clean-up: move writing of build attributes section into a function

- add obj_build_attributes to struct elf_backend_data similarly sframe.
- new function _bfd_elf_write_section_build_attributes encapsulating the
  writing of the build attributes section into a function.

bfd/elf-attrs.c

@@ -801,3 +801,21 @@ _bfd_elf_merge_unknown_attribute_list (bfd *ibfd, bfd *obfd)
 
   return result;
 }
+
+bool _bfd_elf_write_section_build_attributes (bfd *abfd,
+					      struct bfd_link_info *info ATTRIBUTE_UNUSED)
+{
+  asection *sec = elf_obj_build_attributes (abfd);
+
+  if (sec == NULL)
+    return true;
+
+  bfd_byte *contents = (bfd_byte *) bfd_malloc (sec->size);
+  if (contents == NULL)
+    return false; /* Bail out and fail.  */
+
+  bfd_elf_set_obj_attr_contents (abfd, contents, sec->size);
+  bfd_set_section_contents (abfd, sec, contents, 0, sec->size);
+  free (contents);
+  return true;
+}

bfd/elf-bfd.h

@@ -2030,6 +2030,9 @@ struct output_elf_obj_tdata
      created.  */
   asection *sframe;
 
+  /* Holds the build attributes section if it exists.  */
+  asection *obj_build_attributes;
+
   /* Used to determine if the e_flags field has been initialized */
   bool flags_init;
 };
@@ -2214,6 +2217,8 @@ struct elf_obj_tdata
 #define elf_next_file_pos(bfd)	(elf_tdata(bfd) -> o->next_file_pos)
 #define elf_stack_flags(bfd)	(elf_tdata(bfd) -> o->stack_flags)
 #define elf_sframe(bfd)		(elf_tdata(bfd) -> o->sframe)
+#define elf_obj_build_attributes(bfd) \
+				(elf_tdata(bfd) -> o->obj_build_attributes)
 #define elf_shstrtab(bfd)	(elf_tdata(bfd) -> o->strtab_ptr)
 #define elf_onesymtab(bfd)	(elf_tdata(bfd) -> symtab_section)
 #define elf_symtab_shndx_list(bfd)	(elf_tdata(bfd) -> symtab_shndx_list)
@@ -3065,6 +3070,8 @@ extern obj_attribute *bfd_elf_add_obj_attr_int_string
   bfd_elf_add_obj_attr_int_string ((BFD), OBJ_ATTR_PROC, (TAG), \
 				   (INTVAL), (STRVAL))
 
+extern bool _bfd_elf_write_section_build_attributes
+  (bfd *, struct bfd_link_info *);
 extern char *_bfd_elf_attr_strdup (bfd *, const char *);
 extern void _bfd_elf_copy_obj_attributes (bfd *, bfd *);
 extern int _bfd_elf_obj_attrs_arg_type (bfd *, int, unsigned int);

bfd/elflink.c

@@ -12610,9 +12610,6 @@ bfd_elf_final_link (bfd *abfd, struct bfd_link_info *info)
   size_t relr_entsize;
   asection *reldyn = 0;
   bfd_size_type amt;
-  asection *attr_section = NULL;
-  bfd_vma attr_size = 0;
-  const char *std_attrs_section;
   struct elf_link_hash_table *htab = elf_hash_table (info);
   bool sections_removed;
 
@@ -12658,12 +12655,12 @@ bfd_elf_final_link (bfd *abfd, struct bfd_link_info *info)
      sections from the link, and set the contents of the output
      section.  */
   sections_removed = false;
-  std_attrs_section = get_elf_backend_data (abfd)->obj_attrs_section;
+  const char *obj_attrs_section = get_elf_backend_data (abfd)->obj_attrs_section;
   for (o = abfd->sections; o != NULL; o = o->next)
     {
       bool remove_section = false;
 
-      if ((std_attrs_section && strcmp (o->name, std_attrs_section) == 0)
+      if ((obj_attrs_section && strcmp (o->name, obj_attrs_section) == 0)
 	  || strcmp (o->name, ".gnu.attributes") == 0)
 	{
 	  for (p = o->map_head.link_order; p != NULL; p = p->next)
@@ -12678,12 +12675,16 @@ bfd_elf_final_link (bfd *abfd, struct bfd_link_info *info)
 	      input_section->flags &= ~SEC_HAS_CONTENTS;
 	    }
 
-	  attr_size = bfd_elf_obj_attr_size (abfd);
-	  bfd_set_section_size (o, attr_size);
 	  /* Skip this section later on.  */
 	  o->map_head.link_order = NULL;
-	  if (attr_size)
-	    attr_section = o;
+
+	  bfd_vma attr_size = bfd_elf_obj_attr_size (abfd);
+	  /* Once ELF headers have been written, the size of a section is
+	     frozen. We need to set the size of the attribute section before
+	     _bfd_elf_compute_section_file_positions.  */
+	  bfd_set_section_size (o, attr_size);
+	  if (attr_size > 0)
+	    elf_obj_build_attributes (abfd) = o;
 	  else
 	    remove_section = true;
 	}
@@ -13798,21 +13799,14 @@ bfd_elf_final_link (bfd *abfd, struct bfd_link_info *info)
   if (! _bfd_elf_write_section_sframe (abfd, info))
     goto error_return;
 
+  if (! _bfd_elf_write_section_build_attributes (abfd, info))
+    goto error_ret2;
+
   if (info->callbacks->emit_ctf)
       info->callbacks->emit_ctf ();
 
   elf_final_link_free (abfd, &flinfo);
 
-  if (attr_section)
-    {
-      bfd_byte *contents = (bfd_byte *) bfd_malloc (attr_size);
-      if (contents == NULL)
-	goto error_ret2;
-      bfd_elf_set_obj_attr_contents (abfd, contents, attr_size);
-      bfd_set_section_contents (abfd, attr_section, contents, 0, attr_size);
-      free (contents);
-    }
-
   if (info->unique_symbol)
     bfd_hash_table_free (&flinfo.local_hash_table);
   return true;