readDebugAddr

fn readDebugAddr(di: Dwarf, endian: Endian, compile_unit: *const CompileUnit, index: u64) !u64 {
    const debug_addr = di.section(.debug_addr) orelse return bad();

    // addr_base points to the first item after the header, however we
    // need to read the header to know the size of each item. Empirically,
    // it may disagree with is_64 on the compile unit.
    // The header is 8 or 12 bytes depending on is_64.
    if (compile_unit.addr_base < 8) return bad();

    const version = mem.readInt(u16, debug_addr[compile_unit.addr_base - 4 ..][0..2], endian);
    if (version != 5) return bad();

    const addr_size = debug_addr[compile_unit.addr_base - 2];
    const seg_size = debug_addr[compile_unit.addr_base - 1];

    const byte_offset = compile_unit.addr_base + (addr_size + seg_size) * index;
    if (byte_offset + addr_size > debug_addr.len) return bad();
    return switch (addr_size) {
        1 => debug_addr[@intCast(byte_offset)],
        2 => mem.readInt(u16, debug_addr[@intCast(byte_offset)..][0..2], endian),
        4 => mem.readInt(u32, debug_addr[@intCast(byte_offset)..][0..4], endian),
        8 => mem.readInt(u64, debug_addr[@intCast(byte_offset)..][0..8], endian),
        else => bad(),
    };
}