==========Example:
$ cat toy.cpp
#include <iostream>
int main() {
        std::cout << "hello world";
        return 0;
}
$ clang-14 -g -stdlib=libc++ -lc++ -I/usr/lib/llvm-14/include/c++/v1 toy.cpp -o toy14
$ addr2line -fe ./toy 0x1234
addr2line: DWARF error: invalid or unhandled FORM value: 0x25
main
??:?
=========end example

According to the dwarf5 spec (https://dwarfstd.org/doc/DWARF5.pdf), section 7.5.6 page 221, 0x25 is a valid DW_FORM value:

      DW_FORM_strx1 ‡ 0x25 string.


In other cases (not yet reduced to a small repro) we see:
  addr2line: Dwarf Error: Could not find abbrev number 127