Introduction to gcov-tool
gcov-tool is an offline tool to process gccs gcda profile files.
Current gcov-tool supports the following functionalities:
merge two sets of profiles with weights.
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.
the consistency of the summary and the histogram.
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.
depends on the link list order of gcov-info objects. This order is different in gcov-tool from that in the online merge. Its expected to have different summary checksums. It does not really matter as the compiler does not use this checksum anywhere.
are runtime dependent, like heap addresses. Its normal to see some difference in these kind of counters.