S/390: Improve error checking for optional operands

So far we only had an instruction flag which made an arbitrary number
of operands optional.  This limits error checking capabilities for
instructions marked that way.  With this patch the optparm flag only
allows a single optional parameter and another one is added (optparm2)
allowing 2 optional arguments.  Hopefully we won't need more than that
in the future. So far there will be only a single use of optparm2.

gas/ChangeLog:

2017-05-30  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* config/tc-s390.c (md_gather_operands): Support new optparm2
	instruction flag.

include/ChangeLog:

2017-05-30  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* opcode/s390.h: Add new instruction flags optparm2.

opcodes/ChangeLog:

2017-05-30  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* s390-dis.c (s390_print_insn_with_opcode): Support new optparm2
	instruction flag.
	* s390-mkopc.c (main): Recognize the new instruction flag when
	parsing instruction list.

4 files changed, 34 insertions, 8 deletions

diff --git a/gas/config/tc-s390.c b/gas/config/tc-s390.c
index a31cb3a7673..043336e954e 100644
--- a/gas/config/tc-s390.c
+++ b/gas/config/tc-s390.c
@@ -1270,7 +1270,8 @@ md_gather_operands (char *str,
 
       operand = s390_operands + *opindex_ptr;
 
-      if ((opcode->flags & S390_INSTR_FLAG_OPTPARM) && *str == '\0')
+      if ((opcode->flags & (S390_INSTR_FLAG_OPTPARM | S390_INSTR_FLAG_OPTPARM2))
+	  && *str == '\0')
 	{
 	  /* Optional parameters might need to be ORed with a
 	     value so calling s390_insert_operand is needed.  */
@@ -1536,7 +1537,18 @@ md_gather_operands (char *str,
 	      str++;
 	    }
 
-	  if ((opcode->flags & S390_INSTR_FLAG_OPTPARM) && *str == '\0')
+	  if ((opcode->flags & (S390_INSTR_FLAG_OPTPARM
+				| S390_INSTR_FLAG_OPTPARM2))
+	      && opindex_ptr[1] != '\0'
+	      && opindex_ptr[2] == '\0'
+	      && *str == '\0')
+	    continue;
+
+	    if ((opcode->flags & S390_INSTR_FLAG_OPTPARM2)
+		&& opindex_ptr[1] != '\0'
+		&& opindex_ptr[2] != '\0'
+		&& opindex_ptr[3] == '\0'
+		&& *str == '\0')
 	    continue;
 
 	  /* If there is a next operand it must be separated by a comma.  */
diff --git a/include/opcode/s390.h b/include/opcode/s390.h
index a2d42e0fb62..b4a0a8fac43 100644
--- a/include/opcode/s390.h
+++ b/include/opcode/s390.h
@@ -48,10 +48,11 @@ enum s390_opcode_cpu_val
 
 /* Instruction specific flags.  */
 #define S390_INSTR_FLAG_OPTPARM 0x1
+#define S390_INSTR_FLAG_OPTPARM2 0x2
 
-#define S390_INSTR_FLAG_HTM 0x2
-#define S390_INSTR_FLAG_VX 0x4
-#define S390_INSTR_FLAG_FACILITY_MASK 0x6
+#define S390_INSTR_FLAG_HTM 0x4
+#define S390_INSTR_FLAG_VX 0x8
+#define S390_INSTR_FLAG_FACILITY_MASK 0xc
 
 /* The opcode table is an array of struct s390_opcode.  */
 
diff --git a/opcodes/s390-dis.c b/opcodes/s390-dis.c
index 8d450b4664e..16bb5ff7c59 100644
--- a/opcodes/s390-dis.c
+++ b/opcodes/s390-dis.c
@@ -206,11 +206,20 @@ s390_print_insn_with_opcode (bfd_vma memaddr,
 
       /* For instructions with a last optional operand don't print it
 	 if zero.  */
-      if ((opcode->flags & S390_INSTR_FLAG_OPTPARM)
+      if ((opcode->flags & (S390_INSTR_FLAG_OPTPARM | S390_INSTR_FLAG_OPTPARM2))
 	  && val.u == 0
 	  && opindex[1] == 0)
 	break;
 
+      if ((opcode->flags & S390_INSTR_FLAG_OPTPARM2)
+	  && val.u == 0 && opindex[1] != 0 && opindex[2] == 0)
+	{
+	  union operand_value next_op_val =
+	    s390_extract_operand (buffer, s390_operands + opindex[1]);
+	  if (next_op_val.u == 0)
+	    break;
+	}
+
       if (flags & S390_OPERAND_GPR)
 	info->fprintf_func (info->stream, "%c%%r%u", separator, val.u);
       else if (flags & S390_OPERAND_FPR)
diff --git a/opcodes/s390-mkopc.c b/opcodes/s390-mkopc.c
index 68c55a94992..0d4c9df777a 100644
--- a/opcodes/s390-mkopc.c
+++ b/opcodes/s390-mkopc.c
@@ -411,12 +411,16 @@ main (void)
 		&& (str[7] == 0 || str[7] == ',')) {
 	      flag_bits |= S390_INSTR_FLAG_OPTPARM;
 	      str += 7;
+	    } else if (strncmp (str, "optparm2", 8) == 0
+		       && (str[8] == 0 || str[8] == ',')) {
+	      flag_bits |= S390_INSTR_FLAG_OPTPARM2;
+	      str += 8;
 	    } else if (strncmp (str, "htm", 3) == 0
-		&& (str[3] == 0 || str[3] == ',')) {
+		       && (str[3] == 0 || str[3] == ',')) {
 	      flag_bits |= S390_INSTR_FLAG_HTM;
 	      str += 3;
 	    } else if (strncmp (str, "vx", 2) == 0
-		&& (str[2] == 0 || str[2] == ',')) {
+		       && (str[2] == 0 || str[2] == ',')) {
 	      flag_bits |= S390_INSTR_FLAG_VX;
 	      str += 2;
 	    } else {