[PATCH, binutils, ARM, 5/16] BF insns infrastructure with new global reloc R_ARM_THM_BF16

["Andre Vieira (lists)" <andre.simoesdiasvieira@arm.com>]

[-- Attachment #1: Type: text/plain, Size: 1848 bytes --]

Hi

This patch is part of a series of patches to add support for Armv8.1-M 
Mainline instructions to binutils.
This adds infrastructure for the BF instructions which is one of the 
first instructions in Arm that
have more than one relocations in them.

This is the third infrastructure patch that adds a new relocation 
R_ARM_THM_BF16. Relocation specified in 
https://developer.arm.com/docs/ihi0044/latest/elf-for-the-arm-architecture-abi-2019q1-documentation#aaelf32-table4-9

The inconsistency between external R_ARM_THM_BF16 and internal 
BFD_RELOC_ARM_THUMB_BF17 is because internally we count the static bit-0 
of the immediate and we don't externally.

Testing: Builds successfully and no regressions.

Thanks
Sudi


ChangeLog entries are as follows :

*** bfd/ChnageLog ***

2019-04-04  Sudakshina Das  <sudi.das@arm.com>

	* reloc.c (BFD_RELOC_ARM_THUMB_BF17): New enum.
	* bfd-in2.h: Regenerated.
	* libbfd.h: Regenerated.
	* bfd-elf32-arm.c (elf32_arm_howto_table_1): New entry for R_ARM_THM_BF16.
	(elf32_arm_reloc_map elf32_arm_reloc_map): Map BFD_RELOC_ARM_THUMB_BF17
	and R_ARM_THM_BF16 together.
	(get_value_helper): New reloc helper.
	(elf32_arm_final_link_relocate): New switch case for R_ARM_THM_BF16.

*** elfcpp/ChangeLog ***

2019-04-04  Sudakshina Das  <sudi.das@arm.com>

	* arm.h (R_ARM_THM_BF16): New relocation code.

*** gas/ChangeLog ***

2019-04-04  Sudakshina Das  <sudi.das@arm.com>

	* config/tc-arm.c (md_pcrel_from_section): New switch case for
	BFD_RELOC_ARM_THUMB_BF17.
	(md_appdy_fix): Likewise.
	(tc_gen_reloc): Likewise.

*** include/ChangeLog ***

2019-04-04  Sudakshina Das  <sudi.das@arm.com>

	* elf/arm.h (START_RELOC_NUMBERS): New entry for R_ARM_THM_BF16.

*** opcodes/ChangeLog ***

2019-04-04  Sudakshina Das  <sudi.das@arm.com>

	* arm-dis.c (print_insn_thumb32): Updated to accept new %W pattern.

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 5.patch --]
[-- Type: text/x-patch; name="5.patch", Size: 10716 bytes --]

diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index 3493d4f0de41cb184710248ce6664700bca78cca..b5922ff222b48e0699a814c9742e0a61cdca9cb8 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -3567,6 +3567,9 @@ field in the instruction.  */
 /* ARM 5-bit pc-relative branch for Branch Future instructions.  */
   BFD_RELOC_THUMB_PCREL_BRANCH5,
 
+/* ARM 17-bit pc-relative branch for Branch Future instructions.  */
+  BFD_RELOC_ARM_THUMB_BF17,
+
 /* Thumb 7-, 9-, 12-, 20-, 23-, and 25-bit pc-relative branches.
 The lowest bit must be zero and is not stored in the instruction.
 Note that the corresponding ELF R_ARM_THM_JUMPnn constant has an
diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index 735fe122880c59633b0083b78b9b1e686cfd91c5..abdc2bbdac6f00e7ce631bcb1dfa477edf480063 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -1742,6 +1742,20 @@ static reloc_howto_type elf32_arm_howto_table_1[] =
 	 0x00000000,		/* src_mask.  */
 	 0x00000000,		/* dst_mask.  */
 	 FALSE),		/* pcrel_offset.  */
+  /* Relocations for Armv8.1-M Mainline.  */
+  HOWTO (R_ARM_THM_BF16,	/* type.  */
+	 0,			/* rightshift.  */
+	 1,			/* size (0 = byte, 1 = short, 2 = long).  */
+	 16,			/* bitsize.  */
+	 TRUE,			/* pc_relative.  */
+	 0,			/* bitpos.  */
+	 complain_overflow_dont,/* do not complain_on_overflow.  */
+	 bfd_elf_generic_reloc,	/* special_function.  */
+	 "R_ARM_THM_BF16",	/* name.  */
+	 FALSE,			/* partial_inplace.  */
+	 0x001f0ffe,		/* src_mask.  */
+	 0x001f0ffe,		/* dst_mask.  */
+	 TRUE),			/* pcrel_offset.  */
 };
 
 /* 160 onwards: */
@@ -2053,7 +2067,8 @@ static const struct elf32_arm_reloc_map elf32_arm_reloc_map[] =
     {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}
+    {BFD_RELOC_ARM_THUMB_ALU_ABS_G0_NC, R_ARM_THM_ALU_ABS_G0_NC},
+    {BFD_RELOC_ARM_THUMB_BF17, R_ARM_THM_BF16}
   };
 
 static reloc_howto_type *
@@ -10250,6 +10265,59 @@ identify_add_or_sub (bfd_vma insn)
   return 0;
 }
 
+/* Helper function to compute the Addend for Armv8.1-M Mainline relocations.  */
+static bfd_vma
+get_value_helper (bfd_vma plt_offset,
+		  asection *splt,
+		  asection *input_section,
+		  asection *sym_sec,
+		  struct elf_link_hash_entry * h,
+		  struct bfd_link_info *info,
+		  bfd *input_bfd,
+		  Elf_Internal_Rela *rel,
+		  const char *sym_name,
+		  unsigned char st_type,
+		  struct elf32_arm_link_hash_table *globals,
+		  bfd_boolean *unresolved_reloc_p)
+{
+  bfd_vma value = 0;
+  enum arm_st_branch_type branch_type;
+  enum elf32_arm_stub_type stub_type = arm_stub_none;
+  struct elf32_arm_stub_hash_entry *stub_entry;
+  struct elf32_arm_link_hash_entry *hash
+    = (struct elf32_arm_link_hash_entry *)h;
+
+
+  if (plt_offset != (bfd_vma) -1)
+    {
+      value = (splt->output_section->vma
+	       + splt->output_offset
+	       + plt_offset);
+      value -= PLT_THUMB_STUB_SIZE;
+      *unresolved_reloc_p = FALSE;
+    }
+
+  stub_type = arm_type_of_stub (info, input_section, rel,
+				st_type, &branch_type,
+				hash, value, sym_sec,
+				input_bfd, sym_name);
+
+  if (stub_type != arm_stub_none)
+    {
+      stub_entry = elf32_arm_get_stub_entry (input_section,
+					     sym_sec, h,
+					     rel, globals,
+					     stub_type);
+	    if (stub_entry != NULL)
+	      {
+		value = (stub_entry->stub_offset
+			 + stub_entry->stub_sec->output_offset
+			 + stub_entry->stub_sec->output_section->vma);
+	      }
+	  }
+  return value;
+}
+
 /* Perform a relocation as part of a final link.  */
 
 static bfd_reloc_status_type
@@ -12855,6 +12923,51 @@ elf32_arm_final_link_relocate (reloc_howto_type *	    howto,
       *unresolved_reloc_p = FALSE;
       return bfd_reloc_ok;
 
+    case R_ARM_THM_BF16:
+      {
+	bfd_vma relocation;
+	bfd_vma upper_insn = bfd_get_16 (input_bfd, hit_data);
+	bfd_vma lower_insn = bfd_get_16 (input_bfd, hit_data + 2);
+
+	if (globals->use_rel)
+	  {
+	    bfd_vma immA  = (upper_insn & 0x001f);
+	    bfd_vma immB  = (lower_insn & 0x07fe) >> 1;
+	    bfd_vma immC  = (lower_insn & 0x0800) >> 11;
+	    addend  = (immA << 12);
+	    addend |= (immB << 2);
+	    addend |= (immC << 1);
+	    addend |= 1;
+	    /* Sign extend.  */
+	    addend = (addend & 0x10000) ? addend - (1 << 17) : addend;
+	  }
+
+	value = get_value_helper (plt_offset, splt, input_section, sym_sec, h,
+				  info, input_bfd, rel, sym_name, st_type,
+				  globals, unresolved_reloc_p);
+
+	relocation  = value + addend;
+	relocation -= (input_section->output_section->vma
+		       + input_section->output_offset
+		       + rel->r_offset);
+
+	/* Put RELOCATION back into the insn.  */
+	{
+	  bfd_vma immA = (relocation & 0x0001f000) >> 12;
+	  bfd_vma immB = (relocation & 0x00000ffc) >> 2;
+	  bfd_vma immC = (relocation & 0x00000002) >> 1;
+
+	  upper_insn = (upper_insn & 0xffe0) | immA;
+	  lower_insn = (lower_insn & 0xf001) | (immC << 11) | (immB << 1);
+	}
+
+	/* Put the relocated value back in the object file:  */
+	bfd_put_16 (input_bfd, upper_insn, hit_data);
+	bfd_put_16 (input_bfd, lower_insn, hit_data + 2);
+
+	return bfd_reloc_ok;
+      }
+
     default:
       return bfd_reloc_notsupported;
     }
diff --git a/bfd/libbfd.h b/bfd/libbfd.h
index 02daa29b433e390507fe91e7a045f43eb85d548d..4a3fa144ad25b5a800501c352e6f0aa79509bb27 100644
--- a/bfd/libbfd.h
+++ b/bfd/libbfd.h
@@ -1530,6 +1530,7 @@ static const char *const bfd_reloc_code_real_names[] = { "@@uninitialized@@",
   "BFD_RELOC_ARM_PCREL_CALL",
   "BFD_RELOC_ARM_PCREL_JUMP",
   "BFD_RELOC_THUMB_PCREL_BRANCH5",
+  "BFD_RELOC_ARM_THUMB_BF17",
   "BFD_RELOC_THUMB_PCREL_BRANCH7",
   "BFD_RELOC_THUMB_PCREL_BRANCH9",
   "BFD_RELOC_THUMB_PCREL_BRANCH12",
diff --git a/bfd/reloc.c b/bfd/reloc.c
index a071dc75c0499192077da30aba8ee7fc3d62dacb..b351d120d1d1894ba64a3eb2d32e21884648fd6a 100644
--- a/bfd/reloc.c
+++ b/bfd/reloc.c
@@ -3019,6 +3019,11 @@ ENUM
 ENUMDOC
   ARM 5-bit pc-relative branch for Branch Future instructions.
 
+ENUM
+  BFD_RELOC_ARM_THUMB_BF17
+ENUMDOC
+  ARM 17-bit pc-relative branch for Branch Future instructions.
+
 ENUM
   BFD_RELOC_THUMB_PCREL_BRANCH7
 ENUMX
diff --git a/elfcpp/arm.h b/elfcpp/arm.h
index fb5cc25f0695fb62e398c6c9a26b7e2c59e40be0..b4cd67f87ce49288ee40adb7653443b493774267 100644
--- a/elfcpp/arm.h
+++ b/elfcpp/arm.h
@@ -194,7 +194,10 @@ enum
   R_ARM_ME_TOO = 128,		// Obsolete
   R_ARM_THM_TLS_DESCSEQ16 = 129,// Static	Thumb16
   R_ARM_THM_TLS_DESCSEQ32 = 130,// Static	Thumb32
-  // 131 - 139			Unallocated
+  // 131 - 135			Unallocated
+  // Relocations for Armv8.1-M Mainline (BF/BFL)
+  R_ARM_THM_BF16 = 136,		// Static       Thumb32 ((S + A) | T) – P
+  // 139			Unallocated
   // 140 - 159			Dynamic		Reserved for future allocation
   R_ARM_IRELATIVE = 160,	// Dynamic
   // 161 - 255			Unallocated
diff --git a/gas/config/tc-arm.c b/gas/config/tc-arm.c
index 14d114adbeec62b11fa3bc7d4f7cb3cdd030bf8f..d3a21d63575c194051606bb723a224d3c10334e9 100644
--- a/gas/config/tc-arm.c
+++ b/gas/config/tc-arm.c
@@ -22853,6 +22853,7 @@ md_pcrel_from_section (fixS * fixP, segT seg)
     case BFD_RELOC_THUMB_PCREL_BRANCH12:
     case BFD_RELOC_THUMB_PCREL_BRANCH20:
     case BFD_RELOC_THUMB_PCREL_BRANCH25:
+    case BFD_RELOC_ARM_THUMB_BF17:
       return base + 4;
 
     case BFD_RELOC_THUMB_PCREL_BRANCH23:
@@ -24750,6 +24751,39 @@ md_apply_fix (fixS *	fixP,
 	}
       break;
 
+    case BFD_RELOC_ARM_THUMB_BF17:
+      if (fixP->fx_addsy
+	  && (S_GET_SEGMENT (fixP->fx_addsy) == seg)
+	  && !S_FORCE_RELOC (fixP->fx_addsy, TRUE)
+	  && ARM_IS_FUNC (fixP->fx_addsy)
+	  && ARM_CPU_HAS_FEATURE (selected_cpu, arm_ext_v8_1m_main))
+	{
+	  /* Force a relocation for a branch 17 bits wide.  */
+	  fixP->fx_done = 0;
+	}
+
+      if (v8_1_branch_value_check (value, 17, TRUE) == FAIL)
+	as_bad_where (fixP->fx_file, fixP->fx_line,
+		      BAD_BRANCH_OFF);
+
+      if (fixP->fx_done || !seg->use_rela_p)
+	{
+	  offsetT newval2;
+	  addressT immA, immB, immC;
+
+	  immA = (value & 0x0001f000) >> 12;
+	  immB = (value & 0x00000ffc) >> 2;
+	  immC = (value & 0x00000002) >> 1;
+
+	  newval   = md_chars_to_number (buf, THUMB_SIZE);
+	  newval2  = md_chars_to_number (buf + THUMB_SIZE, THUMB_SIZE);
+	  newval  |= immA;
+	  newval2 |= (immC << 11) | (immB << 1);
+	  md_number_to_chars (buf, newval, THUMB_SIZE);
+	  md_number_to_chars (buf + THUMB_SIZE, newval2, THUMB_SIZE);
+	}
+      break;
+
     case BFD_RELOC_ARM_V4BX:
       /* This will need to go in the object file.  */
       fixP->fx_done = 0;
@@ -24932,6 +24966,7 @@ tc_gen_reloc (asection *section, fixS *fixp)
     case BFD_RELOC_ARM_GOTFUNCDESC:
     case BFD_RELOC_ARM_GOTOFFFUNCDESC:
     case BFD_RELOC_ARM_FUNCDESC:
+    case BFD_RELOC_ARM_THUMB_BF17:
       code = fixp->fx_r_type;
       break;
 
diff --git a/include/elf/arm.h b/include/elf/arm.h
index daf1d94391ea23c49cb646af430d2db8ef46c51e..2c6d4ef18a96e10fb206248df151c44a67757042 100644
--- a/include/elf/arm.h
+++ b/include/elf/arm.h
@@ -241,6 +241,7 @@ START_RELOC_NUMBERS (elf_arm_reloc_type)
   RELOC_NUMBER (R_ARM_THM_ALU_ABS_G1_NC,133)
   RELOC_NUMBER (R_ARM_THM_ALU_ABS_G2_NC,134)
   RELOC_NUMBER (R_ARM_THM_ALU_ABS_G3_NC,135)
+  RELOC_NUMBER (R_ARM_THM_BF16,		136)
 
   RELOC_NUMBER (R_ARM_IRELATIVE,      	160)
   RELOC_NUMBER (R_ARM_GOTFUNCDESC,    	161)
diff --git a/opcodes/arm-dis.c b/opcodes/arm-dis.c
index 0fe44877db243b8cbce50fed451e65fcacf9fabc..71443d3ea41966309d4516754eb8f2e38e3e6df0 100644
--- a/opcodes/arm-dis.c
+++ b/opcodes/arm-dis.c
@@ -2715,6 +2715,7 @@ static const struct opcode16 thumb_opcodes[] =
        %E		print the lsb and width fields of a bfc/bfi instruction
        %F		print the lsb and width fields of a sbfx/ubfx instruction
        %G		print a fallback offset for Branch Future instructions
+       %W		print an offset for BF instruction
        %b		print a conditional branch offset
        %B		print an unconditional branch offset
        %s		print the shift field of an SSAT instruction
@@ -5871,6 +5872,23 @@ print_insn_thumb32 (bfd_vma pc, struct disassemble_info *info, long given)
 		}
 		break;
 
+	      case 'W':
+		{
+		  unsigned int immA = (given & 0x001f0000u) >> 16;
+		  unsigned int immB = (given & 0x000007feu) >> 1;
+		  unsigned int immC = (given & 0x00000800u) >> 11;
+		  bfd_vma offset = 0;
+
+		  offset |= immA << 12;
+		  offset |= immB << 2;
+		  offset |= immC << 1;
+		  /* Sign extend.  */
+		  offset = (offset & 0x10000) ? offset - (1 << 17) : offset;
+
+		  info->print_address_func (pc + 4 + offset, info);
+		}
+		break;
+
 	      case 'b':
 		{
 		  unsigned int S = (given & 0x04000000u) >> 26;