debug/97718 - fix abstract origin references after last change

The change to clear the external_die_map slot after creating
the concrete instance DIE broke abstract origin processing which
tried to make sure to have those point to the early abstract instance
and not the concrete instance.  The following restores this by
eventually following the abstract origin link in the concrete instance.

2020-11-05  Richard Biener  <rguenther@suse.de>

	PR debug/97718
	* dwarf2out.c (add_abstract_origin_attribute): Make sure to
	point to the abstract instance.

diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 64ac94a8cbd0f9456c27ba5ce70fa6c6f9d1bd7a..81cb7341a7e4e5b9b95424990ca07b6e4a6c7b8c 100644 (file)
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -21293,7 +21293,16 @@ add_abstract_origin_attribute (dw_die_ref die, tree origin)
      here.  */
 
   if (origin_die)
-    add_AT_die_ref (die, DW_AT_abstract_origin, origin_die);
+    {
+      dw_attr_node *a;
+      /* Like above, if we already created a concrete instance DIE
+        do not use that for the abstract origin but the early DIE
+        if present.  */
+      if (in_lto_p
+         && (a = get_AT (origin_die, DW_AT_abstract_origin)))
+       origin_die = AT_ref (a);
+      add_AT_die_ref (die, DW_AT_abstract_origin, origin_die);
+    }
 }
 
 /* We do not currently support the pure_virtual attribute.  */