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.

18 files changed, 193 insertions, 24 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 052a2d1..3b97d52 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,27 @@
+2006-11-02  Daniel Jacobowitz  <dan@codesourcery.com>
+
+	* 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.
+
 2006-11-01  Thiemo Seufer  <ths@mips.com>
             David Ung  <davidu@mips.com>
 
diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index 2faac89..f8eff70 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -3664,7 +3664,10 @@ elf32_arm_final_link_relocate (reloc_howto_type *           howto,
 	 from removed linkonce sections, or sections discarded by
 	 a linker script.  */
       if (r_symndx == 0)
-	return bfd_reloc_ok;
+	{
+	  _bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
+	  return bfd_reloc_ok;
+	}
 
       /* Handle relocations which should use the PLT entry.  ABS32/REL32
 	 will use the symbol's value, which may point to a PLT entry, but we
diff --git a/bfd/elf32-d10v.c b/bfd/elf32-d10v.c
index e5d546a..8d7cd94 100644
--- a/bfd/elf32-d10v.c
+++ b/bfd/elf32-d10v.c
@@ -469,6 +469,16 @@ elf32_d10v_relocate_section (bfd *output_bfd,
 				   unresolved_reloc, warned);
 	}
 
+      if (r_symndx == 0)
+	{
+	  /* r_symndx will be zero only for relocs against symbols from
+	     removed linkonce sections, or sections discarded by a linker
+	     script.  For these relocs, we just want the section contents
+	     zeroed.  Avoid any special processing.  */
+	  _bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
+	  continue;
+	}
+
       if (h != NULL)
 	name = h->root.root.string;
       else
diff --git a/bfd/elf32-hppa.c b/bfd/elf32-hppa.c
index db6e842..c448aac 100644
--- a/bfd/elf32-hppa.c
+++ b/bfd/elf32-hppa.c
@@ -3942,8 +3942,14 @@ elf32_hppa_relocate_section (bfd *output_bfd,
 	  /* r_symndx will be zero only for relocs against symbols
 	     from removed linkonce sections, or sections discarded by
 	     a linker script.  */
-	  if (r_symndx == 0
-	      || (input_section->flags & SEC_ALLOC) == 0)
+	  if (r_symndx == 0)
+	    {
+	      _bfd_clear_contents (elf_hppa_howto_table + r_type, input_bfd,
+				   contents + rela->r_offset);
+	      break;
+	    }
+
+	  if ((input_section->flags & SEC_ALLOC) == 0)
 	    break;
 
 	  /* The reloc types handled here and this conditional
diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index 97054a5..7a83c73 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -2395,17 +2395,12 @@ elf_i386_relocate_section (bfd *output_bfd,
 
       if (r_symndx == 0)
 	{
-	/* r_symndx will be zero only for relocs against symbols from
-	   removed linkonce sections, or sections discarded by a linker
-	   script.  For these relocs, we just want the section contents
-	   zeroed.  Avoid any special processing in the switch below.  */
-	  r_type = R_386_NONE;
-
-	  relocation = 0;
-	  if (howto->pc_relative)
-	    relocation = (input_section->output_section->vma
-			  + input_section->output_offset
-			  + rel->r_offset);
+	  /* r_symndx will be zero only for relocs against symbols from
+	     removed linkonce sections, or sections discarded by a linker
+	     script.  For these relocs, we just want the section contents
+	     zeroed.  Avoid any special processing.  */
+	  _bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
+	  continue;
 	}
 
       switch (r_type)
diff --git a/bfd/elf32-ppc.c b/bfd/elf32-ppc.c
index 59bac50..281fab0 100644
--- a/bfd/elf32-ppc.c
+++ b/bfd/elf32-ppc.c
@@ -6180,7 +6180,10 @@ ppc_elf_relocate_section (bfd *output_bfd,
 	     a linker script.  */
 	dodyn:
 	  if (r_symndx == 0)
-	    break;
+	    {
+	      _bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
+	      break;
+	    }
 	  /* Fall thru.  */
 
 	  if ((input_section->flags & SEC_ALLOC) == 0)
diff --git a/bfd/elf32-s390.c b/bfd/elf32-s390.c
index 83bf5e1..01ee6a5 100644
--- a/bfd/elf32-s390.c
+++ b/bfd/elf32-s390.c
@@ -2543,8 +2543,13 @@ elf_s390_relocate_section (output_bfd, info, input_bfd, input_section,
 	  /* r_symndx will be zero only for relocs against symbols
 	     from removed linkonce sections, or sections discarded by
 	     a linker script.  */
-	  if (r_symndx == 0
-	      || (input_section->flags & SEC_ALLOC) == 0)
+	  if (r_symndx == 0)
+	    {
+	      _bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
+	      break;
+	    }
+
+	  if ((input_section->flags & SEC_ALLOC) == 0)
 	    break;
 
 	  if ((info->shared
diff --git a/bfd/elf32-sh.c b/bfd/elf32-sh.c
index 85f3d8f..8e53056 100644
--- a/bfd/elf32-sh.c
+++ b/bfd/elf32-sh.c
@@ -3557,6 +3557,15 @@ sh_elf_relocate_section (bfd *output_bfd, struct bfd_link_info *info,
 	case R_SH_IMM_MEDHI16_PCREL:
 	case R_SH_IMM_HI16_PCREL:
 #endif
+	  /* r_symndx will be zero only for relocs against symbols
+	     from removed linkonce sections, or sections discarded by
+	     a linker script.  */
+	  if (r_symndx == 0)
+	    {
+	      _bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
+	      continue;
+	    }
+
 	  if (info->shared
 	      && (h == NULL
 		  || ELF_ST_VISIBILITY (h->other) == STV_DEFAULT
diff --git a/bfd/elf32-xtensa.c b/bfd/elf32-xtensa.c
index 34f7f47..59ed4ba 100644
--- a/bfd/elf32-xtensa.c
+++ b/bfd/elf32-xtensa.c
@@ -2270,6 +2270,16 @@ elf_xtensa_relocate_section (bfd *output_bfd,
 	  return FALSE;
 	}
 
+      if (r_symndx == 0)
+	{
+	  /* r_symndx will be zero only for relocs against symbols from
+	     removed linkonce sections, or sections discarded by a linker
+	     script.  For these relocs, we just want the section contents
+	     zeroed.  Avoid any special processing.  */
+	  _bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
+	  continue;
+	}
+
       /* There's no point in calling bfd_perform_relocation here.
 	 Just go directly to our "special function".  */
       r = elf_xtensa_do_reloc (howto, input_bfd, input_section,
diff --git a/bfd/elf64-ppc.c b/bfd/elf64-ppc.c
index 886f987..52b3e62 100644
--- a/bfd/elf64-ppc.c
+++ b/bfd/elf64-ppc.c
@@ -10728,7 +10728,11 @@ ppc64_elf_relocate_section (bfd *output_bfd,
 	     a linker script.  */
 	dodyn:
 	  if (r_symndx == 0)
-	    break;
+	    {
+	      _bfd_clear_contents (ppc64_elf_howto_table[r_type], input_bfd,
+				   contents + rel->r_offset);
+	      break;
+	    }
 	  /* Fall thru.  */
 
 	dodyn2:
diff --git a/bfd/elf64-s390.c b/bfd/elf64-s390.c
index 1d86820..443f325 100644
--- a/bfd/elf64-s390.c
+++ b/bfd/elf64-s390.c
@@ -2522,8 +2522,13 @@ elf_s390_relocate_section (output_bfd, info, input_bfd, input_section,
 	  /* r_symndx will be zero only for relocs against symbols
 	     from removed linkonce sections, or sections discarded by
 	     a linker script.  */
-	  if (r_symndx == 0
-	      || (input_section->flags & SEC_ALLOC) == 0)
+	  if (r_symndx == 0)
+	    {
+	      _bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
+	      break;
+	    }
+
+	  if ((input_section->flags & SEC_ALLOC) == 0)
 	    break;
 
 	  if ((info->shared
diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index 2556fdc..b6c973f 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -2370,8 +2370,13 @@ elf64_x86_64_relocate_section (bfd *output_bfd, struct bfd_link_info *info,
 	  /* r_symndx will be zero only for relocs against symbols
 	     from removed linkonce sections, or sections discarded by
 	     a linker script.  */
-	  if (r_symndx == 0
-	      || (input_section->flags & SEC_ALLOC) == 0)
+	  if (r_symndx == 0)
+	    {
+	      _bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
+	      break;
+	    }
+
+	  if ((input_section->flags & SEC_ALLOC) == 0)
 	    break;
 
 	  if ((info->shared
diff --git a/bfd/elfxx-ia64.c b/bfd/elfxx-ia64.c
index dbea35b..2fc5550 100644
--- a/bfd/elfxx-ia64.c
+++ b/bfd/elfxx-ia64.c
@@ -4751,6 +4751,12 @@ elfNN_ia64_relocate_section (output_bfd, info, input_bfd, input_section,
 	case R_IA64_LTV32LSB:
 	case R_IA64_LTV64MSB:
 	case R_IA64_LTV64LSB:
+	  /* r_symndx will be zero only for relocs against symbols
+	     from removed linkonce sections, or sections discarded by
+	     a linker script.  */
+	  if (r_symndx == 0)
+	    value = 0;
+
 	  r = elfNN_ia64_install_value (hit_addr, value, r_type);
 	  break;
 
diff --git a/bfd/elfxx-mips.c b/bfd/elfxx-mips.c
index 747c91c..8f1fb6d 100644
--- a/bfd/elfxx-mips.c
+++ b/bfd/elfxx-mips.c
@@ -4323,6 +4323,11 @@ mips_elf_calculate_relocation (bfd *abfd, bfd *input_bfd,
 						   input_section))
 	    return bfd_reloc_undefined;
 	}
+      else if (r_symndx == 0)
+	/* r_symndx will be zero only for relocs against symbols
+	   from removed linkonce sections, or sections discarded by
+	   a linker script.  */
+	value = 0;
       else
 	{
 	  if (r_type != R_MIPS_REL32)
diff --git a/bfd/elfxx-sparc.c b/bfd/elfxx-sparc.c
index 77ffbfe..3b64aca 100644
--- a/bfd/elfxx-sparc.c
+++ b/bfd/elfxx-sparc.c
@@ -2755,8 +2755,13 @@ _bfd_sparc_elf_relocate_section (bfd *output_bfd, struct bfd_link_info *info,
 	  /* r_symndx will be zero only for relocs against symbols
 	     from removed linkonce sections, or sections discarded by
 	     a linker script.  */
-	  if (r_symndx == 0
-	      || (input_section->flags & SEC_ALLOC) == 0)
+	  if (r_symndx == 0)
+	    {
+	      _bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
+	      break;
+	    }
+
+	  if ((input_section->flags & SEC_ALLOC) == 0)
 	    break;
 
 	  if ((info->shared
diff --git a/bfd/libbfd-in.h b/bfd/libbfd-in.h
index a9c96db..3de9ed4 100644
--- a/bfd/libbfd-in.h
+++ b/bfd/libbfd-in.h
@@ -547,6 +547,10 @@ extern bfd_reloc_status_type _bfd_final_link_relocate
 extern bfd_reloc_status_type _bfd_relocate_contents
   (reloc_howto_type *, bfd *, bfd_vma, bfd_byte *);
 
+/* Clear a given location using a given howto.  */
+extern void _bfd_clear_contents (reloc_howto_type *howto, bfd *input_bfd,
+				 bfd_byte *location);
+
 /* Link stabs in sections in the first pass.  */
 
 extern bfd_boolean _bfd_link_section_stabs
diff --git a/bfd/libbfd.h b/bfd/libbfd.h
index 92dfc15..8c55264 100644
--- a/bfd/libbfd.h
+++ b/bfd/libbfd.h
@@ -552,6 +552,10 @@ extern bfd_reloc_status_type _bfd_final_link_relocate
 extern bfd_reloc_status_type _bfd_relocate_contents
   (reloc_howto_type *, bfd *, bfd_vma, bfd_byte *);
 
+/* Clear a given location using a given howto.  */
+extern void _bfd_clear_contents (reloc_howto_type *howto, bfd *input_bfd,
+				 bfd_byte *location);
+
 /* Link stabs in sections in the first pass.  */
 
 extern bfd_boolean _bfd_link_section_stabs
diff --git a/bfd/reloc.c b/bfd/reloc.c
index 09b888f..1b8c8d7 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