Mark the plugin symbol undefined

LTO may optimize out a plugin symbol, which is also referenced by a
non-IR file.  When that happens, we should mark the plugin symbol
undefined.  It isn't the problem since LTO already determined the
symbols in the non-IR file aren't used.

bfd/

	PR ld/12365
	PR ld/14272
	* elflink.c (_bfd_elf_fix_symbol_flags): Mark the plugin symbol
	undefined if it is referenced from a non-IR file.

ld/testsuite/

	PR ld/12365
	* ld-plugin/pr12365a.c: New file.
	* ld-plugin/pr12365b.c: Likewise.
	* ld-plugin/pr12365c.c: Likewise.

	* ld-plugin/lto.exp (lto_link_tests): Prepare for the PR ld/12365
	test.
	Run the PR ld/12365 test.

1 files changed, 14 insertions, 0 deletions

diff --git a/bfd/elflink.c b/bfd/elflink.c
index 26af870..604cfb6 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -2423,6 +2423,20 @@ _bfd_elf_fix_symbol_flags (struct elf_link_hash_entry *h,
     }
   else
     {
+      /* If a plugin symbol is referenced from a non-IR file, mark
+         the symbol as undefined, except for symbol for linker
+	 created section.  */
+      if (h->root.non_ir_ref
+	  && (h->root.type == bfd_link_hash_defined
+	      || h->root.type == bfd_link_hash_defweak)
+	  && (h->root.u.def.section->flags & SEC_LINKER_CREATED) == 0
+	  && h->root.u.def.section->owner != NULL
+	  && (h->root.u.def.section->owner->flags & BFD_PLUGIN) != 0)
+	{
+	  h->root.type = bfd_link_hash_undefined;
+	  h->root.u.undef.abfd = h->root.u.def.section->owner;
+	}
+
       /* Unfortunately, NON_ELF is only correct if the symbol
 	 was first seen in a non-ELF file.  Fortunately, if the symbol
 	 was first seen in an ELF file, we're probably OK unless the