bfd/

	* libbfd-in.h (_bfd_clear_contents): New prototype.
	* reloc.c (_bfd_clear_contents): New.
	* libbfd.h: Regenerated.

	* elf32-arm.c (elf32_arm_final_link_relocate): Use
	_bfd_clear_contents.
	* elf32-d10v.c (elf32_d10v_relocate_section): Likewise.
	* elf32-hppa.c (elf32_hppa_relocate_section): Likewise.
	* elf32-i386.c (elf_i386_relocate_section): Likewise.
	* elf32-ppc.c (ppc_elf_relocate_section): Likewise.
	* elf32-s390.c (elf_s390_relocate_section): Likewise.
	* elf32-sh.c (sh_elf_relocate_section): Likewise.
	* elf32-xtensa.c (elf_xtensa_relocate_section): Likewise.
	* elf64-ppc.c (ppc64_elf_relocate_section): Likewise.
	* elf64-s390.c (elf_s390_relocate_section): Likewise.
	* elf64-x86-64.c (elf64_x86_64_relocate_section): Likewise.
	* elfxx-sparc.c (_bfd_sparc_elf_relocate_section): Likewise.

	* elfxx-ia64.c (elfNN_ia64_relocate_section): Set value to
	zero for discarded symbols.
	* elfxx-mips.c (mips_elf_calculate_relocation): Likewise.
ld/testsuite/
	* ld-discard/zero-rel.d, ld-discard/zero-rel.s: New files.

1 files changed, 66 insertions, 0 deletions

diff --git a/bfd/reloc.c b/bfd/reloc.c
index 09b888f3d5..1b8c8d75e7 100644
--- a/bfd/reloc.c
+++ b/bfd/reloc.c
@@ -1544,6 +1544,72 @@ _bfd_relocate_contents (reloc_howto_type *howto,
   return flag;
 }
 
+/* Clear a given location using a given howto, by applying a relocation value
+   of zero and discarding any in-place addend.  This is used for fixed-up
+   relocations against discarded symbols, to make ignorable debug or unwind
+   information more obvious.  */
+
+void
+_bfd_clear_contents (reloc_howto_type *howto,
+		     bfd *input_bfd,
+		     bfd_byte *location)
+{
+  int size;
+  bfd_vma x = 0;
+
+  /* Get the value we are going to relocate.  */
+  size = bfd_get_reloc_size (howto);
+  switch (size)
+    {
+    default:
+    case 0:
+      abort ();
+    case 1:
+      x = bfd_get_8 (input_bfd, location);
+      break;
+    case 2:
+      x = bfd_get_16 (input_bfd, location);
+      break;
+    case 4:
+      x = bfd_get_32 (input_bfd, location);
+      break;
+    case 8:
+#ifdef BFD64
+      x = bfd_get_64 (input_bfd, location);
+#else
+      abort ();
+#endif
+      break;
+    }
+
+  /* Zero out the unwanted bits of X.  */
+  x &= ~howto->dst_mask;
+
+  /* Put the relocated value back in the object file.  */
+  switch (size)
+    {
+    default:
+    case 0:
+      abort ();
+    case 1:
+      bfd_put_8 (input_bfd, x, location);
+      break;
+    case 2:
+      bfd_put_16 (input_bfd, x, location);
+      break;
+    case 4:
+      bfd_put_32 (input_bfd, x, location);
+      break;
+    case 8:
+#ifdef BFD64
+      bfd_put_64 (input_bfd, x, location);
+#else
+      abort ();
+#endif
+      break;
+    }
+}
+
 /*
 DOCDD
 INODE