# man > GCOV-TOOL(1)

[_GCOV-TOOL_(1)](https://www.chedong.com/phpMan.php/man/GCOV-TOOL/1/markdown)                                     GNU                                    [_GCOV-TOOL_(1)](https://www.chedong.com/phpMan.php/man/GCOV-TOOL/1/markdown)

## NAME
       gcov-tool - offline gcda profile processing tool

## SYNOPSIS
       gcov-tool [**-v**|**--version**] [**-h**|**--help**]

       gcov-tool merge [merge-options] _directory1_ _directory2_
            [**-o**|**--output _**directory_]
            [**-v**|**--verbose**]
            [**-w**|**--weight _**w1,w2_]

       gcov-tool merge-stream [merge-stream-options] [_file_]
            [**-v**|**--verbose**]
            [**-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_]
            [**-v**|**--verbose**]

       gcov-tool overlap [overlap-options] _directory1_ _directory2_
            [**-f**|**--function**]
            [**-F**|**--fullname**]
            [**-h**|**--hotonly**]
            [**-o**|**--object**]
            [**-t**|**--hot_threshold**] _float_
            [**-v**|**--verbose**]

## DESCRIPTION
       **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  a  stream of profiles with associated filenames and merge it with a set 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.

       *   Collect profiles from target systems without a  filesystem  (freestanding  environments).
           Merge  the  collected  profiles with associated profiles present on the host system.  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 histogram.

       *   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
           approximation.

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

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

### merge
           Merge two profile directories.

           **-o _**directory_
           **--output _**directory_
               Set the output profile directory. Default output directory name is _merged_profile_.

           **-v**
           **--verbose**
               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.

### merge-stream
           Collect profiles with associated filenames from a _gcfn_ and _gcda_ data  stream.   Read  the
           stream from the file specified by _file_ or from _stdin_.  Merge the profiles with associated
           profiles in the host filesystem.  Apply the optional weights while merging profiles.

           For  the  generation  of  a _gcfn_ and _gcda_ data stream on the target system, please have a
           look at the "__gcov_filename_to_gcfn()" and "__gcov_info_to_gcda()" functions declared in
           "#include <gcov.h>".

           **-v**
           **--verbose**
               Set the verbose mode.

           **-w _**w1_**,_**w2_
           **--weight _**w1_**,_**w2_
               Set the merge weights of the profiles from the _gcfn_ and  _gcda_  data  stream  and  the
               associated  profiles in the host filesystem, respectively.  The default weights are 1
               for both.

### rewrite
           Read the specified profile directory and rewrite to a new directory.

           **-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 _rewrite_profile_.

           **-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.

           **-v**
           **--verbose**
               Set the verbose mode.

### overlap
           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.

           **-f**
           **--function**
               Print function level overlap score.

           **-F**
           **--fullname**
               Print full gcda filename.

           **-h**
           **--hotonly**
               Only print info for hot objects/functions.

           **-o**
           **--object**
               Print object level overlap score.

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

           **-v**
           **--verbose**
               Set the verbose mode.

## SEE ALSO
       [**gpl**(7)](https://www.chedong.com/phpMan.php/man/gpl/7/markdown), [**gfdl**(7)](https://www.chedong.com/phpMan.php/man/gfdl/7/markdown), [**fsf-funding**(7)](https://www.chedong.com/phpMan.php/man/fsf-funding/7/markdown), [**gcc**(1)](https://www.chedong.com/phpMan.php/man/gcc/1/markdown), [**gcov**(1)](https://www.chedong.com/phpMan.php/man/gcov/1/markdown) and the Info entry for _gcc_.

## COPYRIGHT
       Copyright (c) 2014-2023 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)](https://www.chedong.com/phpMan.php/man/gfdl/7/markdown) 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.

gcc-13.3.0                                   2024-05-21                                 [_GCOV-TOOL_(1)](https://www.chedong.com/phpMan.php/man/GCOV-TOOL/1/markdown)