/* Functions related to invoking methods and overloaded functions.
   Copyright (C) 1987, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
   Contributed by Michael Tiemann (tiemann@cygnus.com) and
   hacked by Brendan Kehoe (brendan@cygnus.com).

This file is part of GNU CC.

GNU CC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU CC 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 GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */


/* High-level class interface. */

#include "config.h"
#include "tree.h"
#include <stdio.h>
#include "cp-tree.h"
#include "class.h"
#include "output.h"
#include "flags.h"

#include "obstack.h"
#define obstack_chunk_alloc xmalloc
#define obstack_chunk_free free

extern void sorry ();

extern int inhibit_warnings;
extern tree ctor_label, dtor_label;

/* Compute the ease with which a conversion can be performed
   between an expected and the given type.  */
static struct harshness_code convert_harshness PROTO((register tree, register tree, tree));

#define EVIL_RETURN(ARG)	((ARG).code = EVIL_CODE, (ARG))
#define STD_RETURN(ARG)		((ARG).code = STD_CODE, (ARG))
#define QUAL_RETURN(ARG)	((ARG).code = QUAL_CODE, (ARG))
#define TRIVIAL_RETURN(ARG)	((ARG).code = TRIVIAL_CODE, (ARG))
#define ZERO_RETURN(ARG)	((ARG).code = 0, (ARG))

/* Ordering function for overload resolution.  Compare two candidates
   by gross quality.  */
int
rank_for_overload (x, y)
     struct candidate *x, *y;
{
  if (y->h.code & (EVIL_CODE|ELLIPSIS_CODE|USER_CODE))
    return y->h.code - x->h.code;
  if (x->h.code & (EVIL_CODE|ELLIPSIS_CODE|USER_CODE))
    return -1;

  /* This is set by compute_conversion_costs, for calling a non-const
     member function from a const member function.  */
  if ((y->harshness[0].code & CONST_CODE) ^ (x->harshness[0].code & CONST_CODE))
    return y->harshness[0].code - x->harshness[0].code;

  if (y->h.code & STD_CODE)
    {
      if (x->h.code & STD_CODE)
	return y->h.distance - x->h.distance;
      return 1;
    }
  if (x->h.code & STD_CODE)
    return -1;

  return y->h.code - x->h.code;
}

/* Compare two candidates, argument by argument.  */
int
rank_for_ideal (x, y)
     struct candidate *x, *y;
{
  int i;

  if (x->h_len != y->h_len)
    abort ();

  for (i = 0; i < x->h_len; i++)
    {
      if (y->harshness[i].code - x->harshness[i].code)
	return y->harshness[i].code - x->harshness[i].code;
      if ((y->harshness[i].code & STD_CODE)
	  && (y->harshness[i].distance - x->harshness[i].distance))
	return y->harshness[i].distance - x->harshness[i].distance;

      /* They're both the same code.  Now see if we're dealing with an
	 integral promotion that needs a finer grain of accuracy.  */
      if (y->harshness[0].code & PROMO_CODE
	  && (y->harshness[i].int_penalty ^ x->harshness[i].int_penalty))
	return y->harshness[i].int_penalty - x->harshness[i].int_penalty;
    }
  return 0;
}

/* TYPE is the type we wish to convert to.  PARM is the parameter
   we have to work with.  We use a somewhat arbitrary cost function
   to measure this conversion.  */
static struct harshness_code
convert_harshness (type, parmtype, parm)
     register tree type, parmtype;
     tree parm;
{
  struct harshness_code h;
  register enum tree_code codel;
  register enum tree_code coder;
  int lvalue;

  h.code = 0;
  h.distance = 0;
  h.int_penalty = 0;

#ifdef GATHER_STATISTICS
  n_convert_harshness++;
#endif

  if (TREE_CODE (parmtype) == REFERENCE_TYPE)
    {
      if (parm)
	parm = convert_from_reference (parm);
      parmtype = TREE_TYPE (parmtype);
      lvalue = 1;
    }
  else if (parm)
    lvalue = lvalue_p (parm);
  else
    lvalue = 0;

  if (TYPE_PTRMEMFUNC_P (type))
    type = TYPE_PTRMEMFUNC_FN_TYPE (type);
  if (TYPE_PTRMEMFUNC_P (parmtype))
    parmtype = TYPE_PTRMEMFUNC_FN_TYPE (parmtype);

  codel = TREE_CODE (type);
  coder = TREE_CODE (parmtype);

  if (TYPE_MAIN_VARIANT (parmtype) == TYPE_MAIN_VARIANT (type))
    return ZERO_RETURN (h);

  if (coder == ERROR_MARK)
    return EVIL_RETURN (h);

  if (codel == REFERENCE_TYPE)
    {
      tree ttl, ttr;
      int constp = parm ? TREE_READONLY (parm) : TYPE_READONLY (parmtype);
      int volatilep = (parm ? TREE_THIS_VOLATILE (parm)
		       : TYPE_VOLATILE (parmtype));
      register tree intype = TYPE_MAIN_VARIANT (parmtype);
      register enum tree_code form = TREE_CODE (intype);
      int penalty = 0;

      ttl = TREE_TYPE (type);

      /* Only allow const reference binding if we were given a parm to deal
         with, since it isn't really a conversion.  This is a hack to
         prevent build_type_conversion from finding this conversion, but
         still allow overloading to find it.  */
      if (! lvalue && ! (parm && TYPE_READONLY (ttl)))
	return EVIL_RETURN (h);

      if ((TYPE_READONLY (ttl) < constp)
	  || (TYPE_VOLATILE (ttl) < volatilep))
	return EVIL_RETURN (h);

      /* When passing a non-const argument into a const reference, dig it a
	 little, so a non-const reference is preferred over this one.  */
      penalty = ((TYPE_READONLY (ttl) > constp)
		 + (TYPE_VOLATILE (ttl) > volatilep));

      ttl = TYPE_MAIN_VARIANT (ttl);

      if (form == OFFSET_TYPE)
	{
	  intype = TREE_TYPE (intype);
	  form = TREE_CODE (intype);
	}

      ttr = intype;

      if (TREE_CODE (ttl) == ARRAY_TYPE && TREE_CODE (ttr) == ARRAY_TYPE)
	{
	  if (comptypes (ttl, ttr, 1))
	    return ZERO_RETURN (h);
	  return EVIL_RETURN (h);
	}

      h = convert_harshness (ttl, ttr, NULL_TREE);
      if (penalty && h.code == 0)
	{
	  h.code = QUAL_CODE;
	  h.int_penalty = penalty;
	}
      return h;
    }

  if (codel == POINTER_TYPE && fntype_p (parmtype))
    {
      tree p1, p2;
      struct harshness_code h1, h2;

      /* Get to the METHOD_TYPE or FUNCTION_TYPE that this might be.  */
      type = TREE_TYPE (type);

      if (coder == POINTER_TYPE)
	{
	  parmtype = TREE_TYPE (parmtype);
	  coder = TREE_CODE (parmtype);
	}

      if (coder != TREE_CODE (type))
	return EVIL_RETURN (h);

      if (type != parmtype && coder == METHOD_TYPE)
	{
	  tree ttl = TYPE_METHOD_BASETYPE (type);
	  tree ttr = TYPE_METHOD_BASETYPE (parmtype);

	  int b_or_d = get_base_distance (ttr, ttl, 0, 0);
	  if (b_or_d < 0)
	    {
	      b_or_d = get_base_distance (ttl, ttr, 0, 0);
	      if (b_or_d < 0)
		return EVIL_RETURN (h);
	      h.distance = -b_or_d;
	    }
	  else
	    h.distance = b_or_d;
	  h.code = STD_CODE;

	  type = build_function_type
	    (TREE_TYPE (type), TREE_CHAIN (TYPE_ARG_TYPES (type)));
	  parmtype = build_function_type
	    (TREE_TYPE (parmtype), TREE_CHAIN (TYPE_ARG_TYPES (parmtype)));
	}

      /* We allow the default conversion between function type
	 and pointer-to-function type for free.  */
      if (comptypes (type, parmtype, 1))
	return h;

      if (pedantic)
	return EVIL_RETURN (h);

      /* Compare return types.  */
      p1 = TREE_TYPE (type);
      p2 = TREE_TYPE (parmtype);
      h2 = convert_harshness (p1, p2, NULL_TREE);
      if (h2.code & EVIL_CODE)
	return h2;

      h1.code = TRIVIAL_CODE;
      h1.distance = 0;

      if (h2.distance != 0)
	{
	  tree binfo;

	  /* This only works for pointers.  */
	  if (TREE_CODE (p1) != POINTER_TYPE
	      && TREE_CODE (p1) != REFERENCE_TYPE)
	    return EVIL_RETURN (h);

	  p1 = TREE_TYPE (p1);
	  p2 = TREE_TYPE (p2);
	  /* Don't die if we happen to be dealing with void*.  */
	  if (!IS_AGGR_TYPE (p1) || !IS_AGGR_TYPE (p2))
	    return EVIL_RETURN (h);
	  if (h2.distance < 0)
	    binfo = get_binfo (p2, p1, 0);
	  else
	    binfo = get_binfo (p1, p2, 0);

	  if (! BINFO_OFFSET_ZEROP (binfo))
	    {
#if 0
	      static int explained = 0;
	      if (h2.distance < 0)
		message_2_types (sorry, "cannot cast `%s' to `%s' at function call site", p2, p1);
	      else
		message_2_types (sorry, "cannot cast `%s' to `%s' at function call site", p1, p2);

	      if (! explained++)
		sorry ("(because pointer values change during conversion)");
#endif
	      return EVIL_RETURN (h);
	    }
	}

      h1.code |= h2.code;
      if (h2.distance > h1.distance)
	h1.distance = h2.distance;

      p1 = TYPE_ARG_TYPES (type);
      p2 = TYPE_ARG_TYPES (parmtype);
      while (p1 && TREE_VALUE (p1) != void_type_node
	     && p2 && TREE_VALUE (p2) != void_type_node)
	{
	  h2 = convert_harshness (TREE_VALUE (p1), TREE_VALUE (p2),
				       NULL_TREE);
	  if (h2.code & EVIL_CODE)
	    return h2;

	  if (h2.distance)
	    {
	      /* This only works for pointers and references. */
	      if (TREE_CODE (TREE_VALUE (p1)) != POINTER_TYPE
		  && TREE_CODE (TREE_VALUE (p1)) != REFERENCE_TYPE)
		return EVIL_RETURN (h);
	      h2.distance = - h2.distance;
	    }

	  h1.code |= h2.code;
	  if (h2.distance > h1.distance)
	    h1.distance = h2.distance;
	  p1 = TREE_CHAIN (p1);
	  p2 = TREE_CHAIN (p2);
	}
      if (p1 == p2)
	return h1;
      if (p2)
	{
	  if (p1)
	    return EVIL_RETURN (h);
	  h1.code |= ELLIPSIS_CODE;
	  return h1;
	}
      if (p1)
	{
	  if (TREE_PURPOSE (p1) == NULL_TREE)
	    h1.code |= EVIL_CODE;
	  return h1;
	}
    }
  else if (codel == POINTER_TYPE && coder == OFFSET_TYPE)
    {
      tree ttl, ttr;

      /* Get to the OFFSET_TYPE that this might be.  */
      type = TREE_TYPE (type);

      if (coder != TREE_CODE (type))
	return EVIL_RETURN (h);

      ttl = TYPE_OFFSET_BASETYPE (type);
      ttr = TYPE_OFFSET_BASETYPE (parmtype);

      if (ttl == ttr)
	h.code = 0;
      else
	{
	  int b_or_d = get_base_distance (ttr, ttl, 0, 0);
	  if (b_or_d < 0)
	    {
	      b_or_d = get_base_distance (ttl, ttr, 0, 0);
	      if (b_or_d < 0)
		return EVIL_RETURN (h);
	      h.distance = -b_or_d;
	    }
	  else
	    h.distance = b_or_d;
	  h.code = STD_CODE;
	}

      /* Now test the OFFSET_TYPE's target compatibility.  */
      type = TREE_TYPE (type);
      parmtype = TREE_TYPE (parmtype);
    }

  if (coder == UNKNOWN_TYPE)
    {
      if (codel == FUNCTION_TYPE
	  || codel == METHOD_TYPE
	  || (codel == POINTER_TYPE
	      && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
		  || TREE_CODE (TREE_TYPE (type)) == METHOD_TYPE)))
	return TRIVIAL_RETURN (h);
      return EVIL_RETURN (h);
    }

  if (coder == VOID_TYPE)
    return EVIL_RETURN (h);

  if (codel == BOOLEAN_TYPE)
    {
      if (INTEGRAL_CODE_P (coder) || coder == REAL_TYPE)
	return STD_RETURN (h);
      else if (coder == POINTER_TYPE || coder == OFFSET_TYPE)
	{
	  /* Make this worse than any conversion to another pointer.
	     FIXME this is how I think the language should work, but it may not
	     end up being how the language is standardized (jason 1/30/95).  */
	  h.distance = 32767;
	  return STD_RETURN (h);
	}
      return EVIL_RETURN (h);
    }

  if (INTEGRAL_CODE_P (codel))
    {
      /* Control equivalence of ints an enums.  */

      if (codel == ENUMERAL_TYPE
	  && flag_int_enum_equivalence == 0)
	{
	  /* Enums can be converted to ints, but not vice-versa.  */
	  if (coder != ENUMERAL_TYPE
	      || TYPE_MAIN_VARIANT (type) != TYPE_MAIN_VARIANT (parmtype))
	    return EVIL_RETURN (h);
	}

      /* else enums and ints (almost) freely interconvert.  */

      if (INTEGRAL_CODE_P (coder))
	{
	  if (TYPE_MAIN_VARIANT (type)
	      == TYPE_MAIN_VARIANT (type_promotes_to (parmtype)))
	    {
	      h.code = PROMO_CODE;
	    }
	  else
	    h.code = STD_CODE;
	    
	  return h;
	}
      else if (coder == REAL_TYPE)
	{
	  h.code = STD_CODE;
	  h.distance = 0;
	  return h;
	}
    }

  if (codel == REAL_TYPE)
    {
      if (coder == REAL_TYPE)
	{
	  if (TYPE_MAIN_VARIANT (type)
	      == TYPE_MAIN_VARIANT (type_promotes_to (parmtype)))
	    h.code = PROMO_CODE;
	  else
	    h.code = STD_CODE;
	    
	  return h;
	}
      else if (INTEGRAL_CODE_P (coder))
	{
	  h.code = STD_CODE;
	  h.distance = 0;
	  return h;
	}
    }

  /* Convert arrays which have not previously been converted.  */
  if (coder == ARRAY_TYPE)
    {
      coder = POINTER_TYPE;
      if (parm)
	{
	  parm = decay_conversion (parm);
	  parmtype = TREE_TYPE (parm);
	}
      else
	parmtype = build_pointer_type (TREE_TYPE (parmtype));
    }

  /* Conversions among pointers */
  if (codel == POINTER_TYPE && coder == POINTER_TYPE)
    {
      register tree ttl = TYPE_MAIN_VARIANT (TREE_TYPE (type));
      register tree ttr = TYPE_MAIN_VARIANT (TREE_TYPE (parmtype));
      int penalty = 4 * (ttl != ttr);

      /* Anything converts to void *.  Since this may be `const void *'
	 (etc.) use VOID_TYPE instead of void_type_node.  Otherwise, the
	 targets must be the same, except that we do allow (at some cost)
	 conversion between signed and unsigned pointer types.  */

      if ((TREE_CODE (ttl) == METHOD_TYPE
	   || TREE_CODE (ttl) == FUNCTION_TYPE)
	  && TREE_CODE (ttl) == TREE_CODE (ttr))
	{
	  if (comptypes (ttl, ttr, -1))
	    {
	      h.code = penalty ? STD_CODE : 0;
	      h.distance =  0;
	    }
	  else
	    h.code = EVIL_CODE;
	  return h;
	}

#if 1
      if (TREE_CODE (ttl) != VOID_TYPE
	  && (TREE_CODE (ttr) != VOID_TYPE || !parm || !integer_zerop (parm)))
	{
	  if (TREE_UNSIGNED (ttl) != TREE_UNSIGNED (ttr))
	    {
	      ttl = unsigned_type (ttl);
	      ttr = unsigned_type (ttr);
	      penalty = 10;
	    }
	  if (comp_target_types (type, parmtype, 1) <= 0)
	    return EVIL_RETURN (h);
	}
#else
      if (!(TREE_CODE (ttl) == VOID_TYPE
	    || TREE_CODE (ttr) == VOID_TYPE
	    || (TREE_UNSIGNED (ttl) ^ TREE_UNSIGNED (ttr)
		&& (ttl = unsigned_type (ttl),
		    ttr = unsigned_type (ttr),
		    penalty = 10, 0))
	    || (comp_target_types (ttl, ttr, 0) > 0)))
	return EVIL_RETURN (h);
#endif

      if (penalty == 10 || ttr == ttl)
	{
	  tree tmp1 = TREE_TYPE (type), tmp2 = TREE_TYPE (parmtype);

	  /* If one was unsigned but the other wasn't, then we need to
	     do a standard conversion from T to unsigned T.  */
	  if (penalty == 10)
	    h.code = PROMO_CODE; /* was STD_CODE */
	  else
	    h.code = 0;

	  /* Note conversion from `T*' to `const T*',
	                       or `T*' to `volatile T*'.  */
	  if (ttl == ttr
	      && ((TYPE_READONLY (tmp1) != TREE_READONLY (tmp2))
		  || (TYPE_VOLATILE (tmp1) != TYPE_VOLATILE (tmp2))))
	    h.code |= QUAL_CODE;

	  h.distance = 0;
	  return h;
	}


      if (TREE_CODE (ttl) == RECORD_TYPE && TREE_CODE (ttr) == RECORD_TYPE)
	{
	  int b_or_d = get_base_distance (ttl, ttr, 0, 0);
	  if (b_or_d < 0)
	    {
	      b_or_d = get_base_distance (ttr, ttl, 0, 0);
	      if (b_or_d < 0)
		return EVIL_RETURN (h);
	      h.distance = -b_or_d;
	    }
	  else
	    h.distance = b_or_d;
	  h.code = STD_CODE;
	  return h;
	}

      /* If converting from a `class*' to a `void*', make it
	 less favorable than any inheritance relationship.  */
      if (TREE_CODE (ttl) == VOID_TYPE && IS_AGGR_TYPE (ttr))
	{
	  h.code = STD_CODE;
	  h.distance = CLASSTYPE_MAX_DEPTH (ttr)+1;
	  return h;
	}

      h.code = penalty ? STD_CODE : PROMO_CODE;
      /* Catch things like `const char *' -> `const void *'
	 vs `const char *' -> `void *'.  */
      if (ttl != ttr)
	{
	  tree tmp1 = TREE_TYPE (type), tmp2 = TREE_TYPE (parmtype);
	  if ((TYPE_READONLY (tmp1) != TREE_READONLY (tmp2))
	      || (TYPE_VOLATILE (tmp1) != TYPE_VOLATILE (tmp2)))
	    h.code |= QUAL_CODE;
	}
      return h;
    }

  if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
    {
      /* This is not a bad match, but don't let it beat
	 integer-enum combinations.  */
      if (parm && integer_zerop (parm))
	{
	  h.code = STD_CODE;
	  h.distance = 0;
	  return h;
	}
    }

  /* C++: Since the `this' parameter of a signature member function
     is represented as a signature pointer to handle default implementations
     correctly, we can have the case that `type' is a signature pointer
     while `parmtype' is a pointer to a signature table.  We don't really
     do any conversions in this case, so just return 0.  */

  if (codel == RECORD_TYPE && coder == POINTER_TYPE
      && IS_SIGNATURE_POINTER (type) && IS_SIGNATURE (TREE_TYPE (parmtype)))
    return ZERO_RETURN (h);

  if (codel == RECORD_TYPE && coder == RECORD_TYPE)
    {
      int b_or_d = get_base_distance (type, parmtype, 0, 0);
      if (b_or_d < 0)
	{
	  b_or_d = get_base_distance (parmtype, type, 0, 0);
	  if (b_or_d < 0)
	    return EVIL_RETURN (h);
	  h.distance = -b_or_d;
	}
      else
	h.distance = b_or_d;
      h.code = STD_CODE;
      return h;
    }
  return EVIL_RETURN (h);
}

/* A clone of build_type_conversion for checking user-defined conversions in
   overload resolution.  */

int
user_harshness (type, parmtype)
     register tree type, parmtype;
{
  tree conv;
  tree winner = NULL_TREE;
  int code;

  {
    tree typename = build_typename_overload (type);
    if (lookup_fnfields (TYPE_BINFO (parmtype), typename, 0))
      return 0;
  }
			
  for (conv = lookup_conversions (parmtype); conv; conv = TREE_CHAIN (conv))
    {
      struct harshness_code tmp;

      if (winner && TREE_PURPOSE (winner) == TREE_PURPOSE (conv))
	continue;

      if (tmp = convert_harshness (type, TREE_VALUE (conv), NULL_TREE),
	  (tmp.code < USER_CODE) && (tmp.distance >= 0))
	{
	  if (winner)
	    return EVIL_CODE;
	  else
	    {
	      winner = conv;
	      code = tmp.code;
	    }
	}
    }

  if (winner)
    return code;

  return -1;
}

int
can_convert (to, from)
     tree to, from;
{
  struct harshness_code h;
  h = convert_harshness (to, from, NULL_TREE);
  return (h.code < USER_CODE) && (h.distance >= 0);
}

int
can_convert_arg (to, from, arg)
     tree to, from, arg;
{
  struct harshness_code h;
  h = convert_harshness (to, from, arg);
  return (h.code < USER_CODE) && (h.distance >= 0);
}

#ifdef DEBUG_MATCHING
static char *
print_harshness (h)
     struct harshness_code *h;
{
  static char buf[1024];
  char tmp[1024];

  bzero (buf, 1024 * sizeof (char));
  strcat (buf, "codes=[");
  if (h->code & EVIL_CODE)
    strcat (buf, "EVIL");
  if (h->code & CONST_CODE)
    strcat (buf, " CONST");
  if (h->code & ELLIPSIS_CODE)
    strcat (buf, " ELLIPSIS");
  if (h->code & USER_CODE)
    strcat (buf, " USER");
  if (h->code & STD_CODE)
    strcat (buf, " STD");
  if (h->code & PROMO_CODE)
    strcat (buf, " PROMO");
  if (h->code & QUAL_CODE)
    strcat (buf, " QUAL");
  if (h->code & TRIVIAL_CODE)
    strcat (buf, " TRIVIAL");
  if (buf[0] == '\0')
    strcat (buf, "0");

  sprintf (tmp, "] distance=%d int_penalty=%d", h->distance, h->int_penalty);

  strcat (buf, tmp);

  return buf;
}
#endif

/* Algorithm: For each argument, calculate how difficult it is to
   make FUNCTION accept that argument.  If we can easily tell that
   FUNCTION won't be acceptable to one of the arguments, then we
   don't need to compute the ease of converting the other arguments,
   since it will never show up in the intersection of all arguments'
   favorite functions.

   Conversions between builtin and user-defined types are allowed, but
   no function involving such a conversion is preferred to one which
   does not require such a conversion.  Furthermore, such conversions
   must be unique.  */

void
compute_conversion_costs (function, tta_in, cp, arglen)
     tree function;
     tree tta_in;
     struct candidate *cp;
     int arglen;
{
  tree ttf_in = TYPE_ARG_TYPES (TREE_TYPE (function));
  tree ttf = ttf_in;
  tree tta = tta_in;

  /* Start out with no strikes against.  */
  int evil_strikes = 0;
  int ellipsis_strikes = 0;
  int user_strikes = 0;
  int b_or_d_strikes = 0;
  int easy_strikes = 0;

  int strike_index = 0, win;
  struct harshness_code lose;
  extern int cp_silent;

#ifdef GATHER_STATISTICS
  n_compute_conversion_costs++;
#endif

#ifndef DEBUG_MATCHING
  /* We don't emit any warnings or errors while trying out each candidate.  */
  cp_silent = 1;
#endif

  cp->function = function;
  cp->arg = tta ? TREE_VALUE (tta) : NULL_TREE;
  cp->u.bad_arg = 0;		/* optimistic!  */

  cp->h.code = 0;
  cp->h.distance = 0;
  cp->h.int_penalty = 0;
  bzero ((char *) cp->harshness,
	 (cp->h_len + 1) * sizeof (struct harshness_code));

  while (ttf && tta)
    {
      struct harshness_code h;

      if (ttf == void_list_node)
	break;

      if (type_unknown_p (TREE_VALUE (tta)))
	{	  
	  /* Must perform some instantiation here.  */
	  tree rhs = TREE_VALUE (tta);
	  tree lhstype = TREE_VALUE (ttf);

	  /* Keep quiet about possible contravariance violations.  */
	  int old_inhibit_warnings = inhibit_warnings;
	  inhibit_warnings = 1;

	  /* @@ This is to undo what `grokdeclarator' does to
	     parameter types.  It really should go through
	     something more general.  */

	  TREE_TYPE (tta) = unknown_type_node;
	  rhs = instantiate_type (lhstype, rhs, 0);
	  inhibit_warnings = old_inhibit_warnings;

	  if (TREE_CODE (rhs) == ERROR_MARK)
	    h.code = EVIL_CODE;
	  else
	    h = convert_harshness (lhstype, TREE_TYPE (rhs), rhs);
	}
      else
	{
#ifdef DEBUG_MATCHING
	  static tree old_function = NULL_TREE;

	  if (!old_function || function != old_function)
	    {
	      cp_error ("trying %D", function);
	      old_function = function;
	    }

	  cp_error ("      doing (%T) %E against arg %T",
		    TREE_TYPE (TREE_VALUE (tta)), TREE_VALUE (tta),
		    TREE_VALUE (ttf));
#endif

	  h = convert_harshness (TREE_VALUE (ttf),
				 TREE_TYPE (TREE_VALUE (tta)),
				 TREE_VALUE (tta));

#ifdef DEBUG_MATCHING
	  cp_error ("     evaluated %s", print_harshness (&h));
#endif
	}

      cp->harshness[strike_index] = h;
      if ((h.code & EVIL_CODE)
	  || ((h.code & STD_CODE) && h.distance < 0))
	{
	  cp->u.bad_arg = strike_index;
	  evil_strikes = 1;
	}
     else if (h.code & ELLIPSIS_CODE)
       ellipsis_strikes += 1;
#if 0
      /* This is never set by `convert_harshness'.  */
      else if (h.code & USER_CODE)
	{
	  user_strikes += 1;
	}
#endif
      else
	{
	  if ((h.code & STD_CODE) && h.distance)
	    {
	      if (h.distance > b_or_d_strikes)
		b_or_d_strikes = h.distance;
	    }
	  else
	    easy_strikes += (h.code & (STD_CODE|PROMO_CODE|TRIVIAL_CODE));
	  cp->h.code |= h.code;
	  /* Make sure we communicate this.  */
	  cp->h.int_penalty += h.int_penalty;
	}

      ttf = TREE_CHAIN (ttf);
      tta = TREE_CHAIN (tta);
      strike_index += 1;
    }

  if (tta)
    {
      /* ran out of formals, and parmlist is fixed size.  */
      if (ttf /* == void_type_node */)
	{
	  cp->h.code = EVIL_CODE;
	  cp->u.bad_arg = -1;
	  cp_silent = 0;
	  return;
	}
      else
	{
	  struct harshness_code h;
	  int l = list_length (tta);
	  ellipsis_strikes += l;
	  h.code = ELLIPSIS_CODE;
	  h.distance = 0;
	  h.int_penalty = 0;
	  for (; l; --l)
	    cp->harshness[strike_index++] = h;
	}
    }
  else if (ttf && ttf != void_list_node)
    {
      /* ran out of actuals, and no defaults.  */
      if (TREE_PURPOSE (ttf) == NULL_TREE)
	{
	  cp->h.code = EVIL_CODE;
	  cp->u.bad_arg = -2;
	  cp_silent = 0;
	  return;
	}
      /* Store index of first default.  */
      cp->harshness[arglen].distance = strike_index+1;
    }
  else
    cp->harshness[arglen].distance = 0;

  /* Argument list lengths work out, so don't need to check them again.  */
  if (evil_strikes)
    {
      /* We do not check for derived->base conversions here, since in
	 no case would they give evil strike counts, unless such conversions
	 are somehow ambiguous.  */

      /* See if any user-defined conversions apply.
         But make sure that we do not loop.  */
      static int dont_convert_types = 0;

      if (dont_convert_types)
	{
	  cp->h.code = EVIL_CODE;
	  cp_silent = 0;
	  return;
	}

      win = 0;			/* Only get one chance to win.  */
      ttf = TYPE_ARG_TYPES (TREE_TYPE (function));
      tta = tta_in;
      strike_index = 0;
      evil_strikes = 0;

      while (ttf && tta)
	{
	  if (ttf == void_list_node)
	    break;

	  lose = cp->harshness[strike_index];
	  if ((lose.code & EVIL_CODE)
	      || ((lose.code & STD_CODE) && lose.distance < 0))
	    {
	      tree actual_type = TREE_TYPE (TREE_VALUE (tta));
	      tree formal_type = TREE_VALUE (ttf);
	      int extra_conversions = 0;

	      dont_convert_types = 1;

	      if (TREE_CODE (formal_type) == REFERENCE_TYPE)
		formal_type = TREE_TYPE (formal_type);
	      if (TREE_CODE (actual_type) == REFERENCE_TYPE)
		actual_type = TREE_TYPE (actual_type);

	      if (formal_type != error_mark_node
		  && actual_type != error_mark_node)
		{
		  formal_type = TYPE_MAIN_VARIANT (formal_type);
		  actual_type = TYPE_MAIN_VARIANT (actual_type);

		  if (TYPE_HAS_CONSTRUCTOR (formal_type))
		    {
		      /* If it has a constructor for this type,
			 try to use it.  */
		      /* @@ There is no way to save this result yet, so
			 success is a NULL_TREE for now.  */
		      if (convert_to_aggr (formal_type, TREE_VALUE (tta), 0, 1)
			  != error_mark_node)
			win++;
		    }
		  if (TYPE_LANG_SPECIFIC (actual_type)
		      && TYPE_HAS_CONVERSION (actual_type))
		    {
		      int extra = user_harshness (formal_type, actual_type);

		      if (extra == EVIL_CODE)
			win += 2;
		      else if (extra >= 0)
			{
			  win++;
			  extra_conversions = extra;
			}
		    }
		}
	      dont_convert_types = 0;

	      if (win == 1)
		{
		  user_strikes += 1;
		  cp->harshness[strike_index].code
		    = USER_CODE | (extra_conversions ? STD_CODE : 0);
		  win = 0;
		}
	      else
		{
		  if (cp->u.bad_arg > strike_index)
		    cp->u.bad_arg = strike_index;

		  evil_strikes = win ? 2 : 1;
		  break;
		}
	    }

	  ttf = TREE_CHAIN (ttf);
	  tta = TREE_CHAIN (tta);
	  strike_index += 1;
	}
    }

  /* Const member functions get a small penalty because defaulting
     to const is less useful than defaulting to non-const. */
  /* This is bogus, it does not correspond to anything in the ARM.
     This code will be fixed when this entire section is rewritten
     to conform to the ARM.  (mrs)  */
  if (TREE_CODE (TREE_TYPE (function)) == METHOD_TYPE)
    {
      tree this_parm = TREE_VALUE (ttf_in);

      if (TREE_CODE (this_parm) == RECORD_TYPE	/* Is `this' a sig ptr?  */
	    ? TYPE_READONLY (TREE_TYPE (TREE_TYPE (TYPE_FIELDS (this_parm))))
	    : TYPE_READONLY (TREE_TYPE (this_parm)))
	{
	  cp->harshness[0].code |= TRIVIAL_CODE;
	  ++easy_strikes;
	}
      else
	{
	  /* Calling a non-const member function from a const member function
	     is probably invalid, but for now we let it only draw a warning.
	     We indicate that such a mismatch has occurred by setting the
	     harshness to a maximum value.  */
	  if (TREE_CODE (TREE_TYPE (TREE_VALUE (tta_in))) == POINTER_TYPE
	      && (TYPE_READONLY (TREE_TYPE (TREE_TYPE (TREE_VALUE (tta_in))))))
	    cp->harshness[0].code |= CONST_CODE;
	}
    }

  if (evil_strikes)
    cp->h.code = EVIL_CODE;
  if (ellipsis_strikes)
    cp->h.code |= ELLIPSIS_CODE;
  if (user_strikes)
    cp->h.code |= USER_CODE;
  cp_silent = 0;
#ifdef DEBUG_MATCHING
  cp_error ("final eval %s", print_harshness (&cp->h));
#endif
}

/* Subroutine of ideal_candidate.  See if X or Y is a better match
   than the other.  */
static int
strictly_better (x, y)
     unsigned short x, y;
{
  unsigned short xor;

  if (x == y)
    return 0;

  xor = x ^ y;
  if (xor >= x || xor >= y)
    return 1;
  return 0;
}

/* When one of several possible overloaded functions and/or methods
   can be called, choose the best candidate for overloading.

   BASETYPE is the context from which we start method resolution
   or NULL if we are comparing overloaded functions.
   CANDIDATES is the array of candidates we have to choose from.
   N_CANDIDATES is the length of CANDIDATES.
   PARMS is a TREE_LIST of parameters to the function we'll ultimately
   choose.  It is modified in place when resolving methods.  It is not
   modified in place when resolving overloaded functions.
   LEN is the length of the parameter list.  */

static struct candidate *
ideal_candidate (candidates, n_candidates, len)
     struct candidate *candidates;
     int n_candidates;
     int len;
{
  struct candidate *cp = candidates+n_candidates;
  int i, j = -1, best_code;

  /* For each argument, sort the functions from best to worst for the arg.
     For each function that's not best for this arg, set its overall
     harshness to EVIL so that other args won't like it.  The candidate
     list for the last argument is the intersection of all the best-liked
     functions.  */

  qsort (candidates, n_candidates, sizeof (struct candidate),
	 rank_for_overload);
  best_code = cp[-1].h.code;

  /* If they're at least as good as each other, do an arg-by-arg check.  */
  if (! strictly_better (cp[-1].h.code, cp[-2].h.code))
    {
      int better = 0;
      int worse = 0;

      for (j = 0; j < n_candidates; j++)
	if (! strictly_better (candidates[j].h.code, best_code))
	  break;

      qsort (candidates+j, n_candidates-j, sizeof (struct candidate),
	     rank_for_ideal);
      for (i = 0; i < len; i++)
	{
	  if (cp[-1].harshness[i].code < cp[-2].harshness[i].code)
	    better = 1;
	  else if (cp[-1].harshness[i].code > cp[-2].harshness[i].code)
	    worse = 1;
	  else if (cp[-1].harshness[i].code & STD_CODE)
	    {
	      /* If it involves a standard conversion, let the
		 inheritance lattice be the final arbiter.  */
	      if (cp[-1].harshness[i].distance > cp[-2].harshness[i].distance)
		worse = 1;
	      else if (cp[-1].harshness[i].distance < cp[-2].harshness[i].distance)
		better = 1;
	    }
	  else if (cp[-1].harshness[i].code & PROMO_CODE)
	    {
	      /* For integral promotions, take into account a finer
		 granularity for determining which types should be favored
		 over others in such promotions.  */
	      if (cp[-1].harshness[i].int_penalty > cp[-2].harshness[i].int_penalty)
		worse = 1;
	      else if (cp[-1].harshness[i].int_penalty < cp[-2].harshness[i].int_penalty)
		better = 1;
	    }
	}

      if (! better || worse)
	return NULL;
    }
  return cp-1;
}

/* Assume that if the class referred to is not in the
   current class hierarchy, that it may be remote.
   PARENT is assumed to be of aggregate type here.  */
static int
may_be_remote (parent)
     tree parent;
{
  if (TYPE_OVERLOADS_METHOD_CALL_EXPR (parent) == 0)
    return 0;

  if (current_class_type == NULL_TREE)
    return 0;

  if (parent == current_class_type)
    return 0;

  if (UNIQUELY_DERIVED_FROM_P (parent, current_class_type))
    return 0;
  return 1;
}

tree
build_vfield_ref (datum, type)
     tree datum, type;
{
  tree rval;
  int old_assume_nonnull_objects = flag_assume_nonnull_objects;

  if (datum == error_mark_node)
    return error_mark_node;

  /* Vtable references are always made from non-null objects.  */
  flag_assume_nonnull_objects = 1;
  if (TREE_CODE (TREE_TYPE (datum)) == REFERENCE_TYPE)
    datum = convert_from_reference (datum);

  if (! TYPE_USES_COMPLEX_INHERITANCE (type))
    rval = build (COMPONENT_REF, TREE_TYPE (CLASSTYPE_VFIELD (type)),
		  datum, CLASSTYPE_VFIELD (type));
  else
    rval = build_component_ref (datum, DECL_NAME (CLASSTYPE_VFIELD (type)), 0, 0);
  flag_assume_nonnull_objects = old_assume_nonnull_objects;

  return rval;
}

/* Build a call to a member of an object.  I.e., one that overloads
   operator ()(), or is a pointer-to-function or pointer-to-method.  */
static tree
build_field_call (basetype_path, instance_ptr, name, parms)
     tree basetype_path, instance_ptr, name, parms;
{
  tree field, instance;

  if (instance_ptr == current_class_decl)
    {
      /* Check to see if we really have a reference to an instance variable
	 with `operator()()' overloaded.  */
      field = IDENTIFIER_CLASS_VALUE (name);

      if (field == NULL_TREE)
	{
	  cp_error ("`this' has no member named `%D'", name);
	  return error_mark_node;
	}

      if (TREE_CODE (field) == FIELD_DECL)
	{
	  /* If it's a field, try overloading operator (),
	     or calling if the field is a pointer-to-function.  */
	  instance = build_component_ref_1 (C_C_D, field, 0);
	  if (instance == error_mark_node)
	    return error_mark_node;

	  if (TYPE_LANG_SPECIFIC (TREE_TYPE (instance))
	      && TYPE_OVERLOADS_CALL_EXPR (TREE_TYPE (instance)))
	    return build_opfncall (CALL_EXPR, LOOKUP_NORMAL, instance, parms, NULL_TREE);

	  if (TREE_CODE (TREE_TYPE (instance)) == POINTER_TYPE)
	    {
	      if (TREE_CODE (TREE_TYPE (TREE_TYPE (instance))) == FUNCTION_TYPE)
		return build_function_call (instance, parms);
	      else if (TREE_CODE (TREE_TYPE (TREE_TYPE (instance))) == METHOD_TYPE)
		return build_function_call (instance, tree_cons (NULL_TREE, current_class_decl, parms));
	    }
	}
      return NULL_TREE;
    }

  /* Check to see if this is not really a reference to an instance variable
     with `operator()()' overloaded.  */
  field = lookup_field (basetype_path, name, 1, 0);

  /* This can happen if the reference was ambiguous or for access
     violations.  */
  if (field == error_mark_node)
    return error_mark_node;

  if (field)
    {
      tree basetype;
      tree ftype = TREE_TYPE (field);

      if (TREE_CODE (ftype) == REFERENCE_TYPE)
	ftype = TREE_TYPE (ftype);

      if (TYPE_LANG_SPECIFIC (ftype) && TYPE_OVERLOADS_CALL_EXPR (ftype))
	{
	  /* Make the next search for this field very short.  */
	  basetype = DECL_FIELD_CONTEXT (field);
	  instance_ptr = convert_pointer_to (basetype, instance_ptr);

	  instance = build_indirect_ref (instance_ptr, NULL_PTR);
	  return build_opfncall (CALL_EXPR, LOOKUP_NORMAL,
				 build_component_ref_1 (instance, field, 0),
				 parms, NULL_TREE);
	}
      if (TREE_CODE (ftype) == POINTER_TYPE)
	{
	  if (TREE_CODE (TREE_TYPE (ftype)) == FUNCTION_TYPE
	      || TREE_CODE (TREE_TYPE (ftype)) == METHOD_TYPE)
	    {
	      /* This is a member which is a pointer to function.  */
	      tree ref
		= build_component_ref_1 (build_indirect_ref (instance_ptr,
							     NULL_PTR),
					 field, LOOKUP_COMPLAIN);
	      if (ref == error_mark_node)
		return error_mark_node;
	      return build_function_call (ref, parms);
	    }
	}
      else if (TREE_CODE (ftype) == METHOD_TYPE)
	{
	  error ("invalid call via pointer-to-member function");
	  return error_mark_node;
	}
      else
	return NULL_TREE;
    }
  return NULL_TREE;
}

tree
find_scoped_type (type, inner_name, inner_types)
     tree type, inner_name, inner_types;
{
  tree tags = CLASSTYPE_TAGS (type);

  while (tags)
    {
      /* The TREE_PURPOSE of an enum tag (which becomes a member of the
	 enclosing class) is set to the name for the enum type.  So, if
	 inner_name is `bar', and we strike `baz' for `enum bar { baz }',
	 then this test will be true.  */
      if (TREE_PURPOSE (tags) == inner_name)
	{
	  if (inner_types == NULL_TREE)
	    return TYPE_NAME (TREE_VALUE (tags));
	  return resolve_scope_to_name (TREE_VALUE (tags), inner_types);
	}
      tags = TREE_CHAIN (tags);
    }

  /* Look for a TYPE_DECL.  */
  for (tags = TYPE_FIELDS (type); tags; tags = TREE_CHAIN (tags))
    if (TREE_CODE (tags) == TYPE_DECL && DECL_NAME (tags) == inner_name)
      {
	/* Code by raeburn.  */
	if (inner_types == NULL_TREE)
	  return tags;
	return resolve_scope_to_name (TREE_TYPE (tags), inner_types);
      }

  return NULL_TREE;
}

/* Resolve an expression NAME1::NAME2::...::NAMEn to
   the name that names the above nested type.  INNER_TYPES
   is a chain of nested type names (held together by SCOPE_REFs);
   OUTER_TYPE is the type we know to enclose INNER_TYPES.
   Returns NULL_TREE if there is an error.  */
tree
resolve_scope_to_name (outer_type, inner_stuff)
     tree outer_type, inner_stuff;
{
  register tree tmp;
  tree inner_name, inner_type;

  if (outer_type == NULL_TREE && current_class_type != NULL_TREE)
    {
      /* We first try to look for a nesting in our current class context,
         then try any enclosing classes.  */
      tree type = current_class_type;
      
      while (type && (TREE_CODE (type) == RECORD_TYPE
		      || TREE_CODE (type) == UNION_TYPE))
        {
          tree rval = resolve_scope_to_name (type, inner_stuff);

	  if (rval != NULL_TREE)
	    return rval;
	  type = DECL_CONTEXT (TYPE_NAME (type));
	}
    }

  if (TREE_CODE (inner_stuff) == SCOPE_REF)
    {
      inner_name = TREE_OPERAND (inner_stuff, 0);
      inner_type = TREE_OPERAND (inner_stuff, 1);
    }
  else
    {
      inner_name = inner_stuff;
      inner_type = NULL_TREE;
    }

  if (outer_type == NULL_TREE)
    {
      tree x;
      /* If we have something that's already a type by itself,
	 use that.  */
      if (IDENTIFIER_HAS_TYPE_VALUE (inner_name))
	{
	  if (inner_type)
	    return resolve_scope_to_name (IDENTIFIER_TYPE_VALUE (inner_name),
					  inner_type);
	  return inner_name;
	}
      
      x = lookup_name (inner_name, 0);

      if (x && TREE_CODE (x) == NAMESPACE_DECL)
	{
	  x = lookup_namespace_name (x, inner_type);
	  return x;
	}
      return NULL_TREE;
    }

  if (! IS_AGGR_TYPE (outer_type))
    return NULL_TREE;

  /* Look for member classes or enums.  */
  tmp = find_scoped_type (outer_type, inner_name, inner_type);

  /* If it's not a type in this class, then go down into the
     base classes and search there.  */
  if (! tmp && TYPE_BINFO (outer_type))
    {
      tree binfos = TYPE_BINFO_BASETYPES (outer_type);
      int i, n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0;

      for (i = 0; i < n_baselinks; i++)
	{
	  tree base_binfo = TREE_VEC_ELT (binfos, i);
	  tmp = resolve_scope_to_name (BINFO_TYPE (base_binfo), inner_stuff);
	  if (tmp)
	    return tmp;
	}
      tmp = NULL_TREE;
    }

  return tmp;
}

/* Build a method call of the form `EXP->SCOPES::NAME (PARMS)'.
   This is how virtual function calls are avoided.  */
tree
build_scoped_method_call (exp, basetype, name, parms)
     tree exp, basetype, name, parms;
{
  /* Because this syntactic form does not allow
     a pointer to a base class to be `stolen',
     we need not protect the derived->base conversion
     that happens here.
     
     @@ But we do have to check access privileges later.  */
  tree binfo, decl;
  tree type = TREE_TYPE (exp);

  if (type == error_mark_node
      || basetype == error_mark_node)
    return error_mark_node;

  if (current_template_parms)
    {
      if (TREE_CODE (name) == BIT_NOT_EXPR)
	{
	  tree type = get_aggr_from_typedef (TREE_OPERAND (name, 0), 1);
	  name = build_min_nt (BIT_NOT_EXPR, type);
	}
      name = build_min_nt (SCOPE_REF, basetype, name);
      return build_min_nt (METHOD_CALL_EXPR, name, exp, parms, 0);
    }

  if (TREE_CODE (type) == REFERENCE_TYPE)
    type = TREE_TYPE (type);

  /* Destructors can be "called" for simple types; see 5.2.4 and 12.4 Note
     that explicit ~int is caught in the parser; this deals with typedefs
     and template parms.  */
  if (TREE_CODE (name) == BIT_NOT_EXPR && ! IS_AGGR_TYPE (basetype))
    {
      if (type != basetype)
	cp_error ("type of `%E' does not match destructor type `%T' (type was `%T')",
		  exp, basetype, type);
      name = TREE_OPERAND (name, 0);
      if (basetype != name && basetype != get_type_value (name))
	cp_error ("qualified type `%T' does not match destructor name `~%T'",
		  basetype, name);
      return convert (void_type_node, exp);
    }

  if (! is_aggr_type (basetype, 1))
    return error_mark_node;

  if (! IS_AGGR_TYPE (type))
    {
      cp_error ("base object `%E' of scoped method call is of non-aggregate type `%T'",
		exp, type);
      return error_mark_node;
    }

  if ((binfo = binfo_or_else (basetype, type)))
    {
      if (binfo == error_mark_node)
	return error_mark_node;
      if (TREE_CODE (exp) == INDIRECT_REF)
	decl = build_indirect_ref (convert_pointer_to (binfo,
						       build_unary_op (ADDR_EXPR, exp, 0)), NULL_PTR);
      else
	decl = build_scoped_ref (exp, basetype);

      /* Call to a destructor.  */
      if (TREE_CODE (name) == BIT_NOT_EXPR)
	{
	  /* Explicit call to destructor.  */
	  name = TREE_OPERAND (name, 0);
	  if (! (name == TYPE_MAIN_VARIANT (TREE_TYPE (decl))
		 || name == constructor_name (TREE_TYPE (decl))
		 || TREE_TYPE (decl) == get_type_value (name)))
	    {
	      cp_error
		("qualified type `%T' does not match destructor name `~%T'",
		 TREE_TYPE (decl), name);
	      return error_mark_node;
	    }
	  if (! TYPE_HAS_DESTRUCTOR (TREE_TYPE (decl)))
	    return convert (void_type_node, exp);
	  
	  return build_delete (TREE_TYPE (decl), decl, integer_two_node,
			       LOOKUP_NORMAL|LOOKUP_NONVIRTUAL|LOOKUP_DESTRUCTOR,
			       0);
	}

      /* Call to a method.  */
      return build_method_call (decl, name, parms, binfo,
				LOOKUP_NORMAL|LOOKUP_NONVIRTUAL);
    }
  return error_mark_node;
}

static void
print_candidates (candidates)
     tree candidates;
{
  cp_error_at ("candidates are: %D", TREE_VALUE (candidates));
  candidates = TREE_CHAIN (candidates);

  while (candidates)
    {
      cp_error_at ("                %D", TREE_VALUE (candidates));
      candidates = TREE_CHAIN (candidates);
    }
}

static void
print_n_candidates (candidates, n)
     struct candidate *candidates;
     int n;
{
  int i;

  cp_error_at ("candidates are: %D", candidates[0].function);
  for (i = 1; i < n; i++)
    cp_error_at ("                %D", candidates[i].function);
}

/* Build something of the form ptr->method (args)
   or object.method (args).  This can also build
   calls to constructors, and find friends.

   Member functions always take their class variable
   as a pointer.

   INSTANCE is a class instance.

   NAME is the name of the method desired, usually an IDENTIFIER_NODE.

   PARMS help to figure out what that NAME really refers to.

   BASETYPE_PATH, if non-NULL, contains a chain from the type of INSTANCE
   down to the real instance type to use for access checking.  We need this
   information to get protected accesses correct.  This parameter is used
   by build_member_call.

   FLAGS is the logical disjunction of zero or more LOOKUP_
   flags.  See cp-tree.h for more info.

   If this is all OK, calls build_function_call with the resolved
   member function.

   This function must also handle being called to perform
   initialization, promotion/coercion of arguments, and
   instantiation of default parameters.

   Note that NAME may refer to an instance variable name.  If
   `operator()()' is defined for the type of that field, then we return
   that result.  */
tree
build_method_call (instance, name, parms, basetype_path, flags)
     tree instance, name, parms, basetype_path;
     int flags;
{
  register tree function, fntype, value_type;
  register tree basetype, save_basetype;
  register tree baselink, result, parmtypes, parm;
  tree last;
  int pass;
  tree access = access_public_node;
  tree orig_basetype = basetype_path ? BINFO_TYPE (basetype_path) : NULL_TREE;

  /* Range of cases for vtable optimization.  */
  enum vtable_needs { not_needed, maybe_needed, unneeded, needed };
  enum vtable_needs need_vtbl = not_needed;

  char *name_kind;
  tree save_name = name;
  int ever_seen = 0;
  tree instance_ptr = NULL_TREE;
  int all_virtual = flag_all_virtual;
  int static_call_context = 0;
  tree found_fns = NULL_TREE;

  /* Keep track of `const' and `volatile' objects.  */
  int constp, volatilep;

#ifdef GATHER_STATISTICS
  n_build_method_call++;
#endif

  if (instance == error_mark_node
      || name == error_mark_node
      || parms == error_mark_node
      || (instance != NULL_TREE && TREE_TYPE (instance) == error_mark_node))
    return error_mark_node;

  if (current_template_parms)
    {
      if (TREE_CODE (name) == BIT_NOT_EXPR)
	{
	  tree type = get_aggr_from_typedef (TREE_OPERAND (name, 0), 1);
	  name = build_min_nt (BIT_NOT_EXPR, type);
	}

      return build_min_nt (METHOD_CALL_EXPR, name, instance, parms, 0);
    }

  /* This is the logic that magically deletes the second argument to
     operator delete, if it is not needed. */
  if (name == ansi_opname[(int) DELETE_EXPR] && list_length (parms)==2)
    {
      tree save_last = TREE_CHAIN (parms);
      tree result;
      /* get rid of unneeded argument */
      TREE_CHAIN (parms) = NULL_TREE;
      result = build_method_call (instance, name, parms, basetype_path,
				  (LOOKUP_SPECULATIVELY|flags)
				  &~LOOKUP_COMPLAIN);
      /* If it finds a match, return it. */
      if (result)
	return build_method_call (instance, name, parms, basetype_path, flags);
      /* If it doesn't work, two argument delete must work */
      TREE_CHAIN (parms) = save_last;
    }
  /* We already know whether it's needed or not for vec delete.  */
  else if (name == ansi_opname[(int) VEC_DELETE_EXPR]
	   && TYPE_LANG_SPECIFIC (TREE_TYPE (instance))
	   && ! TYPE_VEC_DELETE_TAKES_SIZE (TREE_TYPE (instance)))
    TREE_CHAIN (parms) = NULL_TREE;

  if (TREE_CODE (name) == BIT_NOT_EXPR)
    {
      flags |= LOOKUP_DESTRUCTOR;
      name = TREE_OPERAND (name, 0);
      if (parms)
	error ("destructors take no parameters");
      basetype = TREE_TYPE (instance);
      if (TREE_CODE (basetype) == REFERENCE_TYPE)
	basetype = TREE_TYPE (basetype);
      if (! (name == basetype
	     || (IS_AGGR_TYPE (basetype)
		 && name == constructor_name (basetype))
	     || basetype == get_type_value (name)))
	{
	  cp_error ("destructor name `~%D' does not match type `%T' of expression",
		    name, basetype);
	  return convert (void_type_node, instance);
	}

      if (! TYPE_HAS_DESTRUCTOR (basetype))
	return convert (void_type_node, instance);
      instance = default_conversion (instance);
      instance_ptr = build_unary_op (ADDR_EXPR, instance, 0);
      return build_delete (build_pointer_type (basetype),
			   instance_ptr, integer_two_node,
			   LOOKUP_NORMAL|LOOKUP_DESTRUCTOR, 0);
    }

  {
    char *xref_name;
    
    /* Initialize name for error reporting.  */
    if (IDENTIFIER_OPNAME_P (name) && ! IDENTIFIER_TYPENAME_P (name))
      {
	char *p = operator_name_string (name);
	xref_name = (char *)alloca (strlen (p) + 10);
	sprintf (xref_name, "operator %s", p);
      }
    else if (TREE_CODE (name) == SCOPE_REF)
      xref_name = IDENTIFIER_POINTER (TREE_OPERAND (name, 1));
    else
      xref_name = IDENTIFIER_POINTER (name);

    GNU_xref_call (current_function_decl, xref_name);
  }

  if (instance == NULL_TREE)
    {
      basetype = NULL_TREE;
      /* Check cases where this is really a call to raise
	 an exception.  */
      if (current_class_type && TREE_CODE (name) == IDENTIFIER_NODE)
	{
	  basetype = purpose_member (name, CLASSTYPE_TAGS (current_class_type));
	  if (basetype)
	    basetype = TREE_VALUE (basetype);
	}
      else if (TREE_CODE (name) == SCOPE_REF
	       && TREE_CODE (TREE_OPERAND (name, 0)) == IDENTIFIER_NODE)
	{
	  if (! is_aggr_typedef (TREE_OPERAND (name, 0), 1))
	    return error_mark_node;
	  basetype = purpose_member (TREE_OPERAND (name, 1),
				     CLASSTYPE_TAGS (IDENTIFIER_TYPE_VALUE (TREE_OPERAND (name, 0))));
	  if (basetype)
	    basetype = TREE_VALUE (basetype);
	}

      if (basetype != NULL_TREE)
	;
      /* call to a constructor... */
      else if (basetype_path)
	{
	  basetype = BINFO_TYPE (basetype_path);
	  if (name == TYPE_IDENTIFIER (basetype))
	    name = ctor_identifier;
	}
      else if (IDENTIFIER_HAS_TYPE_VALUE (name))
	{
	  basetype = IDENTIFIER_TYPE_VALUE (name);
	  name = ctor_identifier;
	}
      else
	{
	  tree typedef_name = lookup_name (name, 1);
	  if (typedef_name && TREE_CODE (typedef_name) == TYPE_DECL)
	    {
	      /* Canonicalize the typedef name.  */
	      basetype = TREE_TYPE (typedef_name);
	      name = ctor_identifier;
	    }
	  else
	    {
	      cp_error ("no constructor named `%T' in scope",
			name);
	      return error_mark_node;
	    }
	}

      if (! IS_AGGR_TYPE (basetype))
	{
	non_aggr_error:
	  if ((flags & LOOKUP_COMPLAIN) && TREE_CODE (basetype) != ERROR_MARK)
	    cp_error ("request for member `%D' in `%E', which is of non-aggregate type `%T'",
		      name, instance, basetype);

	  return error_mark_node;
	}
    }
  else if (instance == C_C_D || instance == current_class_decl)
    {
      /* When doing initialization, we side-effect the TREE_TYPE of
	 C_C_D, hence we cannot set up BASETYPE from CURRENT_CLASS_TYPE.  */
      basetype = TREE_TYPE (C_C_D);

      /* Anything manifestly `this' in constructors and destructors
	 has a known type, so virtual function tables are not needed.  */
      if (TYPE_VIRTUAL_P (basetype)
	  && !(flags & LOOKUP_NONVIRTUAL))
	need_vtbl = (dtor_label || ctor_label)
	  ? unneeded : maybe_needed;

      /* If `this' is a signature pointer and `name' is not a constructor,
	 we are calling a signature member function.  In that case, set the
	 `basetype' to the signature type and dereference the `optr' field.  */
      if (IS_SIGNATURE_POINTER (basetype)
	  && TYPE_IDENTIFIER (basetype) != name)
	{
	  basetype = SIGNATURE_TYPE (basetype);
	  instance_ptr = build_optr_ref (instance);
	  instance_ptr = convert (build_pointer_type (basetype), instance_ptr);
	  basetype_path = TYPE_BINFO (basetype);
	}
      else
	{
	  instance = C_C_D;
	  instance_ptr = current_class_decl;
	  basetype_path = TYPE_BINFO (current_class_type);
	}
      result = build_field_call (basetype_path, instance_ptr, name, parms);

      if (result)
	return result;
    }
  else if (TREE_CODE (instance) == RESULT_DECL)
    {
      basetype = TREE_TYPE (instance);
      /* Should we ever have to make a virtual function reference
	 from a RESULT_DECL, know that it must be of fixed type
	 within the scope of this function.  */
      if (!(flags & LOOKUP_NONVIRTUAL) && TYPE_VIRTUAL_P (basetype))
	need_vtbl = maybe_needed;
      instance_ptr = build1 (ADDR_EXPR, build_pointer_type (basetype), instance);
    }
  else
    {
      /* The MAIN_VARIANT of the type that `instance_ptr' winds up being.  */
      tree inst_ptr_basetype;

      static_call_context =
	(TREE_CODE (instance) == INDIRECT_REF
	 && TREE_CODE (TREE_OPERAND (instance, 0)) == NOP_EXPR
	 && TREE_OPERAND (TREE_OPERAND (instance, 0), 0) == error_mark_node);

      if (TREE_CODE (instance) == OFFSET_REF)
	instance = resolve_offset_ref (instance);

      /* the base type of an instance variable is pointer to class */
      basetype = TREE_TYPE (instance);

      if (TREE_CODE (basetype) == REFERENCE_TYPE)
	{
	  basetype = TREE_TYPE (basetype);
	  if (! IS_AGGR_TYPE (basetype))
	    goto non_aggr_error;
	  /* Call to convert not needed because we are remaining
	     within the same type.  */
	  instance_ptr = build1 (NOP_EXPR, build_pointer_type (basetype),
				 instance);
	  inst_ptr_basetype = TYPE_MAIN_VARIANT (basetype);
	}
      else
	{
	  if (! IS_AGGR_TYPE (basetype)
	      && ! (TYPE_LANG_SPECIFIC (basetype)
		    && (IS_SIGNATURE_POINTER (basetype)
			|| IS_SIGNATURE_REFERENCE (basetype))))
	    goto non_aggr_error;

	  /* If `instance' is a signature pointer/reference and `name' is
	     not a constructor, we are calling a signature member function.
	     In that case set the `basetype' to the signature type.  */
	  if ((IS_SIGNATURE_POINTER (basetype)
	       || IS_SIGNATURE_REFERENCE (basetype))
	      && TYPE_IDENTIFIER (basetype) != name)
	    basetype = SIGNATURE_TYPE (basetype);

	  if ((IS_SIGNATURE (basetype)
	       && (instance_ptr = instance))
	      || (lvalue_p (instance)
		  && (instance_ptr = build_unary_op (ADDR_EXPR, instance, 0)))
	      || (instance_ptr = unary_complex_lvalue (ADDR_EXPR, instance)))
	    {
	      if (instance_ptr == error_mark_node)
		return error_mark_node;
	    }
	  else if (TREE_CODE (instance) == NOP_EXPR
		   || TREE_CODE (instance) == CONSTRUCTOR)
	    {
	      /* A cast is not an lvalue.  Initialize a fresh temp
		 with the value we are casting from, and proceed with
		 that temporary.  We can't cast to a reference type,
		 so that simplifies the initialization to something
		 we can manage.  */
	      tree temp = get_temp_name (TREE_TYPE (instance), 0);
	      if (IS_AGGR_TYPE (TREE_TYPE (instance)))
		expand_aggr_init (temp, instance, 0, flags);
	      else
		{
		  store_init_value (temp, instance);
		  expand_decl_init (temp);
		}
	      instance = temp;
	      instance_ptr = build_unary_op (ADDR_EXPR, instance, 0);
	    }
	  else
	    {
	      if (TREE_CODE (instance) != CALL_EXPR)
		my_friendly_abort (125);
	      if (TYPE_NEEDS_CONSTRUCTING (basetype))
		instance = build_cplus_new (basetype, instance);
	      else
		{
		  instance = get_temp_name (basetype, 0);
		  TREE_ADDRESSABLE (instance) = 1;
		}
	      instance_ptr = build_unary_op (ADDR_EXPR, instance, 0);
	    }
	  /* @@ Should we call comp_target_types here?  */
	  if (IS_SIGNATURE (basetype))
	    inst_ptr_basetype = basetype;
	  else
	    inst_ptr_basetype = TREE_TYPE (TREE_TYPE (instance_ptr));
	  if (TYPE_MAIN_VARIANT (basetype) == TYPE_MAIN_VARIANT (inst_ptr_basetype))
	    basetype = inst_ptr_basetype;
	  else
	    {
	      instance_ptr = convert (build_pointer_type (basetype), instance_ptr);
	      if (instance_ptr == error_mark_node)
		return error_mark_node;
	    }
	}

      /* After converting `instance_ptr' above, `inst_ptr_basetype' was
	 not updated, so we use `basetype' instead.  */
      if (basetype_path == NULL_TREE
	  && IS_SIGNATURE (basetype))
	basetype_path = TYPE_BINFO (basetype);
      else if (basetype_path == NULL_TREE ||
	BINFO_TYPE (basetype_path) != TYPE_MAIN_VARIANT (inst_ptr_basetype))
	basetype_path = TYPE_BINFO (inst_ptr_basetype);

      result = build_field_call (basetype_path, instance_ptr, name, parms);
      if (result)
	return result;

      if (!(flags & LOOKUP_NONVIRTUAL) && TYPE_VIRTUAL_P (basetype))
	{
	  if (TREE_SIDE_EFFECTS (instance_ptr))
	    {
	      /* This action is needed because the instance is needed
		 for providing the base of the virtual function table.
		 Without using a SAVE_EXPR, the function we are building
		 may be called twice, or side effects on the instance
		 variable (such as a post-increment), may happen twice.  */
	      instance_ptr = save_expr (instance_ptr);
	      instance = build_indirect_ref (instance_ptr, NULL_PTR);
	    }
	  else if (TREE_CODE (TREE_TYPE (instance)) == POINTER_TYPE)
	    {
	      /* This happens when called for operator new ().  */
	      instance = build_indirect_ref (instance, NULL_PTR);
	    }

	  need_vtbl = maybe_needed;
	}
    }

  if (save_name == ctor_identifier)
    save_name = TYPE_IDENTIFIER (basetype);

  if (TYPE_SIZE (complete_type (basetype)) == 0)
    {
      /* This is worth complaining about, I think.  */
      cp_error ("cannot lookup method in incomplete type `%T'", basetype);
      return error_mark_node;
    }

  save_basetype = TYPE_MAIN_VARIANT (basetype);

  last = NULL_TREE;
  for (parmtypes = NULL_TREE, parm = parms; parm; parm = TREE_CHAIN (parm))
    {
      tree t = TREE_TYPE (TREE_VALUE (parm));
      if (TREE_CODE (t) == OFFSET_TYPE)
	{
	  /* Convert OFFSET_TYPE entities to their normal selves.  */
	  TREE_VALUE (parm) = resolve_offset_ref (TREE_VALUE (parm));
	  t = TREE_TYPE (TREE_VALUE (parm));
	}
      if (TREE_CODE (TREE_VALUE (parm)) == OFFSET_REF
	  && TREE_CODE (t) == METHOD_TYPE)
	{
	  TREE_VALUE (parm) = build_unary_op (ADDR_EXPR, TREE_VALUE (parm), 0);
	}
#if 0
      /* This breaks reference-to-array parameters.  */
      if (TREE_CODE (t) == ARRAY_TYPE)
	{
	  /* Perform the conversion from ARRAY_TYPE to POINTER_TYPE in place.
	     This eliminates needless calls to `compute_conversion_costs'.  */
	  TREE_VALUE (parm) = default_conversion (TREE_VALUE (parm));
	  t = TREE_TYPE (TREE_VALUE (parm));
	}
#endif
      if (t == error_mark_node)
	return error_mark_node;
      last = build_tree_list (NULL_TREE, t);
      parmtypes = chainon (parmtypes, last);
    }

  if (instance && IS_SIGNATURE (basetype))
    {
      /* @@ Should this be the constp/volatilep flags for the optr field
	 of the signature pointer?  */
      constp = TYPE_READONLY (basetype);
      volatilep = TYPE_VOLATILE (basetype);
      parms = tree_cons (NULL_TREE, instance_ptr, parms);
    }
  else if (instance)
    {
      /* TREE_READONLY (instance) fails for references.  */
      constp = TYPE_READONLY (TREE_TYPE (TREE_TYPE (instance_ptr)));
      volatilep = TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (instance_ptr)));
      parms = tree_cons (NULL_TREE, instance_ptr, parms);
    }
  else
    {
      /* Raw constructors are always in charge.  */
      if (TYPE_USES_VIRTUAL_BASECLASSES (basetype)
	  && ! (flags & LOOKUP_HAS_IN_CHARGE))
	{
	  flags |= LOOKUP_HAS_IN_CHARGE;
	  parms = tree_cons (NULL_TREE, integer_one_node, parms);
	  parmtypes = tree_cons (NULL_TREE, integer_type_node, parmtypes);
	}

      constp = 0;
      volatilep = 0;
      instance_ptr = build_int_2 (0, 0);
      TREE_TYPE (instance_ptr) = build_pointer_type (basetype);
      parms = tree_cons (NULL_TREE, instance_ptr, parms);
    }

  parmtypes = tree_cons (NULL_TREE, TREE_TYPE (instance_ptr), parmtypes);

  if (last == NULL_TREE)
    last = parmtypes;

  /* Look up function name in the structure type definition.  */

  /* FIXME Axe most of this now?  */
  if ((IDENTIFIER_HAS_TYPE_VALUE (name)
       && ! IDENTIFIER_OPNAME_P (name)
       && IS_AGGR_TYPE (IDENTIFIER_TYPE_VALUE (name)))
      || name == constructor_name (basetype)
      || name == ctor_identifier)
    {
      tree tmp = NULL_TREE;
      if (IDENTIFIER_TYPE_VALUE (name) == basetype
	  || name == constructor_name (basetype)
	  || name == ctor_identifier)
	tmp = TYPE_BINFO (basetype);
      else
	tmp = get_binfo (IDENTIFIER_TYPE_VALUE (name), basetype, 0);
      
      if (tmp != NULL_TREE)
	{
	  name_kind = "constructor";
	  
	  if (TYPE_USES_VIRTUAL_BASECLASSES (basetype)
	      && ! (flags & LOOKUP_HAS_IN_CHARGE))
	    {
	      /* Constructors called for initialization
		 only are never in charge.  */
	      tree tmplist;
	      
	      flags |= LOOKUP_HAS_IN_CHARGE;
	      tmplist = tree_cons (NULL_TREE, integer_zero_node,
				   TREE_CHAIN (parms));
	      TREE_CHAIN (parms) = tmplist;
	      tmplist = tree_cons (NULL_TREE, integer_type_node, TREE_CHAIN (parmtypes));
	      TREE_CHAIN (parmtypes) = tmplist;
	    }
	  basetype = BINFO_TYPE (tmp);
	}
      else
	name_kind = "method";
    }
  else
    name_kind = "method";
  
  if (basetype_path == NULL_TREE
      || BINFO_TYPE (basetype_path) != TYPE_MAIN_VARIANT (basetype))
    basetype_path = TYPE_BINFO (basetype);
  result = lookup_fnfields (basetype_path, name,
			    (flags & LOOKUP_COMPLAIN));
  if (result == error_mark_node)
    return error_mark_node;

  for (pass = 0; pass < 2; pass++)
    {
      struct candidate *candidates;
      struct candidate *cp;
      int len;
      unsigned best = 1;

      baselink = result;

      if (pass > 0)
	{
	  candidates
	    = (struct candidate *) alloca ((ever_seen+1)
					   * sizeof (struct candidate));
	  bzero ((char *) candidates, (ever_seen + 1) * sizeof (struct candidate));
	  cp = candidates;
	  len = list_length (parms);
	  ever_seen = 0;

	  /* First see if a global function has a shot at it.  */
	  if (flags & LOOKUP_GLOBAL)
	    {
	      tree friend_parms;
	      tree parm = instance_ptr;

	      if (TREE_CODE (TREE_TYPE (parm)) == REFERENCE_TYPE)
		parm = convert_from_reference (parm);
	      else if (TREE_CODE (TREE_TYPE (parm)) == POINTER_TYPE)
		parm = build_indirect_ref (parm, "friendifying parms (compiler error)");
	      else
		my_friendly_abort (167);

	      friend_parms = tree_cons (NULL_TREE, parm, TREE_CHAIN (parms));

	      cp->h_len = len;
	      cp->harshness = (struct harshness_code *)
		alloca ((len + 1) * sizeof (struct harshness_code));

	      result = build_overload_call (name, friend_parms, 0, cp);
	      /* If it turns out to be the one we were actually looking for
		 (it was probably a friend function), the return the
		 good result.  */
	      if (TREE_CODE (result) == CALL_EXPR)
		return result;

	      while ((cp->h.code & EVIL_CODE) == 0)
		{
		  /* non-standard uses: set the field to 0 to indicate
		     we are using a non-member function.  */
		  cp->u.field = 0;
		  if (cp->harshness[len].distance == 0
		      && cp->h.code < best)
		    best = cp->h.code;
		  cp += 1;
		}
	    }
	}

      if (baselink)
	{
	  /* We have a hit (of sorts). If the parameter list is
	     "error_mark_node", or some variant thereof, it won't
	     match any methods.  Since we have verified that the is
	     some method vaguely matching this one (in name at least),
	     silently return.
	     
	     Don't stop for friends, however.  */
	  basetype_path = TREE_PURPOSE (baselink);

	  function = TREE_VALUE (baselink);
	  if (TREE_CODE (basetype_path) == TREE_LIST)
	    basetype_path = TREE_VALUE (basetype_path);
	  basetype = BINFO_TYPE (basetype_path);

	  for (; function; function = DECL_CHAIN (function))
	    {
#ifdef GATHER_STATISTICS
	      n_inner_fields_searched++;
#endif
	      ever_seen++;
	      if (pass > 0)
		found_fns = tree_cons (NULL_TREE, function, found_fns);

	      /* Not looking for friends here.  */
	      if (TREE_CODE (TREE_TYPE (function)) == FUNCTION_TYPE
		  && ! DECL_STATIC_FUNCTION_P (function))
		continue;

	      if (pass > 0)
		{
		  tree these_parms = parms;

#ifdef GATHER_STATISTICS
		  n_inner_fields_searched++;
#endif
		  cp->h_len = len;
		  cp->harshness = (struct harshness_code *)
		    alloca ((len + 1) * sizeof (struct harshness_code));

		  if (DECL_STATIC_FUNCTION_P (function))
		    these_parms = TREE_CHAIN (these_parms);
		  compute_conversion_costs (function, these_parms, cp, len);

		  if ((cp->h.code & EVIL_CODE) == 0)
		    {
		      cp->u.field = function;
		      cp->function = function;
		      cp->basetypes = basetype_path;

		      /* Don't allow non-converting constructors to convert. */
		      if (flags & LOOKUP_ONLYCONVERTING
			  && DECL_LANG_SPECIFIC (function)
			  && DECL_NONCONVERTING_P (function))
			continue;

		      /* No "two-level" conversions.  */
		      if (flags & LOOKUP_NO_CONVERSION
			  && (cp->h.code & USER_CODE))
			continue;

		      cp++;
		    }
		}
	    }
	}

      if (pass == 0)
	{
	  tree igv = lookup_name_nonclass (name);

	  /* No exact match could be found.  Now try to find match
	     using default conversions.  */
	  if ((flags & LOOKUP_GLOBAL) && igv)
	    {
	      if (TREE_CODE (igv) == FUNCTION_DECL)
		ever_seen += 1;
	      else if (TREE_CODE (igv) == TREE_LIST)
		ever_seen += count_functions (igv);
	    }

	  if (ever_seen == 0)
	    {
	      if ((flags & (LOOKUP_SPECULATIVELY|LOOKUP_COMPLAIN))
		  == LOOKUP_SPECULATIVELY)
		return NULL_TREE;
	      
	      TREE_CHAIN (last) = void_list_node;
	      if (flags & LOOKUP_GLOBAL)
		cp_error ("no global or member function `%D(%A)' defined",
			  save_name, parmtypes);
	      else
		cp_error ("no member function `%T::%D(%A)' defined",
			  save_basetype, save_name, TREE_CHAIN (parmtypes));
	      return error_mark_node;
	    }
	  continue;
	}

      if (cp - candidates != 0)
	{
	  /* Rank from worst to best.  Then cp will point to best one.
	     Private fields have their bits flipped.  For unsigned
	     numbers, this should make them look very large.
	     If the best alternate has a (signed) negative value,
	     then all we ever saw were private members.  */
	  if (cp - candidates > 1)
	    {
	      int n_candidates = cp - candidates;
	      extern int warn_synth;
	      TREE_VALUE (parms) = instance_ptr;
	      cp = ideal_candidate (candidates, n_candidates, len);
	      if (cp == (struct candidate *)0)
		{
		  if (flags & LOOKUP_COMPLAIN)
		    {
		      TREE_CHAIN (last) = void_list_node;
		      cp_error ("call of overloaded %s `%D(%A)' is ambiguous",
				name_kind, save_name, TREE_CHAIN (parmtypes));
		      print_n_candidates (candidates, n_candidates);
		    }
		  return error_mark_node;
		}
	      if (cp->h.code & EVIL_CODE)
		return error_mark_node;
	      if (warn_synth
		  && DECL_NAME (cp->function) == ansi_opname[MODIFY_EXPR]
		  && DECL_ARTIFICIAL (cp->function)
		  && n_candidates == 2)
		{
		  cp_warning ("using synthesized `%#D' for copy assignment",
			      cp->function);
		  cp_warning_at ("  where cfront would use `%#D'",
				 candidates->function);
		}
	    }
	  else if (cp[-1].h.code & EVIL_CODE)
	    {
	      if (flags & LOOKUP_COMPLAIN)
		cp_error ("ambiguous type conversion requested for %s `%D'",
			  name_kind, save_name);
	      return error_mark_node;
	    }
	  else
	    cp--;

	  /* The global function was the best, so use it.  */
	  if (cp->u.field == 0)
	    {
	      /* We must convert the instance pointer into a reference type.
		 Global overloaded functions can only either take
		 aggregate objects (which come for free from references)
		 or reference data types anyway.  */
	      TREE_VALUE (parms) = copy_node (instance_ptr);
	      TREE_TYPE (TREE_VALUE (parms)) = build_reference_type (TREE_TYPE (TREE_TYPE (instance_ptr)));
	      return build_function_call (cp->function, parms);
	    }

	  function = cp->function;
	  basetype_path = cp->basetypes;
	  if (! DECL_STATIC_FUNCTION_P (function))
	    TREE_VALUE (parms) = cp->arg;
	  goto found_and_maybe_warn;
	}

      if (flags & (LOOKUP_COMPLAIN|LOOKUP_SPECULATIVELY))
	{
	  if ((flags & (LOOKUP_SPECULATIVELY|LOOKUP_COMPLAIN))
	      == LOOKUP_SPECULATIVELY)
	    return NULL_TREE;

	  if (DECL_STATIC_FUNCTION_P (cp->function))
	    parms = TREE_CHAIN (parms);
	  if (ever_seen)
	    {
	      if (flags & LOOKUP_SPECULATIVELY)
		return NULL_TREE;
	      if (static_call_context
		  && TREE_CODE (TREE_TYPE (cp->function)) == METHOD_TYPE)
		cp_error ("object missing in call to `%D'", cp->function);
	      else if (ever_seen > 1)
		{
		  TREE_CHAIN (last) = void_list_node;
		  cp_error ("no matching function for call to `%T::%D (%A)%V'",
			    TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (instance_ptr))),
			    save_name, TREE_CHAIN (parmtypes),
			    TREE_TYPE (TREE_TYPE (instance_ptr)));
		  TREE_CHAIN (last) = NULL_TREE;
		  print_candidates (found_fns);
		}
	      else
		report_type_mismatch (cp, parms, name_kind);
	      return error_mark_node;
	    }

	  if ((flags & (LOOKUP_SPECULATIVELY|LOOKUP_COMPLAIN))
	      == LOOKUP_COMPLAIN)
	    {
	      cp_error ("%T has no method named %D", save_basetype, save_name);
	      return error_mark_node;
	    }
	  return NULL_TREE;
	}
      continue;

    found_and_maybe_warn:
      if ((cp->harshness[0].code & CONST_CODE)
	  /* 12.1p2: Constructors can be called for const objects.  */
	  && ! DECL_CONSTRUCTOR_P (cp->function))
	{
	  if (flags & LOOKUP_COMPLAIN)
	    {
	      cp_error_at ("non-const member function `%D'", cp->function);
	      error ("called for const object at this point in file");
	    }
	  /* Not good enough for a match.  */
	  else
	    return error_mark_node;
	}
      goto found;
    }
  /* Silently return error_mark_node.  */
  return error_mark_node;

 found:
  if (flags & LOOKUP_PROTECT)
    access = compute_access (basetype_path, function);

  if (access == access_private_node)
    {
      if (flags & LOOKUP_COMPLAIN)
	{
	  cp_error_at ("%s `%+#D' is %s", name_kind, function, 
		       TREE_PRIVATE (function) ? "private"
		       : "from private base class");
	  error ("within this context");
	}
      return error_mark_node;
    }
  else if (access == access_protected_node)
    {
      if (flags & LOOKUP_COMPLAIN)
	{
	  cp_error_at ("%s `%+#D' %s", name_kind, function,
		       TREE_PROTECTED (function) ? "is protected"
		       : "has protected accessibility");
	  error ("within this context");
	}
      return error_mark_node;
    }

  /* From here on down, BASETYPE is the type that INSTANCE_PTR's
     type (if it exists) is a pointer to.  */

  if (DECL_ABSTRACT_VIRTUAL_P (function)
      && instance == C_C_D
      && DECL_CONSTRUCTOR_P (current_function_decl)
      && ! (flags & LOOKUP_NONVIRTUAL)
      && value_member (function, get_abstract_virtuals (basetype)))
    cp_error ("abstract virtual `%#D' called from constructor", function);

  if (IS_SIGNATURE (basetype) && static_call_context)
    {
      cp_error ("cannot call signature member function `%T::%D' without signature pointer/reference",
		basetype, save_name);
      return error_mark_node;
	}
  else if (IS_SIGNATURE (basetype))
    return build_signature_method_call (basetype, instance, function, parms);

  function = DECL_MAIN_VARIANT (function);
  mark_used (function);

  /* Is it a synthesized method that needs to be synthesized?  */
  if (DECL_ARTIFICIAL (function) && ! DECL_INITIAL (function)
      /* Kludge: don't synthesize for default args.  */
      && current_function_decl)
    synthesize_method (function);

  if (pedantic && DECL_THIS_INLINE (function) && ! DECL_ARTIFICIAL (function)
       && ! DECL_INITIAL (function) && ! DECL_PENDING_INLINE_INFO (function))
    cp_warning ("inline function `%#D' called before definition", function);

  fntype = TREE_TYPE (function);
  if (TREE_CODE (fntype) == POINTER_TYPE)
    fntype = TREE_TYPE (fntype);
  basetype = DECL_CLASS_CONTEXT (function);

  /* If we are referencing a virtual function from an object
     of effectively static type, then there is no need
     to go through the virtual function table.  */
  if (need_vtbl == maybe_needed)
    {
      int fixed_type = resolves_to_fixed_type_p (instance, 0);

      if (all_virtual == 1
	  && DECL_VINDEX (function)
	  && may_be_remote (basetype))
	need_vtbl = needed;
      else if (DECL_VINDEX (function))
	need_vtbl = fixed_type ? unneeded : needed;
      else
	need_vtbl = not_needed;
    }

  if (TREE_CODE (fntype) == METHOD_TYPE && static_call_context
      && !DECL_CONSTRUCTOR_P (function))
    {
      /* Let's be nasty to the user now, and give reasonable
	 error messages.  */
      instance_ptr = current_class_decl;
      if (instance_ptr)
	{
	  if (basetype != current_class_type)
	    {
	      if (basetype == error_mark_node)
		return error_mark_node;
	      else 
                {
		  if (orig_basetype != NULL_TREE)
		    error_not_base_type (orig_basetype, current_class_type);
		  else
		    error_not_base_type (function, current_class_type);
                  return error_mark_node;
                }
	    }
	}
      /* Only allow a static member function to call another static member
	 function.  */
      else if (DECL_LANG_SPECIFIC (function)
	       && !DECL_STATIC_FUNCTION_P (function))
	{
	  cp_error ("cannot call member function `%D' without object",
		    function);
	  return error_mark_node;
	}
    }

  value_type = TREE_TYPE (fntype) ? TREE_TYPE (fntype) : void_type_node;

  if (TYPE_SIZE (complete_type (value_type)) == 0)
    {
      if (flags & LOOKUP_COMPLAIN)
	incomplete_type_error (0, value_type);
      return error_mark_node;
    }

  if (DECL_STATIC_FUNCTION_P (function))
    parms = convert_arguments (NULL_TREE, TYPE_ARG_TYPES (fntype),
			       TREE_CHAIN (parms), function, LOOKUP_NORMAL);
  else if (need_vtbl == unneeded)
    {
      int sub_flags = DECL_CONSTRUCTOR_P (function) ? flags : LOOKUP_NORMAL;
      basetype = TREE_TYPE (instance);
      if (TYPE_METHOD_BASETYPE (TREE_TYPE (function)) != TYPE_MAIN_VARIANT (basetype)
	  && TYPE_USES_COMPLEX_INHERITANCE (basetype))
	{
	  basetype = DECL_CLASS_CONTEXT (function);
	  instance_ptr = convert_pointer_to (basetype, instance_ptr);
	  instance = build_indirect_ref (instance_ptr, NULL_PTR);
	}
      parms = tree_cons (NULL_TREE, instance_ptr,
			 convert_arguments (NULL_TREE, TREE_CHAIN (TYPE_ARG_TYPES (fntype)), TREE_CHAIN (parms), function, sub_flags));
    }
  else
    {
      if ((flags & LOOKUP_NONVIRTUAL) == 0)
	basetype = DECL_CONTEXT (function);

      /* First parm could be integer_zerop with casts like
	 ((Object*)0)->Object::IsA()  */
      if (!integer_zerop (TREE_VALUE (parms)))
	{
	  /* Since we can't have inheritance with a union, doing get_binfo
	     on it won't work.  We do all the convert_pointer_to_real
	     stuff to handle MI correctly...for unions, that's not
	     an issue, so we must short-circuit that extra work here.  */
	  tree tmp = TREE_TYPE (TREE_TYPE (TREE_VALUE (parms)));
	  if (tmp != NULL_TREE && TREE_CODE (tmp) == UNION_TYPE)
	    instance_ptr = TREE_VALUE (parms);
	  else
	    {
	      tree binfo = get_binfo (basetype,
				      TREE_TYPE (TREE_TYPE (TREE_VALUE (parms))),
				      0);
	      instance_ptr = convert_pointer_to_real (binfo, TREE_VALUE (parms));
	    }
	  instance_ptr
	    = convert_pointer_to (build_type_variant (basetype,
						      constp, volatilep),
				  instance_ptr);

	  if (TREE_CODE (instance_ptr) == COND_EXPR)
	    {
	      instance_ptr = save_expr (instance_ptr);
	      instance = build_indirect_ref (instance_ptr, NULL_PTR);
	    }
	  else if (TREE_CODE (instance_ptr) == NOP_EXPR
		   && TREE_CODE (TREE_OPERAND (instance_ptr, 0)) == ADDR_EXPR
		   && TREE_OPERAND (TREE_OPERAND (instance_ptr, 0), 0) == instance)
	    ;
	  /* The call to `convert_pointer_to' may return error_mark_node.  */
	  else if (TREE_CODE (instance_ptr) == ERROR_MARK)
	    return instance_ptr;
	  else if (instance == NULL_TREE
		   || TREE_CODE (instance) != INDIRECT_REF
		   || TREE_OPERAND (instance, 0) != instance_ptr)
	    instance = build_indirect_ref (instance_ptr, NULL_PTR);
	}
      parms = tree_cons (NULL_TREE, instance_ptr,
			 convert_arguments (NULL_TREE, TREE_CHAIN (TYPE_ARG_TYPES (fntype)), TREE_CHAIN (parms), function, LOOKUP_NORMAL));
    }

  if (parms == error_mark_node
      || (parms && TREE_CHAIN (parms) == error_mark_node))
    return error_mark_node;

  if (need_vtbl == needed)
    {
      function = build_vfn_ref (&TREE_VALUE (parms), instance,
				DECL_VINDEX (function));
      TREE_TYPE (function) = build_pointer_type (fntype);
    }

  if (TREE_CODE (function) == FUNCTION_DECL)
    GNU_xref_call (current_function_decl,
		   IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (function)));

  {
    int is_constructor;
    
    if (TREE_CODE (function) == FUNCTION_DECL)
      {
	is_constructor = DECL_CONSTRUCTOR_P (function);
	function = default_conversion (function);
      }
    else
      {
	is_constructor = 0;
	function = default_conversion (function);
      }

    result = build_nt (CALL_EXPR, function, parms, NULL_TREE);

    TREE_TYPE (result) = value_type;
    TREE_SIDE_EFFECTS (result) = 1;
    TREE_HAS_CONSTRUCTOR (result) = is_constructor;
    result = convert_from_reference (result);
    return result;
  }
}

/* Similar to `build_method_call', but for overloaded non-member functions.
   The name of this function comes through NAME.  The name depends
   on PARMS.

   Note that this function must handle simple `C' promotions,
   as well as variable numbers of arguments (...), and
   default arguments to boot.

   If the overloading is successful, we return a tree node which
   contains the call to the function.

   If overloading produces candidates which are probable, but not definite,
   we hold these candidates.  If FINAL_CP is non-zero, then we are free
   to assume that final_cp points to enough storage for all candidates that
   this function might generate.  The `harshness' array is preallocated for
   the first candidate, but not for subsequent ones.

   Note that the DECL_RTL of FUNCTION must be made to agree with this
   function's new name.  */

tree
build_overload_call_real (fnname, parms, flags, final_cp, buildxxx)
     tree fnname, parms;
     int flags;
     struct candidate *final_cp;
     int buildxxx;
{
  /* must check for overloading here */
  tree functions, function, parm;
  tree parmtypes = NULL_TREE, last = NULL_TREE;
  register tree outer;
  int length;
  int parmlength = list_length (parms);

  struct candidate *candidates, *cp;

  if (final_cp)
    {
      final_cp[0].h.code = 0;
      final_cp[0].h.distance = 0;
      final_cp[0].function = 0;
      /* end marker.  */
      final_cp[1].h.code = EVIL_CODE;
    }

  for (parm = parms; parm; parm = TREE_CHAIN (parm))
    {
      register tree t = TREE_TYPE (TREE_VALUE (parm));

      if (t == error_mark_node)
	{
	  if (final_cp)
	    final_cp->h.code = EVIL_CODE;
	  return error_mark_node;
	}
      if (TREE_CODE (t) == OFFSET_TYPE)
#if 0
      /* This breaks reference-to-array parameters.  */
	  || TREE_CODE (t) == ARRAY_TYPE
#endif
	{
	  /* Perform the conversion from ARRAY_TYPE to POINTER_TYPE in place.
	     Also convert OFFSET_TYPE entities to their normal selves.
	     This eliminates needless calls to `compute_conversion_costs'.  */
	  TREE_VALUE (parm) = default_conversion (TREE_VALUE (parm));
	  t = TREE_TYPE (TREE_VALUE (parm));
	}
      last = build_tree_list (NULL_TREE, t);
      parmtypes = chainon (parmtypes, last);
    }
  if (last)
    TREE_CHAIN (last) = void_list_node;
  else
    parmtypes = void_list_node;

  if (is_overloaded_fn (fnname))
    {
      functions = fnname;
      if (TREE_CODE (fnname) == TREE_LIST)
	fnname = TREE_PURPOSE (functions);
      else if (TREE_CODE (fnname) == FUNCTION_DECL)
	fnname = DECL_NAME (functions);
    }
  else 
    functions = lookup_name_nonclass (fnname);

  if (functions == NULL_TREE)
    {
      if (flags & LOOKUP_SPECULATIVELY)
	return NULL_TREE;
      if (flags & LOOKUP_COMPLAIN)
	error ("only member functions apply");
      if (final_cp)
	final_cp->h.code = EVIL_CODE;
      return error_mark_node;
    }

  if (TREE_CODE (functions) == FUNCTION_DECL && ! IDENTIFIER_OPNAME_P (fnname))
    {
      functions = DECL_MAIN_VARIANT (functions);
      if (final_cp)
	{
	  /* We are just curious whether this is a viable alternative or
             not.  */
	  compute_conversion_costs (functions, parms, final_cp, parmlength);
	  return functions;
	}
      else
	return build_function_call_real (functions, parms, 1, flags);
    }

  if (TREE_CODE (functions) == TREE_LIST
      && TREE_VALUE (functions) == NULL_TREE)
    {
      if (flags & LOOKUP_SPECULATIVELY)
	return NULL_TREE;
      
      if (flags & LOOKUP_COMPLAIN)
	cp_error ("function `%D' declared overloaded, but no instances of that function declared",
		  TREE_PURPOSE (functions));
      if (final_cp)
	final_cp->h.code = EVIL_CODE;
      return error_mark_node;
    }

  length = count_functions (functions);
  
  if (final_cp)
    candidates = final_cp;
  else
    {
      candidates
	= (struct candidate *)alloca ((length+1) * sizeof (struct candidate));
      bzero ((char *) candidates, (length + 1) * sizeof (struct candidate));
    }

  cp = candidates;

  my_friendly_assert (is_overloaded_fn (functions), 169);

  functions = get_first_fn (functions);

  /* OUTER is the list of FUNCTION_DECLS, in a TREE_LIST.  */
  for (outer = functions; outer; outer = DECL_CHAIN (outer))
    {
      int template_cost = 0;
      function = outer;
      if (TREE_CODE (function) != FUNCTION_DECL
	  && ! (TREE_CODE (function) == TEMPLATE_DECL
		&& TREE_CODE (DECL_TEMPLATE_RESULT (function)) == FUNCTION_DECL))
	{
	  enum tree_code code = TREE_CODE (function);
	  if (code == TEMPLATE_DECL)
	    code = TREE_CODE (DECL_TEMPLATE_RESULT (function));
	  if (code == CONST_DECL)
	    cp_error_at
	      ("enumeral value `%D' conflicts with function of same name",
	       function);
	  else if (code == VAR_DECL)
	    {
	      if (TREE_STATIC (function))
		cp_error_at
		  ("variable `%D' conflicts with function of same name",
		   function);
	      else
		cp_error_at
		  ("constant field `%D' conflicts with function of same name",
		   function);
	    }
	  else if (code == TYPE_DECL)
	    continue;
	  else
	    my_friendly_abort (2);
	  error ("at this point in file");
	  continue;
	}
      if (TREE_CODE (function) == TEMPLATE_DECL)
	{
	  int ntparms = TREE_VEC_LENGTH (DECL_TEMPLATE_PARMS (function));
	  tree *targs = (tree *) alloca (sizeof (tree) * ntparms);
	  int i;

	  i = type_unification (DECL_TEMPLATE_PARMS (function), targs,
				TYPE_ARG_TYPES (TREE_TYPE (function)),
				parms, &template_cost, 0);
	  if (i == 0)
	    {
	      function = instantiate_template (function, targs);
	      if (function == error_mark_node)
		return function;
	    }
	}

      if (TREE_CODE (function) == TEMPLATE_DECL)
	{
	  /* Unconverted template -- failed match.  */
	  cp->function = function;
	  cp->u.bad_arg = -4;
	  cp->h.code = EVIL_CODE;
	}
      else
	{
	  struct candidate *cp2;

	  /* Check that this decl is not the same as a function that's in
	     the list due to some template instantiation.  */
	  cp2 = candidates;
	  while (cp2 != cp)
	    if (cp2->function == function)
	      break;
	    else
	      cp2 += 1;
	  if (cp2->function == function)
	    continue;

	  function = DECL_MAIN_VARIANT (function);

	  /* Can't use alloca here, since result might be
	     passed to calling function.  */
	  cp->h_len = parmlength;
	  cp->harshness = (struct harshness_code *)
	    oballoc ((parmlength + 1) * sizeof (struct harshness_code));

	  compute_conversion_costs (function, parms, cp, parmlength);

	  /* Make sure this is clear as well.  */
	  cp->h.int_penalty += template_cost;

	  if ((cp[0].h.code & EVIL_CODE) == 0)
	    {
	      cp[1].h.code = EVIL_CODE;
	      cp++;
	    }
	}
    }

  if (cp - candidates)
    {
      tree rval = error_mark_node;

      /* Leave marker.  */
      cp[0].h.code = EVIL_CODE;
      if (cp - candidates > 1)
	{
	  struct candidate *best_cp
	    = ideal_candidate (candidates, cp - candidates, parmlength);
	  if (best_cp == (struct candidate *)0)
	    {
	      if (flags & LOOKUP_COMPLAIN)
		{
		  cp_error ("call of overloaded `%D' is ambiguous", fnname);
		  print_n_candidates (candidates, cp - candidates);
		}
	      return error_mark_node;
	    }
	  else
	    rval = best_cp->function;
	}
      else
	{
	  cp -= 1;
	  if (cp->h.code & EVIL_CODE)
	    {
	      if (flags & LOOKUP_COMPLAIN)
		error ("type conversion ambiguous");
	    }
	  else
	    rval = cp->function;
	}

      if (final_cp)
	return rval;

      return buildxxx ? build_function_call_real (rval, parms, 0, flags)
        : build_function_call_real (rval, parms, 1, flags);
    }

  if (flags & LOOKUP_SPECULATIVELY)
    return NULL_TREE;
  
  if (flags & LOOKUP_COMPLAIN)
    report_type_mismatch (cp, parms, "function",
			  decl_as_string (cp->function, 1));

  return error_mark_node;
}

tree
build_overload_call (fnname, parms, flags, final_cp)
     tree fnname, parms;
     int flags;
     struct candidate *final_cp;
{
  return build_overload_call_real (fnname, parms, flags, final_cp, 0);
}

tree
build_overload_call_maybe (fnname, parms, flags, final_cp)
     tree fnname, parms;
     int flags;
     struct candidate *final_cp;
{
  return build_overload_call_real (fnname, parms, flags, final_cp, 1);
}
