Function parse_address_map

crates/environ/src/address_map.rs:146–158

Parse an `ELF_WASMTIME_ADDRMAP` section, returning the slice of code offsets and the slice of associated file positions for each offset.

(section: &[u8])

/// Parse an `ELF_WASMTIME_ADDRMAP` section, returning the slice of code offsets
/// and the slice of associated file positions for each offset.
fn parse_address_map(section: &[u8]) -> Option<(&[U32<LittleEndian>], &[U32<LittleEndian>])> {
    let mut section = Bytes(section);
    // NB: this matches the encoding written by `append_to` in the
    // `compile::address_map` module.
    let count = section.read::<U32<LittleEndian>>().ok()?;
    let count = usize::try_from(count.get(LittleEndian)).ok()?;
    let (offsets, section) =
        object::slice_from_bytes::<U32<LittleEndian>>(section.0, count).ok()?;
    let (positions, section) =
        object::slice_from_bytes::<U32<LittleEndian>>(section, count).ok()?;
    debug_assert!(section.is_empty());
    Some((offsets, positions))
}

/// Lookup an `offset` within an encoded address map section, returning the
/// original `FilePos` that corresponds to the offset, if found.