[PATCH] Always keep sections marked with SEC_KEEP

[Alan Modra]

On Thu, Oct 22, 2015 at 12:24:53PM -0700, H.J. Lu wrote:
> diff --git a/bfd/elflink.c b/bfd/elflink.c
> index 73fe469..06df821 100644
> --- a/bfd/elflink.c
> +++ b/bfd/elflink.c
> @@ -12449,7 +12449,8 @@ elf_gc_sweep (bfd *abfd, struct bfd_link_info *info)
>  	      o->gc_mark = first->gc_mark;
>  	    }
>  
> -	  if (o->gc_mark)
> +	  /* Always keep sections marked with SEC_KEEP.  */
> +	  if (o->gc_mark || (o->flags & SEC_KEEP))
>  	    continue;
>  
>  	  /* Skip sweeping sections already excluded.  */

This is wrong.  You're breaking the gc-sections model (and ignoring
the special combination of both SEC_EXCLUDE and SEC_KEEP).  Sections
with SEC_KEEP are supposed to have gc_mark set by the call to
_bfd_elf_gc_mark in bfd_elf_gc_sections.

Hmm, actually the underlying problem is your PR11133 patch.
_bfd_elf_gc_mark_rsec is too late to be setting SEC_KEEP.

	PR ld/11133
	PR ld/19161
	* elflink.c (elf_gc_sweep): Revert last patch.
	(_bfd_elf_gc_mark_hook): Don't set SEC_KEEP here.

diff --git a/bfd/elflink.c b/bfd/elflink.c
index 2ed07e0..0bec93d 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -12109,7 +12109,7 @@ _bfd_elf_gc_mark_hook (asection *sec,
 		{
 		  sec = bfd_get_section_by_name (i, sec_name);
 		  if (sec)
-		    sec->flags |= SEC_KEEP;
+		    return sec;
 		}
 	    }
 	  break;
@@ -12457,8 +12457,7 @@ elf_gc_sweep (bfd *abfd, struct bfd_link_info *info)
 	      o->gc_mark = first->gc_mark;
 	    }
 
-	  /* Always keep sections marked with SEC_KEEP.  */
-	  if (o->gc_mark || (o->flags & SEC_KEEP))
+	  if (o->gc_mark)
 	    continue;
 
 	  /* Skip sweeping sections already excluded.  */
-- 
Alan Modra
Australia Development Lab, IBM