Re: H8300 use of uninitialised value

This patch also had some problems.  Calculation of maxlen was wrong,
and the insn arg loop needed rearranging to work with a correct length.

	* disassemble.h (opcodes_assert): Declare.
	(OPCODES_ASSERT): Define.
	* disassemble.c: Don't include assert.h.  Include opintl.h.
	(opcodes_assert): New function.
	* h8300-dis.c (bfd_h8_disassemble_init): Use OPCODES_ASSERT.
	(bfd_h8_disassemble): Reduce size of data array.  Correctly
	calculate maxlen.  Omit insn decoding when insn length exceeds
	maxlen.  Exit from nibble loop when looking for E, before
	accessing next data byte.  Move processing of E outside loop.
	Replace tests of maxlen in loop with assertions.

1 files changed, 124 insertions, 125 deletions

diff --git a/opcodes/h8300-dis.c b/opcodes/h8300-dis.c
index f5e00c40c1b..f56ad86771d 100644
--- a/opcodes/h8300-dis.c
+++ b/opcodes/h8300-dis.c
@@ -29,7 +29,7 @@
 
 struct h8_instruction
 {
-  int length;
+  unsigned int length;
   const struct h8_opcode *opcode;
 };
 
@@ -56,13 +56,7 @@ bfd_h8_disassemble_init (void)
 	 that the count is the same as the length.  */
       for (i = 0; p->data.nib[i] != (op_type) E; i++)
 	;
-
-      if (i & 1)
-	{
-	  /* xgettext:c-format */
-	  opcodes_error_handler (_("internal error, h8_disassemble_init"));
-	  abort ();
-	}
+      OPCODES_ASSERT (!(i & 1));
 
       pi->length = i / 2;
       pi->opcode = p;
@@ -328,7 +322,7 @@ bfd_h8_disassemble (bfd_vma addr, disassemble_info *info, int mach)
   char const **pregnames = mach != 0 ? lregnames : wregnames;
   int status;
   unsigned int maxlen;
-  unsigned char data[MAX_CODE_NIBBLES];
+  unsigned char data[MAX_CODE_NIBBLES / 2];
   void *stream = info->stream;
   fprintf_ftype outfn = info->fprintf_func;
 
@@ -345,22 +339,34 @@ bfd_h8_disassemble (bfd_vma addr, disassemble_info *info, int mach)
       return -1;
     }
 
-  for (maxlen = 2; status == 0 && maxlen < sizeof (data) / 2; maxlen += 2)
-    status = info->read_memory_func (addr + maxlen, data + maxlen, 2, info);
+  for (maxlen = 2; maxlen < sizeof (data); maxlen += 2)
+    {
+      status = info->read_memory_func (addr + maxlen, data + maxlen, 2, info);
+      if (status != 0)
+	break;
+    }
 
   /* Find the exact opcode/arg combo.  */
   for (qi = h8_instructions; qi->opcode->name; qi++)
     {
-      const struct h8_opcode *q = qi->opcode;
-      const op_type *nib = q->data.nib;
-      unsigned int len = 0;
-
-      while (len / 2 < maxlen)
+      const struct h8_opcode *q;
+      const op_type *nib;
+      unsigned int len;
+      op_type looking_for;
+
+      if (qi->length > maxlen)
+	continue;
+
+      q = qi->opcode;
+      nib = q->data.nib;
+      len = 0;
+      while ((looking_for = *nib) != (op_type) E)
 	{
-	  op_type looking_for = *nib;
-	  int thisnib = data[len / 2];
+	  int thisnib;
 	  int opnr;
 
+	  OPCODES_ASSERT (len / 2 < maxlen);
+	  thisnib = data[len / 2];
 	  thisnib = (len & 1) ? (thisnib & 0xf) : ((thisnib / 16) & 0xf);
 	  opnr = ((looking_for & OP3) == OP3 ? 2
 		  : (looking_for & DST) == DST ? 1 : 0);
@@ -476,8 +482,7 @@ bfd_h8_disassemble (bfd_vma addr, disassemble_info *info, int mach)
 		      extra = 0;
 		      break;
 		    }
-		  if (len / 2 + extra >= maxlen)
-		    break;
+		  OPCODES_ASSERT (len / 2 + extra < maxlen);
 		  extract_immediate (stream, looking_for, thisnib,
 				     data + len / 2, cst + opnr,
 				     cstlen + opnr, q);
@@ -532,8 +537,7 @@ bfd_h8_disassemble (bfd_vma addr, disassemble_info *info, int mach)
 	      else if ((looking_for & SIZE) == L_16
 		       || (looking_for & SIZE) == L_16U)
 		{
-		  if (len / 2 + 1 >= maxlen)
-		    break;
+		  OPCODES_ASSERT (len / 2 + 1 < maxlen);
 		  cst[opnr] = (data[len / 2]) * 256 + data[(len + 2) / 2];
 		  cstlen[opnr] = 16;
 		}
@@ -549,8 +553,7 @@ bfd_h8_disassemble (bfd_vma addr, disassemble_info *info, int mach)
 		{
 		  unsigned int i = len / 2;
 
-		  if (i + 3 >= maxlen)
-		    break;
+		  OPCODES_ASSERT (i + 3 < maxlen);
 		  cst[opnr] = (((unsigned) data[i] << 24)
 			       | (data[i + 1] << 16)
 			       | (data[i + 2] << 8)
@@ -562,8 +565,7 @@ bfd_h8_disassemble (bfd_vma addr, disassemble_info *info, int mach)
 		{
 		  unsigned int i = len / 2;
 
-		  if (i + 2 >= maxlen)
-		    break;
+		  OPCODES_ASSERT (i + 2 < maxlen);
 		  cst[opnr] =
 		    (data[i] << 16) | (data[i + 1] << 8) | (data[i + 2]);
 		  cstlen[opnr] = 24;
@@ -610,105 +612,6 @@ bfd_h8_disassemble (bfd_vma addr, disassemble_info *info, int mach)
 		{
 		  cst[opnr] = (thisnib == 3);
 		}
-	      else if (looking_for == (op_type) E)
-		{
-		  outfn (stream, "%s\t", q->name);
-
-		  /* Gross.  Disgusting.  */
-		  if (strcmp (q->name, "ldm.l") == 0)
-		    {
-		      int count, high;
-
-		      count = (data[1] / 16) & 0x3;
-		      high = regno[1];
-
-		      outfn (stream, "@sp+,er%d-er%d", high - count, high);
-		      return qi->length;
-		    }
-
-		  if (strcmp (q->name, "stm.l") == 0)
-		    {
-		      int count, low;
-
-		      count = (data[1] / 16) & 0x3;
-		      low = regno[0];
-
-		      outfn (stream, "er%d-er%d,@-sp", low, low + count);
-		      return qi->length;
-		    }
-		  if (strcmp (q->name, "rte/l") == 0
-		      || strcmp (q->name, "rts/l") == 0)
-		    {
-		      if (regno[0] == 0)
-			outfn (stream, "er%d", regno[1]);
-		      else
-			outfn (stream, "er%d-er%d", regno[1] - regno[0],
-			       regno[1]);
-		      return qi->length;
-		    }
-		  if (CONST_STRNEQ (q->name, "mova"))
-		    {
-		      const op_type *args = q->args.nib;
-
-		      if (args[1] == (op_type) E)
-			{
-			  /* Short form.  */
-			  print_one_arg (info, addr, args[0], cst[0],
-					 cstlen[0], dispregno[0], regno[0],
-					 pregnames, qi->length);
-			  outfn (stream, ",er%d", dispregno[0]);
-			}
-		      else
-			{
-			  outfn (stream, "@(0x%x:%d,", cst[0], cstlen[0]);
-			  print_one_arg (info, addr, args[1], cst[1],
-					 cstlen[1], dispregno[1], regno[1],
-					 pregnames, qi->length);
-			  outfn (stream, ".%c),",
-				 (args[0] & MODE) == INDEXB ? 'b' : 'w');
-			  print_one_arg (info, addr, args[2], cst[2],
-					 cstlen[2], dispregno[2], regno[2],
-					 pregnames, qi->length);
-			}
-		      return qi->length;
-		    }
-		  /* Fill in the args.  */
-		  {
-		    const op_type *args = q->args.nib;
-		    int hadone = 0;
-		    int nargs;
-
-		    /* Special case handling for the adds and subs instructions
-		       since in H8 mode thay can only take the r0-r7 registers
-		       but in other (higher) modes they can take the er0-er7
-		       registers as well.  */
-		    if (strcmp (qi->opcode->name, "adds") == 0
-			|| strcmp (qi->opcode->name, "subs") == 0)
-		      {
-			outfn (stream, "#%d,%s", cst[0], pregnames[regno[1] & 0x7]);
-			return qi->length;
-		      }
-
-		    for (nargs = 0;
-			 nargs < 3 && args[nargs] != (op_type) E;
-			 nargs++)
-		      {
-			int x = args[nargs];
-
-			if (hadone)
-			  outfn (stream, ",");
-
-			print_one_arg (info, addr, x,
-				       cst[nargs], cstlen[nargs],
-				       dispregno[nargs], regno[nargs],
-				       pregnames, qi->length);
-
-			hadone = 1;
-		      }
-		  }
-
-		  return qi->length;
-		}
 	      else
 		/* xgettext:c-format */
 		outfn (stream, _("Don't understand 0x%x \n"), looking_for);
@@ -718,6 +621,102 @@ bfd_h8_disassemble (bfd_vma addr, disassemble_info *info, int mach)
 	  nib++;
 	}
 
+      outfn (stream, "%s\t", q->name);
+
+      /* Gross.  Disgusting.  */
+      if (strcmp (q->name, "ldm.l") == 0)
+	{
+	  int count, high;
+
+	  count = (data[1] / 16) & 0x3;
+	  high = regno[1];
+
+	  outfn (stream, "@sp+,er%d-er%d", high - count, high);
+	  return qi->length;
+	}
+
+      if (strcmp (q->name, "stm.l") == 0)
+	{
+	  int count, low;
+
+	  count = (data[1] / 16) & 0x3;
+	  low = regno[0];
+
+	  outfn (stream, "er%d-er%d,@-sp", low, low + count);
+	  return qi->length;
+	}
+      if (strcmp (q->name, "rte/l") == 0
+	  || strcmp (q->name, "rts/l") == 0)
+	{
+	  if (regno[0] == 0)
+	    outfn (stream, "er%d", regno[1]);
+	  else
+	    outfn (stream, "er%d-er%d", regno[1] - regno[0],
+		   regno[1]);
+	  return qi->length;
+	}
+      if (CONST_STRNEQ (q->name, "mova"))
+	{
+	  const op_type *args = q->args.nib;
+
+	  if (args[1] == (op_type) E)
+	    {
+	      /* Short form.  */
+	      print_one_arg (info, addr, args[0], cst[0],
+			     cstlen[0], dispregno[0], regno[0],
+			     pregnames, qi->length);
+	      outfn (stream, ",er%d", dispregno[0]);
+	    }
+	  else
+	    {
+	      outfn (stream, "@(0x%x:%d,", cst[0], cstlen[0]);
+	      print_one_arg (info, addr, args[1], cst[1],
+			     cstlen[1], dispregno[1], regno[1],
+			     pregnames, qi->length);
+	      outfn (stream, ".%c),",
+		     (args[0] & MODE) == INDEXB ? 'b' : 'w');
+	      print_one_arg (info, addr, args[2], cst[2],
+			     cstlen[2], dispregno[2], regno[2],
+			     pregnames, qi->length);
+	    }
+	  return qi->length;
+	}
+      /* Fill in the args.  */
+      {
+	const op_type *args = q->args.nib;
+	int hadone = 0;
+	int nargs;
+
+	/* Special case handling for the adds and subs instructions
+	   since in H8 mode thay can only take the r0-r7 registers
+	   but in other (higher) modes they can take the er0-er7
+	   registers as well.  */
+	if (strcmp (qi->opcode->name, "adds") == 0
+	    || strcmp (qi->opcode->name, "subs") == 0)
+	  {
+	    outfn (stream, "#%d,%s", cst[0], pregnames[regno[1] & 0x7]);
+	    return qi->length;
+	  }
+
+	for (nargs = 0;
+	     nargs < 3 && args[nargs] != (op_type) E;
+	     nargs++)
+	  {
+	    int x = args[nargs];
+
+	    if (hadone)
+	      outfn (stream, ",");
+
+	    print_one_arg (info, addr, x,
+			   cst[nargs], cstlen[nargs],
+			   dispregno[nargs], regno[nargs],
+			   pregnames, qi->length);
+
+	    hadone = 1;
+	  }
+      }
+      return qi->length;
+
     fail:
       ;
     }