GAS: Update the .section directive so that a numeric section index can be provided when the "o" flag is used.

	PR 26253
gas	* config/obj-elf.c (obj_elf_section): Accept a numeric value for
	the "o" section flag.  Interpret it as a section index.  Allow an
	index of zero.
	* doc/as.texi: Document the new behaviour.
	* NEWS: Mention the new feature.  Tidy entries.
	* testsuite/gas/elf/sh-link-zero.s: New test.
	* testsuite/gas/elf/sh-link-zero.d: New test driver.
	* testsuite/gas/elf/elf.exp: Run the new test.
	* testsuite/gas/elf/section21.l: Updated expected assembler
	output.

bfd	* elf.c (_bfd_elf_setup_sections): Do not complain about an
	sh_link value of zero when the SLF_LINK_ORDER flag is set.
	(assign_section_numbers): Likewise.

1 files changed, 10 insertions, 22 deletions

diff --git a/bfd/elf.c b/bfd/elf.c
index 0059402..9d7cbd5 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -848,16 +848,14 @@ _bfd_elf_setup_sections (bfd *abfd)
       if ((this_hdr->sh_flags & SHF_LINK_ORDER) != 0)
 	{
 	  unsigned int elfsec = this_hdr->sh_link;
-	  /* FIXME: The old Intel compiler and old strip/objcopy may
-	     not set the sh_link or sh_info fields.  Hence we could
-	     get the situation where elfsec is 0.  */
+	  /* An sh_link value of 0 is now allowed.  It indicates that linked
+	     to section has already been discarded, but that the current
+	     section has been retained for some other reason.  This linking
+	     section is still a candidate for later garbage collection
+	     however.  */
 	  if (elfsec == 0)
 	    {
-	      const struct elf_backend_data *bed = get_elf_backend_data (abfd);
-	      bed->link_order_error_handler
-		/* xgettext:c-format */
-		(_("%pB: warning: sh_link not set for section `%pA'"),
-		 abfd, s);
+	      elf_linked_to_section (s) = NULL;
 	    }
 	  else
 	    {
@@ -3888,6 +3886,10 @@ assign_section_numbers (bfd *abfd, struct bfd_link_info *link_info)
       if ((d->this_hdr.sh_flags & SHF_LINK_ORDER) != 0)
 	{
 	  s = elf_linked_to_section (sec);
+	  /* We can now have a NULL linked section pointer.
+	     This happens when the sh_link field is 0, which is done
+	     when a linked to section is discarded but the linking
+	     section has been retained for some reason.  */
 	  if (s)
 	    {
 	      /* Check discarded linkonce section.  */
@@ -3923,20 +3925,6 @@ assign_section_numbers (bfd *abfd, struct bfd_link_info *link_info)
 	      s = s->output_section;
 	      d->this_hdr.sh_link = elf_section_data (s)->this_idx;
 	    }
-	  else
-	    {
-	      /* PR 290:
-		 The Intel C compiler generates SHT_IA_64_UNWIND with
-		 SHF_LINK_ORDER.  But it doesn't set the sh_link or
-		 sh_info fields.  Hence we could get the situation
-		 where s is NULL.  */
-	      const struct elf_backend_data *bed
-		= get_elf_backend_data (abfd);
-	      bed->link_order_error_handler
-		/* xgettext:c-format */
-		(_("%pB: warning: sh_link not set for section `%pA'"),
-		 abfd, sec);
-	    }
 	}
 
       switch (d->this_hdr.sh_type)