# gcov-tool

## 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 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 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
               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.
    
           **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.
    


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