@chiragramani first of all, thank you for the detailed measurements and the reproducible test codes. We are aware of the performance issues regarding macros. And we, including myself, are actively working on it. There are a number key points we are looking at, including but not limited to:
- swift-syntax build time
- swift-syntax compiler side performance
- Plugin process startup overhead
- Message coding and serialization between the compiler and plugins
- Syntax tree visitation/mutation