as: Loc_mark_labels

 
 7.58 '.loc_mark_labels ENABLE'
 ==============================
 
 When emitting DWARF2 line number information, the '.loc_mark_labels'
 directive makes the assembler emit an entry to the '.debug_line' line
 number matrix with the 'basic_block' register in the state machine set
 whenever a code label is seen.  The ENABLE argument should be either 1
 or 0, to enable or disable this function respectively.