Modify AArch64 Assembly and disassembly functions to be able to fail and report why.

This patch if the first patch in a series to add the ability to add constraints
to system registers that an instruction must adhere to in order for the register
to be usable with that instruction.

These constraints can also be used to disambiguate between registers with the
same encoding during disassembly.

This patch adds a new flags entry in the sysreg structures and ensures it is
filled in and read out during assembly/disassembly. It also adds the ability for
the assemble and disassemble functions to be able to gracefully fail and re-use
the existing error reporting infrastructure.

The return type of these functions are changed to a boolean to denote success or
failure and the error structure is passed around to them. This requires
aarch64-gen changes so a lot of the changes here are just mechanical.

gas/

	PR binutils/21446
	* config/tc-aarch64.c (parse_sys_reg): Return register flags.
	(parse_operands): Fill in register flags.

gdb/

	PR binutils/21446
	* aarch64-tdep.c (aarch64_analyze_prologue,
	aarch64_software_single_step, aarch64_displaced_step_copy_insn):
	Indicate not interested in errors.

include/

	PR binutils/21446
	* opcode/aarch64.h (aarch64_opnd_info): Change sysreg to struct.
	(aarch64_decode_insn): Accept error struct.

opcodes/

	PR binutils/21446
	* aarch64-asm.h (aarch64_insert_operand, aarch64_##x): Return boolean
	and take error struct.
	* aarch64-asm.c (aarch64_ext_regno, aarch64_ins_reglane,
	aarch64_ins_reglist, aarch64_ins_ldst_reglist,
	aarch64_ins_ldst_reglist_r, aarch64_ins_ldst_elemlist,
	aarch64_ins_advsimd_imm_shift, aarch64_ins_imm, aarch64_ins_imm_half,
	aarch64_ins_advsimd_imm_modified, aarch64_ins_fpimm,
	aarch64_ins_imm_rotate1, aarch64_ins_imm_rotate2, aarch64_ins_fbits,
	aarch64_ins_aimm, aarch64_ins_limm_1, aarch64_ins_limm,
	aarch64_ins_inv_limm, aarch64_ins_ft, aarch64_ins_addr_simple,
	aarch64_ins_addr_regoff, aarch64_ins_addr_offset, aarch64_ins_addr_simm,
	aarch64_ins_addr_simm10, aarch64_ins_addr_uimm12,
	aarch64_ins_simd_addr_post, aarch64_ins_cond, aarch64_ins_sysreg,
	aarch64_ins_pstatefield, aarch64_ins_sysins_op, aarch64_ins_barrier,
	aarch64_ins_prfop, aarch64_ins_hint, aarch64_ins_reg_extended,
	aarch64_ins_reg_shifted, aarch64_ins_sve_addr_ri_s4xvl,
	aarch64_ins_sve_addr_ri_s6xvl, aarch64_ins_sve_addr_ri_s9xvl,
	aarch64_ins_sve_addr_ri_s4, aarch64_ins_sve_addr_ri_u6,
	aarch64_ins_sve_addr_rr_lsl, aarch64_ins_sve_addr_rz_xtw,
	aarch64_ins_sve_addr_zi_u5, aarch64_ext_sve_addr_zz,
	aarch64_ins_sve_addr_zz_lsl, aarch64_ins_sve_addr_zz_sxtw,
	aarch64_ins_sve_addr_zz_uxtw, aarch64_ins_sve_aimm,
	aarch64_ins_sve_asimm, aarch64_ins_sve_index, aarch64_ins_sve_limm_mov,
	aarch64_ins_sve_quad_index, aarch64_ins_sve_reglist,
	aarch64_ins_sve_scale, aarch64_ins_sve_shlimm, aarch64_ins_sve_shrimm,
	aarch64_ins_sve_float_half_one, aarch64_ins_sve_float_half_two,
	aarch64_ins_sve_float_zero_one, aarch64_opcode_encode): Likewise.
	* aarch64-dis.h (aarch64_extract_operand, aarch64_##x): Likewise.
	* aarch64-dis.c (aarch64_ext_regno, aarch64_ext_reglane,
	aarch64_ext_reglist, aarch64_ext_ldst_reglist,
	aarch64_ext_ldst_reglist_r, aarch64_ext_ldst_elemlist,
	aarch64_ext_advsimd_imm_shift, aarch64_ext_imm, aarch64_ext_imm_half,
	aarch64_ext_advsimd_imm_modified, aarch64_ext_fpimm,
	aarch64_ext_imm_rotate1, aarch64_ext_imm_rotate2, aarch64_ext_fbits,
	aarch64_ext_aimm, aarch64_ext_limm_1, aarch64_ext_limm, decode_limm,
	aarch64_ext_inv_limm, aarch64_ext_ft, aarch64_ext_addr_simple,
	aarch64_ext_addr_regoff, aarch64_ext_addr_offset, aarch64_ext_addr_simm,
	aarch64_ext_addr_simm10, aarch64_ext_addr_uimm12,
	aarch64_ext_simd_addr_post, aarch64_ext_cond, aarch64_ext_sysreg,
	aarch64_ext_pstatefield, aarch64_ext_sysins_op, aarch64_ext_barrier,
	aarch64_ext_prfop, aarch64_ext_hint, aarch64_ext_reg_extended,
	aarch64_ext_reg_shifted, aarch64_ext_sve_addr_ri_s4xvl,
	aarch64_ext_sve_addr_ri_s6xvl, aarch64_ext_sve_addr_ri_s9xvl,
	aarch64_ext_sve_addr_ri_s4, aarch64_ext_sve_addr_ri_u6,
	aarch64_ext_sve_addr_rr_lsl, aarch64_ext_sve_addr_rz_xtw,
	aarch64_ext_sve_addr_zi_u5, aarch64_ext_sve_addr_zz,
	aarch64_ext_sve_addr_zz_lsl, aarch64_ext_sve_addr_zz_sxtw,
	aarch64_ext_sve_addr_zz_uxtw, aarch64_ext_sve_aimm,
	aarch64_ext_sve_asimm, aarch64_ext_sve_index, aarch64_ext_sve_limm_mov,
	aarch64_ext_sve_quad_index, aarch64_ext_sve_reglist,
	aarch64_ext_sve_scale, aarch64_ext_sve_shlimm, aarch64_ext_sve_shrimm,
	aarch64_ext_sve_float_half_one, aarch64_ext_sve_float_half_two,
	aarch64_ext_sve_float_zero_one, aarch64_opcode_decode): Likewise.
	(determine_disassembling_preference, aarch64_decode_insn,
	print_insn_aarch64_word, print_insn_data): Take errors struct.
	(print_insn_aarch64): Use errors.
	* aarch64-asm-2.c: Regenerate.
	* aarch64-dis-2.c: Regenerate.
	* aarch64-gen.c (print_operand_inserter): Use errors and change type to
	boolean in aarch64_insert_operan.
	(print_operand_extractor): Likewise.
	* aarch64-opc.c (aarch64_print_operand): Use sysreg struct.

1 files changed, 248 insertions, 186 deletions

diff --git a/opcodes/aarch64-asm.c b/opcodes/aarch64-asm.c
index a4c6a27..67c9b6e 100644
--- a/opcodes/aarch64-asm.c
+++ b/opcodes/aarch64-asm.c
@@ -78,21 +78,23 @@ insert_all_fields (const aarch64_operand *self, aarch64_insn *code,
 /* Operand inserters.  */
 
 /* Insert register number.  */
-const char *
+bfd_boolean
 aarch64_ins_regno (const aarch64_operand *self, const aarch64_opnd_info *info,
 		   aarch64_insn *code,
-		   const aarch64_inst *inst ATTRIBUTE_UNUSED)
+		   const aarch64_inst *inst ATTRIBUTE_UNUSED,
+		   aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   insert_field (self->fields[0], code, info->reg.regno, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Insert register number, index and/or other data for SIMD register element
    operand, e.g. the last source operand in
      SQDMLAL <Va><d>, <Vb><n>, <Vm>.<Ts>[<index>].  */
-const char *
+bfd_boolean
 aarch64_ins_reglane (const aarch64_operand *self, const aarch64_opnd_info *info,
-		     aarch64_insn *code, const aarch64_inst *inst)
+		     aarch64_insn *code, const aarch64_inst *inst,
+		     aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   /* regno */
   insert_field (self->fields[0], code, info->reglane.regno, inst->opcode->mask);
@@ -173,28 +175,30 @@ aarch64_ins_reglane (const aarch64_operand *self, const aarch64_opnd_info *info,
 	  assert (0);
 	}
     }
-  return NULL;
+  return TRUE;
 }
 
 /* Insert regno and len field of a register list operand, e.g. Vn in TBL.  */
-const char *
+bfd_boolean
 aarch64_ins_reglist (const aarch64_operand *self, const aarch64_opnd_info *info,
 		     aarch64_insn *code,
-		     const aarch64_inst *inst ATTRIBUTE_UNUSED)
+		     const aarch64_inst *inst ATTRIBUTE_UNUSED,
+		     aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   /* R */
   insert_field (self->fields[0], code, info->reglist.first_regno, 0);
   /* len */
   insert_field (FLD_len, code, info->reglist.num_regs - 1, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Insert Rt and opcode fields for a register list operand, e.g. Vt
    in AdvSIMD load/store instructions.  */
-const char *
+bfd_boolean
 aarch64_ins_ldst_reglist (const aarch64_operand *self ATTRIBUTE_UNUSED,
 			  const aarch64_opnd_info *info, aarch64_insn *code,
-			  const aarch64_inst *inst)
+			  const aarch64_inst *inst,
+			  aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   aarch64_insn value = 0;
   /* Number of elements in each structure to be loaded/stored.  */
@@ -229,15 +233,16 @@ aarch64_ins_ldst_reglist (const aarch64_operand *self ATTRIBUTE_UNUSED,
     }
   insert_field (FLD_opcode, code, value, 0);
 
-  return NULL;
+  return TRUE;
 }
 
 /* Insert Rt and S fields for a register list operand, e.g. Vt in AdvSIMD load
    single structure to all lanes instructions.  */
-const char *
+bfd_boolean
 aarch64_ins_ldst_reglist_r (const aarch64_operand *self ATTRIBUTE_UNUSED,
 			    const aarch64_opnd_info *info, aarch64_insn *code,
-			    const aarch64_inst *inst)
+			    const aarch64_inst *inst,
+			    aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   aarch64_insn value;
   /* The opcode dependent area stores the number of elements in
@@ -254,15 +259,16 @@ aarch64_ins_ldst_reglist_r (const aarch64_operand *self ATTRIBUTE_UNUSED,
     value = (aarch64_insn) 1;
   insert_field (FLD_S, code, value, 0);
 
-  return NULL;
+  return TRUE;
 }
 
 /* Insert Q, opcode<2:1>, S, size and Rt fields for a register element list
    operand e.g. Vt in AdvSIMD load/store single element instructions.  */
-const char *
+bfd_boolean
 aarch64_ins_ldst_elemlist (const aarch64_operand *self ATTRIBUTE_UNUSED,
 			   const aarch64_opnd_info *info, aarch64_insn *code,
-			   const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			   const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			   aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   aarch64_field field = {0, 0};
   aarch64_insn QSsize = 0;	/* fields Q:S:size.  */
@@ -302,16 +308,17 @@ aarch64_ins_ldst_elemlist (const aarch64_operand *self ATTRIBUTE_UNUSED,
   gen_sub_field (FLD_asisdlso_opcode, 1, 2, &field);
   insert_field_2 (&field, code, opcodeh2, 0);
 
-  return NULL;
+  return TRUE;
 }
 
 /* Insert fields immh:immb and/or Q for e.g. the shift immediate in
    SSHR <Vd>.<T>, <Vn>.<T>, #<shift>
    or SSHR <V><d>, <V><n>, #<shift>.  */
-const char *
+bfd_boolean
 aarch64_ins_advsimd_imm_shift (const aarch64_operand *self ATTRIBUTE_UNUSED,
 			       const aarch64_opnd_info *info,
-			       aarch64_insn *code, const aarch64_inst *inst)
+			       aarch64_insn *code, const aarch64_inst *inst,
+			       aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   unsigned val = aarch64_get_qualifier_standard_value (info->qualifier);
   aarch64_insn Q, imm;
@@ -357,15 +364,16 @@ aarch64_ins_advsimd_imm_shift (const aarch64_operand *self ATTRIBUTE_UNUSED,
     imm = info->imm.value + (8 << (unsigned)val);
   insert_fields (code, imm, 0, 2, FLD_immb, FLD_immh);
 
-  return NULL;
+  return TRUE;
 }
 
 /* Insert fields for e.g. the immediate operands in
    BFM <Wd>, <Wn>, #<immr>, #<imms>.  */
-const char *
+bfd_boolean
 aarch64_ins_imm (const aarch64_operand *self, const aarch64_opnd_info *info,
 		 aarch64_insn *code,
-		 const aarch64_inst *inst ATTRIBUTE_UNUSED)
+		 const aarch64_inst *inst ATTRIBUTE_UNUSED,
+		 aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   int64_t imm;
 
@@ -373,29 +381,32 @@ aarch64_ins_imm (const aarch64_operand *self, const aarch64_opnd_info *info,
   if (operand_need_shift_by_two (self))
     imm >>= 2;
   insert_all_fields (self, code, imm);
-  return NULL;
+  return TRUE;
 }
 
 /* Insert immediate and its shift amount for e.g. the last operand in
      MOVZ <Wd>, #<imm16>{, LSL #<shift>}.  */
-const char *
+bfd_boolean
 aarch64_ins_imm_half (const aarch64_operand *self, const aarch64_opnd_info *info,
-		      aarch64_insn *code, const aarch64_inst *inst)
+		      aarch64_insn *code, const aarch64_inst *inst,
+		      aarch64_operand_error *errors)
 {
   /* imm16 */
-  aarch64_ins_imm (self, info, code, inst);
+  aarch64_ins_imm (self, info, code, inst, errors);
   /* hw */
   insert_field (FLD_hw, code, info->shifter.amount >> 4, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Insert cmode and "a:b:c:d:e:f:g:h" fields for e.g. the last operand in
      MOVI <Vd>.<T>, #<imm8> {, LSL #<amount>}.  */
-const char *
+bfd_boolean
 aarch64_ins_advsimd_imm_modified (const aarch64_operand *self ATTRIBUTE_UNUSED,
 				  const aarch64_opnd_info *info,
 				  aarch64_insn *code,
-				  const aarch64_inst *inst ATTRIBUTE_UNUSED)
+				  const aarch64_inst *inst ATTRIBUTE_UNUSED,
+				  aarch64_operand_error *errors
+					ATTRIBUTE_UNUSED)
 {
   enum aarch64_opnd_qualifier opnd0_qualifier = inst->operands[0].qualifier;
   uint64_t imm = info->imm.value;
@@ -417,7 +428,7 @@ aarch64_ins_advsimd_imm_modified (const aarch64_operand *self ATTRIBUTE_UNUSED,
   insert_fields (code, imm, 0, 2, FLD_defgh, FLD_abc);
 
   if (kind == AARCH64_MOD_NONE)
-    return NULL;
+    return TRUE;
 
   /* shift amount partially in cmode */
   assert (kind == AARCH64_MOD_LSL || kind == AARCH64_MOD_MSL);
@@ -429,7 +440,7 @@ aarch64_ins_advsimd_imm_modified (const aarch64_operand *self ATTRIBUTE_UNUSED,
       /* For 8-bit move immediate, the optional LSL #0 does not require
 	 encoding.  */
       if (esize == 1)
-	return NULL;
+	return TRUE;
       amount >>= 3;
       if (esize == 4)
 	gen_sub_field (FLD_cmode, 1, 2, &field);	/* per word */
@@ -444,74 +455,80 @@ aarch64_ins_advsimd_imm_modified (const aarch64_operand *self ATTRIBUTE_UNUSED,
     }
   insert_field_2 (&field, code, amount, 0);
 
-  return NULL;
+  return TRUE;
 }
 
 /* Insert fields for an 8-bit floating-point immediate.  */
-const char *
+bfd_boolean
 aarch64_ins_fpimm (const aarch64_operand *self, const aarch64_opnd_info *info,
 		   aarch64_insn *code,
-		   const aarch64_inst *inst ATTRIBUTE_UNUSED)
+		   const aarch64_inst *inst ATTRIBUTE_UNUSED,
+		   aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   insert_all_fields (self, code, info->imm.value);
-  return NULL;
+  return TRUE;
 }
 
 /* Insert 1-bit rotation immediate (#90 or #270).  */
-const char *
+bfd_boolean
 aarch64_ins_imm_rotate1 (const aarch64_operand *self,
 			 const aarch64_opnd_info *info,
-			 aarch64_insn *code, const aarch64_inst *inst)
+			 aarch64_insn *code, const aarch64_inst *inst,
+			 aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   uint64_t rot = (info->imm.value - 90) / 180;
   assert (rot < 2U);
   insert_field (self->fields[0], code, rot, inst->opcode->mask);
-  return NULL;
+  return TRUE;
 }
 
 /* Insert 2-bit rotation immediate (#0, #90, #180 or #270).  */
-const char *
+bfd_boolean
 aarch64_ins_imm_rotate2 (const aarch64_operand *self,
 			 const aarch64_opnd_info *info,
-			 aarch64_insn *code, const aarch64_inst *inst)
+			 aarch64_insn *code, const aarch64_inst *inst,
+			 aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   uint64_t rot = info->imm.value / 90;
   assert (rot < 4U);
   insert_field (self->fields[0], code, rot, inst->opcode->mask);
-  return NULL;
+  return TRUE;
 }
 
 /* Insert #<fbits> for the immediate operand in fp fix-point instructions,
    e.g.  SCVTF <Dd>, <Wn>, #<fbits>.  */
-const char *
+bfd_boolean
 aarch64_ins_fbits (const aarch64_operand *self, const aarch64_opnd_info *info,
 		   aarch64_insn *code,
-		   const aarch64_inst *inst ATTRIBUTE_UNUSED)
+		   const aarch64_inst *inst ATTRIBUTE_UNUSED,
+		   aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   insert_field (self->fields[0], code, 64 - info->imm.value, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Insert arithmetic immediate for e.g. the last operand in
      SUBS <Wd>, <Wn|WSP>, #<imm> {, <shift>}.  */
-const char *
+bfd_boolean
 aarch64_ins_aimm (const aarch64_operand *self, const aarch64_opnd_info *info,
-		  aarch64_insn *code, const aarch64_inst *inst ATTRIBUTE_UNUSED)
+		  aarch64_insn *code, const aarch64_inst *inst ATTRIBUTE_UNUSED,
+		  aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   /* shift */
   aarch64_insn value = info->shifter.amount ? 1 : 0;
   insert_field (self->fields[0], code, value, 0);
   /* imm12 (unsigned) */
   insert_field (self->fields[1], code, info->imm.value, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Common routine shared by aarch64_ins{,_inv}_limm.  INVERT_P says whether
    the operand should be inverted before encoding.  */
-static const char *
+static bfd_boolean
 aarch64_ins_limm_1 (const aarch64_operand *self,
 		    const aarch64_opnd_info *info, aarch64_insn *code,
-		    const aarch64_inst *inst, bfd_boolean invert_p)
+		    const aarch64_inst *inst, bfd_boolean invert_p,
+		    aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   aarch64_insn value;
   uint64_t imm = info->imm.value;
@@ -524,40 +541,43 @@ aarch64_ins_limm_1 (const aarch64_operand *self,
 
   insert_fields (code, value, 0, 3, self->fields[2], self->fields[1],
 		 self->fields[0]);
-  return NULL;
+  return TRUE;
 }
 
 /* Insert logical/bitmask immediate for e.g. the last operand in
      ORR <Wd|WSP>, <Wn>, #<imm>.  */
-const char *
+bfd_boolean
 aarch64_ins_limm (const aarch64_operand *self, const aarch64_opnd_info *info,
-		  aarch64_insn *code, const aarch64_inst *inst)
+		  aarch64_insn *code, const aarch64_inst *inst,
+		  aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   return aarch64_ins_limm_1 (self, info, code, inst,
-			     inst->opcode->op == OP_BIC);
+			     inst->opcode->op == OP_BIC, errors);
 }
 
 /* Insert a logical/bitmask immediate for the BIC alias of AND (etc.).  */
-const char *
+bfd_boolean
 aarch64_ins_inv_limm (const aarch64_operand *self,
 		      const aarch64_opnd_info *info, aarch64_insn *code,
-		      const aarch64_inst *inst)
+		      const aarch64_inst *inst,
+		      aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
-  return aarch64_ins_limm_1 (self, info, code, inst, TRUE);
+  return aarch64_ins_limm_1 (self, info, code, inst, TRUE, errors);
 }
 
 /* Encode Ft for e.g. STR <Qt>, [<Xn|SP>, <R><m>{, <extend> {<amount>}}]
    or LDP <Qt1>, <Qt2>, [<Xn|SP>], #<imm>.  */
-const char *
+bfd_boolean
 aarch64_ins_ft (const aarch64_operand *self, const aarch64_opnd_info *info,
-		aarch64_insn *code, const aarch64_inst *inst)
+		aarch64_insn *code, const aarch64_inst *inst,
+		aarch64_operand_error *errors)
 {
   aarch64_insn value = 0;
 
   assert (info->idx == 0);
 
   /* Rt */
-  aarch64_ins_regno (self, info, code, inst);
+  aarch64_ins_regno (self, info, code, inst, errors);
   if (inst->opcode->iclass == ldstpair_indexed
       || inst->opcode->iclass == ldstnapair_offs
       || inst->opcode->iclass == ldstpair_off
@@ -580,26 +600,28 @@ aarch64_ins_ft (const aarch64_operand *self, const aarch64_opnd_info *info,
       insert_fields (code, value, 0, 2, FLD_ldst_size, FLD_opc1);
     }
 
-  return NULL;
+  return TRUE;
 }
 
 /* Encode the address operand for e.g. STXRB <Ws>, <Wt>, [<Xn|SP>{,#0}].  */
-const char *
+bfd_boolean
 aarch64_ins_addr_simple (const aarch64_operand *self ATTRIBUTE_UNUSED,
 			 const aarch64_opnd_info *info, aarch64_insn *code,
-			 const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			 const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			 aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   /* Rn */
   insert_field (FLD_Rn, code, info->addr.base_regno, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode the address operand for e.g.
      STR <Qt>, [<Xn|SP>, <R><m>{, <extend> {<amount>}}].  */
-const char *
+bfd_boolean
 aarch64_ins_addr_regoff (const aarch64_operand *self ATTRIBUTE_UNUSED,
 			 const aarch64_opnd_info *info, aarch64_insn *code,
-			 const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			 const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			 aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   aarch64_insn S;
   enum aarch64_modifier_kind kind = info->shifter.kind;
@@ -624,15 +646,16 @@ aarch64_ins_addr_regoff (const aarch64_operand *self ATTRIBUTE_UNUSED,
     S = info->shifter.operator_present && info->shifter.amount_present;
   insert_field (FLD_S, code, S, 0);
 
-  return NULL;
+  return TRUE;
 }
 
 /* Encode the address operand for e.g.
      stlur <Xt>, [<Xn|SP>{, <amount>}].  */
-const char *
+bfd_boolean
 aarch64_ins_addr_offset (const aarch64_operand *self ATTRIBUTE_UNUSED,
 			 const aarch64_opnd_info *info, aarch64_insn *code,
-			 const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			 const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			 aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   /* Rn */
   insert_field (self->fields[0], code, info->addr.base_regno, 0);
@@ -647,15 +670,16 @@ aarch64_ins_addr_offset (const aarch64_operand *self ATTRIBUTE_UNUSED,
       assert (info->addr.preind == 1 && info->addr.postind == 0);
       insert_field (self->fields[2], code, 1, 0);
     }
-  return NULL;
+  return TRUE;
 }
 
 /* Encode the address operand for e.g. LDRSW <Xt>, [<Xn|SP>, #<simm>]!.  */
-const char *
+bfd_boolean
 aarch64_ins_addr_simm (const aarch64_operand *self,
 		       const aarch64_opnd_info *info,
 		       aarch64_insn *code,
-		       const aarch64_inst *inst ATTRIBUTE_UNUSED)
+		       const aarch64_inst *inst ATTRIBUTE_UNUSED,
+		       aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   int imm;
 
@@ -679,15 +703,16 @@ aarch64_ins_addr_simm (const aarch64_operand *self,
 	insert_field (self->fields[1], code, 1, 0);
     }
 
-  return NULL;
+  return TRUE;
 }
 
 /* Encode the address operand for e.g. LDRAA <Xt>, [<Xn|SP>{, #<simm>}].  */
-const char *
+bfd_boolean
 aarch64_ins_addr_simm10 (const aarch64_operand *self,
 			 const aarch64_opnd_info *info,
 			 aarch64_insn *code,
-			 const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			 const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			 aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   int imm;
 
@@ -703,15 +728,16 @@ aarch64_ins_addr_simm10 (const aarch64_operand *self,
       assert (info->addr.preind == 1 && info->addr.postind == 0);
       insert_field (self->fields[3], code, 1, 0);
     }
-  return NULL;
+  return TRUE;
 }
 
 /* Encode the address operand for e.g. LDRSW <Xt>, [<Xn|SP>{, #<pimm>}].  */
-const char *
+bfd_boolean
 aarch64_ins_addr_uimm12 (const aarch64_operand *self,
 			 const aarch64_opnd_info *info,
 			 aarch64_insn *code,
-			 const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			 const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			 aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   int shift = get_logsz (aarch64_get_qualifier_esize (info->qualifier));
 
@@ -719,15 +745,16 @@ aarch64_ins_addr_uimm12 (const aarch64_operand *self,
   insert_field (self->fields[0], code, info->addr.base_regno, 0);
   /* uimm12 */
   insert_field (self->fields[1], code,info->addr.offset.imm >> shift, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode the address operand for e.g.
      LD1 {<Vt>.<T>, <Vt2>.<T>, <Vt3>.<T>}, [<Xn|SP>], <Xm|#<amount>>.  */
-const char *
+bfd_boolean
 aarch64_ins_simd_addr_post (const aarch64_operand *self ATTRIBUTE_UNUSED,
 			    const aarch64_opnd_info *info, aarch64_insn *code,
-			    const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			    const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			    aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   /* Rn */
   insert_field (FLD_Rn, code, info->addr.base_regno, 0);
@@ -736,100 +763,108 @@ aarch64_ins_simd_addr_post (const aarch64_operand *self ATTRIBUTE_UNUSED,
     insert_field (FLD_Rm, code, info->addr.offset.regno, 0);
   else
     insert_field (FLD_Rm, code, 0x1f, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode the condition operand for e.g. CSEL <Xd>, <Xn>, <Xm>, <cond>.  */
-const char *
+bfd_boolean
 aarch64_ins_cond (const aarch64_operand *self ATTRIBUTE_UNUSED,
 		  const aarch64_opnd_info *info, aarch64_insn *code,
-		  const aarch64_inst *inst ATTRIBUTE_UNUSED)
+		  const aarch64_inst *inst ATTRIBUTE_UNUSED,
+		  aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   /* cond */
   insert_field (FLD_cond, code, info->cond->value, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode the system register operand for e.g. MRS <Xt>, <systemreg>.  */
-const char *
+bfd_boolean
 aarch64_ins_sysreg (const aarch64_operand *self ATTRIBUTE_UNUSED,
 		    const aarch64_opnd_info *info, aarch64_insn *code,
-		    const aarch64_inst *inst ATTRIBUTE_UNUSED)
+		    const aarch64_inst *inst,
+		    aarch64_operand_error *detail ATTRIBUTE_UNUSED)
 {
   /* op0:op1:CRn:CRm:op2 */
-  insert_fields (code, info->sysreg, inst->opcode->mask, 5,
+  insert_fields (code, info->sysreg.value, inst->opcode->mask, 5,
 		 FLD_op2, FLD_CRm, FLD_CRn, FLD_op1, FLD_op0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode the PSTATE field operand for e.g. MSR <pstatefield>, #<imm>.  */
-const char *
+bfd_boolean
 aarch64_ins_pstatefield (const aarch64_operand *self ATTRIBUTE_UNUSED,
 			 const aarch64_opnd_info *info, aarch64_insn *code,
-			 const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			 const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			 aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   /* op1:op2 */
   insert_fields (code, info->pstatefield, inst->opcode->mask, 2,
 		 FLD_op2, FLD_op1);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode the system instruction op operand for e.g. AT <at_op>, <Xt>.  */
-const char *
+bfd_boolean
 aarch64_ins_sysins_op (const aarch64_operand *self ATTRIBUTE_UNUSED,
 		       const aarch64_opnd_info *info, aarch64_insn *code,
-		       const aarch64_inst *inst ATTRIBUTE_UNUSED)
+		       const aarch64_inst *inst ATTRIBUTE_UNUSED,
+		       aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   /* op1:CRn:CRm:op2 */
   insert_fields (code, info->sysins_op->value, inst->opcode->mask, 4,
 		 FLD_op2, FLD_CRm, FLD_CRn, FLD_op1);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode the memory barrier option operand for e.g. DMB <option>|#<imm>.  */
 
-const char *
+bfd_boolean
 aarch64_ins_barrier (const aarch64_operand *self ATTRIBUTE_UNUSED,
 		     const aarch64_opnd_info *info, aarch64_insn *code,
-		     const aarch64_inst *inst ATTRIBUTE_UNUSED)
+		     const aarch64_inst *inst ATTRIBUTE_UNUSED,
+		     aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   /* CRm */
   insert_field (FLD_CRm, code, info->barrier->value, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode the prefetch operation option operand for e.g.
      PRFM <prfop>, [<Xn|SP>{, #<pimm>}].  */
 
-const char *
+bfd_boolean
 aarch64_ins_prfop (const aarch64_operand *self ATTRIBUTE_UNUSED,
 		   const aarch64_opnd_info *info, aarch64_insn *code,
-		   const aarch64_inst *inst ATTRIBUTE_UNUSED)
+		   const aarch64_inst *inst ATTRIBUTE_UNUSED,
+		   aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   /* prfop in Rt */
   insert_field (FLD_Rt, code, info->prfop->value, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode the hint number for instructions that alias HINT but take an
    operand.  */
 
-const char *
+bfd_boolean
 aarch64_ins_hint (const aarch64_operand *self ATTRIBUTE_UNUSED,
 		  const aarch64_opnd_info *info, aarch64_insn *code,
-		  const aarch64_inst *inst ATTRIBUTE_UNUSED)
+		  const aarch64_inst *inst ATTRIBUTE_UNUSED,
+		  aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   /* CRm:op2.  */
   insert_fields (code, info->hint_option->value, 0, 2, FLD_op2, FLD_CRm);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode the extended register operand for e.g.
      STR <Qt>, [<Xn|SP>, <R><m>{, <extend> {<amount>}}].  */
-const char *
+bfd_boolean
 aarch64_ins_reg_extended (const aarch64_operand *self ATTRIBUTE_UNUSED,
 			  const aarch64_opnd_info *info, aarch64_insn *code,
-			  const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			  const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			  aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   enum aarch64_modifier_kind kind;
 
@@ -844,15 +879,16 @@ aarch64_ins_reg_extended (const aarch64_operand *self ATTRIBUTE_UNUSED,
   /* imm3 */
   insert_field (FLD_imm3, code, info->shifter.amount, 0);
 
-  return NULL;
+  return TRUE;
 }
 
 /* Encode the shifted register operand for e.g.
      SUBS <Xd>, <Xn>, <Xm> {, <shift> #<amount>}.  */
-const char *
+bfd_boolean
 aarch64_ins_reg_shifted (const aarch64_operand *self ATTRIBUTE_UNUSED,
 			 const aarch64_opnd_info *info, aarch64_insn *code,
-			 const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			 const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			 aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   /* Rm */
   insert_field (FLD_Rm, code, info->reg.regno, 0);
@@ -862,39 +898,41 @@ aarch64_ins_reg_shifted (const aarch64_operand *self ATTRIBUTE_UNUSED,
   /* imm6 */
   insert_field (FLD_imm6, code, info->shifter.amount, 0);
 
-  return NULL;
+  return TRUE;
 }
 
 /* Encode an SVE address [<base>, #<simm4>*<factor>, MUL VL],
    where <simm4> is a 4-bit signed value and where <factor> is 1 plus
    SELF's operand-dependent value.  fields[0] specifies the field that
    holds <base>.  <simm4> is encoded in the SVE_imm4 field.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_addr_ri_s4xvl (const aarch64_operand *self,
 			       const aarch64_opnd_info *info,
 			       aarch64_insn *code,
-			       const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			       const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			       aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   int factor = 1 + get_operand_specific_data (self);
   insert_field (self->fields[0], code, info->addr.base_regno, 0);
   insert_field (FLD_SVE_imm4, code, info->addr.offset.imm / factor, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode an SVE address [<base>, #<simm6>*<factor>, MUL VL],
    where <simm6> is a 6-bit signed value and where <factor> is 1 plus
    SELF's operand-dependent value.  fields[0] specifies the field that
    holds <base>.  <simm6> is encoded in the SVE_imm6 field.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_addr_ri_s6xvl (const aarch64_operand *self,
 			       const aarch64_opnd_info *info,
 			       aarch64_insn *code,
-			       const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			       const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			       aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   int factor = 1 + get_operand_specific_data (self);
   insert_field (self->fields[0], code, info->addr.base_regno, 0);
   insert_field (FLD_SVE_imm6, code, info->addr.offset.imm / factor, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode an SVE address [<base>, #<simm9>*<factor>, MUL VL],
@@ -902,68 +940,73 @@ aarch64_ins_sve_addr_ri_s6xvl (const aarch64_operand *self,
    SELF's operand-dependent value.  fields[0] specifies the field that
    holds <base>.  <simm9> is encoded in the concatenation of the SVE_imm6
    and imm3 fields, with imm3 being the less-significant part.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_addr_ri_s9xvl (const aarch64_operand *self,
 			       const aarch64_opnd_info *info,
 			       aarch64_insn *code,
-			       const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			       const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			       aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   int factor = 1 + get_operand_specific_data (self);
   insert_field (self->fields[0], code, info->addr.base_regno, 0);
   insert_fields (code, info->addr.offset.imm / factor, 0,
 		 2, FLD_imm3, FLD_SVE_imm6);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode an SVE address [X<n>, #<SVE_imm4> << <shift>], where <SVE_imm4>
    is a 4-bit signed number and where <shift> is SELF's operand-dependent
    value.  fields[0] specifies the base register field.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_addr_ri_s4 (const aarch64_operand *self,
 			    const aarch64_opnd_info *info, aarch64_insn *code,
-			    const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			    const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			    aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   int factor = 1 << get_operand_specific_data (self);
   insert_field (self->fields[0], code, info->addr.base_regno, 0);
   insert_field (FLD_SVE_imm4, code, info->addr.offset.imm / factor, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode an SVE address [X<n>, #<SVE_imm6> << <shift>], where <SVE_imm6>
    is a 6-bit unsigned number and where <shift> is SELF's operand-dependent
    value.  fields[0] specifies the base register field.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_addr_ri_u6 (const aarch64_operand *self,
 			    const aarch64_opnd_info *info, aarch64_insn *code,
-			    const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			    const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			    aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   int factor = 1 << get_operand_specific_data (self);
   insert_field (self->fields[0], code, info->addr.base_regno, 0);
   insert_field (FLD_SVE_imm6, code, info->addr.offset.imm / factor, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode an SVE address [X<n>, X<m>{, LSL #<shift>}], where <shift>
    is SELF's operand-dependent value.  fields[0] specifies the base
    register field and fields[1] specifies the offset register field.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_addr_rr_lsl (const aarch64_operand *self,
 			     const aarch64_opnd_info *info, aarch64_insn *code,
-			     const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			     const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			     aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   insert_field (self->fields[0], code, info->addr.base_regno, 0);
   insert_field (self->fields[1], code, info->addr.offset.regno, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode an SVE address [X<n>, Z<m>.<T>, (S|U)XTW {#<shift>}], where
    <shift> is SELF's operand-dependent value.  fields[0] specifies the
    base register field, fields[1] specifies the offset register field and
    fields[2] is a single-bit field that selects SXTW over UXTW.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_addr_rz_xtw (const aarch64_operand *self,
 			     const aarch64_opnd_info *info, aarch64_insn *code,
-			     const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			     const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			     aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   insert_field (self->fields[0], code, info->addr.base_regno, 0);
   insert_field (self->fields[1], code, info->addr.offset.regno, 0);
@@ -971,77 +1014,83 @@ aarch64_ins_sve_addr_rz_xtw (const aarch64_operand *self,
     insert_field (self->fields[2], code, 0, 0);
   else
     insert_field (self->fields[2], code, 1, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode an SVE address [Z<n>.<T>, #<imm5> << <shift>], where <imm5> is a
    5-bit unsigned number and where <shift> is SELF's operand-dependent value.
    fields[0] specifies the base register field.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_addr_zi_u5 (const aarch64_operand *self,
 			    const aarch64_opnd_info *info, aarch64_insn *code,
-			    const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			    const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			    aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   int factor = 1 << get_operand_specific_data (self);
   insert_field (self->fields[0], code, info->addr.base_regno, 0);
   insert_field (FLD_imm5, code, info->addr.offset.imm / factor, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode an SVE address [Z<n>.<T>, Z<m>.<T>{, <modifier> {#<msz>}}],
    where <modifier> is fixed by the instruction and where <msz> is a
    2-bit unsigned number.  fields[0] specifies the base register field
    and fields[1] specifies the offset register field.  */
-static const char *
+static bfd_boolean
 aarch64_ext_sve_addr_zz (const aarch64_operand *self,
-			 const aarch64_opnd_info *info, aarch64_insn *code)
+			 const aarch64_opnd_info *info, aarch64_insn *code,
+			 aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   insert_field (self->fields[0], code, info->addr.base_regno, 0);
   insert_field (self->fields[1], code, info->addr.offset.regno, 0);
   insert_field (FLD_SVE_msz, code, info->shifter.amount, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode an SVE address [Z<n>.<T>, Z<m>.<T>{, LSL #<msz>}], where
    <msz> is a 2-bit unsigned number.  fields[0] specifies the base register
    field and fields[1] specifies the offset register field.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_addr_zz_lsl (const aarch64_operand *self,
 			     const aarch64_opnd_info *info, aarch64_insn *code,
-			     const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			     const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			     aarch64_operand_error *errors)
 {
-  return aarch64_ext_sve_addr_zz (self, info, code);
+  return aarch64_ext_sve_addr_zz (self, info, code, errors);
 }
 
 /* Encode an SVE address [Z<n>.<T>, Z<m>.<T>, SXTW {#<msz>}], where
    <msz> is a 2-bit unsigned number.  fields[0] specifies the base register
    field and fields[1] specifies the offset register field.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_addr_zz_sxtw (const aarch64_operand *self,
 			      const aarch64_opnd_info *info,
 			      aarch64_insn *code,
-			      const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			      const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			      aarch64_operand_error *errors)
 {
-  return aarch64_ext_sve_addr_zz (self, info, code);
+  return aarch64_ext_sve_addr_zz (self, info, code, errors);
 }
 
 /* Encode an SVE address [Z<n>.<T>, Z<m>.<T>, UXTW {#<msz>}], where
    <msz> is a 2-bit unsigned number.  fields[0] specifies the base register
    field and fields[1] specifies the offset register field.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_addr_zz_uxtw (const aarch64_operand *self,
 			      const aarch64_opnd_info *info,
 			      aarch64_insn *code,
-			      const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			      const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			      aarch64_operand_error *errors)
 {
-  return aarch64_ext_sve_addr_zz (self, info, code);
+  return aarch64_ext_sve_addr_zz (self, info, code, errors);
 }
 
 /* Encode an SVE ADD/SUB immediate.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_aimm (const aarch64_operand *self,
 		      const aarch64_opnd_info *info, aarch64_insn *code,
-		      const aarch64_inst *inst ATTRIBUTE_UNUSED)
+		      const aarch64_inst *inst ATTRIBUTE_UNUSED,
+		      aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   if (info->shifter.amount == 8)
     insert_all_fields (self, code, (info->imm.value & 0xff) | 256);
@@ -1049,87 +1098,94 @@ aarch64_ins_sve_aimm (const aarch64_operand *self,
     insert_all_fields (self, code, ((info->imm.value / 256) & 0xff) | 256);
   else
     insert_all_fields (self, code, info->imm.value & 0xff);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode an SVE CPY/DUP immediate.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_asimm (const aarch64_operand *self,
 		       const aarch64_opnd_info *info, aarch64_insn *code,
-		       const aarch64_inst *inst)
+		       const aarch64_inst *inst,
+		       aarch64_operand_error *errors)
 {
-  return aarch64_ins_sve_aimm (self, info, code, inst);
+  return aarch64_ins_sve_aimm (self, info, code, inst, errors);
 }
 
 /* Encode Zn[MM], where MM has a 7-bit triangular encoding.  The fields
    array specifies which field to use for Zn.  MM is encoded in the
    concatenation of imm5 and SVE_tszh, with imm5 being the less
    significant part.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_index (const aarch64_operand *self,
 		       const aarch64_opnd_info *info, aarch64_insn *code,
-		       const aarch64_inst *inst ATTRIBUTE_UNUSED)
+		       const aarch64_inst *inst ATTRIBUTE_UNUSED,
+		       aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   unsigned int esize = aarch64_get_qualifier_esize (info->qualifier);
   insert_field (self->fields[0], code, info->reglane.regno, 0);
   insert_fields (code, (info->reglane.index * 2 + 1) * esize, 0,
 		 2, FLD_imm5, FLD_SVE_tszh);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode a logical/bitmask immediate for the MOV alias of SVE DUPM.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_limm_mov (const aarch64_operand *self,
 			  const aarch64_opnd_info *info, aarch64_insn *code,
-			  const aarch64_inst *inst)
+			  const aarch64_inst *inst,
+			  aarch64_operand_error *errors)
 {
-  return aarch64_ins_limm (self, info, code, inst);
+  return aarch64_ins_limm (self, info, code, inst, errors);
 }
 
 /* Encode Zn[MM], where Zn occupies the least-significant part of the field
    and where MM occupies the most-significant part.  The operand-dependent
    value specifies the number of bits in Zn.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_quad_index (const aarch64_operand *self,
 			    const aarch64_opnd_info *info, aarch64_insn *code,
-			    const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			    const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			    aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   unsigned int reg_bits = get_operand_specific_data (self);
   assert (info->reglane.regno < (1U << reg_bits));
   unsigned int val = (info->reglane.index << reg_bits) + info->reglane.regno;
   insert_all_fields (self, code, val);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode {Zn.<T> - Zm.<T>}.  The fields array specifies which field
    to use for Zn.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_reglist (const aarch64_operand *self,
 			 const aarch64_opnd_info *info, aarch64_insn *code,
-			 const aarch64_inst *inst ATTRIBUTE_UNUSED)
+			 const aarch64_inst *inst ATTRIBUTE_UNUSED,
+			 aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   insert_field (self->fields[0], code, info->reglist.first_regno, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode <pattern>{, MUL #<amount>}.  The fields array specifies which
    fields to use for <pattern>.  <amount> - 1 is encoded in the SVE_imm4
    field.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_scale (const aarch64_operand *self,
 		       const aarch64_opnd_info *info, aarch64_insn *code,
-		       const aarch64_inst *inst ATTRIBUTE_UNUSED)
+		       const aarch64_inst *inst ATTRIBUTE_UNUSED,
+		       aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   insert_all_fields (self, code, info->imm.value);
   insert_field (FLD_SVE_imm4, code, info->shifter.amount - 1, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode an SVE shift left immediate.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_shlimm (const aarch64_operand *self,
 			const aarch64_opnd_info *info, aarch64_insn *code,
-			const aarch64_inst *inst)
+			const aarch64_inst *inst,
+			aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   const aarch64_opnd_info *prev_operand;
   unsigned int esize;
@@ -1138,14 +1194,15 @@ aarch64_ins_sve_shlimm (const aarch64_operand *self,
   prev_operand = &inst->operands[info->idx - 1];
   esize = aarch64_get_qualifier_esize (prev_operand->qualifier);
   insert_all_fields (self, code, 8 * esize + info->imm.value);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode an SVE shift right immediate.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_shrimm (const aarch64_operand *self,
 			const aarch64_opnd_info *info, aarch64_insn *code,
-			const aarch64_inst *inst)
+			const aarch64_inst *inst,
+			aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   const aarch64_opnd_info *prev_operand;
   unsigned int esize;
@@ -1154,52 +1211,55 @@ aarch64_ins_sve_shrimm (const aarch64_operand *self,
   prev_operand = &inst->operands[info->idx - 1];
   esize = aarch64_get_qualifier_esize (prev_operand->qualifier);
   insert_all_fields (self, code, 16 * esize - info->imm.value);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode a single-bit immediate that selects between #0.5 and #1.0.
    The fields array specifies which field to use.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_float_half_one (const aarch64_operand *self,
 				const aarch64_opnd_info *info,
 				aarch64_insn *code,
-				const aarch64_inst *inst ATTRIBUTE_UNUSED)
+				const aarch64_inst *inst ATTRIBUTE_UNUSED,
+				aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   if (info->imm.value == 0x3f000000)
     insert_field (self->fields[0], code, 0, 0);
   else
     insert_field (self->fields[0], code, 1, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode a single-bit immediate that selects between #0.5 and #2.0.
    The fields array specifies which field to use.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_float_half_two (const aarch64_operand *self,
 				const aarch64_opnd_info *info,
 				aarch64_insn *code,
-				const aarch64_inst *inst ATTRIBUTE_UNUSED)
+				const aarch64_inst *inst ATTRIBUTE_UNUSED,
+				aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   if (info->imm.value == 0x3f000000)
     insert_field (self->fields[0], code, 0, 0);
   else
     insert_field (self->fields[0], code, 1, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Encode a single-bit immediate that selects between #0.0 and #1.0.
    The fields array specifies which field to use.  */
-const char *
+bfd_boolean
 aarch64_ins_sve_float_zero_one (const aarch64_operand *self,
 				const aarch64_opnd_info *info,
 				aarch64_insn *code,
-				const aarch64_inst *inst ATTRIBUTE_UNUSED)
+				const aarch64_inst *inst ATTRIBUTE_UNUSED,
+				aarch64_operand_error *errors ATTRIBUTE_UNUSED)
 {
   if (info->imm.value == 0)
     insert_field (self->fields[0], code, 0, 0);
   else
     insert_field (self->fields[0], code, 1, 0);
-  return NULL;
+  return TRUE;
 }
 
 /* Miscellaneous encoding functions.  */
@@ -1853,7 +1913,7 @@ convert_to_real_return:
    Return the encoded result in *CODE and if QLF_SEQ is not NULL, return the
    matched operand qualifier sequence in *QLF_SEQ.  */
 
-int
+bfd_boolean
 aarch64_opcode_encode (const aarch64_opcode *opcode,
 		       const aarch64_inst *inst_ori, aarch64_insn *code,
 		       aarch64_opnd_qualifier_t *qlf_seq,
@@ -1930,8 +1990,10 @@ aarch64_opcode_encode (const aarch64_opcode *opcode,
 	  continue;
 	}
       opnd = &aarch64_operands[type];
-      if (operand_has_inserter (opnd))
-	aarch64_insert_operand (opnd, info, &inst->value, inst);
+      if (operand_has_inserter (opnd)
+	  && !aarch64_insert_operand (opnd, info, &inst->value, inst,
+				      mismatch_detail))
+	    return FALSE;
     }
 
   /* Call opcode encoders indicated by flags.  */
@@ -1947,5 +2009,5 @@ encoding_exit:
 
   *code = inst->value;
 
-  return 1;
+  return TRUE;
 }