I recently migrated a project from Java to C++. I built the C++ runtime with Visual Studio Community 2019 which I also use for everything else in the C++ project. All my tests passes which shows that the parsing itself works the same for both targets.

The actual parsing for C++ is about 5x slower than Java even though the C++ code is built with release configuration optimized for speed and Java is executed in Eclipse debug mode!

The files parsed in the tests are about 500k. I can provide the grammar and data to parse if needed.

Anyone with a clue on why and what can be done?