So far CSA was relying on the LLVM Statistic package that allowed us to
gather some data about analysis of an entire translation unit. However,
the translation unit consists of a collection of loosely related entry
points. Aggregating data across multiple such entry points is often
counter productive.
This change introduces a new lightweight always-on facility to collect
Boolean or numerical statistics for each entry point and dump them in a
CSV format. Such format makes it easy to aggregate data across multiple
translation units and analyze it with common data-processing tools.
We break down the existing statistics that were collected on the per-TU
basis into values per entry point.
Additionally, we enable the statistics unconditionally (STATISTIC ->
ALWAYS_ENABLED_STATISTIC) to facilitate their use (you can gather the
data with a simple run-time flag rather than having to recompile the
analyzer). These statistics are very light and add virtually no
overhead.
Co-authored-by: Balazs Benics <benicsbalazs@gmail.com>
CPP-6160
