[AArch64] Add SVE condition codes

SVE defines new names for existing NZCV conditions, to reflect the
result of instructions like PTEST.  This patch adds support for these
names.

The patch also adds comments to the disassembly output to show the
alternative names of a condition code.  For example:

	cinv	x0, x1, cc

becomes:

     	cinv	x0, x1, cc  // cc = lo, ul, last

and:

	b.cc	f0 <...>

becomes:

     	b.cc	f0 <...>  // b.lo, b.ul, b.last

Doing this for the SVE names follows the practice recommended by the
SVE specification and is definitely useful when reading SVE code.
If the feeling is that it's too distracting elsewhere, we could add
an option to turn it off.

include/
	* opcode/aarch64.h (aarch64_cond): Bump array size to 4.

opcodes/
	* aarch64-dis.c (remove_dot_suffix): New function, split out from...
	(print_mnemonic_name): ...here.
	(print_comment): New function.
	(print_aarch64_insn): Call it.
	* aarch64-opc.c (aarch64_conds): Add SVE names.
	(aarch64_print_operand): Print alternative condition names in
	a comment.

gas/
	* config/tc-aarch64.c (opcode_lookup): Search for the end of
	a condition name, rather than assuming that it will have exactly
	2 characters.
	(parse_operands): Likewise.
	* testsuite/gas/aarch64/alias.d: Add new condition-code comments
	to the expected output.
	* testsuite/gas/aarch64/beq_1.d: Likewise.
	* testsuite/gas/aarch64/float-fp16.d: Likewise.
	* testsuite/gas/aarch64/int-insns.d: Likewise.
	* testsuite/gas/aarch64/no-aliases.d: Likewise.
	* testsuite/gas/aarch64/programmer-friendly.d: Likewise.
	* testsuite/gas/aarch64/reloc-insn.d: Likewise.
	* testsuite/gas/aarch64/b_c_1.d, testsuite/gas/aarch64/b_c_1.s:
	New test.

ld/
	* testsuite/ld-aarch64/emit-relocs-280.d: Match branch comments.
	* testsuite/ld-aarch64/weak-undefined.d: Likewise.

3 files changed, 72 insertions, 20 deletions

diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index 1380def..cb610be 100644
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,5 +1,15 @@
 2016-09-21  Richard Sandiford  <richard.sandiford@arm.com>
 
+	* aarch64-dis.c (remove_dot_suffix): New function, split out from...
+	(print_mnemonic_name): ...here.
+	(print_comment): New function.
+	(print_aarch64_insn): Call it.
+	* aarch64-opc.c (aarch64_conds): Add SVE names.
+	(aarch64_print_operand): Print alternative condition names in
+	a comment.
+
+2016-09-21  Richard Sandiford  <richard.sandiford@arm.com>
+
 	* aarch64-tbl.h (OP_SVE_B, OP_SVE_BB, OP_SVE_BBBU, OP_SVE_BMB)
 	(OP_SVE_BPB, OP_SVE_BUB, OP_SVE_BUBB, OP_SVE_BUU, OP_SVE_BZ)
 	(OP_SVE_BZB, OP_SVE_BZBB, OP_SVE_BZU, OP_SVE_DD, OP_SVE_DDD)
diff --git a/opcodes/aarch64-dis.c b/opcodes/aarch64-dis.c
index 673d6e5..82afe8b 100644
--- a/opcodes/aarch64-dis.c
+++ b/opcodes/aarch64-dis.c
@@ -2787,6 +2787,22 @@ print_operands (bfd_vma pc, const aarch64_opcode *opcode,
     }
 }
 
+/* Set NAME to a copy of INST's mnemonic with the "." suffix removed.  */
+
+static void
+remove_dot_suffix (char *name, const aarch64_inst *inst)
+{
+  char *ptr;
+  size_t len;
+
+  ptr = strchr (inst->opcode->name, '.');
+  assert (ptr && inst->cond);
+  len = ptr - inst->opcode->name;
+  assert (len < 8);
+  strncpy (name, inst->opcode->name, len);
+  name[len] = '\0';
+}
+
 /* Print the instruction mnemonic name.  */
 
 static void
@@ -2797,21 +2813,35 @@ print_mnemonic_name (const aarch64_inst *inst, struct disassemble_info *info)
       /* For instructions that are truly conditionally executed, e.g. b.cond,
 	 prepare the full mnemonic name with the corresponding condition
 	 suffix.  */
-      char name[8], *ptr;
-      size_t len;
-
-      ptr = strchr (inst->opcode->name, '.');
-      assert (ptr && inst->cond);
-      len = ptr - inst->opcode->name;
-      assert (len < 8);
-      strncpy (name, inst->opcode->name, len);
-      name [len] = '\0';
+      char name[8];
+
+      remove_dot_suffix (name, inst);
       (*info->fprintf_func) (info->stream, "%s.%s", name, inst->cond->names[0]);
     }
   else
     (*info->fprintf_func) (info->stream, "%s", inst->opcode->name);
 }
 
+/* Decide whether we need to print a comment after the operands of
+   instruction INST.  */
+
+static void
+print_comment (const aarch64_inst *inst, struct disassemble_info *info)
+{
+  if (inst->opcode->flags & F_COND)
+    {
+      char name[8];
+      unsigned int i, num_conds;
+
+      remove_dot_suffix (name, inst);
+      num_conds = ARRAY_SIZE (inst->cond->names);
+      for (i = 1; i < num_conds && inst->cond->names[i]; ++i)
+	(*info->fprintf_func) (info->stream, "%s %s.%s",
+			       i == 1 ? "  //" : ",",
+			       name, inst->cond->names[i]);
+    }
+}
+
 /* Print the instruction according to *INST.  */
 
 static void
@@ -2820,6 +2850,7 @@ print_aarch64_insn (bfd_vma pc, const aarch64_inst *inst,
 {
   print_mnemonic_name (inst, info);
   print_operands (pc, inst->opcode, inst->operands, info);
+  print_comment (inst, info);
 }
 
 /* Entry-point of the instruction disassembler and printer.  */
diff --git a/opcodes/aarch64-opc.c b/opcodes/aarch64-opc.c
index d22e419..b07429d 100644
--- a/opcodes/aarch64-opc.c
+++ b/opcodes/aarch64-opc.c
@@ -334,18 +334,18 @@ aarch64_get_operand_desc (enum aarch64_opnd type)
 /* Table of all conditional affixes.  */
 const aarch64_cond aarch64_conds[16] =
 {
-  {{"eq"}, 0x0},
-  {{"ne"}, 0x1},
-  {{"cs", "hs"}, 0x2},
-  {{"cc", "lo", "ul"}, 0x3},
-  {{"mi"}, 0x4},
-  {{"pl"}, 0x5},
+  {{"eq", "none"}, 0x0},
+  {{"ne", "any"}, 0x1},
+  {{"cs", "hs", "nlast"}, 0x2},
+  {{"cc", "lo", "ul", "last"}, 0x3},
+  {{"mi", "first"}, 0x4},
+  {{"pl", "nfrst"}, 0x5},
   {{"vs"}, 0x6},
   {{"vc"}, 0x7},
-  {{"hi"}, 0x8},
-  {{"ls"}, 0x9},
-  {{"ge"}, 0xa},
-  {{"lt"}, 0xb},
+  {{"hi", "pmore"}, 0x8},
+  {{"ls", "plast"}, 0x9},
+  {{"ge", "tcont"}, 0xa},
+  {{"lt", "tstop"}, 0xb},
   {{"gt"}, 0xc},
   {{"le"}, 0xd},
   {{"al"}, 0xe},
@@ -2940,7 +2940,7 @@ aarch64_print_operand (char *buf, size_t size, bfd_vma pc,
 		       const aarch64_opnd_info *opnds, int idx, int *pcrel_p,
 		       bfd_vma *address)
 {
-  int i;
+  unsigned int i, num_conds;
   const char *name = NULL;
   const aarch64_opnd_info *opnd = opnds + idx;
   enum aarch64_modifier_kind kind;
@@ -3306,6 +3306,17 @@ aarch64_print_operand (char *buf, size_t size, bfd_vma pc,
     case AARCH64_OPND_COND:
     case AARCH64_OPND_COND1:
       snprintf (buf, size, "%s", opnd->cond->names[0]);
+      num_conds = ARRAY_SIZE (opnd->cond->names);
+      for (i = 1; i < num_conds && opnd->cond->names[i]; ++i)
+	{
+	  size_t len = strlen (buf);
+	  if (i == 1)
+	    snprintf (buf + len, size - len, "  // %s = %s",
+		      opnd->cond->names[0], opnd->cond->names[i]);
+	  else
+	    snprintf (buf + len, size - len, ", %s",
+		      opnd->cond->names[i]);
+	}
       break;
 
     case AARCH64_OPND_ADDR_ADRP: