A Fast Bytecode VM for Arithmetic: The Compiler
16 days ago
- #Haskell
- #Virtual Machine
- #Bytecode
- The post discusses creating a fast bytecode compiler and virtual machine (VM) for arithmetic in Haskell.
- Bytecode is introduced as a compact, flattened representation of a program, optimized for execution by a VM, contrasting with AST interpreters which are slower due to memory jumping.
- The VM can be stack-based or register-based, with stack-based VMs being simpler to implement, hence chosen for this project.
- The compiler converts an expression AST to bytecode, with specific opcodes designed for numbers (OPush), binary operations (OAdd, OSub, OMul, ODiv), and variable handling (OGet, OSwapPop).
- Variables and let expressions are managed by tracking stack indices, ensuring the 'exactly-one-value' invariant after evaluation.
- Performance optimizations are detailed, including pre-allocating bytestrings for compilation, which significantly speeds up the process compared to using lists or other data structures.
- The post also covers the creation of a decompiler to convert bytecode back to a readable form, aiding in debugging and testing.
- Testing the compiler involves unit tests for both successful compilation and error cases, ensuring robustness.
- The series is part of a larger exploration into creating a fast bytecode VM for arithmetic, with future posts planned on the VM itself and benchmarking.