On Wed, Nov 6, 2024 at 3:35 PM Michal Jires <mji...@suse.cz> wrote:
>
> This if branch checks for comdat_type_p (GTY union tag) and then uses
> incorrect union variant die_id.die_symbol. There is no way to create
> this combination of valid values even if we ignore the GTY.
>
> Running testsuite with abort() in branch confirms that it is never taken.
Did you test with -fdebug-types-section? This code should be still needed
to generate the linkonce debug-type sections. Note it doesn't work (very well)
when combined with LTO.
Richard.
> gcc/ChangeLog:
>
> * dwarf2out.cc (output_comp_unit): Delete dead code.
> ---
> gcc/dwarf2out.cc | 25 +++++--------------------
> 1 file changed, 5 insertions(+), 20 deletions(-)
>
> diff --git a/gcc/dwarf2out.cc b/gcc/dwarf2out.cc
> index 38aedb64470..e10a5c78fe9 100644
> --- a/gcc/dwarf2out.cc
> +++ b/gcc/dwarf2out.cc
> @@ -11234,8 +11234,7 @@ static void
> output_comp_unit (dw_die_ref die, int output_if_empty,
> const unsigned char *dwo_id)
> {
> - const char *secname, *oldsym;
> - char *tmp;
> + const char *oldsym;
>
> /* Unless we are outputting main CU, we may throw away empty ones. */
> if (!output_if_empty && die->die_child == NULL)
> @@ -11269,21 +11268,10 @@ output_comp_unit (dw_die_ref die, int
> output_if_empty,
> calc_die_sizes (die);
>
> oldsym = die->die_id.die_symbol;
> - if (oldsym && die->comdat_type_p)
> - {
> - tmp = XALLOCAVEC (char, strlen (oldsym) + 24);
>
> - sprintf (tmp, ".gnu.linkonce.wi.%s", oldsym);
> - secname = tmp;
> - die->die_id.die_symbol = NULL;
> - switch_to_section (get_section (secname, SECTION_DEBUG, NULL));
> - }
> - else
> - {
> - switch_to_section (debug_info_section);
> - ASM_OUTPUT_LABEL (asm_out_file, debug_info_section_label);
> - info_section_emitted = true;
> - }
> + switch_to_section (debug_info_section);
> + ASM_OUTPUT_LABEL (asm_out_file, debug_info_section_label);
> + info_section_emitted = true;
>
> /* For LTO cross unit DIE refs we want a symbol on the start of the
> debuginfo section, not on the CU DIE. */
> @@ -11322,10 +11310,7 @@ output_comp_unit (dw_die_ref die, int
> output_if_empty,
> /* Leave the marks on the main CU, so we can check them in
> output_pubnames. */
> if (oldsym)
> - {
> - unmark_dies (die);
> - die->die_id.die_symbol = oldsym;
> - }
> + unmark_dies (die);
> }
>
> /* Whether to generate the DWARF accelerator tables in .debug_pubnames
> --
> 2.47.0
>
