function.c (update_temp_slot_address): Handle case where sum of temporary address...

[thirdparty/gcc.git] / gcc / cp / class.c

/* Functions related to building classes and their related objects.
   Copyright (C) 1987, 92-97, 1998, 1999 Free Software Foundation, Inc.
   Contributed by Michael Tiemann (tiemann@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 "system.h"
#include "tree.h"
#include "cp-tree.h"
#include "flags.h"
#include "rtl.h"
#include "output.h"
#include "toplev.h"
#include "ggc.h"
#include "lex.h"

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

/* This is how we tell when two virtual member functions are really the
   same.  */
#define SAME_FN(FN1DECL, FN2DECL) (DECL_ASSEMBLER_NAME (FN1DECL) == DECL_ASSEMBLER_NAME (FN2DECL))

extern void set_class_shadows PROTO ((tree));

/* The number of nested classes being processed.  If we are not in the
   scope of any class, this is zero.  */

int current_class_depth;

/* In order to deal with nested classes, we keep a stack of classes.
   The topmost entry is the innermost class, and is the entry at index
   CURRENT_CLASS_DEPTH  */

typedef struct class_stack_node {
  /* The name of the class.  */
  tree name;

  /* The _TYPE node for the class.  */
  tree type;

  /* The access specifier pending for new declarations in the scope of
     this class.  */
  tree access;

  /* If were defining TYPE, the names used in this class.  */
  splay_tree names_used;
}* class_stack_node_t;

/* The stack itself.  This is an dynamically resized array.  The
   number of elements allocated is CURRENT_CLASS_STACK_SIZE.  */
static int current_class_stack_size;
static class_stack_node_t current_class_stack;

struct base_info;

static tree get_vfield_name PROTO((tree));
static void finish_struct_anon PROTO((tree));
static tree build_vbase_pointer PROTO((tree, tree));
static tree build_vtable_entry PROTO((tree, tree));
static tree get_vtable_name PROTO((tree));
static tree get_derived_offset PROTO((tree, tree));
static tree get_basefndecls PROTO((tree, tree));
static void set_rtti_entry PROTO((tree, tree, tree));
static tree build_vtable PROTO((tree, tree));
static void prepare_fresh_vtable PROTO((tree, tree));
static void fixup_vtable_deltas1 PROTO((tree, tree));
static void fixup_vtable_deltas PROTO((tree, int, tree));
static void finish_vtbls PROTO((tree, int, tree));
static void modify_vtable_entry PROTO((tree, tree, tree));
static tree get_vtable_entry_n PROTO((tree, unsigned HOST_WIDE_INT));
static void add_virtual_function PROTO((tree *, tree *, int *, tree, tree));
static tree delete_duplicate_fields_1 PROTO((tree, tree));
static void delete_duplicate_fields PROTO((tree));
static void finish_struct_bits PROTO((tree, int));
static int alter_access PROTO((tree, tree, tree, tree));
static void handle_using_decl PROTO((tree, tree));
static int overrides PROTO((tree, tree));
static int strictly_overrides PROTO((tree, tree));
static void merge_overrides PROTO((tree, tree, int, tree));
static void override_one_vtable PROTO((tree, tree, tree));
static void mark_overriders PROTO((tree, tree));
static void check_for_override PROTO((tree, tree));
static tree get_class_offset_1 PROTO((tree, tree, tree, tree, tree));
static tree get_class_offset PROTO((tree, tree, tree, tree));
static void modify_one_vtable PROTO((tree, tree, tree));
static void modify_all_vtables PROTO((tree, tree));
static void modify_all_direct_vtables PROTO((tree, int, tree, tree));
static void modify_all_indirect_vtables PROTO((tree, int, int, tree, tree));
static int finish_base_struct PROTO((tree, struct base_info *));
static void finish_struct_methods PROTO((tree));
static void maybe_warn_about_overly_private_class PROTO ((tree));
static int field_decl_cmp PROTO ((const tree *, const tree *));
static int method_name_cmp PROTO ((const tree *, const tree *));
static tree add_implicitly_declared_members PROTO((tree, int, int, int));
static tree fixed_type_or_null PROTO((tree, int *));
static tree resolve_address_of_overloaded_function PROTO((tree, tree, int,
							  int, tree));
static void build_vtable_entry_ref PROTO((tree, tree, tree));
static tree build_vtable_entry_for_fn PROTO((tree, tree));
static tree build_vtbl_initializer PROTO((tree));
static int count_fields PROTO((tree));
static int add_fields_to_vec PROTO((tree, tree, int));
static void check_bitfield_decl PROTO((tree));
static void check_field_decl PROTO((tree, tree, int *, int *, int *, int *));
static void check_field_decls PROTO((tree, tree *, int *, int *, int *, 
				     int *));
static int avoid_overlap PROTO((tree, tree, int *));
static tree build_base_fields PROTO((tree, int *));
static tree build_vbase_pointer_fields PROTO((tree, int *));
static tree build_vtbl_or_vbase_field PROTO((tree, tree, tree, tree, int *));
static void check_methods PROTO((tree));
static void remove_zero_width_bit_fields PROTO((tree));
static void check_bases PROTO((tree, int *, int *, int *));
static void check_bases_and_members PROTO((tree, int *));
static void create_vtable_ptr PROTO((tree, int *, int *, int *, tree *, tree *));
static void layout_class_type PROTO((tree, int *, int *, int *, tree *, tree *));
static void fixup_pending_inline PROTO((struct pending_inline *));
static void fixup_inline_methods PROTO((tree));

/* Variables shared between class.c and call.c.  */

#ifdef GATHER_STATISTICS
int n_vtables = 0;
int n_vtable_entries = 0;
int n_vtable_searches = 0;
int n_vtable_elems = 0;
int n_convert_harshness = 0;
int n_compute_conversion_costs = 0;
int n_build_method_call = 0;
int n_inner_fields_searched = 0;
#endif

/* Virtual baseclass things.  */

static tree
build_vbase_pointer (exp, type)
     tree exp, type;
{
  char *name;
  FORMAT_VBASE_NAME (name, type);

  return build_component_ref (exp, get_identifier (name), NULL_TREE, 0);
}

#if 0
/* Is the type of the EXPR, the complete type of the object?
   If we are going to be wrong, we must be conservative, and return 0.  */

static int
complete_type_p (expr)
     tree expr;
{
  tree type = TYPE_MAIN_VARIANT (TREE_TYPE (expr));
  while (1)
    {
      switch (TREE_CODE (expr))
	{
	case SAVE_EXPR:
	case INDIRECT_REF:
	case ADDR_EXPR:
	case NOP_EXPR:
	case CONVERT_EXPR:
	  expr = TREE_OPERAND (expr, 0);
	  continue;

	case CALL_EXPR: 
	  if (! TREE_HAS_CONSTRUCTOR (expr))
	    break;
	  /* fall through...  */
	case VAR_DECL:
	case FIELD_DECL:
	  if (TREE_CODE (TREE_TYPE (expr)) == ARRAY_TYPE
	      && IS_AGGR_TYPE (TREE_TYPE (TREE_TYPE (expr)))
	      && TYPE_MAIN_VARIANT (TREE_TYPE (expr)) == type)
	    return 1;
	  /* fall through...  */
	case TARGET_EXPR:
	case PARM_DECL:
	  if (IS_AGGR_TYPE (TREE_TYPE (expr))
	      && TYPE_MAIN_VARIANT (TREE_TYPE (expr)) == type)
	    return 1;
	  /* fall through...  */
	case PLUS_EXPR:
	default:
	  break;
	}
      break;
    }
  return 0;
}
#endif

/* Build multi-level access to EXPR using hierarchy path PATH.
   CODE is PLUS_EXPR if we are going with the grain,
   and MINUS_EXPR if we are not (in which case, we cannot traverse
   virtual baseclass links).

   TYPE is the type we want this path to have on exit.

   NONNULL is non-zero if  we know (for any reason) that EXPR is
   not, in fact, zero.  */

tree
build_vbase_path (code, type, expr, path, nonnull)
     enum tree_code code;
     tree type, expr, path;
     int nonnull;
{
  register int changed = 0;
  tree last = NULL_TREE, last_virtual = NULL_TREE;
  int fixed_type_p;
  tree null_expr = 0, nonnull_expr;
  tree basetype;
  tree offset = integer_zero_node;

  if (BINFO_INHERITANCE_CHAIN (path) == NULL_TREE)
    return build1 (NOP_EXPR, type, expr);

  /* We could do better if we had additional logic to convert back to the
     unconverted type (the static type of the complete object), and then
     convert back to the type we want.  Until that is done, we only optimize
     if the complete type is the same type as expr has.  */
  fixed_type_p = resolves_to_fixed_type_p (expr, &nonnull);

  if (!fixed_type_p && TREE_SIDE_EFFECTS (expr))
    expr = save_expr (expr);
  nonnull_expr = expr;

  if (BINFO_INHERITANCE_CHAIN (path))
    path = reverse_path (path);

  basetype = BINFO_TYPE (path);

  while (path)
    {
      if (TREE_VIA_VIRTUAL (path))
	{
	  last_virtual = BINFO_TYPE (path);
	  if (code == PLUS_EXPR)
	    {
	      changed = ! fixed_type_p;

	      if (changed)
		{
		  tree ind;

		  /* We already check for ambiguous things in the caller, just
		     find a path.  */
		  if (last)
		    {
		      tree binfo = get_binfo (last, TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (nonnull_expr))), 0);
		      nonnull_expr = convert_pointer_to_real (binfo, nonnull_expr);
		    }
		  ind = build_indirect_ref (nonnull_expr, NULL_PTR);
		  nonnull_expr = build_vbase_pointer (ind, last_virtual);
		  if (nonnull == 0
		      && TREE_CODE (type) == POINTER_TYPE
		      && null_expr == NULL_TREE)
		    {
		      null_expr = build1 (NOP_EXPR, build_pointer_type (last_virtual), integer_zero_node);
		      expr = build (COND_EXPR, build_pointer_type (last_virtual),
				    build (EQ_EXPR, boolean_type_node, expr,
					   integer_zero_node),
				    null_expr, nonnull_expr);
		    }
		}
	      /* else we'll figure out the offset below.  */

	      /* Happens in the case of parse errors.  */
	      if (nonnull_expr == error_mark_node)
		return error_mark_node;
	    }
	  else
	    {
	      cp_error ("cannot cast up from virtual baseclass `%T'",
			  last_virtual);
	      return error_mark_node;
	    }
	}
      last = path;
      path = BINFO_INHERITANCE_CHAIN (path);
    }
  /* LAST is now the last basetype assoc on the path.  */

  /* A pointer to a virtual base member of a non-null object
     is non-null.  Therefore, we only need to test for zeroness once.
     Make EXPR the canonical expression to deal with here.  */
  if (null_expr)
    {
      TREE_OPERAND (expr, 2) = nonnull_expr;
      TREE_TYPE (expr) = TREE_TYPE (TREE_OPERAND (expr, 1))
	= TREE_TYPE (nonnull_expr);
    }
  else
    expr = nonnull_expr;

  /* If we go through any virtual base pointers, make sure that
     casts to BASETYPE from the last virtual base class use
     the right value for BASETYPE.  */
  if (changed)
    {
      tree intype = TREE_TYPE (TREE_TYPE (expr));
      if (TYPE_MAIN_VARIANT (intype) != BINFO_TYPE (last))
	{
	  tree binfo = get_binfo (last, TYPE_MAIN_VARIANT (intype), 0);
	  offset = BINFO_OFFSET (binfo);
	}
    }
  else
    {
      if (last_virtual)
	{
	  offset = BINFO_OFFSET (BINFO_FOR_VBASE (last_virtual, 
						  basetype));
	  offset = size_binop (PLUS_EXPR, offset, BINFO_OFFSET (last));
	}
      else
	offset = BINFO_OFFSET (last);
    }

  if (TREE_INT_CST_LOW (offset))
    {
      /* Bash types to make the backend happy.  */
      offset = cp_convert (type, offset);
#if 0
      /* This shouldn't be necessary.  (mrs) */
      expr = build1 (NOP_EXPR, type, expr);
#endif

      /* If expr might be 0, we need to preserve that zeroness.  */
      if (nonnull == 0)
	{
	  if (null_expr)
	    TREE_TYPE (null_expr) = type;
	  else
	    null_expr = build1 (NOP_EXPR, type, integer_zero_node);
	  if (TREE_SIDE_EFFECTS (expr))
	    expr = save_expr (expr);

	  return build (COND_EXPR, type,
			build (EQ_EXPR, boolean_type_node, expr, integer_zero_node),
			null_expr,
			build (code, type, expr, offset));
	}
      else return build (code, type, expr, offset);
    }

  /* Cannot change the TREE_TYPE of a NOP_EXPR here, since it may
     be used multiple times in initialization of multiple inheritance.  */
  if (null_expr)
    {
      TREE_TYPE (expr) = type;
      return expr;
    }
  else
    return build1 (NOP_EXPR, type, expr);
}

/* Virtual function things.  */

/* Build an entry in the virtual function table.
   DELTA is the offset for the `this' pointer.
   PFN is an ADDR_EXPR containing a pointer to the virtual function.
   Note that the index (DELTA2) in the virtual function table
   is always 0.  */

static tree
build_vtable_entry (delta, pfn)
     tree delta, pfn;
{
  if (flag_vtable_thunks)
    {
      HOST_WIDE_INT idelta = TREE_INT_CST_LOW (delta);
      if (idelta && ! DECL_PURE_VIRTUAL_P (TREE_OPERAND (pfn, 0)))
	{
	  pfn = build1 (ADDR_EXPR, vtable_entry_type,
			make_thunk (pfn, idelta));
	  TREE_READONLY (pfn) = 1;
	  TREE_CONSTANT (pfn) = 1;
	}
#ifdef GATHER_STATISTICS
      n_vtable_entries += 1;
#endif
      return pfn;
    }
  else
    {
      extern int flag_huge_objects;
      tree elems = tree_cons (NULL_TREE, delta,
			      tree_cons (NULL_TREE, integer_zero_node,
					 build_expr_list (NULL_TREE, pfn)));
      tree entry = build (CONSTRUCTOR, vtable_entry_type, NULL_TREE, elems);

      /* DELTA used to be constructed by `size_int' and/or size_binop,
	 which caused overflow problems when it was negative.  That should
	 be fixed now.  */

      if (! int_fits_type_p (delta, delta_type_node))
	{
	  if (flag_huge_objects)
	    sorry ("object size exceeds built-in limit for virtual function table implementation");
	  else
	    sorry ("object size exceeds normal limit for virtual function table implementation, recompile all source and use -fhuge-objects");
	}
      
      TREE_CONSTANT (entry) = 1;
      TREE_STATIC (entry) = 1;
      TREE_READONLY (entry) = 1;

#ifdef GATHER_STATISTICS
      n_vtable_entries += 1;
#endif

      return entry;
    }
}

/* Build a vtable entry for FNDECL.  DELTA is the amount by which we
   must adjust the this pointer when calling F.  */

static tree
build_vtable_entry_for_fn (delta, fndecl)
     tree delta;
     tree fndecl;
{
  tree pfn;

  /* Take the address of the function, considering it to be of an
     appropriate generic type.  */
  pfn = build1 (ADDR_EXPR, vfunc_ptr_type_node, fndecl);
  /* The address of a function can't change.  */
  TREE_CONSTANT (pfn) = 1;
  /* Now build the vtable entry itself.  */
  return build_vtable_entry (delta, pfn);
}

/* We want to give the assembler the vtable identifier as well as
   the offset to the function pointer.  So we generate

   __asm__ __volatile__ (".vtable_entry %c0, %c1"
      : : "s"(&class_vtable),
          "i"((long)&vtbl[idx].pfn - (long)&vtbl[0])); */

static void
build_vtable_entry_ref (basetype, vtbl, idx)
     tree basetype, vtbl, idx;
{
  static char asm_stmt[] = ".vtable_entry %c0, %c1";
  tree s, i, i2;

  s = build_unary_op (ADDR_EXPR, TYPE_BINFO_VTABLE (basetype), 0);
  s = build_tree_list (build_string (1, "s"), s);

  i = build_array_ref (vtbl, idx);
  if (!flag_vtable_thunks)
    i = build_component_ref (i, pfn_identifier, vtable_entry_type, 0);
  i = build_c_cast (ptrdiff_type_node, build_unary_op (ADDR_EXPR, i, 0));
  i2 = build_array_ref (vtbl, build_int_2(0,0));
  i2 = build_c_cast (ptrdiff_type_node, build_unary_op (ADDR_EXPR, i2, 0));
  i = build_binary_op (MINUS_EXPR, i, i2);
  i = build_tree_list (build_string (1, "i"), i);

  finish_asm_stmt (ridpointers[RID_VOLATILE],
		   build_string (sizeof(asm_stmt)-1, asm_stmt),
		   NULL_TREE, chainon (s, i), NULL_TREE);
}

/* Given an object INSTANCE, return an expression which yields the
   virtual function vtable element corresponding to INDEX.  There are
   many special cases for INSTANCE which we take care of here, mainly
   to avoid creating extra tree nodes when we don't have to.  */

tree
build_vtbl_ref (instance, idx)
     tree instance, idx;
{
  tree vtbl, aref;
  tree basetype = TREE_TYPE (instance);

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

  if (instance == current_class_ref)
    vtbl = build_vfield_ref (instance, basetype);
  else
    {
      if (optimize)
	{
	  /* Try to figure out what a reference refers to, and
	     access its virtual function table directly.  */
	  tree ref = NULL_TREE;

	  if (TREE_CODE (instance) == INDIRECT_REF
	      && TREE_CODE (TREE_TYPE (TREE_OPERAND (instance, 0))) == REFERENCE_TYPE)
	    ref = TREE_OPERAND (instance, 0);
	  else if (TREE_CODE (TREE_TYPE (instance)) == REFERENCE_TYPE)
	    ref = instance;

	  if (ref && TREE_CODE (ref) == VAR_DECL
	      && DECL_INITIAL (ref))
	    {
	      tree init = DECL_INITIAL (ref);

	      while (TREE_CODE (init) == NOP_EXPR
		     || TREE_CODE (init) == NON_LVALUE_EXPR)
		init = TREE_OPERAND (init, 0);
	      if (TREE_CODE (init) == ADDR_EXPR)
		{
		  init = TREE_OPERAND (init, 0);
		  if (IS_AGGR_TYPE (TREE_TYPE (init))
		      && (TREE_CODE (init) == PARM_DECL
			  || TREE_CODE (init) == VAR_DECL))
		    instance = init;
		}
	    }
	}

      if (IS_AGGR_TYPE (TREE_TYPE (instance))
	  && (TREE_CODE (instance) == RESULT_DECL
	      || TREE_CODE (instance) == PARM_DECL
	      || TREE_CODE (instance) == VAR_DECL))
	vtbl = TYPE_BINFO_VTABLE (basetype);
      else
	vtbl = build_vfield_ref (instance, basetype);
    }

  assemble_external (vtbl);

  if (flag_vtable_gc)
    build_vtable_entry_ref (basetype, vtbl, idx);

  aref = build_array_ref (vtbl, idx);

  return aref;
}

/* Given an object INSTANCE, return an expression which yields the
   virtual function corresponding to INDEX.  There are many special
   cases for INSTANCE which we take care of here, mainly to avoid
   creating extra tree nodes when we don't have to.  */

tree
build_vfn_ref (ptr_to_instptr, instance, idx)
     tree *ptr_to_instptr, instance;
     tree idx;
{
  tree aref = build_vtbl_ref (instance, idx);

  /* When using thunks, there is no extra delta, and we get the pfn
     directly.  */
  if (flag_vtable_thunks)
    return aref;

  if (ptr_to_instptr)
    {
      /* Save the intermediate result in a SAVE_EXPR so we don't have to
	 compute each component of the virtual function pointer twice.  */ 
      if (TREE_CODE (aref) == INDIRECT_REF)
	TREE_OPERAND (aref, 0) = save_expr (TREE_OPERAND (aref, 0));

      *ptr_to_instptr
	= build (PLUS_EXPR, TREE_TYPE (*ptr_to_instptr),
		 *ptr_to_instptr,
		 cp_convert (ptrdiff_type_node,
			     build_component_ref (aref, delta_identifier, NULL_TREE, 0)));
    }

  return build_component_ref (aref, pfn_identifier, NULL_TREE, 0);
}

/* Return the name of the virtual function table (as an IDENTIFIER_NODE)
   for the given TYPE.  */

static tree
get_vtable_name (type)
     tree type;
{
  tree type_id = build_typename_overload (type);
  char *buf = (char *) alloca (strlen (VTABLE_NAME_PREFIX)
			       + IDENTIFIER_LENGTH (type_id) + 2);
  const char *ptr = IDENTIFIER_POINTER (type_id);
  int i;
  for (i = 0; ptr[i] == OPERATOR_TYPENAME_FORMAT[i]; i++) ;
#if 0
  /* We don't take off the numbers; prepare_fresh_vtable uses the
     DECL_ASSEMBLER_NAME for the type, which includes the number
     in `3foo'.  If we were to pull them off here, we'd end up with
     something like `_vt.foo.3bar', instead of a uniform definition.  */
  while (ptr[i] >= '0' && ptr[i] <= '9')
    i += 1;
#endif
  sprintf (buf, "%s%s", VTABLE_NAME_PREFIX, ptr+i);
  return get_identifier (buf);
}

/* Return the offset to the main vtable for a given base BINFO.  */

tree
get_vfield_offset (binfo)
     tree binfo;
{
  tree tmp
    = size_binop (FLOOR_DIV_EXPR,
		  DECL_FIELD_BITPOS (TYPE_VFIELD (BINFO_TYPE (binfo))),
		  size_int (BITS_PER_UNIT));
  tmp = convert (sizetype, tmp);
  return size_binop (PLUS_EXPR, tmp, BINFO_OFFSET (binfo));
}

/* Get the offset to the start of the original binfo that we derived
   this binfo from.  If we find TYPE first, return the offset only
   that far.  The shortened search is useful because the this pointer
   on method calling is expected to point to a DECL_CONTEXT (fndecl)
   object, and not a baseclass of it.  */

static tree
get_derived_offset (binfo, type)
     tree binfo, type;
{
  tree offset1 = get_vfield_offset (TYPE_BINFO (BINFO_TYPE (binfo)));
  tree offset2;
  int i;
  while (BINFO_BASETYPES (binfo)
	 && (i=CLASSTYPE_VFIELD_PARENT (BINFO_TYPE (binfo))) != -1)
    {
      tree binfos = BINFO_BASETYPES (binfo);
      if (BINFO_TYPE (binfo) == type)
	break;
      binfo = TREE_VEC_ELT (binfos, i);
    }
  offset2 = get_vfield_offset (TYPE_BINFO (BINFO_TYPE (binfo)));
  return size_binop (MINUS_EXPR, offset1, offset2);
}

/* Update the rtti info for this class.  */

static void
set_rtti_entry (virtuals, offset, type)
     tree virtuals, offset, type;
{
  tree fn;

  if (CLASSTYPE_COM_INTERFACE (type))
    return;

  if (flag_rtti)
    fn = get_tinfo_fn_unused (type);
  else
    /* If someone tries to get RTTI information for a type compiled
       without RTTI, they're out of luck.  By calling __pure_virtual
       in this case, we give a small clue as to what went wrong.  We
       could consider having a __no_typeinfo function as well, for a
       more specific hint.  */
    fn = abort_fndecl;

  if (flag_vtable_thunks)
    {
      /* The first slot holds the offset.  */
      TREE_PURPOSE (virtuals) = offset;

      /* The next node holds the function.  */
      virtuals = TREE_CHAIN (virtuals);
      offset = integer_zero_node;
    }

  /* This slot holds the function to call.  */
  TREE_PURPOSE (virtuals) = offset;
  TREE_VALUE (virtuals) = fn;
}

/* Build a virtual function for type TYPE.
   If BINFO is non-NULL, build the vtable starting with the initial
   approximation that it is the same as the one which is the head of
   the association list.  */

static tree
build_vtable (binfo, type)
     tree binfo, type;
{
  tree name = get_vtable_name (type);
  tree virtuals, decl;

  if (binfo)
    {
      tree offset;

      virtuals = copy_list (BINFO_VIRTUALS (binfo));
      decl = build_lang_decl (VAR_DECL, name, 
			      TREE_TYPE (BINFO_VTABLE (binfo)));

      /* Now do rtti stuff.  */
      offset = get_derived_offset (TYPE_BINFO (type), NULL_TREE);
      offset = ssize_binop (MINUS_EXPR, integer_zero_node, offset);
      set_rtti_entry (virtuals, offset, type);
    }
  else
    {
      virtuals = NULL_TREE;
      decl = build_lang_decl (VAR_DECL, name, void_type_node);
    }

#ifdef GATHER_STATISTICS
  n_vtables += 1;
  n_vtable_elems += list_length (virtuals);
#endif

  /* Set TREE_PUBLIC and TREE_EXTERN as appropriate.  */
  import_export_vtable (decl, type, 0);

  decl = pushdecl_top_level (decl);
  SET_IDENTIFIER_GLOBAL_VALUE (name, decl);
  /* Initialize the association list for this type, based
     on our first approximation.  */
  TYPE_BINFO_VTABLE (type) = decl;
  TYPE_BINFO_VIRTUALS (type) = virtuals;

  DECL_ARTIFICIAL (decl) = 1;
  TREE_STATIC (decl) = 1;
#ifndef WRITABLE_VTABLES
  /* Make them READONLY by default. (mrs) */
  TREE_READONLY (decl) = 1;
#endif
  /* At one time the vtable info was grabbed 2 words at a time.  This
     fails on sparc unless you have 8-byte alignment.  (tiemann) */
  DECL_ALIGN (decl) = MAX (TYPE_ALIGN (double_type_node),
			   DECL_ALIGN (decl));

  DECL_VIRTUAL_P (decl) = 1;
  DECL_CONTEXT (decl) = type;

  binfo = TYPE_BINFO (type);
  SET_BINFO_NEW_VTABLE_MARKED (binfo);
  return decl;
}

/* Give TYPE a new virtual function table which is initialized
   with a skeleton-copy of its original initialization.  The only
   entry that changes is the `delta' entry, so we can really
   share a lot of structure.

   FOR_TYPE is the derived type which caused this table to
   be needed.

   BINFO is the type association which provided TYPE for FOR_TYPE.

   The order in which vtables are built (by calling this function) for
   an object must remain the same, otherwise a binary incompatibility
   can result.  */

static void
prepare_fresh_vtable (binfo, for_type)
     tree binfo, for_type;
{
  tree basetype;
  tree orig_decl = BINFO_VTABLE (binfo);
  tree name;
  tree new_decl;
  tree offset;
  tree path = binfo;
  char *buf, *buf2;
  char joiner = '_';
  int i;

#ifdef JOINER
  joiner = JOINER;
#endif

  basetype = TYPE_MAIN_VARIANT (BINFO_TYPE (binfo));

  buf2 = TYPE_ASSEMBLER_NAME_STRING (basetype);
  i = TYPE_ASSEMBLER_NAME_LENGTH (basetype) + 1;

  /* We know that the vtable that we are going to create doesn't exist
     yet in the global namespace, and when we finish, it will be
     pushed into the global namespace.  In complex MI hierarchies, we
     have to loop while the name we are thinking of adding is globally
     defined, adding more name components to the vtable name as we
     loop, until the name is unique.  This is because in complex MI
     cases, we might have the same base more than once.  This means
     that the order in which this function is called for vtables must
     remain the same, otherwise binary compatibility can be
     compromised.  */

  while (1)
    {
      char *buf1 = (char *) alloca (TYPE_ASSEMBLER_NAME_LENGTH (for_type)
				    + 1 + i);
      char *new_buf2;

      sprintf (buf1, "%s%c%s", TYPE_ASSEMBLER_NAME_STRING (for_type), joiner,
	       buf2);
      buf = (char *) alloca (strlen (VTABLE_NAME_PREFIX) + strlen (buf1) + 1);
      sprintf (buf, "%s%s", VTABLE_NAME_PREFIX, buf1);
      name = get_identifier (buf);

      /* If this name doesn't clash, then we can use it, otherwise
	 we add more to the name until it is unique.  */

      if (! IDENTIFIER_GLOBAL_VALUE (name))
	break;

      /* Set values for next loop through, if the name isn't unique.  */

      path = BINFO_INHERITANCE_CHAIN (path);

      /* We better not run out of stuff to make it unique.  */
      my_friendly_assert (path != NULL_TREE, 368);

      basetype = TYPE_MAIN_VARIANT (BINFO_TYPE (path));

      if (for_type == basetype)
	{
	  /* If we run out of basetypes in the path, we have already
	     found created a vtable with that name before, we now
	     resort to tacking on _%d to distinguish them.  */
	  int j = 2;
	  i = TYPE_ASSEMBLER_NAME_LENGTH (basetype) + 1 + i + 1 + 3;
	  buf1 = (char *) alloca (i);
	  do {
	    sprintf (buf1, "%s%c%s%c%d",
		     TYPE_ASSEMBLER_NAME_STRING (basetype), joiner,
		     buf2, joiner, j);
	    buf = (char *) alloca (strlen (VTABLE_NAME_PREFIX)
				   + strlen (buf1) + 1);
	    sprintf (buf, "%s%s", VTABLE_NAME_PREFIX, buf1);
	    name = get_identifier (buf);

	    /* If this name doesn't clash, then we can use it,
	       otherwise we add something different to the name until
	       it is unique.  */
	  } while (++j <= 999 && IDENTIFIER_GLOBAL_VALUE (name));

	  /* Hey, they really like MI don't they?  Increase the 3
             above to 6, and the 999 to 999999.  :-)  */
	  my_friendly_assert (j <= 999, 369);

	  break;
	}

      i = TYPE_ASSEMBLER_NAME_LENGTH (basetype) + 1 + i;
      new_buf2 = (char *) alloca (i);
      sprintf (new_buf2, "%s%c%s",
	       TYPE_ASSEMBLER_NAME_STRING (basetype), joiner, buf2);
      buf2 = new_buf2;
    }

  new_decl = build_lang_decl (VAR_DECL, name, TREE_TYPE (orig_decl));
  /* Remember which class this vtable is really for.  */
  DECL_CONTEXT (new_decl) = for_type;

  DECL_ARTIFICIAL (new_decl) = 1;
  TREE_STATIC (new_decl) = 1;
  BINFO_VTABLE (binfo) = pushdecl_top_level (new_decl);
  DECL_VIRTUAL_P (new_decl) = 1;
#ifndef WRITABLE_VTABLES
  /* Make them READONLY by default. (mrs) */
  TREE_READONLY (new_decl) = 1;
#endif
  DECL_ALIGN (new_decl) = DECL_ALIGN (orig_decl);

  /* Make fresh virtual list, so we can smash it later.  */
  BINFO_VIRTUALS (binfo) = copy_list (BINFO_VIRTUALS (binfo));

  if (TREE_VIA_VIRTUAL (binfo))
    {
      tree binfo1 = BINFO_FOR_VBASE (BINFO_TYPE (binfo), for_type);

      /* XXX - This should never happen, if it does, the caller should
	 ensure that the binfo is from for_type's binfos, not from any
	 base type's.  We can remove all this code after a while.  */
      if (binfo1 != binfo)
	warning ("internal inconsistency: binfo offset error for rtti");

      offset = BINFO_OFFSET (binfo1);
    }
  else
    offset = BINFO_OFFSET (binfo);

  set_rtti_entry (BINFO_VIRTUALS (binfo),
		  ssize_binop (MINUS_EXPR, integer_zero_node, offset),
		  for_type);

#ifdef GATHER_STATISTICS
  n_vtables += 1;
  n_vtable_elems += list_length (BINFO_VIRTUALS (binfo));
#endif

  /* Set TREE_PUBLIC and TREE_EXTERN as appropriate.  */
  import_export_vtable (new_decl, for_type, 0);

  if (TREE_VIA_VIRTUAL (binfo))
    my_friendly_assert (binfo == BINFO_FOR_VBASE (BINFO_TYPE (binfo),
						  current_class_type),
			170);
  SET_BINFO_NEW_VTABLE_MARKED (binfo);
}

#if 0
/* Access the virtual function table entry that logically
   contains BASE_FNDECL.  VIRTUALS is the virtual function table's
   initializer.  We can run off the end, when dealing with virtual
   destructors in MI situations, return NULL_TREE in that case.  */

static tree
get_vtable_entry (virtuals, base_fndecl)
     tree virtuals, base_fndecl;
{
  unsigned HOST_WIDE_INT n = (HOST_BITS_PER_WIDE_INT >= BITS_PER_WORD
	   ? (TREE_INT_CST_LOW (DECL_VINDEX (base_fndecl))
	      & (((unsigned HOST_WIDE_INT)1<<(BITS_PER_WORD-1))-1))
	   : TREE_INT_CST_LOW (DECL_VINDEX (base_fndecl)));

#ifdef GATHER_STATISTICS
  n_vtable_searches += n;
#endif

  while (n > 0 && virtuals)
    {
      --n;
      virtuals = TREE_CHAIN (virtuals);
    }
  return virtuals;
}
#endif

/* Change the offset for the FNDECL entry to NEW_OFFSET.  Also update
   DECL_VINDEX (FNDECL).  */

static void
modify_vtable_entry (old_entry_in_list, new_offset, fndecl)
     tree old_entry_in_list, new_offset, fndecl;
{
  tree base_fndecl = TREE_VALUE (old_entry_in_list);

  /* Update the entry.  */
  TREE_PURPOSE (old_entry_in_list) = new_offset;
  TREE_VALUE (old_entry_in_list) = fndecl;

  /* Now assign virtual dispatch information, if unset.  We can
     dispatch this, through any overridden base function.  */
  if (TREE_CODE (DECL_VINDEX (fndecl)) != INTEGER_CST)
    {
      DECL_VINDEX (fndecl) = DECL_VINDEX (base_fndecl);
      DECL_CONTEXT (fndecl) = DECL_CONTEXT (base_fndecl);
    }
}

/* Access the virtual function table entry N.  VIRTUALS is the virtual
   function table's initializer.  */

static tree
get_vtable_entry_n (virtuals, n)
     tree virtuals;
     unsigned HOST_WIDE_INT n;
{
  while (n > 0)
    {
      --n;
      virtuals = TREE_CHAIN (virtuals);
    }
  return virtuals;
}

/* Add a virtual function to all the appropriate vtables for the class
   T.  DECL_VINDEX(X) should be error_mark_node, if we want to
   allocate a new slot in our table.  If it is error_mark_node, we
   know that no other function from another vtable is overridden by X.
   HAS_VIRTUAL keeps track of how many virtuals there are in our main
   vtable for the type, and we build upon the PENDING_VIRTUALS list
   and return it.  */

static void
add_virtual_function (pv, phv, has_virtual, fndecl, t)
     tree *pv, *phv;
     int *has_virtual;
     tree fndecl;
     tree t; /* Structure type.  */
{
  tree pending_virtuals = *pv;
  tree pending_hard_virtuals = *phv;

#ifndef DUMB_USER
  if (current_class_type == 0)
    cp_warning ("internal problem, current_class_type is zero when adding `%D', please report",
		fndecl);
  if (current_class_type && t != current_class_type)
    cp_warning ("internal problem, current_class_type differs when adding `%D', please report",
		fndecl);
#endif

  /* If the virtual function is a redefinition of a prior one,
     figure out in which base class the new definition goes,
     and if necessary, make a fresh virtual function table
     to hold that entry.  */
  if (DECL_VINDEX (fndecl) == error_mark_node)
    {
      /* We remember that this was the base sub-object for rtti.  */
      CLASSTYPE_RTTI (t) = t;

      /* If we are using thunks, use two slots at the front, one
	 for the offset pointer, one for the tdesc pointer.
         For ARM-style vtables, use the same slot for both.  */
      if (*has_virtual == 0 && ! CLASSTYPE_COM_INTERFACE (t))
	{
	  if (flag_vtable_thunks)
	    *has_virtual = 2;
	  else
	    *has_virtual = 1;
	}

      /* Build a new INT_CST for this DECL_VINDEX.  */
      {
	static tree index_table[256];
	tree idx;
	/* We skip a slot for the offset/tdesc entry.  */
	int i = (*has_virtual)++;

	if (i >= 256 || index_table[i] == 0)
	  {
	    idx = build_int_2 (i, 0);
	    if (i < 256)
	      index_table[i] = idx;
	  }
	else
	  idx = index_table[i];

	/* Now assign virtual dispatch information.  */
	DECL_VINDEX (fndecl) = idx;
	DECL_CONTEXT (fndecl) = t;
      }
      /* Save the state we've computed on the PENDING_VIRTUALS list.  */
      pending_virtuals = tree_cons (integer_zero_node,
				    fndecl,
				    pending_virtuals);
    }
  /* Might already be INTEGER_CST if declared twice in class.  We will
     give error later or we've already given it.  */
  else if (TREE_CODE (DECL_VINDEX (fndecl)) != INTEGER_CST)
    {
      /* Need an entry in some other virtual function table.
         Deal with this after we have laid out our virtual base classes.  */
      pending_hard_virtuals = tree_cons (NULL_TREE, 
					 fndecl, 
					 pending_hard_virtuals);
    }
  *pv = pending_virtuals;
  *phv = pending_hard_virtuals;
}
\f
extern struct obstack *current_obstack;

/* Add method METHOD to class TYPE.

   If non-NULL, FIELDS is the entry in the METHOD_VEC vector entry of
   the class type where the method should be added.  */

void
add_method (type, fields, method)
     tree type, *fields, method;
{
  /* Setting the DECL_CONTEXT and DECL_CLASS_CONTEXT here is probably
     redundant.  */
  DECL_CONTEXT (method) = type;
  DECL_CLASS_CONTEXT (method) = type;
  
  if (fields && *fields)
    *fields = build_overload (method, *fields);
  else 
    {
      int len;
      int slot;
      tree method_vec;

      if (!CLASSTYPE_METHOD_VEC (type))
	/* Make a new method vector.  We start with 8 entries.  We must
	   allocate at least two (for constructors and destructors), and
	   we're going to end up with an assignment operator at some
	   point as well.  

	   We could use a TREE_LIST for now, and convert it to a
	   TREE_VEC in finish_struct, but we would probably waste more
	   memory making the links in the list than we would by
	   over-allocating the size of the vector here.  Furthermore,
	   we would complicate all the code that expects this to be a
	   vector.  */
	CLASSTYPE_METHOD_VEC (type) = make_tree_vec (8);

      method_vec = CLASSTYPE_METHOD_VEC (type);
      len = TREE_VEC_LENGTH (method_vec);

      if (DECL_NAME (method) == constructor_name (type))
	/* A new constructor or destructor.  Constructors go in 
	   slot 0; destructors go in slot 1.  */
	slot = DESTRUCTOR_NAME_P (DECL_ASSEMBLER_NAME (method)) ? 1 : 0;
      else
	{
	  /* See if we already have an entry with this name.  */
	  for (slot = 2; slot < len; ++slot)
	    if (!TREE_VEC_ELT (method_vec, slot)
		|| (DECL_NAME (OVL_CURRENT (TREE_VEC_ELT (method_vec, 
							  slot))) 
		    == DECL_NAME (method)))
	      break;
		
	  if (slot == len)
	    {
	      /* We need a bigger method vector.  */
	      tree new_vec = make_tree_vec (2 * len);
	      bcopy ((PTR) &TREE_VEC_ELT (method_vec, 0),
		     (PTR) &TREE_VEC_ELT (new_vec, 0),
		     len * sizeof (tree));
	      len = 2 * len;
	      method_vec = CLASSTYPE_METHOD_VEC (type) = new_vec;
	    }

	  if (DECL_CONV_FN_P (method) && !TREE_VEC_ELT (method_vec, slot))
	    {
	      /* Type conversion operators have to come before
		 ordinary methods; add_conversions depends on this to
		 speed up looking for conversion operators.  So, if
		 necessary, we slide some of the vector elements up.
		 In theory, this makes this algorithm O(N^2) but we
		 don't expect many conversion operators.  */
	      for (slot = 2; slot < len; ++slot)
		{
		  tree fn = TREE_VEC_ELT (method_vec, slot);
  
		  if (!fn)
		    /* There are no more entries in the vector, so we
		       can insert the new conversion operator here.  */
		    break;
  		  
		  if (!DECL_CONV_FN_P (OVL_CURRENT (fn)))
		    /* We can insert the new function right at the
		       SLOTth position.  */
		    break;
		}
  
	      if (!TREE_VEC_ELT (method_vec, slot))
		/* There is nothing in the Ith slot, so we can avoid
		   moving anything.  */
		; 
	      else
		{
		  /* We know the last slot in the vector is empty
		     because we know that at this point there's room
		     for a new function.  */
		  bcopy ((PTR) &TREE_VEC_ELT (method_vec, slot),
			 (PTR) &TREE_VEC_ELT (method_vec, slot + 1),
			 (len - slot - 1) * sizeof (tree));
		  TREE_VEC_ELT (method_vec, slot) = NULL_TREE;
		}
	    }
	}
      
      if (template_class_depth (type))
	/* TYPE is a template class.  Don't issue any errors now; wait
	   until instantiation time to complain.  */
	  ;
      else
	{
	  tree fns;

	  /* Check to see if we've already got this method.  */
	  for (fns = TREE_VEC_ELT (method_vec, slot);
	       fns;
	       fns = OVL_NEXT (fns))
	    {
	      tree fn = OVL_CURRENT (fns);
		 
	      if (TREE_CODE (fn) != TREE_CODE (method))
		continue;

	      if (TREE_CODE (method) != TEMPLATE_DECL)
		{
		  /* [over.load] Member function declarations with the
		     same name and the same parameter types cannot be
		     overloaded if any of them is a static member
		     function declaration.  */
		  if (DECL_STATIC_FUNCTION_P (fn)
		      != DECL_STATIC_FUNCTION_P (method))
		    {
		      tree parms1 = TYPE_ARG_TYPES (TREE_TYPE (fn));
		      tree parms2 = TYPE_ARG_TYPES (TREE_TYPE (method));

		      if (! DECL_STATIC_FUNCTION_P (fn))
			parms1 = TREE_CHAIN (parms1);
		      else
			parms2 = TREE_CHAIN (parms2);

		      if (compparms (parms1, parms2))
			cp_error ("`%#D' and `%#D' cannot be overloaded",
				  fn, method);
		    }

		  /* Since this is an ordinary function in a
		     non-template class, it's mangled name can be used
		     as a unique identifier.  This technique is only
		     an optimization; we would get the same results if
		     we just used decls_match here.  */
		  if (DECL_ASSEMBLER_NAME (fn) 
		      != DECL_ASSEMBLER_NAME (method))
		    continue;
		}
	      else if (!decls_match (fn, method))
		continue;

	      /* There has already been a declaration of this method
		 or member template.  */
	      cp_error_at ("`%D' has already been declared in `%T'", 
			   method, type);

	      /* We don't call duplicate_decls here to merge the
		 declarations because that will confuse things if the
		 methods have inline definitions.  In particular, we
		 will crash while processing the definitions.  */
	      return;
	    }
	}

      /* Actually insert the new method.  */
      TREE_VEC_ELT (method_vec, slot) 
	= build_overload (method, TREE_VEC_ELT (method_vec, slot));

      /* Add the new binding.  */ 
      if (!DECL_CONSTRUCTOR_P (method)
	  && !DECL_DESTRUCTOR_P (method))
	push_class_level_binding (DECL_NAME (method),
				  TREE_VEC_ELT (method_vec, slot));
    }
}

/* Subroutines of finish_struct.  */

/* Look through the list of fields for this struct, deleting
   duplicates as we go.  This must be recursive to handle
   anonymous unions.

   FIELD is the field which may not appear anywhere in FIELDS.
   FIELD_PTR, if non-null, is the starting point at which
   chained deletions may take place.
   The value returned is the first acceptable entry found
   in FIELDS.

   Note that anonymous fields which are not of UNION_TYPE are
   not duplicates, they are just anonymous fields.  This happens
   when we have unnamed bitfields, for example.  */

static tree
delete_duplicate_fields_1 (field, fields)
     tree field, fields;
{
  tree x;
  tree prev = 0;
  if (DECL_NAME (field) == 0)
    {
      if (! ANON_AGGR_TYPE_P (TREE_TYPE (field)))
	return fields;

      for (x = TYPE_FIELDS (TREE_TYPE (field)); x; x = TREE_CHAIN (x))
	fields = delete_duplicate_fields_1 (x, fields);
      return fields;
    }
  else
    {
      for (x = fields; x; prev = x, x = TREE_CHAIN (x))
	{
	  if (DECL_NAME (x) == 0)
	    {
	      if (! ANON_AGGR_TYPE_P (TREE_TYPE (x)))
		continue;
	      TYPE_FIELDS (TREE_TYPE (x))
		= delete_duplicate_fields_1 (field, TYPE_FIELDS (TREE_TYPE (x)));
	      if (TYPE_FIELDS (TREE_TYPE (x)) == 0)
		{
		  if (prev == 0)
		    fields = TREE_CHAIN (fields);
		  else
		    TREE_CHAIN (prev) = TREE_CHAIN (x);
		}
	    }
	  else if (TREE_CODE (field) == USING_DECL)
	    /* A using declaration may is allowed to appear more than
	       once.  We'll prune these from the field list later, and
	       handle_using_decl will complain about invalid multiple
	       uses.  */
	    ;
	  else if (DECL_NAME (field) == DECL_NAME (x))
	    {
	      if (TREE_CODE (field) == CONST_DECL
		  && TREE_CODE (x) == CONST_DECL)
		cp_error_at ("duplicate enum value `%D'", x);
	      else if (TREE_CODE (field) == CONST_DECL
		       || TREE_CODE (x) == CONST_DECL)
		cp_error_at ("duplicate field `%D' (as enum and non-enum)",
			     x);
	      else if (DECL_DECLARES_TYPE_P (field)
		       && DECL_DECLARES_TYPE_P (x))
		{
		  if (same_type_p (TREE_TYPE (field), TREE_TYPE (x)))
		    continue;
		  cp_error_at ("duplicate nested type `%D'", x);
		}
	      else if (DECL_DECLARES_TYPE_P (field)
		       || DECL_DECLARES_TYPE_P (x))
		{
		  /* Hide tag decls.  */
		  if ((TREE_CODE (field) == TYPE_DECL
		       && DECL_ARTIFICIAL (field))
		      || (TREE_CODE (x) == TYPE_DECL
			  && DECL_ARTIFICIAL (x)))
		    continue;
		  cp_error_at ("duplicate field `%D' (as type and non-type)",
			       x);
		}
	      else
		cp_error_at ("duplicate member `%D'", x);
	      if (prev == 0)
		fields = TREE_CHAIN (fields);
	      else
		TREE_CHAIN (prev) = TREE_CHAIN (x);
	    }
	}
    }
  return fields;
}

static void
delete_duplicate_fields (fields)
     tree fields;
{
  tree x;
  for (x = fields; x && TREE_CHAIN (x); x = TREE_CHAIN (x))
    TREE_CHAIN (x) = delete_duplicate_fields_1 (x, TREE_CHAIN (x));
}

/* Change the access of FDECL to ACCESS in T.  The access to FDECL is
   along the path given by BINFO.  Return 1 if change was legit,
   otherwise return 0.  */

static int
alter_access (t, binfo, fdecl, access)
     tree t;
     tree binfo;
     tree fdecl;
     tree access;
{
  tree elem = purpose_member (t, DECL_ACCESS (fdecl));
  if (elem)
    {
      if (TREE_VALUE (elem) != access)
	{
	  if (TREE_CODE (TREE_TYPE (fdecl)) == FUNCTION_DECL)
	    cp_error_at ("conflicting access specifications for method `%D', ignored", TREE_TYPE (fdecl));
	  else
	    error ("conflicting access specifications for field `%s', ignored",
		   IDENTIFIER_POINTER (DECL_NAME (fdecl)));
	}
      else
	{
	  /* They're changing the access to the same thing they changed
	     it to before.  That's OK.  */
	  ;
	}
    }
  else
    {
      enforce_access (binfo, fdecl);
      DECL_ACCESS (fdecl) = tree_cons (t, access, DECL_ACCESS (fdecl));
      return 1;
    }
  return 0;
}

/* Process the USING_DECL, which is a member of T.  */

static void
handle_using_decl (using_decl, t)
     tree using_decl;
     tree t;
{
  tree ctype = DECL_INITIAL (using_decl);
  tree name = DECL_NAME (using_decl);
  tree access
    = TREE_PRIVATE (using_decl) ? access_private_node
    : TREE_PROTECTED (using_decl) ? access_protected_node
    : access_public_node;
  tree fdecl, binfo;
  tree flist = NULL_TREE;
  tree fields = TYPE_FIELDS (t);
  tree method_vec = CLASSTYPE_METHOD_VEC (t);
  tree tmp;
  int i;
  int n_methods;

  binfo = binfo_or_else (ctype, t);
  if (! binfo)
    return;
  
  if (name == constructor_name (ctype)
      || name == constructor_name_full (ctype))
    {
      cp_error_at ("using-declaration for constructor", using_decl);
      return;
    }

  fdecl = lookup_member (binfo, name, 0, 0);
  
  if (!fdecl)
    {
      cp_error_at ("no members matching `%D' in `%#T'", using_decl, ctype);
      return;
    }

  /* Functions are represented as TREE_LIST, with the purpose
     being the type and the value the functions. Other members
     come as themselves. */
  if (TREE_CODE (fdecl) == TREE_LIST)
    /* Ignore base type this came from. */
    fdecl = TREE_VALUE (fdecl);

  if (TREE_CODE (fdecl) == OVERLOAD)
    {
      /* We later iterate over all functions. */
      flist = fdecl;
      fdecl = OVL_FUNCTION (flist);
    }
  
  name = DECL_NAME (fdecl);
  n_methods = method_vec ? TREE_VEC_LENGTH (method_vec) : 0;
  for (i = 2; i < n_methods && TREE_VEC_ELT (method_vec, i); i++)
    if (DECL_NAME (OVL_CURRENT (TREE_VEC_ELT (method_vec, i)))
	== name)
      {
	cp_error ("cannot adjust access to `%#D' in `%#T'", fdecl, t);
	cp_error_at ("  because of local method `%#D' with same name",
		     OVL_CURRENT (TREE_VEC_ELT (method_vec, i)));
	return;
      }

  if (! DECL_LANG_SPECIFIC (fdecl))
    /* We don't currently handle DECL_ACCESS for TYPE_DECLs; just return.  */
    return;
  
  for (tmp = fields; tmp; tmp = TREE_CHAIN (tmp))
    if (DECL_NAME (tmp) == name)
      {
	cp_error ("cannot adjust access to `%#D' in `%#T'", fdecl, t);
	cp_error_at ("  because of local field `%#D' with same name", tmp);
	return;
      }
  
  /* Make type T see field decl FDECL with access ACCESS.*/
  if (flist)
    {
      while (flist)
	{
	  if (alter_access (t, binfo, OVL_FUNCTION (flist), 
			    access) == 0)
	    return;
	  flist = OVL_CHAIN (flist);
	}
    }
  else
    alter_access (t, binfo, fdecl, access);
}
\f
struct base_info
{
  int has_virtual;
  int max_has_virtual;
  tree vfield;
  tree vfields;
  tree rtti;
};

/* Run through the base clases of T, updating
   CANT_HAVE_DEFAULT_CTOR_P, CANT_HAVE_CONST_CTOR_P, and
   NO_CONST_ASN_REF_P.  Also set flag bits in T based on properties of
   the bases.  */

static void
check_bases (t, cant_have_default_ctor_p, cant_have_const_ctor_p,
	     no_const_asn_ref_p)
     tree t;
     int *cant_have_default_ctor_p;
     int *cant_have_const_ctor_p;
     int *no_const_asn_ref_p;
{
  int n_baseclasses;
  int i;
  int seen_nearly_empty_base_p;
  tree binfos;

  binfos = TYPE_BINFO_BASETYPES (t);
  n_baseclasses = CLASSTYPE_N_BASECLASSES (t);
  seen_nearly_empty_base_p = 0;

  /* An aggregate cannot have baseclasses.  */
  CLASSTYPE_NON_AGGREGATE (t) |= (n_baseclasses != 0);

  for (i = 0; i < n_baseclasses; ++i) 
    {
      tree base_binfo;
      tree basetype;

      /* Figure out what base we're looking at.  */
      base_binfo = TREE_VEC_ELT (binfos, i);
      basetype = TREE_TYPE (base_binfo);

      /* If the type of basetype is incomplete, then we already
	 complained about that fact (and we should have fixed it up as
	 well).  */
      if (TYPE_SIZE (basetype) == 0)
	{
	  int j;
	  /* The base type is of incomplete type.  It is
	     probably best to pretend that it does not
	     exist.  */
	  if (i == n_baseclasses-1)
	    TREE_VEC_ELT (binfos, i) = NULL_TREE;
	  TREE_VEC_LENGTH (binfos) -= 1;
	  n_baseclasses -= 1;
	  for (j = i; j+1 < n_baseclasses; j++)
	    TREE_VEC_ELT (binfos, j) = TREE_VEC_ELT (binfos, j+1);
	  continue;
	}

      /* Effective C++ rule 14.  We only need to check TYPE_POLYMORPHIC_P
	 here because the case of virtual functions but non-virtual
	 dtor is handled in finish_struct_1.  */
      if (warn_ecpp && ! TYPE_POLYMORPHIC_P (basetype)
	  && TYPE_HAS_DESTRUCTOR (basetype))
	cp_warning ("base class `%#T' has a non-virtual destructor",
		    basetype);

      /* If the base class doesn't have copy constructors or
	 assignment operators that take const references, then the
	 derived class cannot have such a member automatically
	 generated.  */
      if (! TYPE_HAS_CONST_INIT_REF (basetype))
	*cant_have_const_ctor_p = 1;
      if (TYPE_HAS_ASSIGN_REF (basetype)
	  && !TYPE_HAS_CONST_ASSIGN_REF (basetype))
	*no_const_asn_ref_p = 1;
      /* Similarly, if the base class doesn't have a default
	 constructor, then the derived class won't have an
	 automatically generated default constructor.  */
      if (TYPE_HAS_CONSTRUCTOR (basetype)
	  && ! TYPE_HAS_DEFAULT_CONSTRUCTOR (basetype))
	{
	  *cant_have_default_ctor_p = 1;
	  if (! TYPE_HAS_CONSTRUCTOR (t))
	    {
	      cp_pedwarn ("base `%T' with only non-default constructor",
			  basetype);
	      cp_pedwarn ("in class without a constructor");
	    }
	}

      /* If the base class is not empty or nearly empty, then this
	 class cannot be nearly empty.  */
      if (!CLASSTYPE_NEARLY_EMPTY_P (basetype) && !is_empty_class (basetype))
	CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
      /* And if there is more than one nearly empty base, then the
	 derived class is not nearly empty either.  */
      else if (CLASSTYPE_NEARLY_EMPTY_P (basetype) 
	       && seen_nearly_empty_base_p)
	CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
      /* If this is the first nearly empty base class, then remember
	 that we saw it.  */
      else if (CLASSTYPE_NEARLY_EMPTY_P (basetype))
	seen_nearly_empty_base_p = 1;

      /* A lot of properties from the bases also apply to the derived
	 class.  */
      TYPE_NEEDS_CONSTRUCTING (t) |= TYPE_NEEDS_CONSTRUCTING (basetype);
      TYPE_NEEDS_DESTRUCTOR (t) |= TYPE_NEEDS_DESTRUCTOR (basetype);
      TYPE_HAS_COMPLEX_ASSIGN_REF (t) 
	|= TYPE_HAS_COMPLEX_ASSIGN_REF (basetype);
      TYPE_HAS_COMPLEX_INIT_REF (t) |= TYPE_HAS_COMPLEX_INIT_REF (basetype);
      TYPE_OVERLOADS_CALL_EXPR (t) |= TYPE_OVERLOADS_CALL_EXPR (basetype);
      TYPE_OVERLOADS_ARRAY_REF (t) |= TYPE_OVERLOADS_ARRAY_REF (basetype);
      TYPE_OVERLOADS_ARROW (t) |= TYPE_OVERLOADS_ARROW (basetype);
      TYPE_POLYMORPHIC_P (t) |= TYPE_POLYMORPHIC_P (basetype);

      /* Derived classes can implicitly become COMified if their bases
	 are COM.  */
      if (CLASSTYPE_COM_INTERFACE (basetype))
	CLASSTYPE_COM_INTERFACE (t) = 1;
      else if (i == 0 && CLASSTYPE_COM_INTERFACE (t))
	{
	  cp_error 
	    ("COM interface type `%T' with non-COM leftmost base class `%T'",
	     t, basetype);
	  CLASSTYPE_COM_INTERFACE (t) = 0;
	}
    }
}

/* Record information about type T derived from its base classes.
   Store most of that information in T itself, and place the
   remaining information in the struct BASE_INFO.

   Propagate basetype offsets throughout the lattice.  Note that the
   lattice topped by T is really a pair: it's a DAG that gives the
   structure of the derivation hierarchy, and it's a list of the
   virtual baseclasses that appear anywhere in the DAG.  When a vbase
   type appears in the DAG, it's offset is 0, and it's children start
   their offsets from that point.  When a vbase type appears in the list,
   its offset is the offset it has in the hierarchy, and its children's
   offsets include that offset in theirs.

   Returns the index of the first base class to have virtual functions,
   or -1 if no such base class.  */

static int
finish_base_struct (t, b)
     tree t;
     struct base_info *b;
{
  tree binfos = TYPE_BINFO_BASETYPES (t);
  int i, n_baseclasses = CLASSTYPE_N_BASECLASSES (t);
  int first_vfn_base_index = -1;
  bzero ((char *) b, sizeof (struct base_info));

  for (i = 0; i < n_baseclasses; i++)
    {
      tree base_binfo = TREE_VEC_ELT (binfos, i);
      tree basetype = BINFO_TYPE (base_binfo);

      if (TYPE_POLYMORPHIC_P (basetype))
	{
	  /* Ensure that this is set from at least a virtual base
             class.  */
	  if (b->rtti == NULL_TREE)
	    b->rtti = CLASSTYPE_RTTI (basetype);

	  /* Don't borrow virtuals from virtual baseclasses.  */
	  if (TREE_VIA_VIRTUAL (base_binfo))
	    continue;

	  if (first_vfn_base_index < 0)
	    {
	      tree vfields;
	      first_vfn_base_index = i;

	      /* Update these two, now that we know what vtable we are
		 going to extend.  This is so that we can add virtual
		 functions, and override them properly.  */
	      TYPE_BINFO_VTABLE (t) = TYPE_BINFO_VTABLE (basetype);
	      TYPE_BINFO_VIRTUALS (t) = TYPE_BINFO_VIRTUALS (basetype);
	      b->has_virtual = CLASSTYPE_VSIZE (basetype);
	      b->vfield = TYPE_VFIELD (basetype);
	      b->vfields = copy_list (CLASSTYPE_VFIELDS (basetype));
	      vfields = b->vfields;
	      while (vfields)
		{
		  if (VF_BINFO_VALUE (vfields) == NULL_TREE
		      || ! TREE_VIA_VIRTUAL (VF_BINFO_VALUE (vfields)))
		    {
		      tree value = VF_BASETYPE_VALUE (vfields);
		      if (DECL_NAME (TYPE_VFIELD (value))
			  == DECL_NAME (TYPE_VFIELD (basetype)))
			VF_NORMAL_VALUE (b->vfields) = basetype;
		      else
			VF_NORMAL_VALUE (b->vfields) = VF_NORMAL_VALUE (vfields);
		    }
		  vfields = TREE_CHAIN (vfields);
		}
	      TYPE_VFIELD (t) = b->vfield;
	    }
	  else
	    {
	      /* Only add unique vfields, and flatten them out as we go.  */
	      tree vfields = CLASSTYPE_VFIELDS (basetype);
	      while (vfields)
		{
		  if (VF_BINFO_VALUE (vfields) == NULL_TREE
		      || ! TREE_VIA_VIRTUAL (VF_BINFO_VALUE (vfields)))
		    {
		      tree value = VF_BASETYPE_VALUE (vfields);
		      b->vfields = tree_cons (base_binfo, value, b->vfields);
		      if (DECL_NAME (TYPE_VFIELD (value))
			  == DECL_NAME (TYPE_VFIELD (basetype)))
			VF_NORMAL_VALUE (b->vfields) = basetype;
		      else
			VF_NORMAL_VALUE (b->vfields) = VF_NORMAL_VALUE (vfields);
		    }
		  vfields = TREE_CHAIN (vfields);
		}

	      if (b->has_virtual == 0)
		{
		  first_vfn_base_index = i;

		  /* Update these two, now that we know what vtable we are
		     going to extend.  This is so that we can add virtual
		     functions, and override them properly.  */
		  TYPE_BINFO_VTABLE (t) = TYPE_BINFO_VTABLE (basetype);
		  TYPE_BINFO_VIRTUALS (t) = TYPE_BINFO_VIRTUALS (basetype);
		  b->has_virtual = CLASSTYPE_VSIZE (basetype);
		  b->vfield = TYPE_VFIELD (basetype);
		  TYPE_VFIELD (t) = b->vfield;
		  /* When we install the first one, set the VF_NORMAL_VALUE
		     to be the current class, as this it is the most derived
		     class.  Hopefully, this is not set to something else
		     later.  (mrs) */
		  vfields = b->vfields;
		  while (vfields)
		    {
		      if (DECL_NAME (TYPE_VFIELD (t))
			  == DECL_NAME (TYPE_VFIELD (basetype)))
			{
			  VF_NORMAL_VALUE (vfields) = t;
			  /* There should only be one of them!  And it should
			     always be found, if we get into here.  (mrs)  */
			  break;
			}
		      vfields = TREE_CHAIN (vfields);
		    }
		}
	    }
	}
    }

  {
    tree vfields;
    /* Find the base class with the largest number of virtual functions.  */
    for (vfields = b->vfields; vfields; vfields = TREE_CHAIN (vfields))
      {
	if (CLASSTYPE_VSIZE (VF_BASETYPE_VALUE (vfields)) > b->max_has_virtual)
	  b->max_has_virtual = CLASSTYPE_VSIZE (VF_BASETYPE_VALUE (vfields));
	if (VF_DERIVED_VALUE (vfields)
	    && CLASSTYPE_VSIZE (VF_DERIVED_VALUE (vfields)) > b->max_has_virtual)
	  b->max_has_virtual = CLASSTYPE_VSIZE (VF_DERIVED_VALUE (vfields));
      }
  }

  if (b->vfield == 0)
    /* If all virtual functions come only from virtual baseclasses.  */
    return -1;

  /* Update the rtti base if we have a non-virtual base class version
     of it.  */
  b->rtti = CLASSTYPE_RTTI (BINFO_TYPE (TREE_VEC_ELT (binfos, first_vfn_base_index)));

  return first_vfn_base_index;
}
\f
/* Set memoizing fields and bits of T (and its variants) for later use.
   MAX_HAS_VIRTUAL is the largest size of any T's virtual function tables.  */

static void
finish_struct_bits (t, max_has_virtual)
     tree t;
     int max_has_virtual;
{
  int i, n_baseclasses = CLASSTYPE_N_BASECLASSES (t);

  /* Fix up variants (if any).  */
  tree variants = TYPE_NEXT_VARIANT (t);
  while (variants)
    {
      /* These fields are in the _TYPE part of the node, not in
	 the TYPE_LANG_SPECIFIC component, so they are not shared.  */
      TYPE_HAS_CONSTRUCTOR (variants) = TYPE_HAS_CONSTRUCTOR (t);
      TYPE_HAS_DESTRUCTOR (variants) = TYPE_HAS_DESTRUCTOR (t);
      TYPE_NEEDS_CONSTRUCTING (variants) = TYPE_NEEDS_CONSTRUCTING (t);
      TYPE_NEEDS_DESTRUCTOR (variants) = TYPE_NEEDS_DESTRUCTOR (t);

      TYPE_BASE_CONVS_MAY_REQUIRE_CODE_P (variants) 
	= TYPE_BASE_CONVS_MAY_REQUIRE_CODE_P (t);
      TYPE_POLYMORPHIC_P (variants) = TYPE_POLYMORPHIC_P (t);
      TYPE_USES_VIRTUAL_BASECLASSES (variants) = TYPE_USES_VIRTUAL_BASECLASSES (t);
      /* Copy whatever these are holding today.  */
      TYPE_MIN_VALUE (variants) = TYPE_MIN_VALUE (t);
      TYPE_MAX_VALUE (variants) = TYPE_MAX_VALUE (t);
      TYPE_FIELDS (variants) = TYPE_FIELDS (t);
      TYPE_SIZE (variants) = TYPE_SIZE (t);
      TYPE_SIZE_UNIT (variants) = TYPE_SIZE_UNIT (t);
      variants = TYPE_NEXT_VARIANT (variants);
    }

  if (n_baseclasses && max_has_virtual)
    /* For a class w/o baseclasses, `finish_struct' has set
       CLASS_TYPE_ABSTRACT_VIRTUALS correctly (by
       definition). Similarly for a class whose base classes do not
       have vtables. When neither of these is true, we might have
       removed abstract virtuals (by providing a definition), added
       some (by declaring new ones), or redeclared ones from a base
       class. We need to recalculate what's really an abstract virtual
       at this point (by looking in the vtables).  */
      get_pure_virtuals (t);

  if (n_baseclasses)
    {
      /* Notice whether this class has type conversion functions defined.  */
      tree binfo = TYPE_BINFO (t);
      tree binfos = BINFO_BASETYPES (binfo);
      tree basetype;

      for (i = n_baseclasses-1; i >= 0; i--)
	{
	  basetype = BINFO_TYPE (TREE_VEC_ELT (binfos, i));

	  TYPE_HAS_CONVERSION (t) |= TYPE_HAS_CONVERSION (basetype);
	}
    }

  /* If this type has a copy constructor, force its mode to be BLKmode, and
     force its TREE_ADDRESSABLE bit to be nonzero.  This will cause it to
     be passed by invisible reference and prevent it from being returned in
     a register.

     Also do this if the class has BLKmode but can still be returned in
     registers, since function_cannot_inline_p won't let us inline
     functions returning such a type.  This affects the HP-PA.  */
  if (! TYPE_HAS_TRIVIAL_INIT_REF (t)
      || (TYPE_MODE (t) == BLKmode && ! aggregate_value_p (t)
	  && CLASSTYPE_NON_AGGREGATE (t)))
    {
      tree variants;
      DECL_MODE (TYPE_MAIN_DECL (t)) = BLKmode;
      for (variants = t; variants; variants = TYPE_NEXT_VARIANT (variants))
	{
	  TYPE_MODE (variants) = BLKmode;
	  TREE_ADDRESSABLE (variants) = 1;
	}
    }
}

/* Issue warnings about T having private constructors, but no friends,
   and so forth.  

   HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
   static members.  HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
   non-private static member functions.  */

static void
maybe_warn_about_overly_private_class (t)
     tree t;
{
  int has_member_fn = 0;
  int has_nonprivate_method = 0;
  tree fn;

  if (!warn_ctor_dtor_privacy
      /* If the class has friends, those entities might create and
	 access instances, so we should not warn.  */
      || (CLASSTYPE_FRIEND_CLASSES (t)
	  || DECL_FRIENDLIST (TYPE_MAIN_DECL (t)))
      /* We will have warned when the template was declared; there's
	 no need to warn on every instantiation.  */
      || CLASSTYPE_TEMPLATE_INSTANTIATION (t))
    /* There's no reason to even consider warning about this 
       class.  */
    return;
    
  /* We only issue one warning, if more than one applies, because
     otherwise, on code like:

     class A {
       // Oops - forgot `public:'
       A();
       A(const A&);
       ~A();
     };

     we warn several times about essentially the same problem.  */

  /* Check to see if all (non-constructor, non-destructor) member
     functions are private.  (Since there are no friends or
     non-private statics, we can't ever call any of the private member
     functions.)  */
  for (fn = TYPE_METHODS (t); fn; fn = TREE_CHAIN (fn))
    /* We're not interested in compiler-generated methods; they don't
       provide any way to call private members.  */
    if (!DECL_ARTIFICIAL (fn)) 
      {
	if (!TREE_PRIVATE (fn))
	  {
	    if (DECL_STATIC_FUNCTION_P (fn)) 
	      /* A non-private static member function is just like a
		 friend; it can create and invoke private member
		 functions, and be accessed without a class
		 instance.  */
	      return;
		
	    has_nonprivate_method = 1;
	    break;
	  }
	else if (!DECL_CONSTRUCTOR_P (fn) && !DECL_DESTRUCTOR_P (fn))
	  has_member_fn = 1;
      } 

  if (!has_nonprivate_method && has_member_fn) 
    {
      /* There are no non-private methods, and there's at least one
	 private member function that isn't a constructor or
	 destructor.  (If all the private members are
	 constructors/destructors we want to use the code below that
	 issues error messages specifically referring to
	 constructors/destructors.)  */
      int i;
      tree binfos = BINFO_BASETYPES (TYPE_BINFO (t));
      for (i = 0; i < CLASSTYPE_N_BASECLASSES (t); i++)
	if (TREE_VIA_PUBLIC (TREE_VEC_ELT (binfos, i))
	    || TREE_VIA_PROTECTED (TREE_VEC_ELT (binfos, i)))
	  {
	    has_nonprivate_method = 1;
	    break;
	  }
      if (!has_nonprivate_method) 
	{
	  cp_warning ("all member functions in class `%T' are private", t);
	  return;
	}
    }

  /* Even if some of the member functions are non-private, the class
     won't be useful for much if all the constructors or destructors
     are private: such an object can never be created or destroyed.  */
  if (TYPE_HAS_DESTRUCTOR (t))
    {
      tree dtor = TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (t), 1);

      if (TREE_PRIVATE (dtor))
	{
	  cp_warning ("`%#T' only defines a private destructor and has no friends",
		      t);
	  return;
	}
    }

  if (TYPE_HAS_CONSTRUCTOR (t))
    {
      int nonprivate_ctor = 0;
	  
      /* If a non-template class does not define a copy
	 constructor, one is defined for it, enabling it to avoid
	 this warning.  For a template class, this does not
	 happen, and so we would normally get a warning on:

	   template <class T> class C { private: C(); };  
	  
	 To avoid this asymmetry, we check TYPE_HAS_INIT_REF.  All
	 complete non-template or fully instantiated classes have this
	 flag set.  */
      if (!TYPE_HAS_INIT_REF (t))
	nonprivate_ctor = 1;
      else 
	for (fn = TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (t), 0);
	     fn;
	     fn = OVL_NEXT (fn)) 
	  {
	    tree ctor = OVL_CURRENT (fn);
	    /* Ideally, we wouldn't count copy constructors (or, in
	       fact, any constructor that takes an argument of the
	       class type as a parameter) because such things cannot
	       be used to construct an instance of the class unless
	       you already have one.  But, for now at least, we're
	       more generous.  */
	    if (! TREE_PRIVATE (ctor))
	      {
		nonprivate_ctor = 1;
		break;
	      }
	  }

      if (nonprivate_ctor == 0)
	{
	  cp_warning ("`%#T' only defines private constructors and has no friends",
		      t);
	  return;
	}
    }
}

/* Function to help qsort sort FIELD_DECLs by name order.  */

static int
field_decl_cmp (x, y)
     const tree *x, *y;
{
  if (DECL_NAME (*x) == DECL_NAME (*y))
    return 0;
  if (DECL_NAME (*x) == NULL_TREE)
    return -1;
  if (DECL_NAME (*y) == NULL_TREE)
    return 1;
  if (DECL_NAME (*x) < DECL_NAME (*y))
    return -1;
  return 1;
}

/* Comparison function to compare two TYPE_METHOD_VEC entries by name.  */

static int
method_name_cmp (m1, m2)
     const tree *m1, *m2;
{
  if (*m1 == NULL_TREE && *m2 == NULL_TREE)
    return 0;
  if (*m1 == NULL_TREE)
    return -1;
  if (*m2 == NULL_TREE)
    return 1;
  if (DECL_NAME (OVL_CURRENT (*m1)) < DECL_NAME (OVL_CURRENT (*m2)))
    return -1;
  return 1;
}

/* Warn about duplicate methods in fn_fields.  Also compact method
   lists so that lookup can be made faster.

   Data Structure: List of method lists.  The outer list is a
   TREE_LIST, whose TREE_PURPOSE field is the field name and the
   TREE_VALUE is the DECL_CHAIN of the FUNCTION_DECLs.  TREE_CHAIN
   links the entire list of methods for TYPE_METHODS.  Friends are
   chained in the same way as member functions (? TREE_CHAIN or
   DECL_CHAIN), but they live in the TREE_TYPE field of the outer
   list.  That allows them to be quickly deleted, and requires no
   extra storage.

   If there are any constructors/destructors, they are moved to the
   front of the list.  This makes pushclass more efficient.

   @@ The above comment is obsolete.  It mostly describes what add_method
   @@ and add_implicitly_declared_members do.

   Sort methods that are not special (i.e., constructors, destructors, and
   type conversion operators) so that we can find them faster in search.  */

static void
finish_struct_methods (t)
     tree t;
{
  tree fn_fields;
  tree method_vec;
  tree ctor_name = constructor_name (t);
  int slot, len;

  if (!TYPE_METHODS (t))
    {
      /* Clear these for safety; perhaps some parsing error could set
	 these incorrectly.  */
      TYPE_HAS_CONSTRUCTOR (t) = 0;
      TYPE_HAS_DESTRUCTOR (t) = 0;
      CLASSTYPE_METHOD_VEC (t) = NULL_TREE;
      return;
    }

  method_vec = CLASSTYPE_METHOD_VEC (t);
  my_friendly_assert (method_vec != NULL_TREE, 19991215);
  len = TREE_VEC_LENGTH (method_vec);

  /* First fill in entry 0 with the constructors, entry 1 with destructors,
     and the next few with type conversion operators (if any).  */
  for (fn_fields = TYPE_METHODS (t); fn_fields; 
       fn_fields = TREE_CHAIN (fn_fields))
    {
      tree fn_name = DECL_NAME (fn_fields);

      /* Clear out this flag.

	 @@ Doug may figure out how to break
	 @@ this with nested classes and friends.  */
      DECL_IN_AGGR_P (fn_fields) = 0;

      /* Note here that a copy ctor is private, so we don't dare generate
 	 a default copy constructor for a class that has a member
 	 of this type without making sure they have access to it.  */
      if (fn_name == ctor_name)
 	{
 	  tree parmtypes = FUNCTION_ARG_CHAIN (fn_fields);
 	  tree parmtype = parmtypes ? TREE_VALUE (parmtypes) : void_type_node;
	  
 	  if (TREE_CODE (parmtype) == REFERENCE_TYPE
 	      && TYPE_MAIN_VARIANT (TREE_TYPE (parmtype)) == t)
 	    {
 	      if (TREE_CHAIN (parmtypes) == NULL_TREE
 		  || TREE_CHAIN (parmtypes) == void_list_node
 		  || TREE_PURPOSE (TREE_CHAIN (parmtypes)))
 		{
 		  if (TREE_PROTECTED (fn_fields))
 		    TYPE_HAS_NONPUBLIC_CTOR (t) = 1;
 		  else if (TREE_PRIVATE (fn_fields))
 		    TYPE_HAS_NONPUBLIC_CTOR (t) = 2;
 		}
 	    }
	}
      else if (fn_name == ansi_opname[(int) MODIFY_EXPR])
	{
	  tree parmtype = TREE_VALUE (FUNCTION_ARG_CHAIN (fn_fields));

	  if (copy_assignment_arg_p (parmtype, DECL_VIRTUAL_P (fn_fields)))
	    {
	      if (TREE_PROTECTED (fn_fields))
		TYPE_HAS_NONPUBLIC_ASSIGN_REF (t) = 1;
	      else if (TREE_PRIVATE (fn_fields))
		TYPE_HAS_NONPUBLIC_ASSIGN_REF (t) = 2;
	    }
	}
    }

  if (TYPE_HAS_DESTRUCTOR (t) && !TREE_VEC_ELT (method_vec, 1))
    /* We thought there was a destructor, but there wasn't.  Some
       parse errors cause this anomalous situation.  */
    TYPE_HAS_DESTRUCTOR (t) = 0;
    
  /* Issue warnings about private constructors and such.  If there are
     no methods, then some public defaults are generated.  */
  maybe_warn_about_overly_private_class (t);

  /* Now sort the methods.  */
  while (len > 2 && TREE_VEC_ELT (method_vec, len-1) == NULL_TREE)
    len--;
  TREE_VEC_LENGTH (method_vec) = len;

  /* The type conversion ops have to live at the front of the vec, so we
     can't sort them.  */
  for (slot = 2; slot < len; ++slot)
    {
      tree fn = TREE_VEC_ELT (method_vec, slot);
  
      if (!DECL_CONV_FN_P (OVL_CURRENT (fn)))
	break;
    }
  if (len - slot > 1)
    qsort (&TREE_VEC_ELT (method_vec, slot), len-slot, sizeof (tree),
	   (int (*)(const void *, const void *))method_name_cmp);
}

/* Emit error when a duplicate definition of a type is seen.  Patch up.  */

void
duplicate_tag_error (t)
     tree t;
{
  cp_error ("redefinition of `%#T'", t);
  cp_error_at ("previous definition here", t);

  /* Pretend we haven't defined this type.  */

  /* All of the component_decl's were TREE_CHAINed together in the parser.
     finish_struct_methods walks these chains and assembles all methods with
     the same base name into DECL_CHAINs. Now we don't need the parser chains
     anymore, so we unravel them.  */

  /* This used to be in finish_struct, but it turns out that the
     TREE_CHAIN is used by dbxout_type_methods and perhaps some other
     things...  */
  if (CLASSTYPE_METHOD_VEC (t)) 
    {
      tree method_vec = CLASSTYPE_METHOD_VEC (t);
      int i, len  = TREE_VEC_LENGTH (method_vec);
      for (i = 0; i < len; i++)
	{
	  tree unchain = TREE_VEC_ELT (method_vec, i);
	  while (unchain != NULL_TREE) 
	    {
	      TREE_CHAIN (OVL_CURRENT (unchain)) = NULL_TREE;
	      unchain = OVL_NEXT (unchain);
	    }
	}
    }

  if (TYPE_LANG_SPECIFIC (t))
    {
      tree binfo = TYPE_BINFO (t);
      int interface_only = CLASSTYPE_INTERFACE_ONLY (t);
      int interface_unknown = CLASSTYPE_INTERFACE_UNKNOWN (t);
      tree template_info = CLASSTYPE_TEMPLATE_INFO (t);
      int use_template = CLASSTYPE_USE_TEMPLATE (t);

      bzero ((char *) TYPE_LANG_SPECIFIC (t), sizeof (struct lang_type));
      BINFO_BASETYPES(binfo) = NULL_TREE;

      TYPE_BINFO (t) = binfo;
      CLASSTYPE_INTERFACE_ONLY (t) = interface_only;
      SET_CLASSTYPE_INTERFACE_UNKNOWN_X (t, interface_unknown);
      TYPE_REDEFINED (t) = 1;
      CLASSTYPE_TEMPLATE_INFO (t) = template_info;
      CLASSTYPE_USE_TEMPLATE (t) = use_template;
    }
  TYPE_SIZE (t) = NULL_TREE;
  TYPE_MODE (t) = VOIDmode;
  TYPE_FIELDS (t) = NULL_TREE;
  TYPE_METHODS (t) = NULL_TREE;
  TYPE_VFIELD (t) = NULL_TREE;
  TYPE_CONTEXT (t) = NULL_TREE;
  TYPE_NONCOPIED_PARTS (t) = NULL_TREE;
}

/* Construct the initializer for BINFOs virtual function table.  */

static tree
build_vtbl_initializer (binfo)
     tree binfo;
{
  tree v = BINFO_VIRTUALS (binfo);
  tree inits = NULL_TREE;

  /* Process the RTTI stuff at the head of the list.  If we're not
     using vtable thunks, then the RTTI entry is just an ordinary
     function, and we can process it just like the other virtual
     function entries.  */
  if (!CLASSTYPE_COM_INTERFACE (BINFO_TYPE (binfo))
      && flag_vtable_thunks)
    {
      tree offset;
      tree init;

      /* The first entry is an offset.  */
      offset = TREE_PURPOSE (v);
      my_friendly_assert (TREE_CODE (offset) == INTEGER_CST,
			  19990727);

      /* Convert the offset to look like a function pointer, so that
	 we can put it in the vtable.  */
      init = build1 (NOP_EXPR, vfunc_ptr_type_node, offset);
      TREE_CONSTANT (init) = 1;
      init = build_vtable_entry (integer_zero_node, init);
      inits = tree_cons (NULL_TREE, init, inits);

      /* Even in this case, the second entry (the tdesc pointer) is
	 just an ordinary function.  */
      v = TREE_CHAIN (v);
    }

  /* Go through all the ordinary virtual functions, building up
     initializers.  */
  while (v)
    {
      tree delta;
      tree fn;
      tree init;

      /* Pull the offset for `this', and the function to call, out of
	 the list.  */
      delta = TREE_PURPOSE (v);
      fn = TREE_VALUE (v);
      my_friendly_assert (TREE_CODE (delta) == INTEGER_CST, 19990727);
      my_friendly_assert (TREE_CODE (fn) == FUNCTION_DECL, 19990727);

      /* You can't call an abstract virtual function; it's abstract.
	 So, we replace these functions with __pure_virtual.  */
      if (DECL_PURE_VIRTUAL_P (fn))
	fn = abort_fndecl;

      /* Package up that information for the vtable.  */
      init = build_vtable_entry_for_fn (delta, fn);
      /* And add it to the chain of initializers.  */
      inits = tree_cons (NULL_TREE, init, inits);

      /* Keep going.  */
      v = TREE_CHAIN (v);
    }

  /* The initializers were built up in reverse order; straighten them
     out now.  */
  inits = nreverse (inits);
  /* Package all the initializers up as an array initializer.  */
  return build_nt (CONSTRUCTOR, NULL_TREE, inits);
}

/* finish up all new vtables.  */

static void
finish_vtbls (binfo, do_self, t)
     tree binfo;
     int do_self;
     tree t;
{
  tree binfos = BINFO_BASETYPES (binfo);
  int i, n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0;

  /* Should we use something besides CLASSTYPE_VFIELDS? */
  if (do_self && CLASSTYPE_VFIELDS (BINFO_TYPE (binfo)))
    {
      if (BINFO_NEW_VTABLE_MARKED (binfo))
	{
	  tree decl, context;

	  decl = BINFO_VTABLE (binfo);
	  context = DECL_CONTEXT (decl);
	  DECL_CONTEXT (decl) = 0;
	  DECL_INITIAL (decl) = build_vtbl_initializer (binfo);
	  cp_finish_decl (decl, DECL_INITIAL (decl), NULL_TREE, 0);
	  DECL_CONTEXT (decl) = context;
	}
      CLEAR_BINFO_NEW_VTABLE_MARKED (binfo);
    }

  for (i = 0; i < n_baselinks; i++)
    {
      tree base_binfo = TREE_VEC_ELT (binfos, i);
      int is_not_base_vtable
	= i != CLASSTYPE_VFIELD_PARENT (BINFO_TYPE (binfo));
      if (TREE_VIA_VIRTUAL (base_binfo))
	base_binfo = BINFO_FOR_VBASE (BINFO_TYPE (base_binfo), t);
      finish_vtbls (base_binfo, is_not_base_vtable, t);
    }
}

/* True if we should override the given BASE_FNDECL with the given
   FNDECL.  */

static int
overrides (fndecl, base_fndecl)
     tree fndecl, base_fndecl;
{
  /* Destructors have special names.  */
  if (DESTRUCTOR_NAME_P (DECL_ASSEMBLER_NAME (base_fndecl))
      && DESTRUCTOR_NAME_P (DECL_ASSEMBLER_NAME (fndecl)))
    return 1;
  if (DESTRUCTOR_NAME_P (DECL_ASSEMBLER_NAME (base_fndecl))
      || DESTRUCTOR_NAME_P (DECL_ASSEMBLER_NAME (fndecl)))
    return 0;
  if (DECL_NAME (fndecl) == DECL_NAME (base_fndecl))
    {
      tree types, base_types;
#if 0
      retypes = TREE_TYPE (TREE_TYPE (fndecl));
      base_retypes = TREE_TYPE (TREE_TYPE (base_fndecl));
#endif
      types = TYPE_ARG_TYPES (TREE_TYPE (fndecl));
      base_types = TYPE_ARG_TYPES (TREE_TYPE (base_fndecl));
      if ((TYPE_QUALS (TREE_TYPE (TREE_VALUE (base_types)))
	   == TYPE_QUALS (TREE_TYPE (TREE_VALUE (types))))
	  && compparms (TREE_CHAIN (base_types), TREE_CHAIN (types)))
	return 1;
    }
  return 0;
}

static tree
get_class_offset_1 (parent, binfo, context, t, fndecl)
     tree parent, binfo, context, t, fndecl;
{
  tree binfos = BINFO_BASETYPES (binfo);
  int i, n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0;
  tree rval = NULL_TREE;

  if (binfo == parent)
    return error_mark_node;

  for (i = 0; i < n_baselinks; i++)
    {
      tree base_binfo = TREE_VEC_ELT (binfos, i);
      tree nrval;

      if (TREE_VIA_VIRTUAL (base_binfo))
	base_binfo = BINFO_FOR_VBASE (BINFO_TYPE (base_binfo), t);
      nrval = get_class_offset_1 (parent, base_binfo, context, t, fndecl);
      /* See if we have a new value */
      if (nrval && (nrval != error_mark_node || rval==0))
	{
	  /* Only compare if we have two offsets */
	  if (rval && rval != error_mark_node
	      && ! tree_int_cst_equal (nrval, rval))
	    {
	      /* Only give error if the two offsets are different */
	      error ("every virtual function must have a unique final overrider");
	      cp_error ("  found two (or more) `%T' class subobjects in `%T'", context, t);
	      cp_error ("  with virtual `%D' from virtual base class", fndecl);
	      return rval;
	    }
	  rval = nrval;
	}
	
      if (rval && BINFO_TYPE (binfo) == context)
	{
	  my_friendly_assert (rval == error_mark_node
			      || tree_int_cst_equal (rval, BINFO_OFFSET (binfo)), 999);
	  rval = BINFO_OFFSET (binfo);
	}
    }
  return rval;
}

/* Get the offset to the CONTEXT subobject that is related to the
   given BINFO.  */

static tree
get_class_offset (context, t, binfo, fndecl)
     tree context, t, binfo, fndecl;
{
  tree first_binfo = binfo;
  tree offset;
  int i;

  if (context == t)
    return integer_zero_node;

  if (BINFO_TYPE (binfo) == context)
    return BINFO_OFFSET (binfo);

  /* Check less derived binfos first.  */
  while (BINFO_BASETYPES (binfo)
	 && (i=CLASSTYPE_VFIELD_PARENT (BINFO_TYPE (binfo))) != -1)
    {
      tree binfos = BINFO_BASETYPES (binfo);
      binfo = TREE_VEC_ELT (binfos, i);
      if (BINFO_TYPE (binfo) == context)
	return BINFO_OFFSET (binfo);
    }

  /* Ok, not found in the less derived binfos, now check the more
     derived binfos.  */
  offset = get_class_offset_1 (first_binfo, TYPE_BINFO (t), context, t, fndecl);
  if (offset==0 || TREE_CODE (offset) != INTEGER_CST)
    my_friendly_abort (999);	/* we have to find it.  */
  return offset;
}

/* Skip RTTI information at the front of the virtual list.  */

unsigned HOST_WIDE_INT
skip_rtti_stuff (virtuals, t)
     tree *virtuals, t;
{
  int n;

  if (CLASSTYPE_COM_INTERFACE (t))
    return 0;

  n = 0;
  if (*virtuals)
    {
      /* We always reserve a slot for the offset/tdesc entry.  */
      ++n;
      *virtuals = TREE_CHAIN (*virtuals);
    }
  if (flag_vtable_thunks && *virtuals)
    {
      /* The second slot is reserved for the tdesc pointer when thunks
         are used.  */
      ++n;
      *virtuals = TREE_CHAIN (*virtuals);
    }
  return n;
}

static void
modify_one_vtable (binfo, t, fndecl)
     tree binfo, t, fndecl;
{
  tree virtuals = BINFO_VIRTUALS (binfo);
  unsigned HOST_WIDE_INT n;
  
  /* update rtti entry */
  if (flag_rtti)
    {
      if (binfo == TYPE_BINFO (t))
	{
	  if (! BINFO_NEW_VTABLE_MARKED (binfo))
	    build_vtable (TYPE_BINFO (DECL_CONTEXT (TYPE_VFIELD (t))), t);
	}
      else
	{
	  if (! BINFO_NEW_VTABLE_MARKED (binfo))
	    prepare_fresh_vtable (binfo, t);
	}
    }
  if (fndecl == NULL_TREE)
    return;

  n = skip_rtti_stuff (&virtuals, BINFO_TYPE (binfo));

  while (virtuals)
    {
      tree current_fndecl = TREE_VALUE (virtuals);

      /* We should never have an instance of __pure_virtual on the
	 BINFO_VIRTUALS list.  If we do, then we will never notice
	 that the function that should have been there instead has
	 been overridden.  */
      my_friendly_assert (current_fndecl != abort_fndecl,
			  19990727);

      if (current_fndecl && overrides (fndecl, current_fndecl))
	{
	  tree base_offset, offset;
	  tree context = DECL_CLASS_CONTEXT (fndecl);
	  tree vfield = TYPE_VFIELD (t);
	  tree this_offset;

	  offset = get_class_offset (context, t, binfo, fndecl);

	  /* Find the right offset for the this pointer based on the
	     base class we just found.  We have to take into
	     consideration the virtual base class pointers that we
	     stick in before the virtual function table pointer.

	     Also, we want just the delta between the most base class
	     that we derived this vfield from and us.  */
	  base_offset = size_binop (PLUS_EXPR,
				    get_derived_offset (binfo, DECL_CONTEXT (current_fndecl)),
				    BINFO_OFFSET (binfo));
	  this_offset = ssize_binop (MINUS_EXPR, offset, base_offset);

	  if (binfo == TYPE_BINFO (t))
	    {
	      /* In this case, it is *type*'s vtable we are modifying.
		 We start with the approximation that it's vtable is that
		 of the immediate base class.  */
	      if (! BINFO_NEW_VTABLE_MARKED (binfo))
		build_vtable (TYPE_BINFO (DECL_CONTEXT (vfield)), t);
	    }
	  else
	    {
	      /* This is our very own copy of `basetype' to play with.
		 Later, we will fill in all the virtual functions
		 that override the virtual functions in these base classes
		 which are not defined by the current type.  */
	      if (! BINFO_NEW_VTABLE_MARKED (binfo))
		prepare_fresh_vtable (binfo, t);
	    }

#ifdef NOTQUITE
	  cp_warning ("in %D", DECL_NAME (BINFO_VTABLE (binfo)));
#endif
	  modify_vtable_entry (get_vtable_entry_n (BINFO_VIRTUALS (binfo), n),
			       this_offset,
			       fndecl);
	}
      ++n;
      virtuals = TREE_CHAIN (virtuals);
    }
}

/* These are the ones that are not through virtual base classes.  */

static void
modify_all_direct_vtables (binfo, do_self, t, fndecl)
     tree binfo;
     int do_self;
     tree t, fndecl;
{
  tree binfos = BINFO_BASETYPES (binfo);
  int i, n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0;

  /* Should we use something besides CLASSTYPE_VFIELDS? */
  if (do_self && CLASSTYPE_VFIELDS (BINFO_TYPE (binfo)))
    modify_one_vtable (binfo, t, fndecl);

  for (i = 0; i < n_baselinks; i++)
    {
      tree base_binfo = TREE_VEC_ELT (binfos, i);
      int is_not_base_vtable
	= i != CLASSTYPE_VFIELD_PARENT (BINFO_TYPE (binfo));
      if (! TREE_VIA_VIRTUAL (base_binfo))
	modify_all_direct_vtables (base_binfo, is_not_base_vtable, t, fndecl);
    }
}

/* Fixup all the delta entries in this one vtable that need updating.  */

static void
fixup_vtable_deltas1 (binfo, t)
     tree binfo, t;
{
  tree virtuals = BINFO_VIRTUALS (binfo);
  unsigned HOST_WIDE_INT n;
  
  n = skip_rtti_stuff (&virtuals, BINFO_TYPE (binfo));

  while (virtuals)
    {
      tree fndecl = TREE_VALUE (virtuals);
      tree delta = TREE_PURPOSE (virtuals);

      if (fndecl)
	{
	  tree base_offset, offset;
	  tree context = DECL_CLASS_CONTEXT (fndecl);
	  tree vfield = TYPE_VFIELD (t);
	  tree this_offset;

	  offset = get_class_offset (context, t, binfo, fndecl);

	  /* Find the right offset for the this pointer based on the
	     base class we just found.  We have to take into
	     consideration the virtual base class pointers that we
	     stick in before the virtual function table pointer.

	     Also, we want just the delta between the most base class
	     that we derived this vfield from and us.  */
	  base_offset = size_binop (PLUS_EXPR,
				    get_derived_offset (binfo,
							DECL_CONTEXT (fndecl)),
				    BINFO_OFFSET (binfo));
	  this_offset = ssize_binop (MINUS_EXPR, offset, base_offset);

	  if (! tree_int_cst_equal (this_offset, delta))
	    {
	      /* Make sure we can modify the derived association with immunity.  */
	      if (binfo == TYPE_BINFO (t))
		{
		  /* In this case, it is *type*'s vtable we are modifying.
		     We start with the approximation that it's vtable is that
		     of the immediate base class.  */
		  if (! BINFO_NEW_VTABLE_MARKED (binfo))
		    build_vtable (TYPE_BINFO (DECL_CONTEXT (vfield)), t);
		}
	      else
		{
		  /* This is our very own copy of `basetype' to play with.
		     Later, we will fill in all the virtual functions
		     that override the virtual functions in these base classes
		     which are not defined by the current type.  */
		  if (! BINFO_NEW_VTABLE_MARKED (binfo))
		    prepare_fresh_vtable (binfo, t);
		}

	      modify_vtable_entry (get_vtable_entry_n (BINFO_VIRTUALS (binfo), n),
				   this_offset,
				   fndecl);
	    }
	}
      ++n;
      virtuals = TREE_CHAIN (virtuals);
    }
}

/* Fixup all the delta entries in all the direct vtables that need updating.
   This happens when we have non-overridden virtual functions from a
   virtual base class, that are at a different offset, in the new
   hierarchy, because the layout of the virtual bases has changed.  */

static void
fixup_vtable_deltas (binfo, init_self, t)
     tree binfo;
     int init_self;
     tree t;
{
  tree binfos = BINFO_BASETYPES (binfo);
  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);
      int is_not_base_vtable
	= i != CLASSTYPE_VFIELD_PARENT (BINFO_TYPE (binfo));
      if (! TREE_VIA_VIRTUAL (base_binfo))
	fixup_vtable_deltas (base_binfo, is_not_base_vtable, t);
    }
  /* Should we use something besides CLASSTYPE_VFIELDS? */
  if (init_self && CLASSTYPE_VFIELDS (BINFO_TYPE (binfo)))
    fixup_vtable_deltas1 (binfo, t);
}

/* These are the ones that are through virtual base classes.  */

static void
modify_all_indirect_vtables (binfo, do_self, via_virtual, t, fndecl)
     tree binfo;
     int do_self, via_virtual;
     tree t, fndecl;
{
  tree binfos = BINFO_BASETYPES (binfo);
  int i, n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0;

  /* Should we use something besides CLASSTYPE_VFIELDS? */
  if (do_self && via_virtual && CLASSTYPE_VFIELDS (BINFO_TYPE (binfo)))
    modify_one_vtable (binfo, t, fndecl);

  for (i = 0; i < n_baselinks; i++)
    {
      tree base_binfo = TREE_VEC_ELT (binfos, i);
      int is_not_base_vtable
	= i != CLASSTYPE_VFIELD_PARENT (BINFO_TYPE (binfo));
      if (TREE_VIA_VIRTUAL (base_binfo))
	{
	  via_virtual = 1;
	  base_binfo = BINFO_FOR_VBASE (BINFO_TYPE (base_binfo), t);
	}
      modify_all_indirect_vtables (base_binfo, is_not_base_vtable, via_virtual, t, fndecl);
    }
}

static void
modify_all_vtables (t, fndecl)
     tree t;
     tree fndecl;
{
  /* Do these first, so that we will make use of any non-virtual class's
     vtable, over a virtual classes vtable.  */
  modify_all_direct_vtables (TYPE_BINFO (t), 1, t, fndecl);
  if (TYPE_USES_VIRTUAL_BASECLASSES (t))
    modify_all_indirect_vtables (TYPE_BINFO (t), 1, 0, t, fndecl);
}

/* Here, we already know that they match in every respect.
   All we have to check is where they had their declarations.  */

static int 
strictly_overrides (fndecl1, fndecl2)
     tree fndecl1, fndecl2;
{
  int distance = get_base_distance (DECL_CLASS_CONTEXT (fndecl2),
				    DECL_CLASS_CONTEXT (fndecl1),
				    0, (tree *)0);
  if (distance == -2 || distance > 0)
    return 1;
  return 0;
}

/* Merge overrides for one vtable.
   If we want to merge in same function, we are fine.
   else
     if one has a DECL_CLASS_CONTEXT that is a parent of the
       other, than choose the more derived one
     else
       potentially ill-formed (see 10.3 [class.virtual])
       we have to check later to see if there was an
       override in this class.  If there was ok, if not
       then it is ill-formed.  (mrs)

   We take special care to reuse a vtable, if we can.  */

static void
override_one_vtable (binfo, old, t)
     tree binfo, old, t;
{
  tree virtuals = BINFO_VIRTUALS (binfo);
  tree old_virtuals = BINFO_VIRTUALS (old);
  enum { REUSE_NEW, REUSE_OLD, UNDECIDED, NEITHER } choose = UNDECIDED;

  /* If we have already committed to modifying it, then don't try and
     reuse another vtable.  */
  if (BINFO_NEW_VTABLE_MARKED (binfo))
    choose = NEITHER;

  skip_rtti_stuff (&virtuals, BINFO_TYPE (binfo));
  skip_rtti_stuff (&old_virtuals, BINFO_TYPE (binfo));

  while (virtuals)
    {
      tree fndecl = TREE_VALUE (virtuals);
      tree old_fndecl = TREE_VALUE (old_virtuals);

      /* First check to see if they are the same.  */
      if (DECL_ASSEMBLER_NAME (fndecl) == DECL_ASSEMBLER_NAME (old_fndecl))
	{
	  /* No need to do anything.  */
	}
      else if (strictly_overrides (fndecl, old_fndecl))
	{
	  if (choose == UNDECIDED)
	    choose = REUSE_NEW;
	  else if (choose == REUSE_OLD)
	    {
	      choose = NEITHER;
	      if (! BINFO_NEW_VTABLE_MARKED (binfo))
		{
		  prepare_fresh_vtable (binfo, t);
		  override_one_vtable (binfo, old, t);
		  return;
		}
	    }
	}
      else if (strictly_overrides (old_fndecl, fndecl))
	{
	  if (choose == UNDECIDED)
	    choose = REUSE_OLD;
	  else if (choose == REUSE_NEW)
	    {
	      choose = NEITHER;
	      if (! BINFO_NEW_VTABLE_MARKED (binfo))
		{
		  prepare_fresh_vtable (binfo, t);
		  override_one_vtable (binfo, old, t);
		  return;
		}
	      TREE_VALUE (virtuals) = TREE_VALUE (old_virtuals);
	    }
	  else if (choose == NEITHER)
	    {
	      TREE_VALUE (virtuals) = TREE_VALUE (old_virtuals);
	    }  
	}
      else
	{
	  choose = NEITHER;
	  if (! BINFO_NEW_VTABLE_MARKED (binfo))
	    {
	      prepare_fresh_vtable (binfo, t);
	      override_one_vtable (binfo, old, t);
	      return;
	    }
	  {
	    /* This MUST be overridden, or the class is ill-formed.  */
	    tree fndecl = TREE_VALUE (virtuals);

	    fndecl = copy_node (fndecl);
	    copy_lang_decl (fndecl);
	    DECL_NEEDS_FINAL_OVERRIDER_P (fndecl) = 1;
	    /* Make sure we search for it later.  */
	    if (! CLASSTYPE_PURE_VIRTUALS (t))
	      CLASSTYPE_PURE_VIRTUALS (t) = error_mark_node;

	    /* We can use integer_zero_node, as we will core dump
	       if this is used anyway.  */
	    TREE_PURPOSE (virtuals) = integer_zero_node;
	    TREE_VALUE (virtuals) = fndecl;
	  }
	}
      virtuals = TREE_CHAIN (virtuals);
      old_virtuals = TREE_CHAIN (old_virtuals);
    }

  /* Let's reuse the old vtable.  */
  if (choose == REUSE_OLD)
    {
      BINFO_VTABLE (binfo) = BINFO_VTABLE (old);
      BINFO_VIRTUALS (binfo) = BINFO_VIRTUALS (old);
    }
}

/* Merge in overrides for virtual bases.
   BINFO is the hierarchy we want to modify, and OLD has the potential
   overrides.  */

static void
merge_overrides (binfo, old, do_self, t)
     tree binfo, old;
     int do_self;
     tree t;
{
  tree binfos = BINFO_BASETYPES (binfo);
  tree old_binfos = BINFO_BASETYPES (old);
  int i, n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0;

  /* Should we use something besides CLASSTYPE_VFIELDS? */
  if (do_self && CLASSTYPE_VFIELDS (BINFO_TYPE (binfo)))
    {
      override_one_vtable (binfo, old, t);
    }

  for (i = 0; i < n_baselinks; i++)
    {
      tree base_binfo = TREE_VEC_ELT (binfos, i);
      tree old_base_binfo = TREE_VEC_ELT (old_binfos, i);
      int is_not_base_vtable
	= i != CLASSTYPE_VFIELD_PARENT (BINFO_TYPE (binfo));
      if (! TREE_VIA_VIRTUAL (base_binfo))
	merge_overrides (base_binfo, old_base_binfo, is_not_base_vtable, t);
    }
}

/* Get the base virtual function declarations in T that are either
   overridden or hidden by FNDECL as a list.  We set TREE_PURPOSE with
   the overrider/hider.  */

static tree
get_basefndecls (fndecl, t)
     tree fndecl, t;
{
  tree methods = TYPE_METHODS (t);
  tree base_fndecls = NULL_TREE;
  tree binfos = BINFO_BASETYPES (TYPE_BINFO (t));
  int i, n_baseclasses = binfos ? TREE_VEC_LENGTH (binfos) : 0;

  while (methods)
    {
      if (TREE_CODE (methods) == FUNCTION_DECL
	  && DECL_VINDEX (methods) != NULL_TREE
	  && DECL_NAME (fndecl) == DECL_NAME (methods))
	base_fndecls = tree_cons (fndecl, methods, base_fndecls);

      methods = TREE_CHAIN (methods);
    }

  if (base_fndecls)
    return base_fndecls;

  for (i = 0; i < n_baseclasses; i++)
    {
      tree base_binfo = TREE_VEC_ELT (binfos, i);
      tree basetype = BINFO_TYPE (base_binfo);

      base_fndecls = chainon (get_basefndecls (fndecl, basetype),
			      base_fndecls);
    }

  return base_fndecls;
}

/* Mark the functions that have been hidden with their overriders.
   Since we start out with all functions already marked with a hider,
   no need to mark functions that are just hidden.

   Subroutine of warn_hidden.  */

static void
mark_overriders (fndecl, base_fndecls)
     tree fndecl, base_fndecls;
{
  for (; base_fndecls; base_fndecls = TREE_CHAIN (base_fndecls))
    {
      if (overrides (fndecl, TREE_VALUE (base_fndecls)))
	TREE_PURPOSE (base_fndecls) = fndecl;
    }
}

/* If this declaration supersedes the declaration of
   a method declared virtual in the base class, then
   mark this field as being virtual as well.  */

static void
check_for_override (decl, ctype)
     tree decl, ctype;
{
  tree binfos = BINFO_BASETYPES (TYPE_BINFO (ctype));
  int i, n_baselinks = binfos ? TREE_VEC_LENGTH (binfos) : 0;
  int virtualp = DECL_VIRTUAL_P (decl);
  int found_overriden_fn = 0;

  for (i = 0; i < n_baselinks; i++)
    {
      tree base_binfo = TREE_VEC_ELT (binfos, i);
      if (TYPE_POLYMORPHIC_P (BINFO_TYPE (base_binfo)))
	{
	  tree tmp = get_matching_virtual
	    (base_binfo, decl,
	     DESTRUCTOR_NAME_P (DECL_ASSEMBLER_NAME (decl)));

	  if (tmp && !found_overriden_fn)
	    {
	      /* If this function overrides some virtual in some base
		 class, then the function itself is also necessarily
		 virtual, even if the user didn't explicitly say so.  */
	      DECL_VIRTUAL_P (decl) = 1;

	      /* The TMP we really want is the one from the deepest
		 baseclass on this path, taking care not to
		 duplicate if we have already found it (via another
		 path to its virtual baseclass.  */
	      if (TREE_CODE (TREE_TYPE (decl)) == FUNCTION_TYPE)
		{
		  cp_error_at ("`static %#D' cannot be declared", decl);
		  cp_error_at ("  since `virtual %#D' declared in base class",
			       tmp);
		  break;
		}
	      virtualp = 1;

	      DECL_VINDEX (decl)
		= tree_cons (NULL_TREE, tmp, DECL_VINDEX (decl));
	      
	      /* We now know that DECL overrides something,
		 which is all that is important.  But, we must
		 continue to iterate through all the base-classes
		 in order to allow get_matching_virtual to check for
		 various illegal overrides.  */
	      found_overriden_fn = 1;
	    }
	}
    }
  if (virtualp)
    {
      if (DECL_VINDEX (decl) == NULL_TREE)
	DECL_VINDEX (decl) = error_mark_node;
      IDENTIFIER_VIRTUAL_P (DECL_NAME (decl)) = 1;
    }
}

/* Warn about hidden virtual functions that are not overridden in t.
   We know that constructors and destructors don't apply.  */

void
warn_hidden (t)
     tree t;
{
  tree method_vec = CLASSTYPE_METHOD_VEC (t);
  int n_methods = method_vec ? TREE_VEC_LENGTH (method_vec) : 0;
  int i;

  /* We go through each separately named virtual function.  */
  for (i = 2; i < n_methods && TREE_VEC_ELT (method_vec, i); ++i)
    {
      tree fns = TREE_VEC_ELT (method_vec, i);
      tree fndecl;

      tree base_fndecls = NULL_TREE;
      tree binfos = BINFO_BASETYPES (TYPE_BINFO (t));
      int i, n_baseclasses = binfos ? TREE_VEC_LENGTH (binfos) : 0;

      /* First see if we have any virtual functions in this batch.  */
      for (; fns; fns = OVL_NEXT (fns))
	{
	  fndecl = OVL_CURRENT (fns);
	  if (DECL_VINDEX (fndecl))
	    break;
	}

      if (fns == NULL_TREE)
	continue;

      /* First we get a list of all possible functions that might be
	 hidden from each base class.  */
      for (i = 0; i < n_baseclasses; i++)
	{
	  tree base_binfo = TREE_VEC_ELT (binfos, i);
	  tree basetype = BINFO_TYPE (base_binfo);

	  base_fndecls = chainon (get_basefndecls (fndecl, basetype),
				  base_fndecls);
	}

      fns = OVL_NEXT (fns);

      /* ...then mark up all the base functions with overriders, preferring
	 overriders to hiders.  */
      if (base_fndecls)
	for (; fns; fns = OVL_NEXT (fns))
	  {
	    fndecl = OVL_CURRENT (fns);
	    if (DECL_VINDEX (fndecl))
	      mark_overriders (fndecl, base_fndecls);
	  }

      /* Now give a warning for all base functions without overriders,
	 as they are hidden.  */
      for (; base_fndecls; base_fndecls = TREE_CHAIN (base_fndecls))
	{
	  if (! overrides (TREE_PURPOSE (base_fndecls),
			   TREE_VALUE (base_fndecls)))
	    {
	      /* Here we know it is a hider, and no overrider exists.  */
	      cp_warning_at ("`%D' was hidden", TREE_VALUE (base_fndecls));
	      cp_warning_at ("  by `%D'", TREE_PURPOSE (base_fndecls));
	    }
	}
    }
}

/* Check for things that are invalid.  There are probably plenty of other
   things we should check for also.  */

static void
finish_struct_anon (t)
     tree t;
{
  tree field;

  for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field))
    {
      if (TREE_STATIC (field))
	continue;
      if (TREE_CODE (field) != FIELD_DECL)
	continue;

      if (DECL_NAME (field) == NULL_TREE
	  && ANON_AGGR_TYPE_P (TREE_TYPE (field)))
	{
	  tree elt = TYPE_FIELDS (TREE_TYPE (field));
	  for (; elt; elt = TREE_CHAIN (elt))
	    {
	      if (DECL_ARTIFICIAL (elt))
		continue;

	      if (DECL_NAME (elt) == constructor_name (t))
		cp_pedwarn_at ("ANSI C++ forbids member `%D' with same name as enclosing class",
			       elt);

	      if (TREE_CODE (elt) != FIELD_DECL)
		{
		  cp_pedwarn_at ("`%#D' invalid; an anonymous union can only have non-static data members",
				 elt);
		  continue;
		}

	      if (TREE_PRIVATE (elt))
		cp_pedwarn_at ("private member `%#D' in anonymous union",
			       elt);
	      else if (TREE_PROTECTED (elt))
		cp_pedwarn_at ("protected member `%#D' in anonymous union",
			       elt);

	      TREE_PRIVATE (elt) = TREE_PRIVATE (field);
	      TREE_PROTECTED (elt) = TREE_PROTECTED (field);
	    }
	}
    }
}

extern int interface_only, interface_unknown;

/* Create default constructors, assignment operators, and so forth for
   the type indicated by T, if they are needed.
   CANT_HAVE_DEFAULT_CTOR, CANT_HAVE_CONST_CTOR, and
   CANT_HAVE_ASSIGNMENT are nonzero if, for whatever reason, the class
   cannot have a default constructor, copy constructor taking a const
   reference argument, or an assignment operator, respectively.  If a
   virtual destructor is created, its DECL is returned; otherwise the
   return value is NULL_TREE.  */

static tree
add_implicitly_declared_members (t, cant_have_default_ctor,
				 cant_have_const_cctor,
				 cant_have_assignment)
     tree t;
     int cant_have_default_ctor;
     int cant_have_const_cctor;
     int cant_have_assignment;
{
  tree default_fn;
  tree implicit_fns = NULL_TREE;
  tree name = TYPE_IDENTIFIER (t);
  tree virtual_dtor = NULL_TREE;
  tree *f;

  /* Destructor.  */
  if (TYPE_NEEDS_DESTRUCTOR (t) && !TYPE_HAS_DESTRUCTOR (t))
    {
      default_fn = cons_up_default_function (t, name, 0);
      check_for_override (default_fn, t);

      /* If we couldn't make it work, then pretend we didn't need it.  */
      if (default_fn == void_type_node)
	TYPE_NEEDS_DESTRUCTOR (t) = 0;
      else
	{
	  TREE_CHAIN (default_fn) = implicit_fns;
	  implicit_fns = default_fn;

	  if (DECL_VINDEX (default_fn))
	    virtual_dtor = default_fn;
	}
    }
  TYPE_NEEDS_DESTRUCTOR (t) |= TYPE_HAS_DESTRUCTOR (t);

  /* Default constructor.  */
  if (! TYPE_HAS_CONSTRUCTOR (t) && ! cant_have_default_ctor)
    {
      default_fn = cons_up_default_function (t, name, 2);
      TREE_CHAIN (default_fn) = implicit_fns;
      implicit_fns = default_fn;
    }

  /* Copy constructor.  */
  if (! TYPE_HAS_INIT_REF (t) && ! TYPE_FOR_JAVA (t))
    {
      /* ARM 12.18: You get either X(X&) or X(const X&), but
	 not both.  --Chip  */
      default_fn = cons_up_default_function (t, name,
					     3 + cant_have_const_cctor);
      TREE_CHAIN (default_fn) = implicit_fns;
      implicit_fns = default_fn;
    }

  /* Assignment operator.  */
  if (! TYPE_HAS_ASSIGN_REF (t) && ! TYPE_FOR_JAVA (t))
    {
      default_fn = cons_up_default_function (t, name,
					     5 + cant_have_assignment);
      TREE_CHAIN (default_fn) = implicit_fns;
      implicit_fns = default_fn;
    }

  /* Now, hook all of the new functions on to TYPE_METHODS,
     and add them to the CLASSTYPE_METHOD_VEC.  */
  for (f = &implicit_fns; *f; f = &TREE_CHAIN (*f))
    add_method (t, 0, *f);
  *f = TYPE_METHODS (t);
  TYPE_METHODS (t) = implicit_fns;

  return virtual_dtor;
}

/* Subroutine of finish_struct_1.  Recursively count the number of fields
   in TYPE, including anonymous union members.  */

static int
count_fields (fields)
     tree fields;
{
  tree x;
  int n_fields = 0;
  for (x = fields; x; x = TREE_CHAIN (x))
    {
      if (TREE_CODE (x) == FIELD_DECL && ANON_AGGR_TYPE_P (TREE_TYPE (x)))
	n_fields += count_fields (TYPE_FIELDS (TREE_TYPE (x)));
      else
	n_fields += 1;
    }
  return n_fields;
}

/* Subroutine of finish_struct_1.  Recursively add all the fields in the
   TREE_LIST FIELDS to the TREE_VEC FIELD_VEC, starting at offset IDX.  */

static int
add_fields_to_vec (fields, field_vec, idx)
     tree fields, field_vec;
     int idx;
{
  tree x;
  for (x = fields; x; x = TREE_CHAIN (x))
    {
      if (TREE_CODE (x) == FIELD_DECL && ANON_AGGR_TYPE_P (TREE_TYPE (x)))
	idx = add_fields_to_vec (TYPE_FIELDS (TREE_TYPE (x)), field_vec, idx);
      else
	TREE_VEC_ELT (field_vec, idx++) = x;
    }
  return idx;
}

/* FIELD is a bit-field.  We are finishing the processing for its
   enclosing type.  Issue any appropriate messages and set appropriate
   flags.  */

static void
check_bitfield_decl (field)
     tree field;
{
  tree type = TREE_TYPE (field);

  /* Invalid bit-field size done by grokfield.  */
  /* Detect invalid bit-field type. Simply checking if TYPE is
     integral is insufficient, as that is the array core of the field
     type. If TREE_TYPE (field) is integral, then TYPE must be the same.  */
  if (DECL_INITIAL (field)
      && ! INTEGRAL_TYPE_P (TREE_TYPE (field)))
    {
      cp_error_at ("bit-field `%#D' with non-integral type", field);
      DECL_INITIAL (field) = NULL;
    }

  /* Detect and ignore out of range field width.  */
  if (DECL_INITIAL (field))
    {
      tree w = DECL_INITIAL (field);
      register int width = 0;

      /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs.  */
      STRIP_NOPS (w);

      /* detect invalid field size.  */
      if (TREE_CODE (w) == CONST_DECL)
	w = DECL_INITIAL (w);
      else if (TREE_READONLY_DECL_P (w))
	w = decl_constant_value (w);

      if (TREE_CODE (w) != INTEGER_CST)
	{
	  cp_error_at ("bit-field `%D' width not an integer constant",
		       field);
	  DECL_INITIAL (field) = NULL_TREE;
	}
      else if (width = TREE_INT_CST_LOW (w),
	       width < 0)
	{
	  DECL_INITIAL (field) = NULL;
	  cp_error_at ("negative width in bit-field `%D'", field);
	}
      else if (width == 0 && DECL_NAME (field) != 0)
	{
	  DECL_INITIAL (field) = NULL;
	  cp_error_at ("zero width for bit-field `%D'", field);
	}
      else if (width
	       > TYPE_PRECISION (long_long_unsigned_type_node))
	{
	  /* The backend will dump if you try to use something too
	     big; avoid that.  */
	  DECL_INITIAL (field) = NULL;
	  sorry ("bit-fields larger than %d bits",
		 TYPE_PRECISION (long_long_unsigned_type_node));
	  cp_error_at ("  in declaration of `%D'", field);
	}
      else if (width > TYPE_PRECISION (type)
	       && TREE_CODE (type) != ENUMERAL_TYPE
	       && TREE_CODE (type) != BOOLEAN_TYPE)
	cp_warning_at ("width of `%D' exceeds its type", field);
      else if (TREE_CODE (type) == ENUMERAL_TYPE
	       && ((min_precision (TYPE_MIN_VALUE (type),
				   TREE_UNSIGNED (type)) > width)
		   || (min_precision (TYPE_MAX_VALUE (type),
				      TREE_UNSIGNED (type)) > width)))
	cp_warning_at ("`%D' is too small to hold all values of `%#T'",
		       field, type);

      if (DECL_INITIAL (field))
	{
	  DECL_INITIAL (field) = NULL_TREE;
	  DECL_FIELD_SIZE (field) = width;
	  DECL_BIT_FIELD (field) = 1;

	  if (width == 0)
	    {
#ifdef EMPTY_FIELD_BOUNDARY
	      DECL_ALIGN (field) = MAX (DECL_ALIGN (field), 
					EMPTY_FIELD_BOUNDARY);
#endif
#ifdef PCC_BITFIELD_TYPE_MATTERS
	      if (PCC_BITFIELD_TYPE_MATTERS)
		DECL_ALIGN (field) = MAX (DECL_ALIGN (field), 
					  TYPE_ALIGN (type));
#endif
	    }
	}
    }
  else
    /* Non-bit-fields are aligned for their type.  */
    DECL_ALIGN (field) = MAX (DECL_ALIGN (field), TYPE_ALIGN (type));
}

/* FIELD is a non bit-field.  We are finishing the processing for its
   enclosing type T.  Issue any appropriate messages and set appropriate
   flags.  */

static void
check_field_decl (field, t, cant_have_const_ctor,
		  cant_have_default_ctor, no_const_asn_ref,
		  any_default_members)
     tree field;
     tree t;
     int *cant_have_const_ctor;
     int *cant_have_default_ctor;
     int *no_const_asn_ref;
     int *any_default_members;
{
  tree type = strip_array_types (TREE_TYPE (field));

  /* An anonymous union cannot contain any fields which would change
     the settings of CANT_HAVE_CONST_CTOR and friends.  */
  if (ANON_UNION_TYPE_P (type))
    ;
  /* And, we don't set TYPE_HAS_CONST_INIT_REF, etc., for anonymous
     structs.  So, we recurse through their fields here.  */
  else if (ANON_AGGR_TYPE_P (type))
    {
      tree fields;

      for (fields = TYPE_FIELDS (type); fields; fields = TREE_CHAIN (fields))
	if (TREE_CODE (field) == FIELD_DECL && !DECL_C_BIT_FIELD (field))
	  check_field_decl (fields, t, cant_have_const_ctor,
			    cant_have_default_ctor, no_const_asn_ref,
			    any_default_members);
    }
  /* Check members with class type for constructors, destructors,
     etc.  */
  else if (CLASS_TYPE_P (type))
    {
      /* Never let anything with uninheritable virtuals
	 make it through without complaint.  */
      abstract_virtuals_error (field, type);
		      
      if (TREE_CODE (t) == UNION_TYPE)
	{
	  if (TYPE_NEEDS_CONSTRUCTING (type))
	    cp_error_at ("member `%#D' with constructor not allowed in union",
			 field);
	  if (TYPE_NEEDS_DESTRUCTOR (type))
	    cp_error_at ("member `%#D' with destructor not allowed in union",
			 field);
	  if (TYPE_HAS_COMPLEX_ASSIGN_REF (type))
	    cp_error_at ("member `%#D' with copy assignment operator not allowed in union",
			 field);
	}
      else
	{
	  TYPE_NEEDS_CONSTRUCTING (t) |= TYPE_NEEDS_CONSTRUCTING (type);
	  TYPE_NEEDS_DESTRUCTOR (t) |= TYPE_NEEDS_DESTRUCTOR (type);
	  TYPE_HAS_COMPLEX_ASSIGN_REF (t) |= TYPE_HAS_COMPLEX_ASSIGN_REF (type);
	  TYPE_HAS_COMPLEX_INIT_REF (t) |= TYPE_HAS_COMPLEX_INIT_REF (type);
	}

      if (!TYPE_HAS_CONST_INIT_REF (type))
	*cant_have_const_ctor = 1;

      if (!TYPE_HAS_CONST_ASSIGN_REF (type))
	*no_const_asn_ref = 1;

      if (TYPE_HAS_CONSTRUCTOR (type)
	  && ! TYPE_HAS_DEFAULT_CONSTRUCTOR (type))
	*cant_have_default_ctor = 1;
    }
  if (DECL_INITIAL (field) != NULL_TREE)
    {
      /* `build_class_init_list' does not recognize
	 non-FIELD_DECLs.  */
      if (TREE_CODE (t) == UNION_TYPE && any_default_members != 0)
	cp_error_at ("multiple fields in union `%T' initialized");
      *any_default_members = 1;
    }

  /* Non-bit-fields are aligned for their type, except packed fields
     which require only BITS_PER_UNIT alignment.  */
  DECL_ALIGN (field) = MAX (DECL_ALIGN (field), 
			    (DECL_PACKED (field) 
			     ? BITS_PER_UNIT
			     : TYPE_ALIGN (TREE_TYPE (field))));
};

/* Check the data members (both static and non-static), class-scoped
   typedefs, etc., appearing in the declaration of T.  Issue
   appropriate diagnostics.  Sets ACCESS_DECLS to a list (in
   declaration order) of access declarations; each TREE_VALUE in this
   list is a USING_DECL.

   In addition, set the following flags:

     EMPTY_P
       The class is empty, i.e., contains no non-static data members.

     CANT_HAVE_DEFAULT_CTOR_P
       This class cannot have an implicitly generated default
       constructor.

     CANT_HAVE_CONST_CTOR_P
       This class cannot have an implicitly generated copy constructor
       taking a const reference.

     CANT_HAVE_CONST_ASN_REF
       This class cannot have an implicitly generated assignment
       operator taking a const reference.

   All of these flags should be initialized before calling this
   function.

   Returns a pointer to the end of the TYPE_FIELDs chain; additional
   fields can be added by adding to this chain.  */

static void
check_field_decls (t, access_decls, empty_p, 
		   cant_have_default_ctor_p, cant_have_const_ctor_p,
		   no_const_asn_ref_p)
     tree t;
     tree *access_decls;
     int *empty_p;
     int *cant_have_default_ctor_p;
     int *cant_have_const_ctor_p;
     int *no_const_asn_ref_p;
{
  tree *field;
  tree *next;
  int has_pointers;
  int any_default_members;

  /* First, delete any duplicate fields.  */
  delete_duplicate_fields (TYPE_FIELDS (t));

  /* Assume there are no access declarations.  */
  *access_decls = NULL_TREE;
  /* Assume this class has no pointer members.  */
  has_pointers = 0;
  /* Assume none of the members of this class have default
     initializations.  */
  any_default_members = 0;

  for (field = &TYPE_FIELDS (t); *field; field = next)
    {
      tree x = *field;
      tree type = TREE_TYPE (x);

      GNU_xref_member (current_class_name, x);

      next = &TREE_CHAIN (x);

      if (TREE_CODE (x) == FIELD_DECL)
	{
	  DECL_PACKED (x) |= TYPE_PACKED (t);

	  if (DECL_C_BIT_FIELD (x) && integer_zerop (DECL_INITIAL (x)))
	    /* We don't treat zero-width bitfields as making a class
	       non-empty.  */
	    ;
	  else
	    {
	      /* The class is non-empty.  */
	      *empty_p = 0;
	      /* The class is not even nearly empty.  */
	      CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
	    }
	}

      if (TREE_CODE (x) == USING_DECL)
	{
	  /* Prune the access declaration from the list of fields.  */
	  *field = TREE_CHAIN (x);

	  /* Save the access declarations for our caller.  */
	  *access_decls = tree_cons (NULL_TREE, x, *access_decls);

	  /* Since we've reset *FIELD there's no reason to skip to the
	     next field.  */
	  next = field;
	  continue;
	}

      if (TREE_CODE (x) == TYPE_DECL
	  || TREE_CODE (x) == TEMPLATE_DECL)
	continue;

      /* If we've gotten this far, it's a data member, possibly static,
	 or an enumerator.  */

      DECL_FIELD_CONTEXT (x) = t;

      /* ``A local class cannot have static data members.'' ARM 9.4 */
      if (current_function_decl && TREE_STATIC (x))
	cp_error_at ("field `%D' in local class cannot be static", x);

      /* Perform error checking that did not get done in
	 grokdeclarator.  */
      if (TREE_CODE (type) == FUNCTION_TYPE)
	{
	  cp_error_at ("field `%D' invalidly declared function type",
		       x);
	  type = build_pointer_type (type);
	  TREE_TYPE (x) = type;
	}
      else if (TREE_CODE (type) == METHOD_TYPE)
	{
	  cp_error_at ("field `%D' invalidly declared method type", x);
	  type = build_pointer_type (type);
	  TREE_TYPE (x) = type;
	}
      else if (TREE_CODE (type) == OFFSET_TYPE)
	{
	  cp_error_at ("field `%D' invalidly declared offset type", x);
	  type = build_pointer_type (type);
	  TREE_TYPE (x) = type;
	}

      if (type == error_mark_node)
	continue;
	  
      DECL_SAVED_INSNS (x) = 0;
      DECL_FIELD_SIZE (x) = 0;

      /* When this goes into scope, it will be a non-local reference.  */
      DECL_NONLOCAL (x) = 1;

      if (TREE_CODE (x) == CONST_DECL)
	continue;

      if (TREE_CODE (x) == VAR_DECL)
	{
	  if (TREE_CODE (t) == UNION_TYPE)
	    /* Unions cannot have static members.  */
	    cp_error_at ("field `%D' declared static in union", x);
	      
	  continue;
	}

      /* Now it can only be a FIELD_DECL.  */

      if (TREE_PRIVATE (x) || TREE_PROTECTED (x))
	CLASSTYPE_NON_AGGREGATE (t) = 1;

      /* If this is of reference type, check if it needs an init.
	 Also do a little ANSI jig if necessary.  */
      if (TREE_CODE (type) == REFERENCE_TYPE)
 	{
	  CLASSTYPE_NON_POD_P (t) = 1;
	  if (DECL_INITIAL (x) == NULL_TREE)
	    CLASSTYPE_REF_FIELDS_NEED_INIT (t) = 1;

	  /* ARM $12.6.2: [A member initializer list] (or, for an
	     aggregate, initialization by a brace-enclosed list) is the
	     only way to initialize nonstatic const and reference
	     members.  */
	  *cant_have_default_ctor_p = 1;
	  TYPE_HAS_COMPLEX_ASSIGN_REF (t) = 1;

	  if (! TYPE_HAS_CONSTRUCTOR (t) && extra_warnings)
	    {
	      if (DECL_NAME (x))
		cp_warning_at ("non-static reference `%#D' in class without a constructor", x);
	      else
		cp_warning_at ("non-static reference in class without a constructor", x);
	    }
	}

      type = strip_array_types (type);
      
      if (TREE_CODE (type) == POINTER_TYPE)
	has_pointers = 1;

      if (DECL_MUTABLE_P (x) || TYPE_HAS_MUTABLE_P (type))
	CLASSTYPE_HAS_MUTABLE (t) = 1;

      if (! pod_type_p (type)
	  /* For some reason, pointers to members are POD types themselves,
	     but are not allowed in POD structs.  Silly.  */
	  || TYPE_PTRMEM_P (type) || TYPE_PTRMEMFUNC_P (type))
	CLASSTYPE_NON_POD_P (t) = 1;

      /* If any field is const, the structure type is pseudo-const.  */
      if (CP_TYPE_CONST_P (type))
	{
	  C_TYPE_FIELDS_READONLY (t) = 1;
	  if (DECL_INITIAL (x) == NULL_TREE)
	    CLASSTYPE_READONLY_FIELDS_NEED_INIT (t) = 1;

	  /* ARM $12.6.2: [A member initializer list] (or, for an
	     aggregate, initialization by a brace-enclosed list) is the
	     only way to initialize nonstatic const and reference
	     members.  */
	  *cant_have_default_ctor_p = 1;
	  TYPE_HAS_COMPLEX_ASSIGN_REF (t) = 1;

	  if (! TYPE_HAS_CONSTRUCTOR (t) && extra_warnings)
	    {
	      if (DECL_NAME (x))
		cp_warning_at ("non-static const member `%#D' in class without a constructor", x);
	      else
		cp_warning_at ("non-static const member in class without a constructor", x);
	    }
	}
      /* A field that is pseudo-const makes the structure likewise.  */
      else if (IS_AGGR_TYPE (type))
	{
	  C_TYPE_FIELDS_READONLY (t) |= C_TYPE_FIELDS_READONLY (type);
	  CLASSTYPE_READONLY_FIELDS_NEED_INIT (t) 
	    |= CLASSTYPE_READONLY_FIELDS_NEED_INIT (type);
	}

      /* We set DECL_C_BIT_FIELD in grokbitfield.
	 If the type and width are valid, we'll also set DECL_BIT_FIELD.  */
      if (DECL_C_BIT_FIELD (x))
	check_bitfield_decl (x);
      else
	check_field_decl (x, t,
			  cant_have_const_ctor_p,
			  cant_have_default_ctor_p, 
			  no_const_asn_ref_p,
			  &any_default_members);
    }

  /* Effective C++ rule 11.  */
  if (has_pointers && warn_ecpp && TYPE_HAS_CONSTRUCTOR (t)
      && ! (TYPE_HAS_INIT_REF (t) && TYPE_HAS_ASSIGN_REF (t)))
    {
      cp_warning ("`%#T' has pointer data members", t);
      
      if (! TYPE_HAS_INIT_REF (t))
	{
	  cp_warning ("  but does not override `%T(const %T&)'", t, t);
	  if (! TYPE_HAS_ASSIGN_REF (t))
	    cp_warning ("  or `operator=(const %T&)'", t);
	}
      else if (! TYPE_HAS_ASSIGN_REF (t))
	cp_warning ("  but does not override `operator=(const %T&)'", t);
    }


  /* Check anonymous struct/anonymous union fields.  */
  finish_struct_anon (t);

  /* We've built up the list of access declarations in reverse order.
     Fix that now.  */
  *access_decls = nreverse (*access_decls);
}

/* Return a FIELD_DECL for a pointer-to-virtual-table or
   pointer-to-virtual-base.  The NAME, ASSEMBLER_NAME, and TYPE of the
   field are as indicated.  The CLASS_TYPE in which this field occurs
   is also indicated.  *EMPTY_P is set to a non-zero value by this
   function to indicate that a class containing this field is
   non-empty.  */

static tree
build_vtbl_or_vbase_field (name, assembler_name, type, class_type, 
			   empty_p)
     tree name;
     tree assembler_name;
     tree type;
     tree class_type;
     int *empty_p;
{
  tree field;

  /* This class is non-empty.  */
  *empty_p = 0;

  /* Build the FIELD_DECL.  */
  field = build_lang_decl (FIELD_DECL, name, type);
  DECL_ASSEMBLER_NAME (field) = assembler_name;
  DECL_VIRTUAL_P (field) = 1;
  DECL_ARTIFICIAL (field) = 1;
  DECL_FIELD_CONTEXT (field) = class_type;
  DECL_CLASS_CONTEXT (field) = class_type;
  DECL_FCONTEXT (field) = class_type;
  DECL_SAVED_INSNS (field) = 0;
  DECL_FIELD_SIZE (field) = 0;
  DECL_ALIGN (field) = TYPE_ALIGN (type);

  /* Return it.  */
  return field;
}

/* Returns list of virtual base class pointers in a FIELD_DECL chain.  */

static tree
build_vbase_pointer_fields (rec, empty_p)
     tree rec;
     int *empty_p;
{
  /* Chain to hold all the new FIELD_DECLs which point at virtual
     base classes.  */
  tree vbase_decls = NULL_TREE;
  tree binfos = TYPE_BINFO_BASETYPES (rec);
  int n_baseclasses = CLASSTYPE_N_BASECLASSES (rec);
  tree decl;
  int i;

  /* Handle basetypes almost like fields, but record their
     offsets differently.  */

  for (i = 0; i < n_baseclasses; i++)
    {
      register tree base_binfo = TREE_VEC_ELT (binfos, i);
      register tree basetype = BINFO_TYPE (base_binfo);

      if (TYPE_SIZE (basetype) == 0)
	/* This error is now reported in xref_tag, thus giving better
	   location information.  */
	continue;

      /* All basetypes are recorded in the association list of the
	 derived type.  */

      if (TREE_VIA_VIRTUAL (base_binfo))
	{
	  int j;
	  const char *name;

	  /* The offset for a virtual base class is only used in computing
	     virtual function tables and for initializing virtual base
	     pointers.  It is built once `get_vbase_types' is called.  */

	  /* If this basetype can come from another vbase pointer
	     without an additional indirection, we will share
	     that pointer.  If an indirection is involved, we
	     make our own pointer.  */
	  for (j = 0; j < n_baseclasses; j++)
	    {
	      tree other_base_binfo = TREE_VEC_ELT (binfos, j);
	      if (! TREE_VIA_VIRTUAL (other_base_binfo)
		  && BINFO_FOR_VBASE (basetype, BINFO_TYPE (other_base_binfo)))
		goto got_it;
	    }
	  FORMAT_VBASE_NAME (name, basetype);
	  decl = build_vtbl_or_vbase_field (get_identifier (name), 
					    get_identifier (VTABLE_BASE),
					    build_pointer_type (basetype),
					    rec,
					    empty_p);
	  BINFO_VPTR_FIELD (base_binfo) = decl;
	  TREE_CHAIN (decl) = vbase_decls;
	  vbase_decls = decl;
	  *empty_p = 0;

	got_it:
	  /* The space this decl occupies has already been accounted for.  */
	  ;
	}
    }

  return vbase_decls;
}

/* If the empty base field in DECL overlaps with a base of the same type in
   NEWDECL, which is either another base field or the first data field of
   the class, pad the base just before NEWDECL and return 1.  Otherwise,
   return 0.  */

static int
avoid_overlap (decl, newdecl, empty_p)
     tree decl, newdecl;
     int *empty_p;
{
  tree field;

  if (newdecl == NULL_TREE
      || ! types_overlap_p (TREE_TYPE (decl), TREE_TYPE (newdecl)))
    return 0;

  for (field = decl; TREE_CHAIN (field) && TREE_CHAIN (field) != newdecl;
       field = TREE_CHAIN (field))
    ;

  DECL_SIZE (field) = integer_one_node;
  /* The containing class cannot be empty; this field takes up space.  */
  *empty_p = 0;

  return 1;
}

/* Returns a list of fields to stand in for the base class subobjects
   of REC.  These fields are later removed by layout_basetypes.  */

static tree
build_base_fields (rec, empty_p)
     tree rec;
     int *empty_p;
{
  /* Chain to hold all the new FIELD_DECLs which stand in for base class
     subobjects.  */
  tree base_decls = NULL_TREE;
  tree binfos = TYPE_BINFO_BASETYPES (rec);
  int n_baseclasses = CLASSTYPE_N_BASECLASSES (rec);
  tree decl, nextdecl;
  int i, saw_empty = 0;
  unsigned int base_align = 0;

  for (i = 0; i < n_baseclasses; ++i)
    {
      register tree base_binfo = TREE_VEC_ELT (binfos, i);
      register tree basetype = BINFO_TYPE (base_binfo);

      if (TYPE_SIZE (basetype) == 0)
	/* This error is now reported in xref_tag, thus giving better
	   location information.  */
	continue;

      if (TREE_VIA_VIRTUAL (base_binfo))
	continue;

      decl = build_lang_decl (FIELD_DECL, NULL_TREE, basetype);
      DECL_ARTIFICIAL (decl) = 1;
      DECL_FIELD_CONTEXT (decl) = DECL_CLASS_CONTEXT (decl) = rec;
      DECL_SIZE (decl) = CLASSTYPE_SIZE (basetype);
      DECL_ALIGN (decl) = CLASSTYPE_ALIGN (basetype);
      TREE_CHAIN (decl) = base_decls;
      base_decls = decl;

      if (flag_new_abi && DECL_SIZE (decl) == integer_zero_node)
	saw_empty = 1;
      else
	{
	  /* The containing class is non-empty because it has a
	     non-empty base class.  */
	  *empty_p = 0;

	  if (! flag_new_abi)
	    {
	      /* Brain damage for backwards compatibility.  For no
		 good reason, the old layout_basetypes made every base
		 at least as large as the alignment for the bases up
		 to that point, gratuitously wasting space.  So we do
		 the same thing here.  */
	      base_align = MAX (base_align, DECL_ALIGN (decl));
	      DECL_SIZE (decl)
		= size_int (MAX (TREE_INT_CST_LOW (DECL_SIZE (decl)),
				 (int) base_align));
	    }
	}
    }

  /* Reverse the list of fields so we allocate the bases in the proper
     order.  */
  base_decls = nreverse (base_decls);

  /* In the presence of empty base classes, we run the risk of allocating
     two objects of the same class on top of one another.  Avoid that.  */
  if (flag_new_abi && saw_empty)
    for (decl = base_decls; decl; decl = TREE_CHAIN (decl))
      {
	if (DECL_SIZE (decl) == integer_zero_node)
	  {
	    /* First step through the following bases until we find
	       an overlap or a non-empty base.  */
	    for (nextdecl = TREE_CHAIN (decl); nextdecl;
		 nextdecl = TREE_CHAIN (nextdecl))
	      {
		if (avoid_overlap (decl, nextdecl, empty_p)
		    || DECL_SIZE (nextdecl) != integer_zero_node)
		  goto nextbase;
	      }

	    /* If we're still looking, also check against the first
	       field.  */
	    for (nextdecl = TYPE_FIELDS (rec);
		 nextdecl && TREE_CODE (nextdecl) != FIELD_DECL;
		 nextdecl = TREE_CHAIN (nextdecl))
	      /* keep looking */;
	    avoid_overlap (decl, nextdecl, empty_p);
	  }
      nextbase:;
      }

  return base_decls;
}

/* Go through the TYPE_METHODS of T issuing any appropriate
   diagnostics, figuring out which methods override which other
   methods, and so forth.  */

static void
check_methods (t)
     tree t;
{
  tree x;

  for (x = TYPE_METHODS (t); x; x = TREE_CHAIN (x))
    {
      GNU_xref_member (current_class_name, x);

      /* If this was an evil function, don't keep it in class.  */
      if (IDENTIFIER_ERROR_LOCUS (DECL_ASSEMBLER_NAME (x)))
	continue;

      /* Do both of these, even though they're in the same union;
	 if the insn `r' member and the size `i' member are
	 different sizes, as on the alpha, the larger of the two
	 will end up with garbage in it.  */
      DECL_SAVED_INSNS (x) = 0;
      DECL_FIELD_SIZE (x) = 0;

      check_for_override (x, t);
      if (DECL_PURE_VIRTUAL_P (x) && ! DECL_VINDEX (x))
	cp_error_at ("initializer specified for non-virtual method `%D'", x);

      /* The name of the field is the original field name
	 Save this in auxiliary field for later overloading.  */
      if (DECL_VINDEX (x))
	{
	  TYPE_POLYMORPHIC_P (t) = 1;
	  if (DECL_PURE_VIRTUAL_P (x))
	    CLASSTYPE_PURE_VIRTUALS (t)
	      = tree_cons (NULL_TREE, x, CLASSTYPE_PURE_VIRTUALS (t));
	}
    }
}

/* Remove all zero-width bit-fields from T.  */

static void
remove_zero_width_bit_fields (t)
     tree t;
{
  tree *fieldsp;

  fieldsp = &TYPE_FIELDS (t); 
  while (*fieldsp)
    {
      if (TREE_CODE (*fieldsp) == FIELD_DECL
	  && DECL_C_BIT_FIELD (*fieldsp) 
	  && DECL_INITIAL (*fieldsp))
	*fieldsp = TREE_CHAIN (*fieldsp);
      else
	fieldsp = &TREE_CHAIN (*fieldsp);
    }
}

/* Check the validity of the bases and members declared in T.  Add any
   implicitly-generated functions (like copy-constructors and
   assignment operators).  Compute various flag bits (like
   CLASSTYPE_NON_POD_T) for T.  This routine works purely at the C++
   level: i.e., independently of the ABI in use.  */

static void
check_bases_and_members (t, empty_p)
     tree t;
     int *empty_p;
{
  /* Nonzero if we are not allowed to generate a default constructor
     for this case.  */
  int cant_have_default_ctor;
  /* Nonzero if the implicitly generated copy constructor should take
     a non-const reference argument.  */
  int cant_have_const_ctor;
  /* Nonzero if the the implicitly generated assignment operator
     should take a non-const reference argument.  */
  int no_const_asn_ref;
  tree access_decls;

  /* By default, we use const reference arguments and generate default
     constructors.  */
  cant_have_default_ctor = 0;
  cant_have_const_ctor = 0;
  no_const_asn_ref = 0;

  /* Assume that the class is nearly empty; we'll clear this flag if
     it turns out not to be nearly empty.  */
  CLASSTYPE_NEARLY_EMPTY_P (t) = 1;

  /* Check all the base-classes. */
  check_bases (t, &cant_have_default_ctor, &cant_have_const_ctor,
	       &no_const_asn_ref);

  /* Check all the data member declarations.  */
  check_field_decls (t, &access_decls, empty_p,
		     &cant_have_default_ctor,
		     &cant_have_const_ctor,
		     &no_const_asn_ref);

  /* Check all the method declarations.  */
  check_methods (t);

  /* A nearly-empty class has to be polymorphic; a nearly empty class
     contains a vptr.  */
  if (!TYPE_POLYMORPHIC_P (t))
    CLASSTYPE_NEARLY_EMPTY_P (t) = 0;

  /* Do some bookkeeping that will guide the generation of implicitly
     declared member functions.  */
  TYPE_HAS_COMPLEX_INIT_REF (t)
    |= (TYPE_HAS_INIT_REF (t) 
	|| TYPE_USES_VIRTUAL_BASECLASSES (t)
	|| TYPE_POLYMORPHIC_P (t));
  TYPE_NEEDS_CONSTRUCTING (t)
    |= (TYPE_HAS_CONSTRUCTOR (t) 
	|| TYPE_USES_VIRTUAL_BASECLASSES (t)
	|| TYPE_POLYMORPHIC_P (t));
  CLASSTYPE_NON_AGGREGATE (t) |= (TYPE_HAS_CONSTRUCTOR (t)
				  || TYPE_POLYMORPHIC_P (t));
  CLASSTYPE_NON_POD_P (t)
    |= (CLASSTYPE_NON_AGGREGATE (t) || TYPE_HAS_DESTRUCTOR (t) 
	|| TYPE_HAS_ASSIGN_REF (t));
  TYPE_HAS_REAL_ASSIGN_REF (t) |= TYPE_HAS_ASSIGN_REF (t);
  TYPE_HAS_COMPLEX_ASSIGN_REF (t)
    |= TYPE_HAS_ASSIGN_REF (t) || TYPE_USES_VIRTUAL_BASECLASSES (t);

  /* Synthesize any needed methods.  Note that methods will be synthesized
     for anonymous unions; grok_x_components undoes that.  */
  add_implicitly_declared_members (t, cant_have_default_ctor,
				   cant_have_const_ctor,
				   no_const_asn_ref);

  /* Build and sort the CLASSTYPE_METHOD_VEC.  */
  finish_struct_methods (t);

  /* Process the access-declarations.  We wait until now to do this
     because handle_using_decls requires that the CLASSTYPE_METHOD_VEC
     be set up correctly.  */
  while (access_decls)
    {
      handle_using_decl (TREE_VALUE (access_decls), t);
      access_decls = TREE_CHAIN (access_decls);
    }
}

/* If T needs a pointer to its virtual function table, set TYPE_VFIELD
   accordingly, and, if necessary, add the TYPE_VFIELD to the
   TYPE_FIELDS list.  */

static void
create_vtable_ptr (t, empty_p, has_virtual_p, max_has_virtual_p,
		   pending_virtuals_p, pending_hard_virtuals_p)
     tree t;
     int *empty_p;
     int *has_virtual_p;
     int *max_has_virtual_p;
     tree *pending_virtuals_p;
     tree *pending_hard_virtuals_p;
{
  tree fn;

  /* If possible, we reuse the virtual function table pointer from one
     of our base classes.  */
  if (CLASSTYPE_N_BASECLASSES (t))
    {
      struct base_info base_info;

      /* Remember where we got our vfield from.  */
      CLASSTYPE_VFIELD_PARENT (t) = finish_base_struct (t, &base_info);
      *has_virtual_p = base_info.has_virtual;
      *max_has_virtual_p = base_info.max_has_virtual;
      TYPE_VFIELD (t) = base_info.vfield;
      CLASSTYPE_VFIELDS (t) = base_info.vfields;
      CLASSTYPE_RTTI (t) = base_info.rtti;
    }

  /* Loop over the virtual functions, adding them to our various
     vtables.  */
  for (fn = TYPE_METHODS (t); fn; fn = TREE_CHAIN (fn))
    if (DECL_VINDEX (fn))
      add_virtual_function (pending_virtuals_p, pending_hard_virtuals_p,
			    has_virtual_p, fn, t);

  /* If we couldn't find an appropriate base class, create a new field
     here.  */
  if (*has_virtual_p && !TYPE_VFIELD (t))
    {
      /* We build this decl with vtbl_ptr_type_node, which is a
	 `vtable_entry_type*'.  It might seem more precise to use
	 `vtable_entry_type (*)[N]' where N is the number of firtual
	 functions.  However, that would require the vtable pointer in
	 base classes to have a different type than the vtable pointer
	 in derived classes.  We could make that happen, but that
	 still wouldn't solve all the problems.  In particular, the
	 type-based alias analysis code would decide that assignments
	 to the base class vtable pointer can't alias assignments to
	 the derived class vtable pointer, since they have different
	 types.  Thus, in an derived class destructor, where the base
	 class constructor was inlined, we could generate bad code for
	 setting up the vtable pointer.  

         Therefore, we use one type for all vtable pointers.  We still
	 use a type-correct type; it's just doesn't indicate the array
	 bounds.  That's better than using `void*' or some such; it's
	 cleaner, and it let's the alias analysis code know that these
	 stores cannot alias stores to void*!  */
      TYPE_VFIELD (t) 
	= build_vtbl_or_vbase_field (get_vfield_name (t),
				     get_identifier (VFIELD_BASE),
				     vtbl_ptr_type_node,
				     t,
				     empty_p);

      /* Add the new field to the list of fields in this class.  */
      if (!flag_new_abi)
	/* In the old ABI, the vtable pointer goes at the end of the
	   class.  */
	TYPE_FIELDS (t) = chainon (TYPE_FIELDS (t), TYPE_VFIELD (t));
      else
	{
	  /* But in the new ABI, the vtable pointer is the first thing
	     in the class.  */
	  TYPE_FIELDS (t) = chainon (TYPE_VFIELD (t), TYPE_FIELDS (t));
	  /* If there were any baseclasses, they can't possibly be at
	     offset zero any more, because that's where the vtable
	     pointer is.  So, converting to a base class is going to
	     take work.  */
	  if (CLASSTYPE_N_BASECLASSES (t))
	    TYPE_BASE_CONVS_MAY_REQUIRE_CODE_P (t) = 1;
	}

      /* We can't yet add this new field to the list of all virtual
	 function table pointers in this class.  The
	 modify_all_vtables function depends on this not being done.
	 So, it is done later, in finish_struct_1.  */
    }
}

/* Fixup the inline function given by INFO now that the class is
   complete.  */

static void
fixup_pending_inline (info)
     struct pending_inline *info;
{
  if (info)
    {
      tree args;
      tree fn = info->fndecl;

      args = DECL_ARGUMENTS (fn);
      while (args)
	{
	  DECL_CONTEXT (args) = fn;
	  args = TREE_CHAIN (args);
	}
    }
}

/* Fixup the inline methods and friends in TYPE now that TYPE is
   complete.  */

static void
fixup_inline_methods (type)
     tree type;
{
  tree method = TYPE_METHODS (type);

  if (method && TREE_CODE (method) == TREE_VEC)
    {
      if (TREE_VEC_ELT (method, 1))
	method = TREE_VEC_ELT (method, 1);
      else if (TREE_VEC_ELT (method, 0))
	method = TREE_VEC_ELT (method, 0);
      else
	method = TREE_VEC_ELT (method, 2);
    }

  /* Do inline member functions.  */
  for (; method; method = TREE_CHAIN (method))
    fixup_pending_inline (DECL_PENDING_INLINE_INFO (method));

  /* Do friends.  */
  for (method = CLASSTYPE_INLINE_FRIENDS (type); 
       method; 
       method = TREE_CHAIN (method))
    fixup_pending_inline (DECL_PENDING_INLINE_INFO (TREE_VALUE (method)));
  CLASSTYPE_INLINE_FRIENDS (type) = NULL_TREE;
}

/* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T.  Calculate
   BINFO_OFFSETs for all of the base-classes.  Position the vtable
   pointer.  */

static void
layout_class_type (t, empty_p, has_virtual_p, max_has_virtual_p,
		   pending_virtuals_p, pending_hard_virtuals_p)
     tree t;
     int *empty_p;
     int *has_virtual_p;
     int *max_has_virtual_p;
     tree *pending_virtuals_p;
     tree *pending_hard_virtuals_p;
{
  /* Add pointers to all of our virtual base-classes.  */
  TYPE_FIELDS (t) = chainon (build_vbase_pointer_fields (t, empty_p),
			     TYPE_FIELDS (t));
  /* Build FIELD_DECLs for all of the non-virtual base-types.  */
  TYPE_FIELDS (t) = chainon (build_base_fields (t, empty_p), 
			     TYPE_FIELDS (t));

  /* Create a pointer to our virtual function table.  */
  create_vtable_ptr (t, empty_p, has_virtual_p, max_has_virtual_p,
		     pending_virtuals_p, pending_hard_virtuals_p);

  /* CLASSTYPE_INLINE_FRIENDS is really TYPE_NONCOPIED_PARTS.  Thus,
     we have to save this before we start modifying
     TYPE_NONCOPIED_PARTS.  */
  fixup_inline_methods (t);

  /* We make all structures have at least one element, so that they
     have non-zero size.  The field that we add here is fake, in the
     sense that, for example, we don't want people to be able to
     initialize it later.  So, we add it just long enough to let the
     back-end lay out the type, and then remove it.  */
  if (*empty_p)
    {
      tree decl = build_lang_decl
	(FIELD_DECL, NULL_TREE, char_type_node);
      TREE_CHAIN (decl) = TYPE_FIELDS (t);
      TYPE_FIELDS (t) = decl;
      TYPE_NONCOPIED_PARTS (t) 
	= tree_cons (NULL_TREE, decl, TYPE_NONCOPIED_PARTS (t));
      TREE_STATIC (TYPE_NONCOPIED_PARTS (t)) = 1;
    }

  /* Let the back-end lay out the type. Note that at this point we
     have only included non-virtual base-classes; we will lay out the
     virtual base classes later.  So, the TYPE_SIZE/TYPE_ALIGN after
     this call are not necessarily correct; they are just the size and
     alignment when no virtual base clases are used.  */
  layout_type (t);

  /* If we added an extra field to make this class non-empty, remove
     it now.  */
  if (*empty_p)
    TYPE_FIELDS (t) = TREE_CHAIN (TYPE_FIELDS (t));

  /* Delete all zero-width bit-fields from the list of fields.  Now
     that the type is laid out they are no longer important.  */
  remove_zero_width_bit_fields (t);

  /* Remember the size and alignment of the class before adding
     the virtual bases.  */
  if (*empty_p && flag_new_abi)
    CLASSTYPE_SIZE (t) = integer_zero_node;
  else if (flag_new_abi && TYPE_HAS_COMPLEX_INIT_REF (t)
	   && TYPE_HAS_COMPLEX_ASSIGN_REF (t))
    CLASSTYPE_SIZE (t) = TYPE_BINFO_SIZE (t);
  else
    CLASSTYPE_SIZE (t) = TYPE_SIZE (t);
  CLASSTYPE_ALIGN (t) = TYPE_ALIGN (t);

  /* Set the TYPE_DECL for this type to contain the right
     value for DECL_OFFSET, so that we can use it as part
     of a COMPONENT_REF for multiple inheritance.  */
  layout_decl (TYPE_MAIN_DECL (t), 0);

  /* Now fix up any virtual base class types that we left lying
     around.  We must get these done before we try to lay out the
     virtual function table.  */
  if (CLASSTYPE_N_BASECLASSES (t))
    /* layout_basetypes will remove the base subobject fields.  */
    *max_has_virtual_p = layout_basetypes (t, *max_has_virtual_p);
}
     
/* Create a RECORD_TYPE or UNION_TYPE node for a C struct or union declaration
   (or C++ class declaration).

   For C++, we must handle the building of derived classes.
   Also, C++ allows static class members.  The way that this is
   handled is to keep the field name where it is (as the DECL_NAME
   of the field), and place the overloaded decl in the DECL_FIELD_BITPOS
   of the field.  layout_record and layout_union will know about this.

   More C++ hair: inline functions have text in their
   DECL_PENDING_INLINE_INFO nodes which must somehow be parsed into
   meaningful tree structure.  After the struct has been laid out, set
   things up so that this can happen.

   And still more: virtual functions.  In the case of single inheritance,
   when a new virtual function is seen which redefines a virtual function
   from the base class, the new virtual function is placed into
   the virtual function table at exactly the same address that
   it had in the base class.  When this is extended to multiple
   inheritance, the same thing happens, except that multiple virtual
   function tables must be maintained.  The first virtual function
   table is treated in exactly the same way as in the case of single
   inheritance.  Additional virtual function tables have different
   DELTAs, which tell how to adjust `this' to point to the right thing.

   ATTRIBUTES is the set of decl attributes to be applied, if any.  */

void
finish_struct_1 (t)
     tree t;
{
  tree x;
  int has_virtual;
  int max_has_virtual;
  tree pending_virtuals = NULL_TREE;
  tree pending_hard_virtuals = NULL_TREE;
  int n_fields = 0;
  tree vfield;
  int n_baseclasses;
  int empty = 1;

  if (TYPE_SIZE (t))
    {
      if (IS_AGGR_TYPE (t))
	cp_error ("redefinition of `%#T'", t);
      else
	my_friendly_abort (172);
      popclass ();
      return;
    }

  GNU_xref_decl (current_function_decl, t);

  /* If this type was previously laid out as a forward reference,
     make sure we lay it out again.  */

  TYPE_SIZE (t) = NULL_TREE;
  CLASSTYPE_GOT_SEMICOLON (t) = 0;

  CLASSTYPE_VFIELD_PARENT (t) = -1;
  has_virtual = 0;
  max_has_virtual = 0;
  CLASSTYPE_RTTI (t) = NULL_TREE;
  n_baseclasses = CLASSTYPE_N_BASECLASSES (t);

  /* Do end-of-class semantic processing: checking the validity of the
     bases and members and adding implicitly generated methods.  */
  check_bases_and_members (t, &empty);

  /* Layout the class itself.  */
  layout_class_type (t, &empty, &has_virtual, &max_has_virtual,
		     &pending_virtuals, &pending_hard_virtuals);

  if (TYPE_USES_VIRTUAL_BASECLASSES (t))
    {
      tree vbases;

      vbases = CLASSTYPE_VBASECLASSES (t);

      {
	/* Now fixup overrides of all functions in vtables from all
	   direct or indirect virtual base classes.  */
	tree binfos = BINFO_BASETYPES (TYPE_BINFO (t));
	int i, n_baseclasses = binfos ? TREE_VEC_LENGTH (binfos) : 0;

	for (i = 0; i < n_baseclasses; i++)
	  {
	    tree base_binfo = TREE_VEC_ELT (binfos, i);
	    tree basetype = BINFO_TYPE (base_binfo);
	    tree vbases;

	    vbases = CLASSTYPE_VBASECLASSES (basetype);
	    while (vbases)
	      {
		merge_overrides (binfo_member (BINFO_TYPE (vbases),
					       CLASSTYPE_VBASECLASSES (t)),
				 vbases, 1, t);
		vbases = TREE_CHAIN (vbases);
	      }
	  }
	}
    }

  /* Set up the DECL_FIELD_BITPOS of the vfield if we need to, as we
     might need to know it for setting up the offsets in the vtable
     (or in thunks) below.  */
  vfield = TYPE_VFIELD (t);
  if (vfield != NULL_TREE
      && DECL_FIELD_CONTEXT (vfield) != t)
    {
      tree binfo = get_binfo (DECL_FIELD_CONTEXT (vfield), t, 0);
      tree offset = BINFO_OFFSET (binfo);

      vfield = copy_node (vfield);
      copy_lang_decl (vfield);

      if (! integer_zerop (offset))
	offset = size_binop (MULT_EXPR, offset, size_int (BITS_PER_UNIT));
      DECL_FIELD_CONTEXT (vfield) = t;
      DECL_CLASS_CONTEXT (vfield) = t;
      DECL_FIELD_BITPOS (vfield)
	= size_binop (PLUS_EXPR, offset, DECL_FIELD_BITPOS (vfield));
      TYPE_VFIELD (t) = vfield;
    }

  if (has_virtual > max_has_virtual)
    max_has_virtual = has_virtual;
  if (max_has_virtual > 0)
    TYPE_POLYMORPHIC_P (t) = 1;

  if (flag_rtti && TYPE_POLYMORPHIC_P (t) && !pending_hard_virtuals)
    modify_all_vtables (t, NULL_TREE);

  for (pending_hard_virtuals = nreverse (pending_hard_virtuals);
       pending_hard_virtuals;
       pending_hard_virtuals = TREE_CHAIN (pending_hard_virtuals))
    modify_all_vtables (t, TREE_VALUE (pending_hard_virtuals));
  
  if (TYPE_USES_VIRTUAL_BASECLASSES (t))
    {
      tree vbases;
      /* Now fixup any virtual function entries from virtual bases
	 that have different deltas.  This has to come after we do the
	 pending hard virtuals, as we might have a function that comes
	 from multiple virtual base instances that is only overridden
	 by a hard virtual above.  */
      vbases = CLASSTYPE_VBASECLASSES (t);
      while (vbases)
	{
	  /* We might be able to shorten the amount of work we do by
	     only doing this for vtables that come from virtual bases
	     that have differing offsets, but don't want to miss any
	     entries.  */
	  fixup_vtable_deltas (vbases, 1, t);
	  vbases = TREE_CHAIN (vbases);
	}
    }

  /* Under our model of GC, every C++ class gets its own virtual
     function table, at least virtually.  */
  if (pending_virtuals)
    {
      pending_virtuals = nreverse (pending_virtuals);
      /* We must enter these virtuals into the table.  */
      if (!CLASSTYPE_HAS_PRIMARY_BASE_P (t))
	{
	  if (! CLASSTYPE_COM_INTERFACE (t))
	    {
	      /* The second slot is for the tdesc pointer when thunks are used.  */
	      if (flag_vtable_thunks)
		pending_virtuals = tree_cons (NULL_TREE, NULL_TREE, pending_virtuals);

	      /* The first slot is for the rtti offset.  */
	      pending_virtuals = tree_cons (NULL_TREE, NULL_TREE, pending_virtuals);

	      set_rtti_entry (pending_virtuals,
			      convert (ssizetype, integer_zero_node), t);
	    }
	  build_vtable (NULL_TREE, t);
	}
      else
	{
	  /* Here we know enough to change the type of our virtual
	     function table, but we will wait until later this function.  */

	  if (! BINFO_NEW_VTABLE_MARKED (TYPE_BINFO (t)))
	    build_vtable (CLASSTYPE_PRIMARY_BINFO (t), t);
	}

      /* If this type has basetypes with constructors, then those
	 constructors might clobber the virtual function table.  But
	 they don't if the derived class shares the exact vtable of the base
	 class.  */

      CLASSTYPE_NEEDS_VIRTUAL_REINIT (t) = 1;
    }
  else if (CLASSTYPE_HAS_PRIMARY_BASE_P (t))
    {
      tree binfo = CLASSTYPE_PRIMARY_BINFO (t);

      /* This class contributes nothing new to the virtual function
	 table.  However, it may have declared functions which
	 went into the virtual function table "inherited" from the
	 base class.  If so, we grab a copy of those updated functions,
	 and pretend they are ours.  */

      /* See if we should steal the virtual info from base class.  */
      if (TYPE_BINFO_VTABLE (t) == NULL_TREE)
	TYPE_BINFO_VTABLE (t) = BINFO_VTABLE (binfo);
      if (TYPE_BINFO_VIRTUALS (t) == NULL_TREE)
	TYPE_BINFO_VIRTUALS (t) = BINFO_VIRTUALS (binfo);
      if (TYPE_BINFO_VTABLE (t) != BINFO_VTABLE (binfo))
	CLASSTYPE_NEEDS_VIRTUAL_REINIT (t) = 1;
    }

  if (max_has_virtual || CLASSTYPE_HAS_PRIMARY_BASE_P (t))
    {
      CLASSTYPE_VSIZE (t) = has_virtual;
      if (CLASSTYPE_HAS_PRIMARY_BASE_P (t))
	{
	  if (pending_virtuals)
	    TYPE_BINFO_VIRTUALS (t) = chainon (TYPE_BINFO_VIRTUALS (t),
						pending_virtuals);
	}
      else if (has_virtual)
	{
	  TYPE_BINFO_VIRTUALS (t) = pending_virtuals;
	  DECL_VIRTUAL_P (TYPE_BINFO_VTABLE (t)) = 1;
	}
    }

  /* Now lay out the virtual function table.  */
  if (has_virtual)
    {
      /* Use size_int so values are memoized in common cases.  */
      tree itype = build_index_type (size_int (has_virtual));
      tree atype = build_cplus_array_type (vtable_entry_type, itype);

      layout_type (atype);

      /* We may have to grow the vtable.  */
      if (TREE_TYPE (TYPE_BINFO_VTABLE (t)) != atype)
	{
	  TREE_TYPE (TYPE_BINFO_VTABLE (t)) = atype;
	  DECL_SIZE (TYPE_BINFO_VTABLE (t)) = 0;
	  layout_decl (TYPE_BINFO_VTABLE (t), 0);
	  /* At one time the vtable info was grabbed 2 words at a time.  This
	     fails on sparc unless you have 8-byte alignment.  (tiemann) */
	  DECL_ALIGN (TYPE_BINFO_VTABLE (t))
	    = MAX (TYPE_ALIGN (double_type_node),
		   DECL_ALIGN (TYPE_BINFO_VTABLE (t)));
	}
    }

  /* If we created a new vtbl pointer for this class, add it to the
     list.  */
  if (TYPE_VFIELD (t) && CLASSTYPE_VFIELD_PARENT (t) == -1)
    CLASSTYPE_VFIELDS (t) 
      = chainon (CLASSTYPE_VFIELDS (t), build_tree_list (NULL_TREE, t));

  finish_struct_bits (t, max_has_virtual);

  /* Complete the rtl for any static member objects of the type we're
     working on.  */
  for (x = TYPE_FIELDS (t); x; x = TREE_CHAIN (x))
    {
      if (TREE_CODE (x) == VAR_DECL && TREE_STATIC (x)
	  && TREE_TYPE (x) == t)
	{
	  DECL_MODE (x) = TYPE_MODE (t);
	  make_decl_rtl (x, NULL, 0);
	}
    }

  /* Done with FIELDS...now decide whether to sort these for
     faster lookups later.

     The C front-end only does this when n_fields > 15.  We use
     a smaller number because most searches fail (succeeding
     ultimately as the search bores through the inheritance
     hierarchy), and we want this failure to occur quickly.  */

  n_fields = count_fields (TYPE_FIELDS (t));
  if (n_fields > 7)
    {
      tree field_vec = make_tree_vec (n_fields);
      add_fields_to_vec (TYPE_FIELDS (t), field_vec, 0);
      qsort (&TREE_VEC_ELT (field_vec, 0), n_fields, sizeof (tree),
	     (int (*)(const void *, const void *))field_decl_cmp);
      if (! DECL_LANG_SPECIFIC (TYPE_MAIN_DECL (t)))
	retrofit_lang_decl (TYPE_MAIN_DECL (t));
      DECL_SORTED_FIELDS (TYPE_MAIN_DECL (t)) = field_vec;
    }

  if (TYPE_HAS_CONSTRUCTOR (t))
    {
      tree vfields = CLASSTYPE_VFIELDS (t);

      while (vfields)
	{
	  /* Mark the fact that constructor for T
	     could affect anybody inheriting from T
	     who wants to initialize vtables for VFIELDS's type.  */
	  if (VF_DERIVED_VALUE (vfields))
	    TREE_ADDRESSABLE (vfields) = 1;
	  vfields = TREE_CHAIN (vfields);
	}
    }

  if (CLASSTYPE_VSIZE (t) != 0)
    {
      /* In addition to this one, all the other vfields should be listed.  */
      /* Before that can be done, we have to have FIELD_DECLs for them, and
	 a place to find them.  */
      TYPE_NONCOPIED_PARTS (t) 
	= tree_cons (default_conversion (TYPE_BINFO_VTABLE (t)),
		     TYPE_VFIELD (t), TYPE_NONCOPIED_PARTS (t));

      if (warn_nonvdtor && TYPE_HAS_DESTRUCTOR (t)
	  && DECL_VINDEX (TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (t), 1)) == NULL_TREE)
	cp_warning ("`%#T' has virtual functions but non-virtual destructor",
		    t);
    }

  /* Make the rtl for any new vtables we have created, and unmark
     the base types we marked.  */
  finish_vtbls (TYPE_BINFO (t), 1, t);
  hack_incomplete_structures (t);

  if (warn_overloaded_virtual)
    warn_hidden (t);

  maybe_suppress_debug_info (t);

  /* Finish debugging output for this type.  */
  rest_of_type_compilation (t, toplevel_bindings_p ());
}

/* When T was built up, the member declarations were added in reverse
   order.  Rearrange them to declaration order.  */

void
unreverse_member_declarations (t)
     tree t;
{
  tree next;
  tree prev;
  tree x;

  /* The TYPE_FIELDS, TYPE_METHODS, and CLASSTYPE_TAGS are all in
     reverse order.  Put them in declaration order now.  */
  TYPE_METHODS (t) = nreverse (TYPE_METHODS (t));
  CLASSTYPE_TAGS (t) = nreverse (CLASSTYPE_TAGS (t));

  /* Actually, for the TYPE_FIELDS, only the non TYPE_DECLs are in
     reverse order, so we can't just use nreverse.  */
  prev = NULL_TREE;
  for (x = TYPE_FIELDS (t); 
       x && TREE_CODE (x) != TYPE_DECL; 
       x = next)
    {
      next = TREE_CHAIN (x);
      TREE_CHAIN (x) = prev;
      prev = x;
    }
  if (prev)
    {
      TREE_CHAIN (TYPE_FIELDS (t)) = x;
      if (prev)
	TYPE_FIELDS (t) = prev;
    }
}

tree
finish_struct (t, attributes)
     tree t, attributes;
{
  /* Now that we've got all the field declarations, reverse everything
     as necessary.  */
  unreverse_member_declarations (t);

  cplus_decl_attributes (t, attributes, NULL_TREE);

  if (processing_template_decl)
    {
      finish_struct_methods (t);
      TYPE_SIZE (t) = integer_zero_node;
    }
  else
    finish_struct_1 (t);

  TYPE_BEING_DEFINED (t) = 0;

  if (current_class_type)
    popclass ();
  else
    error ("trying to finish struct, but kicked out due to previous parse errors.");

  if (processing_template_decl)
    {
      tree scope = current_scope ();
      if (scope && TREE_CODE (scope) == FUNCTION_DECL)
	add_tree (build_min (TAG_DEFN, t));
    }

  return t;
}
\f
/* Return the dynamic type of INSTANCE, if known.
   Used to determine whether the virtual function table is needed
   or not.

   *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
   of our knowledge of its type.  */

static tree
fixed_type_or_null (instance, nonnull)
     tree instance;
     int *nonnull;
{
  if (nonnull)
    *nonnull = 0;

  switch (TREE_CODE (instance))
    {
    case INDIRECT_REF:
      /* Check that we are not going through a cast of some sort.  */
      if (TREE_TYPE (instance)
	  == TREE_TYPE (TREE_TYPE (TREE_OPERAND (instance, 0))))
	instance = TREE_OPERAND (instance, 0);
      /* fall through...  */
    case CALL_EXPR:
      /* This is a call to a constructor, hence it's never zero.  */
      if (TREE_HAS_CONSTRUCTOR (instance))
	{
	  if (nonnull)
	    *nonnull = 1;
	  return TREE_TYPE (instance);
	}
      return NULL_TREE;

    case SAVE_EXPR:
      /* This is a call to a constructor, hence it's never zero.  */
      if (TREE_HAS_CONSTRUCTOR (instance))
	{
	  if (nonnull)
	    *nonnull = 1;
	  return TREE_TYPE (instance);
	}
      return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull);

    case RTL_EXPR:
      return NULL_TREE;

    case PLUS_EXPR:
    case MINUS_EXPR:
      if (TREE_CODE (TREE_OPERAND (instance, 1)) == INTEGER_CST)
	/* Propagate nonnull.  */
	fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull);
      if (TREE_CODE (TREE_OPERAND (instance, 0)) == ADDR_EXPR)
	return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull);
      return NULL_TREE;

    case NOP_EXPR:
    case CONVERT_EXPR:
      return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull);

    case ADDR_EXPR:
      if (nonnull)
	*nonnull = 1;
      return fixed_type_or_null (TREE_OPERAND (instance, 0), nonnull);

    case COMPONENT_REF:
      return fixed_type_or_null (TREE_OPERAND (instance, 1), nonnull);

    case VAR_DECL:
    case FIELD_DECL:
      if (TREE_CODE (TREE_TYPE (instance)) == ARRAY_TYPE
	  && IS_AGGR_TYPE (TREE_TYPE (TREE_TYPE (instance))))
	{
	  if (nonnull)
	    *nonnull = 1;
	  return TREE_TYPE (TREE_TYPE (instance));
	}
      /* fall through...  */
    case TARGET_EXPR:
    case PARM_DECL:
      if (IS_AGGR_TYPE (TREE_TYPE (instance)))
	{
	  if (nonnull)
	    *nonnull = 1;
	  return TREE_TYPE (instance);
	}
      else if (nonnull)
	{
	  if (instance == current_class_ptr
	      && flag_this_is_variable <= 0)
	    {
	      /* Normally, 'this' must be non-null.  */
	      if (flag_this_is_variable == 0)
		*nonnull = 1;

	      /* <0 means we're in a constructor and we know our type.  */
	      if (flag_this_is_variable < 0)
		return TREE_TYPE (TREE_TYPE (instance));
	    }
	  else if (TREE_CODE (TREE_TYPE (instance)) == REFERENCE_TYPE)
	    /* Reference variables should be references to objects.  */
	    *nonnull = 1;
	}
      return NULL_TREE;

    default:
      return NULL_TREE;
    }
}

/* Return non-zero if the dynamic type of INSTANCE is known, and equivalent
   to the static type.  We also handle the case where INSTANCE is really
   a pointer.

   Used to determine whether the virtual function table is needed
   or not.

   *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
   of our knowledge of its type.  */

int
resolves_to_fixed_type_p (instance, nonnull)
     tree instance;
     int *nonnull;
{
  tree t = TREE_TYPE (instance);
  tree fixed = fixed_type_or_null (instance, nonnull);
  if (fixed == NULL_TREE)
    return 0;
  if (POINTER_TYPE_P (t))
    t = TREE_TYPE (t);
  return same_type_p (TYPE_MAIN_VARIANT (t), TYPE_MAIN_VARIANT (fixed));
}

\f
void
init_class_processing ()
{
  current_class_depth = 0;
  current_class_stack_size = 10;
  current_class_stack 
    = (class_stack_node_t) xmalloc (current_class_stack_size 
				    * sizeof (struct class_stack_node));

  access_default_node = build_int_2 (0, 0);
  access_public_node = build_int_2 (1, 0);
  access_protected_node = build_int_2 (2, 0);
  access_private_node = build_int_2 (3, 0);
  access_default_virtual_node = build_int_2 (4, 0);
  access_public_virtual_node = build_int_2 (5, 0);
  access_protected_virtual_node = build_int_2 (6, 0);
  access_private_virtual_node = build_int_2 (7, 0);
}

/* Set current scope to NAME. CODE tells us if this is a
   STRUCT, UNION, or ENUM environment.

   NAME may end up being NULL_TREE if this is an anonymous or
   late-bound struct (as in "struct { ... } foo;")  */

/* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE to
   appropriate values, found by looking up the type definition of
   NAME (as a CODE).

   If MODIFY is 1, we set IDENTIFIER_CLASS_VALUE's of names
   which can be seen locally to the class.  They are shadowed by
   any subsequent local declaration (including parameter names).

   If MODIFY is 2, we set IDENTIFIER_CLASS_VALUE's of names
   which have static meaning (i.e., static members, static
   member functions, enum declarations, etc).

   If MODIFY is 3, we set IDENTIFIER_CLASS_VALUE of names
   which can be seen locally to the class (as in 1), but
   know that we are doing this for declaration purposes
   (i.e. friend foo::bar (int)).

   So that we may avoid calls to lookup_name, we cache the _TYPE
   nodes of local TYPE_DECLs in the TREE_TYPE field of the name.

   For multiple inheritance, we perform a two-pass depth-first search
   of the type lattice.  The first pass performs a pre-order search,
   marking types after the type has had its fields installed in
   the appropriate IDENTIFIER_CLASS_VALUE slot.  The second pass merely
   unmarks the marked types.  If a field or member function name
   appears in an ambiguous way, the IDENTIFIER_CLASS_VALUE of
   that name becomes `error_mark_node'.  */

void
pushclass (type, modify)
     tree type;
     int modify;
{
  type = TYPE_MAIN_VARIANT (type);

  /* Make sure there is enough room for the new entry on the stack.  */
  if (current_class_depth + 1 >= current_class_stack_size) 
    {
      current_class_stack_size *= 2;
      current_class_stack
	= (class_stack_node_t) xrealloc (current_class_stack,
					 current_class_stack_size
					 * sizeof (struct class_stack_node));
    }

  /* Insert a new entry on the class stack.  */
  current_class_stack[current_class_depth].name = current_class_name;
  current_class_stack[current_class_depth].type = current_class_type;
  current_class_stack[current_class_depth].access = current_access_specifier;
  current_class_stack[current_class_depth].names_used = 0;
  current_class_depth++;

  /* Now set up the new type.  */
  current_class_name = TYPE_NAME (type);
  if (TREE_CODE (current_class_name) == TYPE_DECL)
    current_class_name = DECL_NAME (current_class_name);
  current_class_type = type;

  /* By default, things in classes are private, while things in
     structures or unions are public.  */
  current_access_specifier = (CLASSTYPE_DECLARED_CLASS (type) 
			      ? access_private_node 
			      : access_public_node);

  if (previous_class_type != NULL_TREE
      && (type != previous_class_type 
	  || TYPE_SIZE (previous_class_type) == NULL_TREE)
      && current_class_depth == 1)
    {
      /* Forcibly remove any old class remnants.  */
      invalidate_class_lookup_cache ();
    }

  /* If we're about to enter a nested class, clear
     IDENTIFIER_CLASS_VALUE for the enclosing classes.  */
  if (modify && current_class_depth > 1)
    clear_identifier_class_values ();

  pushlevel_class ();

#if 0
  if (CLASSTYPE_TEMPLATE_INFO (type))
    overload_template_name (type);
#endif

  if (modify)
    {
      if (type != previous_class_type || current_class_depth > 1)
	push_class_decls (type);
      else
	{
	  tree item;

	  /* We are re-entering the same class we just left, so we
	     don't have to search the whole inheritance matrix to find
	     all the decls to bind again.  Instead, we install the
	     cached class_shadowed list, and walk through it binding
	     names and setting up IDENTIFIER_TYPE_VALUEs.  */
	  set_class_shadows (previous_class_values);
	  for (item = previous_class_values; item; item = TREE_CHAIN (item))
	    {
	      tree id = TREE_PURPOSE (item);
	      tree decl = TREE_TYPE (item);

	      push_class_binding (id, decl);
	      if (TREE_CODE (decl) == TYPE_DECL)
		set_identifier_type_value (id, TREE_TYPE (decl));
	    }
	  unuse_fields (type);
	}

      storetags (CLASSTYPE_TAGS (type));
    }
}

/* When we exit a toplevel class scope, we save the
   IDENTIFIER_CLASS_VALUEs so that we can restore them quickly if we
   reenter the class.  Here, we've entered some other class, so we
   must invalidate our cache.  */

void
invalidate_class_lookup_cache ()
{
  tree t;
  
  /* This code can be seen as a cache miss.  When we've cached a
     class' scope's bindings and we can't use them, we need to reset
     them.  This is it!  */
  for (t = previous_class_values; t; t = TREE_CHAIN (t))
    IDENTIFIER_CLASS_VALUE (TREE_PURPOSE (t)) = NULL_TREE;
  
  previous_class_type = NULL_TREE;
}
 
/* Get out of the current class scope. If we were in a class scope
   previously, that is the one popped to.  */

void
popclass ()
{
  poplevel_class ();
  /* Since poplevel_class does the popping of class decls nowadays,
     this really only frees the obstack used for these decls.  */
  pop_class_decls ();

  current_class_depth--;
  current_class_name = current_class_stack[current_class_depth].name;
  current_class_type = current_class_stack[current_class_depth].type;
  current_access_specifier = current_class_stack[current_class_depth].access;
  if (current_class_stack[current_class_depth].names_used)
    splay_tree_delete (current_class_stack[current_class_depth].names_used);
}

/* Returns 1 if current_class_type is either T or a nested type of T.  */

int
currently_open_class (t)
     tree t;
{
  int i;
  if (t == current_class_type)
    return 1;
  for (i = 0; i < current_class_depth; ++i)
    if (current_class_stack [i].type == t)
      return 1;
  return 0;
}

/* When entering a class scope, all enclosing class scopes' names with
   static meaning (static variables, static functions, types and enumerators)
   have to be visible.  This recursive function calls pushclass for all
   enclosing class contexts until global or a local scope is reached.
   TYPE is the enclosed class and MODIFY is equivalent with the pushclass
   formal of the same name.  */

void
push_nested_class (type, modify)
     tree type;
     int modify;
{
  tree context;

  /* A namespace might be passed in error cases, like A::B:C.  */
  if (type == NULL_TREE || type == error_mark_node || ! IS_AGGR_TYPE (type)
      || TREE_CODE (type) == NAMESPACE_DECL
      || TREE_CODE (type) == TEMPLATE_TYPE_PARM
      || TREE_CODE (type) == TEMPLATE_TEMPLATE_PARM)
    return;
  
  context = DECL_CONTEXT (TYPE_MAIN_DECL (type));

  if (context && CLASS_TYPE_P (context))
    push_nested_class (context, 2);
  pushclass (type, modify);
}

/* Undoes a push_nested_class call.  MODIFY is passed on to popclass.  */

void
pop_nested_class ()
{
  tree context = DECL_CONTEXT (TYPE_MAIN_DECL (current_class_type));

  popclass ();
  if (context && CLASS_TYPE_P (context))
    pop_nested_class ();
}

/* Set global variables CURRENT_LANG_NAME to appropriate value
   so that behavior of name-mangling machinery is correct.  */

void
push_lang_context (name)
     tree name;
{
  *current_lang_stack++ = current_lang_name;
  if (current_lang_stack - &VARRAY_TREE (current_lang_base, 0)
      >= (ptrdiff_t) VARRAY_SIZE (current_lang_base))
    {
      size_t old_size = VARRAY_SIZE (current_lang_base);

      VARRAY_GROW (current_lang_base, old_size + 10);
      current_lang_stack = &VARRAY_TREE (current_lang_base, old_size);
    }

  if (name == lang_name_cplusplus)
    {
      strict_prototype = strict_prototypes_lang_cplusplus;
      current_lang_name = name;
    }
  else if (name == lang_name_java)
    {
      strict_prototype = strict_prototypes_lang_cplusplus;
      current_lang_name = name;
      /* DECL_IGNORED_P is initially set for these types, to avoid clutter.
	 (See record_builtin_java_type in decl.c.)  However, that causes
	 incorrect debug entries if these types are actually used.
	 So we re-enable debug output after extern "Java". */
      DECL_IGNORED_P (java_byte_type_node) = 0;
      DECL_IGNORED_P (java_short_type_node) = 0;
      DECL_IGNORED_P (java_int_type_node) = 0;
      DECL_IGNORED_P (java_long_type_node) = 0;
      DECL_IGNORED_P (java_float_type_node) = 0;
      DECL_IGNORED_P (java_double_type_node) = 0;
      DECL_IGNORED_P (java_char_type_node) = 0;
      DECL_IGNORED_P (java_boolean_type_node) = 0;
    }
  else if (name == lang_name_c)
    {
      strict_prototype = strict_prototypes_lang_c;
      current_lang_name = name;
    }
  else
    error ("language string `\"%s\"' not recognized", IDENTIFIER_POINTER (name));
}
  
/* Get out of the current language scope.  */

void
pop_lang_context ()
{
  /* Clear the current entry so that garbage collector won't hold on
     to it.  */
  *current_lang_stack = NULL_TREE;
  current_lang_name = *--current_lang_stack;
  if (current_lang_name == lang_name_cplusplus
      || current_lang_name == lang_name_java)
    strict_prototype = strict_prototypes_lang_cplusplus;
  else if (current_lang_name == lang_name_c)
    strict_prototype = strict_prototypes_lang_c;
}
\f
/* Type instantiation routines.  */

/* Given an OVERLOAD and a TARGET_TYPE, return the function that
   matches the TARGET_TYPE.  If there is no satisfactory match, return
   error_mark_node, and issue an error message if COMPLAIN is
   non-zero.  If TEMPLATE_ONLY, the name of the overloaded function
   was a template-id, and EXPLICIT_TARGS are the explicitly provided
   template arguments.  */

static tree
resolve_address_of_overloaded_function (target_type, 
					overload,
					complain, 
					template_only,
					explicit_targs)
     tree target_type;
     tree overload;
     int complain;
     int template_only;
     tree explicit_targs;
{
  /* Here's what the standard says:
     
       [over.over]

       If the name is a function template, template argument deduction
       is done, and if the argument deduction succeeds, the deduced
       arguments are used to generate a single template function, which
       is added to the set of overloaded functions considered.

       Non-member functions and static member functions match targets of
       type "pointer-to-function" or "reference-to-function."  Nonstatic
       member functions match targets of type "pointer-to-member
       function;" the function type of the pointer to member is used to
       select the member function from the set of overloaded member
       functions.  If a nonstatic member function is selected, the
       reference to the overloaded function name is required to have the
       form of a pointer to member as described in 5.3.1.

       If more than one function is selected, any template functions in
       the set are eliminated if the set also contains a non-template
       function, and any given template function is eliminated if the
       set contains a second template function that is more specialized
       than the first according to the partial ordering rules 14.5.5.2.
       After such eliminations, if any, there shall remain exactly one
       selected function.  */

  int is_ptrmem = 0;
  int is_reference = 0;
  /* We store the matches in a TREE_LIST rooted here.  The functions
     are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
     interoperability with most_specialized_instantiation.  */
  tree matches = NULL_TREE;
  tree fn;

  /* By the time we get here, we should be seeing only real
     pointer-to-member types, not the internal POINTER_TYPE to
     METHOD_TYPE representation.  */
  my_friendly_assert (!(TREE_CODE (target_type) == POINTER_TYPE
			&& (TREE_CODE (TREE_TYPE (target_type)) 
			    == METHOD_TYPE)), 0);

  /* Check that the TARGET_TYPE is reasonable.  */
  if (TYPE_PTRFN_P (target_type))
    /* This is OK.  */
    ;
  else if (TYPE_PTRMEMFUNC_P (target_type))
    /* This is OK, too.  */
    is_ptrmem = 1;
  else if (TREE_CODE (target_type) == FUNCTION_TYPE)
    {
      /* This is OK, too.  This comes from a conversion to reference
	 type.  */
      target_type = build_reference_type (target_type);
      is_reference = 1;
    }
  else 
    {
      if (complain)
	cp_error("cannot resolve overloaded function `%D' based on conversion to type `%T'", 
		 DECL_NAME (OVL_FUNCTION (overload)), target_type);
      return error_mark_node;
    }
  
  /* If we can find a non-template function that matches, we can just
     use it.  There's no point in generating template instantiations
     if we're just going to throw them out anyhow.  But, of course, we
     can only do this when we don't *need* a template function.  */
  if (!template_only)
    {
      tree fns;

      for (fns = overload; fns; fns = OVL_CHAIN (fns))
	{
	  tree fn = OVL_FUNCTION (fns);
	  tree fntype;

	  if (TREE_CODE (fn) == TEMPLATE_DECL)
	    /* We're not looking for templates just yet.  */
	    continue;

	  if ((TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE)
	      != is_ptrmem)
	    /* We're looking for a non-static member, and this isn't
	       one, or vice versa.  */
	    continue;
	
	  /* See if there's a match.  */
	  fntype = TREE_TYPE (fn);
	  if (is_ptrmem)
	    fntype = build_ptrmemfunc_type (build_pointer_type (fntype));
	  else if (!is_reference)
	    fntype = build_pointer_type (fntype);

	  if (can_convert_arg (target_type, fntype, fn))
	    matches = tree_cons (fn, NULL_TREE, matches);
	}
    }

  /* Now, if we've already got a match (or matches), there's no need
     to proceed to the template functions.  But, if we don't have a
     match we need to look at them, too.  */
  if (!matches) 
    {
      tree target_fn_type;
      tree target_arg_types;
      tree fns;

      if (is_ptrmem)
	target_fn_type
	  = TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (target_type));
      else
	target_fn_type = TREE_TYPE (target_type);
      target_arg_types = TYPE_ARG_TYPES (target_fn_type);
	  
      for (fns = overload; fns; fns = OVL_CHAIN (fns))
	{
	  tree fn = OVL_FUNCTION (fns);
	  tree instantiation;
	  tree instantiation_type;
	  tree targs;

	  if (TREE_CODE (fn) != TEMPLATE_DECL)
	    /* We're only looking for templates.  */
	    continue;

	  if ((TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE)
	      != is_ptrmem)
	    /* We're not looking for a non-static member, and this is
	       one, or vice versa.  */
	    continue;

	  /* Try to do argument deduction.  */
	  targs = make_tree_vec (DECL_NTPARMS (fn));
	  if (fn_type_unification (fn, explicit_targs, targs,
				   target_arg_types, NULL_TREE,
				   DEDUCE_EXACT) != 0)
	    /* Argument deduction failed.  */
	    continue;

	  /* Instantiate the template.  */
	  instantiation = instantiate_template (fn, targs);
	  if (instantiation == error_mark_node)
	    /* Instantiation failed.  */
	    continue;

	  /* See if there's a match.  */
	  instantiation_type = TREE_TYPE (instantiation);
	  if (is_ptrmem)
	    instantiation_type = 
	      build_ptrmemfunc_type (build_pointer_type (instantiation_type));
	  else if (!is_reference)
	    instantiation_type = build_pointer_type (instantiation_type);
	  if (can_convert_arg (target_type, instantiation_type, instantiation))
	    matches = tree_cons (instantiation, fn, matches);
	}

      /* Now, remove all but the most specialized of the matches.  */
      if (matches)
	{
	  tree match = most_specialized_instantiation (matches, 
						       explicit_targs);

	  if (match != error_mark_node)
	    matches = tree_cons (match, NULL_TREE, NULL_TREE);
	}
    }

  /* Now we should have exactly one function in MATCHES.  */
  if (matches == NULL_TREE)
    {
      /* There were *no* matches.  */
      if (complain)
	{
 	  cp_error ("no matches converting function `%D' to type `%#T'", 
		    DECL_NAME (OVL_FUNCTION (overload)),
		    target_type);

	  /* print_candidates expects a chain with the functions in
             TREE_VALUE slots, so we cons one up here (we're losing anyway,
             so why be clever?).  */
          for (; overload; overload = OVL_NEXT (overload))
            matches = tree_cons (NULL_TREE, OVL_CURRENT (overload),
				 matches);
          
	  print_candidates (matches);
	}
      return error_mark_node;
    }
  else if (TREE_CHAIN (matches))
    {
      /* There were too many matches.  */

      if (complain)
	{
	  tree match;

 	  cp_error ("converting overloaded function `%D' to type `%#T' is ambiguous", 
		    DECL_NAME (OVL_FUNCTION (overload)),
		    target_type);

	  /* Since print_candidates expects the functions in the
	     TREE_VALUE slot, we flip them here.  */
	  for (match = matches; match; match = TREE_CHAIN (match))
	    TREE_VALUE (match) = TREE_PURPOSE (match);

	  print_candidates (matches);
	}
      
      return error_mark_node;
    }

  /* Good, exactly one match.  Now, convert it to the correct type.  */
  fn = TREE_PURPOSE (matches);

  mark_used (fn);

  if (TYPE_PTRFN_P (target_type) || TYPE_PTRMEMFUNC_P (target_type))
    return build_unary_op (ADDR_EXPR, fn, 0);
  else
    {
      /* The target must be a REFERENCE_TYPE.  Above, build_unary_op
	 will mark the function as addressed, but here we must do it
	 explicitly.  */
      mark_addressable (fn);

      return fn;
    }
}

/* This function will instantiate the type of the expression given in
   RHS to match the type of LHSTYPE.  If errors exist, then return
   error_mark_node.  We only complain is COMPLAIN is set.  If we are
   not complaining, never modify rhs, as overload resolution wants to
   try many possible instantiations, in hopes that at least one will
   work.

   FLAGS is a bitmask, as we see at the top of the function.

   For non-recursive calls, LHSTYPE should be a function, pointer to
   function, or a pointer to member function.  */

tree
instantiate_type (lhstype, rhs, flags)
     tree lhstype, rhs;
     int flags;
{
  int complain = (flags & 1);
  int strict = (flags & 2) ? COMPARE_NO_ATTRIBUTES : COMPARE_STRICT;

  if (TREE_CODE (lhstype) == UNKNOWN_TYPE)
    {
      if (complain)
	error ("not enough type information");
      return error_mark_node;
    }

  if (TREE_TYPE (rhs) != NULL_TREE && ! (type_unknown_p (rhs)))
    {
      if (comptypes (lhstype, TREE_TYPE (rhs), strict))
	return rhs;
      if (complain)
	cp_error ("argument of type `%T' does not match `%T'",
		  TREE_TYPE (rhs), lhstype);
      return error_mark_node;
    }

  /* We don't overwrite rhs if it is an overloaded function.
     Copying it would destroy the tree link.  */
  if (TREE_CODE (rhs) != OVERLOAD)
    rhs = copy_node (rhs);

  /* This should really only be used when attempting to distinguish
     what sort of a pointer to function we have.  For now, any
     arithmetic operation which is not supported on pointers
     is rejected as an error.  */

  switch (TREE_CODE (rhs))
    {
    case TYPE_EXPR:
    case CONVERT_EXPR:
    case SAVE_EXPR:
    case CONSTRUCTOR:
    case BUFFER_REF:
      my_friendly_abort (177);
      return error_mark_node;

    case INDIRECT_REF:
    case ARRAY_REF:
      {
	tree new_rhs;

	new_rhs = instantiate_type (build_pointer_type (lhstype),
				    TREE_OPERAND (rhs, 0), flags);
	if (new_rhs == error_mark_node)
	  return error_mark_node;

	TREE_TYPE (rhs) = lhstype;
	TREE_OPERAND (rhs, 0) = new_rhs;
	return rhs;
      }

    case NOP_EXPR:
      rhs = copy_node (TREE_OPERAND (rhs, 0));
      TREE_TYPE (rhs) = unknown_type_node;
      return instantiate_type (lhstype, rhs, flags);

    case COMPONENT_REF:
      {
	tree r = instantiate_type (lhstype, TREE_OPERAND (rhs, 1), flags);

	if (r != error_mark_node && TYPE_PTRMEMFUNC_P (lhstype)
	    && complain && !flag_ms_extensions)
	  {
	    /* Note: we check this after the recursive call to avoid
	       complaining about cases where overload resolution fails.  */

	    tree t = TREE_TYPE (TREE_OPERAND (rhs, 0));
	    tree fn = PTRMEM_CST_MEMBER (r);

	    my_friendly_assert (TREE_CODE (r) == PTRMEM_CST, 990811);

	    cp_pedwarn
	      ("object-dependent reference to `%E' can only be used in a call",
	       DECL_NAME (fn));
	    cp_pedwarn
	      ("  to form a pointer to member function, say `&%T::%E'",
	       t, DECL_NAME (fn));
	  }

	return r;
      }

    case OFFSET_REF:
      rhs = TREE_OPERAND (rhs, 1);
      if (BASELINK_P (rhs))
	return instantiate_type (lhstype, TREE_VALUE (rhs), flags);

      /* This can happen if we are forming a pointer-to-member for a
	 member template.  */
      my_friendly_assert (TREE_CODE (rhs) == TEMPLATE_ID_EXPR, 0);

      /* Fall through.  */

    case TEMPLATE_ID_EXPR:
      return 
	resolve_address_of_overloaded_function (lhstype,
						TREE_OPERAND (rhs, 0),
						complain,
						/*template_only=*/1,
						TREE_OPERAND (rhs, 1));

    case OVERLOAD:
      return 
	resolve_address_of_overloaded_function (lhstype, 
						rhs,
						complain,
						/*template_only=*/0,
						/*explicit_targs=*/NULL_TREE);

    case TREE_LIST:
      /* Now we should have a baselink. */
      my_friendly_assert (BASELINK_P (rhs), 990412);

      return instantiate_type (lhstype, TREE_VALUE (rhs), flags);

    case CALL_EXPR:
      /* This is too hard for now.  */
      my_friendly_abort (183);
      return error_mark_node;

    case PLUS_EXPR:
    case MINUS_EXPR:
    case COMPOUND_EXPR:
      TREE_OPERAND (rhs, 0)
	= instantiate_type (lhstype, TREE_OPERAND (rhs, 0), flags);
      if (TREE_OPERAND (rhs, 0) == error_mark_node)
	return error_mark_node;
      TREE_OPERAND (rhs, 1)
	= instantiate_type (lhstype, TREE_OPERAND (rhs, 1), flags);
      if (TREE_OPERAND (rhs, 1) == error_mark_node)
	return error_mark_node;

      TREE_TYPE (rhs) = lhstype;
      return rhs;

    case MULT_EXPR:
    case TRUNC_DIV_EXPR:
    case FLOOR_DIV_EXPR:
    case CEIL_DIV_EXPR:
    case ROUND_DIV_EXPR:
    case RDIV_EXPR:
    case TRUNC_MOD_EXPR:
    case FLOOR_MOD_EXPR:
    case CEIL_MOD_EXPR:
    case ROUND_MOD_EXPR:
    case FIX_ROUND_EXPR:
    case FIX_FLOOR_EXPR:
    case FIX_CEIL_EXPR:
    case FIX_TRUNC_EXPR:
    case FLOAT_EXPR:
    case NEGATE_EXPR:
    case ABS_EXPR:
    case MAX_EXPR:
    case MIN_EXPR:
    case FFS_EXPR:

    case BIT_AND_EXPR:
    case BIT_IOR_EXPR:
    case BIT_XOR_EXPR:
    case LSHIFT_EXPR:
    case RSHIFT_EXPR:
    case LROTATE_EXPR:
    case RROTATE_EXPR:

    case PREINCREMENT_EXPR:
    case PREDECREMENT_EXPR:
    case POSTINCREMENT_EXPR:
    case POSTDECREMENT_EXPR:
      if (complain)
	error ("invalid operation on uninstantiated type");
      return error_mark_node;

    case TRUTH_AND_EXPR:
    case TRUTH_OR_EXPR:
    case TRUTH_XOR_EXPR:
    case LT_EXPR:
    case LE_EXPR:
    case GT_EXPR:
    case GE_EXPR:
    case EQ_EXPR:
    case NE_EXPR:
    case TRUTH_ANDIF_EXPR:
    case TRUTH_ORIF_EXPR:
    case TRUTH_NOT_EXPR:
      if (complain)
	error ("not enough type information");
      return error_mark_node;

    case COND_EXPR:
      if (type_unknown_p (TREE_OPERAND (rhs, 0)))
	{
	  if (complain)
	    error ("not enough type information");
	  return error_mark_node;
	}
      TREE_OPERAND (rhs, 1)
	= instantiate_type (lhstype, TREE_OPERAND (rhs, 1), flags);
      if (TREE_OPERAND (rhs, 1) == error_mark_node)
	return error_mark_node;
      TREE_OPERAND (rhs, 2)
	= instantiate_type (lhstype, TREE_OPERAND (rhs, 2), flags);
      if (TREE_OPERAND (rhs, 2) == error_mark_node)
	return error_mark_node;

      TREE_TYPE (rhs) = lhstype;
      return rhs;

    case MODIFY_EXPR:
      TREE_OPERAND (rhs, 1)
	= instantiate_type (lhstype, TREE_OPERAND (rhs, 1), flags);
      if (TREE_OPERAND (rhs, 1) == error_mark_node)
	return error_mark_node;

      TREE_TYPE (rhs) = lhstype;
      return rhs;
      
    case ADDR_EXPR:
      return instantiate_type (lhstype, TREE_OPERAND (rhs, 0), flags);

    case ENTRY_VALUE_EXPR:
      my_friendly_abort (184);
      return error_mark_node;

    case ERROR_MARK:
      return error_mark_node;

    default:
      my_friendly_abort (185);
      return error_mark_node;
    }
}
\f
/* Return the name of the virtual function pointer field
   (as an IDENTIFIER_NODE) for the given TYPE.  Note that
   this may have to look back through base types to find the
   ultimate field name.  (For single inheritance, these could
   all be the same name.  Who knows for multiple inheritance).  */

static tree
get_vfield_name (type)
     tree type;
{
  tree binfo = TYPE_BINFO (type);
  char *buf;

  while (BINFO_BASETYPES (binfo)
	 && TYPE_POLYMORPHIC_P (BINFO_TYPE (BINFO_BASETYPE (binfo, 0)))
	 && ! TREE_VIA_VIRTUAL (BINFO_BASETYPE (binfo, 0)))
    binfo = BINFO_BASETYPE (binfo, 0);

  type = BINFO_TYPE (binfo);
  buf = (char *) alloca (sizeof (VFIELD_NAME_FORMAT)
			 + TYPE_NAME_LENGTH (type) + 2);
  sprintf (buf, VFIELD_NAME_FORMAT, TYPE_NAME_STRING (type));
  return get_identifier (buf);
}

void
print_class_statistics ()
{
#ifdef GATHER_STATISTICS
  fprintf (stderr, "convert_harshness = %d\n", n_convert_harshness);
  fprintf (stderr, "compute_conversion_costs = %d\n", n_compute_conversion_costs);
  fprintf (stderr, "build_method_call = %d (inner = %d)\n",
	   n_build_method_call, n_inner_fields_searched);
  if (n_vtables)
    {
      fprintf (stderr, "vtables = %d; vtable searches = %d\n",
	       n_vtables, n_vtable_searches);
      fprintf (stderr, "vtable entries = %d; vtable elems = %d\n",
	       n_vtable_entries, n_vtable_elems);
    }
#endif
}

/* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
   according to [class]:
                                          The class-name is also inserted
   into  the scope of the class itself.  For purposes of access checking,
   the inserted class name is treated as if it were a public member name.  */

void
build_self_reference ()
{
  tree name = constructor_name (current_class_type);
  tree value = build_lang_decl (TYPE_DECL, name, current_class_type);
  tree saved_cas;

  DECL_NONLOCAL (value) = 1;
  DECL_CONTEXT (value) = current_class_type;
  DECL_CLASS_CONTEXT (value) = current_class_type;
  DECL_ARTIFICIAL (value) = 1;

  if (processing_template_decl)
    value = push_template_decl (value);

  saved_cas = current_access_specifier;
  current_access_specifier = access_public_node;
  finish_member_declaration (value);
  current_access_specifier = saved_cas;
}

/* Returns 1 if TYPE contains only padding bytes.  */

int
is_empty_class (type)
     tree type;
{
  tree t;

  if (type == error_mark_node)
    return 0;

  if (! IS_AGGR_TYPE (type))
    return 0;

  if (flag_new_abi)
    return CLASSTYPE_SIZE (type) == integer_zero_node;

  if (TYPE_BINFO_BASETYPES (type))
    return 0;
  t = TYPE_FIELDS (type);
  while (t && TREE_CODE (t) != FIELD_DECL)
    t = TREE_CHAIN (t);
  return (t == NULL_TREE);
}

/* Find the enclosing class of the given NODE.  NODE can be a *_DECL or
   a *_TYPE node.  NODE can also be a local class.  */

tree
get_enclosing_class (type)
     tree type;
{
  tree node = type;

  while (node && TREE_CODE (node) != NAMESPACE_DECL)
    {
      switch (TREE_CODE_CLASS (TREE_CODE (node)))
	{
	case 'd':
	  node = DECL_CONTEXT (node);
	  break;

	case 't':
	  if (node != type)
	    return node;
	  node = TYPE_CONTEXT (node);
	  break;

	default:
	  my_friendly_abort (0);
	}
    }
  return NULL_TREE;
}

/* Return 1 if TYPE or one of its enclosing classes is derived from BASE.  */

int
is_base_of_enclosing_class (base, type)
     tree base, type;
{
  while (type)
    {
      if (get_binfo (base, type, 0))
	return 1;

      type = get_enclosing_class (type);
    }
  return 0;
}

/* Note that NAME was looked up while the current class was being
   defined and that the result of that lookup was DECL.  */

void
maybe_note_name_used_in_class (name, decl)
     tree name;
     tree decl;
{
  splay_tree names_used;

  /* If we're not defining a class, there's nothing to do.  */
  if (!current_class_type || !TYPE_BEING_DEFINED (current_class_type))
    return;
  
  /* If there's already a binding for this NAME, then we don't have
     anything to worry about.  */
  if (IDENTIFIER_CLASS_VALUE (name))
    return;

  if (!current_class_stack[current_class_depth - 1].names_used)
    current_class_stack[current_class_depth - 1].names_used
      = splay_tree_new (splay_tree_compare_pointers, 0, 0);
  names_used = current_class_stack[current_class_depth - 1].names_used;

  splay_tree_insert (names_used,
		     (splay_tree_key) name, 
		     (splay_tree_value) decl);
}

/* Note that NAME was declared (as DECL) in the current class.  Check
   to see that the declaration is legal.  */

void
note_name_declared_in_class (name, decl)
     tree name;
     tree decl;
{
  splay_tree names_used;
  splay_tree_node n;

  /* Look to see if we ever used this name.  */
  names_used 
    = current_class_stack[current_class_depth - 1].names_used;
  if (!names_used)
    return;

  n = splay_tree_lookup (names_used, (splay_tree_key) name);
  if (n)
    {
      /* [basic.scope.class]
	 
	 A name N used in a class S shall refer to the same declaration
	 in its context and when re-evaluated in the completed scope of
	 S.  */
      cp_error ("declaration of `%#D'", decl);
      cp_error_at ("changes meaning of `%s' from `%+#D'", 
		   IDENTIFIER_POINTER (DECL_NAME (decl)),
		   (tree) n->value);
    }
}