MIPS: Convert cross-mode BAL to JALX

Convert cross-mode regular MIPS and microMIPS BAL instructions to JALX,
similarly to how JAL instructions are converted.

	bfd/
	* elfxx-mips.c (mips_elf_perform_relocation): Convert cross-mode
	BAL to JALX.
	(_bfd_mips_elf_relocate_section) <bfd_reloc_outofrange>: Add a
	corresponding error message.

	gas/
	* config/tc-mips.c (mips_force_relocation, mips_fix_adjustable):
	Adjust comments for BAL to JALX linker conversion.
	(fix_bad_cross_mode_branch_p): Accept cross-mode BAL.
	* testsuite/gas/mips/unaligned-branch-1.l: Update error messages
	expected.
	* testsuite/gas/mips/unaligned-branch-micromips-1.l: Likewise.
	* testsuite/gas/mips/branch-local-4.d: New test.
	* testsuite/gas/mips/branch-local-n32-4.d: New test.
	* testsuite/gas/mips/branch-local-n64-4.d: New test.
	* testsuite/gas/mips/branch-addend.d: New test.
	* testsuite/gas/mips/branch-addend-n32.d: New test.
	* testsuite/gas/mips/branch-addend-n64.d: New test.
	* testsuite/gas/mips/branch-local-4.s: New test source.
	* testsuite/gas/mips/branch-addend.s: New test source.
	* testsuite/gas/mips/mips.exp: Run the new tests.

	ld/
	* testsuite/ld-mips-elf/unaligned-branch-2.d: Update error
	messages expected.
	* testsuite/ld-mips-elf/unaligned-branch-r6-1.d: Likewise.
	* testsuite/ld-mips-elf/unaligned-branch-mips16.d: Likewise.
	* testsuite/ld-mips-elf/unaligned-branch-micromips.d: Likewise.
	* testsuite/ld-mips-elf/bal-jalx-addend.d: New test.
	* testsuite/ld-mips-elf/bal-jalx-local.d: New test.
	* testsuite/ld-mips-elf/bal-jalx-pic.d: New test.
	* testsuite/ld-mips-elf/bal-jalx-addend-n32.d: New test.
	* testsuite/ld-mips-elf/bal-jalx-local-n32.d: New test.
	* testsuite/ld-mips-elf/bal-jalx-pic-n32.d: New test.
	* testsuite/ld-mips-elf/bal-jalx-addend-n64.d: New test.
	* testsuite/ld-mips-elf/bal-jalx-local-n64.d: New test.
	* testsuite/ld-mips-elf/bal-jalx-pic-n64.d: New test.
	* testsuite/ld-mips-elf/unaligned-jalx-2.d: New test.
	* testsuite/ld-mips-elf/unaligned-jalx-3.d: New test.
	* testsuite/ld-mips-elf/unaligned-jalx-addend-2.d: New test.
	* testsuite/ld-mips-elf/unaligned-jalx-addend-3.d: New test.
	* testsuite/ld-mips-elf/unaligned-jalx-2.s: New test source.
	* testsuite/ld-mips-elf/unaligned-jalx-3.s: New test source.
	* testsuite/ld-mips-elf/unaligned-jalx-addend-2.s: New test
	source.
	* testsuite/ld-mips-elf/unaligned-jalx-addend-3.s: New test
	source.
	* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.

2 files changed, 56 insertions, 6 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index bb4103f..738f81d 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,5 +1,12 @@
 2016-07-19  Maciej W. Rozycki  <macro@imgtec.com>
 
+	* elfxx-mips.c (mips_elf_perform_relocation): Convert cross-mode
+	BAL to JALX.
+	(_bfd_mips_elf_relocate_section) <bfd_reloc_outofrange>: Add a
+	corresponding error message.
+
+2016-07-19  Maciej W. Rozycki  <macro@imgtec.com>
+
 	* elfxx-mips.c (b_reloc_p): Add R_MICROMIPS_PC16_S1,
 	R_MICROMIPS_PC10_S1 and R_MICROMIPS_PC7_S1.
 	(branch_reloc_p): New function.
diff --git a/bfd/elfxx-mips.c b/bfd/elfxx-mips.c
index fa99c9d..5dcbcf9 100644
--- a/bfd/elfxx-mips.c
+++ b/bfd/elfxx-mips.c
@@ -6339,7 +6339,7 @@ mips_elf_perform_relocation (struct bfd_link_info *info,
   /* Set the field.  */
   x |= (value & howto->dst_mask);
 
-  /* Detect incorrect JALX usage.  If required, turn JAL into JALX.  */
+  /* Detect incorrect JALX usage.  If required, turn JAL or BAL into JALX.  */
   if (!cross_mode_jump_p && jal_reloc_p (r_type))
     {
       bfd_vma opcode = x >> 26;
@@ -6393,10 +6393,50 @@ mips_elf_perform_relocation (struct bfd_link_info *info,
     }
   else if (cross_mode_jump_p && b_reloc_p (r_type))
     {
-      info->callbacks->einfo
-	(_("%X%H: Unsupported branch between ISA modes\n"),
-	 input_bfd, input_section, relocation->r_offset);
-      return TRUE;
+      bfd_boolean ok = FALSE;
+      bfd_vma opcode = x >> 16;
+      bfd_vma jalx_opcode = 0;
+      bfd_vma addr;
+      bfd_vma dest;
+
+      if (r_type == R_MICROMIPS_PC16_S1)
+	{
+	  ok = opcode == 0x4060;
+	  jalx_opcode = 0x3c;
+	  value <<= 1;
+	}
+      else if (r_type == R_MIPS_PC16 || r_type == R_MIPS_GNU_REL16_S2)
+	{
+	  ok = opcode == 0x411;
+	  jalx_opcode = 0x1d;
+	  value <<= 2;
+	}
+
+      if (bfd_link_pic (info) || !ok)
+	{
+	  info->callbacks->einfo
+	    (_("%X%H: Unsupported branch between ISA modes\n"),
+	     input_bfd, input_section, relocation->r_offset);
+	  return TRUE;
+	}
+
+      addr = (input_section->output_section->vma
+	      + input_section->output_offset
+	      + relocation->r_offset
+	      + 4);
+      dest = addr + (((value & 0x3ffff) ^ 0x20000) - 0x20000);
+
+      if ((addr >> 28) << 28 != (dest >> 28) << 28)
+	{
+	  info->callbacks->einfo
+	    (_("%X%H: Cannot convert branch between ISA modes "
+	       "to JALX: relocation out of range\n"),
+	     input_bfd, input_section, relocation->r_offset);
+	  return TRUE;
+	}
+
+      /* Make this the JALX opcode.  */
+      x = ((dest >> 2) & 0x3ffffff) | jalx_opcode << 26;
     }
 
   /* Try converting JAL to BAL and J(AL)R to B(AL), if the target is in
@@ -10390,7 +10430,10 @@ _bfd_mips_elf_relocate_section (bfd *output_bfd, struct bfd_link_info *info,
 		      ? _("Jump to a non-word-aligned address")
 		      : _("Jump to a non-instruction-aligned address")));
 	  else if (b_reloc_p (howto->type))
-	    msg = _("Branch to a non-instruction-aligned address");
+	    msg = (cross_mode_jump_p
+		   ? _("Cannot convert a branch to JALX "
+		       "for a non-word-aligned address")
+		   : _("Branch to a non-instruction-aligned address"));
 	  else if (aligned_pcrel_reloc_p (howto->type))
 	    msg = _("PC-relative load from unaligned address");
 	  if (msg)