as: File

1 
1 7.33 '.file'
1 ============
1 
1 There are two different versions of the '.file' directive.  Targets that
1 support DWARF2 line number information use the DWARF2 version of
1 '.file'.  Other targets use the default version.
1 
1 Default Version
1 ---------------
1 
1 This version of the '.file' directive tells 'as' that we are about to
1 start a new logical file.  The syntax is:
1 
1      .file STRING
1 
1    STRING is the new file name.  In general, the filename is recognized
1 whether or not it is surrounded by quotes '"'; but if you wish to
1 specify an empty file name, you must give the quotes-'""'.  This
1 statement may go away in future: it is only recognized to be compatible
1 with old 'as' programs.
1 
1 DWARF2 Version
1 --------------
1 
1 When emitting DWARF2 line number information, '.file' assigns filenames
1 to the '.debug_line' file name table.  The syntax is:
1 
1      .file FILENO FILENAME
1 
1    The FILENO operand should be a unique positive integer to use as the
1 index of the entry in the table.  The FILENAME operand is a C string
1 literal.
1 
1    The detail of filename indices is exposed to the user because the
1 filename table is shared with the '.debug_info' section of the DWARF2
1 debugging information, and thus the user must know the exact indices
1 that table entries will have.
1