README

Brief

This is a baseline stack VM with a naive JIT tier, using AsmJit and C++26. Maybe I'll add a dynamic language frontend later.

Usage

1. Ensure you have CMake 3.31+, a recent version of Clang supporting C++26, and AsmJit's entire source in deps/asmjit.
2. Enable ./project.sh.
3. Run ./project.sh build debug-build <your build tool>. The executable will be at path ./build/toyjit.

Design

• No concurrency in the JIT for simplicity.
• JITed native code pieces are called stubs.
  • Helper natives must interface with the VM / JIT via the same signature below, but hidden behind void*.
  • All these stubs must interface with the VM via using StubFn = Value(*)(VMState* vm, Value* locals, const Value* cvp, const void* helpers).
  • All stubs return a Value via rax back to their VM / native caller.
  • RDI: vm points to the VM context which can be used by any native functions passed in helpers for complex operations.
  • RSI: locals points to the 1st local slot just above the saved RIP and RBP natively...
  • RDX: cvp points to the 1st chunk constant and more...
  • RCX: helpers points to the 1st native helper or more...
  • Stubs emulate temporary value computations of the VM stack on the native stack for simplicity.
  • Scratch regs used: r8, r9, r10, r11
• Singly pass over a view of a hot bytecode chunk to compile a native code stub.
• Native code stubs are trampolined. Trampolines are short bytecode chunks that have {NATIVE_CALL <JIT-stub-ID>, RET}, {<no constants>}.