* parser-defs.h (struct exp_descriptor): New definition, containing

[deliverable/binutils-gdb.git] / gdb / eval.c

/* Evaluate expressions for GDB.

   Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
   1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003 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
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   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.  */

#include "defs.h"
#include "gdb_string.h"
#include "symtab.h"
#include "gdbtypes.h"
#include "value.h"
#include "expression.h"
#include "target.h"
#include "frame.h"
#include "language.h"           /* For CAST_IS_CONVERSION */
#include "f-lang.h"             /* for array bound stuff */
#include "cp-abi.h"
#include "infcall.h"
#include "objc-lang.h"
#include "block.h"
#include "parser-defs.h"

/* Defined in symtab.c */
extern int hp_som_som_object_present;

/* This is defined in valops.c */
extern int overload_resolution;

/* JYG: lookup rtti type of STRUCTOP_PTR when this is set to continue
   on with successful lookup for member/method of the rtti type. */
extern int objectprint;

/* Prototypes for local functions. */

static struct value *evaluate_subexp_for_sizeof (struct expression *, int *);

static struct value *evaluate_subexp_for_address (struct expression *,
                                                  int *, enum noside);

static struct value *evaluate_subexp (struct type *, struct expression *,
                                      int *, enum noside);

static char *get_label (struct expression *, int *);

static struct value *evaluate_struct_tuple (struct value *,
                                            struct expression *, int *,
                                            enum noside, int);

static LONGEST init_array_element (struct value *, struct value *,
                                   struct expression *, int *, enum noside,
                                   LONGEST, LONGEST);

static struct value *
evaluate_subexp (struct type *expect_type, struct expression *exp,
                 int *pos, enum noside noside)
{
  return (*exp->language_defn->la_exp_desc->evaluate_exp) 
    (expect_type, exp, pos, noside);
}
\f
/* Parse the string EXP as a C expression, evaluate it,
   and return the result as a number.  */

CORE_ADDR
parse_and_eval_address (char *exp)
{
  struct expression *expr = parse_expression (exp);
  CORE_ADDR addr;
  struct cleanup *old_chain =
    make_cleanup (free_current_contents, &expr);

  addr = value_as_address (evaluate_expression (expr));
  do_cleanups (old_chain);
  return addr;
}

/* Like parse_and_eval_address but takes a pointer to a char * variable
   and advanced that variable across the characters parsed.  */

CORE_ADDR
parse_and_eval_address_1 (char **expptr)
{
  struct expression *expr = parse_exp_1 (expptr, (struct block *) 0, 0);
  CORE_ADDR addr;
  struct cleanup *old_chain =
    make_cleanup (free_current_contents, &expr);

  addr = value_as_address (evaluate_expression (expr));
  do_cleanups (old_chain);
  return addr;
}

/* Like parse_and_eval_address, but treats the value of the expression
   as an integer, not an address, returns a LONGEST, not a CORE_ADDR */
LONGEST
parse_and_eval_long (char *exp)
{
  struct expression *expr = parse_expression (exp);
  LONGEST retval;
  struct cleanup *old_chain =
    make_cleanup (free_current_contents, &expr);

  retval = value_as_long (evaluate_expression (expr));
  do_cleanups (old_chain);
  return (retval);
}

struct value *
parse_and_eval (char *exp)
{
  struct expression *expr = parse_expression (exp);
  struct value *val;
  struct cleanup *old_chain =
    make_cleanup (free_current_contents, &expr);

  val = evaluate_expression (expr);
  do_cleanups (old_chain);
  return val;
}

/* Parse up to a comma (or to a closeparen)
   in the string EXPP as an expression, evaluate it, and return the value.
   EXPP is advanced to point to the comma.  */

struct value *
parse_to_comma_and_eval (char **expp)
{
  struct expression *expr = parse_exp_1 (expp, (struct block *) 0, 1);
  struct value *val;
  struct cleanup *old_chain =
    make_cleanup (free_current_contents, &expr);

  val = evaluate_expression (expr);
  do_cleanups (old_chain);
  return val;
}
\f
/* Evaluate an expression in internal prefix form
   such as is constructed by parse.y.

   See expression.h for info on the format of an expression.  */

struct value *
evaluate_expression (struct expression *exp)
{
  int pc = 0;
  return evaluate_subexp (NULL_TYPE, exp, &pc, EVAL_NORMAL);
}

/* Evaluate an expression, avoiding all memory references
   and getting a value whose type alone is correct.  */

struct value *
evaluate_type (struct expression *exp)
{
  int pc = 0;
  return evaluate_subexp (NULL_TYPE, exp, &pc, EVAL_AVOID_SIDE_EFFECTS);
}

/* If the next expression is an OP_LABELED, skips past it,
   returning the label.  Otherwise, does nothing and returns NULL. */

static char *
get_label (struct expression *exp, int *pos)
{
  if (exp->elts[*pos].opcode == OP_LABELED)
    {
      int pc = (*pos)++;
      char *name = &exp->elts[pc + 2].string;
      int tem = longest_to_int (exp->elts[pc + 1].longconst);
      (*pos) += 3 + BYTES_TO_EXP_ELEM (tem + 1);
      return name;
    }
  else
    return NULL;
}

/* This function evaluates tuples (in (the deleted) Chill) or
   brace-initializers (in C/C++) for structure types.  */

static struct value *
evaluate_struct_tuple (struct value *struct_val,
                       struct expression *exp,
                       int *pos, enum noside noside, int nargs)
{
  struct type *struct_type = check_typedef (VALUE_TYPE (struct_val));
  struct type *substruct_type = struct_type;
  struct type *field_type;
  int fieldno = -1;
  int variantno = -1;
  int subfieldno = -1;
  while (--nargs >= 0)
    {
      int pc = *pos;
      struct value *val = NULL;
      int nlabels = 0;
      int bitpos, bitsize;
      char *addr;

      /* Skip past the labels, and count them. */
      while (get_label (exp, pos) != NULL)
        nlabels++;

      do
        {
          char *label = get_label (exp, &pc);
          if (label)
            {
              for (fieldno = 0; fieldno < TYPE_NFIELDS (struct_type);
                   fieldno++)
                {
                  char *field_name = TYPE_FIELD_NAME (struct_type, fieldno);
                  if (field_name != NULL && STREQ (field_name, label))
                    {
                      variantno = -1;
                      subfieldno = fieldno;
                      substruct_type = struct_type;
                      goto found;
                    }
                }
              for (fieldno = 0; fieldno < TYPE_NFIELDS (struct_type);
                   fieldno++)
                {
                  char *field_name = TYPE_FIELD_NAME (struct_type, fieldno);
                  field_type = TYPE_FIELD_TYPE (struct_type, fieldno);
                  if ((field_name == 0 || *field_name == '\0')
                      && TYPE_CODE (field_type) == TYPE_CODE_UNION)
                    {
                      variantno = 0;
                      for (; variantno < TYPE_NFIELDS (field_type);
                           variantno++)
                        {
                          substruct_type
                            = TYPE_FIELD_TYPE (field_type, variantno);
                          if (TYPE_CODE (substruct_type) == TYPE_CODE_STRUCT)
                            {
                              for (subfieldno = 0;
                                 subfieldno < TYPE_NFIELDS (substruct_type);
                                   subfieldno++)
                                {
                                  if (STREQ (TYPE_FIELD_NAME (substruct_type,
                                                              subfieldno),
                                             label))
                                    {
                                      goto found;
                                    }
                                }
                            }
                        }
                    }
                }
              error ("there is no field named %s", label);
            found:
              ;
            }
          else
            {
              /* Unlabelled tuple element - go to next field. */
              if (variantno >= 0)
                {
                  subfieldno++;
                  if (subfieldno >= TYPE_NFIELDS (substruct_type))
                    {
                      variantno = -1;
                      substruct_type = struct_type;
                    }
                }
              if (variantno < 0)
                {
                  fieldno++;
                  subfieldno = fieldno;
                  if (fieldno >= TYPE_NFIELDS (struct_type))
                    error ("too many initializers");
                  field_type = TYPE_FIELD_TYPE (struct_type, fieldno);
                  if (TYPE_CODE (field_type) == TYPE_CODE_UNION
                      && TYPE_FIELD_NAME (struct_type, fieldno)[0] == '0')
                    error ("don't know which variant you want to set");
                }
            }

          /* Here, struct_type is the type of the inner struct,
             while substruct_type is the type of the inner struct.
             These are the same for normal structures, but a variant struct
             contains anonymous union fields that contain substruct fields.
             The value fieldno is the index of the top-level (normal or
             anonymous union) field in struct_field, while the value
             subfieldno is the index of the actual real (named inner) field
             in substruct_type. */

          field_type = TYPE_FIELD_TYPE (substruct_type, subfieldno);
          if (val == 0)
            val = evaluate_subexp (field_type, exp, pos, noside);

          /* Now actually set the field in struct_val. */

          /* Assign val to field fieldno. */
          if (VALUE_TYPE (val) != field_type)
            val = value_cast (field_type, val);

          bitsize = TYPE_FIELD_BITSIZE (substruct_type, subfieldno);
          bitpos = TYPE_FIELD_BITPOS (struct_type, fieldno);
          if (variantno >= 0)
            bitpos += TYPE_FIELD_BITPOS (substruct_type, subfieldno);
          addr = VALUE_CONTENTS (struct_val) + bitpos / 8;
          if (bitsize)
            modify_field (addr, value_as_long (val),
                          bitpos % 8, bitsize);
          else
            memcpy (addr, VALUE_CONTENTS (val),
                    TYPE_LENGTH (VALUE_TYPE (val)));
        }
      while (--nlabels > 0);
    }
  return struct_val;
}

/* Recursive helper function for setting elements of array tuples for
   (the deleted) Chill.  The target is ARRAY (which has bounds
   LOW_BOUND to HIGH_BOUND); the element value is ELEMENT; EXP, POS
   and NOSIDE are as usual.  Evaluates index expresions and sets the
   specified element(s) of ARRAY to ELEMENT.  Returns last index
   value.  */

static LONGEST
init_array_element (struct value *array, struct value *element,
                    struct expression *exp, int *pos,
                    enum noside noside, LONGEST low_bound, LONGEST high_bound)
{
  LONGEST index;
  int element_size = TYPE_LENGTH (VALUE_TYPE (element));
  if (exp->elts[*pos].opcode == BINOP_COMMA)
    {
      (*pos)++;
      init_array_element (array, element, exp, pos, noside,
                          low_bound, high_bound);
      return init_array_element (array, element,
                                 exp, pos, noside, low_bound, high_bound);
    }
  else if (exp->elts[*pos].opcode == BINOP_RANGE)
    {
      LONGEST low, high;
      (*pos)++;
      low = value_as_long (evaluate_subexp (NULL_TYPE, exp, pos, noside));
      high = value_as_long (evaluate_subexp (NULL_TYPE, exp, pos, noside));
      if (low < low_bound || high > high_bound)
        error ("tuple range index out of range");
      for (index = low; index <= high; index++)
        {
          memcpy (VALUE_CONTENTS_RAW (array)
                  + (index - low_bound) * element_size,
                  VALUE_CONTENTS (element), element_size);
        }
    }
  else
    {
      index = value_as_long (evaluate_subexp (NULL_TYPE, exp, pos, noside));
      if (index < low_bound || index > high_bound)
        error ("tuple index out of range");
      memcpy (VALUE_CONTENTS_RAW (array) + (index - low_bound) * element_size,
              VALUE_CONTENTS (element), element_size);
    }
  return index;
}

struct value *
evaluate_subexp_standard (struct type *expect_type,
                          struct expression *exp, int *pos,
                          enum noside noside)
{
  enum exp_opcode op;
  int tem, tem2, tem3;
  int pc, pc2 = 0, oldpos;
  struct value *arg1 = NULL;
  struct value *arg2 = NULL;
  struct value *arg3;
  struct type *type;
  int nargs;
  struct value **argvec;
  int upper, lower, retcode;
  int code;
  int ix;
  long mem_offset;
  struct type **arg_types;
  int save_pos1;

  pc = (*pos)++;
  op = exp->elts[pc].opcode;

  switch (op)
    {
    case OP_SCOPE:
      tem = longest_to_int (exp->elts[pc + 2].longconst);
      (*pos) += 4 + BYTES_TO_EXP_ELEM (tem + 1);
      arg1 = value_struct_elt_for_reference (exp->elts[pc + 1].type,
                                             0,
                                             exp->elts[pc + 1].type,
                                             &exp->elts[pc + 3].string,
                                             NULL_TYPE);
      if (arg1 == NULL)
        error ("There is no field named %s", &exp->elts[pc + 3].string);
      return arg1;

    case OP_LONG:
      (*pos) += 3;
      return value_from_longest (exp->elts[pc + 1].type,
                                 exp->elts[pc + 2].longconst);

    case OP_DOUBLE:
      (*pos) += 3;
      return value_from_double (exp->elts[pc + 1].type,
                                exp->elts[pc + 2].doubleconst);

    case OP_VAR_VALUE:
      (*pos) += 3;
      if (noside == EVAL_SKIP)
        goto nosideret;

      /* JYG: We used to just return value_zero of the symbol type
         if we're asked to avoid side effects.  Otherwise we return
         value_of_variable (...).  However I'm not sure if
         value_of_variable () has any side effect.
         We need a full value object returned here for whatis_exp ()
         to call evaluate_type () and then pass the full value to
         value_rtti_target_type () if we are dealing with a pointer
         or reference to a base class and print object is on. */

        return value_of_variable (exp->elts[pc + 2].symbol,
                                  exp->elts[pc + 1].block);

    case OP_LAST:
      (*pos) += 2;
      return
        access_value_history (longest_to_int (exp->elts[pc + 1].longconst));

    case OP_REGISTER:
      {
        int regno = longest_to_int (exp->elts[pc + 1].longconst);
        struct value *val = value_of_register (regno, get_selected_frame ());
        (*pos) += 2;
        if (val == NULL)
          error ("Value of register %s not available.",
                 frame_map_regnum_to_name (get_selected_frame (), regno));
        else
          return val;
      }
    case OP_BOOL:
      (*pos) += 2;
      return value_from_longest (LA_BOOL_TYPE,
                                 exp->elts[pc + 1].longconst);

    case OP_INTERNALVAR:
      (*pos) += 2;
      return value_of_internalvar (exp->elts[pc + 1].internalvar);

    case OP_STRING:
      tem = longest_to_int (exp->elts[pc + 1].longconst);
      (*pos) += 3 + BYTES_TO_EXP_ELEM (tem + 1);
      if (noside == EVAL_SKIP)
        goto nosideret;
      return value_string (&exp->elts[pc + 2].string, tem);

    case OP_OBJC_NSSTRING:              /* Objective C Foundation Class NSString constant.  */
      tem = longest_to_int (exp->elts[pc + 1].longconst);
      (*pos) += 3 + BYTES_TO_EXP_ELEM (tem + 1);
      if (noside == EVAL_SKIP)
        {
          goto nosideret;
        }
      return (struct value *) value_nsstring (&exp->elts[pc + 2].string, tem + 1);

    case OP_BITSTRING:
      tem = longest_to_int (exp->elts[pc + 1].longconst);
      (*pos)
        += 3 + BYTES_TO_EXP_ELEM ((tem + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT);
      if (noside == EVAL_SKIP)
        goto nosideret;
      return value_bitstring (&exp->elts[pc + 2].string, tem);
      break;

    case OP_ARRAY:
      (*pos) += 3;
      tem2 = longest_to_int (exp->elts[pc + 1].longconst);
      tem3 = longest_to_int (exp->elts[pc + 2].longconst);
      nargs = tem3 - tem2 + 1;
      type = expect_type ? check_typedef (expect_type) : NULL_TYPE;

      if (expect_type != NULL_TYPE && noside != EVAL_SKIP
          && TYPE_CODE (type) == TYPE_CODE_STRUCT)
        {
          struct value *rec = allocate_value (expect_type);
          memset (VALUE_CONTENTS_RAW (rec), '\0', TYPE_LENGTH (type));
          return evaluate_struct_tuple (rec, exp, pos, noside, nargs);
        }

      if (expect_type != NULL_TYPE && noside != EVAL_SKIP
          && TYPE_CODE (type) == TYPE_CODE_ARRAY)
        {
          struct type *range_type = TYPE_FIELD_TYPE (type, 0);
          struct type *element_type = TYPE_TARGET_TYPE (type);
          struct value *array = allocate_value (expect_type);
          int element_size = TYPE_LENGTH (check_typedef (element_type));
          LONGEST low_bound, high_bound, index;
          if (get_discrete_bounds (range_type, &low_bound, &high_bound) < 0)
            {
              low_bound = 0;
              high_bound = (TYPE_LENGTH (type) / element_size) - 1;
            }
          index = low_bound;
          memset (VALUE_CONTENTS_RAW (array), 0, TYPE_LENGTH (expect_type));
          for (tem = nargs; --nargs >= 0;)
            {
              struct value *element;
              int index_pc = 0;
              if (exp->elts[*pos].opcode == BINOP_RANGE)
                {
                  index_pc = ++(*pos);
                  evaluate_subexp (NULL_TYPE, exp, pos, EVAL_SKIP);
                }
              element = evaluate_subexp (element_type, exp, pos, noside);
              if (VALUE_TYPE (element) != element_type)
                element = value_cast (element_type, element);
              if (index_pc)
                {
                  int continue_pc = *pos;
                  *pos = index_pc;
                  index = init_array_element (array, element, exp, pos, noside,
                                              low_bound, high_bound);
                  *pos = continue_pc;
                }
              else
                {
                  if (index > high_bound)
                    /* to avoid memory corruption */
                    error ("Too many array elements");
                  memcpy (VALUE_CONTENTS_RAW (array)
                          + (index - low_bound) * element_size,
                          VALUE_CONTENTS (element),
                          element_size);
                }
              index++;
            }
          return array;
        }

      if (expect_type != NULL_TYPE && noside != EVAL_SKIP
          && TYPE_CODE (type) == TYPE_CODE_SET)
        {
          struct value *set = allocate_value (expect_type);
          char *valaddr = VALUE_CONTENTS_RAW (set);
          struct type *element_type = TYPE_INDEX_TYPE (type);
          struct type *check_type = element_type;
          LONGEST low_bound, high_bound;

          /* get targettype of elementtype */
          while (TYPE_CODE (check_type) == TYPE_CODE_RANGE ||
                 TYPE_CODE (check_type) == TYPE_CODE_TYPEDEF)
            check_type = TYPE_TARGET_TYPE (check_type);

          if (get_discrete_bounds (element_type, &low_bound, &high_bound) < 0)
            error ("(power)set type with unknown size");
          memset (valaddr, '\0', TYPE_LENGTH (type));
          for (tem = 0; tem < nargs; tem++)
            {
              LONGEST range_low, range_high;
              struct type *range_low_type, *range_high_type;
              struct value *elem_val;
              if (exp->elts[*pos].opcode == BINOP_RANGE)
                {
                  (*pos)++;
                  elem_val = evaluate_subexp (element_type, exp, pos, noside);
                  range_low_type = VALUE_TYPE (elem_val);
                  range_low = value_as_long (elem_val);
                  elem_val = evaluate_subexp (element_type, exp, pos, noside);
                  range_high_type = VALUE_TYPE (elem_val);
                  range_high = value_as_long (elem_val);
                }
              else
                {
                  elem_val = evaluate_subexp (element_type, exp, pos, noside);
                  range_low_type = range_high_type = VALUE_TYPE (elem_val);
                  range_low = range_high = value_as_long (elem_val);
                }
              /* check types of elements to avoid mixture of elements from
                 different types. Also check if type of element is "compatible"
                 with element type of powerset */
              if (TYPE_CODE (range_low_type) == TYPE_CODE_RANGE)
                range_low_type = TYPE_TARGET_TYPE (range_low_type);
              if (TYPE_CODE (range_high_type) == TYPE_CODE_RANGE)
                range_high_type = TYPE_TARGET_TYPE (range_high_type);
              if ((TYPE_CODE (range_low_type) != TYPE_CODE (range_high_type)) ||
                  (TYPE_CODE (range_low_type) == TYPE_CODE_ENUM &&
                   (range_low_type != range_high_type)))
                /* different element modes */
                error ("POWERSET tuple elements of different mode");
              if ((TYPE_CODE (check_type) != TYPE_CODE (range_low_type)) ||
                  (TYPE_CODE (check_type) == TYPE_CODE_ENUM &&
                   range_low_type != check_type))
                error ("incompatible POWERSET tuple elements");
              if (range_low > range_high)
                {
                  warning ("empty POWERSET tuple range");
                  continue;
                }
              if (range_low < low_bound || range_high > high_bound)
                error ("POWERSET tuple element out of range");
              range_low -= low_bound;
              range_high -= low_bound;
              for (; range_low <= range_high; range_low++)
                {
                  int bit_index = (unsigned) range_low % TARGET_CHAR_BIT;
                  if (BITS_BIG_ENDIAN)
                    bit_index = TARGET_CHAR_BIT - 1 - bit_index;
                  valaddr[(unsigned) range_low / TARGET_CHAR_BIT]
                    |= 1 << bit_index;
                }
            }
          return set;
        }

      argvec = (struct value **) alloca (sizeof (struct value *) * nargs);
      for (tem = 0; tem < nargs; tem++)
        {
          /* Ensure that array expressions are coerced into pointer objects. */
          argvec[tem] = evaluate_subexp_with_coercion (exp, pos, noside);
        }
      if (noside == EVAL_SKIP)
        goto nosideret;
      return value_array (tem2, tem3, argvec);

    case TERNOP_SLICE:
      {
        struct value *array = evaluate_subexp (NULL_TYPE, exp, pos, noside);
        int lowbound
        = value_as_long (evaluate_subexp (NULL_TYPE, exp, pos, noside));
        int upper
        = value_as_long (evaluate_subexp (NULL_TYPE, exp, pos, noside));
        if (noside == EVAL_SKIP)
          goto nosideret;
        return value_slice (array, lowbound, upper - lowbound + 1);
      }

    case TERNOP_SLICE_COUNT:
      {
        struct value *array = evaluate_subexp (NULL_TYPE, exp, pos, noside);
        int lowbound
        = value_as_long (evaluate_subexp (NULL_TYPE, exp, pos, noside));
        int length
        = value_as_long (evaluate_subexp (NULL_TYPE, exp, pos, noside));
        return value_slice (array, lowbound, length);
      }

    case TERNOP_COND:
      /* Skip third and second args to evaluate the first one.  */
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      if (value_logical_not (arg1))
        {
          evaluate_subexp (NULL_TYPE, exp, pos, EVAL_SKIP);
          return evaluate_subexp (NULL_TYPE, exp, pos, noside);
        }
      else
        {
          arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
          evaluate_subexp (NULL_TYPE, exp, pos, EVAL_SKIP);
          return arg2;
        }

    case OP_OBJC_SELECTOR:
      {                         /* Objective C @selector operator.  */
        char *sel = &exp->elts[pc + 2].string;
        int len = longest_to_int (exp->elts[pc + 1].longconst);

        (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);
        if (noside == EVAL_SKIP)
          goto nosideret;

        if (sel[len] != 0)
          sel[len] = 0;         /* Make sure it's terminated.  */
        return value_from_longest (lookup_pointer_type (builtin_type_void),
                                   lookup_child_selector (sel));
      }

    case OP_OBJC_MSGCALL:
      {                         /* Objective C message (method) call.  */

        static unsigned long responds_selector = 0;
        static unsigned long method_selector = 0;

        unsigned long selector = 0;

        int using_gcc = 0;
        int struct_return = 0;
        int sub_no_side = 0;

        static struct value *msg_send = NULL;
        static struct value *msg_send_stret = NULL;
        static int gnu_runtime = 0;

        struct value *target = NULL;
        struct value *method = NULL;
        struct value *called_method = NULL; 

        struct type *selector_type = NULL;

        struct value *ret = NULL;
        CORE_ADDR addr = 0;

        selector = exp->elts[pc + 1].longconst;
        nargs = exp->elts[pc + 2].longconst;
        argvec = (struct value **) alloca (sizeof (struct value *) 
                                           * (nargs + 5));

        (*pos) += 3;

        selector_type = lookup_pointer_type (builtin_type_void);
        if (noside == EVAL_AVOID_SIDE_EFFECTS)
          sub_no_side = EVAL_NORMAL;
        else
          sub_no_side = noside;

        target = evaluate_subexp (selector_type, exp, pos, sub_no_side);

        if (value_as_long (target) == 0)
          return value_from_longest (builtin_type_long, 0);
        
        if (lookup_minimal_symbol ("objc_msg_lookup", 0, 0))
          gnu_runtime = 1;
        
        /* Find the method dispatch (Apple runtime) or method lookup
           (GNU runtime) function for Objective-C.  These will be used
           to lookup the symbol information for the method.  If we
           can't find any symbol information, then we'll use these to
           call the method, otherwise we can call the method
           directly. The msg_send_stret function is used in the special
           case of a method that returns a structure (Apple runtime 
           only).  */
        if (gnu_runtime)
          {
            msg_send = find_function_in_inferior ("objc_msg_lookup");
            msg_send_stret = find_function_in_inferior ("objc_msg_lookup");
          }
        else
          {
            msg_send = find_function_in_inferior ("objc_msgSend");
            /* Special dispatcher for methods returning structs */
            msg_send_stret = find_function_in_inferior ("objc_msgSend_stret");
          }

        /* Verify the target object responds to this method. The
           standard top-level 'Object' class uses a different name for
           the verification method than the non-standard, but more
           often used, 'NSObject' class. Make sure we check for both. */

        responds_selector = lookup_child_selector ("respondsToSelector:");
        if (responds_selector == 0)
          responds_selector = lookup_child_selector ("respondsTo:");
        
        if (responds_selector == 0)
          error ("no 'respondsTo:' or 'respondsToSelector:' method");
        
        method_selector = lookup_child_selector ("methodForSelector:");
        if (method_selector == 0)
          method_selector = lookup_child_selector ("methodFor:");
        
        if (method_selector == 0)
          error ("no 'methodFor:' or 'methodForSelector:' method");

        /* Call the verification method, to make sure that the target
         class implements the desired method. */

        argvec[0] = msg_send;
        argvec[1] = target;
        argvec[2] = value_from_longest (builtin_type_long, responds_selector);
        argvec[3] = value_from_longest (builtin_type_long, selector);
        argvec[4] = 0;

        ret = call_function_by_hand (argvec[0], 3, argvec + 1);
        if (gnu_runtime)
          {
            /* Function objc_msg_lookup returns a pointer.  */
            argvec[0] = ret;
            ret = call_function_by_hand (argvec[0], 3, argvec + 1);
          }
        if (value_as_long (ret) == 0)
          error ("Target does not respond to this message selector.");

        /* Call "methodForSelector:" method, to get the address of a
           function method that implements this selector for this
           class.  If we can find a symbol at that address, then we
           know the return type, parameter types etc.  (that's a good
           thing). */

        argvec[0] = msg_send;
        argvec[1] = target;
        argvec[2] = value_from_longest (builtin_type_long, method_selector);
        argvec[3] = value_from_longest (builtin_type_long, selector);
        argvec[4] = 0;

        ret = call_function_by_hand (argvec[0], 3, argvec + 1);
        if (gnu_runtime)
          {
            argvec[0] = ret;
            ret = call_function_by_hand (argvec[0], 3, argvec + 1);
          }

        /* ret should now be the selector.  */

        addr = value_as_long (ret);
        if (addr)
          {
            struct symbol *sym = NULL;
            /* Is it a high_level symbol?  */

            sym = find_pc_function (addr);
            if (sym != NULL) 
              method = value_of_variable (sym, 0);
          }

        /* If we found a method with symbol information, check to see
           if it returns a struct.  Otherwise assume it doesn't.  */

        if (method)
          {
            struct block *b;
            CORE_ADDR funaddr;
            struct type *value_type;

            funaddr = find_function_addr (method, &value_type);

            b = block_for_pc (funaddr);

            /* If compiled without -g, assume GCC 2.  */
            using_gcc = (b == NULL ? 2 : BLOCK_GCC_COMPILED (b));

            CHECK_TYPEDEF (value_type);
          
            if ((value_type == NULL) 
                || (TYPE_CODE(value_type) == TYPE_CODE_ERROR))
              {
                if (expect_type != NULL)
                  value_type = expect_type;
              }

            struct_return = using_struct_return (value_type, using_gcc);
          }
        else if (expect_type != NULL)
          {
            struct_return = using_struct_return (check_typedef (expect_type), using_gcc);
          }
        
        /* Found a function symbol.  Now we will substitute its
           value in place of the message dispatcher (obj_msgSend),
           so that we call the method directly instead of thru
           the dispatcher.  The main reason for doing this is that
           we can now evaluate the return value and parameter values
           according to their known data types, in case we need to
           do things like promotion, dereferencing, special handling
           of structs and doubles, etc.
          
           We want to use the type signature of 'method', but still
           jump to objc_msgSend() or objc_msgSend_stret() to better
           mimic the behavior of the runtime.  */
        
        if (method)
          {
            if (TYPE_CODE (VALUE_TYPE (method)) != TYPE_CODE_FUNC)
              error ("method address has symbol information with non-function type; skipping");
            if (struct_return)
              VALUE_ADDRESS (method) = value_as_address (msg_send_stret);
            else
              VALUE_ADDRESS (method) = value_as_address (msg_send);
            called_method = method;
          }
        else
          {
            if (struct_return)
              called_method = msg_send_stret;
            else
              called_method = msg_send;
          }

        if (noside == EVAL_SKIP)
          goto nosideret;

        if (noside == EVAL_AVOID_SIDE_EFFECTS)
          {
            /* If the return type doesn't look like a function type,
               call an error.  This can happen if somebody tries to
               turn a variable into a function call. This is here
               because people often want to call, eg, strcmp, which
               gdb doesn't know is a function.  If gdb isn't asked for
               it's opinion (ie. through "whatis"), it won't offer
               it. */

            struct type *type = VALUE_TYPE (called_method);
            if (type && TYPE_CODE (type) == TYPE_CODE_PTR)
              type = TYPE_TARGET_TYPE (type);
            type = TYPE_TARGET_TYPE (type);

            if (type)
            {
              if ((TYPE_CODE (type) == TYPE_CODE_ERROR) && expect_type)
                return allocate_value (expect_type);
              else
                return allocate_value (type);
            }
            else
              error ("Expression of type other than \"method returning ...\" used as a method");
          }

        /* Now depending on whether we found a symbol for the method,
           we will either call the runtime dispatcher or the method
           directly.  */

        argvec[0] = called_method;
        argvec[1] = target;
        argvec[2] = value_from_longest (builtin_type_long, selector);
        /* User-supplied arguments.  */
        for (tem = 0; tem < nargs; tem++)
          argvec[tem + 3] = evaluate_subexp_with_coercion (exp, pos, noside);
        argvec[tem + 3] = 0;

        if (gnu_runtime && (method != NULL))
          {
            ret = call_function_by_hand (argvec[0], nargs + 2, argvec + 1);
            /* Function objc_msg_lookup returns a pointer.  */
            argvec[0] = ret;
            ret = call_function_by_hand (argvec[0], nargs + 2, argvec + 1);
          }
        else
          ret = call_function_by_hand (argvec[0], nargs + 2, argvec + 1);

        return ret;
      }
      break;

    case OP_FUNCALL:
      (*pos) += 2;
      op = exp->elts[*pos].opcode;
      nargs = longest_to_int (exp->elts[pc + 1].longconst);
      /* Allocate arg vector, including space for the function to be
         called in argvec[0] and a terminating NULL */
      argvec = (struct value **) alloca (sizeof (struct value *) * (nargs + 3));
      if (op == STRUCTOP_MEMBER || op == STRUCTOP_MPTR)
        {
          LONGEST fnptr;

          /* 1997-08-01 Currently we do not support function invocation
             via pointers-to-methods with HP aCC. Pointer does not point
             to the function, but possibly to some thunk. */
          if (hp_som_som_object_present)
            {
              error ("Not implemented: function invocation through pointer to method with HP aCC");
            }

          nargs++;
          /* First, evaluate the structure into arg2 */
          pc2 = (*pos)++;

          if (noside == EVAL_SKIP)
            goto nosideret;

          if (op == STRUCTOP_MEMBER)
            {
              arg2 = evaluate_subexp_for_address (exp, pos, noside);
            }
          else
            {
              arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
            }

          /* If the function is a virtual function, then the
             aggregate value (providing the structure) plays
             its part by providing the vtable.  Otherwise,
             it is just along for the ride: call the function
             directly.  */

          arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);

          fnptr = value_as_long (arg1);

          if (METHOD_PTR_IS_VIRTUAL (fnptr))
            {
              int fnoffset = METHOD_PTR_TO_VOFFSET (fnptr);
              struct type *basetype;
              struct type *domain_type =
              TYPE_DOMAIN_TYPE (TYPE_TARGET_TYPE (VALUE_TYPE (arg1)));
              int i, j;
              basetype = TYPE_TARGET_TYPE (VALUE_TYPE (arg2));
              if (domain_type != basetype)
                arg2 = value_cast (lookup_pointer_type (domain_type), arg2);
              basetype = TYPE_VPTR_BASETYPE (domain_type);
              for (i = TYPE_NFN_FIELDS (basetype) - 1; i >= 0; i--)
                {
                  struct fn_field *f = TYPE_FN_FIELDLIST1 (basetype, i);
                  /* If one is virtual, then all are virtual.  */
                  if (TYPE_FN_FIELD_VIRTUAL_P (f, 0))
                    for (j = TYPE_FN_FIELDLIST_LENGTH (basetype, i) - 1; j >= 0; --j)
                      if ((int) TYPE_FN_FIELD_VOFFSET (f, j) == fnoffset)
                        {
                          struct value *temp = value_ind (arg2);
                          arg1 = value_virtual_fn_field (&temp, f, j, domain_type, 0);
                          arg2 = value_addr (temp);
                          goto got_it;
                        }
                }
              if (i < 0)
                error ("virtual function at index %d not found", fnoffset);
            }
          else
            {
              VALUE_TYPE (arg1) = lookup_pointer_type (TYPE_TARGET_TYPE (VALUE_TYPE (arg1)));
            }
        got_it:

          /* Now, say which argument to start evaluating from */
          tem = 2;
        }
      else if (op == STRUCTOP_STRUCT || op == STRUCTOP_PTR)
        {
          /* Hair for method invocations */
          int tem2;

          nargs++;
          /* First, evaluate the structure into arg2 */
          pc2 = (*pos)++;
          tem2 = longest_to_int (exp->elts[pc2 + 1].longconst);
          *pos += 3 + BYTES_TO_EXP_ELEM (tem2 + 1);
          if (noside == EVAL_SKIP)
            goto nosideret;

          if (op == STRUCTOP_STRUCT)
            {
              /* If v is a variable in a register, and the user types
                 v.method (), this will produce an error, because v has
                 no address.

                 A possible way around this would be to allocate a
                 copy of the variable on the stack, copy in the
                 contents, call the function, and copy out the
                 contents.  I.e. convert this from call by reference
                 to call by copy-return (or whatever it's called).
                 However, this does not work because it is not the
                 same: the method being called could stash a copy of
                 the address, and then future uses through that address
                 (after the method returns) would be expected to
                 use the variable itself, not some copy of it.  */
              arg2 = evaluate_subexp_for_address (exp, pos, noside);
            }
          else
            {
              arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
            }
          /* Now, say which argument to start evaluating from */
          tem = 2;
        }
      else
        {
          /* Non-method function call */
          save_pos1 = *pos;
          argvec[0] = evaluate_subexp_with_coercion (exp, pos, noside);
          tem = 1;
          type = VALUE_TYPE (argvec[0]);
          if (type && TYPE_CODE (type) == TYPE_CODE_PTR)
            type = TYPE_TARGET_TYPE (type);
          if (type && TYPE_CODE (type) == TYPE_CODE_FUNC)
            {
              for (; tem <= nargs && tem <= TYPE_NFIELDS (type); tem++)
                {
                  /* pai: FIXME This seems to be coercing arguments before
                   * overload resolution has been done! */
                  argvec[tem] = evaluate_subexp (TYPE_FIELD_TYPE (type, tem - 1),
                                                 exp, pos, noside);
                }
            }
        }

      /* Evaluate arguments */
      for (; tem <= nargs; tem++)
        {
          /* Ensure that array expressions are coerced into pointer objects. */
          argvec[tem] = evaluate_subexp_with_coercion (exp, pos, noside);
        }

      /* signal end of arglist */
      argvec[tem] = 0;

      if (op == STRUCTOP_STRUCT || op == STRUCTOP_PTR)
        {
          int static_memfuncp;
          char tstr[256];

          /* Method invocation : stuff "this" as first parameter */
          argvec[1] = arg2;
          /* Name of method from expression */
          strcpy (tstr, &exp->elts[pc2 + 2].string);

          if (overload_resolution && (exp->language_defn->la_language == language_cplus))
            {
              /* Language is C++, do some overload resolution before evaluation */
              struct value *valp = NULL;

              /* Prepare list of argument types for overload resolution */
              arg_types = (struct type **) alloca (nargs * (sizeof (struct type *)));
              for (ix = 1; ix <= nargs; ix++)
                arg_types[ix - 1] = VALUE_TYPE (argvec[ix]);

              (void) find_overload_match (arg_types, nargs, tstr,
                                     1 /* method */ , 0 /* strict match */ ,
                                          &arg2 /* the object */ , NULL,
                                          &valp, NULL, &static_memfuncp);


              argvec[1] = arg2; /* the ``this'' pointer */
              argvec[0] = valp; /* use the method found after overload resolution */
            }
          else
            /* Non-C++ case -- or no overload resolution */
            {
              struct value *temp = arg2;
              argvec[0] = value_struct_elt (&temp, argvec + 1, tstr,
                                            &static_memfuncp,
                                            op == STRUCTOP_STRUCT
                                       ? "structure" : "structure pointer");
              /* value_struct_elt updates temp with the correct value
                 of the ``this'' pointer if necessary, so modify argvec[1] to
                 reflect any ``this'' changes.  */
              arg2 = value_from_longest (lookup_pointer_type(VALUE_TYPE (temp)),
                             VALUE_ADDRESS (temp) + VALUE_OFFSET (temp)
                             + VALUE_EMBEDDED_OFFSET (temp));
              argvec[1] = arg2; /* the ``this'' pointer */
            }

          if (static_memfuncp)
            {
              argvec[1] = argvec[0];
              nargs--;
              argvec++;
            }
        }
      else if (op == STRUCTOP_MEMBER || op == STRUCTOP_MPTR)
        {
          argvec[1] = arg2;
          argvec[0] = arg1;
        }
      else if (op == OP_VAR_VALUE)
        {
          /* Non-member function being called */
          /* fn: This can only be done for C++ functions.  A C-style function
             in a C++ program, for instance, does not have the fields that 
             are expected here */

          if (overload_resolution && (exp->language_defn->la_language == language_cplus))
            {
              /* Language is C++, do some overload resolution before evaluation */
              struct symbol *symp;

              /* Prepare list of argument types for overload resolution */
              arg_types = (struct type **) alloca (nargs * (sizeof (struct type *)));
              for (ix = 1; ix <= nargs; ix++)
                arg_types[ix - 1] = VALUE_TYPE (argvec[ix]);

              (void) find_overload_match (arg_types, nargs, NULL /* no need for name */ ,
                                 0 /* not method */ , 0 /* strict match */ ,
                      NULL, exp->elts[save_pos1+2].symbol /* the function */ ,
                                          NULL, &symp, NULL);

              /* Now fix the expression being evaluated */
              exp->elts[save_pos1+2].symbol = symp;
              argvec[0] = evaluate_subexp_with_coercion (exp, &save_pos1, noside);
            }
          else
            {
              /* Not C++, or no overload resolution allowed */
              /* nothing to be done; argvec already correctly set up */
            }
        }
      else
        {
          /* It is probably a C-style function */
          /* nothing to be done; argvec already correctly set up */
        }

    do_call_it:

      if (noside == EVAL_SKIP)
        goto nosideret;
      if (argvec[0] == NULL)
        error ("Cannot evaluate function -- may be inlined");
      if (noside == EVAL_AVOID_SIDE_EFFECTS)
        {
          /* If the return type doesn't look like a function type, call an
             error.  This can happen if somebody tries to turn a variable into
             a function call. This is here because people often want to
             call, eg, strcmp, which gdb doesn't know is a function.  If
             gdb isn't asked for it's opinion (ie. through "whatis"),
             it won't offer it. */

          struct type *ftype =
          TYPE_TARGET_TYPE (VALUE_TYPE (argvec[0]));

          if (ftype)
            return allocate_value (TYPE_TARGET_TYPE (VALUE_TYPE (argvec[0])));
          else
            error ("Expression of type other than \"Function returning ...\" used as function");
        }
      return call_function_by_hand (argvec[0], nargs, argvec + 1);
      /* pai: FIXME save value from call_function_by_hand, then adjust pc by adjust_fn_pc if +ve  */

    case OP_F77_UNDETERMINED_ARGLIST:

      /* Remember that in F77, functions, substring ops and 
         array subscript operations cannot be disambiguated 
         at parse time.  We have made all array subscript operations, 
         substring operations as well as function calls  come here 
         and we now have to discover what the heck this thing actually was.  
         If it is a function, we process just as if we got an OP_FUNCALL. */

      nargs = longest_to_int (exp->elts[pc + 1].longconst);
      (*pos) += 2;

      /* First determine the type code we are dealing with.  */
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      type = check_typedef (VALUE_TYPE (arg1));
      code = TYPE_CODE (type);

      switch (code)
        {
        case TYPE_CODE_ARRAY:
          goto multi_f77_subscript;

        case TYPE_CODE_STRING:
          goto op_f77_substr;

        case TYPE_CODE_PTR:
        case TYPE_CODE_FUNC:
          /* It's a function call. */
          /* Allocate arg vector, including space for the function to be
             called in argvec[0] and a terminating NULL */
          argvec = (struct value **) alloca (sizeof (struct value *) * (nargs + 2));
          argvec[0] = arg1;
          tem = 1;
          for (; tem <= nargs; tem++)
            argvec[tem] = evaluate_subexp_with_coercion (exp, pos, noside);
          argvec[tem] = 0;      /* signal end of arglist */
          goto do_call_it;

        default:
          error ("Cannot perform substring on this type");
        }

    op_f77_substr:
      /* We have a substring operation on our hands here, 
         let us get the string we will be dealing with */

      /* Now evaluate the 'from' and 'to' */

      arg2 = evaluate_subexp_with_coercion (exp, pos, noside);

      if (nargs < 2)
        return value_subscript (arg1, arg2);

      arg3 = evaluate_subexp_with_coercion (exp, pos, noside);

      if (noside == EVAL_SKIP)
        goto nosideret;

      tem2 = value_as_long (arg2);
      tem3 = value_as_long (arg3);

      return value_slice (arg1, tem2, tem3 - tem2 + 1);

    case OP_COMPLEX:
      /* We have a complex number, There should be 2 floating 
         point numbers that compose it */
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);

      return value_literal_complex (arg1, arg2, builtin_type_f_complex_s16);

    case STRUCTOP_STRUCT:
      tem = longest_to_int (exp->elts[pc + 1].longconst);
      (*pos) += 3 + BYTES_TO_EXP_ELEM (tem + 1);
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (noside == EVAL_AVOID_SIDE_EFFECTS)
        return value_zero (lookup_struct_elt_type (VALUE_TYPE (arg1),
                                                   &exp->elts[pc + 2].string,
                                                   0),
                           lval_memory);
      else
        {
          struct value *temp = arg1;
          return value_struct_elt (&temp, NULL, &exp->elts[pc + 2].string,
                                   NULL, "structure");
        }

    case STRUCTOP_PTR:
      tem = longest_to_int (exp->elts[pc + 1].longconst);
      (*pos) += 3 + BYTES_TO_EXP_ELEM (tem + 1);
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;

      /* JYG: if print object is on we need to replace the base type
         with rtti type in order to continue on with successful
         lookup of member / method only available in the rtti type. */
      {
        struct type *type = VALUE_TYPE (arg1);
        struct type *real_type;
        int full, top, using_enc;
        
        if (objectprint && TYPE_TARGET_TYPE(type) &&
            (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
          {
            real_type = value_rtti_target_type (arg1, &full, &top, &using_enc);
            if (real_type)
              {
                if (TYPE_CODE (type) == TYPE_CODE_PTR)
                  real_type = lookup_pointer_type (real_type);
                else
                  real_type = lookup_reference_type (real_type);

                arg1 = value_cast (real_type, arg1);
              }
          }
      }

      if (noside == EVAL_AVOID_SIDE_EFFECTS)
        return value_zero (lookup_struct_elt_type (VALUE_TYPE (arg1),
                                                   &exp->elts[pc + 2].string,
                                                   0),
                           lval_memory);
      else
        {
          struct value *temp = arg1;
          return value_struct_elt (&temp, NULL, &exp->elts[pc + 2].string,
                                   NULL, "structure pointer");
        }

    case STRUCTOP_MEMBER:
      arg1 = evaluate_subexp_for_address (exp, pos, noside);
      arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);

      /* With HP aCC, pointers to methods do not point to the function code */
      if (hp_som_som_object_present &&
          (TYPE_CODE (VALUE_TYPE (arg2)) == TYPE_CODE_PTR) &&
      (TYPE_CODE (TYPE_TARGET_TYPE (VALUE_TYPE (arg2))) == TYPE_CODE_METHOD))
        error ("Pointers to methods not supported with HP aCC");        /* 1997-08-19 */

      mem_offset = value_as_long (arg2);
      goto handle_pointer_to_member;

    case STRUCTOP_MPTR:
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);

      /* With HP aCC, pointers to methods do not point to the function code */
      if (hp_som_som_object_present &&
          (TYPE_CODE (VALUE_TYPE (arg2)) == TYPE_CODE_PTR) &&
      (TYPE_CODE (TYPE_TARGET_TYPE (VALUE_TYPE (arg2))) == TYPE_CODE_METHOD))
        error ("Pointers to methods not supported with HP aCC");        /* 1997-08-19 */

      mem_offset = value_as_long (arg2);

    handle_pointer_to_member:
      /* HP aCC generates offsets that have bit #29 set; turn it off to get
         a real offset to the member. */
      if (hp_som_som_object_present)
        {
          if (!mem_offset)      /* no bias -> really null */
            error ("Attempted dereference of null pointer-to-member");
          mem_offset &= ~0x20000000;
        }
      if (noside == EVAL_SKIP)
        goto nosideret;
      type = check_typedef (VALUE_TYPE (arg2));
      if (TYPE_CODE (type) != TYPE_CODE_PTR)
        goto bad_pointer_to_member;
      type = check_typedef (TYPE_TARGET_TYPE (type));
      if (TYPE_CODE (type) == TYPE_CODE_METHOD)
        error ("not implemented: pointer-to-method in pointer-to-member construct");
      if (TYPE_CODE (type) != TYPE_CODE_MEMBER)
        goto bad_pointer_to_member;
      /* Now, convert these values to an address.  */
      arg1 = value_cast (lookup_pointer_type (TYPE_DOMAIN_TYPE (type)),
                         arg1);
      arg3 = value_from_pointer (lookup_pointer_type (TYPE_TARGET_TYPE (type)),
                                 value_as_long (arg1) + mem_offset);
      return value_ind (arg3);
    bad_pointer_to_member:
      error ("non-pointer-to-member value used in pointer-to-member construct");

    case BINOP_CONCAT:
      arg1 = evaluate_subexp_with_coercion (exp, pos, noside);
      arg2 = evaluate_subexp_with_coercion (exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (binop_user_defined_p (op, arg1, arg2))
        return value_x_binop (arg1, arg2, op, OP_NULL, noside);
      else
        return value_concat (arg1, arg2);

    case BINOP_ASSIGN:
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      arg2 = evaluate_subexp (VALUE_TYPE (arg1), exp, pos, noside);

      /* Do special stuff for HP aCC pointers to members */
      if (hp_som_som_object_present)
        {
          /* 1997-08-19 Can't assign HP aCC pointers to methods. No details of
             the implementation yet; but the pointer appears to point to a code
             sequence (thunk) in memory -- in any case it is *not* the address
             of the function as it would be in a naive implementation. */
          if ((TYPE_CODE (VALUE_TYPE (arg1)) == TYPE_CODE_PTR) &&
              (TYPE_CODE (TYPE_TARGET_TYPE (VALUE_TYPE (arg1))) == TYPE_CODE_METHOD))
            error ("Assignment to pointers to methods not implemented with HP aCC");

          /* HP aCC pointers to data members require a constant bias */
          if ((TYPE_CODE (VALUE_TYPE (arg1)) == TYPE_CODE_PTR) &&
              (TYPE_CODE (TYPE_TARGET_TYPE (VALUE_TYPE (arg1))) == TYPE_CODE_MEMBER))
            {
              unsigned int *ptr = (unsigned int *) VALUE_CONTENTS (arg2);       /* forces evaluation */
              *ptr |= 0x20000000;       /* set 29th bit */
            }
        }

      if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
        return arg1;
      if (binop_user_defined_p (op, arg1, arg2))
        return value_x_binop (arg1, arg2, op, OP_NULL, noside);
      else
        return value_assign (arg1, arg2);

    case BINOP_ASSIGN_MODIFY:
      (*pos) += 2;
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      arg2 = evaluate_subexp (VALUE_TYPE (arg1), exp, pos, noside);
      if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
        return arg1;
      op = exp->elts[pc + 1].opcode;
      if (binop_user_defined_p (op, arg1, arg2))
        return value_x_binop (arg1, arg2, BINOP_ASSIGN_MODIFY, op, noside);
      else if (op == BINOP_ADD)
        arg2 = value_add (arg1, arg2);
      else if (op == BINOP_SUB)
        arg2 = value_sub (arg1, arg2);
      else
        arg2 = value_binop (arg1, arg2, op);
      return value_assign (arg1, arg2);

    case BINOP_ADD:
      arg1 = evaluate_subexp_with_coercion (exp, pos, noside);
      arg2 = evaluate_subexp_with_coercion (exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (binop_user_defined_p (op, arg1, arg2))
        return value_x_binop (arg1, arg2, op, OP_NULL, noside);
      else
        return value_add (arg1, arg2);

    case BINOP_SUB:
      arg1 = evaluate_subexp_with_coercion (exp, pos, noside);
      arg2 = evaluate_subexp_with_coercion (exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (binop_user_defined_p (op, arg1, arg2))
        return value_x_binop (arg1, arg2, op, OP_NULL, noside);
      else
        return value_sub (arg1, arg2);

    case BINOP_MUL:
    case BINOP_DIV:
    case BINOP_REM:
    case BINOP_MOD:
    case BINOP_LSH:
    case BINOP_RSH:
    case BINOP_BITWISE_AND:
    case BINOP_BITWISE_IOR:
    case BINOP_BITWISE_XOR:
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (binop_user_defined_p (op, arg1, arg2))
        return value_x_binop (arg1, arg2, op, OP_NULL, noside);
      else if (noside == EVAL_AVOID_SIDE_EFFECTS
               && (op == BINOP_DIV || op == BINOP_REM || op == BINOP_MOD))
        return value_zero (VALUE_TYPE (arg1), not_lval);
      else
        return value_binop (arg1, arg2, op);

    case BINOP_RANGE:
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      error ("':' operator used in invalid context");

    case BINOP_SUBSCRIPT:
      arg1 = evaluate_subexp_with_coercion (exp, pos, noside);
      arg2 = evaluate_subexp_with_coercion (exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (binop_user_defined_p (op, arg1, arg2))
        return value_x_binop (arg1, arg2, op, OP_NULL, noside);
      else
        {
          /* If the user attempts to subscript something that is not an
             array or pointer type (like a plain int variable for example),
             then report this as an error. */

          COERCE_REF (arg1);
          type = check_typedef (VALUE_TYPE (arg1));
          if (TYPE_CODE (type) != TYPE_CODE_ARRAY
              && TYPE_CODE (type) != TYPE_CODE_PTR)
            {
              if (TYPE_NAME (type))
                error ("cannot subscript something of type `%s'",
                       TYPE_NAME (type));
              else
                error ("cannot subscript requested type");
            }

          if (noside == EVAL_AVOID_SIDE_EFFECTS)
            return value_zero (TYPE_TARGET_TYPE (type), VALUE_LVAL (arg1));
          else
            return value_subscript (arg1, arg2);
        }

    case BINOP_IN:
      arg1 = evaluate_subexp_with_coercion (exp, pos, noside);
      arg2 = evaluate_subexp_with_coercion (exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      return value_in (arg1, arg2);

    case MULTI_SUBSCRIPT:
      (*pos) += 2;
      nargs = longest_to_int (exp->elts[pc + 1].longconst);
      arg1 = evaluate_subexp_with_coercion (exp, pos, noside);
      while (nargs-- > 0)
        {
          arg2 = evaluate_subexp_with_coercion (exp, pos, noside);
          /* FIXME:  EVAL_SKIP handling may not be correct. */
          if (noside == EVAL_SKIP)
            {
              if (nargs > 0)
                {
                  continue;
                }
              else
                {
                  goto nosideret;
                }
            }
          /* FIXME:  EVAL_AVOID_SIDE_EFFECTS handling may not be correct. */
          if (noside == EVAL_AVOID_SIDE_EFFECTS)
            {
              /* If the user attempts to subscript something that has no target
                 type (like a plain int variable for example), then report this
                 as an error. */

              type = TYPE_TARGET_TYPE (check_typedef (VALUE_TYPE (arg1)));
              if (type != NULL)
                {
                  arg1 = value_zero (type, VALUE_LVAL (arg1));
                  noside = EVAL_SKIP;
                  continue;
                }
              else
                {
                  error ("cannot subscript something of type `%s'",
                         TYPE_NAME (VALUE_TYPE (arg1)));
                }
            }

          if (binop_user_defined_p (op, arg1, arg2))
            {
              arg1 = value_x_binop (arg1, arg2, op, OP_NULL, noside);
            }
          else
            {
              arg1 = value_subscript (arg1, arg2);
            }
        }
      return (arg1);

    multi_f77_subscript:
      {
        int subscript_array[MAX_FORTRAN_DIMS + 1];      /* 1-based array of 
                                                           subscripts, max == 7 */
        int array_size_array[MAX_FORTRAN_DIMS + 1];
        int ndimensions = 1, i;
        struct type *tmp_type;
        int offset_item;        /* The array offset where the item lives */

        if (nargs > MAX_FORTRAN_DIMS)
          error ("Too many subscripts for F77 (%d Max)", MAX_FORTRAN_DIMS);

        tmp_type = check_typedef (VALUE_TYPE (arg1));
        ndimensions = calc_f77_array_dims (type);

        if (nargs != ndimensions)
          error ("Wrong number of subscripts");

        /* Now that we know we have a legal array subscript expression 
           let us actually find out where this element exists in the array. */

        offset_item = 0;
        for (i = 1; i <= nargs; i++)
          {
            /* Evaluate each subscript, It must be a legal integer in F77 */
            arg2 = evaluate_subexp_with_coercion (exp, pos, noside);

            /* Fill in the subscript and array size arrays */

            subscript_array[i] = value_as_long (arg2);

            retcode = f77_get_dynamic_upperbound (tmp_type, &upper);
            if (retcode == BOUND_FETCH_ERROR)
              error ("Cannot obtain dynamic upper bound");

            retcode = f77_get_dynamic_lowerbound (tmp_type, &lower);
            if (retcode == BOUND_FETCH_ERROR)
              error ("Cannot obtain dynamic lower bound");

            array_size_array[i] = upper - lower + 1;

            /* Zero-normalize subscripts so that offsetting will work. */

            subscript_array[i] -= lower;

            /* If we are at the bottom of a multidimensional 
               array type then keep a ptr to the last ARRAY
               type around for use when calling value_subscript()
               below. This is done because we pretend to value_subscript
               that we actually have a one-dimensional array 
               of base element type that we apply a simple 
               offset to. */

            if (i < nargs)
              tmp_type = check_typedef (TYPE_TARGET_TYPE (tmp_type));
          }

        /* Now let us calculate the offset for this item */

        offset_item = subscript_array[ndimensions];

        for (i = ndimensions - 1; i >= 1; i--)
          offset_item =
            array_size_array[i] * offset_item + subscript_array[i];

        /* Construct a value node with the value of the offset */

        arg2 = value_from_longest (builtin_type_f_integer, offset_item);

        /* Let us now play a dirty trick: we will take arg1 
           which is a value node pointing to the topmost level
           of the multidimensional array-set and pretend
           that it is actually a array of the final element 
           type, this will ensure that value_subscript()
           returns the correct type value */

        VALUE_TYPE (arg1) = tmp_type;
        return value_ind (value_add (value_coerce_array (arg1), arg2));
      }

    case BINOP_LOGICAL_AND:
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      if (noside == EVAL_SKIP)
        {
          arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
          goto nosideret;
        }

      oldpos = *pos;
      arg2 = evaluate_subexp (NULL_TYPE, exp, pos, EVAL_AVOID_SIDE_EFFECTS);
      *pos = oldpos;

      if (binop_user_defined_p (op, arg1, arg2))
        {
          arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
          return value_x_binop (arg1, arg2, op, OP_NULL, noside);
        }
      else
        {
          tem = value_logical_not (arg1);
          arg2 = evaluate_subexp (NULL_TYPE, exp, pos,
                                  (tem ? EVAL_SKIP : noside));
          return value_from_longest (LA_BOOL_TYPE,
                             (LONGEST) (!tem && !value_logical_not (arg2)));
        }

    case BINOP_LOGICAL_OR:
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      if (noside == EVAL_SKIP)
        {
          arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
          goto nosideret;
        }

      oldpos = *pos;
      arg2 = evaluate_subexp (NULL_TYPE, exp, pos, EVAL_AVOID_SIDE_EFFECTS);
      *pos = oldpos;

      if (binop_user_defined_p (op, arg1, arg2))
        {
          arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
          return value_x_binop (arg1, arg2, op, OP_NULL, noside);
        }
      else
        {
          tem = value_logical_not (arg1);
          arg2 = evaluate_subexp (NULL_TYPE, exp, pos,
                                  (!tem ? EVAL_SKIP : noside));
          return value_from_longest (LA_BOOL_TYPE,
                             (LONGEST) (!tem || !value_logical_not (arg2)));
        }

    case BINOP_EQUAL:
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      arg2 = evaluate_subexp (VALUE_TYPE (arg1), exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (binop_user_defined_p (op, arg1, arg2))
        {
          return value_x_binop (arg1, arg2, op, OP_NULL, noside);
        }
      else
        {
          tem = value_equal (arg1, arg2);
          return value_from_longest (LA_BOOL_TYPE, (LONGEST) tem);
        }

    case BINOP_NOTEQUAL:
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      arg2 = evaluate_subexp (VALUE_TYPE (arg1), exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (binop_user_defined_p (op, arg1, arg2))
        {
          return value_x_binop (arg1, arg2, op, OP_NULL, noside);
        }
      else
        {
          tem = value_equal (arg1, arg2);
          return value_from_longest (LA_BOOL_TYPE, (LONGEST) ! tem);
        }

    case BINOP_LESS:
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      arg2 = evaluate_subexp (VALUE_TYPE (arg1), exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (binop_user_defined_p (op, arg1, arg2))
        {
          return value_x_binop (arg1, arg2, op, OP_NULL, noside);
        }
      else
        {
          tem = value_less (arg1, arg2);
          return value_from_longest (LA_BOOL_TYPE, (LONGEST) tem);
        }

    case BINOP_GTR:
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      arg2 = evaluate_subexp (VALUE_TYPE (arg1), exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (binop_user_defined_p (op, arg1, arg2))
        {
          return value_x_binop (arg1, arg2, op, OP_NULL, noside);
        }
      else
        {
          tem = value_less (arg2, arg1);
          return value_from_longest (LA_BOOL_TYPE, (LONGEST) tem);
        }

    case BINOP_GEQ:
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      arg2 = evaluate_subexp (VALUE_TYPE (arg1), exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (binop_user_defined_p (op, arg1, arg2))
        {
          return value_x_binop (arg1, arg2, op, OP_NULL, noside);
        }
      else
        {
          tem = value_less (arg2, arg1) || value_equal (arg1, arg2);
          return value_from_longest (LA_BOOL_TYPE, (LONGEST) tem);
        }

    case BINOP_LEQ:
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      arg2 = evaluate_subexp (VALUE_TYPE (arg1), exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (binop_user_defined_p (op, arg1, arg2))
        {
          return value_x_binop (arg1, arg2, op, OP_NULL, noside);
        }
      else
        {
          tem = value_less (arg1, arg2) || value_equal (arg1, arg2);
          return value_from_longest (LA_BOOL_TYPE, (LONGEST) tem);
        }

    case BINOP_REPEAT:
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      arg2 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      type = check_typedef (VALUE_TYPE (arg2));
      if (TYPE_CODE (type) != TYPE_CODE_INT)
        error ("Non-integral right operand for \"@\" operator.");
      if (noside == EVAL_AVOID_SIDE_EFFECTS)
        {
          return allocate_repeat_value (VALUE_TYPE (arg1),
                                     longest_to_int (value_as_long (arg2)));
        }
      else
        return value_repeat (arg1, longest_to_int (value_as_long (arg2)));

    case BINOP_COMMA:
      evaluate_subexp (NULL_TYPE, exp, pos, noside);
      return evaluate_subexp (NULL_TYPE, exp, pos, noside);

    case UNOP_NEG:
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (unop_user_defined_p (op, arg1))
        return value_x_unop (arg1, op, noside);
      else
        return value_neg (arg1);

    case UNOP_COMPLEMENT:
      /* C++: check for and handle destructor names.  */
      op = exp->elts[*pos].opcode;

      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (unop_user_defined_p (UNOP_COMPLEMENT, arg1))
        return value_x_unop (arg1, UNOP_COMPLEMENT, noside);
      else
        return value_complement (arg1);

    case UNOP_LOGICAL_NOT:
      arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (unop_user_defined_p (op, arg1))
        return value_x_unop (arg1, op, noside);
      else
        return value_from_longest (LA_BOOL_TYPE,
                                   (LONGEST) value_logical_not (arg1));

    case UNOP_IND:
      if (expect_type && TYPE_CODE (expect_type) == TYPE_CODE_PTR)
        expect_type = TYPE_TARGET_TYPE (check_typedef (expect_type));
      arg1 = evaluate_subexp (expect_type, exp, pos, noside);
      if ((TYPE_TARGET_TYPE (VALUE_TYPE (arg1))) &&
          ((TYPE_CODE (TYPE_TARGET_TYPE (VALUE_TYPE (arg1))) == TYPE_CODE_METHOD) ||
           (TYPE_CODE (TYPE_TARGET_TYPE (VALUE_TYPE (arg1))) == TYPE_CODE_MEMBER)))
        error ("Attempt to dereference pointer to member without an object");
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (unop_user_defined_p (op, arg1))
        return value_x_unop (arg1, op, noside);
      else if (noside == EVAL_AVOID_SIDE_EFFECTS)
        {
          type = check_typedef (VALUE_TYPE (arg1));
          if (TYPE_CODE (type) == TYPE_CODE_PTR
              || TYPE_CODE (type) == TYPE_CODE_REF
          /* In C you can dereference an array to get the 1st elt.  */
              || TYPE_CODE (type) == TYPE_CODE_ARRAY
            )
            return value_zero (TYPE_TARGET_TYPE (type),
                               lval_memory);
          else if (TYPE_CODE (type) == TYPE_CODE_INT)
            /* GDB allows dereferencing an int.  */
            return value_zero (builtin_type_int, lval_memory);
          else
            error ("Attempt to take contents of a non-pointer value.");
        }
      return value_ind (arg1);

    case UNOP_ADDR:
      /* C++: check for and handle pointer to members.  */

      op = exp->elts[*pos].opcode;

      if (noside == EVAL_SKIP)
        {
          if (op == OP_SCOPE)
            {
              int temm = longest_to_int (exp->elts[pc + 3].longconst);
              (*pos) += 3 + BYTES_TO_EXP_ELEM (temm + 1);
            }
          else
            evaluate_subexp (NULL_TYPE, exp, pos, EVAL_SKIP);
          goto nosideret;
        }
      else
        {
          struct value *retvalp = evaluate_subexp_for_address (exp, pos, noside);
          /* If HP aCC object, use bias for pointers to members */
          if (hp_som_som_object_present &&
              (TYPE_CODE (VALUE_TYPE (retvalp)) == TYPE_CODE_PTR) &&
              (TYPE_CODE (TYPE_TARGET_TYPE (VALUE_TYPE (retvalp))) == TYPE_CODE_MEMBER))
            {
              unsigned int *ptr = (unsigned int *) VALUE_CONTENTS (retvalp);    /* forces evaluation */
              *ptr |= 0x20000000;       /* set 29th bit */
            }
          return retvalp;
        }

    case UNOP_SIZEOF:
      if (noside == EVAL_SKIP)
        {
          evaluate_subexp (NULL_TYPE, exp, pos, EVAL_SKIP);
          goto nosideret;
        }
      return evaluate_subexp_for_sizeof (exp, pos);

    case UNOP_CAST:
      (*pos) += 2;
      type = exp->elts[pc + 1].type;
      arg1 = evaluate_subexp (type, exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (type != VALUE_TYPE (arg1))
        arg1 = value_cast (type, arg1);
      return arg1;

    case UNOP_MEMVAL:
      (*pos) += 2;
      arg1 = evaluate_subexp (expect_type, exp, pos, noside);
      if (noside == EVAL_SKIP)
        goto nosideret;
      if (noside == EVAL_AVOID_SIDE_EFFECTS)
        return value_zero (exp->elts[pc + 1].type, lval_memory);
      else
        return value_at_lazy (exp->elts[pc + 1].type,
                              value_as_address (arg1),
                              NULL);

    case UNOP_PREINCREMENT:
      arg1 = evaluate_subexp (expect_type, exp, pos, noside);
      if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
        return arg1;
      else if (unop_user_defined_p (op, arg1))
        {
          return value_x_unop (arg1, op, noside);
        }
      else
        {
          arg2 = value_add (arg1, value_from_longest (builtin_type_char,
                                                      (LONGEST) 1));
          return value_assign (arg1, arg2);
        }

    case UNOP_PREDECREMENT:
      arg1 = evaluate_subexp (expect_type, exp, pos, noside);
      if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
        return arg1;
      else if (unop_user_defined_p (op, arg1))
        {
          return value_x_unop (arg1, op, noside);
        }
      else
        {
          arg2 = value_sub (arg1, value_from_longest (builtin_type_char,
                                                      (LONGEST) 1));
          return value_assign (arg1, arg2);
        }

    case UNOP_POSTINCREMENT:
      arg1 = evaluate_subexp (expect_type, exp, pos, noside);
      if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
        return arg1;
      else if (unop_user_defined_p (op, arg1))
        {
          return value_x_unop (arg1, op, noside);
        }
      else
        {
          arg2 = value_add (arg1, value_from_longest (builtin_type_char,
                                                      (LONGEST) 1));
          value_assign (arg1, arg2);
          return arg1;
        }

    case UNOP_POSTDECREMENT:
      arg1 = evaluate_subexp (expect_type, exp, pos, noside);
      if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
        return arg1;
      else if (unop_user_defined_p (op, arg1))
        {
          return value_x_unop (arg1, op, noside);
        }
      else
        {
          arg2 = value_sub (arg1, value_from_longest (builtin_type_char,
                                                      (LONGEST) 1));
          value_assign (arg1, arg2);
          return arg1;
        }

    case OP_THIS:
      (*pos) += 1;
      return value_of_this (1);

    case OP_OBJC_SELF:
      (*pos) += 1;
      return value_of_local ("self", 1);

    case OP_TYPE:
      error ("Attempt to use a type name as an expression");

    default:
      /* Removing this case and compiling with gcc -Wall reveals that
         a lot of cases are hitting this case.  Some of these should
         probably be removed from expression.h; others are legitimate
         expressions which are (apparently) not fully implemented.

         If there are any cases landing here which mean a user error,
         then they should be separate cases, with more descriptive
         error messages.  */

      error ("\
GDB does not (yet) know how to evaluate that kind of expression");
    }

nosideret:
  return value_from_longest (builtin_type_long, (LONGEST) 1);
}
\f
/* Evaluate a subexpression of EXP, at index *POS,
   and return the address of that subexpression.
   Advance *POS over the subexpression.
   If the subexpression isn't an lvalue, get an error.
   NOSIDE may be EVAL_AVOID_SIDE_EFFECTS;
   then only the type of the result need be correct.  */

static struct value *
evaluate_subexp_for_address (struct expression *exp, int *pos,
                             enum noside noside)
{
  enum exp_opcode op;
  int pc;
  struct symbol *var;

  pc = (*pos);
  op = exp->elts[pc].opcode;

  switch (op)
    {
    case UNOP_IND:
      (*pos)++;
      return evaluate_subexp (NULL_TYPE, exp, pos, noside);

    case UNOP_MEMVAL:
      (*pos) += 3;
      return value_cast (lookup_pointer_type (exp->elts[pc + 1].type),
                         evaluate_subexp (NULL_TYPE, exp, pos, noside));

    case OP_VAR_VALUE:
      var = exp->elts[pc + 2].symbol;

      /* C++: The "address" of a reference should yield the address
       * of the object pointed to. Let value_addr() deal with it. */
      if (TYPE_CODE (SYMBOL_TYPE (var)) == TYPE_CODE_REF)
        goto default_case;

      (*pos) += 4;
      if (noside == EVAL_AVOID_SIDE_EFFECTS)
        {
          struct type *type =
          lookup_pointer_type (SYMBOL_TYPE (var));
          enum address_class sym_class = SYMBOL_CLASS (var);

          if (sym_class == LOC_CONST
              || sym_class == LOC_CONST_BYTES
              || sym_class == LOC_REGISTER
              || sym_class == LOC_REGPARM)
            error ("Attempt to take address of register or constant.");

          return
            value_zero (type, not_lval);
        }
      else
        return
          locate_var_value
          (var,
           block_innermost_frame (exp->elts[pc + 1].block));

    default:
    default_case:
      if (noside == EVAL_AVOID_SIDE_EFFECTS)
        {
          struct value *x = evaluate_subexp (NULL_TYPE, exp, pos, noside);
          if (VALUE_LVAL (x) == lval_memory)
            return value_zero (lookup_pointer_type (VALUE_TYPE (x)),
                               not_lval);
          else
            error ("Attempt to take address of non-lval");
        }
      return value_addr (evaluate_subexp (NULL_TYPE, exp, pos, noside));
    }
}

/* Evaluate like `evaluate_subexp' except coercing arrays to pointers.
   When used in contexts where arrays will be coerced anyway, this is
   equivalent to `evaluate_subexp' but much faster because it avoids
   actually fetching array contents (perhaps obsolete now that we have
   VALUE_LAZY).

   Note that we currently only do the coercion for C expressions, where
   arrays are zero based and the coercion is correct.  For other languages,
   with nonzero based arrays, coercion loses.  Use CAST_IS_CONVERSION
   to decide if coercion is appropriate.

 */

struct value *
evaluate_subexp_with_coercion (struct expression *exp,
                               int *pos, enum noside noside)
{
  enum exp_opcode op;
  int pc;
  struct value *val;
  struct symbol *var;

  pc = (*pos);
  op = exp->elts[pc].opcode;

  switch (op)
    {
    case OP_VAR_VALUE:
      var = exp->elts[pc + 2].symbol;
      if (TYPE_CODE (check_typedef (SYMBOL_TYPE (var))) == TYPE_CODE_ARRAY
          && CAST_IS_CONVERSION)
        {
          (*pos) += 4;
          val =
            locate_var_value
            (var, block_innermost_frame (exp->elts[pc + 1].block));
          return value_cast (lookup_pointer_type (TYPE_TARGET_TYPE (check_typedef (SYMBOL_TYPE (var)))),
                             val);
        }
      /* FALLTHROUGH */

    default:
      return evaluate_subexp (NULL_TYPE, exp, pos, noside);
    }
}

/* Evaluate a subexpression of EXP, at index *POS,
   and return a value for the size of that subexpression.
   Advance *POS over the subexpression.  */

static struct value *
evaluate_subexp_for_sizeof (struct expression *exp, int *pos)
{
  enum exp_opcode op;
  int pc;
  struct type *type;
  struct value *val;

  pc = (*pos);
  op = exp->elts[pc].opcode;

  switch (op)
    {
      /* This case is handled specially
         so that we avoid creating a value for the result type.
         If the result type is very big, it's desirable not to
         create a value unnecessarily.  */
    case UNOP_IND:
      (*pos)++;
      val = evaluate_subexp (NULL_TYPE, exp, pos, EVAL_AVOID_SIDE_EFFECTS);
      type = check_typedef (VALUE_TYPE (val));
      if (TYPE_CODE (type) != TYPE_CODE_PTR
          && TYPE_CODE (type) != TYPE_CODE_REF
          && TYPE_CODE (type) != TYPE_CODE_ARRAY)
        error ("Attempt to take contents of a non-pointer value.");
      type = check_typedef (TYPE_TARGET_TYPE (type));
      return value_from_longest (builtin_type_int, (LONGEST)
                                 TYPE_LENGTH (type));

    case UNOP_MEMVAL:
      (*pos) += 3;
      type = check_typedef (exp->elts[pc + 1].type);
      return value_from_longest (builtin_type_int,
                                 (LONGEST) TYPE_LENGTH (type));

    case OP_VAR_VALUE:
      (*pos) += 4;
      type = check_typedef (SYMBOL_TYPE (exp->elts[pc + 2].symbol));
      return
        value_from_longest (builtin_type_int, (LONGEST) TYPE_LENGTH (type));

    default:
      val = evaluate_subexp (NULL_TYPE, exp, pos, EVAL_AVOID_SIDE_EFFECTS);
      return value_from_longest (builtin_type_int,
                                 (LONGEST) TYPE_LENGTH (VALUE_TYPE (val)));
    }
}

/* Parse a type expression in the string [P..P+LENGTH). */

struct type *
parse_and_eval_type (char *p, int length)
{
  char *tmp = (char *) alloca (length + 4);
  struct expression *expr;
  tmp[0] = '(';
  memcpy (tmp + 1, p, length);
  tmp[length + 1] = ')';
  tmp[length + 2] = '0';
  tmp[length + 3] = '\0';
  expr = parse_expression (tmp);
  if (expr->elts[0].opcode != UNOP_CAST)
    error ("Internal error in eval_type.");
  return expr->elts[1].type;
}

int
calc_f77_array_dims (struct type *array_type)
{
  int ndimen = 1;
  struct type *tmp_type;

  if ((TYPE_CODE (array_type) != TYPE_CODE_ARRAY))
    error ("Can't get dimensions for a non-array type");

  tmp_type = array_type;

  while ((tmp_type = TYPE_TARGET_TYPE (tmp_type)))
    {
      if (TYPE_CODE (tmp_type) == TYPE_CODE_ARRAY)
        ++ndimen;
    }
  return ndimen;
}