LLVM-COV(1) LLVM LLVM-COV(1)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 instrumenta‐
tion. (Alternatively, you can use the --coverage option, which includes
both of those other options.) You should compile with debugging infor‐
mation (-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 sepa‐
rate .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 acces‐
sible, 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 dis‐
played.
-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 instru‐
mentation 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 pro‐
file file, typically called default.profraw, which can be converted to
a format that is suitable for the PROFILE argument using the llvm-prof‐
data 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 inclu‐
sions, 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 archi‐
tecture to use. It is an error to specify an architecture that
is not included in the universal binary or to use an architec‐
ture 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 regu‐
lar expression.
-format=<FORMAT>
Use the specified output format. The supported formats are:
“text”, “html”.
-output-dir=PATH
Specify a directory to write coverage reports into. If the
directory does not exist, it is created. When used in function
view mode (i.e when -name or -name-regex are used to select spe‐
cific functions), the report is written to PATH/functions.EXTEN‐
SION. When used in file view mode, a report for each file is
written to PATH/REL_PATH_TO_FILE.EXTENSION.
-Xdemangler=<TOOL>|<TOOL-OPTION>
Specify a symbol demangler. This can be used to make reports
more human-readable. This option can be specified multiple times
to supply arguments to the demangler (e.g -Xdemangler c++filt
-Xdemangler-n for C++). The demangler is expected to read a
newline-separated list of symbols from stdin and write a new‐
line-separated list of the same length to stdout.
-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 fil‐
tered 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 pro‐
file 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 archi‐
tecture to use. It is an error to specify an architecture that
is not included in the universal binary or to use an architec‐
ture that does not match a non-universal binary.
AUTHOR
Maintained by The LLVM Team (http://llvm.org/).
COPYRIGHT
2003-2017, LLVM Project
3.9 2017-12-22 LLVM-COV(1)
