Removing empty PT_LOAD program headers

[Alan Modra]

The linker has been removing emtpy PT_LOAD headers for a while, but
not as yet in any officially released binutils.  I figure this might
be a little unexpected when a user has specified PHDRS in a linker
script, or for objcopy.  Fixed as follows.

	* elf.c (elf_modify_segment_map): Add remove_empty_load param.
	Don't remove empty PT_LOAD header if false.
	(_bfd_elf_map_sections_to_segments): If user phdrs, pass false
	to elf_modify_segment_map.
	(assign_file_positions_for_load_sections): Pass false to
	elf_modify_segment_map.

Index: bfd/elf.c
===================================================================
RCS file: /cvs/src/src/bfd/elf.c,v
retrieving revision 1.407
diff -u -p -r1.407 elf.c
--- bfd/elf.c	9 Aug 2007 23:13:41 -0000	1.407
+++ bfd/elf.c	12 Aug 2007 23:19:10 -0000
@@ -3446,7 +3446,9 @@ _bfd_elf_make_dynamic_segment (bfd *abfd
 /* Possibly add or remove segments from the segment map.  */
 
 static bfd_boolean
-elf_modify_segment_map (bfd *abfd, struct bfd_link_info *info)
+elf_modify_segment_map (bfd *abfd,
+			struct bfd_link_info *info,
+			bfd_boolean remove_empty_load)
 {
   struct elf_segment_map **m;
   const struct elf_backend_data *bed;
@@ -3473,7 +3475,7 @@ elf_modify_segment_map (bfd *abfd, struc
 	}
       (*m)->count = new_count;
 
-      if ((*m)->p_type == PT_LOAD && (*m)->count == 0)
+      if (remove_empty_load && (*m)->p_type == PT_LOAD && (*m)->count == 0)
 	*m = (*m)->next;
       else
 	m = &(*m)->next;
@@ -3498,9 +3500,10 @@ _bfd_elf_map_sections_to_segments (bfd *
   struct elf_segment_map *m;
   asection **sections = NULL;
   const struct elf_backend_data *bed = get_elf_backend_data (abfd);
+  bfd_boolean no_user_phdrs;
 
-  if (elf_tdata (abfd)->segment_map == NULL
-      && bfd_count_sections (abfd) != 0)
+  no_user_phdrs = elf_tdata (abfd)->segment_map == NULL;
+  if (no_user_phdrs && bfd_count_sections (abfd) != 0)
     {
       asection *s;
       unsigned int i;
@@ -3869,7 +3872,7 @@ _bfd_elf_map_sections_to_segments (bfd *
       elf_tdata (abfd)->segment_map = mfirst;
     }
 
-  if (!elf_modify_segment_map (abfd, info))
+  if (!elf_modify_segment_map (abfd, info, no_user_phdrs))
     return FALSE;
 
   for (count = 0, m = elf_tdata (abfd)->segment_map; m != NULL; m = m->next)
@@ -4015,7 +4018,7 @@ assign_file_positions_for_load_sections 
   unsigned int i, j;
 
   if (link_info == NULL
-      && !elf_modify_segment_map (abfd, link_info))
+      && !elf_modify_segment_map (abfd, link_info, FALSE))
     return FALSE;
 
   alloc = 0;

-- 
Alan Modra
Australia Development Lab, IBM