2010-04-23 Stan Shebs <stan@codesourcery.com>

* ax.h (struct agent_expr): Merge in agent_reqs fields, add some
	comments.
	(struct agent_reqs): Remove.
	(ax_reg_mask): Declare.
	* ax-general.c (new_agent_expr): Add gdbarch argument, set new fields.
	(free_agent_expr): Free reg_mask.
	(ax_print): Add scope and register mask info.
	(ax_reqs): Remove agent_reqs argument, use agent expression
	fields, and move part of register mask computation to...
	(ax_reg_mask): New function.
	* ax-gdb.c (gen_trace_static_fields): Call it.
	(gen_traced_pop): Ditto.
	(is_nontrivial_conversion): Add dummy gdbarch to new_agent_expr.
	(gen_trace_for_var): Pass gdbarch to new_agent_expr.
	(gen_trace_for_expr): Ditto, and clear optimized_out flag.
	(gen_eval_for_expr): Ditto, and require an rvalue.
	(agent_command): Call ax_reqs.
	(agent_eval_command): Ditto.
	* tracepoint.c (report_agent_reqs_errors): Use agent expression fields.
	(validate_action_line): Ditto.
	(collect_symbol): Ditto.
	(encode_actions_1): Ditto.

gdb/ChangeLog

@@ -1,3 +1,28 @@
+2010-04-23  Stan Shebs  <stan@codesourcery.com>
+
+	* ax.h (struct agent_expr): Merge in agent_reqs fields, add some
+	comments.
+	(struct agent_reqs): Remove.
+	(ax_reg_mask): Declare.
+	* ax-general.c (new_agent_expr): Add gdbarch argument, set new fields.
+	(free_agent_expr): Free reg_mask.
+	(ax_print): Add scope and register mask info.
+	(ax_reqs): Remove agent_reqs argument, use agent expression
+	fields, and move part of register mask computation to...
+	(ax_reg_mask): New function.
+	* ax-gdb.c (gen_trace_static_fields): Call it.
+	(gen_traced_pop): Ditto.
+	(is_nontrivial_conversion): Add dummy gdbarch to new_agent_expr.
+	(gen_trace_for_var): Pass gdbarch to new_agent_expr.
+	(gen_trace_for_expr): Ditto, and clear optimized_out flag.
+	(gen_eval_for_expr): Ditto, and require an rvalue.
+	(agent_command): Call ax_reqs.
+	(agent_eval_command): Ditto.
+	* tracepoint.c (report_agent_reqs_errors): Use agent expression fields.
+	(validate_action_line): Ditto.
+	(collect_symbol): Ditto.
+	(encode_actions_1): Ditto.
+
 2010-04-23  Daniel Jacobowitz  <dan@codesourcery.com>
 	    Paul Pluzhnikov  <ppluzhnikov@google.com>
 	    Jan Kratochvil  <jan.kratochvil@redhat.com>

gdb/ax-gdb.c

@@ -363,10 +363,9 @@ gen_trace_static_fields (struct gdbarch *gdbarch,
 	      break;
 
 	    case axs_lvalue_register:
-	      /* We need to mention the register somewhere in the bytecode,
+	      /* We don't actually need the register's value to be pushed,
-		 so ax_reqs will pick it up and add it to the mask of
+		 just note that we need it to be collected.  */
-		 registers used.  */
+	      ax_reg_mask (ax, value.u.reg);
-	      ax_reg (ax, value.u.reg);
 
 	    default:
 	      break;
@@ -414,11 +413,11 @@ gen_traced_pop (struct gdbarch *gdbarch,
 	break;
 
       case axs_lvalue_register:
-	/* We need to mention the register somewhere in the bytecode,
+	/* We don't actually need the register's value to be on the
-	   so ax_reqs will pick it up and add it to the mask of
+	   stack, and the target will get heartburn if the register is
-	   registers used.  */
+	   larger than will fit in a stack, so just mark it for
-	ax_reg (ax, value->u.reg);
+	   collection and be done with it.  */
-	ax_simple (ax, aop_pop);
+	ax_reg_mask (ax, value->u.reg);
 	break;
       }
   else
@@ -898,7 +897,7 @@ gen_conversion (struct agent_expr *ax, struct type *from, struct type *to)
 static int
 is_nontrivial_conversion (struct type *from, struct type *to)
 {
-  struct agent_expr *ax = new_agent_expr (0);
+  struct agent_expr *ax = new_agent_expr (NULL, 0);
   int nontrivial;
 
   /* Actually generate the code, and see if anything came out.  At the
@@ -2324,7 +2323,7 @@ gen_trace_for_var (CORE_ADDR scope, struct gdbarch *gdbarch,
 		   struct symbol *var)
 {
   struct cleanup *old_chain = 0;
-  struct agent_expr *ax = new_agent_expr (scope);
+  struct agent_expr *ax = new_agent_expr (gdbarch, scope);
   struct axs_value value;
 
   old_chain = make_cleanup_free_agent_expr (ax);
@@ -2364,7 +2363,7 @@ struct agent_expr *
 gen_trace_for_expr (CORE_ADDR scope, struct expression *expr)
 {
   struct cleanup *old_chain = 0;
-  struct agent_expr *ax = new_agent_expr (scope);
+  struct agent_expr *ax = new_agent_expr (expr->gdbarch, scope);
   union exp_element *pc;
   struct axs_value value;
 
@@ -2372,6 +2371,7 @@ gen_trace_for_expr (CORE_ADDR scope, struct expression *expr)
 
   pc = expr->elts;
   trace_kludge = 1;
+  value.optimized_out = 0;
   gen_expr (expr, &pc, ax, &value);
 
   /* Make sure we record the final object, and get rid of it.  */
@@ -2398,7 +2398,7 @@ struct agent_expr *
 gen_eval_for_expr (CORE_ADDR scope, struct expression *expr)
 {
   struct cleanup *old_chain = 0;
-  struct agent_expr *ax = new_agent_expr (scope);
+  struct agent_expr *ax = new_agent_expr (expr->gdbarch, scope);
   union exp_element *pc;
   struct axs_value value;
 
@@ -2406,8 +2406,11 @@ gen_eval_for_expr (CORE_ADDR scope, struct expression *expr)
 
   pc = expr->elts;
   trace_kludge = 0;
+  value.optimized_out = 0;
   gen_expr (expr, &pc, ax, &value);
 
+  require_rvalue (ax, &value);
+
   /* Oh, and terminate.  */
   ax_simple (ax, aop_end);
 
@@ -2440,6 +2443,7 @@ agent_command (char *exp, int from_tty)
   old_chain = make_cleanup (free_current_contents, &expr);
   agent = gen_trace_for_expr (get_frame_pc (fi), expr);
   make_cleanup_free_agent_expr (agent);
+  ax_reqs (agent);
   ax_print (gdb_stdout, agent);
 
   /* It would be nice to call ax_reqs here to gather some general info
@@ -2475,6 +2479,7 @@ agent_eval_command (char *exp, int from_tty)
   old_chain = make_cleanup (free_current_contents, &expr);
   agent = gen_eval_for_expr (get_frame_pc (fi), expr);
   make_cleanup_free_agent_expr (agent);
+  ax_reqs (agent);
   ax_print (gdb_stdout, agent);
 
   /* It would be nice to call ax_reqs here to gather some general info

gdb/ax-general.c

@@ -40,15 +40,23 @@ static void generic_ext (struct agent_expr *x, enum agent_op op, int n);
 
 /* Allocate a new, empty agent expression.  */
 struct agent_expr *
-new_agent_expr (CORE_ADDR scope)
+new_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
 				   reallocation code is tested.  */
   x->buf = xmalloc (x->size);
+
+  x->gdbarch = gdbarch;
   x->scope = scope;
 
+  /* Bit vector for registers used.  */
+  x->reg_mask_len = 1;
+  x->reg_mask = xmalloc (x->reg_mask_len * sizeof (x->reg_mask[0]));
+  memset (x->reg_mask, 0, x->reg_mask_len * sizeof (x->reg_mask[0]));
+
   return x;
 }
 
@@ -57,6 +65,7 @@ void
 free_agent_expr (struct agent_expr *x)
 {
   xfree (x->buf);
+  xfree (x->reg_mask);
   xfree (x);
 }
 
@@ -355,6 +364,12 @@ 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]))
@@ -394,19 +409,37 @@ ax_print (struct ui_file *f, struct agent_expr *x)
     }
 }
 
-
+/* Add register REG to the register mask for expression AX.  */
-/* Given an agent expression AX, fill in an agent_reqs structure REQS
-   describing it.  */
 void
-ax_reqs (struct agent_expr *ax, struct agent_reqs *reqs)
+ax_reg_mask (struct agent_expr *ax, int reg)
+{
+  int 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 = xrealloc (ax->reg_mask,
+					      new_len * sizeof (ax->reg_mask[0]));
+      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 requirements and other descriptive
+   bits.  */
+void
+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 we have found a
      jump to offset i.  */
   char *targets = (char *) alloca (ax->len * sizeof (targets[0]));
@@ -423,20 +456,18 @@ ax_reqs (struct agent_expr *ax, struct agent_reqs *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;
+  ax->max_height = ax->min_height = height = 0;
-  reqs->flaw = agent_flaw_none;
+  ax->flaw = agent_flaw_none;
-  reqs->max_data_size = 0;
+  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;
+	  ax->flaw = agent_flaw_bad_instruction;
-	  xfree (reg_mask);
 	  return;
 	}
 
@@ -444,15 +475,13 @@ ax_reqs (struct agent_expr *ax, struct agent_reqs *reqs)
 
       if (!op->name)
 	{
-	  reqs->flaw = agent_flaw_bad_instruction;
+	  ax->flaw = agent_flaw_bad_instruction;
-	  xfree (reg_mask);
 	  return;
 	}
 
       if (i + 1 + op->op_size > ax->len)
 	{
-	  reqs->flaw = agent_flaw_incomplete_instruction;
+	  ax->flaw = agent_flaw_incomplete_instruction;
-	  xfree (reg_mask);
 	  return;
 	}
 
@@ -461,8 +490,7 @@ ax_reqs (struct agent_expr *ax, struct agent_reqs *reqs)
          source?  */
       if (targets[i] && (heights[i] != height))
 	{
-	  reqs->flaw = agent_flaw_height_mismatch;
+	  ax->flaw = agent_flaw_height_mismatch;
-	  xfree (reg_mask);
 	  return;
 	}
 
@@ -470,14 +498,14 @@ ax_reqs (struct agent_expr *ax, struct agent_reqs *reqs)
       heights[i] = height;
 
       height -= op->consumed;
-      if (height < reqs->min_height)
+      if (height < ax->min_height)
-	reqs->min_height = height;
+	ax->min_height = height;
       height += op->produced;
-      if (height > reqs->max_height)
+      if (height > ax->max_height)
-	reqs->max_height = height;
+	ax->max_height = height;
 
-      if (op->data_size > reqs->max_data_size)
+      if (op->data_size > ax->max_data_size)
-	reqs->max_data_size = op->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
@@ -488,8 +516,7 @@ ax_reqs (struct agent_expr *ax, struct agent_reqs *reqs)
 	  int target = read_const (ax, i + 1, 2);
 	  if (target < 0 || target >= ax->len)
 	    {
-	      reqs->flaw = agent_flaw_bad_jump;
+	      ax->flaw = agent_flaw_bad_jump;
-	      xfree (reg_mask);
 	      return;
 	    }
 
@@ -499,8 +526,7 @@ ax_reqs (struct agent_expr *ax, struct agent_reqs *reqs)
 	    {
 	      if (heights[target] != height)
 		{
-		  reqs->flaw = agent_flaw_height_mismatch;
+		  ax->flaw = agent_flaw_height_mismatch;
-		  xfree (reg_mask);
 		  return;
 		}
 	    }
@@ -517,8 +543,7 @@ ax_reqs (struct agent_expr *ax, struct agent_reqs *reqs)
 	{
 	  if (!targets[i + 3])
 	    {
-	      reqs->flaw = agent_flaw_hole;
+	      ax->flaw = agent_flaw_hole;
-	      xfree (reg_mask);
 	      return;
 	    }
 
@@ -529,22 +554,8 @@ ax_reqs (struct agent_expr *ax, struct agent_reqs *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.  */
+	  ax_reg_mask (ax, reg);
-	  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);
 	}
     }
 
@@ -552,12 +563,9 @@ ax_reqs (struct agent_expr *ax, struct agent_reqs *reqs)
   for (i = 0; i < ax->len; i++)
     if (targets[i] && !boundary[i])
       {
-	reqs->flaw = agent_flaw_bad_jump;
+	ax->flaw = agent_flaw_bad_jump;
-	xfree (reg_mask);
 	return;
       }
 
-  reqs->final_height = height;
+  ax->final_height = height;
-  reqs->reg_mask_len = reg_mask_len;
-  reqs->reg_mask = reg_mask;
 }

gdb/ax.h

@@ -51,6 +51,33 @@
    to the host GDB.  */
 
 
+/* Different kinds of flaws an agent expression might have, as
+   detected by ax_reqs.  */
+enum agent_flaws
+  {
+    agent_flaw_none = 0,	/* code is good */
+
+    /* There is an invalid instruction in the stream.  */
+    agent_flaw_bad_instruction,
+
+    /* There is an incomplete instruction at the end of the expression.  */
+    agent_flaw_incomplete_instruction,
+
+    /* ax_reqs was unable to prove that every jump target is to a
+       valid offset.  Valid offsets are within the bounds of the
+       expression, and to a valid instruction boundary.  */
+    agent_flaw_bad_jump,
+
+    /* ax_reqs was unable to prove to its satisfaction that, for each
+       jump target location, the stack will have the same height whether
+       that location is reached via a jump or by straight execution.  */
+    agent_flaw_height_mismatch,
+
+    /* ax_reqs was unable to prove that every instruction following
+       an unconditional jump was the target of some other jump.  */
+    agent_flaw_hole
+  };
+
 /* Agent expression data structures.  */
 
 /* The type of an element of the agent expression stack.
@@ -67,15 +94,57 @@ union agent_val
 /* A buffer containing a agent expression.  */
 struct agent_expr
   {
+    /* The bytes of the expression.  */
     unsigned char *buf;
-    int len;			/* number of characters used */
+
-    int size;			/* allocated size */
+    /* The number of bytecode in the expression.  */
+    int len;
+
+    /* Allocated space available currently.  */
+    int size;
+
+    /* The target architecture assumed to be in effect.  */
+    struct gdbarch *gdbarch;
+
+    /* The address to which the expression applies.  */
     CORE_ADDR scope;
+
+    /* If the following is not equal to agent_flaw_none, the rest of the
+       information in this structure is suspect.  */
+    enum agent_flaws flaw;
+
+    /* Number of elements left on stack at end; may be negative if expr
+       only consumes elements.  */
+    int final_height;
+
+    /* Maximum and minimum stack height, relative to initial height.  */
+    int max_height, min_height;
+
+    /* Largest `ref' or `const' opcode used, in bits.  Zero means the
+       expression has no such instructions.  */
+    int max_data_size;
+
+    /* Bit vector of registers needed.  Register R is needed iff
+
+       reg_mask[R / 8] & (1 << (R % 8))
+
+       is non-zero.  Note!  You may not assume that this bitmask is long
+       enough to hold bits for all the registers of the machine; the
+       agent expression code has no idea how many registers the machine
+       has.  However, the bitmask is reg_mask_len bytes long, so the
+       valid register numbers run from 0 to reg_mask_len * 8 - 1.
+
+       Also note that this mask may contain registers that are needed
+       for the original collection expression to work, but that are
+       not referenced by any bytecode.  This could, for example, occur
+       when collecting a local variable allocated to a register; the
+       compiler sets the mask bit and skips generating a bytecode whose
+       result is going to be discarded anyway.
+    */
+    int reg_mask_len;
+    unsigned char *reg_mask;
   };
 
-
-
-
 /* The actual values of the various bytecode operations.
 
    Other independent implementations of the agent bytecode engine will
@@ -143,7 +212,7 @@ enum agent_op
 /* Functions for building expressions.  */
 
 /* Allocate a new, empty agent expression.  */
-extern struct agent_expr *new_agent_expr (CORE_ADDR);
+extern struct agent_expr *new_agent_expr (struct gdbarch *, CORE_ADDR);
 
 /* Free a agent expression.  */
 extern void free_agent_expr (struct agent_expr *);
@@ -186,6 +255,9 @@ extern void ax_const_d (struct agent_expr *EXPR, LONGEST d);
    stack.  */
 extern void ax_reg (struct agent_expr *EXPR, int REG);
 
+/* Add the given register to the register mask of the expression.  */
+extern void ax_reg_mask (struct agent_expr *ax, int reg);
+
 /* Assemble code to operate on a trace state variable.  */
 extern void ax_tsv (struct agent_expr *expr, enum agent_op op, int num);
 
@@ -226,72 +298,8 @@ struct aop_map
 /* Map of the bytecodes, indexed by bytecode number.  */
 extern struct aop_map aop_map[];
 
-/* Different kinds of flaws an agent expression might have, as
+/* Given an agent expression AX, analyze and update its requirements.  */
-   detected by agent_reqs.  */
-enum agent_flaws
-  {
-    agent_flaw_none = 0,	/* code is good */
 
-    /* There is an invalid instruction in the stream.  */
+extern void ax_reqs (struct agent_expr *ax);
-    agent_flaw_bad_instruction,
-
-    /* There is an incomplete instruction at the end of the expression.  */
-    agent_flaw_incomplete_instruction,
-
-    /* agent_reqs was unable to prove that every jump target is to a
-       valid offset.  Valid offsets are within the bounds of the
-       expression, and to a valid instruction boundary.  */
-    agent_flaw_bad_jump,
-
-    /* agent_reqs was unable to prove to its satisfaction that, for each
-       jump target location, the stack will have the same height whether
-       that location is reached via a jump or by straight execution.  */
-    agent_flaw_height_mismatch,
-
-    /* agent_reqs was unable to prove that every instruction following
-       an unconditional jump was the target of some other jump.  */
-    agent_flaw_hole
-  };
-
-/* Structure describing the requirements of a bytecode expression.  */
-struct agent_reqs
-  {
-
-    /* If the following is not equal to agent_flaw_none, the rest of the
-       information in this structure is suspect.  */
-    enum agent_flaws flaw;
-
-    /* Number of elements left on stack at end; may be negative if expr
-       only consumes elements.  */
-    int final_height;
-
-    /* Maximum and minimum stack height, relative to initial height.  */
-    int max_height, min_height;
-
-    /* Largest `ref' or `const' opcode used, in bits.  Zero means the
-       expression has no such instructions.  */
-    int max_data_size;
-
-    /* Bit vector of registers used.  Register R is used iff
-
-       reg_mask[R / 8] & (1 << (R % 8))
-
-       is non-zero.  Note!  You may not assume that this bitmask is long
-       enough to hold bits for all the registers of the machine; the
-       agent expression code has no idea how many registers the machine
-       has.  However, the bitmask is reg_mask_len bytes long, so the
-       valid register numbers run from 0 to reg_mask_len * 8 - 1.  
-
-       We're assuming eight-bit bytes.  So sue me.
-
-       The caller should free reg_list when done.  */
-    int reg_mask_len;
-    unsigned char *reg_mask;
-  };
-
-
-/* Given an agent expression AX, fill in an agent_reqs structure REQS
-   describing it.  */
-extern void ax_reqs (struct agent_expr *ax, struct agent_reqs *reqs);
 
 #endif /* AGENTEXPR_H */

gdb/tracepoint.c

@@ -560,16 +560,16 @@ trace_actions_command (char *args, int from_tty)
    internal errors.  */
 
 static void
-report_agent_reqs_errors (struct agent_expr *aexpr, struct agent_reqs *areqs)
+report_agent_reqs_errors (struct agent_expr *aexpr)
 {
   /* All of the "flaws" are serious bytecode generation issues that
      should never occur.  */
-  if (areqs->flaw != agent_flaw_none)
+  if (aexpr->flaw != agent_flaw_none)
     internal_error (__FILE__, __LINE__, _("expression is malformed"));
 
   /* If analysis shows a stack underflow, GDB must have done something
      badly wrong in its bytecode generation.  */
-  if (areqs->min_height < 0)
+  if (aexpr->min_height < 0)
     internal_error (__FILE__, __LINE__,
 		    _("expression has min height < 0"));
 
@@ -579,7 +579,7 @@ report_agent_reqs_errors (struct agent_expr *aexpr, struct agent_reqs *areqs)
      depth roughly corresponds to parenthesization, so a limit of 20
      amounts to 20 levels of expression nesting, which is actually
      a pretty big hairy expression.  */
-  if (areqs->max_height > 20)
+  if (aexpr->max_height > 20)
     error (_("Expression is too complicated."));
 }
 
@@ -593,7 +593,6 @@ validate_actionline (char **line, struct breakpoint *t)
   char *p, *tmp_p;
   struct bp_location *loc;
   struct agent_expr *aexpr;
-  struct agent_reqs areqs;
 
   /* if EOF is typed, *line is NULL */
   if (*line == NULL)
@@ -663,10 +662,9 @@ validate_actionline (char **line, struct breakpoint *t)
 	      if (aexpr->len > MAX_AGENT_EXPR_LEN)
 		error (_("Expression is too complicated."));
 
-	      ax_reqs (aexpr, &areqs);
+	      ax_reqs (aexpr);
-	      (void) make_cleanup (xfree, areqs.reg_mask);
 
-	      report_agent_reqs_errors (aexpr, &areqs);
+	      report_agent_reqs_errors (aexpr);
 
 	      do_cleanups (old_chain);
 	    }
@@ -699,10 +697,8 @@ validate_actionline (char **line, struct breakpoint *t)
 	      if (aexpr->len > MAX_AGENT_EXPR_LEN)
 		error (_("Expression is too complicated."));
 
-	      ax_reqs (aexpr, &areqs);
+	      ax_reqs (aexpr);
-	      (void) make_cleanup (xfree, areqs.reg_mask);
+	      report_agent_reqs_errors (aexpr);
-
-	      report_agent_reqs_errors (aexpr, &areqs);
 
 	      do_cleanups (old_chain);
 	    }
@@ -974,7 +970,6 @@ collect_symbol (struct collection_list *collect,
     {
       struct agent_expr *aexpr;
       struct cleanup *old_chain1 = NULL;
-      struct agent_reqs areqs;
 
       aexpr = gen_trace_for_var (scope, gdbarch, sym);
 
@@ -990,26 +985,26 @@ collect_symbol (struct collection_list *collect,
 
       old_chain1 = make_cleanup_free_agent_expr (aexpr);
 
-      ax_reqs (aexpr, &areqs);
+      ax_reqs (aexpr);
 
-      report_agent_reqs_errors (aexpr, &areqs);
+      report_agent_reqs_errors (aexpr);
 
       discard_cleanups (old_chain1);
       add_aexpr (collect, aexpr);
 
       /* take care of the registers */
-      if (areqs.reg_mask_len > 0)
+      if (aexpr->reg_mask_len > 0)
 	{
 	  int ndx1, ndx2;
 
-	  for (ndx1 = 0; ndx1 < areqs.reg_mask_len; ndx1++)
+	  for (ndx1 = 0; ndx1 < aexpr->reg_mask_len; ndx1++)
 	    {
 	      QUIT;	/* allow user to bail out with ^C */
-	      if (areqs.reg_mask[ndx1] != 0)
+	      if (aexpr->reg_mask[ndx1] != 0)
 		{
 		  /* assume chars have 8 bits */
 		  for (ndx2 = 0; ndx2 < 8; ndx2++)
-		    if (areqs.reg_mask[ndx1] & (1 << ndx2))
+		    if (aexpr->reg_mask[ndx1] & (1 << ndx2))
 		      /* it's used -- record it */
 		      add_register (collect, ndx1 * 8 + ndx2);
 		}
@@ -1287,7 +1282,6 @@ encode_actions_1 (struct command_line *action,
 		  unsigned long addr, len;
 		  struct cleanup *old_chain = NULL;
 		  struct cleanup *old_chain1 = NULL;
-		  struct agent_reqs areqs;
 
 		  exp = parse_exp_1 (&action_exp, 
 				     block_for_pc (tloc->address), 1);
@@ -1333,27 +1327,27 @@ encode_actions_1 (struct command_line *action,
 
 		      old_chain1 = make_cleanup_free_agent_expr (aexpr);
 
-		      ax_reqs (aexpr, &areqs);
+		      ax_reqs (aexpr);
 
-		      report_agent_reqs_errors (aexpr, &areqs);
+		      report_agent_reqs_errors (aexpr);
 
 		      discard_cleanups (old_chain1);
 		      add_aexpr (collect, aexpr);
 
 		      /* take care of the registers */
-		      if (areqs.reg_mask_len > 0)
+		      if (aexpr->reg_mask_len > 0)
 			{
 			  int ndx1;
 			  int ndx2;
 
-			  for (ndx1 = 0; ndx1 < areqs.reg_mask_len; ndx1++)
+			  for (ndx1 = 0; ndx1 < aexpr->reg_mask_len; ndx1++)
 			    {
 			      QUIT;	/* allow user to bail out with ^C */
-			      if (areqs.reg_mask[ndx1] != 0)
+			      if (aexpr->reg_mask[ndx1] != 0)
 				{
 				  /* assume chars have 8 bits */
 				  for (ndx2 = 0; ndx2 < 8; ndx2++)
-				    if (areqs.reg_mask[ndx1] & (1 << ndx2))
+				    if (aexpr->reg_mask[ndx1] & (1 << ndx2))
 				      /* it's used -- record it */
 				      add_register (collect, 
 						    ndx1 * 8 + ndx2);
@@ -1379,7 +1373,6 @@ encode_actions_1 (struct command_line *action,
 		  unsigned long addr, len;
 		  struct cleanup *old_chain = NULL;
 		  struct cleanup *old_chain1 = NULL;
-		  struct agent_reqs areqs;
 
 		  exp = parse_exp_1 (&action_exp, 
 				     block_for_pc (tloc->address), 1);
@@ -1388,9 +1381,8 @@ encode_actions_1 (struct command_line *action,
 		  aexpr = gen_eval_for_expr (tloc->address, exp);
 		  old_chain1 = make_cleanup_free_agent_expr (aexpr);
 
-		  ax_reqs (aexpr, &areqs);
+		  ax_reqs (aexpr);
-
+		  report_agent_reqs_errors (aexpr);
-		  report_agent_reqs_errors (aexpr, &areqs);
 
 		  discard_cleanups (old_chain1);
 		  /* Even though we're not officially collecting, add