1 =pod 2 3 =head1 NAME 4 5 llvm-bcanalyzer - LLVM bitcode analyzer 6 7 =head1 SYNOPSIS 8 9 B<llvm-bcanalyzer> [I<options>] [F<filename>] 10 11 =head1 DESCRIPTION 12 13 The B<llvm-bcanalyzer> command is a small utility for analyzing bitcode files. 14 The tool reads a bitcode file (such as generated with the B<llvm-as> tool) and 15 produces a statistical report on the contents of the bitcode file. The tool 16 can also dump a low level but human readable version of the bitcode file. 17 This tool is probably not of much interest or utility except for those working 18 directly with the bitcode file format. Most LLVM users can just ignore 19 this tool. 20 21 If F<filename> is omitted or is C<->, then B<llvm-bcanalyzer> reads its input 22 from standard input. This is useful for combining the tool into a pipeline. 23 Output is written to the standard output. 24 25 =head1 OPTIONS 26 27 =over 28 29 =item B<-nodetails> 30 31 Causes B<llvm-bcanalyzer> to abbreviate its output by writing out only a module 32 level summary. The details for individual functions are not displayed. 33 34 =item B<-dump> 35 36 Causes B<llvm-bcanalyzer> to dump the bitcode in a human readable format. This 37 format is significantly different from LLVM assembly and provides details about 38 the encoding of the bitcode file. 39 40 =item B<-verify> 41 42 Causes B<llvm-bcanalyzer> to verify the module produced by reading the 43 bitcode. This ensures that the statistics generated are based on a consistent 44 module. 45 46 =item B<-help> 47 48 Print a summary of command line options. 49 50 =back 51 52 =head1 EXIT STATUS 53 54 If B<llvm-bcanalyzer> succeeds, it will exit with 0. Otherwise, if an error 55 occurs, it will exit with a non-zero value, usually 1. 56 57 =head1 SUMMARY OUTPUT DEFINITIONS 58 59 The following items are always printed by llvm-bcanalyzer. They comprize the 60 summary output. 61 62 =over 63 64 =item B<Bitcode Analysis Of Module> 65 66 This just provides the name of the module for which bitcode analysis is being 67 generated. 68 69 =item B<Bitcode Version Number> 70 71 The bitcode version (not LLVM version) of the file read by the analyzer. 72 73 =item B<File Size> 74 75 The size, in bytes, of the entire bitcode file. 76 77 =item B<Module Bytes> 78 79 The size, in bytes, of the module block. Percentage is relative to File Size. 80 81 =item B<Function Bytes> 82 83 The size, in bytes, of all the function blocks. Percentage is relative to File 84 Size. 85 86 =item B<Global Types Bytes> 87 88 The size, in bytes, of the Global Types Pool. Percentage is relative to File 89 Size. This is the size of the definitions of all types in the bitcode file. 90 91 =item B<Constant Pool Bytes> 92 93 The size, in bytes, of the Constant Pool Blocks Percentage is relative to File 94 Size. 95 96 =item B<Module Globals Bytes> 97 98 Ths size, in bytes, of the Global Variable Definitions and their initializers. 99 Percentage is relative to File Size. 100 101 =item B<Instruction List Bytes> 102 103 The size, in bytes, of all the instruction lists in all the functions. 104 Percentage is relative to File Size. Note that this value is also included in 105 the Function Bytes. 106 107 =item B<Compaction Table Bytes> 108 109 The size, in bytes, of all the compaction tables in all the functions. 110 Percentage is relative to File Size. Note that this value is also included in 111 the Function Bytes. 112 113 =item B<Symbol Table Bytes> 114 115 The size, in bytes, of all the symbol tables in all the functions. Percentage is 116 relative to File Size. Note that this value is also included in the Function 117 Bytes. 118 119 =item B<Dependent Libraries Bytes> 120 121 The size, in bytes, of the list of dependent libraries in the module. Percentage 122 is relative to File Size. Note that this value is also included in the Module 123 Global Bytes. 124 125 =item B<Number Of Bitcode Blocks> 126 127 The total number of blocks of any kind in the bitcode file. 128 129 =item B<Number Of Functions> 130 131 The total number of function definitions in the bitcode file. 132 133 =item B<Number Of Types> 134 135 The total number of types defined in the Global Types Pool. 136 137 =item B<Number Of Constants> 138 139 The total number of constants (of any type) defined in the Constant Pool. 140 141 =item B<Number Of Basic Blocks> 142 143 The total number of basic blocks defined in all functions in the bitcode file. 144 145 =item B<Number Of Instructions> 146 147 The total number of instructions defined in all functions in the bitcode file. 148 149 =item B<Number Of Long Instructions> 150 151 The total number of long instructions defined in all functions in the bitcode 152 file. Long instructions are those taking greater than 4 bytes. Typically long 153 instructions are GetElementPtr with several indices, PHI nodes, and calls to 154 functions with large numbers of arguments. 155 156 =item B<Number Of Operands> 157 158 The total number of operands used in all instructions in the bitcode file. 159 160 =item B<Number Of Compaction Tables> 161 162 The total number of compaction tables in all functions in the bitcode file. 163 164 =item B<Number Of Symbol Tables> 165 166 The total number of symbol tables in all functions in the bitcode file. 167 168 =item B<Number Of Dependent Libs> 169 170 The total number of dependent libraries found in the bitcode file. 171 172 =item B<Total Instruction Size> 173 174 The total size of the instructions in all functions in the bitcode file. 175 176 =item B<Average Instruction Size> 177 178 The average number of bytes per instruction across all functions in the bitcode 179 file. This value is computed by dividing Total Instruction Size by Number Of 180 Instructions. 181 182 =item B<Maximum Type Slot Number> 183 184 The maximum value used for a type's slot number. Larger slot number values take 185 more bytes to encode. 186 187 =item B<Maximum Value Slot Number> 188 189 The maximum value used for a value's slot number. Larger slot number values take 190 more bytes to encode. 191 192 =item B<Bytes Per Value> 193 194 The average size of a Value definition (of any type). This is computed by 195 dividing File Size by the total number of values of any type. 196 197 =item B<Bytes Per Global> 198 199 The average size of a global definition (constants and global variables). 200 201 =item B<Bytes Per Function> 202 203 The average number of bytes per function definition. This is computed by 204 dividing Function Bytes by Number Of Functions. 205 206 =item B<# of VBR 32-bit Integers> 207 208 The total number of 32-bit integers encoded using the Variable Bit Rate 209 encoding scheme. 210 211 =item B<# of VBR 64-bit Integers> 212 213 The total number of 64-bit integers encoded using the Variable Bit Rate encoding 214 scheme. 215 216 =item B<# of VBR Compressed Bytes> 217 218 The total number of bytes consumed by the 32-bit and 64-bit integers that use 219 the Variable Bit Rate encoding scheme. 220 221 =item B<# of VBR Expanded Bytes> 222 223 The total number of bytes that would have been consumed by the 32-bit and 64-bit 224 integers had they not been compressed with the Variable Bit Rage encoding 225 scheme. 226 227 =item B<Bytes Saved With VBR> 228 229 The total number of bytes saved by using the Variable Bit Rate encoding scheme. 230 The percentage is relative to # of VBR Expanded Bytes. 231 232 =back 233 234 =head1 DETAILED OUTPUT DEFINITIONS 235 236 The following definitions occur only if the -nodetails option was not given. 237 The detailed output provides additional information on a per-function basis. 238 239 =over 240 241 =item B<Type> 242 243 The type signature of the function. 244 245 =item B<Byte Size> 246 247 The total number of bytes in the function's block. 248 249 =item B<Basic Blocks> 250 251 The number of basic blocks defined by the function. 252 253 =item B<Instructions> 254 255 The number of instructions defined by the function. 256 257 =item B<Long Instructions> 258 259 The number of instructions using the long instruction format in the function. 260 261 =item B<Operands> 262 263 The number of operands used by all instructions in the function. 264 265 =item B<Instruction Size> 266 267 The number of bytes consumed by instructions in the function. 268 269 =item B<Average Instruction Size> 270 271 The average number of bytes consumed by the instructions in the function. This 272 value is computed by dividing Instruction Size by Instructions. 273 274 =item B<Bytes Per Instruction> 275 276 The average number of bytes used by the function per instruction. This value is 277 computed by dividing Byte Size by Instructions. Note that this is not the same 278 as Average Instruction Size. It computes a number relative to the total function 279 size not just the size of the instruction list. 280 281 =item B<Number of VBR 32-bit Integers> 282 283 The total number of 32-bit integers found in this function (for any use). 284 285 =item B<Number of VBR 64-bit Integers> 286 287 The total number of 64-bit integers found in this function (for any use). 288 289 =item B<Number of VBR Compressed Bytes> 290 291 The total number of bytes in this function consumed by the 32-bit and 64-bit 292 integers that use the Variable Bit Rate encoding scheme. 293 294 =item B<Number of VBR Expanded Bytes> 295 296 The total number of bytes in this function that would have been consumed by 297 the 32-bit and 64-bit integers had they not been compressed with the Variable 298 Bit Rate encoding scheme. 299 300 =item B<Bytes Saved With VBR> 301 302 The total number of bytes saved in this function by using the Variable Bit 303 Rate encoding scheme. The percentage is relative to # of VBR Expanded Bytes. 304 305 =back 306 307 =head1 SEE ALSO 308 309 L<llvm-dis|llvm-dis>, L<http://llvm.org/docs/BitCodeFormat.html> 310 311 =head1 AUTHORS 312 313 Maintained by the LLVM Team (L<http://llvm.org/>). 314 315 =cut 316
