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[AArch64] Remove duplicated code when handling some GOT relocations types


I found there are quite a few duplicated code supporting several GP based
relocation types.  They are:

  BFD_RELOC_AARCH64_LD64_GOTOFF_LO15
  BFD_RELOC_AARCH64_MOVW_GOTOFF_G0_NC
  BFD_RELOC_AARCH64_MOVW_GOTOFF_G1

These relocation types are supposed to be used for large memory model PIC/pic
mode under which we will have an initialized GP register points to the base of
GOT table, then these relocations are supposed to put the distance between GOT
entry and GOT table base address into the related instructions.

So, the parameters required to calculate the relocation should be the same as
BFD_RELOC_AARCH64_LD64_GOTPAGE_LO15 etc, all of them are require the GOT entry
address and GOT table base address to perform the relocation.

This patch has removed those duplicated code when handling above listed
relocation types,  grouped them with others as relocation types that are
require GOT table base address during performing relocation, reused the
existed GOT handling code.

The relocation calculation for these types before and after this patch should be
identical.

No regression on native check-ld and cross check-binutils/as/ld/gcc/g++ though I
think there is no use of these relocations types in gcc yet.

OK for master?

bfd/
2017-06-23  Jiong Wang  <jiong.wang@arm.com>

	* elfnn-aarch64.c (aarch64_relocation_aginst_gp_p): New function.
	(elfNN_aarch64_final_link_relocate): Delete duplicated code for
	BFD_RELOC_AARCH64_LD64_GOTOFF_LO15, BFD_RELOC_AARCH64_MOVW_GOTOFF_G0_NC,
	BFD_RELOC_AARCH64_MOVW_GOTOFF_G1.
	* elfxx-aarch64.c (_bfd_aarch64_elf_resolve_relocation): Optimize the
	support for them.

diff --git a/bfd/elfnn-aarch64.c b/bfd/elfnn-aarch64.c
index b61bb8a..4817e42 100644
--- a/bfd/elfnn-aarch64.c
+++ b/bfd/elfnn-aarch64.c
@@ -4907,6 +4907,18 @@ elfNN_aarch64_write_section (bfd *output_bfd  ATTRIBUTE_UNUSED,
   return FALSE;
 }
 
+/* Return TRUE if RELOC is a relocation against the base of GOT table.  */
+
+static bfd_boolean
+aarch64_relocation_aginst_gp_p (bfd_reloc_code_real_type reloc)
+{
+  return (reloc == BFD_RELOC_AARCH64_LD32_GOTPAGE_LO14
+	  || reloc == BFD_RELOC_AARCH64_LD64_GOTPAGE_LO15
+	  || reloc == BFD_RELOC_AARCH64_LD64_GOTOFF_LO15
+	  || reloc == BFD_RELOC_AARCH64_MOVW_GOTOFF_G0_NC
+	  || reloc == BFD_RELOC_AARCH64_MOVW_GOTOFF_G1);
+}
+
 /* Perform a relocation as part of a final link.  The input relocation type
    should be TLS relaxed.  */
 
@@ -5130,21 +5142,9 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto,
 						     value, output_bfd,
 						     unresolved_reloc_p);
 
-	  switch (bfd_r_type)
-	    {
-	    case BFD_RELOC_AARCH64_LD32_GOTPAGE_LO14:
-	    case BFD_RELOC_AARCH64_LD64_GOTPAGE_LO15:
-	      addend = (globals->root.sgot->output_section->vma
-			+ globals->root.sgot->output_offset);
-	      break;
-	    case BFD_RELOC_AARCH64_MOVW_GOTOFF_G0_NC:
-	    case BFD_RELOC_AARCH64_MOVW_GOTOFF_G1:
-	    case BFD_RELOC_AARCH64_LD64_GOTOFF_LO15:
-	      value = (value - globals->root.sgot->output_section->vma
-		       - globals->root.sgot->output_offset);
-	    default:
-	      break;
-	    }
+	  if (aarch64_relocation_aginst_gp_p (bfd_r_type))
+	    addend = (globals->root.sgot->output_section->vma
+		      + globals->root.sgot->output_offset);
 
 	  value = _bfd_aarch64_elf_resolve_relocation (bfd_r_type, place, value,
 						       addend, weak_undef_p);
@@ -5377,6 +5377,9 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto,
     case BFD_RELOC_AARCH64_LD32_GOT_LO12_NC:
     case BFD_RELOC_AARCH64_LD64_GOTPAGE_LO15:
     case BFD_RELOC_AARCH64_LD64_GOT_LO12_NC:
+    case BFD_RELOC_AARCH64_LD64_GOTOFF_LO15:
+    case BFD_RELOC_AARCH64_MOVW_GOTOFF_G0_NC:
+    case BFD_RELOC_AARCH64_MOVW_GOTOFF_G1:
       if (globals->root.sgot == NULL)
 	BFD_ASSERT (h != NULL);
 
@@ -5386,8 +5389,7 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto,
 	  value = aarch64_calculate_got_entry_vma (h, globals, info, value,
 						   output_bfd,
 						   unresolved_reloc_p);
-	  if (bfd_r_type == BFD_RELOC_AARCH64_LD64_GOTPAGE_LO15
-	      || bfd_r_type == BFD_RELOC_AARCH64_LD32_GOTPAGE_LO14)
+	  if (aarch64_relocation_aginst_gp_p (bfd_r_type))
 	    addend = (globals->root.sgot->output_section->vma
 		      + globals->root.sgot->output_offset);
 	  value = _bfd_aarch64_elf_resolve_relocation (bfd_r_type, place, value,
@@ -5446,81 +5448,12 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto,
 	   the direct data access into indirect data access through GOT.  */
 	value = got_entry_addr;
 
-	if (bfd_r_type == BFD_RELOC_AARCH64_LD64_GOTPAGE_LO15
-	    || bfd_r_type == BFD_RELOC_AARCH64_LD32_GOTPAGE_LO14)
+	if (aarch64_relocation_aginst_gp_p (bfd_r_type))
 	  addend = base_got->output_section->vma + base_got->output_offset;
 
 	value = _bfd_aarch64_elf_resolve_relocation (bfd_r_type, place, value,
 						     addend, weak_undef_p);
       }
-
-      break;
-
-    case BFD_RELOC_AARCH64_LD64_GOTOFF_LO15:
-    case BFD_RELOC_AARCH64_MOVW_GOTOFF_G0_NC:
-    case BFD_RELOC_AARCH64_MOVW_GOTOFF_G1:
-      if (h != NULL)
-	  value = aarch64_calculate_got_entry_vma (h, globals, info, value,
-						   output_bfd,
-						   unresolved_reloc_p);
-      else
-	{
-	  struct elf_aarch64_local_symbol *locals
-	    = elf_aarch64_locals (input_bfd);
-
-	  if (locals == NULL)
-	    {
-	      int howto_index = bfd_r_type - BFD_RELOC_AARCH64_RELOC_START;
-	      _bfd_error_handler
-		/* xgettext:c-format */
-		(_("%B: Local symbol descriptor table be NULL when applying "
-		   "relocation %s against local symbol"),
-		 input_bfd, elfNN_aarch64_howto_table[howto_index].name);
-	      abort ();
-	    }
-
-	  off = symbol_got_offset (input_bfd, h, r_symndx);
-	  base_got = globals->root.sgot;
-	  if (base_got == NULL)
-	    abort ();
-
-	  bfd_vma got_entry_addr = (base_got->output_section->vma
-				    + base_got->output_offset + off);
-
-	  if (!symbol_got_offset_mark_p (input_bfd, h, r_symndx))
-	    {
-	      bfd_put_64 (output_bfd, value, base_got->contents + off);
-
-	      if (bfd_link_pic (info))
-		{
-		  asection *s;
-		  Elf_Internal_Rela outrel;
-
-		  /* For local symbol, we have done absolute relocation in static
-		     linking stage.  While for share library, we need to update
-		     the content of GOT entry according to the share objects
-		     loading base address.  So we need to generate a
-		     R_AARCH64_RELATIVE reloc for dynamic linker.  */
-		  s = globals->root.srelgot;
-		  if (s == NULL)
-		    abort ();
-
-		  outrel.r_offset = got_entry_addr;
-		  outrel.r_info = ELFNN_R_INFO (0, AARCH64_R (RELATIVE));
-		  outrel.r_addend = value;
-		  elf_append_rela (output_bfd, s, &outrel);
-		}
-
-	      symbol_got_offset_mark (input_bfd, h, r_symndx);
-	    }
-	}
-
-      /* Update the relocation value to GOT entry addr as we have transformed
-	 the direct data access into indirect data access through GOT.  */
-      value = symbol_got_offset (input_bfd, h, r_symndx);
-      value = _bfd_aarch64_elf_resolve_relocation (bfd_r_type, place, value,
-						   0, weak_undef_p);
-      *unresolved_reloc_p = FALSE;
       break;
 
     case BFD_RELOC_AARCH64_TLSGD_ADD_LO12_NC:
diff --git a/bfd/elfxx-aarch64.c b/bfd/elfxx-aarch64.c
index 6c61ec6..10ee5fa 100644
--- a/bfd/elfxx-aarch64.c
+++ b/bfd/elfxx-aarch64.c
@@ -413,7 +413,6 @@ _bfd_aarch64_elf_resolve_relocation (bfd_reloc_code_real_type r_type,
 
     case BFD_RELOC_AARCH64_16:
     case BFD_RELOC_AARCH64_32:
-    case BFD_RELOC_AARCH64_LD64_GOTOFF_LO15:
     case BFD_RELOC_AARCH64_MOVW_G0:
     case BFD_RELOC_AARCH64_MOVW_G0_NC:
     case BFD_RELOC_AARCH64_MOVW_G0_S:
@@ -424,8 +423,6 @@ _bfd_aarch64_elf_resolve_relocation (bfd_reloc_code_real_type r_type,
     case BFD_RELOC_AARCH64_MOVW_G2_NC:
     case BFD_RELOC_AARCH64_MOVW_G2_S:
     case BFD_RELOC_AARCH64_MOVW_G3:
-    case BFD_RELOC_AARCH64_MOVW_GOTOFF_G0_NC:
-    case BFD_RELOC_AARCH64_MOVW_GOTOFF_G1:
     case BFD_RELOC_AARCH64_TLSDESC_OFF_G0_NC:
     case BFD_RELOC_AARCH64_TLSDESC_OFF_G1:
     case BFD_RELOC_AARCH64_TLSGD_MOVW_G0_NC:
@@ -468,10 +465,15 @@ _bfd_aarch64_elf_resolve_relocation (bfd_reloc_code_real_type r_type,
       value = PG (value + addend) - PG (place);
       break;
 
+    /* Caller must make sure addend is the base address of .got section.  */
     case BFD_RELOC_AARCH64_LD32_GOTPAGE_LO14:
     case BFD_RELOC_AARCH64_LD64_GOTPAGE_LO15:
-      /* Caller must make sure addend is the base address of .got section.  */
-      value = value - PG (addend);
+      addend = PG (addend);
+      /* Fall through.  */
+    case BFD_RELOC_AARCH64_LD64_GOTOFF_LO15:
+    case BFD_RELOC_AARCH64_MOVW_GOTOFF_G0_NC:
+    case BFD_RELOC_AARCH64_MOVW_GOTOFF_G1:
+      value = value - addend;
       break;
 
     case BFD_RELOC_AARCH64_ADD_LO12:

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