aarch64: Add support for vgx2 and vgx4

Many SME2 instructions operate on groups of 2 or 4 ZA vectors.
This is indicated by adding a "vgx2" or "vgx4" group size to the
ZA index.  The group size is optional in assembly but preferred
for disassembly.

There is not a binary distinction between mnemonics that have
group sizes and mnemonics that don't, nor between mnemonics that
take vgx2 and mnemonics that take vgx4.  We therefore get better
error messages if we allow any ZA index to have a group size
during parsing, and wait until constraint checking to reject
invalid sizes.

A quirk of the way errors are reported means that if an instruction
is wrong both in its qualifiers and its use of a group size, we'll
print suggested alternative instructions that also have an incorrect
group size.  But that's a general property that also applies to
things like out-of-range immediates.  It's also not obviously the
wrong thing to do.  We need to be relatively confident that we're
looking at the right opcode before reporting detailed operand-specific
errors, so doing qualifier checking first seems resonable.

1 files changed, 41 insertions, 8 deletions

diff --git a/opcodes/aarch64-opc.c b/opcodes/aarch64-opc.c
index e97201b..0d38ff2 100644
--- a/opcodes/aarch64-opc.c
+++ b/opcodes/aarch64-opc.c
@@ -1459,6 +1459,16 @@ set_reg_list_stride_error (aarch64_operand_error *mismatch_detail, int idx,
 }
 
 static inline void
+set_invalid_vg_size (aarch64_operand_error *mismatch_detail,
+		     int idx, int expected)
+{
+  if (mismatch_detail == NULL)
+    return;
+  set_error (mismatch_detail, AARCH64_OPDE_INVALID_VG_SIZE, idx, NULL);
+  mismatch_detail->data[0].i = expected;
+}
+
+static inline void
 set_other_error (aarch64_operand_error *mismatch_detail, int idx,
 		 const char* error)
 {
@@ -1517,12 +1527,14 @@ check_reglist (const aarch64_opnd_info *opnd,
 
    - a selection register in the range [MIN_WREG, MIN_WREG + 3]
 
-   - an immediate offset in the range [0, MAX_VALUE].  */
+   - an immediate offset in the range [0, MAX_VALUE].
+
+   - a vector group size of GROUP_SIZE.  */
 
 static bool
 check_za_access (const aarch64_opnd_info *opnd,
 		 aarch64_operand_error *mismatch_detail, int idx,
-		 int min_wreg, int max_value)
+		 int min_wreg, int max_value, int group_size)
 {
   if (!value_in_range_p (opnd->indexed_za.index.regno, min_wreg, min_wreg + 3))
     {
@@ -1540,6 +1552,15 @@ check_za_access (const aarch64_opnd_info *opnd,
       set_offset_out_of_range_error (mismatch_detail, idx, 0, max_value);
       return false;
     }
+
+  /* The vector group specifier is optional in assembly code.  */
+  if (opnd->indexed_za.group_size != 0
+      && opnd->indexed_za.group_size != group_size)
+    {
+      set_invalid_vg_size (mismatch_detail, idx, group_size);
+      return false;
+    }
+
   return true;
 }
 
@@ -1657,7 +1678,7 @@ operand_general_constraint_met_p (const aarch64_opnd_info *opnds, int idx,
 	case AARCH64_OPND_SME_PnT_Wm_imm:
 	  size = aarch64_get_qualifier_esize (opnd->qualifier);
 	  max_value = 16 / size - 1;
-	  if (!check_za_access (opnd, mismatch_detail, idx, 12, max_value))
+	  if (!check_za_access (opnd, mismatch_detail, idx, 12, max_value, 0))
 	    return 0;
 	  break;
 
@@ -1680,12 +1701,14 @@ operand_general_constraint_met_p (const aarch64_opnd_info *opnds, int idx,
 	case AARCH64_OPND_SME_ZA_HV_idx_ldstr:
 	  size = aarch64_get_qualifier_esize (opnd->qualifier);
 	  max_value = 16 / size - 1;
-	  if (!check_za_access (opnd, mismatch_detail, idx, 12, max_value))
+	  if (!check_za_access (opnd, mismatch_detail, idx, 12, max_value,
+				get_opcode_dependent_value (opcode)))
 	    return 0;
 	  break;
 
 	case AARCH64_OPND_SME_ZA_array_off4:
-	  if (!check_za_access (opnd, mismatch_detail, idx, 12, 15))
+	  if (!check_za_access (opnd, mismatch_detail, idx, 12, 15,
+				get_opcode_dependent_value (opcode)))
 	    return 0;
 	  break;
 
@@ -3671,7 +3694,7 @@ aarch64_print_operand (char *buf, size_t size, bfd_vma pc,
     case AARCH64_OPND_SME_ZA_HV_idx_src:
     case AARCH64_OPND_SME_ZA_HV_idx_dest:
     case AARCH64_OPND_SME_ZA_HV_idx_ldstr:
-      snprintf (buf, size, "%s%s[%s, %s]%s",
+      snprintf (buf, size, "%s%s[%s, %s%s%s]%s",
 		opnd->type == AARCH64_OPND_SME_ZA_HV_idx_ldstr ? "{" : "",
 		style_reg (styler, "za%d%c.%s",
 			   opnd->indexed_za.regno,
@@ -3679,6 +3702,11 @@ aarch64_print_operand (char *buf, size_t size, bfd_vma pc,
 			   aarch64_get_qualifier_name (opnd->qualifier)),
 		style_reg (styler, "w%d", opnd->indexed_za.index.regno),
 		style_imm (styler, "%" PRIi64, opnd->indexed_za.index.imm),
+		opnd->indexed_za.group_size ? ", " : "",
+		opnd->indexed_za.group_size == 2
+		? style_sub_mnem (styler, "vgx2")
+		: opnd->indexed_za.group_size == 4
+		? style_sub_mnem (styler, "vgx4") : "",
 		opnd->type == AARCH64_OPND_SME_ZA_HV_idx_ldstr ? "}" : "");
       break;
 
@@ -3687,10 +3715,15 @@ aarch64_print_operand (char *buf, size_t size, bfd_vma pc,
       break;
 
     case AARCH64_OPND_SME_ZA_array_off4:
-      snprintf (buf, size, "%s[%s, %s]",
+      snprintf (buf, size, "%s[%s, %s%s%s]",
 		style_reg (styler, "za"),
 		style_reg (styler, "w%d", opnd->indexed_za.index.regno),
-		style_imm (styler, "%" PRIi64, opnd->indexed_za.index.imm));
+		style_imm (styler, "%" PRIi64, opnd->indexed_za.index.imm),
+		opnd->indexed_za.group_size ? ", " : "",
+		opnd->indexed_za.group_size == 2
+		? style_sub_mnem (styler, "vgx2")
+		: opnd->indexed_za.group_size == 4
+		? style_sub_mnem (styler, "vgx4") : "");
       break;
 
     case AARCH64_OPND_SME_SM_ZA: