hakorune/docs/reference/mir/MIR15_COVERAGE_CHECKLIST.md

MIR Core (~15) Coverage Checklist

Goal: Verify that the core MIR set executes correctly across VM and JIT (exe), then proceed to LLVM.

Target instructions (representative core):

• Basics: Const, UnaryOp, BinOp, Compare, TypeOp
• Memory: Load, Store
• Control: Branch, Jump, Return, Phi
• Box: NewBox, BoxCall, PluginInvoke
• Arrays: ArrayGet, ArraySet
• External: ExternCall

How to verify

• VM path

  • Run representative examples or unit snippets via --backend vm.
  • Enable VM stats for visibility: NYASH_VM_STATS=1

• JIT (compiler-only, exe emission where applicable)

  • Enable JIT compile path and hostcall: NYASH_JIT_EXEC=1 NYASH_JIT_THRESHOLD=1 NYASH_JIT_HOSTCALL=1
  • For PHI minimal path tests: NYASH_JIT_PHI_MIN=1
  • Optional DOT/trace: NYASH_JIT_DUMP=1 and/or NYASH_JIT_EVENTS_COMPILE=1

Quick smoke

• Build: cargo build --release --features cranelift-jit
• Run: tools/mir15_smoke.sh release
• Policy: Core-1 is required green; hostcall-based cases are optional (fallback allowed).

Suggested minimal scenarios

• Const/Return: function returns 0/1/42.
• BinOp/Compare: arithmetic and boolean conditions.
• Branch/Jump/Phi: single-diamond if/else with merging value.
• Load/Store: local slot store → load (VM) and JIT local slots (lower/core) coverage.
• TypeOp: is/as via builder emits TypeOp.
• NewBox/BoxCall: call basic methods (e.g., StringBox.length, IntegerBox.get via PluginInvoke where applicable).
• PluginInvoke/by-name: nyash.handle.of + invoke name path.
• Arrays: len/get/set/push hostcalls (JIT: handle-based externs wired).
• ExternCall: env.console.log, env.debug.trace, env.runtime.checkpoint.

Notes

• Debug/Safepoint/Future/Await are rewritable via env toggles; core stays focused on the above.
• JIT direct path is read-only; mutating ops should fallback or be whitelisted accordingly.

Once coverage is green on VM and JIT, proceed to LLVM feature work (inkwell-backed) following docs in execution-backends.