tree 9a66b0192d9049d16956218ca3bafc65af1de63f
parent bbf3e421ed8b2b431a72cd3ab4ba591dc8833634
author elenairina <elenairina@google.com> 1528730741 -0700
committer Copybara-Service <copybara-piper@google.com> 1528730842 -0700

Implement LcovMerger.

LcovMerger is a tool that merges all the intermediate lcov tracefiles (with .dat extension) found under a coverage directory and prints the merged tracefile to a given output file.

A custom implementation for merging lcov tracefiles is needed because the merging functionality of lcov itself is very slow.

LcovMerger is required to get a single coverage report (lcov tracefile) from a bazel coverage command that executes multiple tests.

ATM LcovMerger is only invoked by tools/test/collect_coverage.sh that collects and merges the tracefiles from a single test invocation. It will also be used from a CoverageReportAction.

Progress on #5246.

PiperOrigin-RevId: 200054506