Module hostcall_trace_jit 

Tier-2 trace-JIT compiler for stabilized superinstruction plans.

Compiles high-confidence hostcall superinstruction traces into guarded native dispatch stubs, removing residual interpreter overhead while preserving deterministic fallback to the sequential dispatch path.

Architecture

The JIT tier sits above the superinstruction compiler:

Tier 0: Interpreter (sequential dispatch via match)
Tier 1: Superinstruction fusion (plan-based dispatch, see hostcall_superinstructions.rs)
Tier 2: Trace-JIT (pre-compiled dispatch tables with guard stubs) ← this module

A plan is promoted to JIT when it reaches a configurable hotness threshold (min_jit_executions). The compiled trace holds a guard sequence that is checked at entry; on guard failure the trace deoptimizes and falls back to tier-0 sequential dispatch.

Structs

CompiledTrace

A compiled trace stub with guard conditions and dispatch metadata.

GuardContext

Context supplied to guard checks.

JitExecutionResult

Result of attempting to execute via JIT.

TraceJitCompiler

Tier-2 trace-JIT compiler and dispatch cache.

TraceJitConfig

Configuration for the trace-JIT compiler tier.

TraceJitTelemetry

Snapshot of JIT compiler telemetry.

Enums

CompilationTier

Compilation tier for a trace.

DeoptReason

Reason why a JIT-compiled trace deoptimized.

TraceGuard

A guard condition that must hold for a compiled trace to execute.

Functions

estimated_jit_cost

Estimated JIT dispatch cost for a given opcode window width.