8149bb9d6a
Summary: In options_helper.cc various functions take a const unordered_map of string -> TypeInfo for options handling. These functions pass by-value the (const) maps, resulting in unnecessary copies. Change to pass by reference. This results in a noticable reduction in the amount of time spent parsing options - in my case a set of unit tests using RocksDB which call SetOptions() to modify options see a ~25% runtime reduction. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5295 Differential Revision: D15296334 Pulled By: riversand963 fbshipit-source-id: 4d4be3db635264943607911b296dda27fd7ce1a7