Ahead-of-Time Compilation

Baedeker can serialize a lowered module to an ahead-of-time (AOT) artifact, skipping decode + validate + lower at load time. This is useful for embedded targets where startup cost matters or where carrying a validator is unnecessary.

The artifact format

An AOT artifact is a postcard-serialized RegModule wrapped in a small envelope:

BDKAOT1  magic (7 bytes)
< u32 >  version
< postcard-encoded RegModule >

The aot feature (baedeker-core’s aot = serde + postcard) enables serialization and deserialization.

Compile

baedeker compile path/to/module.wasm -o module.bdkaot

The CLI decodes, validates, lowers, and writes the envelope. Or, in code:

#![allow(unused)]
fn main() {
use baedeker_core::binary::module::Module;
use baedeker_core::lower::lower_module;
use baedeker_core::aot;
fn go(bytes: &[u8]) {
let reg = lower_module(&Module::decode(bytes).unwrap()).unwrap();
let artifact = aot::serialize(&reg);
}
}

Load

#![allow(unused)]
fn main() {
use baedeker_core::runtime::{Store, execute_export, Value};
use baedeker_core::aot;
fn go(artifact: &[u8]) {
let reg = aot::deserialize(artifact).expect("valid artifact");
let store = Store::instantiate(&reg).unwrap();
let _ = execute_export(&reg, &store, "add", &[Value::I32(1), Value::I32(2)]);
}
}

Deserialization skips validation — the artifact is trusted. The FFI mirrors this with baedeker_module_from_aot.

Version-locking

AOT artifacts are version-locked: the magic and version prefix let a loader reject artifacts from an incompatible Baedeker version rather than misinterpreting them. Regenerate artifacts when bumping the IR.