i386: Check invalid (%dx) usage

(%dx) isn't a valid memory address in any modes.  It is used as a special
memory operand for input/output port address in AT&T syntax and should
only be used with input/output instructions.  Update i386_att_operand to
set i.input_output_operand to true for (%dx) and issue an error if (%dx)
is used with non-input/output instructions.

	PR gas/29751
	* config/tc-i386.c (_i386_insn): Add input_output_operand.
	(md_assemble): Issue an error if input/output memory operand is
	used with non-input/output instructions.
	(i386_att_operand): Set i.input_output_operand to true for
	(%dx).
	* testsuite/gas/i386/inval.l: Updated.
	* testsuite/gas/i386/x86-64-inval.l: Likewise.
	* testsuite/gas/i386/inval.s: Add tests for invalid (%dx) usage.
	* testsuite/gas/i386/x86-64-inval.s: Likewise.

1 files changed, 16 insertions, 0 deletions

diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index da005c5..142b937 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -311,6 +311,10 @@ struct _i386_insn
     /* The operand to a branch insn indicates an absolute branch.  */
     bool jumpabsolute;
 
+    /* There is a memory operand of (%dx) which should be only used
+       with input/output instructions.  */
+    bool input_output_operand;
+
     /* Extended states.  */
     enum
       {
@@ -5045,6 +5049,17 @@ md_assemble (char *line)
       i.disp_operands = 0;
     }
 
+  /* The memory operand of (%dx) should be only used with input/output
+     instructions (base opcodes: 0x6c, 0x6e, 0xec, 0xee).  */
+  if (i.input_output_operand
+      && ((i.tm.base_opcode | 0x82) != 0xee
+	  || i.tm.opcode_modifier.opcodespace != SPACE_BASE))
+    {
+      as_bad (_("input/output port address isn't allowed with `%s'"),
+	      i.tm.name);
+      return;
+    }
+
   if (optimize && !i.no_optimize && i.tm.opcode_modifier.optimize)
     optimize_encoding ();
 
@@ -11752,6 +11767,7 @@ i386_att_operand (char *operand_string)
 	  && !operand_type_check (i.types[this_operand], disp))
 	{
 	  i.types[this_operand] = i.base_reg->reg_type;
+	  i.input_output_operand = true;
 	  return 1;
 	}