[AArch64][SVE 20/32] Add support for tied operands

SVE has some instructions in which the same register appears twice
in the assembly string, once as an input and once as an output.
This patch adds a general mechanism for that.

The patch needs to add new information to the instruction entries.
One option would have been to extend the flags field of the opcode
to 64 bits (since we already rely on 64-bit integers being available
on the host).  However, the *_INSN macros mean that it's easy to add
new information as top-level fields without affecting the existing
table entries too much.  Going for that option seemed to give slightly
neater code.

include/
	* opcode/aarch64.h (aarch64_opcode): Add a tied_operand field.
	(AARCH64_OPDE_UNTIED_OPERAND): New aarch64_operand_error_kind.

opcodes/
	* aarch64-tbl.h (CORE_INSN, __FP_INSN, SIMD_INSN, CRYP_INSN)
	(_CRC_INSN, _LSE_INSN, _LOR_INSN, RDMA_INSN, FP16_INSN, SF16_INSN)
	(V8_2_INSN, aarch64_opcode_table): Initialize tied_operand field.
	* aarch64-opc.c (aarch64_match_operands_constraint): Check for
	tied operands.

gas/
	* config/tc-aarch64.c (output_operand_error_record): Handle
	AARCH64_OPDE_UNTIED_OPERAND.

7 files changed, 65 insertions, 16 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index ac9d359cd7d..425c37a7dde 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,5 +1,10 @@
 2016-09-21  Richard Sandiford  <richard.sandiford@arm.com>
 
+	* config/tc-aarch64.c (output_operand_error_record): Handle
+	AARCH64_OPDE_UNTIED_OPERAND.
+
+2016-09-21  Richard Sandiford  <richard.sandiford@arm.com>
+
 	* config/tc-aarch64.c (find_best_match): Simplify, allowing an
 	instruction with all-NIL qualifiers to fail to match.
 
diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index f50de702c9c..83352303cf0 100644
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -4371,6 +4371,11 @@ output_operand_error_record (const operand_error_record *record, char *str)
 	}
       break;
 
+    case AARCH64_OPDE_UNTIED_OPERAND:
+      as_bad (_("operand %d must be the same register as operand 1 -- `%s'"),
+	      detail->index + 1, str);
+      break;
+
     case AARCH64_OPDE_OUT_OF_RANGE:
       if (detail->data[0] != detail->data[1])
 	as_bad (_("%s out of range %d to %d at operand %d -- `%s'"),
diff --git a/include/ChangeLog b/include/ChangeLog
index 21ddbfdd824..e6c3dbdf508 100644
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,5 +1,10 @@
 2016-09-21  Richard Sandiford  <richard.sandiford@arm.com>
 
+	* opcode/aarch64.h (aarch64_opcode): Add a tied_operand field.
+	(AARCH64_OPDE_UNTIED_OPERAND): New aarch64_operand_error_kind.
+
+2016-09-21  Richard Sandiford  <richard.sandiford@arm.com>
+
 	* opcode/aarch64.h (F_STRICT): New flag.
 
 2016-09-07  Richard Earnshaw  <rearnsha@arm.com>
diff --git a/include/opcode/aarch64.h b/include/opcode/aarch64.h
index 24a2ddbdc05..d39f10d0cfc 100644
--- a/include/opcode/aarch64.h
+++ b/include/opcode/aarch64.h
@@ -539,6 +539,10 @@ struct aarch64_opcode
   /* Flags providing information about this instruction */
   uint32_t flags;
 
+  /* If nonzero, this operand and operand 0 are both registers and
+     are required to have the same register number.  */
+  unsigned char tied_operand;
+
   /* If non-NULL, a function to verify that a given instruction is valid.  */
   bfd_boolean (* verifier) (const struct aarch64_opcode *, const aarch64_insn);
 };
@@ -872,6 +876,10 @@ typedef struct aarch64_inst aarch64_inst;
      No syntax error, but the operands are not a valid combination, e.g.
      FMOV D0,S0
 
+   AARCH64_OPDE_UNTIED_OPERAND
+     The asm failed to use the same register for a destination operand
+     and a tied source operand.
+
    AARCH64_OPDE_OUT_OF_RANGE
      Error about some immediate value out of a valid range.
 
@@ -908,6 +916,7 @@ enum aarch64_operand_error_kind
   AARCH64_OPDE_SYNTAX_ERROR,
   AARCH64_OPDE_FATAL_SYNTAX_ERROR,
   AARCH64_OPDE_INVALID_VARIANT,
+  AARCH64_OPDE_UNTIED_OPERAND,
   AARCH64_OPDE_OUT_OF_RANGE,
   AARCH64_OPDE_UNALIGNED,
   AARCH64_OPDE_REG_LIST,
diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index eab68113b48..925ea1eb101 100644
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,5 +1,13 @@
 2016-09-21  Richard Sandiford  <richard.sandiford@arm.com>
 
+	* aarch64-tbl.h (CORE_INSN, __FP_INSN, SIMD_INSN, CRYP_INSN)
+	(_CRC_INSN, _LSE_INSN, _LOR_INSN, RDMA_INSN, FP16_INSN, SF16_INSN)
+	(V8_2_INSN, aarch64_opcode_table): Initialize tied_operand field.
+	* aarch64-opc.c (aarch64_match_operands_constraint): Check for
+	tied operands.
+
+2016-09-21  Richard Sandiford  <richard.sandiford@arm.com>
+
 	* aarch64-opc.c (get_offset_int_reg_name): New function.
 	(print_immediate_offset_address): Likewise.
 	(print_register_offset_address): Take the base and offset
diff --git a/opcodes/aarch64-opc.c b/opcodes/aarch64-opc.c
index 7a73c7e409f..30501fcc47e 100644
--- a/opcodes/aarch64-opc.c
+++ b/opcodes/aarch64-opc.c
@@ -2058,6 +2058,23 @@ aarch64_match_operands_constraint (aarch64_inst *inst,
 
   DEBUG_TRACE ("enter");
 
+  /* Check for cases where a source register needs to be the same as the
+     destination register.  Do this before matching qualifiers since if
+     an instruction has both invalid tying and invalid qualifiers,
+     the error about qualifiers would suggest several alternative
+     instructions that also have invalid tying.  */
+  i = inst->opcode->tied_operand;
+  if (i > 0 && (inst->operands[0].reg.regno != inst->operands[i].reg.regno))
+    {
+      if (mismatch_detail)
+	{
+	  mismatch_detail->kind = AARCH64_OPDE_UNTIED_OPERAND;
+	  mismatch_detail->index = i;
+	  mismatch_detail->error = NULL;
+	}
+      return 0;
+    }
+
   /* Match operands' qualifier.
      *INST has already had qualifier establish for some, if not all, of
      its operands; we need to find out whether these established
diff --git a/opcodes/aarch64-tbl.h b/opcodes/aarch64-tbl.h
index 9a831e4ffe1..8f1c9b237d9 100644
--- a/opcodes/aarch64-tbl.h
+++ b/opcodes/aarch64-tbl.h
@@ -1393,27 +1393,27 @@ static const aarch64_feature_set aarch64_feature_stat_profile =
 #define ARMV8_2		&aarch64_feature_v8_2
 
 #define CORE_INSN(NAME,OPCODE,MASK,CLASS,OP,OPS,QUALS,FLAGS) \
-  { NAME, OPCODE, MASK, CLASS, OP, CORE, OPS, QUALS, FLAGS, NULL }
+  { NAME, OPCODE, MASK, CLASS, OP, CORE, OPS, QUALS, FLAGS, 0, NULL }
 #define __FP_INSN(NAME,OPCODE,MASK,CLASS,OP,OPS,QUALS,FLAGS) \
-  { NAME, OPCODE, MASK, CLASS, OP, FP, OPS, QUALS, FLAGS, NULL }
+  { NAME, OPCODE, MASK, CLASS, OP, FP, OPS, QUALS, FLAGS, 0, NULL }
 #define SIMD_INSN(NAME,OPCODE,MASK,CLASS,OP,OPS,QUALS,FLAGS) \
-  { NAME, OPCODE, MASK, CLASS, OP, SIMD, OPS, QUALS, FLAGS, NULL }
+  { NAME, OPCODE, MASK, CLASS, OP, SIMD, OPS, QUALS, FLAGS, 0, NULL }
 #define CRYP_INSN(NAME,OPCODE,MASK,CLASS,OPS,QUALS,FLAGS) \
-  { NAME, OPCODE, MASK, CLASS, 0, CRYPTO, OPS, QUALS, FLAGS, NULL }
+  { NAME, OPCODE, MASK, CLASS, 0, CRYPTO, OPS, QUALS, FLAGS, 0, NULL }
 #define _CRC_INSN(NAME,OPCODE,MASK,CLASS,OPS,QUALS,FLAGS) \
-  { NAME, OPCODE, MASK, CLASS, 0, CRC, OPS, QUALS, FLAGS, NULL }
+  { NAME, OPCODE, MASK, CLASS, 0, CRC, OPS, QUALS, FLAGS, 0, NULL }
 #define _LSE_INSN(NAME,OPCODE,MASK,CLASS,OPS,QUALS,FLAGS) \
-  { NAME, OPCODE, MASK, CLASS, 0, LSE, OPS, QUALS, FLAGS, NULL }
+  { NAME, OPCODE, MASK, CLASS, 0, LSE, OPS, QUALS, FLAGS, 0, NULL }
 #define _LOR_INSN(NAME,OPCODE,MASK,CLASS,OPS,QUALS,FLAGS) \
-  { NAME, OPCODE, MASK, CLASS, 0, LOR, OPS, QUALS, FLAGS, NULL }
+  { NAME, OPCODE, MASK, CLASS, 0, LOR, OPS, QUALS, FLAGS, 0, NULL }
 #define RDMA_INSN(NAME,OPCODE,MASK,CLASS,OPS,QUALS,FLAGS) \
-  { NAME, OPCODE, MASK, CLASS, 0, RDMA, OPS, QUALS, FLAGS, NULL }
+  { NAME, OPCODE, MASK, CLASS, 0, RDMA, OPS, QUALS, FLAGS, 0, NULL }
 #define FF16_INSN(NAME,OPCODE,MASK,CLASS,OPS,QUALS,FLAGS) \
-  { NAME, OPCODE, MASK, CLASS, 0, FP_F16, OPS, QUALS, FLAGS, NULL }
+  { NAME, OPCODE, MASK, CLASS, 0, FP_F16, OPS, QUALS, FLAGS, 0, NULL }
 #define SF16_INSN(NAME,OPCODE,MASK,CLASS,OPS,QUALS,FLAGS)		\
-  { NAME, OPCODE, MASK, CLASS, 0, SIMD_F16, OPS, QUALS, FLAGS, NULL }
+  { NAME, OPCODE, MASK, CLASS, 0, SIMD_F16, OPS, QUALS, FLAGS, 0, NULL }
 #define V8_2_INSN(NAME,OPCODE,MASK,CLASS,OP,OPS,QUALS,FLAGS) \
-  { NAME, OPCODE, MASK, CLASS, OP, ARMV8_2, OPS, QUALS, FLAGS, NULL }
+  { NAME, OPCODE, MASK, CLASS, OP, ARMV8_2, OPS, QUALS, FLAGS, 0, NULL }
 
 struct aarch64_opcode aarch64_opcode_table[] =
 {
@@ -2389,13 +2389,13 @@ struct aarch64_opcode aarch64_opcode_table[] =
   CORE_INSN ("ldp", 0x29400000, 0x7ec00000, ldstpair_off, 0, OP3 (Rt, Rt2, ADDR_SIMM7), QL_LDST_PAIR_R, F_SF),
   CORE_INSN ("stp", 0x2d000000, 0x3fc00000, ldstpair_off, 0, OP3 (Ft, Ft2, ADDR_SIMM7), QL_LDST_PAIR_FP, 0),
   CORE_INSN ("ldp", 0x2d400000, 0x3fc00000, ldstpair_off, 0, OP3 (Ft, Ft2, ADDR_SIMM7), QL_LDST_PAIR_FP, 0),
-  {"ldpsw", 0x69400000, 0xffc00000, ldstpair_off, 0, CORE, OP3 (Rt, Rt2, ADDR_SIMM7), QL_LDST_PAIR_X32, 0, VERIFIER (ldpsw)},
+  {"ldpsw", 0x69400000, 0xffc00000, ldstpair_off, 0, CORE, OP3 (Rt, Rt2, ADDR_SIMM7), QL_LDST_PAIR_X32, 0, 0, VERIFIER (ldpsw)},
   /* Load/store register pair (indexed).  */
   CORE_INSN ("stp", 0x28800000, 0x7ec00000, ldstpair_indexed, 0, OP3 (Rt, Rt2, ADDR_SIMM7), QL_LDST_PAIR_R, F_SF),
   CORE_INSN ("ldp", 0x28c00000, 0x7ec00000, ldstpair_indexed, 0, OP3 (Rt, Rt2, ADDR_SIMM7), QL_LDST_PAIR_R, F_SF),
   CORE_INSN ("stp", 0x2c800000, 0x3ec00000, ldstpair_indexed, 0, OP3 (Ft, Ft2, ADDR_SIMM7), QL_LDST_PAIR_FP, 0),
   CORE_INSN ("ldp", 0x2cc00000, 0x3ec00000, ldstpair_indexed, 0, OP3 (Ft, Ft2, ADDR_SIMM7), QL_LDST_PAIR_FP, 0),
-  {"ldpsw", 0x68c00000, 0xfec00000, ldstpair_indexed, 0, CORE, OP3 (Rt, Rt2, ADDR_SIMM7), QL_LDST_PAIR_X32, 0, VERIFIER (ldpsw)},
+  {"ldpsw", 0x68c00000, 0xfec00000, ldstpair_indexed, 0, CORE, OP3 (Rt, Rt2, ADDR_SIMM7), QL_LDST_PAIR_X32, 0, 0, VERIFIER (ldpsw)},
   /* Load register (literal).  */
   CORE_INSN ("ldr",   0x18000000, 0xbf000000, loadlit, OP_LDR_LIT,   OP2 (Rt, ADDR_PCREL19),    QL_R_PCREL, F_GPRSIZE_IN_Q),
   CORE_INSN ("ldr",   0x1c000000, 0x3f000000, loadlit, OP_LDRV_LIT,  OP2 (Ft, ADDR_PCREL19),    QL_FP_PCREL, 0),
@@ -2613,8 +2613,8 @@ struct aarch64_opcode aarch64_opcode_table[] =
   CORE_INSN ("wfi", 0xd503207f, 0xffffffff, ic_system, 0, OP0 (), {}, F_ALIAS),
   CORE_INSN ("sev", 0xd503209f, 0xffffffff, ic_system, 0, OP0 (), {}, F_ALIAS),
   CORE_INSN ("sevl",0xd50320bf, 0xffffffff, ic_system, 0, OP0 (), {}, F_ALIAS),
-  {"esb", 0xd503221f, 0xffffffff, ic_system, 0, RAS, OP0 (), {}, F_ALIAS, NULL},
-  {"psb", 0xd503223f, 0xffffffff, ic_system, 0, STAT_PROFILE, OP1 (BARRIER_PSB), {}, F_ALIAS, NULL},
+  {"esb", 0xd503221f, 0xffffffff, ic_system, 0, RAS, OP0 (), {}, F_ALIAS, 0, NULL},
+  {"psb", 0xd503223f, 0xffffffff, ic_system, 0, STAT_PROFILE, OP1 (BARRIER_PSB), {}, F_ALIAS, 0, NULL},
   CORE_INSN ("clrex", 0xd503305f, 0xfffff0ff, ic_system, 0, OP1 (UIMM4), {}, F_OPD0_OPT | F_DEFAULT (0xF)),
   CORE_INSN ("dsb", 0xd503309f, 0xfffff0ff, ic_system, 0, OP1 (BARRIER), {}, 0),
   CORE_INSN ("dmb", 0xd50330bf, 0xfffff0ff, ic_system, 0, OP1 (BARRIER), {}, 0),
@@ -2648,7 +2648,7 @@ struct aarch64_opcode aarch64_opcode_table[] =
   CORE_INSN ("bgt", 0x5400000c, 0xff00001f, condbranch, 0, OP1 (ADDR_PCREL19), QL_PCREL_NIL, F_ALIAS | F_PSEUDO),
   CORE_INSN ("ble", 0x5400000d, 0xff00001f, condbranch, 0, OP1 (ADDR_PCREL19), QL_PCREL_NIL, F_ALIAS | F_PSEUDO),
 
-  {0, 0, 0, 0, 0, 0, {}, {}, 0, NULL},
+  {0, 0, 0, 0, 0, 0, {}, {}, 0, 0, NULL},
 };
 
 #ifdef AARCH64_OPERANDS