NAME

       llvm-cov - emit coverage information

SYNOPSIS

       llvm-cov [options] SOURCEFILE

DESCRIPTION

       The llvm-cov tool reads code coverage data files and displays the coverage information for
       a specified source file. It is compatible with the gcov tool from version 4.2 of  GCC  and
       may also be compatible with some later versions of gcov.

       To  use  llvm-cov,  you  must first build an instrumented version of your application that
       collects coverage data as it runs. Compile with  the  -fprofile-arcs  and  -ftest-coverage
       options  to  add  the  instrumentation. (Alternatively, you can use the --coverage option,
       which includes both of those other options.) You should compile with debugging information
       (-g)  and  without  optimization  (-O0); otherwise, the coverage data cannot be accurately
       mapped back to the source code.

       At the time you compile the instrumented code, a .gcno data file  will  be  generated  for
       each  object  file. These .gcno files contain half of the coverage data. The other half of
       the data comes from .gcda files that are generated when you run the instrumented  program,
       with  a  separate  .gcda  file  for  each  object file. Each time you run the program, the
       execution counts are summed into any existing .gcda files, so be sure to  remove  any  old
       files if you do not want their contents to be included.

       By  default,  the .gcda files are written into the same directory as the object files, but
       you can override  that  by  setting  the  GCOV_PREFIX  and  GCOV_PREFIX_STRIP  environment
       variables. The GCOV_PREFIX_STRIP variable specifies a number of directory components to be
       removed from the start of the absolute path to the object file directory. After  stripping
       those  directories,  the  prefix from the GCOV_PREFIX variable is added. These environment
       variables allow you to run the instrumented program on a machine where the original object
       file  directories  are not accessible, but you will then need to copy the .gcda files back
       to the object file directories where llvm-cov expects to find them.

       Once you have generated the coverage data files, run llvm-cov for each  main  source  file
       where you want to examine the coverage results. This should be run from the same directory
       where you previously ran the compiler. The results  for  the  specified  source  file  are
       written  to  a  file  named  by  appending  a .gcov suffix. A separate output file is also
       created for each file included by the main source file, also with a .gcov suffix added.

       The basic content of an llvm-cov output file  is  a  copy  of  the  source  file  with  an
       execution count and line number prepended to every line. The execution count is shown as -
       if a line does not contain any executable code. If a line contains code but that code  was
       never executed, the count is displayed as #####.

OPTIONS

       -a, --all-blocks
              Display  all basic blocks. If there are multiple blocks for a single line of source
              code, this option causes llvm-cov to show the count for each block instead of  just
              one count for the entire line.

       -b, --branch-probabilities
              Display conditional branch probabilities and a summary of branch information.

       -c, --branch-counts
              Display branch counts instead of probabilities (requires -b).

       -f, --function-summaries
              Show  a  summary  of  coverage for each function instead of just one summary for an
              entire source file.

       --help Display available options (--help-hidden for more).

       -l, --long-file-names
              For coverage output of files included from the main source file, add the main  file
              name followed by ## as a prefix to the output file names. This can be combined with
              the --preserve-paths option to use complete paths for both the main  file  and  the
              included file.

       -n, --no-output
              Do not output any .gcov files. Summary information is still displayed.

       -o=<DIR|FILE>, --object-directory=<DIR>, --object-file=<FILE>
              Find  objects  in  DIR  or based on FILE's path. If you specify a particular object
              file, the coverage data files are expected to have the same base  name  with  .gcno
              and  .gcda  extensions.  If you specify a directory, the files are expected in that
              directory with the same base name as the source file.

       -p, --preserve-paths
              Preserve path components when naming the coverage output files. In addition to  the
              source  file  name,  include  the  directories  from  the  path  to  that file. The
              directories are separate by  #  characters,  with  .  directories  removed  and  ..
              directories  replaced by ^ characters. When used with the --long-file-names option,
              this applies to both the main file name and the included file name.

       -u, --unconditional-branches
              Include unconditional branches in the output for the --branch-probabilities option.

       -version
              Display the version of llvm-cov.

EXIT STATUS

       llvm-cov returns 1 if it cannot read input files.  Otherwise, it exits with zero.

AUTHOR

       Maintained by The LLVM Team (http://llvm.org/).

COPYRIGHT

       2003-2014, LLVM Project