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

	* bfd/bfd-in2.h: Regenerate.
	* bfd/elf32-arm.c (elf32_arm_link_hash_table): New field, 'use_blx'.
	(elf32_arm_link_hash_table_create): Initialise fix_v4bx, use_blx.
	(bfd_elf32_arm_set_target_relocs): Handle use_blx.
	(elf32_arm_final_link_relocate): Use Thumb BLX for R_ARM_THM_PC22
	relocations if requested to.
	(allocate_dynrelocs): Don't count size of omitted Thumb stubs based on
	use_blx rather than symbian_p.
	(elf32_arm_finish_dynamic_symbol): Don't output Thumb PLT stubs if
	use_blx is in effect.
	(elf32_arm_symbian_link_hash_table_create): Enable use_blx by default
	for SymbianOS.
	* ld/ld.texinfo: Document --use-blx.
	* ld/emultempl/armelf.em (use_blx): New variable.
	(arm_elf_create_output_section_statements): Communicate value of
	use_blx to bfd.
	(PARSE_AND_LIST_PROLOGUE): Add OPTION_USE_BLX.
	(PARSE_AND_LIST_OPTIONS): Add --use-blx option.
	(PARSE_AND_LIST_ARGS_CASES): Add OPTION_USE_BLX case.

7 files changed, 78 insertions, 11 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 35ac02d..2ec4601 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,19 @@
+2004-04-15  Julian Brown  <julian@codesourcery.com>
+
+	* bfd-in.h (bfd_elf32_arm_set_target_relocs): Update prototype.
+	* bfd-in2.h: Regenerate.
+	* elf32-arm.c (elf32_arm_link_hash_table): New field, 'use_blx'.
+	(elf32_arm_link_hash_table_create): Initialise fix_v4bx, use_blx.
+	(bfd_elf32_arm_set_target_relocs): Handle use_blx.
+	(elf32_arm_final_link_relocate): Use Thumb BLX for R_ARM_THM_PC22
+	relocations if requested to.
+	(allocate_dynrelocs): Don't count size of omitted Thumb stubs based on
+	use_blx rather than symbian_p.
+	(elf32_arm_finish_dynamic_symbol): Don't output Thumb PLT stubs if
+	use_blx is in effect.
+	(elf32_arm_symbian_link_hash_table_create): Enable use_blx by default
+	for SymbianOS.
+
 2005-04-15  Nick Clifton  <nickc@redhat.com>
 
 	* coffgen.c (coff_print_symbol): Use fprintf_vma to print vma
diff --git a/bfd/bfd-in.h b/bfd/bfd-in.h
index a3dedb5..90e123d9 100644
--- a/bfd/bfd-in.h
+++ b/bfd/bfd-in.h
@@ -816,7 +816,7 @@ extern bfd_boolean bfd_elf32_arm_process_before_allocation
   (bfd *, struct bfd_link_info *, int);
 
 void bfd_elf32_arm_set_target_relocs
-  (struct bfd_link_info *, int, char *, int);
+  (struct bfd_link_info *, int, char *, int, int);
 
 extern bfd_boolean bfd_elf32_arm_get_bfd_for_interworking
   (bfd *, struct bfd_link_info *);
diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index bed224d..1e373f2 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -823,7 +823,7 @@ extern bfd_boolean bfd_elf32_arm_process_before_allocation
   (bfd *, struct bfd_link_info *, int);
 
 void bfd_elf32_arm_set_target_relocs
-  (struct bfd_link_info *, int, char *, int);
+  (struct bfd_link_info *, int, char *, int, int);
 
 extern bfd_boolean bfd_elf32_arm_get_bfd_for_interworking
   (bfd *, struct bfd_link_info *);
diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index a46713d..ef31740 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -1324,6 +1324,9 @@ struct elf32_arm_link_hash_table
     /* Nonzero to fix BX instructions for ARMv4 targets.  */
     int fix_v4bx;
 
+    /* Nonzero if the ARM/Thumb BLX instructions are available for use.  */
+    int use_blx;
+
     /* The number of bytes in the initial entry in the PLT.  */
     bfd_size_type plt_header_size;
 
@@ -1559,6 +1562,8 @@ elf32_arm_link_hash_table_create (bfd *abfd)
   ret->plt_header_size = 20;
   ret->plt_entry_size = 12;
 #endif
+  ret->fix_v4bx = 0;
+  ret->use_blx = 0;
   ret->symbian_p = 0;
   ret->use_rel = 1;
   ret->sym_sec.abfd = NULL;
@@ -2125,7 +2130,8 @@ void
 bfd_elf32_arm_set_target_relocs (struct bfd_link_info *link_info,
 				 int target1_is_rel,
 				 char * target2_type,
-                                 int fix_v4bx)
+                                 int fix_v4bx,
+				 int use_blx)
 {
   struct elf32_arm_link_hash_table *globals;
 
@@ -2144,6 +2150,7 @@ bfd_elf32_arm_set_target_relocs (struct bfd_link_info *link_info,
 			  target2_type);
     }
   globals->fix_v4bx = fix_v4bx;
+  globals->use_blx |= use_blx;
 }
 #endif
 
@@ -2893,6 +2900,7 @@ elf32_arm_final_link_relocate (reloc_howto_type *           howto,
 	bfd_signed_vma reloc_signed_min = ~ reloc_signed_max;
 	bfd_vma check;
 	bfd_signed_vma signed_check;
+	bfd_boolean thumb_plt_call = FALSE;
 
 	/* Need to refetch the addend and squish the two 11 bit pieces
 	   together.  */
@@ -2942,8 +2950,19 @@ elf32_arm_final_link_relocate (reloc_howto_type *           howto,
 	    value = (splt->output_section->vma
 		     + splt->output_offset
 		     + h->plt.offset);
-	    /* Target the Thumb stub before the ARM PLT entry.  */
-	    value -= 4;
+ 	    if (globals->use_blx)
+ 	      {
+ 		/* If the Thumb BLX instruction is available, convert the
+		   BL to a BLX instruction to call the ARM-mode PLT entry.  */
+ 		if ((lower_insn & (0x3 << 11)) == 0x3 << 11)
+		  {
+		    lower_insn = (lower_insn & ~(0x3 << 11)) | 0x1 << 11;
+		    thumb_plt_call = TRUE;
+		  }
+ 	      }
+ 	    else
+ 	      /* Target the Thumb stub before the ARM PLT entry.  */
+ 	      value -= PLT_THUMB_STUB_SIZE;
 	    *unresolved_reloc_p = FALSE;
 	  }
 
@@ -2967,8 +2986,9 @@ elf32_arm_final_link_relocate (reloc_howto_type *           howto,
 	  overflow = TRUE;
 
 #ifndef OLD_ARM_ABI
-	if (r_type == R_ARM_THM_XPC22
-	    && ((lower_insn & 0x1800) == 0x0800))
+	if ((r_type == R_ARM_THM_XPC22
+	     && ((lower_insn & 0x1800) == 0x0800))
+	    || thumb_plt_call)
 	  /* For a BLX instruction, make sure that the relocation is rounded up
 	     to a word boundary.  This follows the semantics of the instruction
 	     which specifies that bit 1 of the target address will come from bit
@@ -5059,7 +5079,7 @@ allocate_dynrelocs (struct elf_link_hash_entry *h, void * inf)
 
 	  /* If we will insert a Thumb trampoline before this PLT, leave room
 	     for it.  */
-	  if (!htab->symbian_p && eh->plt_thumb_refcount > 0)
+	  if (!htab->use_blx && eh->plt_thumb_refcount > 0)
 	    {
 	      h->plt.offset += PLT_THUMB_STUB_SIZE;
 	      s->size += PLT_THUMB_STUB_SIZE;
@@ -5632,7 +5652,7 @@ elf32_arm_finish_dynamic_symbol (bfd * output_bfd, struct bfd_link_info * info,
 
 	  BFD_ASSERT ((got_displacement & 0xf0000000) == 0);
 
-	  if (eh->plt_thumb_refcount > 0)
+	  if (!htab->use_blx && eh->plt_thumb_refcount > 0)
 	    {
 	      bfd_put_16 (output_bfd, elf32_arm_plt_thumb_stub[0],
 			  splt->contents + h->plt.offset - 4);
@@ -6505,6 +6525,8 @@ elf32_arm_symbian_link_hash_table_create (bfd *abfd)
       /* The PLT entries are each three instructions.  */
       htab->plt_entry_size = 4 * NUM_ELEM (elf32_arm_symbian_plt_entry);
       htab->symbian_p = 1;
+      /* Symbian uses armv5t or above, so use_blx is always true.  */
+      htab->use_blx = 1;
       htab->root.is_relocatable_executable = 1;
     }
   return ret;
diff --git a/ld/ChangeLog b/ld/ChangeLog
index 36fba51..3af8c71 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,13 @@
+2005-04-15  Julian Brown  <julian@codesourcery.com>
+
+	* ld.texinfo: Document --use-blx.
+	* emultempl/armelf.em (use_blx): New variable.
+	(arm_elf_create_output_section_statements): Communicate value of
+	use_blx to bfd.
+	(PARSE_AND_LIST_PROLOGUE): Add OPTION_USE_BLX.
+	(PARSE_AND_LIST_OPTIONS): Add --use-blx option.
+	(PARSE_AND_LIST_ARGS_CASES): Add OPTION_USE_BLX case.
+
 2005-04-14  Alan Modra  <amodra@bigpond.net.au>
 
 	* Makefile.am (NO_WERROR): Define.  Use instead of -Wno-error.
diff --git a/ld/emultempl/armelf.em b/ld/emultempl/armelf.em
index 886cf8b..d380400 100644
--- a/ld/emultempl/armelf.em
+++ b/ld/emultempl/armelf.em
@@ -32,6 +32,7 @@ static int byteswap_code = 0;
 static int target1_is_rel = 0${TARGET1_IS_REL};
 static char *target2_type = "${TARGET2_TYPE}";
 static int fix_v4bx = 0;
+static int use_blx = 0;
 
 static void
 gld${EMULATION_NAME}_before_parse (void)
@@ -192,7 +193,7 @@ static void
 arm_elf_create_output_section_statements (void)
 {
   bfd_elf32_arm_set_target_relocs (&link_info, target1_is_rel, target2_type,
-                                   fix_v4bx);
+                                   fix_v4bx, use_blx);
 }
 
 EOF
@@ -206,7 +207,8 @@ PARSE_AND_LIST_PROLOGUE='
 #define OPTION_TARGET1_REL		303
 #define OPTION_TARGET1_ABS		304
 #define OPTION_TARGET2			305
-#define OPTION_FIX_V4BX                 306
+#define OPTION_FIX_V4BX			306
+#define OPTION_USE_BLX			307
 '
 
 PARSE_AND_LIST_SHORTOPTS=p
@@ -219,6 +221,7 @@ PARSE_AND_LIST_LONGOPTS='
   { "target1-abs", no_argument, NULL, OPTION_TARGET1_ABS},
   { "target2", required_argument, NULL, OPTION_TARGET2},
   { "fix-v4bx", no_argument, NULL, OPTION_FIX_V4BX},
+  { "use-blx", no_argument, NULL, OPTION_USE_BLX},
 '
 
 PARSE_AND_LIST_OPTIONS='
@@ -228,6 +231,7 @@ PARSE_AND_LIST_OPTIONS='
   fprintf (file, _("     --target1=abs            Interpret R_ARM_TARGET1 as R_ARM_ABS32\n"));
   fprintf (file, _("     --target2=<type>         Specify definition of R_ARM_TARGET2\n"));
   fprintf (file, _("     --fix-v4bx               Rewrite BX rn as MOV pc, rn for ARMv4\n"));
+  fprintf (file, _("     --use-blx                Enable use of BLX instructions\n"));
 '
 
 PARSE_AND_LIST_ARGS_CASES='
@@ -258,6 +262,10 @@ PARSE_AND_LIST_ARGS_CASES='
     case OPTION_FIX_V4BX:
       fix_v4bx = 1;
       break;
+
+    case OPTION_USE_BLX:
+      use_blx = 1;
+      break;
 '
 
 # We have our own after_open and before_allocation functions, but they call
diff --git a/ld/ld.texinfo b/ld/ld.texinfo
index 99afaf2..7860e25 100644
--- a/ld/ld.texinfo
+++ b/ld/ld.texinfo
@@ -5262,6 +5262,17 @@ linker, which causes v4t @code{BX rM} instructions to be rewritten as
 In the former case, the switch should not be used, and @samp{R_ARM_V4BX}
 relocations are ignored.
 
+@cindex USE_BLX
+@kindex --use-blx
+The @samp{--use-blx} switch enables the linker to use ARM/Thumb
+BLX instructions (available on ARMv5t and above) in various
+situations. Currently it is used to perform calls via the PLT from Thumb
+code using BLX rather than using BX and a mode-switching stub before
+each PLT entry. This should lead to such calls executing slightly faster.
+
+This option is enabled implicitly for SymbianOS, so there is no need to
+specify it if you are using that target.
+
 @ifclear GENERIC
 @lowersections
 @end ifclear