In the table of attribute form encodings table (Figure 21 page 161) in the specification for DWARF4 (here) there is a gap. The entries go
Form name Value Class DW_FORM_ref_udata 0x15 reference DW_FORM_indirect 0x16 (see Section 7.5.3) DW_FORM_sec_offset 0x17 lineptr, loclistptr, macptr, rangelistptr DW_FORM_exprloc 0x18 exprloc DW_FORM_flag_present 0x19 flag DW_FORM_ref_sig8 0x20 reference
Note the value counts from 0x19 to 0x20, not 0x1a as might be expected. A pleasing trap for unwary developers! I wondered if this the gap was left intentionally (perhaps to allow for future expansion) or by mistake but I can't find an answer one way or the other?
