[Bug lto/65015] LTO produces randomly ordered debug information

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65015

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to conchur from comment #2)
> Created attachment 34724 [details]
> Mini Testcases
> 
> Current results (the -COMPILE things are just out of curiosity):
> 
> SIMPLE-COMPILE: OK
> SIMPLE-LINK: OK
> LTO-COMPILE: FAIL

that's expected to fail

> LTO-LINK: FAIL
> LTO-OBJDUMP: OK
> LTO-EXTERNAL-DEBUG: FAIL
> LTO-STRIP-LINK: FAIL
> LTO-STRIP-EXTERNAL-DEBUG: FAIL
> LTO-BUILDID-LINK: FAIL
> LTO-SAVETEMPS-LINK: OK
> LTO-SAVETEMPS-EXTERNAL-DEBUG: OK
> 
> The -save-temps was a suggestion by Jérémy Bobbio and shows that there is
> still a problem with the random file names when trying to use LTO to create
> reproducible builds. At least for the simple one file case

-save-temps makes some of the names non-random.  I still expect that the patch
I just committed plus

Index: gcc/dwarf2out.c
===================================================================
--- gcc/dwarf2out.c     (revision 220613)
+++ gcc/dwarf2out.c     (working copy)
@@ -24521,8 +24521,11 @@ dwarf2out_finish (const char *filename)
   gen_remaining_tmpl_value_param_die_attribute ();

   /* Add the name for the main input file now.  We delayed this from
-     dwarf2out_init to avoid complications with PCH.  */
-  add_name_attribute (comp_unit_die (), remap_debug_filename (filename));
+     dwarf2out_init to avoid complications with PCH.
+     Avoid doing this for LTO produced units as it adds random
+     tempfile names.  */
+  if (!in_lto_p)
+    add_name_attribute (comp_unit_die (), remap_debug_filename (filename));
   if (!IS_ABSOLUTE_PATH (filename) || targetm.force_at_comp_dir)
     add_comp_dir_attribute (comp_unit_die ());
   else if (get_AT (comp_unit_die (), DW_AT_comp_dir) == NULL)

will fix all cases.  Indeed:

> ./t.sh 
SIMPLE-COMPILE: OK
SIMPLE-LINK: OK
LTO-COMPILE: FAIL
LTO-LINK: OK
LTO-OBJDUMP: OK
LTO-EXTERNAL-DEBUG: OK
LTO-STRIP-LINK: OK
LTO-STRIP-EXTERNAL-DEBUG: OK
LTO-BUILDID-LINK: OK
LTO-SAVETEMPS-LINK: OK
LTO-SAVETEMPS-EXTERNAL-DEBUG: OK

as expected.