gcov-tool - offline gcda profile processing tool
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]
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.
- -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.
- rewrite
- Read the specified profile directory and rewrite to a new directory.
- 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.
gpl(7), gfdl(7), fsf-funding(7),
gcc(1), gcov(1) and the Info entry for gcc.
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