Index PowerPC64 linker generated .eh_frame in .eh_frame_hdr

I noticed recently that .eh_frame FDEs generated by the linker for
call stubs and .glink weren't being indexed in .eh_frame_hdr, due to
bfd_elf_discard_info being run before the linker generated .eh_frame
sections were available for parsing.  This patch moves code around in
elf64-ppc.c and ppc64elf.em to avoid that problem.

Another problem fixed here is that --gc-sections parses .eh_frame
early, and the existing machinery allows only one go at parsing the
.eh_frame sections.  That resulted in the linker generated .eh_frame
CIEs not being merged and no .eh_frame_hdr index entries for those
FDEs.  It turns out that all the info from parsing .eh_frame is
attached to the section, so order of parsing isn't important, and
after parsing sec_info_type being set will prevent a section being
parsed again.  At least, when parsing doesn't hit an error.  So there
isn't really any need for "parsed_eh_frame".  "merge_cies" is also
redundant, which means _bfd_elf_{begin,end}_eh_frame_parsing can also
disappear.

bfd/
	* elf-bfd.h (struct eh_frame_hdr_info): Delete merge_cies and
	parsed_eh_frames.
	(_bfd_elf_begin_eh_frame_parsing): Delete.
	(_bfd_elf_end_eh_frame_parsing): Delete.
	* elf-eh-frame.c (_bfd_elf_begin_eh_frame_parsing): Delete.
	(_bfd_elf_end_eh_frame_parsing): Delete.
	(_bfd_elf_parse_eh_frame): Don't test parsed_eh_frame.  Test
	!info->relocatable in place of merge_cies.
	* elflink.c (bfd_elf_gc_sections, bfd_elf_discard_info): Adjust.
	* elf64-ppc.c (glink_eh_frame_cie): Pad to multiple of 8.
	(ppc64_elf_size_stubs): Likewise pad stub FDE.
	(ppc64_elf_build_stubs): Move code setting glink .eh_frame to..
	(ppc64_elf_size_stubs): ..here and..
	(ppc64_elf_finish_dynamic_sections): ..here.
ld/
	* emultempl/ppc64elf.em (gld${EMULATION_NAME}_after_allocation): Call
	bfd_elf_discard_info after generating glink .eh_frame.  Delete
	redundant test on ppc64_elf_setup_section_lists status.

bfd/elflink.c

@@ -12154,6 +12154,7 @@ bfd_elf_gc_sections (bfd *abfd, struct bfd_link_info *info)
   bfd *sub;
   elf_gc_mark_hook_fn gc_mark_hook;
   const struct elf_backend_data *bed = get_elf_backend_data (abfd);
+  struct elf_link_hash_table *htab;
 
   if (!bed->can_gc_sections
       || !is_elf_hash_table (info->hash))
@@ -12163,10 +12164,10 @@ bfd_elf_gc_sections (bfd *abfd, struct bfd_link_info *info)
     }
 
   bed->gc_keep (info);
+  htab = elf_hash_table (info);
 
   /* Try to parse each bfd's .eh_frame section.  Point elf_eh_frame_section
      at the .eh_frame section if we can mark the FDEs individually.  */
-  _bfd_elf_begin_eh_frame_parsing (info);
   for (sub = info->input_bfds; sub != NULL; sub = sub->link.next)
     {
       asection *sec;
@@ -12183,27 +12184,20 @@ bfd_elf_gc_sections (bfd *abfd, struct bfd_link_info *info)
 	  sec = bfd_get_next_section_by_name (sec);
 	}
     }
-  _bfd_elf_end_eh_frame_parsing (info);
 
   /* Apply transitive closure to the vtable entry usage info.  */
-  elf_link_hash_traverse (elf_hash_table (info),
-			  elf_gc_propagate_vtable_entries_used,
-			  &ok);
+  elf_link_hash_traverse (htab, elf_gc_propagate_vtable_entries_used, &ok);
   if (!ok)
     return FALSE;
 
   /* Kill the vtable relocations that were not used.  */
-  elf_link_hash_traverse (elf_hash_table (info),
-			  elf_gc_smash_unused_vtentry_relocs,
-			  &ok);
+  elf_link_hash_traverse (htab, elf_gc_smash_unused_vtentry_relocs, &ok);
   if (!ok)
     return FALSE;
 
   /* Mark dynamically referenced symbols.  */
-  if (elf_hash_table (info)->dynamic_sections_created)
-    elf_link_hash_traverse (elf_hash_table (info),
-			    bed->gc_mark_dynamic_ref,
-			    info);
+  if (htab->dynamic_sections_created)
+    elf_link_hash_traverse (htab, bed->gc_mark_dynamic_ref, info);
 
   /* Grovel through relocs to find out who stays ...  */
   gc_mark_hook = bed->gc_mark_hook;
@@ -12682,7 +12676,6 @@ bfd_elf_discard_info (bfd *output_bfd, struct bfd_link_info *info)
     {
       asection *i;
 
-      _bfd_elf_begin_eh_frame_parsing (info);
       for (i = o->map_head.s; i != NULL; i = i->map_head.s)
 	{
 	  if (i->size == 0)
@@ -12703,7 +12696,6 @@ bfd_elf_discard_info (bfd *output_bfd, struct bfd_link_info *info)
 
 	  fini_reloc_cookie_for_section (&cookie, i);
 	}
-      _bfd_elf_end_eh_frame_parsing (info);
     }
 
   for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link.next)