PR ld/20276: Set non_ir_ref on common symbol

Also, don't check alignment on symbol from plugin dummy input.

bfd/
	PR ld/20276
	* elflink.c (elf_link_add_object_symbols): Don't check alignment
	on symbol from plugin dummy input.
ld/
	PR ld/20276
	* plugin.c (plugin_notice): Set non_ir_ref on common symbols.
	* testsuite/ld-plugin/lto.exp (lto_link_tests): Add test for
	PR ld/20276.
	(lto_run_tests): Likewise.
	* testsuite/ld-plugin/pass.out: New file.
	* testsuite/ld-plugin/pr20276a.c: Likewise.
	* testsuite/ld-plugin/pr20276b.c: Likewise.

1 files changed, 23 insertions, 13 deletions

diff --git a/ld/plugin.c b/ld/plugin.c
index cb6131841d6..4c161d1796c 100644
--- a/ld/plugin.c
+++ b/ld/plugin.c
@@ -1325,20 +1325,30 @@ plugin_notice (struct bfd_link_info *info,
 	  h->non_ir_ref = TRUE;
 	}
 
-      /* Otherwise, it must be a new def.  Ensure any symbol defined
-	 in an IR dummy BFD takes on a new value from a real BFD.
-	 Weak symbols are not normally overridden by a new weak
-	 definition, and strong symbols will normally cause multiple
-	 definition errors.  Avoid this by making the symbol appear
-	 to be undefined.  */
-      else if (((h->type == bfd_link_hash_defweak
-		 || h->type == bfd_link_hash_defined)
-		&& is_ir_dummy_bfd (sym_bfd = h->u.def.section->owner))
-	       || (h->type == bfd_link_hash_common
-		   && is_ir_dummy_bfd (sym_bfd = h->u.c.p->section->owner)))
+      /* Otherwise, it must be a new def.  */
+      else
 	{
-	  h->type = bfd_link_hash_undefweak;
-	  h->u.undef.abfd = sym_bfd;
+	  /* A common symbol should be merged with other commons or
+	     defs with the same name.  In particular, a common ought
+	     to be overridden by a def in a -flto object.  In that
+	     sense a common is also a ref.  */
+	  if (bfd_is_com_section (section))
+	    h->non_ir_ref = TRUE;
+
+	  /* Ensure any symbol defined in an IR dummy BFD takes on a
+	     new value from a real BFD.  Weak symbols are not normally
+	     overridden by a new weak definition, and strong symbols
+	     will normally cause multiple definition errors.  Avoid
+	     this by making the symbol appear to be undefined.  */
+	  if (((h->type == bfd_link_hash_defweak
+		|| h->type == bfd_link_hash_defined)
+	       && is_ir_dummy_bfd (sym_bfd = h->u.def.section->owner))
+	      || (h->type == bfd_link_hash_common
+		  && is_ir_dummy_bfd (sym_bfd = h->u.c.p->section->owner)))
+	    {
+	      h->type = bfd_link_hash_undefweak;
+	      h->u.undef.abfd = sym_bfd;
+	    }
 	}
     }