Struct WasmTier 

pub struct WasmTier { /* private fields */ }

The runtime WASM-JIT tier: per-function call counters plus a cache of compiled + instantiated modules. When a function crosses the hot threshold it is lowered to WASM and instantiated; subsequent calls dispatch to the compiled module. Functions the codegen declines are remembered as Ineligible and stay on the bytecode tier. The VM’s Op::Call consults this only under #[cfg(feature = "wasm-jit")], so the default build never carries it.

The host differs by target — and this is the whole point of the WASM backend:

• native: the pure-Rust [wasmi] interpreter. This is also the codegen oracle the differential tests cross-check the emitter against.
• wasm32: the platform’s real WebAssembly (V8 in the browser / node) via js_sys::WebAssembly. This is the production tier — a hot function tiers up to a freshly-compiled native WebAssembly module the host JITs, exactly as the spec requires.

on_call and the tier-up bookkeeping are target-independent; only [instantiate] and [ReadyModule::call] (the host seam) are #[cfg]-split.

Implementations

impl WasmTier

pub fn new(threshold: u32) -> Self

A tier that compiles a function after threshold calls (clamped to ≥1).

pub fn hits(&self) -> u64

How many calls have dispatched to a compiled WASM module — a diagnostic/test hook proving the tier actually fired.

pub fn on_call( &mut self, program: &CompiledProgram, func: u16, args: &[i64], ) -> Option<i64>

Run program.functions[func](args) on the WASM-JIT tier, or None to fall back to the bytecode tier (not yet hot, or ineligible). A Some result is the emitted module’s output — cross-checked against the VM by the differential tests.