Provided by: llvm-3.8_3.8-2ubuntu3~trusty5_amd64 
NAME
llvm-cov - emit coverage information
SYNOPSIS
llvm-cov command [args...]
DESCRIPTION
The llvm-cov tool shows code coverage information for programs that are instrumented to
emit profile data. It can be used to work with gcov-style coverage or with clang's
instrumentation based profiling.
If the program is invoked with a base name of gcov, it will behave as if the llvm-cov gcov
command were called. Otherwise, a command should be provided.
COMMANDS
• gcov
• show
• report
GCOV COMMAND
SYNOPSIS
llvm-cov gcov [options] SOURCEFILE
DESCRIPTION
The llvm-cov gcov 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 gcov, 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 gcov expects to find them.
Once you have generated the coverage data files, run llvm-cov gcov 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 .gcov 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 gcov returns 1 if it cannot read input files. Otherwise, it exits with zero.
SHOW COMMAND
SYNOPSIS
llvm-cov show [options] -instr-profile PROFILE BIN [SOURCES]
DESCRIPTION
The llvm-cov show command shows line by line coverage of a binary BIN using the profile
data PROFILE. It can optionally be filtered to only show the coverage for the files listed
in SOURCES.
To use llvm-cov show, you need a program that is compiled with instrumentation to emit
profile and coverage data. To build such a program with clang use the
-fprofile-instr-generate and -fcoverage-mapping flags. If linking with the clang driver,
pass -fprofile-instr-generate to the link stage to make sure the necessary runtime
libraries are linked in.
The coverage information is stored in the built executable or library itself, and this is
what you should pass to llvm-cov show as the BIN argument. The profile data is generated
by running this instrumented program normally. When the program exits it will write out a
raw profile file, typically called default.profraw, which can be converted to a format
that is suitable for the PROFILE argument using the llvm-profdata merge tool.
OPTIONS
-show-line-counts
Show the execution counts for each line. This is enabled by default, unless another
-show option is used.
-show-expansions
Expand inclusions, such as preprocessor macros or textual inclusions, inline in the
display of the source file.
-show-instantiations
For source regions that are instantiated multiple times, such as templates in C++,
show each instantiation separately as well as the combined summary.
-show-regions
Show the execution counts for each region by displaying a caret that points to the
character where the region starts.
-show-line-counts-or-regions
Show the execution counts for each line if there is only one region on the line,
but show the individual regions if there are multiple on the line.
-use-color[=VALUE]
Enable or disable color output. By default this is autodetected.
-arch=<name>
If the covered binary is a universal binary, select the architecture to use. It is
an error to specify an architecture that is not included in the universal binary or
to use an architecture that does not match a non-universal binary.
-name=<NAME>
Show code coverage only for functions with the given name.
-name-regex=<PATTERN>
Show code coverage only for functions that match the given regular expression.
-line-coverage-gt=<N>
Show code coverage only for functions with line coverage greater than the given
threshold.
-line-coverage-lt=<N>
Show code coverage only for functions with line coverage less than the given
threshold.
-region-coverage-gt=<N>
Show code coverage only for functions with region coverage greater than the given
threshold.
-region-coverage-lt=<N>
Show code coverage only for functions with region coverage less than the given
threshold.
REPORT COMMAND
SYNOPSIS
llvm-cov report [options] -instr-profile PROFILE BIN [SOURCES]
DESCRIPTION
The llvm-cov report command displays a summary of the coverage of a binary BIN using the
profile data PROFILE. It can optionally be filtered to only show the coverage for the
files listed in SOURCES.
If no source files are provided, a summary line is printed for each file in the coverage
data. If any files are provided, summaries are shown for each function in the listed files
instead.
For information on compiling programs for coverage and generating profile data, see SHOW
COMMAND.
OPTIONS
-use-color[=VALUE]
Enable or disable color output. By default this is autodetected.
-arch=<name>
If the covered binary is a universal binary, select the architecture to use. It is
an error to specify an architecture that is not included in the universal binary or
to use an architecture that does not match a non-universal binary.
AUTHOR
Maintained by The LLVM Team (http://llvm.org/).
COPYRIGHT
2003-2017, LLVM Project