a href="#t_floating">floating point</a> <tt>value</tt> to cast, |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2973 | and a <a href="#t_floating">floating point</a> type to cast it to. The source |
| 2974 | type must be smaller than the destination type.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2975 | |
| 2976 | <h5>Semantics:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2977 | <p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller |
Duncan Sands | 8036ca4 | 2007-03-30 12:22:09 +0000 | [diff] [blame] | 2978 | <a href="#t_floating">floating point</a> type to a larger |
| 2979 | <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2980 | used to make a <i>no-op cast</i> because it always changes bits. Use |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 2981 | <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2982 | |
| 2983 | <h5>Example:</h5> |
| 2984 | <pre> |
| 2985 | %X = fpext float 3.1415 to double <i>; yields double:3.1415</i> |
| 2986 | %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i> |
| 2987 | </pre> |
| 2988 | </div> |
| 2989 | |
| 2990 | <!-- _______________________________________________________________________ --> |
| 2991 | <div class="doc_subsubsection"> |
Reid Spencer | 24d6da5 | 2007-01-21 00:29:26 +0000 | [diff] [blame] | 2992 | <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2993 | </div> |
| 2994 | <div class="doc_text"> |
| 2995 | |
| 2996 | <h5>Syntax:</h5> |
| 2997 | <pre> |
| 2998 | <result> = fp2uint <ty> <value> to <ty2> <i>; yields ty2</i> |
| 2999 | </pre> |
| 3000 | |
| 3001 | <h5>Overview:</h5> |
| 3002 | <p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its |
| 3003 | unsigned integer equivalent of type <tt>ty2</tt>. |
| 3004 | </p> |
| 3005 | |
| 3006 | <h5>Arguments:</h5> |
| 3007 | <p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a |
| 3008 | <a href="#t_floating">floating point</a> value, and a type to cast it to, which |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 3009 | must be an <a href="#t_integer">integer</a> type.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3010 | |
| 3011 | <h5>Semantics:</h5> |
| 3012 | <p> The '<tt>fp2uint</tt>' instruction converts its |
| 3013 | <a href="#t_floating">floating point</a> operand into the nearest (rounding |
| 3014 | towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>, |
| 3015 | the results are undefined.</p> |
| 3016 | |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 3017 | <p>When converting to i1, the conversion is done as a comparison against |
| 3018 | zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>. |
| 3019 | If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3020 | |
| 3021 | <h5>Example:</h5> |
| 3022 | <pre> |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 3023 | %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i> |
| 3024 | %Y = fp2uint float 1.0E+300 to i1 <i>; yields i1:true</i> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 3025 | %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3026 | </pre> |
| 3027 | </div> |
| 3028 | |
| 3029 | <!-- _______________________________________________________________________ --> |
| 3030 | <div class="doc_subsubsection"> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 3031 | <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3032 | </div> |
| 3033 | <div class="doc_text"> |
| 3034 | |
| 3035 | <h5>Syntax:</h5> |
| 3036 | <pre> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 3037 | <result> = fptosi <ty> <value> to <ty2> <i>; yields ty2</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3038 | </pre> |
| 3039 | |
| 3040 | <h5>Overview:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 3041 | <p>The '<tt>fptosi</tt>' instruction converts |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3042 | <a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>. |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 3043 | </p> |
| 3044 | |
| 3045 | |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 3046 | <h5>Arguments:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 3047 | <p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3048 | <a href="#t_floating">floating point</a> value, and a type to cast it to, which |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 3049 | must also be an <a href="#t_integer">integer</a> type.</p> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 3050 | |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 3051 | <h5>Semantics:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 3052 | <p>The '<tt>fptosi</tt>' instruction converts its |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3053 | <a href="#t_floating">floating point</a> operand into the nearest (rounding |
| 3054 | towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>, |
| 3055 | the results are undefined.</p> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 3056 | |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 3057 | <p>When converting to i1, the conversion is done as a comparison against |
| 3058 | zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>. |
| 3059 | If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 3060 | |
Chris Lattner | 33ba0d9 | 2001-07-09 00:26:23 +0000 | [diff] [blame] | 3061 | <h5>Example:</h5> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 3062 | <pre> |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 3063 | %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i> |
| 3064 | %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 3065 | %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3066 | </pre> |
| 3067 | </div> |
| 3068 | |
| 3069 | <!-- _______________________________________________________________________ --> |
| 3070 | <div class="doc_subsubsection"> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 3071 | <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3072 | </div> |
| 3073 | <div class="doc_text"> |
| 3074 | |
| 3075 | <h5>Syntax:</h5> |
| 3076 | <pre> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 3077 | <result> = uitofp <ty> <value> to <ty2> <i>; yields ty2</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3078 | </pre> |
| 3079 | |
| 3080 | <h5>Overview:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 3081 | <p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3082 | integer and converts that value to the <tt>ty2</tt> type.</p> |
| 3083 | |
| 3084 | |
| 3085 | <h5>Arguments:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 3086 | <p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be an |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 3087 | <a href="#t_integer">integer</a> value, and a type to cast it to, which must |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3088 | be a <a href="#t_floating">floating point</a> type.</p> |
| 3089 | |
| 3090 | <h5>Semantics:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 3091 | <p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3092 | integer quantity and converts it to the corresponding floating point value. If |
Jeff Cohen | cb75731 | 2007-04-22 14:56:37 +0000 | [diff] [blame] | 3093 | the value cannot fit in the floating point value, the results are undefined.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3094 | |
| 3095 | |
| 3096 | <h5>Example:</h5> |
| 3097 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 3098 | %X = uitofp i32 257 to float <i>; yields float:257.0</i> |
| 3099 | %Y = uitofp i8 -1 to double <i>; yields double:255.0</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3100 | </pre> |
| 3101 | </div> |
| 3102 | |
| 3103 | <!-- _______________________________________________________________________ --> |
| 3104 | <div class="doc_subsubsection"> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 3105 | <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3106 | </div> |
| 3107 | <div class="doc_text"> |
| 3108 | |
| 3109 | <h5>Syntax:</h5> |
| 3110 | <pre> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 3111 | <result> = sitofp <ty> <value> to <ty2> <i>; yields ty2</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3112 | </pre> |
| 3113 | |
| 3114 | <h5>Overview:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 3115 | <p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3116 | integer and converts that value to the <tt>ty2</tt> type.</p> |
| 3117 | |
| 3118 | <h5>Arguments:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 3119 | <p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be an |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 3120 | <a href="#t_integer">integer</a> value, and a type to cast it to, which must be |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3121 | a <a href="#t_floating">floating point</a> type.</p> |
| 3122 | |
| 3123 | <h5>Semantics:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 3124 | <p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3125 | integer quantity and converts it to the corresponding floating point value. If |
Jeff Cohen | cb75731 | 2007-04-22 14:56:37 +0000 | [diff] [blame] | 3126 | the value cannot fit in the floating point value, the results are undefined.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3127 | |
| 3128 | <h5>Example:</h5> |
| 3129 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 3130 | %X = sitofp i32 257 to float <i>; yields float:257.0</i> |
| 3131 | %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3132 | </pre> |
| 3133 | </div> |
| 3134 | |
| 3135 | <!-- _______________________________________________________________________ --> |
| 3136 | <div class="doc_subsubsection"> |
Reid Spencer | 7267925 | 2006-11-11 21:00:47 +0000 | [diff] [blame] | 3137 | <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a> |
| 3138 | </div> |
| 3139 | <div class="doc_text"> |
| 3140 | |
| 3141 | <h5>Syntax:</h5> |
| 3142 | <pre> |
| 3143 | <result> = ptrtoint <ty> <value> to <ty2> <i>; yields ty2</i> |
| 3144 | </pre> |
| 3145 | |
| 3146 | <h5>Overview:</h5> |
| 3147 | <p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to |
| 3148 | the integer type <tt>ty2</tt>.</p> |
| 3149 | |
| 3150 | <h5>Arguments:</h5> |
| 3151 | <p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which |
Duncan Sands | 8036ca4 | 2007-03-30 12:22:09 +0000 | [diff] [blame] | 3152 | must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to |
Reid Spencer | 7267925 | 2006-11-11 21:00:47 +0000 | [diff] [blame] | 3153 | <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type. |
| 3154 | |
| 3155 | <h5>Semantics:</h5> |
| 3156 | <p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type |
| 3157 | <tt>ty2</tt> by interpreting the pointer value as an integer and either |
| 3158 | truncating or zero extending that value to the size of the integer type. If |
| 3159 | <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If |
| 3160 | <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they |
| 3161 | are the same size, then nothing is done (<i>no-op cast</i>).</p> |
| 3162 | |
| 3163 | <h5>Example:</h5> |
| 3164 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 3165 | %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit</i> |
| 3166 | %Y = ptrtoint i32* %x to i64 <i>; yields zero extend on 32-bit</i> |
Reid Spencer | 7267925 | 2006-11-11 21:00:47 +0000 | [diff] [blame] | 3167 | </pre> |
| 3168 | </div> |
| 3169 | |
| 3170 | <!-- _______________________________________________________________________ --> |
| 3171 | <div class="doc_subsubsection"> |
| 3172 | <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a> |
| 3173 | </div> |
| 3174 | <div class="doc_text"> |
| 3175 | |
| 3176 | <h5>Syntax:</h5> |
| 3177 | <pre> |
| 3178 | <result> = inttoptr <ty> <value> to <ty2> <i>; yields ty2</i> |
| 3179 | </pre> |
| 3180 | |
| 3181 | <h5>Overview:</h5> |
| 3182 | <p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to |
| 3183 | a pointer type, <tt>ty2</tt>.</p> |
| 3184 | |
| 3185 | <h5>Arguments:</h5> |
Duncan Sands | 8036ca4 | 2007-03-30 12:22:09 +0000 | [diff] [blame] | 3186 | <p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a> |
Reid Spencer | 7267925 | 2006-11-11 21:00:47 +0000 | [diff] [blame] | 3187 | value to cast, and a type to cast it to, which must be a |
Anton Korobeynikov | 7f70559 | 2007-01-12 19:20:47 +0000 | [diff] [blame] | 3188 | <a href="#t_pointer">pointer</a> type. |
Reid Spencer | 7267925 | 2006-11-11 21:00:47 +0000 | [diff] [blame] | 3189 | |
| 3190 | <h5>Semantics:</h5> |
| 3191 | <p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type |
| 3192 | <tt>ty2</tt> by applying either a zero extension or a truncation depending on |
| 3193 | the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the |
| 3194 | size of a pointer then a truncation is done. If <tt>value</tt> is smaller than |
| 3195 | the size of a pointer then a zero extension is done. If they are the same size, |
| 3196 | nothing is done (<i>no-op cast</i>).</p> |
| 3197 | |
| 3198 | <h5>Example:</h5> |
| 3199 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 3200 | %X = inttoptr i32 255 to i32* <i>; yields zero extend on 64-bit</i> |
| 3201 | %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit </i> |
| 3202 | %Y = inttoptr i16 0 to i32* <i>; yields zero extend on 32-bit</i> |
Reid Spencer | 7267925 | 2006-11-11 21:00:47 +0000 | [diff] [blame] | 3203 | </pre> |
| 3204 | </div> |
| 3205 | |
| 3206 | <!-- _______________________________________________________________________ --> |
| 3207 | <div class="doc_subsubsection"> |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 3208 | <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3209 | </div> |
| 3210 | <div class="doc_text"> |
| 3211 | |
| 3212 | <h5>Syntax:</h5> |
| 3213 | <pre> |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 3214 | <result> = bitcast <ty> <value> to <ty2> <i>; yields ty2</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3215 | </pre> |
| 3216 | |
| 3217 | <h5>Overview:</h5> |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 3218 | <p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3219 | <tt>ty2</tt> without changing any bits.</p> |
| 3220 | |
| 3221 | <h5>Arguments:</h5> |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 3222 | <p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3223 | a first class value, and a type to cast it to, which must also be a <a |
| 3224 | href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt> |
Reid Spencer | 19b569f | 2007-01-09 20:08:58 +0000 | [diff] [blame] | 3225 | and the destination type, <tt>ty2</tt>, must be identical. If the source |
| 3226 | type is a pointer, the destination type must also be a pointer.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3227 | |
| 3228 | <h5>Semantics:</h5> |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 3229 | <p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type |
Reid Spencer | 7267925 | 2006-11-11 21:00:47 +0000 | [diff] [blame] | 3230 | <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with |
| 3231 | this conversion. The conversion is done as if the <tt>value</tt> had been |
| 3232 | stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be |
| 3233 | converted to other pointer types with this instruction. To convert pointers to |
| 3234 | other types, use the <a href="#i_inttoptr">inttoptr</a> or |
| 3235 | <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3236 | |
| 3237 | <h5>Example:</h5> |
| 3238 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 3239 | %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i> |
| 3240 | %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i> |
| 3241 | %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i> |
Chris Lattner | 33ba0d9 | 2001-07-09 00:26:23 +0000 | [diff] [blame] | 3242 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3243 | </div> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 3244 | |
Reid Spencer | 2fd21e6 | 2006-11-08 01:18:52 +0000 | [diff] [blame] | 3245 | <!-- ======================================================================= --> |
| 3246 | <div class="doc_subsection"> <a name="otherops">Other Operations</a> </div> |
| 3247 | <div class="doc_text"> |
| 3248 | <p>The instructions in this category are the "miscellaneous" |
| 3249 | instructions, which defy better classification.</p> |
| 3250 | </div> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3251 | |
| 3252 | <!-- _______________________________________________________________________ --> |
| 3253 | <div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a> |
| 3254 | </div> |
| 3255 | <div class="doc_text"> |
| 3256 | <h5>Syntax:</h5> |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 3257 | <pre> <result> = icmp <cond> <ty> <var1>, <var2> |
| 3258 | <i>; yields {i1}:result</i> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3259 | </pre> |
| 3260 | <h5>Overview:</h5> |
| 3261 | <p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison |
| 3262 | of its two integer operands.</p> |
| 3263 | <h5>Arguments:</h5> |
| 3264 | <p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is |
| 3265 | the condition code which indicates the kind of comparison to perform. It is not |
| 3266 | a value, just a keyword. The possibilities for the condition code are: |
| 3267 | <ol> |
| 3268 | <li><tt>eq</tt>: equal</li> |
| 3269 | <li><tt>ne</tt>: not equal </li> |
| 3270 | <li><tt>ugt</tt>: unsigned greater than</li> |
| 3271 | <li><tt>uge</tt>: unsigned greater or equal</li> |
| 3272 | <li><tt>ult</tt>: unsigned less than</li> |
| 3273 | <li><tt>ule</tt>: unsigned less or equal</li> |
| 3274 | <li><tt>sgt</tt>: signed greater than</li> |
| 3275 | <li><tt>sge</tt>: signed greater or equal</li> |
| 3276 | <li><tt>slt</tt>: signed less than</li> |
| 3277 | <li><tt>sle</tt>: signed less or equal</li> |
| 3278 | </ol> |
Chris Lattner | 3b19d65 | 2007-01-15 01:54:13 +0000 | [diff] [blame] | 3279 | <p>The remaining two arguments must be <a href="#t_integer">integer</a> or |
Reid Spencer | 350f8aa | 2007-01-04 05:19:58 +0000 | [diff] [blame] | 3280 | <a href="#t_pointer">pointer</a> typed. They must also be identical types.</p> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3281 | <h5>Semantics:</h5> |
| 3282 | <p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to |
| 3283 | the condition code given as <tt>cond</tt>. The comparison performed always |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 3284 | yields a <a href="#t_primitive">i1</a> result, as follows: |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3285 | <ol> |
| 3286 | <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal, |
| 3287 | <tt>false</tt> otherwise. No sign interpretation is necessary or performed. |
| 3288 | </li> |
| 3289 | <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal, |
| 3290 | <tt>false</tt> otherwise. No sign interpretation is necessary or performed. |
| 3291 | <li><tt>ugt</tt>: interprets the operands as unsigned values and yields |
| 3292 | <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li> |
| 3293 | <li><tt>uge</tt>: interprets the operands as unsigned values and yields |
| 3294 | <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li> |
| 3295 | <li><tt>ult</tt>: interprets the operands as unsigned values and yields |
| 3296 | <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li> |
| 3297 | <li><tt>ule</tt>: interprets the operands as unsigned values and yields |
| 3298 | <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li> |
| 3299 | <li><tt>sgt</tt>: interprets the operands as signed values and yields |
| 3300 | <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li> |
| 3301 | <li><tt>sge</tt>: interprets the operands as signed values and yields |
| 3302 | <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li> |
| 3303 | <li><tt>slt</tt>: interprets the operands as signed values and yields |
| 3304 | <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li> |
| 3305 | <li><tt>sle</tt>: interprets the operands as signed values and yields |
| 3306 | <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3307 | </ol> |
| 3308 | <p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer |
| 3309 | values are treated as integers and then compared.</p> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3310 | |
| 3311 | <h5>Example:</h5> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 3312 | <pre> <result> = icmp eq i32 4, 5 <i>; yields: result=false</i> |
| 3313 | <result> = icmp ne float* %X, %X <i>; yields: result=false</i> |
| 3314 | <result> = icmp ult i16 4, 5 <i>; yields: result=true</i> |
| 3315 | <result> = icmp sgt i16 4, 5 <i>; yields: result=false</i> |
| 3316 | <result> = icmp ule i16 -4, 5 <i>; yields: result=false</i> |
| 3317 | <result> = icmp sge i16 4, 5 <i>; yields: result=false</i> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3318 | </pre> |
| 3319 | </div> |
| 3320 | |
| 3321 | <!-- _______________________________________________________________________ --> |
| 3322 | <div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a> |
| 3323 | </div> |
| 3324 | <div class="doc_text"> |
| 3325 | <h5>Syntax:</h5> |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 3326 | <pre> <result> = fcmp <cond> <ty> <var1>, <var2> |
| 3327 | <i>; yields {i1}:result</i> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3328 | </pre> |
| 3329 | <h5>Overview:</h5> |
| 3330 | <p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison |
| 3331 | of its floating point operands.</p> |
| 3332 | <h5>Arguments:</h5> |
| 3333 | <p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is |
| 3334 | the condition code which indicates the kind of comparison to perform. It is not |
| 3335 | a value, just a keyword. The possibilities for the condition code are: |
| 3336 | <ol> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3337 | <li><tt>false</tt>: no comparison, always returns false</li> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3338 | <li><tt>oeq</tt>: ordered and equal</li> |
| 3339 | <li><tt>ogt</tt>: ordered and greater than </li> |
| 3340 | <li><tt>oge</tt>: ordered and greater than or equal</li> |
| 3341 | <li><tt>olt</tt>: ordered and less than </li> |
| 3342 | <li><tt>ole</tt>: ordered and less than or equal</li> |
| 3343 | <li><tt>one</tt>: ordered and not equal</li> |
| 3344 | <li><tt>ord</tt>: ordered (no nans)</li> |
| 3345 | <li><tt>ueq</tt>: unordered or equal</li> |
| 3346 | <li><tt>ugt</tt>: unordered or greater than </li> |
| 3347 | <li><tt>uge</tt>: unordered or greater than or equal</li> |
| 3348 | <li><tt>ult</tt>: unordered or less than </li> |
| 3349 | <li><tt>ule</tt>: unordered or less than or equal</li> |
| 3350 | <li><tt>une</tt>: unordered or not equal</li> |
| 3351 | <li><tt>uno</tt>: unordered (either nans)</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3352 | <li><tt>true</tt>: no comparison, always returns true</li> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3353 | </ol> |
Reid Spencer | 93a4985 | 2006-12-06 07:08:07 +0000 | [diff] [blame] | 3354 | <p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while |
| 3355 | <i>unordered</i> means that either operand may be a QNAN.</p> |
Reid Spencer | 350f8aa | 2007-01-04 05:19:58 +0000 | [diff] [blame] | 3356 | <p>The <tt>val1</tt> and <tt>val2</tt> arguments must be |
| 3357 | <a href="#t_floating">floating point</a> typed. They must have identical |
| 3358 | types.</p> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3359 | <p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and |
| 3360 | <i>unordered</i> means that either operand is a QNAN.</p> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3361 | <h5>Semantics:</h5> |
| 3362 | <p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to |
| 3363 | the condition code given as <tt>cond</tt>. The comparison performed always |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 3364 | yields a <a href="#t_primitive">i1</a> result, as follows: |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3365 | <ol> |
| 3366 | <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3367 | <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3368 | <tt>var1</tt> is equal to <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3369 | <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3370 | <tt>var1</tt> is greather than <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3371 | <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3372 | <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3373 | <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3374 | <tt>var1</tt> is less than <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3375 | <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3376 | <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3377 | <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3378 | <tt>var1</tt> is not equal to <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3379 | <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li> |
| 3380 | <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3381 | <tt>var1</tt> is equal to <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3382 | <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3383 | <tt>var1</tt> is greater than <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3384 | <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3385 | <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3386 | <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3387 | <tt>var1</tt> is less than <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3388 | <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3389 | <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3390 | <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3391 | <tt>var1</tt> is not equal to <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3392 | <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3393 | <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li> |
| 3394 | </ol> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3395 | |
| 3396 | <h5>Example:</h5> |
| 3397 | <pre> <result> = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i> |
| 3398 | <result> = icmp one float 4.0, 5.0 <i>; yields: result=true</i> |
| 3399 | <result> = icmp olt float 4.0, 5.0 <i>; yields: result=true</i> |
| 3400 | <result> = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i> |
| 3401 | </pre> |
| 3402 | </div> |
| 3403 | |
Reid Spencer | 2fd21e6 | 2006-11-08 01:18:52 +0000 | [diff] [blame] | 3404 | <!-- _______________________________________________________________________ --> |
| 3405 | <div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>' |
| 3406 | Instruction</a> </div> |
| 3407 | <div class="doc_text"> |
| 3408 | <h5>Syntax:</h5> |
| 3409 | <pre> <result> = phi <ty> [ <val0>, <label0>], ...<br></pre> |
| 3410 | <h5>Overview:</h5> |
| 3411 | <p>The '<tt>phi</tt>' instruction is used to implement the φ node in |
| 3412 | the SSA graph representing the function.</p> |
| 3413 | <h5>Arguments:</h5> |
| 3414 | <p>The type of the incoming values are specified with the first type |
| 3415 | field. After this, the '<tt>phi</tt>' instruction takes a list of pairs |
| 3416 | as arguments, with one pair for each predecessor basic block of the |
| 3417 | current block. Only values of <a href="#t_firstclass">first class</a> |
| 3418 | type may be used as the value arguments to the PHI node. Only labels |
| 3419 | may be used as the label arguments.</p> |
| 3420 | <p>There must be no non-phi instructions between the start of a basic |
| 3421 | block and the PHI instructions: i.e. PHI instructions must be first in |
| 3422 | a basic block.</p> |
| 3423 | <h5>Semantics:</h5> |
| 3424 | <p>At runtime, the '<tt>phi</tt>' instruction logically takes on the |
| 3425 | value specified by the parameter, depending on which basic block we |
| 3426 | came from in the last <a href="#terminators">terminator</a> instruction.</p> |
| 3427 | <h5>Example:</h5> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 3428 | <pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add i32 %indvar, 1<br> br label %Loop<br></pre> |
Reid Spencer | 2fd21e6 | 2006-11-08 01:18:52 +0000 | [diff] [blame] | 3429 | </div> |
| 3430 | |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 3431 | <!-- _______________________________________________________________________ --> |
| 3432 | <div class="doc_subsubsection"> |
| 3433 | <a name="i_select">'<tt>select</tt>' Instruction</a> |
| 3434 | </div> |
| 3435 | |
| 3436 | <div class="doc_text"> |
| 3437 | |
| 3438 | <h5>Syntax:</h5> |
| 3439 | |
| 3440 | <pre> |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 3441 | <result> = select i1 <cond>, <ty> <val1>, <ty> <val2> <i>; yields ty</i> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 3442 | </pre> |
| 3443 | |
| 3444 | <h5>Overview:</h5> |
| 3445 | |
| 3446 | <p> |
| 3447 | The '<tt>select</tt>' instruction is used to choose one value based on a |
| 3448 | condition, without branching. |
| 3449 | </p> |
| 3450 | |
| 3451 | |
| 3452 | <h5>Arguments:</h5> |
| 3453 | |
| 3454 | <p> |
| 3455 | The '<tt>select</tt>' instruction requires a boolean value indicating the condition, and two values of the same <a href="#t_firstclass">first class</a> type. |
| 3456 | </p> |
| 3457 | |
| 3458 | <h5>Semantics:</h5> |
| 3459 | |
| 3460 | <p> |
| 3461 | If the boolean condition evaluates to true, the instruction returns the first |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 3462 | value argument; otherwise, it returns the second value argument. |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 3463 | </p> |
| 3464 | |
| 3465 | <h5>Example:</h5> |
| 3466 | |
| 3467 | <pre> |
Reid Spencer | c78f337 | 2007-01-12 03:35:51 +0000 | [diff] [blame] | 3468 | %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 3469 | </pre> |
| 3470 | </div> |
| 3471 | |
Robert Bocchino | 05ccd70 | 2006-01-15 20:48:27 +0000 | [diff] [blame] | 3472 | |
| 3473 | <!-- _______________________________________________________________________ --> |
| 3474 | <div class="doc_subsubsection"> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3475 | <a name="i_call">'<tt>call</tt>' Instruction</a> |
| 3476 | </div> |
| 3477 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3478 | <div class="doc_text"> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3479 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 3480 | <h5>Syntax:</h5> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3481 | <pre> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 3482 | <result> = [tail] call [<a href="#callingconv">cconv</a>] <ty>* <fnptrval>(<param list>) |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3483 | </pre> |
| 3484 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 3485 | <h5>Overview:</h5> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3486 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3487 | <p>The '<tt>call</tt>' instruction represents a simple function call.</p> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3488 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 3489 | <h5>Arguments:</h5> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3490 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3491 | <p>This instruction requires several arguments:</p> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3492 | |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 3493 | <ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3494 | <li> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 3495 | <p>The optional "tail" marker indicates whether the callee function accesses |
| 3496 | any allocas or varargs in the caller. If the "tail" marker is present, the |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3497 | function call is eligible for tail call optimization. Note that calls may |
| 3498 | be marked "tail" even if they do not occur before a <a |
| 3499 | href="#i_ret"><tt>ret</tt></a> instruction. |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3500 | </li> |
| 3501 | <li> |
Duncan Sands | 8036ca4 | 2007-03-30 12:22:09 +0000 | [diff] [blame] | 3502 | <p>The optional "cconv" marker indicates which <a href="#callingconv">calling |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 3503 | convention</a> the call should use. If none is specified, the call defaults |
| 3504 | to using C calling conventions. |
| 3505 | </li> |
| 3506 | <li> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3507 | <p>'<tt>ty</tt>': shall be the signature of the pointer to function value |
| 3508 | being invoked. The argument types must match the types implied by this |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 3509 | signature. This type can be omitted if the function is not varargs and |
| 3510 | if the function type does not return a pointer to a function.</p> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3511 | </li> |
| 3512 | <li> |
| 3513 | <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to |
| 3514 | be invoked. In most cases, this is a direct function invocation, but |
| 3515 | indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 3516 | to function value.</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3517 | </li> |
| 3518 | <li> |
| 3519 | <p>'<tt>function args</tt>': argument list whose types match the |
Reid Spencer | a7e302a | 2005-05-01 22:22:57 +0000 | [diff] [blame] | 3520 | function signature argument types. All arguments must be of |
| 3521 | <a href="#t_firstclass">first class</a> type. If the function signature |
| 3522 | indicates the function accepts a variable number of arguments, the extra |
| 3523 | arguments can be specified.</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3524 | </li> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 3525 | </ol> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3526 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 3527 | <h5>Semantics:</h5> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3528 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3529 | <p>The '<tt>call</tt>' instruction is used to cause control flow to |
| 3530 | transfer to a specified function, with its incoming arguments bound to |
| 3531 | the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>' |
| 3532 | instruction in the called function, control flow continues with the |
| 3533 | instruction after the function call, and the return value of the |
| 3534 | function is bound to the result argument. This is a simpler case of |
| 3535 | the <a href="#i_invoke">invoke</a> instruction.</p> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3536 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 3537 | <h5>Example:</h5> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3538 | |
| 3539 | <pre> |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 3540 | %retval = call i32 %test(i32 %argc) |
| 3541 | call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42); |
| 3542 | %X = tail call i32 %foo() |
| 3543 | %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo() |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3544 | </pre> |
| 3545 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3546 | </div> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3547 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3548 | <!-- _______________________________________________________________________ --> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3549 | <div class="doc_subsubsection"> |
Chris Lattner | fb6977d | 2006-01-13 23:26:01 +0000 | [diff] [blame] | 3550 | <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3551 | </div> |
| 3552 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3553 | <div class="doc_text"> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3554 | |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 3555 | <h5>Syntax:</h5> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3556 | |
| 3557 | <pre> |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3558 | <resultval> = va_arg <va_list*> <arglist>, <argty> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3559 | </pre> |
| 3560 | |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 3561 | <h5>Overview:</h5> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3562 | |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3563 | <p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3564 | the "variable argument" area of a function call. It is used to implement the |
| 3565 | <tt>va_arg</tt> macro in C.</p> |
| 3566 | |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 3567 | <h5>Arguments:</h5> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3568 | |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3569 | <p>This instruction takes a <tt>va_list*</tt> value and the type of |
| 3570 | the argument. It returns a value of the specified argument type and |
Jeff Cohen | 25d4f7e | 2005-11-11 02:15:27 +0000 | [diff] [blame] | 3571 | increments the <tt>va_list</tt> to point to the next argument. Again, the |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3572 | actual type of <tt>va_list</tt> is target specific.</p> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3573 | |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 3574 | <h5>Semantics:</h5> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3575 | |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3576 | <p>The '<tt>va_arg</tt>' instruction loads an argument of the specified |
| 3577 | type from the specified <tt>va_list</tt> and causes the |
| 3578 | <tt>va_list</tt> to point to the next argument. For more information, |
| 3579 | see the variable argument handling <a href="#int_varargs">Intrinsic |
| 3580 | Functions</a>.</p> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3581 | |
| 3582 | <p>It is legal for this instruction to be called in a function which does not |
| 3583 | take a variable number of arguments, for example, the <tt>vfprintf</tt> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3584 | function.</p> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3585 | |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3586 | <p><tt>va_arg</tt> is an LLVM instruction instead of an <a |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 3587 | href="#intrinsics">intrinsic function</a> because it takes a type as an |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3588 | argument.</p> |
| 3589 | |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 3590 | <h5>Example:</h5> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3591 | |
| 3592 | <p>See the <a href="#int_varargs">variable argument processing</a> section.</p> |
| 3593 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3594 | </div> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3595 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3596 | <!-- *********************************************************************** --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3597 | <div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div> |
| 3598 | <!-- *********************************************************************** --> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3599 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3600 | <div class="doc_text"> |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3601 | |
| 3602 | <p>LLVM supports the notion of an "intrinsic function". These functions have |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 3603 | well known names and semantics and are required to follow certain restrictions. |
| 3604 | Overall, these intrinsics represent an extension mechanism for the LLVM |
| 3605 | language that does not require changing all of the transformations in LLVM to |
| 3606 | add to the language (or the bytecode reader/writer, the parser, |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3607 | etc...).</p> |
| 3608 | |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 3609 | <p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This |
| 3610 | prefix is reserved in LLVM for intrinsic names; thus, functions may not be named |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3611 | this. Intrinsic functions must always be external functions: you cannot define |
| 3612 | the body of intrinsic functions. Intrinsic functions may only be used in call |
| 3613 | or invoke instructions: it is illegal to take the address of an intrinsic |
| 3614 | function. Additionally, because intrinsic functions are part of the LLVM |
| 3615 | language, it is required that they all be documented here if any are added.</p> |
| 3616 | |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 3617 | <p>Some intrinsic functions can be overloaded. That is, the intrinsic represents |
| 3618 | a family of functions that perform the same operation but on different data |
| 3619 | types. This is most frequent with the integer types. Since LLVM can represent |
| 3620 | over 8 million different integer types, there is a way to declare an intrinsic |
| 3621 | that can be overloaded based on its arguments. Such intrinsics will have the |
| 3622 | names of the arbitrary types encoded into the intrinsic function name, each |
| 3623 | preceded by a period. For example, the <tt>llvm.ctpop</tt> function can take an |
| 3624 | integer of any width. This leads to a family of functions such as |
| 3625 | <tt>i32 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i32 @llvm.ctpop.i29(i29 %val)</tt>. |
| 3626 | </p> |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3627 | |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 3628 | |
| 3629 | <p>To learn how to add an intrinsic function, please see the |
| 3630 | <a href="ExtendingLLVM.html">Extending LLVM Guide</a>. |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3631 | </p> |
| 3632 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3633 | </div> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3634 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3635 | <!-- ======================================================================= --> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3636 | <div class="doc_subsection"> |
| 3637 | <a name="int_varargs">Variable Argument Handling Intrinsics</a> |
| 3638 | </div> |
| 3639 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3640 | <div class="doc_text"> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3641 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3642 | <p>Variable argument support is defined in LLVM with the <a |
Chris Lattner | fb6977d | 2006-01-13 23:26:01 +0000 | [diff] [blame] | 3643 | href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3644 | intrinsic functions. These functions are related to the similarly |
| 3645 | named macros defined in the <tt><stdarg.h></tt> header file.</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3646 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3647 | <p>All of these functions operate on arguments that use a |
| 3648 | target-specific value type "<tt>va_list</tt>". The LLVM assembly |
| 3649 | language reference manual does not define what this type is, so all |
| 3650 | transformations should be prepared to handle intrinsics with any type |
| 3651 | used.</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3652 | |
Chris Lattner | 374ab30 | 2006-05-15 17:26:46 +0000 | [diff] [blame] | 3653 | <p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3654 | instruction and the variable argument handling intrinsic functions are |
| 3655 | used.</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3656 | |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3657 | <pre> |
Anton Korobeynikov | 5d522f3 | 2007-03-21 23:58:04 +0000 | [diff] [blame] | 3658 | define i32 @test(i32 %X, ...) { |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3659 | ; Initialize variable argument processing |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 3660 | %ap = alloca i8 * |
Chris Lattner | b75137d | 2007-01-08 07:55:15 +0000 | [diff] [blame] | 3661 | %ap2 = bitcast i8** %ap to i8* |
Anton Korobeynikov | 5d522f3 | 2007-03-21 23:58:04 +0000 | [diff] [blame] | 3662 | call void @llvm.va_start(i8* %ap2) |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3663 | |
| 3664 | ; Read a single integer argument |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 3665 | %tmp = va_arg i8 ** %ap, i32 |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3666 | |
| 3667 | ; Demonstrate usage of llvm.va_copy and llvm.va_end |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 3668 | %aq = alloca i8 * |
Chris Lattner | b75137d | 2007-01-08 07:55:15 +0000 | [diff] [blame] | 3669 | %aq2 = bitcast i8** %aq to i8* |
Anton Korobeynikov | 5d522f3 | 2007-03-21 23:58:04 +0000 | [diff] [blame] | 3670 | call void @llvm.va_copy(i8 *%aq2, i8* %ap2) |
| 3671 | call void @llvm.va_end(i8* %aq2) |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3672 | |
| 3673 | ; Stop processing of arguments. |
Anton Korobeynikov | 5d522f3 | 2007-03-21 23:58:04 +0000 | [diff] [blame] | 3674 | call void @llvm.va_end(i8* %ap2) |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 3675 | ret i32 %tmp |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3676 | } |
Anton Korobeynikov | 5d522f3 | 2007-03-21 23:58:04 +0000 | [diff] [blame] | 3677 | |
| 3678 | declare void @llvm.va_start(i8*) |
| 3679 | declare void @llvm.va_copy(i8*, i8*) |
| 3680 | declare void @llvm.va_end(i8*) |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3681 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3682 | </div> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3683 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3684 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3685 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 3686 | <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3687 | </div> |
| 3688 | |
| 3689 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3690 | <div class="doc_text"> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3691 | <h5>Syntax:</h5> |
Chris Lattner | b75137d | 2007-01-08 07:55:15 +0000 | [diff] [blame] | 3692 | <pre> declare void %llvm.va_start(i8* <arglist>)<br></pre> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3693 | <h5>Overview:</h5> |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3694 | <P>The '<tt>llvm.va_start</tt>' intrinsic initializes |
| 3695 | <tt>*<arglist></tt> for subsequent use by <tt><a |
| 3696 | href="#i_va_arg">va_arg</a></tt>.</p> |
| 3697 | |
| 3698 | <h5>Arguments:</h5> |
| 3699 | |
| 3700 | <P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p> |
| 3701 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3702 | <h5>Semantics:</h5> |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3703 | |
| 3704 | <P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt> |
| 3705 | macro available in C. In a target-dependent way, it initializes the |
| 3706 | <tt>va_list</tt> element the argument points to, so that the next call to |
| 3707 | <tt>va_arg</tt> will produce the first variable argument passed to the function. |
| 3708 | Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the |
| 3709 | last argument of the function, the compiler can figure that out.</p> |
| 3710 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3711 | </div> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3712 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3713 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3714 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 3715 | <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3716 | </div> |
| 3717 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3718 | <div class="doc_text"> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3719 | <h5>Syntax:</h5> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 3720 | <pre> declare void @llvm.va_end(i8* <arglist>)<br></pre> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3721 | <h5>Overview:</h5> |
Chris Lattner | b75137d | 2007-01-08 07:55:15 +0000 | [diff] [blame] | 3722 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3723 | <p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt><arglist></tt> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 3724 | which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3725 | or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p> |
Chris Lattner | b75137d | 2007-01-08 07:55:15 +0000 | [diff] [blame] | 3726 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3727 | <h5>Arguments:</h5> |
Chris Lattner | b75137d | 2007-01-08 07:55:15 +0000 | [diff] [blame] | 3728 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3729 | <p>The argument is a <tt>va_list</tt> to destroy.</p> |
Chris Lattner | b75137d | 2007-01-08 07:55:15 +0000 | [diff] [blame] | 3730 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3731 | <h5>Semantics:</h5> |
Chris Lattner | b75137d | 2007-01-08 07:55:15 +0000 | [diff] [blame] | 3732 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3733 | <p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3734 | macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>. |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 3735 | Calls to <a href="#int_va_start"><tt>llvm.va_start</tt></a> and <a |
| 3736 | href="#int_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3737 | with calls to <tt>llvm.va_end</tt>.</p> |
Chris Lattner | b75137d | 2007-01-08 07:55:15 +0000 | [diff] [blame] | 3738 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3739 | </div> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3740 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3741 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3742 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 3743 | <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3744 | </div> |
| 3745 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3746 | <div class="doc_text"> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3747 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3748 | <h5>Syntax:</h5> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3749 | |
| 3750 | <pre> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 3751 | declare void @llvm.va_copy(i8* <destarglist>, i8* <srcarglist>) |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3752 | </pre> |
| 3753 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3754 | <h5>Overview:</h5> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3755 | |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3756 | <p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from |
| 3757 | the source argument list to the destination argument list.</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3758 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3759 | <h5>Arguments:</h5> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3760 | |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3761 | <p>The first argument is a pointer to a <tt>va_list</tt> element to initialize. |
Andrew Lenharth | d0a4c62 | 2005-06-22 20:38:11 +0000 | [diff] [blame] | 3762 | The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p> |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3763 | |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3764 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3765 | <h5>Semantics:</h5> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3766 | |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3767 | <p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro |
| 3768 | available in C. In a target-dependent way, it copies the source |
| 3769 | <tt>va_list</tt> element into the destination list. This intrinsic is necessary |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 3770 | because the <tt><a href="#int_va_start">llvm.va_start</a></tt> intrinsic may be |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3771 | arbitrarily complex and require memory allocation, for example.</p> |
| 3772 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3773 | </div> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3774 | |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3775 | <!-- ======================================================================= --> |
| 3776 | <div class="doc_subsection"> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3777 | <a name="int_gc">Accurate Garbage Collection Intrinsics</a> |
| 3778 | </div> |
| 3779 | |
| 3780 | <div class="doc_text"> |
| 3781 | |
| 3782 | <p> |
| 3783 | LLVM support for <a href="GarbageCollection.html">Accurate Garbage |
| 3784 | Collection</a> requires the implementation and generation of these intrinsics. |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 3785 | These intrinsics allow identification of <a href="#int_gcroot">GC roots on the |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3786 | stack</a>, as well as garbage collector implementations that require <a |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 3787 | href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers. |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3788 | Front-ends for type-safe garbage collected languages should generate these |
| 3789 | intrinsics to make use of the LLVM garbage collectors. For more details, see <a |
| 3790 | href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>. |
| 3791 | </p> |
| 3792 | </div> |
| 3793 | |
| 3794 | <!-- _______________________________________________________________________ --> |
| 3795 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 3796 | <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3797 | </div> |
| 3798 | |
| 3799 | <div class="doc_text"> |
| 3800 | |
| 3801 | <h5>Syntax:</h5> |
| 3802 | |
| 3803 | <pre> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 3804 | declare void @llvm.gcroot(<ty>** %ptrloc, <ty2>* %metadata) |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3805 | </pre> |
| 3806 | |
| 3807 | <h5>Overview:</h5> |
| 3808 | |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 3809 | <p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3810 | the code generator, and allows some metadata to be associated with it.</p> |
| 3811 | |
| 3812 | <h5>Arguments:</h5> |
| 3813 | |
| 3814 | <p>The first argument specifies the address of a stack object that contains the |
| 3815 | root pointer. The second pointer (which must be either a constant or a global |
| 3816 | value address) contains the meta-data to be associated with the root.</p> |
| 3817 | |
| 3818 | <h5>Semantics:</h5> |
| 3819 | |
| 3820 | <p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc" |
| 3821 | location. At compile-time, the code generator generates information to allow |
| 3822 | the runtime to find the pointer at GC safe points. |
| 3823 | </p> |
| 3824 | |
| 3825 | </div> |
| 3826 | |
| 3827 | |
| 3828 | <!-- _______________________________________________________________________ --> |
| 3829 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 3830 | <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3831 | </div> |
| 3832 | |
| 3833 | <div class="doc_text"> |
| 3834 | |
| 3835 | <h5>Syntax:</h5> |
| 3836 | |
| 3837 | <pre> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 3838 | declare i8 * @llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr) |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3839 | </pre> |
| 3840 | |
| 3841 | <h5>Overview:</h5> |
| 3842 | |
| 3843 | <p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap |
| 3844 | locations, allowing garbage collector implementations that require read |
| 3845 | barriers.</p> |
| 3846 | |
| 3847 | <h5>Arguments:</h5> |
| 3848 | |
Chris Lattner | 80626e9 | 2006-03-14 20:02:51 +0000 | [diff] [blame] | 3849 | <p>The second argument is the address to read from, which should be an address |
| 3850 | allocated from the garbage collector. The first object is a pointer to the |
| 3851 | start of the referenced object, if needed by the language runtime (otherwise |
| 3852 | null).</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3853 | |
| 3854 | <h5>Semantics:</h5> |
| 3855 | |
| 3856 | <p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load |
| 3857 | instruction, but may be replaced with substantially more complex code by the |
| 3858 | garbage collector runtime, as needed.</p> |
| 3859 | |
| 3860 | </div> |
| 3861 | |
| 3862 | |
| 3863 | <!-- _______________________________________________________________________ --> |
| 3864 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 3865 | <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3866 | </div> |
| 3867 | |
| 3868 | <div class="doc_text"> |
| 3869 | |
| 3870 | <h5>Syntax:</h5> |
| 3871 | |
| 3872 | <pre> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 3873 | declare void @llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2) |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3874 | </pre> |
| 3875 | |
| 3876 | <h5>Overview:</h5> |
| 3877 | |
| 3878 | <p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap |
| 3879 | locations, allowing garbage collector implementations that require write |
| 3880 | barriers (such as generational or reference counting collectors).</p> |
| 3881 | |
| 3882 | <h5>Arguments:</h5> |
| 3883 | |
Chris Lattner | 80626e9 | 2006-03-14 20:02:51 +0000 | [diff] [blame] | 3884 | <p>The first argument is the reference to store, the second is the start of the |
| 3885 | object to store it to, and the third is the address of the field of Obj to |
| 3886 | store to. If the runtime does not require a pointer to the object, Obj may be |
| 3887 | null.</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3888 | |
| 3889 | <h5>Semantics:</h5> |
| 3890 | |
| 3891 | <p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store |
| 3892 | instruction, but may be replaced with substantially more complex code by the |
| 3893 | garbage collector runtime, as needed.</p> |
| 3894 | |
| 3895 | </div> |
| 3896 | |
| 3897 | |
| 3898 | |
| 3899 | <!-- ======================================================================= --> |
| 3900 | <div class="doc_subsection"> |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 3901 | <a name="int_codegen">Code Generator Intrinsics</a> |
| 3902 | </div> |
| 3903 | |
| 3904 | <div class="doc_text"> |
| 3905 | <p> |
| 3906 | These intrinsics are provided by LLVM to expose special features that may only |
| 3907 | be implemented with code generator support. |
| 3908 | </p> |
| 3909 | |
| 3910 | </div> |
| 3911 | |
| 3912 | <!-- _______________________________________________________________________ --> |
| 3913 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 3914 | <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a> |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 3915 | </div> |
| 3916 | |
| 3917 | <div class="doc_text"> |
| 3918 | |
| 3919 | <h5>Syntax:</h5> |
| 3920 | <pre> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 3921 | declare i8 *@llvm.returnaddress(i32 <level>) |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 3922 | </pre> |
| 3923 | |
| 3924 | <h5>Overview:</h5> |
| 3925 | |
| 3926 | <p> |
Chris Lattner | 32b5d71 | 2006-10-15 20:05:59 +0000 | [diff] [blame] | 3927 | The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a |
| 3928 | target-specific value indicating the return address of the current function |
| 3929 | or one of its callers. |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 3930 | </p> |
| 3931 | |
| 3932 | <h5>Arguments:</h5> |
| 3933 | |
| 3934 | <p> |
| 3935 | The argument to this intrinsic indicates which function to return the address |
| 3936 | for. Zero indicates the calling function, one indicates its caller, etc. The |
| 3937 | argument is <b>required</b> to be a constant integer value. |
| 3938 | </p> |
| 3939 | |
| 3940 | <h5>Semantics:</h5> |
| 3941 | |
| 3942 | <p> |
| 3943 | The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating |
| 3944 | the return address of the specified call frame, or zero if it cannot be |
| 3945 | identified. The value returned by this intrinsic is likely to be incorrect or 0 |
| 3946 | for arguments other than zero, so it should only be used for debugging purposes. |
| 3947 | </p> |
| 3948 | |
| 3949 | <p> |
| 3950 | Note that calling this intrinsic does not prevent function inlining or other |
Chris Lattner | b40bb38 | 2005-03-07 20:30:51 +0000 | [diff] [blame] | 3951 | aggressive transformations, so the value returned may not be that of the obvious |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 3952 | source-language caller. |
| 3953 | </p> |
| 3954 | </div> |
| 3955 | |
| 3956 | |
| 3957 | <!-- _______________________________________________________________________ --> |
| 3958 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 3959 | <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a> |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 3960 | </div> |
| 3961 | |
| 3962 | <div class="doc_text"> |
| 3963 | |
| 3964 | <h5>Syntax:</h5> |
| 3965 | <pre> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 3966 | declare i8 *@llvm.frameaddress(i32 <level>) |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 3967 | </pre> |
| 3968 | |
| 3969 | <h5>Overview:</h5> |
| 3970 | |
| 3971 | <p> |
Chris Lattner | 32b5d71 | 2006-10-15 20:05:59 +0000 | [diff] [blame] | 3972 | The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the |
| 3973 | target-specific frame pointer value for the specified stack frame. |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 3974 | </p> |
| 3975 | |
| 3976 | <h5>Arguments:</h5> |
| 3977 | |
| 3978 | <p> |
| 3979 | The argument to this intrinsic indicates which function to return the frame |
| 3980 | pointer for. Zero indicates the calling function, one indicates its caller, |
| 3981 | etc. The argument is <b>required</b> to be a constant integer value. |
| 3982 | </p> |
| 3983 | |
| 3984 | <h5>Semantics:</h5> |
| 3985 | |
| 3986 | <p> |
| 3987 | The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating |
| 3988 | the frame address of the specified call frame, or zero if it cannot be |
| 3989 | identified. The value returned by this intrinsic is likely to be incorrect or 0 |
| 3990 | for arguments other than zero, so it should only be used for debugging purposes. |
| 3991 | </p> |
| 3992 | |
| 3993 | <p> |
| 3994 | Note that calling this intrinsic does not prevent function inlining or other |
Chris Lattner | b40bb38 | 2005-03-07 20:30:51 +0000 | [diff] [blame] | 3995 | aggressive transformations, so the value returned may not be that of the obvious |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 3996 | source-language caller. |
| 3997 | </p> |
| 3998 | </div> |
| 3999 | |
Chris Lattner | 9a9d7ac | 2005-02-28 19:24:19 +0000 | [diff] [blame] | 4000 | <!-- _______________________________________________________________________ --> |
| 4001 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4002 | <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a> |
Chris Lattner | 57e1f39 | 2006-01-13 02:03:13 +0000 | [diff] [blame] | 4003 | </div> |
| 4004 | |
| 4005 | <div class="doc_text"> |
| 4006 | |
| 4007 | <h5>Syntax:</h5> |
| 4008 | <pre> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 4009 | declare i8 *@llvm.stacksave() |
Chris Lattner | 57e1f39 | 2006-01-13 02:03:13 +0000 | [diff] [blame] | 4010 | </pre> |
| 4011 | |
| 4012 | <h5>Overview:</h5> |
| 4013 | |
| 4014 | <p> |
| 4015 | The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4016 | the function stack, for use with <a href="#int_stackrestore"> |
Chris Lattner | 57e1f39 | 2006-01-13 02:03:13 +0000 | [diff] [blame] | 4017 | <tt>llvm.stackrestore</tt></a>. This is useful for implementing language |
| 4018 | features like scoped automatic variable sized arrays in C99. |
| 4019 | </p> |
| 4020 | |
| 4021 | <h5>Semantics:</h5> |
| 4022 | |
| 4023 | <p> |
| 4024 | This intrinsic returns a opaque pointer value that can be passed to <a |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4025 | href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an |
Chris Lattner | 57e1f39 | 2006-01-13 02:03:13 +0000 | [diff] [blame] | 4026 | <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from |
| 4027 | <tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the |
| 4028 | state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In |
| 4029 | practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack |
| 4030 | that were allocated after the <tt>llvm.stacksave</tt> was executed. |
| 4031 | </p> |
| 4032 | |
| 4033 | </div> |
| 4034 | |
| 4035 | <!-- _______________________________________________________________________ --> |
| 4036 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4037 | <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a> |
Chris Lattner | 57e1f39 | 2006-01-13 02:03:13 +0000 | [diff] [blame] | 4038 | </div> |
| 4039 | |
| 4040 | <div class="doc_text"> |
| 4041 | |
| 4042 | <h5>Syntax:</h5> |
| 4043 | <pre> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 4044 | declare void @llvm.stackrestore(i8 * %ptr) |
Chris Lattner | 57e1f39 | 2006-01-13 02:03:13 +0000 | [diff] [blame] | 4045 | </pre> |
| 4046 | |
| 4047 | <h5>Overview:</h5> |
| 4048 | |
| 4049 | <p> |
| 4050 | The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of |
| 4051 | the function stack to the state it was in when the corresponding <a |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4052 | href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is |
Chris Lattner | 57e1f39 | 2006-01-13 02:03:13 +0000 | [diff] [blame] | 4053 | useful for implementing language features like scoped automatic variable sized |
| 4054 | arrays in C99. |
| 4055 | </p> |
| 4056 | |
| 4057 | <h5>Semantics:</h5> |
| 4058 | |
| 4059 | <p> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4060 | See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>. |
Chris Lattner | 57e1f39 | 2006-01-13 02:03:13 +0000 | [diff] [blame] | 4061 | </p> |
| 4062 | |
| 4063 | </div> |
| 4064 | |
| 4065 | |
| 4066 | <!-- _______________________________________________________________________ --> |
| 4067 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4068 | <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a> |
Chris Lattner | 9a9d7ac | 2005-02-28 19:24:19 +0000 | [diff] [blame] | 4069 | </div> |
| 4070 | |
| 4071 | <div class="doc_text"> |
| 4072 | |
| 4073 | <h5>Syntax:</h5> |
| 4074 | <pre> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 4075 | declare void @llvm.prefetch(i8 * <address>, |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 4076 | i32 <rw>, i32 <locality>) |
Chris Lattner | 9a9d7ac | 2005-02-28 19:24:19 +0000 | [diff] [blame] | 4077 | </pre> |
| 4078 | |
| 4079 | <h5>Overview:</h5> |
| 4080 | |
| 4081 | |
| 4082 | <p> |
| 4083 | The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 4084 | a prefetch instruction if supported; otherwise, it is a noop. Prefetches have |
| 4085 | no |
| 4086 | effect on the behavior of the program but can change its performance |
Chris Lattner | 2a61536 | 2005-02-28 19:47:14 +0000 | [diff] [blame] | 4087 | characteristics. |
Chris Lattner | 9a9d7ac | 2005-02-28 19:24:19 +0000 | [diff] [blame] | 4088 | </p> |
| 4089 | |
| 4090 | <h5>Arguments:</h5> |
| 4091 | |
| 4092 | <p> |
| 4093 | <tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier |
| 4094 | determining if the fetch should be for a read (0) or write (1), and |
| 4095 | <tt>locality</tt> is a temporal locality specifier ranging from (0) - no |
Chris Lattner | aeffb4a | 2005-03-07 20:31:38 +0000 | [diff] [blame] | 4096 | locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and |
Chris Lattner | 9a9d7ac | 2005-02-28 19:24:19 +0000 | [diff] [blame] | 4097 | <tt>locality</tt> arguments must be constant integers. |
| 4098 | </p> |
| 4099 | |
| 4100 | <h5>Semantics:</h5> |
| 4101 | |
| 4102 | <p> |
| 4103 | This intrinsic does not modify the behavior of the program. In particular, |
| 4104 | prefetches cannot trap and do not produce a value. On targets that support this |
| 4105 | intrinsic, the prefetch can provide hints to the processor cache for better |
| 4106 | performance. |
| 4107 | </p> |
| 4108 | |
| 4109 | </div> |
| 4110 | |
Andrew Lenharth | 7f4ec3b | 2005-03-28 20:05:49 +0000 | [diff] [blame] | 4111 | <!-- _______________________________________________________________________ --> |
| 4112 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4113 | <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a> |
Andrew Lenharth | 7f4ec3b | 2005-03-28 20:05:49 +0000 | [diff] [blame] | 4114 | </div> |
| 4115 | |
| 4116 | <div class="doc_text"> |
| 4117 | |
| 4118 | <h5>Syntax:</h5> |
| 4119 | <pre> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 4120 | declare void @llvm.pcmarker( i32 <id> ) |
Andrew Lenharth | 7f4ec3b | 2005-03-28 20:05:49 +0000 | [diff] [blame] | 4121 | </pre> |
| 4122 | |
| 4123 | <h5>Overview:</h5> |
| 4124 | |
| 4125 | |
| 4126 | <p> |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 4127 | The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter |
| 4128 | (PC) in a region of |
Andrew Lenharth | 7f4ec3b | 2005-03-28 20:05:49 +0000 | [diff] [blame] | 4129 | code to simulators and other tools. The method is target specific, but it is |
| 4130 | expected that the marker will use exported symbols to transmit the PC of the marker. |
Jeff Cohen | 25d4f7e | 2005-11-11 02:15:27 +0000 | [diff] [blame] | 4131 | The marker makes no guarantees that it will remain with any specific instruction |
Chris Lattner | d07c3f4 | 2005-11-15 06:07:55 +0000 | [diff] [blame] | 4132 | after optimizations. It is possible that the presence of a marker will inhibit |
Chris Lattner | b3e7afd | 2006-03-24 07:16:10 +0000 | [diff] [blame] | 4133 | optimizations. The intended use is to be inserted after optimizations to allow |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 4134 | correlations of simulation runs. |
Andrew Lenharth | 7f4ec3b | 2005-03-28 20:05:49 +0000 | [diff] [blame] | 4135 | </p> |
| 4136 | |
| 4137 | <h5>Arguments:</h5> |
| 4138 | |
| 4139 | <p> |
| 4140 | <tt>id</tt> is a numerical id identifying the marker. |
| 4141 | </p> |
| 4142 | |
| 4143 | <h5>Semantics:</h5> |
| 4144 | |
| 4145 | <p> |
| 4146 | This intrinsic does not modify the behavior of the program. Backends that do not |
| 4147 | support this intrinisic may ignore it. |
| 4148 | </p> |
| 4149 | |
| 4150 | </div> |
| 4151 | |
Andrew Lenharth | 51b8d54 | 2005-11-11 16:47:30 +0000 | [diff] [blame] | 4152 | <!-- _______________________________________________________________________ --> |
| 4153 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4154 | <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a> |
Andrew Lenharth | 51b8d54 | 2005-11-11 16:47:30 +0000 | [diff] [blame] | 4155 | </div> |
| 4156 | |
| 4157 | <div class="doc_text"> |
| 4158 | |
| 4159 | <h5>Syntax:</h5> |
| 4160 | <pre> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 4161 | declare i64 @llvm.readcyclecounter( ) |
Andrew Lenharth | 51b8d54 | 2005-11-11 16:47:30 +0000 | [diff] [blame] | 4162 | </pre> |
| 4163 | |
| 4164 | <h5>Overview:</h5> |
| 4165 | |
| 4166 | |
| 4167 | <p> |
| 4168 | The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle |
| 4169 | counter register (or similar low latency, high accuracy clocks) on those targets |
| 4170 | that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC. |
| 4171 | As the backing counters overflow quickly (on the order of 9 seconds on alpha), this |
| 4172 | should only be used for small timings. |
| 4173 | </p> |
| 4174 | |
| 4175 | <h5>Semantics:</h5> |
| 4176 | |
| 4177 | <p> |
| 4178 | When directly supported, reading the cycle counter should not modify any memory. |
| 4179 | Implementations are allowed to either return a application specific value or a |
| 4180 | system wide value. On backends without support, this is lowered to a constant 0. |
| 4181 | </p> |
| 4182 | |
| 4183 | </div> |
| 4184 | |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4185 | <!-- ======================================================================= --> |
| 4186 | <div class="doc_subsection"> |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4187 | <a name="int_libc">Standard C Library Intrinsics</a> |
| 4188 | </div> |
| 4189 | |
| 4190 | <div class="doc_text"> |
| 4191 | <p> |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4192 | LLVM provides intrinsics for a few important standard C library functions. |
| 4193 | These intrinsics allow source-language front-ends to pass information about the |
| 4194 | alignment of the pointer arguments to the code generator, providing opportunity |
| 4195 | for more efficient code generation. |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4196 | </p> |
| 4197 | |
| 4198 | </div> |
| 4199 | |
| 4200 | <!-- _______________________________________________________________________ --> |
| 4201 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4202 | <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a> |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4203 | </div> |
| 4204 | |
| 4205 | <div class="doc_text"> |
| 4206 | |
| 4207 | <h5>Syntax:</h5> |
| 4208 | <pre> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 4209 | declare void @llvm.memcpy.i32(i8 * <dest>, i8 * <src>, |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 4210 | i32 <len>, i32 <align>) |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 4211 | declare void @llvm.memcpy.i64(i8 * <dest>, i8 * <src>, |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 4212 | i64 <len>, i32 <align>) |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4213 | </pre> |
| 4214 | |
| 4215 | <h5>Overview:</h5> |
| 4216 | |
| 4217 | <p> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4218 | The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4219 | location to the destination location. |
| 4220 | </p> |
| 4221 | |
| 4222 | <p> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4223 | Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt> |
| 4224 | intrinsics do not return a value, and takes an extra alignment argument. |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4225 | </p> |
| 4226 | |
| 4227 | <h5>Arguments:</h5> |
| 4228 | |
| 4229 | <p> |
| 4230 | The first argument is a pointer to the destination, the second is a pointer to |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4231 | the source. The third argument is an integer argument |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4232 | specifying the number of bytes to copy, and the fourth argument is the alignment |
| 4233 | of the source and destination locations. |
| 4234 | </p> |
| 4235 | |
Chris Lattner | 3301ced | 2004-02-12 21:18:15 +0000 | [diff] [blame] | 4236 | <p> |
| 4237 | If the call to this intrinisic has an alignment value that is not 0 or 1, then |
Chris Lattner | f0afc2c | 2006-03-04 00:02:10 +0000 | [diff] [blame] | 4238 | the caller guarantees that both the source and destination pointers are aligned |
| 4239 | to that boundary. |
Chris Lattner | 3301ced | 2004-02-12 21:18:15 +0000 | [diff] [blame] | 4240 | </p> |
| 4241 | |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4242 | <h5>Semantics:</h5> |
| 4243 | |
| 4244 | <p> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4245 | The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4246 | location to the destination location, which are not allowed to overlap. It |
| 4247 | copies "len" bytes of memory over. If the argument is known to be aligned to |
| 4248 | some boundary, this can be specified as the fourth argument, otherwise it should |
| 4249 | be set to 0 or 1. |
| 4250 | </p> |
| 4251 | </div> |
| 4252 | |
| 4253 | |
Chris Lattner | 0eb51b4 | 2004-02-12 18:10:10 +0000 | [diff] [blame] | 4254 | <!-- _______________________________________________________________________ --> |
| 4255 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4256 | <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a> |
Chris Lattner | 0eb51b4 | 2004-02-12 18:10:10 +0000 | [diff] [blame] | 4257 | </div> |
| 4258 | |
| 4259 | <div class="doc_text"> |
| 4260 | |
| 4261 | <h5>Syntax:</h5> |
| 4262 | <pre> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 4263 | declare void @llvm.memmove.i32(i8 * <dest>, i8 * <src>, |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 4264 | i32 <len>, i32 <align>) |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 4265 | declare void @llvm.memmove.i64(i8 * <dest>, i8 * <src>, |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 4266 | i64 <len>, i32 <align>) |
Chris Lattner | 0eb51b4 | 2004-02-12 18:10:10 +0000 | [diff] [blame] | 4267 | </pre> |
| 4268 | |
| 4269 | <h5>Overview:</h5> |
| 4270 | |
| 4271 | <p> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4272 | The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source |
| 4273 | location to the destination location. It is similar to the |
| 4274 | '<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap. |
Chris Lattner | 0eb51b4 | 2004-02-12 18:10:10 +0000 | [diff] [blame] | 4275 | </p> |
| 4276 | |
| 4277 | <p> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4278 | Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt> |
| 4279 | intrinsics do not return a value, and takes an extra alignment argument. |
Chris Lattner | 0eb51b4 | 2004-02-12 18:10:10 +0000 | [diff] [blame] | 4280 | </p> |
| 4281 | |
| 4282 | <h5>Arguments:</h5> |
| 4283 | |
| 4284 | <p> |
| 4285 | The first argument is a pointer to the destination, the second is a pointer to |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4286 | the source. The third argument is an integer argument |
Chris Lattner | 0eb51b4 | 2004-02-12 18:10:10 +0000 | [diff] [blame] | 4287 | specifying the number of bytes to copy, and the fourth argument is the alignment |
| 4288 | of the source and destination locations. |
| 4289 | </p> |
| 4290 | |
Chris Lattner | 3301ced | 2004-02-12 21:18:15 +0000 | [diff] [blame] | 4291 | <p> |
| 4292 | If the call to this intrinisic has an alignment value that is not 0 or 1, then |
Chris Lattner | f0afc2c | 2006-03-04 00:02:10 +0000 | [diff] [blame] | 4293 | the caller guarantees that the source and destination pointers are aligned to |
| 4294 | that boundary. |
Chris Lattner | 3301ced | 2004-02-12 21:18:15 +0000 | [diff] [blame] | 4295 | </p> |
| 4296 | |
Chris Lattner | 0eb51b4 | 2004-02-12 18:10:10 +0000 | [diff] [blame] | 4297 | <h5>Semantics:</h5> |
| 4298 | |
| 4299 | <p> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4300 | The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source |
Chris Lattner | 0eb51b4 | 2004-02-12 18:10:10 +0000 | [diff] [blame] | 4301 | location to the destination location, which may overlap. It |
| 4302 | copies "len" bytes of memory over. If the argument is known to be aligned to |
| 4303 | some boundary, this can be specified as the fourth argument, otherwise it should |
| 4304 | be set to 0 or 1. |
| 4305 | </p> |
| 4306 | </div> |
| 4307 | |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 4308 | |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4309 | <!-- _______________________________________________________________________ --> |
| 4310 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4311 | <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a> |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4312 | </div> |
| 4313 | |
| 4314 | <div class="doc_text"> |
| 4315 | |
| 4316 | <h5>Syntax:</h5> |
| 4317 | <pre> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 4318 | declare void @llvm.memset.i32(i8 * <dest>, i8 <val>, |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 4319 | i32 <len>, i32 <align>) |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 4320 | declare void @llvm.memset.i64(i8 * <dest>, i8 <val>, |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 4321 | i64 <len>, i32 <align>) |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4322 | </pre> |
| 4323 | |
| 4324 | <h5>Overview:</h5> |
| 4325 | |
| 4326 | <p> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4327 | The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4328 | byte value. |
| 4329 | </p> |
| 4330 | |
| 4331 | <p> |
| 4332 | Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic |
| 4333 | does not return a value, and takes an extra alignment argument. |
| 4334 | </p> |
| 4335 | |
| 4336 | <h5>Arguments:</h5> |
| 4337 | |
| 4338 | <p> |
| 4339 | The first argument is a pointer to the destination to fill, the second is the |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4340 | byte value to fill it with, the third argument is an integer |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4341 | argument specifying the number of bytes to fill, and the fourth argument is the |
| 4342 | known alignment of destination location. |
| 4343 | </p> |
| 4344 | |
| 4345 | <p> |
| 4346 | If the call to this intrinisic has an alignment value that is not 0 or 1, then |
Chris Lattner | f0afc2c | 2006-03-04 00:02:10 +0000 | [diff] [blame] | 4347 | the caller guarantees that the destination pointer is aligned to that boundary. |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4348 | </p> |
| 4349 | |
| 4350 | <h5>Semantics:</h5> |
| 4351 | |
| 4352 | <p> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4353 | The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at |
| 4354 | the |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4355 | destination location. If the argument is known to be aligned to some boundary, |
| 4356 | this can be specified as the fourth argument, otherwise it should be set to 0 or |
| 4357 | 1. |
| 4358 | </p> |
| 4359 | </div> |
| 4360 | |
| 4361 | |
Chris Lattner | 3200628 | 2004-06-11 02:28:03 +0000 | [diff] [blame] | 4362 | <!-- _______________________________________________________________________ --> |
| 4363 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4364 | <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a> |
Chris Lattner | a4d7414 | 2005-07-21 01:29:16 +0000 | [diff] [blame] | 4365 | </div> |
| 4366 | |
| 4367 | <div class="doc_text"> |
| 4368 | |
| 4369 | <h5>Syntax:</h5> |
| 4370 | <pre> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 4371 | declare float @llvm.sqrt.f32(float %Val) |
| 4372 | declare double @llvm.sqrt.f64(double %Val) |
Chris Lattner | a4d7414 | 2005-07-21 01:29:16 +0000 | [diff] [blame] | 4373 | </pre> |
| 4374 | |
| 4375 | <h5>Overview:</h5> |
| 4376 | |
| 4377 | <p> |
Reid Spencer | 0b11820 | 2006-01-16 21:12:35 +0000 | [diff] [blame] | 4378 | The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand, |
Chris Lattner | a4d7414 | 2005-07-21 01:29:16 +0000 | [diff] [blame] | 4379 | returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike |
| 4380 | <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for |
| 4381 | negative numbers (which allows for better optimization). |
| 4382 | </p> |
| 4383 | |
| 4384 | <h5>Arguments:</h5> |
| 4385 | |
| 4386 | <p> |
| 4387 | The argument and return value are floating point numbers of the same type. |
| 4388 | </p> |
| 4389 | |
| 4390 | <h5>Semantics:</h5> |
| 4391 | |
| 4392 | <p> |
| 4393 | This function returns the sqrt of the specified operand if it is a positive |
| 4394 | floating point number. |
| 4395 | </p> |
| 4396 | </div> |
| 4397 | |
Chris Lattner | f4d252d | 2006-09-08 06:34:02 +0000 | [diff] [blame] | 4398 | <!-- _______________________________________________________________________ --> |
| 4399 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4400 | <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a> |
Chris Lattner | f4d252d | 2006-09-08 06:34:02 +0000 | [diff] [blame] | 4401 | </div> |
| 4402 | |
| 4403 | <div class="doc_text"> |
| 4404 | |
| 4405 | <h5>Syntax:</h5> |
| 4406 | <pre> |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 4407 | declare float @llvm.powi.f32(float %Val, i32 %power) |
| 4408 | declare double @llvm.powi.f64(double %Val, i32 %power) |
Chris Lattner | f4d252d | 2006-09-08 06:34:02 +0000 | [diff] [blame] | 4409 | </pre> |
| 4410 | |
| 4411 | <h5>Overview:</h5> |
| 4412 | |
| 4413 | <p> |
| 4414 | The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the |
| 4415 | specified (positive or negative) power. The order of evaluation of |
| 4416 | multiplications is not defined. |
| 4417 | </p> |
| 4418 | |
| 4419 | <h5>Arguments:</h5> |
| 4420 | |
| 4421 | <p> |
| 4422 | The second argument is an integer power, and the first is a value to raise to |
| 4423 | that power. |
| 4424 | </p> |
| 4425 | |
| 4426 | <h5>Semantics:</h5> |
| 4427 | |
| 4428 | <p> |
| 4429 | This function returns the first value raised to the second power with an |
| 4430 | unspecified sequence of rounding operations.</p> |
| 4431 | </div> |
| 4432 | |
| 4433 | |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4434 | <!-- ======================================================================= --> |
| 4435 | <div class="doc_subsection"> |
Nate Begeman | 7e36c47 | 2006-01-13 23:26:38 +0000 | [diff] [blame] | 4436 | <a name="int_manip">Bit Manipulation Intrinsics</a> |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4437 | </div> |
| 4438 | |
| 4439 | <div class="doc_text"> |
| 4440 | <p> |
Nate Begeman | 7e36c47 | 2006-01-13 23:26:38 +0000 | [diff] [blame] | 4441 | LLVM provides intrinsics for a few important bit manipulation operations. |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4442 | These allow efficient code generation for some algorithms. |
| 4443 | </p> |
| 4444 | |
| 4445 | </div> |
| 4446 | |
| 4447 | <!-- _______________________________________________________________________ --> |
| 4448 | <div class="doc_subsubsection"> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4449 | <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a> |
Nate Begeman | 7e36c47 | 2006-01-13 23:26:38 +0000 | [diff] [blame] | 4450 | </div> |
| 4451 | |
| 4452 | <div class="doc_text"> |
| 4453 | |
| 4454 | <h5>Syntax:</h5> |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 4455 | <p>This is an overloaded intrinsic function. You can use bswap on any integer |
| 4456 | type that is an even number of bytes (i.e. BitWidth % 16 == 0). Note the suffix |
| 4457 | that includes the type for the result and the operand. |
Nate Begeman | 7e36c47 | 2006-01-13 23:26:38 +0000 | [diff] [blame] | 4458 | <pre> |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 4459 | declare i16 @llvm.bswap.i16.i16(i16 <id>) |
| 4460 | declare i32 @llvm.bswap.i32.i32(i32 <id>) |
Reid Spencer | 543ab1d | 2007-04-02 00:19:52 +0000 | [diff] [blame] | 4461 | declare i64 @llvm.bswap.i64.i64(i64 <id>) |
Nate Begeman | 7e36c47 | 2006-01-13 23:26:38 +0000 | [diff] [blame] | 4462 | </pre> |
| 4463 | |
| 4464 | <h5>Overview:</h5> |
| 4465 | |
| 4466 | <p> |
Reid Spencer | 338ea09 | 2007-04-02 02:25:19 +0000 | [diff] [blame] | 4467 | The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 4468 | values with an even number of bytes (positive multiple of 16 bits). These are |
| 4469 | useful for performing operations on data that is not in the target's native |
| 4470 | byte order. |
Nate Begeman | 7e36c47 | 2006-01-13 23:26:38 +0000 | [diff] [blame] | 4471 | </p> |
| 4472 | |
| 4473 | <h5>Semantics:</h5> |
| 4474 | |
| 4475 | <p> |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 4476 | The <tt>llvm.bswap.16.i16</tt> intrinsic returns an i16 value that has the high |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 4477 | and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt> |
| 4478 | intrinsic returns an i32 value that has the four bytes of the input i32 |
| 4479 | swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 4480 | i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48.i48</tt>, |
| 4481 | <tt>llvm.bswap.i64.i64</tt> and other intrinsics extend this concept to |
| 4482 | additional even-byte lengths (6 bytes, 8 bytes and more, respectively). |
Nate Begeman | 7e36c47 | 2006-01-13 23:26:38 +0000 | [diff] [blame] | 4483 | </p> |
| 4484 | |
| 4485 | </div> |
| 4486 | |
| 4487 | <!-- _______________________________________________________________________ --> |
| 4488 | <div class="doc_subsubsection"> |
Reid Spencer | 0b11820 | 2006-01-16 21:12:35 +0000 | [diff] [blame] | 4489 | <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a> |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4490 | </div> |
| 4491 | |
| 4492 | <div class="doc_text"> |
| 4493 | |
| 4494 | <h5>Syntax:</h5> |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 4495 | <p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit |
| 4496 | width. Not all targets support all bit widths however. |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4497 | <pre> |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 4498 | declare i32 @llvm.ctpop.i8 (i8 <src>) |
| 4499 | declare i32 @llvm.ctpop.i16(i16 <src>) |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 4500 | declare i32 @llvm.ctpop.i32(i32 <src>) |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 4501 | declare i32 @llvm.ctpop.i64(i64 <src>) |
| 4502 | declare i32 @llvm.ctpop.i256(i256 <src>) |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4503 | </pre> |
| 4504 | |
| 4505 | <h5>Overview:</h5> |
| 4506 | |
| 4507 | <p> |
Chris Lattner | ec6cb61 | 2006-01-16 22:38:59 +0000 | [diff] [blame] | 4508 | The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a |
| 4509 | value. |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4510 | </p> |
| 4511 | |
| 4512 | <h5>Arguments:</h5> |
| 4513 | |
| 4514 | <p> |
Chris Lattner | cfe6b37 | 2005-05-07 01:46:40 +0000 | [diff] [blame] | 4515 | The only argument is the value to be counted. The argument may be of any |
Reid Spencer | a517338 | 2007-01-04 16:43:23 +0000 | [diff] [blame] | 4516 | integer type. The return type must match the argument type. |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4517 | </p> |
| 4518 | |
| 4519 | <h5>Semantics:</h5> |
| 4520 | |
| 4521 | <p> |
| 4522 | The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable. |
| 4523 | </p> |
| 4524 | </div> |
| 4525 | |
| 4526 | <!-- _______________________________________________________________________ --> |
| 4527 | <div class="doc_subsubsection"> |
Chris Lattner | 8a886be | 2006-01-16 22:34:14 +0000 | [diff] [blame] | 4528 | <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a> |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4529 | </div> |
| 4530 | |
| 4531 | <div class="doc_text"> |
| 4532 | |
| 4533 | <h5>Syntax:</h5> |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 4534 | <p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any |
| 4535 | integer bit width. Not all targets support all bit widths however. |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4536 | <pre> |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 4537 | declare i32 @llvm.ctlz.i8 (i8 <src>) |
| 4538 | declare i32 @llvm.ctlz.i16(i16 <src>) |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 4539 | declare i32 @llvm.ctlz.i32(i32 <src>) |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 4540 | declare i32 @llvm.ctlz.i64(i64 <src>) |
| 4541 | declare i32 @llvm.ctlz.i256(i256 <src>) |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4542 | </pre> |
| 4543 | |
| 4544 | <h5>Overview:</h5> |
| 4545 | |
| 4546 | <p> |
Reid Spencer | 0b11820 | 2006-01-16 21:12:35 +0000 | [diff] [blame] | 4547 | The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of |
| 4548 | leading zeros in a variable. |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4549 | </p> |
| 4550 | |
| 4551 | <h5>Arguments:</h5> |
| 4552 | |
| 4553 | <p> |
Chris Lattner | cfe6b37 | 2005-05-07 01:46:40 +0000 | [diff] [blame] | 4554 | The only argument is the value to be counted. The argument may be of any |
Reid Spencer | a517338 | 2007-01-04 16:43:23 +0000 | [diff] [blame] | 4555 | integer type. The return type must match the argument type. |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4556 | </p> |
| 4557 | |
| 4558 | <h5>Semantics:</h5> |
| 4559 | |
| 4560 | <p> |
Chris Lattner | eff29ab | 2005-05-15 19:39:26 +0000 | [diff] [blame] | 4561 | The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros |
| 4562 | in a variable. If the src == 0 then the result is the size in bits of the type |
Reid Spencer | ca86e16 | 2006-12-31 07:07:53 +0000 | [diff] [blame] | 4563 | of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>. |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4564 | </p> |
| 4565 | </div> |
Chris Lattner | 3200628 | 2004-06-11 02:28:03 +0000 | [diff] [blame] | 4566 | |
| 4567 | |
Chris Lattner | eff29ab | 2005-05-15 19:39:26 +0000 | [diff] [blame] | 4568 | |
| 4569 | <!-- _______________________________________________________________________ --> |
| 4570 | <div class="doc_subsubsection"> |
Chris Lattner | 8a886be | 2006-01-16 22:34:14 +0000 | [diff] [blame] | 4571 | <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a> |
Chris Lattner | eff29ab | 2005-05-15 19:39:26 +0000 | [diff] [blame] | 4572 | </div> |
| 4573 | |
| 4574 | <div class="doc_text"> |
| 4575 | |
| 4576 | <h5>Syntax:</h5> |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 4577 | <p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any |
| 4578 | integer bit width. Not all targets support all bit widths however. |
Chris Lattner | eff29ab | 2005-05-15 19:39:26 +0000 | [diff] [blame] | 4579 | <pre> |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 4580 | declare i32 @llvm.cttz.i8 (i8 <src>) |
| 4581 | declare i32 @llvm.cttz.i16(i16 <src>) |
Anton Korobeynikov | ec43a06 | 2007-03-22 00:02:17 +0000 | [diff] [blame] | 4582 | declare i32 @llvm.cttz.i32(i32 <src>) |
Reid Spencer | 409e28f | 2007-04-01 08:04:23 +0000 | [diff] [blame] | 4583 | declare i32 @llvm.cttz.i64(i64 <src>) |
| 4584 | declare i32 @llvm.cttz.i256(i256 <src>) |
Chris Lattner | eff29ab | 2005-05-15 19:39:26 +0000 | [diff] [blame] | 4585 | </pre> |
| 4586 | |
| 4587 | <h5>Overview:</h5> |
| 4588 | |
| 4589 | <p> |
Reid Spencer | 0b11820 | 2006-01-16 21:12:35 +0000 | [diff] [blame] | 4590 | The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of |
| 4591 | trailing zeros. |
Chris Lattner | eff29ab | 2005-05-15 19:39:26 +0000 | [diff] [blame] | 4592 | </p> |
| 4593 | |
| 4594 | <h5>Arguments:</h5> |
| 4595 | |
| 4596 | <p> |
| 4597 | The only argument is the value to be counted. The argument may be of any |
Reid Spencer | a517338 | 2007-01-04 16:43:23 +0000 | [diff] [blame] | 4598 | integer type. The return type must match the argument type. |
Chris Lattner | eff29ab | 2005-05-15 19:39:26 +0000 | [diff] [blame] | 4599 | </p> |
| 4600 | |
| 4601 | <h5>Semantics:</h5> |
| 4602 | |
| 4603 | <p> |
| 4604 | The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros |
| 4605 | in a variable. If the src == 0 then the result is the size in bits of the type |
| 4606 | of src. For example, <tt>llvm.cttz(2) = 1</tt>. |
| 4607 | </p> |
| 4608 | </div> |
| 4609 | |
Reid Spencer | 497d93e | 2007-04-01 08:27:01 +0000 | [diff] [blame] | 4610 | <!-- _______________________________________________________________________ --> |
| 4611 | <div class="doc_subsubsection"> |
Reid Spencer | beacf66 | 2007-04-10 02:51:31 +0000 | [diff] [blame] | 4612 | <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a> |
Reid Spencer | a13ba7d | 2007-04-01 19:00:37 +0000 | [diff] [blame] | 4613 | </div> |
| 4614 | |
| 4615 | <div class="doc_text"> |
| 4616 | |
| 4617 | <h5>Syntax:</h5> |
Reid Spencer | beacf66 | 2007-04-10 02:51:31 +0000 | [diff] [blame] | 4618 | <p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt> |
Reid Spencer | a13ba7d | 2007-04-01 19:00:37 +0000 | [diff] [blame] | 4619 | on any integer bit width. |
| 4620 | <pre> |
Reid Spencer | beacf66 | 2007-04-10 02:51:31 +0000 | [diff] [blame] | 4621 | declare i17 @llvm.part.select.i17.i17 (i17 %val, i32 %loBit, i32 %hiBit) |
| 4622 | declare i29 @llvm.part.select.i29.i29 (i29 %val, i32 %loBit, i32 %hiBit) |
Reid Spencer | a13ba7d | 2007-04-01 19:00:37 +0000 | [diff] [blame] | 4623 | </pre> |
| 4624 | |
| 4625 | <h5>Overview:</h5> |
Reid Spencer | beacf66 | 2007-04-10 02:51:31 +0000 | [diff] [blame] | 4626 | <p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a |
Reid Spencer | a13ba7d | 2007-04-01 19:00:37 +0000 | [diff] [blame] | 4627 | range of bits from an integer value and returns them in the same bit width as |
| 4628 | the original value.</p> |
| 4629 | |
| 4630 | <h5>Arguments:</h5> |
| 4631 | <p>The first argument, <tt>%val</tt> and the result may be integer types of |
| 4632 | any bit width but they must have the same bit width. The second and third |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4633 | arguments must be <tt>i32</tt> type since they specify only a bit index.</p> |
Reid Spencer | a13ba7d | 2007-04-01 19:00:37 +0000 | [diff] [blame] | 4634 | |
| 4635 | <h5>Semantics:</h5> |
Reid Spencer | beacf66 | 2007-04-10 02:51:31 +0000 | [diff] [blame] | 4636 | <p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4637 | of operation: forwards and reverse. If <tt>%loBit</tt> is greater than |
| 4638 | <tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it |
| 4639 | operates in forward mode.</p> |
| 4640 | <p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt> |
| 4641 | right by <tt>%loBit</tt> bits and then ANDing it with a mask with |
Reid Spencer | a13ba7d | 2007-04-01 19:00:37 +0000 | [diff] [blame] | 4642 | only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p> |
| 4643 | <ol> |
| 4644 | <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified |
| 4645 | by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li> |
| 4646 | <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value |
| 4647 | to determine the number of bits to retain.</li> |
| 4648 | <li>A mask of the retained bits is created by shifting a -1 value.</li> |
| 4649 | <li>The mask is ANDed with <tt>%val</tt> to produce the result. |
| 4650 | </ol> |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4651 | <p>In reverse mode, a similar computation is made except that:</p> |
| 4652 | <ol> |
| 4653 | <li>The bits selected wrap around to include both the highest and lowest bits. |
Reid Spencer | beacf66 | 2007-04-10 02:51:31 +0000 | [diff] [blame] | 4654 | For example, part.select(i16 X, 4, 7) selects bits from X with a mask of |
| 4655 | 0x00F0 (forwards case) while part.select(i16 X, 8, 3) selects bits from X |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4656 | with a mask of 0xFF0F.</li> |
| 4657 | <li>The bits returned in the reverse case are reversed. So, if X has the value |
Reid Spencer | beacf66 | 2007-04-10 02:51:31 +0000 | [diff] [blame] | 4658 | 0x6ACF and we apply part.select(i16 X, 8, 3) to it, we get back the value |
Reid Spencer | a3e435f | 2007-04-04 02:42:35 +0000 | [diff] [blame] | 4659 | 0x0A6F.</li> |
| 4660 | </ol> |
Reid Spencer | a13ba7d | 2007-04-01 19:00:37 +0000 | [diff] [blame] | 4661 | </div> |
| 4662 | |
Reid Spencer | f86037f | 2007-04-11 23:23:49 +0000 | [diff] [blame] | 4663 | <div class="doc_subsubsection"> |
| 4664 | <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a> |
| 4665 | </div> |
| 4666 | |
| 4667 | <div class="doc_text"> |
| 4668 | |
| 4669 | <h5>Syntax:</h5> |
| 4670 | <p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt> |
| 4671 | on any integer bit width. |
| 4672 | <pre> |
| 4673 | declare i17 @llvm.part.set.i17.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi) |
| 4674 | declare i29 @llvm.part.set.i29.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi) |
| 4675 | </pre> |
| 4676 | |
| 4677 | <h5>Overview:</h5> |
| 4678 | <p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range |
| 4679 | of bits in an integer value with another integer value. It returns the integer |
| 4680 | with the replaced bits.</p> |
| 4681 | |
| 4682 | <h5>Arguments:</h5> |
| 4683 | <p>The first argument, <tt>%val</tt> and the result may be integer types of |
| 4684 | any bit width but they must have the same bit width. <tt>%val</tt> is the value |
| 4685 | whose bits will be replaced. The second argument, <tt>%repl</tt> may be an |
| 4686 | integer of any bit width. The third and fourth arguments must be <tt>i32</tt> |
| 4687 | type since they specify only a bit index.</p> |
| 4688 | |
| 4689 | <h5>Semantics:</h5> |
| 4690 | <p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes |
| 4691 | of operation: forwards and reverse. If <tt>%lo</tt> is greater than |
| 4692 | <tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it |
| 4693 | operates in forward mode.</p> |
| 4694 | <p>For both modes, the <tt>%repl</tt> value is prepared for use by either |
| 4695 | truncating it down to the size of the replacement area or zero extending it |
| 4696 | up to that size.</p> |
| 4697 | <p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive) |
| 4698 | are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit |
| 4699 | in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up |
| 4700 | to the <tt>%hi</tt>th bit. |
| 4701 | <p>In reverse mode, a similar computation is made except that the bits replaced |
| 4702 | wrap around to include both the highest and lowest bits. For example, if a |
| 4703 | 16 bit value is being replaced then <tt>%lo=8</tt> and <tt>%hi=4</tt> would |
Reid Spencer | 065cc7f | 2007-04-11 23:46:06 +0000 | [diff] [blame] | 4704 | cause these bits to be set: <tt>0xFF1F</tt>.</p> |
Reid Spencer | f86037f | 2007-04-11 23:23:49 +0000 | [diff] [blame] | 4705 | <h5>Examples:</h5> |
| 4706 | <pre> |
Reid Spencer | f0dbf64 | 2007-04-12 01:03:03 +0000 | [diff] [blame] | 4707 | llvm.part.set(0xFFFF, 0, 4, 7) -> 0xFF0F |
| 4708 | llvm.part.set(0xFFFF, 0, 7, 4) -> 0x0060 |
| 4709 | llvm.part.set(0xFFFF, 0, 8, 3) -> 0x00F0 |
| 4710 | llvm.part.set(0xFFFF, 0, 3, 8) -> 0xFE07 |
Reid Spencer | c891084 | 2007-04-11 23:49:50 +0000 | [diff] [blame] | 4711 | </pre> |
Reid Spencer | f86037f | 2007-04-11 23:23:49 +0000 | [diff] [blame] | 4712 | </div> |
| 4713 | |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 4714 | <!-- ======================================================================= --> |
| 4715 | <div class="doc_subsection"> |
| 4716 | <a name="int_debugger">Debugger Intrinsics</a> |
| 4717 | </div> |
| 4718 | |
| 4719 | <div class="doc_text"> |
| 4720 | <p> |
| 4721 | The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix), |
| 4722 | are described in the <a |
| 4723 | href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level |
| 4724 | Debugging</a> document. |
| 4725 | </p> |
| 4726 | </div> |
| 4727 | |
| 4728 | |
Jim Laskey | dd4ef1b | 2007-03-14 19:31:19 +0000 | [diff] [blame] | 4729 | <!-- ======================================================================= --> |
| 4730 | <div class="doc_subsection"> |
| 4731 | <a name="int_eh">Exception Handling Intrinsics</a> |
| 4732 | </div> |
| 4733 | |
| 4734 | <div class="doc_text"> |
| 4735 | <p> The LLVM exception handling intrinsics (which all start with |
| 4736 | <tt>llvm.eh.</tt> prefix), are described in the <a |
| 4737 | href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception |
| 4738 | Handling</a> document. </p> |
| 4739 | </div> |
| 4740 | |
| 4741 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 4742 | <!-- *********************************************************************** --> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 4743 | <hr> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 4744 | <address> |
| 4745 | <a href="http://jigsaw.w3.org/css-validator/check/referer"><img |
| 4746 | src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a> |
| 4747 | <a href="http://validator.w3.org/check/referer"><img |
| 4748 | src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a> |
| 4749 | |
| 4750 | <a href="mailto:sabre@nondot.org">Chris Lattner</a><br> |
Reid Spencer | 05fe4b0 | 2006-03-14 05:39:39 +0000 | [diff] [blame] | 4751 | <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 4752 | Last modified: $Date$ |
| 4753 | </address> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 4754 | </body> |
| 4755 | </html> |