Struct TraceMetadata 

pub struct TraceMetadata {
    pub chunk_op_hash: u64,
    pub anchor_ip: usize,
    pub fallthrough_ip: usize,
    pub ops: Vec<Op>,
    pub recorded_ips: Vec<usize>,
    pub slot_kinds_at_anchor: Vec<SlotKind>,
}

Serializable trace metadata for persistent cache export/import (phase 7).

Captures everything needed to re-compile a previously-installed trace in a fresh process: the original recorded op sequence, the parallel bytecode IPs, the slot-type entry guard, and the fallthrough IP. Bind to the chunk via chunk_op_hash so a stale metadata file (chunk has changed) is rejected on import rather than silently mis-compiled.

Persistence format is intentionally serde-based so callers can pick whatever encoding fits their environment (JSON, bincode, custom binary). fusevm itself doesn’t ship a file format — JitCompiler::export_trace returns the struct, import_trace consumes one. The user owns I/O.

Fields

chunk_op_hash: u64

Hash of the chunk’s ops + constants pool at trace-record time. Used to detect chunk drift on import: a mismatched hash means the bytecode has changed and the persisted trace is stale.

anchor_ip: usize

Bytecode IP where the trace was anchored (the backward-branch header that crossed TRACE_THRESHOLD).

fallthrough_ip: usize

Bytecode IP the interpreter should resume at after the trace runs to completion (one past the loop’s natural exit).

ops: Vec<Op>

The captured op sequence in record order; the trace is a straight-line projection of these ops with side-exit guards inserted at each branch.

recorded_ips: Vec<usize>

Parallel array to ops: the original bytecode IP each recorded op corresponds to. Used to materialise the interpreter’s IP on deopt so execution resumes at the right place.

slot_kinds_at_anchor: Vec<SlotKind>

Slot type fingerprint at the entry guard. The trace’s entry stub compares each slot’s runtime type against this snapshot; mismatch → skip the trace and let the interpreter handle the iteration.

Trait Implementations

impl Clone for TraceMetadata

fn clone(&self) -> TraceMetadata

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TraceMetadata

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for TraceMetadata

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for TraceMetadata

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.