Function is_obj_ptr_param

crates/cranelift/src/debug/transform/attr.rs:317–346

(
    entry: &gimli::write::ConvertUnitEntry<Reader<'_>>,
    param_num: isize,
)

}

fn is_obj_ptr_param(
    entry: &gimli::write::ConvertUnitEntry<Reader<'_>>,
    param_num: isize,
) -> Result<bool, Error> {
    debug_assert_eq!(entry.tag, gimli::DW_TAG_formal_parameter);
    let unit = entry.read_unit;

    // This logic was taken loosely from LLDB. It is known
    // that it is not fully correct (doesn't handle 'deduced
    // this', for example).
    // Q: DWARF includes DW_AT_object_pointer as we use it,
    // why do we need this heuristic as well?
    // A: Declarations do not include DW_AT_object_pointer.
    if param_num == 0
        && entry.attr_value(gimli::DW_AT_artificial) == Some(AttributeValue::Flag(true))
    {
        // Either this has no name (declarations omit them), or its explicitly "this".
        let name = entry.attr_value(gimli::DW_AT_name);
        if name.is_none() || unit.attr_string(name.unwrap())?.slice().eq(b"this") {
            // Finally, a type check. We expect a pointer.
            if let Some(type_attr) = entry.attr_value(gimli::DW_AT_type) {
                if let Some(type_die) = resolve_die_ref(unit, &type_attr)? {
                    return Ok(type_die.tag == gimli::DW_TAG_pointer_type);
                }
            }
        }
    };

    return Ok(false);
}