X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gdb%2Fax-general.c;h=360e91bf31857fd6999584d1e878707707ee7f29;hb=f6efe3f842e72e23ec6d8a57d683ce90d2e89785;hp=34ec3b3071ed42273b35ccbb9e69d5f9da7ba187;hpb=abd8680d6efd97e7ba848a6392ee3ad72be18cd0;p=deliverable%2Fbinutils-gdb.git

diff --git a/gdb/ax-general.c b/gdb/ax-general.c
index 34ec3b3071..360e91bf31 100644
--- a/gdb/ax-general.c
+++ b/gdb/ax-general.c
@@ -1,11 +1,11 @@
 /* Functions for manipulating expressions designed to be executed on the agent
-   Copyright 1998, 2000 Free Software Foundation, Inc.
+   Copyright (C) 1998-2018 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2 of the License, or
+   the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
@@ -14,9 +14,7 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software
-   Foundation, Inc., 59 Temple Place - Suite 330,
-   Boston, MA 02111-1307, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 /* Despite what the above comment says about this file being part of
    GDB, we would like to keep these functions free of GDB
@@ -27,55 +25,53 @@
 #include "ax.h"
 
 #include "value.h"
+#include "user-regs.h"
 
-static void grow_expr PARAMS ((struct agent_expr * x, int n));
+static void grow_expr (struct agent_expr *x, int n);
 
-static void append_const PARAMS ((struct agent_expr * x, LONGEST val, int n));
+static void append_const (struct agent_expr *x, LONGEST val, int n);
 
-static LONGEST read_const PARAMS ((struct agent_expr * x, int o, int n));
+static LONGEST read_const (struct agent_expr *x, int o, int n);
 
-static void generic_ext PARAMS ((struct agent_expr * x, enum agent_op op, int n));
+static void generic_ext (struct agent_expr *x, enum agent_op op, int n);
 
 /* Functions for building expressions.  */
 
-/* Allocate a new, empty agent expression.  */
-struct agent_expr *
-new_agent_expr (scope)
-     CORE_ADDR scope;
+agent_expr::agent_expr (struct gdbarch *gdbarch, CORE_ADDR scope)
 {
-  struct agent_expr *x = xmalloc (sizeof (*x));
-  x->len = 0;
-  x->size = 1;			/* Change this to a larger value once
+  this->len = 0;
+  this->size = 1;		/* Change this to a larger value once
 				   reallocation code is tested.  */
-  x->buf = xmalloc (x->size);
-  x->scope = scope;
+  this->buf = (unsigned char *) xmalloc (this->size);
 
-  return x;
+  this->gdbarch = gdbarch;
+  this->scope = scope;
+
+  /* Bit vector for registers used.  */
+  this->reg_mask_len = 1;
+  this->reg_mask = XCNEWVEC (unsigned char, this->reg_mask_len);
+
+  this->tracing = 0;
+  this->trace_string = 0;
 }
 
-/* Free a agent expression.  */
-void
-free_agent_expr (x)
-     struct agent_expr *x;
+agent_expr::~agent_expr ()
 {
-  free (x->buf);
-  free (x);
+  xfree (this->buf);
+  xfree (this->reg_mask);
 }
 
-
 /* Make sure that X has room for at least N more bytes.  This doesn't
    affect the length, just the allocated size.  */
 static void
-grow_expr (x, n)
-     struct agent_expr *x;
-     int n;
+grow_expr (struct agent_expr *x, int n)
 {
   if (x->len + n > x->size)
     {
       x->size *= 2;
       if (x->size < x->len + n)
 	x->size = x->len + n + 10;
-      x->buf = xrealloc (x->buf, x->size);
+      x->buf = (unsigned char *) xrealloc (x->buf, x->size);
     }
 }
 
@@ -83,10 +79,7 @@ grow_expr (x, n)
 /* Append the low N bytes of VAL as an N-byte integer to the
    expression X, in big-endian order.  */
 static void
-append_const (x, val, n)
-     struct agent_expr *x;
-     LONGEST val;
-     int n;
+append_const (struct agent_expr *x, LONGEST val, int n)
 {
   int i;
 
@@ -103,16 +96,14 @@ append_const (x, val, n)
 /* Extract an N-byte big-endian unsigned integer from expression X at
    offset O.  */
 static LONGEST
-read_const (x, o, n)
-     struct agent_expr *x;
-     int o, n;
+read_const (struct agent_expr *x, int o, int n)
 {
   int i;
   LONGEST accum = 0;
 
   /* Make sure we're not reading off the end of the expression.  */
   if (o + n > x->len)
-    error ("GDB bug: ax-general.c (read_const): incomplete constant");
+    error (_("GDB bug: ax-general.c (read_const): incomplete constant"));
 
   for (i = 0; i < n; i++)
     accum = (accum << 8) | x->buf[o + i];
@@ -120,32 +111,47 @@ read_const (x, o, n)
   return accum;
 }
 
+/* See ax.h.  */
 
-/* Append a simple operator OP to EXPR.  */
 void
-ax_simple (x, op)
-     struct agent_expr *x;
-     enum agent_op op;
+ax_raw_byte (struct agent_expr *x, gdb_byte byte)
 {
   grow_expr (x, 1);
-  x->buf[x->len++] = op;
+  x->buf[x->len++] = byte;
+}
+
+/* Append a simple operator OP to EXPR.  */
+void
+ax_simple (struct agent_expr *x, enum agent_op op)
+{
+  ax_raw_byte (x, op);
+}
+
+/* Append a pick operator to EXPR.  DEPTH is the stack item to pick,
+   with 0 being top of stack.  */
+
+void
+ax_pick (struct agent_expr *x, int depth)
+{
+  if (depth < 0 || depth > 255)
+    error (_("GDB bug: ax-general.c (ax_pick): stack depth out of range"));
+  ax_simple (x, aop_pick);
+  append_const (x, 1, depth);
 }
 
 
 /* Append a sign-extension or zero-extension instruction to EXPR, to
    extend an N-bit value.  */
 static void
-generic_ext (x, op, n)
-     struct agent_expr *x;
-     enum agent_op op;
-     int n;
+generic_ext (struct agent_expr *x, enum agent_op op, int n)
 {
   /* N must fit in a byte.  */
   if (n < 0 || n > 255)
-    error ("GDB bug: ax-general.c (generic_ext): bit count out of range");
+    error (_("GDB bug: ax-general.c (generic_ext): bit count out of range"));
   /* That had better be enough range.  */
   if (sizeof (LONGEST) * 8 > 255)
-    error ("GDB bug: ax-general.c (generic_ext): opcode has inadequate range");
+    error (_("GDB bug: ax-general.c (generic_ext): "
+	     "opcode has inadequate range"));
 
   grow_expr (x, 2);
   x->buf[x->len++] = op;
@@ -155,9 +161,7 @@ generic_ext (x, op, n)
 
 /* Append a sign-extension instruction to EXPR, to extend an N-bit value.  */
 void
-ax_ext (x, n)
-     struct agent_expr *x;
-     int n;
+ax_ext (struct agent_expr *x, int n)
 {
   generic_ext (x, aop_ext, n);
 }
@@ -165,9 +169,7 @@ ax_ext (x, n)
 
 /* Append a zero-extension instruction to EXPR, to extend an N-bit value.  */
 void
-ax_zero_ext (x, n)
-     struct agent_expr *x;
-     int n;
+ax_zero_ext (struct agent_expr *x, int n)
 {
   generic_ext (x, aop_zero_ext, n);
 }
@@ -175,13 +177,12 @@ ax_zero_ext (x, n)
 
 /* Append a trace_quick instruction to EXPR, to record N bytes.  */
 void
-ax_trace_quick (x, n)
-     struct agent_expr *x;
-     int n;
+ax_trace_quick (struct agent_expr *x, int n)
 {
   /* N must fit in a byte.  */
   if (n < 0 || n > 255)
-    error ("GDB bug: ax-general.c (ax_trace_quick): size out of range for trace_quick");
+    error (_("GDB bug: ax-general.c (ax_trace_quick): "
+	     "size out of range for trace_quick"));
 
   grow_expr (x, 2);
   x->buf[x->len++] = aop_trace_quick;
@@ -196,9 +197,7 @@ ax_trace_quick (x, n)
    can backpatch it once we do know the target offset.  Use ax_label
    to do the backpatching.  */
 int
-ax_goto (x, op)
-     struct agent_expr *x;
-     enum agent_op op;
+ax_goto (struct agent_expr *x, enum agent_op op)
 {
   grow_expr (x, 3);
   x->buf[x->len + 0] = op;
@@ -213,15 +212,12 @@ ax_goto (x, op)
    ax_label (EXPR, PATCH, TARGET)
    to patch TARGET into the ax_goto instruction.  */
 void
-ax_label (x, patch, target)
-     struct agent_expr *x;
-     int patch;
-     int target;
+ax_label (struct agent_expr *x, int patch, int target)
 {
   /* Make sure the value is in range.  Don't accept 0xffff as an
      offset; that's our magic sentinel value for unpatched branches.  */
   if (target < 0 || target >= 0xffff)
-    error ("GDB bug: ax-general.c (ax_label): label target out of range");
+    error (_("GDB bug: ax-general.c (ax_label): label target out of range"));
 
   x->buf[patch] = (target >> 8) & 0xff;
   x->buf[patch + 1] = target & 0xff;
@@ -230,9 +226,7 @@ ax_label (x, patch, target)
 
 /* Assemble code to push a constant on the stack.  */
 void
-ax_const_l (x, l)
-     struct agent_expr *x;
-     LONGEST l;
+ax_const_l (struct agent_expr *x, LONGEST l)
 {
   static enum agent_op ops[]
   =
@@ -245,10 +239,14 @@ ax_const_l (x, l)
      signed or unsigned; we always reproduce the value exactly, and
      use the shortest representation.  */
   for (op = 0, size = 8; size < 64; size *= 2, op++)
-    if (-((LONGEST) 1 << size) <= l && l < ((LONGEST) 1 << size))
-      break;
+    {
+      LONGEST lim = ((LONGEST) 1) << (size - 1);
+
+      if (-lim <= l && l <= lim - 1)
+        break;
+    }
 
-  /* Emit the right opcode... */
+  /* Emit the right opcode...  */
   ax_simple (x, ops[op]);
 
   /* Emit the low SIZE bytes as an unsigned number.  We know that
@@ -262,31 +260,88 @@ ax_const_l (x, l)
 
 
 void
-ax_const_d (x, d)
-     struct agent_expr *x;
-     LONGEST d;
+ax_const_d (struct agent_expr *x, LONGEST d)
 {
   /* FIXME: floating-point support not present yet.  */
-  error ("GDB bug: ax-general.c (ax_const_d): floating point not supported yet");
+  error (_("GDB bug: ax-general.c (ax_const_d): "
+	   "floating point not supported yet"));
 }
 
 
 /* Assemble code to push the value of register number REG on the
    stack.  */
 void
-ax_reg (x, reg)
-     struct agent_expr *x;
-     int reg;
+ax_reg (struct agent_expr *x, int reg)
 {
-  /* Make sure the register number is in range.  */
-  if (reg < 0 || reg > 0xffff)
-    error ("GDB bug: ax-general.c (ax_reg): register number out of range");
+  if (reg >= gdbarch_num_regs (x->gdbarch))
+    {
+      /* This is a pseudo-register.  */
+      if (!gdbarch_ax_pseudo_register_push_stack_p (x->gdbarch))
+	error (_("'%s' is a pseudo-register; "
+		 "GDB cannot yet trace its contents."),
+	       user_reg_map_regnum_to_name (x->gdbarch, reg));
+      if (gdbarch_ax_pseudo_register_push_stack (x->gdbarch, x, reg))
+	error (_("Trace '%s' failed."),
+	       user_reg_map_regnum_to_name (x->gdbarch, reg));
+    }
+  else
+    {
+      /* Get the remote register number.  */
+      reg = gdbarch_remote_register_number (x->gdbarch, reg);
+
+      /* Make sure the register number is in range.  */
+      if (reg < 0 || reg > 0xffff)
+        error (_("GDB bug: ax-general.c (ax_reg): "
+		 "register number out of range"));
+      grow_expr (x, 3);
+      x->buf[x->len] = aop_reg;
+      x->buf[x->len + 1] = (reg >> 8) & 0xff;
+      x->buf[x->len + 2] = (reg) & 0xff;
+      x->len += 3;
+    }
+}
+
+/* Assemble code to operate on a trace state variable.  */
+
+void
+ax_tsv (struct agent_expr *x, enum agent_op op, int num)
+{
+  /* Make sure the tsv number is in range.  */
+  if (num < 0 || num > 0xffff)
+    internal_error (__FILE__, __LINE__, 
+		    _("ax-general.c (ax_tsv): variable "
+		      "number is %d, out of range"), num);
+
   grow_expr (x, 3);
-  x->buf[x->len] = aop_reg;
-  x->buf[x->len + 1] = (reg >> 8) & 0xff;
-  x->buf[x->len + 2] = (reg) & 0xff;
+  x->buf[x->len] = op;
+  x->buf[x->len + 1] = (num >> 8) & 0xff;
+  x->buf[x->len + 2] = (num) & 0xff;
   x->len += 3;
 }
+
+/* Append a string to the expression.  Note that the string is going
+   into the bytecodes directly, not on the stack.  As a precaution,
+   include both length as prefix, and terminate with a NUL.  (The NUL
+   is counted in the length.)  */
+
+void
+ax_string (struct agent_expr *x, const char *str, int slen)
+{
+  int i;
+
+  /* Make sure the string length is reasonable.  */
+  if (slen < 0 || slen > 0xffff)
+    internal_error (__FILE__, __LINE__, 
+		    _("ax-general.c (ax_string): string "
+		      "length is %d, out of allowed range"), slen);
+
+  grow_expr (x, 2 + slen + 1);
+  x->buf[x->len++] = ((slen + 1) >> 8) & 0xff;
+  x->buf[x->len++] = (slen + 1) & 0xff;
+  for (i = 0; i < slen; ++i)
+    x->buf[x->len++] = str[i];
+  x->buf[x->len++] = '\0';
+}
 
 
 
@@ -295,87 +350,46 @@ ax_reg (x, reg)
 
 struct aop_map aop_map[] =
 {
-  {0, 0, 0, 0, 0},
-  {"float", 0, 0, 0, 0},	/* 0x01 */
-  {"add", 0, 0, 2, 1},		/* 0x02 */
-  {"sub", 0, 0, 2, 1},		/* 0x03 */
-  {"mul", 0, 0, 2, 1},		/* 0x04 */
-  {"div_signed", 0, 0, 2, 1},	/* 0x05 */
-  {"div_unsigned", 0, 0, 2, 1},	/* 0x06 */
-  {"rem_signed", 0, 0, 2, 1},	/* 0x07 */
-  {"rem_unsigned", 0, 0, 2, 1},	/* 0x08 */
-  {"lsh", 0, 0, 2, 1},		/* 0x09 */
-  {"rsh_signed", 0, 0, 2, 1},	/* 0x0a */
-  {"rsh_unsigned", 0, 0, 2, 1},	/* 0x0b */
-  {"trace", 0, 0, 2, 0},	/* 0x0c */
-  {"trace_quick", 1, 0, 1, 1},	/* 0x0d */
-  {"log_not", 0, 0, 1, 1},	/* 0x0e */
-  {"bit_and", 0, 0, 2, 1},	/* 0x0f */
-  {"bit_or", 0, 0, 2, 1},	/* 0x10 */
-  {"bit_xor", 0, 0, 2, 1},	/* 0x11 */
-  {"bit_not", 0, 0, 1, 1},	/* 0x12 */
-  {"equal", 0, 0, 2, 1},	/* 0x13 */
-  {"less_signed", 0, 0, 2, 1},	/* 0x14 */
-  {"less_unsigned", 0, 0, 2, 1},	/* 0x15 */
-  {"ext", 1, 0, 1, 1},		/* 0x16 */
-  {"ref8", 0, 8, 1, 1},		/* 0x17 */
-  {"ref16", 0, 16, 1, 1},	/* 0x18 */
-  {"ref32", 0, 32, 1, 1},	/* 0x19 */
-  {"ref64", 0, 64, 1, 1},	/* 0x1a */
-  {"ref_float", 0, 0, 1, 1},	/* 0x1b */
-  {"ref_double", 0, 0, 1, 1},	/* 0x1c */
-  {"ref_long_double", 0, 0, 1, 1},	/* 0x1d */
-  {"l_to_d", 0, 0, 1, 1},	/* 0x1e */
-  {"d_to_l", 0, 0, 1, 1},	/* 0x1f */
-  {"if_goto", 2, 0, 1, 0},	/* 0x20 */
-  {"goto", 2, 0, 0, 0},		/* 0x21 */
-  {"const8", 1, 8, 0, 1},	/* 0x22 */
-  {"const16", 2, 16, 0, 1},	/* 0x23 */
-  {"const32", 4, 32, 0, 1},	/* 0x24 */
-  {"const64", 8, 64, 0, 1},	/* 0x25 */
-  {"reg", 2, 0, 0, 1},		/* 0x26 */
-  {"end", 0, 0, 0, 0},		/* 0x27 */
-  {"dup", 0, 0, 1, 2},		/* 0x28 */
-  {"pop", 0, 0, 1, 0},		/* 0x29 */
-  {"zero_ext", 1, 0, 1, 1},	/* 0x2a */
-  {"swap", 0, 0, 2, 2},		/* 0x2b */
-  {0, 0, 0, 0, 0},		/* 0x2c */
-  {0, 0, 0, 0, 0},		/* 0x2d */
-  {0, 0, 0, 0, 0},		/* 0x2e */
-  {0, 0, 0, 0, 0},		/* 0x2f */
-  {"trace16", 2, 0, 1, 1},	/* 0x30 */
+  {0, 0, 0, 0, 0}
+#define DEFOP(NAME, SIZE, DATA_SIZE, CONSUMED, PRODUCED, VALUE) \
+  , { # NAME, SIZE, DATA_SIZE, CONSUMED, PRODUCED }
+#include "ax.def"
+#undef DEFOP
 };
 
 
 /* Disassemble the expression EXPR, writing to F.  */
 void
-ax_print (f, x)
-     struct ui_file *f;
-     struct agent_expr *x;
+ax_print (struct ui_file *f, struct agent_expr *x)
 {
   int i;
-  int is_float = 0;
+
+  fprintf_filtered (f, _("Scope: %s\n"), paddress (x->gdbarch, x->scope));
+  fprintf_filtered (f, _("Reg mask:"));
+  for (i = 0; i < x->reg_mask_len; ++i)
+    fprintf_filtered (f, _(" %02x"), x->reg_mask[i]);
+  fprintf_filtered (f, _("\n"));
 
   /* Check the size of the name array against the number of entries in
      the enum, to catch additions that people didn't sync.  */
   if ((sizeof (aop_map) / sizeof (aop_map[0]))
       != aop_last)
-    error ("GDB bug: ax-general.c (ax_print): opcode map out of sync");
+    error (_("GDB bug: ax-general.c (ax_print): opcode map out of sync"));
 
   for (i = 0; i < x->len;)
     {
-      enum agent_op op = x->buf[i];
+      enum agent_op op = (enum agent_op) x->buf[i];
 
       if (op >= (sizeof (aop_map) / sizeof (aop_map[0]))
 	  || !aop_map[op].name)
 	{
-	  fprintf_filtered (f, "%3d  <bad opcode %02x>\n", i, op);
+	  fprintf_filtered (f, _("%3d  <bad opcode %02x>\n"), i, op);
 	  i++;
 	  continue;
 	}
       if (i + 1 + aop_map[op].op_size > x->len)
 	{
-	  fprintf_filtered (f, "%3d  <incomplete opcode %s>\n",
+	  fprintf_filtered (f, _("%3d  <incomplete opcode %s>\n"),
 			    i, aop_map[op].name);
 	  break;
 	}
@@ -388,37 +402,83 @@ ax_print (f, x)
 	  print_longest (f, 'd', 0,
 			 read_const (x, i + 1, aop_map[op].op_size));
 	}
+      /* Handle the complicated printf arguments specially.  */
+      else if (op == aop_printf)
+	{
+	  int slen, nargs;
+
+	  i++;
+	  nargs = x->buf[i++];
+	  slen = x->buf[i++];
+	  slen = slen * 256 + x->buf[i++];
+	  fprintf_filtered (f, _(" \"%s\", %d args"),
+			    &(x->buf[i]), nargs);
+	  i += slen - 1;
+	}
       fprintf_filtered (f, "\n");
       i += 1 + aop_map[op].op_size;
-
-      is_float = (op == aop_float);
     }
 }
 
+/* Add register REG to the register mask for expression AX.  */
+void
+ax_reg_mask (struct agent_expr *ax, int reg)
+{
+  if (reg >= gdbarch_num_regs (ax->gdbarch))
+    {
+      /* This is a pseudo-register.  */
+      if (!gdbarch_ax_pseudo_register_collect_p (ax->gdbarch))
+	error (_("'%s' is a pseudo-register; "
+		 "GDB cannot yet trace its contents."),
+	       user_reg_map_regnum_to_name (ax->gdbarch, reg));
+      if (gdbarch_ax_pseudo_register_collect (ax->gdbarch, ax, reg))
+	error (_("Trace '%s' failed."),
+	       user_reg_map_regnum_to_name (ax->gdbarch, reg));
+    }
+  else
+    {
+      int byte;
+
+      /* Get the remote register number.  */
+      reg = gdbarch_remote_register_number (ax->gdbarch, reg);
+      byte = reg / 8;
+
+      /* Grow the bit mask if necessary.  */
+      if (byte >= ax->reg_mask_len)
+        {
+          /* It's not appropriate to double here.  This isn't a
+	     string buffer.  */
+          int new_len = byte + 1;
+          unsigned char *new_reg_mask
+	    = XRESIZEVEC (unsigned char, ax->reg_mask, new_len);
+
+          memset (new_reg_mask + ax->reg_mask_len, 0,
+	          (new_len - ax->reg_mask_len) * sizeof (ax->reg_mask[0]));
+          ax->reg_mask_len = new_len;
+          ax->reg_mask = new_reg_mask;
+        }
+
+      ax->reg_mask[byte] |= 1 << (reg % 8);
+    }
+}
 
-/* Given an agent expression AX, fill in an agent_reqs structure REQS
-   describing it.  */
+/* Given an agent expression AX, fill in requirements and other descriptive
+   bits.  */
 void
-ax_reqs (ax, reqs)
-     struct agent_expr *ax;
-     struct agent_reqs *reqs;
+ax_reqs (struct agent_expr *ax)
 {
   int i;
   int height;
 
-  /* Bit vector for registers used.  */
-  int reg_mask_len = 1;
-  unsigned char *reg_mask = xmalloc (reg_mask_len * sizeof (reg_mask[0]));
-
-  /* Jump target table.  targets[i] is non-zero iff there is a jump to
-     offset i.  */
+  /* Jump target table.  targets[i] is non-zero iff we have found a
+     jump to offset i.  */
   char *targets = (char *) alloca (ax->len * sizeof (targets[0]));
 
-  /* Instruction boundary table.  boundary[i] is non-zero iff an
-     instruction starts at offset i.  */
+  /* Instruction boundary table.  boundary[i] is non-zero iff our scan
+     has reached an instruction starting at offset i.  */
   char *boundary = (char *) alloca (ax->len * sizeof (boundary[0]));
 
-  /* Stack height record.  iff either targets[i] or boundary[i] is
+  /* Stack height record.  If either targets[i] or boundary[i] is
      non-zero, heights[i] is the height the stack should have before
      executing the bytecode at that point.  */
   int *heights = (int *) alloca (ax->len * sizeof (heights[0]));
@@ -426,20 +486,18 @@ ax_reqs (ax, reqs)
   /* Pointer to a description of the present op.  */
   struct aop_map *op;
 
-  memset (reg_mask, 0, reg_mask_len * sizeof (reg_mask[0]));
   memset (targets, 0, ax->len * sizeof (targets[0]));
   memset (boundary, 0, ax->len * sizeof (boundary[0]));
 
-  reqs->max_height = reqs->min_height = height = 0;
-  reqs->flaw = agent_flaw_none;
-  reqs->max_data_size = 0;
+  ax->max_height = ax->min_height = height = 0;
+  ax->flaw = agent_flaw_none;
+  ax->max_data_size = 0;
 
   for (i = 0; i < ax->len; i += 1 + op->op_size)
     {
       if (ax->buf[i] > (sizeof (aop_map) / sizeof (aop_map[0])))
 	{
-	  reqs->flaw = agent_flaw_bad_instruction;
-	  free (reg_mask);
+	  ax->flaw = agent_flaw_bad_instruction;
 	  return;
 	}
 
@@ -447,24 +505,22 @@ ax_reqs (ax, reqs)
 
       if (!op->name)
 	{
-	  reqs->flaw = agent_flaw_bad_instruction;
-	  free (reg_mask);
+	  ax->flaw = agent_flaw_bad_instruction;
 	  return;
 	}
 
       if (i + 1 + op->op_size > ax->len)
 	{
-	  reqs->flaw = agent_flaw_incomplete_instruction;
-	  free (reg_mask);
+	  ax->flaw = agent_flaw_incomplete_instruction;
 	  return;
 	}
 
-      /* If this instruction is a jump target, does the current stack
-         height match the stack height at the jump source?  */
+      /* If this instruction is a forward jump target, does the
+         current stack height match the stack height at the jump
+         source?  */
       if (targets[i] && (heights[i] != height))
 	{
-	  reqs->flaw = agent_flaw_height_mismatch;
-	  free (reg_mask);
+	  ax->flaw = agent_flaw_height_mismatch;
 	  return;
 	}
 
@@ -472,14 +528,14 @@ ax_reqs (ax, reqs)
       heights[i] = height;
 
       height -= op->consumed;
-      if (height < reqs->min_height)
-	reqs->min_height = height;
+      if (height < ax->min_height)
+	ax->min_height = height;
       height += op->produced;
-      if (height > reqs->max_height)
-	reqs->max_height = height;
+      if (height > ax->max_height)
+	ax->max_height = height;
 
-      if (op->data_size > reqs->max_data_size)
-	reqs->max_data_size = op->data_size;
+      if (op->data_size > ax->max_data_size)
+	ax->max_data_size = op->data_size;
 
       /* For jump instructions, check that the target is a valid
          offset.  If it is, record the fact that that location is a
@@ -490,25 +546,24 @@ ax_reqs (ax, reqs)
 	  int target = read_const (ax, i + 1, 2);
 	  if (target < 0 || target >= ax->len)
 	    {
-	      reqs->flaw = agent_flaw_bad_jump;
-	      free (reg_mask);
+	      ax->flaw = agent_flaw_bad_jump;
 	      return;
 	    }
-	  /* Have we already found other jumps to the same location?  */
-	  else if (targets[target])
+
+	  /* Do we have any information about what the stack height
+             should be at the target?  */
+	  if (targets[target] || boundary[target])
 	    {
-	      if (heights[i] != height)
+	      if (heights[target] != height)
 		{
-		  reqs->flaw = agent_flaw_height_mismatch;
-		  free (reg_mask);
+		  ax->flaw = agent_flaw_height_mismatch;
 		  return;
 		}
 	    }
-	  else
-	    {
-	      targets[target] = 1;
-	      heights[target] = height;
-	    }
+
+          /* Record the target, along with the stack height we expect.  */
+          targets[target] = 1;
+          heights[target] = height;
 	}
 
       /* For unconditional jumps with a successor, check that the
@@ -518,8 +573,7 @@ ax_reqs (ax, reqs)
 	{
 	  if (!targets[i + 3])
 	    {
-	      reqs->flaw = agent_flaw_hole;
-	      free (reg_mask);
+	      ax->flaw = agent_flaw_hole;
 	      return;
 	    }
 
@@ -530,22 +584,8 @@ ax_reqs (ax, reqs)
       if (aop_reg == op - aop_map)
 	{
 	  int reg = read_const (ax, i + 1, 2);
-	  int byte = reg / 8;
-
-	  /* Grow the bit mask if necessary.  */
-	  if (byte >= reg_mask_len)
-	    {
-	      /* It's not appropriate to double here.  This isn't a
-	         string buffer.  */
-	      int new_len = byte + 1;
-	      reg_mask = xrealloc (reg_mask,
-				   new_len * sizeof (reg_mask[0]));
-	      memset (reg_mask + reg_mask_len, 0,
-		      (new_len - reg_mask_len) * sizeof (reg_mask[0]));
-	      reg_mask_len = new_len;
-	    }
 
-	  reg_mask[byte] |= 1 << (reg % 8);
+	  ax_reg_mask (ax, reg);
 	}
     }
 
@@ -553,12 +593,9 @@ ax_reqs (ax, reqs)
   for (i = 0; i < ax->len; i++)
     if (targets[i] && !boundary[i])
       {
-	reqs->flaw = agent_flaw_bad_jump;
-	free (reg_mask);
+	ax->flaw = agent_flaw_bad_jump;
 	return;
       }
 
-  reqs->final_height = height;
-  reqs->reg_mask_len = reg_mask_len;
-  reqs->reg_mask = reg_mask;
+  ax->final_height = height;
 }