Function aot_cache_key 

pub fn aot_cache_key(rust_source: &str) -> String

The cache key for an AOT-native artifact (HOTSWAP §Axis-3 / P16): a deterministic FNV-1a hash of the rustc toolchain version AND the optimized Rust source. The toolchain is in the key because Rust has no stable cross-version ABI — a different rustc/runtime yields a different key, so a stale, ABI-mismatched .so is NEVER reused (soundness over convenience). The source captures the function, its callees, and the optimization config (it IS the codegen output).