Mercurial > hg > CbC > CbC_gcc
annotate gcc/doc/gcov.1 @ 19:58ad6c70ea60
update gcc from 4.4.0 to 4.4.1.
| author | kent@firefly.cr.ie.u-ryukyu.ac.jp |
|---|---|
| date | Thu, 24 Sep 2009 13:21:57 +0900 |
| parents | a06113de4d67 |
| children | 3bfb6c00c1e0 |
| rev | line source |
|---|---|
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| 132 .\" ======================================================================== | |
| 133 .\" | |
| 134 .IX Title "GCOV 1" | |
|
19
58ad6c70ea60
update gcc from 4.4.0 to 4.4.1.
kent@firefly.cr.ie.u-ryukyu.ac.jp
parents:
0
diff
changeset
|
135 .TH GCOV 1 "2009-07-22" "gcc-4.4.1" "GNU" |
| 0 | 136 .\" For nroff, turn off justification. Always turn off hyphenation; it makes |
| 137 .\" way too many mistakes in technical documents. | |
| 138 .if n .ad l | |
| 139 .nh | |
| 140 .SH "NAME" | |
| 141 gcov \- coverage testing tool | |
| 142 .SH "SYNOPSIS" | |
| 143 .IX Header "SYNOPSIS" | |
| 144 gcov [\fB\-v\fR|\fB\-\-version\fR] [\fB\-h\fR|\fB\-\-help\fR] | |
| 145 [\fB\-a\fR|\fB\-\-all\-blocks\fR] | |
| 146 [\fB\-b\fR|\fB\-\-branch\-probabilities\fR] | |
| 147 [\fB\-c\fR|\fB\-\-branch\-counts\fR] | |
| 148 [\fB\-n\fR|\fB\-\-no\-output\fR] | |
| 149 [\fB\-l\fR|\fB\-\-long\-file\-names\fR] | |
| 150 [\fB\-p\fR|\fB\-\-preserve\-paths\fR] | |
| 151 [\fB\-f\fR|\fB\-\-function\-summaries\fR] | |
| 152 [\fB\-o\fR|\fB\-\-object\-directory\fR \fIdirectory|file\fR] \fIsourcefiles\fR | |
| 153 [\fB\-u\fR|\fB\-\-unconditional\-branches\fR] | |
| 154 .SH "DESCRIPTION" | |
| 155 .IX Header "DESCRIPTION" | |
| 156 \&\fBgcov\fR is a test coverage program. Use it in concert with \s-1GCC\s0 | |
| 157 to analyze your programs to help create more efficient, faster running | |
| 158 code and to discover untested parts of your program. You can use | |
| 159 \&\fBgcov\fR as a profiling tool to help discover where your | |
| 160 optimization efforts will best affect your code. You can also use | |
| 161 \&\fBgcov\fR along with the other profiling tool, \fBgprof\fR, to | |
| 162 assess which parts of your code use the greatest amount of computing | |
| 163 time. | |
| 164 .PP | |
| 165 Profiling tools help you analyze your code's performance. Using a | |
| 166 profiler such as \fBgcov\fR or \fBgprof\fR, you can find out some | |
| 167 basic performance statistics, such as: | |
| 168 .IP "\(bu" 4 | |
| 169 how often each line of code executes | |
| 170 .IP "\(bu" 4 | |
| 171 what lines of code are actually executed | |
| 172 .IP "\(bu" 4 | |
| 173 how much computing time each section of code uses | |
| 174 .PP | |
| 175 Once you know these things about how your code works when compiled, you | |
| 176 can look at each module to see which modules should be optimized. | |
| 177 \&\fBgcov\fR helps you determine where to work on optimization. | |
| 178 .PP | |
| 179 Software developers also use coverage testing in concert with | |
| 180 testsuites, to make sure software is actually good enough for a release. | |
| 181 Testsuites can verify that a program works as expected; a coverage | |
| 182 program tests to see how much of the program is exercised by the | |
| 183 testsuite. Developers can then determine what kinds of test cases need | |
| 184 to be added to the testsuites to create both better testing and a better | |
| 185 final product. | |
| 186 .PP | |
| 187 You should compile your code without optimization if you plan to use | |
| 188 \&\fBgcov\fR because the optimization, by combining some lines of code | |
| 189 into one function, may not give you as much information as you need to | |
| 190 look for `hot spots' where the code is using a great deal of computer | |
| 191 time. Likewise, because \fBgcov\fR accumulates statistics by line (at | |
| 192 the lowest resolution), it works best with a programming style that | |
| 193 places only one statement on each line. If you use complicated macros | |
| 194 that expand to loops or to other control structures, the statistics are | |
| 195 less helpful\-\-\-they only report on the line where the macro call | |
| 196 appears. If your complex macros behave like functions, you can replace | |
| 197 them with inline functions to solve this problem. | |
| 198 .PP | |
| 199 \&\fBgcov\fR creates a logfile called \fI\fIsourcefile\fI.gcov\fR which | |
| 200 indicates how many times each line of a source file \fI\fIsourcefile\fI.c\fR | |
| 201 has executed. You can use these logfiles along with \fBgprof\fR to aid | |
| 202 in fine-tuning the performance of your programs. \fBgprof\fR gives | |
| 203 timing information you can use along with the information you get from | |
| 204 \&\fBgcov\fR. | |
| 205 .PP | |
| 206 \&\fBgcov\fR works only on code compiled with \s-1GCC\s0. It is not | |
| 207 compatible with any other profiling or test coverage mechanism. | |
| 208 .SH "OPTIONS" | |
| 209 .IX Header "OPTIONS" | |
| 210 .IP "\fB\-h\fR" 4 | |
| 211 .IX Item "-h" | |
| 212 .PD 0 | |
| 213 .IP "\fB\-\-help\fR" 4 | |
| 214 .IX Item "--help" | |
| 215 .PD | |
| 216 Display help about using \fBgcov\fR (on the standard output), and | |
| 217 exit without doing any further processing. | |
| 218 .IP "\fB\-v\fR" 4 | |
| 219 .IX Item "-v" | |
| 220 .PD 0 | |
| 221 .IP "\fB\-\-version\fR" 4 | |
| 222 .IX Item "--version" | |
| 223 .PD | |
| 224 Display the \fBgcov\fR version number (on the standard output), | |
| 225 and exit without doing any further processing. | |
| 226 .IP "\fB\-a\fR" 4 | |
| 227 .IX Item "-a" | |
| 228 .PD 0 | |
| 229 .IP "\fB\-\-all\-blocks\fR" 4 | |
| 230 .IX Item "--all-blocks" | |
| 231 .PD | |
| 232 Write individual execution counts for every basic block. Normally gcov | |
| 233 outputs execution counts only for the main blocks of a line. With this | |
| 234 option you can determine if blocks within a single line are not being | |
| 235 executed. | |
| 236 .IP "\fB\-b\fR" 4 | |
| 237 .IX Item "-b" | |
| 238 .PD 0 | |
| 239 .IP "\fB\-\-branch\-probabilities\fR" 4 | |
| 240 .IX Item "--branch-probabilities" | |
| 241 .PD | |
| 242 Write branch frequencies to the output file, and write branch summary | |
| 243 info to the standard output. This option allows you to see how often | |
| 244 each branch in your program was taken. Unconditional branches will not | |
| 245 be shown, unless the \fB\-u\fR option is given. | |
| 246 .IP "\fB\-c\fR" 4 | |
| 247 .IX Item "-c" | |
| 248 .PD 0 | |
| 249 .IP "\fB\-\-branch\-counts\fR" 4 | |
| 250 .IX Item "--branch-counts" | |
| 251 .PD | |
| 252 Write branch frequencies as the number of branches taken, rather than | |
| 253 the percentage of branches taken. | |
| 254 .IP "\fB\-n\fR" 4 | |
| 255 .IX Item "-n" | |
| 256 .PD 0 | |
| 257 .IP "\fB\-\-no\-output\fR" 4 | |
| 258 .IX Item "--no-output" | |
| 259 .PD | |
| 260 Do not create the \fBgcov\fR output file. | |
| 261 .IP "\fB\-l\fR" 4 | |
| 262 .IX Item "-l" | |
| 263 .PD 0 | |
| 264 .IP "\fB\-\-long\-file\-names\fR" 4 | |
| 265 .IX Item "--long-file-names" | |
| 266 .PD | |
| 267 Create long file names for included source files. For example, if the | |
| 268 header file \fIx.h\fR contains code, and was included in the file | |
| 269 \&\fIa.c\fR, then running \fBgcov\fR on the file \fIa.c\fR will produce | |
| 270 an output file called \fIa.c##x.h.gcov\fR instead of \fIx.h.gcov\fR. | |
| 271 This can be useful if \fIx.h\fR is included in multiple source | |
| 272 files. If you use the \fB\-p\fR option, both the including and | |
| 273 included file names will be complete path names. | |
| 274 .IP "\fB\-p\fR" 4 | |
| 275 .IX Item "-p" | |
| 276 .PD 0 | |
| 277 .IP "\fB\-\-preserve\-paths\fR" 4 | |
| 278 .IX Item "--preserve-paths" | |
| 279 .PD | |
| 280 Preserve complete path information in the names of generated | |
| 281 \&\fI.gcov\fR files. Without this option, just the filename component is | |
| 282 used. With this option, all directories are used, with \fB/\fR characters | |
| 283 translated to \fB#\fR characters, \fI.\fR directory components | |
| 284 removed and \fI..\fR | |
| 285 components renamed to \fB^\fR. This is useful if sourcefiles are in several | |
| 286 different directories. It also affects the \fB\-l\fR option. | |
| 287 .IP "\fB\-f\fR" 4 | |
| 288 .IX Item "-f" | |
| 289 .PD 0 | |
| 290 .IP "\fB\-\-function\-summaries\fR" 4 | |
| 291 .IX Item "--function-summaries" | |
| 292 .PD | |
| 293 Output summaries for each function in addition to the file level summary. | |
| 294 .IP "\fB\-o\fR \fIdirectory|file\fR" 4 | |
| 295 .IX Item "-o directory|file" | |
| 296 .PD 0 | |
| 297 .IP "\fB\-\-object\-directory\fR \fIdirectory\fR" 4 | |
| 298 .IX Item "--object-directory directory" | |
| 299 .IP "\fB\-\-object\-file\fR \fIfile\fR" 4 | |
| 300 .IX Item "--object-file file" | |
| 301 .PD | |
| 302 Specify either the directory containing the gcov data files, or the | |
| 303 object path name. The \fI.gcno\fR, and | |
| 304 \&\fI.gcda\fR data files are searched for using this option. If a directory | |
| 305 is specified, the data files are in that directory and named after the | |
| 306 source file name, without its extension. If a file is specified here, | |
| 307 the data files are named after that file, without its extension. If this | |
| 308 option is not supplied, it defaults to the current directory. | |
| 309 .IP "\fB\-u\fR" 4 | |
| 310 .IX Item "-u" | |
| 311 .PD 0 | |
| 312 .IP "\fB\-\-unconditional\-branches\fR" 4 | |
| 313 .IX Item "--unconditional-branches" | |
| 314 .PD | |
| 315 When branch probabilities are given, include those of unconditional branches. | |
| 316 Unconditional branches are normally not interesting. | |
| 317 .PP | |
| 318 \&\fBgcov\fR should be run with the current directory the same as that | |
| 319 when you invoked the compiler. Otherwise it will not be able to locate | |
| 320 the source files. \fBgcov\fR produces files called | |
| 321 \&\fI\fImangledname\fI.gcov\fR in the current directory. These contain | |
| 322 the coverage information of the source file they correspond to. | |
| 323 One \fI.gcov\fR file is produced for each source file containing code, | |
| 324 which was compiled to produce the data files. The \fImangledname\fR part | |
| 325 of the output file name is usually simply the source file name, but can | |
| 326 be something more complicated if the \fB\-l\fR or \fB\-p\fR options are | |
| 327 given. Refer to those options for details. | |
| 328 .PP | |
| 329 The \fI.gcov\fR files contain the \fB:\fR separated fields along with | |
| 330 program source code. The format is | |
| 331 .PP | |
| 332 .Vb 1 | |
| 333 \& <execution_count>:<line_number>:<source line text> | |
| 334 .Ve | |
| 335 .PP | |
| 336 Additional block information may succeed each line, when requested by | |
| 337 command line option. The \fIexecution_count\fR is \fB\-\fR for lines | |
| 338 containing no code and \fB#####\fR for lines which were never executed. | |
| 339 Some lines of information at the start have \fIline_number\fR of zero. | |
| 340 .PP | |
| 341 The preamble lines are of the form | |
| 342 .PP | |
| 343 .Vb 1 | |
| 344 \& \-:0:<tag>:<value> | |
| 345 .Ve | |
| 346 .PP | |
| 347 The ordering and number of these preamble lines will be augmented as | |
| 348 \&\fBgcov\fR development progresses \-\-\- do not rely on them remaining | |
| 349 unchanged. Use \fItag\fR to locate a particular preamble line. | |
| 350 .PP | |
| 351 The additional block information is of the form | |
| 352 .PP | |
| 353 .Vb 1 | |
| 354 \& <tag> <information> | |
| 355 .Ve | |
| 356 .PP | |
| 357 The \fIinformation\fR is human readable, but designed to be simple | |
| 358 enough for machine parsing too. | |
| 359 .PP | |
| 360 When printing percentages, 0% and 100% are only printed when the values | |
| 361 are \fIexactly\fR 0% and 100% respectively. Other values which would | |
| 362 conventionally be rounded to 0% or 100% are instead printed as the | |
| 363 nearest non-boundary value. | |
| 364 .PP | |
| 365 When using \fBgcov\fR, you must first compile your program with two | |
| 366 special \s-1GCC\s0 options: \fB\-fprofile\-arcs \-ftest\-coverage\fR. | |
| 367 This tells the compiler to generate additional information needed by | |
| 368 gcov (basically a flow graph of the program) and also includes | |
| 369 additional code in the object files for generating the extra profiling | |
| 370 information needed by gcov. These additional files are placed in the | |
| 371 directory where the object file is located. | |
| 372 .PP | |
| 373 Running the program will cause profile output to be generated. For each | |
| 374 source file compiled with \fB\-fprofile\-arcs\fR, an accompanying | |
| 375 \&\fI.gcda\fR file will be placed in the object file directory. | |
| 376 .PP | |
| 377 Running \fBgcov\fR with your program's source file names as arguments | |
| 378 will now produce a listing of the code along with frequency of execution | |
| 379 for each line. For example, if your program is called \fItmp.c\fR, this | |
| 380 is what you see when you use the basic \fBgcov\fR facility: | |
| 381 .PP | |
| 382 .Vb 5 | |
| 383 \& $ gcc \-fprofile\-arcs \-ftest\-coverage tmp.c | |
| 384 \& $ a.out | |
| 385 \& $ gcov tmp.c | |
| 386 \& 90.00% of 10 source lines executed in file tmp.c | |
| 387 \& Creating tmp.c.gcov. | |
| 388 .Ve | |
| 389 .PP | |
| 390 The file \fItmp.c.gcov\fR contains output from \fBgcov\fR. | |
| 391 Here is a sample: | |
| 392 .PP | |
| 393 .Vb 10 | |
| 394 \& \-: 0:Source:tmp.c | |
| 395 \& \-: 0:Graph:tmp.gcno | |
| 396 \& \-: 0:Data:tmp.gcda | |
| 397 \& \-: 0:Runs:1 | |
| 398 \& \-: 0:Programs:1 | |
| 399 \& \-: 1:#include <stdio.h> | |
| 400 \& \-: 2: | |
| 401 \& \-: 3:int main (void) | |
| 402 \& 1: 4:{ | |
| 403 \& 1: 5: int i, total; | |
| 404 \& \-: 6: | |
| 405 \& 1: 7: total = 0; | |
| 406 \& \-: 8: | |
| 407 \& 11: 9: for (i = 0; i < 10; i++) | |
| 408 \& 10: 10: total += i; | |
| 409 \& \-: 11: | |
| 410 \& 1: 12: if (total != 45) | |
| 411 \& #####: 13: printf ("Failure\en"); | |
| 412 \& \-: 14: else | |
| 413 \& 1: 15: printf ("Success\en"); | |
| 414 \& 1: 16: return 0; | |
| 415 \& \-: 17:} | |
| 416 .Ve | |
| 417 .PP | |
| 418 When you use the \fB\-a\fR option, you will get individual block | |
| 419 counts, and the output looks like this: | |
| 420 .PP | |
| 421 .Vb 10 | |
| 422 \& \-: 0:Source:tmp.c | |
| 423 \& \-: 0:Graph:tmp.gcno | |
| 424 \& \-: 0:Data:tmp.gcda | |
| 425 \& \-: 0:Runs:1 | |
| 426 \& \-: 0:Programs:1 | |
| 427 \& \-: 1:#include <stdio.h> | |
| 428 \& \-: 2: | |
| 429 \& \-: 3:int main (void) | |
| 430 \& 1: 4:{ | |
| 431 \& 1: 4\-block 0 | |
| 432 \& 1: 5: int i, total; | |
| 433 \& \-: 6: | |
| 434 \& 1: 7: total = 0; | |
| 435 \& \-: 8: | |
| 436 \& 11: 9: for (i = 0; i < 10; i++) | |
| 437 \& 11: 9\-block 0 | |
| 438 \& 10: 10: total += i; | |
| 439 \& 10: 10\-block 0 | |
| 440 \& \-: 11: | |
| 441 \& 1: 12: if (total != 45) | |
| 442 \& 1: 12\-block 0 | |
| 443 \& #####: 13: printf ("Failure\en"); | |
| 444 \& $$$$$: 13\-block 0 | |
| 445 \& \-: 14: else | |
| 446 \& 1: 15: printf ("Success\en"); | |
| 447 \& 1: 15\-block 0 | |
| 448 \& 1: 16: return 0; | |
| 449 \& 1: 16\-block 0 | |
| 450 \& \-: 17:} | |
| 451 .Ve | |
| 452 .PP | |
| 453 In this mode, each basic block is only shown on one line \*(-- the last | |
| 454 line of the block. A multi-line block will only contribute to the | |
| 455 execution count of that last line, and other lines will not be shown | |
| 456 to contain code, unless previous blocks end on those lines. | |
| 457 The total execution count of a line is shown and subsequent lines show | |
| 458 the execution counts for individual blocks that end on that line. After each | |
| 459 block, the branch and call counts of the block will be shown, if the | |
| 460 \&\fB\-b\fR option is given. | |
| 461 .PP | |
| 462 Because of the way \s-1GCC\s0 instruments calls, a call count can be shown | |
| 463 after a line with no individual blocks. | |
| 464 As you can see, line 13 contains a basic block that was not executed. | |
| 465 .PP | |
| 466 When you use the \fB\-b\fR option, your output looks like this: | |
| 467 .PP | |
| 468 .Vb 6 | |
| 469 \& $ gcov \-b tmp.c | |
| 470 \& 90.00% of 10 source lines executed in file tmp.c | |
| 471 \& 80.00% of 5 branches executed in file tmp.c | |
| 472 \& 80.00% of 5 branches taken at least once in file tmp.c | |
| 473 \& 50.00% of 2 calls executed in file tmp.c | |
| 474 \& Creating tmp.c.gcov. | |
| 475 .Ve | |
| 476 .PP | |
| 477 Here is a sample of a resulting \fItmp.c.gcov\fR file: | |
| 478 .PP | |
| 479 .Vb 10 | |
| 480 \& \-: 0:Source:tmp.c | |
| 481 \& \-: 0:Graph:tmp.gcno | |
| 482 \& \-: 0:Data:tmp.gcda | |
| 483 \& \-: 0:Runs:1 | |
| 484 \& \-: 0:Programs:1 | |
| 485 \& \-: 1:#include <stdio.h> | |
| 486 \& \-: 2: | |
| 487 \& \-: 3:int main (void) | |
| 488 \& function main called 1 returned 1 blocks executed 75% | |
| 489 \& 1: 4:{ | |
| 490 \& 1: 5: int i, total; | |
| 491 \& \-: 6: | |
| 492 \& 1: 7: total = 0; | |
| 493 \& \-: 8: | |
| 494 \& 11: 9: for (i = 0; i < 10; i++) | |
| 495 \& branch 0 taken 91% (fallthrough) | |
| 496 \& branch 1 taken 9% | |
| 497 \& 10: 10: total += i; | |
| 498 \& \-: 11: | |
| 499 \& 1: 12: if (total != 45) | |
| 500 \& branch 0 taken 0% (fallthrough) | |
| 501 \& branch 1 taken 100% | |
| 502 \& #####: 13: printf ("Failure\en"); | |
| 503 \& call 0 never executed | |
| 504 \& \-: 14: else | |
| 505 \& 1: 15: printf ("Success\en"); | |
| 506 \& call 0 called 1 returned 100% | |
| 507 \& 1: 16: return 0; | |
| 508 \& \-: 17:} | |
| 509 .Ve | |
| 510 .PP | |
| 511 For each function, a line is printed showing how many times the function | |
| 512 is called, how many times it returns and what percentage of the | |
| 513 function's blocks were executed. | |
| 514 .PP | |
| 515 For each basic block, a line is printed after the last line of the basic | |
| 516 block describing the branch or call that ends the basic block. There can | |
| 517 be multiple branches and calls listed for a single source line if there | |
| 518 are multiple basic blocks that end on that line. In this case, the | |
| 519 branches and calls are each given a number. There is no simple way to map | |
| 520 these branches and calls back to source constructs. In general, though, | |
| 521 the lowest numbered branch or call will correspond to the leftmost construct | |
| 522 on the source line. | |
| 523 .PP | |
| 524 For a branch, if it was executed at least once, then a percentage | |
| 525 indicating the number of times the branch was taken divided by the | |
| 526 number of times the branch was executed will be printed. Otherwise, the | |
| 527 message \*(L"never executed\*(R" is printed. | |
| 528 .PP | |
| 529 For a call, if it was executed at least once, then a percentage | |
| 530 indicating the number of times the call returned divided by the number | |
| 531 of times the call was executed will be printed. This will usually be | |
| 532 100%, but may be less for functions that call \f(CW\*(C`exit\*(C'\fR or \f(CW\*(C`longjmp\*(C'\fR, | |
| 533 and thus may not return every time they are called. | |
| 534 .PP | |
| 535 The execution counts are cumulative. If the example program were | |
| 536 executed again without removing the \fI.gcda\fR file, the count for the | |
| 537 number of times each line in the source was executed would be added to | |
| 538 the results of the previous run(s). This is potentially useful in | |
| 539 several ways. For example, it could be used to accumulate data over a | |
| 540 number of program runs as part of a test verification suite, or to | |
| 541 provide more accurate long-term information over a large number of | |
| 542 program runs. | |
| 543 .PP | |
| 544 The data in the \fI.gcda\fR files is saved immediately before the program | |
| 545 exits. For each source file compiled with \fB\-fprofile\-arcs\fR, the | |
| 546 profiling code first attempts to read in an existing \fI.gcda\fR file; if | |
| 547 the file doesn't match the executable (differing number of basic block | |
| 548 counts) it will ignore the contents of the file. It then adds in the | |
| 549 new execution counts and finally writes the data to the file. | |
| 550 .Sh "Using \fBgcov\fP with \s-1GCC\s0 Optimization" | |
| 551 .IX Subsection "Using gcov with GCC Optimization" | |
| 552 If you plan to use \fBgcov\fR to help optimize your code, you must | |
| 553 first compile your program with two special \s-1GCC\s0 options: | |
| 554 \&\fB\-fprofile\-arcs \-ftest\-coverage\fR. Aside from that, you can use any | |
| 555 other \s-1GCC\s0 options; but if you want to prove that every single line | |
| 556 in your program was executed, you should not compile with optimization | |
| 557 at the same time. On some machines the optimizer can eliminate some | |
| 558 simple code lines by combining them with other lines. For example, code | |
| 559 like this: | |
| 560 .PP | |
| 561 .Vb 4 | |
| 562 \& if (a != b) | |
| 563 \& c = 1; | |
| 564 \& else | |
| 565 \& c = 0; | |
| 566 .Ve | |
| 567 .PP | |
| 568 can be compiled into one instruction on some machines. In this case, | |
| 569 there is no way for \fBgcov\fR to calculate separate execution counts | |
| 570 for each line because there isn't separate code for each line. Hence | |
| 571 the \fBgcov\fR output looks like this if you compiled the program with | |
| 572 optimization: | |
| 573 .PP | |
| 574 .Vb 4 | |
| 575 \& 100: 12:if (a != b) | |
| 576 \& 100: 13: c = 1; | |
| 577 \& 100: 14:else | |
| 578 \& 100: 15: c = 0; | |
| 579 .Ve | |
| 580 .PP | |
| 581 The output shows that this block of code, combined by optimization, | |
| 582 executed 100 times. In one sense this result is correct, because there | |
| 583 was only one instruction representing all four of these lines. However, | |
| 584 the output does not indicate how many times the result was 0 and how | |
| 585 many times the result was 1. | |
| 586 .PP | |
| 587 Inlineable functions can create unexpected line counts. Line counts are | |
| 588 shown for the source code of the inlineable function, but what is shown | |
| 589 depends on where the function is inlined, or if it is not inlined at all. | |
| 590 .PP | |
| 591 If the function is not inlined, the compiler must emit an out of line | |
| 592 copy of the function, in any object file that needs it. If | |
| 593 \&\fIfileA.o\fR and \fIfileB.o\fR both contain out of line bodies of a | |
| 594 particular inlineable function, they will also both contain coverage | |
| 595 counts for that function. When \fIfileA.o\fR and \fIfileB.o\fR are | |
| 596 linked together, the linker will, on many systems, select one of those | |
| 597 out of line bodies for all calls to that function, and remove or ignore | |
| 598 the other. Unfortunately, it will not remove the coverage counters for | |
| 599 the unused function body. Hence when instrumented, all but one use of | |
| 600 that function will show zero counts. | |
| 601 .PP | |
| 602 If the function is inlined in several places, the block structure in | |
| 603 each location might not be the same. For instance, a condition might | |
| 604 now be calculable at compile time in some instances. Because the | |
| 605 coverage of all the uses of the inline function will be shown for the | |
| 606 same source lines, the line counts themselves might seem inconsistent. | |
| 607 .SH "SEE ALSO" | |
| 608 .IX Header "SEE ALSO" | |
| 609 \&\fIgpl\fR\|(7), \fIgfdl\fR\|(7), \fIfsf\-funding\fR\|(7), \fIgcc\fR\|(1) and the Info entry for \fIgcc\fR. | |
| 610 .SH "COPYRIGHT" | |
| 611 .IX Header "COPYRIGHT" | |
| 612 Copyright (c) 1996, 1997, 1999, 2000, 2001, 2002, 2003, 2004, 2005, | |
| 613 2008 Free Software Foundation, Inc. | |
| 614 .PP | |
| 615 Permission is granted to copy, distribute and/or modify this document | |
| 616 under the terms of the \s-1GNU\s0 Free Documentation License, Version 1.2 or | |
| 617 any later version published by the Free Software Foundation; with the | |
| 618 Invariant Sections being \*(L"\s-1GNU\s0 General Public License\*(R" and \*(L"Funding | |
| 619 Free Software\*(R", the Front-Cover texts being (a) (see below), and with | |
| 620 the Back-Cover Texts being (b) (see below). A copy of the license is | |
| 621 included in the \fIgfdl\fR\|(7) man page. | |
| 622 .PP | |
| 623 (a) The \s-1FSF\s0's Front-Cover Text is: | |
| 624 .PP | |
| 625 .Vb 1 | |
| 626 \& A GNU Manual | |
| 627 .Ve | |
| 628 .PP | |
| 629 (b) The \s-1FSF\s0's Back-Cover Text is: | |
| 630 .PP | |
| 631 .Vb 3 | |
| 632 \& You have freedom to copy and modify this GNU Manual, like GNU | |
| 633 \& software. Copies published by the Free Software Foundation raise | |
| 634 \& funds for GNU development. | |
| 635 .Ve |