7.28 .file fileno filename

When emitting dwarf2 line number information .file assigns filenames to the .debug_line file name table. 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.

7.29 .loc fileno lineno [column] [options]

The .loc directive will add row to the .debug_line line number matrix corresponding to the immediately following assembly instruction. The fileno, lineno, and optional column arguments will be applied to the .debug_line state machine before the row is added.

The options are a sequence of the following tokens in any order:

basic_block

This option will set the basic_block register in the .debug_line state machine to true.

prologue_end

This option will set the prologue_end register in the .debug_line state machine to true.

epilogue_begin

This option will set the epilogue_begin register in the .debug_line state machine to true.

is_stmt value

This option will set the is_stmt register in the .debug_line state machine to value, which must be either 0 or 1.

isa value

This directive will set the isa register in the .debug_line state machine to value, which must be an unsigned integer.

7.30 .loc_mark_blocks enable

The .loc_mark_blocks 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.