PATCH: Handle section group for ld -r

PATCH: Handle section group for ld -r

[H. J. Lu]

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This patch fixes section group for ld -r.


H.J.

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2004-04-29  H.J. Lu  <hongjiu.lu@intel.com>

	* elf.c (bfd_section_from_shdr): Maintain the section order in
	a section group.
	(special_sections): Add ".note.GNU-stack".
	(elf_fake_sections): Handle section group for relocatable
	link..

--- bfd/elf.c.group	2004-04-26 21:11:41.000000000 -0700
+++ bfd/elf.c	2004-04-29 13:44:31.000000000 -0700
@@ -1945,8 +1945,10 @@ bfd_section_from_shdr (bfd *abfd, unsign
 	    hdr->bfd_section->flags
 	      |= SEC_LINK_ONCE | SEC_LINK_DUPLICATES_DISCARD;
 
+	  /* We try to keep the same section order as it comes in.  */
+	  idx += n_elt;
 	  while (--n_elt != 0)
-	    if ((s = (++idx)->shdr->bfd_section) != NULL
+	    if ((s = (--idx)->shdr->bfd_section) != NULL
 		&& elf_next_in_group (s) != NULL)
 	      {
 		elf_next_in_group (hdr->bfd_section) = s;
@@ -2054,6 +2056,7 @@ static struct bfd_elf_special_section co
   { ".gnu.version",   12,  0, SHT_GNU_versym, 0 },
   { ".gnu.version_d", 14,  0, SHT_GNU_verdef, 0 },
   { ".gnu.version_r", 14,  0, SHT_GNU_verneed, 0 },
+  { ".note.GNU-stack",15,  0, SHT_PROGBITS, 0 },
   { ".note",           5, -1, SHT_NOTE,     0 },
   { ".rela",           5, -1, SHT_RELA,     0 },
   { ".rel",            4, -1, SHT_REL,      0 },
@@ -2386,7 +2389,31 @@ elf_fake_sections (bfd *abfd, asection *
      asect->flags.  */
   if (this_hdr->sh_type == SHT_NULL)
     {
-      if ((asect->flags & SEC_ALLOC) != 0
+      if ((asect->flags & SEC_GROUP) != 0)
+	{
+	  /* We also need to mark SHF_GROUP here for relocatable
+	     link.  */
+	  struct bfd_link_order *l;
+	  asection *elt;
+
+	  for (l = asect->link_order_head; l != NULL; l = l->next)
+	    if (l->type == bfd_indirect_link_order
+		&& (elt = elf_next_in_group (l->u.indirect.section)) != NULL)
+	      do
+		{
+		  /* The name is not important. Anything will do.  */
+		  elf_group_name (elt->output_section) = "G";
+		  elf_section_flags (elt->output_section) |= SHF_GROUP;
+
+		  elt = elf_next_in_group (elt);
+		  /* During a relocatable link, the lists are
+		     circular.  */
+		}
+	      while (elt != elf_next_in_group (l->u.indirect.section));
+
+	  this_hdr->sh_type = SHT_GROUP;
+	}
+      else if ((asect->flags & SEC_ALLOC) != 0
 	  && (((asect->flags & (SEC_LOAD | SEC_HAS_CONTENTS)) == 0)
 	      || (asect->flags & SEC_NEVER_LOAD) != 0))
 	this_hdr->sh_type = SHT_NOBITS;

Re: PATCH: Handle section group for ld -r

[Alan Modra]

On Thu, Apr 29, 2004 at 01:50:47PM -0700, H. J. Lu wrote:
> This patch fixes section group for ld -r.

I doubt it.  :)  ld -r and sections groups are difficult to handle
correctly.  The problem is what to do with sections that have the same
name as sections belonging to the group.  Normally, ld -r would merge
such sections, leading to other sections incorrectly becoming part of
the group.  We need to stop that happening, which could be done easily
enough by modifying unique_section_p.  I'll take a look at that.

Meanwhile, I guess your patch is OK.

> 	* elf.c (bfd_section_from_shdr): Maintain the section order in
> 	a section group.
> 	(special_sections): Add ".note.GNU-stack".
> 	(elf_fake_sections): Handle section group for relocatable
> 	link..

-- 
Alan Modra
IBM OzLabs - Linux Technology Centre