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

/* Process declarations and variables for C compiler.
   Copyright (C) 1988, 92, 93, 94, 95, 1996 Free Software Foundation, Inc.
   Hacked 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 <stdio.h>
#include "config.h"
#include "tree.h"
#include "rtl.h"
#include "flags.h"
#include "cp-tree.h"
#include "decl.h"
#include "lex.h"
#include <sys/types.h>
#include <signal.h>
#include "obstack.h"
#include "defaults.h"

#define obstack_chunk_alloc xmalloc
#define obstack_chunk_free free

extern tree builtin_return_address_fndecl;

extern struct obstack permanent_obstack;

extern int current_class_depth;

extern tree cleanups_this_call;

extern tree static_ctors, static_dtors;

/* Stack of places to restore the search obstack back to.  */
   
/* Obstack used for remembering local class declarations (like
   enums and static (const) members.  */
#include "stack.h"
struct obstack decl_obstack;
static struct stack_level *decl_stack;

#ifndef CHAR_TYPE_SIZE
#define CHAR_TYPE_SIZE BITS_PER_UNIT
#endif

#ifndef SHORT_TYPE_SIZE
#define SHORT_TYPE_SIZE (BITS_PER_UNIT * MIN ((UNITS_PER_WORD + 1) / 2, 2))
#endif

#ifndef INT_TYPE_SIZE
#define INT_TYPE_SIZE BITS_PER_WORD
#endif

#ifndef LONG_TYPE_SIZE
#define LONG_TYPE_SIZE BITS_PER_WORD
#endif

#ifndef LONG_LONG_TYPE_SIZE
#define LONG_LONG_TYPE_SIZE (BITS_PER_WORD * 2)
#endif

#ifndef WCHAR_UNSIGNED
#define WCHAR_UNSIGNED 0
#endif

#ifndef FLOAT_TYPE_SIZE
#define FLOAT_TYPE_SIZE BITS_PER_WORD
#endif

#ifndef DOUBLE_TYPE_SIZE
#define DOUBLE_TYPE_SIZE (BITS_PER_WORD * 2)
#endif

#ifndef LONG_DOUBLE_TYPE_SIZE
#define LONG_DOUBLE_TYPE_SIZE (BITS_PER_WORD * 2)
#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 tree lookup_nested_type                  PROTO((tree, tree));
static char *redeclaration_error_message        PROTO((tree, tree));

tree define_function            
        PROTO((char *, tree, enum built_in_function, void (*)(), char *));

/* a node which has tree code ERROR_MARK, and whose type is itself.
   All erroneous expressions are replaced with this node.  All functions
   that accept nodes as arguments should avoid generating error messages
   if this node is one of the arguments, since it is undesirable to get
   multiple error messages from one error in the input.  */

tree error_mark_node;

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

/* INTEGER_TYPE and REAL_TYPE nodes for the standard data types */

tree short_integer_type_node;
tree integer_type_node;
tree long_integer_type_node;
tree long_long_integer_type_node;

tree short_unsigned_type_node;
tree unsigned_type_node;
tree long_unsigned_type_node;
tree long_long_unsigned_type_node;

tree ptrdiff_type_node;

tree unsigned_char_type_node;
tree signed_char_type_node;
tree char_type_node;
tree wchar_type_node;
tree signed_wchar_type_node;
tree unsigned_wchar_type_node;

tree wchar_decl_node;

tree float_type_node;
tree double_type_node;
tree long_double_type_node;

tree intQI_type_node;
tree intHI_type_node;
tree intSI_type_node;
tree intDI_type_node;

tree unsigned_intQI_type_node;
tree unsigned_intHI_type_node;
tree unsigned_intSI_type_node;
tree unsigned_intDI_type_node;

/* a VOID_TYPE node, and the same, packaged in a TREE_LIST.  */

tree void_type_node, void_list_node;
tree void_zero_node;

/* Nodes for types `void *' and `const void *'.  */

tree ptr_type_node, const_ptr_type_node;

/* Nodes for types `char *' and `const char *'.  */

tree string_type_node, const_string_type_node;

/* Type `char[256]' or something like it.
   Used when an array of char is needed and the size is irrelevant.  */

tree char_array_type_node;

/* Type `int[256]' or something like it.
   Used when an array of int needed and the size is irrelevant.  */

tree int_array_type_node;

/* Type `wchar_t[256]' or something like it.
   Used when a wide string literal is created.  */

tree wchar_array_type_node;

/* The bool data type, and constants */
tree boolean_type_node, boolean_true_node, boolean_false_node;

/* type `int ()' -- used for implicit declaration of functions.  */

tree default_function_type;

/* function types `double (double)' and `double (double, double)', etc.  */

tree double_ftype_double, double_ftype_double_double;
tree int_ftype_int, long_ftype_long;
tree float_ftype_float;
tree ldouble_ftype_ldouble;

/* Function type `int (const void *, const void *, size_t)' */
static tree int_ftype_cptr_cptr_sizet;

/* C++ extensions */
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;
tree opaque_type_node, signature_type_node;
tree sigtable_entry_type;

/* Array type `vtable_entry_type[]' */
tree vtbl_type_node;

/* In a destructor, the point at which all derived class destroying
   has been done, just before any base class destroying will be done.  */

tree dtor_label;

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

rtx last_dtor_insn;

/* In a constructor, the point at which we are ready to return
   the pointer to the initialized object.  */

tree ctor_label;

/* 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;

extern rtx cleanup_label, return_label;

/* 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.  */
rtx original_result_rtx;

/* Sequence of insns which represents base initialization.  */
tree base_init_expr;

/* C++: Keep these around to reduce calls to `get_identifier'.
   Identifiers for `this' in member functions and the auto-delete
   parameter for destructors.  */
tree this_identifier, in_charge_identifier;
tree ctor_identifier, dtor_identifier;
/* Used in pointer to member functions, in vtables, and in sigtables.  */
tree pfn_identifier, index_identifier, delta_identifier, delta2_identifier;
tree pfn_or_delta2_identifier, tag_identifier;
tree vt_off_identifier;

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

/* A list (chain of TREE_LIST nodes) of named label uses.
   The TREE_PURPOSE field is the list of variables defined
   the the label's scope defined at the point of use.
   The TREE_VALUE field is the LABEL_DECL used.
   The TREE_TYPE field holds `current_binding_level' at the
   point of the label's use.

   BWAHAHAAHAHahhahahahaah.  No, no, no, said the little chicken.

   Look at the pretty struct named_label_list. See the pretty struct
   with the pretty named fields that describe what they do. See the
   pretty lack of gratuitous casts. Notice the code got a lot cleaner.

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

static struct named_label_list *named_label_uses = NULL;

/* 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++ */

/* Two expressions that are constants with value zero.
   The first is of type `int', the second of type `void *'.  */

tree integer_zero_node;
tree null_pointer_node;

/* The value for __null (NULL), either of type `void *' or, with -ansi,
   an integer type of the same size.  */

tree null_node;

/* A node for the integer constants 1, 2, and 3.  */

tree integer_one_node, integer_two_node, integer_three_node;

/* Nonzero if we have seen an invalid cross reference
   to a struct, union, or enum, but not yet printed the message.  */

tree pending_invalid_xref;
/* File and line to appear in the eventual error message.  */
char *pending_invalid_xref_file;
int pending_invalid_xref_line;

/* 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 a list of parameter names
   or a chain or parameter decls here.  */

tree last_function_parms;

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

static tree last_function_parm_tags;

/* After parsing the declarator that starts a function definition,
   `start_function' puts here the list of parameter names or chain of decls.
   `store_parm_decls' finds it here.  */

static tree current_function_parms;

/* Similar, for last_function_parm_tags.  */
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.  */

static tree named_labels;

/* A list of LABEL_DECLs from outer contexts that are currently shadowed.  */

static tree shadowed_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, set to 1 if
   a return statement that specifies a return value is seen.  */

int current_function_returns_value;

/* Set to 0 at beginning of a function definition, set to 1 if
   a return statement with no argument is seen.  */

int current_function_returns_null;

/* 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;

/* Set to nonzero by `grokdeclarator' for a function
   whose return type is defaulted, if warnings for this are desired.  */

static int warn_about_return_type;

/* 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;

/* Pointers to the base and current top of the language name stack.  */

extern tree *current_lang_base, *current_lang_stack;
\f
/* C and C++ flags are in decl2.c.  */

/* Set to 0 at beginning of a constructor, set to 1
   if that function does an allocation before referencing its
   instance variable.  */
static int current_function_assigns_this;
int current_function_just_assigned_this;

/* Set to 0 at beginning of a function.  Set non-zero when
   store_parm_decls is called.  Don't call store_parm_decls
   if this flag is non-zero!  */
int current_function_parms_stored;

/* Flag used when debugging spew.c */

extern int spew_debug;

/* This is a copy of the class_shadowed list of the previous class binding
   contour when at global scope.  It's used to reset IDENTIFIER_CLASS_VALUEs
   when entering another class scope (i.e. a cache miss).  */
extern tree previous_class_values;

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

\f
/* Allocate a level of searching.  */

struct stack_level *
push_decl_level (stack, obstack)
     struct stack_level *stack;
     struct obstack *obstack;
{
  struct stack_level tem;
  tem.prev = stack;

  return push_stack_level (obstack, (char *)&tem, sizeof (tem));
}
\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.  */

/* 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.  */
    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;

    /* For each level, a list of shadowed outer-level local definitions
       to be restored when this level is popped.
       Each link is a TREE_LIST whose TREE_PURPOSE is an identifier and
       whose TREE_VALUE is its old definition (a kind of ..._DECL node).  */
    tree shadowed;

    /* Same, for IDENTIFIER_CLASS_VALUE.  */
    tree class_shadowed;

    /* Same, for IDENTIFIER_TYPE_VALUE.  */
    tree type_shadowed;

    /* 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.  */
    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;

    /* Two bits 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 (non-class) binding level currently in effect.  */

static struct binding_level *current_binding_level;

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

static struct binding_level *class_binding_level;

/* The current (class or non-class) binding level currently in effect.  */

#define inner_binding_level \
  (class_binding_level ? class_binding_level : current_binding_level)

/* 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;

/* Binding level structures are initialized by copying this one.  */

static struct binding_level clear_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.  */
  *newlevel = clear_binding_level;
  if (class_binding_level)
    {
      newlevel->level_chain = class_binding_level;
      class_binding_level = (struct binding_level *)0;
    }
  else
    {
      newlevel->level_chain = current_binding_level;
    }
  current_binding_level = newlevel;
  newlevel->tag_transparent = tag_transparent;
  newlevel->more_cleanups_ok = 1;
  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) */
}

static void
pop_binding_level ()
{
  if (class_binding_level)
    current_binding_level = class_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;

    class_binding_level = current_binding_level;
    if (class_binding_level->parm_flag != 2)
      class_binding_level = 0;
    while (current_binding_level->parm_flag == 2)
      current_binding_level = current_binding_level->level_chain;
  }
}

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;
    class_binding_level = current_binding_level;
    if (class_binding_level->parm_flag != 2)
      class_binding_level = 0;
    while (current_binding_level->parm_flag == 2)
      current_binding_level = current_binding_level->level_chain;
  }
}

void
resume_binding_level (b)
     struct binding_level *b;
{
  if (class_binding_level)
    {
#if 1
      /* These are here because we cannot deal with shadows yet.  */
      sorry ("cannot resume a namespace inside class");
      return;
#else
      b->level_chain = class_binding_level;
      class_binding_level = (struct binding_level *)0;
#endif
    }
  else
    {
#if 1
      /* These are here because we cannot deal with shadows yet.  */
      if (b->level_chain != current_binding_level)
        {
          sorry ("cannot resume a namespace inside a different namespace");
          return;
        }
#endif
      b->level_chain = current_binding_level;
    }
  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;
}

/* 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.  */

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

  while (1)
    {
      if (b == global_binding_level)
        return 1;
      if (b->pseudo_global)
        return 1;
      if (! b->namespace_p)
        return 0;
      b=b->level_chain;
    }
}

/* Nonzero if this is a namespace scope.  */

int
namespace_bindings_p ()
{
  return current_binding_level->namespace_p;
}

void
keep_next_level ()
{
  keep_next_level_flag = 1;
}

/* 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));
}

/* Identify this binding level as a level of parameters.  */

void
declare_parm_level ()
{
  current_binding_level->parm_flag = 1;
}

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

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;
{
  register struct binding_level *newlevel = NULL_BINDING_LEVEL;

  /* If this is the top level of a function,
     just make sure that NAMED_LABELS is 0.
     They should have been set to 0 at the end of the previous function.  */

  if (current_binding_level == global_binding_level)
    my_friendly_assert (named_labels == NULL_TREE, 134);

  /* 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);
}

/* 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 KEEP == 2, this level's subblocks go to the front,
   not the back of the current binding level.  This happens,
   for instance, when code for constructors and destructors
   need to generate code at the end of a function which must
   be moved up to the front of the function.

   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 = current_binding_level->keep == 2
    ? ((functionbody = 0), tmp) : functionbody;
  tree tags = functionbody >= 0 ? current_binding_level->tags : 0;
  tree subblocks = functionbody >= 0 ? current_binding_level->blocks : 0;
  tree block = NULL_TREE;
  tree decl;
  int block_previously_created;

  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;

  /* Clear out the meanings of the local variables of this level.  */

  if (current_binding_level->is_for_scope && flag_new_for_scope == 1)
    {
      struct binding_level *outer = current_binding_level->level_chain;
      for (link = decls; link; link = TREE_CHAIN (link))
        {
          if (TREE_CODE (link) == VAR_DECL)
            DECL_DEAD_FOR_LOCAL (link) = 1;
          else
            IDENTIFIER_LOCAL_VALUE (DECL_NAME (link)) = NULL_TREE;
        }

      /* Save declarations made in a 'for' statement so we can support pre-ANSI
         'for' scoping semantics.  */

      for (link = current_binding_level->shadowed; link; link = TREE_CHAIN (link))
        {
          tree id = TREE_PURPOSE (link);
          tree decl = IDENTIFIER_LOCAL_VALUE (id);

          if (decl && DECL_DEAD_FOR_LOCAL (decl))
            {
              /* In this case keep the dead for-decl visible,
                 but remember what (if anything) it shadowed.  */
              DECL_SHADOWED_FOR_VAR (decl) = TREE_VALUE (link);
              TREE_CHAIN (decl) = outer->dead_vars_from_for;
              outer->dead_vars_from_for = decl;
            }
          else
            IDENTIFIER_LOCAL_VALUE (id) = TREE_VALUE (link);
        }
    }
  else /* Not special for scope.  */
    {
      for (link = decls; link; link = TREE_CHAIN (link))
        {
          if (DECL_NAME (link) != NULL_TREE)
            {
              /* If the ident. was used or addressed via a local extern decl,
                 don't forget that fact.  */
              if (DECL_EXTERNAL (link))
                {
                  if (TREE_USED (link))
                    TREE_USED (DECL_ASSEMBLER_NAME (link)) = 1;
                  if (TREE_ADDRESSABLE (link))
                    TREE_ADDRESSABLE (DECL_ASSEMBLER_NAME (link)) = 1;
                }
              IDENTIFIER_LOCAL_VALUE (DECL_NAME (link)) = NULL_TREE;
            }
        }

      /* Restore all name-meanings of the outer levels
         that were shadowed by this level.  */

      for (link = current_binding_level->shadowed;
           link; link = TREE_CHAIN (link))
        IDENTIFIER_LOCAL_VALUE (TREE_PURPOSE (link)) = TREE_VALUE (link);

      /* We first restore the regular decls and *then* the dead_vars_from_for
         to handle this case:

         int i; // i#1
         {
           for (int i; ; ) { ...} // i#2
           int i; // i#3
         } // we are here

         In this case, we want remove the binding for i#3, restoring
         that of i#2.  Then we want to remove the binding for i#2,
         and restore that of i#1.  */

      link = current_binding_level->dead_vars_from_for;
      for (; link != NULL_TREE; link = TREE_CHAIN (link))
        {
          tree id = DECL_NAME (link);
          if (IDENTIFIER_LOCAL_VALUE (id) == link)
            IDENTIFIER_LOCAL_VALUE (id) = DECL_SHADOWED_FOR_VAR (link);
        }

      for (link = current_binding_level->class_shadowed;
           link; link = TREE_CHAIN (link))
        IDENTIFIER_CLASS_VALUE (TREE_PURPOSE (link)) = TREE_VALUE (link);
      for (link = current_binding_level->type_shadowed;
           link; link = TREE_CHAIN (link))
        IDENTIFIER_TYPE_VALUE (TREE_PURPOSE (link)) = TREE_VALUE (link);
    }

  /* If the level being exited is the top level of a function,
     check over all the labels.  */

  if (functionbody)
    {
      /* If 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;

      /* Clear out the definitions of all label names,
         since their scopes end here.  */

      for (link = named_labels; link; link = TREE_CHAIN (link))
        {
          register tree label = TREE_VALUE (link);

          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), NULL_TREE);

          /* Put the labels into the "variables" of the
             top-level block, so debugger can see them.  */
          TREE_CHAIN (label) = BLOCK_VARS (block);
          BLOCK_VARS (block) = label;
        }

      named_labels = NULL_TREE;
    }

  /* Any uses of undefined labels now operate under constraints
     of next binding contour.  */
  {
    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)
    {
      if (keep == 2)
        current_binding_level->blocks
          = chainon (subblocks, current_binding_level->blocks);
      else
        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;
}

/* Resume a binding level for a namespace.  */

void
resume_level (b)
     struct binding_level *b;
{
  tree decls, link;

  resume_binding_level (b);

  /* Resume the variable caches.  */
  decls = current_binding_level->names;

  /* Restore the meanings of the local variables of this level.  */

  for (link = decls; link; link = TREE_CHAIN (link))
    {
      /* If it doesn't have a name, there is nothing left to do with it.  */
      if (DECL_NAME (link) == NULL_TREE)
        continue;

      IDENTIFIER_LOCAL_VALUE (DECL_NAME (link)) = link;

      /* If this is a TYPE_DECL, push it into the type value slot.  */
      if (TREE_CODE (link) == TYPE_DECL)
        SET_IDENTIFIER_TYPE_VALUE (DECL_NAME (link), TREE_TYPE (link));
    }
}

/* 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);
}

/* Add BLOCK to the current list of blocks for this binding contour.  */

void
add_block_current_level (block)
     tree block;
{
  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);

  decl_stack = push_decl_level (decl_stack, &decl_obstack);
  class_binding_level = current_binding_level;
  class_binding_level->parm_flag = 2;
  /* We have just pushed into a new binding level.  Now, fake out the rest
     of the compiler.  Set the `current_binding_level' back to point to
     the most closely containing non-class binding level.  */
  do
    {
      current_binding_level = current_binding_level->level_chain;
    }
  while (current_binding_level->parm_flag == 2);
}

/* ...and a poplevel for class declarations.  FORCE is used to force
   clearing out of CLASS_VALUEs after a class definition.  */

tree
poplevel_class (force)
     int force;
{
  register struct binding_level *level = class_binding_level;
  tree block = NULL_TREE;
  tree shadowed;

  my_friendly_assert (level != 0, 354);
  
  decl_stack = pop_stack_level (decl_stack);
  for (shadowed = level->shadowed; shadowed; shadowed = TREE_CHAIN (shadowed))
    IDENTIFIER_LOCAL_VALUE (TREE_PURPOSE (shadowed)) = TREE_VALUE (shadowed);
  /* 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 || force)
    for (shadowed = level->class_shadowed;
         shadowed;
         shadowed = TREE_CHAIN (shadowed))
      IDENTIFIER_CLASS_VALUE (TREE_PURPOSE (shadowed)) = TREE_VALUE (shadowed);
  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))
    IDENTIFIER_TYPE_VALUE (TREE_PURPOSE (shadowed)) = TREE_VALUE (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);

  if (class_binding_level->parm_flag != 2)
    class_binding_level = (struct binding_level *)0;

  /* Now, pop out of the 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 ();

  return block;
}
\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 (TREE_CODE (t) == ERROR_MARK)
            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->shadowed)
    {
      fprintf (stderr, " shadowed:");
      for (t = lvl->shadowed; t; t = TREE_CHAIN (t))
        {
          fprintf (stderr, " %s ", IDENTIFIER_POINTER (TREE_PURPOSE (t)));
        }
      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);
}

extern char * first_global_object_name;

/* Get a unique name for each call to this routine for unnamed namespaces.
   Mostly copied from get_file_function_name.  */

static tree
get_unique_name ()
{
  static int temp_name_counter = 0;
  char *buf;
  register char *p;

  if (first_global_object_name)
    p = first_global_object_name;
  else if (main_input_filename)
    p = main_input_filename;
  else
    p = input_filename;

#define UNNAMED_NAMESPACE_FORMAT "__%s_%d"

  buf = (char *) alloca (sizeof (UNNAMED_NAMESPACE_FORMAT) + strlen (p));

  sprintf (buf, UNNAMED_NAMESPACE_FORMAT, p, temp_name_counter++);

  /* Don't need to pull weird characters out of global names.  */
  if (p != first_global_object_name)
    {
      for (p = buf+11; *p; p++)
        if (! ((*p >= '0' && *p <= '9')
#ifndef NO_DOLLAR_IN_LABEL      /* this for `$'; unlikely, but... -- kr */
               || *p == '$'
#endif
#ifndef NO_DOT_IN_LABEL         /* this for `.'; unlikely, but...  */
               || *p == '.'
#endif
               || (*p >= 'A' && *p <= 'Z')
               || (*p >= 'a' && *p <= 'z')))
          *p = '_';
    }

  return get_identifier (buf);
}

/* 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;
{
  extern tree current_namespace;
  tree old_id = get_namespace_id ();
  char *buf;
  tree d;

  if (! name)
    {
      /* Create a truly ugly name! */
      name = get_unique_name ();
    }

  d = build_lang_decl (NAMESPACE_DECL, name, void_type_node);

  /* Mark them as external, so redeclaration_error_message doesn't think
     they are duplicates.  */

  DECL_EXTERNAL (d) = 1;
  d = pushdecl (d);

  if (NAMESPACE_LEVEL (d) == 0)
    {
      /* This is new for this compilation unit.  */
      pushlevel (0);
      declare_namespace_level ();
      NAMESPACE_LEVEL (d) = current_binding_level;
    }
  else
    resume_level (NAMESPACE_LEVEL (d));

  /* This code is just is bit old now...  */ 
  current_namespace = tree_cons (NULL_TREE, name, current_namespace);
  buf = (char *) alloca (4 + (old_id ? IDENTIFIER_LENGTH (old_id) : 0)
                         + IDENTIFIER_LENGTH (name));
  sprintf (buf, "%s%s", old_id ? IDENTIFIER_POINTER (old_id) : "",
           IDENTIFIER_POINTER (name));
  TREE_PURPOSE (current_namespace) = get_identifier (buf);
}

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

void
pop_namespace ()
{
  extern tree current_namespace;
  tree decls, link;
  current_namespace = TREE_CHAIN (current_namespace);

  /* Just in case we get out of sync.  */
  if (! namespace_bindings_p ())
    poplevel (0, 0, 0);

  decls = current_binding_level->names;

  /* Clear out the meanings of the local variables of this level.  */

  for (link = decls; link; link = TREE_CHAIN (link))
    {
      if (DECL_NAME (link) != NULL_TREE)
        {
          /* If the ident. was used or addressed via a local extern decl,
             don't forget that fact.  */
          if (DECL_EXTERNAL (link))
            {
              if (TREE_USED (link))
                TREE_USED (DECL_ASSEMBLER_NAME (link)) = 1;
              if (TREE_ADDRESSABLE (link))
                TREE_ADDRESSABLE (DECL_ASSEMBLER_NAME (link)) = 1;
            }
          IDENTIFIER_LOCAL_VALUE (DECL_NAME (link)) = NULL_TREE;
        }
    }

  /* Restore all name-meanings of the outer levels
     that were shadowed by this level.  */

  for (link = current_binding_level->shadowed; link; link = TREE_CHAIN (link))
    IDENTIFIER_LOCAL_VALUE (TREE_PURPOSE (link)) = TREE_VALUE (link);
  for (link = current_binding_level->class_shadowed;
       link; link = TREE_CHAIN (link))
    IDENTIFIER_CLASS_VALUE (TREE_PURPOSE (link)) = TREE_VALUE (link);
  for (link = current_binding_level->type_shadowed;
       link; link = TREE_CHAIN (link))
    IDENTIFIER_TYPE_VALUE (TREE_PURPOSE (link)) = TREE_VALUE (link);

  /* suspend a level.  */
  suspend_binding_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 {
  struct binding_level *old_binding_level;
  tree old_bindings;
  struct saved_scope *prev;
  tree class_name, class_type, function_decl;
  struct binding_level *class_bindings;
  tree *lang_base, *lang_stack, lang_name;
  int lang_stacksize;
  int minimal_parse_mode;
  tree last_function_parms;
  tree template_parms;
  HOST_WIDE_INT processing_template_decl;
  tree previous_class_type, previous_class_values;
};
static struct saved_scope *current_saved_scope;

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
          || (!IDENTIFIER_LOCAL_VALUE (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) = IDENTIFIER_TYPE_VALUE (id);
          TREE_VEC_ELT (binding, 2) = IDENTIFIER_LOCAL_VALUE (id);
          TREE_VEC_ELT (binding, 3) = IDENTIFIER_CLASS_VALUE (id);
          IDENTIFIER_LOCAL_VALUE (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;
{
  extern int current_lang_stacksize;
  struct saved_scope *s =
    (struct saved_scope *) xmalloc (sizeof (struct saved_scope));
  struct binding_level *b = inner_binding_level;
  tree old_bindings = NULL_TREE;

  if (current_function_decl)
    push_cp_function_context (NULL_TREE);

  if (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;

      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->old_binding_level = current_binding_level;
  current_binding_level = b;

  s->class_name = current_class_name;
  s->class_type = current_class_type;
  s->function_decl = current_function_decl;
  s->class_bindings = class_binding_level;
  s->lang_stack = current_lang_stack;
  s->lang_base = current_lang_base;
  s->lang_stacksize = current_lang_stacksize;
  s->lang_name = current_lang_name;
  s->minimal_parse_mode = minimal_parse_mode;
  s->last_function_parms = last_function_parms;
  s->template_parms = current_template_parms;
  s->processing_template_decl = processing_template_decl;
  s->previous_class_type = previous_class_type;
  s->previous_class_values = previous_class_values;

  current_class_name = current_class_type = NULL_TREE;
  current_function_decl = NULL_TREE;
  class_binding_level = (struct binding_level *)0;
  current_lang_stacksize = 10;
  current_lang_stack = current_lang_base
    = (tree *) xmalloc (current_lang_stacksize * sizeof (tree));
  current_lang_name = lang_name_cplusplus;
  strict_prototype = strict_prototypes_lang_cplusplus;
  named_labels = NULL_TREE;
  minimal_parse_mode = 0;
  previous_class_type = previous_class_values = NULL_TREE;
  if (!pseudo)
    {
      current_template_parms = NULL_TREE;
      processing_template_decl = 0;
    }

  s->prev = current_saved_scope;
  s->old_bindings = old_bindings;
  current_saved_scope = s;

  push_obstacks (&permanent_obstack, &permanent_obstack);
}

void
push_to_top_level ()
{
  maybe_push_to_top_level (0);
}

void
pop_from_top_level ()
{
  extern int current_lang_stacksize;
  struct saved_scope *s = current_saved_scope;
  tree t;

  /* Clear out class-level bindings cache.  */
  if (previous_class_type)
    {
      popclass (-1);
      previous_class_type = NULL_TREE;
    }

  pop_obstacks ();

  current_binding_level = s->old_binding_level;
  current_saved_scope = s->prev;
  for (t = s->old_bindings; t; t = TREE_CHAIN (t))
    {
      tree id = TREE_VEC_ELT (t, 0);
      if (id)
        {
          IDENTIFIER_TYPE_VALUE (id) = TREE_VEC_ELT (t, 1);
          IDENTIFIER_LOCAL_VALUE (id) = TREE_VEC_ELT (t, 2);
          IDENTIFIER_CLASS_VALUE (id) = TREE_VEC_ELT (t, 3);
        }
    }
  current_class_name = s->class_name;
  current_class_type = s->class_type;
  current_function_decl = s->function_decl;
  class_binding_level = s->class_bindings;
  free (current_lang_base);
  current_lang_base = s->lang_base;
  current_lang_stack = s->lang_stack;
  current_lang_name = s->lang_name;
  current_lang_stacksize = s->lang_stacksize;
  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;
  minimal_parse_mode = s->minimal_parse_mode;
  last_function_parms = s->last_function_parms;
  current_template_parms = s->template_parms;
  processing_template_decl = s->processing_template_decl;
  previous_class_type = s->previous_class_type;
  previous_class_values = s->previous_class_values;

  free (s);

  if (current_function_decl)
    pop_cp_function_context (NULL_TREE);
}
\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 != global_binding_level)
    {
      tree old_type_value = IDENTIFIER_TYPE_VALUE (id);
      b->type_shadowed
        = tree_cons (id, old_type_value, b->type_shadowed);
    }
  SET_IDENTIFIER_TYPE_VALUE (id, type);
}

/* As set_identifier_type_value_with_scope, but using inner_binding_level.  */

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

/* 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 () && ! pseudo_global_level_p ())
    {
      if (class_binding_level)
        pop_nested_class (1);
      else
        poplevel (0, 0, 0);
    }
#ifdef DEBUG_CP_BINDING_LEVELS
  fprintf (stderr, "XXX leaving pop_everything ()\n");
#endif
}

/* Push a tag name NAME for struct/class/union/enum type TYPE.
   Normally put into 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;
  tree context = 0;
  tree c_decl = 0;

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

  if (toplevel_bindings_p ())
    b->tags = perm_tree_cons (name, type, b->tags);
  else
    b->tags = saveable_tree_cons (name, type, b->tags);

  if (name)
    {
      context = type ? TYPE_CONTEXT (type) : NULL_TREE;
      if (! context && ! globalize)
        context = current_scope ();
      if (context)
        c_decl = TREE_CODE (context) == FUNCTION_DECL
          ? context : TYPE_MAIN_DECL (context);

      /* Do C++ gratuitous typedefing.  */
      if (IDENTIFIER_TYPE_VALUE (name) != type)
        {
          register tree d;
          int newdecl = 0;
          
          if (b->parm_flag != 2
              || TYPE_SIZE (current_class_type) != NULL_TREE)
            {
              d = lookup_nested_type (type, c_decl);

              if (d == NULL_TREE)
                {
                  newdecl = 1;
                  d = build_decl (TYPE_DECL, name, type);
                  SET_DECL_ARTIFICIAL (d);
                  set_identifier_type_value_with_scope (name, type, b);
                }
              else
                d = TYPE_MAIN_DECL (d);

              TYPE_NAME (type) = d;
              DECL_CONTEXT (d) = context;
              if (! globalize && processing_template_decl && IS_AGGR_TYPE (type))
                push_template_decl (d);

              if (b->parm_flag == 2)
                d = pushdecl_class_level (d);
              else
                d = pushdecl_with_scope (d, b);
            }
          else
            {
              /* Make nested declarations go into class-level scope.  */
              newdecl = 1;
              d = build_decl (TYPE_DECL, name, type);
              SET_DECL_ARTIFICIAL (d);
              TYPE_NAME (type) = d;
              DECL_CONTEXT (d) = context;
              if (! globalize && processing_template_decl && IS_AGGR_TYPE (type))
                push_template_decl (d);

              d = pushdecl_class_level (d);
            }
          if (newdecl)
            {
              if (ANON_AGGRNAME_P (name))
                DECL_IGNORED_P (d) = 1;

              TYPE_CONTEXT (type) = DECL_CONTEXT (d);
              DECL_ASSEMBLER_NAME (d)
                = get_identifier (build_overload_name (type, 1, 1));
            }
        }
      if (b->parm_flag == 2)
        {
          TREE_NONLOCAL_FLAG (type) = 1;
          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 (TREE_CODE (newdecl) == FUNCTION_DECL
      && TREE_CODE (olddecl) == FUNCTION_DECL)
    {
      tree f1 = TREE_TYPE (newdecl);
      tree f2 = TREE_TYPE (olddecl);
      tree p1 = TYPE_ARG_TYPES (f1);
      tree p2 = TYPE_ARG_TYPES (f2);

      /* 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 (comptypes (TREE_TYPE (f1), TREE_TYPE (f2), 1))
        {
          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, 3);
        }
      else
        types_match = 0;
    }
  else if (TREE_CODE (newdecl) == TEMPLATE_DECL
           && TREE_CODE (olddecl) == TEMPLATE_DECL)
    {
        tree newargs = DECL_TEMPLATE_PARMS (newdecl);
        tree oldargs = DECL_TEMPLATE_PARMS (olddecl);
        int i, len = TREE_VEC_LENGTH (newargs);

        if (TREE_VEC_LENGTH (oldargs) != len)
          return 0;
        
        for (i = 0; i < len; i++)
          {
            tree newarg = TREE_VALUE (TREE_VEC_ELT (newargs, i));
            tree oldarg = TREE_VALUE (TREE_VEC_ELT (oldargs, i));
            if (TREE_CODE (newarg) != TREE_CODE (oldarg))
              return 0;
            else if (TREE_CODE (newarg) == TYPE_DECL)
              /* continue */;
            else if (! comptypes (TREE_TYPE (newarg), TREE_TYPE (oldarg), 1))
              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;
      /* Qualifiers must match, and they may be present on either, the type
         or the decl.  */
      else if ((TREE_READONLY (newdecl)
                || TYPE_READONLY (TREE_TYPE (newdecl)))
               == (TREE_READONLY (olddecl)
                   || TYPE_READONLY (TREE_TYPE (olddecl)))
               && (TREE_THIS_VOLATILE (newdecl)
                    || TYPE_VOLATILE (TREE_TYPE (newdecl)))
                   == (TREE_THIS_VOLATILE (olddecl)
                       || TYPE_VOLATILE (TREE_TYPE (olddecl))))
        types_match = comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (newdecl)),
                                 TYPE_MAIN_VARIANT (TREE_TYPE (olddecl)), 1);
      else
        types_match = 0;
    }

  return types_match;
}

/* If NEWDECL is `static' and an `extern' was seen previously,
   warn about it.  (OLDDECL may be NULL_TREE; NAME contains
   information about previous usage as an `extern'.)

   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;
{
  tree name;

  static char *explicit_extern_static_warning
    = "`%D' was declared `extern' and later `static'";
  static char *implicit_extern_static_warning
    = "`%D' was declared implicitly `extern' and later `static'";

  if (TREE_CODE (newdecl) == TYPE_DECL)
    return;

  name = DECL_ASSEMBLER_NAME (newdecl);
  if (TREE_PUBLIC (name) && DECL_THIS_STATIC (newdecl))
    {
      /* It's okay to redeclare an ANSI built-in function as static,
         or to declare a non-ANSI built-in function as anything.  */
      if (! (TREE_CODE (newdecl) == FUNCTION_DECL
             && olddecl != NULL_TREE
             && TREE_CODE (olddecl) == FUNCTION_DECL
             && (DECL_BUILT_IN (olddecl)
                 || DECL_BUILT_IN_NONANSI (olddecl))))
        {
          cp_pedwarn (IDENTIFIER_IMPLICIT_DECL (name)
                      ? implicit_extern_static_warning
                      : explicit_extern_static_warning, newdecl);
          if (olddecl != NULL_TREE)
            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)
     register tree newdecl, olddecl;
{
  extern struct obstack permanent_obstack;
  unsigned olddecl_uid = DECL_UID (olddecl);
  int olddecl_friend = 0, types_match = 0;
  int new_defines_function;

  if (newdecl == olddecl)
    return 1;

  if (TREE_CODE_CLASS (TREE_CODE (olddecl)) == 'd')
    DECL_MACHINE_ATTRIBUTES (newdecl) = DECL_MACHINE_ATTRIBUTES (olddecl);

  types_match = decls_match (newdecl, olddecl);

  if (TREE_CODE (olddecl) != TREE_LIST)
    olddecl_friend = DECL_LANG_SPECIFIC (olddecl) && DECL_FRIEND_P (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 well just pretent the types match here.  */
  if ((TREE_TYPE (newdecl)
       && TREE_CODE (TREE_TYPE (newdecl)) == ERROR_MARK)
      || (TREE_TYPE (olddecl)
          && TREE_CODE (TREE_TYPE (olddecl)) == ERROR_MARK))
    types_match = 1;

  if (TREE_CODE (olddecl) == FUNCTION_DECL
      && DECL_ARTIFICIAL (olddecl)
      && (DECL_BUILT_IN (olddecl) || DECL_BUILT_IN_NONANSI (olddecl)))
    {
      /* 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.  Ditto for overloads.  */
      if (! DECL_PUBLIC (newdecl)
          || (TREE_CODE (newdecl) == FUNCTION_DECL
              && DECL_LANGUAGE (newdecl) != DECL_LANGUAGE (olddecl)))
        {
          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;
        }
      else if (! types_match)
        {
          if (TREE_CODE (newdecl) != FUNCTION_DECL)
            {
              /* If the built-in is not ansi, then programs can override
                 it even globally without an error.  */
              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;
            }

          cp_warning ("declaration of `%#D'", newdecl);
          cp_warning ("conflicts with built-in declaration `%#D'",
                      olddecl);
        }
    }
  else if (TREE_CODE (olddecl) != TREE_CODE (newdecl))
    {
      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 (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))), 3))
            {
              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)), 3))
            {
              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
    {
      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)
                          && current_binding_level == global_binding_level)
                         ? "`%#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 == current_lang_base)
            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 (TREE_CODE (olddecl) == FUNCTION_DECL
          && ! DECL_USE_TEMPLATE (olddecl))
        {
          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 ("conflicts with 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);
            }
        }
      /* These bits are logically part of the type for non-functions.  */
      else if (TREE_READONLY (newdecl) != TREE_READONLY (olddecl)
               || TREE_THIS_VOLATILE (newdecl) != TREE_THIS_VOLATILE (olddecl))
        {
          cp_pedwarn ("type qualifiers for `%#D'", newdecl);
          cp_pedwarn_at ("conflict with previous decl `%#D'", 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_CHAIN (newdecl) == NULL_TREE)
        DECL_CHAIN (newdecl) = DECL_CHAIN (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);
    }

  /* 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);
        }
    }

  /* Special handling ensues if new decl is a function definition.  */
  new_defines_function = (TREE_CODE (newdecl) == FUNCTION_DECL
                          && 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 (tentative) definition.  */
      && !(DECL_EXTERNAL (olddecl) && ! DECL_EXTERNAL (newdecl)))
    {
      cp_warning ("redundant redeclaration of `%D' in same scope", newdecl);
      cp_warning_at ("previous declaration of `%D'", olddecl);
    }

  /* Copy all the DECL_... slots specified in the new decl
     except for any that we copy here from the old type.  */

  if (TREE_CODE (newdecl) == TEMPLATE_DECL)
    {
      TREE_TYPE (olddecl) = TREE_TYPE (newdecl);
      DECL_TEMPLATE_RESULT (olddecl) = DECL_TEMPLATE_RESULT (newdecl);
      DECL_TEMPLATE_PARMS (olddecl) = DECL_TEMPLATE_PARMS (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_obstacks_nochange ();
          end_temporary_allocation ();
        }

      /* 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 (! compexcepttypes (TREE_TYPE (newdecl), TREE_TYPE (olddecl)))
            {
              cp_error ("declaration of `%D' throws different exceptions...",
                        newdecl);
              cp_error_at ("...from previous declaration here", olddecl);
            }
        }
      TREE_TYPE (newdecl) = TREE_TYPE (olddecl) = newtype;

      /* Lay the type out, unless already done.  */
      if (oldtype != TREE_TYPE (newdecl)
          && 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);
        }

      /* 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, unless it's the
         call to abort() used for abstract virtuals.  */
      if ((DECL_LANG_SPECIFIC (olddecl)
           && !DECL_ABSTRACT_VIRTUAL_P (olddecl))
          || DECL_RTL (olddecl) != DECL_RTL (abort_fndecl))
        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 (TREE_CODE (newdecl) == FUNCTION_DECL)
    DECL_C_STATIC (newdecl) |= DECL_C_STATIC (olddecl);

  if (DECL_LANG_SPECIFIC (newdecl))
    {
      DECL_INTERFACE_KNOWN (newdecl) |= DECL_INTERFACE_KNOWN (olddecl);
      DECL_NOT_REALLY_EXTERN (newdecl) |= DECL_NOT_REALLY_EXTERN (olddecl);
    }

  if (TREE_CODE (newdecl) == FUNCTION_DECL)
    {
      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.  */
          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 redeclaring a builtin function, and not a definition,
             it stays built in.  */
          if (DECL_BUILT_IN (olddecl))
            {
              DECL_BUILT_IN (newdecl) = 1;
              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);
    }

  if (TREE_CODE (newdecl) == TEMPLATE_DECL)
    {
      DECL_TEMPLATE_INSTANTIATIONS (newdecl)
        = DECL_TEMPLATE_INSTANTIATIONS (olddecl);
      if (DECL_CHAIN (newdecl) == NULL_TREE)
        DECL_CHAIN (newdecl) = DECL_CHAIN (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);

  /* Don't really know how much of the language-specific
     values we should copy from old to new.  */
  if (DECL_LANG_SPECIFIC (olddecl))
    {
      DECL_IN_AGGR_P (newdecl) = DECL_IN_AGGR_P (olddecl);
      DECL_ACCESS (newdecl) = DECL_ACCESS (olddecl);
      DECL_NONCONVERTING_P (newdecl) = DECL_NONCONVERTING_P (olddecl);
      if (DECL_TEMPLATE_INFO (newdecl) == NULL_TREE)
        {
          DECL_TEMPLATE_INFO (newdecl) = DECL_TEMPLATE_INFO (olddecl);
          DECL_USE_TEMPLATE (newdecl) = DECL_USE_TEMPLATE (olddecl);
        }
    }

  if (TREE_CODE (newdecl) == FUNCTION_DECL)
    {
      int function_size;
      struct lang_decl *ol = DECL_LANG_SPECIFIC (olddecl);
      struct lang_decl *nl = DECL_LANG_SPECIFIC (newdecl);

      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));

      /* Can we safely free the storage used by newdecl?  */

#define ROUND(x) ((x + obstack_alignment_mask (&permanent_obstack)) \
                  & ~ obstack_alignment_mask (&permanent_obstack))

      if ((char *)newdecl + ROUND (function_size)
          + ROUND (sizeof (struct lang_decl))
          == obstack_next_free (&permanent_obstack))
        {
          DECL_MAIN_VARIANT (newdecl) = olddecl;
          DECL_LANG_SPECIFIC (olddecl) = ol;
          bcopy ((char *)nl, (char *)ol, sizeof (struct lang_decl));

          obstack_free (&permanent_obstack, newdecl);
        }
      else if (LANG_DECL_PERMANENT (ol) && ol != nl)
        {
          if (DECL_MAIN_VARIANT (olddecl) == olddecl)
            {
              /* Save these lang_decls that would otherwise be lost.  */
              extern tree free_lang_decl_chain;
              tree free_lang_decl = (tree) ol;

              if (DECL_LANG_SPECIFIC (olddecl) == ol)
                abort ();

              TREE_CHAIN (free_lang_decl) = free_lang_decl_chain;
              free_lang_decl_chain = free_lang_decl;
            }
          else
            {
              /* Storage leak.  */
            }
        }
    }
  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;

  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 = DECL_ASSEMBLER_NAME (x);
  register struct binding_level *b = current_binding_level;

  if (x != current_function_decl
      /* 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;
  /* A local declaration for a function doesn't constitute nesting.  */
  if (TREE_CODE (x) == FUNCTION_DECL && DECL_INITIAL (x) == 0)
    DECL_CONTEXT (x) = 0;

  /* 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

      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 ((TREE_CODE (t) == TYPE_DECL && DECL_ARTIFICIAL (t)
                   && TREE_CODE (x) != TYPE_DECL
                   && ! (TREE_CODE (x) == TEMPLATE_DECL
                         && TREE_CODE (DECL_TEMPLATE_RESULT (x)) == TYPE_DECL))
                  || (TREE_CODE (x) == TYPE_DECL && DECL_ARTIFICIAL (x)
                      && TREE_CODE (t) != TYPE_DECL
                      && ! (TREE_CODE (t) == TEMPLATE_DECL
                            && (TREE_CODE (DECL_TEMPLATE_RESULT (t))
                                == 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.  */
                  ;
                }
              else 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;
            }
        }

      if (TREE_CODE (x) == FUNCTION_DECL && ! DECL_FUNCTION_MEMBER_P (x))
        {
          t = push_overloaded_decl (x, 1);
          if (t != x || DECL_LANGUAGE (x) == lang_c)
            return t;
        }
      else if (DECL_FUNCTION_TEMPLATE_P (x) && DECL_CONTEXT (x) == NULL_TREE)
        return push_overloaded_decl (x, 0);

      /* If declaring a type as a typedef, and the type has no known
         typedef name, install this TYPE_DECL as its typedef name.  */
      if (TREE_CODE (x) == TYPE_DECL)
        {
          tree type = TREE_TYPE (x);
          tree name = (type != error_mark_node) ? TYPE_NAME (type) : x;

          if (name == NULL_TREE || TREE_CODE (name) != TYPE_DECL)
            {
              /* If these are different names, and we're at the global
                 binding level, make two equivalent definitions.  */
              name = x;
              if (global_bindings_p ())
                TYPE_NAME (type) = x;
            }
          my_friendly_assert (TREE_CODE (name) == TYPE_DECL, 140);

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

      /* 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_GLOBAL_VALUE (name) != NULL_TREE
              && (DECL_EXTERNAL (IDENTIFIER_GLOBAL_VALUE (name))
                  || TREE_PUBLIC (IDENTIFIER_GLOBAL_VALUE (name))))
            decl = IDENTIFIER_GLOBAL_VALUE (name);
          else
            decl = NULL_TREE;

          if (decl
              /* If different sort of thing, we already gave an error.  */
              && TREE_CODE (decl) == TREE_CODE (x)
              && ! comptypes (TREE_TYPE (x), TREE_TYPE (decl), 1))
            {
              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 (b == global_binding_level)
        {
          /* 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 && DECL_PUBLIC (x))
            TREE_PUBLIC (name) = 1;

          /* Don't install an artificial TYPE_DECL if we already have
             another _DECL with that name.  */
          if (TREE_CODE (x) != TYPE_DECL
              || t == NULL_TREE
              || ! DECL_ARTIFICIAL (x))
            IDENTIFIER_GLOBAL_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_LOCAL_VALUE (name);
          tree oldglobal = IDENTIFIER_GLOBAL_VALUE (name);

          /* Don't install an artificial TYPE_DECL if we already have
             another _DECL with that name.  */
          if (TREE_CODE (x) != TYPE_DECL
              || t == NULL_TREE
              || ! DECL_ARTIFICIAL (x))
            {
              b->shadowed = tree_cons (name, oldlocal, b->shadowed);
              IDENTIFIER_LOCAL_VALUE (name) = x;
            }

          /* 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), b);

          /* 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, b);

          /* 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
              && 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 && b->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))
            {
              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)
                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)))))
        b->incomplete = tree_cons (NULL_TREE, x, b->incomplete);
    }

  /* Put decls on list in reverse order.
     We will reverse them later if necessary.  */
  TREE_CHAIN (x) = b->names;
  b->names = x;
  if (! (b != global_binding_level || TREE_PERMANENT (x)))
    my_friendly_abort (124);

  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 = current_binding_level;
  tree function_decl = current_function_decl;

  current_function_decl = NULL_TREE;
  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 GLOBAL_BINDING_LEVEL,
   if appropriate.  */

tree
pushdecl_top_level (x)
     tree x;
{
  register struct binding_level *b = inner_binding_level;
  register tree t = pushdecl_with_scope (x, global_binding_level);

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

void
push_overloaded_decl_top_level (x, forget)
     tree x;
     int forget;
{
  struct binding_level *b = current_binding_level;

  current_binding_level = global_binding_level;
  push_overloaded_decl (x, forget);
  current_binding_level = b;
}

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

tree
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.  */
  register tree name = DECL_NAME (x);

  if (name)
    {
      if (TYPE_BEING_DEFINED (current_class_type))
        {
          /* Check for inconsistent use of this name in the class body.
             Types, enums, and static vars are checked here; other
             members are checked in finish_struct.  */
          tree icv = IDENTIFIER_CLASS_VALUE (name);

          if (icv && icv != x
              /* Don't complain about inherited names.  */
              && id_in_current_class (name)
              /* Or shadowed tags.  */
              && !(TREE_CODE (icv) == TYPE_DECL
                   && DECL_CONTEXT (icv) == current_class_type))
            {
              cp_error ("declaration of identifier `%D' as `%#D'", name, x);
              cp_error_at ("conflicts with previous use in class as `%#D'",
                           icv);
            }
        }

      push_class_level_binding (name, x);
      if (TREE_CODE (x) == TYPE_DECL)
        {
          set_identifier_type_value (name, TREE_TYPE (x));
        }
    }
  return x;
}

/* This function is used to push the mangled decls for nested types into
   the appropriate scope.  Previously pushdecl_top_level was used, but that
   is incorrect for members of local classes.  */

void
pushdecl_nonclass_level (x)
     tree x;
{
  struct binding_level *b = current_binding_level;

  my_friendly_assert (b->parm_flag != 2, 180);

#if 0
  /* Get out of template binding levels */
  while (b->pseudo_global)
    b = b->level_chain;
#endif

  pushdecl_with_scope (x, b);
}

/* Make the declaration(s) of X appear in CLASS scope
   under the name NAME.  */

void
push_class_level_binding (name, x)
     tree name;
     tree x;
{
  if (TREE_CODE (x) == TYPE_DECL && DECL_ARTIFICIAL (x)
      && purpose_member (name, class_binding_level->class_shadowed))
    return;

  maybe_push_cache_obstack ();
  class_binding_level->class_shadowed
      = tree_cons (name, IDENTIFIER_CLASS_VALUE (name),
                   class_binding_level->class_shadowed);
  pop_obstacks ();
  IDENTIFIER_CLASS_VALUE (name) = x;
  obstack_ptr_grow (&decl_obstack, x);
}

/* Tell caller how to interpret a TREE_LIST which contains
   chains of FUNCTION_DECLS.  */

int
overloaded_globals_p (list)
     tree list;
{
  my_friendly_assert (TREE_CODE (list) == TREE_LIST, 142);

  /* Don't commit caller to seeing them as globals.  */
  if (TREE_NONLOCAL_FLAG (list))
    return -1;
  /* Do commit caller to not seeing them as globals.  */
  if (TREE_CODE (TREE_VALUE (list)) == TREE_LIST)
    return 0;
  /* Do commit caller to seeing them as globals.  */
  return 1;
}

/* DECL is a FUNCTION_DECL which may have other definitions already in
   place.  We get around this by making the value of the identifier point
   to a list of all the things that want to be referenced by that name.  It
   is then up to the users of that name to decide what to do with that
   list.

   DECL may also be a TEMPLATE_DECL, with a FUNCTION_DECL in its DECL_RESULT
   slot.  It is dealt with the same way.

   The value returned may be a previous declaration if we guessed wrong
   about what language DECL should belong to (C or C++).  Otherwise,
   it's always DECL (and never something that's not a _DECL).  */

tree
push_overloaded_decl (decl, forgettable)
     tree decl;
     int forgettable;
{
  tree orig_name = DECL_NAME (decl);
  tree old;
  int doing_global = (global_bindings_p () || ! forgettable);

  if (doing_global)
    {
      old = IDENTIFIER_GLOBAL_VALUE (orig_name);
      if (old && TREE_CODE (old) == FUNCTION_DECL
          && DECL_ARTIFICIAL (old)
          && (DECL_BUILT_IN (old) || DECL_BUILT_IN_NONANSI (old)))
        {
          if (duplicate_decls (decl, old))
            return old;
          old = NULL_TREE;
        }
    }
  else
    {
      old = IDENTIFIER_LOCAL_VALUE (orig_name);

      if (! purpose_member (orig_name, current_binding_level->shadowed))
        {
          current_binding_level->shadowed
            = tree_cons (orig_name, old, current_binding_level->shadowed);
          old = NULL_TREE;
        }
    }

  if (old)
    {
      if (TREE_CODE (old) == TYPE_DECL && DECL_ARTIFICIAL (old))
        {
          tree t = TREE_TYPE (old);
          if (IS_AGGR_TYPE (t) && warn_shadow
              && (! DECL_IN_SYSTEM_HEADER (decl)
                  || ! DECL_IN_SYSTEM_HEADER (old)))
            cp_warning ("`%#D' hides constructor for `%#T'", decl, t);
          old = NULL_TREE;
        }
      else if (is_overloaded_fn (old))
        {
          tree tmp;
          
          for (tmp = get_first_fn (old); tmp; tmp = DECL_CHAIN (tmp))
            if (decl == tmp || duplicate_decls (decl, tmp))
              return tmp;
        }
      else
        {
          cp_error_at ("previous non-function declaration `%#D'", old);
          cp_error ("conflicts with function declaration `%#D'", decl);
          return decl;
        }
    }

  if (old || TREE_CODE (decl) == TEMPLATE_DECL)
    {
      if (old && is_overloaded_fn (old))
        DECL_CHAIN (decl) = get_first_fn (old);
      else
        DECL_CHAIN (decl) = NULL_TREE;
      old = tree_cons (orig_name, decl, NULL_TREE);
      TREE_TYPE (old) = unknown_type_node;
    }
  else
    /* orig_name is not ambiguous.  */
    old = decl;

  if (doing_global)
    IDENTIFIER_GLOBAL_VALUE (orig_name) = old;
  else
    IDENTIFIER_LOCAL_VALUE (orig_name) = old;

  return decl;
}
\f
/* Generate an implicit declaration for identifier FUNCTIONID
   as a function of type int ().  Print a warning if appropriate.  */

tree
implicitly_declare (functionid)
     tree functionid;
{
  register tree decl;
  int temp = allocation_temporary_p ();

  push_obstacks_nochange ();

  /* Save the decl permanently so we can warn if definition follows.
     In ANSI C, warn_implicit is usually false, so the saves little space.
     But in C++, it's usually true, hence the extra code.  */
  if (temp && (! warn_implicit || toplevel_bindings_p ()))
    end_temporary_allocation ();

  /* We used to reuse an old implicit decl here,
     but this loses with inline functions because it can clobber
     the saved decl chains.  */
  decl = build_lang_decl (FUNCTION_DECL, functionid, default_function_type);

  DECL_EXTERNAL (decl) = 1;
  TREE_PUBLIC (decl) = 1;
  DECL_ARTIFICIAL (decl) = 1;

  /* ANSI standard says implicit declarations are in the innermost block.
     So we record the decl in the standard fashion.  */
  pushdecl (decl);
  rest_of_decl_compilation (decl, NULL_PTR, 0, 0);

  if (warn_implicit
      /* Only one warning per identifier.  */
      && IDENTIFIER_IMPLICIT_DECL (functionid) == NULL_TREE)
    {
      cp_pedwarn ("implicit declaration of function `%#D'", decl);
    }

  SET_IDENTIFIER_IMPLICIT_DECL (functionid, decl);

  pop_obstacks ();

  return decl;
}

/* Return zero if the declaration NEWDECL is valid
   when the declaration OLDDECL (assumed to be for the same name)
   has already been seen.
   Otherwise return an error message format string with a %s
   where the identifier should go.  */

static char *
redeclaration_error_message (newdecl, olddecl)
     tree newdecl, olddecl;
{
  if (TREE_CODE (newdecl) == TYPE_DECL)
    {
      /* Because C++ can put things into name space for free,
         constructs like "typedef struct foo { ... } foo"
         would look like an erroneous redeclaration.  */
      if (comptypes (TREE_TYPE (newdecl), TREE_TYPE (olddecl), 0))
        return 0;
      else
        return "redefinition of `%#D'";
    }
  else if (TREE_CODE (newdecl) == FUNCTION_DECL)
    {
      /* If this is a pure function, its olddecl will actually be
         the original initialization to `0' (which we force to call
         abort()).  Don't complain about redefinition in this case.  */
      if (DECL_LANG_SPECIFIC (olddecl) && DECL_ABSTRACT_VIRTUAL_P (olddecl))
        return 0;

      /* We'll complain about linkage mismatches in
         warn_extern_redeclared_static.  */

      /* defining the same name twice is no good.  */
      if (DECL_INITIAL (olddecl) != NULL_TREE
          && DECL_INITIAL (newdecl) != NULL_TREE)
        {
          if (DECL_NAME (olddecl) == NULL_TREE)
            return "`%#D' not declared in class";
          else
            return "redefinition of `%#D'";
        }
      return 0;
    }
  else if (TREE_CODE (newdecl) == TEMPLATE_DECL)
    {
      if ((TREE_CODE (DECL_TEMPLATE_RESULT (newdecl)) == FUNCTION_DECL
           && DECL_INITIAL (DECL_TEMPLATE_RESULT (newdecl))
           && DECL_INITIAL (DECL_TEMPLATE_RESULT (olddecl)))
          || (TREE_CODE (DECL_TEMPLATE_RESULT (newdecl)) == TYPE_DECL
              && TYPE_SIZE (TREE_TYPE (newdecl))
              && TYPE_SIZE (TREE_TYPE (olddecl))))
        return "redefinition of `%#D'";
      return 0;
    }
  else if (toplevel_bindings_p ())
    {
      /* Objects declared at top level:  */
      /* If at least one is a reference, it's ok.  */
      if (DECL_EXTERNAL (newdecl) || DECL_EXTERNAL (olddecl))
        return 0;
      /* Reject two definitions.  */
      return "redefinition of `%#D'";
    }
  else
    {
      /* Objects declared with block scope:  */
      /* Reject two definitions, and reject a definition
         together with an external reference.  */
      if (!(DECL_EXTERNAL (newdecl) && DECL_EXTERNAL (olddecl)))
        return "redeclaration of `%#D'";
      return 0;
    }
}
\f
/* Get the LABEL_DECL corresponding to identifier ID as a label.
   Create one if none exists so far for the current function.
   This function is called for both label definitions and label references.  */

tree
lookup_label (id)
     tree id;
{
  register tree decl = IDENTIFIER_LABEL_VALUE (id);

  if (current_function_decl == NULL_TREE)
    {
      error ("label `%s' referenced outside of any function",
             IDENTIFIER_POINTER (id));
      return NULL_TREE;
    }

  if ((decl == NULL_TREE
      || DECL_SOURCE_LINE (decl) == 0)
      && (named_label_uses == NULL
          || named_label_uses->names_in_scope != current_binding_level->names
          || named_label_uses->label_decl != decl))
    {
      struct named_label_list *new_ent;
      new_ent
        = (struct named_label_list*)oballoc (sizeof (struct named_label_list));
      new_ent->label_decl = decl;
      new_ent->names_in_scope = current_binding_level->names;
      new_ent->binding_level = current_binding_level;
      new_ent->lineno_o_goto = lineno;
      new_ent->filename_o_goto = input_filename;
      new_ent->next = named_label_uses;
      named_label_uses = new_ent;
    }

  /* Use a label already defined or ref'd with this name.  */
  if (decl != NULL_TREE)
    {
      /* But not if it is inherited and wasn't declared to be inheritable.  */
      if (DECL_CONTEXT (decl) != current_function_decl
          && ! C_DECLARED_LABEL_FLAG (decl))
        return shadow_label (id);
      return decl;
    }

  decl = build_decl (LABEL_DECL, id, void_type_node);

  /* Make sure every label has an rtx.  */
  label_rtx (decl);

  /* A label not explicitly declared must be local to where it's ref'd.  */
  DECL_CONTEXT (decl) = current_function_decl;

  DECL_MODE (decl) = VOIDmode;

  /* Say where one reference is to the label,
     for the sake of the error if it is not defined.  */
  DECL_SOURCE_LINE (decl) = lineno;
  DECL_SOURCE_FILE (decl) = input_filename;

  SET_IDENTIFIER_LABEL_VALUE (id, decl);

  named_labels = tree_cons (NULL_TREE, decl, named_labels);
  named_label_uses->label_decl = decl;

  return decl;
}

/* Make a label named NAME in the current function,
   shadowing silently any that may be inherited from containing functions
   or containing scopes.

   Note that valid use, if the label being shadowed
   comes from another scope in the same function,
   requires calling declare_nonlocal_label right away.  */

tree
shadow_label (name)
     tree name;
{
  register tree decl = IDENTIFIER_LABEL_VALUE (name);

  if (decl != NULL_TREE)
    {
      shadowed_labels = tree_cons (NULL_TREE, decl, shadowed_labels);
      SET_IDENTIFIER_LABEL_VALUE (name, NULL_TREE);
      SET_IDENTIFIER_LABEL_VALUE (decl, NULL_TREE);
    }

  return lookup_label (name);
}

/* Define a label, specifying the location in the source file.
   Return the LABEL_DECL node for the label, if the definition is valid.
   Otherwise return 0.  */

tree
define_label (filename, line, name)
     char *filename;
     int line;
     tree name;
{
  tree decl;

  if (minimal_parse_mode)
    {
      push_obstacks (&permanent_obstack, &permanent_obstack);
      decl = build_decl (LABEL_DECL, name, void_type_node);
      pop_obstacks ();
      DECL_SOURCE_LINE (decl) = line;
      DECL_SOURCE_FILE (decl) = filename;
      add_tree (decl);
      return decl;
    }

  decl = lookup_label (name);

  /* After labels, make any new cleanups go into their
     own new (temporary) binding contour.  */
  current_binding_level->more_cleanups_ok = 0;

  /* If label with this name is known from an outer context, shadow it.  */
  if (decl != NULL_TREE && DECL_CONTEXT (decl) != current_function_decl)
    {
      shadowed_labels = tree_cons (NULL_TREE, decl, shadowed_labels);
      SET_IDENTIFIER_LABEL_VALUE (name, NULL_TREE);
      decl = lookup_label (name);
    }

  if (name == get_identifier ("wchar_t"))
    cp_pedwarn ("label named wchar_t");

  if (DECL_INITIAL (decl) != NULL_TREE)
    {
      cp_error ("duplicate label `%D'", decl);
      return 0;
    }
  else
    {
      struct named_label_list *uses, *prev;
      int identified = 0;

      /* Mark label as having been defined.  */
      DECL_INITIAL (decl) = error_mark_node;
      /* Say where in the source.  */
      DECL_SOURCE_FILE (decl) = filename;
      DECL_SOURCE_LINE (decl) = line;

      prev = NULL;
      uses = named_label_uses;
      while (uses != NULL)
        if (uses->label_decl == decl)
          {
            struct binding_level *b = current_binding_level;
            while (b)
              {
                tree new_decls = b->names;
                tree old_decls = (b == uses->binding_level)
                                  ? uses->names_in_scope : NULL_TREE;
                while (new_decls != old_decls)
                  {
                    if (TREE_CODE (new_decls) == VAR_DECL
                        /* Don't complain about crossing initialization
                           of internal entities.  They can't be accessed,
                           and they should be cleaned up
                           by the time we get to the label.  */
                        && ! DECL_ARTIFICIAL (new_decls)
                        && ((DECL_INITIAL (new_decls) != NULL_TREE
                             && DECL_INITIAL (new_decls) != error_mark_node)
                            || TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (new_decls))))
                      {
                        if (! identified) 
                          {
                            cp_error ("jump to label `%D'", decl);
                            error_with_file_and_line (uses->filename_o_goto,
                                                      uses->lineno_o_goto,
                                                      "  from here");
                            identified = 1;
                        }
                        cp_error_at ("  crosses initialization of `%#D'",
                                     new_decls);
                      }
                    new_decls = TREE_CHAIN (new_decls);
                  }
                if (b == uses->binding_level)
                  break;
                b = b->level_chain;
              }

            if (prev != NULL)
              prev->next = uses->next;
            else
              named_label_uses = uses->next;

            uses = uses->next;
          }
        else
          {
            prev = uses;
            uses = uses->next;
          }
      current_function_return_value = NULL_TREE;
      return decl;
    }
}

struct cp_switch
{
  struct binding_level *level;
  struct cp_switch *next;
};

static struct cp_switch *switch_stack;

void
push_switch ()
{
  struct cp_switch *p
    = (struct cp_switch *) oballoc (sizeof (struct cp_switch));
  p->level = current_binding_level;
  p->next = switch_stack;
  switch_stack = p;
}

void
pop_switch ()
{
  switch_stack = switch_stack->next;
}

/* Same, but for CASE labels.  If DECL is NULL_TREE, it's the default.  */
/* XXX Note decl is never actually used. (bpk) */

void
define_case_label (decl)
     tree decl;
{
  tree cleanup = last_cleanup_this_contour ();
  struct binding_level *b = current_binding_level;
  int identified = 0;

  if (cleanup)
    {
      static int explained = 0;
      cp_warning_at ("destructor needed for `%#D'", TREE_PURPOSE (cleanup));
      warning ("where case label appears here");
      if (!explained)
        {
          warning ("(enclose actions of previous case statements requiring");
          warning ("destructors in their own binding contours.)");
          explained = 1;
        }
    }

  for (; b && b != switch_stack->level; b = b->level_chain)
    {
      tree new_decls = b->names;
      for (; new_decls; new_decls = TREE_CHAIN (new_decls))
        {
          if (TREE_CODE (new_decls) == VAR_DECL
              /* Don't complain about crossing initialization
                 of internal entities.  They can't be accessed,
                 and they should be cleaned up
                 by the time we get to the label.  */
              && ! DECL_ARTIFICIAL (new_decls)
              && ((DECL_INITIAL (new_decls) != NULL_TREE
                   && DECL_INITIAL (new_decls) != error_mark_node)
                  || TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (new_decls))))
            {
              if (! identified)
                error ("jump to case label");
              identified = 1;
              cp_error_at ("  crosses initialization of `%#D'",
                           new_decls);
            }
        }
    }

  /* After labels, make any new cleanups go into their
     own new (temporary) binding contour.  */

  current_binding_level->more_cleanups_ok = 0;
  current_function_return_value = NULL_TREE;
}
\f
/* Return the list of declarations of the current level.
   Note that this list is in reverse order unless/until
   you nreverse it; and when you do nreverse it, you must
   store the result back using `storedecls' or you will lose.  */

tree
getdecls ()
{
  return current_binding_level->names;
}

/* Return the list of type-tags (for structs, etc) of the current level.  */

tree
gettags ()
{
  return current_binding_level->tags;
}

/* Store the list of declarations of the current level.
   This is done for the parameter declarations of a function being defined,
   after they are modified in the light of any missing parameters.  */

static void
storedecls (decls)
     tree decls;
{
  current_binding_level->names = decls;
}

/* Similarly, store the list of tags of the current level.  */

static void
storetags (tags)
     tree tags;
{
  current_binding_level->tags = tags;
}
\f
/* Given NAME, an IDENTIFIER_NODE,
   return the structure (or union or enum) definition for that name.
   Searches binding levels from BINDING_LEVEL up to the global level.
   If THISLEVEL_ONLY is nonzero, searches only the specified context
   (but skips any tag-transparent contexts to find one that is
   meaningful for tags).
   FORM says which kind of type the caller wants;
   it is RECORD_TYPE or UNION_TYPE or ENUMERAL_TYPE.
   If the wrong kind of type is found, and it's not a template, an error is
   reported.  */

static tree
lookup_tag (form, name, binding_level, thislevel_only)
     enum tree_code form;
     tree name;
     struct binding_level *binding_level;
     int thislevel_only;
{
  register struct binding_level *level;

  for (level = binding_level; level; level = level->level_chain)
    {
      register tree tail;
      if (ANON_AGGRNAME_P (name))
        for (tail = level->tags; tail; tail = TREE_CHAIN (tail))
          {
            /* There's no need for error checking here, because
               anon names are unique throughout the compilation.  */
            if (TYPE_IDENTIFIER (TREE_VALUE (tail)) == name)
              return TREE_VALUE (tail);
          }
      else
        for (tail = level->tags; tail; tail = TREE_CHAIN (tail))
          {
            if (TREE_PURPOSE (tail) == name)
              {
                enum tree_code code = TREE_CODE (TREE_VALUE (tail));
                /* Should tighten this up; it'll probably permit
                   UNION_TYPE and a struct template, for example.  */
                if (code != form
                    && !(form != ENUMERAL_TYPE && code == TEMPLATE_DECL))
                  {
                    /* Definition isn't the kind we were looking for.  */
                    cp_error ("`%#D' redeclared as %C", TREE_VALUE (tail),
                              form);
                    return NULL_TREE;
                  }
                return TREE_VALUE (tail);
              }
          }
      if (thislevel_only && ! level->tag_transparent)
        {
          if (level->pseudo_global)
            {
              tree t = IDENTIFIER_GLOBAL_VALUE (name);
              if (t && TREE_CODE (t) == TEMPLATE_DECL
                  && TREE_CODE (DECL_TEMPLATE_RESULT (t)) == TYPE_DECL)
                return TREE_TYPE (t);
            }
          return NULL_TREE;
        }
      if (current_class_type && level->level_chain == global_binding_level)
        {
          /* Try looking in this class's tags before heading into
             global binding level.  */
          tree context = current_class_type;
          while (context)
            {
              switch (TREE_CODE_CLASS (TREE_CODE (context)))
                {
                tree these_tags;
                case 't':
                    these_tags = CLASSTYPE_TAGS (context);
                    if (ANON_AGGRNAME_P (name))
                      while (these_tags)
                        {
                          if (TYPE_IDENTIFIER (TREE_VALUE (these_tags))
                              == name)
                            return TREE_VALUE (tail);
                          these_tags = TREE_CHAIN (these_tags);
                        }
                    else
                      while (these_tags)
                        {
                          if (TREE_PURPOSE (these_tags) == name)
                            {
                              if (TREE_CODE (TREE_VALUE (these_tags)) != form)
                                {
                                  cp_error ("`%#D' redeclared as %C in class scope",
                                            TREE_VALUE (tail), form);
                                  return NULL_TREE;
                                }
                              return TREE_VALUE (tail);
                            }
                          these_tags = TREE_CHAIN (these_tags);
                        }
                    /* If this type is not yet complete, then don't
                       look at its context.  */
                    if (TYPE_SIZE (context) == NULL_TREE)
                      goto no_context;
                    /* Go to next enclosing type, if any.  */
                    context = DECL_CONTEXT (TYPE_MAIN_DECL (context));
                    break;
                case 'd':
                    context = DECL_CONTEXT (context);
                    break;
                default:
                    my_friendly_abort (10);
                }
              continue;
              no_context:
              break;
            }
        }
    }
  return NULL_TREE;
}

void
set_current_level_tags_transparency (tags_transparent)
     int tags_transparent;
{
  current_binding_level->tag_transparent = tags_transparent;
}

/* Given a type, find the tag that was defined for it and return the tag name.
   Otherwise return 0.  However, the value can never be 0
   in the cases in which this is used.

   C++: If NAME is non-zero, this is the new name to install.  This is
   done when replacing anonymous tags with real tag names.  */

static tree
lookup_tag_reverse (type, name)
     tree type;
     tree name;
{
  register struct binding_level *level;

  for (level = current_binding_level; level; level = level->level_chain)
    {
      register tree tail;
      for (tail = level->tags; tail; tail = TREE_CHAIN (tail))
        {
          if (TREE_VALUE (tail) == type)
            {
              if (name)
                TREE_PURPOSE (tail) = name;
              return TREE_PURPOSE (tail);
            }
        }
    }
  return NULL_TREE;
}
\f
/* Lookup TYPE in CONTEXT (a chain of nested types or a FUNCTION_DECL).
   Return the type value, or NULL_TREE if not found.  */

static tree
lookup_nested_type (type, context)
     tree type;
     tree context;
{
  if (context == NULL_TREE)
    return NULL_TREE;
  while (context)
    {
      switch (TREE_CODE (context))
        {
        case TYPE_DECL:
          {
            tree ctype = TREE_TYPE (context);
            tree match = value_member (type, CLASSTYPE_TAGS (ctype));
            if (match)
              return TREE_VALUE (match);
            context = DECL_CONTEXT (context);

            /* When we have a nested class whose&n