GCOV-TOOL(1)                         GNU                        GCOV-TOOL(1)

NAME         top

       gcov-tool - offline gcda profile processing tool

SYNOPSIS         top

       gcov-tool [-v|--version] [-h|--help]

       gcov-tool merge [merge-options] directory1 directory2
            [-o|--output directory]
            [-w|--weight w1,w2]

       gcov-tool rewrite [rewrite-options] directory
            [-n|--normalize long_long_value]
            [-o|--output directory]
            [-s|--scale float_or_simple-frac_value]

       gcov-tool overlap [overlap-options] directory1 directory2
            [-t|--hot_threshold] float

DESCRIPTION         top

       gcov-tool is an offline tool to process gcc's gcda profile files.

       Current gcov-tool supports the following functionalities:

       *   merge two sets of profiles with weights.

       *   read one set of profile and rewrite profile contents. One can
           scale or normalize the count values.

       Examples of the use cases for this tool are:

       *   Collect the profiles for different set of inputs, and use this
           tool to merge them. One can specify the weight to factor in the
           relative importance of each input.

       *   Rewrite the profile after removing a subset of the gcda files,
           while maintaining the consistency of the summary and the

       *   It can also be used to debug or libgcov code as the tools shares
           the majority code as the runtime library.

       Note that for the merging operation, this profile generated offline
       may contain slight different values from the online merged profile.
       Here are a list of typical differences:

       *   histogram difference: This offline tool recomputes the histogram
           after merging the counters. The resulting histogram, therefore,
           is precise. The online merging does not have this capability --
           the histogram is merged from two histograms and the result is an

       *   summary checksum difference: Summary checksum uses a CRC32
           operation. The value depends on the link list order of gcov-info
           objects. This order is different in gcov-tool from that in the
           online merge. It's expected to have different summary checksums.
           It does not really matter as the compiler does not use this
           checksum anywhere.

       *   value profile counter values difference: Some counter values for
           value profile are runtime dependent, like heap addresses. It's
           normal to see some difference in these kind of counters.

OPTIONS         top

           Display help about using gcov-tool (on the standard output), and
           exit without doing any further processing.

           Display the gcov-tool version number (on the standard output),
           and exit without doing any further processing.

           Merge two profile directories.

           -o directory
           --output directory
               Set the output profile directory. Default output directory
               name is merged_profile.

               Set the verbose mode.

           -w w1,w2
           --weight w1,w2
               Set the merge weights of the directory1 and directory2,
               respectively. The default weights are 1 for both.

           Read the specified profile directory and rewrite to a new

           -n long_long_value
           --normalize <long_long_value>
               Normalize the profile. The specified value is the max counter
               value in the new profile.

           -o directory
           --output directory
               Set the output profile directory. Default output name is

           -s float_or_simple-frac_value
           --scale float_or_simple-frac_value
               Scale the profile counters. The specified value can be in
               floating point value, or simple fraction value form, such 1,
               2, 2/3, and 5/3.

               Set the verbose mode.

           Compute the overlap score between the two specified profile
           directories.  The overlap score is computed based on the arc
           profiles. It is defined as the sum of min (p1_counter[i] /
           p1_sum_all, p2_counter[i] / p2_sum_all), for all arc counter i,
           where p1_counter[i] and p2_counter[i] are two matched counters
           and p1_sum_all and p2_sum_all are the sum of counter values in
           profile 1 and profile 2, respectively.

               Print function level overlap score.

               Print full gcda filename.

               Only print info for hot objects/functions.

               Print object level overlap score.

           -t float
           --hot_threshold <float>
               Set the threshold for hot counter value.

               Set the verbose mode.

SEE ALSO         top

       gpl(7), gfdl(7), fsf-funding(7), gcc(1), gcov(1) and the Info entry
       for gcc.

COPYRIGHT         top

       Copyright (c) 2014-2018 Free Software Foundation, Inc.

       Permission is granted to copy, distribute and/or modify this document
       under the terms of the GNU Free Documentation License, Version 1.3 or
       any later version published by the Free Software Foundation; with the
       Invariant Sections being "GNU General Public License" and "Funding
       Free Software", the Front-Cover texts being (a) (see below), and with
       the Back-Cover Texts being (b) (see below).  A copy of the license is
       included in the gfdl(7) man page.

       (a) The FSF's Front-Cover Text is:

            A GNU Manual

       (b) The FSF's Back-Cover Text is:

            You have freedom to copy and modify this GNU Manual, like GNU
            software.  Copies published by the Free Software Foundation raise
            funds for GNU development.

COLOPHON         top

       This page is part of the gcc (GNU Compiler Collection) project.
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       If you have a bug report for this manual page, see
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       If you discover any rendering problems in this HTML version of the
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       send a mail to

gcc-8.2.0                        2018-07-26                     GCOV-TOOL(1)