[pf3gnuchains/gcc-fork.git] / gcc / cp / decl.c

/* Process declarations and variables for C compiler.
   Copyright (C) 1988, 92-98, 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.  */


/* Process declarations and symbol lookup for C front end.
   Also constructs types; the standard scalar types at initialization,
   and structure, union, array and enum types when they are declared.  */

/* ??? not all decl nodes are given the most useful possible
   line numbers.  For example, the CONST_DECLs for enum values.  */

#include "config.h"
#include "system.h"
#include "tree.h"
#include "rtl.h"
#include "flags.h"
#include "cp-tree.h"
#include "decl.h"
#include "lex.h"
#include <signal.h>
#include "obstack.h"
#include "defaults.h"
#include "output.h"
#include "except.h"
#include "toplev.h"
#include "../hash.h"
#include "defaults.h"
#include "ggc.h"

#define obstack_chunk_alloc xmalloc
#define obstack_chunk_free free

extern struct obstack permanent_obstack;
extern struct obstack* saveable_obstack;

extern int current_class_depth;

extern tree static_ctors, static_dtors;

extern tree global_namespace;

extern int (*valid_lang_attribute) PROTO ((tree, tree, tree, tree));

/* Use garbage collection.  */

int ggc_p = 1;

#ifndef WCHAR_UNSIGNED
#define WCHAR_UNSIGNED 0
#endif

#ifndef CHAR_TYPE_SIZE
#define CHAR_TYPE_SIZE BITS_PER_UNIT
#endif

#ifndef BOOL_TYPE_SIZE
#ifdef SLOW_BYTE_ACCESS
#define BOOL_TYPE_SIZE ((SLOW_BYTE_ACCESS) ? (POINTER_SIZE) : (CHAR_TYPE_SIZE))
#else
#define BOOL_TYPE_SIZE CHAR_TYPE_SIZE
#endif
#endif

/* We let tm.h override the types used here, to handle trivial differences
   such as the choice of unsigned int or long unsigned int for size_t.
   When machines start needing nontrivial differences in the size type,
   it would be best to do something here to figure out automatically
   from other information what type to use.  */

#ifndef SIZE_TYPE
#define SIZE_TYPE "long unsigned int"
#endif

#ifndef PTRDIFF_TYPE
#define PTRDIFF_TYPE "long int"
#endif

#ifndef WCHAR_TYPE
#define WCHAR_TYPE "int"
#endif

static tree grokparms                           PROTO((tree, int));
static const char *redeclaration_error_message  PROTO((tree, tree));

static void push_binding_level PROTO((struct binding_level *, int,
                                      int));
static void pop_binding_level PROTO((void));
static void suspend_binding_level PROTO((void));
static void resume_binding_level PROTO((struct binding_level *));
static struct binding_level *make_binding_level PROTO((void));
static void declare_namespace_level PROTO((void));
static void signal_catch PROTO((int)) ATTRIBUTE_NORETURN;
static void storedecls PROTO((tree));
static void require_complete_types_for_parms PROTO((tree));
static void push_overloaded_decl_1 PROTO((tree));
static int ambi_op_p PROTO((tree));
static int unary_op_p PROTO((tree));
static tree store_bindings PROTO((tree, tree));
static tree lookup_tag_reverse PROTO((tree, tree));
static tree obscure_complex_init PROTO((tree, tree));
static tree maybe_build_cleanup_1 PROTO((tree, tree));
static tree lookup_name_real PROTO((tree, int, int, int));
static void warn_extern_redeclared_static PROTO((tree, tree));
static void grok_reference_init PROTO((tree, tree, tree));
static tree grokfndecl PROTO((tree, tree, tree, tree, int,
                              enum overload_flags, tree,
                              tree, int, int, int, int, int, int, tree));
static tree grokvardecl PROTO((tree, tree, RID_BIT_TYPE *, int, int, tree));
static tree lookup_tag PROTO((enum tree_code, tree,
                              struct binding_level *, int));
static void set_identifier_type_value_with_scope
        PROTO((tree, tree, struct binding_level *));
static void record_builtin_type PROTO((enum rid, const char *, tree));
static void record_unknown_type PROTO((tree, const char *));
static int member_function_or_else PROTO((tree, tree, const char *));
static void bad_specifiers PROTO((tree, const char *, int, int, int, int,
                                  int));
static void lang_print_error_function PROTO((const char *));
static tree maybe_process_template_type_declaration PROTO((tree, int, struct binding_level*));
static void check_for_uninitialized_const_var PROTO((tree));
static unsigned long typename_hash PROTO((hash_table_key));
static boolean typename_compare PROTO((hash_table_key, hash_table_key));
static void push_binding PROTO((tree, tree, struct binding_level*));
static int add_binding PROTO((tree, tree));
static void pop_binding PROTO((tree, tree));
static tree local_variable_p PROTO((tree *));
static tree find_binding PROTO((tree, tree));
static tree select_decl PROTO((tree, int));
static int lookup_flags PROTO((int, int));
static tree qualify_lookup PROTO((tree, int));
static tree record_builtin_java_type PROTO((const char *, int));
static const char *tag_name PROTO((enum tag_types code));
static void find_class_binding_level PROTO((void));
static struct binding_level *innermost_nonclass_level PROTO((void));
static void warn_about_implicit_typename_lookup PROTO((tree, tree));
static int walk_namespaces_r PROTO((tree, walk_namespaces_fn, void *));
static int walk_globals_r PROTO((tree, void *));
static void add_decl_to_level PROTO((tree, struct binding_level *));
static tree make_label_decl PROTO((tree, int));
static void pop_label PROTO((tree));
static void pop_labels PROTO((tree));
static void maybe_deduce_size_from_array_init PROTO((tree, tree));
static void layout_var_decl PROTO((tree));
static void maybe_commonize_var PROTO((tree));
static tree check_initializer PROTO((tree, tree));
static void make_rtl_for_nonlocal_decl PROTO((tree, tree, const char *));
static void push_cp_function_context PROTO((struct function *));
static void pop_cp_function_context PROTO((struct function *));
static void mark_binding_level PROTO((void *));
static void mark_cp_function_context PROTO((struct function *));
static void mark_saved_scope PROTO((void *));
static void mark_lang_function PROTO((struct language_function *));
static void save_function_data PROTO((tree));
static void check_function_type PROTO((tree));
static void destroy_local_static PROTO((tree));
static void destroy_local_var PROTO((tree));
static void finish_constructor_body PROTO((void));
static void finish_destructor_body PROTO((void));

#if defined (DEBUG_CP_BINDING_LEVELS)
static void indent PROTO((void));
#endif

/* Erroneous argument lists can use this *IFF* they do not modify it.  */
tree error_mark_list;

/* The following symbols are subsumed in the cp_global_trees array, and
   listed here individually for documentation purposes. 

   C++ extensions
        tree wchar_decl_node;
        tree void_zero_node;

        tree vtable_entry_type;
        tree delta_type_node;
#if 0
   Old rtti stuff.
        tree __baselist_desc_type_node;
        tree __i_desc_type_node, __m_desc_type_node;
        tree __t_desc_array_type, __i_desc_array_type, __m_desc_array_type;
#endif
        tree __t_desc_type_node;
#if 0
        tree __tp_desc_type_node;
#endif
        tree __access_mode_type_node;
        tree __bltn_desc_type_node, __user_desc_type_node, __class_desc_type_node;
        tree __ptr_desc_type_node, __attr_desc_type_node, __func_desc_type_node;
        tree __ptmf_desc_type_node, __ptmd_desc_type_node;
#if 0
   Not needed yet?  May be needed one day?
        tree __bltn_desc_array_type, __user_desc_array_type, __class_desc_array_type;
        tree __ptr_desc_array_type, __attr_dec_array_type, __func_desc_array_type;
        tree __ptmf_desc_array_type, __ptmd_desc_array_type;
#endif

        tree class_star_type_node;
        tree class_type_node, record_type_node, union_type_node, enum_type_node;
        tree unknown_type_node;

   Array type `vtable_entry_type[]'

        tree vtbl_type_node;
        tree vtbl_ptr_type_node;

   Nnamespace std

        tree std_node;

   A FUNCTION_DECL which can call `abort'.  Not necessarily the
   one that the user will declare, but sufficient to be called
   by routines that want to abort the program.

        tree abort_fndecl;

   The FUNCTION_DECL for the default `::operator delete'.

        tree global_delete_fndecl;

   Used by RTTI
        tree type_info_type_node, tinfo_fn_id, tinfo_fn_type;

*/

tree cp_global_trees[CPTI_MAX];

/* Indicates that there is a type value in some namespace, although
   that is not necessarily in scope at the moment.  */

static tree global_type_node;

/* Namespace std.  */
int in_std;

/* Expect only namespace names now. */
static int only_namespace_names;

/* In a destructor, the last insn emitted after the start of the
   function and the parms.  */

#define last_dtor_insn cp_function_chain->x_last_dtor_insn

/* In a constructor, the last insn emitted after the start of the
   function and the parms, the exception specification and any
   function-try-block.  The constructor initializers are emitted after
   this insn.  */

#define last_parm_cleanup_insn cp_function_chain->x_last_parm_cleanup_insn

/* If original DECL_RESULT of current function was a register,
   but due to being an addressable named return value, would up
   on the stack, this variable holds the named return value's
   original location.  */

#define original_result_rtx cp_function_chain->x_result_rtx

struct named_label_list
{
  struct binding_level *binding_level;
  tree names_in_scope;
  tree label_decl;
  const char *filename_o_goto;
  int lineno_o_goto;
  struct named_label_list *next;
};

/* Used only for jumps to as-yet undefined labels, since jumps to
   defined labels can have their validity checked by stmt.c.  */

#define named_label_uses cp_function_chain->x_named_label_uses

/* A list of objects which have constructors or destructors
   which reside in the global scope.  The decl is stored in
   the TREE_VALUE slot and the initializer is stored
   in the TREE_PURPOSE slot.  */
tree static_aggregates;

/* -- end of C++ */

/* A node for the integer constants 2, and 3.  */

tree integer_two_node, integer_three_node;

/* While defining an enum type, this is 1 plus the last enumerator
   constant value.  */

static tree enum_next_value;

/* Nonzero means that there was overflow computing enum_next_value.  */

static int enum_overflow;

/* Parsing a function declarator leaves here a chain of structure
   and enum types declared in the parmlist.  */

static tree last_function_parm_tags;

/* Similar, for last_function_parm_tags.  */
tree last_function_parms;
static tree current_function_parm_tags;

/* A list (chain of TREE_LIST nodes) of all LABEL_DECLs in the function
   that have names.  Here so we can clear out their names' definitions
   at the end of the function.  The TREE_VALUE is a LABEL_DECL; the
   TREE_PURPOSE is the previous binding of the label.  */

#define named_labels cp_function_chain->x_named_labels

/* The FUNCTION_DECL for the function currently being compiled,
   or 0 if between functions.  */
tree current_function_decl;

/* Set to 0 at beginning of a function definition, and whenever
   a label (case or named) is defined.  Set to value of expression
   returned from function when that value can be transformed into
   a named return value.  */

tree current_function_return_value;

/* Nonzero means give `double' the same size as `float'.  */

extern int flag_short_double;

/* Nonzero means don't recognize any builtin functions.  */

extern int flag_no_builtin;

/* Nonzero means don't recognize the non-ANSI builtin functions.
   -ansi sets this.  */

extern int flag_no_nonansi_builtin;

/* Nonzero means enable obscure ANSI features and disable GNU extensions
   that might cause ANSI-compliant code to be miscompiled.  */

extern int flag_ansi;

/* Nonzero if we want to support huge (> 2^(sizeof(short)*8-1) bytes)
   objects.  */
extern int flag_huge_objects;

/* Nonzero if we want to conserve space in the .o files.  We do this
   by putting uninitialized data and runtime initialized data into
   .common instead of .data at the expense of not flagging multiple
   definitions.  */
extern int flag_conserve_space;
\f
/* C and C++ flags are in decl2.c.  */

/* Flag used when debugging spew.c */

extern int spew_debug;

/* A expression of value 0 with the same precision as a sizetype
   node, but signed.  */
tree signed_size_zero_node;

/* The name of the anonymous namespace, throughout this translation
   unit.  */
tree anonymous_namespace_name;

\f
/* For each binding contour we allocate a binding_level structure
   which records the names defined in that contour.
   Contours include:
    0) the global one
    1) one for each function definition,
       where internal declarations of the parameters appear.
    2) one for each compound statement,
       to record its declarations.

   The current meaning of a name can be found by searching the levels
   from the current one out to the global one.

   Off to the side, may be the class_binding_level.  This exists only
   to catch class-local declarations.  It is otherwise nonexistent.

   Also there may be binding levels that catch cleanups that must be
   run when exceptions occur.  Thus, to see whether a name is bound in
   the current scope, it is not enough to look in the
   CURRENT_BINDING_LEVEL.  You should use lookup_name_current_level
   instead.  */

/* Note that the information in the `names' component of the global contour
   is duplicated in the IDENTIFIER_GLOBAL_VALUEs of all identifiers.  */

struct binding_level
  {
    /* A chain of _DECL nodes for all variables, constants, functions,
       and typedef types.  These are in the reverse of the order
       supplied.  There may be OVERLOADs on this list, too, but they
       are wrapped in TREE_LISTs; the TREE_VALUE is the OVERLOAD.  */
    tree names;

    /* A list of structure, union and enum definitions, for looking up
       tag names.
       It is a chain of TREE_LIST nodes, each of whose TREE_PURPOSE is a name,
       or NULL_TREE; and whose TREE_VALUE is a RECORD_TYPE, UNION_TYPE,
       or ENUMERAL_TYPE node.

       C++: the TREE_VALUE nodes can be simple types for
       component_bindings.  */
    tree tags;

    /* A list of USING_DECL nodes. */
    tree usings;

    /* A list of used namespaces. PURPOSE is the namespace,
       VALUE the common ancestor with this binding_level's namespace. */
    tree using_directives;

    /* If this binding level is the binding level for a class, then
       class_shadowed is a TREE_LIST.  The TREE_PURPOSE of each node
       is the name of an entity bound in the class; the TREE_VALUE is
       the IDENTIFIER_CLASS_VALUE before we entered the class.  Thus,
       when leaving class scope, we can restore the
       IDENTIFIER_CLASS_VALUE by walking this list.  The TREE_TYPE is
       the DECL bound by this name in the class.  */
    tree class_shadowed;

    /* Similar to class_shadowed, but for IDENTIFIER_TYPE_VALUE, and
       is used for all binding levels.  */
    tree type_shadowed;

    /* A TREE_LIST.  Each TREE_VALUE is the LABEL_DECL for a local
       label in this scope.  The TREE_PURPOSE is the previous value of
       the IDENTIFIER_LABEL VALUE.  */
    tree shadowed_labels;

    /* For each level (except not the global one),
       a chain of BLOCK nodes for all the levels
       that were entered and exited one level down.  */
    tree blocks;

    /* The BLOCK node for this level, if one has been preallocated.
       If 0, the BLOCK is allocated (if needed) when the level is popped.  */
    tree this_block;

    /* The binding level which this one is contained in (inherits from).  */
    struct binding_level *level_chain;

    /* List of decls in `names' that have incomplete
       structure or union types.  */
    tree incomplete;

    /* List of VAR_DECLS saved from a previous for statement.
       These would be dead in ANSI-conforming code, but might
       be referenced in ARM-era code.  These are stored in a
       TREE_LIST; the TREE_VALUE is the actual declaration.  */
    tree dead_vars_from_for;

    /* 1 for the level that holds the parameters of a function.
       2 for the level that holds a class declaration.
       3 for levels that hold parameter declarations.  */
    unsigned parm_flag : 4;

    /* 1 means make a BLOCK for this level regardless of all else.
       2 for temporary binding contours created by the compiler.  */
    unsigned keep : 3;

    /* Nonzero if this level "doesn't exist" for tags.  */
    unsigned tag_transparent : 1;

    /* Nonzero if this level can safely have additional
       cleanup-needing variables added to it.  */
    unsigned more_cleanups_ok : 1;
    unsigned have_cleanups : 1;

    /* Nonzero if this level is for storing the decls for template
       parameters and generic decls; these decls will be discarded and
       replaced with a TEMPLATE_DECL.  */
    unsigned pseudo_global : 1;

    /* This is set for a namespace binding level.  */
    unsigned namespace_p : 1;

    /* True if this level is that of a for-statement where we need to
       worry about ambiguous (ARM or ANSI) scope rules.  */
    unsigned is_for_scope : 1;

    /* True if this level corresponds to an EH region, as for a try block.  */
    unsigned eh_region : 1;

    /* One bit left for this word.  */

#if defined(DEBUG_CP_BINDING_LEVELS)
    /* Binding depth at which this level began.  */
    unsigned binding_depth;
#endif /* defined(DEBUG_CP_BINDING_LEVELS) */
  };

#define NULL_BINDING_LEVEL ((struct binding_level *) NULL)
  
/* The binding level currently in effect.  */

#define current_binding_level                   \
  (current_function                             \
   ? cp_function_chain->bindings                \
   : scope_chain->bindings)

/* The binding level of the current class, if any.  */

#define class_binding_level scope_chain->class_bindings

/* A chain of binding_level structures awaiting reuse.  */

static struct binding_level *free_binding_level;

/* The outermost binding level, for names of file scope.
   This is created when the compiler is started and exists
   through the entire run.  */

static struct binding_level *global_binding_level;

/* Nonzero means unconditionally make a BLOCK for the next level pushed.  */

static int keep_next_level_flag;

#if defined(DEBUG_CP_BINDING_LEVELS)
static int binding_depth = 0;
static int is_class_level = 0;

static void
indent ()
{
  register unsigned i;

  for (i = 0; i < binding_depth*2; i++)
    putc (' ', stderr);
}
#endif /* defined(DEBUG_CP_BINDING_LEVELS) */

static tree pushdecl_with_scope PROTO((tree, struct binding_level *));

static void
push_binding_level (newlevel, tag_transparent, keep)
     struct binding_level *newlevel;
     int tag_transparent, keep;
{
  /* Add this level to the front of the chain (stack) of levels that
     are active.  */
  bzero ((char*) newlevel, sizeof (struct binding_level));
  newlevel->level_chain = current_binding_level;
  current_binding_level = newlevel;
  newlevel->tag_transparent = tag_transparent;
  newlevel->more_cleanups_ok = 1;

  /* We are called before expand_start_bindings, but after
     expand_eh_region_start for a try block; so we check this now,
     before the EH block is covered up.  */
  newlevel->eh_region = is_eh_region ();

  newlevel->keep = keep;
#if defined(DEBUG_CP_BINDING_LEVELS)
  newlevel->binding_depth = binding_depth;
  indent ();
  fprintf (stderr, "push %s level 0x%08x line %d\n",
           (is_class_level) ? "class" : "block", newlevel, lineno);
  is_class_level = 0;
  binding_depth++;
#endif /* defined(DEBUG_CP_BINDING_LEVELS) */
}

/* Find the innermost enclosing class scope, and reset
   CLASS_BINDING_LEVEL appropriately.  */

static void
find_class_binding_level ()
{
  struct binding_level *level = current_binding_level;

  while (level && level->parm_flag != 2)
    level = level->level_chain;
  if (level && level->parm_flag == 2)
    class_binding_level = level;
  else
    class_binding_level = 0;
}

static void
pop_binding_level ()
{
  if (global_binding_level)
    {
      /* Cannot pop a level, if there are none left to pop.  */
      if (current_binding_level == global_binding_level)
        my_friendly_abort (123);
    }
  /* Pop the current level, and free the structure for reuse.  */
#if defined(DEBUG_CP_BINDING_LEVELS)
  binding_depth--;
  indent ();
  fprintf (stderr, "pop  %s level 0x%08x line %d\n",
          (is_class_level) ? "class" : "block",
          current_binding_level, lineno);
  if (is_class_level != (current_binding_level == class_binding_level))
    {
      indent ();
      fprintf (stderr, "XXX is_class_level != (current_binding_level == class_binding_level)\n");
    }
  is_class_level = 0;
#endif /* defined(DEBUG_CP_BINDING_LEVELS) */
  {
    register struct binding_level *level = current_binding_level;
    current_binding_level = current_binding_level->level_chain;
    level->level_chain = free_binding_level;
#if 0 /* defined(DEBUG_CP_BINDING_LEVELS) */
    if (level->binding_depth != binding_depth)
      abort ();
#endif /* defined(DEBUG_CP_BINDING_LEVELS) */
    free_binding_level = level;
    find_class_binding_level ();
  }
}

static void
suspend_binding_level ()
{
  if (class_binding_level)
    current_binding_level = class_binding_level;

  if (global_binding_level)
    {
      /* Cannot suspend a level, if there are none left to suspend.  */
      if (current_binding_level == global_binding_level)
        my_friendly_abort (123);
    }
  /* Suspend the current level.  */
#if defined(DEBUG_CP_BINDING_LEVELS)
  binding_depth--;
  indent ();
  fprintf (stderr, "suspend  %s level 0x%08x line %d\n",
          (is_class_level) ? "class" : "block",
          current_binding_level, lineno);
  if (is_class_level != (current_binding_level == class_binding_level))
    {
      indent ();
      fprintf (stderr, "XXX is_class_level != (current_binding_level == class_binding_level)\n");
    }
  is_class_level = 0;
#endif /* defined(DEBUG_CP_BINDING_LEVELS) */
  current_binding_level = current_binding_level->level_chain;
  find_class_binding_level ();
}

static void
resume_binding_level (b)
     struct binding_level *b;
{
  /* Resuming binding levels is meant only for namespaces,
     and those cannot nest into classes. */
  my_friendly_assert(!class_binding_level, 386);
  /* Also, resuming a non-directly nested namespace is a no-no.  */
  my_friendly_assert(b->level_chain == current_binding_level, 386);
  current_binding_level = b;
#if defined(DEBUG_CP_BINDING_LEVELS)
  b->binding_depth = binding_depth;
  indent ();
  fprintf (stderr, "resume %s level 0x%08x line %d\n",
           (is_class_level) ? "class" : "block", b, lineno);
  is_class_level = 0;
  binding_depth++;
#endif /* defined(DEBUG_CP_BINDING_LEVELS) */
}
\f
/* Create a new `struct binding_level'.  */

static
struct binding_level *
make_binding_level ()
{
  /* NOSTRICT */
  return (struct binding_level *) xmalloc (sizeof (struct binding_level));
}

/* Nonzero if we are currently in the global binding level.  */

int
global_bindings_p ()
{
  return current_binding_level == global_binding_level;
}

/* Return the innermost binding level that is not for a class scope.  */

static struct binding_level *
innermost_nonclass_level ()
{
  struct binding_level *b;

  b = current_binding_level;
  while (b->parm_flag == 2)
    b = b->level_chain;

  return b;
}

/* Nonzero if we are currently in a toplevel binding level.  This
   means either the global binding level or a namespace in a toplevel
   binding level.  Since there are no non-toplevel namespace levels,
   this really means any namespace or pseudo-global level.  We also
   include a class whose context is toplevel.  */

int
toplevel_bindings_p ()
{
  struct binding_level *b = innermost_nonclass_level ();

  return b->namespace_p || b->pseudo_global;
}

/* Nonzero if this is a namespace scope, or if we are defining a class
   which is itself at namespace scope, or whose enclosing class is
   such a class, etc.  */

int
namespace_bindings_p ()
{
  struct binding_level *b = innermost_nonclass_level ();

  return b->namespace_p;
}

/* If KEEP is non-zero, make a BLOCK node for the next binding level,
   unconditionally.  Otherwise, use the normal logic to decide whether
   or not to create a BLOCK.  */

void
keep_next_level (keep)
     int keep;
{
  keep_next_level_flag = keep;
}

/* Nonzero if the current level needs to have a BLOCK made.  */

int
kept_level_p ()
{
  return (current_binding_level->blocks != NULL_TREE
          || current_binding_level->keep
          || current_binding_level->names != NULL_TREE
          || (current_binding_level->tags != NULL_TREE
              && !current_binding_level->tag_transparent));
}

void
declare_pseudo_global_level ()
{
  current_binding_level->pseudo_global = 1;
}

static void
declare_namespace_level ()
{
  current_binding_level->namespace_p = 1;
}

int
pseudo_global_level_p ()
{
  return current_binding_level->pseudo_global;
}

void
set_class_shadows (shadows)
     tree shadows;
{
  class_binding_level->class_shadowed = shadows;
}

/* Enter a new binding level.
   If TAG_TRANSPARENT is nonzero, do so only for the name space of variables,
   not for that of tags.  */

void
pushlevel (tag_transparent)
     int tag_transparent;
{
  struct binding_level *newlevel;

  if (current_function && !doing_semantic_analysis_p ())
    return;

  /* Reuse or create a struct for this binding level.  */
#if defined(DEBUG_CP_BINDING_LEVELS)
  if (0)
#else /* !defined(DEBUG_CP_BINDING_LEVELS) */
  if (free_binding_level)
#endif /* !defined(DEBUG_CP_BINDING_LEVELS) */
    {
      newlevel = free_binding_level;
      free_binding_level = free_binding_level->level_chain;
    }
  else
    newlevel = make_binding_level ();

  push_binding_level (newlevel, tag_transparent, keep_next_level_flag);
  GNU_xref_start_scope ((HOST_WIDE_INT) newlevel);
  keep_next_level_flag = 0;
}

void
note_level_for_for ()
{
  current_binding_level->is_for_scope = 1;
}

void
pushlevel_temporary (tag_transparent)
     int tag_transparent;
{
  pushlevel (tag_transparent);
  current_binding_level->keep = 2;
  clear_last_expr ();

  /* Note we don't call push_momentary() here.  Otherwise, it would cause
     cleanups to be allocated on the momentary obstack, and they will be
     overwritten by the next statement.  */

  expand_start_bindings (0);
}

/* For a binding between a name and an entity at a block scope,
   this is the `struct binding_level' for the block.  */
#define BINDING_LEVEL(NODE) \
   (((struct tree_binding*)NODE)->scope.level)

/* Make DECL the innermost binding for ID.  The LEVEL is the binding
   level at which this declaration is being bound.  */

static void
push_binding (id, decl, level)
     tree id;
     tree decl;
     struct binding_level* level;
{
  tree binding;

  binding = make_node (CPLUS_BINDING);

  /* Now, fill in the binding information.  */
  BINDING_VALUE (binding) = decl;
  BINDING_TYPE (binding) = NULL_TREE;
  BINDING_LEVEL (binding) = level;
  INHERITED_VALUE_BINDING_P (binding) = 0;
  LOCAL_BINDING_P (binding) = (level != class_binding_level);
  BINDING_HAS_LEVEL_P (binding) = 1;

  /* And put it on the front of the list of bindings for ID.  */
  TREE_CHAIN (binding) = IDENTIFIER_BINDING (id);
  IDENTIFIER_BINDING (id) = binding;
}

/* ID is already bound in the current scope.  But, DECL is an
   additional binding for ID in the same scope.  This is the `struct
   stat' hack whereby a non-typedef class-name or enum-name can be
   bound at the same level as some other kind of entity.  It's the
   responsibility of the caller to check that inserting this name is
   legal here.  Returns nonzero if the new binding was successful.  */
static int
add_binding (id, decl)
     tree id;
     tree decl;
{
  tree binding = IDENTIFIER_BINDING (id);
  int ok = 1;

  if (TREE_CODE (decl) == TYPE_DECL && DECL_ARTIFICIAL (decl))
    /* The new name is the type name.  */
    BINDING_TYPE (binding) = decl;
  else if (!BINDING_VALUE (binding))
    /* This situation arises when push_class_level_binding moves an
       inherited type-binding out of the way to make room for a new
       value binding.  */
    BINDING_VALUE (binding) = decl;
  else if (TREE_CODE (BINDING_VALUE (binding)) == TYPE_DECL
           && DECL_ARTIFICIAL (BINDING_VALUE (binding)))
    {
      /* The old binding was a type name.  It was placed in
         BINDING_VALUE because it was thought, at the point it was
         declared, to be the only entity with such a name.  Move the
         type name into the type slot; it is now hidden by the new
         binding.  */
      BINDING_TYPE (binding) = BINDING_VALUE (binding);
      BINDING_VALUE (binding) = decl;
      INHERITED_VALUE_BINDING_P (binding) = 0;
    }
  else if (TREE_CODE (BINDING_VALUE (binding)) == TYPE_DECL
           && TREE_CODE (decl) == TYPE_DECL
           && DECL_NAME (decl) == DECL_NAME (BINDING_VALUE (binding))
           && same_type_p (TREE_TYPE (decl),
                           TREE_TYPE (BINDING_VALUE (binding))))
    /* We have two typedef-names, both naming the same type to have
       the same name.  This is OK because of:

         [dcl.typedef]

         In a given scope, a typedef specifier can be used to redefine
         the name of any type declared in that scope to refer to the
         type to which it already refers.  */
    ok = 0;
  else
    {
      cp_error ("declaration of `%#D'", decl);
      cp_error_at ("conflicts with previous declaration `%#D'",
                   BINDING_VALUE (binding));
      ok = 0;
    }

  return ok;
}

/* Add DECL to the list of things declared in B.  */

static void
add_decl_to_level (decl, b)
     tree decl;
     struct binding_level *b;
{
  /* We build up the list in reverse order, and reverse it later if
     necessary.  */
  TREE_CHAIN (decl) = b->names;
  b->names = decl;
}

/* Bind DECL to ID in the current_binding_level, assumed to be a local
   binding level.  If PUSH_USING is set in FLAGS, we know that DECL
   doesn't really belong to this binding level, that it got here
   through a using-declaration.  */

void
push_local_binding (id, decl, flags)
     tree id;
     tree decl;
     int flags;
{
  struct binding_level *b;

  /* Skip over any local classes.  This makes sense if we call
     push_local_binding with a friend decl of a local class.  */
  b = current_binding_level;
  while (b->parm_flag == 2)
    b = b->level_chain;

  if (lookup_name_current_level (id))
    {
      /* Supplement the existing binding.  */
      if (!add_binding (id, decl))
        /* It didn't work.  Something else must be bound at this
           level.  Do not add DECL to the list of things to pop
           later.  */
        return;
    }
  else
    /* Create a new binding.  */
    push_binding (id, decl, b);

  if (TREE_CODE (decl) == OVERLOAD || (flags & PUSH_USING))
    /* We must put the OVERLOAD into a TREE_LIST since the
       TREE_CHAIN of an OVERLOAD is already used.  Similarly for
       decls that got here through a using-declaration.  */
    decl = build_tree_list (NULL_TREE, decl);

  /* And put DECL on the list of things declared by the current
     binding level.  */
  add_decl_to_level (decl, b);
}

/* Bind DECL to ID in the class_binding_level.  Returns nonzero if the
   binding was successful.  */

int
push_class_binding (id, decl)
     tree id;
     tree decl;
{
  int result = 1;
  tree binding = IDENTIFIER_BINDING (id);
  tree context;

  /* Note that we declared this value so that we can issue an error if
     this an illegal redeclaration of a name already used for some
     other purpose.  */
  note_name_declared_in_class (id, decl);

  if (binding && BINDING_LEVEL (binding) == class_binding_level)
    /* Supplement the existing binding.  */
    result = add_binding (id, decl);
  else
    /* Create a new binding.  */
    push_binding (id, decl, class_binding_level);

  /* Update the IDENTIFIER_CLASS_VALUE for this ID to be the
     class-level declaration.  Note that we do not use DECL here
     because of the possibility of the `struct stat' hack; if DECL is
     a class-name or enum-name we might prefer a field-name, or some
     such.  */
  IDENTIFIER_CLASS_VALUE (id) = BINDING_VALUE (IDENTIFIER_BINDING (id));

  /* If this is a binding from a base class, mark it as such.  */
  binding = IDENTIFIER_BINDING (id);
  if (BINDING_VALUE (binding) == decl && TREE_CODE (decl) != TREE_LIST)
    {
      /* Any implicit typename must be from a base-class.  The
         context for an implicit typename declaration is always
         the derived class in which the lookup was done, so the checks
         based on the context of DECL below will not trigger.  */
      if (IMPLICIT_TYPENAME_TYPE_DECL_P (decl))
        INHERITED_VALUE_BINDING_P (binding) = 1;
      else
        {
          if (TREE_CODE (decl) == OVERLOAD)
            context = DECL_REAL_CONTEXT (OVL_CURRENT (decl));
          else
            {
              my_friendly_assert (TREE_CODE_CLASS (TREE_CODE (decl)) == 'd',
                                  0);
              context = DECL_REAL_CONTEXT (decl);
            }

          if (is_properly_derived_from (current_class_type, context))
            INHERITED_VALUE_BINDING_P (binding) = 1;
          else
            INHERITED_VALUE_BINDING_P (binding) = 0;
        }
    }
  else if (BINDING_VALUE (binding) == decl)
    /* We only encounter a TREE_LIST when push_class_decls detects an
       ambiguity.  Such an ambiguity can be overridden by a definition
       in this class.  */
    INHERITED_VALUE_BINDING_P (binding) = 1;

  return result;
}

/* Remove the binding for DECL which should be the innermost binding
   for ID.  */

static void 
pop_binding (id, decl) 
     tree id;
     tree decl;
{
  tree binding;
    
  if (id == NULL_TREE)
    /* It's easiest to write the loops that call this function without
       checking whether or not the entities involved have names.  We
       get here for such an entity.  */
    return;

  /* Get the innermost binding for ID.  */
  binding = IDENTIFIER_BINDING (id);

  /* The name should be bound.  */
  my_friendly_assert (binding != NULL_TREE, 0);

  /* The DECL will be either the ordinary binding or the type
     binding for this identifier.  Remove that binding.  */
  if (BINDING_VALUE (binding) == decl)
    BINDING_VALUE (binding) = NULL_TREE;
  else if (BINDING_TYPE (binding) == decl)
    BINDING_TYPE (binding) = NULL_TREE;
  else
    my_friendly_abort (0);

  if (!BINDING_VALUE (binding) && !BINDING_TYPE (binding))
    /* We're completely done with the innermost binding for this
       identifier.  Unhook it from the list of bindings.  */
    IDENTIFIER_BINDING (id) = TREE_CHAIN (binding);
}

/* When a label goes out of scope, check to see if that label was used
   in a valid manner, and issue any appropriate warnings or errors.  */

static void
pop_label (link)
     tree link;
{
  tree label = TREE_VALUE (link);

  if (!processing_template_decl && doing_semantic_analysis_p ())
    {
      if (DECL_INITIAL (label) == NULL_TREE)
        {
          cp_error_at ("label `%D' used but not defined", label);
          /* Avoid crashing later.  */
          define_label (input_filename, 1, DECL_NAME (label));
        }
      else if (warn_unused && !TREE_USED (label))
        cp_warning_at ("label `%D' defined but not used", label);
    }

  SET_IDENTIFIER_LABEL_VALUE (DECL_NAME (label), TREE_PURPOSE (link));
}

/* At the end of a function, all labels declared within the fucntion
   go out of scope.  BLOCK is the top-level block for the 
   function.  */

static void
pop_labels (block)
     tree block;
{
  tree link;

  /* Clear out the definitions of all label names, since their scopes
     end here.  */
  for (link = named_labels; link; link = TREE_CHAIN (link))
    {
      pop_label (link);
      /* Put the labels into the "variables" of the top-level block,
         so debugger can see them.  */
      TREE_CHAIN (TREE_VALUE (link)) = BLOCK_VARS (block);
      BLOCK_VARS (block) = TREE_VALUE (link);
    }

  named_labels = NULL_TREE;
}

/* Exit a binding level.
   Pop the level off, and restore the state of the identifier-decl mappings
   that were in effect when this level was entered.

   If KEEP == 1, this level had explicit declarations, so
   and create a "block" (a BLOCK node) for the level
   to record its declarations and subblocks for symbol table output.

   If FUNCTIONBODY is nonzero, this level is the body of a function,
   so create a block as if KEEP were set and also clear out all
   label names.

   If REVERSE is nonzero, reverse the order of decls before putting
   them into the BLOCK.  */

tree
poplevel (keep, reverse, functionbody)
     int keep;
     int reverse;
     int functionbody;
{
  register tree link;
  /* The chain of decls was accumulated in reverse order.
     Put it into forward order, just for cleanliness.  */
  tree decls;
  int tmp = functionbody;
  int real_functionbody;
  tree tags;
  tree subblocks;
  tree block = NULL_TREE;
  tree decl;
  int block_previously_created;
  int leaving_for_scope;

  if (current_function && !doing_semantic_analysis_p ())
    return NULL_TREE;

  my_friendly_assert (current_binding_level->parm_flag != 2,
                      19990916);

  real_functionbody = (current_binding_level->keep == 2
                       ? ((functionbody = 0), tmp) : functionbody);
  tags = functionbody >= 0 ? current_binding_level->tags : 0;
  subblocks = functionbody >= 0 ? current_binding_level->blocks : 0;

  my_friendly_assert (!current_binding_level->class_shadowed,
                      19990414);

  /* We used to use KEEP == 2 to indicate that the new block should go
     at the beginning of the list of blocks at this binding level,
     rather than the end.  This hack is no longer used.  */
  my_friendly_assert (keep == 0 || keep == 1, 0);

  GNU_xref_end_scope ((HOST_WIDE_INT) current_binding_level,
                      (HOST_WIDE_INT) current_binding_level->level_chain,
                      current_binding_level->parm_flag,
                      current_binding_level->keep);

  if (current_binding_level->keep == 1)
    keep = 1;

  /* Get the decls in the order they were written.
     Usually current_binding_level->names is in reverse order.
     But parameter decls were previously put in forward order.  */

  if (reverse)
    current_binding_level->names
      = decls = nreverse (current_binding_level->names);
  else
    decls = current_binding_level->names;

  /* Output any nested inline functions within this block
     if they weren't already output.  */

  for (decl = decls; decl; decl = TREE_CHAIN (decl))
    if (TREE_CODE (decl) == FUNCTION_DECL
        && ! TREE_ASM_WRITTEN (decl)
        && DECL_INITIAL (decl) != NULL_TREE
        && TREE_ADDRESSABLE (decl)
        && decl_function_context (decl) == current_function_decl)
      {
        /* If this decl was copied from a file-scope decl
           on account of a block-scope extern decl,
           propagate TREE_ADDRESSABLE to the file-scope decl.  */
        if (DECL_ABSTRACT_ORIGIN (decl) != NULL_TREE)
          TREE_ADDRESSABLE (DECL_ABSTRACT_ORIGIN (decl)) = 1;
        else
          {
            push_function_context ();
            output_inline_function (decl);
            pop_function_context ();
          }
      }

  /* If there were any declarations or structure tags in that level,
     or if this level is a function body,
     create a BLOCK to record them for the life of this function.  */

  block = NULL_TREE;
  block_previously_created = (current_binding_level->this_block != NULL_TREE);
  if (block_previously_created)
    block = current_binding_level->this_block;
  else if (keep == 1 || functionbody)
    block = make_node (BLOCK);
  if (block != NULL_TREE)
    {
      if (block_previously_created)
        {
          if (decls || tags || subblocks)
            {
              if (BLOCK_VARS (block) || BLOCK_TYPE_TAGS (block))
                warning ("internal compiler error: debugging info corrupted");

              BLOCK_VARS (block) = decls;
              BLOCK_TYPE_TAGS (block) = tags;

              /* We can have previous subblocks and new subblocks when
                 doing fixup_gotos with complex cleanups.  We chain the new
                 subblocks onto the end of any pre-existing subblocks.  */
              BLOCK_SUBBLOCKS (block) = chainon (BLOCK_SUBBLOCKS (block),
                                                 subblocks);
            }
          /* If we created the block earlier on, and we are just
             diddling it now, then it already should have a proper
             BLOCK_END_NOTE value associated with it.  */
        }
      else
        {
          BLOCK_VARS (block) = decls;
          BLOCK_TYPE_TAGS (block) = tags;
          BLOCK_SUBBLOCKS (block) = subblocks;
          /* Otherwise, for a new block, install a new BLOCK_END_NOTE
             value.  */ 
          remember_end_note (block);
        }
    }

  /* In each subblock, record that this is its superior.  */

  if (keep >= 0)
    for (link = subblocks; link; link = TREE_CHAIN (link))
      BLOCK_SUPERCONTEXT (link) = block;

  /* We still support the old for-scope rules, whereby the variables
     in a for-init statement were in scope after the for-statement
     ended.  We only use the new rules in flag_new_for_scope is
     nonzero.  */
  leaving_for_scope 
    = current_binding_level->is_for_scope && flag_new_for_scope == 1;

  /* Remove declarations for all the DECLs in this level.  */
  for (link = decls; link; link = TREE_CHAIN (link))
    {
      if (leaving_for_scope && TREE_CODE (link) == VAR_DECL)
        {
          tree outer_binding 
            = TREE_CHAIN (IDENTIFIER_BINDING (DECL_NAME (link)));
          tree ns_binding;

          if (!outer_binding)
            ns_binding = IDENTIFIER_NAMESPACE_VALUE (DECL_NAME (link));
          else
            ns_binding = NULL_TREE;

          if (outer_binding 
              && (BINDING_LEVEL (outer_binding) 
                  == current_binding_level->level_chain))
            /* We have something like:
               
                 int i;
                 for (int i; ;);
                 
               and we are leaving the `for' scope.  There's no reason to
               keep the binding of the inner `i' in this case.  */
            pop_binding (DECL_NAME (link), link);
          else if ((outer_binding 
                    && (TREE_CODE (BINDING_VALUE (outer_binding)) 
                        == TYPE_DECL))
                   || (ns_binding 
                       && TREE_CODE (ns_binding) == TYPE_DECL))
            /* Here, we have something like:

                 typedef int I;

                 void f () {
                   for (int I; ;);
                 }

               We must pop the for-scope binding so we know what's a
               type and what isn't.  */
            pop_binding (DECL_NAME (link), link);
          else
            {
              /* Mark this VAR_DECL as dead so that we can tell we left it
                 there only for backward compatibility.  */
              DECL_DEAD_FOR_LOCAL (link) = 1;
              
              /* Keep track of what should of have happenned when we
                 popped the binding.  */
              if (outer_binding && BINDING_VALUE (outer_binding))
                DECL_SHADOWED_FOR_VAR (link) 
                  = BINDING_VALUE (outer_binding);

              /* Add it to the list of dead variables in the next
                 outermost binding to that we can remove these when we
                 leave that binding.  */
              current_binding_level->level_chain->dead_vars_from_for
                = tree_cons (NULL_TREE, link,
                             current_binding_level->level_chain->
                             dead_vars_from_for);

              /* Although we don't pop the CPLUS_BINDING, we do clear
                 its BINDING_LEVEL since the level is going away now.  */
              BINDING_LEVEL (IDENTIFIER_BINDING (DECL_NAME (link)))
                = 0;
            }
        }
      else 
        {
          /* Remove the binding.  */
          decl = link;
          if (TREE_CODE (decl) == TREE_LIST)
            decl = TREE_VALUE (decl);
          if (TREE_CODE_CLASS (TREE_CODE (decl)) == 'd')
            pop_binding (DECL_NAME (decl), decl);
          else if (TREE_CODE (decl) == OVERLOAD)
            pop_binding (DECL_NAME (OVL_FUNCTION (decl)), decl);
          else 
            my_friendly_abort (0);
        }
    }

  /* Remove declarations for any `for' variables from inner scopes
     that we kept around.  */
  for (link = current_binding_level->dead_vars_from_for;
       link; link = TREE_CHAIN (link))
    pop_binding (DECL_NAME (TREE_VALUE (link)), TREE_VALUE (link));

  /* Restore the IDENTIFIER_TYPE_VALUEs.  */
  for (link = current_binding_level->type_shadowed;
       link; link = TREE_CHAIN (link))
    SET_IDENTIFIER_TYPE_VALUE (TREE_PURPOSE (link), TREE_VALUE (link));

  /* Restore the IDENTIFIER_LABEL_VALUEs for local labels.  */
  for (link = current_binding_level->shadowed_labels;
       link; 
       link = TREE_CHAIN (link))
    pop_label (link);

  /* There may be OVERLOADs (wrapped in TREE_LISTs) on the BLOCK_VARs
     list if a `using' declaration put them there.  The debugging
     back-ends won't understand OVERLOAD, so we remove them here.
     Because the BLOCK_VARS are (temporarily) shared with
     CURRENT_BINDING_LEVEL->NAMES we must do this fixup after we have
     popped all the bindings.  */
  if (block)
    {
      tree* d;

      for (d = &BLOCK_VARS (block); *d; )
        {
          if (TREE_CODE (*d) == TREE_LIST)
            *d = TREE_CHAIN (*d);
          else
            d = &TREE_CHAIN (*d);
        }
    }

  /* If the level being exited is the top level of a function,
     check over all the labels.  */
  if (functionbody)
    {
      /* Since this is the top level block of a function, the vars are
         the function's parameters.  Don't leave them in the BLOCK
         because they are found in the FUNCTION_DECL instead.  */
      BLOCK_VARS (block) = 0;
      pop_labels (block);
    }

  /* Any uses of undefined labels now operate under constraints
     of next binding contour.  */
  if (current_function)
    {
      struct binding_level *level_chain;
      level_chain = current_binding_level->level_chain;
      if (level_chain)
        {
          struct named_label_list *labels;
          for (labels = named_label_uses; labels; labels = labels->next)
            if (labels->binding_level == current_binding_level)
              {
                labels->binding_level = level_chain;
                labels->names_in_scope = level_chain->names;
              }
        }
    }

  tmp = current_binding_level->keep;

  pop_binding_level ();
  if (functionbody)
    DECL_INITIAL (current_function_decl) = block;
  else if (block)
    {
      if (!block_previously_created)
        current_binding_level->blocks
          = chainon (current_binding_level->blocks, block);
    }
  /* If we did not make a block for the level just exited,
     any blocks made for inner levels
     (since they cannot be recorded as subblocks in that level)
     must be carried forward so they will later become subblocks
     of something else.  */
  else if (subblocks)
    current_binding_level->blocks
      = chainon (current_binding_level->blocks, subblocks);

  /* Take care of compiler's internal binding structures.  */
  if (tmp == 2)
    {
      expand_end_bindings (getdecls (), keep, 1);
      /* Each and every BLOCK node created here in `poplevel' is important
         (e.g. for proper debugging information) so if we created one
         earlier, mark it as "used".  */
      if (block)
        TREE_USED (block) = 1;
      block = poplevel (keep, reverse, real_functionbody);
    }

  /* Each and every BLOCK node created here in `poplevel' is important
     (e.g. for proper debugging information) so if we created one
     earlier, mark it as "used".  */
  if (block)
    TREE_USED (block) = 1;
  return block;
}

/* Delete the node BLOCK from the current binding level.
   This is used for the block inside a stmt expr ({...})
   so that the block can be reinserted where appropriate.  */

void
delete_block (block)
     tree block;
{
  tree t;
  if (current_binding_level->blocks == block)
    current_binding_level->blocks = TREE_CHAIN (block);
  for (t = current_binding_level->blocks; t;)
    {
      if (TREE_CHAIN (t) == block)
        TREE_CHAIN (t) = TREE_CHAIN (block);
      else
        t = TREE_CHAIN (t);
    }
  TREE_CHAIN (block) = NULL_TREE;
  /* Clear TREE_USED which is always set by poplevel.
     The flag is set again if insert_block is called.  */
  TREE_USED (block) = 0;
}

/* Insert BLOCK at the end of the list of subblocks of the
   current binding level.  This is used when a BIND_EXPR is expanded,
   to handle the BLOCK node inside the BIND_EXPR.  */

void
insert_block (block)
     tree block;
{
  TREE_USED (block) = 1;
  current_binding_level->blocks
    = chainon (current_binding_level->blocks, block);
}

/* Set the BLOCK node for the innermost scope
   (the one we are currently in).  */

void
set_block (block)
    register tree block;
{
  current_binding_level->this_block = block;
}

/* Do a pushlevel for class declarations.  */

void
pushlevel_class ()
{
  register struct binding_level *newlevel;

  /* Reuse or create a struct for this binding level.  */
#if defined(DEBUG_CP_BINDING_LEVELS)
  if (0)
#else /* !defined(DEBUG_CP_BINDING_LEVELS) */
  if (free_binding_level)
#endif /* !defined(DEBUG_CP_BINDING_LEVELS) */
    {
      newlevel = free_binding_level;
      free_binding_level = free_binding_level->level_chain;
    }
  else
    newlevel = make_binding_level ();

#if defined(DEBUG_CP_BINDING_LEVELS)
  is_class_level = 1;
#endif /* defined(DEBUG_CP_BINDING_LEVELS) */

  push_binding_level (newlevel, 0, 0);

  class_binding_level = current_binding_level;
  class_binding_level->parm_flag = 2;
}

/* ...and a poplevel for class declarations.  */

void
poplevel_class ()
{
  register struct binding_level *level = class_binding_level;
  tree shadowed;

  my_friendly_assert (level != 0, 354);
  
  /* If we're leaving a toplevel class, don't bother to do the setting
     of IDENTIFIER_CLASS_VALUE to NULL_TREE, since first of all this slot
     shouldn't even be used when current_class_type isn't set, and second,
     if we don't touch it here, we're able to use the cache effect if the
     next time we're entering a class scope, it is the same class.  */
  if (current_class_depth != 1)
    {
      struct binding_level* b;

      /* Clear out our IDENTIFIER_CLASS_VALUEs.  */
      for (shadowed = level->class_shadowed;
           shadowed;
           shadowed = TREE_CHAIN (shadowed))
        IDENTIFIER_CLASS_VALUE (TREE_PURPOSE (shadowed)) = NULL_TREE;
        
      /* Find the next enclosing class, and recreate
         IDENTIFIER_CLASS_VALUEs appropriate for that class.  */
      b = level->level_chain;
      while (b && b->parm_flag != 2)
        b = b->level_chain;

      if (b)
        for (shadowed = b->class_shadowed; 
             shadowed; 
             shadowed = TREE_CHAIN (shadowed))
          {
            tree t;

            t = IDENTIFIER_BINDING (TREE_PURPOSE (shadowed));
            while (t && BINDING_LEVEL (t) != b)
              t = TREE_CHAIN (t);
      
            if (t)
              IDENTIFIER_CLASS_VALUE (TREE_PURPOSE (shadowed)) 
                = BINDING_VALUE (t);
          }
    }
  else
    /* Remember to save what IDENTIFIER's were bound in this scope so we
       can recover from cache misses.  */
    {
      previous_class_type = current_class_type;
      previous_class_values = class_binding_level->class_shadowed;
    }
  for (shadowed = level->type_shadowed;
       shadowed;
       shadowed = TREE_CHAIN (shadowed))
    SET_IDENTIFIER_TYPE_VALUE (TREE_PURPOSE (shadowed), TREE_VALUE (shadowed));

  /* Remove the bindings for all of the class-level declarations.  */
  for (shadowed = level->class_shadowed; 
       shadowed; 
       shadowed = TREE_CHAIN (shadowed))
    pop_binding (TREE_PURPOSE (shadowed), TREE_TYPE (shadowed));

  GNU_xref_end_scope ((HOST_WIDE_INT) class_binding_level,
                      (HOST_WIDE_INT) class_binding_level->level_chain,
                      class_binding_level->parm_flag,
                      class_binding_level->keep);

  /* Now, pop out of the binding level which we created up in the
     `pushlevel_class' routine.  */
#if defined(DEBUG_CP_BINDING_LEVELS)
  is_class_level = 1;
#endif /* defined(DEBUG_CP_BINDING_LEVELS) */

  pop_binding_level ();
}

/* We are entering the scope of a class.  Clear IDENTIFIER_CLASS_VALUE
   for any names in enclosing classes.  */

void
clear_identifier_class_values ()
{
  tree t;

  if (!class_binding_level)
    return;

  for (t = class_binding_level->class_shadowed;
       t;
       t = TREE_CHAIN (t))
    IDENTIFIER_CLASS_VALUE (TREE_PURPOSE (t)) = NULL_TREE;
}

/* Returns non-zero if T is a virtual function table.  */

int
vtable_decl_p (t, data)
     tree t;
     void *data ATTRIBUTE_UNUSED;
{
  return (TREE_CODE (t) == VAR_DECL && DECL_VIRTUAL_P (t));
}

/* Returns non-zero if T is a TYPE_DECL for a type with virtual
   functions.  */

int
vtype_decl_p (t, data)
     tree t;
     void *data ATTRIBUTE_UNUSED;
{
  return (TREE_CODE (t) == TYPE_DECL
          && TREE_TYPE (t) != error_mark_node
          && TYPE_LANG_SPECIFIC (TREE_TYPE (t))
          && CLASSTYPE_VSIZE (TREE_TYPE (t)));
}

/* Return the declarations that are members of the namespace NS.  */

tree
cp_namespace_decls (ns)
     tree ns;
{
  return NAMESPACE_LEVEL (ns)->names;
}

/* Walk all the namespaces contained NAMESPACE, including NAMESPACE
   itself, calling F for each.  The DATA is passed to F as well.  */

static int
walk_namespaces_r (namespace, f, data)
     tree namespace;
     walk_namespaces_fn f;
     void *data;
{
  tree current;
  int result = 0;

  result |= (*f) (namespace, data);

  for (current = cp_namespace_decls (namespace);
       current;
       current = TREE_CHAIN (current))
    {
      if (TREE_CODE (current) != NAMESPACE_DECL
          || DECL_NAMESPACE_ALIAS (current))
        continue;
      if (!DECL_LANG_SPECIFIC (current))
        {
          /* Hmm. std. */
          my_friendly_assert (current == std_node, 393);
          continue;
        }

      /* We found a namespace.  */
      result |= walk_namespaces_r (current, f, data);
    }

  return result;
}

/* Walk all the namespaces, calling F for each.  The DATA is passed to
   F as well.  */

int
walk_namespaces (f, data)
     walk_namespaces_fn f;
     void *data;
{
  return walk_namespaces_r (global_namespace, f, data);
}

struct walk_globals_data {
  walk_globals_pred p;
  walk_globals_fn f;
  void *data;
};

/* Walk the global declarations in NAMESPACE.  Whenever one is found
   for which P returns non-zero, call F with its address.  If any call
   to F returns a non-zero value, return a non-zero value.  */

static int 
walk_globals_r (namespace, data)
     tree namespace;
     void *data;
{
  struct walk_globals_data* wgd = (struct walk_globals_data *) data;
  walk_globals_pred p = wgd->p;
  walk_globals_fn f = wgd->f;
  void *d = wgd->data;
  tree *t;
  int result = 0;

  t = &NAMESPACE_LEVEL (namespace)->names;

  while (*t)
    {
      tree glbl = *t;

      if ((*p) (glbl, d))
        result |= (*f) (t, d);

      /* If F changed *T, then *T still points at the next item to
         examine.  */
      if (*t == glbl)
        t = &TREE_CHAIN (*t);
    }

  return result;
}

/* Walk the global declarations.  Whenever one is found for which P
   returns non-zero, call F with its address.  If any call to F
   returns a non-zero value, return a non-zero value.  */

int
walk_globals (p, f, data)
     walk_globals_pred p;
     walk_globals_fn f;
     void *data;
{
  struct walk_globals_data wgd;
  wgd.p = p;
  wgd.f = f;
  wgd.data = data;

  return walk_namespaces (walk_globals_r, &wgd);
}

/* Call wrapup_globals_declarations for the globals in NAMESPACE.  If
   DATA is non-NULL, this is the last time we will call
   wrapup_global_declarations for this NAMESPACE.  */

int
wrapup_globals_for_namespace (namespace, data)
     tree namespace;
     void *data;
{
  tree globals = cp_namespace_decls (namespace);
  int len = list_length (globals);
  tree *vec = (tree *) alloca (sizeof (tree) * len);
  int i;
  int result;
  tree decl;
  int last_time = (data != 0);

  if (last_time && namespace == global_namespace)
    /* Let compile_file handle the global namespace.  */
    return 0;

  /* Process the decls in reverse order--earliest first.
     Put them into VEC from back to front, then take out from front.  */
  
  for (i = 0, decl = globals; i < len; i++, decl = TREE_CHAIN (decl))
    vec[len - i - 1] = decl;
  
  if (last_time)
    {
      check_global_declarations (vec, len);
      return 0;
    }

  /* Temporarily mark vtables as external.  That prevents
     wrapup_global_declarations from writing them out; we must process
     them ourselves in finish_vtable_vardecl.  */
  for (i = 0; i < len; ++i)
    if (vtable_decl_p (vec[i], /*data=*/0) && !DECL_EXTERNAL (vec[i]))
      {
        DECL_NOT_REALLY_EXTERN (vec[i]) = 1;
        DECL_EXTERNAL (vec[i]) = 1;
      }

  /* Write out any globals that need to be output.  */
  result = wrapup_global_declarations (vec, len);

  /* Undo the hack to DECL_EXTERNAL above.  */
  for (i = 0; i < len; ++i)
    if (vtable_decl_p (vec[i], /*data=*/0)
        && DECL_NOT_REALLY_EXTERN (vec[i]))
      {
        DECL_NOT_REALLY_EXTERN (vec[i]) = 0;
        DECL_EXTERNAL (vec[i]) = 0;
      }

  return result;
}

\f
/* Mark ARG (which is really a struct binding_level **) for GC.  */

static void
mark_binding_level (arg)
     void *arg;
{
  struct binding_level *lvl = *(struct binding_level **)arg;

  while (lvl)
    {
      ggc_mark_tree (lvl->names);
      ggc_mark_tree (lvl->tags);
      ggc_mark_tree (lvl->usings);
      ggc_mark_tree (lvl->using_directives);
      ggc_mark_tree (lvl->class_shadowed);
      ggc_mark_tree (lvl->type_shadowed);
      ggc_mark_tree (lvl->shadowed_labels);
      ggc_mark_tree (lvl->blocks);
      ggc_mark_tree (lvl->this_block);
      ggc_mark_tree (lvl->incomplete);
      ggc_mark_tree (lvl->dead_vars_from_for);

      lvl = lvl->level_chain;
    }
}
\f
/* For debugging.  */
static int no_print_functions = 0;
static int no_print_builtins = 0;

void
print_binding_level (lvl)
     struct binding_level *lvl;
{
  tree t;
  int i = 0, len;
  fprintf (stderr, " blocks=");
  fprintf (stderr, HOST_PTR_PRINTF, lvl->blocks);
  fprintf (stderr, " n_incomplete=%d parm_flag=%d keep=%d",
           list_length (lvl->incomplete), lvl->parm_flag, lvl->keep);
  if (lvl->tag_transparent)
    fprintf (stderr, " tag-transparent");
  if (lvl->more_cleanups_ok)
    fprintf (stderr, " more-cleanups-ok");
  if (lvl->have_cleanups)
    fprintf (stderr, " have-cleanups");
  fprintf (stderr, "\n");
  if (lvl->names)
    {
      fprintf (stderr, " names:\t");
      /* We can probably fit 3 names to a line?  */
      for (t = lvl->names; t; t = TREE_CHAIN (t))
        {
          if (no_print_functions && (TREE_CODE (t) == FUNCTION_DECL)) 
            continue;
          if (no_print_builtins
              && (TREE_CODE (t) == TYPE_DECL)
              && (!strcmp (DECL_SOURCE_FILE (t),"<built-in>")))
            continue;

          /* Function decls tend to have longer names.  */
          if (TREE_CODE (t) == FUNCTION_DECL)
            len = 3;
          else
            len = 2;
          i += len;
          if (i > 6)
            {
              fprintf (stderr, "\n\t");
              i = len;
            }
          print_node_brief (stderr, "", t, 0);
          if (t == error_mark_node)
            break;
        }
      if (i)
        fprintf (stderr, "\n");
    }
  if (lvl->tags)
    {
      fprintf (stderr, " tags:\t");
      i = 0;
      for (t = lvl->tags; t; t = TREE_CHAIN (t))
        {
          if (TREE_PURPOSE (t) == NULL_TREE)
            len = 3;
          else if (TREE_PURPOSE (t) == TYPE_IDENTIFIER (TREE_VALUE (t)))
            len = 2;
          else
            len = 4;
          i += len;
          if (i > 5)
            {
              fprintf (stderr, "\n\t");
              i = len;
            }
          if (TREE_PURPOSE (t) == NULL_TREE)
            {
              print_node_brief (stderr, "<unnamed-typedef", TREE_VALUE (t), 0);
              fprintf (stderr, ">");
            }
          else if (TREE_PURPOSE (t) == TYPE_IDENTIFIER (TREE_VALUE (t)))
            print_node_brief (stderr, "", TREE_VALUE (t), 0);
          else
            {
              print_node_brief (stderr, "<typedef", TREE_PURPOSE (t), 0);
              print_node_brief (stderr, "", TREE_VALUE (t), 0);
              fprintf (stderr, ">");
            }
        }
      if (i)
        fprintf (stderr, "\n");
    }
  if (lvl->class_shadowed)
    {
      fprintf (stderr, " class-shadowed:");
      for (t = lvl->class_shadowed; t; t = TREE_CHAIN (t))
        {
          fprintf (stderr, " %s ", IDENTIFIER_POINTER (TREE_PURPOSE (t)));
        }
      fprintf (stderr, "\n");
    }
  if (lvl->type_shadowed)
    {
      fprintf (stderr, " type-shadowed:");
      for (t = lvl->type_shadowed; t; t = TREE_CHAIN (t))
        {
          fprintf (stderr, " %s ", IDENTIFIER_POINTER (TREE_PURPOSE (t)));
        }
      fprintf (stderr, "\n");
    }
}

void
print_other_binding_stack (stack)
     struct binding_level *stack;
{
  struct binding_level *level;
  for (level = stack; level != global_binding_level; level = level->level_chain)
    {
      fprintf (stderr, "binding level ");
      fprintf (stderr, HOST_PTR_PRINTF, level);
      fprintf (stderr, "\n");
      print_binding_level (level);
    }
}

void
print_binding_stack ()
{
  struct binding_level *b;
  fprintf (stderr, "current_binding_level=");
  fprintf (stderr, HOST_PTR_PRINTF, current_binding_level);
  fprintf (stderr, "\nclass_binding_level=");
  fprintf (stderr, HOST_PTR_PRINTF, class_binding_level);
  fprintf (stderr, "\nglobal_binding_level=");
  fprintf (stderr, HOST_PTR_PRINTF, global_binding_level);
  fprintf (stderr, "\n");
  if (class_binding_level)
    {
      for (b = class_binding_level; b; b = b->level_chain)
        if (b == current_binding_level)
          break;
      if (b)
        b = class_binding_level;
      else
        b = current_binding_level;
    }
  else
    b = current_binding_level;
  print_other_binding_stack (b);
  fprintf (stderr, "global:\n");
  print_binding_level (global_binding_level);
}

/* Namespace binding access routines: The namespace_bindings field of
   the identifier is polymorphic, with three possible values:
   NULL_TREE, a list of CPLUS_BINDINGS, or any other tree_node
   indicating the BINDING_VALUE of global_namespace. */

/* Check whether the a binding for the name to scope is known.
   Assumes that the bindings of the name are already a list
   of bindings. Returns the binding found, or NULL_TREE. */

static tree
find_binding (name, scope)
     tree name;
     tree scope;
{
  tree iter, prev = NULL_TREE;

  scope = ORIGINAL_NAMESPACE (scope);
  
  for (iter = IDENTIFIER_NAMESPACE_BINDINGS (name); iter;
       iter = TREE_CHAIN (iter))
    {
      my_friendly_assert (TREE_CODE (iter) == CPLUS_BINDING, 374);
      if (BINDING_SCOPE (iter) == scope)
        {
          /* Move binding found to the front of the list, so
             subsequent lookups will find it faster. */
          if (prev)
            {
              TREE_CHAIN (prev) = TREE_CHAIN (iter);
              TREE_CHAIN (iter) = IDENTIFIER_NAMESPACE_BINDINGS (name);
              IDENTIFIER_NAMESPACE_BINDINGS (name) = iter;
            }
          return iter;
        }
      prev = iter;
    }
  return NULL_TREE;
}

/* Always returns a binding for name in scope. If the
   namespace_bindings is not a list, convert it to one first.
   If no binding is found, make a new one. */

tree
binding_for_name (name, scope)
     tree name;
     tree scope;
{
  tree b = IDENTIFIER_NAMESPACE_BINDINGS (name);
  tree result;

  scope = ORIGINAL_NAMESPACE (scope);
  
  if (b && TREE_CODE (b) != CPLUS_BINDING)
    {
      /* Get rid of optimization for global scope. */
      IDENTIFIER_NAMESPACE_BINDINGS (name) = NULL_TREE;
      BINDING_VALUE (binding_for_name (name, global_namespace)) = b;
      b = IDENTIFIER_NAMESPACE_BINDINGS (name);
    }
  if (b && (result = find_binding (name, scope)))
    return result;
  /* Not found, make a new permanent one. */
  push_obstacks (&permanent_obstack, &permanent_obstack);
  result = make_node (CPLUS_BINDING);
  TREE_CHAIN (result) = b;
  IDENTIFIER_NAMESPACE_BINDINGS (name) = result;
  BINDING_SCOPE (result) = scope;
  BINDING_TYPE (result) = NULL_TREE;
  BINDING_VALUE (result) = NULL_TREE;
  pop_obstacks ();
  return result;
}

/* Return the binding value for name in scope, considering that
   namespace_binding may or may not be a list of CPLUS_BINDINGS. */

tree
namespace_binding (name, scope)
     tree name;
     tree scope;
{
  tree b = IDENTIFIER_NAMESPACE_BINDINGS (name);
  if (b == NULL_TREE)
    return NULL_TREE;
  if (scope == NULL_TREE)
    scope = global_namespace;
  if (TREE_CODE (b) != CPLUS_BINDING)
    return (scope == global_namespace) ? b : NULL_TREE;
  name = find_binding (name,scope);
  if (name == NULL_TREE)
    return name;
  return BINDING_VALUE (name);
}

/* Set the binding value for name in scope. If modifying the binding
   of global_namespace is attempted, try to optimize it. */

void
set_namespace_binding (name, scope, val)
     tree name;
     tree scope;
     tree val;
{
  tree b;

  if (scope == NULL_TREE)
    scope = global_namespace;
  
  if (scope == global_namespace)
    {
      b = IDENTIFIER_NAMESPACE_BINDINGS (name);
      if (b == NULL_TREE || TREE_CODE (b) != CPLUS_BINDING)
        {
          IDENTIFIER_NAMESPACE_BINDINGS (name) = val;
          return;
        }
    }
  b = binding_for_name (name, scope);
  BINDING_VALUE (b) = val;
}

/* Push into the scope of the NAME namespace.  If NAME is NULL_TREE, then we
   select a name that is unique to this compilation unit.  */

void
push_namespace (name)
     tree name;
{
  tree d = NULL_TREE;
  int need_new = 1;
  int implicit_use = 0;
  int global = 0;
  if (!global_namespace)
    {
      /* This must be ::. */
      my_friendly_assert (name == get_identifier ("::"), 377);
      global = 1;
    }
  else if (!name)
    {
      /* The name of anonymous namespace is unique for the translation
         unit.  */
      if (!anonymous_namespace_name)
        anonymous_namespace_name = get_file_function_name ('N');
      name = anonymous_namespace_name;
      d = IDENTIFIER_NAMESPACE_VALUE (name);
      if (d)
        /* Reopening anonymous namespace.  */
        need_new = 0;
      implicit_use = 1;
    }
  else if (current_namespace == global_namespace
           && name == DECL_NAME (std_node))
    {
      in_std++;
      return;
    }
  else
    {
      /* Check whether this is an extended namespace definition. */
      d = IDENTIFIER_NAMESPACE_VALUE (name);
      if (d != NULL_TREE && TREE_CODE (d) == NAMESPACE_DECL)
        {
          need_new = 0;
          if (DECL_NAMESPACE_ALIAS (d))
            {
              cp_error ("namespace alias `%D' not allowed here, assuming `%D'",
                        d, DECL_NAMESPACE_ALIAS (d));
              d = DECL_NAMESPACE_ALIAS (d);
            }
        }
    }
  
  if (need_new)
    {
      /* Make a new namespace, binding the name to it. */
      d = build_lang_decl (NAMESPACE_DECL, name, void_type_node);
      /* The global namespace is not pushed, and the global binding
         level is set elsewhere.  */
      if (!global)
        {
          d = pushdecl (d);
          pushlevel (0);
          declare_namespace_level ();
          NAMESPACE_LEVEL (d) = current_binding_level;
        }
    }
  else
    resume_binding_level (NAMESPACE_LEVEL (d));

  if (implicit_use)
    do_using_directive (d);
  /* Enter the name space. */
  current_namespace = d;
}

/* Pop from the scope of the current namespace.  */

void
pop_namespace ()
{
  if (current_namespace == global_namespace)
    {
      my_friendly_assert (in_std>0, 980421);
      in_std--;
      return;
    }
  current_namespace = CP_DECL_CONTEXT (current_namespace);
  /* The binding level is not popped, as it might be re-opened later.  */
  suspend_binding_level ();
}

/* Push into the scope of the namespace NS, even if it is deeply
   nested within another namespace.  */

void
push_nested_namespace (ns)
     tree ns;
{
  if (ns == global_namespace)
    push_to_top_level ();
  else
    {
      push_nested_namespace (CP_DECL_CONTEXT (ns));
      push_namespace (DECL_NAME (ns));
    }
}

/* Pop back from the scope of the namespace NS, which was previously
   entered with push_nested_namespace.  */
     
void
pop_nested_namespace (ns)
     tree ns;
{
  while (ns != global_namespace)
    {
      pop_namespace ();
      ns = CP_DECL_CONTEXT (ns);
    }

  pop_from_top_level ();
}

\f
/* Subroutines for reverting temporarily to top-level for instantiation
   of templates and such.  We actually need to clear out the class- and
   local-value slots of all identifiers, so that only the global values
   are at all visible.  Simply setting current_binding_level to the global
   scope isn't enough, because more binding levels may be pushed.  */
struct saved_scope *scope_chain;

/* Mark ARG (which is really a struct saved_scope **) for GC.  */

static void
mark_saved_scope (arg)
     void *arg;
{
  struct saved_scope *t = *(struct saved_scope **)arg;
  while (t)
    {
      mark_binding_level (&t->class_bindings);
      ggc_mark_tree (t->old_bindings);
      ggc_mark_tree (t->old_namespace);
      ggc_mark_tree (t->class_name);
      ggc_mark_tree (t->class_type);
      ggc_mark_tree (t->access_specifier);
      ggc_mark_tree (t->function_decl);
      if (t->lang_base)
        ggc_mark_tree_varray (t->lang_base);
      ggc_mark_tree (t->lang_name);
      ggc_mark_tree (t->x_function_parms);
      ggc_mark_tree (t->template_parms);
      ggc_mark_tree (t->x_previous_class_type);
      ggc_mark_tree (t->x_previous_class_values);
      mark_binding_level (&t->bindings);
      t = t->prev;
    }
}

static tree
store_bindings (names, old_bindings)
     tree names, old_bindings;
{
  tree t;
  for (t = names; t; t = TREE_CHAIN (t))
    {
      tree binding, t1, id;

      if (TREE_CODE (t) == TREE_LIST)
        id = TREE_PURPOSE (t);
      else
        id = DECL_NAME (t);

      if (!id 
          /* Note that we may have an IDENTIFIER_CLASS_VALUE even when
             we have no IDENTIFIER_BINDING if we have left the class
             scope, but cached the class-level declarations.  */
          || !(IDENTIFIER_BINDING (id) || IDENTIFIER_CLASS_VALUE (id)))
        continue;

      for (t1 = old_bindings; t1; t1 = TREE_CHAIN (t1))
        if (TREE_VEC_ELT (t1, 0) == id)
          goto skip_it;

      binding = make_tree_vec (4);

      if (id)
        {
          my_friendly_assert (TREE_CODE (id) == IDENTIFIER_NODE, 135);
          TREE_VEC_ELT (binding, 0) = id;
          TREE_VEC_ELT (binding, 1) = REAL_IDENTIFIER_TYPE_VALUE (id);
          TREE_VEC_ELT (binding, 2) = IDENTIFIER_BINDING (id);
          TREE_VEC_ELT (binding, 3) = IDENTIFIER_CLASS_VALUE (id);
          IDENTIFIER_BINDING (id) = NULL_TREE;
          IDENTIFIER_CLASS_VALUE (id) = NULL_TREE;
        }
      TREE_CHAIN (binding) = old_bindings;
      old_bindings = binding;
    skip_it:
      ;
    }
  return old_bindings;
}

void
maybe_push_to_top_level (pseudo)
     int pseudo;
{
  struct saved_scope *s;
  struct binding_level *b;
  tree old_bindings;
  int need_pop;

  s = (struct saved_scope *) xcalloc (1, sizeof (struct saved_scope));

  b = scope_chain ? current_binding_level : 0;

  /* If we're in the middle of some function, save our state.  */
  if (current_function)
    {
      need_pop = 1;
      push_function_context_to (NULL_TREE);
    }
  else
    need_pop = 0;

  old_bindings = NULL_TREE;
  if (scope_chain && previous_class_type)
    old_bindings = store_bindings (previous_class_values, old_bindings);

  /* Have to include global_binding_level, because class-level decls
     aren't listed anywhere useful.  */
  for (; b; b = b->level_chain)
    {
      tree t;

      /* Template IDs are inserted into the global level. If they were
         inserted into namespace level, finish_file wouldn't find them
         when doing pending instantiations. Therefore, don't stop at
         namespace level, but continue until :: .  */
      if (b == global_binding_level || (pseudo && b->pseudo_global))
        break;

      old_bindings = store_bindings (b->names, old_bindings);
      /* We also need to check class_shadowed to save class-level type
         bindings, since pushclass doesn't fill in b->names.  */
      if (b->parm_flag == 2)
        old_bindings = store_bindings (b->class_shadowed, old_bindings);

      /* Unwind type-value slots back to top level.  */
      for (t = b->type_shadowed; t; t = TREE_CHAIN (t))
        SET_IDENTIFIER_TYPE_VALUE (TREE_PURPOSE (t), TREE_VALUE (t));
    }
  s->prev = scope_chain;
  s->old_bindings = old_bindings;
  s->bindings = b;
  s->need_pop_function_context = need_pop;
  s->function_decl = current_function_decl;

  scope_chain = s;
  current_function_decl = NULL_TREE;
  VARRAY_TREE_INIT (current_lang_base, 10, "current_lang_base");
  current_lang_stack = &VARRAY_TREE (current_lang_base, 0);
  current_lang_name = lang_name_cplusplus;
  strict_prototype = strict_prototypes_lang_cplusplus;
  current_namespace = global_namespace;

  push_obstacks (&permanent_obstack, &permanent_obstack);
}

void
push_to_top_level ()
{
  maybe_push_to_top_level (0);
}

void
pop_from_top_level ()
{
  struct saved_scope *s = scope_chain;
  tree t;

  /* Clear out class-level bindings cache.  */
  if (previous_class_type)
    invalidate_class_lookup_cache ();

  pop_obstacks ();

  VARRAY_FREE (current_lang_base);

  scope_chain = s->prev;
  for (t = s->old_bindings; t; t = TREE_CHAIN (t))
    {
      tree id = TREE_VEC_ELT (t, 0);
      if (id)
        {
          SET_IDENTIFIER_TYPE_VALUE (id, TREE_VEC_ELT (t, 1));
          IDENTIFIER_BINDING (id) = TREE_VEC_ELT (t, 2);
          IDENTIFIER_CLASS_VALUE (id) = TREE_VEC_ELT (t, 3);
        }
    }

  if (current_lang_name == lang_name_cplusplus)
    strict_prototype = strict_prototypes_lang_cplusplus;
  else if (current_lang_name == lang_name_c)
    strict_prototype = strict_prototypes_lang_c;

  /* If we were in the middle of compiling a function, restore our
     state.  */
  if (s->need_pop_function_context)
    pop_function_context_from (NULL_TREE);
  current_function_decl = s->function_decl;

  free (s);
}
\f
/* Push a definition of struct, union or enum tag "name".
   into binding_level "b".   "type" should be the type node, 
   We assume that the tag "name" is not already defined.

   Note that the definition may really be just a forward reference.
   In that case, the TYPE_SIZE will be a NULL_TREE.

   C++ gratuitously puts all these tags in the name space.  */

/* When setting the IDENTIFIER_TYPE_VALUE field of an identifier ID,
   record the shadowed value for this binding contour.  TYPE is
   the type that ID maps to.  */

static void
set_identifier_type_value_with_scope (id, type, b)
     tree id;
     tree type;
     struct binding_level *b;
{
  if (!b->namespace_p)
    {
      /* Shadow the marker, not the real thing, so that the marker
         gets restored later. */
      tree old_type_value = REAL_IDENTIFIER_TYPE_VALUE (id);
      b->type_shadowed
        = tree_cons (id, old_type_value, b->type_shadowed);
    }
  else
    {
      tree binding = binding_for_name (id, current_namespace);
      BINDING_TYPE (binding) = type;
      /* Store marker instead of real type. */
      type = global_type_node;
    }
  SET_IDENTIFIER_TYPE_VALUE (id, type);
}

/* As set_identifier_type_value_with_scope, but using current_binding_level.  */

void
set_identifier_type_value (id, type)
     tree id;
     tree type;
{
  set_identifier_type_value_with_scope (id, type, current_binding_level);
}

/* Return the type associated with id. */

tree
identifier_type_value (id)
     tree id;
{
  /* There is no type with that name, anywhere. */
  if (REAL_IDENTIFIER_TYPE_VALUE (id) == NULL_TREE)
    return NULL_TREE;
  /* This is not the type marker, but the real thing. */
  if (REAL_IDENTIFIER_TYPE_VALUE (id) != global_type_node)
    return REAL_IDENTIFIER_TYPE_VALUE (id);
  /* Have to search for it. It must be on the global level, now.
     Ask lookup_name not to return non-types. */
  id = lookup_name_real (id, 2, 1, 0);
  if (id)
    return TREE_TYPE (id);
  return NULL_TREE;
}

/* Pop off extraneous binding levels left over due to syntax errors.

   We don't pop past namespaces, as they might be valid.  */

void
pop_everything ()
{
#ifdef DEBUG_CP_BINDING_LEVELS
  fprintf (stderr, "XXX entering pop_everything ()\n");
#endif
  while (!toplevel_bindings_p ())
    {
      if (current_binding_level->parm_flag == 2)
        pop_nested_class ();
      else
        poplevel (0, 0, 0);
    }
#ifdef DEBUG_CP_BINDING_LEVELS
  fprintf (stderr, "XXX leaving pop_everything ()\n");
#endif
}

/* The type TYPE is being declared.  If it is a class template, or a
   specialization of a class template, do any processing required and
   perform error-checking.  If IS_FRIEND is non-zero, this TYPE is
   being declared a friend.  B is the binding level at which this TYPE
   should be bound.

   Returns the TYPE_DECL for TYPE, which may have been altered by this
   processing.  */

static tree 
maybe_process_template_type_declaration (type, globalize, b)
     tree type;
     int globalize;
     struct binding_level* b;
{
  tree decl = TYPE_NAME (type);
 
  if (processing_template_parmlist)
    /* You can't declare a new template type in a template parameter
       list.  But, you can declare a non-template type:
       
         template <class A*> struct S;
       
       is a forward-declaration of `A'.  */
    ;
  else 
    {
      maybe_check_template_type (type);

      my_friendly_assert (IS_AGGR_TYPE (type) 
                          || TREE_CODE (type) == ENUMERAL_TYPE, 0);
                          
                          
      if (processing_template_decl)
        {
          /* This may change after the call to
             push_template_decl_real, but we want the original value.  */
          tree name = DECL_NAME (decl);

          decl = push_template_decl_real (decl, globalize);
          /* If the current binding level is the binding level for the
             template parameters (see the comment in
             begin_template_parm_list) and the enclosing level is a class
             scope, and we're not looking at a friend, push the
             declaration of the member class into the class scope.  In the
             friend case, push_template_decl will already have put the
             friend into global scope, if appropriate.  */
          if (TREE_CODE (type) != ENUMERAL_TYPE
              && !globalize && b->pseudo_global
              && b->level_chain->parm_flag == 2)
            {
              finish_member_declaration (CLASSTYPE_TI_TEMPLATE (type));
              /* Put this tag on the list of tags for the class, since
                 that won't happen below because B is not the class
                 binding level, but is instead the pseudo-global level.  */
              b->level_chain->tags = 
                tree_cons (name, type, b->level_chain->tags);
              if (TYPE_SIZE (current_class_type) == NULL_TREE)
                CLASSTYPE_TAGS (current_class_type) = b->level_chain->tags;
            }
        }
    }

  return decl;
}

/* In C++, you don't have to write `struct S' to refer to `S'; you
   can just use `S'.  We accomplish this by creating a TYPE_DECL as
   if the user had written `typedef struct S S'.  Create and return
   the TYPE_DECL for TYPE.  */

tree
create_implicit_typedef (name, type)
     tree name;
     tree type;
{
  tree decl;

  decl = build_decl (TYPE_DECL, name, type);
  SET_DECL_ARTIFICIAL (decl);
  /* There are other implicit type declarations, like the one *within*
     a class that allows you to write `S::S'.  We must distinguish
     amongst these.  */
  SET_DECL_IMPLICIT_TYPEDEF_P (decl);
  TYPE_NAME (type) = decl;

  return decl;
}

/* Push a tag name NAME for struct/class/union/enum type TYPE.
   Normally put it into the inner-most non-tag-transparent scope,
   but if GLOBALIZE is true, put it in the inner-most non-class scope.
   The latter is needed for implicit declarations.  */

void
pushtag (name, type, globalize)
     tree name, type;
     int globalize;
{
  register struct binding_level *b;

  b = current_binding_level;
  while (b->tag_transparent
         || (globalize && b->parm_flag == 2))
    b = b->level_chain;

  b->tags = tree_cons (name, type, b->tags);

  if (name)
    {
      /* Do C++ gratuitous typedefing.  */
      if (IDENTIFIER_TYPE_VALUE (name) != type)
        {
          register tree d = NULL_TREE;
          int in_class = 0;
          tree context = TYPE_CONTEXT (type);

          if (! context)
            {
              tree cs = current_scope ();

              if (! globalize)
                context = cs;
              else if (cs != NULL_TREE 
                       && TREE_CODE_CLASS (TREE_CODE (cs)) == 't')
                /* When declaring a friend class of a local class, we want
                   to inject the newly named class into the scope
                   containing the local class, not the namespace scope.  */
                context = hack_decl_function_context (get_type_decl (cs));
            }
          if (!context)
            context = current_namespace;

          if ((b->pseudo_global && b->level_chain->parm_flag == 2)
              || b->parm_flag == 2)
            in_class = 1;

          if (current_lang_name == lang_name_java)
            TYPE_FOR_JAVA (type) = 1;

          d = create_implicit_typedef (name, type);
          DECL_CONTEXT (d) = FROB_CONTEXT (context);
          if (! in_class)
            set_identifier_type_value_with_scope (name, type, b);

          d = maybe_process_template_type_declaration (type,
                                                       globalize, b);

          if (b->parm_flag == 2)
            {
              if (!PROCESSING_REAL_TEMPLATE_DECL_P ())
                /* Put this TYPE_DECL on the TYPE_FIELDS list for the
                   class.  But if it's a member template class, we
                   want the TEMPLATE_DECL, not the TYPE_DECL, so this
                   is done later.  */
                finish_member_declaration (d);
              else
                pushdecl_class_level (d);
            }
          else
            d = pushdecl_with_scope (d, b);

          if (ANON_AGGRNAME_P (name))
            DECL_IGNORED_P (d) = 1;

          TYPE_CONTEXT (type) = DECL_CONTEXT (d);
          DECL_ASSEMBLER_NAME (d) = DECL_NAME (d);
          if (!uses_template_parms (type))
            DECL_ASSEMBLER_NAME (d)
              = get_identifier (build_overload_name (type, 1, 1));
        }
      if (b->parm_flag == 2)
        {
          if (TYPE_SIZE (current_class_type) == NULL_TREE)
            CLASSTYPE_TAGS (current_class_type) = b->tags;
        }
    }

  if (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL)
    /* Use the canonical TYPE_DECL for this node.  */
    TYPE_STUB_DECL (type) = TYPE_NAME (type);
  else
    {
      /* Create a fake NULL-named TYPE_DECL node whose TREE_TYPE
         will be the tagged type we just added to the current
         binding level.  This fake NULL-named TYPE_DECL node helps
         dwarfout.c to know when it needs to output a
         representation of a tagged type, and it also gives us a
         convenient place to record the "scope start" address for
         the tagged type.  */

      tree d = build_decl (TYPE_DECL, NULL_TREE, type);
      TYPE_STUB_DECL (type) = pushdecl_with_scope (d, b);
    }
}

/* Counter used to create anonymous type names.  */

static int anon_cnt = 0;

/* Return an IDENTIFIER which can be used as a name for
   anonymous structs and unions.  */

tree
make_anon_name ()
{
  char buf[32];

  sprintf (buf, ANON_AGGRNAME_FORMAT, anon_cnt++);
  return get_identifier (buf);
}

/* Clear the TREE_PURPOSE slot of tags which have anonymous typenames.
   This keeps dbxout from getting confused.  */

void
clear_anon_tags ()
{
  register struct binding_level *b;
  register tree tags;
  static int last_cnt = 0;

  /* Fast out if no new anon names were declared.  */
  if (last_cnt == anon_cnt)
    return;

  b = current_binding_level;
  while (b->tag_transparent)
    b = b->level_chain;
  tags = b->tags;
  while (tags)
    {
      /* A NULL purpose means we have already processed all tags
         from here to the end of the list.  */
      if (TREE_PURPOSE (tags) == NULL_TREE)
        break;
      if (ANON_AGGRNAME_P (TREE_PURPOSE (tags)))
        TREE_PURPOSE (tags) = NULL_TREE;
      tags = TREE_CHAIN (tags);
    }
  last_cnt = anon_cnt;
}
\f
/* Subroutine of duplicate_decls: return truthvalue of whether
   or not types of these decls match.

   For C++, we must compare the parameter list so that `int' can match
   `int&' in a parameter position, but `int&' is not confused with
   `const int&'.  */

int
decls_match (newdecl, olddecl)
     tree newdecl, olddecl;
{
  int types_match;

  if (newdecl == olddecl)
    return 1;

  if (TREE_CODE (newdecl) != TREE_CODE (olddecl))
    /* If the two DECLs are not even the same kind of thing, we're not
       interested in their types.  */
    return 0;

  if (TREE_CODE (newdecl) == FUNCTION_DECL)
    {
      tree f1 = TREE_TYPE (newdecl);
      tree f2 = TREE_TYPE (olddecl);
      tree p1 = TYPE_ARG_TYPES (f1);
      tree p2 = TYPE_ARG_TYPES (f2);

      if (DECL_REAL_CONTEXT (newdecl) != DECL_REAL_CONTEXT (olddecl)
          && ! (DECL_LANGUAGE (newdecl) == lang_c
                && DECL_LANGUAGE (olddecl) == lang_c))
        return 0;

      /* When we parse a static member function definition,
         we put together a FUNCTION_DECL which thinks its type
         is METHOD_TYPE.  Change that to FUNCTION_TYPE, and
         proceed.  */
      if (TREE_CODE (f1) == METHOD_TYPE && DECL_STATIC_FUNCTION_P (olddecl))
        revert_static_member_fn (&newdecl, &f1, &p1);
      else if (TREE_CODE (f2) == METHOD_TYPE
               && DECL_STATIC_FUNCTION_P (newdecl))
        revert_static_member_fn (&olddecl, &f2, &p2);

      /* Here we must take care of the case where new default
         parameters are specified.  Also, warn if an old
         declaration becomes ambiguous because default
         parameters may cause the two to be ambiguous.  */
      if (TREE_CODE (f1) != TREE_CODE (f2))
        {
          if (TREE_CODE (f1) == OFFSET_TYPE)
            cp_compiler_error ("`%D' redeclared as member function", newdecl);
          else
            cp_compiler_error ("`%D' redeclared as non-member function", newdecl);
          return 0;
        }

      if (same_type_p (TREE_TYPE (f1), TREE_TYPE (f2)))
        {
          if (! strict_prototypes_lang_c && DECL_LANGUAGE (olddecl) == lang_c
              && p2 == NULL_TREE)
            {
              types_match = self_promoting_args_p (p1);
              if (p1 == void_list_node)
                TREE_TYPE (newdecl) = TREE_TYPE (olddecl);
            }
          else if (!strict_prototypes_lang_c && DECL_LANGUAGE (olddecl)==lang_c
                   && DECL_LANGUAGE (newdecl) == lang_c && p1 == NULL_TREE)
            {
              types_match = self_promoting_args_p (p2);
              TREE_TYPE (newdecl) = TREE_TYPE (olddecl);
            }
          else
            types_match = compparms (p1, p2);
        }
      else
        types_match = 0;
    }
  else if (TREE_CODE (newdecl) == TEMPLATE_DECL)
    {
      if (!comp_template_parms (DECL_TEMPLATE_PARMS (newdecl),
                                DECL_TEMPLATE_PARMS (olddecl)))
        return 0;
      
      if (TREE_CODE (DECL_TEMPLATE_RESULT (newdecl)) == TYPE_DECL)
        types_match = 1;
      else
        types_match = decls_match (DECL_TEMPLATE_RESULT (olddecl),
                                   DECL_TEMPLATE_RESULT (newdecl));
    }
  else
    {
      if (TREE_TYPE (newdecl) == error_mark_node)
        types_match = TREE_TYPE (olddecl) == error_mark_node;
      else if (TREE_TYPE (olddecl) == NULL_TREE)
        types_match = TREE_TYPE (newdecl) == NULL_TREE;
      else if (TREE_TYPE (newdecl) == NULL_TREE)
        types_match = 0;
      else
        types_match = comptypes (TREE_TYPE (newdecl),
                                 TREE_TYPE (olddecl),
                                 COMPARE_REDECLARATION);
    }

  return types_match;
}

/* If NEWDECL is `static' and an `extern' was seen previously,
   warn about it.  OLDDECL is the previous declaration.

   Note that this does not apply to the C++ case of declaring
   a variable `extern const' and then later `const'.

   Don't complain about built-in functions, since they are beyond
   the user's control.  */

static void
warn_extern_redeclared_static (newdecl, olddecl)
     tree newdecl, olddecl;
{
  static const char *explicit_extern_static_warning
    = "`%D' was declared `extern' and later `static'";
  static const char *implicit_extern_static_warning
    = "`%D' was declared implicitly `extern' and later `static'";

  tree name;

  if (TREE_CODE (newdecl) == TYPE_DECL)
    return;
  
  /* Don't get confused by static member functions; that's a different
     use of `static'.  */
  if (TREE_CODE (newdecl) == FUNCTION_DECL
      && DECL_STATIC_FUNCTION_P (newdecl))
    return;

  /* If the old declaration was `static', or the new one isn't, then
     then everything is OK.  */
  if (DECL_THIS_STATIC (olddecl) || !DECL_THIS_STATIC (newdecl))
    return;

  /* It's OK to declare a builtin function as `static'.  */
  if (TREE_CODE (olddecl) == FUNCTION_DECL
      && DECL_ARTIFICIAL (olddecl))
    return;

  name = DECL_ASSEMBLER_NAME (newdecl);
  cp_pedwarn (IDENTIFIER_IMPLICIT_DECL (name)
              ? implicit_extern_static_warning
              : explicit_extern_static_warning, newdecl);
  cp_pedwarn_at ("previous declaration of `%D'", olddecl);
}

/* Handle when a new declaration NEWDECL has the same name as an old
   one OLDDECL in the same binding contour.  Prints an error message
   if appropriate.

   If safely possible, alter OLDDECL to look like NEWDECL, and return 1.
   Otherwise, return 0.  */

int
duplicate_decls (newdecl, olddecl)
     tree newdecl, olddecl;
{
  unsigned olddecl_uid = DECL_UID (olddecl);
  int olddecl_friend = 0, types_match = 0;
  int new_defines_function = 0;

  if (newdecl == olddecl)
    return 1;

  types_match = decls_match (newdecl, olddecl);

  /* If either the type of the new decl or the type of the old decl is an
     error_mark_node, then that implies that we have already issued an
     error (earlier) for some bogus type specification, and in that case,
     it is rather pointless to harass the user with yet more error message
     about the same declaration, so just pretend the types match here.  */
  if (TREE_TYPE (newdecl) == error_mark_node
      || TREE_TYPE (olddecl) == error_mark_node)
    types_match = 1;
 
  /* Check for redeclaration and other discrepancies. */
  if (TREE_CODE (olddecl) == FUNCTION_DECL
      && DECL_ARTIFICIAL (olddecl))
    {
      if (TREE_CODE (newdecl) != FUNCTION_DECL)
        {
          /* If you declare a built-in or predefined function name as static,
             the old definition is overridden, but optionally warn this was a
             bad choice of name.  */
          if (! TREE_PUBLIC (newdecl))
            {
              if (warn_shadow)
                cp_warning ("shadowing %s function `%#D'",
                            DECL_BUILT_IN (olddecl) ? "built-in" : "library",
                            olddecl);
              /* Discard the old built-in function.  */
              return 0;
            }
          /* If the built-in is not ansi, then programs can override
             it even globally without an error.  */
          else if (! DECL_BUILT_IN (olddecl))
            cp_warning ("library function `%#D' redeclared as non-function `%#D'",
                        olddecl, newdecl);
          else
            {
              cp_error ("declaration of `%#D'", newdecl);
              cp_error ("conflicts with built-in declaration `%#D'",
                        olddecl);
            }
          return 0;
        }
      else if (!types_match)
        {
          if ((DECL_LANGUAGE (newdecl) == lang_c
               && DECL_LANGUAGE (olddecl) == lang_c)
              || compparms (TYPE_ARG_TYPES (TREE_TYPE (newdecl)),
                            TYPE_ARG_TYPES (TREE_TYPE (olddecl))))
            {
              /* A near match; override the builtin.  */

              if (TREE_PUBLIC (newdecl))
                {
                  cp_warning ("new declaration `%#D'", newdecl);
                  cp_warning ("ambiguates built-in declaration `%#D'",
                              olddecl);
                }
              else if (warn_shadow)
                cp_warning ("shadowing %s function `%#D'",
                            DECL_BUILT_IN (olddecl) ? "built-in" : "library",
                            olddecl);
            }
          else
            /* Discard the old built-in function.  */
            return 0;
        }
      
      if (DECL_THIS_STATIC (newdecl) && !DECL_THIS_STATIC (olddecl))
        {
          /* If a builtin function is redeclared as `static', merge
             the declarations, but make the original one static.  */
          DECL_THIS_STATIC (olddecl) = 1;
          TREE_PUBLIC (olddecl) = 0;

          /* Make the olddeclaration consistent with the new one so that
             all remnants of the builtin-ness of this function will be
             banished.  */
          DECL_LANGUAGE (olddecl) = DECL_LANGUAGE (newdecl);
          DECL_RTL (olddecl) = DECL_RTL (newdecl);
          DECL_ASSEMBLER_NAME (olddecl) = DECL_ASSEMBLER_NAME (newdecl);
          SET_IDENTIFIER_GLOBAL_VALUE (DECL_ASSEMBLER_NAME (newdecl),
                                       newdecl);
        }
    }
  else if (TREE_CODE (olddecl) != TREE_CODE (newdecl))
    {
      if ((TREE_CODE (olddecl) == TYPE_DECL && DECL_ARTIFICIAL (olddecl)
           && TREE_CODE (newdecl) != TYPE_DECL
           && ! (TREE_CODE (newdecl) == TEMPLATE_DECL
                 && TREE_CODE (DECL_TEMPLATE_RESULT (newdecl)) == TYPE_DECL))
          || (TREE_CODE (newdecl) == TYPE_DECL && DECL_ARTIFICIAL (newdecl)
              && TREE_CODE (olddecl) != TYPE_DECL
              && ! (TREE_CODE (olddecl) == TEMPLATE_DECL
                    && (TREE_CODE (DECL_TEMPLATE_RESULT (olddecl))
                        == TYPE_DECL))))
        {
          /* We do nothing special here, because C++ does such nasty
             things with TYPE_DECLs.  Instead, just let the TYPE_DECL
             get shadowed, and know that if we need to find a TYPE_DECL
             for a given name, we can look in the IDENTIFIER_TYPE_VALUE
             slot of the identifier.  */
          return 0;
        }

      if ((TREE_CODE (newdecl) == FUNCTION_DECL
           && DECL_FUNCTION_TEMPLATE_P (olddecl))
          || (TREE_CODE (olddecl) == FUNCTION_DECL
              && DECL_FUNCTION_TEMPLATE_P (newdecl)))
        return 0;

      cp_error ("`%#D' redeclared as different kind of symbol", newdecl);
      if (TREE_CODE (olddecl) == TREE_LIST)
        olddecl = TREE_VALUE (olddecl);
      cp_error_at ("previous declaration of `%#D'", olddecl);

      /* New decl is completely inconsistent with the old one =>
         tell caller to replace the old one.  */

      return 0;
    }
  else if (!types_match)
    {
      if (DECL_REAL_CONTEXT (newdecl) != DECL_REAL_CONTEXT (olddecl))
        /* These are certainly not duplicate declarations; they're
           from different scopes.  */
        return 0;

      if (TREE_CODE (newdecl) == TEMPLATE_DECL)
        {
          /* The name of a class template may not be declared to refer to
             any other template, class, function, object, namespace, value,
             or type in the same scope.  */
          if (TREE_CODE (DECL_TEMPLATE_RESULT (olddecl)) == TYPE_DECL
              || TREE_CODE (DECL_TEMPLATE_RESULT (newdecl)) == TYPE_DECL)
            {
              cp_error ("declaration of template `%#D'", newdecl);
              cp_error_at ("conflicts with previous declaration `%#D'",
                           olddecl);
            }
          else if (TREE_CODE (DECL_TEMPLATE_RESULT (olddecl)) == FUNCTION_DECL
                   && TREE_CODE (DECL_TEMPLATE_RESULT (newdecl)) == FUNCTION_DECL
                   && compparms (TYPE_ARG_TYPES (TREE_TYPE (DECL_TEMPLATE_RESULT (olddecl))),
                                 TYPE_ARG_TYPES (TREE_TYPE (DECL_TEMPLATE_RESULT (newdecl))))
                   && comp_template_parms (DECL_TEMPLATE_PARMS (newdecl),
                                           DECL_TEMPLATE_PARMS (olddecl)))
            {
              cp_error ("new declaration `%#D'", newdecl);
              cp_error_at ("ambiguates old declaration `%#D'", olddecl);
            }
          return 0;
        }
      if (TREE_CODE (newdecl) == FUNCTION_DECL)
        {
          if (DECL_LANGUAGE (newdecl) == lang_c
              && DECL_LANGUAGE (olddecl) == lang_c)
            {
              cp_error ("declaration of C function `%#D' conflicts with",
                        newdecl);
              cp_error_at ("previous declaration `%#D' here", olddecl);
            }
          else if (compparms (TYPE_ARG_TYPES (TREE_TYPE (newdecl)),
                              TYPE_ARG_TYPES (TREE_TYPE (olddecl))))
            {
              cp_error ("new declaration `%#D'", newdecl);
              cp_error_at ("ambiguates old declaration `%#D'", olddecl);
            }
          else
            return 0;
        }

      /* Already complained about this, so don't do so again.  */
      else if (current_class_type == NULL_TREE
          || IDENTIFIER_ERROR_LOCUS (DECL_ASSEMBLER_NAME (newdecl)) != current_class_type)
        {
          cp_error ("conflicting types for `%#D'", newdecl);
          cp_error_at ("previous declaration as `%#D'", olddecl);
        }
    }
  else if (TREE_CODE (newdecl) == FUNCTION_DECL 
            && ((DECL_TEMPLATE_SPECIALIZATION (olddecl)
                 && (!DECL_TEMPLATE_INFO (newdecl)
                     || (DECL_TI_TEMPLATE (newdecl) 
                         != DECL_TI_TEMPLATE (olddecl))))
                || (DECL_TEMPLATE_SPECIALIZATION (newdecl)
                    && (!DECL_TEMPLATE_INFO (olddecl)
                        || (DECL_TI_TEMPLATE (olddecl) 
                            != DECL_TI_TEMPLATE (newdecl))))))
    /* It's OK to have a template specialization and a non-template
       with the same type, or to have specializations of two
       different templates with the same type.  Note that if one is a
       specialization, and the other is an instantiation of the same
       template, that we do not exit at this point.  That situation
       can occur if we instantiate a template class, and then
       specialize one of its methods.  This situation is legal, but
       the declarations must be merged in the usual way.  */
    return 0;
  else if (TREE_CODE (newdecl) == FUNCTION_DECL 
           && ((DECL_TEMPLATE_INSTANTIATION (olddecl) 
                && !DECL_USE_TEMPLATE (newdecl))
               || (DECL_TEMPLATE_INSTANTIATION (newdecl)
                   && !DECL_USE_TEMPLATE (olddecl))))
    /* One of the declarations is a template instantiation, and the
       other is not a template at all.  That's OK.  */
    return 0;
  else if (TREE_CODE (newdecl) == NAMESPACE_DECL
           && DECL_NAMESPACE_ALIAS (newdecl)
           && DECL_NAMESPACE_ALIAS (newdecl) == DECL_NAMESPACE_ALIAS (olddecl))
    /* Redeclaration of namespace alias, ignore it. */
    return 1;
  else
    {
      const char *errmsg = redeclaration_error_message (newdecl, olddecl);
      if (errmsg)
        {
          cp_error (errmsg, newdecl);
          if (DECL_NAME (olddecl) != NULL_TREE)
            cp_error_at ((DECL_INITIAL (olddecl)
                          && namespace_bindings_p ())
                         ? "`%#D' previously defined here"
                         : "`%#D' previously declared here", olddecl);
        }
      else if (TREE_CODE (olddecl) == FUNCTION_DECL
               && DECL_INITIAL (olddecl) != NULL_TREE
               && TYPE_ARG_TYPES (TREE_TYPE (olddecl)) == NULL_TREE
               && TYPE_ARG_TYPES (TREE_TYPE (newdecl)) != NULL_TREE)
        {
          /* Prototype decl follows defn w/o prototype.  */
          cp_warning_at ("prototype for `%#D'", newdecl);
          cp_warning_at ("follows non-prototype definition here", olddecl);
        }
      else if (TREE_CODE (olddecl) == FUNCTION_DECL
               && DECL_LANGUAGE (newdecl) != DECL_LANGUAGE (olddecl))
        {
          /* extern "C" int foo ();
             int foo () { bar (); }
             is OK.  */
          if (current_lang_stack
              == &VARRAY_TREE (current_lang_base, 0))
            DECL_LANGUAGE (newdecl) = DECL_LANGUAGE (olddecl);
          else
            {
              cp_error_at ("previous declaration of `%#D' with %L linkage",
                           olddecl, DECL_LANGUAGE (olddecl));
              cp_error ("conflicts with new declaration with %L linkage",
                        DECL_LANGUAGE (newdecl));
            }
        }

      if (DECL_LANG_SPECIFIC (olddecl) && DECL_USE_TEMPLATE (olddecl))
        ;
      else if (TREE_CODE (olddecl) == FUNCTION_DECL)
        {
          tree t1 = TYPE_ARG_TYPES (TREE_TYPE (olddecl));
          tree t2 = TYPE_ARG_TYPES (TREE_TYPE (newdecl));
          int i = 1;

          if (TREE_CODE (TREE_TYPE (newdecl)) == METHOD_TYPE)
            t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2);
        
          for (; t1 && t1 != void_list_node;
               t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2), i++)
            if (TREE_PURPOSE (t1) && TREE_PURPOSE (t2))
              {
                if (1 == simple_cst_equal (TREE_PURPOSE (t1),
                                           TREE_PURPOSE (t2)))
                  {
                    if (pedantic)
                      {
                        cp_pedwarn ("default argument given for parameter %d of `%#D'",
                                    i, newdecl);
                        cp_pedwarn_at ("after previous specification in `%#D'",
                                       olddecl);
                      }
                  }
                else
                  {
                    cp_error ("default argument given for parameter %d of `%#D'",
                              i, newdecl);
                    cp_error_at ("after previous specification in `%#D'",
                                 olddecl);
                  }
              }

          if (DECL_THIS_INLINE (newdecl) && ! DECL_THIS_INLINE (olddecl)
              && TREE_ADDRESSABLE (olddecl) && warn_inline)
            {
              cp_warning ("`%#D' was used before it was declared inline",
                          newdecl);
              cp_warning_at ("previous non-inline declaration here",
                             olddecl);
            }
        }
    }

  /* If new decl is `static' and an `extern' was seen previously,
     warn about it.  */
  warn_extern_redeclared_static (newdecl, olddecl);

  /* We have committed to returning 1 at this point.  */
  if (TREE_CODE (newdecl) == FUNCTION_DECL)
    {
      /* Now that functions must hold information normally held
         by field decls, there is extra work to do so that
         declaration information does not get destroyed during
         definition.  */
      if (DECL_VINDEX (olddecl))
        DECL_VINDEX (newdecl) = DECL_VINDEX (olddecl);
      if (DECL_CONTEXT (olddecl))
        DECL_CONTEXT (newdecl) = DECL_CONTEXT (olddecl);
      if (DECL_CLASS_CONTEXT (olddecl))
        DECL_CLASS_CONTEXT (newdecl) = DECL_CLASS_CONTEXT (olddecl);
      if (DECL_PENDING_INLINE_INFO (newdecl) == (struct pending_inline *)0)
        DECL_PENDING_INLINE_INFO (newdecl) = DECL_PENDING_INLINE_INFO (olddecl);
      DECL_STATIC_CONSTRUCTOR (newdecl) |= DECL_STATIC_CONSTRUCTOR (olddecl);
      DECL_STATIC_DESTRUCTOR (newdecl) |= DECL_STATIC_DESTRUCTOR (olddecl);
      DECL_ABSTRACT_VIRTUAL_P (newdecl) |= DECL_ABSTRACT_VIRTUAL_P (olddecl);
      DECL_VIRTUAL_P (newdecl) |= DECL_VIRTUAL_P (olddecl);
      DECL_NEEDS_FINAL_OVERRIDER_P (newdecl) |= DECL_NEEDS_FINAL_OVERRIDER_P (olddecl);
      DECL_THIS_STATIC (newdecl) |= DECL_THIS_STATIC (olddecl);
      new_defines_function = DECL_INITIAL (newdecl) != NULL_TREE;
      
      /* Optionally warn about more than one declaration for the same
         name, but don't warn about a function declaration followed by a
         definition.  */
      if (warn_redundant_decls && ! DECL_ARTIFICIAL (olddecl)
          && !(new_defines_function && DECL_INITIAL (olddecl) == NULL_TREE)
          /* Don't warn about extern decl followed by definition. */
          && !(DECL_EXTERNAL (olddecl) && ! DECL_EXTERNAL (newdecl))
          /* Don't warn about friends, let add_friend take care of it. */
          && ! DECL_FRIEND_P (newdecl))
        {
          cp_warning ("redundant redeclaration of `%D' in same scope", newdecl);
          cp_warning_at ("previous declaration of `%D'", olddecl);
        }
    }

  /* Deal with C++: must preserve virtual function table size.  */
  if (TREE_CODE (olddecl) == TYPE_DECL)
    {
      register tree newtype = TREE_TYPE (newdecl);
      register tree oldtype = TREE_TYPE (olddecl);

      if (newtype != error_mark_node && oldtype != error_mark_node
          && TYPE_LANG_SPECIFIC (newtype) && TYPE_LANG_SPECIFIC (oldtype))
        {
          CLASSTYPE_VSIZE (newtype) = CLASSTYPE_VSIZE (oldtype);
          CLASSTYPE_FRIEND_CLASSES (newtype)
            = CLASSTYPE_FRIEND_CLASSES (oldtype);
        }
    }

  /* Copy all the DECL_... slots specified in the new decl
     except for any that we copy here from the old type.  */
  DECL_MACHINE_ATTRIBUTES (newdecl) 
    = merge_machine_decl_attributes (olddecl, newdecl);

  if (TREE_CODE (newdecl) == TEMPLATE_DECL)
    {
      if (! duplicate_decls (DECL_TEMPLATE_RESULT (newdecl),
                             DECL_TEMPLATE_RESULT (olddecl)))
        cp_error ("invalid redeclaration of %D", newdecl);
      TREE_TYPE (olddecl) = TREE_TYPE (DECL_TEMPLATE_RESULT (olddecl));
      DECL_TEMPLATE_SPECIALIZATIONS (olddecl) 
        = chainon (DECL_TEMPLATE_SPECIALIZATIONS (olddecl),
                   DECL_TEMPLATE_SPECIALIZATIONS (newdecl));
 
      return 1;
    }
    
  if (types_match)
    {
      /* Automatically handles default parameters.  */
      tree oldtype = TREE_TYPE (olddecl);
      tree newtype;

      /* Make sure we put the new type in the same obstack as the old one.  */
      if (oldtype)
        push_obstacks (TYPE_OBSTACK (oldtype), TYPE_OBSTACK (oldtype));
      else
        push_permanent_obstack ();

      /* Merge the data types specified in the two decls.  */
      newtype = common_type (TREE_TYPE (newdecl), TREE_TYPE (olddecl));

      if (TREE_CODE (newdecl) == VAR_DECL)
        DECL_THIS_EXTERN (newdecl) |= DECL_THIS_EXTERN (olddecl);
      /* Do this after calling `common_type' so that default
         parameters don't confuse us.  */
      else if (TREE_CODE (newdecl) == FUNCTION_DECL
          && (TYPE_RAISES_EXCEPTIONS (TREE_TYPE (newdecl))
              != TYPE_RAISES_EXCEPTIONS (TREE_TYPE (olddecl))))
        {
          TREE_TYPE (newdecl) = build_exception_variant (newtype,
                                                         TYPE_RAISES_EXCEPTIONS (TREE_TYPE (newdecl)));
          TREE_TYPE (olddecl) = build_exception_variant (newtype,
                                                         TYPE_RAISES_EXCEPTIONS (oldtype));

          if ((pedantic || ! DECL_IN_SYSTEM_HEADER (olddecl))
              && DECL_SOURCE_LINE (olddecl) != 0
              && flag_exceptions
              && !comp_except_specs (TYPE_RAISES_EXCEPTIONS (TREE_TYPE (newdecl)),
                                     TYPE_RAISES_EXCEPTIONS (TREE_TYPE (olddecl)), 1))
            {
              cp_error ("declaration of `%F' throws different exceptions",
                        newdecl);
              cp_error_at ("to previous declaration `%F'", olddecl);
            }
        }
      TREE_TYPE (newdecl) = TREE_TYPE (olddecl) = newtype;

      /* Lay the type out, unless already done.  */
      if (! same_type_p (newtype, oldtype)
          && TREE_TYPE (newdecl) != error_mark_node
          && !(processing_template_decl && uses_template_parms (newdecl)))
        layout_type (TREE_TYPE (newdecl));

      if ((TREE_CODE (newdecl) == VAR_DECL
           || TREE_CODE (newdecl) == PARM_DECL
           || TREE_CODE (newdecl) == RESULT_DECL
           || TREE_CODE (newdecl) == FIELD_DECL
           || TREE_CODE (newdecl) == TYPE_DECL)
          && !(processing_template_decl && uses_template_parms (newdecl)))
        layout_decl (newdecl, 0);

      /* Merge the type qualifiers.  */
      if (TREE_READONLY (newdecl))
        TREE_READONLY (olddecl) = 1;
      if (TREE_THIS_VOLATILE (newdecl))
        TREE_THIS_VOLATILE (olddecl) = 1;

      /* Merge the initialization information.  */
      if (DECL_INITIAL (newdecl) == NULL_TREE
          && DECL_INITIAL (olddecl) != NULL_TREE)
        {
          DECL_INITIAL (newdecl) = DECL_INITIAL (olddecl);
          DECL_SOURCE_FILE (newdecl) = DECL_SOURCE_FILE (olddecl);
          DECL_SOURCE_LINE (newdecl) = DECL_SOURCE_LINE (olddecl);
          if (CAN_HAVE_FULL_LANG_DECL_P (newdecl)
              && DECL_LANG_SPECIFIC (newdecl)
              && DECL_LANG_SPECIFIC (olddecl))
            DECL_SAVED_TREE (newdecl) = DECL_SAVED_TREE (olddecl);
        }

      /* Merge the section attribute.
         We want to issue an error if the sections conflict but that must be
         done later in decl_attributes since we are called before attributes
         are assigned.  */
      if (DECL_SECTION_NAME (newdecl) == NULL_TREE)
        DECL_SECTION_NAME (newdecl) = DECL_SECTION_NAME (olddecl);

      /* Keep the old rtl since we can safely use it.  */
      DECL_RTL (newdecl) = DECL_RTL (olddecl);

      pop_obstacks ();
    }
  /* If cannot merge, then use the new type and qualifiers,
     and don't preserve the old rtl.  */
  else
    {
      /* Clean out any memory we had of the old declaration.  */
      tree oldstatic = value_member (olddecl, static_aggregates);
      if (oldstatic)
        TREE_VALUE (oldstatic) = error_mark_node;

      TREE_TYPE (olddecl) = TREE_TYPE (newdecl);
      TREE_READONLY (olddecl) = TREE_READONLY (newdecl);
      TREE_THIS_VOLATILE (olddecl) = TREE_THIS_VOLATILE (newdecl);
      TREE_SIDE_EFFECTS (olddecl) = TREE_SIDE_EFFECTS (newdecl);
    }

  /* Merge the storage class information.  */
  DECL_WEAK (newdecl) |= DECL_WEAK (olddecl);
  DECL_ONE_ONLY (newdecl) |= DECL_ONE_ONLY (olddecl);
  TREE_PUBLIC (newdecl) = TREE_PUBLIC (olddecl);
  TREE_STATIC (olddecl) = TREE_STATIC (newdecl) |= TREE_STATIC (olddecl);
  if (! DECL_EXTERNAL (olddecl))
    DECL_EXTERNAL (newdecl) = 0;
  
  if (DECL_LANG_SPECIFIC (newdecl) && DECL_LANG_SPECIFIC (olddecl))
    {
      DECL_INTERFACE_KNOWN (newdecl) |= DECL_INTERFACE_KNOWN (olddecl);
      DECL_NOT_REALLY_EXTERN (newdecl) |= DECL_NOT_REALLY_EXTERN (olddecl);
      DECL_COMDAT (newdecl) |= DECL_COMDAT (olddecl);
      DECL_TEMPLATE_INSTANTIATED (newdecl) 
        |= DECL_TEMPLATE_INSTANTIATED (olddecl);
      /* Don't really know how much of the language-specific
         values we should copy from old to new.  */
      DECL_IN_AGGR_P (newdecl) = DECL_IN_AGGR_P (olddecl);
      DECL_ACCESS (newdecl) = DECL_ACCESS (olddecl);
      DECL_NONCONVERTING_P (newdecl) = DECL_NONCONVERTING_P (olddecl);
      DECL_TEMPLATE_INFO (newdecl) = DECL_TEMPLATE_INFO (olddecl);
      olddecl_friend = DECL_FRIEND_P (olddecl);

      /* Only functions have DECL_BEFRIENDING_CLASSES.  */
      if (TREE_CODE (newdecl) == FUNCTION_DECL
          || DECL_FUNCTION_TEMPLATE_P (newdecl))
        DECL_BEFRIENDING_CLASSES (newdecl)
          = chainon (DECL_BEFRIENDING_CLASSES (newdecl),
                     DECL_BEFRIENDING_CLASSES (olddecl));
    }

  if (TREE_CODE (newdecl) == FUNCTION_DECL)
    {
      if (DECL_TEMPLATE_INSTANTIATION (olddecl) 
          && !DECL_TEMPLATE_INSTANTIATION (newdecl)) 
        {
          /* If newdecl is not a specialization, then it is not a
             template-related function at all.  And that means that we
             shoud have exited above, returning 0.  */
          my_friendly_assert (DECL_TEMPLATE_SPECIALIZATION (newdecl),
                              0);

          if (TREE_USED (olddecl)) 
            /* From [temp.expl.spec]:
               
               If a template, a member template or the member of a class
               template is explicitly specialized then that
               specialization shall be declared before the first use of
               that specialization that would cause an implicit
               instantiation to take place, in every translation unit in
               which such a use occurs.  */
            cp_error ("explicit specialization of %D after first use", 
                      olddecl);

          SET_DECL_TEMPLATE_SPECIALIZATION (olddecl);
        }
      DECL_THIS_INLINE (newdecl) |= DECL_THIS_INLINE (olddecl);

      /* If either decl says `inline', this fn is inline, unless its
         definition was passed already.  */
      if (DECL_INLINE (newdecl) && DECL_INITIAL (olddecl) == NULL_TREE)
        DECL_INLINE (olddecl) = 1;
      DECL_INLINE (newdecl) = DECL_INLINE (olddecl);

      if (! types_match)
        {
          DECL_LANGUAGE (olddecl) = DECL_LANGUAGE (newdecl);
          DECL_ASSEMBLER_NAME (olddecl) = DECL_ASSEMBLER_NAME (newdecl);
          DECL_RTL (olddecl) = DECL_RTL (newdecl);
        }
      if (! types_match || new_defines_function)
        {
          /* These need to be copied so that the names are available.
             Note that if the types do match, we'll preserve inline
             info and other bits, but if not, we won't.  */
          DECL_ARGUMENTS (olddecl) = DECL_ARGUMENTS (newdecl);
          DECL_RESULT (olddecl) = DECL_RESULT (newdecl);
        }
      if (new_defines_function)
        /* If defining a function declared with other language
           linkage, use the previously declared language linkage.  */
        DECL_LANGUAGE (newdecl) = DECL_LANGUAGE (olddecl);
      else if (types_match)
        {
          /* If redeclaring a builtin function, and not a definition,
             it stays built in.  */
          if (DECL_BUILT_IN (olddecl))
            {
              DECL_BUILT_IN_CLASS (newdecl) = DECL_BUILT_IN_CLASS (olddecl);
              DECL_FUNCTION_CODE (newdecl) = DECL_FUNCTION_CODE (olddecl);
              /* If we're keeping the built-in definition, keep the rtl,
                 regardless of declaration matches.  */
              DECL_RTL (newdecl) = DECL_RTL (olddecl);
            }
          else
            DECL_FRAME_SIZE (newdecl) = DECL_FRAME_SIZE (olddecl);

          DECL_RESULT (newdecl) = DECL_RESULT (olddecl);
          if ((DECL_SAVED_INSNS (newdecl) = DECL_SAVED_INSNS (olddecl)))
            /* Previously saved insns go together with
               the function's previous definition.  */
            DECL_INITIAL (newdecl) = DECL_INITIAL (olddecl);
          /* Don't clear out the arguments if we're redefining a function.  */
          if (DECL_ARGUMENTS (olddecl))
            DECL_ARGUMENTS (newdecl) = DECL_ARGUMENTS (olddecl);
        }
      if (DECL_LANG_SPECIFIC (olddecl))
        DECL_MAIN_VARIANT (newdecl) = DECL_MAIN_VARIANT (olddecl);
    }

  if (TREE_CODE (newdecl) == NAMESPACE_DECL)
    {
      NAMESPACE_LEVEL (newdecl) = NAMESPACE_LEVEL (olddecl);
    }

  /* Now preserve various other info from the definition.  */
  TREE_ADDRESSABLE (newdecl) = TREE_ADDRESSABLE (olddecl);
  TREE_ASM_WRITTEN (newdecl) = TREE_ASM_WRITTEN (olddecl);
  DECL_COMMON (newdecl) = DECL_COMMON (olddecl);
  DECL_ASSEMBLER_NAME (newdecl) = DECL_ASSEMBLER_NAME (olddecl);

  if (TREE_CODE (newdecl) == FUNCTION_DECL)
    {
      int function_size;

      function_size = sizeof (struct tree_decl);

      bcopy ((char *) newdecl + sizeof (struct tree_common),
             (char *) olddecl + sizeof (struct tree_common),
             function_size - sizeof (struct tree_common));

      if (DECL_TEMPLATE_INSTANTIATION (newdecl))
        {
          /* If newdecl is a template instantiation, it is possible that
             the following sequence of events has occurred:

             o A friend function was declared in a class template.  The
             class template was instantiated.  

             o The instantiation of the friend declaration was 
             recorded on the instantiation list, and is newdecl.  

             o Later, however, instantiate_class_template called pushdecl
             on the newdecl to perform name injection.  But, pushdecl in
             turn called duplicate_decls when it discovered that another
             declaration of a global function with the same name already
             existed. 

             o Here, in duplicate_decls, we decided to clobber newdecl.

             If we're going to do that, we'd better make sure that
             olddecl, and not newdecl, is on the list of
             instantiations so that if we try to do the instantiation
             again we won't get the clobbered declaration.  */

          tree tmpl = DECL_TI_TEMPLATE (newdecl); 
          tree decls = DECL_TEMPLATE_SPECIALIZATIONS (tmpl); 

          for (; decls; decls = TREE_CHAIN (decls))
            if (TREE_VALUE (decls) == newdecl)
              TREE_VALUE (decls) = olddecl;
        }
    }
  else
    {
      bcopy ((char *) newdecl + sizeof (struct tree_common),
             (char *) olddecl + sizeof (struct tree_common),
             sizeof (struct tree_decl) - sizeof (struct tree_common)
             + tree_code_length [(int)TREE_CODE (newdecl)] * sizeof (char *));
    }

  DECL_UID (olddecl) = olddecl_uid;
  if (olddecl_friend)
    DECL_FRIEND_P (olddecl) = 1;

  /* NEWDECL contains the merged attribute lists.
     Update OLDDECL to be the same.  */
  DECL_MACHINE_ATTRIBUTES (olddecl) = DECL_MACHINE_ATTRIBUTES (newdecl);

  return 1;
}

/* Record a decl-node X as belonging to the current lexical scope.
   Check for errors (such as an incompatible declaration for the same
   name already seen in the same scope).

   Returns either X or an old decl for the same name.
   If an old decl is returned, it may have been smashed
   to agree with what X says.  */

tree
pushdecl (x)
     tree x;
{
  register tree t;
  register tree name;
  int need_new_binding;

  /* We shouldn't be calling pushdecl when we're generating RTL for a
     function that we already did semantic analysis on previously.  */
  my_friendly_assert (!current_function || doing_semantic_analysis_p (),
                      19990913);

  name = DECL_ASSEMBLER_NAME (x);
  need_new_binding = 1;

  if (DECL_TEMPLATE_PARM_P (x))
    /* Template parameters have no context; they are not X::T even
       when declared within a class or namespace.  */
    ;
  else
    {
      if (current_function_decl && x != current_function_decl
          /* A local declaration for a function doesn't constitute
             nesting.  */
          && !(TREE_CODE (x) == FUNCTION_DECL && !DECL_INITIAL (x))
          /* A local declaration for an `extern' variable is in the
             scoped of the current namespace, not the current
             function.  */
          && !(TREE_CODE (x) == VAR_DECL && DECL_EXTERNAL (x))
          /* Don't change DECL_CONTEXT of virtual methods.  */
          && (TREE_CODE (x) != FUNCTION_DECL || !DECL_VIRTUAL_P (x))
          && !DECL_CONTEXT (x))
        DECL_CONTEXT (x) = current_function_decl;
      if (!DECL_CONTEXT (x))
        DECL_CONTEXT (x) = FROB_CONTEXT (current_namespace);
    }

  /* Type are looked up using the DECL_NAME, as that is what the rest of the
     compiler wants to use.  */
  if (TREE_CODE (x) == TYPE_DECL || TREE_CODE (x) == VAR_DECL
      || TREE_CODE (x) == NAMESPACE_DECL)
    name = DECL_NAME (x);

  if (name)
    {
#if 0
      /* Not needed...see below.  */
      char *file;
      int line;
#endif
      if (TREE_CODE (name) == TEMPLATE_ID_EXPR)
        name = TREE_OPERAND (name, 0);
      
      /* Namespace-scoped variables are not found in the current level. */
      if (TREE_CODE (x) == VAR_DECL && DECL_NAMESPACE_SCOPE_P (x))
        t = namespace_binding (name, DECL_CONTEXT (x));
      else
        t = lookup_name_current_level (name);
      if (t == error_mark_node)
        {
          /* error_mark_node is 0 for a while during initialization!  */
          t = NULL_TREE;
          cp_error_at ("`%#D' used prior to declaration", x);
        }

      else if (t != NULL_TREE)
        {
#if 0
          /* This is turned off until I have time to do it right (bpk).  */
          /* With the code below that uses it...  */
          file = DECL_SOURCE_FILE (t);
          line = DECL_SOURCE_LINE (t);
#endif
          if (TREE_CODE (t) == PARM_DECL)
            {
              if (DECL_CONTEXT (t) == NULL_TREE)
                fatal ("parse errors have confused me too much");

              /* Check for duplicate params.  */
              if (duplicate_decls (x, t))
                return t;
            }
          else if (((TREE_CODE (x) == FUNCTION_DECL && DECL_LANGUAGE (x) == lang_c)
                    || DECL_FUNCTION_TEMPLATE_P (x))
                   && is_overloaded_fn (t))
            /* Don't do anything just yet. */;
          else if (t == wchar_decl_node)
            {
              if (pedantic && ! DECL_IN_SYSTEM_HEADER (x))
                cp_pedwarn ("redeclaration of wchar_t as `%T'", TREE_TYPE (x));

              /* Throw away the redeclaration.  */
              return t;
            }
          else if (TREE_CODE (t) != TREE_CODE (x))
            {
              if (duplicate_decls (x, t))
                return t;
            }
          else if (duplicate_decls (x, t))
            {
#if 0
              /* This is turned off until I have time to do it right (bpk).  */

              /* Also warn if they did a prototype with `static' on it, but
                 then later left the `static' off.  */
              if (! TREE_PUBLIC (name) && TREE_PUBLIC (x))
                {
                  if (DECL_LANG_SPECIFIC (t) && DECL_FRIEND_P (t))
                    return t;

                  if (extra_warnings)
                    {
                      cp_warning ("`static' missing from declaration of `%D'",
                                  t);
                      warning_with_file_and_line (file, line,
                                                  "previous declaration of `%s'",
                                                  decl_as_string (t, 0));
                    }

                  /* Now fix things so it'll do what they expect.  */
                  if (current_function_decl)
                    TREE_PUBLIC (current_function_decl) = 0;
                }
              /* Due to interference in memory reclamation (X may be
                 obstack-deallocated at this point), we must guard against
                 one really special case.  [jason: This should be handled
                 by start_function]  */
              if (current_function_decl == x)
                current_function_decl = t;
#endif
              if (TREE_CODE (t) == TYPE_DECL)
                SET_IDENTIFIER_TYPE_VALUE (name, TREE_TYPE (t));
              else if (TREE_CODE (t) == FUNCTION_DECL)
                check_default_args (t);

              return t;
            }
          else if (DECL_MAIN_P (x))
            {
              /* A redeclaration of main, but not a duplicate of the
                 previous one. 

                 [basic.start.main]

                 This function shall not be overloaded.  */
              cp_error_at ("invalid redeclaration of `%D'", t);
              cp_error ("as `%D'", x);
              /* We don't try to push this declaration since that
                 causes a crash.  */
              return x;
            }
        }

      check_template_shadow (x);

      /* If this is a function conjured up by the backend, massage it
         so it looks friendly.  */
      if (TREE_CODE (x) == FUNCTION_DECL
          && ! DECL_LANG_SPECIFIC (x))
        {
          retrofit_lang_decl (x);
          DECL_LANGUAGE (x) = lang_c;
        }

      if (TREE_CODE (x) == FUNCTION_DECL && ! DECL_FUNCTION_MEMBER_P (x))
        {
          t = push_overloaded_decl (x, PUSH_LOCAL);
          if (t != x)
            return t;
          if (!namespace_bindings_p ())
            /* We do not need to create a binding for this name;
               push_overloaded_decl will have already done so if
               necessary.  */
            need_new_binding = 0;
        }
      else if (DECL_FUNCTION_TEMPLATE_P (x) && DECL_NAMESPACE_SCOPE_P (x))
        {
          t = push_overloaded_decl (x, PUSH_GLOBAL);
          if (t == x)
            add_decl_to_level (x, NAMESPACE_LEVEL (CP_DECL_CONTEXT (t)));
          return t;
        }

      /* If declaring a type as a typedef, copy the type (unless we're
         at line 0), and install this TYPE_DECL as the new type's typedef
         name.  See the extensive comment in ../c-decl.c (pushdecl). */
      if (TREE_CODE (x) == TYPE_DECL)
        {
          tree type = TREE_TYPE (x);
          if (DECL_SOURCE_LINE (x) == 0)
            {
              if (TYPE_NAME (type) == 0)
                TYPE_NAME (type) = x;
            }
          else if (type != error_mark_node && TYPE_NAME (type) != x
                   /* We don't want to copy the type when all we're
                      doing is making a TYPE_DECL for the purposes of
                      inlining.  */
                   && (!TYPE_NAME (type) 
                       || TYPE_NAME (type) != DECL_ABSTRACT_ORIGIN (x)))
            {
              push_obstacks (TYPE_OBSTACK (type), TYPE_OBSTACK (type));

              DECL_ORIGINAL_TYPE (x) = type;
              type = build_type_copy (type);
              TYPE_STUB_DECL (type) = TYPE_STUB_DECL (DECL_ORIGINAL_TYPE (x));
              TYPE_NAME (type) = x;
              TREE_TYPE (x) = type;

              pop_obstacks ();
            }

          if (type != error_mark_node
              && TYPE_NAME (type)
              && TYPE_IDENTIFIER (type))
            set_identifier_type_value_with_scope (DECL_NAME (x), type, 
                                                  current_binding_level);

        }

      /* Multiple external decls of the same identifier ought to match.

         We get warnings about inline functions where they are defined.
         We get warnings about other functions from push_overloaded_decl.
         
         Avoid duplicate warnings where they are used.  */
      if (TREE_PUBLIC (x) && TREE_CODE (x) != FUNCTION_DECL)
        {
          tree decl;

          if (IDENTIFIER_NAMESPACE_VALUE (name) != NULL_TREE
              && (DECL_EXTERNAL (IDENTIFIER_NAMESPACE_VALUE (name))
                  || TREE_PUBLIC (IDENTIFIER_NAMESPACE_VALUE (name))))
            decl = IDENTIFIER_NAMESPACE_VALUE (name);
          else
            decl = NULL_TREE;

          if (decl
              /* If different sort of thing, we already gave an error.  */
              && TREE_CODE (decl) == TREE_CODE (x)
              && !same_type_p (TREE_TYPE (x), TREE_TYPE (decl)))
            {
              cp_pedwarn ("type mismatch with previous external decl", x);
              cp_pedwarn_at ("previous external decl of `%#D'", decl);
            }
        }

      /* This name is new in its binding level.
         Install the new declaration and return it.  */
      if (namespace_bindings_p ())
        {
          /* Install a global value.  */

          /* If the first global decl has external linkage,
             warn if we later see static one.  */
          if (IDENTIFIER_GLOBAL_VALUE (name) == NULL_TREE && TREE_PUBLIC (x))
            TREE_PUBLIC (name) = 1;

          if (!(TREE_CODE (x) == TYPE_DECL && DECL_ARTIFICIAL (x)
                && t != NULL_TREE)
              /* For an ordinary function, we create a binding from
                 the mangled name (i.e., NAME) to the DECL.  But, for
                 an `extern "C"' function, the mangled name and the
                 ordinary name are the same so we need not do this.  */
              && !(TREE_CODE (x) == FUNCTION_DECL && 
                   DECL_LANGUAGE (x) == lang_c))
            {
              if (TREE_CODE (x) == FUNCTION_DECL)
                my_friendly_assert 
                  ((IDENTIFIER_GLOBAL_VALUE (name) == NULL_TREE)
                  || (IDENTIFIER_GLOBAL_VALUE (name) == x), 378);
              SET_IDENTIFIER_NAMESPACE_VALUE (name, x);
            }

          /* Don't forget if the function was used via an implicit decl.  */
          if (IDENTIFIER_IMPLICIT_DECL (name)
              && TREE_USED (IDENTIFIER_IMPLICIT_DECL (name)))
            TREE_USED (x) = 1;

          /* Don't forget if its address was taken in that way.  */
          if (IDENTIFIER_IMPLICIT_DECL (name)
              && TREE_ADDRESSABLE (IDENTIFIER_IMPLICIT_DECL (name)))
            TREE_ADDRESSABLE (x) = 1;

          /* Warn about mismatches against previous implicit decl.  */
          if (IDENTIFIER_IMPLICIT_DECL (name) != NULL_TREE
              /* If this real decl matches the implicit, don't complain.  */
              && ! (TREE_CODE (x) == FUNCTION_DECL
                    && TREE_TYPE (TREE_TYPE (x)) == integer_type_node))
            cp_warning
              ("`%D' was previously implicitly declared to return `int'", x);

          /* If new decl is `static' and an `extern' was seen previously,
             warn about it.  */
          if (x != NULL_TREE && t != NULL_TREE && decls_match (x, t))
            warn_extern_redeclared_static (x, t);
        }
      else
        {
          /* Here to install a non-global value.  */
          tree oldlocal = IDENTIFIER_VALUE (name);
          tree oldglobal = IDENTIFIER_NAMESPACE_VALUE (name);

          if (need_new_binding)
            {
              push_local_binding (name, x, 0);
              /* Because push_local_binding will hook X on to the
                 current_binding_level's name list, we don't want to
                 do that again below.  */
              need_new_binding = 0;
            }

          /* If this is a TYPE_DECL, push it into the type value slot.  */
          if (TREE_CODE (x) == TYPE_DECL)
            set_identifier_type_value_with_scope (name, TREE_TYPE (x), 
                                                  current_binding_level);

          /* Clear out any TYPE_DECL shadowed by a namespace so that
             we won't think this is a type.  The C struct hack doesn't
             go through namespaces.  */
          if (TREE_CODE (x) == NAMESPACE_DECL)
            set_identifier_type_value_with_scope (name, NULL_TREE, 
                                                  current_binding_level);

          /* If this is an extern function declaration, see if we
             have a global definition or declaration for the function.  */
          if (oldlocal == NULL_TREE
              && DECL_EXTERNAL (x)
              && oldglobal != NULL_TREE
              && TREE_CODE (x) == FUNCTION_DECL
              && TREE_CODE (oldglobal) == FUNCTION_DECL)
            {
              /* We have one.  Their types must agree.  */
              if (decls_match (x, oldglobal))
                /* OK */;
              else
                {
                  cp_warning ("extern declaration of `%#D' doesn't match", x);
                  cp_warning_at ("global declaration `%#D'", oldglobal);
                }
            }
          /* If we have a local external declaration,
             and no file-scope declaration has yet been seen,
             then if we later have a file-scope decl it must not be static.  */
          if (oldlocal == NULL_TREE
              && oldglobal == NULL_TREE
              && DECL_EXTERNAL (x)
              && TREE_PUBLIC (x))
            TREE_PUBLIC (name) = 1;

          if (DECL_FROM_INLINE (x))
            /* Inline decls shadow nothing.  */;

          /* Warn if shadowing an argument at the top level of the body.  */
          else if (oldlocal != NULL_TREE && !DECL_EXTERNAL (x)
                   && TREE_CODE (oldlocal) == PARM_DECL
                   /* Don't complain if it's from an enclosing function.  */
                   && DECL_CONTEXT (oldlocal) == current_function_decl
                   && TREE_CODE (x) != PARM_DECL)
            {
              /* Go to where the parms should be and see if we
                 find them there.  */
              struct binding_level *b = current_binding_level->level_chain;

              if (cleanup_label)
                b = b->level_chain;

              /* ARM $8.3 */
              if (b->parm_flag == 1)
                cp_error ("declaration of `%#D' shadows a parameter", name);
            }
          else if (warn_shadow && oldlocal != NULL_TREE
                   && current_binding_level->is_for_scope
                   && !DECL_DEAD_FOR_LOCAL (oldlocal))
            {
              warning ("variable `%s' shadows local",
                       IDENTIFIER_POINTER (name));
              cp_warning_at ("  this is the shadowed declaration", oldlocal);
            }              
          /* Maybe warn if shadowing something else.  */
          else if (warn_shadow && !DECL_EXTERNAL (x)
                   /* No shadow warnings for internally generated vars.  */
                   && ! DECL_ARTIFICIAL (x)
                   /* No shadow warnings for vars made for inlining.  */
                   && ! DECL_FROM_INLINE (x))
            {
              const char *warnstring = NULL;

              if (oldlocal != NULL_TREE && TREE_CODE (oldlocal) == PARM_DECL)
                warnstring = "declaration of `%s' shadows a parameter";
              else if (IDENTIFIER_CLASS_VALUE (name) != NULL_TREE
                       && current_class_ptr
                       && !TREE_STATIC (name))
                warnstring = "declaration of `%s' shadows a member of `this'";
              else if (oldlocal != NULL_TREE)
                warnstring = "declaration of `%s' shadows previous local";
              else if (oldglobal != NULL_TREE)
                /* XXX shadow warnings in outer-more namespaces */
                warnstring = "declaration of `%s' shadows global declaration";

              if (warnstring)
                warning (warnstring, IDENTIFIER_POINTER (name));
            }
        }

      if (TREE_CODE (x) == FUNCTION_DECL)
        check_default_args (x);

      /* Keep count of variables in this level with incomplete type.  */
      if (TREE_CODE (x) == VAR_DECL
          && TREE_TYPE (x) != error_mark_node
          && ((TYPE_SIZE (TREE_TYPE (x)) == NULL_TREE
               && PROMOTES_TO_AGGR_TYPE (TREE_TYPE (x), ARRAY_TYPE))
              /* RTTI TD entries are created while defining the type_info.  */
              || (TYPE_LANG_SPECIFIC (TREE_TYPE (x))
                  && TYPE_BEING_DEFINED (TREE_TYPE (x)))))
        current_binding_level->incomplete 
          = tree_cons (NULL_TREE, x, current_binding_level->incomplete);
    }

  if (need_new_binding)
    add_decl_to_level (x, 
                       DECL_NAMESPACE_SCOPE_P (x)
                       ? NAMESPACE_LEVEL (CP_DECL_CONTEXT (x))
                       : current_binding_level);

  return x;
}

/* Same as pushdecl, but define X in binding-level LEVEL.  We rely on the
   caller to set DECL_CONTEXT properly.  */

static tree
pushdecl_with_scope (x, level)
     tree x;
     struct binding_level *level;
{
  register struct binding_level *b;
  tree function_decl = current_function_decl;

  current_function_decl = NULL_TREE;
  if (level->parm_flag == 2)
    {
      b = class_binding_level;
      class_binding_level = level;
      pushdecl_class_level (x);
      class_binding_level = b;
    }
  else
    {
      b = current_binding_level;
      current_binding_level = level;
      x = pushdecl (x);
      current_binding_level = b;
    }
  current_function_decl = function_decl;
  return x;
}

/* Like pushdecl, only it places X in the current namespace,
   if appropriate.  */

tree
pushdecl_namespace_level (x)
     tree x;
{
  register struct binding_level *b = current_binding_level;
  register tree t;

  t = pushdecl_with_scope (x, NAMESPACE_LEVEL (current_namespace));

  /* Now, the type_shadowed stack may screw us.  Munge it so it does
     what we want.  */
  if (TREE_CODE (x) == TYPE_DECL)
    {
      tree name = DECL_NAME (x);
      tree newval;
      tree *ptr = (tree *)0;
      for (; b != global_binding_level; b = b->level_chain)
        {
          tree shadowed = b->type_shadowed;
          for (; shadowed; shadowed = TREE_CHAIN (shadowed))
            if (TREE_PURPOSE (shadowed) == name)
              {
                ptr = &TREE_VALUE (shadowed);
                /* Can't break out of the loop here because sometimes
                   a binding level will have duplicate bindings for
                   PT names.  It's gross, but I haven't time to fix it.  */
              }
        }
      newval = TREE_TYPE (x);
      if (ptr == (tree *)0)
        {
          /* @@ This shouldn't be needed.  My test case "zstring.cc" trips
             up here if this is changed to an assertion.  --KR  */
          SET_IDENTIFIER_TYPE_VALUE (name, newval);
        }
      else
        {
          *ptr = newval;
        }
    }
  return t;
}

/* Like pushdecl, only it places X in GLOBAL_BINDING_LEVEL,
   if appropriate.  */

tree
pushdecl_top_level (x)
     tree x;
{
  push_to_top_level ();
  x = pushdecl_namespace_level (x);
  pop_from_top_level ();
  return x;
}

/* Make the declaration of X appear in CLASS scope.  */

void
pushdecl_class_level (x)
     tree x;
{
  /* Don't use DECL_ASSEMBLER_NAME here!  Everything that looks in class
     scope looks for the pre-mangled name.  */