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debug: Make sure to output .file 0 when generating DWARF5.

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When gas outputs DWARF5 .debug_line[_str] then we have to tell it the
comp_dir and main file name for the zero entry line table. Otherwise
gas has to guess at the CU compilation directory and file.

Before a gcc -gdwarf-5 ../src/hello.c line table looked like:

Directory table:
 0     ../src (24)
 1     ../src (24)
 2     /usr/include (31)

File name table:
 0     hello.c (16),  0
 1     hello.c (16),  1
 2     stdio.h (44),  2

With this patch it looks like:

Directory table:
 0     /tmp/obj (0)
 1     ../src (24)
 2     /usr/include (31)

File name table:
 0     ../src/hello.c (9),  0
 1     hello.c (16),  1
 2     stdio.h (44),  2

gcc/ChangeLog:

	* dwarf2out.c (dwarf2out_finish): Emit .file 0 entry when
	generating DWARF5 .debug_line table through gas.
This commit is contained in:
Mark Wielaard 2020-10-06 17:41:19 +02:00
parent baf4750fea
commit 3a9e6ee42a
1 changed files with 21 additions and 0 deletions
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21
gcc/dwarf2out.c
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@ -31768,6 +31768,27 @@ dwarf2out_finish (const char *filename)
ASM_OUTPUT_LABEL (asm_out_file, debug_line_section_label);
if (! output_asm_line_debug_info ())
output_line_info (false);
else if (asm_outputs_debug_line_str ())
{
/* When gas outputs DWARF5 .debug_line[_str] then we have to
tell it the comp_dir and main file name for the zero entry
line table. */
const char *comp_dir, *filename0;
comp_dir = comp_dir_string ();
if (comp_dir == NULL)
comp_dir = "";
filename0 = get_AT_string (comp_unit_die (), DW_AT_name);
if (filename0 == NULL)
filename0 = "";
fprintf (asm_out_file, "\t.file 0 ");
output_quoted_string (asm_out_file, remap_debug_filename (comp_dir));
fputc (' ', asm_out_file);
output_quoted_string (asm_out_file, remap_debug_filename (filename0));
fputc ('\n', asm_out_file);
}
if (dwarf_split_debug_info && info_section_emitted)
{