5.11.3 File Directive

The .file fileno "filename" directive assigns filenames to the .debug_line file name table when emitting dwarf2 line-number information. The fileno operand should be a unique positive integer to use as the index of the entry in the table. The filename operand is a C string literal.

The detail of filename indices is exposed to the user because the filename table is shared with the .debug_info section of the dwarf2 debugging information, and thus the user must know the exact indices that table entries will have.