Revert PR16467 change

This reverts the pr16467 change, which was incorrect due to faulty
analysis of the pr16467 testcase.  The failure was not due to a
mismatch in symbol type (ifunc/non-ifunc) but due to a symbol loop
being set up.

See https://sourceware.org/ml/binutils/2016-06/msg00013.html for some
rambling on versioned symbols and ELF shared library symbol overriding
that explain this patch.

bfd/
	PR ld/20159
	PR ld/16467
	* elflink.c (_bfd_elf_merge_symbol): Revert PR16467 change.
	(_bfd_elf_add_default_symbol): Don't indirect to/from defined
	symbol given a version by a script different to the version
	of the symbol being added.
	(elf_link_add_object_symbols): Use _bfd_elf_strtab_save and
	_bfd_elf_strtab_restore.  Don't fudge dynstr references.
	* elf-strtab.c (_bfd_elf_strtab_restore_size): Delete.
	(struct strtab_save): New.
	(_bfd_elf_strtab_save, _bfd_elf_strtab_restore): New functions.
	* elf-bfd.h (_bfd_elf_strtab_restore_size): Delete.
	(_bfd_elf_strtab_save, _bfd_elf_strtab_restore): Declare.

1 files changed, 35 insertions, 6 deletions

diff --git a/bfd/elf-strtab.c b/bfd/elf-strtab.c
index ca8ac33..19b0ad8 100644
--- a/bfd/elf-strtab.c
+++ b/bfd/elf-strtab.c
@@ -215,16 +215,45 @@ _bfd_elf_strtab_clear_all_refs (struct elf_strtab_hash *tab)
     tab->array[idx]->refcount = 0;
 }
 
-/* Downsizes strtab.  Entries from IDX up to the current size are
-   removed from the array.  */
+/* Save strtab refcounts prior to adding --as-needed library.  */
+
+struct strtab_save
+{
+  bfd_size_type size;
+  unsigned int refcount[1];
+};
+
+void *
+_bfd_elf_strtab_save (struct elf_strtab_hash *tab)
+{
+  struct strtab_save *save;
+  bfd_size_type idx, size;
+
+  size = sizeof (*save) + (tab->size - 1) * sizeof (save->refcount[0]);
+  save = bfd_malloc (size);
+  if (save == NULL)
+    return save;
+
+  save->size = tab->size;
+  for (idx = 1; idx < tab->size; idx++)
+    save->refcount[idx] = tab->array[idx]->refcount;
+  return save;
+}
+
+/* Restore strtab refcounts on finding --as-needed library not needed.  */
+
 void
-_bfd_elf_strtab_restore_size (struct elf_strtab_hash *tab, bfd_size_type idx)
+_bfd_elf_strtab_restore (struct elf_strtab_hash *tab, void *buf)
 {
-  bfd_size_type curr_size = tab->size;
+  bfd_size_type idx, curr_size = tab->size;
+  struct strtab_save *save = (struct strtab_save *) buf;
 
   BFD_ASSERT (tab->sec_size == 0);
-  BFD_ASSERT (idx <= curr_size);
-  tab->size = idx;
+  BFD_ASSERT (save->size <= curr_size);
+  tab->size = save->size;
+  for (idx = 1; idx < save->size; ++idx)
+    tab->array[idx]->refcount = save->refcount[idx];
+
   for (; idx < curr_size; ++idx)
     {
       /* We don't remove entries from the hash table, just set their