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lcov

NAME

lcov - GCOV coverage tool extension

SYNOPSIS

lcov [-h|--help] [-v|--version] [-q|--quiet]

[-z|--zerocounters] [-c|--capture]
[-a|--add-tracefile tracefile]
[-e|--extract tracefile]
[-r|--remove tracefile]
[-l|--list tracefile]
[--diff tracefile diff]
[-i|--initial] [-t|--test-name testname]
[-o|--output-file filename]
[-d|--directory directory]
[-f|--follow]
[-k|--kernel-directory directory]
[-b|--base-directory directory]
[--convert-filenames] [--strip depth] [--path path]
[--checksum] [--no-checksum]
[--compat-libtool] [--no-compat-libtool]
[--gcov-tool tool] [--ignore-errors errors]

DESCRIPTION

lcov is an extension of GCOV, a GNU tool which provides information about what parts of a program are actually executed (i.e. "covered") during a particular test case. The extension consists of a set of PERL scripts which build on the textual GCOV output to implement HTML output and support for large projects.

Use lcov to collect coverage data from either the currently running Linux kernel or from a user space application. To do this, you have to complete the following preparation steps:

For Linux kernel coverage:

Download and install the "gcov-kernel" package from http://sourceforge.net/projects/ltp
The resulting kernel module has to be installed either in the system wide kernel modules directory or in the same directory as the LCOV tool. Note that you will need root privileges to access kernel coverage data.

For user space application coverage:

Compile the application with GCC using the options "-fprofile-arcs" and "-ftest-coverage".

Please note that this man page refers to the output format of lcov as ".info file" or "tracefile" and that the output of GCOV is called ".da file".

OPTIONS

-a tracefile
--add-tracefile tracefile

Add contents of tracefile.
Specify several tracefiles using the -a switch to combine the coverage data contained in these files by adding up execution counts for matching test and filename combinations.
The result of the add operation will be written to stdout or the tracefile specified with -o.
Only one of -z, -c, -a, -e, -r, -l and --diff may be specified at a time.

-b directory
--base-directory directory

Use directory as base directory for relative paths.
Use this option to specify the base directory of a build-environment when lcov produces error messages like:

ERROR: could not read source file /home/user/project/subdir1/subdir2/subdir1/subdir2/file.c

In this example, use /home/user/project as base directory.

This option is required when using lcov on projects built with libtool or similar build environments that work with a base directory, i.e. environments, where the current working directory when invoking the compiler is not the same directory in which the source code file is located.

Note that this option will not work in environments where multiple base directories are used. In that case repeat the lcov call for each base directory while using the --ignore-errors option to prevent lcov from exiting when the first source code file could not be found. This way you can get partial coverage information for each base directory which can then be combined using the -a option.

-c
--capture

Capture coverage data.
By default captures the current kernel execution counts and writes the resulting coverage data to the standard output. Use the --directory option to capture counts for a user space program.
The result of the capture operation will be written to stdout or the tracefile specified with -o.
Only one of -z, -c, -a, -e, -r, -l and --diff may be specified at a time.

--checksum
--no-checksum

Specify whether to generate checksum data when writing tracefiles.
Use --checksum to enable checksum generation or --no-checksum to disable it. Checksum generation is disabled by default.
When checksum generation is enabled, a checksum will be generated for each source code line and stored along with the coverage data. This checksum will be used to prevent attempts to combine coverage data from different source code versions.
If you don't work with different source code versions, disable this option to speed up coverage data processing and to reduce the size of tracefiles.

--compat-libtool
--no-compat-libtool

Specify whether to enable libtool compatibility mode.
Use --compat-libtool to enable libtool compatibility mode or --no-compat-libtool to disable it. The libtool compatibility mode is enabled by default.
When libtool compatibility mode is enabled, lcov will assume that the source code relating to a .da file located in a directory named ".libs" can be found in its parent directory.
If you have directories named ".libs" in your build environment but don't use libtool, disable this option to prevent problems when capturing coverage data.

--convert-filenames

Convert filenames when applying diff.
Use this option together with --diff to rename the file names of processed data sets according to the data provided by the diff.

--diff tracefile difffile

Convert coverage data in tracefile using source code diff file difffile.
Use this option if you want to merge coverage data from different source code levels of a program, e.g. when you have data taken from an older version and want to combine it with data from a more current version. lcov will try to map source code lines between those versions and adjust the coverage data respectively. difffile needs to be in unified format, i.e. it has to be created using the "-u" option of the diff tool.
Note that lines which are not present in the old version will not be counted as instrumented, therefore tracefiles resulting from this operation should not be interpreted individually but together with other tracefiles taken from the newer version. Also keep in mind that converted coverage data should only be used for overview purposes as the process itself introduces a loss of accuracy.
The result of the diff operation will be written to stdout or the tracefile specified with -o.
Only one of -z, -c, -a, -e, -r, -l and --diff may be specified at a time.

-d directory
--directory directory

Use .da files in directory instead of kernel.
If you want to work on coverage data for a user space program, use this option to specify the location where the program was compiled (that's where the counter files ending with .da will be stored).
Note that you may specify this option more than once.

-e tracefile pattern
--extract tracefile pattern

Extract data from tracefile.
Use this switch if you want to extract coverage data for only a particular set of files from a tracefile. Additional command line parameters will be interpreted as shell wildcard patterns (note that they may need to be escaped accordingly to prevent the shell from expanding them first). Every file entry in tracefile which matches at least one of those patterns will be extracted.
The result of the extract operation will be written to stdout or the tracefile specified with -o.
Only one of -z, -c, -a, -e, -r, -l and --diff may be specified at a time.

-f
--follow

Follow links when searching for .da files.

--gcov-tool tool

Specify the location of the gcov tool.

-h
--help

Print a short help text, then exit.

--ignore-errors errors

Specify a list of errors after which to continue processing.
Use this option to specify a list of one or more classes of errors after which lcov should continue processing instead of aborting.
errors can be a comma-separated list of the following keywords:
gcov: the gcov tool returned with a non-zero return code.
source: the source code file for a data set could not be found.

-i
--initial

Capture initial zero coverage data.
Run lcov with -c and this option on the directories containing .bb, .bbg or .gcno files before running any test case. The result is a "baseline" coverage data file that contains zero coverage for every instrumented line. Combine this data file (using lcov -a) with coverage data files captured after a test run to ensure that the percentage of total lines covered is correct even when not all source code files were loaded during the test.
Recommended procedure when capturing data for a test case:
1. create baseline coverage data file

# lcov -c -i -d appdir -o app_base.info

2. perform test

# appdir/test

3. create test coverage data file

# lcov -c -d appdir -o app_test.info

4. combine baseline and test coverage data

# lcov -a app_base.info -a app_test.info -o app_total.info

-k subdirectory
--kernel-directory subdirectory

Capture kernel coverage data only from subdirectory.
Use this option if you don't want to get coverage data for all of the kernel, but only for specific subdirectories.
Note that you may specify this option more than once.

-l tracefile
--list tracefile

List the contents of the tracefile.
Only one of -z, -c, -a, -e, -r, -l and --diff may be specified at a time.

-o tracefile
--output-file tracefile

Write data to tracefile instead of stdout.
Specify "-" as a filename to use the standard output.
By convention, lcov-generated coverage data files are called "tracefiles" and should have the filename extension ".info".

--path path

Strip path from filenames when applying diff.
Use this option together with --diff to tell lcov to disregard the specified initial path component when matching between tracefile and diff filenames.

-q
--quiet

Do not print progress messages.
This option is implied when no output filename is specified to prevent progress messages to mess with coverage data which is also printed to the standard output.

-r tracefile pattern
--remove tracefile pattern

Remove data from tracefile.
Use this switch if you want to remove coverage data for a particular set of files from a tracefile. Additional command line parameters will be interpreted as shell wildcard patterns (note that they may need to be escaped accordingly to prevent the shell from expanding them first). Every file entry in tracefile which matches at least one of those patterns will be removed.
The result of the remove operation will be written to stdout or the tracefile specified with -o.
Only one of -z, -c, -a, -e, -r, -l and --diff may be specified at a time.

--strip depth

Strip path components when applying diff.
Use this option together with --diff to tell lcov to disregard the specified number of initial directories when matching tracefile and diff filenames.

-t testname
--test-name testname

Specify test name to be stored in the tracefile.
This name identifies a coverage data set when more than one data set is merged into a combined tracefile (see option -a).
Valid test names can consist of letters, decimal digits and the underscore character ("_").

-v
--version

Print version number, then exit.

-z
--zerocounters

Reset all execution counts to zero.
By default tries to reset kernel execution counts. Use the --directory option to reset all counters of a user space program.
Only one of -z, -c, -a, -e, -r, -l and --diff may be specified at a time.

FILES

/etc/lcovrc

The system-wide configuration file.

~/.lcovrc

The per-user configuration file.

AUTHOR

Peter Oberparleiter <Peter.Oberparleiter@de.ibm.com>

SEE ALSO

lcovrc(5), genhtml(1), geninfo(1), genpng(1), gendesc(1), gcov(1)