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