### 11.2 Invoking `gcov-tool`

         gcov-tool [global-options] SUB_COMMAND [sub_command-options] profile_dir

`gcov-tool` accepts the following 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.
  `-v`
  `--verbose`
    Set the verbose mode.
  `-o` directory
  `--output` directory
    Set the output profile directory. Default output directory name is merged_profile.
  `-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.
  `-v`
  `--verbose`
    Set the verbose mode.
  `-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.
  `-n` long_long_value
  `--normalize <long_long_value>`
    Normalize the profile. The specified value is the max counter value in the new profile.
`overlap`
  Computer 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.
  `-v`
  `--verbose`
    Set the verbose mode.
  `-h`
  `--hotonly`
    Only print info for hot objects/functions.
  `-f`
  `--function`
    Print function level overlap score.
  `-F`
  `--fullname`
    Print full gcda filename.
  `-o`
  `--object`
    Print object level overlap score.
  `-t` float
  `--hot_threshold <float>`
    Set the threshold for hot counter value.