* gdbtypes.c (make_pointer_type, make_reference_type,

[thirdparty/binutils-gdb.git] / gdb / valops.c

/* Perform non-arithmetic operations on values, for GDB.

   Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
   1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
   2008, 2009 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 3 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, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "symtab.h"
#include "gdbtypes.h"
#include "value.h"
#include "frame.h"
#include "inferior.h"
#include "gdbcore.h"
#include "target.h"
#include "demangle.h"
#include "language.h"
#include "gdbcmd.h"
#include "regcache.h"
#include "cp-abi.h"
#include "block.h"
#include "infcall.h"
#include "dictionary.h"
#include "cp-support.h"
#include "dfp.h"
#include "user-regs.h"

#include <errno.h>
#include "gdb_string.h"
#include "gdb_assert.h"
#include "cp-support.h"
#include "observer.h"
#include "objfiles.h"
#include "symtab.h"

extern int overload_debug;
/* Local functions.  */

static int typecmp (int staticp, int varargs, int nargs,
                    struct field t1[], struct value *t2[]);

static struct value *search_struct_field (char *, struct value *, 
                                          int, struct type *, int);

static struct value *search_struct_method (char *, struct value **,
                                       struct value **,
                                       int, int *, struct type *);

static int find_oload_champ_namespace (struct type **, int,
                                       const char *, const char *,
                                       struct symbol ***,
                                       struct badness_vector **);

static
int find_oload_champ_namespace_loop (struct type **, int,
                                     const char *, const char *,
                                     int, struct symbol ***,
                                     struct badness_vector **, int *);

static int find_oload_champ (struct type **, int, int, int,
                             struct fn_field *, struct symbol **,
                             struct badness_vector **);

static int oload_method_static (int, struct fn_field *, int);

enum oload_classification { STANDARD, NON_STANDARD, INCOMPATIBLE };

static enum
oload_classification classify_oload_match (struct badness_vector *,
                                           int, int);

static struct value *value_struct_elt_for_reference (struct type *,
                                                     int, struct type *,
                                                     char *,
                                                     struct type *,
                                                     int, enum noside);

static struct value *value_namespace_elt (const struct type *,
                                          char *, int , enum noside);

static struct value *value_maybe_namespace_elt (const struct type *,
                                                char *, int,
                                                enum noside);

static CORE_ADDR allocate_space_in_inferior (int);

static struct value *cast_into_complex (struct type *, struct value *);

static struct fn_field *find_method_list (struct value **, char *,
                                          int, struct type *, int *,
                                          struct type **, int *);

void _initialize_valops (void);

#if 0
/* Flag for whether we want to abandon failed expression evals by
   default.  */

static int auto_abandon = 0;
#endif

int overload_resolution = 0;
static void
show_overload_resolution (struct ui_file *file, int from_tty,
                          struct cmd_list_element *c, 
                          const char *value)
{
  fprintf_filtered (file, _("\
Overload resolution in evaluating C++ functions is %s.\n"),
                    value);
}

/* Find the address of function name NAME in the inferior.  If OBJF_P
   is non-NULL, *OBJF_P will be set to the OBJFILE where the function
   is defined.  */

struct value *
find_function_in_inferior (const char *name, struct objfile **objf_p)
{
  struct symbol *sym;
  sym = lookup_symbol (name, 0, VAR_DOMAIN, 0);
  if (sym != NULL)
    {
      if (SYMBOL_CLASS (sym) != LOC_BLOCK)
        {
          error (_("\"%s\" exists in this program but is not a function."),
                 name);
        }

      if (objf_p)
        *objf_p = SYMBOL_SYMTAB (sym)->objfile;

      return value_of_variable (sym, NULL);
    }
  else
    {
      struct minimal_symbol *msymbol = 
        lookup_minimal_symbol (name, NULL, NULL);
      if (msymbol != NULL)
        {
          struct objfile *objfile = msymbol_objfile (msymbol);
          struct gdbarch *gdbarch = get_objfile_arch (objfile);

          struct type *type;
          CORE_ADDR maddr;
          type = lookup_pointer_type (builtin_type (gdbarch)->builtin_char);
          type = lookup_function_type (type);
          type = lookup_pointer_type (type);
          maddr = SYMBOL_VALUE_ADDRESS (msymbol);

          if (objf_p)
            *objf_p = objfile;

          return value_from_pointer (type, maddr);
        }
      else
        {
          if (!target_has_execution)
            error (_("evaluation of this expression requires the target program to be active"));
          else
            error (_("evaluation of this expression requires the program to have a function \"%s\"."), name);
        }
    }
}

/* Allocate NBYTES of space in the inferior using the inferior's
   malloc and return a value that is a pointer to the allocated
   space.  */

struct value *
value_allocate_space_in_inferior (int len)
{
  struct objfile *objf;
  struct value *val = find_function_in_inferior ("malloc", &objf);
  struct gdbarch *gdbarch = get_objfile_arch (objf);
  struct value *blocklen;

  blocklen = value_from_longest (builtin_type (gdbarch)->builtin_int, len);
  val = call_function_by_hand (val, 1, &blocklen);
  if (value_logical_not (val))
    {
      if (!target_has_execution)
        error (_("No memory available to program now: you need to start the target first"));
      else
        error (_("No memory available to program: call to malloc failed"));
    }
  return val;
}

static CORE_ADDR
allocate_space_in_inferior (int len)
{
  return value_as_long (value_allocate_space_in_inferior (len));
}

/* Cast struct value VAL to type TYPE and return as a value.
   Both type and val must be of TYPE_CODE_STRUCT or TYPE_CODE_UNION
   for this to work.  Typedef to one of the codes is permitted.
   Returns NULL if the cast is neither an upcast nor a downcast.  */

static struct value *
value_cast_structs (struct type *type, struct value *v2)
{
  struct type *t1;
  struct type *t2;
  struct value *v;

  gdb_assert (type != NULL && v2 != NULL);

  t1 = check_typedef (type);
  t2 = check_typedef (value_type (v2));

  /* Check preconditions.  */
  gdb_assert ((TYPE_CODE (t1) == TYPE_CODE_STRUCT
               || TYPE_CODE (t1) == TYPE_CODE_UNION)
              && !!"Precondition is that type is of STRUCT or UNION kind.");
  gdb_assert ((TYPE_CODE (t2) == TYPE_CODE_STRUCT
               || TYPE_CODE (t2) == TYPE_CODE_UNION)
              && !!"Precondition is that value is of STRUCT or UNION kind");

  /* Upcasting: look in the type of the source to see if it contains the
     type of the target as a superclass.  If so, we'll need to
     offset the pointer rather than just change its type.  */
  if (TYPE_NAME (t1) != NULL)
    {
      v = search_struct_field (type_name_no_tag (t1),
                               v2, 0, t2, 1);
      if (v)
        return v;
    }

  /* Downcasting: look in the type of the target to see if it contains the
     type of the source as a superclass.  If so, we'll need to
     offset the pointer rather than just change its type.
     FIXME: This fails silently with virtual inheritance.  */
  if (TYPE_NAME (t2) != NULL)
    {
      v = search_struct_field (type_name_no_tag (t2),
                               value_zero (t1, not_lval), 0, t1, 1);
      if (v)
        {
          /* Downcasting is possible (t1 is superclass of v2).  */
          CORE_ADDR addr2 = value_address (v2);
          addr2 -= value_address (v) + value_embedded_offset (v);
          return value_at (type, addr2);
        }
    }

  return NULL;
}

/* Cast one pointer or reference type to another.  Both TYPE and
   the type of ARG2 should be pointer types, or else both should be
   reference types.  Returns the new pointer or reference.  */

struct value *
value_cast_pointers (struct type *type, struct value *arg2)
{
  struct type *type1 = check_typedef (type);
  struct type *type2 = check_typedef (value_type (arg2));
  struct type *t1 = check_typedef (TYPE_TARGET_TYPE (type));
  struct type *t2 = check_typedef (TYPE_TARGET_TYPE (type2));

  if (TYPE_CODE (t1) == TYPE_CODE_STRUCT
      && TYPE_CODE (t2) == TYPE_CODE_STRUCT
      && !value_logical_not (arg2))
    {
      struct value *v2;

      if (TYPE_CODE (type2) == TYPE_CODE_REF)
        v2 = coerce_ref (arg2);
      else
        v2 = value_ind (arg2);
      gdb_assert (TYPE_CODE (check_typedef (value_type (v2))) == TYPE_CODE_STRUCT
                  && !!"Why did coercion fail?");
      v2 = value_cast_structs (t1, v2);
      /* At this point we have what we can have, un-dereference if needed.  */
      if (v2)
        {
          struct value *v = value_addr (v2);
          deprecated_set_value_type (v, type);
          return v;
        }
   }

  /* No superclass found, just change the pointer type.  */
  arg2 = value_copy (arg2);
  deprecated_set_value_type (arg2, type);
  arg2 = value_change_enclosing_type (arg2, type);
  set_value_pointed_to_offset (arg2, 0);        /* pai: chk_val */
  return arg2;
}

/* Cast value ARG2 to type TYPE and return as a value.
   More general than a C cast: accepts any two types of the same length,
   and if ARG2 is an lvalue it can be cast into anything at all.  */
/* In C++, casts may change pointer or object representations.  */

struct value *
value_cast (struct type *type, struct value *arg2)
{
  enum type_code code1;
  enum type_code code2;
  int scalar;
  struct type *type2;

  int convert_to_boolean = 0;

  if (value_type (arg2) == type)
    return arg2;

  code1 = TYPE_CODE (check_typedef (type));

  /* Check if we are casting struct reference to struct reference.  */
  if (code1 == TYPE_CODE_REF)
    {
      /* We dereference type; then we recurse and finally
         we generate value of the given reference. Nothing wrong with 
         that.  */
      struct type *t1 = check_typedef (type);
      struct type *dereftype = check_typedef (TYPE_TARGET_TYPE (t1));
      struct value *val =  value_cast (dereftype, arg2);
      return value_ref (val); 
    }

  code2 = TYPE_CODE (check_typedef (value_type (arg2)));

  if (code2 == TYPE_CODE_REF)
    /* We deref the value and then do the cast.  */
    return value_cast (type, coerce_ref (arg2)); 

  CHECK_TYPEDEF (type);
  code1 = TYPE_CODE (type);
  arg2 = coerce_ref (arg2);
  type2 = check_typedef (value_type (arg2));

  /* You can't cast to a reference type.  See value_cast_pointers
     instead.  */
  gdb_assert (code1 != TYPE_CODE_REF);

  /* A cast to an undetermined-length array_type, such as 
     (TYPE [])OBJECT, is treated like a cast to (TYPE [N])OBJECT,
     where N is sizeof(OBJECT)/sizeof(TYPE).  */
  if (code1 == TYPE_CODE_ARRAY)
    {
      struct type *element_type = TYPE_TARGET_TYPE (type);
      unsigned element_length = TYPE_LENGTH (check_typedef (element_type));
      if (element_length > 0 && TYPE_ARRAY_UPPER_BOUND_IS_UNDEFINED (type))
        {
          struct type *range_type = TYPE_INDEX_TYPE (type);
          int val_length = TYPE_LENGTH (type2);
          LONGEST low_bound, high_bound, new_length;
          if (get_discrete_bounds (range_type, &low_bound, &high_bound) < 0)
            low_bound = 0, high_bound = 0;
          new_length = val_length / element_length;
          if (val_length % element_length != 0)
            warning (_("array element type size does not divide object size in cast"));
          /* FIXME-type-allocation: need a way to free this type when
             we are done with it.  */
          range_type = create_range_type ((struct type *) NULL,
                                          TYPE_TARGET_TYPE (range_type),
                                          low_bound,
                                          new_length + low_bound - 1);
          deprecated_set_value_type (arg2, 
                                     create_array_type ((struct type *) NULL,
                                                        element_type, 
                                                        range_type));
          return arg2;
        }
    }

  if (current_language->c_style_arrays
      && TYPE_CODE (type2) == TYPE_CODE_ARRAY)
    arg2 = value_coerce_array (arg2);

  if (TYPE_CODE (type2) == TYPE_CODE_FUNC)
    arg2 = value_coerce_function (arg2);

  type2 = check_typedef (value_type (arg2));
  code2 = TYPE_CODE (type2);

  if (code1 == TYPE_CODE_COMPLEX)
    return cast_into_complex (type, arg2);
  if (code1 == TYPE_CODE_BOOL)
    {
      code1 = TYPE_CODE_INT;
      convert_to_boolean = 1;
    }
  if (code1 == TYPE_CODE_CHAR)
    code1 = TYPE_CODE_INT;
  if (code2 == TYPE_CODE_BOOL || code2 == TYPE_CODE_CHAR)
    code2 = TYPE_CODE_INT;

  scalar = (code2 == TYPE_CODE_INT || code2 == TYPE_CODE_FLT
            || code2 == TYPE_CODE_DECFLOAT || code2 == TYPE_CODE_ENUM
            || code2 == TYPE_CODE_RANGE);

  if ((code1 == TYPE_CODE_STRUCT || code1 == TYPE_CODE_UNION)
      && (code2 == TYPE_CODE_STRUCT || code2 == TYPE_CODE_UNION)
      && TYPE_NAME (type) != 0)
    {
      struct value *v = value_cast_structs (type, arg2);
      if (v)
        return v;
    }

  if (code1 == TYPE_CODE_FLT && scalar)
    return value_from_double (type, value_as_double (arg2));
  else if (code1 == TYPE_CODE_DECFLOAT && scalar)
    {
      int dec_len = TYPE_LENGTH (type);
      gdb_byte dec[16];

      if (code2 == TYPE_CODE_FLT)
        decimal_from_floating (arg2, dec, dec_len);
      else if (code2 == TYPE_CODE_DECFLOAT)
        decimal_convert (value_contents (arg2), TYPE_LENGTH (type2),
                         dec, dec_len);
      else
        /* The only option left is an integral type.  */
        decimal_from_integral (arg2, dec, dec_len);

      return value_from_decfloat (type, dec);
    }
  else if ((code1 == TYPE_CODE_INT || code1 == TYPE_CODE_ENUM
            || code1 == TYPE_CODE_RANGE)
           && (scalar || code2 == TYPE_CODE_PTR
               || code2 == TYPE_CODE_MEMBERPTR))
    {
      LONGEST longest;

      /* When we cast pointers to integers, we mustn't use
         gdbarch_pointer_to_address to find the address the pointer
         represents, as value_as_long would.  GDB should evaluate
         expressions just as the compiler would --- and the compiler
         sees a cast as a simple reinterpretation of the pointer's
         bits.  */
      if (code2 == TYPE_CODE_PTR)
        longest = extract_unsigned_integer (value_contents (arg2),
                                            TYPE_LENGTH (type2));
      else
        longest = value_as_long (arg2);
      return value_from_longest (type, convert_to_boolean ?
                                 (LONGEST) (longest ? 1 : 0) : longest);
    }
  else if (code1 == TYPE_CODE_PTR && (code2 == TYPE_CODE_INT  
                                      || code2 == TYPE_CODE_ENUM 
                                      || code2 == TYPE_CODE_RANGE))
    {
      /* TYPE_LENGTH (type) is the length of a pointer, but we really
         want the length of an address! -- we are really dealing with
         addresses (i.e., gdb representations) not pointers (i.e.,
         target representations) here.

         This allows things like "print *(int *)0x01000234" to work
         without printing a misleading message -- which would
         otherwise occur when dealing with a target having two byte
         pointers and four byte addresses.  */

      int addr_bit = gdbarch_addr_bit (get_type_arch (type2));

      LONGEST longest = value_as_long (arg2);
      if (addr_bit < sizeof (LONGEST) * HOST_CHAR_BIT)
        {
          if (longest >= ((LONGEST) 1 << addr_bit)
              || longest <= -((LONGEST) 1 << addr_bit))
            warning (_("value truncated"));
        }
      return value_from_longest (type, longest);
    }
  else if (code1 == TYPE_CODE_METHODPTR && code2 == TYPE_CODE_INT
           && value_as_long (arg2) == 0)
    {
      struct value *result = allocate_value (type);
      cplus_make_method_ptr (type, value_contents_writeable (result), 0, 0);
      return result;
    }
  else if (code1 == TYPE_CODE_MEMBERPTR && code2 == TYPE_CODE_INT
           && value_as_long (arg2) == 0)
    {
      /* The Itanium C++ ABI represents NULL pointers to members as
         minus one, instead of biasing the normal case.  */
      return value_from_longest (type, -1);
    }
  else if (TYPE_LENGTH (type) == TYPE_LENGTH (type2))
    {
      if (code1 == TYPE_CODE_PTR && code2 == TYPE_CODE_PTR)
        return value_cast_pointers (type, arg2);

      arg2 = value_copy (arg2);
      deprecated_set_value_type (arg2, type);
      arg2 = value_change_enclosing_type (arg2, type);
      set_value_pointed_to_offset (arg2, 0);    /* pai: chk_val */
      return arg2;
    }
  else if (VALUE_LVAL (arg2) == lval_memory)
    return value_at_lazy (type, value_address (arg2));
  else if (code1 == TYPE_CODE_VOID)
    {
      return value_zero (type, not_lval);
    }
  else
    {
      error (_("Invalid cast."));
      return 0;
    }
}

/* Create a value of type TYPE that is zero, and return it.  */

struct value *
value_zero (struct type *type, enum lval_type lv)
{
  struct value *val = allocate_value (type);
  VALUE_LVAL (val) = lv;

  return val;
}

/* Create a value of numeric type TYPE that is one, and return it.  */

struct value *
value_one (struct type *type, enum lval_type lv)
{
  struct type *type1 = check_typedef (type);
  struct value *val;

  if (TYPE_CODE (type1) == TYPE_CODE_DECFLOAT)
    {
      gdb_byte v[16];
      decimal_from_string (v, TYPE_LENGTH (type), "1");
      val = value_from_decfloat (type, v);
    }
  else if (TYPE_CODE (type1) == TYPE_CODE_FLT)
    {
      val = value_from_double (type, (DOUBLEST) 1);
    }
  else if (is_integral_type (type1))
    {
      val = value_from_longest (type, (LONGEST) 1);
    }
  else
    {
      error (_("Not a numeric type."));
    }

  VALUE_LVAL (val) = lv;
  return val;
}

/* Return a value with type TYPE located at ADDR.

   Call value_at only if the data needs to be fetched immediately;
   if we can be 'lazy' and defer the fetch, perhaps indefinately, call
   value_at_lazy instead.  value_at_lazy simply records the address of
   the data and sets the lazy-evaluation-required flag.  The lazy flag
   is tested in the value_contents macro, which is used if and when
   the contents are actually required.

   Note: value_at does *NOT* handle embedded offsets; perform such
   adjustments before or after calling it.  */

struct value *
value_at (struct type *type, CORE_ADDR addr)
{
  struct value *val;

  if (TYPE_CODE (check_typedef (type)) == TYPE_CODE_VOID)
    error (_("Attempt to dereference a generic pointer."));

  val = allocate_value (type);

  read_memory (addr, value_contents_all_raw (val), TYPE_LENGTH (type));

  VALUE_LVAL (val) = lval_memory;
  set_value_address (val, addr);

  return val;
}

/* Return a lazy value with type TYPE located at ADDR (cf. value_at).  */

struct value *
value_at_lazy (struct type *type, CORE_ADDR addr)
{
  struct value *val;

  if (TYPE_CODE (check_typedef (type)) == TYPE_CODE_VOID)
    error (_("Attempt to dereference a generic pointer."));

  val = allocate_value_lazy (type);

  VALUE_LVAL (val) = lval_memory;
  set_value_address (val, addr);

  return val;
}

/* Called only from the value_contents and value_contents_all()
   macros, if the current data for a variable needs to be loaded into
   value_contents(VAL).  Fetches the data from the user's process, and
   clears the lazy flag to indicate that the data in the buffer is
   valid.

   If the value is zero-length, we avoid calling read_memory, which
   would abort.  We mark the value as fetched anyway -- all 0 bytes of
   it.

   This function returns a value because it is used in the
   value_contents macro as part of an expression, where a void would
   not work.  The value is ignored.  */

int
value_fetch_lazy (struct value *val)
{
  gdb_assert (value_lazy (val));
  allocate_value_contents (val);
  if (VALUE_LVAL (val) == lval_memory)
    {
      CORE_ADDR addr = value_address (val);
      int length = TYPE_LENGTH (check_typedef (value_enclosing_type (val)));

      if (length)
        read_memory (addr, value_contents_all_raw (val), length);
    }
  else if (VALUE_LVAL (val) == lval_register)
    {
      struct frame_info *frame;
      int regnum;
      struct type *type = check_typedef (value_type (val));
      struct value *new_val = val, *mark = value_mark ();

      /* Offsets are not supported here; lazy register values must
         refer to the entire register.  */
      gdb_assert (value_offset (val) == 0);

      while (VALUE_LVAL (new_val) == lval_register && value_lazy (new_val))
        {
          frame = frame_find_by_id (VALUE_FRAME_ID (new_val));
          regnum = VALUE_REGNUM (new_val);

          gdb_assert (frame != NULL);

          /* Convertible register routines are used for multi-register
             values and for interpretation in different types
             (e.g. float or int from a double register).  Lazy
             register values should have the register's natural type,
             so they do not apply.  */
          gdb_assert (!gdbarch_convert_register_p (get_frame_arch (frame),
                                                   regnum, type));

          new_val = get_frame_register_value (frame, regnum);
        }

      /* If it's still lazy (for instance, a saved register on the
         stack), fetch it.  */
      if (value_lazy (new_val))
        value_fetch_lazy (new_val);

      /* If the register was not saved, mark it unavailable.  */
      if (value_optimized_out (new_val))
        set_value_optimized_out (val, 1);
      else
        memcpy (value_contents_raw (val), value_contents (new_val),
                TYPE_LENGTH (type));

      if (frame_debug)
        {
          struct gdbarch *gdbarch;
          frame = frame_find_by_id (VALUE_FRAME_ID (val));
          regnum = VALUE_REGNUM (val);
          gdbarch = get_frame_arch (frame);

          fprintf_unfiltered (gdb_stdlog, "\
{ value_fetch_lazy (frame=%d,regnum=%d(%s),...) ",
                              frame_relative_level (frame), regnum,
                              user_reg_map_regnum_to_name (gdbarch, regnum));

          fprintf_unfiltered (gdb_stdlog, "->");
          if (value_optimized_out (new_val))
            fprintf_unfiltered (gdb_stdlog, " optimized out");
          else
            {
              int i;
              const gdb_byte *buf = value_contents (new_val);

              if (VALUE_LVAL (new_val) == lval_register)
                fprintf_unfiltered (gdb_stdlog, " register=%d",
                                    VALUE_REGNUM (new_val));
              else if (VALUE_LVAL (new_val) == lval_memory)
                fprintf_unfiltered (gdb_stdlog, " address=0x%s",
                                    paddr_nz (value_address (new_val)));
              else
                fprintf_unfiltered (gdb_stdlog, " computed");

              fprintf_unfiltered (gdb_stdlog, " bytes=");
              fprintf_unfiltered (gdb_stdlog, "[");
              for (i = 0; i < register_size (gdbarch, regnum); i++)
                fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]);
              fprintf_unfiltered (gdb_stdlog, "]");
            }

          fprintf_unfiltered (gdb_stdlog, " }\n");
        }

      /* Dispose of the intermediate values.  This prevents
         watchpoints from trying to watch the saved frame pointer.  */
      value_free_to_mark (mark);
    }
  else if (VALUE_LVAL (val) == lval_computed)
    value_computed_funcs (val)->read (val);
  else
    internal_error (__FILE__, __LINE__, "Unexpected lazy value type.");

  set_value_lazy (val, 0);
  return 0;
}


/* Store the contents of FROMVAL into the location of TOVAL.
   Return a new value with the location of TOVAL and contents of FROMVAL.  */

struct value *
value_assign (struct value *toval, struct value *fromval)
{
  struct type *type;
  struct value *val;
  struct frame_id old_frame;

  if (!deprecated_value_modifiable (toval))
    error (_("Left operand of assignment is not a modifiable lvalue."));

  toval = coerce_ref (toval);

  type = value_type (toval);
  if (VALUE_LVAL (toval) != lval_internalvar)
    {
      toval = value_coerce_to_target (toval);
      fromval = value_cast (type, fromval);
    }
  else
    {
      /* Coerce arrays and functions to pointers, except for arrays
         which only live in GDB's storage.  */
      if (!value_must_coerce_to_target (fromval))
        fromval = coerce_array (fromval);
    }

  CHECK_TYPEDEF (type);

  /* Since modifying a register can trash the frame chain, and
     modifying memory can trash the frame cache, we save the old frame
     and then restore the new frame afterwards.  */
  old_frame = get_frame_id (deprecated_safe_get_selected_frame ());

  switch (VALUE_LVAL (toval))
    {
    case lval_internalvar:
      set_internalvar (VALUE_INTERNALVAR (toval), fromval);
      val = value_copy (fromval);
      val = value_change_enclosing_type (val, 
                                         value_enclosing_type (fromval));
      set_value_embedded_offset (val, value_embedded_offset (fromval));
      set_value_pointed_to_offset (val, 
                                   value_pointed_to_offset (fromval));
      return val;

    case lval_internalvar_component:
      set_internalvar_component (VALUE_INTERNALVAR (toval),
                                 value_offset (toval),
                                 value_bitpos (toval),
                                 value_bitsize (toval),
                                 fromval);
      break;

    case lval_memory:
      {
        const gdb_byte *dest_buffer;
        CORE_ADDR changed_addr;
        int changed_len;
        gdb_byte buffer[sizeof (LONGEST)];

        if (value_bitsize (toval))
          {
            /* We assume that the argument to read_memory is in units
               of host chars.  FIXME: Is that correct?  */
            changed_len = (value_bitpos (toval)
                           + value_bitsize (toval)
                           + HOST_CHAR_BIT - 1)
              / HOST_CHAR_BIT;

            if (changed_len > (int) sizeof (LONGEST))
              error (_("Can't handle bitfields which don't fit in a %d bit word."),
                     (int) sizeof (LONGEST) * HOST_CHAR_BIT);

            read_memory (value_address (toval), buffer, changed_len);
            modify_field (type, buffer, value_as_long (fromval),
                          value_bitpos (toval), value_bitsize (toval));
            changed_addr = value_address (toval);
            dest_buffer = buffer;
          }
        else
          {
            changed_addr = value_address (toval);
            changed_len = TYPE_LENGTH (type);
            dest_buffer = value_contents (fromval);
          }

        write_memory (changed_addr, dest_buffer, changed_len);
        if (deprecated_memory_changed_hook)
          deprecated_memory_changed_hook (changed_addr, changed_len);
      }
      break;

    case lval_register:
      {
        struct frame_info *frame;
        struct gdbarch *gdbarch;
        int value_reg;

        /* Figure out which frame this is in currently.  */
        frame = frame_find_by_id (VALUE_FRAME_ID (toval));
        value_reg = VALUE_REGNUM (toval);

        if (!frame)
          error (_("Value being assigned to is no longer active."));

        gdbarch = get_frame_arch (frame);
        if (gdbarch_convert_register_p (gdbarch, VALUE_REGNUM (toval), type))
          {
            /* If TOVAL is a special machine register requiring
               conversion of program values to a special raw
               format.  */
            gdbarch_value_to_register (gdbarch, frame,
                                       VALUE_REGNUM (toval), type,
                                       value_contents (fromval));
          }
        else
          {
            if (value_bitsize (toval))
              {
                int changed_len;
                gdb_byte buffer[sizeof (LONGEST)];

                changed_len = (value_bitpos (toval)
                               + value_bitsize (toval)
                               + HOST_CHAR_BIT - 1)
                  / HOST_CHAR_BIT;

                if (changed_len > (int) sizeof (LONGEST))
                  error (_("Can't handle bitfields which don't fit in a %d bit word."),
                         (int) sizeof (LONGEST) * HOST_CHAR_BIT);

                get_frame_register_bytes (frame, value_reg,
                                          value_offset (toval),
                                          changed_len, buffer);

                modify_field (type, buffer, value_as_long (fromval),
                              value_bitpos (toval), value_bitsize (toval));

                put_frame_register_bytes (frame, value_reg,
                                          value_offset (toval),
                                          changed_len, buffer);
              }
            else
              {
                put_frame_register_bytes (frame, value_reg,
                                          value_offset (toval),
                                          TYPE_LENGTH (type),
                                          value_contents (fromval));
              }
          }

        if (deprecated_register_changed_hook)
          deprecated_register_changed_hook (-1);
        observer_notify_target_changed (&current_target);
        break;
      }

    case lval_computed:
      {
        struct lval_funcs *funcs = value_computed_funcs (toval);

        funcs->write (toval, fromval);
      }
      break;

    default:
      error (_("Left operand of assignment is not an lvalue."));
    }

  /* Assigning to the stack pointer, frame pointer, and other
     (architecture and calling convention specific) registers may
     cause the frame cache to be out of date.  Assigning to memory
     also can.  We just do this on all assignments to registers or
     memory, for simplicity's sake; I doubt the slowdown matters.  */
  switch (VALUE_LVAL (toval))
    {
    case lval_memory:
    case lval_register:

      reinit_frame_cache ();

      /* Having destroyed the frame cache, restore the selected
         frame.  */

      /* FIXME: cagney/2002-11-02: There has to be a better way of
         doing this.  Instead of constantly saving/restoring the
         frame.  Why not create a get_selected_frame() function that,
         having saved the selected frame's ID can automatically
         re-find the previously selected frame automatically.  */

      {
        struct frame_info *fi = frame_find_by_id (old_frame);
        if (fi != NULL)
          select_frame (fi);
      }

      break;
    default:
      break;
    }
  
  /* If the field does not entirely fill a LONGEST, then zero the sign
     bits.  If the field is signed, and is negative, then sign
     extend.  */
  if ((value_bitsize (toval) > 0)
      && (value_bitsize (toval) < 8 * (int) sizeof (LONGEST)))
    {
      LONGEST fieldval = value_as_long (fromval);
      LONGEST valmask = (((ULONGEST) 1) << value_bitsize (toval)) - 1;

      fieldval &= valmask;
      if (!TYPE_UNSIGNED (type) 
          && (fieldval & (valmask ^ (valmask >> 1))))
        fieldval |= ~valmask;

      fromval = value_from_longest (type, fieldval);
    }

  val = value_copy (toval);
  memcpy (value_contents_raw (val), value_contents (fromval),
          TYPE_LENGTH (type));
  deprecated_set_value_type (val, type);
  val = value_change_enclosing_type (val, 
                                     value_enclosing_type (fromval));
  set_value_embedded_offset (val, value_embedded_offset (fromval));
  set_value_pointed_to_offset (val, value_pointed_to_offset (fromval));

  return val;
}

/* Extend a value VAL to COUNT repetitions of its type.  */

struct value *
value_repeat (struct value *arg1, int count)
{
  struct value *val;

  if (VALUE_LVAL (arg1) != lval_memory)
    error (_("Only values in memory can be extended with '@'."));
  if (count < 1)
    error (_("Invalid number %d of repetitions."), count);

  val = allocate_repeat_value (value_enclosing_type (arg1), count);

  read_memory (value_address (arg1),
               value_contents_all_raw (val),
               TYPE_LENGTH (value_enclosing_type (val)));
  VALUE_LVAL (val) = lval_memory;
  set_value_address (val, value_address (arg1));

  return val;
}

struct value *
value_of_variable (struct symbol *var, struct block *b)
{
  struct value *val;
  struct frame_info *frame;

  if (!symbol_read_needs_frame (var))
    frame = NULL;
  else if (!b)
    frame = get_selected_frame (_("No frame selected."));
  else
    {
      frame = block_innermost_frame (b);
      if (!frame)
        {
          if (BLOCK_FUNCTION (b) && !block_inlined_p (b)
              && SYMBOL_PRINT_NAME (BLOCK_FUNCTION (b)))
            error (_("No frame is currently executing in block %s."),
                   SYMBOL_PRINT_NAME (BLOCK_FUNCTION (b)));
          else
            error (_("No frame is currently executing in specified block"));
        }
    }

  val = read_var_value (var, frame);
  if (!val)
    error (_("Address of symbol \"%s\" is unknown."), SYMBOL_PRINT_NAME (var));

  return val;
}

struct value *
address_of_variable (struct symbol *var, struct block *b)
{
  struct type *type = SYMBOL_TYPE (var);
  struct value *val;

  /* Evaluate it first; if the result is a memory address, we're fine.
     Lazy evaluation pays off here. */

  val = value_of_variable (var, b);

  if ((VALUE_LVAL (val) == lval_memory && value_lazy (val))
      || TYPE_CODE (type) == TYPE_CODE_FUNC)
    {
      CORE_ADDR addr = value_address (val);
      return value_from_pointer (lookup_pointer_type (type), addr);
    }

  /* Not a memory address; check what the problem was.  */
  switch (VALUE_LVAL (val))
    {
    case lval_register:
      {
        struct frame_info *frame;
        const char *regname;

        frame = frame_find_by_id (VALUE_FRAME_ID (val));
        gdb_assert (frame);

        regname = gdbarch_register_name (get_frame_arch (frame),
                                         VALUE_REGNUM (val));
        gdb_assert (regname && *regname);

        error (_("Address requested for identifier "
                 "\"%s\" which is in register $%s"),
               SYMBOL_PRINT_NAME (var), regname);
        break;
      }

    default:
      error (_("Can't take address of \"%s\" which isn't an lvalue."),
             SYMBOL_PRINT_NAME (var));
      break;
    }

  return val;
}

/* Return one if VAL does not live in target memory, but should in order
   to operate on it.  Otherwise return zero.  */

int
value_must_coerce_to_target (struct value *val)
{
  struct type *valtype;

  /* The only lval kinds which do not live in target memory.  */
  if (VALUE_LVAL (val) != not_lval
      && VALUE_LVAL (val) != lval_internalvar)
    return 0;

  valtype = check_typedef (value_type (val));

  switch (TYPE_CODE (valtype))
    {
    case TYPE_CODE_ARRAY:
    case TYPE_CODE_STRING:
      return 1;
    default:
      return 0;
    }
}

/* Make sure that VAL lives in target memory if it's supposed to.  For instance,
   strings are constructed as character arrays in GDB's storage, and this
   function copies them to the target.  */

struct value *
value_coerce_to_target (struct value *val)
{
  LONGEST length;
  CORE_ADDR addr;

  if (!value_must_coerce_to_target (val))
    return val;

  length = TYPE_LENGTH (check_typedef (value_type (val)));
  addr = allocate_space_in_inferior (length);
  write_memory (addr, value_contents (val), length);
  return value_at_lazy (value_type (val), addr);
}

/* Given a value which is an array, return a value which is a pointer
   to its first element, regardless of whether or not the array has a
   nonzero lower bound.

   FIXME: A previous comment here indicated that this routine should
   be substracting the array's lower bound.  It's not clear to me that
   this is correct.  Given an array subscripting operation, it would
   certainly work to do the adjustment here, essentially computing:

   (&array[0] - (lowerbound * sizeof array[0])) + (index * sizeof array[0])

   However I believe a more appropriate and logical place to account
   for the lower bound is to do so in value_subscript, essentially
   computing:

   (&array[0] + ((index - lowerbound) * sizeof array[0]))

   As further evidence consider what would happen with operations
   other than array subscripting, where the caller would get back a
   value that had an address somewhere before the actual first element
   of the array, and the information about the lower bound would be
   lost because of the coercion to pointer type.
 */

struct value *
value_coerce_array (struct value *arg1)
{
  struct type *type = check_typedef (value_type (arg1));

  /* If the user tries to do something requiring a pointer with an
     array that has not yet been pushed to the target, then this would
     be a good time to do so.  */
  arg1 = value_coerce_to_target (arg1);

  if (VALUE_LVAL (arg1) != lval_memory)
    error (_("Attempt to take address of value not located in memory."));

  return value_from_pointer (lookup_pointer_type (TYPE_TARGET_TYPE (type)),
                             value_address (arg1));
}

/* Given a value which is a function, return a value which is a pointer
   to it.  */

struct value *
value_coerce_function (struct value *arg1)
{
  struct value *retval;

  if (VALUE_LVAL (arg1) != lval_memory)
    error (_("Attempt to take address of value not located in memory."));

  retval = value_from_pointer (lookup_pointer_type (value_type (arg1)),
                               value_address (arg1));
  return retval;
}

/* Return a pointer value for the object for which ARG1 is the
   contents.  */

struct value *
value_addr (struct value *arg1)
{
  struct value *arg2;

  struct type *type = check_typedef (value_type (arg1));
  if (TYPE_CODE (type) == TYPE_CODE_REF)
    {
      /* Copy the value, but change the type from (T&) to (T*).  We
         keep the same location information, which is efficient, and
         allows &(&X) to get the location containing the reference.  */
      arg2 = value_copy (arg1);
      deprecated_set_value_type (arg2, 
                                 lookup_pointer_type (TYPE_TARGET_TYPE (type)));
      return arg2;
    }
  if (TYPE_CODE (type) == TYPE_CODE_FUNC)
    return value_coerce_function (arg1);

  /* If this is an array that has not yet been pushed to the target,
     then this would be a good time to force it to memory.  */
  arg1 = value_coerce_to_target (arg1);

  if (VALUE_LVAL (arg1) != lval_memory)
    error (_("Attempt to take address of value not located in memory."));

  /* Get target memory address */
  arg2 = value_from_pointer (lookup_pointer_type (value_type (arg1)),
                             (value_address (arg1)
                              + value_embedded_offset (arg1)));

  /* This may be a pointer to a base subobject; so remember the
     full derived object's type ...  */
  arg2 = value_change_enclosing_type (arg2, lookup_pointer_type (value_enclosing_type (arg1)));
  /* ... and also the relative position of the subobject in the full
     object.  */
  set_value_pointed_to_offset (arg2, value_embedded_offset (arg1));
  return arg2;
}

/* Return a reference value for the object for which ARG1 is the
   contents.  */

struct value *
value_ref (struct value *arg1)
{
  struct value *arg2;

  struct type *type = check_typedef (value_type (arg1));
  if (TYPE_CODE (type) == TYPE_CODE_REF)
    return arg1;

  arg2 = value_addr (arg1);
  deprecated_set_value_type (arg2, lookup_reference_type (type));
  return arg2;
}

/* Given a value of a pointer type, apply the C unary * operator to
   it.  */

struct value *
value_ind (struct value *arg1)
{
  struct type *base_type;
  struct value *arg2;

  arg1 = coerce_array (arg1);

  base_type = check_typedef (value_type (arg1));

  if (TYPE_CODE (base_type) == TYPE_CODE_PTR)
    {
      struct type *enc_type;
      /* We may be pointing to something embedded in a larger object.
         Get the real type of the enclosing object.  */
      enc_type = check_typedef (value_enclosing_type (arg1));
      enc_type = TYPE_TARGET_TYPE (enc_type);

      if (TYPE_CODE (check_typedef (enc_type)) == TYPE_CODE_FUNC
          || TYPE_CODE (check_typedef (enc_type)) == TYPE_CODE_METHOD)
        /* For functions, go through find_function_addr, which knows
           how to handle function descriptors.  */
        arg2 = value_at_lazy (enc_type, 
                              find_function_addr (arg1, NULL));
      else
        /* Retrieve the enclosing object pointed to */
        arg2 = value_at_lazy (enc_type, 
                              (value_as_address (arg1)
                               - value_pointed_to_offset (arg1)));

      /* Re-adjust type.  */
      deprecated_set_value_type (arg2, TYPE_TARGET_TYPE (base_type));
      /* Add embedding info.  */
      arg2 = value_change_enclosing_type (arg2, enc_type);
      set_value_embedded_offset (arg2, value_pointed_to_offset (arg1));

      /* We may be pointing to an object of some derived type.  */
      arg2 = value_full_object (arg2, NULL, 0, 0, 0);
      return arg2;
    }

  error (_("Attempt to take contents of a non-pointer value."));
  return 0;                     /* For lint -- never reached.  */
}
\f
/* Create a value for an array by allocating space in GDB, copying
   copying the data into that space, and then setting up an array
   value.

   The array bounds are set from LOWBOUND and HIGHBOUND, and the array
   is populated from the values passed in ELEMVEC.

   The element type of the array is inherited from the type of the
   first element, and all elements must have the same size (though we
   don't currently enforce any restriction on their types).  */

struct value *
value_array (int lowbound, int highbound, struct value **elemvec)
{
  int nelem;
  int idx;
  unsigned int typelength;
  struct value *val;
  struct type *arraytype;
  CORE_ADDR addr;

  /* Validate that the bounds are reasonable and that each of the
     elements have the same size.  */

  nelem = highbound - lowbound + 1;
  if (nelem <= 0)
    {
      error (_("bad array bounds (%d, %d)"), lowbound, highbound);
    }
  typelength = TYPE_LENGTH (value_enclosing_type (elemvec[0]));
  for (idx = 1; idx < nelem; idx++)
    {
      if (TYPE_LENGTH (value_enclosing_type (elemvec[idx])) != typelength)
        {
          error (_("array elements must all be the same size"));
        }
    }

  arraytype = lookup_array_range_type (value_enclosing_type (elemvec[0]),
                                       lowbound, highbound);

  if (!current_language->c_style_arrays)
    {
      val = allocate_value (arraytype);
      for (idx = 0; idx < nelem; idx++)
        {
          memcpy (value_contents_all_raw (val) + (idx * typelength),
                  value_contents_all (elemvec[idx]),
                  typelength);
        }
      return val;
    }

  /* Allocate space to store the array, and then initialize it by
     copying in each element.  */

  val = allocate_value (arraytype);
  for (idx = 0; idx < nelem; idx++)
    memcpy (value_contents_writeable (val) + (idx * typelength),
            value_contents_all (elemvec[idx]),
            typelength);
  return val;
}

struct value *
value_cstring (char *ptr, int len, struct type *char_type)
{
  struct value *val;
  int lowbound = current_language->string_lower_bound;
  int highbound = len / TYPE_LENGTH (char_type);
  struct type *stringtype
    = lookup_array_range_type (char_type, lowbound, highbound + lowbound - 1);

  val = allocate_value (stringtype);
  memcpy (value_contents_raw (val), ptr, len);
  return val;
}

/* Create a value for a string constant by allocating space in the
   inferior, copying the data into that space, and returning the
   address with type TYPE_CODE_STRING.  PTR points to the string
   constant data; LEN is number of characters.

   Note that string types are like array of char types with a lower
   bound of zero and an upper bound of LEN - 1.  Also note that the
   string may contain embedded null bytes.  */

struct value *
value_string (char *ptr, int len, struct type *char_type)
{
  struct value *val;
  int lowbound = current_language->string_lower_bound;
  int highbound = len / TYPE_LENGTH (char_type);
  struct type *stringtype
    = lookup_string_range_type (char_type, lowbound, highbound + lowbound - 1);

  val = allocate_value (stringtype);
  memcpy (value_contents_raw (val), ptr, len);
  return val;
}

struct value *
value_bitstring (char *ptr, int len, struct type *index_type)
{
  struct value *val;
  struct type *domain_type
    = create_range_type (NULL, index_type, 0, len - 1);
  struct type *type = create_set_type (NULL, domain_type);
  TYPE_CODE (type) = TYPE_CODE_BITSTRING;
  val = allocate_value (type);
  memcpy (value_contents_raw (val), ptr, TYPE_LENGTH (type));
  return val;
}
\f
/* See if we can pass arguments in T2 to a function which takes
   arguments of types T1.  T1 is a list of NARGS arguments, and T2 is
   a NULL-terminated vector.  If some arguments need coercion of some
   sort, then the coerced values are written into T2.  Return value is
   0 if the arguments could be matched, or the position at which they
   differ if not.

   STATICP is nonzero if the T1 argument list came from a static
   member function.  T2 will still include the ``this'' pointer, but
   it will be skipped.

   For non-static member functions, we ignore the first argument,
   which is the type of the instance variable.  This is because we
   want to handle calls with objects from derived classes.  This is
   not entirely correct: we should actually check to make sure that a
   requested operation is type secure, shouldn't we?  FIXME.  */

static int
typecmp (int staticp, int varargs, int nargs,
         struct field t1[], struct value *t2[])
{
  int i;

  if (t2 == 0)
    internal_error (__FILE__, __LINE__, 
                    _("typecmp: no argument list"));

  /* Skip ``this'' argument if applicable.  T2 will always include
     THIS.  */
  if (staticp)
    t2 ++;

  for (i = 0;
       (i < nargs) && TYPE_CODE (t1[i].type) != TYPE_CODE_VOID;
       i++)
    {
      struct type *tt1, *tt2;

      if (!t2[i])
        return i + 1;

      tt1 = check_typedef (t1[i].type);
      tt2 = check_typedef (value_type (t2[i]));

      if (TYPE_CODE (tt1) == TYPE_CODE_REF
      /* We should be doing hairy argument matching, as below.  */
          && (TYPE_CODE (check_typedef (TYPE_TARGET_TYPE (tt1))) == TYPE_CODE (tt2)))
        {
          if (TYPE_CODE (tt2) == TYPE_CODE_ARRAY)
            t2[i] = value_coerce_array (t2[i]);
          else
            t2[i] = value_ref (t2[i]);
          continue;
        }

      /* djb - 20000715 - Until the new type structure is in the
         place, and we can attempt things like implicit conversions,
         we need to do this so you can take something like a map<const
         char *>, and properly access map["hello"], because the
         argument to [] will be a reference to a pointer to a char,
         and the argument will be a pointer to a char.  */
      while (TYPE_CODE(tt1) == TYPE_CODE_REF
             || TYPE_CODE (tt1) == TYPE_CODE_PTR)
        {
          tt1 = check_typedef( TYPE_TARGET_TYPE(tt1) );
        }
      while (TYPE_CODE(tt2) == TYPE_CODE_ARRAY
             || TYPE_CODE(tt2) == TYPE_CODE_PTR
             || TYPE_CODE(tt2) == TYPE_CODE_REF)
        {
          tt2 = check_typedef (TYPE_TARGET_TYPE(tt2));
        }
      if (TYPE_CODE (tt1) == TYPE_CODE (tt2))
        continue;
      /* Array to pointer is a `trivial conversion' according to the
         ARM.  */

      /* We should be doing much hairier argument matching (see
         section 13.2 of the ARM), but as a quick kludge, just check
         for the same type code.  */
      if (TYPE_CODE (t1[i].type) != TYPE_CODE (value_type (t2[i])))
        return i + 1;
    }
  if (varargs || t2[i] == NULL)
    return 0;
  return i + 1;
}

/* Helper function used by value_struct_elt to recurse through
   baseclasses.  Look for a field NAME in ARG1. Adjust the address of
   ARG1 by OFFSET bytes, and search in it assuming it has (class) type
   TYPE.  If found, return value, else return NULL.

   If LOOKING_FOR_BASECLASS, then instead of looking for struct
   fields, look for a baseclass named NAME.  */

static struct value *
search_struct_field (char *name, struct value *arg1, int offset,
                     struct type *type, int looking_for_baseclass)
{
  int i;
  int nbases = TYPE_N_BASECLASSES (type);

  CHECK_TYPEDEF (type);

  if (!looking_for_baseclass)
    for (i = TYPE_NFIELDS (type) - 1; i >= nbases; i--)
      {
        char *t_field_name = TYPE_FIELD_NAME (type, i);

        if (t_field_name && (strcmp_iw (t_field_name, name) == 0))
          {
            struct value *v;
            if (field_is_static (&TYPE_FIELD (type, i)))
              {
                v = value_static_field (type, i);
                if (v == 0)
                  error (_("field %s is nonexistent or has been optimised out"),
                         name);
              }
            else
              {
                v = value_primitive_field (arg1, offset, i, type);
                if (v == 0)
                  error (_("there is no field named %s"), name);
              }
            return v;
          }

        if (t_field_name
            && (t_field_name[0] == '\0'
                || (TYPE_CODE (type) == TYPE_CODE_UNION
                    && (strcmp_iw (t_field_name, "else") == 0))))
          {
            struct type *field_type = TYPE_FIELD_TYPE (type, i);
            if (TYPE_CODE (field_type) == TYPE_CODE_UNION
                || TYPE_CODE (field_type) == TYPE_CODE_STRUCT)
              {
                /* Look for a match through the fields of an anonymous
                   union, or anonymous struct.  C++ provides anonymous
                   unions.

                   In the GNU Chill (now deleted from GDB)
                   implementation of variant record types, each
                   <alternative field> has an (anonymous) union type,
                   each member of the union represents a <variant
                   alternative>.  Each <variant alternative> is
                   represented as a struct, with a member for each
                   <variant field>.  */

                struct value *v;
                int new_offset = offset;

                /* This is pretty gross.  In G++, the offset in an
                   anonymous union is relative to the beginning of the
                   enclosing struct.  In the GNU Chill (now deleted
                   from GDB) implementation of variant records, the
                   bitpos is zero in an anonymous union field, so we
                   have to add the offset of the union here.  */
                if (TYPE_CODE (field_type) == TYPE_CODE_STRUCT
                    || (TYPE_NFIELDS (field_type) > 0
                        && TYPE_FIELD_BITPOS (field_type, 0) == 0))
                  new_offset += TYPE_FIELD_BITPOS (type, i) / 8;

                v = search_struct_field (name, arg1, new_offset, 
                                         field_type,
                                         looking_for_baseclass);
                if (v)
                  return v;
              }
          }
      }

  for (i = 0; i < nbases; i++)
    {
      struct value *v;
      struct type *basetype = check_typedef (TYPE_BASECLASS (type, i));
      /* If we are looking for baseclasses, this is what we get when
         we hit them.  But it could happen that the base part's member
         name is not yet filled in.  */
      int found_baseclass = (looking_for_baseclass
                             && TYPE_BASECLASS_NAME (type, i) != NULL
                             && (strcmp_iw (name, 
                                            TYPE_BASECLASS_NAME (type, 
                                                                 i)) == 0));

      if (BASETYPE_VIA_VIRTUAL (type, i))
        {
          int boffset;
          struct value *v2;

          boffset = baseclass_offset (type, i,
                                      value_contents (arg1) + offset,
                                      value_address (arg1) + offset);
          if (boffset == -1)
            error (_("virtual baseclass botch"));

          /* The virtual base class pointer might have been clobbered
             by the user program. Make sure that it still points to a
             valid memory location.  */

          boffset += offset;
          if (boffset < 0 || boffset >= TYPE_LENGTH (type))
            {
              CORE_ADDR base_addr;

              v2  = allocate_value (basetype);
              base_addr = value_address (arg1) + boffset;
              if (target_read_memory (base_addr, 
                                      value_contents_raw (v2),
                                      TYPE_LENGTH (basetype)) != 0)
                error (_("virtual baseclass botch"));
              VALUE_LVAL (v2) = lval_memory;
              set_value_address (v2, base_addr);
            }
          else
            {
              if (VALUE_LVAL (arg1) == lval_memory && value_lazy (arg1))
                v2  = allocate_value_lazy (basetype);
              else
                {
                  v2  = allocate_value (basetype);
                  memcpy (value_contents_raw (v2),
                          value_contents_raw (arg1) + boffset,
                          TYPE_LENGTH (basetype));
                }
              set_value_component_location (v2, arg1);
              VALUE_FRAME_ID (v2) = VALUE_FRAME_ID (arg1);
              set_value_offset (v2, value_offset (arg1) + boffset);
            }

          if (found_baseclass)
            return v2;
          v = search_struct_field (name, v2, 0,
                                   TYPE_BASECLASS (type, i),
                                   looking_for_baseclass);
        }
      else if (found_baseclass)
        v = value_primitive_field (arg1, offset, i, type);
      else
        v = search_struct_field (name, arg1,
                                 offset + TYPE_BASECLASS_BITPOS (type, 
                                                                 i) / 8,
                                 basetype, looking_for_baseclass);
      if (v)
        return v;
    }
  return NULL;
}

/* Helper function used by value_struct_elt to recurse through
   baseclasses.  Look for a field NAME in ARG1. Adjust the address of
   ARG1 by OFFSET bytes, and search in it assuming it has (class) type
   TYPE.

   If found, return value, else if name matched and args not return
   (value) -1, else return NULL.  */

static struct value *
search_struct_method (char *name, struct value **arg1p,
                      struct value **args, int offset,
                      int *static_memfuncp, struct type *type)
{
  int i;
  struct value *v;
  int name_matched = 0;
  char dem_opname[64];

  CHECK_TYPEDEF (type);
  for (i = TYPE_NFN_FIELDS (type) - 1; i >= 0; i--)
    {
      char *t_field_name = TYPE_FN_FIELDLIST_NAME (type, i);
      /* FIXME!  May need to check for ARM demangling here */
      if (strncmp (t_field_name, "__", 2) == 0 ||
          strncmp (t_field_name, "op", 2) == 0 ||
          strncmp (t_field_name, "type", 4) == 0)
        {
          if (cplus_demangle_opname (t_field_name, dem_opname, DMGL_ANSI))
            t_field_name = dem_opname;
          else if (cplus_demangle_opname (t_field_name, dem_opname, 0))
            t_field_name = dem_opname;
        }
      if (t_field_name && (strcmp_iw (t_field_name, name) == 0))
        {
          int j = TYPE_FN_FIELDLIST_LENGTH (type, i) - 1;
          struct fn_field *f = TYPE_FN_FIELDLIST1 (type, i);
          name_matched = 1;

          check_stub_method_group (type, i);
          if (j > 0 && args == 0)
            error (_("cannot resolve overloaded method `%s': no arguments supplied"), name);
          else if (j == 0 && args == 0)
            {
              v = value_fn_field (arg1p, f, j, type, offset);
              if (v != NULL)
                return v;
            }
          else
            while (j >= 0)
              {
                if (!typecmp (TYPE_FN_FIELD_STATIC_P (f, j),
                              TYPE_VARARGS (TYPE_FN_FIELD_TYPE (f, j)),
                              TYPE_NFIELDS (TYPE_FN_FIELD_TYPE (f, j)),
                              TYPE_FN_FIELD_ARGS (f, j), args))
                  {
                    if (TYPE_FN_FIELD_VIRTUAL_P (f, j))
                      return value_virtual_fn_field (arg1p, f, j, 
                                                     type, offset);
                    if (TYPE_FN_FIELD_STATIC_P (f, j) 
                        && static_memfuncp)
                      *static_memfuncp = 1;
                    v = value_fn_field (arg1p, f, j, type, offset);
                    if (v != NULL)
                      return v;       
                  }
                j--;
              }
        }
    }

  for (i = TYPE_N_BASECLASSES (type) - 1; i >= 0; i--)
    {
      int base_offset;

      if (BASETYPE_VIA_VIRTUAL (type, i))
        {
          struct type *baseclass = check_typedef (TYPE_BASECLASS (type, i));
          const gdb_byte *base_valaddr;

          /* The virtual base class pointer might have been
             clobbered by the user program. Make sure that it
            still points to a valid memory location.  */

          if (offset < 0 || offset >= TYPE_LENGTH (type))
            {
              gdb_byte *tmp = alloca (TYPE_LENGTH (baseclass));
              if (target_read_memory (value_address (*arg1p) + offset,
                                      tmp, TYPE_LENGTH (baseclass)) != 0)
                error (_("virtual baseclass botch"));
              base_valaddr = tmp;
            }
          else
            base_valaddr = value_contents (*arg1p) + offset;

          base_offset = baseclass_offset (type, i, base_valaddr,
                                          value_address (*arg1p) + offset);
          if (base_offset == -1)
            error (_("virtual baseclass botch"));
        }
      else
        {
          base_offset = TYPE_BASECLASS_BITPOS (type, i) / 8;
        }
      v = search_struct_method (name, arg1p, args, base_offset + offset,
                                static_memfuncp, TYPE_BASECLASS (type, i));
      if (v == (struct value *) - 1)
        {
          name_matched = 1;
        }
      else if (v)
        {
          /* FIXME-bothner:  Why is this commented out?  Why is it here?  */
          /* *arg1p = arg1_tmp; */
          return v;
        }
    }
  if (name_matched)
    return (struct value *) - 1;
  else
    return NULL;
}

/* Given *ARGP, a value of type (pointer to a)* structure/union,
   extract the component named NAME from the ultimate target
   structure/union and return it as a value with its appropriate type.
   ERR is used in the error message if *ARGP's type is wrong.

   C++: ARGS is a list of argument types to aid in the selection of
   an appropriate method. Also, handle derived types.

   STATIC_MEMFUNCP, if non-NULL, points to a caller-supplied location
   where the truthvalue of whether the function that was resolved was
   a static member function or not is stored.

   ERR is an error message to be printed in case the field is not
   found.  */

struct value *
value_struct_elt (struct value **argp, struct value **args,
                  char *name, int *static_memfuncp, char *err)
{
  struct type *t;
  struct value *v;

  *argp = coerce_array (*argp);

  t = check_typedef (value_type (*argp));

  /* Follow pointers until we get to a non-pointer.  */

  while (TYPE_CODE (t) == TYPE_CODE_PTR || TYPE_CODE (t) == TYPE_CODE_REF)
    {
      *argp = value_ind (*argp);
      /* Don't coerce fn pointer to fn and then back again!  */
      if (TYPE_CODE (value_type (*argp)) != TYPE_CODE_FUNC)
        *argp = coerce_array (*argp);
      t = check_typedef (value_type (*argp));
    }

  if (TYPE_CODE (t) != TYPE_CODE_STRUCT
      && TYPE_CODE (t) != TYPE_CODE_UNION)
    error (_("Attempt to extract a component of a value that is not a %s."), err);

  /* Assume it's not, unless we see that it is.  */
  if (static_memfuncp)
    *static_memfuncp = 0;

  if (!args)
    {
      /* if there are no arguments ...do this...  */

      /* Try as a field first, because if we succeed, there is less
         work to be done.  */
      v = search_struct_field (name, *argp, 0, t, 0);
      if (v)
        return v;

      /* C++: If it was not found as a data field, then try to
         return it as a pointer to a method.  */
      v = search_struct_method (name, argp, args, 0, 
                                static_memfuncp, t);

      if (v == (struct value *) - 1)
        error (_("Cannot take address of method %s."), name);
      else if (v == 0)
        {
          if (TYPE_NFN_FIELDS (t))
            error (_("There is no member or method named %s."), name);
          else
            error (_("There is no member named %s."), name);
        }
      return v;
    }

    v = search_struct_method (name, argp, args, 0, 
                              static_memfuncp, t);
  
  if (v == (struct value *) - 1)
    {
      error (_("One of the arguments you tried to pass to %s could not be converted to what the function wants."), name);
    }
  else if (v == 0)
    {
      /* See if user tried to invoke data as function.  If so, hand it
         back.  If it's not callable (i.e., a pointer to function),
         gdb should give an error.  */
      v = search_struct_field (name, *argp, 0, t, 0);
      /* If we found an ordinary field, then it is not a method call.
         So, treat it as if it were a static member function.  */
      if (v && static_memfuncp)
        *static_memfuncp = 1;
    }

  if (!v)
    error (_("Structure has no component named %s."), name);
  return v;
}

/* Search through the methods of an object (and its bases) to find a
   specified method.  Return the pointer to the fn_field list of
   overloaded instances.

   Helper function for value_find_oload_list.
   ARGP is a pointer to a pointer to a value (the object).
   METHOD is a string containing the method name.
   OFFSET is the offset within the value.
   TYPE is the assumed type of the object.
   NUM_FNS is the number of overloaded instances.
   BASETYPE is set to the actual type of the subobject where the
      method is found.
   BOFFSET is the offset of the base subobject where the method is found.
*/

static struct fn_field *
find_method_list (struct value **argp, char *method,
                  int offset, struct type *type, int *num_fns,
                  struct type **basetype, int *boffset)
{
  int i;
  struct fn_field *f;
  CHECK_TYPEDEF (type);

  *num_fns = 0;

  /* First check in object itself.  */
  for (i = TYPE_NFN_FIELDS (type) - 1; i >= 0; i--)
    {
      /* pai: FIXME What about operators and type conversions?  */
      char *fn_field_name = TYPE_FN_FIELDLIST_NAME (type, i);
      if (fn_field_name && (strcmp_iw (fn_field_name, method) == 0))
        {
          int len = TYPE_FN_FIELDLIST_LENGTH (type, i);
          struct fn_field *f = TYPE_FN_FIELDLIST1 (type, i);

          *num_fns = len;
          *basetype = type;
          *boffset = offset;

          /* Resolve any stub methods.  */
          check_stub_method_group (type, i);

          return f;
        }
    }

  /* Not found in object, check in base subobjects.  */
  for (i = TYPE_N_BASECLASSES (type) - 1; i >= 0; i--)
    {
      int base_offset;
      if (BASETYPE_VIA_VIRTUAL (type, i))
        {
          base_offset = value_offset (*argp) + offset;
          base_offset = baseclass_offset (type, i,
                                          value_contents (*argp) + base_offset,
                                          value_address (*argp) + base_offset);
          if (base_offset == -1)
            error (_("virtual baseclass botch"));
        }
      else /* Non-virtual base, simply use bit position from debug
              info.  */
        {
          base_offset = TYPE_BASECLASS_BITPOS (type, i) / 8;
        }
      f = find_method_list (argp, method, base_offset + offset,
                            TYPE_BASECLASS (type, i), num_fns, 
                            basetype, boffset);
      if (f)
        return f;
    }
  return NULL;
}

/* Return the list of overloaded methods of a specified name.

   ARGP is a pointer to a pointer to a value (the object).
   METHOD is the method name.
   OFFSET is the offset within the value contents.
   NUM_FNS is the number of overloaded instances.
   BASETYPE is set to the type of the base subobject that defines the
      method.
   BOFFSET is the offset of the base subobject which defines the method. 
*/

struct fn_field *
value_find_oload_method_list (struct value **argp, char *method, 
                              int offset, int *num_fns, 
                              struct type **basetype, int *boffset)
{
  struct type *t;

  t = check_typedef (value_type (*argp));

  /* Code snarfed from value_struct_elt.  */
  while (TYPE_CODE (t) == TYPE_CODE_PTR || TYPE_CODE (t) == TYPE_CODE_REF)
    {
      *argp = value_ind (*argp);
      /* Don't coerce fn pointer to fn and then back again!  */
      if (TYPE_CODE (value_type (*argp)) != TYPE_CODE_FUNC)
        *argp = coerce_array (*argp);
      t = check_typedef (value_type (*argp));
    }

  if (TYPE_CODE (t) != TYPE_CODE_STRUCT
      && TYPE_CODE (t) != TYPE_CODE_UNION)
    error (_("Attempt to extract a component of a value that is not a struct or union"));

  return find_method_list (argp, method, 0, t, num_fns, 
                           basetype, boffset);
}

/* Given an array of argument types (ARGTYPES) (which includes an
   entry for "this" in the case of C++ methods), the number of
   arguments NARGS, the NAME of a function whether it's a method or
   not (METHOD), and the degree of laxness (LAX) in conforming to
   overload resolution rules in ANSI C++, find the best function that
   matches on the argument types according to the overload resolution
   rules.

   In the case of class methods, the parameter OBJ is an object value
   in which to search for overloaded methods.

   In the case of non-method functions, the parameter FSYM is a symbol
   corresponding to one of the overloaded functions.

   Return value is an integer: 0 -> good match, 10 -> debugger applied
   non-standard coercions, 100 -> incompatible.

   If a method is being searched for, VALP will hold the value.
   If a non-method is being searched for, SYMP will hold the symbol 
   for it.

   If a method is being searched for, and it is a static method,
   then STATICP will point to a non-zero value.

   Note: This function does *not* check the value of
   overload_resolution.  Caller must check it to see whether overload
   resolution is permitted.
*/

int
find_overload_match (struct type **arg_types, int nargs, 
                     char *name, int method, int lax, 
                     struct value **objp, struct symbol *fsym,
                     struct value **valp, struct symbol **symp, 
                     int *staticp)
{
  struct value *obj = (objp ? *objp : NULL);
  /* Index of best overloaded function.  */
  int oload_champ;
  /* The measure for the current best match.  */
  struct badness_vector *oload_champ_bv = NULL;
  struct value *temp = obj;
  /* For methods, the list of overloaded methods.  */
  struct fn_field *fns_ptr = NULL;
  /* For non-methods, the list of overloaded function symbols.  */
  struct symbol **oload_syms = NULL;
  /* Number of overloaded instances being considered.  */
  int num_fns = 0;
  struct type *basetype = NULL;
  int boffset;
  int ix;
  int static_offset;
  struct cleanup *old_cleanups = NULL;

  const char *obj_type_name = NULL;
  char *func_name = NULL;
  enum oload_classification match_quality;

  /* Get the list of overloaded methods or functions.  */
  if (method)
    {
      gdb_assert (obj);
      obj_type_name = TYPE_NAME (value_type (obj));
      /* Hack: evaluate_subexp_standard often passes in a pointer
         value rather than the object itself, so try again.  */
      if ((!obj_type_name || !*obj_type_name) 
          && (TYPE_CODE (value_type (obj)) == TYPE_CODE_PTR))
        obj_type_name = TYPE_NAME (TYPE_TARGET_TYPE (value_type (obj)));

      fns_ptr = value_find_oload_method_list (&temp, name, 
                                              0, &num_fns, 
                                              &basetype, &boffset);
      if (!fns_ptr || !num_fns)
        error (_("Couldn't find method %s%s%s"),
               obj_type_name,
               (obj_type_name && *obj_type_name) ? "::" : "",
               name);
      /* If we are dealing with stub method types, they should have
         been resolved by find_method_list via
         value_find_oload_method_list above.  */
      gdb_assert (TYPE_DOMAIN_TYPE (fns_ptr[0].type) != NULL);
      oload_champ = find_oload_champ (arg_types, nargs, method, 
                                      num_fns, fns_ptr, 
                                      oload_syms, &oload_champ_bv);
    }
  else
    {
      const char *qualified_name = SYMBOL_CPLUS_DEMANGLED_NAME (fsym);

      /* If we have a C++ name, try to extract just the function
         part.  */
      if (qualified_name)
        func_name = cp_func_name (qualified_name);

      /* If there was no C++ name, this must be a C-style function.
         Just return the same symbol.  Do the same if cp_func_name
         fails for some reason.  */
      if (func_name == NULL)
        {
          *symp = fsym;
          return 0;
        }

      old_cleanups = make_cleanup (xfree, func_name);
      make_cleanup (xfree, oload_syms);
      make_cleanup (xfree, oload_champ_bv);

      oload_champ = find_oload_champ_namespace (arg_types, nargs,
                                                func_name,
                                                qualified_name,
                                                &oload_syms,
                                                &oload_champ_bv);
    }

  /* Check how bad the best match is.  */

  match_quality =
    classify_oload_match (oload_champ_bv, nargs,
                          oload_method_static (method, fns_ptr,
                                               oload_champ));

  if (match_quality == INCOMPATIBLE)
    {
      if (method)
        error (_("Cannot resolve method %s%s%s to any overloaded instance"),
               obj_type_name,
               (obj_type_name && *obj_type_name) ? "::" : "",
               name);
      else
        error (_("Cannot resolve function %s to any overloaded instance"),
               func_name);
    }
  else if (match_quality == NON_STANDARD)
    {
      if (method)
        warning (_("Using non-standard conversion to match method %s%s%s to supplied arguments"),
                 obj_type_name,
                 (obj_type_name && *obj_type_name) ? "::" : "",
                 name);
      else
        warning (_("Using non-standard conversion to match function %s to supplied arguments"),
                 func_name);
    }

  if (method)
    {
      if (staticp != NULL)
        *staticp = oload_method_static (method, fns_ptr, oload_champ);
      if (TYPE_FN_FIELD_VIRTUAL_P (fns_ptr, oload_champ))
        *valp = value_virtual_fn_field (&temp, fns_ptr, oload_champ, 
                                        basetype, boffset);
      else
        *valp = value_fn_field (&temp, fns_ptr, oload_champ, 
                                basetype, boffset);
    }
  else
    {
      *symp = oload_syms[oload_champ];
    }

  if (objp)
    {
      struct type *temp_type = check_typedef (value_type (temp));
      struct type *obj_type = check_typedef (value_type (*objp));
      if (TYPE_CODE (temp_type) != TYPE_CODE_PTR
          && (TYPE_CODE (obj_type) == TYPE_CODE_PTR
              || TYPE_CODE (obj_type) == TYPE_CODE_REF))
        {
          temp = value_addr (temp);
        }
      *objp = temp;
    }
  if (old_cleanups != NULL)
    do_cleanups (old_cleanups);

  switch (match_quality)
    {
    case INCOMPATIBLE:
      return 100;
    case NON_STANDARD:
      return 10;
    default:                            /* STANDARD */
      return 0;
    }
}

/* Find the best overload match, searching for FUNC_NAME in namespaces
   contained in QUALIFIED_NAME until it either finds a good match or
   runs out of namespaces.  It stores the overloaded functions in
   *OLOAD_SYMS, and the badness vector in *OLOAD_CHAMP_BV.  The
   calling function is responsible for freeing *OLOAD_SYMS and
   *OLOAD_CHAMP_BV.  */

static int
find_oload_champ_namespace (struct type **arg_types, int nargs,
                            const char *func_name,
                            const char *qualified_name,
                            struct symbol ***oload_syms,
                            struct badness_vector **oload_champ_bv)
{
  int oload_champ;

  find_oload_champ_namespace_loop (arg_types, nargs,
                                   func_name,
                                   qualified_name, 0,
                                   oload_syms, oload_champ_bv,
                                   &oload_champ);

  return oload_champ;
}

/* Helper function for find_oload_champ_namespace; NAMESPACE_LEN is
   how deep we've looked for namespaces, and the champ is stored in
   OLOAD_CHAMP.  The return value is 1 if the champ is a good one, 0
   if it isn't.

   It is the caller's responsibility to free *OLOAD_SYMS and
   *OLOAD_CHAMP_BV.  */

static int
find_oload_champ_namespace_loop (struct type **arg_types, int nargs,
                                 const char *func_name,
                                 const char *qualified_name,
                                 int namespace_len,
                                 struct symbol ***oload_syms,
                                 struct badness_vector **oload_champ_bv,
                                 int *oload_champ)
{
  int next_namespace_len = namespace_len;
  int searched_deeper = 0;
  int num_fns = 0;
  struct cleanup *old_cleanups;
  int new_oload_champ;
  struct symbol **new_oload_syms;
  struct badness_vector *new_oload_champ_bv;
  char *new_namespace;

  if (next_namespace_len != 0)
    {
      gdb_assert (qualified_name[next_namespace_len] == ':');
      next_namespace_len +=  2;
    }
  next_namespace_len +=
    cp_find_first_component (qualified_name + next_namespace_len);

  /* Initialize these to values that can safely be xfree'd.  */
  *oload_syms = NULL;
  *oload_champ_bv = NULL;

  /* First, see if we have a deeper namespace we can search in.  
     If we get a good match there, use it.  */

  if (qualified_name[next_namespace_len] == ':')
    {
      searched_deeper = 1;

      if (find_oload_champ_namespace_loop (arg_types, nargs,
                                           func_name, qualified_name,
                                           next_namespace_len,
                                           oload_syms, oload_champ_bv,
                                           oload_champ))
        {
          return 1;
        }
    };

  /* If we reach here, either we're in the deepest namespace or we
     didn't find a good match in a deeper namespace.  But, in the
     latter case, we still have a bad match in a deeper namespace;
     note that we might not find any match at all in the current
     namespace.  (There's always a match in the deepest namespace,
     because this overload mechanism only gets called if there's a
     function symbol to start off with.)  */

  old_cleanups = make_cleanup (xfree, *oload_syms);
  old_cleanups = make_cleanup (xfree, *oload_champ_bv);
  new_namespace = alloca (namespace_len + 1);
  strncpy (new_namespace, qualified_name, namespace_len);
  new_namespace[namespace_len] = '\0';
  new_oload_syms = make_symbol_overload_list (func_name,
                                              new_namespace);
  while (new_oload_syms[num_fns])
    ++num_fns;

  new_oload_champ = find_oload_champ (arg_types, nargs, 0, num_fns,
                                      NULL, new_oload_syms,
                                      &new_oload_champ_bv);

  /* Case 1: We found a good match.  Free earlier matches (if any),
     and return it.  Case 2: We didn't find a good match, but we're
     not the deepest function.  Then go with the bad match that the
     deeper function found.  Case 3: We found a bad match, and we're
     the deepest function.  Then return what we found, even though
     it's a bad match.  */

  if (new_oload_champ != -1
      && classify_oload_match (new_oload_champ_bv, nargs, 0) == STANDARD)
    {
      *oload_syms = new_oload_syms;
      *oload_champ = new_oload_champ;
      *oload_champ_bv = new_oload_champ_bv;
      do_cleanups (old_cleanups);
      return 1;
    }
  else if (searched_deeper)
    {
      xfree (new_oload_syms);
      xfree (new_oload_champ_bv);
      discard_cleanups (old_cleanups);
      return 0;
    }
  else
    {
      gdb_assert (new_oload_champ != -1);
      *oload_syms = new_oload_syms;
      *oload_champ = new_oload_champ;
      *oload_champ_bv = new_oload_champ_bv;
      discard_cleanups (old_cleanups);
      return 0;
    }
}

/* Look for a function to take NARGS args of types ARG_TYPES.  Find
   the best match from among the overloaded methods or functions
   (depending on METHOD) given by FNS_PTR or OLOAD_SYMS, respectively.
   The number of methods/functions in the list is given by NUM_FNS.
   Return the index of the best match; store an indication of the
   quality of the match in OLOAD_CHAMP_BV.

   It is the caller's responsibility to free *OLOAD_CHAMP_BV.  */

static int
find_oload_champ (struct type **arg_types, int nargs, int method,
                  int num_fns, struct fn_field *fns_ptr,
                  struct symbol **oload_syms,
                  struct badness_vector **oload_champ_bv)
{
  int ix;
  /* A measure of how good an overloaded instance is.  */
  struct badness_vector *bv;
  /* Index of best overloaded function.  */
  int oload_champ = -1;
  /* Current ambiguity state for overload resolution.  */
  int oload_ambiguous = 0;
  /* 0 => no ambiguity, 1 => two good funcs, 2 => incomparable funcs.  */

  *oload_champ_bv = NULL;

  /* Consider each candidate in turn.  */
  for (ix = 0; ix < num_fns; ix++)
    {
      int jj;
      int static_offset = oload_method_static (method, fns_ptr, ix);
      int nparms;
      struct type **parm_types;

      if (method)
        {
          nparms = TYPE_NFIELDS (TYPE_FN_FIELD_TYPE (fns_ptr, ix));
        }
      else
        {
          /* If it's not a method, this is the proper place.  */
          nparms = TYPE_NFIELDS (SYMBOL_TYPE (oload_syms[ix]));
        }

      /* Prepare array of parameter types.  */
      parm_types = (struct type **) 
        xmalloc (nparms * (sizeof (struct type *)));
      for (jj = 0; jj < nparms; jj++)
        parm_types[jj] = (method
                          ? (TYPE_FN_FIELD_ARGS (fns_ptr, ix)[jj].type)
                          : TYPE_FIELD_TYPE (SYMBOL_TYPE (oload_syms[ix]), 
                                             jj));

      /* Compare parameter types to supplied argument types.  Skip
         THIS for static methods.  */
      bv = rank_function (parm_types, nparms, 
                          arg_types + static_offset,
                          nargs - static_offset);

      if (!*oload_champ_bv)
        {
          *oload_champ_bv = bv;
          oload_champ = 0;
        }
      else /* See whether current candidate is better or worse than
              previous best.  */
        switch (compare_badness (bv, *oload_champ_bv))
          {
          case 0:               /* Top two contenders are equally good.  */
            oload_ambiguous = 1;
            break;
          case 1:               /* Incomparable top contenders.  */
            oload_ambiguous = 2;
            break;
          case 2:               /* New champion, record details.  */
            *oload_champ_bv = bv;
            oload_ambiguous = 0;
            oload_champ = ix;
            break;
          case 3:
          default:
            break;
          }
      xfree (parm_types);
      if (overload_debug)
        {
          if (method)
            fprintf_filtered (gdb_stderr,
                              "Overloaded method instance %s, # of parms %d\n", 
                              fns_ptr[ix].physname, nparms);
          else
            fprintf_filtered (gdb_stderr,
                              "Overloaded function instance %s # of parms %d\n",
                              SYMBOL_DEMANGLED_NAME (oload_syms[ix]), 
                              nparms);
          for (jj = 0; jj < nargs - static_offset; jj++)
            fprintf_filtered (gdb_stderr,
                              "...Badness @ %d : %d\n", 
                              jj, bv->rank[jj]);
          fprintf_filtered (gdb_stderr,
                            "Overload resolution champion is %d, ambiguous? %d\n", 
                            oload_champ, oload_ambiguous);
        }
    }

  return oload_champ;
}

/* Return 1 if we're looking at a static method, 0 if we're looking at
   a non-static method or a function that isn't a method.  */

static int
oload_method_static (int method, struct fn_field *fns_ptr, int index)
{
  if (method && TYPE_FN_FIELD_STATIC_P (fns_ptr, index))
    return 1;
  else
    return 0;
}

/* Check how good an overload match OLOAD_CHAMP_BV represents.  */

static enum oload_classification
classify_oload_match (struct badness_vector *oload_champ_bv,
                      int nargs,
                      int static_offset)
{
  int ix;

  for (ix = 1; ix <= nargs - static_offset; ix++)
    {
      if (oload_champ_bv->rank[ix] >= 100)
        return INCOMPATIBLE;    /* Truly mismatched types.  */
      else if (oload_champ_bv->rank[ix] >= 10)
        return NON_STANDARD;    /* Non-standard type conversions
                                   needed.  */
    }

  return STANDARD;              /* Only standard conversions needed.  */
}

/* C++: return 1 is NAME is a legitimate name for the destructor of
   type TYPE.  If TYPE does not have a destructor, or if NAME is
   inappropriate for TYPE, an error is signaled.  */
int
destructor_name_p (const char *name, const struct type *type)
{
  if (name[0] == '~')
    {
      char *dname = type_name_no_tag (type);
      char *cp = strchr (dname, '<');
      unsigned int len;

      /* Do not compare the template part for template classes.  */
      if (cp == NULL)
        len = strlen (dname);
      else
        len = cp - dname;
      if (strlen (name + 1) != len || strncmp (dname, name + 1, len) != 0)
        error (_("name of destructor must equal name of class"));
      else
        return 1;
    }
  return 0;
}

/* Given TYPE, a structure/union,
   return 1 if the component named NAME from the ultimate target
   structure/union is defined, otherwise, return 0.  */

int
check_field (struct type *type, const char *name)
{
  int i;

  for (i = TYPE_NFIELDS (type) - 1; i >= TYPE_N_BASECLASSES (type); i--)
    {
      char *t_field_name = TYPE_FIELD_NAME (type, i);
      if (t_field_name && (strcmp_iw (t_field_name, name) == 0))
        return 1;
    }

  /* C++: If it was not found as a data field, then try to return it
     as a pointer to a method.  */

  for (i = TYPE_NFN_FIELDS (type) - 1; i >= 0; --i)
    {
      if (strcmp_iw (TYPE_FN_FIELDLIST_NAME (type, i), name) == 0)
        return 1;
    }

  for (i = TYPE_N_BASECLASSES (type) - 1; i >= 0; i--)
    if (check_field (TYPE_BASECLASS (type, i), name))
      return 1;

  return 0;
}

/* C++: Given an aggregate type CURTYPE, and a member name NAME,
   return the appropriate member (or the address of the member, if
   WANT_ADDRESS).  This function is used to resolve user expressions
   of the form "DOMAIN::NAME".  For more details on what happens, see
   the comment before value_struct_elt_for_reference.  */

struct value *
value_aggregate_elt (struct type *curtype,
                     char *name, int want_address,
                     enum noside noside)
{
  switch (TYPE_CODE (curtype))
    {
    case TYPE_CODE_STRUCT:
    case TYPE_CODE_UNION:
      return value_struct_elt_for_reference (curtype, 0, curtype, 
                                             name, NULL,
                                             want_address, noside);
    case TYPE_CODE_NAMESPACE:
      return value_namespace_elt (curtype, name, 
                                  want_address, noside);
    default:
      internal_error (__FILE__, __LINE__,
                      _("non-aggregate type in value_aggregate_elt"));
    }
}

/* C++: Given an aggregate type CURTYPE, and a member name NAME,
   return the address of this member as a "pointer to member" type.
   If INTYPE is non-null, then it will be the type of the member we
   are looking for.  This will help us resolve "pointers to member
   functions".  This function is used to resolve user expressions of
   the form "DOMAIN::NAME".  */

static struct value *
value_struct_elt_for_reference (struct type *domain, int offset,
                                struct type *curtype, char *name,
                                struct type *intype, 
                                int want_address,
                                enum noside noside)
{
  struct type *t = curtype;
  int i;
  struct value *v, *result;

  if (TYPE_CODE (t) != TYPE_CODE_STRUCT
      && TYPE_CODE (t) != TYPE_CODE_UNION)
    error (_("Internal error: non-aggregate type to value_struct_elt_for_reference"));

  for (i = TYPE_NFIELDS (t) - 1; i >= TYPE_N_BASECLASSES (t); i--)
    {
      char *t_field_name = TYPE_FIELD_NAME (t, i);

      if (t_field_name && strcmp (t_field_name, name) == 0)
        {
          if (field_is_static (&TYPE_FIELD (t, i)))
            {
              v = value_static_field (t, i);
              if (v == NULL)
                error (_("static field %s has been optimized out"),
                       name);
              if (want_address)
                v = value_addr (v);
              return v;
            }
          if (TYPE_FIELD_PACKED (t, i))
            error (_("pointers to bitfield members not allowed"));

          if (want_address)
            return value_from_longest
              (lookup_memberptr_type (TYPE_FIELD_TYPE (t, i), domain),
               offset + (LONGEST) (TYPE_FIELD_BITPOS (t, i) >> 3));
          else if (noside == EVAL_AVOID_SIDE_EFFECTS)
            return allocate_value (TYPE_FIELD_TYPE (t, i));
          else
            error (_("Cannot reference non-static field \"%s\""), name);
        }
    }

  /* C++: If it was not found as a data field, then try to return it
     as a pointer to a method.  */

  /* Perform all necessary dereferencing.  */
  while (intype && TYPE_CODE (intype) == TYPE_CODE_PTR)
    intype = TYPE_TARGET_TYPE (intype);

  for (i = TYPE_NFN_FIELDS (t) - 1; i >= 0; --i)
    {
      char *t_field_name = TYPE_FN_FIELDLIST_NAME (t, i);
      char dem_opname[64];

      if (strncmp (t_field_name, "__", 2) == 0 
          || strncmp (t_field_name, "op", 2) == 0 
          || strncmp (t_field_name, "type", 4) == 0)
        {
          if (cplus_demangle_opname (t_field_name, 
                                     dem_opname, DMGL_ANSI))
            t_field_name = dem_opname;
          else if (cplus_demangle_opname (t_field_name, 
                                          dem_opname, 0))
            t_field_name = dem_opname;
        }
      if (t_field_name && strcmp (t_field_name, name) == 0)
        {
          int j = TYPE_FN_FIELDLIST_LENGTH (t, i);
          struct fn_field *f = TYPE_FN_FIELDLIST1 (t, i);

          check_stub_method_group (t, i);

          if (intype == 0 && j > 1)
            error (_("non-unique member `%s' requires type instantiation"), name);
          if (intype)
            {
              while (j--)
                if (TYPE_FN_FIELD_TYPE (f, j) == intype)
                  break;
              if (j < 0)
                error (_("no member function matches that type instantiation"));
            }
          else
            j = 0;

          if (TYPE_FN_FIELD_STATIC_P (f, j))
            {
              struct symbol *s = 
                lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f, j),
                               0, VAR_DOMAIN, 0);
              if (s == NULL)
                return NULL;

              if (want_address)
                return value_addr (read_var_value (s, 0));
              else
                return read_var_value (s, 0);
            }

          if (TYPE_FN_FIELD_VIRTUAL_P (f, j))
            {
              if (want_address)
                {
                  result = allocate_value
                    (lookup_methodptr_type (TYPE_FN_FIELD_TYPE (f, j)));
                  cplus_make_method_ptr (value_type (result),
                                         value_contents_writeable (result),
                                         TYPE_FN_FIELD_VOFFSET (f, j), 1);
                }
              else if (noside == EVAL_AVOID_SIDE_EFFECTS)
                return allocate_value (TYPE_FN_FIELD_TYPE (f, j));
              else
                error (_("Cannot reference virtual member function \"%s\""),
                       name);
            }
          else
            {
              struct symbol *s = 
                lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f, j),
                               0, VAR_DOMAIN, 0);
              if (s == NULL)
                return NULL;

              v = read_var_value (s, 0);
              if (!want_address)
                result = v;
              else
                {
                  result = allocate_value (lookup_methodptr_type (TYPE_FN_FIELD_TYPE (f, j)));
                  cplus_make_method_ptr (value_type (result),
                                         value_contents_writeable (result),
                                         value_address (v), 0);
                }
            }
          return result;
        }
    }
  for (i = TYPE_N_BASECLASSES (t) - 1; i >= 0; i--)
    {
      struct value *v;
      int base_offset;

      if (BASETYPE_VIA_VIRTUAL (t, i))
        base_offset = 0;
      else
        base_offset = TYPE_BASECLASS_BITPOS (t, i) / 8;
      v = value_struct_elt_for_reference (domain,
                                          offset + base_offset,
                                          TYPE_BASECLASS (t, i),
                                          name, intype, 
                                          want_address, noside);
      if (v)
        return v;
    }

  /* As a last chance, pretend that CURTYPE is a namespace, and look
     it up that way; this (frequently) works for types nested inside
     classes.  */

  return value_maybe_namespace_elt (curtype, name, 
                                    want_address, noside);
}

/* C++: Return the member NAME of the namespace given by the type
   CURTYPE.  */

static struct value *
value_namespace_elt (const struct type *curtype,
                     char *name, int want_address,
                     enum noside noside)
{
  struct value *retval = value_maybe_namespace_elt (curtype, name,
                                                    want_address, 
                                                    noside);

  if (retval == NULL)
    error (_("No symbol \"%s\" in namespace \"%s\"."), 
           name, TYPE_TAG_NAME (curtype));

  return retval;
}

/* A helper function used by value_namespace_elt and
   value_struct_elt_for_reference.  It looks up NAME inside the
   context CURTYPE; this works if CURTYPE is a namespace or if CURTYPE
   is a class and NAME refers to a type in CURTYPE itself (as opposed
   to, say, some base class of CURTYPE).  */

static struct value *
value_maybe_namespace_elt (const struct type *curtype,
                           char *name, int want_address,
                           enum noside noside)
{
  const char *namespace_name = TYPE_TAG_NAME (curtype);
  struct symbol *sym;
  struct value *result;

  sym = cp_lookup_symbol_namespace (namespace_name, name, NULL,
                                    get_selected_block (0), 
                                    VAR_DOMAIN);

  if (sym == NULL)
    return NULL;
  else if ((noside == EVAL_AVOID_SIDE_EFFECTS)
           && (SYMBOL_CLASS (sym) == LOC_TYPEDEF))
    result = allocate_value (SYMBOL_TYPE (sym));
  else
    result = value_of_variable (sym, get_selected_block (0));

  if (result && want_address)
    result = value_addr (result);

  return result;
}

/* Given a pointer value V, find the real (RTTI) type of the object it
   points to.

   Other parameters FULL, TOP, USING_ENC as with value_rtti_type()
   and refer to the values computed for the object pointed to.  */

struct type *
value_rtti_target_type (struct value *v, int *full, 
                        int *top, int *using_enc)
{
  struct value *target;

  target = value_ind (v);

  return value_rtti_type (target, full, top, using_enc);
}

/* Given a value pointed to by ARGP, check its real run-time type, and
   if that is different from the enclosing type, create a new value
   using the real run-time type as the enclosing type (and of the same
   type as ARGP) and return it, with the embedded offset adjusted to
   be the correct offset to the enclosed object.  RTYPE is the type,
   and XFULL, XTOP, and XUSING_ENC are the other parameters, computed
   by value_rtti_type().  If these are available, they can be supplied
   and a second call to value_rtti_type() is avoided.  (Pass RTYPE ==
   NULL if they're not available.  */

struct value *
value_full_object (struct value *argp, 
                   struct type *rtype, 
                   int xfull, int xtop,
                   int xusing_enc)
{
  struct type *real_type;
  int full = 0;
  int top = -1;
  int using_enc = 0;
  struct value *new_val;

  if (rtype)
    {
      real_type = rtype;
      full = xfull;
      top = xtop;
      using_enc = xusing_enc;
    }
  else
    real_type = value_rtti_type (argp, &full, &top, &using_enc);

  /* If no RTTI data, or if object is already complete, do nothing.  */
  if (!real_type || real_type == value_enclosing_type (argp))
    return argp;

  /* If we have the full object, but for some reason the enclosing
     type is wrong, set it.  */
  /* pai: FIXME -- sounds iffy */
  if (full)
    {
      argp = value_change_enclosing_type (argp, real_type);
      return argp;
    }

  /* Check if object is in memory */
  if (VALUE_LVAL (argp) != lval_memory)
    {
      warning (_("Couldn't retrieve complete object of RTTI type %s; object may be in register(s)."), 
               TYPE_NAME (real_type));

      return argp;
    }

  /* All other cases -- retrieve the complete object.  */
  /* Go back by the computed top_offset from the beginning of the
     object, adjusting for the embedded offset of argp if that's what
     value_rtti_type used for its computation.  */
  new_val = value_at_lazy (real_type, value_address (argp) - top +
                           (using_enc ? 0 : value_embedded_offset (argp)));
  deprecated_set_value_type (new_val, value_type (argp));
  set_value_embedded_offset (new_val, (using_enc
                                       ? top + value_embedded_offset (argp)
                                       : top));
  return new_val;
}


/* Return the value of the local variable, if one exists.
   Flag COMPLAIN signals an error if the request is made in an
   inappropriate context.  */

struct value *
value_of_local (const char *name, int complain)
{
  struct symbol *func, *sym;
  struct block *b;
  struct value * ret;
  struct frame_info *frame;

  if (complain)
    frame = get_selected_frame (_("no frame selected"));
  else
    {
      frame = deprecated_safe_get_selected_frame ();
      if (frame == 0)
        return 0;
    }

  func = get_frame_function (frame);
  if (!func)
    {
      if (complain)
        error (_("no `%s' in nameless context"), name);
      else
        return 0;
    }

  b = SYMBOL_BLOCK_VALUE (func);
  if (dict_empty (BLOCK_DICT (b)))
    {
      if (complain)
        error (_("no args, no `%s'"), name);
      else
        return 0;
    }

  /* Calling lookup_block_symbol is necessary to get the LOC_REGISTER
     symbol instead of the LOC_ARG one (if both exist).  */
  sym = lookup_block_symbol (b, name, NULL, VAR_DOMAIN);
  if (sym == NULL)
    {
      if (complain)
        error (_("current stack frame does not contain a variable named `%s'"), 
               name);
      else
        return NULL;
    }

  ret = read_var_value (sym, frame);
  if (ret == 0 && complain)
    error (_("`%s' argument unreadable"), name);
  return ret;
}

/* C++/Objective-C: return the value of the class instance variable,
   if one exists.  Flag COMPLAIN signals an error if the request is
   made in an inappropriate context.  */

struct value *
value_of_this (int complain)
{
  if (!current_language->la_name_of_this)
    return 0;
  return value_of_local (current_language->la_name_of_this, complain);
}

/* Create a slice (sub-string, sub-array) of ARRAY, that is LENGTH
   elements long, starting at LOWBOUND.  The result has the same lower
   bound as the original ARRAY.  */

struct value *
value_slice (struct value *array, int lowbound, int length)
{
  struct type *slice_range_type, *slice_type, *range_type;
  LONGEST lowerbound, upperbound;
  struct value *slice;
  struct type *array_type;

  array_type = check_typedef (value_type (array));
  if (TYPE_CODE (array_type) != TYPE_CODE_ARRAY
      && TYPE_CODE (array_type) != TYPE_CODE_STRING
      && TYPE_CODE (array_type) != TYPE_CODE_BITSTRING)
    error (_("cannot take slice of non-array"));

  range_type = TYPE_INDEX_TYPE (array_type);
  if (get_discrete_bounds (range_type, &lowerbound, &upperbound) < 0)
    error (_("slice from bad array or bitstring"));

  if (lowbound < lowerbound || length < 0
      || lowbound + length - 1 > upperbound)
    error (_("slice out of range"));

  /* FIXME-type-allocation: need a way to free this type when we are
     done with it.  */
  slice_range_type = create_range_type ((struct type *) NULL,
                                        TYPE_TARGET_TYPE (range_type),
                                        lowbound, 
                                        lowbound + length - 1);
  if (TYPE_CODE (array_type) == TYPE_CODE_BITSTRING)
    {
      int i;

      slice_type = create_set_type ((struct type *) NULL,
                                    slice_range_type);
      TYPE_CODE (slice_type) = TYPE_CODE_BITSTRING;
      slice = value_zero (slice_type, not_lval);

      for (i = 0; i < length; i++)
        {
          int element = value_bit_index (array_type,
                                         value_contents (array),
                                         lowbound + i);
          if (element < 0)
            error (_("internal error accessing bitstring"));
          else if (element > 0)
            {
              int j = i % TARGET_CHAR_BIT;
              if (gdbarch_bits_big_endian (get_type_arch (array_type)))
                j = TARGET_CHAR_BIT - 1 - j;
              value_contents_raw (slice)[i / TARGET_CHAR_BIT] |= (1 << j);
            }
        }
      /* We should set the address, bitssize, and bitspos, so the
         slice can be used on the LHS, but that may require extensions
         to value_assign.  For now, just leave as a non_lval.
         FIXME.  */
    }
  else
    {
      struct type *element_type = TYPE_TARGET_TYPE (array_type);
      LONGEST offset =
        (lowbound - lowerbound) * TYPE_LENGTH (check_typedef (element_type));

      slice_type = create_array_type ((struct type *) NULL, 
                                      element_type,
                                      slice_range_type);
      TYPE_CODE (slice_type) = TYPE_CODE (array_type);

      if (VALUE_LVAL (array) == lval_memory && value_lazy (array))
        slice = allocate_value_lazy (slice_type);
      else
        {
          slice = allocate_value (slice_type);
          memcpy (value_contents_writeable (slice),
                  value_contents (array) + offset,
                  TYPE_LENGTH (slice_type));
        }

      set_value_component_location (slice, array);
      VALUE_FRAME_ID (slice) = VALUE_FRAME_ID (array);
      set_value_offset (slice, value_offset (array) + offset);
    }
  return slice;
}

/* Create a value for a FORTRAN complex number.  Currently most of the
   time values are coerced to COMPLEX*16 (i.e. a complex number
   composed of 2 doubles.  This really should be a smarter routine
   that figures out precision inteligently as opposed to assuming
   doubles.  FIXME: fmb  */

struct value *
value_literal_complex (struct value *arg1, 
                       struct value *arg2,
                       struct type *type)
{
  struct value *val;
  struct type *real_type = TYPE_TARGET_TYPE (type);

  val = allocate_value (type);
  arg1 = value_cast (real_type, arg1);
  arg2 = value_cast (real_type, arg2);

  memcpy (value_contents_raw (val),
          value_contents (arg1), TYPE_LENGTH (real_type));
  memcpy (value_contents_raw (val) + TYPE_LENGTH (real_type),
          value_contents (arg2), TYPE_LENGTH (real_type));
  return val;
}

/* Cast a value into the appropriate complex data type.  */

static struct value *
cast_into_complex (struct type *type, struct value *val)
{
  struct type *real_type = TYPE_TARGET_TYPE (type);

  if (TYPE_CODE (value_type (val)) == TYPE_CODE_COMPLEX)
    {
      struct type *val_real_type = TYPE_TARGET_TYPE (value_type (val));
      struct value *re_val = allocate_value (val_real_type);
      struct value *im_val = allocate_value (val_real_type);

      memcpy (value_contents_raw (re_val),
              value_contents (val), TYPE_LENGTH (val_real_type));
      memcpy (value_contents_raw (im_val),
              value_contents (val) + TYPE_LENGTH (val_real_type),
              TYPE_LENGTH (val_real_type));

      return value_literal_complex (re_val, im_val, type);
    }
  else if (TYPE_CODE (value_type (val)) == TYPE_CODE_FLT
           || TYPE_CODE (value_type (val)) == TYPE_CODE_INT)
    return value_literal_complex (val, 
                                  value_zero (real_type, not_lval), 
                                  type);
  else
    error (_("cannot cast non-number to complex"));
}

void
_initialize_valops (void)
{
  add_setshow_boolean_cmd ("overload-resolution", class_support,
                           &overload_resolution, _("\
Set overload resolution in evaluating C++ functions."), _("\
Show overload resolution in evaluating C++ functions."), 
                           NULL, NULL,
                           show_overload_resolution,
                           &setlist, &showlist);
  overload_resolution = 1;
}