[ARM] Add support for thumb1 pcrop relocations.

To support thumb1 execute-only code we need to support four new
relocations (R_ARM_THM_ALU_ABS_G0_NC, R_ARM_THM_ALU_ABS_G1_NC,
R_ARM_THM_ALU_ABS_G2_NC and  R_ARM_THM_ALU_ABS_G3_NC).
These relocations allow the static linker to finalize construction
of symbol address.
Typical sequence of code to get address of the symbol foo is then
the following :
	movs	r3, #:upper8_15:#foo
	lsls	r3, #8
	adds	r3, #:upper0_7:#foo
	lsls	r3, #8
	adds	r3, #:lower8_15:#foo
	lsls	r3, #8
	adds	r3, #:lower0_7:#foo
This will give following sequence of text and relocations after
assembly :
   4:	2300      	movs	r3, #0
			4: R_ARM_THM_ALU_ABS_G3_NC	foo
   6:	021b      	lsls	r3, r3, #8
   8:	3300      	adds	r3, #0
			8: R_ARM_THM_ALU_ABS_G2_NC	foo
   a:	021b      	lsls	r3, r3, #8
   c:	3300      	adds	r3, #0
			c: R_ARM_THM_ALU_ABS_G1_NC	foo
   e:	021b      	lsls	r3, r3, #8
  10:	3300      	adds	r3, #0
			10: R_ARM_THM_ALU_ABS_G0_NC	foo

4 files changed, 107 insertions, 1 deletions

diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index 606d11b..39eb19a 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -3516,6 +3516,12 @@ pc-relative or some form of GOT-indirect relocation.  */
 /* ARM support for STT_GNU_IFUNC.  */
   BFD_RELOC_ARM_IRELATIVE,
 
+/* Thumb1 relocations to support execute-only code.  */
+  BFD_RELOC_ARM_THUMB_ALU_ABS_G0_NC,
+  BFD_RELOC_ARM_THUMB_ALU_ABS_G1_NC,
+  BFD_RELOC_ARM_THUMB_ALU_ABS_G2_NC,
+  BFD_RELOC_ARM_THUMB_ALU_ABS_G3_NC,
+
 /* These relocs are only used within the ARM assembler.  They are not
 (at present) written to any object files.  */
   BFD_RELOC_ARM_IMMEDIATE,
diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index 49dfc53..49d6469 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -1689,6 +1689,60 @@ static reloc_howto_type elf32_arm_howto_table_1[] =
 	 0x00000000,		/* src_mask */
 	 0x00000000,		/* dst_mask */
 	 FALSE),		/* pcrel_offset */
+  EMPTY_HOWTO (130),
+  EMPTY_HOWTO (131),
+  HOWTO (R_ARM_THM_ALU_ABS_G0_NC,/* type.  */
+	 0,			/* rightshift.  */
+	 1,			/* size (0 = byte, 1 = short, 2 = long).  */
+	 16,			/* bitsize.  */
+	 FALSE,			/* pc_relative.  */
+	 0,			/* bitpos.  */
+	 complain_overflow_bitfield,/* complain_on_overflow.  */
+	 bfd_elf_generic_reloc,	/* special_function.  */
+	 "R_ARM_THM_ALU_ABS_G0_NC",/* name.  */
+	 FALSE,			/* partial_inplace.  */
+	 0x00000000,		/* src_mask.  */
+	 0x00000000,		/* dst_mask.  */
+	 FALSE),		/* pcrel_offset.  */
+  HOWTO (R_ARM_THM_ALU_ABS_G1_NC,/* type.  */
+	 0,			/* rightshift.  */
+	 1,			/* size (0 = byte, 1 = short, 2 = long).  */
+	 16,			/* bitsize.  */
+	 FALSE,			/* pc_relative.  */
+	 0,			/* bitpos.  */
+	 complain_overflow_bitfield,/* complain_on_overflow.  */
+	 bfd_elf_generic_reloc,	/* special_function.  */
+	 "R_ARM_THM_ALU_ABS_G1_NC",/* name.  */
+	 FALSE,			/* partial_inplace.  */
+	 0x00000000,		/* src_mask.  */
+	 0x00000000,		/* dst_mask.  */
+	 FALSE),		/* pcrel_offset.  */
+  HOWTO (R_ARM_THM_ALU_ABS_G2_NC,/* type.  */
+	 0,			/* rightshift.  */
+	 1,			/* size (0 = byte, 1 = short, 2 = long).  */
+	 16,			/* bitsize.  */
+	 FALSE,			/* pc_relative.  */
+	 0,			/* bitpos.  */
+	 complain_overflow_bitfield,/* complain_on_overflow.  */
+	 bfd_elf_generic_reloc,	/* special_function.  */
+	 "R_ARM_THM_ALU_ABS_G2_NC",/* name.  */
+	 FALSE,			/* partial_inplace.  */
+	 0x00000000,		/* src_mask.  */
+	 0x00000000,		/* dst_mask.  */
+	 FALSE),		/* pcrel_offset.  */
+  HOWTO (R_ARM_THM_ALU_ABS_G3_NC,/* type.  */
+	 0,			/* rightshift.  */
+	 1,			/* size (0 = byte, 1 = short, 2 = long).  */
+	 16,			/* bitsize.  */
+	 FALSE,			/* pc_relative.  */
+	 0,			/* bitpos.  */
+	 complain_overflow_bitfield,/* complain_on_overflow.  */
+	 bfd_elf_generic_reloc,	/* special_function.  */
+	 "R_ARM_THM_ALU_ABS_G3_NC",/* name.  */
+	 FALSE,			/* partial_inplace.  */
+	 0x00000000,		/* src_mask.  */
+	 0x00000000,		/* dst_mask.  */
+	 FALSE),		/* pcrel_offset.  */
 };
 
 /* 160 onwards: */
@@ -1889,7 +1943,11 @@ static const struct elf32_arm_reloc_map elf32_arm_reloc_map[] =
     {BFD_RELOC_ARM_LDC_SB_G0, R_ARM_LDC_SB_G0},
     {BFD_RELOC_ARM_LDC_SB_G1, R_ARM_LDC_SB_G1},
     {BFD_RELOC_ARM_LDC_SB_G2, R_ARM_LDC_SB_G2},
-    {BFD_RELOC_ARM_V4BX,	     R_ARM_V4BX}
+    {BFD_RELOC_ARM_V4BX,	     R_ARM_V4BX},
+    {BFD_RELOC_ARM_THUMB_ALU_ABS_G3_NC, R_ARM_THM_ALU_ABS_G3_NC},
+    {BFD_RELOC_ARM_THUMB_ALU_ABS_G2_NC, R_ARM_THM_ALU_ABS_G2_NC},
+    {BFD_RELOC_ARM_THUMB_ALU_ABS_G1_NC, R_ARM_THM_ALU_ABS_G1_NC},
+    {BFD_RELOC_ARM_THUMB_ALU_ABS_G0_NC, R_ARM_THM_ALU_ABS_G0_NC}
   };
 
 static reloc_howto_type *
@@ -11023,6 +11081,33 @@ elf32_arm_final_link_relocate (reloc_howto_type *           howto,
       }
       return bfd_reloc_ok;
 
+    case R_ARM_THM_ALU_ABS_G0_NC:
+    case R_ARM_THM_ALU_ABS_G1_NC:
+    case R_ARM_THM_ALU_ABS_G2_NC:
+    case R_ARM_THM_ALU_ABS_G3_NC:
+	{
+	    const int shift_array[4] = {0, 8, 16, 24};
+	    bfd_vma insn = bfd_get_16 (input_bfd, hit_data);
+	    bfd_vma addr = value;
+	    int shift = shift_array[r_type - R_ARM_THM_ALU_ABS_G0_NC];
+
+	    /* Compute address.  */
+	    if (globals->use_rel)
+		signed_addend = insn & 0xff;
+	    addr += signed_addend;
+	    if (branch_type == ST_BRANCH_TO_THUMB)
+		addr |= 1;
+	    /* Clean imm8 insn.  */
+	    insn &= 0xff00;
+	    /* And update with correct part of address.  */
+	    insn |= (addr >> shift) & 0xff;
+	    /* Update insn.  */
+	    bfd_put_16 (input_bfd, insn, hit_data);
+	}
+
+	*unresolved_reloc_p = FALSE;
+	return bfd_reloc_ok;
+
     default:
       return bfd_reloc_notsupported;
     }
diff --git a/bfd/libbfd.h b/bfd/libbfd.h
index 1c93c91..8765bee 100644
--- a/bfd/libbfd.h
+++ b/bfd/libbfd.h
@@ -1545,6 +1545,10 @@ static const char *const bfd_reloc_code_real_names[] = { "@@uninitialized@@",
   "BFD_RELOC_ARM_LDC_SB_G2",
   "BFD_RELOC_ARM_V4BX",
   "BFD_RELOC_ARM_IRELATIVE",
+  "BFD_RELOC_ARM_THUMB_ALU_ABS_G0_NC",
+  "BFD_RELOC_ARM_THUMB_ALU_ABS_G1_NC",
+  "BFD_RELOC_ARM_THUMB_ALU_ABS_G2_NC",
+  "BFD_RELOC_ARM_THUMB_ALU_ABS_G3_NC",
   "BFD_RELOC_ARM_IMMEDIATE",
   "BFD_RELOC_ARM_ADRL_IMMEDIATE",
   "BFD_RELOC_ARM_T32_IMMEDIATE",
diff --git a/bfd/reloc.c b/bfd/reloc.c
index 593e7c7..869503c 100644
--- a/bfd/reloc.c
+++ b/bfd/reloc.c
@@ -3272,6 +3272,17 @@ ENUMDOC
   ARM support for STT_GNU_IFUNC.
 
 ENUM
+  BFD_RELOC_ARM_THUMB_ALU_ABS_G0_NC
+ENUMX
+  BFD_RELOC_ARM_THUMB_ALU_ABS_G1_NC
+ENUMX
+  BFD_RELOC_ARM_THUMB_ALU_ABS_G2_NC
+ENUMX
+  BFD_RELOC_ARM_THUMB_ALU_ABS_G3_NC
+ENUMDOC
+  Thumb1 relocations to support execute-only code.
+
+ENUM
   BFD_RELOC_ARM_IMMEDIATE
 ENUMX
   BFD_RELOC_ARM_ADRL_IMMEDIATE