* bfd/bin-in.h (bfd_elf32_arm_set_target_relocs): Update prototype.

	* bfd/bin-in2.h (bfd_elf32_arm_set_target_relocs): Update prototype.
	* bfd/elf32-arm.c (elf32_arm_link_hash_table): Add fix_v4bx flag.
	(bfd_elf32_arm_set_target_relocs): Add formal parameter fix_v4bx for
	passing flag value from ld. Set flag value in global hash table entry.
	(elf32_arm_final_link_relocate): Add code to implement R_ARM_V4BX
	relocation.
	* ld/emultempl/armelf.em (fix_v4bx): New variable.
	(arm_elf_create_output_section_statements): Communicate fix_v4bx flag
	value to bfd.
	(PARSE_AND_LIST_PROLOGUE): Add option token OPTION_FIX_V4BX.
	(PARSE_AND_LIST_LONGOPTS): Add option --fix-v4bx.
	(PARSE_AND_LIST_OPTIONS): Add option --fix-v4bx.
	(PARSE_AND_LIST_ARGS_CASES): Add option OPTION_FIX_V4BX.
	* ld/NEWS: Mention --fix-v4bx.
	* ld/ld.texinfo: Document --fix-v4bx.

1 files changed, 22 insertions, 1 deletions

diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index 09b47d3..14f46f4 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -1165,6 +1165,9 @@ struct elf32_arm_link_hash_table
     /* The relocation to use for R_ARM_TARGET2 relocations.  */
     int target2_reloc;
 
+    /* Nonzero to fix BX instructions for ARMv4 targets.  */
+    int fix_v4bx;
+
     /* The number of bytes in the initial entry in the PLT.  */
     bfd_size_type plt_header_size;
 
@@ -1931,7 +1934,8 @@ error_return:
 void
 bfd_elf32_arm_set_target_relocs (struct bfd_link_info *link_info,
 				 int target1_is_rel,
-				 char * target2_type)
+				 char * target2_type,
+                                 int fix_v4bx)
 {
   struct elf32_arm_link_hash_table *globals;
 
@@ -1949,6 +1953,7 @@ bfd_elf32_arm_set_target_relocs (struct bfd_link_info *link_info,
       _bfd_error_handler (_("Invalid TARGET2 relocation type '%s'."),
 			  target2_type);
     }
+  globals->fix_v4bx = fix_v4bx;
 }
 #endif
 
@@ -2985,6 +2990,22 @@ elf32_arm_final_link_relocate (reloc_howto_type *           howto,
     case R_ARM_RBASE:
       return bfd_reloc_notsupported;
 
+    case R_ARM_V4BX:
+      if (globals->fix_v4bx)
+        {
+          bfd_vma insn = bfd_get_32 (input_bfd, hit_data);
+
+          /* Ensure that we have a BX instruction.  */
+          BFD_ASSERT ((insn & 0x0ffffff0) == 0x012fff10);
+
+          /* Preserve Rm (lowest four bits) and the condition code
+             (highest four bits). Other bits encode MOV PC,Rm.  */
+          insn = (insn & 0xf000000f) | 0x01a0f000;
+
+          bfd_put_32 (input_bfd, insn, hit_data);
+        }
+      return bfd_reloc_ok;
+
     default:
       return bfd_reloc_notsupported;
     }