Provided by: llvm-3.6_3.6.2-3ubuntu2_amd64 
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