m2lang - The LLVM-based Modula-2 compiler
Introduction
See this FOSDEM 2019 talk for some details.
Implementation decisions
- LLVM is only external dependency
- CMake scripts derived from clang
- ISO Modula-2 language first
- Use "declare-before-use" (single-pass) model
- Goal is target several platforms from the beginning
Current status
- The lexer is done.
- The preprocessor (for handling of directives) is is based on the draft technical report "Interfacing Modula-2 to C", Annex B and aims to be compatible to the Macintosh p1 compiler. Parsing of directives is implemented, with mostly no functionality.
- The parser is based on ISO Modula-2 with generic and OO additions. Some LL(1) conflicts are still left in the grammar, so not every source is parsed correctly.
- The parser is generated by LLtool. A C++ port of LLtool is now integrated into this project, but not yet enabled.
- Error recovery in the parser is based on "panic mode", using the follow sets of the current and the active callers.
- The AST nodes are generated by ASTtool.
- Error messages are outputted using llvm::SourceMgr for nice presentation.
- Only a dummy driver exists to see the parser in action.
- A couple of IR statements is emitted to the console after succesful parsing.