Evaluate __start_* and __stop_* symbol PROVIDE expressions early

Makes these symbols defined before bfd_elf_size_dynamic_sections, to
avoid horrible hacks elsewhere.  The exp_fold_tree undefweak change
is necessary to define undefweak symbols early too.  The comment was
wrong.  PROVIDE in fact defines undefweak symbols, via
bfd_elf_record_link_assignment.

	PR ld/19175
	* ldlang.c (lang_insert_orphan): Evaluate __start_* and __stop_*
	symbol PROVIDE expressions.
	* ldexp.c (exp_fold_tree_1 <etree_provide>): Define undefweak
	references.

1 files changed, 5 insertions, 2 deletions

diff --git a/ld/ldexp.c b/ld/ldexp.c
index 7694f7b..2ec8eb6 100644
--- a/ld/ldexp.c
+++ b/ld/ldexp.c
@@ -1126,11 +1126,14 @@ exp_fold_tree_1 (etree_type *tree)
 	      if (h == NULL
 		  || !(h->type == bfd_link_hash_new
 		       || h->type == bfd_link_hash_undefined
+		       || h->type == bfd_link_hash_undefweak
 		       || h->linker_def))
 		{
 		  /* Do nothing.  The symbol was never referenced, or
-		     was defined in some object file.  Undefined weak
-		     symbols stay undefined.  */
+		     was defined in some object file.  Note that
+		     undefweak symbols are defined by PROVIDE.  This
+		     is to support glibc use of __rela_iplt_start and
+		     similar weak references.  */
 		  break;
 		}
 	    }